JPH1180444A - Thermoplastic elastomer composition and stopper for medical container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer compsn. excellent in gas barrier property, mechanical strengths, softness and flowability by dynamically thermally treating a (halogenated) isobutylene-isoprene copolymer rubber, a lowly crystalline propylene polymer and a crystalline α-olefin polymer in the presence of a crosslinker. SOLUTION: 10-90 wt.% (halogenated) isobutylene-isoprene copolymer rubber having an isoprene content of 0.5-15 mol.% and a halogen content of 0.5-4.0 wt.%, 88-1 wt.% lowly crystalline propylene polymer having a density of 0.89 g/cm<3> or lower, pref. 0.85-0.88 g/cm<3> , a melt viscosity (190 deg.C) of 50,000 cP or lower, pref. 100-30,000 cP, and a propylene content of 50 mol.% or higher, pref. 55 mol.% or higher, 88-1 wt.% highly crystalline polymer having a density of 0.89 g/cm<3> or higher and, as required, 1-80 wt.% hydrogenated diene polymer having a degree of hydrogenation of 80% or higher are mixed. A crosslinker is added to the resultant mixture, which is then dynamically crosslinked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition and a stopper for a medical container. More particularly, the invention relates to isobutylene-isoprene copolymer rubber and / or its halide, and a low-crystalline propylene-based rubber. A polymer and a high-crystalline α-olefin polymer, and, if necessary, a dynamically heat-treated hydrogenated diene polymer in the presence of a cross-linking agent, having gas impermeability and mechanical The present invention relates to a thermoplastic elastomer composition which is excellent in strength and elastic recovery and is particularly flexible and highly fluid, and a stopper for a medical container for sealing a mouth of a medical container using the composition.

[0002]

2. Description of the Related Art Conventionally, an olefin-based thermoplastic elastomer composition based on isobutylene-isoprene copolymer rubber (IIR) -polyolefin resin has been obtained by dynamically curing a rubber portion by a known method. By this method, it is possible to obtain an olefin-based thermoplastic elastomer composition having excellent elastic recovery and mechanical strength without impairing the gas impermeability, cold resistance, weather resistance, and chemical resistance of the IIR. is there. The olefin-based thermoplastic elastomer is expected to be applied particularly in a soft field. As a method of softening the thermoplastic elastomer, there is a method of improving the mixing ratio of a rubber component or a method of blending a mineral oil-based softener. However, when the compounding ratio of the rubber component is increased, softening is possible, but in particular, fluidity is deteriorated, and it is difficult to balance material properties and moldability. Further, the method of blending a mineral oil-based softening agent requires a large amount of a softening agent to be blended, causing deterioration in physical properties such as elastic recovery and a problem of elution of the softening agent.

[0003] On the other hand, medical containers used for injections, liquid medicines, and the like are provided with stoppers at their mouths in order to maintain reduced pressure in the inside or to prevent deterioration of the contents of the drug and to shut it off from the outside atmosphere. I have. Conventionally, vulcanized butyl rubber excellent in gas shielding properties and rubber elasticity is generally used as a stopper for such medical containers. However, since stoppers made of vulcanized butyl rubber contain accelerators such as sulfur and vulcanization accelerators of many types, even if they are within the test standards set by the Japanese Pharmacopoeia, their additives are not used. Problems that elute over time, limitations on the amount and type of additives used,
Problems such as complication of the process for hygiene management have arisen. In addition, when the injection needle is inserted into the stopper and pulled out, the resistance between the needle and the material is large, or a part of the material is lost, a so-called coring phenomenon occurs. There is also the problem of doing so. A conventional stopper for a medical container can be obtained by vulcanizing butyl rubber in a mold. However, there are many steps of kneading various chemicals, and there is a problem that the vulcanization of rubber requires a long time and the molding cycle is long, resulting in low productivity.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is excellent in gas impermeability, elastic recovery, and mechanical strength, imparting flexibility and fluidity. It is an object to provide a thermoplastic elastomer composition. In addition, the present invention provides a stopper for a medical container, which does not dissolve additives or the like over time, facilitates insertion of an injection needle, does not cause a coring phenomenon, and is highly gas-tight and airtight. The purpose is to do.

[0005]

The present invention relates to (a) 10 to 90% by weight of an isobutylene-isoprene copolymer rubber and / or a halogenated isobutylene-isoprene copolymer rubber, and (b) a propylene-based low-crystalline polymer ( Below "(b)
88 to 1% by weight) and (c) an α-olefin-based high crystalline polymer (hereinafter referred to as “(c)
88-1 wt% [also referred to as "highly crystalline polymer"]
(A) + (b) + (c) = 100% by weight] is dynamically heat-treated in the presence of (e) a crosslinking agent to provide a thermoplastic elastomer composition. Also, the present invention
(A) Isobutylene-isoprene copolymer rubber and / or halogenated isobutylene-isoprene copolymer rubber 1
0-90% by weight, (b) propylene-based low crystalline polymer 8
8 to 1% by weight, (c) 88 to 1% by weight of an α-olefin-based highly crystalline polymer, and (d) hydrogenated diene-based polymer 1
~ 80% by weight [(B) + (B) + (C) +
(D) = 100% by weight] is dynamically heat-treated in the presence of (e) a crosslinking agent to provide a thermoplastic elastomer composition. Further, the present invention provides a stopper for a medical container, comprising the above thermoplastic elastomer composition.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) used in the thermoplastic elastomer composition of the present invention comprises an isobutylene-isoprene copolymer rubber and / or a halogenated isobutylene-isoprene copolymer rubber. Among them, the isobutylene-isoprene copolymer rubber is an isobutylene / isoprene rubbery amorphous copolymer containing 0.5 to 15 mol%, preferably 0.8 to 5.0 mol% of isoprene. Examples of the halogen in the halogenated isobutylene-isoprene copolymer rubber include chlorine and bromine. The content of the halogen is usually 0.5 to 4.0.
% By weight. These components (a) can be used alone or in combination of two or more.

The component (b) used in the thermoplastic elastomer composition of the present invention is a propylene-based low-crystalline polymer, and is mainly composed of an amorphous or low-crystalline homopolymer of propylene or propylene. Or a low-crystalline copolymer. (B) Examples of the low crystalline polymer include atactic polypropylene, propylene / ethylene copolymer, propylene / 1-butene copolymer, propylene / 1-pentene copolymer, and propylene / 3-methyl-1- Butene copolymer, propylene / 1-
Hexene copolymer, propylene / 3-methyl-1-pentene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 3-ethyl-1-pentene copolymer, propylene / 1-octene copolymer Polymer, propylene / 1-decene copolymer, propylene / 1-undecene copolymer, propylene / 1-butene / ethylene terpolymer, propylene / 1-hexene / 1-octene terpolymer, propylene Amorphous polyolefin polymer having a propylene component as a main component such as / 1-hexene / 4-methyl-1-pentene terpolymer or low-crystalline polyolefin polymer. Polymer or atactic polypropylene low crystalline polymer, propylene / ethylene amorphous copolymer or propylene On / Ethylene low crystalline copolymer and a propylene / 1-butene amorphous copolymer or a propylene / 1-butene low-crystallinity copolymer. In these (b) low-crystalline polymers, the content of the propylene unit is 1 in total of the propylene unit and the α-olefin.
Usually, it is preferably at least 50 mol%, more preferably at least 55 mol%, based on 00 mol%.

