JP3304703B2 - Flame-retardant resin composition and insulated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric wire and the like useful for applications requiring high flame retardancy, such as a high-voltage lead wire of a television receiver and a high-voltage wiring of electronic equipment. The present invention relates to a flame-retardant resin composition having no fine fisheye on its surface, a flame-retardant insulated wire using this composition as a coating material, and its flame-retardant DC high-voltage wire.

[0002]

2. Description of the Related Art A DC high-voltage electric wire used for a high-voltage lead wire of a television receiver is disclosed in Japanese Patent Publication No. 51-84.
No. 65, No. 56-55859, and No. 6
Japanese Patent Application Laid-Open No. 0-38805, Japanese Patent Application Laid-Open No. H5-250928, and the like are known. In order to enhance the flame retardancy of these flame-retardant insulated wires, a composition mainly comprising a terpolymer of ethylene-vinyl acetate-vinyl chloride (Japanese Patent Publication No. 51-8465) or a polyvinyl chloride is mainly used. (Japanese Utility Model Publication No. 56-55859).

[0003]

A polyolefin resin grafted with polyvinyl chloride is disclosed in JP-A-5-25092.
No. 8, as disclosed in Japanese Patent Publication No. 8 (1994), it is a polymer having excellent properties as a high-voltage electric wire for direct current. However, if talc or clay is added to this polymer to increase the flame retardancy, the surface of the extruded electric wire sheath will be damaged. There has been a problem that fine fish eyes are generated and the appearance of the electric wire is impaired.

[0004]

As a result of various studies on the above-mentioned problems, the present inventors have found that a flame-retardant resin composition (A) comprising a polyolefin-based resin component grafted with the above-mentioned polyvinyl chloride to which talc or clay has been added. respect, it found that small fish eyes of the wire surface does not occur by adding a small amount of methyl methacrylate-based resin (B) containing more than a molecular weight of 100,000 of 50% or more, and have completed the present invention .

That is, the present invention provides: (A) a polyolefin grafted with polyvinyl chloride;
50% or less of (B) with a molecular weight of 100,000 or more
Containing methyl methacrylate resin and (C) talc or
Provide a flame-retardant resin composition containing clay. Ma
Polyolefin grafted with polyvinyl chloride
100,000 parts by weight of resin component (A), molecular weight of 100,000 or more
Methyl methacrylate resin containing 50% or more of the above
(B) 0.5 to 8 parts by weight, talc or clay (C) 5 to 8
Also features the flame-retardant resin composition described in which 0 parts by weight are added
Having. Also directly on conductors or on insulated wires
Polyolefin resin grafted with polyvinyl chloride
The outermost layer made of a flame-retardant resin composition mainly composed of
In the case of flame-retardant insulated wires with a
Is also used for the flame-retardant insulated wire that is the flame-retardant resin composition described.
Has features. Also,  Mainly polyethylene on conductor
Provided with an insulating layer made of a resin composition to be
Polyolefin resin grafted with polyvinyl chloride
A sheath layer made of a flame-retardant resin composition mainly composed of
In the flame-retardant DC high-voltage wire having the
Or the flame-retardant resin composition according to the above.
It also has a characteristic for high-voltage wires for direct current.

Hereinafter, the present invention will be described in detail. (1) Flame-retardant resin composition The flame-retardant resin composition of the present invention basically comprises (A) a polyvinyl chloride-grafted polyolefin resin component, (B)
Methyl methacrylate resin having a molecular weight of 100,000 or more;
(C) Contains talc or clay. The flame-retardant resin composition is particularly useful as an insulating layer constituting an insulated wire or a sheath layer constituting a DC high-voltage line.

