JP2007211105A - Flame-retardant thermoplastic resin composition and molded product thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant thermoplastic resin composition for a covering material of an electric wire that is excellent in both flame retardancy and abrasion resistance and causes no abrasion of a kneader or a molding machine. <P>SOLUTION: The flame-retardant thermoplastic resin composition comprises 100 pts.mass of a resin component comprised of 20-95 mass% of (A) a polypropylene resin, 1-30 mass% of (B) a polyolefin resin and/or a styrene copolymer modified with at least one selected from the group consisting of unsaturated carboxylic acids, derivatives thereof, (meth)acrylic acid and derivatives thereof, 0-80 mass% of (C) an ethylene-α-olefin copolymer and 0-20 mass% of (D) a copolymer of an aromatic vinyl compound with a conjugated diene compound and/or a hydrogenate thereof, 50-300 pts.mass of (E) a metal hydroxide and 1-30 pts.mass of (F) a spherical hard filler having a Mohs hardness of at least 7 by a 15-stage Mohs hardness meter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a flame retardant thermoplastic resin composition for a wire coating material. More specifically, it has excellent flame resistance and wear resistance, and does not elute heavy metal compounds or generate a large amount of smoke or corrosive gas at the time of disposal such as landfill and combustion. The present invention relates to a thermoplastic resin composition.

Insulated wires, cables, and cords used for internal and external wiring of electric / electronic devices are required to have various characteristics such as flame retardancy, heat resistance, and mechanical characteristics (for example, tensile characteristics and wear resistance). For this reason, polyvinyl chloride (PVC) compounds and polyolefin compounds containing halogen-based flame retardants containing bromine and chlorine atoms in the molecule were mainly used as coating materials used for these wiring materials. .

However, when they are burned, corrosive gas may be generated from the halogen compound contained in the coating material, and in recent years, the wiring material coated with a non-halogen flame retardant material that is free from the generation of halogen-based gas and the like. Consideration is being made.

Non-halogen flame retardant materials exhibit flame retardancy by incorporating a flame retardant containing no halogen into the resin. For example, ethylene / 1-butene copolymer, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer. Polymers, ethylene copolymers such as ethylene / ethyl acrylate copolymers, ethylene / propylene / diene terpolymers, and metal hydroxides (metal water such as aluminum hydroxide and magnesium hydroxide as flame retardants) Materials that are blended in large amounts (sometimes called Japanese products) have been proposed (for example, Patent Documents 1 and 2).

Standards such as flame retardancy, heat resistance, and mechanical properties (for example, tensile properties and wear resistance) required for wiring materials of electric / electronic devices are defined by UL, JIS, and the like. In particular, for flame retardancy, the test method varies according to the required level according to the application. For example, vertical flame test (VW-1) defined in UL 1581 (Reference Standard for Electrical Wires, Cables and Flexible Cords) (VW-1), JIS C 3005 (VW-1) Rubber and plastic insulated wire test method) and horizontal test and inclination test.

In addition, from the viewpoint of safety, strict standards for various physical properties other than the flame retardant standard are set for the wire coating material. In particular, thin insulated wires wired to automobiles and electronic devices are required to have high wear resistance against contact with other members during assembly, vibration during use, and the like. However, if a large amount of metal hydroxide is added to obtain the desired flame retardancy, the wear resistance is poor. Therefore, a material that maintains the target flame retardancy and has high wear resistance is desired.

On the other hand, it is generally known to add a hard filler to a resin in order to impart wear resistance (for example, Patent Documents 3 and 4). However, in the wire covering material, calcium carbonate is used as an extender, but no hard filler has been added to improve wear resistance. Hard fillers wear an apparatus such as a kneader during the production of a composition containing the hard filler, and also when an electric wire is produced by extruding a coating layer made of the above composition around a conductive wire, an extruder, particularly This is because the die is worn. Since the wear of dies and the like will inevitably interrupt production, the wear of dies and the like is a serious problem in the production of elongated articles such as electric wires.
JP 2001-316537 A JP 2003-160704 A JP 2005-152603 A JP-A-6-228362

An object of the present invention is to provide a non-halogen thermoplastic resin composition for a wire coating material that has excellent wear resistance while maintaining flame retardancy and does not wear a kneader or a molding machine.

This object could be achieved by adding a specific amount of a specific hard filler while adding a metal hydroxide as a flame retardant to the resin composition.

That is, the present invention
(1) (A) 20 to 95% by mass of a polypropylene resin,
(B) 1 to 30% by mass of a polyolefin resin and / or a styrene copolymer modified with at least one selected from the group consisting of an unsaturated carboxylic acid or a derivative thereof and (meth) acrylic acid or a derivative thereof,
(C) ethylene-α olefin copolymer 0-80% by mass, and (D) copolymer of aromatic vinyl compound and conjugated diene compound and / or hydrogenated product thereof 0-20% by mass.
100 parts by weight of a resin component containing, and (E) 50 to 300 parts by weight of a metal hydroxide and (F) 1 to 30 parts by weight of a spherical hard filler having a Mohs hardness of 7 or more according to a 15-stage Mohs hardness tester It is a flame retardant thermoplastic resin composition for a wire coating material.

