JP2002161186A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new thermoplastic elastomer composition excellent in softness, molding workability, rubber property, mechanical strength, gas barrier property, sealability and compression set property. SOLUTION: The thermoplastic elastomer composition contains (A) an isobutylene block copolymer with (a) a polymer block mainly consisting of isobutylene and (b) a polymer block mainly consisting of an aromatic vinyl compound, and (B) a crosslinked isobutylene-free block copolymer with (c) a polymer block mainly consisting of a conjugated diene compound and the above (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel thermoplastic elastomer composition having excellent flexibility, excellent moldability, rubbery properties, mechanical strength, gas barrier properties and sealing properties, and excellent compression set properties. It is about things.

[0002]

2. Description of the Related Art Conventionally, as a polymer material having elasticity, a material obtained by blending a crosslinking agent or a reinforcing agent with rubbers such as natural rubber or synthetic rubber and crosslinking under high temperature and high pressure has been widely used. However, such rubbers require a process of performing crosslinking and molding under a high temperature and a high pressure for a long time, and are inferior in workability. In addition, since the crosslinked rubber does not show thermoplasticity, recycling molding is generally impossible like thermoplastic resins. Therefore, in recent years, various types of thermoplastic elastomers have been developed that can easily produce molded articles by using general-purpose melt molding techniques such as hot press molding, injection molding, and extrusion molding, like ordinary thermoplastic resins. ing. Such thermoplastic elastomers include:
At present, various types of polymers such as olefins, urethanes, esters, styrenes, and vinyl chlorides have been developed and are commercially available.

[0003] Of these, styrene-based thermoplastic elastomers are rich in flexibility and excellent in rubber elasticity at room temperature. As a styrene-based thermoplastic elastomer,
Styrene-butadiene-styrene block copolymer (S
BS), styrene-isoprene-styrene block copolymer (SIS), and hydrogenated styrene-
Ethylene butylene-styrene block copolymer (SEB
S) and styrene-ethylene propylene-styrene block copolymer (SEPS) have been developed. However, since these block copolymers do not have sufficient gas barrier properties, sealing properties, and stickiness of the material itself,
It cannot be used effectively as a sealing material such as a packing material, a sealing material, a gasket, or a plug.

On the other hand, thermoplastic elastomers having high flexibility, good rubber elasticity at room temperature, and excellent gas barrier properties and sealing properties include a polymer block mainly composed of isobutylene and an aromatic vinyl compound. An isobutylene-based block copolymer containing a polymer block mainly composed of However, this isobutylene-based block copolymer has a problem in the pressure deformation rate (compression set) during heating and rubber elasticity at high temperatures.

[0005] A thermoplastic polymer composition comprising a crosslinked product of an isobutylene-based block copolymer containing a polymer block mainly composed of isobutylene and a rubber is also known (Republished Patent WO98 / 14518). Although this composition is excellent in gas barrier properties, sealing properties and compression set properties, it has a problem that its hardness and strength are low because rubber is used as a crosslinked product.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a high flexibility, moldability,
An object of the present invention is to provide a thermoplastic elastomer composition having excellent rubber properties, mechanical strength, gas barrier properties and sealing properties, and particularly excellent compression set properties.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that gas barrier properties and
A conjugated diene-based block copolymer (A) containing a polymer block (a) mainly composed of isobutylene having excellent sealing properties and a polymer block (b) mainly composed of an aromatic vinyl compound; A block copolymer containing a polymer block (c) mainly composed of a compound and a polymer block (b) mainly composed of an aromatic vinyl compound, and / or a hydrogenated block obtained by hydrogenating the same. By melting and mixing a crosslinked product (B) of at least one non-isobutylene-based block copolymer selected from polymers, it is rich in flexibility, moldability, rubber-like properties, mechanical strength, gas barrier properties and the like. A novel thermoplastic elastomer composition having excellent sealing properties and excellent compression set characteristics has been obtained. That is, the present invention provides an isobutylene-based block copolymer (A) containing a polymer block (a) mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound, and a conjugated diene-based compound. A thermoplastic elastomer composition containing a crosslinked product (B) of a non-isobutylene-based block copolymer containing the polymer block (c) containing the above (B) and (B),
Contains a polymer block (c) mainly composed of a conjugated diene-based compound and a polymer block (b) mainly composed of an aromatic vinyl-based compound, and is a hydrogenated non-isobutylene-based block copolymer obtained by hydrogenation. (B) contains a polymer block (c) mainly composed of a conjugated diene compound and a polymer block (b) mainly composed of an aromatic vinyl compound, It can also be a crosslinked product of a mixture of a hydrogenated non-isobutylene-based block copolymer obtained by hydrogenation and a non-isobutylene-based block copolymer not hydrogenated.

