JP2001114974A - Polymer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer composition which has a high vibration-damping capability, is excellent in softness and resistances to ozone and aging, is recyclable, and has a low gas permeability. SOLUTION: This composition contains a polymer (A) which is an isobutylene/styrene block copolymer and a polymer (B) which is a bromination product of p-methylstyrene/isobutylene copolymer, provided that polymer A is in the unvulcanized state and polymer B is in the vulcanized state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer composition having a high damping performance, a low gas permeability, a good compression set, and requiring no vulcanization step.

[0002]

2. Description of the Related Art Vibration damping / anti-vibration rubber members control vibrations generated from motors such as refrigerators and washing machines, or record / reproduce equipment such as compact disks (CD) and mini disks (MD), and CD-ROMs. Recording of ROM, digital video disk (DVD), magneto-optical disk (MO), etc.
A polymer composition used to prevent vibration from being transmitted to a drive device in a playback device, and which is used as a material for the vibration-damping and vibration-isolating rubber members, is required to have excellent vibration damping ability. ing.

[0003] The seismic isolation rubber member and the seismic isolation bearing structure are
For example, it is used to attenuate the vibration applied to these buildings at the foundation of buildings such as houses, buildings, bridges, etc. The polymer compositions used as these materials include the same as described above. Excellent vibration damping capacity is required.
Furthermore, the outer shell of the seismic isolation bearing structure minimizes the permeation of oxygen, which can promote its aging, and imparts vibration damping capability to the outer shell itself to increase the damping capacity of the entire structure. It is desired to do.

[0004]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. 7-29221
No. 0 discloses a composition obtained by dynamically vulcanizing a rubber and a block copolymer of isoprene and styrene, as a material having an excellent vibration damping ability.

The above composition has a so-called sea-phase in which a block copolymer of isoprene and styrene having a property as a thermoplastic resin is present as a continuous phase, and a vulcanized rubber component is dispersed in the phase. It has an island structure, and has properties as a thermoplastic elastomer as a whole composition. For this reason, there is an advantage that molding and processing can be performed easily and in a short time by injection molding or the like without going through a vulcanizing step which requires a relatively long time.

[0006] However, in the above composition, a double bond which causes ozone deterioration and aging is present in the molecule.
Low ozone resistance and aging resistance.

[0007] In addition, block copolymers of isoprene and styrene (particularly those having a high content of vinyl isoprene units) have high hardness at room temperature and cannot be applied to applications requiring flexibility. is there. In addition, the said vinyl isoprene unit is a polyisoprene unit, isoprene is not a normal 1, 4- bond,
A portion forming a 1,2-bond or a 3,4-bond.

In order to lower the hardness of the block copolymer of isoprene and styrene to impart flexibility, there is a method of adding a large amount of oil. However, in this case, problems such as bleeding and migration of oil due to contact with other plastics may occur.

On the other hand, JP-A-9-25370 discloses that
An elastomer containing a thermoplastic engineering plastic such as nylon together with a brominated product of a copolymer of p-methylstyrene and isobutylene and a dynamic vulcanizate of a thermoplastic olefin-based polymer such as polyethylene and polypropylene has been disclosed. I have.

The bromide of a copolymer of p-methylstyrene and isobutylene (hereinafter referred to as "polymer (B)") used in the elastomer is tan δ at room temperature.
Is about 0.4, which is a relatively high value for an elastomer. Furthermore, since this polymer (B) has no double bond in the main chain, it has the advantage of being excellent in ozone resistance and aging resistance.

However, in thermoplastic engineering plastics such as nylon, tan δ is usually 0.1.
Since it is a very low level of about 1 to 0.15,
The vibration damping ability of the entire elastomer disclosed in the above publication is insufficient. Further, there is a problem that the elastomer has an extremely high hardness and insufficient flexibility.

Accordingly, the present invention is a polymer composition which replaces the composition and elastomer disclosed in the above publication, and has excellent vibration damping ability, excellent heat resistance, ozone resistance, aging resistance and flexibility, What can be molded by injection molding is required.

