TW201443469A - Laminate capable of restraining occurrence of iridescence, sheet capable of restraining occurrence of iridescence and method for restraining occurrence of iridescence - Google Patents

Abstract

The present invention reduces the occurrence of rainbow unevenness in a laminate having a hardcoat layer and a transparent substrate layer layered with a simple adhesive layer interposed therebetween. This laminate (1) has a structure in which the following are layered, in order: a hardcoat layer (10), a simple adhesive layer (11), a transparent substrate layer (12), and a functional layer (13) containing an ultraviolet-absorbing agent and an adhesive.

Description

Reducing the occurrence of rainbow spots, reducing the occurrence of rainbow spots, and reducing the occurrence of rainbow spots

The present invention relates to a laminate which reduces the occurrence of rainbow spots of a hard coat film. Specifically, the present invention relates to a laminate having a structure in which a hard coat layer, an easy-adhesion layer, a transparent substrate layer, and a functional layer containing an ultraviolet absorber and an adhesive are sequentially laminated. Further, the present invention relates to a method for reducing the occurrence of a rainbow spot occurring in a hard coat film, and a method for reducing the occurrence of a rainbow spot of a hard coat film.

In order to prevent damage or the like, a flat panel display, a touch panel, an electromagnetic wave shielding material, and the like are provided with a hard coat film in which a hard coat layer and a transparent base material are laminated in an easy-to-adhere layer. The hard coat film is generally used by bonding an adhesive sheet to another member such as an optical member. For example, it is used in combination with an optical member such as a liquid crystal panel, a front panel, or an antireflection body. Hard coat films in combination with these are used in various products. Its use or use is varied, and it is also used for long-term use in outdoor conditions such as high temperature and humidity. Therefore, the hard coat film is required to exhibit good performance and sustainable use even when placed in various use cases.

Previously, regarding a hard coat film having a hard coat layer and a transparent base material layer, it has been known that interference fringes are generated due to the fact that each layer has a different refractive index. In order to reduce this problem, An easy-adhesion layer serving as an intermediate layer is disposed between the hard coat layer and the transparent substrate layer. For example, as disclosed in Patent Document 1, the generation of interference fringes is reduced by providing an easy-adhesion layer having an intermediate refractive index of a refractive index of a hard coat layer and a refractive index of a transparent base material layer.

Further, in Patent Document 2, it is proposed to insert two or more easy-adhesion layers between the hard coat layer and the transparent base material layer. Thereby, the fluctuation amplitude of the reflectance of the hard coat surface can be suppressed, and the generation of interference fringes can be reduced. In Patent Document 2, by inserting two or more layers of the easy-to-layer layer, the difference in refractive index between the layers can be reduced, and a sufficient effect of suppressing interference fringes can be obtained.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-177209

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2012-35560

By providing an easy-adhesion layer between the hard coat layer and the transparent base material layer as described above, the difference in refractive index between the hard coat layer and the transparent base material layer can be reduced, and generation of interference fringes can be suppressed.

However, according to the research by the inventors of the present invention, the hard coating film is discolored if the product of the laminate disclosed in Patent Document 1 and Patent Document 2 is used for a long period of time under an excessively harsh condition such as outdoors or under high humidity. , so that rainbow spots occur. The rainbow spots that occur in the hard coat film can significantly reduce the display function of the display, which is a problem.

Therefore, the inventors of the present invention have advanced the research in order to solve the problems of the prior art and to obtain a laminate which does not cause rainbow spots in the hard coat film even under long-term use under too severe conditions.

In order to solve the above problems, in order to prevent rainbow spots from occurring in a hard coating film even under long-term use under severe conditions, the inventors of the present invention have a novel idea of laminating functional layers on a hard coating film instead of making it easy to proceed. The idea of optimizing the layer or hard coat is studied. result The present inventors have found that by sequentially laminating a hard coat layer, an easy-adhesion layer, a transparent substrate layer, and a functional layer containing an ultraviolet absorber and an adhesive, rainbow spots can be reduced in the hard coat film, thereby The present invention has been completed. That is, the present invention suppresses the occurrence of rainbow spots by laminating a functional layer containing an ultraviolet absorber and an adhesive in a specific arrangement, and suppresses the occurrence of rainbow spots by laminating a functional layer on the hard coat film.

The present invention provides the following invention as a technical means for solving the problem.

[1] A laminate having a structure in which a hard coat layer, an easy-adhesion layer, a transparent base material layer, and a functional layer containing an ultraviolet absorber and an adhesive are sequentially laminated.

[2] The laminate according to [1], wherein the hard coat layer is a layer containing an acrylic resin and has a thickness of 0.5 to 20 μm.

[3] The laminate according to [1] or [2], wherein the transparent base material layer is a layer containing a polyester resin and has a thickness of 10 to 300 μm.

[4] The laminate according to any one of [1] to [3] wherein the easy-adhesion layer is a layer containing an acrylic resin or a polyester resin and has a thickness of 0.1 nm to 1 μm.

[5] The laminate according to any one of [1] to [4] wherein the above-mentioned easy-to-adhere layer is formed of a single layer.

[6] The laminate according to any one of [1] to [5] wherein the functional layer has a UV transmittance of less than 5% at a wavelength of 340 nm.

[7] The laminate according to any one of [1] to [6] wherein the ultraviolet absorber contains at least one compound which is oily or liquid at 23 ° C, and is solid relative to the functional layer. The component is contained in an amount of 0.5 to 8 parts by mass based on 100 parts by mass.

[8] The laminate according to any one of [1] to [7] wherein the functional layer contains at least two kinds of ultraviolet absorbers.

[9] The laminate according to any one of [1] to [8] wherein the functional layer contains a benzotriazole-based ultraviolet absorber and three It is a UV absorber.

[10] The laminate according to claim 9, wherein the functional layer contains the benzotriazole-based ultraviolet absorber and the above three in a mass ratio of 1:1 to 1:3. It is a UV absorber.

[11] The laminate according to any one of [1] to [10] wherein the functional layer further has a release layer.

[12] The laminate according to any one of [1] to [11] wherein the functional layer further has a member.

[13] The laminate according to [12], wherein the member is glass.