[0008] (b) The low crystalline polymer may be a random copolymer or a block copolymer, but it is preferable that the bonding mode of at least the propylene unit is mainly an atactic structure. (B) The low crystalline polymer is an amorphous polymer containing no crystalline component, a low crystalline polymer or an amorphous polymer partially containing a crystalline component. In such a low-crystalline polymer (b), the degree of crystallinity is closely related to the density, and the degree of crystallinity can be generally more simply substituted by the density. That is, in these polymers,
The density must be 0.89 g / cm ³ or less, and particularly preferably 0.85 to 0.88 g / cm ³ . In this case, if the density exceeds 0.89 g / cm ³ , it is not preferable because the obtained composition has insufficient flexibility to achieve the intended flexibility.

The melt viscosity of the component (b) is not particularly limited, but a low viscosity is preferred from the viewpoint of improving the moldability of the composition of the present invention. Specifically, the melt viscosity at 190 ° C. is 50,000 cps or less, preferably 100 to
30,000 cps, particularly preferably 200 to 20,000
00 cps. In the present invention, the low crystalline polymer (b) may be used alone or in combination of two or more.

As the (b) low-crystalline polymer, atactic polypropylene produced as a by-product during the production of crystalline polypropylene may be used, or may be produced from raw materials and used. When producing from a raw material, for example, it can be obtained by polymerizing a raw material monomer in the presence of hydrogen or in the absence of hydrogen using a titanium-supported catalyst supported on magnesium chloride and triethylaluminum. From the viewpoint of the stability of the supply of the raw material and the stability of the quality, it is preferable to use a predetermined low crystalline polymer produced from the raw material.
(B) Low crystalline polymers include, for example, REXTA (REXTA) of the United States.
C), Ube Lexen CAP and Ubetak APA
Commercially available products such as O can be used.

Further, (c) the highly crystalline polymer used in the thermoplastic elastomer composition of the present invention may be a crystalline ethylene or propylene homopolymer or a crystalline copolymer mainly composed of the ethylene or propylene. It is a polymer. (C) As the high crystalline polymer, for example, high density polyethylene, low density polyethylene, ethylene / 1-
Crystalline ethylene polymers such as butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, isotactic polypropylene, propylene / ethylene copolymer, propylene / 1-butene copolymer Coalesce, propylene / 1-pentene copolymer, propylene /
3-methyl-1-butene copolymer, propylene / 1-hexene copolymer, propylene / 3-methyl-1-pentene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 3- Ethyl-1-pentene copolymer, propylene / 1-octene copolymer, propylene /
1-decene copolymer, propylene / 1-undecene copolymer, propylene / 1-butene / ethylene terpolymer, propylene / 1-hexene / 1-octene terpolymer, propylene / 1-hexene / A crystalline polyolefin polymer having an ethylene component or a propylene component as a main component, such as a 4-methyl-1-pentene terpolymer, may be used.

In such a (c) highly crystalline polymer, the degree of crystallinity is closely related to the density similarly to the component (b), and the degree of crystallinity is generally more simply substituted by the density. Can be. Therefore, (c) the high crystalline polymer needs to have a density exceeding 0.89 g / cm ³ . In this case, if the density is 0.89 g / cm ³ or less, it will be insufficient to impart the desired mechanical strength of the obtained composition, which is not preferable.

The low crystalline polymer (b) and the high crystalline polymer (c) can be blended in advance and used. The method of blending is, for example, a method of blending the components (b) and (c) in a reactor or a blend tank during the polymerization of the components, or a single-screw or twin-screw extruder for the (b) and (c) components, or a kneader or a kneader. Blending with a batch mixer such as a Banbury mixer.

[0014] The thermoplastic elastomer composition of the present invention comprises:
Although the above components (a) to (c) are the main components, [(a) to (c)
The composition containing the component (C) as a main component is hereinafter also referred to as “first composition”]. In addition, (d) a hydrogenated diene polymer is further added in addition to the components (A) to (C). [The composition containing the components (a) to (d) as main components is hereinafter also referred to as a “second composition”. (D) The hydrogenated diene-based polymer is obtained by hydrogenating a polymer mainly composed of a conjugated diene, and is, for example, a homopolymer of a conjugated diene, a random copolymer of a conjugated diene and an aromatic vinyl compound, or an aromatic polymer. A block copolymer consisting of a polymer block of an aromatic vinyl compound and a polymer block of a conjugated diene, a block copolymer consisting of a polymer block of an aromatic vinyl compound and a copolymer block of a conjugated diene / aromatic vinyl compound, A block copolymer consisting of a polymer block of a diene and a copolymer block of a conjugated diene / aromatic vinyl compound, and a tapered shape consisting of a polymer block of a conjugated diene and an aromatic vinyl compound and a conjugated diene, in which the aromatic vinyl compound gradually increases. Block copolymer consisting of blocks, random copolymer block of conjugated diene / aromatic vinyl compound and aromatic Tapered block copolymer consisting of a carbonyl compound and a conjugated diene and gradually increasing the aromatic vinyl compound; a multiblock polymer in which the aromatic vinyl compound polymer block and the conjugated diene polymer block are repeated twice or more; Examples include hydrogenated products of diene-based polymers (hereinafter also referred to as “pre-hydrogenated polymer”) such as group-modified products. Particularly, the following (d-1), (d-2) or (d-3) The hydrogenated diene polymers shown are preferred.

Component (d-1): The component (d-1) is obtained by hydrogenating a polymer mainly composed of a random copolymerized portion of a conjugated diene and an aromatic vinyl compound. Here, as the conjugated diene used for the component (d-1), 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-
Methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene and the like can be mentioned, but they can be industrially used, and In order to obtain a hydrogenated diene polymer having excellent physical properties, 1,3-butadiene, isoprene and 1,3-pentadiene are preferred, and 1,3-butadiene and isoprene are particularly preferred. Further, as the aromatic vinyl compound, styrene, α-methylstyrene, p
-Methylstyrene, t-butylstyrene, divinylbenzene, N, N-dimethyl-p-aminoethylstyrene,
N, N-diethyl-p-aminoethylstyrene, vinylpyridine and the like can be mentioned, and styrene and α-methylstyrene are preferable.

