JP4993364B2 - Active energy ray-curable resin composition for optical articles - Google Patents

Description

  The present invention is used for a backlight (back light source) of a translucent display body such as a transmissive liquid crystal display element, a video projector, an advertising board, a light diffusing plate, and a rear reflection lens, for example, a prism function such as a lens array sheet. Or optical articles having a lens action, or planar optical articles such as lenticular lenses and Fresnel lenses constituting screens of projection televisions, pickup lenses for reading optical disc signals, camera lenses such as video cameras and still cameras 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 material is provided on a substrate, such as an optical element for preventing irregular reflection on the surface of a CRT or a liquid crystal display element.

  In recent years, with the miniaturization and weight reduction of optical devices, there is an increasing need for optical elements having fine and complex uneven surface shapes, and lenses, prisms, and mirrors having an ultra-high accuracy flat or aspheric surface shape. Yes. In particular, in the transmissive liquid crystal display element, demands for light weight and low power consumption are further increased. In order to effectively use the light energy of the back light source, a desired output light diffusion angle, emission direction, peak A sheet-like optical article intended to obtain directional luminance is used. In the sheet-like optical article, the required characteristics as described above are becoming more severe as the screen size of the transmission type liquid crystal display element is increased. As methods for producing these optical elements, various methods using an energy ray curable resin composition have been proposed.

  Such an optical element usually has excellent shape retention characteristics such as shape retention force and restoring force of the optical resin layer, and has excellent durability because it needs to withstand long-term use. It is requested. In addition, when the molded product is in the form of a sheet, warping and optical distortion are often generated, and it is also required not to cause deformation such as bending and depression due to pressing. In particular, an optical article in which a warp of a sheet-like optical article due to a large screen of a liquid crystal display element, that is, a so-called curl phenomenon, is likely to cause a problem in an assembly process of the liquid crystal display element.

  Many methods have been proposed to improve the various problems as described above. Among these proposals, attention was paid to the structure of the resin material in the energy ray curable resin composition to be used and the number of functional groups thereof. As a proposal, a method using a resin composition of a specific high molecular weight energy ray curable oligomer, for example, a polyester oligomer obtained by reacting a polybasic acid and a polyhydric alcohol has a diisocyanate and a hydroxyl group in the molecule (meta ) An active energy ray-curable resin composition containing a 2- to 4-functional urethane-modified polyester (meth) acrylate oligomer obtained by reacting an acrylate, a trifunctional (meth) acrylate, and a monofunctional (meth) acrylate Do not provide a cured resin layer cured with active energy rays such as ultraviolet rays on a substrate such as glass. There is an optical element (for example, see Patent Document 1.). Also contains 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 A method using an optical active energy ray-curable resin composition is disclosed (for example, see Patent Document 2).

  However, when an optical article is actually manufactured, the above-described curl resistance and shape retention force cannot be satisfied even with these optical article manufacturing methods according to the prior art.

  In response to these problems, a method using an energy beam curable resin composition in which the cured product has no yield point in the relationship diagram between the tensile stress and strain of the cured product is disclosed, and the shape retention of the cured product is insufficient. Improvements have been made in terms of plastic deformation and curl resistance, referred to as “placement marks” (see, for example, Patent Document 3). However, in the described resin material, there is no way of controlling the crosslink density of the cured product focusing on the number of functional groups of (meth) acrylate and the distance between the functional groups. The required characteristics for the more severe shape retention characteristics in the large-sized sheet-like optical article could not be satisfied.

JP-A-62-258401 JP-A-4-31414 Japanese Patent Laid-Open No. 9-61601

  The problems to be solved by the present invention are excellent in curling resistance and shape retention characteristics required for the above-mentioned sheet-like optical articles, and have good physical properties such as transparency and surface hardness, and are produced with a short curing time. It is in providing the active energy ray hardening-type resin composition for optical articles which can improve property.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors cured using urethane (meth) acrylate having 3 acryloyl groups and (meth) acrylate having 3 acryloyl groups in the molecule. Active energy rays for optical articles disclosed in conventional Patent Documents 1 to 3 by controlling the crosslinking density of the product and using the active energy ray-curable resin composition in which the cured product has no yield point The present inventors have completed the present invention by finding out that the curl resistance and shape retention characteristics, which have been difficult with a curable resin composition, are satisfied, and that they are excellent in transparency, surface hardness and the like.

