JPS58159759A - Production of inner cylinder of disposable syringe - 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 The present invention relates to a method for manufacturing a disposable syringe inner barrel, and more particularly to a method for simultaneously molding and fixing a steril to the tip of an insertion rod of a disposable syringe inner barrel.

Syringes used for medical purposes have traditionally been made of glass.

In addition, disposable syringes mainly made of plastic materials are now widely used and have become mainstream due to their ease of use and to prevent medical accidents due to reuse of syringes such as serum hepatitis contamination.

This disposable syringe, as shown in Figure 1,
It can be roughly divided into an outer cylinder α and an inner cylinder α. The inner cylinder usually has an insert which is a support and the insert!, as shown in FIG. P: Consists of a protrusion d which is fitted on the tip end face of C. The syringe is used to maintain liquid tightness with the inner surface of the outer cylinder during injection and suction operations of the syringe, and is made of an elastic material such as rubber, plastic, or plastic. Two protrusions f and f' are protruded from the root portion in a ring shape and have an outer diameter such that they come into sliding contact with the inner surface of the outer cylinder α.

The method for manufacturing the disposable syringe inner barrel is as follows:
Conventionally, Naruko shown in Fig. 3A and insertion rod C shown in Fig. 3B were used.
are formed separately in advance, and then the protrusion d of the insertion box C is press-fitted into the concave portion d of the cross-sectional shape A (corresponding to the protrusion d of the insertion rod C) to form the insertion box. A method of assembling C and Seiko 6 has been adopted.

However, in such a method, the insertion box C and Naruko-
The insertion box C is assembled by press-fitting and fitting.
The protrusion d and the concave part of Nariko! A high degree of precision is required in the dimensions and shape of the fitting part. In addition, the film thickness of Nariko e is necessary compared to the film thickness required for liquid tightness with the original inner surface of the outer cylinder, in order to ensure that the required fitting strength with protrusion d of insertion box C is maintained. As a result, the above materials are used, resulting in a waste of both materials and costs. Generally, the material used for the child is required to have elasticity and is therefore more expensive than the material for the insertion box. Therefore, it is necessary to minimize the use of such materials. Furthermore, since an elastic material is used for the suction part, the molding methods are limited. Conventionally, as shown in Figure 4A, several to several dozen suction parts were molded onto a single elastic plate. After that, the process of cutting the product as shown in Figure 4B (
The method is sloppy in terms of picking), and a large amount of unnecessary parts of the elastic material is generated, which poses problems in terms of productivity and economy.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to stably, reliably, and productively fix the insertion box and the insertion box, and to speed up the assembly process of the insertion box and the insertion box. It is an object of the present invention to provide a method for manufacturing a disposable syringe inner cylinder at a low cost and efficiency, thereby preventing contamination within the syringe, reducing the use of sterilizing materials, and thus producing a disposable syringe inner cylinder at low cost and efficiency.

In the method according to the present invention, a so-called insert molding method is used to simultaneously form and fix a child to the tip of an insertion rod.

Hereinafter, the method of the present invention will be explained with reference to the accompanying drawings.

FIG. 5 shows an embodiment of the mold used in the method of the present invention, including a mold 10 and a mold cavity 2.
The mold includes a cylindrical insertion hole 3 into which the insertion box is inserted, a digging part 4 with a predetermined cross-sectional shape that defines the outer surface of the seedling, and a raw material injection port 5 communicating with the nucleus insertion part 4. The cavity 2 itself is a through hole.

As shown in FIG. 6, the insertion box 6 is first inserted into the mold cavity 2 of the molding mold 1 through the insertion hole 3, and the protrusion 7 at the tip of the insertion box 6 is inserted into the mold cavity 2. After placing the insertion part 4 in a predetermined position and fixing the head of the insertion box 6 with the fixed foot plate 9, fluidity at room temperature is injected from the tip 10 of the injection machine that is in contact with the raw material injection port 5 of the molding die 1. Inject rubber or plastic raw materials with After filling the raw material into the recessed part 4 of the molding die 1, the molding die is heated to heat and harden the raw material, and then the insertion box 6 is released from the molding die 1, and the protrusion at the tip of the insertion box is removed. A syringe inner barrel is obtained in which the child 7 is attached to the child.

As is clear from FIG. 6, as long as the insert a$6 can be firmly fixed, the insertion hole 30 portion of the mold cavity 2 is unnecessary, and even the digging portion 4 and the raw material injection port 5 communicating therewith are not necessary. If provided, insert molding according to the present invention is possible.

Alternatively, it can also be injected through the opening at the top of the digging part.

In addition to the means for fixing the head of the insertion box 6 using a fixing plate, it is of course possible to use other fixing means having a gripping or clamping action.

In the method of the present invention, rubber or plastic, etc., which is fluid at room temperature and hardens by heating, can be used as the raw material for filling the molding die 1 into the trench 4, but the softening of the insertion box below the point, preferably +300C
Those that harden at a certain heating temperature can be suitably used. Among them, silicone rubber is especially advantageous in terms of safety because it has extremely low leaching (extraction), ie, migration into the chemical liquid, when it comes into contact with the chemical liquid. The heating and forming temperature can be appropriately set at a temperature below its softening point, depending on the type of raw material for the raw material.

In addition, since the raw material for sterilization used in the present invention has fluidity at room temperature, it can be filled at low pressure.

