EP3775078A1

EP3775078A1 - Optical laminate, adhesive composition and protective material

Info

Publication number: EP3775078A1
Application number: EP18911991.0A
Authority: EP
Inventors: Tomohiro Miyazaki; Syuji Okamoto; Ruediger Sauer; Wilfried Loevenich; Tetsuya Suzuki
Original assignee: Heraeus Deutschland GmbH and Co KG; Soken Kagaku KK; Soken Chemical and Engineering Co Ltd; Heraeus KK
Current assignee: HERAEUS EPURIO GMBH; Soken Chemical and Engineering Co Ltd; Heraeus KK
Priority date: 2018-03-30
Filing date: 2018-03-30
Publication date: 2021-02-17
Also published as: KR20200138777A; JP2021517607A; TW201942297A; TWI800632B; CN111971356A; WO2019187140A1; CN111971356B; EP3775078A4; KR102446530B1; JP7134326B2

Abstract

An object of the present invention is to provide an optical laminate provided with a protective material that has high antistatic property when peeled from an optical member and has high transmittance, an adhesive composition and a protective material used for these. An optical laminate provided with an optical member, and a protective material laminated on the optical member, in which the protective material has a substrate, and an adhesive layer provided on the substrate, and the adhesive layer contains a (meth)acrylic adhesive polymer having a glass transition temperature of 0°C or lower, a conductive polymer containing a conjugated polymer and a polyanion, and an amphiphilic compound, and is provided so as to adjacent to a surface of the optical member.

Description

OPTICAL LAMINATE, ADHESIVE COMPOSITION AND PROTECTIVE MATERIAL

The present invention relates to an optical laminate, an adhesive composition and a protective material, in particular, relates to an optical laminate having high antistatic property when the protective material is peeled, and an adhesive composition and a protective material used for these.

An adhesive agent having antistatic properties is used as an adhesive layer of a surface protect film, and, for example, is used to prevent flaws or contaminations from adhering on a surface during processing or transporting an optical component or an electronic component such as a Flat Panel Display (FPD). When an adhesive agent having antistatic properties like this is used in a surface protect film, adherence of extraneous materials such as dust or dirt to a target object to which the surface protect film was adhered, due to electrification of static electricity generated during peeling, or electric inconvenience to the electronic components or the like due to electrostatic discharging may be prevented.

In particular, when a conductive polymer having high light transmittance and electric conductivity is used as an antistatic agent, antistatic property having higher function may be expected.

However, since a conductive polymer that is widely used in the present time is a water-dispersive type, it was difficult to add them directly to an adhesive agent of a nonaqueous solvent system.

There, as a conductive polymer stably dispersed even in a nonpolar solvent, an adhesive composition that uses a conductive polymer in which a monoanion is doped is known (Patent Document 1). However, even when the conductive polymer like this was used, it was demanded to lower surface resistivity to further enhance antistatic performance or to more enhance light transmittance of the adhesive layer.

[PTL 1] Japanese Unexamined Patent Application, Publication No. 2008-308539

The present invention intends to provide an optical laminate provided with a protective material having high antistatic property when peeled from an optical member and having high light transmittance, and an adhesive composition and a protective material used for these.

Means for Solving the Problems

In order to solve the above problems, after extensive studies, the present inventors found that when a specific adhesive polymer, a conductive polymer and an amphiphilic compound are contained, the above object can be achieved.

(1) A first invention of the present invention is an optical laminate provided with an optical member, and a protective material laminated on the optical member, in which the protective material has a substrate, and an adhesive layer provided on the substrate, and the adhesive layer contains a (meth)acrylic adhesive polymer having a glass transition temperature of 0°C or lower, a conductive polymer containing a conjugated polymer and a polyanion, and an amphiphilic compound, and is provided so as to adjacent a surface of the optical member.

(2) A second invention of the present invention is the optical laminate of the first invention, in which the amphiphilic compound contained in the adhesive layer is an ether or ester of trivalent or more polyvalent alcohol, or a nonionic compound having an oxyalkylene chain.

(3) A third invention of the present invention is the optical laminate according to any one of the first to the second invention, in which the polyanion contained in the adhesive layer has a hydrogenated or unhydrogenated diene structure.

(4) A fourth invention of the present invention is the optical laminate according to any one of the first to the third invention, in which the polyanion contained in the adhesive layer has a block structure.

(5) A fifth invention of the present invention is the optical laminate according to any one of the first to the fourth invention, in which a rate of (meth)acrylic acid ester units having alkyl groups having 4 or more carbon atoms is 50% by mass or larger among repeating units constituting the adhesive polymer of the adhesive layer.

(6) A sixth invention of the present invention is the optical laminate according to any one of the first to the fifth invention, in which a content of the conductive polymer in the adhesive layer is 0.01 to 20 parts by mass relative to 100 parts by mass of the conductive polymer.

(7) A seventh invention of the present invention is the optical laminate according to any one of the first to the sixth invention, in which a content of the amphiphilic compound in the adhesive layer is 0.1 to 10 parts by mass relative to 100 parts by mass of the adhesive polymer.

(8)An eighth invention of the present invention is the optical laminate according to any one of the first to the seventh invention, in which the optical member is a polarizing plate, a retardation plate, an antireflective film or a transparent conductive film.

(9) A ninth invention of the present invention is an adhesive composition including:
(A) an adhesive polymer that is formed by repeating a (meth)acrylic unit structure and has a glass transition temperature of 0°C or lower;
(B) a conductive polymer containing a conjugated polymer and polyanion;
(C) an amphiphilic compound; and
(D) a nonaqueous solvent or dispersion medium.

(10) A tenth invention of the present invention is the adhesive composition according to the ninth invention, in which the (D) solvent or dispersion medium is one or more kinds selected from ethyl acetate, butyl acetate, toluene, methyl ethyl ketone and anisole.

(11) An eleventh invention of the present invention is the adhesive composition according to the ninth or tenth invention, in which the amphiphilic composition is an ether or an ester of trivalent or more polyvalent alcohol, or a nonionic compound having an oxyalkylene chain.

(12) A twelfth invention of the present invention is the adhesive composition according to any one of the ninth to eleventh invention, in which the polyanion has a hydrogenated or unhydrogenated diene structure.

(13) A thirteenth invention of the present invention is the adhesive composition according to any one of the ninth to twelfth invention, in which the polyanion has a block structure.

(14) A fourteenth invention of the present invention is the adhesive composition according to any one of the ninth to thirteenth invention, in which a rate of (meth)acrylic acid alkyl ester units having an alkyl group having 4 or more carbon atoms is 50% by mass or higher among repeating units constituting the adhesive polymer.

(15) A fifteenth invention of the present invention is the adhesive composition according to any one of the ninth to fourteenth invention, in which a content of the conductive polymer is from 0.01 to 20 parts by mass relative to 100 parts by mass of the adhesive polymer.

(16) A sixteenth invention of the present invention is the adhesive composition according to any one of the ninth to fifteenth invention, in which a content of the amphiphilic compound is from 0.1 to 10 parts by mass relative to 100 parts by mass of the adhesive polymer.

(17) A seventeenth invention of the present invention is the protective material that includes a substrate and an adhesive layer provided on the substrate, in which the adhesive layer includes a (meth)acrylic adhesive polymer having the glass transition temperature of 0°C or lower, a conductive polymer containing a conjugated polymer and polyanion, and an amphiphilic compound.

(18) An eighteenth invention of the present invention is the protective material according to the seventeenth invention, in which the amphiphilic compound contained in the adhesive layer is an ether or ester of a trivalent or more polyvalent alcohol or a nonionic compound having an oxyalkylene chain.

(19) A nineteenth invention of the present invention is the protective material according to the seventeenth or eighteenth invention, in which the haze of the adhesive layer is smaller than 5.

(20) A twentieth invention of the present invention is the protective material according to any one of the seventeenth to nineteenth invention, in which polyanion contained in the adhesive layer has a hydrogenated or unhydrogenated diene structure.

(21) A twenty first invention of the present invention is the protective material according to any one of the seventeenth or twentieth invention, in which the polyanion contained the adhesive layer has a block structure.

(22) A twenty second invention of the present invention is the protective material according to any one of the seventeenth to twenty first invention, in which a rate of (meth)acrylic acid alkyl ester units having an alkyl group having 4 or more carbon atoms is 50% by mass or higher among repeating units constituting the adhesive polymer of the adhesive layer.