[0008] The crosslinked product (B) of the non-isobutylene-based block copolymer may be crosslinked before being mixed with the isobutylene-based block copolymer (A), or may be mixed with the isobutylene-based block copolymer (A). It is preferable that the non-isobutylene block copolymer is dynamically crosslinked at the time of melt-kneading the non-isobutylene block copolymer.

It is preferable that the copolymer further contains a plasticizer. The isobutylene-based block copolymer (A) comprises at least one of a polymer block (a) containing isobutylene as a main component and an aromatic vinyl compound as a main component. More preferably, it is a block copolymer comprising at least two of the polymer blocks (b).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic elastomer composition of the present invention comprises an isobutylene-based polymer block (a) containing a polymer block mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound. A block copolymer (A); a block copolymer containing a polymer block (c) mainly composed of a conjugated diene compound and a polymer block (b) mainly composed of an aromatic vinyl compound, and / or
Or a crosslinked product (B) of at least one non-isobutylene-based block copolymer selected from hydrogenated block copolymers obtained by hydrogenation thereof, and an isobutylene-based block copolymer ( A) The non-isobutylene block copolymer is dynamically cross-linked at the time of melt-kneading the non-isobutylene block copolymer, or the cross-linked product of the non-isobutylene block copolymer (B) is an isobutylene block copolymer. It is pre-crosslinked before being mixed with the block copolymer (A). It is rich in flexibility, excellent in moldability, rubbery properties, mechanical strength, gas barrier properties and sealing properties. It has excellent permanent set characteristics.

In the isobutylene block copolymer (A) of the present invention, the polymer block (a) mainly composed of isobutylene means that the isobutylene content is 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight. The block that occupies the above. The monomer other than isobutylene in the polymer block mainly composed of isobutylene is not particularly limited as long as it is a cationically polymerizable monomer component.Aromatic vinyls, aliphatic olefins, dienes,
Examples thereof include monomers such as vinyl ethers and β-pinene. These may be used alone or in combination of two or more.

The polymer block (b) mainly composed of an aromatic vinyl compound of the isobutylene block copolymer (A) is defined as a polymer block containing at least 50% by weight of an aromatic vinyl compound.
Preferably 70% by weight or more, more preferably 90% by weight
The block that occupies the above. The monomer other than the aromatic vinyl compound in the polymer block mainly composed of an aromatic vinyl compound is not particularly limited as long as it is a monomer that can be cationically polymerized, but may be an aliphatic olefin, a diene, or a vinyl ether. And monomers such as β-pinene.

The aromatic vinyl compound of the polymer block (b) includes styrene, α-methylstyrene, β-methylstyrene, p-methylstyrene, t-butylstyrene, monochlorostyrene, dichlorostyrene, methoxystyrene, indene And the like. Among the above compounds, styrene, α from the balance of cost, physical properties and productivity
-Methylstyrene, p-methylstyrene, and indene are preferred, and two or more of them may be selected.

The ratio of the polymer block (a) mainly composed of isobutylene and the polymer block (b) mainly composed of an aromatic vinyl compound in the isobutylene-based block copolymer (A) is not particularly limited. From the balance between physical properties and processability, the polymer block (a) mainly composed of isobutylene is 95 to 20 parts by weight, and the polymer block (b) mainly composed of an aromatic vinyl compound is 5 to 80 parts by weight. It is particularly preferable that the polymer block (a) mainly composed of isobutylene is 90 to 60 parts by weight, and the polymer block (b) mainly composed of an aromatic vinyl compound is 10 to 40 parts by weight.

