JP4947972B2 - Medical stopper - Google Patents

Description

  The present invention relates to a medical resin composition and a medical stopper using the same, and more specifically, the present invention relates to a medical resin composition excellent in liquid leakage resistance, needle sticking property, resealability, and the like. The present invention relates to a medical stopper using the same. The medical stopper of the present invention is suitably used for a transfusion container, a drug solution container, a mixed injection stopper such as hemodialysis and peritoneal dialysis.

In Patent Document 1 (Japanese Patent Laid-Open No. 8-258857), a cylindrical plug is formed by injection molding of polypropylene resin, and a packing made of a non-vulcanized thermoplastic elastomer is integrally fusion-molded at one end of the plug. A chemical container is disclosed in which the bottomed cylindrical stopper is fixed to the mouth of the container by heat welding.
However, the plug obtained according to Patent Document 1 does not satisfy the performances required for medical plugs (leakage resistance, needle sticking property, resealability, etc.).
Patent Document 2 (Japanese Patent Laid-Open No. 9-601) discloses a composition containing (a) a specific block copolymer, (b) a polyolefin resin, and (c) a non-aromatic rubber softener. A rubber stopper for an infusion bag obtained by molding into the shape is disclosed. This medical stopper is useful because it satisfies all of the above performances at a satisfactory level.
JP-A-8-258857 JP-A-9-601

  An object of the present invention is to provide a medical resin composition in which, among the performances of the medical stopper disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 9-601), the liquid leakage resistance and the resealability are further improved. Another object of the present invention is to provide a medical stopper using the same.

The present invention is as follows.
(1)
(A) From at least two polymer blocks A mainly composed of an aromatic vinyl compound having a weight average molecular weight of 50,000 to 550,000 and at least one polymer block B mainly composed of a conjugated diene 40 to 150 parts by mass of a block copolymer and / or a hydrogenated block copolymer obtained by hydrogenating the block copolymer,
(B ) 1 to 45 parts by mass of a mixture of hydrogenated petroleum resin and phenylene ether resin,
A medical stopper comprising a medical resin composition comprising (c) a peroxide-decomposable olefin resin 10 to 60 parts by mass and (d) a non-aromatic rubber softener 40 to 280 parts by mass. .

(2) The polymer block B in the block copolymer (a) is mainly composed of isoprene as a conjugated diene, and 70 to 100% by mass of the isoprene has a 1,4-microstructure. The medical stopper according to (1) above, wherein at least 90% of the heavy bonds are hydrogenated, and the polymer block A is 5 to 70% by mass of the total component (a).

The medical resin composition of the present invention comprises a specific proportion of (a) a block copolymer, (b ) a mixture of a hydrogenated petroleum resin and a phenylene ether resin, (c) a peroxide-decomposable olefin resin, (d) A composition comprising a non-aromatic rubber softener, and (b ) further improving liquid leakage resistance and resealability by blending a mixture of hydrogenated petroleum resin and phenylene ether resin. In addition, the moldability is excellent, and when this is used for a medical instrument such as a medical rubber stopper, the assembly property and the elution safety are excellent, and no liquid leakage occurs.

Hereinafter, the components and blending ratios of the composition of the present invention will be described in detail.
(A) Component:
The component (a) in the composition of the present invention is composed of at least two polymer blocks A mainly made of an aromatic vinyl compound (hereinafter sometimes referred to as an aromatic vinyl compound as a main component) and a conjugated diene compound. A block copolymer comprising at least one polymer block B produced mainly (hereinafter sometimes referred to mainly as a conjugated diene compound), or a block copolymer obtained by hydrogenation thereof, or a mixture thereof is there. For example, an aromatic vinyl compound-conjugated diene compound block copolymer having a structure such as ABA, BABA, ABBABA or the like, or hydrogenating this Can be obtained. The above (hydrogenated) block copolymer (hereinafter, (hydrogenated) block copolymer means a block copolymer and / or a hydrogenated block copolymer) is preferably an aromatic vinyl compound as a whole. 5 to 60% by mass, more preferably 20 to 50% by mass.

