JPH0666689U - Syringe - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a syringe having a gasket that can be economically laminated with a thermoplastic film in one molding and that satisfies both airtightness and slidability between an inner wall of a syringe barrel and a gasket. In a syringe 40 made by fitting a gasket 10 connected to the tip of a plunger 42 into an injection cylinder 41, a chemical solution is pressurized as the plunger 42 is pushed, and a reaction surface pressure of the chemical solution causes a concave chemical solution contact surface 18 Receives pressure and becomes flatter and expands to the circular edge side, the contact pressure on the inner peripheral surface of the injection cylinder in the first crest portion 13 increases, the airtightness is improved, and the liquid medicine is discharged after the first crest portion 13. Since the thermoplastic resin film 17 having excellent chemical resistance is laminated and laminated only on the chemical solution contact surface 18 without invading, there is no migration into the chemical solution, and the sliding property is maintained while maintaining excellent airtightness. A very light pushing operation is possible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to the improvement of the stopper of the sliding part of the plunger used in disposable syringes, prefilled syringes, etc., in which the contact surface side with the drug solution has a concave shape whose diameter increases due to the back pressure of the drug solution, and Laminated thermoplastic resin film with excellent chemical resistance that has few migration products into the chemical solution is laminated on the contact surface with the chemical solution, and a plunger slide with no migration products, good airtightness and good sliding property. The present invention relates to a syringe having a gasket structure of the part.

[0002]

[Prior art]

 Disposable disposable injectors with gaskets (sliding plugs, suckers) for airtightness between glass or plastic syringes and plungers (push rods), and more recently simplified treatment In order to prevent errors and contamination, a syringe called a prefilled syringe, which is also used as a container and filled with a drug solution in the manufacturing process, is often used.

The gasket of the above-mentioned syringe is made of a molded product such as vulcanized rubber or elastic plastic, but it does not leak the drug solution by airtightly fitting with the inner wall of the injection cylinder, and the plunger can be pushed in or pulled out. Dynamic movement requires simple and light sliding properties. These required characteristics are described in “Ministry of Health and Welfare Notification No. 412 Disposable Syringe Standard”, “Regarding the force required to move the plunger (sucker movement test), the sucker must move smoothly inside the outer cylinder. Also, in this case, there must be no gum pieces of the sucker remaining in the cylinder. "

In order to satisfy such required characteristics, since the advent of disposable syringes, as a conventional technique, silicone oil has been applied to the surface of a gasket to maintain airtightness and lubricate with a syringe barrel. However, such an injector has a risk that silicone oil may drop into the drug solution during use and be injected into the human body together with the drug solution. In recent years, countermeasures for removing fine particles from injectables have been promoted, and it has been desired to prevent contamination of fine particles caused by container devices.

[0005]

[Problems to be solved by the device]

 Rubber gasket materials used in disposable syringes and prefilled syringes contain rubber vulcanizing agents, vulcanization accelerators, plasticizers, etc., which may cause various inappropriate substances and foreign substances to migrate into the chemical solution. . If the surface of the rubber gasket is covered with a film of non-migrating fluororesin, PP, PE, etc., a barrier effect can be expected on the contact surface with the chemical solution, but the surface is harder and less elastic than the rubber material. Therefore, airtightness with the inner surface of the syringe may be deteriorated and leakage may occur. As shown in FIG. 6, in the syringe 1 using the conventional gasket 4, the airtightness and slidability between the syringe barrel 2 and the gasket 4 of the plunger 3 are greatly affected by the strength of the fitting. It was easy.

Therefore, although the hardness and thickness of the film laminated and laminated on the gasket are adjusted (Japanese Utility Model Laid-Open No. 62-139668), as shown in FIG. 7, the sliding portion (outer diameter portion) of the gasket 5 is formed. The number of annular projections 6 is increased and the resin film 7 is laminated and laminated (Publication No. 1-138455), and the ratio of the diameter to the length of the gasket is limited (Publication No. 1-138454). Etc. have been proposed. However, the airtightness and slidability between the gasket and the syringe are contradictory requirements, and there is a problem that the slidability decreases with increasing airtightness. Further, as shown in FIG. 8, a method of laminating the resin film 9 only on the first mountain in order to achieve both the sealing property and the sliding property of the gasket 8 is also proposed (Japanese Utility Model Publication No. 52-19435, Japanese Utility Model Publication 55-55-). 30602 publication). However, since the technology of laminating the entire first peak of the annular protrusion and forming the end of the film in the valley is complicated and the manufacturing cost increases, a gasket having such a structure has not yet been commercialized.

[0007] As described above, this invention is eclectic in the existing technology because it is not sufficient to satisfy both the airtightness and the slidability between the inner wall of the syringe barrel and the gasket in the gasket in which the resin is laminated and laminated. In view of the fact that basic problems have not been solved, such as the need for special selection of materials, etc., these problems have been resolved, and thermoplastic film lamination has been completed economically in one molding, It is an object of the present invention to provide a syringe having a gasket that satisfies all barrier properties, airtightness, and slidability.