The proportion of the random copolymerized portion of the polymer before hydrogenation in the polymer before hydrogenation is preferably at least 50% by weight, more preferably at least 60% by weight. When the proportion of the random copolymer portion is less than 50% by weight, the flexibility is reduced. In the random copolymerized portion, the proportion of the conjugated diene having an unsaturated bond in a side chain with respect to all the conjugated dienes in the random copolymerized portion is preferably 15% or more, more preferably 20% or more. When the proportion of the conjugated diene is less than 15%, the flexibility is not sufficient, which is not preferable. The ratio (weight ratio) of the conjugated diene / aromatic vinyl compound constituting the polymer before hydrogenation is not particularly limited in the present invention, but is preferably from 95/5 to 40 /.
60, more preferably 93/7 to 50/50.

The component (d-1) of the present invention can be obtained by hydrogenating a polymer mainly composed of a random copolymer portion as described above. And a polymer block such as Examples of the polymer block which may be contained in the pre-hydrogenated polymer include an aromatic vinyl compound polymer, a polybutadiene polymer mainly containing 1,4-bonds, and an aromatic vinyl compound comprising an aromatic vinyl compound and a conjugated diene. Examples include a tapered polymer in which the compound gradually increases. When these polymer blocks are present, the physical properties of the component (d-1) are slightly impaired, but the handling properties are improved due to a decrease in the blocking properties of the material, which may be industrially useful. . The proportion of the polymer block in the total molecular chain of the polymer before hydrogenation is not particularly limited, but is preferably 50% by weight or less, more preferably 40% by weight or less.
When the proportion of the polymer block exceeds 50% by weight, the flexibility is greatly reduced.

The pre-hydrogenated polymer may be a polymer in which the molecular chain of the polymer is extended or branched via the residue of the coupling agent by using a coupling agent. As the coupling agent used at this time, for example, diethyl adipate, divinylbenzene, methyldichlorosilane, silicon tetrachloride, butyltrichlorosilicon, tetrachlorotin, butyltrichlorotin, dimethylchlorosilicon, tetrachlorogermanium, 1,2 -Dibromoethane,
Examples include 1,4-chloromethylbenzene, bis (trichlorosilyl) ethane, epoxidized linseed oil, tolylene diisocyanate, and 1,2,4-benzene triisocyanate. In the (d-1) hydrogenated diene polymer of the present invention, the hydrogenation rate of the double bond of the conjugated diene portion in the molecular chain is preferably 80%, more preferably 85% or more, and further preferably 90%. That is all. If it is less than 80%, the weather resistance will be insufficient. Furthermore, the (d-) of the present invention
1) The hydrogenated diene polymer has a number average molecular weight of preferably 50,000 to 700,000, more preferably 50,000 to 600,000, and
If it is less than 10,000, the mechanical strength will be insufficient, while if it exceeds 700,000, the fluidity will be insufficient and the moldability will be insufficient. The component (d-1) is described in, for example, JP-A-3-725.
No. 12 can be obtained by the method disclosed.

Component (d-2): The component (d-2) is a copolymer containing the following blocks (A), (B) and (C) as main components. Here, the aromatic vinyl compound and the conjugated diene used for obtaining the component (d-2) are the same as those used for obtaining the component (d-1). The preferred (A) block that constitutes the hydrogenated diene polymer of the component (d-2) is a polymer block mainly composed of an aromatic vinyl compound, and specifically, a homopolymer of an aromatic vinyl compound, Alternatively, a polymer block in which 80% by weight or more of a conjugated diene portion of a copolymer with a conjugated diene having an aromatic vinyl compound in the (A) block of 90% by weight or more is preferable. When the content of the aromatic vinyl compound in the block (A) is less than 90% by weight, the strength and weather resistance are reduced. The preferred content of the block (A) in the component (d-2) is 5 to 60% by weight, and more preferably 10 to 55% by weight. If it is less than 5% by weight, heat resistance and mechanical strength are poor, while if it exceeds 60% by weight,
Poor processability and flexibility. The preferred number average molecular weight of the block (A) is from 2,000 to 420,000.

The preferred content of the block (B) constituting the (d-2) hydrogenated diene polymer is 30 to 90% by weight, more preferably 35 to 80% by weight. (B)
When the content of the block is less than 30% by weight, the flexibility is reduced, while when it exceeds 90% by weight, the processability and the mechanical strength are reduced. (B) The vinyl bond content of the conjugated diene portion before the hydrogenation contained in the block is preferably from 25 to 95.
%, More preferably 30 to 90%. (B) Among the conjugated diene blocks before the hydrogenation to become blocks, for example, when the conjugated diene is 1,3-butadiene, if the vinyl bond content is less than 25%, a polyethylene chain is generated when hydrogenated, and the rubber If it exceeds 95%, on the other hand, if it exceeds 95%, the glass transition temperature will increase when hydrogenated, and the rubbery properties will be lost, which is not preferable. (B) The block preferably has a number average molecular weight of 15,000 to 63,000, more preferably 35,000 to 420,000, and a conjugated diene weight in which the double bond of the conjugated diene portion is hydrogenated by 80% or more. It is a united block.

Further, the block (C) constituting the block copolymer for obtaining the component (d-2) is a polybutadiene polymer block having a vinyl bond content of less than 25%, preferably less than 20%. If the vinyl bond content is 0% or more, the resinous properties are lost when hydrogenated, and the properties of the thermoplastic elastomer as the block copolymer are lost. The content of the block (C) in the block copolymer is 5 to 60% by weight, preferably 5 to 50% by weight. If the content of the block (C) is less than 5% by weight, the mechanical properties of the component (d-2) are inferior.
(C) The block preferably has a number average molecular weight of 0.250,000 to 420,000, and is a polymer block in which the double bond of the butadiene portion of the polybutadiene block is hydrogenated by 80% or more.

Further, the block copolymer constituting the component (d-2) comprises at least one of the polymer blocks (A), (B) and (C) via a coupling agent residue. It may be a block copolymer in which the polymer molecular chain is extended or branched as shown below, for example, by bonding to a polymer unit composed of a block. [(A)-(B)-(C)] nX [(A)-(B)-(C)] X [(A)-(B)] [wherein n is 2-4 Integer and X represent a coupling agent residue, and the coupling agent used is the same as that used in the component (d-1). ]

The hydrogenation of the above block copolymer saturates the double bond of the conjugated diene portion of the block copolymer, so that the block copolymer is a hydrogenated diene polymer (d-2). The components are obtained. Here, it is necessary that 80% or more of the double bond of the conjugated diene is saturated, preferably 90% or more, and more preferably 95 to 100%. If the saturation ratio of the double bond in the conjugated diene portion is less than 80%, the thermoplastic elastomer composition will have poor thermal stability and durability. The number average molecular weight of the component (d-2) is from 50,000 to 700,000, preferably from 100,000 to 600,000. If it is less than 50,000, heat resistance, strength, fluidity, and processability decrease, while if it exceeds 700,000, fluidity, processability,
Poor flexibility. The component (d-2) is described in, for example,
No. 133406 can be obtained.

