JPH01156034A - Manufacture of multiple aperture tube - Google Patents

Abstract

PURPOSE:To enable a multiple aperture tube to be manufactured with an excellent dimensional accuracy when the multiple aperture having a plurality of apertures which differ with each other in aperture diameter by varying the gaseous pressure supplied to each of aperture to be formed in accordance with the aperture diameters. CONSTITUTION:At the time when a multiple aperture tube 5 having three apertures 41, 31, 21 of large, middle and small size in its cross-section is molded through an injection molding by a die, the gaseous supplied to each of a plurality of the apertures 41, 31, 21 to be formed from gas conduits 2, 3, 4 of a mandrel 1 via die is varied in accordance with the aperture diameter so as to give gaseous difference to the supplied gas, thereby controlling the diameter of the apertures 21, 31, 41 to be formed with an excellent accuracy.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention manufactures a porous tube with excellent dimensional accuracy in pore diameter by extrusion molding by supplying gas at a pressure corresponding to the pore diameter to each of the pores to be formed. Regarding the method.

Prior Art and Problems Porous tubes having a plurality of holes in their cross section are used in various fields, typified by multi-lumen catheters and endoscope tubes.

Conventionally, a method of manufacturing a porous tube by extrusion molding while supplying gas to each hole formed through a die is a method of supplying gas at the same pressure even when the holes to be formed have different diameters. was known. However, there was a problem in that it was not possible to precisely form the mold to the hole diameter ratio set in the die.

Means for Solving the Problems The present invention overcomes the above problems by varying the pressure of the gas supplied to each hole to be formed depending on the hole diameter.

That is, the present invention uses a die that can independently supply gas to each of the holes to be formed when manufacturing a porous tube having a plurality of holes in its cross section by extrusion molding, and The present invention provides a method for manufacturing a porous tube characterized by controlling the diameter of the holes formed by changing the pressure of gas supplied to each tube.

The diameter of the pores formed can be controlled by creating a pressure difference in the gas supplied to each of the plurality of pores, depending on the pore diameter. Can be molded with high dimensional accuracy.

Furthermore, by changing the pressure or pressure difference of the gas to be supplied, the diameter of the pores formed can be changed.

Exemplification of Components of the Invention In the present invention, a die is used that can independently supply gas to each of the plurality of holes formed.

An example of the structure of the die is shown in FIG. This die has a structure in which three large, medium and small holes can be formed in its cross section, and the mandrel 1 has gas paths 2, 3.4 for independently supplying gas to each of the three holes formed.

With this die, a porous tube 5 having the basic cross-sectional shape shown in FIG. 2 is obtained.

In the present invention, when extrusion molding a porous tube having a plurality of holes in its cross section, the pressure of gas supplied to each of the plurality of holes formed through a die is changed depending on the hole diameter to create a pressure difference in the supplied gas. . Thereby, the diameter of the pores formed can be controlled with high precision.

Although the gas is not limited, air is usually used. The pressure balance of the gas to be independently supplied to each of the holes to be formed is appropriately determined depending on the size of the hole to be formed, the type of molding resin, extrusion molding conditions, etc. From the point of view of hole diameter accuracy, a slight difference in gas pressure is usually sufficient.

By the way, when polyethylene or polyvinyl chloride is molded under normal extrusion molding conditions, the supply gas is o, oot to 0.
By applying a pressure difference in the range of 0.05 kg/c+#, a porous tube having each pore diameter with a dimensional accuracy of ±5017 In or less can be obtained.

In the present invention, by controlling the pressure balance of the supplied gas, it is possible to form a porous tube having multiple holes with different diameters in its cross section with high precision. Can be different perforated tubes. Further, the cross-sectional external shape of the porous tube to be formed can be changed. Furthermore, it is also possible to continuously mold porous duplexes with different pore diameter ratios and cross-sectional shapes by changing the pressure balance of the supplied gas during molding. Therefore, the area occupied by the hole in the cross section can be easily controlled by controlling the hole diameter.