That is, the present invention starts photopolymerization with urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule and (meth) acrylate (B) having three (meth) acryloyl groups in the molecule. An active energy ray-curable resin composition for optical articles comprising an agent, wherein the urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule has three isocyanate groups. The cured product obtained by reacting the compound having the compound represented by the general formula (1) with the ultraviolet ray of 500 mJ / cm ² of the composition is cured with tensile stress and strain. The active energy ray-curable resin composition for optical articles is characterized by having no yield point in the relationship diagram of FIG.

〔式中、Ｒ１は水素原子またはメチル基を示し、Ｒ２、Ｒ３は置換基を有していても良く分岐していても良い炭素原子数２〜８のアルキレン鎖を示し、ｍは１以上の整数であり、ｎは０以上の整数であり、かつ、ｍとｎとの和（ｍ＋ｎ）が３又は４である。〕

[Wherein R1 represents a hydrogen atom or a methyl group, R2 and R3 each represents an alkylene chain having 2 to 8 carbon atoms which may have a substituent or may be branched ; It is an integer, n is an integer of 0 or more, and the sum (m + n) of m and n is 3 or 4. ]

  The present invention satisfies the curl resistance and shape retention characteristics required for a sheet-like optical article, is excellent in transparency, surface hardness, etc., has a short curing time, and is excellent in productivity. A curable resin composition can be provided.

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

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

  A sheet-like optical article may be locally deformed by an external force during the manufacturing process or when it is incorporated into an apparatus. For example, when a sheet-like optical article is wound up with a foreign object or air bubble in between, a large stress is locally applied to the location where the foreign object exists. In some cases, a sheet take-up roll or a plurality of sheet-like optical articles are stacked and stored. In these cases, stress is concentrated locally by its own weight. In this case, the local deformation remains as distortion, and the deformation may still remain even after the stress is released. This is considered to be because plastic deformation occurs in the optical article due to excessive stress.

  In particular, this plastic deformation cannot be completely eliminated simply by controlling the elastic modulus, and the occurrence of plastic deformation is related to the presence or absence of the yield point of the tensile stress-strain curve, and has no yield point. The cured product using the active energy ray-curable resin composition for optical articles according to the above is free from the occurrence of plastic deformation and is good.

1 to 3 schematically show the relationship between tensile stress (Pa) and strain (%) measured at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 2% according to the measurement method of JIS K7113. It is. Strain (%) is the difference between the length (l) of the sample after tension and the length (l ₀ ) of the initial sample divided by the length (l ₀ ) of the initial sample, and the percentage is shown as a percentage. The strain (%) = [(l−l ₀ ) / l ₀ ] × 100.

  In the present invention, the cured product having no yield point means that the relationship between tensile stress (Pa) and strain (%), that is, the tensile stress-strain curve of the cured product, or generally SS (stress- In a relational diagram called a (strain) curve or SS characteristic, for example, there is no yield point as shown in FIG. Further, as shown in FIG. 3, even when there is no yield point, the stress at break (σ2) is the intersection of the tangent at the initial tensile deformation point and the stress at the strain at break (σ1) on the tensile stress-strain curve. ) Ratio, that is, (σ2 / σ1) is particularly preferably one showing a value of 0.5 or more in order to shorten the time required for deformation recovery of the cured product after removing the external force.

  Next, the active energy ray-curable resin composition for an optical article of the present invention for the problems as described above is merely that the cured product of the composition does not have a yield point in the relationship diagram between tensile stress and strain. It is difficult to solve.

  Urethane capable of forming hydrogen bonds and exhibiting excellent cured properties as a means to improve the characteristics to the stricter shape retention required for large-sized sheet-like optical articles accompanying the increase in screen size of transmissive liquid crystal display elements It is essential to precisely control the number of functional groups of (meth) acrylate and (meth) acrylate used at the same time and the distance between the functional groups to control the crosslinking density and physical properties of the cured product. That is, an active energy ray-curable resin for optical articles comprising urethane (meth) acrylate having three (meth) acryloyl groups in the molecule and (meth) acrylate having three (meth) acryloyl groups in the molecule. It is essential that it is a composition.