(23) A twenty third invention of the present invention is the protective material according to any one of the seventeenth to twenty second invention, in which a content of the conductive polymer in the adhesive layer is from 0.01 to 20 parts by mass relative to 100 parts by mass of the adhesive polymer.

(24) A twenty fourth invention of the present invention is the protective material according to any one of the seventeenth to twenty third invention, in which a content of the amphiphilic compound in the adhesive layer is from 0.1 to 10 parts by mass relative to 100 parts by mass of the adhesive polymer.

Effects of the Invention

According to the present invention, an optical laminate provided with a protective material having high antistatic property when peeled from an optical member and having high light transmittance, and an adhesive composition and a protective material used for these are obtained.

Furthermore, according to the present invention, an optical laminate provided with a protective material having a uniform adhesive layer in which coagulation of a polymer or the like is reduced, an adhesive composition and a protective material used for these are also obtained.

Moreover, according to the present invention, an optical laminate in which an influence to the antistatic property due to a kind of the substrate is reduced when a specific amphiphilic compound is used, an adhesive composition and a protective material are also obtained.

Thus, since the optical laminate, the adhesive composition and the protective material of the present invention have high-function antistatic characteristics, adhesion of extraneous materials due to electrification of static electricity generated and electrical inconveniences to electronic components due to static discharge during peeling the protective material may be reduced.

In the followings, embodiments of the present invention will be described. However, these are shown only illustratively and it goes without saying that various modifications can be applied as long as these do not deviate from a technical idea of the present invention.

<<Optical Laminate>>
An optical laminate of the present invention is provided with an optical member and a protective material laminated on the optical member. Here, the protective material provided on a surface of the optical member is provided with a substrate and an adhesive layer, and the adhesive layer is laminated on the substrate. At this time, in the optical laminate of the present invention, the respective layers are laminated such that one side of the adhesive layer is adjacent to the substrate, and the other side is adjacent to the optical member.

<Optical Member>
Among these, although it is not particularly limited as the optical member, members having the form of a plate, a sheet, a film or the like that are used in optical application are cited, and examples thereof include a polarizing plate, a retardation film, an elliptical polarizing plate, an anti-reflection film, a transparent conductive film, a luminance improving film, a light diffusion film, a glass scattering prevention film and a surface protective film. Among these, the polarizing plate, the retardation film, the anti-reflection film, or the transparent conductive film is preferable, which are frequently adhered to a surface of a liquid crystal element.

<Protective Material>
On the other hand, the protective material is provided with a substrate and an adhesive layer provided on the substrate thereof, and is detachably provided on a surface of the optical member. When an adhesive layer of the protective material is located adjacent to a surface of the optical member, since the adhesive layer is adhered to the surface of the optical member and the surface of the optical member is protected thereby, the protective layer may be preferably used in an application (for a protective film or the like) to protect the surface of an optical member from scratch or contamination.

(Substrate)
The substrate used in the protective material is selected from materials in the form of a thin plate, a sheet or a film or the like to which the adhesive layer may be adhered. For example, plastic materials, metals and metal oxides may be used. Here, when used in applications where light is transmitted via the protective material, substrates having high light transmittance, for example, substrates made of plastic materials, ITO (indium tin oxide), or glass having high light transmittance are preferably used.

Among these, from the viewpoint of using, in particular, in applications of a surface protective film of optical components and electronic components such as FPDs, plastic films having flexibility, plasticity and high light transmittance are preferably used. Examples of the plastic films like this include films made of polymers such as Oriented PolyPropylene (OPP), polycarbonate, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), or polymers such as polymethylmethacrylates (PMMA), polycarbonates, polysulfones, polyether sulfones (PES), polyimides, polyamides, polyethylenes, polypropylenes or cyclic polyolefin or cyclic olefin copolymers (COC), polyvinyl chloride, polystyrene, hydrogenated styrene polymers, or hydrogenated styrene copolymers. In particular, from the viewpoint that the content of the conductive polymer makes it easier to form a conductive path in the inside of the adhesive layer, OPP or PET is more preferably used, and the PET is most preferably used.

A thickness of the substrate is appropriately set in accordance with its application. For example, from the viewpoint of application to the surface protective film, a film thickness is set to preferably 5μm or thicker, more preferably 10 μm or thicker, and more preferably 25 μm or thicker. The upper limit of the thickness of the substrate at this time may be set to preferably 5000 μm or thinner, more preferably 2500 μm or thinner, and still more preferably 1000 μm or thinner.

Here, a surface of the substrate may be pre-treated prior to forming the adhesive layer, for example by corona treatment, primer treatment, flame treatment, fluorination or plasma treatment, to improve the polarity of the surface, more specifically, the wettability and chemical affinity to the adhesive composition. In particular, the surface of the substrate is preferably treated with a primer.

(Adhesive Layer)
An adhesive layer provided on the substrate is formed of an adhesive composition described below, and has low surface resistivity and high antistatic property. According to the adhesive layer like this, generation of the static electricity is reduced when the protective material is peeled off the optical member. Therefore, contamination of a surface of the optical member due to adhesion of extraneous materials such as dusts or dirt generated when a surface of the optical member to which the protective material is adhered is electrified may be reduced.

Here, the antistatic property when the protective material is peeled may be evaluated by, for example, peeling electrification voltage or surface resistivity. The peeling electrification voltage in the protective material of the present invention is preferably 1.00 kV or smaller, more preferably 0.70 kV or smaller, still more preferably 0.50 kV or smaller, and particularly preferably 0.25 kV or smaller when the protective material is adhered to an adherend made of triacetyl cellulose, followed by peeling at a speed of 30 m/min.

Furthermore, for example, when an adhesive layer is formed and dried such that a dry film thickness is 10 μm, the surface resistivity of the adhesive layer is preferably smaller than 1 × 10¹³Ω/□, more preferably smaller than 1 × 10¹²Ω/□, still more preferably smaller than 1 × 10¹¹Ω/□, and further more preferably smaller than 1 × 10¹⁰Ω/□. By forming the adhesive layer like this, high antistatic properties may be exhibited. Therefore, contamination due to adhesion of extraneous materials such as dust or dirt due to the electrification of static electricity to an adherend of the adhesive layer may be reduced.

Furthermore, it is preferable that the adhesive layer is one that can form an adhesive layer having high total light transmittance and low haze. For example, the total light transmittance in an adhesive layer when the adhesive layer is formed and dried such that a dry film thickness is 10 μm is preferably 60% or higher, more preferably 70% or higher, still more preferably 80% or higher, and furthermore preferably 90% or higher. Furthermore, the haze in the adhesive layer at this time is preferably smaller than 5.0%, more preferably smaller 3.0%, and still more preferably smaller than 1.5%. By forming the adhesive layer having high total light transmittance or small haze like this, the transparency of the adhesive layer may be enhanced, and therefore, also in applications of protecting optical members and electronic components including FPDs, the protective material may be preferably used.

Here, the haze (haze degree) in the adhesive layer is obtained from (Td/Tt) × 100 when the total light transmittance is assumed as Tt and the diffusion transmittance is assumed as Td.

A film thickness of the adhesive layer is set according to the kind of adhesive polymer, and has, for example, a film thickness of 0.1 μm or thicker, more preferably 1 μm or thicker, and still more preferably 5 μm or thicker. On the other hand, this adhesive layer has a film thickness of, for example, 100 μm or thinner, more preferably 50 μm or thinner, and still more preferably 30 μm or thinner.

<<Adhesive Composition>>
An adhesive composition capable of forming an adhesive layer like this contains (A) a (meth)acrylic adhesive polymer, (B) a conductive polymer containing a conjugated polymer and polyanion, and (C) an amphiphilic compound and these are dissolved or dispersed in (D) a nonaqueous solvent or a nonaqueous dispersion medium.

A "solution" in the present specification is a concept including also a dispersion liquid, and indicates a state of being dissolved or dispersed in a solvent or a dispersion medium.

<(A) Adhesive Polymer>
An adhesive polymer used in the adhesive composition of the present invention is a polymer having adhesiveness at least at a use temperature and preferably having adhesiveness at room temperature. The adhesive polymer is formed by repeating a (meth)acryl-based unit structure and may be a copolymer. When the adhesive polymer like this is used, the adhesive physical properties of the adhesive composition may be suitably adjusted. Here, the (meth)acryl in the present specification means acryl or methacryl.

