JP2002179878A - Thermoplastic elastomer composition and flame- retardant sheath composed thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition excellent in flexibility, a mechanical strength, flame retardancy, heat resistance and processability of end cutting and a fllame-retardant sheath composed thereof. SOLUTION: This thermoplastic elastomer composition is obtained by compounding 100 pts.wt. of a hydrogenated block copolymer prepared by hydrogenating a block copolymer composed of a polymer block A mainly comprising at least one vinyl aromatic compound and a polymer block B mainly comprising at least one conjugated diene compound and having 30,000-300,000 number- average molecular weight, 5-200 pts.wt. of a polyphenylene ether resin which is a homopolymer and/or a copolymer having reduced viscosity (measured in 0.5 g/dl of chloroform solution at 30 deg.C) within the range of 0.15-0.70 and 50-900 pts.wt. of a metal hydrate and the frame-retardant sheath is composed of the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition comprising a specific hydrogenated block copolymer, a specific polyphenylene ether resin and a metal hydrate, and a flame-retardant sheath comprising the same. . Further, the present invention relates to a thermoplastic elastomer composition which is rich in flexibility, excellent in flame retardancy, excellent in mechanical strength, good in smoothness of extruded skin, and excellent in end cutting workability, and a flame retardant sheath comprising the same. .

[0002]

2. Description of the Related Art In recent years, cords and cables have been frequently used around us, from personal computers which have become remarkably widespread to audio equipment and OA equipment. Usually, these cords and cables are composed of an inner conducting wire for passing electric and optical signals, and a sheath of an outer covering portion. When the inner conductor is a plurality of insulated core wires, the sheath plays a role of bundling them. On the other hand, if the inner conductor is a single wire, insulate the core from the outside,
Protecting the human body from electricity and protecting electrical signals at the same time can be cited, and in that sense, a plastic or elastomeric soft material having excellent insulation properties is suitable. In recent years, optical communication technology using quartz fibers or plastic optical fiber cables (POF) has been developed, and the demand for elastomeric sheaths in this field has been increasing.

In fact, as a soft sheath material, soft polyvinyl chloride has been frequently used. The reason is that it is inexpensive, has excellent electrical insulation, has self-extinguishing flame retardancy,
Furthermore, it is firstly mentioned that it has good extrusion processability and mechanical properties, and excellent end cutting processability. In particular, the standards for flame retardancy required for the above-mentioned cords and cables are specified by UL and JIS, and the test method varies depending on the application. For example, the vertical combustion test (VW-1) specified in UL1581 or JIS
The horizontal test and the tilt test defined in C3005 are included. Since soft polyvinyl chloride contains a chlorine atom in the molecular chain, it exhibits extremely excellent flame retardancy and an extremely high oxygen index.

[0004] The term "end cutting workability" means that the end of the cord is cut only at the sheath portion with a bladed stripper to expose the conducting wire for the purpose of, for example, soldering the inner conducting wire. It means a series of workability, and what can be cut cleanly without extending the cut end is considered to be good. A sheath made of soft polyvinyl chloride has a characteristic that is extremely excellent in this end cutting workability. By the way, in recent years, market needs for polyvinyl chloride substitution have been increasing due to environmental problems. This sheath is no exception, and there is an increasing demand for the development of a material that can replace conventional soft polyvinyl chloride.

[0005] However, the development of alternative materials having flexibility, good extrusion processability, flame retardancy, and excellent end cutting properties, which are provided by the sheath made of soft polyvinyl chloride, is progressing rapidly. There was no reality. On the other hand, in recent years, a sheath made of a thermoplastic elastomer manufactured by using a dynamic crosslinking method has been on the market. Since the sheath is dynamically crosslinked, it is generally excellent in end cutting workability. However, since it is difficult to control the glossiness of the extruded skin of the sheath, there is a large restriction in design at present. Was.

