TW201624127A - Photo-curable resin composition and method for producing laminate using the same - Google Patents

Abstract

The present invention discloses a photo-curable resin composition containing: a multifunctional (meth)acrylate which is bi-or more functional (meth)acrylate, a reactive urethane polymer, a photopolymerizable initiator and an ultraviolet absorbent.

Description

Photocurable resin composition, and method for producing a laminate using the same

The present invention relates to a photocurable resin composition and a method for producing a laminate (cured film) using the composition.

As a photocurable resin composition for forming a hard coat layer on a transparent base film, for example, a photocurable resin composition containing an ultraviolet absorber, a urethane acrylate, and a photopolymerization initiator is known ( Patent Document 1).

Prior technical literature

Patent literature

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2009-6513 (paragraph 0062)

On the other hand, when the hard coat layer is formed from the photocurable resin composition described in Patent Document 1, the obtained hard coat film containing the transparent base film and the hard coat layer cannot sufficiently satisfy the flexibility.

The present invention contains the inventions described in the following [1] to [13].

[1] A photocurable resin composition comprising: a difunctional or higher polyfunctional (meth) acrylate, a reactive urethane polymer, a photopolymerization initiator, and an ultraviolet absorber; [2] [1] The photocurable resin composition according to [1], wherein the reactive urethane polymer contains: a urethane polymer having a main chain of a polyurethane chain and a bond in the main chain a (meth) acrylate group at the end (a urethane polymer having a (meth) acrylate at the end); or a urethane-modified (meth) acrylate resin having a (meth) acrylate a main chain of the resin, a side chain bonded to the main chain and containing a polyurethane chain, and a (meth) acrylate group bonded at the end of the side chain (having a methyl group at the terminal in the side chain) a (meth)acrylic resin acrylate acrylate oligomer; or a combination thereof; [3] The photocurable resin composition according to [1] or [2], wherein 100 parts by mass of the difunctional or higher polyfunctional (meth) acrylate and the reactive urethane polymer, and the content of the reactive urethane polymer is 10~ 50 parts by mass; [4] a laminate comprising: a base film; and a cured film laminated on at least one side of the base film as in any one of [1] to [3] [5] The laminated body according to [4], wherein the laminated body having a width of 1 cm and a length of 8 cm is wound around a 6 mm-diameter roller with the cured film as the inner side. When the crack is generated in the cured film, it is 4 or less; [6] The laminated body according to [4] or [5], wherein the laminated body having a width of 1 cm and a length of 8 cm is wound around a roller having a diameter of 6 mm by using the cured film as the outer side, and the turtle produced in the cured film [7] The laminated body according to any one of [4], wherein the laminated body having a width of 1 cm and a length of 8 cm is wound around a diameter of 2 mm by using the cured film as the inner side. The laminated body according to any one of [4] to [7], wherein the hardened film has a width of 1 cm as the outer side, When the laminated body having a length of 8 cm is wound around a roller having a diameter of 2 mm, the number of cracks generated in the cured film is 4 or less; [9] The laminated body according to any one of [4] to [8], The laminate system has a pencil hardness of 4B or more; [10] The laminate according to any one of [4] to [9] wherein the laminate system has a pencil hardness of HB or more; [11] such as [9] The laminate according to the above aspect, wherein the laminate system has a pencil hardness of more than H; [12] The laminate (multilayer laminate) according to any one of [4] to [11], wherein The system has a different functional layer than the cured film; (13) A method of producing a laminate comprising the composition of the photocurable resin composition according to any one of [1] to [3], which is formed on one surface side of the substrate film. The step of layering (the step of obtaining a composition layer by coating the photocurable resin composition according to any one of [1] to [4] on the substrate film), and (2) by the aforementioned composition a step of exposing the layer to harden the layer of the composition to form a cured film; [14] The method according to [13], wherein the substrate film is a polyimide film.

According to the photocurable resin composition of the aspect of the invention, even if the cured film formed of the photocurable resin composition is formed on the transparent base film, a laminate having excellent flexibility can be obtained (for example, hard Coating film).

10‧‧‧Substrate film

10a‧‧‧Main surface of the substrate film

20‧‧‧ hardened film

30‧‧‧Layered body

Fig. 1 is a cross-sectional view showing an embodiment of a laminated body.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. First, a photocurable resin composition relating to an aspect will be described.

Photocurable resin composition

The photocurable resin composition contains a difunctional or higher polyfunctional (meth) acrylate, a reactive urethane polymer, a photopolymerization initiator, and an ultraviolet absorber. In the present specification, "(meth) acrylate" means a general term for both acrylate and methacrylate.

