JPS6137242A - Stopcock for transfusion liquid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in an infusion stopper made of a special thermoplastic elastomer.

[Technical background of the invention and its problems]

Specifically, an infusion stopper is used by being inserted into the mouth of a container containing an infusion such as Ringer's solution. When this stopper is used with a syringe needle inserted into it, it is necessary that the hole of the syringe needle is not clogged with debris from the material of the stopper and that the inside of the container is kept in communication with the atmosphere. Also,
It is necessary that the infusion solution does not leak from the insertion point of the injection needle when the injection needle is removed.

By the way, conventional stopcocks for infusions are made of isobutylene.
Vulcanized rubber materials such as isoprene (butyl rubber), chlorinated butyl rubber, natural rubber, polyisoprene rubber, and polybutadiene rubber are used.

However, stoppers made of vulcanized rubber have various problems as shown below.

(1) Conventional stopcocks are not completely satisfactory in terms of medical hygiene. In particular, even if the transmittance test (measurement of the amount of fine particles eluted from the material) and evaporation residue test, which are part of the eluate tests stipulated by the Japanese Pharmacopoeia's rubber stopper test method for infusion solutions, are within the standards, There are problems such as the polymerization solvent, additives, etc. remaining in the vulcanized rubber eluting into the interior of the infusion container over time.

(2) In manufacturing stopcocks, there is a problem in that the process becomes complicated from the viewpoint of placing emphasis on medical hygiene. In other words, during manufacturing, it is not necessary to strictly select the types and amounts of various additives to be mixed into rubber, such as vulcanizing agents, vulcanization accelerators, vulcanization accelerators, softeners, and various inorganic fillers. Of course, the vulcanization process also requires very complicated operations such as carefully controlling conditions such as time and temperature, and cleaning with several types of chemicals after molding.

(3) In finishing the stopper into a product shape, the material has poor thermoplasticity, which reduces productivity and makes it difficult to mold products with complex shapes. Further, when removing pars after molding, problems such as adhesion of cutting debris and foreign matter occur.

(4) During use, when inserting a syringe needle into the stopper to draw in and out infusions, the resistance to inserting the needle is large and workability is difficult.

(5) When inserting and removing the injection needle from the stopper, a so-called coring phenomenon occurs in which a portion of the rubber is broken off, and there is a problem in that the broken pieces of rubber are mixed into the infusion as foreign matter. Also,
There is a problem in that infusion fluid leaks from the stopper after the needle is removed.

[Purpose of the invention]

The present invention does not elute residual solvents, additives, etc. over time, and
It has good moldability, does not require cleaning after molding, and is easy to insert the injection needle, preventing coring phenomenon when inserting and removing the injection needle, and preventing leakage of infusion after removal. It is an object of the present invention to provide a stopper for infusion that is easy to manufacture.

[Summary of the invention]

The present invention is based on (a) general formula % formula %) [However, A in the formula is a polymer block consisting of a monovinyl-substituted aromatic hydrocarbon and having a molecular weight of 15,000 to 60,000, and B is a molecular weight consisting of a conjugated diene elastomer. 6
0000 to 180000 polymer blocks, n is 1 to 5
indicates an integer. 100 parts by weight of a hydrogenated derivative of a copolymer represented by ], (b) 100 to 185 parts by weight of a softener for paraffinic rubber, and (C) 20 to 60 parts by weight of a crystalline propylene polymer resin. and the hardness (J Is-6301) is 30
It is characterized in that it is partially or entirely composed of a thermoplastic elastomer composition of No. 60 to 60. According to the present invention, as described above, there is no elution of residual solvents, additives, etc. over time, the moldability is good, there is no need for washing treatment after molding, and furthermore, the injection needle can be easily inserted, and the injection needle can be easily inserted. It is possible to obtain an easy-to-manufacture stopper for infusion that can prevent occurrence of coring during insertion and withdrawal of a needle, leakage of infusion after withdrawal, etc.

Various monovinyl-substituted aromatic hydrocarbon monomers constituting the polymer block A represented by the general formula of component (a) above include various monomers, particularly styrene, α
- Methylstyrene is preferred. The conjugated diene monomer of the polymer block B having the same general formula is preferably butadiene or isoprene, and a mixture of both may be used. When butadiene is used as a single conjugated diene monomer to form polymer block B, the 1,2-microstructure in the microstructure of the polybutadiene is 20 to 50% in order to maintain elastomer properties. It is preferable to adopt polymerization conditions such that the 1.2-microstructure is 35
~45% is suitable. In addition, polymer block B
Preferably, the proportion of the copolymer in the copolymer is at least 65% by weight.

