JP2023164301A - Composition for expanded material, expanded material, and production method of expanded material - Google Patents

Abstract

To provide a composition for an expanded material capable of providing an expanded material that keeps an excellent balance between impact resilience and tear strength and high dimensional stability to heat even when saving a weight.SOLUTION: A composition for an expanded material contains a conjugated diene-based copolymer (A) including a conjugated diene monomer unit and a vinyl aromatic monomer unit, and a foaming agent (E). The component (A) has a content of the vinyl aromatic monomer unit of 5-15 mass%. The conjugated diene monomer unit in the component (A) has a hydrogenation rate of 30-100 mass%. The composition for an expanded material has a content of the component (A) of 5-50 pts.mass relative to 100 pts.mass of an expandable polymer containing the component (A).SELECTED DRAWING: None

Description

The present invention relates to a composition for a foam, a foam, and a method for producing a foam.

In recent years, foam materials have been attracting attention from the viewpoint of reducing the weight of resin compositions.
However, simply foaming a resin composition made of a resin or an elastomer reduces its mechanical strength, resulting in problems such as deterioration and sagging during long-term use. Therefore, by making it into a crosslinked foam, it is widely used as a lightweight and high mechanical strength material for automobile-related parts, construction-related parts, various packaging materials, daily necessities, etc.

Ethylene-vinyl acetate copolymer (EVA) is known as a typical cross-linked foam, but because of its high specific gravity and large compression set, it suffers from low weight and poor mechanical strength due to long-term use. It becomes.
One application of crosslinked foams is footwear, such as the soles (mainly midsoles) of sports shoes. With the increasing demand for running in recent years, there is a demand for midsoles that are lighter, have higher resilience, and have higher mechanical strength.

Various studies have been made to address the above-mentioned problems.
For example, Patent Document 1 discloses that a resin composition containing an ethylene/α-olefin copolymer and a styrene copolymer and further containing an organic peroxide, a crosslinking aid, and a foaming agent is crosslinked and foamed. A crosslinked foam is disclosed.
Further, Patent Document 2 discloses a crosslinked foam obtained by crosslinking and foaming a resin composition containing an ethylene/α-olefin copolymer and a styrene block copolymer, to which EVA is added.

International Publication No. 2010/073589 International Publication No. 2005/000958

However, the conventionally disclosed crosslinked foams have a problem in that there is still room for improvement regarding the balance of various physical properties. It is possible to improve impact resilience etc. by using an ethylene copolymer or styrene block copolymer as in Patent Document 1 and Patent Document 2, but there are new problems such as the foam shrinking at high temperatures comparable to those inside a car in summer problems occur.

Therefore, in view of the above-mentioned problems of the prior art, the present invention provides a composition for a foam that can obtain a foam that has an excellent balance of impact resilience and tear strength even when it is lightweight, and has high dimensional stability against heat, and the foam. An object of the present invention is to provide a foam using a composition for use in the present invention.

As a result of extensive research to solve the above problems, the present inventors have found that the above problems can be solved by a foam composition containing a conjugated diene copolymer having a specific structure and a blowing agent. This discovery led to the completion of the present invention.
That is, the present invention is as follows.

[1]
(A) a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit;
(E) A foam composition comprising a foaming agent,
The content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass,
The hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100% by mass,
The content of the component (A) is 5 to 50 parts by mass relative to 100 parts by mass of the foamable polymer containing the component (A) in the foam composition.
Composition for foams.
[2]
(B) an ethylene/polar monomer copolymer;
(D) a crosslinking agent;
A composition for a foam further comprising:
5 to 50 parts by mass of the component (A) and 50 parts by mass of the component (B) to 100 parts by mass of the foamable polymer containing the component (A) and the component (B) in the foam composition. The composition for a foam according to [1] above, containing ~95 parts by mass.
[3]
[1] or [2] above, wherein the amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of the component (A) is 10 to 60% by mass. Composition for foams.
[4]
Any one of [1] to [3] above, wherein the amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of the component (A) is 10 to 50% by mass. 1. The composition for foam according to item 1.
[5]
Any one of [1] to [4] above, wherein the amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of component (A) is 15 to 50% by mass. 1. The composition for foam according to item 1.
[6]
Any one of [1] to [5] above, wherein the amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of the component (A) is 25 to 50% by mass. 1. The composition for foam according to item 1.
[7]
The foam composition according to any one of [1] to [6] above, wherein the component (A) has a peak top molecular weight of 80,000 to 200,000.
[8]
The foam composition according to any one of [1] to [7] above, wherein the component (A) has a peak top molecular weight of 100,000 to 150,000.
[9]
The composition for a foam according to any one of [1] to [8] above, wherein the hydrogenation rate of the conjugated diene monomer unit of the component (A) is 50 to 100% by mass.
[10]
The composition for a foam according to any one of [1] to [9] above, wherein the hydrogenation rate of the conjugated diene monomer unit of the component (A) is 70 to 100% by mass.
[11]
The composition for a foam according to any one of [1] to [10] above, wherein the hydrogenation rate of the conjugated diene monomer unit of the component (A) is 95 to 100% by mass.
[12]
The composition for a foam according to any one of [1] to [11] above, wherein the MFR (230° C., 2.16 kg) of the component (A) is 1.0 to 15 g/10 min.
[13]
The vinyl aromatic monomer of the component (A) is styrene, the conjugated diene monomer is 1,3-butadiene,
The foam composition according to any one of [1] to [12] above, wherein the component (A) has a block structure of styrene block-1,3-butadiene block-styrene block.
[14]
The composition for a foam according to any one of [1] to [13] above, wherein the tan δ peak temperature of the component (A) is -25°C or lower.
[15]
The composition for a foam according to any one of [1] to [14] above, wherein the content of the component (A) is 5 to 40 parts by mass based on 100 parts by mass of the foamable polymer.
[16]
The composition for a foam according to any one of [1] to [15] above, wherein the content of the component (A) is 5 to 30 parts by mass based on 100 parts by mass of the foamable polymer.
[17]
(C) further comprising an ethylene polymer,
The composition for a foam according to any one of [1] to [16] above, wherein the content of the component (C) is 45 parts by mass or less based on 100 parts by mass of the foamable polymer.
[18]
The composition for a foam according to [17] above, wherein the content of the component (C) is 5 to 40 parts by mass based on 100 parts by mass of the foamable polymer.
[19]
The composition for a foam according to [17] or [18], wherein the content of the component (C) is 5 to 30 parts by mass based on 100 parts by mass of the foamable polymer.
[20]
(A) a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit; and (B) an ethylene/polar monomer copolymer having a crosslinked structure;
The content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass,
A foam in which the hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100% by mass,
In the foam, the (A) component is 5 to 50 parts by mass, and the (B) component is 50 to 95 parts by mass, relative to 100 parts by mass of the foamable polymer containing the (A) component and the (B) component. ,Contains ,foam.
[21]
The foam according to [20] above, which is a midsole.
[22]
(A) a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit;
(B) an ethylene/polar monomer copolymer;
(D) a crosslinking agent;
(E) a foaming agent;
and the content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass,
A method for producing a foam using a foam composition, wherein the hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100% by mass,
In the foam composition, the content of the component (A) is 5 to 50 parts by mass, based on 100 parts by mass of the foamable polymer containing the components (A) and (B), and the content of the component (B) is 5 to 50 parts by mass. The content is 50 to 95 parts by mass,
Melting and kneading the foam composition to obtain a melt-kneaded product;
heating and/or irradiating the molten kneaded material with energy rays;
A method for producing a foam, comprising:
[23]
(A) a conjugated diene copolymer and/or hydrogenated product thereof containing a conjugated diene monomer unit and a vinyl aromatic monomer unit;
(B) an ethylene/polar monomer copolymer;
(D) a crosslinking agent;
and the content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass,
A method for producing a foam using a foam composition in which the hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100% by mass,
In the foam composition, the content of the component (A) is 5 to 50 parts by mass, based on 100 parts by mass of the foamable polymer containing the component (A) and the component (B). The content of is 50 to 95 parts by mass,
kneading the foam composition to obtain a kneaded product;
a step of molding and crosslinking the kneaded material to obtain a crosslinked molded product;
A method for producing a foam, comprising the steps of: (E) impregnating the crosslinked molded product with a foaming agent, and then foaming it by reducing the pressure.

According to the present invention, it is possible to provide a composition for a foam that provides a foam with an excellent balance of impact resilience and tear strength and high dimensional stability against heat even when the composition is reduced in weight.

Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail. The present embodiment below is an illustration for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be implemented with appropriate modifications within the scope of its gist.

As used herein, "as a main component" refers to a block containing 70% by mass or more of monomer units. For example, in the case of a "polymer block mainly composed of A units", it means that the block contains 70% by mass or more of A (monomer) units.

[Foam composition]
The foam composition of the present embodiment is a composition before foaming, and includes (A) a conjugated diene copolymer (hereinafter referred to as ) and (E) a blowing agent (hereinafter sometimes referred to as component (E)), and the vinyl aromatic monomer in component (A). The content of the unit is 5 to 15% by mass, the hydrogenation rate of the conjugated diene monomer unit in the component (A) is 30 to 100% by mass, and the ( This is a foam composition in which the content of the component (A) is 5 to 50 parts by mass based on 100 parts by mass of the foamable polymer containing the component A).
According to the composition for a foam having the above structure, a foam with an excellent balance of impact resilience and tear strength and high dimensional stability against heat can be obtained even when the weight is reduced.

In addition, the foam composition of the present embodiment is a composition before crosslinking and foaming, and in addition to the above-mentioned structure, it also contains (B) an ethylene/polar monomer copolymer (hereinafter referred to as the (B) component). ) and (D) a crosslinking agent (hereinafter sometimes referred to as component (D)), the composition for a foam comprising (A) in the foam composition. The foam composition contains 5 to 50 parts by mass of the component (A) and 50 to 95 parts by mass of the component (B), based on 100 parts by mass of the foamable polymer containing the component (B). is preferred.
According to the composition for a foam having the above structure, a foam with an excellent balance of impact resilience and tear strength and high dimensional stability against heat can be obtained even when the weight is reduced.

((A) Conjugated diene copolymer)
The foam composition of the present embodiment contains (A) a conjugated diene copolymer (component (A)) containing a conjugated diene monomer unit and a vinyl aromatic monomer unit.
(A) The conjugated diene copolymer may be a block copolymer having blocks made of each monomer unit or a random copolymer, but block copolymers cannot be formed into crumbs or pellets. While being common, random copolymers are generally molded into a veil shape, so block copolymers are often preferred from the viewpoint of workability when processing into foams.