Further, in recent years, as concerns about environmental problems relating to waste disposal and the problem of effective use of resources have been increasing, it has become possible to repeatedly use vibration-damping / vibration-proof rubber members by recycling. It has been demanded.

Further, in addition to having the basic performance required for a vibration-damping / vibration-proof rubber member such as excellent vibration damping ability, for example, when the rubber member is used for a casing of the above-mentioned seismic isolation bearing structure, etc. In addition, it is required that the gas permeability is low as an added value. In this regard, the above block copolymer of isoprene and styrene (specifically, styrene-vinyl isoprene-styrene and the like) has a problem that gas permeability is large.

Accordingly, an object of the present invention is to provide a polymer composition having high vibration damping ability, excellent ozone resistance, aging resistance and flexibility, and which is further recyclable and has low gas permeability. To provide.

[0016]

Means for Solving the Problems and Effects of the Invention The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and have found that a block copolymer of isobutylene and styrene, p-methylstyrene After mixing with a bromide of a copolymer of styrene and isobutylene, by dynamic vulcanization, p-methylstyrene in a vulcanized state is mixed with isobutylene-styrene block copolymer (polymer (A)). When a bromide copolymer (polymer (B)) with isobutylene is dispersed to form a so-called sea-island structure, it has high vibration damping ability and excellent ozone resistance, aging resistance and flexibility. In addition, the present inventors have found a new fact that a polymer composition which can be recycled and has a low gas permeability can be provided, and the present invention has been completed.

That is, the polymer composition of the present invention comprises a polymer (A) which is a block copolymer of isobutylene and styrene and a polymer (B) which is a bromide of a copolymer of p-methylstyrene and isobutylene. ), Wherein the polymer (A) is in an unvulcanized state and the polymer (B) is in a vulcanized state.

The block copolymer of isobutylene and styrene constituting the polymer composition according to the present invention (hereinafter referred to as “block copolymer”)
It is called polymer (A). ) Has a large vibration damping capacity at room temperature and has no double bond in the main chain.
It is a thermoplastic resin having extremely high heat aging resistance, excellent weather resistance such as ozone resistance and ultraviolet light resistance, and excellent flexibility without blending a softener. In addition, since it has thermoplasticity, injection molding is possible, and since there is no need for a vulcanizing step at the time of molding, it also has a feature of being excellent in productivity.

Further, since the polymer (A) has a characteristic of low gas permeability, it is possible to provide a polymer molded article which highly suppresses the transmission of gas such as oxygen.

On the other hand, the polymer (B), which is a bromide of a copolymer of p-methylstyrene and isobutylene, has a large vibration damping ability in the room temperature region as in the case of the polymer (A), and has a double bond in the main chain. Although it has the characteristic of being excellent in ozone resistance and aging resistance because it has no bond, it is a rubber-like substance and requires a long vulcanization step which takes a long time during molding, and furthermore, it has a thermosetting property. There is a problem that it is impossible to recycle because of having.

However, as in the polymer composition according to the present invention, the polymer (A) and the polymer (B) are mixed, and the polymer (B) in a vulcanized state is further polymerized by dynamic vulcanization. (A) When dispersed in a so-called sea-island structure, it has a large vibration damping capacity in the room temperature range, excellent ozone resistance, aging resistance and flexibility, and low gas permeability. While maintaining the advantage described above, even if it contains the polymer (B), it shows thermoplasticity as a whole. For this reason, injection molding and recycling become possible.

Accordingly, the polymer composition according to the present invention is suitably used in the fields of vibration damping and vibration damping rubber members as a material having both easy processability, recyclability and low gas permeability. .

[0023]

Next, the polymer composition according to the present invention will be described in detail.

[Polymer (A)] The polymer (A) is a block copolymer comprising a segment of polyisobutylene and a segment of polystyrene, and has an extremely high vibration damping ability as described above. . Also,
Since the polymer (A) has thermoplasticity, it can be molded at a temperature equal to or higher than the melting point by injection molding.