[0006]

SUMMARY OF THE INVENTION The present invention provides a flame-retardant sheath comprising a thermoplastic elastomer composition comprising a combination of a specific hydrogenated block copolymer, a specific polyphenylene ether resin and a metal hydrate. In addition, it is particularly difficult to provide flexibility, good extrusion processability, flame retardancy and mechanical properties, and excellent end-cutting processability without relying on the dynamic crosslinking method. It is intended to provide a flammable sheath.

[0007]

Means for Solving the Problems In view of the above points, the present inventors have made intensive studies and as a result, have found that the following thermoplastic elastomer composition and a flame-retardant sheath comprising the same solve the above-mentioned problems. Heading, and led to the present invention. That is, the present invention provides: (A) At least one polymer block A mainly composed of a vinyl aromatic compound and at least one polymer block B mainly composed of a conjugated diene compound
100 parts by weight of a hydrogenated block copolymer having a number average molecular weight of 30,000 to 300,000 obtained by hydrogenating a block copolymer of the following formula (1):

[0008]

Embedded image

Wherein R1, R2, R3, and R4 are each selected from the group consisting of hydrogen, hydrocarbon, and substituted hydrocarbon groups, and may be the same or different from each other. (0.5 g / dl chloroform solution, measured at 30 ° C.) in the range of 0.15 to 0.70, 5 to 200 parts by weight of a polyphenylene ether resin which is a homopolymer and / or a copolymer, and (c) metal A thermoplastic elastomer composition comprising 50 to 900 parts by weight of a hydrate,

[0010] 2. Component (a) according to claim 1,
In addition to (b) and (c), (d) 5-300 parts by weight of a softener for non-aromatic rubber based on 100 parts by weight of component (a),
2. The thermoplastic elastomer composition according to claim 1, wherein (e) a hydrocarbon polymer in an amount of 5 to 200 parts by weight. A flame-retardant sheath obtained by molding the thermoplastic elastomer composition according to 1 or 2 above.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, the hydrogenated block copolymer used as the component (a) in the present invention will be described. The hydrogenated block copolymer used as the component (a) in the present invention contains at least 1
Block copolymer consisting of two, preferably two or more, polymer blocks A mainly composed of a vinyl aromatic compound and at least one polymer block B mainly composed of a conjugated diene compound, obtained by hydrogenating a block copolymer. Block copolymers, for example, AB, ABA, BABA, A-
BABA, BABAB, (AB) ₄
-Si, (B-A-B) _4- Si, (A-B) _4- S
n, (BAB) ₄ -Sn and the like.

The polymer block A mainly composed of a vinyl aromatic compound and the polymer block B mainly composed of a conjugated diene compound have a distribution of the vinyl aromatic compound or the conjugated diene compound in each polymer block. , Random or tapered (the monomer component increases or decreases along the molecular chain), or may be partially blocked or any combination thereof,
When there are two or more polymer blocks B,
Each polymer block may have the same structure or different structures. As used herein, the expression "predominantly" means that the corresponding monomer units account for at least 50% by weight, preferably at least 70%, of the polymer block.

Examples of the vinyl aromatic compound constituting the block copolymer of the present invention include, for example, styrene, α-methylstyrene, p-vinyltoluene, p-tert-butylstyrene (hereinafter the third is “t-” One or two or more of these can be selected, and styrene is particularly preferred. Further, as the conjugated diene compound, for example, one or more of butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like can be selected. Combinations are preferred. The polymer block B mainly composed of a conjugated diene compound before hydrogenation can be arbitrarily selected from microstructures in the block. For example, in the case of a polybutadiene block, a 1,2-vinyl bond structure is used. Is 20 to 70% by weight, preferably 25 to 50% by weight. In the polyisoprene block, 1,4-bonds are 80% by weight or more,
It is preferably at least 90% by weight.

The hydrogenated block copolymer used as the component (a) in the present invention has a number average molecular weight of 30,000 to 300,000,
More preferably, it is 80,000 to 200,000. By using a hydrogenated block copolymer having a number average molecular weight in the range of 30,000 to 300,000, it is possible to obtain a thermoplastic elastomer composition having an excellent balance between physical properties such as extrusion processability, mechanical strength, and heat resistance. Can be. Further, the molecular weight distribution of the hydrogenated block copolymer [weight average molecular weight (Mw) and number average molecular weight (Mn)]
(Mw / Mn)] is preferably 10 or less, more preferably 5 or less, and most preferably 2 or less. Mechanical strength of the sheath obtained when the molecular weight distribution exceeds 10,
Unsatisfactory heat resistance is not preferred.