The vinyl aromatic compound forming the vinyl aromatic monomer unit contained in component (A) is not limited to the following, and any known compound can be used. For example, styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, divinylbenzene, 1,1-diphenylethylene, N , N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. These may be used alone or in combination of two or more. Among these, styrene is preferred.

<Content of vinyl aromatic monomer units in component (A)>
The content of vinyl aromatic monomer units in component (A) is 5% by mass or more from the viewpoint of tear strength of the foam, and 15% by mass or less from the viewpoint of impact resilience and dimensional stability against heat. . Within the above range, the specific gravity of the foam composition can be lowered and the weight can be reduced.
The content of vinyl aromatic monomer units in component (A) is preferably 6 to 14% by mass, more preferably 7 to 13% by mass.
The content of vinyl aromatic monomer units in component (A) can be controlled within the above range by adjusting polymerization conditions such as the amount of monomer added and polymerization time in the polymerization process of component (A). Can be done.
The content of the vinyl aromatic monomer unit in the component (A) can be measured using an ultraviolet spectrophotometer as described in the Examples below.

In addition, the content of the polymer block mainly composed of vinyl aromatic monomer units in component (A) is determined by heating the conjugated diene copolymer before hydrogenation with t-butyl hydropere under an osmium tetroxide catalyst The above-mentioned value obtained from the method of oxidative decomposition using oxide (method described in I.M. KOLTHOFF, et al., Polym. Sci., 1, 429 (1946)) (hereinafter referred to as "osmium tetroxide decomposition method") It can be calculated using the mass of the polymer block mainly composed of vinyl aromatic monomer units in the conjugated diene copolymer before hydrogenation. In addition, in the osmium tetroxide decomposition method, a polymer block mainly composed of vinyl aromatic monomer units having an average degree of polymerization of about 30 or more can be detected.

The content of the polymer block mainly composed of vinyl aromatic monomer units in component (A) is the same as that of Y. Tanaka, et al. , RUBBER CHEMISTRY and TECHNOLOGY, 54, 685 (1981), and can be measured using a nuclear magnetic resonance apparatus (NMR). This method is hereinafter referred to as the NMR method.
The NMR method will be specifically explained by taking as an example a conjugated diene copolymer in which the vinyl aromatic monomer unit is styrene and the conjugated diene monomer unit is 1,3-butadiene.
Proton nuclear magnetic resonance ( ¹ H-NMR) is measured using a sample in which 30 mg of the hydrogenated conjugated diene copolymer is dissolved in 1 g of deuterated chloroform. In the measurement results obtained, by calculating the ratio of the integrated value to the total integrated value in the range where the chemical shift is 6.9 ppm to 6.3 ppm, the polymer block mainly composed of vinyl aromatic monomer units (in this case , a polystyrene block) (hereinafter referred to as "Ns value") can be determined. More specifically, it can be determined using the following equations (7) to (10).
Block styrene strength (b-St strength)
= (integrated value of 6.9ppm to 6.3ppm)/2 (7)
Random styrene strength (r-St strength)
=(integrated value of 7.5ppm to 6.9ppm)-3×(b-St) (8)
Ethylene/butylene strength (EB strength)
= Total integrated value - 3 x {(b-St intensity) + (r-St intensity)}/8 (9)
Polystyrene block content (Ns value) measured by NMR method
=104×(b-St intensity)
/[104×{(b-St intensity)+(r-St intensity)}+56×(EB intensity)](10)
Here, the content (Os value) of polymer blocks mainly composed of vinyl aromatic monomer units in the conjugated diene copolymer before hydrogenation measured by the osmium tetroxide decomposition method and the content (Os value) measured by the NMR method. The following formula (11) can be established between the content (Ns value) of polymer blocks mainly composed of vinyl aromatic monomer units in the conjugated diene copolymer after hydrogenation. Are known.
Os value = -0.012 x (Ns value) ² +1.8 x (Ns value) -13.0 (11)

The conjugated diene forming the conjugated diene monomer unit contained in component (A) is a diolefin having a conjugated double bond. The diolefin is not limited to the following, and any known diolefin can be used. For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-cyclopentadiene, 2-methyl-1,3-pentadiene, myrcene, 2-methyl -1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 2-phenyl-1,3-butadiene, 2-phenyl-1,3-pentadiene, 3-phenyl -1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 2-hexyl-1,3-butadiene, 1,3-hexadiene, 1,3-cyclo Examples include hexadiene, 3-methyl-1,3-hexadiene, 2-benzyl-1,3-butadiene, 2-p-tolyl-1,3-butadiene, and farnesene.
These may be used alone or in combination of two or more. Among these, 1,3-butadiene is preferred.

When a polymer chain consisting of 1,3-butadiene (for example, polybutadiene) is exposed to heat, light, or radicals, when the H of the C-H bond in the polymer chain is extracted and carbon radicals are generated, the generated carbon radicals become polybutadiene. tends to cause addition reactions with the double bonds of , resulting in crosslinking. Therefore, when 1,3-butadiene is used as the conjugated diene to form a foam, the melt tension tends to improve and foam cells tend to be stably generated. On the other hand, in a polymer chain made of isoprene (for example, polyisoprene), when heat, light, or radicals pull out the H of the C-H bond in the polymer chain and generate carbon radicals, the generated carbon radicals can interact with oxygen. There is a tendency to cause amputation due to the reaction of For this reason, when isoprene is used as the conjugated diene to form a foam, the melt tension tends to decrease, making it difficult to stably generate bubbles in the foam. In addition, since hydrogenated polybutadiene is relatively easy to crystallize, crystallization during stretching tends to improve tensile strength and tear strength and improve the durability of the foam. On the other hand, since hydrogenated polyisoprene is relatively difficult to crystallize, it is difficult to improve tensile strength and tear strength even during stretching, and the durability of the foam tends to be difficult to improve compared to polybutadiene.
The content of conjugated diene monomer units in component (A) is preferably 85 to 95% by mass. Within this range, a foam that is flexible and has excellent resilience properties can be obtained.

<Hydrogenation rate of conjugated diene monomer units in component (A)>
The hydrogenation rate of the double bond of the conjugated diene monomer unit of component (A) is 30 to 100% by mass, preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and 95 to 100% by mass. % is more preferable.
In this embodiment, since the hydrogenation rate of the double bond of the conjugated diene monomer unit of component (A) is within the above range, the crosslinking speed during molding is slow, so there is less crosslinking unevenness and fine and uniform Furthermore, since the degree of closed cells is increased, the foam can be made into a foam that has an excellent balance of impact resilience and tear strength even if it is lightweight, and has high dimensional stability against heat. In particular, when the (B) ethylene/polar monomer copolymer described below is general-purpose EVA, if the hydrogenation rate of the (A) component is 50 to 100% by mass, the crosslinking of the (A) and (B) components It is easy to keep the reaction rate at the same level, and it tends to be easy to form uniform crosslinks. In addition, when the hydrogenation rate of the conjugated diene monomer unit of component (A) is 95 to 100% by mass, crystallinity appears in the block containing the conjugated diene monomer unit, which reduces the tensile strength of the foam and the tear resistance. There is a tendency for the strength to improve and the durability of the foam to improve.
In the hydrogenation reaction of component (A), the hydrogenation rate of the double bond of the conjugated diene monomer unit of component (A) is determined by the type of hydrogenation catalyst, the amount added, the amount of hydrogen added, temperature, pressure, hydrogenation By adjusting the time etc., it is possible to control within the above numerical range.
The hydrogenation rate of the conjugated diene monomer unit of component (A) can be measured by the method shown in the Examples below.

<Structure of component (A)>
Component (A) may contain other polymerizable monomers as structural units other than conjugated diene monomer units and vinyl aromatic monomer units, as long as the purpose of this embodiment is not impaired. .
The structure of component (A) is not particularly limited, but it is preferably a copolymer containing a conjugated diene monomer unit using 1,3-butadiene and a vinyl aromatic monomer unit using styrene.
Specifically, a block copolymer consisting of a polymer block mainly composed of styrene and a polymer block mainly composed of 1,3-butadiene is more preferable. More specifically, a block copolymer having a block structure of styrene block-1,3-butadiene block-styrene block, etc. may be mentioned. As a result, the styrene blocks become physical crosslinking points, resulting in elasticity.

<1,2-vinyl bond amount and 3,4-vinyl bond amount of component (A)>
The amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds (hereinafter sometimes abbreviated as "vinyl bond amount") in the conjugated diene monomer unit of component (A) is not particularly limited. , preferably 10 to 60% by mass.
Here, the amount of vinyl bonds is the sum of the amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds. In addition, the amount of vinyl bonds is the amount of vinyl bonds before hydrogenation, and is the amount of vinyl bonds that are incorporated into the polymer through 1,4-bonds (including cis and trans) in the conjugated diene copolymer before hydrogenation. The conjugated diene monomer moiety incorporated into the polymer through the 1,2-vinyl bond and the 3,4-vinyl bond (hereinafter referred to as the "1,4-bonding moiety") (referred to as "vinyl bonding moiety").
The lower limit of the vinyl bond amount is more preferably 15% by mass or more, and even more preferably 25% by mass or more. The upper limit is more preferably 50% by mass or less, and even more preferably 45% by mass or less.
When the amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of component (A) is 10 to 60% by mass or more, the production of a conjugated diene copolymer (A) They tend to be good at sex.
If the amount of vinyl bonds is low, the viscosity of component (A) increases, so it is necessary to increase the reaction temperature and the power performance of the reactor and conveyor. Furthermore, when the amount of vinyl bonds is high, the viscosity of the component (A) decreases, but it tends to become sticky and polymer blocking tends to occur. Furthermore, if the amount of vinyl bonds is too low, component (A) tends to crystallize, especially after hydrogenation, and the foam tends to become hard and its resilience performance to deteriorate. On the other hand, if the amount of vinyl bonds is too high, component (A) will have a high Tg after hydrogenation, and the foam of this embodiment will tend to have poor resilience properties.

The amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of component (A) is controlled within the above numerical range by adjusting the amount of vinylating agent and polymerization temperature described below. be able to. When the amount of vinylizing agent is increased or the polymerization temperature is adjusted to a low value, the amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds tend to increase.
For example, when using 1,3-butadiene as the conjugated diene monomer, normal butyllithium (NBL) as the polymerization initiator, and N,N,N',N'-tetramethylethylenediamine (TMEDA) as the vinylizing agent, In order to control the amount of 1,2-vinyl bonds to 10% by mass, it is preferable to control TMEDA to 0 to 0.05 mol per mol of NBL and the polymerization temperature to 60°C to 70°C. On the other hand, in order to control the amount of 1,2-vinyl bonds to 60% by mass, it is preferable to control TMEDA to 0.5 to 1 mol and the polymerization temperature to 50°C to 70°C per 1 mol of NBL. .
The amount of vinyl bonds can be measured by the method shown in the Examples below.

<Peak top molecular weight of component (A)>
The peak top molecular weight of component (A) is not particularly limited, but is usually 10,000 or more, preferably 80,000 to 200,000, more preferably 100,000 to 150,000, and even more preferably 110,000 to 140,000. Ten thousand.
When the peak top molecular weight of the component (A) is within the above numerical range, the productivity of the conjugated diene copolymer (A) and the processability of the foam composition of this embodiment tend to be excellent.
The peak top molecular weight of component (A) can be controlled within the above numerical range by adjusting the polymerization conditions such as the amount of monomer added, amount of polymerization initiator, polymerization time, and polymerization temperature in the polymerization process of component (A). can.

<Fluidity of component (A)>
The fluidity of component (A) is not particularly limited, but the melt flow rate (MFR, 230°C, 2.16 kg) of component (A) is preferably 1.0 g/10 min or more, more preferably is 1.5 g/10 min or more, more preferably 3.0 g/10 min or more.
The upper limit is preferably 15 g/10 min or less, more preferably 10 g/10 min or less, even more preferably 9 g/10 min or less.
When the MFR of the component (A) is 15 g/10 min or less, when the foam composition of this embodiment is injection-molded or press-molded, there are few burrs that protrude from the mold, which tends to suppress raw material loss. .
In general, in foam compositions, (D) the crosslinking agent is mixed in a low temperature range where the foaming properties of the foaming agent do not develop.・When composed of a polar monomer copolymer and (C) an ethylene polymer (hereinafter sometimes referred to as component (C)), these components are not completely compatible. do not. Furthermore, structural differences among component (A), component (B), and component (C) also affect the compatibility of the components. Therefore, it is thought that the characteristics of each component alone are likely to be exhibited in the foam composition, and if the fluidity of component (A) is high, burrs will increase.
When the MFR of the component (A) is 1.0 g/10 min or more, the component (A) tends to be easily mixed with the component (B) and/or the component (C), and there is a tendency for there to be less undissolved material. Therefore, it contributes to the formation of a uniform foam, suppresses undissolved parts, and mixes component (A) in the desired ratio, which tends to easily exhibit the desired impact resilience and dimensional stability. It is in.
The MFR of component (A) mainly depends on the molecular weight of component (A), the hydrogenation rate, the content of vinyl aromatic monomer units, and the amount of vinyl bonds in the conjugated diene monomer units. When the content of the vinyl aromatic monomer unit of component (A) is 5 to 15% by mass, the hydrogenation rate is 95% or more, and the peak top molecular weight is 80,000 to 200,000, the vinyl bond amount is 100,000 to 200,000. The MFR can be controlled within the range of 1.0 to 15 g/10 min within a range of 60%. The higher the molecular weight, hydrogenation rate, and content of vinyl aromatic monomer units, the lower the MFR of component (A), and the lower the amount of vinyl bonds in the conjugated diene monomer unit, the lower the MFR of component (A). Become.
The MFR of component (A) can be controlled within the above numerical range by adjusting polymerization conditions such as the amount of monomer added, the amount of polymerization initiator, polymerization time, and polymerization temperature in the polymerization step of component (A). The MFR of component (A) can be measured by the method described in the Examples below.

<Foamable polymer>
In the foam composition of the present embodiment, the content of the component (A) is 5 to 50 parts by mass based on 100 parts by mass of the foamable polymer containing the component (A) in the foam composition. It is. The amount is preferably 5 to 40 parts by weight, more preferably 5 to 30 parts by weight.
Moreover, it is preferable that the foam composition of this embodiment further contains (B) an ethylene/polar monomer copolymer and (D) a crosslinking agent. In such a case, in the foam composition of the present embodiment, the content of the component (A) is not particularly limited with respect to 100 parts by mass of the foamable polymer containing the component (A) and the component (B). is preferably 5 to 50 parts by weight, and the content of component (B) is preferably 50 to 95 parts by weight.
The content of component (A) relative to 100 parts by mass of the foamable polymer is more preferably 5 to 40 parts by mass, more preferably 5 to 30 parts by mass. Further, the content of component (B) is more preferably 55 to 90 parts by mass, and even more preferably 60 to 85 parts by mass.
By setting the content of component (A) and component (B) to the above, the foam composition and foam of this embodiment tend to have excellent impact resilience, balance of tear strength, and dimensional stability against heat. .
In this specification, the "foamable polymer" is a polymer that can be foamed regardless of whether it is physically or chemically, and may contain components other than component (A). Foamed polymers other than the component (A) are not particularly limited, but include the component (B) described above and the component (C) described below.
When the foamable polymer contains only components (A) and (B), the amount of these (A) + (B) is the standard of 100 parts by mass, and when it further contains component (C), the amount of (A) )+(B)+(C) is regarded as 100 parts by mass, and the ratio of each component is set.
Expandable polymers that are blended in addition to components (A) and (B) are not limited to component (C) described below, and as long as they exhibit foaming properties, such polymers are included in the "expandable polymers". The value is the reference value.
Here, regarding the polymer in the foam composition of the present embodiment, the (A) component, the (B) component, the (C) component blended as necessary, and other heavy components blended as necessary. All of the following apply.

<Tanδ peak temperature of component (A)>
The tan δ peak temperature of component (A) is preferably −25° C. or lower from the viewpoint of repulsion characteristics under low temperature conditions. The temperature is more preferably -30°C or lower, and even more preferably -35°C or lower.
The tan δ peak temperature of component (A) can be measured using a dynamic viscoelasticity measurement device. For example, it can be measured using ARES-G2 (manufactured by TA Instruments). A 2 mm thick sheet of component (A) is compression molded at a temperature of about 200°C, where component (A) melts, the sheet is cut into a 12.6 x 40 mm strip, and this sample is measured at a temperature of -100°C. A strain of 0.5% is applied while increasing the temperature at 3° C./min, and the peak temperature is obtained by plotting tan δ at each temperature.
The tan δ peak temperature of component (A) is determined by the amount of vinyl bonds in the conjugated diene monomer unit, the hydrogenation rate, and the conjugated diene monomer in the copolymer block consisting of the conjugated diene monomer unit and the vinyl aromatic monomer unit. It can be controlled within the above numerical range by changing the composition ratio of the unit and the vinyl aromatic monomer unit.

<Method for producing component (A)>
The method for producing component (A) is not particularly limited, and any known method can be used. For example, it may include a polymerization step and a hydrogenation step as described below.
The polymerization step is not particularly limited, but for example, living anion polymerization in which a conjugated diene and a vinyl aromatic compound are polymerized using an organic alkali metal compound as a polymerization initiator in a hydrocarbon solvent can be used to form a homopolymer or a random copolymer. These include steps of coalescence and/or obtaining a block copolymer.

The hydrocarbon solvent is not particularly limited, and any known solvent can be used. For example, aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and methylcycloheptane; benzene, Examples include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene. These hydrocarbon solvents may be used alone or in combination of two or more.

As the polymerization initiator, organic alkali metal compounds can be used, including but not limited to aliphatic hydrocarbons that are generally known to have anionic polymerization activity toward conjugated diene compounds and vinyl aromatic compounds. Examples include alkali metal compounds, aromatic hydrocarbon alkali metal compounds, organic amino alkali metal compounds, and the like.
Examples of alkali metals include lithium, sodium, potassium, and the like.
Suitable organic alkali metal compounds include aliphatic and aromatic hydrocarbon lithium compounds having 1 to 20 carbon atoms, specifically, compounds containing one lithium in one molecule, and compounds containing multiple lithium in one molecule. Examples include dilithium compounds, trilithium compounds, and tetralithium compounds containing lithium. More specifically, n-propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, tolyllithium, diisopropenylbenzene and Examples include a reaction product of sec-butyllithium, a reaction product of divinylbenzene, sec-butyllithium, and 1,3-butadiene, and the like.

The total amount of 1,2-vinyl bonds and 3,4-vinyl bonds in the conjugated diene monomer units of component (A) is controlled by using a Lewis base (for example, ether, amine, etc.) as a vinylating agent. can. The amount of vinylating agent used is adjusted depending on the desired amount of vinyl bonding.
Examples of the vinylizing agent include, but are not limited to, ether compounds, ether compounds having two or more oxygen atoms, and tertiary amine compounds.

Examples of the ether compound include linear ether compounds and cyclic ether compounds.
Examples of linear ether compounds include, but are not limited to, dialkyl ether compounds of ethylene glycol such as dimethyl ether, diethyl ether, diphenyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether, and diethylene glycol. Dialkyl ether compounds of diethylene glycol such as dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol dibutyl ether are mentioned.
Examples of cyclic ether compounds include, but are not limited to, tetrahydrofuran, dioxane, 2,5-dimethyloxolane, 2,2,5,5-tetramethyloxolane, 2,2-bis(2-oxolanyl) ) propane, and alkyl ethers such as furfuryl alcohol.

Examples of tertiary amine compounds include, but are not limited to, pyridine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, 1,2- Dipiperidinoethane, trimethylaminoethylpiperazine, N,N,N',N",N"-pentamethylethylenetriamine, N,N'-dioctyl-p-phenylenediamine, trimethylamine, triethylamine, tributylamine, N, Examples include N-dimethylaniline, N-ethylpiperidine, N-methylpyrrolidinetetramethylpropanediamine, 1,2-dipiperidinoethane, and bis[2-(N,N-dimethylamino)ethyl]ether.
As the tertiary amine compound, a compound having two amines is preferred. Furthermore, among them, those having a structure showing symmetry within the molecule are more preferable, such as N,N,N',N'-tetramethylethylenediamine and bis[2-(N,N-dimethylamino)ethyl] More preferred are ether and 1,2-dipiperidinoethane.
The above-mentioned vinylating agents may be used alone or in combination of two or more.