Among these, as the (meth)acryl-based polymers, those which are formed by polymerizing a monomer having a polymerizable unsaturated bond having a (meth)acrylic acid ester as a main component may be used. That is, a repeating unit ((meth)acrylic acid ester component unit) derived from (meth)acrylic acid ester is contained by 50% by mass or more, preferably by 70% by mass or more, and more preferably by 90% by mass or more in terms of monomers. As specific examples of the (meth)acryl-based polymers, copolymers of n-butyl acrylate/2-ethylhexyl acrylate/2-hydroxyethyl acrylate, copolymers of n-butyl acrylate/2-ethylhexyl acrylate/2-hydroxyethyl acrylate/acrylic acid, copolymers of 2-ethylhexyl acrylate/2-hydroxyethyl acrylate, copolymers of 2-ethylhexyl acrylate/2-hydroxyethyl acrylate/acrylic acid, copolymers of 2-methoxyethyl acrylate/2-hydroxyethyl acrylate/acrylic acid, and copolymers of 2-methoxyethyl acrylate/2-hydroxyethyl acrylate/acryl amide are exemplified.

As (meth)acrylic acid esters that derive repeating units of (meth)acryl-based polymers, esters between alcohols having an alkyl group having 1 to 20 carbon atoms and (meth)acrylic acid, esters between alicyclic alcohols having 3 to 14 carbon atoms and (meth)acrylic acid, or esters between aromatic alcohols having 6 to 14 carbon atoms and (meth)acrylic acid may be used.

Here, examples of esters between alcohols having an alkyl group having 1 to 20 carbon atoms and (meth)acrylic acid include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, and dodecyl (meth)acrylate. An alkyl group having 3 or more carbon atoms may have a linear structure or a branched structure.

Among the (meth)acrylic acid esters, it is preferable to use esters between alcohol having an alkyl group having 4 or more carbon atoms and (meth)acrylic acid. Furthermore, among repeating units that constitute the adhesive polymer, a rate of (meth)acrylic acid alkyl ester units having an alkyl group having 4 or more carbon atoms is set preferably to 50% by mass or higher, more preferably to 65% by mass or higher, and further preferably to 80% by mass or higher.

On the other hand, as esters between alicyclic alcohols having 3 to 14 carbon atoms and (meth)acrylic acid, cyclohexyl (meth)acrylate and isobornyl (meth)acrylate are exemplified, and as esters between aromatic alcohols having 6 to 14 carbon atoms and (meth)acrylic acid, (meth)acrylic acid aryl esters such as phenyl (meth)acrylate, benzyl (meth)acrylate and phenoxyethyl (meth)acrylate are exemplified.
(Meth)acrylic acid esters like this may be used alone or in a combination thereof.

Furthermore, the (meth)acryl-based polymer may have repeating units derived from monomers copolymerizable with (meth)acrylic acid esters, other than the above (meth)acrylic acid ester component units. Examples of the monomers like this include alkoxyalkyl (meth)acrylates such as (meth)acrylic acid, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and ethoxypropyl (meth)acrylate; salts such as alkali metal (meth)acrylate; di(meth)acrylic acid esters of (poly)alkylene glycol such as di(meth)acrylic acid ester of ethylene glycol, di(meth)acrylic acid ester of diethylene glycol, di(meth)acrylic acid ester of triethylene glycol, di(meth)acrylic acid ester of polyethylene glycol, di(meth)acrylic acid ester of propylene glycol, di(meth)acrylic acid ester of dipropylene glycol and di(meth)acrylic acid ester of tripropylene glycol; poly(meth)acrylic acid esters such as trimethylol propane tri(meth)acrylic acid ester; hydroxy group-containing vinyl compounds such as (meth)acrylonitrile, vinyl acetate, 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl(meth)acrylate,4-hydroxybutyl (meth)acrylate, monoesters between (meth)acrylic acid and polypropylene glycol or polyethylene glycol, and adducts between lactones and 2-hydroxyethyl (meth)acrylate; unsaturated carboxylic acid such as itaconic acid, crotonic acid, maleic acid and fumaric acid (excluding (meth)acrylic acid); salts of these and (partially) esterified compounds and acid anhydrides of these; amide group-containing vinyl monomers such as (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxyethyl (meth)acrylamide and N-butoxymethyl (meth)acrylamide; and macromonomers having a radical polymerizable vinyl group at a terminal of a monomer to which a vinyl group is polymerized. These monomers may be copolymerized alone or in a combination with (meth)acrylic acid ester.

A weight-average molecular weight of the (meth)acryl-based polymer is preferably 50,000 or larger and 2,000,000 or smaller, and more preferably 100,000 or larger and 1,500,000 or smaller from the viewpoint of providing adhesiveness under room temperature. When the weight-average molecular weight is smaller than 50,000, the heat resistance of the obtained adhesive layer may be drastically degraded, and, when the weight-average molecular weight exceeds 2,000,000, a uniform casting operation may be difficult. Here, the weight-average molecular weight of the adhesive polymers including (meth)acryl-based polymers may be obtained by, for example, gel permeation chromatography (GPC).

Furthermore, the glass transition temperature (Tg) of the (meth)acryl-based polymer is preferably 0°C or lower, more preferably -20°C or lower, still more preferably -40°C or lower, and most preferably -50°C or lower, from the viewpoint of imparting the adhesiveness under room temperature in the same manner. On the other hand, the lower limit of the glass transition temperature (Tg) of the (meth)acryl-based polymer is not particularly limited but may be set to -85°C.

The glass transition temperature (Tg) of the (meth)acryl-based polymer (A) may be calculated from a Fox's equation from the glass transition temperatures (Tg₁ to Tg_m) of homopolymers made of monomer units constituting the polymer and a content ratio thereof (W₁ to W_m), for example.
Fox's equation: 1/Tg = (W₁/Tg₁) + (W₂/Tg₂) + ... + (W_m/Tg_m)
W₁ + W₂ + ... + W_m = 1
As the glass transition temperatures (Tg₁ to Tg_m) of homopolymers made of respective polymers in the Fox's equation, values described in Polymer Handbook Fourth Edition (Wiley-Interscience Company, 2003) may be used, for example.

Further, although there is a case that a hydroxyl group may be contained in the (meth)acryl-based polymer, from the viewpoint of the mixing properties with the conductive polymer in the present invention, a hydroxyl value of the relevant polymer is 150 mgKOH/g or smaller, preferably 75 mgKOH/g or smaller, and more preferably 40 mgKOH/g or smaller. Here, the hydroxyl value of the polymer may be measured according to, for example, a neutral titration method defined by JIS K 0070-1992.

In the adhesive composition of the present invention, the adhesive polymers may be used alone or in a combination of two or more kinds.

Further, the adhesive polymer may be used for preparation of the adhesive composition in a state dissolved or dispersed in (D) a solvent or a dispersion medium described below for making it easy to prepare the adhesive composition.

<(B) Conductive Polymer>
The (B) conductive polymer contained in the adhesive composition of the present invention contains (B1) a conjugated polymer and (B2) a polyanion. More specifically, by oxidatively polymerizing monomers under the presence of the (B2) polyanion to form a conjugated polymer, the (B) conductive polymer may be obtained.

A concentration of the (B) conductive polymer in the adhesive composition of the present invention is preferably 0.01 parts by mass or higher, more preferably 0.05 parts by mass or higher, still more preferably 0.1 parts by mass or higher relative to 100 parts by mass of the (A) adhesive polymer. By setting the concentration of the conductive polymer to 0.01 parts by mass or higher, when an adhesive layer is formed from the adhesive composition, the surface resistivity of the adhesive layer decreases. Therefore, static electricity may be suppressed from occurring when peeling the adhesive layer. On the other hand, the concentration of the (B) conductive polymer is preferably 20.0 parts by mass or lower, more preferably 10.0 parts by mass or lower, still more preferably 5.0 parts by mass or lower relative to 100 parts by mass of the (A) adhesive polymer. By setting the concentration of the conductive polymer to 20.0 parts by mass or lower, the mixing stability of the adhesive composition may be improved and aggregated precipitates in the adhesive composition may be reduced, and, the light transmittance in the adhesive layer may be increased and the haze may be reduced.

((B1) Conjugated Polymer)
As the conjugated polymer contained in the conductive polymer, a π electron conjugated system polymer is preferable, and it is more preferable to contain polythiophene present as an electrically conductive polymer.

