JP2003026895A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new thermoplastic elastomer composition which has flexibility and has excellent formability, rubbery characteristics, mechanical strength, compression permanent set, and a vibration-damping property. SOLUTION: This thermoplastic elastomer composition comprises (A) an isobutylene block copolymer comprising a polymer block consisting mainly of isobutylene and a polymer block consisting mainly of an aromatic vinyl compound and (B) a modified isobutylene block copolymer which comprises the block copolymer comprising isobutylene and an aromatic vinyl compound and having alkenyl groups at the terminals.

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, moldability, rubber properties, mechanical strength, transparency and compression set properties.

[0002]

2. Description of the Related Art Conventionally, as a polymeric material having elasticity, a rubber such as a natural rubber or a synthetic rubber mixed with a crosslinking agent or a reinforcing agent and crosslinked under high temperature and high pressure is generally used. However, such rubbers require a process of crosslinking and molding for a long time under high temperature and high pressure, and are inferior in processability. Further, since crosslinked rubber does not show thermoplasticity, recycling molding is generally impossible like thermoplastic resins. Therefore, in recent years, various thermoplastic elastomers have been developed that can easily produce molded products by using general-purpose melt molding techniques such as hot press molding, injection molding, and extrusion molding, similar to ordinary thermoplastic resins. ing. In addition, a soft vinyl chloride compound is widely used as a flexible material. It is used as a flexible material at room temperature in various applications, but due to the recent demand for dechlorination, substitution with other materials is required. Thermoplastic elastomer compositions have been used as alternative materials for this purpose. As such a thermoplastic elastomer, various types of polymers such as olefin-based, urethane-based, ester-based, styrene-based, and vinyl chloride-based polymers have been developed and are commercially available.

Of these, the styrene-based thermoplastic elastomer is rich in flexibility and excellent in rubber elasticity at room temperature. As the styrene-based thermoplastic elastomer,
Styrene-butadiene-styrene block copolymer (S
BS), styrene-isoprene-styrene block copolymer (SIS), and styrene obtained by hydrogenating them.
Ethylene butylene-styrene block copolymer (SEB
S) and styrene-ethylene propylene-styrene block copolymer (SEPS) have been developed. However, these block copolymers had insufficient compression set characteristics.

On the other hand, as a thermoplastic elastomer having excellent flexibility, excellent rubber elasticity at room temperature, gas barrier property and sealing property, a polymer block mainly containing isobutylene and an aromatic vinyl compound are used. An isobutylene-based block copolymer containing a polymer block mainly containing is known. However, this isobutylene-based block copolymer also has problems in the rate of pressure deformation during heating (compression set) and rubber elasticity at high temperatures.

Further, a thermoplastic polymer composition comprising an isobutylene block copolymer containing a polymer block mainly containing isobutylene and a crosslinked product of rubber is known (Republished Patent WO98 / 14518). This composition had improved compression set characteristics, but improved compression set, but was opaque and had an insufficient hardness-mechanical strength balance.

[0006]

In view of the above-mentioned problems of the prior art, the object of the present invention is to provide high flexibility, moldability,
It is intended to provide a thermoplastic elastomer composition having rubber properties, mechanical strength, transparency, and excellent compression set characteristics.

[0007]

Means for Solving the Problems That is, the present invention provides an isobutylene block copolymer (A) containing a polymer block mainly containing isobutylene and a polymer block mainly containing an aromatic vinyl compound, and isobutylene. A block copolymer containing a polymer block mainly composed of and a polymer block mainly composed of an aromatic vinyl compound, wherein a modified isobutylene block copolymer (B) having an alkenyl group at a terminal is blended. It is a thermoplastic elastomer composition obtained by The modified isobutylene-based block copolymer (B) is preferably one in which an allyl group is introduced into the terminal by a substitution reaction of allyltrimethylsilane and chlorine. As the thermoplastic elastomer composition, the modified isobutylene block copolymer (B) was dynamically cross-linked during melt-kneading of the isobutylene block copolymer (A) and the modified isobutylene block copolymer (B). The modified isobutylene-based block copolymer (B) may be a cross-linked one before being mixed with the isobutylene-based block copolymer (A).

As the structure of the block copolymer, the blocks constituting the above-mentioned isobutylene block copolymer (A) and / or modified isobutylene block copolymer (B) are polymer blocks mainly containing isobutylene. A triblock copolymer having (a) and a polymer block (b) mainly containing an aromatic vinyl compound and having a structure of (b)-(a)-(b) is preferable.

The thermoplastic elastomer composition may further contain a plasticizer (C) and may further contain a crosslinking agent (D).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic elastomer composition of the present invention comprises an isobutylene block copolymer (A) containing a polymer block mainly containing isobutylene and a polymer block mainly containing an aromatic vinyl compound. And a block copolymer containing a polymer block mainly containing isobutylene and a polymer block mainly containing an aromatic vinyl compound, the modified isobutylene block copolymer having an alkenyl group at a terminal (B) It is a thermoplastic elastomer composition obtained by blending and.

