Crosslinkable polymer composition, crosslinked product, and crosslinked foam

Abstract

Provided is a crosslinkable polymer composition comprising a hydrogenated block copolymer (A) represented by general formula (A) and a hydrogenated block copolymer (B) represented by general formula (B) in a specific weight ratio (A / B), containing a hydrogenated block copolymer composition having an olefin hydrogenation rate of 10-100% and a polyolefin thermoplastic resin (C) in a specific ratio (C / (A + B)), and further containing a crosslinking agent.

Description

Technical Field

[0001] The present invention relates to a crosslinkable polymer composition, and more particularly to a crosslinkable polymer composition having excellent moldability and capable of forming a crosslinked product having a good balance between high rebound resilience and compression set resistance. Background Art

[0002] Aromatic vinyl-conjugated diene-aromatic vinyl block copolymers such as styrene-isoprene-styrene block copolymer (SIS) and styrene-butadiene-styrene block copolymer (SBS) are thermoplastic elastomers having characteristic properties in various aspects and are therefore used in a variety of applications.

[0003] For example, Patent Document 1 discloses a crosslinked foaming composition, which comprises (A) an ethylene copolymer, (B) a vinyl aromatic copolymer comprising a vinyl aromatic monomer unit and a conjugated diene monomer unit having an unsaturated bond, (C) an organic peroxide, and (D) a foaming agent, wherein the mass ratio (A / B) of the component (A) to the component (B) is 97 / 3 to 50 / 50, and the component (B) comprises 5% by mass or more and 80% by mass or less of the vinyl aromatic monomer unit, and 5% to 55% by mass of the conjugated diene monomer unit. However, the technology of Patent Document 1 fails to take into account both the high resilience and the compression set resistance of the obtained crosslinked product.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent document 1: International Publication No. 2010 / 073589. Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The present invention has been made in view of such actual circumstances, and an object of the present invention is to provide a cross-linkable polymer composition which has excellent moldability and can form a cross-linked product having a good balance between high rebound resilience and compression set resistance.

[0009] Solutions for solving problems

[0010] The present inventors have conducted studies to achieve the above-mentioned object and have found that the above-mentioned object can be achieved by a crosslinkable polymer composition comprising a hydrogenated block copolymer A represented by the general formula (A) and a hydrogenated block copolymer B represented by the general formula (B) at a specific weight ratio (A / B), a hydrogenated block copolymer composition having an olefin hydrogenation rate of 10 to 100% and a polyolefin-based thermoplastic resin C at a specific ratio (C / (A+B)), and a crosslinking agent, thereby completing the present invention.

[0011] That is, according to the present invention, the following cross-linkable polymer composition can be provided.

[0012] [1] A cross-linkable polymer composition comprising:

[0013] A hydrogenated block copolymer composition comprising a hydrogenated block copolymer A represented by the following general formula (A) and a hydrogenated block copolymer B represented by the following general formula (B);

[0014] Polyolefin-based thermoplastic resin C; and

[0015] Crosslinking agent,

[0016] The hydrogenation rate of olefins in the polymer components constituting the hydrogenated block copolymer composition is 10 to 100%,

[0017] The weight ratio (A / B) of the hydrogenated block copolymer A to the hydrogenated block copolymer B in the hydrogenated block copolymer composition is 10 / 90 to 80 / 20.

[0018] The ratio of the content of the polyolefin-based thermoplastic resin C to the total content of the hydrogenated block copolymer A and the hydrogenated block copolymer B (C / (A+B)) is 5 / 95 to 80 / 20 by weight.

[0019] .

[0020] In the above general formula (A) and general formula (B), Ar1 a 、Ar2 a 、Ar1 b and Ar2 b Aromatic vinyl polymer block, HD a and HD b is a hydrogenated polymer block of a conjugated diene polymer, Ar2 a The weight average molecular weight (Mw(Ar2 a ))Relative to Ar1 a The weight average molecular weight (Mw(Ar1 a )) ratio (Mw(Ar2 a ) / Mw(Ar1 a)) is 3.0~20, Ar2 b The weight average molecular weight (Mw(Ar2 b ))Relative to Ar1 b The weight average molecular weight (Mw(Ar1 b )) ratio (Mw(Ar2 b ) / Mw(Ar1 b )) is 0.95~1.05.

[0021] [2] The cross-linkable polymer composition according to [1], wherein the ratio of the aromatic vinyl monomer unit in all repeating units of the polymer component of the hydrogenated block copolymer composition is 20 to 70% by weight.

[0022] [3] The cross-linkable polymer composition according to [1] or [2], wherein HD in the general formula (A) and the general formula (B) of the hydrogenated block copolymer composition is a and HD b The vinyl bond content of each is 1 to 80 mol %.

[0023] [4] The cross-linkable polymer composition according to any one of [1] to [3], wherein Ar1 in the general formula (A) and the general formula (B) of the hydrogenated block copolymer composition is a 、Ar1 b and Ar2 b The weight average molecular weight of HD a and HD b The weight average molecular weight is in the range of 10,000 to 300,000.

[0024] [5] The cross-linkable polymer composition according to any one of [1] to [4], wherein the weight average molecular weight of all polymer components constituting the hydrogenated block copolymer composition is 30,000 to 400,000.

[0025] [6] The cross-linkable polymer composition according to any one of [1] to [5], wherein the polyolefin-based thermoplastic resin C is an ethylene-based resin.

[0026] [7] The cross-linkable polymer composition according to any one of [1] to [6], wherein the ratio of the content of the polyolefin-based thermoplastic resin C to the total content of the hydrogenated block copolymer A and the hydrogenated block copolymer B (C / (A+B)) is 15 / 85 to 50 / 50 by weight.

[0027] [8] The cross-linkable polymer composition according to any one of [1] to [7], further comprising a foaming agent.

[0028] [9] The cross-linkable polymer composition according to [8], wherein the foaming agent is a chemical foaming agent.

[0029] Furthermore, according to the present invention, the following cross-linked products and cross-linked foams can be provided.

[0030]

[10] A cross-linked product obtained by cross-linking the cross-linkable polymer composition according to any one of [1] to [9].

[0031]

[11] A cross-linked foam obtained by cross-linking and foaming the cross-linkable polymer composition according to any one of [1] to [9].

[0032]

[12] The cross-linked foam according to

[11] , wherein the cross-linked foam is a midsole of a shoe.

[0033]

[13] The cross-linked foam according to

[11] , wherein the cross-linked foam is a buffer material for a battery.

[0034]

[14] The cross-linked foam according to

[11] , wherein the cross-linked foam is a weatherstrip.

[0035]

[15] The cross-linked foam according to any one of

[11] to

[14] , wherein the apparent density of the cross-linked foam is 0.06 to 0.60 g / cm 3 .

[0036] Effects of the Invention

[0037] According to the present invention, there can be provided a cross-linkable polymer composition which has excellent moldability and can form a cross-linked product having a good balance between high rebound resilience and compression set resistance. DETAILED DESCRIPTION

[0038] The crosslinkable polymer composition of the present invention contains the hydrogenated block copolymer composition described below, a polyolefin-based thermoplastic resin C, and a crosslinking agent.

[0039] The crosslinkable polymer composition of the present invention has sufficient crosslinking properties, so the effect of crosslinking can be fully obtained. Furthermore, it is believed that the crosslinkable polymer composition of the present invention contains a hydrogenated block copolymer composition having a specific structure and a polyolefin-based thermoplastic resin C as polymer components at a specific ratio, which can make the obtained crosslinked product excellent in strain hardening. Such a crosslinkable polymer composition of the present invention can form a crosslinked product with a good balance between high resilience and compression set resistance.

[0040] In addition, according to the present invention, sufficient crosslinking and excellent strain hardening can be obtained, thus it is possible to suppress the poor molding when the crosslinkable polymer composition of the present invention is crosslinked or when it is molded after crosslinking, and as a result, it is also possible to mold (for example, with high stretch ratio, high foaming ratio molding) while a large deformation of the load is applied. In addition, about the manufacture of crosslinked foam, the crosslinkable polymer composition of the present invention can effectively suppress the bubbles from the crosslinkable polymer composition when crosslinking and foaming, so it is not only possible to foam with a high foaming ratio, but also possible to form a crosslinked foam with excellent uniformity. Like this, the crosslinkable polymer composition of the present invention can be applicable to various molding methods such as stretch molding and foam molding and excellent moldability.

[0041] [Hydrogenated block copolymer composition]

[0042] The hydrogenated block copolymer composition contained in the crosslinkable polymer composition of the present invention comprises a hydrogenated block copolymer A represented by the following general formula (A) and a hydrogenated block copolymer B represented by the following general formula (B), the hydrogenation rate of olefins in the polymer components constituting the hydrogenated block copolymer composition is 10 to 100%, and the weight ratio (A / B) of the hydrogenated block copolymer A to the hydrogenated block copolymer B in the hydrogenated block copolymer composition is 10 / 90 to 80 / 20.

[0043] .

[0044] (In the above general formula (A) and general formula (B), Ar1 a 、Ar2 a 、Ar1 b and Ar2 b Aromatic vinyl polymer block, HD a and HD b is a hydrogenated polymer block of a conjugated diene polymer, Ar2 a The weight average molecular weight (Mw(Ar2 a ))Relative to Ar1 a The weight average molecular weight (Mw(Ar1 a )) ratio (Mw(Ar2 a ) / Mw(Ar1 a )) is 3.0~20, Ar2 b The weight average molecular weight (Mw(Ar2 b ))Relative to Ar1 b The weight average molecular weight (Mw(Ar1 b )) ratio (Mw(Ar2 b ) / Mw(Ar1 b )) is 0.95~1.05).

[0045] The hydrogenated block copolymer composition used in the present invention is not particularly limited, but preferably contains only the hydrogenated block copolymer A and the hydrogenated block copolymer B as polymer components.

[0046] Aromatic vinyl polymer blocks Ar1 of hydrogenated block copolymer A and hydrogenated block copolymer B a 、Ar2 a 、Ar1 b 、Ar2 b It is a polymer block composed of aromatic vinyl monomer units.

[0047] As an aromatic vinyl monomer for constituting an aromatic vinyl monomer unit, there is no particular limitation as long as it is an aromatic vinyl compound. As an aromatic vinyl compound, for example, styrene; α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene and other alkyl-substituted styrenes; 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibromostyrene and other halogen-substituted styrenes; vinylnaphthalene, etc. Among these, styrene is preferably used. These aromatic vinyl monomers can be used alone or in combination of two or more in each aromatic vinyl polymer block. In addition, in each aromatic vinyl polymer block, the same aromatic vinyl monomer can be used, or different aromatic vinyl monomers can be used. The content of the aromatic vinyl monomer unit in each aromatic vinyl polymer block is preferably 80% by weight or more, more preferably 90% by weight or more, and particularly preferably substantially 100% by weight, based on the entire aromatic vinyl polymer block.

[0048] In addition, the aromatic vinyl polymer blocks Ar1 constituting the hydrogenated block copolymer A and the hydrogenated block copolymer B are a 、Ar2 a 、Ar1 b 、Ar2 b The monomer units other than the aromatic vinyl monomer units may be included. Examples of monomer units other than the aromatic vinyl monomer units include conjugated diene monomers such as 1,3-butadiene and isoprene (2-methyl-1,3-butadiene); α,β-unsaturated nitrile monomers; unsaturated carboxylic acid or anhydride monomers; unsaturated carboxylic acid ester monomers; and non-conjugated diene monomers.

[0049] The content of monomer units other than aromatic vinyl monomer units in each aromatic vinyl polymer block is preferably 20 wt % or less, more preferably 10 wt % or less, and particularly preferably substantially 0 wt % based on the entire aromatic vinyl polymer block.

