JPH1180293A - Resin composition for optical material and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which can give lenses improved in adhesion to lens bases by including a urethane (meth)acrylate (A), an aromatic-group- containing mono(meth)acrylate (B), a reactive monomer (C) other than component B and a photopolymerization initiator. SOLUTION: Component A is a reaction product of a polyester diol being a diol having an average molecular weight of 200-750 (e.g. 3-methyl-1,5- pentanediol) with an organic diisocyanate and a hydroxy (meth)acrylate. Component B is exemplified by phenoxyethyl (meth)acrylate. Component C is exemplified by acryloylmorpholine. Component D is exemplified by 1-hydroxycyclohexyl phenyl ketone. The mixing ratio among components A to D is (10-70 wt.%)/(10-80 wt.%)/(5-60 wt.%)/(0.1-15 wt.%). This composition can give a cured product having a high refractive index, excellent mold release, adhesion, mold shape reproduction, recovery, and scratch resistance.

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 producing 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 requires a long production time because a monomer is poured into a mold and polymerizes it, and requires a large number of molds. Recently, a lens mold and a transparent resin base material (eg, polycarbonate, PVC, polyester) have been used. , Acrylic, styrene, etc.), various methods of interposing an ultraviolet-curable resin liquid for forming a lens portion have been proposed (for example, JP-A-61-177215, JP-A-61-215).
-248707, JP-A-61-248708, JP-A-6-248708
3-163330, 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 using a resin base material containing methacrylic resin which is excellent in transparency and weather resistance and is suitable as this kind of material,
Since the adhesiveness with an ultraviolet curing resin is insufficient, it is strongly desired to enhance the adhesiveness.

[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 was found to be a resin composition having excellent releasability, restoring property, and scratch resistance and a high refractive index, and completed the present invention. That is, the present invention relates to (1) a diol (a) having an average molecular weight of 200 to 750 as a polyester diol.
Urethane (meth) acrylate (A), which is a reaction product of an organic diisocyanate (b) and a hydroxyl group-containing (meth) acrylate (c), a mono (meth) acrylate having an aromatic group (B), and a component other than the component (B) A resin composition for an optical material, comprising: a reactive monomer (C) and a photopolymerization initiator (D); (2) an organic diisocyanate (b)
Is a resin composition for an optical material according to (1), wherein (3) the photopolymerization initiator (D) is a phosphine oxide-based photopolymerization initiator (D-1) and 1-hydroxycyclohexylphenyl ketone and / or Or a mixture with 2-hydroxy-2-methyl-1-phenylpropan-1-one (D-2), the resin composition for an optical material according to (1), and (4) a description from (1) to (3). (5) the cured product having a refractive index (25 ° C.) of 1.53 or more, (6) the cured product is a Fresnel lens or a lenticular lens (4) or (5) The cured product according to the above.

In the present invention, urethane (meth) acrylate (A) is used. This urethane (meth) acrylate (A) is a polyester diol having an average molecular weight of 20.
It can be obtained by reacting a diol (a) of 0 to 750 with an organic diisocyanate (b), and then reacting the reaction product with a hydroxyl group-containing (meth) acrylate (c). The average molecular weight of the diol (a) is determined by the hydroxyl value (measurement method: JIS K-0070-1966).
More required.

A polyester diol having an average molecular weight of 20
Examples of the diol (a) having 0 to 750 include diol compounds (eg, ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, neopentyl) Glycol, 1,6-hexanediol,
1,9-nonanediol, bisphenol A polyethoxydiol, cyclohexane-1,4-dimethylol, etc.) and dibasic acids (for example, succinic anhydride, adipic acid,
And polyester diol which is a reaction product with isophthalic acid and terephthalic acid. Preferred polyester diols (a) are themselves at room temperature (about 2
5 ° C.), and specifically, for example, diol compounds such as 3-methyl-1,5-pentanediol, neopentyl glycol, 1,3-butanediol and adipic acid, isophthalic acid, terephthalic acid And the like.

The organic diisocyanate (b) includes, for example, tolylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate and the like. Preferred examples include tolylene diisocyanate.

Examples of the hydroxyl group-containing (meth) acrylate (c) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
4-hydroxybutyl (meth) acrylate, poly (degree of polymerization: n = 2 to 10 as an average) ethylene glycol (meth) acrylate, poly (degree of polymerization: n as an average)
= 2 to 10) propylene glycol mono (meth) acrylate, pentaerythritol tri (meth) acrylate and the like. Preferably 2
-Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, poly (degree of polymerization: n = 2 as an average value)
~ 7) Propylene glycol monoacrylate and the like can be mentioned.

The equivalent of the hydroxyl group of the component (a) 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 urethanization reaction temperature is usually room temperature to 100 ° C, preferably 50 to 85 ° C. And
Next, in the (meth) acrylate reaction, 0.9 to 1.5 equivalents of the hydroxyl group of the component (c) are added to 1 equivalent of the isocyanate group of the compound having a terminal isocyanate group obtained in the urethane 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 100 ° C.
85 ° 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 laurate, dibutyltin diacetate and the like.

