JP6098497B2 - LAN cable using non-halogen flame retardant resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a LAN cable using a non-halogen flame retardant resin composition having a low environmental load and excellent flexibility and low friction as a sheath, and particularly the adhesion between cables when drawn from a bobbin or a box. Therefore, the present invention relates to a LAN cable excellent in handling work such as wiring workability.

  With the advent of an advanced information society, the role played by networks centered on computer systems has become increasingly important. LAN cables used for LAN (Local Area Network) construction are widely used from ordinary homes to corporate offices due to the spread of personal computers and broadband lines.

  Conventionally, polyvinyl chloride, which is a halogen-containing material, has been used as a sheath material for LAN cables. However, due to the recent worldwide increase in activities for environmental conservation, the spread of materials that do not generate toxic gas at the time of combustion and have little environmental pollution at the time of disposal has been rapidly progressing.

  A general material such as this is a composition in which a halogen-containing material is not included, and a non-halogen flame retardant such as a metal hydroxide is mixed with a base polymer such as a crystalline polyolefin-based resin. It is characterized by being considerably harder than

  However, in an office where a network environment is maintained, it is necessary to lay a large amount of LAN cables in a limited space such as a cable rack. At that time, since the sheath material of the LAN cable coated with the non-halogen flame retardant resin composition is hard, there is a problem that winding is difficult at the time of shipment or use, wiring is difficult, and work efficiency is lowered. . In addition, after laying the cable, when a new cable is additionally wired, or when a specific cable needs to be pulled out due to an abnormality or inspection, the cable sheath is inferior, and a new cable cannot be additionally wired, or There was a problem that a specific cable could not be pulled out.

  Therefore, Patent Document 1 proposes a cable using a non-halogen flame retardant resin composition having a base polymer of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 30% by mass or more and a crystalline polyolefin resin as a sheath. ing. The resin composition of this cable has excellent flexibility and low friction properties, and was suitable as a sheath material for LAN cables having excellent wiring workability.

JP 2011-195831 A

  On the other hand, there are cases where LAN cables are laid in large quantities in a limited space as described above, and there is a demand for reducing the diameter of LAN cables in order to make maximum use of the space.

  However, it has been found that if the sheath thickness is reduced in order to reduce the outer diameter of the cable, problems arise in that the slipperiness decreases and the sheaths adhere to each other in a bobbin or a shipping box.

Accordingly, the object of the present invention is to provide excellent flexibility and low friction even when the sheath thickness is reduced and the cable diameter is reduced, and the cables do not adhere to each other. It is providing the LAN cable using the non-halogen flame-retardant resin composition which was excellent in handling property.

In order to achieve the above object, according to the present invention, the following LAN cable is provided.

[1] A LAN cable having a sheath covering the outer periphery of a cable core , wherein the cable core has a configuration in which a plurality of electric wires are twisted together, and the sheath has (A) component: vinyl acetate content. Among 100 parts by mass of the base polymer containing 14 to 29% by mass of ethylene-vinyl acetate copolymer and (B) component: crystalline polyolefin resin, the component (A) is 40 to 80 parts by mass, (C) component: 30 to 150 parts by mass of metal hydroxide, (D) component: 1 to 10 parts by mass of acrylic compound, and (E) component: fatty acid amide compound with respect to 100 parts by mass of the base polymer. the containing 0.01 to 2 parts by weight, the component (a) consists of non-halogen flame retardant resin composition is silane crosslinked, the thickness of the sheath, Ri 0.2~0.45mm der, The cave LAN cable twist lay of the core characterized in that it is a structure that stand out on the sheath surface.
[2] The LAN cable according to [1], wherein a dynamic friction coefficient between the same cables conforming to JIS K7125 is 0.7 or less.
[3] The LAN cable according to [1] or [2], wherein the component (B) is 60 to 20 parts by mass of 100 parts by mass of the base polymer.

According to the present invention, even when the sheath coating thickness is reduced and the cable diameter is reduced, the cable has excellent flexibility and low friction, and the cables do not adhere to each other. A LAN cable using a non-halogen flame retardant resin composition having excellent properties is provided.