Here, the polythiophene preferably includes a repeated unit of a general formula (I)
(in the formula, R₄ and R₅, independently from each other, respectively represent H, an optionally substituted C₁-C₁₈ alkyl radical or an optionally substituted C₁-C₁₈alkoxy radical, and R₄ and R₅together represent an optionally substituted C₁-C₈alkylene radical (in the optionally substituted C₁-C₈alkylene radical, one or more C atoms may be substituted by one or more identical or different heteroatoms selected from O or S, preferably a C₁-C₈dioxyalkylene radical), an optionally substituted C₁-C₈oxythialkylene radical or an optionally substituted C₁-C₈ dithialkylene radical, or an optionally substituted C₁-C₈ alkylidene radical (in the optionally substituted C₁-C₈ alkylidene radical, at least one C atom may be optionally substituted by a heteroatom selected from O and S)).

More preferably, the polythiophene includes repeating units of the general formula (I-a) and/or (I-b).
(in the formulas, A represents an optionally substituted C₁-C₅ alkylene radical, preferably an optionally substituted C₂-C₃alkylene radical, Y represents O or S, R₆represents a linear or branched, optionally substituted C₁-C₁₈ alkyl radical, preferably a linear or branched, optionally substituted C₁-C₁₄ alkyl radical, an optionally substituted C₅-C₁₂ cycloalkyl radical, an optionally substituted C₆-C₁₄ aryl radical, an optionally substituted C₇-C₁₈ aralkyl radical, an optionally substituted C₇-C₁₈ alkaryl radical, an optionally substituted C₁-C₄hydroxyalkyl radical or a hydroxyl radical, and y represents an integer of from 0 to 8, preferably 0, 1 or 2, particularly preferably 0 or 1, in which, when a plurality of radicals R₆ are bonded to A, these may be identical or different).

Here, the general formula (I-a) is to be understood to mean that the substituent R₆ may be bonded y times to the alkylene radical A.

More preferably, the polythiophene including repeating units of the general formula (I) is a polythiophene including repeating units of the general formula (I-aa) and/or of the general formula (I-ab)
(In the formula, R₆ and y have the meaning given above.)

Most preferably, the polythiophene including repeating units of the general formula (I) is a polythiophene including a polythiophene of the general formula (I-aaa) and/or the general formula (I-aba).

In the present specification, the prefix "poly" is understood to mean that a plurality of identical or different repeating units are included in the polythiophene. The polythiophene includes in total n repeating units of the general formula (I), wherein n may be an integer of from 2 to 2000, preferably 2 to 100. The repeating units of the general formula (I) within a polythiophene may be in each case identical with each other or different from each other. Polythiophene including identical repeating units of the general formula (I) is preferred in each case.

Preferably, each conjugated polymer has H at the end groups.

As the conjugated polymer, poly(3,4-ethylenedioxythiophene), poly(3,4-ethyleneoxythiathiophene) or poly(thieno[3,4-b]thiophene), that is, a homopolythiophene having repeating units of the general formula (I-aaa), (I-aba) or (I-b) where Y=S is particularly preferred, and homopolymer (poly(3,4-ethylene-dioxythiophene)) including repeating units of the formula (I-aaa) is most preferred.

Furthermore, the conjugated polymers are cationic, wherein the "cationic" relates only to the charges located on the polythiophene main chain. Depending on the substituent group of the radicals R₄ and R₅, the polythiophene may bear positive and negative charges in the structural unit, and in this case, the positive charges may be located on the polythiophene main chain and the negative charges may be optionally located on the radicals R substituted with sulphonate or carboxylate groups. In this case, the positive charges of the polythiophene main chain may be partially or completely saturated by the optionally present anionic groups on the radicals R. Considered as a whole, the polythiophenes in these cases may be cationic, neutral or even anionic. Nevertheless, in the context of the invention, they are all considered as cationic polythiophenes. This is because the positive charges on the polythiophene main chain are important. The positive charges are not represented in the formulas. This is because these positive charges are mesomerically delocalised. However, the number of positive charges is at least 1 and at most n (here, n is the total number of all repeating units (identical or different) within the polythiophene).

As a thiophene monomer that becomes a base of a conjugated polymer, optionally substituted 3,4-alkylenedioxythiophenes may be used, and, as an example, can be represented by the general formula (II)
(in the formula, A, R₆ and y have the meaning described in connection with formula (I-a), and when a plurality of radicals R are bonded to A, these may be identical or different).

As more preferred thiophene monomers, optionally substituted 3, 4-ethylenedioxythiophenes may be used, most preferably, unsubstituted 3, 4-ethylenedioxythiophene may be used.

((B2) Polyanion)
As the polyanion contained as a dopant in the conductive polymer, one having a structure of a homopolymer, a random polymer, or a block copolymer structure may be used, among these, one having a block copolymer structure is preferred. Furthermore, as the polyanion, one having a plurality of anions in one molecule may be used, for example, at least partially sulfonated polymers such as homopolymers of (meth)acrylic acid ester having styrenesulfonic acid, vinylsulfonic acid or sulfonic acid in a molecule, and these copolymers may be used. Among these, it is preferable to use ones having a hydrogenated or unhydrogenated diene structure, for example, sulfonated synthetic rubbers may be used. The sulfonated synthetic rubber is a block copolymer having a styrene unit that is at least partially sulfonated and a diene unit. By using the polyanion having a block copolymer structure like this, the conductive polymer becomes easily dissolved or dispersed in an organic solvent. Therefore, while maintaining the transparency of the adhesive layer, the surface resistivity of the adhesive layer formed of the adhesive composition may be reduced, and static electricity when peeling the adhesive layer may be suppressed to a low level.

In the present specification, the term "sulphonated" is preferably understood to mean that in the styrene units and/or diene units concerned, preferably in the optionally hydrogenated butadiene or isoprene units, an -SO₃X group is bonded to at least one C atom of these units via a sulphur atom (X is preferably selected from the group consisting of H⁺, NH₄ ⁺, Na⁺, K⁺ and Li⁺.) It is particularly preferable when the -SO₃X groups are almost exclusively bonded to the styrene units and accordingly sulphonated styrene units are present.

Further, in the present specification, the terms "hydrogenated, optionally partially alkyl-substituted styrene-diene block copolymers", or "hydrogenated, styrene-isoprene block copolymers" are understood respectively to refer to block copolymers, in which the double bond of the diene unit has been hydrogenated but the aromatic ring system of the styrene unit is not hydrogenated. Further, the term "styrene-diene block copolymers" is further understood to refer to a polymer which includes at least styrene and diene monomer units, and accordingly the presence of further co-monomers is not excluded.

Furthermore, in the present specification, the term "alkyl-substituted styrene-diene block copolymers" is understood as referring to block copolymers in which the styrene unit is alkyl-substituted, whereby in particular a methyl group, an ethyl group, an isopropyl group or a tert-butyl group is considered as an alkyl substituent.

A "sulphonated styrene unit" in this context is preferably understood to mean the unit (III),
and on the other hand, a "sulphonated butadiene unit" is preferably understood to mean, for example, the unit (IV).

Instead of the acid shown in units (III) and (IV), the sulphonate group may also be bonded in the form of a salt, for example in the form of an ammonium salt or an alkali salt, in particular in the form of an Na⁺, K⁺ or Li⁺ salt.

Preferably, the hydrogenated or unhydrogenated, optionally partially alkyl-substituted styrene-diene copolymers contained as the sulfonated synthetic rubber in the conductive polymer are preferably obtainable by sulphonating a styrene-diene copolymer (this may optionally be hydrogenated).

The hydrogenated or unhydrogenated, optionally partially alkyl-substituted styrene-diene copolymer may in principle be a styrene-diene block copolymer. A "block" in this context is understood to be a polymer unit consisting of at least 2, preferably at least 4, still more preferably at least 6, still more preferably at least 8 and most preferably at least 10 identical monomer units continuous with each other.

