JP2009263597A - Flame-retardant resin composition and flexible flat cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a halogen-free flame-retardant resin composition having high flame-retardancy which is excellent in flexibility, machine physical properties, heat aging resistance, heating deformation resistance, low temperature characteristics and electric insulation; and a flexible flat cable insulating-coated with the flame-retardant resin composition. <P>SOLUTION: Provided are a flame-retardant resin composition which is a flame-retardant resin composition wherein a polymer component contains a thermoplastic polyurethane elastomer having a JIS hardness of less than A98 and an ethylene copolymer, and a flame retardant component contains magnesium hydroxide, a 1,3,5-triazine derivative and a metal compound containing at least one type of metal atom selected from the group consisting of zinc, aluminum and tin and containing no halogen atom; and a flexible flat cable which is insulating-coated with the flame-retardant resin composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flame retardant resin composition and a flexible flat cable which is insulation-coated with the flame retardant resin composition. More specifically, the present invention exhibits a high degree of flame retardancy without containing a halogen flame retardant, flexibility, mechanical properties (tensile strength and tensile elongation at break), heat aging resistance, heat deformation resistance The present invention relates to a flame retardant resin composition excellent in heat resistance, low temperature characteristics (flexibility at low temperature) and electrical insulation, and a flexible flat cable insulated and coated with the flame retardant resin composition.

  In an insulated wire such as an insulated coated wire, an insulated coated shielded wire, and an insulated coated cable, the conductor and / or the jacket is insulated with an insulating material. Insulated wires are generally required to have flame retardancy and flexibility in addition to electrical insulation. Therefore, a polyolefin resin composition containing a soft polyvinyl chloride resin and a flame retardant is widely used as an insulating material for covering an insulated wire used for in-machine wiring of electronic equipment.

  For example, Japanese Patent Laid-Open No. 1-276514 (Patent Document 1) discloses a method of manufacturing a flexible flat cable in which a plurality of flat conductors arranged in parallel are integrally covered with a soft insulator. Patent Document 1 discloses a soft polyvinyl chloride resin as a soft insulator. Soft polyvinyl chloride resin has flame retardancy and flexibility, but because polyvinyl chloride resin is a polymer containing bound chlorine atoms, if the flexible flat cable is incinerated, it contains corrosive chlorine There is a strong risk of generating gas and dioxins. Since the soft polyvinyl chloride resin contains a large amount of additive components such as plasticizers and heavy metal stabilizers, when the flexible flat cable is discarded, these components are eluted and pollute the environment.

  The polyolefin resin composition used as an insulating material for an insulated wire generally contains a halogen-based flame retardant containing a bromine atom or a chlorine atom in the molecule. Halogen flame retardant has a high flame retardant effect. However, if an insulated wire covered with a polyolefin resin composition containing a halogen-based flame retardant is incinerated, corrosive gases and dioxins may be generated from the halogen compound contained in the insulating coating layer.

  In recent years, in order to meet the increasing demand for reducing the environmental burden, halogen-free insulated wires that have been insulation-coated using a resin material that does not contain a polyvinyl chloride resin or a halogen-based flame retardant have been developed. On the other hand, insulated wires used for in-machine wiring of electronic devices are generally required to have various characteristics that conform to UL (Underwriters Laboratories Inc.) standards.

  The UL standard stipulates in detail various characteristics such as flame retardancy, heat deformation resistance, low temperature characteristics, tensile properties after heat aging of coating materials, and the like to be satisfied by insulated wires. Among these, regarding flame retardancy, it is necessary to pass a vertical combustion test called a VW-1 test, which is one of the strictest requirements in the UL standard.

  As an insulating material for halogen-free insulated wires, a polyolefin resin composition in which a metal hydroxide represented by magnesium hydroxide (also referred to as “metal hydrate”) is blended with a polyolefin resin is widely used. Since the flame retardant effect of metal hydroxide is lower than that of halogen flame retardants, it is necessary to blend a large amount of metal hydroxide in the polyolefin resin in order to obtain an insulating material exhibiting a high degree of flame retardancy. is there. As a result, the mechanical properties (tensile strength and tensile elongation at break) and heat deformation resistance of the insulating coating layer are significantly reduced.

  When an insulating coating layer made of a polyolefin resin composition is irradiated with ionizing radiation such as an accelerated electron beam to crosslink, the mechanical properties and heat deformation resistance of the insulating coating layer can be improved. However, polyolefin resin compositions containing metal hydroxides are expensive compared to polyvinyl chloride resin, and require expensive irradiation devices and irradiation processes for irradiation with ionizing radiation. There is a disadvantage that it is bulky. There is a demand for development of a halogen-free insulated wire that satisfies the UL standard without irradiation cross-linking.

  Conventionally, JP 2004-10840 A (Patent Document 2) has proposed a resin composition for covering transmission lines in which a large amount of metal hydrate is blended with a resin component containing an ethylene copolymer and a polyester elastomer. . An example of Patent Document 2 shows an insulated wire in which a tin-plated annealed copper stranded wire (element diameter 0.18 mm, 21 strands) having a conductor diameter of 0.95 mmφ is coated with the resin composition for covering transmission lines. ing. However, the resin composition for covering transmission lines is not necessarily sufficient in flame retardancy and insulation resistance.

  In JP 2004-51903 A (Patent Document 3), a resin component containing an ethylene copolymer and a thermoplastic resin having a polyester type or polyether type segment is treated with an organic peroxide and a silane coupling agent. A flame retardant resin composition obtained by melting and kneading the metal hydrate, and an insulated wire, an insulated cable or an optical fiber cord coated with the flame retardant resin composition have been proposed. An example of Patent Document 3 shows an insulated wire in which a tin-plated annealed copper stranded wire having a conductor diameter of 0.95 mmφ (element wire diameter: 0.18 mm, 21 strands) is coated and molded with the flame retardant resin composition. Yes. The Example of patent document 3 shows that this insulated wire passed the horizontal combustion test of UL specification.

  However, even if a conventional flame retardant resin composition is used, it is difficult to form an insulating coating layer with a high balance of flame retardancy, mechanical properties, heat resistance, heat aging resistance, heat deformation resistance, etc. In particular, it has been extremely difficult to obtain an insulated wire exhibiting a high degree of flame retardancy that passes the UL standard vertical combustion test VW-1.

  International Publication No. 2007/058349 (Patent Document 4) includes a thermoplastic polyurethane elastomer (A) having a JIS hardness of A98 or less measured in accordance with JIS K 7311 of Japanese Industrial Standard, and a vinyl acetate unit content of 50 to 50. 40 wt% of metal hydroxide with respect to 100 wt% of resin component containing 90 wt% of ethylene-vinyl acetate copolymer (B) in a weight ratio (A: B) of 40:60 to 90:10. A flame retardant resin composition containing ˜250 parts by weight and an insulated wire formed by coating the flame retardant resin composition on a conductor have been proposed.

  The flame retardant resin composition described in Patent Document 4 exhibits a high degree of flame retardancy, and is an insulating coating layer excellent in mechanical properties, heat resistance, heat aging resistance, heat deformation resistance, low temperature characteristics, and electrical insulation properties Can be formed. In an example of Patent Document 4, an insulated wire formed by insulating coating a conductor (outer diameter 0.48 mm) in which seven strands of an annealed copper wire having a strand diameter of 0.16 mm are twisted with the flame-retardant resin composition, It has been shown that the UL vertical combustion test VW-1 has been passed.