Component (d-3): (d-3) The hydrogenated diene polymer is (D) a polybutadiene polymer block having a vinyl bond content of 25% or less (hereinafter referred to as "(D) block").
(E) a conjugated diene polymer block or an aromatic vinyl compound-conjugated diene copolymer block, wherein the vinyl bond content of the conjugated diene portion is 25 to 95.
% Of the polymer block (hereinafter also referred to as “(E) block”) is (D)-(E)-(D) or (D)-
It is obtained by hydrogenating at least 80% of the double bond portion of the linear or branched block copolymer arranged as in (E).

Here, the aromatic vinyl compound and the conjugated diene used for obtaining the component (d-3) include:
The compounds exemplified as those used for obtaining the component (d-1) can be mentioned. The block (D) in the component (d-3) becomes a crystalline polymer block having a structure similar to ordinary low density polyethylene (LDPE) by hydrogenation. (D) The 1,2-vinyl bond content in the block is usually 25% or less, preferably 20% or less, more preferably 15% or less.
(D) If the 1,2-vinyl bond content in the block exceeds 25%, the drop in the crystal melting point after hydrogenation is remarkable, and the mechanical strength is poor.

The (E) block is a conjugated diene polymer block or an aromatic vinyl compound-conjugated diene copolymer block, and a rubbery ethylene-butene-1 copolymer block or an aromatic vinyl A polymer block having a structure similar to that of the compound-ethylene-butene-1 copolymer is obtained.

The amount of the aromatic vinyl compound used in the block (E) is 35% by weight or less, preferably 30% by weight or less of the monomers constituting the block (E).
More preferably, it is 25% by weight or less, and when it exceeds 35% by weight, the glass transition temperature of (E) block increases,
Poor low-temperature properties and flexibility. The vinyl bond content of the conjugated diene portion of the block (E) is 25 to 95%, preferably 25 to 75%, and more preferably 25 to 55%. Thus, for example, when the conjugated diene is 1,3-butadiene,
Each shows a crystal structure derived from a polyethylene chain and a polybutene-1 chain, has resin-like properties, and is inferior in flexibility.

In the block copolymer for obtaining the component (d-3), the ratio of the block (D) to the block (E) is usually 5 to 90% by weight, preferably 10 to 90% by weight of the block (D). 80% by weight, (E) block 95 to 10% by weight, preferably 90 to 20% by weight [provided that (D) +
(E) = 100% by weight]. If the content of the block (D) is less than 5% by weight and the content of the block (E) exceeds 95% by weight, the crystalline polymer block is insufficient, and the mechanical properties of the component (d-3) are not preferable. If the content of the block (D) exceeds 90% by weight and the content of the block (E) is less than 10% by weight, the hardness of the component (d-3) increases, which is not preferable. The (D) block preferably has a number average molecular weight of 0.250,000 to 630,000, and more preferably 10,000 to 4
80,000. Further, the number average molecular weight of the (E) block is preferably from 50,000 to 66.5,000, more preferably from 20,000 to
540,000.

The block copolymer for obtaining the component (d-3) is a polymer comprising at least one polymer block of the block (D) and the block (E) via a coupling agent residue. It may be a block copolymer which is bonded to a united substance and has an extended or branched polymer molecular chain, for example, as represented by the following formula. [(D)-(E)] nx ([D)-(E)-(D)] nx (wherein n and X are the same as above). D-1) The same compounds as those used for the component are exemplified.

The hydrogenation of the above block copolymer saturates the double bond of the conjugated diene portion of the block copolymer, whereby the block copolymer is a hydrogenated diene polymer (d-3). The components are obtained. Here, the double bond of the conjugated diene must be saturated at least 80%, preferably 90% or more, more preferably 9% or more.
5 to 100%. If the saturation ratio of the double bond in the conjugated diene portion is less than 80%, the thermoplastic elastomer composition will have poor thermal stability and durability. The component (d-3) has a number average molecular weight of 50,000 to 700,000, preferably 100,000 to 600,000. If it is less than 50,000, heat resistance, strength, fluidity, and processability decrease, while if it exceeds 700,000, fluidity, processability,
Poor flexibility. The component (d-3) is described in, for example,
It can be obtained by the method disclosed in Japanese Patent No. 1289576.

The hydrogenated diene polymer (d) of the present invention may be a modified hydrogenated diene polymer modified with a functional group. The modified hydrogenated diene polymer is selected from the group consisting of a carboxyl group, an acid anhydride group, a hydroxyl group, an epoxy group, a halogen atom, an amino group, an isocyanate group, a sulfonyl group and a sulfonate group. It contains at least one functional group. As a method of containing this functional group, a conjugated diene or an aromatic vinyl compound containing a functional group is used, and a copolymer is obtained in a state where the functional group of the monomer is protected to obtain a block copolymer, and the polymerization is completed. Later, a method of adding during polymerization by a technique of deprotection, a method of adding a radical polymerizable monomer having a functional group to a hydrogenated block polymer by a known grafting reaction, a monomer containing a functional group In the presence or absence of an organic peroxide or an azo compound, a method of kneading a hydrogenated diene polymer using a kneader, a mixer, an extruder, or the like to add a functional group, and the like. No.

Although any of these methods can be used to efficiently contain a functional group, the above methods (1) to (5) are simple and effective industrially. The amount of the functional group in the modified hydrogenated diene polymer is usually 0.01 to 10 mol%, preferably 0.1 to 8 mol%, based on the molecules constituting the hydrogenated diene polymer. Preferably it is 0.15-5 mol%. Preferred examples of the monomer that adds a functional group to the hydrogenated diene polymer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and hydroxy. Examples include ethylene methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and dimethylaminoethyl methacrylate.

In the thermoplastic elastomer composition of the present invention, the mixing ratio of the components (a) to (c) or the components (a) to (d) is such that the isobutylene-isoprene copolymer rubber (a) is 10 to 90% by weight. %, Preferably 30 to 80% by weight, more preferably 50 to 75% by weight, and (b) 1 to 88% by weight, preferably 2 to 88% by weight of the propylene-based low crystalline polymer.
0-88% by weight, more preferably 30-88% by weight,
(C) 1 to 88% by weight, preferably 1 to 70% by weight, more preferably 1 to 88% by weight of the α-olefin-based highly crystalline polymer.
60% by weight, and if necessary (D) a hydrogenated diene polymer is blended, (D) 1 to 80% by weight, preferably 10 to 40% by weight, more preferably 15 to 30% by weight of the component [However, (a) + (b) + (c) = 100% by weight or (a) + (b) + (c) + (d) = 100
% By weight].

