JP6862776B2 - Curable resin composition, cured product and resin foam produced by using the curable resin composition - Google Patents

Description

The present invention relates to a curable resin composition and a cured product and a resin foam produced by using the resin composition.

The resin foam is lightweight and has excellent moldability, and is used in a wide range of applications mainly as a cushioning material, a cushioning material, a heat insulating material, and a shock absorbing material. Among them, a foam formed by using a thermoplastic resin such as a styrene-based elastomer, an olefin-based elastomer, or a polyurethane-based elastomer is molded and processed by extrusion molding, injection molding, or the like, and is industrially useful. However, there are problems that the thermoplastic resin easily flows by heating, the resistance to chemicals such as an organic solvent may be insufficient, and for example, when an adhesive or the like is used, deformation or chipping is likely to occur.

On the other hand, a method has been proposed in which a foaming agent is added to a curable resin and the resin is foamed at the same time as curing to obtain a resin foam. For example, a polyurethane foam obtained by curing and foaming a resin raw material containing a polyol and an isocyanate by heating is known (see, for example, Patent Document 1). Polyurethane foam has excellent moldability and processability, and is used as a sole material for sports shoes, a building material, an interior material for automobiles, and the like.

As a resin foam that does not use isocyanate, for example, an acrylic resin foam obtained by using (meth) acrylate as a raw material is known (see, for example, Patent Document 2). In the case of an acrylic resin foam, a hard foam can be easily obtained by active light and / or heating.

Japanese Unexamined Patent Publication No. 2011-213924 Japanese Unexamined Patent Publication No. 2006-335962

Polyurethane foams use isocyanates that are concerned about toxicity and environmental pollution, so their applications can be limited, and the amount of heat generated by the reaction between polyols and isocyanates is large, so defects tend to occur in polyurethane foams. There is a problem such as being. Further, the acrylic resin foam produced by using (meth) acrylate is brittle and is not always sufficient in terms of shock absorption.

A main object of the present invention is to provide a resin foam that is lightweight and has excellent shock absorption.

As a result of diligent studies, the present inventors have obtained by curing and foaming a curable resin composition containing a polymerizable compound having an ethylenically unsaturated group, a radical initiator, an oil gelling agent, and a foaming agent. It has been found that the resin foam is lightweight and has excellent impact resistance.

That is, one aspect of the present invention relates to the following.
[1] (A) A polymerizable compound having an ethylenically unsaturated group,
(B) Radical initiator,
Contains (C) oil gelling agent and (D) foaming agent,
A curable resin composition comprising (A) a polydiene compound having a polydiene chain of at least one of (A1) a polyisoprene chain and a polybutadiene chain.
[2] The curable resin composition according to [1], wherein the (D) foaming agent contains at least one of a pyrolysis type foaming agent and a heat expansion type foaming agent.
[3] The curable resin composition according to [1] or [2], which further contains (E) a plasticizer.
[4] The content of the foaming agent (D) is 0.1 to 30% by mass based on the amount of the polymerizable compound or the total amount of the polymerizable compound and the plasticizer, [1] to [1] to [ 3] The curable resin composition according to any one of.
[5] The content of the (C) oil gelling agent is 0.1 to 30% by mass based on the amount of the polymerizable compound or the total amount of the polymerizable compound and the plasticizer, [1] to The curable resin composition according to any one of [4].
[6] The (A) polymerizable compound further contains a low molecular weight (meth) acryloyl compound having a (A2) (meth) acryloyl group and a weight average molecular weight of less than 1000, and the weight average of the (A1) polydiene compound. The curable resin composition according to any one of [1] to [5], which has a molecular weight of 1000 or more.
[7] (C) The oil gelling agent contains at least one compound selected from the group consisting of hydroxystearic acid, hydroxystearic acid amide, and lauroyl-L-glutamic acid-α, γ-dibutylamide [1]. The curable resin composition according to any one of [6].
[8] The curable resin composition according to any one of [1] to [7], wherein the radical initiator is a photoradical polymerization initiator.
[9] A cured product of the curable resin composition according to any one of [1] to [8].
[10] A resin foam containing the cured product according to [9] and in which the cured product is foamed.

The resin foam produced by using the curable resin composition according to one aspect of the present invention can be lightweight and have excellent impact resistance.

It is a schematic diagram which shows the falling ball impact test apparatus.

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

The curable resin composition according to one embodiment includes (A) a polymerizable compound having at least one ethylenically unsaturated group in the molecule, (B) a radical initiator, (C) an oil gelling agent, and ( D) Contains a foaming agent. The curable composition is cured by heating and / or irradiation with active light, and further foams by heating. Hereinafter, (A) the polymerizable compound is referred to as "(A) component", (B) the radical initiator is referred to as "(B) component", (C) the oil gelling agent is referred to as "(C) component", and (D) the foaming agent is used. Also referred to as a "(D)" component.

(A) Polymerizable compound The component (A) is not particularly limited as long as it is a compound having one or more ethylenically unsaturated groups in the molecule. The ethylenically unsaturated group is preferably a (meth) acryloyl group.

Here, the "(meth) acryloyl group" means an "acryloyl group" and a corresponding "methacryloyl group". A compound having a "(meth) acryloyloxy group" is also referred to as a "(meth) acrylate". "(Meta) acrylate" means one or both of "acrylate" and its corresponding "methacrylate".

The component (A) preferably contains a polydiene compound having at least one of the polyisoprene chain and the polybutadiene chain (A1) from the viewpoint of shock absorption and strength of the resin foam.

The weight average molecular weight of the polydiene compound is preferably 1000 or more and 50,000 or less. When the weight average molecular weight is 1000 or more, the strength of the cured product tends to be better. Further, when the weight average molecular weight is 50,000 or less, the viscosity tends to be maintained so that it can be easily handled, and the curable resin composition tends to be easily blended and molded. From such a viewpoint, the weight average molecular weight of the polydiene compound is more preferably 1500 or more and 40,000 or less, and further preferably 2000 or more and 30,000 or less. In the present specification, the weight average molecular weight means a value determined by measuring by gel permeation chromatography (GPC) and converting using a calibration curve of standard polystyrene. The weight average molecular weight (Mw) is defined by the following formula. Here, M _i is the molecular weight, and N _i is the number of moles of the molecule having the molecular weight M _i.
Mw = Σ (N _i M _i ² ) / _{Σ N i} M _i

The polydiene compound may have an ethylenically unsaturated group in the side chain of the polydiene chain or as a terminal group of the polydiene chain. Examples of the polydiene compound having an ethylenically unsaturated group include polyisoprene (meth) acrylate having a (meth) acryloyl group, polybutadiene (meth) acrylate and the like.