After the polymerization step, the conjugated diene copolymer can be hydrogenated by a conventionally known method.
The hydrogenation method in the hydrogenation step is not particularly limited, but examples include a method of hydrogenating the conjugated diene copolymer obtained in the above polymerization step by supplying hydrogen gas in the presence of a hydrogenation catalyst. It will be done. By including the hydrogenation step, double bond residues in the conjugated diene monomer units are hydrogenated, and a more thermally stable hydrogenated conjugated diene copolymer can be obtained.
The hydrogenation rate can be controlled by, for example, the amount of catalyst during hydrogenation and the amount of hydrogen gas supplied (hereinafter also referred to as "feed"). Further, the hydrogenation rate can be controlled by, for example, the amount of catalyst during hydrogenation, the amount of hydrogen gas supplied, the pressure of hydrogen gas, and the reaction temperature. The hydrogenation step is preferably carried out at a timing after the production reaction of the conjugated diene copolymer in the polymerization step has stopped.
A stabilizer may be added after the hydrogenation reaction is completed. The stabilizer is not particularly limited, but includes, for example, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate.

The hydrogenation catalyst is not particularly limited, and conventionally known hydrogenation catalysts can be used. Specifically, supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, and Ru are supported on carbon, silica, alumina, diatomaceous earth, etc.; organic acid salts such as Ni, Co, Fe, and Cr; Or a homogeneous system such as a so-called Ziegler type hydrogenation catalyst using a transition metal salt such as an acetylacetone salt and a reducing agent such as an organic aluminum, or a so-called organometallic complex such as an organometallic compound such as Ti, Ru, Rh, or Zr. Examples include hydrogenation catalysts, etc. Among these, preferred hydrogenation catalysts include titanocene compounds and reducing organometallic compounds.

The reaction conditions for the hydrogenation reaction are not particularly limited, but it is usually carried out at a temperature range of 0 to 200°C, more preferably 30 to 150°C. The hydrogen pressure in the hydrogenation reaction is not particularly limited, but is usually 0.1 to 15 MPa, preferably 0.2 to 10 MPa, and more preferably 0.3 to 5 MPa. Further, the hydrogenation reaction time is usually 3 minutes to 10 hours, preferably 10 minutes to 5 hours. The hydrogenation reaction can be a batch process, a continuous process, or a combination thereof.

From the solution of the conjugated diene copolymer obtained through the above-mentioned polymerization step and hydrogenation step, the catalyst residue can be removed and the conjugated diene copolymer can be separated from the solvent, if necessary.
The method for separating the conjugated diene copolymer is not particularly limited, and for example, a polar solvent such as acetone or alcohol, which is a poor solvent for the conjugated diene copolymer after hydrogenation, is added to the reaction solution after hydrogenation. In addition, there are methods for recovering the conjugated diene copolymer by precipitating it, pouring a solution of the conjugated diene copolymer into boiling water with stirring, removing the solvent by steam stripping, and recovering the conjugated diene copolymer directly. Examples include a method of heating a solution of a conjugated diene copolymer to distill off the solvent.

(A) Stabilizers such as various phenol stabilizers, phosphorus stabilizers, sulfur stabilizers, and amine stabilizers can be added to the conjugated diene copolymer.

Component (A) may have a functional group. The method for making the component (A) have a functional group is not particularly limited, but includes, for example, a method of using a polymerization initiator having a functional group in the polymerization reaction in the polymerization step; A method using an unsaturated monomer having Further, a functional group may be added by a modification reaction, and such a modification reaction method includes a method in which a modifier having a functional group is added to the living end of the conjugated diene polymer obtained by the polymerization reaction in the polymerization step. Can be mentioned.
Specifically, the conjugated diene copolymer after polymerization can be functionalized by reacting with a functional group-containing compound.
There are no particular limitations on the site into which the functional group is introduced, the number of functional groups, etc., but from the viewpoint of the physical properties of the foam of this embodiment, it is preferable to modify the terminal end of the polymer chain and convert it into a functional group.
Examples of functional groups include hydroxyl group, carbonyl group, thiocarbonyl group, acid halide group, acid anhydride group, carboxyl group, thiocarboxylic acid group, aldehyde group, thioaldehyde group, carboxylic acid ester group, amide group, and sulfone group. Acid group, sulfonic acid ester group, phosphoric acid group, phosphoric acid ester group, amino group, imino group, cyano group, pyridyl group, quinoline group, epoxy group, thioepoxy group, sulfide group, isocyanate group, isothiocyanate group, halogenated Examples include a silicon group, a silanol group, an alkoxysilane group, a tin halide group, an alkoxytin group, and a phenyltin group. Among these, from the viewpoint of the physical property balance of the foam, at least one selected from the group consisting of hydroxyl groups, carbonyl groups, acid anhydride groups, carboxyl groups, epoxy groups, amino groups, and silanol groups is preferred.

Examples of the "polymerization initiator having a functional group" include, but are not limited to, 3-lithio-1-[N,N-bis(trimethylsilyl)]aminopropane, 2-lithio-1-[N,N- bis(trimethylsilyl)]aminoethane, 3-lithio-2,2-dimethyl-1-[N,N-bis(trimethylsilyl)]aminopropane, 2,2,5,5-tetramethyl-1-(3-lithiopropyl )-1-aza-2,5-disilacyclopentane, 2,2,5,5-tetramethyl-1-(3-lithio-2,2-dimethyl-propyl)-1-aza-2,5- Disilacyclopentane, 2,2,5,5-tetramethyl-1-(2-lithioethyl)-1-aza-2,5-disilacyclopentane, 3-lithio-1-[N-(tert-butyl) -dimethylsilyl)-N-trimethylsilyl]aminopropane, 3-lithio-1-(N-methyl-N-trimethylsilyl)aminopropane, 3-lithio-1-(N-thyl-N-trimethylsilyl)aminopropane, and lithium Examples include piperidide.

Examples of the "unsaturated monomer having a functional group" include, but are not limited to, p-[N,N-bis(trimethylsilyl)amino]styrene, p-[N,N-bis(trimethylsilyl)aminomethyl ] Styrene, p-{2-[N,N-bis(trimethylsilyl)amino]ethyl}styrene, m-[N,N-bis(trimethylsilyl)amino]styrene, p-(N-methyl-N-trimethylsilylamino) Examples include styrene and p-(N-methyl-N-trimethylsilylaminomethyl)styrene.

Examples of the "modifier having a functional group" include, but are not limited to, tetraglycidyl metaxylene diamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, ε-caprolactone, 1,3-dimethyl -2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N'-dimethylpropyleneurea, and N-methylpyrrolidone.

The method for producing the conjugated diene copolymer (A) having a functional group is not particularly limited, and any known method can be used. For example, a method in which an unfunctionalized conjugated diene copolymer is heated and melted (100 to 300°C) and reacted with a functional group-containing compound, a method in which solution polymerization is carried out using an organic solvent, and an unfunctionalized method in a slurry state. Examples include a method in which a conjugated diene copolymer is reacted with a functional group-containing compound at 0 to 150°C.

The method for epoxidizing the conjugated diene copolymer is not particularly limited, and examples thereof include the method described in JP-A-6-220124. It can be epoxidized by reacting with an epoxidizing agent such as the following.
Peracids are not particularly limited, and examples thereof include performic acid, peracetic acid, perbenzoic acid, trifluoroperacetic acid, and the like. Among these, peracetic acid is preferred because it is produced industrially in large quantities, is available at low cost, and has high stability.
Hydroperoxides are not particularly limited, and examples thereof include hydrogen peroxide, tert-butyl hydroperoxide, and cumene peroxide.
When carrying out the epoxidation reaction, a catalyst can be used as necessary. For example, when performing an epoxidation reaction using peracids, an alkali such as soda carbonate or an acid such as sulfuric acid can be used as a catalyst. When using hydroperoxides as epoxidizing agents, a mixture of tungstic acid and caustic soda is used in combination with hydrogen peroxide, an organic acid with hydrogen peroxide, or molybdenum hexacarbonyl with tert-butyl hydroperoxide to achieve a catalytic effect. Obtainable.
The epoxidation reaction of a conjugated diene copolymer can be carried out by adjusting reaction conditions such as whether or not a solvent is used and the reaction temperature, depending on the reaction apparatus used, the physical properties of the raw materials, etc. For example, the reaction temperature can be selected depending on the reactivity of the epoxidizing agent used. When using peracetic acid, which is a preferred epoxidizing agent, the reaction temperature is preferably 0 to 70°C. By setting the above reaction temperature, it is possible to increase the reaction rate while suppressing the decomposition reaction of peracetic acid.

The method for converting the conjugated diene copolymer into an acid anhydride group is not particularly limited, and examples thereof include the method described in JP-A-62-79211. Examples include a method in which a copolymer is graft-modified with an α,β-unsaturated carboxylic acid or a derivative thereof, such as its anhydride, esterified product, amidated product, imidized product, etc.
Examples of the α,β-unsaturated carboxylic acid or its derivative include maleic anhydride, maleic anhydride, acrylic acid or its ester, methacrylic acid or its ester, endo-cis-bicyclo [2.2.1] Examples include -5-heptene-2,3-dicarboxylic acid or its anhydride.
The amount of α,β-unsaturated carboxylic acid or its derivative added is not particularly limited, but is usually 0.01 to 20 parts by mass, preferably 0.01 to 20 parts by mass, per 100 parts by mass of the conjugated diene copolymer after hydrogenation. .1 to 10 parts by mass. The reaction temperature for graft modification is not particularly limited, but is preferably 100 to 300°C, more preferably 120 to 280°C.

((B) Ethylene/polar monomer copolymer)
The foam composition of this embodiment preferably contains (B) an ethylene/polar monomer copolymer (component (B)).
(B) Ethylene/polar monomer copolymer is a copolymer containing ethylene and a polar monomer as constituent units.
The polar monomer is not particularly limited, and known ones can be used. Examples include unsaturated carboxylic acids, salts thereof, esters thereof, amides thereof, vinyl esters, carbon monoxide, and the like. More specifically, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride, itaconic anhydride, lithium and sodium of these unsaturated carboxylic acids, Salts of monovalent metals such as potassium, salts of polyvalent metals such as magnesium, calcium, zinc, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, methacrylic acid Examples include unsaturated carboxylic acid esters such as methyl, ethyl methacrylate, isobutyl methacrylate, and dimethyl maleate, vinyl esters such as vinyl acetate and vinyl propionate, carbon monoxide, and sulfur dioxide.

