WO2016027908A1 - Surface protective film - Google Patents

Surface protective film Download PDF

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Publication number
WO2016027908A1
WO2016027908A1 PCT/JP2015/075804 JP2015075804W WO2016027908A1 WO 2016027908 A1 WO2016027908 A1 WO 2016027908A1 JP 2015075804 W JP2015075804 W JP 2015075804W WO 2016027908 A1 WO2016027908 A1 WO 2016027908A1
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WO
WIPO (PCT)
Prior art keywords
protective film
surface protective
buffer layer
meth
acrylate
Prior art date
Application number
PCT/JP2015/075804
Other languages
French (fr)
Japanese (ja)
Other versions
WO2016027908A8 (en
Inventor
克彦 堀米
雄一 倉田
知親 富永
Original Assignee
リンテック株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Priority claimed from JP2014166737A external-priority patent/JP6528259B2/en
Application filed by リンテック株式会社 filed Critical リンテック株式会社
Publication of WO2016027908A1 publication Critical patent/WO2016027908A1/en
Publication of WO2016027908A8 publication Critical patent/WO2016027908A8/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D4/00—Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers

Definitions

  • the present invention relates to a surface protective film in which a pressure-sensitive adhesive is laminated on one surface of a support, and in particular, a surface that is applied to the surface of various optical members and electronic members and used to protect the surface. It relates to a protective film.
  • camera lens units communication / sensor modules, motor units such as vibrators, imaging modules, etc., such as unitized optical and electronic components, prevent surface damage during processing, assembly, inspection, transportation, etc.
  • a surface protective film may be stuck on the exposed surface. The surface protective film is peeled off from the optical member or the electronic member when the surface protection is no longer necessary.
  • a base material of such a surface protective film for example, it is known to use a polyethylene terephthalate film from the viewpoint of obtaining transparency and a base material such as polyimide or polyethylene naphthalate from the viewpoint of heat resistance. (See Patent Document 1).
  • Patent Document 1 does not discuss workability such as punching process, pasting, and peeling of the surface protective film.
  • This invention is made
  • the inventors of the present invention have a support body in which the surface protective film has a specific bending resistance, and the support body reaches a compression load of 2 mN when an indenter having a predetermined shape is pushed in.
  • the present inventors have found that the above-mentioned problems can be solved by having a buffer layer having a pressing depth required to achieve a predetermined value or more, and the present invention has been completed. That is, the present invention provides the following [1] to [12].
  • a surface protective film that is applied to an optical member or an electronic member and used to protect the surface thereof, Comprising a support having a bending resistance of 5000 mN ⁇ cm or more and 45000 mN ⁇ cm or less, and an adhesive layer on one surface of the support,
  • the support has a buffer layer composed of at least one selected from a buffer layer-forming composition containing an energy beam polymerizable compound and a buffer layer-forming resin film, and has a tip curvature radius of 100 nm and a ridge angle of 115 °.
  • the composition for forming a buffer layer is a polymerizable compound having urethane (meth) acrylate (a1), an alicyclic group having 6 to 20 ring atoms or a heterocyclic group as the energy ray polymerizable compound ( The surface protective film according to any one of [1] to [5] above, comprising a2) and a polymerizable compound (a3) having a functional group.
  • the pressure-sensitive adhesive layer is made of an energy ray-curable pressure-sensitive adhesive composition.
  • the pressure-sensitive adhesive layer comprises an energy ray-curable pressure-sensitive adhesive composition containing an acrylic copolymer,
  • the acrylic copolymer contains a monomer component containing at least 5 to 50% by mass of an alkyl (meth) acrylate having an alkyl group having 1 or 2 carbon atoms and not containing a carboxyl group-containing monomer or less than 5% by mass.
  • the surface protective film according to any one of [1] to [9] above which is a copolymer.
  • a member with a surface protective film comprising: an optical member or an electronic member; and the surface protective film according to any one of the above [1] to [10] attached to a surface of the optical member or the electronic member.
  • a method of protecting the surface by applying the surface protective film according to any one of [1] to [10] to the surface of an optical member or an electronic member.
  • a surface protective film for an optical member or an electronic member that is excellent in the processability of the surface protective film and the workability at the time of pasting and peeling.
  • the “energy beam” means, for example, an ultraviolet ray or an electron beam, and an ultraviolet ray or an electron beam is preferable.
  • the “weight average molecular weight (Mw)” is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method, and specifically described in the examples. It is a value measured based on the method.
  • GPC gel permeation chromatography
  • (meth) acrylate” means both “acrylate” and “methacrylate”, and other similar terms are also the same.
  • the surface protective film of the present invention is used for affixing to an optical member or an electronic member and protecting the surface thereof, and a support and a pressure-sensitive adhesive layer provided on one surface of the support. Is provided. Hereinafter, each member of the surface protective film will be described.
  • the support body which the surface protective film of this invention has is a support body which has a buffer layer, Comprising:
  • the bending resistance is 5000 mN * cm or more and 45000 mN * cm or less.
  • the bending resistance of the support is preferably 5500 mN ⁇ cm or more, more preferably 6000 mN ⁇ cm or more, and preferably 42500 mN ⁇ cm or less, more preferably 40000 mN ⁇ cm or less. .
  • the bending resistance is a value measured and calculated by a method according to JIS L 1913, specifically, a method described in the examples.
  • the thickness of the support is not particularly limited as long as the bending resistance of the support is in the above range, but workability when the surface protective film of the present invention is attached to and peeled off from an optical member or an electronic member. From the viewpoint of improving the thickness, it is preferably 30 to 200 ⁇ m, more preferably 40 to 200 ⁇ m, still more preferably 50 to 150 ⁇ m.
  • the buffer layer of the support has a compressive load of 2 mN when the tip of a triangular pyramid-shaped indenter having a tip radius of curvature of 100 nm and a ridge angle of 115 ° is pushed into the buffer layer at a speed of 10 ⁇ m / min.
  • the indentation depth (Z) (hereinafter also simply referred to as “indentation depth (Z)”) required for the above is 2.5 ⁇ m or more.
  • the buffer layer is a layer composed of at least one selected from a buffer layer forming composition containing an energy ray polymerizable compound and a buffer layer forming resin film, and is a buffer layer forming composition containing an energy ray polymerizable compound.
  • a buffer layer is easy to enlarge indentation depth, it is preferable that it is a layer which consists of 1 or more types chosen from the composition for buffer layer formation containing an energy-beam polymeric compound.
  • the present inventors in the configuration of the surface protection film, by providing a buffer layer adjusted so that the indentation depth (Z) is 2.5 ⁇ m or more at a position in contact with the punching blade during processing, It has been found that the punching accuracy of the surface protective film can be improved and the size of the surface protective film can be accurately controlled.
  • the buffer layer becomes too hard, making it difficult for the punching blade to enter during the punching process, or protecting the surface against the punching blade. It is difficult to accurately control the size of the surface protective film after the punching process because the film becomes slippery.
  • the buffer layer is not excessively soft, so that the buffer layer does not stick to the punching blade even during the punching process. Since the buffer layer is not deformed and the surface protective film is not displaced when the punching blade comes into contact, the size of the surface protective film after the punching process can be easily controlled accurately.
  • the indentation depth (Z) is preferably 2.5 to 30.0 ⁇ m, more preferably 5.0 to 25.0 ⁇ m, still more preferably 8.0 to 20.0 ⁇ m, and still more.
  • the thickness is preferably 12.0 to 20.0 ⁇ m.
  • the indentation depth (Z) means a value measured by the method described in Examples. Further, the indentation depth (Z) appropriately changes the type and content of components contained in the composition for forming a buffer layer containing the energy beam polymerizable compound that forms the buffer layer, the degree of curing of the buffer layer, and the like. Thus, it is possible to adjust so as to belong to the above range. Moreover, it can also be adjusted to belong to the said range also by selecting suitably the raw material resin of the resin film for buffer layer formation which forms a buffer layer. In the surface protective film of the present invention, the buffer layer is preferably exposed on the surface opposite to the adhesive layer described later.
  • the energy beam polymerizable compound contained in the buffer layer forming composition is not particularly limited as long as it is a compound capable of forming a buffer layer having an indentation depth (Z) in the above range.
  • photocurable Resin or monomer can be used.
  • the energy ray polymerizable compound is urethane (meth) acrylate (a1), an alicyclic group having 6 to 20 ring atoms or a heterocyclic group.
  • a composition for forming a buffer layer comprising a polymerizable compound (a2) having a cyclic group and a polymerizable compound (a3) having a functional group is preferred.
  • the composition for buffer layer formation contains a photoinitiator, and may contain another additive and a resin component in the range which does not impair the effect of this invention.
  • a photoinitiator may contain another additive and a resin component in the range which does not impair the effect of this invention.
  • each component contained in the composition for buffer layer formation containing an energy beam polymeric compound is demonstrated.
  • the urethane (meth) acrylate (a1) used in the composition for forming a buffer layer containing an energy ray polymerizable compound is a compound having at least a (meth) acryloyl group and a urethane bond, and has a property of being polymerized and cured by irradiation with energy rays. It is what you have.
  • the urethane (meth) acrylate (a1) may be an oligomer, a high molecular weight product, or a mixture thereof, but a urethane (meth) acrylate oligomer is preferable.
  • the weight average molecular weight (Mw) of the component (a1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, still more preferably 3,000 to 20,000. Further, the number of (meth) acryloyl groups (hereinafter also referred to as “number of functional groups”) in the component (a1) may be monofunctional, bifunctional, or trifunctional or more, but is preferably monofunctional or bifunctional. .
  • the component (a1) can be obtained, for example, by reacting a (meth) acrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound and a polyvalent isocyanate compound.
  • a component (a1) individually or in combination of 2 or more types.
  • the polyol compound used as a raw material for the component (a1) is not particularly limited as long as it is a compound having two or more hydroxy groups.
  • Specific examples of the polyol compound include alkylene diol, polyether type polyol, polyester type polyol, and polycarbonate type polyol. Among these, a polyester type polyol is preferable.
  • the polyol compound may be a bifunctional diol, a trifunctional triol, or a tetrafunctional or higher polyol, but is preferably a bifunctional diol, and more preferably a polyester type diol.
  • polyvalent isocyanate compound examples include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, dicyclohexylmethane-2 , 4'-diisocyanate, ⁇ , ⁇ '-diisocyanate dimethylcyclohexane, etc .; 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene- And aromatic diisocyanates such as 1,5-diisocyanate.
  • Urethane (meth) acrylate (a1) can be obtained by reacting the terminal isocyanate urethane prepolymer obtained by reacting the above-described polyol compound with the polyvalent isocyanate compound with (meth) acrylate having a hydroxy group.
  • the (meth) acrylate having a hydroxy group is not particularly limited as long as it is a compound having a hydroxy group and a (meth) acryloyl group in at least one molecule.
  • the (meth) acrylate having a hydroxy group examples include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 4-hydroxycyclohexyl (meth).
  • Acrylate 5-hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, etc.
  • Hydroxy-alkyl (meth) acrylates hydroxy-group-containing (meth) acrylamides such as N-methylol (meth) acrylamide; vinyl alcohol, vinyl phenol, bisphenol
  • the reaction product obtained by the diglycidyl ester of Nord A (meth) acrylic acid is reacted, and the like.
  • hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.
  • the conditions for reacting the terminal isocyanate urethane prepolymer and the (meth) acrylate having a hydroxy group are preferably the conditions of reacting at 60 to 100 ° C. for 1 to 4 hours in the presence of a solvent and a catalyst added as necessary. .
  • the content of the component (a1) in the composition for forming a buffer layer containing the energy beam polymerizable compound is such that the indentation depth (Z) forms a buffer layer having the above-mentioned range.
  • the component (a2) used in the composition for forming a buffer layer containing an energy beam polymerizable compound is a polymerizable compound having an alicyclic group or heterocyclic group having 6 to 20 ring-forming atoms, and at least one (meth) A compound having an acryloyl group is preferred.
  • this component (a2) the film formability of the obtained composition for forming a buffer layer can be improved.
  • the number of ring-forming atoms of the alicyclic group or heterocyclic group contained in the component (a2) is preferably 6 to 20, more preferably 6 to 18, still more preferably 6 to 16, and still more preferably 7 to 12. It is.
  • the atoms forming the ring structure of the heterocyclic group include a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom.
  • the number of ring-forming atoms means the number of atoms constituting the ring itself of a compound having a structure in which atoms are bonded in a ring, and is not bonded to an atom (for example, bonded to an atom constituting the ring). Hydrogen atoms) and atoms included in a substituent when the ring is substituted by a substituent are not included in the number of ring-forming atoms.
  • Specific components (a2) include, for example, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, And alicyclic group-containing (meth) acrylates such as adamantane (meth) acrylate; heterocyclic group-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate and morpholine (meth) acrylate; In addition, you may use a component (a2) individually or in combination of 2 or more types. Among these, alicyclic group-containing (meth) acrylate is preferable, and isobornyl (meth) acrylate is more preferable.
  • the content of the component (a2) in the buffer layer forming composition containing the energy beam polymerizable compound is such that the indentation depth (Z) forms a buffer layer having the above-mentioned range, and the obtained buffer layer forming From the viewpoint of improving the film formability of the composition, it is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 25% with respect to the total amount (100% by mass) of the buffer layer forming composition. It is ⁇ 55 mass%, more preferably 30-50 mass%.
  • the component (a3) used in the buffer layer-forming composition containing the energy beam polymerizable compound is a polymerizable compound containing a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group, and at least one (meth) A compound having an acryloyl group is preferred.
  • Component (a3) has good compatibility with component (a1), the viscosity of the composition for forming a buffer layer is adjusted to an appropriate range, and the elastic modulus of the buffer layer formed from the composition is also appropriate. It can be a range. Therefore, by using this component (a3), it is possible to form a buffer layer having an indentation depth (Z) in the above range.
  • the component (a3) include a hydroxyl group-containing (meth) acrylate, an epoxy group-containing (meth) acrylate, an amide group-containing compound, and an amino group-containing (meth) acrylate.
  • Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxy Examples include butyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and phenylhydroxypropyl (meth) acrylate.
  • Examples of the epoxy group-containing (meth) acrylate include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.
  • amide group-containing compounds include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N -Methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide and the like.
  • amino group-containing (meth) acrylates include primary amino group-containing (meth) acrylates, secondary amino group-containing (meth) acrylates, and tertiary amino group-containing (meth) acrylates.
  • Examples of other polymerizable compounds having a functional group include vinyl compounds such as hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam.
  • vinyl compounds such as hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam.
  • a hydroxyl group-containing (meth) acrylate is preferable, and a hydroxyl group-containing (meta) having an aromatic ring such as phenylhydroxypropyl (meth) acrylate is preferred.
  • a hydroxyl group-containing (meta) having an aromatic ring such as phenylhydroxypropyl (meth) acrylate is preferred.
  • Acrylate is more preferred.
  • the content of the component (a3) in the buffer layer forming composition containing the energy beam polymerizable compound is such that the indentation depth (Z) forms a buffer layer in the above range, and the obtained buffer layer forming From the viewpoint of improving the film formability of the composition, it is preferably 5 to 40% by mass, more preferably 7 to 35% by mass, and still more preferably 10% with respect to the total amount (100% by mass) of the buffer layer forming composition. To 30% by mass, and more preferably 13 to 25% by mass.
  • the content ratio [(a2) / (a3)] (mass ratio) of (a2) and component (a3) contained in the components in the buffer layer forming composition is preferably 0.5 to 3 0.0, more preferably 1.0 to 3.0, still more preferably 1.3 to 3.0, and still more preferably 1.5 to 2.8. If the said content ratio is 0.5 or more, the film-forming property of the composition for buffer layer formation obtained can be made favorable. On the other hand, if the content ratio is 3.0 or less, a buffer layer having an indentation depth (Z) in the above range can be formed.
  • composition for forming a buffer layer containing the energy beam polymerizable compound may contain other polymerizable compounds other than the components (a1) to (a3) as long as the effects of the present invention are not impaired.
  • examples of other polymerizable compounds include alkyl (meth) acrylates having an alkyl group having 1 to 20 carbon atoms; vinyl compounds such as styrene: and the like. In addition, you may use these other polymeric compounds individually or in combination of 2 or more types.
  • the content of the other polymerizable compound in the composition for forming a buffer layer containing the energy beam polymerizable compound is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, and still more preferably 0 to 5% by mass. More preferably, it is 0 to 2% by mass.
  • the composition for forming the buffer layer containing the energy ray polymerizable compound may further contain a photopolymerization initiator from the viewpoint of shortening the polymerization time by light irradiation and reducing the light irradiation amount.
  • a photopolymerization initiator include photopolymerization initiators such as benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds, and photosensitizers such as amines and quinones.
  • 1-hydroxycyclohexyl phenyl ketone 2-hydroxy-2-methyl-1-phenyl-propan-1-one
  • benzoin benzoin methyl ether
  • benzoin ethyl ether benzoin isopropyl ether, etc.
  • photopolymerization initiators can be used alone or in combination of two or more.
  • the content of the photopolymerization initiator in the composition for forming a buffer layer containing the energy beam polymerizable compound is preferably 0.05 to 15 parts by mass with respect to 100 parts by mass of the total amount of the energy beam polymerizable compound.
  • the amount is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass.
  • the composition for buffer layer formation containing the said energy ray polymeric compound may contain another additive and a resin component in the range which does not impair the effect of this invention.
  • additives include antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, antistatic agents, flame retardants, and dyes.
  • the content of each additive in the composition for forming a buffer layer is preferably 0.01 to 6 parts by mass with respect to 100 parts by mass of the total amount of the energy beam polymerizable compound, More preferably, it is 0.1 to 3 parts by mass.
  • the buffer layer forming resin film (hereinafter also referred to as “buffer layer resin film”) is not particularly limited as long as it is a resin film capable of forming a buffer layer having an indentation depth (Z) in the above range. Absent.
  • a polyethylene film is used from the viewpoint of improving the adhesive force with the adhesive tape or the heat seal material. Is preferred.
  • the polyethylene resin that is a raw material for the polyethylene film include high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE).
  • the thickness of the buffer layer is not particularly limited as long as the bending resistance of the support is within the above range, but the workability when attaching and peeling the surface protective film of the present invention to an optical member or an electronic member is good. In view of the above, it is preferably 5 to 100 ⁇ m, more preferably 10 to 80 ⁇ m, and still more preferably 15 to 50 ⁇ m.
  • the support preferably further has a substrate.
  • the buffer layer is provided on one surface of the base material.
  • the substrate is not particularly limited as long as the bending resistance of the support is in the above range, but a resin film (hereinafter also referred to as “resin film for substrate”) is preferable from the viewpoint of water resistance and heat resistance.
  • the resin constituting the resin film for a substrate include polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, wholly aromatic polyester, polyamide, polyimide, polyacetal, polycarbonate, modified polyphenylene oxide, polyphenylene sulfide, and polysulfone.
  • the substrate may be a single layer film made of one or more or two or more resins selected from the above resins, or may be a film in which two or more of these resin films are laminated.
  • the base material used in the present invention may contain a filler, a colorant, an antistatic agent, an antioxidant, an organic lubricant, a catalyst, and the like as long as the effects of the present invention are not impaired.
  • the substrate may be transparent or opaque, and may be colored as desired.
  • the buffer layer or the pressure-sensitive adhesive layer described later contains an energy beam polymerizable compound
  • the buffer layer or the pressure-sensitive adhesive layer needs to have transparency to the wavelength of the energy beam used for curing the energy beam polymerizable compound. is there. That is, when ultraviolet rays are used as the energy rays, a light transmissive film is used as the substrate.
  • the base material when using an electron beam as an energy beam, the base material does not need to be light-transmitting, and a colored film may be used.
  • at least one surface of the base material used in the present invention may be subjected to an adhesion treatment such as a corona treatment, which will be described later.
  • a layer may be provided.
  • the thickness of the substrate is not particularly limited as long as the bending resistance of the support is in the above range, but is adjusted according to the performance required for the surface protective film, and is preferably 10 to 300 ⁇ m. Particularly preferred is 30 to 150 ⁇ m.
  • the support may further have a resin layer on the surface opposite to the surface on which the buffer layer of the substrate is provided.
  • the resin layer is not particularly limited as long as the bending resistance of the support is in the above range.
  • the same resin film as the buffer layer resin film described above can be used.
  • a polyethylene film is preferable.
  • high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or the like can be used as the resin that is a raw material for the polyethylene film.
  • the thickness of the resin layer is not particularly limited as long as the bending resistance of the support is within the above range, but the workability when the surface protective film of the present invention is attached to and peeled from an optical member or an electronic member is good. In view of the above, it is preferably 5 to 100 ⁇ m, more preferably 10 to 80 ⁇ m, and still more preferably 15 to 50 ⁇ m.
  • Adhesive layer Although it does not specifically limit as an adhesive which forms the adhesive layer which the surface protection film of this invention has, For example, an acrylic adhesive, a urethane adhesive, a silicone adhesive, a rubber adhesive, a polyester adhesive Is mentioned. These pressure-sensitive adhesives may be used alone or in combination of two or more.
  • the said adhesive it is preferable that it is an acrylic adhesive.
  • it is the said acrylic adhesive, it is generally an acrylic adhesive (henceforth an acrylic adhesive composition) containing an acrylic copolymer (A).
  • the acrylic copolymer (A) usually constitutes a pressure-sensitive adhesive component in the pressure-sensitive adhesive layer, and is hereinafter also referred to as a main polymer.
  • the main polymer constituting the pressure-sensitive adhesive component is acrylic.
  • a polymer other than the polymer (A) is used.
  • the acrylic copolymer (A) is obtained by copolymerizing a monomer component (hereinafter also referred to as “copolymer component”) containing an alkyl (meth) acrylate as a main monomer.
  • a monomer component hereinafter also referred to as “copolymer component”
  • alkyl (meth) acrylate include those having 1 to 18 carbon atoms in the alkyl group, such as methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, and butyl.
  • the acrylic copolymer (A) contains an alkyl (meth) acrylate as a copolymer component, preferably 50% by mass or more, more preferably 50 to 99.5% by mass, based on the total amount of the copolymer component. .
  • the acrylic copolymer (A) contains, as a copolymer component, an alkyl (meth) acrylate having an alkyl group having 1 or 2 carbon atoms out of the alkyl (meth) acrylate, based on the total amount of the copolymer component.
  • the content is preferably 5 to 50% by mass.
  • the adhesive strength particularly when the acrylic adhesive is an energy ray curable adhesive, the adhesive strength after irradiation with energy rays becomes too high, and the peeling performance is deteriorated. Can be suppressed. Further, the initial adhesive strength does not become too high, and sufficient reworkability can be obtained.
  • the acrylic copolymer (A) contains, as a copolymer component, an alkyl (meth) acrylate having an alkyl group having 1 or 2 carbon atoms in an amount of 10 to More preferably, it is contained in an amount of 40% by mass, more preferably 15-35% by mass.
  • alkyl (meth) acrylate having 1 or 2 carbon atoms in the alkyl group examples include methyl (meth) acrylate and ethyl (meth) acrylate. Among these, methyl acrylate and methyl methacrylate are preferable.
  • the acrylic copolymer (A) contains, as a copolymer component, an alkyl (meth) acrylate having an alkyl group with 3 or more carbon atoms in the alkyl (meth) acrylate, based on the total amount of the copolymer component.
  • the content is preferably 30 to 85% by mass.
  • the alkyl (meth) acrylate having 3 or more carbon atoms in the alkyl group is preferably an alkyl (meth) acrylate in which the alkyl group has 3 to 8 carbon atoms, and the alkyl group has 4 to 8 carbon atoms.
  • Alkyl (meth) acrylates are more preferred, and alkyl acrylates having an alkyl group with 4 to 8 carbon atoms are more preferred.
  • n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, and the like are preferable.
  • the acrylic copolymer (A) preferably contains a polymerizable monomer other than alkyl (meth) acrylate as the copolymer component, and specifically contains a functional group-containing monomer.
  • the functional group-containing monomer provides a functional group necessary for bonding an unsaturated group-containing compound, which will be described later, to the acrylic copolymer (A) and for reaction with a crosslinking agent, which will be described later.
  • the functional group-containing monomer is a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group in the molecule.
  • the acrylic copolymer (A) does not contain a carboxyl group-containing monomer as a copolymer component, or even if it contains a carboxyl group-containing monomer, the content thereof is the total amount of the copolymer component. It is preferable that the amount is less than 5% by mass.
  • the pressure-sensitive adhesive layer can suppress an excessive increase in the adhesive strength after irradiation with energy rays and can improve the peelability of the surface protective film. In addition, an excessive increase in initial adhesive force can be suppressed, and reworkability can be improved.
  • the content of the carboxyl group-containing monomer in the copolymer component is preferably less than 3% by mass, more preferably less than 1% by mass, and further, no carboxyl group-containing monomer is contained as a copolymer component.
  • the carboxyl group-containing monomer include acrylic acid, methacrylic acid, itaconic acid and the like.
  • a hydroxyl group-containing compound is preferably used, and more preferably, a hydroxyl group-containing (meth) acrylate is used.
  • the acrylic copolymer (A) is preferably obtained by copolymerizing a copolymer component containing 0.2 to 40% by mass of hydroxyl group-containing (meth) acrylate with respect to the total amount of the copolymer component. .
  • the acrylic copolymer (A) can be appropriately crosslinked with a crosslinking agent described later.
  • the content of the hydroxyl group-containing (meth) acrylate is more preferably 0.3 to 30% by mass, and further preferably 0.5 to 30% by mass.
  • an unsaturated group-containing compound to be described later can be appropriately introduced into the side chain while ensuring appropriate adhesive performance. It becomes possible to appropriately crosslink the polymer (A).
  • Specific examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and the like. Can be mentioned.
  • the above functional group-containing monomers may be used alone or in combination of two or more.
  • the acrylic copolymer (A) includes (meth) acrylic acid esters, dialkyl (meth) acrylamides, vinyl formate, vinyl acetate, styrene other than alkyl (meth) acrylate and functional group-containing monomers. , Vinyl acetate or the like may be included as a copolymer component.
  • (meth) acrylic acid esters other than (meth) acrylic acid alkyl esters and functional group-containing monomers (meth) acrylic acid alkoxyalkyl esters, (meth) acrylic acid alkyleneoxyalkyl esters, (meth) acrylic acid nonylphenoxy polyethylene Glycol, tetrahydrofuran furfuryl acrylate, diacrylates which are esters of polyether and acrylic acid, and the like may also be used.
  • dialkyl (meth) acrylamide dimethyl (meth) acrylamide, diethyl (meth) acrylamide and the like are used.
  • Dialkyl (meth) acrylamide is preferably used, for example, when the pressure-sensitive adhesive composition is an energy ray-curable pressure-sensitive adhesive composition and is an XY type described later.
  • dialkyl (meth) acrylamide as a constituent monomer, the compatibility of the energy beam curable acrylic copolymer with the energy beam polymerizable compound (B) such as a highly polar urethane acrylate is improved.
  • the weight average molecular weight of the acrylic copolymer is preferably 100,000 or more, more preferably 100,000 to 1,500,000, and further preferably 150,000 to 1,000,000.
  • the weight average molecular weight of the acrylic polymer here refers to the reaction of the unsaturated group-containing compound when an unsaturated group-containing compound described later is reacted to form an energy ray-curable acrylic polymer. It means the previous acrylic copolymer.
  • the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer may be a non-energy ray-curable pressure-sensitive adhesive composition or an energy-ray-curable pressure-sensitive adhesive composition, An agent composition is preferred.
  • the energy ray-curable pressure-sensitive adhesive composition is not particularly limited as long as it has energy ray curability, but an X-type one is used as a preferred embodiment.
