JP5884420B2 - Triacetylcellulose laminate, optical film and optical member using the same - Google Patents

Description

  The present invention relates to an optical member used in an image display device such as a liquid crystal display, and more specifically, when a triacetyl cellulose (hereinafter also referred to as “TAC”) substrate and an adherend are laminated via an adhesive layer. Furthermore, it is related with the laminated body which can prevent the adhesion film of a TAC base material from floating to a to-be-adhered body even under high temperature and humidity.

  A TAC film is used as an optical film constituting an image display device such as a liquid crystal display. TAC has the role of protecting the polarizing plate. If necessary, the hard coat layer for imparting scratch resistance to the surface and the anti-reflection function while maintaining the scratch resistance make it easy to view the liquid crystal screen. There is a type in which an antireflection layer or the like that contributes to the improvement of the thickness is formed.

  The TAC film is laminated with a polarizing plate or a glass substrate via an adhesive layer and used as an optical member. However, since TAC generally has a property of shrinking under wet heat conditions, there is a problem that the adhesive film of the TAC base material floats from the adherend under high temperature and high humidity.

  In order to solve this problem, for example, Patent Document 1 discloses that, in addition to an acrylic pressure-sensitive adhesive and an isocyanate-based curing agent, a peroxide is contained in combination with a thermal decomposition reaction using a peroxide. Maintaining stress relaxation properties is disclosed.

  Patent Document 2 discloses that an adhesive layer obtained by crosslinking a layer made of an adhesive composition has a storage elastic modulus (G ′) at 23 ° C. of 32000 to 70000 Pa and a storage elastic modulus (G ′) at 80 ° C. Discloses a method for producing a pressure-sensitive adhesive layer for an optical member, comprising a step of heat-treating a layer made of the pressure-sensitive adhesive composition so that the pressure becomes 20000 to 45000 Pa.

JP 2006-183022 A JP 2006-316181 A

  As is clear from the examples, the pressure-sensitive adhesives of Patent Documents 1 and 2 both contain a peroxide, thereby using a thermal decomposition reaction with the peroxide and maintaining sufficient stress relaxation properties. It is.

  However, when a peroxide is contained as a third component other than the curing agent, the remaining peroxide causes a problem that the cross-linking reaction proceeds with time and the adhesive physical properties are changed. A problem arises in that the pressure-sensitive adhesive deteriorates with time because it decomposes with light or heat and generates radicals. For this reason, a method of suppressing floating and peeling without containing a peroxide has been desired.

  The present invention has been made in view of the above circumstances, and its object is to laminate a TAC substrate and an adherend via an adhesive layer, even under high temperature and high humidity, It is providing the laminated body which can prevent the adhesion film of a TAC base material from floating to a to-be-adhered body.

  The present inventor has conducted extensive research to solve the above problems, and found that the above problems can be solved by combining an acrylic pressure-sensitive adhesive, an isocyanate curing agent, and an acrylic copolymer, The present invention has been completed. Specifically, the present invention provides the following.

  (1) The present invention is a laminate in which an adhesive layer is formed on a triacetyl cellulose substrate, and the adhesive layer contains an acrylic adhesive, an isocyanate curing agent, and an acrylic copolymer. The tan δ (60 ° C.) / Tan δ (20 ° C.), which is the ratio of the loss tangent at 60 ° C. to the loss tangent at 20 ° C. of the adhesive layer, is a laminate of 1.1 or more and less than 1.3.

  (2) Moreover, this invention is a laminated body of (1) description in which the said acrylic copolymer consists of a methacrylic ester polymer block and an acrylate polymer block.

  (3) Moreover, this invention is M- of the weight average molecular weights 10,000-300,000 in which the said acrylic copolymer consists of a methyl methacrylate polymer block (M) and a butyl acrylate polymer block (A). The laminate according to (1), which is an AM type triblock copolymer.

  (4) Moreover, this invention is a laminated body in any one of (1) to (3) whose weight average molecular weights of the said acrylic adhesive are 800,000 or more and 2 million or less.

  (5) Moreover, this invention is 0.2 mass part or more and 1.0 mass part or less in conversion of solid content with respect to 100 mass parts of solid content of the said acrylic adhesive, (1) ) To (4).

  (6) Moreover, this invention is a laminated body in any one of (1) to (5) whose thickness of the said adhesion layer is 5 micrometers or more and 100 micrometers or less.

  (7) Moreover, this invention is a laminated body in any one of (1) to (6) in which the said adhesion layer further contains an adipate ester plasticizer or a phthalate ester plasticizer.

  (8) Moreover, this invention forms a hard-coat layer and an antireflection layer in the surface on the opposite side to the said adhesion layer of the said triacetyl cellulose base material in the laminated body in any one of (1) to (7). Optical film.