[0008]

[Means for Solving the Problems]

 The inventors have conducted various studies, focusing on the shape of the contact surface of the gasket with the chemical solution, for the purpose of producing a syringe having a gasket that has good manufacturability, barrier properties, airtightness, and slidability. The contact surface with the chemical solution is made into a dish-shaped concave shape, and by laminating and laminating a specific thermoplastic resin film only on the same part, by back pressure of the content chemical solution when pushing the gasket while maintaining the barrier property. The diameter increases and the airtightness is improved by the valve effect, and the elastic rubber material is exposed on the contact surface of the gasket with the inner peripheral surface of the injection cylinder, so sufficient airtightness is achieved without increasing the gasket diameter. We have found that we can obtain smoothness and have completed this invention.

That is, in the present invention, in a syringe in which a gasket is pushed into a syringe barrel by a plunger and can be pulled out, the diameter can be increased by back pressure of the content drug solution when the contact surface side of the gasket with the drug solution is pressed. The syringe is characterized in that the thermoplastic resin film having excellent chemical resistance and having few substances transferred into the chemical liquid is laminated and laminated on the concave portion of the gasket. The invention is also a syringe characterized in that, in the above-mentioned constitution, a contact surface with a drug solution obtained by laminating and laminating a thermoplastic resin film makes an acute angle contact with an inner peripheral surface of an injection cylinder.

In the present invention, the syringe can be applied to any structure as long as it is a disposable syringe, a prefilled syringe, or the like in which a gasket is pushed by a plunger by a plunger and can be pulled out. Further, in this invention, the gasket is made of natural rubber, IIR, IR, SiR, UR soft vulcanized rubber, or a thermostable material such as TPE or SEBS that has a high elasticity and withstands sterilization temperature of about 60 ° C or more and γ ray sterilization. The elastomer can be appropriately selected. Further, as the thermoplastic resin film to be laminated and laminated, a soft plastic film such as fluororesin, PE or PP can be appropriately selected, and the film thickness is preferably 0.01 to 0.1 mm in order to maintain elasticity.

[0011]

[Action]

 The operation of the syringe according to the present invention will be described in detail with reference to the drawings. 3 and 4 are longitudinal explanatory views showing the structure of the gasket according to this idea. The gasket 10 shown in FIG. 3 is composed of a cylindrical body having a required diameter and length, and by providing two annular groove portions 11 and 12 on the outer peripheral surface, three peak portions 13, 14, 15 are formed on the outer peripheral surface. Has been formed. It is preferable that the number of annular grooves is two or more and the number of ridges is three or more. Further, in the figure, a right side end surface is formed with a fitting hole 16 for making a fitting connection with the tip of the plunger, a left side end surface is formed into a concave surface, and a thermoplastic resin film 17 is laminated and laminated. The contact surface 18. The chemical solution contact surface 18 of the gasket 10 is formed as a so-called dish-shaped concave surface having a flat central portion and a slanted periphery, and the thermoplastic resin film 17 is laminated on the chemical solution contact surface only. The portion is in contact with the inner peripheral surface 2a of the injection cylinder at an acute angle.

When the gasket 10 is pushed leftward by a plunger (not shown), the chemical liquid is pressurized, and the reaction pressure of the gasket 10 causes the concave chemical liquid contact surface 18 to receive a pressure and become more flat, and expand to the circular edge side. In other words, since the diameter changes valve-wise and the circumference is enlarged, the contact pressure on the inner peripheral surface 2a of the syringe barrel in the first crest portion 13 is increased, the airtightness is improved, and the liquid medicine is in the first crest portion. It will not invade after 13. Therefore, since the diameter of the liquid contact surface 18 of the gasket 10 changes like a valve due to pressure reception and the airtightness is maintained, it is unnecessary to make the peaks 13, 14, 15 excessively large, and On the other hand, if the diameter is expanded by about 0.05% to 2%, airtightness and slidability are satisfied. The annular groove portions 11 and 12 have a groove structure for promoting the elasticity of the ridge portions 13, 14 and 15, and the diameters of the ridge portions are preferably 0.5 to 2 mm. Further, the axial width of the first mountain portion 13 is preferably 0.5 to 2 mm in order to maintain elasticity. On the other hand, in the case of the conventional gasket 4 shown in FIG. 6, the chemical contact surface is a convex surface and is in contact with the inner peripheral surface 2a of the injection cylinder at an obtuse angle, and the outermost edge portion is contracted by the pressure applied to the convex surface that receives the pressure. The shape is such that the airtightness is reduced by pushing the plunger.

The gasket 20 shown in FIG. 4 has the same configuration as that of the gasket 10 shown in FIG. 3, except that the central portion of the chemical liquid contact surface 21 formed on a so-called dish-shaped concave surface is slightly convex. The outermost edge of the drug solution contact surface 21 makes an acute contact with the inner peripheral surface 2a of the injection cylinder into which it is inserted, and the above-described effects are achieved. In the examples of FIGS. 3 and 4, the outermost edges of the chemical liquid contact surfaces 18 and 21 are in contact with the inner peripheral surface 2a of the injection cylinder at an acute angle, but when receiving pressure, The contact angle may be appropriately selected as long as the contact pressure with respect to the inner peripheral surface 2a of the syringe is equal to or less than a right angle.