Here, when the component (a) is less than 10% by weight, the rubber elasticity of the obtained composition deteriorates, the rubber elasticity of the stopper for medical containers deteriorates, the sealing property deteriorates, and the gas shielding property decreases. On the other hand, if it exceeds 90% by weight, the moldability of the composition and the stopper for medical containers is insufficient, which is not preferred. In addition, (b) the low crystalline polymer
If the amount is less than 1% by weight, the flexibility and fluidity of the obtained composition and the stopper for medical containers are insufficient, and if it is more than 88% by weight, the heat resistance of the composition and the stopper for medical containers becomes poor. It is not preferable because it runs short. Further, (c) if the content of the highly crystalline polymer is less than 1% by weight, the resulting composition or the stopper for a medical container will have insufficient shape retention, and if it exceeds 88% by weight, the composition will be unfavorable. It is not preferable because the flexibility of the stopper for medical containers and medical containers is insufficient. further,
(D) If the hydrogenated diene polymer is less than 1% by weight, the flexibility of the obtained composition may be reduced, and the stopper of the medical container may have insufficient flexibility to cause coring, On the other hand, if it exceeds 80% by weight, the molding processability of the composition and the stopper for medical containers is insufficient, which is not preferable.

Next, as the crosslinking agent (e) used in the present invention, a crosslinking agent which is usually used for crosslinking an isobutylene-isoprene copolymer rubber can be used. For example, a sulfur, phenolic resin, metal oxide, metal hydroxide, metal chloride, p-quinonedioxime or bismaleimide-based crosslinking agent can be used. inside that,
Preferred (e) crosslinking agents are phenolic resin crosslinking agents, p
When the quinone dioxime derivative and the component (a) are a halogenated isobutylene-isoprene copolymer rubber, a metal oxide or a metal hydroxide is also preferable. Here, the phenolic resin crosslinking agent used in the present invention is a substance represented by the following general formula.

[0036]

Embedded image

Here, n is an integer of 0 to 10, X is a hydroxyl group or a halogen atom, and R is a saturated hydrocarbon group having 1 to 15 carbon atoms. The above materials are described, for example, in US Pat.
As described in 287,440 and 3,709,840, it is generally used as a crosslinking agent for rubber. And this vulcanizing agent is obtained by polycondensation of a substituted phenol and an aldehyde in an alkaline catalyst.

The amount of the phenolic resin crosslinking agent used is as follows:
(A) 0.5 to 15 parts by weight, based on 100 parts by weight of the component,
Preferably it is 1 to 10 parts by weight, more preferably 2 to 8 parts by weight. When the amount of the phenolic resin crosslinking agent used is 0.
When the amount is less than 5 parts by weight, the degree of crosslinking in dynamic crosslinking is low, and the oil resistance and shape recovery properties of the obtained composition are not sufficient. On the other hand, when the amount is more than 15 parts by weight, the flexibility of the obtained composition Is impaired. The phenolic resin crosslinking agent can be used alone, but can also be used in combination with a crosslinking accelerator to adjust the crosslinking speed. As a crosslinking accelerator,
Organic halides such as stannous chloride, ferric chloride metal halide, chlorinated polypropylene, bromide butyl rubber, and chloroprene rubber can be used. It is more preferable to use a metal oxide such as zinc oxide or a dispersant such as stearic acid.

As the p-quinone dioxime derivative, p-benzoquinone dioxime or p-dibenzoylquinone diamide is used. The amount of the crosslinking agent to be used is 0.2 to 100 parts by weight of the component (A).
It is 10 parts by weight, preferably 0.5 to 7 parts by weight, more preferably 0.8 to 3 parts by weight. When the amount of the crosslinking agent used is less than 0.2 parts by weight, the degree of crosslinking in dynamic crosslinking is low, and the oil resistance and shape recovery properties of the obtained composition are not sufficient, while the amount is more than 10 parts by weight. In such a case, the flexibility of the obtained composition is impaired. The above crosslinking agent can be used alone, but can also be used in combination with a crosslinking accelerator to adjust the crosslinking speed. As the crosslinking accelerator, an oxidizing agent such as lead tan or dibenzothiazoyl sulfide can be used. It is more preferable to use a metal oxide such as zinc oxide or a dispersant such as stearic acid.

Further, examples of the metal oxide used for crosslinking include zinc oxide, magnesium oxide, lead oxide, and calcium oxide. In addition, commonly used accelerators are 2,6-di-t-butyl-p-cresol, N, N
-Diethylthiobromine, di-o-tolylguanidine, dipentamethylenethiuram tetrasulfide, ethylene trithiocarbonate, 2-mercapto-benzothiazole, benzothiazole disulfide, N-phenyl-
β-naphthylamine, tetramethylthiuram disulfide, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, and zinc dimethyldithiocarbamate. Preferably, the crosslinking system contains zinc oxide or magnesium oxide.

Further, an organic carboxylate of a metal of a metal oxide used for crosslinking is also preferable. The carboxylic acids used here include, for example, propionic acid, acrylic acid, butyric acid, methacrylic acid, valeric acid, hexanoic acid, octanoic acid, 2-ethylhexanoic acid, decanoic acid, palmitic acid, myristic acid, lauric acid, stearic acid , Oleic acid, naphthenic acid, benzoic acid and the like. The amount of the metal oxide used as a crosslinking agent is 0.2 to 10 parts by weight, preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the component (a).

Further, examples of the metal hydroxide used for crosslinking include zinc hydroxide, magnesium hydroxide, lead hydroxide and calcium hydroxide. The amount of the metal hydroxide used as a cross-linking agent is 0.1 to 100 parts by weight of the component (a).
It is 2 to 10 parts by weight, preferably 0.3 to 5 parts by weight.

The thermoplastic elastomer composition of the present invention comprises:
As described above, the components (a) to (c), or (a) to
(D) The component is the main component.
(F) A softening agent for rubber may be blended (this composition is hereinafter also referred to as “third composition”). As the (f) softener used in the present invention, naphthenic oil or paraffinic mineral oil can be used. By such oil exhibition, processability,
Flexibility is further improved. In this case, the oil extension is (a)
0 to 200 parts by weight, preferably 0 to 100 parts by weight of the composition consisting of the components (c) to (c) or (a) to (d).
To 100 parts by weight, more preferably 0 to 50 parts by weight.