  The flame retardant resin composition described in Patent Document 4 exhibits excellent physical properties and various characteristics even when used as an insulating material for flexible flat cables. A flexible flat cable is a kind of insulated wire formed by insulatingly molding a plurality of flat conductors arranged in parallel with an insulating material.

  However, as a result of studies by the present inventors, a flexible flat cable formed by insulatingly molding a plurality of flat conductors arranged in parallel with the flame-retardant resin composition described in Patent Document 4, It has been found that when the number of flat rectangular conductors is greatly increased, the flame retardancy tends to decrease and the vertical combustion test VW-1 of the UL standard tends to be rejected. This tendency becomes stronger as the width and / or thickness of each rectangular conductor becomes smaller.

  The flexible flat cable has a flat belt shape and becomes wider as the number of flat conductors increases, and the amount of the flame-retardant resin composition existing around and between the flat conductors also increases. . Therefore, it is estimated that the combustion behavior of the flexible flat cable is different from that of a single-core or multi-core insulated wire having a substantially circular cross section. The flexible flat cable is suitable for use in a movable part or a narrow part of an electronic device, and there is a strong demand for high performance by making it flame retardant.

  Since the flame retardant resin composition described in Patent Document 4 requires the use of an ethylene-vinyl acetate copolymer having a high vinyl acetate unit content, the tolerance for selecting the physical properties and characteristics of the insulating coating layer is small. There is also a problem.

Japanese Patent Laid-Open No. 1-276514 Japanese Patent Laid-Open No. 2004-10840 JP 2004-51903 A International Publication No. 2007/058349 Pamphlet

  The object of the present invention is to display a high degree of flame retardancy without containing a halogen flame retardant, flexibility, mechanical properties (tensile strength and tensile elongation at break), heat aging resistance, heat deformation resistance, An object of the present invention is to provide a flame retardant resin composition excellent in low temperature characteristics (flexibility at low temperature) and electrical insulation.

  Another object of the present invention is a flexible flat cable insulation-coated with a flame retardant resin composition exhibiting such excellent physical properties and characteristics, and even if the number of flat conductors increases, the vertical of UL standard The object is to provide a flexible flat cable exhibiting a high degree of flame retardancy that passes the combustion test VW-1.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that in a flame-retardant resin composition containing a polymer component and a flame retardant component, the polymer component has a JIS hardness measured according to JIS K 7311 of A98. Less than a thermoplastic polyurethane elastomer and an ethylene copolymer in a specific weight ratio, and the flame retardant component includes magnesium hydroxide, 1,3,5-triazine derivative, and zinc, aluminum, and tin. The inventors have conceived a flame retardant resin composition containing at least one metal atom selected from the group consisting of three kinds of metal compounds not containing a halogen atom in a specific ratio.

  The flexible flat cable formed by insulation coating with the flame-retardant resin composition of the present invention can be applied to the UL standard vertical cable even when the number of rectangular conductors to be insulation-coated at once is increased to 20 or more, and further to 60 or more. It shows a high degree of flame retardancy that passes the combustion test VW-1. Such a high degree of flame retardancy can be achieved even if the width and thickness of each flat conductor are reduced.

  The flame retardant resin composition of the present invention exhibits flexibility and is excellent in tensile properties such as tensile strength and tensile breaking elongation. The flame retardant resin composition of the present invention is excellent in various properties such as heat aging resistance, low temperature characteristics, and heat deformation resistance. The flame retardant resin composition of the present invention is not limited to the ethylene-vinyl acetate copolymer having a high vinyl acetate unit content, so the ethylene copolymer type and copolymerization ratio should be selected. Thus, it is possible to improve various characteristics such as moisture absorption resistance of the insulating coating layer and prevention of adhesion between the insulating coating layers.

  The flame-retardant resin composition of the present invention can also be used as an insulating coating layer and / or jacket for various insulated wires other than flexible flat cables. The flame-retardant resin composition of the present invention can be extruded into a tube shape to form an insulating tube. The present invention has been completed based on these findings.

According to the present invention, in a flame retardant resin composition containing a polymer component and a flame retardant component,
(1) The polymer component is a weight ratio (A: B) of a thermoplastic polyurethane elastomer (A) having a JIS hardness of less than A98 measured according to JIS K 7311 of Japanese Industrial Standard and an ethylene copolymer (B). In a ratio within the range of 25:75 to 95: 5, and
(2) The flame retardant component is each 100 parts by weight of the polymer component,
40 to 250 parts by weight of magnesium hydroxide (C),
1 to 30 parts by weight of 1,3,5-triazine derivative (D), and a metal compound (E) containing at least one metal atom selected from the group consisting of zinc, aluminum, and tin, and not containing a halogen atom Is contained in an amount of 1 to 30 parts by weight, and a flame retardant resin composition is provided.

  According to the present invention, in the flexible flat cable in which a plurality of flat conductors arranged in parallel are collectively covered with an insulating material, the insulating material is the flame-retardant resin composition. A flexible flat cable is provided.

  The flame-retardant resin composition of the present invention exhibits a high degree of flame retardancy despite being halogen-free containing no halogen atom or halogen compound. The flame-retardant resin composition of the present invention is excellent in mechanical properties without being subjected to irradiation crosslinking by ionizing radiation, and is excellent in flexibility, heat aging resistance, heat deformation resistance, low temperature characteristics, and electrical insulation. An insulating coating layer can be formed.

  Since the flame-retardant resin composition of the present invention has flame retardancy and flexibility, it is suitable as an insulating coating layer for flexible flat cables. The flexible flat cable having an insulating coating layer made of the flame retardant resin composition of the present invention has a high degree of flame resistance that passes the UL standard vertical flame test VW-1 even if the number of flat conductors is greatly increased. Indicates.

  A thermoplastic elastomer (TPE) is a polymer having both a rubber component (soft segment) having elasticity in a molecule and a molecular constraint component (hard segment) for preventing plastic deformation.

  The thermoplastic polyurethane elastomer (TPU) used in the present invention is produced by a three-component intermolecular reaction of a high molecular weight diol (long chain diol), a diisocyanate, and a low molecular weight diol (short chain diol). It is a polymer having (—NH—COO—). Long chain diols and short chain diols undergo an addition reaction with diisocyanate to produce linear polyurethanes.

  The long-chain diol forms a flexible part (soft segment) of the elastomer, and the diisocyanate and the short-chain diol form a hard part (hard segment) of the elastomer. The basic properties of thermoplastic polyurethane elastomers are mainly determined by the type of long-chain diol, but the hardness is adjusted by the proportion of hard segments.

  Examples of the long-chain diol include polypropylene glycol (PPG), polytetramethylene glycol (PTMG), poly (butylene adipate) diol (PBA), poly-ε-caprolactone diol (PCL), poly (hexamethylene carbonate) diol ( PHC), poly (ethylene / 1,4-agitate) diol, poly (1,6-hexylene / neopentylene adipate) diol, and the like. The types of thermoplastic polyurethane elastomers are classified into, for example, caprolactone type, adipate type (also referred to as “ester type”), PTMG type (also referred to as “ether type”), polycarbonate (PC) type, etc., depending on the type of long chain diol. It is done.

