JP2002069139A - Active energy ray-curable resin composition - Google Patents

Abstract

(57) [Summary] (Modified) [Problem] An active energy ray-curable resin having excellent shape retention characteristics and curl resistance required for sheet-shaped optical articles and excellent physical properties such as transparency and surface hardness. Provision of a composition. An activity comprising a urethane (meth) acrylate (A) having three (meth) acryloyl groups in a molecule and a (meth) acrylate (B) having three (meth) acryloyl groups in a molecule. An energy ray-curable resin composition, wherein (A) is obtained by reacting a compound having three isocyanate groups with a compound represented by the general formula (1) or (2). An active energy ray-curable resin composition, wherein a cured product of the composition does not have a yield point in a diagram showing the relationship between tensile stress and strain. (Wherein, R 1 represents H or a methyl group, and R 2 and R 3 may have a substituent or may be branched and may have C2-8
Represents an alkylene chain. )

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a backlight (back light source) of a translucent display such as a transmissive liquid crystal display device, a video projector, an advertising board, a light diffusing plate, and a back reflection lens. As an optical article having a prism action or a lens action such as a lens array sheet,
Or, a planar optical article such as a lenticular lens or a Fresnel lens constituting a screen of a projection television, a pickup lens for reading an optical disk signal,
Camera lenses for video cameras, still cameras, etc., CR
The present invention relates to an active energy ray-curable resin composition for an optical article used for an optical element having a structure in which a molded layer made of a resin cured product is provided on a substrate, such as an optical element for preventing irregular reflection on the surface of a liquid crystal display element.

[0002]

2. Description of the Related Art In recent years, as optical devices have become smaller and lighter, optical elements having fine and complicated uneven surface shapes, lenses having ultra-high precision flat or aspheric surface shapes,
The need for prisms and mirrors is increasing. In particular, in the case of transmissive liquid crystal display elements, the demand for lighter weight and lower power consumption is further increased, and in order to effectively utilize the light energy of the back light source, the desired output light diffusion angle, emission direction, and peak BACKGROUND ART Sheet-shaped optical articles for obtaining directional luminance have been used. With the sheet-shaped optical article, the required characteristics as described above are becoming more severe as the screen of the transmissive liquid crystal display element becomes larger. As a method for manufacturing these optical elements, various methods using an energy ray-curable resin composition have been proposed.

Such an optical element is generally excellent in shape retention characteristics such as shape retention force and restoring force of an optical resin layer, and is excellent in durability because it needs to withstand long-term use. Is required. In the case where the molded product is in the form of a sheet, warpage and optical distortion often occur, and it is required that the molded product does not undergo deformation such as dent due to bending or pressing. In particular, an optical article in which a sheet-shaped optical article is warped due to the enlargement of the screen of the liquid crystal display element, that is, causes a so-called curl phenomenon, is likely to cause a problem in a process of assembling the liquid crystal display element.

[0004] Many methods have been proposed to improve the various problems as described above.
As a proposal focusing on the structure of the resin material and the number of functional groups in the energy ray-curable resin composition to be used, a method using a specific high molecular weight energy ray-curable oligomer resin composition, for example, JP-A-62-258401 In the gazette, a di-isocyanate and a (meth) acrylate having a hydroxyl group in a molecule are reacted with a polyester oligomer obtained by reacting a polybasic acid and a polyhydric alcohol, and a 2- to 4-functional urethane-modified polyester (meth) is obtained. Cured resin obtained by curing an active energy ray-curable resin composition containing an acrylate oligomer, a trifunctional (meth) acrylate, and a monofunctional (meth) acrylate on a base material such as glass using active energy rays such as ultraviolet rays. An optical element provided with a layer is disclosed in Japanese Patent Application Laid-Open No. 4-31414.
In the publication, a reactive oligomer having a polyester structure and a urethane bond having two or more polymerizable unsaturated bonds, a monomer having two polymerizable unsaturated bonds, and a monomer having three or more polymerizable unsaturated bonds are referred to. A method using a contained active energy ray-curable resin composition for optics is disclosed.

[0005] However, when an optical article is actually manufactured, the curl resistance and the shape retention described above cannot be satisfied even with these conventional methods for manufacturing an optical article.

To solve these problems, Japanese Patent Application Laid-Open No. 9-616
No. 01 discloses a method of using an energy ray-curable resin composition in which the cured product does not have a yield point in a relationship diagram between the tensile stress and the strain of the cured product, which causes insufficient shape retention of the cured product. Improvements have been made in terms of plastic deformation called "place marks" and curl resistance. However, in the described resin material, there is no idea to control the crosslink density of the cured product by focusing on the number of functional groups of the (meth) acrylate and the distance between the functional groups. It was not possible to satisfy the stricter requirements for more strict shape retention characteristics in a large sheet optical article.