The isobutylene-based polymer block of the isobutylene block copolymer (A) of the present invention means that isobutylene accounts for 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more. Refers to a block. In the polymer block mainly composed of isobutylene, the monomer other than isobutylene is not particularly limited as long as it is a cationically polymerizable monomer component, but aromatic vinyls, aliphatic olefins, dienes, vinyl ethers , Β-pinene and the like can be exemplified. These may be used alone or in combination of two or more.

The isobutylene-based block copolymer (A) polymer block containing an aromatic vinyl compound as a main component means that the aromatic vinyl compound is 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight. A block that accounts for more than weight%. The monomer other than the aromatic vinyl compound in the polymer block mainly composed of the aromatic vinyl compound is not particularly limited as long as it is a cationically polymerizable monomer, but aliphatic olefins, dienes, vinyl ethers Examples thereof include monomers such as β-pinene and the like.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, β-methylstyrene, p-methylstyrene, t-butylstyrene, monochlorostyrene, dichlorostyrene, methoxystyrene and indene. Among the above compounds, styrene, α-methylstyrene, p
-Methylstyrene and indene are preferred, and 2 of them
You may choose more than one species.

There are no particular restrictions on the proportion of the polymer block (a) mainly containing isobutylene and the polymer block (b) mainly containing an aromatic vinyl compound in the isobutylene block copolymer (A). In consideration of the balance between physical properties and processability, the polymer block (a) mainly containing isobutylene is 95 to 20 parts by weight, and the polymer block (b) mainly containing an aromatic vinyl compound is 5 to 80 parts by weight. It is particularly preferable that the polymer block (a) mainly containing isobutylene is 90 to 60 parts by weight, and the polymer block (b) mainly containing an aromatic vinyl compound is 10 to 40 parts by weight.

The preferred structure of the isobutylene block copolymer (A) of the present invention is at least one polymer block (a) containing isobutylene as a main component, from the viewpoint of physical properties and processability of the resulting composition. A structure having at least two polymer blocks (b) mainly containing an aromatic vinyl compound is preferable. Although the structure is not particularly limited, for example, a triblock copolymer formed from (b)-(a)-(b), {(b)-
It is possible to use at least one kind selected from a multi-block copolymer having repeating (a)} units and a star-shaped polymer having a diblock copolymer consisting of (b)-(a) as an arm. . Further, in the isobutylene-based block copolymer (A), in addition to the above structure, a polymer mainly containing isobutylene, a polymer mainly containing an aromatic vinyl compound, and a diamine composed of (a)-(b) At least one kind of block copolymer may be contained. However, from the viewpoint of physical properties and processability, at least one of the polymer blocks (a) mainly containing isobutylene contained in the isobutylene block copolymer (A) and a polymer mainly containing an aromatic vinyl compound. It is preferable that the structure having at least two blocks (b) is 50% by weight or more.

The weight average molecular weight of the isobutylene block copolymer (A) is not particularly limited, but is preferably 30,000 to 500,000 and 40,000 to 40.
10,000 is especially preferred. Weight average molecular weight is 30,000
When it is less than 0, the mechanical properties and the like are not sufficiently expressed, and when it exceeds 500,000, the moldability and the like are largely deteriorated. In the present invention, a block copolymer containing a polymer block mainly composed of isobutylene and a polymer block mainly composed of an aromatic vinyl compound, a modified isobutylene block copolymer having an alkenyl group at a terminal (B) is an isobutylene block copolymer (A)
It is a product obtained by modifying the terminal of the copolymer shown in 1) with an alkenyl group. Therefore, the polymer block mainly containing isobutylene and the polymer block mainly containing an aromatic vinyl compound have the same molecular weight and the like as the components constituting the above-mentioned isobutylene block copolymer (A). Good or different. However, the polymer blocks mainly isobutylene, and the polymer blocks mainly aromatic vinyl compound, respectively,
The configurations may be the same or different.

The weight average molecular weight of the modified isobutylene block copolymer (B) is not particularly limited, but it is 1,0.
00 to 500,000 is preferable, 2,000 to 1
Especially preferred is 0,000. Weight average molecular weight is 100
When it is less than 0, the mechanical properties and the like are not sufficiently expressed, and when it exceeds 500,000, the moldability and the like are largely deteriorated.

The alkenyl group of the present invention is particularly limited as long as it is a group containing a carbon-carbon double bond which is active in the crosslinking reaction of the component (B) for achieving the object of the present invention. is not. Specific examples include vinyl groups, allyl groups, methylvinyl groups, propenyl groups, butenyl groups, pentenyl groups, aliphatic unsaturated hydrocarbon groups such as hexenyl groups,
Examples thereof include cyclic unsaturated hydrocarbon groups such as cyclopropenyl group, cyclobutenyl group, cyclopentenyl group and cyclohexenyl group.

