JP2011213819A - Ultraviolet curable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-refractive-index ultraviolet curable resin composition that does not generate unpleasant odors, exhibits reduced yellowing after long-term use on a liquid crystal display screen and is excellent in transparency while having a high refractive index.SOLUTION: The ultraviolet curable resin composition (Q) includes (A) a (meth)acrylic compound represented by formula (1) and (B) a photoinitiator as essential components [in the formula, R, Rand Rare each independently a hydrogen atom or a methyl group; the average value of n is a number of 0 to 10; and the average value of m is a number of 2.1 to 5.0].

Description

  The present invention relates to an ultraviolet curable resin composition. More specifically, the present invention relates to an ultraviolet curable resin composition suitable for a transmissive screen such as a prism lens sheet, a diffusion lens sheet, and a lenticular lens used in a liquid crystal television, a projection television, and the like, and a cured product thereof.

In recent large-sized liquid crystal televisions, direct type backlights in which a plurality of cold-cathode tubes and LEDs are arranged as light sources are employed. A diffusion lens sheet is used as a resin plate having a strong light scattering property on the light source, so that a cold cathode tube or an LED as a light source is not visually recognized. Furthermore, in order to improve the brightness of the liquid crystal display screen by directing the light scattered by the diffusing lens sheet in one direction, unit prisms having a triangular cross section are periodically arranged in one direction on the base film. A prism lens sheet is used.
In order to improve the brightness of the liquid crystal display screen by using the prism lens sheet, measures for increasing the refractive index of the resin in the prism portion and measures for optimizing the shape of the unit prism are known.

As a general method for manufacturing a prism lens sheet, for example, an ultraviolet curing method using an ultraviolet curable resin composition is used from the viewpoint of productivity and manufacturing cost.
As a method of manufacturing a prism lens sheet using an ultraviolet curing method, after applying an ultraviolet curable resin composition to a mold having a prism shape, the substrate film is pressed and irradiated with ultraviolet rays from the substrate film side. A method is used in which the ultraviolet curable resin composition is cured, and then the base film and the cured ultraviolet curable resin composition are released from the mold.

In order to increase the refractive index of the resin composition in order to improve the brightness of the liquid crystal display screen using the prism lens sheet, a method using a monomer containing a sulfur atom in the molecule (Patent Document 1), naphthalene, biphenyl, etc. A method using a monomer having an aromatic polycyclic structure (Patent Document 2), a method of adding inorganic fine particles such as titanium oxide for increasing the refractive index (Patent Document 3), and the like have been proposed.
However, the method using a monomer containing a sulfur atom has a problem of light resistance that increases yellowing when used for a long time on a liquid crystal display screen, and an unpleasant odor problem peculiar to sulfur compounds.
In addition, in the method using a monomer having an aromatic polycyclic structure, the absorption wavelength region of ultraviolet rays is wider than that of a general material. Therefore, when used for a long time on a liquid crystal display screen, the light resistance is extremely large. There's a problem. In addition, the method of adding inorganic fine particles has a problem that the haze of the prism lens sheet is increased, so that the transparency is poor and the luminance of the liquid crystal display screen is not improved.

Japanese Patent Laid-Open No. 11-311702 JP-A-5-65318 JP 2008-158513 A

  Therefore, the present invention provides a high refractive index ultraviolet curable resin composition that does not generate an unpleasant odor, has a high refractive index, has little yellowing when used on a liquid crystal display screen for a long period of time, and has excellent transparency. The purpose is to provide goods.

The inventors of the present invention have reached the present invention as a result of studies to achieve the above object.
That is, this invention contains the (meth) acrylic compound (A) represented by following General formula (1), and a photoinitiator (B) as an essential component, The ultraviolet curable resin composition characterized by the above-mentioned. (Q).

[In formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom or a methyl group, the average value of n is 0 to 10 and the average value of m is 2.1 to 5.0. Is the number of ]

Since the ultraviolet curable resin composition (Q) of the present invention contains the (meth) acrylic compound (A), it has a high refractive index and excellent transparency. Furthermore, since it contains a photopolymerization initiator (B), it can be cured by ultraviolet rays. Further, since the ultraviolet curable resin composition (Q) does not contain a sulfur atom and an aromatic polycyclic structure, it does not emit an unpleasant odor and has good light resistance.
For this reason, when used as a prism lens sheet, it is a high refractive index ultraviolet curable resin composition, and does not generate an unpleasant odor during production, so it has excellent productivity, transparency, and light resistance. Can be used for a long time with LCD screen.
Furthermore, by using together the urethane oligomer (C) having a molecular weight of 1,000 to 10,000, it is possible to adjust the resin viscosity of the ultraviolet curable resin composition (Q), and the viscosity is adjusted to be suitable for the coating apparatus. It becomes easy. Moreover, resin strength can also be adjusted as needed by using together the polyfunctional (meth) acrylic compound (D) containing an acrylic group more than bifunctional.

