JP2001190667A - Gasket for syringe and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new gasket which shows an improved sliding property and airtightness and causes no problem concerning the contamination of the drug nor the generation of laminated film fragments. SOLUTION: The gasket comprises a distal, first molded part 1 containing a drug-contact surface 11 and a first cyclic sliding surface 12 which is adjacent to this, and a proximal, second molded parts 2 containing a plurality of cyclic sliding surfaces 21 and 22 formed by insert molding of the first molded part 1. The lateral surface containing the drug-contact surface 1 and the first cyclic sliding surface 12 of the first molded part 1 is laminated with a synthetic resin film, and the end surface 13 of the film laminated on the lateral surface of the first molded part 1 is implanted in the second molded part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gasket for a syringe and a method for manufacturing the same. The gasket of the present invention
Both slidability and airtightness can be satisfied.

[0002]

2. Description of the Related Art Conventionally, a gasket for a syringe is prepared by mixing a natural rubber, an isoprene rubber, a styrene / butadiene rubber, a butadiene rubber, etc. with a vulcanizing agent, a vulcanization accelerator, a reinforcing agent and the like in a mold. It was formed by vulcanization. In recent years, a thermoplastic elastomer such as a styrene-butadiene copolymer has been used as a material for forming a gasket. By the way, gaskets formed from these rubber elastic materials contain a water-soluble substance, and there is a problem in that the chemical liquid is contaminated by this substance. Therefore,
In order to prevent contamination of the chemical solution and to improve the slidability of the gasket, various proposals have been made for a so-called laminated gasket in which the surface of the gasket is laminated with a film of a fluorine-based resin or an olefin-based resin. −
19435, JP-A-2-152463, etc.).

[0003] However, laminated gaskets are
Although the problem of chemical contamination and the slidability are improved, there is a problem that airtightness is reduced. If the airtightness between the gasket and the syringe barrel is reduced, there is a risk of so-called leakage, in which the chemical solution leaks outside when the gasket is moved. Also,
Since the end of the laminated film exists on the surface of the gasket, fragments of the film may be generated in the process of assembling the syringe, and may be mixed as foreign substances into the chemical solution. Furthermore, in the case of a so-called pre-filled syringe pre-filled with a drug solution, there is a possibility that the drug solution contained therein may be deteriorated during storage.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and has no problem of contamination of a chemical solution, of course, does not generate fragments of a laminated film, and has good slidability. It is an object of the present invention to provide a novel gasket having improved airtightness.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have formed a gasket with a first molded portion on the distal end side laminated with a chemical resistant synthetic resin film, By forming the second molded portion on the base end side which is not laminated and insert-molding the first molded portion formed earlier to form the second molded portion, the cut surface of the burr portion of the laminated film is reduced. Having conceived that it can be prevented from being exposed on the surface of the rubber, the present invention has been completed. That is, the present invention (the first invention) is a sliding member made of a rubber elastic material which slides in close contact with the inner wall of the syringe outer cylinder, and comprises a chemical contact surface and a first annular sliding surface adjacent thereto. A first molded portion on the distal end side and a second molded portion on the proximal end side including a plurality of annular sliding surfaces formed by insert molding of the first molded portion, and the chemical contact surface of the first molded portion. And a side face laminated with a chemical-resistant synthetic resin film, and an end face of the film laminated on the side face of the first molded part is buried in the second molded part. Here, the synthetic resin which is a material for forming the film is preferably selected from the group consisting of a fluororesin, an ultrahigh molecular weight polyethylene resin, and a polypropylene resin, particularly preferably an ultrahigh molecular weight polyethylene resin.

