JP3390099B2 - UV curable resin composition for Fresnel lens and transmission screen - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an ultraviolet curable resin composition suitable for producing optical parts such as Fresnel lenses. More specifically, the adhesiveness to a substrate containing a methyl methacrylate polymer or a copolymer of methyl methacrylate and another (meth) acrylate (hereinafter referred to as "methyl methacrylate (co) polymer") as a main component The present invention relates to an excellent ultraviolet curable resin composition and a transmission screen having a Fresnel lens sheet provided with a Fresnel lens made of the ultraviolet curable resin composition.

[0002]

2. Description of the Related Art Conventionally, as a UV curable resin used for manufacturing optical parts such as Fresnel lenses, a composition comprising an oligomer such as urethane (meth) acrylate or epoxy (meth) acrylate and a photosensitive monomer is used. It is known (Japanese Patent Laid-Open No. 3-157512, Japanese Patent Laid-Open No. 4-68010, etc.).

[0003]

However, the composition described in the above publication has poor adhesion to a substrate composed of a methyl methacrylate (co) polymer, and it is necessary to use a primer on the substrate side in order to improve the adhesion. was there. Further, it was difficult for the refractive index required when used for a Fresnel lens to exceed 1.55.

[0004]

Means for Solving the Problems The inventors of the present invention have excellent adhesion to a substrate containing a methyl methacrylate (co) polymer as a main component, excellent optical properties and physical properties of a cured product, and are excellent in optical components such as Fresnel lenses. As a result of studying a UV-curable resin composition that is easy to mold, it was found that the above performance is satisfied by blending a (meth) acrylate-based monomer with a specific polymer having a specified refractive index and molecular weight, and the present invention is obtained. Arrived That is, the present invention provides an ultraviolet curable resin composition for forming a Fresnel lens on a substrate containing a methyl methacrylate polymer or a copolymer of methyl methacrylate and another (meth) acrylate as a main component. As a resin composition, the following (A)-
Composition (A) containing (D): a mono- or di (meth) acrylate monomer (B) having a molecular weight of 80 to 200 and a boiling point at atmospheric pressure exceeding 150 ° C .: 2-hydroxy-3-butoxypropyl (meth) acrylate and / or 2-hydroxy-3-
Phenoxypropyl (meth) acrylate (C): D-line refractive index at 25 ° C. is 1.55 or more,
A polyester resin (D) having a number average molecular weight of 5,000 or more: a photopolymerization initiator; and a Fresnel lens sheet provided with a Fresnel lens made of a resin obtained by curing the composition. The screen.

Examples of (A) used in the present invention include mono (meth) acrylates and di (meth) acrylates having a molecular weight of 80 to 200 and a boiling point at atmospheric pressure of higher than 150 ° C. When the molecular weight of (A) exceeds 200, the adhesion to a substrate made of a methyl methacrylate (co) polymer deteriorates. Also, the boiling point of (A) is 150
If the temperature is lower than 0 ° C, the target product with stable performance cannot be produced because of high volatility.

Specific examples of the above-mentioned mono (meth) acrylate include phenoxydiethylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth).
Acrylate, glycidyl (meth) acrylate, 2-
Examples thereof include hydroxyethyl (meth) acrylate. Examples of the di (meth) acrylate include ethylene di (meth) acrylate, 1,2- and 1,3-propylene diacrylate.

Preferred among these are ethylene di (meth) acrylate, tetrahydrofurfuryl (meth) acrylate and mixtures thereof.

In the present invention, other (meth) acrylate monomers can be used in combination with (A) and (B).

Specific examples of the other (meth) acrylate monomers include nonylphenoxydiethylene glycol (meth) acrylate, dodecylphenoxydiethylene glycol (meth) acrylate, oxydiethylene di (meth) acrylate and 1,6-hexanediol di (meth). ) Acrylates, neopentyl glycol di (meth) acrylates, bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.), and di (meth) acrylates of these alkylene oxide adducts, trimethylolpropane di- and tri (meth) acrylates. ) Acrylate, tri- of pentaerythritol
And tetra (meth) acrylate, tri-, tetra-, penta- and hexa (meth) acrylates of dipentaerythritol.

In the present invention, (C) has a D-line refractive index of 1.55 or more at 25 ° C. and a number average molecular weight of 5,0.
It is a polyester resin of 00 or more.

Examples of the (C) include polyesters obtained by reacting a diol obtained by adding 2 to 20 moles of alkylene oxide to bisphenol A and a dicarboxylic acid and / or an anhydride thereof.

Examples of the above-mentioned alkylene oxide include ethylene oxide, propylene oxide, butylene oxide and mixtures thereof.

Examples of the above-mentioned dicarboxylic acid and its anhydride include succinic acid and its anhydride, adipic acid and its anhydride, isophthalic acid, terephthalic acid and a mixture of two or more thereof.

The above-mentioned polyester (C) can be produced under the usual conditions for producing polyester without using a catalyst or using an acid, alkali or metal catalyst.

The number average molecular weight of (C) is 5,000 or more. When the number average molecular weight of (C) is less than 5,000,
It is not preferable because the tackiness remains after the composition is UV-cured.