  Examples of the diisocyanate include 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and the like. Examples of the short-chain diol include 1,4-butanediol, 1,6-hexanediol, 1,4-bis (2-hydroxyethoxy) benzene, and the like.

  The thermoplastic polyurethane elastomer used in the present invention has a hardness (unit = JIS; “JIS”) measured using a type A durometer in accordance with JIS K 7311 (Testing method for polyurethane-based thermoplastic elastomer) defined in Japanese Industrial Standards. (Also referred to as “A hardness”) is less than A98. If the thermoplastic polyurethane elastomer has a JIS hardness of A98 or higher, the tensile elongation at break of the flame retardant resin composition becomes too low, and the flexibility is impaired when the insulating coating layer is formed.

  The JIS hardness of the thermoplastic polyurethane elastomer used in the present invention is preferably in the range of A50 to A97, more preferably A60 to A95, and particularly preferably A70 to A93. By having the JIS hardness of the thermoplastic polyurethane elastomer within the above range, the properties of the flame-retardant resin composition such as flexibility, mechanical properties, heat aging resistance, heat deformation resistance, and low-temperature properties should be highly balanced. Is preferable.

  The melt flow rate (abbreviated as “MFR”; measured in accordance with JIS K 7210 at a temperature of 210 ° C. and a load of 5,000 g) is used as an index of the molecular weight of the thermoplastic polyurethane elastomer used in the present invention. In view of the above, it is preferably 0.1 to 100 g / 10 minutes, and more preferably 0.5 to 50 g / 10 minutes.

  The ethylene copolymer used in the present invention is a copolymer of ethylene and a comonomer copolymerizable with the ethylene. As the comonomer, monovinyl monomers such as vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, acrylic acid, and methacrylic acid are representative.

  Specific examples of the ethylene copolymer used in the present invention include ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl methacrylate copolymer (EMMA), Ethylene-acrylic acid copolymer (EAA), ethylene-methyl acrylate copolymer (EMA), ethylene-methacrylic acid copolymer (EMAA), ethylene-acrylic acid copolymer (EAA), partially metallized Ethylene ionomers may be mentioned. The ethylene copolymer may be a terpolymer obtained by copolymerizing a comonomer having a functional group such as maleic anhydride or a glycidyl group-containing monomer in addition to the comonomer as described above.

  Among the ethylene copolymers, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), and ethylene-methyl methacrylate copolymer (EMMA) are preferable.

  Content of the repeating unit derived from the comonomer in an ethylene copolymer is 5 to 90 weight% normally, Preferably it is 10 to 80 weight%. If the content of the repeating unit derived from the comonomer is too small, compatibility with the thermoplastic polyurethane elastomer is deteriorated, flame retardancy is lowered, or mechanical properties such as tensile strength are lowered. When there is too much content of the repeating unit derived from a comonomer, mechanical properties will fall.

  Since the flame retardant resin composition of the present invention contains a specific three-component flame retardant, various ethylene copolymers such as EEA and EMMA other than EVA can be widely used as the ethylene copolymer. EVA can be used from a low content to a high content of vinyl acetate units.

  In the insulating coating layer made of the flame retardant resin composition of the present invention, the decrease in tensile strength due to moisture absorption is suppressed. Therefore, an insulated wire having an insulating coating layer made of the flame retardant resin composition of the present invention can maintain high mechanical properties of the insulating coating layer even when exposed to a high temperature and high humidity environment for a long time. it can. When EVA is used as the ethylene copolymer, EVA having a vinyl acetate unit content of 10 wt% or more and less than 50 wt% is used from the viewpoint of maintaining a high tensile strength after moisture absorption of the insulating coating layer. It is preferable. The tensile strength after moisture absorption of the insulating coating layer can be maintained at a high level also by using various ethylene copolymers such as EEA and EMMA other than EVA.

  Insulated wires may stick to each other when the insulation coating layer has high adhesiveness. When the insulated insulated wire is peeled off, traces such as white lines may remain on the insulating coating layer. From the standpoint of preventing such an insulated wire from sticking, when EVA is used as the ethylene copolymer, it is preferable to use EVA having a vinyl acetate unit content of 10 wt% or more and less than 50 wt%. The use of various ethylene copolymers such as EEA and EMMA other than EVA can also prevent the insulated wires from sticking to each other.

  The use of EVA with a low content of vinyl acetate units can alleviate the odor of acetic acid. In addition to the above, desired physical properties and characteristics can be imparted to the insulating coating layer made of the flame retardant resin composition by selecting the comonomer type and copolymerization ratio.

  MFR (measured at a temperature of 190 ° C. and a load of 2160 g according to JIS K 7210) as an index of the molecular weight of the ethylene copolymer is preferably from 0.1 to 100 g / 10 min from the viewpoint of extrusion processability and mechanical properties, More preferably, it is 0.5-50 g / 10min.

  The content ratio of the thermoplastic polyurethane elastomer (A) and the ethylene copolymer (B) is in the range of 25:75 to 95: 5, preferably 30:70 to 10:90 by weight ratio (A: B). is there. When the content ratio of the thermoplastic polyurethane elastomer is too low, strength properties, heat aging resistance, heat deformation resistance, and the like of the insulating coating layer made of the flame retardant resin composition are lowered. When the content ratio of the thermoplastic polyurethane elastomer is too high, it becomes difficult to highly fill a flame retardant component such as a metal hydroxide. By containing these polymer components in a weight ratio within the above range, the physical properties and characteristics of the insulating coating layer made of the flame retardant resin composition can be highly balanced.

  The flame retardant resin composition of the present invention may contain a polymer compatibilizer as a polymer component in addition to the thermoplastic polyurethane elastomer and the ethylene copolymer. Examples of the polymer compatibilizer include acid-modified high-density polyethylene, acid-modified low-density polyethylene, acid-modified linear low-density polyethylene, acid-modified polypropylene, acid-modified styrene elastomer, and acid-modified ethylene-vinyl acetate copolymer. And acid-modified polymers such as acid-modified ethylene-unsaturated carboxylic acid derivative copolymers. The acid-modified polymer is a method in which each polymer or copolymer is modified with 0.1 to 10% by weight of an acid anhydride such as maleic anhydride and / or an unsaturated carboxylic acid such as acrylic acid or methacrylic acid. Can be obtained by:

  Polymer compatibilizers include acid-modified polymers, ethylene-glycidyl methacrylate copolymers, ethylene-vinyl acetate-glycidyl methacrylate terpolymers, ethylene-methyl acrylate-glycidyl methacrylate terpolymers, etc. It is possible to use an ethylene-α-olefin copolymer having a number of epoxy groups.

  Polymer compatibilizers include acid-modified polymers, ethylene-α-olefin copolymers, ethylene-ethyl acrylate-maleic anhydride, ethylene-methyl acrylate-maleic anhydride, ethylene-acrylic acid-anhydride It is also possible to use an ethylene-α-olefin copolymer with maleic anhydride in a copolymerized form rather than a modification such as maleic acid.