Preferably, the present invention provides
(2) The flame retardant thermoplastic resin composition of (1), wherein the hard filler in component (F) is silica;
(3) The flame retardant thermoplastic resin composition of (1), wherein the hard filler in component (F) is alumina,
(4) The flame retardant thermoplastic resin composition according to any one of (1) to (3), further including 0.001 to 1 part by mass of an organic peroxide (G), and (5) (H) The flame-retardant thermoplastic resin composition according to (4), further including 0.003 to 2.5 parts by mass of a (meth) acrylate-based and / or allylic crosslinking aid.

  Moreover, this invention also provides the electric wire which has a coating layer which consists of a flame-retardant thermoplastic resin composition of any one of said (1)-(5).

The flame-retardant thermoplastic resin composition of the present invention has excellent flame resistance and wear resistance, and does not wear kneaders and molding machines. It is useful for manufacturing a wiring material for equipment, for example, a wire harness. In addition, since the flame retardant thermoplastic resin composition of the present invention is a non-halogen flame retardant material, at the time of disposal such as landfilling and combustion, elution of harmful heavy metal compounds, a large amount of smoke, harmful gas (corrosive gas) This is also environmentally preferable.

The present invention will be described in detail below.
First, each component of the flame-retardant thermoplastic resin composition of the present invention will be described.

(A) Polypropylene resin Component (A) includes homopolypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene and other small amounts of α-olefin (for example, 1- Butene, 1-hexene, 4-methyl-1-pentene, etc.). Here, the propylene-ethylene random copolymer refers to a propylene-based crystalline random copolymer, and the propylene-ethylene block copolymer refers to a crystalline polypropylene component (homopolypropylene, propylene-ethylene random copolymer). , A copolymer of propylene and other small amount of α-olefin) and a mixture of ethylene and α-olefin copolymer rubber component.

Component (A) preferably has an MFR (ASTM-D-1238, L condition, 230 ° C.) of 0.1 to 20 g / 10 min, from the viewpoint of moldability and wear resistance of the resin composition obtained. Preferably it is 0.2-5 g / 10min, More preferably, it is 0.3-2 g / 10min.

(B) Polyolefin resin in polyolefin resin and / or styrene copolymer component (B) modified with at least one selected from the group consisting of unsaturated carboxylic acid or derivative thereof and (meth) acrylic acid or derivative thereof As, for example, polyethylene (linear polyethylene, very low density polyethylene, high density polyethylene), polypropylene (homopolypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene and other small amounts of and a copolymer with an α-olefin (for example, a copolymer with 1-butene, 1-hexene, 4-methyl-1-pentene, etc.). Examples of the styrene copolymer include a styrene-ethylene / butene-butylene copolymer (SEBS), a styrene-ethylene / propylene / styrene copolymer (SEPS), and a styrene / ethylene / ethylene / propylene / styrene copolymer ( SEEPS), hydrogenated copolymers such as styrene-butadiene-butene-styrene copolymer (SBBS), styrene-butadiene-styrene copolymers (SBS), non-polymerized styrene-isoprene-styrene copolymers (SIS), etc. Examples thereof include hydrogenated copolymers. Among these, a hydrogenated copolymer is preferable.

Component (B) comprises the above polyolefin resin or styrene copolymer as an unsaturated carboxylic acid or derivative thereof (hereinafter referred to as unsaturated carboxylic acid (derivative)) and (meth) acrylic acid or derivative thereof (hereinafter referred to as These are modified with at least one selected from the group consisting of (meth) acrylic acid (derivative). Examples of the unsaturated carboxylic acid used for modification include maleic acid, itaconic acid, fumaric acid and the like, and examples of the unsaturated carboxylic acid derivative include maleic acid monoester, maleic acid diester, maleic anhydride, itaconic acid. Examples include monoesters, itaconic acid diesters, itaconic anhydride, fumaric acid monoesters, fumaric acid diesters, and fumaric anhydride. Examples of (meth) acrylic acid used for modification include acrylic acid and methacrylic acid, and examples of (meth) acrylic acid derivatives include acrylic acid esters and methacrylic acid esters.

The modification is performed, for example, by heating and kneading a polyolefin resin or a styrene copolymer in the presence of at least one selected from unsaturated carboxylic acid (derivative) and (meth) acrylic acid (derivative) and an organic peroxide. be able to. The amount of modification is not particularly limited. For example, when it is modified with maleic acid or (meth) acrylic acid, it is usually about 0.1 to 7% by mass.

A commercial item can also be used as a component (B), for example, Asahi Kasei Chemicals Corporation Tuftec M1911 (brand name, maleic anhydride modified SEBS) is mentioned.

The component (B) has an effect of alleviating a decrease in mechanical properties (tensile properties and wear resistance) due to a highly filled metal hydroxide and an effect of improving the wear resistance of the resin composition.