[0050] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A and the hydrogenated block copolymer B a , HD b The polymer block is composed of conjugated diene monomer units, and at least a part of the conjugated diene monomer units constituting the polymer block is hydrogenated.

[0051] As the conjugated diene monomer for constituting the conjugated diene monomer unit, as long as it is a conjugated diene compound, there is no particular limitation. As the conjugated diene compound, for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc. can be cited. Among these, from the viewpoint of polymerization reactivity, 1,3-butadiene and / or isoprene are preferably used, and isoprene is particularly preferably used. These conjugated diene monomers can be used alone or in combination of two or more in each hydrogenated polymer block. In addition, in each hydrogenated polymer block, the same conjugated diene monomer can be used, and different conjugated diene monomers can also be used. The content of the conjugated diene monomer units (including hydrogenated conjugated diene monomer units) in each hydrogenated polymer block is preferably 80 wt % or more, more preferably 90 wt % or more, particularly preferably substantially 100 wt % based on the entire conjugated diene polymer block.

[0052] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A and the hydrogenated block copolymer B a , HD b The monomer units other than the conjugated diene monomer units may be included. Examples of monomer units other than the conjugated diene monomer units include aromatic vinyl monomers such as styrene and α-methylstyrene; α,β-unsaturated nitrile monomers; unsaturated carboxylic acid or anhydride monomers; unsaturated carboxylic acid ester monomers; and non-conjugated diene monomers.

[0053] The content of monomer units other than conjugated diene monomer units (including hydrogenated conjugated diene monomer units) in each hydrogenated polymer block is preferably 20 wt % or less, more preferably 10 wt % or less, and particularly preferably substantially 0 wt % based on the entire conjugated diene polymer block.

[0054] Ar2 of the hydrogenated block copolymer A constituting the hydrogenated block copolymer composition a The weight average molecular weight (Mw(Ar2a ))Relative to Ar1 a The weight average molecular weight (Mw(Ar1 a )) ratio (Mw(Ar2 a ) / Mw(Ar1 a )) is in the range of 3.0 to 20. Therefore, the hydrogenated block copolymer A is an aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight. a , hydrogenated polymer block HD of conjugated diene polymer a and an aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight a A hydrogenated product of an asymmetric aromatic vinyl-conjugated diene-aromatic vinyl block copolymer composed of sequentially connected blocks.

[0055] In the hydrogenated block copolymer A, Mw(Ar2 a ) / Mw(Ar1 a ) is in the range of 3.0 to 20. Regardless of Mw(Ar2 a ) / Mw(Ar1 a ) is too small or too large, it is difficult to take into account both the high resilience and compression set resistance of the obtained cross-linked product. a ) / Mw(Ar1 a ) is preferably in the range of 4.0 to 16, and more preferably in the range of 5.0 to 13. a ) / Mw(Ar1 a ) in the above range, the moldability can be further improved, and the high resilience and compression set resistance of the obtained cross-linked product can be taken into account at a higher level. In addition, in the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer and polymer block are measured by high performance liquid chromatography and obtained as polystyrene-converted values.

[0056] In addition, the aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight constituting the hydrogenated block copolymer A a The weight average molecular weight (Mw(Ar1 a )) is preferably 2000 to 40000, more preferably 2500 to 15000, and still more preferably 3000 to 8000. a ) within the above range, the moldability can be further improved, and the high resilience and compression set resistance of the obtained cross-linked product can be achieved at a higher level while also improving the mechanical properties.

[0057] In addition, the aromatic vinyl polymer block Ar2 having a large weight average molecular weight constituting the hydrogenated block copolymer A a The weight average molecular weight (Mw(Ar2a )) is preferably 5000 to 250000, more preferably 10000 to 120000, and still more preferably 20000 to 80000. a ) within the above range, the moldability can be further improved, and the high resilience and compression set resistance of the obtained cross-linked product can be achieved at a higher level while also improving the mechanical properties.

[0058] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A a The vinyl bond content (the proportion of 1,2-vinyl bonds and 3,4-vinyl bonds in all conjugated diene monomer units) is preferably 1 to 80 mol%, more preferably 3 to 20 mol%, and further preferably 5 to 12 mol%. By making the vinyl bond content within the above range, it is possible to achieve both high resilience and compression set resistance of the resulting cross-linked product at a higher level. The vinyl bond content of the hydrogenated polymer block of the conjugated diene polymer can be increased by using deuterated chloroform as a solvent. 1 It can be determined by H-NMR.

[0059] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A a The weight average molecular weight (Mw(HD a )) is preferably 10,000 to 300,000, more preferably 15,000 to 300,000, further preferably 15,000 to 150,000, particularly preferably 20,000 to 80,000.

[0060] The content of the aromatic vinyl monomer unit relative to the total monomer units of the hydrogenated block copolymer A is not particularly limited, but is preferably 30 to 95% by weight, more preferably 35 to 90% by weight, further preferably 40 to 87% by weight, and particularly preferably 45 to 85% by weight. The content of the aromatic vinyl monomer unit relative to the total monomer units of the hydrogenated block copolymer A can be determined based on the detection intensity ratio of the differential refractometer and the ultraviolet detector in the measurement of the high performance liquid chromatograph.

[0061] The weight average molecular weight of the hydrogenated block copolymer A as a whole is not particularly limited, but is preferably 20,000 to 500,000, more preferably 25,000 to 300,000, and even more preferably 30,000 to 150,000.

[0062] In addition, the hydrogenated block copolymer B constituting the hydrogenated block copolymer composition is a conjugated diene polymer block HD b Two aromatic vinyl polymer blocks Ar1 are bonded to both ends of b 、Ar2 bThe hydrogenated product of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer is formed. b 、Ar2 b The weight average molecular weight (Mw(Ar1 b )、Mw(Ar2 b )), Ar2 b The weight average molecular weight (Mw(Ar2 b ))Relative to Ar1 b The weight average molecular weight (Mw(Ar1 b )) ratio (Mw(Ar2 b ) / Mw(Ar1 b )) is 0.95~1.05.

[0063] The two aromatic vinyl polymer blocks Ar1 constituting the hydrogenated block copolymer B b 、Ar2 b The weight average molecular weight (Mw(Ar1 b )、Mw(Ar2 b )) are preferably 2000 to 40000, more preferably 2500 to 15000, and still more preferably 3000 to 8000. b ) and Mw(Ar2 b ) within the above range, the moldability can be further improved, and the high resilience and compression set resistance of the obtained cross-linked product can be taken into account at a higher level while also improving the mechanical properties. The two aromatic vinyl polymer blocks Ar1 b 、Ar2 b The weight average molecular weight (Mw(Ar1 b )、Mw(Ar2 b )) may be equal to each other or unequal to each other, but are preferably substantially equal. For example, as long as Ar2 b The weight average molecular weight (Mw(Ar2 b ))Relative to Ar1 b The weight average molecular weight (Mw(Ar1 b )) ratio (Mw(Ar2 b ) / Mw(Ar1 b )) may be in the range of 0.95 to 1.05, preferably in the range of 0.97 to 1.03.

[0064] In addition, the two aromatic vinyl polymer blocks Ar1 b 、Ar2 b The weight average molecular weight (Mw(Ar1) of at least one polymer block in b )、Mw(Ar2 b)) can be combined with the aromatic vinyl polymer block Ar1 having a smaller weight average molecular weight constituting the hydrogenated block copolymer A a The weight average molecular weight (Mw(Ar1 a )) are equal, or they may not be equal, but they are more preferably substantially equal. For example, Ar1 b The weight average molecular weight (Mw(Ar1 b ))Relative to Ar1 a The weight average molecular weight (Mw(Ar1 a )) ratio (Mw(Ar1 b ) / Mw(Ar1 a )) can be in the range of 0.9 to 2.2, Ar2 b The weight average molecular weight (Mw(Ar2 b ))Relative to Ar1 a The weight average molecular weight (Mw(Ar1 a )) ratio (Mw(Ar2 b ) / Mw(Ar1 a )) may also be in the range of 0.9 to 2.2. In addition, for example, preferably Ar1 b The weight average molecular weight (Mw(Ar1 b ))Relative to Ar1 a The weight average molecular weight (Mw(Ar1 a )) ratio (Mw(Ar1 b ) / Mw(Ar1 a )) in the range of 0.95 to 1.05, or Ar2 b The weight average molecular weight (Mw(Ar2 b ))Relative to Ar1 a The weight average molecular weight (Mw(Ar1 a )) ratio (Mw(Ar2 b ) / Mw(Ar1 a )) is in the range of 0.95~1.05.

[0065] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B b The vinyl bond content (the proportion of 1,2-vinyl bonds and 3,4-vinyl bonds in all conjugated diene monomer units) is preferably 1 to 80 mol%, more preferably 3 to 20 mol%, and further preferably 5 to 12 mol%. By making the vinyl bond content within the above range, it is possible to achieve both high resilience and compression set resistance of the resulting cross-linked product at a higher level. The vinyl bond content of the hydrogenated polymer block of the conjugated diene polymer can be increased by using deuterated chloroform as a solvent. 1In addition, the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B is preferably b The vinyl bond content of the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A is a For example, the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B is preferably b The vinyl bond content of the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer A is a The ratio of the vinyl bond content is in the range of 0.95 to 1.05.

[0066] When the hydrogenated block copolymer composition used in the present invention is produced, when a production method using a coupling agent is used, such as the production method of the hydrogenated block copolymer composition having steps (1a) to (6a) described later, the hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B is b The residue of a coupling agent may be contained. Specifically, the hydrogenated block copolymer B may be a compound represented by the following formula.

[0067] .

[0068] That is, as shown in the above formula, the hydrogenated polymer block HD of the conjugated diene polymer b Can be HD b ', HD b ''A form in which the coupling is achieved via a coupling agent residue X. Examples of the coupling agent residue X include residues of bifunctional coupling agents exemplified in the method for producing a hydrogenated block copolymer composition having steps (1a) to (6a) described later.

[0069] The hydrogenated polymer block HD of the conjugated diene polymer constituting the hydrogenated block copolymer B b The weight average molecular weight (Mw(HD b )) is preferably 10,000 to 300,000, more preferably 15,000 to 300,000, further preferably 15,000 to 150,000, particularly preferably 20,000 to 80,000.

[0070] The content of the aromatic vinyl monomer unit relative to the total monomer units of the hydrogenated block copolymer B is not particularly limited, but is preferably 10 to 60% by weight, more preferably 15 to 40% by weight, and further preferably 20 to 35% by weight. The content of the aromatic vinyl monomer unit relative to the total monomer units of the hydrogenated block copolymer A can be determined based on the detection intensity ratio of the differential refractometer and the ultraviolet detector in the measurement of the high performance liquid chromatograph.

[0071] The weight average molecular weight of the hydrogenated block copolymer B as a whole is not particularly limited, but is preferably 20,000 to 200,000, more preferably 25,000 to 150,000, and even more preferably 30,000 to 70,000.

[0072] The molecular weight distribution represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) [(Mw) / (Mn)] of the hydrogenated block copolymer A and the hydrogenated block copolymer B constituting the hydrogenated block copolymer composition used in the present invention, and each polymer block constituting them is not particularly limited, but is preferably 1.1 or less, and more preferably 1.05 or less.

