JPH10324726A - Resin composition for optical material and its hardened material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new resin composition rapidly hardenable by ultraviolet rays, having excellent adhesiveness to a resin base material with slight discoloration of the hardened material and having high refractive index by making the composition contain a urethane (meth)acrylate having a specific structure, a diluent and methylbenzoyl formate. SOLUTION: This resin composition contains (A) a urethane (meth)acrylate as a reaction product of (i) a (meth)acrylate having a hydroxyl group in a molecule [e.g. 2-hydroxyethyl (meth)acrylate], (ii) an aromatic diisocyanate (e.g. tolylene diisocyanate) and (iii) a diol compound as an optional component, (B) a diluent (e.g. phenoxyethyl acrylate) and (C) methylbenzoyl formate as a photopolymerization initiator. Preferably, 25-85 wt.% of the component B and 0.1-15 wt.% of the component C are contained in the objective composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for an optical material suitable for a Fresnel lens, a lenticular lens and the like used for a video projector, a projection television, a liquid crystal display and the like, and a cured product thereof.

[0002]

2. Description of the Related Art Heretofore, this type of lens has been formed by a method such as a pressing method or a casting method. The former press method has poor productivity because it is manufactured by a cycle of heating, pressing and cooling. In addition, the latter casting method takes a long time to polymerize by pouring a monomer into a mold and requires a large number of molds. Recently, a lens mold and a transparent resin base material (for example, polycarbonate, PVC, polyester, Various methods have been proposed in which an ultraviolet-curable resin liquid for forming a lens portion is interposed between the ultraviolet-curable resin liquid and acrylic or styrene. (For example, Japanese Patent Application Laid-Open No. 61-177215,
1-2248707, JP-A-61-248708, JP-A-63-163330, JP-A-63-167301, JP-A-63-199302, JP-A-64-6935, etc.)

[0003]

In the technique of forming a lens portion by interposing an ultraviolet curable resin between a lens mold and a transparent resin substrate, there is not enough space between the lens portion and the transparent resin substrate. In many cases, adhesion cannot be obtained. In particular, when a resin containing methacrylic resin, which is excellent in transparency and weather resistance and is suitable as this kind of material, is used as a base material, the adhesiveness with an ultraviolet-curable resin is insufficient, so that the adhesiveness is low. Is strongly desired.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies and found that curing by ultraviolet rays is fast, that they have excellent adhesion to a resin substrate, especially methacrylic resin, and that The cured product has little coloring and has a high refractive index, and has completed the present invention. That is,
The present invention relates to (1) a compound having one hydroxyl group per minute (meth)
Urethane (meth) acrylate (A) which is a reaction product of acrylate (a), aromatic diisocyanate (b) and optionally diol compound (c) and has a bisphenolmethane structure in the molecule, diluent (B) and A resin composition for an optical material, comprising methylbenzoyl formate (C) as a photopolymerization initiator,
(2) The resin composition for an optical material according to (1), wherein the aromatic diisocyanate (b) is 4,4'-diphenylmethane diisocyanate, and (3) the (1), wherein the aromatic diisocyanate (b) is tolylene diisocyanate. (4) the urethane (meth) acrylate (A) contains a diol compound (c) as a reaction component, and the diol compound (c) is bisphenol F
The optical material resin composition according to (1), which is a polyalkyleneoxy glycol, (5) the urethane (meth) acrylate (A) contains a diol compound (c) as a reaction component, and the diol compound (c) is a polyalkyleneoxy glycol. (1) The resin composition for an optical material according to (1), which is bisphenol A polyalkyleneoxy glycol, (6) the urethane (meth) acrylate (A) contains a diol compound (c) as a reaction component, and the diol compound (C) is 2-butyl-2-ethylpropanediol, wherein the resin composition for an optical material according to (1), and (7) a cured product of the resin composition for an optical material according to (1) to (6). .

[0005] The resin composition of the present invention contains a urethane (meth) acrylate (A) having a bisphenolmethane structure in the molecule. As a specific example of urethane (meth) acrylate (A), (meth) acrylate (a) having one hydroxyl group in one molecule is reacted with aromatic diisocyanate (b) and diol compound (c) as an optional component. Can be obtained.