The thermoplastic elastomer composition of the present invention may further comprise the above component (a), component (b), component (c), or, if necessary, in addition to the component (d), Depending on the application, mechanical strength, flexibility, antioxidant, antistatic agent, weathering agent, ultraviolet absorber, lubricant, antiblocking agent, sealability improver, crystal nucleating agent, in an amount not to impair the moldability, Flame retardants, antibacterial and antifungal agents, tackifiers, plasticizers, coloring agents such as titanium oxide and carbon black, glass fibers, carbon fibers, metal fibers, aramid fibers,
Glass beads, asbestos, mica, calcium carbonate,
Potassium titanate whisker, talc, barium sulfate,
Fillers such as glass flakes, fluororesins, etc.
A rubbery polymer, a thermoplastic resin, and the like other than the components (d) to (d) can be appropriately compounded.

The thermoplastic elastomer composition of the present invention comprises:
It is manufactured by the method exemplified below, but is not limited unless it exceeds the gist of the present invention. Production method 1 (first composition or third composition ) The three components (a), (b), and (c) are converted into (b), (c)
Is kneaded at a temperature (usually 120 ° C. to 200 ° C.) at which the components are melted until the components are uniformly mixed. (E) A crosslinking agent and, if necessary, a crosslinking aid are added, and the temperature is set or raised to a temperature at which a crosslinking reaction occurs, and heat treatment is performed dynamically. The component (f) of the third composition, the above-mentioned various additives, rubber-like substances, and the like may be added during the step and after the completion of all the steps. Production method 2 (first composition or third composition ) A mixture of components (b) and (c) blended in a reactor, or prepared by an extruder or batch type mixer (b) and (b) C) preparing a mixture of the components; The above mixture and the component (A) are kneaded at a temperature at which the mixture melts (usually 120 ° C to 200 ° C) until the components are uniformly mixed. (E) A crosslinking agent and, if necessary, a crosslinking aid are added, and the temperature is set or raised to a temperature at which a crosslinking reaction occurs, and heat treatment is performed dynamically. The component (f) of the third composition, the above-mentioned various additives, rubber-like substances, and the like may be added during the step and after the completion of all the steps.

Production method 3 (second composition or third composition)
Thing ) (a), (b), (c) and (d)
Kneading is carried out at a temperature at which the components (b), (c) and (d) melt (usually 120 ° C. to 200 ° C.) until the components are uniformly mixed. (E) A crosslinking agent and, if necessary, a crosslinking aid are added, and the temperature is set or raised to a temperature at which a crosslinking reaction occurs, and heat treatment is performed dynamically. The component (f) of the third composition, the above-mentioned various additives, rubber-like substances, and the like may be added during the step and after the completion of all the steps. Production method 4 (second composition or third composition ) The three components (a), (b) and (c) are melted at a temperature at which the components (b) and (c) melt (usually from 120 ° C to 20 ° C).
(0 ° C) until the components are uniformly mixed. (E) A crosslinking agent and, if necessary, a crosslinking aid are added, and the temperature is set or raised to a temperature at which a crosslinking reaction occurs, and heat treatment is performed dynamically. Furthermore, heat treatment is performed dynamically by adding the component (d). The component (f) of the third composition, the above-mentioned various additives, rubber-like substances, and the like may be added during the step and after the completion of all the steps.

Production method 5 (second composition or third composition)
Things) were blended in reactor (B) and (C) a mixture of components, or in an extruder or a batch mixer of (ii)
And a mixture of (c) components is prepared. The above mixture and the components (a) and (d) are melted at a temperature at which the mixture and the component (d) are melted (usually 120 ° C to 2 ° C).
(00 ° C.) until the components are uniformly mixed. (E) A crosslinking agent and, if necessary, a crosslinking aid are added, and the temperature is set or raised to a temperature at which a crosslinking reaction occurs, and heat treatment is performed dynamically. The component (f) of the third composition, the above-mentioned various additives, rubber-like substances, and the like may be added during the step and after the completion of all the steps. Production method 6 (second composition or third composition ) A mixture of components (b) and (c) blended in a reactor, or an extruder or a batch type mixer (b)
And a mixture of (c) components is prepared. The above mixture and the component (a) are kneaded at a temperature at which the mixture is melted (usually 120 ° C to 200 ° C) until the components are uniformly mixed. (E) A crosslinking agent and, if necessary, a crosslinking aid are added, and the temperature is set or raised to a temperature at which a crosslinking reaction occurs, and heat treatment is performed dynamically. Furthermore, heat treatment is performed dynamically by adding the component (d). The component (f) of the third composition, the above-mentioned various additives, rubber-like substances, and the like may be added during the step and after the completion of all the steps.

As a method for producing the thermoplastic elastomer composition of the present invention, any of Production Methods 1 to 6 is preferred. Examples of the apparatus for producing the thermoplastic elastomer composition of the present invention include roll mills, Banbury mixers, and closed kneaders such as pressure kneaders, or single-screw extruders, twin-screw extruders, and the like, which are usually used in the rubber and resin industries. Is used as long as the above-described production method can be applied, and is not particularly limited.

The thermoplastic elastomer composition of the present invention comprises:
Medical containers, plugs and gaskets of the containers, and medical transportation using conventional vulcanized rubber, taking advantage of its excellent gas shielding properties, flexibility, moldability, and elastic recovery. It can be used as a vibration damping material for industrial goods such as pipes, automobiles, light electrical equipment and audio equipment.

The thermoplastic elastomer compositions (first to third compositions) of the present invention are particularly useful for stoppers for medical containers. The stopper for a medical container of the present invention is preferably formed by injection-molding the thermoplastic elastomer composition at 170 to 270 ° C. The hardness of the thermoplastic elastomer composition used for the stopper for medical containers of the present invention is not particularly limited. However, for applications requiring needle insertion, such as lyophilized preparations and vacuum blood collection tubes, the hardness is 30 to JIS-A hardness. Preferably it is 60. If the hardness is less than 30, the heat resistance is insufficient, and the hardness is 60.
If it exceeds, coring is undesirably generated.
The stopper for a medical container of the present invention, by using the thermoplastic elastomer composition of the present invention, there is no elution of additives and the like over time, easy insertion of the injection needle, no occurrence of coring phenomenon, Rich in gas shielding and airtightness, and easy to mold.

[0051]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In the examples, parts and% are based on weight unless otherwise specified.
Various measurements in the examples were performed by the following methods.

Vinyl bond content (1,2-bond content) Calculated by the Hampton method using infrared analysis. It was determined by infrared analysis based on the absorption of a phenyl group having a bound styrene content of 679 cm ^-1 . Number-average molecular weight The number-average molecular weight is determined by using trichlorobenzene as a solvent.
It was determined in terms of polystyrene using gel permeation chromatography (GPC) at 35 ° C.

