JP2013041838A - Fluorine-containing elastomer coated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorine-containing elastomer coated wire improved in flame retardant and considering environment.SOLUTION: In a fluorine-containing elastomer wire having a core wire size of 22 AWG or less and an insulator thickness of 0.4 mm or more, a composition is formed at an outer periphery of a conductor as a coating layer, the composition being obtained by adding, relative to 100 pts.mass of a tetrafluoroethylene-propylene-based copolymer, 0.5-20 pts.mass of one or two or more flame retardant assistants selected from among zinc stannate, zinc borate, calcium borate and melamine cyanurate. The coated wire after heat aging has a tensile strength retention of 80% or more and an elongation retention of 80% or more.

Description

  The present invention relates to a fluorine-containing elastomer-coated electric wire using a tetrafluoroethylene-propylene copolymer.

  Conventionally, tetrafluoroethylene-propylene copolymers have been used as coating materials for electric wires that require high heat resistance and flexibility.

  Tetrafluoroethylene-propylene copolymer has excellent flexibility, thermal stability, electrical insulation, heat resistance, oil resistance, chemical resistance, and flame resistance, and is a crosslinkable fluorine-containing elastomer copolymer. It is a coalescence.

   This copolymer was coated on the conductor or the outer periphery of the electric wire, and heat-crosslinked with peroxide, or irradiated and irradiated with ionizing radiation to obtain a fluorine-containing elastomer-coated electric wire (Patent Document 1). ~ 4).

JP-A 63-284713 Japanese Patent Laid-Open No. 10-116521 JP-A-6-181008 JP-A-8-315646 JP 2000-129049 A JP 2003-227975 A

  However, in the case of a small-sized electric wire such as a device electric wire, for example, an electric wire of 22 AWG (American Wire Gauge) or less, the core wire diameter and the insulator thickness in a severe flame-retardant test such as UL standard VW-1 Some combinations do not pass. For such special sizes, there is a technique to increase the flame retardancy by adding a chlorinated or brominated flame retardant, but there is a tendency to regulate these flame retardants due to the recent trend of environmental protection.

  Therefore, in order to solve the above-mentioned problems, the present invention is to provide a fluorine-containing elastomer-coated electric wire that further improves flame retardancy and is environmentally friendly.

  In order to achieve the above object, the invention of claim 1 is directed to a fluoroelastomer electric wire having a core wire size of 22 AWG or less and an insulator thickness of 0.4 mm or more, and 100 mass of tetrafluoroethylene-propylene copolymer. A composition obtained by adding 0.5 to 20 parts by mass of one or more flame retardant aids selected from zinc stannate, zinc borate, calcium borate, and melamine cyanurate to a part of the conductor. The coated electric wire formed as a coating layer on the outer periphery is a fluorine-containing elastomer-coated electric wire characterized by having a residual tensile strength ratio of 80% or more and a residual elongation ratio of 80% or more after heat aging.

  The invention according to claim 2 is the fluorine-containing elastomer-coated electric wire according to claim 1, wherein the coating layer is subjected to a crosslinking treatment using a crosslinking agent or by irradiation with an electron beam or ultraviolet rays.

  The invention according to claim 3 is the fluorine-containing fluorine according to claim 1 or 2, wherein 5 to 35 parts by mass of a filler made of silica or calcium carbonate is added to 100 parts by mass of the tetrafluoroethylene-propylene copolymer. It is an elastomer covered electric wire.

  According to this invention, the effect which can obtain the fluorine-containing elastomer covering electric wire excellent in the flame retardance is exhibited.

  Hereinafter, a preferred embodiment of the present invention will be described in detail.

  The tetrafluoroethylene-propylene copolymer itself has high flame retardancy.

  However, in the case of an electric wire structure having a core wire size of 22 AWG or less (conductor diameter of 0.6438 mm or less) and an insulator thickness of 0.4 mm or more, the vertical flame retardant property such as UL VW-1 may not be satisfied. .

  Therefore, in the present invention, one or more flame retardant aids selected from zinc stannate, zinc borate, calcium borate, and melamine cyanurate are added to 100 parts by mass of the tetrafluoroethylene-propylene copolymer. It has been found that by adding 0.5 to 20 parts by mass, flame retardancy is improved without impairing mechanical properties and heat resistance.

  In general, the addition of a flame retardant causes a decrease in the heat aging characteristics, but the present invention can obtain both the flame retardant characteristics and the heat aging characteristics by selecting the flame retardant.

  The amount of addition of these flame retardant aids is limited to 0.5 to 20 parts by mass. If the amount is less than 0.5 parts by mass, there is no effect on flame retardancy. This is because there is no flame retardant effect, but rather the heat resistance is lowered. More preferably, it is 5-15 mass parts.

  The tetrafluoroethylene-propylene copolymer is composed of tetrafluoroethylene and propylene, which are main components, and components copolymerizable therewith.

  Components copolymerizable with tetrafluoroethylene and propylene include, for example, ethylene, butene-1, isobutene, acrylic acid and its alkyl ester, methacrylic acid and its alkyl ester, vinyl fluoride, vinylidene fluoride, hexafluorobropen, Examples include chloroethyl vinyl ether, glycidyl vinyl ether, chlorotrifluoroethylene, and perfluoroalkyl vinyl ether.