The present invention is an ultraviolet curable resin composition (Q) comprising a (meth) acrylic compound (A) having a specific chemical structure and a photopolymerization initiator (B) as essential components.
The (meth) acrylic compound (A) of the present invention is represented by the following general formula (1).

[In formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom or a methyl group, the average value of n is 0 to 10 and the average value of m is 2.1 to 5.0. Is the number of ]
[In the formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom or a methyl group, n is a number having an average value of 0 to 10, and m is an integer having an average value of 1 to 5. ]

R ^{1 in} the general formula (1) of the (meth) acrylic compound (A) of the present invention is a hydrogen atom or a methyl group, and a hydrogen atom is preferable from the viewpoint of photopolymerization reactivity.
R ² is a hydrogen atom or a methyl group, and a hydrogen atom is preferable from the viewpoint of the refractive index after photocuring.
R ³ is a hydrogen atom or a methyl group, and is preferably a hydrogen atom from the viewpoint of ease of synthesis.

The average value of n in the general formula (1) of the (meth) acrylic compound (A) of the present invention is usually a number of 0 to 10.0, and preferably 0 from the viewpoint of the refractive index after photocuring. 0.1 to 8.0, more preferably 0.3 to 6.0, and particularly preferably 0.5 to 4.0.

Moreover, the average value of m in the general formula (1) is usually a number of 2.1 to 5.0, and preferably 2.2 to 5.0 from the viewpoint of the refractive index after photocuring and the ease of production. 4.5, more preferably 2.3 to 4.0.

The method for synthesizing the (meth) acrylic compound (A) of the present invention is not particularly limited. For example, ethylene oxide (hereinafter referred to as styrenated phenol compound (I) obtained by reacting phenol with styrene or α-methylstyrene). And AEO addition reaction product (II) to which propylene oxide (hereinafter abbreviated as PO) is added and (meth) acrylic acid for a synthesis method.
In the present invention, “(meth) acrylic compound” means “acrylic compound” and “methacrylic compound”.

The styrenation of phenol is disclosed in JP-A-58-115185 and JP-A-2-11533.
In the reaction of phenol and styrene, usually, 2.1 to 5 mol, preferably 2.2 to 4.5 mol, more preferably 2.3 to 4.0 mol of styrene is reacted with 1 mol of phenol. .

The addition reaction between the styrenated phenol compound (I) and ethylene oxide or propylene oxide is disclosed in Japanese Patent Publication Nos. 48-32000 and 2010-37426.
The alkylene oxide (hereinafter abbreviated as AO) addition reaction with ethylene oxide or propylene oxide is usually carried out in an amount of 0 to 10 moles, preferably 0 to 10 moles, preferably 1 mole of ethylene oxide or propylene oxide per mole of styrenated phenol compound (I). 0.1 to 8.0 mol, more preferably 0.3 to 6.0 mol, and particularly preferably 0.5 to 4.0 mol are added.

The esterification reaction between the AO addition reaction product (II) and (meth) acrylic acid is carried out in the presence of an esterification catalyst such as p-toluenesulfonic acid or sulfuric acid and a polymerization inhibitor such as hydroquinone or phenothiazine by a known method. And a reaction in a solvent (for example, toluene, benzene, cyclohexane, n-heptane, etc.) at a temperature of 70 to 150 ° C.
(Meth) acrylic acid is reacted in an amount of 1 to 5 mol, preferably 1.05 to 3 mol, per 1 mol of the AO addition reaction product (II). The esterification catalyst is present at a concentration of 0.1 to 15 mol% based on the (meth) acrylic acid used.

The content (% by weight) of the (meth) acrylic compound (A) in the ultraviolet curable resin composition (Q) of the present invention is usually 10 to 90%, preferably 15 to 80%, more preferably 20 to 70. %. If the content is 10% or more, the photocured product can exhibit a good refractive index, and if it is 90% or less, a good resin strength can be exhibited.

  In order to cause radical polymerization reaction of the double bond in the (meth) acrylic compound (A), the ultraviolet curable resin composition (Q) contains the photopolymerization initiator (B) as an essential component.

Examples of the photopolymerization initiator (B) include benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone, methyl benzoyl formate, isopropylthioxanthone, 4 , 4-bis (dimethylamino) benzophenone, 3,3-dimethyl-4-methoxy-benzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, tert-butylanthraquinone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin Propyl ether, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, -Isopropyl-2-hydroxy-2-methylpropiophenone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, 2-chlorothioxanthone, diethylthioxanthone, isopropylthioxanthone, diisopropylthioxanthone , Michler's ketone, benzyl-2,4,6- (trihalomethyl) triazine, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, 9-phenylacridine, 1,7-bis (9-acridinyl) heptane 1,5-bis (9-acridinyl) pentane, 1,3-bis (9-acridinyl) propane, dimethylbenzyl ketal, trimethylbenzoyldiphenylphosphine oxide, tribromomethylphenylsulfone and 2-benzyl-2 Dimethylamino-1- (4-morpholinophenyl) - butan-1-one, and the like.
A photoinitiator (B) may be used by 1 type, and may use 2 or more types together.