In the present invention, the polymer (A) is particularly preferably a styrene-isobutylene-styrene triblock copolymer (SIBS).

The weight ratio of styrene units in the polymer (A) (hereinafter referred to as “styrene content”) is not particularly limited, but is preferably 10 to 4% of the entire polymer (A).
It is preferably 0% by weight. When the styrene content increases, the hardness tends to increase.On the contrary, when the styrene content decreases, the pseudo-crosslinking point decreases and the rubber elasticity tends to decrease.However, when the styrene content is within the above range, the polymer ( A) The flexibility and rubber elasticity are maintained in appropriate ranges. The styrene content of the polymer (A) is preferably from 15 to 35% by weight, more preferably from about 17 to 30% by weight, in the above range.

[Polymer (B)] The polymer (B) is obtained by brominating a copolymer of p-methylstyrene and isobutylene. More specifically, the polymer (B) has a methyl group in the p-methylstyrene unit of the copolymer. The hydrogen in the group is replaced by bromine.

Since the polymer (B) has no double bond, it has extremely excellent weather resistance, ozone resistance and aging resistance. In particular, the ozone resistance is superior to butyl rubber, brominated butyl rubber, chlorinated butyl rubber and the like having the same main structure of isobutylene.

Although the weight ratio of p-methylstyrene in the polymer (B) is not particularly limited, it is preferably 5 to 20% by weight of the whole polymer (B).
More preferably, it is 10 to 10% by weight. When the weight ratio of p-methylstyrene increases, the glass transition point tends to increase and the hardness tends to increase, and when it decreases, the crosslinking point tends to decrease and the crosslinkability tends to decrease. For example, the flexibility, vibration damping ability, crosslinkability and the like of the polymer (B) are maintained in appropriate ranges.

The content ratio of bromine in the polymer (B) (hereinafter referred to as "bromine content") is not particularly limited, but the bromine content of the polymer (B) is 0.1%.
It is preferably from 6 to 2% by weight, more preferably from 1.2 to 2% by weight. As the content of brominated p-methylstyrene increases, the reactivity increases, while the crosslinking density increases and the hardness tends to increase.On the contrary, when the content decreases, the crosslinking does not proceed and the creep increases. There is a tendency, but if the content ratio is within the above range, the polymer
The flexibility and crosslinkability of (B) are maintained in an appropriate range.

Specific examples of the polymer (B) include, for example,
Exxon Chemical Co., Ltd. “EXXPRO 89-
1 "(weight ratio of p-methylstyrene 5% by weight, bromine content 1.2% by weight), trade name" EXXPRO 9 "
0-10 "(p-methylstyrene weight ratio 7.5% by weight, bromine content 2.0% by weight), trade name" EXX "
PRO 89-4 "(weight ratio of p-methylstyrene: 7.5% by weight, bromine content: 1.2% by weight); trade name" EXXPRO 93-5 "(weight ratio of p-methylstyrene: 7.5; Weight%, bromine content 0.7% by weight), trade name “EXXPRO 93-4” (weight ratio of p-methylstyrene 5.0% by weight, bromine content 2.0% by weight) and the like.

[Blending Ratio of Polymer (A) and Polymer (B)] In the polymer composition according to the present invention, the polymer (A)
The mixing ratio of the polymer (A) and the polymer (B) is not particularly limited, but the ratio of the polymer (A) to the total amount of the polymer (A) and the polymer (B) is preferably 30% by weight or more, The proportion of the polymer (B) in the total amount is 30% by weight.
It is preferable that this is the case.

In general, when the blending ratio of the polymer (A) is too large as compared with the polymer (B), the deformation at a high temperature tends to increase, and conversely, the blending ratio of the polymer (B) becomes larger than that of the polymer (A). If the amount is too large, the moldability tends to decrease and recycling tends to be difficult.However, when the mixing ratio satisfies the above range, the deformability at a high temperature, the moldability of the polymer composition, Recyclability is maintained in an appropriate range.

