JP2002097319A - Flame-retardant polyolefin resin composition and electric wire/cable covered therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin resin composition suitably usable as a covering material for electric wires/cables and improved in flame retardancy without deteriorating its mechanical properties (e.g. breaking strength, tensile strength, elongation), and to provide electric wires/cables covered with the composition. SOLUTION: This flame-retardant polyolefin resin composition comprises (A) 100 pts.wt. of an ethylene-ethyl acrylate copolymer, (B) 50-150 pts.wt. of a metal hydroxide and (C) 0.1-150 pt(s).wt. of silicone powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a flame-retardant polyolefin resin composition, and more particularly, to a mechanical property (for example, a mechanical property (for example,
The present invention relates to a flame-retardant polyolefin resin composition having improved flame retardancy without lowering its breaking strength, tensile strength, elongation, etc., and an electric wire / cable coated with the same.

[0002]

2. Description of the Related Art Conventionally, when a coating material used for a sheath layer, an insulating layer, and the like of an electric wire or cable requires flame retardancy, polyvinyl chloride (hereinafter, referred to as PVC) is used as the coating material. Have been used. However, PVC was suspected of causing harmful gases such as dioxin and hydrogen chloride gas when discarding and incinerating electric wires and cables.
Polyolefin-based resins (for example, low-density polyethylene (LDPE),
Ethylene-vinyl acetate copolymer (EVA), ethylene-
Flame retardancy obtained by mixing a flame retardant composed of a metal hydroxide (eg, magnesium hydroxide, aluminum hydroxide, etc.) with an ethyl acrylate copolymer (EEA), an ethylene-methyl acrylate copolymer (EMA), etc. Polyolefins are being used.

[0003] In recent years, such flame-retardant polyolefins have been desired to be further improved in flame retardancy. As a method of further improving the flame retardancy, for example, compounding a metal hydroxide at a high concentration (for example, 50 to 200 PHR), or using a silicone-based flame retardant auxiliary together with the flame retardant, etc. Can be considered.

[0004]

However, when the metal hydroxide is blended at a high concentration, the mechanical properties (eg, breaking strength, tensile strength, elongation, etc.) of the obtained flame-retardant polyolefin are significantly reduced. there were.

In addition, when a silicone oil-based flame retardant is used as a silicone-based flame retardant, for example, a blooming problem occurs, and when a silicone rubber-based flame retardant is used, the resulting flame retardant is obtained. There is a problem that the mechanical strength of the polyolefin decreases.

For the above reasons, it has been difficult to further improve the flame retardancy without deteriorating the mechanical properties of the flame-retardant polyolefin.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide mechanical properties (for example, breaking strength, tensile strength, etc.) which can be suitably used as a covering material for electric wires and cables. , Elongation, etc.) without providing a flame-retardant polyolefin resin composition having improved flame retardancy.

Another object of the present invention is to provide an electric wire or cable coated with a flame-retardant polyolefin resin composition having excellent mechanical properties and flame retardancy.

[0009]

Means for Solving the Problems The present inventors diligently studied the above-mentioned problems, and as a result, completed the present invention. That is, the present invention is as follows.

The flame-retardant polyolefin resin composition of the present invention contains the following components: (A) 100 parts by weight of an ethylene-ethyl acrylate copolymer; (B) 50 parts by weight to 150 parts by weight of metallic water. Oxides; and (C) 0.1 to 15 parts by weight of silicone powder. Thereby, the above object is achieved.

[0011] In a preferred embodiment, the metal hydroxide is at least one selected from the group consisting of magnesium hydroxide, aluminum hydroxide and calcium hydroxide.
Is a seed.

[0012] In a preferred embodiment, the silicone powder is at least one selected from the group consisting of silicone rubber powder having a functional group and silicone resin powder.

In a preferred embodiment, the average particle size of the silicone powder is from 1 μm to 1000 μm.

Further, the electric wire / cable of the present invention is coated with the above flame-retardant polyolefin resin composition.