[0007]

[Problems to be solved by the invention]

The problem to be solved by the present invention is that the above-mentioned sheet-shaped optical article is excellent in curl resistance and shape retention properties, and has good physical properties such as transparency and surface hardness. An object of the present invention is to provide an active energy ray-curable resin composition for an optical article, which is short in productivity and can improve productivity.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that acryloyl groups have been reduced to 3
Energy ray curable resin whose cured product has no yield point by controlling the crosslink density of the cured product by using urethane (meth) acrylate having three acryloyl groups in the molecule and urethane (meth) acrylate having three acryloyl groups in the molecule By using the composition, it is possible to obtain the conventional compositions described in JP-A-62-258401, JP-A-4-31414 and JP-A-9-616.
The active energy ray-curable resin composition for an optical article disclosed in No. 01 satisfies the curl resistance and shape retention characteristics that were difficult with the transparent resin, and found that the transparency and the surface hardness were excellent. The present invention has been completed.

[0010]

DETAILED DESCRIPTION OF THE INVENTION That is, the present invention relates to (I) a urethane (meth) having three (meth) acryloyl groups in a molecule.
An active energy ray-curable resin composition comprising an acrylate (A) and a (meth) acrylate (B) having three (meth) acryloyl groups in the molecule, wherein the (meth) acryloyl group is in the molecule. Urethane (meth) acrylate (A) having three is obtained by reacting a trifunctional isocyanate compound with a compound represented by the general formula (1) or (2), and a cured product of the composition Is to provide an active energy ray-curable resin composition characterized by having no yield point in the relationship between tensile stress and strain, and the present invention provides

Embedded image (Wherein, R1 represents a hydrogen atom or a methyl group;
R3 represents an alkylene chain having 2 to 8 carbon atoms which may have a substituent or may be branched, m and n are each independently, m is an integer of 1 to 10, and n is 0 to 0 It is an integer of 10. In the formula (2), [] indicates a block-like or random chain. (II) In the graph showing the relationship between tensile stress and strain, the cured product of the composition shows the stress at break (σ2) and the intersection of the tangent line at the initial tensile deformation point and the stress at the strain at break (σ1). Ratio (σ2 / σ1) is 0.5
The present invention provides the active energy ray-curable resin composition as described in (I) above, and the present invention provides (III) wherein the sum (m + n) of m and n in the general formula (1) is 2 to 5 The present invention also provides an active energy ray-curable resin composition according to (I) or (II), wherein the (IV) has three (meth) acryloyl groups in the molecule. The active energy ray-curable type according to (I), (II) or (III), wherein the acrylate (B) has a structure in which three (meth) acrylic acids are bonded to a compound containing a hydroxyl group by an esterification reaction. The present invention provides a resin composition.

Hereinafter, the present invention will be described in detail. In the active energy ray-curable resin composition for an optical article of the present invention for the above-mentioned problems, it is essential that a cured product of the composition does not have a yield point in a diagram showing a relationship between tensile stress and strain.

That is, in the optical article comprising the specific active energy ray-curable resin composition of the present invention, since the cured product does not have a yield point in a stress-strain curve, the applied stress is within the elastic limit. In some cases, when released from the stress, the shape is restored to the original shape by the elastic restoring force, and no deformation occurs.

The sheet-shaped optical article may be locally deformed by an external force during the manufacturing process or when the sheet-shaped optical article is incorporated into an apparatus. For example, when a sheet-like optical article is wound up with foreign matter or bubbles interposed therebetween, a large stress is locally applied to a portion where the foreign matter exists. In some cases, a sheet winding roll or a large number of sheet-shaped optical articles may be stored in a stacked state. In these cases, the stress is locally concentrated by its own weight. In this case, the local deformation may remain as distortion and may remain even after being released from the stress. This is due to excessive stress on the optical article,
This is probably because plastic deformation occurs.

In particular, this plastic deformation cannot be completely eliminated merely by controlling the elastic modulus, and the occurrence of plastic deformation is related to the presence or absence of a yield point in a tensile stress-strain curve, and the yield point is determined. The cured product using the active energy ray-curable resin composition for an optical article according to the present invention does not generate plastic deformation, and a good product can be obtained.

FIGS. 1 to 3 show the measurement of JIS K7113.
Measured at a temperature of 23 ± 2 ° C and a relative humidity of 50 ± 2% according to the method.
The relationship between tensile stress (Pa) and strain (%)
This is shown in FIG. Strain (%) is the length of the sample after tension
(L) and the length of the initial sample (l ₀) And the difference of the initial sample
Length (l₀), And the percentage is shown as a percentage.
And distortion (%) = [(l−l₀) / L₀ ] X 100
Is what is done.