The preferred structure of the isobutylene-based block copolymer (A) of the present invention is at least one of the polymer blocks (a) mainly composed of isobutylene, in view of the physical properties and processability of the resulting composition. And at least two polymer blocks (b) mainly composed of an aromatic vinyl compound. The structure is not particularly limited. For example, a triblock copolymer formed from (b)-(a)-(b), ｛(b)-
At least one selected from (a) a multi-block copolymer having repeating 繰 り 返 し units, and a star-shaped polymer having a di-block copolymer (b)-(a) as an arm can be used. . Further, in the isobutylene-based block copolymer (A), in addition to the above structure, a polymer mainly composed of isobutylene, a polymer mainly composed of an aromatic vinyl compound, and a dimer composed of (a)-(b) At least one of block copolymers may be included. However, from the viewpoint of physical properties and processability, at least one of the isobutylene-based polymer block (a) contained in the isobutylene-based block copolymer (A) and the polymer mainly containing an aromatic vinyl-based compound The structure comprising at least two blocks (b) must not be less than 50% by weight.

The number-average molecular weight of the isobutylene-based block copolymer (A) is not particularly limited.
00000 is preferred, and 40,000 to 400,000 is particularly preferred. When the number average molecular weight is less than 30,000, mechanical properties and the like are not sufficiently exhibited, and
If the ratio exceeds, the moldability and the like are greatly reduced.

The composition of the present invention comprises the above-mentioned isobutylene-based block copolymer (A), a polymer block (c) mainly composed of a conjugated diene-based compound, and a polymer block mainly composed of an aromatic vinyl-based compound (C). a cross-linked product (B) of at least one non-isobutylene-based block copolymer selected from a block copolymer containing b) and / or a hydrogenated block copolymer obtained by hydrogenating the same. It is.

The polymer block (c) mainly containing a conjugated diene compound is a block in which the conjugated diene compound accounts for 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more. Say. The conjugated diene compound is not particularly limited, for example, butadiene,
At least one selected from the group consisting of isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like is used, and among them, butadiene and isoprene are preferable.

The polymer (c) mainly composed of a conjugated diene compound and the polymer mainly composed of an aromatic vinyl compound used in the crosslinked product (B) of the non-isobutylene-based block copolymer of the present invention. The ratio of the polymer block (c) to the polymer block (b) in the block copolymer containing the block (b) is not particularly limited. However, from the balance between physical properties and processability, the polymer block ( c) is 95-
20 parts by weight, preferably 5 to 80 parts by weight of the polymer block (b), and 90 to 5 parts by weight of the polymer block (c).
It is particularly preferable that the amount of the polymer block (b) is 10 to 50 parts by weight, and 0 part by weight. The structure of the block copolymer containing a polymer block (c) mainly composed of a conjugated diene-based compound and a polymer block (b) mainly composed of an aromatic vinyl-based compound is not particularly limited. (C)
-A diblock copolymer formed from (b), (b)-
(C) a triblock copolymer formed from (b),
At least one selected from a multiblock body and a star-shaped polymer having a diblock copolymer (b)-(c) as an arm can be used.

The block copolymer containing such a polymer block (c) mainly composed of a conjugated diene compound and a polymer block (b) mainly composed of an aromatic vinyl compound is not particularly limited. Is, for example, a styrene-based thermoplastic elastomer made of Nippon Synthetic Rubber Co., Ltd. comprising a styrene-butadiene-block copolymer (trade name “JS
R-TR ”).

The crosslinked product (B) of the non-isobutylene-based block copolymer includes a polymer block (c) mainly composed of a conjugated diene compound and a polymer block (b) mainly composed of an aromatic vinyl compound. A hydrogenated block copolymer obtained by hydrogenating the above block copolymer can also be used. That is, the hydrogenated block copolymer is composed of a polymer block mainly composed of a hydrogenated conjugated diene-based compound and a polymer block mainly composed of an aromatic vinyl-based compound. Examples include a styrene / ethylene butylene-block copolymer obtained by hydrogenating a block copolymer, and a styrene / ethylene propylene-block copolymer obtained by hydrogenating a styrene / isoprene-block copolymer.