(I) Polyvinyl chloride grafted polyolefin resin component
(A) The polyvinyl chloride-grafted polyolefin-based resin component (A) constituting the sheath layer contains a polyvinyl chloride-grafted polyolefin as a main component, and a small amount of another polyolefin in a range that does not impair the function of the graft polyolefin. A resin or a vinyl chloride resin may be blended. The backbone polyolefin resin component (A) includes an ethylene-vinyl acetate copolymer grafted with polyvinyl chloride, an ethylene-ethyl acrylate copolymer grafted with polyvinyl chloride, and an ethylene-methyl methacrylate copolymer grafted with polyvinyl chloride. Examples thereof include polymers and chlorinated polyethylene grafted with polyvinyl chloride. The ethylene content in the ethylene-based trunk copolymer is not particularly limited, but is generally 30 to 75% by weight, preferably 40 to 65% by weight. Outside this range, the original properties of the ethylene-based trunk copolymer cannot be exhibited. The amount of vinyl chloride grafted in the graft polymer is not particularly limited as long as flame retardancy is obtained, but is generally preferably about 30 to 80% by weight, and more preferably 50 to 70% by weight. If the graft amount is less than 30% by weight, flame retardancy becomes insufficient, and if it exceeds 80% by weight, flexibility is lost and low-temperature properties are deteriorated.

(Ii) Fish Eye Elimination Component (B) In the flame-retardant resin composition of the present invention, a methyl methacrylate resin containing 50% or more of a fish eye elimination component (B) having a molecular weight of 100,000 or more is used. It is necessary. Incidentally, the methyl methacrylate resin has various molecular weights, for example, a high molecular weight having a molecular weight of 100,000 or more [METABLEN P-501A manufactured by Mitsubishi Rayon Co., Ltd.
(Molecular weight 800,000), Metablen P-531 (Molecular weight 47
For example, a methyl methacrylate resin having a molecular weight of less than 100,000 is known. However, from the viewpoint of disappearance of fish eyes, fish eyes do not disappear with a methyl methacrylate resin having a molecular weight of less than 100,000, so the molecular weight must be 100,000 or more and 50% or more, preferably 80% or more. . As the methyl methacrylate resin, a homopolymer of methyl methacrylate or the methyl methacrylate and a small amount of styrene,
Copolymers with other ethylenically unsaturated monomers such as α-methylstyrene, acrylates and the like can be used. The addition amount of the fisheye disappearing component (B) is based on the base polyvinyl chloride-grafted polyolefin resin component (A) 10
0.5 to 8 parts by weight, preferably 1 to 5 parts by weight per 0 parts by weight
Parts by weight are desirable. If the amount of the fisheye disappearing component (B) is less than 0.5 parts by weight, the fisheye will not be completely eliminated, and if it exceeds 8 parts by weight, the mechanical properties of the sheath will deteriorate and the heat aging resistance will decrease. I do.

(Iii) Flame-retardant component (C) In the flame-retardant resin composition, fisheye is generated by the polyvinyl chloride-grafted polyolefin resin component (A) as the flame-retardant component (C). Only when talc or clay is added, fish eyes do not occur when talc or clay is not added as a flame retardant component. However, if talc or clay is not added, the flame retardancy decreases,
Rejects the combustion test. The amount of talc or clay (C) to be added is 5 to 80 parts by weight, preferably 10 to 60 parts by weight, per 100 parts of resin component (A). Talc or clay
If the amount of (C) is less than 5 parts by weight, the flame retardant effect becomes insufficient, and if it exceeds 80 parts by weight, the mechanical properties deteriorate,
The heat aging resistance also deteriorates.

(Iv) Various additives In the resin composition, organic or inorganic flame retardants, flame retardant aids, coloring agents, antioxidants, stabilizers, crosslinking aids such as polyfunctional monomers, lubricants, etc. Can be added.

(2) Insulated Wire The flame-retardant resin composition may be coated directly on a conductor to form a flame-retardant insulated wire, or may be coated as a sheath material on a normal insulated wire. The insulated wire of the present invention is provided with an insulating layer or a sheath layer made of the above-described flame-retardant resin composition on a conductor by molding means such as extrusion coating, and then irradiated with ionizing radiation such as electron beam irradiation and crosslinked. Alternatively, a chemical cross-linking agent such as an organic peroxide may be previously blended in the insulating layer or the sheath layer for chemical cross-linking.

