JP5328003B2 - Resin composition, lens resin composition and cured product thereof - Google Patents

Description

  The present invention relates to an ultraviolet curable resin composition and a cured product thereof. More specifically, the present invention relates to a resin composition and a cured product particularly suitable for lenses such as a Fresnel lens, a lenticular lens, a prism lens, and a microlens.

  Conventionally, the above-described lens has been molded by a method such as a pressing method or a casting method. The former pressing method was poor in productivity because it was manufactured by heating, pressurizing and cooling cycles. Further, the latter casting method has a problem that it takes a long manufacturing time because a monomer is poured into a mold for polymerization, and a manufacturing cost increases because a large number of molds are required. In order to solve such a problem, various proposals have been made for using an ultraviolet curable resin composition (Patent Document 1, Patent Document 2, etc.).

  A method for producing a transmission screen by using these ultraviolet curable resin compositions has been somewhat successful. However, these conventional resin compositions have a problem of poor adhesion to the substrate and releasability from the mold. If the adhesion is poor, the types of substrates that can be used are limited, making it difficult to obtain the intended optical properties. If the releasability is poor, the resin remains in the mold at the time of mold release, and the mold cannot be used. In addition, a resin composition having good adhesion is likely to have poor release properties because the adhesion to the mold is also improved. On the other hand, a resin composition having good release properties also has a problem that adhesion is likely to be poor. Therefore, it is desired to provide a resin composition that can satisfy both the performance of adhesion to the substrate and the releasability from the mold.

In addition, these lens compositions used for transmission screens and the like are processed into a finer shape or thinner as a result of recent high-definition images, or roll-like sheets. In order to continuously process films and films, low-viscosity products tend to be required, but the composition of Patent Document 3 does not have such physical properties.
In addition, physical properties as a cured product tend to be required to have as high a glass transition temperature (Tg) as possible so that the change in physical properties is small even under a high temperature environment when using a transmission screen.
In response to the above requirements, it is difficult to combine high refractive index, Tg point, releasability, adhesion, and low viscosity, and there is a problem that a product satisfying all of the requirements cannot be obtained.

JP 63-167301 A JP-A 63-199302 Japanese Patent No. 3209554

  An object of the present invention is to provide a resin composition having a high refractive index and a low viscosity, and a cured product thereof, which are excellent in releasability, mold reproducibility and adhesion.

  As a result of intensive studies to solve the above problems, the present inventors have found that an ultraviolet curable resin composition having a specific composition and a cured product thereof can solve the above problems, and have completed the present invention.

That is, the present invention relates to the following (1) to (6).
(1) Urethane (meth) acrylate (A) which is a reaction product of aromatic organic polyisocyanate (a-1) and hydroxyl group-containing (meth) acrylate (a-2), o-phenylphenol polyethoxy (meth) acrylate A resin composition comprising (B) and a photopolymerization initiator (C).
(2) The aromatic organic polyisocyanate (a-1) is 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate or 1,3-xylylene diisocyanate, and a hydroxyl group-containing (meth) acrylate (a-2 ) Is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, or polyethylene glycol mono (meth) acrylate.
(3) Further described in (1) or (2) above, further comprising (meth) acrylate compound (D) other than urethane (meth) acrylate (A) and o-phenylphenol polyethoxy (meth) acrylate (B). Resin composition.

(4) The resin composition according to any one of (1) to (3), wherein the viscosity at 25 ° C. measured with an E-type viscometer is 500 mPa · s or less.
(5) The resin composition according to any one of (1) to (4), which is for lenses.
(6) A cured product having a refractive index of 1.55 or more at 25 ° C. obtained by curing the resin composition according to any one of (1) to (5).
(7) A lens using the cured product according to (6).

  The resin composition of the present invention has a low viscosity, is excellent in releasability, mold reproducibility, and adhesion, and its cured product has a high refractive index. Therefore, it is particularly suitable for Fresnel lenses, lenticular lenses, prism lenses, micro lenses and the like.

  The resin composition of the present invention comprises urethane (meth) acrylate (A), which is a reaction product of aromatic organic polyisocyanate (a-1) and hydroxyl group-containing (meth) acrylate (a-2), o-phenylphenol poly. An ethoxy (meth) acrylate (B) and a photoinitiator (C) are included.

