WO2023013315A1 - Polarizing sheet and method for manufacturing same - Google Patents

Polarizing sheet and method for manufacturing same Download PDF

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Publication number
WO2023013315A1
WO2023013315A1 PCT/JP2022/026041 JP2022026041W WO2023013315A1 WO 2023013315 A1 WO2023013315 A1 WO 2023013315A1 JP 2022026041 W JP2022026041 W JP 2022026041W WO 2023013315 A1 WO2023013315 A1 WO 2023013315A1
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WO
WIPO (PCT)
Prior art keywords
functional
sheet
layer
functional sheet
individual lens
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PCT/JP2022/026041
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French (fr)
Japanese (ja)
Inventor
雅幸 赤木
英明 木村
航太 岡崎
Original Assignee
三菱瓦斯化学株式会社
Мｇｃフィルシート株式会社
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Publication of WO2023013315A1 publication Critical patent/WO2023013315A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • 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
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
    • G02C7/00—Optical parts
    • G02C7/10—Filters, e.g. for facilitating adaptation of the eyes to the dark; Sunglasses

Definitions

  • the present invention provides a functional sheet for sunglasses in which a protective layer made of a transparent plastic sheet or film is laminated via an adhesive layer on at least one side of a functional layer that is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof, and functional lenses for sunglasses.
  • PVA polyvinyl alcohol-based film
  • a functional sheet is formed by laminating a transparent plastic sheet or film, especially an aromatic polycarbonate resin sheet, etc., and the functional sheet is heat-bent to improve durability.
  • a functional polycarbonate lens for sunglasses which is formed by inserting the heat-bent product into a mold to form an injection-molded lens, is widely used (Patent Document 1).
  • a functional layer such as PVA and a protective layer are laminated via an adhesive layer. Due to the high chemical resistance and barrier properties of polyamide resin, gas generated by the reaction between the functional layer and the protective layer may be trapped, which may cause appearance defects. Improvements have also been proposed (Reference 3).
  • a polarizing sheet made by laminating polycarbonate resin sheets as protective layers on both sides of a polarizing film is punched into a predetermined shape, and a drying process is performed to prevent color change in the process of forming a lens shape by thermal bending.
  • Patent Document 4 Patent Document 4 Therefore, when a polarizing laminate is produced by using a sheet made of polyamide resin, which has a higher hygroscopicity than polycarbonate resin, as a protective layer to produce an optically functional lens, the functional layer becomes more prominent in the heat bending process.
  • the inventors of the present application conducted intensive studies on the cause of this problem, and found that a polarizing laminate obtained by laminating a polyamide resin sheet on at least one side of an optical functional film via an adhesive layer was punched into a predetermined shape.
  • the "percentage of water content" in the polarized laminate before heat bending is 50% or less, and the water content is 15% or less in the drying process before heat bending. By doing so, it was found that color change can be suppressed to a small extent in any lens molded product.
  • the purpose of the present invention is to solve such problems.
  • the present invention provides a function in which a protective layer made of a transparent plastic sheet or film made of a polyamide resin is disposed on at least one side of a functional layer, which is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof, via an adhesive layer.
  • a functional layer which is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof, via an adhesive layer.
  • a method for manufacturing individual lens pieces from a flexible sheet comprising: a) A step of producing a functional sheet comprising a protective layer made of a transparent plastic sheet or film disposed on at least one side of a functional layer that is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof via an adhesive layer, b) storing the functional sheet so as not to absorb moisture; and c) punching the functional sheet into pieces for individual lenses.
  • the water content ratio of the functional sheet is 50% when the water content of the functional sheet saturated with water content is 100%.
  • the method further includes d) the step of thermally bending the individual lens piece, Manufacture of individual lens pieces, characterized in that, before performing the step of thermally bending the individual lens pieces in d), a further drying step is performed to reduce the moisture content to 15% or less.
  • a method is provided.
  • the transparent plastic sheet or film made of polyamide resin is made of amorphous or microcrystalline polyamide resin.
  • the adhesive layer is made of urethane resin adhesive.
  • the protective layer has a retardation value of 200 nm or less, 2000 nm or more, or a combination thereof.
  • Another embodiment of the present invention is characterized in that at least one side of the protective layer is not stretched.
  • Another embodiment of the present invention includes a step of heat-sealing a thermoplastic resin to the concave side of the heat-bent lens piece.
  • the present invention also provides a functional lens manufactured by any of the methods described above.
  • Sunglasses or goggles using such functional lenses are also within the scope of the present invention.
  • the present invention it is clear that in a functional sheet obtained by laminating a sheet made of a polyamide resin on a functional sheet with an adhesive layer interposed therebetween, it is preferable to store the functional sheet in a predetermined dry environment after manufacturing the functional sheet. became. Furthermore, it was found that it is necessary to carry out a drying process so that the water content is even lower before hot bending. Thus, in the present invention, it is possible to reduce the occurrence of defective products by appropriately controlling the moisture content of the functional sheet in the manufacturing process.
  • the polarizing film used for the functional layer is obtained by swelling a resin film as a base material in water and then impregnating it with a dyeing solution containing a dichroic organic dye while stretching it in one direction to obtain a dichroic dye. It is a film imparted with polarizing properties and a desired color tone by being dispersed in a base resin in an oriented state.
  • Polyvinyl alcohols are used as the base resin of the polarizing film used at this time, and the polyvinyl alcohols include polyvinyl alcohol (hereinafter referred to as PVA), PVA with a small amount of acetate ester structure remaining, and PVA derivatives or Analogues such as polyvinyl formal, polyvinyl acetal, and saponified ethylene-vinyl acetate copolymer are preferred, and PVA is particularly preferred.
  • PVA polyvinyl alcohol
  • the molecular weight of PVA is preferably a weight average molecular weight of 50,000 to 350,000, more preferably a molecular weight of 100,000 to 300,000, particularly a molecular weight of 150,000 or more, from the viewpoint of stretchability and film strength. is preferred.
  • the stretching ratio for stretching the PVA film is 2 to 8 times, preferably 3.5 to 6.5 times, and particularly 4.0 to 6.0 times in terms of the dichroic ratio and film strength after stretching. preferable.
  • the thickness of the PVA film after stretching is 10 ⁇ m or more, and the thickness is preferably 20 ⁇ m or more and about 50 ⁇ m or less because it can be handled without being integrated with a protective film or the like.
  • a typical manufacturing process when using a PVA film as the base film is (1) The PVA film is swollen in water and washed with water to appropriately remove impurities, (2) while stretching as appropriate, (3) Dyeing in a dyeing tank, (4) cross-linking or chelation treatment in a treatment tank with boric acid or a metal compound; (5) dry; Manufactured in the process of The steps (2), (3) (and (4) in some cases) may be changed in order, or may be carried out at the same time.
  • the PVA film which is easily broken in a dry state at room temperature, is uniformly softened and made stretchable by absorbing water. It is also a step of removing water-soluble plasticizers and the like used in the manufacturing process of the PVA film, or preliminarily adsorbing additives as appropriate. At this time, the PVA film does not gradually and uniformly swell, and variations always occur. Even in this state, it is important to apply a uniform force that is as small as possible so as to prevent local stretching or insufficient stretching and to suppress the occurrence of wrinkles. Moreover, in this step, it is most desirable to simply swell uniformly, and excessive stretching, etc., causes unevenness and should be avoided as much as possible.
  • step (2) stretching is usually carried out so as to be 2 to 8 times.
  • good workability is important, so the draw ratio is selected from 3.5 to 6.5 times, particularly 4.0 to 6.0 times, and the orientation is maintained even in this state. preferable.
  • the stretching process is set to be shorter.
  • Dyeing in step (3) is performed by adsorbing or depositing a dye onto the polymer chains of the oriented polyvinyl alcohol-based resin film. From this mechanism, it is possible before, during, and after uniaxial stretching, and there is no big difference. However, the interface, which is the highly regulated surface, is the most easily oriented, and it is preferable to select conditions that take advantage of this. .
  • the temperature is usually selected from a high temperature of 40 to 80°C from the requirement of high productivity, but in the present invention it is usually selected from 25 to 45°C, preferably 30 to 40°C, especially 30 to 35°C.
  • Step (4) is performed to improve heat resistance, water resistance, and organic solvent resistance.
  • the former treatment with boric acid improves the heat resistance by cross-linking between PVA chains.
  • the latter metal compound mainly forms a chelate compound with dye molecules to stabilize them, and is usually carried out after dyeing or at the same time as dyeing.
  • the metal compound there are transition metals belonging to any of the 4th, 5th, and 6th periods that are confirmed to have the heat resistance and solvent resistance effects described above.
  • Metal salts such as acetates, nitrates and sulfates of 4th period transition metals such as chromium, manganese, cobalt, nickel, copper and zinc are preferred from the viewpoint of cost.
  • compounds of nickel, manganese, cobalt, zinc and copper are more preferable because they are inexpensive and excellent in the above effects.
  • the content of the metal compound and boric acid in the polarizing film is 0.2 to 20 mg of the metal compound per 1 g of the polarizing film. Preferably, 1 to 5 mg is more preferable.
  • the boric acid content is preferably 0.3 to 30 mg, more preferably 0.5 to 10 mg as boron.
  • the composition of the treatment liquid used for the treatment is set so as to satisfy the above contents, and generally the concentration of the metal compound is 0.5 to 30 g/L and the concentration of boric acid is 2 to 20 g/L. preferable.
  • the content of metal and boron contained in the polarizing film can be analyzed by atomic absorption spectrometry.
  • the temperature is usually the same as for dyeing, but is usually selected from 20 to 70°C, preferably 25 to 45°C, more preferably 30 to 40°C, especially 30 to 35°C. Also, the time is usually selected from 0.5 to 15 minutes.
  • step (5) the stretched, dyed and optionally dyed uniaxially stretched PVA film treated with boric acid or metal compound is dried.
  • a PVA film exhibits heat resistance corresponding to the amount of water it contains. A loss of color ratio occurs. Drying proceeds from the surface, and it is preferable to dry from both surfaces, preferably while removing water vapor by blowing dry air.
  • the method of immediately removing the evaporated moisture to promote evaporation is preferable from the point that drying can be performed while suppressing the temperature rise.
  • Air drying is carried out at a temperature of 70° C. or higher, preferably 90° C. to 120° C., for 1 to 120 minutes, preferably 3 to 40 minutes, from the temperature range below which the film does not substantially discolor.
  • the moisture content of PVA after drying is usually 1 to 4 wt%.
  • a light control film in which a light control dye is kneaded into a urethane film can be suitably used.
  • a photochromic dye may be kneaded into the adhesive layer, which will be described later.
  • a photochromic compound-containing thermosetting polyurethane resin layer can be produced by the following method.
  • the photochromic dye (photochromic compound) is not particularly limited as long as it is compatible with the polyurethane prepolymer, and commercially available organic photochromic compounds can be used. Spiropyran-based compounds, spirooxazine-based compounds and naphthopyran-based compounds are preferably used in terms of photochromic performance.
  • a method for manufacturing a light control film used for the light control layer is exemplified.
  • a photochromic compound is added to a solution obtained by diluting a polyurethane prepolymer with a specific organic solvent in a proportion of 0.2 to 5% by weight relative to the resin solid content, and a hindered amine is added in an amount of 0.1 to 5% by weight relative to the resin solid content.
  • Additives such as light stabilizers and/or antioxidants for the system are added and uniformly stirred and mixed.
  • a curing agent is further added so that the ratio I/H of the isocyanate group (I) to the hydroxyl group (H) of the curing agent is 0.9 to 20, preferably 1 to 10, and the mixture is further stirred to form a solution.
  • a suitable polymer concentration in the solution is generally 40 to 90% by weight.
  • the solution is applied to the back surface of a transparent polycarbonate sheet having a coating layer on its surface using a doctor blade with a coating thickness of 50 to 1000 ⁇ m. After coating, the coated surface is dried by heating until it does not substantially contain a solvent, and the coated surface of the synthetic resin sheet is laminated with the back surface of a transparent polycarbonate sheet provided with a coating layer on the other surface to form a sandwich. and then left to dry to obtain a light control film.
  • Adhesion layer In order to laminate the functional layer and the protective layer to form a functional sheet, an adhesive layer is interposed between the functional layer and the protective layer.
  • Adhesive materials usually used for functional sheets include polyvinyl alcohol resin-based materials, acrylic resin-based materials, urethane resin-based materials, polyester resin-based materials, melamine resin-based materials, epoxy resin-based materials, and silicone-based materials.
  • a thermosetting material is preferable from the viewpoint of stability in thermal bending and injection molding processes, and in particular, a two-liquid type thermosetting urethane consisting of a polyurethane prepolymer, which is a urethane resin material, and a curing agent. Resins are preferred.
  • the polyurethane prepolymer is a compound obtained by reacting a diisocyanate compound and a polyoxyalkylenediol at a constant ratio and having isocyanate groups at both ends.
  • Diisocyanate compounds used in polyurethane prepolymers include diphenylmethane-4,4′-diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, lysine isocyanate, and hydrogenated xylylene diisocyanate.
  • Isocyanates can be used, but diphenylmethane-4,4'-diisocyanate is preferred.
  • Polypropylene glycol, polyethylene glycol, and polyoxytetramethylene glycol can be used as the polyoxyalkylene diol, and it is preferable to use polypropylene glycol having a degree of polymerization of 5-30.
  • the molecular weight of the polyurethane prepolymer is not particularly limited, it usually has a number average molecular weight of 500 to 5,000, preferably 1,500 to 4,000, and more preferably 2,000 to 3,000.
  • the curing agent is not particularly limited as long as it is a compound having two or more hydroxyl groups.
  • Polyurethane polyols having terminal hydroxyl groups obtained from specific isocyanates and specific polyols are preferred.
  • Particularly preferred is a polyurethane polyol derived from a diisocyanate compound and a polyol and having hydroxyl groups at least at both ends.
  • Diphenylmethane-4,4'-diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, lysine isocyanate, and hydrogenated xylylene diisocyanate can be used as the diisocyanate compound.
  • the polyol a product obtained by reacting trimethylolpropane or the like with ethylene oxide or propylene oxide can be used, and it is preferable to use a polypropylene glycol derivative having a degree of polymerization of 5 to 30.
  • the molecular weight of this curing agent is not particularly limited, the number average molecular weight is usually 500-5000, preferably 1500-4000, more preferably 2000-3000.
  • These polyurethane prepolymers and curing agents can use solvents such as ethyl acetate and tetrahydrofuran for viscosity control.
  • solvents such as ethyl acetate and tetrahydrofuran for viscosity control.
  • the use of a solvent is an effective method for uniformly dispersing the photochromic compound in the urethane resin.
  • the functional sheet used for the individual lens pieces of the present invention has a protective layer (or a protective film or a protective film for polarizing film) made of a polyamide resin formed on at least one surface thereof.
  • the polyamide resin is preferably amorphous polyamide or microcrystalline polyamide from the viewpoint of transparency and molding processability, and preferably can be injection molded as described later. That is, any material can be suitably used as long as it is thermoplastic, exhibits moldable melt fluidity at a temperature below the thermal decomposition temperature, and has an appropriate Tg (glass transition temperature).
  • cycloalkanes are used.
  • a structure with a large enthalpy in the repeating unit (unit molecular chain length) and a structure that restricts molecular movement within the repeating unit and between repeating units are essential, and a typical example of the former is It is aromatic, and in the latter example, cycloalkane, cycloalkene, etc. having a structure obtained by hydrogenating the unsaturated bond of the aromatic nucleus are used.
  • Aromatic polyamides and alicyclic polyamides are, in principle, produced by making aromatic or alicyclic constitutional units derived from at least one type of monomer constituting the wholly aliphatic polyamide.
  • Partially aromatic polyamide, partially aromatic alicyclic polyamide, partially aromatic alicyclic polyamide, partially aromatic alicyclic polyamide, partially alicyclic Polyamides and the like, or combinations thereof, can be used in the present invention, but as one typical example of amorphous polyamides having amorphous properties and moderate heat resistance, polyamides having an alicyclic structure are preferably used. be able to. In consideration of optical properties such as retardation, which will be described later, it is desirable to include an aromatic moiety. Naturally, additives such as lubricants and antioxidants are appropriately used in the polyamide resin used in the present invention in order to deal with oxidative deterioration of polyamide, processing defects, and the like.
  • thermoplastic resin is integrated on the concave side by injection fusion to form a polyamide functional sheet.
  • optical distortion may occur. That is, when viewed obliquely, iridescent "color unevenness" is observed, or when the curved polarizing plate is superimposed on a plane polarizing plate arranged so that the polarization axes are orthogonal to each other, the light is A so-called "polarization leakage" that is transmitted may be observed.