  (9) Moreover, this invention is an optical member by which the said triacetyl cellulose base material and a polarizing plate are laminated | stacked through the said adhesion layer in the optical film of (8) description.

  According to the laminate of the present invention, when the TAC substrate and the adherend are laminated through the adhesive layer, the shrinkage of the TAC substrate is achieved without using peroxide even under high temperature and high humidity. Stress can be relieved and the adhesive film of the TAC substrate can be prevented from floating from the adherend.

It is sectional drawing of the optical member which shows typically the structure of the optical member which concerns on embodiment of this invention.

  Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. can do.

<Triacetyl cellulose laminate>
In the triacetylcellulose laminate of the present invention, an adhesive layer is formed on a triacetylcellulose base material, and this adhesive layer requires an acrylic adhesive, an isocyanate curing agent, and an acrylic copolymer as main ingredients. Ingredients. Hereinafter, these components will be described.

[Triacetyl cellulose base material]
Triacetyl cellulose (TAC) is preferable as a base material of an optical film in terms of excellent incombustibility, transparency, surface appearance, and electrical insulation. TAC has the property of shrinking in a wet and heat environment, but when the adhesive layer has a certain thickness and elasticity, the TAC substrate's adhesive film is relaxed and the TAC substrate's adhesive film floats off the adherend. Can be prevented.

  The thickness of the TAC substrate is not particularly limited and can be appropriately selected depending on the application. Usually, it is 50 μm or more and 150 μm or less, preferably 50 μm or more and 100 μm or less. If the thickness is less than the above range, the mechanical strength may be insufficient, and breakage may occur due to warpage under wet heat conditions. If the thickness is more than the above range, excessive performance may increase the cost.

  The method for forming the TAC substrate is not particularly limited, and for example, a conventionally known film forming method such as a solution casting method, a melt extrusion method, or a calendar method can be used. Moreover, you may use the commercially available base material previously formed into a film form by the said method.

  In addition, you may perform well-known easy-adhesion processes, such as a corona discharge process, a plasma process, an ozone process, a flame process, a primer process, a preheating process, a dust removal process, a vapor deposition process, an alkali process, to a base material.

[Acrylic adhesive]
Then, an acrylic adhesive is demonstrated. A preferable acrylic pressure-sensitive adhesive includes, for example, an acrylate copolymer obtained by copolymerizing an acrylate ester with another monomer. Examples of the acrylate ester include ethyl acrylate, acrylate-n-butyl, acrylate-2-ethylhexyl, isooctyl acrylate, isononyl acrylate, hydroxylethyl acrylate, propylene glycol acrylate, acrylamide, glycidyl acrylate, and the like. Is mentioned. These can be used alone or in combination of two or more. In the present invention, among the acrylate esters, acrylate-n-butyl and acrylate-2-ethylhexyl are preferable in terms of excellent heat resistance, moist heat resistance, durability, and transparency. Other monomers include, for example, methyl acrylate, methyl methacrylate, styrene, acrylonitrile, vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, hydroxylethyl acrylate, hydroxylethyl methacrylate, propylene glycol acrylate, acrylamide Methacrylamide, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, and n-ethylhexyl methacrylate. These can be used alone or in combination of two or more. In the present invention, among the other monomers, (meth) acrylic acid-n-butyl is preferable.

  The weight average molecular weight (Mw) of the acrylate copolymer used as the acrylic pressure-sensitive adhesive is preferably in the range of 800,000 to 2,000,000. When the weight average molecular weight is less than 800,000, the adhesive layer becomes soft and sufficiently follows the shrinkage amount of the TAC substrate, but cannot withstand internal stress repeated under high-temperature and high-humidity long-term conditions. When the molecular weight exceeds 2 million, the adhesive layer becomes hard, and the difference between the shrinkage amount of the TAC base material and the change amount of the adhesive layer becomes large, resulting in contraction stress. In each case, the contraction stress of the TAC base material is moderately relaxed. It is not preferable because it cannot be performed. The weight average molecular weight is a value in terms of polystyrene when measured by gel permeation chromatography (GPC).

  In addition, as a commercial item of the said acrylic adhesive, OC3949 (made by Seiden Chemical Co., Ltd.) etc. can be used suitably, for example. Here, OC3949 is an acrylic pressure-sensitive adhesive made of acrylic acid-n-butyl and ethyl acrylate.

[Curing agent]
In the said adhesion layer, it is preferable to use an isocyanate type hardening | curing agent as the hardening | curing agent from the reason that the adhesiveness to a TAC base material is favorable. Examples of the isocyanate curing agent include a polyisocyanate compound, a trimer of a polyisocyanate compound, a urethane prepolymer having a terminal isocyanate group obtained by reacting a polyisocyanate compound and a polyol compound, and 3 of the urethane prepolymer. Examples include a polymer. Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate, 2,5-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4′-diisocyanate, 3 -Methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, lysine isocyanate and the like.