The polyester diol (a) constituting the urethane (meth) acrylate (A) used in the present invention preferably has an average molecular weight of 200 to 750, particularly preferably 200 to 500. When the average molecular weight is 200 or less, the adhesion to the substrate becomes insufficient, and the resilience becomes insufficient, which is not preferable. When the average molecular weight is 750 or more, the releasability is insufficient, which is not preferable.

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.

Examples of the mono (meth) acrylate (B) having an aromatic group include phenoxyethyl (meth) acrylate, phenyloxyethyloxyethyl (meth) acrylate, and 2-hydroxy-3-phenyloxypropyl (meth) acrylate. , 2-hydroxy-3
-(O-phenylphenyl) oxypropyl (meth) acrylate, o-phenylphenyloxyethyl (meth) acrylate, o-phenylphenyloxyethyloxyethyl (meth) acrylate, tribromophenyloxyethyl (meth) acrylate, tribromo Benzyl (meth) acrylate, bisphenol A poly (degree of polymerization: n = 2 to 15 on average) ethoxydi (meth)
Acrylate, bisphenol A poly (degree of polymerization: n = 2 to 15 on average), and (meth) acrylate monomers such as propoxydi (meth) acrylate can be exemplified.

The amount of component (B) used in the resin composition of the present invention is preferably in the range of 10 to 80% by weight, particularly preferably 20 to 60% by weight.

As the reactive monomer (C) other than the component (B), for example, acryloylmorpholine, isobornyl (meth) acrylate, 2-hydroxyethyl (meth)
Acrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol di (meth) acrylate,
Ε- of polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, neopentyl glycol hydroxypivalate
Examples of the caprolactone reactant include di (meth) acrylate (for example, KAYARAD HX-220, HX-620, etc .: manufactured by Nippon Kayaku Co., Ltd.). Preferable examples include acrylate monomers and the like that contribute to the improvement of adhesion, such as 1,6-hexane diacrylate and polyethylene glycol diacrylate.

In the resin composition of the present invention, the amount of component (C) used is preferably in the range of 5 to 60% by weight, particularly preferably 10 to 50% by weight.

As the photopolymerization initiator (D), for example, 1-
Hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one,
Methylbenzoyl formate, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4
6-trimethylbenzoyl) -phenylphosphine oxide and the like. Preferred are 1-hydroxycyclohexylphenyl ketone and / or 2-hydroxy-2-methyl-1-phenylpropan-1-one (D-2) and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,
Phosphine oxide photopolymerization initiators such as 6-trimethylbenzoyl) -phenylphosphine oxide (D-
1) and the like. (D-2) and (D-
The usage ratio of 1) is (D-2): (D-1) = 90 to 9.
9.5: preferably 0.5 to 10, particularly preferably 9
5-99.5: 0.5-5.

In the resin composition of the present invention, the amount of component (D) used is preferably in the range of 0.1 to 15% by weight, particularly preferably 0.5 to 10% by weight.

The resin composition of the present invention comprises the above (A)
The components (B), (C) and (D) are further optionally
Bisphenol A type epoxy (meth) acrylate, light stabilizer (for example, hindered amine compound), plasticizer, release agent, defoamer, leveling agent, antioxidant, polymerization inhibitor, antistatic agent, non-reactive polymer (E.g., polyester elastomer, polyurethane elastomer, poly (meth) acrylate polymer, etc.)
Can be obtained by mixing.

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 (ultraviolet curable resin composition) of the present invention is applied on a stamper having the shape of, for example, a Fresnel lens or a lenticular lens, and a layer of the ultraviolet curable resin composition is formed. Then, a transparent resin substrate is adhered on the layer, and in this state, the resin composition is cured by irradiating ultraviolet rays from a side of the transparent resin substrate with a high-pressure mercury lamp or the like, and then separated from the stamper. In this way, the normal refractive index (25 ° C)
Is 1.53 or more, and under preferable conditions, a Fresnel lens or lenticular lens having 1.56 or more is obtained. Examples of the material of the transparent resin plate include a polycarbonate resin, a polystyrene resin, a polyester resin, a polyacryl resin, and a mixed resin thereof.

[0020]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but it is needless to say that the present invention is not limited to the following examples. In the following, “parts” means “parts by weight” unless otherwise specified. (Example of synthesizing urethane (meth) acrylate (A))

Synthesis Example 1 Polyester diol 400 comprising 3-methyl-1,5-pentanediol and adipic acid and having an average molecular weight of 400
Parts, 261 parts of tolylene diisocyanate.
C. for about 15 hours at a concentration of isocyanate groups of about 6.35.
%, And then 122 parts of 2-hydroxyethyl acrylate and 0.4 part of methoquinone were charged, and 85 parts of
C. for about 10 hours until the isocyanate group concentration becomes 0.3% or less, urethane acrylate (A-1)
I got The refractive index (25 ° C.) was 1.512.