Therefore, as shown in FIG. 6, if the inner diameter of the insertion hole 3 of the molding die 1 is designed to be just slightly larger than the outer diameter of the protrusion side flange 8 of the insertion rod 6, most An appropriate amount of material can be injected without producing excess material. Furthermore, even if there is a slight gap between the outer diameter of the protrusion side flange 8 and the inner diameter of the insertion hole 3 of the mold, for example, as shown in FIG.
By protruding the ridge 11 on the inner surface of the insertion opening of the molding die facing the protrusion side flange 8, a cutout can be formed in advance during molding, and a cutting process for excess material is not necessary, and the excess material can simply be removed. You can remove the twigs just by pulling.

FIG. 8 shows a cross-sectional view of a disposable syringe inner cylinder manufactured using a molding die and insertion rod having the cross-sectional shape shown in FIG. A cross-sectional view of the manufactured disposable syringe inner cylinder is shown in FIG. As is clear from FIGS. 8 and 9, according to the insert molding method according to the present invention, the insertion rod 6.61
Except for the thin film portion covering the protrusion 7, the elastic material is
Most of the suction rings +3 and +3' are used to maintain liquid tightness between the fixing part 2 and the inner surface of the outer cylinder, and expensive elastic materials can be used efficiently. Furthermore, in order to secure the fixation of the sucker 12, it is necessary to provide a groove-like notch 14 at the base of the protrusion of the insertion tube, but in the disposable syringe inner cylinder shown in FIG. 3
, + 3' notches directly below + 4 , + 4
Since the structure has ', the suction ring +3, +
There is an advantage that the elastic portion 3' can be made large, and that the adhesiveness to the insertion tube 6' and the liquid-tight effect with the inner surface of the outer cylinder can be improved. Incidentally, it is of course possible to arbitrarily design the cross-sectional shapes of the projections 7 and suckers 12 of the insertion rods 6, 6'.

The insertion rod can be released from the molding die by applying a little force to pull up the insertion rod, since the suction rod after being heated and hardened is an elastic body. A split mold can be used as a method for easy release, but the split mold is unfavorable in terms of appearance because it creates streaks along the split lines.

It can also be achieved by performing the above steps continuously. For example, the steps of inserting and fixing an insertion rod into a mold placed on a conveying device, injecting raw materials, heating and curing, and releasing the mold are successively performed.
Disposable syringe inner cylinders with suckers attached to the protrusions at the tip of the insertion rod can be manufactured continuously. As the heating means, any heating device such as a flame infrared heater, a hot air stove, or another electric furnace can be used.

FIG. 10 shows an example of a mechanism for supplying raw materials to a mold. A raw material tank 15 stores rubber or plastic raw materials that are fluid at room temperature.
An appropriate amount is measured in the measuring cylinder 17 and supplied to the injection machine 1g, and from the injection machine 18, air is removed from the raw material by the depressurization cylinder 20 connected to the injection @ 18. It is injected into the mold 1 from the tip 19 of the injection machine.

As described above, according to the method for manufacturing a disposable syringe inner cylinder according to the present invention, the molding of the sucker and the fixing to the tip of the insertion rod are performed at the same time, so that the molding accuracy and the adhesion strength between the sucker and the insertion rod are improved, There is less generation of unnecessary parts of elastic material, and elastic material can be efficiently used in the ring part of the sucker, which requires elasticity. Also, like the conventional method,
By using post-processing (cutting process) after molding, a disposable syringe inner barrel can be manufactured at a very low cost, and the process of assembling the sucker and insertion rod can be omitted.
Contamination inside the syringe can be prevented. Furthermore, by using silicone rubber as the elastic material, there is a further advantage that the safety of the syringe can be improved because its migration to the drug solution is extremely small.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a disposable syringe, and Figure 2 is a clear diagram.
The figure is a sectional view of a conventional disposable syringe inner barrel, Figure 3A is a sectional view of a conventional sucker, Figure 3B is a plan view of a conventional insertion rod, and Figure 4A is a conventional molded sucker. A perspective view showing the state, No. 4 rylB is an explanatory diagram of the cutting process of the forming element shown in FIG. 4A, FIG. FIG. 7 is a partial sectional view of the state in which the insertion rod is inserted into the mold, and FIG. 8 and FIG. FIG. 2 is a cross-sectional view of a disposable syringe inner barrel manufactured using a molding die having the cross-sectional shape shown in the figure and insertion technology. FIG. 10 is a schematic explanatory diagram showing an example of a mechanism for supplying raw materials to a molding die. 1 is a molding die, 2 is a mold cavity, 4 is a digging part,
5 is a raw material supply port, 6.6' is an insertion rod, 7 is a protrusion; 2 is a child. Applicant Nippon Medical Sagrai Co., Ltd. Agent Patent Attorney Masaaki Hara Patent Attorney Tadashi Hon Figure 1 Figure 3 (A) [B) Figure 4 [AI Figure 5 Figure 10 Figure 7 ♂

Claims (1)

[Claims] A molding die having a recessed part 4 with a cross-sectional shape corresponding to the outer surface of Naruko 12! , and insert the rod 6 into the above-mentioned recessed part 4.
A thermosetting elastic material having fluidity at room temperature is filled with the protrusion 7 at the tip arranged, the elastic material is then heated and hardened, and then the insertion rod 6 is released from the molding die 1. A method for manufacturing a disposable syringe inner barrel.