[0014]

【Example】

 Example 1 In order to manufacture the above-mentioned gasket shown in FIG. 3, as shown in the cross-sectional explanatory view of the rubber mold of FIG. 5, the soft rubber 32 is put in the cavity 31 of the required shape formed in the lower mold 30, A resin film 33 made of fluororesin, PP, PE or the like is placed on the upper side with the surface subjected to physical treatment such as corona and spattering on the rubber side, and the upper mold 34 is overlaid and heated by a usual compression molding method. By vulcanizing and laminating and adhering, and after vulcanizing, by removing the excess rubber ballit film according to the gasket outer diameter by punching, it was possible to easily manufacture by one molding. A disposable syringe was prepared using the obtained gasket. As shown in FIG. 1, the gasket 40 of FIG. 3 connected to the tip of the plunger 42 was fitted into the syringe barrel 41 to prepare the syringe 40. Comparing the slipperiness of the gasket of the conventional syringe 1 of FIG. 6 with the syringe 40 of the present invention, it was found that the present invention was capable of extremely light pushing operation while maintaining excellent airtightness.

Example 2 A prefilled syringe was produced using the gasket obtained in Example 1. That is, as shown in FIG. 2, the chemical solution 55 is stored in an inner container 53 whose tip is sealed with a rubber stopper 54 and whose other end is open, and the gasket 10 connected to the tip of the plunger 56 is placed inside the inner container 53. The inner container 53 was inserted into an injection cylinder 51 equipped with a double-edged pricking needle 52 to form a prefilled syringe 50. The gasket 10 has a chemical contact surface that changes in valve-like diameter due to the pressure received when the stored chemical is sealed and maintains airtightness, and is a thermoplastic resin with excellent chemical resistance with little migration into the chemical. Since the films are laminated and laminated, the stored chemical liquid 55 in the inner container 53 can be protected from contamination over a long period of time. When the plunger 56 is pushed during use, the inner container 53 first moves inside the injection cylinder 51, the rubber plug 54 is pierced by the inner blade of the puncture needle 52, and the plunger 56 is pushed further. The gasket 10 moves, and extremely light pushing operation is possible while maintaining excellent airtightness.

[0016]

[Effect of device]

 The syringe according to the present invention has a dish-shaped concave surface on the gasket that contacts the liquid medicine, and by laminating and laminating a specific thermoplastic resin film only on the same part, when the gasket is pushed in while maintaining the barrier properties. The back pressure of the drug solution expands its diameter to improve airtightness, and the gasket material is exposed at the contact surface of the gasket with the inner peripheral surface of the injection cylinder, providing sufficient sliding properties and manufacturing. It is suitable for not only disposable syringes but also prefilled syringes because it has good properties and satisfies all barrier properties, airtightness and slidability.

[Brief description of drawings]

FIG. 1 is a vertical cross sectional view showing the structure of a disposable syringe according to the present invention.

FIG. 2 is a vertical cross sectional view showing the structure of a prefilled syringe according to the present invention.

FIG. 3 is a vertical cross sectional view showing a structure of a gasket according to the present invention.

FIG. 4 is a vertical cross sectional view showing another structure of the gasket according to the present invention.

FIG. 5 is an explanatory cross-sectional view of a rubber mold for manufacturing a gasket according to the present invention.

FIG. 6 is a vertical cross-sectional explanatory view showing the configuration of a conventional disposable syringe.

FIG. 7 is a vertical cross sectional view showing the structure of a conventional gasket.

FIG. 8 is a vertical cross-sectional explanatory view showing another configuration of the conventional gasket.

[Explanation of symbols]

 1 Syringe 2 Injection Cylinder 2a Injection Cylinder Inner Surface 3 Plunger 4,5,8 Gasket 6 Annular Protrusion 7,9 Resin Film 10,20 Gasket 11,12 Annular Groove 13,14,15 Crest 16 Fitting Hole 17 Heat Plastic resin film 18,21 Chemical contact surface 30 Lower mold 31 Cavity 32 Soft rubber 33 Fluororesin film 34 Upper mold 40 Syringe 41,51 Syringe 42,56 Plunger 50 Prefilled syringe 52 Needle 53 Inner container 54 Rubber stopper 55 Liquid medicine

Claims (2)

[Scope of utility model registration request] 1. A syringe in which a gasket is pushed into a syringe barrel by a plunger so that the syringe can be pulled out, and when the contact surface side of the gasket with the chemical liquid is pushed, the concave shape is formed so that the diameter can be expanded by the back pressure of the chemical liquid. A syringe characterized by laminating and laminating a thermoplastic resin film having excellent chemical resistance with less migration into the chemical liquid on the concave portion of the gasket. 2. The syringe according to claim 1, wherein a contact surface with a drug solution obtained by laminating and laminating a thermoplastic resin film is in contact with the inner peripheral surface of the injection cylinder at an acute angle.