The polyisoprene (meth) acrylate is, for example, a compound represented by the following formula (1).

In formula (1), a represents a number of 50 to 1000, b represents a number of 1 to 5, and R ¹¹ represents a hydrogen atom or a methyl group. From the viewpoint of the elasticity of the cured product and the viscosity of the curable resin composition, a is preferably 100 to 800, more preferably 150 to 700, and further preferably 200 to 600. From the viewpoint of reactivity and storage stability of the curable resin composition, b is preferably 1.5 to 4.0, more preferably 2.0 to 3.5, and even more preferably 2.0. ~ 3.0.

Examples of commercially available products of the polyisoprene (meth) acrylate represented by the formula (1) include Claprene UC-102 and Claplen UC-203 (both manufactured by Kuraray Co., Ltd., Claprene is a registered trademark).

The polybutadiene (meth) acrylate is, for example, a compound represented by the following formula (2) or (3).

In formula (2), c represents a number of 5 to 1000, d represents a number of 5 to 1000, and R ^{21 and R 22} each independently represent a hydrogen atom or a methyl group. R ²¹ and R ²² may be the same or different. From the viewpoint of the viscosity and curability of the curable resin composition, c is preferably 10 to 800, more preferably 30 to 700, and further preferably 50 to 600. From the viewpoint of the viscosity and curability of the curable resin composition, d is preferably 10 to 800, more preferably 30 to 700, and further preferably 50 to 600.

A part or all of the ethylenically unsaturated group of the repeating structural unit in the formula (2) may be reduced by hydrogen to form a saturated bond. Increasing the proportion of saturated bonds in the polydiene chain tends to improve the stability of the curable resin composition.

Examples of commercially available products of the polybutadiene (meth) acrylate represented by the formula (2) include BAC-45 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) and the like.

In formula (3), e represents a number of 5 to 1000, f represents a number of 5 to 1000, and R ³¹ and R ³² each independently represent a hydrogen atom or a methyl group. R ³¹ and R ³² may be the same or different. e is preferably 10 to 750, more preferably 15 to 700, still more preferably 20 to 500, from the viewpoint of the viscosity and curability of the curable resin composition. From the viewpoint of the viscosity and curability of the curable resin composition, f is preferably 10 to 750, more preferably 15 to 700, and even more preferably 20 to 500.

A part or all of the ethylenically unsaturated group of the repeating structural unit in the formula (3) may be reduced by hydrogen to form a saturated bond. Increasing the proportion of saturated bonds in the polydiene chain tends to improve the stability of the curable resin composition.

Examples of commercially available products of the polybutadiene (meth) acrylate represented by the formula (3) include TEAI-1000 (manufactured by Nippon Soda Corporation). Moreover, as a commercial product of polybutadiene (meth) acrylate (hydrogenated polybutadiene (meth) acrylate) containing a saturated bond formed by hydrogen reduction, TE-2000 (manufactured by Nippon Soda Co., Ltd.) and the like can be mentioned.

The content of the polydiene compound is preferably 10 to 99% by mass with respect to the total amount of the curable resin composition. When the content of the polydiene compound is 10% by mass or more, the curability of the curable resin composition tends to be improved, and the strength of the cured resin tends to be better. When the content of the polydiene compound is 99% by mass or less, the curing shrinkage rate tends to be small, and the impact absorption of the cured product tends to be higher. From such a viewpoint, the content of the polydiene compound is more preferably 15 to 80% by mass, further preferably 20 to 70% by mass.

(B) Radical Initiator The component (B) is not particularly limited as long as it is a compound that initiates radical polymerization by heating or irradiation with active light. For example, when polymerizing a polymerizable compound having a (meth) acryloyl group as the component (A), a thermal radical polymerization initiator and / or a photoradical polymerization initiator is suitable. In particular, a photoradical polymerization initiator is preferable because it has a high curing rate and can be cured at room temperature.

Examples of the thermal radical polymerization initiator include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and methyl cyclohexanone peroxide; 1,1-bis (t-butylperoxy) cyclohexane, and 1,1-bis (t-). Butyl peroxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1- Peroxyketal such as bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane; hydroperoxide such as p-menthanhydroperoxide; α, α'-bis (t-butylperoxy) diisopropylbenzene , Dialkyl peroxides such as dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide; diacyl peroxides such as octanoyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide; bis ( 4-t-Butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethylperoxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-3-methoxybutylperoxydicarbonate and other peroxycarbonates; t- Butyl peroxypivalate, t-hexyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethyl) Hexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropylmonocarbonate , T-Butylperoxy-3,5,5-trimethylhexanoate, t-Butylperoxylaurylate, t-Butylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexylmonocarbonate, t-butyl Peroxyesters such as peroxybenzoate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyacetate; 2,2'-azobisisobuty Lonitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2) ′ -Dimethylvaleronitrile) and other azo compounds can be mentioned.

The thermal radical polymerization initiator is preferably a diacyl peroxide, a peroxy ester or an azo compound from the viewpoint of curability, transparency and heat resistance.

Examples of the photoradical polymerization initiator include benzoinketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one; 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropane-. Α-Hydroxyketones such as 1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane-1-one; 2-benzyl-2-dimethylamino-1 Α-Aminoketones such as − (4-morpholinophenyl) -butane-1-one, 1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one; 1-[ (4-Phenylthio) phenyl] -1,2-octadion-2- (benzoyl) oxime and other oxime esters; bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl)- Phenyl oxides such as 2,4,4-trimethylpentylphosphenyl oxide, 2,4,6-trimethylbenzoyldiphenylphosphenyl oxide; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-) Chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) 4,5-diphenyl 2,4,5-Triarylimidazole dimer such as imidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer; benzophenone, N, N, N', N'- Benzophenone compounds such as tetramethyl-4,4'-diaminobenzophenone, N, N, N', N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone; 2-ethylanthraquinone , Phenanthrenquinone, 2-tert-butyl anthraquinone, octamethyl anthraquinone, 1,2-benz anthraquinone, 2,3-benz anthraquinone, 2-phenyl anthraquinone, 2,3-diphenyl anthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone , 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone and other quinone compounds; benzoin methyl ether, benzoin ethyl ether, benzoin phenylate Benzoin ethers such as le; benzoin compounds such as benzoin, methylbenzoin, ethylbenzoin; benzyl compounds such as benzyldimethylketal; aclysines such as 9-phenylaclydin and 1,7-bis (9,9'-acridinylheptane). Compounds; N-phenylglycine; coumarin and the like can be mentioned.

