JPH07275345A - Medical plug body with excellent heat resistance and restoration - Google Patents

Abstract

PURPOSE:To provide a medical plug with heat resistance and restoration in an equal level to vulcanized rubber, by molding a thermoplastic elastomer partially cross-linked with a specific mixture under existence of an organic peroxide. CONSTITUTION:A medical plug is obtained by molding thermoplastic elastomer partially cross-linked with a mixture as described below under existence of organic peroxide: the mixture consisting of 100 parts by weight of hydrogenated block copolymer with number average molecular weight of 5000-250000 obtained by hydrogenating a block copolymer consisting of polymer blocks with main components of vinyl aromatic compound and conjugate diene compound respectively, 20-150 parts by weight of polyphenylene ether resin of homopolymer or copolymer with reduced viscosity (0.5g/dl chloroform solution, measured at 30 deg.C) in arrange of 0.15-0.70 consisting of bonding unit of the equation, 50-300 parts by weight of non-aromatic rubber softener, 5-100 parts by weight of polyolefin hydrocarbon resin. R1-R4 is elected from a group of hydrogen, etc., and they are allowed to be identical or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is highly flexible and has a sealing property upon needle stick, a self-closing property of a hole after needle removal, a permanent elongation, a rubber elasticity, a compression set at a high temperature, a mechanical strength and safety. The present invention relates to a medical plug having excellent hygiene and thermoplasticity.

[0002]

2. Description of the Related Art Conventionally, medical plugs have been prepared by masticating vulcanized rubber such as natural rubber, isoprene rubber, butadiene rubber, butyl rubber or blends thereof, and adding various fillers, reinforcing agents and oils. , Sulfur, vulcanization accelerator, and other auxiliaries are added and kneaded, and the mixture is supplied to the mold of the plug body, heated,
It was obtained by pressurization.

As described above, the conventional plug body requires complicated equipment because complicated steps are required to obtain a molded body, and since many kinds of additives are complicated to adjust, the cost is high and the productivity is high. It was bad. Especially the vulcanization process with a press die,
Since the vulcanization time is about 10 to 20 minutes, it takes a long time,
Inevitably it limited productivity. In addition to this, the plug obtained by the vulcanization method is a manufacturing method with many unnecessary burrs and a deburring process. It was Further, since the stopper obtained by this method is added with sulfur, a vulcanization accelerator, etc. during production, when the stopper comes into contact with the chemical liquid in the container to which the stopper is attached, these additives are added to the chemical liquid. Could be eluted. Furthermore, when this plug is used and then burned in a disposal process, a toxic gas such as sulfurous acid gas is generated, which is not preferable.

For this reason, in recent years, some proposals have been made for the purpose of improving the productivity and safety and hygiene of the thermoplastic elastomer as a raw material, and further making the recyclable stopper. . For example, JP-A-58
-58057, JP-A-59-28965,
Japanese Unexamined Patent Publication (Kokai) No. 61-64253 discloses a plug obtained by mixing a butyl rubber and a thermoplastic elastomer such as polyester, styrene, or olefin, and Japanese Unexamined Patent Publication No. 61-131746 discloses. A plug body made of a styrene thermoplastic elastomer is disclosed. Further, Japanese Patent Laid-Open No. 3-68363 discloses a resin composition for a plug body, which comprises an olefin resin and a hydrogenated block copolymer. Further, Japanese Utility Model Laid-Open No. 61-24050 discloses a plug body made of a thermoplastic elastomer having a hydrogenated block copolymer as a basic raw material.
No. 1 discloses a plug body in which a core material of vulcanized rubber is coated with a thermoplastic elastomer material.

However, the plugs made of these thermoplastic elastomer materials have low heat resistance, are incorporated into a container at the time of sterilization, and are subjected to external stress to some extent, and the temperature is 100 ° C.
When exposed to the above high temperature, problems such as deterioration of physical performance or deformation occur. Most of the needles for which these plugs are used are metal needles with a small diameter of about 1 mmφ, and when a large-diameter resin needle used for infusion is inserted, the needle is removed. After that, the problem that the liquid leaks occurs. Further, as a means for improving it, a plug body in which a vulcanized rubber plug body is covered with plastic, and a plug body formed by covering a vulcanized rubber core material with a thermoplastic elastomer have been proposed. However, it is not perfect, and there is a problem that productivity is poor as in the case of the plug body made only of vulcanized rubber.