A polyfunctional (meth)acrylate is a compound which has two or more (meth)acrylate groups. The polyfunctional (meth) acrylate may further contain: a difunctional (meth) acrylate having two (meth) acrylate groups, and a trifunctional (methyl) having three (meth) acrylate groups. Acrylate.

Examples of the difunctional or higher polyfunctional (meth) acrylate include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and new Pentylene glycol (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, dipropylene glycol di (methyl) Acrylate, 3-methylpentanediol di(meth)acrylate, diethylene glycol double β-(meth)acryloxy propionate, trimethylolethane tri(meth)acrylate , trimethylolpropane tri (meth) acrylate, neopentyl alcohol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris (2-hydroxyethyl) isocyanate di ( Methyl) acrylate, neopentyl alcohol tetra(meth) acrylate, 2,3-bis(methyl) propylene methoxy ethoxymethyl [2.2.1] heptane, poly 1,2-butyl Diene di(meth)acrylate, 1,2-bis(methyl)propenyloxymethylhexane, nonaethylene glycol di(meth)acrylate, tetradecanediol di(methyl) Acrylate, 10-decanediol (meth) acrylate, 3,8-bis(meth) propylene methoxymethyl three [5.2.10] decane, hydrogenated bisphenol A di(meth) acrylate, 2,2-bis(4-(methyl) propylene decyloxydiethoxyphenyl) propane, 1,4-double ((Meth)acryloxymethyl)cyclohexane, hydroxytrimethylacetate neopentyl glycol di(meth)acrylate, bisphenol A diglycidyl di(meth)acrylate And epoxy modified bisphenol A di(meth) acrylate. These may be used alone or in combination of two or more.

The reactive urethane polymer is a polymer having a polyurethane chain and a reactive functional group which is reacted by ultraviolet rays. The reactive functional group is, for example, a (meth) acrylonitrile group. The reactive urethane polymer may be a UV-curing urethane acrylate polymer or may be on the side The chain has a (meth)acrylic resin of a UV-curable urethane acrylate oligomer. More specifically, the reactive urethane polymer may further comprise: a urethane polymer, a urethane-modified (meth) acrylate resin, or a combination thereof, wherein the urethane polymer A main chain having a polyurethane chain and a (meth) acrylate group bonded to a terminal of the main chain; the urethane-modified (meth)acrylic resin having a (meth)acrylic resin The main chain is bonded to the main chain and contains a side chain of a polyurethane chain and a (meth) acrylate group bonded to the end of the side chain. The polyurethane chain is derived from the divalent group of the urethane polymer or the urethane oligomer.

The main chain of the urethane-modified (meth)acrylic resin is an unmodified (meth)acrylic resin, which is usually mainly composed of (meth) acrylate (methyl (meth) acrylate, etc.). The polymer formed. The urethane-modified (meth)acrylic resin has, for example, a structural unit represented by the following formula (1). The structural unit may contain only one type of the reactive urethane polymer, or may contain two or more types, and the total structural unit of the reactive urethane polymer may be 50% by weight or more. A structural unit represented by the formula (1).

In the formula (1), n represents an integer of 1 to 10. R ¹ and R ² each independently represent an alkylene group having 2 to 6 carbon atoms, and R ³ represents a polyurethane chain (divalent derived from a urethane polymer or a urethane oligomer) And R ⁴ and R ⁵ each independently represent a methyl group or a hydrogen atom.

Examples of the alkylene group having 2 to 6 carbon atoms of R ¹ or R ² include a vinyl group, a propenyl group, a butenyl group, a pentanediyl group, and a hexanediyl group.

The polyurethane chain of R ³ may also be a divalent group derived from a urethane polymer having a molecular weight of 3,000 to 4,000 or an urethane oligomer having a molecular weight of 350 to 600. The divalent group derived from a urethane polymer or a urethane oligomer is a group obtained by removing two hydrogen atoms from a urethane polymer or a urethane oligomer.

As a commercial product containing a reactive urethane polymer (a urethane-modified (meth)acrylic resin of the structural unit of the formula (1)), 8BR-500 manufactured by Daisei FINE CHEMICAL Co., Ltd. , 600, 650, 930, etc.

The content of the reactive urethane polymer may be 5 to 60 parts by mass, or 10 to 50 parts by mass, based on 100 parts by mass of the total of the polyfunctional (meth) acrylate and the reactive urethane polymer. When the content of the reactive urethane polymer is large, the pencil hardness on the surface of the laminate tends to decrease. When the content of the reactive urethane polymer is small, the effect of improving the flexibility tends to be small. The total content of the polyfunctional (meth) acrylate and the reactive urethane polymer may be 4.5% by mass or more, 9% by mass or more, or 36% by mass or more based on the total amount of the photocurable resin composition. It may be 55 mass% or less or 45 mass% or less.

