JPS58140213A - Method for plastic covering - Google Patents

Abstract

PURPOSE:To uniformly cover a wire, even though soft one, free from being damaged, by a method wherein whole heater is rotated by making the center axis of a plastic pipe as its center. CONSTITUTION:A plastic pipe 2 is arranged outside a glass fiber 1 and diffused by heating with plural pieces of heater 3, 4 arranged outside, a plastic covered glass fiber 5 is obtained. In this case, the position of plastic pipe is detected with a position detector, a vertically moving board 8 and a horizontally moving board 9 being travelled by a signal processing circuit 7, and the center axis of heater is coincided with the center axis of plastic pipe. And at the same time, a rotary connecting terminal 12 is arranged between the furnace body 10 supporting heaters 3, 4 and a power source 11, and power is supplied to the rotating furnace 10 with a motor for rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for coating the surface of a wire with a thermoplastic.

As a method of coating the surface of the wire with plastic, there is a method of directly coating the plastic with a crosshead while melting the plastic in a heating bath using an extruder. In the conventional equipment in this building, the distance between the wire passing through the crosshead and the parts inside the crosshead, such as the mandrel, is narrow, and soft or easily damaged wires tend to break, making them unsuitable for high-speed applications. There were no drawbacks.

As a way to solve these drawbacks, the patent application
As shown in Japanese Patent No. 019848, there is a method of heating and melting a molded pipe with a heater and testing it.

This method solved the problem of wire breakage, but when the temperature of the heater was raised to increase the coating speed, due to the mismatch between the heater and the formed pipe ll4t+ and irregular dimensions of the heater in the circumferential direction, The tip of the formed pipe is deformed and does not match the axial direction of the wire, making it impossible to cover the pipe.
There were drawbacks such as:

In addition, if the formed pipe has high dimensional accuracy and bending strength,
An effective method is to rotate a molded pipe around its axis to heat it uniformly, but it is difficult to heat suspended solids with high bending strength.
Young's modulus is also about 1001? 'mm2, which increases the 4"i loss of the coated fiber. On the other hand, the Young's modulus is about 1.11 k
In the case of molded pipes such as EVA (ethylene vinyl acedate) rubber (combination of ethylene and alpha olefin) with a low EVA (e.g. The bending occurs due to the rotational moment, making uniform heating difficult.
There was a problem that the coating film thickness became non-uniform.

In order to eliminate these drawbacks, the present invention is characterized in that the entire heater is rotated around the central axis of the plastic pipe to uniformly melt the plastic pipe in the heating bath.
The purpose is to uniformly coat the surface of the soft leg material or easily damaged wire with plastic. The present invention will be explained in detail below with reference to the drawings.

The figure is a schematic diagram of one embodiment of the present invention, in which a molded thermoplastic pipe is applied to cover the surface of glass or fiber.

To carry out this, a plastic pipe 2 is placed outside the glass fiber 1, and is heated and melted by a plurality of heaters 3 and 4 placed outside to obtain a plastic-coated glass fiber 5.

At this time, the position of the plastic pipe is detected by the position detector 6, and the vertical direction (heater direction) moving table 8 and the horizontal direction (parallel direction to the heater) moving table 9 are moved via the signal processing circuit 7, and the heater is moved. Align the center axis with the center axis of the plastic pipe. At the same time, the furnace body 1 supporting the heaters 3 and 4
0 and the power supply 110, a rotary connection terminal] 2 is arranged,
Due to the furnace body 10 rotated by the rotation motor 8;
supply power.

With such a configuration, the central axis of the plastic pipe and the central axis of the heater can be aligned, and the plastic pipe can be uniformly melted in the heating bath.

Next, we will discuss examples. A rubber pipe (outer diameter 20 mm, inner diameter 10 mm'6) made of a copolymer of ethylene and α-olehiine was used, and the inner diameter was 55 fl.
', length 507i7F+ blind resistance furnace (111 force 2 k
w ) as a heating source, an optical fiber (outer diameter 125 μm)
carried out nuclide experiments.

Optical fiber line 1 is s OmA+ to 4 o om
M was coated for up to 7 minutes.

When the coating experiment was performed with the heater rotation stopped, the linear velocity was approximately 200. When the temperature reached, it became impossible to coat the wire and the wire was immediately broken, the pipe surface temperature at that time was unrestricted, and the tip of the pipe was bent.

On the other hand, when a similar coating experiment was conducted with the heater rotating at a rotational speed of 20 rpm, the linear speed was reduced to 4 c) o 7
Even when the wire diameter was increased to n/4), no wire breakage occurred, and the wire diameter shifted only by +5 μm (outside diameter 4. (first difference to l f1 μm)).

Next, another example will be shown. It is harder as a material than EVA and Ethin α-olehiin comonolymer (Young's modulus is approximately 10).
o kgAnm, ) Afroon was used as the coating material 1, and the surface of a glass fiber with an outer diameter of 125 μm was coated 17 while it was moving at a linear speed of 30 m/'A-1, and then the rolling speed was gradually increased to 2
The distance was increased to 50 m and 7 minutes. The outer diameter variation range of the glass fiber coated with this method is 18 μm for an outer diameter of 400 μm.
If this method was not used (when the rotation of the heater was stopped), it would be impossible to cover the wire at a speed of 200 m7, and the wire would break.

Further, the outer diameter variation width at that time was as large as +100 μm.

As explained above, the plastic coating method of the present invention can coat a long wire without damaging the wire, and is suitable for obtaining a coating layer with a uniform outer diameter.

[Brief explanation of the drawing]

The figure is a schematic diagram of an embodiment of the invention. DESCRIPTION OF SYMBOLS 1...Glass fiber, 2...Plastic pipe, 8.4...Heater, 5...Plastic coated glass fiber, 6...Position V release device, 7...Signal processing circuit, 8 ...Vertical movement table, ri...Horizontal movement table, 1
0...Furnace body, 11...Power supply, 12...Rotation connection terminal, 18...Rotation motor. Special liver applicant Japan Amashin Telephone Corporation

Claims (1)

[Claims] 1. In the To method, a wire is passed through a plastic pipe made of molded thermoplastic plastic, and the plastic pipe is heated and melted with a heater to coat the surface of the wire with plastic. A plastic coating method that uses rotation as a lifting device.