[14] A sheet for reducing rainbow incidence, which is characterized in that it has a hard coating layer, a hard coating layer, and a hard coating film of a transparent substrate layer, and contains a UV absorbing agent. And adhesives.

[15] A method for reducing rainbow ray generation, characterized in that: the method further comprises a hard coat layer, an easy adhesion layer, and a hard coating film of a transparent substrate layer, wherein the rainbow ray generation method is performed, and the transparent layer of the layer is On the side of the material layer, a functional layer containing a UV absorber and an adhesive layer is laminated.

According to the present invention, it is possible to provide a laminate in which a rainbow spot does not occur in a hard coat film even under an excessively harsh condition such as high temperature and high humidity. Moreover, by attaching the reduced rainbow spot generating sheet of the present invention to a hard coating film having a hard coating layer, an easy adhesion layer, and a transparent substrate layer in sequence, the rainbow spot of the hard coating film can be effectively suppressed. occur. Further, according to the method for reducing rainbow ray generation of the present invention, the occurrence of a rainbow spot of a hard coat film having a hard coat layer, an easy adhesion layer, and a transparent substrate layer in this order can be reduced by a simple method.

1‧‧ ‧ laminated body

10‧‧‧hard coating

11‧‧‧Easy layer

12‧‧‧Transparent substrate layer

13‧‧‧ functional layer

Fig. 1 is a schematic cross-sectional view showing the structure of a laminated body of the present invention.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below is based on a representative embodiment or a specific example of the present invention, but the present invention It is not limited to such an embodiment or a specific example. In the present specification, the numerical range expressed by "~" means a range in which the numerical value described before and after "~" is used as the lower limit and the upper limit.

[layered body]

<Characteristics of composition>

The laminated body 1 of the present invention has a structure in which a hard coat layer 10, an easy-adhesion layer 11, a transparent base material layer 12, and a functional layer 13 containing an ultraviolet absorber and an adhesive are sequentially laminated. Thereby, even when it is used for a long period of time under conditions of excessively high temperature and humidity, it is possible to suppress occurrence of rainbow spots in the hard coat film. Further, the term "laser" in the present invention means that birefringence interference occurs in the hard coat film, and the hard coat film is discolored due to the birefringence interference color.

An example of the laminated body 1 of the present invention is shown in Fig. 1 . In FIG. 1, the hard coat layer 10, the easy-adhesion layer 11, the transparent base material layer 12, and the functional layer 13 are each adjacent to each other and directly bonded.

Hereinafter, the hard coat layer, the easy-adhesion layer, the transparent base material layer, and the functional layer constituting the laminate of the present invention will be described in detail in order.

<hard coating>

The laminate of the present invention has a hard coat layer. The laminate preferably has visible light transmittance, and therefore it is preferred that the hard coat layer be transparent. Regarding the hard coat layer, it is preferred that the hardness is high to prevent damage on the surface of the laminate. The center line average roughness of the hard coat layer defined by JIS B 0601 is preferably from 1 to 20 nm, more preferably 10 nm or less. The center line average roughness can be measured, for example, using an ultra-depth shape measuring microscope manufactured by Keynes Co., Ltd., or the like.

The hard coat layer contains a hard component for imparting hardness, and the hard component has a crosslinked polymer as a main component. Examples of the crosslinked polymer contained in the hard coat layer include a monofunctional monomer polymer and a polyfunctional monomer polymer. The polyfunctional monomer polymer is preferably a polymer of a polymerizable monomer containing a trifunctional or higher polyfunctional monomer, more preferably a polymer of a polymerizable monomer containing a polyfunctional monomer having 4 or more functional groups. For example, it is also preferable to exemplify more than three functional groups A copolymer of a mixed monomer of a functional monomer and a bifunctional monomer, or the like. Furthermore, oligomers are also included in the monomers described herein.

The kind of the monomer which can be used for obtaining the crosslinked polymer is not particularly limited, and for example, an acrylic monomer or the like can be preferably exemplified. For example, dipropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol (mass average molecular weight 600) 2 (Meth) acrylate, propylene oxide modified neopentyl glycol di(meth) acrylate, modified bisphenol A di(meth) acrylate, tricyclodecane dimethanol di(meth) acrylate a bifunctional (meth) acrylate such as polyethylene glycol (mass average molecular weight 400) di(meth) acrylate, pentaerythritol tri(meth) acrylate, trimethylolpropane tri (meth) acrylate, Trifunctional (meth) acrylate such as trimethylolpropane ethoxy tris(meth) acrylate, polyether tri(meth) acrylate, glyceryl propoxy tri(meth) acrylate, pentaerythritol tetra ( Methyl) acrylate, pentaerythritol ethoxy tetra(meth) acrylate, di-trimethylolpropane tetra(meth) acrylate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol A tetrafunctional or higher (meth) acrylate such as hydroxypenta(meth)acrylate or dipentaerythritol hexa(meth)acrylate.

The monomer or oligomer of the organic compound having a polymerizable unsaturated group may be thermosetting or active energy ray hardenability.

In addition, the "(meth)acrylic acid" of the present invention is a general term for acrylic acid and methacrylic acid.

The hard coat layer may also contain a softening component. When a soft component contains a soft component, cracking can be prevented. Examples of the softening component include tricyclodecane hydroxymethyl bis (meth) acrylate, ethylene oxide modified di(meth) acrylate of bisphenol F, and ethylene oxide of bisphenol A. Modified di(meth)acrylate, isophthalic acid modified ethylene oxide di(meth)acrylate, polypropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylic acid 2-functional (meth) acrylate such as ester, trimethylolpropane tri(meth) acrylate, propylene oxide modified tri(meth) acrylate of trimethyl propane, epoxy B of trimethyl propane alkyl A trifunctional (meth) acrylate such as a modified tri(meth)acrylate, a (meth)acrylic acid urethane, a polyester (meth) acrylate, or a polyether (meth) acrylate.