When the mixing ratio satisfies the above range, it is possible to obtain a polymer composition having a good state after dynamic vulcanization and good injection moldability, a small compression set, and a gas composition. A polymer composition capable of providing a polymer molded article having a low permeability can be obtained.

The proportion of the polymer (A) in the total amount of the polymer (A) and the polymer (B) is preferably 35% in the above range.
It is preferably at least 40% by weight, more preferably at least 40% by weight. Polymer (A) and polymer (B)
The ratio of the polymer (B) to the total amount of the above is particularly preferably 35% by weight or more, more preferably 40% by weight or more in the above range.

[Method for Preparing Polymer Composition] As a method for preparing the polymer composition of the present invention, for example, polymer
A method in which a vulcanizing agent or a vulcanization accelerator is blended with a mixture of (A) and the polymer (B), and the mixture is heated while kneading to advance vulcanization (ie, dynamic vulcanization). .

Hereinafter, as a method for producing the polymer composition of the present invention, the above-mentioned method by dynamic vulcanization will be described as a representative.

The vulcanizing agent and vulcanization accelerator for vulcanizing the polymer (B) are not particularly limited, and various conventionally known vulcanizing agents can be used. Combinations are included. In this case, zinc white is used as a vulcanizing agent and the polymer (B) 10
0.01 to 4 parts by weight, preferably 0.1 to 4 parts by weight, per 0 parts by weight.
It is appropriate to add 0.5 to 3 parts by weight. Further, stearic acid is used in an amount of 0.01 to 100 parts by weight of the polymer (B).
It is appropriate to add 4 parts by weight, preferably 0.05 to 2 parts by weight. Instead of the combination of zinc white and stearic acid, zinc stearate may be used, or another vulcanization accelerator may be used in combination with zinc white and stearic acid.

Since the polymer (A) does not have a double bond in the molecule, the polymer (A) is cured by a vulcanizing agent or a vulcanization accelerator for dynamically vulcanizing the polymer (B). The problem of vulcanization does not occur.

The other vulcanization accelerators include, for example, DM
Thiazoles such as (dibenzothiazyl disulfide), M (mercaptobenzothiazole), MZ (zinc salt of mercaptobenzothiazole) and CZ (N-cyclohexyl-2-benzothiazylsulfenamide); TET
Thiurams such as (tetraethylthiuram disulfide), TT (tetramethylthiuram disulfide), TBT (tetrabutylthiuram disulfide), TRA (dipentamethylenethiuram tetrasulfide); PZ (zinc dimethyldithiocarbamate), EZ (zinc diethyldithiocarbamate) ), BZ (zinc dimeble dithiocarbamate), PX (zinc ethylphenyldithiocarbamate) and the like, and one or more of these are used in combination with zinc white and stearic acid.

The amount of the vulcanization accelerator added depends on the amount of the polymer (B).
The amount is suitably 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, per 100 parts by weight.

For the vulcanization of the polymer (B), as described above,
In addition to using zinc white and stearic acid (and a vulcanization accelerator), a resin cross-linking agent such as an alkylphenol-formaldehyde resin, a thermoreactive phenol resin, an alkyl-phenol formaldehyde resin, or a brominated alkylphenol-formaldehyde resin can also be used. . Examples of such a resin cross-linking agent include “SP1045” (a heat-reactive phenol resin) manufactured by Schenecta Chemicals.

In the present invention, a compounding agent for improving the compatibility between the polymer (A) and the polymer (B) (hereinafter referred to as a compounding agent).
"Compatibilizer"). In addition,
Since both polymer (A) and polymer (B) contain isobutylene, their compatibility is extremely high. Therefore, in the present invention, it is basically unnecessary to add a compatibilizer.

In the present invention, the polymer
A vulcanizing agent and a vulcanization accelerator are blended with (A) and the polymer (B), and a compatibilizer is blended if necessary, and further, if necessary, oils, resins, pigments, fillers, A reinforcing agent or the like can be blended.