The compounding amount of the crosslinked product (B) of the non-isobutylene-based block copolymer is preferably 10 to 220 parts by weight, preferably 20 to 200 parts by weight, per 100 parts by weight of the isobutylene-based block copolymer (A). Is more preferable. Crosslinked product of non-isobutylene-based block copolymer (B)
If the amount is less than 10 parts by weight, the compression set characteristics will not be improved, and if it exceeds 220 parts by weight, there will be a problem in moldability.

The crosslinked product (B) of the non-isobutylene-based block copolymer of the present invention is a product which is dynamically crosslinked during melt-kneading of the isobutylene-based block copolymer (A) and the non-isobutylene-based block copolymer. Alternatively, the cross-linked product (B) of the non-isobutylene-based block copolymer may be cross-linked before being mixed with the isobutylene-based block copolymer (A). As means for crosslinking the non-isobutylene-based block copolymer, a known method can be used, and there is no particular limitation. For example, thermal crosslinking by heating,
Crosslinking with a crosslinking agent can be performed.

As the crosslinking agent for obtaining the crosslinked product (B) of the non-isobutylene-based block copolymer of the present invention, it is preferable to use an organic peroxide. Examples of the organic peroxide include dicumyl peroxide, di-t
tert-butyl peroxide, 2,5-dimethyl-
2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (te
rt-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide,
2,4-dichlorobenzoyl peroxide, tert
-Butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butylcumyl peroxide and the like.

Of these, 2,5-dimethyl 2,5-di- (ter) is preferable in terms of odor, coloring, and scorch stability.
Most preferred are t-butylperoxy) hexane and 2,5-dimethyl2,5-di- (tert-butylperoxy) hexyne-3.

The amount of the organic peroxide is preferably in the range of 0.5 to 3.5 parts by weight based on 100 parts by weight of the non-isobutylene-based block copolymer at the time of adding the organic peroxide.

In the method for producing the composition of the present invention, a polyfunctional vinyl monomer such as divinylbenzene or triallyl cyanurate, or ethylene glycol dimethacrylate,
Polyfunctional methacrylate monomers such as diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate can be blended as a crosslinking aid. With such a compound, a uniform and efficient crosslinking reaction can be expected.

Among them, particularly, ethylene glycol dimethacrylate and triethylene glycol dimethacrylate are easy to handle and have a peroxide solubilizing action,
Since it acts as a peroxide dispersing agent, the crosslinking effect by heat treatment is uniform and effective, and a crosslinked thermoplastic elastomer having a good balance between hardness and rubber elasticity is obtained, which is preferable.

The amount of addition of the crosslinking aid is preferably in the range of 0.9 to 8.0 parts by weight based on 100 parts by weight of the non-isobutylene-based block copolymer at the time of addition.

The composition of the present invention further comprises, in addition to the cross-linked product (B) of the isobutylene-based block copolymer (A) and the non-isobutylene-based block copolymer, a moldability and flexibility. It is preferred to add a plasticizer. As the plasticizer, mineral oil used for processing rubber, or a liquid or low molecular weight synthetic softener can be used. As mineral oils, paraffinic, naphthenic,
And aromatic high-boiling petroleum components, but paraffinic and naphthenic based which do not inhibit the crosslinking reaction are preferred. The liquid or low molecular weight synthetic softener is not particularly limited, and examples thereof include polybutene, hydrogenated polybutene, liquid polybutadiene, hydrogenated liquid polybutadiene, and polyalphaolefins. One or more of these plasticizers can be used. The amount of the plasticizer is 10 to 20 parts by weight based on 100 parts by weight of the isobutylene-based block copolymer (A).
It is preferably 0 parts by weight. If the amount is more than 200 parts by weight, problems arise in mechanical strength and moldability.

The composition of the present invention further comprises a reinforcing agent, a filler, a hindered phenol-based or hindered amine-based antioxidant, an ultraviolet absorber, A light stabilizer, a pigment, a surfactant and the like can be appropriately compounded.