In the present invention (second invention), an unvulcanized rubber and a chemical resistant synthetic resin film for lamination are stacked, placed in a molding die, and vulcanized and molded to form a first molded portion. . Take out the first molded part and cut off the burr part. The first molding portion from which the burr portion has been removed is put into a molding die with the burr portion cut surface facing upward, and the mold is clamped.
A second molded part is formed by injecting and vulcanizing rubber from above the clamped first molded part. Take out the molded product, 2nd
Cut and remove the burr of the molded part. A method for manufacturing a gasket for a syringe, comprising the steps of: Here, the synthetic resin which is a material for forming the film is preferably selected from the group consisting of a fluororesin, an ultrahigh molecular weight polyethylene resin, and a polypropylene resin, particularly preferably an ultrahigh molecular weight polyethylene resin.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing one embodiment of the gasket of the present invention, and FIG. 2 is an explanatory diagram for explaining a method of manufacturing the gasket of the present invention. As shown in FIG.
The gasket of the present invention has a first molded portion 1 on the distal end side including a chemical solution contact surface 11 and a first annular sliding surface 12 adjacent thereto.
The second molding portion 2 on the base end side including the plurality of annular sliding surfaces 21 and 22 formed by insert molding of the first molding portion 1.
Consists of Then, the chemical liquid contact surface 1 of the first molding portion 1
1 and the side surface including the first annular sliding surface 12 are laminated with a chemical-resistant synthetic resin film F, and the end surface 13 of the film F laminated on the side surface of the first molded portion 1 is formed on the second molded portion 2. Buried

The gasket according to the present invention is a sliding member made of a rubber elastic material which slides in close contact with the inner wall of a syringe barrel (not shown), and comprises a first molding portion 1 on the distal end side and a proximal end. The second molded part 2 on the side. The first molded part 1 includes a chemical contact surface 11 and a first annular sliding surface 12 adjacent thereto, and a chemical contact surface 11 and a first annular sliding surface 12 at the tip.
Is laminated with the chemical-resistant synthetic resin film F, and the end surface 13 of the film F laminated on the side surface of the first molded portion 1, that is, the cut surface when the burr portion 13 of the first molded portion 1 is cut. 13 is buried in the second molded part 2 formed by insert molding (in other words, the part including the cut surface 13 is wrapped in the second molded part 2). ). As a synthetic resin that is a material for forming a laminate film, a group consisting of a polytetrafluoroethylene having a chemical resistance, a fluororesin such as an ethylene-tetrafluoroethylene copolymer, an ultrahigh molecular weight polyethylene resin, and a polypropylene resin. Is preferable, and an ultrahigh molecular weight polyethylene resin is particularly preferable. The thickness of the laminate film is usually 0.05 to 0.2 mm.

The second molded portion 2 is a portion formed by insert molding of the first molded portion 1 and includes a plurality of annular sliding surfaces (in the figure, a second annular sliding surface 21 and a third annular sliding surface 22). Are provided). The second molded portion 2 is hollow, and a coupling means for coupling a plunger (not shown) to the gasket, for example, a female screw 23 is provided on the inner wall thereof.

The gasket of the present invention is slidably inserted into a barrel (not shown), and a plunger (not shown) is connected to a coupling means of the second molded portion 2, for example, a female screw 23. Used as a syringe. Since the gasket of the present invention is formed of a chemical-resistant synthetic resin film in which the contact surface with the chemical solution is laminated,
It is suitable for a prefilled syringe in which a drug solution is stored for a long time. Here, as the drug solution that can be filled in the prefilled syringe, a solution or dispersion solution applicable to the human body or animal, for example, water for injection, physiological saline, Ringer's solution, glucose solution, high calorie infusion, dissolved or dispersed contrast agent Although a liquid etc. can be mentioned, it is not necessarily limited to these.