(C) Ethylene- [alpha] olefin copolymer Component (C) is an optional component. The component (C) is preferably a copolymer of ethylene and an α-olefin having 4 to 12 carbon atoms. Specific examples of the α-olefin include 1-butene, 1-hexene, 4-methyl-1 -Pentene, 1-octene, 1-decene, 1-dodecene and the like.

Specific examples of component (C) include polymerization in the presence of linear low density polyethylene (LLDPE), low density polyethylene (LDPE), very low density polyethylene (VLDPE), ethylene butene rubber (EBR) and metallocene catalyst. And ethylene-α-olefin copolymers. Among these, an ethylene-α-olefin copolymer polymerized in the presence of a metallocene catalyst is preferable. As the production method, known methods described in JP-A-6-306121, JP-A-7-500622 and the like can be used.

A commercially available product can also be used as the ethylene-α-olefin copolymer polymerized in the presence of the metallocene catalyst. Specific examples thereof include, for example, “AFFINITY” “ENGAGE” (trade name) manufactured by Dow Chemical, “Kernel” (trade name) manufactured by Nippon Polychem Co., Ltd., “Evolution” (trade name) manufactured by Sumitomo Mitsui Polyolefin Co., Ltd. ).

A metallocene catalyst has a single polymerization active site and has a high polymerization activity, and is also referred to as a Kaminsky catalyst. An ethylene-α-olefin copolymer synthesized using this catalyst has a molecular weight. The distribution and composition distribution are narrow.

Since the ethylene-α-olefin copolymer polymerized in the presence of such a metallocene catalyst has high tensile strength, tear strength, impact strength, etc., it is difficult to halogenate with a high content of metal hydrate. When used as a fuel material (wiring material coating material), there is an advantage that the deterioration of mechanical properties due to highly filled metal hydrate can be reduced.

On the other hand, when an ethylene-α-olefin copolymer polymerized using a metallocene-based catalyst is used, an increase in melt viscosity or a decrease in melt tension occurs compared to the case of using a normal ethylene-α-olefin copolymer. This causes a problem in moldability. In this regard, two peaks in the molecular weight distribution can be obtained by introducing long chain branching using asymmetric ligands as metallocene catalysts (Constrained Geometry Catalytic Technology) or connecting two polymerization vessels during polymerization. Some have improved the molding processability by making (Advanced PerformanceTerpolymer).

Component (C), in terms of flexibility and tensile elongation of the resulting composition is preferably density of 950 kg / m ³ or less, more preferably 945 kg / m ³ or less, particularly preferably 940 kg / m ³ or less It is. Further, the density, considering the wear resistance, preferably 880 kg / m ³ or more, more preferably 900 kg / m ³ or more, particularly preferably 920 kg / m ³ or more.

Further, the component (C) preferably has a melt flow rate (hereinafter referred to as MFR) (based on ASTM D-1238) of 0.5 to 30 g / 10 min.

(D) Copolymer of aromatic vinyl compound and conjugated diene compound and / or hydrogenated product thereof Component (D) is optionally used and is described below in (D-1) and (D- 2).

(D-1) Block copolymer of aromatic vinyl compound and conjugated diene compound and / or hydrogenated product thereof:
Component (D-1) is a block copolymer comprising at least two polymer blocks A mainly composed of an aromatic vinyl compound and at least one polymer block B mainly composed of a conjugated diene compound, It is a hydrogenated block copolymer obtained by hydrogenating a block copolymer. For example, an aromatic vinyl compound-conjugated diene compound block copolymer having a structure such as ABA, BABA, ABBABA, or the like and a hydrogenated product thereof.

The (hydrogenated) block copolymer (hereinafter, the (hydrogenated) block copolymer means a block copolymer and / or a hydrogenated block copolymer) is obtained by converting an aromatic vinyl compound to 5 to 5. 60% by weight, preferably 20 to 50% by weight.

The polymer block A mainly composed of an aromatic vinyl compound is preferably composed only of an aromatic vinyl compound, or a copolymer of a conjugated diene compound with an aromatic vinyl compound of 50% by weight or more, preferably 70% by weight or more. It is a block.

The polymer block B mainly composed of a conjugated diene compound is preferably composed of only a conjugated diene compound or a copolymer block of 50% by weight or more, preferably 70% by weight or more of an conjugated diene compound and an aromatic vinyl compound. is there.

In each of polymer block A and polymer block B, the distribution of the aromatic vinyl compound or conjugated diene compound in the molecular chain is random, tapered (in which the monomer component increases or decreases along the molecular chain), partly It may be a block or any combination thereof.

When there are two or more polymer blocks A or polymer blocks B, each may have the same structure or a different structure.

Examples of the aromatic vinyl compound constituting the (hydrogenated) block copolymer include styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-amino. One type or two or more types are selected from ethyl styrene, vinyl toluene, p-tert-butyl styrene and the like, and among them, styrene is preferable. Further, as the conjugated diene compound, for example, one or more kinds are selected from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., among which butadiene, isoprene, and these The combination of is preferable.

