JP2003055528A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new thermoplastic elastomer composition having high flexibility and excellent in moldability and processability, rubber characteristics, mechanical strength, permanent compression set property or vibration-damping property. SOLUTION: This thermoplastic elastomer composition is obtained by compounding (A) an isobutylene-based block copolymer containing a polymer block mainly comprising isobutylene and a polymer block mainly comprising an aromatic vinyl-based compound with (B) an isobutylene-based polymer having an alkenyl group at the end and optionally (C) a reinforcing material which is at least one kind of polymer selected from polystyrenes and polyphenylenes.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel thermoplastic elastomer composition having excellent flexibility, moldability, rubber properties, mechanical strength, 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 insufficient.

[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 excellent rubber properties, mechanical strength and compression set properties.

[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 a terminal block. It is a thermoplastic elastomer composition obtained by blending with an isobutylene polymer (B) having an alkenyl group. The isobutylene-based polymer (B) having an alkenyl group at the terminal is preferably one having an allyl group introduced at the terminal by a substitution reaction of allyltrimethylsilane and chlorine at the terminal of the isobutylene-based polymer. Further, the thermoplastic elastomer composition may be an isobutylene-based block copolymer (A) and an isobutylene-based polymer (B) having an alkenyl group at the end during melt-kneading of the isobutylene-based polymer (B) having an alkenyl group at the end. Of the isobutylene-based polymer (B) having an alkenyl group at the terminal,
It may be pre-crosslinked before being mixed with the isobutylene block copolymer (A).

Regarding the structure of the block copolymer, the blocks constituting the above-mentioned isobutylene block copolymer (A) are mainly composed of a polymer block (a) mainly containing isobutylene and an aromatic vinyl compound. It is preferably a triblock copolymer having the structure (b)-(a)-(b).

The thermoplastic elastomer composition may further contain a reinforcing material (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 an isobutylene-based polymer (B) having an alkenyl group at the terminal, which is a thermoplastic elastomer composition.

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. The content of the (b)-(a)-(b) structure consisting of at least two blocks (b) is preferably 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. The term "isobutylene-based polymer (B) having an alkenyl group at the terminal" as used in the present invention means that isobutylene is 50% by weight or more, preferably 70% by weight or more, more preferably 9% by weight or more.
A block occupying 0% by weight or more. In the isobutylene-based polymer (B) having an alkenyl group at the terminal,
Monomers other than isobutylene are not particularly limited as long as they are cationically polymerizable monomer components, aromatic vinyls,
Examples thereof include aliphatic olefins, isoprene, butadiene, dienes such as divinylbenzene, vinyl ethers, and monomers such as β-pinene. These may be used alone or in combination of two or more.

The number average molecular weight of the isobutylene polymer (B) having an alkenyl group at the terminal is not particularly limited,
1,000 to 500,000 is preferable, 2,000
To 100,000 are particularly preferred. When the number average molecular weight is less than 1,000, mechanical properties and the like are not sufficiently exhibited, and when it exceeds 500,000, the moldability and the like are greatly reduced and the compression set improving effect is small. .

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 for introducing an alkenyl group into the terminal of the isobutylene-based polymer of the present invention, there is disclosed in JP-A-3-
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.

Further, the alkenyl group substituted at the terminal is 1
It is preferable that at least 0.2, more preferably 0.5 is present at the end of the molecule. If it is less than this range, a composition having excellent compression set cannot be obtained.