In the present invention, the fact that the cured product does not have a yield point means that the relationship between tensile stress (Pa) and strain (%), that is,
In a tensile stress-strain curve of a cured product, or a relational diagram generally called an SS (stress-strain) curve or SS characteristic, for example, without a yield point as shown in FIG. Say something like Furthermore,
As shown in FIG. 3, even when the yield point does not exist, the stress at break (σ 2) is the value of the intersection (σ 1) between the tangent at the initial tensile deformation point and the stress at strain at break on the tensile stress-strain curve. The ratio, that is, (σ2 / σ1), is particularly preferably a value of 0.5 or more in order to shorten the time required for restoring the cured product after removing the external force.

Next, the active energy ray-curable resin composition for an optical article according to the present invention, which solves the above-mentioned problems, has a cured product of the above-mentioned composition which does not have a yield point in the relationship between tensile stress and strain. It is difficult to solve it alone.

As a means for improving the characteristics of a sheet-shaped optical article, which is required to have a stricter shape-retaining force, as the size of a transmission-type liquid crystal display device increases, a hydrogen bond is formed to exhibit excellent cured physical properties. Urethane (meta)
It is essential to precisely control the number of functional groups and the distance between the functional groups of the acrylate and the (meth) acrylate used simultaneously to control the crosslink density and physical properties of the cured product. That is, an active energy ray-curable resin for optical articles comprising a urethane (meth) acrylate having three (meth) acryloyl groups in the molecule and a (meth) acrylate having three (meth) acryloyl groups in the molecule It must be a composition.

The resin composition of the present invention contains substantially no monofunctional or bifunctional reactive diluent as a component of the composition, and is composed of two different specific compounds having three polymerization functional groups. Therefore, the distance between cross-linking points and the cohesion between molecules due to hydrogen bonding can be precisely controlled. Therefore, it is possible to impart high shape retention characteristics while suppressing the curl phenomenon of the cured product.

Specifically, a urethane bond contained in the compound having three acryloyl groups used in the present invention forms a hydrogen bond, and the hydrogen bond formed between the molecules increases the cohesive force between the molecules. As a result, the curing speed is increased, and the physical strength is further increased.

The urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule used in the present invention is, for example, a trifunctional isocyanate compound represented by the general formula (1) or (2). And a compound obtained by reacting the compound.

Embedded image (Wherein, R1 represents a hydrogen atom or a methyl group;
R3 represents an alkylene chain having 2 to 8 carbon atoms which may have a substituent or may be branched, m and n are each independently, m is an integer of 1 to 10, and n is 0 to 0 It is an integer of 10. In the formula (2), [] indicates a block-like or random chain. )

In the brackets [] of the formula (2), the number of carbon atoms is 2-8.
An oxyalkylene chain having a block structure or a random structure comprising an alkylene chain of

Particularly typical examples of trifunctional isocyanate compounds include, for example, triphenylmethane triisocyanate and tris as described in "Polyurethane Resin Handbook (edited by Keiji Iwata, Nikkan Kogyo Shimbun)". (Isocyanate phenyl) thiophosphate, lysine ester triisocyanate, 2-isocyanate ethyl-2,6-diisocyanate caproate, 1,6,11-undecane triisocyanate,
1,8-diisocyanate-4-isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate and the like, and tolylene diisocyanate described in the above-mentioned reference, 4,4 ' -Diphenylmethane diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, p-phenylene diisocyanate, transcyclohexane 1, 4-diisocyanate, lysine diisocyanate, tetramethylxylene diisocyanate, trimethylhexamethylene diisocyanate, etc. Aromatic, aliphatic, compounds obtained by trimerizing an alicyclic diisocyanate compound, for example, diisocyanate biuret type polyisocyanate, such as isocyanurate type polyisocyanate of diisocyanate. Further, a compound having an average number of isocyanate groups of 3 among polyisocyanate compounds having a phenylisocyanate skeleton, which is referred to as a high molecular weight MDI composed of a mixture of polynuclear substances having several types of structures, can also be used.

Examples of the compound represented by the above general formula (1) or (2) include (meth) acrylate compounds having a hydroxyl group in the molecule. Specifically, particularly representative examples are 2-vidroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, and polypropylene glycol mono. (Meth) acrylate compounds having a single structure oxyalkylene chain, such as (meth) acrylate and polyethylene glycol mono (meth) acrylate; polyethylene glycol-polypropylene glycol mono (meth) acrylate, polyoxybutylene-polyoxypropylene mono (meth) (Meth) acrylate compounds having an oxyalkylene chain having a block structure such as acrylate; poly (ethylene glycol-tetramethylene glycol) mono (meth) acrylate, poly ( B propylene glycol - tetramethylene glycol) mono (meth) having an oxyalkylene chain of a random structure of acrylate (meth) acrylate; ring-opening reaction product of ε- caprolactone with hydroxyethyl (meth) acrylate.