As a method of introducing an alkenyl group into the terminal of the isobutylene block copolymer of the present invention, there is disclosed in Japanese Patent Laid-Open No.
A method of introducing an unsaturated group into a polymer by reacting a polymer having a functional group such as a hydroxyl group with a compound having an unsaturated group, as disclosed in JP-A-152164 and JP-A-7-304909, is disclosed. Can be mentioned. Further, in order to introduce an unsaturated group into a polymer having a halogen atom, a method of performing a Friedel-Crafts reaction with an alkenylphenyl ether, a method of performing a substitution reaction with allyltrimethylsilane in the presence of a Lewis acid, various phenols Examples of the method include a Friedel-Crafts reaction with and introducing a hydroxyl group, and then further performing the above-mentioned alkenyl group introducing reaction. Further, U.S. Pat. No. 4,316,973, JP-A-63-105.
It is also possible to introduce an unsaturated group at the time of polymerizing a monomer, as disclosed in Japanese Patent Laid-Open No. 005-005 and Japanese Patent Laid-Open No. 4-288309. Particularly, those having an allyl group introduced at the terminal by a substitution reaction with allyltrimethylsilane are preferable. Moreover, it is preferable that at least 0.2 alkenyl groups are substituted at the end of each molecule.
If it is less than this range, a composition having excellent compression set cannot be obtained.

The thermoplastic elastomer composition comprising the isobutylene block copolymer (A) and the modified isobutylene block copolymer (B) having an alkenyl group introduced at the terminal is a dynamically crosslinked one during melt kneading, or A composition obtained by previously cross-linking a modified isobutylene block copolymer (B) having an alkenyl group introduced at its terminal and further melt-mixing the isobutylene block copolymer (A) is preferable, and a dynamically cross-linked composition is particularly preferable. preferable.

The cross-linked product formed here includes a cross-linked product of (B) alone or a cross-linked product of (A) and (B) simultaneously contained in the cross-linked product. Of these, it is preferable that (B) alone form a crosslinked product.

As a means for crosslinking the isobutylene block copolymer (B) having an alkenyl group introduced at its terminal, a known method can be used without any particular limitation.
For example, thermal crosslinking by heating, crosslinking by a crosslinking agent (D),
Alternatively, radical crosslinking can be performed without using a crosslinking agent.

A hydrosilyl group-containing compound is preferably used as the cross-linking agent (D) for obtaining a cross-linked product of the isobutylene block copolymer (B) having an alkenyl group introduced at the terminal of the present invention. The hydrosilyl group-containing compound is not particularly limited and various compounds can be used. That is, linear polysiloxanes represented by the general formula (I) or _{^{(II); R 1 3 SiO-}} [Si (R 1) 2 O] a - [Si (H) (R 2) O] A - [ ^{Si (R 2) (R 3} ) O] B -SiR 1 3 (I) HR 1 2 SiO- [Si (R 1) 2 O] a - [Si (H) (R 2) O] A - [Si (R ² ) (R ³ ) O] _B —SiR ¹ ₂ H (II) (In the formula, R ¹ and R ² are an alkyl group having 1 to 6 carbon atoms or a phenyl group, and R ³ is 1 to 1 carbon atoms. 10 represents an alkyl group or an aralkyl group, a represents 0 ≦ a ≦ 100, A represents 2 ≦ A ≦ 100, and B represents an integer satisfying 0 ≦ B ≦ 100.) A ring represented by the general formula (III) Siloxane;

[0024]

[Chemical 1] (In the formula, R ⁴ and R ⁵ represent an alkyl group having 1 to 6 carbon atoms or a phenyl group, and R ⁶ represents an alkyl group having 1 to 10 carbon atoms or an aralkyl group. C represents 0 ≦ C ≦ 8, e Is 2 ≦
e ≦ 10 and f represent an integer of 0 ≦ f ≦ 8, and 3 ≦ C +
e + f ≦ 10 is satisfied. ) Etc. can be used. Further, among the above-mentioned compounds having a hydrosilyl group (Si—H group), those represented by the following general formula (IV) are particularly preferable from the viewpoint of good compatibility with the component (B).

[0025]

[Chemical 2] (In the formula, g and h are integers and 2 ≦ g + h ≦ 50, 2 ≦
g, 0 ≦ h. R ⁷ represents a hydrogen atom or a methyl group, and R ⁸ is a hydrocarbon group having 2 to 20 carbon atoms and may have one or more aromatic rings. i is an integer of 0 ≦ i ≦ 5.

The modified isobutylene block copolymer (B) having an alkenyl group introduced at its terminal and the cross-linking agent can be mixed in any proportion, but from the viewpoint of curability, the molar ratio of the alkenyl group to the hydrosilyl group. Is preferably in the range of 0.2 to 5, and more preferably 0.4 to 2.5. When the molar ratio is 5 or more, sufficient crosslinking cannot be obtained due to insufficient crosslinking, and when it is less than 0.2, a large amount of active hydrosilyl groups remain in the composition even after crosslinking, so that the composition is uniform. Therefore, a strong composition cannot be obtained.