[0073] The weight ratio (A / B) of the hydrogenated block copolymer A and the hydrogenated block copolymer B contained in the hydrogenated block copolymer composition used in the present invention is 10 / 90 to 80 / 20. Whether the weight ratio (A / B) is too small or too large, it is difficult to take into account the high resilience and compression set resistance of the obtained cross-linked product. The weight ratio (A / B) is preferably 20 / 80 to 60 / 40, and more preferably 25 / 75 to 50 / 50. By containing hydrogenated block copolymer A and hydrogenated block copolymer B in such a ratio, the moldability can be further improved, and the high resilience and compression set resistance of the obtained cross-linked product can be taken into account at a higher level. The weight ratio (A / B) of hydrogenated block copolymer A and hydrogenated block copolymer B can be obtained based on the area ratio of the peaks corresponding to each block copolymer in the chart obtained by high performance liquid chromatography.

[0074] In addition, regarding the hydrogenated block copolymer composition used in the present invention, the hydrogenation rate of olefins in the polymer components constituting the hydrogenated block copolymer composition is in the range of 10 to 100%. Here, the hydrogenation rate of olefins refers to the hydrogenation rate of olefins in all polymer components constituting the hydrogenated block copolymer composition, and specifically refers to the proportion (mol %) of hydrogenated double bonds in all non-aromatic carbon-carbon double bonds contained in the polymer components before hydrogenation. If the hydrogenation rate of olefins is too low, it is difficult to achieve both high resilience and compression set resistance of the obtained cross-linked product, and further, poor molding is likely to occur in the case of molding simultaneously with cross-linking or molding after cross-linking. The hydrogenation rate of olefins is preferably 80 to 100%, more preferably 90 to 100%, and further preferably 95 to 100%. By making the hydrogenation rate of olefins within the above range, the effect brought about by cross-linking can be further improved, and a cross-linked product having excellent mechanical properties and dimensional stability in addition to high resilience and compression set resistance can be formed with high moldability and high productivity. The hydrogenation rate of olefins can be increased by using deuterated chloroform as a solvent. 1 It can be determined by H-NMR spectroscopy.

[0075] In the hydrogenated block copolymer composition used in the present invention, the proportion of the aromatic vinyl monomer unit relative to the total polymer components in the hydrogenated block copolymer composition (all monomer units constituting the polymer components) (hereinafter sometimes referred to as the "total aromatic vinyl monomer unit content") is preferably 20 to 70% by weight, more preferably 25 to 60% by weight, and further preferably 30 to 55% by weight. By making the total aromatic vinyl monomer unit content within the above range, the moldability can be further improved, and the high resilience and compression set resistance of the obtained cross-linked product can be achieved at a higher level while also improving the mechanical properties. The total aromatic vinyl monomer unit content can be easily adjusted by considering the content of the aromatic vinyl monomer units of the hydrogenated block copolymer A, hydrogenated block copolymer B, and polymer components other than them that constitute the hydrogenated block copolymer composition and adjusting their blending amounts. The total aromatic vinyl monomer unit content can be easily adjusted by using deuterated chloroform as a solvent. 1 It can be determined by H-NMR measurement.

[0076] In addition, when all polymer components constituting the hydrogenated block copolymer composition are composed only of aromatic vinyl monomer units and conjugated diene monomer units, the polymer components in the hydrogenated block copolymer composition are subjected to ozone decomposition according to the method described in Rubber Chem. Technol., 45, 1295 (1972), and then reduced using lithium aluminum hydride, thereby decomposing the conjugated diene monomer unit portion (including the hydrogenated portion), and only the aromatic vinyl monomer unit portion can be extracted, so the overall aromatic vinyl monomer unit content can be easily determined. The aromatic vinyl monomer unit content and the conjugated diene monomer unit content in each block copolymer can be obtained by the same method.

[0077] The weight average molecular weight of the total polymer components constituting the hydrogenated block copolymer composition used in the present invention is not particularly limited, but is preferably 30000 to 400000, more preferably 35000 to 100000, and even more preferably 40000 to 80000. When the weight average molecular weight of the total polymer components is within the above range, the moldability can be further improved, and the high resilience and compression set resistance of the obtained cross-linked product can be achieved at a higher level while also improving the mechanical properties.

[0078] The molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the entire polymer components constituting the hydrogenated block copolymer composition used in the present invention is not particularly limited, but is preferably 1 to 5, more preferably 1.01 to 3, and further preferably 1.02 to 1.5.

[0079] [Method for producing hydrogenated block copolymer composition]

[0080] The method for producing the hydrogenated block copolymer composition used in the present invention is not particularly limited, and the hydrogenated block copolymer A and the hydrogenated block copolymer B can be produced separately according to conventional block copolymer production methods and hydrogenation methods, and other polymer components and various additives can be added as needed, and then they can be mixed according to conventional methods such as kneading and solution mixing. On the other hand, in the present invention, the production method described below is preferred from the viewpoint of being able to produce the hydrogenated block copolymer composition with high productivity.

[0081] That is, the method for producing the hydrogenated block copolymer composition used in the present invention is preferably a method comprising the following steps (1) to (7).

[0082] (1): A step of polymerizing an aromatic vinyl monomer in a solvent using a polymerization initiator to obtain a solution containing an aromatic vinyl polymer having an active terminal;

[0083] (2) a step of adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having an active terminal obtained in the step (1) above to polymerize the conjugated diene monomer to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having an active terminal;

[0084] (3) a step of adding an aromatic vinyl monomer to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active terminal obtained in the step (2) above, and polymerizing the aromatic vinyl monomer to thereby obtain a solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active terminal;

[0085] (4) a step of adding a polymerization terminator in an amount less than 1 molar equivalent relative to the active ends to the solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active ends obtained in the above step (3) to deactivate a part of the active ends of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active ends, thereby obtaining a solution containing block copolymer B';

[0086] (5): A step of adding an aromatic vinyl monomer to the solution containing the block copolymer B' obtained in the above step (4) to polymerize the aromatic vinyl monomer to obtain a solution containing the block copolymer B' and the block copolymer A';

[0087] (6): A step of subjecting the solution containing the block copolymer B' and the block copolymer A' obtained in the step (5) to a hydrogenation reaction to obtain a solution containing the hydrogenated block copolymer B and the hydrogenated block copolymer A;

[0088] (7): A step of recovering a hydrogenated block copolymer composition from the solution containing the hydrogenated block copolymer B and the hydrogenated block copolymer A obtained in the step (6).

[0089] <Process (1)>

[0090] In the method for producing the hydrogenated block copolymer composition, first, in step (1), an aromatic vinyl monomer is polymerized in a solvent using a polymerization initiator to obtain a solution containing an aromatic vinyl polymer having an active terminal.

[0091] As the polymerization initiator, a polymerization initiator known to have anionic polymerization activity for aromatic vinyl monomers and conjugated diene monomers can be used. Examples of the polymerization initiator include organic alkali metal compounds, organic alkaline earth metal compounds, and organic lanthanide rare earth metal compounds.

[0092] As the organic alkali metal compound, it is particularly preferred to use an organic lithium compound having one or more lithium atoms in the molecule. Specific examples of the organic alkali metal compound include: organic monolithium compounds such as ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, hexyl lithium, phenyl lithium, distyrene lithium, dialkyl lithium amide, diphenyl lithium amide, bistrimethylsilyl lithium amide; organic dilithium compounds such as methylene dilithium, tetramethylene dilithium, hexamethylene dilithium, isoprenyl dilithium, 1,4-dilithium-ethylcyclohexane; and organic trilithium compounds such as 1,3,5-trilithium benzene. Among these, it is particularly preferred to use organic monolithium compounds.

[0093] Examples of the organic alkaline earth metal compound include n-butylmagnesium bromide, n-hexylmagnesium bromide, calcium ethoxide, calcium stearate, tert-butoxystrontium, barium ethoxide, isopropoxybarium, ethylmercaptobarium, tert-butoxybarium, phenoxybarium, diethylaminobarium, barium stearate, and ethylbarium.

[0094] In addition to the above, it is also possible to use: composite catalysts formed by lanthanum rare earth metal compounds containing neodymium, samarium, gadolinium, etc. / alkyl aluminum / alkyl aluminum halide / alkyl aluminum hydride, metallocene catalysts containing titanium, vanadium, samarium, gadolinium, etc., which are uniform systems in organic solvents and have active polymerization properties, etc.

[0095] The above-mentioned polymerization initiator can be used alone or in combination of two or more. The amount of the polymerization initiator used is not particularly limited as long as it is determined according to the molecular weight of each block copolymer as the target, and is preferably 0.01 to 20 millimoles, more preferably 0.05 to 15 millimoles, and further preferably 0.1 to 10 millimoles relative to 100 g of all monomers used for polymerization.

[0096] The solvent used for the polymerization is not particularly limited as long as it is an inactive solvent with respect to the polymerization initiator, and examples thereof include chain hydrocarbon solvents, cyclic hydrocarbon solvents, and mixed solvents thereof. Examples of chain hydrocarbon solvents include chain alkanes and alkenes having 4 to 6 carbon atoms, such as n-butane, isobutane, 1-butene, isobutylene, trans-2-butene, cis-2-butene, 1-pentene, trans-2-pentene, cis-2-pentene, n-pentane, isopentane, neopentane, and n-hexane. In addition, examples of cyclic hydrocarbon solvents include aromatic compounds such as benzene, toluene, and xylene; and alicyclic hydrocarbon compounds such as cyclopentane and cyclohexane. These solvents may be used alone or in combination of two or more.

[0097] The amount of the solvent used is not particularly limited, but is preferably an amount such that the concentration of the total block copolymers in the solution after the polymerization reaction becomes 5 to 60% by weight, more preferably an amount such that the concentration of the total block copolymers in the solution after the polymerization reaction becomes 10 to 55% by weight, and further preferably an amount such that the concentration of the total block copolymers in the solution after the polymerization reaction becomes 20 to 50% by weight.

[0098] In addition, when manufacturing the hydrogenated block copolymer composition, in order to control the structure of each polymer block of each block copolymer, a Lewis base compound can also be added to the reaction system. As Lewis base compounds, ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, and diethylene glycol dibutyl ether can be cited; tertiary amines such as tetramethylethylenediamine, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alcoholates such as potassium tert-amylate and potassium tert-butoxide; phosphines such as triphenylphosphine, etc. These Lewis base compounds can be used alone or in combination of two or more.

[0099] When manufacturing the hydrogenated block copolymer composition, the timing of adding the Lewis base compound is not particularly limited, as long as it is appropriately determined according to the structure of each block copolymer as the target. For example, it can be added in advance before initiating polymerization, or it can be added after a part of the polymer block is polymerized. Furthermore, it can also be added in advance before initiating polymerization, and further added after a part of the polymer block is polymerized.

[0100] The polymerization reaction temperature is preferably 10 to 150° C., more preferably 30 to 130° C., and further preferably 40 to 90° C. The polymerization time is preferably within 48 hours, and more preferably 0.5 to 10 hours. In addition, the polymerization pressure is not particularly limited as long as it is within the range of pressure sufficient to maintain the monomer and the solvent in a liquid phase at the polymerization temperature.

[0101] A solution containing an aromatic vinyl polymer having an active terminal can be obtained by polymerizing an aromatic vinyl monomer in a solvent using a polymerization initiator under the above conditions. As described above, the aromatic vinyl polymer having an active terminal obtained in step (1) constitutes the aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight of the hydrogenated block copolymer A constituting the hydrogenated block copolymer composition. a , and the aromatic vinyl polymer block Ar1 of the hydrogenated block copolymer B b 、Ar2 b Any one of (i.e. Ar1 b or Ar2 b Therefore, the polymerization conditions including the amount of the aromatic vinyl monomer in step (1) may be determined based on the target weight average molecular weight of the polymer blocks.

[0102] <Process (2)>

[0103] Next, in step (2), a conjugated diene monomer is added to the solution containing the aromatic vinyl polymer having active terminals obtained in step (1) to polymerize the conjugated diene monomer, thereby obtaining a solution containing an aromatic vinyl-conjugated diene block copolymer having active terminals.