As the photopolymerization initiator (B), a commercially available product can be easily obtained. For example, as 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, Irgacure 907, Examples of 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one include Irgacure 369 (manufactured by Ciba Specialty Chemicals).

The content of the photopolymerization initiator (B) based on the weight of the solid content of the ultraviolet curable resin composition (Q) is preferably 0.001 to 10% by weight, more preferably 0.01 to 7% by weight, particularly Preferably it is 0.05-5 weight%.
If it is 0.001% by weight or more, the photocuring reactivity can be exhibited more satisfactorily, and if it is 10% by weight or less, the physical properties of the cured product can be exhibited more satisfactorily.

The ultraviolet curable resin composition (Q) preferably contains a urethane oligomer (C) for the purpose of adjusting the resin viscosity suitable for coating.
The number average molecular weight (hereinafter abbreviated as Mn) of the urethane oligomer (C) used in combination for this purpose is preferably from the viewpoint of flowability into the mold and prevention of dripping during coating. It is 1,000 to 10,000, more preferably 1,300 to 9,000, particularly preferably 1,500 to 8,000. When Mn is less than 1,000, there is a problem of dripping at the time of coating, and a problem that variation due to temperature is large, and there is a problem in flowability into the mold than 10,000.

Examples of the urethane oligomer (C) include (meth) acryl-containing urethane oligomer (C1), hydroxyl group-containing urethane oligomer (C2), and isocyanate group-containing urethane oligomer (C3).
Among these, from the viewpoint of easy handling and physical properties of the photocured product, (meth) acryl-containing urethane oligomer (C1) and hydroxyl group-containing urethane oligomer (C2) are preferable, and (meth) acryl-containing urethane oligomer (C1) is more preferable. ).

The (meth) acryl-containing urethane oligomer (C1) is synthesized by a reaction of an organic isocyanate (Ca), a polyol (Cb), and a hydroxyl group-containing (meth) acrylate (Cc).
The hydroxyl group-containing urethane oligomer (C2) and the terminal isocyanate group urethane oligomer (C3) are synthesized by a reaction of organic isocyanate (Ca) and polyol (Cb).

  The organic isocyanate (Ca) in the present invention includes an aromatic isocyanate (Ca-1) having 6 to 20 carbon atoms (excluding carbon in the NCO group, the same shall apply hereinafter), an aliphatic isocyanate having 2 to 18 carbon atoms (Ca -2), C4-C45 alicyclic isocyanate (Ca-3), C8-C15 araliphatic isocyanate (Ca-4), and (Ca-1) to (Ca-4) nurate Compound (Ca-5). Two or more of these may be combined.

  Examples of the aromatic isocyanate having 6 to 20 carbon atoms (Ca-1) include 1,3- and / or 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate (TDI). 4,4′- and / or 2,4′-diphenylmethane diisocyanate (MDI), m- and p-isocyanatophenylsulfonyl isocyanate, 4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4, 4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, and m- and p-isocyanatophenylsulfonyl isocyanate; Isocyanates (such as triisocyanates), eg crude TDI, crude DI (polymethylene polyphenylene polyisocyanates) and 4,4 ', 4 "- triphenylmethane triisocyanate and the like.

  Examples of the aliphatic isocyanate (Ca-2) having 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene. Diisocyanate, 2,2,4- and / or 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, 2,6-diisocyanatoethylcaproate, bis (2 -Isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate and trimethylhexamethylene diisocyanate (TMDI); Isocyanates such as triisocyanates such as 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,3,6-hexamethylene triisocyanate and lysine ester triisocyanate (with lysine) Phosgenates of reaction products of alkanolamines, such as 2-isocyanatoethyl-2,6-diisocyanatohexanoate, 2- and / or 3-isocyanatopropyl-2,6-diisocyanatohexanoate) Etc.

  Examples of the alicyclic isocyanate (Ca-3) having 4 to 45 carbon atoms include isophorone diisocyanate (IPDI), 2,4- and / or 2,6-methylcyclohexane diisocyanate (hydrogenated TDI), dicyclohexylmethane-4, 4′-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis (2-isocyanatoethyl) -4-cyclohexylene-1,2-dicarboxylate and 2,5- and / or 2, 6-norbornane diisocyanate, dimer acid diisocyanate (DDI); and tri- or higher functional isocyanates (such as triisocyanate), such as bicycloheptane triisocyanate.

  Examples of the araliphatic isocyanate having 8 to 15 carbon atoms (Ca-4) include m- and / or p-xylylene diisocyanate (XDI), diethylbenzene diisocyanate, and α, α, α ′, α′-tetramethylxylyl. Range isocyanate (TMXDI) etc. are mentioned.

Among these organic polyisocyanates (Ca), aromatic isocyanate (Ca-1) having 6 to 20 carbon atoms and araliphatic isocyanate (Ca-4) having 8 to 15 carbon atoms are preferable from the viewpoint of refractive index.