  It is preferable that content of the said isocyanate hardening agent in the said adhesion layer is 0.2 to 1.0 mass part in conversion of solid content with respect to 100 mass parts of solid content of an acrylic adhesive. When the blending amount is less than 0.2 parts by mass, the elastic modulus at high temperature is lowered, so that sufficient stress relaxation properties are hardly exhibited and durability may not be obtained. On the other hand, when the content is more than 1.0 parts by mass, the elastic modulus increases, and it becomes difficult to follow the shrinkage of the adherend at a high temperature and the adhesive force is reduced, so that the float and peeling occur. It is not preferable in that it may be easy. If it is the said range, the adhesion layer which has moderate elasticity modulus can be formed, the contraction stress of a TAC base material is eased, and the adhesive film of a TAC base material is from an adherend even under high temperature and humidity. Can prevent floating.

[Acrylic copolymer]
In the above adhesive layer, the acrylic copolymer has improved adhesion to the TAC substrate at high temperature and the cohesiveness of the adhesive layer is improved, so that the elastic modulus at high temperature is difficult to decrease. It is preferable to use a block copolymer curing agent. The triblock copolymer consists of a methyl methacrylate polymer block (M) and a butyl acrylate polymer block (A), and the proportion of the butyl acrylate polymer block (A) is 70% by mass or more, The weight average molecular weight of the triblock copolymer is 10,000 to 300,000.

  Although it does not specifically limit as a triblock copolymer which satisfy | fills the said weight average molecular weight and the ratio for which a butyl acrylate polymer block (A) accounts, Specifically, for example, LA2330, LA2140, LA4285 (made by Kuraray) , M51, M52, M53, M52N, and M22N (manufactured by Arkema Co., Ltd.) can be suitably used.

  The blending amount of the acrylic copolymer is preferably 0.1 to 10 parts by mass, more preferably 1 to 3 parts by mass in terms of solid content with respect to 100 parts by mass of the solid content of the acrylic pressure-sensitive adhesive. . When the blending amount is less than 0.1 parts by mass, it is not preferable in that the elastic modulus at a high temperature is lowered and sufficient stress relaxation properties are hardly exhibited, and durability may not be obtained. On the other hand, when the content is more than 10 parts by mass, the compatibility with the acrylic pressure-sensitive adhesive is deteriorated, which is not preferable in that the transparency may be lowered. If it is the said range, it can prevent that the adhesive film of a TAC base material floats from a to-be-adhered body also on the conditions of hot and humid.

[Plasticizer]
It is more preferable to use a plasticizer in combination with the acrylic copolymer. By using the plasticizer in combination, it is possible to provide a laminate that can further prevent the TAC-based adhesive film from floating from the adherend even under high-temperature and high-humidity conditions. Examples of the plasticizer contained in the adhesive layer include phthalic acid ester compounds and adipic acid ester compounds.

  Examples of the phthalate ester plasticizer contained in the adhesive layer include di-2-ethylhexyl phthalate (DOP), dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and phthalic acid. Heptylnonyl (HNP), di-n-octyl phthalate (DNOP), di-i-octyl phthalate (DCapP), diisononyl phthalate (DINP), di-i-decyl phthalate (DIDP), ditridecyl phthalate (DTDP) ), Dicyclohexyl phthalate (DCHP), butyl benzyl phthalate (BDP), ethyl phthalyl ethyl glycolate (EPEG), butyl phthalyl butyl glycolate (BPBG), and the like. You may use together.

  Examples of the adipate plasticizer contained in the pressure-sensitive adhesive include dioctyl adipate (DOA), diisononyl adipate (DINA), diisodecyl adipate (DIDA), dimethyl adipate (DMA), and diethyl adipate ( DEA), diisopropyl adipate (DIPA), dipropyl adipate (DPA), diisobutyl adipate (DIBA), dibutyl adipate (DBA) and the like, and one or more of these may be used in combination.

  In the present invention, it is preferable to use an adipate ester plasticizer rather than a phthalate ester plasticizer from the viewpoint of an environmentally regulated substance. Of the adipate ester plasticizers, dioctyl adipate (DOA) is preferably used from the viewpoint of versatility and compatibility with resins.

  It is preferable that the compounding quantity of a plasticizer is 0.1-10 mass parts in conversion of solid content with respect to 100 mass parts of solid content of an acrylic adhesive, and it is more preferable that it is 1-7 mass parts. When the blending amount is less than 0.1 parts by mass, the elastic modulus of the obtained adhesive layer does not decrease, so the followability to the adherend that expands and contracts is insufficient, and floating or peeling from the adherend may occur. It is not preferable in terms. On the other hand, when the content is more than 10 parts by mass, the adhesive strength is greatly reduced, and it is not preferable in that floating and peeling easily occur. If it is the said range, even if it is under high temperature and humidity, it can prevent that the adhesive film of a TAC base material floats from a to-be-adhered body.