Further, the crosslinked polymer may contain inorganic particles and/or organic particles. When inorganic particles and/or organic particles are contained, it is preferable in terms of suppressing hardening shrinkage of a coating film. Examples of the inorganic particles include inorganic oxide particles such as cerium oxide particles, titanium oxide particles, zirconia particles, alumina particles, tin dioxide particles, cerium pentoxide particles, and antimony trioxide particles. Further, examples of the organic particles include resin particles such as acrylic resin, polystyrene, polyoxyalkylene, melamine resin, benzoguanamine resin, polytetrafluoroethylene, cellulose acetate, polycarbonate, and polyamide. .

In the case of using inorganic particles, reactive inorganic oxide particles treated with a coupling agent may also be used. In the case of using organic particles, reactive organic oxide particles treated with a coupling agent can also be used. The bonding force with the acrylic polymer can be improved by treatment with a coupling agent. As a result, the surface hardness or the scratch resistance can be improved, and the dispersibility of the inorganic oxide particles and the organic particles can be improved.

Examples of the coupling agent include γ-aminopropyltriethoxydecane, γ-aminopropyltrimethoxydecane, γ-glycidoxypropyltriethoxysilane, and γ-glycidyloxygen. Propyltrimethoxydecane, γ-mercaptopropyltrimethoxydecane, γ-aminopropyltriethoxydecane, γ-aminopropyltriethoxyaluminum, and the like. These may be used alone or in combination of two or more. The amount of the coupling agent to be treated is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of the inorganic oxide particles or the organic particles.

The thickness of the hard coat layer constituting the laminate of the present invention is not particularly limited, and may be, for example, 0.5 μm or more, and may be selected from the range of 1.0 μm or more and 2.0 μm or more. The upper limit varies depending on the application, and may be selected, for example, within a range of 1 mm or less, 50 μm or less, or 20 μm or less.

<easy layer>

The easy-adhesive layer constituting the laminate of the present invention contains an acrylic resin or a polyester tree fat. Further, a urethane-based resin or the like may be contained as needed.

The acrylic resin used in the easy-adhesion layer of the present invention can be exemplified by polymerization of an acrylic monomer as shown below. For example, an alkyl acrylate or an alkyl methacrylate having a linear, branched or cyclic alkyl group, a hydroxyl group-containing monomer, an epoxy group-containing monomer, and a guanamine-containing group may be mentioned. Monomers, etc., but are not limited to these. Further, these monomer components may be copolymerized using two or more kinds.

Moreover, as a polyester type resin, the polyhydric acid component and the polyol component are aggregated and condensed. Examples of the polybasic acid to be used include terephthalic acid, isophthalic acid, and diphenylcarboxylic acid. Examples of the polyol component include ethylene glycol and diethylene glycol, but are not limited thereto. Further, these monomer components may be copolymerized using two or more kinds.

The urethane-based resin can be exemplified by a reaction product of a polyol compound and an isocyanate compound. Examples of the polyol compound to be used include a polyester polyol, a polyether diol, and a polyacetal diol. Examples of the isocyanate compound include toluene diisocyanate and benzene diisocyanate, but are not limited thereto. Further, these components may be reacted in two or more kinds. Further, if necessary, a chain length extender, a crosslinking agent, or the like may be used.

For the easy-adhesion layer constituting the laminate of the present invention, particles may be added to impart slipperiness or to adjust the refractive index. Examples of the particles include an inorganic pigment, an organic filler, and the like. In order to obtain a high transparency in order to obtain a relatively high refractive index with respect to the resin of the easy-adhesion layer, it is preferred to use cerium oxide. Further, examples of the particles used for the purpose of adjusting the refractive index of the easy-adhesion layer include an alumina-yttria composite, titanium oxide, zirconium oxide, zinc oxide, and the like, but are not limited thereto. Further, two or more kinds of these particles may be used.

For the easy-adhesive layer constituting the laminate of the present invention, various additives such as an antistatic agent, an ultraviolet absorber, and a plasticizer may be added as needed. Further, a surfactant or a pH adjuster may be added to improve coating suitability or reactivity.

The thickness of the easy-adhesion layer constituting the laminate of the present invention is not particularly limited, and for example, The thickness is set to 0.1 nm or more, and may be selected from the range of 1 nm or more and 5 nm or more. The upper limit may vary depending on the application, and may be selected, for example, within a range of 1 μm or less, 100 nm or less, or 50 nm or less.

The method for forming the easy-adhesion layer in the present invention is not particularly limited. When a polyester-based resin is used as the transparent base material layer, it is preferred to melt-extrude the polyester-based resin onto the polyester-based resin sheet. Form an easy adhesion layer. The polyester resin sheet is melted and extruded, and then stretched in the longitudinal direction by 3 to 10 times to form a longitudinally stretched polyester resin film, and subjected to corona discharge treatment as needed. An easy-adhesion layer is applied to at least one of the faces and dried to form an easy-adhesion layer. Thereafter, by extending the film having the easy-adhesion layer by 3 to 10 times in the lateral direction, an easy-adhesion layer extending in the lateral direction is simultaneously formed when the biaxially stretched polyester resin film is formed.

Further, as another method, the polyester resin and the resin for easy adhesion layer may be simultaneously extruded to form a laminated film, and the laminated film may be biaxially stretched to 9 to 100 times by a known method to form an easy-adhesion layer. .

The film produced as described above may be subjected to surface treatment in a haze of not more than 8% by a known method such as corona discharge treatment or flame treatment, as needed.

<Transparent substrate layer>

The laminate of the present invention has a transparent substrate layer. The transparent substrate layer is a transparent material that transmits visible light and contains a film-like material. Typical constituent materials are transparent resins, and examples thereof include polyethylene terephthalate (PET) film, polyethylene naphthalate film, polytrimethylene terephthalate film, and poly (terephthalic acid). Butadiene ester film, propylene naphthalate film, polyethylene film, polypropylene film, celecoxib, diethyl phthalocyanine film, triethylene fluorene cellulose film, acetonitrile cellulose butyrate film, poly Vinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polyfluorene film, polyetheretherketone A film, a polyether ruthenium film, a polyether phthalimide film, a polyimide film, a fluororesin film, a polyamide film, an acrylic resin film, or the like. Among these, excellent heat resistance In a heterogeneous aspect, a polyethylene terephthalate (PET) film can be preferably used.

