JPS6250120A - Preparation of thermoplastic shrink tube - Google Patents

Abstract

PURPOSE:To mold an odd-shaped thermoplastic tube, by providing a mold having a specific shape in a thermoplastic tube in molding said tube. CONSTITUTION:A thermoplastic tube 1 is heated and softened by a heating device 2 and a mold 3 having a polygonal cone shape is subsequently pierced through the heated and softened tube 1. The tube 1 is enlarged and expanded from the inside to the diameter direction. At last, the enlarged and molded tube is cooled by a cooling apparatus 4 to obtain an odd-shaped thermoplastic shrink tube.

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND AND OBJECTS OF THE INVENTION The present invention relates to a method of manufacturing thermoplastic shrink tubing.

A conventional method for manufacturing thermoplastic shrink tubes involves applying a pressure difference between the inside and outside of a heated and softened raw material tube to expand and expand the tube in its radial direction. Therefore, only tubes with circular cross sections could be manufactured.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for manufacturing a thermoplastic shrink tube that makes it possible to manufacture a thermoplastic shrink tube of an irregular shape.

[Summary of the Invention In other words, the present invention heats and softens a raw material tube with a heating device disposed around it, and then expands and molds the heated and softened raw material tube using an expansion/expansion means that expands and expands it in the radial direction from the inside. In the method for manufacturing a thermoplastic shrink tube, the expansion/expansion means is held in the heating device and passes through the heated and softened raw material tube, a polygonal conical mold, and the heating device It is characterized by being formed by a cooling device installed at the bottom of the tube and cooling the expanded molded tube, so that a thermoplastic shrinkable tube that conforms to the shape of the molding die can be manufactured. become.

[Example] The present invention will be described below based on the illustrated example. FIG. 1 shows an embodiment of the invention. As shown in the figure, the thermoplastic shrink tube is the raw material tube 1.
is heated and softened by a heating device 2 placed around it,
Next, the heated and softened raw material tube 1 is expanded and molded using an expansion/expansion means to expand and expand it from the inside in the radial direction. In this embodiment, the thermoplastic shrinkable tube is manufactured using such an expanding/expanding means. It was formed by a conical mold 3 and a cooling device 4 provided at the bottom of the heating device 2 and cooling the enlarged tube. By doing so, the expansion/expansion means is held within the heating device 2, and is provided with a polygonal conical molding mold 3 through which the heated and softened raw material tube 1 is penetrated, and at the bottom of the heating device 2. A cooling device 4 that cools the molded tube is used to manufacture thermoplastic shrink tubes that follow the shape of the molding die 3, and irregularly shaped thermoplastic shrink tubes are manufactured. A method for manufacturing a thermoplastic shrink tube can be obtained.

That is, a polygonal conical molding die 3 was used to radially expand the heated and softened raw material tube 1;
As this mold 3, for example, an elliptical mold was used as shown in FIG. This molding die 3 is held in the heating device 2 by hanging it from the upper surface or by fixing it with a magnetic field. After the heated and softened raw material tube 1 is expanded and molded using a molding die 3, it is cooled using a cooling device 4 while maintaining its shape to stabilize the shape. By doing this, the thermoplastic shrinkage duplex can be of any shape depending on the shape of the bottom surface of the molding die 3, and if the molding die 3 is changed, it will not only be the same shape as in the past. Thermoplastic shrink tubes with irregular shapes can be manufactured.

Note that the surface of the molding die 3 may be coated with fluororesin or the like in order to improve slipperiness. Further, it goes without saying that the periphery of the molding die 3 is formed in a spherical shape.

[Effects of the Invention] As described above, the present invention provides a method for manufacturing a thermoplastic shrink tube that makes it possible to manufacture a thermoplastic shrink tube of an irregular shape. can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view showing expansion molding and cooling of a raw material tube in an embodiment of the method for manufacturing a thermoplastic shrink tube of the present invention;
FIG. 2 is a developed view of a polygonal conical molding die according to one embodiment. 1... Raw material tube, 2... Heating device, 3... Molding mold, 4... Cooling device.

Claims (3)

[Claims] (1) A thermoplastic shrinkable tube that heats and softens a raw material tube with a heating device placed around it, and then expands and molds the heated and softened raw material tube with an expansion/expansion means that expands and expands the heated and softened raw material tube in the radial direction from the inside. In the manufacturing method, the expansion/expansion means is provided in a polygonal conical molding mold that is held in the heating device and penetrates the heated and softened raw material tube, and that is provided below the heating device, and A method for manufacturing a thermoplastic shrinkable tube, characterized in that the tube is formed by a cooling device that cools an expanded and molded tube. (2) The method for manufacturing a thermoplastic shrink tube according to claim 1, wherein the surface of the polygonal conical mold is coated with a fluororesin. (3) The method for manufacturing a thermoplastic shrink tube according to claim 1, wherein the polygonal periphery of the polygonal conical molding die is formed on a spherical surface.