  The polymer block A mainly composed of an aromatic vinyl compound is preferably a homopolymer block consisting only of an aromatic vinyl compound, or more than 50% by mass, preferably 70% by mass or more of an aromatic vinyl compound and an optional component. For example, it may be a copolymer block made from a conjugated diene compound.

  The polymer block B mainly composed of a conjugated diene compound is preferably a homopolymer block consisting only of a conjugated diene compound, or more than 50% by weight, preferably 70% by weight or more of a conjugated diene compound and optional components such as aromatic It may be a copolymer block made from a vinyl compound.

  In each of the polymer block A mainly composed of the aromatic vinyl compound or the polymer block B mainly composed of the conjugated diene compound, the distribution of units derived from the conjugated diene compound or the aromatic vinyl compound in the molecular chain is It may be random, tapered (in which the monomer component increases or decreases along the molecular chain), partially in a block form, or any combination thereof. When there are two or more polymer blocks A mainly composed of aromatic vinyl compounds or polymer blocks B mainly composed of conjugated diene compounds, each polymer block has a different structure even though each has the same structure. There may be.

  As the aromatic vinyl compound constituting the (hydrogenated) block copolymer, for example, one or more kinds can be selected from styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, etc. Styrene is preferred. Further, as the conjugated diene compound, for example, one or more kinds are selected from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., among which butadiene, isoprene, and these The combination of is preferable.

  In the polymer block B mainly composed of a conjugated diene compound, the microstructure can be arbitrarily selected. For example, in the polybutadiene block, the 1,2-microstructure is preferably 20 to 50% by mass, particularly preferably 25 to 45% by mass. In the polyisoprene block, 70 to 100% by mass of isoprene has a 1,4-microstructure, and at least 90% by mass of an aliphatic double bond derived from isoprene is preferably hydrogenated.

  The number average molecular weight of the (hydrogenated) block copolymer is preferably in the range of 5,000 to 1,500,000, more preferably 10,000 to 550,000, and particularly preferably 100,000 to 400,000. It is. The weight average molecular weight is in the range of 50,000 to 550,000, more preferably 100,000 to 300,0000, and particularly preferably 150,000 to 200,000. If the mass average molecular weight is outside the range of 50,000 to 550,000, the liquid leakage resistance and resealability cannot be improved. Further, when the mass average molecular weight is 300,000 or less, the liquid leakage resistance and resealability can be improved. The molecular weight distribution (ratio (Mw / Mn) of mass average molecular weight (Mw) to number average molecular weight (Mn)) is preferably 10 or less, more preferably 5 or less, and particularly preferably 2 or less.

  The molecular structure of the (hydrogenated) block copolymer may be linear, branched, radial, or any combination thereof.

  Many methods for producing these block copolymers have been proposed. As typical methods, for example, a lithium catalyst or a Ziegler-type catalyst is prepared by the method described in Japanese Patent Publication No. 40-23798. It can be obtained by block polymerization in an inert medium. Any known method can be used for hydrogenation. For example, a hydrogenated block copolymer can be obtained by hydrogenating the block copolymer obtained by the above method in the presence of a hydrogenation catalyst in an inert solvent.

In the present invention, a particularly preferred (hydrogenated) block copolymer is such that the polymer block B is mainly composed of isoprene as a conjugated diene, 70 to 100% by mass of isoprene has a 1,4-microstructure, and At least 90% by mass of the double bond based on isoprene is hydrogenated, and the polymer block A is 5 to 70% by mass of the total (hydrogenated) block copolymer. More preferred is a hydrogenated block copolymer. Particularly preferred is the above hydrogenated block copolymer in which 90 to 100% by mass of isoprene has a 1,4-microstructure.
When the 1,4-microstructure is 70% by mass or more, resealability and bleed resistance can be improved. When the 1,4-microstructure exceeds 90% by mass, resealability and bleed resistance are further remarkably improved.
Further, since at least 90% of the double bond based on isoprene is hydrogenated, a polymer block mainly composed of isoprene can be morphologically converted to an olefinic compound polymer block, which will be described below. Compatibility with olefin resin is increased.