  In the present invention, examples of the aromatic organic polyisocyanate (a-1) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, p-phenylene diisocyanate, 3, 3'-dimethyl-4,4'-diisocyanate, 6-isopropyl-1,3-phenyl diisocyanate, 1,5-naphthalene diisocyanate and the like can be mentioned. Of these, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and 1,3-xylylene diisocyanate are preferable.

  Examples of the hydroxyl group-containing (meth) acrylate (a-2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, polyethylene glycol mono ( (Meth) acrylate, polypropylene glycol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, ε-caprolactone adduct of 2-hydroxyethyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, etc. Can be mentioned. Of these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and polyethylene glycol mono (meth) acrylate are preferable.

  The urethane (meth) acrylate (A) contained in the resin composition of the present invention is synthesized by a conventional method using an aromatic organic polyisocyanate (a-1) and a hydroxyl group-containing (meth) acrylate (a-2). Can be obtained. That is, for example, a urethane (meth) acrylate (A) can be obtained by adding a hydroxyl group-containing (meth) acrylate (a-2) to an aromatic organic polyisocyanate (a-1).

In synthesizing the urethane (meth) acrylate (A), 0.95 of hydroxyl groups in the hydroxyl group-containing (meth) acrylate (a-2) per equivalent of isocyanate groups in the aromatic organic polyisocyanate (a-1) component. It is preferable to react -1.1 equivalent, and 60-100 degreeC of reaction temperature is preferable. In order to accelerate these reactions, for example, amines such as triethylamine and benzylmethylamine, and dilaurate compounds such as dibutyltin dilaurate and dioctyltin dilaurate can be used as a catalyst. The amount of the catalyst added is preferably about 0.001 to 5% by weight, particularly preferably about 0.01 to 1% by weight, based on the entire reaction mixture.
In order to prevent polymerization during the reaction, for example, a polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, p-methoxyphenol, p-benzoquinone or the like can be used. The addition amount of the polymerization inhibitor is preferably 0.001 to 5% by weight, particularly preferably 0.01 to 1% by weight, based on the whole reaction mixture.
In addition, in the resin composition of this invention, urethane (meth) acrylate (A) may be used independently and may be used in mixture of multiple types.

  The resin composition of the present invention contains o-phenylphenol polyethoxy (meth) acrylate (B). The o-phenylphenol polyethoxyacrylate (B) is preferably a compound having an average number of ethoxy structure repeats of 1 to 3, and reacting a reaction product of o-phenylphenol and ethylene oxide with (meth) acrylic acid. Can be obtained. A reaction product of o-phenylphenol and ethylene oxide can be obtained by a known method, and then preferably in the presence of an esterification catalyst such as p-toluenesulfonic acid or sulfuric acid, or a polymerization inhibitor such as hydroquinone or phenothiazine. O-phenylphenol polyethoxy acrylate by reacting with (meth) acrylic acid in the presence of solvents (eg toluene, cyclohexane, n-hexane, n-heptane, etc.), preferably at a temperature of 70-150 ° C. (B) is obtained. The use ratio of (meth) acrylic acid is 1 to 5 mol, preferably 1.05 to 2 mol, with respect to 1 mol of the reaction product of p-phenylphenol and ethylene oxide. An esterification catalyst is 0.1-15 mol% with respect to the (meth) acrylic acid to be used, Preferably it is 1-6 mol%.

  Furthermore, in addition to the urethane (meth) acrylate (A) and o-phenylphenol polyethoxyacrylate (B) listed above, the adhesion of the resin composition of the present invention obtained, the glass transition temperature (Tg), In consideration of hardness and the like, the (meth) acrylate compound (D) other than the component (A) and the component (B) may be used alone or in combination of two or more. Examples of the (meth) acrylate compound (D) include (meth) acrylate monomers and (meth) acrylate oligomers.