In the compound represented by the general formula (1) or (2), the distance between the functional groups in the urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule of the present invention is defined as In order to control, the length of the hydroxyl group and the (meth) acryloyl group in the compound represented by the general formula (1) or (2) is controlled. In this case, the number of repeating units represented by m + n in the general formula (1) suppresses the curl phenomenon due to an increase in the crosslink density, and reduces the hardness due to an extreme decrease in the crosslink density or balances various properties due to the appearance of a yield point. In order to suppress the deterioration of, the number is preferably 2 or more, and particularly preferably 2 to 5.

A urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule used in the present invention is a compound having three isocyanate groups and a (meth) acrylate compound having a hydroxyl group in the molecule. When it is obtained by the reaction, the equivalent ratio (OH / NCO) of the isocyanate group (NCO) in the compound having three isocyanate groups to the hydroxyl group (OH) of the (meth) acrylate compound having a hydroxyl group in the molecule is 1. In the range of 0 to 1.2,
It is obtained by reacting at a reaction temperature of 60 to 100 ° C. In this case, various urethanization catalysts may be used.

The (meth) acrylate (B) having three (meth) acryloyl groups in the molecule used in the present invention has a structure in which three (meth) acrylic acids are bonded to a compound containing a hydroxyl group by an esterification reaction. Is preferred, and
Particularly typical examples include trimethylolpropane, glycerin, pentaerythritol, trimethylolethane, tris (2-hydroxyethyl) isocyanurate, tris (hydroxypropyl) isocyanurate tri (meth) acrylate compound; trimethylol Propane, glycerin, pentaerythritol, trimethylolethane, tris (2-hydroxyethyl) isocyanurate, tris (hydroxy) isocyanurate, a tri (meth) acrylate compound of a hydroxyl group-containing compound obtained by adding 1 to 20 mol of ethylene oxide to ethylene oxide Trimethylolpropane, glycerin, pentaerythritol, trimethylolethane, tris (2-hydroxyethyl) isocyanurate, tris (hydroxypropyl) isocyanate Tri (meth) acrylate compound of a hydroxyl group-containing compound obtained by adding 1 to 20 mol of propylene oxide to nurate; trimethylolpropane, glycerin, pentaerythritol, trimethylolethane, tris (2-hydroxyethyl) isocyanurate, tris (hydroxy) (Propyl) isocyanurate to which 1 to 20 mol of ε-caprolactone is added, and a hydroxyl group-containing compound tri (meth) acrylate compound.

The urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule used in the present invention is capable of forming a hydrogen bond and exhibiting excellent cured physical properties. ) An acrylate is used to form a cured resin layer having toughness and environmental resistance properties on the obtained cured resin layer, and usually 10 to 9 in the active energy ray-curable resin composition of the present invention.
0% by weight, preferably 20 to 80% by weight.

In the present invention, (meth) is used in the molecule.
The (meth) acrylate (B) having three acryloyl groups is used to control the number of functional groups of the (meth) acrylate and the distance between the functional groups in the same manner as the above-mentioned component (A). This is for controlling the viscosity of the energy ray-curable resin composition to an appropriate value, and is usually contained in the active energy ray-curable resin composition of the present invention in an amount of 10 to 90% by weight, preferably 20 to 80% by weight. be able to.

In the present invention, an active energy ray is used for the curing reaction. As the active energy rays, visible rays, ultraviolet rays, electromagnetic waves such as X-rays, or charged particle rays such as electron beams are used. Of these, visible rays, ultraviolet rays, or electron rays are often used practically. It is. In particular, when the resin preparation and the resin composition of the present invention are cured using visible light or ultraviolet light, the wavelength is preferably 1,0.
A photopolymerization initiator that dissociates and generates radicals by ultraviolet light or visible light having a wavelength of 00 to 8,000 angstroms should be used.

As such a photopolymerization initiator, a photopolymerization initiator capable of dissociating by light to generate a radical can be used, and such a photopolymerization initiator can be used.
Typical examples of the photopolymerization initiator used in the present invention include benzophenone and 3,3-dimethyl-4-.
Methoxybenzophenone, 4,4'-bisdimethylaminobenzophenone, 4,4'-bisdiethylaminobenzophenone, 4,4-dichlorobenzophenone, Michler's ketone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) Benzophenones such as benzophenone; xanthone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone,
2,4-dimethylthioxanthone, thioxanthone-4-
Xanthones and thioxanthones such as sulfonic acids; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, benzoin butyl ether and other acyloin ethers; α-diketones such as benzyl and diacetyl Sulfides such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide and p-tolyl disulfide; 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoate And benzoic acids such as butyl acid, 4-dimethylaminobenzoic acid-2-ethylhexyl, and 4-dimethylaminobenzoic acid-2-isoamyl.