(3) Flame-retardant DC high-voltage wire The flame-retardant DC high-voltage wire of the present invention is provided with an insulating layer made of a resin composition mainly composed of polyethylene on a conductor, and polyvinyl chloride on the outer periphery thereof. It is a DC high-voltage wire having a structure in which a sheath layer made of a flame-retardant resin composition mainly composed of a polyolefin-based resin grafted with is provided. Of course, the DC high-voltage wire of the present invention can be manufactured in the same manner as in the case of the insulated wire. Examples of the polyethylene constituting the insulating layer of the DC high-voltage line include α-olefin copolymers such as high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-propylene copolymer, and ethylene-1-butene copolymer. Coalescence can be mentioned as a specific example.
In this case, these resins can be used alone or in combination. Various additives such as an antioxidant and a processing stabilizer can be added to the insulating layer as needed.

[0013]

The present invention will be described in more detail with reference to the following Examples, Reference Examples and Comparative Examples , which do not limit the scope of the present invention. <Flame-retardant insulated wire> (Example 1) Ethylene-vinyl acetate copolymer grafted with polyvinyl chloride (EVA content 55%, polyvinyl chloride polymerization degree 14)
100 parts by weight of Sumitomo Chemical Co., Ltd.), 0.5 parts by weight of stearic acid, 25 parts by weight of chlorine-based flame retardant "Dechlorane Plus 25" manufactured by Hooker Chemical Co., and antimony trioxide. A material obtained by adding 15 parts by weight, 25 parts by weight of clay, 10 parts by weight of tribasic lead sulfate, 3 parts by weight of hydrotalcite, and 3 parts by weight of “METABLEN P531” manufactured by Mitsubishi Rayon Co., Ltd. as a PMMA resin was added. The mixture was melt-mixed for 15 minutes with an open roll mixer heated to 0 ° C and pelletized. The above material was melt-extruded onto a 0.8 mmφ tin-plated annealed copper wire so as to have an outer diameter of 2.4φ, and then irradiated with an electron beam having an acceleration voltage of 2 MV at 100 kGy to obtain a flame-retardant insulated wire. The surface of the obtained electric wire was visually inspected for the presence of fish eyes, and the initial tensile strength (conforming to UL standard), elongation (conforming to UL standard), 13
Tensile residual ratio of the sheath that has been heat-aged for 7 days in a constant temperature bath at 6 ° C. [residual ratio (%) = (value after aging / initial value) × 100],
The residual elongation was measured, and the electric wire was subjected to a VW-1 vertical combustion test (based on UL standard). As shown in Table 1, in Example 1 in which 25 parts of clay and 3 parts of PMMA-based resin were added, there was no fish eye on the sheath surface, and a good appearance was obtained.
It also passed the VW-1 combustion test.

(Example 2 , Reference Examples 1-2 and Comparative Examples 1-3) An electric wire was prepared and tested in the same manner as in Example 1 except that talc was replaced with 25 parts by weight of talc instead of 25 parts by weight. The results obtained are shown in Example 2 of Table 1. In addition, a dibasic acid / glycol condensate ("Polysizer-TD" manufactured by Dainippon Ink Industries, Ltd.) is used instead of PMMA resin for the flame-retardant insulated wire material
Shows the 1710 ") results, except for using the prepared test the wire in the same manner as in Example 1, 2 and Reference Examples 1 and 2 of Table 1
You . The conditions and electric wire sizes of the following Reference Examples 1 and 2 and Comparative Examples 1 to 3 that are not described in Table 1 are the same as those of Example 1.
Also in the case of Reference Examples 1 and 2 using a dibasic acid / glycol condensate, there was no fisheye and the specimen passed the VW-1 test. On the other hand, when the PMMA-based resin was not added as shown in Comparative Example 1, fish eyes formed on the sheath surface.
As shown in Reference Example 2 in Table 1, even when talc was used instead of clay, there was no fisheye and the composition passed VW-1. As shown in Comparative Example 2, if no clay or talc is added, fish eyes do not occur, but the flame retardancy deteriorates and the VW-1 test fails. Further, as shown in Comparative Example 3, when the PMMA resin was not added, the fish eyes did not disappear even if the roll mixing time was doubled to 30 minutes.
Rather, the heat aging resistance deteriorates.