  • the X-type energy ray-curable pressure-sensitive adhesive composition is one in which the main polymer itself constituting the pressure-sensitive adhesive component of the pressure-sensitive adhesive has energy beam curability.
  • an acrylic pressure-sensitive adhesive composition at least a part of the acrylic copolymer obtained by copolymerizing the above-described copolymer component is replaced with an energy ray curable acrylic copolymer having an unsaturated group in the side chain. It is a polymer.
  • the energy ray curable acrylic copolymer is obtained by reacting the above-mentioned acrylic copolymer with an unsaturated group-containing compound.
  • the unsaturated group-containing compound has a substituent capable of reacting with a functional group of the functional group-containing monomer constituting the acrylic copolymer (A).
  • This substituent varies depending on the type of functional group possessed by the functional group monomer.
  • the functional group is a hydroxyl group or a carboxyl group
  • the substituent is preferably an isocyanate group or an epoxy group.
  • the functional group is a carboxyl group
  • the substituent is preferably an isocyanate group or an epoxy group
  • the functional group is In the case of an amino group or a substituted amino group, an isocyanate group or the like is preferable as the substituent.
  • the functional group is an epoxy group, a carboxyl group is preferable as the substituent, and among these, an isocyanate group is preferable.
  • One such substituent is contained in each molecule of the unsaturated group-containing compound.
  • the unsaturated group-containing compound contains 1 to 5, preferably 1 to 2, energy beam polymerizable carbon-carbon double bonds per molecule.
  • the energy beam polymerizable carbon-carbon double bond is preferably a (meth) acryloyl group.
  • Specific examples of such unsaturated group-containing compounds include (meth) acryloyloxyethyl isocyanate, meta-isopropenyl- ⁇ , ⁇ -dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, allyl isocyanate, glycidyl (meth) acrylate, Examples include (meth) acrylic acid.
  • an acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; obtained by reaction of a diisocyanate compound or polyisocyanate compound, a polyol compound and hydroxyethyl (meth) acrylate.
  • acryloyl monoisocyanate compounds obtained by reaction of a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate.
  • a polymerizable group-containing polyalkyleneoxy compound represented by the following formula (1) can also be used.
  • R 1 is hydrogen or a methyl group, preferably a methyl group
  • R 2 to R 5 are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms, preferably hydrogen
  • n is 2 It is an integer above, preferably 2-4.
  • a plurality of R 2 to R 5 may be the same as or different from each other. That is, since n is 2 or more, the polymerizable group-containing polyalkyleneoxy group represented by the formula (1) contains 2 or more R 2 . In this case, two or more R 2 s may be the same or different. The same applies to R 3 to R 5 .
  • NCO represents an isocyanate group.
  • the unsaturated group-containing compound is usually about 10 to 100 equivalents with respect to 100 equivalents of the functional group of the acrylic copolymer (A). Since it can be used, it is preferably used in a proportion of about 15 to 95 equivalents, more preferably about 20 to 90 equivalents.
  • a compound having a (meth) acryloyl group and an isocyanate group is preferably used, and specifically, (meth) acryloyloxyethyl isocyanate is preferable.
  • a Y-type energy beam curable pressure-sensitive adhesive composition is used as another preferred embodiment.
  • the Y-type energy ray-curable pressure-sensitive adhesive composition contains an energy ray-polymerizable compound (B) separately from the main polymer constituting the pressure-sensitive adhesive component of the pressure-sensitive adhesive such as the acrylic copolymer (A). The energy beam curability is imparted.
  • energy ray polymerizable compound (B) energy ray polymerizable oligomers such as epoxy acrylate, urethane acrylate, polyester acrylate, and polyether acrylate, and energy ray polymerizable monomers are used.
  • energy ray polymerizable monomer a low molecular weight compound having two or more functional groups having at least two photopolymerizable carbon-carbon double bonds in the molecule is used. Specifically, trimethylolpropane tri (meth) is used.
  • Acrylate tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate or 1,4 -Butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate and the like are used.
  • urethane acrylate oligomers are preferably used.
  • the urethane acrylate oligomer is a compound including an isocyanate unit and a polyol unit and having a (meth) acryloyl group at the terminal.
  • terminal isocyanate urethane oligomers are produced by reaction of polyols having hydroxyl groups at the ends, such as polyether-type polyols and polyester-type polyols, with polyisocyanates. ) And the like obtained by reacting a compound having an acryloyl group.
  • Such urethane acrylate oligomers have energy ray curability due to the action of the (meth) acryloyl group.
  • Examples of the polyisocyanate used in the urethane acrylate oligomer include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylylene diisocyanate.
  • Examples of the compound having a (meth) acryloyl group include (meth) acrylates having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and polyethylene glycol (meth) acrylate.
  • Examples of the (meth) acrylate having a hydroxyl group include polyhydric alcohols such as pentaerythritol and partial esters of (meth) acrylic acid.
  • the urethane acrylate oligomer is preferably a bifunctional or higher functional group having two or more (meth) acryloyl groups in one molecule, but if not used in combination with the X type, a trifunctional or higher functional group is preferred. More than the group is more preferable. By using one having three or more functional groups, it is easy to lower the adhesive strength after irradiation with energy rays, and the peel performance of the surface protective film tends to be good.
  • the urethane acrylate oligomer usually has 12 functional groups or less.
  • the urethane acrylate oligomer preferably has a weight average molecular weight of 1000 to 15000, more preferably 1500 to 8500.
  • the energy beam polymerizable compound (B) is usually blended in an amount of 5 to 200 parts by mass with respect to 100 parts by mass of the acrylic copolymer (A) (main polymer). Is preferably 200 parts by mass, more preferably 70 to 150 parts by mass.
  • the energy ray-curable pressure-sensitive adhesive composition may be a composition using both X-type and Y-type (hereinafter referred to as XY type). That is, the acrylic pressure-sensitive adhesive contains the energy beam polymerizable compound (B) in addition to the acrylic polymer (A), and at least a part of the acrylic copolymer (A) is not present in the side chain. What is an energy ray curable acrylic copolymer having a saturated group can also be used as a preferred embodiment.
  • the breaking strength and breaking elongation of the pressure-sensitive adhesive layer are improved, and the adhesive residue on the adherend when the surface protective film is peeled is easily reduced.
  • the energy ray curable acrylic copolymer used for the XY type is the same as that used for the X type.
  • the energy ray polymerizable compound (B) used in the XY type is the same as that used in the Y type described above, and is preferably a urethane acrylate oligomer. It is more preferable to use isophorone diisocyanate, 1,3-bis- (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, etc.
  • polystyrene resin As a polyol which forms the polyol unit in urethane acrylate, it is preferable to use polypropylene glycol (PPG), polyethylene glycol (PEG), polytetramethylene glycol, polycarbonate diol, etc., and the number average molecular weight of these polyols Is preferably 300 to 2000, particularly preferably 500 to 1000.
  • the polyol preferably contains two or more kinds of polyols in order to improve the breaking stress and breaking elongation of the pressure-sensitive adhesive layer, and the polyol contains PPG and PEG. It is particularly preferred that it consists only of PPG and PEG.
  • the molar ratio of PPG to PEG is preferably 9: 1 to 1: 9, more preferably 9: 1 to 1: 4, and further preferably 4: 1 to 3: 2. Most preferably, the ratio is from 5: 2.5 to 6.5: 3.5.
  • the urethane acrylate oligomer in the XY type is preferably a bifunctional group having two (meth) acryloyl groups in one molecule. By using a bifunctional group, it becomes easy to increase the breaking strength and breaking elongation while improving the peeling performance and the adhesiveness.
  • the energy ray polymerizable compound (B) is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the acrylic copolymer (A) (main polymer). More preferably, it is part by mass.
  • the pressure-sensitive adhesive layer may have a crosslinked structure in which a main polymer such as an acrylic copolymer (A) is crosslinked.
  • a main polymer such as an acrylic copolymer (A)
  • the crosslinking agent (C) contained in the pressure-sensitive adhesive composition for crosslinking include organic polyvalent isocyanate compounds, organic polyvalent epoxy compounds, and organic polyvalent imine compounds. Among these, organic polyvalent isocyanate compounds are exemplified. Isocyanate compounds (isocyanate-based crosslinking agents) are preferred.
  • organic polyvalent isocyanate compounds include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these organic polyvalent isocyanate compounds, and these organic polyvalent isocyanate compounds.
  • examples thereof include terminal isocyanate urethane prepolymers obtained by reacting with a polyol compound.
  • organic polyvalent isocyanate compound examples include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4.
  • organic polyvalent epoxy compound examples include 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, Examples include ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, and diglycidyl amine.
  • organic polyvalent imine compound examples include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri- ⁇ -aziridinylpropionate, tetra Mention may be made of methylolmethane-tri- ⁇ -aziridinylpropionate and N, N′-toluene-2,4-bis (1-aziridinecarboxyamide) triethylenemelamine.
  • the content of the crosslinking agent (C) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, with respect to 100 parts by mass of the acrylic copolymer (A) (main polymer). Particularly preferably, it is used in a ratio of 0.5 to 8 parts by mass.
  • the content of the crosslinking agent (C) is not more than the above upper limit, the pressure-sensitive adhesive layer is prevented from being excessively crosslinked, and appropriate adhesive force is easily obtained.
  • by making the usage-amount of a crosslinking agent more than the said lower limit it is prevented that an adhesive adheres to an electronic member or an optical member.
  • an energy-beam curable adhesive composition contains a photoinitiator (D).
  • photopolymerization initiators include photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds, and photosensitizers such as amines and quinones.
  • 1-hydroxycyclohexyl phenyl ketone benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, ⁇ -chloranthraquinone Examples include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
  • blending a photoinitiator (D) the irradiation time and irradiation amount of the energy beam for hardening can be decreased.
  • the content of the photopolymerization initiator (D) is not particularly limited, but is preferably 0.1 to 10 parts by mass, more preferably 1 with respect to 100 parts by mass of the acrylic copolymer (A) (main polymer). Is 5 parts by mass.
  • the pressure-sensitive adhesive layer may be colored so that the light transmittance of the surface protective film is less than 50%. Since the visibility of the surface protective film is improved by coloring the pressure-sensitive adhesive layer, for example, the surface protective film is easily peeled from a release sheet described later by hand.
  • the light transmittance of the surface protective film is measured with a spectrophotometer UV-3600 manufactured by Shimadzu Corporation at a wavelength of 600 nm. The light transmittance is preferably about 10 to 40%.
  • the pressure-sensitive adhesive composition usually contains a dye and a pigment, and among them, a blue dye and a blue pigment are preferably contained.
  • the above-mentioned pressure-sensitive adhesives include antioxidants, softeners (plasticizers), deterioration inhibitors, antistatic agents, flame retardants, rust inhibitors, fillers, silicone compounds, silane coupling agents, chain transfer agents, and the like. Components other than the above components may be contained as appropriate.
  • the surface protective film preferably has a pressure-sensitive adhesive force before irradiation with energy rays of 1000 to 20000 mN / 25 mm. More preferably, it is 16000 mN / 25 m.
  • the adhesive strength before energy beam irradiation is 1000 mN / 25 m or more, the adhesive strength of the surface protective film to the optical member and the electronic member is increased, and the protective performance is improved.
  • the adhesive strength before energy beam irradiation can be adjusted by the type and blending ratio of alkyl (meth) acrylate, the amount of crosslinking agent used, and the like.
  • the surface protective film preferably has an adhesive strength of 0.1 to 100 mN / 25 mm, more preferably 20 to 90 mN / 25 mm after energy beam irradiation.
  • the adhesive strength after energy beam irradiation can be controlled by the type and amount of the energy beam polymerizable compound (B) and the amount of unsaturated groups introduced into the acrylic copolymer.
  • the initial stage adhesive force before energy beam irradiation of an adhesive layer is less than 10000 mN / 25mm.
  • the lower limit value of the initial adhesive strength is not particularly limited, but is usually 500 mN / 25 mm or more.
  • the initial adhesive strength is more preferably 3000 to 9500 mN / 25 mm.
  • the initial adhesive strength can be adjusted by the kind and blending ratio of the alkyl (meth) acrylate, the kind and blending ratio of the functional group-containing monomer, the amount of the crosslinking agent used, and the like.
  • the measuring method of the above-mentioned adhesive force and initial stage adhesive force is the value measured based on the method described below.
  • the surface protective film is cut to a width of 25 mm to form a sample, and is attached to the mirror surface of the silicon wafer as an adherend with a 2 kg roller in an environment of 23 ° C. and 50% relative humidity. After standing for 20 minutes in an environment of 23 ° C. and 50% relative humidity, the adhesive strength when peeled at 180 ° at a tensile speed of 300 mm / min is measured to obtain the adhesive strength before energy beam irradiation. In addition, the sample attached to the silicon wafer after standing for 20 minutes is irradiated with ultraviolet rays in a nitrogen atmosphere (illuminance: 230 mW / cm 2 , using a RAD-2000m / 12 manufactured by Lintec Corporation).
  • the adhesive force when peeled at 180 ° in a tensile rate of 300 mm / min in an environment of 23 ° C. and 50% relative humidity is measured and set as the adhesive strength after irradiation with energy rays.
  • the surface protective film is cut into a width of 25 mm to obtain a sample, and is attached to a silicon wafer as an adherend with a 2 kg roller in an environment of 23 ° C. and 50% relative humidity.
  • the adhesive strength when peeled at 180 ° in a tensile rate of 300 mm / min in an environment of 23 ° C. and 50% relative humidity is measured, and the adhesive strength is taken as the initial adhesive strength.
  • the thickness of the pressure-sensitive adhesive layer is not particularly limited, and is preferably 3 to 50 ⁇ m, more preferably 5 to 30 ⁇ m. It becomes easy to improve the adhesiveness with respect to a to-be-adhered body because the thickness of an adhesive layer exists in the said range.
  • a surface protection film may provide an adhesive layer partially on a support body, and may form a non-adhesion part with an adhesion part on a support body.
  • screen printing or inkjet printing may be performed.
  • the adhesive portion and the non-adhesive portion may be arranged in any pattern selected from a stripe shape, a lattice shape, a dot shape, a shape in which a plurality of wavy lines are arranged, a checkered pattern, and a shape in which various patterns are arranged in a plurality. Other shapes may be preferable.
  • the pattern is normally provided in the whole surface of a support body.
  • the pattern pitch (that is, the interval between adjacent adhesive portions or the interval between adjacent non-adhesive portions) is preferably 10 to 500 ⁇ m, more preferably 10 to 300 ⁇ m, particularly The thickness is preferably 10 to 250 ⁇ m. That is, the width of each stripe and the interval between stripes, the width of each wavy line and the interval between wavy lines, the width of each line forming the lattice, the interval between adjacent lines constituting the lattice, the interval between dots
  • the width and height of the dots, or the height and width of each square constituting the checkered pattern is preferably 10 to 500 ⁇ m, more preferably 10 to 300 ⁇ m, and particularly preferably 10 to 250 ⁇ m.
  • the surface protective film may be cured in advance by irradiating a part of the pressure-sensitive adhesive layer with energy rays before adhering to the surface of the adherend.
  • the adhesive surface that adheres to the surface of the adherend of the surface protective film is strongly adhered to the surface without being irradiated with energy rays.
  • Part and an energy ray are irradiated and hardened
  • the strong adhesive portion and the weak adhesive portion are preferably arranged in a pattern like the above-described adhesive portion and non-adhesive portion.
  • the partial curing of the pressure-sensitive adhesive layer is not particularly limited, but for example, it is publicly known through a mask having an opening having a shape matching the weakly-adhesive part or a light-shielding member having a light-shielding part having a shape corresponding to the strong adhesive part. It is good to carry out by irradiating an adhesive layer with an energy ray from an irradiation apparatus.
  • the energy ray may be applied to the pressure-sensitive adhesive layer from the support side through the support, or may be applied from the opposite side of the support.
  • the surface protective film attached to the adherend is applied to the surface protective film. It is preferable to irradiate energy rays. Adhesive part and non-adhesive part or strong adhesive part and weak adhesive part are provided on the surface protective film, and the ratio of the area of the adhesive part and non-adhesive part, or the ratio of the area of strong adhesive part and weak adhesive part is adjusted appropriately By doing so, the adhesive force of the surface protective film can be appropriately adjusted.
  • the said support body may have an easily bonding layer between a base material and a buffer layer, between a base material and a resin layer, or both in order to improve the adhesiveness between the layers of each layer.
  • the surface is in contact with the surface of the pressure-sensitive adhesive layer (if the support has a resin layer or a substrate, any surface thereof). May have an easy-adhesion layer.
  • a composition for easy-adhesion layer formation which forms an easy-adhesion layer,
  • the easy-adhesion layer-forming composition contains a crosslinking agent, a photopolymerization initiator, an antioxidant, a softening agent (plasticizer), a filler, a rust inhibitor, a pigment, a dye, and the like as necessary. May be.
  • the thickness of the easy adhesion layer is preferably 0.01 to 10 ⁇ m, more preferably 0.03 to 5 ⁇ m.
  • the pressure-sensitive adhesive layer side of the surface protective film of the present invention may be protected with a release sheet by attaching a release sheet.
  • a release sheet that has been subjected to a double-sided release treatment, a release sheet that has been subjected to a single-sided release treatment, or the like is used.
  • a resin film is preferable, and examples of the resin constituting the resin film include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, polypropylene resin, polyethylene resin, and the like. Polyolefin resin and the like.
  • the release agent examples include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long chain alkyl resins, alkyd resins, and fluorine resins.
  • the thickness of the release sheet is not particularly limited, but is preferably 10 to 200 ⁇ m, more preferably 20 to 150 ⁇ m.
  • the film area of the surface protective film is preferably 100 mm 2 or less, more preferably about 10 to 80 mm 2 .
  • a surface protection film becomes small according to an optical member and an electronic member. Generally, when the film size is reduced, operations such as pasting and peeling become difficult. Since the surface protective film of the present invention has good peeling performance as described above, it is easy to peel off even by manual work.
  • the shape of the surface protective film is not limited, but is processed into, for example, a circular shape, an annular shape, a square shape, a rectangular shape, or the like. In addition, when processing a surface protection film into a predetermined film area thru
  • ⁇ Method for producing surface protective film> There is no restriction
  • the buffer layer provided on the release sheet and the pressure-sensitive adhesive layer provided on the release sheet can be bonded to each side of the substrate.
  • a buffer layer can be provided directly on the surface of the substrate to produce a support, and the pressure-sensitive adhesive layer can be provided on the support.
  • the buffer layer provided on the release sheet and the pressure-sensitive adhesive layer provided on the release sheet may be bonded to each other.
  • a coating film can be formed by directly applying the buffer layer forming composition on the release sheet or substrate by a known application method. Moreover, a buffer layer can be formed by drying a coating film and / or irradiating energy rays. Examples of the coating method include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.
  • an organic solvent may be mix
  • the organic solvent to be used include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol and the like.
  • combination of each component contained in a composition may be used as it is, and 1 or more types of other organic solvents may be added.
  • the coating film is cured by irradiating energy rays to the buffer layer.
  • the buffer layer may be cured completely at once, or may be cured in multiple steps.
  • the coating film on the release sheet is completely cured to form a buffer layer, it may be bonded to the base material, and a semi-cured buffer layer forming film is formed without completely curing the coating film.
  • the buffer layer may be formed by irradiating energy rays again to be completely cured.
  • the buffer layer may be formed by irradiating energy rays again and completely curing Good.
  • an ultraviolet-ray is preferable as an energy ray irradiated by the said hardening process.
  • the irradiation amount of energy rays is appropriately changed depending on the type of energy rays.
  • the illuminance of the irradiated ultraviolet rays is preferably 50 to 500 mW / cm 2 , more preferably 100 to 340 mW / cm 2
  • the irradiation amount of ultraviolet rays is preferably 80 to 2500 mJ / cm 2 , More preferably, it is 100 to 2000 mJ / cm 2 .
  • a buffer layer when using the resin film for buffer layers as a buffer layer, a buffer layer can be formed using a general extrusion laminating process other than said coating method. Moreover, the resin film for buffer layers shape
  • the method for forming the pressure-sensitive adhesive layer is not particularly limited, but an energy ray-curable pressure-sensitive adhesive composition diluted with an appropriate solvent as necessary is applied on the release sheet so as to have a predetermined dry film thickness, and thereafter After drying to form a pressure-sensitive adhesive layer, a base material or a support may be bonded to the pressure-sensitive adhesive layer. Moreover, the energy ray-curable pressure-sensitive adhesive composition diluted with an appropriate solvent as required may be directly applied to a substrate or a support and then dried to form a pressure-sensitive adhesive layer.
  • the process (punching process) which uses a punching blade may be mainly performed.
  • the punching blade is usually inserted from the surface opposite to the surface on which the pressure-sensitive adhesive layer of the support is provided (that is, the surface on which the buffer layer is provided).
  • the surface protective film of the present invention since the buffer layer is present on the surface of the surface protective film on the side where the punching blade is applied, slippage of the punching blade that occurs during the punching process can be suppressed, and processing accuracy is improved.
  • the punching process may be performed on a laminate of the pressure-sensitive adhesive layer and the support formed on the release sheet.
  • the shape of the surface protection film is changed to a predetermined shape such as a circle as described above.
  • an imaging module in which one or more lenses and an imaging sensor such as a CCD or CMOS are housed in a casing or a package; a plurality of lenses is a lens mirror Examples include a lens unit held in a tube and housed in a housing or a package as necessary; a light emitting element unit having a light emitting element such as an LED; a motor unit such as a vibrator; a communication module, a sensor module, and the like.
  • These optical members and electronic members are preferably members that are used by being attached to other members such as a substrate.
  • the optical member refers to an optical component that receives or emits light, or includes an optical component that transmits light.
  • an imaging module, a lens unit, a light emitting element unit, a communication module that transmits or receives an optical signal An example of the optical member is an optical sensor module.
  • the electronic member usually includes at least a part of an electric circuit and includes an electronic component that transmits or receives an electric signal, an electronic component that processes an electric signal, an electronic component that operates by an electric signal or electric power, and the like.
  • a motor unit such as an imaging module, a light emitting element unit, and a vibrator, a communication module that transmits or receives an electrical signal, various sensor modules, and the like are specific examples of the electronic member.
  • a communication module, an optical sensor module, an imaging module, a light emitting element unit, and the like that transmit or receive optical signals are members that are both electronic members and optical members.
  • the optical member or the electronic member is, for example, one in which the electronic component or the optical component is housed in a package or a housing or supported by a support member.
  • a part of electronic component or optical component is exposed on the surface, and the surface protection film is used, for example, to protect the exposed component.
  • the surface protective film of this invention is used in order to stick on the surface of an optical member or an electronic member, and to protect the surface.
  • an optical member or an electronic member (hereinafter also simply referred to as a member with a surface protective film) to which a surface protective film is attached is processed, attached to another member, inspected, transported, or the like.
  • the surface protective film protects the surface of the optical member or the electronic member in these steps.
  • the surface protective film is peeled off from the optical member or the electronic member after being irradiated with energy rays and reducing the adhesive force when these steps are finished and the surface protection is no longer necessary.
  • sticking and peeling of a surface protection film are normally performed manually.
  • the surface protective film of the present invention since it is difficult to cause a shift in the attaching position when attaching to the surface of the optical member or the electronic member, so that the frequency of reattaching is reduced.
  • the surface protective film once pasted can be peeled off without applying an excessive load even when peeled off from the adherend, it damages the optical member or electronic member that is the adherend (distortion is distorted). Can be prevented.
  • the member with a surface protective film may be heated in steps such as the above-described processing, attachment, inspection, or conveyance.
  • the heating temperature at that time is not particularly limited, but is about 60 to 200 ° C., preferably about 70 to 150 ° C.
  • the pressure-sensitive adhesive layer may become highly adhesive when heated.
  • the energy ray-curable pressure-sensitive adhesive composition is used for the pressure-sensitive adhesive layer of the surface protective film of the present invention, even if the pressure-sensitive adhesive force is increased by heating, the pressure-sensitive adhesive force is reduced by irradiating energy rays thereafter. Therefore, it is difficult for peeling failure or adhesive residue to occur when the surface protective film is peeled off.
  • the optical member or the electronic member (the member with the surface protective film) to which the surface protective film is attached is attached to another member such as a substrate with an adhesive, for example.
  • a thermosetting adhesive is used, and in order to cure the adhesive, the member with a surface protective film is usually at a temperature of 60 to 200 ° C. or higher, preferably about 70 to 150 ° C. as described above. Heating is preferred.
  • the surface protection film is peeled from the optical member or the electronic member after the surface protection film is irradiated with energy rays and the adhesive force is reduced.
  • the surface protective film is particularly preferably used as a surface protective film for an imaging module in the above-described optical member or electronic member.
  • the imaging module is usually provided with a light receiving portion for receiving light from the outside on one surface and guiding the light to the imaging device via a lens inside the module.
  • the light receiving unit is provided on a part (for example, the center) of one surface of the imaging module and is made of glass or transparent resin.
  • the surface protective film is preferably attached to one surface of the imaging module where the light receiving part is provided so as to cover the light receiving part.
  • the surface protective film adheres to the surface of the light receiving unit and the casing or package around the light receiving unit with high adhesive force before irradiation with energy rays, the light receiving unit provided on one surface of the imaging module should be appropriately protected. Is possible. Moreover, since the adhesive strength of the surface protective film is reduced after irradiation with energy rays, the surface protective film can be easily peeled off from the imaging module, and it is possible to prevent adhesive residue from being generated in the light receiving portion and the like. In addition, as above-mentioned, it is preferable that the imaging module with which the surface protective film was stuck is heated for hardening of a thermosetting adhesive, and is attached to other members, such as a board
  • the measurement method and evaluation method in the present invention are as follows.
  • Measuring device Product name “HLC-8220GPC”, manufactured by Tosoh Corporation)
  • Column Product name “TSKGel SuperHZM-M” manufactured by Tosoh Corporation)
  • Developing solvent Tetrahydrofuran
  • Column temperature 40 ° C
  • Flow rate 1.0 mL / min ⁇ Bending softness of support> Measurements were performed in the MD direction and TD direction of the support by a method according to JIS L 1913. However, a 45 ° cantilever type tester was used, and the support was cut into 20 mm ⁇ 150 mm test pieces. Two test pieces used for the measurement were prepared in each of the MD direction and the TD direction.
  • the test piece in the MD direction means that the longitudinal direction of the test piece is the MD direction of the support.
  • the bending length (mN ⁇ cm) was measured four times in total, twice on the front surface (both ends) and twice on the back surface (both ends). The average value was calculated for the measurement results for the four times.
  • the same measurement was performed for the TD direction. From the measured value of the bending length of two test pieces in the MD direction and the mass per unit area (g / m 2 ) of the test piece used for the measurement, the calculation formula described in JIS L 1913 is used. MD bending resistance was calculated. Similarly, in the TD direction, the TD bending resistance was calculated using the measurement values of the bending lengths of two test pieces.
  • the indentation depth (Z) was measured when the compression load reached 2 mN.
  • This surface protective film was peeled off from the release sheet using tweezers, and was bonded to an imaging module as an adherend. Moreover, the surface protection film was peeled off from the imaging module using tweezers after UV irradiation, and the workability was evaluated according to the following criteria.
  • B Although time was required for peeling from the release sheet and time was required for bonding to the imaging module, peeling after UV irradiation was easily performed.
  • C The film could be easily peeled off from the release sheet, and could be easily attached to the imaging module without any mistake, but it took time to peel off after UV irradiation.
