Hydrogenated block copolymer composition, method for producing the same, and film

Abstract

Provided is a hydrogenated block copolymer composition that contains a hydrogenated block copolymer A represented by general formula (A) and a hydrogenated block copolymer B represented by general formula (B), wherein the weight ratio (A / B) of the hydrogenated block copolymer A and the hydrogenated block copolymer B is 10 / 90-80 / 20, and the hydrogenation rate of olefins in the polymer components forming the hydrogenated block copolymer composition is 10-100%.　(A): Ar1a-HDa-Ar2a, (B): Ar1b-HDb-Ar2b (in general formula (A) and general formula (B), Ar1a, Ar1b, Ar2a, and Ar2b each represent an aromatic vinyl polymer block, HDa and HDb each represent a hydrogenated polymer block of a conjugated diene polymer, and the ratio (Mw(Ar2a) / Mw(Ar1a)) of the weight average molecular weight (Mw(Ar2a)) of Ar2a with respect to the weight average molecular weight (Mw(Ar1a)) of Ar1a is 2.6-66).

Description

Technical Field

[0001] The present invention relates to a hydrogenated block copolymer composition having a high elastic modulus, a small permanent elongation, and excellent thermal stability, a method for producing the same, and a film obtained by using such a hydrogenated block copolymer composition.

Background Art

[0002] Conventionally, an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer, which is a type of thermoplastic elastomer, has been used as a material for stretchable films used in sanitary products such as disposable diapers and sanitary products because it is particularly rich in elasticity and flexible.

[0003] In such stretchable films, from the viewpoint of being able to be used stably even after long-term use, it is required to have both a high elastic modulus and a small permanent elongation. Further, in such stretchable films, depending on the application, excellent thermal stability is also required.

[0004] For example, Patent Document 1 discloses a resin composition containing a polypropylene-based resin (a) and a hydrogenated block copolymer (b), wherein the hydrogenated block copolymer (b) is a polymer block (A) mainly composed of structural units derived from an aromatic vinyl compound, and a polymer block (B) mainly composed of structural units derived from isoprene, structural units derived from butadiene, or structural units derived from a mixture of isoprene and butadiene, and a hydrogenated product of a block copolymer, and the glass transition temperature of the hydrogenated block copolymer (b) is -50 to -35°C.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] According to the technique of Patent Document 1, by using a hydrogenated block copolymer obtained by hydrogenating a block copolymer, a film excellent in thermal stability can be provided. However, the film obtained by the technique of Patent Document 1 has a problem that the permanent elongation becomes large due to hydrogenation. The present invention has been made in view of such a situation, and an object thereof is to provide a hydrogenated block copolymer composition having a high elastic modulus, a small permanent elongation, and excellent thermal stability. Another object of the present invention is also to provide a method for producing such a hydrogenated block copolymer composition and a film obtained by using such a hydrogenated block copolymer composition.

Means for Solving the Problems

[0007] The inventors of the present invention conducted studies to achieve the above object. As a result, in a hydrogenated block copolymer composition containing two hydrogenated block copolymers having a specific structure, the weight ratio of the two hydrogenated block copolymers having a specific structure is set within a specific range, and the hydrogenation rate of olefin in the polymer component constituting the hydrogenated block copolymer composition is controlled within a specific range, whereby it has been found that a high elastic modulus, a small permanent elongation, and excellent thermal stability can be achieved, and the present invention has been completed.

[0008] That is, according to the present invention, there is provided a hydrogenated block copolymer composition containing 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), wherein the weight ratio (A / B) of the hydrogenated block copolymer A to the hydrogenated block copolymer B is 10 / 90 to 80 / 20, There is provided a hydrogenated block copolymer composition in which the hydrogenation rate of olefin in the polymer component constituting the hydrogenated block copolymer composition is 10 to 100%. Ar1 a -HD a -Ar2a (A) Ar1 b -HD b -Ar2 b (B) (In the above general formula (A) and general formula (B), Ar1 a , Ar2 a , Ar1 b , and Ar2 b are aromatic vinyl polymer blocks, and HD a and HD b are hydrogenated polymer blocks of conjugated diene polymers. The ratio of the weight average molecular weight (Mw(Ar2 a )) of Ar2 a to the weight average molecular weight (Mw(Ar1 a )) of Ar1 a (Mw(Ar2 a ) / Mw(Ar1 a )) is 2.6 to 66.)

[0009] In the hydrogenated block copolymer composition of the present invention, in the above general formula (A) and general formula (B), HD a and HD b are preferably hydrogenated polymer blocks of conjugated diene polymers having a vinyl bond content of 1 to 80 mol%. In the hydrogenated block copolymer composition of the present invention, it is preferable that the proportion of the aromatic vinyl monomer units in all the repeating units of the polymer components of the hydrogenated block copolymer composition is 20 to 70% by weight. In the hydrogenated block copolymer composition of the present invention, in the above general formula (A) and general formula (B), the weight average molecular weights of Ar1 a , Ar1 b , and Ar2 b are each in the range of 2,000 to 40,000, and the weight average molecular weights of HD a and HD b are each preferably in the range of 15,000 to 300,000.

[0010] Also, according to the present invention, there is provided a method for producing the hydrogenated block copolymer composition according to any of the above, which has the following steps (1) to (7). (1): A step of obtaining a solution containing an aromatic vinyl polymer having an active terminal by polymerizing an aromatic vinyl monomer using a polymerization initiator in a solvent (2): A step of obtaining a solution containing an aromatic vinyl-conjugated diene block copolymer having an active terminal by adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having an active terminal obtained in the step (1) and polymerizing the conjugated diene monomer (3): A step of obtaining a solution containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active terminal by 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) and polymerizing the aromatic vinyl monomer (4): A step of adding a polymerization terminator to the solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active terminal obtained in the step (3) in an amount less than 1 molar equivalent to the active terminal, deactivating a part of the active terminal of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active terminal, and obtaining a solution containing a block copolymer B' (5): A step of obtaining a solution containing a block copolymer B' and a block copolymer A' by adding an aromatic vinyl monomer to the solution containing the block copolymer B' obtained in the step (4) and polymerizing the aromatic vinyl monomer (6): A step of obtaining a solution containing a hydrogenated block copolymer B and a hydrogenated block copolymer A by performing a hydrogenation reaction on the solution containing the block copolymer B' and the block copolymer A' obtained in the step (5) (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)

[0011] Alternatively, according to the present invention, there is provided a method for producing a hydrogenated block copolymer composition as described in any of the above, the method for producing a hydrogenated block copolymer composition having the following steps (1a) to (6a). (1a): A step of obtaining a solution containing an aromatic vinyl polymer having an active end by polymerizing an aromatic vinyl monomer using a polymerization initiator in a solvent (2a): A step of obtaining a solution containing an aromatic vinyl-conjugated diene block copolymer having an active end by adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having an active end obtained in the step (1a) and polymerizing the conjugated diene monomer (3a): A step of adding a bifunctional coupling agent to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in the step (2a) in an amount such that the total amount of functional groups is less than 1 molar equivalent with respect to the active end, and coupling a part of the aromatic vinyl-conjugated diene block copolymer having an active end to obtain a solution containing a block copolymer B’ (4a): A step of obtaining a solution containing a block copolymer B’ and a block copolymer A’ by adding an aromatic vinyl monomer to the solution containing the block copolymer B’ obtained in the step (3a) and polymerizing the aromatic vinyl monomer (5a): A step of obtaining a solution containing a hydrogenated block copolymer B and a hydrogenated block copolymer A by subjecting the solution containing the block copolymer B’ and the block copolymer A’ obtained in the step (4a) to a hydrogenation reaction (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)

[0012] Furthermore, according to the present invention, there is provided a film formed by molding the hydrogenated block copolymer composition as described in any of the above. [Effect of the Invention]

[0013] According to the present invention, it is possible to provide a hydrogenated block copolymer composition having a high elastic modulus, a small permanent elongation, and excellent heat stability. Further, according to the present invention, it is possible to provide a method for producing such a hydrogenated block copolymer composition and a film obtained using such a hydrogenated block copolymer composition.

Mode for Carrying Out the Invention

[0014] <Hydrogenated block copolymer composition> The hydrogenated block copolymer 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 weight ratio (A / B) of the hydrogenated block copolymer A to the hydrogenated block copolymer B is 10 / 90 to 80 / 20, and the hydrogenation rate of olefin in the polymer components constituting the hydrogenated block copolymer composition is 10 to 100%. Ar1 a -HD a -Ar2 a (A) Ar1 b -HD b -Ar2 b (B)

[0015] In the above general formula (A), Ar1 a , Ar2 a are aromatic vinyl polymer blocks, and the ratio (Mw(Ar2 a ) / Mw(Ar1 a )) of the weight average molecular weight (Mw(Ar2 a )) of Ar2 to the weight average molecular weight (Mw(Ar1 a )) of Ar1 is 2.6 to 66. Further, HD a ) / Mw(Ar1 a )) is 2.6 to 66. Also, HD a is a hydrogenated polymer block of a conjugated diene polymer.

[0016] Also, in the above general formula (B), Ar1 b , Ar2 b are aromatic vinyl polymer blocks, and HDb is a hydrogenated polymer block of a conjugated diene polymer.

