JPS6074A - Method of protecting cable connector - 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 new and simple protective treatment method for the purpose of electrically insulating, waterproofing, moistureproofing, dustproofing, preventing disconnection, etc. of connecting parts of cables, electric wires, etc.

BACKGROUND ART Bonded connections such as cables and electric wires have traditionally been protected by wrapping them with cotton tape or vinyl tape, or by covering them with heat-shrinkable tubes. These methods are effective and simple protection methods when applied indoors in a relatively clean atmosphere or to low-voltage, low-current cables and wires, but if the connections of cables and wires are used outdoors. It is an unreliable protective treatment method that is almost ineffective when buried in water or underground, or used in high temperature and humid conditions, and high voltage and high current are applied. In this case, the reliability becomes lower.

The following methods are used to improve the electrical insulation and environmental resistance of connections such as cables and wires. Namely, (1) a method of wrapping an unvulcanized rubber tape around the connection part, and performing press vulcanization with a mold after the winding to integrate the connection part; (2) a method of wrapping a heat-sealable tape around the connection part, and then winding it; A method of post-heating to form a protective treatment layer on the connection part (3) A method of passing a heat-shrinkable tube containing an adhesive or adhesive through the connection part, shrinking it, and adhering the shrink tube and the connection part to cover it, etc. However, these methods are not necessarily satisfactory in terms of workability, electrical properties, etc. For example, method (1) has excellent properties such as electrical insulation and environmental resistance, but the taping process is time-consuming and requires press vulcanization under pressure. The quality is inferior.

Method (2), like method (1), takes time to tape and also leaves voids between the layers of the wound tape, which can lead to dielectric breakdown in a short period of time and the adhesive strength with the cable or i-line. If there is insufficient water, accidents may occur due to water intrusion. Method (3) is a simple method that simply shrinks the heat shrink tube, but like method (2), it may leave gaps inside the coated material or make it difficult to bond the shrink tube and cables or wires evenly. This can lead to a decline in insulation properties and water intrusion.

As a result of extensive research to overcome the drawbacks of the conventional methods, the present inventors have developed an alpolyhydroxy compound with a melting point in the range of 60 to 100°C, the general formula (I): R (wherein R is a carbon atom). Protection treatment in which a resin layer is formed on the entire inner wall of a heat-shrinkable tube with a thermosetting resin consisting of an incyanate compound and a urethanization catalyst masked by a phenol compound represented by (10 to 60 aliphatic hydrocarbon groups) By placing the cable connection part in the hollow part of the material and then heating the entire protective treatment material to cure the thermosetting resin at the same time as the heat shrink tube shrinks, the connection part of the cable or electric wire can be placed underwater or underground. The present inventors have discovered that even if they are buried or used under dusty conditions, high temperature and high humidity, they do not cause dielectric breakdown and can be easily protected, which is a remarkable effect and has led to the completion of the present invention.

Examples of the polyhydroxy compound having a melting point of about 60 to 100'a used in the present invention include hydrogenated polyhydroxybutadiene polymers (Polytail H1 Polytail HA, Polytail H8, etc. manufactured by Mitsubishi Chemical Corporation), epsilon cabrelactone, etc. ring-opening polymers (Daicel Plaxel 220, Plaxel 212, Plug A/208,
Praxel 205, Praxel 230, Praxel 24
0, etc.], polytetramethylene glycol and polyethylene glycol, which are solid at room temperature. If the melting point of the polyhydroxy compound is less than about 60°C, the melting point when producing a thermosetting resin will be low, causing a problem that it will be difficult to form a resin layer on the inner wall of the heat shrink tube. If it exceeds about 1ooOc, the melting point when producing the thermosetting resin will be high, and therefore the temperature when forming the resin layer on the inner wall of the heat-shrinkable tube will be high, causing the heat-shrinkable tube to shrink or the resin to melt. This causes the problem of hardening.

The molecular weight of the polyhydroxy compound is about 500 to 400.
0 and about 1.5 or more hydroxyl groups are present in the molecule, the thermosetting resin produced has preferable melting point and curing characteristics (does not harden when forming the resin layer, but quickly hardens by heating for hardening) ) occurs.