The molecular weights of the polymer block A and polymer block B are the most important in constituting component (a). The lower limit of the molecular weight of both polymer blocks A and B (1500016
0000), when evaluated as a stopper, the heat resistance during the steam sterilization process will be poor, the stopper will come off from the container, the stopper will be greatly deformed, and furthermore, the mechanical strength and compression set will be poor, and the core Ring phenomenon and infusion leakage phenomenon occur. On the other hand, if the molecular weight of both polymer block A and polymer block A deviates from the upper limits (60,000 and 180,000), the molecular weight becomes too large, which impedes moldability, which is one of the most important characteristics of thermoplastic elastomers, and short-circuits. This leads to various problems such as shot, delamination, and gelation. The preferred molecular weight of such polymer block A is 200
The preferred molecular weight of polymer block B is in the range of 90,000 to 150,000.

The method for producing the block copolymer of the general formula described above is as follows. Many methods have been proposed, but representative methods include, for example, Japanese Patent Publication No. 42-8704 and Japanese Patent Publication No. 43-6.
There is a method described in No. 636.

In the hydrogenated derivative of the block copolymer as component (a), at least 50% of the olefin type double bonds in the polymer block B is hydrogenated during its production.
, preferably 80% or more is hydrogenated, and preferably 25% or less of the aromatic unsaturated bonds in the polymer block A are hydrogenated. These ingredients (a) include:
A commercially available polymer such as KRAT'ON-G (trade name manufactured by Shell Chemical Company) can be used.

The softener for paraffin rubber as the above component (b) is:
The number of carbon atoms in the paraffin chain accounts for 50% or more of the total number of carbon atoms. Note that mineral oil-based rubber softeners, commonly called process oils or extender oils, are used to soften, increase volume, and improve processability of rubber, and are composed of a combination of aromatic rings, naphthenic rings, and n-paraffin chains. It is a mixture of Of these, the number of carbon atoms in the naphthene ring is 30 to 45%
Those containing more than 30% aromatic carbon are called naphthenic and aromatic. Softeners other than paraffin-based rubber softeners used in the present invention have poor compatibility and dispersibility with component (a), deteriorate mechanical properties, and have a strong odor, making them unsuitable as stopper components. It's inappropriate. The properties of such a paraffin rubber softener include a kinematic viscosity of 20 to 500 centistokes at 37.8°C and a flash point of 170 centistokes.
Those exhibiting a temperature of ~300°C are preferred. Further, the blending ratio of the paraffin rubber softener needs to be 100 to 185 parts by weight with respect to component (a>100 parts by weight).

The reason for this is that if the amount of the softener is less than 100 parts by weight, the flexibility and rubber elasticity will decrease, causing leakage of the infusion, and the fluidity will decrease, resulting in poor appearance and moldability of the final product. It interferes with sexuality. On the other hand, if the amount of softener exceeds 185 parts by weight, bleed-out of the softener tends to occur.
There is a risk that the stopper will become sticky, and the compression set properties will deteriorate, causing leakage of the infusion fluid.

As the crystalline propylene polymer resin of component (C), a propylene homopolymer can be used, but copolymers of propylene and various α-olefins are preferred. Examples of the α-olefin include ethylene, butene-1, hexane-1,4-methylpentene-1, etc., and ethylene, butene-1, and hexane-1 are particularly preferred. α−
The copolymerization ratio of olefin can be expressed by the density of the produced copolymer, and is preferably in the range of 0.883 to 0.901'J/cm3. The amount of crystalline propylene polymer resin blended is 20 parts by weight per 100 parts by weight of component (a).
~60 parts by weight is required.

The reason for this is that if the amount of polymer resin is less than 20 parts by weight, moldability will be poor and appearance defects (occurrence of weld lines and delamination) will occur. On the other hand, if the suspension of the polymer resin exceeds 60 parts by weight, the hardness of the stopper becomes too high, causing a leakage phenomenon of the infusion solution after the needle is inserted and removed.

In order to prepare the thermoplastic elastomer composition consisting of the above components (a), (b) and (C), for example, a single screw extruder,
A method using a general melt mixer such as a twin-screw extruder, a Banbury type internal mixer, or various kneaders is adopted. The temperature at which the wires are crossed is preferably the melting temperature of the crystalline propylene polymer resin of component (C), for example, in the range of about 180 to 250°C. Regarding time, if an extruder is used, the general residence time of the machine,
In the case of an internal mixer, about 5 to 20 minutes is preferable. In addition, when preparing the composition, various stabilizers such as a heat stabilizer, an ultraviolet absorber, and an anti-gamma ray stabilizer according to a sterilization method, as well as tartar, calcium carbonate,
Extending agents such as glass, mica, inorganic fillers such as carbon black, or coloring agents may be added.