The number average molecular weight and molecular weight distribution of these hydrogenated block copolymers can be easily determined by gel permeation chromatography using standard polystyrene. An example of a specific measurement method is as follows: Apparatus: PL-GPC-210 manufactured by Polymer Laboratory Column: PL gel 10 μm MIXED-B 300 × 7.5 mm 2 PL gel 10 μm GUARD 10 × 7.5 mm 1 Column temperature: 50 ° C Solvent: O-dichlorobenzene Sample concentration: 0.1% by weight After dissolution, filtration is performed with a filter.

The production method of these block copolymers is not limited as long as they have the above-mentioned structure. For example, a lithium catalyst can be prepared by the method described in JP-B-40-23798. Can be used to synthesize a vinyl aromatic compound-conjugated diene compound block copolymer in an inert solvent. Examples of a method for producing a vinyl aromatic compound-hydrogenated conjugated diene compound block copolymer exhibiting more preferable performance include, for example, JP-B-42-8704 and JP-B-43-66.
The method described in JP-A No. 36 may be used, but in applications requiring a high degree of weather resistance and heat aging resistance, use of a titanium-based hydrogenation catalyst is recommended.
No. 0147, JP-A-61-33132 and JP-A-62-207303. At least 80%, preferably at least 90%, of the aliphatic double bonds derived from the conjugated diene compound are hydrogenated, while less than 20%, preferably less than 10%, of the vinyl aromatic compound is hydrogenated. To be selected. The hydrogenation rate of the hydrogenated block copolymer can be easily known by infrared spectroscopy or nuclear magnetic resonance analysis.

Next, the polyphenylene ether resin used as the component (b) of the present invention will be described. The polyphenylene ether resin used as the component (b) of the present invention is an essential component for imparting end-cutting workability of the obtained flame-retardant sheath, and further has an improved heat resistance and a flame-retardant auxiliary agent. Plays a role. The component (b) has a bonding unit represented by the following formula (1).

[0018]

Embedded image

(Where R1, R2, R3, and R4 are each selected from the group consisting of hydrogen, hydrocarbon, and substituted hydrocarbon groups, and may be the same or different from each other), and have a reduced viscosity. (0.5 g / dl chloroform solution, measured at 30 ° C.) in the range of 0.15 to 0.70, preferably 0.20 to 0.60 is used.
Known polyphenylene ether resins can be used. Specific examples include poly (2,6-dimethyl-1,4-phenylene ether) and poly (2-methyl-
6-ethyl-1,4-phenylene ether), poly (2,6-diphenyl-1,4-phenylene ether), poly (2-methyl-6-phenyl-1,4-phenylene ether), poly (2,6-phenyl-1,4-phenylene ether) 6-dichloro-1,4-
Phenylene ether) and the like, and 2,6-dimethylphenol and other phenols (for example, 2,3
Polyphenylene ether copolymers such as copolymers with 6-trimethylphenol and 2-methyl-6-butylphenol) are also included. Among them, poly (2,6-dimethyl-1,4-phenylene ether), 2,6-dimethylphenol and 2,3,6-trimethylphenol are preferable, and poly (2,6-dimethyl-1,4-phenylene) is more preferable. Ether) is more preferred.

The reduced viscosity (0.5 g / dl chloroform solution, measured at 30 ° C.) of the above polyphenylene ether resin is preferably in the range of 0.15 to 0.70,
More preferably, it is in the range of 0.20 to 0.60. The amount of component (b) is based on 100 parts by weight of component (a).
It is possible to select from 5 to 200 parts by weight.
If the amount is less than 5 parts by weight, the heat resistance and the end cutting workability of the sheath as effects of adding the polyphenylene ether resin are not sufficiently imparted, which is not preferable. When the amount exceeds 200 parts by weight, the hardness of the obtained composition increases, and the flexibility of the sheath itself is impaired.
Not preferred. Furthermore, since the sheath cutting workability reaches a peak, it is not necessary to mix more than 200 parts.