  • the retardation value increases (for example, 300 nm to 1200 nm), disturbs the polarization of the polarizing film layer provided in the inner layer, and causes the above-described "polarization leakage" on the surface that becomes the concave surface of the lens after processing. A defect is observed. Also, on the convex surface, colored interference fringes are observed as "color unevenness" when obliquely observed.
  • the protective layer has a retardation value (for example, 300 nm or less, preferably 200 nm or less, more preferably 100 nm or less) that does not hinder the function of the polarizing film layer provided in the inner layer. It is desirable to arrange it in a convex position. For such low retardation, the thickness of the protective layer is desirably 100 ⁇ m or less, preferably 80 ⁇ m or less.
  • a film manufactured by a casting method or the like which is less likely to promote molecular orientation, can be suitably used as a protective layer.
  • a protective layer with an extremely large retardation value for example, 1300 nm or more, preferably 2000 nm or more, more preferably 3000 nm or more, is arranged on the convex surface after processing into a lens.
  • an extremely large retardation value for example, 1300 nm or more, preferably 2000 nm or more, more preferably 3000 nm or more.
  • the retardation value is an in-plane retardation value.
  • the in-plane retardation value can be derived from the refractive index in the slow axis direction, the refractive index in the fast axis direction, and the thickness of the film when the incident linearly polarized light is resolved into the slow axis and the fast axis. It is within my knowledge.
  • the retardation value is a value measured at 590 nm.
  • a measuring device there is a retardation measuring device: RETS-100 manufactured by Otsuka Electronics.
  • Examples of stretching a film molded by a melt extrusion method to increase the retardation value include a draw-stretching method in which the film is pulled out while being stretched, and an off-line stretching method in which the film is wound once after molding and then stretched separately.
  • a polyamide sheet can be produced by melt-mixing the polyamide resin or the resin constituting the protective layer with an extruder or the like, extruding the mixture from a die (eg, a T-die), and cooling.
  • the resin temperature when the polyamide resin or the resin constituting the protective layer is melted and molded (melt molding) can usually be selected from a temperature range of about 120 ° C.
  • the drawing process can be performed by making the take-up speed faster than the speed of the cooling rolls.
  • the specific stretching method is not particularly limited as long as it does not impair the performance of the functional sheet of the present invention.
  • the resin temperature of the rolls in the stretching portion is kept constant while the rolls are appropriately heated by a mold temperature controller or the like.
  • stretching is performed in a temperature range in which the resin temperature is lower than the Tg of the polyamide resin to be used, uneven stretching is likely to occur, resulting in an uneven pattern between stretched and non-stretched portions.
  • the Tg referred to in the present invention indicates the temperature at the middle point among the temperatures at the start point, the middle point, and the end point in the Tg curve measured by DSC.
  • the resin temperature of the protective layer sheet during stretching is also related to imparting of retardation. If the resin temperature of the film or sheet during stretching is lower than the Tg of the resin being used, it is easier to impart higher retardation if the stretching process is performed. It becomes difficult. Furthermore, it is preferable to cool the film as quickly as possible after stretching so that the retardation and the angle between the slow and fast axes can be fixed. Moreover, when the sheet is stretched in a temperature range lower than the Tg, problems such as shrinkage may occur after sheet molding, so it is essential to select the stretching temperature conditions in consideration of this point.
  • the intrinsic birefringence value varies depending on the composition of the polyamide resin, and it also depends on the desired retardation value, so it is essential to appropriately adjust the draw ratio in the drawing process. In general, at least 1.1 times, preferably 1.2 times, more preferably 1.3 times or more is required. The higher the magnification, the more neck-in is promoted, or the risk of breakage occurs, so the upper limit is determined from the viewpoint of production efficiency. It is usually about 2.2 times, preferably about 2.0 times or less.
  • Polyamide resins are known to have higher hygroscopicity than aromatic polycarbonate resins, which have been generally used as protective layers for polarizing sheets for sunglasses.
  • the polyamide resin protective layer produced by melt-extrusion of the polyamide resin also has high hygroscopicity.
  • the fact that the optical function layer is affected by moisture is the same when the aromatic polycarbonate resin is used as the protective layer. It is thought that it can be handled by performing sufficient drying before bending. However, as will be described later, in the present invention, even if the drying is sufficiently performed only before the heat bending process, it is insufficient, and it is impossible to maintain a predetermined dry state even after forming the laminate. was necessary.
  • a polyamide resin with a high degree of crystallinity generally has high shape stability and therefore low hygroscopicity.
  • an amorphous or microcrystalline polyamide resin from the viewpoint of transparency, workability, and gas barrier properties.
  • Polyamide resins with a highly regular structure such as polyamides containing terephthalic acid (1,4-dicarboxybenzene) and 1,4-diaminobenzene as monomers, have flat and identical bonds. Since it is arranged on a plane, it is easy to form aggregates with high regularity and low gas permeability, so gas barrier properties tend to be high.
  • the composition of the polyamide resin sheet must be selected taking this point into consideration.
  • the gas barrier properties of the protective layer are greatly affected by the thickness of the protective layer and the stretching conditions. Even if the protective layer has a gas barrier property that does not generate air bubbles in an unstretched state, the higher the draw ratio, the more the molecular orientation is promoted. may exhibit gas barrier properties that generate As for the gas barrier property, the oxygen permeability can be measured according to DIS/ISO 15105-1.
  • the thickness and degree of stretching of the protective layer can be determined in consideration of the specifications and oxygen permeability of the final product.
  • the oxygen permeability of the protective layer is about 10 cm 3 /m 2 ⁇ 24 hr ⁇ bar at 23°C and 85% RH, the generation of air bubbles is significant and the functional sheet cannot be used.
  • the oxygen permeability of the protective layer is 50 cm 3 /m 2 ⁇ 24 hr ⁇ bar or more, 60 cm 3 /m 2 ⁇ 24 hr ⁇ bar or more, 70 cm 3 /m 2 ⁇ 24 hr ⁇ bar or more.
  • 90 cm 3 /m 2 ⁇ 24 hr ⁇ bar or more 110 cm 3 /m 2 ⁇ 24 hr ⁇ bar or more, 130 cm 3 /m 2 ⁇ 24 hr ⁇ bar or more, 150 cm 3 /m 2 ⁇ 24 hr ⁇ bar or more.
  • it may be 400 cm 3 /m 2 .24 hr.bar or more, 410 cm 3 /m 2 .24 hr.bar or more, 420 cm 3 /m 2 .24 hr.bar or more, or 430 cm 3 /m 2 .24 hr.bar or more. .
  • the upper limit of the oxygen permeability of the protective layer is not particularly important as long as the protective layer allows good lens molding. It is necessary to select a combination of conditions such as the resin composition, the thickness of the protective layer, and the stretching treatment, taking this point into consideration.
  • the effect of the invention is judged based on the moisture content of the functional sheet, but the effect of the present invention is considered to be largely due to the hygroscopicity of the polyamide resin.
  • a functional sheet having a sheet made of a polycarbonate resin as a protective layer even in a high moisture content state of about 60% to 70% of the saturated state before bending, it is possible to prevent heat from bending. It has been found that by reducing the water content to a certain level or less, problems during hot bending can be eliminated.
  • the saturated state of water in the entire polarizing laminate is defined as wt % of the water content, and the water content is compared with this to obtain the "percentage of water content". That is, the "moisture content" of the functional sheet in a saturated state of hygroscopicity is used as a reference.
  • the water content is considered to be affected by the resin constituting the functional sheet and the material and amount of the functional layer.
  • the water content ratio may be 70% or less, 60% or less, preferably 50% or less, preferably 40% or less, with respect to the water content in the saturated state. was confirmed to be preferable. Furthermore, the percentage of the moisture content is preferably 30% or less, 20% or less, or 15% or less before hot bending, and preferably reduced to about 10%. It was confirmed that it is necessary to suppress the change.
  • the polarizing film layer is used as a functional layer, the adhesive layer is applied with a gravure coater or a die coater, the protective layer is attached to both sides, and the sheet is cut to a desired length to form a functional sheet. can be done.
  • the lamination method is not particularly limited, but a sufficient discharge amount is maintained in order to avoid entrainment of air bubbles due to lack of the coating liquid during coating of the adhesive. Moreover, it is desirable to appropriately adjust the tension during lamination, the nip pressure of the lamination roll, and the like, taking into account the state of warpage of the sheet after lamination.
  • the functional sheet is punched out into individual lens pieces, the obtained individual lens pieces are curved, and if necessary, they are inserted into an injection molding machine and a thermoplastic resin is injected onto the concave side of the individual lens pieces.
  • functional lenses for punching, a punching blade, usually a Thomson blade, can be used.
  • a plurality of individual lens pieces are usually obtained by punching from one functional sheet.
  • the shape of the individual lens piece is appropriately selected according to the shape of the final product (sunglasses, goggles, etc.).
  • a standard lens-shaped product for binocular use is a disk with a diameter of 80 mm or a slit shape obtained by cutting both ends of the disk with the same width in the direction perpendicular to the polarization axis.
  • the polarizing film layer, the adhesive layer, the protective layers on both surfaces, and the protective films on both surfaces are not greatly destroyed, and the generation of fine fragments, the propagation of cracks in the stretching direction, and excessive
  • the presence or absence of deformation elongation is an object of examination, and appropriate tenacity is essential.
  • the individual lens piece is pre-dried and then thermally bent into a spherical or aspherical surface under heating to form a thermally bent sheet.
  • the pre-drying conditions are selected that do not change the color after the individual lens piece is thermally bent. Usually, it is dried at 60 to 80° C., preferably 65 to 75° C. for 8 hours or more, preferably about 24 hours.
  • the thermal bending process of the individual lens piece is bent along the mold surface.
  • the mold may be a mold used for injection molding.
  • Thermal bending is the process of converting a planar individual lens piece into a three-dimensional curved surface, usually a partial spherical surface, and possibly an ellipsoidal surface. Such processing with minimal energy associated with deformation results in shrinkage, and if smooth shrinkage is hindered, waves and wrinkles occur, making it impossible to manufacture good products. It is preferable to control the temperature, the loading of the load, etc.
  • a processing temperature is selected that is at least 50° C. lower than the glass transition point of the polyamide resin used for the protective sheet and below the glass transition point. It is preferably at least 25°C lower than the glass transition temperature of the polyamide resin, more preferably at least 20°C lower than the glass transition temperature and at most 5°C lower than the glass transition point.
  • Processing conditions for injection molding must be such that lenses with excellent appearance can be produced. Therefore, the injection conditions such as injection pressure, holding pressure, metering, molding cycle, etc., are appropriately selected so that a lens molded product with a high filling rate can be obtained within a range in which burrs do not occur.
  • the resin temperature is usually appropriately selected from 230 to 320°C, preferably 250 to 300°C, although it depends on the melting temperature of the polyamide resin and the composition of the polyamide resin.
  • the injection pressure is appropriately selected from 50 to 200 MPa.
  • the mold temperature is selected from a temperature not less than 100°C lower than the Tg of the polyamide resin and less than the Tg, preferably 70 to 120°C.
  • the thermoplastic resin used for injection molding is preferably a polyamide resin, more preferably a so-called amorphous polyamide. It is thermoplastic, exhibits moldable melt fluidity below the thermal decomposition temperature, and has an appropriate Tg (glass transition temperature). It is preferable to select a polyamide resin having a refractive index that is the same as or close to that of the polyamide resin used for the optical sheet.
  • the functional lens manufactured as described above is appropriately subjected to a hard coating treatment, and further subjected to a mirror coating, an antireflection coating, or the like, to obtain a product.
  • the material and processing conditions of the hard coat must be excellent in appearance and adhesion to the underlying polyamide, or to the subsequently coated inorganic layer such as mirror coat or antireflection coat.
  • the baking temperature of the coat is preferably at least 50°C lower than the glass transition point of the polyamide resin and lower than the glass transition point, particularly at least 40°C lower than the glass transition point and lower than 15°C lower than the glass transition point. is more preferable, and a temperature lower than about 30°C is most preferable.
  • the firing time of the hard coat is approximately 0.5 to 2 hours.
  • the functional lenses manufactured above are processed into final products such as sunglasses and goggles by lens manufacturers and sold. Lens processing is done for various products such as, and sold as sunglasses and goggles.
  • a drying process was performed at 70°C for 20 hours.
  • the specimens of the comparative examples were heated at 70° C. or 80° C. for 4 to 20 hours.
  • This dyed film was immersed in an aqueous solution containing 2.3 g/L of nickel acetate and 4.4 g/L of boric acid at 35° C. for 120 seconds while being stretched 4 times.
  • the film was dried at room temperature for 3 minutes while being kept in tension, and then heat-treated at 110° C. for 3 minutes to obtain a polarizing film.
  • C Polyvinyl alcohol manufactured by Kuraray Co., Ltd., trade name: VF-PE#6000 was swelled in water at 35° C. for 270 seconds while being stretched twice.
  • Table 1 shows the dichroic ratio of the obtained polarizing film at light absorption wavelengths of blue (450 nm), green (550 nm) and red (650 nm).
  • the dichroic ratio was obtained by the following formula.
  • Dichroic ratio Az/Ax
  • Ax represents the absorbance of linearly polarized light in the maximum transmission direction
  • Az represents the absorbance of linearly polarized light in the direction orthogonal to the maximum transmission direction.
  • Ax and Az were measured using a spectrophotometer (UV-3600 manufactured by Shimadzu Corporation) by illuminating the sample with linearly polarized light.
  • Table 1 shows the degree of polarization of the obtained polarizing film and the color tone when arranged in crossed Nicols.
  • the degree of polarization was determined by the following formula.
  • Degree of polarization 100 ⁇ ( ⁇ pmax- ⁇ pmin) / ( ⁇ pmax + ⁇ pmin)
  • ⁇ pmax represents the maximum value of luminous transmittance measured with incident linearly polarized light
  • ⁇ pmin represents the minimum value of luminous transmittance measured with incident linearly polarized light
  • ⁇ pmax and ⁇ pmin are values representing Ax and Az as luminous transmittance.
  • the color tone in the crossed nicols arrangement can be expressed by Az ⁇ Ax because the light incident on the polarizing film is absorbed by the transmission axis and the absorption axis in the crossed nicols arrangement, respectively. Calculated using the L*a*b* color system.
  • the color tone in the crossed nicols configuration has a low b* value and looks bluish, but the degree of polarization exceeds 99%, and there is no practical problem.
  • a polyvinyl alcohol film manufactured by Kuraray Co., Ltd.
  • dichroic dyes Summit Supra Blue G C.I.
  • PA1 (Production of polyamide sheet) (PA1): Aliphatic and alicyclic amorphous transparent polyamide resin (EMS-CHEMIE, Grilamid TR90) is heated and melted, the molten resin is extruded from a T-die with a short screw extruder, and cooled with a cooling roll.
  • a non-stretched polyamide sheet (hereinafter referred to as PA1) having a Tg of 155° C., a thickness of 300 ⁇ m, and a retardation of 50 nm was produced by a melt extrusion method in which the sheet was later wound up with a winder. All the produced polyamide sheets were stored in a low-humidity storage immediately after production.
  • PA2 A polyamide sheet obtained in the same manner as PA1 except that the thickness was 530 ⁇ m was cut into 10 cm squares, fixed on all sides with clamps, and held at the Tg (middle point in DSC measurement) temperature of PA1 for 20 minutes. , stretched only in the uniaxial direction at a draw ratio of 1.5 times, and cooled at room temperature for 30 minutes while maintaining the tension after stretching to obtain a stretched polyamide sheet (hereinafter referred to as PA2) having a retardation of 4000 nm. .
  • the oxygen permeability was measured at 23° C. and 85% RH using OX-TRAN 2/61 (manufactured by MOCON).
  • the retardation value is a value measured at a wavelength of 590 nm using a retardation measuring device: RETS-100 manufactured by Otsuka Electronics.
  • thermosetting polyurethane adhesive was applied to PA1 obtained above, the polarizing film obtained above was laminated, and PA2 was laminated in the same manner on the remaining one side of the polarizing film. After lamination, the adhesive was cured by standing in a constant temperature bath at 70° C. to obtain a functional sheet.
  • the obtained functional sheets were stored in a laminated state in a room controlled at 25° C. ( ⁇ 5° C.) and humidity of 10% ( ⁇ 5 to +10%).
  • the functional sheet obtained above was cut from a disk with a diameter of 80 mm into a slit shape with a width of 55 mm by cutting the same amount in parallel on both sides of a straight line passing through the center, and the color tone was measured. (Measurement of moisture content)
  • the pieces for individual lenses were allowed to absorb moisture for two weeks in a room controlled at 40°C and 90%. Whether or not the moisture absorption reached saturation was confirmed by measuring several times after two weeks. confirmed to be reached.