The transparent substrate layer constituting the laminate of the present invention may be a single layer or a plurality of layers. In the case where a plurality of layers are included, the transparent substrate layer may also contain different polyester resins.

The thickness of the transparent base material layer constituting the laminate of the present invention is not particularly limited, and may be, for example, 10 μm or more, and may be selected from the range of 20 μm or more and 50 μm or more. The upper limit varies depending on the application, and may be selected, for example, within a range of 1 cm or less, 1 mm or less, or 300 μm or less.

<functional layer>

The laminate of the present invention has a functional layer. The functional layer is a layer containing an ultraviolet absorber and an adhesive. The functional layer functions to bond a layer having a transparent base material layer and a hard coat layer which are laminated with an easy-to-adhere layer to other members.

(1) Adhesive layer of functional layer

As the adhesive, an acrylic polymer is preferably exemplified. Among them, a copolymer in which a (meth)acrylic acid-based monomer having a functional group is copolymerized with a (meth)acrylic acid alkyl ester having no functional group as a main component is preferably used. The (meth)acrylic monomer having a functional group serves as a reaction point in the case of using a crosslinking agent, and the adhesion, cohesive force, and heat resistance can be controlled by crosslinking. The amount of the (meth)acrylic monomer having a functional group other than the (meth)acrylic acid alkyl ester and the (meth)acrylic alkyl ester having no functional group, so as to constitute all the copolymers The ratio of the body mass is preferably 0.01 to 20% by mass. More preferably, it is 0.1 to 15% by mass, and further preferably 0.5 to 10% by mass.

Examples of the monomer constituting the acrylic polymer having no functional group (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid. Ester, butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, (A) a (meth)acrylic acid alkyl ester monomer such as isodecyl acrylate or lauryl (meth)acrylate, Two or more types may be used in combination as needed.

Moreover, examples of the (meth)acrylic monomer having a functional group include (meth)acrylic acid, maleic acid, maleic anhydride, methylene succinic acid, and fumaric acid. a carboxyl group-containing monomer such as fumaric anhydride, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, polyethylene glycol ( a hydroxyl group-containing monomer such as methyl acrylate, (meth) acrylamide, morpholinyl acrylamide, N,N-dimethylaminoethyl acrylate, N-tert-butylaminoethyl acrylate An epoxy group such as an amino group-containing (meth) acrylate or a glycidyl (meth) acrylate may be used in combination of two or more kinds as needed.

When the adhesive is polymerized, for example, a solution polymerization method can be applied. Examples of the solution polymerization method include an ion polymerization method and a radical polymerization method. Examples of the solvent to be used in this case include tetrahydrofuran, chloroform, ethyl acetate, toluene, hexane, acetone, and methyl ethyl ketone.

In the present invention, a solution polymerization method using an organic solvent or an active energy ray-curing type adhesive is preferably used.

When the adhesive used in the present invention is a copolymer using a monomer having a functional group, the crosslinking treatment can be carried out by blending a crosslinking agent.

Examples of the crosslinking agent include an isocyanate compound and an epoxy compound. An oxazoline compound, an aziridine compound, a metal chelate compound, a butylated melamine compound, or the like may be used in combination of two or more kinds as needed.

Among these crosslinking agents, an isocyanate compound or an epoxy compound is preferred from the viewpoint of easily crosslinking the acrylic polymer. Examples of the isocyanate compound include toluene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol diglycidyl ether, and neopentyl glycol. Glycidyl ether, 1,6-hexanediol diglycidyl ether, tetraglycidyl xylene diamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, trimethylolpropane polycondensation Glycerol ether, diglycerin polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, and the like.

The content of the crosslinking agent is preferably appropriately selected depending on the desired adhesive properties.

(2) Functional layer of ultraviolet absorber

The ultraviolet absorber for the functional layer can be selected from those having the largest absorption wavelength in the ultraviolet range. In the present invention, it is particularly preferred to use an ultraviolet absorber having a maximum absorption wavelength of 350 nm or more. The ultraviolet absorber having a maximum absorption wavelength at a wavelength of 350 nm or more is, for example, a compound represented by the following formula (1) or (2).

In the above formula, R ¹ represents a hydrogen atom, a halogen atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group or a cyano group, R ² represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group. Structure.

In the above formula, R ⁴ , R ⁵ and R ⁶ are a hydrogen atom, a hydroxyl group, an alkyl group structure or a halogen atom, and not all of R ⁴ , R ⁵ and R ⁶ are a hydrogen atom.

The alkyl-based structure is a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkoxy group, and the like is an alkyl group and contains a substituent.

Among them, a UV absorber which exhibits compatibility in a liquid crystal having a large molecular weight by introducing an alkyl group having a large molecular weight into an aromatic ring of the basic skeleton and exhibiting a liquid or oil form at 23 ° C can be preferably used. Here, the term "liquid or oil" is used at 23 ° C, meaning that it has a fluidity state even in the case of a UV absorber without a dilution solvent.

The content of the ultraviolet absorber of the present invention is preferably from 0.5 to 8 parts by mass, more preferably from 0.5 to 8 parts by mass, even more preferably from 100 to 8 parts by mass, based on 100 parts by mass of the solid content component (especially the acrylic polymer) of the functional layer. 0.5 to 6 parts by mass, preferably 1 to 3 parts by mass. The content of the ultraviolet absorber of the present invention is preferably adjusted so that the ultraviolet transmittance at 340 nm becomes less than 5%. When the content is at least the above lower limit value, when the thickness of the functional layer is 25 μm, the transmittance of light having a wavelength of 340 nm is effectively lowered, so that the effect of the present invention can be more easily obtained. In addition, as long as it is at most the above-mentioned upper limit, the adhesive property is not impaired. Therefore, it is preferably 1 to 6 parts by mass, and a transmittance of 2% or less can be obtained more stably.

The functional layer preferably contains at least two ultraviolet absorbers. Here, two kinds of ultraviolet absorbers are more preferably benzotriazole-based ultraviolet absorbers and three It is a UV absorber. That is, it is preferred that the functional layer contains a benzotriazole-based ultraviolet absorber and three It is a UV absorber. Thereby, the white turbidity of the functional layer can be effectively suppressed, and the haze value of the functional layer can be suppressed to be low. Further, the transmittance of light having a wavelength of 300 to 380 nm can be suppressed low and the b* value can be suppressed.

