JPH08295708A - Silicone-grafted polyolefin resin and heat insulated wire having insulator made thereof - Google Patents

Abstract

PURPOSE: To provide a silicone-grafted polyolefin resin which can resist to softening and deformation when exposed to heat of composition and has improved heat resistance properties by subjecting at least one member selected from among a low-density PE, a high-density PE and a low-density linear PE, and a copolymer PP to a silicone grafting reaction. CONSTITUTION: 80-99 pts.wt. at least one polyolefin resin selected from among a low-density PE, a high-density PE and a low-density linear PE is mixed with 20-1 pt.wt. copolymer PP to form 100 pts.wt. mixture. An unsaturated alkoxysilane is grafted onto this mixture in the presence of a radical polymerization initiator to obtain a silicone-grafted polyolefin resin. This resin and a silanol condensation catalyst are kneaded, and the obtained mixture is extruded from an extruder to coat a conductor, and the coated conductor is brought into contact with water in a vulcanization pipe to obtain a crosslinked-resin- coated wire core. A twist of such wire cores is sheathed to obtain a heat- resistant wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat resistant electric wire having good heat resistance when exposed to a fire or the like.

[0002]

2. Description of the Related Art Generally, in a place where a large number of people gather, such as in a theater or a department store, an emergency exit light such as an emergency exit light is provided in order to safely guide people in the venue to an emergency exit in the event of a fire. Is required to remain on for a certain period of time. Therefore, the Fire Service Agency Notification No. 4 also defines the standard, and it is obligatory to use heat-resistant electric wires for small fire circuits such as automatic fire notification of fire fighting equipment and emergency warning equipment. In the present specification, the term "heat resistant electric wire" refers to a general term for electric wires and cables shown in Fire Service Agency Notification No. 10 of 1986. Such a heat-resistant wire is generally formed by coating a conductor with silane-crosslinked polyolefin as an insulator to form an insulating core, and then twisting the plurality of insulating cores together and then forming a metal chemical paper (metal tape and paper). Tape), and a sheath layer of soft vinyl chloride is formed on the metal chemical conversion paper.

[0003]

In such a conventional heat resistant electric wire, since expensive metal chemical conversion paper is formed by taping on the insulating core, the cost is increased. Some electric wire sizes (for example, 0.9 x 2P) satisfy heat resistance characteristics even if this expensive metal chemical paper is not used, but heat resistance characteristics (insulation resistance value) are higher than when metal chemical paper is used. Is low. Heat-resistant wires that do not use metallized paper do not burn when the surrounding area where the heat-resistant wires are laid is burned due to fire or other reasons, because the metallized paper is not taped on the insulation core. There is nothing to block the heat, and the combustion heat of the surroundings will be directly transmitted to the insulator. In addition, when conducting a heat resistance test, a fixed wire (used as ground when measuring insulation resistance) was used to attach a sample heat resistant electric wire to the pearlite plate in an S shape, and a load (depending on the electric wire size) was partially hung. When the heat of combustion is applied in the heat resistance test, the metal chemical paper is not taped on the insulation core.Therefore, the insulation wall thickness is not good at the part fixed by the fixed wire and the load installation part where the load is suspended. The number of fixed wires is reduced, and the fixed wire and the conductor or the wire core are easily contacted.

Therefore, it is necessary to improve safety and reliability in actuality when a fire occurs.

An object of the invention of claim 1 of the present application is to prevent softening and deformation easily even when receiving heat of combustion, and to improve heat resistance.

It is an object of the invention according to claim 2 of the present application to reduce the heat deformation rate of softening and deforming under the influence of combustion heat, and to cause a short circuit or the like due to heat deformation without using expensive metal chemical conversion paper. It is to improve the heat resistance by increasing the insulation resistance.

[0007]

According to the first aspect of the present invention,
A low-density polyethylene, a high-density polyethylene, or a linear low-density polyethylene comprising one or two or more polyolefin resins in an amount of 80 to 99 parts by weight and 20 to 1 parts by weight of a copolymer type polypropylene. is there.

According to a second aspect of the present invention, 80 to 99 parts by weight of a polyolefin resin comprising one kind or two or more kinds of low-density polyethylene, high-density polyethylene, and linear low-density polyethylene and 20 parts by weight of copolymer-type polypropylene are added. It is contained in an amount of 1 to 1 part by weight and is made of a silicone-grafted silane-crosslinked polyolefin.