A more preferred amount is 20 to 200 parts by weight, most preferably 35 to 150 parts by weight, per 100 parts by weight of the hydrogenated block copolymer (a). Next, the metal hydrate used as the component (c) of the present invention will be described. The metal hydrate used in the present invention is not particularly limited as long as it is a metal compound having a hydroxyl group or water of crystallization, but examples of preferably used metal hydrates include calcium hydroxide, aluminum hydroxide, Compounds such as magnesium hydroxide, aluminum silicate hydrate, magnesium silicate hydrate and hydrotalcite can be used alone or in combination of two or more.

Further, those obtained by subjecting a metal hydrate to a surface treatment with a fatty acid, a silane coupling agent or the like can be preferably used. By using these surface-treated metal hydrates, compared to the case of using the non-treated product, since an excellent improvement effect such as mechanical properties and smoothness of extruded skin appears, it is more preferably used. Can be The above metal hydrates can be easily obtained from the market, for example,
Kisuma 5 (magnesium hydroxide; no surface treatment), Kisuma 5A (magnesium hydroxide; surface treated with a fatty acid), Kisuma 5PH (magnesium hydroxide; surface treated with a silane coupling agent), etc. manufactured by Kyowa Chemical Industry are suitably used. Can be

The amount of the component (c) of the present invention is as follows:
It is 50 to 900 parts by weight based on 100 parts by weight of the component (a). If it is less than 50 parts, a sufficient flame retarding effect cannot be obtained,
If the amount exceeds 900 parts, the flame retardant effect is exhibited, but the mechanical strength is remarkably reduced, and the smoothness and flexibility of the extruded skin of the obtained sheath may be unfavorably deteriorated. A more preferred addition amount of the component (c) is 100 to 700 parts by weight, most preferably 150 to 700 parts by weight.
６００600 parts by weight.

Further, if necessary, more effective flame retardancy can be exhibited by using a phosphoric acid ester compound or a phosphorus compound represented by an inorganic phosphate. Specific examples include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tris (halopropyl) phosphate,
Tris (haloethyl) phosphate, ammonium polyphosphate, phosphonitriles chloride derivatives, vinylphosphonates, allylphosphonates, red phosphorus and the like.

On the other hand, the use of a halogen-based flame retardant is not limited in the present invention, but it is desirable to avoid using it in view of recent environmental problems and adverse effects. A non-aromatic rubber softener can be preferably added to the thermoplastic elastomer composition and the flame-retardant sheath of the present invention. The non-aromatic rubber softener is a component useful not only for imparting flexibility and processability to the obtained composition, but also for improving economic efficiency. The non-aromatic rubber softener used in the present invention is a generally known rubber oil classified into paraffinic and naphthenic types. Among them, paraffinic oils are preferable, and among paraffinic oils, those having an aromatic ring component of 5% or less are most preferable. The amount of the hydrocarbon oil to be used should be kept within a range that does not impair the physical properties of the obtained thermoplastic elastomer composition, but as a rough guide, 5 to 300 parts by weight based on 100 parts by weight of the hydrogenated block copolymer. And more preferably 30 to 150 parts by weight.

Further, a hydrocarbon polymer can be preferably added to the thermoplastic elastomer composition and the flame-retardant sheath of the present invention. The “hydrocarbon polymer” referred to herein is defined as a polymer whose constituent elements consist only of carbon and hydrogen. Hydrocarbon polymers are very useful for improving the moldability and mechanical strength of the thermoplastic elastomer composition of the present invention. Examples of preferably used hydrocarbon polymers include homopolymers such as low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ultra-high-molecular-weight polyethylene, polypropylene, polybutene, and polystyrene resin, or ethylene and propylene, And random or block copolymers obtained by combining two or more structural units arbitrarily selected from α-olefins such as -butene, 1-hexene and 1-octene. One of these may be used alone, or a plurality of hydrocarbon polymers may be used in combination at an arbitrary ratio. It should be noted that the amount of the hydrocarbon polymer used should be kept within a range that does not impair the flexibility of the obtained flame-retardant sheath. A suitable addition amount is 5 to 200 parts by weight, more preferably 30 to 150 parts by weight, based on 100 parts by weight of the hydrogenated block copolymer as the component (a).