[0017] The aromatic vinyl polymer blocks Ar1 a and Ar2 a of the hydrogenated block copolymer A and the hydrogenated block copolymer B, b Ar1 b and Ar2

[0018] The aromatic vinyl monomer used to form the aromatic vinyl monomer unit is not particularly limited as long as it is an aromatic vinyl compound. Examples of the aromatic vinyl compound include styrene; styrenes substituted with an alkyl group such as α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene; styrenes substituted with a halogen atom such as 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibromostyrene; vinylnaphthalene; and the like. Among these, it is preferable to use styrene. These aromatic vinyl monomers can be used alone or in combination of two or more in each aromatic vinyl polymer block. Also, in each aromatic vinyl polymer block, the same aromatic vinyl monomer may be used, or different aromatic vinyl monomers may be used.

[0019] Also, the aromatic vinyl polymer blocks Ar1 a and Ar2 a that constitute the hydrogenated block copolymer A and the hydrogenated block copolymer B, b Ar1 bmay each contain monomer units other than aromatic vinyl monomer units. Examples of monomers constituting monomer units other than 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 acid anhydride monomers; unsaturated carboxylic acid ester monomers; non-conjugated diene monomers; and the like.

[0020] The content of monomer units other than aromatic vinyl monomer units in each aromatic vinyl polymer block is preferably 20% by weight or less, more preferably 10% by weight or less, and particularly preferably substantially 0% by weight based on the entire aromatic vinyl polymer block.

[0021] The hydrogenated polymer block HD of the conjugated diene polymer that constitutes the hydrogenated block copolymer A and the hydrogenated block copolymer B a , HD b is a polymer block composed of conjugated diene monomer units, and at least a part of the conjugated diene monomer units constituting the polymer block is hydrogenated.

[0022] The conjugated diene monomer used to constitute the conjugated diene monomer units is not particularly limited as long as it is a conjugated diene compound. Examples of conjugated diene compounds include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like. Among these, it is preferable to use 1,3-butadiene and / or isoprene, and it is particularly preferable to use isoprene. By configuring the hydrogenated polymer block of the conjugated diene polymer with isoprene units, a hydrogenated block copolymer composition having excellent flexibility and a smaller permanent elongation can be obtained. These conjugated diene monomers can be used alone or in combination of two or more in each hydrogenated polymer block. Also, the same conjugated diene monomer may be used in each hydrogenated polymer block, or different conjugated diene monomers may be used.

[0023] The hydrogenated polymer block HD of the conjugated diene polymer that constitutes the hydrogenated block copolymer A and the hydrogenated block copolymer B a , HD b may each contain monomer units other than the conjugated diene monomer unit. Examples of the monomer that constitutes the monomer unit other than the conjugated diene monomer unit include aromatic vinyl monomers such as styrene and α-methylstyrene; α,β-unsaturated nitrile monomers; unsaturated carboxylic acid or acid anhydride monomers; unsaturated carboxylic acid ester monomers; non-conjugated diene monomers; and the like.

[0024] The content of the monomer unit other than the conjugated diene monomer unit in each hydrogenated polymer block is preferably 20% by weight or less, more preferably 10% by weight or less, and particularly preferably substantially 0% by weight with respect to the entire conjugated diene polymer block.

[0025] The hydrogenated block copolymer A that constitutes the hydrogenated block copolymer composition is Ar1 a The ratio (Mw(Ar2 a )) of the weight average molecular weight (Mw(Ar2 a )) of Ar2 to the weight average molecular weight (Mw(Ar1 a )) of Ar1 (Mw(Ar2 a ) / Mw(Ar1 a )) is in the range of 2.6 to 66. Therefore, the aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight a , the hydrogenated polymer block HD of the conjugated diene polymer a , and the aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight a are hydrides of an asymmetric aromatic vinyl-conjugated diene-aromatic vinyl block copolymer configured to be connected in this order.

[0026] In the hydrogenated block copolymer A, Mw(Ar2 a ) / Mw(Ar1 a) is in the range of 2.6 to 66, preferably in the range of 4 to 40, more preferably in the range of 4.5 to 35, and even more preferably in the range of 4.5 to 17. Mw(Ar2 a ) / Mw(Ar1 a ) is too small or too large, the permanent elongation of the hydrogenated block copolymer composition will increase. In the present invention, the weight average molecular weight of the polymer or polymer block is determined as a value in terms of polystyrene by measurement with high performance liquid chromatography.

[0027] In addition, the aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight that constitutes the hydrogenated block copolymer A a The weight average molecular weight (Mw(Ar1 a )) is preferably 2,000 to 40,000, more preferably 2,500 to 30,000, even more preferably 3,000 to 10,000, and particularly preferably 3,500 to 6,000. By setting Mw(Ar1 a ) within the above range, the permanent elongation of the hydrogenated block copolymer composition can be made smaller.

[0028] Also, the aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight that constitutes the hydrogenated block copolymer A a The weight average molecular weight (Mw(Ar2 a )) is preferably 5,000 to 250,000, more preferably 8,000 to 120,000, even more preferably 10,000 to 80,000, and particularly preferably 15,000 to 65,000. By setting Mw(Ar2 a ) within the above range, the permanent elongation of the hydrogenated block copolymer composition can be made smaller.

[0029] The hydrogenated polymer block HD of the conjugated diene polymer that constitutes the hydrogenated block copolymer A aThe vinyl bond content (the ratio of 1,2-vinyl bonds and 3,4-vinyl bonds in all conjugated diene monomer units) is usually 1 to 80 mol%, preferably 1 to 50 mol%, more preferably 1 to 50 mol%, even more preferably 1 to 30 mol%, even more preferably 1 to 20 mol%, particularly preferably 2 to 15 mol%, and most preferably 3 to 10 mol%. By setting the vinyl bond content within the above range, the permanent elongation of the resulting block copolymer composition can be made smaller.

[0030] The hydrogenated polymer block HD of the conjugated diene polymer that constitutes 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, even more preferably 15,000 to 150,000, even more preferably 20,000 to 80,000, and particularly preferably 25,000 to 50,000. By setting the weight-average molecular weight (Mw(HD a )) of the hydrogenated polymer block HD within the above range, the hydrogenated block copolymer composition can be made to have a smaller permanent elongation and a higher elastic modulus. a

[0031] The content of the aromatic vinyl monomer unit with respect to all monomer units of the hydrogenated block copolymer A is not particularly limited, but is preferably 10 to 35% by weight, more preferably 12 to 32% by weight, and even more preferably 15 to 30% by weight.

[0032] The weight-average molecular weight of the entire hydrogenated block copolymer A is also 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.

[0033] Further, the hydrogenated block copolymer B that constitutes the hydrogenated block copolymer composition is a conjugated diene polymer block HD bAt both ends of each, two aromatic vinyl polymer blocks Ar1 b , Ar2 b It is a hydrogenated aromatic vinyl-conjugated diene-aromatic vinyl block copolymer composed of the following:

[0034] The two aromatic vinyl polymer blocks Ar1 that constitute the hydrogenated block copolymer B b , Ar2 b Weight average molecular weight (Mw(Ar1 b ), Mw(Ar2 b Mw(Ar1) is preferably 2,000 to 40,000, more preferably 2,500 to 30,000, further preferably 3,000 to 10,000, and particularly preferably 3,500 to 6,000. b ) and Mw(Ar2 b By setting the above range, the permanent elongation of the hydrogenated block copolymer composition can be made smaller. b , Ar2 b Weight average molecular weight (Mw(Ar1 b ), Mw(Ar2 b Within the above range, Ar1 may be equal to or different from each other, but is preferably substantially equal to each other. b Weight average molecular weight (Mw(Ar1 b )) for Ar2 b Weight average molecular weight (Mw(Ar2 b )) ratio (Mw(Ar2 b ) / Mw(Ar1 b )) is preferably in the range of 0.95 to 1.05.

[0035] In addition, these two aromatic vinyl polymer blocks Ar1 b , Ar2 b At least one of the polymer blocks has a weight average molecular weight (Mw(Ar1 b ), Mw(Ar2 b )) is an 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 more preferably substantially equal. For example, Ar1 a The weight average molecular weight (Mw(Ar1 a )) of Ar1 b The weight average molecular weight (Mw(Ar1 b )) ratio (Mw(Ar1 b ) / Mw(Ar1 a )) is in the range of 0.95 to 1.05, or the weight average molecular weight of Ar1 a (Mw(Ar1 a )) of Ar2 b The weight average molecular weight (Mw(Ar2 b )) ratio (Mw(Ar2 b ) / Mw(Ar1 a )) is preferably in the range of 0.95 to 1.05.

[0036] The hydrogenated polymer block HD of the conjugated diene polymer that constitutes the hydrogenated block copolymer B b The vinyl bond content (the ratio occupied by 1,2-vinyl bonds and 3,4-vinyl bonds in all conjugated diene monomer units) is usually 1 to 80 mol%, preferably 1 to 50 mol%, more preferably 1 to 50 mol%, still more preferably 1 to 30 mol%, still more preferably 1 to 20 mol%, particularly preferably 2 to 15 mol%, and most preferably 3 to 10 mol%. By setting the vinyl bond content within the above range, the permanent elongation of the obtained block copolymer composition can be made smaller. Incidentally, the vinyl bond content of the hydrogenated polymer block HD of the conjugated diene polymer that constitutes the hydrogenated block copolymer B b Is preferably substantially equal to the vinyl bond content of the hydrogenated polymer block HD of the conjugated diene polymer that constitutes the hydrogenated block copolymer A a .