Specific examples of diol compounds that can be used include ethylene glycol, propylene glycol,
Methyl-1,5-pentanediol, 1,3-butylene glycol, neopentyl glycol, cyclohexane dimethylol, tricyclodecane dimethylol, 1,6
-Hexanediol, 2-butyl-2-ethyl-propanediol, bisphenol A poly (n = 4 to 15) ethoxy glycol, bisphenol A poly (n = 4-1)
5) Propoxy glycol, bisphenol F poly (n
= 2 to 15) ethoxy glycol, bisphenol F poly (n = 2 to 15) propoxy glycol, bisphenol A poly (n = 2 to 15) butoxy glycol, bisphenol F poly (n = 15) butoxy glycol, polytetramethylene glycol, Examples include polycaprolactone diol, polyester diol, and polycarbonate diol. Preferred examples include 2-butyl-2-ethylpropanediol, bisphenol A poly (n = 4 to 10) ethoxy glycol, bisphenol A poly (n = 4 to 10) propoxy glycol, and bisphenol F poly (n = 2). -10) ethoxy glycol, bisphenol F poly (n = 2 to 1)
0) Propoxy glycol and the like can be mentioned.

[0007] Specific examples of the aromatic diisocyanate (b) include 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, and xylylene diisocyanate. Preferred examples include 4,4'-diphenylmethane diisocyanate and tolylene diisocyanate.

Further, specific examples of (meth) acrylate (a) having one hydroxyl group in one molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (a). (Meth) acrylate, poly (n = 2 to 10) ethylene glycol mono (meth) acrylate, poly (n = 2 to 1)
0) propylene glycol mono (meth) acrylate,
Pentaerythritol tri (meth) acrylate and the like can be mentioned. Preferred examples include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and poly (n = 2 to 7) propylene glycol mono (meth) acrylate.

Preferred combinations of the reaction include a reaction product of 2-butyl-2-ethylpropanediol, 4,4'-diphenylmethane diisocyanate and 2-hydroxyethyl acrylate, and a reaction product of 4,4'-diphenylmethane diisocyanate and poly (n = 2-7) reaction product of propylene glycol monoacrylate, bisphenol A poly (n = 4 to 10) reaction product of ethoxy glycol, 4,4'-diphenylmethane diisocyanate and 2-hydroxyethyl acrylate, bisphenol F poly (n =
2 to 10) a reaction product of ethoxy glycol, tolylene diisocyanate and 2-hydroxyethyl acrylate,
Reaction product of bisphenol F poly (n = 2 to 10) ethoxy glycol, tolylene diisocyanate and 2-hydroxypropyl acrylate, bisphenol F poly (n = 2 to 10) ethoxy glycol, 4,4'-diphenylmenthadiisocyanate and 2 -Hydroxyethyl acrylate and the like.

The equivalent of the hydroxyl group of the component (C) is preferably 1.1 to 2.0 equivalents of the isocyanate group of the component (b). Particularly preferably, it is 1.5 to 2.0 equivalents.
This urethanation reaction can be performed according to procedures known to those skilled in the art. The reaction temperature of this urethanization reaction is usually from room temperature to 100 ° C, preferably from 50 to 85 ° C. Then, in the (meth) acrylate reaction, 0.9 to 1.5 equivalents of the hydroxyl group of the component (a) is added to 1 equivalent of the isocyanate group of the compound having a terminal isocyanate group obtained in the urethane-forming reaction. The reaction is preferably performed, and particularly preferably 1.0 to 1.1 equivalent. In this reaction, usually 50 to 2000 ppm of a polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, p-methoxyphenol and p-benzoquinone is added to the reaction mixture to prevent gelation due to radical polymerization during the reaction. Is preferred. The reaction temperature of the acrylate reaction is usually from room temperature to 100 ° C, preferably from 50 to 8 ° C.
5 ° C. Although the reaction between the isocyanate group and the hydroxyl group proceeds without a catalyst, it is preferable to use a conventional catalyst such as triethylamine, dibutyltin dilaurate, dibutyltin diacetate, or the like.