Photopolymerization initiator can be present in the presence of UV absorbers A polymerization initiator capable of exhibiting photopolymerization initiation energy by light irradiation. Examples of such a photoinitiator include acetophenone, acetophenone benzyl ketal, anthracene, and 1-(4-isopropylphenyl-2-hydroxy-2-methylpropane-1- Ketone, oxazole, xanthone, 4-chlorodiphenyl ketone, 4,4'-diaminodiphenyl ketone, 1,1-dimethoxyoxybenzoin, 3,3' - dimethyl-4-methoxydiphenyl ketone, 9-thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 1-(4-12 Phenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinepropan-1-one, triphenyl Amine, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzylidene)phenylphosphine oxide, 1-hydroxycyclohexylbenzene Ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, anthrone, anthracene, benzaldehyde, benzoin ethyl ether, benzoisopropyl ether, diphenyl ketone, michlerone , 3-methylacetophenone, 3,3',4,4'-tetra-t-butylperoxycarbonyldiphenyl ketone (BTTB), 2-(dimethylamino)-1-[4- (morpholinyl)phenyl]-2-(benzyl)-1-butanone, 4-benzylidene-4'-methyldiphenyl sulfide, and benzyl.

The photopolymerization initiator may be used alone or in combination of two or more. For example, when a thick cured film is formed in an amount of 10 μm or more, when two or more kinds of photopolymerization initiators are used, the curability tends to be improved. When the hardenability is improved, the photocurable resin composition can be sufficiently cured more easily.

The content of the photopolymerization initiator may be 1 to 15 parts by mass, or 3 to 10 parts by mass, based on 100 parts by mass of the total of the polyfunctional (meth) acrylate and the reactive urethane polymer. When the content of the photopolymerization initiator is large, a photopolymerization initiator which is not used at the beginning of photopolymerization remains. It can cause disadvantages such as a decrease in visible light transmittance of the cured film. On the other hand, when the content of the photopolymerization initiator is small, the photopolymerization initiation energy is not sufficiently exhibited, and the ultraviolet curable resin tends to be hardly sufficiently cured.

A known ultraviolet ray absorbing agent can be used. However, in order to obtain ultraviolet absorbing energy (ultraviolet ionic energy) which is high in ultraviolet absorbing property and used in an electronic image display device, the photocurable resin composition may contain a benzotriazole system. Or a hydroxyphenyl triazine-based ultraviolet absorber. In order to increase the absorption width of ultraviolet rays, it is also possible to use two or more kinds of ultraviolet absorbers having different maximum absorption wavelengths.

Examples of the benzotriazole-based ultraviolet absorber include 2-[2'-hydroxy-5'-(methacryloxymethyl)phenyl]-2H-benzotriazole and 2-[2'. -hydroxy-5'-(methacryloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloxypropyl)phenyl -2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloxyl hexyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-3' -T-butyl-5'-(methacryloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-tert-butyl-3'-( Methyl propylene oxiranyl ethyl) phenyl]-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloxyethyl)phenyl]-5-chloro-2H -benzotriazole, 2-[2'-hydroxy-5'-(methacryloxyethyl)phenyl]-5-methoxy-2H-benzotriazole, 2-[2'- Hydroxy-5'-(methacryloxyethyl)phenyl]-5-cyano-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloxy) Phenyl]-5-tert-butyl-2H-benzotriazole, 2-[2'-hydroxy-5'-(methacryloxyethyl)phenyl]-5-nitro- 2H-benzotriazole, 2-(2-hydroxy-5-t-butylphenyl)-2H- Benzotriazole, phenylpropionic acid-3-(2H- Benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-, C7~9-branched linear alkyl ester, 2-(2H-benzotriazole- 2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, and 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1- Phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol and the like.

Examples of the hydroxyphenyltriazine-based ultraviolet absorber include 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]4,6-double. (2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl -4,6-bis(2,4 dimethylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy 2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butoxy Phenyl)-6-(2,4-bis-butoxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy] Phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine, 2,2',4,4'-tetrahydroxydiphenyl ketone, 2,2'-di Hydroxy-4,4'-dimethoxydiphenyl ketone, 2,2'-dihydroxy-4-methoxydiphenyl ketone, 2,4-dihydroxydiphenyl ketone, 2-hydroxy-4 - ethoxylated ethoxylated diphenyl ketone, 2-hydroxy-4-methoxydiphenyl ketone, 2,2'-dihydroxy-4-methoxydiphenyl ketone, 2,2'- Dihydroxy-4,4'-dimethoxydiphenyl ketone, 2-hydroxy-4-n-octyloxydiphenyl ketone, and 2,2'-dihydroxy-4,4'-dimethoxy -5,5'-disulfodiphenyl ketone. 2 sodium salt and so on.