It is a cross-sectional view of the cable according to the first embodiment of the present invention. It is a cross-sectional view of the cable which concerns on the 2nd Embodiment of this invention. It is a cross-sectional view of the cable which concerns on the 3rd Embodiment of this invention. It is a cross-sectional view of the cable which concerns on the 4th Embodiment of this invention. It is the schematic which shows the test method of the drawability of the cable which concerns on this embodiment.

In order to achieve the above object, the present inventors have excellent flexibility and low friction properties while maintaining various physical properties such as mechanical strength and flame retardancy of conventional non-halogen flame retardant resin compositions, Has intensively studied the resin composition and cross-linking method for realizing low adhesion between materials, the type and amount of additives, and the thickness of the sheath. As a result, the following LAN cable was obtained.

That, LAN cable according to the embodiment of the present invention, there is provided a LAN cable with a sheath covering the outer periphery of the cable core, said cable core is twisted configure multiple wires, said sheath, (A) Component: Among 100 parts by mass of a base polymer containing an ethylene-vinyl acetate copolymer having a vinyl acetate content of 14 to 29% by mass and (B) component: a crystalline polyolefin-based resin, the (A) The component is 40 to 80 parts by mass, and (C) component: 30 to 150 parts by mass of the metal hydroxide and (D) component: 1 to 10 parts by mass of the acrylic compound with respect to 100 parts by mass of the base polymer. Component (E): 0.01 to 2 parts by mass of a fatty acid amide compound, and the component (A) comprises a non-halogen flame retardant resin composition crosslinked with silane, and the thickness of the sheath But, 0.2～0.45Mm der is, twist lay of the cable cores Ru structure der stand out on the sheath surface. In addition, as shown in FIG. 4 described later, a pressing tape or the like may be provided between the cable core and the sheath.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a cross-sectional view of the cable according to the first embodiment. On the outer periphery of a cable core in which four pairs of twisted wires obtained by twisting two conductors 1 and two wires covered with an insulator 2 are twisted. 1 shows a cable 10 in which a sheath 3 made of a non-halogen flame retardant resin composition is extrusion coated.

  The conductor 1 is made of a general-purpose material such as pure copper or tin-plated copper. The insulator 2 is preferably made of a non-halogen flame retardant resin composition. The thickness of the insulator 2 is not particularly limited, but is preferably 0.05 to 0.5 mm. The insulator 2 may be a single layer or a multilayer, but is preferably a single layer.

  FIG. 2 is a cross-sectional view of the cable according to the second embodiment. Four pairs of twisted wires in which two conductors 1 are covered with an insulator 2 are twisted, and independent by cross-shaped interpositions 4. A cable 20 is shown in which a sheath 3 made of a non-halogen flame retardant resin composition is extrusion coated on the outer periphery of the cable core. A general-purpose material can be used for the interposition 4.

  FIG. 3 is a cross-sectional view of the cable according to the third embodiment. On the outer periphery of a cable core in which four pairs of twisted wires obtained by twisting two conductors 1 covered with an insulator 2 are twisted. A cable 30 is shown in which a pressing tape 5 and a shield 6 are wound in order, and the outer periphery of the pressing tape 5 and a sheath 3 made of a non-halogen flame retardant resin composition are extrusion coated. A ground line 7 is provided between the tape 5 and the shield 6.

  FIG. 4 is a cross-sectional view of a cable according to the fourth embodiment, in which a plurality of cables 10 shown in FIG. 1 (six in the drawing) are twisted together with a circular section 14 disposed in the center. A cable 40 is shown in which a pressing tape 5 is wound around the outer periphery of the core, and the outer periphery of the sheath 3 made of a non-halogen flame retardant resin composition is extrusion coated. A general-purpose material can be used for the interposition 14.

