JPH04137824U - Crosshead for multilayer extrusion - Google Patents

Abstract

(57) [Summary] [Objective] To provide a crosshead for multilayer extrusion that can stably produce high quality multilayer extrusion coated wire for a long period of time. [Structure] A core nipple 2 through which the core wire 1 passes; a required number of extrusion nipples 4 arranged outside the core wire nipple 2 to form a desired number of internal extrusion layers 3 on the core wire 1;
In a multilayer extrusion crosshead comprising an outer layer die 6 disposed in front of the extrusion nipple 4 and forming an outer extrusion layer 5 on the inner extrusion layer 3, the extrusion nipple 4
The parts where the different extruded layers 3 and 5 are adjacent to each other via the extrusion nipple 4 are constituted by a heat insulating structure, and the mutual thermal influence between the adjacent extruded layers 3 and 5 is alleviated. , 5 from deteriorating or solidifying during extrusion.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention simultaneously extrudes multiple layers of insulation on a core wire, such as the insulated core wire of a communication cable. This invention relates to improvements in crossheads for multilayer extrusion used in

0002

[Conventional technology]

In this type of crosshead, the core wire 1 passes through, as shown in the longitudinal cross-sectional view in FIG. A nipple 2 for the core wire and an internal extrusion layer placed on the outside of the nipple 2 for the core wire and on the core wire 1. An extrusion nipple 4 forming an extrusion nipple 4 and an internal extrusion an outer layer die 6 for forming an outer extrusion layer 5 on the layer 3; The nipple 4 has a nipple 17 directly forming the internal extrusion layer and a nipple holding said nipple. It is composed of a pull holder 8. The multilayer extrusion coated wire produced using such a crosshead is shown in Fig. 3. As illustrated in the cross-sectional view, the core wire 1 is coated with an internal extruded layer 3 and an external extruded layer 5 in sequence. It is of the shape of Furthermore, the above-mentioned crosshead for multilayer extrusion is for the case where the internal extrusion layer is one layer. , when the internal extrusion layer is two or more layers, the crosshead is configured to connect the extrusion nipple to the core. The number of inner extrusion layers formed on the line is equal to the number of layers, and the outer layer is the more extruded. The layer outlet is located in the front and arranged concentrically.

0003

[Problem that the idea aims to solve]

However, the extrusion nipple of the conventional crosshead for multilayer extrusion as described above is , extrusion nipples because they are made of metal materials such as steel and have good thermal conductivity. If the molding temperatures of adjacent extrusion layers are different through the extrusion nipple, As a result, the extruded layer with a high molding temperature is The extruded layer with a low temperature may absorb heat and solidify, or conversely, the extruded layer with a low molding temperature may not be formed properly. There was a problem that the high temperature extrusion layer caused overheating and deterioration of quality.

0004

[Means to solve the problem]

The purpose of this invention is to produce a multi-layer extruded coated wire material that can be stably produced over a long period of time. An object of the present invention is to provide a crosshead for extrusion. That is, the present invention includes a core nipple through which the core wire passes, and a core wire nipple on the outside of the core wire nipple. a required number of extrusion nipples arranged to form a desired number of internal extrusion layers on the core wire; , disposed in front of the extrusion nipple to form an outer extrusion layer on the inner extrusion layer; In a multilayer extrusion crosshead comprising an outer layer die, the extrusion nipple , where different extruded layers are adjacent to each other via the extrusion nipple, are formed into a heat insulating structure. It is characterized by the following.

[0005]The present invention will be specifically explained below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of the multilayer extrusion crosshead of the present invention. A core nipple 2 through which the core wire 1 passes, an extrusion nipple 4 which is arranged outside the core wire nipple 2 and forms the internal extrusion layer 3 on the core wire 1, and an extrusion nipple 4 which is arranged in front of the extrusion nipple 4 and which forms the inner extrusion layer 3. The extrusion nipple 4 is composed of a nipple 7 that directly forms the inner extrusion layer 3, and a nipple holder 8 that holds the nipple. are connected by a removable method such as screwing. Furthermore, since the nipple 7 located between the internal extruded layer 3 and the external extruded layer 5 is formed from a hollow steel material, the internal air layer acts as a heat insulating layer to prevent thermal interference between the extruded layers. eased. In addition to the above-mentioned hollow body, the heat insulating structure of the extrusion nipple used in the crosshead of the present invention may also be a hollow body filled with a heat insulating material such as asbestos or plastic foam. Further, a ceramic having low thermal conductivity such as Al ₂ O ₃ or ZrO ₂ may be used as the constituent material to provide heat insulation properties. In addition, when the extrusion nipple is composed of a nipple and a nipple holder, not only the nipple but also the nipple holder is provided with a heat insulating structure of the shape or material as described above in the portion where different extrusion layers are adjacent to each other via the nipple holder. to alleviate mutual thermal interference. It should be noted that the present invention can provide similar effects even when applied to a crosshead having an extrusion nipple in which the nipple and nipple holder are integrated.