  By blending the polymer compatibilizer, the mechanical properties (tensile strength and elongation at break) of the insulating coating layer made of the flame retardant resin composition can be improved. The reason is presumed to be that when a polymer compatibilizer is used, the compatibility between the polymer component and the flame retardant component is improved. When using a polymer compatibilizer, the content thereof is usually 1 to 20% by weight, preferably 3 to 15% by weight in the polymer component. When the content of the polymer compatibilizer is too large, the compatibility with the thermoplastic polyurethane elastomer is lowered, and the mechanical properties of the insulating coating layer tend to be lowered.

In the present invention, as a flame retardant component,
1) Magnesium hydroxide (C),
2) 1,3,5-triazine derivative (D), and 3) metal compound (E) containing at least one metal atom selected from the group consisting of zinc, aluminum, and tin, and not containing a halogen atom
These three types of compounds are selectively used in combination.

  Magnesium hydroxide (C) is a typical metal hydroxide having excellent flame retardancy. As magnesium hydroxide, it is preferable to use a synthetic product (synthetic magnesium hydroxide). Magnesium hydroxide is not only a synthetic product, but also naturally produced magnesium hydroxide made from brucite ore (natural magnesium hydroxide), flame retardancy, tensile properties, heat deformation resistance, low temperature characteristics, etc. Since a flame retardant resin composition satisfying the specifications of the UL standard can be obtained, it is advantageous in reducing the production cost.

The average particle diameter (median diameter by laser diffraction / scattering method) of magnesium hydroxide is preferably from 0.3 to 7 μm, more preferably from 0.5 to 5 μm, and particularly preferably from the viewpoint of dispersibility with respect to the polymer component. 6 to 3 μm. The BET specific surface area of magnesium hydroxide is preferably ^{2 to 20} m ² / g, more preferably 3 to 15 m ² / g.

  Magnesium hydroxide can be of a grade not subjected to surface treatment, but from the viewpoint of dispersibility with respect to polymer components, fatty acids such as stearic acid and oleic acid, phosphate esters, silane coupling agents, It is preferable to use a grade whose surface is treated with a surface treatment agent such as a titanium coupling agent or an aluminum coupling agent.

  As the surface treatment agent, a silane coupling agent is preferable. Examples of the silane coupling agent include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, methacrylosiloxane. Examples thereof include, but are not limited to, propyltrimethoxysilane and mercaptopropyltrimethoxysilane.

  The content of magnesium hydroxide is 40 to 250 parts by weight, preferably 50 to 240 parts by weight, and more preferably 60 to 220 parts by weight with respect to 100 parts by weight of the polymer component. If the magnesium hydroxide content is too low, a high degree of flame retardancy cannot be achieved. When there is too much content of magnesium hydroxide, a mechanical physical property and a low temperature characteristic show a tendency to fall.

  Examples of the 1,3,5-triazine derivative (D) include, but are not limited to, melamine, cyanuric acid, isocyanuric acid, melamine cyanurate, and melamine sulfate. Among these 1,3,5-triazine derivatives, melamine cyanurate is preferable because of excellent flame retardancy.

  The 1,3,5-triazine derivative can be used as an untreated product, but from the viewpoint of dispersibility, the one treated with a surface treatment agent such as fatty acid or silane coupling agent as described above should be used. You can also. The average particle diameter (median diameter by laser diffraction / scattering method) of the 1,3,5-triazine derivative is preferably 0.1 to 20 μm, more preferably 0.3 to 10 μm, from the viewpoint of dispersibility in the polymer component. It is.

  The content of the 1,3,5-triazine derivative is 1 to 30 parts by weight, preferably 3 to 28 parts by weight, more preferably 5 to 25 parts by weight with respect to 100 parts by weight of the polymer component. If the content of the 1,3,5-triazine derivative is too small, a high degree of flame retardancy cannot be achieved. When the content of the 1,3,5-triazine derivative is too large, mechanical properties and low temperature characteristics are deteriorated.

Examples of the metal compound (E) containing at least one metal atom selected from the group consisting of zinc, aluminum, and tin and not containing a halogen atom include zinc oxide (zinc white), zinc borate, zinc carbonate, and the like. Zinc compounds; compounds containing zinc and tin such as zinc stannate (ZnSnO ₃ ) and zinc hydroxystannate [ZnSn (OH) ₆ ]; aluminum compounds such as aluminum hydroxide, alumina and boehmite;

  From the viewpoint of dispersibility, the metal compound (E) may be used after surface treatment with a surface treatment agent such as a fatty acid or a silane coupling agent. The average particle diameter (median diameter by laser diffraction / scattering method) of the metal compound (E) is preferably 0.1 to 20 μm, more preferably 0.3 to 5 μm, from the viewpoint of dispersibility with respect to the polymer component.

  Content of a metal compound (E) is 1-30 weight part with respect to 100 weight part of polymer components, Preferably it is 3-28 weight part, More preferably, it is 5-25 weight part. If the content of the metal compound is too small, a high degree of flame retardancy cannot be achieved. When there is too much content of this metal compound, a mechanical physical property and a low-temperature characteristic will fall.

  As a flame retardant component, it is difficult to selectively combine three types of compounds consisting of magnesium hydroxide (C), 1,3,5-triazine derivative (D), and metal compound (E). The flame retardancy of the flammable resin composition can be greatly increased. Therefore, the flame retardant resin composition of the present invention does not require the use of EVA having a high vinyl acetate unit content, unlike the flame retardant resin composition disclosed in Patent Document 4, Various ethylene copolymers can be widely used. As for EVA, EVA having a low content of vinyl acetate units can also be used.

  By using a flame retardant component composed of a combination of these three components, the flexible flat cable formed by insulation coating using the flame retardant resin composition of the present invention greatly increases the number of flat conductors (number of cores). Even if it is increased, it is possible to show a high level of flame retardancy sufficient to pass the UL standard vertical combustion test VW-1.

  The total content of the flame retardant component consisting of magnesium hydroxide (C), 1,3,5-triazine derivative (D), and metal compound (E) is based on 100 parts by weight of the polymer component from the viewpoint of flame retardancy. The amount is preferably 75 to 310 parts by weight, more preferably 85 to 280 parts by weight, and particularly preferably 110 to 250 parts by weight. When there is too little total content of a flame retardant component, it will become difficult to obtain sufficient flame retardance. When there is too much content of a flame retardant component, extrusion moldability, flexibility, a softness | flexibility, tensile fracture | rupture elongation, etc. show a tendency to fall. Here, 100 parts by weight of the polymer component is calculated based on the total amount of the thermoplastic polyurethane elastomer, the ethylene copolymer, and the polymer compatibilizer (when added).

  The flame retardant resin composition of the present invention preferably contains an antioxidant in order to prevent oxidative deterioration during melt molding or use. Antioxidants include pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxy Phenyl) -propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, triethylene glycol-bis- [3- (3- phenolic antioxidants such as t-butyl-4-hydroxy-5-methylphenyl) propionate]; amine antioxidants such as 4,4'-dioctyl diphenylamine and N, N'-diphenyl-p-phenylenediamine Bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide, 2- Le mercaptobenzimidazole, pentaerythritol - tetrakis - sulfur-based antioxidant such as (3-laurylthiopropionate); and the like.