  • Example 1 Preparation of composition for forming buffer layer 40 parts by mass of the urethane acrylate oligomer (UA-1) synthesized in Production Example 1 so that the total amount of the energy ray polymerizable compound is 100 parts by mass (solid content ratio). 40 parts by mass of isobornyl acrylate (IBXA) and 20 parts by mass of phenylhydroxypropyl acrylate (HPPA) were blended, and 1-hydroxycyclohexyl phenyl ketone (product name “Irgacure 184” manufactured by BASF) was used as a photopolymerization initiator. 2.0 parts by mass and 0.2 parts by mass of a phthalocyanine pigment were blended to prepare a composition for forming a buffer layer.
  • IBXA isobornyl acrylate
  • HPPA phenylhydroxypropyl acrylate
  • 1-hydroxycyclohexyl phenyl ketone product name “Irgacure 184” manufactured by BASF
  • the above ultraviolet irradiation uses a belt conveyor type ultraviolet irradiation device (product name “ECS-401GX”, manufactured by I-Graphics) and a high-pressure mercury lamp (H04-L41 manufactured by I-Graphics: H04-L41).
  • ECS-401GX belt conveyor type ultraviolet irradiation device
  • H04-L41 high-pressure mercury lamp
  • the measurement was performed under irradiation conditions of a height of 150 mm, a lamp output of 3 kW (converted output of 120 mW / cm), an illuminance of 120 mW / cm 2 with a light wavelength of 365 nm, and an irradiation amount of 100 mJ / cm 2 .
  • the surface of the formed buffer layer forming film and a release sheet (trade name “SP-PET 381031” manufactured by Lintec Co., Ltd., polyethylene terephthalate (PET) film subjected to silicone release treatment, thickness: 38 ⁇ m) are released.
  • the peeled surface was bonded, and ultraviolet rays were irradiated again from the release sheet side on the buffer layer forming film to completely cure the buffer layer forming film, thereby forming a buffer layer having a thickness of 20 ⁇ m.
  • said ultraviolet irradiation uses the above-mentioned ultraviolet irradiation apparatus and a high pressure mercury lamp, lamp
  • Example 2 A surface protective film was produced in the same manner as in Example 1 except that the thickness of the buffer layer was 50 ⁇ m.
  • Example 3 Similar to Example 1 except that a support having a thickness of 75 ⁇ m and a low-density polyethylene film (buffer layer) having a thickness of 25 ⁇ m bonded to the same base material as in Example 1 with an epoxy resin adhesive was used. Thus, a surface protective film was produced.
  • Example 4 A support having a thickness of 100 ⁇ m was prepared by laminating a low-density polyethylene film (buffer layer and resin layer) having a thickness of 25 ⁇ m with an epoxy resin adhesive on both surfaces of the same substrate as in Example 1. A pressure-sensitive adhesive layer having a thickness of 20 ⁇ m was formed on the resin layer surface in the same manner as in Example 1 to produce a surface protective film.
  • Example 5 A surface protective film was produced in the same manner as in Example 1 except that a polyethylene terephthalate film (trade name: Cosmo Shine, product number: A-4100, manufactured by Toyobo Co., Ltd.) having a thickness of 100 ⁇ m was used as the substrate.
  • a polyethylene terephthalate film (trade name: Cosmo Shine, product number: A-4100, manufactured by Toyobo Co., Ltd.) having a thickness of 100 ⁇ m was used as the substrate.
  • Example 1 A surface protective film was produced in the same manner as in Example 1 except that the buffer layer was not formed.
  • Example 2 A surface protective film was produced in the same manner as in Example 1 except that a low-density polyethylene film having a thickness of 80 ⁇ m was used as the substrate.
  • Example 3 A surface protective film was produced in the same manner as in Example 1 except that a low-density polyethylene film having a thickness of 50 ⁇ m was used as the substrate and the thickness of the buffer layer was changed to 50 ⁇ m.
  • Example 4 A surface protective film was produced in the same manner as in Example 1, except that a polyethylene terephthalate film (trade name: Cosmo Shine, product number: A-4100, manufactured by Toyobo Co., Ltd.) having a thickness of 125 ⁇ m was used as the substrate.
  • a polyethylene terephthalate film (trade name: Cosmo Shine, product number: A-4100, manufactured by Toyobo Co., Ltd.) having a thickness of 125 ⁇ m was used as the substrate.
  • the surface protective films prepared in Examples 1 to 5 are both excellent in workability and workability.
  • the surface protective film produced in Comparative Example 1 has excellent workability because the support has good bending resistance, but has no buffer layer, has a shallow depth of pushing into the base material, and has good workability. It became inferior result.
  • the workability was inferior due to the low bending resistance of the support, and in Comparative Example 4, the workability was inferior because the bending resistance of the support was too high. .
  • the surface protective film of the present invention is excellent in workability and workability. Therefore, the surface protective film of the present invention can be suitably used as, for example, a surface protective film that protects the surface of an optical member or an electronic member. It is possible to effectively prevent a reduction in the frequency of reattachment due to the improvement of the sticking property and damage to the adherend during peeling.

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Abstract

This surface protective film is affixed to an optical member or an electronic member and is used to protect the surface of the optical member or the electronic member, wherein: the surface protective film is provided with a support body having a bending resistance of 5,000-45,000 mN·cm, and an adhesive layer on one surface of the support body; the support body has a buffer layer comprising one or more materials selected from buffer layer formation resin films and buffer layer formation compositions containing an energy-beam-polymerizable compound; and when the buffer layer is indented by the tip of a triangular-pyramid-shaped indenter having a tip curvature radius of 100 nm and an inter-ridge angle of 115° at a speed of 10 μm/min, the indentation depth (Z) required for the compression load to reach 2 mN is 2.5 μm or above.

Description

表面保護フィルムSurface protection film
　本発明は、支持体の一方の面に粘着剤が積層されてなる表面保護フィルムに関し、特に、各種の光学部材や電子部材の表面に貼付されて、その表面を保護するために使用される表面保護フィルムに関する。 The present invention relates to a surface protective film in which a pressure-sensitive adhesive is laminated on one surface of a support, and in particular, a surface that is applied to the surface of various optical members and electronic members and used to protect the surface. It relates to a protective film.
　従来、カメラのレンズユニット、通信・センサーモジュール、バイブレーター等のモーターユニット、撮像モジュール等、例えばユニット化した光学部材や電子部材は、加工、組立、検査、輸送などの際、表面の傷付きを防止するために、露出面に表面保護フィルムが貼着されることがある。表面保護フィルムは、表面保護の必要がなくなった時点で、光学部材や電子部材から剥離される。 Conventionally, camera lens units, communication / sensor modules, motor units such as vibrators, imaging modules, etc., such as unitized optical and electronic components, prevent surface damage during processing, assembly, inspection, transportation, etc. In order to do this, a surface protective film may be stuck on the exposed surface. The surface protective film is peeled off from the optical member or the electronic member when the surface protection is no longer necessary.
　また、このような表面保護フィルムの基材としては、例えば、透明性を得る観点からポリエチレンテレフタレートフィルムを、また耐熱性といった観点から、ポリイミドやポリエチレンナフタレートといった基材を使用することが知られている（特許文献１参照）。 Moreover, as a base material of such a surface protective film, for example, it is known to use a polyethylene terephthalate film from the viewpoint of obtaining transparency and a base material such as polyimide or polyethylene naphthalate from the viewpoint of heat resistance. (See Patent Document 1).
特開２００５－３４１５２０号公報JP 2005-341520 A
　近年、上記したような光学部材や電子部材は、小型化が進んでおり、それに伴い表面保護フィルムのサイズも小さくなってきている。そのため、抜き刃を使用して表面保護フィルムを適切なサイズに加工することが難しくなってきている。従って、表面保護フィルムの加工精度向上に対する要求が高まりつつある。
　また、表面保護フィルムの貼り付け及び剥離は、通常、手作業で行われるため、貼り付け及び剥離の作業性を良好にすることが求められる。具体的には、フィルムが小サイズであるため、貼り付け時に位置ずれが生じやすく、貼り直しの頻度が高くなってしまう。貼り直しの頻度を低減するため、貼り付け易さの向上が要求されるようになってきている。また、被着体から表面保護フィルムが剥離しにくいと、被着体である光学部材や電子部材に過度な負荷がかかり、デリケートな該部材を痛めてしまう（歪を起こす、傷が付く等）可能性がある。そのため、表面保護フィルムの剥離性能も良好にすることが求められている。
　しかしながら、例えば特許文献１では、このような表面保護フィルムの抜き加工性や貼り付け及び剥離といった作業性についての検討はされていない。 In recent years, optical members and electronic members as described above have been reduced in size, and the size of the surface protection film has been reduced accordingly. Therefore, it has become difficult to process the surface protective film into an appropriate size using a punching blade. Therefore, the demand for improving the processing accuracy of the surface protective film is increasing.
Moreover, since attachment and peeling of a surface protective film are normally performed manually, it is calculated | required that workability | operativity of attachment and peeling is made favorable. Specifically, since the film is small in size, misalignment is likely to occur at the time of attachment, and the frequency of reattachment is increased. In order to reduce the frequency of re-sticking, improvement in the ease of sticking has been demanded. In addition, if the surface protective film is difficult to peel from the adherend, an excessive load is applied to the optical member or electronic member that is the adherend, and the delicate member is damaged (distortion, scratches, etc.). there is a possibility. Therefore, it is required to improve the peeling performance of the surface protective film.
However, for example, Patent Document 1 does not discuss workability such as punching process, pasting, and peeling of the surface protective film.
　本発明は、以上の問題点に鑑みてなされたものであり、本発明の課題は、表面保護フィルムの抜き加工性、並びに貼り付け及び剥離時の作業性に優れた、光学部材又は電子部材用の表面保護フィルムを提供することである。 This invention is made | formed in view of the above problem, and the subject of this invention is the optical member or the electronic member excellent in the workability | operativity at the time of the processability at the time of sticking and peeling, and a surface protection film It is to provide a surface protective film.
　本発明者らは、鋭意検討の結果、表面保護フィルムが特定の剛軟度を有する支持体を有し、かつ該支持体が、所定の形状の圧子を押し込んだ際の圧縮荷重が２ｍＮに到達するのに必要な押し込み深さが所定値以上である緩衝層を有することによって、上記課題を解決し得ることを見出し、本発明を完成させた。
　すなわち、本発明は、下記〔１〕～〔１２〕を提供するものである。
〔１〕光学部材又は電子部材に貼付し、その表面を保護するために使用される表面保護フィルムであって、
　剛軟度が５０００ｍＮ・ｃｍ以上、４５０００ｍＮ・ｃｍ以下である支持体と、該支持体の一方の面に粘着剤層とを備え、
　該支持体が、エネルギー線重合性化合物を含む緩衝層形成用組成物及び緩衝層形成用樹脂フィルムから選ばれる１種以上からなる緩衝層を有し、先端曲率半径１００ｎｍ及び稜間角１１５°の三角錘形状圧子の先端を１０μｍ／分の速度で、該緩衝層に押し込んだ際の圧縮荷重が２ｍＮに到達するのに必要な押し込み深さ（Ｚ）が２．５μｍ以上である、表面保護フィルム。
〔２〕前記支持体が、さらに基材を有する、上記〔１〕に記載の表面保護フィルム。
〔３〕前記支持体が、前記基材の緩衝層が設けられる面と反対側の面に更に樹脂層を有する支持体である、上記〔２〕に記載の表面保護フィルム。
〔４〕前記緩衝層が、前記粘着剤層と反対側の面に表出している、上記〔１〕～〔３〕のいずれかに記載の表面保護フィルム。
〔５〕前記基材が、ポリエチレンテレフタレートからなる樹脂フィルムである、上記〔２〕～〔４〕のいずれかに記載の表面保護フィルム。
〔６〕前記緩衝層形成用組成物が、前記エネルギー線重合性化合物として、ウレタン（メタ）アクリレート（ａ１）、環形成原子数６～２０の脂環基又は複素環基を有する重合性化合物（ａ２）、及び官能基を有する重合性化合物（ａ３）を含む、上記〔１〕～〔５〕のいずれかに記載の表面保護フィルム。
〔７〕前記緩衝層形成用樹脂フィルムが、ポリエチレンフィルムである、上記〔１〕～〔６〕のいずれかに記載の表面保護フィルム。
〔８〕前記緩衝層の厚さが５～１００μｍである、上記〔１〕～〔７〕のいずれかに記載の表面保護フィルム。
〔９〕前記粘着剤層が、エネルギー線硬化型粘着剤組成物からなる、上記〔１〕～〔８〕のいずれかに記載の表面保護フィルム。
〔１０〕前記粘着剤層が、アクリル系共重合体を含むエネルギー線硬化型粘着剤組成物からなり、
　該アクリル系共重合体が、少なくともアルキル基の炭素数が１又は２であるアルキル（メタ）アクリレートを５～５０質量％含むとともに、カルボキシル基含有モノマーを含まず又は５質量％未満含むモノマー成分を共重合体したものである、上記〔１〕～〔９〕のいずれかに記載の表面保護フィルム。
〔１１〕光学部材又は電子部材と、該光学部材又は該電子部材の表面に貼付される上記〔１〕～〔１０〕のいずれかに記載の表面保護フィルムとを備える表面保護フィルム付き部材。
〔１２〕上記〔１〕～〔１０〕のいずれかに記載の表面保護フィルムを、光学部材又は電子部材の表面に貼付して該表面を保護する方法。 As a result of intensive studies, the inventors of the present invention have a support body in which the surface protective film has a specific bending resistance, and the support body reaches a compression load of 2 mN when an indenter having a predetermined shape is pushed in. The present inventors have found that the above-mentioned problems can be solved by having a buffer layer having a pressing depth required to achieve a predetermined value or more, and the present invention has been completed.
That is, the present invention provides the following [1] to [12].
[1] A surface protective film that is applied to an optical member or an electronic member and used to protect the surface thereof,
Comprising a support having a bending resistance of 5000 mN · cm or more and 45000 mN · cm or less, and an adhesive layer on one surface of the support,
The support has a buffer layer composed of at least one selected from a buffer layer-forming composition containing an energy beam polymerizable compound and a buffer layer-forming resin film, and has a tip curvature radius of 100 nm and a ridge angle of 115 °. Surface protective film having a pressing depth (Z) of 2.5 μm or more required to reach a compression load of 2 mN when the tip of the triangular pyramid-shaped indenter is pressed into the buffer layer at a speed of 10 μm / min. .
[2] The surface protective film according to [1], wherein the support further has a base material.
[3] The surface protective film according to the above [2], wherein the support is a support further having a resin layer on a surface opposite to the surface on which the buffer layer of the substrate is provided.
[4] The surface protective film according to any one of [1] to [3], wherein the buffer layer is exposed on a surface opposite to the pressure-sensitive adhesive layer.
[5] The surface protective film according to any one of [2] to [4], wherein the substrate is a resin film made of polyethylene terephthalate.
[6] The composition for forming a buffer layer is a polymerizable compound having urethane (meth) acrylate (a1), an alicyclic group having 6 to 20 ring atoms or a heterocyclic group as the energy ray polymerizable compound ( The surface protective film according to any one of [1] to [5] above, comprising a2) and a polymerizable compound (a3) having a functional group.
[7] The surface protective film according to any one of [1] to [6], wherein the buffer layer forming resin film is a polyethylene film.
[8] The surface protective film according to any one of [1] to [7] above, wherein the buffer layer has a thickness of 5 to 100 μm.
[9] The surface protective film according to any one of [1] to [8], wherein the pressure-sensitive adhesive layer is made of an energy ray-curable pressure-sensitive adhesive composition.
[10] The pressure-sensitive adhesive layer comprises an energy ray-curable pressure-sensitive adhesive composition containing an acrylic copolymer,
The acrylic copolymer contains a monomer component containing at least 5 to 50% by mass of an alkyl (meth) acrylate having an alkyl group having 1 or 2 carbon atoms and not containing a carboxyl group-containing monomer or less than 5% by mass. The surface protective film according to any one of [1] to [9] above, which is a copolymer.
[11] A member with a surface protective film, comprising: an optical member or an electronic member; and the surface protective film according to any one of the above [1] to [10] attached to a surface of the optical member or the electronic member.
[12] A method of protecting the surface by applying the surface protective film according to any one of [1] to [10] to the surface of an optical member or an electronic member.
　本発明では、表面保護フィルムの抜き加工性、並びに貼り付け及び剥離時の作業性に優れた、光学部材又は電子部材用の表面保護フィルムを提供することが可能である。 In the present invention, it is possible to provide a surface protective film for an optical member or an electronic member that is excellent in the processability of the surface protective film and the workability at the time of pasting and peeling.
　本明細書中の記載において、「エネルギー線」とは、例えば、紫外線、電子線等を意味し、紫外線又は電子線が好ましい。
　また、本明細書中の記載において、「重量平均分子量（Ｍｗ）」とは、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）法で測定される標準ポリスチレン換算の値であり、具体的には実施例に記載の方法に基づいて測定した値である。
　加えて、本明細書中の記載において、例えば、「（メタ）アクリレート」とは、「アクリレート」と「メタクリレート」の双方を意味する語であり、他の類似用語も同様である。 In the description of the present specification, the “energy beam” means, for example, an ultraviolet ray or an electron beam, and an ultraviolet ray or an electron beam is preferable.
In the description of the present specification, the “weight average molecular weight (Mw)” is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method, and specifically described in the examples. It is a value measured based on the method.
In addition, in the description in the present specification, for example, “(meth) acrylate” means both “acrylate” and “methacrylate”, and other similar terms are also the same.
［表面保護フィルム］
　本発明の表面保護フィルムは、光学部材又は電子部材に貼付し、その表面を保護するために使用されるものであって、支持体と、支持体の一方の面に設けられた粘着剤層とを備える。
　以下、表面保護フィルムの各部材について説明する。 [Surface protection film]
The surface protective film of the present invention is used for affixing to an optical member or an electronic member and protecting the surface thereof, and a support and a pressure-sensitive adhesive layer provided on one surface of the support. Is provided.
Hereinafter, each member of the surface protective film will be described.
＜支持体＞
　本発明の表面保護フィルムが有する支持体は、緩衝層を有する支持体であって、剛軟度が５０００ｍＮ・ｃｍ以上、４５０００ｍＮ・ｃｍ以下である。
　剛軟度が５０００ｍＮ・ｃｍ未満の支持体を用いた場合、得られる表面保護フィルムを光学部材又は電子部材表面に貼付する際に、当該表面保護フィルムのコシが弱いため、目標の貼付位置へ貼付し難くなり作業性が劣る。
　また、剛軟度が４５０００ｍＮ・ｃｍを超える支持体を用いた場合、光学部材又は電子部材表面に貼付した表面保護フィルムを当該部材表面から剥がす際に、当該表面保護フィルムのコシが強すぎるため、剥がし難くなり作業性が劣る。さらには、剥がす際に必要以上の負荷が光学部材又は電子部材に対してかかることにより、当該部材にダメージを与えてしまう可能性がある。
　特に、手作業による貼付及び剥離作業時は、指やピンセット等の道具を用いて小サイズの表面保護フィルムを取り扱うため、上述した作業が、よりいっそう困難となる。
　このような観点から、当該支持体の剛軟度は、好ましくは５５００ｍＮ・ｃｍ以上、より好ましくは６０００ｍＮ・ｃｍ以上であり、また、好ましくは４２５００ｍＮ・ｃｍ以下、より好ましくは４００００ｍＮ・ｃｍ以下である。なお、剛軟度は、ＪＩＳ　Ｌ　１９１３に準ずる方法で測定され、具体的には実施例に記載された方法で測定、算出された値である。
　また、支持体の厚さは、上記支持体の剛軟度が上記範囲であれば特に制限はされないが、本発明の表面保護フィルムを光学部材又は電子部材に貼り付け及び剥離する際の作業性を良好とする観点から、好ましくは３０～２００μｍ、より好ましくは４０～２００μｍ、更に好ましくは５０～１５０μｍである。 <Support>
The support body which the surface protective film of this invention has is a support body which has a buffer layer, Comprising: The bending resistance is 5000 mN * cm or more and 45000 mN * cm or less.
When a support having a bending resistance of less than 5000 mN · cm is used, when the obtained surface protective film is applied to the surface of an optical member or an electronic member, the surface protective film is not strong enough to be applied to the target application position. It becomes difficult to work and the workability is inferior.
In addition, when using a support having a bending resistance exceeding 45000 mN · cm, when the surface protection film attached to the optical member or electronic member surface is peeled off from the surface of the member, the stiffness of the surface protection film is too strong. It becomes difficult to peel off and workability is inferior. Furthermore, when an unnecessary load is applied to the optical member or the electronic member when peeling off, the member may be damaged.
In particular, at the time of manual sticking and peeling work, the above-described work becomes even more difficult because a small-sized surface protective film is handled using a tool such as a finger or tweezers.
From such a viewpoint, the bending resistance of the support is preferably 5500 mN · cm or more, more preferably 6000 mN · cm or more, and preferably 42500 mN · cm or less, more preferably 40000 mN · cm or less. . The bending resistance is a value measured and calculated by a method according to JIS L 1913, specifically, a method described in the examples.
Further, the thickness of the support is not particularly limited as long as the bending resistance of the support is in the above range, but workability when the surface protective film of the present invention is attached to and peeled off from an optical member or an electronic member. From the viewpoint of improving the thickness, it is preferably 30 to 200 μm, more preferably 40 to 200 μm, still more preferably 50 to 150 μm.
（緩衝層）
　上記支持体が有する緩衝層は、先端曲率半径１００ｎｍ及び稜間角１１５°の三角錘形状圧子の先端を１０μｍ／分の速度で、当該緩衝層に押し込んだ際の圧縮荷重が２ｍＮに到達するのに必要な押し込み深さ（Ｚ）（以下、単に「押し込み深さ（Ｚ）」ともいう）が２．５μｍ以上である。
　緩衝層は、エネルギー線重合性化合物を含む緩衝層形成用組成物及び緩衝層形成用樹脂フィルムから選ばれる１種以上からなる層であり、エネルギー線重合性化合物を含む緩衝層形成用組成物の組成の選択又は緩衝層形成用樹脂フィルムの選択によって緩衝層の押し込み深さ（Ｚ）を調整することが比較的容易である。
　また、緩衝層は、押し込み深さを大きくしやすいため、エネルギー線重合性化合物を含む緩衝層形成用組成物から選ばれる１種以上からなる層であることが好ましい。 (Buffer layer)
The buffer layer of the support has a compressive load of 2 mN when the tip of a triangular pyramid-shaped indenter having a tip radius of curvature of 100 nm and a ridge angle of 115 ° is pushed into the buffer layer at a speed of 10 μm / min. The indentation depth (Z) (hereinafter also simply referred to as “indentation depth (Z)”) required for the above is 2.5 μm or more.
The buffer layer is a layer composed of at least one selected from a buffer layer forming composition containing an energy ray polymerizable compound and a buffer layer forming resin film, and is a buffer layer forming composition containing an energy ray polymerizable compound. It is relatively easy to adjust the indentation depth (Z) of the buffer layer by selecting the composition or selecting the resin film for forming the buffer layer.
Moreover, since a buffer layer is easy to enlarge indentation depth, it is preferable that it is a layer which consists of 1 or more types chosen from the composition for buffer layer formation containing an energy-beam polymeric compound.
　また、本発明者らは、表面保護フィルムの構成において、上記の押し込み深さ（Ｚ）を２．５μｍ以上となるように調整された緩衝層を加工時に抜き刃と接する位置に設けることで、表面保護フィルムの抜き加工精度を向上させ、表面保護フィルムのサイズを正確に制御し得ることを見出した。
　当該押し込み深さ（Ｚ）が２．５μｍ未満である緩衝層を有する表面保護フィルムの場合、緩衝層が硬くなり過ぎて、抜き加工時に抜き刃が入り難くなる、又は抜き刃に対して表面保護フィルムが滑りやすくなるなどして、抜き加工後の表面保護フィルムのサイズを正確に制御することが難しい。
　一方、当該押し込み深さ（Ｚ）が３０μｍ以下である緩衝層を有する表面保護フィルムの場合、緩衝層が過度に軟らかくなり過ぎないため、抜き加工時にも抜き刃に緩衝層が貼り付かず、また、抜き刃が接触する際に緩衝層が変形して表面保護フィルムが位置ずれしてしまうことがないため、抜き加工後の表面保護フィルムのサイズを正確に制御しやすくなる。
　このような観点から、上記の押し込み深さ（Ｚ）は、好ましくは２．５～３０．０μｍ、より好ましくは５．０～２５．０μｍ、更に好ましくは８．０～２０．０μｍ、より更に好ましくは１２．０～２０．０μｍである。
　なお、本発明において、当該押し込み深さ（Ｚ）は、実施例に記載の方法により測定された値を意味する。
　また、当該押し込み深さ（Ｚ）は、緩衝層を形成するエネルギー線重合性化合物を含む緩衝層形成用組成物中に含まれる成分の種類や含有量、緩衝層の硬化の程度等を適宜変えることで、上記範囲に属するように調整することが可能である。また、緩衝層を形成する緩衝層形成用樹脂フィルムの原料樹脂を適宜選択することでも、上記範囲に属するように調整することが可能である。　
　なお、本発明の表面保護フィルムは、該緩衝層が、後述する粘着剤層と反対側の面に表出していることが好ましい。 Further, the present inventors, in the configuration of the surface protection film, by providing a buffer layer adjusted so that the indentation depth (Z) is 2.5 μm or more at a position in contact with the punching blade during processing, It has been found that the punching accuracy of the surface protective film can be improved and the size of the surface protective film can be accurately controlled.
In the case of a surface protective film having a buffer layer whose indentation depth (Z) is less than 2.5 μm, the buffer layer becomes too hard, making it difficult for the punching blade to enter during the punching process, or protecting the surface against the punching blade. It is difficult to accurately control the size of the surface protective film after the punching process because the film becomes slippery.
On the other hand, in the case of a surface protective film having a buffer layer having an indentation depth (Z) of 30 μm or less, the buffer layer is not excessively soft, so that the buffer layer does not stick to the punching blade even during the punching process. Since the buffer layer is not deformed and the surface protective film is not displaced when the punching blade comes into contact, the size of the surface protective film after the punching process can be easily controlled accurately.
From such a viewpoint, the indentation depth (Z) is preferably 2.5 to 30.0 μm, more preferably 5.0 to 25.0 μm, still more preferably 8.0 to 20.0 μm, and still more. The thickness is preferably 12.0 to 20.0 μm.
In the present invention, the indentation depth (Z) means a value measured by the method described in Examples.
Further, the indentation depth (Z) appropriately changes the type and content of components contained in the composition for forming a buffer layer containing the energy beam polymerizable compound that forms the buffer layer, the degree of curing of the buffer layer, and the like. Thus, it is possible to adjust so as to belong to the above range. Moreover, it can also be adjusted to belong to the said range also by selecting suitably the raw material resin of the resin film for buffer layer formation which forms a buffer layer.
In the surface protective film of the present invention, the buffer layer is preferably exposed on the surface opposite to the adhesive layer described later.
　上記緩衝層形成用組成物中に含まれるエネルギー線重合性化合物としては、押し込み深さ（Ｚ）を上述の範囲となる緩衝層を形成できる化合物であれば特に制限はなく、例えば、光硬化性樹脂又はモノマー等を用いることができる。
　ただし、押し込み深さ（Ｚ）を上述の範囲となるように調整する観点から、エネルギー線重合性化合物として、ウレタン（メタ）アクリレート（ａ１）、環形成原子数６～２０の脂環基又は複素環基を有する重合性化合物（ａ２）、及び官能基を有する重合性化合物（ａ３）を含む緩衝層形成用組成物が好ましい。
　また、緩衝層形成用組成物は、光重合開始剤を含有することが好ましく、本発明の効果を損なわない範囲において、その他の添加剤や樹脂成分を含有してもよい。
　以下、エネルギー線重合性化合物を含む緩衝層形成用組成物中に含まれる各成分について説明する。 The energy beam polymerizable compound contained in the buffer layer forming composition is not particularly limited as long as it is a compound capable of forming a buffer layer having an indentation depth (Z) in the above range. For example, photocurable Resin or monomer can be used.