[Non-halogen flame retardant resin composition constituting sheath 3]
Since the non-halogen flame retardant resin composition constituting the sheath 3 contains a large amount of a soft ethylene-vinyl acetate copolymer, it is more flexible than a conventional non-halogen flame retardant resin composition mainly composed of a crystalline polyolefin resin. It has the characteristic that it is excellent in nature. Further, the higher the vinyl acetate content of the ethylene-vinyl acetate copolymer, the lower the crystallinity and the better the flexibility, but the materials tend to stick together. Therefore, the optimum vinyl acetate content that can achieve both flexibility and low adhesiveness was investigated. As a result, the content of vinyl acetate is 14 to 29% by mass, and only the ethylene-vinyl acetate copolymer is selectively cross-linked so that the flexibility of the cables can be reduced without reducing the flexibility of the cables. It was found that even if the area increases, it does not stick.

  Moreover, by adding an appropriate amount of an acrylic compound, surface smoothness during extrusion is improved, and by adding an appropriate amount of a fatty acid amide compound, a low friction film is formed on the smooth surface. It became possible to obtain a material with low friction.

  Furthermore, it became clear that problems, such as adhesiveness, appeared remarkably by reducing the coating thickness of the conventional sheath from 0.5 mm to 0.45 mm. This is because when the sheath coating thickness is thinner than 0.45 mm, the cable core twisted together with the polyethylene insulated wires rises on the surface of the sheath, thereby increasing the contact area between the cable sheaths as compared with the conventional cable. This is probably because of this.

  That is, since the above materials have excellent flexibility and low friction properties, and the adhesiveness between the materials is low, the sheath of a LAN cable or the like having a coating thickness reduced to 0.45 mm or less to reduce the diameter. When applied as a material, the present inventors have obtained the knowledge that there is no adhesion between cables at the time of drawing out from a bobbin or a box, and the handleability such as wiring workability is excellent.

<(A) component>
Component (A) in the present embodiment: The ethylene-vinyl acetate copolymer has a vinyl acetate content of 14 to 29% by mass. When the vinyl acetate content is less than 14% by mass, the material becomes hard, so when applied as a cable sheath material, the cable becomes hard and curling remains. If it exceeds 29 mass%, the adhesiveness becomes high, and a phenomenon in which the cables adhere to each other occurs. The vinyl acetate content is preferably 17 to 28% by mass, and more preferably 25 to 28% by mass.

  The component (A) is not particularly limited in terms of molecular weight, melt viscosity, etc., and any ethylene-vinyl acetate copolymer can be used.

  Component (A): The ethylene-vinyl acetate copolymer is graft-copolymerized with a silane compound for silane crosslinking.

  The silane compound is required to have both a group capable of reacting with a polymer and an alkoxy group that forms a crosslink by silanol condensation. Specifically, vinyl silane compounds such as vinyltrimethoxysilane, vinyltriethoxylane, vinyltris (β-methoxyethoxy) silane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (amino Ethyl) aminosilane compounds such as γ-aminopropyltrimethoxysilane, β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, β- (3,4 epoxy cyclohexyl) ethyl Epoxy silane compounds such as trimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, acrylic silane compounds such as γ-methacryloxypropyltrimethoxysilane, bis (3- (triethoxy And polysulfide silane compounds such as ryl) propyl) disulfide and bis (3- (triethoxysilyl) propyl) tetrasulfide, and mercaptosilane compounds such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane. it can.

  A known general method for graft copolymerization of a silane compound, that is, a predetermined amount of a silane compound and a free radical generator are mixed with a base ethylene-vinyl acetate copolymer and melt-kneaded at a temperature of 80 to 200 ° C. The method can be used. As the free radical generator, organic peroxides such as dicumyl peroxide can be mainly used.

  The addition amount of the silane compound is not particularly limited, but 0.5 to 10.0 parts by mass is preferable with respect to 100 parts by mass of the ethylene-vinyl acetate copolymer in order to obtain good physical properties. If the amount is less than 0.5 parts by mass, a sufficient crosslinking effect cannot be obtained, and the strength and heat resistance of the composition are inferior. If it exceeds 10.0 parts by mass, the workability is remarkably reduced.

