JPS5990312A - Method of crosslinking rubber and plastic insulated cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for crosslinking a rubber/plastic insulated cable, and more specifically, the present invention relates to a method for crosslinking a rubber/plastic insulated cable, and more specifically, the invention relates to a method for crosslinking a rubber/plastic insulated cable, and more specifically, a cable coated with a crosslinkable rubber/plastic insulating layer is passed through a crosslinking tube arranged at an angle to form the insulated cable. This invention relates to an improvement in a crosslinking method for crosslinking layers.

To produce a crosslinked rubber/plastic insulated cable, a conductor is coated with a crosslinkable rubber/plastic insulation layer by extrusion, and then passed through a predetermined crosslinking cylinder and heated, thereby forming the insulation layer. It is necessary to crosslink the layers.

On the other hand, the above-mentioned cable crosslinking methods include a method in which the cable to be crosslinked is installed vertically and passed through a crosslinking cylinder, and a method in which the cable is passed through a crosslinking cylinder installed at an angle. However, compared to the former, the latter is generally more widely used because it is easier and cheaper to construct.

By the way, when crosslinking is carried out by passing a cable through a bridging cylinder installed at an angle, if the bridging cylinder becomes long and productivity is increased by increasing the speed at which the cable passes through the bridging cylinder, It is necessary to have a length that is as long as possible. ) The cable has no choice but to advance while sliding on the inner surface of the bridge tube.

However, if this sliding portion is applied before the cable has cooled down, there is a risk of scratches on the cable surface or deformation of the cable.

For this reason, it is known that when the above-mentioned sliding portion is before the cable is cooled, silicone oil is supplied between the cable and the bridge tube at the surrounding portion.

However, since silicone oil has excellent lingering properties on the cable surface, it tends to remain on the cable surface even after the cable passes through the bridge tube, which makes the subsequent cable manufacturing somewhat difficult. is thermally decomposed inside the cross-linked cylinder, and the product becomes a minute glass-like substance that remains on the inner surface of the cross-linked cylinder.The disadvantage is that this glass-like product creates minute scratches on the cable surface. be.

Therefore, the inventors of the present invention have aimed to eliminate the residual lubricant on the cable surface after passing through the cross-linked tube, thereby making it easier to manufacture the cable afterwards, and also to eliminate the formation of glassy substances on the inner surface of the cross-linked tube, thereby improving the cable surface. As a result of our intensive research efforts to provide a method for crosslinking rubber/plastic insulated cables that can completely eliminate the occurrence of scratches, we have developed a synthetic water-soluble polyether-based lubricant to be supplied between the rubber/plastic insulating layer and the crosslinking tube. It has been found that the desired results can be achieved by using oil.

The present invention was completed based on the above findings.

That is, the gist of the present invention is that when crosslinking the insulating layer by passing a goople coated with a crosslinkable rubber/plastic insulating layer through a crosslinking cylinder arranged at an angle, the insulating layer and the crosslinking cylinder are This is carried out while supplying a lubricant made of water-soluble polyether synthetic oil between the insulating layer and the cross-linked tube at the contacting portions.

Next, an embodiment of the present invention will be described with reference to the attached drawings. A polyethylene insulating layer containing a crosslinking agent is extruded and coated on a conductor (not shown) using a predetermined extrusion a (not shown). The produced polyethylene insulated cable 1 was then introduced into a tube 2 with one end directly connected to the crosshead of the extruder and the entire structure slanted, thereby crosslinking the polyethylene insulating layer. do. The heating temperature, heating time, etc. of 1 and J- in the crosslinking cylinder 2 may be appropriately selected from known contents. Thereafter, the cable 1 is introduced into the cooling water 3 filled below the bridge tube 2, where it is cooled to a predetermined temperature, and then pulled out of the bridge tube 2 and transferred to the next manufacturing process.

On the other hand, the bridging tube 2 is provided with a lubricant supply device 5 slightly above the point 4 where the cable 1 contacts the bridging tube 2, and the lubricant supply device 5 sequentially supplies water-soluble lubricant into the bridging tube 2. Ether-based synthetic oil (for example, Nippon Oil & Fats Co., Ltd. product name
Uniloop") 6 is now supplied. Note that 7 is a main body of the supply device including a lubricant supply tank and a lubricant supply pump, 8 is a lubricant supply pipe, and 9 is a valve.

When the cable 1 is crosslinked by passing the crosslinking agent-containing polyethylene insulated cable 1 through the crosslinking tube 2 arranged at an angle, at the point 4 where the cable 1 and the crosslinking tube 2 come into contact, This is carried out while supplying water-soluble polyether synthetic oil 6 between the two.

According to the cross-linking method 5-7 4- of the present embodiment carried out as described above, in the tube portion 4 where the cable 1 and the cross-link tube 2 come into contact, a water-soluble polyether is used as the lubricant supplied between the two. Since the synthetic oil was used, the lubricant adhering to the surface of the cable 1 at the contact point 4 is completely washed away when it passes through the cooling water 3 filled below the bridge tube 2, so that the cable will not be damaged in the future. It is easy to manufacture. Furthermore, unlike silicone oil, polyether-based synthetic oil does not thermally decompose to produce glass-like substances, and therefore the possibility of scratches on the cable surface caused by the glass-like substances is eliminated.

As for the effectiveness of the lubricant itself, there is essentially no difference between silicone oil and water-soluble polyether synthetic oil.

[Brief explanation of the drawing]

The figure is an explanatory diagram of an embodiment of the method for crosslinking a rubber/plastic insulated cable according to the present invention. 1: Cable, 2: Crosslinked pipe, 3: Cooling water, 4: Contact point, 5: Lubricant supply device, o-6- 6: Water-soluble polyether-based synthetic oil (lubricant). -7-

Claims (1)

[Claims] When crosslinking the insulating layer by passing a cable coated with a crosslinkable rubber/plastic insulating layer through a crosslinking tube arranged at an angle, the insulating layer and the crosslinking tube are A method for crosslinking a rubber/plastic insulated cable, characterized in that this is carried out while supplying a lubricant made of water-soluble polyether synthetic oil between the crosslinking tubes.