[0104] According to step (2), a conjugated diene monomer is added to the solution containing the aromatic vinyl polymer having an active terminal obtained in the above step (1), thereby forming a conjugated diene polymer chain starting from the active terminal, thereby obtaining a solution containing an aromatic vinyl-conjugated diene block copolymer having an active terminal.

[0105] The conjugated diene polymer chain formed in step (2) (the conjugated diene block constituting the aromatic vinyl-conjugated diene block copolymer having an active terminal obtained in step (2)) constitutes the hydrogenated polymer block HD of the conjugated diene polymer of the hydrogenated block copolymer A. a and the hydrogenated polymer block HD of the conjugated diene polymer of the hydrogenated block copolymer B b Therefore, the polymerization conditions including the amount of the conjugated diene polymer in step (2) may be determined based on the target weight average molecular weight of the polymer blocks, etc. (for example, the polymerization conditions may be determined within the range described in step (1) above).

[0106] <Step (3)>

[0107] Next, in step (3), an aromatic vinyl monomer is added to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active terminal obtained in the above step (2), and the aromatic vinyl monomer is polymerized to obtain a solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active terminal.

[0108] According to step (3), an aromatic vinyl monomer is added to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active terminal obtained in the above step (2), thereby forming an aromatic vinyl polymer chain starting from the active terminal, thereby obtaining a solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active terminal.

[0109] The aromatic vinyl polymer chain formed in step (3) (the aromatic vinyl block constituting the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active terminal obtained in step (3)) constitutes the aromatic vinyl polymer block Ar1 of the hydrogenated block copolymer B. b 、Ar2 b One of (i.e., Ar1 b or Ar2 b In step (1), a block different from the block formed in step (1) is formed. For example, Ar1 b In the case of Ar2 b Therefore, the polymerization conditions including the amount of the aromatic vinyl monomer in step (3) can be determined based on the target weight average molecular weight of the polymer block (for example, the polymerization conditions can be determined within the range described in step (1) above).

[0110] <Step (4)>

[0111] Next, in step (4), a polymerization terminator is added to the solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active terminals obtained in the above step (3) in an amount less than 1 molar equivalent relative to the active terminals, thereby deactivating a portion of the active terminals of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active terminals, thereby obtaining a solution containing block copolymer B'.

[0112] The block copolymer B′ obtained in the step (4) becomes a block copolymer before hydrogenation for obtaining the hydrogenated block copolymer B.

[0113] The polymerization terminator is not particularly limited as long as it can react with the active terminal to inactivate the active terminal and does not react with other active terminals after reacting with one active terminal. It is preferably a compound containing no halogen atoms, and particularly preferably a polymerization terminator that generates a metal alcoholate, a metal aryl oxide or a metal hydroxide when reacting with the active terminal. Specific examples of the polymerization terminator include: water; monohydric alcohols such as methanol and ethanol; monohydric phenols such as phenol and cresol, etc.

[0114] The amount of the polymerization terminator used may be determined according to the ratio of the hydrogenated block copolymer A to the hydrogenated block copolymer B constituting the hydrogenated block copolymer composition, and is not particularly limited as long as it is an amount less than 1 molar equivalent relative to the active ends of the polymer. The amount of the polymerization terminator used is preferably in the range of 0.18 to 0.91 molar equivalents, more preferably in the range of 0.35 to 0.80 molar equivalents relative to the active ends of the polymer.

[0115] As described above, according to step (4), a polymerization terminator is added to a solution containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active terminals in an amount of less than 1 molar equivalent relative to the active terminals, thereby deactivating the active terminals of a portion of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active terminals, and the copolymer having the deactivated active terminals becomes a block copolymer B' before hydrogenation for constituting the hydrogenated block copolymer B. Then, the remaining portion of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having active terminals that has not reacted with the polymerization terminator remains in the solution in an unreacted state with the active terminals being maintained.

[0116] <Step (5)>

[0117] Next, in step (5), an aromatic vinyl monomer is added to the solution containing the block copolymer B' obtained in step (4) to polymerize the aromatic vinyl monomer, thereby obtaining a solution containing the block copolymer B' and the block copolymer A'.

[0118] According to step (5), when an aromatic vinyl monomer is added to the solution obtained in the above step (4), the aromatic vinyl monomer is further polymerized from the aromatic vinyl polymer chain having an active terminal side of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active terminal that remains without reacting with the polymerization terminator, and the aromatic vinyl polymer chain is extended, thereby obtaining a block copolymer A'. In addition, the block copolymer A' is an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer obtained by extending the aromatic vinyl polymer chain, and becomes a block copolymer before hydrogenation for obtaining the hydrogenated block copolymer A.

[0119] In this case, in step (5), the extended aromatic vinyl polymer chain constitutes the aromatic vinyl polymer block Ar2 having a large weight average molecular weight of the hydrogenated block copolymer A constituting the hydrogenated block copolymer composition. a Therefore, the polymerization conditions including the amount of the aromatic vinyl monomer in step (5) are determined based on the aromatic vinyl polymer block Ar2. a The polymerization conditions may be determined based on the target weight average molecular weight, etc. (for example, the polymerization conditions may be determined within the range described in the above step (1)).

[0120] <Step (6)>

[0121] Next, in step (6), the solution containing block copolymer B' and block copolymer A' obtained in step (5) is subjected to a hydrogenation reaction, thereby obtaining a solution containing hydrogenated block copolymer B and hydrogenated block copolymer A.

[0122] The method for hydrogenating the solution containing the block copolymer B' and the block copolymer A' is not particularly limited, and examples thereof include a method of contacting the solution containing the block copolymer B' and the block copolymer A' with hydrogen in the presence of a hydrogenation catalyst.

[0123] The hydrogenation catalyst is not particularly limited, and examples thereof include: a supported heterogeneous catalyst in which a metal such as Ni, Pt, Pd, or Ru is supported on a carrier such as carbon, silica, alumina, or diatomaceous earth; a Ziegler-type catalyst using an organic salt or acetylacetonate of Ni, Co, Fe, or Cr and a reducing agent such as an organic Al; an organic complex catalyst such as an organic metal compound of Ru or Rh; a homogeneous catalyst using an organic Li, an organic Al, or an organic Mg as a reducing agent in a titanocene compound, etc. Among these, a Ziegler-type catalyst is preferred.

[0124] The hydrogenation reaction can be carried out according to the methods disclosed in, for example, Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Application Laid-Open No. 59-133203, and Japanese Patent Application Laid-Open No. 60-220147.

[0125] The conditions of the hydrogenation reaction can be selected according to the hydrogenation rate of the olefin in the polymer component constituting the hydrogenated block copolymer composition. The hydrogenation reaction temperature is preferably 0 to 200° C., and more preferably 30 to 150° C. In addition, the hydrogen pressure used in the hydrogenation reaction is preferably 0.1 to 15 MPa, more preferably 0.2 to 10 MPa, and further preferably 0.3 to 5 MPa. The hydrogenation reaction time is preferably 3 minutes to 10 hours, and more preferably 10 minutes to 5 hours. In addition, the hydrogenation reaction can be any of a batch process, a continuous process, or a combination thereof.

[0126] <Step (7)>

[0127] Next, in step (7), the target hydrogenated block copolymer composition is recovered from the solution containing the hydrogenated block copolymer B and the hydrogenated block copolymer A obtained in step (6).

[0128] The recovery method can be carried out according to conventional methods and is not particularly limited. For example, after the reaction is completed, a polymerization terminator is added as needed to inactivate the active end of the polymer having an active end, and an additive such as an antioxidant is further added as needed, and then the solution is subjected to a known solvent method such as a direct drying method and a stripping method, thereby recovering the target hydrogenated block copolymer composition. In addition, at this time, as the polymerization terminator, the above-mentioned polymerization terminator can be used.

[0129] When the hydrogenated block copolymer composition is recovered as a slurry by steam stripping or the like, it is preferred to recover the hydrogenated block copolymer composition in the form of pellets by dehydrating it using any dehydrator such as an extruder type press, and further dry the obtained pellets using any dryer such as a belt dryer, an expansion extrusion dryer, etc. In addition, the hydrogenated block copolymer composition thus obtained can also be used after being processed into a pellet shape or the like according to a conventional method.

[0130] The solid (granular, pelletized, etc.) hydrogenated block copolymer composition thus obtained is preferably used after reducing the water content contained in the solid hydrogenated block copolymer composition using a dryer such as a hopper dryer, a hot air circulation tray dryer, a tray vacuum dryer, or a stirring vacuum dryer. The drying conditions at this time are not particularly limited as long as the target water content can be obtained, and can be set according to the water content to be reduced, the type of dryer, etc., and are usually set within the range of a drying temperature of 40 to 90° C. and a drying time of 1 to 24 hours.

[0131] According to the method for producing a hydrogenated block copolymer composition, the hydrogenated block copolymer A and the hydrogenated block copolymer B can be continuously obtained in the same reaction vessel. Therefore, the target hydrogenated block copolymer composition can be obtained with excellent productivity compared with the case where each hydrogenated block copolymer is produced separately and mixed.

[0132] When producing the hydrogenated block copolymer composition of the present invention, in addition to the above-mentioned preferred production method (the production method including steps (1) to (7)), it is also preferable to use a production method for a hydrogenated block copolymer composition including the following steps (1a) to (6a).

[0133] (1a): A step of polymerizing an aromatic vinyl monomer in a solvent using a polymerization initiator to obtain a solution containing an aromatic vinyl polymer having an active terminal;

[0134] (2a): a step of adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having an active terminal obtained in the above step (1a) to polymerize the conjugated diene monomer to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having an active terminal;

[0135] (3a): A step of adding a bifunctional coupling agent in an amount less than 1 molar equivalent relative to the total amount of functional groups at the active ends to the solution containing the aromatic vinyl-conjugated diene block copolymer having active ends obtained in the above step (2a), thereby coupling a portion of the aromatic vinyl-conjugated diene block copolymer having active ends to obtain a solution containing block copolymer B';

[0136] (4a): A step of adding an aromatic vinyl monomer to the solution containing the block copolymer B' obtained in the above step (3a) to polymerize the aromatic vinyl monomer to obtain a solution containing the block copolymer B' and the block copolymer A';

[0137] (5a): A step of subjecting the solution containing block copolymer B' and block copolymer A' obtained in the above step (4a) to a hydrogenation reaction to obtain a solution containing hydrogenated block copolymer B and hydrogenated block copolymer A;

[0138] (6a): A step of recovering a hydrogenated block copolymer composition from the solution containing the hydrogenated block copolymer B and the hydrogenated block copolymer A obtained in the step (5a).

[0139] <Step (1a), Step (2a)>

[0140] Step (1a) and step (2a) are the same as the above-mentioned step (1) and step (2), and the same conditions can be employed.

[0141] <Step (3a)>

[0142] In step (3a), a bifunctional coupling agent is added to the solution containing the aromatic vinyl-conjugated diene block copolymer having active terminals obtained in the above step (2a) in an amount less than 1 molar equivalent relative to the total amount of functional groups at the active terminals, so that a part of the aromatic vinyl-conjugated diene block copolymer having active terminals is coupled to obtain a solution containing block copolymer B'.

[0143] The block copolymer B′ obtained in the step (3a) becomes a block copolymer before hydrogenation for obtaining the hydrogenated block copolymer B.