  Moreover, the optimal addition amount of the organic peroxide which is a free radical generator is 0.001-3.0 mass parts with respect to 100 mass parts of ethylene-vinyl acetate copolymers. When the amount is less than 0.001 part by mass, the silane compound is not sufficiently graft copolymerized and a sufficient crosslinking effect cannot be obtained. If it exceeds 3.0 parts by mass, scorching of the ethylene-vinyl acetate copolymer tends to occur.

  Moreover, in this invention, in order to bridge | crosslink the ethylene-vinyl acetate copolymer by which the silane compound was graft-copolymerized, a silanol condensation catalyst can be added. Such silanol condensation catalysts include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, stannous acetate, stannous caprylate, zinc caprylate, lead naphthenate, cobalt naphthenate, Acids such as carboxylic acid compounds and sulfonic acid compounds and alkalis such as amine compounds can be used.

  The addition amount of the silanol condensation catalyst is set to 0.001 to 0.5 parts by mass per 100 parts by mass of the ethylene-vinyl acetate copolymer depending on the type of the catalyst.

  As a method for adding the silanol condensation catalyst, there is a method of using a masterbatch previously mixed with an ethylene-vinyl acetate copolymer or a crystalline polyolefin resin in addition to the method of adding the silanol as it is.

<(B) component>
Component (B) in the present embodiment: Known crystalline polyolefin resins can be used, such as polypropylene, high density polyethylene, low density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene-butene- 1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, polybutene, poly-4-methyl-pentene-1, ethylene-butene-hexene terpolymer, ethylene-vinyl acetate Including at least one selected from a copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, and an ethylene-glycidyl methacrylate copolymer, alone or in combination It is desirable to blend the above. In view of the flexibility of the cable, the component (B) is preferably uncrosslinked.

  The polypropylene includes a block copolymer obtained by copolymerizing an α-olefin represented by ethylene, a random copolymer, and a polypropylene in which a rubber component represented by ethylene propylene rubber is introduced in the polymerization stage in addition to a homopolymer. Shall be.

  As said ethylene-vinyl acetate copolymer, what has crystallinity can be used, for example, a vinyl acetate content less than 29 mass% can be used.

  Moreover, it is also possible to use a crystalline polyolefin resin obtained by copolymerizing an unsaturated carboxylic acid or a derivative thereof as a part of the component (B). Thereby, (C) component: Reaction occurs between magnesium hydroxide and unsaturated carboxylic acid or its derivative, and the mechanical strength of the resin composition is improved by increasing the adhesion. As the crystalline polyolefin, those described above can be used as they are.

  Although it does not specifically limit as unsaturated carboxylic acid or its derivative (s), Maleic anhydride is suitable. Moreover, although the amount to replace is arbitrary, 0.5-10 mass parts is desirable. If the amount is less than 0.5 parts by mass, the effect of improving the strength cannot be obtained, and if it exceeds 10 parts by mass, the workability is remarkably lowered.

  In this Embodiment, the mixture ratio of the said (A) component is 40-80 mass parts among 100 mass parts of base polymers containing the said (A) component and the said (B) component. It is preferable that it is 50-70 mass parts. When the component (A) exceeds 80 parts by mass, the extrusion appearance is remarkably deteriorated. Moreover, when the amount of the component (A) is less than 40 parts by mass, good flexibility cannot be obtained.

  Moreover, in this Embodiment, it is preferable that the mixture ratio of the said (B) component is 60-20 mass parts among 100 mass parts of said base polymers, and it is more preferable that it is 50-30 mass parts. The phase of the component (A) is preferably dispersed in the phase of the component (B). As long as the effects of the present invention are exhibited, another polymer may be blended with the base polymer.