However, from the viewpoint of adjusting the indentation depth (Z) to be in the above-mentioned range, the energy ray polymerizable compound is urethane (meth) acrylate (a1), an alicyclic group having 6 to 20 ring atoms or a heterocyclic group. A composition for forming a buffer layer comprising a polymerizable compound (a2) having a cyclic group and a polymerizable compound (a3) having a functional group is preferred.
Moreover, it is preferable that the composition for buffer layer formation contains a photoinitiator, and may contain another additive and a resin component in the range which does not impair the effect of this invention.
Hereinafter, each component contained in the composition for buffer layer formation containing an energy beam polymeric compound is demonstrated.
〔ウレタン（メタ）アクリレート（ａ１）〕
　エネルギー線重合性化合物を含む緩衝層形成用組成物で用いるウレタン（メタ）アクリレート（ａ１）としては、少なくとも（メタ）アクリロイル基及びウレタン結合を有する化合物であり、エネルギー線照射により重合硬化する性質を有するものである。
　ウレタン（メタ）アクリレート（ａ１）は、オリゴマー、高分子量体、又はこれらの混合物のいずれであってもよいが、ウレタン（メタ）アクリレートオリゴマーが好ましい。 [Urethane (meth) acrylate (a1)]
The urethane (meth) acrylate (a1) used in the composition for forming a buffer layer containing an energy ray polymerizable compound is a compound having at least a (meth) acryloyl group and a urethane bond, and has a property of being polymerized and cured by irradiation with energy rays. It is what you have.
The urethane (meth) acrylate (a1) may be an oligomer, a high molecular weight product, or a mixture thereof, but a urethane (meth) acrylate oligomer is preferable.
　成分（ａ１）の重量平均分子量（Ｍｗ）は、好ましくは１，０００～１００，０００、より好ましくは２，０００～６０，０００、更に好ましくは３，０００～２０，０００である。
　また、成分（ａ１）中の（メタ）アクリロイル基数（以下、「官能基数」ともいう）としては、単官能、２官能、もしくは３官能以上でもよいが、単官能又は２官能であることが好ましい。 The weight average molecular weight (Mw) of the component (a1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, still more preferably 3,000 to 20,000.
Further, the number of (meth) acryloyl groups (hereinafter also referred to as “number of functional groups”) in the component (a1) may be monofunctional, bifunctional, or trifunctional or more, but is preferably monofunctional or bifunctional. .
　成分（ａ１）は、例えば、ポリオール化合物と、多価イソシアネート化合物とを反応させて得られる末端イソシアネートウレタンプレポリマーに、ヒドロキシル基を有する（メタ）アクリレートを反応させて得ることができる。
　なお、成分（ａ１）は、単独で又は２種以上を組み合わせて用いてもよい。 The component (a1) can be obtained, for example, by reacting a (meth) acrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound and a polyvalent isocyanate compound.
In addition, you may use a component (a1) individually or in combination of 2 or more types.
　成分（ａ１）の原料となるポリオール化合物は、ヒドロキシ基を２つ以上有する化合物であれば特に限定されない。
　具体的なポリオール化合物としては、例えば、アルキレンジオール、ポリエーテル型ポリオール、ポリエステル型ポリオール、ポリカーボネート型ポリオール等が挙げられる。
　これらの中でも、ポリエステル型ポリオールが好ましい。
　なお、ポリオール化合物としては、２官能のジオール、３官能のトリオール、４官能以上のポリオールのいずれであってもよいが、２官能のジオールが好ましく、ポリエステル型ジオールがより好ましい。 The polyol compound used as a raw material for the component (a1) is not particularly limited as long as it is a compound having two or more hydroxy groups.
Specific examples of the polyol compound include alkylene diol, polyether type polyol, polyester type polyol, and polycarbonate type polyol.
Among these, a polyester type polyol is preferable.
The polyol compound may be a bifunctional diol, a trifunctional triol, or a tetrafunctional or higher polyol, but is preferably a bifunctional diol, and more preferably a polyester type diol.
　多価イソシアネート化合物としては、例えば、テトラメチレンジイソシアネート、ヘキサメチレンジイソシアネート、トリメチルヘキサメチレンジイソシアネート等の脂肪族系ポリイソシアネート類；イソホロンジイソシアネート、ノルボルナンジイソシアネート、ジシクロヘキシルメタン－４，４’－ジイソシアネート、ジシクロヘキシルメタン－２，４’－ジイソシアネート、ω，ω’－ジイソシアネートジメチルシクロヘキサン等の脂環族系ジイソシアネート類；４，４’－ジフェニルメタンジイソシアネート、トリレンジイソシアネート、キシリレンジイソシアネート、トリジンジイソシアネート、テトラメチレンキシリレンジイソシアネート、ナフタレン－１，５－ジイソシアネート等の芳香族系ジイソシアネート類等が挙げられる。
　これらの中でも、イソホロンジイソシアネート、ヘキサメチレンジイソシアネート、キシリレンジイソシアネートが好ましい。 Examples of the polyvalent isocyanate compound include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, dicyclohexylmethane-2 , 4'-diisocyanate, ω, ω'-diisocyanate dimethylcyclohexane, etc .; 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene- And aromatic diisocyanates such as 1,5-diisocyanate.
Among these, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferable.
　上述のポリオール化合物と、多価イソシアネート化合物とを反応させて得られる末端イソシアネートウレタンプレポリマーに、ヒドロキシ基を有する（メタ）アクリレートを反応させてウレタン（メタ）アクリレート（ａ１）を得ることができる。
　ヒドロキシ基を有する（メタ）アクリレートとしては、少なくとも１分子中にヒドロキシ基及び（メタ）アクリロイル基を有する化合物であれば、特に限定されない。 Urethane (meth) acrylate (a1) can be obtained by reacting the terminal isocyanate urethane prepolymer obtained by reacting the above-described polyol compound with the polyvalent isocyanate compound with (meth) acrylate having a hydroxy group.
The (meth) acrylate having a hydroxy group is not particularly limited as long as it is a compound having a hydroxy group and a (meth) acryloyl group in at least one molecule.
　具体的なヒドロキシ基を有する（メタ）アクリレートとしては、例えば、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレート、４－ヒドロキシシクロヘキシル（メタ）アクリレート、５－ヒドロキシシクロオクチル（メタ）アクリレート、２－ヒドロキシ－３－フェニルオキシプロピル（メタ）アクリレート、ペンタエリスリトールトリ（メタ）アクリレート、ポリエチレングリコールモノ（メタ）アクリレート、ポリプロピレングリコールモノ（メタ）アクリレート等のヒドロキシアルキル（メタ）アクリレート；Ｎ－メチロール（メタ）アクリルアミド等のヒドロキシ基含有（メタ）アクリルアミド；ビニルアルコール、ビニルフェノール、ビスフェノールＡのジグリシジルエステルに（メタ）アクリル酸を反応させて得られる反応物等が挙げられる。
　これらの中でも、ヒドロキシアルキル（メタ）アクリレートが好ましく、２－ヒドロキシエチル（メタ）アクリレートがより好ましい。 Specific examples of the (meth) acrylate having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 4-hydroxycyclohexyl (meth). Acrylate, 5-hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, etc. Hydroxy-alkyl (meth) acrylates; hydroxy-group-containing (meth) acrylamides such as N-methylol (meth) acrylamide; vinyl alcohol, vinyl phenol, bisphenol The reaction product obtained by the diglycidyl ester of Nord A (meth) acrylic acid is reacted, and the like.
Among these, hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.
　末端イソシアネートウレタンプレポリマー及びヒドロキシ基を有する（メタ）アクリレートを反応させる条件としては、必要に応じて添加される溶剤、触媒の存在下、６０～１００℃で、１～４時間反応させる条件が好ましい。 The conditions for reacting the terminal isocyanate urethane prepolymer and the (meth) acrylate having a hydroxy group are preferably the conditions of reacting at 60 to 100 ° C. for 1 to 4 hours in the presence of a solvent and a catalyst added as necessary. .
　エネルギー線重合性化合物を含む緩衝層形成用組成物中の成分（ａ１）の含有量は、押し込み深さ（Ｚ）が上述の範囲となる緩衝層を形成する観点から、緩衝層形成用組成物の全量（１００質量％）に対して、好ましくは１０～７０質量％、より好ましくは２０～６０質量％、更に好ましくは２５～５５質量％、より更に好ましくは３０～５０質量％である。 The content of the component (a1) in the composition for forming a buffer layer containing the energy beam polymerizable compound is such that the indentation depth (Z) forms a buffer layer having the above-mentioned range. Is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, still more preferably 25 to 55% by mass, and still more preferably 30 to 50% by mass with respect to the total amount (100% by mass).
〔環形成原子数６～２０の脂環基又は複素環基を有する重合性化合物（ａ２）〕
　エネルギー線重合性化合物を含む緩衝層形成用組成物で用いる成分（ａ２）は、環形成原子数６～２０の脂環基又は複素環基を有する重合性化合物であり、少なくとも１つの（メタ）アクリロイル基を有する化合物であることが好ましい。この成分（ａ２）を用いることで、得られる緩衝層形成用組成物の成膜性を向上させることができる。 [Polymerizable compound (a2) having an alicyclic group or heterocyclic group having 6 to 20 ring atoms]
The component (a2) used in the composition for forming a buffer layer containing an energy beam polymerizable compound is a polymerizable compound having an alicyclic group or heterocyclic group having 6 to 20 ring-forming atoms, and at least one (meth) A compound having an acryloyl group is preferred. By using this component (a2), the film formability of the obtained composition for forming a buffer layer can be improved.
　成分（ａ２）が有する脂環基又は複素環基の環形成原子数は、好ましくは６～２０であるが、より好ましくは６～１８、更に好ましくは６～１６、より更に好ましくは７～１２である。
　当該複素環基の環構造を形成する原子としては、例えば、炭素原子、窒素原子、酸素原子、硫黄原子等が挙げられる。
　なお、本発明において、環形成原子数とは、原子が環状に結合した構造の化合物の当該環自体を構成する原子の数を表し、環を構成しない原子（例えば、環を構成する原子に結合した水素原子）や、当該環が置換基によって置換される場合の置換基に含まれる原子は環形成原子数には含まない。 The number of ring-forming atoms of the alicyclic group or heterocyclic group contained in the component (a2) is preferably 6 to 20, more preferably 6 to 18, still more preferably 6 to 16, and still more preferably 7 to 12. It is.
Examples of the atoms forming the ring structure of the heterocyclic group include a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom.
In the present invention, the number of ring-forming atoms means the number of atoms constituting the ring itself of a compound having a structure in which atoms are bonded in a ring, and is not bonded to an atom (for example, bonded to an atom constituting the ring). Hydrogen atoms) and atoms included in a substituent when the ring is substituted by a substituent are not included in the number of ring-forming atoms.
　具体的な成分（ａ２）としては、例えば、イソボルニル（メタ）アクリレート、ジシクロペンテニル（メタ）アクリレート、ジシクロペンタニル（メタ）アクリレート、ジシクロペンテニルオキシ（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、アダマンタン（メタ）アクリレート等の脂環基含有（メタ）アクリレート；テトラヒドロフルフリル（メタ）アクリレート、モルホリン（メタ）アクリレート等の複素環基含有（メタ）アクリレート；等が挙げられる。
　なお、成分（ａ２）は、単独で又は２種以上を組み合わせて用いてもよい。
　これらの中でも、脂環基含有（メタ）アクリレートが好ましく、イソボルニル（メタ）アクリレートがより好ましい。 Specific components (a2) include, for example, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, And alicyclic group-containing (meth) acrylates such as adamantane (meth) acrylate; heterocyclic group-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate and morpholine (meth) acrylate;
In addition, you may use a component (a2) individually or in combination of 2 or more types.
Among these, alicyclic group-containing (meth) acrylate is preferable, and isobornyl (meth) acrylate is more preferable.
　エネルギー線重合性化合物を含む緩衝層形成用組成物中の成分（ａ２）の含有量は、押し込み深さ（Ｚ）が上述の範囲となる緩衝層を形成する観点、及び得られる緩衝層形成用組成物の成膜性を向上させる観点から、緩衝層形成用組成物の全量（１００質量％）に対して、好ましくは１０～７０質量％、より好ましくは２０～６０質量％、更に好ましくは２５～５５質量％、より更に好ましくは３０～５０質量％である。 The content of the component (a2) in the buffer layer forming composition containing the energy beam polymerizable compound is such that the indentation depth (Z) forms a buffer layer having the above-mentioned range, and the obtained buffer layer forming From the viewpoint of improving the film formability of the composition, it is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 25% with respect to the total amount (100% by mass) of the buffer layer forming composition. It is ˜55 mass%, more preferably 30-50 mass%.
〔官能基を有する重合性化合物（ａ３）〕
　エネルギー線重合性化合物を含む緩衝層形成用組成物で用いる成分（ａ３）は、水酸基、エポキシ基、アミド基、アミノ基等の官能基を含有する重合性化合物であり、少なくとも１つの（メタ）アクリロイル基を有する化合物であることが好ましい。
　成分（ａ３）は、成分（ａ１）との相溶性が良好であり、緩衝層形成用組成物の粘度を適度な範囲に調整し、当該組成物から形成される緩衝層の弾性率も適度な範囲とすることができる。そのため、この成分（ａ３）を用いることで、押し込み深さ（Ｚ）が上述の範囲となる緩衝層を形成することができる。
　成分（ａ３）としては、例えば、水酸基含有（メタ）アクリレート、エポキシ基含有（メタ）アクリレート、アミド基含有化合物、アミノ基含有（メタ）アクリレート等が挙げられる。 [Polymerizable compound having functional group (a3)]
The component (a3) used in the buffer layer-forming composition containing the energy beam polymerizable compound is a polymerizable compound containing a functional group such as a hydroxyl group, an epoxy group, an amide group, or an amino group, and at least one (meth) A compound having an acryloyl group is preferred.
Component (a3) has good compatibility with component (a1), the viscosity of the composition for forming a buffer layer is adjusted to an appropriate range, and the elastic modulus of the buffer layer formed from the composition is also appropriate. It can be a range. Therefore, by using this component (a3), it is possible to form a buffer layer having an indentation depth (Z) in the above range.
Examples of the component (a3) include a hydroxyl group-containing (meth) acrylate, an epoxy group-containing (meth) acrylate, an amide group-containing compound, and an amino group-containing (meth) acrylate.
　水酸基含有（メタ）アクリレートとしては、例えば、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、３－ヒドロキシプロピル（メタ）アクリレート、２－ヒドロキシブチル（メタ）アクリレート、３－ヒドロキシブチル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレート、フェニルヒドロキシプロピル（メタ）アクリレート等が挙げられる。
　エポキシ基含有（メタ）アクリレートとしては、例えば、グリシジル（メタ）アクリレート、メチルグリシジル（メタ）アクリレート、アリルグリシジルエーテル等が挙げられる。
　アミド基含有化合物としては、例えば、（メタ）アクリルアミド、Ｎ，Ｎ－ジメチル（メタ）アクリルアミド、Ｎ－ブチル（メタ）アクリルアミド、Ｎ－メチロール（メタ）アクリルアミド、Ｎ－メチロールプロパン（メタ）アクリルアミド、Ｎ－メトキシメチル（メタ）アクリルアミド、Ｎ－ブトキシメチル（メタ）アクリルアミド等が挙げられる。
　アミノ基含有（メタ）アクリレートとしては、例えば、第１級アミノ基含有（メタ）アクリレート、第２級アミノ基含有（メタ）アクリレート、第３級アミノ基含有（メタ）アクリレート等が挙げられる。
　また、その他の官能基を有する重合性化合物としては、ヒドロキシエチルビニルエーテル、ヒドロキシブチルビニルエーテル、Ｎ－ビニルホルムアミド、Ｎ－ビニルピロリドン、Ｎ－ビニルカプロラクタム等のビニル化合物等が挙げられる。
　なお、成分（ａ３）は、単独で又は２種以上を組み合わせて用いてもよい。 Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxy Examples include butyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and phenylhydroxypropyl (meth) acrylate.
Examples of the epoxy group-containing (meth) acrylate include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.
Examples of amide group-containing compounds include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N -Methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide and the like.
Examples of amino group-containing (meth) acrylates include primary amino group-containing (meth) acrylates, secondary amino group-containing (meth) acrylates, and tertiary amino group-containing (meth) acrylates.
Examples of other polymerizable compounds having a functional group include vinyl compounds such as hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam.
In addition, you may use a component (a3) individually or in combination of 2 or more types.
　これらの中でも、押し込み深さ（Ｚ）が上述の範囲となる緩衝層を形成する観点から、水酸基含有（メタ）アクリレートが好ましく、フェニルヒドロキシプロピル（メタ）アクリレート等の芳香環を有する水酸基含有（メタ）アクリレートがより好ましい。 Among these, from the viewpoint of forming a buffer layer having an indentation depth (Z) in the above range, a hydroxyl group-containing (meth) acrylate is preferable, and a hydroxyl group-containing (meta) having an aromatic ring such as phenylhydroxypropyl (meth) acrylate is preferred. ) Acrylate is more preferred.
　エネルギー線重合性化合物を含む緩衝層形成用組成物中の成分（ａ３）の含有量は、押し込み深さ（Ｚ）が上述の範囲となる緩衝層を形成する観点、及び得られる緩衝層形成用組成物の成膜性を向上させる観点から、緩衝層形成用組成物の全量（１００質量％）に対して、好ましくは５～４０質量％、より好ましくは７～３５質量％、更に好ましくは１０～３０質量％、より更に好ましくは１３～２５質量％である。 The content of the component (a3) in the buffer layer forming composition containing the energy beam polymerizable compound is such that the indentation depth (Z) forms a buffer layer in the above range, and the obtained buffer layer forming From the viewpoint of improving the film formability of the composition, it is preferably 5 to 40% by mass, more preferably 7 to 35% by mass, and still more preferably 10% with respect to the total amount (100% by mass) of the buffer layer forming composition. To 30% by mass, and more preferably 13 to 25% by mass.
　また、緩衝層形成用組成物中の成分に含有される（ａ２）と成分（ａ３）との含有量比［（ａ２）／（ａ３）］（質量比）は、好ましくは０．５～３．０、より好ましくは１．０～３．０、更に好ましくは１．３～３．０、より更に好ましくは１．５～２．８である。
　当該含有量比が０．５以上であれば、得られる緩衝層形成用組成物の成膜性を良好とすることができる。一方、当該含有量比が３．０以下であれば、押し込み深さ（Ｚ）が上述の範囲となる緩衝層を形成することができる。 The content ratio [(a2) / (a3)] (mass ratio) of (a2) and component (a3) contained in the components in the buffer layer forming composition is preferably 0.5 to 3 0.0, more preferably 1.0 to 3.0, still more preferably 1.3 to 3.0, and still more preferably 1.5 to 2.8.
If the said content ratio is 0.5 or more, the film-forming property of the composition for buffer layer formation obtained can be made favorable. On the other hand, if the content ratio is 3.0 or less, a buffer layer having an indentation depth (Z) in the above range can be formed.
〔成分（ａ１）～（ａ３）以外の重合性化合物〕
　エネルギー線重合性化合物を含む緩衝層形成用組成物には、本発明の効果を損なわない範囲において、上記の成分（ａ１）～（ａ３）以外のその他の重合性化合物を含有してもよい。
　その他の重合性化合物としては、例えば、炭素数１～２０のアルキル基を有するアルキル（メタ）アクリレート；スチレン等のビニル化合物：等が挙げられる。
　なお、これらのその他の重合性化合物は、単独で又は２種以上を組み合わせて用いてもよい。 [Polymerizable compounds other than components (a1) to (a3)]
The composition for forming a buffer layer containing the energy beam polymerizable compound may contain other polymerizable compounds other than the components (a1) to (a3) as long as the effects of the present invention are not impaired.
Examples of other polymerizable compounds include alkyl (meth) acrylates having an alkyl group having 1 to 20 carbon atoms; vinyl compounds such as styrene: and the like.
In addition, you may use these other polymeric compounds individually or in combination of 2 or more types.
　エネルギー線重合性化合物を含む緩衝層形成用組成物中のその他の重合性化合物の含有量は、好ましくは０～２０質量％、より好ましくは０～１０質量％、更に好ましくは０～５質量％、より更に好ましくは０～２質量％である。 The content of the other polymerizable compound in the composition for forming a buffer layer containing the energy beam polymerizable compound is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, and still more preferably 0 to 5% by mass. More preferably, it is 0 to 2% by mass.
〔光重合開始剤〕
　エネルギー線重合性化合物を含む緩衝層形成用組成物には、緩衝層を形成する際、光照射による重合時間の短縮及び光照射量の低減の観点から、さらに光重合開始剤を含有することが好ましい。
　光重合開始剤としては、例えば、ベンゾイン化合物、アセトフェノン化合物、アシルフォスフィノキサイド化合物、チタノセン化合物、チオキサントン化合物、パーオキサイド化合物等の光重合開始剤、アミンやキノン等の光増感剤等が挙げられ、より具体的には、例えば、１－ヒドロキシシクロヘキシルフェニルケトン、２－ヒドロキシ－２－メチル－１－フェニル－プロパン－１－オン、ベンゾイン、ベンゾインメチルエーテル、ベンゾインエチルエーテル、ベンゾインイソプロピルエーテル等が挙げられる。
　これらの光重合開始剤は、単独で又は２種以上を組み合わせて用いることができる。 (Photopolymerization initiator)
When forming the buffer layer, the composition for forming the buffer layer containing the energy ray polymerizable compound may further contain a photopolymerization initiator from the viewpoint of shortening the polymerization time by light irradiation and reducing the light irradiation amount. preferable.
Examples of the photopolymerization initiator include photopolymerization initiators such as benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds, and photosensitizers such as amines and quinones. More specifically, for example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, etc. Can be mentioned.
These photopolymerization initiators can be used alone or in combination of two or more.
　エネルギー線重合性化合物を含む緩衝層形成用組成物中の光重合開始剤の含有量は、エネルギー線重合性化合物の合計量１００質量部に対して、好ましくは０．０５～１５質量部、より好ましくは０．１～１０質量部、更に好ましくは０．３～５質量部である。 The content of the photopolymerization initiator in the composition for forming a buffer layer containing the energy beam polymerizable compound is preferably 0.05 to 15 parts by mass with respect to 100 parts by mass of the total amount of the energy beam polymerizable compound. The amount is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass.
〔その他の添加剤及び樹脂成分〕
　また、上記エネルギー線重合性化合物を含む緩衝層形成用組成物には、本発明の効果を損なわない範囲において、その他の添加剤や樹脂成分を含有してもよい。
　その他の添加剤としては、例えば、酸化防止剤、軟化剤（可塑剤）、充填剤、防錆剤、顔料、帯電防止剤、難燃剤、染料等が挙げられる。
　これらの添加剤を配合する場合、緩衝層形成用組成物中の各添加剤の含有量は、エネルギー線重合性化合物の合計量１００質量部に対して、好ましくは０．０１～６質量部、より好ましくは０．１～３質量部である。 [Other additives and resin components]
Moreover, the composition for buffer layer formation containing the said energy ray polymeric compound may contain another additive and a resin component in the range which does not impair the effect of this invention.
Examples of other additives include antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, antistatic agents, flame retardants, and dyes.
When these additives are blended, the content of each additive in the composition for forming a buffer layer is preferably 0.01 to 6 parts by mass with respect to 100 parts by mass of the total amount of the energy beam polymerizable compound, More preferably, it is 0.1 to 3 parts by mass.
（緩衝層形成用樹脂フィルム）
　また、上記緩衝層形成用樹脂フィルム（以下、「緩衝層用樹脂フィルム」ともいう）としては、押し込み深さ（Ｚ）を上述の範囲となる緩衝層を形成できる樹脂フィルムであれば特に制限はない。例えば、加工後の表面保護フィルムを粘着テープやヒートシール材等を使用して剥離するような場合に、これらの粘着テープやヒートシール材との接着力を向上させる観点から、ポリエチレンフィルムを用いることが好ましい。ポリエチレンフィルムの原料となるポリエチレン樹脂としては、例えば、高密度ポリエチレン（ＨＤＰＥ）、低密度ポリエチレン（ＬＤＰＥ）、直鎖状低密度ポリエチレン（ＬＬＤＰＥ）等を用いることができる。 (Resin film for buffer layer formation)
The buffer layer forming resin film (hereinafter also referred to as “buffer layer resin film”) is not particularly limited as long as it is a resin film capable of forming a buffer layer having an indentation depth (Z) in the above range. Absent. For example, when the surface protective film after processing is peeled off using an adhesive tape or a heat seal material, a polyethylene film is used from the viewpoint of improving the adhesive force with the adhesive tape or the heat seal material. Is preferred. Examples of the polyethylene resin that is a raw material for the polyethylene film include high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE).
　緩衝層の厚さは、上記支持体の剛軟度が上記範囲であれば特に制限はされないが、本発明の表面保護フィルムを光学部材又は電子部材に貼り付け及び剥離する際の作業性を良好とする観点から、好ましくは５～１００μｍ、より好ましくは１０～８０μｍ、更に好ましくは１５～５０μｍである。 The thickness of the buffer layer is not particularly limited as long as the bending resistance of the support is within the above range, but the workability when attaching and peeling the surface protective film of the present invention to an optical member or an electronic member is good. In view of the above, it is preferably 5 to 100 μm, more preferably 10 to 80 μm, and still more preferably 15 to 50 μm.
（基材）
　上記支持体は、さらに、基材を有することが好ましい。基材が設けられる場合、上記緩衝層は、該基材の一方の面に設けられる。
　基材としては、上記支持体の剛軟度が上記範囲であれば特に制限はされないが、耐水性及び耐熱性の観点から、樹脂フィルム（以下、「基材用樹脂フィルム」ともいう）が好ましい。
　当該基材用樹脂フィルムを構成する樹脂としては、例えば、ポリエチレンテレフタレート、ポリエチレンナフタレート、ポリブチレンテレフタレート、全芳香族ポリエステル等のポリエステル、ポリアミド、ポリイミド、ポリアセタール、ポリカーボネート、変性ポリフェニレンオキシド、ポリフェニレンスルフィド、ポリスルホン、ポリエーテルケトン、二軸延伸ポリプロピレン等が挙げられる。
　これらの樹脂の中でも、ポリエステル、ポリアミド、ポリイミド、二軸延伸ポリプロピレンから選ばれる１種以上が好ましく、ポリエステルがより好ましく、ポリエチレンテレフタレートが更に好ましい。
　また、上記基材は、上記の樹脂から選ばれる１種以上又は２種以上の樹脂からなる単層フィルムであってもよく、これらの樹脂フィルムを２種以上積層したフィルムであってもよい。 (Base material)
The support preferably further has a substrate. When a base material is provided, the buffer layer is provided on one surface of the base material.
The substrate is not particularly limited as long as the bending resistance of the support is in the above range, but a resin film (hereinafter also referred to as “resin film for substrate”) is preferable from the viewpoint of water resistance and heat resistance. .
Examples of the resin constituting the resin film for a substrate include polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, wholly aromatic polyester, polyamide, polyimide, polyacetal, polycarbonate, modified polyphenylene oxide, polyphenylene sulfide, and polysulfone. , Polyether ketone, biaxially oriented polypropylene and the like.