In the polyol (Cb) in the present invention, for example, an aliphatic dihydric alcohol (Cb-1) [(di) alkylene glycol (ethylene glycol) having 2 to 12 carbon atoms (hereinafter sometimes abbreviated as C). Diethylene glycol, propylene glycol, dipropylene glycol, 1,2-, 2,3-, 1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol and 3-methylpentanediol, dodecanediol Etc.), dihydric alcohols having an alicyclic skeleton having 6 to 10 carbon atoms (Cb-2) [1,3- and 1,4-cyclohexanediol, cyclohexanedimethanol and the like], 8 to 20 carbon atoms Aromatic aliphatic dihydric alcohol (Cb-3) [xylylene glycol, bis (hydroxyethyl) benzene, bis Phenol A, bisphenol F, bisphenol S, dihydroxynaphthalene, etc.], the (Cb-1) AO1~50 mole adduct of ~ (Cb-3) (Cb-4), and the like. Two or more of these may be combined.
Among these, from the viewpoint of refractive index, AO 1 to 50 mol adducts of araliphatic dihydric alcohols (Cb-3) and (Cb-3) having 8 to 20 carbon atoms are preferable.

Examples of the hydroxyl group-containing (meth) acrylate (Cc) include hydroxyalkyl (meth) acrylate [2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, etc.], Examples include polyalkylene glycol mono (meth) acrylate [polyethylene glycol mono (meth) acrylate and the like], alkylol (meth) acrylamide [N-methylol (meth) acrylamide and the like] and the like.

  The NCO / OH equivalent ratio in the reaction of the organic isocyanate (Ca) with the polyol (Cb) and the hydroxyl group-containing (meth) acrylate (Cc) is not particularly limited, but is preferably 1 / 0.5 to from the viewpoint of storage stability. 1/10, more preferably 1 / 0.7 to 1/5, particularly preferably 1/1 to 1/2.

  In the production of a urethane oligomer (C) obtained by reacting an organic isocyanate (Ca), a polyol (Cb), and a hydroxyl group-containing (meth) acrylate (Cc), a urethanization catalyst may be used. Urethane catalysts include metal compounds (organic bismuth compounds, organic tin compounds, organic titanium compounds, etc.) and quaternary ammonium salts.

  The amount of urethanization catalyst used is usually 1% or less based on the total weight of (Ca), (Cb), and (Cc), preferably 0.001 to 0.5% from the viewpoint of reactivity and transparency, More preferably, it is 0.05 to 0.2%.

  The conditions for the urethanization reaction of (Ca), (Cb), and (Cc) are not particularly limited, and are usually 40 to 100 ° C., preferably 60 to 95 ° C. from the viewpoint of reactivity and stability of the mixture. The urethane oligomer (C) can be produced by reacting for 2 to 20 hours. Further, if necessary, the reaction may be carried out by diluting with a solvent (ethyl acetate, methyl ethyl ketone, toluene, etc.). The amount of the solvent used is usually 5,000% or less based on the total weight of the urethane oligomer (C), the lower limit is preferably 10% from the viewpoint of the handleability of the mixture, and the upper limit is preferably 1,000 from the viewpoint of the reaction rate. %.

The benzene skeleton content (% by weight) in the urethane oligomer (C) is preferably 15 to 50%, more preferably 18 to 45%, particularly preferably 20 to 40% from the viewpoint of the refractive index and light resistance of the cured product. is there. Here, the benzene skeleton means only the carbon constituting the benzene ring or its condensed ring (eg, naphthalene ring). The benzene skeleton may be derived from organic polyisocyanate (Ca) or derived from polyol (Cb). The benzene skeleton content can be measured by ¹ H and ¹³ C-NMR (nuclear magnetic resonance spectrum) or IR (infrared absorption spectrum) analysis.
For example, ^{1 H-NMR,} in the case of obtaining the benzene skeleton content, adding an internal standard, and the integral value of the peak of the ^{1 H} from internal standard, ¹ on the benzene skeleton of the urethane oligomer (C) The number of moles of the benzene skeleton in the urethane oligomer (C) is determined from the ratio of the integral value of the H peak (around 7 to 8 ppm), and the benzene skeleton content can be determined by multiplying the molecular weight.

  The content (% by weight) of the urethane oligomer (C) in the ultraviolet curable resin composition (Q) of the present invention is usually 1 to 60%, preferably 2 to 55%, particularly preferably 3 to 50%. . If the content is 1% or more, dripping of the resin can be suppressed, and if it is 60% or less, the flowability into the mold is excellent.

The ultraviolet curable resin composition (Q) contains a polyfunctional (meth) acrylic compound (D) containing two or more (meth) acrylic groups in the molecule for the purpose of improving the physical properties of the photocured product. Is preferred.

  The polyfunctional (meth) acrylic compound (D) used in combination for this purpose contains two (meth) acrylic group-containing monomers (d-1), and three to six or more (meth) acrylic groups A monomer (d-2) is mentioned. Two or more of these may be combined.