The content of the ultraviolet absorber depends on the obtained ultraviolet transmittance and the absorbance of the ultraviolet absorber, but may be 100 parts by mass based on the total of the polyfunctional (meth)acrylate and the reactive urethane polymer. 1 to 10 parts by mass, or 3 to 8 parts by mass. When the content of the ultraviolet absorber is large, the curability of the photocurable resin composition is lowered by ultraviolet rays. There is a tendency that the visible light transmittance of the obtained cured film is lowered at the same time. On the other hand, when the content of the ultraviolet absorber is small, the cured film may not exhibit sufficient ultraviolet absorbing properties.

The photocurable resin composition may further contain an antistatic agent. Such antistatic agents may also be metal oxides and/or metal salts. Examples of the metal oxide include ITO (indium-tin composite oxide), ATO (yttrium-tin composite oxide), tin oxide, antimony pentoxide, zinc oxide, zirconium oxide, titanium oxide, and aluminum oxide. As a metal salt, zinc phthalate etc. are mentioned. The content of the antistatic agent is, for example, from 1 to 100 parts by mass based on 100 parts by mass of the total of the polyfunctional (meth) acrylate and the reactive urethane polymer, depending on the antistatic property. When the content of the antistatic agent is large, the ultraviolet curability of the photocurable resin composition is hindered, and the visible light transmittance of the obtained cured film tends to be lowered. Moreover, when the content of the antistatic agent is large, the obtained cured film tends to have reduced scratch resistance or a decrease in film formability. When the content of the antistatic agent is small, it tends to be difficult to obtain a sufficient antistatic effect.

The particle size of the antistatic agent may be 0.001 to 0.1 μm. An antistatic agent having a very small particle size is difficult to industrially produce. The antistatic agent having a too large particle size tends to lower the transparency of the obtained cured film.

The photocurable resin composition may contain an additive such as a stabilizer, an antioxidant, a colorant, and a leveling agent as needed. By containing a leveling agent, the smoothness and scratch resistance of the cured film can be improved.

The photocurable resin composition may further contain a solvent in order to be applied to the base film as described later. As such a solvent, for example, Examples of methanol, ethanol, 1-propanol, 2-propanol (isopropanol), 1-butanol, 2-butanol (second butanol), 2-methyl-1-propanol (isobutanol) An alcohol solvent such as 2-methyl-2-propanol (tertiary butanol); 2-ethoxyethanol, 2-butoxyethanol, 3-methoxy-1-propanol, 1- An alkoxy alcohol solvent such as methoxy-2-propanol or 1-ethoxy-2-propanol; a ketone alcohol solvent such as diacetone alcohol; acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Ketone solvent; aromatic hydrocarbon solvent such as toluene or xylene; ester solvent such as ethyl acetate or butyl acetate.

The content of the solvent is, for example, 20 to 10,000 parts by mass based on 100 parts by mass of the total of the polyfunctional (meth) acrylate and the reactive urethane polymer.

The photocurable resin composition is capable of using a polyfunctional (meth) acrylate, a reactive urethane polymer, a photopolymerization initiator, a UV absorber, a solvent, an antistatic agent, and other additives as necessary. Mixed to get. The mixing order and the like are not particularly limited.

<Laminated body>

Fig. 1 is a cross-sectional view showing an embodiment of a laminated body. The laminate 30 shown in Fig. 1 has a base film 10 and a cured film 20 laminated on a main surface 10a of the base film 10. The cured film 20 is formed of the photocurable resin composition of the above embodiment. That is, the cured film is a cured product of the photocurable resin composition. The laminate system of one embodiment has excellent flexibility, surface hardness, and light resistance.

The flexibility of the laminate can be produced in the bending test according to JIS K 5600-5-1:1999, based on the fragments in the laminate. Judging by the amount of raw cracks. For example, the following bending test can be performed. First, the laminated body is cut into a size of 1 cm in length and 8 cm in width, and a fragment of an elongated shape of the laminated body (hereinafter referred to as a measurement sample) is prepared. Next, a roller having a desired diameter was placed in the center of the measurement sample, and the measurement sample was bent about 10 times along the roller. Subsequently, it was confirmed whether or not cracks occurred in the cured film of the measurement sample.