  The resin composition of the present invention is substantially free of monofunctional or bifunctional reactive diluent as a constituent of the composition, and is composed of two different specific compounds having three polymerization functional groups. It is possible to precisely control the distance between cross-linking points and the cohesion between molecules due to hydrogen bonding. Therefore, it is possible to impart high shape retention characteristics while suppressing the curling phenomenon of the cured product.

  Specifically, hydrogen bonds are formed by urethane bonds contained in the compound having three acryloyl groups used in the present invention, and intermolecular cohesion is increased by the hydrogen bonds formed between the molecules, thereby increasing the curing rate. Increases, and the physical property strength is further increased.

  The urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule used in the present invention reacts with a compound having three isocyanate groups and a compound represented by the general formula (1). The compound obtained by making it contain is mentioned.

〔式中、Ｒ１は水素原子またはメチル基を示し、Ｒ２、Ｒ３は置換基を有していても良く分岐していても良い炭素原子数２〜８のアルキレン鎖を示し、ｍは１以上の整数であり、ｎは０以上の整数であり、かつ、ｍとｎとの和（ｍ＋ｎ）が３又は４である。〕

[Wherein R1 represents a hydrogen atom or a methyl group, R2 and R3 each represents an alkylene chain having 2 to 8 carbon atoms which may have a substituent or may be branched ; It is an integer, n is an integer of 0 or more, and the sum (m + n) of m and n is 3 or 4. ]

  As typical examples of trifunctional isocyanate compounds, for example, triphenylmethane triisocyanate, tris (isocyanatophenyl) as described in "Polyurethane resin handbook (edited by Keiji Iwata, Nikkan Kogyo Shimbun)" ) Thiophosphate, lysine ester triisocyanate, 2-isocyanate ethyl-2,6-diisocyanate caproate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,3,6 -Hexamethylene triisocyanate, bicycloheptane triisocyanate and the like, and tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hydrogenated 4,4'-diphenyl described in the above references Tan 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, tetremethylxylene diisocyanate And compounds obtained by trimerizing aromatic, aliphatic, and alicyclic diisocyanate compounds such as trimethylhexamethylene diisocyanate, such as burette polyisocyanate of diisocyanate and isocyanurate type polyisocyanate of diisocyanate. Moreover, the compound whose average functional group number of the isocyanate group is 3 among the polyisocyanate compounds which have the phenyl isocyanate frame | skeleton called the high molecular weight MDI which consists of a polynuclear mixture of several types of structures can also be used.

  Examples of the compound represented by the general formula (1) or (2) include (meth) acrylate compounds having a hydroxyl group in the molecule. Specifically, representative examples include 2-bidoxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, 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 a block structure oxyalkylene chain 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 above general formula (1) or (2), in order to control the distance between functional groups in the urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule of the present invention. The length of the hydroxyl group and (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 curling phenomenon due to an increase in the crosslink density, and reduces the hardness due to the extreme decrease in the crosslink density or balance of various characteristics due to the appearance of the yield point. 3 or 4 is preferable in order to suppress the deterioration.

  In the present invention, a urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule is reacted with a compound having three isocyanate groups and a (meth) acrylate compound having a hydroxyl group in the molecule. When obtained, 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 1.0 to 1. .2 in the range of 60 to 100 ° C. In this case, various urethanization catalysts may be used.

  As the (meth) acrylate (B) having three (meth) acryloyl groups in the molecule used in the present invention, a monomer having a structure in which three (meth) acrylic acids are bonded to a compound containing a hydroxyl group by an esterification reaction. Preferred and particularly representative examples are 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 (hydroxypropyl) isocyanurate added with 1 to 20 mol of ethylene oxide tri ( ) Acrylate compound: Trimethylolpropane, glycerin, pentaerythritol, trimethylolethane, tris (2-hydroxyethyl) isocyanurate, tris (hydroxypropyl) isocyanurate added with 1 to 20 mol of propylene oxide 1 to 20 mol of ε-caprolactone was added to trimethylolpropane, glycerin, pentaerythritol, trimethylolethane, tris (2-hydroxyethyl) isocyanurate, tris (hydroxypropyl) isocyanurate Examples thereof include tri (meth) acrylate compounds of hydroxyl group-containing compounds.

