阅读说明：本技术 可辐射固化树脂组合物 (Radiation curable resin composition ) 是由 筱原宣康 高桥诚一郎 于 2019-08-30 设计创作，主要内容包括：本发明提供用于形成初级覆盖层的可辐射固化树脂组合物,该可辐射固化树脂组合物能够形成具有优异的柔韧性和足够的机械强度的固化层。本发明涉及用于形成光纤的初级覆盖层的可辐射固化树脂组合物,其包含氨基甲酸酯低聚物、聚合引发剂和可自由基聚合的非氨基甲酸酯单体,所述氨基甲酸酯低聚物是聚醚基氨基甲酸酯预聚物和含有一个活泼氢基团的异氰酸酯反应性化合物的反应产物,所述异氰酸酯反应性化合物包括脂族醇和含烯属不饱和基团的异氰酸酯反应性化合物,并且该异氰酸酯反应性化合物中脂族醇的含量为24摩尔％或更高。(The present invention provides a radiation curable resin composition for forming a primary cover layer, which is capable of forming a cured layer having excellent flexibility and sufficient mechanical strength. The present invention relates to a radiation curable resin composition for forming a primary coating layer of an optical fiber, comprising a urethane oligomer, a polymerization initiator and a radical polymerizable non-urethane monomer, the urethane oligomer being a reaction product of a polyether-based urethane prepolymer and an isocyanate-reactive compound containing one active hydrogen group, the isocyanate-reactive compound comprising an aliphatic alcohol and an isocyanate-reactive compound containing an ethylenically unsaturated group, and the content of the aliphatic alcohol in the isocyanate-reactive compound being 24 mol% or more.)

1. A radiation curable resin composition for forming a primary coating layer of an optical fiber, comprising a urethane oligomer having an ethylenically unsaturated group, a radically polymerizable non-urethane monomer, and a polymerization initiator, wherein

The urethane oligomer having an ethylenically unsaturated group is a reaction product of a polyether-based urethane prepolymer and an isocyanate-reactive compound having one active hydrogen group,

the isocyanate-reactive compound comprises an aliphatic alcohol and an ethylenically unsaturated group-containing isocyanate-reactive compound, and

the aliphatic alcohol content of the isocyanate-reactive compound is 24 mole% or more.

2. The radiation curable resin composition according to claim 1, wherein the curing speed S defined by the following formula (1) is 15% or more.

Formula (1): s (%) ═ Y₂₀/Y₁₀₀₀×100

In the formula, Y₁₀₀₀And Y₂₀Is a cured film of the radiation curable resin composition having a Young's modulus at 23 ℃, Y₁₀₀₀And Y₂₀Respectively at a curing condition of 1J/cm²And 20mJ/cm²。

3. The radiation curable resin composition according to claim 1 or 2, wherein the curing conditions are 1J/cm²The cured film of the radiation curable resin composition of (a) has a Young's modulus at 25 ℃ of 0.8MPa or less.

4. The radiation curable resin composition according to any one of claims 1 to 3, wherein the radical polymerizable non-urethane monomer comprises at least one vinyl group-containing compound selected from a vinyl ester compound and a vinyl amide compound.

5. The radiation curable resin composition according to claim 4, wherein the vinyl amide compound comprises N-vinyl caprolactam.

6. The radiation curable resin composition according to claim 4 or 5, wherein

At least a part of the urethane oligomer having an ethylenically unsaturated group and/or the radical-polymerizable non-urethane monomer is a (meth) acryloyl group-containing compound, and

the ratio of the number of moles of the (meth) acryloyl group-containing compound to the number of moles of the vinyl group-containing compound is 1/1 to 10/1.

7. The radiation curable resin composition according to any one of claims 1 to 6, wherein

The urethane oligomer having an ethylenically unsaturated group and the radical-polymerizable non-urethane monomer contain an ethylenically unsaturated group, and

the ratio of the number of moles of monofunctional compound having one ethylenically unsaturated group to the number of moles of polyfunctional compound having two or more ethylenically unsaturated groups is from 2/1 to 100/1.

8. The radiation curable resin composition according to any one of claims 1 to 7, wherein

The urethane oligomer having an ethylenically unsaturated group or the radical-polymerizable non-urethane monomer includes a monofunctional (meth) acrylate and a polyfunctional (meth) acrylate, and

the ratio of the number of moles of the monofunctional (meth) acrylate to the number of moles of the polyfunctional (meth) acrylate in the radiation curable resin composition is 1/1 to 75/1.

9. The radiation curable resin composition according to any one of claims 1 to 8, wherein the urethane oligomer having an ethylenically unsaturated group has a number average molecular weight of 2000 or more.

10. The radiation curable resin composition according to any one of claims 1 to 9, wherein the urethane oligomer having an ethylenically unsaturated group comprises a monofunctional urethane (meth) acrylate oligomer and a difunctional urethane (meth) acrylate oligomer.

11. The radiation curable resin composition according to claim 10, wherein a ratio of the number of moles of the monofunctional urethane (meth) acrylate oligomer to the number of moles of the bifunctional urethane (meth) acrylate oligomer is 3/1 to 100/1.

12. The radiation curable resin composition according to any one of claims 1 to 11, wherein the urethane oligomer having an ethylenically unsaturated group comprises an alkoxysilyl group-containing urethane oligomer having one (meth) acryloyl group at one end and one alkoxysilyl group at the other end.

13. The radiation curable resin composition according to claim 12, wherein

The urethane oligomer having an ethylenically unsaturated group comprises a monofunctional urethane (meth) acrylate oligomer, and

a ratio of the number of moles of the alkoxysilyl group-containing urethane oligomer to the number of moles of the monofunctional urethane (meth) acrylate oligomer other than the alkoxysilyl group-containing urethane oligomer is 0.01/1 to 0.7/1.

14. The radiation curable resin composition according to claim 12 or 13, wherein

The urethane oligomer having an ethylenically unsaturated group comprises a bifunctional urethane (meth) acrylate oligomer, and

the ratio of the number of moles of the alkoxysilane group-containing urethane oligomer to the number of moles of the bifunctional urethane (meth) acrylate oligomer is from 0.2/1 to 20/1.