Examples of the two (meth) acryl group-containing monomers (d-1) include aliphatic di (meth) acrylate [ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, etc.], fat Ring-containing di (meth) acrylate [dimethylolcyclotridecane diacrylate and the like] and di (meth) acrylate of bisphenol AO2 to 10 mol adduct [for example, EO2 mol of bisphenol A, PO4 mol of bisphenol A, -F and -S Each di (meth) acrylate etc. of an adduct] etc. are mentioned.
Among these, di (meth) acrylate of AO 2 to 10 mol adduct of bisphenol is preferable from the viewpoint of refractive index.

  Examples of the 3 to 6 or more (meth) acrylic group-containing monomer (d-2) include poly (meth) of polyvalent (trivalent to hexavalent or higher) alcohol (carbon number 3 to 40). Acrylates, such as trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane-PO3 molar adduct tri (meth) acrylate, trimethylolpropane-EO3 molar adduct tri (meth) acrylate, penta Erythritol tri (meth) acrylate, pentaerythritol-tetra (meth) acrylate, tetra (meth) acrylate of pentaerythritol-EO 4 mol adduct, dipentaerythritol-penta (meth) acrylate and dipentaerythritol-hexa (meth) acrylate And the like.

  The content (% by weight) of the polyfunctional (meth) acrylic compound (D) in the ultraviolet curable resin composition (Q) of the present invention is usually 0.5 to 80 from the viewpoint of the strength and curability of the cured product. %, Preferably 1 to 70%, particularly preferably 2 to 60%. If the content is 0.5% or more, the resin strength of the photocured product is excellent, and if it is 70% or less, the toughness after photocuring is excellent.

For the purpose of lowering the viscosity, the ultraviolet curable resin composition (Q) is one other than (A) having a styrenated phenol skeleton represented by the general formula (1), and having one or more (meta) ) A monofunctional (meth) acrylic compound (E) containing an acrylic group may be contained.

  Examples of the monofunctional (meth) acrylic compound (E) include aliphatic (meth) acrylate [methyl (meth) acrylate, ethyl (meth) acrylate, octyl acrylate, 2-ethylhexyl acrylate, etc.], alicyclic-containing (meth) acrylate. [Cyclohexyl (meth) acrylate, etc.], aromatic ring-containing (meth) acrylate [benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, etc.], heterocycle-containing compounds [tetrahydrofurfuryl (meth) acrylate, (meth) acryloylmorpholine Etc.] and [alkyl (1-20 carbons)] (meth) acrylate of phenol (6-30 carbons) AO 1-10 mol adduct [eg (meth) acrylate of phenol PO8 mol adduct, EO8 of nonylphenol Mole adduct (Meth) acrylate, etc.] and the like.

  The content (% by weight) of the monofunctional (meth) acrylic compound (E) in the ultraviolet curable resin composition (Q) of the present invention is usually 0.5 to 50%, preferably 1 to 45%, particularly preferably. Is 2-40%. If the content is 0.5% or more, the wettability to the mold is excellent, and if it is 50% or less, dripping can be suppressed.

The ultraviolet curable resin composition (Q) may further contain other components as necessary.
Examples of other components include a sensitizer (F1), a polymerization inhibitor (F2), a light stabilizer (F3), and a mold release agent (F4).

As the sensitizer (F1), nitro compounds (for example, anthraquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, benzanthrone, p, p'-tetramethyldiaminobenzophenone, carbonyl compounds such as chloranil, nitrobenzene, p -Dinitrobenzene and 2-nitrofluorene etc.), aromatic hydrocarbons (eg anthracene and chrysene etc.), sulfur compounds (eg diphenyl disulfide etc.) and nitrogen compounds (eg nitroaniline, 2-chloro-4-nitroaniline) , 5-nitro-2-aminotoluene, tetracyanoethylene and the like.

The content of the sensitizer (F2) based on the weight of the photopolymerization initiator (B) is usually 0.1 to 100% by weight, preferably 0.5 to 80% by weight, particularly preferably 1 to 70% by weight. is there.

There is no limitation in particular as a polymerization inhibitor (F2), What is used for normal reaction is used. Specifically, diphenylhydrazyl, tri-p-nitrophenylmethyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, p-benzoquinone, p-tert-butylcatechol, nitrobenzene, Examples include picric acid, dithiobenzoyl disulfide, and copper (II) chloride.

The content of the polymerization inhibitor (F2) based on the weight of the solid content of the ultraviolet curable resin composition (Q) is preferably 0 to 1.0% by weight, more preferably 0.01 to 0.5% by weight, Particularly preferred is 0.02 to 0.1% by weight.

Examples of the light stabilizer (F3) include an ultraviolet absorber and HALS. These may be used alone or as a mixture of two or more.

Examples of the ultraviolet absorber include benzotriazole compounds [2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3 , 5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, etc.], triazine compounds [2- ( 4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol], benzophenone (such as 2-hydroxy-4-n-octyloxybenzophenone), oxalic anilide And compounds (such as 2-ethoxy-2′-ethyloxalic acid bisanilide).

As HALS, for example, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- {2- (3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionyloxy) ethyl} -2,2,6,6-tetramethylpiperidine, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro {4.5} decane -2,4-dione, "Chemical products of 13700" (Chemical Industry Daily, 2000), p1069-1070, etc. are mentioned.