The cross-linking reaction between the copolymer (B) and the cross-linking agent (D) proceeds by mixing the two components and heating, but a hydrosilylation catalyst is added to accelerate the reaction. be able to. Such a hydrosilylation catalyst is not particularly limited, and examples thereof include radical initiators such as organic peroxides and azo compounds, and transition metal catalysts.

The radical initiator is not particularly limited,
For example, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane,
Such as 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne, dicumyl peroxide, t-butylcumyl peroxide, α, α′-bis (t-butylperoxy) isopropylbenzene Dialkyl peroxides such as dialkyl peroxides, benzoyl peroxides, p-chlorobenzoyl peroxides, m-chlorobenzoyl peroxides, 2,4-dichlorobenzoyl peroxides, lauroyl peroxides, peracid esters such as perbenzoic acid-t-butyl, perdialkyl peroxides. Peroxydicarbonates such as diisopropyl carbonate, di-2-ethylhexyl perdicarbonate, 1,1-di (t-butylperoxy) cyclohexane, 1,1-di (t-butylperoxy) -3,3,5-trimethyl Peroxyke like cyclohexane It can be mentioned Lumpur and the like.

The transition metal catalyst is also not particularly limited, and examples thereof include platinum solid, alumina, silica, carbon black or the like in which platinum solid is dispersed, chloroplatinic acid, chloroplatinic acid and alcohol, aldehyde, Examples thereof include complexes with ketones, platinum-olefin complexes, and platinum (0) -diallyltetramethyldisiloxane complexes. Examples of catalysts other than platinum compounds include RhCl (PPh ₃ ) ₃ , R
hCl ₃ , RuCl ₃ , IrCl ₃ , FeCl ₃ , AlCl
₃ , PdCl ₂ · H ₂ O, NiCl ₂ , TiCl _{4 and the} like. These catalysts may be used alone or in combination of two or more kinds. The amount of the catalyst is not particularly limited, but it is 1 per 1 mol of the alkenyl group of the component (B).
It is preferably used in the range of 0 ^-1 to 10 ^-8 mol, and more preferably in the range of 10 ^-3 to 10 ^-6 mol. 10
^If it is less than ^-8 mol, curing will not proceed sufficiently. Since the hydrosilylation catalyst is expensive, it is preferable not to use more than 10 ^-1 mol. Of these, platinum allyl siloxane is most preferable in terms of compatibility, crosslinking efficiency, and scorch stability.

For radical crosslinking, it is preferable to share a catalyst. A radical initiator such as an organic peroxide is used as the catalyst. The radical initiator is not particularly limited and includes, for example, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di ( t-butylperoxy) -3-hexyne, dicumyl peroxide, t-butylcumyl peroxide, α, α ′
Dialkyl peroxides such as bis (t-butylperoxy) isopropylbenzene, benzoyl peroxide, p-chlorobenzoyl peroxide, m-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diacyl peroxides such as lauroyl peroxide, perbenzoic acid Peresters such as -t-butyl, diisopropyl percarbonate, di-2-percarbonate
Peroxydicarbonate, such as ethylhexyl,
1,1-di (t-butylperoxy) cyclohexane,
Mention may be made of peroxyketals such as 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane. Of these, 2,5-dimethyl-2,5-dimethyl ether is preferable in terms of odor, coloring and scorch stability.
Di- (tert-butylperoxy) hexane, 2,5
-Dimethyl 2,5-di- (tert-butylperoxy) hexyne-3 is preferred.

The content of the organic peroxide is preferably in the range of 0.5 to 5 parts by weight based on 100 parts by weight of the isobutylene block copolymer at the time of adding the organic peroxide.

The composition of the present invention may contain a cross-linking aid having an ethylenically unsaturated group in the cross-linking treatment with an organic peroxide. The ethylenically unsaturated group, for example, a polyfunctional vinyl monomer such as divinylbenzene, triallyl cyanurate, or ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate,
Examples thereof include polyfunctional methacrylate monomers such as polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate.
These may be used alone or in combination of at least two kinds. With such a compound, a uniform and efficient crosslinking reaction can be expected.

Among them, ethylene glycol dimethacrylate and triethylene glycol dimethacrylate are particularly easy to handle and have a peroxide solubilizing effect,
Since it works as a dispersion aid of peroxide, the crosslinking effect by heat treatment is uniform and effective, and a crosslinked thermoplastic elastomer having a well-balanced hardness and rubber elasticity can be obtained, which is preferable.

The amount of the above-mentioned crosslinking aid added is 20 with respect to 100 parts by weight of the modified isobutylene block copolymer (B).
It is preferably less than or equal to parts by weight. If it exceeds 20 parts by weight, the gelling of the crosslinking aid tends to proceed easily, and there is a problem in terms of cost.

In addition to the isobutylene block copolymer (A) and the modified isobutylene block copolymer (B) having an alkenyl group at the terminal, the composition of the present invention further improves moldability and flexibility. For further plasticizer (C)
Can also be added. As the plasticizer (C), a mineral oil used in the processing of rubber or a liquid or low molecular weight synthetic softening agent can be used.