[0006] On the other hand, the applicant of the present invention is disclosed in Japanese Patent Laid-Open No. 63-57663.
In the publication, a composition related to the composition of the present invention was applied as a gasket for a syringe, but as a result of further diligent study, the present composition suitable for the purpose of the present invention was found out.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the problems of productivity, hygiene, etc. of a plug obtained by a conventional vulcanization method, and further has flexibility, heat resistance and self-closing after needle removal. It is an object to provide a plug having the same level of heat resistance and recovery characteristics as a plug of a vulcanized rubber material by partially crosslinking a compound of a thermoplastic elastomer having excellent properties.

[0008]

That is, the present invention is
(A) Obtained by hydrogenating a block copolymer composed of a polymer block A containing at least two vinyl aromatic compounds as a main component and a polymer block B containing at least one conjugated diene compound as a main component. Number average molecular weight is 50,
000-250,000 hydrogenated block copolymer 100
In parts by weight, (b) the bonding unit is the following formula (1)

[0009]

[Chemical 2]

(Wherein R1, R2, R3, and R4 are each selected from the group consisting of hydrogen, halogen, hydrocarbon, and substituted hydrocarbon group, and may be the same or different from each other). 20-150 parts by weight of a polyphenylene ether resin which is a homopolymer and / or a copolymer having a reduced viscosity (0.5 g / dl chloroform solution, measured at 30 ° C.) of 0.15 to 0.70, (c) A thermoplastic elastomer is formed by partially cross-linking a compound containing 50 to 300 parts by weight of a non-aromatic softening agent for rubber and (d) 5 to 100 parts by weight of a polyolefin hydrocarbon resin in the presence of an organic peroxide. It is a medical stopper.

The present invention will be described in detail below. The hydrogenated block copolymer used as the component (a) in the present invention is
It is obtained by hydrogenating a block copolymer comprising at least two vinyl aromatic compound-based polymer blocks A and at least one conjugated diene compound-based polymer block B. General formula, A (B-
A) n, B (AB) n, (AB) n, (AB) m
A compound represented by X (wherein n is an integer of 1 to 10, m is an integer of 3 to 8 and X is a polyfunctional residue having m bonds) is suitable and has a single structure. And a mixture of those having different structures, different hydrogenation rates, and the like. As used herein, the expression "mainly composed" means that at least 50% by weight, preferably 70% by weight or more, of the corresponding monomer is occupied. The proportion of the vinyl aromatic compound A constituting the hydrogenated block copolymer is 20 to 40% by weight, preferably 25 to 35% by weight. Further, in these hydrogenated block copolymers, the polymer block A mainly composed of a vinyl aromatic compound and the polymer block B mainly composed of a conjugated diene compound or a hydrogenated product thereof are the same as those of the respective hydrogenated block polymers. The distribution of the conjugated diene compound or its hydrogenated product and vinyl aromatic compound in the molecular chain in the block is random, tapered (in which the monomer component increases or decreases along the molecular chain), partially block-shaped or these In the case where there are two or more polymer blocks A containing the vinyl aromatic compound as a main component and polymer blocks B containing the conjugated diene compound or a hydrogenated product thereof as the main component, each of them may be an arbitrary combination. The polymer blocks may have the same structure or different structures.

Examples of the vinyl aromatic compound constituting the hydrogenated block copolymer of the present invention include styrene and α-
One or two or more types can be selected from methylstyrene, vinyltoluene, p-tert-butylstyrene and the like, and among them, styrene is preferable. Further, as the conjugated diene compound, for example, one kind or two or more kinds can be selected from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3 butadiene and the like, and among them, butadiene, isoprene and these Combinations are preferred. The polymer block B mainly composed of a conjugated diene compound or a hydrogenated product thereof can have a microstructure in the block arbitrarily selected. For example, in the case of a polybutadiene block before hydrogenation, a 1,2-vinyl bond is used. The structure is 25 to 55% by weight, preferably 30 to 50% by weight.