(B) The ethylene/polar monomer copolymer is not particularly limited, and any known copolymer can be used. For example, ethylene/unsaturated carboxylic acid copolymers such as ethylene/acrylic acid copolymers and ethylene/methacrylic acid copolymers; some or all of the carboxyl groups of the ethylene/unsaturated carboxylic acid copolymers are Ionomers neutralized with metal; ethylene/methyl acrylate copolymer, ethylene/ethyl acrylate copolymer, ethylene/methyl methacrylate copolymer, ethylene/isobutyl acrylate copolymer, ethylene/n-butyl acrylate Ethylene/unsaturated carboxylic acid ester copolymers such as copolymers; ethylene/unsaturated carboxylic acids such as ethylene/isobutyl acrylate/methacrylic acid copolymers, ethylene/n-butyl acrylate/methacrylic acid copolymers Examples include ester/unsaturated carboxylic acid copolymers and ionomers in which part or all of the carboxyl groups thereof are neutralized with the above metals; ethylene/vinyl ester copolymers such as ethylene/vinyl acetate copolymers.
Among these, copolymers of ethylene and polar monomers selected from unsaturated carboxylic acids, salts thereof, esters thereof, and vinyl acetate are particularly preferred, and ethylene/(meth)acrylic acid copolymers or ionomers thereof are particularly preferred. , an ethylene/(meth)acrylic acid/(meth)acrylic acid ester copolymer or an ionomer thereof, and an ethylene/vinyl acetate copolymer are preferable, and an ethylene/vinyl acetate copolymer is more preferable.

(B) The ethylene/polar monomer copolymer preferably has a polar monomer content of usually 1 to 50% by mass, more preferably 5 to 45% by mass, although it varies depending on the type of polar monomer. .

When the ethylene/polar monomer copolymer (B) used in the foam composition of this embodiment is an ethylene/vinyl acetate copolymer, the content of vinyl acetate (VA) in the ethylene/vinyl acetate copolymer The amount is usually 10 to 45% by weight, preferably 15 to 35% by weight, more preferably 15 to 25% by weight. The higher the VA content, the lower the hardness of the foam of this embodiment, and the more impact resilience tends to improve. On the other hand, tear strength, compression set, and dimensional stability against heat tend to deteriorate. From the viewpoint of the balance of these properties, the content of vinyl acetate is preferably within the above numerical range.

In the foam composition of this embodiment, the ethylene/polar monomer copolymer (B) may be used alone or in combination of two or more.

The content of component (B) in the foam composition of the present embodiment is preferably 50 to 95 parts by mass per 100 parts by mass of the expandable polymer in the foam composition. More preferably 55 to 90 parts by weight, still more preferably 60 to 85 parts by weight. By setting the component (B) in the above content, the foam of this embodiment has excellent impact resilience, balance of tear strength, and dimensional stability against heat.

((C) Ethylene polymer)
The foam composition of the present embodiment preferably contains (C) an ethylene polymer (component (C)), if necessary.
Component (C) is a polymer containing ethylene as a structural unit.
(C) The ethylene polymer is not particularly limited, and known polymers can be used. Examples of ethylene-based polymers include polyethylene (PE), which is a polymer of ethylene, and ethylene/α-, which is a low-crystalline random copolymer consisting of ethylene and an α-olefin having 3 to 10 carbon atoms. Examples include olefin copolymers, block copolymers containing ethylene and α-olefin (for example, multi-block copolymers in which the hard segment is crystalline polyethylene and the soft segment is a random block of ethylene-octene), etc. .

In the foam composition of this embodiment, when polyethylene is used as the component (C), its type is not limited, and any known polyethylene can be used. Examples include high-density polyethylene, ultra-high molecular weight high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene.

As component (C), three or more types of copolymers consisting of ethylene and two or more types of compounds other than ethylene may be used. For example, copolymers (terpolymers) made of ethylene and two types of α-olefins, copolymers made of ethylene, α-olefins, and unsaturated carboxylic acids (acrylic acid, methacrylic acid, maleic acid, etc.) Polymers crosslinked with metal ions such as Na ⁺ , K ⁺ , Ag ⁺ , Cu ²⁺ , Ba ²⁺ , Zn ²⁺ and Fe ²⁺ (ionomers) can also be used.

(C) The ethylene copolymer may be used alone or in combination of two or more. Among the above-mentioned ethylene-based copolymers, (C) ethylene-based It is preferable to use it as a copolymer, and more preferably an ethylene/α-olefin copolymer consisting of ethylene and an α-olefin having 3 to 10 carbon atoms. An ethylene/α-olefin copolymer consisting of ethylene is more preferred, and an ethylene/α-olefin copolymer consisting of ethylene and propylene or 1-butene having 3 to 4 carbon atoms is even more preferred.
(C) Ethylene/α-olefin copolymer can be obtained by a known polymerization method. Examples include a method of polymerizing a predetermined monomer in an inert solvent such as hexane, heptane, toluene, or xylene using a polymerization catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst.

In the foam composition of the present embodiment, the content of component (C) is preferably 45 parts by mass or less, and 5 to 40 parts by mass or less, based on 100 parts by mass of the foamable polymer in the foam composition. More preferably, 5 to 30 parts by mass is even more preferred.
Note that, as described above, the foamable polymer is a polymer that can be foamed regardless of whether it is physically or chemically, and the foamable polymer in the foam composition of this embodiment is (A ) component and (B) component, and (C) component is also included in the foamable polymer.
Including component (C) in addition to components (A) and (B) mentioned above tends to worsen the compression set of the foam, but the upper limit of component (C) should be set to 45 parts by mass or less. By doing so, it is possible to suppress a decrease in the compression set of the foam of this embodiment, and by using 5 parts by mass or more, a foam with even better tear strength can be obtained.

(Other foamable polymers)
The foam composition of the present embodiment may contain other foamable polymers other than the foamable components (A), (B), and (C).
Examples of other foamable polymers include, but are not limited to, fluorine-based polymers such as fluororesin and fluororubber; polyamide resins and polyamide-based polymers such as polyamide 6, polyamide 11, polyamide 12, polyamide 6, 6, and polyamide 610; Polyamide polymers such as elastomers; polyester resins and polyester elastomers such as polyethylene terephthalate and polybutylene terephthalate; polyvinyl chloride resins; acrylic resins such as polymethyl methacrylate; silicone elastomers; butadiene rubber (BR); isoprene rubber (IR). ); Chloroprene (CR); Natural rubber (NR); Acrylonitrile butadiene rubber (NBR); Butyl rubber (IIR); Propylene homopolymer (homo PP), random polypropylene resin (random PP), block polypropylene resin (block PP), etc. Polypropylene resin; cyclic olefin polymer (COP); cyclic olefin copolymer (COC); polyurethane polymers such as polyester polyurethane resin and polyether polyurethane resin, polyurethane elastomer; polystyrene resin, acrylonitrile styrene resin (AS resin), acrylonitrile Examples include butadiene styrene resin (ABS resin).

((D) Crosslinking agent)
It is preferable that the foam composition of this embodiment contains (D) a crosslinking agent ((D) component).
Component (D) is not particularly limited, and known components can be used, and organic peroxides are preferred. For example, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(t-butylperoxy) ) hexyne-3,1,3-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis( t-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butyl peroxybenzoate, t-butyl perbenzoate, t-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, t -Butylcumyl peroxide and the like.
These may be used alone or in combination of two or more.
Among them, from the viewpoint of reactivity, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 1,1-bis(t-butyl peroxide), Peroxy)-3,3,5-trimethylcyclohexane is preferred.

The content of component (D) is not particularly limited, but is preferably 0.01 to 20 parts by mass, and preferably 0.05 to 15 parts by mass, based on 100 parts by mass of the foamable polymer in the foam composition of the present embodiment. Parts by mass are more preferred, and 0.1 to 10 parts by mass are even more preferred. With such a content, a foam with an excellent balance of various physical properties can be obtained.

((E) Foaming agent)
The foam composition of this embodiment contains a foaming agent (component (E)).
Component (E) is not particularly limited, and known components can be used. For example, azodicarbonamide (ADCA), 1,1'-azobis(1-acetoxy-1-phenylethane), dimethyl-2,2'-azobisbutyrate, dimethyl-2,2'-azobisisobutyrate , 2,2'-azobis(2,4,4-trimethylpentane), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis[N-(2-carboxyethyl)-2 -methyl-propionamidine]; Nitroso compounds such as N,N'-dinitrosopentamethylenetetramine (DPT); 4,4'-oxybis(benzenesulfonyl hydrazide), diphenylsulfone-3,3'-di Hydrazine derivatives such as sulfonyl hydrazide; semicarbazide compounds such as p-toluenesulfonyl semicarbazide; organic thermal decomposition blowing agents such as trihydrazinotriazine; bicarbonates such as sodium hydrogen carbonate and ammonium hydrogen carbonate, sodium carbonate, ammonium carbonate, etc. carbonates; nitrites such as ammonium nitrite; inorganic thermal decomposition blowing agents such as hydrogen compounds; organic physical blowing agents such as various aliphatic hydrocarbons such as methanol, ethanol, propane, butane, pentane, hexane; Examples include inorganic physical blowing agents such as air, carbon dioxide, nitrogen, argon, and water.
The physical foaming agent is a liquefied gas, a supercritical fluid, or the like, and is foamed by pressure reduction or heating. Among them, azodicarbonamide (ADCA) and sodium hydrogen carbonate are preferred from the viewpoint of cost and reactivity.

The content of component (E) in the foam composition of this embodiment is not particularly limited, and may be adjusted depending on the expansion ratio and foaming conditions, but the foamability of the foam composition of this embodiment The amount is preferably 0.1 to 30 parts by weight, more preferably 0.2 to 25 parts by weight, and even more preferably 0.3 to 20 parts by weight, based on 100 parts by weight of the polymer. With such a content, a foam with low specific gravity and an excellent balance of various physical properties can be obtained.

((F) Additive)
The foam composition of the present embodiment may contain additives, if necessary, in addition to the components (A) to (E) described above. Examples of additives include various additives such as crosslinking aids, processing aids, fillers, heat stabilizers, weather stabilizers, flame retardants, hydrochloric acid absorbers, and pigments. These additives may be used alone or in combination of two or more.