[0009]

According to the invention of claim 1, 80 to 99 parts by weight of a polyolefin resin comprising one kind or two or more kinds of low-density polyethylene, high-density polyethylene, and linear low-density polyethylene is added with a copolymer-type polypropylene. Since the composition is contained in an amount of 20 to 1 part by weight, it is possible to obtain a silicone-grafted polyolefin resin having improved heat resistance, which is not easily softened or deformed even when it receives combustion heat. Here, the content of polypropylene is set to 1 to 20 parts by weight, because if the content of polypropylene is less than 1 part by weight, the heat deformation rate cannot be lowered and the heat resistance cannot be improved. is there. Further, even if the content of polypropylene is more than 20 parts by weight, there is no change in the reduction of the heat deformation rate and no improvement in the heat resistance.

According to the second aspect of the present invention, a copolymer type polypropylene is added to 80 to 99 parts by weight of a polyolefin resin composed of one or more of low density polyethylene, high density polyethylene and linear low density polyethylene. Since the insulator is composed of silane-crosslinked polyolefin that contains 20 to 1 parts by weight and is grafted with silicone, the heating deformation rate which is softened and deformed by the influence of combustion heat is reduced, and an expensive metal chemical paper is obtained. Even if it is not used, a short circuit or the like due to thermal deformation does not occur, and the insulation resistance can be increased to improve the heat resistance. Here, the content of polypropylene is set to 1 to 20 parts by weight,
This is because if the content of polypropylene is less than 1 part by weight, the heat deformation rate of the insulator of the heat resistant electric wire cannot be reduced and the insulation resistance as the insulator cannot be increased to improve the heat resistance property. . Moreover, even if the content of polypropylene exceeds 20 parts by weight, the heat distortion rate of the insulator of the heat resistant electric wire reaches the lowest value, and the heat distortion rate does not decrease any further. This is because even if the amount is increased, the insulation resistance of the insulator does not rise and the heat resistance characteristics do not change.

[0011]

Embodiments of the present invention will be described below. Low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (L-LDP)
A silicone-grafted polyolefin resin comprising 80 to 99 parts by weight of a polyolefin resin composed of any one or more of E) and 20 to 1 parts by weight of a copolymer type polypropylene in the invention according to claim 1, A heat-resistant electric wire comprising the silicone-grafted polyolefin resin as an insulator is the invention according to claim 2.

LDPE, H as the base resin of the insulator
80 to 99 parts by weight of a polyolefin resin composed of one or more of DPE and L-LDPE, at a low price, with a higher Vicat softening point than these base resins and good compatibility with these base resins. 2 for a copolymer type PP (for example, MI = 2.5, d = 0.90)
The total amount is 100 parts by weight in the range of 0 to 1 part by weight. LDPE and HDP, which are base resins for insulators
Table 1 shows the Vicat softening point and melting point of E and L-LDPE, and the Vicat softening point and melting point of copolymer type PP.

Table 1 As is clear from Table 1, among the insulating base resins, LD
It can be seen that HDPE has a higher Vicat softening point and melting point than PE and L-LDPE. Further, the Vicat softening point and melting point of the copolymer type PP are much higher than the Vicat softening point and melting point of HDPE.

In this way, LDPE, HDPE, L-LD
Copolymer type PP is blended with a polyolefin resin composed of one or more types of PE, and an unsaturated alkoxysilane (for example, vinyltrimethoxysilane) is grafted with a radical polymerization initiator (for example, dicumyl peroxide). React to produce a silicone grafted polyolefin resin. Thus, claim 1
The silicone-grafted polyolefin resin described in 1. can be constituted.

Further, the silicone-grafted polyolefin resin according to claim 1 and a silanol condensation catalyst (for example, dibutyltin dilaurylate) are kneaded, extruded from an extruder and coated on the conductor, and then contacted with water in a vulcanizing tube. And cross-link to obtain an insulated wire core. The heat-resistant electric wire according to claim 2 can be constructed by twisting the thus-obtained insulated cores and coating the sheath.

Comparative examples 1 to 4 are shown in Table 2. In each of the comparative examples, LDPE (MI = 2, d = 0.92, the same applies hereinafter), HDPE (MI = 3, d = 0.95, The same shall apply hereinafter), L-LDPE (MI = 2.5, d = 0.92, the same applies hereinafter), and a polyolefin resin composed of one or more kinds of unsaturated alkoxysilane (for example, vinyltrimethoxysilane). A heat-resistant electric wire is constituted by using a silicone-grafted polyolefin resin produced by a graft reaction of a radical polymerization initiator (for example, dicumyl peroxide) as an insulator.
The heat deformation rate, insulation resistance, and dielectric strength of the insulator of this heat-resistant wire are measured.