The number average molecular weight of the hydrogenated block copolymer having the above structure is 50,000 to 250,000.
00, preferably 70,000 to 210,000, more preferably 90,000 to 170,000, and the molecular weight distribution (the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / Mn). )) Is 10 or less, preferably 5 or less, and more preferably 2 or less. The hydrogenated block copolymer having a number average molecular weight of less than 50,000 is not preferable because the heat resistance of the obtained plug is lowered. The number average molecular weight of the hydrogenated block copolymer is 25
If it exceeds 50,000, the processability and the permanent elongation property are deteriorated, and the performance of the obtained plug is deteriorated, which is not preferable.

These hydrogenated block copolymers are not limited as long as they have the above-mentioned structure, and the production method thereof is not limited. For example, according to the method described in Japanese Patent Publication No. 40-23798, a lithium catalyst is used. Can be used to synthesize a vinyl aromatic compound-conjugated diene compound block copolymer in an inert solvent. Further, as a method for producing a hydrogenated block copolymer exhibiting more preferable performance, that is, a vinyl aromatic compound-hydrogenated conjugated diene compound block copolymer, for example, JP-B-42-8
The method described in JP-B No. 704 and JP-B No. 43-6636 may be used. However, especially in applications requiring high weather resistance and heat aging resistance, use of a titanium-based hydrogenation catalyst is recommended. Methods disclosed in JP-A-59-133203 and JP-A-60-79005 can be mentioned. At that time, at least 80% or more, preferably 90% or more, of the aliphatic double bond derived from the conjugated diene compound is preferably hydrogenated, and most of the conjugated diene compound is morphologically converted to an olefinic compound. It was done. For example, a butadiene polymer block converts to an ethylene-butylene based polymer block.

Further, a vinyl aromatic compound copolymerized with a polymer block A mainly containing a vinyl aromatic compound and, if necessary, a polymer block B mainly containing a conjugated diene compound or a hydrogenated product thereof. There is no particular limitation on the hydrogenation rate of the aromatic double bond derived from
0% or less is preferable. The hydrogenation rate of the hydrogenated block copolymer can be easily known by infrared spectroscopic analysis or nuclear magnetic resonance analysis.

Next, the polyphenylene ether resin used as the component (b) of the present invention is an essential component for improving the compression set and permanent set strain of the obtained plug, and the bonding unit is represented by the following formula (1).

[0017]

[Chemical 3]

(Wherein R1, R2, R3, and R4 are each selected from the group consisting of hydrogen, halogen, hydrocarbons, and substituted hydrocarbon groups, and may be the same or different from each other). Those having a reduced viscosity (0.5 g / dl chloroform solution, measured at 30 ° C.) in the range of 0.15 to 0.70, preferably 0.20 to 0.60 are used. As this polyphenylene ether resin, a known one can be used. Specific examples include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6ethyl-1,4-phenylene ether), poly (2,6-diphenyl-1,4). -Phenylene ether), poly (2-methyl-6-phenyl-1,4-phenylene ether), poly (2,6-dichloro-1,4-)
Phenylene ether) and the like, and also 2,6-dimethylphenol and other phenols (eg 2,3,3).
Also included are polyphenylene ether copolymers such as copolymers with 6-trimethylphenol and 2-methyl-6-butylphenol. Among them, poly (2,6-dimethyl-1,4-phenylene ether), 2,6-dimethylphenol and 2,3,6-trimethylphenol are preferable, and poly (2,6-dimethyl-1,4-phenylene) is more preferable. Ether) is preferred.

In the case of poly (2,6-dimethyl-1,4-phenylene ether), its reduced viscosity (0.5 g / dl)
Chloroform solution, measured at 30 ° C) is 0.15 to 0.7
It is preferably in the range of 0, more preferably 0.20 to
The range is 0.60. The blending amount of the component (b) can be suitably selected within the range of 20 to 150 parts by weight with respect to 100 parts by weight of the component (a). If the blending amount exceeds 150 parts by weight, the hardness of the obtained plug will be high and the rubber elasticity will be poor, such being undesirable. If the amount is less than 20 parts by weight, rubber elasticity at high temperature (compression set (100 ° C. × 22) as an effect of adding polyphenylene ether is obtained.
(Time)) is not observed, which is not preferable.