Examples of the isocyanate compound masked by a phenol compound used in the present invention include diisocyanate compounds such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate, which have the general formula (■); , R represents an aliphatic hydrocarbon group having 10 to 60 carbon atoms), isocyanate compounds masked by toehadecylphenol, undecylphenol, dodecylphenol, tridecylphenol, etc. .

Examples of the urethane (IJt medium) which is a curing accelerator used in the present invention include tin octylate, dibutyltin dilaurate, triethylenediamine, and copper acetate.

The thermosetting resin used in the present invention is prepared from the polyhydroxy compound, an isocyanate compound masked by a phenol compound, and a urethanization catalyst, and other components such as fillers may be added as necessary. The polyhydroxy compound and the incyanate compound are mixed in such a ratio that N0O10H is in the range of about 0.9 to 1.1, and a urethanization catalyst is added to the mixture in a commonly used amount. The prepared thermosetting resin has a melting point of about 30
~100°C, and is a one-component thermosetting resin with extremely excellent characteristics: the curing reaction hardly progresses at temperatures below about 100°C, and curing completes in a short time at temperatures above about 150°C. It also has excellent electrical insulation, water resistance, and adhesive properties after curing.

The heat shrink tube used in the present invention is Teflon IJ resin, Teflon rubber, silicone resin, silicone rubber, FiP
It is a heat-shrinkable tube manufactured from a material such as synthetic resin or synthetic rubber such as T-rubber, butyl rubber, vinyl chloride resin, polypropylene resin, or polyethylene resin.

There are no particular limitations on the method for manufacturing the protective treatment material in which a thermosetting resin layer is formed on the entire inner wall of the heat-shrinkable tube used in the present invention, but after melting the thermosetting resin, Methods such as injection are commonly used. Therefore, the shrinkage temperature of the heat shrink tube needs to be higher than the temperature of the molten resin. Further, it is preferable that the resin layer of the manufactured protective treatment material does not contain air bubbles. If air bubbles are present in the resin layer, the air bubbles tend to remain in the resin layer even after the protective treatment, which is undesirable. The required thickness or volume of the thermosetting resin layer of the protective treatment material manufactured by the above method depends on the shrinkage rate of the heat shrinkable tube.

In other words, a connecting part such as a table is placed in the hollow part of the protective treatment material, the protective treatment material is heated, and the heat-shrinkable tube 7' is shrunk and the thermosetting resin is cured, resulting in heat-shrinked tubes and cables. The thickness or volume of the resin layer may be selected so as to completely fill the space between the resin layer and the joint portion. Therefore, the shape of the hollow part of the protective treatment material in which the joints of cables, electric wires, etc. are disposed and the shape of the heat-shrinkable tube may be any shape as long as it does not interfere with the protection treatment work.

Next, the method of the present invention will be explained based on drawings showing embodiments of the present invention, but the present invention is not limited thereto.

Fig. 1 is a schematic cross-sectional view of one embodiment of the protective treatment material used in the present invention, Fig. 2 is a schematic longitudinal cross-sectional view of the protection treatment material shown in Fig. 1, and Fig. 3 is a schematic cross-sectional view of the protective treatment material shown in Fig. 1. Fig. 1 is a schematic cross-sectional view showing the cable connection section placed on the protective material, and Fig. 4 is a schematic vertical cross-sectional view of the protected area where the cable connection part has been placed on the protective material and cured. .