A thermoplastic elastomer composition composed of an isobutylene block copolymer (A) and an isobutylene polymer (B) having an alkenyl group introduced at the terminal is either a dynamically crosslinked one at the time of melt kneading or an alkenyl at the terminal. A composition obtained by previously crosslinking the isobutylene-based polymer (B) having a group introduced therein and further melt-mixing the isobutylene-based block copolymer (A) is preferable, and a dynamically crosslinked composition is particularly 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 polymer (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 or a crosslinking agent (D Alternatively, radical crosslinking can be carried out 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 polymer (B) having an alkenyl group introduced at the end 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, b represents 2 ≦ b ≦ 100, and c represents an integer satisfying 0 ≦ c ≦ 100.) A ring represented by the general formula (III) Siloxane;

[0024]

[Chemical 1]

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

[0026]

[Chemical 2]

(In the formula, g and h are integers, and 2≤g + h≤
50, 2 ≦ g and 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 is 1
It may have one or more aromatic rings. i is an integer of 0 ≦ i ≦ 5. ) The isobutylene polymer (B) having an alkenyl group introduced at the terminal and the cross-linking agent can be mixed at any ratio, but from the viewpoint of curability, the molar ratio of the alkenyl group to the hydrosilyl group is 0.2 to It is preferably in the range of 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 crosslinking reaction between the polymer (B) and the crosslinking agent (D) proceeds by mixing the two components and heating.
A hydrosilylation catalyst can be added to drive the reaction more quickly. 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 solids, alumina, silica, carbon black and the like in which platinum solids are dispersed, chloroplatinic acid, chloroplatinic acid and alcohols, aldehydes, 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 0.5 to 5 parts by weight with respect to 100 parts by weight of the isobutylene block copolymer when the organic peroxide is added.

The composition of the present invention may contain a crosslinking aid having an ethylenically unsaturated group in the crosslinking 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 preferably 20 parts by weight or less with respect to 100 parts by weight of the butyl group-containing isobutylene polymer (B). If it exceeds 20 parts by weight, gelation of the crosslinking aid tends to proceed,
There is also a cost problem.

In addition to the isobutylene block copolymer (A) and the terminal alkenyl group-containing isobutylene polymer (B), the composition of the present invention further contains a reinforcing material (C) in order to further improve the strength. ) May be added. As the reinforcing material (C), it is possible to use polyphenylene ether, polystyrene, a composition thereof, a reinforcing resin, an inorganic filler such as calcium carbonate, talc, mica, kaolin, silica, glass fiber, or carbon black. However, reinforcing resins composed of polyphenylene ether, polystyrene, and compositions thereof are preferred. These are 1
More than one species can be used. The addition of the reinforcing material improves the tensile strength of the thermoplastic elastomer composition, and also improves the compression set depending on the compounding amount and the type of the reinforcing material. In addition, the composition of the present invention further comprises a plasticizer, 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 polyphenylene Ether, polystyrene, P
PO, polyphenylene ether-polystyrene composition,
In addition to these, hindered phenol-based and hindered amine-based antioxidants, UV absorbers, light stabilizers, pigments,
Surfactants, reaction delay agents, flame retardants, fillers, reinforcing agents and the like can be appropriately added.

As the plasticizer, 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 paraffin-based, naphthene-based, and aromatic high-boiling petroleum components, but paraffin-based and naphthene-based oils that do not inhibit the crosslinking reaction are preferable. The liquid or low molecular weight synthetic softening agent is not particularly limited, but polybutene, hydrogenated polybutene, liquid polybutadiene, hydrogenated liquid polybutadiene,
Examples include poly-α-olefins. One or more kinds of these plasticizers can be used. The blending amount of the plasticizer is preferably 10 to 300 parts by weight with respect to 100 parts by weight of the isobutylene polymer (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. 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 10 to 300 parts by weight of an isobutylene polymer (B) having an alkenyl group introduced at the terminal. Section, reinforcing material (C) 0
To 100 parts by weight, more preferably 100 parts by weight of the isobutylene block copolymer (A), an isobutylene polymer (B) 50 having an alkenyl group introduced at the terminal.
˜150 parts by weight, a reinforcing material (C) 0 to 50 parts by weight, and a crosslinking agent (D). In this case, with respect to 100 parts by weight of the modified isobutylene block copolymer (B) having an alkenyl group introduced at the terminal, the cross-linking agent (D) was 0.1.
01 to 20 parts by weight, and the crosslinking aid is preferably 0 to 20 parts by weight.