Examples of the component (a) include styrene / isoprene / styrene copolymer (SIS), styrene / ethylene / propylene / styrene copolymer (SEPS), styrene / butadiene / isoprene / styrene copolymer (SBIS), styrene / An ethylene / ethylene / propylene / styrene copolymer (SEEPS) may be mentioned, among which SEPS and SEEPS are preferable.
As such a block polymer, commercially available polymers such as Septon 4000 series (trade name, manufactured by Kuraray Co., Ltd.) can be used.
In the present invention, a more preferable (hydrogenated) block copolymer contains 20 to 35% by mass of an aromatic vinyl compound, and the mass average molecular weight of the (hydrogenated) block copolymer is 150,000 to 200,000. 000 (hydrogenated) block copolymer. Resealability is further improved by using the above-mentioned combination (hydrogenated) block copolymer.

(B) Component:
(B) component in the composition of the present invention is a mixture of hydrogenated petroleum resin and polyphenylene ether resin.
Hydrogenated petroleum resins are hydrides of aromatic hydrocarbons, hydrides of terpene resins, etc., specifically styrene, α-methylstyrene, vinyltoluene, vinylxylene, propenylbenzene, indene, methylindene, ethyl Hydrogenated resins obtained by polymerizing mainly one kind or a mixture of two or more kinds of aromatic unsaturated hydrocarbons and / or terpenes such as indene, and secondary oils during cracking and reforming of petroleum. Examples thereof include a hydrogenated resin obtained by polymerizing a distillate having a boiling point of 20 to 300 ° C, particularly 150 to 300 ° C.
In the present invention, the hydrogenated petroleum resin preferably has a softening point of 130 ° C to 300 ° C. If it is less than 130 ° C., there is a possibility of bleeding at the time of sterilization, and if it exceeds 300 ° C., melt kneading may be difficult when producing the composition.
Although the usage-amount of hydrogenated petroleum resin changes with the softening points, it is 1-45 mass parts with respect to 40-150 mass parts of component (a), Preferably it is 2-30 mass parts, More preferably, it is 5-20 mass parts. is there. Liquid leakage occurs when the amount used is outside the range of 1 to 45 parts by mass.

The phenylene ether resin used in the present invention is poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-dimethylphenol, 2,3,6-trimethylphenol) produced by oxidative coupling. Copolymers such as (2,3,6-trimethyl-1,4-phenylene) ether, 2,6-dimethylphenol and 2,3,6-trimethylphenol, and these polymers are unsaturated such as maleic anhydride A polymer modified with carboxylic acid or the like. Since ordinary polyphenylene ether resin is difficult to process by itself, it is modified by copolymerization or blending with polystyrene resin, etc., but blending with polystyrene resin is generally used. Is. Examples of the polystyrene resin include general-purpose polystyrene (GPPS), impact-resistant polystyrene (HIPS) reinforced with a rubber component, styrene-butadiene copolymer (high styrene SBS) with a large amount of styrene component, and styrene-maleic anhydride copolymer. Examples thereof include a polymer, a styrene-acrylonitrile copolymer, a styrene-acrylonitrile-butadiene copolymer, and a styrene-methyl methacrylate copolymer. Examples of the styrene elastomer used in the present invention include a styrene-butadiene copolymer, a styrene-ethylene-propylene copolymer, and a styrene-ethylene-butene copolymer. These copolymers may be random copolymers or block copolymers.
The usage-amount of a phenylene ether-type resin is 1-45 mass parts with respect to 40-150 mass parts of component (a), Preferably it is 2-30 mass parts, More preferably, it is 5-20 mass parts. Liquid leakage occurs when the amount used is outside the range of 1 to 45 parts by mass.

