JP2003251682A - Method for manufacturing long-sized hollow member and long-sized hollow member obtained thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for continuously manufacturing a cylindrical long-sized hollow member having closed both ends or a closed one end and the other end pore when manufacturing the long-sized hollow member by extrusion molding a thermoplastic resin in a cylindrical state and to provide the long-sized hollow member obtained thereby. <P>SOLUTION: Figure shows a sectional view of an overall constitution showing one embodiment of the method for manufacturing the long-sized hollow member. The method for manufacturing the long-sized hollow member comprises the steps of expanding the melt cylindrical thermoplastic resin 2 extruded from a die 3 provided at a distal end of an extrusion molding machine 1 by a compressed are blown from a supply hole 42, pressing the outer peripheral surface of the resin 2 to surfaces of a pair of caterpillar dies 5 provided rearward in a molding direction from the die 3 to form a profile shape. Then, a drawn part 6 is formed of a drawing block 51 installed at a predetermined length interval to the die 5, cooled to be solidified to manufacture the continued long- sized hollow member 7. The drawn part 6 is cut separately by a cutter 8, and the long-sized hollow member 9 with closed both ends is manufactured. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a long hollow body in which a thermoplastic resin melted by an extrusion molding machine is extruded into a tubular shape, and a long hollow body obtained thereby.

[0002]

Blow molding methods and extrusion molding methods are generally known as methods for producing hollow bodies from thermoplastic resins. The blow molding method is a method performed by a hollow molding machine using a hollow metal mold, and is widely used for liquid containers and hose parts. However, the size that can be molded due to the size of the molding machine and the mold is at most 1.5 m or less and the weight is 5 kg or less, and it is impossible to manufacture a long hollow body exceeding 1.5 m. Have difficulty. On the other hand, the extrusion molding method is suitable for continuously producing a long and heavy hollow body such as a circular pipe or a corrugated pipe by using an extrusion molding machine, a die, a caterpillar mold or the like. As a method for producing a long hollow body by giving a shape to the outer shape by using a caterpillar mold by an extrusion molding method, JP-A-2000-104867,
JP-A-11-348146, JP-A-11-10715
There is a bulletin, etc. Further, as a method for producing a long hollow body having a different diameter cross section, there is JP 2001-301010 A.

[0003]

However, the methods described in the above publications are all related to the production of a long hollow body with both ends open, and a long hollow body with both ends closed is not available. Can not. In order to manufacture a long hollow body with both ends closed by the conventional method, it is necessary to cut a tubular extruded product at a certain length and close both ends by post-processing such as parts fusion or adhesion. is there. Since this post-processing step is required, there are many restrictions on strength, shape, wall thickness, etc., and productivity is poor. Therefore, there is a demand for a method of continuously manufacturing a long hollow body having both ends closed.

An object of the present invention is to provide a method for producing an elongated hollow body by extruding a thermoplastic resin into a tubular shape, and to provide a tubular elongated hollow body having both ends closed or one end closed and the other end small hole mouth shape. It is an object of the present invention to provide a continuous production method and a long hollow body obtained by the method.

[0005]

The constitution of the present invention taken to solve the above-mentioned problems is (1) in the method for producing a long hollow body, wherein the thermoplastic resin is formed into a tubular shape by an extruder. In the method for producing a long hollow body by extrusion molding, a drawing forming block is installed in a part of the caterpillar mold at a constant length interval to form a drawing forming part, and a continuous cylindrical shape with both ends closed. (2), which is characterized in that a long hollow body is produced by making a long hollow body and cutting and drawing the drawn portion thereof.
In the drawing forming block of the caterpillar mold of (1), it is characterized in that an elongated hollow body is obtained in which the drawing forming portion is closed at one end and the other end is formed into a small hole mouth shape. The long hollow body obtained thereby is characterized in that at least one produced by the production method described in (1) or (2) is closed.

[0006]

FIG. 1 is a sectional view of the overall construction showing an embodiment of the method for producing a long hollow body of the present invention. A method for manufacturing a long hollow body will be described with reference to FIG. The molten cylindrical thermoplastic resin 2 extruded from the die 3 provided at the tip of the extrusion molding machine 1 is inflated by the compressed air blown from the air supply holes 42, and the outer peripheral surface of the cylindrical thermoplastic resin 2 is also expanded. Is pressed against the surface of a pair of caterpillar molds 5 provided behind the die 3 in the molding direction to form an outer shape.