Table 2 In Table 2, Comparative Example 1 is 100 parts by weight of LDPE and Comparative Example 2 is
Is 100 parts by weight of HDPE and Comparative Examples 3 and 4 are L-LDP.
To 100 parts by weight of E, 3 parts by weight of unsaturated alkoxysilane (for example, vinyltrimethoxysilane) is added respectively, and a radical polymerization initiator (for example, dicumyl peroxide) is added.
The heat resistance was obtained by using 0.5 part by weight of the silicone-grafted polyolefin resin produced by the graft reaction as an insulator, Comparative Examples 1 to 3 without taping the metal chemical conversion paper, and Comparative Example 4 with taping the metal chemical conversion paper. The heat deformation rate, insulation resistance, and dielectric strength of the electric wire insulator are measured.

In Table 2, the crosslinking accelerator is LDPE (MI =
2, d = 0.92) 100 parts by weight of Irganox 10
5 parts by weight of 10 and 0.5 parts by weight of dibutyltin dilaurate are mixed. Further, in Table 2, the heating deformation rate is 120 ° C. by using an insulating core wire of φ 0.9 mm,
It is done with a load of 1 kg. Further, in Table 2, the size of the electric wire used in the heat resistance test is 0.9 mm × 2P. The heat resistance test is performed by measuring insulation resistance, measuring dielectric strength, and observing flammability. The reference values for the insulation resistance, the dielectric strength, and the flammability are as shown in Table 3.

Table 3 Each value in Table 3 is based on JCMA trial No. 1030 heat resistant wire qualification test standard for small force circuits (the same applies hereinafter).

The flammability shown in Table 3 is obtained by heating the heat-resistant wire passed in contact with the inner wall surface of the heating furnace at both ends for 15 minutes, and immediately after heating the furnace temperature to 380 ° C. according to a predetermined standard. In the test to measure the combustion distance from the inner wall surface of both ends of the heat resistant wire at the time of, the combustion part of the left and right end parts of the heat resistant wire horizontally arranged in contact with the left and right side wall surfaces in the heating furnace,
Both are required to be within 150 mm or less from the inner wall surface of the heating furnace in which the left and right ends of the heat resistant wire are in contact with each other.

Comparing Comparative Examples 1 to 4 in Table 2, among Comparative Examples 1 to 4, Comparative Example 2 using HDPE having a higher Vicat softening point and melting point than LDPE and L-LDPE is another comparative example. It is clear that the heating deformation rate is lower than that of 1, 3, and 4.

Comparative Examples 3 and 4 are both L-LDPE100 having a lower Vicat softening point and melting point than HDPE.
Since 3 parts by weight of unsaturated alkoxysilane is graft-reacted with 0.5 parts by weight of a radical polymerization initiator to the parts by weight of the silicone-grafted polyolefin resin, the insulator is formed. Sex is H
Although inferior to Comparative Example 2 using DPE, Comparative Example 4 in which the metal chemical conversion paper is taped from above the insulating core wire shows that the insulation resistance value is dramatically improved by taping the metal chemical conversion paper. .

Table 4 shows Example A (Examples 1 to 8). In Example A, LDPE, HDPE, L
-A polyolefin resin composed of any one or more of LDPE and having a Vicat softening point of 145 to 153 ° C,
Heating of an insulator of a heat-resistant electric wire formed by blending a copolymer type PP having a melting point of 160 to 170 ° C., and using a silicone grafted polyolefin resin produced by graft reaction of an unsaturated alkoxysilane with a radical polymerization initiator as an insulator. The deformation rate, insulation resistance, and dielectric strength were measured.

Table 4 The cross-linking accelerator in Table 4, the heat deformation rate, the size of the electric wire used in the heat resistance test, and the heat resistance test are the same as those in Table 2.