FIG. 2 shows a porous tube 5 obtained as a basic shape by the die shown in FIG.
This is an example of 1.41 molded with high precision.

FIG. 3 is an example of a die formed using the same die so as to have a hole diameter ratio different from that of the basic shape.

This porous tube 6 does not change the pressure of the supply gas to the large hole 42, but further increases the pressure of the supply gas to the small hole 22 and the medium hole 32, that is, the pressure difference of the supply gas in response to the return is made higher than in the case of the basic type. It is made larger and molded.

FIG. 4 is an example of a molded product having a cross-sectional shape different from the basic shape described above using the same die.

This porous tube 7 has a generally triangular cross-sectional outline. This is done by increasing the pressure difference between the supply gases in response to the greeting and balancing the pressures of the supply gases so that the holes 23, 33, and 43 formed have the same diameter.

Figures 5 to 8 show porous tubes 8°9, 10, and 11 having approximately square, oval, or gourd-shaped cross-sectional outlines, respectively.
This is an example. These can also be obtained by using a die that basically forms holes with the same diameter or different diameters, and by balancing the pressure difference of the supplied gas.

In addition, 24, 34, 44, 51°52.5 in each figure
3.54, 55.56, 57, 58, 59°60 are holes in the cross section of the porous tube.

There are no particular limitations on the molding resin used in the present invention (resins used in conventional extrusion molding can be used). There are also no particular limitations on the number of holes to be formed.

Usually, it is a porous tube having 2 to 10 holes in its cross section, but in some cases, such as when molding a porous tube whose cross-sectional outside shape changes sequentially, it is sometimes made to be a porous tube with more than 20 holes.

Effects of the Invention According to the present invention, when extruding a porous tube having a plurality of holes in its cross section, the pressure of gas supplied to each of the holes to be formed is changed according to the hole diameter.
Even when molding a porous tube having a plurality of holes with different diameters, it can be manufactured with high dimensional accuracy.

Furthermore, the same die can be used to produce porous tubes with different pore diameter ratios in cross section and porous tubes with different cross-sectional shapes.

Furthermore, the pressure balance of the supplied gas is changed during extrusion molding, resulting in partially different pore diameter ratios and cross-sectional shapes.

It can also be a perforated tube.

Therefore, it is possible to efficiently produce a porous tube with a large area occupied by the pores, or a well-balanced wall thickness and pore diameter, and a small outer diameter, and also to efficiently carry out profile extrusion molding.

Examples Example 1 A die with a hole diameter ratio of 1.9 between the large hole and the small hole in the mandrel is used, and the hole formed by the large hole is 0.
,012 kg/cJ, and low density polyethylene (MFRl) while supplying air at a pressure of 0,017 kg/cnf to the pores formed by the small holes.
, O) was extruded (150°C) to obtain a porous tube with an outer diameter of 2 mm and having two large and small holes in its cross section.

The pore diameter ratio of two large and small pores in the cross section of the obtained porous tube was 1.8.

Comparative Example 1 The same pressure (0
A porous tube was obtained according to Example 1, except that air was supplied at a rate of 0.007 kg/cJ).

The pore diameter ratio of two large and small pores in the cross section of the obtained porous tube was 2.3.

Example 2 Supply air pressure to the hole formed by the small hole is 0,0
A porous tube was obtained according to Example 1 except that the weight was 30 kg/cr&. The obtained porous tube has a gourd-shaped cross-sectional outline as shown in Figure 8, and the average outer diameter of the pores in the cross-section is 1.0 mm, with a difference of ±
It was 30pm.

In addition, the supply air pressure to the hole formed by the small hole is set to 0.
．． 017kg/cn? Or, when porous tubes were manufactured continuously according to Example 1 while repeatedly changing the supply air pressure to It was possible to obtain a porous tube having repeating shaped porous tube portions.