The bonding position of the conjugated diene compound in the polymer block B can be arbitrarily selected. In the butadiene block, the 1,2-bond is preferably 1% or more, more preferably 5% or more, still more preferably 10% or more, and the upper limit is preferably 95% or less, more preferably 80% or less, still more preferably. Is 75% or less.

The hydrogenation rate in the hydrogenated block copolymer can be arbitrarily selected. When improving the heat deterioration resistance and the like while maintaining the characteristics of the unhydrogenated block copolymer, it is preferable to hydrogenate the aliphatic double bond based on the conjugated diene to less than 85%, preferably less than 80%. Further, the ratio of 1,2-vinyl bond after hydrogenation to the amount of 1,2-vinyl bond before hydrogenation is preferably 0.5 to 12%, more preferably less than 10%.

In addition, when improving heat deterioration resistance and weather resistance, it is recommended to hydrogenate 80% or more, preferably 90% or more of the aliphatic double bond based on the conjugated diene. In the polyisoprene block, 70 to 100% by weight of isoprene is 1,4-bonded, and at least 90% of the aliphatic double bonds based on isoprene are hydrogenated.

The weight average molecular weight of the (hydrogenated) block copolymer used in the present invention is preferably 5,000 to 1,500,000, more preferably 10,000 to 550,000, still more preferably 50,000 to 400. , 000. The molecular weight distribution (ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn)) is preferably 10 or less, more preferably 5 or less, and more preferably 2 or less. The molecular structure of the hydrogenated block copolymer may be linear, branched, radial, or any combination thereof. In addition, the molecular weight in this specification is the value calculated | required by GPC on the basis of the polystyrene whose molecular weight is known. Therefore, the value is a relative value, not an absolute value, and may vary by about ± 30% depending on GPC conditions such as a reference sample, apparatus, and data processing method.

A number of methods have been proposed as methods for producing these (hydrogenated) block copolymers. As typical methods, for example, a lithium catalyst or a lithium catalyst or a method described in Japanese Patent Publication No. 40-23798 can be used. A block copolymer can be obtained by performing block polymerization in an inert solvent using a Ziegler type catalyst. Further, a hydrogenated block copolymer can be obtained by hydrogenating the block copolymer obtained by the above method in the presence of a hydrogenation catalyst in an inert solvent.

Specific examples of the above (hydrogenated) block copolymer include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene butene-styrene copolymer ( SEBS), styrene-ethylene / propylene-styrene copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene copolymer (SEEPS), partially hydrogenated styrene-butadiene-styrene copolymer (SBBS), and the like. be able to. In the present invention, the (hydrogenated) block copolymer may be used alone or in admixture of two or more.

(D-2) Random copolymer of aromatic vinyl compound and conjugated diene compound and / or hydrogenated product thereof:
Examples of the aromatic vinyl compound in the component (D-2) include styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethylstyrene, One or two or more types can be selected from vinyl toluene, p-tert-butyl styrene, etc. Among them, styrene is preferable. Further, as the conjugated diene compound, for example, one or two or more kinds are selected from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., among which butadiene, isoprene and These combinations are preferred.

The aromatic vinyl compound and the conjugated diene compound are randomly bonded, and the hydrogenated product of the random copolymer is one in which at least 90% of the aliphatic double bond based on the conjugated diene compound is hydrogenated. preferable.

Component (D-2) has a number average molecular weight of preferably 5,000 to 1,000,000, more preferably 10,000 to 350,000. Preferably, the value of polydispersity (Mw / Mn) is 10 or less, and the vinyl bond content such as 1,2-bond or 3,4-bond of the conjugated diene part is 5% or more, More preferably, it is 20 to 90%.

Specific examples of the component (D-2) include a styrene / butadiene random copolymer (SBR) and a hydrogenated styrene / butadiene random copolymer (HSBR). These may be used alone or in combination of two or more. Can be used in combination.

The flame-retardant thermoplastic resin composition of the present invention contains the components (A) to (D) as resin components. Component (A) to (D) in the resin component is blended in an amount of 20 to 95% by mass, preferably 25 to 90% by mass, more preferably 30 to 85% by mass, and component (B). Is 1 to 30% by mass, preferably 5 to 20% by mass, component (C) is 0 to 80% by mass, preferably 10 to 70% by mass, and component (D) is 0 to 0% by mass. 20% by mass, preferably 5 to 10% by mass.
When the amount of component (A) exceeds the above upper limit, it becomes hard, and the tensile elongation decreases, and when it is less than the lower limit, the wear resistance decreases. When the compounding amount of the component (B) exceeds the above upper limit, the extrusion characteristic of the electric wire is significantly lowered or the tensile elongation is significantly lowered. When it is less than the lower limit, the wear resistance is lowered. When the compounding amount of the component (C) exceeds the upper limit, the wear resistance is lowered. When the compounding amount of the component (D) exceeds the above upper limit, the wear resistance is lowered.