[0015]

[Table 1] Note) 1) Mitsubishi Rayon Co., Ltd. “Metaprene-P531,”
Molecular weight = 4.7 million 2) Dainippon Ink Industries, Ltd. “Polysizer-TD1”
710 "

[0016] (Examples 3-6, Reference Example 3 and Comparative Example 4) the amount of the PMMA resin as shown in Example 3-6 5
Parts or 10 parts, and as shown in Reference Example 3, the addition amount of the dibasic acid / glycol condensate was increased to 10 parts.
There is no generation of fish eye also was, but the amount is 10
When the amount is less than 60%, the residual elongation after aging is less than 60%. Therefore, the amount of addition is preferably 8 parts or less. Example
As shown in 5-6 , the addition number of talc was 50 parts or 100 parts.
Even in the case of a large amount such as a part, fish eyes do not occur if a PMMA resin is added. However, when the number of added talc exceeds 80 parts, the residual elongation becomes less than 60%, so that the added amount of talc or clay is preferably 80% or less. When the molecular weight of the PMMA-based resin is smaller than 100,000, fish eyes do not disappear as shown in Comparative Example 4.

[0017]

[Table 2] Note) 1) Mitsubishi Rayon Co., Ltd. “Metaprene-P531,”
Molecular weight = 4.7 million 2) Dainippon Ink Industries, Ltd. “Polysizer-TD1”
710 "3)" Metaprene P-710 "manufactured by Mitsubishi Rayon Co., Ltd.
Molecular weight = 70,000

<Flame-retardant DC high-voltage wire> (Example 7) As a conductor, a seven-stranded conductor (outer diameter 0.7 mm) of an outer diameter 0.26 mmφ tinned soft copper wire (tin plating thickness: about 0.5 μm)
8 mmφ) and high density polyethylene (density = 0.
954, melt flow rate = 0.8; ASTM D1
238) A material obtained by adding 0.3 parts by weight of pentaerythrityltetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] to 100 parts by weight of a material is formed on a conductor by a melt extrusion method. Was extruded to 2.98 mmφ to form an insulating layer.

The resin composition for the sheath was prepared as follows. 0.5 parts by weight of stearic acid, based on 100 parts by weight of an ethylene-vinyl acetate copolymer grafted with polyvinyl chloride (EVA content = 55%, polyvinyl chloride polymerization degree = 1400, manufactured by Sumitomo Chemical Co., Ltd.) Hooker Chemical Co., Ltd.'s chlorine-based flame retardant "Dechlorane Plus 25"
5 parts by weight, 15 parts by weight of antimony trioxide, 2 parts of clay
A material obtained by adding 5 parts by weight, 10 parts by weight of tribasic lead sulfate, 3 parts by weight of hydrotalcite, and 3 parts by weight of “METABLEN P-531” manufactured by Mitsubishi Rayon as PMMA resin was added.
The mixture was melt-mixed with an open roll mixer heated to 40 ° C. for 15 minutes and pelletized. After the above-mentioned material was melt-extruded onto the insulation so as to have an outer diameter of 5.20 φ, 100 kGy of an electron beam having an acceleration voltage of 2 MV was irradiated to obtain a DC high-voltage electric wire. The presence or absence of fish eyes on the surface of the obtained electric wire sheath was visually checked, and the initial tensile strength (according to the UL standard) and elongation (according to the UL standard) of the sheath layer were heat-aged for 7 days in a thermostat at 136 ° C. Tensile residual rate [residual rate (%)
= (Value after aging / initial value) × 100], the residual elongation was measured, and the wire was subjected to a VW-1 vertical combustion test (based on UL standard). As shown in Table 3, 25 parts of clay, P
In Example 7 in which 3 parts of the MMA-based resin was added, there was no fisheye on the sheath surface, the appearance was good, and the VW-1 combustion test was passed.