Therefore, the hydrogenated or unhydrogenated block copolymers may be copolymers in which only the styrene units are present in blocks, copolymers in which only the diene units (or the hydrogenated forms of the diene units) are present in blocks, or copolymers in which both the diene units (or the hydrogenated forms of the diene units) and the styrene units are present in blocks. For example, hydrogenated or unhydrogenated block copolymers in which styrene blocks are present in addition to monomeric styrene units and diene units (or the hydrogenated forms of the diene units), hydrogenated or unhydrogenated block copolymers in which diene blocks (or blocks of the hydrogenated forms of the diene units) are present in addition to monomeric styrene units and diene units (or the hydrogenated forms of the diene units), hydrogenated or unhydrogenated block copolymers in which styrene blocks and diene blocks (or blocks of the hydrogenated forms of the diene units) are present in addition to monomeric diene units (or the hydrogenated form of the diene units), hydrogenated or unhydrogenated block copolymers in which styrene blocks and diene blocks (or blocks of the hydrogenated forms of the diene units) are present in addition to monomeric styrene units, or hydrogenated or unhydrogenated block copolymers in which styrene blocks and diene blocks (or blocks of the hydrogenated forms of the diene units) are present in addition to monomeric diene units (or the hydrogenated forms of the diene units) and monomeric styrene units are also conceivable.

According to a particular embodiment, the sulphonated synthetic rubber includes hydrogenated or unhydrogenated, preferably hydrogenated styrene-isoprene block copolymers having a structure A-B-A, in which the block A corresponds to a sulphonated polystyrene block and the block B corresponds to a hydrogenated or unhydrogenated, preferably however hydrogenated polyisoprene block (a fully hydrogenated polyisoprene block corresponds chemically to a block of alternating copolymerized ethylene-propylene units). The lengths of the blocks A and B are preferably at least 5 monomer units, particularly preferably at least 10 units and most preferably at least 20 units.

According to another specific embodiment, the sulphonated synthetic rubber includes a hydrogenated or unhydrogenated, preferably, a hydrogenated styrene-isoprene block copolymer having a structure of A-B-C-B-A in which the block A corresponds to a polystyrene block which is at least partially substituted with tert-butyl groups, the block B corresponds to a hydrogenated or unhydrogenated, preferably however hydrogenated polyisoprene block (a fully hydrogenated polyisoprene block corresponds chemically to a block of alternating copolymerized ethylene-propylene units), and the block C corresponds to a sulphonated polystyrene block. The lengths of the blocks A, B and C are preferably at least 5 monomer units, particularly preferably at least 10 units, and most preferably at least 20 units. Such copolymers are obtainable, for example, from the company Kraton Polymers, Houston, USA, under the product name NEXAR^(R).

There are no limits in principle regarding the mass ratio of styrene units to diene units in the hydrogenated or unhydrogenated styrene-diene block copolymer used for sulphonation. For example, the block copolymer may be based on 5 to 95% by mass, particularly preferably 15 to 80% by mass and most preferably 25 to 65% by mass of polymerized styrene and 95 to 5% by mass, preferably 80 to 15% by mass and most preferably 65 to 25% by mass of polymerized, optionally hydrogenated diene, whereby the total amount of optionally hydrogenated diene and styrene is preferably 100% by mass. However, the total amount does not need to be 100% by mass when further monomer units are present in the block copolymer in addition to the styrene units and the optionally hydrogenated diene units.

In conjunction with the sulphonated synthetic rubber, this sulphonated synthetic rubber is furthermore preferable to have a weight-average molecular weight (Mw) in the range of from 1000 to 10,000,000 g/mol, particularly preferably in the range of from 10,000 to 1,000,000 g/mol and most preferably in the range of from 100,000 to 1,000,000 g/mol. The molecular weight is determined by gel permeation chromatography using polymers having definite molecular weights, in particular using polystyrene in the case of water-immiscible solvents or dispersion media, or using polystyrene sulphonic acid in the case of water-miscible solvents or dispersion media.

A mass ratio of the (B1) conjugated polymer to the (B2) polyanion (conjugated polymer : polyanion) in the conductive polymer is preferably in the range of from 1 : 0.1 to 1 : 100, more preferably in the range of from 1 : 0.2 to 1 : 20 and further preferably in the range of from 1 : 0.5 to 1 : 10.

((B3) Oxidant and Reactant Thereof)
An oxidant or its reactant may be contained in the conductive polymer. This is because a polymerization reaction of a thiophene monomer under the presence of the sulfonated synthetic rubber is oxidatively performed by using an oxidant.

As the oxidant, for practical reasons, inexpensive and easy-to-handle oxidants are preferred, for example, iron (III) salts such as Fe₂(SO₄)₃, FeCl₃, Fe(ClO₄)₃ and the iron(III) salts of organic acids and the iron (III) salts of inorganic acids including organic radicals may be used. The iron (III) salts of sulphuric acid hemiesters of C₁-C₂₀ alkanols, for example the Fe (III) salt of lauryl sulphate, are cited by way of example of iron (III) salts of inorganic acids including organic radicals. The followings are cited by way of example of the iron(III) salts of organic acids: the Fe(III) salts of C₁-C₂₀ alkyl sulphonic acids, such as methane sulphonic acid and dodecane sulphonic acid; Fe (III) salts of aliphatic C₁-C₂₀ carboxylic acids such as 2-ethylhexyl carboxylic acid; Fe (III) salts of aliphatic perfluorocarboxylic acids, such as trifluoroacetic acid and perfluorooctanoic acid; Fe (III) salts of aliphatic dicarboxylic acids such as oxalic acid; and, above all, Fe (III) salts of aromatic sulphonic acids optionally substituted with C₁-C₂₀ alkyl groups, such as benzenesulphonic acid, p-toluenesulphonic acid and dodecylbenzenesulphonic acid. The iron (III) salts of organic acids have the big applicational advantage that they are partially or completely soluble in organic solvents and in particular in water-immiscible organic solvents. Further, organic peroxides such as tert-butyl peroxide, benzoyl peroxide, diisobutyryl peroxide, di-n-propyl peroxydicarbonate, didecanoyl peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, di-tert-amyl peroxide may also be used as oxidants. For example, organic azo compounds such as 2,2'-azodiisobutyronitrile and inorganic oxidants such as ammonium persulfate may also be used.

<(C) Amphiphilic Compound>
The adhesive composition in the present invention includes an amphiphilic compound. When the amphiphilic compound like this is contained, lower surface resistivity may be stably provided to the adhesive layer, and, haze of the adhesive layer may be reduced to enhance light transmittance.

As the amphiphilic compound, compounds having high affinity to both aqueous solvents (solvents or dispersion media) and nonaqueous solvents may be used, and nonionic compounds having a hydrophilic group and a hydrophobic group in a molecule are preferable.

As the nonionic amphiphilic compounds, nonionic compounds having an ether or ester of trivalent or more polyvalent alcohol, or an oxyalkylene chain as a hydrophilic group are preferred. Among these, esters of trivalent or more polyvalent alcohols are preferred, and compounds that are aliphatic acid esters of trivalent or more polyvalent alcohols and do not have a polyoxyalkylene structure are more preferred. In particular, by using the ester of trivalent or more polyvalent alcohol, an influence on the surface resistivity and antistatic property due to the kind of the substrate may be reduced.

Among these, ethers and esters of trivalent or more polyvalent alcohols are compounds having three or more in total of hydroxyl groups, ether bonds or ester bonds in a molecule. Furthermore, as the compounds having an oxyalkylene chain, compounds having oxyethylene or oxypropylene as a repeating structural unit may be used, and the number of repeating units in the oxyalkylene chain is preferably 2 or larger and more preferably 5 or larger. In these compounds, the hydrophilicity is exhibited in the hydroxyl group, ether bond and ester bond.

Specific examples of nonionic amphiphilic compounds include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyalkylene derivatives such as polyoxyethylene alkylene alkyl ether; polyoxyethylene alkenyl ether and polyoxyethylene alkyl phenyl ether; sorbitan aliphatic acid esters such as sorbitan octadecanoic acid ester, sorbitan lauric acid ester, sorbitan oleic acid ester, sorbitan stearic acid ester and sorbitan palmitic acid ester; sucrose fatty acid esters such as sucrose oleic acid ester; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monolaurate, and polyoxyethylene sorbitan monooleate; polyoxyethylene sorbitol fatty acid ester; glycerin fatty acid ester; polyoxyethylene fatty acid esters such as polyethylene glycol monolaurate and polyethylene glycol distearate; polyoxyethylene cured castor oil, polyoxyethylene alkyl amine, alkyl alkanol amide; and block copolymers having a unit structure such as polyethylene glycol or polypropylene glycol.