15. The radiation curable resin composition according to any one of claims 1 to 14, wherein the free radically polymerizable non-urethane monomer comprises a free radically polymerizable alkoxysilane.

16. The radiation curable resin composition according to claim 15, wherein the radical polymerizable alkoxysilane has a (meth) acryloyl group.

17. The radiation curable resin composition according to claim 15 or 16, wherein

The urethane oligomer having an ethylenically unsaturated group comprises an alkoxysilyl group-containing urethane oligomer having one (meth) acryloyl group at one end and one alkoxysilyl group at the other end, and

the molar ratio of the alkoxysilane group-containing urethane oligomer to the radical-polymerizable alkoxysilane is from 0.1/1 to 10/1.

18. The radiation curable resin composition according to any one of claims 1 to 17, further comprising a non-free radically polymerizable alkoxysilane.

19. The radiation curable resin composition according to claim 18, wherein

The urethane oligomer having an ethylenically unsaturated group comprises an alkoxysilyl group-containing urethane oligomer having one (meth) acryloyl group at one end and one alkoxysilyl group at the other end, and

the ratio of the number of moles of the alkoxysilane group-containing urethane oligomer to the number of moles of the non-radical-polymerizable alkoxysilane is from 0.01/1 to 4/1.

20. The radiation curable resin composition according to claim 18 or 19,

the free-radically polymerizable non-urethane monomer comprises a free-radically polymerizable alkoxysilane, and

the ratio of the number of moles of the radically polymerizable alkoxysilane to the number of moles of the non-radically polymerizable alkoxysilane is from 0.01/1 to 3/1.

21. The radiation curable resin composition according to any one of claims 18 to 20, wherein

The urethane oligomer having an ethylenically unsaturated group comprises: an alkoxysilyl group-containing urethane oligomer having one (meth) acryloyl group at one end and one alkoxysilyl group at the other end; and a radically polymerizable alkoxysilane, and

the free-radically polymerizable non-urethane monomer comprises a free-radically polymerizable alkoxysilane, and

the ratio of the total number of moles of the alkoxysilane group-containing urethane oligomer and the radical polymerizable alkoxysilane to the number of moles of the non-radical polymerizable alkoxysilane is from 0.05/1 to 4/1.

[ technical field ]

The present invention relates to a radiation curable resin composition.

[ background art ]

The optical fiber is composed of a glass fiber obtained by hot-melt spinning of glass and a covering layer provided above the glass fiber for protective reinforcement. For example, an optical fiber is produced by first forming a flexible primary coating layer (hereinafter also simply referred to as "primary coating layer") on the surface of a glass fiber, and then forming a highly rigid secondary coating layer (hereinafter also simply referred to as "secondary coating layer") on the primary coating layer. Also known are ribbon optical fibers or optical fiber cables having a plurality of optical fibers with a covering layer bonded using an adhesive material.

A method commonly used for forming a covering layer on glass fibers is, for example, coating the glass fibers with a liquid curable resin composition and curing it with heat or light (particularly, ultraviolet rays). As a resin composition for forming a primary coating layer, for example, PTL1 discloses a radiation curable composition combining a urethane oligomer produced by a specific production method and a compound having one ethylenically unsaturated group.

[ citation list ]

Japanese unexamined patent application publication No. 2012-111674

[ summary of the invention ]

When the optical fiber side is subjected to a local pressure, the core of the glass fiber at the portion subjected to the pressure is bent with a small curvature, often resulting in optical loss. From the viewpoint of minimizing such optical loss (also referred to as microbending loss), the primary cover layer preferably has sufficient flexibility. However, if the primary cover layer is made flexible, sufficient mechanical strength (breaking strength and elongation at break) may not be obtained.

Accordingly, it is an object of the present invention to provide a radiation curable resin composition for forming a primary cover layer, which is capable of forming a cured layer having excellent flexibility and sufficient mechanical strength.

[ means for solving problems ]

The present inventors have conducted extensive studies in order to achieve the object, and as a result, have found that a radiation curable resin composition capable of forming a cured layer having excellent flexibility and sufficient mechanical strength can be obtained by combining specific polymerizable compounds, thereby completing the present invention.

Specifically, the present invention provides a radiation curable resin composition for forming a primary coating layer of an optical fiber, comprising a urethane oligomer having an ethylenically unsaturated group, a radical polymerizable non-urethane monomer and a polymerization initiator, wherein the urethane oligomer having an ethylenically unsaturated group is a reaction product of a polyether-based urethane prepolymer and an isocyanate-reactive compound having one active hydrogen group, the isocyanate-reactive compound comprising an aliphatic alcohol and an isocyanate-reactive compound having an ethylenically unsaturated group, and the content of the aliphatic alcohol in the isocyanate-reactive compound is 24 mol% or more.

In the radiation curable resin composition, the curing speed S defined by the following formula (1) may be 15% or more.

Formula (1): s (%) ═ Y₂₀/Y₁₀₀₀×100

[ in the formula, Y₁₀₀₀And Y₂₀Young's modulus at 23 ℃ of a cured film of a radiation curable resin composition, Y₁₀₀₀And Y₂₀Respectively at a curing condition of 1J/cm²And 20mJ/cm²。]

In the radiation curable resin composition, the curing conditions were 1J/cm²The cured film of the radiation curable resin composition of (a) may have a Young's modulus at 25 ℃ of 0.8MPa or less.

The free-radically polymerizable non-urethane monomer may include at least one vinyl group-containing compound selected from a vinyl ester compound and a vinyl amide compound.

The vinyl amide compound may include N-vinyl caprolactam.

At least a portion of the urethane oligomer having an ethylenically unsaturated group and/or the radically polymerizable non-urethane monomer may be a (meth) acryloyl group-containing compound. In this case, the ratio of the number of moles of the (meth) acryloyl group-containing compound to the number of moles of the vinyl group-containing compound may be 1/1 to 10/1.