The content of the light stabilizer (F3) based on the weight of the solid content of the ultraviolet curable resin composition (Q) is preferably 0 to 5.0% by weight, more preferably 0.01 to 4.5% by weight, Particularly preferred is 0.02 to 4.0% by weight.

Examples of the mold release agent (F4) include phosphate ester activators (for example, phosphate esters disclosed in Patent Publication 2007-177161), fluorine activators, silicon activators, and the like.

The content of the mold release agent (F4) based on the weight of the solid content of the ultraviolet curable resin composition (Q) is preferably 0 to 1.0% by weight, more preferably 0.01 to 0.8% by weight. %, Particularly preferably 0.02 to 0.5% by weight.

The ultraviolet curable resin composition (Q) of the present invention is diluted with a solvent if necessary, applied to at least a part of at least one side of the substrate, dried if necessary, and then cured by irradiation with ultraviolet rays. Thus, a coating having a cured product on at least a part of the front surface and / or the back surface of the substrate can be obtained.
For coating, a commonly used apparatus such as a coating machine [bar coater, gravure coater, roll coater (size press roll coater, gate roll coater, etc.), air knife coater, spin coater, blade coater, etc.] can be used. The coating film thickness is usually 0.5 to 300 μm as the film thickness after curing and drying, and the preferable upper limit is 250 μm from the viewpoint of drying properties and curability, and the preferable lower limit is from the viewpoint of scratch resistance, solvent resistance, and contamination resistance. Is 1 μm.

When the ultraviolet curable resin composition (Q) of the present invention is used after being diluted with a solvent, it is preferably dried after coating.
Examples of the drying method include hot air drying (such as a dryer). The drying temperature is usually 10 to 200 ° C., the upper limit is preferably 150 ° C. from the viewpoint of the smoothness and appearance of the coating film, and the lower limit is preferably 30 ° C. from the viewpoint of the drying speed. The drying time is usually 10 minutes or less, and preferably 1 to 5 minutes from the viewpoint of physical properties and productivity of the cured film.

When the ultraviolet curable resin composition (Q) of the present invention is cured by ultraviolet irradiation, various ultraviolet irradiation apparatuses [for example, model number “VPS / I600”, manufactured by Fusion UV Systems Co., Ltd.], a xenon lamp as a light source, A high pressure mercury lamp, a metal halide lamp, etc. can be used. The dose of the ultraviolet radiation is typically 10~10,000mJ / cm ^2, preferably from a flexible viewpoint of curability and cured product of the composition (cured film) is 100~5,000mJ / cm ^2.

The refractive index at 23 ° C. of the photocured product of the ultraviolet curable resin composition (Q) of the present invention is usually 1.560 to 1.595, preferably 1.562 to 1.59 from the viewpoint of application to an optical member. 595.

As a method of increasing the refractive index, a method of increasing the proportion of the (meth) acrylic compound (A) in the ultraviolet curable resin composition (Q), m in the formula (1) of the (meth) acrylic compound (A) It can be increased by a method of increasing n and a method of decreasing n in the formula (1) of the (meth) acrylic compound (A).

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

<Synthesis Example 1>
<Synthesis Method of (Meth) acrylic Compound (A-1)>
In a flask equipped with a stirrer, condenser, thermometer, and dropping pump, 34 parts of phenol was melted, 3.5 parts of activated clay was added, the temperature was raised to 110 ° C., and 100 parts of styrene was added dropwise over 3 hours. Aging is performed at 110 to 120 ° C. for 1 hour. Thereafter, the mixture was filtered using diatomaceous earth to obtain styrenated phenol.
105 parts of the resulting styrenated phenol was placed in an autoclave equipped with a stirrer, thermometer and pressure cylinder, 0.2 part of potassium hydroxide was added and the temperature was raised to 135 ° C., and ethylene oxide 16.4 was obtained. Part was blown and reacted at 135 to 160 ° C. for 3 hours to obtain a styrenated phenol ethylene oxide (1.3 mol) adduct.

91 parts of the resulting styrenated phenol ethylene oxide (1.3 mol) adduct is placed in a 1 L Erlenmeyer flask, and 200 parts of chloroform and 51.5 parts of N, N'-dicyclohexylcarbodiimide are added and dissolved. After cooling to 0 ° C. and adding 0.06 part of dimethylaminopyridine, 25 parts of acrylic acid is gradually added dropwise while keeping the liquid temperature at 5 ° C. or lower. After completion of dropping, the mixture was stirred at a liquid temperature of 5 ° C. or lower for 10 hours, and then chloroform was removed to obtain a (meth) acryl compound (A-1). This corresponds to R ¹ = hydrogen atom, R ² = hydrogen atom, R ³ = hydrogen atom, n = 1.3, m = 2.8 in the general formula (1).