As used herein, the term “flame retardant” refers to
It means that it is difficult to burn even if it comes in contact with flame, and it is difficult to continue burning by igniting when ignited. The flame retardancy of electric wires and cables is evaluated according to JIS C 3005. The flame retardancy of a cable inevitably increases as its size increases, and the flame retardancy improves. In addition, if the surface is covered with a nonflammable material such as a metal, the flame retardancy as an electric wire or cable is improved. The flame retardancy described herein is not the structural flame retardancy as described above, but the flame retardancy of the material itself, and is evaluated by an oxygen index measured according to JIS K7201-2. Here, the “oxygen index” is a numerical value expressing the minimum oxygen concentration required for the material to sustain combustion by volume%.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The flame-retardant polyolefin resin composition of the present invention contains the following components: (A) an ethylene-ethyl acrylate copolymer; (B) a metal hydroxide; and (C) a silicone powder.

[0018] The ethylene-ethyl acrylate copolymer used in the flame-retardant polyolefin resin composition of the present invention mainly has basic physical properties (for example, electrical properties such as insulating property and dielectric constant) required for a coating material for electric wires. Properties, mechanical properties such as flexibility, elongation and tensile strength, chemical properties such as chemical resistance, and workability).

Among them, particularly preferred is an ethylene-ethyl acrylate copolymer having an ethyl acrylate content of 5% by weight to 45% by weight in view of mechanical properties and thermal properties.

Alternatively, the ethylene-ethyl acrylate copolymer is used in combination with an acid anhydride-modified polyolefin resin containing, as a copolymerization component, an acid anhydride having at least one vinyl group in the molecule. Is also good. The acid anhydride-modified polyolefin-based resin has an effect of preventing interfacial separation between the metal hydroxide and the ethylene-ethyl acrylate copolymer. Examples of the acid anhydride-modified polyolefin-based resin include an α-olefin / acid anhydride binary copolymer, an α-olefin / acid anhydride / acrylic compound or a vinyl ester compound terpolymer. These may be used alone or in combination.

Examples of the acid anhydride include maleic anhydride,
Itaconic anhydride, citraconic anhydride, glutaconic anhydride and the like are preferred, and maleic anhydride is particularly preferred. The acid anhydride forms a hydrogen bond with the metal hydroxide, and a strong adhesive force is obtained between the metal hydroxide and the ethylene-ethyl acrylate copolymer. Interfacial separation between the hydroxide and the ethylene-ethyl acrylate copolymer is prevented.

As the α-olefin, ethylene,
Propylene, butene-1 and the like are preferred, and ethylene is particularly preferred. The α-olefin is a component that has an affinity for the ethylene-ethyl acrylate copolymer of the acid anhydride-modified polyolefin-based resin, and from this viewpoint, the α-olefin is an ethylene-ethyl acrylate copolymer. It is particularly preferred to use ethylene so that good affinity is obtained.

The acrylic compound is preferably acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, etc., and particularly preferably ethyl acrylate. As the vinyl ester compound, vinyl acetate and the like are preferable.

The content of the acid anhydride in the acid anhydride-modified polyolefin resin is, for example, usually 0.05% by weight to 10% in the case of an α-olefin / acid anhydride binary copolymer.
% By weight, preferably 0.1% by weight to 5.0% by weight, and in the case of α-olefin / acid anhydride / acrylic compound or vinyl ester compound terpolymer, usually 0.05% by weight. % To 10% by weight, preferably 0.1%
% To 5.0% by weight. When the content of the acid anhydride is out of the above range, the obtained resin composition tends to have low tensile strength.

The weight ratio of the ethylene-ethyl acrylate copolymer to the acid anhydride-modified polyolefin resin is preferably from 99: 1 to 50:50, more preferably from 97: 3 to 65:35. When the compounding weight ratio is out of the above range, the mechanical properties of the obtained resin composition (for example,
Rupture strength, tensile strength, elongation, etc.).

The metal hydroxide used in the flame-retardant polyolefin resin composition of the present invention acts as a flame retardant. Examples of metal hydroxides include magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like, and these metal hydroxides may be used alone,
Further, they may be used in combination.