Examples of crosslinking aids include, but are not limited to, metal oxides other than zinc such as zinc oxide, magnesium oxide, and lead monoxide, metal hydroxides such as calcium hydroxide, and fatty acids such as stearic acid and oleic acid. , sulfur, p-quinonedioxime, p,p'-dibenzoylquinonedioxime, N-methyl-N-4-dinitrosoaniline, nitrosobenzene, diphenylguanidine, trimethylolpropane-N,N'-m-phenylene Peroxy crosslinking aids such as rangemaleimide; or divinylbenzene, triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate , polyfunctional methacrylate monomers such as allyl methacrylate; polyfunctional vinyl monomers such as vinyl butyrate and vinyl stearate. In particular, zinc oxide, triallyl cyanurate (TAC), and triallyl isocyanurate (TAIC) are preferred because they have an excellent crosslinking promoting effect. It is preferable to use at least zinc oxide as a crosslinking aid.

As the processing aid, a wide variety of processing aids that are generally blended into rubber can be used. Processing aids include, but are not limited to, ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate, zinc laurate, or esters. Among these, stearic acid is preferred.

Examples of the filler include, but are not limited to, clay, titanium oxide, silicon oxide, zinc oxide, talc, calcium carbonate, and the like.

Examples of the heat stabilizer include, but are not limited to, phosphorus heat stabilizers such as Irgafos 168, lactone heat stabilizers such as HP-136, sulfur heat stabilizers, and the like.

Examples of the weathering stabilizer include, but are not limited to, hindered phenol-based weathering stabilizers, phosphite-based weathering stabilizers, thioether-based weathering stabilizers, and the like.

Examples of the flame retardant include, but are not limited to, red phosphorus flame retardants, halogen flame retardants, organic phosphate ester flame retardants, inorganic flame retardants, and the like.

Examples of the hydrochloric acid absorbent include, but are not limited to, calcium stearate and the like.

Examples of pigments include, but are not limited to, azo pigments, phthalocyanine pigments, oxide pigments such as titanium oxide, chromoyl molybdate pigments, selenium sulfide compounds, ferrocyan compounds, and inorganic pigments such as carbon black. etc.

[Method for producing composition for foam]
The foam composition of this embodiment includes (A) a conjugated diene copolymer, (E) a blowing agent, and, if necessary, (B) an ethylene/polar monomer copolymer, and (C) an ethylene polymer. , (D) the crosslinking agent, and (F) the additive in a predetermined ratio by melt-mixing using a kneader.

The melt-mixing method is not particularly limited, and any known method can be used. For example, a method of melt-mixing using an extruder such as a single-screw extruder, twin-screw extruder, or multi-screw extruder, a Henschel mixer, a Banbury mixer, a roll, a kneader, etc. can be used. Alternatively, a method of removing the solvent after dissolving or dispersing each component can be used.
In this embodiment, a melt mixing method using an extruder is preferred from the viewpoint of productivity and kneading performance.

The mixing method is not particularly limited, and for example, after the polymer components in the foam composition are mixed in advance, component (E), and if necessary, component (D), component (F), etc. are added and mixed. It's okay.

The shape of the foam composition of this embodiment is not particularly limited, and can be appropriately molded into a desired shape. For example, it can be in the form of pellets, sheets (sometimes referred to as films), strands, chips, etc. For example, if necessary, each component can be mixed using a granulator or the like to form pellets.
When molding the foam composition of this embodiment into a sheet shape, the method is not particularly limited, and any known method can be used. For example, a method of forming pellets of the foam composition of the present embodiment into a sheet using an extruder or a calendar molding machine; a method of kneading each component of the foam composition of the present embodiment with a Brabender or the like; Then, methods include forming the mixture into a sheet using a calendar roll; forming a sheet using a press molding machine; and kneading the mixture using an extruder and then forming the mixture into a sheet through a T-die or an annular die. Thereby, a foamable sheet in an uncrosslinked and unfoamed state can be prepared.

[Foam]
The foam of this embodiment is a foam of the foam composition of this embodiment described above.
Specifically, the (A) component includes a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit, and the content of the vinyl aromatic monomer unit in the component (A). The amount is 5 to 15% by weight. Furthermore, the (A) component and the (B) ethylene/polar monomer copolymer have a crosslinked structure, and the hydrogenation rate of the conjugated diene monomer unit in the (A) component is 30 to 100. % by mass, and 5 to 50 parts by mass of component (A) and 5 to 50 parts by mass of component (A) per 100 parts by mass of the foamable polymer containing component (A) and component (B) in the foam. Contains 50 to 95 parts by mass of component B).
According to the above structure, even if the weight is reduced, the foam has an excellent balance of impact resilience and tear strength, and has high dimensional stability against heat.

(Applications of foam)
The foam of this embodiment can be used as a sheet (sometimes called a film), an injection molded product of various shapes, a blow molded product, a pressure molded product, a vacuum molded product, an extrusion molded product, and the like. In particular, the foam of this embodiment is lightweight and flexible, has low compression set, has excellent tear strength and impact resilience, and has excellent molding stability and processability. It can be widely used in construction-related fields, various packaging materials, daily necessities, etc. In particular, it can be suitably used as a midsole introduced between a shoe sole and an insole for the purpose of imparting various functions to shoes.

[Method for producing foam]
The first method for producing the foam of this embodiment includes the following method.
That is, (A) a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit, (B) an ethylene/polar monomer copolymer, and (D) a crosslinking agent. , (E) a blowing agent, the content of the vinyl aromatic monomer unit in the component (A) is 5 to 15% by mass, and the content of the conjugated diene monomer unit in the component (A) is 5 to 15% by mass. A method for producing a foam using a foam composition having a hydrogenation rate of 30 to 100% by mass, wherein the (A) component and the (B) component in the foam composition are The content of the component (A) is 5 to 50 parts by mass, and the content of the component (B) is 50 to 95 parts by mass, based on 100 parts by mass of the foamable polymer. The method includes a step of melt-kneading to obtain a melt-kneaded product, and a step of heating and/or irradiating the melt-kneaded product with energy rays.

The second method for producing the foam of this embodiment includes the following method.
That is, (A) a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit, (B) an ethylene/polar monomer copolymer, and (D) a crosslinking agent. , the content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass, and the hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100%. 100 parts by mass of a foamable polymer containing the component (A) and the component (B) in the foam composition, which is % by mass. , the content of the component (A) is 5 to 50 parts by mass, and the content of the component (B) is 50 to 95 parts by mass, and the foam composition is kneaded to obtain a kneaded product. a step of molding and crosslinking the kneaded product to obtain a crosslinked molded product; and a step of impregnating the crosslinked molded product with (E) a foaming agent and then foaming it by reducing the pressure.

The first manufacturing method and the second manufacturing method differ in the presence or absence of the foaming agent (E) in the stage before the foaming step and the procedure of the foaming step.
In the second manufacturing method, the product obtained at the stage of impregnating the crosslinked molded product with the foaming agent (E) corresponds to the foam composition of the present embodiment.
The first production method is preferable when using an organic or inorganic pyrolytic blowing agent, and the second production method is preferable when using an organic or inorganic physical blowing agent such as a supercritical fluid. .

A foam can be obtained by crosslinking and foaming the melt-kneaded foam composition.
According to the present embodiment, it is possible to obtain a foam that has an excellent balance between impact resilience and tear strength even when it is reduced in weight, and has excellent dimensional stability against heat, which has been difficult in the past.

The method for crosslinking the foam composition of this embodiment is not particularly limited, and any known method can be used.
Examples include (D) a method of blending a crosslinking agent and heating to crosslink, and a method of combining this method with a method of irradiating energy rays such as electron beams and radiation.

In the foam manufacturing method of this embodiment, foaming can be performed using a foaming agent that is a supercritical fluid. Such foaming methods include, for example, (1) producing crosslinked sheets, pellets, etc., placing them in a pressure-resistant container, applying pressure and temperature, and impregnating them with supercritical gas as a foaming agent; (2) A method in which pellets mixed with a crosslinking agent are placed in an injection molding machine, impregnated with supercritical gas as a foaming agent in the cylinder, and foamed simultaneously with extrusion molding or injection molding. .
In the case of the foaming method (1) above, the foaming agent is impregnated after molding without passing through a composition containing a crosslinking agent and a foaming agent at the same time. The composition obtained immediately after, that is, the composition immediately before the foaming step corresponds to the foam composition of this embodiment. The foam of this embodiment can also be manufactured by this method. The timing of crosslinking may be at the same time as molding or after molding. For example, an uncrosslinked foam composition containing a crosslinking agent may be placed in a mold heated to a temperature at which the crosslinking agent reacts, and molding and crosslinking may be performed simultaneously, or an uncrosslinked sheet may be placed at a temperature at which the crosslinking agent does not react. After molding, crosslinking may be performed by irradiating energy rays. That is, in the second manufacturing method described above, the molding step, the crosslinking step, and the foaming step do not need to be independent steps, and may be crosslinked and then foamed at the same time as molding, or crosslinked and foamed after molding. It may be foamed at the same time.

The foaming step in the method for producing a foam using the foam composition of this embodiment is not particularly limited, and can be performed using a known method such as press molding or injection molding.
For example, injection foam molding may be performed using a pelletized foam composition and a predetermined mold. When using a physical foaming agent, for example, in an injection molding machine, a supercritical physical foaming agent (e.g. nitrogen gas) is injected into a cylinder as a foaming agent, and the foaming agent is melted in the cylinder and contains other than the foaming agent. Injection molding may be performed after dispersing and melting mixing with the body composition.

Here, an example of a case where a foamable sheet formed from the foam composition of the present embodiment is foamed will be described.
The foamable sheet is cut into a size ranging from 1.0 to 1.2 times the volume of the mold and inserted into a mold maintained at 120 to 200°C. The foamable sheet is melted under pressure under conditions of a mold clamping pressure of 30 to 300 kgf/cm ² and a holding time of 10 to 90 minutes, and after crosslinking reaction and decomposition of the foaming agent, the mold is closed. A primary crosslinked foam is produced by opening and foaming the foam composition.
The shape of the mold for producing the primary crosslinked foam is not particularly limited, but can be any shape that allows a sheet to be obtained. This mold preferably has a completely sealed structure so that gas generated during melting of the resin, decomposition of the blowing agent, etc. does not escape to the outside. As the formwork, from the viewpoint of mold releasability of the resin, a formwork with a tapered inner surface is preferable.