(E) Metal hydroxide Component (E) acts as a flame retardant, such as aluminum hydroxide, magnesium hydroxide, hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, hydrotalcite A compound having a hydroxyl group or water of crystallization such as these can be used alone or in combination of two or more. Of these metal hydroxides, aluminum hydroxide and magnesium hydroxide are preferred. The metal hydroxide may or may not be surface treated with a surface treatment agent. The surface treatment agent is preferably a silane coupling agent.

As silane coupling agents, vinyltrimethoxysilane, vinyltriethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, glycidoxypropylmethyldimethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxy Mercapto groups such as propyl coupling groups such as propyltriethoxysilane and methacryloxypropylmethyldimethoxysilane, silane coupling agents terminated with vinyl groups, (meth) acryloyl groups or epoxy groups, mercaptopropyltrimethoxysilane and mercaptopropyltriethoxysilane Coupling agent, aminopropyltriethoxysilane, aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltripp A crosslinkable silane coupling agent such as a silane coupling agent having an amino group, such as propyltrimethoxysilane and N- (β-aminoethyl) -γ-aminopropyltripropylmethyldimethoxysilane, is preferred. These silane coupling agents can be used alone or in combination of two or more.

Among such silane coupling agents, a silane coupling agent having an epoxy group, a vinyl group, a (meth) acryloyl group or an amino group at the terminal is preferable, and more preferably an epoxy group, a vinyl group or (meth) at the terminal. It has an acroyl group.

When the metal hydroxide is treated with the silane coupling agent, it is necessary to blend the silane coupling agent with the metal hydroxide in advance. At this time, the silane coupling agent is appropriately added in an amount sufficient for the surface treatment, and specifically, 0.2 to 2% by mass with respect to the metal hydroxide is preferable. The silane coupling agent may be a stock solution or may be diluted with a solvent.

The metal hydroxide that can be used in the present invention is commercially available. For example, “Kisuma 5” (trade name, manufactured by Kyowa Chemical Industry Co., Ltd.) can be used as surface-untreated magnesium hydroxide, and silane coupling. Examples of magnesium hydroxide surface-treated with an agent include “Kisuma 5L” and “Kisuma 5P” (both trade names, manufactured by Kyowa Chemical Industry Co., Ltd.).

In addition, magnesium hydroxide or aluminum hydroxide that has been partially pretreated with a fatty acid or a phosphate ester is used to add a surface using a silane coupling agent having a functional group such as a vinyl group or an epoxy group at the terminal. What has been processed can be used.

The compounding quantity of a component (E) is 50-300 mass parts with respect to 100 mass parts of resin components, Preferably, it is 60-250 mass parts. When the amount is more than the above upper limit, the tensile elongation and wear resistance of the obtained resin composition are remarkably lowered. If it is less than the lower limit, sufficient flame retardancy cannot be obtained.

(F) Spherical hard filler having a Mohs hardness of 7 or more The component (F) has an effect of remarkably improving the wear resistance. The hard filler used in the present invention has a Mohs hardness of 7 or more, preferably 9 or more as measured by a 15-stage Mohs hardness meter, and has a spherical shape. If the hardness of the hard filler is less than 7, sufficient wear resistance cannot be obtained.

The hard filler in the present invention has a spherical shape. In the case of a non-spherical shape, for example, an indeterminate shape obtained by pulverizing a bulk filler, a plate shape, a scale shape, or the like, sufficient wear resistance cannot be obtained. Needle-shaped ones have an effect of improving wear resistance, but the hardness of the filler is as high as 7 or more, which causes wear of the apparatus for kneading the resin composition and the extruder used for molding the resin composition. There is a problem. It has been found that hard fillers that give sufficient wear resistance and do not cause wear of the kneading apparatus or the extruder are limited to spherical shapes.

In the present invention, “spherical” means that the circularity is 0.8 to 1. The circularity is a degree representing how close to a true sphere, and the circularity of a true sphere is 1.

The circularity can be obtained by image-processing a photographed image of the filler by an electron microscope and calculating using the following formula.
Circularity = (4 · π · S) ^1/2 / L
S: Area of particle obtained by image processing L: Perimeter of particle

The hard filler in the present invention has a circularity calculated by using the above formula of 0.8 to 1, preferably 0.9 to 1, and more preferably 0.93 to 1.

The hard filler in the present invention preferably has an average particle size of 0.5 to 50 μm, more preferably 1 to 30 μm, in order to impart sufficient wear resistance.

Examples of the component (F) include silica, alumina, boron nitride and the like, and these can be used alone or in combination of two or more.

As a commercial item of a component (F), Excelica SE-5V (brand name, spherical silica) made from Tokuyama and Micron AX3-15 (brand name, spherical alumina) made from Micron are mentioned, for example.

The compounding quantity of a component (F) is 1-30 mass parts with respect to 100 mass parts of resin components, Preferably, it is 2-20 mass parts. When the upper limit is exceeded, the tensile elongation and wear resistance of the resulting resin composition are lowered. If it is less than the above lower limit, the abrasion resistance is insufficient.