The method for producing the thermoplastic elastomer composition of the present invention is not particularly limited, and includes an isobutylene block copolymer (A), an isobutylene polymer having an alkenyl group introduced at the terminal (B), and a case. Any method can be adopted as long as it can uniformly mix the above-mentioned components used according to 1.

When the isobutylene block copolymer (A) and the butyl group-containing isobutylene polymer (B) are melt-mixed, the butyl group-containing isobutylene polymer (B) is moved. When the thermoplastic elastomer composition of the present invention is produced by cross-linking, 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 until uniform with a melt kneading device such as, and then pelletizing, dry blending the pellets with a cross-linking agent and a cross-linking auxiliary agent, and then melt-kneading with a melt-kneading device such as an extruder, isobutylene-based A polymer is dynamically crosslinked to produce a thermoplastic elastomer composition comprising a crosslinked product of the isobutylene block copolymer (A) of the present invention and an isobutylene polymer (B) having an alkenyl group introduced at the terminal. Method. 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 isobutylene-based polymer (B) having an alkenyl group introduced at the terminal, and the isobutylene-based block copolymer (A) of the present invention having an alkenyl group introduced at the terminal. A method for producing a thermoplastic elastomer composition comprising a crosslinked product of the obtained isobutylene polymer (B) can be adopted.

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.

A crosslinked product of an isobutylene-based polymer (B) having an alkenyl group introduced at its terminal is prepared in advance, and the crosslinked product is mixed with the isobutylene-based block copolymer (A) to produce the thermoplastic resin of the present invention. When preparing an elastomer composition, the method illustrated below is preferably adopted.

For example, a kneader or the like which is usually used for producing a rubber cross-linked product is used by adding a cross-linking agent, a cross-linking aid and a cross-linking catalyst to the isobutylene polymer (B) having an alkenyl group introduced at the terminal. After sufficiently kneading at a suitable temperature, the resulting kneaded product is subjected to a crosslinking reaction by employing a suitable crosslinking temperature and a crosslinking time using a press or the like,
After cooling, the mixture is pulverized to obtain a crosslinked product of an isobutylene-based polymer (B) having an alkenyl group introduced at the terminal, and the crosslinked product is melt-mixed with the isobutylene-based block copolymer (A) to obtain the heat of the present invention. A plastic elastomer composition can be manufactured.

At this time, as a melt mixing method of the crosslinked product of the isobutylene polymer (B) having an alkenyl group introduced at the terminal and the isobutylene block copolymer (A), a thermoplastic resin or a thermoplastic elastomer composition is used. Any of the known methods conventionally used for the production of products can be adopted, for example, using Labo Plastomill, Banbury mixer, single-screw extruder, twin-screw extruder, or other melt-kneading equipment. The 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 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. Further, since the thermoplastic elastomer composition of the present invention is excellent in moldability and compression set characteristics, it is used as a sealing material for packing materials, sealing materials, gaskets, plugs, etc., dampers for light electric devices such as CD dampers, and construction. Dampers for automobiles, automobiles, vehicles, home appliances, etc., vibration damping materials, vibration damping materials, automobile interior materials, cushioning materials, daily necessities, electric parts,
It can be effectively used as electronic parts, sports parts, grips or cushioning materials, electric wire coating materials, wrapping 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.

(Dynamic viscoelasticity) In accordance with JIS K-6394 (Testing method for dynamic properties of vulcanized rubber and thermoplastic rubber), a test piece of 6 mm in length × 5 mm in width × 2 mm in thickness was cut out to obtain a dynamic viscoelasticity. The loss tangent tan δ was measured using an elasticity measuring device DVA-200 (manufactured by IT measurement control company). The measurement frequency was 0.05 Hz.