In the present invention, (A) and (B) are
A component containing a methyl methacrylate (co) polymer as a main component for improving adhesion to a substrate, and (C) is a component for imparting a viscosity suitable for workability.

In the composition of the present invention, (A):
The weight ratio of (B) :( C) is usually (20-40) :( 2
0-80): (10-60), preferably (30-5)
0) :( 30-60) :( 15-45). (A)
If the ratio is less than 20, a sufficient refractive index cannot be obtained, and if it exceeds 80, the viscosity of the system becomes too low and the workability deteriorates.
When the ratio of (B) is less than 20, the adhesion to a substrate containing a methyl methacrylate (co) polymer as a main component is poor, and 8
If it exceeds 0%, the viscosity of the system becomes too low and the workability deteriorates. If the ratio of (C) is less than 10, the desired viscosity cannot be obtained, and if it exceeds 60, the viscosity becomes too high and the casting workability deteriorates.

Photopolymerization initiator (D) used in the present invention
As, for example, benzoin alkyl ether, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-
Phenylpropan-1-one, benzophenone, methylbenzoyl formate, isopropylthioxanthone and mixtures of two or more thereof.

The amount of (D) is usually 0.1 to 10% by weight, based on the total weight of the compositions (A), (B) and (C),
It is preferably 0.5 to 6% by weight.

If desired, known additives such as a thermal polymerization inhibitor, a defoaming agent, a leveling agent and a coupling agent can be added to the composition of the present invention.

The composition of the present invention can be cured by irradiation with ultraviolet rays. The ultraviolet irradiation device is not particularly limited, and a known device can be used.

In the present invention, the substrate containing a methyl methacrylate-based (co) polymer as a main component is a homopolymer of methyl methacrylate or methyl methacrylate and other alkyl (meth) acrylates (alkyl having 1 to 1 carbon atoms).
The main component is a copolymer with 8). The (co)
The content of methyl methacrylate unit in the polymer is 70-
It is 100% by weight. When the content of the methyl methacrylate unit is less than 70% by weight, the adhesiveness with the cured product obtained from the composition of the present invention is deteriorated, which is not preferable.

The substrate constituting the Fresnel lens sheet in the present invention has a thickness of 0.5 to 5 by a known method such as injection molding, extrusion molding or cast molding of the (co) polymer.
A plate having a size of mm is used.

For the Fresnel lens sheet, the ultraviolet curable composition of the present invention is applied to a Fresnel lens molding die, and the substrate is pressure-laminated on the above-mentioned resin so as not to let air in. Can be produced by irradiating the sheet with the resin to cure the ultraviolet curable resin and then peeling the sheet from the mold.

[0025]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. "Parts" in the examples indicate parts by weight. Further, in the following, EO represents ethylene oxide and PO represents propylene oxide.

Example 1 Ethylene dimethacrylate 22 parts Polyester resin from 2 moles bisphenol A-PO adduct and maleic anhydride (number average molecular weight: 6,000, refractive index 1.56) 25 parts Bisphenol A-EO 4 moles addition Diacrylate 35 parts 2-Hydroxy-3-butoxypropyl methacrylate 15 parts 1-Hydroxycyclohexyl phenyl ketone 3 parts These are blended and uniformly dissolved to give a viscosity at 25 ° C. of 4,0.
A composition of the invention of 00 cps was obtained.

Example 2 Ethylenedimethacrylate 15 parts Tetrahydrofurfurylmethacrylate 15 parts Polyester resin from 2 moles of bisphenol A-EO adduct and adipic acid (number average molecular weight: 6,000, refractive index 1.55) 25 parts bisphenol A-EO 4 mol adduct diacrylate 17 parts 2-hydroxy-3-phenoxypropyl acrylate 25 parts Methyl benzoyl formate 3 parts These are blended and uniformly dissolved to obtain a viscosity at 25 ° C. of 3,0.
A composition of the invention of 00 cps was obtained.

Example 3 15 parts of ethylene dimethacrylate 15 parts of tetrahydrofurfuryl methacrylate 15 parts Polyester resin from bisphenol A-EO 4 mol adduct and phthalic anhydride (number average molecular weight: 6,000, refractive index 1.60) 25 parts Diacrylate of bisphenol A-EO 4 mole adduct 17 parts 2-hydroxy-3-phenoxypropyl methacrylate 25 parts Methyl benzoyl formate 3 parts These are blended and uniformly dissolved to have a viscosity at 25 ° C. of 2,8.
A composition of the invention of 00 cps was obtained.

Example 4 Ethylene dimethacrylate 22 parts Polyester resin from bisphenol A-PO2 mol adduct and maleic anhydride (number average molecular weight: 6,000, refractive index 1.58) 25 parts Bisphenol A-EO 4 mol addition Diacrylate 25 parts 2-hydroxy-3-phenoxypropyl acrylate 25 parts Methylbenzoyl formate 3 parts These are blended and uniformly dissolved to have a viscosity at 25 ° C. of 4,4.
A composition of the invention of 00 cps was obtained.