Among them, the most preferred hydrocarbon polymer is polypropylene (both homo, block and random). In addition, polystyrene alone having good compatibility with the polyphenylene ether resin as the component (b) of the present invention is used. It is also possible to use a styrene resin such as a polymer together,
It is preferable in terms of improving the productivity of the thermoplastic elastomer composition of the present invention. In the thermoplastic elastomer composition of the present invention, a part of the composition can be partially or completely crosslinked using an organic peroxide or the like. By cross-linking, it is possible to further improve the mechanical strength and heat resistance of the obtained sheath. However, the terminal cutting workability already has sufficient characteristics, and rather, there is a restriction in terms of design such as hardly giving a glossy feeling.

The thermoplastic elastomer composition constituting the flame-retardant sheath of the present invention has a melt flow rate of 0.01
-100 (g / 10 minutes; conforming to ISO R1133). More preferably, 0.01 to 50
And most preferably 0.01 to 5. This range is particularly desirable because sheaths are generally manufactured by extrusion. The thermoplastic elastomer composition of the present invention may further contain, if necessary, a flame retardant (auxiliary) agent represented by a blocking inhibitor, a lubricant, silicone oil, a phosphate compound, a pigment, carbon Black, an inorganic filler, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, and the like can be contained. In particular, the use of a hindered phenol-based and / or phosphite-based antioxidant is recommended because the processing temperature is necessarily high because the component (b) is essential.

Generally, as a method for producing the thermoplastic elastomer composition of the present invention, these compounds are dry-blended using a mixer such as a Henschel mixer, a tumbler or a ribbon blender before melt-kneading. Then, the mixture is melt-kneaded to obtain a homogeneous composition. Any method known in the art may be used to blend the polymer components and additives. In order to obtain the most homogeneous blend, there is a method of melt-kneading using various kinds of kneading machines such as a mixing roll, a kneader, a Banbury mixer, and a single-screw extruder or a twin-screw extruder which are usually used. desirable. Among them, a method using a twin-screw extruder is most preferable.

The flame-retardant sheath comprising the thermoplastic elastomer composition of the present invention has good smoothness on the surface of the extruded surface, flexibility, flame retardancy, mechanical strength and heat resistance. It has excellent sheath cutting workability comparable to vinyl, and can be used for a wide variety of cords and cables. Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In these examples and comparative examples, the test methods used for various evaluation methods are as follows.

(1) Melt flow rate 230 ° C., 2.16 kg in accordance with ISO R1133
It evaluated in f. (2) Flexibility Using a 1/4 inch thick test piece, ASTM D790
The value of the flexural modulus [MPa] obtained by measuring in an atmosphere at 23 ° C. according to the above was used as an index of flexibility. (3) Tensile breaking strength [MPa] JIS K6251-93, JIS No. 3 dumbbell, tensile speed was 500 mm / min, and a sample was punched out from a 2 mm thick press sheet, and the measurement was performed in an atmosphere of 23 ° C.

(4) Oxygen Index The oxygen index (OI) defined by JIS K7201 as an index of the flame retardancy was replaced with the evaluation of the flame retardancy. (5) Smoothness of Extruded Skin A sheath was actually formed, and the smoothness of the skin was evaluated according to the following scale. ：: Excellent. Both gloss and matting are possible under extrusion molding conditions. ×: The surface state is rough. It is rough.