As the oil, mineral oils such as paraffin oil, naphthenic oil and aroma oil, and synthetic plasticizers such as dioctyl phthalate (DOP) and dioctyl adipate (DOA) can be used. It is preferred to use oil. These oils have the effect of reducing the hardness of the rubber. The blending amount of the oil is not particularly limited.
0 to 100 parts by weight of the total amount of (A) and polymer (B)
It is appropriate to set within the range of 300 parts by weight. If the amount of the oil exceeds the above range, bleed may occur in the rubber.

As the resin, for example, a coumarone-indene resin [for example, a product name “Escron G-90” (softening point of 80 to 100 ° C.) manufactured by Nippon Steel Chemical Co., Ltd .; 120 "(softening points 111 to 130
℃) etc.), phenol / terpene resin [eg, BA
SF Company's product name "Koresin" (melting point 110-1
30 ° C.), a petroleum hydrocarbon resin [for example, “Quinton A100” (trade name, manufactured by Zeon Corporation) (softening point 1
Synthetic polyterpene resin such as "Nisseki Neopolymer 80" (softening point 8
Aromatic resins such as 3 ° C. and a bromine number of 25) manufactured by Exxon Corp. under the trade name “ESCOLETS 1102” (softening point 94 to 106)
C)), aliphatic cyclic hydrocarbon resins such as "Escolets 8180" (softening point: 80 to 92 ° C, bromine number: 50), rosin derivatives (for example, manufactured by San Nopco) Brand name "SN Tack 754"
Etc.], high styrene resin [for example, Nippon Synthetic Rubber Co., Ltd.
Product name “JSR0061” (softening point about 100 ° C)
Etc.] can be used.

The pigment is for coloring the polymer composition of the present invention. The filler is compounded to increase the bulk of the rubber, and has a function of reducing the amount of the polymer (A) or the polymer (B) used, and can also enhance the strength of the rubber.

In the present invention, dynamic vulcanization is carried out by using a polymer
The mixing is performed by mixing the mixture of (A) and the polymer (B) with the other compounding agent exemplified above, kneading the mixture, and heating while applying a shearing force.

For kneading, kneaders, Banbury mixers, and small laboratory kneaders (for example,
A kneading machine such as “Laboplast Mill” manufactured by Toyo Seiki Seisaku-sho, Ltd.) or an extruder such as a twin screw extruder is used. The kneading temperature is
The temperature at which the polymer (A) completely melts is preferred.

When using a kneader such as a kneader, a Banbury or a Labo Plastomill at the time of kneading, the polymer (A) and the polymer (B) are kneaded with stearic acid, and after several minutes, zinc white is added and kneaded. I just need. By doing so, only the polymer (B) can be vulcanized, and the polymer composition consisting of the polymer (B) in the vulcanized state dispersed in the polymer (A) in the unvulcanized state can be obtained. can get.

Instead of the above method, a method in which stearic acid is blended and kneaded for several minutes, then the above-mentioned vulcanization accelerator is blended and further kneaded for several minutes, and then kneaded by adding zinc white May be used.

When an extruder such as a twin screw extruder is used during kneading, the pelletized polymer (A) and polymer (B) are blended with stearic acid, zinc white and, if necessary, a vulcanization accelerator. And then put into an extruder to perform dynamic vulcanization.

The conditions of the dynamic vulcanization are not particularly limited. For example, while heating at a temperature near or above the melting temperature of the polymer (A), usually at a temperature in the range of 150 to 220 ° C., Until vulcanization is completed, a shearing force may be applied to both polymers in the extruder.

The dynamic vulcanizate obtained as described above is
For example, it can be formed into a pellet shape, and can be formed into a desired shape by using a method of forming a normal plastic such as an injection molding machine.