Examples of the (meth) acrylate monomer include acryloylmorpholine, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexane-1,4-dimethanol mono (meth) acrylate, tetrahydrofurfuryl ( (Meth) acrylate, phenoxyethyl (meth) acrylate, phenyl polyethoxy (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, p-cumylphenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, Tribromophenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, bisphenol A polyethoxydi (meth) acrylate, bisphenol A polypropoxydi (meth) acrylate, bisphenol F polyethoxydi (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloxyethyl) isocyanurate, Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol hex (Meth) acrylate, tripentaerythritol penta (meth) acrylate, di (meth) acrylate of ε-caprolactone adduct of hydroxypentylglycolate (for example, KAYARAD HX-220, HX manufactured by Nippon Kayaku Co., Ltd.) -620), trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxytri (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate.
Among them, the resin composition of the present invention has a low viscosity and good adhesion of the cured product, such as acryloylmorpholine, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) acrylate, 1,4-butanediol di (meth) acrylate. 1,6-hexanediol di (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate or the like Bifunctional (meth) acrylate monomers are suitable.

  Examples of the (meth) acrylate oligomer include epoxy (meth) acrylate and polyester (meth) acrylate.

  Epoxy (meth) acrylates include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, terminal glycidyl ether of bisphenol A propylene oxide adduct, and fluorene epoxy resin and (meth) Examples include a reaction product with acrylic acid.

Examples of the polyester (meth) acrylate include a polyester diol which is a reaction product of the above diol compound and the above dibasic acid or an anhydride thereof, and a reaction product of (meth) acrylic acid.
Of these, urethane (meth) acrylate and polyester (meth) acrylate other than the component (A) are suitable for the resin composition of the present invention.

  Examples of the photopolymerization initiator (C) contained in the resin composition of the present invention include benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenone, 2,2-diethoxy- 2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2 Acetophenones such as methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one; 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-chloroanthraquinone, 2-amyl Anthraquinones such as nthraquinone; thioxanthones such as 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone, 4-benzoyl-4′- Benzophenones such as methyldiphenyl sulfide and 4,4′-bismethylaminobenzophenone; phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide Etc. Preferable examples include 2-hydroxy-2-methyl-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone. In addition, in the resin composition of this invention, a photoinitiator (C) may be used independently and may be used in mixture of multiple types.

  The use ratio of each component of the resin composition of the present invention is determined in consideration of a desired refractive index, glass transition temperature, viscosity, and the like, but the component (A) + component (B) + component (D) is 100 weights. In the case of parts, the component (A) is preferably used in an amount of 5 to 50 parts by weight, particularly preferably 5 to 30 parts by weight. Component (B) is preferably used in an amount of 30 to 95 parts by weight, particularly preferably 50 to 90 parts by weight. Component (D) is 0 to 50 parts by weight, preferably 0 to 20 parts by weight. Component (C) is preferably used in an amount of 0.1 to 10 parts by weight, particularly preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the total amount of component (A) + component (B) + component (D). Part.

  The resin composition of the present invention can contain a release agent, an antifoaming agent, a leveling agent, a light stabilizer, an antioxidant, a polymerization inhibitor, an antistatic agent and the like in addition to the above components. Furthermore, polymers such as acrylic polymer, polyester elastomer, urethane polymer and nitrile rubber can be added as necessary.

The resin composition of the present invention can be prepared by mixing and dissolving each component according to a conventional method. For example, each component can be prepared in a round bottom flask equipped with a stirrer and a thermometer and stirred at 40 to 80 ° C. for 0.5 to 6 hours.
As the resin composition of the present invention, a composition having a viscosity of 500 mPa · s or less at 25 ° C. measured using an E-type viscometer TV-200 (Toki Sangyo) is preferable.

  A cured product obtained by curing the resin composition of the present invention by irradiating with ultraviolet rays according to a conventional method is also included in the present invention. The cured product is obtained by applying the resin composition of the present invention on a stamper having a shape such as a Fresnel lens, a lenticular lens, or a prism lens, preferably without a solvent, and providing a layer of the resin composition. A back sheet (for example, a substrate or film made of polymethacrylic resin, polycarbonate resin, polystyrene resin, polyester resin, or a blend of these polymers) is adhered on the substrate, and then from the side of the rigid transparent substrate After the resin composition is cured by irradiating ultraviolet rays with a high pressure mercury lamp or the like, the cured product is peeled off from the stamper. Moreover, it can also carry out by a continuous process as these applications.

