JPS6025106A - Flame resistant insulated wire - 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 flame-retardant insulated wire, and particularly to a flame-retardant insulated wire that has both high electrical insulation properties and high flame retardancy.

Polyolefin resins generally have excellent electrical insulation properties, but have the drawback of being flammable.

In recent years, there has been a trend that high flame retardancy, such as VW-I of the UL standard, is required for wiring wires for electrical equipment, etc., but for this reason, it is generally necessary to add flame retardants such as halogen-based flame retardants to polyolefin resin. Flame-retardant polyolefin resin compositions containing a large amount of flame retardant have been used as insulators.

However, with this flame retardant method, the electrical insulation properties of the polyolefin resin, especially the voltage resistance properties, are significantly reduced.
1 and high flame retardant 111, etc., there is a problem in applications where it is required to cover both 1 and 111. Therefore, the insulator is made of two layers, and the inner insulator layer is made of polyolefin such as cross-linked polyethylene or polypropylene, which has excellent electrical properties, and the outer sheath layer is made of a highly flame-retardant composition. Two-layer insulated wires with separate functions have been devised.

However, even when a conventional highly flame-retardant composition is used as the outer sheath layer, there is a problem that the inner insulating layer melts and sag, and the combustion continues for a long time, which does not meet the standards. The cause of this is that after the outer sheath layer burns out, no cinders are formed and the internal insulating layer is exposed and covered, or even if cinders are formed, they are not strong enough and cracks occur in the cinders. The internal insulator layer is ignited - Rirta V). Alternatively, the melted internal insulating layer seeped out and ignited, or the cinders were not strong enough to resist the melting pattern [4] of the internal insulating layer, causing sag.

Since high-voltage electric wires for wiring electrical equipment have the following disadvantages, various inventions have been proposed, but none with sufficient characteristics have been found.

The present inventors have conducted various studies based on the viewpoint that the outer sheath layer, which forms a carbonized layer that has higher strength after combustion and is less prone to cracking, can provide more reliable flame retardancy. an inner insulator layer 2 is coated on the inner insulator layer 2;
An insulated wire (first
(see figure), the inner insulating layer is made of a crosslinked or non-crosslinked polyolefin resin composition, and the outer sheath layer is made of (a) a chlorine content of 30 to 45% by weight and a crystallinity of 1.
(b) 5 to 50 parts by weight of zinc borate <C> General formula (where R and R' are a hydrogen element, an alkyl group, a halogenated alkyl group, Carbonyl group, glycidyl group, etc., an organic group having a skeleton of carbon, dihydrocarbon, oxygen, silicon, phosphorus or IA, where X is a bromine element or a chlorine element, It
, m represents a positive integer of O to 4), 1 to 50 parts of bis7Tnol A derivative, (d') mainly consisting of aluminum silicate, magnesium silicate, or a compound of alumina and magnesia. Inorganic filler 5-3
0 parts by weight, (e) 5 to 70 parts by weight of antimony trioxide,
and (``) an insulated wire made of a crosslinked or non-crosslinked chlorinated polyethylene resin composition containing 3 to 50 parts of a lead compound stabilizer has unprecedentedly excellent flame retardancy. I found out.

In the present invention, among (f) lead compound stabilizers, dibasic lead phthalate has the best effect on combustion shell formation even in a small amount4 [No results shown. This has favorable consequences for the mechanical properties of the 11 product.

(d) Inorganic fillers mainly composed of aluminum silicate, magnesium silicate, or a compound of alumina and magnesia include clay, talc, and hydrotalcium.
-, etc. are easy to obtain.

Next, the reason for setting the chlorine content of the chlorinated polyethylene resin (a) to 30 to 45% by weight and the crystallinity to 10% by weight or less is that the chlorine content is less than 30% by weight or the crystallinity is 10% by weight or less. %, the strength of the cinders formed by combustion will not be sufficient, causing a problem with the flame retardancy of the wire. On the other hand, if the chlorine content exceeds 45% by weight, the heat aging resistance of the chlorinated polyethylene used decreases, which is undesirable. In addition, chlorinated polyethylene with a chlorine content within this range includes polyethylene, EPR, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer, as long as the chlorine content in the entire base polymer is 30% or more. Polyolefins such as polyvinyl chloride, vinyl chloride-ethylene copolymers, and other halogen-containing polymers can be blended within 20% by weight.

Furthermore, for each compounding agent, 5 to 50 parts by weight of the above (b) zinc borate, 1 to 50 parts by weight of the above (C) bisphenol A derivative, and 5 to 30 parts by weight of the above (d) inorganic filler. (e) Antimony trioxide in the demo record of the heavy duty department 5
~70 parts by weight, <f) 3 to 5 parts by weight of the above lead compound stabilizer
The reason for this is that if the blending amount is less than these ranges, the strength of the cinders formed by combustion will not be sufficient, causing a problem in the flame retardancy of the electric wire. On the other hand, if it is added in an amount exceeding this range, no improvement in the effect will be seen, and the disadvantage will be that the mechanical strength will be reduced.