  The tetrafluoroethylene-propylene copolymer preferably has a molar ratio of tetrafluoroethylene to propylene in the range of 90 / l0 to 45/55 from the viewpoints of heat resistance and moldability. The content of components other than the main component is desirably in the range of 30 mol% or less with respect to the main component.

  It is desirable to irradiate the electric wire obtained above with an electron beam, ultraviolet light, or the like, or to perform a crosslinking treatment using a known method using an organic peroxide.

  In the present invention, in addition to the above-described components, a crosslinking aid, a flame retardant aid other than the above, an antioxidant, a lubricant, a stabilizer, a filler, a colorant, silicone, and the like may be added.

  According to the above configuration, it is possible to obtain a fluorine-containing elastomer-coated electric wire having excellent flame retardancy even for a small-sized thick electric wire.

  The present invention can be applied to a core wire size of 22 AWG to 30 AWG as a small sized thick electric wire.

  The present invention can be applied as a rubber packing or seal material that requires heat resistance in addition to the wire coating material.

(Examples 1-5)
The compounding agents shown in Table 1 are uniformly kneaded with a roll heated to 50 to 60 ° C. for 15 minutes to form a compound.

  In Table 1, Aphras 150E, 150C, and 150CS manufactured by Asahi Glass Co., Ltd., which are tetrafluoroethylene-propylene copolymers, each have a fluorine content of 57%. The average particle size of zinc borate, calcium borate, zinc stannate, and melamine cyanurate as a flame retardant aid is preferably 10 μm or less.

  Thereafter, this compound is press-fitted into a 40 mm extruder (L / D = 24) in which the head is set to 120 ° C., the first cylinder is set to 80 ° C., and the second cylinder is set to 120 ° C. Thereafter, a coating layer is formed by extruding to a thickness of 0.55 mm on the outer periphery of a copper stranded wire of 26AWG (conductor diameter 0.4094 mm, 0.16 mm strand 7 strands), and steam of 12 atm is applied to this coating layer. By cross-linking, a fluorine-containing elastomer covered electric wire is produced.

  Comparative Examples 1-5 are also produced by the same method as in the examples.

  Next, mechanical properties, flame retardancy, and heat aging resistance of each of the fluorine-containing elastomer-coated wires prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated.

Evaluation of each holding property was performed by the method shown below.
(1) Tensile properties Tensile strength (MPa) and elongation (%) were measured by conducting a tensile test in accordance with JIS-K-6301 on the coating layer obtained by removing the conductor from each fluorine-containing elastomer-coated electric wire. The values of tensile strength and elongation in this tensile test are taken as initial values.
(2) Flame retardancy A vertical combustion test (VW-1) based on UL subject 758 was conducted, and self-extinguishing within 1 minute was accepted, and over 1 minute was rejected.
(3) Heat aging resistance (heat resistance)
The coating layer obtained by removing the conductor from each fluorine-containing elastomer-coated electric wire was held in a gear oven (232 ° C.) with an air displacement of 200 times / hr for 7 days, and then subjected to a tensile test according to JIS-K-6301. The tensile strength residual rate (%) and the elongation residual rate (%) relative to the initial value were measured.

  Table 1 shows the test results for the respective fluorine-containing coated electric wires produced in Examples 1 to 5 and Comparative Examples 1 to 5.

  As shown in Table 1, each of the fluorine-containing elastomer-coated wires of Examples 1 to 5 according to the present invention has a tensile strength of 12 MPa or more, an elongation of 350% or more, a flame retardance, and after heat aging. The tensile strength residual rate is 80% or more and the elongation residual rate is 80% or more, which is excellent in all of mechanical properties, flame retardancy, and heat resistance.

  On the other hand, in Comparative Examples 1 and 3, 5 the flame retardant aid was less than the specified amount of 5 parts by mass, and the flame retardancy was rejected. In Comparative Example 2 and Comparative Example 4, the flame retardant aid exceeded the specified amount of 20 parts by mass, and the flame retardancy passed, but the heat aging resistance was significantly lowered and was lower than the target of 80%.

Claims (3)

  In a fluorine-containing elastomer electric wire having a core wire size of 22 AWG or less and an insulator thickness of 0.4 mm or more, zinc stannate, zinc borate, calcium borate with respect to 100 parts by mass of the tetrafluoroethylene-propylene copolymer After the heat aging, the covered electric wire in which a composition obtained by adding 0.5 to 20 parts by mass of one or more flame retardant aids selected from melamine cyanurate is formed as a coating layer on the outer periphery of the conductor. A fluorine-containing elastomer-coated electric wire characterized by having a tensile strength residual ratio of 80% or more and an elongation residual ratio of 80% or more.   The fluorine-containing elastomer-coated electric wire according to claim 1, wherein the coating layer is subjected to a crosslinking treatment using a crosslinking agent or by irradiation with an electron beam or ultraviolet rays.   The fluorine-containing elastomer covered electric wire according to claim 1 or 2, wherein 5 to 35 parts by mass of a filler made of silica or calcium carbonate is added to 100 parts by mass of a tetrafluoroethylene-propylene copolymer.