[Usage Field of Polymer Composition] The polymer composition of the present invention can be used in various fields. For example, an outer cover of a seismic isolation bearing structure; a vibration damping member in a refrigerator or a washing machine; a recording / reproducing device such as a CD, an MD and a cassette tape; a recording of a CD-ROM, a DVD, an MO, and a phase change optical disk (PD).・ In addition to dampers (vibration damping members) in playback equipment, cable dampers and / or jackets for cable-stayed bridges and suspension bridges, shock absorbing cushion members for pachinko balls on pachinko machines, and laminated wood flooring for houses It can be used in various applications for attenuating vibrations, such as vibration members, wheel stops, grips for bicycles or motorcycles, mounts for mirrors, and other low temperature to about 70 ° C. temperature ranges.

[0056]

Next, the present invention will be described with reference to examples and comparative examples.

Example 1 (Preparation of polymer composition) Styrene-isobutylene-styrene triblock copolymer (SI) as polymer (A)
BS, styrene content 30%) [Kanebuchi Chemical Industry Co., Ltd.]
50 parts by weight and a bromide of a copolymer of p-methylene and isobutylene as polymer (B) (p-methylstyrene content 5% by weight, bromine content 1.2% by weight) [EXXXO
N company trade name "EXXPRO 89-1"] 50 parts by weight, stearic acid 0.04 part by weight, vulcanization accelerator DM
(Dibenzothiazyl disulfide) 0.2 part by weight,
Dynamic vulcanization was performed while mixing with a small laboratory kneader in which the temperature in the mill was set to 180 ° C.

Two minutes after the start of dynamic vulcanization (start of kneading), 0.2 parts by weight of zinc oxide was added to the above sample. Next, it was confirmed that the torque increased and the peak value was reached, and when the torque began to decrease, a sample of the polymer composition was taken out of the mill.

Further, this sample was subjected to the following characteristic tests and the like.

(Characteristic test) (1) Evaluation of state after dynamic vulcanization The state of the sample (polymer composition) taken out of the mill was visually observed and evaluated according to the following criteria. A: The surface condition was extremely good. ：: The surface condition was generally good although some granular portions were observed. ×: The sample was in a granular and discrete state and was not organized, and could not be provided for subsequent molding.

(2) Injection Moldability The sample (polymer composition) taken out of the mill was pelletized by using a pelletizer, and the pellet was put into an injection molding machine to form a strip sheet. Evaluation was made according to the following criteria. ：: Injection molding was possible, and the flow of the sample during molding was good. Δ: Injection molding was possible, but the flow of the sample at the time of molding was insufficient, so that a part of the sample was poorly filled. X: Injection molding was impossible.

(3) Recyclability The strip-shaped sheet formed by the injection molding in the above (2) is pelletized again and then put into an injection molding machine, whereby it is possible to perform melting, pelletizing and injection molding again. It was confirmed whether or not there was, and the result was evaluated according to the following criteria. ：: Remelting, pelletizing and injection molding were possible, and the recyclability was excellent. ×: Reforming was not possible and could not be recycled.

(4) Oxygen Permeability Coefficient A sample (polymer composition) formed into a pellet by injection molding in the above (2) was molded to prepare a test piece having a thickness of about 0.5 mm.

Using the above test piece, JIS K 7126
According to the method A (differential pressure method) described in "Testing method for gas permeability of plastic films and sheets", the test temperature was 20 to
At 30 ° C., the permeability coefficient of oxygen (cm ³ · cm / cm ² · s ·
cmHg).

(5) Compression set A sample (polymer composition) formed into a pellet by the injection molding in the above (2) was molded to have a thickness of 12.70 ± 0.
A cylindrical test piece having a diameter of 13 mm and a diameter of 29.0 mm was prepared.

Using the above test piece, JIS K 626
2 According to the compression set test method described in “Test Method for Permanent Strain of Vulcanized Rubber”, test temperature 70 ° C., test time 22
The compression set (%) was determined under the conditions of time and a compression ratio of 25%.

The results of the above characteristic tests are shown in Table 1 below.