Comparative Example 1 Polyester resin consisting of 2 mol adduct of bisphenol A-PO and maleic anhydride (number average molecular weight: 6,000, refractive index 1.58) 25 parts Diacrylate of 4 mol adduct of bisphenol A-EO 25 Parts 2-hydroxy-3-phenoxypropyl acrylate 47 parts 1-hydroxycyclohexyl phenyl ketone 2 parts These are blended and uniformly dissolved to give a viscosity of 5,0 at 25 ° C.
A comparative composition of 00 cps was obtained.

Comparative Example 2 30 parts ethylene dimethacrylate 30 parts bisphenol A-PO2 mol addition product and a polyester resin from maleic anhydride (number average molecular weight: 6,000, refractive index 1.58) 25 parts bisphenol A-EO 4 mol addition Diacrylate 42 parts 1-hydroxycyclohexyl phenyl ketone 3 parts These are blended and uniformly dissolved to give a viscosity at 25 ° C of 3,4
A composition of the invention of 00 cps was obtained.

Test Example 1 A mold for a Fresnel lens having a size of 30 cm × 30 cm was coated with the compositions obtained in Examples 1 to 4 and Comparative Examples 1 and 2 to a thickness of 0.1.
It is applied to a thickness of 2 mm, and a 2 mm-thick substrate (Sumitex Chemicals: Sumipex HT) polymethylmethacrylate plate made of a methylmethacrylate copolymer is coated on it, and ultraviolet rays are irradiated from the substrate surface at 1,000 mJ / cm2. After that, it was taken out of the mold and a Fresnel lens was created.
Table 1 shows the adhesion and the refractive index of this Fresnel lens to the substrate.

[0033]

[Table 1]             Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2   −−−− ++ −−− + −−−− + −−−− + −−−− + −−−− + −−−−    Adhesion ｜ 100 ｜ 100 ｜ 100 ｜ 100 ｜ 0 ｜ 80   −−−− ++ −−− + −−−− + −−−− + −−−− + −−−− + −−−−    Refractive index ｜ 1.550 ｜ 1.554 ｜ 1.553 ｜ 1.560 ｜ 1.562 ｜ 1.540

(Note 1) Adhesiveness: A grid pattern (10 × 10) was put into a 1 mm width with a knife, cellophane tape was attached, and peeled at 90 degrees. At this time, the number of parts still attached to the grid is displayed. The display when the resin layer was not peeled at all was set to 100. Refractive index; value measured by Abbe refractometer (25 ° C)

Example 5 The ultraviolet curable resin composition shown in Example 1 was applied to a mold of a Fresnel lens which had been previously plated with chromium using a dispenser, and a thickness of a methyl methacrylate copolymer was applied. 2 mm substrate (Sumitomo Chemical: Sumipex H
T) is pressure-laminated so that air does not enter from the top of the resin filled in the mold, and ultraviolet rays are exposed to 30 times with a high pressure mercury lamp.
After irradiating for a second to cure the ultraviolet curable resin, the mold was peeled off to obtain a Fresnel lens sheet.

[0036]

The ultraviolet-curable resin composition for Fresnel lenses of the present invention has the following effects as compared with the conventional ones. (1) Excellent adhesion to a substrate containing a methyl methacrylate polymer or a copolymer of methyl methacrylate and another (meth) acrylate as a main component. (2) It is easy to mold an optical component such as a Fresnel lens. (3) The cured resin has excellent chemical resistance, toughness, heat resistance and cold resistance. The composition of the present invention is extremely useful especially as a material for a Fresnel lens because it exhibits the above effects.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsutomu Yamashita 1-11, Hitotsubashi-honcho, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd. (56) Reference JP-A-8-165315 (JP, A) JP-A-59-105068 (JP, A) JP-A-62-129364 (JP, A) JP-A-63-81301 ( JP, A) JP 61-76561 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 283/02

Claims (4)

(57) [Claims] 1. An ultraviolet curable resin composition for forming a Fresnel lens on a substrate comprising a methyl methacrylate polymer or a copolymer of methyl methacrylate and another (meth) acrylate as a main component, the ultraviolet curing A composition containing the following (A) to (D) as a functional resin composition. (A): a mono- or di (meth) acrylate monomer having a molecular weight of 80 to 200 and a boiling point at atmospheric pressure of higher than 150 ° C. (B): 2-hydroxy-3-butoxypropyl (meth) acrylate and / Or 2-hydroxy-3-
Phenoxypropyl (meth) acrylate (C): D-line refractive index at 25 ° C. is 1.55 or more,
Polyester resin (D) having a number average molecular weight of 5,000 or more: photopolymerization initiator 2. The composition according to claim 1, wherein (A) is ethylene di (meth) acrylate and / or tetrahydrofurfuryl (meth) acrylate. 3. The composition according to claim 1, wherein the weight ratio of (A) :( B) :( C) is (20-80) :( 20-80) :( 10-60). 4. A resin obtained by curing the composition according to claim 1 on a substrate containing a methyl methacrylate polymer or a copolymer of methyl methacrylate and another (meth) acrylate as a main component. A transmissive screen comprising a Fresnel lens sheet provided with a Fresnel lens comprising