<Synthesis Example 2>
<Method for synthesizing (meth) acrylic compound (A-2)>
In a flask equipped with a stirrer, a condenser, a thermometer, and a dropping pump, 34 parts of phenol was melted, 3.5 parts of activated clay was added, the temperature was raised to 110 ° C., and 85 parts of α-methylstyrene was added for 3 hours. The solution is dropped over a period of 1 hour at 110 to 120 ° C. Thereafter, the mixture was filtered using diatomaceous earth to obtain α-methylstyrenated phenol.
90 parts of the resulting α-methylstyrenated phenol was placed in an autoclave equipped with a stirrer, thermometer and pressure cylinder, 0.2 part of potassium hydroxide was added, and the temperature was raised to 135 ° C. 33 parts were blown and reacted at 135 to 160 ° C. for 3 hours to obtain an α-methylstyrenated phenol ethylene oxide (3.0 mol) adduct.

134.5 parts of the resulting α-methylstyrenated phenol ethylene oxide (3.0 mol) adduct was placed in a 1 L Erlenmeyer flask, and 200 parts of chloroform and 51.5 parts of N, N′-dicyclohexylcarbodiimide were added. The solution was dissolved, cooled to 2 ° C., and 0.06 part of dimethylaminopyridine was added. 21.5 parts of methacrylic acid was gradually added dropwise while maintaining the liquid temperature at 5 ° C. or lower. After completion of dropping, the mixture was stirred at a liquid temperature of 5 ° C. or lower for 10 hours, and then chloroform was removed to obtain a (meth) acryl compound (A-2). This corresponds to R ¹ = methyl group, R ² = hydrogen atom, R ³ = methyl group, n = 3.0, m = 2.1 in the general formula (1).

<Comparative Synthesis Example 1>
<Method for producing (meth) acrylic compound (A′-1)>
A (meth) acrylic compound (A′-1) was obtained in the same manner as in Synthesis Example 1 except that ethylene oxide was changed to 150 parts. This corresponds to R ¹ = hydrogen atom, R ² = hydrogen atom, R ³ = hydrogen atom, n = 11.5, m = 2.8 in the general formula (1).

<Comparative Synthesis Example 2>
<Method for producing (meth) acrylic compound (A'-2)>
A (meth) acrylic compound (A′-2) was obtained in the same manner as in Synthesis Example 1 except that styrene was changed to 60 parts. This corresponds to R ¹ = hydrogen atom, R ² = hydrogen atom, R ³ = hydrogen atom, n = 2.3, m = 1.7 in the general formula (1).

<Comparative Synthesis Example 3>
<Method for producing sulfur atom-containing (meth) acrylic compound (A'-3)>
A flask equipped with a stirrer, a condenser, a thermometer, and a dropping pump was charged with 300 parts of toluene and 110 parts of phenyl mercaptan containing sulfur atoms, heated to 50 ° C., and stirred until uniform. Next, 155 parts of 2-methacryloxyethyl isocyanate (Karenz MOI: Showa Denko KK) and 0.1 part of bismuth catalyst (Neostan U-600: Nitto Kasei Co., Ltd.) were gradually added dropwise and stirred for 10 hours. did. Thereafter, toluene was removed to obtain a (meth) acrylic compound (A′-3) containing a sulfur atom.

<Synthesis Example 3>
<Method for producing urethane oligomer (C-1)>
In a reaction vessel equipped with a stirrer and an air introduction tube, 207 parts of a 2-mol adduct of bisphenol A ethylene oxide was charged and heated at 70 ° C. under reduced pressure to remove the contained water. After dehydration, 500 parts of ethyl acetate was added and homogenized, and the temperature was lowered to 50 ° C. or lower.
Next, 114 parts of isophorone diisocyanate (IPDI), 56 parts of xylylene diisocyanate (XDI), and 0.4 parts of a bismuth catalyst (Neostan U-600: manufactured by Nitto Kasei Co., Ltd.) as a urethanization catalyst were added, and the mixture was stirred at 75 ° C. Was reacted for 10 hours to obtain a urethane prepolymer having isocyanate groups at both ends.
After adding 43 parts of 2-hydroxyethyl acrylate to the obtained urethane prepolymer and reacting with air at 75 ° C. for 4 hours, the temperature was lowered to 50 ° C. or lower, and ethyl acetate was removed under reduced pressure at both ends. A urethane oligomer (C-1) having an acryloyl group was obtained. The number average molecular weight Mn of this urethane oligomer (C-1) was 1,800.

<Example 1>
In a container equipped with a stirrer, 50 parts of the (meth) acrylic compound (A-1) prepared in Synthesis Example 1, 20 parts of the urethane oligomer (C-1) prepared in Production Example 1, and 4 mol of bisphenol A ethylene oxide adduct 20 parts of diacrylate (Neomer BA-641: manufactured by Sanyo Chemical Industries), 5 parts of benzyl acrylate and 5 parts of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184: manufactured by Nagase Sangyo Co., Ltd.) as a photopolymerization initiator are added. And it was made to melt | dissolve uniformly at 50 degreeC, and the ultraviolet curable resin composition (Q-1) of this invention was obtained.