The most preferred composition of the thermoplastic elastomer composition of the present invention is a crosslinked product of a non-isobutylene block copolymer (B) of 20 to 200 parts by weight per 100 parts by weight of an isobutylene block copolymer (A). Parts by weight, 10 to 200 parts by weight of a plasticizer. Further, in this case, based on 100 parts by weight of the isobutylene-based block copolymer (A),
The crosslinking agent is 0.1 to 7 parts by weight, and the crosslinking aid is 0.45 to 16
Parts by weight.

The method for producing the thermoplastic elastomer composition of the present invention is not particularly limited, and the isobutylene-based block copolymer (A), the crosslinked product of the non-isobutylene-based block copolymer (B), and optionally used. Any method can be employed as long as the above-mentioned components can be uniformly mixed.

When the isobutylene-based block copolymer (A) and the non-isobutylene-based block copolymer are melt-mixed, the non-isobutylene-based block copolymer is dynamically crosslinked to form a crosslinked product of the non-isobutylene-based block copolymer ( When the thermoplastic elastomer composition of the present invention is produced by B), it can be preferably carried out by the following exemplified methods.

For example, in the case of using a closed kneading apparatus or a batch kneading apparatus such as Labo Plastomill, Brabender, Banbury mixer, kneader, roll, etc., all the components other than the crosslinking agent and the crosslinking aid are used. May be mixed in advance and melt-kneaded until uniform, and then a crosslinking agent and a crosslinking aid may be added to the mixture to stop the melt-kneading sufficiently in the crosslinking reaction.

When a continuous melt kneading apparatus such as a single screw extruder or a twin screw extruder is used, all components other than the crosslinking agent and the crosslinking auxiliary are melted in advance by an extruder or the like. The mixture is melt-kneaded by a kneading device, pelletized, and then the pellet is dry-blended with a crosslinking agent and a crosslinking aid.Then, the mixture is melt-kneaded with a melt-kneading device such as an extruder to form a non-isobutylene-based block copolymer. Dynamically crosslinked, isobutylene-based block copolymer (A) of the present invention,
A method for producing a thermoplastic elastomer composition comprising a crosslinked product (B) of a non-isobutylene-based block copolymer. Alternatively, all components other than the cross-linking agent and the cross-linking aid are melt-kneaded by a melt-kneading device such as an extruder, and the cross-linking agent and the cross-linking auxiliary are added from the middle of the extruder cylinder and further melt-kneaded, The non-isobutylene-based block copolymer is dynamically crosslinked to produce a thermoplastic elastomer composition comprising the isobutylene-based block copolymer (A) of the present invention and a crosslinked product of the non-isobutylene-based block copolymer (B). A method or the like can be adopted.

In performing the above-mentioned method of performing dynamic crosslinking simultaneously with melt kneading, a temperature of 150 to 210 ° C. is preferable. In this case, the isobutylene-based block copolymer (A) does not cause a crosslinking reaction, and only the non-isobutylene-based block copolymer can be crosslinked.

A crosslinked product (B) of a non-isobutylene block copolymer is prepared in advance, and the crosslinked product (B) is mixed with the isobutylene block copolymer (A) to prepare the thermoplastic elastomer composition of the present invention. In the case of adjusting an object, a method exemplified below is preferably adopted.

For example, a crosslinking agent and a crosslinking aid are added to the above-mentioned non-isobutylene-based block copolymer, and the mixture is sufficiently kneaded at an appropriate temperature using a kneader or the like usually used for producing a rubber cross-linked product. The resulting kneaded product is subjected to a crosslinking reaction using a press machine or the like at an appropriate crosslinking temperature and crosslinking time, and then cooled and pulverized to obtain a crosslinked product (B) of a non-isobutylene-based block copolymer. Then, the thermoplastic elastomer composition of the present invention can be produced by melt-mixing the crosslinked product (B) with the isobutylene-based block copolymer (A).

At this time, the method of melt-mixing the crosslinked product (B) of the non-isobutylene-based block copolymer and the isobutylene-based block copolymer (A) is a conventional method for producing a thermoplastic resin or a thermoplastic elastomer composition. Any of the known methods used can be employed, for example, Labo Plastomill, Banbury mixer, single-screw extruder, twin-screw extruder, can be performed using other melt-kneading equipment, and melt-kneading temperature Is preferably 150 to 210 ° C.