A content of the (C) amphiphilic compound is adjusted to, preferably, for example, 0.1 part by mass or higher, more preferably 0.5 parts by mass or higher, and further preferably 1.0 parts by mass or higher relative to 100 parts by mass of the (A) adhesive polymer. Furthermore, the content of the (C) amphiphilic compound is adjusted to, preferably, for example, 10.0 part by mass or lower, more preferably 8.0 parts by mass or lower, and further preferably 5.0 parts by mass or lower relative to 100 parts by mass of the (A) adhesive polymer.

<(D) Solvent or Dispersion Medium>
The adhesive composition includes a nonaqueous solvent or dispersion medium. More specifically, the adhesive composition contains a solvent or a dispersion medium in which a concentration of water in the solvent or dispersion medium is preferably smaller than 1% by mass, more preferably smaller than 0.5% by mass, still more preferably smaller than 0.1% by mass, and furthermore preferably smaller than 0.01% by mass. By using such nonaqueous solvents or nonaqueous dispersion media, dissolution and dispersion of the adhesive polymer in the adhesive composition may be expedited, and thereby, formation of aggregated precipitates in the adhesive composition may be reduced. Here, the concentration of water may be measured by means of, for example, the Karl Fischer titration method.

As the solvents or dispersion media, linear, branched or cyclic aliphatic hydrocarbons such as pentane, hexane, heptane, octane, petroleum ether, cyclohexane, methyl cyclohexane or cycloheptane; aromatic hydrocarbons such as benzene, toluene or xylene; mono- or bivalent alcohols such as methanol, ethanol, iso-propanol, butanediol, diethylene glycol, or triethylene glycol; ethers such as diethyl ether, diisopropyl ether, methyl tert-butyl ether or anisole; halogenated hydrocarbons such as dichloromethane, chloroform, tetrachloromethane, trichloroethane and trichloroethene; halogenated aromatic hydrocarbons such as chlorobenzene; aliphatic nitriles such as for example acetonitrile; aliphatic sulphoxides and sulphones such as dimethyl sulphoxide or sulpholane; aliphatic carboxylic acid amides such as methyl acetamide, dimethyl acetamide or dimethyl formamide; ketones such as acetone, methyl ethyl ketone or methyl t-butyl ketone; and esters such as methyl acetate, ethyl acetate or butyl acetate; or mixtures of these are cited. Among these, as the solvent or dispersion medium, one or more kinds selected from ethyl acetate, butyl acetate, toluene, methyl ethyl ketone, propylene glycol, and anisole are preferably used.

It is preferable to adjust a content of the (D) solvent or dispersion medium to, for example, 10 parts by mass or higher, more preferably 25 parts by mass or higher, still more preferably 100 parts by mass or higher relative to 100 parts by mass of the (A) adhesive polymer. Furthermore, it is preferable to adjust the content of the (D) solvent or dispersion medium to, for example, 50,000 parts by mass or lower, more preferably to 10,000 parts by mass or lower, and furthermore preferably to 1,000 parts by mass relative to 100 parts by mass of the (A) adhesive polymer.

<Other Components>
In the adhesive composition, an antioxidant, a light stabilizer, a metal corrosion inhibitor, an adhesion imparting agent, a plasticizer, an antistatic agent, a crosslinking accelerator, and a rework agent may be further blended in the range that does not damage an effect of the present invention. Furthermore, various components such as a high conductivity enhancing agent and so on may be contained to improve the electric conductivity of the conductive polymer.

Furthermore, water content in the adhesive composition is preferable to be slight. More specifically, a concentration of water in the adhesive composition is preferably lower than 0.5% by mass, more preferably lower than 0.1% by mass, and still more preferably lower than 0.01% by mass. When water content in the adhesive composition is reduced, formation of aggregated precipitates in the adhesive composition may be reduced, furthermore, the surface resistivity of the adhesive layer may be reduced.

<Formation of Adhesive Layer>
By applying the adhesive composition to a surface of a substrate pre-treated as need arises, a protective material provided with an adhesive layer may be obtained. Here, as the means for applying the adhesive composition, known methods, for example, wire-bar coating, spin coating, dipping (immersing), pouring, dropping on, injecting, spraying, doctor blade coating, coating or printing may be used. Among these, as the means for printing, inkjet printing, screen printing, relief printing, offset printing or pad printing may be used.

A film thickness before drying of the adhesive composition provided to the substrate is set in accordance with a concentration of a non-volatile component in the adhesive composition or a thickness of the adhesive layer after drying. For example, the adhesive composition may be applied to the substrate at a thickness of preferably 0.1 μm or thicker, more preferably 0.5 μm or thicker, and may be applied to the substrate at a thickness of preferably 250 μm or thinner, and more preferably 150 μm or thinner.

Next, by removing at least partially the organic solvent from the adhesive composition applied on the substrate, an adhesive layer may be obtained. The organic solvent may be partially removed by drying at a temperature of from 20°C to 200°C. Here, in particular, when a polymer that is cured by a crosslinking reaction or the like is used as the adhesive polymer, in conjunction with the partial removal of the organic solvent, the polymer may be cured.

In what follows, although the present invention will be described in more detail with reference to Examples, the present invention is by no means limited to these descriptions.

<Preparation of Solution of Adhesive Polymer (A)>
(Experimental Example A-1)
As the adhesive polymer, a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight-average molecular weight: 500,000, glass transition temperature: -68°C, hydroxyl value: 5 mgKOH/g) was prepared according to the following procedure. First, to a flask provided with a stirrer, a nitrogen gas introducing pipe, a thermometer and a reflux cooling pipe, 2-ethylhexyl acrylate (289.5 g), 2-hydroxyethyl acrylate (9.0 g), acrylic acid (1.5 g), ethyl acetate (350.0 g) and toluene (230.0 g) were charged, followed by heating the content of the flask to 66°C while introducing nitrogen gas into the flask. Then, sufficiently nitrogen gas substituted azobisisobutyllonitrile (AIBN)(0.15 g) was added into the flask under stirring. Heating was performed for 3 hours such that the temperature of the content of the flask was maintained at 65 to 66°C. After that, by heating to 75°C and by performing reflux for 5 hours, finally toluene (120 g) was added, and an adhesive polymer solution (A-1) was obtained. The adhesive polymer solution contains an acryl polymer that contains 2-ethylhexyl acrylate/2-hydroxyethyl acrylate/acrylic acid at a monomer weight ratio of 96.5/3/0.5 and a mixed solvent that has a solvent composition of ethyl acetate/toluene at 50/50.

A weight-average molecular weight (Mw) of the obtained adhesive polymer solution was measured according to the following measurement conditions of gel permeation chromatography (GPC). Also, a heating residue (nV) at 105°C was measured under the following condition and it was confirmed that the solid content is 30%. Furthermore, regarding the viscosity of the adhesive polymer solution, initial viscosity at 25°C was measured using a viscometer (B II Type, manufactured by Toki Sangyo Co., Ltd.) and found to be 2.5 Pa・s.

<GPC Measurement Condition>
Measurement Device: HLC-8120GPC (manufactured by TOSOH Corporation)
GPC Column Configuration: The following 5 Consecutive Column Configuration (all manufactured by TOSOH Corporation)
(1)TSK-GEL HXL-H (Guard Column)
(2)TSK-GEL G7000HXL
(3)TSK-GEL GMHXL
(4)TSK-GEL GMHXL
(5)TSK-GEL G2500HXL
Sample concentration: Diluted with tetrahydrofuran so as to be 1.0 mg/cm³
Mobile phase solvent: Tetrahydrofuran
Flow rate: 1 ml/min
Column temperature: 40°C

<Measurement Method of Heating Residue (nV) at 105°C>
Into a precisely measured tin petri dish (n1), about 1 g of an adhesive polymer solution was poured, a total weight (n2) was precisely measured, followed by heating at 105°C for 3 hours. After that, this tin petri dish was left to stand in a desiccator at room temperature for 1 hour, followed by precisely measuring again to measure a total weight (n3) after heating. By using obtained weight measurement values (n1 to n3), the heating residue (nV) was calculated from the following formula. Heating residue (%) = 100 × [weight after heating (n3-n1)/weight before heating (n2-n1)]

(Experimental Example A-2)
As the adhesive polymer, a copolymer of n-butyl acrylate and 2-hydroxyethyl acrylate (weight-average molecular weight: 500,000, glass transition temperature: -48°C, hydroxyl value: 5 mgKOH/g) was prepared according to the following procedure. In the same flask as in Experimental Example A-1, n-butyl acrylate (289.5 g), 2-hydroxyethyl acrylate (9.0 g), acrylic acid (1.5 g) and ethyl acetate (580 g) were charged, followed by heating the content of flask at 66°C while introducing nitrogen gas into the flask. Then, sufficiently nitrogen gas substituted azobisisobutyllonitrile (AIBN) (0.15 g) was added into the flask under stirring. Heating was performed for three hours such that the temperature of the content of the flask was maintained at 65°C to 66°C. After that, by heating to 75°C and by performing reflux for 5 hours, finally ethyl acetate (120 g) was added, and an adhesive polymer solution (A-2) was obtained. The adhesive polymer solution contains an acryl polymer that contains n-butyl acrylate/2-hydroxyethyl acrylate/acrylic acid at a monomer weight ratio of 96.5/3/0.5 and an ethyl acetate as the solvent.