Examples of the mineral oil include high-boiling petroleum components of paraffin type, naphthene type and aromatic type, but paraffin type and naphthene type which do not inhibit the crosslinking reaction are preferable. The liquid or low molecular weight synthetic softening agent is not particularly limited, and examples thereof include polybutene, hydrogenated polybutene, liquid polybutadiene, hydrogenated liquid polybutadiene, and poly α-olefins. One or more of these plasticizers (C) can be used. The blending amount of the plasticizer (C) is preferably 10 to 300 parts by weight with respect to 100 parts by weight of the isobutylene block copolymer (B) having an alkenyl group introduced at the terminal. If the blending amount exceeds 300 parts by weight, mechanical strength is lowered and moldability is problematic. In addition, the composition of the present invention further comprises a reinforcing agent, a filler such as styrene-butadiene-styrene block copolymer (SBS) or styrene, depending on the required properties according to each application, as long as the physical properties are not impaired. -Isoprene-styrene block copolymer (SIS), elastomers such as hydrogenated styrene-ethylene butylene-styrene block copolymer (SEBS) and styrene-ethylene propylene-styrene block copolymer (SEPS), and others Also, a hindered phenol-based or hindered amine-based antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, a surfactant, a reaction retarder, a flame retardant, a filler, a reinforcing agent and the like can be appropriately mixed.

The most preferable composition of the thermoplastic elastomer composition of the present invention is 100 parts by weight of the isobutylene block copolymer (A), and a modified isobutylene block copolymer ( B) 10 to 300 parts by weight, plasticizer (C) 0 to 100 parts by weight, and more preferably modified isobutylene-based block in which an alkenyl group is introduced at the end with respect to 100 parts by weight of the isobutylene-based block copolymer (A). Copolymer (B)
It is a composition containing 50 to 150 parts by weight, 0 to 50 parts by weight of a plasticizer (C) and a crosslinking agent (D). In this case, the crosslinking agent (D) is 0.01 to 20 parts by weight and the crosslinking aid is 0 to 20 parts by weight with respect to 100 parts by weight of the modified isobutylene-based block copolymer (B) having an alkenyl group introduced at the terminal. Is preferred.

The method for producing the thermoplastic elastomer composition of the present invention is not particularly limited, and includes isobutylene type block copolymer (A) and modified isobutylene type block copolymer (B) having an alkenyl group introduced at the terminal. Any method can be adopted as long as it is a method capable of uniformly mixing the above-mentioned components used in some cases.

When the isobutylene-based block copolymer (A) and the modified isobutylene-based block copolymer (B) having an alkenyl group introduced at the terminal are melt-mixed, the modified isobutylene-based block copolymer having an alkenyl group introduced at the terminal is mixed. When the thermoplastic elastomer composition of the present invention is produced by dynamically crosslinking the united product (B), it can be preferably carried out by the method exemplified below.

For example, in the case of using a closed type kneading device such as Labo Plastomill, a Brabender, a Banbury mixer, a kneader, a roll or the like, or a batch type kneading device, a cross-linking agent and a cross-linking auxiliary agent, other than a cross-linking catalyst are used. It is possible to adopt a method in which all the components are mixed in advance and melt-kneaded until they are uniform, and then a crosslinking agent, a cross-linking aid, and a cross-linking catalyst are added to the cross-linking reaction to sufficiently stop the melt-kneading. it can.

Further, in the case of manufacturing using a continuous melt-kneading device such as a single-screw extruder or a twin-screw extruder, all components other than the crosslinking agent, the crosslinking aid, and the crosslinking catalyst are extruded in advance. Melt-kneading with a melt-kneading device such as to form pellets, dry-blending the pellets with a cross-linking agent, a cross-linking aid, and a cross-linking catalyst, and then melt-kneading with a melt-kneading device such as an extruder to obtain non-isobutylene Thermoplastic comprising a crosslinked product of the isobutylene type block copolymer (A) of the present invention and a modified isobutylene type block copolymer (B) in which an alkenyl group is introduced at the end, which is dynamically crosslinked A method for producing an elastomer composition.
Alternatively, all components other than the cross-linking agent (D), the cross-linking auxiliary agent, and the cross-linking catalyst are melt-kneaded by a melt-kneading device such as an extruder, and the cross-linking agent, the cross-linking auxiliary agent, and the cross-linking catalyst are added from the middle of the cylinder of the extruder. Is added and melt-kneaded to dynamically crosslink the modified isobutylene-based block copolymer (B) having an alkenyl group introduced at the terminal, and the isobutylene-based block copolymer (A) of the present invention is alkenyl-terminated. A method of producing a thermoplastic elastomer composition comprising a crosslinked product of a modified isobutylene block copolymer (B) having a group introduced therein can be employed.

In carrying out the above method of carrying out dynamic cross-linking simultaneously with melt-kneading, a temperature of 150 to 210 ° C. is preferable. Further, in this case, the isobutylene-based block copolymer (A) does not cause a crosslinking reaction, and only the modified isobutylene-based block copolymer (B) having an alkenyl group introduced at the terminal can be crosslinked.