About the ultraviolet absorber contained in the functional layer, three The higher the mass ratio of the ultraviolet absorber, the lower the transmittance of light having a wavelength of 300 to 350 nm can be suppressed, and the more the mass ratio of the benzotriazole-based ultraviolet absorber, the more the haze of the functional layer can be suppressed. Value and b* value. Benzotriazole UV absorber and three The quality of the ultraviolet absorber is preferably 1:1~1:3.

(3) Additives that can be used in the functional layer

As the additive which can be used in combination in the functional layer of the present invention, a light stabilizer represented by a hindered amine compound can be preferably exemplified. also. It is also preferred to use an antioxidant represented by a hindered phenol compound. Antioxidants are generally classified into an initial antioxidant called a radical chain terminator and a secondary antioxidant that acts as a peroxide decomposer. Examples of the initial antioxidant include hindered phenol-based antioxidants, amine-based antioxidants, and lactone-based antioxidants. Further, examples of the secondary antioxidant include a phosphorus-based antioxidant and a sulfur-based antioxidant.

These antioxidants may be used alone or in combination of two or more.

The content of the additive to be used in combination with respect to 100 parts by mass of the acrylic polymer is preferably 0.03 to 1.5 parts by mass, more preferably 0.05 to 1.0 part by mass. When the content is at least the above lower limit value, the ultraviolet absorbing property at a high temperature, a low temperature, and a hot and humid environment for long-term use can be reliably maintained. When the content is at most the above upper limit value, the transmittance of 300 to 380 nm can be further prevented from increasing. Or a reduction in adhesion characteristics.

The functional layer may contain additives other than the above, such as a thickener, a decane coupling agent, and a metal corrosion inhibitor, as needed. Examples of the thickener include a rosin-based resin, a terpene-based resin, a terpene-phenol-based resin, a kasuga-ruthenium-based resin, a styrene-based resin, a xylene-based resin, a phenol-based resin, and a petroleum resin. Examples of the decane coupling agent include a mercapto alkoxydecane compound (for example, a mercapto-substituted alkoxy oligomer). As the metal corrosion preventing agent, a type which forms a complex with a metal and forms a film on the surface of the metal to prevent corrosion is preferable, and a benzotriazole-based metal corrosion inhibitor is particularly preferable.

The thickness of the functional layer is preferably set to 10 to 100 μm, more preferably 15 to 50 μm. When the thickness is 10 μm or more, sufficient adhesion can be ensured, and even if it is used for a long period of time, bulging or peeling is unlikely to occur, and ultraviolet rays can be sufficiently absorbed. In addition, when the thickness of the functional layer is 100 μm or less, there is an advantage in that when the adhesive sheet is cut into a size of a display, it is less likely that the adhesive adheres to the dicing blade or the like and the failure rate increases.

<conductive layer>

The laminate of the present invention may also have a conductive layer. The conductive layer is preferably provided on the side of the hard coat layer including a layer of a transparent base material layer and a hard coat layer which are laminated with an easy-to-adhere layer. The conductive layer may be directly laminated on the hard coat layer, or may be laminated by providing other substrate layers or the like therebetween.

The conductive layer may also be a uniform layer having substantially uniform electrical conductivity in the in-plane direction on the laminated body used in the surface type capacitive touch panel or the like. Further, it may be a conductive layer used in a projection type capacitive touch panel or the like, or may be a conductive layer which is provided with a part of an insulating portion in the surface for the purpose of position detection and whose conductive properties are regularly patterned. Floor. Further, a protective film for preventing oxidation of the conductive film may be further formed on the conductive layer.

The conductive property of the conductive layer can be expressed, for example, by the surface resistance measured by the method described in JIS-K7194. In order to form an electrode plate for a touch panel, the surface resistance is preferably 1 × 10 ⁵ Ω/sq or less, more preferably 1 ×10 ³ Ω/sq or less. Further, the surface resistance is preferably 1 Ω/sq or more, more preferably 1 × 10 ² Ω/sq or more. The surface resistance of the conductive layer is preferably in the range of 1 to 1 × 10 ⁵ Ω/sq, more preferably 1 × 10 ² to 1 × 10 ³ Ω/sq.

On the other hand, in order to perform more accurate position detection of the touch panel, for example, it is preferable to set the surface resistance measured by the method described in JIS-K6911 to 1 × 10 ⁹ Ω/sq. The above is more preferably 1 × 10 ¹¹ Ω/sq or more, and is set to 1 × 10 ¹³ Ω/sq or less, more preferably 1 × 10 ¹² Ω/sq or less, and is clearly insulated. The surface resistance of the insulating portion is preferably in the range of 1 × 10 ⁹ to 1 × 10 ¹³ Ω/sq, more preferably 1 × 10 ¹¹ to 1 × 10 ¹² Ω/sq.

In the case where it is convenient to apply a substantially uniform conductive layer, depending on the configuration of the touch panel or the like, a portion of the vicinity of the outer periphery of the conductive layer may be patterned in order to form an extraction electrode or the like.

As the material of the conductive layer, a known conductive material can be applied. An inorganic material may be used as the conductive material, and examples of the inorganic material include metals such as gold, silver, copper, aluminum, nickel, and cobalt, or indium tin oxide (ITO). Indium-zinc oxide (IZO), zinc oxide (Zinc Oxide (ZnO)), or zinc-tin oxide (Zinc Tin Oxide (ZTO)), or bismuth-tin oxide (ATO) Oxide. An organic conductive material can be used as the conductive material. Examples of the organic conductive material include a conductive carbon material such as a conductive carbon nanotube or graphene, or a conductive polymer such as polythiophene or polyaniline. Limited to these.

Among them, as the inorganic material, ITO can be optimally used in terms of high reliability and excellent transparency and conductivity. Moreover, PEDOT/PSS which is one type of organic conductive polymer polythiophene can also be preferably used in terms of characteristics excellent in flexibility and excellent in transparency and conductivity. The PEDOT/PSS means a polymer complex in which PEDOT (a polymer of 3,4-ethylenedioxythiophene) and PSS (a polymer of styrenesulfonic acid) are present.