The urethane oligomer having an ethylenically unsaturated group and the radical polymerizable non-urethane monomer may have an ethylenically unsaturated group. In this case, the ratio of the number of moles of the monofunctional compound having one ethylenically unsaturated group to the number of moles of the polyfunctional compound having two or more ethylenically unsaturated groups may be 2/1 to 100/1.

The urethane oligomer having an ethylenically unsaturated group or the radical polymerizable non-urethane monomer includes a monofunctional (meth) acrylate and a polyfunctional (meth) acrylate, and the ratio of the number of moles of the monofunctional (meth) acrylate to the number of moles of the polyfunctional (meth) acrylate may be 1/1 to 75/1.

The number average molecular weight of the urethane oligomer having an ethylenically unsaturated group may be 2000 or more.

The urethane oligomer having an ethylenically unsaturated group may include a monofunctional urethane (meth) acrylate oligomer and a difunctional urethane (meth) acrylate oligomer.

The ratio of the number of moles of the bifunctional urethane (meth) acrylate oligomer to the number of moles of the monofunctional urethane (meth) acrylate oligomer may be 3/1 to 100/1.

The urethane oligomer having an ethylenically unsaturated group may include an alkoxysilyl group-containing urethane oligomer having a (meth) acryloyl group at one end and an alkoxysilyl group at the other end.

The ratio of the number of moles of the alkoxysilane group-containing urethane oligomer to the number of moles of the monofunctional urethane (meth) acrylate oligomer other than the alkoxysilane group-containing urethane oligomer may be 0.01/1 to 0.7/1.

The urethane oligomer having an ethylenically unsaturated group may include a bifunctional urethane (meth) acrylate oligomer. In this case, the ratio of the number of moles of the alkoxysilane group-containing urethane oligomer to the number of moles of the bifunctional urethane (meth) acrylate oligomer may be 0.2/1 to 20/1.

The free-radically polymerizable non-urethane monomers can include free-radically polymerizable alkoxysilanes.

The radical polymerizable alkoxysilane may have a (meth) acryloyl group.

The molar ratio of the alkoxysilyl group-containing urethane oligomer to the radical polymerizable alkoxysilane may be 0.1/1 to 10/1.

The radiation curable resin composition may further comprise a non-free radically polymerizable alkoxysilane.

The ratio of moles of alkoxysilane group-containing urethane oligomer to moles of non-radically polymerizable alkoxysilane may be 0.01/1 to 4/1.

The ratio of the number of moles of free radically polymerizable alkoxysilane to the number of moles of non-free radically polymerizable alkoxysilane can be from 0.01/1 to 3/1.

The ratio of the total moles of alkoxysilyl group-containing urethane oligomer and free-radically polymerizable alkoxysilane to the moles of non-free-radically polymerizable alkoxysilane may be from 0.05/1 to 4/1.

[ Effect of the invention ]

According to the present invention, a radiation curable resin composition for forming a primary cover layer, which is capable of forming a cured layer having excellent flexibility and sufficient mechanical strength, can be provided.

[ detailed description of the invention ]

Preferred embodiments of the present invention will now be described in detail. However, the present invention is not limited to the following embodiments.

The radiation curable resin composition of the embodiment is a radiation curable resin composition for forming a primary coating layer of an optical fiber, which includes a urethane oligomer having an ethylenically unsaturated group (hereinafter also simply referred to as "urethane oligomer"), a radical polymerizable non-urethane monomer, and a polymerization initiator. The phrase "primary coating for forming an optical fiber" may also refer to use as a primary material.

The radiation referred to herein is infrared ray, visible light, ultraviolet ray, X-ray, electron beam, α -ray, β -ray, γ -ray, etc., of which ultraviolet ray is particularly preferable.

The urethane oligomer is a reaction product of a polyether-based urethane prepolymer and an isocyanate-reactive compound having one active hydrogen group. Specifically, the urethane oligomer comprises a constituent derived from a polyether-based urethane prepolymer and an isocyanate-reactive compound containing one active hydrogen group.

The polyether-based urethane prepolymer is a reaction product of a polyether polyol and a polyisocyanate, and has an isocyanate group at a molecular end. The polyether urethane prepolymer may be the reaction product of an aliphatic polyether diol and a diisocyanate.

The aliphatic polyether diol is preferably an aliphatic polyether diol obtained by, for example, ring-opening copolymerization of polyethylene glycol, polypropylene glycol, polybutylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, or polydecamethylene glycol with two or more ion-polymerizable cyclic compounds.

Examples of such an ionically polymerizable cyclic compound include cyclic ethers such as ethylene oxide, propylene oxide, 1-butene oxide, isobutylene oxide, 3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monoxide, isoprene monoxide, vinyloxetane, vinyltetrahydrofuran, vinylcyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether and glycidyl benzoate.

Specific examples of the polyether diol obtained by ring-opening copolymerization of two or more of the above-mentioned ion-polymerizable cyclic compounds include a binary copolymer obtained by combination of tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and ethylene oxide, propylene oxide and ethylene oxide, or 1-butene oxide and ethylene oxide, and a ternary copolymer obtained by combination of tetrahydrofuran, 1-butene oxide and ethylene oxide.

Other substances that may be used include polyether diols obtained by ring-opening copolymerization of the above-described ion-polymerizable cyclic compounds with cyclic imines (e.g., ethyleneimine), cyclic lactone acids (e.g., β -propiolactone and glycolic acid lactide), or dimethylcyclopolysiloxane.

Aliphatic polyether diols are available as commercial products, for example PTMG650, PTMG1000 or PTMG2000 (all provided by Mitsubishi Chemical Corp), PPG400, PPG1000, EXCENOL720, 1020 or 2020 (all provided by Asahi-Olin, Ltd.), PEG1000, UNISAFE DC1100 or DC1800 (all provided by NOF Corp.), PPTG2000, PPTG1000, PTG400 or PTGL2000 (all provided by Hodogaya Chemical Co., Ltd.), Z-3001-4, Z-3001-5, PBG2000A, PBG2000B, BO/EO 4000 or EO/BO2000 (all provided by Dai-ichi Kogyo Seiyaku Co., Ltd.), or Ltd Acc), or alternatively, LAim 2220, 3201, 3205, 4200, 4220, 8200 or 12000 (all provided by Sumitomo Bay Co., Ltd.).