The compressed air is filled from inside the molten cylindrical thermoplastic resin 2 from the air supply device 4 equipped with the pressure control valve 41 through the air supply hole 42, and expands and changes toward the outer peripheral side. Press on the surface of the caterpillar mold 5.

The caterpillar mold 5 is composed of a plurality of blocks forming a semicircular arc shape and arranged on the left and right sides, and an outer shape forming block 52 forming the outer shape of a hollow body.
And a draw forming block 51 forming the shape of the draw forming section 6. Since the draw forming blocks 51 are installed at constant length intervals, the tubular thermoplastic resin 2 that has passed through the caterpillar mold 5 is cooled and solidified and has a draw forming portion 6 at constant length intervals. It is sent as a continuous elongated hollow body 7. After that, the draw forming section 6 is cut and separated by the cutting device 8 to form the long hollow body 9. In addition, the length of the elongated hollow body 9 can be freely set by the interval of the lengths in which the diaphragm blocks 51 are installed. Further, if the long hollow body 7 is insufficiently cooled and solidified even after passing through the caterpillar mold 5, a cooling device using cold air or cold water may be added behind this.

The cutting device 8 has a structure in which it can move in conjunction with the feed speed of the cylindrical continuous elongated hollow body 7, and the elongated forming body 6 is cut and separated by a cutting blade cutter 81 or the like. Build.

The thermoplastic resin used for the elongated hollow body is reinforced in addition to thermoplastic resins such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polycarbonate (PC). It is also possible to use a material filled with a material or a material for strengthening crosslinking. Generally, the outer diameter of the elongated hollow body is 20 to 100 mm, usually about 50 mm, and
The length is 1.5 to 10 m, usually about 5 m, for example.

FIG. 2 is a sectional view of the shape of a terminal portion showing an embodiment of the elongated hollow body of the present invention. The shape of the terminal portion of the long hollow body can be formed into (a) both ends closed terminal 61, (b) one end closed, the other end small hole mouth-shaped terminal 62 by changing the shape of the drawing forming block 51, and also a circular shape. , Oval, polygonal, and a shape with a concave and convex collar can be freely set.
Similarly, the outer peripheral shape of the elongated hollow body can be freely set by changing the surface shape of the outer shape forming block 52.

[0012]

As described above, according to the method for producing a long hollow body of the present invention, a long hollow body made of a thermoplastic resin having a closed end is continuously processed without post-processing such as fusion bonding and bonding of parts. Since it can be manufactured efficiently, the workability is remarkably improved. Further, by changing the shape of the drawing forming block of the caterpillar mold, not only a long hollow body having both ends closed but also a long hollow body having one end closed and the other end formed into a small hole mouth shape can be formed. In addition, there are few restrictions such as shape and wall thickness, and the terminal shape is circular, oval,
You can freely set polygonal shapes and shapes with uneven flanges. This elongated hollow body can be used as a closed container for liquid substances and powder substances.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the overall configuration showing an embodiment of the method for producing a long hollow body of the present invention.

FIG. 2 is a sectional view of the shape of a terminal portion showing an embodiment of the elongated hollow body of the present invention.

[Explanation of symbols]

1 Extruder 2 Thermoplastic resin 3 dice 4 Air supply device 5 Caterpillar mold 6 Drawing section 7 Continuous long hollow body 8 cutting device 9 Long hollow body 41 Pressure control valve 42 Air vent 51 Block forming block 52 outline forming block 61 Both ends closed terminal 62 Small-hole mouth-shaped terminal 81 cutting blade

Claims (3)

[Claims] 1. A method for producing a long hollow body in which a thermoplastic resin melted by an extruder is extruded into a tubular shape, and a drawing forming block is installed at a certain length interval in a part of a caterpillar mold. The production of a long hollow body, characterized in that a continuous hollow body having a closed tubular shape is formed by forming a draw forming portion and the hollow forming body is cut and separated to obtain a long hollow body. Method. 2. The elongated hollow body according to claim 1, wherein the elongated forming body is a block forming block of the caterpillar mold, wherein one end of the drawing forming portion is closed and the other end is formed into a small hole mouth shape. Body manufacturing method. 3. An elongated hollow body, characterized in that at least one manufactured by the manufacturing method according to claim 1 or 2 is closed.