  • the female mold Pre-heating at an ambient temperature of 125°C, the female mold has a partial spherical surface equivalent to 6R (radius of about 65.6 mm), the surface temperature is 135°C, the pressing time with the silicone rubber male mold is 4 seconds, and the female mold is vacuumed. It was made to adsorb and held for 8 minutes in an atmosphere with a hot air blowing temperature of 150° C. to prepare a thermal bending individual lens piece, and the color tone was measured.
  • the individual lens piece made of the polyamide polarizing laminate before the drying process has a moisture content of 50% or less before the drying process.
  • the water content By setting the water content to 15% or less before bending the individual lens pieces, it is possible to produce individual lens pieces with little color difference due to thermal bending.

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Abstract

[Problem] To prevent color change during heat bending of an individual-lens piece that comprises a functional sheet on which a protective layer formed from a transparent plastic sheet or film comprising a polyamide resin is disposed. [Solution] Provided is a method for manufacturing an individual-lens piece from a functional sheet obtained by arranging a protective layer formed from a transparent plastic sheet or film via an adhesive layer on at least one side of a functional layer which is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof, wherein the method for manufacturing an individual-lens piece is characterized by including: a) a step for manufacturing a functional sheet obtained by arranging a protective layer formed from a transparent plastic sheet or a film via an adhesive layer on at least one side of a functional layer which is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof; b) a step for storing the functional sheet so that the functional sheet does not absorb moisture; and c) a step for stamping out the functional sheet into an individual-lens piece, the functional sheet being stored so that the moisture content ratio thereof does not exceed 50%, where 100% is the moisture content of the functional sheet when the moisture content is saturated, from step b) for storing the functional sheet so that the functional sheet does not absorb moisture to step c) for stamping out the functional sheet into an individual-lens piece.

Description

偏光シートおよびその製造方法Polarizing sheet and manufacturing method thereof
　本発明は、ポリビニルアルコール系偏光フィルム層、調光層またはこれらの組み合わせである機能層の少なくとも片面に、透明プラスチックシート或いはフィルムによる保護層が接着層を介して積層されたサングラス用機能性シート、及びサングラス用機能性レンズに関するものである。 The present invention provides a functional sheet for sunglasses in which a protective layer made of a transparent plastic sheet or film is laminated via an adhesive layer on at least one side of a functional layer that is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof, and functional lenses for sunglasses.
　ポリビニルアルコール系フィルム（以下、ＰＶＡ）を二色性色素により染色してなる偏光フィルムや調光色素をマトリックス樹脂中に分散させた調光層、若しくはそれらを組み合わせた機能層に、二液性の熱硬化型樹脂などを接着剤として用い、透明プラスチックシート或いはフィルム、特に、芳香族ポリカーボネート樹脂シートなどに積層させた機能性シートとし、該機能性シートを熱曲げ加工した後に、耐久性を向上させる観点から前記熱曲げ加工品を金型にインサートして射出成形レンズとするサングラス用機能性ポリカーボネートレンズは一般に普及している（特許文献１）。 A polarizing film made by dyeing a polyvinyl alcohol-based film (hereinafter referred to as PVA) with a dichroic dye, a light control layer in which a light control dye is dispersed in a matrix resin, or a functional layer combining them Using a thermosetting resin or the like as an adhesive, a functional sheet is formed by laminating a transparent plastic sheet or film, especially an aromatic polycarbonate resin sheet, etc., and the functional sheet is heat-bent to improve durability. From this point of view, a functional polycarbonate lens for sunglasses, which is formed by inserting the heat-bent product into a mold to form an injection-molded lens, is widely used (Patent Document 1).
　これら機能性ポリカーボネートレンズは、酢酸セルロースなどの可塑剤を含むプラスチックで形成されるメガネフレームに使用された場合、メガネフレーム中の可塑剤がブリードアウトして、ポリカーボネート樹脂で構成されるレンズにクラックを生じさせるなどの課題が指摘されている。これらの状況から、ポリアミド樹脂からなるシートを延伸してリタデーションを付与して保護層としたサングラス用偏光性積層体などが開示されている（特許文献２）。 When these functional polycarbonate lenses are used in spectacle frames made of a plastic containing a plasticizer such as cellulose acetate, the plasticizer in the spectacle frame bleeds out, causing cracks in the lenses made of polycarbonate resin. Issues such as causing In view of these circumstances, a polarizing laminate for sunglasses and the like, which is a protective layer formed by stretching a polyamide resin sheet to impart retardation, and the like have been disclosed (Patent Document 2).
　このようなポリアミド樹脂からなるシートを延伸してリタデーションを付与して保護層としたサングラス用偏光性積層体において、ＰＶＡなどの機能層と保護層とが接着層を介して積層して製造される。ポリアミド樹脂は耐薬品性およびバリア性も高いため、機能層と保護層との反応により生じた気体が閉じ込められることによる外観不具合も生じることもあるが、酸素透過度を指標にガスバリア性をコントロールし改善することも提案されている（引用文献３）。 In a polarizing laminate for sunglasses having a protective layer formed by stretching a sheet made of such a polyamide resin to impart retardation, a functional layer such as PVA and a protective layer are laminated via an adhesive layer. . Due to the high chemical resistance and barrier properties of polyamide resin, gas generated by the reaction between the functional layer and the protective layer may be trapped, which may cause appearance defects. Improvements have also been proposed (Reference 3).
特開平８－３１３７０１号JP-A-8-313701 特許第４３７９９５０号Patent No. 4379950 再表２０１９／０１３０７８号Retable No. 2019/013078 再表２０１４／０３０６１１号Retable No. 2014/030611
　前述のように、ポリアミド樹脂からなるシートを保護層とする光学機能性シートに対する需要が存在する。しかしながら、ポリカーボネート樹脂からなる保護層と比較して、ポリアミド樹脂は吸湿性が高いことが知られている。このことから当然に、ポリアミド樹脂からなる保護シートは、ポリカーボネート樹脂からなるシートに比べて、寸法安定性も劣る。その結果、最終製品における光学的機能性に対する影響も懸念される。 As mentioned above, there is a demand for an optical functional sheet with a sheet made of polyamide resin as a protective layer. However, polyamide resins are known to have higher hygroscopicity than protective layers made of polycarbonate resins. As a matter of course, a protective sheet made of a polyamide resin is inferior in dimensional stability to a sheet made of a polycarbonate resin. As a result, there is also concern about the impact on the optical functionality of the final product.
　ポリカーボネート樹脂からなるシートを保護層として偏光フィルムの両側に積層してなる偏光シートを所定の形状に打ち抜き、熱曲げ加工によりレンズ形状とする工程において、色変化を防ぐために、乾燥工程を施している（特許文献４）。従って、ポリカ―ボネート樹脂よりも吸湿性の高いポリアミド樹脂からなるシートを保護層として偏光性積層体を製造し、光学機能性レンズを製造する場合には、熱曲げ加工において、より顕著に機能層に色変化が生じることが予測される。本願発明者らは、このような予測される不具合を実際に確認し、これを防ぐため、ポリアミド樹脂からなるシートを保護層として積層されてなる機能性シートにおいて、熱曲げ加工前に十分な乾燥を行って機能性シートを製造した。しかしながら、ポリアミド樹脂からなるシートを保護層として積層されてなる機能性シートは、熱曲げ加工の後においては、十分な乾燥を行っても色変化が生じたレンズ成形品が一定程度製造されることが確認された。 A polarizing sheet made by laminating polycarbonate resin sheets as protective layers on both sides of a polarizing film is punched into a predetermined shape, and a drying process is performed to prevent color change in the process of forming a lens shape by thermal bending. (Patent Document 4). Therefore, when a polarizing laminate is produced by using a sheet made of polyamide resin, which has a higher hygroscopicity than polycarbonate resin, as a protective layer to produce an optically functional lens, the functional layer becomes more prominent in the heat bending process. It is expected that a color change will occur in The inventors of the present application actually confirmed such a predicted problem, and in order to prevent it, in a functional sheet formed by laminating a sheet made of a polyamide resin as a protective layer, sufficient drying is performed before heat bending. was performed to produce a functional sheet. However, functional sheets laminated with a sheet made of polyamide resin as a protective layer may produce a certain degree of lens molded products with color change even after sufficient drying after thermal bending. was confirmed.
　本願発明者らは、この原因について鋭意検討した結果、ポリアミド樹脂からなるシートに接着層を介して光学機能性フィルムの少なくとも片面に積層してなる偏光積層体を所定の形状に打ち抜き加工を施し、熱曲げしてなるサングラス用偏光レンズにおいて、熱曲げ加工前までの偏光積層体における「含水率の割合」を５０％以下とし、熱曲げ加工前の乾燥工程において、含水率の割合を１５％以下とすることにより、いずれのレンズ成形品においても色変化を少なく抑えることができることを見いだした。 The inventors of the present application conducted intensive studies on the cause of this problem, and found that a polarizing laminate obtained by laminating a polyamide resin sheet on at least one side of an optical functional film via an adhesive layer was punched into a predetermined shape. In the heat-bent polarizing lens for sunglasses, the "percentage of water content" in the polarized laminate before heat bending is 50% or less, and the water content is 15% or less in the drying process before heat bending. By doing so, it was found that color change can be suppressed to a small extent in any lens molded product.
　本発明は、かかる課題を解決することを目的とする。 The purpose of the present invention is to solve such problems.
　本発明は、ポリビニルアルコール系偏光フィルム層、調光層またはこれらの組み合わせである機能層の少なくとも片面に接着層を介して、ポリアミド樹脂からなる透明プラスチックシート或いはフィルムによる保護層が配置されてなる機能性シートから、個別レンズ用片を製造する方法であって、
ａ）ポリビニルアルコール系偏光フィルム層、調光層またはこれらの組み合わせである機能層の少なくとも片面に接着層を介して透明プラスチックシート或いはフィルムによる保護層が配置されてなる機能性シートを製造する工程、
ｂ）前記機能性シートを吸湿しないよう保管する工程、および
ｃ）前記機能性シートを個別レンズ用片に打ち抜く工程、を含み
ｂ）の前記機能性シートを吸湿しないよう保管する工程からｃ）の前記機能性シートを前記機能性シートを個別レンズ用片に打ち抜く工程において、水分含量を飽和させた機能性シートの含水率を１００％としたとき、前記機能性シートの含水率の割合が５０％を超えないように保管することを特徴とする、個別レンズ用片の製造方法が提供される。 The present invention provides a function in which a protective layer made of a transparent plastic sheet or film made of a polyamide resin is disposed on at least one side of a functional layer, which is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof, via an adhesive layer. A method for manufacturing individual lens pieces from a flexible sheet, comprising:
a) A step of producing a functional sheet comprising a protective layer made of a transparent plastic sheet or film disposed on at least one side of a functional layer that is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof via an adhesive layer,
b) storing the functional sheet so as not to absorb moisture; and c) punching the functional sheet into pieces for individual lenses. In the step of punching the functional sheet into individual lens pieces, the water content ratio of the functional sheet is 50% when the water content of the functional sheet saturated with water content is 100%. There is provided a method for manufacturing individual lens pieces, characterized in that they are stored so as not to exceed .
　本発明の１つの実施態様では、更に、ｄ）前記個別レンズ用片を熱曲げ加工する工程、を含み、
ｄ）の前記個別レンズ用片を熱曲げ加工する工程を行う前に、前記含水率の割合を１５％以下にするための更なる乾燥工程を行うことを特徴とする、個別レンズ用片の製造方法が提供される。 In one embodiment of the present invention, the method further includes d) the step of thermally bending the individual lens piece,
Manufacture of individual lens pieces, characterized in that, before performing the step of thermally bending the individual lens pieces in d), a further drying step is performed to reduce the moisture content to 15% or less. A method is provided.
　本発明の１つの実施形態では、ポリアミド樹脂からなる透明プラスチックシート或いはフィルムは非晶性或いは微結晶性ポリアミド樹脂からなる。 In one embodiment of the present invention, the transparent plastic sheet or film made of polyamide resin is made of amorphous or microcrystalline polyamide resin.
　本発明の他の実施形態では、接着層はウレタン樹脂系接着剤からなる。 In another embodiment of the present invention, the adhesive layer is made of urethane resin adhesive.
　本発明の他の実施形態では、保護層のリタデーション値は２００ｎｍ以下、２０００ｎｍ以上、或いはこれらの組み合わせである。 In other embodiments of the present invention, the protective layer has a retardation value of 200 nm or less, 2000 nm or more, or a combination thereof.
　本発明の他の実施形態では、保護層の少なくとも片面が延伸処理されていないことを特徴とする。 Another embodiment of the present invention is characterized in that at least one side of the protective layer is not stretched.
　本発明の他の実施形態では、熱曲げ加工されたレンズ用片の凹面側に熱可塑性樹脂を熱融着する工程を含む。 Another embodiment of the present invention includes a step of heat-sealing a thermoplastic resin to the concave side of the heat-bent lens piece.
　また、本発明は、前述のいずれかによる方法で製造された、機能性レンズである。 The present invention also provides a functional lens manufactured by any of the methods described above.
このような機能性レンズを用いた、サングラスまたはゴーグルも本発明の範囲内である。 Sunglasses or goggles using such functional lenses are also within the scope of the present invention.
　本発明によれば、機能性シートに接着層を介してポリアミド樹脂からなるシートを積層してなる機能性シートでは、機能性シート製造後に所定の乾燥環境下にて保管することが好ましいことが明らかとなった。さらに、熱曲げ加工前にはさらに低い水分量となるように乾燥工程を行うことが必要であることがわかった。このように、本発明では、製造工程における機能性シートの水分管理を適切に行うことにより、不良品の発生を少なくすることが可能である。 According to the present invention, it is clear that in a functional sheet obtained by laminating a sheet made of a polyamide resin on a functional sheet with an adhesive layer interposed therebetween, it is preferable to store the functional sheet in a predetermined dry environment after manufacturing the functional sheet. became. Furthermore, it was found that it is necessary to carry out a drying process so that the water content is even lower before hot bending. Thus, in the present invention, it is possible to reduce the occurrence of defective products by appropriately controlling the moisture content of the functional sheet in the manufacturing process.
　以下、本発明の実施形態について説明する。 Embodiments of the present invention will be described below.
　（機能層（偏光フィルム層））
　機能層に用いる偏光フィルムは、基材となる樹脂フィルムを水中で膨潤させた後に、二色性有機染料を含有する染色液に、一方向に延伸させつつ含浸することにより、二色性色素を基材樹脂中に配向した状態で分散させて、偏光性及び所望の色調を付与したフィルムである。 (Functional layer (polarizing film layer))
The polarizing film used for the functional layer is obtained by swelling a resin film as a base material in water and then impregnating it with a dyeing solution containing a dichroic organic dye while stretching it in one direction to obtain a dichroic dye. It is a film imparted with polarizing properties and a desired color tone by being dispersed in a base resin in an oriented state.
　このときに用いる偏光フィルムの基材となる樹脂としては、ポリビニルアルコール類が用いられ、このポリビニルアルコール類としては、ポリビニルアルコール（以下ＰＶＡ）、ＰＶＡの酢酸エステル構造を微量残したもの及びＰＶＡ誘導体または類縁体であるポリビニルホルマール、ポリビニルアセタール、エチレン－酢酸ビニル共重合体ケン化物等が好ましく、特にＰＶＡが好ましい。 Polyvinyl alcohols are used as the base resin of the polarizing film used at this time, and the polyvinyl alcohols include polyvinyl alcohol (hereinafter referred to as PVA), PVA with a small amount of acetate ester structure remaining, and PVA derivatives or Analogues such as polyvinyl formal, polyvinyl acetal, and saponified ethylene-vinyl acetate copolymer are preferred, and PVA is particularly preferred.
　また、ＰＶＡの分子量は、延伸性とフィルム強度の点から重量平均分子量が５０，０００から３５０，０００のものが好ましく、より好ましくは分子量１００，０００から３００，０００、特に、分子量１５０，０００以上が好ましい。ＰＶＡフィルムを延伸する際の倍率は、延伸後の二色比とフィルム強度の点から２～８倍であり、好ましくは３．５～６．５倍、特に４．０～６．０倍が好ましい。延伸後のＰＶＡフィルムの厚みは、１０μｍ以上であり、保護フィルムなどと一体化せずに取り扱いできるとの点から厚み２０μｍ以上で、５０μｍ以下程度が好ましい。 The molecular weight of PVA is preferably a weight average molecular weight of 50,000 to 350,000, more preferably a molecular weight of 100,000 to 300,000, particularly a molecular weight of 150,000 or more, from the viewpoint of stretchability and film strength. is preferred. The stretching ratio for stretching the PVA film is 2 to 8 times, preferably 3.5 to 6.5 times, and particularly 4.0 to 6.0 times in terms of the dichroic ratio and film strength after stretching. preferable. The thickness of the PVA film after stretching is 10 µm or more, and the thickness is preferably 20 µm or more and about 50 µm or less because it can be handled without being integrated with a protective film or the like.