Among these aliphatic polyether diols, it is preferable to use a diol having a number average molecular weight of 1000 to 5000, which is a ring-opening polymer of one or more different ion-polymerizable cyclic compounds of 2 to 4 carbon atoms, from the viewpoint of satisfying both the high-speed coatability of the resin solution and the flexibility of the covering material. Preferred aliphatic polyether polyols include ring-opened polymers of one or more oxides selected from the group consisting of ethylene oxide, propylene oxide, 1-butene oxide and isobutylene oxide (number average molecular weight of 1000 to 4000). The most preferred aliphatic polyether diols are ring-opened polymers of propylene oxide (number average molecular weight of 1000 to 3000).

Examples of the diisocyanate include aromatic diisocyanates, alicyclic diisocyanates, and aliphatic diisocyanates. Examples of the aromatic diisocyanate include 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1, 3-xylylene diisocyanate, 1, 4-xylylene diisocyanate, 1, 5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3 '-dimethyl-4, 4' -diphenylmethane diisocyanate, 3,3 '-dimethylphenylene diisocyanate, 4,4' -biphenyl diisocyanate, bis (2-isocyanatoethyl) fumarate, 6-isopropyl-1, 3-phenyldiisocyanate, 4-diphenylpropane diisocyanate and tetramethylxylylene diisocyanate. Examples of the alicyclic diisocyanate include isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), hydrogenated diphenylmethane diisocyanate, hydrogenated methylenediphenyl diisocyanate, 2, 5-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane and 2, 6-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane. Examples of the aliphatic diisocyanate include 1, 6-hexane diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.

From the viewpoint of economy and obtaining a composition having stable quality, the diisocyanate is preferably an aromatic diisocyanate, and more preferably 2, 4-toluene diisocyanate or 2, 6-toluene diisocyanate. The diisocyanate may be used alone, or two or more kinds may be used in combination.

The isocyanate-reactive compound contains one active hydrogen group, and examples of the active hydrogen group include mercapto (-SH), hydroxy (-OH) and amino (-NH)₂)。

The isocyanate-reactive compounds include aliphatic alcohols and isocyanate-reactive compounds containing ethylenically unsaturated groups. Aliphatic alcohols and ethylenically unsaturated group-containing isocyanate-reactive compounds are compounds having one active hydrogen group. Ethylenically unsaturated groups include (meth) acryloyl, vinyl, vinylidene, and vinylidene groups. Throughout the specification, "(meth) acryloyl" means "acryloyl" and its corresponding "methacryloyl". The same applies to the expression "(meth) acrylate".

The ethylenically unsaturated group in the ethylenically unsaturated group-containing isocyanate-reactive compound is preferably a (meth) acryloyl group. The active hydrogen groups of the ethylenically unsaturated group-containing isocyanate-reactive compound are preferably hydroxyl groups. That is, the ethylenically unsaturated group-containing isocyanate reactive compound may be a compound having a (meth) acryloyl group and an active hydrogen group (active hydrogen group-containing (meth) acrylate), or may be a compound having a (meth) acryloyl group and a hydroxyl group (hydroxyl group-containing (meth) acrylate).

Examples of the hydroxyl group-containing (meth) acrylate include a hydroxyl group-containing (meth) acrylate having a hydroxyl group bonded to a primary carbon atom (also referred to as a primary hydroxyl group-containing (meth) acrylate), including a (meth) acrylate having a hydroxyl group bonded to a secondary carbon atom (also referred to as a secondary hydroxyl group-containing (meth) acrylate) and a hydroxyl group-containing (meth) acrylate having a hydroxyl group bonded to a tertiary carbon atom (also referred to as a tertiary hydroxyl group-containing (meth) acrylate). The hydroxyl group-containing (meth) acrylate may be a primary hydroxyl group-containing (meth) acrylate or a secondary hydroxyl group-containing (meth) acrylate from the viewpoint of reactivity with an isocyanate group.

Examples of the primary hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1, 6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, and trimethylolethane di (meth) acrylate.

Examples of the secondary hydroxyl group-containing (meth) acrylate include 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and 4-hydroxycyclohexyl (meth) acrylate, and compounds obtained by an addition reaction between a glycidyl group-containing compound such as alkyl glycidyl ether, allyl glycidyl ether, and glycidyl (meth) acrylate and (meth) acrylic acid.

The content of the ethylenically unsaturated group-containing isocyanate reactive compound in the isocyanate reactive compound may be 40 mol% or more, 45 mol% or more, or 50 mol% or more, and 60 mol% or less or 55 mol% or less from the viewpoint of more remarkably exhibiting the effect of the present invention.

The isocyanate reactive compound includes an aliphatic alcohol having a hydroxyl group as an active hydrogen group. The aliphatic alcohol may have 1 to 15, 5 to 12, or 6 to 10 carbon atoms. The carbon chain of the aliphatic alcohol may be straight or branched. Examples of the aliphatic alcohol include methanol, ethanol, propanol, butanol and 2-ethyl-1-hexanol. From the viewpoint of more remarkably exhibiting the effect of the present invention, the aliphatic alcohol may be methanol or 2-ethyl-1-hexanol.

The aliphatic alcohol content of the isocyanate-reactive compound is 24 mole% or more. From the viewpoint of more remarkably exerting the effect of the present invention, the aliphatic alcohol content of the isocyanate reactive compound may be 30 mol% or more, 35 mol% or more or 40 mol% or more, and may be 60 mol% or less, 55 mol% or less, 50 mol% or less or 45 mol% or less.

The isocyanate-reactive compound may further comprise an alkoxysilane having one active hydrogen group. Examples of the alkoxysilane having one active hydrogen group include N- (β -aminoethyl) - γ -aminopropyltrimethoxysilane, N- (β -aminoethyl) - γ -aminopropyltrimethyldimethoxysilane, γ -mercaptopropyltrimethoxysilane and γ -aminopropyltrimethoxysilane. The alkoxysilyl group-containing compound may be γ -mercaptopropyltrimethoxysilane, which is an alkoxysilane having a mercapto group as an active hydrogen group.