In the 2,4,5-triarylimidazole dimer, the substituents on the aryl groups of the two triarylimidazole sites may give the same and symmetric compounds, or different asymmetric compounds. ..

The photoradical polymerization initiator is preferably α-hydroxyketone and / and phosphine oxide from the viewpoint of curability, transparency and heat resistance. These thermal and photoradical polymerization initiators can be used alone or in combination of two or more. In addition, the photoradical polymerization initiator can be combined with a suitable sensitizer.

(C) Oil gelling agent (C) component is a component capable of gelling a curable resin composition. The component (C) is, for example, a hydroxy fatty acid such as hydroxystearic acid (particularly 12-hydroxystearic acid), a hydroxy fatty acid amide such as a hydroxystearic acid amide (particularly 12-hydroxystearic acid amide), or n-lauroyl-L-glutamic acid. -Α, β-dibutylamide, n-lauroyl-L-glutamic acid-α, γ-dibutylamide, di-p-methylbenzidylene sorbitol glucitol, 1,3: 2,4-bis-O-benzidylene-D- Glucitol, 1,3: 2,4-bis-O- (4-methylbenzylidene) -D-sorbitol, bis (2-ethylhexanoato) hydroxyaluminum, and the following formulas (4), (5), (6). ), (7), (8), (9), (10), (11), (12), (13), (14), (15), (16) or (17) Can include at least one compound selected from the group. One of these may be used alone, or two or more thereof may be used in combination. Among these, 12-hydroxystearic acid, 12-hydroxystearic acid amide, and n-lauroyl-L-glutamic acid-α, γ-dibutylamide are preferable from the viewpoint of compatibility.

式（４）中、ｆは３〜１０の整数であり、ｇは２〜６の整数であり、Ｒ^４は炭素数１〜２０の飽和炭化水素基であり、Ｘは硫黄又は酸素である。

In formula (4), f is an integer of 3 to 10, g is an integer of 2 to 6, R ⁴ is a saturated hydrocarbon group having 1 to 20 carbon atoms, and X is sulfur or oxygen.

式（５）中、Ｒ^５は炭素数１〜２０の飽和炭化水素基であり、Ｙ^５は直接結合又はアリーレン基である。

In formula (5), R ⁵ is a saturated hydrocarbon group having 1 to 20 carbon atoms, and Y ⁵ is a direct bond or an arylene group.

式（６）中、Ｒ^６は炭素数１〜２０の飽和炭化水素基であり、Ｙ^６は直接結合又はアリーレン基である。

In formula (6), R ⁶ is a saturated hydrocarbon group having 1 to 20 carbon atoms, and Y ⁶ is a direct bond or an arylene group.

式（７）中、Ｒ^７は炭素数１〜２０の飽和炭化水素基である。

In formula (7), R ⁷ is a saturated hydrocarbon group having 1 to 20 carbon atoms.

式（８）中、Ｒ^８１及びＲ^８２は、それぞれ独立に、炭素数１〜２０の飽和炭化水素基である。

In formula (8), R ⁸¹ and R ⁸² are each independently saturated hydrocarbon groups having 1 to 20 carbon atoms.

式（９）中、Ｒ^９１及びＲ^９２は、それぞれ独立に、炭素数１〜２０の飽和炭化水素基である。

In formula (9), R ⁹¹ and R ⁹² are each independently saturated hydrocarbon groups having 1 to 20 carbon atoms.

一般式（１０）中、Ｒ^１０は、炭素数１〜２０の飽和炭化水素基である。

In the general formula (10), R ¹⁰ is a saturated hydrocarbon group having 1 to 20 carbon atoms.

式（１１）中、Ｒ^１１１は、炭素数１〜２０の飽和炭化水素基である。

In formula (11), R ¹¹¹ is a saturated hydrocarbon group having 1 to 20 carbon atoms.

式（１２）中、Ｒ^１２１及びＲ^１２２は、それぞれ独立に、炭素数１〜２０の飽和炭化水素基である。

In formula (12), R ¹²¹ and R ¹²² are each independently saturated hydrocarbon groups having 1 to 20 carbon atoms.

式（１３）中、Ｒ^１３１はアリール基である。

In formula (13), R ¹³¹ is an aryl group.

式（１４）中、Ｒ^１４１及びＲ^１４２はそれぞれ独立に、炭素数１〜２０の飽和炭化水素基である。

In formula (14), R ¹⁴¹ and R ¹⁴² are each independently saturated hydrocarbon groups having 1 to 20 carbon atoms.

式（１５）中、Ｒ^１５１、Ｒ^１５２及びＲ^１５３はそれぞれ独立に、炭素数１〜２０の飽和炭化水素基である。

In formula (15), R ¹⁵¹ , R ¹⁵² and R ¹⁵³ are each independently saturated hydrocarbon groups having 1 to 20 carbon atoms.

式（１６）中、Ｒ^１６１は水素原子又は炭素数１〜２０の飽和炭化水素基であり、Ｒ^１６２は２価の有機基（例えば、炭素数１〜２０の直鎖型、分岐型、又は環状の２価の炭化水素基）であり、Ｒ^１６３は炭素数１〜２０の飽和炭化水素基である。

In formula (16), ^R161 is a hydrogen atom or a saturated hydrocarbon group having 1 to 20 carbon atoms, and ^R162 is a divalent organic group (for example, a linear type, a branched type or a branched type having 1 to 20 carbon atoms). cyclic divalent hydrocarbon ^{group), R 163} is a saturated hydrocarbon group having 1 to 20 carbon atoms.

In formula (17), R ¹⁷¹ is a hydrogen atom or a saturated hydrocarbon group having 1 to 20 carbon atoms, and R ¹⁷² is a divalent organic group (for example, a linear type, a branched type or a branched type having 1 to 20 carbon atoms). cyclic divalent hydrocarbon ^{group), R 173} is a saturated hydrocarbon group having 1 to 20 carbon atoms.