Compared with a conductor having a relatively high transparency like ITO or PEDOT/PSS, the transparency of the metal or the conductive carbon material is poor. Therefore, when a metal or a conductive carbon material is used as the material of the conductive layer, the following is as follows. It is preferable to use a metal or a conductive carbon material to be nanowired and coated, or processed into a mesh shape, thereby ensuring transparency. Among them, since silver is the most excellent electrical conductor, it can be preferably used.

The thickness of the conductive layer must be set in consideration of the conductivity or transparency of the conductor to be applied, and the thickness is not particularly limited. For example, in the case of a metal system, it is preferably 30 to 600 Å, and the metal oxide or organic system is used. In the case, it is preferably a thickness of 80 to 5000 Å.

The conductive layer can be formed by a known method. For example, when the conductive layer is a uniform layer, a vacuum deposition method, a sputtering method, an ion plating method, a spray pyrolysis method, an electroless plating method, an electroplating method, a coating method, or a combination thereof may be mentioned. Film formation method such as law. The vacuum deposition method or the sputtering method is preferred in terms of film formation speed, formation of a large-area film, or productivity.

The regular pattern can be pre-arranged on a transparent substrate by various printing methods or the like. It may be formed by partially providing a conductive layer, or may be formed by forming a uniform layer as described above and then removing a part thereof by etching or the like.

Before the formation of the conductive layer, the surface of the laminate may be subjected to appropriate pre-treatment such as corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, sputtering etching treatment, or primer treatment to improve adhesion.

<peeling layer>

A release layer may be further formed on the surface of the functional layer of the laminate of the present invention. The functional layer of the laminate contains an adhesive, so if it is exposed, it may adhere to an unintentional article or the functional layer itself may deteriorate. Therefore, in order to physically and chemically protect the functional layer, a peeling layer may be provided in advance on the surface of the functional layer, and the peeling layer may be peeled off during use to expose the functional layer, and then bonded to other members.

Examples of the release layer include a release agent such as polyfluorene oxide which is applied to various plastic films to form a release agent layer, a polypropylene film monomer, and the like, and can be used as a release sheet for a usual adhesive sheet. .

<Formation method of laminated body>

As a method of forming the layered body of the present invention, for example, a composition for forming a functional layer containing an adhesive and an ultraviolet absorber is applied onto the release layer, and after drying to form a functional layer, the functional layer is laminated and transparent. A method of coating a base material layer; or a method of applying a composition for forming a functional layer on a transparent base material layer, drying the layer to form a functional layer, and then laminating the release layer on the functional layer. Examples of the coating method of the composition for forming a functional layer include a Mayer-Bar coater, a roll coater, a knife coater, a gravure coater, a lip coater, and a curtain coat. A coating method such as a cloth machine or a die coater.

[Reduce rainbow spot generation sheet]

The reduced rainbow spot generating sheet of the present invention is characterized in that it is a sheet containing the above functional layer, and contains an adhesive and an ultraviolet absorber. By laminating such a sheet to a transparent substrate layer comprising a transparent substrate layer laminated with an easy-to-adhere layer and a hard coating film of a hard coat layer On the side, the rainbow spots that occur in the hard coat film can be reduced. Especially in the case of high-humidity conditions or long-term use under ultraviolet irradiation conditions, the occurrence of rainbow spots can be effectively suppressed.

In the reduced rainbow spot generating sheet of the present invention, the release sheet may be laminated on both sides before the bonding function layer, and then one of the release sheets may be peeled off and bonded to the hard substrate layer and the hard coat layer. The side of the transparent substrate layer of the coating film can also be formed by directly applying it to the side of the transparent substrate layer containing the transparent substrate layer and the hard coat film of the hard coat layer. For details of the release sheet, reference can be made to the description of the release layer described above.

After the reduced rainbow-ray generating sheet of the present invention is bonded to the transparent substrate layer, the other members are bonded to the adhesive exposed surface of the reduced rainbow-generated sheet. For example, it can be widely applied to a supporting member such as glass or an optical member. There is no particular limitation on the type or size thereof.

[Examples]

The features of the present invention will be further specifically described below by way of examples and comparative examples. The materials, the amounts, the ratios, the processing contents, the processing order, and the like shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the invention should not be construed as limited by the specific examples shown below.

(Example 1)

<Production of Transparent Substrate Layer>

The PET pellets were vacuum dried, supplied to an extruder, melt extruded into a sheet form, and stretched. Further, the composition for easy adhesion layer formation (A) was applied to both surfaces by a roll coater, and then extended in the width direction, and a PET film having a thickness of 50 μm was used to obtain an easy-adhesion layer having a thickness of 100 nm on both surfaces. A PET film (50) with a double-sided easy-adhesion layer is attached. Similarly, a PET film (75) having a double-sided easy-adhesion layer having an easy-adhesion layer having a thickness of 100 nm on both sides was obtained using a PET film having a thickness of 75 μm. The composition (A) which is an easy-to-adhere layer is composed of 100 parts by mass of a polyester resin, and 5 parts by mass of a melamine-based crosslinking agent (trade name: NIKALAC MW12LF, manufactured by SANWA CHEMICAL Co., Ltd.), colloidal cerium oxide (product) Name: Snowtex OL, manufactured by Nissan Chemical Industries Co., Ltd.) 1 part by mass of coating. Further, it was diluted to 10% by mass using ethanol/isopropyl alcohol = 1:1 as a diluent solvent.