From the viewpoint of more remarkably exerting the effect of the present invention, the content of the alkoxysilane having one active hydrogen group in the isocyanate reactive compound may be 2 mol% or more or 3 mol% or more, and it may also be 10 mol% or less, 8 mol% or less, 7 mol% or less, 6 mol% or less or 5 mol% or less.

The urethane oligomer containing the reaction product of an aliphatic polyether diol and a diisocyanate as a polyether-based urethane prepolymer may include oligomers having structures represented by the following formulae (a1) and (a2) (hereinafter, such oligomers will also be referred to as "oligomer a 1" and "oligomer a 2").

A-(ICN-POL)n-ICN-A(a1)

A-(ICN-POL)n-ICN-R¹(a2)

In these formulae, ICN each independently represents a structure derived from a diisocyanate, POL each independently represents a structure derived from an aliphatic polyether diol, n each independently represents an integer of 1.0 or more, A each independently represents a structure derived from an ethylenically unsaturated group-containing isocyanate-reactive compound, and R¹Represents a structure derived from an aliphatic alcohol.

The letter n is 1.0 or greater and can be greater than 1.0 or 1.1 or greater, 1.3 or greater or 1.5 or greater, and 3.0 or less, 2.5 or less or 2.0 or less. For example, n may be 1.1 to 3.0, 1.3 to 2.5, or 1.5 to 2.0.

In addition to the oligomers a1 and a2, the urethane oligomer containing a reaction product of an aliphatic polyether diol and a diisocyanate as a polyether-based urethane prepolymer and an alkoxysilane having one active hydrogen group as an isocyanate-reactive compound may further contain an oligomer having a structure represented by the following formula (a3) (hereinafter also referred to as "oligomer a 3").

A-(ICN-POL)n-ICN-R²(a3)

In the formula, R²Represents a structure derived from an alkoxysilane having one active hydrogen group, and ICN, POL, n and a have the same definitions as described above.

In addition to the oligomers a1 to a3, the urethane oligomer may or may not contain an oligomer (oligomer a4) having a structure represented by the following formula (a 4).

R¹-(ICN-POL)n-ICN-R¹(a4)

Wherein ICN, POL, n, A and R¹Have the same definitions as above.

The urethane oligomer may include a urethane (meth) acrylate oligomer having a (meth) acryloyl group as an ethylenically unsaturated group. The urethane oligomer may further include a monofunctional urethane (meth) acrylate oligomer having one (meth) acryloyl group as an ethylenically unsaturated group (corresponding to the oligomers a2 and a3), and a bifunctional urethane (meth) acrylate oligomer having two (meth) acryloyl groups as an ethylenically unsaturated group (corresponding to the oligomer a 1).

The ratio of the number of moles of the monofunctional urethane (meth) acrylate oligomer to the number of moles of the difunctional urethane (meth) acrylate oligomer may be 3/1 to 100/1, 5/1 to 75/1, 7/1 to 50/1, or 10/1 to 35/1.

The urethane oligomer may include, as a monofunctional urethane (meth) acrylate oligomer, an alkoxysilane group-containing urethane oligomer having one (meth) acryloyl group at one end and one alkoxysilane group at the other end (corresponding to oligomer a 3).

The ratio of the number of moles of the alkoxysilane group-containing urethane oligomer to the number of moles of the monofunctional urethane (meth) acrylate oligomer other than the alkoxysilane group-containing urethane oligomer may be 0.01/1 to 0.7/1, 0.02/1 to 0.5/1, 0.03/1 to 0.25/1, or 0.05/1 to 0.15/1.

The ratio of the number of moles of the alkoxysilane group-containing urethane oligomer to the number of moles of the bifunctional urethane (meth) acrylate oligomer may be 0.2/1 to 20/1, 0.5/1 to 10/1, or 1/1 to 5/1.

The number average molecular weight (Mn) of the urethane oligomer may be 2000 or more, 3000 or more, 4000 or more, or 5000 or more, and may be 2000 to 10000, 3000 to 9000, or 5000 to 8000. The number average molecular weight is a value measured by gel permeation chromatography and converted according to a standard polystyrene calibration curve.

The urethane oligomer content may be 30% by mass or more, 35% by mass or more, 50% by mass or more, 60% by mass or more, or 70% by mass or more from the viewpoint of allowing the flexibility and mechanical strength of the cured layer to be further improved, and may be not higher than 90% by mass, not higher than 85% by mass, or not higher than 83% by mass relative to 100% by mass of the total amount of the radiation-curable resin composition from the viewpoint of easily obtaining a radiation-curable resin composition having a suitable viscosity.

The urethane oligomer can be prepared, for example, by reacting a polyether-based urethane prepolymer, an aliphatic alcohol, and an ethylenically unsaturated group-containing isocyanate-reactive compound. For example, after reacting the polyether-based urethane prepolymer, the ethylenically unsaturated group-containing isocyanate reactive compound, and, if necessary, the alkoxysilane having one active hydrogen group, an aliphatic alcohol may be added at an aliphatic alcohol content of 24 mol% or more in the isocyanate reactive compound, and reacted to form a urethane oligomer.

If desired, a urethanization catalyst may also be used in the production of the urethane oligomer. Examples of the carbamation catalyst include copper naphthenate, cobalt naphthenate, zinc naphthenate, dibutyltin dilaurate, dioctyltin dilaurate, triethylamine, 1, 4-diazabicyclo [2.2.2] octane and 2,6, 7-trimethyl-1, 4-diazabicyclo [2.2.2] octane. The urethane-forming catalyst may be used in an amount of 0.01 to 1% by mass relative to the total amount of the reaction product. The reaction temperature is usually 5 to 90 ℃ and the reaction is most preferably carried out at 10 to 80 ℃.

The radiation curable resin composition further includes a free radically polymerizable non-urethane monomer. The free radically polymerizable non-urethane monomers used may be ethylenically unsaturated group-containing monomers. The ethylenically unsaturated group can be any of the groups described above. The free radically polymerizable non-urethane monomers used may be of a single type or a combination of two or more.