In addition, 3,3'-carbonyl-bis (7-diethylamino) coumarin, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2
2-diphenylethan-1-one, 2-methyl-1-
[4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-hydroxy-2 -Methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane- 1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-
On, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 4-benzoyl-4
'-Methyldimethylsulfide, 2,2-diethoxyacetophenone, benzyldimethylketal, benzyl-
β-methoxyethyl acetal, 1-phenyl-1,2
-Propanedione-2- (o-ethoxycarbonyl) oxime, 2-phenyl-1,2-butanedione-2-
(O-methoxycarbonyl) oxime, 1,3-diphenyl-propanetrione-2- (o-ethoxycarponyl) oxime, 1-phenyl-3-ethoxy-propanetrione-2- (o-benzoyl) oxime, o-benzoyl Methyl benzoate, bis (4-dimethylaminophenyl) ketone, p-dimethylaminoacetophenone,
α, α-dichloro-4-phenoxyacetophenone, pentyl-4-dimethylaminobenzoate, 2- (o-
Chlorophenyl) -4,5-diphenylimidazolyl dimer, 2,4-bis-trichloromethyl-6- [di-
(Ethoxycarbonylmethyl) amino] phenyl-S-
Triazine, 2,4-bis-trichloromethyl-6-
(4-ethoxy) phenyl-S-triazine, 2,4-
Bis-trichloromethyl-6- (3-bromo-4-ethoxy) phenyl-S-triazineanthraquinone, 2-t
-Butyl anthraquinone, 2-amyl anthraquinone,
β-chloroanthraquinone and the like.

As the photo (polymerization) initiator, commercially available products can also be used. For example, Irgacure-184, 1
49, 261, 369, 500, 651, 7
84, 819, 907, 1116, 1664,
1700, 1800, 1850, 2959, 4043, Darocur-1173 (manufactured by Ciba Specialty Chemicals), Lucirin TPO (manufactured by BASF), KAYACU
RE-DETX, MBP, DMBI, EPA, OA (Nippon Kayaku Co., Ltd.), VICURE-10, 55 (STAUFFER Co. LTD)
Made), TRIGONALP1 (AKZO Co. LTD), SANDORY 1000
(Made by SANDOZ Co.LTD), DEAP (made by APJOHN Co.LTD), QUAN
TACURE-PDO, ITX, EPD (WARD BLEKINSOP Co.LTD
Manufactured).

Various photosensitizers can be used in combination with such a photopolymerization initiator. Typical examples of the photosensitizer used in the present invention include amines, ureas, sulfur-containing compounds, phosphorus-containing compounds, chlorine-containing compounds, nitriles, and other nitrogen-containing compounds.

These can be used alone or in combination of two or more. The amount used is not particularly limited, but is preferably 0.01 to 20 with respect to the photopolymerizable monomer in the composition in order to maintain good sensitivity, suppress precipitation of crystals, and maintain good coating film properties. % By weight, more preferably 0.1 to 1
It can be used so as to contain 0% by weight.

Among these, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-
Hydroxyethoxy) phenyl] -2-hydroxy-2
-Methyl-1-propan-1-one, thioxanthone and thioxanthone derivatives, 2,2-dimethoxy-1,
2-diphenylethan-1-one, 2,4,6-trimethylbenzoyldiphenoylphosphine oxide, 2
-Methyl-1- [4- (methylthio) phenyl] -2-
Since one or a mixture of two or more kinds selected from the group of morpholino-1-propanone and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one has high curability, Particularly preferred.

In the production of an optical article using the active energy ray-curable resin composition for an optical article of the present invention, active energy rays such as ultraviolet rays are often irradiated through a transparent substrate surface serving as a support. . In this case, the photoinitiator that can be used is preferably an initiator having an absorption ability in a long wavelength region, and it is desirable to use a photoinitiator having a photoinitiation ability in the range of 360 nm to 450 nm of ultraviolet rays. 45
Those that absorb light of 0 nm or more have poor stability of the composition, require production in a completely light-shielded environment, and are extremely difficult to handle.

When an electron beam is used, these photoinitiators and photosensitizers are unnecessary.

The active energy ray means an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or cross-linking a molecule. Usually, an ultraviolet ray, an electron beam or the like is used. Ultra high pressure mercury lamp, high pressure mercury lamp,
Low pressure mercury lamp, carbon arc, black light lamp,
A light source such as a metal halide lamp can be used.
As the ultraviolet wavelength, a wavelength range of usually 1900 to 3800 angstroms is mainly used.