(6) Heat resistance The sheath portion obtained by removing the core wire from the molded plastic optical fiber (cable) (hereinafter referred to as “POF”) is wound around a 15 cm diameter cylinder five times at 80 ° C.
Heated for 24 hours. After the test, the remaining degree of the curl of the sheath was evaluated. ：: No winding habit remains. ：: Some curl remains. X: The curl remains completely.

(7) End-cutting workability The end portion of the sheath of the cord extruded together with the conductive wire is stripped (VESSEL 3000) as a dedicated tool.
The cutting process was performed using C). The evaluation criteria at that time were as follows. A: Extremely good end-cutting processability is shown. ○: slightly increased, but no problem. X: Cutting workability is not possible. The sheath end is extended and cannot be cut.

The following components were used. Component (a): Component (a-1): having a structure of ABA, number average molecular weight 62,000, molecular weight distribution 1.08, bound styrene amount 19% by weight, 1,4 of polybutadiene part before hydrogenation. 2-
A hydrogenated block copolymer of a styrene / butadiene block copolymer having a vinyl bond content of 35% by weight and a hydrogenation rate of the polybutadiene portion of 99% was synthesized by the method described in JP-A-60-220147. (A-1) was obtained.

Component (a-2): having the structure of ABA, having a number average molecular weight of 80000, a molecular weight distribution of 1.10, an amount of bound styrene of 28% by weight, and 1,4 of the polyisoprene part before hydrogenation. A binding amount of 94% by weight and a 3,4-binding amount of 6
A hydrogenated block copolymer of a styrene / isoprene block copolymer having a hydrogenation rate of 99% by weight in a polyisoprene part was synthesized by the method described in JP-A-60-220147. ) Got.

Component (a-3): having the structure of BABA, number average molecular weight of 170,000 and molecular weight distribution of 1.2
5. A hydrogenated block copolymer of a styrene / butadiene block copolymer having a bound styrene content of 35% by weight, a 1,2-vinyl bond content of the polybutadiene portion before hydrogenation of 38% by weight, and a hydrogenation rate of the polybutadiene portion of 99%. Coalescence
Synthesized by the method described in -220147
The component (a-3) was obtained.

Component (b): Poly (2,6-dimethyl-1,4-phenylene) ether (reduced viscosity: 0.56) was synthesized as a polyphenylene ether resin. Component (c): Kisuma 5PH manufactured by Kyowa Chemical Industry Co., Ltd. (trade name; magnesium hydroxide surface-treated with a silane coupling agent) Component (d): Diana Process Oil PW manufactured by Idemitsu Kosan Co., Ltd.
-380 (paraffinic process oil, kinematic viscosity; 38
1.6 cst (40 ° C.), 30.1 cst (10
C), ring analysis; CN = 27%, CP = 73%).

Component (e): Component (e-1): Polypropylene sun allomer PB370A (block type with ethylene) manufactured by Montell S.D. Sunrise, MFR: 1.3 (230)
Component (e-2): Ethylene octene-1 copolymer Engage 8180 MFR: 0.5 (190 ° C, 2.16 kgf) manufactured by Dupont Dow Elastomers.
16 kgf) Density: 0.863 Component (e-3): Polystyrene manufactured by A & M Styrene A & M Polystyrene G9305 (GP
PS type) MFR: 1.5 (200 ° C, 5kgf)

Component (f): Red phosphorus Novacwell ST100 (trade name) manufactured by Rin Kagaku Kogyo Co., Ltd. Component (g): Phosphorus antioxidant Irgafos 168 (trade name; chemical name: Tris (Ciba Specialty Chemicals)) 2,4
-Di-t-butylphenyl) phosphite)

[0041]

Examples 1 to 13 and Comparative Examples 1 to 4 Each of the essential components (a), (b) and (c), and optionally (e-
1) to (e-3), (f), and (g) were uniformly dry-blended in accordance with the respective blending amounts shown in Table 1, and then charged into a hopper, in the same direction with a diameter of 40 mm and L / D = 47. Melt kneading was performed with a twin screw extruder at a cylinder temperature of 270 ° C. The rubber softener of the component (d) was added by liquid addition at an intermediate point of the extruder. Thus, each of the thermoplastic elastomer compositions was obtained, and the respective test examples were used to obtain each of the examples and the comparative examples.