In the bending test described above, when the cured sample of the measurement sample is wound inside the roll, the compressive stress acts on the cured film constituting the laminated body, and the tensile stress acts on the base film. . On the other hand, when the measurement sample is wound around the roll as the outer side of the cured film, the compressive stress acts on the base film constituting the laminated body, and the tensile stress acts on the cured film. The bending test was performed on each of the two methods, and the crack generated in the cured film was confirmed to evaluate the flexibility of the laminated body.

When the diameter of the roller used for measurement was small, that is, the winding diameter became small, a larger stress was applied to the measurement sample in the test. Therefore, when the diameter of the roll is small, if the occurrence of cracks in the measurement sample is suppressed, the measurement sample can have excellent bendability.

In the laminate of the embodiment, when the cured film is subjected to a bending test using a roll having a diameter of 6 mm (winding diameter: 3 mm) as the inner side or the outer side, the crack may be one or more and four or less in any case. It can also be such that no cracks are produced. In the bending test using a roller having a diameter of 6 mm, cracks are not generated when the cured film is the inner side, and one or more and four or less cracks are generated when the cured film is the outer side. In this way, it is possible to suppress the occurrence of cracks, and the cured film absorbs stress and exhibits excellent bending. Sexual orientation.

In a laminated body of a solid form, when a cured film is used as a inner side or an outer side, a bending test using a roll having a diameter of 2 mm (winding diameter: 1 mm) is used. In either case, the crack may be one or more and four. Hereinafter, it is also possible that no cracks are generated. In the laminate of one embodiment, even if the winding diameter is small and a large stress acts on the measurement sample, it is possible to suppress the occurrence of cracks and to have excellent bendability.

In the bending test of a roll having a diameter of 2 mm, when the cured film is wound as the inner side, the crack is not generated, and the crack generated when the cured film is wound as the outer side can be cracked. It is one or more and four or less. In such a manner, it is possible to suppress the occurrence of cracks in the laminate, and the cured film tends to absorb stress and exhibit excellent bendability.

According to JIS K 5600-5-4:1999, the weight of the cured film of the laminate can be measured by applying a load of 1 kg. The laminated body of one embodiment may have a pencil hardness of 4 B or more or HB or more. The pencil hardness may be H or more, or 2H or more. When the pencil hardness is HB or more, the laminated system tends to exhibit sufficient hardness as a hard coat film. The pencil hardness measured by the above method is the pencil hardness of the laminate. When another layer is further provided on the cured film, it is a pencil hardness of a laminate including the other layer.

In the bending test using a laminate of a roller having a diameter of 6 mm, the number of cracks in the laminated body is one or more and four or less, and the pencil hardness of HB or more may be obtained. In the bending test using a laminate of a roller having a diameter of 6 mm, the number of cracks in the laminate is one or more and four or less, and the pencil hardness can be 2H or more. In the use of a laminated body of a 6 mm diameter roller In the bending test, the laminated system does not cause cracks, and the pencil hardness can be 2H or more.

In the laminate of the cured film formed of the photocurable resin composition of the embodiment, the discoloration (yellowing) of the base film due to light can be suppressed, so that the light resistance is exhibited. The light resistance can be judged by the amount of change (ΔYI) of the YI value of the laminate before and after the irradiation of the light. The smaller the value of the laminated system ΔYI, the more excellent the light resistance. Here, the YI value can be calculated by the tristimulus values X, Y, and X calculated according to the calculation method defined in JIS Z 8701:1982 and the following equation.

YI=100(1.28X-1.06Z)/Y

The YI value can be measured using a commercially available spectrophotometer. For example, the YI value can be measured using the product "U-4100" manufactured by Hitachi, Ltd., or the like.

For example, when the base film is a resin film that does not contain an ultraviolet absorber or a photosensitive resin film, the light resistance of the laminate can be remarkably improved.

The cured film constituting the laminate is formed on at least one side of the base film. The thickness of the cured film may be, for example, 3 μm or more and 20 μm or less. The thickness of the cured film may be 5 μm or more and 10 μm or less. When the thickness of the cured film is within the above range, the laminate including the base film and the cured film tends to have particularly excellent bendability, hardness, and light resistance. When the cured film is too thick, although the pencil hardness is improved, in the bending test, when the cured film is set to the outside, cracking tends to occur.