  As other polymers, polymers such as amorphous resins and uncrosslinked rubbers can be used. Examples of the amorphous resin include polystyrene, polycarbonate, polymethyl methacrylate, acrylonitrile-butadiene-styrene copolymer, polyphenylene ether, and the like. As uncrosslinked rubber, ethylene-propylene-diene copolymer, ethylene-propylene copolymer, ethylene-butene-1-diene copolymer, ethylene-octene-1-diene copolymer, acrylonitrile butadiene rubber, acrylic rubber Styrene-diene copolymers represented by styrene-butadiene rubber and styrene isoprene rubber, styrene-diene-styrene copolymers represented by styrene-butadiene-styrene rubber and styrene-isoprene-styrene rubber, and hydrogenated Styrenic rubber obtained by the above method.

<(C) component>
Component (C) in the present embodiment: The metal hydroxide imparts flame retardancy to the resin composition. Examples of such metal hydroxides include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, and the like. Among them, magnesium hydroxide having the highest flame retardant effect is preferable. These may be used alone or in combination of two or more. The metal hydroxide is desirably surface-treated from the viewpoint of dispersibility.

  As the surface treatment agent, a silane coupling agent, a titanate coupling agent, a fatty acid or a fatty acid metal salt, etc. can be used, and among them, a silane coupling agent in terms of enhancing the adhesion between the resin composition and the metal hydroxide. Is desirable.

  Examples of silane coupling agents that can be used include vinyl silane compounds such as vinyl trimethoxy silane, vinyl triethoxy lane, vinyl tris (β-methoxy ethoxy) silane, γ-aminopropyl trimethoxy silane, γ-aminopropyl triethoxy silane, N Aminosilane compounds such as β- (aminoethyl) γ-aminopropyltrimethoxysilane, β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, β- (3, 4-epoxycyclohexyl) epoxysilane compounds such as ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and acrylic silanization such as γ-methacryloxypropyltrimethoxysilane , Polysulfide silane compounds such as bis (3- (triethoxysilyl) propyl) disulfide, bis (3- (triethoxysilyl) propyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, etc. And mercaptosilane compounds.

  As a method for treating these surface treatment agents with a metal hydroxide, known methods such as a wet method, a dry method, and a direct kneading method can be used.

  Although the amount of treatment is not particularly limited, it is preferably in the range of 0.1 to 5% by mass with respect to the metal hydroxide. When the treatment amount is less than 0.1% by mass, the strength of the resin composition is lowered, and when it is more than 5% by mass, the workability is deteriorated.

  The average particle diameter of the metal hydroxide is more preferably 4 μm or less from the viewpoint of mechanical properties, dispersibility, and flame retardancy.

  The addition amount of the said (C) component is 30-150 mass parts with respect to 100 mass parts of said base polymers. More preferably, it is 50-100 mass parts. If the amount is less than 30 parts by mass, an excellent flame retardant effect cannot be obtained. If the amount exceeds 150 parts by mass, the flexibility and mechanical strength are significantly reduced.

<(D) component>
Component (D) in the present embodiment: The acrylic compound is a processing aid, specifically, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, isopropyl acrylate, n-propyl methacrylate, Isopropyl methacrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl What copolymerized 1 type, or 2 or more types of (meth) acrylic-acid alkylesters, such as a methacrylate and a tridecyl methacrylate, You can use. In addition to the above, (meth) acrylic acid and (meth) acrylic acid alkyl ester containing a hydroxy group can also be used.

  Examples of commercially available acrylic compounds as described above include, for example, METABRENE P-531A, METABRENE P-530A, METABRENE P-700, METABRENE P-1050, METABRENE L-1000 manufactured by Mitsubishi Rayon, and Kane Ace PA- manufactured by Kaneka Corporation. 20, Kane Ace PA-60, Kane Ace PA-100 and the like.

  The amount of component (D) added is 1 to 10 parts by mass with respect to 100 parts by mass of the base polymer. It is more preferable that it is 1-5 mass parts. If the amount is less than 1 part by mass, a smooth surface cannot be obtained in extrusion molding, and the dynamic friction coefficient becomes high.