  In this way, a lens such as a Fresnel lens, a lenticular lens, a prism lens, or a micro lens having a refractive index (25 ° C.) of 1.55 or more and excellent in releasability, mold reproducibility, adhesion, and light resistance can be obtained. These lenses are also included in the present invention. The refractive index can be measured with an Abbe refractometer (model number: DR-M2, manufactured by Atago Co., Ltd.).

  The resin composition of the present invention is useful for lenses such as Fresnel lenses, lenticular lenses, prism lenses, and micro lenses, but is also useful for various coating agents, adhesives, and the like.

  Next, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited at all by the following examples.

Synthesis Example 1 Synthesis of Urethane (Meth) acrylate (A) In a drying container, 139.3 parts of 2,4-tolylene diisocyanate, 0.05 part of di-n-butyltin dilaurate and 0.16 part of methoquinone were put at 40 ° C. The temperature was raised to and stirred. To this, 185.6 parts of 2-hydroxyethyl acrylate was added dropwise over 1 hour while confirming heat generation, and reacted at 80 ° C. for 1 to 2 hours. The isocyanate value after the reaction was 0.1 or less, indicating that the reaction was almost quantitatively completed.

  The ultraviolet curable resin composition of this invention and hardened | cured material were obtained by the composition (a numerical value shows a weight part) as shown in the following examples. The evaluation method and evaluation criteria for the resin composition and the cured film were as follows.

(1) Viscosity: Measured at 25 ° C. using an E-type viscometer TV-200 (Toki Sangyo Co., Ltd.).
(2) Releasability: Difficulty when releasing the cured resin from the mold. ○ ... Good release from the mold. A certain X ·················································································· (3) Mold reproducibility
○ ... Good reproducibility × ... Poor reproducibility

(4) Adhesiveness: A test piece was prepared by applying a resin composition on a substrate to a film thickness of about 50 μm and then irradiating it with a high-pressure mercury lamp (80 W / cm, ozone-less) at 1000 mJ / cm ^2. The adhesion was evaluated according to JIS K5600-5-6.
In the evaluation results, 0 to 2 were evaluated as ○, and 3 to 5 as ×.

(5) Refractive index (25 ° C.): The refractive index (25 ° C.) of the cured ultraviolet curable resin layer was measured with an Abbe refractometer (model number: DR-M2, manufactured by Atago Co., Ltd.).
(6) Glass transition temperature (Tg): The Tg point of the cured ultraviolet curable resin layer was measured with a viscoelasticity measurement system DMS-6000 (manufactured by Seiko Electronics Co., Ltd.), a tensile mode, and a frequency of 1 Hz.

Example 1
15 parts of urethane acrylate obtained in Synthesis Example 1 as component (A), 65 parts of o-phenylphenol monoethoxy acrylate as component (B), 2-hydroxy-2-methyl-1-phenylpropane-1 as component (C) -3 parts of ON and 20 parts of acryloylmorpholine as component (D) were heated to 60 ° C and mixed to obtain a resin composition of the present invention. The viscosity of this resin composition was 155 mPa · s. Moreover, the refractive index (25 degreeC) of the film | membrane which hardened this resin composition was 1.591, and the glass transition temperature (Tg) was 61 degreeC.
This resin composition is applied on a lens mold so that the film thickness is 50 μm, and an easy-adhesion PET film (Toyobo Cosmo Shine A4300, 100 μm thickness) is adhered thereon as a base material, and then a high pressure is applied thereon. Curing was carried out by irradiating with an ultraviolet ray of 1000 mJ / cm ^{2 with} a mercury lamp, followed by peeling to obtain a prism lens.
Evaluation results: releasability: ○, mold reproducibility: ○, adhesion: ○.

Example 2
10 parts of urethane acrylate obtained in Synthesis Example 1 as component (A), 72 parts of o-phenylphenol monoethoxy acrylate as component (B), 2-hydroxy-2-methyl-1-phenylpropane-1 as component (C) -3 parts of ON, 13 parts of acryloylmorpholine as component (D), and 5 parts of tetrahydrofurfuryl acrylate were heated to 60 ° C and mixed to obtain a resin composition of the present invention. The viscosity of this resin composition was 90 mPa · s. Further, the refractive index (25 ° C.) of the film obtained by curing the resin composition was 1.591, and the glass transition temperature (Tg) was 60 ° C.
This resin composition is applied on a lens mold so as to have a film thickness of 50 μm, and a polycarbonate film having a thickness of 50 μm is adhered thereon as a base material, and further irradiated with 1000 mJ / cm ^{2 with} a high-pressure mercury lamp. After being cured by irradiation with an amount of ultraviolet rays, it was peeled off to obtain a prism lens.
Evaluation results: releasability: ○, mold reproducibility: ○, adhesion: ○.

