JPS61287725A - Manufacture of plastic tube needle - Google Patents

Abstract

PURPOSE:To prevent plastic from sticking to a mold and facilitate the manufacture of the needle by a method wherein an extruded plastic tube, under the condition of high temperature, is clamped by molds being cooled strongly, to mold it by elongation into a predetermined thickness. CONSTITUTION:The plastic tube 2 of high temperature, which is extruded out of an extruding machine, is clamped by the clamping molds 4, provided on a tension molding machine 3 and cooled strongly, and the molds 4 are moved with a proper speed synchronizing with the extruding speed of the tube 2. Said tube is elongated by this method and is cooled in a water tank 6, thereafter, is cut into a predetermined length. Elongation is effected by making the moving speed of fore mold 4 faster than the same of the rear side mold. Sticking of the tube to the mold or the collapse of the tube may be eliminated and the tube may be formed into an arbitrary configuration by only changing the kind of mold and the moving speed of the mold. This needle is useful as the outer needle of a detaining needle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a thin-walled plastic tube needle, such as an outer needle for an indwelling needle.

(Prior Art and its Problems) Conventionally, when manufacturing a plastic outer needle for an indwelling needle, the following method has been adopted.

That is, first, a plastic tube extruded from an extruder is transferred on a conveyor, cooled with water, and then stretched to a predetermined thickness using a tension forming machine.Next, the tube is wound up, cut to a predetermined length, and then A jig was inserted into both ends of the tube, and the jig was pulled in opposite directions while heating the tube to form the tube to a target thickness.

However, according to this method, when the tube is clamped with a mold in a tension molding machine, the temperature of the mold is room temperature, so the plastic adheres tightly to the mold, causing the tube to collapse or the mold release properties to be poor. There were problems such as deterioration.

In addition, in the past, after the tube was cooled and cut,
There was also the problem that the work process was complicated because it had to be heated and stretched again.

The present invention was proposed as a result of studies to solve these problems.

(Means for Solving the Problems) The general means of the present invention will be explained with reference to FIGS. 1 to 4. First, in FIG. 1, ■ is a plastic extruder; The hot plastic tube 2 is immediately stretched by the tension forming machine 3. As shown in FIG. 2, this tension molding machine 3 is provided with a pair or plural pairs of lamp molds 4, 4, which can be moved in synchronization with the extrusion speed of the tube 2.

These clamp molds 4, 4 are strongly cooled to, for example, 10° C. or lower. As a means for strong cooling, for example, water cooled to 5° C. or lower by a cooling device is circulated through the molds 4, 4. The plastic tube 2 described above is
When introduced into the tension molding machine 3, the plastic tube 2 is kept at a temperature of 160 to 180°C, and after being clamped by the strong cooling clamp molds 4, 4, it is stretched at an appropriate speed. During this stretching,
It is preferable to increase the moving speed of the front mold 4 in the extrusion direction, or to make the moving speed of the rear mold 4 slower than the forward mold speed.

In the present invention, the plastic tube 2 thus tension-molded is cooled in a water tank 6 via a conveyor 5, and then conveyed to a cutting process by a conveyor 7.

As another method of the present invention, as shown in FIG. 3, Luer type rods 8, 8 are inserted into the plastic tube 2, and the outsides of the rods 8, 8 are clamped with Luer molds 4a, 4a. The rods 8, 8 may be slid along the core 9 and the plastic tube 2 may be stretched in the same manner as described above.

In this way, the inner diameter of the tube is regulated by the core material 9, and the luer rods 8, 8 and the molds 4a, 4a
As a result, the clamp portion of the tube is simultaneously molded into the standard Luer shape.

The tube after forming is as shown in Figure 4.
The central part 10 of the small diameter tube part and the rear end <11 of the rear mold 4a are cut, and the rod 8,
8 and core material 9 are inserted.

The plastic tube 2 may be made of polyvinyl chloride, FEP (4-67) ethylene), etc., but the latter has superior flexibility and transparency as a product, has low puncture resistance, and is biocompatible. Also good.