<(E) component>
Component (E) in the present embodiment: The fatty acid amide compound is a lubricant. Specifically, stearic acid amide, palmitic acid amide, oleic acid amide, montanic acid amide, erucic acid amide, behenic acid amide, laurin Acid amide, ricinoleic acid amide, hydroxy stearic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl Palmitic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, ethylene bis lauric acid amide, ethylene bishydroxy stearic acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, hexamethylene bis olein Amides, m- xylylene bis stearic acid amide, p- phenylene-bis-stearic acid amide, N, N'-dioleyl adipic acid amide, N, N'-dioleyl sebacic acid amide.

  The amount of component (E) added is 0.01 to 2 parts by mass with respect to 100 parts by mass of the base polymer. It is more preferable that it is 0.05-1 mass part. If the amount is less than 0.01 parts by mass, the dynamic friction coefficient of the material becomes high. If the amount exceeds 2 parts by mass, the lubricant is deposited on the surface of the material, so that the appearance of the molded product is significantly impaired.

<Other additives>
In addition to the above, the non-halogen resin composition used in the embodiment of the present invention includes process oil, processing aid, flame retardant aid, crosslinking agent, crosslinking aid, antioxidant, lubricant, It is also possible to add additives such as compatibilizers, stabilizers, carbon black, and colorants.

[Method for producing non-halogen flame retardant resin composition]
Although there is no limitation as an apparatus which manufactures the non-halogen flame retardant resin composition which concerns on embodiment of this invention, General purpose things, such as a kneader, a Banbury mixer, a roll, a twin screw extruder, can be used. The production process includes (1) a step of graft copolymerizing a silane compound with an ethylene-vinyl acetate copolymer, (2) an ethylene-vinyl acetate copolymer, a crystalline polyolefin resin, a metal hydroxide, and an acrylic compound. , There are two processes of silane cross-linking the ethylene-vinyl acetate copolymer while kneading compounding agents such as fatty acid amide compound and silanol condensation catalyst, and a method of performing these separately, such as a twin screw extruder There is a technique for performing both steps by one extrusion, and there is no particular limitation.

  The order of kneading each component of the ethylene-vinyl acetate copolymer, crystalline polyolefin resin, metal hydroxide, acrylic compound, and fatty acid amide compound is arbitrary, and (1) ethylene-vinyl acetate. A method of kneading a copolymer, a metal hydroxide, an acrylic compound, and a fatty acid amide compound first, and adding a crystalline polyolefin resin later; (2) an ethylene-vinyl acetate copolymer and a crystalline polyolefin first. There are a method of kneading and adding a metal hydroxide, an acrylic compound, and a fatty acid amide compound later, and a method of (3) kneading all together. The silanol condensation catalyst is optimally added last. In addition, compounding agents such as antioxidants and colorants may be added at any timing.

[Sheath thickness]
The non-halogen flame retardant resin composition is applied as a sheath of a LAN cable. The thickness of the sheath is 0.2 to 0.45 mm. More preferably, it is 0.3 to 0.4 mm. If the thickness is less than 0.2 mm, sufficient flame retardancy as a cable cannot be obtained. If it is thicker than 0.45 mm, the outer diameter of the cable becomes thick, and the number of cables that can be laid decreases and the flexibility also decreases.

  As a sheath coating method, a known wire coating method using an extruder can be used.

  Examples of the present invention will be specifically described below.

[Production of cables of Examples and Comparative Examples]
The non-halogen flame retardant resin composition includes a step of graft copolymerizing a silane compound to an ethylene-vinyl acetate copolymer, and an ethylene-vinyl acetate copolymer obtained by graft copolymerization of the silane compound, a crystalline polyolefin resin, a metal It was produced by kneading compounding agents such as a hydroxide, an acrylic compound, a fatty acid amide compound, a silanol condensation catalyst, and the like, and crosslinking the ethylene-vinyl acetate copolymer with silane.

  In the step of graft copolymerizing the silane compound with the ethylene-vinyl acetate copolymer, the raw material ethylene-vinyl acetate copolymer (vinyl acetate content: 12, 14, 28, 33 mass%), vinyltrimethoxysilane, Prepare impregnated and mixed mill peroxide at a ratio of 100/3 / 0.02 parts by mass so that the residence time is about 5 minutes with a 40 mm extruder (L / D = 24) at 200 ° C. Extrusion and graft reaction were performed.