[Metal chelating agent]
In the pressure-sensitive adhesive layer, by using a metal chelating agent, after applying the pressure-sensitive adhesive to the base film, when drying to volatilize the solvent contained in the pressure-sensitive adhesive, the initial stage (before bonding the adherend) Is done. Examples of the metal chelating agent include titanium acetylacetonate, titanium octyl glycolate, titanium triethanolamate, tetra-n-butyl titanate, aluminum diisopropoxide monoethyl acetate, aluminum di-n-butoxide monomethyl acetoacetate, Aluminum di-i-butoxide monomethyl acetoacetate, aluminum di-n-butoxide monoethyl acetoacetate, aluminum di-sec-butoxide monoethyl acetoacetate, aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetonate), aluminum Mono-acetylacetonatobis (ethylacetoacetonate), zirconium acetylacetonate and acetylacetone zirconi Examples include umbutyrate. These are used alone or in combination of two or more.

  It is preferable that content of the said metal chelating agent in the said adhesion layer is 0.01-1 mass part in conversion of solid content with respect to 100 mass parts of solid content of an acrylic adhesive, 0.05-0.3 More preferably, it is part by mass. When the blending amount is less than 0.01 parts by mass, it is not preferable in that the elastic modulus at a high temperature is lowered and sufficient stress relaxation properties are hardly exhibited, and durability may not be obtained. On the other hand, when the content is more than 1 part by mass, the complex is formed with the ionic impurity in the adhesive layer or the adherend and yellows, which is not preferable in that the transparency may be lowered.

[Other additives]
Other additives are added as necessary to impart weather resistance, light resistance, heat resistance, moisture resistance, flame resistance, and the like to the adhesive layer. In addition, the additive is added as necessary to improve the stability, coating property, drying property, anti-blocking property and the like of the coating solution. As other additives, in particular, in addition to the above-mentioned pressure-sensitive adhesive, curing agent, acrylic copolymer, plasticizer and metal chelating agent, a silane coupling agent is used in combination and added, so that the TAC substrate and the adherend It is possible to further improve the adhesion to the object.

  Examples of the silane coupling agent include amino-based silane coupling agents such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-phenylaminofuropyltrimethoxysilane; ureido-based ureidopropyltriethoxysilane and the like. Silane coupling agents; vinyl silane coupling agents such as vinylethoxysilane, vinylmethoxysilane, vinyltris (β-methoxyethoxy) silane; methacrylates such as γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane Silane coupling agent; epoxy-based silane coupling agent such as γ-glycidoxypropyltrimethoxysilane; isocyanate-based silane coupling such as γ-isocyanatopropyltriethoxysilane Agent; Polymer type silane coupling agent such as polyethoxydimethylsiloxane and polyethoxydimethylsiloxane; Cationic silane coupling agent such as N- (N-benzyl-β-aminoethyl) -γ-aminopropyltrimethoxysilane hydrochloride Etc.

  Moreover, you may add a dispersing agent, an antifoamer, a light stabilizer, a ultraviolet absorber, a heat stabilizer, antioxidant. These can use a well-known thing without a restriction | limiting in particular, According to the performance calculated | required by a coating liquid or an adhesion layer, it selects suitably.

[Adhesive layer]
The thickness of the adhesive layer is usually 5 μm or more and 100 μm or less, preferably 15 μm or more and 40 μm or less. If the thickness is less than 5 μm, most of the adhesive layer follows the shrinkage of TAC, and the shrinkage stress of the TAC substrate cannot be relaxed. If it exceeds 100 μm, there is no problem with the stress relaxation property, but it may adversely affect optical properties such as light transmittance, which is not preferable.

  As for the viscosity of the adhesive layer, tan δ (60 ° C.) / Tan δ (20 ° C.), which is the ratio of the loss tangent at 60 ° C. to the loss tangent at 20 ° C., is 1.1 or more and less than 1.3. Preferably, tan δ (80 ° C.) / Tan δ (20 ° C.), which is the ratio of the loss tangent at 80 ° C. to the loss tangent at 20 ° C. of the adhesive layer, is 1.1 or more and less than 1.3. preferable. tan δ is one of the parameters that reflect the viscosity of the adhesive layer and show the stress relaxation behavior (deformation delay when force is applied). For example, tan δ is a dynamic viscoelasticity measurement method (attachment mode: compression mode, frequency) based on JIS K7244-1 using a solid viscoelasticity analyzer RSA-III manufactured by TA Instruments as a measuring device. 1 Hz, temperature: −50 to 150 ° C., temperature rise temperature: 5 ° C./min). The present invention prevents the adhesive film of the TAC base material from floating from the adherend even under high temperature and high humidity, and further prevents the end portion of the film from peeling off from the adherend even slightly. Therefore, the ratio of loss tangent tan δ at high temperature (60 ° C.) to loss tangent tan δ at room temperature (20 ° C.) was used as an index. When the ratio of tan δ is less than 1.1, the pressure-sensitive adhesive layer relaxes with respect to deformation of the TAC base material too quickly, and the TAC base material pressure-sensitive adhesive film may float from the adherend under high temperature and high humidity. It is not preferable. When the ratio of tan δ is 1.3 or more, the relaxation behavior of the pressure-sensitive adhesive layer with respect to deformation of the TAC base material is too slow. In this case, the adhesive film of the TAC base material may float from the adherend under high temperature and high humidity. This is not preferable.