The content of the oil gelling agent is 0, based on the amount of the polymerizable compound in the curable resin composition or, when the curable resin composition contains a plasticizer, the total amount of the polymerizable compound and the plasticizer. It is preferably 1% by mass or more and 30% by mass or less. When the content of the oil gelling agent is 0.1% by mass or more, the resin is easily incorporated into the matrix formed by the oil gelling agent, and when it is 30% by mass or less, the oil gelling agent may aggregate and be released. It tends to decrease. From such a viewpoint, the content of the oil gelling agent is preferably 0.5 to 25% by mass, more preferably 1 to 20% by mass. When the curable resin composition does not contain a plasticizer, the content of the oil gelling agent can be adjusted based on the amount of the polymerizable compound.

(D) Foaming Agent The foaming agent of the component (D) is not particularly limited as long as it can foam the resin composition by heating or the like. The curable resin composition containing a foaming agent can be a foamable resin composition. For example, the foaming agent can be a pyrolytic foaming agent, a volatile foaming agent, a hollow particle foaming agent, an inorganic foaming agent, a thermal expansion foaming agent, or a combination thereof. From the viewpoint of controlling the foamability, the foaming agent is preferably a pyrolysis type foaming agent, a heat expansion type foaming agent or a combination thereof, and from the viewpoint of the stability of the curable resin composition and the strength of the resin after foaming. Therefore, it is more preferable to use a heat-expandable foaming agent.

The heat-decomposable foaming agent includes, for example, azo compounds such as azodicarboxylic amide, azobisisobutyronitrile, azobishexahydrobenzonitrile, and azobisformamide, hydrazodicarboxylic amide, benzenesulfonyl hydrazide, and p-toluenesulfonyl hydrazide. , P, p'-oxybis (benzenesulfonyl hydrazide) and other hydrazine compounds, N, N'-dinitrosopentamethylenetetramine, N, N'-dinitroso-N, N'-dimethylterephthalamide and other nitroso compounds. It can be at least one organic heat-decomposable foaming agent of choice.

Commercially available thermal decomposition foaming agents include, for example, azo-based products such as Vinihole series (manufactured by Eiwa Kasei Kogyo Co., Ltd.), Uniform AZ (manufactured by Otsuka Chemical Co., Ltd.), and Cellmic C series (manufactured by Sankyo Kasei Co., Ltd.). Foaming agents, hydrazine-based foaming agents such as Neo Cerbon series (manufactured by Eiwa Kasei Kogyo Co., Ltd., Neo Cerbon is a registered trademark), Selmic S series, Selmic 142 (all manufactured by Sankyo Kasei Co., Ltd.), Cellular series (Eiwa Kasei Kogyo Co., Ltd.) Nitroso-based foaming agents such as Selmic A (manufactured by Sankyo Kasei Co., Ltd.) can be obtained.

The curable resin composition may contain a foaming aid such as urea, zinc stearate, calcium stearate, calcium carbonate, and zinc oxide for the purpose of lowering the decomposition temperature of the pyrolytic foaming agent. Zinc stearate and zinc oxide are preferable because the decomposition temperature of the pyrolysis type foaming agent can be easily adjusted to the processing temperature range of foam molding. The content of the foaming aid is not particularly limited, but is preferably 1 to 50 parts by mass with respect to 100 parts by weight of the pyrolysis type foaming agent.

The heat-expandable foaming agent generally has a shell containing a thermoplastic resin (also referred to as a shell), and a low boiling point hydrocarbon or the like contained in the shell, which is liquid at room temperature. As commercially available thermal expansion foaming agents, for example, Matsumoto Microsphere (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.), Expandel (manufactured by Nippon Ferrite Co., Ltd.), and Advancel (manufactured by Sekisui Chemical Co., Ltd.) can be obtained. ..

The volume average particle size of the heat-expandable foaming agent before expansion is not particularly limited, but is preferably 10 to 200 μm. If the volume average particle size before expansion is less than 10 μm, the bubbles in the resin foam tend to be too small, and the effect of weight reduction tends to be small. When the volume average particle size exceeds 200 μm, the bubbles of the resin foam become too large, and the strength tends to be insufficient. From the above viewpoint, the volume average particle size of the thermal expansion type foaming agent is more preferably 15 to 175 μm, still more preferably 20 to 150 μm.

The foaming agent may be used alone or in combination of two or more. A pyrolysis type foaming agent and a heat expansion type foaming agent may be combined.

The content of the foaming agent is 0.5 with respect to the amount of the polymerizable compound in the curable resin composition or, when the curable resin composition contains a plasticizer, the total amount of the polymerizable compound and the plasticizer. ~ 50 parts by mass is preferable. When the content of the foaming agent is 0.5 parts by mass or more, a more remarkable effect can be obtained in terms of weight reduction. When the content of the foaming agent is 50 parts by mass or less, the dispersibility of the foaming agent in the resin is good, so that the pores in the resin foam tend to be uniformly distributed. From this point of view, the content of the foaming agent is more preferably 0.7 to 30 parts by mass, still more preferably 1 to 20 parts by mass. When the curable resin composition does not contain a plasticizer, the content of the foaming agent can be adjusted based on the amount of the polymerizable compound.

(E) Plasticizer The curable resin composition according to the embodiment may further contain a plasticizer (hereinafter, also referred to as component (E)) in addition to the components (A) to (D). The plasticizer can improve the flexibility of the cured product and suppress the destruction of the resin foam.