A crosslinked product of the modified isobutylene block copolymer (B) in which an alkenyl group has been introduced at the terminal is prepared in advance, and the crosslinked product is mixed with the isobutylene block copolymer (A) to prepare a product. When preparing the thermoplastic elastomer composition of the invention, the methods exemplified below are preferably employed.

For example, a cross-linking agent, a cross-linking aid, and a cross-linking catalyst are added to the above-mentioned modified isobutylene block copolymer having an alkenyl group introduced at the terminal, and a kneading machine or the like usually used for producing a cross-linked rubber is used. Then, the mixture is sufficiently kneaded at an appropriate temperature, and the obtained kneaded product is allowed to undergo a crosslinking reaction by using an appropriate crosslinking temperature and a crosslinking time using a press or the like. A crosslinked product of a modified isobutylene block copolymer (B) having a group introduced therein is obtained, and the crosslinked product is melt-mixed with the isobutylene block copolymer (A) to give the thermoplastic elastomer composition of the present invention. It can be manufactured.

At this time, as a melt mixing method of the crosslinked product of the modified isobutylene block copolymer (B) having an alkenyl group introduced at the terminal and the isobutylene block copolymer (A), a thermoplastic resin or a thermosetting resin is used. Any of the known methods conventionally used for producing a plastic elastomer composition can be adopted, for example, using a Labo Plastomill, a Banbury mixer, a single-screw extruder, a twin-screw extruder, or another melt-kneading device. And the melt-kneading temperature is 150 to 2
10 ° C is preferred.

The thermoplastic elastomer composition of the present invention comprises
The thermoplastic resin composition can be molded by using a molding method and a molding device generally adopted, and for example, melt molding can be performed by extrusion molding, injection molding, press molding, blow molding or the like. In addition, since the thermoplastic elastomer composition of the present invention is excellent in moldability and compression set characteristics, sealing materials such as packing materials, sealing materials, gaskets, plugs, CD dampers, construction dampers, automobiles, vehicles. , Vibration damping materials for home appliances, vibration damping materials, automobile interior materials,
It can be effectively used as a cushion material, daily necessities, electric parts, electronic parts, sports materials, grips or cushioning materials, electric wire coating materials, packaging materials, various containers, and stationery parts.

[0047]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto. In addition, prior to the examples, various measuring methods, evaluation methods,
Examples will be described.

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

(Tensile rupture strength) According to JIS K 6251, the test piece is a 2 mm thick press sheet, and is 3 with a dumbbell.
I used it after punching it out into a No. The pulling speed was 500 mm / min.

(Tensile Breaking Elongation) According to JIS K 6251, the test piece is a 2 mm thick press sheet, and is 3 with a dumbbell.
I used it after punching it out into a No. The pulling speed was 500 mm / min.

(Compression set) According to JIS K 6262, a 12.0 mm thick press sheet was used as a test piece. It was measured under the conditions of 70 ° C. × 22 hours and 25% deformation. (Transparency) A 2 mm-thick press sheet was prepared, and the sheet was visually observed. When the back side was visible through the sheet, the back side was transparent, and the invisible one was opaque. (Dynamic viscoelasticity) According to JIS K-6394 (Dynamic property test method for vulcanized rubber and thermoplastic rubber), length 6 mm
A test piece measuring 5 mm in width and 5 mm in width and 2 mm in thickness was cut out, and a dynamic viscoelasticity measuring device DVA-200 (manufactured by IT measurement control company)
Was used to measure the loss tangent tan δ. The measurement frequency was 0.05 Hz. Further, the abbreviations of the materials used in Examples and Comparative Examples below and their specific contents are as follows. SIBS: Polystyrene-polyisobutylene-polystyrene triblock copolymer ASIBS: Modified polystyrene-polyisobutylene-polystyrene triblock copolymer having an alkenyl group introduced at the terminal. IIR: Butyl rubber, manufactured by JSR (trade name "Butyl
065 ") Plasticizer: Paraffin-based process oil, manufactured by Idemitsu Petrochemical Co., Ltd. (trade name" Diana Process Oil PW-90 ") Crosslinking agent 1: Average of 5 hydrosilyl groups and average of 5 in molecule.
Chain Siloxane Cross-Linking Agent Containing One α-Methyl Styrene Group 2: Reactive Brominated Alkyl Phenol Formaldehyde Compound, Taoka Kagaku Kogyo Co., Ltd. (Brand Name “Takkyrol 250-1”) Cross-linking Aid 1: Triethylene glycol dimethacrylate , Shin-Nakamura Chemical Co., Ltd. (trade name "NK Ester 3G") Cross-linking aid 2: Zinc oxide cross-linking catalyst: 1,1,3,3-tetramethyl- of zero-valent platinum
1,3-Diallyldisiloxane complex 1% xylene solution (Production Example 1) [Production of styrene-isobutylene-styrene block copolymer (SIBS)] The interior of a 2 L separable flask was replaced with nitrogen, and then a syringe was used. Using, n-hexane (dried with molecular sieves) 456.4 mL and butyl chloride (dried with molecular sieves) 656.3 m
L was added, the polymerization container was placed in a dry ice / methanol bath at -70 ° C. and cooled, and then a pressure-resistant glass liquefaction sampling tube with a three-way cock containing 232 mL (2871 mmol) of isobutylene monomer was made of Teflon (registered trademark). A liquid-feeding tube was connected, and the isobutylene monomer was fed into the polymerization container by 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, a further 8.67 mL of titanium tetrachloride (79.1 m
(mol) was added to initiate polymerization. 2.5 from the start of polymerization
After stirring at the same temperature for an hour, about 1 mL of the polymerization solution was withdrawn from the polymerization solution for sampling. continue,
77.9 g (748 mmol) of styrene monomer that had been cooled to -70 ° C in advance, n-hexane 14.1
A mixed solution of mL and 20.4 mL of butyl chloride was added into the polymerization vessel. Two hours after the addition of the mixed solution, a large amount of water was added to terminate the reaction.