(C) Component:
The component (c) in the composition of the present invention is a peroxide-decomposable olefin resin.
Specifically, the peroxide-decomposable olefin resin is a high molecular weight homo-type polypropylene such as isotactic polypropylene or propylene and a small amount of other α-olefin such as ethylene, 1-butene, 1-hexene, 4- A copolymer with methyl-1-pentene or the like is preferred.
The MFR (ASTM-D-1238, L condition, 230 ° C.) of the resin is preferably 0.1 to 10 g / 10 minutes, more preferably 0.1 to 5 g / 10 minutes, still more preferably 0.1 to 3 g. / 10 minutes. When the MFR of the peroxide-decomposable olefin resin is less than 0.1 g / 10 min, the moldability of the composition is lowered, and when the MFR exceeds 10 g / 10 min, the rubber elasticity of the composition is deteriorated.

  (C) The mixture ratio of a component is 10-60 mass parts with respect to 40-150 mass parts of component (a), Preferably it is 20-50 mass parts, More preferably, it is 25-45 mass parts. If the amount is less than 10 parts by mass, the moldability of the resulting resin composition deteriorates, and if it exceeds 60 parts by mass, the flexibility and rubber elasticity of the obtained resin composition deteriorate, which is not preferable.

(D) Component:
The component (d) in the composition of the present invention is a non-aromatic rubber softener. As a specific example, a mineral oil system or a synthetic resin system is suitable. Mineral oil-based softeners are a mixture of three of an aromatic ring, a naphthene ring, and a paraffin chain, and those having 50% or more of the total number of carbon atoms in the paraffin chain are called paraffinic, Those having 30 to 45% carbon are classified as naphthenic and those having more than 30% aromatic are called aromatic. Among these, preferred mineral oil softeners as the component (d) of the present invention are naphthenes and paraffins, and are aromatic hydrocarbons of 30% or less. Aromatics are less preferred in terms of dispersibility with respect to the component (a) used in the present invention.
As the properties of the mineral oil softener, those having a kinematic viscosity at 37.8 ° C. of 20 to 500 cSt, a pour point of −10 to −15 ° C., and a flash point (COC) of 170 to 300 ° C. are used.
As the synthetic resin softener, polybutene, low molecular weight polybutadiene, and the like can be used, but a mineral oil softener is preferred.

  (D) The mixture ratio of a component is 40-280 mass parts with respect to 40-150 mass parts of component (a), Preferably it is 50-100 mass parts. If the amount is less than 40 parts by mass, the productivity of pellets tends to be difficult and the assembly property tends to be poor. If the amount exceeds 150 parts by mass, the hardness of the molded product decreases, the molded product deforms, and the molded product slides. This is not preferable because the property (sliding property) tends to deteriorate.

  The composition of the present invention is added within the range not impairing its basic performance, other olefin polymers, polymers other than essential components such as styrene polymers, or inorganic fillers such as calcium carbonate, talc, mica and carbon black. Ingredients can be added. Furthermore, additives such as an antioxidant, an ultraviolet absorber, a slip agent, and a fluidity improver can be blended according to the target quality.

The composition of the present invention can be prepared by mechanically melting and kneading the above components. The temperature for melt kneading is usually 120 to 240 ° C, preferably 140 to 200 ° C. Specifically, a general melt kneader such as a Banbury mixer, various kneaders, a single screw or twin screw extruder can be used for the melt kneading.
Moreover, the molding method of thermoplastic resins, such as injection molding, extrusion molding, and blow molding, can be applied to the composition of the present invention.

  The composition of the present invention is particularly useful as a medical resin composition or a medical rubber stopper resin composition. The composition of the present invention achieves further improvement in liquid leakage resistance and resealability and is excellent in moldability. When this composition is used for a medical device such as a medical rubber stopper, it is easy to assemble and dissolve. Excellent in liquidity and does not cause liquid leakage. Therefore, it is particularly useful as a bottle for storing a chemical solution and a stopper for a plastic bag.