In the case of an electron beam, an irradiation source such as a Cockloft-Walton type, a bandeograph type, a resonance transformer type, an insulating core transformer type, or various electron beam accelerators such as a linear type, a dynamitron type and a high frequency type. Can be used, and 100 to 1000 KeV, preferably 100
Irradiate with electrons with energy of ~ 300 KeV. The irradiation dose is usually preferably about 0.5 to 30 Mrad.

The active energy ray-curable resin composition of the present invention is naturally excellent in transparency. Thickness 0.
The light transmittance of the cured product of 3 mm in the wavelength region of 400 to 900 nm is at least 80% or more, preferably 85% or more.
%, More preferably 90% or more. Also, if necessary, in the resin composition, in order to improve the coating properties and coating suitability, and to improve the releasability from the mother mold, various additives include an ultraviolet absorber, a light stabilizer, and an antioxidant. ,
Rheology control agent, silicone additive, defoamer,
It is also possible to add a release agent, an antistatic agent and the like.

The active energy ray-curable resin composition of the present invention can be used for a transmission type liquid crystal display device, a video projector,
For example, as an optical article having a prism action or a lens action, such as a lens array sheet, used for a translucent display backlight (back light source) such as an advertising board, a light diffusion plate, and a rear reflection lens, or a projection television. Planar optical articles such as lenticular lenses and Fresnel lenses that compose screens, pickup lenses for reading optical disk signals, camera lenses such as video cameras and still cameras, CRTs, optical elements for preventing irregular reflection on the surface of liquid crystal display elements, etc. It is a material suitable for various optical articles used for an optical element having a structure in which a fine optical molding layer such as a lens pattern made of a cured resin is provided on a transparent base material, and is suitably used for a sheet-shaped optical article. In addition, depending on the application, even when a transparent substrate having another shape such as a film shape or a plate shape is used, it can be similarly used for various optical articles used for an optical element having a structure provided with a fine optical molded layer. it can.

For these optical articles, for example, the active energy ray-curable resin composition of the present invention is applied on a matrix having a required fine shape to form the active energy ray-curable resin composition layer. After being formed, a transparent substrate serving as a support is adhered onto the layer, and then the resin composition is cured by irradiating active energy rays from the transparent substrate surface in that state, and then separated from the matrix. It is manufactured by

Examples of the sheet-like, film-like, and plate-like transparent base materials usable herein include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), triacetyl cellulose, polycarbonate resins, and the like. Examples include acrylic resin such as methyl methacrylate copolymer, styrene resin, polysulfone resin, polyether sulfone resin, polycarbonate resin, vinyl chloride resin, polymethacrylimide resin, and glass.

[0045]

Next, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention should not be limited to these. All parts and percentages in the examples are based on weight unless otherwise specified.

Synthesis Example 1 A ring-opening reaction product of ε-caprolactone and hydroxyethyl acrylate (OH value = 16) was placed in a flask equipped with a thermometer, a stirrer, and a condenser.
660 parts of 3KOH-mg / Kg, m + n = 3 in the general formula (1) were charged, and the temperature was raised to 60 ° C. with stirring, and a buret type polyisocyanate of hexamethylene diisocyanate (NCO% = 23.3%) 340 parts was added and reacted over 1 hour while paying attention to heat generation. The reaction was carried out for 10 hours, and it was confirmed from the infrared absorption spectrum that the absorption of the isocyanate group had disappeared. Thus, a target urethane acrylate having three acryloyl groups (A-1) was obtained.

Synthesis Example 2 A ring-opened reaction product of ε-caprolactone and hydroxyethyl acrylate (OH value = 12) was placed in a flask equipped with a thermometer, a stirrer, and a condenser.
727 parts of 3KOH-mg / Kg, m + n = 4 in the general formula (1) were charged, and the temperature was raised to 60 ° C. with stirring, and the isocyanurate-type polyisocyanate of hexamethylene diisocyanate (NCO% = 23.8%) 273 parts were added and reacted over 1 hour while paying attention to heat generation. The reaction was carried out for 10 hours, and it was confirmed by infrared absorption spectrum that the absorption of the isocyanate group had disappeared.
Urethane acrylate (A-2) was obtained.

(Comparative Synthesis Example 1) A flask equipped with a thermometer, a stirrer, and a condenser was charged with 444 parts of isophorone diisocyanate, the temperature was raised to 60 ° C with stirring, and 1,6-hexanediol and adipine were added. 2200 parts of an acid polyester diol (OH value = 51 KOH-mg / Kg) was added and reacted over 1 hour while paying attention to heat generation. The reaction was carried out for 10 hours, after which 232 parts of hydroxyethyl acrylate were added and the reaction was carried out for another 10 hours. It was confirmed from the infrared absorption spectrum that the absorption of the isocyanate group had disappeared, and a desired urethane acrylate (HA-1) having two acryloyl groups was obtained.

