JPS61209667A - Syringe excellent in slidability - 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] (Industrial application field) The present invention relates to a syringe with excellent sliding properties and airtightness.

[Conventional technology]

Commonly used syringes are as shown in Figure 1.
It is composed of an outer cylinder 11, a piston 2, and a gasket 3, and the gasket 3 is compressed to maintain airtightness during sliding. Therefore, since sliding resistance is large if left as is, it is usually coated with silicone oil or the like before use.

However, the effect was not sufficient. Also, piston 2
is made of hard resin, while the gasket and rubber mat are made of thermoplastic elastomer, so these must be molded separately and then fitted together. This is one of the factors that makes the manufacturing cost of syringes high. If the gasket could be made of the same material as the piston, it would be possible to achieve a significant cost reduction by integrally molding the two, but this is currently impossible in terms of airtightness and slidability.

(Problems to be Solved by the Invention) An object of the invention is to provide a syringe with excellent slidability and airtightness.Another object of the invention is to provide a syringe with an integrally molded gasket and piston. It is about providing.

[Means and effects for solving the problem] The above purpose is to provide
This is accomplished by chemically bonding water-soluble polymers.

The water-soluble polymer conveniently used in the present invention is a polymer that is water-soluble at room temperature or under heating. Examples of such polymers include acrylamide polymers such as polyacrylamide and polydimethylacrylamide, methacrylamide polymers such as polymethacrylamide, polyvinylpyrrolidone, partially saponified and completely saponified polyvinyl alcohol, and polyethylene glycol. , dextran, polymethyl vinyl ether, starch, polyacrylic acid, polymethacrylic acid, and the like.

These polymers may be homopolymers or copolymers.

A method for chemically bonding the above polymer to the inner surface of the syringe barrel and/or gasket surface is to generate radicals or peroxides on the surface to which the polymer is to be bonded, and then contact the monomer with the radicals or peroxides. There are two methods: a method in which a polymer is allowed to undergo graft polymerization, and a method in which a pre-formed polymer is chemically bonded to the surface. Methods for generating radicals or peroxides include (1) irradiation with energetic radiation such as electron beams and gamma rays, (2) irradiation with ultraviolet rays, (3) low-temperature plasma discharge treatment, and (4) corona discharge treatment. , (5) ozone treatment, and (6) a method of adding a radical polymerization initiator such as benzoyl peroxide. Polymerization is carried out by allowing monomers to coexist when the syringe is subjected to these treatments, or by bringing the monomers into contact with each other after the treatment, and the polymers are chemically bonded. Monomers used include acrylamide, dimethylacrylamide, methacrylamide,
Vinylpyrrolidone, vinyl acetate and ethylene oxide can be mentioned. After polymerization, vinyl acetate is saponified and converted into polyvinyl alcohol.

In the present invention, the barrel and piston of the syringe can be made of polypropylene or polyethylene as in conventional syringes. In addition, the gasket may be made of rubber or thermoplastic resin elastomer as in the past, or
It may be manufactured by integral molding from the same material as the piston.

Then, a water-soluble polymer is chemically bonded to these surfaces. Inner surface and/or gasket surface of syringe barrel mI
When a water-soluble polymer is bonded to the material, the surface becomes slippery in a water-containing state, resulting in a surface with excellent lubricity. As a result, when rubber or thermoplastic resin elastomer is used as the gasket, a syringe with superior sliding properties compared to conventional syringes can be obtained.

In addition, a syringe with good airtightness and slidability can be obtained even when the gasket is made of not an elastic material (polypropylene or polyethylene, which is the same as the piston, and is integrally molded with the piston).

In the present invention, the amount of water-soluble polymer bound to the surface of the syringe is preferably 10 μg/aA or more, and 10 μg/aA or more.
It is particularly preferable that it is 0 μνu or more.

〔Example〕

Example 1 The inner surface of the outer cylinder of a syringe shown in FIG. 1, in which the outer cylinder and piston were made of polypropylene and the gasket was made of natural rubber, was subjected to corona discharge treatment. The treated outer layer was then immersed in a 25% aqueous solution of acrylamide for 70 minutes under a nitrogen gas stream.
Graft polymerization was carried out at C for 60 minutes to bond polyacrylamide to the inner surface of the outer cylinder. After the treatment was completed, the homopolymer was removed by washing with warm water. When a gasket and piston were inserted into the resulting outer cylinder and the piston was moved, it showed better sliding properties than before treatment.

Example 2 A syringe shown in FIG. 2 was produced by integrally molding a 2° piston and a gasket from polypropylene. The inner surface of the outer cylinder and the gasket of this syringe were subjected to corona discharge treatment, and graft polymerization was carried out in the same manner as in Example I to obtain a syringe in which polyacrylamide was bonded to the inner surface of the outer cylinder and the surface of the gasket.

Although this syringe was slightly inferior in airtightness and slidability compared to that of Example 1, there was no problem in using it as a normal syringe.

〔Effect of the invention〕

The syringe of the present invention has good airtightness and slidability between the gasket and the outer cylinder, and is functionally excellent.

Further, since a practical syringe can be manufactured by integrally molding the piston and the gasket, it is possible to obtain a syringe with low manufacturing cost.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view of the syringe of the present invention. Further, FIG. 2 is a partially sectional front view of another embodiment of the present invention. ■, Outer cylinder 2, Piston 3, Gasket

Claims (2)

[Claims] (1) A syringe characterized by having a water-soluble polymer chemically bonded to the inner surface of the syringe barrel and/or the gasket surface. (2) A patent claim in which the water-soluble polymer is one or more polymers selected from the group consisting of acrylamide polymers, methacrylamide polymers, polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, and dextran. The syringe according to item 1.