[0006]

[Effect]

In the crosshead for multilayer extrusion of the present invention, the extrusion nipple that forms the internal extrusion layer is , a portion where different extruded layers are adjacent to each other via the nipple is made of a heat insulating structure. Therefore, the molding temperature of each of the adjacent extrusion layers is maintained at an appropriate temperature. Therefore, adjacent extruded layers may solidify or change in quality due to mutual thermal influence. Never.

[0007]

【Example】

The present invention will be explained in detail below using examples. Example 1 A two-layer extruded coated wire was manufactured using a multilayer extrusion crosshead with the structure shown in Figure 1. Ta. Vinyl chloride molded at a temperature of 180℃ as an internal extrusion layer on a core wire with a diameter of 0.4mm. The resin (PVC) was made to a thickness of 0.2 mm, and the molding temperature was 220℃ as an external extrusion layer. Extrusion molding of iron to a thickness of 0.1 mm was carried out to form two layers of extruded coated wire in 16 hours. It was manufactured continuously. Comparative example 1 Is the nipple for the crosshead for multilayer extrusion the same as shown in Figure 2 made of solid steel material? A two-layer extruded coated wire was manufactured by the same method as in Example 1, except that a wire with a structure of Built. A sample was taken out from each of the two-layer extruded coated wires obtained in this way and extruded. The quality of the coating layer was investigated.

[0008] As a result, two-layer extrusion coated wire rod (Example 1) is an extrusion nipple where different extrusion layers are adjacent to each other via the nipple. Since the pull part is hollow, thermal interference between the inner extruded layer and the outer extruded layer is alleviated, and the extruded material is The quality of the covering layer was good over the entire length. In contrast, a two-layer extruded coated wire manufactured using a conventional crosshead (comparative example 1) In the sample after 8 hours from the start of production, thermal decomposition occurred on the surface of the PVC layer. In addition, the sample after 10 hours was molded into a nylon layer. Traces of solidification due to temperature drop were observed everywhere. This is because the nipple used is made of steel. Because it is a solid body made of aluminum, it has good thermal conductivity, and adjacent extruded layers interfere thermally with each other. This is caused by something. The case where the number of extrusion layers is two has been explained above, but the cross section for multilayer extrusion of the present invention The same effect can be obtained even when applied to the production of multilayer extruded coated wire with three or more extruded layers. That's what you get.

[0009]

【effect】

As described above, the crosshead for multilayer extrusion of the present invention is capable of forming extrusion layers. The portions of the output nipple where different extruded layers are adjacent to each other across the nipple have a heat insulating structure. Because it consists of a three-dimensional structure, the temperature of each extrusion layer is maintained at an appropriate temperature, so The resulting multilayer extruded coated wire has high quality as the extruded layer does not deteriorate or solidify. Multilayer extrusion coated wire can be produced stably for a long period of time, and it has a remarkable industrial effect.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a crosshead for multilayer extrusion according to the present invention.

FIG. 2 is a longitudinal sectional view of a conventional crosshead for multilayer extrusion.

FIG. 3 is a cross-sectional view of a two-layer extruded coated wire.

[Explanation of symbols]

1 core wire 2 Nipple for core wire 3 Internal extrusion layer 4 Nipple for extrusion 5 External extrusion layer 6 Outer layer die 7,17 Nipple 8 Nipple holder

Claims (1)

[Scope of utility model registration request] 1. A core nipple through which the core wire passes, a required number of extrusion nipples arranged outside the core wire nipple to form a desired number of internal extrusion layers on the core wire, and a required number of extrusion nipples arranged in front of the extrusion nipple. and an outer layer die arranged on the inner extrusion layer to form an outer extrusion layer on the inner extrusion layer. A crosshead for multilayer extrusion characterized by a flexible structure.