  In addition to these, it is more preferable that tan δ (80 ° C.) is larger than tan δ (60 ° C.). If tan δ (80 ° C.) is smaller than tan δ (60 ° C.), the fluidity of the pressure-sensitive adhesive at high temperatures increases, and the stress applied to the deformation of the TAC substrate cannot be relaxed.

[Method for producing TAC laminate]
The method for producing the TAC laminate of the present invention is not particularly limited except for the preparation of the pressure-sensitive adhesive composition, and a conventionally known method can be used. As an example, it can be manufactured by laminating a TAC substrate on the surface on which the pressure-sensitive adhesive layer is formed on the release film after the entire surface of the pressure-sensitive adhesive composition is applied and dried by an applicator.

<Optical film>
By further forming a hard coat layer, an antireflection layer, etc. on the surface of the TAC laminate opposite to the adhesive layer of the TAC substrate, such as a liquid crystal display, plasma display, CRT display, EL display, field emission display, etc. In various image display devices, it can be suitably used as an optical film used for the purpose of antireflection, surface protection, antiglare and the like. The hard coat layer can be formed by a method of adding a cured film made of an acrylic UV curable resin to the surface of the TAC substrate. The antireflection layer can be formed by attaching fine particles such as silica.

<Optical member>
FIG. 1 shows an example of the configuration of the optical member 1 of the present invention. In the optical member 1 of the present invention, the TAC base material 11 and the polarizing plate 13 are bonded to each other on the one surface of the TAC base material 11 via the adhesive layer 12 and the polarizing plate is provided via the second adhesive layer 14. 13 and the glass base material 15 are stuck. Further, on the other surface of the TAC substrate 11, a hard coat layer 16 and an antireflection layer 17 are sequentially laminated. The pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition for TAC of the present invention corresponds to the pressure-sensitive adhesive layer 12 in FIG. A method for adhering the TAC substrate 11 and the polarizing plate 13 through the adhesive layer 12 is not particularly limited, but a pressure bonding method is usually used. In addition, the glass base material 15 tends to be thinned to about 0.5 mm in recent years, and the adhesive layer 12 of the present invention is suitably used when the thickness of the glass base material 15 is 0.1 mm to 0.7 mm. .

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

<Example 1>
100 parts by mass of an acrylic pressure-sensitive adhesive (trade name “OC3949”, weight average molecular weight: 1,200,000, solid content: 19.5%, manufactured by Seiden Chemical Co., Ltd.) and an isocyanate-based curing agent (trade name “K-130”, solid Min: 80%, made by Seiden Chemical Co., Ltd.) 0.05 parts by mass, silane coupling agent (trade name “S-1”, solid content: 6.3%, made by Seiden Chemical Co., Ltd.), 1 part by mass, and aluminum chelate 0.46 parts by mass of agent (trade name “M2”, solid content: 5%, manufactured by Seiden Chemical Co., Ltd.) and acrylic copolymer (trade name “LA2330”, solid content: 100%, methyl methacrylate polymer block (M) And a butyl acrylate polymer block (A) having a weight average molecular weight of 160,000 MAM type triblock copolymer (manufactured by Kuraray Co., Ltd.) is dissolved in toluene to give a solid content of 40%. Like 1.22 parts by mass of the prepared acrylic copolymer solution and 0.488 parts by mass of adipic ester plasticizer (trade name “DOA”, dioctyl adipate, solid content: 100%, manufactured by J-Plus), toluene and A pressure-sensitive adhesive composition was obtained by dissolving in 25 parts by mass of a mixed solvent of methyl ethyl ketone (trade name: KT-11, mass cost 1: 1, manufactured by DIC Graphics).

  A laminate of Example 1 was prepared using this pressure-sensitive adhesive composition. The laminate was produced using AR5.5 (Sony Chemical & Information Device), which is a commercially available optical film based on TAC. The configuration of AR5.5 is obtained by sequentially laminating a hard coat layer 16 and an antireflection layer 17 on one surface of the TAC substrate 11 as in the optical member 1 shown in FIG. Using the applicator, the pressure-sensitive adhesive composition has a pressure-sensitive adhesive layer thickness of 25 μm after being dried on a PET film (Toray Film Processing Co., Ltd., Therapy BX9A (RX) PET 38 μm) under a drying condition of 92 ° C. for 2 minutes. The surface of the release film on which the pressure-sensitive adhesive layer is formed is laminated on the surface opposite to the surface on which the antireflection layer 17 of AR5.5 is formed. The body was made. The thickness of the antireflection layer is 0.1 μm, the thickness of the hard coat layer is 10 μm, and the thickness of the TAC substrate is 80 μm.