Next, the non-aromatic softening agent for rubber used as the component (c) of the present invention is useful for adjusting the hardness of the obtained plug body and imparting flexibility thereto. As the non-aromatic rubber softener provided here, what is called liquid paraffin can be used, and impurities such as aromatic hydrocarbons and sulfur compounds contained in the lubricating oil fraction of petroleum are removed with anhydrous sulfuric acid or fuming sulfuric acid and purified. It is a colorless, transparent, tasteless and odorless oil composed of saturated hydrocarbons. Further, in the present invention, as the component (c), in addition to the above-mentioned liquid paraffin, a petroleum-based softening agent approved by the FDA (US Food and Drug Administration) can also be used.

The blending amount of the softening agent of component (c) is 50 to 300 parts by weight, preferably 100 to 250 parts by weight, relative to 100 parts by weight of component (a). A compounding amount of more than 300 parts by weight is not preferable because oil bleeding out is likely to occur and the resulting plug may have tackiness. Further, the mechanical strength is also lowered, which is not preferable. Further, if the amount is less than 50 parts by weight, it is not preferable from the viewpoint of flexibility and economical efficiency.

Next, the polyolefin-based hydrocarbon resin used as the component (d) of the present invention is useful for improving the processability and / or heat resistance of the obtained plug body. For example, polyethylene, isotactic polypropylene or propylene Other minor α-olefin copolymers, such as propylene-ethylene copolymer, propylene-1-hexene copolymer, propylene-4-methyl-1-pentene copolymer, and poly (4-methyl-1). -Pentene), polybutene-1 and the like. MFR (ASTM-D-1 when using isotactic polypropylene or its copolymer as a polyolefin resin)
238-L condition, 230 ° C.) is 0.1-50 g / 10
Minutes, especially those in the range of 0.5 to 30 g / 10 minutes can be preferably used. The blending amount of the component (d) is 10 parts of the component (a).
It is 5 to 100 parts by weight, preferably 5 to 50 parts by weight, relative to 0 parts by weight. When the amount exceeds 100 parts by weight, the hardness of the obtained plug body becomes too high and the flexibility is lost.
Not only a product having a rubber-like feel cannot be obtained, but rubber elasticity (compression set) and permanent set strain at high temperatures are deteriorated, which is not preferable. In order to maintain the self-closing property of the hole of the stopper after needle removal, liquid leakage will occur unless it has rubber elasticity. Therefore, in the case of compounding more than 100 parts by weight, the self-closing property of the hole after needle removal is maintained. This is because the elasticity of rubber is lost.

Next, a polystyrene resin is added as a component (e) to the composition of the present invention in an amount of 5 to 50 parts by weight relative to 100 parts by weight of the component (a) to mold the obtained plug body. Effective for workability. As the polystyrene resin, those obtained by a known radical polymerization method or ionic polymerization method can be preferably used, and the number average molecular weight thereof is 5,000.
~ 500,000, preferably 10,000-400,
The molecular weight distribution (ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) (Mw / M
n)) is preferably 10 or less.

Next, the organic peroxide used as a crosslinking agent in the present invention is, for example, 2,5-dimethyl-2,
5-di (t-butylperoxy) -hexane, dicumyl peroxide, 2,5-dimethyl-2,5-di (benzoylperoxy) -hexane, t-butylperoxybenzoate, t-butylcumyl peroxide , Diisopropyl benzohydroperoxide, 1,3-bis- (t-butylperoxyisopropyl) -benzene, benzoyl peroxide, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, etc. And one or more organic peroxides can be used. The amount of organic peroxide used here is the amount of components (a) to (d) or (a) to (e).
It can be suitably used in the range of 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the compound consisting of. When the amount of the organic peroxide is less than 0.05 parts by weight, a preferable modified state cannot be obtained, and when it exceeds 5 parts by weight, the composition obtained is excessively crosslinked to deteriorate the flow characteristics during processing. However, excessive cutting of the molecular chain causes stickiness on the surface of the molded product, which is not preferable.