[0037] In the production of the hydrogenated block copolymer composition of the present invention, for example, when adopting a production method of a hydrogenated block copolymer composition having the steps of (1a) to (6a) described later, or when adopting a production method using a coupling agent, the hydrogenated polymer block HD of the conjugated diene polymer that constitutes the hydrogenated block copolymer B b may contain the residue of the coupling agent. Specifically, the hydrogenated block copolymer B may be a compound represented by the following formula. Ar1 b -(HD b’ -X-HD b’ ’ )-Ar2 b That is, as shown in the above formula, the hydrogenated polymer block HD of the conjugated diene polymer b is coupled to HD b’ , HD b’ ’ through the residue X of the coupling agent. As the residue X of the coupling agent, residues of bifunctional coupling agents exemplified in the production method of the hydrogenated block copolymer composition having the steps of (1a) to (6a) described later can be mentioned.

[0038] The weight average molecular weight (Mw(HD b )) of the hydrogenated polymer block HD of the conjugated diene polymer that constitutes the hydrogenated block copolymer B b is preferably 10,000 to 300,000, more preferably 15,000 to 300,000, still more preferably 15,000 to 150,000, even more preferably 20,000 to 80,000, and particularly preferably 25,000 to 50,000. By setting the weight average molecular weight (Mw(HD b )) of the hydrogenated polymer block (HD b ) within the above range, the hydrogenated block copolymer composition can have a smaller permanent elongation and a higher elastic modulus.

[0039] The content of the aromatic vinyl monomer unit with respect to all the monomer units of the hydrogenated block copolymer B is not particularly limited, but is preferably 35 to 90% by weight, more preferably 40 to 87% by weight, and still more preferably 43 to 85% by weight.

[0040] 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 still more preferably 30,000 to 70,000.

[0041] 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 hydrogenated block copolymer A and the hydrogenated block copolymer B constituting the hydrogenated block copolymer composition of 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, respectively.

[0042] The weight ratio (A / B) of the hydrogenated block copolymer A and the hydrogenated block copolymer B contained in the hydrogenated block copolymer composition of the present invention is preferably 10 / 90 to 80 / 20, more preferably 12 / 88 to 60 / 40, and still more preferably 15 / 85 to 50 / 50. With such a ratio, by containing the hydrogenated block copolymer A and the hydrogenated block copolymer B, the hydrogenated block copolymer composition can have both a high elastic modulus and a small permanent elongation. If the weight ratio (A / B) is too small, the elastic modulus of the hydrogenated block copolymer composition will be insufficient, and if the weight ratio (A / B) is too large, the permanent elongation of the hydrogenated block copolymer composition will be too large.

[0043] In addition, in the polymer component constituting the hydrogenated block copolymer composition of the present invention, the hydrogenation rate of olefin is in the range of 10 to 100%. Here, the hydrogenation rate of olefin refers to the hydrogenation rate of olefin in all polymer components constituting the hydrogenated block copolymer composition. Specifically, it is the ratio (mol%) of the hydrogenated ones among all non-aromatic carbon-carbon double bonds contained in the polymer component before hydrogenation. As a result of intensive studies by the present inventors, the hydrogenated block copolymer composition contains the hydrogenated block copolymer A represented by the general formula (A) and the hydrogenated block copolymer B represented by the general formula (B) in a specific weight ratio, and by setting the hydrogenation rate of olefin in the hydrogenated block copolymer composition within the above range, it has been found that excellent thermal stability can be achieved while maintaining a high elastic modulus and a small permanent elongation. In particular, according to the present invention, by containing the hydrogenated block copolymer A represented by the general formula (A) and the hydrogenated block copolymer B represented by the general formula (B) in a specific weight ratio, the effect of improving thermal stability by hydrogenation can be obtained while effectively suppressing the increase in permanent elongation due to hydrogenation. Thereby, the hydrogenated block copolymer composition can have a high elastic modulus, a small permanent elongation, and excellent thermal stability.

[0044] The hydrogenation rate of olefin in the polymer component constituting the hydrogenated block copolymer composition of the present invention may be in the range of 10 to 100%, preferably 30 to 100%, more preferably 70 to 100%, and still more preferably 90 to 100%. If the hydrogenation rate of olefin is too low, the thermal stability of the hydrogenated block copolymer composition will be insufficient.

[0045] In addition, for the hydrogenated block copolymer composition of the present invention, the hydrogenation rate of the olefin only needs to be within the above range. However, in the polymer components constituting the hydrogenated block copolymer composition, the iodine value is preferably in the range of 0 to 300 gI2 / 100 g, more preferably in the range of 0 to 150 gI2 / 100 g, even more preferably in the range of 0 to 125 gI2 / 100 g, even more preferably in the range of 0 to 90 gI2 / 100 g, and particularly preferably in the range of 0 to 30 gI2 / 100 g. If the iodine value is too high, the thermal stability will be poor.

[0046] The hydrogenated block copolymer composition of the present invention may contain only the hydrogenated block copolymer A and the hydrogenated block copolymer B as polymer components. However, as long as the effects of the present invention are not impaired, it may contain polymer components other than the hydrogenated block copolymer A and the hydrogenated block copolymer B.

[0047] Examples of the polymer components other than the hydrogenated block copolymer A and the hydrogenated block copolymer B that can be included in the hydrogenated block copolymer composition of the present invention include aromatic vinyl-conjugated diene-aromatic vinyl block copolymers, aromatic vinyl-conjugated diene block copolymers, aromatic vinyl homopolymers, conjugated diene homopolymers, aromatic vinyl-conjugated diene random copolymers, and branched polymers thereof, other than the hydrogenated block copolymer A and the hydrogenated block copolymer B; thermoplastic elastomers such as polyurethane-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and polyester-based thermoplastic elastomers; thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, and polyphenylene ether; and the like.

[0048] In the hydrogenated block copolymer composition of the present invention, the content of the polymer components other than the hydrogenated block copolymer A and the hydrogenated block copolymer B is preferably 20% by weight or less, more preferably 10% by weight or less, based on the total polymer components.

[0049] In the hydrogenated block copolymer composition of the present invention, the proportion of aromatic vinyl monomer units (hereinafter sometimes referred to as "total aromatic vinyl monomer unit content") in the entire polymer component (all monomer units constituting the polymer component) in the hydrogenated block copolymer composition is preferably 25 to 70% by weight, more preferably 30 to 60% by weight, and still more preferably 32 to 50% by weight. By setting the total aromatic vinyl monomer unit content within the above range, the hydrogenated block copolymer composition can have a smaller permanent elongation and a higher elastic modulus. The total aromatic vinyl monomer unit content can be easily adjusted by considering the content of aromatic vinyl monomer units in each of the hydrogenated block copolymer A, hydrogenated block copolymer B, and other polymer components constituting the hydrogenated block copolymer composition and adjusting their blending amounts.

[0050] When all the polymer components constituting the hydrogenated block copolymer composition are composed only of aromatic vinyl monomer units and conjugated diene monomer units, according to the method described in Rubber Chem. Technol., 45, 1295 (1972), the polymer components in the hydrogenated block copolymer composition are ozonolyzed and then reduced with lithium aluminum hydride, so that the conjugated diene monomer unit portion (including the hydrogenated portion) is decomposed and only the aromatic vinyl monomer unit portion can be taken out. Therefore, the total aromatic vinyl monomer unit content can be easily measured.

[0051] The weight average molecular weight of the entire polymer component constituting the hydrogenated block copolymer composition of the present invention is not particularly limited, but is preferably 30,000 to 400,000, more preferably 35,000 to 100,000, and still more preferably 40,000 to 80,000.

[0052] In addition, 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 component constituting the hydrogenated block copolymer composition of the present invention is not particularly limited, but is preferably from 1.01 to 10, more preferably from 1.02 to 5, still more preferably from 1.03 to 3, even more preferably from 1.03 to 2, and particularly preferably from 1.02 to 1.5.

[0053] The hydrogenated block copolymer composition of the present invention may contain components other than the polymer component, if necessary. Examples of the components other than the polymer component include antioxidants, softeners, tackifiers, antibacterial agents, light stabilizers, ultraviolet absorbers, dyes, lubricants, crosslinking agents, crosslinking accelerators, and the like.

[0054] Examples of the antioxidant include hindered phenol compounds such as pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,6-di-t-butyl-p-cresol, and di-t-butyl-4-methylphenol; thiodicarboxylate esters such as dilauryl thiodipropionate; phosphites such as tris(nonylphenyl)phosphite; and the like. The antioxidant may be used alone or in combination of two or more. The content of the antioxidant is not particularly limited, but is preferably 10 parts by weight or less, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the hydrogenated block copolymer composition.

[0055] The method for producing the hydrogenated block copolymer composition of the present invention is not particularly limited. For example, according to the conventional production methods and hydrogenation methods of block copolymers, the hydrogenated block copolymer A and the hydrogenated block copolymer B are produced separately, and if necessary, other polymer components and various additives are blended, and then they are mixed according to conventional methods such as kneading or solution mixing. On the other hand, in the present invention, from the viewpoint that the hydrogenated block copolymer composition can be produced with high productivity, the production method of the hydrogenated block copolymer composition of the present invention described below is preferred.