The laminated body of an embodiment because of excellent bending The properties and hardness, for example, as a hard coat film, can constitute a display device simultaneously with a polarizing plate or the like. The laminate system may have other layers in addition to the base film and the cured film. For example, another functional layer may be provided on the cured film of the laminate. The functional layer may, for example, be a hard coat layer or a surface treatment layer such as an antireflection layer or an antiglare layer. The functional layer may also be laminated to the laminate through an adhesive or an adhesive. As the adhesive and the adhesive, it is sufficient to appropriately select a known one.

Since the laminated body of one embodiment has excellent flexibility and hardness, even if a functional layer is further provided, it is possible to exhibit high flexibility while exhibiting sufficient flexibility.

<Method of Manufacturing Laminates>

Next, a method of producing a laminate having a cured film formed of a photocurable resin composition according to an embodiment will be described.

The method for producing a laminate having a cured film includes, for example, the following steps (1) and (2).

(1) a step of forming a composition layer containing a photocurable resin composition on one surface side of a base film (step of applying a photocurable resin composition to a base film to obtain a composition layer)

(2) a step of hardening the composition layer by exposing the composition layer to form a cured film (step of exposing the composition layer to harden the composition layer)

<Step (1)>

The base film may also have transparency. The substrate film is a polyester such as polyethylene terephthalate (PET), polycarbonate (PC), polyarylate (PAR), polyether oxime (PES), or polyimine (PI). Film. The base film may also be a polyimide film (PI) film insofar as the effect of the cured film is particularly remarkable. The substrate film may also contain an inorganic material. The ratio of the inorganic material is usually less than 20% by mass based on the total mass of the resin and the inorganic material constituting the base film.

The thickness of the base film may be 30 to 300 μm or 50 to 200 μm. When the base film is thin, the strength of the laminate of the cured film and the base film tends to be lowered. When the base film is thick, the transparency of the base film may be lowered or the bendability may be lowered. The substrate film may also contain various additives. Examples of such an additive include a stabilizer, a plasticizer, a lubricant, and a flame retardant.

The substrate film may also have an adhesive layer disposed on the surface thereof. Next, the layer is used to adhere the cured film to the substrate film, and can be formed in accordance with a usual method. The adhesive for forming the adhesive layer can be appropriately selected depending on the material of the base film and the cured film. For example, an acrylic adhesive (adhesive), a polyoxynene adhesive (adhesive), or a polyester can be used. Followers and so on. When the thickness of the layer is small, it is difficult to obtain a sufficient adhesion. When the layer is too thick, the layered body of the cured film and the base film becomes too hard and the flexibility of the film tends to be lowered. Therefore, the thickness of the adhesive may be in the range of 0.1 to 1 μm.

Examples of the method of applying the photocurable resin composition to the base film include a roll coating method, a spin coating method, a wire bar method, and a dipping method. Stain coating method and die coating method. In terms of productivity and production cost, a method capable of continuous coating such as a roll coating method is particularly advantageous.

When the composition layer (the photocurable resin composition after coating) contains a solvent, a step (1') of removing the solvent from the composition layer may be provided. The removal of the solvent can be carried out by evaporating the solvent from the composition layer by, for example, a heating means using a heating means such as a hot plate, a decompression means using a decompressing means, or a combination thereof. The conditions of the heating means and the decompression means can be selected in accordance with the type of the solvent contained in the composition layer or the like. For example, when the plate is heated, the surface temperature of the heating plate can be set to a range of about 50 to 200 °C. The pressure reducing means may be a suitable pressure reducing machine, and the base material film having the composition layer may be enclosed in a pressure reducing machine. The pressure of the environment (the internal pressure of the pressure reducer) formed by the pressure reducing means can be, for example, about 1 to 1.0 × 10 ⁵ Pa. By removing the solvent from the composition layer, a composition layer substantially free of a solvent can be formed on the base film.

<Step (2)>

The exposure system is usually carried out by irradiating ultraviolet rays. At this time, the ultraviolet light contains light in the visible light region. The photopolymerization initiator exhibits photopolymerization initiation energy by light irradiation to harden the composition layer obtained in the step (1). Ultraviolet light can also have a wavelength of 200 to 450 nm. The photopolymerization initiator may also have an absorption region at a wavelength of 220 to 450 nm. Generally, the wavelength of ultraviolet rays is shorter than 380 nm, and the wavelength of visible light is 380 to 780 nm.