  Of these antioxidants, phenolic antioxidants are preferred. The antioxidant is preferably used in a proportion of 0.1 to 3 parts by weight, more preferably 0.3 to 2 parts by weight with respect to 100 parts by weight of the polymer component.

  The flame retardant resin composition of the present invention preferably contains a lubricant from the viewpoints of extrudability, prevention of adhesion between insulated wires, and the like. Examples of the lubricant include hydrocarbon lubricants, fatty acid lubricants, higher alcohol lubricants, fatty acid amide lubricants, metal soap lubricants, ester lubricants, and the like. Among these, fatty acid amide type lubricants are preferable.

  Examples of the fatty acid amide lubricant include stearic acid amide, oleic acid amide, erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide and the like. Among these fatty acid amide-based lubricants, stearic acid amide is preferred because it is highly effective in preventing sticking due to the insulating coating layer of the insulated wire. The lubricant is preferably used in a proportion of 0.1 to 3 parts by weight, more preferably 0.3 to 2 parts by weight with respect to 100 parts by weight of the polymer component.

  The flame retardant resin composition of the present invention includes, as desired, a processing stabilizer, a hydrolysis inhibitor, a heavy metal deactivator, a colorant, a filler, a reinforcing material, a foaming agent, other non-halogen flame retardants or Various additives such as a flame retardant aid can be contained.

  The flame-retardant resin composition of the present invention can be prepared by a method in which each component is mixed using a melt mixer such as an open roll, a Banbury mixer, a pressure kneader, a single-screw or multi-screw mixer. . The flame retardant resin composition is preferably formed in the form of pellets from the viewpoints of melt processability, handleability, and meterability.

  The flame-retardant resin composition of the present invention can be used for forming an insulating coating layer of an insulated wire. The insulated wire has a structure in which an insulating coating layer is formed on a conductor. The conductor may have any shape such as a single core made of one conductor, a plurality of cores made of a plurality of conductors, and a stranded wire formed by twisting a plurality of strands. The shape of the insulated wire is not limited to a specific one. The flame retardant resin composition of the present invention can form an insulating coating layer by a method of extruding and coating on a conductor using a melt extruder.

  The shielded electric wire is a shielded electric wire, and a coaxial cable is a typical one. When the shielded electric wire is a single core, the outer side of the core wire conductor is covered with an insulating coating, the outer side is covered with an offset wire serving as a shield, and an insulating coating layer is further covered as an outer jacket. The flame-retardant resin composition of the present invention can form an insulating coating layer of a conductor and can also form an insulating coating layer of a jacket. In the case of multi-core shielded wires, multiple cables are covered together and covered with an offset wire, and an insulation coating layer is applied as an outer covering, or each single core is covered with an offset wire and shielded. Some bundles are covered with insulation. These jackets can be formed as insulating coating layers formed from the flame-retardant resin composition of the present invention.

  If an insulation coating layer formed from the flame-retardant resin composition of the present invention is disposed as a jacket of a single-core or multi-core insulated wire, an insulated cable can be obtained. Insulated cables having a plurality of cores include flat cables.

  The flame-retardant resin composition of the present invention can produce an insulating tube by melt extrusion into a tube shape. When the insulating tube is expanded in the radial direction under heating conditions and its shape is cooled and fixed, a shrinkable tube is obtained. The insulating tube can be applied to applications that require electrical insulation. A shrinkable tube can be used for insulation protection, such as an edge part of an insulated wire, and a junction, for example.

  Among flat cables, a flat cable obtained by collectively forming a plurality of flat conductors arranged in parallel with an insulating coating material is a belt-like cable called a flexible flat cable (FFC). Suitable for use in moving parts and narrow places.

  The flame-retardant resin composition of the present invention can be used as an insulating coating material for flexible flat cables. The insulation coating layer formed using the flame retardant resin composition of the present invention may be subjected to irradiation cross-linking treatment, but is excellent in various properties such as mechanical properties and flame retardant properties even without performing irradiation cross-linking treatment. ing.

  When the flame-retardant resin composition of the present invention is used as an insulating coating layer of a flexible flat cable, even if the number of flat conductors is greatly increased, the flame retardant resin can pass UL standard vertical flame test VW-1 The flexible flat cable which shows can be obtained.

  The flat conductor used in the flexible flat cable of the present invention is not particularly limited as long as it is a flat wire conductor, but a flat tin-plated copper wire is typical.

  The flat conductor used in the present invention has a width W of usually 0.1 to 1.6 mm and a thickness T of usually 0.03 to 0.15 mm. The shape of the flat conductor has a width W larger than its thickness T (ie, W> T), and the ratio W / T of the width W to the thickness T is usually 5 to 45, and in many cases 6 to 16 It is.

  Specific examples of the conductor size (W × T; unit mm) include, for example, 0.5 × 0.05 (W / T = 10), 0.6 × 0.1 (W / T = 6), 0. 7 × 0.032 (W / T = 22), 0.7 × 0.1 (W / T = 7), 0.7 × 0.05 (W / T = 12), 0.7 × 0.035 (W / T = 20), 0.8 × 0.1 (W / T = 10), 0.8 × 0.05 (W / T = 13), 1.2 × 0.15 (W / T = 8), 1.4 × 0.032 (W / T = 44), and the like, but are not limited thereto.

The cross-sectional area of the flat conductor is preferably AWG # 20 to AWG # 35 (that is, 0.15 mm ² to 0.52 mm ² ).

  It is preferable that a plurality of rectangular conductors used in one flexible flat cable have the same cross-sectional shape including the width and thickness, but if necessary, a plurality of rectangular conductors having different cross-sectional shapes are used in combination. can do. The conductor pitch is also preferably equal, but if necessary, some of the rectangular conductors may be arranged at a partly different conductor pitch. For example, by changing the cross-sectional shape and / or the conductor pitch of some of the flat conductors of the flexible flat cable from those of others, portions having different allowable current values and conductor resistances may be provided. When splitting or branching a flexible flat cable by splitting it at any intermediate width, if the flat conductor has a different cross-sectional shape and / or conductor pitch, the split or branched flexible flat cable can be used according to the respective application. It is also possible to do.

  As shown in FIG. 1, the flexible flat cable of the present invention is formed by arranging a plurality of flat conductors 11 in parallel and integrally insulatingly forming the periphery of each flat conductor and between each flat conductor with an insulating coating material. A strip-shaped cable 10 provided with an insulating coating layer 12. Although FIG. 1 shows the case where the number of flat conductors is four, in general, the number of flat conductors in one flexible flat cable depends on the overall width, the shape of the flat conductor, the size of the conductor pitch, and the like. Although it is different, it is usually 7 to 100 in an arrangement with a small pitch, and is usually 4 to 60 in an arrangement with a large pitch, but is not limited thereto. The interval between the center portions of the width of the flat conductor is called a conductor pitch. The conductor pitch can be appropriately set as desired, but in many cases is about 0.5 mm to 2.54 mm.