　基材フィルムとしてＰＶＡフィルムを用いる場合の典型的な製造工程は、
（１）ＰＶＡフィルムを水中にて膨潤させつつ水洗し、適宜、不純物を取り除き、
（２）適宜、延伸しつつ、
（３）染色槽にて染色し、
（４）ホウ酸または金属化合物による処理槽にて架橋乃至キレート化処理し、
（５）乾燥する、
との工程にて製造される。尚、工程（２）、（３）（場合により（４））は、適宜、その順序をかえても、また、同時に行っても良いものである。 A typical manufacturing process when using a PVA film as the base film is
(1) The PVA film is swollen in water and washed with water to appropriately remove impurities,
(2) while stretching as appropriate,
(3) Dyeing in a dyeing tank,
(4) cross-linking or chelation treatment in a treatment tank with boric acid or a metal compound;
(5) dry;
Manufactured in the process of The steps (2), (3) (and (4) in some cases) may be changed in order, or may be carried out at the same time.
　まず、工程（１）の膨潤・水洗の工程は、水を吸収させることにより、常温の乾燥状態では容易に破断するＰＶＡフィルムを均一に軟化させて延伸可能とする。また、ＰＶＡフィルムの製造工程に使用される水溶性の可塑剤などを除くこと、或いは、適宜、添加剤を予備的に吸着させる工程である。このときに、ＰＶＡフィルムは順次均一に膨潤するものではなく、必ずバラツキが生じる。この状態でも、局所的に伸ばされ或いは伸び不足のないように、また、皺などの発生を抑えるように可能なかぎり小さい力を均一に負荷するような工夫を行うことが肝要である。また、この工程では、単に均一に膨潤させることが最も望ましいものであり、過剰な延伸などはムラの原因となるので極力しない。 First, in the step (1) of swelling and washing with water, the PVA film, which is easily broken in a dry state at room temperature, is uniformly softened and made stretchable by absorbing water. It is also a step of removing water-soluble plasticizers and the like used in the manufacturing process of the PVA film, or preliminarily adsorbing additives as appropriate. At this time, the PVA film does not gradually and uniformly swell, and variations always occur. Even in this state, it is important to apply a uniform force that is as small as possible so as to prevent local stretching or insufficient stretching and to suppress the occurrence of wrinkles. Moreover, in this step, it is most desirable to simply swell uniformly, and excessive stretching, etc., causes unevenness and should be avoided as much as possible.
　工程（２）は、通常２～８倍となるように延伸を行うものである。
　本発明では、加工性が良いことが重要であるので、延伸倍率を３．５～６．５倍、特に４．０～６．０倍から選択し、この状態でも配向性を維持するのが好ましい。
　延伸配向された状態で、水中に存在する時間、さらに乾燥までの時間が長いと配向緩和が進むものであることから、より高い性能を維持するとの観点からは延伸処理はより短時間となるように設定し、延伸後は、出来るだけ早く水分を除く、すなわち、直ちに乾燥工程に導き過剰な熱負荷を避けつつ乾燥させることが好ましい。 In the step (2), stretching is usually carried out so as to be 2 to 8 times.
In the present invention, good workability is important, so the draw ratio is selected from 3.5 to 6.5 times, particularly 4.0 to 6.0 times, and the orientation is maintained even in this state. preferable.
In the stretched and oriented state, if the time in water and the time until drying are long, the relaxation of the orientation will progress, so from the viewpoint of maintaining higher performance, the stretching process is set to be shorter. However, after stretching, it is preferable to remove moisture as soon as possible, that is, immediately lead to a drying step and dry while avoiding an excessive heat load.
  工程（３）の染色は、配向したポリビニルアルコール系樹脂フィルムのポリマー鎖への染料を吸着或いは沈着させることによる。この機構からは、一軸延伸の前中後のいずれでも可能であり大きな変化はないが、界面という規制の高い表面が最も配向しやすいものであり、これを生かすような条件を選択するのが好ましい。
  温度は、高い生産性との要求から通常は４０～８０℃の高温から選択されるが、本発明では通常２５～４５℃、好ましくは３０～４０℃、特に３０～３５℃から選択する。 Dyeing in step (3) is performed by adsorbing or depositing a dye onto the polymer chains of the oriented polyvinyl alcohol-based resin film. From this mechanism, it is possible before, during, and after uniaxial stretching, and there is no big difference. However, the interface, which is the highly regulated surface, is the most easily oriented, and it is preferable to select conditions that take advantage of this. .
The temperature is usually selected from a high temperature of 40 to 80°C from the requirement of high productivity, but in the present invention it is usually selected from 25 to 45°C, preferably 30 to 40°C, especially 30 to 35°C.
  工程（４）は、耐熱性の向上や耐水性や耐有機溶剤性を向上させるために行う。
  前者のホウ酸による処理はＰＶＡ鎖間の架橋にて耐熱性を向上させるものであるが、ポリビニルアルコール系樹脂フィルムの一軸延伸の前中後のいずれでも可能であり大きな変化はない。また、後者の金属化合物は主に、染料分子とキレート化合物を形成して安定化させるものであり、通常、染色後或いは染色と同時に行う。
  金属化合物としては、第４周期、第５周期、第６周期のいずれの周期に属する遷移金属であっても、その金属化合物に前記耐熱性および耐溶剤性効果の確認されるものが存在するが、価格面からクロム、マンガン、コバルト、ニッケル、銅、亜鉛などの第４周期遷移金属の酢酸塩、硝酸塩、硫酸塩などの金属塩が好ましい。これらの中でも、ニッケル、マンガン、コバルト、亜鉛および銅の化合物が、安価で前記効果に優れるため、さらに好ましい。 Step (4) is performed to improve heat resistance, water resistance, and organic solvent resistance.
The former treatment with boric acid improves the heat resistance by cross-linking between PVA chains. In addition, the latter metal compound mainly forms a chelate compound with dye molecules to stabilize them, and is usually carried out after dyeing or at the same time as dyeing.
As the metal compound, there are transition metals belonging to any of the 4th, 5th, and 6th periods that are confirmed to have the heat resistance and solvent resistance effects described above. Metal salts such as acetates, nitrates and sulfates of 4th period transition metals such as chromium, manganese, cobalt, nickel, copper and zinc are preferred from the viewpoint of cost. Among these, compounds of nickel, manganese, cobalt, zinc and copper are more preferable because they are inexpensive and excellent in the above effects.
  金属化合物およびホウ酸の前記偏光フィルム中の含有率は、前記偏光フィルムに耐熱性および耐溶剤性を与える点から、偏光フィルム１ｇ当たり、金属化合物では金属として０．２～２０ｍｇ含有されることが好ましく、１～５ｍｇが更に好ましい。ホウ酸の含有率は、ホウ素として０．３～３０ｍｇが好ましく、０．５～１０ｍｇが更に好ましい。
  処理に用いる処理液の組成は以上の含有率を満たすように設定され、一般的には、金属化合物の濃度は０．５～３０ｇ／Ｌ、ホウ酸濃度は２～２０ｇ／Ｌであることが好ましい。
  偏光フィルムに含有される金属およびホウ素の含有率の分析は、原子吸光分析法により行うことができる。 From the viewpoint of imparting heat resistance and solvent resistance to the polarizing film, the content of the metal compound and boric acid in the polarizing film is 0.2 to 20 mg of the metal compound per 1 g of the polarizing film. Preferably, 1 to 5 mg is more preferable. The boric acid content is preferably 0.3 to 30 mg, more preferably 0.5 to 10 mg as boron.
The composition of the treatment liquid used for the treatment is set so as to satisfy the above contents, and generally the concentration of the metal compound is 0.5 to 30 g/L and the concentration of boric acid is 2 to 20 g/L. preferable.
The content of metal and boron contained in the polarizing film can be analyzed by atomic absorption spectrometry.
  温度は、通常、染色と同じ条件を採用するが、通常、２０～７０℃、好ましくは２５～４５℃、より好ましくは３０～４０℃、特に３０～３５℃から選択する。また、時間は、通常、０.５～１５分から選択する。 The temperature is usually the same as for dyeing, but is usually selected from 20 to 70°C, preferably 25 to 45°C, more preferably 30 to 40°C, especially 30 to 35°C. Also, the time is usually selected from 0.5 to 15 minutes.
  工程（５）にて、延伸、染色及び適宜、ホウ酸または金属化合物にて処理された染色一軸延伸ＰＶＡフィルムを乾燥する。ＰＶＡフィルムは、含有する水分量に相当する耐熱性を示すものであり、水を多量に含む状態で温度が高くなってくると、より短時間で、一軸延伸状態からの乱れなどが生じ、二色比の低下が起こる。
  乾燥は表面から進むものであり、両表面から乾燥させることが好ましく、乾燥空気送風にて水蒸気を除きつつ行うことが好ましい。また、周知のように、過剰な加熱を避ける点から、蒸発した水分を直ちに除去して蒸発を促進させる方法が温度上昇を抑えた乾燥ができる点から好ましく、乾燥空気の温度を乾燥状態の偏光フィルムが実質的に変色しない温度以下の範囲から、通常、７０℃以上、好ましくは９０～１２０℃の温度で、１～１２０分間、好ましくは３～４０分間にて送風乾燥する。
  乾燥後のＰＶＡ含水率は、通常１～４ｗｔ％の含水率となるように製造される。 In step (5), the stretched, dyed and optionally dyed uniaxially stretched PVA film treated with boric acid or metal compound is dried. A PVA film exhibits heat resistance corresponding to the amount of water it contains. A loss of color ratio occurs.
Drying proceeds from the surface, and it is preferable to dry from both surfaces, preferably while removing water vapor by blowing dry air. In addition, as is well known, from the point of avoiding excessive heating, the method of immediately removing the evaporated moisture to promote evaporation is preferable from the point that drying can be performed while suppressing the temperature rise. Air drying is carried out at a temperature of 70° C. or higher, preferably 90° C. to 120° C., for 1 to 120 minutes, preferably 3 to 40 minutes, from the temperature range below which the film does not substantially discolor.
The moisture content of PVA after drying is usually 1 to 4 wt%.
（機能層（調光層））
  本発明の機能層としては、ウレタン系フィルムに調光色素が練りこまれた調光フィルムなども好適に用いることができる。また、後述する接着層に調光色素を練りこんでもよく、例えば、以下の方法により、フォトクロミック化合物を含有する熱硬化性ポリウレタン樹脂層からなる調光層を製造できる。尚、調光色素（フォトクロミック化合物）としては、ポリウレタンプレポリマーとの相溶性が良ければ特に制限されず、市販の有機フォトクロミック化合物が使用できる。フォトクロミック性能から、スピロピラン系化合物、スピロオキサジン系化合物およびナフトピラン系化合物が好ましく使用される。 (Functional layer (light control layer))
As the functional layer of the present invention, a light control film in which a light control dye is kneaded into a urethane film can be suitably used. Further, a photochromic dye may be kneaded into the adhesive layer, which will be described later. For example, a photochromic compound-containing thermosetting polyurethane resin layer can be produced by the following method. The photochromic dye (photochromic compound) is not particularly limited as long as it is compatible with the polyurethane prepolymer, and commercially available organic photochromic compounds can be used. Spiropyran-based compounds, spirooxazine-based compounds and naphthopyran-based compounds are preferably used in terms of photochromic performance.
  調光層に用いる調光フィルムの製造法を例示する。ポリウレタンプレポリマーを特定有機溶媒で希釈した溶液に、フォトクロミック化合物を樹脂固形分に対して０．２～５重量％の割合で加え、さらに樹脂固形分に対して０．１～５重量％のヒンダードアミン系の光安定剤及び／又は酸化防止剤等の添加剤を加え、均一に攪拌混合する。その後、更にイソシアネート基（Ｉ）と硬化剤の水酸基（Ｈ）の比Ｉ／Ｈが０．９～２０、好ましくは１～１０を目安として硬化剤を加えさらに攪拌し、溶液を形成させる。溶液中のポリマー濃度は、一般的には４０～９０重量％が適当である。該溶液を表面に塗膜層を設けた透明なポリカーボネートシートの裏面に塗布厚５０～１０００μｍのドクターブレードを使用して塗布する。塗布後、塗布面が溶媒を実質的に含まない状態まで加熱乾燥し、該合成樹脂シートの塗布面に他の表面に塗膜層を設けた透明なポリカーボネートシートの裏面を貼り合わせ、サンドイッチ状として、更に放置乾燥して調光フィルムを得る。 A method for manufacturing a light control film used for the light control layer is exemplified. A photochromic compound is added to a solution obtained by diluting a polyurethane prepolymer with a specific organic solvent in a proportion of 0.2 to 5% by weight relative to the resin solid content, and a hindered amine is added in an amount of 0.1 to 5% by weight relative to the resin solid content. Additives such as light stabilizers and/or antioxidants for the system are added and uniformly stirred and mixed. After that, a curing agent is further added so that the ratio I/H of the isocyanate group (I) to the hydroxyl group (H) of the curing agent is 0.9 to 20, preferably 1 to 10, and the mixture is further stirred to form a solution. A suitable polymer concentration in the solution is generally 40 to 90% by weight. The solution is applied to the back surface of a transparent polycarbonate sheet having a coating layer on its surface using a doctor blade with a coating thickness of 50 to 1000 μm. After coating, the coated surface is dried by heating until it does not substantially contain a solvent, and the coated surface of the synthetic resin sheet is laminated with the back surface of a transparent polycarbonate sheet provided with a coating layer on the other surface to form a sandwich. and then left to dry to obtain a light control film.
（接着層）
  機能層と保護層とを積層して機能性シートとするために機能層と保護層との間に接着層を介在させる。通常、機能性シートに用いられる接着剤の材料としては、ポリビニルアルコール樹脂系材料、アクリル樹脂系材料、ウレタン樹脂系材料、ポリエステル樹脂系材料、メラミン樹脂系材料、エポキシ樹脂系材料、シリコーン系材料等がある。
  本願においては、熱曲げ加工、射出成型工程での安定性を考慮した場合、熱硬化性材料が好ましく、特にウレタン樹脂系材料であるポリウレタンプレポリマーと硬化剤からなる２液型の熱硬化性ウレタン樹脂が好ましい。 (adhesion layer)
In order to laminate the functional layer and the protective layer to form a functional sheet, an adhesive layer is interposed between the functional layer and the protective layer. Adhesive materials usually used for functional sheets include polyvinyl alcohol resin-based materials, acrylic resin-based materials, urethane resin-based materials, polyester resin-based materials, melamine resin-based materials, epoxy resin-based materials, and silicone-based materials. There is
In the present application, a thermosetting material is preferable from the viewpoint of stability in thermal bending and injection molding processes, and in particular, a two-liquid type thermosetting urethane consisting of a polyurethane prepolymer, which is a urethane resin material, and a curing agent. Resins are preferred.
  ポリウレタンプレポリマーとしては、ジイソシアネート化合物とポリオキシアルキレンジオールとを一定割合で反応させた化合物であって、両末端にイソシアネート基を有する化合物である。ポリウレタンプレポリマーに使用されるジイソシアネート化合物としては、ジフェニールメタン－４，４’－ジイソシアネート、トリ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、イソホロンジイソシアネート、４，４’－ジシクロヘキシルメタンジイソシアネート、リジンイソシアネート、水添キシリレンジイソシアネートが使用できるが、ジフェニールメタン－４，４’－ジイソシアネートが好ましい。ポリオキシアルキレンジオールとしては、ポリプロピレングリコール、ポリエチレングリコール、ポリオキシテトラメチレングリコールが使用できるが、５～３０の重合度を有するポリプロピレングリコールを使用することが好ましい。ポリウレタンプレポリマーの分子量は、特に限定されないが通常数平均分子量５００～５０００のものであり、好ましくは１５００～４０００、より好ましくは２０００～３０００である。 The polyurethane prepolymer is a compound obtained by reacting a diisocyanate compound and a polyoxyalkylenediol at a constant ratio and having isocyanate groups at both ends. Diisocyanate compounds used in polyurethane prepolymers include diphenylmethane-4,4′-diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, lysine isocyanate, and hydrogenated xylylene diisocyanate. Isocyanates can be used, but diphenylmethane-4,4'-diisocyanate is preferred. Polypropylene glycol, polyethylene glycol, and polyoxytetramethylene glycol can be used as the polyoxyalkylene diol, and it is preferable to use polypropylene glycol having a degree of polymerization of 5-30. Although the molecular weight of the polyurethane prepolymer is not particularly limited, it usually has a number average molecular weight of 500 to 5,000, preferably 1,500 to 4,000, and more preferably 2,000 to 3,000.