The protective treatment material shown in Figures 1 and 2 is obtained by inserting a metal rod or glass rod into a heat shrink tube (1
) and the metal rod or glass rod, a thermosetting resin liquid, preferably a vacuum-defoamed thermosetting resin liquid, is injected and then rapidly cooled to form a thermosetting resin layer (2). It is earned by withdrawing your salary. The thickness of the thermosetting resin layer (2) is determined by adjusting the voids. As shown in Figure 6, unvulcanized rubber tape (6) is applied to the part slightly closer to the wire than the connection part (3) where the rubber cable (4) and electric wire (5) are connected, to approximately the same diameter as the rubber cable (4). )
is wound. After the connecting portion (8) is placed on the protective treatment material obtained as described above, first, both ends (1a) and (1b) of the protective treatment material are heat-shrinked, and then the entire protective treatment material is shrunk, Heat and harden the thermosetting resin. When the entire protective treatment material is shrunk, the thermosetting resin layer (2) melts and flows in the directions (1a) and (1b). As the heat-shrinkable dupe contracts, the air inside flows in the direction of resin flow. At this time, a curing reaction of the resin also occurs. When the heat shrink tube is completely shrunk, (1a), (
Part 1b) is overflowing with excess resin, and the air inside is exhausted. When the resin is completely cured, the cross section of the connection section becomes void-free, as shown in FIG.

The cable connection portion obtained as described above exhibits good properties such as not causing dielectric breakdown even when buried in water or underground, or used under dusty, high temperature and high humidity conditions.

Next, the method of the present invention will be explained based on Examples and Comparative Examples.

Example 1 8100 parts (parts by weight, the same applies hereinafter) of polytail, 49 parts of 4,41-diphenylmethane diisocyanate masked with alkylphenol having an aliphatic alkyl A/group having 60 carbon atoms, 6.2 parts of triethylenediamine, and calcium carbonate 100 parts of the mixture was heated and melted, and 800 parts of the mixture was heated and melted.
After vacuum degassing with C, the diameter is 30 mm.

A metal rod with a diameter of 26 mm was inserted into a 0.7 mm thick heat shrink tube manufactured by Nitto Denki Kogyo ■, and injected into the gap between the rod and the heat shrink tube. After quenching, the metal rod was pulled out to produce a protective treatment material.

Chloro on the protective treatment material of length 5o Q mm? With the Ren W rubber cable, place the Ron-covered '1u' and C7 connections, and protect the both ends of the protective treatment material by approximately 20m + nzu: I
was first heat-shrinked at 150°C, and then the entire protected phase was shrunk at the same temperature. After that, heat at 150°C for about 60 minutes.
The resin was completely cured by heating for 7+J. When the resulting connection was cut, the cross section was completely filled with G resin and was in a gay-less state.

200V, 5A by immersing the connected part in water
As a result of carrying out an electric current test, it showed good insulation properties even after one month.

Comparative Example 1 A sample was prepared in which heat-sealing tape was wound instead of the protective treatment material used in Example 1, and a current test was conducted in the same manner as in Example 1. Dielectric breakdown occurred in several hours.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of the protective treatment 4] Kazumi Wlj used in the present invention, Figure 2 is a schematic longitudinal cross-sectional view of the protective treatment material shown in Figure 1, and Figure 3 is a schematic cross-sectional view of the protective treatment material shown in Figure 1. A schematic explanatory cross-sectional view showing the state in which the cable connection part is protected with the protective treatment material shown on the first page, and a longitudinal cross-sectional view schematically showing the part where the cable connection part is protected with the protective treatment material. ) (1): Heat shrink tube (2): Thermosetting resin layer (3): Connection part (4): Rubber cable

Claims (2)

[Claims] (1) A polyhydroxy compound having a melting point in the range of 30 to 100°C, represented by the general formula (I): R (wherein R represents an aliphatic hydrocarbon group having 10 to 6 carbon atoms) The cable connection part is placed in the hollow part of the protective treatment material, which has a resin layer formed on the entire inner wall of the heat shrink tube with a thermosetting resin made of an isocyanate compound masked by a phenolic compound and a urethanization catalyst, and then the cable connection part is placed in the hollow part of the protective treatment material. A method for protecting cable connections, which is characterized by curing the thermosetting resin at the same time as the heat-shrinkable tube shrinks by heating the entire part. (2) The polyhydroxy compound which is a component of the thermosetting resin has a molecule size of 1 soo to 4 ooo, and 1.5
The treatment method according to claim (1), wherein the treatment method has at least three hydroxyl groups.