  The cross-sectional shape of the flexible flat cable 10 shown in FIG. 1 is substantially rectangular (elongated rectangle). The flexible flat cable has a symmetrical shape with respect to the center point PO, and is provided with cuts 13 on both surfaces of the insulating coating layer 12 along the longitudinal direction at an intermediate position between two adjacent flat conductors 11 and 11. preferable. At the same time, it is preferable to provide corner cuts 15 at a total of four corners of the two margin portions 14.

  The shape of the cut 13 is typically a V shape, an arc shape, a U shape, or the like. In this case, it is preferable to arrange the rectangular conductors having the same width or the same width and thickness at equal intervals (same conductor pitch). The width of the margin portion is preferably ½ of the interval between the rectangular conductors. The margin portion means between the end portion of the flexible flat cable in the longitudinal direction and the end portion of the flat conductor adjacent thereto.

  Using this cut 13, the flexible flat cable can be split or branched at an arbitrary width. It is preferable that the corner notches 15 at the four corners of the margin portion 14 have a shape that appears when the flexible flat cable is divided or branched by the notches 13 provided in the insulating coating layer 12. For example, when the cut 13 provided in the insulating coating layer 12 is V-shaped, if the flexible flat cable is cut and divided or branched by the V-shaped cut 13, a substantially diagonal straight corner cut shape appears. It will be. In this case, it is preferable that the shape of the corner cuts 15 at the four corners of the margin portion 14 is also the same diagonal straight line in advance. When the cut 13 provided in the insulating coating layer 12 has an arc shape, if the arc-shaped cut 13 is torn and divided or branched, a corner cut shape having a cross-sectional shape that is ½ of a semicircle appears. become. In this case, it is preferable that the shape of the corner notches 15 at the four corners of the margin portion 14 also be a half of the same semicircle in advance. It is preferable to deal with the case where the cut 13 has another shape in the same manner as described above.

  A flexible flat cable insulated with a flame retardant resin composition is coated with a plurality of rectangular conductors fed to a die of an extruder at a predetermined tension and pitch, and the flame retardant resin composition is melt extruded from the die. Can be manufactured. A flexible flat cable often has a different number of flat conductors depending on a portion to which the flexible flat cable is applied. Replacing the die according to the number of flat conductors is expensive and laborious. If the flat cable which has many flat rectangular conductors is produced and it can divide | segment into the flexible flat cable which has a desired number of flat conductors corresponding to each specification, the said problem can be eased. The same applies to the case where the flexible flat cable needs to be branched on the way.

  In the conventional flexible flat cable, the width of the margin provided at both left and right ends is longer than half the width of the gap between the flat conductors. When divided into a plurality of flexible flat cables having conductors, the margin widths of the divided flexible flat cables are different. For this reason, when the connector is attached to the end portion, the position of the flat conductor is shifted, so that position adjustment must be performed or attachment may be impossible.

  On the other hand, the above problem can be solved by adjusting the width of the margin 14, the shape of the notch 13, and the shape of the notch 15. That is, the divided or branched flexible flat cable always has a certain margin. For this reason, since the position of the flat conductor is constant, the connector can be easily attached without adjusting the position. A flexible flat cable having a plurality of types of flat conductors of a desired number after division or branching can be manufactured by one extrusion process using the same die.

  As shown in a perspective view of FIG. 2, the preferred flexible flat cable of the present invention is a flexible flat cable 10 in which a plurality of flat conductors arranged in parallel are integrally formed by insulating coating with an insulating coating material. In addition, a cut 13 is provided on both surfaces of the insulating coating along the longitudinal direction at an intermediate position between two adjacent rectangular conductors 11 and 11. The width of the margin portions 14, 14 is ½ of the interval between the rectangular conductors 11, 11. Each flat conductor is assumed to have the same width or width and thickness.

  Therefore, n is the number of flat conductors, W is the total width of the flexible flat cable, W is the arrangement pitch (conductor pitch) of the flat conductors, M is the width of the margin portions 14 and 14 of the flexible flat cable, and C is the width of the flat conductor. When the spacing between the flat conductors is G; it is more preferable that the flexible flat cable of the present invention satisfies the following relational expressions 1 to 3.

W = P × n ... 1
P = C + 2 × M 2
G = 2 × M ... 3

  It is preferable that the corner notches 15 of the margin portions 14 and 14 coincide with the shape that appears when the flexible flat cable is cut at the notches 13 and divided or branched.

  The flexible flat cable shown in FIG. 2 can be split or branched by cutting at an intermediate width at an arbitrary location. Divided or branched flexible flat cables have the same margin width and shape, and are easy to attach to the connector.

  The flexible flat cable of the present invention includes, in order from the upstream side to the downstream side, 1) a supply reel group for supplying a flat conductor; 2) a wire concentrator for arranging the supplied flat conductors at a predetermined pitch; 3) an insulating coating material Can be manufactured by using a manufacturing apparatus equipped with an extruder that forms a flexible flat cable including a plurality of flat conductors. In the present invention, the flame retardant resin composition of the present invention is used as the insulating coating material.

  A winding drum is arranged on the downstream side of the extruder, but before that, a cutting machine for dividing the flexible flat cable exiting the extruder by an arbitrary halfway width is arranged, and the flexible divided into two or more Arrange a winder to wind each of the flat cables. The hollow shape of the die is preferably a cross-sectional shape corresponding to the corner notch 15 in the margin and the notch 13 in the insulating coating. When it is difficult to adjust the cross-sectional shape of the die, a jig for forming the corner notch 15 and the insulating notch 13 may be disposed on the downstream side of the die.

  The flexible flat cable of the present invention is suitable for wiring in a narrow space such as wiring of a liquid crystal television or wiring of an electronic device having a movable part. The flexible flat cable of the present invention can be divided or branched using a cut provided in the insulating coating, and can be easily folded or bundled.

  The flexible flat cable insulatively coated with the insulating coating material comprising the flame retardant resin composition of the present invention conforms to the UL standard and is particularly difficult to pass the vertical combustion test VW-1. Has flammability.

  When the flame-retardant resin composition disclosed in Patent Document 4 is used, when the number of flat conductors (number of cores) is relatively small, a flexible flat cable that passes the UL standard vertical combustion test VW-1 is used. Although it can be obtained, when the number of flat conductors is increased, the flame retardancy tends to decrease.

  The flexible flat cable is greatly different from other insulated wires in terms of its overall shape, conductor arrangement, covering state of the insulating coating layer around the conductor, and the like. Therefore, it is presumed that the combustion behavior of the flexible flat cable is different from that of a normal insulated wire having a substantially circular cross section and a single core or a plurality of cores.

  By using the flame retardant resin composition of the present invention as an insulating material, even if it is a multi-core flexible flat cable having 20 or more, more than 60, rectangular conductors, a UL standard vertical combustion test. A flexible flat cable that passes VW-1 can be obtained. By performing insulation coating with the flame-retardant resin composition of the present invention, a flexible flat cable that passes the UL standard vertical combustion test VW-1 can be obtained even if the width and thickness of each rectangular conductor are reduced. .