  Moreover, the optical member of Example 1 was produced using the laminated body of Example 1. In the production of the optical member, a polarizing plate (product name “F1205DU”, manufactured by Nitto Denko Corporation) having a second adhesive layer different from the above adhesive layer on the surface, and a glass substrate (product name “Gorilla Glass # 1737”). ", Thickness: 0.7 mm, manufactured by Corning Co., Ltd."). Among the surfaces of the laminate of Example 1, the surface on which the adhesive layer is formed is the surface opposite to the surface on which the second adhesive layer is formed among the surfaces of the polarizing plate. Laminated. Subsequently, the surface of the polarizing plate on which the second adhesive layer was formed was laminated on a glass substrate. Thus, the optical member of Example 1 was produced.

<Example 2>
A laminate and an optical member of Example 2 were obtained in the same manner as in Example 1 except that the amount of the adipic acid ester plasticizer was 0.975 parts by mass.

<Example 3>
A laminate and an optical member of Example 3 were obtained in the same manner as in Example 1 except that the amount of the adipic acid ester plasticizer was 0.293 parts by mass.

<Example 4>
A laminate and an optical member of Example 2 were obtained in the same manner as in Example 1 except that the amount of the isocyanate curing agent was 0.1 parts by mass.

<Example 5>
The amount of the isocyanate curing agent was 0.1 parts by mass, and a phthalate ester plasticizer (trade name “DOP”, bis (2-ethylhexyl) phthalate) instead of the adipate ester plasticizer, A laminate and an optical member of Example 5 were obtained in the same manner as in Example 1 except that 0.975 parts by mass (solid content: 100%, manufactured by J-Plus) was used.

<Example 6>
Example 1 except that the amount of the isocyanate curing agent was 0.2 parts by mass and that 0.975 parts by mass of the phthalate ester plasticizer was used instead of the adipate ester plasticizer. By the same method, the laminated body and optical member of Example 6 were obtained.

<Example 7>
The lamination of Example 7 was carried out in the same manner as in Example 1 except that the amount of the isocyanate-based curing agent was 0.2 parts by mass and the aluminum chelating agent and the adipic acid ester-based plasticizer were not added. A body and an optical member were obtained.

<Example 8>
The amount of the isocyanate curing agent was 0.2 parts by mass, the aluminum chelating agent was not added, and 0.975 parts by mass of the phthalate ester plasticizer was used instead of the adipic ester plasticizer. A laminated body and an optical member of Example 8 were obtained in the same manner as in Example 1 except for that.

<Example 9>
The laminated body and optical member of Example 9 were prepared in the same manner as in Example 1 except that the amount of the isocyanate curing agent was 0.2 parts by mass and the adipate ester plasticizer was not added. Obtained.

<Comparative Example 1>
The laminate of Comparative Example 1 was prepared in the same manner as in Example 1 except that the amount of the isocyanate curing agent was 0.2 parts by mass, and the acrylic copolymer and the adipic acid ester plasticizer were not added. And the optical member was obtained.

<Comparative Example 2>
The amount of the isocyanate curing agent was 0.2 parts by mass, the aluminum chelating agent and the acrylic copolymer were not added, and the phthalate ester plasticizer 0.975 instead of the adipate ester plasticizer. A laminate and an optical member of Comparative Example 2 were obtained in the same manner as in Example 1 except that the parts by mass were used.

<Comparative Example 3>
The amount of the isocyanate curing agent was 0.2 parts by mass, the acrylic copolymer was not added, and 0.975 parts by mass of the phthalate ester plasticizer was used instead of the adipic ester plasticizer. Except for this, a laminate and an optical member of Comparative Example 3 were obtained in the same manner as in Example 1.

<Comparative example 4>
A laminate and an optical member of Comparative Example 4 were obtained in the same manner as in Example 1 except that the aluminum chelating agent and the adipic acid ester plasticizer were not dissolved.

<Comparative Example 5>
Example 1 except that the amount of the isocyanate curing agent was 0.3 parts by mass, and 0.975 parts by mass of the phthalate ester plasticizer was used instead of the adipate ester plasticizer. By the same method, the laminated body and optical member of the comparative example 5 were obtained.