In order to produce a medical rubber stopper using the composition of the present invention, a desired molding method can be applied. For example, the composition can be melted at 200 to 240 ° C. and molded into a desired shape using an injection molding machine under conditions of an injection pressure of about 1000 to 2000 kg / cm ² . Of course, the above molding method is only an example, and other molding such as compression molding can be performed.

Hereinafter, the present invention will be described more specifically with reference to examples.
In the following examples and comparative examples, test methods used for various evaluations are as shown below.
1) Hardness: In accordance with JIS K 6301, a 6.3 mm pressure press sheet was used as a test piece. In the use of a medical rubber plug, the hardness is suitably 10 to 30 in terms of A hardness.
2) Tensile strength: In accordance with J1S K 6251, the test piece was a 1 mm thick press sheet punched into No. 3 with a dumbbell and used. The tensile speed was 500 mm / min.
3) 100% modulus: Based on J1S K 6251, the test piece was a 1 mm thick press sheet punched into No. 3 with a dumbbell and used. The tensile speed was 500 mm / min.
4) Tensile elongation: In accordance with JIS K 6301, a 1 mm thick press sheet was punched into a No. 3 type with a dumbbell and used. The tensile speed was 500 mm / min.
5) Tear strength: In accordance with JIS K 6252, the test piece was a 1 mm thick press sheet punched into an angled shape without cut. The moving speed was 500 mm / min.
6) MFR: Measured according to JIS K 7210 at 230 ° C. and a load of 2.16 kg.
7) Compression set: In accordance with JIS K 6262, a 6.3 mm-thick press sheet was used as a test piece. The measurement was performed under the conditions of 23 ° C. × 22 hours, 70 ° C. × 22 hours, 120 ° C. × 22 hours, and 25% deformation.
8) Liquid leakage test: A test piece having a diameter of 22 mm and a thickness of 5.6 mm was prepared by an injection molding method, and the test piece was mounted on a fitting unit having an internal volume of 1000 ml. In addition, 500 ml of water was introduced into the unit as a liquid. Subsequently, a plastic needle having a thickness of 3 mm was inserted and removed 15 times, the presence or absence of leakage was observed, and the case where no leakage occurred was counted. At the same time, the maximum and average values of the liquid that leaked when the plastic needle was removed were also examined.

Moreover, each compounding component used by the Example and the comparative example is as follows.
(A) Hydrogenated block copolymer:
Kuraray's “Septon 4044” (Kuraray's styrene / ethylene / ethylene / propylene / styrene copolymer, styrene content 30% by mass, isoprene content 70% by mass, (isoprene has 1,4-microstructure) Having a mass average molecular weight of 173,000, a molecular weight distribution of 1.23, a hydrogenation rate of 90% or more, and a hydrogenated derivative of a styrene-butadiene-isoprene-styrene block copolymer).
In Table 1 below, it is described as 4044.

Kuraray's “Septon 4055” (Kuraray's styrene / ethylene / ethylene / propylene / styrene copolymer, styrene content 30% by mass, isoprene content 70% by mass, (isoprene has 1,4-microstructure) Number average molecular weight: 250,000, mass average molecular weight: 290,000, molecular weight distribution: 1.3, hydrogenation rate of 90% or more, hydrogenated derivative of styrene-butadiene-isoprene-styrene block copolymer).
In Table 1 below, it is described as 4055.

“Clayton G1654H” manufactured by Clayton Japan Co., Ltd. (styrene / ethylene / butadiene / styrene copolymer manufactured by Clayton Japan Co., styrene content 29% by mass, mass average molecular weight: 189,000, molecular weight distribution: 1.33, hydrogenation rate 90% or more, hydrogenated derivative of styrene-butadiene-styrene block copolymer).
In Table 1 below, it is described as G1654H.

Comparative component (a): “SIBSTER 103T” manufactured by Kaneka Corporation (styrene / isoprene / butadiene / styrene copolymer manufactured by Kaneka Co., Ltd., styrene content of 31% by mass, number average molecular weight: 96,000, mass average molecular weight: 142, 000, molecular weight distribution: 1.09, unsaturated bond: 0%, styrene-isobutylene-styrene block copolymer obtained by living cationic polymerization).
In Table 1 below, it is described as 103T.