When the wavelength of ultraviolet light is less than 200 nm, the ultraviolet light is easily absorbed by the ultraviolet absorber because the photopolymerization initiator has no photopolymerization initiation energy. Since the method is sufficiently exhibited, there is a tendency that the hardenability of the constituent layer is lowered. When the wavelength of ultraviolet rays exceeds 450 nm, the function as ultraviolet rays tends to be lowered. When the wavelength of the light in the absorption region of the photopolymerization initiator is less than 220 nm, the ultraviolet light is easily absorbed by the ultraviolet absorber, and the photopolymerization initiation energy tends to be lowered. The photopolymerization initiator having a wavelength of light exceeding 450 nm in the absorption region is less in kind, and further, such a photopolymerization initiator may have insufficient photopolymerization initiation energy in the presence of ultraviolet rays.

[Examples]

Hereinafter, the above embodiments will be more specifically described by way of examples and comparative examples, but the invention is not limited by the scope of the examples.

In each of the following examples and comparative examples, each physical property was measured as follows.

<pencil hardness>

According to JIS K 5600-5-4:1999, the cured film of the laminated body was placed on the sample stage so that the cured film of the laminate was placed on the upper side, and the pencil hardness of the laminated body was measured. The load is set to 1 kg.

<bending>

The bending test was carried out in accordance with JIS K 5600-5-1:1999. The laminate of the cured film and the base film was cut into 1 cm × 8 cm to obtain a measurement sample. The measurement samples were each wound into a roll having a diameter of 6 mm or 2 mm in such a direction that the cured film became the inner side or the outer side. The flexibility is determined as follows depending on the number of cracks in the cured film.

(determination of bending property)

AA: no cracking

A: The crack is 1~4

B: There are more than 5 cracks.

C: Determination of sample material damage

[Example 1]

47.5 parts by weight of a 4-functional acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMMT, neopentyltetraol tetraacrylate), a trifunctional acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMPT, Tris-hydroxyl) 47.5 parts by mass of a reactive urethane polymer (manufactured by Daisei FINE CHEMICAL Co., Ltd., 8BR-600 40 wt%), 12.5 parts by mass, triazine-based ultraviolet absorber (manufactured by BASF Corporation, TINUVIN) (registered trademark) 479) 8 parts by mass, photopolymerization initiator (CIBA. SPECIALTY. CHEMICALS, IRGACURE (registered trademark) 184) 8 parts by mass, leveling agent (BYK-Chemie Japan) BYK-350) 0.6 parts by mass and 107 parts by mass of methyl ethyl ketone were mixed while stirring to obtain a photocurable resin composition.

The photocurable resin composition was applied to a transparent polyimide film as a transparent base film using a bar coater so that the film thickness after drying was 5 μm (Mitsubishi Gas Chemical Co., Ltd.) The amine film was 100 μm, which is described as "PI" in the table. Subsequently, the coating film (composition layer) was dried in an oven at 60 ° C for 5 minutes, and hardened by irradiation with ultraviolet rays at an energy of 500 mJ/cm ² to obtain a laminate of the cured film and the base film. The pencil hardness and flexibility of the obtained laminate were measured by the above method. The results are shown in Table 1.

The initial YI value of the laminate is 1.8, using UVCON from Atlas The device (light UV-B) had a YI value of 2.3 after 24 hours of ultraviolet irradiation of the laminate. Since the amount of change in the YI value (ΔYI) before and after the ultraviolet irradiation is 0.5, the laminated system has excellent light resistance. The YI value was measured using a spectrophotometer (product name "U-4100" manufactured by Hitachi, Ltd.).

[Examples 2 to 8 and Comparative Example 1]

The amount of the reactive urethane polymer, the triazine-based ultraviolet absorber, and the photopolymerization initiator was changed in the same manner as in Example 1 except that the amounts described in Table 1 or Table 2 were changed. A laminate of the cured film and the base film is obtained. The results of measuring the pencil hardness and flexibility of the obtained laminate were shown in Tables 1 and 2.

In the laminates obtained in Examples 2 to 8, in the same manner as in Example 1, the amount of change in the YI value was small and the light resistance was excellent.

[Embodiment 9]

In the same manner as in Example 6, except that a polyethylene terephthalate film (manufactured by TORAY Co., Ltd., biaxially stretched polyester film Lumirror, thickness: 75 μm, referred to as "PET" in the table) was used as the transparent base film. The laminate was obtained by carrying out. The results of measuring the pencil hardness and flexibility of the obtained laminate were shown in Table 2.

In the same manner as in the first embodiment, the laminated system has a small amount of change in the YI value and excellent light resistance.

[Comparative Example 2]

The pencil hardness and the flexibility of the transparent polyimide film (100 μm of a polyimine film made by Mitsubishi Gas Chemical Co., Ltd.) were measured without forming a cured film. The results are shown in Table 1.