The amount of the metal hydroxide in the flame-retardant polyolefin resin composition of the present invention is 50 to 150 parts by weight based on 100 parts by weight of the ethylene-ethyl acrylate copolymer. Preferably 70 parts by weight to 1
It is 30 parts by weight, more preferably 80 to 100 parts by weight. When the amount is more than 150 parts by weight, the mechanical properties (eg, breaking strength, tensile strength, elongation, etc.) of the obtained resin composition are reduced. When the amount is less than 50 parts by weight, the flame retardancy of the obtained resin composition is reduced. Is reduced.

The metal hydroxide is preferably in the form of a powder, and has an average particle size of preferably 0.1 μm to 20 μm.
m, more preferably 0.5 μm to 5 μm. When the average particle size is smaller than the above range, sufficient flame retardancy cannot be obtained, and when the average particle size is larger than the above range, mechanical properties (eg, breaking strength, tensile strength, elongation, etc.) of the obtained resin composition deteriorate. There is a problem of doing.

The average particle size of the metal hydroxide in the present specification is a value measured by a laser diffraction scattering method.

The metal hydroxide may be subjected to a surface treatment with a coupling agent for the purpose of improving the adhesiveness to the ethylene-ethyl acrylate copolymer in the resin composition. As the coupling agent, an aminosilane-based coupling agent, an aminotitanate-based coupling agent, and the like are preferable. Furthermore, in order to improve the elongation and abrasion resistance of the resin composition, a fatty acid (preferably having 15 to 20 carbon atoms) is used instead of a part of the metal hydroxide surface-treated with a coupling agent. May be blended with a metal hydroxide surface-treated. Specific examples of fatty acids include, for example, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and the like.

As the aminosilane coupling agent,
γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, aminobenzenetriethoxysilane, N- 4,4'-methylenebisbenzeneamino-cyclohexanolethyltrimethoxysilane, N-4,4'-methylenebisbenzeneamino-2-
Hydroxypropyloxypropyltrimethoxysilane, N-aminobenzenemethylene-p-phenylene-γ
-Ureidopropyltrimethoxysilane, N-4,4 '
-Oxybisbenzeneamino-cyclohexanolethyltrimethoxysilane, N-4,4'-oxybisbenzeneamino-2-hydroxypropyloxypropyltrimethoxysilane, N-aminobenzeneoxy-p-phenylene-γ-ureidopropyltrimethoxysilane Methoxysilane,
N-4,4'-sulfonylbenzeneamino-cyclohexanolethyltrimethoxysilane, N-4,4'-sulfonylbenzeneamino-2-hydroxypropyloxypropyltrimethoxysilane, N-aminobenzenesulfonyl-p-phenylene-γ -Ureidopropyltrimethoxysilane, Np-phenylenediamino-cyclohexanolethyltrimethoxysilane, Np-phenylenediamino-2-hydroxypropyloxypropyltrimethoxysilane, Np-phenylenediamino-
γ-ureidopropyltrimethoxysilane and the like, and one or more of these are used.

As aminotitanate coupling agents, γ-aminopropyltriethoxytitanium, N
-Β- (aminoethyl) -γ-aminopropyltrimethoxytitanium, γ-ureidopropyltriethoxytitanium, γ-anilinopropyltrimethoxytitanium, aminobenzenetriethoxytitanium, N-4,4′-methylenebisbenzeneamino -Cyclohexanolethyltrimethoxytitanium, N-4,4'-methylenebisbenzeneamino-2-hydroxypropyloxypropyltrimethoxytitanium, N-aminobenzenemethylene-p-phenylene-γ-ureidopropyltrimethoxytitanium, N-
4,4′-oxybisbenzeneamino-cyclohexanolethyltrimethoxytitanium, N-4,4′-oxybisbenzeneamino-2-hydroxypropyloxypropyltrimethoxytitanium, N-aminobenzeneoxy-p-phenylene-γ -Ureidopropyltrimethoxytitanium, N-4,4'-sulfonylbenzeneamino-cyclohexanolethyltrimethoxytitanium, N-4,
4′-sulfonylbenzeneamino-2-hydroxypropyloxypropyltrimethoxytitanium, N-aminobenzenesulfonyl-p-phenylene-γ-ureidopropyltrimethoxytitanium, Np-phenylenediamino-cyclohexanolethyltrimethoxytitanium, N −
Examples include p-phenylenediamino-2-hydroxypropyloxypropyltrimethoxytitanium, Np-phenylenediamino-γ-ureidopropyltrimethoxytitanium, and one or more of these are used.