The thermoplastic elastomer composition of the present invention comprises:
The thermoplastic resin composition can be molded using a molding method and a molding apparatus generally adopted, and for example, can be melt-molded by extrusion molding, injection molding, press molding, blow molding, or the like. Further, the thermoplastic elastomer composition of the present invention is excellent in moldability, gas barrier properties, and compression set characteristics, and thus can be effectively used as a sealing material such as a packing material, a sealing material, a gasket, and a plug. it can.

[0042]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Prior to the examples, various measuring methods, evaluation methods,
An example will be described.

(Hardness) According to JIS K 6352, a test piece used was a 12.0 mm press sheet.

(Tensile rupture strength) According to JIS K6251, the test piece was a 2 mm thick pressed sheet, and 3 dumbbells were used.
It was used by punching it into a model. The tensile speed was 500 mm / min.

(Tensile elongation at break) In accordance with JIS K6251, the test piece was a 2 mm-thick pressed sheet, and 3 dumbbells were used.
It was used by punching it into a model. The tensile speed was 500 mm / min.

(Permanent Compression Set) According to JIS K 6262, a 12.0 mm-thick pressed sheet was used as a test piece. It was measured under the conditions of 100 ° C. × 22 hours and 25% deformation. Abbreviations and specific contents of the materials used in Examples and Comparative Examples are as follows. SIBS: polystyrene-polyisobutylene-polystyrene triblock copolymer SEPS1: polystyrene-polyethylenepropylene-
Polystyrene triblock copolymer, manufactured by Kuraray Co., Ltd. (trade name "Septon 4033") SEPS2: polystyrene-polyethylene propylene-
Polystyrene triblock copolymer, manufactured by Kuraray Co., Ltd. (trade name "Septon 4055") Plasticizer: paraffin-based process oil, manufactured by Idemitsu Petrochemical Co., Ltd. (trade name "Diana Process Oil PW-90") Crosslinking agent: 2,5- Dimethyl-2,5-di (tert-
Butylperoxy) hexane, manufactured by NOF CORPORATION (trade name "Perhexa 25B") Crosslinking aid 1: Ethylene glycol dimethacrylate, manufactured by Kanto Chemical Co., Ltd. Crosslinking aid 2: triethylene glycol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. (Name “NK ester 3G”) (Production Example 1) [Production of styrene-isobutylene-styrene block copolymer (SIBS)] After the inside of the polymerization vessel of a 2 L separable flask was replaced with nitrogen, n- 456.1 mL of hexane (dried with molecular sieves) and 656.5 m of butyl chloride (dried with molecular sieves)
L, and the polymerization vessel was placed in a -70 ° C. dry ice / methanol bath and cooled, and then Teflon (registered trademark) was placed in a pressure-resistant glass liquefaction sampling tube equipped with a three-way cock containing 232 mL (2871 mmol) of isobutylene monomer. The liquid sending tube was connected, and the isobutylene monomer was sent into the polymerization vessel under nitrogen pressure. 0.647 g (2.8 mmol) of p-dicumyl chloride and 1.22 g (14 mmol) of N, N-dimethylacetamide were added. Next, 8.67 mL of titanium tetrachloride (79.1 m
mol) was added to initiate polymerization. 1.5 from the start of polymerization
After stirring at the same temperature for a period of time, about 1 mL of the polymerization solution was withdrawn from the polymerization solution for sampling. continue,
77.9 g (748 mmol) of a styrene monomer previously cooled to −70 ° C., 23.9 n-hexane
A mixed solution of mL and 34.3 mL of butyl chloride was added to the polymerization vessel. Forty-five minutes after the addition of the mixed solution, about 40 mL of methanol was added to terminate the reaction.

After distilling off the solvent and the like from the reaction solution, it was dissolved in toluene and washed twice with water. Further, a toluene solution was added to a large amount of methanol to precipitate a polymer, and the obtained polymer was vacuum-dried at 60 ° C. for 24 hours to obtain a target block copolymer. The molecular weight of the obtained polymer was measured by gel permeation chromatography (GPC). The Mn of the isobutylene polymer before styrene addition was 50,000 and Mw / Mn was 1.40, and the Mn of the block copolymer after styrene polymerization was 67,00.
0, and a block copolymer having Mw / Mn of 1.50 was obtained.