  The urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule used in the present invention described above is a urethane (meth) acrylate that forms a hydrogen bond and exhibits excellent cured properties. In order to form a cured resin layer having toughness and environmental resistance characteristics on the cured resin layer obtained, the active energy ray-curable resin composition for optical articles of the present invention is usually 10 to 90% by weight, Preferably it can contain 20-80 weight%.

  The (meth) acrylate (B) having three (meth) acryloyl groups in the molecule used in the present invention is the number of functional groups of (meth) acrylate and the distance between the functional groups in the same manner as the component (A) described above. The active energy ray-curable resin composition for optical articles of the present invention is used for controlling the viscosity of the active energy ray-curable resin composition for optical articles of the present invention to an appropriate value. The product can usually contain 10 to 90% by weight, preferably 20 to 80% by weight.

  In the present invention, active energy rays are 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 beams 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, they are dissociated by ultraviolet light or visible light having a wavelength of 1,000 to 8,000 angstroms to generate radicals. Such a photoinitiator should be used.

  As such a photopolymerization initiator, a photopolymerization initiator that can be dissociated by light to generate radicals can be used, and such a photopolymerization initiator can be used. Examples of typical photopolymerization initiators used in the present invention include benzophenone, 3,3-dimethyl-4-methoxybenzophenone, 4,4′-bisdimethylaminobenzophenone, and 4,4′-bisdiethylaminobenzophenone. Benzophenones such as 4,4-dichlorobenzophenone, Michler's ketone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone; xanthone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2 -Xanthone such as chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, thioxanthone-4-sulfonic acid; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin Acylloin ethers such as propyl ether, benzoin-n-butyl ether, benzoin isobutyl ether and benzoin butyl ether; 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, butyl 4-dimethylaminobenzoate, 2-dimethylhexyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid And benzoic acids such as 2-isoamyl.

  In addition, 3,3′-carbonyl-bis (7-diethylamino) coumarin, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-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-methylpropan-1-one, 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 -Ethoxycarbonyl) oxime, 1-phenyl-3-ethoxy-propanetrione-2- (o-benzoyl) oxime, methyl o-benzoylbenzoate, bis (4-dimethylaminophenyl) ketone, p-dimethylaminoacetophenone, α, α-dichloro-4-phenoxyacetophenone, pentyl- -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-triazine anthraquinone, 2 -T-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone and the like.

  Moreover, a commercial item can also be used as a photo (polymerization) initiator. For example, Irgacure-184, 149, 261, 369, 500, 651, 784, 819, 907, 1116, 1664, 1700, 1800, 1850, 2959, 4043 , Darocur-1173 (manufactured by Ciba Specialty Chemicals), Lucyrin TPO (manufactured by BASF), KAYACURE-DETX, MBP, DMBI, EPA, OA (manufactured by Nippon Kayaku), VICURE-10, 55 (STAUFFER Co.LTD), TRIGONALP1 (AKZO Co.LTD), SANDORY 1000 (SANDOZ Co.LTD), DEAP (APJOHN Co.LTD), QUANTACURE-PDO, ITX, EPD (WARD BLEKINSOP Co. LTD)).

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

  These may be used alone or in combination of two or more. The amount used is not particularly limited, but is 0.01 to 20 with respect to the photopolymerizable monomer in the composition in order to keep the sensitivity good, suppress the precipitation of crystals, and keep the coating film properties good. It can be used so that it is contained by weight%, more preferably 0.1 to 10% by weight.

  Among these, 1-hydroxycyclohexyl phenyl 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-diphenylethane-1-one, 2,4,6-trimethylbenzoyldiphenoylphosphine oxide, 2-methyl- 1 type selected from the group of 1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one or Two or more types of mixed systems are particularly preferable because of high curability.

  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 the transparent substrate surface serving as a support. In that case, the photoinitiator that can be used is preferably an initiator having a light absorbing ability in a long wavelength region, and it is desirable to use a photoinitiator having a photoinitiating ability in the range of 360 nm to 450 nm. Those that absorb light of 450 nm or more have poor stability of the composition, and need to be manufactured in a completely light-shielded environment, which makes it extremely difficult to handle.

  In addition, when using an electron beam, these photoinitiators and photosensitizers are unnecessary.