  The insulating coating layer formed using the flame retardant resin composition of the present invention not only has excellent initial tensile strength and tensile elongation at break, but also has good tensile properties after heat aging. By using the flame-retardant resin composition of the present invention, when measured at a tensile speed of 50 mm / min, a distance between marked lines of 25 mm, and a temperature of 23 ° C. using a tensile tester, 8.2 MPa or more, preferably 9. An insulating coating layer having a tensile strength of 0 to 20.0 MPa, more preferably 9.5 to 18.0 MPa, and a tensile elongation at break of 100% or more, preferably 105 to 230%, more preferably 110 to 200% is obtained. be able to.

  When the tensile strength of the insulating coating layer was measured under the same conditions as described above after a moisture absorption test under a condition of leaving in a constant temperature and high humidity bath at a temperature of 60 ° C. and a relative humidity of 95% for 3 days, the tensile strength was The percentage of tensile strength after moisture absorption relative to the initial value (value before moisture absorption) [referred to as “% residual tensile strength (%)”] is 80% or more, preferably 83 to 99%, and tensile strength after moisture absorption. The retention rate is excellent. The retention rate of tensile strength after moisture absorption is 85 to 99% when an ethylene copolymer other than EVA is used, or when EVA having a vinyl acetate unit content of less than 50% by weight is used. In the case of, it can be increased to 90-98%.

  The insulation coating layer had an initial tensile rupture elongation value (thermal aging test) when the tensile rupture elongation was measured under the same conditions as described above after a heat aging test under a condition of being left in a gear oven at 113 ° C. for 168 hours. The percentage (referred to as the tensile elongation at break (%)) is 75 to 95% of the tensile judgment elongation after the heat aging test with respect to the previous value), indicating excellent heat aging resistance.

  In the flexible flat cable insulated by the insulation coating material comprising the flame retardant resin composition of the present invention, the individually divided samples (samples including one flat conductor) are set in a gear oven at 100 ° C., 60 After preheating for a minute, when pressed from the upper part of the sample with a disk-shaped jig having a load of 250 g and an outer diameter of 9.5 mm for 60 minutes and measuring the residual deformation rate, it is 50% or more, preferably 60% or more, more preferably 70 % Or more, particularly preferably 80% or more of the residual deformation rate. The upper limit of the residual ratio of heat deformation is usually 99% and in many cases about 98%.

  The flexible flat cable coated with an insulating material made of the flame retardant resin composition of the present invention is a sample of individually divided samples (samples containing one flat conductor) left in a low temperature bath at -10 ° C for 4 hours. After that, when the metal rod having a diameter twice as large as the outer diameter of the sample is bent in a U shape at −10 ° C., no crack is generated in the insulating coating layer. That is, the insulating coating layer is excellent in low temperature characteristics (flexibility at low temperature).

  Details of the measurement methods of these various characteristics will be described in Examples, and many of them are in accordance with UL standards. That is, the insulated wire coated with the flame-retardant resin composition of the present invention is suitable as an insulated wire for in-apparatus wiring that satisfies the safety standards of UL standards, including multi-core flexible flat cables, and fire prevention, etc. It is characterized by being environmentally friendly because it is halogen-free while ensuring safety.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited only to these examples. The measurement methods and evaluation methods for various physical properties and characteristics are as follows.

(1) Evaluation of flame retardancy:
According to UL standard 1581, five samples were provided for the vertical combustion test VW-1, and when all five points passed, it was determined as “pass”. The criterion is that if each sample is ignited 15 seconds 5 times, the fire extinguishes within 60 seconds, the absorbent cotton laid on the bottom is not burned by the burning fallen objects, and the kraft paper attached to the top of the sample burns Or that does not burn.

  As a sample, one (60 cores) cut from a flexible flat cable including 60 flat conductors was used. A sample having 5 (5 cores) and 20 (20 cores) flat conductors was cut from the flexible flat cable, and a combustion test was performed in the same manner.

(2) Evaluation of tensile properties:
A tensile test (tensile speed: 50 mm / min, distance between marked lines: 25 mm, temperature: 23 ° C.) was performed on the insulating coating layer, and tensile strength and tensile elongation at break were measured with three samples, and an average value thereof was obtained. According to the UL standard, a material having a tensile strength of 8.2 MPa or more and a tensile elongation at break of 100% or more is determined as “pass”.

(3) Evaluation of tensile strength residual ratio (%) after moisture absorption:
A sample from the insulating coating layer was left in a constant temperature and high humidity bath at a temperature of 60 ° C. and a relative humidity of 95% for 3 days and then taken out, and the tensile strength was measured under the same measurement conditions as described in (2) above. . The percentage of tensile strength after moisture absorption relative to the initial value of tensile strength of the sample (value before moisture absorption) was calculated, and the value was defined as the residual tensile strength ratio (%) after moisture absorption.

(4) Evaluation of heat aging resistance:
A sample from the insulating coating layer was left to stand for 168 hours in a gear oven at a temperature of 113 ° C. for heat aging, and then the tensile elongation at break was measured under the same conditions as described in (2) above. According to the UL standard, the tensile elongation at break [= 100 × (elongation after heat aging / elongation before heat aging)] was calculated. When the tensile elongation at break is 75% or more, the UL standard is satisfied.

(5) Evaluation of low temperature characteristics:
Samples obtained by individually dividing the flexible flat cable (samples including one flat conductor) are left in a low temperature bath of −10 ° C. for 4 hours, and then placed on a metal rod having a diameter twice as large as the outer diameter of the sample. U-bending was performed at 0 ° C., and the presence or absence of cracks in the insulating coating layer was visually determined. Those having no cracks are determined to have a “pass” low-temperature characteristic.

(6) Evaluation of heat deformation resistance:
Samples (samples containing one flat conductor) obtained by dividing each flexible flat cable are set in a gear oven at 100 ° C, preheated for 60 minutes, and a disk shape with an outer diameter of 9.5 mm with a load of 250 g from the top of the sample. After holding for 60 minutes with a jig, the residual deformation rate of the insulating coating layer [= 100 × (thickness after test / thickness before test)] was measured. Those having a heat deformation residual ratio of 50% or more are determined to be “accepted” to the UL standard.

[Example 1]
Using a twin screw mixer (45 mmφ, L / D = 42), each component was melt-mixed with the formulation of Example 1 shown in Table 1 and melt-extruded into a strand, and then the molten strand was cooled and cut. A pellet was prepared. The flame retardant resin composition shown in Table 1 contains stearic acid amide as a lubricant with respect to 100 parts by weight of a polymer component (including a polymer compatibilizer when a polymer compatibilizer is added). 0.5 parts by weight and 1 part by weight of pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] as an antioxidant were blended in common.

  Sixty rectangular conductors (flat tin-plated copper wires) having a width of 0.6 mm and a thickness of 0.1 mm were fed from the supply reel group to the wire concentrator and arranged in parallel at a conductor pitch of 1.0 mm. Next, 60 rectangular conductors arranged in parallel were sent to a die of a melt extruder, and pellets of the flame retardant resin composition shown in Example 1 of Table 1 were melt extruded from the melt extruder to perform insulation coating. The thickness of the insulating coating layer is 0.2 mm, the shape of the cut provided on both sides of the insulating coating is V-shaped (depth 0.13 mm), and the shape of the corner cut at the margin is diagonal. It was a linear shape, and the width of the margin part was (1/2) of the interval between each flat conductor.