Among these resins, one or more selected from polyester, polyamide, polyimide, and biaxially stretched polypropylene are preferable, polyester is more preferable, and polyethylene terephthalate is still more preferable.
Further, the substrate may be a single layer film made of one or more or two or more resins selected from the above resins, or may be a film in which two or more of these resin films are laminated.
　また、本発明で用いる基材には、本発明の効果を損なわない範囲において、フィラー、着色剤、帯電防止剤、酸化防止剤、有機滑剤、触媒等を含有させてもよい。
　また、基材は、透明なものであっても、不透明なものであってもよく、所望により着色されていてもよい。なお、例えば、上記緩衝層又は後述する粘着剤層がエネルギー線重合性化合物を含む場合などは、エネルギー線重合性化合物を硬化させるために使用するエネルギー線の波長に対して透過性を有する必要がある。すなわち、エネルギー線として紫外線を用いる場合においては、基材は光透過性フィルムが使用される。また、エネルギー線として電子線を用いる場合においては、基材は光透過性である必要はなく、着色が施されたフィルムを用いても良い。
　なお、本発明で用いる基材の少なくとも一方の表面には、緩衝層及び／又は粘着剤層との密着性を向上させるために、コロナ処理等の接着処理を施してもよく、後述の易接着層を設けてもよい。
　また、基材の厚さは、上記支持体の剛軟度が上記範囲であれば特に制限はされないが、表面保護フィルムに要求される性能等に応じて調整され、好ましくは１０～３００μｍであり、特に好ましくは３０～１５０μｍである。 Further, the base material used in the present invention may contain a filler, a colorant, an antistatic agent, an antioxidant, an organic lubricant, a catalyst, and the like as long as the effects of the present invention are not impaired.
Further, the substrate may be transparent or opaque, and may be colored as desired. For example, when the buffer layer or the pressure-sensitive adhesive layer described later contains an energy beam polymerizable compound, the buffer layer or the pressure-sensitive adhesive layer needs to have transparency to the wavelength of the energy beam used for curing the energy beam polymerizable compound. is there. That is, when ultraviolet rays are used as the energy rays, a light transmissive film is used as the substrate. Moreover, when using an electron beam as an energy beam, the base material does not need to be light-transmitting, and a colored film may be used.
In addition, in order to improve the adhesion with the buffer layer and / or the pressure-sensitive adhesive layer, at least one surface of the base material used in the present invention may be subjected to an adhesion treatment such as a corona treatment, which will be described later. A layer may be provided.
The thickness of the substrate is not particularly limited as long as the bending resistance of the support is in the above range, but is adjusted according to the performance required for the surface protective film, and is preferably 10 to 300 μm. Particularly preferred is 30 to 150 μm.
（樹脂層）
　上記支持体は、さらに、上記基材の緩衝層が設けられる面と反対側の面に樹脂層を有していてもよい。
　樹脂層としては、上記支持体の剛軟度が上記範囲であれば特に制限はされないが、例えば、上述した緩衝層用樹脂フィルムと同じ樹脂フィルムを用いることができる。後述する粘着剤層との密着性を向上させることができる観点から、ポリエチレンフィルムであることが好ましい。ポリエチレンフィルムの原料となる樹脂は、例えば、高密度ポリエチレン（ＨＤＰＥ）、低密度ポリエチレン（ＬＤＰＥ）、直鎖状低密度ポリエチレン（ＬＬＤＰＥ）等を用いることができる。
　樹脂層の厚さは、上記支持体の剛軟度が上記範囲であれば特に制限はされないが、本発明の表面保護フィルムを光学部材又は電子部材に貼り付け及び剥離する際の作業性を良好とする観点から、好ましくは５～１００μｍ、より好ましくは１０～８０μｍ、更に好ましくは１５～５０μｍである。 (Resin layer)
The support may further have a resin layer on the surface opposite to the surface on which the buffer layer of the substrate is provided.
The resin layer is not particularly limited as long as the bending resistance of the support is in the above range. For example, the same resin film as the buffer layer resin film described above can be used. From the viewpoint of improving the adhesion with the pressure-sensitive adhesive layer described later, a polyethylene film is preferable. For example, high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or the like can be used as the resin that is a raw material for the polyethylene film.
The thickness of the resin layer is not particularly limited as long as the bending resistance of the support is within the above range, but the workability when the surface protective film of the present invention is attached to and peeled from an optical member or an electronic member is good. In view of the above, it is preferably 5 to 100 μm, more preferably 10 to 80 μm, and still more preferably 15 to 50 μm.
＜粘着剤層＞
　本発明の表面保護フィルムが有する粘着剤層を形成する粘着剤としては、特に限定されないが、例えば、アクリル系粘着剤、ウレタン系粘着剤、シリコーン系粘着剤、ゴム系粘着剤、ポリエステル系粘着剤が挙げられる。
　これらの粘着剤は、単独で又は２種以上を組み合わせて用いてもよい。 <Adhesive layer>
Although it does not specifically limit as an adhesive which forms the adhesive layer which the surface protection film of this invention has, For example, an acrylic adhesive, a urethane adhesive, a silicone adhesive, a rubber adhesive, a polyester adhesive Is mentioned.
These pressure-sensitive adhesives may be used alone or in combination of two or more.
　上記粘着剤では、アクリル系粘着剤であることが好ましい。また、当該アクリル系粘着剤である場合、一般的に、アクリル系共重合体（Ａ）を含むアクリル系粘着剤（以下、アクリル系粘着剤組成物ともいう）である。
　アクリル系共重合体（Ａ）は、通常、粘着剤層において粘着成分を構成するものであり、以下、メインポリマーともいう。
　なお、以下の説明では、アクリル系粘着剤である場合の例を主に説明するが、他の種類の粘着剤の場合も同様であり、その際には、粘着成分を構成するメインポリマーがアクリル系重合体（Ａ）以外のポリマーが使用される。
　アクリル系共重合体（Ａ）は、アルキル（メタ）アクリレートを主モノマーとして含むモノマー成分（以下、「共重合体成分」ともいう）を共重合したものである。アルキル（メタ）アクリレートとしては、アルキル基の炭素数が１～１８のものが挙げられ、メチル（メタ）アクリレート、エチル（メタ）アクリレート、イソプロピル（メタ）アクリレート、ｎ－プロピル（メタ）アクリレート、ブチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、ｎ－オクチル（メタ）アクリレート、イソオクチル（メタ）アクリレート、ノニル（メタ）アクリレート、デシル（メタ）アクリレート、ウンデシル（メタ）アクリレート、ドデシル（メタ）アクリレート等が挙げられる。
　アクリル系共重合体（Ａ）は、共重合体成分としてアルキル（メタ）アクリレートを、共重合体成分全量に対して、好ましくは５０質量％以上、より好ましくは５０～９９．５質量％含有する。 In the said adhesive, it is preferable that it is an acrylic adhesive. Moreover, when it is the said acrylic adhesive, it is generally an acrylic adhesive (henceforth an acrylic adhesive composition) containing an acrylic copolymer (A).
The acrylic copolymer (A) usually constitutes a pressure-sensitive adhesive component in the pressure-sensitive adhesive layer, and is hereinafter also referred to as a main polymer.
In the following description, an example in the case of an acrylic pressure-sensitive adhesive will be mainly described, but the same applies to other types of pressure-sensitive adhesives. In this case, the main polymer constituting the pressure-sensitive adhesive component is acrylic. A polymer other than the polymer (A) is used.
The acrylic copolymer (A) is obtained by copolymerizing a monomer component (hereinafter also referred to as “copolymer component”) containing an alkyl (meth) acrylate as a main monomer. Examples of the alkyl (meth) acrylate include those having 1 to 18 carbon atoms in the alkyl group, such as methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, and butyl. (Meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate Etc.
The acrylic copolymer (A) contains an alkyl (meth) acrylate as a copolymer component, preferably 50% by mass or more, more preferably 50 to 99.5% by mass, based on the total amount of the copolymer component. .
　アクリル系共重合体（Ａ）は、共重合体成分として、アルキル（メタ）アクリレートのうち、アルキル基の炭素数が１又は２であるアルキル（メタ）アクリレートを、共重合体成分全量に対して５～５０質量％含有するものであることが好ましい。含有量が５質量％以上では、粘着力、特に、アクリル系粘着剤がエネルギー線硬化型粘着剤である場合は、エネルギー線照射後の粘着力が高くなりすぎて、剥離性能が悪くなることを抑制できる。また、初期粘着力が高くなりすぎず、十分なリワーク性を得られる。含有量が５０質量％以下であれば、粘着力が不足し、表面保護フィルムが、後述する各工程中に電子部材及び光学部材から不意に剥がれたりして、電子部材及び光学部材を十分に保護できなくなることを防止できる。
　以上の観点から、上記アクリル系共重合体（Ａ）は、共重合体成分として、アルキル基の炭素数が１又は２であるアルキル（メタ）アクリレートを、共重合体成分全量に対して１０～４０質量％含むことがより好ましく、１５～３５質量％含むことがさらに好ましい。
　なお、アルキル基の炭素数が１又は２であるアルキル（メタ）アクリレートとしては、メチル（メタ）アクリレート、エチル（メタ）アクリレートが挙げられるが、これらの中では、メチルアクリレート、メチルメタクリレートが好ましい。 The acrylic copolymer (A) contains, as a copolymer component, an alkyl (meth) acrylate having an alkyl group having 1 or 2 carbon atoms out of the alkyl (meth) acrylate, based on the total amount of the copolymer component. The content is preferably 5 to 50% by mass. When the content is 5% by mass or more, the adhesive strength, particularly when the acrylic adhesive is an energy ray curable adhesive, the adhesive strength after irradiation with energy rays becomes too high, and the peeling performance is deteriorated. Can be suppressed. Further, the initial adhesive strength does not become too high, and sufficient reworkability can be obtained. If the content is 50% by mass or less, the adhesive strength is insufficient, and the surface protection film may be unexpectedly peeled off from the electronic member and the optical member during each step to be described later, thereby sufficiently protecting the electronic member and the optical member. It can be prevented from becoming impossible.
From the above viewpoints, the acrylic copolymer (A) contains, as a copolymer component, an alkyl (meth) acrylate having an alkyl group having 1 or 2 carbon atoms in an amount of 10 to More preferably, it is contained in an amount of 40% by mass, more preferably 15-35% by mass.
Examples of the alkyl (meth) acrylate having 1 or 2 carbon atoms in the alkyl group include methyl (meth) acrylate and ethyl (meth) acrylate. Among these, methyl acrylate and methyl methacrylate are preferable.
　また、アクリル系共重合体（Ａ）は、共重合体成分として、アルキル（メタ）アクリレートのうち、アルキル基の炭素数が３以上であるアルキル（メタ）アクリレートを、共重合体成分全量に対して３０～８５質量％含有することが好ましい。アルキル基の炭素数が３以上であるアルキル（メタ）アクリレートの含有量をこのような範囲とすることで、適切な粘着性能と剥離性能を表面保護フィルムに付与しやすくなる。このような観点から、アルキル基の炭素数が３以上であるアルキル（メタ）アクリレートの含有量は、４０～８０質量％であることがより好ましく、４５～７５質量％であることがさらに好ましい。 In addition, the acrylic copolymer (A) contains, as a copolymer component, an alkyl (meth) acrylate having an alkyl group with 3 or more carbon atoms in the alkyl (meth) acrylate, based on the total amount of the copolymer component. The content is preferably 30 to 85% by mass. By making content of the alkyl (meth) acrylate whose carbon number of an alkyl group is 3 or more into such a range, it becomes easy to provide suitable adhesive performance and peeling performance to a surface protection film. From such a viewpoint, the content of the alkyl (meth) acrylate having 3 or more carbon atoms in the alkyl group is more preferably 40 to 80% by mass, and further preferably 45 to 75% by mass.
　上記アルキル基の炭素数が３以上のアルキル（メタ）アクリレートは、アルキル基の炭素数が３～８であるアルキル（メタ）アクリレートであることが好ましく、アルキル基の炭素数が４～８であるアルキル（メタ）アクリレートであることがより好ましく、アルキル基の炭素数が４～８であるアルキルアクリレートがさらに好ましい。具体的には、ｎ－ブチルアクリレート、２－エチルヘキシルアクリレート、ｎ－オクチルアクリレート、イソオクチルアクリレート等が好ましい。 The alkyl (meth) acrylate having 3 or more carbon atoms in the alkyl group is preferably an alkyl (meth) acrylate in which the alkyl group has 3 to 8 carbon atoms, and the alkyl group has 4 to 8 carbon atoms. Alkyl (meth) acrylates are more preferred, and alkyl acrylates having an alkyl group with 4 to 8 carbon atoms are more preferred. Specifically, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, and the like are preferable.
　アクリル系共重合体（Ａ）は、共重合体成分として、アルキル（メタ）アクリレート以外の重合性モノマーを含有することが好ましく、具体的には官能基含有モノマーを含有することが好ましい。官能基含有モノマーは、後述する不飽和基含有化合物をアクリル系共重合体（Ａ）に結合させるためや、後述する架橋剤との反応のために必要な官能基を提供する。官能基含有モノマーは、重合性の二重結合と、ヒドロキシル基、カルボキシル基、アミノ基、置換アミノ基、エポキシ基等の官能基とを分子内に有するモノマーである。 The acrylic copolymer (A) preferably contains a polymerizable monomer other than alkyl (meth) acrylate as the copolymer component, and specifically contains a functional group-containing monomer. The functional group-containing monomer provides a functional group necessary for bonding an unsaturated group-containing compound, which will be described later, to the acrylic copolymer (A) and for reaction with a crosslinking agent, which will be described later. The functional group-containing monomer is a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group in the molecule.
　ここで、上記アクリル系共重合体（Ａ）は、共重合体成分として、カルボキシル基含有モノマーを含まず、又はカルボキシル基含有モノマーを含有していても、その含有量は、共重合体成分全量に対して５質量％未満となるものであることが好ましい。カルボキシル基含有モノマーを含有せず、または、含有量を少なくすることで、粘着剤層は、エネルギー線照射後の粘着力の過度な上昇を抑制し、表面保護フィルムの剥離性を良好にできる。また、初期粘着力の過度な上昇も抑制し、リワーク性も良好にできる。
　これらの観点から、共重合体成分におけるカルボキシル基含有モノマーの含有量は、３質量％未満がより好ましく、１質量％未満がさらに好ましく、さらには、カルボキシル基含有モノマーを共重合体成分として含有しないことが最も好ましい。なお、カルボキシル基含有モノマーとしては、アクリル酸、メタクリル酸、イタコン酸等が挙げられる。 Here, the acrylic copolymer (A) does not contain a carboxyl group-containing monomer as a copolymer component, or even if it contains a carboxyl group-containing monomer, the content thereof is the total amount of the copolymer component. It is preferable that the amount is less than 5% by mass. By not containing a carboxyl group-containing monomer or reducing the content, the pressure-sensitive adhesive layer can suppress an excessive increase in the adhesive strength after irradiation with energy rays and can improve the peelability of the surface protective film. In addition, an excessive increase in initial adhesive force can be suppressed, and reworkability can be improved.
From these viewpoints, the content of the carboxyl group-containing monomer in the copolymer component is preferably less than 3% by mass, more preferably less than 1% by mass, and further, no carboxyl group-containing monomer is contained as a copolymer component. Most preferred. Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, itaconic acid and the like.
　上記官能基含有モノマーとしては、好ましくは、ヒドロキシル基含有化合物が用いられ、より好ましくは、ヒドロキシル基含有（メタ）アクリレートが用いられる。そして、アクリル系共重合体（Ａ）は、ヒドロキシル基含有（メタ）アクリレートを共重合体成分全量に対して０．２～４０質量％含む共重合体成分を共重合したものであることが好ましい。ヒドロキシル基含有（メタ）アクリレートの含有量が上記範囲内となることで、アクリル系共重合体（Ａ）は後述する架橋剤で適切に架橋することが可能になる。
　また、ヒドロキシル基含有（メタ）アクリレートの上記含有量は、０．３～３０質量％であることがより好ましく、０．５～３０質量％であることがさらに好ましい。ヒドロキシル基含有（メタ）アクリレートが１～３０質量％であると、適切な粘着性能を確保しつつ、後述する不飽和基含有化合物を適切に側鎖に導入でき、さらには架橋剤でアクリル系共重合体（Ａ）を適切に架橋することが可能になる。
　ヒドロキシル基含有（メタ）アクリレートの具体例としては、２－ヒドロキシメチル（メタ）アクリレート、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、２－ヒドロキシブチル（メタ）アクリレート等が挙げられる。
　以上の官能基含有モノマーは、１種単独で、または２種以上を組み合わせて用いてもよい。 As the functional group-containing monomer, a hydroxyl group-containing compound is preferably used, and more preferably, a hydroxyl group-containing (meth) acrylate is used. The acrylic copolymer (A) is preferably obtained by copolymerizing a copolymer component containing 0.2 to 40% by mass of hydroxyl group-containing (meth) acrylate with respect to the total amount of the copolymer component. . When the content of the hydroxyl group-containing (meth) acrylate is within the above range, the acrylic copolymer (A) can be appropriately crosslinked with a crosslinking agent described later.
The content of the hydroxyl group-containing (meth) acrylate is more preferably 0.3 to 30% by mass, and further preferably 0.5 to 30% by mass. When the hydroxyl group-containing (meth) acrylate is 1 to 30% by mass, an unsaturated group-containing compound to be described later can be appropriately introduced into the side chain while ensuring appropriate adhesive performance. It becomes possible to appropriately crosslink the polymer (A).
Specific examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and the like. Can be mentioned.
The above functional group-containing monomers may be used alone or in combination of two or more.
　アクリル系共重合体（Ａ）は、上記のモノマーの他にも、アルキル（メタ）アクリレートおよび官能基含有モノマー以外の（メタ）アクリル酸エステル、ジアルキル（メタ）アクリルアミド、蟻酸ビニル、酢酸ビニル、スチレン、ビニルアセテート等を共重合体成分として含んでいてもよい。（メタ）アクリル酸アルキルエステルおよび官能基含有モノマー以外の（メタ）アクリル酸エステルとしては、（メタ）アクリル酸アルコキシアルキルエステル、（メタ）アクリル酸アルキレンオキシアルキルエステル、（メタ）アクリル酸ノニルフェノキシポリエチレングリコール、アクリル酸テトラヒドロフランフルフリル、ポリエーテルとアクリル酸とのエステルであるジアクリレート類等を用いてもよい。
　また、ジアルキル（メタ）アクリルアミドとしては、ジメチル（メタ）アクリルアミド、ジエチル（メタ）アクリルアミド等が用いられる。ジアルキル（メタ）アクリルアミドは、例えば、粘着剤組成物が、エネルギー線硬化型粘着剤組成物であって、後述するＸ－Ｙ型である際に使用されることが好ましい。ジアルキル（メタ）アクリルアミドを構成モノマーとすることによって、極性の高いウレタン系アクリレート等のエネルギー線重合性化合物（Ｂ）に対するエネルギー線硬化型アクリル系共重合体の相溶性が向上する。
　アクリル系共重合体の重量平均分子量は、好ましくは１００，０００以上であり、より好ましくは１００，０００～１，５００，０００であり、さらに好ましくは１５０，０００～１，０００，０００である。なお、ここでいうアクリル系重合体の重量平均分子量とは、後述する不飽和基含有化合物が反応されてエネルギー線硬化型アクリル系重合体となる場合には、不飽和基含有化合物が反応される前のアクリル系共重合体を意味する。 In addition to the above monomers, the acrylic copolymer (A) includes (meth) acrylic acid esters, dialkyl (meth) acrylamides, vinyl formate, vinyl acetate, styrene other than alkyl (meth) acrylate and functional group-containing monomers. , Vinyl acetate or the like may be included as a copolymer component. As (meth) acrylic acid esters other than (meth) acrylic acid alkyl esters and functional group-containing monomers, (meth) acrylic acid alkoxyalkyl esters, (meth) acrylic acid alkyleneoxyalkyl esters, (meth) acrylic acid nonylphenoxy polyethylene Glycol, tetrahydrofuran furfuryl acrylate, diacrylates which are esters of polyether and acrylic acid, and the like may also be used.
As the dialkyl (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide and the like are used. Dialkyl (meth) acrylamide is preferably used, for example, when the pressure-sensitive adhesive composition is an energy ray-curable pressure-sensitive adhesive composition and is an XY type described later. By using dialkyl (meth) acrylamide as a constituent monomer, the compatibility of the energy beam curable acrylic copolymer with the energy beam polymerizable compound (B) such as a highly polar urethane acrylate is improved.
The weight average molecular weight of the acrylic copolymer is preferably 100,000 or more, more preferably 100,000 to 1,500,000, and further preferably 150,000 to 1,000,000. The weight average molecular weight of the acrylic polymer here refers to the reaction of the unsaturated group-containing compound when an unsaturated group-containing compound described later is reacted to form an energy ray-curable acrylic polymer. It means the previous acrylic copolymer.
　また、上記粘着剤層に用いられる粘着剤組成物は、非エネルギー線硬化型粘着剤組成物であってもよく、エネルギー線硬化型粘着剤組成物であってもよいが、エネルギー線硬化型粘着剤組成物であることが好ましい。
　エネルギー線硬化型粘着剤組成物は、エネルギー線硬化性を有していれば特に限定されないが、Ｘ型のものが好ましい態様として使用される。Ｘ型のエネルギー線硬化型粘着剤組成物とは、粘着剤の粘着成分を構成するメインポリマー自体がエネルギー線硬化性を有するものである。例えば、アクリル系粘着剤組成物の場合は、上述した共重合体成分を共重合してなるアクリル系共重合体の少なくとも一部を、側鎖に不飽和基を有するエネルギー線硬化型アクリル系共重合体とするものである。
　エネルギー線硬化型アクリル系共重合体は、上記したアクリル系共重合体に、不飽和基含有化合物を反応することにより得られるものである。 The pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer may be a non-energy ray-curable pressure-sensitive adhesive composition or an energy-ray-curable pressure-sensitive adhesive composition, An agent composition is preferred.
The energy ray-curable pressure-sensitive adhesive composition is not particularly limited as long as it has energy ray curability, but an X-type one is used as a preferred embodiment. The X-type energy ray-curable pressure-sensitive adhesive composition is one in which the main polymer itself constituting the pressure-sensitive adhesive component of the pressure-sensitive adhesive has energy beam curability. For example, in the case of an acrylic pressure-sensitive adhesive composition, at least a part of the acrylic copolymer obtained by copolymerizing the above-described copolymer component is replaced with an energy ray curable acrylic copolymer having an unsaturated group in the side chain. It is a polymer.
The energy ray curable acrylic copolymer is obtained by reacting the above-mentioned acrylic copolymer with an unsaturated group-containing compound.
　不飽和基含有化合物は、アクリル系共重合体（Ａ）を構成する官能基含有モノマーの官能基に反応しうる置換基を有する。この置換基は、官能基モノマーが有する官能基の種類により様々である。たとえば、官能基がヒドロキシル基またはカルボキシル基の場合、置換基としてはイソシアネート基、エポキシ基等が好ましく、官能基がカルボキシル基の場合、置換基としてはイソシアネート基、エポキシ基等が好ましく、官能基がアミノ基または置換アミノ基の場合、置換基としてはイソシアネート基等が好ましく、官能基がエポキシ基の場合、置換基としてはカルボキシル基が好ましいが、これらの中ではイソシアネート基が好ましい。このような置換基は、不飽和基含有化合物１分子毎に一つずつ含まれている。 The unsaturated group-containing compound has a substituent capable of reacting with a functional group of the functional group-containing monomer constituting the acrylic copolymer (A). This substituent varies depending on the type of functional group possessed by the functional group monomer. For example, when the functional group is a hydroxyl group or a carboxyl group, the substituent is preferably an isocyanate group or an epoxy group. When the functional group is a carboxyl group, the substituent is preferably an isocyanate group or an epoxy group, and the functional group is In the case of an amino group or a substituted amino group, an isocyanate group or the like is preferable as the substituent. When the functional group is an epoxy group, a carboxyl group is preferable as the substituent, and among these, an isocyanate group is preferable. One such substituent is contained in each molecule of the unsaturated group-containing compound.
　不飽和基含有化合物には、エネルギー線重合性炭素－炭素二重結合が、１分子毎に１～５個、好ましくは１～２個含まれている。エネルギー線重合性炭素－炭素二重結合は、（メタ）アクリロイル基であることが好ましい。このような不飽和基含有化合物の具体例としては、（メタ）アクリロイルオキシエチルイソシアネート、メタ－イソプロペニル－α，α－ジメチルベンジルイソシアネート、（メタ）アクリロイルイソシアネート、アリルイソシアネート、グリシジル（メタ）アクリレート、（メタ）アクリル酸等が挙げられる。また、ジイソシアネート化合物またはポリイソシアネート化合物と、ヒドロキシエチル（メタ）アクリレートとの反応により得られるアクリロイルモノイソシアネート化合物；ジイソシアネート化合物またはポリイソシアネート化合物と、ポリオール化合物と、ヒドロキシエチル（メタ）アクリレートとの反応により得られるアクリロイルモノイソシアネート化合物などが挙げられる。 The unsaturated group-containing compound contains 1 to 5, preferably 1 to 2, energy beam polymerizable carbon-carbon double bonds per molecule. The energy beam polymerizable carbon-carbon double bond is preferably a (meth) acryloyl group. Specific examples of such unsaturated group-containing compounds include (meth) acryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, allyl isocyanate, glycidyl (meth) acrylate, Examples include (meth) acrylic acid. Also, an acryloyl monoisocyanate compound obtained by reaction of a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; obtained by reaction of a diisocyanate compound or polyisocyanate compound, a polyol compound and hydroxyethyl (meth) acrylate. And acryloyl monoisocyanate compounds.
　また不飽和基含有化合物としては、下記式（１）のような重合性基含有ポリアルキレンオキシ化合物も使用することができる。 As the unsaturated group-containing compound, a polymerizable group-containing polyalkyleneoxy compound represented by the following formula (1) can also be used.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　式中、Ｒ１は水素またはメチル基、好ましくはメチル基であり、Ｒ２～Ｒ５はそれぞれ独立に水素または炭素数１～４のアルキル基であり、好ましくは水素であり、またｎは２以上の整数であり、好ましくは２～４である。複数存在するＲ２～Ｒ５は互いに同一であっても異なっていてもよい。すなわち、ｎが２以上であるため、上記（１）式で表される重合性基含有ポリアルキレンオキシ基には、Ｒ２が２以上含まれる。この際、２以上存在するＲ２は、互いに同一であっても異なっていてもよい。Ｒ３～Ｒ５についても同様である。ＮＣＯはイソシアネート基を示す。 In the formula, R 1 is hydrogen or a methyl group, preferably a methyl group, R 2 to R 5 are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms, preferably hydrogen, and n is 2 It is an integer above, preferably 2-4. A plurality of R 2 to R 5 may be the same as or different from each other. That is, since n is 2 or more, the polymerizable group-containing polyalkyleneoxy group represented by the formula (1) contains 2 or more R 2 . In this case, two or more R 2 s may be the same or different. The same applies to R 3 to R 5 . NCO represents an isocyanate group.
　不飽和基含有化合物は、アクリル系共重合体（Ａ）が有する官能基１００当量に対し、通常１０～１００当量程度であるが、官能基の当量より少なくすることで架橋剤による架橋が適切に行えるため、好ましくは１５～９５当量、より好ましくは２０～９０当量程度の割合で用いられる。
　不飽和基含有化合物としては、（メタ）アクリロイル基とイソシアネート基とを有する化合物が好ましく用いられ、具体的には（メタ）アクリロイルオキシエチルイソシアネートが好ましい。 The unsaturated group-containing compound is usually about 10 to 100 equivalents with respect to 100 equivalents of the functional group of the acrylic copolymer (A). Since it can be used, it is preferably used in a proportion of about 15 to 95 equivalents, more preferably about 20 to 90 equivalents.