In the resin composition of the present invention, the amount of the component (A) is preferably in the range of 10 to 70% by weight, particularly preferably 20 to 60% by weight.

Specific examples of the diluent (B) include phenoxyethyl (meth) acrylate, phenyloxyethyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, acryloylmorpholine, 2-hydroxyethyl (meth) acrylate, -Hydroxy-
3-phenyloxypropyl (meth) acrylate, N
-Vinylcaprolactam, o-phenylphenyloxyethyl (meth) acrylate, o-phenylphenyloxyethyloxyethyl (meth) acrylate, tribromophenyloxyethyl (meth) acrylate, tribromobenzyl (meth) acrylate, bisphenol A poly ( n = 2 to 15) ethoxydi (meth) acrylate, bisphenol F poly (n = 2 to 15) ethoxydi (meth) acrylate, nonanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxytri (meth)
A (meth) acrylate monomer such as acrylate can be used. Preferred are phenoxyethyl acrylate, phenylpoly (n = 2 to 4) ethoxyacrylate, o-phenylphenyloxyethyl acrylate, and o-phenylphenylpoly (n = 2 to 4)
Ethoxy acrylate, tribromophenyloxyethyl acrylate, bisphenol A poly (n = 4-1
0) An acrylate monomer having a high refractive index, such as ethoxydiacrylate, and an acrylate monomer, such as 1,6-hexanediol diacrylate, which contributes to the improvement of adhesion can be given.

In the resin composition of the present invention, methylbenzoyl formate (C) is used as an essential component as a photopolymerization initiator. By using the component (C),
A cured product with less coloring can be obtained by ultraviolet irradiation. When a photopolymerization initiator other than the component (C) is used, the cured product of the resin composition is highly colored, and is difficult to use for optical applications.

In the resin composition of the present invention, the amount of the component (B) and the component (C) is from 25 to 8
It is preferably 5% by weight, particularly preferably 35 to 79% by weight. The component (C) is preferably from 0.1 to 15% by weight, particularly preferably from 0.5 to 10% by weight.

The resin composition of the present invention comprises the above (A) and (B)
And component (C) can be obtained by mixing and dissolving each component.

The resin composition of the present invention comprises, in addition to the above components,
Bisphenol A type epoxy acrylate, bisphenol F type epoxy acrylate, photopolymerization initiator other than the component (C) (for example, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) 2,4) , 4-trimethylpentylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, phenyl 2-hydroxy-2-propyl ketone, etc.), light stabilizers (eg, hindered amine compounds, etc.), plasticizers, release agents, defoamers, Leveling agent,
Antioxidants, polymerization inhibitors, antistatic agents, non-reactive polymers (eg, polyester elastomers, polyurethane elastomers, poly (meth) acrylate polymers, etc.) can also be used in combination.

The cured product of the resin composition of the present invention can be obtained by irradiating the resin composition of the present invention with ultraviolet rays according to a conventional method. Specifically, the resin composition for an optical material of the present invention is applied to, for example, a stamper having a shape of a Fresnel lens or a lenticular lens, and a layer of the ultraviolet-curable resin composition is provided. The transparent resin substrate is adhered, and in this state, the resin composition is cured by irradiating ultraviolet rays from the transparent resin substrate side with a high-pressure mercury lamp or the like, and then peeled off from the stamper. In this way, a Fresnel lens or a lenticular lens having a refractive index (25 ° C.) of usually 1.55 or more and 1.56 or more under preferable conditions is obtained.

[0018]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to the following Examples. In the following, “parts” means “parts by weight” unless otherwise specified. (Synthesis example of urethane (meth) acrylate (A)) Synthesis example 1 156 parts of 2-butyl-2-ethylpropanediol,
375 parts of 4,4'-diphenylmethane diisocyanate were charged and reacted at 85 ° C. for about 15 hours until the concentration of isocyanate groups became about 7.9%, and then 121.8 parts of 2-hydroxyethyl acrylate and 0.3 part of methoquinone.
The mixture was reacted at 85 ° C. for about 10 hours until the isocyanate group concentration became 0.3% or less to obtain urethane acrylate (A-1). The refractive index (25 ° C.) is 1.583
It was 6.