When the composition is partially cross-linked, a cross-linking aid can be used if necessary in order to adjust the degree of cross-linking. Examples of the crosslinking aid used at that time include trimethylolpropane triacrylate, divinylbenzene, ethylene dimethacrylate, diallyl phthalate, quinone dioxime, phenylene bismaleimide, polyethylene glycol dimethacrylate, unsaturated silane compounds (for example, vinyltrimethoxy). Silane, vinyltriethoxysilane, etc.) and the like, and if necessary, one or more kinds can be used in combination. The amount of the cross-linking aid used in combination with the organic peroxide is in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the composition comprising the components (a) to (d) or (a) to (e). It can be preferably used. Further, as a component of the medical plug of the present invention, a hindered amine light stabilizer, an ultraviolet absorber, an antioxidant, an inorganic filler, a colorant, a silicone oil, etc. can be added, if necessary.

As the method for producing the hydrogenated block copolymer composition used as the material for the medical stopper of the present invention, the methods generally used for producing a resin composition or a rubber composition can be adopted, and crosslinking can be carried out. In that case, the temperature at which the decomposition of the added organic peroxide occurs, generally 150 to 250
Under the temperature condition of ° C, for example, a single screw extruder, a twin screw extruder, a Banbury mixer, a heating roll, Brabender, various kneaders and the like can be used for compounding. In order to obtain the plug of the present invention, it is not always necessary to combine the respective components with each other and the crosslinking with the organic peroxide at the same time, and the crosslinking may be performed after the complexation is performed in advance. Furthermore, the components (a) and (b) to (e) may be mixed in any proportions, and after crosslinking with organic peroxide, the remaining components may be further blended.

The compounded medical plug of the present invention can be molded by a commonly used thermoplastic resin molding machine, and can be molded by injection molding, extrusion molding, blow molding,
Although various molding methods such as calender molding and compression molding can be applied, injection molding is preferable as an efficient manufacturing method of the plug body.

[0028]

EXAMPLES The test methods in Examples and Comparative Examples are as follows. The hardness was measured with an A type according to JIS-K-6301. Tensile strength (Kgf / cm ² ) and elongation (%) are
According to JIS-K-6301, the test piece used was a 2 mm thick injection sheet punched with a No. 3 dumbbell.

The compression set (%) is JIS-K-
In accordance with 6301, the strain residual ratio after 25% compression at 100 ° C. for 22 hours was used. The permanent elongation strain (%) is in accordance with JIS-K-6301, and the test piece is a 2 mm thick injection sheet.
It was punched out with a No. type dumbbell. The elongation was 1/2 of the breaking elongation (%).

In the self-occlusion test after removing the needle, a stopper sample was attached to the lower part of the water tank, water was poured into the water tank up to a height of 20 cm from the stopper, and an infusion needle was quickly placed in the center of the stopper. Insert and leave for 1 hour. After 1 hour, remove the needle and check the amount of leakage. The evaluation was performed in the following three stages.

○: No water leakage from needle hole after needle removal △: Some water leakage from needle hole and stop within 1 minute ×: Water leakage from needle hole for 1 minute It does not stop even if it exceeds the limit. As the plug sample to be used, the thickness of 5 mm and the diameter of 25 mmφ shown in the sectional view (a) and front view (b) in FIG.
A disc with a truncated cone shape with a maximum diameter of 5 mm, a minimum diameter of 2 mm, and a depth of 1 mm in the center of both sides is injection molded, and is simulated as heat sterilization treatment that is expected to be performed during actual manufacturing. , 121 ℃ × when attached to the water tank
Tests were conducted for the one that was heat treated for 30 minutes and the one that was not heat treated at all.