Example 3
The resin composition obtained in Example 1 was applied on a lens mold so as to have a film thickness of 200 μm, and a methyl methacrylate-styrene copolymer base material was adhered thereon as a base material. A Fresnel lens was obtained by irradiating with an ultraviolet ray of 1000 mJ / cm ^{2 with} a high-pressure mercury lamp from above and curing it.
Evaluation results: releasability: ○, mold reproducibility: ○, adhesion: ○.

Comparative Example 1
According to Example 1 of Patent Document 1 (Japanese Patent Laid-Open No. 63-167301), 70 parts Aronics M-315 (tris (2-acryloyloxyethyl) isocyanurate), 30 parts tetrahydrofurfuryl acrylate, 1 as a photopolymerization initiator 3 parts of-(4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one was heated to 60 ° C. and mixed to obtain a comparative resin composition. The viscosity of this resin composition was 134 mPa · s. The refractive index (25 ° C.) of the film obtained by curing this resin composition was 1.52.
From this result, the composition of Comparative Example 1 has a lower refractive index than the composition of the present invention, and is not suitable for the production of the lenses of the present invention.

Comparative Example 2
According to the example of Patent Document 3 (Patent No. 3209554), urethane acrylate of Synthesis Example 1 of the document (neopentyl glycol and polyester diol of adipic acid, ethylene glycol, tolylene diisocyanate and 2-hydroxyethyl acrylate) And the compound (o-phenylphenol diethoxyacrylate) of Synthesis Example 3 of the literature, 30 parts of the above urethane acrylate, 15 parts of the above o-phenylphenol diethoxyacrylate, and KAYARAD R-551 (bisphenol A tetra). 45 parts of ethoxydiacrylate), 10 parts of tribromophenyl acrylate, and 3 parts of Irgacure 184 (1-hydroxycyclohexyl phenyl ketone) were heated and mixed at 60 ° C. to obtain a comparative resin composition. The viscosity of this resin composition was 4420 mPa · s. The refractive index (25 ° C.) of the film obtained by curing this resin composition was 1.574.
From this result, the composition of Comparative Example 2 has a higher viscosity than the composition of the present invention, and is unsuitable for fine processing and continuous processing of roll-shaped sheets and films.

  As is clear from the evaluation results of Examples 1 and 2 and Comparative Examples 1 and 2, the resin composition of the present invention has low viscosity, excellent releasability, mold reproducibility, and adhesion to a substrate, and its curing. The product has a high refractive index and a glass transition point (Tg) of 60 ° C. or higher. Therefore, it is suitable for a Fresnel lens, a lenticular lens, a prism lens, a micro lens, and the like. In particular, it is suitable for applications that require fine processing and manufacturing that includes processes that require continuous processing.

The ultraviolet curable resin composition and the cured product thereof according to the present invention are particularly suitable mainly for lenses such as Fresnel lenses, lenticular lenses, prism lenses, and micro lenses.

Claims (5)

2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate or 1,3-xylylene diisocyanate as aromatic organic polyisocyanate (a-1), and hydroxyl group-containing (meth) acrylate (a-2) Urethane (meth) acrylate (A) which is a reaction product with 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate or polyethylene glycol mono (meth) acrylate , o-phenylphenol monoethoxy (meth) acrylate A resin composition containing (B) and a photopolymerization initiator (C) and not containing a urethane (meth) acrylate other than the component (A) and a (meth) acrylate having a fluorene skeleton. The resin composition according to claim 1, wherein the viscosity at 25 ° C measured with an E-type viscometer is 500 mPa · s or less. The resin composition according to claim 1 or 2 , which is used for a lens. A cured product obtained by curing the resin composition according to any one of claims 1 to 3 . A lens using the cured product according to claim 4 .