The radically polymerizable non-urethane monomer may include a vinyl group-containing compound (also referred to as a "vinyl monomer"; however, this does not include a monomer corresponding to a (meth) acrylate monomer hereinafter), and may include a (meth) acrylate monomer having a (meth) acryloyl group. The free-radically polymerizable non-urethane monomers may further include a vinyl-containing compound and a (meth) acrylate monomer.

The vinyl group-containing compound may comprise at least one compound selected from the group consisting of a vinyl ester compound and a vinyl amide compound. Specifically, the radical polymerizable non-urethane monomer may include at least one vinyl group-containing compound selected from a vinyl ester compound and a vinyl amide compound. The number of vinyl groups in the vinyl group-containing compound may be 1, or may be 2 or more.

Examples of the vinyl group-containing compound include vinyl amide compounds (vinyl group-containing lactams) such as N-vinylpyrrolidone and N-vinylcaprolactam, and vinylimidazole and vinylpyridine. From the viewpoint of further increasing the curing speed, the vinyl group-containing compound may be a vinyl amide compound. From the same point of view, the vinylamide compound may be N-vinylcaprolactam.

The content of the vinyl-containing compound in the radiation curable resin composition may be 3 to 20 mass% or 5 to 12 mass% with respect to 100 mass% of the total amount of the radiation curable resin composition.

The radical polymerizable non-urethane monomer may include a monofunctional (meth) acrylate monomer having one (meth) acryloyl group and a multifunctional (meth) acrylate monomer having two or more (meth) acryloyl groups as the (meth) acrylate monomer.

Examples of the monofunctional (meth) acrylate monomer include alicyclic structure-containing (meth) acrylates such as isobornyl (meth) acrylate, bornyl (meth) acrylate, tricyclodecyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and cyclohexyl (meth) acrylate, as well as benzyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, and acryloylmorpholine. Additional examples include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxy ethylene glycol (meth) acrylate, ethoxyethyl (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, and methoxy polypropylene glycol (meth) acrylate. The aforementioned hydroxyl group-containing (meth) acrylate may also be used as the monofunctional (meth) acrylate monomer.

The content of the monofunctional (meth) acrylate monomer in the radiation curable resin composition may be 3 to 30 mass% or 8 to 15 mass% with respect to 100 mass% as the total radiation curable resin composition.

The free-radically polymerizable non-urethane monomers may also include multifunctional (meth) acrylate monomers. This will further increase the crosslink density in the cured layer and thus allow to even further increase the mechanical strength of the cured layer.

Examples of polyfunctional (meth) acrylate monomers include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane trioxethyl (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, di (meth) acrylates of adducts of diols of bisphenol A with ethylene oxide or propylene oxide, Di (meth) acrylates of adducts of diols of hydrogenated bisphenol A with ethylene oxide or propylene oxide (di) acrylates, epoxy (meth) acrylates obtained by adding (meth) acrylates to bisphenol A diglycidyl ether or triethylene glycol divinyl ether, and the like. Examples of commercial products include yuplimer UV SA1002 and SA2007 (both produced by Mitsubishi Chemical corp.); VISCOAT 700(Osaka Organic Chemical Industry, Ltd.); KAYARAD R-604, DPCA-20, -30, -60, -120, HX-620, D-310 and D-330 (all provided by Nippon Kayaku Co., Ltd.); and ARONIX M-210, M-215, M-315 and M-325 (all produced by ToaGosei Co., Ltd.).

The content phase of the polyfunctional (meth) acrylate monomer in the radiation curable resin composition is 2 mass% or less, 1.5 mass% or less, or 1.0 mass% or less and more than 0 mass% with respect to 100 mass% of the total radiation curable resin composition. .

The radiation curable resin composition may include a free radically polymerizable alkoxysilane as the free radically polymerizable non-urethane monomer. The radical polymerizable alkoxysilane may be an alkoxysilane having an ethylenically unsaturated group, or may be an alkoxysilane having a (meth) acryloyl group. Trimethoxysilylpropyl (meth) acrylate is an example of a free-radically polymerizable alkoxysilane.

The content of the radical polymerizable alkoxysilane in the radiation curable resin composition may be more than 0 mass% and 0.5 mass% or less, or 0.10 mass% or more and 0.30 mass% or less.

The molar ratio of the alkoxysilyl group-containing urethane oligomer to the radical polymerizable alkoxysilane may be 0.1/1 to 10/1, 0.5/1 to 7/1, or 0.7/1 to 5/1.

The radiation curable resin composition may further contain a non-radical polymerizable alkoxysilane (an alkoxysilane other than the above-mentioned radical polymerizable alkoxysilane). Tetraethoxysilane is an example of an alkoxysilane.

The content of the alkoxysilane in the radiation curable resin composition may be 0.01 to 2 mass%, 0.1 to 1.5 mass%, or 0.5 to 1.5 mass%, from the viewpoint of maintaining the adhesive force between the cover and the glass. The total content of the alkoxysilane and the radical polymerizable alkoxysilane in the radiation curable resin composition may be within the above range.

The ratio of the total moles of alkoxysilyl group-containing urethane oligomer and free radically polymerizable alkoxysilane to the moles of non-free radically polymerizable alkoxysilane may be 0.05/1 to 4/1, 0.1/1 to 3/1, 0.2/1 to 2/1, or 0.3/1 to 1.5/1.

The ratio of moles of alkoxysilane group-containing urethane oligomer to moles of non-radically polymerizable alkoxysilane may be 0.01/1 to 4/1, 0.05/1 to 3/1, 0.1/1 to 2/1, or 0.1/1 to 1.5/1.

The ratio of moles of free radically polymerizable alkoxysilane to moles of non-free radically polymerizable alkoxysilane can be from 0.01/1 to 3/1, from 0.05/1 to 2/1, from 0.1/1 to 1.5/1, or from 0.15/1 to 1/1.