The method for surface treatment of the metal hydroxide with a coupling agent or a fatty acid is not particularly limited, and a general method, for example, a method in which the metal hydroxide is charged into an alcohol solution of the coupling agent or the fatty acid. A so-called slurry method of drying after treatment or a dry method of directly spraying a coupling agent or a fatty acid onto the metal hydroxide powder is used. The amount of the coupling agent or the fatty acid used varies depending on the type of the coupling agent or the fatty acid, but is usually 0.1 per 100 parts by weight of the metal hydroxide.
002 parts by weight to 5.0 parts by weight, preferably 0.1 part by weight.
Parts by weight to 3.0 parts by weight.

The silicone powder used in the flame-retardant polyolefin resin composition of the present invention acts as a flame-retardant aid. Examples of the silicone powder include silicone rubber powder and silicone resin powder having a functional group. Examples of the functional group include a hydroxyl group, a carbonyl group, an amino group, a vinyl group, an epoxy group, a methacryl group, an acryl group, an alkyl group optionally having one or more substituents, and one or more substituents. And an aromatic hydrocarbon group which may be mentioned, and each substituent is a hydroxyl group, a carbonyl group, an amino group, a vinyl group,
It is selected from the group consisting of an epoxy group, a methacryl group and an acrylic group. Particularly, those having a methacryl group are preferable from the viewpoint of flame retardancy. Specific examples of silicone powders include DC4-7081, SJ053 (all trade names; manufactured by Dow Corning Toray Silicone Co., Ltd.). These silicone powders may be used alone or in combination.

The amount of the silicone powder in the flame-retardant polyolefin resin composition of the present invention is based on 100 parts by weight of the ethylene-ethyl acrylate copolymer.
0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight. When the amount is more than 15 parts by weight, the mechanical properties (eg, breaking strength, tensile strength,
Elongation) decreases and becomes less than 0.1 part by weight,
There is a problem that the flame retardancy of the obtained resin composition is reduced.

The average particle size of the silicone powder is preferably 1 μm to 1000 μm. When the average particle size is smaller than the above range, sufficient flame retardancy cannot be obtained, and when the average particle size is larger than the above range, mechanical properties (eg, breaking strength, tensile strength, elongation, etc.) of the obtained resin composition deteriorate. There is a problem of doing.

The average particle size of the silicone powder in the present specification is a value measured by a laser diffraction scattering method.

By incorporating the above-mentioned silicone powder as a flame retardant aid into a flame-retardant polyolefin resin composition, the amount of the metal hydroxide as a flame retardant is not increased (that is, the mechanical properties are improved). (Without lowering) flame retardancy can be improved.

The flame-retardant polyolefin resin composition of the present invention contains a halogen-free rubber for the purpose of further reducing the impact force applied to the adhesive interface between the metal hydroxide and the ethylene-ethyl acrylate copolymer. May be appropriately compounded. The rubber containing no halogen means a rubber containing no halogen having a tensile modulus of 50 MPa or less. For example, polyisobutylene, butyl rubber, ethylene-propylene rubber (EPM, EPDM), silicone rubber, and vinyl acetate are used in an amount of 40% by weight. % To 60% by weight of an ethylene-vinyl acetate copolymer (EVA), a dynamically crosslinked product of an ethylene-propylene copolymer and polypropylene (for example, Santoprene (trade name, manufactured by AES Japan, trade name)), and a density of 0.91 g / cm ³ or less of 1-butene homopolymer (for example, Tuffmer A (trade name, manufactured by Mitsui Chemicals, Inc.)).