The core material 9 may be made of stainless steel coated with a fluorocarbon resin, and may be used repeatedly. However, the core material 9 may be made of fluorocarbon resin, engineering plastic such as polycarbonate, polyamide, etc., and is cut at the same time as the plastic tube 2. You can.

(Example) FIGS. 5 and 6 show specific examples of an extruder 1 and a tension molding machine 3 in the present invention.

First, in FIG. 5, reference numeral 1 denotes the extruder described above, and an extrusion die 21 is provided at the tip of the extruder 1 with a flange 22.
3 is connected. A heat-resistant support pipe 24 is disposed in the horizontal die 23, so that the inside of the horizontal die 23 is divided into two in the radial direction, and the inside of the support pipe 24 is formed into a passage for the luer rod 8°8. The outside becomes a passage for the high temperature resin.

A Luer type rod 8.8 slidably attached to the core material 9 is inserted from the rear end of the horizontal die 23 and pushed into the support pipe 24. Further, the molten resin is extruded from the extruder 1, passes through the outer periphery of the support pipe 24 of the horizontal die 23, is formed into a tube shape, and is led out. At this time, the luer rods 8, 8 are inserted into the tube 2, and the positions of the rods 8, 8 are clamped by the clamp mold 4.4 from the outside of the tube 2, and the molds 4, 4 is moved along the core material 9 to stretch the plastic tube 2, and then the plastic tube 2 is cut with a cutter 25.

In this embodiment, a cooling water circulation circuit 2 is provided in each of the molds 4, 4.
6 is connected, and cooling water cooled to 5° C. or lower by a cooling device 20 is circulated through the circuit 26 by a circulation device 27 to cool the clamp mold 4.4.

Note that 28 in the figure is a drive control device for the clamp mold 4.4.

FIG. 6 shows a modification of FIG. 5, in which the insertion positions of the luer rods 8, 8 are carried out in the tension forming machine 3. That is, from the tip of the plastic tube 2 extruded from the extruder 1, the luer rods 8, 8
is inserted, the tube 2 is clamped with the clamp dies 4, 4, cut with the cutter 25, and then stretched with the dies 4.4, or after being stretched, the tube 2 is cut.

FIG. 7 shows details of the water tank 6 and the conveyor 5.7. The plastic tube 2 stretched by the clamp molds 4, 4 is conveyed by the belt conveyor 5, charged into the water tank 6, and cooled. be done. Thereafter, the tube is pulled out by a belt conveyor 6a arranged in the water tank 6, and the central part of the small diameter part of the tube is cut by a cutter 29.Then, the belt conveyor 7 removes the lure type rod 8.8 and the core material 9.
It will be transported to the removal process.

(Effects) According to the present invention described above, the plastic tube in a high temperature state extruded from an extruder is clamped with a strongly cooled mold and tension-molded to a predetermined thickness. The temperature difference between the tube and the mold prevents the tube from collapsing when the plastic sticks to the mold, and improves the mold release properties. In addition, since plastic tubes maintain a high temperature immediately after coming out of the extruder, they can be easily molded into any shape by simply changing the moving speed of the mold and the type of mold. Effects such as the ability to simplify the manufacturing process by eliminating the need for heating and tension molding can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a process schematic diagram for explaining the present invention in detail, Fig. 2 is a schematic diagram showing a state of clamping by a mold in the present invention, and Figs. 3 and 4 are diagrams showing other methods of the present invention. 5 and 6 are detailed diagrams showing an embodiment of the extruder and tension molding machine of the present invention, and FIG. 7 is a detailed diagram of the water tank and conveyor. In the figure, 1 is an extruder, 2 is a plastic tube, 3 is a tension molding machine, 4.4 is a mold, 6 is a water tank, 8 is a rod, and 9 is a core material.

Claims (1)

[Claims] 1. A method for manufacturing a plastic tube needle, which comprises clamping a high-temperature plastic tube extruded from an extruder with a strongly cooled mold, tension-molding it to a predetermined thickness, and then cooling the molded product.