  一方、硬化剤としては、水酸基を２個以上有する化合物であれば特に限定されるものではなく、ポリウレタンポリオール、ポリエーテルポリオール、ポリエステルポリオール、アクリルポリオール、ポリブタジエンポリオール、ポリカーボネートポリオール等が例示され、その中でも特定のイソシアネートと特定のポリオールから得られる末端に水酸基を有するポリウレタンポリオールが好ましい。特にジイソシアネート化合物とポリオールから誘導される少なくとも両末端に水酸基を有するポリウレタンポリオールが好ましい。該ジイソシアネート化合物としては、ジフェニールメタン－４，４’－ジイソシアネート、トリ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、イソホロンジイソシアネート、４，４’－ジシクロヘキシルメタンジイソシアネート、リジンイソシアネート、水添キシリレンジイソシアネートが使用できるが、トリレンジイソシアネートを使用することが好ましい。また、ポリオールとしては、トリメチロールプロパン等をエチレンオキサイド或いはプロピレンオキサイドと反応させたものが使用でき、重合度が５～３０のポリプロピレングリコール誘導体を使用することが好ましい。この硬化剤の分子量は特に限定されないが通常数平均分子量５００～５０００であり、好ましくは１５００～４０００、より好ましくは２０００～３０００である。 On the other hand, the curing agent is not particularly limited as long as it is a compound having two or more hydroxyl groups. Polyurethane polyols having terminal hydroxyl groups obtained from specific isocyanates and specific polyols are preferred. Particularly preferred is a polyurethane polyol derived from a diisocyanate compound and a polyol and having hydroxyl groups at least at both ends. Diphenylmethane-4,4'-diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, lysine isocyanate, and hydrogenated xylylene diisocyanate can be used as the diisocyanate compound. Preference is given to using tolylene diisocyanate. As the polyol, a product obtained by reacting trimethylolpropane or the like with ethylene oxide or propylene oxide can be used, and it is preferable to use a polypropylene glycol derivative having a degree of polymerization of 5 to 30. Although the molecular weight of this curing agent is not particularly limited, the number average molecular weight is usually 500-5000, preferably 1500-4000, more preferably 2000-3000.
  これらのポリウレタンプレポリマー及び硬化剤は粘度調節のために酢酸エチル及びテトラヒドロフランなどの溶媒を使用することができる。また、接着層に調光機能を付与する場合において、溶媒の使用はフォトクロミック化合物をウレタン樹脂中に均一に分散させるために有効な方法である。 These polyurethane prepolymers and curing agents can use solvents such as ethyl acetate and tetrahydrofuran for viscosity control. In the case of imparting a light control function to the adhesive layer, the use of a solvent is an effective method for uniformly dispersing the photochromic compound in the urethane resin.
（保護層）
  本発明の個別レンズ用片に用いる機能性シートには、少なくともその片面にポリアミド樹脂からなる保護層（又は保護フィルム又は偏光膜用保護フィルム）が形成されている。
  前記ポリアミド樹脂は、透明性や成形加工性の観点から非晶性ポリアミド或いは微結晶性ポリアミドと称されるものが望ましく、後述する射出成形加工ができるものが好ましい。すなわち、熱可塑性で、熱分解温度以下で成形可能な溶融流動性を示すものであり、適度のＴｇ（ガラス転移温度）を有するものであれば、好適に用いることができる。
  非晶性を条件とした場合、結晶性となる繰り返し単位の量に制限が生じ、結晶性を阻害する分子構造の例として立体障害性を付与する構造が挙げられ、分岐構造や置換基の導入、シクロアルカンのような嵩高い分子構造が用いられる。
  適度の耐熱性との条件においては、繰り返し単位中（単位分子鎖長）にエンタルピーの大きい構造や、繰り返し単位内及び繰り返し単位相互間の分子運動を制限する構造が必須となり、前者の典型例が芳香族であり、後者の例が合成物では芳香核の不飽和結合を水素添加した構造のシクロアルカン、シクロアルケンなどが用いられる。また、脂環構造を持つものは、上記したように、耐熱性と結晶性を阻害する分子構造とを有することから、熱曲げ加工等に供するポリアミドを保護層としたサングラス用の機能性シートとするために有用な材料といえる。
  ポリアミドは一般的にジアミン、ジカルボン酸、アミノカルボン酸等のモノマーに由来する構成単位を有する。芳香族ポリアミドや脂環族ポリアミドは、原理的には、全脂肪族ポリアミドを構成する少なくとも一種のモノマーに由来する構成単位を芳香族または脂環族とすることにより製造される。これらモノマーの全部または一部を芳香族または脂環族として、部分芳香族ポリアミド、芳香族部分脂環族ポリアミド、部分芳香族部分脂環族ポリアミド、部分芳香族脂環族ポリアミド、部分脂環族ポリアミドなど、或いはそれらの組み合わせが本願発明に使用可能であるが、非晶性と適度な耐熱性とを有する非晶性ポリアミドの典型例の一つとして、脂環構造を持つポリアミドを好適に用いることができる。尚、後述するリタデーションなどの光学特性を考慮した場合には、芳香族部分を含むことが望ましい。
  当然に、ポリアミドの酸化劣化、加工不具合への対処などのために、本発明に使用するポリアミド樹脂には適宜、滑剤、酸化防止剤などの添加剤が用いられる。 (protective layer)
The functional sheet used for the individual lens pieces of the present invention has a protective layer (or a protective film or a protective film for polarizing film) made of a polyamide resin formed on at least one surface thereof.
The polyamide resin is preferably amorphous polyamide or microcrystalline polyamide from the viewpoint of transparency and molding processability, and preferably can be injection molded as described later. That is, any material can be suitably used as long as it is thermoplastic, exhibits moldable melt fluidity at a temperature below the thermal decomposition temperature, and has an appropriate Tg (glass transition temperature).
When amorphousness is a condition, the amount of crystalline repeating units is limited, and examples of molecular structures that inhibit crystallinity include structures that impart steric hindrance, branched structures, and the introduction of substituents. , cycloalkanes are used.
In terms of moderate heat resistance, a structure with a large enthalpy in the repeating unit (unit molecular chain length) and a structure that restricts molecular movement within the repeating unit and between repeating units are essential, and a typical example of the former is It is aromatic, and in the latter example, cycloalkane, cycloalkene, etc. having a structure obtained by hydrogenating the unsaturated bond of the aromatic nucleus are used. In addition, since those having an alicyclic structure have a molecular structure that inhibits heat resistance and crystallinity as described above, a functional sheet for sunglasses having a protective layer made of a polyamide that is subjected to thermal bending etc. It can be said that it is a useful material for
Polyamides generally have structural units derived from monomers such as diamines, dicarboxylic acids and aminocarboxylic acids. Aromatic polyamides and alicyclic polyamides are, in principle, produced by making aromatic or alicyclic constitutional units derived from at least one type of monomer constituting the wholly aliphatic polyamide. Partially aromatic polyamide, partially aromatic alicyclic polyamide, partially aromatic alicyclic polyamide, partially aromatic alicyclic polyamide, partially alicyclic Polyamides and the like, or combinations thereof, can be used in the present invention, but as one typical example of amorphous polyamides having amorphous properties and moderate heat resistance, polyamides having an alicyclic structure are preferably used. be able to. In consideration of optical properties such as retardation, which will be described later, it is desirable to include an aromatic moiety.
Naturally, additives such as lubricants and antioxidants are appropriately used in the polyamide resin used in the present invention in order to deal with oxidative deterioration of polyamide, processing defects, and the like.
  本発明の機能性シートを個別レンズ用片とするために打抜き加工を施し、これを熱曲げ加工し、必要に応じてその凹面側に熱可塑性樹脂を射出融着にて一体化してポリアミド機能性レンズとすると、光学歪が生じることがある。すなわちそれを斜めから見ると虹色の「色むら」が観測されたり、又は、該曲面偏光板を互いの偏光軸が直交位となるように配置した平面偏光板と重ねて観察すると、光が透過する、いわゆる「偏光漏れ」が観察されたりする。これらは、保護層に用いる樹脂の複屈折が大きい、すなわち固有複屈折率、或いは光弾性係数が大きいため、溶融押し出し成型時や前記熱曲げ加工時の応力によって、リタデーション値（定義：複屈折△ｎ×厚さｄ）が大きくなり（例えば、３００ｎｍ～１２００ｎｍなど）、内層に設けられた偏光フィルム層の偏光を乱して、加工後にレンズの凹面になる面において上記した「偏光漏れ」などの不具合が観察される。また、凸面では、斜めから観察すると「色むら」として着色干渉縞が観察される。 In order to make the functional sheet of the present invention into pieces for individual lenses, punching is performed, this is subjected to thermal bending, and if necessary, a thermoplastic resin is integrated on the concave side by injection fusion to form a polyamide functional sheet. When used as a lens, optical distortion may occur. That is, when viewed obliquely, iridescent "color unevenness" is observed, or when the curved polarizing plate is superimposed on a plane polarizing plate arranged so that the polarization axes are orthogonal to each other, the light is A so-called "polarization leakage" that is transmitted may be observed. Since the resin used for the protective layer has a large birefringence, that is, a large intrinsic birefringence or photoelastic coefficient, the retardation value (definition: birefringence △ n × thickness d) increases (for example, 300 nm to 1200 nm), disturbs the polarization of the polarizing film layer provided in the inner layer, and causes the above-described "polarization leakage" on the surface that becomes the concave surface of the lens after processing. A defect is observed. Also, on the convex surface, colored interference fringes are observed as "color unevenness" when obliquely observed.
  以上から、保護層は内層に設けられた偏光フィルム層の機能を阻害しない程度のリタデーション値（例えば、３００ｎｍ以下、好ましくは２００ｎｍ以下、より好ましくは１００ｎｍ以下）である保護層を、少なくともレンズ加工後に凸面となる位置に配置することが望ましい。
  このような低いリタデーションとする場合、その保護層の厚みは、１００μｍ以下、好ましくは８０μｍ以下の厚みとすることが望ましい。また、より分子配向を促しにくいキャスト法などにより製造されたフィルムを保護層として好適に用いることができるが、キャスト製法においても、引き取り時に不要な応力が発生してリタデーション値が大きくなることの無いように注意が必要である。
  また、上記したキャストフィルムのような、厚み１００μｍ以下でリタデーションが上記した小さな値となるように製造する場合、ポリアミド樹脂は芳香族成分を含まないほうが固有複屈折値は小さく保ちやすく、後述する熱曲げ加工などにおいてもリタデーション値の増加を抑制しやすい。 From the above, the protective layer has a retardation value (for example, 300 nm or less, preferably 200 nm or less, more preferably 100 nm or less) that does not hinder the function of the polarizing film layer provided in the inner layer. It is desirable to arrange it in a convex position.
For such low retardation, the thickness of the protective layer is desirably 100 μm or less, preferably 80 μm or less. In addition, a film manufactured by a casting method or the like, which is less likely to promote molecular orientation, can be suitably used as a protective layer. Care must be taken to
In the case of producing a cast film having a thickness of 100 μm or less and a small retardation value as described above, it is easier to keep the intrinsic birefringence value small when the polyamide resin does not contain an aromatic component. It is easy to suppress an increase in the retardation value even in bending.
  或いは、リタデーション値を小さく保つ以外の方法では、逆にリタデーション値を極端に大きく、例えば、１３００ｎｍ以上、好ましくは２０００ｎｍ以上、より好ましくは３０００ｎｍ以上とした保護層をレンズに加工した後の凸面に配置されるようにして、「色ムラ」や「偏光漏れ」という現象を、肉眼では問題とならない程度に分かり難くすることにより対処できる。
  このようにリタデーション値を極端に高くする場合には、ポリアミド樹脂からなる保護層を延伸処理する必要がある。その場合、溶融押し出し法などによりある程度の厚み、例えば１００μｍ以上、好ましくは１５０μｍ以上、より好ましくは２００μｍ以上、更に好ましくは３００μｍ以上の厚みに成型したシートを延伸し、所望のリタデーション値と厚みを有する保護フィルムにするなどの方法が望ましい。なお、本願発明においてリタデーション値は面内リタデーション値である。面内リタデーション値は入射直線偏光を遅相軸及び進相軸に分解したときに、遅相軸方向の屈折率、進相軸方向の屈折率、およびフィルムの厚みから導きだせることは当業者の知識の範囲内である。なお、本開示において、リタデーション値は５９０ｎｍにて測定した値である。測定装置としては、大塚電子製リタデーション測定装置：ＲＥＴＳ－１００などがある。 Alternatively, in a method other than keeping the retardation value small, a protective layer with an extremely large retardation value, for example, 1300 nm or more, preferably 2000 nm or more, more preferably 3000 nm or more, is arranged on the convex surface after processing into a lens. In this way, the phenomena of "color unevenness" and "polarization leakage" can be dealt with by making them indistinguishable to the naked eye.
In order to increase the retardation value extremely like this, it is necessary to stretch the protective layer made of the polyamide resin. In that case, a sheet molded to a certain thickness, for example, 100 μm or more, preferably 150 μm or more, more preferably 200 μm or more, and still more preferably 300 μm or more, is stretched by a melt extrusion method or the like to obtain a desired retardation value and thickness. A method such as using a protective film is desirable. In the present invention, the retardation value is an in-plane retardation value. Those skilled in the art know that the in-plane retardation value can be derived from the refractive index in the slow axis direction, the refractive index in the fast axis direction, and the thickness of the film when the incident linearly polarized light is resolved into the slow axis and the fast axis. It is within my knowledge. In addition, in this disclosure, the retardation value is a value measured at 590 nm. As a measuring device, there is a retardation measuring device: RETS-100 manufactured by Otsuka Electronics.
  溶融押し出し法で成型したフィルムを延伸してリタデーション値を高めるには、引き取る際に延伸しながら引き取るドロー延伸法や、成型後に一度巻取り、別途延伸を行うオフライン延伸法などが挙げられる。
  溶融押出成形法では、例えば、前記ポリアミド樹脂又は保護層を構成する樹脂を押出機などで溶融混合し、ダイ（例えば、Ｔダイなど）から押出成形し、冷却することによりポリアミドシートを製造できる。前記ポリアミド樹脂又は保護層を構成する樹脂を溶融して成形する（溶融成形する）際の樹脂温度は、通常、１２０℃～３５０℃程度の温度範囲から選択でき、例えば、１３０～３００℃、好ましくは１５０～２８０℃、さらに好ましくは１６０～２５０℃程度である。この際、冷却ロールの速度よりも引き取る速度を速めることにより延伸処理を行うことができる。 Examples of stretching a film molded by a melt extrusion method to increase the retardation value include a draw-stretching method in which the film is pulled out while being stretched, and an off-line stretching method in which the film is wound once after molding and then stretched separately.
In the melt extrusion method, for example, a polyamide sheet can be produced by melt-mixing the polyamide resin or the resin constituting the protective layer with an extruder or the like, extruding the mixture from a die (eg, a T-die), and cooling. The resin temperature when the polyamide resin or the resin constituting the protective layer is melted and molded (melt molding) can usually be selected from a temperature range of about 120 ° C. to 350 ° C., for example, 130 to 300 ° C., preferably is about 150 to 280°C, more preferably about 160 to 250°C. At this time, the drawing process can be performed by making the take-up speed faster than the speed of the cooling rolls.
  本発明の機能性シートの性能を阻害することがなければ、延伸の具体的方法は特に限定されるものではない。延伸部分のロールは、延伸ムラを抑制するために、適宜金型温調器などでロールを加温しつつ樹脂温を一定に保つことが好ましい。一般には、ポリアミド樹脂のＴｇ付近においてサングラス用のシートとして好適な外観性を維持した延伸が可能となる。樹脂温度が、使用するポリアミド樹脂のＴｇに対して低い温度帯で延伸する場合には、均一に延伸されない延伸ムラを招きやすく、延伸された箇所と延伸されていない箇所のムラ模様が生じる。また、Ｔｇに対して高い温度帯で延伸する場合には、ポリアミドフィルム、或いはシートのロールへの溶着を招くため、ロールからフィルム、或いはシートが引き剥がされる際の跡が残るなどの問題を招く。適宜、後述するリタデーションとの関係も考慮しつつ、ロールやその他温調機の条件を選択する必要がある。
  尚、本願発明でいうＴｇとは、ＤＳＣで測定した場合のＴｇ曲線における始点、中間点、終点温度の内、中間点温度を示唆している。 The specific stretching method is not particularly limited as long as it does not impair the performance of the functional sheet of the present invention. In order to suppress uneven stretching, it is preferable that the resin temperature of the rolls in the stretching portion is kept constant while the rolls are appropriately heated by a mold temperature controller or the like. In general, it is possible to stretch the sheet around the Tg of the polyamide resin while maintaining an appearance suitable for a sheet for sunglasses. When stretching is performed in a temperature range in which the resin temperature is lower than the Tg of the polyamide resin to be used, uneven stretching is likely to occur, resulting in an uneven pattern between stretched and non-stretched portions. In addition, when stretching in a temperature range higher than Tg, the polyamide film or sheet is welded to the roll, which causes problems such as leaving traces when the film or sheet is peeled off from the roll. . It is necessary to appropriately select the conditions of the rolls and other temperature controllers while also considering the relationship with retardation, which will be described later.