Synthesis Example 2 250 parts of 4,4'-diphenylmethane diisocyanate, 816 parts of poly (n = 6) propylene glycol monoacrylate, 0.3 part of dibutyltin dilaurate and 0.3 part of methoquinone were charged and heated at 85 ° C. The reaction was carried out for 30 hours until the concentration of the isocyanate group became 0.3% or less, to obtain a urethane acrylate (A-2). The refractive index (25 ° C.) was 1.5250.

Synthesis Example 3 288 parts of bisphenol F diethoxy glycol and 261 parts of tolylene diisocyanate were charged, and the mixture was heated at 85.degree.
The reaction was carried out for 5 hours until the concentration of isocyanate groups became about 7.65%. Then, 121.8 parts of 2-hydroxyethyl acrylate and 0.3 part of methoquinone were charged and the concentration of isocyanate groups was reduced to 0 at 85 ° C. for about 10 hours. The reaction was carried out until the content became 0.3% or less to obtain urethane acrylate (A-3). The refractive index (25 ° C.) was 1.5852.

Synthesis Example 4 668 parts of bisphenol A poly (n = 10) ethoxy glycol and 500 parts of 4,4'-diphenylmethane diisocyanate are charged, and the concentration of isocyanate groups becomes about 7.19% at 85 ° C. for about 15 hours. Then, 243.6 parts of 2-hydroxyethyl acrylate and 0.7 part of methquinone were charged and reacted at 85 ° C. for about 10 hours until the concentration of isocyanate groups became 0.3% or less, and urethane acrylate (A- 4) was obtained. Refractive index (25 ° C)
Was 1.5650.

Examples 1 to 4 and Comparative Examples 1 and 2 An ultraviolet-curable resin composition having a composition as shown in Table 1 (the numerical values indicate parts by weight) was applied to a Fresnel lens mold and a thickness of 2.5.
It was injected between a methacrylic resin-based substrate having a thickness of 2 mm and irradiated with ultraviolet rays in a conventional manner to cure the resin, thereby obtaining a Fresnel lens.
The evaluation in the examples was performed by the following method. (1) Releasability: difficulty in releasing the cured resin from the mold.・ ・ ・: Good mold releasability from the mold △: Slightly difficult to release ×: Difficult to release or mold remaining. (2) Mold reproducibility: The surface shape of the cured ultraviolet curable resin layer and the surface shape of the mold were observed. ○: good reproducibility ×: poor reproducibility (3) Adhesion: An ultraviolet-curable resin composition was coated on a transparent methacrylic resin-based substrate to a thickness of 200 μm, a width of 20 mm, and a length of 1.
50 mm, then apply a high pressure mercury lamp (80 w / cm,
Irradiation at 500 mj / cm ² (without ozone) was carried out to cure the test piece, and the peel strength was measured.
(Measurement method of peel strength: 90 ° peel strength of a cured resin film on a methacrylic resin-based substrate was measured by a tensile tester.
(Peeling speed 100 mm / min) ・ ・ ・ ·· Peel strength 2 kg / cm or more ・ ·· Peel strength 1-2 kg / cm ・ ・ ・ ·· Peel strength 0.5-1 kg / cm × ·· Peel Strength: 0.5 kg / cm or less (4) Restorability: After strongly pressing a 10 mm metal round bar directly onto the noodle released from the mold of the cured ultraviolet curable resin layer, the mark of the round bar is completely formed on the surface. The time until disappearance was measured. ◎: Disappeared instantaneously ・ ・ ・: Disappeared within 60 seconds △: Disappeared in 1 to 60 minutes ×: Not disappeared (5) Scratch resistance: cured A methacrylic resin-based substrate (width 100 mm,
(100 mm in length and 2.5 mm in thickness) was pressed vertically and reciprocated 10 times at intervals of about 100 mm at a speed of 1 reciprocation of about 1 second, and then the surface was observed for flaws. ◎ ・ ・ ・ ・ ・ ・ No scratches are observed ○ ・ ・ ・ ・ Several streak-like scratches are recognized △ ・ ・ ・ ・ Some band-like scratches are observed × ・ ・ ・ ・ Full band-like scratches Is recognized