Examples 2 and 3 The mixing ratio of the polymer (A) and the polymer (B) and the amounts of stearic acid, vulcanization accelerator DM and zinc oxide were changed as shown in Table 1 below. In the same manner as in Example 1, mixing of each component, dynamic vulcanization, and the like were performed to obtain a pellet-shaped sample (polymer composition).

Comparative Example 1 100 parts by weight of only SIBS as the polymer (A) was charged into a small laboratory kneader (described above) and melted at 180 ° C. to form a sheet.

Comparative Example 2 Brominated product of a copolymer of p-methylene and isobutylene as the polymer (B) (trade name “EXXPRO 8”)
9-1 ") 100 parts by weight, stearic acid 1 part by weight,
When 2 parts by weight of the vulcanization accelerator DM and 2 parts by weight of zinc oxide were charged into a small laboratory kneader (described above) and kneaded, the kneaded product could not be injection-molded. For this reason, it was formed into a sheet by extrusion, and subjected to the measurement of the oxygen permeability coefficient and the measurement of the compression set among the above-mentioned characteristic tests.

Comparative Example 3 In place of the polymer (A) (SIBS), a styrene-vinyl isoprene-styrene triblock copolymer (styrene content 20%) [trade name “HYBRAR” manufactured by Kuraray Co., Ltd.]
VS-1 "], stearic acid, vulcanization accelerator D
Except that the amounts of M and zinc oxide added were changed as shown in Table 1 below, mixing of each component, dynamic vulcanization, etc. were performed in the same manner as in Example 1 to obtain a pellet-shaped sample (polymer composition Product).

Comparative Example 4 A hydrogenated styrene-isoprene-styrene triblock copolymer (styrene content 30%) [trade name “SEP” manufactured by Kuraray Co., Ltd.] was used in place of polymer (A) (SIBS).
TON 2002 ”], and the amounts of stearic acid, vulcanization accelerator DM and zinc oxide added were determined in Table 1 below.
The mixing and dynamic vulcanization of each component were carried out in the same manner as in Example 1 except that the sample was changed as shown in Table 1 to obtain a pellet-shaped sample (polymer composition).

Using the samples (or sheet-like molded products) obtained in Examples 2 and 3 and Comparative Examples 1 to 4, the above-described characteristic test was performed.

Table 1 shows the above results.

[0075]

[Table 1]

As is clear from Table 1, all of Examples 1 to 3 were in good condition after dynamic vulcanization, and showed good results in both injection moldability and recyclability.

On the other hand, in Comparative Example 1 using the polymer (A) alone, there was a problem that the compression set was large. In Comparative Example 2 using the polymer (B) alone, injection molding and recycling were difficult. There was a problem that was impossible.

In Comparative Example 3 using a styrene-vinylisoprene-styrene triblock copolymer having a double bond in the molecule instead of the polymer (A), the state after dynamic vulcanization, injection molding Although the results of the properties, recyclability and compression set were good, there was a problem that the ozone resistance was lowered. Furthermore, since a copolymer having a higher gas permeability than the polymer (A) was used without using the polymer (A), low gas permeability could not be realized.

Comparative Example 4 using a styrene-hydrogenated isoprene-styrene triblock copolymer in which the ratio of double bonds remaining without hydrogenation in all the double bonds in isoprene is about 1% to several%. In, because the content of double bonds is small,
Although the aging resistance was basically excellent, the aging resistance and the like when used for a long period of time were inferior to those of the polymer compositions of Examples. Also, for Comparative Example 4,
As in Comparative Example 3, no polymer (A) was contained,
Since a copolymer having a higher gas permeability than (A) was used, low gas permeability could not be realized.

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Claims (2)

[Claims] 1. A polymer (A) which is a block copolymer of isobutylene and styrene, and a polymer (B) which is a bromide of a copolymer of p-methylstyrene and isobutylene. A polymer composition wherein A) is in an unvulcanized state and the polymer (B) is in a vulcanized state. 2. The polymer composition according to claim 1, wherein the polymer (B) is dynamically vulcanized at the time of kneading with the polymer (A).