In Table 4, in Example 1, 99 parts by weight of a polyolefin resin composed of L-LDPE was mixed with 1 part by weight of a copolymer type PP. In Example 2, L-LDP was used.
95 parts by weight of a polyolefin resin made of E was mixed with 5 parts by weight of a copolymer type PP. In Example 3, 90 parts by weight of a polyolefin resin made of L-LDPE was mixed with 10 parts by weight of a copolymer type PP. In Example 4, 80 parts by weight of a polyolefin resin composed of L-LDPE was mixed with 20 parts by weight of a copolymer type PP. In Example 5, 95 parts by weight of a polyolefin resin made of LDPE was mixed with 5 parts by weight of a copolymer type PP, and in Example 6, LDP was used.
90 parts by weight of a polyolefin resin composed of E is mixed with 10 parts by weight of a copolymer type PP. Further, in Example 7, 95 parts by weight of a polyolefin resin made of HDPE was mixed with 5 parts by weight of a copolymer type PP, and in Example 7, 90 parts by weight of a polyolefin resin made of LDPE and 10 parts by weight of a copolymer type PP. It is a mixture of parts.

Looking at Example A (Examples 1 to 8) in Table 4, except that the heat deformation rate of Example 1 is 10%,
The heat deformation rate of Examples 2 to 8 is 4% or less, which is excellent. Furthermore, the insulation resistance values of Examples 2 to 8 are 4.8 MΩ or more and Comparative Example 2 except for 3.6 MΩ of Example 1.
It is twice the insulation resistance value of No. 3.

Comparing Example A (Examples 1 to 8) in Table 4 with Comparative Examples 1 to 4, the heating deformation rates of Examples 2 to 8 are as low as 1 to 4%. Comparative Examples 1, 3, and 4 are significantly inferior to Examples 2 to 8 at 30% or more. Further, the heating deformation rate of Comparative Example 2 is as low as 10%, which is the same value as the heating deformation rate of Example 1, but the insulation resistance of Example 1 is 3.6 MΩ, Example 2 shows 2.4 MΩ, and Example 1 shows superior characteristics. Moreover, Comparative Example 2 is LD
Since HDPE, which is more expensive than PE, is used, Example 1 is superior in terms of cost.

As in the case of the embodiment A, the LD
By including a copolymer type PP having a Vicat softening point of 145 to 153 ° C. and a melting point of 160 to 170 ° C. in a polyolefin resin composed of one or more of PE, HDPE and L-LDPE, the wall thickness can be increased. Insulation resistance (heat resistance) was improved because the decrease occurred on the high temperature side.

Table 5 shows Example B (Examples 9 to 10). Example 9 is the polyolefin resin of Comparative Example 1 and Example 10 is the polyolefin resin of Comparative Example 3.
Each of the copolymer type PP (Vicat softening point is 1
45-153 ° C., melting point 160-170 ° C.),
Table 5 shows the respective results of the heat deformation rate, insulation resistance, and dielectric strength of the insulator of the heat-resistant electric wire formed by extrusion-coating on a conductor and bringing it into contact with water in a vulcanizing tube to crosslink it.

Table 5 The cross-linking accelerator, the heat distortion rate, the size of the electric wire used in the heat resistance test, and the heat resistance test in Table 5 are the same as those in Table 2.

Looking at Example B (Examples 9 to 10) in Table 5, both the heating deformation rate is 2% and the insulation resistance value is 4.8 MΩ.
(Example 9) and 5.0 MΩ (Example 10) show excellent characteristics. Comparing this with Comparative Examples 1 and 3, the thermal deformation rate of Comparative Example 1 is 32%, the insulation resistance value is 0.9 MΩ, the thermal deformation rate of Comparative Example 3 is 30%, and the insulation resistance value is Of 2.4 MΩ, that is, Examples 9 and 10 are several steps superior.

As in the case of Example B, the heat resistance can also be improved by blending the silicone grafted polyolefin with PP.

[0033]

According to the invention described in claim 1, even if it receives combustion heat, it is not easily softened and deformed, and the heat resistance can be improved.

According to the second aspect of the present invention, the heating deformation rate of softening and deforming under the influence of combustion heat is reduced,
Even if an expensive metal chemical conversion paper is not used, a short circuit or the like due to thermal deformation does not occur, and the insulation resistance can be increased to improve the heat resistance.

Claims (2)

[Claims] 1. 80 to 99 parts by weight of a polyolefin resin composed of one or more of low density polyethylene, high density polyethylene and linear low density polyethylene and 20 to 1 parts by weight of a copolymer type polypropylene. A silicone grafted polyolefin resin. 2. A polyolefin resin comprising one or more of low density polyethylene, high density polyethylene, and linear low density polyethylene in an amount of 80 to 99 parts by weight and 20 to 1 parts by weight of a copolymer type polypropylene. A heat-resistant electric wire coated with a silicone-grafted silane-crosslinked polyolefin as an insulator.