<Comparative Example 6>
In place of the acrylic pressure-sensitive adhesive, 100 parts by mass of an acrylic pressure-sensitive adhesive (trade name “EG-655”, weight average molecular weight: 1 million, solid content: 23.5%, manufactured by Toyochem Co., Ltd.) is used, and the isocyanate-based curing is performed. 0.02 parts by mass of an isocyanate curing agent (trade name “BXX5627”, solid content: 50%, manufactured by Toyochem Co., Ltd.) is used instead of the agent, and the silane coupling agent, the aluminum chelating agent, the acrylic copolymer, and the adipine. A laminate and an optical member of Comparative Example 6 were obtained in the same manner as in Example 1 except that the acid ester plasticizer was not added.

<Comparative Example 7>
Instead of the above acrylic adhesive, 100 parts by mass of an acrylic adhesive (trade name “SK1811L”, weight average molecular weight: 600,000, solid content: 23%, manufactured by Soken Chemical Co., Ltd.) is used instead of the above isocyanate curing agent. In addition, 0.4 parts by mass of an isocyanate curing agent (trade name “TD-75”, solid content: 75%, manufactured by Soken Chemical Co., Ltd.) was used instead of the silane coupling agent (trade name “A” -50 ", solid content: 50%, manufactured by Soken Chemical Co., Ltd.) Example 1 except that 0.4 parts by mass was used and the aluminum chelating agent, the acrylic copolymer and the adipic acid ester plasticizer were not added. By the same method, the laminated body and optical member of the comparative example 7 were obtained.

<Comparative Example 8>
In place of the acrylic pressure-sensitive adhesive, 100 parts by weight of an acrylic pressure-sensitive adhesive (trade name “SK2403”, weight average molecular weight: 500,000, solid content: 29.3%, manufactured by Soken Chemical Co., Ltd.) is used. Instead of 7.7 parts by mass of an isocyanate-based curing agent (trade name “L-45”, solid content: 45%, manufactured by Soken Chemical Co., Ltd.), the silane coupling agent, the aluminum chelating agent, the acrylic copolymer, and A laminate and an optical member of Comparative Example 8 were obtained in the same manner as in Example 1 except that the adipic acid ester plasticizer was not added.

<Comparative Example 9>
In place of the acrylic pressure-sensitive adhesive, 100 parts by weight of an acrylic pressure-sensitive adhesive (trade name “SK2403”, weight average molecular weight: 500,000, solid content: 29.3%, manufactured by Soken Chemical Co., Ltd.) is used. Instead of 7.7 parts by mass of an isocyanate curing agent (trade name “L-45”, solid content: 45%, manufactured by Soken Chemical Co., Ltd.), and phthalate ester plasticity instead of the adipate ester plasticizer. 2.93 parts by mass of an agent (trade name “DINP”, diisononyl phthalate), solid content: 100%, manufactured by J-Plus Co., Ltd., and the silane coupling agent, the aluminum chelating agent, and the acrylic copolymer were not added. Except for this, a laminate and an optical member of Comparative Example 9 were obtained in the same manner as in Example 1.

<Examination of stress relaxation characteristics>
By performing the following tests, the stress relaxation characteristics of the TAC laminate of the present invention were verified from the viscoelasticity side of the adhesive layer.

  Using the laminates of the examples and comparative examples, the loss tangent tan δ at room temperature (20 ° C.) and the loss at the first high temperature state (60 ° C.) for the adhesive layers of the examples and comparative examples The tangent tan δ and the loss tangent tan δ at the second high temperature state (80 ° C.) were measured. Then, (I) the ratio of tan δ at the first high temperature state to tan δ at the room temperature state tan δ (60 ° C.) / Tan δ (20 ° C.), and (II) the tan δ at the second high temperature state in the room temperature state. The ratio of tan δ (80 ° C.) / tan δ (20 ° C.) to tan δ and (III) tan δ in the second high temperature state and tan δ in the first high temperature state tan δ (80 ° C.) − tan δ (60 ° C.) And calculated. The loss tangent tan δ is measured using a dynamic viscoelasticity measurement method (attachment mode: compression mode, frequency: 1 Hz) according to JIS K7244-1 using a solid viscoelasticity analyzer RSA-III manufactured by TA Instruments. (Temperature: -50 to 150 degrees, temperature increase rate: 5 degrees / minute). Table 3 shows the measurement results. For the above (I) and (II), the case where the ratio of tan δ was 1.1 or more and less than 1.3 was set as “◯”, and the case where it was not so was set as “X”. For (III) above, the case where the difference in tan δ is 0 or more is “◯”, and the case where it is not is “X”.

<Evaluation of durability test>
Each optical member of each example and comparative example was stored for 500 hours under conditions of high temperature and high humidity (60 ° C., 90% RH), and then visually measured whether the adhesive film of the TAC substrate was lifted from the polarizing plate. did. The evaluation criteria are as follows.
○: Lifting or peeling occurred.
X: No lifting or peeling occurred.
Table 3 shows the measurement results.