The radiation curable grease composition includes a polymerization initiator. The polymerization initiator used may be a polymerization initiator generally used as a photopolymerization initiator. Examples of the polymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-dimethoxy-2-phenylacetophenone, anthrone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4 '-dimethoxybenzophenone, 4' -diaminobenzophenone, michelson ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholino Propane-1-one, 2,4, 6-trimethylbenzoyl diphenylphosphine oxide and bis- (2, 6-dimethoxybenzoyl) -2,4, 4-trimethylpentylphosphine oxide; IRGACURE184, 369, 651, 500, 907, CGI1700, CGI1750, CGI1850, CG24-61, DAROCUR1116 and 1173 (all provided by Ciba Specialty Chemicals Co., Ltd.); LUCIRIN TPO (BASF); and UBECRYL P36 (supplied by UCB). Examples of the photosensitizer include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate and isoamyl 4-dimethylaminobenzoate; UBECRYL P102, 103, 104, and 105 (all provided by UCB).

The content of the polymerization initiator in the radiation curable resin composition may be 0.1 to 10 mass% or 0.3 to 7 mass% with respect to 100 mass% as the total radiation curable resin composition.

The radiation curable resin composition may further comprise additives other than the above components. Irganox 245 is an example of such an additive.

In the radiation curable resin composition, in which the urethane oligomer and/or the radical polymerizable non-urethane monomer contains a (meth) acryloyl group containing compound (for example, the aforementioned urethane (meth) acrylate oligomer or (meth) acrylate monomer) and the radical polymerizable non-urethane monomer contains a vinyl group containing compound (vinyl monomer), the ratio of the number of moles of the (meth) acryloyl group containing compound to the number of moles of the vinyl group containing compound may be 1/1 to 10/1, 1/1 to 5/1, 1/1 to 3/1, 1/1 to 2/1, or 1/1 to 1.5/1.

In the radiation curable resin composition in which the urethane oligomer and the radical polymerizable non-urethane monomer include an ethylenically unsaturated group, a ratio of a number of moles of the monofunctional compound having one ethylenically unsaturated group to a number of moles of the polyfunctional compound having two or more ethylenically unsaturated groups may be 2/1 to 100/1, 5/1 to 75/1, 10/1 to 50/1, or 15/1 to 30/1.

In the radiation curable resin composition in which the urethane oligomer or the radical polymerizable non-urethane monomer includes a monofunctional (meth) acrylate (a (meth) acryloyl group containing compound having one (meth) acryloyl group) and a polyfunctional (meth) acrylate (a (meth) acryloyl group containing compound having two or more (meth) acryloyl groups), a ratio of the number of moles of the monofunctional (meth) acrylate in the radiation curable resin composition to the number of moles of the polyfunctional (meth) acrylate in the radiation curable resin composition may be 1/1 to 75/1, 2/1 to 50/1, or 5/1 to 25/1.

The radiation curable resin composition may be in the form of a liquid. Thus, the radiation curable resin composition particles may be in the form of a liquid radiation curable resin composition.

The radiation curable grease composition may also have oligomers, polymers or other additives added as needed.

The viscosity of the radiation curable resin composition at 25 ℃ may be 0.1 to 10Pa · s or 1 to 8Pa · s from the viewpoint of workability and coatability. The viscosity of the radiation curable resin composition was determined by the method described in the examples below.

1J/cm for curing conditions²The cured film of the radiation curable resin composition of (4) may have a Young's modulus at 25 ℃ of 0.8MPa or less. The Young's modulus may be 0.5MPa or less or 0.4MPa or less, and may be 0.1MPa to 0.8MPa, 0.1MPa to 0.5MPa or 0.1MPa to 0.4 MPa. Specific measurement conditions of young's modulus are described in the following examples.

In the radiation curable resin composition of the present embodiment, the curing speed S defined by the following formula (1) is 15% or more.

Formula (1): s (%) ═ Y₂₀/Y₁₀₀₀×100

[ in the formula, Y₁₀₀₀And Y₂₀Young's modulus at 23 ℃ of a cured film of a radiation curable resin composition, Y₁₀₀₀And Y₂₀Respectively at a curing condition of 1J/cm²And 20mJ/cm²。]

The curing speed S may be 50% or higher, 70% or higher, 80% or higher or 81% or higher. The specific measurement conditions of the curing speed S are as described in the following examples.

The cured radiation curable resin composition of the embodiments has excellent flexibility, as well as excellent mechanical strength. The cured radiation curable resin composition may have a breaking strength of 0.5MPa or more, 0.6MPa or more or 0.7MPa or more, and 10MPa or less or 5MPa or less. The elongation at break of the cured radiation curable resin composition may be 130% to 250% or 180% to 240%. The breaking strength and breaking elongation of the cured layer were both measured under the conditions described in the following examples.

[ examples ]

The present invention will now be explained in more detail by means of experimental examples, which are not to be construed as limiting the invention.

Example 1: preparation of radiation curable resin composition

In a reactor equipped with a stirrer, 70.00g of polypropylene glycol having a number average molecular weight of 3000, 6.00g of 2-4-tolylene diisocyanate and 0.019g of 2, 6-di-t-butyl-p-cresol were charged, and the temperature was raised to a liquid temperature of 25 ℃ while stirring. After addition of 0.032g of dibutyltin dilaurate, the liquid temperature was gradually raised to 60 ℃ over 30 minutes while stirring. The mixture was then stirred for 60 minutes, and after the residual isocyanate group concentration had dropped to below 1.18 mass% (ratio relative to the amount fed), 0.19g of γ -mercaptopropyltrimethoxysilane, 1.34g of 2-hydroxyethyl acrylate and 0.032g of dibutyltin dilaurate were added and reacted at a liquid temperature of 60 ℃ for 90 minutes. After the residual isocyanate group concentration was less than 0.37% by mass (ratio to the amount of the fed material), 1.27g of 2-ethylhexanol was added and the reaction was carried out for 60 minutes. When the residual isocyanate group concentration falls below 0.05 mass%, the reaction is considered to be completed. The obtained urethane oligomer is a mixture mainly composed of urethane oligomers represented by the following formulae (I) to (III).