[0056] That is, the method for producing the hydrogenated block copolymer composition of the present invention includes the following steps (1) to (7). (1): A step of obtaining a solution containing an aromatic vinyl polymer having an active end by polymerizing an aromatic vinyl monomer using a polymerization initiator in a solvent (2): A step of adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having an active end obtained in the step (1) and polymerizing the conjugated diene monomer to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having an active end (3): A step of adding an aromatic vinyl monomer to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in the step (2) and polymerizing the aromatic vinyl monomer to obtain a solution containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end (4): A step of adding a polymerization terminator to the solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end obtained in the step (3) in an amount less than 1 molar equivalent to the active end, deactivating a part of the active end of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end, and obtaining a solution containing a block copolymer B' (5): A step of adding an aromatic vinyl monomer to the solution containing the block copolymer B' obtained in the step (4) and polymerizing the aromatic vinyl monomer to obtain a solution containing the block copolymer B' and the block copolymer A' (6): A step of performing a hydrogenation reaction on the solution containing the block copolymer B' and the block copolymer A' obtained in the step (5) to obtain a solution containing a hydrogenated block copolymer B and a hydrogenated block copolymer A (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)

[0057] <Step (1)> In the method for producing the hydrogenated block copolymer composition of the present invention, first, in step (1), an aromatic vinyl monomer is polymerized using a polymerization initiator in a solvent to obtain a solution containing an aromatic vinyl polymer having an active terminal.

[0058] As the polymerization initiator, a polymerization initiator known to have anionic polymerization activity with respect to the aromatic vinyl monomer and the conjugated diene monomer can be used. Examples of the polymerization initiator include organic alkali metal compounds, organic alkaline earth metal compounds, and organic lanthanoid series rare earth metal compounds.

[0059] As the organic alkali metal compound, an organic lithium compound having one or more lithium atoms in the molecule is particularly preferably used. Specific examples of the organic alkali metal compound include organic monolithium compounds such as ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, stilbenelithium, dialkylaminolithium, diphenylaminolithium, and ditrimethylsilylaminolithium; organic dilithium compounds such as methylenedilithium, tetramethylenedilithium, hexamethylenedilithium, isoprenyldilithium, and 1,4-dithio-ethylcyclohexane; and further organic trilithium compounds such as 1,3,5-trilithiobenzene. Among these, organic monolithium compounds are particularly preferably used.

[0060] Examples of the organic alkaline earth metal compound include n-butylmagnesium bromide, n-hexylmagnesium bromide, ethoxycalcium, calcium stearate, t-butoxystrontium, ethoxy barium, isopropoxy barium, ethylmercaptopotassium, t-butoxy barium, phenoxy barium, diethylaminobarium, barium stearate, and ethylbarium.

[0061] In addition to the above, composite catalysts composed of lanthanoid series rare earth metal compounds containing neodymium, samarium, gadolinium, etc., alkylaluminum, alkylaluminum halide, alkylaluminum hydride, or metallocene catalysts containing titanium, vanadium, samarium, gadolinium, etc., which become homogeneous in an organic solvent and have living polymerizability, can also be used.

[0062] The above polymerization initiator may be used alone or in combination of two or more. The amount of the polymerization initiator used may be determined according to the molecular weight of each target block copolymer and is not particularly limited. However, per 100 g of all monomers used in the polymerization, it is preferably 0.01 to 20 mmol, more preferably 0.05 to 15 mmol, and even more preferably 0.1 to 10 mmol.

[0063] The solvent used for the polymerization may be any one that is inert to the polymerization initiator and is not particularly limited. For example, chain hydrocarbon solvents, cyclic hydrocarbon solvents, or mixed solvents thereof can be mentioned. Examples of the chain hydrocarbon solvent 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, neo-pentane, and n-hexane. Examples of the cyclic hydrocarbon solvent include aromatic compounds such as benzene, toluene, and xylene; alicyclic hydrocarbon compounds such as cyclopentane and cyclohexane. These solvents may be used alone or in combination of two or more.

[0064] The amount of the solvent used is not particularly limited, but it is preferably an amount such that the concentration of the total block copolymer in the solution after the polymerization reaction is 5 to 60% by weight, more preferably 10 to 55% by weight, and even more preferably 20 to 50% by weight.

[0065] In addition, when producing the hydrogenated block copolymer composition, a Lewis base compound may be added to the reaction system in order to control the structure of each polymer block of each block copolymer. Examples of the Lewis base compound include ethers such as tetrahydrofuran, diethyl ether, dioxane, dibutyl ether, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, and diethylene glycol dibutyl ether; tertiary amines such as tetramethylethylenediamine, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxides such as potassium-t-amyl oxide and potassium-t-butoxide; phosphines such as triphenylphosphine; and the like. These Lewis base compounds may be used alone or in combination of two or more.

[0066] When producing the hydrogenated block copolymer composition, the timing of adding the Lewis base compound is not particularly limited and may be appropriately determined according to the structure of the target block copolymer. For example, it may be added in advance before the start of polymerization, or may be added after polymerizing some of the polymer blocks. Further, it may be added in advance before the start of polymerization and further added after polymerizing some of the polymer blocks.

[0067] The polymerization reaction temperature is preferably 10 to 150 °C, more preferably 30 to 130 °C, still more preferably 40 to 90 °C, and the polymerization time is preferably within 48 hours, more preferably 0.5 to 10 hours. The polymerization pressure may be within a range sufficient to maintain the monomers and the solvent in the liquid phase at the polymerization temperature and is not particularly limited.

[0068] Under the above conditions, by polymerizing an aromatic vinyl monomer using a polymerization initiator in a solvent, a solution containing an aromatic vinyl polymer having a living end can be obtained. In this way, the aromatic vinyl polymer having a living end obtained in step (1) is an aromatic vinyl polymer block Ar1 having a relatively small weight average molecular weight of the hydrogenated block copolymer A, which constitutes the hydrogenated block copolymer composition. a and the aromatic vinyl polymer block Ar1 of the hydrogenated block copolymer B b , Ar2 b either one (that is, Ar1 b or Ar2 b ). Therefore, each polymerization condition including the amount of the aromatic vinyl monomer in step (1) may be determined according to the target weight average molecular weight of these polymer blocks and the like.

[0069] <Step (2)> Next, in step (2), a conjugated diene monomer is added to the solution containing the aromatic vinyl polymer having a living end obtained in step (1) above, and the conjugated diene monomer is polymerized to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having a living end.

[0070] According to step (2), by adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having a living end obtained in step (1) above, a conjugated diene polymer chain is formed starting from the living end, whereby a solution containing an aromatic vinyl-conjugated diene block copolymer having a living end can be obtained.

[0071] The conjugated diene polymer chain formed in step (2) (the conjugated diene block that constitutes the aromatic vinyl-conjugated diene block copolymer having a living end obtained in step (2)) is 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 bIt will be configured as such. Therefore, each polymerization condition including the amount of the conjugated diene polymer in step (2) may be determined according to the target weight-average molecular weight, vinyl bond content, etc. of these polymer blocks (for example, the polymerization conditions may be determined within the range described in step (1) above).

[0072] <Step (3)> Next, in step (3), an aromatic vinyl monomer is added to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in step (2) above, and the aromatic vinyl monomer is polymerized to obtain a solution containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end.

[0073] According to step (3), by adding an aromatic vinyl monomer to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in step (2) above, starting from the active end, an aromatic vinyl polymer chain is formed, whereby a solution containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end can be obtained.

[0074] 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 end obtained in step (3)) is the aromatic vinyl polymer block Ar1 of the hydrogenated block copolymer B b , Ar2 b One of them (that is, Ar1 b or Ar2 b is a block different from the block formed in step (1). For example, when Ar1 b is formed in step (1), Ar2 bwill apply. It is to form (). Therefore, each polymerization condition including the amount of the aromatic vinyl monomer in step (3) may be determined according to the target weight average molecular weight of such a polymer block (for example, the polymerization conditions may be determined within the range described in step (1) above).

[0075] <Step (4)> Next, in step (4), a polymerization terminator is added to the solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end obtained in step (3) in an amount less than 1 molar equivalent to the active end, and a part of the active ends of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end is deactivated to obtain a solution containing block copolymer B'.

[0076] The block copolymer B' obtained in step (4) is a block copolymer before hydrogenation for obtaining the hydrogenated block copolymer B.

[0077] The polymerization terminator may be any compound that can react with the active end to deactivate the active end and does not react with another active end after reacting with one active end, and is not particularly limited, but is preferably a compound that does not contain a halogen atom. Among them, a polymerization terminator that generates a metal alkoxide, a metal aryloxide, or a metal hydroxide when reacting with the active end is particularly preferred. Specific examples of the polymerization terminator include water; monohydric alcohols such as methanol and ethanol; monohydric phenols such as phenol and cresol; and the like.

[0078] The amount of the polymerization terminator used may be determined according to the ratio of the hydrogenated block copolymer A and the hydrogenated block copolymer B constituting the hydrogenated block copolymer composition, and is not particularly limited as long as it is less than 1 molar equivalent to the active end of the polymer. However, the amount of the polymerization terminator used is preferably in the range of 0.18 to 0.91 molar equivalent, and more preferably in the range of 0.35 to 0.80 molar equivalent, relative to the active end of the polymer.

[0079] As described above, according to step (4), to a solution containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having a living end, a polymerization terminator is added in an amount less than 1 molar equivalent to the living end, whereby the living ends of some of the copolymers in the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having a living end are deactivated, and the copolymer whose living end has been deactivated becomes a block copolymer B' before hydrogenation for constituting the hydrogenated block copolymer B. And a part of the remaining aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having a living end that did not react with the polymerization terminator remains in the solution in a state maintaining the living end without reaction.

[0080] <Step (5)> Next, in step (5), an aromatic vinyl monomer is added to the solution containing the block copolymer B' obtained in the above step (4), and the aromatic vinyl monomer is polymerized to obtain a solution containing the block copolymer B' and the block copolymer A'.