Plastic agents include, for example, butadiene rubber, isoprene rubber, silicon rubber, styrene butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, urethane rubber, acrylic rubber, chlorosulfonated polyethylene rubber, fluororubber, and hydride nitrile rubber. , Epichlorohydrin rubber liquid; poly-α-olefins such as polybutane, hydrogenated α-olefin oligomers such as hydrogenated polybutene, polyvinyl-based oligomers such as atactic polypropylene; aromatic oligomers such as biphenyl and triphenyl; hydrogenated liquid Hydrogenated polyene-based oligomers such as polybutadiene; Paraffin-based oligomers such as paraffin oil and chloride paraffin oil; Cycloparaffin-based oligomers such as naphthenic oil; Dimethylphthalate, diethylphthalate, dibutylphthalate, di- (2-ethylhexyl) phthalate, di- n-octyl phthalate, diisobutyl phthalate, diheptyl phthalate, diphenyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, di (heptyl, nonyl, undecyl) phthalate, benzyl phthalate, butyl benzyl phthalate, dinonyl phthalate, dicyclohexyl phthalate, etc. Phthalate derivatives of: dimethylisophthalate, di- (2-ethylhexyl) isophthalate, diisooctylisophthalate and other isophthalate derivatives; di- (2-ethylhexyl) tetrahydrophthalate, di-n-octyltetrahydrophthalate, diisodecyltetrahydro Tetrahydrophthalate derivatives such as phthalates; adipic acid derivatives such as di-n-butyl adipate, di (2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate; di- (2-ethylhexyl) azelate, diisooctyl azelate, di Azelaic acid derivatives such as -n-hexyl azelate; sebacic acid derivatives such as di-n-butyl sebacate and di- (2-ethylhexyl) sebacate; di-n-butylmalate, dimethylmalate, diethylmalate, di- (2) Maleic acid derivatives such as -ethylhexyl) malate; fumaric acid derivatives such as di-n-butyl fumalate, di- (2-ethylhexyl) fumalate; tri- (2-ethylhexyl) trimellitate, tri-n-octyl remeritate, Triisodecyl trimethylate, triisooctyl thalate, tri-n-hexi Trimeritic acid derivatives such as rutrimeritate and triisononyl trimerite; pyromellitic acid derivatives such as tetra- (2-ethylhexyl) pyromeritate and tetra-n-octylpyromeritete; triethylcitrate, tri-n-butylcitrate , Citric acid derivatives such as acetyltriethylcitrate, acetyltri- (2-ethylhexyl) citrate; monomethylitaconate, monobutylitaconate, dimethylitaconate, diethylitaconate, dibutylitaconate, di- (2-ethylhexyl) itaconate. Etc. itaconic acid derivatives; oleic acid derivatives such as butyl oleate, glyceryl monooleate, diethylene glycol monooleate; lysinolic acid derivatives such as methyl acetyl ricinolate, butyl acetyl ricinolate, glyceryl monolithinolate, diethylene glycol monolithinolate; n-butyl Steeric acid derivatives such as stearate, glycerin monostearate, diethylene glycol distearate; other fatty acid derivatives such as diethylene glycol monolaurate, diethylene glycol dipelargonate, pentaerythritol fatty acid ester; triethyl phosphate, tributyl phosphate, tri- (2-) Ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, cresyldiphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, phosphate derivatives such as tris (chloroethyl) phosphate; diethylene glycol dibenzoate, dipropylene glycol dibenzoate, tri Glycol derivatives such as ethylene glycol dibenzoate, triethylene glycol di- (2-ethylbutyrate), triethylene glycol di- (2-ethylhexoate), dibutylmethylene bisthioglycolate; glycerol monoacetate, glycerol triacetate, Glycerin derivatives such as glycerol tributylate, epoxidized soybean oil, epoxides such as epoxide hexahydrophthalate diisodecyl, epoxide triglycerides, epoxidized octyl oleate, epoxidized decyl oleate and other epoxy derivatives; Examples thereof include an acrylic copolymer obtained by subjecting the mixture. These compounds may be used alone or in combination of two or more.

The plasticizer may have a functional group such as a hydroxy group, a carboxy group, a thiol group, a thiocarboxy group, a sulfonyl group, an anhydrous carboxy group, an amino group and an amide group. When the plasticizer has these functional groups, it is possible to impart adhesiveness to different materials, heat resistance, and the like to the curable resin composition.

The plasticizer is at least one compound selected from the group consisting of isoprene polymers, butadiene polymers, and copolymers of two or more compounds selected from styrene, isoprene, butadiene, and ethylene, and is ethylenically. Those having no unsaturated group may be included. Here, the butadiene polymer can have a "1,4-structural unit" or a "1,2-structural unit". The "1,4-structural unit" is a repeating unit represented by the following formula (18) or (19), and the "1,2-structural unit" is a repeating unit represented by the following formula (20). It is a unit.

The isoprene polymer is commercially available as, for example, Claprene LIR-10, LIR-30, LIR-50, LIR-700, LIR-403, LIR-410 (all manufactured by Kuraray Co., Ltd., Claplen is a registered trademark). Is. LIR-403 and LIR-410 are isoprene polymers having a functional group.

The butadiene polymer is, for example, RICON130, RICON131 (all manufactured by CRAY VALLEY, polybutadiene mainly containing 1,4-structural unit (content ratio of 1,4-structural unit: 72%), claprene LBR-302, LBR). -305, LBR-307, LBR352 (all manufactured by Kuraray Co., Ltd., Claplen is a registered trademark, (LBR-302, LBR-305, LBR-307 are polybutadienes and LBR-352 whose main structural units are 1,4-structural units). 1,2-Structural unit and 1,4-Structural unit are mixed)), B-1000, B-2000, B-3000 (all manufactured by Nippon Soda Co., Ltd., mainly 1,2-Structural unit). Polybutadiene), butadiene polymers with functional groups G-1000, G-2000, G-3000 (all manufactured by Nippon Soda Co., Ltd., polybutadiene mainly composed of 1,2-structural units) are commercially available. Is.

Copolymers of two or more compounds selected from styrene, isoprene, butadiene and ethylene are, for example, Claprene LIR-310, LIR-390, L-SBR-820, L-SBR-841 (all manufactured by Kuraray Co., Ltd.). , Claprene is a registered trademark, LIR-310 and LIR-390 are styrene-isoprene copolymers, and L-SBR-820 and L-SBR-841 are styrene-butadiene copolymers).

From the viewpoint of volatileness, viscosity, workability, yellowing resistance, compatibility, and heat resistance, the plasticizer may be a butadiene polymer, an isoprene polymer, a poly α-olefin, a hydrogenated α-olefin oligomer, an acrylic copolymer, or the like. It is preferable to include these combinations.

The content of the plasticizer is preferably 1 to 90% by mass, more preferably 5 to 80% by mass, based on the total amount of the curable resin composition, from the viewpoint of adjusting the flexibility of the cured product to an appropriate range. More preferably, it is 10 to 70% by mass.