Incidentally, the Tg referred to in the present invention indicates the temperature at the middle point among the temperatures at the start point, the middle point, and the end point in the Tg curve measured by DSC.
  また、延伸時における保護層シートの樹脂温度は、リタデーションの付与にも関係する。延伸時のフィルム、或いはシートの樹脂温度が、使用している樹脂のＴｇに対して低い温度帯で延伸処理を行うならば、より高いリタデーションを付与しやすく、また高い温度となるほどにリタデーションは発現しにくいものとなる。更に、延伸後は、可能な限りすばやく冷却することが好ましく、それによりリタデーション及び、遅走軸と進走軸の角度を固定することができる。
  また、Ｔｇに対して低い温度帯で延伸した場合には、シート成型後に収縮などの問題に影響する場合があるので、その点を考慮して延伸温度条件を選択することが必須である。逆に、Ｔｇに対して高い樹脂温度で延伸した場合には、延伸中にシートのネックインの影響が大きくなって厚み分布に影響し、リタデーションや進相軸角度のバラツキを大きくさせる場合があるので、延伸倍率を上げすぎないなどの注意が必要となる。 In addition, the resin temperature of the protective layer sheet during stretching is also related to imparting of retardation. If the resin temperature of the film or sheet during stretching is lower than the Tg of the resin being used, it is easier to impart higher retardation if the stretching process is performed. It becomes difficult. Furthermore, it is preferable to cool the film as quickly as possible after stretching so that the retardation and the angle between the slow and fast axes can be fixed.
Moreover, when the sheet is stretched in a temperature range lower than the Tg, problems such as shrinkage may occur after sheet molding, so it is essential to select the stretching temperature conditions in consideration of this point. Conversely, when stretching is performed at a resin temperature higher than Tg, the influence of neck-in of the sheet increases during stretching, affecting the thickness distribution, and retardation and the fast axis angle may increase. Therefore, it is necessary to be careful not to increase the draw ratio too much.
  溶融押し出し法で成型されたポリアミド樹脂を延伸して保護層とする場合には、芳香族成分の含まれたポリアミド樹脂を使用することは望ましい。これにより、樹脂としての固有複屈折値が高くなり、より低い応力にてリタデーションを高く発現させやすく、また、Ｔｇより高い樹脂温で延伸してもリタデーションを維持しやすくなる。
  上記したとおりポリアミド樹脂の組成により固有複屈折値は異なり、また所望するリタデーション値にもよる為、延伸処理における延伸倍率については適宜調整が必須となる。尚、一般的には、最低でも１．１倍、好ましくは１．２倍、より好ましくは１．３倍以上が必要となる。倍率が高まるほどにネックインが促進され、或いは破断のリスクが生じるなどの理由から生産効率の観点でその上限が決まる。通常には２．２倍程度、好ましくは２．０倍以下程度である。 When a polyamide resin molded by a melt extrusion method is stretched to form a protective layer, it is desirable to use a polyamide resin containing an aromatic component. As a result, the inherent birefringence value of the resin becomes high, it is easy to develop high retardation with lower stress, and it becomes easy to maintain the retardation even when the resin is stretched at a temperature higher than Tg.
As described above, the intrinsic birefringence value varies depending on the composition of the polyamide resin, and it also depends on the desired retardation value, so it is essential to appropriately adjust the draw ratio in the drawing process. In general, at least 1.1 times, preferably 1.2 times, more preferably 1.3 times or more is required. The higher the magnification, the more neck-in is promoted, or the risk of breakage occurs, so the upper limit is determined from the viewpoint of production efficiency. It is usually about 2.2 times, preferably about 2.0 times or less.
  これまでサングラス用偏光シートの保護層として一般に用いられてきた芳香族ポリカーボネート樹脂と比較して、ポリアミド樹脂は吸湿性が高いことが知られていた。当然に、ポリアミド樹脂を溶融押し出しして製造されたポリアミド樹脂保護層も吸湿性が高くなる。前述のように、光学機能層は水分の影響を受けることは芳香族ポリカーボネート樹脂を保護層とする場合も同様であり、このことを考慮すれば、ポリアミド樹脂を保護層とする場合にも、熱曲げ加工の前に十分な乾燥を行うことで対応可能であると考えられる。しかしながら、後述するように、本願発明においては熱曲げ加工の前のみに乾燥を十分に行った場合であっても、不十分であり、積層体とした後にも所定の乾燥状態を維持することが必要であった。
　結晶化度の高いポリアミド樹脂は一般的に形態安定性も高く、故に、吸湿性も低い。本願発明においては、後述するように、透明性、加工性、さらにガスバリア性の観点から、非晶性或いは微結晶性ポリアミド樹脂を用いることが好ましい。
　ポリアミド樹脂の構造として規則性が高いもの、例えば、テレフタル酸（１，４－ジカルビキシベンゼン）や１，４－ジアミノベンゼンをモノマーとするものを含むポリアミドなどは、その結合は平板状で同一平面上配置を持ち、規則性が高く気体透過の小さい集合体を作りやすくなるので、ガスバリア性が高くなる傾向にある。この点も考慮して、ポリアミド樹脂シートの組成を選択しなければならない。
  また、当然に、保護層の厚みや延伸処理の条件により、保護層のガスバリア性も大きく影響を受ける。未延伸の状態において気泡が発生しない程度のガスバリア性を備える保護層であっても、その延伸倍率が高くなるほどに分子配向が促され、そのような状態で冷却、固定されてなる保護層では気泡が発生するようなガスバリア性を示す場合がある。
尚、ガスバリア性については、酸素透過度の評価法は、ＤＩＳ／ＩＳＯ  １５１０５－１に準拠して測定することができる。 Polyamide resins are known to have higher hygroscopicity than aromatic polycarbonate resins, which have been generally used as protective layers for polarizing sheets for sunglasses. Naturally, the polyamide resin protective layer produced by melt-extrusion of the polyamide resin also has high hygroscopicity. As mentioned above, the fact that the optical function layer is affected by moisture is the same when the aromatic polycarbonate resin is used as the protective layer. It is thought that it can be handled by performing sufficient drying before bending. However, as will be described later, in the present invention, even if the drying is sufficiently performed only before the heat bending process, it is insufficient, and it is impossible to maintain a predetermined dry state even after forming the laminate. was necessary.
A polyamide resin with a high degree of crystallinity generally has high shape stability and therefore low hygroscopicity. In the present invention, as will be described later, it is preferable to use an amorphous or microcrystalline polyamide resin from the viewpoint of transparency, workability, and gas barrier properties.
Polyamide resins with a highly regular structure, such as polyamides containing terephthalic acid (1,4-dicarboxybenzene) and 1,4-diaminobenzene as monomers, have flat and identical bonds. Since it is arranged on a plane, it is easy to form aggregates with high regularity and low gas permeability, so gas barrier properties tend to be high. The composition of the polyamide resin sheet must be selected taking this point into consideration.
Naturally, the gas barrier properties of the protective layer are greatly affected by the thickness of the protective layer and the stretching conditions. Even if the protective layer has a gas barrier property that does not generate air bubbles in an unstretched state, the higher the draw ratio, the more the molecular orientation is promoted. may exhibit gas barrier properties that generate
As for the gas barrier property, the oxygen permeability can be measured according to DIS/ISO 15105-1.
  保護層の厚みや延伸の程度については、最終製品の仕様と酸素透過度とを考慮して決定することができる。
  本願においては、保護層の酸素透過度が２３℃、８５％ＲＨにて、１０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ程度となる場合は気泡の発生が顕著となり機能性シートとしての使用に耐えない。
  気泡の発生を抑制する場合には、保護層の酸素透過度が、５０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、６０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、７０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、９０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、１１０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、１３０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、１５０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上である事が望ましい。或いは、４００ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、４１０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、４２０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上、４３０ｃｍ３／ｍ２・２４ｈｒ・ｂａｒ以上であってもよい。なお、本願発明の趣旨より、良好なレンズ成形が可能な保護層である限り、保護層の酸素透過度の上限値は特に重要ではない。樹脂組成及び、保護層厚みや延伸処理などの条件は、この点を考慮して組み合わせを選択する必要がある。 The thickness and degree of stretching of the protective layer can be determined in consideration of the specifications and oxygen permeability of the final product.
In the present application, when the oxygen permeability of the protective layer is about 10 cm 3 /m 2 ·24 hr·bar at 23°C and 85% RH, the generation of air bubbles is significant and the functional sheet cannot be used.
When suppressing the generation of air bubbles, the oxygen permeability of the protective layer is 50 cm 3 /m 2 ·24 hr·bar or more, 60 cm 3 /m 2 ·24 hr·bar or more, 70 cm 3 /m 2 ·24 hr·bar or more. , 90 cm 3 /m 2 ·24 hr·bar or more, 110 cm 3 /m 2 ·24 hr·bar or more, 130 cm 3 /m 2 ·24 hr·bar or more, 150 cm 3 /m 2 ·24 hr·bar or more. Alternatively, it may be 400 cm 3 /m 2 .24 hr.bar or more, 410 cm 3 /m 2 .24 hr.bar or more, 420 cm 3 /m 2 .24 hr.bar or more, or 430 cm 3 /m 2 .24 hr.bar or more. . From the gist of the present invention, the upper limit of the oxygen permeability of the protective layer is not particularly important as long as the protective layer allows good lens molding. It is necessary to select a combination of conditions such as the resin composition, the thickness of the protective layer, and the stretching treatment, taking this point into consideration.
  本願発明においては、機能性シートの含水率を基準にとして発明の効果を判断しているが、本願発明の効果は、おおよそポリアミド樹脂の吸湿性によるものと考えられる。後述するように、ポリカーボネート樹脂からなるシートを保護層としてなる機能性シートにおいては、曲げ加工前に飽和状態の６割から７割程度の高水分含量の状態であっても、熱曲げ加工前に水分量を一定以下に低減することで、熱曲げ加工時における不具合を解消することができることがわかっている。しかしながら、本願発明に係るポリアミド樹脂からなるシートを保護層とする機能性シートから製造される個別レンズ用片を製造する場合、熱曲げ加工前における水分含量を低めることも重要であるが、機能性シートの段階においても水分量を一定以下とすることが重要である。   In the present invention, the effect of the invention is judged based on the moisture content of the functional sheet, but the effect of the present invention is considered to be largely due to the hygroscopicity of the polyamide resin. As will be described later, in a functional sheet having a sheet made of a polycarbonate resin as a protective layer, even in a high moisture content state of about 60% to 70% of the saturated state before bending, it is possible to prevent heat from bending. It has been found that by reducing the water content to a certain level or less, problems during hot bending can be eliminated. However, in the case of manufacturing an individual lens piece manufactured from a functional sheet having a sheet made of the polyamide resin according to the present invention as a protective layer, it is important to reduce the water content before the heat bending process, but the functionality does not improve. It is important to keep the water content below a certain level even at the sheet stage.
　一般的に機能性フィルムの両側に接着層を介して積層された保護層のみの水分含量を測定することは困難である。従って、本願発明では、偏光積層体全体に対して水分の飽和状態を含水率のｗｔ％として定め、これに対する含水率を比較して、「含水率の割合」とする。すなわち、吸湿性において飽和状態の機能性シートの「含水率」を基準とする。含水率は機能性シートを構成する樹脂や機能層の材料や量により影響を受けるものと思われる。驚くべきことに、ポリアミド樹脂からなるシートを保護層として用いた場合には、含水率の割合を所定の値以下とすることが好ましいことが確認された。このような含水率の割合としては、条件により飽和状態の含水率に対して７０％以下、６０％以下としてもよく、５０％以下に維持することが好ましく、好適には４０％以下とすることが好ましいことが確認された。さらには、当該含水率の割合は、熱曲げ加工前にさらに３０％以下、２０％以下、１５％以下とすることが好ましく、好適には１０％程度にまで低下させることも熱曲げ加工における色変化を抑制するために必要であることが確認された。 　Generally, it is difficult to measure the moisture content of only the protective layers laminated on both sides of the functional film via adhesive layers. Therefore, in the present invention, the saturated state of water in the entire polarizing laminate is defined as wt % of the water content, and the water content is compared with this to obtain the "percentage of water content". That is, the "moisture content" of the functional sheet in a saturated state of hygroscopicity is used as a reference. The water content is considered to be affected by the resin constituting the functional sheet and the material and amount of the functional layer. Surprisingly, it has been confirmed that when a sheet made of a polyamide resin is used as a protective layer, it is preferable to set the water content to a predetermined value or less. Depending on the conditions, the water content ratio may be 70% or less, 60% or less, preferably 50% or less, preferably 40% or less, with respect to the water content in the saturated state. was confirmed to be preferable. Furthermore, the percentage of the moisture content is preferably 30% or less, 20% or less, or 15% or less before hot bending, and preferably reduced to about 10%. It was confirmed that it is necessary to suppress the change.
（機能性シートの作製）
  上記した偏光フィルム層を機能層とし、上記接着層をグラビアコーター、或いはダイコーターなどで塗布して、上記保護層を両面に貼り合わせ、所望の長さに裁断することにより機能性シートとすることができる。ラミネート方法においては特に限定はないが、接着材塗工時に塗工液不足による気泡巻き込みなどを回避するために、十分な吐出量を維持する。また、貼り合わせ時の張力、及び貼り合わせロールのニップ圧などは、貼り合わせ後のシートの反り状態などを考慮して、適切に調節することが望ましい。 (Production of functional sheet)
The polarizing film layer is used as a functional layer, the adhesive layer is applied with a gravure coater or a die coater, the protective layer is attached to both sides, and the sheet is cut to a desired length to form a functional sheet. can be done. The lamination method is not particularly limited, but a sufficient discharge amount is maintained in order to avoid entrainment of air bubbles due to lack of the coating liquid during coating of the adhesive. Moreover, it is desirable to appropriately adjust the tension during lamination, the nip pressure of the lamination roll, and the like, taking into account the state of warpage of the sheet after lamination.
（機能性レンズの作製）
  次いで、機能性シートを個別レンズ用片に打ち抜き、得られた個別レンズ用片に曲面加工を施し、必要に応じ射出成形機にインサートして個別レンズ用片の凹面側に熱可塑性樹脂を射出し、機能性レンズとする。
  打ち抜き加工は、通常、トムソン刃からなる打ち抜き刃を用いることができる。通常１枚の機能性シートから複数の個別レンズ用片を打ち抜き加工により得る。個別レンズ用片の形状は、最終製品の形状（サングラス、ゴーグルなど）により適宜、選択される。二眼用の場合の標準的なレンズ形状品は、直径８０ｍｍの円盤或いはその両端を偏光軸に垂直な方向に同幅切り取ったスリット形状である。 (Production of functional lens)
Next, the functional sheet is punched out into individual lens pieces, the obtained individual lens pieces are curved, and if necessary, they are inserted into an injection molding machine and a thermoplastic resin is injected onto the concave side of the individual lens pieces. , functional lenses.
For punching, a punching blade, usually a Thomson blade, can be used. A plurality of individual lens pieces are usually obtained by punching from one functional sheet. The shape of the individual lens piece is appropriately selected according to the shape of the final product (sunglasses, goggles, etc.). A standard lens-shaped product for binocular use is a disk with a diameter of 80 mm or a slit shape obtained by cutting both ends of the disk with the same width in the direction perpendicular to the polarization axis.