[0144] The bifunctional coupling agent is not particularly limited as long as it has two functional groups that react with the active end, and examples thereof include bifunctional halogenated silanes such as dichlorosilane, monomethyldichlorosilane, and dimethyldichlorosilane; bifunctional halogenated alkanes such as dichloroethane, dibromoethane, dichloromethane, and dibromomethane; and bifunctional tin halides such as tin dichloride, monomethyltin dichloride, dimethyltin dichloride, monoethyltin dichloride, diethyltin dichloride, monobutyltin dichloride, and dibutyltin dichloride.

[0145] The amount of the bifunctional coupling agent used may be determined according to the ratio of the hydrogenated block copolymer A to the hydrogenated block copolymer B constituting the hydrogenated block copolymer composition.

[0146] As described above, according to step (3a), a bifunctional coupling agent is added to a solution containing an aromatic vinyl-conjugated diene block copolymer having an active terminal in an amount of less than 1 molar equivalent relative to the total amount of functional groups at the active terminal, so that a part of the aromatic vinyl-conjugated diene block copolymer having an active terminal is coupled to form a block copolymer B' before hydrogenation for constituting a hydrogenated block copolymer B. The remaining part of the aromatic vinyl-conjugated diene block copolymer having an active terminal that has not reacted with the bifunctional coupling agent remains in the solution in an unreacted state with the active terminal being maintained.

[0147] <Step (4a)>

[0148] Next, in step (4a), an aromatic vinyl monomer is added to the solution containing the block copolymer B' obtained in step (3a) to polymerize the aromatic vinyl monomer, thereby obtaining a solution containing the block copolymer B' and the block copolymer A'.

[0149] According to step (4a), when an aromatic vinyl monomer is added to the solution obtained in the above step (3a), the aromatic vinyl monomer is polymerized from the active end of the aromatic vinyl-conjugated diene block copolymer having an active end that remains without reacting with the bifunctional coupling agent to form an aromatic vinyl polymer chain, thereby obtaining a block copolymer A'. In addition, the block copolymer A' becomes a block copolymer before hydrogenation for obtaining the hydrogenated block copolymer A.

[0150] In this case, the aromatic vinyl polymer chain formed in step (4a) constitutes the aromatic vinyl polymer block Ar2 having a large weight average molecular weight of the hydrogenated block copolymer A constituting the hydrogenated block copolymer composition. a Therefore, the polymerization conditions including the amount of the aromatic vinyl monomer in step (4a) are determined based on the aromatic vinyl polymer block Ar2. a The polymerization conditions may be determined based on the target weight average molecular weight, etc. (for example, the polymerization conditions may be determined within the range described in the above step (1)).

[0151] <Step (5a), Step (6a)>

[0152] Then, the hydrogenated block copolymer composition used in the present invention can be obtained by using the solution containing the block copolymer B' and the block copolymer A' obtained in step (4a) through the operations in the above steps (5a) and (6a). In addition, the above steps (5a) and (6a) are the same as the above steps (6) and (7), and the same conditions can be used.

[0153] [Polyolefin-based thermoplastic resin C]

[0154] The crosslinkable polymer composition of the present invention contains a polyolefin-based thermoplastic resin C in addition to the above-mentioned hydrogenated block copolymer composition.

[0155] As the polyolefin-based thermoplastic resin C used in the present invention, as long as it is a thermoplastic resin with olefin as the main repeating unit, it is not particularly limited, and can be any one of the copolymers of the homopolymer of alpha-olefin, the copolymer of two or more alpha-olefins and the copolymer of the monomer other than alpha-olefin, in addition, it can also be the resin after these (to) polymers are modified. As the polyolefin-based thermoplastic resin C, the content of the preferred aromatic vinyl polymer unit is the polyolefin-based thermoplastic resin below 10 mass %, and the content of the more preferred aromatic vinyl polymer unit is the polyolefin-based thermoplastic resin below 1 mass % (substantially not containing). In addition, as the polyolefin-based thermoplastic resin C, the content of the preferred alpha-olefin unit is the polyolefin-based thermoplastic resin above 50 weight %, and the content of the more preferred alpha-olefin unit is the polyolefin-based thermoplastic resin above 70 weight %, and the further preferred alpha-olefin unit content is the polyolefin-based thermoplastic resin above 80 weight %.

[0156] Examples of the polyolefin-based thermoplastic resin C used in the present invention include homopolymers or copolymers of α-olefins such as ethylene and propylene, for example, linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyethylene such as metallocene polyethylene, polypropylene, metallocene polypropylene, polymethylpentene, polybutene and other α-olefin homopolymers; copolymers of ethylene and other α-olefins, for example, ethylene-propylene random copolymers, ethylene-propylene block copolymers, ethylene-butene-1 copolymers, ethylene-propylene-butene-1 copolymers and ethylene-cyclic olefin copolymers; copolymers of α-olefins mainly composed of α-olefins and vinyl esters and saponified products thereof, for example, ethylene-vinyl acetate copolymers (EVA), ethylene-vinyl alcohol copolymer; copolymers of α-olefins with α-olefin as the main component and α,β-unsaturated carboxylic acid esters or α,β-unsaturated carboxylic acids, such as ethylene-α,β-unsaturated carboxylic acid ester copolymers (ethylene-ethyl acrylate copolymers, ethylene-methyl methacrylate copolymers, etc.), ethylene-α,β-unsaturated carboxylic acid copolymers (ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, etc.); acid-modified olefin resins obtained by modifying α-olefin (co)polymers such as polyethylene and polypropylene with unsaturated carboxylic acids and / or their anhydrides such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, etc.; ionomer resins obtained by reacting Na ions, Zn ions, etc. with copolymers of ethylene and methacrylic acid, etc.; mixtures thereof. In addition, the polyolefin-based thermoplastic resin C may be used alone or in combination of two or more.

[0157] Among these, preferred ethylene resins (polyethylene or copolymers containing ethylene units as the main component) are preferred, and polyethylene is more preferred; copolymers of ethylene and vinyl esters based on ethylene units and saponified products thereof, further preferred linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), ethylene-vinyl acetate copolymers (EVA), ethylene-vinyl alcohol copolymers, particularly preferred low-density polyethylene (LDPE), ethylene-vinyl acetate copolymers (EVA). As ethylene resins, preferably ethylene resins having an ethylene unit content of more than 50% by weight, more preferably ethylene resins having an ethylene unit content of more than 70% by weight, and further preferably ethylene resins having an ethylene unit content of more than 80% by weight. By using the above-mentioned ethylene resins as polyolefin-based thermoplastic resins C, the effect brought about by crosslinking can be further improved, and a crosslinked product having excellent mechanical properties and dimensional stability in addition to excellent high resilience and compression set resistance can be formed with high formability and high productivity.

[0158] The density of polyolefin thermoplastic resin C is usually between 0.80 and 0.97 g / cm 3 The range is preferably 0.85 to 0.96 g / cm 3 The range of is preferably 0.88 to 0.95 g / cm 3 range to select.

[0159] In the cross-linkable polymer composition of the present invention, the ratio of the content of the polyolefin-based thermoplastic resin C to the total content of the hydrogenated block copolymer A and the hydrogenated block copolymer B (C / (A+B)) is 5 / 95 to 80 / 20 by weight. Whether the above ratio (C / (A+B)) is too small or too large, it is difficult to take into account both the high resilience and compression set resistance of the obtained cross-linked product. In addition, if the above ratio (C / (A+B)) is too small, it is difficult to take into account both the high resilience and compression set resistance of the obtained cross-linked product, and further, poor molding is likely to occur in the case of molding simultaneously with cross-linking or in the case of molding after cross-linking. The above ratio (C / (A+B)) is preferably 10 / 90 to 70 / 30, more preferably 12 / 88 to 60 / 40, and further preferably 15 / 85 to 50 / 50. By setting the ratio (C / (A+B)) within the above range, the effect of crosslinking can be further enhanced, and a crosslinked product having high rebound resilience and compression set resistance as well as excellent mechanical properties and dimensional stability can be formed with high moldability and high productivity.

[0160] [Crosslinking agent]

[0161] The crosslinkable polymer composition of the present invention contains a crosslinking agent in addition to the hydrogenated block copolymer composition and the polyolefin-based thermoplastic resin C described above.

[0162] Examples of the crosslinking agent include chemical crosslinking agents such as peroxide crosslinking agents and sulfur crosslinking agents, and photocrosslinking agents. The crosslinking agent may be used alone or in combination of two or more.

[0163] Examples of the peroxide-based crosslinking agent include organic peroxide-based crosslinking agents such as tert-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl cumene peroxide, 2,5-dimethyl-tert-butylperoxyhexane, 2,5-dimethyl-tert-butylperoxyhexyne, 1,3-bis(tert-butylperoxyisopropyl)benzene, p-chlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, tert-butyl benzoate, and 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

[0164] When a peroxide-based crosslinking agent is used, as a crosslinking aid, a polyfunctional unsaturated compound such as trimethylolpropane trimethacrylate, divinylbenzene, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl itaconate, triallyl trimellitate, etc. can be used.

[0165] Examples of the sulfur-based crosslinking agent include sulfur such as powdered sulfur, sublimed sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, and insoluble sulfur; sulfur compounds such as sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, N,N'-dithio-bis(hexahydro-2H-azepinone-2), phosphorus-containing polysulfide, and polymer polysulfide; and tetramethylthiuram disulfide, selenium dimethyldithiocarbamate, and 2-(4'-morpholinodithio)benzothiazole, etc. When a sulfur-based crosslinking agent is used, as a vulcanization accelerator, and further, a sulfur crosslinking agent, in addition to these sulfur-based crosslinking agents, stearic acid; guanidine-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, sulfenamide-based, thiourea-based, and xanthate-based vulcanization accelerators may be used.

[0166] Photocrosslinking agent can be any single compound or combination of compounds that can generate free radicals that initiate polymerization of one or more monomers but do not cause excessive termination reactions by sensing light such as ultraviolet rays (UV). As known photocrosslinking agent, in particular, free radical photoinitiators such as quinone, benzophenone, benzoin ether, allyl ketone, peroxide, bisimidazole, benzyl dimethyl ketal, hydroxyalkylphenyl acetophenone (acetophone), dialkoxyacetophenone (actophenone), trimethylbenzoylphosphine oxide derivatives such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, aminoketone, benzoyl cyclohexanol, methylthiophenylmorpholinone, phenylaminomorpholinone, α-haloacetophenone, oxygen sulfonyl ketone, sulfonyl ketone, oxygen sulfonyl ketone, benzoyl oxime ester, 2-isopropylthioxanthone, camphorquinone, ketocoumarin, and Michler's ketone can be used. Alternatively, the photocrosslinking agent may be a mixture of compounds providing free radicals in the case where one of the photocrosslinking agents is initiated by a photosensitizer activated by radiation. The photocrosslinking agent may be a photocrosslinking agent that is preferably responsive to visible light or ultraviolet light (chemical rays). In addition, the photocrosslinking agent may also be used in combination with a free radical photoinitiator and the above-mentioned multifunctional unsaturated compound.

[0167] The crosslinking agent used in the present invention is not limited to the above-mentioned crosslinking agents, and may be a crosslinking agent that can crosslink the crosslinkable polymer composition of the present invention in response to active energy rays such as electron beams and radiation.

[0168] The crosslinking agent used in the present invention is not particularly limited, but an organic peroxide-based crosslinking agent is preferred, and dicumyl peroxide is more preferred.

[0169] The content of the crosslinking agent is preferably in the range of 0.01 to 20 parts by mass, more preferably in the range of 0.1 to 10 parts by mass, and further preferably in the range of 0.5 to 5 parts by mass, relative to 100 parts by mass of the total content (A+B+C) of the hydrogenated block copolymer A, the hydrogenated block copolymer B, and the polyolefin-based thermoplastic resin C in the crosslinkable polymer composition of the present invention. By making the content of the crosslinking agent within the above range, the effect of crosslinking can be further enhanced, and a crosslinked product having excellent mechanical properties and dimensional stability in addition to high resilience and compression set resistance can be formed with high moldability and high productivity.