In the foam manufacturing method of the present embodiment, the primary crosslinked foam may be given a predetermined shape by compression molding, if necessary. The compression molding conditions are not particularly limited, but from the viewpoint of the reaction rate of the crosslinking agent and blowing agent, the mold temperature is 120 to 200°C, the clamping pressure is 30 to 300 kgf/cm ² , the compression time is 5 to 60 minutes, Preferably, the compression ratio is in the range of 1.1 to 3.0.

When the foam obtained by the foam manufacturing method of the present embodiment is used particularly as a midsole, the foam preferably has a specific gravity of 0.08 to 0.25. Generally, reducing the specific gravity tends to cause a decrease in physical properties, such as a decrease in tear strength and an increase in permanent compressive strain, but the foam of this embodiment has an excellent balance of physical properties even at a low specific gravity. The specific gravity of the foam can be controlled by adjusting the amount of the foaming agent (E). (E) By increasing the foaming agent, the specific gravity after foaming can be lowered.

In the foam manufacturing method of the present embodiment, the foam composition can be molded into various shapes and sizes other than sheet shapes. In this embodiment, there is no particular restriction on the shape or size of the foam or the foam composition that constitutes the foam, and it can be molded into various shapes other than a sheet shape.

EXAMPLES Hereinafter, the present embodiment will be described in more detail with reference to Examples and Comparative Examples; however, the present invention is not limited to these Examples and Comparative Examples.
In Examples and Comparative Examples, foams were produced by the method described below, and the physical properties and characteristics were compared.
The physical properties of the conjugated diene copolymer and the physical properties and characteristics of the foam were measured as follows.

[Physical properties of conjugated diene copolymer]
(MFR)
The fluidity of the conjugated diene polymer was measured in accordance with ISO 1133.
Specifically, the melt flow rate (MFR) value at 230° C. and a load of 2.16 kg was measured.

[Physical properties and characteristics of foam]
((1) Specific gravity)
The secondary crosslinked foam was punched out into a test piece with a diameter of 1.4 cm and a thickness of 1 cm, and the specific gravity was measured using an electronic hydrometer (MD-200S manufactured by Aluminum Far Mirage).

((2) Resilience)
The rebound resilience of the secondary cross-linked foam was measured in accordance with JIS K6255, and when a 15 g iron ball was dropped from a height of 40 cm (=L0), the bounce height (=L) of the iron ball was determined at 23°C. It was measured using the following formula.
Repulsion elasticity (%) = (L/L0) x 100
A rebound resilience of 50% or more was judged to be practically good.

((3) split tear strength)
The secondary crosslinked foam was made into a test piece measuring 2 cm wide x 10 cm long x 1 cm thick. A 2 cm cut was made in the middle of the test piece in the longitudinal direction, and the test piece was sandwiched between chucks of about 4 cm, and the test piece was heated at a speed of 100 mm/min in the thickness direction. The tear strength was measured using a universal tensile compression tester (TG-5kN NMB manufactured by Minebea).
A tear strength of 1.7 kgf/cm was judged to be good for practical use.

((4) Dimensional stability against heat)
The primary crosslinked foam was used as a test piece of 10 cm x 20 cm x 1 cm thickness, and after being held at 70°C for 40 minutes, the length of the diagonal line of the test piece was measured after being left to stand for 1 hour, and the rate of change before and after heating was measured. The dimensional stability against heat was evaluated.
◎: Rate of change less than 1% ○: Rate of change 1% or more and less than 2.5% △: Rate of change 2.5% or more and less than 3.5% ×: 3.5% or more Dimensional stability against heat ◎, 〇, △ was judged to be good for practical use.

((5) Compression set)
A test piece was obtained by punching out a circle with a diameter of 2.6 cm from the foam, compressed to 50% thickness, held at 50 ° C for 6 hours, released the pressure, and after 1 hour, measured the thickness after standing still. The magnitude of the residual strain was measured and the compression set (%) was evaluated.

((6) C hardness)
The C hardness (ASKER C) of the foam was measured using an ASKER hardness meter (CL-150 ASKER C manufactured by Kobunshi Keiki Co., Ltd.), and the 3-second value was read. Then, the average value (arithmetic mean) of the five points was taken and determined as C hardness.

((7) Bali)
Cross-linking foaming was performed using a press mold, and the loss of the molded body was evaluated based on the amount of burrs that protruded from the mold of the resulting foam.
○: Equal to the foam made of EVA alone △: Slightly more than the foam made of EVA alone ×: More than the foam made of EVA alone

((8) Mixability: undissolved residue during rolling)
Mixability was evaluated by visually checking for undissolved resin after roll kneading for a certain period of time.
○: No undissolved material △: Melted but partially mixed poorly ×: Some undissolved material remains

[Materials used in Examples and Comparative Examples]
(A) conjugated diene copolymer, (B) ethylene/polar monomer copolymer, (C) ethylene polymer, (D) crosslinking agent, (E) blowing agent, ( F) Additives are shown below.

(Preparation of hydrogenation catalyst)
In the Examples and Comparative Examples described later, hydrogenation catalysts used when producing hydrogenated block copolymer compositions were prepared by the following method.
A reaction vessel equipped with a stirring device was purged with nitrogen, and 1 L of dried and purified cyclohexane was charged therein. Next, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. While thoroughly stirring this, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the mixture was allowed to react at room temperature for about 3 days. A hydrogenation catalyst was thus obtained.

((A) Conjugated diene copolymer)
(A1) Hydrogenated styrene-butadiene-styrene triblock copolymer Styrene content 10% by mass,
1,2-vinyl bond amount in 1,3-butadiene unit: 35% by mass,
Hydrogenation rate of double bond of 1,3-butadiene unit: 98%,
Peak top molecular weight 120,000 <Method for producing conjugated diene polymer A1>
Batch polymerization was carried out in the following manner using a stirring device and a jacketed tank reactor with an internal volume of 100 L.
First, 36 L of cyclohexane was charged into a reactor and the temperature was adjusted to 50°C. Then, n-butyllithium (hereinafter referred to as "total monomer") was added to 100 parts by mass of the total amount of butadiene monomer and styrene monomer (hereinafter referred to as "total monomers") charged into the reactor. (also referred to as "Bu-Li") and 0.35 parts by mass of N,N,N',N'-tetramethylethylenediamine (hereinafter also referred to as "TMEDA") per mole of Bu-Li. Mol added.
Next, 5.0 parts by mass of styrene was added over 5 minutes, and the reaction was continued for an additional 15 minutes (the temperature reached 65° C. due to the polymerization reaction). At this point, the polymer solution was sampled and the polymerization conversion rate of styrene was measured and found to be 100%.
Next, a cyclohexane solution (concentration: 40 parts by mass) containing 90.0 parts by mass of butadiene was continuously introduced into the reactor at a constant rate over 10 minutes, and then reacted for 10 minutes until the reaction temperature reached a maximum temperature of 86°C. After reaching this point, the reaction was continued for an additional 3 minutes. At this point, the polymer solution was sampled and the polymerization conversion rate of butadiene was measured and found to be 100%.
Next, 5.0 parts by mass of styrene was added over a period of 5 minutes, and the reaction was then continued for an additional 5 minutes.
Thereafter, 0.95 mol of methanol was added to 1 mol of Bu-Li to terminate the polymerization reaction and obtain a copolymer.
The hydrogenation catalyst was added to the obtained copolymer in an amount of 50 ppm as titanium per 100 parts by mass of the copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.9 MPa and a temperature of 90° C. for 45 minutes.
Thereafter, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate was added as a stabilizer to 100 parts by mass of the copolymer, and the conjugated diene copolymer was I got A1. The tan δ peak temperature measured by the dynamic viscoelasticity measurement described in this specification was −25° C. or lower.

<Method for producing conjugated diene polymers A2 to A31>
The block structure, styrene content, Bu-Li addition amount, and TMEDA addition amount shown in Tables 1 to 3 were used, and other conditions were the same as those for the conjugated diene polymer A1. The tan δ peak temperatures measured by the dynamic viscoelasticity measurement described in this specification were all −25° C. or lower.

Regarding the component (A) used in Examples and Comparative Examples, the above (A1) and (A2) to (A31) are shown in Tables 1 to 3 below.
In addition, in the "block structure" of component (A) shown in Tables 1 to 3, "a" is a polymer block mainly composed of styrene, and "b" is a polymer block mainly composed of butadiene. shall be.

The styrene content of component (A) was measured by proton nuclear magnetic resonance ( ¹ H-NMR) using a conjugated diene copolymer before hydrogenation. The measurement equipment was JNM-LA400 (manufactured by JEOL), deuterated chloroform was used as the solvent, sample concentration was 50 mg/mL, observation frequency was 400 MHz, tetramethylsilane was used as the chemical shift standard, pulse delay was 2.904 seconds, and scanning was performed. The measurement was carried out 64 times at a pulse width of 45° and a measurement temperature of 26°C. Styrene content was calculated using the integrated value of the total styrene aromatic signal from 6.2 to 7.5 ppm of the spectrum.

The amount of 1,2-vinyl bonds in the conjugated diene was measured by proton nuclear magnetic resonance ( ¹ H-NMR) using the conjugated diene copolymer before hydrogenation. The measurement conditions and the method of processing the measurement data were the same as the method for measuring the styrene content described above.
The amount of 1,2-vinyl bond is calculated by calculating the integral value per ¹ H of each bond type from the integral value of the signal attributed to 1,4-vinyl bond, 1,2-vinyl bond, and 3,4-vinyl bond. After that, it was calculated by (1,2-vinyl bond + 3,4-vinyl bond)/(1,2-vinyl bond + 3,4-vinyl bond + 1,4-vinyl bond).

The hydrogenation rate was measured by proton nuclear magnetic resonance ( ¹ H-NMR) using the hydrogenated conjugated diene copolymer. The measurement conditions and the method of processing the measurement data were the same as the method for measuring the styrene content described above.
The hydrogenation rate was determined by calculating the integral value of the signal originating from the residual double bond at 4.5 to 5.5 ppm and the signal originating from the hydrogenated conjugated diene, and calculating the ratio thereof.