(Examples 1 to 4)
An active energy ray-curable resin composition for optical articles was prepared. Next, the obtained active energy ray-curable resin composition is put between a mold having a repeating chevron shape having a width of 120 μm and a height of 100 μm and a transparent PET film (single-sided corona discharge treatment) as a transparent substrate. Then, ultraviolet rays of 800 mJ / cm2 were irradiated with an ultra-high pressure mercury lamp to cure. After ultraviolet curing, the transparent PET film was peeled off from the mold together with the active energy ray-curable resin layer to produce an optical article having a required shape transferred.

The obtained active energy ray-curable resin composition was applied on a clean and smooth glass plate to a thickness of about 300 μm, and cured by irradiating an ultraviolet ray of 500 mJ / cm 2 with an ultra-high pressure mercury lamp. . The cured smooth resin layer was peeled off from the glass plate to obtain a sample for measurement of light transmittance and tensile modulus.

Further, the obtained active energy ray-curable resin composition was applied on a transparent PET film to a thickness of about 20 μm, and was cured by irradiating it with an ultraviolet ray of 500 mJ / cm 2 by an ultra-high pressure mercury lamp. This was used as a sample for the sex test.

Using these optical articles, the following measurements
Evaluation was performed according to the test method. Table 2 shows the evaluation results. (1) Curability: 15 c with a high-pressure mercury lamp of 160 W / cm
When irradiation was performed at a lamp height of m and a line speed of 10 m / min, the number of irradiations until the surface tack-free was measured. The smaller the number of irradiations, the better the curability.
Those that became tack-free below the pass were rated as ○, and those that required more irradiation were rated as x. (2) Light transmittance: Using the prepared test piece having a thickness of 300 μm, the light transmittance in the wavelength region of 400 to 900 nm was measured. However, those less than that were marked as x. (3) Plate releasability: When forming a shaped optical article using a transparent PET film, a mark indicates that the sheet can be formed without a large load at the time of peeling; A mark that caused a peeling mark or a peeling mark was evaluated as x. (4) Judgment of initial appearance: The appearance after forming the shaped optical article was visually judged. Judgment criteria were as follows: those with a uniform lens surface shape were obtained, those with cracks or missing shapes were seen as partial, and those with cracks or missing shapes were seen as x. did. (5, 6) Yield point judgment and elasticity evaluation: created thickness 30
A test piece of 0 μm was punched out using a super dumbbell manufactured by Dumbbell Co., Ltd. (JIS 71113 No. 2 dumbbell) to form a measurement sheet, and the tensile modulus was measured.
However, at the time of measurement, in order to prevent the measurement sheet from slipping with the chuck, the right, left, top and bottom four places outside the space between the mark lines (25 mm) are 0.3 mm in thickness, 20 mm in length and width, and an adhesive (Toa Gosei Chemical Co., Ltd.) Using Aaron alpha)
It was a grip. The testing machine used Tensilon manufactured by Toyo Baldwin Co., with a deformation speed of 1.0 mm / min.
The measurement was performed in an atmosphere at 25 ° C. and a relative humidity of 50%.

The yield point is determined from each of the SS curves.
In the table, a pattern having no yield point in the present invention as shown in FIGS. 1 and 3 is shown as A, and a pattern having a yield point as shown in FIG. 2 is shown as B. The tensile modulus was calculated from the slope of the SS curve (stress-strain curve) drawn from the starting point of tensile deformation (the number of measurements was five, and the average value was used). The elasticity evaluation (σ2 / σ1) is calculated from the SS curve of the pattern as shown in FIG.
σ2 and σ1 were read and σ2 / σ1 was calculated. (7) Curling resistance: A cured test product having a cured resin layer having a smooth surface and a thickness of 20 μm was prepared using a transparent PET film, and a 70 mm × 20 mm strip-shaped test piece was prepared. The end 5 mm of this test piece was fixed on a glass substrate with an adhesive tape, and heated at a temperature of 100 ° C. for 4 hours. After returning to room temperature, the distance between the other end and the glass substrate was measured. The case where the distance was 0.5 mm or less was evaluated as ○, and the case where the distance was more than 0.5 mm was evaluated as ×. (8) Shape retention characteristics: A 30-mm × 30-mm cut sheet-shaped optical article having a shape formed using a transparent PET film on a smooth metal plate at a temperature of 25 ° C., and an active energy ray-curable resin layer is formed on the top. , And a cylindrical indenter (diameter: 2 mm) having a flat contact surface was placed thereon, and a load of 1 kg was applied for 20 minutes. Subsequently, the load was removed, and each sheet-shaped optical article was visually inspected by a fluorescent lamp or reflected light for the presence or absence of deformation marks. The criterion for the shape retention force is that the trace of the sheet's deformation trace cannot be confirmed within 2 minutes. ◎ The trace of the sheet's trace trace cannot be confirmed within 5 minutes. ○ A mark where deformation traces could be confirmed was evaluated as x.

