JPS6016322B2 - Continuous extrusion vulcanization equipment for rubber or plastic molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides molded articles such as electric wires or rubber or plastic tubes and profiles coated with rubber or plastic such as cross-linked polyolefin, using molten metal salt, low melting point metal, or other liquid heat medium. This is an extrusion continuous vulcanization device that is used to vulcanize under pressure.In order to prevent deformation due to bending of the molded product heated to the vulcanization temperature after vulcanization,
The purpose of this invention is to improve the method so that the pressurized liquid heat medium inside the vulcanization tube does not leak or scatter even when the extrusion vulcanization line is made straight.

For example, when manufacturing comb or crosslinked polyolefin insulated wires using a liquid heat transfer medium such as a molten metal salt, it is necessary to use the liquid heat transfer medium under pressure in order to prevent microvoids (fine bubbles) in the insulation coating. It is preferable. For this purpose, the extruder crosshead is directly connected to the vulcanization tube, the vulcanization tube is filled with a liquid heat medium, the cable is bent upward at the vulcanization tube outlet, and the cable is inserted into the pressurized gas at the vulcanization tube outlet. A method has already been proposed in which the gas is drawn out into the atmosphere through a seal packing. However, in this case, after vulcanization, it is necessary to bend the molded product heated to the vulcanization temperature upward near the outlet of the vulcanization tube, which inevitably causes deformation and damage to the molded product. This problem becomes noticeable when a crosslinked polyolefin is used as a molded article. In order to solve the above problem, it is possible to make the extrusion vulcanization line straight.

However, in that case, the high temperature heat medium inside the vulcanizing tube leaks through the seal at the outlet of the vulcanizing tube and scatters, which is dangerous.
This is not a good idea, as it creates a poor working environment and increases costs due to wasted heat medium. In order to solve the above problems, the present invention maintains the temperature of the liquid heat medium near the outlet of the vulcanization tube lower than the temperature of the liquid heat transfer medium in the entire vulcanization tube, thereby increasing the viscosity and making it difficult to leak. The heating medium itself acts as a liquid packing, and a pressurized space with another seal is placed at the outlet of the vulcanization tube via a seal, and a cooling section with a seal is provided at the outlet to form a multi-stage seal. and has a perfect sealing effect.

Next, it will be explained with reference to the drawings.

In the drawing, a vulcanization tube 2 is directly connected to the extruder crosshead. This vulcanizing tube 2 includes a vulcanizing section 21 that occupies most of its length, and an outlet-side slow cooling section 22 that follows the vulcanizing section 21 . An outlet box 4 is connected to the slow cooling section 22 via an outlet side seal 5, and a packing 6 is provided at the outlet of the outlet box 4.
The cooling unit 41 is directly connected through the cooling unit 41, and the cooling unit 41 is filled with cooling water, and the cooling water is circulated between the cooling unit 41 and the radiator by a pump (not shown).
8 is a seal.

Further, the cooling section 41 can be pressurized, and a shower (not shown) can be arranged inside it. The liquid heat medium 200 used for vulcanization is supplied from a liquid heat medium supply source through the supply pipe 20 while being pressurized by an appropriate pressure supply means (not shown), for example, an accumulator device, and is supplied to the entire inside of the vulcanization pipe 2. Moreover, no gas exists in the vulcanizing tube 2 during normal operation. Further, the liquid heat medium 20 and the supply pipe 201 are pressurized by the pressurizing means connected thereto. A core wire 101 passing through the crosshead 1 is coated with unvulcanized rubber or plastic 102 supplied through an annular gap between the nipple 11 and the die 12.
It takes the form of a cable 10, is extruded from the crosshead, passes through the vulcanization section 21 of the vulcanization tube 2, is heated (or crosslinked) by the liquid heat medium 20 flowing therein, and is heated (or crosslinked) to the seal 5 and packing 6. It passes through the tube and is led out of the tube, then is cooled and wound up.

The liquid heat medium 200 is heated in a pressurized supply means (not shown) to a temperature (for example, 20,000 ℃) above the melting point and is passed through the vulcanization tube from the supply pipe 20 while being pressurized. Inside the vulcanizing tube 2, the vulcanizing material is heated by a heating means (not shown) such as a band heater attached to the outside of the vulcanizing tube 2 so as to maintain an appropriate vulcanization temperature.

In the slow cooling section 22, the liquid heat medium is maintained at a temperature above the melting point and close to the melting point (for example, 150 qo).

In order to lower the temperature of the liquid heat medium in the annealing section 22, for example, a radiator is placed outside the annealing section 22 to circulate low-temperature hot water. Reference numeral 23 denotes a partition wall provided between the vulcanization section 21 and the slow cooling section 22, which functions to prevent heat transfer due to the temperature difference between the heat medium 200 on both sides thereof.

The cape 0' that has passed through the seal 5 passes through the pressurized space in the outlet box 4, then passes through the packing 6 and enters the cooling section 41, where the hot water in the cooling section 41 or the hot water supplied from the shower is absorbed. As a result, the liquid heat medium adhering to the cable surface is washed away.

Thereafter, the cable 10 passes through the packing 8 with hot water adhering to its surface. At this time, the hot water adhering to the cable surface is interposed between the cable 10 and the packing 8 and helps improve sealing performance. The waste liquid in the outlet box 4 is discharged from the hole 3 into the treatment tank. As explained above, according to the present invention, '1} Since the line is straight, there is no need to worry about damage or deformation of the cable due to bending the cable at a high temperature.

'2} Since the slow cooling section 22 is provided, the sealing effect is improved by increasing the viscosity of the liquid heat medium.

'3' seals are provided in multiple stages, and each seal 5,
Since both 6 and 8 are sealed with liquid, the sealing performance is further improved and the sealing effect is perfected.

{4} Since a liquid heat medium is used, pressure and temperature can be set freely, resulting in stable product quality.

{5- Since the inside of the outlet box 4 is pressurized to the pressure of the vulcanizing section 21 or higher, it is possible to prevent the liquid heat medium 200 from flowing out from the seal 5. In carrying out the present invention, the seals 5, 8 and packing 6 are not limited to cone-shaped packings as shown in the drawings, but may be changed to U-packings, lip seals, or other effective sealing methods.

Furthermore, although the above description has been made with reference to the case in which the invention is applied exclusively to cables, it is of course also applicable to molded articles such as rubber or plastic tubes or profiles.

[Brief explanation of drawings]

The drawing is a schematic longitudinal section through the device according to the invention. 1...Cross head, 2...Kaki tube,
4...Exit box, 5...Seal, 6.../
Gunkin, 7...Shower, 10...Kefle, 22...
...Slow cooling section, 200...Liquid heat medium.

Claims (1)

[Claims] 1. A vulcanizing pipe is directly connected to the die exit side of the extruder, an exit box is provided at the exit of the vulcanizing pipe via a seal, and a cooling section is directly connected to the rear of the exit box via a seal. A seal is provided in the vulcanization tube to fill the vulcanization tube with a liquid heat medium under pressure, and a slow cooling section is provided near the exit seal in the vulcanization tube to keep the liquid heat medium in the slow cooling section close to the melting point but above the melting point. Rubber or plastic which is maintained at a high temperature, the space inside the outlet box is kept under pressure, and the cooling section is provided with a water shower or filled with cooling water to make the extrusion vulcanization cooling line straight. Continuous extrusion vulcanization equipment for molded products.