(G) Organic peroxide Component (G) is an optional component and is added to improve heat resistance. Component (G) is particularly effective when added in the presence of component (C) and / or (D).
Examples of the component (G) include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2. , 5-Di (tert-butylperoxy) hexyne-3,1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane N-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxide Oxyisopropyl carbonate, diacetyl peroxide, Roy peroxide, such as tert- butyl cumyl peroxide and the like.
Of these, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di- in terms of odor, colorability, and scorch stability. (Tert-Butylperoxy) hexyne-3 is most preferred.

When blended, the amount of component (G) is in the range of 0.001 to 1.0 part by mass, preferably 0.01 to 0.5 part by mass, with respect to 100 parts by mass of the resin component. When the above upper limit is exceeded, the cross-linking proceeds so much that the extrusion processability is remarkably lowered.

(H) (Meth) acrylate-based and / or allyl-based crosslinking aid Component (H) is a crosslinking aid, and is optional for the flame-retardant thermoplastic resin composition of the present invention containing component (G). Added as an ingredient.

Here, the (meth) acrylate-based crosslinking aid refers to acrylate-based and methacrylate-based crosslinking aids. Specific examples include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate.
The allylic crosslinking aid includes those having an allyl group at the terminal, such as diallyl fumarate, diallyl phthalate, tetraallyloxyethane, and triallyl cyanurate.
The (meth) acrylate-based crosslinking aid is represented by the following formula, for example.

ここで、ＲはＨ又はＣＨ₃であり、ｎは１〜９の整数である。これらの中でも、ｎが１〜６の整数である（メタ）アクリレート系架橋助剤が好ましい。

Here, R is H or CH ₃ , and n is an integer of 1 to 9. Among these, a (meth) acrylate-based crosslinking aid in which n is an integer of 1 to 6 is preferable.

Specific examples include ethylene glycol diacrylate, triethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate. In particular, triethylene glycol dimethacrylate is preferred. This compound is easy to handle, has an organic peroxide solubilizing action, and acts as a dispersion aid for the organic peroxide, so that crosslinking can be made uniform and effective.

When blended, the amount of component (H) is preferably in the range of 0.003 to 2.5 parts by mass, more preferably 0.05 to 1.6 parts by mass, relative to 100 parts by mass of the resin component. . When the above upper limit is exceeded, the crosslinking proceeds too much and the dispersion of the crosslinked product becomes worse. The blending amount of the crosslinking aid (G) is preferably about 1.5 to 4.0 times the blending amount of the organic peroxide (G) by mass ratio.

In the flame-retardant thermoplastic resin composition of the present invention, various additives commonly used in electric wires, cables, cords, tubes, electric wire parts, sheets, etc., such as copper damage inhibitors, antioxidants, etc. An agent, a flame retardant (auxiliary) agent, a filler, a lubricant and the like can be appropriately blended within a range not impairing the object of the present invention. Antioxidants include amine-based antioxidants such as 4,4′-dioctyl diphenylamine, N, N′-diphenyl-p-phenylenediamine, and 2,2,4-trimethyl-1,2-dihydroquinoline polymer. Agent, pentaerythrityl-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate , 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and the like, bis (2-methyl-4- ( 3-n-alkylthiopropionyloxy) -5-tert-butylphenyl) sulfide, 2-mercaptoben ヅ imidazole and its zinc salt, pentaerythritol Lithol - tetrakis (3-lauryl - thiopropionate) and the like sulfur-based antioxidant such.

  The flame-retardant thermoplastic resin composition of the present invention can be obtained by melt-kneading the above components. The method of melt kneading is not particularly limited, and a generally known method can be used. For example, a single screw extruder, a twin screw extruder, a roll, a Banbury mixer, or various kneaders can be used. The melt kneading temperature is equal to or higher than the melting temperature of the resin component.

  The flame-retardant thermoplastic resin composition of the present invention is excellent in flame retardancy and abrasion resistance, and is useful as a coating material for wiring materials for automobiles and wiring materials for electric and electronic devices, for example, wire harnesses. When the flame-retardant thermoplastic resin composition of the present invention is used as a coating material for wiring materials, preferably, the flame-retardant thermoplastic resin composition of the present invention is used as a conductor using a general-purpose extrusion coating apparatus. It can be manufactured by extrusion coating around the periphery or the insulated wire. As a conductor, it can select arbitrarily from well-known things, such as an annealed copper single wire or a twisted wire, and can use it. Further, as the conductor, in addition to the bare wire, a tin plated one or an enamel-covered insulating layer may be used. The temperature of the extrusion coating apparatus is preferably about 200 ° C. at the cylinder portion and about 220 ° C. at the crosshead portion. In the present invention, the flame retardant thermoplastic resin composition does not contain a softening agent, but can be easily extrusion coated.

In the wiring member having a coating layer made of the flame retardant thermoplastic resin composition of the present invention, the thickness of the coating layer is not particularly limited, but is usually about 0.10 mm to 5 mm.