JIS A hardness Measured according to JIS K6301. Tensile strength and maximum elongation Measured according to JIS K6301. Elastic recovery The compression set was used as an index of elastic recovery. The measurement condition is a condition of 25 ° C. × 22 hours and 25% compression. The smaller the compression set, the better the elastic recovery. The fluidity MFR was measured under the following conditions. Temperature: 230 ° C Load: 10kg

Medical hygiene The measurement was carried out according to the Japanese Pharmacopoeia, 13th edition, Rubber Transfusion Plug Test Method. The generation of rubber dust at the time of inserting or removing the needle (18G) into the coring 2 mm sheet was measured. The moldable cylinder was injection molded, and the molding shrinkage in the injection direction and the direction perpendicular to the injection direction was determined. The heat- shrinkage rate when the heat-resistant injection-molded cylinder was subjected to steam sterilization at 120 ° C. for 60 minutes was determined. As a film having a gas shielding property of 200 μm, the gas permeability of oxygen was measured.

The polymers used in Examples and Comparative Examples were
These are: IIR isobutylene-isoprene copolymer rubber [Butyl 268 manufactured by Nippon Synthetic Rubber Co., Ltd.] CIIR chlorinated isobutylene-isoprene copolymer rubber [Chloro Butyl 1068 manufactured by Nippon Synthetic Rubber Co., Ltd.] BIIR brominated isobutylene-isoprene copolymer rubber [ Buromo Butyl 2244, manufactured by Japan Synthetic Rubber Co., Ltd.]

AP1 propylene / ethylene amorphous polymer (density: 0.86 g)
/ Cm ³ , melt viscosity: 8,500 cps) [UBETAC UT2385, manufactured by Ube Lexen Co.] AP2 propylene / 1-butene amorphous polymer (density: 0.87
g / cm ³ , melt viscosity: 8,000 cps) [UBETAC UT2780, manufactured by Ube Lexen Co.] AP3 propylene amorphous polymer (density: 0.86 g / cm ³ ,
Melt viscosity: 8,000 cps) [Ube Lexen, U
BETAC UT2180]

PP1 propylene-ethylene block polymer [manufactured by Nippon Polychem Co., Ltd., BC03GS] PP2 propylene-ethylene random polymer [manufactured by Nippon Polychem Co., Ltd., EX6]] PP3 propylene-ethylene random polymer [manufactured by Mitsubishi Chemical Corporation; SPX9430] PP4 polypropylene [ MA03, manufactured by Nippon Polychem Co., Ltd.]

[0058] hydrogenated diene polymer A hydrogenated diene polymer A is a double bond butadiene unit of the random copolymer of styrene and 1,3-butadiene is obtained by hydrogenating the total bound styrene content Is a hydrogenated random copolymer having a vinyl bond content (1,2-bond content) of 80%, a hydrogenation rate of 99%, and a total number average molecular weight of 300,000, before hydrogenation. Hydrogenated diene polymer B Hydrogenated diene polymer B is manufactured by Nippon Synthetic Rubber Co., Ltd. and has an ABC structure (A is a polystyrene block, B is
Is polybutadiene having a large 1,2-bond content, and C is 1,2
-Polybutadiene with low vinyl bond content, B and C are hydrogenated double bonds of the polybutadiene portion)
Having a 1,2-bond content of 39% in part B and 1,2 in part C
2. A hydrogenated block copolymer having a bond content of 15%, a hydrogenation rate of 99%, and a total number average molecular weight of 150,000. Hydrogenated Diene Polymer C Hydrogenated diene polymer C is manufactured by Japan Synthetic Rubber Co., Ltd. and has a DED structure (D is polybutadiene having a small 1,2-bond content, E is 1,2 Polybutadiene with a high bond content, the double bonds of each butadiene moiety being hydrogenated) and the 1,2-bond content of the D moiety being 15
%, The 1,2-bond content of E part is 80%, and the hydrogenation rate is 9%.
A hydrogenated block copolymer having 9% and a total number average molecular weight of 300,000.

Hydrogenated Diene Polymer D Hydrogenated diene polymer D is manufactured by Japan Synthetic Rubber Co., Ltd. and has a DED structure (D is polybutadiene having a small 1,2-bond content, E is A polybutadiene having a high 1,2-bond content, in which the double bond of each butadiene portion is hydrogenated), and the vinyl bond content of the D part is 15%,
Part E has a vinyl bond content of 35% and a hydrogenation rate of 99%
A hydrogenated block copolymer having a total molecular weight of 280,000.

SEBS1 hydrogenated styrene-butadiene-styrene block polymer [Krayton G1657 manufactured by Shell Co., Ltd.] SEBS2 hydrogenated styrene-butadiene-styrene block polymer [ SEPS1 hydrogenated styrene-isoprene-styrene block polymer [Kuraray Co., Ltd. SEPTON 2005] SEPS2 hydrogenated styrene-isoprene-styrene block polymer [Kuraray Co., Ltd., Hibler HVS-3]

Mineral oil softener 1 Paraffin softener [PW-9, manufactured by Idemitsu Kosan Co., Ltd.]
0] Mineral oil softener 2 Paraffin softener [PW-38, manufactured by Idemitsu Kosan Co., Ltd.]
0] Crosslinking agent 1 Brominated alkylphenol formaldehyde [Takkirol 250-1 manufactured by Taoka Chemical Co., Ltd.] Crosslinking agent 2 Alkylphenol formaldehyde [Takkilol 201 manufactured by Taoka Chemical Co., Ltd.] Crosslinking agent 3 p, p'-dibenzoyl Quinone dioxime [Ouchi Shinko Chemical Industry Co., Ltd., Barnock DGM]

Additive 1 Tetrachlorobenzoquinone [Actor CL manufactured by Kawaguchi Chemical Co., Ltd.] Additive 2 Zinc diethylthiocarbamate [Noxeller EZ manufactured by Ouchi Shinko Chemical Co., Ltd.] Additive 3 Zinc stearate [Sakai Chemical Co., Ltd.] additive 4 stearic acid [Kao Co., Ltd., Lunac S30] additive 5 zinc oxide [Sakai Chemical Co., Ltd., Zinhua No. 1]

Examples 1 to 40 and Comparative Examples 1 to 8 (Preparation of Thermoplastic Elastomer Composition) Compositions were prepared according to the following procedures according to the formulation shown in Tables 1 to 6. Preparation method 1 In a pressurized high-temperature kneader (Moriyama Seisakusho, 3000 cc capacity) preheated to 160 ° C, isobutylene-isoprene copolymer rubber and / or halogenated isobutylene-isoprene copolymer rubber, low crystalline polymer Add a high crystalline polymer, a mixture of a low crystalline polymer and a high crystalline polymer, an essential polymer such as a hydrogenated diene polymer, and, if necessary, a mineral oil-based softener, and rotate the rotor for 2 minutes. 1/2
After preliminarily kneading in the lowered state, the temperature inside the kneader becomes 155 ° C., and after each polymer component is melted,
Add a crosslinking agent and, if necessary, a crosslinking aid,
Heat treatment was performed dynamically for 2 seconds to obtain a composition. Further, pellets were produced using a feeder ruder (manufactured by Moriyama Seisakusho).