In addition, the above-mentioned zinc borate mentioned here is defined in the Encyclopedia of Chemistry V.
Refers to the three compounds described in Oβ, pages 8603-604 (1960) (published by Ritsu Shuppan Co., Ltd.), either singly or as a mixture.

The sheath material used in the present invention may contain compounding agents such as crosslinking agents, crosslinking aids, anti-aging agents, ultraviolet absorbers, plasticizers, fillers, stabilizers, lubricants, colorants, etc. within the usual range. The wire can be crosslinked by means such as radiation crosslinking using ionizing radiation, chemical crosslinking, or silane crosslinking, thereby improving the heat resistance of the electric wire.

=7- Also, as the polyolefin resin used as the insulating layer, polyethylene, polypropylene, polybutene-1
, poly4-methylpentene-1, ■ one or two types of tyrene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-propylene copolymer, or ethylene-propylene-diene terpolymer, etc. A resin composition based on the above blend can be crosslinked by radiation crosslinking using ionizing radiation, chemical crosslinking, silane crosslinking, or the like to improve the heat resistance of electric wires. Additionally, in the case of high-voltage riet wire applications for televisions, it is necessary to pass the high-pressure through test of the UL, SLlb, and 1eCt758 standards, but in this case, it is conducted in a high-temperature atmosphere such as 105°C, so From the viewpoint of mechanical properties, it is preferable to use a resin having a crystal melting point of 105° C. or higher for the insulator. In other words, polyethylene with a density of 0.93 or more is a resin that is relatively easy to crosslink and has a crystalline melting point of 105°C or more, but when used, it has favorable characteristics as a high-voltage lead wire for televisions. You will get what you get later.

Examples of the present invention will be described in detail below in comparison with comparative examples.

Examples 1 to 16, Comparative Examples 1 to 8 On copper wire with a diameter of 0.81 mm 1. : Using a 401 nmφ extruder (1-/D22), polyethylene (Showa Denji Co., Ltd., product name: Seal Urex 34002E) was manufactured at a die temperature of 205°C: Density 0,935, MFRO, 20
) was extrusion coated to a thickness of 0.76 mm, and crosslinked by irradiating it with an IMeV electron beam at 40 M rad. On the other hand, Table-1
The sheet-like composition was mixed with a roll in the composition ratio described in 1. The sheet-like composition was then pelletized to obtain one pellet-like composition. (The temperature resistance of the material when rolled was approximately 140°C.) Next, this pellet was added to 0.95°C of cross-linked polyethylene insulated wire.
It was extruded and coated to a thickness of nv, and then an IMeV electron beam was applied to it.
The completed insulated wire was completed by OM rad irradiation and cross-linking. Each insulated wire thus obtained was subjected to a flame retardant test (UL
, Sub, i 758 VW-1), Ul, 5ub
J, 758 Television Reception Gakugawa High Voltage Wire Standard 3e
(1969) high pressure 1-through test was conducted. Furthermore, since high-voltage electric wires for IV use are generally molded and require high-temperature mechanical strength, the high-temperature mechanical strength was evaluated and the gel fraction was measured by a V-bending test at 160°C. These test results are shown in Table-2.

First, regarding flame retardancy, Example 1.2 using the chlorinated polyethylene of the present invention formed a strong combustion shell without exposing the internal insulating layer after combustion. Therefore, the fire was extinguished immediately after removing the flame from the burner.

On the other hand, Comparative Example 1 using crystalline chlorinated polyethylene.
In case 2, vertical cracks occurred in the combustion shell because the formation of the combustion shell was insufficient. As a result, the internal insulator melted and ignited, causing an afterflame time of over 60 seconds (UL, VW
According to the -1 test standard, the afterflame time must not exceed 60 seconds. ). In Comparative Example 8 using an ethylene-vinyl acetate copolymer grafted with vinyl chloride at about 36% of the chlorine content, a similar combustion phenomenon occurred and the afterflame time exceeded 60 seconds.

Moreover, the good flame retardance of the present invention can be seen in Example 3.4.5.6.
As is clear from 7, bisphenol A-17 (book was transferred from Fire Card 3000 to Fire Card 20
00. Epicote 1001 and NKT Stell 13 P
E-200, and even if the inorganic filler is changed from tallow to clay and hyde (kotal-11ite), there is no change. On the other hand, regarding the amount of compounding agents, Comparative Example 3.4.
5.6.7, the 2j′EA-based phthalN
Even if the amounts of 111, zinc borate, hisphenol A derivative, inorganic filler, and antimony trioxide were reduced, the formation of a combustion shell became insufficient, and the afterflame time exceeded 60 seconds. Furthermore, as is clear from the comparisons between Example 9 and Example 11, Example 12 and Example 8, Example 13 and Example 11, Example 14 and Example 11, and Example 16 and Example 11, Dibasic lead phthalate, zinc borate, phiψ−
Increasing the amount of Guard 3000, Mystron Paper Talc, or Antimony Trioxide does not lead to a significant improvement in afterflame time. Furthermore, as is clear from the comparison between Example 10 and Example 1, when dibasic lead phthalate is replaced with tribasic lead sulfate, the VW-1 test is passed, but the afterflame time is reduced. becomes longer.