As the unsaturated group-containing compound, a compound having a (meth) acryloyl group and an isocyanate group is preferably used, and specifically, (meth) acryloyloxyethyl isocyanate is preferable.
　エネルギー線硬化型粘着剤組成物は、別の好ましい態様としてＹ型のエネルギー線硬化型粘着剤組成物が使用される。Ｙ型のエネルギー線硬化型粘着剤組成物は、アクリル系共重合体（Ａ）等の粘着剤の粘着成分を構成するメインポリマーとは別に、エネルギー線重合性化合物（Ｂ）が配合されることでエネルギー線硬化性が付与されたものである。 As the energy beam curable pressure-sensitive adhesive composition, a Y-type energy beam curable pressure-sensitive adhesive composition is used as another preferred embodiment. The Y-type energy ray-curable pressure-sensitive adhesive composition contains an energy ray-polymerizable compound (B) separately from the main polymer constituting the pressure-sensitive adhesive component of the pressure-sensitive adhesive such as the acrylic copolymer (A). The energy beam curability is imparted.
　エネルギー線重合性化合物（Ｂ）としては、エポキシアクリレート系、ウレタンアクリレート系、ポリエステルアクリレート系、ポリエーテルアクリレート系などのエネルギー線重合性のオリゴマーや、エネルギー線重合性モノマーが用いられる。
　エネルギー線重合性モノマーとしては、分子内に光重合性炭素－炭素二重結合を少なくとも２個以上有する２官能基以上の低分子量化合物が用いられ、具体的には、トリメチロールプロパントリ（メタ）アクリレート、テトラメチロールメタンテトラ（メタ）アクリレート、ペンタエリスリトールトリ（メタ）アクリレート、ペンタエリスリトールテトラ（メタ）アクリレート、ジペンタエリスリトールモノヒドロキシペンタ（メタ）アクリレート、ジペンタエリスリトールヘキサ（メタ）アクリレートあるいは１，４－ブチレングリコールジ（メタ）アクリレート、１，６－ヘキサンジオールジ（メタ）アクリレートなどが用いられる。 As the energy ray polymerizable compound (B), energy ray polymerizable oligomers such as epoxy acrylate, urethane acrylate, polyester acrylate, and polyether acrylate, and energy ray polymerizable monomers are used.
As the energy ray polymerizable monomer, a low molecular weight compound having two or more functional groups having at least two photopolymerizable carbon-carbon double bonds in the molecule is used. Specifically, trimethylolpropane tri (meth) is used. Acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate or 1,4 -Butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate and the like are used.
　これらの中でも特に、ウレタンアクリレート系オリゴマーが好ましく用いられる。ウレタンアクリレート系オリゴマーは、イソシアナートユニットとポリオールユニットとを含み、末端に（メタ）アクリロイル基を有する化合物である。ウレタンアクリレート系オリゴマーとしては、ポリエーテル型ポリオール、ポリエステル型ポリオール等の末端にヒドロキシル基を有するポリオールと、ポリイソシアナートとの反応により末端イソシアナートウレタンオリゴマーを生成し、その末端の官能基に（メタ）アクリロイル基を有する化合物を反応させて得られる化合物などが挙げられる。このようなウレタンアクリレート系オリゴマーは、（メタ）アクリロイル基の作用により、エネルギー線硬化性を有する。 Among these, urethane acrylate oligomers are preferably used. The urethane acrylate oligomer is a compound including an isocyanate unit and a polyol unit and having a (meth) acryloyl group at the terminal. As urethane acrylate oligomers, terminal isocyanate urethane oligomers are produced by reaction of polyols having hydroxyl groups at the ends, such as polyether-type polyols and polyester-type polyols, with polyisocyanates. ) And the like obtained by reacting a compound having an acryloyl group. Such urethane acrylate oligomers have energy ray curability due to the action of the (meth) acryloyl group.
　ウレタンアクリレート系オリゴマーにおいて使用されるポリイソシアナートとしては、たとえば２，４－トリレンジイソシアナート、２，６－トリレンジイソシアナート、１，３－キシリレンジイソシアナート、１，４－キシリレンジイソシアナート、ジフェニルメタン４，４－ジイソシアナート、イソホロンジイソシアナート、１，３－ビス－(イソシアナトメチル)－シクロヘキサン、４，４’－ジシクロヘキシルメタンジイソシアナートなどが挙げられる。（メタ）アクリロイル基を有する化合物としては、例えば２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、ポリエチレングリコール（メタ）アクリレート等のヒドロキシル基を有する（メタ）アクリレートが挙げられる。また、ヒドロキシル基を有する（メタ）アクリレートとしては、ペンタエリスリトール等の多価アルコールと、（メタ）アクリル酸の部分エステルも挙げられる。 Examples of the polyisocyanate used in the urethane acrylate oligomer include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylylene diisocyanate. Diphenylmethane 4,4-diisocyanate, isophorone diisocyanate, 1,3-bis- (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, and the like. Examples of the compound having a (meth) acryloyl group include (meth) acrylates having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and polyethylene glycol (meth) acrylate. Examples of the (meth) acrylate having a hydroxyl group include polyhydric alcohols such as pentaerythritol and partial esters of (meth) acrylic acid.
　ウレタンアクリレート系オリゴマーは、１分子中に（メタ）アクリロイル基を２つ以上有する２官能基以上のものが好ましいが、Ｘ型と併用しない場合には、３官能基以上のものが好ましく、４官能基以上のものがより好ましい。３官能基以上のものを使用することで、エネルギー線照射後の粘着力を低くしやすく、表面保護フィルムの剥離性能が良好になりやすい。また、ウレタンアクリレート系オリゴマーは、通常１２官能基以下のものが使用される。
　また、ウレタンアクリレート系オリゴマーは、重量平均分子量が１０００～１５０００のものが好ましく、１５００～８５００がより好ましい。
　エネルギー線重合性化合物（Ｂ）は、アクリル系共重合体（Ａ）（メインポリマー）１００質量部に対して、通常５～２００質量部配合されるが、Ｘ型と併用しない場合には、４０～２００質量部が好ましく、７０～１５０質量部がより好ましい。エネルギー線重合性化合物（Ｂ）の含有量を上記の範囲とすることで、エネルギー線照射前の粘着剤層の粘着力を適切に保ちつつ、エネルギー線による硬化で適切に粘着力を低下させることができる。 The urethane acrylate oligomer is preferably a bifunctional or higher functional group having two or more (meth) acryloyl groups in one molecule, but if not used in combination with the X type, a trifunctional or higher functional group is preferred. More than the group is more preferable. By using one having three or more functional groups, it is easy to lower the adhesive strength after irradiation with energy rays, and the peel performance of the surface protective film tends to be good. The urethane acrylate oligomer usually has 12 functional groups or less.
The urethane acrylate oligomer preferably has a weight average molecular weight of 1000 to 15000, more preferably 1500 to 8500.
The energy beam polymerizable compound (B) is usually blended in an amount of 5 to 200 parts by mass with respect to 100 parts by mass of the acrylic copolymer (A) (main polymer). Is preferably 200 parts by mass, more preferably 70 to 150 parts by mass. By keeping the content of the energy beam polymerizable compound (B) in the above range, the adhesive strength of the pressure-sensitive adhesive layer before energy ray irradiation is appropriately maintained, and the adhesive strength is appropriately reduced by curing with energy rays. Can do.
　エネルギー線硬化型粘着剤組成物としては、Ｘ型とＹ型とを併用した組成物（以下、Ｘ－Ｙ型という）であってもよい。すなわち、アクリル系粘着剤においては、アクリル系重合体（Ａ）に加えてエネルギー線重合性化合物（Ｂ）を含有するとともに、アクリル系共重合体（Ａ）等の少なくとも一部が側鎖に不飽和基を有するエネルギー線硬化型アクリル系共重合体であるものも好ましい態様として使用可能である。Ｘ－Ｙ型を使用することで、粘着剤層の破断強度及び破断伸度が良好となり、表面保護フィルムを剥離する際の被着体への糊残りが減少しやすくなる。
　例えば、Ｘ－Ｙ型である場合に使用されるエネルギー線硬化型アクリル系共重合体は、上記したＸ型で使用されるものと同様のものが使用される。 The energy ray-curable pressure-sensitive adhesive composition may be a composition using both X-type and Y-type (hereinafter referred to as XY type). That is, the acrylic pressure-sensitive adhesive contains the energy beam polymerizable compound (B) in addition to the acrylic polymer (A), and at least a part of the acrylic copolymer (A) is not present in the side chain. What is an energy ray curable acrylic copolymer having a saturated group can also be used as a preferred embodiment. By using the XY type, the breaking strength and breaking elongation of the pressure-sensitive adhesive layer are improved, and the adhesive residue on the adherend when the surface protective film is peeled is easily reduced.
For example, the energy ray curable acrylic copolymer used for the XY type is the same as that used for the X type.
　また、Ｘ－Ｙ型で使用されるエネルギー線重合性化合物（Ｂ）も、上記したＹ型で使用されたものと同様のものが使用され、ウレタンアクリレート系オリゴマーが好ましいが、その際のポリイソシアナートとしては、イソホロンジイソシアナート、１，３－ビス－(イソシアナトメチル)－シクロヘキサン、４，４’－ジシクロヘキシルメタンジイソシアナート等を用いることがより好ましい。また、ウレタンアクリレート中のポリオールユニットを形成するポリオールとしては、ポリプロピレングリコール（ＰＰＧ）、ポリエチレングリコール（ＰＥＧ）、ポリテトラメチレングリコール、ポリカーボネートジオール等が使用されることが好ましく、これらのポリオールの数平均分子量は、３００～２０００が好ましく、５００～１０００が特に好ましい。
　また、ポリオールは、粘着剤層の破断応力及び破断伸度をより良好にするために、２種類以上のポリオールを含んでいることがさらに好ましく、そのポリオールとしては、ＰＰＧとＰＥＧとを含んでいることが特に好ましく、ＰＰＧとＰＥＧのみからなることが最も好ましい。ＰＰＧとＰＥＧのモル比は、９：１～１：９であることが好ましく、９：１～１：４であることがより好ましく、４：１～３：２であることがさらに好ましく、７．５：２．５～６．５：３．５であることが最も好ましい。
　さらに、Ｘ－Ｙ型におけるウレタンアクリレート系オリゴマーとしては、１分子中に（メタ）アクリロイル基を２つ有する２官能基のものが好ましい。２官能基のものを使用することで、剥離性能や粘着性を良好にしつつ、破断強度及び破断伸度を高いものにしやすくなる。
　また、Ｘ－Ｙ型においてエネルギー線重合性化合物（Ｂ）は、アクリル系共重合体（Ａ）（メインポリマー）１００質量部に対して、１～５０質量部であることが好ましく、５～３０質量部であることがより好ましい。 Also, the energy ray polymerizable compound (B) used in the XY type is the same as that used in the Y type described above, and is preferably a urethane acrylate oligomer. It is more preferable to use isophorone diisocyanate, 1,3-bis- (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, etc. Moreover, as a polyol which forms the polyol unit in urethane acrylate, it is preferable to use polypropylene glycol (PPG), polyethylene glycol (PEG), polytetramethylene glycol, polycarbonate diol, etc., and the number average molecular weight of these polyols Is preferably 300 to 2000, particularly preferably 500 to 1000.
Further, the polyol preferably contains two or more kinds of polyols in order to improve the breaking stress and breaking elongation of the pressure-sensitive adhesive layer, and the polyol contains PPG and PEG. It is particularly preferred that it consists only of PPG and PEG. The molar ratio of PPG to PEG is preferably 9: 1 to 1: 9, more preferably 9: 1 to 1: 4, and further preferably 4: 1 to 3: 2. Most preferably, the ratio is from 5: 2.5 to 6.5: 3.5.
Further, the urethane acrylate oligomer in the XY type is preferably a bifunctional group having two (meth) acryloyl groups in one molecule. By using a bifunctional group, it becomes easy to increase the breaking strength and breaking elongation while improving the peeling performance and the adhesiveness.
In the XY type, the energy ray polymerizable compound (B) is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the acrylic copolymer (A) (main polymer). More preferably, it is part by mass.
　粘着剤層は、アクリル系共重合体（Ａ）等のメインポリマーが架橋された架橋構造を有していてもよい。架橋のために粘着剤組成物に含有される架橋剤（Ｃ）としては、有機多価イソシアネート化合物、有機多価エポキシ化合物、有機多価イミン化合物等が挙げられ、これらの中では、有機多価イソシアネート化合物（イソシアネート系架橋剤）が好ましい。 The pressure-sensitive adhesive layer may have a crosslinked structure in which a main polymer such as an acrylic copolymer (A) is crosslinked. Examples of the crosslinking agent (C) contained in the pressure-sensitive adhesive composition for crosslinking include organic polyvalent isocyanate compounds, organic polyvalent epoxy compounds, and organic polyvalent imine compounds. Among these, organic polyvalent isocyanate compounds are exemplified. Isocyanate compounds (isocyanate-based crosslinking agents) are preferred.
　有機多価イソシアネート化合物としては、芳香族多価イソシアネート化合物、脂肪族多価イソシアネート化合物、脂環族多価イソシアネート化合物およびこれらの有機多価イソシアネート化合物の三量体、ならびにこれら有機多価イソシアネート化合物とポリオール化合物とを反応させて得られる末端イソシアネートウレタンプレポリマー等を挙げることができる。 Examples of organic polyvalent isocyanate compounds include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these organic polyvalent isocyanate compounds, and these organic polyvalent isocyanate compounds. Examples thereof include terminal isocyanate urethane prepolymers obtained by reacting with a polyol compound.
　有機多価イソシアネート化合物のさらに具体的な例としては、２，４－トリレンジイソシアネート、２，６－トリレンジイソシアネート、１，３－キシリレンジイソシアネート、１，４－キシレンジイソシアネート、ジフェニルメタン－４，４’－ジイソシアネート、ジフェニルメタン－２，４’－ジイソシアネート、３－メチルジフェニルメタンジイソシアネート、ヘキサメチレンジイソシアネート、イソホロンジイソシアネート、ジシクロヘキシルメタン－４，４’－ジイソシアネート、ジシクロヘキシルメタン－２，４’－ジイソシアネート、トリレンジイソシアネートとトリメチロールプロパンの付加物などが挙げられる。 Specific examples of the organic polyvalent isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4. '-Diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, tolylene diisocyanate Examples include adducts of trimethylolpropane.
　有機多価エポキシ化合物の具体的な例としては、１，３－ビス（Ｎ，Ｎ’－ジグリシジルアミノメチル）シクロヘキサン、Ｎ，Ｎ，Ｎ’，Ｎ’－テトラグリシジル－ｍ－キシリレンジアミン、エチレングリコールジグリシジルエーテル、１，６－ヘキサンジオールジグリシジルエーテル、トリメチロールプロパンジグリシジルエーテル、ジグリシジルアニリン、ジグリシジルアミンなどが挙げられる。 Specific examples of the organic polyvalent epoxy compound include 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, Examples include ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl aniline, and diglycidyl amine.
　有機多価イミン化合物の具体的な例としては、Ｎ，Ｎ’－ジフェニルメタン－４，４’－ビス（１－アジリジンカルボキシアミド）、トリメチロールプロパン－トリ－β－アジリジニルプロピオネート、テトラメチロールメタン－トリ－β－アジリジニルプロピオネートおよびＮ，Ｎ’－トルエン－２，４－ビス（１－アジリジンカルボキシアミド）トリエチレンメラミン等を挙げることができる。 Specific examples of the organic polyvalent imine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetra Mention may be made of methylolmethane-tri-β-aziridinylpropionate and N, N′-toluene-2,4-bis (1-aziridinecarboxyamide) triethylenemelamine.
　架橋剤（Ｃ）の含有量は、アクリル系共重合体（Ａ）（メインポリマー）１００質量部に対して、好ましくは０．０１～２０質量部、より好ましくは０．１～１５質量部、特に好ましくは０．５～８質量部の比率で用いられる。架橋剤（Ｃ）の含有量を上記上限以下とすると、粘着剤層が過度に架橋するのを防止し、適切な粘着力が得られやすくなる。また、架橋剤の使用量を上記下限値以上とすることで、電子部材や光学部材に粘着剤が残着することが防止される。 The content of the crosslinking agent (C) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, with respect to 100 parts by mass of the acrylic copolymer (A) (main polymer). Particularly preferably, it is used in a ratio of 0.5 to 8 parts by mass. When the content of the crosslinking agent (C) is not more than the above upper limit, the pressure-sensitive adhesive layer is prevented from being excessively crosslinked, and appropriate adhesive force is easily obtained. Moreover, by making the usage-amount of a crosslinking agent more than the said lower limit, it is prevented that an adhesive adheres to an electronic member or an optical member.
　また、エネルギー線硬化型粘着剤組成物は、光重合開始剤（Ｄ）を含有することが好ましい。
　光重合開始剤としては、ベンゾイン化合物、アセトフェノン化合物、アシルフォスフィンオキサイド化合物、チタノセン化合物、チオキサントン化合物、パーオキサイド化合物等の光開始剤、アミンやキノン等の光増感剤などが挙げられ、具体的には、１－ヒドロキシシクロヘキシルフェニルケトン、ベンゾイン、ベンゾインメチルエーテル、ベンゾインエチルエーテル、ベンゾインイソプロピルエーテル、ベンジルジフェニルサルファイド、テトラメチルチウラムモノサルファイド、アゾビスイソブチロニトリル、ジベンジル、ジアセチル、β－クロールアンスラキノン、２,４,６－トリメチルベンゾイルジフェニルフォスフィンオキサイドなどが例示できる。光重合開始剤（Ｄ）を配合することで、硬化のためのエネルギー線の照射時間及び照射量を少なくすることができる。
　光重合開始剤（Ｄ）の含有量は、特に限定されないが、アクリル系共重合体（Ａ）（メインポリマー）１００質量部に対して、好ましくは０．１～１０質量部、より好ましくは１～５質量部である。 Moreover, it is preferable that an energy-beam curable adhesive composition contains a photoinitiator (D).
Examples of photopolymerization initiators include photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds, and photosensitizers such as amines and quinones. 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone Examples include 2,4,6-trimethylbenzoyldiphenylphosphine oxide. By mix | blending a photoinitiator (D), the irradiation time and irradiation amount of the energy beam for hardening can be decreased.
The content of the photopolymerization initiator (D) is not particularly limited, but is preferably 0.1 to 10 parts by mass, more preferably 1 with respect to 100 parts by mass of the acrylic copolymer (A) (main polymer). Is 5 parts by mass.
　また、表面保護フィルムの光透過率が５０％未満となるように、粘着剤層が着色されていてもよい。粘着剤層は着色されることにより、表面保護フィルムの視認性が向上するため、例えば人手により表面保護フィルムを後述する剥離シートから容易に剥離しやすくなる。なお、表面保護フィルムの光透過率とは、波長６００ｎｍにおいて株式会社島津製作所製　分光光度計　ＵＶ－３６００により測定されたものである。上記光透過率は、好ましくは１０～４０％程度である。
　粘着剤層を着色するために、粘着剤組成物には、通常、染料、顔料が含有されており、中でも青色染料、青色顔料が含有されることが好ましい。 Further, the pressure-sensitive adhesive layer may be colored so that the light transmittance of the surface protective film is less than 50%. Since the visibility of the surface protective film is improved by coloring the pressure-sensitive adhesive layer, for example, the surface protective film is easily peeled from a release sheet described later by hand. The light transmittance of the surface protective film is measured with a spectrophotometer UV-3600 manufactured by Shimadzu Corporation at a wavelength of 600 nm. The light transmittance is preferably about 10 to 40%.
In order to color the pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition usually contains a dye and a pigment, and among them, a blue dye and a blue pigment are preferably contained.
　また、上述した粘着剤には、酸化防止剤、軟化剤（可塑剤）、劣化防止剤、帯電防止剤、難燃剤、防錆剤、充填剤、シリコーン化合物、シランカップリング剤、連鎖移動剤等の上記成分以外の成分が適宜含有されてもよい。 In addition, the above-mentioned pressure-sensitive adhesives include antioxidants, softeners (plasticizers), deterioration inhibitors, antistatic agents, flame retardants, rust inhibitors, fillers, silicone compounds, silane coupling agents, chain transfer agents, and the like. Components other than the above components may be contained as appropriate.
　また、上記粘着剤層が、エネルギー線硬化型粘着剤組成物からなる粘着剤層である場合、表面保護フィルムはエネルギー線照射前の粘着力が１０００～２００００ｍＮ／２５ｍｍであることが好ましく、４０００～１６０００ｍＮ／２５ｍであることがより好ましい。エネルギー線照射前の粘着力が１０００ｍＮ／２５ｍ以上であることで、表面保護フィルムの光学部材や電子部材に対する接着力が高くなり、その保護性能が良好になる。また、２００００ｍＮ／２５ｍｍ以下とすることで、エネルギー線照射後の粘着力を所望の大きさにしやすくなる。エネルギー線照射前の粘着力は、アルキル（メタ）アクリレートの種類および配合比、架橋剤の使用量等により調整することが可能である。 When the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer made of an energy ray-curable pressure-sensitive adhesive composition, the surface protective film preferably has a pressure-sensitive adhesive force before irradiation with energy rays of 1000 to 20000 mN / 25 mm. More preferably, it is 16000 mN / 25 m. When the adhesive strength before energy beam irradiation is 1000 mN / 25 m or more, the adhesive strength of the surface protective film to the optical member and the electronic member is increased, and the protective performance is improved. Moreover, it becomes easy to make the adhesive force after energy ray irradiation a desired magnitude | size by setting it as 20000 mN / 25mm or less. The adhesive strength before energy beam irradiation can be adjusted by the type and blending ratio of alkyl (meth) acrylate, the amount of crosslinking agent used, and the like.
　また、表面保護フィルムは、エネルギー線照射後の粘着力が０．１～１００ｍＮ／２５ｍｍであることが好ましく、２０～９０ｍＮ／２５ｍｍであることがより好ましい。エネルギー線照射後の粘着力がこのような範囲となることで、エネルギー線照射後、表面保護フィルムを容易に光学部材や電子部材から剥離することが可能になる。
　エネルギー線照射後の粘着力は、エネルギー線重合性化合物（Ｂ）の種類や量、アクリル系共重合体に導入される不飽和基の量により制御できる。 The surface protective film preferably has an adhesive strength of 0.1 to 100 mN / 25 mm, more preferably 20 to 90 mN / 25 mm after energy beam irradiation. When the adhesive force after energy beam irradiation falls within such a range, the surface protective film can be easily peeled off from the optical member or the electronic member after energy beam irradiation.
The adhesive strength after energy beam irradiation can be controlled by the type and amount of the energy beam polymerizable compound (B) and the amount of unsaturated groups introduced into the acrylic copolymer.
　また、粘着剤層のエネルギー線照射前の初期粘着力は、１００００ｍＮ／２５ｍｍ未満であることが好ましい。初期粘着力をこのように比較的低い値とすることで、表面保護フィルムの貼り直しが容易となり、リワーク性が向上する。初期粘着力の下限値は、特に限定されないが、通常、５００ｍＮ／２５ｍｍ以上である。初期粘着力は、３０００～９５００ｍＮ／２５ｍｍであることがより好ましい。
　なお、初期粘着力は、アルキル（メタ）アクリレートの種類および配合比、官能基含有モノマーの種類および配合比、架橋剤の使用量等により調整することが可能である。
　また、上記した粘着力及び初期粘着力の測定方法は、以下に記載した方法に基づいて測定した値である。 Moreover, it is preferable that the initial stage adhesive force before energy beam irradiation of an adhesive layer is less than 10000 mN / 25mm. By setting the initial adhesive force to such a relatively low value, it becomes easy to re-attach the surface protective film, and the reworkability is improved. The lower limit value of the initial adhesive strength is not particularly limited, but is usually 500 mN / 25 mm or more. The initial adhesive strength is more preferably 3000 to 9500 mN / 25 mm.
The initial adhesive strength can be adjusted by the kind and blending ratio of the alkyl (meth) acrylate, the kind and blending ratio of the functional group-containing monomer, the amount of the crosslinking agent used, and the like.
Moreover, the measuring method of the above-mentioned adhesive force and initial stage adhesive force is the value measured based on the method described below.
〔粘着力〕
　表面保護フィルムを２５ｍｍの幅に裁断して試料とし、２３℃、５０％相対湿度の環境下で、２ｋｇローラで被着体であるシリコンウエハのミラー面に貼付する。２３℃５０％相対湿度の環境下に２０分間静置した後、引張速度３００ｍｍ／分、１８０°で剥離した際の粘着力を測定し、エネルギー線照射前の粘着力とする。
　また、２０分間静置後のシリコンウエハに貼付された試料に、紫外線照射装置（リンテック株式会社製ＲＡＤ－２０００ｍ／１２）を用い、窒素雰囲気下にて紫外線を照射する（照度２３０ｍＷ／ｃｍ２、光量１９０ｍＪ／ｃｍ２）。その後、２３℃、５０％相対湿度の環境下で、引張速度３００ｍｍ／分、１８０°で剥離した際の粘着力を測定し、エネルギー線照射後の粘着力とする。
〔初期粘着力〕
　表面保護フィルムを２５ｍｍの幅に裁断して試料とし、２３℃、５０％相対湿度の環境下で、２ｋｇローラで被着体であるシリコンウエハに貼付する。その貼付直後（１分以内）に２３℃、５０％相対湿度の環境下で引張速度３００ｍｍ／分、１８０°で剥離した際の粘着力を測定し、その粘着力を初期粘着力とする。 〔Adhesive force〕
The surface protective film is cut to a width of 25 mm to form a sample, and is attached to the mirror surface of the silicon wafer as an adherend with a 2 kg roller in an environment of 23 ° C. and 50% relative humidity. After standing for 20 minutes in an environment of 23 ° C. and 50% relative humidity, the adhesive strength when peeled at 180 ° at a tensile speed of 300 mm / min is measured to obtain the adhesive strength before energy beam irradiation.
In addition, the sample attached to the silicon wafer after standing for 20 minutes is irradiated with ultraviolet rays in a nitrogen atmosphere (illuminance: 230 mW / cm 2 , using a RAD-2000m / 12 manufactured by Lintec Corporation). Light quantity 190 mJ / cm 2 ). Thereafter, the adhesive force when peeled at 180 ° in a tensile rate of 300 mm / min in an environment of 23 ° C. and 50% relative humidity is measured and set as the adhesive strength after irradiation with energy rays.
[Initial adhesive strength]
The surface protective film is cut into a width of 25 mm to obtain a sample, and is attached to a silicon wafer as an adherend with a 2 kg roller in an environment of 23 ° C. and 50% relative humidity. Immediately after the application (within 1 minute), the adhesive strength when peeled at 180 ° in a tensile rate of 300 mm / min in an environment of 23 ° C. and 50% relative humidity is measured, and the adhesive strength is taken as the initial adhesive strength.
　粘着剤層の厚みは特に限定されず、好ましくは３～５０μｍ、より好ましくは５～３０μｍである。粘着剤層の厚みが上記範囲内にあることで、被着体に対する密着性を高めやすくなる。 The thickness of the pressure-sensitive adhesive layer is not particularly limited, and is preferably 3 to 50 μm, more preferably 5 to 30 μm. It becomes easy to improve the adhesiveness with respect to a to-be-adhered body because the thickness of an adhesive layer exists in the said range.