(Example 8, Reference Examples 4 to 5 and Comparative Examples 5 to 5)
7) Add 3 parts of PMMA resin and 25 parts of clay or
An electric wire was produced in the same manner as in Example 1 using 25 parts of luk.
The test results are shown in Example 7 or 8 in Table 3 and the PMM
3 parts of dibasic acid / glycol condensate instead of A-based resin
Referring to the results except for using 25 parts or talc 25 parts Clay were prepared test the wire in the same manner as in Example 1 of Table 3
Examples 4 and 5 are shown. The conditions and electric wire sizes of the following Examples and Comparative Examples that are not described in Table 3 are the same as those of Example 7.
When using the PMMA resin as shown in Example 7-8, fisheye not, pass the VW-1 test. On the other hand, when the PMMA resin was not added as shown in Comparative Example 5, fish eyes were formed on the sheath surface.
As shown in Example 8 and Reference Example 5 in Table 3, even if talc was used instead of clay, there was no fisheye and V
Pass W-1. As shown in Comparative Example 6, if no clay or talc is added, fish eyes do not occur, but the flame retardancy deteriorates and the VW-1 test fails. Also,
As shown in Comparative Example 7, when the PMMA resin was not added, even if the roll mixing time was doubled to 30 minutes, the fish eyes did not disappear, but rather the heat aging resistance deteriorated.

[0021]

[Table 3] Note) 1) Mitsubishi Rayon Co., Ltd. “Metaprene-P531,”
Molecular weight = 4.7 million 2) Dainippon Ink Industries, Ltd. “Polysizer-TD1”
710 "

(Examples 9 to 12, Reference Example 6 and Comparative Example 8) As shown in Examples 9, 10 and Reference Example 6 , the addition amount of the PMMA resin or the dibasic acid / glycol condensate was 5 parts or 10 parts. When the amount is increased to 10 parts, no fish eye is formed. However, when the added amount is 10 parts, the residual elongation after aging is less than 60%. Therefore, the added amount is preferably 8 parts or less. As shown in Examples 11 and 12 , even when the number of talc added is as large as 50 parts or 100 parts, fish eyes do not occur if the PMMA resin is added. But,
When the number of added talc exceeds 80 parts, the residual elongation rate is 6
Since it is smaller than 0%, the addition amount of talc or clay is preferably 80% or less. When the molecular weight of the PMMA resin is smaller than 100,000, as shown in Comparative Example 8,
Fisheye is not gone.

[0023]

[Table 4] Note) 1) Mitsubishi Rayon Co., Ltd. “Metaprene-P531,”
Molecular weight = 4.7 million 2) Dainippon Ink Industries, Ltd. “Polysizer-TD1”
710 "3)" Metaprene P-710 "manufactured by Mitsubishi Rayon Co., Ltd.
Molecular weight = 70,000

[0024]

According to the present invention, a flame-retardant resin composition which is excellent in flame retardancy and does not cause fish eyes on the surface of an electric wire sheath, a flame-retardant insulated electric wire using this composition as a coating material, and its flame resistance A high-voltage electric wire for flammable direct current is obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 33:12) H01B 7/34 B

Claims (4)

(57) [Claims] 1. A methyl methacrylate resin containing (A) 50% or more of a polyvinyl chloride grafted polyolefin resin component and (B) a resin having a molecular weight of 100,000 or more, and (C)
A flame-retardant resin composition containing talc or clay. 2. A molecular weight of 1 per 100 parts by weight of a polyolefin resin component (A) grafted with polyvinyl chloride.
0.5 to 8 parts by weight of methyl methacrylate resin (B) containing at least 50,000 of at least 100,000, talc or clay (C)
The flame-retardant resin composition according to claim 1, wherein 5 to 80 parts by weight is added. 3. A flame-retardant insulated wire having a structure in which an outermost layer made of a flame-retardant resin composition mainly composed of a polyolefin resin obtained by grafting polyvinyl chloride directly on a conductor or on an insulated wire is provided. A flame-retardant insulated wire, wherein the outermost coating layer is the flame-retardant resin composition according to claim 1 or 2. 4. An insulating layer made of a resin composition mainly composed of polyethylene is provided on a conductor, and a sheath layer made of a flame-retardant resin composition mainly composed of a polyolefin resin grafted with polyvinyl chloride on an outer layer thereof. A flame-retardant direct-current high-voltage wire having a structure provided with: wherein the composition of the sheath layer is the flame-retardant resin composition according to claim 1 or 2.