The hardness of the thermoplastic elastomer composition (JIS-6
The reason for limiting the hardness to 301) is that if the hardness is less than 30, not only will the infusion leak after the inserted injection needle is removed, but the appearance of the product will deteriorate and the mechanical strength will also decrease. . On the other hand, if the hardness of the composition exceeds 60, it will not only be difficult to insert a syringe needle into the composition, but also cause leakage of the infusion after the syringe needle is removed. A stopper for infusion is manufactured from such a thermoplastic elastomer composition by a conventional molding method, but the stopper may be composed entirely of the composition, or may be formed by laminating or combining parts. A portion of the composition may be made up of the composition.

[Embodiments of the invention]

Examples of the present invention will be described in detail below.

Examples 1 to 4 Components (a) to (C) in the proportions shown in the table below were mixed and homogenized using a Henshil mixer at room temperature for 5 minutes, and then kneaded using a twin screw extruder at 200°C and 22 Orpm. . Subsequently, these kneaded materials were put into a stopper prototype mold and molded to produce nine types of stopper stoppers (Examples 1 to 4 and Comparative Examples 1 to 5) each having a wall thickness of 5 m.

For each stopper obtained, physical properties such as hardness, tensile strength, tensile elongation, and compression set were determined, as well as stopper characteristics such as liquid leakage after needle removal, coring, medical hygiene, and appearance of the molded product. , and heat resistance were investigated. The results are also listed in the same table. The physical properties and stopper properties were measured by the following methods.

■Hardness: Components (a) to (C) in the proportions shown in the table below are mixed and homogenized using a Henshil mixer at room temperature for 5 minutes, then kneaded using a twin-screw extruder at 200°C and 220 rpm. The mixed wire is injection molded under 200℃ condition to make 2tr.
A sheet with a thickness of
The hardness was measured according to 01.

(2) Tensile strength: The tensile strength of the sample was measured according to JIS-6301.

(2) Tensile elongation: The tensile elongation of the sample was measured according to JIS-6301.

(2) Compression set: The compression set of the sample was measured at 70°C for 22 hours according to JIS-6301.

■Fluid leakage after needle removal: After inserting a commercially available infusion set and double-ended needle (plastic needle or stainless steel needle) into the stopper, leakage of infusion liquid was measured when the needle was removed one hour later. .

(2) Coring: Generation of plum waste when inserting or removing a needle (12-21G) from a stopper was measured.

■Medical hygiene: Measured in accordance with the Japanese Pharmacopoeia 10th revision rubber stopper test method for infusions and plastic container test method for infusions.

■Appearance of molded product: The presence or absence of weld lines, delamination, and flow marks on the injection molded product was measured, and the quality of the appearance was determined based on these.

(2) Heat resistance: The presence or absence of deformation was measured when the stopcock was steam sterilized at 121° C. for 50 minutes.

As is clear from the above table, the infusion stopper of the present invention, which is made of a specific thermoplastic elastomer and has a hardness of 30 to 60, has very excellent properties.

〔Effect of the invention〕

As detailed above, according to the present invention, residual solvents, additives, etc. do not elute over time, moldability is good, cleaning treatment after molding is not required, and furthermore, a syringe needle can be easily inserted, and injection It is possible to provide an easy-to-manufacture stopper for infusion that can prevent occurrence of coring phenomenon during needle insertion and withdrawal, leakage of infusion after withdrawal, etc.

Claims (1)

Scope of Claims: (a) General formula A-(B-A)n (However, A in the formula is a polymer block consisting of a monovinyl-substituted aromatic hydrocarbon and having a molecular weight of 15,000 to 60,000, and B is a conjugated Molecule weight 6 made of diene elastomer
0000 to 180000 polymer blocks, n is 1 to 5
indicates an integer. ] 100 parts by weight of a hydrogenated derivative of a copolymer represented by; (b) 100 to 185 parts by weight of a softener for paraffinic rubber; (c) 20 to 60 parts by weight of a crystalline propylene polymer resin; and the hardness (JIS-K6301) is 30-6
1. A stopper for infusion, characterized in that it is partially or entirely composed of a thermoplastic elastomer composition of No. 0.