As the infusion needle, a commercially available needle having a maximum diameter of about 4 mm was used. Moreover, each compounded component is as follows. (1) Component (a) (a-1): having a structure of hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene, bound styrene content 31% by weight, number average molecular weight 43,000, molecular weight distribution 1.19, a hydrogenated block copolymer having a 1,2-bond content of polybutadiene before hydrogenation of 36% by weight and a hydrogenation rate of 99% is disclosed in JP-A-61-33132 as a Ti-based hydrogenation catalyst. Was synthesized using the component (a-
1).

(A-2): having a structure of hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene and having a bound styrene content of 33% by weight,
A hydrogenated block copolymer having a number average molecular weight of 173,000, a molecular weight distribution of 1.21, a polybutadiene 1,2 bond content before hydrogenation of 36% by weight and a hydrogenation rate of 99% is disclosed in JP-A-61-33.
It was synthesized using the Ti-based hydrogenation catalyst described in Japanese Patent No. 132, and was used as the component (a-2).

(A-3): polystyrene-hydrogenated polybutadiene-polystyrene structure, bound styrene content 30% by weight, number average molecular weight 105,000, molecular weight distribution 1.08, polybutadiene before hydrogenation A hydrogenated block copolymer having a 1,2 bond content of 41% by weight and a hydrogenation rate of 99% was synthesized by using a Ti-based hydrogenation catalyst described in JP-A-61-33132, and the component (a- 3).

(A-4): polystyrene-hydrogenated polybutadiene-polystyrene structure, bound styrene content 28% by weight, number average molecular weight 117,000, molecular weight distribution 1.09 1 of polybutadiene before hydrogenation , A hydrogenated block copolymer having a content of 2-bonds of 39% by weight and a hydrogenation rate of 90% was synthesized by using a Ti-based hydrogenation catalyst described in JP-A-61-33132, and the component (a-4 ).

(A-5): (Polystyrene-hydrogenated polybutadiene) having a structure of ₄ Si, bound styrene content of 30% by weight, number average molecular weight of 201,000, molecular weight distribution of 1.36, before hydrogenation A hydrogenated block copolymer having a 1,2-bond content of polybutadiene of 40% by weight and a hydrogenation rate of 99% was synthesized by using a Ti-based hydrogenation catalyst described in JP-A-61-33132, and a component ( a-5).

(A-6): Polystyrene-hydrogenated polyisoprene-polystyrene structure, bound styrene content 34% by weight, number average molecular weight 141,000, molecular weight distribution 1.20, poly- A hydrogenated block copolymer of styrene / isoprene block copolymer having 94% by weight of 1,4 bonds of isoprene, 6% by weight of 3,4 bonds and 99% of hydrogenation rate of polyisoprene is disclosed in Japanese Patent Application Laid-Open No. Sho 61-61. -331
It was synthesized using the Ti-based hydrogenation catalyst described in JP-A No. 32 to give Component (a-6). (2) Component (b) Poly (2,6-dimethyl-1,4-phenylene) ether (reduced viscosity;
0.54) was synthesized. (3) Component (c) Idemitsu Kosan Diana Process Oil PW-380 (paraffin-based process oil, kinematic viscosity; 381.6 cst
(40 ° C.), 30.1 cst (10 ° C.), ring analysis; C _N
= 27%, C _P = 73%) (4) Component (d) Polypropylene resin manufactured by Asahi Kasei Corporation, M1600 (MFR
(230 ° C., 2.16 kg) 14 g / 10 minutes) (5) Component (e) Asahi Kasei polystyrene resin, polystyrene 685 (M
FR (200 ° C., 5.0 kg) 2 g / 10 minutes) (6) Organic peroxide; manufactured by NOF CORPORATION, Perhexa 25B (2,5-dimethyl-2,5-di (t-butylperoxy) hexane) ( 7) Cross-linking aid; trimethylolpropane triacrylate manufactured by Seiko Chemical Co., Ltd.

[0038]

Examples 1 to 6 As hydrogenated block copolymers (a-
Using (3), the components shown in Table 1 were mixed in advance with a Henschel mixer, and then melt-kneaded under the condition of 270 ° C. in a 30 mm diameter twin-screw extruder to obtain thermoplastic elastomer pellets. Then, to 100 parts by weight of the obtained pellets, an organic peroxide and a crosslinking aid were added in the amounts shown in Table 1 and reacted at 220 ° C. to obtain partially crosslinked thermoplastic elastomer pellets. This was evaluated as an injection molded product, and the results are shown in Table 1.