  The pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive, an isocyanate-based curing agent, and an acrylic copolymer, and both tan δ (60 ° C.) / Tan δ (20 ° C.) and tan δ (80 ° C.) / Tan δ (20 ° C.) Is not less than 1.1 and less than 1.3, and the optical member using the TAC laminate in which the difference in tan δ is not less than 0 can appropriately relieve the shrinkage stress of the TAC substrate. It was confirmed that the film can be prevented from floating from the polarizing plate (Examples 1 to 9).

On the other hand, when the adhesive layer does not contain an acrylic copolymer, the loss tangent at 60 ° C. is higher than the loss tangent at 80 ° C. even if a metal chelating agent is added. As a result, it was found that the fluidity of the pressure-sensitive adhesive at a high temperature increases and the stress applied to the deformation of the TAC substrate may not be sufficiently relaxed. (Comparative Example 1).
When the adhesive layer does not contain an acrylic copolymer, the value of tan δ (80 ° C.) / Tan δ (20 ° C.) is greater than 1.3 regardless of the presence or absence of the phthalate ester plasticizer, and the TAC substrate Since the relaxation behavior of the pressure-sensitive adhesive layer against the deformation of the TAC was too slow, it was found that the TAC-based pressure-sensitive adhesive film might float from the polarizing plate under high temperature and high humidity (Comparative Examples 2 and 4).
In the case where the adhesive layer does not contain an acrylic copolymer, the value of tan δ (60 ° C.) / Tan δ (20 ° C.), tan δ ( 80 ° C.) / Tan δ (20 ° C.) are both smaller than 1.1, and the relaxation behavior of the adhesive layer against deformation of the TAC substrate is too fast. It was found that there is a possibility of floating from the polarizing plate (Comparative Example 3).

Moreover, even if the addition amount of isocyanate hardening agent exceeds 1.0 mass part in conversion of solid content with respect to 100 mass parts of solid content of acrylic adhesive, even if the adhesion layer contains the acrylic copolymer, Since the relaxation behavior of the pressure-sensitive adhesive layer with respect to the deformation of the TAC base material is too fast, it was found that the adhesive film of the TAC base material may float from the polarizing plate under high temperature and high humidity (Comparative Example 5).
Further, when the weight average molecular weight of the acrylic pressure-sensitive adhesive is 800,000 or less, since the relaxation behavior of the pressure-sensitive adhesive layer against deformation of the TAC base material is too fast, the pressure-sensitive adhesive film of the TAC base material floats from the polarizing plate under high temperature and high humidity. It was found that there was a possibility (Comparative Examples 6 to 9).

DESCRIPTION OF SYMBOLS 1 Optical member 11 TAC base material 12 Adhesive layer 13 Polarizing plate 14 2nd adhesive layer 15 Glass base material 16 Hard-coat layer 17 Antireflection layer

Claims (8)

A laminate in which an adhesive layer is formed on a triacetyl cellulose substrate,
The adhesive layer is
An acrylic pressure-sensitive adhesive having a weight average molecular weight of 800,000 to 2,000,000 ,
An isocyanate curing agent that is 0.2 parts by mass or more and 1.0 part by mass or less in terms of solid content with respect to 100 parts by mass of solid content of the acrylic adhesive ,
An acrylic block copolymer having a weight average molecular weight of 10,000 or more and 300,000 or less and 0.1 to 10 parts by mass in terms of solid content with respect to 100 parts by mass of the solid content of the acrylic pressure-sensitive adhesive. Contains a laminate. 2. The laminate according to claim 1, wherein tan δ (60 ° C.) / Tan δ (20 ° C.), which is a ratio of loss tangent at 60 ° C. to loss tangent at 20 ° C., of the adhesive layer is 1.1 or more and less than 1.3. body. The laminate according to claim 1 or 2 , wherein the acrylic block copolymer comprises a methacrylic acid ester polymer block and an acrylic acid ester polymer block. The acrylic block copolymer is a MAM type triblock copolymer having a weight average molecular weight of 10,000 to 300,000 consisting of a methyl methacrylate polymer block (M) and a butyl acrylate polymer block (A). The laminate according to claim 1 or 2 , which is a polymer. The laminate according to any one of claims 1 to 4 , wherein the pressure-sensitive adhesive layer has a thickness of 5 µm or more and 100 µm or less. The laminate according to any one of claims 1 to 5 , wherein the adhesive layer further contains an adipate ester plasticizer or a phthalate ester plasticizer. The optical film by which the hard-coat layer and the antireflection layer were formed in the surface on the opposite side to the said adhesion layer of the said triacetyl cellulose base material in the laminated body in any one of Claim 1 to 6 . The optical member by which the said triacetyl cellulose base material and a polarizing plate are laminated | stacked through the said adhesion layer in the optical film of Claim 7 .

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