  The active energy ray means an electromagnetic wave or charged particle beam having an energy quantum capable of polymerizing and cross-linking molecules. Usually, ultraviolet rays, electron beams, etc. are used. In the case of ultraviolet rays, an ultrahigh pressure mercury lamp is used. A light source such as a high-pressure mercury lamp, a low-pressure mercury lamp, a carbon arc, a black light lamp, or a metal halide lamp can be used. As the ultraviolet wavelength, a wavelength range of 1900 to 3800 angstroms is mainly used.

  In the case of an electron beam, it is equipped with an irradiation source such as a cockroft Walton type, a bandegraph type, a resonant transformer type insulated core transformer type, or various electron beam accelerators such as a linear type, a dynamitron type, and a high frequency type. An apparatus can be used, and electrons having an energy of 100 to 1000 KeV, preferably 100 to 300 KeV are irradiated. As an irradiation dose, about 0.5-30 Mrad is preferable normally.

  Naturally, the active energy ray-curable resin composition for optical articles of the present invention is excellent in transparency. In a cured product having a thickness of 0.3 mm, the light transmittance in the wavelength region of 400 to 900 nm is at least 80% or more, preferably 85% or more, and more preferably 90% or more.

  If necessary, in the resin composition, various additives such as ultraviolet absorbers, light stabilizers, antioxidants can be used to improve the coating film, improve paintability, and release from the matrix. It is also possible to add a rheology control agent, a silicon additive, a defoaming agent, a release agent, an antistatic agent and the like.

  The active energy ray-curable resin composition for an optical article of the present invention is used for a transmissive display backlight (back light source) such as a transmissive liquid crystal display element, a video projector, an advertising board, a light diffusing plate, and a back reflection lens. Used as an optical article having a prism action or lens action, such as a lens array sheet, or a planar optical article such as a lenticular lens or a Fresnel lens constituting a projection television screen, a pickup lens for reading an optical disc signal A structure in which a fine optical molding layer such as a lens pattern made of a cured resin is provided on a transparent substrate such as a camera lens for a video camera, a still camera, etc., an optical element for irregular reflection prevention on the surface of a CRT or a liquid crystal display element, etc. Material suitable for various optical articles used for optical elements, etc., suitable for sheet-like optical articles Used. Also, depending on the use, even if a transparent substrate having another shape such as a film shape or a plate shape is used, it can be used for various optical articles used in an optical element having a structure provided with a fine optical molding layer. it can.

  These optical articles are prepared, for example, by applying the active energy ray-curable resin composition for optical articles of the present invention onto a matrix having a required fine shape, and the active energy ray-curable resin composition for optical articles. After forming a physical layer, a transparent substrate serving as a support is bonded on the layer, and then the resin composition is cured by irradiating an active energy ray from the transparent substrate surface in this state, and then the matrix It is manufactured by peeling from.

  Examples of the sheet-like, film-like, and plate-like transparent base materials that can be used for this include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), triacetyl cellulose, polycarbonate resin, and methyl methacrylate. Examples thereof include acrylic resins such as copolymers, styrene resins, polysulfone resins, polyethersulfone resins, polycarbonate resins, vinyl chloride resins, polymethacrylimide resins, and glass.

  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)
In a flask equipped with a thermometer, a stirrer, and a condenser, 660 parts of a ring-opening reaction product of ε-caprolactone and hydroxyethyl acrylate (OH value = 163 KOH-mg / Kg, m + n = 3 in the general formula (1)) The mixture was heated to 60 ° C. with stirring, and 340 parts of a hexamethylene diisocyanate burette type polyisocyanate (NCO% = 23.3%) was added and reacted for 1 hour while paying attention to heat generation. The reaction was carried out for 10 hours, and it was confirmed by the infrared absorption spectrum that the absorption of the isocyanate group had disappeared. Thus, the intended urethane acrylate (A-1) having three acryloyl groups was obtained.