The reaction solution was washed twice with water, the solvent was evaporated,
The target block copolymer was obtained by vacuum-drying the obtained polymer at 60 ° C. for 24 hours. The molecular weight of the polymer obtained by the gel permeation chromatography (GPC) method was measured. Mw of block copolymer is 1
A block copolymer of 01,000 was obtained.

(Production Example 2) [Production of Modified Polystyrene-Polyisobutylene-Polystyrene Triblock Copolymer (ASIBS) Introduced with Alkenyl Group at Terminal] After purging the inside of the polymerization vessel of a 2 L separable flask with nitrogen, Using a syringe, add 480 mL of n-hexane (dried with molecular sieves) and 690 mL of butyl chloride (dried with molecular sieves),
After the polymerization container was placed in a -70 ° C dry ice / methanol bath and cooled, 201 mL of isobutylene monomer was added.
A Teflon (registered trademark) feed tube was connected to a pressure-resistant glass liquefaction collection tube with a three-way cock containing (2132 mmol), and isobutylene monomer was fed into the polymerization vessel by nitrogen pressure. p- Diquamilolide 2.6
g (11.2 mmol) and N, N-dimethylacetamide 1.22 g (14 mmol) were added. Next, 9.9 mL (90.0 mmol) of titanium tetrachloride was further added to initiate polymerization. After stirring at the same temperature for 1.5 hours from the start of the polymerization, about 1 mL of the polymerization solution was sampled from the polymerization solution for sampling. Subsequently, 52 g (499 mmol) of styrene monomer was added into the polymerization container. 45 minutes after the addition of the mixed solution, 12 ml (10.0 mmol) of allyltrimethylsilane was added. After stirring at the same temperature for 60 minutes, a large amount of water was added to terminate the reaction.

The reaction solution was washed twice with water, the solvent was evaporated,
The target block copolymer was obtained by vacuum-drying the obtained polymer at 60 ° C. for 24 hours. The molecular weight of the polymer obtained by the gel permeation chromatography (GPC) method was measured. Mw of block copolymer is 2
A block copolymer of 2500 was obtained.

Example 1 SIB produced in Production Example 1
S and ASIBS produced in Production Example 2 were melt-kneaded at a ratio shown in Table 1 for 5 minutes using a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) set at 150 ° C., and then a crosslinking agent was added in Table 1.
The mixture was added at the ratio shown in Table 1, and kneading was continued for 5 minutes. A crosslinking catalyst was added, and the mixture was melt-kneaded to perform dynamic crosslinking. The obtained thermoplastic elastomer composition could be easily molded into a sheet at 180 ° C. Of the obtained sheet,
Hardness, tensile strength at break, tensile elongation at break, compression set, transparency, and dynamic viscoelasticity were measured according to the methods described above.
The results are shown in Table 1.

(Example 2) Dynamic crosslinking was carried out in the same manner as in Example 1 except for the composition ratio of SIBS and ASIBS. The obtained thermoplastic elastomer composition could be easily molded into a sheet at 180 ° C. The obtained sheet, hardness, tensile breaking strength, tensile breaking elongation, and compression set,
Transparency was measured according to the method described above. The results are shown in Table 1.

(Example 3) SIBS and ASIBS were melt-kneaded at a ratio shown in Table 1 for 5 minutes using a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) set at 150 ° C, and then a plasticizer was added. The mixture was added in the ratio shown in 1 and kneaded continuously for 5 minutes. The cross-linking agent was added at the ratio shown in Table 1, and the mixture was further kneaded for 5 minutes. A crosslinking catalyst was added, and the mixture was melt-kneaded to perform dynamic crosslinking. The obtained thermoplastic elastomer composition could be easily molded into a sheet at 180 ° C.
The hardness, compression set and transparency of the obtained sheet were measured according to the methods described above. The results are shown in Table 1.

(Example 4) A sheet was prepared in the same manner as in Example 3 except that the blending ratio was changed. Of the obtained sheet,
Hardness, compression set and transparency were measured according to the methods described above. The results are shown in Table 1.