<Production of Hard Coating Film>

The hard coat layer-forming composition (B) was bar-coated on the above-mentioned PET film (50) with a double-sided easy-adhesion layer or a PET film (75) with a double-sided easy-adhesion layer. The composition (B) for forming a hard coat layer contains 64.1 parts by mass of a hexafunctional acrylate (trade name: DPHA, manufactured by Daicel-Cytec Co., Ltd.) as a polyfunctional (meth) acrylate, and diethylene glycol diacrylate (product) 27.5 parts by mass of a photopolymerization initiator (trade name: IRGACURE 184, manufactured by BASF Corporation), 4 parts by mass of a light stabilizer (TINUVIN 152, manufactured by BASF Corporation), 4 parts by mass of a coating material. MEK/cyclohexanone = 1:1 was used as a diluent solvent, and diluted to 50% by mass. Thereafter, the film was dried by heating at 80 ° C for 60 seconds, and was subjected to a nitrogen gas atmosphere using a high-pressure mercury lamp ultraviolet irradiation machine (manufactured by EYE GRAPHICS Co., Ltd.) at 160 W/cm, a lamp height of 13 cm, and a belt speed of 10 m/min. The hard coat layer was hardened to form a hard coat layer having a thickness of 2 μm, whereby a hard coat film (50) or a hard coat film (75) was obtained.

<Preparation of adhesive for functional layer>

After a nitrogen gas was sealed in a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, a drip device, and a nitrogen gas introduction tube, ethyl acetate as a solvent was added. Next, 65 parts by mass of butyl acrylate as an acrylic monomer, 35 parts by mass of methyl acrylate, 2 parts by mass of acrylic acid, and 2,2'-azoisobutyronitrile 0.1 as a polymerization initiator were added to the reaction apparatus. The mixture was polymerized under a nitrogen gas stream at a reflux temperature of the solvent for 8 hours while stirring. After completion of the reaction, toluene was added to obtain an acrylic polymer solution. To 100 parts by mass of the acrylic polymer solid content component, 2.0 parts by mass of a hindered amine compound (product name: TINUVIN 144, manufactured by BASF Corporation) as a light stabilizer was added, and a hindered phenol compound as an antioxidant was further added (trade name: IRGANOX 1520L, manufactured by BASF Corporation, 0.08 parts by mass to prepare an adhesive main agent.

Next, 1 part of toluene diisocyanate (product name: Coronate L, manufactured by Japan Polyurethane Co., Ltd.) as a crosslinking agent is mixed with 100 parts by mass of the solid component of the adhesive main agent, and has a maximum at a wavelength of 353 nm. An absorbing agent solution was obtained by absorbing a wavelength of a benzotriazole-based liquid ultraviolet absorber (product name: TINUVIN 109, manufactured by BASF Corporation) of 6.0 parts by mass.

<Production of reduced rainbow spot generation sheet (functional layer) with release film>

The adhesive was applied onto the surface of the uncoated hard coat layer of the hard coat film (50) by a knife coater so that the coating amount after drying was 25 μm/m ² , and dried at 100 ° C for 2 minutes. Forming a functional layer to obtain a laminate. Next, a PET release film (product name: RL07 (L) #38, manufactured by Oji F-Tex Co., Ltd.) having a thickness of 38 μm was attached to the surface of the functional layer.

(Example 2)

Adhesion was obtained in the same manner as in Example 1 except that the amount of addition of the benzotriazole-based liquid ultraviolet absorber (product name: TINUVIN 109, manufactured by BASF Corporation) having a maximum absorption wavelength at a wavelength of 353 nm was changed to 0.5 parts by mass. Solution solution. Then, this adhesive solution was applied onto the surface of the uncoated hard coat layer of the hard coat film (75) in the same manner as in Example 1 to obtain a laminate.

(Example 3)

Adhesion was obtained in the same manner as in Example 1 except that the amount of addition of the benzotriazole-based liquid ultraviolet absorber (product name: TINUVIN 109, manufactured by BASF Corporation) having a maximum absorption wavelength at a wavelength of 353 nm was changed to 2.0 parts by mass. Solution solution. Then, this adhesive solution was applied onto the surface of the uncoated hard coat layer of the hard coat film (75) in the same manner as in Example 1 to obtain a laminate.

(Example 4)

The adhesive solution of Example 3 was applied to the surface of the uncoated hard coat layer of the hard coat film (50) in the same manner as in Example 1 to obtain a laminate.

(Example 5)

In addition to changing the UV absorber to hydroxyphenyl three with a maximum absorption wavelength at a wavelength of 356 nm An adhesive solution was obtained in the same manner as in Example 1 except that a liquid ultraviolet absorber (product name: TINUVIN 477, manufactured by BASF Corporation) was used. Then, using the adhesive solution, a laminate was obtained in the same manner as in Example 1.

(Example 6)

In addition to the ultraviolet absorber, the hydroxyphenyl group having the maximum absorption wavelength at a wavelength of 356 nm An adhesive solution was obtained in the same manner as in Example 5 except that the amount of the liquid ultraviolet absorber (product name: TINUVIN 477, manufactured by BASF Corporation) was 0.5 parts by mass. Then, this adhesive solution was applied onto the surface of the uncoated hard coat layer of the hard coat film (75) in the same manner as in Example 1 to obtain a laminate.

(Example 7)

In addition to the ultraviolet absorber, the hydroxyphenyl group having the maximum absorption wavelength at a wavelength of 356 nm An adhesive solution was obtained in the same manner as in Example 3 except that the amount of the liquid ultraviolet absorber (product name: TINUVIN 477, manufactured by BASF Corporation) was 2 parts by mass. Then, this adhesive solution was applied onto the surface of the uncoated hard coat layer of the hard coat film (75) in the same manner as in Example 1 to obtain a laminate.

(Example 8)

The same adhesive solution as in Example 7 was applied to the surface of the uncoated hard coat layer of the hard coat film (50) in the same manner as in Example 1 to obtain a laminate.

(Example 9)

As the ultraviolet absorber contained in the functional layer, a benzotriazole-based liquid ultraviolet absorber (product name: TINUVIN 109, manufactured by BASF Corporation) and hydroxyphenyl three are used. An adhesive solution was obtained in the same manner as in Example 1 except that a total of 4 parts by mass of the liquid ultraviolet absorber (product name: TINUVIN 477, manufactured by BASF Corporation) was mixed in a mass ratio of 1:1. . Then, this adhesive solution was applied onto the surface of the uncoated hard coat layer of the hard coat film (75) in the same manner as in Example 1 to obtain a laminate.