(Synthesis Example 2)
In a flask equipped with a thermometer, a stirrer, and a condenser, 727 parts of a ring-opening reaction product of ε-caprolactone and hydroxyethyl acrylate (OH value = 123 KOH-mg / Kg, m + n = 4 in the general formula (1)) The mixture was heated to 60 ° C. with stirring, and 273 parts of hexamethylene diisocyanate isocyanurate type polyisocyanate (NCO% = 23.8%) 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 by the infrared absorption spectrum that the absorption of the isocyanate group had disappeared. Thus, the intended urethane acrylate (A-2) having three acryloyl groups 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, heated to 60 ° C. with stirring, and a polyester diol of 1,6-hexanediol and adipic acid (OH value = 51 KOH). -mg / Kg) 2200 parts were 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 further carried out for 10 hours. It was confirmed by the infrared absorption spectrum that the absorption of the isocyanate group had disappeared, and urethane acrylate (HA-1) having two target acryloyl groups was obtained.

(Examples 1-4)
The active energy ray-curable resin composition for optical articles was prepared according to the formulation shown in Table 1. Next, the obtained active energy ray-curable resin composition for optical articles is composed of a mold having a repetitive chevron shape with 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. In between, it was cured by irradiating with an ultraviolet ray of 800 mJ / cm 2 with an ultra high pressure mercury lamp. After UV curing, the transparent PET film was peeled off from the mold together with the active energy ray curable resin layer, and an optical article having the required shape transferred was produced.

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

  Further, the obtained active energy ray-curable resin composition for optical articles was applied on a transparent PET film to a thickness of about 20 μm, cured by irradiating with an ultrahigh pressure mercury lamp with 500 mJ / cm 2 of ultraviolet rays, It was set as the sample of the sex test.

Evaluation was performed using these optical articles according to the following measurement and test methods. The evaluation results are shown in Table 2.
(1) Curability: When irradiated with a 160 W / cm high-pressure mercury lamp at a lamp height of 15 cm and a line speed of 10 m / min, the number of irradiation until the surface tack free was measured. When the number of times of irradiation is smaller, the curability is better. When the number of times of irradiation is less than 2 passes, tackiness is not good.

(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 is measured. However, less than that was marked with x.

(3) Plate separation property: When creating an optical article with a shape created using a transparent PET film, it can be created without a large load at the time of peeling, and the article is bent by a large peeling sound or load at the time of peeling. And those that could cause peeling marks were marked with x.

(4) Initial appearance determination: The appearance after creation of the shaped optical article was visually determined. Judgment criteria are: ○ when a uniform lens surface shape was obtained, △ when a crack or partial omission was seen, and x when a crack or omission of the shape was observed over the entire surface. did.

(5, 6) Yield point determination and elasticity evaluation: The test piece having a thickness of 300 μm was punched out using a dumbbell super dumbbell (JIS 7113 No. 2 dumbbell) to make a measurement sheet, and the tensile modulus was measured. It was. However, at the time of measurement, for the purpose of preventing the measurement sheet from slipping on the chuck, the left and right and top and bottom four places outside the marked line (25 mm) are a steel plate and adhesive (Toa Gosei Chemical Co., Ltd.) with a thickness of 0.3 mm and a length and width of 20 mm It was fixed using Aron Alpha) and used as a grip part. The tester was Tensilon manufactured by Toyo Baldwin, and the deformation rate was 1.0 mm / min. Measurement was performed in an atmosphere of 25 ° C. and 50% relative humidity.

Yield point determination is expressed as A with a pattern having no yield point as shown in FIGS. 1 and 3 as B and B with a yield point as shown in FIG. Described in. The tensile elastic modulus was calculated from the slope of the SS curve (stress-strain curve) drawn from the tensile deformation start point (the number of measurements was 5 times and the average value was used). In the evaluation of elasticity (σ2 / σ1), σ2 / σ1 was calculated by reading σ2 and σ1 from the SS curve having the pattern as shown in FIG. (7) Curling resistance: A test cured 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 strip-shaped test piece of 70 mm × 20 mm was obtained. The end 5 mm of the 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 marked with ◯, and the case where the distance was more than 0.5 mm.
(8) Shape-retaining characteristics: active energy ray-curable resin layer on top of a sheet-like optical article with a shape produced using a transparent PET film on a smooth metal plate at a temperature of 25 ° C. Then, a cylindrical indenter (diameter 2 mm) with a flat contact surface was placed thereon, and a 1 kg load was applied for 20 minutes. Subsequently, the load was removed, and the presence or absence of deformation traces was visually determined for each sheet-shaped optical article with a fluorescent lamp as a watermark or reflected light. Judgment criteria for shape retention force are those in which the traces of deformation of the sheet cannot be confirmed within 2 minutes ◎ those in which the traces of deformation of the sheet cannot be confirmed within 5 minutes ○ The thing which can confirm a deformation | transformation trace was set as x.