The abbreviations of the materials used in Examples and Comparative Examples and their specific contents are shown below. SIBS: polystyrene-polyisobutylene-polystyrene triblock copolymer APIB: polyisobutylene with an allyl group introduced at the terminal EP600A manufactured by Kaneka Corporation IIR: butyl rubber, manufactured by JSR (trade name "Butyl"
065 ") Reinforcing material: PPO Noryl EFN4230 (manufactured by Japan GE Plastics Co., Ltd.) Crosslinking agent 1: Average of 5 hydrosilyl groups and average of 5 in the 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) [Styrene-isobutylene-
Production of Styrene Block Copolymer (SIBS)] After replacing the inside of the polymerization vessel of a 2 L separable flask with nitrogen, using a syringe, 456.4 mL of n-hexane (dried with molecular sieves) and butyl chloride (molecular) (Dried with 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.

(Example 1) SIB produced in Production Example 1
S and APIB 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 at a ratio shown in Table 1. 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. The hardness, tensile strength at break, tensile elongation at break, compression set, and dynamic viscoelasticity of the obtained sheet were measured according to the methods described above. The results are shown in Table 1.

(Example 2) SIBS, APIB and a reinforcing material were mixed in the proportions shown in Table 1 and dynamically crosslinked in the same manner as in Example 1. The thermoplastic elastomer composition obtained had a composition of 1
It could be easily formed into a sheet at 80 ° C. 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 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 was measured according to the above method. The results are shown in Table 1.
Shown in.

(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) Using APIB, in the same manner as in Example 1, a composition was prepared in the proportions 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, and dynamic viscoelasticity were measured according to the above methods. The results are shown in Table 1.

[0062]

[Table 1]

The thermoplastic elastomer composition of the present invention comprises
It has a lower compression set value than SIBS which is the isobutylene block copolymer shown in Comparative Example 1, and is excellent in compression set while maintaining the properties of the isobutylene block copolymer. The cross-linked product shown in Comparative Example 2 was I
As compared with the case of using IR, it is clear that the hardness is comparable or soft, but the compression set value is excellent. Further, as compared with Comparative Example 4, it is clear that the thermoplastic elastomer composition of Example 1 has a high tan δ value and excellent vibration damping properties.

[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 having excellent vibration damping properties.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F070 AA12 AB08 AC76 AC84 GA01                       GA05 GA06                 4J002 BB18X BB20X BC034 BP03W                       CH074 CP033 DE236 DJ016                       DJ036 DJ046 DJ056 DL006                       FA046 FD014 FD016 FD020                       FD143 GC00 GJ02 GL00                       GN00 GQ00

Claims (10)

[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 an isobutylene polymer having an alkenyl group at a terminal. (B)
And a thermoplastic elastomer composition 2. The isobutylene-based polymer (B) having an alkenyl group at the terminal is one in which an allyl group is introduced into the terminal by a substitution reaction of allyltrimethylsilane and chlorine at the terminal of the isobutylene-based polymer. The thermoplastic elastomer composition. 3. A thermoplastic elastomer composition, wherein the isobutylene-based block copolymer (A) and the isobutylene-based polymer (B) having an alkenyl group at the terminal are melt-kneaded, and the isobutylene-based polymer having an alkenyl group at the terminal ( The thermoplastic elastomer composition according to claim 1 or 2, wherein B) is dynamically crosslinked. 4. The isobutylene-based polymer (B) having an alkenyl group at the terminal is a cross-linked product which is previously crosslinked before being mixed with the isobutylene-based block copolymer (A). The thermoplastic elastomer composition according to. 5. The block constituting the isobutylene block copolymer (A) is composed of a polymer block (a) mainly containing isobutylene and a polymer block (b) mainly containing an aromatic vinyl compound. , (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 reinforcing material (C).
5. The thermoplastic elastomer composition according to any one of 5 above. 7. The thermoplastic elastomer composition according to claim 6, wherein the reinforcing material (C) is at least one selected from polystyrene and polyphenylene ether. 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. An isobutylene block copolymer (A)
The thermoplastic elastomer composition according to any one of claims 1 to 9, which contains 10 to 300 parts by weight of the isobutylene-based polymer (B) having an alkenyl group introduced at the end, relative to 100 parts by weight. .