<Examples 2 and 3 and Comparative Examples 1 to 5>
UV curable resin compositions (Q-2) and (Q-3) of the present invention, and UV curable resin compositions of comparative examples in the same manner as in Example 1 with the raw materials and the number of parts listed in Table 1. (Q′-1) to (Q′-5) were obtained.

However, the symbols in Table 1 represent the following.
Aromatic polycyclic structure-containing (meth) acrylic compound (A′-4): 2-phenylphenoxy polyethoxy acrylate (NK ester A-LEN-10: manufactured by Shin-Nakamura Chemical Co., Ltd.)
Titanium oxide (OPTRAIK 1820Z: manufactured by Catalyst Chemical Industry Co., Ltd.)

<Performance evaluation>
As the performance evaluation of the ultraviolet curable resin compositions (Q-1) to (Q-3) and (Q′-1) to (Q′-5), the refractive index after photocuring, the haze after photocuring, The light resistance was evaluated by the following method.

<Refractive index after photocuring>
After the UV curable resin composition is applied on a glass plate with a thickness of 40 μm, it is covered with a PET film (trade name: Cosmo Shine A4300-150 μm: manufactured by Toyobo Co., Ltd.) and irradiated with UV light of 500 mJ / cm ² for photocuring. did. Thereafter, the PET film and the photocurable resin were released from the glass plate to obtain a resin film. The refractive index of this resin film was measured at 23 ° C. using a refractometer (DR-M2: manufactured by Atago Co., Ltd.).

<Haze after photocuring>
The haze of the resin film was measured with a haze measuring apparatus (300A: manufactured by Nippon Denshoku).

<Light resistance>
The resin film was irradiated with 60 W / m ² for 24 hours under the condition of 60 ° C. with a light resistance acceleration tester (SUV-131W: manufactured by Iwasaki Electric Co., Ltd.). From the L ^* value, a ^* value, and b ^* value described in JIS Z8729, the resin film before and after the irradiation was measured with a color difference meter (CM3600d: manufactured by Minolta Co.), the color difference ΔE was calculated by the following formula.

_{^{ΔE = ((L * 1 -L}} * 2) 2 + (a * 1 -a * 2) 2 + (b * 1 -b * 2) 2) 0.5

However, L ^* ₁ , a ^* ₁ , and b ^* ₁ represent the L ^* value, a ^* value, and b ^* value before the light resistance test, respectively. L ^* ₂ , a ^* ₂ , and b ^* ₂ are respectively L ^* value, a ^* value, and b ^* value after the light resistance test are represented.

UV curable resin compositions (Q-1) to (Q-3) of the present invention prepared in Examples 1 to 3 and UV curable resin compositions for comparison (Q ′) prepared in Comparative Examples 1 to 5 Table 1 shows the evaluation results of the photocured resins of (-1) to (Q′-5).

As is clear from Table 1, when the ultraviolet curable resin compositions of Examples 1 to 3 of the present invention are used for a transmission type screen by mold molding, they are excellent in transparency and light resistance while having a high refractive index. I understand.
On the other hand, Comparative Example 1 using a (meth) acrylic compound (A′-1) having a large number of added moles of alkylene oxide and a (meth) acrylic compound (A′-2) having a small number of introduced styrene skeletons were used. Comparative Example 2 has a small refractive index.
Comparative Example 3 using a (meth) acrylic compound (A′-3) containing a sulfur atom and Comparative Example 4 using a (meth) acrylic compound (A′-4) containing an aromatic polycyclic structure are as follows: There is a problem with poor light resistance.
It can be seen that Comparative Example 5 using titanium oxide for increasing the refractive index has a problem of high haze and poor transparency.

  Since the ultraviolet curable resin composition of the present invention has a high refractive index and excellent transparency and light resistance, a prism lens sheet, a diffusion lens sheet, a lenticular lens, etc. used for liquid crystal televisions, projection televisions, etc. It is useful as a transmissive screen used in

Claims (5)

An ultraviolet curable resin composition (Q) comprising a (meth) acrylic compound (A) represented by the following general formula (1) and a photopolymerization initiator (B) as essential components.

[In formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom or a methyl group, the average value of n is 0 to 10 and the average value of m is 2.1 to 5.0. Is the number of ]   The ultraviolet curable resin composition (Q) according to claim 1, further comprising a urethane oligomer (C) having a number average molecular weight of 1,000 to 10,000.   Furthermore, the ultraviolet curable resin composition (Q) of Claim 1 or 2 containing the polyfunctional (meth) acryl compound (D) containing two or more (meth) acryl groups in a molecule | numerator.   The ultraviolet curable resin composition according to any one of claims 1 to 3, wherein the urethane oligomer (C) is a (meth) acrylate-containing urethane oligomer (C1) which is a reaction product of an organic isocyanate, a polyol and a hydroxyl group-containing (meth) acrylate. Things (Q).   The ultraviolet curable resin composition (Q) according to any one of claims 1 to 4, wherein the cured product by ultraviolet irradiation has a refractive index at 23 ° C of 1.560 or more.