The tensile modulus of the ethylene-ethyl acrylate copolymer and the acid anhydride-modified polyolefin resin is greater than 50 MPa, and is not rich in rubber-like elasticity such as the rubber containing no halogen. For example, the same ethylene-propylene copolymer having a tensile modulus of 50 MPa or less is used as a halogen-free rubber, and one having a tensile modulus of more than 50 MPa is used as a polyolefin resin.

Incidentally, the tensile modulus of elasticity here is based on JIS K
This is a value measured by the measurement method 7113.

In the embodiment in which the rubber containing no halogen is mixed, the compounding ratio of the ethylene-ethyl acrylate copolymer to the rubber containing no halogen in the flame-retardant polyolefin resin composition is 99.5: 0.5. ~ 90: 1
0 (weight ratio), preferably 99: 1 to 95: 5.
If the amount of the rubber is more than the above ratio, the mechanical strength such as the tensile strength and the heat resistance of the obtained resin composition tend to decrease, and if the amount is too small, the effect of the rubber is hardly obtained.

The flame-retardant polyolefin resin composition of the present invention may further contain a halogen-free additive, if necessary. Such additives include, for example, antioxidants, processing aids, stabilizers, fillers, colorants, carbon black, crosslinking agents, lubricants, antistatic agents, and the like.

The flame-retardant polyolefin resin composition of the present invention is prepared by kneading an ethylene-ethyl acrylate copolymer, a metal hydroxide and a silicone powder by a known kneading method such as a Banbury mixer, a pressure kneader or a twin-screw extruder. It is prepared by kneading with an apparatus. The obtained resin composition can then be formed into a coating material of a desired form by injection molding, rotational molding, press molding or the like.

The flame-retardant polyolefin resin composition of the present invention has improved flame retardancy without lowering mechanical properties (eg, breaking strength, tensile strength, elongation, etc.).
It can be suitably used as a covering material for a cable.

The electric wire / cable of the present invention is coated with the above flame-retardant polyolefin resin composition. The coating method is not particularly limited, and includes, for example, extrusion molding. The electric wire / cable coated with the flame-retardant polyolefin resin composition of the present invention has excellent mechanical properties and flame retardancy.

[0047]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

(Examples 1 to 5, Comparative Examples 1 to 3) Each component shown in Table 1 was put into a Banbury mixer (manufactured by Toyo Seiki Seisakusho) at once and kneaded for 20 minutes.
It molded at 60 degreeC for 10 minutes, and produced the test sheet of each Example and each comparative example. In addition, the resin composition obtained by the above kneading was placed on a 2 mm ² conductor as an insulating layer by 0.8 m.
m and a test wire of each example and each comparative example was produced. The following evaluation tests were performed on each test sheet and test wire. Table 2 shows the obtained evaluation results.
Shown in

In Table 1, the amounts of each component are parts by weight, EEA is an ethylene-ethyl acrylate copolymer, EA is ethyl acrylate, and the acid anhydride-modified polyolefin resin is ethylene / anhydrous. It is a maleic acid / ethyl acrylate copolymer (maleic anhydride content: 3% by weight, ethyl acrylate content: 2% by weight), and silicone rubber powder is DC4-7081 (trade name; functional group: methacryl group; Toray Co., Ltd.) Dow Corning
Silicone Co., Ltd.), the antioxidant is a hindered phenol-based antioxidant, and the processing aid is calcium stearate. In addition, low density polyethylene, EEA
The MFR (melt flow rate) of the acid anhydride-modified polyolefin resin is a value measured according to JIS K 6992.

[Evaluation Test] (Tensile Properties) Tensile strength (MPa) and elongation (%) of a test sheet having a thickness of 1 mm were measured in accordance with JIS K7113.

(Flame Retardancy) The oxygen index (LOI) of a test sheet having a thickness of 1 mm was measured in accordance with JIS K 7201-2 to evaluate the flame retardancy. The higher the oxygen index obtained, the better the flame retardancy. In addition, the test wires were subjected to a 60 ° tilt flame retardant test according to JIS C 3005, and the fire was extinguished within 60 seconds after the test wires of Examples 1 to 5 and Comparative Examples 1 to 3 were ignited. (Self-extinguishing) was considered as acceptable.