(B) Hydrogenated petroleum resin, phenylene ether-based resin “I-Marp P-140 (hydrogenated petroleum resin)” manufactured by Idemitsu Kosan Co., Ltd.
"Clearon P-135 (hydrogenated petroleum resin)" manufactured by Yasuhara Chemical
"Zylon X0108 (phenylene ether resin)" manufactured by Asahi Kasei Chemicals
Comparison (b) component: “G200C (polystyrene resin)” manufactured by Toyo Styrene Co., Ltd.

(C) Peroxide-decomposable olefin resin “J739E” manufactured by Mitsui Chemicals, block polypropylene, MFR (ASTM-D-1238, L condition (2.16 kg), 230 ° C.) = 54 g / 10 minutes In Table 1 below It is described as J739E.

(D) Softener for non-aromatic rubber “PW-380” manufactured by Idemitsu Kosan Co., Ltd., hydrogenated paraffin oil, molecular weight: 750
In Table 1 below, it is described as PW380.

Crosslinking aid:
Nippon Kasei Co., Ltd. “TAIC”, triallyl isocyanurate

Organic peroxide:
“Perhexa 25B” manufactured by NOF Corporation, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane

(Examples 1-9 and Comparative Examples 1-13)
The compounding formulation shown in Table 1 (the unit in the table is part by mass) is melt-kneaded at a set temperature of 200 ° C. by a twin screw extruder with L / D = 42 and cylinder diameter of 45 mm to obtain resin composition pellets. It was. Using this pellet, the above-described various evaluation sheets and test pieces of medical stoppers were molded.
The molding conditions of the medical plug are as follows: resin temperature: 180-240 ° C., injection speed: 50-100 mm / second, injection time: 2-10 seconds, mold temperature: 30-50 ° C., cooling time: 10-30 seconds is there.
The evaluation results are shown in Table 1.
Examples 1, 2, 3, 4, 6, 7, and 8 are reference examples.

As can be seen from Table 1 above, the composition of the present invention comprises a specific proportion of (a) a block copolymer, (b ) a mixture of a hydrogenated petroleum resin and a phenylene ether resin, and (c) a peroxide-decomposable olefin. Since a resin and (d) a softener for non-aromatic rubber are blended, physical properties such as hardness and compression set and liquid leakage resistance are good.
On the other hand, the example which does not mix | blend any of the said (a)-(d) component of this invention, the example which mix | blended the comparison component, and also components other than said (a)-(d) component, for example, bridge | crosslinking In the example in which an auxiliary agent or a peroxide was blended, the liquid leakage resistance was inferior.

  The composition of the present invention achieves further improvement in liquid leakage resistance and resealability and is excellent in moldability. When this composition is used for a medical device such as a medical rubber stopper, it is easy to assemble and dissolve. Excellent in liquidity and does not cause liquid leakage.

Claims (2)

(A) From at least two polymer blocks A mainly composed of an aromatic vinyl compound having a weight average molecular weight of 50,000 to 550,000 and at least one polymer block B mainly composed of a conjugated diene 40 to 150 parts by mass of a block copolymer and / or a hydrogenated block copolymer obtained by hydrogenating the block copolymer,
(B ) 1 to 45 parts by mass of a mixture of hydrogenated petroleum resin and phenylene ether resin,
A medical stopper comprising a medical resin composition comprising (c) 10 to 60 parts by mass of a peroxide-decomposable olefin resin, and (d) 40 to 280 parts by mass of a softener for a non-aromatic rubber. . The polymer block B in the block copolymer (a) is mainly composed of isoprene as a conjugated diene, and 70 to 100% by mass of the isoprene has a 1,4-microstructure, and has a double bond based on the isoprene. The medical stopper according to claim 1, wherein at least 90% is hydrogenated, and the polymer block A is 5 to 70% by mass of the total component (a).