(Comparative Examples 1-3)
A comparative active energy ray-curable resin composition was prepared according to the formulation shown in Table 1. About this, the optical article for evaluation and the hardened | cured material for a test were produced similarly to Examples 1-5. Table 2 shows the results of comparative evaluation as in the examples.

ＰＯ３−ＴＭＰＴＡ：トリメチロールプロパンにプロピレンオキサイドを３モル付加させた水酸基含有化合物のトリアクリレート化合物
ＥＯ１５−ＴＭＰＴＡ：トリメチロールプロパンにエチレンオキサイドを１５モル付加させた水酸基含有化合物のトリアクリレート化合物
ＴＭＰＴＡ：トリメチロールプロパンのトリアクリレート化合物
ＮＰＧＤＡ：ネオペンチルグリコールのジアクリレート化合物
ＤＰＨＡ：ジペンタエリスリトールのヘキサアクリレート化合物
ＴＰＧＤＡ：トリプロピレングリコールのジアクリレート化合物

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

It is a schematic diagram which shows the relationship (SS curve) of tensile stress (Pa) and distortion (%). The vertical axis represents tensile stress (Pa) and the horizontal axis represents strain (%). (This is a pattern with no yield point.) It is a schematic diagram which shows the relationship (SS curve) of tensile stress (Pa) and distortion (%). The vertical axis represents tensile stress (Pa) and the horizontal axis represents strain (%). (This is a pattern where the yield point can be seen.) It is a schematic diagram which shows the relationship (SS curve) of tensile stress (Pa) and distortion (%). The vertical axis represents tensile stress (Pa) and the horizontal axis represents strain (%). (This is a pattern with no yield point.)

Claims (4)

A urethane (meth) acrylate (A) having three (meth) acryloyl groups in the molecule, a (meth) acrylate (B) having three (meth) acryloyl groups in the molecule, and a photopolymerization initiator. An active energy ray-curable resin composition for optical articles, wherein a urethane (meth) acrylate (A) having three (meth) acryloyl groups in a molecule is a compound having three isocyanate groups and a general formula ( 1) obtained by reacting with the compound represented by 1), and a cured product obtained by irradiating the composition with ultraviolet rays of 500 mJ / cm ² yields a yield point in a relationship diagram between tensile stress and strain. An active energy ray-curable resin composition for optical articles, characterized by not having any of the above.

[Wherein R1 represents a hydrogen atom or a methyl group, R2 and R3 each represents an alkylene chain having 2 to 8 carbon atoms which may have a substituent or may be branched ; It is an integer, n is an integer of 0 or more, and the sum (m + n) of m and n is 3 or 4. ] 2. The (meth) acrylate (B) having three (meth) acryloyl groups in the molecule has a structure in which three (meth) acrylic acids are bonded to a compound containing a hydroxyl group by an esterification reaction. An active energy ray-curable resin composition for optical articles. (Meth) acrylate (B) having three (meth) acryloyl groups in the molecule is a tri (meth) acrylate compound of trimethylolpropane, and a hydroxyl group-containing compound in which 1 to 20 mol of ethylene oxide is added to trimethylolpropane 3. One or more compounds selected from the group consisting of a tri (meth) acrylate compound of a hydroxyl group-containing compound obtained by adding 1 to 20 mol of propylene oxide to trimethylolpropane and a tri (meth) acrylate compound. The active energy ray-curable resin composition for optical articles described. A (meth) acrylate (B) having three (meth) acryloyl groups in the molecule is a tri (meth) acrylate compound of trimethylolpropane , and a triacrylate of a hydroxyl group-containing compound obtained by adding 15 moles of ethylene oxide to trimethylolpropane. 4. The active energy ray-curable resin for optical articles according to claim 3 , wherein the compound is one or more compounds selected from the group consisting of a triacrylate compound of a hydroxyl group-containing compound obtained by adding 3 moles of propylene oxide to trimethylolpropane. Composition.

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