　また、表面保護フィルムは、支持体の上に粘着剤層を部分的に設けて、支持体の上に粘着部とともに非粘着部を形成してもよい。部分的に粘着剤層を設けた表面保護フィルムを作成するには、スクリーン印刷やインクジェット印刷を行うとよい。粘着部と非粘着部は、ストライプ形状、格子形状、ドット形状、波線を複数並べた形状、市松模様、及び各種の模様を複数並べた形状から選択されるいずれかのパターンで配置されることが好ましく、その他の形状であってもよい。
　なお、粘着剤層が、パターン状に部分的に設けられる場合、そのパターンは、通常、支持体の全面に設けられる。
　さらに、各パターンにおいて、パターンのピッチ（すなわち、隣接する粘着部同士の間の間隔、又は隣接する非粘着部同士の間の間隔）は、好ましくは１０～５００μｍ、より好ましくは１０～３００μｍ、特に好ましくは１０～２５０μｍである。
　すなわち、各ストライプの幅及びストライプの間隔、各波線の幅及び波線と波線の間の間隔、格子をなす各線の幅、及び格子を構成する隣接する線と線の間の間隔、ドット間の間隔並びにドットの幅及び高さ、あるいは、市松模様を構成する各四角形の高さ及び幅は、好ましくは１０～５００μｍ、より好ましくは１０～３００μｍ、特に好ましくは１０～２５０μｍである。 Moreover, a surface protection film may provide an adhesive layer partially on a support body, and may form a non-adhesion part with an adhesion part on a support body. In order to create a surface protective film partially provided with an adhesive layer, screen printing or inkjet printing may be performed. The adhesive portion and the non-adhesive portion may be arranged in any pattern selected from a stripe shape, a lattice shape, a dot shape, a shape in which a plurality of wavy lines are arranged, a checkered pattern, and a shape in which various patterns are arranged in a plurality. Other shapes may be preferable.
In addition, when an adhesive layer is partially provided in pattern shape, the pattern is normally provided in the whole surface of a support body.
Further, in each pattern, the pattern pitch (that is, the interval between adjacent adhesive portions or the interval between adjacent non-adhesive portions) is preferably 10 to 500 μm, more preferably 10 to 300 μm, particularly The thickness is preferably 10 to 250 μm.
That is, the width of each stripe and the interval between stripes, the width of each wavy line and the interval between wavy lines, the width of each line forming the lattice, the interval between adjacent lines constituting the lattice, the interval between dots The width and height of the dots, or the height and width of each square constituting the checkered pattern is preferably 10 to 500 μm, more preferably 10 to 300 μm, and particularly preferably 10 to 250 μm.
　また、表面保護フィルムは、被着体の表面に接着する前に、予め粘着剤層の一部にエネルギー線を照射することにより硬化しているものであってもよい。粘着剤層の一部がエネルギー線の照射により一部硬化されると、表面保護フィルムの被着体の表面に接着する接着面は、エネルギー線が照射されず粘着力が高いままである強粘着部と、エネルギー線が照射されて硬化し、強粘着部よりも粘着力が低い弱粘着部とを備えることになる。
　強粘着部と弱粘着部は、上記した粘着部と非粘着部と同様に、パターン状に配置されることが好ましい。なお、強粘着部と弱粘着部のパターンの詳細は、上記した粘着部と非粘着部のパターンと同様であるので、その説明は省略する。
　粘着剤層の部分硬化は、特に限定されないが、例えば弱粘着部に一致した形状の開口部を有するマスク、あるいは、強粘着部に一致した形状の遮光部を有する遮光部材を介して、公知の照射装置からエネルギー線を粘着剤層に照射することで行うとよい。エネルギー線は、支持体側から支持体を介して、粘着剤層に照射してもよいし、支持体の反対側から照射してもよい。
　なお、粘着剤層が部分的に硬化されている場合であっても、後述するように、表面保護フィルムを光学部材又は電子部材から剥離する前に、被着体に貼付された表面保護フィルムにエネルギー線を照射することが好ましい。
　表面保護フィルムに粘着部と非粘着部、又は強粘着部と弱粘着部を設け、かつその粘着部と非粘着部の面積の割合、又は強粘着部と弱粘着部の面積の割合を適宜調整することで、表面保護フィルムの粘着力を適宜調整可能である。 Further, the surface protective film may be cured in advance by irradiating a part of the pressure-sensitive adhesive layer with energy rays before adhering to the surface of the adherend. When part of the pressure-sensitive adhesive layer is partially cured by irradiation with energy rays, the adhesive surface that adheres to the surface of the adherend of the surface protective film is strongly adhered to the surface without being irradiated with energy rays. Part and an energy ray are irradiated and hardened | cured, and the weak adhesive part whose adhesive force is lower than a strong adhesive part is provided.
The strong adhesive portion and the weak adhesive portion are preferably arranged in a pattern like the above-described adhesive portion and non-adhesive portion. Note that the details of the pattern of the strong adhesive portion and the weak adhesive portion are the same as the pattern of the adhesive portion and the non-adhesive portion described above, and thus the description thereof is omitted.
The partial curing of the pressure-sensitive adhesive layer is not particularly limited, but for example, it is publicly known through a mask having an opening having a shape matching the weakly-adhesive part or a light-shielding member having a light-shielding part having a shape corresponding to the strong adhesive part. It is good to carry out by irradiating an adhesive layer with an energy ray from an irradiation apparatus. The energy ray may be applied to the pressure-sensitive adhesive layer from the support side through the support, or may be applied from the opposite side of the support.
Even when the pressure-sensitive adhesive layer is partially cured, as described later, before the surface protective film is peeled off from the optical member or the electronic member, the surface protective film attached to the adherend is applied to the surface protective film. It is preferable to irradiate energy rays.
Adhesive part and non-adhesive part or strong adhesive part and weak adhesive part are provided on the surface protective film, and the ratio of the area of the adhesive part and non-adhesive part, or the ratio of the area of strong adhesive part and weak adhesive part is adjusted appropriately By doing so, the adhesive force of the surface protective film can be appropriately adjusted.
＜易接着層＞
　上記支持体は、各層の層間の密着性を向上させるために、基材と緩衝層との間、基材と樹脂層との間、又はその両方に易接着層を有していてもよい。
　また、支持体は、粘着剤層との間の密着性を向上させるために、粘着剤層に接する面（支持体が樹脂層又は基材を有する場合は、そのいずれかの表面）との間に易接着層を有していてもよい。
　易接着層を形成する易接着層形成用組成物としては、特に限定されないが、例えば、ポリエステル系樹脂、ウレタン系樹脂、ポリエステルウレタン系樹脂、アクリル系樹脂等を含む組成物が挙げられる。
　なお、当該易接着層形成用組成物には、必要に応じて、架橋剤、光重合開始剤、酸化防止剤、軟化剤（可塑剤）、充填剤、防錆剤、顔料、染料等を含有してもよい。
　易接着層の厚さとしては、好ましくは０．０１～１０μｍ、より好ましくは０．０３～５μｍである。 <Easily adhesive layer>
The said support body may have an easily bonding layer between a base material and a buffer layer, between a base material and a resin layer, or both in order to improve the adhesiveness between the layers of each layer.
Further, in order to improve the adhesion between the support and the pressure-sensitive adhesive layer, the surface is in contact with the surface of the pressure-sensitive adhesive layer (if the support has a resin layer or a substrate, any surface thereof). May have an easy-adhesion layer.
Although it does not specifically limit as a composition for easy-adhesion layer formation which forms an easy-adhesion layer, For example, the composition containing a polyester-type resin, a urethane-type resin, a polyester urethane-type resin, an acrylic resin etc. is mentioned.
The easy-adhesion layer-forming composition contains a crosslinking agent, a photopolymerization initiator, an antioxidant, a softening agent (plasticizer), a filler, a rust inhibitor, a pigment, a dye, and the like as necessary. May be.
The thickness of the easy adhesion layer is preferably 0.01 to 10 μm, more preferably 0.03 to 5 μm.
＜剥離シート＞
　本発明の表面保護フィルムの粘着剤層側は、剥離シートが貼付されて、剥離シートにより保護されていてもよい。両面剥離処理をされた剥離シートや、片面剥離処理された剥離シート等が用いられ、剥離シート用基材の表面上に剥離剤を塗布したもの等が挙げられる。
　剥離シート用基材としては、樹脂フィルムが好ましく、当該樹脂フィルムを構成する樹脂としては、例えば、ポリエチレンテレフタレート樹脂、ポリブチレンテレフタレート樹脂、ポリエチレンナフタレート樹脂等のポリエステル樹脂フィルム、ポリプロピレン樹脂、ポリエチレン樹脂等のポリオレフィン樹脂等が挙げられる。
　剥離剤としては、例えば、シリコーン系樹脂、オレフィン系樹脂、イソプレン系樹脂、ブタジエン系樹脂等のゴム系エラストマー、長鎖アルキル系樹脂、アルキド系樹脂、フッ素系樹脂等が挙げられる。
　剥離シートの厚さは、特に制限ないが、好ましくは１０～２００μｍ、より好ましくは２０～１５０μｍである。 <Peeling sheet>
The pressure-sensitive adhesive layer side of the surface protective film of the present invention may be protected with a release sheet by attaching a release sheet. A release sheet that has been subjected to a double-sided release treatment, a release sheet that has been subjected to a single-sided release treatment, or the like is used.
As the base for the release sheet, a resin film is preferable, and examples of the resin constituting the resin film include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, polypropylene resin, polyethylene resin, and the like. Polyolefin resin and the like.
Examples of the release agent include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long chain alkyl resins, alkyd resins, and fluorine resins.
The thickness of the release sheet is not particularly limited, but is preferably 10 to 200 μm, more preferably 20 to 150 μm.
　表面保護フィルムのフィルム面積は、１００ｍｍ２以下であることが好ましく、より好ましくは１０～８０ｍｍ２程度である。表面保護フィルムは、光学部材及び電子部材に応じてサイズが小さくなる。一般的に、フィルムサイズが小さくなると貼り付けや剥離といった作業が難しくなる。本発明の表面保護フィルムは、上述したように剥離性能が良好であるため、手作業でも剥離しやすい。また、表面保護フィルムは、その形状は限定されないが、例えば、円形、環状形、正方形、矩形等に加工される。
　なお、表面保護フィルムを所定のフィルム面積ないし所定の形状に加工する際、後述するように、通常、抜き加工を行う。 The film area of the surface protective film is preferably 100 mm 2 or less, more preferably about 10 to 80 mm 2 . A surface protection film becomes small according to an optical member and an electronic member. Generally, when the film size is reduced, operations such as pasting and peeling become difficult. Since the surface protective film of the present invention has good peeling performance as described above, it is easy to peel off even by manual work. The shape of the surface protective film is not limited, but is processed into, for example, a circular shape, an annular shape, a square shape, a rectangular shape, or the like.
In addition, when processing a surface protection film into a predetermined film area thru | or a predetermined shape, a punching process is usually performed as described later.
＜表面保護フィルムの製造方法＞
　本発明の表面保護フィルムの製造方法としては、特に制限はなく、公知の方法により製造することができる。
　例えば、基材の両面それぞれに、剥離シート上に設けた緩衝層と、剥離シート上に設けた粘着剤層とを貼り合わせて製造することができる。また、基材の表面上に直接緩衝層を設けて支持体を作製し、支持体上に、粘着剤層を設けることができる。
　また、剥離シート上に設けた緩衝層と剥離シート上に設けた粘着剤層とを互いに貼り合わせて製造することもできる。 <Method for producing surface protective film>
There is no restriction | limiting in particular as a manufacturing method of the surface protection film of this invention, It can manufacture by a well-known method.
For example, the buffer layer provided on the release sheet and the pressure-sensitive adhesive layer provided on the release sheet can be bonded to each side of the substrate. Moreover, a buffer layer can be provided directly on the surface of the substrate to produce a support, and the pressure-sensitive adhesive layer can be provided on the support.
In addition, the buffer layer provided on the release sheet and the pressure-sensitive adhesive layer provided on the release sheet may be bonded to each other.
　剥離シート又は基材上に緩衝層を形成する方法としては、剥離シート又は基材上に緩衝層形成用組成物を、公知の塗布方法にて、直接塗布して塗布膜を形成することができる。また、塗布膜を乾燥及び／又はエネルギー線を照射することで、緩衝層を形成することができる。
　塗布方法としては、例えば、スピンコート法、スプレーコート法、バーコート法、ナイフコート法、ロールコート法、ブレードコート法、ダイコート法、グラビアコート法等が挙げられる。 As a method for forming a buffer layer on a release sheet or substrate, a coating film can be formed by directly applying the buffer layer forming composition on the release sheet or substrate by a known application method. . Moreover, a buffer layer can be formed by drying a coating film and / or irradiating energy rays.
Examples of the coating method include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.
　また、塗布性を向上させるために、緩衝層形成用組成物、又は緩衝層形成用樹脂フィルムの原料に対して有機溶媒を配合し、溶液の形態として、剥離シート上に塗布してもよい。
　用いる有機溶媒としては、例えば、メチルエチルケトン、アセトン、酢酸エチル、テトラヒドロフラン、ジオキサン、シクロヘキサン、ｎ－ヘキサン、トルエン、キシレン、ｎ－プロパノール、イソプロパノール等が挙げられる。
　なお、これらの有機溶媒は、組成物中に含まれる各成分の合成時に使用された有機溶媒をそのまま用いてもよいし、それ以外の１種以上の有機溶媒を加えてもよい。 Moreover, in order to improve applicability | paintability, an organic solvent may be mix | blended with the raw material of the composition for buffer layer formation, or the resin film for buffer layer formation, and you may apply | coat on a peeling sheet as a solution form.
Examples of the organic solvent to be used include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol and the like.
In addition, as for these organic solvents, the organic solvent used at the time of the synthesis | combination of each component contained in a composition may be used as it is, and 1 or more types of other organic solvents may be added.
　塗布膜を形成する緩衝層形成用組成物が、エネルギー線重合性化合物を含む緩衝層形成用組成物の場合は、当該塗布膜に対して、エネルギー線を照射することで硬化させ、緩衝層を形成することができる。
　緩衝層の硬化処理は、一度に完全に硬化させてもよいし、複数回に分けて硬化させてもよい。つまり、剥離シート上の塗布膜を完全に硬化させて緩衝層を形成した後に基材に貼り合わせてもよく、当該塗布膜を完全に硬化させずに半硬化の状態の緩衝層形成膜を形成し、当該緩衝層形成膜を基材に貼り合わせた後、再度エネルギー線を照射して完全に硬化させて緩衝層を形成してもよい。
　または、基材上に直接当該塗布膜を完全に硬化させずに半硬化の状態の緩衝層形成膜を形成した後、再度エネルギー線を照射して完全に硬化させて緩衝層を形成してもよい。 When the composition for forming a buffer layer for forming the coating film is a composition for forming a buffer layer containing an energy beam polymerizable compound, the coating film is cured by irradiating energy rays to the buffer layer. Can be formed.
The buffer layer may be cured completely at once, or may be cured in multiple steps. In other words, after the coating film on the release sheet is completely cured to form a buffer layer, it may be bonded to the base material, and a semi-cured buffer layer forming film is formed without completely curing the coating film. Then, after the buffer layer forming film is bonded to the base material, the buffer layer may be formed by irradiating energy rays again to be completely cured.
Or, after forming the buffer layer forming film in a semi-cured state without completely curing the coating film directly on the substrate, the buffer layer may be formed by irradiating energy rays again and completely curing Good.
　当該硬化処理で照射するエネルギー線としては、紫外線が好ましい。
　エネルギー線の照射量は、エネルギー線の種類によって適宜変更される。例えば、紫外線を用いる場合、照射する紫外線の照度は、好ましくは５０～５００ｍＷ／ｃｍ２、より好ましくは１００～３４０ｍＷ／ｃｍ２であり、紫外線の照射量は、好ましくは８０～２５００ｍＪ／ｃｍ２、より好ましくは１００～２０００ｍＪ／ｃｍ２である。 As an energy ray irradiated by the said hardening process, an ultraviolet-ray is preferable.
The irradiation amount of energy rays is appropriately changed depending on the type of energy rays. For example, when ultraviolet rays are used, the illuminance of the irradiated ultraviolet rays is preferably 50 to 500 mW / cm 2 , more preferably 100 to 340 mW / cm 2 , and the irradiation amount of ultraviolet rays is preferably 80 to 2500 mJ / cm 2 , More preferably, it is 100 to 2000 mJ / cm 2 .
　また、緩衝層として緩衝層用樹脂フィルムを用いる場合は、上記の塗布法の他、一般的な押出ラミネート加工を用いて緩衝層を形成することができる。また、予め成形された緩衝層用樹脂フィルムを、接着剤を用いて基材用樹脂フィルムと貼り合せることもできる。 Moreover, when using the resin film for buffer layers as a buffer layer, a buffer layer can be formed using a general extrusion laminating process other than said coating method. Moreover, the resin film for buffer layers shape | molded previously can also be bonded together with the resin film for base materials using an adhesive agent.
　粘着剤層を形成する方法は、特に限定されないが、必要に応じ適当な溶剤で希釈したエネルギー線硬化型粘着剤組成物を、剥離シート上に所定の乾燥膜厚になるように塗布し、その後乾燥して粘着剤層を形成した後、粘着剤層に基材又は支持体を貼り合わせて形成すればよい。また、必要に応じ適当な溶剤で希釈したエネルギー線硬化型粘着剤組成物を、基材又は支持体に直接塗布し、その後乾燥して粘着剤層を形成してもよい。 The method for forming the pressure-sensitive adhesive layer is not particularly limited, but an energy ray-curable pressure-sensitive adhesive composition diluted with an appropriate solvent as necessary is applied on the release sheet so as to have a predetermined dry film thickness, and thereafter After drying to form a pressure-sensitive adhesive layer, a base material or a support may be bonded to the pressure-sensitive adhesive layer. Moreover, the energy ray-curable pressure-sensitive adhesive composition diluted with an appropriate solvent as required may be directly applied to a substrate or a support and then dried to form a pressure-sensitive adhesive layer.
　また、表面保護フィルムを所定のフィルム面積に加工する際に、主に、抜き刃を使用した加工（抜き加工）を行うことがある。この抜き加工では、通常、支持体の粘着剤層が設けられる面とは反対側の面（すなわち、緩衝層が設けられる面）から抜き刃が入れられる。本発明の表面保護フィルムを用いることで、表面保護フィルムの抜き刃を当てる側の面に、上記緩衝層が存在するため、抜き加工時に発生する抜き刃の滑り等を抑制でき、加工精度を向上させることができる。抜き加工は、例えば剥離シート上に形成された粘着剤層及び支持体の積層体に対して行えばよい。この抜き加工により、表面保護フィルムの形状を上記したように円形等の所定の形状にする。
　また、任意のタイミングで型押し等により、表面保護フィルムに適宜凹凸を形成してもよい。 Moreover, when processing a surface protection film into a predetermined film area, the process (punching process) which uses a punching blade may be mainly performed. In this punching process, the punching blade is usually inserted from the surface opposite to the surface on which the pressure-sensitive adhesive layer of the support is provided (that is, the surface on which the buffer layer is provided). By using the surface protective film of the present invention, since the buffer layer is present on the surface of the surface protective film on the side where the punching blade is applied, slippage of the punching blade that occurs during the punching process can be suppressed, and processing accuracy is improved. Can be made. For example, the punching process may be performed on a laminate of the pressure-sensitive adhesive layer and the support formed on the release sheet. By this punching process, the shape of the surface protection film is changed to a predetermined shape such as a circle as described above.
Moreover, you may form an unevenness | corrugation suitably in a surface protection film by stamping etc. at arbitrary timings.
［光学部材又は電子部材］
　本発明の表面保護フィルムによって保護される光学部材又は電子部材としては、１又は２以上のレンズとＣＣＤ、ＣＭＯＳ等の撮像センサが筺体又はパッケージ内部に収納された撮像モジュール；複数のレンズがレンズ鏡筒に保持され、必要に応じて筺体又はパッケージ内に収納されたレンズユニット；ＬＥＤ等の発光素子を有する発光素子ユニット；バイブレーター等のモーターユニット；通信モジュール、センサーモジュール等が挙げられる。これら光学部材や電子部材は、基板等の他の部材に取り付けられて使用される部材であることが好ましい。 [Optical member or electronic member]
As an optical member or an electronic member protected by the surface protective film of the present invention, an imaging module in which one or more lenses and an imaging sensor such as a CCD or CMOS are housed in a casing or a package; a plurality of lenses is a lens mirror Examples include a lens unit held in a tube and housed in a housing or a package as necessary; a light emitting element unit having a light emitting element such as an LED; a motor unit such as a vibrator; a communication module, a sensor module, and the like. These optical members and electronic members are preferably members that are used by being attached to other members such as a substrate.
　なお、光学部材とは、光を受光若しくは発光し、または光を伝送する光学部品を備えるものをいい、上記のうち撮像モジュール、レンズユニット、発光素子ユニット、光信号を送信又は受信する通信モジュール、光センサーモジュール等が光学部材の具体例として挙げられる。また、電子部材とは、通常、電気回路の少なくとも一部を構成し、電気信号を送信又は受信する電子部品、電気信号を処理する電子部品、電気信号や電力により作動する電子部品等を備えるものが挙げられ、上記のうち撮像モジュール、発光素子ユニット、バイブレーター等のモーターユニット、電気信号を送信又は受信する通信モジュール、各種センサーモジュール等が電子部材の具体例として挙げられる。なお、光信号を送信又は受信する通信モジュールや光センサーモジュール、撮像モジュール及び発光素子ユニット等は、通常、電子部材であるとともに、光学部材でもある部材である。
　また、光学部材や電子部材は、例えば上記電子部品や光学部品がパッケージや筐体内部に収納され、あるいは支持部材に支持されたものであることが好ましい。また、電子部品や光学部品の一部が表面に露出させたものであることが好ましく、表面保護フィルムは例えば、その露出した部品を保護するために使用される。 The optical member refers to an optical component that receives or emits light, or includes an optical component that transmits light. Among the above, an imaging module, a lens unit, a light emitting element unit, a communication module that transmits or receives an optical signal, An example of the optical member is an optical sensor module. The electronic member usually includes at least a part of an electric circuit and includes an electronic component that transmits or receives an electric signal, an electronic component that processes an electric signal, an electronic component that operates by an electric signal or electric power, and the like. Among them, a motor unit such as an imaging module, a light emitting element unit, and a vibrator, a communication module that transmits or receives an electrical signal, various sensor modules, and the like are specific examples of the electronic member. Note that a communication module, an optical sensor module, an imaging module, a light emitting element unit, and the like that transmit or receive optical signals are members that are both electronic members and optical members.
Moreover, it is preferable that the optical member or the electronic member is, for example, one in which the electronic component or the optical component is housed in a package or a housing or supported by a support member. Moreover, it is preferable that a part of electronic component or optical component is exposed on the surface, and the surface protection film is used, for example, to protect the exposed component.
［表面保護フィルムの使用方法］
　本発明の表面保護フィルムは、光学部材又は電子部材の表面に貼付してその表面を保護するために使用されるものである。具体的には、表面保護フィルムが貼付された光学部材又は電子部材（以下、単に表面保護フィルム付き部材ともいう）は、加工され、他の部材に取り付けられ、検査され、又は搬送等される。表面保護フィルムは、これらの工程において光学部材又は電子部材の表面を保護する。また、表面保護フィルムは、これらの工程が終わり、表面保護の必要がなくなった時点で、エネルギー線が照射され、粘着力を低下させた後、光学部材又は電子部材から剥離される。
　なお、表面保護フィルムの貼り付け及び剥離は、通常、手作業で行われる。その際、本発明の表面保護フィルムを用いることで、光学部材又は電子部材の表面に貼り付けする時に、貼り付け位置のずれが生じにくくなるため、貼り直しの頻度が低減される。また、一度貼り付けした表面保護フィルムを、被着体から剥離する時にも過度な負荷をかけずに剥離することができるため、被着体である光学部材や電子部材を痛めてしまう（歪を起こす、傷が付く等）ことを防止することができる。
　なお、表面保護フィルム付き部材は、上記した加工、取り付け、検査、又は搬送等の工程において加熱されてもよい。その際の加熱温度は特に限定されないが、６０～２００℃程度、好ましくは７０～１５０℃程度である。粘着剤層は、加熱されることにより粘着力が高くなることがある。本発明の表面保護フィルムの粘着剤層に、エネルギー線硬化型粘着剤組成物を用いた場合は、加熱により粘着力が高くなっても、その後、エネルギー線を照射することで粘着力を低下させることが可能であるため、表面保護フィルムを剥離する際の剥離不良や糊残り等が起こりにくくなる。 [Usage of surface protection film]
The surface protective film of this invention is used in order to stick on the surface of an optical member or an electronic member, and to protect the surface. Specifically, an optical member or an electronic member (hereinafter also simply referred to as a member with a surface protective film) to which a surface protective film is attached is processed, attached to another member, inspected, transported, or the like. The surface protective film protects the surface of the optical member or the electronic member in these steps. The surface protective film is peeled off from the optical member or the electronic member after being irradiated with energy rays and reducing the adhesive force when these steps are finished and the surface protection is no longer necessary.
In addition, sticking and peeling of a surface protection film are normally performed manually. At that time, by using the surface protective film of the present invention, it is difficult to cause a shift in the attaching position when attaching to the surface of the optical member or the electronic member, so that the frequency of reattaching is reduced. In addition, since the surface protective film once pasted can be peeled off without applying an excessive load even when peeled off from the adherend, it damages the optical member or electronic member that is the adherend (distortion is distorted). Can be prevented.
In addition, the member with a surface protective film may be heated in steps such as the above-described processing, attachment, inspection, or conveyance. The heating temperature at that time is not particularly limited, but is about 60 to 200 ° C., preferably about 70 to 150 ° C. The pressure-sensitive adhesive layer may become highly adhesive when heated. When the energy ray-curable pressure-sensitive adhesive composition is used for the pressure-sensitive adhesive layer of the surface protective film of the present invention, even if the pressure-sensitive adhesive force is increased by heating, the pressure-sensitive adhesive force is reduced by irradiating energy rays thereafter. Therefore, it is difficult for peeling failure or adhesive residue to occur when the surface protective film is peeled off.
　表面保護フィルムが貼付された光学部材又は電子部材（表面保護フィルム付き部材）は、例えば接着剤により基板等の他の部材に取り付けられることが好ましい。この際、接着剤は熱硬化性のものが使用され、その接着剤を硬化させるために、表面保護フィルム付き部材は、上記したように通常６０～２００℃以上、好ましくは７０～１５０℃程度で加熱されることが好ましい。その後、表面保護が不要になると、表面保護フィルムにエネルギー線が照射され粘着力が低下させられた後に、表面保護フィルムが光学部材又は電子部材から剥離される。 It is preferable that the optical member or the electronic member (the member with the surface protective film) to which the surface protective film is attached is attached to another member such as a substrate with an adhesive, for example. At this time, a thermosetting adhesive is used, and in order to cure the adhesive, the member with a surface protective film is usually at a temperature of 60 to 200 ° C. or higher, preferably about 70 to 150 ° C. as described above. Heating is preferred. Thereafter, when the surface protection is unnecessary, the surface protection film is peeled from the optical member or the electronic member after the surface protection film is irradiated with energy rays and the adhesive force is reduced.