  A sample containing 60 flat conductors was cut from the flexible flat cable thus obtained, and a vertical combustion test was performed. A portion corresponding to 5 and 20 rectangular conductors was cut from a sample containing 60 rectangular conductors, and a vertical combustion test was performed. All samples passed the UL vertical combustion test VW-1. The results are shown in Table 1.

[Example 2]
As the flame retardant resin composition, a compounded formulation shown in Example 2 of Table 1 was used. Sixty rectangular conductors (flat tin-plated copper wires) having a width of 0.6 mm and a thickness of 0.1 mm were fed from the supply reel group to the wire concentrator and arranged in parallel at a conductor pitch of 1.0 mm. Next, 60 flat conductors arranged in parallel were sent to a die of a melt extruder, and pellets of the flame retardant resin composition shown in Example 2 of Table 1 were melt extruded from the melt extruder to perform insulation coating. The thickness of the insulating coating layer is 0.2 mm, the shape of the cut provided on both sides of the insulating coating is V-shaped (depth 0.13 mm), and the shape of the corner cut at the margin is diagonal. It was a linear shape, and the width of the margin part was (1/2) of the interval between each flat conductor.

  A sample containing 60 flat conductors was cut from the flexible flat cable thus obtained, and a vertical combustion test was performed. A portion corresponding to 5 and 20 rectangular conductors was cut from a sample containing 60 rectangular conductors, and a vertical combustion test was performed. All samples passed the UL vertical combustion test VW-1. The results are shown in Table 1.

[Examples 3 to 13]
In Example 1, each flexible flat cable was produced like Example 1 except having changed the compounding prescription of the flame-retardant resin composition into the compounding prescription shown in Examples 3-13 of Table 1 and Table 2. did. The results are shown in Tables 1 and 2.

[Comparative Examples 1 to 7]
In Example 1, each flexible flat cable was produced like Example 1 except having changed the compounding prescription of the flame-retardant resin composition into the compounding prescription shown in Comparative Examples 1-7 of Table 3. The results are shown in Table 3.

(footnote)
(1) Adipate type TPU (JIS hardness = A90): A thermoplastic polyurethane elastomer having an adipate type soft segment and a JIS hardness of A90.
(2) PTMG type TPU (JIS hardness = A90): A thermoplastic polyurethane elastomer having a soft segment of polytetramethylene glycol type and a JIS hardness of A90.
(3) EVA-1: an ethylene-vinyl acetate copolymer having a vinyl acetate unit content of 80% by weight.
(4) EVA-2: an ethylene-vinyl acetate copolymer having a vinyl acetate unit content of 46% by weight.
(5) EVA-3: an ethylene-vinyl acetate copolymer having a vinyl acetate unit content of 15% by weight.
(6) An ethylene-ethyl acrylate copolymer having an ethyl acrylate unit content of 23% by weight.
(7) Synthetic magnesium hydroxide: synthetic magnesium hydroxide having an average particle size of 0.8 μm and a BET specific surface area of 6 m ² / g and aminosilane-treated.
(8) Melamine cyanurate: Melamine cyanurate (untreated product) having a particle size in the range of 1 to 5 μm.
(9) Zinc stannate: Zinc stannate having an average particle size of 2.5 μm, a decomposition temperature of 400 ° C. or higher, a tin content of 51 wt%, and a zinc content of 28 wt%.
(10) Zinc hydroxystannate: Zinc hydroxystannate having an average particle size of 2.5 μm, a decomposition temperature of about 200 ° C., a tin content of 41% by weight and a zinc content of 23% by weight.
(11) Zinc oxide: 99.0% or more purity, JIS K 1410 passed product.
(12) Aluminum hydroxide: Aluminum hydroxide having a particle size in the range of 1 to 3 μm, an ignition raw material of 35%, and a 1% by weight dehydration temperature of 240 to 260 ° C.
(13) Lubricant: Stearic acid amide.
(14) Antioxidant: Pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate].
(15) Polymer compatibilizer: Maleic anhydride-modified product of hydrogenated styrene thermoplastic elastomer.

<Discussion>
As shown in Examples 1 to 11, by forming a flame retardant resin composition using a thermoplastic polyurethane elastomer, an ethylene copolymer, and a specific three-component flame retardant, a high degree of flame retardancy is achieved. A flame retardant resin composition that exhibits excellent flexibility, mechanical properties (tensile strength and elongation at break), heat aging resistance, heat deformation resistance, low temperature characteristics (flexibility at low temperatures), and electrical insulation. And a flexible flat cable having an insulating coating layer made of the flame retardant resin composition.

  By including a polymer compatibilizer as a polymer component, the above-mentioned characteristics can be further improved (Examples 12 and 13).

  The insulating coating layer formed using the flame retardant resin composition of the present invention has excellent tensile properties and a high tensile strength residual ratio after moisture absorption. When an ethylene copolymer other than EVA (Example 11) or EVA with a low vinyl acetate unit content (Examples 1-8, 10, 12, and 13) is used as the ethylene copolymer, The tensile strength residual rate can be further increased.

  As shown in Comparative Examples 1 to 5, when a specific three-component flame retardant is not used, not only the flame retardancy with a multi-core is lowered, but also a trade-off relationship with mechanical properties and low temperature properties, A flexible flat cable satisfying the UL standard cannot be obtained. As shown in Comparative Examples 6 and 7, the UL standard cannot be satisfied when an ethylene copolymer is used alone without using a thermoplastic polyurethane elastomer as a polymer component.

  The flame-retardant resin composition of the present invention can be used as an insulating material for forming an insulating coating layer of an insulated wire. The flexible flat cable which carried out the insulation coating of the flame-retardant resin composition of this invention can be utilized as a movable part in an electronic device etc., or an insulated wire in a narrow location.

It is a section schematic diagram of an example of the flexible flat cable of the present invention. It is explanatory drawing which shows an example of the preferable structure of the flexible flat cable of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flexible flat cable 11 Flat conductor 12 Insulation coating layer 13 Notch 14 Margin part 15 Margin part corner notch PO Center point M Margin part width P Conductor pitch C Flat conductor width G Spacing between each flat conductor W Flexible flat cable Full width

Claims (3)

In a flame retardant resin composition containing a polymer component and a flame retardant component,
(1) The polymer component is a weight ratio (A: B) of a thermoplastic polyurethane elastomer (A) having a JIS hardness of less than A98 measured according to JIS K 7311 of Japanese Industrial Standard and an ethylene copolymer (B). In a ratio within the range of 25:75 to 95: 5, and
(2) The flame retardant component is each 100 parts by weight of the polymer component,
40 to 250 parts by weight of magnesium hydroxide (C),
1 to 30 parts by weight of 1,3,5-triazine derivative (D), and a metal compound (E) containing at least one metal atom selected from the group consisting of zinc, aluminum, and tin, and not containing a halogen atom 1 to 30 parts by weight of each flame retardant resin composition.   A flexible flat cable in which a plurality of flat conductors arranged in parallel are collectively covered with an insulating material, and the insulating material is the flame-retardant resin composition according to claim 1. Flat cable.   The flexible flat cable according to claim 2, wherein a cut is provided in both surfaces of the insulating coating layer along the longitudinal direction at an intermediate position between adjacent rectangular conductors.

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