In other words, from the above, it can be seen that the chlorinated polyethylene of the present invention and its compounding agents both contain component C, which is essential for the flame retardancy of insulated wires.

Next, regarding the high pressure through characteristics, all the samples whose outer sheath layer was made of a chlorinated polyethylene resin composition passed the high pressure through characteristics.

On the other hand, in the case of Comparative Example 8 using a vinyl chloride grafted ethylene-vinyl acetate copolymer, it did not pass the high pressure through test. The reason for this is that, as shown in the gel fraction results, in Comparative Example 8, the degree of crosslinking was low, and the total coating thickness became thinner due to thermal deformation of the outer sheath layer, resulting in a decrease in withstand voltage characteristics. Ru.

The same can be said about the high temperature V-bending test results.

In both the Examples and Comparative Examples using chlorinated polyethylene, no cracks occurred in the outer sheath layer in the severe high temperature deformation test, but when vinyl chloride grafted ethylene-vinyl acetate copolymer was used, the outer sheath layer did not crack. A crack appeared. The reason for this is thought to be that in the case of the vinyl chloride-grafted ethylene-vinyl acetate tt polymer, the degree of crosslinking is insufficient, which is reflected in the mechanical strength at high temperatures.

As described above, when chlorinated polyethylene is used, it has excellent high pressure throughput characteristics and mechanical strength at high temperatures, and this is due to the high crosslinking efficiency of chlorinated polyethylene. In other words, in the case of an insulated wire with an outer sheath layer made of a chlorinated polyethylene resin composition, it is not only economically advantageous to reduce the amount of irradiation or the amount of crosslinking agent used, but also because it increases the amount of irradiation or crosslinking agent. It also has the advantage of preventing dehydrochloric acid reaction and deterioration of heat aging properties.

That is, the present invention uses chlorinated polyethylene having excellent crosslinking properties to provide excellent flame retardancy.
It can be said that we have developed an insulated wire with excellent high-voltage resistance and molding resistance. The industrial value of this water spray invention is extremely high.

Area Area Area Area - 1 + 1 /// Δ Hemtoya -ki Massage Field's Call ゎ [F] (15) UL, 5 object 758 VW-1 Table -
The longest afterflame time in No. 2 refers to the longest afterflame time for afterflames after 5 sample ignitions, and is averaged over 6 samples.

According to the VW-1 test standard, each afterflame time must not exceed 60 seconds.

(16) LJ L, 5ubject 758 TV
High-voltage wire standard for receivers 3 echionl (196
8th year) High pressure through test. The sample conditions are a voltage resistance test of DC50KV for 7 hours in an atmosphere of 105°C.

(17) After heating the finished product sample at 160°C for 1 hour, bend it into a V shape in the same atmosphere, then bend it back in the opposite direction,
Perform V-shaped bending again and observe the occurrence of cracks in the sheath layer and insulator layer.

(18) Extracted for 8 hours using a Soxhlet extractor filled with tetrahydrofuran.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electric wire according to an embodiment of the present invention. 1... Conductor 2... Internal insulator layer 3...Outer sheath layer. Patent applicant: Furukawa Electric Co., Ltd. Same applicant: Tokyo Special Electric Wire Co., Ltd. Representative Patent Attorney Akatsuki Sugimura Question: Written by Patent Attorney Oki Sugimura =34

Claims (1)

[Claims] 1. An insulated wire comprising an internal insulating layer coated on a conductor and an external sheath layer covering the outer periphery of the internal insulating layer, wherein the internal insulating layer is of a crosslinked or non-crosslinked type. It is composed of a polyolefin resin composition, and the outer sheath layer has (a) a chlorine content of 30 to 45% by weight;
, chlorinated polyethylene resin 10 with a crystallinity of 10% or less
(b) 5 to 50 parts by weight of zinc borate to 0 parts by weight,
(c) General formula (where R and R' are hydrogen elements, carbons such as alkyl groups, halogenated alkyl groups, carbonyl groups, glycidyl groups, etc., nitrogen, oxygen, silicon. 1 to 50 parts by weight of a bisphenol A derivative represented by 1<, X represents a bromine element or a chlorine element, A and m represent positive integers of 0 to 4.
(d) aluminum silicate, magnesium silicate,
Or Teruki filler, which is mainly a compound of alumina and magnesia! 1-30 parts by weight, (e) Andemo trioxide 2
5 to 10 heavy parts, and (f) lead compound stabilizer 3 to 50
1. A flame-retardant insulated wire comprising a cross-linked or non-cross-linked nitrided polyethylene resin composition containing a heavy hot water component. 2. The flame-retardant insulated wire according to claim 1, wherein the lead compound stabilizer (f) is a dibasic former lead phthalate. 3. The flame-retardant insulated wire according to claim 1, wherein the internal insulating layer is made of a crosslinked polyolefin resin composition. 4. The flame-retardant insulated wire according to claim 3, wherein the polyolefin resin constituting the internal insulating layer is polyethylene having a density of 0.93 or more. 5. The flame-retardant insulated wire according to claim 1, wherein the outer sheath layer is made of a cross-linked chlorinated polyethylene resin composition.