  上記打ち抜き加工においては、偏光フィルム層、接着層、両表面の保護層、両表面の保護フィルムが大きく破壊されることはなく、微細な破砕片の発生や延伸方向への割れの伝搬、過剰な変形伸びなどの有無が検討対象となり、適度なねばりが必須となる。この際、偏光フィルム層が乾燥して打ち抜きされたことにより破壊され、微細な破砕片を生じさせないために、適宜吸湿させたものを用いる方法も推奨される。
  次いで、個別レンズ用片を、前乾燥処理した後、加熱下に球面或いは非球面に熱曲げしてなる熱曲げシートとする。前乾燥は、個別レンズ用片を熱曲げ加工後に、色変化しない条件を選択する。通常、６０～８０℃、好ましくは６５～７５℃で８時間以上、好ましくは２４時間程度の送風乾燥をすることによる。
  個別レンズ用片の熱曲げ加工は、金型表面に沿うように曲げられる。金型は射出成形に用いる金型であってもよい。熱曲げ加工は、平面である個別レンズ用片を、通常、部分球面、場合により楕円面のような三次元曲面とするものである。変形に伴うエネルギー最小のこのような加工は、縮みを伴う加工となり、スムースな縮みが妨げられる場合には、波、さらに皺の発生となり、良品の製造ができないものとなるので、スムースな縮みを確保するように、温度、荷重の負荷など、緩やかな過重負荷による制御を行うことが好ましい。
　加熱温度は、保護シートに用いたポリアミド樹脂のガラス転移点より５０℃低い温度以上でガラス転移点未満の温度が加工温度として選択される。好ましくは、ポリアミド樹脂のガラス転移温度より２５℃低い温度以上、より好ましくは２０℃低い温度以上でガラス転移点より５℃低い温度以下である。
  射出成形する場合の加工条件は、外観に優れたレンズが製造できることが必須である。したがって、バリの出ない範囲で充填率の高いレンズ成形品の得られる射出条件、例えば、射出圧、保持圧、計量、成形サイクルなどが、適宜選択される。樹脂温度は、ポリアミド樹脂の溶融温度、ポリアミド樹脂の組成にもよるが、通常、２３０～３２０℃から適宜選択され、好ましくは２５０～３００℃である。射出圧力は５０～２００ＭＰａから適宜選択される。
  また、金型温度はポリアミド樹脂のＴｇより１００℃低い温度以上乃至Ｔｇ未満の温度から選択され、好ましくは７０～１２０℃である。
  射出成形に用いる熱可塑性樹脂はポリアミド樹脂であることが好ましく、非晶性ポリアミドと称されるものがより好ましい。熱可塑性で、熱分解温度以下で成形可能な溶融流動性を示し、適度のＴｇ（ガラス転移温度）を有するものであれば良いが、機能性シートとの界面の外観を損ねないように、機能性シートに用いるポリアミド樹脂と同じ、または、それと屈折率の近いポリアミド樹脂を選択することが好ましい。 In the above punching process, the polarizing film layer, the adhesive layer, the protective layers on both surfaces, and the protective films on both surfaces are not greatly destroyed, and the generation of fine fragments, the propagation of cracks in the stretching direction, and excessive The presence or absence of deformation elongation is an object of examination, and appropriate tenacity is essential. In this case, it is also recommended to use a polarizing film layer that has been appropriately moisture-absorbed in order to prevent the polarizing film layer from being dried and broken by being punched to produce fine fragments.
Next, the individual lens piece is pre-dried and then thermally bent into a spherical or aspherical surface under heating to form a thermally bent sheet. For the pre-drying, conditions are selected that do not change the color after the individual lens piece is thermally bent. Usually, it is dried at 60 to 80° C., preferably 65 to 75° C. for 8 hours or more, preferably about 24 hours.
The thermal bending process of the individual lens piece is bent along the mold surface. The mold may be a mold used for injection molding. Thermal bending is the process of converting a planar individual lens piece into a three-dimensional curved surface, usually a partial spherical surface, and possibly an ellipsoidal surface. Such processing with minimal energy associated with deformation results in shrinkage, and if smooth shrinkage is hindered, waves and wrinkles occur, making it impossible to manufacture good products. It is preferable to control the temperature, the loading of the load, etc. by a gradual overloading so as to ensure that.
As for the heating temperature, a processing temperature is selected that is at least 50° C. lower than the glass transition point of the polyamide resin used for the protective sheet and below the glass transition point. It is preferably at least 25°C lower than the glass transition temperature of the polyamide resin, more preferably at least 20°C lower than the glass transition temperature and at most 5°C lower than the glass transition point.
Processing conditions for injection molding must be such that lenses with excellent appearance can be produced. Therefore, the injection conditions such as injection pressure, holding pressure, metering, molding cycle, etc., are appropriately selected so that a lens molded product with a high filling rate can be obtained within a range in which burrs do not occur. The resin temperature is usually appropriately selected from 230 to 320°C, preferably 250 to 300°C, although it depends on the melting temperature of the polyamide resin and the composition of the polyamide resin. The injection pressure is appropriately selected from 50 to 200 MPa.
Further, the mold temperature is selected from a temperature not less than 100°C lower than the Tg of the polyamide resin and less than the Tg, preferably 70 to 120°C.
The thermoplastic resin used for injection molding is preferably a polyamide resin, more preferably a so-called amorphous polyamide. It is thermoplastic, exhibits moldable melt fluidity below the thermal decomposition temperature, and has an appropriate Tg (glass transition temperature). It is preferable to select a polyamide resin having a refractive index that is the same as or close to that of the polyamide resin used for the optical sheet.
  上記にて製造した機能性レンズは、適宜、ハードコート処理が施され、さらに、ミラーコートや反射防止コート等が施されて、製品とされる。
  ハードコートの材質或いは加工条件は、外観や下地のポリアミドに対して、或いは続いてコートされるミラーコートや反射防止コート等の無機層に対する密着性に優れている必要があり、この点から、ハードコートの焼成温度はポリアミド樹脂のガラス転移点より５０℃低い温度以上でガラス転移点未満の温度が好ましく、特に、ガラス転移点より４０℃低い温度以上でガラス転移点より１５℃低い温度未満であることがより好ましく、３０℃前後低い温度であることが最も好ましい。ハードコートの焼成時間は概ね０．５～２時間である。 The functional lens manufactured as described above is appropriately subjected to a hard coating treatment, and further subjected to a mirror coating, an antireflection coating, or the like, to obtain a product.
The material and processing conditions of the hard coat must be excellent in appearance and adhesion to the underlying polyamide, or to the subsequently coated inorganic layer such as mirror coat or antireflection coat. The baking temperature of the coat is preferably at least 50°C lower than the glass transition point of the polyamide resin and lower than the glass transition point, particularly at least 40°C lower than the glass transition point and lower than 15°C lower than the glass transition point. is more preferable, and a temperature lower than about 30°C is most preferable. The firing time of the hard coat is approximately 0.5 to 2 hours.
  上記で製造された機能性レンズは、レンズメーカーにて、最終製品であるサングラスやゴーグルなどに加工されて販売され、また、個別の販売店（小売店）にて、玉摺り、穴あけ、ネジ締めなど、様々な製品用にレンズ加工がなされてサングラスやゴーグルなどとして販売される。 The functional lenses manufactured above are processed into final products such as sunglasses and goggles by lens manufacturers and sold. Lens processing is done for various products such as, and sold as sunglasses and goggles.
（含水率の測定）
実施例、比較例の含水率は赤外線水分計（株式会社フジワーク製、ＩＭ－３ＳＲＶ　ＭＯＤＥＬ－１０００）を用いて測定した。
事前にガス圧水分計（Ｂｒａｂｅｎｄｅｒ　Ｍｅｓｓｔｅｃｈｎｉｋ　ＧｍｂＨ　＆　Ｃｏ．　ｋｇ社製、ＡＱＵＡＴＲＡＣ　３Ｅ）を用いて赤外線水分計の測定値に対する含水率の検量線を作成した。 (Measurement of moisture content)
The water content in Examples and Comparative Examples was measured using an infrared moisture meter (IM-3SRV MODEL-1000, manufactured by Fuji Work Co., Ltd.).
Using a gas pressure moisture meter (AQUATRAC 3E, manufactured by Brabender Messtechnik GmbH & Co. kg) in advance, a calibration curve of moisture content relative to measured values of the infrared moisture meter was prepared.
　熱曲げ加工前に含水率の割合を下げるために実施例では、７０℃で２０時間の乾燥工程を実施した。比較例の試験片については、７０℃もしくは８０℃で加熱時間を４～２０時間とした。 In order to lower the moisture content before hot bending, in the example, a drying process was performed at 70°C for 20 hours. The specimens of the comparative examples were heated at 70° C. or 80° C. for 4 to 20 hours.
（偏光フィルムの製造）
Ａ  ポリビニルアルコール（クラレ株式会社製、商品名：ＶＦ－ＰＳ＃７５００）を３５℃の水中で２７０秒間膨潤しつつ、２倍に延伸した。
  引き続いて、Ｃｈｒｙｓｏｐｈｅｎｉｎｅ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｙｅｌｌｏｗ１２）、Ｓｕｍｉｌｉｇｈｔ　Ｒｅｄ  ４Ｐ－Ｂ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｒｅｄ８１）、Ｓｕｍｉｌｉｇｈｔ  Ｓｕｐｒａ  Ｂｌｕｅ  Ｇ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｂｌｕｅ７８）及び１０ｇ／Ｌの無水硫酸ナトリウムを含む３５℃の水溶液中で染色した。
  この染色フィルムを酢酸ニッケル２．３ｇ／Ｌおよびホウ酸４．４ｇ／Ｌを含む水溶液中３５℃で１２０秒間浸漬しつつ、４倍に延伸した。そのフィルムを緊張状態が保持された状態で室温で３分乾燥を行った後、１１０℃で３分間加熱処理し、偏光フィルムを得た。
Ｂ  ポリビニルアルコール（クラレ株式会社製、商品名：ＶＦ－ＰＳ＃７５００）を３５℃の水中で２７０秒間膨潤しつつ、２倍に延伸した。
  引き続いて、Ｃｈｒｙｓｏｐｈｅｎｉｎｅ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｙｅｌｌｏｗ１２）、Ｓｕｍｉｌｉｇｈｔ　Ｒｅｄ  ４Ｐ－Ｂ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｒｅｄ８１）、Ｓｕｍｉｌｉｇｈｔ  Ｓｕｐｒａ  Ｂｌｕｅ  Ｇ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｂｌｕｅ７８）及び１０ｇ／Ｌの無水硫酸ナトリウムを含む３５℃の水溶液中で染色した。
  この染色フィルムを酢酸ニッケル２．３ｇ／Ｌおよびホウ酸４．４ｇ／Ｌを含む水溶液中３５℃で１２０秒間浸漬しつつ、４倍に延伸した。そのフィルムを緊張状態が保持された状態で室温で３分乾燥を行った後、１１０℃で３分間加熱処理し、偏光フィルムを得た。
Ｃ  ポリビニルアルコール（クラレ株式会社製、商品名：ＶＦ－ＰＥ＃６０００）を３５℃の水中で２７０秒間膨潤しつつ、２倍に延伸した。
  引き続いて、Ｋａｙａｒｕｓ  Ｓｕｐｒａ  Ｏｒａｎｇｅ ２ＧＬ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｏｒａｎｇｅ３９）、Ｓｕｍｉｌｉｇｈｔ　Ｒｅｄ  ４Ｐ－Ｂ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｒｅｄ８１）、Ｋａｙａｒｕｓ　Ｓｕｐｒａ　Ｂｌｕｅ　ＢＷＬ（Ｃ．Ｉ．Ｄｉｒｅｃｔ  Ｂｌｕｅ２３７）及び１０ｇ／Ｌの無水硫酸ナトリウムを含む３５℃の水溶液中で染色した。
  この染色フィルムを酢酸ニッケル２．３ｇ／Ｌおよびホウ酸４．４ｇ／Ｌを含む水溶液中３５℃で１２０秒間浸漬しつつ、５倍に延伸した。そのフィルムを緊張状態が保持された状態で室温で３分乾燥を行った後、１１０℃で３分間加熱処理し、偏光フィルムを得た。 (Manufacture of polarizing film)
A Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: VF-PS#7500) was swelled in water at 35° C. for 270 seconds while being stretched twice.
followed by Chrysophene (CI Direct Yellow 12), Summit Red 4P-B (CI Direct Red 81), Summit Supra Blue G (CI Direct Blue 78) and 35 containing 10 g/L anhydrous sodium sulfate It was dyed in an aqueous solution at ℃.
This dyed film was immersed in an aqueous solution containing 2.3 g/L of nickel acetate and 4.4 g/L of boric acid at 35° C. for 120 seconds while being stretched 4 times. The film was dried at room temperature for 3 minutes while being kept in tension, and then heat-treated at 110° C. for 3 minutes to obtain a polarizing film.
B Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: VF-PS#7500) was swelled in water at 35° C. for 270 seconds and stretched twice.
followed by Chrysophene (CI Direct Yellow 12), Summit Red 4P-B (CI Direct Red 81), Summit Supra Blue G (CI Direct Blue 78) and 35 containing 10 g/L anhydrous sodium sulfate It was dyed in an aqueous solution at ℃.
This dyed film was immersed in an aqueous solution containing 2.3 g/L of nickel acetate and 4.4 g/L of boric acid at 35° C. for 120 seconds while being stretched 4 times. The film was dried at room temperature for 3 minutes while being kept in tension, and then heat-treated at 110° C. for 3 minutes to obtain a polarizing film.
C Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: VF-PE#6000) was swelled in water at 35° C. for 270 seconds while being stretched twice.
followed by Kayarus Supra Orange 2GL (CI Direct Orange 39), Summit Red 4P-B (CI Direct Red 81), Kayarus Supra Blue BWL (CI Direct Blue 237) and 10 g/L anhydrous sodium sulfate dyed in an aqueous solution at 35°C containing
This dyed film was immersed in an aqueous solution containing 2.3 g/L of nickel acetate and 4.4 g/L of boric acid at 35° C. for 120 seconds while being stretched 5 times. The film was dried at room temperature for 3 minutes while being kept in tension, and then heat-treated at 110° C. for 3 minutes to obtain a polarizing film.
  得られた偏光フィルムの光吸収波長の青（４５０ｎｍ）、緑（５５０ｎｍ）、赤（６５０ｎｍ）における二色比を表１に示した。二色比は次式により求めた。
  二色比＝Ａｚ／Ａｘ
  ここで、Ａｘは最大透過方向の直線偏光の吸光度を表し、Ａｚは最大透過方向に直交する方向の直線偏光の吸光度を表す。ＡｘおよびＡｚは、島津製作所社製の分光光度計（ＵＶ－３６００）を用いてサンプルに直線偏光を入射させて測定した。 Table 1 shows the dichroic ratio of the obtained polarizing film at light absorption wavelengths of blue (450 nm), green (550 nm) and red (650 nm). The dichroic ratio was obtained by the following formula.
Dichroic ratio = Az/Ax
Here, Ax represents the absorbance of linearly polarized light in the maximum transmission direction, and Az represents the absorbance of linearly polarized light in the direction orthogonal to the maximum transmission direction. Ax and Az were measured using a spectrophotometer (UV-3600 manufactured by Shimadzu Corporation) by illuminating the sample with linearly polarized light.
  次に得られた偏光フィルムの偏光度、およびクロスニコル配置時の色調を表１に示した。偏光度は次式により求めた。
  偏光度＝１００×（τｐｍａｘ－τｐｍｉｎ）／（τｐｍａｘ＋τｐｍｉｎ）
  ここで、τｐｍａｘは直線偏光を入射して測定した視感透過率の最大値を表し、τｐｍｉｎは直線偏光を入射して測定した視感透過率の最小値を表す。τｐｍａｘおよびτｐｍｉｎは、ＡｘおよびＡｚを視感透過率として表した値である。
  クロスニコル配置時の色調は、クロスニコル配置時には偏光フィルムに入射した光が透過軸、吸収軸にそれぞれ吸収されることから、クロスニコル配置時のスペクトルはＡｚ×Ａｘで表すことができ、そこからＬ＊ａ＊ｂ＊表色系を用いて算出した。
  クロスニコル配置時の色調はｂ＊値が低く、青みを帯びてみえるが、偏光度は９９％を上回っており、実用上なんら問題はない。
（偏光フィルムの作製）
  次いで、ポリビニルアルコールフィルム（クラレ株式会社製）を３５℃の水中で膨潤させ、その後、二色性色素Ｓｕｍｉｌｉｇｈｔ  Ｓｕｐｒａ  Ｂｌｕｅ  Ｇ（Ｃ.Ｉ.  Ｂｌｕｅ  ７８）、Ｓｕｍｉｌｉｇｈｔ　Ｒｅｄ  ４Ｐ－Ｂ（Ｃ.Ｉ.  Ｒｅｄ  ８１）、Ｃｈｒｙｓｏｐｈｅｎｉｎｅ（Ｃ.Ｉ.  Ｙｅｌｌｏｗ  １２）及び１０ｇ／Lの無水硫酸ナトリウムを含む３５℃の水溶液中で染色し、酢酸ニッケル２．５ｇ／L、ホウ酸５ｇ／Lを含む３５℃の水溶液中に浸漬して最終的に４倍の倍率になるように延伸した。そのフィルムを緊張状態が保持された状態で、１１０℃で３分間加熱処理し、偏光フィルムを得、低湿度保管庫にて次工程までの間保管した。 Table 1 shows the degree of polarization of the obtained polarizing film and the color tone when arranged in crossed Nicols. The degree of polarization was determined by the following formula.