[0081] According to step (5), when an aromatic vinyl monomer is added to the solution obtained in the above step (4), an aromatic vinyl monomer further polymerizes from the aromatic vinyl polymer chain on the side having the living end of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having a living end that remained without reacting with the polymerization terminator, and the aromatic vinyl polymer chain is extended, whereby the block copolymer A' is obtained. 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.

[0082] At this time, in step (5), the extended aromatic vinyl polymer chain is an aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight of the hydrogenated block copolymer A that constitutes the hydrogenated block copolymer composition. aIt will be configured. Therefore, each polymerization condition including the amount of the aromatic vinyl monomer in step (5) may be determined according to the target weight average molecular weight of such an aromatic vinyl polymer block Ar2 a and the like (for example, the polymerization conditions may be determined within the range described in step (1) above).

[0083] <Step (6)> Next, in step (6), a hydrogenation reaction is carried out on the solution containing the block copolymer B' and the block copolymer A' obtained in step (5) above to obtain a solution containing the hydrogenated block copolymer B and the hydrogenated block copolymer A.

[0084] The method for carrying out the hydrogenation reaction on the solution containing the block copolymer B' and the block copolymer A' is not particularly limited. For example, in the presence of a hydrogenation catalyst, the solution containing the block copolymer B' and the block copolymer A' is brought into contact with hydrogen, and the like can be mentioned.

[0085] The hydrogenation catalyst is not particularly limited. For example, a supported heterogeneous catalyst in which a metal such as Ni, Pt, Pd, Ru, etc. is supported on a carrier such as carbon, silica, alumina, diatomaceous earth, etc., and a Ziegler catalyst using an organic salt or acetylacetone salt of Ni, Co, Fe, Cr, etc. and a reducing agent such as organic Al; an organometallic complex catalyst such as an organometallic compound of Ru, Rh, etc.; a homogeneous catalyst using an organic Li, organic Al, organic Mg, etc. as a reducing agent for a titanocene compound; and the like can be mentioned. Among these, the Ziegler catalyst is preferable.

[0086] The hydrogenation reaction can be carried out, for example, according to the methods disclosed in Japanese Patent Publication No. Sho 42-8704, Japanese Patent Publication No. Sho 43-6636, Japanese Patent Laid-Open No. Sho 59-133203, Japanese Patent Laid-Open No. Sho 60-220147, etc.

[0087] The conditions for the hydrogenation reaction may 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, more preferably 30 to 150 °C. Also, the pressure of hydrogen used in the hydrogenation reaction is preferably 0.1 to 15 MPa, more preferably 0.2 to 10 MPa, still more preferably 0.3 to 5 MPa. The hydrogenation reaction time is preferably 3 minutes to 10 hours, more preferably 10 minutes to 5 hours. Note that the hydrogenation reaction may be any of a batch process, a continuous process, or a combination thereof.

[0088] <Step (7)> 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 the above step (6).

[0089] The recovery method may follow a conventional method and is not particularly limited. For example, after the reaction is completed, if necessary, a polymerization terminator is added to deactivate the active ends of the polymer having active ends, and if necessary, additives such as antioxidants are added, and then known solvent methods such as a drying method or steam stripping are directly applied to the solution to recover the target hydrogenated block copolymer composition. At this time, the above-mentioned ones can be used as the polymerization terminator.

[0090] When the hydrogenated block copolymer composition is recovered as a slurry by steam stripping or the like, dehydration is performed by using any dehydrator such as an extruder-type squeezer to recover a clam-shaped hydrogenated block copolymer composition, and it is preferable to further dry the obtained clam using any dryer such as a band dryer or an expansion extrusion dryer. Also, the hydrogenated block copolymer composition thus obtained may be processed into a pellet shape or the like according to a conventional method and then used.

[0091] The solid (pellet-like, crumb-like, 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 shelf dryer, a shelf 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 achieved, and may be set according to the water content to be reduced, the type of dryer, etc. Usually, the drying temperature is set in the range of 40 to 90 °C and the drying time is set in the range of 1 to 24 hours.

[0092] According to the method for producing the hydrogenated block copolymer composition of the present invention described above, since the hydrogenated block copolymer A and the hydrogenated block copolymer B can be continuously obtained in the same reaction vessel, compared with the case where each hydrogenated block copolymer is produced and mixed individually, the target hydrogenated block copolymer composition can be obtained with excellent productivity.

[0093] And since the hydrogenated block copolymer composition of the present invention has a high elastic modulus, a small permanent elongation, and excellent thermal stability, taking advantage of such characteristics, it can be suitably used for various applications. For example, the hydrogenated block copolymer composition of the present invention can be suitably used for applications such as stretch films, gloves, elastic bands, condoms, various rolls for OA equipment, office use, etc., anti-vibration sheets for electric and electronic equipment, anti-vibration rubbers, impact absorption sheets, impact buffer films / sheets, vibration damping sheets for housing, vibration damping damper materials, etc. for molding material applications, pressure-sensitive adhesives for pressure-sensitive tapes, pressure-sensitive adhesive sheets, pressure-sensitive adhesive labels, pressure-sensitive adhesive layers for surface protection films, dust collection rollers, etc., adhesive applications for sanitary products and bookbinding, and elastic fiber applications for clothing, sports goods, etc.

[0094] When the hydrogenated block copolymer composition of the present invention is made into a film such as a stretch film, as a method for forming the film, conventionally known forming methods such as melt forming and solution forming can be adopted without particular limitation. However, from the viewpoint of productivity, melt forming is particularly suitable.

[0095] When obtaining a film by melt-molding the hydrogenated block copolymer composition of the present invention, various melt-molding methods can be employed. From the viewpoint of obtaining a smooth film with particularly good productivity, extrusion molding (melt extrusion molding) is suitable, and among them, extrusion molding using a T-die is particularly suitable. As a specific example of extrusion molding using a T-die, a method of extruding the hydrogenated block copolymer composition melted at a temperature of 150 to 250°C from a T-die attached to a single-screw extruder or a twin-screw extruder and winding it up while cooling with a take-up roll can be mentioned. When cooling with a take-up roll, the film may be stretched. Further, when winding up the film, it may be formed into a film while coating the melt of the hydrogenated block copolymer composition on a base material made of polyethylene terephthalate, polyethylene, polypropylene, non-woven fabric or release paper, or it may be formed into a film by sandwiching the melt of the hydrogenated block copolymer composition with these base materials.

[0096] The obtained film may be used in the form integrated with the base material or peeled off from the base material. The thickness of the film is adjusted according to the application. For example, when the film is for sanitary products such as paper diapers and sanitary products, it is preferably 0.01 to 5 mm, more preferably 0.03 to 1 mm, and still more preferably 0.05 to 0.5 mm.

[0097] In addition, when producing the hydrogenated block copolymer composition of the present invention, instead of the above-described production method (production method including steps (1) to (7)), a production method of a hydrogenated block copolymer composition having the following steps (1a) to (6a) may be adopted. (1a): A step of obtaining a solution containing an aromatic vinyl polymer having an active end by polymerizing an aromatic vinyl monomer using a polymerization initiator in a solvent (2a): A step of obtaining a solution containing an aromatic vinyl-conjugated diene block copolymer having an active end by adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having an active end obtained in the step (1a) and polymerizing the conjugated diene monomer (3a): To a solution containing an aromatic vinyl-conjugated diene block copolymer having an active end obtained in the above step (2a), a bifunctional coupling agent is added in an amount such that the total amount of functional groups is less than 1 molar equivalent with respect to the active end, and a part of the aromatic vinyl-conjugated diene block copolymer having an active end is coupled to obtain a solution containing a block copolymer B'. (4a): To the solution containing the block copolymer B' obtained in the above step (3a), an aromatic vinyl monomer is added and polymerized to obtain a solution containing a block copolymer B' and a block copolymer A'. (5a): For the solution containing the block copolymer B' and the block copolymer A' obtained in the above step (4a), a hydrogenation reaction is carried out to obtain a solution containing a hydrogenated block copolymer B and a hydrogenated block copolymer A. (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 above step (5a).

[0098] <Steps (1a) and (2a)> Steps (1a) and (2a) are the same as the above-described steps (1) and (2), and the same conditions can be adopted.

[0099] <Step (3a)> In step (3a), to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in the above step (2a), a bifunctional coupling agent is added in an amount such that the total amount of functional groups is less than 1 molar equivalent with respect to the active end, and a part of the aromatic vinyl-conjugated diene block copolymer having an active end is coupled to obtain a solution containing a block copolymer B'.

[0100] The block copolymer B' obtained in step (3a) is a pre-hydrogenation block copolymer for obtaining a hydrogenated block copolymer B.

[0101] The bifunctional coupling agent may be any one having two functional groups that react with the active ends, and is not particularly limited. For example, bifunctional halogenated silanes such as dichlorosilane, monomethyldichlorosilane, and dimethyldichlorosilane; bifunctional halogenated alkanes such as dichloroethane, dibromoethane, methylene chloride, and dibromomethane; bifunctional halogenated stannanes such as dichlorotin, monomethyldichlorotin, dimethyldichlorotin, monoethyldichlorotin, diethyldichlorotin, monobutyldichlorotin, and dibutyldichlorotin.

[0102] The amount of the bifunctional coupling agent used may be determined according to the ratio of the hydrogenated block copolymer A and the hydrogenated block copolymer B constituting the hydrogenated block copolymer composition.