From these results, the medical stopper of the present invention has 10
It was found that the material has excellent compression set and permanent set strain at 0 ° C., and also has excellent self-closing property of the hole after needle drawing.

[0040]

Comparative Examples 1 to 4 As a hydrogenated block copolymer (a-
Using 3), the components shown in Table 1 were kneaded in the same manner as in Examples 1 to 6, and molded and evaluated. The results are shown in Table 1. From this result, it was found that the plug molded with the thermoplastic elastomer outside the scope of the present invention was inferior in compression set and permanent set strain at 100 ° C., and was also inferior in the self-closing property of the hole after needle withdrawal.

[0041]

Examples 7 to 10 As hydrogenated block copolymers (a-
2), (a-4), (a-5), and (a-6) were used, and the components shown in Table 2 were kneaded in the same manner as in Examples 1 to 6,
It was molded and evaluated. The results are shown in Table 2. From these results, when the structure of the hydrogenated block copolymer is within the range described in the present invention, the medical stopper of the present invention is excellent in compression set and permanent set strain at 100 ° C. It was found that the self-closing property of the hole was excellent.

[0042]

Comparative Example 5 Using (a-1) as the hydrogenated block copolymer, the components shown in Table 2 were kneaded and molded in the same manner as in Examples 1 to 6 and evaluated. The results are shown in Table 2. From this result, it was found that the plug formed of the thermoplastic elastomer having the hydrogenated block copolymer having a number average molecular weight of less than 50,000 was inferior in the self-closing property of the hole after needle withdrawal and was not preferable. .

[0043]

[Examples 11 to 12] The medical stoppers obtained in Examples 4 and 10 were subjected to a material and eluent test according to the rubber stopper test method for liquid infusion of the 12th revised Japanese Pharmacopoeia. The results are shown in Table 3. From this result, it was found that the medical plug of the present invention complies with the standard.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

EFFECT OF THE INVENTION The medical stopper of the present invention has heat resistance capable of withstanding steam sterilization required as a medical stopper, self-closing property of a hole after needle withdrawal, permanent elongation, rubber elasticity and compression set. It is an improved product, and since it does not contain sulfur like vulcanized rubber, it is non-toxic because it does not elute sulfur in the drug solution or blood that comes into contact with the stopper and does not contain heavy metals such as zinc. It is hygienic without reacting with sulfur and metals.

Since the medical plug of the present invention can be injection-molded, the molding time is significantly shortened as compared with the conventional one including the vulcanization step, and the mold releasability is good, so that the productivity is excellent. Furthermore, when injection molding is performed by the cold runner method, the runner portion and the sprue portion after molding are thermoplastic elastomers, and thus are recyclable and economical.

[Brief description of drawings]

FIG. 1 is a sectional view and a front view of a medical stopper of the present invention used for a self-occlusive property test.

Claims (1)

[Claims] 1. A hydrogen-containing block copolymer comprising (a) a polymer block A mainly containing at least two vinyl aromatic compounds and a polymer block B mainly containing at least one conjugated diene compound. 100 parts by weight of a hydrogenated block copolymer having a number average molecular weight of 50,000 to 250,000 obtained by adding the (b) bonding unit is represented by the following formula (1): (Here, R1, R2, R3, and R4 are each selected from the group consisting of hydrogen, halogen, hydrocarbon, and substituted hydrocarbon group, and may be the same or different from each other.)
20 to 150 parts by weight of a polyphenylene ether resin which is a homopolymer and / or a copolymer having a reduced viscosity (0.5 g / dl chloroform solution, measured at 30 ° C.) of 0.15 to 0.70. (C) 50 to 300 parts by weight of a non-aromatic softening agent for rubber and (d) 5 to 100 parts by weight of a polyolefin hydrocarbon resin are partially crosslinked in the presence of organic peroxide to form a thermoplastic elastomer. A medical plug body.