[0052]

[Table 1]

[0053]

[Table 2]

As can be seen from Table 2, the test sheets of the flame-retardant polyolefin resin compositions obtained in Examples 1 to 5 had a high oxygen index, that is, excellent flame retardancy.
In particular, as shown in Examples 1 to 5, even in a small-diameter insulated wire having no structural flame retardancy, the LOI value is 3 or less.
If it is 0 or more, it can pass the JIS C 3005 60 ° inclined flame retardant test, which can be achieved by a combination of EEA and silicone rubber powder. On the other hand, the test sheets of the flame-retardant polyolefin resin compositions obtained in Comparative Examples 1 to 3 in which no silicone rubber powder was blended had a low oxygen index,
It was inferior in flame retardancy. Further, the test sheets of Examples 1 to 5 had the same tensile properties as the test sheets of Comparative Examples 1 to 3.

From these facts, the test sheets of the flame-retardant polyolefin resin compositions obtained in Examples 1 to 5
By incorporating silicone rubber powder, the flame retardancy is improved without lowering the tensile properties, and furthermore, by using an ethylene-ethyl acrylate copolymer, wires and cables that have no structural flame retardancy JI
It can be seen that it becomes possible to pass the SC 3005 60 ° inclined flame retardant test.

[0056]

According to the present invention, by mixing an ethylene-ethyl acrylate copolymer, a metal hydroxide and a silicone powder in specific amounts, a machine which can be suitably used as a coating material for electric wires and cables. Properties (for example,
A flame-retardant polyolefin resin composition having improved flame retardancy without lowering the breaking strength, tensile strength, elongation, etc.) can be obtained. Further, the electric wire / cable of the present invention
Since it is coated with the flame-retardant polyolefin resin composition, it has excellent mechanical properties and flame retardancy.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 3/44 H01B 3/44 FP 7/295 (C08L 23/08 // (C08L 23/08 83: 04) 83:04) H01B 7/34 B (72) Inventor Nozomi Fujita No. 8 Nishinocho, Higashikojima, Amagasaki City, Hyogo Prefecture Inside Mitsubishi Electric Wire Industry Co., Ltd. (72) Inventor Yoshiaki Ueda Nishinomachi, Higashikojima Island, Hyogo Prefecture No. 8 Inside Mitsubishi Electric Wire Industries Co., Ltd. (72) Kazuyuki Ogura Inventor Kazuyuki 8 Higashi-Mukojima Nishinomachi, Amagasaki City, Hyogo F-term (in reference) 4H028 AA10 AA12 AA42 AA49 AB04 BA04 BA06 4J002 BB071 BG041 CP052 CP092 CP142 CP162 DE076 DE086 DE146 FA082 FD136 GQ01 5G303 AA06 AB12 AB20 BA12 CA01 CA09 CB01 CB17 5G305 AA02 AA14 AB15 AB25 BA15 BA22 CA01 CA07 CA40 CA51 CC03 CD13 5G315 CA03 CB02 CB06 CC08 CD04 CD14 CD17

Claims (6)

[Claims] 1. A flame-retardant polyolefin resin composition comprising the following components: (A) 100 parts by weight of an ethylene-ethyl acrylate copolymer; (B) 50 parts by weight to 150 parts by weight of a metal hydroxide; And (C) 0.1 to 15 parts by weight of silicone powder. 2. The method according to claim 1, wherein the metal hydroxide is magnesium hydroxide,
The flame-retardant polyolefin resin composition according to claim 1, which is at least one selected from the group consisting of aluminum hydroxide and calcium hydroxide. 3. The flame-retardant polyolefin resin composition according to claim 1, wherein the silicone powder is at least one selected from the group consisting of silicone rubber powder having a functional group and silicone resin powder. 4. The silicone powder has an average particle size of 1 μm.
The flame-retardant polyolefin resin composition according to claim 1, which has a diameter of from m to 1000 m. 5. An electric wire coated with the flame-retardant polyolefin resin composition according to claim 1. 6. A cable coated with the flame-retardant polyolefin resin composition according to claim 1.