[0103] As described above, according to step (3a), in a solution containing an aromatic vinyl-conjugated diene block copolymer having active ends, a bifunctional coupling agent is added in an amount such that the total amount of functional groups is less than 1 molar equivalent with respect to the active ends. Thus, among the aromatic vinyl-conjugated diene block copolymers having active ends, some of the copolymers are coupled to form a pre-hydrogenation block copolymer B' for constituting the hydrogenated block copolymer B. And the remaining part of the aromatic vinyl-conjugated diene block copolymer having active ends that did not react with the bifunctional coupling agent remains in the solution in a state maintaining the active ends without reaction.

[0104] <Step (4a)> Next, in step (4a), an aromatic vinyl monomer is added to the solution containing the block copolymer B' obtained in the above step (3a), and the aromatic vinyl monomer is polymerized to obtain a solution containing the block copolymer B' and the block copolymer A'.

[0105] According to step (4a), when an aromatic vinyl monomer is added to the solution obtained in step (3a), the aromatic vinyl monomer polymerizes from the active ends of the aromatic vinyl-conjugated diene block copolymer having active ends that remained without reacting with the bifunctional coupling agent, and an aromatic vinyl polymer chain is formed. Thereby, block copolymer A' is obtained. Note that block copolymer A' is a block copolymer before hydrogenation for obtaining hydrogenated block copolymer A.

[0106] At this time, in step (4a), the formed aromatic vinyl polymer chain constitutes the aromatic vinyl polymer block Ar2 having a relatively large weight average molecular weight of hydrogenated block copolymer A that constitutes the hydrogenated block copolymer composition. a Therefore, each polymerization condition including the amount of the aromatic vinyl monomer in step (4a) may be determined according to the target weight average molecular weight and the like of such an aromatic vinyl polymer block Ar2 a (For example, the polymerization conditions may be determined within the range described in step (1) above.)

[0107] <Steps (5a) and (6a)> Then, using the solution containing block copolymer B' and block copolymer A' obtained in step (4a), through the operations in steps (5a) and (6a) described above, the hydrogenated block copolymer composition of the present invention can be obtained. Note that steps (5a) and (6a) described above are the same as steps (6) and (7) described above, and the same conditions can be adopted.

Examples

[0108] Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited only to these examples. Note that "parts" and "%" are based on mass unless otherwise specified. The test methods performed in these examples and comparative examples are as follows.

[0109] [Weight average molecular weight] It was determined as the polystyrene equivalent molecular weight by high performance liquid chromatography using tetrahydrofuran with a flow rate of 0.35 ml / min as the carrier. The apparatus was HLC8320 manufactured by Tosoh Corporation, the column was a combination of three Shodex (registered trademark) KF-404HQ columns manufactured by Showa Denko K.K. (column temperature: 40 °C), the detectors used were a differential refractometer and an ultraviolet detector, and the molecular weight calibration was carried out at 12 points using standard polystyrenes (from 500 to 3 million) manufactured by Polymer Laboratories.

[0110] It was determined from the area ratio of the peaks corresponding to each block copolymer in the chromatogram obtained by the above high performance liquid chromatography.

[0111] According to the method described in Rubber Chem.Technol.,45,1295(1972), the isoprene polymer block of the (hydrogenated) block copolymer was decomposed by reacting the (hydrogenated) block copolymer with ozone and reducing it with lithium aluminum hydride. ​​Specifically, the following procedure was carried out. That is, 300 mg of the sample was dissolved in 100 ml of dichloromethane treated with molecular sieve in a reaction vessel. The reaction vessel was placed in a cooling bath at -25°C, and then ozone generated by an ozone generator was introduced while flowing oxygen into the reaction vessel at a flow rate of 170 ml / min. After 30 minutes had elapsed since the start of the reaction, it was confirmed that the reaction was complete by introducing the gas flowing out of the reaction vessel into an aqueous potassium iodide solution. Next, 50 ml of diethyl ether and 470 mg of lithium aluminum hydride were charged into another reaction vessel that had been purged with nitrogen, and while cooling the reaction vessel with ice water, the solution that had reacted with ozone was slowly dropped into this reaction vessel. Then, the reaction vessel was placed in a water bath, the temperature was gradually raised, and it was refluxed at 40°C for 30 minutes. Thereafter, while stirring the solution, dilute hydrochloric acid was slowly dropped into the reaction vessel, and the dropping was continued until almost no generation of hydrogen was observed. After this reaction, the solid product formed in the solution was filtered off, and the solid product was extracted with 100 ml of diethyl ether for 10 minutes. The extract and the filtrate obtained upon filtration were combined, and the solvent was distilled off to obtain a solid sample. Regarding the sample thus obtained, the weight-average molecular weight was measured according to the above-described method for measuring the weight-average molecular weight, and the value was taken as the weight-average molecular weight of the styrene polymer block.

[0112] [Weight-average molecular weight of the (hydrogenated) isoprene polymer block of the (hydrogenated) block copolymer] From the weight-average molecular weight of the (hydrogenated) block copolymer determined as described above, the weight-average molecular weight of the corresponding styrene polymer block was subtracted, and based on the calculated value, the weight-average molecular weight of the (hydrogenated) isoprene polymer block was determined.

[0113] [Styrene unit content of the (hydrogenated) block copolymer] It was determined based on the detection intensity ratio between the differential refractometer and the ultraviolet detector in the above measurement by high-performance liquid chromatography. In addition, copolymers having different styrene unit contents were prepared in advance, and a calibration curve was created using them.

[0114] [Styrene unit content of the (hydrogenated) block copolymer composition as a whole] Determined based on the measurement of proton NMR.

[0115] [Vinyl bond content of the (hydrogenated) isoprene polymer block] Determined based on the measurement of proton NMR.

[0116] [Olefin hydrogenation rate (%) of the (hydrogenated) block copolymer composition] 1 By H-NMR spectrum measurement, for each of the block copolymer composition before hydrogenation and the hydrogenated block copolymer composition after hydrogenation, the amount of olefin was determined, and the olefin hydrogenation rate (%) was calculated based on the difference in the amount of olefin before and after hydrogenation. 1 In the H-NMR spectrum measurement, deuterated chloroform was used as the solvent, and a JMN-AL series AL400 (manufactured by JEOL) was used as the NMR measuring device. Also, in this example and the comparative example, since both the block copolymer composition before hydrogenation and the hydrogenated block copolymer composition after hydrogenation contained only isoprene units as the units of the monomer derived from olefin, when measuring, the hydrogenation rate of isoprene was determined and used as the olefin hydrogenation rate.

[0117] [Iodine value of the (hydrogenated) block copolymer composition] Measured in accordance with JIS K0070.

[0118] [Tensile modulus of the film] From the film of the (hydrogenated) block copolymer composition to be measured, two films with a width of 25 mm were cut out, and using these as samples, the measurement was carried out with the pulling direction aligned with the direction perpendicular to the melt flow during molding. The measurement procedure is as follows. That is, the sample was fixed to a tensilon universal testing machine (manufactured by ORIENTEC, "RTC-1210") without tension with a chuck distance of 40 mm. Then, the sample was stretched to 200% at a speed of 300 mm / min, and then the sample was returned to the initial chuck distance at a speed of 300 mm / min. Furthermore, the sample was stretched to 200% again at the same speed and then returned to the initial chuck distance at the same speed again. The tensile stress at 50% elongation during the process of returning to the initial chuck distance for the second time was measured, and the tensile modulus of the stretchable film at 50% elongation was determined. It should be noted that the higher the tensile modulus, the higher the elastic modulus can be said to be.

[0119] Permanent elongation of film Regarding the film of the (hydrogenated) block copolymer composition serving as the sample, in accordance with ASTM 412, using the above-mentioned tensilon universal testing machine, the measurement was carried out with the pulling direction aligned with the direction perpendicular to the melt flow during molding. Specifically, Die A was used for the sample shape, the distance between the gauge marks before stretching was set to 40 mm, the film was stretched at an elongation rate of 100%, held in that state for 10 minutes, then suddenly shrunk without bouncing back, left for 10 minutes, the distance between the gauge marks was measured, and the permanent elongation was determined based on the following formula. Permanent elongation (%) = (L1 - L0) / L0 × 100 L0: Distance between gauge marks before elongation (mm) L1: Distance between gauge marks after shrinking and leaving for 10 minutes (mm)

[0120] Thermal stability Regarding the film of the (hydrogenated) block copolymer composition serving as the sample, a thermal degradation test (170 °C × 60 minutes; in the presence of air) was carried out, and the melt viscosity was measured before and after the thermal degradation test, and the viscosity retention rate was determined by the following formula. The higher the viscosity retention rate, the better the thermal stability can be judged. Viscosity retention rate (%) = (melt viscosity after thermal degradation test / melt viscosity before thermal degradation test) × 100 The measurement of the melt viscosity was carried out using a flow tester CFT-500C (manufactured by Shimadzu Corporation), at a temperature of 180 °C and a load of 100 kgf / cm 2It was measured under the condition of a die shape of 1 mmφ × 10 mm.

[0121] [Example 1] (1) Production of the block copolymer composition before hydrogenation To a pressure-resistant reactor, 56.6 kg of cyclohexane, 505 mmol of dibutyl ether, and 1.22 kg of styrene were added. While stirring the whole volume at 40 °C, 270.6 mmol of n-butyllithium (1.6 M solution) was added. After the addition was completed, the temperature was raised to 50 °C and a polymerization reaction was carried out for 1 hour (the first stage of polymerization). The polymerization conversion rate of styrene at this time was 100% by weight.

[0122] Subsequently, while controlling the temperature to maintain 50 - 60 °C, 6.49 kg of isoprene was continuously added to the reactor over 1 hour. After the addition of isoprene was completed, a polymerization reaction was carried out for another 1 hour (the second stage of polymerization). The polymerization conversion rate of isoprene at this time was 100%.