  In the next step, the components shown in the examples in Tables 1 and 2 were kneaded by batch feeding them into a 37 mm twin screw extruder (L / D = 60), and the silane compound was grafted during the kneading. A kneaded product was prepared by crosslinking the copolymerized ethylene-vinyl acetate copolymer. The temperature was 180 ° C., and the screw rotation speed was 150 rpm. This was pelletized to obtain a sheath material for cable production.

  The evaluation cable was produced by extruding a sheath in a tube shape using a 40 mm extruder (L / D = 24) preheated to 180 ° C. so as to have the thicknesses shown in Tables 1 and 2. As the cable core, two copper conductors having an outer diameter of 0.5 mm coated with polyethylene with a thickness of 0.2 mm were twisted, and four pairs were twisted. The extruded cable was wound around a bobbin having a body diameter of 500 mm. The total length of the cable was 3000 m.

[Evaluation of cables of Examples and Comparative Examples]
The cable produced by the above procedure was evaluated by the following method. The measurement results are shown in Tables 1 and 2.

  The mechanical strength and flame retardancy of the cable were evaluated according to JIS C 3005. The cable sheath had a tensile strength of 8 MPa or more and an elongation at break of 200% or more. For the flame retardancy evaluation, a 60-degree inclined combustion test was performed, the fire spread time after removing the flame was measured, and the fire extinguisher within 60 seconds was regarded as acceptable.

  As an evaluation method of the cable extrusion appearance, curl, and tackiness, the cable wound on the bobbin during extrusion was left for a week and then pulled out (surface smoothness, presence of bloom), The presence or absence and the presence or absence of adhesion were confirmed visually.

  The flexibility of the cable was evaluated based on the amount of deflection (distance reduced with respect to the horizontal) when one end of a cable having a length of 200 mm was fixed and a load of 50 g was applied to the other end. The greater the amount of deflection, the better the flexibility. The target value was the amount of cable deflection when a polyvinyl chloride sheath was used (the amount of deflection was 120 mm or more).

  In addition, the slipperiness (drawability) between cables using the same material was evaluated by dynamic friction coefficient measurement based on JIS K7125. As shown in FIG. 5, the test cable 11 is set between two fixed cables 12 that are fixed at the top and bottom, a load (19.6 N) is applied from above, and the test cable 11 is pulled out from the pulling force. The coefficient of dynamic friction was calculated, and a value equal to or less than 0.7 equivalent to a cable coated with polyvinyl chloride was accepted.

[Materials used] (Numbers correspond to the numbers in Tables 1 and 2)
1) Evaflex EV270 manufactured by Mitsui DuPont Polychemical (vinyl acetate content 28% by mass, molten finger (MI) 1 g / 10 min (unit omitted))
2) <Base> Made by Mitsui DuPont Polychemical, Evaflex P1205 (vinyl acetate content 12% by mass, MI 2.5), <Silane graft amount> 3%
3) <Base> Made by Mitsui DuPont Polychemical, Evaflex P1403 (vinyl acetate content 14% by mass, MI 1.3), <Silane graft amount> 3%
4) <Base> Made by Mitsui DuPont Polychemical, Everflex EV270 (vinyl acetate content 28% by mass, MI 1), <Silane graft amount> 3%
5) <Base> Made by Mitsui DuPont Polychemical, Everflex EV170 (vinyl acetate content 33% by mass, MI 1), <Silane graft amount> 3%
6) Nippon Polypro, Novatec BC6C (density 0.90 g / cm ³ , MI 2.5)
7) Made of prime polymer, Evolue SP2510 (density 0.923 g / cm ³ , MI 1.5)
8) Evaflex P1403 manufactured by Mitsui DuPont Polychemical (vinyl acetate content 14 mass%, MI 1.3)
9) Made of Nippon Polyethylene, Lexpearl A3100 (ethyl acrylate amount 10%, MI 3)
10) Made of prime polymer, Hi-Zex 5305E (density 0.951 g / cm ³ , MI 0.8)
11) Exelen VL200 (density 0.90 g / cm ³ , MI 2) manufactured by Sumitomo Chemical
12) manufactured by Kyowa Chemical Industry, Kisuma 5L (Silane treatment)
13) Made by Mitsubishi Rayon, Metabrene P-1050
14) Nippon Kasei, Sri-Packs O
15) Nitto Kasei, Neostan U-810
16) Ciba Japan, Irganox 1010