A weight-average molecular weight (Mw) of the obtained adhesive polymer solution was measured according to the above measurement conditions of gel permeation chromatography (GPC), in the same manner as in Experimental Example A-1. Also, a heating residue (nV) at 105°C was measured under the above condition and it was confirmed that the solid content is 30%. Furthermore, regarding the viscosity of the adhesive polymer solution, initial viscosity at 25°C was measured using a viscometer (B II Type, manufactured by Toki Sangyo Co., Ltd.) and found to be 4.1 Pa・s.

<Preparation of Conductive Polymer (B)>
(Experimental Example B-1)
Anisole (283.0 g), benzoyl peroxide (9.4 g), a solution of a sulphonated block polymer that is polyanion (Kraton Nexar MD9260, non-volatile content: 11%) (75.0 g), and p-toluene sulphonic acid (2.8 g) were charged to a three neck flask of 1 liter and mixed, followed by stirring under a nitrogen atmosphere for 30 minutes. After heating to 60°C, 3,4-ethylene dioxythiophene (4.95 g) that is a monomer of a conjugated polymer was added, followed by dropping additional anisole (40.0 g) for 40 minutes. After that, stirring was performed at 60°C for 3 hours. After returning to room temperature, the obtained dispersion liquid was left to stand overnight, an aggregated material was removed by filtering, and a uniform dispersion was obtained. Butyl acetate (20.0 g) was added to the obtained dispersion (20.0 g), followed by ultrasonically dispersing, and a conductive polymer dispersion (B-1) was obtained. At this time, a content of water contained in the dispersion of the conductive polymer was 8 ppm relative to a total mass of the dispersion medium. Furthermore, a content of a nonvolatile component in the dispersion of the conductive polymer was 1.2% by mass and the conductivity of the nonvolatile component was 5.8 S/cm.

(Experimental Example B-2)
In the present Experimental Example, by using an aqueous dispersion of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT/PSS), an operation of substituting the dispersion medium with an organic solvent was performed.

By freeze-drying a PEDOT/PSS dispersion liquid having a non-volatile component of 1.2% (Clevios P T2 manufactured by Heraeus), a dried PEDOS/PSS was obtained.

By mixing the obtained PEDOT/PSS powder (1.2 g) and propylene glycol (35.0 g), an auxiliary dispersion liquid was obtained. Then, t-butyl amine (0.5 g) and methyl ethyl ketone (65.0 g) were added, followed by ultrasonically dispersing, and thus a solvent dispersion liquid of a butyl amine modified product of which solvent dispersion stability of the PEDOT/PSS was improved was prepared, and this was taken as a conductive polymer dispersion liquid (B-2). At this time, a content of water contained in the dispersion liquid of the PEDOT/PSS modified product was 37 ppm relative to the total mass of the dispersion medium.

(Experimental Example B-3)
In the present Experimental Example, a solvent dispersion liquid of PEDOT was prepared without using a polyanion.

3,4-ethylenedioxythiophene (EDOT)(1.42 g) that is a monomer of a conjugated polymer and Di-2-ethylhexyl Sodium Sulfosuccinate (AOT)(3.10 g) were mixed with water (120.0 g), followed by adding ammonium persulfate (3.1 g) that is an oxidant and ferric sulphate (0.08 g) thereto to polymerize the monomer, and thus the PEDOT/AOT was obtained. After the obtained PEDOT/AOT was subjected to a solid -liquid separation, one taken out as a wet product was subjected to freeze-drying to remove water.

The obtained PEDOT/AOT powder (0.12 g) was added to methyl ethyl ketone (MEK) (10.0 g) that is a solvent or a dispersion medium and subjected to ultrasonic dispersion, and thus a dispersion liquid of the PEDOT/AOT was prepared, and this was taken as a conductive polymer dispersion (B-3). At this time, the content of water contained in the PEDOT/AOT dispersion liquid was 12 ppm to a total mass of the dispersion medium.

(Preparation of Amphiphilic Compound (C))
As an amphiphilic compound (C), the following materials were prepared.
Amphiphilic compound (C-1): octyl phenol ethoxylate (manufactured by Dow Chemical, product name: Triton X 100)
Amphiphilic compound (C-2): polyethylene glycol-polypropylene oxyglycol block copolymer (manufactured by Sigma-aldrich, product name: Pluronic^(R) F-68).
Amphiphilic compound (C-3): Sorbitan mono-octadecanoate (manufactured by Croda, product name: Span 60)
Amphiphilic compound (C-4): polyoxyethylene sorbitan monostearate (manufactured by Croda, product name: Tween 60).
Amphiphilic compound (C-5): Sucrose oleic acid ester (manufactured by Mitsubishi Chemical Foods Corporation, product name: Ryoto Sugar Ester O-1570)

<Preparation of Adhesive Composition>
In the followings, contents of the respective components, and characteristics of the adhesive compositions and the adhesive layers in Examples 1 to 10 and Comparative Examples 1 to 4 are shown.

(A) An adhesive polymer, (B) a conductive polymer, (C) an amphiphilic compound and (D) a solvent/dispersion medium of kinds shown in Table 1 were charged into a mixer such that a mass ratio shown in Table 1 is obtained, followed by stirring and mixing, thus an adhesive composition was obtained.

<Characteristics Evaluation of Adhesive Layer>
Furthermore, each of the adhesive compositions of Examples 1 to 10 and Comparative Examples 1 to 4 was laminated on a substrate made of a PET film (manufactured by DuPont, product name: Melinex OD) having a thickness of 175 μm with a primer layer on a surface thereof (hereinafter referred to as “substrate A”) and on a substrate made of a PET film (manufactured by DuPont, product name: Melinex 5066) having a thickness of 175 μm without a primer layer on a surface thereof (hereinafter referred to as “substrate B”) such that each dry film thickness may be 10 μm by a wire-bar coat, followed by drying at a temperature of 90°C for 5 minutes to form an adhesive layer, thus a protective material was obtained. Surface resistivity and haze of the obtained protective material were measured and the presence or absence of aggregated matter was evaluated.

(Measurement of Surface Resistivity)
The surface resistivity was measured according to JIS-K-6911 at an input voltage of 1000 V under atmosphere of a temperature of 23°C and humidity of 50% RH, by using a resistivity meter (Hi-Rester UX MCP-HT800, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). Then, a ratio (β/α) of the surface resistivity (α) of a protective material formed on the substrate A and the surface resistivity (β) of a protective material formed on the substrate B was obtained as a substrate-dependent factor, and, from a magnitude of the numerical value, an influence due to the kind of the substrate on the antistatic property was evaluated.

(Measurement of Haze)
Furthermore, the substrate was peeled from the obtained protective material to take out the adhesive layer, followed by adhering this to a transparent glass to prepare a test piece, using a Haze Meter (HM-150, manufactured by Murakami Color Research Laboratory), the haze of the adhesive layer was measured, followed by evaluating into 4 grades according to the following criteria.
Excellent: Haze is smaller than 1.5
Good: Haze is 1.5 or larger and smaller than 3.0
Poor: Haze is 3.0 or larger and smaller than 5.0
Bad: Haze is 5.0 or larger

(Measurement of Peeling Electrification Voltage)
A laminate was formed by adhering an acryl plate (70 mm × 150 mm × 1 mm) and a polarizing plate made of triacetyl cellulose (AG polarizing plate, plane polarizing plate) such that an AG surface or a plane surface of the polarizing plate is located on an outer side, followed by neutralizing by a static eliminator (SJ-F300, manufactured by KEYENCE Corp.). Adhesive sheets (samples prepared with a PET with primer (substrate A)) obtained in Examples and Comparative Examples were cut into 40 mm × 150 mm, followed by pressure molding with a 2 Kg rubber roller on an AG surface and a plane surface of a laminated body that was neutralized in advance. After leaving for 1 day under a condition of air temperature of 25°C and humidity of 65%, followed by neutralizing again, further followed by measuring a surface potential of the laminate when peeled at a peeling speed of 30 m/min and a peeling angle of 180° by a potential measurement device (SK-200, manufactured by KEYENCE Corp.).