In addition, the flame-retardant thermoplastic resin composition of the present invention is preferably formed by extrusion-coating it to form a coating layer as it is. However, for the purpose of further improving heat resistance, the coating layer after extrusion is crosslinked. It is also possible to make it. However, when this crosslinking treatment is performed, it becomes difficult to reuse the coating layer as an extruded material.

As a method for carrying out the above crosslinking treatment, a conventional electron beam irradiation crosslinking method or chemical crosslinking method can be employed. In the case of the electron beam crosslinking method, the flame retardant thermoplastic resin composition of the present invention is extruded to form a coating layer, and then crosslinked by irradiating an electron beam by a conventional method. The dose of the electron beam is suitably 1 to 30 Mrad, and in order to perform crosslinking efficiently, a flame retardant thermoplastic resin composition constituting the coating layer is added to a methacrylate compound such as trimethylolpropane triacrylate, triallyl cyanide. Polyfunctional compounds such as allyl compounds such as nurate, maleimide compounds, and divinyl compounds may be blended as a crosslinking aid.
In the case of the chemical crosslinking method, an organic peroxide is blended with the flame retardant thermoplastic resin composition of the present invention as a crosslinking agent, extruded to form a coating layer, and then subjected to heat treatment and crosslinking by a conventional method. .

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. The evaluation methods and materials used in the examples and comparative examples are shown below.

Evaluation method (1) Specific gravity:
In accordance with JIS K 7112, a 1 mm thick press sheet was used as a test piece.
(2) Hardness:
In accordance with JIS K 7215, a 6 mm thick press sheet was used as a test piece. The hardness was D hardness and the load holding time was 5 seconds at room temperature.
(3) Tensile strength and tensile elongation:
In accordance with JIS K 7113, a 1 mm thick press sheet was punched into a No. 2 dumbbell-shaped test piece and used. The tensile speed was 200 mm / min at room temperature. The tensile elongation is desirably 100% or more.

(4) Abrasion resistance (scrape wear resistance):
A press sheet having a thickness of 0.5 mm was used as a test piece, which was clamped on a metal base, and a blade edge (scraping blade 0.125R, width 3 mm) subjected to a high load (14 N) on the test piece. ) Is vertically applied, and the edge is moved left and right to reciprocate (60 reciprocations / minute), so that the surface of the test piece is rubbed strongly. As the reciprocation continues, the test piece surface gradually wears due to friction between the edge and the test piece surface, and finally the edge penetrates the test piece. As a result, the metal surface under the test piece comes into contact with the edge. This contact is detected by an electrical short. The number of reciprocating motions until contact is read, and this is used as a measure of wear resistance. It shows that it is excellent in abrasion resistance, so that this frequency | count is large, and it is desirable that this frequency | count is 5000 times or more.
(5) Machine wear:
The material contact surface of the kneader used for the production of the flame retardant thermoplastic resin composition was visually compared with the material contact surface before use. The case where the change of color and abrasion were confirmed was marked with ◯, and the case where it was not confirmed was marked with ×.
(6) Heat resistance:
Using the same test piece as in (3) above, heat aging in a gear oven at 136 ° C., taking out the test piece several times after an arbitrary time while observing the state of the test piece, under the conditions of (3) above A tensile test was performed. The heat aging time required until the tensile elongation value (%) after heat aging reached 50% was measured and used as a measure of heat resistance.

(7) Circularity:
The shape of the hard filler was confirmed by an image taken with a scanning electron microscope. The circularity was obtained by processing the photographed image with an image analyzer and using the following equation. The number of samples for image processing was 200 or more.
Circularity = (4 · π · S) ^1/2 / L
S: Area of particle obtained by image processing L: Perimeter of particle

material
Ingredient (A):
(A-1) Propylene block copolymer: PB270A (manufactured by Sun Allomer Co.), crystalline propylene block copolymer, MFR 0.7 g / 10 min (230 ° C., load 21.18 N), Tm 168 ° C .;
(A-2) Homopropylene polymer: PX201N (manufactured by Sun Allomer), crystalline homopropylene polymer, MFR 0.6 g / 10 min (230 ° C., load 21.18 N), Tm 168 ° C .;
Ingredient (B):
Maleic anhydride modified SEBS: Tuftec M1911 (manufactured by Asahi Kasei Chemicals Corporation), maleic anhydride modified hydrogenated block copolymer, MFR 4 g / 10 min (200 ° C., load 49.04 N), styrene content: 30% by mass;
Ingredient (C):
LLDPE: Umerit 4040F (manufactured by Ube Industries), linear low density polyethylene using metallocene catalyst, density 0.937 g / cm ³ , MFR 4.0 g / 10 min (190 ° C., load 21.18 N);
Component (D):
SEPS: Septon 4033 (manufactured by Kuraray Co., Ltd.), hydrogenated block copolymer (SEPS (styrene-ethylene / propylene-styrene block copolymer)), styrene content: 30% by mass, number average molecular weight: 100,000, Weight average molecular weight: 130,000, hydrogenation rate: 90% or more;