[0123] Next, while controlling the temperature to maintain 50 - 60 °C, 1.22 kg of styrene was continuously added over 1 hour. After the addition of styrene was completed, a polymerization reaction was carried out for another 1 hour to obtain a solution containing a styrene-isoprene-styrene triblock copolymer having active ends (the third stage of polymerization). The polymerization conversion rate of styrene at this time was 100%.

[0124] Next, as a polymerization terminator, 195 mmol of methanol was added and mixed to deactivate a part 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 B' which is for obtaining a hydrogenated block copolymer B.

[0125] Thereafter, while continuously controlling the temperature to maintain 50 to 60 °C, 1.06 kg of styrene was continuously added over 1 hour. After the addition of styrene was completed, the polymerization reaction was carried out for another 1 hour to obtain a solution containing a styrene-isoprene-styrene triblock copolymer having an active end, which was the block copolymer A' for obtaining the hydrogenated block copolymer A (the fourth stage of polymerization). The polymerization conversion rate of styrene at this time was 100%.

[0126] Finally, as a polymerization terminator, 345 mmol of methanol was added and mixed to deactivate all the active ends of the styrene-isoprene-styrene triblock copolymer having an active end, thereby completing the polymerization reaction, and thus a solution containing a block copolymer composition before hydrogenation was obtained. The amounts of each reagent used in the reaction are summarized in Table 1.

[0127] (2) Hydrogenation reaction of the block copolymer composition before hydrogenation A solution containing a hydrogenated block copolymer composition was obtained by performing a hydrogenation reaction on the solution containing the block copolymer composition before hydrogenation obtained above. The hydrogenation reaction was carried out by adding a Ni(AcAc)2-TIBAL catalyst as a hydrogenation catalyst to the solution containing the block copolymer composition before hydrogenation obtained above at a ratio of 0.5% by weight based on the block copolymer composition before hydrogenation, under the conditions of a hydrogen pressure of 3 MPa, a reaction temperature of 80 °C, and a reaction time of 3 hours.

[0128] A part of the solution containing the hydrogenated block copolymer composition thus obtained was taken out, and the weight average molecular weight of each block copolymer contained in the composition, the weight ratio of each block copolymer in the composition, the weight average molecular weight of the styrene polymer block of each block copolymer, the weight average molecular weight of the isoprene polymer block of each block copolymer, the styrene unit content of each block copolymer, the styrene unit content of the block copolymer composition (as a whole), the vinyl bond content of the isoprene polymer block of each block copolymer, and the olefin hydrogenation rate were determined. These values are summarized in Table 2.

[0129] (3) Recovery and Molding of Hydrogenated Block Copolymer Composition To 100 parts of the solution containing the hydrogenated block copolymer composition obtained as described above, 0.3 part of 2,6-di-t-butyl-p-cresol was added as an antioxidant and mixed. The mixed solution was dropped little by little into warm water heated to 85 - 95 °C to volatilize the solvent and obtain a precipitate. The obtained precipitate was pulverized and dried with hot air at 85 °C to recover a clam-shaped hydrogenated block copolymer composition.

[0130] Next, the obtained clam-shaped hydrogenated block copolymer composition was supplied to a single-screw extruder equipped with an underwater hot cut device at the tip of the extruder to form cylindrical pellets with an average diameter of 5 mm and an average length of about 5 mm. This pellet-shaped hydrogenated block copolymer composition was put into a hopper dryer heated to 60 °C and dried for 10 hours while circulating dry air at 60 °C.

[0131] Next, the dried pellet-shaped hydrogenated block copolymer composition obtained as described above was heated and melted at 200 °C using a twin-screw extruder equipped with a T-die and extruded to form a film with a thickness of 0.2 mm. Tensile modulus, permanent elongation, and thermal stability of this film were measured. These results are summarized in Table 2. The details of the film forming conditions are as follows. Composition processing speed: 15 kg / hr Film take-up speed: 10 m / min Extruder temperature: Inlet 200 °C, T-die 220 °C Screw: Full flight Extruder L / D: 42 T-die: Width 300 mm, lip 1 mm

[0132] 〔Example 2〕 A hydrogenated block copolymer composition was produced in the same manner as in Example 1 except that the reaction time in the hydrogenation reaction was changed from 3 hours to 1 hour. Using the obtained hydrogenated block copolymer composition, pellets and a film were obtained and measured in the same manner. The results are summarized in Table 2.

[0133] 〔Example 3〕 The amounts of styrene, dibutyl ether, n-butyllithium, isoprene, and methanol were changed as shown in Table 1, respectively, and the hydrogenation reaction time was changed from 3 hours to 15 minutes. Otherwise, in the same manner as in Example 1, a hydrogenated block copolymer composition was produced. Using the obtained hydrogenated block copolymer composition, pellets and films were obtained, and the same measurements were carried out. The results are summarized in Table 2.

[0134] 〔Example 4〕 The amounts of styrene, dibutyl ether, n-butyllithium, isoprene, and methanol were changed as shown in Table 1, respectively, and the hydrogenation reaction time was changed from 3 hours to 2 hours. Otherwise, in the same manner as in Example 1, a hydrogenated block copolymer composition was produced. Using the obtained hydrogenated block copolymer composition, pellets and films were obtained, and the same measurements were carried out. The results are summarized in Table 2.

[0135] 〔Example 5〕 (1) Production of block copolymer composition before hydrogenation 56.6 kg of cyclohexane, 523 mmol of dibutyl ether, and 0.69 kg of styrene were added to a pressure reactor. While stirring the total volume at 40 °C, 280.2 mmol of n-butyllithium (1.6 M solution) was added. After the addition was completed, the temperature was raised to 50 °C and a polymerization reaction was carried out for 1 hour (the first stage of polymerization). The polymerization conversion rate of styrene at this time was 100% by weight.

[0136] Subsequently, while controlling the temperature to maintain 50 - 60 °C, 7.99 kg of isoprene was continuously added to the reactor over 1 hour. After the addition of isoprene was completed, a polymerization reaction was carried out for another 1 hour (the second stage of polymerization). The polymerization conversion rate of isoprene at this time was 100%.

[0137] Next, 101 mmol of dimethyldichlorosilane was added as a bifunctional coupling agent and mixed to couple a part of the styrene-isoprene-styrene triblock copolymer having active ends, thereby obtaining a solution containing a styrene-isoprene-styrene triblock copolymer that becomes block copolymer B' for obtaining hydrogenated block copolymer B.

[0138] Thereafter, while continuously controlling the temperature to maintain 50 - 60 °C, 0.61 kg of styrene was continuously added over 1 hour. After the addition of styrene was completed, the polymerization reaction was further carried out for 1 hour to obtain a solution containing a styrene-isoprene-styrene triblock copolymer having active ends, which becomes block copolymer A' for obtaining hydrogenated block copolymer A (the third stage of polymerization). At this time, the polymerization conversion rate of styrene was 100%.

[0139] Finally, 358 mmol of methanol was added as a polymerization terminator and mixed to deactivate all the active ends of the styrene-isoprene-styrene triblock copolymer having active ends, thereby completing the polymerization reaction, and thus a solution containing the block copolymer composition before hydrogenation was obtained. The amounts of each reagent used in the reaction are summarized in Table 1.

[0140] (2) Hydrogenation reaction of the block copolymer composition before hydrogenation A hydrogenation reaction was carried out on the solution containing the block copolymer composition before hydrogenation obtained above to obtain a solution containing a hydrogenated block copolymer composition. The hydrogenation reaction was carried out under the same conditions as in Example 1. Then, a part of the obtained solution containing the hydrogenated block copolymer composition was taken out and each measurement was carried out in the same manner as in Example 1. The results are summarized in Table 2.

[0141] (3) Recovery and molding of the hydrogenated block copolymer composition Using the solution containing the obtained hydrogenated block copolymer composition, recovery was carried out in the same manner as in Example 1, and then pellets and films were obtained and the same measurements were carried out. The results are summarized in Table 2.

[0142] [Example 6] A hydrogenated block copolymer composition was produced in the same manner as in Example 1, except that 270.6 mmol of ethylene glycol dibutyl ether was used instead of dibutyl ether. Using the obtained hydrogenated block copolymer composition, pellets and films were obtained, and the same measurements were carried out. The results are summarized in Table 2.

[0143] [Example 7] A hydrogenated block copolymer composition was produced in the same manner as in Example 6, except that the amount of ethylene glycol dibutyl ether was changed to 1353 mmol. Using the obtained hydrogenated block copolymer composition, pellets and films were obtained, and the same measurements were carried out. The results are summarized in Table 2.

[0144] [Example 8] A hydrogenated block copolymer composition was produced in the same manner as in Example 6, except that the amount of ethylene glycol dibutyl ether was changed to 2706 mmol. Using the obtained hydrogenated block copolymer composition, pellets and films were obtained, and the same measurements were carried out. The results are summarized in Table 2.

[0145] [Example 9] A hydrogenated block copolymer composition was produced in the same manner as in Example 6, except that the amount of ethylene glycol dibutyl ether was changed to 4059 mmol. Using the obtained hydrogenated block copolymer composition, pellets and films were obtained, and the same measurements were carried out. The results are summarized in Table 2.