HEA-TDI-(PPG3000-TDI)_2.1-HEA (I)

HEA-TDI-(PPG3000-TDI)_2.1-EH (II)

HEA-TDI-(PPG3000-TDI)_2.1-Sil (III)

[ in the formula, PPG3000 is a structural unit derived from polypropylene glycol having a number average molecular weight of 3000, TDI is a structural unit derived from 2, 4-tolylene diisocyanate, HEA is a structural unit derived from 2-hydroxyethyl acrylate, Sil is a structural unit derived from gamma-mercaptopropyltrimethoxysilane, EH is a structural unit derived from 2-ethyl-1-hexanol, and the bonding positions "-" are urethane bonds. ]

The aliphatic alcohol (2-ethyl-1-hexanol) content of the isocyanate reactive compounds (gamma-mercaptopropyltrimethoxysilane, 2-hydroxyethyl acrylate and 2-ethyl-1-hexanol) was 24 mol% or more.

The obtained urethane oligomer was used to prepare a liquid curable resin composition of example 1 having a composition shown in table 1, and physical property values were evaluated by the following methods.

Example 2: preparation of radiation curable resin composition

The liquid radiation curable resin composition of example 2 was prepared in the same manner as in example 1, except that methanol was used instead of 2-ethylhexanol and the composition was changed as shown in table 1. The urethane oligomer in the radiation curable resin composition of example 2 is a mixture mainly composed of urethane oligomers represented by the formulae (I) and (III) and the following formula (IV).

HEA-TDI-(PPG3000-TDI)_2.1-Me (IV)

[ in the formula, PPG3000, TDI and HEA have the same definitions as above, and Me is a structural unit derived from methanol. ]

[ evaluation method ]

(1) Viscosity:

the 25 ℃ viscosities of the compositions obtained in the examples and comparative examples were measured using a B8H-BII viscometer (product of Tokimec, Inc.).

(2) Young's modulus:

after the compositions obtained in examples and comparative examples were cured, young's modulus was measured. The liquid curable resin composition was coated on a glass plate with a thickness of 354 μm using a coating bar, and the coating was carried out by heating in air at 1J/cm²Ultraviolet rays of energy of (1) are irradiated to cure, thereby obtaining a test film. Sample strips were prepared from the cured film such that the extended portions had a width of 6mm and a length of 25 mm. A tensile test was conducted in accordance with JIS K7127 using an AGS-1KND tensile tester (product of Shimadzu Corp.) under conditions of a temperature of 25 ℃ and a humidity of 50%. ByYoung's modulus was calculated from tensile strength at a tensile rate of 1mm/min and 2.5% strain.

(3) Curing speed:

the curing speed of the compositions obtained in examples and comparative examples was measured. The liquid curable resin composition was coated on a glass plate using a coating rod having a thickness of 354 μm by passing it through a vacuum at 20mJ/cm in air²And 1J/cm²Ultraviolet irradiation of energy of (1) to cure, thereby obtaining two kinds of test films. Sample strips were prepared from both types of cured films such that their extensions each had a width of 6mm and a length of 25 mm. A tensile test was carried out in accordance with JIS K7127 using an AGS-1KND tensile tester (product of Shimadzu Corp.) having a temperature of 23 ℃ and a humidity of 50%. Young's modulus was calculated from tensile strength at a tensile rate of 1mm/min and 2.5% strain. Calculated at 20mJ/cm by the following formula (1)²Young's modulus of cured test films to 1J/cm²The cured test films were evaluated for the ratio of Young' S moduli, and the curing speed S of the composition.

Formula (1): s (%) ═ Y₂₀/Y₁₀₀₀×100

[ in the formula, Y₁₀₀₀And Y₂₀Young's modulus at 23 ℃ of a cured film of a radiation curable resin composition, Y₁₀₀₀And Y₂₀Respectively at a curing condition of 1J/cm²And 20mJ/cm²。]

(4) Breaking strength and elongation at break:

the liquid curable resin composition was coated on a glass plate with a thickness of 354 μm using a coating bar, and the coating was carried out by heating in air at 1J/cm²Ultraviolet rays of energy of (1) are irradiated to cure, thereby obtaining a test film. The breaking strength and breaking elongation of the test piece were measured using a tensile tester (AGS-50G of Shimadzu corp.) under the following measurement conditions.

Stretching rate: 50mm/min

Gauge length (measurement distance): 25mm

Measuring the temperature: 23 deg.C

Relative humidity: 50 percent of

(5) Glass adhesion:

for the radiation curable resin compositions obtained in the examples, the glass adhesion was measured. The liquid curable resin composition was coated on a glass plate with a thickness of 354 μm using a coating bar and cured by ultraviolet irradiation at an energy of 1J/cm 2 in air to obtain a test film. Sample strips were prepared from the cured film such that the extended portions had a width of 10mm and a length of 50 mm. After being left at a temperature of 23 ℃ and a humidity of 50% for 7 days, a glass adhesion test was performed under the same temperature and humidity conditions using an AGS-1KND tensile tester (product of Shimadzu Corp.). The glass adhesion was determined from the tensile strength after 30 seconds with a drawing speed of 50 mm/min.

(6) Gel fraction:

the liquid curable resin composition was coated on a glass plate with a thickness of 354 μm using a coating bar, and the coating was carried out by heating in air at 1J/cm²Ultraviolet rays of energy of (1) are irradiated to cure, thereby obtaining a test film. After curing, the sheet was left to stand in a thermostat at a temperature of 23 ℃ and a humidity of 50% for 24 hours. Then, 1.5g of the cured layer portion was cut out and inserted into a cylindrical filter paper, and extracted with MEK (methyl ethyl ketone) at a temperature of 80 ℃ for 12 hours with a Soxhlet extractor. After extraction, the sample was taken out together with the filter paper and vacuum dried at a temperature of 60 ℃ and a pressure of 1.34kPa or less for 6 hours. The sample was removed from the filter paper and its weight was measured. The gel fraction was calculated by the following formula.

Gel fraction (%) ═ W1/W0X 100

[ in the formula, W0 is the weight of the sample before extraction, and W1 is the weight of the sample after extraction. ]

Table 1 shows the glass transition temperature (Tg) values (curing conditions: 1.0J/cm) of the cured radiation curable resin compositions of examples 1 and 2²And a thickness of 200 μm).

TABLE 1