Comparative Examples 1 to 3 Active energy ray-curable resin compositions for comparison and control were prepared according to the formulations shown in Table 1.
For this, an optical article for evaluation and a cured product for test were produced in the same manner as in Examples 1 to 5. Table 2 shows the results of comparative evaluation performed in the same manner as in the examples.

[0055]

[Table 1] PO3-TMPTA: triacrylate compound of a hydroxyl group-containing compound obtained by adding 3 mol of propylene oxide to trimethylolpropane EO15-TMPTA: triacrylate compound of a hydroxyl group-containing compound obtained by adding 15 mol of ethylene oxide to trimethylolpropane TMPTA: trimethylol Propane triacrylate compound NPGDA: Neopentyl glycol diacrylate compound DPHA: Dipentaerythritol hexaacrylate compound TPGDA: Tripropylene glycol diacrylate compound

[0056]

[Table 2]

[0057]

According to the present invention, an optical material which satisfies the curl resistance and shape retention characteristics required for a sheet-shaped optical article, is excellent in transparency, surface hardness, etc., has a short curing time, and is excellent in productivity. An active energy ray-curable resin composition for articles can be provided.

[Brief description of the drawings]

FIG. 1 shows the relationship between tensile stress (Pa) and strain (%) (SS)
(Curve). The vertical axis is the tensile stress (Pa),
The horizontal axis represents strain (%). (This is a pattern where no yield point is seen.)

FIG. 2 shows the relationship between tensile stress (Pa) and strain (%) (SS)
(Curve). The vertical axis is the tensile stress (Pa),
The horizontal axis represents strain (%). (This is a pattern where the yield point can be seen.)

FIG. 3 shows the relationship between tensile stress (Pa) and strain (%) (SS)
(Curve). The vertical axis is the tensile stress (Pa),
The horizontal axis represents strain (%). (This is a pattern where no yield point is seen.)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J011 AA05 AC04 BB01 QA04 QA23 QA24 QA25 QA33 QA38 QA39 QB15 QB24 SA05 SA06 SA07 SA22 SA24 SA25 SA26 SA27 SA32 SA34 SA42 SA54 SA61 SA63 SA64 SA65 SA78 SA82 SA83 SA84 UA01 UA01 VA03 WA07 WA10 4J027 AB10 AB28 AB32 AB34 AC03 AC04 AC06 AC08 AG03 AG04 AG12 AG23 AG24 AG28 AJ02 AJ08 AJ09 BA01 BA23 BA24 BA25 BA26 CB10 CC04 CC05 CC06 CC08 CD04 CD05 4J100 AL63Q AL67P AL67Q BA02P BA08P BA08P BA21PBABC BCBCBAP CA04 JA32 JA33 JA36

Claims (4)

[Claims] 1. An urethane (meth) acrylate (A) having three (meth) acryloyl groups in a molecule and a (meth) acrylate (B) having three (meth) acryloyl groups in a molecule. An active energy ray-curable resin composition having (meth) acryloyl groups in the molecule.
Urethane (meth) acrylate (A) is obtained by reacting a compound having three isocyanate groups with a compound represented by the general formula (1) or (2). An active energy ray-curable resin composition, wherein the cured product does not have a yield point in a relationship diagram between tensile stress and strain. Embedded image (Wherein, R1 represents a hydrogen atom or a methyl group;
R3 represents an alkylene chain having 2 to 8 carbon atoms which may have a substituent or may be branched, m and n are each independently, m is an integer of 1 to 10, and n is 0 to 0 It is an integer of 10. In the formula (2), [] indicates a block-like or random chain. ) 2. A graph showing the relationship between tensile stress and strain in the cured product of the composition, wherein the stress at break (σ2) and the intersection (σ1) between the tangent at the initial tensile deformation point and the stress at strain at break. )
The active energy ray-curable resin composition according to claim 1, wherein the ratio (σ2 / σ1) is 0.5 or more. 3. The sum of m and n in the general formula (1) (m + n)
The active energy according to claim 1 or 2, wherein
A line-curable resin composition. 4. A (meth) acrylate (B) having three (meth) acryloyl groups in the molecule, having a structure in which three (meth) acrylic acids are bonded to a compound containing a hydroxyl group by an esterification reaction. The active energy ray-curable resin composition according to claim 1, 2, or 3.