Next, a method of manufacturing the gasket of the present invention will be described. First, the unvulcanized rubber and the laminating film F are stacked and placed in a molding die, and vulcanized and molded to form the first molded portion 1 (a and b in FIG. 2). As unvulcanized rubber, natural rubber, polyisoprene, polybutadiene, styrene-butadiene rubber, ethylene-propylene rubber,
Butyl rubber or the like is used. Next, the first molded part 1 is taken out (c in FIG. 2), the burr part 14 is cut and removed (d in FIG. 2), and the first molded part 1 from which the burr part 14 has been removed is removed.
The burr cut surface 13 (the surface opposite to the chemical solution contact surface 11) is placed in a molding die with the surface facing upward, and the mold is clamped (e in FIG. 2).
f). As the molding die, a transfer molding die or an injection molding die is employed. Next, the same unvulcanized rubber as the forming material of the first molded portion is injected from above the clamped first molded portion 1 and vulcanized to form the second molded portion 2 (g in FIG. 2). . Finally, the first forming part 1 and the second forming part 2
(H in FIG. 2), and the second molded part 2
The gasket is completed by cutting and removing the burrs 24 (i in FIG. 2).

[0012]

As is apparent from the above description, the gasket of the present invention comprises a first molded portion on the distal end side laminated with a synthetic resin film and a second molded portion on the proximal end side not laminated. Since the second molded portion is formed by insert molding the previously formed first molded portion, the cut surface of the laminated film is inserted into the second molded portion during insert molding. By being buried inside, it is possible to prevent the cut surface of the film from being exposed to the surface of the rubber. Therefore, by adopting the present invention, it is possible to provide a gasket which has no problem of contamination of a chemical solution, does not generate fragments of a laminated film, and has improved slidability and airtightness. Can be.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a gasket of the present invention.

FIG. 2 is an explanatory view illustrating a method of manufacturing a gasket of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st shaping | molding part 11 Chemical liquid contact surface 12 1st annular sliding surface 13 End surface (cut surface) 14 Burr 2 2 2nd shaping | molding 21 2nd annular sliding surface 22 3rd annular sliding surface 23 Female screw 24 Burr F film

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) B29L 31:26 B29L 31:26 (72) Inventor A. Fumi Aramata 3-9-1 Honjo Nishi, Kita-ku, Osaka-shi No. Nissha Corporation (72) Inventor Hiroshi Arifuku 3-9-3 Honjo Nishi, Kita-ku, Osaka-shi F-term in Nissha Corporation (reference) 4C066 BB01 DD08 EE14 HH14 HH17 PP02 4F213 AA45 AC03 AG03 AH13 AH63 WA04 WA05 WA15 WA43 WA52 WA54 WA72 WA87 WB01 WC01 WF06

Claims (6)

[Claims] 1. A sliding member made of a rubber elastic material, which slides in close contact with an inner wall of a syringe outer cylinder, the first member including a chemical solution contact surface and a first annular sliding surface adjacent thereto. A molding part,
A second molding portion on the base end side including a plurality of annular sliding surfaces formed by insert molding of the first molding portion;
(1) A syringe in which a chemical solution contact surface and a side surface of a molded portion are laminated with a chemical resistant synthetic resin film, and an end surface of the film laminated on a side surface of the first molded portion is buried in the second molded portion. Gasket. 2. The gasket according to claim 1, wherein the synthetic resin is one selected from the group consisting of a fluororesin, an ultrahigh molecular weight polyethylene resin, and a polypropylene resin. 3. The gasket according to claim 2, wherein the synthetic resin is an ultrahigh molecular weight polyethylene resin. 4. A method for producing a gasket for a syringe, comprising the following steps: The unvulcanized rubber and the chemical resistant synthetic resin film for lamination are stacked and placed in a molding die, and vulcanized and molded to form a first molded portion. The burr part of the first molding part is cut and removed. The first molding portion from which the burr portion has been removed is put into a molding die with the burr portion cut surface facing upward, and the mold is clamped. A second molded part is formed by injecting and vulcanizing rubber from above the clamped first molded part. The molded product is taken out, and the burr portion of the second molded portion is cut and removed. 5. The method for producing a gasket according to claim 4, wherein the synthetic resin is one selected from the group consisting of a fluororesin, an ultrahigh molecular weight polyethylene resin, and a polypropylene resin. 6. The method according to claim 5, wherein the synthetic resin is an ultrahigh molecular weight polyethylene resin.