　また、表面保護フィルムは、上記した光学部材又は電子部材の中では、撮像モジュール用の表面保護フィルムとして使用されることが特に好ましい。
　撮像モジュールは、通常、その一面に外部からの光を受光し、その光をモジュール内部のレンズを介して撮像素子に導くための受光部が設けられる。受光部は、撮像モジュールの一面の一部（例えば、中央）に設けられ、ガラスや透明樹脂からなる。表面保護フィルムは、撮像モジュールの受光部が設けられた一面に、受光部を覆うように貼付されることが好ましい。表面保護フィルムは、エネルギー線照射前には、受光部、及び受光部周囲の筺体又はパッケージの表面に高い密着力で接着するため、撮像モジュールの一面に設けられた受光部を適切に保護することが可能である。また、表面保護フィルムは、エネルギー線照射後には、粘着力が低下するので、撮像モジュールから容易に剥離することが可能であり、受光部等に糊残りが生じるのが防止される。
　なお、表面保護フィルムが貼付された撮像モジュールは、上記したように、熱硬化性接着剤の硬化のために加熱されて基板等の他の部材に取り付けられることが好ましい。 Further, the surface protective film is particularly preferably used as a surface protective film for an imaging module in the above-described optical member or electronic member.
The imaging module is usually provided with a light receiving portion for receiving light from the outside on one surface and guiding the light to the imaging device via a lens inside the module. The light receiving unit is provided on a part (for example, the center) of one surface of the imaging module and is made of glass or transparent resin. The surface protective film is preferably attached to one surface of the imaging module where the light receiving part is provided so as to cover the light receiving part. Since the surface protective film adheres to the surface of the light receiving unit and the casing or package around the light receiving unit with high adhesive force before irradiation with energy rays, the light receiving unit provided on one surface of the imaging module should be appropriately protected. Is possible. Moreover, since the adhesive strength of the surface protective film is reduced after irradiation with energy rays, the surface protective film can be easily peeled off from the imaging module, and it is possible to prevent adhesive residue from being generated in the light receiving portion and the like.
In addition, as above-mentioned, it is preferable that the imaging module with which the surface protective film was stuck is heated for hardening of a thermosetting adhesive, and is attached to other members, such as a board | substrate.
　以下、実施例に基づき本発明をさらに詳細に説明するが、本発明はこれらの例によって制限されるものではない。 Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.
　本発明における測定方法及び評価方法は以下のとおりである。
［測定方法］
＜原料の重量平均分子量（Ｍｗ）＞
　ゲル浸透クロマトグラフ装置を用いて、下記の条件下で測定し、標準ポリスチレン換算にて測定した値を用いた。
（測定条件）
測定装置：製品名「ＨＬＣ－８２２０ＧＰＣ」、東ソー株式会社製）
カラム：製品名「ＴＳＫＧｅｌ ＳｕｐｅｒＨＺＭ-Ｍ」、東ソー株式会社製）
展開溶媒：テトラヒドロフラン
カラム温度：４０℃
流速：１．０ｍＬ／ｍｉｎ
＜支持体の剛軟度＞
　ＪＩＳ　Ｌ　１９１３に準ずる方法にて、支持体のＭＤ方向とＴＤ方向、それぞれについて測定を行った。ただし、４５°カンチレバー形試験機を使用し、支持体を２０ｍｍ×１５０ｍｍの試験片にカットした。また、測定に用いた試験片は、ＭＤ方向とＴＤ方向で各２枚ずつ準備した。なお、ここで、ＭＤ方向の試験片とは、試験片の長手方向が支持体のＭＤ方向であることを表す。
　各試験片１枚あたり、曲げ長さ（ｍＮ・ｃｍ）について、表面で２回（両端）、裏面で２回（両端）の合計４回の測定を行った。当該４回分の測定結果について平均値を算出した。ＴＤ方向についても、同様に測定を行った。
　ＭＤ方向の試験片２枚分の曲げ長さの測定値と、測定に用いた試験片の単位面積当たりの質量（ｇ／ｍ２）とから、ＪＩＳ　Ｌ　１９１３に記載された計算式を用いてＭＤ剛軟度を算出した。ＴＤ方向についても同様に、試験片２枚分の曲げ長さの測定値を用いて、ＴＤ剛軟度を算出した。
　算出したＭＤ剛軟度とＴＤ剛軟度との値を平均して、支持体の剛軟度（ｍＮ・ｃｍ）とした。
＜緩衝層の押し込み深さ（Ｚ）の測定＞
　ダイナミック微小硬度計（島津製作所（株）製、製品名「ＤＵＨ－Ｗ２０１Ｓ」）、及び圧子として、先端曲率半径１００ｎｍ、稜間角１１５°の三角錐形状圧子を使用し、２３℃、５０％ＲＨ（相対湿度）の環境下で測定した。
　具体的には、ダイナミック微小硬度計のガラスプレート上に、作製した表面保護フィルムの緩衝層が表出するように設置し、当該緩衝層に対して、上記三角錐形状圧子の先端を１０μｍ／分の速度で押し込み、圧縮荷重が２ｍＮに到達した際の押し込み深さ（Ｚ）の測定を行った。 The measurement method and evaluation method in the present invention are as follows.
[Measuring method]
<Weight average molecular weight of raw material (Mw)>
Using a gel permeation chromatograph, measurement was performed under the following conditions, and values measured in terms of standard polystyrene were used.
(Measurement condition)
Measuring device: Product name “HLC-8220GPC”, manufactured by Tosoh Corporation)
Column: Product name “TSKGel SuperHZM-M” manufactured by Tosoh Corporation)
Developing solvent: Tetrahydrofuran Column temperature: 40 ° C
Flow rate: 1.0 mL / min
<Bending softness of support>
Measurements were performed in the MD direction and TD direction of the support by a method according to JIS L 1913. However, a 45 ° cantilever type tester was used, and the support was cut into 20 mm × 150 mm test pieces. Two test pieces used for the measurement were prepared in each of the MD direction and the TD direction. Here, the test piece in the MD direction means that the longitudinal direction of the test piece is the MD direction of the support.
For each test piece, the bending length (mN · cm) was measured four times in total, twice on the front surface (both ends) and twice on the back surface (both ends). The average value was calculated for the measurement results for the four times. The same measurement was performed for the TD direction.
From the measured value of the bending length of two test pieces in the MD direction and the mass per unit area (g / m 2 ) of the test piece used for the measurement, the calculation formula described in JIS L 1913 is used. MD bending resistance was calculated. Similarly, in the TD direction, the TD bending resistance was calculated using the measurement values of the bending lengths of two test pieces.
The calculated values of MD bending resistance and TD bending resistance were averaged to obtain the bending resistance (mN · cm) of the support.
<Measurement of indentation depth (Z) of buffer layer>
A dynamic microhardness meter (manufactured by Shimadzu Corporation, product name “DUH-W201S”) and a triangular pyramid indenter with a tip radius of curvature of 100 nm and a ridge angle of 115 ° are used as an indenter at 23 ° C. and 50% RH. Measurement was performed under an environment of (relative humidity).
Specifically, it is placed on the glass plate of the dynamic microhardness meter so that the buffer layer of the produced surface protective film is exposed, and the tip of the triangular pyramid-shaped indenter is 10 μm / min with respect to the buffer layer. The indentation depth (Z) was measured when the compression load reached 2 mN.
［表面保護フィルムの評価方法］
＜抜き加工精度＞
　表面保護フィルムを、支持体側から抜き刃を入れて、抜き加工を行った。抜きサイズは直径５ｍｍの円形とした。抜き加工を行った後の表面保護フィルムについて、Ｘ方向とＸ方向と直交するＹ方向との直径を測定し、以下の基準にて評価した。
Ａ：Ｘ方向、及びＹ方向の直径が、５±０．１ｍｍ以内
Ｂ：Ｘ方向、又はＹ方向の直径が、５±０．１ｍｍを超える
＜作業性＞
　表面保護フィルムを直径５ｍｍの円形に加工した。この表面保護フィルムをピンセットを用いて剥離シートから剥離し、被着体である撮像モジュールに貼り合わせた。また、ＵＶ照射後にピンセットを用いて表面保護フィルムを撮像モジュールから剥離して、その作業性を以下の基準で評価した。
Ａ：剥離シートから容易に剥離でき、撮像モジュールへの貼り合わせが、ミスなく容易に行えた。さらに、ＵＶ照射後の剥離も容易に行えた。
Ｂ：剥離シートからの剥離に時間を要し、撮像モジュールへの貼り合わせにも時間を要したが、ＵＶ照射後の剥離は容易に行えた。
Ｃ：剥離シートから容易に剥離でき、撮像モジュールへの貼り合わせが、ミスなく容易に行えたが、ＵＶ照射後の剥離に時間を要した。 [Method for evaluating surface protective film]
<Punching accuracy>
The surface protective film was punched by inserting a punching blade from the support side. The punching size was a circle with a diameter of 5 mm. About the surface protection film after performing a punching process, the diameter of the X direction and the Y direction orthogonal to X direction was measured, and the following references | standards evaluated.
A: Diameter in X direction and Y direction is within 5 ± 0.1 mm B: Diameter in X direction or Y direction exceeds 5 ± 0.1 mm <Workability>
The surface protective film was processed into a circle having a diameter of 5 mm. This surface protective film was peeled off from the release sheet using tweezers, and was bonded to an imaging module as an adherend. Moreover, the surface protection film was peeled off from the imaging module using tweezers after UV irradiation, and the workability was evaluated according to the following criteria.
A: It was easy to peel off from the release sheet, and the attachment to the imaging module could be easily performed without mistake. Further, peeling after UV irradiation could be easily performed.
B: Although time was required for peeling from the release sheet and time was required for bonding to the imaging module, peeling after UV irradiation was easily performed.
C: The film could be easily peeled off from the release sheet, and could be easily attached to the imaging module without any mistake, but it took time to peel off after UV irradiation.
［製造例１］
（ウレタンアクリレート系オリゴマー（ＵＡ－１）の合成）
　ポリエステルジオールと、イソホロンジイソシアネートを反応させて得られた末端イソシアネートウレタンプレポリマーに、２－ヒドロキシエチルアクリレートを反応させて、重量平均分子量（Ｍｗ）５０００の２官能のウレタンアクリレート系オリゴマー（ＵＡ－１）を得た。 [Production Example 1]
(Synthesis of urethane acrylate oligomer (UA-1))
A bifunctional urethane acrylate oligomer (UA-1) having a weight average molecular weight (Mw) of 5000 is reacted with a terminal isocyanate urethane prepolymer obtained by reacting a polyester diol and isophorone diisocyanate. Got.
［実施例１］
（１）緩衝層形成用組成物の調製
　エネルギー線重合性化合物として合計１００質量部（固形分比）となるように、製造例１で合成したウレタンアクリレート系オリゴマー（ＵＡ－１）４０質量部、イソボルニルアクリレート（ＩＢＸＡ）４０質量部、フェニルヒドロキシプロピルアクリレート（ＨＰＰＡ）２０質量部を配合し、さらに光重合開始剤として、１－ヒドロキシシクロヘキシルフェニルケトン（ＢＡＳＦ社製、製品名「イルガキュア１８４」）を２．０質量部、フタロシアニン系顔料を０．２質量部配合し、緩衝層形成用組成物を調製した。 [Example 1]
(1) Preparation of composition for forming buffer layer 40 parts by mass of the urethane acrylate oligomer (UA-1) synthesized in Production Example 1 so that the total amount of the energy ray polymerizable compound is 100 parts by mass (solid content ratio). 40 parts by mass of isobornyl acrylate (IBXA) and 20 parts by mass of phenylhydroxypropyl acrylate (HPPA) were blended, and 1-hydroxycyclohexyl phenyl ketone (product name “Irgacure 184” manufactured by BASF) was used as a photopolymerization initiator. 2.0 parts by mass and 0.2 parts by mass of a phthalocyanine pigment were blended to prepare a composition for forming a buffer layer.
（２）支持体の作製　
　厚さ５０μｍのポリエチレンテレフタレートフィルム（商品名；コスモシャイン、品番；Ａ－４１００、東洋紡（株）製）からなる基材に、硬化後の厚さが２０μｍとなるように上記の緩衝層形成用組成物を塗布し塗布膜を形成した。そして、当該塗布膜に対して、紫外線を照射して、当該塗布膜を半硬化させて、緩衝層形成膜を形成した。
　なお、上記の紫外線照射は、ベルトコンベア式紫外線照射装置（製品名「ＥＣＳ－４０１ＧＸ」、アイグラフィクス社製）及び高圧水銀ランプ（Ｈ０４－Ｌ４１アイグラフィクス社製：Ｈ０４－Ｌ４１）を使用し、ランプ高さ１５０ｍｍ、ランプ出力３ｋＷ（換算出力１２０ｍＷ／ｃｍ）、光線波長３６５ｎｍの照度１２０ｍＷ／ｃｍ２、照射量１００ｍＪ／ｃｍ２の照射条件下にて行った。
　そして、形成した緩衝層形成膜の表面と、剥離シート（（株）リンテック製、商品名「ＳＰ－ＰＥＴ３８１０３１」、シリコーン剥離処理を行ったポリエチレンテレフタレート（ＰＥＴ）フィルム、厚さ：３８μｍ）の剥離処理がされた面とを貼り合わせ、緩衝層形成膜上の剥離シート側から再度紫外線を照射して、当該緩衝層形成膜を完全に硬化させ、厚さ２０μｍの緩衝層を形成した。
　なお、上記の紫外線照射は、上述の紫外線照射装置及び高圧水銀ランプを使用し、ランプ高さ１５０ｍｍ、ランプ出力３ｋＷ（換算出力１２０ｍＷ／ｃｍ）、光線波長３６５ｎｍの照度１６０ｍＷ／ｃｍ２、照射量５００ｍＪ／ｃｍ２の照射条件下にて行った。 (2) Production of support
The above-mentioned composition for forming a buffer layer on a substrate made of a polyethylene terephthalate film (trade name; Cosmo Shine, product number: A-4100, manufactured by Toyobo Co., Ltd.) having a thickness of 50 μm so that the thickness after curing is 20 μm. The product was applied to form a coating film. And the ultraviolet-ray was irradiated with respect to the said coating film, the said coating film was semi-hardened, and the buffer layer formation film was formed.
The above ultraviolet irradiation uses a belt conveyor type ultraviolet irradiation device (product name “ECS-401GX”, manufactured by I-Graphics) and a high-pressure mercury lamp (H04-L41 manufactured by I-Graphics: H04-L41). The measurement was performed under irradiation conditions of a height of 150 mm, a lamp output of 3 kW (converted output of 120 mW / cm), an illuminance of 120 mW / cm 2 with a light wavelength of 365 nm, and an irradiation amount of 100 mJ / cm 2 .
Then, the surface of the formed buffer layer forming film and a release sheet (trade name “SP-PET 381031” manufactured by Lintec Co., Ltd., polyethylene terephthalate (PET) film subjected to silicone release treatment, thickness: 38 μm) are released. The peeled surface was bonded, and ultraviolet rays were irradiated again from the release sheet side on the buffer layer forming film to completely cure the buffer layer forming film, thereby forming a buffer layer having a thickness of 20 μm.
In addition, said ultraviolet irradiation uses the above-mentioned ultraviolet irradiation apparatus and a high pressure mercury lamp, lamp | ramp height 150mm, lamp output 3kW (converted output 120mW / cm), illuminance 160mW / cm < 2 > of light wavelength 365nm, irradiation amount 500mJ / Cm 2 was performed under irradiation conditions.
（３）粘着剤層の形成
　ｎ－ブチルアクリレート６９．５質量部と、メチルアクリレート３０質量部と、２－ヒドロキシエチルアクリレート０．５質量部とを酢酸エチル溶媒中で重合し、重量平均分子量４６万のアクリル系共重合体を得た。この酢酸エチル溶媒で希釈されたアクリル系共重合体１００質量部（固形分換算）と、重量平均分子量２３００のペンタエリスリトール系５～９官能ウレタンアクリレート系オリゴマー１２０質量部と、光重合開始剤としてのイルガキュア１８４（ＢＡＳＦ社製）２．０質量部と、架橋剤としての有機多価イソシアネート化合物（製品名「ＢＨＳ８５１５」、トーヨーケム（株）製）８質量部とを混合してエネルギー線硬化型粘着剤組成物（Ｙ型）の酢酸エチル希釈液を得た。この希釈液を、前記支持体の基材側の面に、乾燥後の厚さが２０μｍとなるように塗布して、その後、１００℃で１分間加熱乾燥して、基材の上に粘着剤層を形成して、表面保護フィルムを得た。 (3) Formation of pressure-sensitive adhesive layer 69.5 parts by mass of n-butyl acrylate, 30 parts by mass of methyl acrylate, and 0.5 parts by mass of 2-hydroxyethyl acrylate were polymerized in an ethyl acetate solvent to obtain a weight average molecular weight of 46 Ten thousand acrylic copolymers were obtained. 100 parts by mass (converted to solid content) of an acrylic copolymer diluted with an ethyl acetate solvent, 120 parts by mass of a pentaerythritol 5-9 functional urethane acrylate oligomer having a weight average molecular weight of 2300, and a photopolymerization initiator Energy ray curable pressure-sensitive adhesive by mixing 2.0 parts by mass of Irgacure 184 (manufactured by BASF) and 8 parts by mass of an organic polyvalent isocyanate compound (product name “BHS8515”, manufactured by Toyochem Co., Ltd.) as a crosslinking agent A diluted ethyl acetate solution of the composition (Y type) was obtained. This diluted solution was applied to the substrate side surface of the support so that the thickness after drying was 20 μm, and then dried by heating at 100 ° C. for 1 minute to form an adhesive on the substrate. A layer was formed to obtain a surface protective film.
［実施例２］
　緩衝層の厚さを５０μｍとした以外は、実施例１と同様にして表面保護フィルムを作製した。 [Example 2]
A surface protective film was produced in the same manner as in Example 1 except that the thickness of the buffer layer was 50 μm.
［実施例３］
　実施例１と同様の基材に厚さ２５μｍの低密度ポリエチレンフィルム（緩衝層）をエポキシ樹脂系接着剤にて貼り合せた厚さ７５μｍの支持体を用いたこと以外は、実施例１と同様にして表面保護フィルムを作製した。 [Example 3]
Similar to Example 1 except that a support having a thickness of 75 μm and a low-density polyethylene film (buffer layer) having a thickness of 25 μm bonded to the same base material as in Example 1 with an epoxy resin adhesive was used. Thus, a surface protective film was produced.
［実施例４］
　実施例１と同様の基材の両面に、厚さ２５μｍの低密度ポリエチレンフィルム（緩衝層及び樹脂層）をエポキシ樹脂系接着剤にて貼り合せた厚さ１００μｍの支持体を作製した。当該樹脂層面上に、実施例１と同様に厚さ２０μｍの粘着剤層を形成して、表面保護フィルムを作製した。 [Example 4]
A support having a thickness of 100 μm was prepared by laminating a low-density polyethylene film (buffer layer and resin layer) having a thickness of 25 μm with an epoxy resin adhesive on both surfaces of the same substrate as in Example 1. A pressure-sensitive adhesive layer having a thickness of 20 μm was formed on the resin layer surface in the same manner as in Example 1 to produce a surface protective film.
［実施例５］
　基材に厚さ１００μｍのポリエチレンテレフタレートフィルム（商品名；コスモシャイン、品番；Ａ－４１００、東洋紡（株）製）を用いた以外は、実施例１と同様にして表面保護フィルムを作製した。 [Example 5]
A surface protective film was produced in the same manner as in Example 1 except that a polyethylene terephthalate film (trade name: Cosmo Shine, product number: A-4100, manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm was used as the substrate.
［比較例１］
　緩衝層を形成しなかったこと以外は、実施例１と同様にして表面保護フィルムを作製した。 [Comparative Example 1]
A surface protective film was produced in the same manner as in Example 1 except that the buffer layer was not formed.
［比較例２］
　基材に厚さ８０μｍの低密度ポリエチレンフィルムを用いた以外は、実施例１と同様にして表面保護フィルムを作製した。 [Comparative Example 2]
A surface protective film was produced in the same manner as in Example 1 except that a low-density polyethylene film having a thickness of 80 μm was used as the substrate.
［比較例３］
　基材に厚さ５０μｍの低密度ポリエチレンフィルムを用いて、緩衝層の厚さを５０μｍとした以外は、実施例１と同様にして表面保護フィルムを作製した。 [Comparative Example 3]
A surface protective film was produced in the same manner as in Example 1 except that a low-density polyethylene film having a thickness of 50 μm was used as the substrate and the thickness of the buffer layer was changed to 50 μm.
［比較例４］
　基材に厚さ１２５μｍのポリエチレンテレフタレートフィルム（商品名；コスモシャイン、品番；Ａ－４１００、東洋紡（株）製）を用いた以外は、実施例１と同様にして表面保護フィルムを作製した。 [Comparative Example 4]
A surface protective film was produced in the same manner as in Example 1, except that a polyethylene terephthalate film (trade name: Cosmo Shine, product number: A-4100, manufactured by Toyobo Co., Ltd.) having a thickness of 125 μm was used as the substrate.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１より、実施例１～５で作製した表面保護フィルムは、加工性及び作業性が共に優れていることが分かる。
　一方、比較例１で作製した表面保護フィルムは、支持体の剛軟度は良好であるため、作業性は優れるものの、緩衝層を有さず、基材への押し込み深さが浅く、加工性に劣る結果となった。
　比較例２及び３では、支持体の剛軟度が低いために作業性が劣る結果となり、また、比較例４では、支持体の剛軟度が高すぎるために作業性が劣る結果となった。 From Table 1, it can be seen that the surface protective films prepared in Examples 1 to 5 are both excellent in workability and workability.
On the other hand, the surface protective film produced in Comparative Example 1 has excellent workability because the support has good bending resistance, but has no buffer layer, has a shallow depth of pushing into the base material, and has good workability. It became inferior result.
In Comparative Examples 2 and 3, the workability was inferior due to the low bending resistance of the support, and in Comparative Example 4, the workability was inferior because the bending resistance of the support was too high. .
　本発明の表面保護フィルムは、加工性及び作業性に優れている。
　そのため、本発明の表面保護フィルムは、例えば、光学部材又は電子部材の表面を保護する表面保護フィルムとして好適に用いることができ、当該用途に使用した際には、フィルム加工性の向上、部材への貼付性向上による貼り直し頻度の低減、及び剥離時の被着体へのダメージを効果的に防止し得る。 The surface protective film of the present invention is excellent in workability and workability.
Therefore, the surface protective film of the present invention can be suitably used as, for example, a surface protective film that protects the surface of an optical member or an electronic member. It is possible to effectively prevent a reduction in the frequency of reattachment due to the improvement of the sticking property and damage to the adherend during peeling.

Claims (12)

  1. 　光学部材又は電子部材に貼付し、その表面を保護するために使用される表面保護フィルムであって、
    　剛軟度が５０００ｍＮ・ｃｍ以上、４５０００ｍＮ・ｃｍ以下である支持体と、該支持体の一方の面に粘着剤層とを備え、
    　該支持体が、エネルギー線重合性化合物を含む緩衝層形成用組成物及び緩衝層形成用樹脂フィルムから選ばれる１種以上からなる緩衝層を有し、先端曲率半径１００ｎｍ及び稜間角１１５°の三角錘形状圧子の先端を１０μｍ／分の速度で、該緩衝層に押し込んだ際の圧縮荷重が２ｍＮに到達するのに必要な押し込み深さ（Ｚ）が２．５μｍ以上である、表面保護フィルム。     A surface protective film that is applied to an optical member or an electronic member and used to protect the surface thereof,
    Comprising a support having a bending resistance of 5000 mN · cm or more and 45000 mN · cm or less, and an adhesive layer on one surface of the support,
    The support has a buffer layer composed of at least one selected from a buffer layer-forming composition containing an energy beam polymerizable compound and a buffer layer-forming resin film, and has a tip curvature radius of 100 nm and a ridge angle of 115 °. Surface protective film having a pressing depth (Z) of 2.5 μm or more required to reach a compression load of 2 mN when the tip of the triangular pyramid-shaped indenter is pressed into the buffer layer at a speed of 10 μm / min. .
  2. 　前記支持体が、さらに基材を有する、請求項１に記載の表面保護フィルム。 The surface protective film according to claim 1, wherein the support further has a base material.
  3. 　前記支持体が、前記基材の緩衝層が設けられる面と反対側の面に更に樹脂層を有する支持体である、請求項２に記載の表面保護フィルム。 The surface protective film according to claim 2, wherein the support is a support further having a resin layer on a surface opposite to a surface on which the buffer layer of the substrate is provided.
  4. 　前記緩衝層が、前記粘着剤層と反対側の面に表出している、請求項１～３のいずれか１項に記載の表面保護フィルム。 The surface protective film according to any one of claims 1 to 3, wherein the buffer layer is exposed on a surface opposite to the pressure-sensitive adhesive layer.
  5. 　前記基材が、ポリエチレンテレフタレートからなる樹脂フィルムである、請求項２～４のいずれか１項に記載の表面保護フィルム。 5. The surface protective film according to claim 2, wherein the substrate is a resin film made of polyethylene terephthalate.
  6. 　前記緩衝層形成用組成物が、前記エネルギー線重合性化合物として、ウレタン（メタ）アクリレート（ａ１）、環形成原子数６～２０の脂環基又は複素環基を有する重合性化合物（ａ２）、及び官能基を有する重合性化合物（ａ３）を含む、請求項１～５のいずれか１項に記載の表面保護フィルム。 The composition for forming a buffer layer is, as the energy ray polymerizable compound, urethane (meth) acrylate (a1), a polymerizable compound (a2) having an alicyclic group or heterocyclic group having 6 to 20 ring-forming atoms, The surface protective film according to any one of claims 1 to 5, comprising a polymerizable compound (a3) having a functional group.
  7. 　前記緩衝層形成用樹脂フィルムが、ポリエチレンフィルムである、請求項１～６のいずれか１項に記載の表面保護フィルム。 The surface protective film according to any one of claims 1 to 6, wherein the resin film for forming a buffer layer is a polyethylene film.
  8. 　前記緩衝層の厚さが５～１００μｍである、請求項１～７のいずれか１項に記載の表面保護フィルム。 The surface protective film according to any one of claims 1 to 7, wherein the buffer layer has a thickness of 5 to 100 µm.
  9. 　前記粘着剤層が、エネルギー線硬化型粘着剤組成物からなる、請求項１～８のいずれか１項に記載の表面保護フィルム。 The surface protective film according to any one of claims 1 to 8, wherein the pressure-sensitive adhesive layer comprises an energy ray-curable pressure-sensitive adhesive composition.
  10. 　前記粘着剤層が、アクリル系共重合体を含むエネルギー線硬化型粘着剤組成物からなり、
    　該アクリル系共重合体が、少なくともアルキル基の炭素数が１又は２であるアルキル（メタ）アクリレートを５～５０質量％含むとともに、カルボキシル基含有モノマーを含まず又は５質量％未満含むモノマー成分を共重合体したものである、請求項１～９のいずれか１項に記載の表面保護フィルム。     The pressure-sensitive adhesive layer is made of an energy ray-curable pressure-sensitive adhesive composition containing an acrylic copolymer,
    The acrylic copolymer contains a monomer component containing at least 5 to 50% by mass of an alkyl (meth) acrylate having an alkyl group having 1 or 2 carbon atoms and not containing a carboxyl group-containing monomer or less than 5% by mass. The surface protective film according to any one of claims 1 to 9, which is a copolymer.
  11. 　光学部材又は電子部材と、該光学部材又は該電子部材の表面に貼付される請求項１～１０のいずれか１項に記載の表面保護フィルムとを備える表面保護フィルム付き部材。 A member with a surface protective film comprising: an optical member or an electronic member; and the surface protective film according to any one of claims 1 to 10 attached to a surface of the optical member or the electronic member.
  12. 　請求項１～１０のいずれか１項に記載の表面保護フィルムを、光学部材又は電子部材の表面に貼付して該表面を保護する方法。 A method for protecting a surface of the optical member or electronic member by applying the surface protective film according to any one of claims 1 to 10 to the surface of the optical member or electronic member.
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