JPH11224700A - Closed-end terminal with insulating coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, at a low price, a sealed terminal with insulation coating which can avoid occurrence of a contact accident, etc., to a considerable extent, by improving a temperature characteristic and a mechanical characteristic of a synthetic resin used for the insulation counting by simple means, and by preventing softening of the insulation coating even when a wire joint of a cable has a temperature rise. SOLUTION: This sealed terminal with insulation coating is constituted by inserting a metal crimp sleeve 2 into the cap-shaped insulation 1 made of a synthetic resin. The insulation coating 1 is made of a high-density polyolefin resin formed by cross-linking the polyolefin resin with silane radicals under the condition higher than 100 deg.C and humidity higher 80%, after it is molded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a closed end connector with an insulating cover for crimping and connecting core wires of a cable in electric wiring using a general cable.

[0002]

2. Description of the Related Art Generally, a connection portion of a cable in an electric wiring will be described with reference to FIG. 6 using the same reference numerals for the same portions as in the embodiment. A cap-like insulating material made of a synthetic resin such as nylon or polyethylene is used. A core wire 3b is pulled out from the cables 3 to be connected using a closed end connector with an insulating cover having a structure in which a metal crimp sleeve 2 is inserted inside the coating 11, and the coating of the core wire 3b is removed. Are exposed, and the energizing lines 3a,... Having the same polarity are combined into one and inserted into the crimping sleeve 2 of the closed-end connector with insulating coating. Pressing and deforming the conductors of both cables
And crimped together.

[0003]

In the above-described conventional cable connecting portion processing means, since the insulating coating 11 of the closed end connector with the insulating coating is made of a thermoplastic resin such as nylon or polyethylene as described above, it is thermally deformed. When the connecting portion of the conducting wire is heated due to contact resistance or is easily softened by external heat due to a fire or the like, the conducting wire 3a or the sleeve 2 is exposed. Many of them are stored inside, so the exposed conducting wire 3a
And the sleeve 2 may be in contact with each other, which may easily cause an accident such as a short circuit. To overcome this drawback, polyethylene is densified to improve heat resistance, but this densification requires irradiating electron beams during the manufacturing process or performing chemical treatment with special chemicals. In electron beam irradiation, uniform cross-linking is difficult in the case of complex molded products, and in the chemical treatment method, the moldable temperature range is narrow and the shape of molded products is not only limited. Since special and expensive equipment is required, there is a problem to be solved that requires a lot of expense.

[0004] Therefore, in order to solve the above-mentioned conventional problems, the present invention improves the temperature characteristics and mechanical characteristics of the synthetic resin used for the insulating coating of the closed end connector with the insulating coating by simple means. It is an object of the present invention to provide an insulated closed-end connector capable of considerably avoiding the occurrence of the above-described accidental contact of the current-carrying wire by inexpensively.

[0005]

Means for Solving the Problems A closed-end connector with an insulating cover according to the present invention for achieving the object will be described with reference to symbols used in the description of the appearance and structure of the embodiment. A closed-end connector with an insulating coating in which a metal crimping sleeve 2 is inserted into a cap-shaped insulating coating 1 made of a resin, wherein the insulating coating 1 is formed by molding a polyolefin resin having a silane group. A high-density polyolefin resin obtained by a crosslinking reaction in the presence of a high temperature of 100 ° C. or more and a humidity of 80% or more.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In implementing a closed-end connector with an insulating coating having such a configuration, an insulating coating 1 is prepared by mixing a prescribed amount of a catalyst with an olefin polymer having an active silane group, injection molding and blowing. It is molded into a predetermined shape by a usual molding method such as molding. At this stage, a molded article containing an active silane group in the polymer and capable of being crosslinked with water is obtained. Next, in order to crosslink the polymer containing the active silane group to have a high density, the polymer is chemically reacted with water after molding. The chemical reaction with water may have a humidity of 80% or more, but it is desirable to boil it in boiling water (100 ° C.) for 30 minutes or more in order to increase the reaction rate and increase the degree of crosslinking. Alternatively, it may be accommodated in a steam room. Although the longer the heating time for adding water, the more the crosslinking proceeds,
Since the crosslinking speed slows down in about 3 hours, it is set in consideration of productivity.

The mechanism of the crosslinking is as shown in the structural formula of FIG. 4 when water acts on an aggregate of chain polymers P1, P2,... Having an active silane group consisting of silicon, an alkyl group and oxygen. The active silane group reacts with water to liberate the alcohol, and the silicon in the nearby chain polymer is bonded via the remaining oxygen, and cross-linking occurs between the plurality of chain polymers. In this way, a cross-linking reaction is caused one after another to form a network polymer P3, and the heat resistance and the mechanical properties are improved as compared with the one-dimensional chain polymer aggregate.