(Examples 1 to 7) SI manufactured in Production Example 1
BS, SEPS 1 or 2, and a plasticizer were melt-kneaded at a ratio shown in Table 1 using a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) set at 180 ° C for 5 minutes, and then a crosslinking agent and a crosslinking aid 1 or 2 were added. 2 was added at the ratio shown in Table 1, and the mixture was further melt-kneaded at 180 ° C. until the torque value reached the maximum value (3 to 7 minutes) to perform dynamic crosslinking. The obtained thermoplastic elastomer composition could be easily formed into a sheet at 180 ° C. The hardness, tensile strength at break, tensile elongation at break, and compression set of the obtained sheet were measured in accordance with the above methods. Table 1 shows the physical properties of each sheet.

(Comparative Example 1) SIBS produced in Production Example 1
Was melt-kneaded for 10 minutes using a Labo Plastomill set at 180 ° C., and then formed into a sheet at 180 ° C. The hardness of the obtained sheet, tensile strength at break, tensile elongation at break,
And compression set were measured according to the method described above. The physical properties of each sheet are shown in the table.

[0050]

[Table 1]

The thermoplastic elastomer compositions of the present invention, ie, Examples 1 to 7, were prepared using the hardness (JIS) of the isobutylene-based block copolymer SIBS alone shown in Comparative Example 1.
A: The value of compression set is lower than that of the SIBS alone, although the hardness is almost the same or higher than that of 47), and the compression set is reduced while maintaining the properties of the isobutylene-based block copolymer. It is clear that it is excellent. It can also be seen that the balance among hardness, strength, and compression set can be easily adjusted by the amount or type of the non-isobutylene-based block copolymer, plasticizer, crosslinking agent, and crosslinking aid.

[0052]

Industrial Applicability The thermoplastic elastomer composition of the present invention has high flexibility, moldability, rubber-like properties, mechanical strength, gas barrier properties and sealing while maintaining the properties of the isobutylene-based block copolymer. It is a novel thermoplastic elastomer composition having excellent properties, particularly excellent compression set properties.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F070 AA12 AA18 AA40 AB08 AC56 AE02 AE08 GA05 GB08 4J002 AE05Y BB17Y BL01Y BP01X BP03W EK006 FD02Y FD146

Claims (7)

[Claims] An isobutylene block copolymer (A) containing a polymer block (a) mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound, and a conjugated diene compound A thermoplastic elastomer composition comprising a crosslinked product (B) of a non-isobutylene-based block copolymer containing the polymer block (c) containing the above (b) and the above (b). (B) A polymer block (c) mainly composed of a conjugated diene compound and a polymer block (b) mainly composed of an aromatic vinyl compound, which are obtained by hydrogenation. The thermoplastic elastomer composition according to claim 1, which is a crosslinked product of a hydrogenated non-isobutylene-based block copolymer. (B) A polymer block (c) mainly composed of a conjugated diene compound and a polymer block (b) mainly composed of an aromatic vinyl compound, which are obtained by hydrogenation. The thermoplastic elastomer composition according to claim 1, which is a crosslinked product of a mixture of a hydrogenated non-isobutylene-based block copolymer and a non-hydrogenated non-isobutylene-based block copolymer. 4. A crosslinked product of a non-isobutylene-based block copolymer (B) which has been previously crosslinked before being mixed with the isobutylene-based block copolymer (A). The thermoplastic elastomer composition according to any one of the above. 5. The non-isobutylene block copolymer is dynamically crosslinked during melt-kneading of the isobutylene block copolymer (A) and the non-isobutylene block copolymer. 5. The thermoplastic elastomer composition according to item 1. 6. The thermoplastic elastomer composition according to claim 1, further comprising a plasticizer. 7. An isobutylene-based block copolymer (A)
Is a block copolymer comprising at least one polymer block (a) mainly composed of isobutylene and at least two polymer blocks (b) mainly composed of an aromatic vinyl compound. The thermoplastic elastomer composition according to any one of the above.