  As shown in Table 1, in Examples 1 to 12 according to the present invention, the mechanical strength, flame retardancy, and extrusion appearance are excellent, there is no curl, and low tackiness, flexibility, and low friction. Even better cables have been obtained.

  On the other hand, as shown in Table 2, in Comparative Example 1 in which the ratio of the component (A) is larger than that of the present invention, the extrusion appearance was uneven.

  In Comparative Example 2 in which the ratio of the component (A) is less than specified and in Comparative Example 3 in which the vinyl acetate content is less than specified (A), sufficient flexibility cannot be obtained, and curling remains on the cable. I have.

  In Comparative Example 4 using the component (A) having a vinyl acetate content higher than specified and Comparative Example 5 in which the component (A) is not silane-crosslinked, the adhesiveness at the time of withdrawal was rejected and the dynamic friction coefficient was also increased. . In Comparative Example 5, the tensile strength also decreased.

  In Comparative Example 6, since the thickness of the sheath was thinner than the specified value, the flame retardancy was rejected. In Comparative Example 7, the cable was harder and the curl remained.

  In Comparative Example 8 in which the amount of component (C) added was less than the specified value, the flame retardancy was low, and in Comparative Example 9 exceeding the specified amount, the flexibility and mechanical properties could not satisfy the target values. In addition, the mushroom remained.

  In Comparative Example 10 in which the amount of component (D) added was less than specified, the extrusion appearance was not smooth and the dynamic friction coefficient was high. In Comparative Example 11 where the amount of component (D) added was greater than the specified amount, flame retardancy was insufficient.

  In Comparative Example 12, in which the amount of the component (E) was less than specified, the slipping property of the material was inferior and the dynamic friction coefficient was high. In Comparative Example 13 in which the amount of the component (E) exceeds the specified amount, a phenomenon that the cable surface is whitened due to the bloom of the fatty acid amide compound is seen and the appearance is inferior.

  As described above, the present invention has excellent flexibility and low friction even when the sheath is thinned to reduce the diameter of the sheath, and there is no curl remaining between the cables. Since there is no adhesion, the wiring workability is greatly improved as compared with the conventional cable, and its industrial usefulness is extremely high.

1: Conductor, 2: Insulator, 3: Sheath, 4, 14: Intervening 5: Pressing tape, 6: Shield, 7: Ground wire 10, 20, 30, 40: Cable

Claims (3)

A LAN cable having a sheath covering the outer periphery of the cable core,
The cable core has a configuration in which a plurality of electric wires are twisted together,
The sheath is composed of 100 parts by mass of a base polymer containing (A) component: ethylene-vinyl acetate copolymer having a vinyl acetate content of 14 to 29% by mass and (B) component: crystalline polyolefin resin. The (A) component is 40 to 80 parts by mass, and (C) component: 30 to 150 parts by mass of the metal hydroxide and (D) component: acrylic compound 1 with respect to 100 parts by mass of the base polymer. 10 parts by mass, (E) component: 0.01 to 2 parts by mass of a fatty acid amide compound, and the component (A) comprises a non-halogen flame retardant resin composition that is silane-crosslinked,
LAN cable thickness of the sheath, 0.2～0.45Mm der is, twist lay of the cable core, characterized in that the structure stand out on the sheath surface. The LAN cable according to claim 1, wherein the dynamic friction coefficient between the same cables conforming to JIS K7125 is 0.7 or less. The LAN cable according to claim 1 or 2, wherein the component (B) is 60 to 20 parts by mass of 100 parts by mass of the base polymer .

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