[0146] [Comparative Example 1] (1) Production of the block copolymer composition before hydrogenation 56.6 kg of cyclohexane, 517 mmol of dibutyl ether, and 1.5 kg of styrene were added to a pressure reactor. While stirring the entire volume at 40°C, 277.5 mmol of n-butyllithium (1.6 M solution) was added. After the addition was completed, the temperature was raised to 50°C and a polymerization reaction was carried out for 1 hour (the first stage of polymerization). The polymerization conversion rate of styrene at this time was 100% by weight.

[0147] Subsequently, while controlling the temperature to maintain 50 - 60°C, 6.99 kg of isoprene was continuously added to the reactor over 1 hour. After the addition of isoprene was completed, a polymerization reaction was carried out for another 1 hour (the second stage of polymerization). The polymerization conversion rate of isoprene at this time was 100%.

[0148] Next, while controlling the temperature to maintain 50 - 60°C, 1.5 kg of styrene was continuously added to the reactor over 1 hour. After the addition of styrene was completed, a polymerization reaction was carried out for another 1 hour to obtain a solution containing a styrene-isoprene-styrene triblock copolymer having active ends (the third stage of polymerization). The polymerization conversion rate of styrene at this time was 100%.

[0149] Finally, 555 mmol of methanol was added as a polymerization terminator and mixed to deactivate all the active ends of the styrene-isoprene-styrene triblock copolymer having active ends, thereby completing the polymerization reaction, and thus a solution containing a block copolymer composition before hydrogenation was obtained. The amounts of each reagent used in the reaction are summarized in Table 1.

[0150] (2) Hydrogenation reaction of the block copolymer composition before hydrogenation A solution containing the block copolymer composition before hydrogenation obtained above was subjected to a hydrogenation reaction to obtain a solution containing a hydrogenated block copolymer composition. The hydrogenation reaction was carried out under the same conditions as in Example 1. Then, a part of the solution containing the obtained hydrogenated block copolymer composition was taken out and each measurement was carried out in the same manner as in Example 1. The results are summarized in Table 2.

[0151] (3) Recovery and Molding of Hydrogenated Block Copolymer Composition Using the solution containing the obtained hydrogenated block copolymer composition, recovery was carried out in the same manner as in Example 1. After that, pellets and films were obtained and the same measurements were performed. The results are summarized in Table 2.

[0152] [Comparative Example 2] A hydrogenated block copolymer composition was produced in the same manner as in Comparative Example 1, except that the reaction time in the hydrogenation reaction was changed from 3 hours to 20 minutes. Using the obtained hydrogenated block copolymer composition, pellets and films were obtained and the same measurements were performed. The results are summarized in Table 2.

[0153] [Comparative Examples 3 and 4] An unhydrogenated block copolymer composition was produced in the same manner as in Example 1, except that the amounts of styrene, dibutyl ether, n-butyllithium, isoprene, and methanol were changed as shown in Table 1 respectively, and the hydrogenation reaction was not carried out. Using the obtained unhydrogenated block copolymer composition, pellets and films were obtained and the same measurements were performed. The results are summarized in Table 2.

[0154] [Comparative Example 5] An unhydrogenated block copolymer composition was produced in the same manner as in Comparative Example 1, except that the amounts of styrene, dibutyl ether, n-butyllithium, isoprene, and methanol were changed as shown in Table 1 respectively, and the hydrogenation reaction was not carried out. Using the obtained unhydrogenated block copolymer composition, pellets and films were obtained and the same measurements were performed. The results are summarized in Table 2.

[0155] [Table 1]

[0156] [Table 2]

[0157] As shown in Table 1, according to the hydrogenated block copolymer composition containing the hydrogenated block copolymer A represented by the general formula (A) and the hydrogenated block copolymer B represented by the general formula (B) at a ratio of A / B (weight ratio) = 10 / 90 to 80 / 20, and having a hydrogenation rate of olefin in the polymer components constituting the hydrogenated block copolymer composition of 10 to 100%, the 50% tensile modulus was high, the permanent elongation was small, and moreover, the viscosity retention rate after heating at 170°C for 1 hour was high and the thermal stability was also excellent (Examples 1 to 9). On the other hand, when the hydrogenated block copolymer A represented by the general formula (A) was not contained, although the thermal stability was excellent, the permanent elongation increased as a result (Comparative Examples 1 and 2). Also, when the hydrogenation rate of olefin was less than 10%, the viscosity retention rate after heating at 170°C for 1 hour was low and the thermal stability was poor as a result (Comparative Examples 3 and 4). Furthermore, when the hydrogenated block copolymer A represented by the general formula (A) was not contained and the hydrogenation rate of olefin was less than 10%, the permanent elongation was large, and moreover, the viscosity retention rate after heating at 170°C for 1 hour was low and the thermal stability was also poor (Comparative Example 5).

Claims

1. 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), wherein the weight ratio (A / B) of the hydrogenated block copolymer A to the hydrogenated block copolymer B is 10 / 90 to 45 / 55, and the hydrogenation rate of the olefin in the polymer component constituting the hydrogenated block copolymer composition is 10 to 100%. A hydrogenated block copolymer composition. Ar1 ａ -HD ａ -Ar2 ａ (A) Ar1 ｂ -HD ｂ -Ar2 ｂ (B) (In the above general formula (A) and general formula (B), Ar1 ａ , Ar2 ａ , Ar1 ｂ , and Ar2 ｂ are aromatic vinyl polymer blocks, HD ａ and HD ｂ are hydrogenated polymer blocks of conjugated diene polymers, and the ratio of the weight average molecular weight (Mw(Ar1 ａ )) of Ar1 ａ to the weight average molecular weight (Mw(Ar2 ａ )) of Ar2 ａ (Mw(Ar2 ａ ) / Mw(Ar1 ａ )) is 2.6 to 66, and the ratio of the weight average molecular weight (Mw(Ar2 ｂ )) of Ar2 ｂ to the weight average molecular weight (Mw(Ar1 ｂ )) of Ar1 ｂ (Mw(Ar2 ｂ ) / Mw(Ar1 ｂ )) is 0.95 to 1.

05. In the above general formula (A) and general formula (B), the weight average molecular weights of Ar1 ａ , Ar1 ｂ , and Ar2 ｂ are each in the range of 2,000 to 40,000, and the weight average molecular weights of HD ａ and HD ｂ are each in the range of 15,000 to 300,000.)

2. In the above general formula (A) and general formula (B), HD ａ and HD ｂ The hydrogenated block copolymer composition according to claim 1, wherein is a hydrogenated polymer block of a conjugated diene polymer having a vinyl bond content of 1 to 80 mol%.

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

4. A method for producing the hydrogenated block copolymer composition according to any one of claims 1 to 3, the method for producing a hydrogenated block copolymer composition having the following steps (1) to (7). (1): A step of obtaining a solution containing an aromatic vinyl polymer having an active end by polymerizing an aromatic vinyl monomer using a polymerization initiator in a solvent (2): A conjugated diene monomer is added to the solution containing the aromatic vinyl polymer having an active end obtained in the step (1), and the conjugated diene monomer is polymerized to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having an active end. step (3): An aromatic vinyl monomer is added to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in the step (2), and the aromatic vinyl monomer is polymerized to obtain an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end. step of obtaining a solution containing (4): A polymerization terminator is added to the solution containing the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end obtained in the step (3) in an amount less than 1 molar equivalent to the active end, and a part of the active end of the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having an active end is deactivated to obtain a solution containing a block copolymer B'. step (5): An aromatic vinyl monomer is added to the solution containing the block copolymer B' obtained in the step (4), and the aromatic vinyl monomer is polymerized to obtain a solution containing the block copolymer B' and the block copolymer A'. step Step (6): A step of obtaining a solution containing a hydrogenated block copolymer B and a hydrogenated block copolymer A by subjecting a solution containing the block copolymer B' and the block copolymer A' obtained in the step (5) to a hydrogenation reaction. Step (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).

5. A method for producing a hydrogenated block copolymer composition according to any one of Claims 1 to 3, the method for producing a hydrogenated block copolymer composition having the following steps (1a) to (6a). Step (1a): A step of obtaining a solution containing an aromatic vinyl polymer having an active end by polymerizing an aromatic vinyl monomer using a polymerization initiator in a solvent. Step (2a): A step of adding a conjugated diene monomer to the solution containing the aromatic vinyl polymer having an active end obtained in the step (1a) and polymerizing the conjugated diene monomer to obtain a solution containing an aromatic vinyl-conjugated diene block copolymer having an active end. Step (3a): Adding a bifunctional coupling agent to the solution containing the aromatic vinyl-conjugated diene block copolymer having an active end obtained in the step (2a) in an amount such that the total amount of functional groups is less than 1 molar equivalent with respect to the active end, and coupling a part of the aromatic vinyl-conjugated diene block copolymer having an active end to obtain a solution containing a block copolymer B'. Step (4a): A step of adding an aromatic vinyl monomer to the solution containing the block copolymer B' obtained in the step (3a) and polymerizing the aromatic vinyl monomer to obtain a solution containing the block copolymer B' and the block copolymer A'. Step (5a): A step of obtaining a solution containing a hydrogenated block copolymer B and a hydrogenated block copolymer A by subjecting the solution containing the block copolymer B' and the block copolymer A' obtained in the step (4a) to a hydrogenation reaction. Step (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).

6. A film formed by molding the hydrogenated block copolymer composition according to any one of Claims 1 to 3.

7. The hydrogenated block copolymer composition according to any one of Claims 1 to 3, A hydrogenated block copolymer composition in which the weight ratio (A / B) of the hydrogenated block copolymer A to the hydrogenated block copolymer B is 10 / 90 to 30 / 70.

Images