Degree of polarization = 100 × (τpmax-τpmin) / (τpmax + τpmin)
Here, τpmax represents the maximum value of luminous transmittance measured with incident linearly polarized light, and τpmin represents the minimum value of luminous transmittance measured with incident linearly polarized light. τpmax and τpmin are values representing Ax and Az as luminous transmittance.
The color tone in the crossed nicols arrangement can be expressed by Az×Ax because the light incident on the polarizing film is absorbed by the transmission axis and the absorption axis in the crossed nicols arrangement, respectively. Calculated using the L*a*b* color system.
The color tone in the crossed nicols configuration has a low b* value and looks bluish, but the degree of polarization exceeds 99%, and there is no practical problem.
(Preparation of polarizing film)
Next, a polyvinyl alcohol film (manufactured by Kuraray Co., Ltd.) is swelled in water at 35 ° C., and then dichroic dyes Summit Supra Blue G (C.I. Blue 78) and Summit Red 4P-B (C.I. Red 81), dyed in an aqueous solution at 35°C containing chrysophene (C.I. Yellow 12) and 10 g/L of anhydrous sodium sulfate; The film was immersed in the medium and stretched to a final magnification of 4 times. The film was heat-treated at 110° C. for 3 minutes while being kept in tension to obtain a polarizing film, which was stored in a low-humidity storage until the next step.
  （ポリアミドシートの作製）
  （ＰＡ１）：脂肪族、及び脂環族からなる非晶質透明ポリアミド樹脂（ＥＭＳ－ＣＨＥＭＩＥ社、Ｇｒｉｌａｍｉｄ  ＴＲ９０）を加熱溶解し、短軸押出し機でＴダイから溶融樹脂を押出し、冷却ロールで冷却後に巻き取り機で巻き取る溶融押し出し製法にて、Ｔｇが１５５℃、厚み３００μｍ、リタデーションが５０ｎｍの非延伸ポリアミドシート（以下ＰＡ１と記す）を作製した。なお、製造したすべてのポリアミドシートは製造後ただちに低湿度保管庫にて保管した。
  （ＰＡ２）：厚みを５３０μｍとした以外はＰＡ１と同様にして得たポリアミドシートを１０ｃｍ角に切り出し、四方をクランプで固定してＰＡ１のＴｇ（ＤＳＣ測定における中間点）温度で２０分保持した後、１．５倍の延伸倍率で一軸方向のみに延伸して、延伸後緊張状態を保持したまま室温で３０分間冷却して、リタデーションが４０００ｎｍである延伸ポリアミドシート（以下ＰＡ２と記す）を得た。
  なお、酸素透過度の測定は、２３℃、８５％ＲＨにて、ＯＸ－ＴＲＡＮ  ２／６１（ＭＯＣＯＮ社製）を用いて行った。リタデーション値は、大塚電子製リタデーション測定装置：ＲＥＴＳ－１００を用いて波長５９０ｎｍにて測定した値である。 (Production of polyamide sheet)
(PA1): Aliphatic and alicyclic amorphous transparent polyamide resin (EMS-CHEMIE, Grilamid TR90) is heated and melted, the molten resin is extruded from a T-die with a short screw extruder, and cooled with a cooling roll. A non-stretched polyamide sheet (hereinafter referred to as PA1) having a Tg of 155° C., a thickness of 300 μm, and a retardation of 50 nm was produced by a melt extrusion method in which the sheet was later wound up with a winder. All the produced polyamide sheets were stored in a low-humidity storage immediately after production.
(PA2): A polyamide sheet obtained in the same manner as PA1 except that the thickness was 530 μm was cut into 10 cm squares, fixed on all sides with clamps, and held at the Tg (middle point in DSC measurement) temperature of PA1 for 20 minutes. , stretched only in the uniaxial direction at a draw ratio of 1.5 times, and cooled at room temperature for 30 minutes while maintaining the tension after stretching to obtain a stretched polyamide sheet (hereinafter referred to as PA2) having a retardation of 4000 nm. .
The oxygen permeability was measured at 23° C. and 85% RH using OX-TRAN 2/61 (manufactured by MOCON). The retardation value is a value measured at a wavelength of 590 nm using a retardation measuring device: RETS-100 manufactured by Otsuka Electronics.
（機能性シートの作製）
　上記で取得したＰＡ１に熱硬化性ポリウレタン系接着剤を塗布して、上記で取得した偏光フィルムを積層し、偏光フィルムの残りの片面へ同じようにＰＡ２を積層した。積層後、７０℃の恒温槽に放置して接着剤を硬化させ、機能性シートを得た。
　得られた機能性シートは、２５℃（±５℃）および湿度１０％（－５～＋１０％）に管理された部屋に機能性シートを積層した状態で保管された。 (Production of functional sheet)
A thermosetting polyurethane adhesive was applied to PA1 obtained above, the polarizing film obtained above was laminated, and PA2 was laminated in the same manner on the remaining one side of the polarizing film. After lamination, the adhesive was cured by standing in a constant temperature bath at 70° C. to obtain a functional sheet.
The obtained functional sheets were stored in a laminated state in a room controlled at 25° C. (±5° C.) and humidity of 10% (−5 to +10%).
（個別レンズ用片の作製）
  上記で取得した機能性シートを、直径８０ｍｍの円盤をその中心を通る直線の両側を平行に同量切り取り幅５５ｍｍとしたスリット形状に切り出て、個別レンズ用片とし、色調を測定した。
（含水率の測定） (Fabrication of pieces for individual lenses)
The functional sheet obtained above was cut from a disk with a diameter of 80 mm into a slit shape with a width of 55 mm by cutting the same amount in parallel on both sides of a straight line passing through the center, and the color tone was measured.
(Measurement of moisture content)
  個別レンズ用片を４０℃９０％に管理された部屋で２週間吸湿させた。吸湿が飽和に達したかどうかについては、２週間以降数回測定し確認のうえ、本実施例の個別レンズ用片においては４０℃９０％に管理された部屋で２週間で含水率の飽和に達することを確認した。   The pieces for individual lenses were allowed to absorb moisture for two weeks in a room controlled at 40°C and 90%. Whether or not the moisture absorption reached saturation was confirmed by measuring several times after two weeks. confirmed to be reached.
  次いで、温湿度が管理された部屋で保管された機能性シートを直ちに打ち抜いた個別レンズ用片の含水率を測定した。飽和状態の個別レンズ用片と実施例の個別レンズ用片の含水率から、「含水率の割合」を算出した。「含水率の割合」は以下の表に記載する。 Next, the moisture content of the individual lens piece punched out immediately from the functional sheet stored in a room with controlled temperature and humidity was measured. The "percentage of water content" was calculated from the water content of the individual lens piece in the saturated state and the individual lens piece of the example. The "percentage of moisture content" is given in the table below.
（乾燥工程）
　個別レンズ用片を７０～８０℃で２０時間乾燥を行った。２０時間経過後、比較例および実施例の個別レンズ用片の含水率を測定した。 (Drying process)
The individual lens pieces were dried at 70-80° C. for 20 hours. After 20 hours, the water content of the individual lens pieces of Comparative Example and Example was measured.
（熱曲げ加工）
　雰囲気温度１２５℃にて予備加熱し、雌型は６Ｒ相当（半径約６５．６ｍｍ）の部分球面で表面温度１３５℃、シリコンゴム製雄型による押し付け時間を４秒、雌型への真空引きにより吸着させ、吹き込み熱風温度が１５０℃である雰囲気下で８分間保持し、熱曲げ個別レンズ用片を作成し、色調を測定した。 (Thermal bending process)
Pre-heating at an ambient temperature of 125°C, the female mold has a partial spherical surface equivalent to 6R (radius of about 65.6 mm), the surface temperature is 135°C, the pressing time with the silicone rubber male mold is 4 seconds, and the female mold is vacuumed. It was made to adsorb and held for 8 minutes in an atmosphere with a hot air blowing temperature of 150° C. to prepare a thermal bending individual lens piece, and the color tone was measured.
（色変化の測定）
　個別レンズ用片および熱曲げ後の個別レンズ用片において、機能性シートの透過率と色調を島図製作所製の分光光度計（ＵＶ－３６００）を用いて測定した。また、曲げ加工後の個別レンズ用片の透過率と色調も同様に測定し、色差ΔＥ＊ａｂを求めた。色差は次式により求めた。
色差：ΔＥ＊ａｂ＝（（ΔＬ＊）＾２＋（Δａ＊）＾２＋（Δｂ＊）＾２）＾（１／２） (Measurement of color change)
The transmittance and color tone of the functional sheet of the individual lens pieces and the thermally bent individual lens pieces were measured using a spectrophotometer (UV-3600) manufactured by Shimazu Seisakusho. Similarly, the transmittance and color tone of the individual lens pieces after bending were measured to obtain the color difference ΔE*ab. The color difference was obtained by the following formula.
Color difference: ΔE*ab=((ΔL*)^2+(Δa*)^2+(Δb*)^2)^(1/2)
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　偏光色素の違いにより、色差の良否が異なるが、上記いずれの実施例においても、乾燥工程前のポリアミド偏光積層体からなる個別レンズ用片にて、乾燥工程前の含水率の割合を５０％以下とし、個別レンズ用片を曲げ加工する前にこの含水率の割合を１５％以下とすることで、熱曲げ加工による色差の少ない個別レンズ用片を製造することが可能になった。 Although the quality of the color difference differs depending on the difference in the polarizing dye, in any of the above examples, the individual lens piece made of the polyamide polarizing laminate before the drying process has a moisture content of 50% or less before the drying process. By setting the water content to 15% or less before bending the individual lens pieces, it is possible to produce individual lens pieces with little color difference due to thermal bending.
　比較例１および２と、比較例３との比較から明らかなように、乾燥工程前または曲げ加工前のいずれか一方の段階で、含水率の割合を所定の値とすることは色差を小さくすることは不可能である。また、比較例４および５と比較例６との比較、比較例７および８と比較例９との比較より、このことは偏光フィルムに吸着させた色素に異存するものでもないことも明確である。 As is clear from the comparison between Comparative Examples 1 and 2 and Comparative Example 3, setting the water content to a predetermined value either before the drying step or before the bending process reduces the color difference. is impossible. In addition, it is clear from the comparison between Comparative Examples 4 and 5 and Comparative Example 6, and the comparison between Comparative Examples 7 and 8 and Comparative Example 9, that this does not depend on the dye adsorbed on the polarizing film. .
　このような色差が生じる原因は、ポリアミド樹脂の吸湿による影響であると考えられた。したがって、本願発明において、ポリアミド樹脂を個別レンズ用片として効率よく製造することが可能となった。 It was thought that the cause of such color difference was the influence of moisture absorption of the polyamide resin. Therefore, in the present invention, it has become possible to efficiently manufacture polyamide resin pieces for individual lenses.

Claims (8)

  1.   ポリビニルアルコール系偏光フィルム層、調光層またはこれらの組み合わせである機能層の少なくとも片面に接着層を介して、ポリアミド樹脂からなる透明プラスチックシート或いはフィルムによる保護層が配置されてなる機能性シートから、個別レンズ用片を製造する方法であって、
    ａ）ポリビニルアルコール系偏光フィルム層、調光層またはこれらの組み合わせである機能層の少なくとも片面に接着層を介して透明プラスチックシート或いはフィルムによる保護層が配置されてなる機能性シートを製造する工程、
    ｂ）前記機能性シートを吸湿しないよう保管する工程、および
    ｃ）前記機能性シートを個別レンズ用片に打ち抜く工程、を含み
    ｂ）の前記機能性シートを吸湿しないよう保管する工程からｃ）の前記機能性シートを前記機能性シートを個別レンズ用片に打ち抜く工程において、水分含量を飽和させた機能性シートの含水率を１００％としたとき、前記機能性シートの含水率の割合が５０％を超えないように保管することを特徴とする、個別レンズ用片の製造方法。     A functional sheet comprising a protective layer made of a transparent plastic sheet or film made of a polyamide resin disposed on at least one side of a functional layer that is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof, via an adhesive layer, A method of manufacturing individual lens pieces, comprising:
    a) A step of producing a functional sheet comprising a protective layer made of a transparent plastic sheet or film disposed on at least one side of a functional layer that is a polyvinyl alcohol-based polarizing film layer, a light control layer, or a combination thereof via an adhesive layer,
    b) storing the functional sheet so as not to absorb moisture; and c) punching the functional sheet into pieces for individual lenses. In the step of punching the functional sheet into individual lens pieces, the water content ratio of the functional sheet is 50% when the water content of the functional sheet saturated with water content is 100%. A method of manufacturing an individual lens piece, characterized in that the piece is stored so as not to exceed .
  2.   更に、ｄ）前記個別レンズ用片を熱曲げ加工する工程、を含み、
    ｄ）の前記個別レンズ用片を熱曲げ加工する工程を行う前に、前記含水率の割合を１５％以下にするための更なる乾燥工程を行うことを特徴とする、個別レンズ用片の製造方法。     Furthermore, d) the step of thermally bending the individual lens pieces,
    Manufacture of individual lens pieces, characterized in that, before performing the step of thermally bending the individual lens pieces in d), a further drying step is performed to reduce the moisture content to 15% or less. Method.
  3.   前記保護層が非晶性或いは微結晶性ポリアミド樹脂からなることを特徴とする、請求項１または２に記載の個別レンズ用片の製造方法。 3. The method of manufacturing an individual lens piece according to claim 1 or 2, wherein the protective layer is made of an amorphous or microcrystalline polyamide resin.
  4.   前記接着層が、ウレタン樹脂系接着剤からなる事を特徴とする、請求項１、２または３のいずれか1項に記載の個別レンズ用片の製造方法。 4. The method for manufacturing individual lens pieces according to claim 1, wherein the adhesive layer is made of a urethane resin adhesive.
  5.   前記保護層のリタデーション値が、２００ｎｍ以下、２０００ｎｍ以上、或いはこれらの組み合わせであることを特徴とする、請求項１ないし４のいずれかに記載の個別レンズ用片の製造方法。 5. The method of manufacturing an individual lens piece according to any one of claims 1 to 4, wherein the protective layer has a retardation value of 200 nm or less, 2000 nm or more, or a combination thereof.
  6.   前記保護層の少なくとも片面が延伸処理されていないことを特徴とする、請求項１～５に記載の個別レンズ用片の製造方法。 The method for manufacturing an individual lens piece according to any one of claims 1 to 5, wherein at least one surface of the protective layer is not stretched.
  7.   さらに、前記熱曲げ加工されたレンズ用片の凹面側に熱可塑性樹脂を熱融着する工程を含む、請求項１～６に記載の個別レンズ用片の製造方法。 The method for manufacturing the individual lens piece according to any one of claims 1 to 6, further comprising the step of heat-sealing a thermoplastic resin to the concave surface side of the thermally bent lens piece.
  8.   請求項１～８いずれかに記載の個別レンズ用片の製造方法により製造された機能性レンズ。

          A functional lens manufactured by the method for manufacturing an individual lens piece according to any one of claims 1 to 8.
PCT/JP2022/026041 2021-08-02 2022-06-29 Polarizing sheet and method for manufacturing same WO2023013315A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7931369B2 (en) * 2007-07-13 2011-04-26 David Andrew Harris Tinted lens and method of making same
WO2016067937A1 (en) * 2014-10-31 2016-05-06 株式会社ウインテック Package of heat-bent polarizing sheet and injection-molded polarizing lens
WO2019013078A1 (en) * 2017-07-10 2019-01-17 三菱瓦斯化学株式会社 Functional sheet
WO2019049835A1 (en) * 2017-09-07 2019-03-14 ダイセル・エボニック株式会社 Polarizing sheet and polarizing lens provided with same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7931369B2 (en) * 2007-07-13 2011-04-26 David Andrew Harris Tinted lens and method of making same
WO2016067937A1 (en) * 2014-10-31 2016-05-06 株式会社ウインテック Package of heat-bent polarizing sheet and injection-molded polarizing lens
WO2019013078A1 (en) * 2017-07-10 2019-01-17 三菱瓦斯化学株式会社 Functional sheet
WO2019049835A1 (en) * 2017-09-07 2019-03-14 ダイセル・エボニック株式会社 Polarizing sheet and polarizing lens provided with same

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