[0170] [Other ingredients]

[0171] The crosslinkable polymer composition of the present invention may further contain an antioxidant, zinc oxide, a foaming agent, a foaming aid, a filler, a tackifying resin, a softener, an antibacterial agent, a light stabilizer, an ultraviolet absorber, a dye, a lubricant, and the like as necessary.

[0172] The crosslinkable polymer composition of the present invention may contain an antioxidant as required. The type of antioxidant is not particularly limited, and examples thereof include hindered phenol compounds such as pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-p-cresol, and di-tert-butyl-4-methylphenol; thiodicarboxylates such as dilaurylthiopropionate; and phosphites such as tris(nonylphenyl)phosphite. The antioxidant may be used alone or in combination of two or more.

[0173] The content of the antioxidant is not particularly limited, and is generally 10 parts by weight or less, preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the total content (A+B+C) of the hydrogenated block copolymer A, the hydrogenated block copolymer B, and the polyolefin-based thermoplastic resin C in the crosslinkable polymer composition of the present invention. In addition, the timing of adding the antioxidant to the crosslinkable polymer composition is not particularly limited, and for example, it can be added in advance to the hydrogenated block copolymer composition used to constitute the crosslinkable polymer composition, or it can be added when the hydrogenated block copolymer composition and the polyolefin-based thermoplastic resin C are mixed.

[0174] The crosslinkable polymer composition of the present invention may contain zinc oxide as needed. The content of zinc oxide is not particularly limited, but is generally 10 parts by weight or less, preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the total content (A+B+C) of the hydrogenated block copolymer A, the hydrogenated block copolymer B, and the polyolefin-based thermoplastic resin C in the crosslinkable polymer composition of the present invention.

[0175] When the crosslinkable polymer composition of the present invention is used to produce a crosslinked foam, the crosslinkable polymer composition of the present invention may contain a foaming agent as required. The type of the foaming agent is not particularly limited, and examples thereof include chemical foaming agents such as thermal decomposition foaming agents and reactive foaming agents; physical foaming agents, etc. In addition, the foaming agent may be used alone or in combination of two or more.

[0176] Examples of the thermally decomposable foaming agent include organic thermally decomposable foaming agents such as azo compounds, nitroso compounds, hydrazine derivatives, semicarbazide compounds, tetrazole compounds, and organic acids; and inorganic thermally decomposable foaming agents such as bicarbonates, carbonates, organic acid salts, and nitrites.

[0177] More specifically, as azo compounds, azodicarbonamide (ADCA), azobisisobutyronitrile (AIBN), barium azodicarboxylate, diazoaminobenzene, etc. can be mentioned. As nitroso compounds, for example, dinitrosopentamethylenetetramine (DPT) can be mentioned. As hydrazine derivatives, for example, p,p'-oxybis(benzenesulfonylhydrazide) (OBSH), p-toluenesulfonylhydrazide (TSH), hydrazine dicarbonamide (HDCA), etc. can be mentioned. As semicarbazide compounds, for example, p-toluenesulfonyl semicarbazide can be mentioned. In addition, as tetrazole compounds, for example, 5-phenyltetrazole, 1,4-bitetrazole, etc. can be mentioned. As organic acids, for example, polycarboxylic acids such as citric acid, oxalic acid, fumaric acid, phthalic acid, malic acid, and tartaric acid can be mentioned.

[0178] Examples of the reactive foaming agent include a combination of an isocyanate compound and water, a combination of sodium hydrogen carbonate and an acid, a combination of hydrogen peroxide and yeast, and a combination of zinc powder and an acid.

[0179] Examples of the physical foaming agent include gases such as freon gas and carbon dioxide gas; volatile liquids such as water and volatile hydrocarbon compounds; and heat-expandable microcapsules containing these gases, volatile liquids, and the like.

[0180] Among these, from the viewpoint of achieving a high expansion ratio, a chemical foaming agent is preferred, a thermal decomposition type foaming agent is more preferred, an azo compound is further preferred, and azodicarbonamide (ADCA) is particularly preferred.

[0181] The content of the foaming agent is not particularly limited as long as it is determined according to the target expansion ratio, etc., but is preferably in the range of 0.1 to 20 parts by mass, more preferably in the range of 0.2 to 10 parts by mass, and further preferably in the range of 0.5 to 5 parts by mass, based on 100 parts by mass of the total content (A+B+C) of the hydrogenated block copolymer A, the hydrogenated block copolymer B, and the polyolefin-based thermoplastic resin C in the crosslinkable polymer composition of the present invention.

[0182] In addition, the cross-linkable polymer composition of the present invention can effectively suppress the leakage of bubbles from the cross-linkable polymer composition during cross-linking and foaming, and can be foamed at a high expansion ratio. Therefore, by adding the above-mentioned preferred foaming agent in the above-mentioned preferred amount, the cross-linkable polymer composition can be foamed at a high expansion ratio while effectively suppressing the leakage of bubbles from the cross-linkable polymer composition.

[0183] When a foaming agent is used, it is preferred to further use a foaming aid such as urea. The content of the foaming aid is not particularly limited, but is preferably 10 to 300 parts by weight, more preferably 20 to 100 parts by weight, relative to 100 parts by weight of the cross-linking agent in the cross-linkable polymer composition of the present invention. In addition, the content of the foaming aid is not particularly limited, but is preferably 10 to 300 parts by weight, more preferably 20 to 100 parts by weight, relative to 100 parts by weight of the foaming agent in the cross-linkable polymer composition of the present invention.

[0184] The crosslinkable polymer composition of the present invention may contain a filler as required. The type of filler is not particularly limited, and examples thereof include clay, titanium oxide, silicon oxide, talc, calcium carbonate, carbon black, etc. The filler may be used alone or in combination of two or more.

[0185] The content of the filler is not particularly limited, but is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, and further preferably 5 parts by weight or less, relative to 100 parts by weight of the total content (A+B+C) of the hydrogenated block copolymer A, the hydrogenated block copolymer B, and the polyolefin-based thermoplastic resin C in the crosslinkable polymer composition of the present invention.

[0186] The crosslinkable polymer composition of the present invention may contain polymer components other than the hydrogenated block copolymer A, the hydrogenated block copolymer B, and the polyolefin-based thermoplastic resin C as long as the effects of the present invention are not impaired.

[0187] Examples of polymer components other than the hydrogenated block copolymer A, the hydrogenated block copolymer B and the polyolefin-based thermoplastic resin C that may be contained in the crosslinkable polymer composition of the present invention include: aromatic vinyl-conjugated diene-aromatic vinyl block copolymers other than the hydrogenated block copolymer A and the hydrogenated block copolymer B, aromatic vinyl-conjugated diene block copolymers, aromatic vinyl homopolymers, conjugated diene homopolymers, aromatic vinyl-conjugated diene random copolymers, and branched polymers thereof; thermoplastic elastomers such as polyurethane-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and polyester-based thermoplastic elastomers; and thermoplastic resins such as polyvinyl chloride, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, and polyphenylene ether.

[0188] In the crosslinkable polymer composition of the present invention, the content of the polymer components other than the hydrogenated block copolymer A, the hydrogenated block copolymer B and the polyolefin-based thermoplastic resin C is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, further preferably 5 parts by weight, particularly preferably 1 part by weight or less, and most preferably substantially 0 parts by weight, based on 100 parts by weight of the total content (A+B+C) of the hydrogenated block copolymer A, the hydrogenated block copolymer B and the polyolefin-based thermoplastic resin C in the crosslinkable polymer composition of the present invention.

[0189] [Crosslinkable polymer composition]

[0190] The shape of the crosslinkable polymer composition of the present invention is not particularly limited, and can be appropriately molded into a desired shape, such as a pellet, a sheet, a strand, or a chip.

[0191] The crosslinkable polymer composition of the present invention can be produced by, for example, a method of mixing a block copolymer composition, a polyolefin-based thermoplastic resin C, a crosslinking agent, and various additives used as necessary.

[0192] As a method for mixing these components, there is no particular limitation, and examples include: a method of heating and melting the components with a mixing device such as a roller, a Banbury mixer, a kneader, a laboratory mixing extruder (Labo Plastomill), a single screw extruder, a twin screw extruder, etc.; a method of removing the solvent by heating, etc. after the components are dissolved in a solvent and uniformly mixed. Among these, from the viewpoint of more efficient mixing, a method of heating and melting mixing is preferably performed. In addition, the temperature during heating and melting mixing is preferably in a temperature range that can suppress excessive decomposition of the components and perform an unexpected crosslinking reaction, for example, preferably in a temperature range of 90 to 150° C., more preferably in a temperature range of 100 to 130° C.

[0193] [Cross-linked products]

[0194] The crosslinked product of the present invention can be obtained by crosslinking the crosslinkable polymer composition of the present invention. The crosslinked product of the present invention has excellent high rebound resilience and compression set resistance in a well-balanced manner.

[0195] The method for crosslinking the crosslinkable polymer composition is not particularly limited, and a known method can be used according to the type of crosslinking agent, the shape of the target crosslinked product, etc. For example, in the case of a chemical crosslinking system, the crosslinkable polymer composition can be crosslinked by heating. The heating temperature at this time is preferably, for example, 130 to 250° C., more preferably 140 to 200° C., and the heating time is preferably, for example, 1 minute to 60 minutes.

[0196] The crosslinked product of the present invention is obtained by crosslinking the crosslinkable polymer composition of the present invention, and therefore contains the hydrogenated block copolymer A, the hydrogenated block copolymer B, and the polyolefin-based thermoplastic resin C. The content ratio of these components in the crosslinked product is the same as the content ratio of these components in the crosslinkable polymer composition, and the preferred range is also the same.

[0197] The crosslinked product of the present invention is usually a crosslinked product (crosslinked shaped product) obtained by crosslinking and shaping the crosslinkable polymer composition of the present invention. The timing of crosslinking and shaping may be simultaneous or different.

[0198] [Cross-linked foam]

[0199] The cross-linked product of the present invention may be a cross-linked foamed product obtained by cross-linking and foaming the cross-linkable polymer composition of the present invention. The present invention also relates to such a cross-linked foamed product.

[0200] The cross-linked foam of the present invention has a good balance between high resilience and compression set resistance. In addition, the cross-linked polymer composition of the present invention can effectively suppress the leakage of bubbles from the cross-linked polymer composition during cross-linking and foaming, so it can be foamed at a high foaming ratio, not only can the apparent density of the cross-linked foam of the present invention be reduced, but also a cross-linked foam with excellent uniformity can be formed.

[0201] The method for producing the cross-linked foam of the present invention is not particularly limited, and the following method can be cited, for example: a cross-linked polymer composition containing a chemical foaming agent is used as the cross-linked polymer composition of the present invention, and the cross-linked polymer composition is heated and compressed in a state of being inserted into a mold, thereby performing cross-linking and decomposition of the foaming agent, and then the mold is opened to foam the composition. According to such a production method, the composition can be foamed at a high foaming ratio.

[0202] The conditions for heating and compressing are not particularly limited. The heating and compressing temperature is usually 130 to 250° C., preferably 140 to 200° C., the heating and compressing pressure is usually 1 to 30 MPa, preferably 3 to 20 MPa, and the heating and compressing time is usually 1 to 90 minutes, preferably 5 to 30 minutes.