[0008] By this crosslinking reaction, when compared with nylon 6 which has been conventionally used in various performances, the heat deformation temperature is higher than 30% and the predetermined shape is maintained even at 300 ° C. It is large and has excellent chemical resistance. In a high temperature range (about 120 ° C.), the tensile strength is about 1 compared to conventional high-density polyethylene.
4 times, the strain rate is about 70% of low density polyethylene,
It is clear that the thermal properties are superior to those of conventional nylon and polyethylene. Further, the insulating coating 1 of the present embodiment has a feature that it does not easily ignite even when heated strongly. This feature is presumably because the high-temperature polyethylene having a network structure was formed by being crosslinked with silicon together with the improvement of the heat resistance and mechanical properties.

The crimp sleeve 2 is the same as that used for the conventional closed-end connector with insulation coating.

[0010]

FIG. 1 is an exploded perspective view showing the structure of a first embodiment.
2 is a cross-sectional view assuming a connection state with the cable of the embodiment, FIG. 3 is a schematic principle diagram of a bridging step, FIG. 4 is a structural formula showing a bridging mechanism, and FIG. 5 is a schematic perspective view of a used state. .

In the first embodiment, the insulating coating 1 shown in FIGS.
% And dry blend. Next, the mixture is put into a molding machine and extruded. In order to cause a cross-linking reaction, as shown in the schematic principle diagram of FIG. 3, it is placed in a (high-temperature) water tank 5 and heated in boiling water 6 at 100 ° C. for 30 minutes or more. In addition, 7
Is a heating burner. The crimping sleeve 2 is made of the same copper as the conventional one.

As shown in FIGS. 2 and 5, the closed-end connector with the insulating coating of the embodiment draws the core wires 3b, 3b from the cable 3, removes the coating to expose the conducting wires 3a, 3a, and 3a, 3a are inserted into the crimping sleeve 2 and pressed from above the insulating coating 1 with a crimping tool (or pliers or the like) to crimp both energizing wires 3a, 3a and the crimping sleeve 2. The connection portion of the connected cable is stored in the connection box 4 as in the conventional example of FIG. still,
It goes without saying that the insulating coating used in this embodiment can be used for insulating coating of crimping parts such as plug-in crimp terminals and chain-type crimp terminals in addition to the closed-end connector (not shown).

Although the embodiments which are considered to be representative of the present invention have been described above, the present invention is not necessarily limited to only the structures of these embodiments. The invention achieves the object of the invention and can be carried out with appropriate modifications within a range having the following effects.

[0014]

The closed-end connector with insulating coating according to the present invention is:
As described above, since the insulating coating uses a polyolefin resin having a silane group that easily reacts with water as a raw material, it is possible to form a high-density polyolefin resin by crosslinking in the presence of moisture after molding. There is no need for special and expensive equipment such as an electron beam irradiation device for increasing the density. In addition, the manufacturing cost can be reduced in combination with the simplification of the process.

The insulating coating made of the high-density polyolefin resin manufactured in this manner has a heat deformation temperature higher than that of conventional nylon or polyethylene by 30% or more and maintains a predetermined shape even at 300 ° C. Even in a high temperature range (about 120 ° C.), the tensile strength, the elastic modulus, and the fatigue strength are all large, and the heat resistance and mechanical properties are remarkably improved. Further, it has a feature that it has excellent chemical resistance and does not easily ignite even when heated strongly. Therefore, even in the case where heat is generated due to contact resistance at a connection point of a current-carrying line of a cable or the like, insulation is not destroyed, and a useful effect of significantly preventing a short circuit accident or the like from being reduced is obtained. It was.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the structure of a first embodiment.

FIG. 2 is a longitudinal cross-sectional view assuming a use state.

FIG. 3 is a schematic principle diagram of a crosslinking step.

FIG. 4 is a structural formula showing a mechanism of crosslinking.

FIG. 5 is a schematic perspective view of a use state.

FIG. 6 is a schematic explanatory view of a conventional general cable connection portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation coating 2 Crimp sleeve 3 Cable 4 Connection box 5 Water tank 6 Boiling water 7 Burner

Claims (1)

[Claims] 1. A cap-shaped insulating coating made of a synthetic resin.
(1) is a closed-end connector with insulating coating in which a metal crimp sleeve (2) is inserted, wherein the insulating coating (1) is
After molding a polyolefin resin having a silane group,
A closed-end connector with an insulating coating made of a high-density polyolefin resin obtained by performing a crosslinking reaction in the presence of a high temperature of 00 ° C. or more and a humidity of 80% or more.