(A2) Low-Molecular (Meta) Acryloyl Compound The curable resin composition according to one embodiment has one or more (meth) acryloyl groups in the molecule as a polymerizable compound and does not have a polydiene chain. A meta) acryloyl compound (hereinafter, also referred to as a component (A2)) may be further contained. The low molecular weight (meth) acryloyl compound is, for example, at least one of a (meth) acrylate derivative represented by the following formula (21) and a (meth) acrylamide derivative represented by the following formula (22). Is preferable. The weight average molecular weight or molecular weight of the low molecular weight (meth) acryloyl compound may be less than 1000.

式（２１）中、Ｒ^２１１は水素原子又は炭素数１〜２０のアルキル基、環式アルキル基、芳香族含有官能基、又は複素環式官能基を示し、Ｒ^２１２は水素原子又はメチル基を示す。

In formula (21), R ²¹¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, a cyclic alkyl group, an aromatic-containing functional group, or a heterocyclic functional group, and R ²¹² represents a hydrogen atom or a methyl group. Shown.

一般式（２２）中、Ｒ^２２１及びＲ^２２２はそれぞれ独立に水素原子又は炭素数１〜２０のアルキル基を示し、Ｒ^２２３は水素原子又はメチル基を示す。Ｒ^２２１及びＲ^２２２は同じであっても、異なっていてもよい。

In the general formula (22), R ²²¹ and R ²²² each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ²²³ represents a hydrogen atom or a methyl group. R ²²¹ and R ²²² may be the same or different.

Examples of the (meth) acrylate derivative represented by the formula (21) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-butyl (meth) acrylate. Butoxyethyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octylheptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) Acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene Acrylate (meth) acrylates such as glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, mono (2- (meth) acryloyloxyethyl) succinate; cyclopentyl (meth) acrylate, Cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyloxyethyl acrylate, isobornyl (meth) acrylate, Mono (2- (meth) acryloyloxyethyl) tetrahydrophthalate, mono (2- (meth) acryloyloxyethyl) hexahydrophthalate, 1-decahydronaphthalene (meth) acrylate, 2-decahydronaphthalene (meth) acrylate Acrylate-type (meth) acrylates such as benzyl (meth) acrylate, phenyl (meth) acrylate, o-biphenyl (meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, phenoxyethyl (meth). ) Acrylate, p-cumylfe Noxyethyl (meth) acrylate, o-phenylphenoxyethyl (meth) acrylate, 1-naphthoxyethyl (meth) acrylate, 2-naphthoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, phenoxy Polypropylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (1-naphthoxy) propyl Aromatic (meth) acrylates such as (meth) acrylate, 2-hydroxy-3- (2-naphthoxy) propyl (meth) acrylate; 2-tetrahydrofurfuryl (meth) acrylate, N- (meth) acryloyloxyethyl hexa. Examples thereof include heterocyclic (meth) acrylates such as hydrophthalimide and 2- (meth) acryloyloxyethyl-N-carbazole, and modified caprolactones thereof. These compounds may be used alone or in combination of two or more.

Examples of the acrylamide derivative represented by the formula (22) include hydroxyl group-containing (meth) acrylamide such as hydroxyethyl (meth) acrylamide; (meth) acrylamide such as dimethylacrylamide, isopropylacrylamide, dimethylaminopropylacrylamide and hydroxyethylacrylamide. Can be mentioned. These compounds may be used alone or in combination of two or more.

The weight average molecular weight of the low molecular weight (meth) acryloyl compound is preferably 1000 or less. When the weight average molecular weight of the low molecular weight (meth) acryloyl compound is 1000 or less, the viscosity of the curable resin composition tends to decrease and the handleability tends to improve. The lower limit of the weight average molecular weight of the low molecular weight (meth) acryloyl compound is not particularly limited, but may be 50 or more.

The content of the low molecular weight (meth) acryloyl compound in the curable resin composition is cured from the viewpoint of appropriate viscosity of the curable resin composition, and from the viewpoint of adjusting the curing shrinkage rate and the elastic modulus of the cured product. It is preferably 0.1 to 30% by mass, more preferably 0.5 to 25% by mass, still more preferably 1 to 25% by mass, and particularly preferably 3 to 20% by mass, based on the total amount of the sex resin composition. .. When the content of the low molecular weight (meth) acryloyl compound is 0.1% by mass or more, a curable resin composition having an appropriate viscosity can be easily obtained, thereby improving workability at the time of coating. Can be done. Further, the curing shrinkage rate tends to be low, the curability of the curable resin composition in the light-shielding portion tends to be good, and the transparency of the cured product tends to be improved. When the content of the (meth) acryloyl compound is 30% by mass or less, the curing shrinkage rate tends to be appropriately reduced.

Other Additives The curable resin composition according to one embodiment is a so-called additive such as an antioxidant, an antioxidant, an ultraviolet absorber, a visible light absorber, a colorant, a plasticizer, a stabilizer, and a filler. May be included without departing from the gist of the present invention.

As additives, for example, stabilizers such as triphenyl phosphite, 1,4-bis (3-mercaptobutylyloxy) butane, 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3, Thiol compounds such as 5-triazine-2,4,6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate) can be mentioned.

The curable resin composition may be diluted with an organic solvent suitable from the viewpoint of compatibility and viscosity to form a resin varnish. The organic solvent used here is not particularly limited as long as it can dissolve the curable resin composition, and for example, aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, cumene, and p-simene; tetrahydrofuran, Cyclic ethers such as tetrahydropyran, 1,4-dioxane; alcohols such as methanol, ethanol, 1-propanol, isopropanol, butanol, ethylene glycol, propylene glycol; acetone, methyl ethyl ketone, methyl isobutyl ketone, 3-pentanone, cyclopentanone, Ketones such as cyclohexanone and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, normal butyl acetate, isobutyl acetate, methyl lactate, ethyl lactate and γ-butyrolactone; ethylene carbonate, propylene carbonate and the like. Carbonate ester; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol monomethyl Polyhydric alcohol alkyl ethers such as ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, Polyhydric alcohol alkyl ether acetates such as propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate and diethylene glycol monoethyl ether acetate; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone. And so on.

Among these, from the viewpoint of solubility and boiling point, toluene, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, 3-pentanone, cyclohexanone, methyl acetate, ethyl acetate, normal butyl acetate, isobutyl acetate, methyl lactate. , Ethyl lactate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate or N, N-dimethylacetamide are preferable.