Preparation Method 2 In a pressurized high-temperature kneader (Moriyama Seisakusho, 3000 cc capacity) preheated to 160 ° C., isobutylene-isoprene copolymer rubber and / or halogenated isobutylene-isoprene copolymer rubber, low crystal Polymers, high-crystalline polymers, essential polymers such as a mixture of low-crystalline and high-crystalline polymers and, if necessary, a mineral oil-based softener are added, and the rotor is halved for 2 minutes. After preliminarily kneading in a lowered state, after the temperature inside the kneader reaches 155 ° C. and each polymer component is melted, a crosslinking agent and a crosslinking assistant are added as needed, and heat treatment is performed dynamically for 4,800 seconds. While obtaining the composition, feeder ruder [Ltd.
Moriyama Seisakusho] was used to produce pellets. Further, using a single-screw extruder (manufactured by Tanabe Plastics Co., Ltd.) having a cylinder diameter of 40 mm, the composition obtained by the above operation and the hydrogenated diene polymer were melt-blended to obtain a target composition.

Further, a method for preparing a blend of a low crystalline polymer and a high crystalline polymer is shown below as Preparation Method 3 and Preparation Method 4. Preparation method 3 A predetermined amount of a low crystalline polymer and a high crystalline polymer are charged into a pressurized high temperature kneader (manufactured by Moriyama Seisakusho, 10 liter capacity) preheated to 160 ° C., and the high crystalline polymer is melted. After that, the mixture was mixed for 300 seconds, discharged, and pellets were produced using a feeder ruder (manufactured by Moriyama Seisakusho). Preparation method 4 First, the low-crystalline polymer was crushed to a size of 2 cm square or less, and the crushed low-crystalline polymer and the high-crystalline polymer were biaxially extruded using a twin screw extruder [PCM45, manufactured by Ikegai Iron Works Co., Ltd. ) To produce pellets.

The evaluation method is as described below.
For evaluation of hardness JIS A, permanent elongation and tensile strength, a pellet having a thickness of 2 mm was prepared from the pellets obtained by the above-mentioned production method using an injection molding machine and subjected to a test. For evaluation of the compression set, a test piece having a thickness of 2 mm produced by the above-mentioned injection molding machine was used, punched, adjusted to a prescribed size by stacking, and subjected to a test. The results are shown in Tables 1 to 6.

As is clear from the comparison between Examples 1 to 40 and Comparative Examples 1 to 8, the composition of the present invention is excellent in the following points. The thermoplastic elastomer composition of the present invention exhibits a soft property without impairing mechanical strength, has excellent elastic recovery, and also has good fluidity required for molding. In addition, since a small amount of the softening agent is required, there is no problem of bleed-out of these components. Also, as for the test items as medical plugs, the balance between mechanical strength, elastic recovery and moldability is excellent, so that the sealing property, medical hygiene property and gas shielding property of the medicine are sufficient.
Furthermore, it has excellent fluidity, has little residual distortion during injection molding, and has small molding shrinkage and heat shrinkage during heat treatment.

On the other hand, Comparative Examples 1 to 8 do not contain the component (ii). Compared with Examples 1 to 40, Comparative Examples 1, 3, 7, and 8 are considered to be equivalent in elastic recovery and mechanical strength, but are not preferred because they lack flexibility and flowability is significantly poor. Further, Comparative Examples 2 and 6
Although it is considered that the elastic recovery property and the flexibility are equivalent to those of the above-described examples, the fluidity is largely inferior and is not preferable. Therefore, the residual strain during injection molding is large, and the molding shrinkage and the heat shrinkage during heat treatment are large, so that it is difficult to use it as a medical plug. Furthermore, Comparative Example 5 has an excellent balance between elastic recovery, flexibility, and fluidity, but contains a large amount of a mineral oil-based softener instead of the component (B).
Since it is inferior in medical hygiene and gas shielding properties, it is also difficult to use this as a medical plug.

[0069]

[Table 1]

[0070]

[Table 2]

[0071]

[Table 3]

[0072]

[Table 4]

[0073]

[Table 5]

[0074]

[Table 6]

[0075]

The thermoplastic elastomer composition of the present invention is excellent in gas shielding properties, flexibility, moldability, and elastic recovery. Therefore, the thermoplastic elastomer composition of the present invention, a conventional vulcanized rubber is used, a medical container,
It can be used as a plug and gasket of the container, a transport pipe for medical use, a vibration damping material for industrial goods such as automobiles, light electric equipment and audio equipment, and the like.

In particular, when the thermoplastic elastomer composition of the present invention is used for a stopper for medical containers, the stopper for medical containers exhibits rubber-like elasticity, so that the sealing property of the container can be maintained for a long time. Is possible. Also, the amount of additives for producing the material is small, and the amount of the softener is small. Therefore, they are superior to conventional vulcanized rubber stoppers in terms of safety for living bodies and accurate analysis of the contents. Further, the stopper for a medical container of the present invention is excellent in gas shielding properties, so that it can be stored for a long time without altering the contents. Further, the stopper for a medical container of the present invention can be favorably molded by an injection molding machine, and productivity can be remarkably improved as compared with a conventional vulcanized rubber. In addition, since it is a thermoplastic material, it is possible to reuse sprues and runners.

Claims (3)

[Claims] (1) 10 to 90% by weight of an isobutylene-isoprene copolymer rubber and / or a halogenated isobutylene-isoprene copolymer rubber, (b) 88 to 1% by weight of a propylene-based low crystalline polymer, and (C) ) 88 to 1% by weight of an α-olefin-based highly crystalline polymer [however,
(B) + (b) + (c) = 100% by weight], and (e) a dynamic heat treatment in the presence of a crosslinking agent. 2. A) isobutylene-isoprene copolymer rubber and / or halogenated isobutylene-isoprene copolymer rubber: 10 to 90% by weight, (b) propylene-based low crystalline polymer: 88 to 1% by weight, (c) 88 to 1% by weight of an α-olefin-based highly crystalline polymer, and (d) 1 to 80% by weight of a hydrogenated diene-based polymer [provided that (a) + (b)
+ (C) + (d) = 100% by weight] is dynamically heat-treated in the presence of (e) a crosslinking agent. 3. A stopper for a medical container, comprising the thermoplastic elastomer composition according to claim 1 or 2.