Ingredient (E):
(E-1) Magnesium hydroxide: Kisuma 5L (manufactured by Kyowa Chemical Industry Co., Ltd.), magnesium hydroxide surface-treated with a silane coupling agent having a vinyl group at the terminal;
(E-2) Magnesium hydroxide: Kisuma 5 (manufactured by Kyowa Chemical Industry Co., Ltd.), surface untreated magnesium hydroxide;

Ingredient (F):
(F-1) Spherical silica: Excelica SE-5V (manufactured by Tokuyama Corporation), particle shape: spherical (circularity 0.96), average particle diameter 6 μm, specific surface area 2 m ² / g, Mohs hardness 7;
(F-2) Spherical alumina: Micron AX3-15 (manufactured by Micron Co., Ltd.), particle shape: spherical (circularity 0.97), average particle size 2.5-4.5 μm, specific surface area 0.65 m ² / g , Mohs hardness 12;
(F-3) Amorphous silica: Nip seal VN-3 (manufactured by Tosoh Silica Co., Ltd.), Particle shape: Amorphous, BET surface area 210 m ² / g, Mohs hardness 7;
(F-4) Scale-like boron nitride: HP-P1 (manufactured by Mizushima Alloy Iron Co., Ltd.), particle shape: scale-like, average particle diameter of 1-4 μm, specific surface area of 10-15 m ² / g, Mohs hardness 9;
(F-5) Amorphous calcium carbonate: NS-400 (manufactured by Nitto Flour Chemical Co., Ltd.), particle shape: amorphous, average particle diameter 1, 7 μm, Mohs hardness 3;

Ingredient (G):
Organic peroxide: Perhexa 25B (manufactured by NOF Corporation), 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1 minute half-life temperature 179 ° C .;
Ingredient (H):
Crosslinking assistant: NK ester IND (manufactured by Shin-Nakamura Chemical), triethylene glycol dimethacrylate;

Examples 1-7 and Comparative Examples 1-8
Using the components (parts by mass) shown in Tables 1 and 2, all the components were dry blended at room temperature, melt kneaded at 220 ° C. using a twin screw extruder with a screw diameter of 20 mm, and the strand cut type The resin composition pellets of Examples 1 to 7 and Comparative Examples 1 to 8 were obtained by cutting. The obtained pellets were made into a sheet with a roll, and further subjected to hot pressing to prepare a test piece, which was subjected to the evaluation test. The evaluation results are shown in Tables 1 and 2.

  As is clear from Table 1, the flame-retardant thermoplastic resin composition of the present invention had excellent wear resistance, and there was no wear of the kneader. Moreover, heat resistance improved by addition of arbitrary component (G).

  On the other hand, as is clear from Table 2, the composition of Comparative Example 1 not containing the component (F) was inferior in wear resistance. The composition of Comparative Example 2 in which the amount of component (F) was greater than the range of the present invention was inferior in tensile elongation and wear resistance. The composition of Comparative Example 3 in which the amount of component (A) was less than the range of the present invention was inferior in wear resistance. The compositions of Comparative Examples 4 and 5 in which the shape of the component (F) was not spherical were inferior in abrasion resistance, and abrasion of the kneader was observed. Component (F) The composition of Comparative Example 6 having a Mohs hardness of less than 7 was inferior in wear resistance. The composition of Comparative Example 7 in which the amount of component (E) was greater than the range of the present invention was inferior in tensile elongation and wear resistance. The composition of Comparative Example 8 containing no component (B) was inferior in wear resistance.

The flame-retardant thermoplastic resin composition of the present invention has excellent flame resistance and wear resistance, and does not wear kneaders and molding machines. It is useful for the manufacture of wiring materials for equipment.

Claims (6)

(A) 20-95% by mass of a polypropylene resin,
(B) 1 to 30% by mass of a polyolefin-based resin and / or a styrene copolymer modified with at least one selected from the group consisting of an unsaturated carboxylic acid or a derivative thereof and (meth) acrylic acid or a derivative thereof,
(C) ethylene-α olefin copolymer 0-80% by mass, and (D) copolymer of aromatic vinyl compound and conjugated diene compound and / or hydrogenated product thereof 0-20% by mass.
100 parts by weight of a resin component containing, and (E) 50 to 300 parts by weight of a metal hydroxide and (F) 1 to 30 parts by weight of a spherical hard filler having a Mohs hardness of 7 or more according to a 15-stage Mohs hardness tester A flame retardant thermoplastic resin composition for a wire coating material, characterized by comprising: The flame retardant thermoplastic resin composition according to claim 1, wherein the hard filler in component (F) is silica. The flame retardant thermoplastic resin composition according to claim 1, wherein the hard filler in component (F) is alumina. (G) The flame-retardant thermoplastic resin composition according to any one of claims 1 to 3, further comprising 0.001 to 1 part by mass of an organic peroxide. The flame retardant thermoplastic resin composition according to claim 4, further comprising 0.003 to 2.5 parts by mass of (H) (meth) acrylate-based and / or allylic crosslinking aid. The electric wire which has a coating | covering material which consists of a flame-retardant thermoplastic resin composition of any one of Claims 1-5.