[0203] As a method for producing the crosslinked foam of the present invention, the following method can be adopted: after the crosslinkable polymer composition of the present invention is foamed by a known method, it is crosslinked by a known method. In this method, for example, the following method can be cited: the crosslinkable polymer composition of the present invention is mixed with a physical foaming agent, and then the physical foaming agent dissolved or dispersed in the crosslinkable polymer composition of the present invention is converted into a gas phase, thereby foaming it, and then crosslinking it.

[0204] The physical foaming agent is a liquefied gas or a supercritical fluid, which is converted into a gas phase by decompression and heating. Examples of the physical foaming agent include aliphatic hydrocarbons such as butane, alicyclic hydrocarbons such as cyclobutane, and inorganic gases such as carbon dioxide, nitrogen, and air. Among them, a supercritical fluid is preferred, a supercritical fluid of carbon dioxide and nitrogen is more preferred, and a supercritical fluid of nitrogen is further preferred.

[0205] As a foaming method, for example, an injection molding foaming method can be mentioned. Specifically, a thermoplastic component in a cross-linkable polymer composition is plasticized in a barrel, and a physical foaming agent is injected into the barrel, thereby dissolving or dispersing the physical foaming agent in the plasticized component, and then the obtained mixture is injected into a mold, and after or at the same time as the injection, the physical foaming agent in the mixture is converted into a gas phase, thereby enabling the mixture to be foamed.

[0206] As an injection molding foaming method for converting a physical foaming agent in a mixture into a gas phase after or at the same time as injection, there can be mentioned a short shot method, a full shot method, a core back method, etc. Among them, the core back method is preferred from the viewpoint of being able to uniformly generate bubbles in the foam. In addition, the core back method is a method in which a mold capable of expanding the cavity volume is used to expand the cavity volume of the mold after or at the same time as injection molding, thereby converting the physical foaming agent into a gas phase.

[0207] In addition, as a foaming method, a method using various other melt molding machines such as an extrusion molding machine instead of an injection molding machine can be adopted. In addition, from the viewpoint of further improving the expansion ratio (i.e., further reducing the apparent density of the cross-linked foam), after the mixture is foamed, the foamed mixture can be heated again to further foam.

[0208] As the cross-linking method, the various cross-linking methods described above can also be adopted.

[0209] The apparent density of the crosslinked foam of the present invention is not particularly limited, but is preferably 0.06 to 0.60 g / cm 3 , more preferably 0.10 to 0.55 g / cm 3 , more preferably 0.12 to 0.50 g / cm 3 Since the cross-linked foam of the present invention is obtained by using the cross-linkable polymer composition of the present invention, even when the foaming ratio is high (in other words, the apparent density of the obtained cross-linked foam is low, for example, 0.22 g / cm 3 In the following cases), high rebound resilience and compression set resistance can be well balanced and excellent, and uniformity can also be excellent.

[0210] [Other cross-linked molded articles]

[0211] The cross-linked product of the present invention is not limited to the above-mentioned cross-linked foamed product, and may be, for example, a cross-linked molded product obtained by cross-linking the cross-linkable polymer composition of the present invention and molding it into any shape such as fiber, film, tube, etc. The method for producing the cross-linked molded product is not particularly limited, and may be, for example, a method of cross-linking the cross-linkable polymer composition of the present invention after molding it, or a method of molding a preform obtained by pre-molding the cross-linkable polymer composition of the present invention after cross-linking it.

[0212] As described above, by using the cross-linkable polymer composition of the present invention, it is possible to form a cross-linked body while being subjected to a large deformation as required or after being cross-linked (for example, forming a cross-linked body at a high stretch ratio). Therefore, as a method for producing a cross-linked molded body, the following method can be preferably used: after cross-linking a preform obtained by preforming the cross-linkable polymer composition of the present invention, the preform is subjected to a large deformation and formed (for example, forming a cross-linked body at a high stretch ratio). Moreover, by such a production method, a cross-linked molded body having excellent mechanical properties and dimensional stability in addition to high resilience and excellent resistance to compression set can be produced. Such a production method is suitable for producing cross-linked molded bodies such as fibers, films, and tubes. In addition, as a molding method (for example, a stretching method) in this case, a known molding method can be appropriately used according to the shape of the target cross-linked molded body, and as a cross-linking method, the above-mentioned various cross-linking methods can be used.

[0213] [use]

[0214] The crosslinked product obtained by crosslinking the crosslinkable polymer composition of the present invention has excellent well-balanced high rebound resilience and compression set resistance, and can be suitably used in various applications such as clothing, daily necessities, medical equipment, electronic equipment, electrical appliances, packaging materials, transporters, building materials, and components thereof.

[0215] In addition, the cross-linked foam of the present invention has a good balance of high resilience and compression set resistance, excellent uniformity, and can also have a low apparent density as required. Therefore, it can be suitable for the above-mentioned various uses, especially for uses requiring excellent resilience, compression set resistance and uniformity, and also requiring lightness as required, such as various cushioning material uses such as midsoles of shoes, cushioning materials for batteries, and sealing strips.

[0216] Example

[0217] Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not limited to these examples. In addition, "parts" and "%" are weight references unless otherwise specified. The test methods carried out in the present examples and comparative examples are as follows.

[0218] [Weight Average Molecular Weight and Molecular Weight Distribution of Hydrogenated Block Copolymer Composition (Overall)]

[0219] The molecular weight was calculated based on the polystyrene conversion chart obtained by high performance liquid chromatography with tetrahydrofuran as the carrier at a flow rate of 0.35 ml / min. The apparatus was HLC8320 manufactured by Tosoh Corporation, the chromatographic column was a device formed by connecting three Shodex (registered trademark) KF-404HQ manufactured by Showa Denko K.K. (chromatographic column temperature 40°C), the detector used a differential refractometer and an ultraviolet detector, and the molecular weight was calibrated using 12 points of standard polystyrene (5 to 3 million) manufactured by Polymer Laboratories Ltd.

[0220] [Weight ratio of each block copolymer]

[0221] It was determined from the area ratio of the peaks corresponding to the respective block copolymers in the chart obtained by the above-mentioned high performance liquid chromatography.

[0222] [Weight Average Molecular Weight of Styrene Polymer Block of Each Block Copolymer]

[0223] The (hydrogenated) block copolymer was reacted with ozone according to the method described in Rubber Chem. Technol., 45, 1295 (1972), and reduced with lithium aluminum hydride, thereby decomposing the isoprene polymer block of the (hydrogenated) block copolymer.

[0224] Specifically, the following steps are performed. That is, 300 mg of the sample is dissolved in a reaction vessel containing 100 ml of dichloromethane treated with molecular sieves. The reaction vessel is placed in a cooling tank, set to -25 ° C, and then oxygen is introduced into the reaction vessel at a flow rate of 170 ml / min, while ozone generated by an ozone generator is introduced. After 30 minutes from the start of the reaction, the gas flowing out of the reaction vessel is introduced into an aqueous solution of potassium iodide, thereby confirming that the reaction is complete. Then, 50 ml of diethyl ether and 470 mg of lithium aluminum hydride are added to another reaction vessel after nitrogen substitution, and the reaction vessel is cooled with ice water while the solution after the reaction with ozone is slowly added to the reaction vessel. Then, the reaction vessel is placed in a water bath, gradually heated, and refluxed at 40 ° C for 30 minutes. After that, dilute hydrochloric acid is added to the reaction vessel in small amounts while stirring the solution, and the addition is continued until the generation of hydrogen can hardly be confirmed. After the reaction, the solid product produced in the solution was filtered out and extracted with 100 ml of diethyl ether for 10 minutes. The extract was combined with the filtrate during filtration, and the solvent was distilled off to obtain a solid sample. The weight average molecular weight of the sample thus obtained was measured according to the above-mentioned weight average molecular weight determination method, and the value was used as the weight average molecular weight of the styrene polymer block.

[0225] [Weight Average Molecular Weight of the (Hydrogenated) Isoprene Polymer Block of Each Block Copolymer]

[0226] The weight average molecular weight of the (hydrogenated) isoprene polymer block was determined based on the calculated value by subtracting the weight average molecular weight of the corresponding styrene polymer block from the weight average molecular weight of each block copolymer determined as described above.

[0227] [Vinyl bond content of (hydrogenated) isoprene polymer block]

[0228] Based on the use of deuterated chloroform as solvent 1 The value was determined by H-NMR measurement.

[0229] [Styrene unit content of each block copolymer]

[0230] It was determined based on the detection intensity ratio of the differential refractometer and the ultraviolet detector in the measurement using the above-mentioned high performance liquid chromatography. In addition, copolymers having different styrene unit contents were prepared in advance, and a calibration curve was prepared using these.

[0231] [Styrene unit content of hydrogenated block copolymer composition (overall)]

[0232] Based on the use of deuterated chloroform as solvent 1 The value was determined by H-NMR measurement.

[0233] [Olefin hydrogenation ratio (mol %) of hydrogenated block copolymer composition (overall)]

[0234] By using deuterated chloroform as solvent 1 By H-NMR spectrum measurement, the olefin amounts of the block copolymer composition before hydrogenation and the hydrogenated block copolymer composition after hydrogenation were determined, and the olefin hydrogenation rate (mol %) was calculated based on the difference in olefin amounts before and after hydrogenation.

[0235] exist 1 In the H-NMR spectrum measurement, deuterated chloroform was used as a solvent, and JMN-AL series AL400 (manufactured by JEOL Ltd.) was used as an NMR measurement apparatus.

[0236] In the present examples and comparative examples, both the block copolymer composition before hydrogenation and the hydrogenated block copolymer composition after hydrogenation contained only isoprene units as units derived from olefin monomers. Therefore, during measurement, the hydrogenation rate of isoprene was determined and used as the olefin hydrogenation rate.

[0237] [Density of hydrogenated block copolymer composition]

[0238] The capacity is 100cm 3 A volumetric flask is filled with about 10 g of the hydrogenated block copolymer composition, and the mass of the hydrogenated block copolymer composition is accurately weighed. Next, the volumetric flask filled with the hydrogenated block copolymer composition is accurately filled to the scale line with isopropanol while being careful not to mix in bubbles. The mass of isopropanol added to the volumetric flask is accurately weighed, and the density (g / cm2) of the hydrogenated block copolymer composition is calculated based on the following formula (I): 3 ).

[0239] .

[0240] [Moldability of cross-linkable polymer composition]

[0241] The moldability was evaluated based on whether or not foam molding could be performed in Examples and Comparative Examples.

[0242] Good: Foam molding is possible.

[0243] Bad: Foam molding cannot be performed.

[0244] [Apparent density of cross-linked foam (cross-linked product)]

[0245] After the mass of the cross-linked foam (cross-linked product) is accurately weighed, the volume of the cross-linked foam (cross-linked product) is measured by a water displacement method, and the apparent density of the cross-linked foam (cross-linked product) is calculated based on these measurement results.

[0246] [50% compressive stress]

[0247] A universal testing machine (manufactured by Instron, double-column table universal testing system 5969 load cell type 50 kN) was used to compress the cross-linked foam (cross-linked product) sample at a temperature of 23° C. and a compression rate of 2.0 mm / min to obtain a compression stress-strain curve. Based on the obtained compression stress-strain curve, the 50% compression stress of the cross-linked foam (cross-linked product) was determined.

[0248] [Compression set]

[0249] The compression set of the cross-linked foam (cross-linked product) was measured under compression conditions of a compression rate of 50%, a temperature of 50° C., and a compression time of 5 hours in accordance with JIS-K6262.

[0250] [Production Example 1]

[0251] (1) Production of block copolymer composition before hydrogenation

[0252] 56.6 kg of cyclohexane, 397 mmol of dibutyl ether and 1.18 kg of styrene were added to the pressure reactor. While stirring the entire contents at 50°C, 213 mmol of n-butyl lithium (1.6 M solution) was added. After the addition was completed, the temperature was raised to 55°C for 1 hour for polymerization reaction (first stage of polymerization). The polymerization conversion rate of styrene at this time was 100%.