(6) Colorability: The cured ultraviolet curable resin layer was observed.・ ・ ・: Coloring is small and there is no problem △: Slightly colored ×: Coloring is a large problem (7) Refractive index (25 ° C.): refractive index of cured ultraviolet curable resin (25 ° C.).

[0024]

Table 1 Composition and physical properties Example Comparative Example 1 2 3 4 1 2 ○ Composition Urethane acrylate (A-1) 30 30 obtained in Synthesis Example 1 Urethane acrylate (A-2) 30 obtained in Synthesis Example 2 Urethane acrylate (A-3) obtained in Synthesis Example 3 20 Urethane acrylate (A-4) obtained in Synthesis Example 4 35 R-561 25 20 28 25 20 OPP-1.5 10 20 50 10 10 20 BPE-10 25 25 20 25 25 HDDA 10 5 7 10 5 R-551 30 Phenyl 2-hydroxy-2-propyl ketone-1.5 1.5 2 33 Methyl benzoyl neformate 3 1.5 1.5 1--2,4,6-trimethyl Benzoyldiphenylphosphine oxide 0.1 0.1 0.1 0.1 0.1 − ○ Physical properties Releasability ○ ○ ○ ○ ○ ○ Adhesion ◎ ◎ ◎ ◎ ◎ ◎ Reproducibility ○ ○ ○ ○ ○ ○ Restoration ○ ◎ ○ ◎ ○ ◎ Scratch resistance ◎ ○ ○ ◎ ◎ ○ Colorability ○ ○ ○ ○ × × Refractive index (25 ℃) 1.556 1.551 1.583 1.555 1.555 1.550

As is clear from Table 1, the cured product of the resin composition of the present invention has low coloring, good releasability, mold reproducibility, adhesion, resilience, scratch resistance, and a refractive index ( 25 ℃)
Had a high refractive index of 1.55 or more.

[0026]

The cured product of the resin composition of the present invention has low coloring, has a high refractive index, has excellent adhesion to a substrate, and has good releasability, mold reproducibility, restorability, and scratch resistance. Suitable for Fresnel lens and lenticular lens.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C08G 18/32 C08G 18/32 A 18/67 18/67

Claims (7)

[Claims] 1. (Meth) having one hydroxyl group in one molecule
Urethane (meth) acrylate (A), which is a reaction product of acrylate (a), aromatic diisocyanate (b), and optionally diol compound (c) and has a bisphenolmethane structure in the molecule, diluent (B) And methylbenzoyl formate (c) as a photopolymerization initiator
The resin composition for optical materials characterized by containing. 2. The method according to claim 1, wherein the aromatic diisocyanate (b) is 4,4 '.
The resin composition for an optical material according to claim 1, which is -diphenylmethane diisocyanate. 3. The resin composition for an optical material according to claim 1, wherein the aromatic diisocyanate (b) is tolylene diisocyanate. 4. The optical material according to claim 1, wherein the urethane (meth) acrylate (A) contains a diol compound (c) as a reaction component, and the diol compound (c) is bisphenol F polyalkyleneoxy glycol. Resin composition. 5. The optical material according to claim 1, wherein the urethane (meth) acrylate (A) contains a diol compound (c) as a reaction component, and the diol compound (c) is bisphenol A polyalkyleneoxy glycol. Resin composition. 6. The method according to claim 1, wherein the urethane (meth) acrylate (A) contains a diol compound (c) as a reaction component, and the diol compound (c) is 2-butyl-2-ethylpropanediol. Resin composition for optical materials. 7. A cured product of the resin composition for optical materials according to claim 1.