(Synthesis Example of Urethane Acrylate for Comparative Example) Synthesis Example 2 Polyester diol 20 comprising 3-methyl-1,5-pentanediol and adipic acid and having an average molecular weight of 2000
00 parts, 261 parts of tolylene diisocyanate
At 85 ° C. for about 15 hours, the concentration of isocyanate groups is about 1.
The mixture was reacted to 86%, and then 122 parts of 2-hydroxyethyl acrylate and 0.7 part of methoquinone were charged.
85 ° C. for about 10 hours, when the concentration of the isocyanate group is 0.3
% Of the urethane acrylate (A-
2) was obtained. The refractive index (25 ° C.) was 1.491.

Examples 1 and 2 Comparative Example 1 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 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 having a thickness of 200 μm and a width of 20 was coated on a transparent methacrylic resin-based substrate.
mm, 150 mm in length, and then a high pressure mercury lamp (8
(0 w / cm, ozoneless) at 500 mj / cm ² and cured to form a test piece, and the peel strength was measured. (Measurement method of peel strength: Peel strength at 90 ° C. of the cured resin film on the methacrylic resin-based substrate was measured by a tensile tester (peel speed: 100 mm / min). ···· 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 metal round bar having a diameter of 10 mm against the surface of the cured ultraviolet curable resin layer released from the mold, until the trace of the round bar on the surface completely disappears. Was measured. ◎ ・ ・ ・ ・ ・ ・ It disappeared instantly ○ ・ ・ ・ ・ It disappeared within 60 seconds △ ・ ・ ・ ・ It disappeared between 1 and 60 minutes × ・ ・ ・ ・ It did not disappear

(5) Scratch resistance: A methacrylic resin-based substrate (width 100 mm, length 100 mm, thickness 2.5 mm) is strongly pressed vertically against the surface of the cured ultraviolet curable resin layer released from the mold. After reciprocating 10 times at an interval of about 100 mm at a speed of about 1 second for one reciprocation, scratches on the surface were observed. ◎ ・ ・ ・ ・ ・ ・ No scratches are observed ○ ・ ・ ・ ・ Several streak-like scratches are recognized △ ・ ・ ・ ・ Some band-like scratches are observed × ・ ・ ・ ・ Full band-like scratches Is recognized

(6) Refractive index (25 ° C.): The refractive index (25 ° C.) of the cured ultraviolet curable resin was measured.

[0030]

Table 1 Example 1 Comparative Example 12 21 Urethane acrylate (A-1) 30 35 obtained in Synthesis Example 1 Urethane acrylate (A-2) 30 obtained in Synthesis Example 2 30 Phenoxyethyl acrylate 25 28 25 o- Phenylphenyloxyethyloxy ethyl acrylate 10 10 10 Bisphenol A poly (n = 10) ethoxydiacrylate 25 20 25 1,6-hexanediol diacrylate 10 7 10 1-Hydroxycyclohexylphenyl ketone 33 2-Hydroxy-2- Methyl-1-phenylpropan-1-one 3 bis (2,6-dimethoxybenzoyl) 2,4,4-trimethylpentylphosphine oxide 0.1 0.1 0.1 ──────────────────────── Release ○ ○ × adhesion ◎ ◎ ○ mold reproducibility ○ ○ ○ resilient ◎ ◎ ◎ scratch resistance ◎ ◎ ◎ refractive index (25 ℃) 1.531 1.536 1.527

As apparent from Table 1, the cured product of the resin composition of the present invention has excellent releasability, good adhesion, mold reproducibility, resilience, scratch resistance, and a refractive index (25 ° C.). ) Is 1.5
It had a high refractive index of 3 or more.

[0032]

The cured product of the resin composition of the present invention has a high refractive index, excellent releasability, good adhesion, mold reproducibility, resilience, and scratch resistance, and is suitable for Fresnel lenses and lenticular lenses. ing.

Claims (6)

[Claims] 1. A polyester diol having an average molecular weight of 20
Urethane (meth) acrylate (A) which is a reaction product of diol (a), organic diisocyanate (b) and hydroxyl group-containing (meth) acrylate (c), which is 0 to 750, mono (meth) acrylate having an aromatic group ( B), (B)
Reactive monomer other than component (C) and photopolymerization initiator (D)
The resin composition for optical materials characterized by containing. 2. The resin composition for an optical material according to claim 1, wherein the organic diisocyanate (b) is tolylene diisocyanate. 3. A photopolymerization initiator (D) comprising a phosphine oxide-based photopolymerization initiator (D-1) and 1-hydroxycyclohexylphenyl ketone and / or 2-hydroxy-2.
-Methyl-1-phenyl-propan-1-one (D-
The resin composition for an optical material according to claim 1, which is a mixture of 2). 4. A cured product of the resin composition for an optical material according to claim 1. 5. The cured product according to claim 4, which has a refractive index (25 ° C.) of 1.53 or more. 6. The cured product according to claim 4, wherein the cured product is a Fresnel lens or a lenticular lens.