The YI value before and after the ultraviolet irradiation of the transparent polyimide film was measured in the same manner as in Example 1. The YI value before ultraviolet irradiation was 1.8, the YI value after irradiation was 11.2, and the amount of change (ΔYI) was 9.4. It was confirmed that the transparent polyimide film after ultraviolet irradiation was yellowed.

[Embodiment 10]

Photocuring was carried out in the same manner as in Example 1 except that 5 parts by mass of IRGACURE (registered trademark) 184 and 3 parts by mass of IRGACURE 819 (manufactured by CIBA. SPECIALTY. CHEMICALS) were used as a photopolymerization initiator. Resin composition. Using the photocurable resin composition, a laminate of a cured film and a base film was obtained in the same manner as in Example 1. The pencil hardness and the bendability of the obtained laminated body were measured in Table 3.

[Examples 11 to 17]

The amount of the reactive urethane polymer, the triazine-based ultraviolet absorber, and the photopolymerization initiator was changed to the amount shown in Table 3, respectively. In the same manner as in Example 1, except that the laminate of the cured film and the base film was obtained. The results of measuring the pencil hardness and the bendability of the obtained laminate were shown in Table 3.

In the same manner as in the first embodiment, the layered system has a small amount of change in the YI value and excellent light resistance.

[Embodiment 18]

Since the laminated system obtained in each of Examples 1 to 17 has excellent flexibility and hardness, the laminated body obtained by adding a functional layer to the laminated body can exhibit sufficient flexibility and hardness.

(industrial use possibility)

The photocurable resin composition of the present invention and a method for producing a cured film or a laminate using the same can be used for producing a hard coat film having ultraviolet absorbing properties, and the hard coat film can be provided, for example, on a plasma display. On the display screen of an electronic image display device such as a device (PD) or a liquid crystal display (LCD).

10‧‧‧Substrate film

10a‧‧‧Main surface of the substrate film

20‧‧‧ hardened film

30‧‧‧Layered body

Claims (14)

A photocurable resin composition containing a difunctional or higher polyfunctional (meth) acrylate, a reactive urethane polymer, a photopolymerization initiator, and an ultraviolet absorber. The photocurable resin composition according to claim 1, wherein the reactive urethane polymer comprises: a urethane polymer having a main chain belonging to a polyurethane chain and a (meth) acrylate group bonded to the end of the main chain; or a urethane-modified (meth) acrylate resin having a main chain of a (meth)acrylic resin bonded to the main chain and a side chain containing a polyurethane chain and a (meth) acrylate group bonded to the end of the side chain; or a combination thereof. The photocurable resin composition according to the first or second aspect of the invention, wherein the reactivity is 100 parts by mass based on the total of the polyfunctional (meth)acrylate and the reactive urethane polymer. The content of the urethane polymer is 10 to 50 parts by mass. A laminated body comprising: a base film; and a cured film which is laminated on at least one side of the base film, and is composed of a photocurable resin according to any one of claims 1 to 3. Hardened matter. The laminate according to the fourth aspect of the invention, wherein the laminate having a width of 1 cm and a length of 8 cm is wound around a roll having a diameter of 6 mm as the inner side, and the crack generated in the cured film is 4 or less. The laminate according to claim 4, wherein the laminated film having a width of 1 cm and a length of 8 cm is formed by using the cured film as the outer side. When wound around a roll having a diameter of 6 mm, the number of cracks generated in the cured film was four or less. The laminated body according to any one of claims 4 to 6, wherein the laminated body having a width of 1 cm and a length of 8 cm is wound around a roll having a diameter of 2 mm as the inner side of the cured film, and is hardened as described above. The crack generated by the film was 4 or less. The laminated body according to any one of claims 4 to 7, wherein the laminated body having a width of 1 cm and a length of 8 cm is wound around a roll having a diameter of 2 mm by the hardened film as the outer side, and is hardened as described above. The crack generated by the film was 4 or less. The laminate according to any one of claims 4 to 8, wherein the laminate system has a pencil hardness of 4B or more. The laminate according to any one of claims 4 to 9, wherein the laminate system has a pencil hardness of HB or more. The laminate according to claim 9 or 10, wherein the laminate system has a pencil hardness. The laminate according to any one of claims 4 to 11, further comprising a functional layer different from the cured film. A method of producing a laminate comprising the steps of forming a composition layer of the photocurable resin composition according to any one of claims 1 to 3 on one side of a substrate film, And the step of curing the composition layer by exposing the composition layer to form a cured film. The method of claim 13, wherein the substrate film is a polyimide film.