The organic solvent can be used alone or in combination of two or more. The solid content concentration (concentration of components other than the organic solvent) in the resin varnish is not particularly limited, but is preferably 10 to 90% by mass. If the solid content concentration of the resin varnish is 10% by mass or more, the solvent tends to be easily removed by drying, and if it is 90% by mass or less, handling tends to be easy.

Hereinafter, the forms of the cured product and the resin foam produced from the curable resin composition according to the present embodiment will be described. The resin foam is a cured product containing bubbles formed by foaming.

The resin foam is produced, for example, by a method including a step of curing the curable resin composition by irradiation or heating with active light and a step of foaming the cured product. The form of the cured product and the resin foam is not particularly limited, and may be, for example, a sheet-like shape, a thread-like shape, a fibrous shape, or another three-dimensional shape.

As a curing method of the curable resin composition, a method of irradiating with active light rays is preferable from the viewpoint of handleability, short tactivity, and energy saving. Examples of the light source of the active light include a light source that effectively emits ultraviolet rays such as a carbon arc lamp, a mercury vapor arc lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, and a xenon lamp. Other light sources include those that effectively radiate visible light, such as photographic flood bulbs and sun lamps. The irradiation amount of the active light is preferably ^{0.01 to 50 J / cm 2.} When the irradiation amount is 0.01 J / cm ² or more, the curing reaction proceeds sufficiently, and a cured product having a desired shape tends to be easily obtained. When the irradiation amount is 50 J or less, the energy is not excessive and the (resin) cured product can be efficiently obtained.

After irradiation with the active light, the curable resin composition may be heated to the extent that the foaming agent does not react. By heating after exposure, the curing reaction is promoted, and the strength of the cured product tends to be improved. The heating temperature at this time is preferably 40 ° C. to 200 ° C., and the heating time is preferably 30 seconds to 1 hour. It is preferable to appropriately adjust the heating temperature and heating time according to the reactivity of the foaming agent and the like.

Next, the desired resin foam can be obtained by heating and foaming the obtained cured product. The heating temperature may be adjusted according to the reaction temperature of the foaming agent, and is preferably 60 to 300 ° C., for example. The heating time may be, for example, 1 to 90 minutes. The curable resin composition may be partially cured in the curing step before foaming, and the resin may be foamed while further curing in the foaming step.

The resin foam produced from the curable resin composition according to one embodiment can be lightweight, shock-absorbent, and highly flexible. Due to the high degree of freedom in design, resin foams are, for example, shock absorbers, shock cushioning materials, pressure dispersants, vibration damping materials, vibration isolating materials, sound absorbing materials, soundproofing materials, sound insulating materials, heat storage materials, heat insulating materials. , Or it can be used as a feel improving member. Feel-improving members include, for example, sports equipment, toys / play equipment, stationery, medical / nursing care, footwear, bedding / bedding, furniture, clothing, various miscellaneous goods, transportation, packaging, and OA equipment. , Home appliances, audio equipment, portable equipment, industrial machinery / equipment, precision equipment electrical / electronic equipment, electrical / electronic parts, robot parts, building materials, flooring. Resin foams are particularly useful for sports applications in terms of design freedom, light weight and flexibility.

Examples of sports applications in which the resin foam according to the present embodiment is useful include impact shock absorbers installed on the fences of ball games, stadiums, etc., landing mats for gymnastics or exercise, floor exercise mats, and gym stretches. Mats for kids, kids mats, mats for bouldering, cushioning materials for high jumps, wet suits, grips or core materials for golf clubs, bats, tennis rackets, etc. Bottom, liner for ski boots / snowboard boots, inner material for golf club heads, protectors for sports (for example, head gear used in martial arts such as rugby and boxing, helmets for baseball or football, elbows for baseball / soccer / martial arts, etc. , Leggers (Singard, etc.), racket guts or grips, balls, rider suits, gloves (soccer keeper gloves, golf, skis, riders), rifle jackets (eg shoulder pads). Among these, it is preferable to use the resin foam for the overlay, insole, shock absorbing member, sole, etc. of sports shoes.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

1. 1. Preparation of Curable Resin Composition The components (A) to (E) were mixed at the blending ratios shown in Table 1. The mixture was heated to 80 ° C. and stirred using a rotation / revolution mixer until uniform to prepare the resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5. The unit of the numerical value for the components (A) to (E) in Table 1 is the mass part.

The details of each component shown in Table 1 are shown below.
(A) Polymerizable compound (A1) Polydiene compound-UC-203M: Isoprene polymer having a methacryloyl group (manufactured by Kuraray Co., Ltd., product name: Claprene UC-203M (Claprene is a registered trademark), weight average molecular weight: 35,000 )
BAC-45: Butadiene polymer having an acryloyl group (manufactured by Osaka Organic Chemical Industry Co., Ltd., product name: BAC-45, terminal acryloyl group-modified 1,2-structural unit butadiene polymer)
(A2) A compound having one or more (meth) acryloyl groups and having a weight average molecular weight of less than 1000. FA-513AS: Tricyclodecanemethyl acrylate (manufactured by Hitachi Kasei Co., Ltd., product name: Funkryl FA-513AS, Funkryl is a registered trademark, molecular weight: 206.3)

(B) Radical initiator I-1173: 2-hydroxy-2-methyl-1-phenyl-propane-1-one (manufactured by BASF, product name: IRGACURE 1173 (IRGACURE is a registered trademark))
-I-TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (manufactured by BASF, product name: IRGACURE TPO (IRGACURE is a registered trademark))

(C) Oil gelling agent, 12-hydroxystearic acid (manufactured by Wako Pure Chemical Industries, Ltd.)