(Results of Characteristics Evaluation)
Regarding the antistatic property of the adhesive layer, as shown in Table 2, in Examples 1 to 10, the surface resistivities of the protective materials formed on the substrate A were smaller than 1×10¹³Ω/□, more specifically smaller than 1×10¹²Ω/□. On the other hand, in Comparative Examples 1, 2 and 4, the surface resistivity of the protective materials formed on the substrate A were 1×10¹³Ω/□ or larger. Furthermore, in Examples 1 to 10, the peeling electrification voltages of the protective materials formed on the substrate A were 1.00 kV or smaller, more specifically 0.23 kV or smaller. On the other hand, in Comparative Examples 1 and 4, the surface resistivities of the protective materials formed on the substrate A were larger than 1.00 kV. From these, it is assumed that by using the amphiphilic compound in the adhesive layer of the protective material, high antistatic properties are provided on the adhesive layer.

In particular, among these examples, in Example 1 where a conductive polymer dispersion (B-1) having a diene structure in a molecule was used, the surface resistivity of the protective material formed on the substrate A was 8×10¹⁰Ω/□. This value was a value lower than 7×10¹¹Ω/□ that is the surface resistivity of Example 3 in which the conductive polymer dispersion (B-2) that does not have a diene structure was used. Furthermore, in Example 1 where the conductive polymer dispersion (B-1) was used, the peeling electrification voltage of the protective material formed on the substrate A was 0.07 kV, and became a value lower than 0.23 kV that is the surface resistivity of Example 3 in which a conductive polymer dispersion (B-2) was used. From these, it is assumed that by using the conductive polymer having a diene structure in a molecule, the antistatic properties of the adhesive layer may be further enhanced.

Furthermore, particularly in Examples 5 to 10, the surface resistivities of the protective materials formed on the substrate B were also lower than 1×10¹⁴Ω/□, more specifically 6×10¹³Ω/□, and the substrate dependent factor became 67 or smaller. On the other hand, in Comparative Examples 1 to 4, the surface resistivities of the protective materials formed on the substrate B were 1×10¹⁴Ω/□ or higher, and the substrate dependent factor exceeded also 100. From these, it is assumed that by using the ester of, in particular, trivalent or more polyvalent alcohol as the amphiphilic compound, influences on the surface resistivity or antistatic property due to the kind of the substrate may be reduced.

On the other hand, regarding the haze of the adhesive layer, as shown in Table 2, values of the haze of the adhesive layers in Examples 1 to 10 were small, and all were evaluated as "excellent", "good" or "poor". On the other hand, in Comparative Examples 3 and 4, the values of the haze of the adhesive layers were high and evaluated as "bad". From these, it is assumed that an effect of enhancing light transmittance by reducing the haze of the adhesive layer is exhibited by making the conductive polymer containing polyanion contain in the adhesive layer, and by making the amphiphilic compound contain in the adhesive layer.

By the way, evaluation results about the presence or absence of aggregated material, and evaluation results of the haze were the same irrespective of the presence or absence of primer coating on the PET substrate.

Claims

　An optical laminate provided with an optical member, and a protective material laminated on the optical member,
　wherein the protective material has a substrate, and an adhesive layer provided on the substrate, and
　the adhesive layer contains a (meth)acrylic adhesive polymer having a glass transition temperature of 0°C or lower, a conductive polymer containing a conjugated polymer and a polyanion, and an amphiphilic compound, and is provided so as to adjacent to a surface of the optical member.
　The optical laminate according to Claim 1, wherein the amphiphilic compound contained in the adhesive layer is an ether or ester of trivalent or more polyvalent alcohol, or a nonionic compound having an oxyalkylene chain.
　The optical laminate according to Claim 1 or 2, wherein the polyanion contained in the adhesive layer has a hydrogenated or unhydrogenated diene structure.
　The optical laminate according to any one of Claims 1 to 3, wherein the polyanion contained in the adhesive layer has a block structure.
　The optical laminate according to any one of Claims 1 to 4, wherein among repeating units constituting the adhesive polymer of the adhesive layer, a rate of (meth)acrylic acid ester units having alkyl groups having 4 or more carbon atoms is 50% by mass or larger.
　The optical laminate according to any one of Claims 1 to 5, wherein a content of the conductive polymer in the adhesive layer is 0.01 to 20 parts by mass relative to 100 parts by mass of the conductive polymer.
　The optical laminate according to any one of Claims 1 to 6, wherein a content of the amphiphilic compound in the adhesive layer is 0.1 to 10 parts by mass relative to 100 parts by mass of the adhesive polymer.
　The optical laminate according to any one of Claims 1 to 7, wherein the optical member is a polarizing plate, a retardation plate, an antireflective film or a transparent conductive film.
　An adhesive composition comprising:
　(A) an adhesive polymer that is formed by repeating a (meth)acryl-based unit structure and has a glass transition temperature of 0°C or lower;
　(B) a conductive polymer containing a conjugated polymer and a polyanion;
　(C) an amphiphilic compound; and
　(D) a nonaqueous solvent or dispersion medium.
　The adhesive composition according to Claim 9, wherein the (D) solvent or dispersion medium is one or more kinds selected from ethyl acetate, butyl acetate, toluene, methyl ethyl ketone and anisole.
　The adhesive composition according to Claim 9 or 10, wherein the amphiphilic composition is an ether or an ester of trivalent or more polyvalent alcohol, or a nonionic compound having an oxyalkylene chain.
　The adhesive composition according to any one of Claims 9 to 11, wherein the polyanion has a hydrogenated or unhydrogenated diene structure.
　The adhesive composition according to any one of Claims 9 to 12, wherein the polyanion has a block structure.
　The adhesive composition according to any one of Claims 9 to 13, wherein a rate of (meth)acrylic acid alkyl ester units having an alkyl group having 4 or more carbon atoms is 50% by mass or higher among repeating units constituting the adhesive polymer.
　The adhesive composition according to any one of Claims 9 to 14, wherein a content of the conductive polymer is from 0.01 to 20 parts by mass relative to 100 parts by mass of the adhesive polymer.
　The adhesive composition according to any one of Claims 9 to 15, wherein a content of the amphiphilic compound is from 0.1 to 10 parts by mass relative to 100 parts by mass of the adhesive polymer.
　A protective material comprising:
　a substrate; and
　an adhesive layer provided on the substrate,
　wherein the adhesive layer includes: a (meth)acrylic adhesive polymer having the glass transition temperature of 0°C or lower; a conductive polymer containing a conjugated polymer and a polyanion; and an amphiphilic compound.
　The protective material according to Claim 17, wherein the amphiphilic compound contained in the adhesive layer is an ether or ester of a trivalent or more polyvalent alcohol or a nonionic compound having an oxyalkylene chain.
　The protective material according to Claim 17 or 18, wherein the haze of the adhesive layer is smaller than 5.
　The protective material according to any one of Claims 17 to 19, wherein the polyanion contained in the adhesive layer has a hydrogenated or unhydrogenated diene structure.
　The protective material according to any one of Claims 17 to 20, wherein the polyanion contained in the adhesive layer has a block structure.
　The protective material according to any one of Claims 17 to 21, wherein a rate of (meth)acrylic acid alkyl ester units having an alkyl group having 4 or more carbon atoms is 50% by mass or higher among repeating units constituting the adhesive polymer of the adhesive layer.
　The protective material according to any one of Claims 17 to 22, wherein a content of the conductive polymer in the adhesive layer is from 0.01 to 20 parts by mass relative to 100 parts by mass of the adhesive polymer.
　The protective material according to any one of Claims 17 to 23, wherein a content of the amphiphilic compound in the adhesive layer is from 0.1 to 10 parts by mass relative to 100 parts by mass of the adhesive polymer.