(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 obtained sheet, hardness, tensile strength at break, tensile elongation at break,
The compression set and the transparency were measured according to the above methods. The results are shown in Table 1.

(Comparative Example 2) SIBS produced in Production Example 1,
IIR was melt-kneaded at a ratio shown in Table 1 for 5 minutes using a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) set at 180 ° C., and then a cross-linking agent 2, a cross-linking auxiliary agent 3 and a cross-linking auxiliary agent 4 were displayed. 1 was added at a 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 thermoplastic elastomer composition obtained was 180
It could be easily formed into a sheet at ℃. The hardness, tensile strength at break, tensile elongation at break, and compression set of the obtained sheet were measured according to the methods described above. The results are shown in Table 1.

(Comparative Example 3) ASIBS produced in Production Example 2
Was used in the same manner as in Example 1 to prepare a composition in the ratio shown in Table 1. However, it was not possible to obtain a sheet-shaped molded product using this composition.

Comparative Example 4 Lavalon SJ54 manufactured by Mitsubishi Chemical Corporation
A sheet was prepared using 00N, and the hardness, tensile strength at break, tensile elongation at break, compression set, transparency, and dynamic viscoelasticity were measured according to the above methods. The results are shown in Table 1.

[0063]

[Table 1] The thermoplastic elastomer composition of the present invention has a lower compression set value than SIBS which is the isobutylene block copolymer shown in Comparative Example 1, and retains the properties of the isobutylene block copolymer while maintaining the compression set. It has excellent distortion. When compared with the case where IIR is used for the crosslinked product shown in Comparative Example 2, the thermoplastic elastomer composition shown in Example 3.4 has the same hardness or softness, but is excellent in the value of compression set. It is clear that In addition, it is clear that the thermoplastic elastomer composition of Example 1 has a high tan δ value and is superior in damping and damping as compared with Comparative Example 4.

[0064]

As described above, the thermoplastic elastomer composition is rich in flexibility, moldability, rubber property, mechanical strength, compression set property while maintaining the characteristics of the isobutylene block copolymer. A novel thermoplastic elastomer composition excellent in vibration damping.

Continued front page    F-term (reference) 4F070 AA12 AA18 AB07 AB08 AB09                       AB11 AB16 AC92 AE08 GA01                       GA05 GB08                 4J002 AE05Y BP03W BP03X CP04Z                       FD14Z                 4J026 HA02 HB05 HB50 HE02

Claims (11)

[Claims] 1. An isobutylene block copolymer (A) containing a polymer block mainly containing isobutylene and a polymer block mainly containing an aromatic vinyl compound, and a polymer block mainly containing isobutylene and an aromatic substance. A block copolymer containing a polymer block containing a vinyl group-based compound as a main component, the thermoplastic elastomer composition comprising a modified isobutylene block copolymer (B) having an alkenyl group at the terminal. 2. The thermoplastic elastomer composition according to claim 1, wherein the modified isobutylene block copolymer (B) has an allyl group introduced at the terminal by a substitution reaction of allyltrimethylsilane and chlorine. 3. A thermoplastic elastomer composition, wherein a modified isobutylene-based block copolymer (B) is dynamically added during melt-kneading of the isobutylene-based block copolymer (A) and the modified isobutylene-based block copolymer (B). The thermoplastic elastomer composition according to claim 1 or 2, which is crosslinked. 4. The modified isobutylene block copolymer (B) is crosslinked in advance before being mixed with the isobutylene block copolymer (A), according to claim 1 or 2. Thermoplastic elastomer composition. 5. The block constituting the isobutylene block copolymer (A) and / or the modified isobutylene block copolymer (B) is a polymer block (a) mainly containing isobutylene and an aromatic vinyl group. A polymer block (b) containing a compound as a main component, and (b)-(a)-
The thermoplastic elastomer composition according to claim 1, which is a triblock copolymer having the structure of (b). 6. The method according to claim 1, further comprising a plasticizer (C).
5. The thermoplastic elastomer composition according to any one of 5 above. 7. The plasticizer (C) is at least one selected from paraffinic and naphthenic mineral oils.
The thermoplastic elastomer composition described. 8. The method according to claim 1, further comprising a cross-linking agent (D).
7. The thermoplastic elastomer composition according to any one of 7. 9. The thermoplastic elastomer composition according to claim 8, wherein the crosslinking agent (D) is a compound containing a hydrosilyl group. 10. The modified isobutylene block copolymer (B) has a weight average molecular weight of 1,000 to 500,000 and is a block copolymer having at least 0.2 alkenyl groups at each terminal. Item 6. A thermoplastic elastomer composition according to any one of items 1 to 5. 11. An isobutylene block copolymer (A)
10 to 3 parts by weight of the modified isobutylene block copolymer (B) in which an alkenyl group is introduced at the end is added to 100 parts by weight.
The thermoplastic elastomer composition according to claim 1, wherein the thermoplastic elastomer composition contains 100 parts by weight.