(Embodiment 10)

As a UV absorber contained in the functional layer, a benzotriazole-based liquid ultraviolet absorber (product name: TINUVIN 109, manufactured by BASF Corporation) and hydroxyphenyl three An adhesive solution was obtained in the same manner as in Example 9 except that the liquid ultraviolet ray absorbing agent (product name: TINUVIN 477, manufactured by BASF Corporation) was mixed in a total mass ratio of 1:1. . Then, this adhesive solution was applied onto the surface of the uncoated hard coat layer of the hard coat film (75) in the same manner as in Example 1 to obtain a laminate.

(Example 11)

The adhesive solution of Example 10 was applied to the surface of the uncoated hard coat layer of the hard coat film (50) in the same manner as in Example 1 to obtain a laminate.

(Embodiment 12)

As the ultraviolet absorber contained in the functional layer, a benzotriazole-based liquid ultraviolet absorber (product name: TINUVIN 109, manufactured by BASF Corporation) and hydroxyphenyl three are used. An adhesive solution was obtained in the same manner as in Example 9 except that the liquid ultraviolet ray absorbent (product name: TINUVIN 477, manufactured by BASF Corporation) was mixed in a total mass ratio of 1:3. . Then, this adhesive solution was applied onto the surface of the uncoated hard coat layer of the hard coat film (75) in the same manner as in Example 1 to obtain a laminate.

(Example 13)

The same adhesive solution as in Example 12 was applied to the surface of the uncoated hard coat layer of the hard coat film (50) in the same manner as in Example 1 to obtain a laminate.

(Comparative Example 1)

An adhesive solution was obtained in the same manner as in Example 1 except that the ultraviolet absorber was not added. Then, using the adhesive solution, a laminate was obtained in the same manner as in Example 1.

(Comparative Example 2)

The same method as in Comparative Example 1 except that the hard coat film (75) was used as the transparent substrate. The layer is obtained.

<Rain spot occurrence evaluation>

The rainbow spot occurrence evaluation was carried out by a weather resistance test. In the weather resistance test, the laminate in which the release sheet was peeled off was subjected to QUV-promoted exposure using a weather resistance tester manufactured by Q Panel. Regarding the test conditions, the irradiation amount of UVA light at 340 nm was 0.68 W/m ² × 8 hours / 60 ° C, and water condensation was carried out for 4 hours / 50 ° C for 1 cycle, and 15 cycles were continuously performed. For the samples after the weather resistance test, the occurrence of rainbow spots was visually confirmed. The case where the rainbow spot was not confirmed was evaluated as "○", and the case where the rainbow spot was confirmed was evaluated as "x". The results are shown in Table 1.

In the comparative example in which the rainbow spot occurred, it was found that a bulge occurred between the hard coat layer and the easy-adhesion layer. The rainbow spot can be considered to be caused by bulging between the hard coat layer and the easy-adhesion layer, and discoloration of the hard coat film. In the present invention, it can be considered that the function is laminated on the hard coat film. The layer can suppress the occurrence of ridges between the hard coat layer and the easy-adhesion layer, thereby suppressing the occurrence of rainbow spots.

According to Table 1, we know that three The more the number of parts, the lower the transmittance at 340 nm and 380 nm becomes. It is also known that the more the fraction of the benzotriazole system, the lower the b* value becomes.

Adding benzotriene In the case of a UV absorber and a benzotriazole-based ultraviolet absorber, no increase in haze was observed. In the present invention, it is considered that by adding two kinds of ultraviolet absorbers, it is possible to suppress an increase in haze or b* value and achieve a low ultraviolet transmittance.

With respect to the reduced rainbow spot generating sheet which satisfies the conditions of the present invention, even when the laminated body having the hard coat layer and the transparent base material layer laminated with the easy-to-adhere layer is placed under too severe conditions for a long period of time, Can reduce the occurrence of rainbow spots.

1‧‧ ‧ laminated body

10‧‧‧hard coating

11‧‧‧Easy layer

12‧‧‧Transparent substrate layer

13‧‧‧ functional layer

Claims (15)

A laminate having a structure in which a hard coat layer, an easy-adhesion layer, a transparent substrate layer, and a functional layer containing an ultraviolet absorber and an adhesive are sequentially laminated. The laminate according to claim 1, wherein the hard coat layer is a layer containing an acrylic resin and has a thickness of 0.5 to 20 μm. The laminate according to claim 1, wherein the transparent base material layer is a layer containing a polyester resin and has a thickness of 10 to 300 μm. The laminate according to claim 1, wherein the easy-adhesion layer is a layer containing an acrylic resin or a polyester resin, and has a thickness of 0.1 nm to 1 μm. The laminate according to any one of claims 1 to 4, wherein the easy-to-adhere layer is formed of a single layer. The laminate according to any one of claims 1 to 4, wherein the functional layer has a UV transmittance of less than 5% at a wavelength of 340 nm. The laminate according to any one of claims 1 to 4, wherein the ultraviolet absorber contains at least one compound which is oily or liquid at 23 ° C and is 100 parts by mass based on the solid content of the functional layer. It is contained in an amount of 0.5 to 8 parts by mass. The laminate according to any one of claims 1 to 4, wherein the functional layer contains at least two ultraviolet absorbers. The laminate according to any one of claims 1 to 4, wherein the functional layer contains a benzotriazole-based ultraviolet absorber and three It is a UV absorber. The laminate according to claim 9, wherein the functional layer contains the benzotriazole-based ultraviolet absorber and the above three in a mass ratio of 1:1 to 1:3. It is a UV absorber. The laminate according to any one of claims 1 to 4, further comprising a release layer on the functional layer. The laminate according to any one of claims 1 to 4, further comprising a member on the functional layer. The laminate of claim 12, wherein the member is glass. The invention relates to a sheet for reducing rainbow incidence, which is characterized in that: a pattern of a hard-coating film which has a hard coating layer, an easy-to-layer layer and a hard coating layer of a transparent substrate layer, and contains an ultraviolet absorber and an adhesive. . The invention relates to a method for reducing rainbow spot generation, which is characterized in that: a method for reducing rainbow spots in a hard coating film with a hard coating layer, an easy adhesion layer and a transparent substrate layer, and a transparent substrate layer side of the above layer On the surface, a functional layer containing an ultraviolet absorber and an adhesive is sequentially laminated.