Example 3 The pore diameter ratio of large holes/medium holes/small holes in the mandrel is 3/2
/1 die, with a pressure of 0,003 kg/cnf for the hole formed by the large hole, and 0,006 kg/cnf for the hole formed by the medium hole.
cnf pressure, 0.008 kIr/clI for the pores formed by the small holes. A porous tube having three large, medium and small holes in its cross section was obtained according to Example 1 while supplying air at a pressure of .

The pore diameter ratio of large pores/medium pores/small pores in the cross section of the obtained porous tube was 6/3/2.

Example 4 Supply air pressure to the hole formed by the medium hole is 0,0
A porous tube having three holes in its cross section was obtained in accordance with Example 3, except that the air pressure was 15 kg/cJ and the air pressure supplied to the holes formed by the small holes was 0.020 kg/cJ.

The obtained porous tube had a generally triangular cross-sectional shape as shown in FIG. 4, and the average outer diameter of the three holes in the cross section was 0.70 mm, with a difference of ±40 μm.

Example 5 A die having a diameter ratio of 1.90 between the large hole and the small hole in the mandrel and having two large holes and two small holes alternately was used, and the hole formed by the large hole was 0. ,0
While supplying air at a pressure of 14 kg/cn (to the holes formed by the small holes at a pressure of 0.019 kg/cJ), two large holes and two small holes were prepared according to Example 1. A porous tube having four holes in its cross section was obtained.

The pore size ratio based on the average pore size of large pores and small pores in the cross section of the obtained porous tube was 1.38. The difference in diameter between the two large holes is 40 μm, and the difference in diameter between the two small holes is 3hm.
Met.

Comparative Example 2 The same pressure (0
A porous tube was obtained according to Example 5, except that air was supplied at a rate of 0.007 kg/cJ).

The pore size ratio based on the average pore size of large pores and small pores in the cross section of the obtained porous tube was 1.75. Also, the difference in diameter between the two large holes is 150 μ■, and the difference in diameter between the two small holes is 18
It was 0 μm.

Example 6 Supply air pressure to the hole formed by the small hole is 0,0
35 kg/cn? A porous tube having 4 holes in its cross section was obtained in the same manner as in Example 5 except that it was closed.

The obtained porous tube had a generally rectangular cross-sectional outline as shown in FIG. 5, and the average outer diameter of the four holes in the cross-section was 0.70 on, and the difference therebetween was ±401JI11.

Example 7 Supply air pressure to the hole formed by the large hole is 0,0
A porous tube having 4 holes in its cross section was obtained in accordance with Example 5 except that the weight was 25 kg/c+J.

The obtained porous tube has an oval cross-sectional outline as shown in FIG. 7, and the average outer diameter of the large holes in the cross-section is 1. omm, and the average outer diameter of the small pores was 0.4+am.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view illustrating a die used in the present invention, Fig. 2 is a cross-sectional view showing a basic porous tube obtained by the above-mentioned die, and Figs. Cross-sectional view 1 illustrating an irregularly shaped porous tube,
FIG. 5, FIG. 6, FIG. 7, and FIG. 8 are cross-sectional views illustrating a porous duplex obtained by the present invention. 1: Mandrel 2.3, 4: Gas path 5.6.7.8.9. lO,11: Porous tube 21.
22, 23, 24° 31.32, 33.34° 41.42.43.44° 51.52.53.54° 55.56.57.58° 59.60: Patent application for holes in cross section of porous tube People Mitsubishi Cable Industries, Ltd.

Claims (1)

[Claims] 1. When manufacturing a porous tube having a plurality of holes in its cross section by extrusion molding, a die capable of independently supplying gas to each of the holes to be formed is used, and a die is used to form the holes. A method for manufacturing a porous tube, characterized in that the diameter of the pores formed is controlled by changing the pressure of gas supplied to each of the pores. 2. The manufacturing method according to claim 1, wherein the die used is manufactured to form holes of different diameters.