(D) Foaming agent, azodicarbonamide (manufactured by Wako Pure Chemical Industries, Ltd.)
・ EML101 (Advancel EML101, manufactured by Sekisui Chemical Co., Ltd., average particle size: 14 to 20 μm, Advancel is a registered trademark)
・ EM403 (Advancel EM403, manufactured by Sekisui Chemical Co., Ltd., average particle size: 26 to 34 μm, Advancel is a registered trademark)
・ EM501 (Advancel EM501, manufactured by Sekisui Chemical Co., Ltd., average particle size: 22 to 28 μm, Advancel is a registered trademark)

(E) Plasticizer LBR-307 (1,4-butadiene polymer, manufactured by Kuraray Co., Ltd., product name: Claprene LBR-307, Claprene is a registered trademark, weight average molecular weight: 8000)
LIR-410 (isoprene polymer having a carboxy group, manufactured by Kuraray Co., Ltd., product name: Claprene LIR-410, Claprene is a registered trademark, weight average molecular weight: 30,000)

2. Preparation of cured resin product A release PET film (Film Bina DG-50, manufactured by Fujimori Kogyo Co., Ltd.) is placed on a glass plate (thickness 3 mm) and cut out so that an opening of 35 mm x 35 mm is formed on it. A silicone sheet (thickness 5 mm, manufactured by Togawa Rubber Co., Ltd.) was placed on the mold to form a mold. The curable resin composition prepared in "1. Preparation of curable resin composition" is heated to 80 ° C. and poured into this mold, and the release PET film and the glass plate (thickness 3 mm) are placed in this order. A load was applied so that the thickness of the sample was 5 mm, and the sample was cooled to room temperature. Next, both sides were exposed at ^{2500 mJ / cm 2} using an ultraviolet irradiation device (UV-Xe-FL manufactured by Ushio, Inc.). Then, the glass plate and the release PET film were removed, and a sample of the cured resin product was taken out from the mold.

3. 3. Preparation of resin foam (1) (D) When EM403, EM501, and azodicarboxylic are used as the foaming agent (Examples 1, 3, and 4)
The cured resin obtained in "2. Preparation of cured resin" was foamed by heating at 200 ° C. for 30 minutes using an explosion-proof constant temperature bath (manufactured by ESPEC Co., Ltd.) to obtain a resin foam. ..
(2) (D) When EML101 is used as the foaming agent (Examples 2, 5 and 6)
A resin foam was obtained in the same manner as in the method (1) except that the temperature was set to 160 ° C.

4. Evaluation (1) Specific gravity The specific gravity of the foam or cured resin obtained from each resin composition was measured with a digital hydrometer SD-200L (manufactured by ALFA MIRAGE).

(2) Impact Absorption Rate The impact absorption rate of each foam or cured resin was measured using the falling ball impact test device shown in FIG. Sheet-shaped resin foam 1 (or resin curing) as a sample is placed on a laminate in which SUS plate 3a (thickness 1 m) / silicone sheet 5 (thickness 1 mm) / SUS plate 3b (thickness 1 mm) is stacked. An object) (thickness 5 mm) was placed, and a tubular guide 11 was placed in the center of the resin foam 1. A weight 7 (315 g) with an accelerometer 9 (MODEL-1340 manufactured by Showa Sokki Co., Ltd.) was freely dropped toward the resin foam 1 from a height of 400 mm above the guide 11. The peak acceleration (hereinafter, also referred to as “impact acceleration A”) when the weight 7 collided with the resin foam 1 was measured. Further, when the resin foam 1 is not placed on the laminate, the weight 7 (315 g) with the accelerometer 9 attached to the laminate is freely dropped from a height of 400 mm, and the weight 7 collides with the laminate. The peak acceleration (hereinafter, also referred to as "impact acceleration B") was measured. From the impact strengths A and B, the impact absorption rate was calculated by the following formula.
Impact absorption rate (%) = {(Impact acceleration B-Impact acceleration A) / (Impact acceleration B)} x 100

Table 1 shows the measurement results of specific gravity and shock absorption rate. From Table 1, the foams of Examples 1 to 6 have a specific gravity that is about 15 to 50% smaller than that of the cured resin products of Comparative Examples 1 to 5, and have the same impact absorption as the cured resin products of Comparative Examples. It was found to have sex.

The resin foam produced from the curable resin composition of the present invention can be reduced in weight while maintaining shock absorption. As a result, when the resin foam is used as a member used for a portion to which an impact is applied, weight reduction is expected while maintaining impact resistance. Therefore, the resin foam is useful as a shock absorbing material, and is particularly suitable as an underlay, an insole, a shock absorbing member, and a sole member for sports shoes.

1 ... Resin foam, 3a, 3b ... SUS plate, 5 ... Silicone sheet, 7 ... Weight, 9 ... Accelerometer, 11 ... Guide.

Claims (10)

(A) A polymerizable compound having an ethylenically unsaturated group,
(B) Radical initiator,
Contains (C) oil gelling agent and (D) foaming agent,
(A) the polymerizable compound, see containing a polydiene compound having an (A1) at least one of the polydiene chains of polyisoprene chains or polybutadiene chain,
(D) The foaming agent contains a thermal decomposition type foaming agent, a hollow particle type foaming agent, a heat expansion type foaming agent, or a combination thereof, and the thermal decomposition type foaming agent is an azo compound, a hydrazine compound, and a nitroso compound. At least one organic pyrolytic foaming agent selected from compounds,
Curable resin composition. (D) The curable resin composition according to claim 1, wherein the foaming agent contains at least one of a pyrolysis type foaming agent and a heat expansion type foaming agent. (E) The curable resin composition according to claim 1 or 2, further containing a plasticizer. (D) Any of claims 1 to 3, wherein the content of the foaming agent is 0.1 to 30% by mass based on the amount of the polymerizable compound or the total amount of the polymerizable compound and the plasticizer. The curable resin composition according to item 1. (C) Any of claims 1 to 4, wherein the content of the oil gelling agent is 0.1 to 30% by mass based on the amount of the polymerizable compound or the total amount of the polymerizable compound and the plasticizer. The curable resin composition according to item 1. The polymerizable compound further contains a low molecular weight (meth) acryloyl compound having a (A2) (meth) acryloyl group and a weight average molecular weight of less than 1000, and the weight average molecular weight of the (A1) polydiene compound is 1000. The curable resin composition according to any one of claims 1 to 5, which is the above. (C) The oil gelling agent according to claim 1 to 6, wherein the oil gelling agent contains at least one compound selected from the group consisting of hydroxystearic acid, hydroxystearic acid amide, and lauroyl-L-glutamic acid-α, γ-dibutylamide. The curable resin composition according to any one of the items. (B) The curable resin composition according to any one of claims 1 to 7, wherein the radical initiator is a photoradical polymerization initiator. A cured product of the curable resin composition according to any one of claims 1 to 8. A resin foam containing the cured product according to claim 9, wherein the cured product is foamed.

Images