The highest peak top molecular weight of the conjugated diene copolymer was measured by gel permeation chromatography (GPC) [apparatus: manufactured by Waters] under the following conditions. From the obtained chromatogram, the peak top molecular weight of the conjugated diene copolymer was determined using a calibration curve (created using the peak molecular weight of standard polystyrene) determined from measurements of commercially available standard polystyrene.
(Measurement condition)
GPC; ACQUITY APC system (manufactured by Nippon Waters Co., Ltd.)
System (measurement/analysis) software; Empower3
Detector: Differential refractive index (RI) detector Refractive index unit full scale: 500 μRIU
Output full scale: 2000mV
Sampling rate: 10 points/sec
Column; ACQUITY APC XT125 (4.6mm x 150mm); 1 column
ACQUITY APC XT200 (4.6mm x 150mm); 1 piece
ACQUITY APC XT900 (4.6mm x 150mm); 1 piece
ACQUITY APC XT450 (4.6mm x 150mm); 1 piece Solvent: Tetrahydrofuran (THF)
Flow rate: 1.0mL/min Concentration: 0.1mg/mL
Column temperature: 40℃
Injection volume: 20μL

((B) Ethylene/polar monomer copolymer)
(B1) Ethylene/vinyl acetate copolymer (manufactured by HANWHA, product name "EVA1317", VA content 22%)
(B2) Ethylene/vinyl acetate copolymer (manufactured by HANWHA, product name "EVA1315", VA content 15%)
(B3) Ethylene/ethyl acrylate copolymer (manufactured by Mitsui Dow Polychemicals, trade name "Elvaloy AC2615")

((C) Ethylene polymer)
(C1) Tafmer DF810 (manufactured by Mitsui Chemicals, ethylene/1-butene copolymer)
(C2) ENGAGE 8440 (manufactured by Dow, ethylene-octene copolymer)
(C3) INFUSE 9530 (manufactured by Dow, ethylene/octene block copolymer)

((D) Crosslinking agent)
Dicumyl peroxide (manufactured by NOF Corporation)

((E) Foaming agent)
CELLCOM-JTR (manufactured by KUMYANG), an ADCA-based organic pyrolytic blowing agent

((F) Additive)
(F1) Titanium dioxide (F2) Stearic acid (F3) Zinc oxide

[Example 1]
40 parts by mass of conjugated diene copolymer (A1), 60 parts by mass of ethylene/polar monomer copolymer (B1), 0.8 parts by mass of crosslinking agent (D), 5.0 parts by mass of blowing agent (E), addition After melt-kneading 4 parts by mass of additive (F1), 1 part by mass of additive (F2), and 5 parts by mass of additive (F3) using rolls set at 120°C, the mixture was heated at 160°C using a press mold at 100 kgf/ Crosslinking and foaming was performed at cm ² to obtain a primary crosslinked foam. The primary foam was evaluated for dimensional stability against heat.
A secondary crosslinked foam was obtained by compression molding this primary crosslinked foam to a specific gravity of 0.15.
Subsequently, the physical properties of this secondary crosslinked foam were measured by the method described above. C hardness was 47.

[Examples 2 to 36, Comparative Examples 1 to 7]
The compositions of Examples 2 to 36 and Comparative Examples 1 to 7 are shown in Tables 4 to 8.
A primary crosslinked foam and a secondary crosslinked foam were produced in the same manner as in Example 1, except for the changes as shown in Tables 4 to 8, and their physical properties and characteristics were measured.

Examples 1 to 36 exhibited an excellent performance balance in impact resilience, tear strength, and dimensional stability against heat.
From Example 1 and Examples 12 to 16, it was found that the amount of vinyl bonding affects the impact resilience and compression set, and as the amount of vinyl bonding increases, the impact resilience increases, but conversely, the compression set worsens. Furthermore, from Example 1 and Examples 4 to 7, it was found that the hydrogenation rate affected the tear strength, and that the higher the hydrogenation rate, the more the tear strength tended to improve. From the viewpoint of the durability of footwear, higher tear strength is preferred, and higher hydrogenation rates tend to be preferred.
On the other hand, in Comparative Examples 1 to 7, no good evaluation was obtained in terms of impact resilience, tear strength, or dimensional stability against heat in practical terms.

[Example 37]
20 parts by mass of conjugated diene copolymer (A1), 60 parts by mass of ethylene/polar monomer copolymer (B1), 20 parts by mass of ethylene polymer (C1), 0.8 parts by mass of crosslinking agent (D), foaming After melt-kneading 5.0 parts by mass of agent (E), 4 parts by mass of additive (F1), 1 part by mass of additive (F2), and 5 parts by mass of additive (F3) using rolls set at 120°C, Crosslinking and foaming was performed using a press mold at 160° C. and 100 kgf/cm ² to obtain a primary crosslinked foam. The dimensional stability against heat of the primary crosslinked foam was evaluated.
A secondary crosslinked foam was obtained by compression molding this primary crosslinked foam to a specific gravity of 0.15. Subsequently, the physical properties and characteristics of this secondary crosslinked foam were measured by the above method. C hardness was 47.

[Examples 38-70, Comparative Examples 8-13]
The compositions of Examples 38 to 70 and Comparative Examples 8 to 13 are shown in Tables 9 to 12 below.
A primary crosslinked foam and a secondary crosslinked foam were produced in the same manner as in Example 36, except for the changes shown in Tables 9 to 12, and their physical properties and characteristics were measured.

Examples 37 to 70 exhibited an excellent performance balance in impact resilience, tear strength, and dimensional stability against heat. Compared to Examples 1 to 36, by further blending the ethylene polymer (C), higher tear strength was exhibited while maintaining the performance balance.
On the other hand, in Comparative Examples 8 to 13, no good evaluation was obtained in terms of impact resilience, tear strength, or dimensional stability against heat in practical terms.

The foam composition and foam according to the present invention can be used in various molded products such as automobile parts, civil engineering/construction applications, home appliance parts, midsoles for shoes, sports goods, miscellaneous goods, stationery, and a wide variety of other products. It has industrial applicability in the field.

Claims (23)

(A) a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit;
(E) A foam composition comprising a foaming agent,
The content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass,
The hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100% by mass,
The content of the component (A) is 5 to 50 parts by mass relative to 100 parts by mass of the foamable polymer containing the component (A) in the foam composition.
Composition for foams. (B) an ethylene/polar monomer copolymer;
(D) a crosslinking agent;
A composition for a foam further comprising:
5 to 50 parts by mass of the component (A) and 50 parts by mass of the component (B) to 100 parts by mass of the foamable polymer containing the component (A) and the component (B) in the foam composition. Contains ~95 parts by mass,
The composition for foam according to claim 1. The amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of the component (A) is 10 to 60% by mass,
The composition for foam according to claim 1. The amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of the component (A) is 10 to 50% by mass,
The composition for foam according to claim 1. The amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of the component (A) is 15 to 50% by mass,
The composition for foam according to claim 1. The amount of 1,2-vinyl bonds and the amount of 3,4-vinyl bonds in the conjugated diene monomer unit of the component (A) is 25 to 50% by mass,
The composition for foam according to claim 1. The peak top molecular weight of the component (A) is 80,000 to 200,000,
The composition for foam according to claim 1. The peak top molecular weight of the component (A) is 100,000 to 150,000,
The composition for foam according to claim 1. The hydrogenation rate of the conjugated diene monomer unit of the component (A) is 50 to 100% by mass,
The composition for foam according to claim 1. The hydrogenation rate of the conjugated diene monomer unit of the component (A) is 70 to 100% by mass,
The composition for foam according to claim 1. The hydrogenation rate of the conjugated diene monomer unit of the component (A) is 95 to 100% by mass,
The composition for foam according to claim 1. The MFR (230° C., 2.16 kg) of the component (A) is 1.0 to 15 g/10 min.
The composition for foam according to claim 1. The vinyl aromatic monomer of the component (A) is styrene, the conjugated diene monomer is 1,3-butadiene,
The component (A) has a block structure of styrene block-1,3-butadiene block-styrene block,
The composition for foam according to claim 1. The tan δ peak temperature of the component (A) is -25°C or less,
The composition for foam according to claim 1. The content of the component (A) is
5 to 40 parts by mass based on 100 parts by mass of the foamable polymer,
The composition for foam according to claim 1. The content of the component (A) is
5 to 30 parts by mass based on 100 parts by mass of the foamable polymer,
The composition for foam according to claim 1. (C) further comprising an ethylene polymer,
The content of the component (C) is 45 parts by mass or less with respect to 100 parts by mass of the foamable polymer.
The composition for foam according to claim 1. The content of the component (C) is 5 to 40 parts by mass based on 100 parts by mass of the foamable polymer.
The foam composition according to claim 17. The content of the component (C) is 5 to 30 parts by mass based on 100 parts by mass of the foamable polymer.
The foam composition according to claim 17. (A) a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit; and (B) an ethylene/polar monomer copolymer having a crosslinked structure;
The content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass,
A foam in which the hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100% by mass,
In the foam, the (A) component is 5 to 50 parts by mass, and the (B) component is 50 to 95 parts by mass, relative to 100 parts by mass of the foamable polymer containing the (A) component and the (B) component. ,included,
foam. 21. The foam of claim 20, which is a midsole. (A) a conjugated diene copolymer containing a conjugated diene monomer unit and a vinyl aromatic monomer unit;
(B) an ethylene/polar monomer copolymer;
(D) a crosslinking agent;
(E) a foaming agent;
and the content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass,
A method for producing a foam using a foam composition, wherein the hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100% by mass,
In the foam composition, the content of the component (A) is 5 to 50 parts by mass, based on 100 parts by mass of the foamable polymer containing the components (A) and (B), and the content of the component (B) is 5 to 50 parts by mass. The content is 50 to 95 parts by mass,
Melting and kneading the foam composition to obtain a melt-kneaded product;
heating and/or irradiating the molten kneaded material with energy rays;
have,
Method of manufacturing foam. (A) a conjugated diene copolymer and/or hydrogenated product thereof containing a conjugated diene monomer unit and a vinyl aromatic monomer unit;
(B) an ethylene/polar monomer copolymer;
(D) a crosslinking agent;
and the content of vinyl aromatic monomer units in the component (A) is 5 to 15% by mass,
A method for producing a foam using a foam composition in which the hydrogenation rate of the conjugated diene monomer units in the component (A) is 30 to 100% by mass,
In the foam composition, the content of the component (A) is 5 to 50 parts by mass, based on 100 parts by mass of the foamable polymer containing the component (A) and the component (B). The content of is 50 to 95 parts by mass,
kneading the foam composition to obtain a kneaded product;
a step of molding and crosslinking the kneaded material to obtain a crosslinked molded product;
(E) impregnating the crosslinked molded body with a foaming agent, and then foaming it by reducing the pressure;
have,
Method of manufacturing foam.