Using the obtained thermoplastic elastomer composition, a cord provided with a flame-retardant sheath having the following specifications was manufactured, and the end cutting workability was evaluated. Core lead wire: POF made of polymethyl methacrylate (PMMA resin) is used. 1mm in diameter. Sheath: The thermoplastic elastomer compositions shown in the following Examples and Comparative Examples were used. 2mm outside diameter. Extrusion molding machine: Extrusion coating device manufactured by Miba Seisakusho Co., Ltd. Both the conductor and the thermoplastic elastomer composition are supplied, the covering conductor is drawn out from a die, and the automatic constant-speed take-off machine is used at 10 m / min.
The production was carried out at the following speed. Table 1 shows the respective compositions of the obtained thermoplastic elastomer composition and the results of the evaluation items of the flame-retardant sheath obtained by molding the composition.

[0043]

[Table 1]

It is clear that the thermoplastic elastomer composition and the flame-retardant sheath of the present invention are all excellent in flexibility, mechanical strength, flame retardancy and end-cut workability. On the other hand, it is clear that the thermoplastic elastomer composition and the flame-retardant sheath other than the present invention shown in the comparative examples are inferior in any of flexibility, flame retardancy, and end-cut workability.

[0045]

The thermoplastic elastomer composition and the flame-retardant sheath of the present invention have excellent end-cutting workability without relying on dynamic crosslinking in addition to flexibility, mechanical strength, flame retardancy and heat resistance. Since it is expressed, it can be suitably used as a covering material for various cords and cables, and is particularly suitable as a substitute material for soft polyvinyl chloride, and therefore has an extremely large industrial value.

Claims (4)

[Claims] 1. A block copolymer comprising (a) at least one polymer block A mainly composed of a vinyl aromatic compound and at least one polymer block B mainly composed of a conjugated diene compound is hydrogenated. 100 parts by weight of the hydrogenated block copolymer having a number average molecular weight of 30,000 to 300,000 added and (b) a bonding unit represented by the following formula (1): (Where R1, R2, R3, and R4 are each selected from the group consisting of hydrogen, hydrocarbon, and substituted hydrocarbon groups, and may be the same or different from each other). 5 g / dl chloroform solution, 30
C) (measured in ° C) is in the range of 0.15 to 0.70, a homopolymer and / or a copolymer of 5 to 200 parts by weight of a polyphenylene ether resin, and (c) a metal hydrate of 50 to 900.
Parts by weight of a thermoplastic elastomer composition. 2. The component (a), (b) according to claim 1,
In addition to (c), (d) based on 100 parts by weight of component (a)
The thermoplastic elastomer composition according to claim 1, wherein 5 to 300 parts by weight of a softener for a non-aromatic rubber and 5 to 200 parts by weight of (e) a hydrocarbon polymer are blended. 3. A block copolymer comprising (a) at least one polymer block A mainly composed of a vinyl aromatic compound and at least one polymer block B mainly composed of a conjugated diene compound, is hydrogenated. 100 parts by weight of the hydrogenated block copolymer having a number average molecular weight of 30,000 to 300,000 added and (b) a bonding unit represented by the following formula (1): (Where R1, R2, R3, and R4 are each selected from the group consisting of hydrogen, hydrocarbon, and substituted hydrocarbon groups, and may be the same or different from each other). 5 g / dl chloroform solution, 30
C.) in the range of 0.15 to 0.70, and 5 to 200 parts by weight of a polyphenylene ether resin which is a homopolymer and / or a copolymer;
A flame-retardant sheath comprising a thermoplastic elastomer composition containing 900 parts by weight. 4. The component (a), (b) according to claim 3,
In addition to (c), (d) based on 100 parts by weight of component (a)
The flame retardant composition according to claim 3, comprising a thermoplastic elastomer composition comprising 5 to 300 parts by weight of a softener for a non-aromatic rubber and 5 to 200 parts by weight of (e) a hydrocarbon polymer. sheath.