[0253] While the temperature was controlled to maintain at 50 to 60° C., 5.00 kg of isoprene was continuously added to the reactor over 1 hour. After the addition of isoprene was completed, polymerization reaction was further performed for 1 hour (second stage of polymerization). The polymerization conversion rate of isoprene at this time was 100%.

[0254] Next, while the temperature was controlled to be maintained at 50 to 60° C., 1.18 kg of styrene was continuously added over a period of 1 hour. After the addition of styrene was completed, a polymerization reaction was further performed for 1 hour, thereby obtaining a solution containing a styrene-isoprene-styrene triblock copolymer having an active terminal (third polymerization stage). The polymerization conversion rate of styrene at this time was 100%.

[0255] Next, 148 mmol of methanol was added as a polymerization terminator and mixed to deactivate some of the active ends of the styrene-isoprene-styrene triblock copolymer having active ends, thereby obtaining a solution containing a styrene-isoprene-styrene triblock copolymer as a block copolymer B' for obtaining a hydrogenated block copolymer B.

[0256] After that, 2.65 kg of styrene was continuously added over 1 hour while the temperature was kept at 50-60°C. After the addition of styrene was completed, a polymerization reaction was further performed for 1 hour to obtain a solution containing a styrene-isoprene-styrene triblock copolymer with an active terminal as a block copolymer A' for obtaining a hydrogenated block copolymer A (the fourth polymerization stage). At this time, the polymerization conversion rate of styrene was 100%.

[0257] Finally, 278 mmol of methanol was added as a polymerization terminator and mixed, thereby completely deactivating the active ends of the styrene-isoprene-styrene triblock copolymer having active ends, completing the polymerization reaction, thereby obtaining a solution containing a block copolymer composition before hydrogenation. The amounts of each reagent used in the reaction are summarized in Table 1.

[0258] (2) Hydrogenation reaction of block copolymer composition before hydrogenation

[0259] The solution of the block copolymer composition obtained above before hydrogenation is subjected to a hydrogenation reaction, thereby obtaining a solution containing a hydrogenated block copolymer composition. The hydrogenation reaction is carried out as follows: Ni(AcAc)2-TIBAL catalyst as a hydrogenation catalyst is added to the solution of the block copolymer composition obtained above before hydrogenation at a ratio of 0.5% relative to the block copolymer composition before hydrogenation, and the hydrogenation reaction is carried out under the conditions of a hydrogen pressure of 3MPa, a reaction temperature of 80°C, and a reaction time of 3 hours. A portion of the solution containing the hydrogenated block copolymer composition thus obtained is taken out and measured according to the above method. The results are shown in Table 2.

[0260] (3) Recovery of hydrogenated block copolymer composition

[0261] 0.3 parts of 2,6-di-tert-butyl-p-cresol as an antioxidant were added to 100 parts of the solution containing the hydrogenated block copolymer composition obtained as above and mixed, and the mixed solution was dripped into warm water heated to 85-95°C in small amounts, and the solvent was volatilized to obtain a precipitate. The obtained precipitate was crushed and dried with hot air at 85°C, thereby recovering the granular hydrogenated block copolymer composition. The granular hydrogenated block copolymer composition was supplied to a single screw extruder having an underwater heat cutting device at the front end of the extruder to form cylindrical particles with an average diameter of 5 mm and an average length of about 5 mm. The particles were put into a hopper dryer heated to 60°C, and dried for 10 hours while passing dry air at 60°C to obtain a hydrogenated block copolymer composition. Then, the density of the obtained hydrogenated block copolymer composition was measured according to the above method. The results are shown in Table 2.

[0262] [Production Examples 2 to 4]

[0263] The results are shown in Table 2. A hydrogenated block copolymer composition was obtained in the same manner as in Production Example 1 except that the amounts of the reagents used in the reaction were changed to the amounts shown in Table 1.

[0264] In addition, in Preparation Examples 3 and 4, after the third stage of polymerization, methanol as a polymerization terminator in an amount described in Table 1 was added and mixed, thereby completely deactivating the active ends of the styrene-isoprene-styrene triblock copolymer having active ends, completing the polymerization reaction, thereby obtaining a solution containing a block copolymer composition before hydrogenation. Then, using the obtained solution containing the block copolymer composition before hydrogenation, the same procedure as in Preparation Example 1 was performed except that the hydrogenated block copolymer composition was obtained.

[0265] [Table 1]

[0266] .

[0267] [Table 2]

[0268] .

[0269] [Examples 1 to 4, Comparative Examples 1 to 4]

[0270] The blending components shown in Table 3 were kneaded at a kneading temperature of 120° C. using a roller as a kneading machine to obtain a crosslinkable polymer composition. The obtained crosslinkable polymer composition was inserted into a mold, and the crosslinkable polymer composition in the mold was compressed for 10 minutes using a compression molding machine at a temperature of 160° C. and a pressure of 15 MPa, and then the mold was opened to crosslink and foam the crosslinkable polymer composition to produce a crosslinked foam (crosslinked product). Then, the moldability of the crosslinkable polymer composition was evaluated according to the above method. The results are shown in Table 3.

[0271] In Comparative Example 1, when the mold was opened, the gas for foaming leaked out of the cross-linkable polymer composition, and the cross-linkable polymer composition could not be foamed.

[0272] In addition, after the cross-linked foam (cross-linked product) produced was left to stand at room temperature for 24 hours, it was cut into a sample of 3 cm in length × 3 cm in width × 1 cm in thickness. The obtained sample was used to measure the apparent density, 50% compressive stress and compression set of the cross-linked foam (cross-linked product). The results are shown in Table 3. In addition, in Comparative Example 1, no foam was obtained, so the apparent density of the residue remaining in the mold was measured.

[0273] In addition, each compounding component shown in Table 3 is as follows.

[0274] EVA: cross-linked ethylene-vinyl acetate copolymer (the content of vinyl acetate units is 15%), density 0.936 g / cm 3 , manufactured by Tosoh Co., Ltd., trade name "Ultracene 630";

[0275] LDPE: low-density polyethylene, density 0.920g / cm 3 , manufactured by Japan Polypropylene Co., Ltd., trade name "NOVATECY F30";

[0276] ADCA: azodicarbonamide, a chemical foaming agent, manufactured by Eiwa Chemicals Co., Ltd., trade name “ADCA AY-7”;

[0277] Foaming aid: A foaming aid with urea as the main component, manufactured by Eiwa Chemicals Co., Ltd., trade name "Cellpaste K5";

[0278] Dicumyl peroxide: a crosslinking agent, manufactured by NOF Corporation, trade name “PERCUMYL D”.

[0279] [Table 3]

[0280] .

[0281] As shown in Table 3, according to a cross-linkable polymer composition having a hydrogenated block copolymer A represented by the general formula (A) and a hydrogenated block copolymer B represented by the general formula (B) at a specific weight ratio (A / B), a hydrogenated block copolymer composition having an olefin hydrogenation rate of 10 to 100% and a polyolefin-based thermoplastic resin C at a specific ratio (C / (A+B)), and further containing a cross-linking agent, it is possible to form a cross-linked foam (cross-linked product) having excellent moldability and a good balance between high resilience and compression set resistance (Examples 1 to 4).

[0282] On the other hand, when the polyolefin-based thermoplastic resin C was not contained, a cross-linked foam (cross-linked product) was not obtained and the moldability was poor (Comparative Example 1).

[0283] Furthermore, when the content of the hydrogenated block copolymer composition is too small, the obtained cross-linked foam (cross-linked product) is inferior in compression set resistance (Comparative Example 2).

[0284] Furthermore, when the hydrogenated block copolymer A represented by the general formula (A) was not contained, the obtained cross-linked foam (cross-linked product) could not achieve both high rebound resilience and compression set resistance (Comparative Examples 3 and 4).

Claims

1. A crosslinkable polymer composition comprising: A hydrogenated block copolymer composition comprising a hydrogenated block copolymer A represented by the following general formula (A) and a hydrogenated block copolymer B represented by the following general formula (B); Polyolefin-based thermoplastic resin C; and Crosslinking agent, The hydrogenation rate of olefins in the polymer components constituting the hydrogenated block copolymer composition is 10 to 100%, The weight ratio (A / B) of the hydrogenated block copolymer A to the hydrogenated block copolymer B in the hydrogenated block copolymer composition is 10 / 90 to 80 / 20, The ratio of the content of the polyolefin-based thermoplastic resin C to the total content of the hydrogenated block copolymer A and the hydrogenated block copolymer B (C / (A+B)) is 5 / 95 to 80 / 20 by weight. In the general formula (A) and the general formula (B), Ar1 a 、Ar2 a 、Ar1 b and Ar2 b Aromatic vinyl polymer block, HD a and HD b is a hydrogenated polymer block of a conjugated diene polymer, Ar2 a The weight average molecular weight (Mw(Ar2 a ))Relative to Ar1 a The weight average molecular weight (Mw(Ar1 a )) ratio (Mw(Ar2 a ) / Mw(Ar1 a )) is 3.0~20, Ar2 b The weight average molecular weight (Mw(Ar2 b ))Relative to Ar1 b The weight average molecular weight (Mw(Ar1 b )) ratio (Mw(Ar2 b ) / Mw(Ar1 b )) is 0.95~1.

05.

2. The cross-linkable polymer composition according to claim 1, wherein The ratio of the aromatic vinyl monomer unit in all repeating units of the polymer component of the hydrogenated block copolymer composition is 20 to 70% by weight.

3. The cross-linkable polymer composition according to claim 1 or 2, wherein The HD in the general formula (A) and the general formula (B) of the hydrogenated block copolymer composition is a and HD b The vinyl bond content of each is 1 to 80 mol %.

4. The cross-linkable polymer composition according to any one of claims 1 to 3, wherein Ar1 in the general formula (A) and the general formula (B) of the hydrogenated block copolymer composition a 、Ar1 b and Ar2 b The weight average molecular weight of HD a and HD b The weight average molecular weight is in the range of 10,000 to 300,000.

5. The cross-linkable polymer composition according to any one of claims 1 to 4, wherein The weight average molecular weight of the polymer components constituting the hydrogenated block copolymer composition is 30,000 to 400,000.

6. The cross-linkable polymer composition according to any one of claims 1 to 5, wherein The polyolefin-based thermoplastic resin C is an ethylene-based resin.

7. The cross-linkable polymer composition according to any one of claims 1 to 6, wherein The ratio of the content of the polyolefin-based thermoplastic resin C to the total content of the hydrogenated block copolymer A and the hydrogenated block copolymer B (C / (A+B)) is 15 / 85 to 50 / 50 in terms of weight ratio.

8. The cross-linkable polymer composition according to any one of claims 1 to 7, wherein The crosslinkable polymer composition further contains a foaming agent.

9. The cross-linkable polymer composition according to claim 8, wherein The foaming agent is a chemical foaming agent. 10 . A cross-linked product obtained by cross-linking the cross-linkable polymer composition according to claim 1 . 11 . A cross-linked foamed product obtained by cross-linking and foaming the cross-linkable polymer composition according to claim 1 .

12. The cross-linked foam according to claim 11, wherein The cross-linked foam is a midsole of a shoe.

13. The cross-linked foam according to claim 11, wherein The cross-linked foam is a buffer material for batteries.

14. The cross-linked foam according to claim 11, wherein The cross-linked foam is a sealing strip.

15. The cross-linked foam according to any one of claims 11 to 14, wherein The apparent density of the cross-linked foam is 0.06 to 0.60 g / cm 3 .

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