JP2011228189A - Multilayer insulated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer insulated wire using a polyester resin composition containing no halogen compound, which has all of heat resistance, incombustibility, hydrolysis resistance, and abrasion resistance and can achieve the reduction in smoke generation.SOLUTION: A multilayer insulated wire has inside and outside layers over the periphery of a conductor. The inside layer consists of a polyester resin composition including a polyester resin, a polyester block copolymer, a hydrolysis inhibitor, and a calcined clay. The outside layer consists of a polyester resin composition including a polyester resin, a polyester block copolymer, a hydrolysis inhibitor, a calcined clay, and magnesium hydroxide. The polyester block copolymer consists of: 20-70 wt.% of a hard segment containing polybutylene terephthalate as a main ingredient; and 80-30 wt.% of a soft segment consisting of polyester containing a 6-12C straight-chain diol as a diol component.

Description

  The present invention relates to a polyester resin composition mainly composed of a polyester resin and a polyester block copolymer used as an insulating material, and in particular, heat resistance, low smoke generation, flame retardancy, wear resistance, and hydrolysis resistance. It is related with the multilayer insulated wire using the polyester-type resin composition excellent in the.

  Conventionally, an insulating material usually made of polyvinyl chloride resin (PVC) has been used as an electrical insulating material. This PVC insulating material is excellent in that it has high practical characteristics and is inexpensive. However, since harmful gases are generated by fuming, materials other than PVC have recently been demanded. It was.

  Further, in the transportation field such as automobiles and trains, with the reduction in the weight of the vehicle body and the space saving in wiring, there is a demand for lightening and thinning of the electric wires.

  In order to reduce the weight and thickness of such electric wires, when conventional PVC materials are applied, there are problems such as inability to achieve required characteristics such as flame retardancy and wear resistance. Furthermore, in recent years, in order to prevent the great social disruption of fires of high-rise buildings and cable fires stretched around subways and underground shopping centers, it is desired to suppress the generation of smoke during combustion as well as flame retardancy. Yes. In this respect, the PVC material cannot satisfy the requirement.

  On the other hand, polyester resin, which is an engineering plastic polymer, especially polybutylene terephthalate (PBT), is a crystalline polymer and has heat resistance, mechanical strength, gas barrier properties, chemical resistance, wear resistance, low elution, and moldability. It is used in fuel tubes for automobiles, liquid crystal glass polishing apparatus members, semiconductor-related members, etc. (see, for example, Patent Documents 1 to 3).

  Since these engineering plastic polymers have the above-mentioned characteristics, it is expected that the electric wire can be reduced in weight and thickness.

JP 2005-281465 A JP 2006-152122 A JP 2007-45952 A JP 2006-111655 A JP 2006-111873 A JP 2005-213441 A JP 2004-193117 A JP 2001-316533 A Japanese Patent Laid-Open No. 11-1581

  However, the polyester resin is a crystalline polymer, and there is a problem that the degree of crystallinity changes in the manufacturing process or in a specific environment, and it is difficult to suppress the generation of smoke during combustion only with the polyester resin. was there. In particular, crystallization proceeds due to the heat treatment, and there is a concern that the tensile elongation characteristic, which is an important characteristic as an insulating material for electric wires, is deteriorated.

  Patent Documents 4 and 5 report that the degree of crystallization is improved by heat treatment or addition of a crystallization accelerator in order to improve mechanical strength, high-speed moldability, and productivity. However, if the crystallization is promoted, the elongation characteristic may be lowered.

  In Patent Document 6, it is stated that the progress of crystallization can be suppressed by introducing a flexible monomer as a raw material for the polyester resin, but there is no description about the elongation characteristics. Furthermore, in Patent Document 7, it is found that by adding a resin containing a functional group having reactivity with a polyester resin to the polyester resin, the occurrence of crazing is suppressed, the reduction of the dielectric breakdown voltage is reduced, and the high temperature insulating property is excellent. However, no mention is made of the elongation characteristics of the wire insulation by heat treatment.

  Regarding smoke generation, it has been reported in Patent Documents 8 and 9 that magnesium hydroxide is added to achieve improved flame retardancy and low smoke generation, both of which apply a polyolefin resin to the base polymer. Therefore, it is considered difficult to reduce the thickness of the wire insulator.

  Accordingly, an object of the present invention is to provide a multilayer insulated wire using a polyester resin composition that does not contain a halogen compound that has heat resistance, flame retardancy, hydrolysis resistance, and abrasion resistance and can achieve low smoke generation. There is.

In order to achieve the above object, the present invention provides an inner layer comprising a polyester resin composition containing a polyester resin, a polyester block copolymer, a hydrolysis inhibitor, and a calcined clay on the outer periphery of a conductor, and a polyester resin and a polyester block. A multilayer insulated wire comprising a copolymer, a hydrolysis inhibitor, calcined clay, and an outer layer made of a polyester-based resin composition containing magnesium hydroxide, wherein the polyester block copolymer has terephthalic acid as a dicarboxylic acid Hard segment (a) 20 to 70% by mass comprising 60% by mole or more of polybutylene terephthalate as a main component, and 99 to 90% by mole of an aromatic dicarboxylic acid and 6 to 12 carbon atoms in the acid component constituting the polyester Linear aliphatic dicarboxylic acid 1 to 10 mol%, diol component is carbon Soft segment consisting of the polyester is 6-12 straight chain diol (b) in the polyester block copolymer of 80 to 30 mass%, the melting point (T) is the following formula (1)
TO-5>T> TO-60 (1)
(TO: melting point of polymer composed of components constituting hard segment)
It is a polyester block copolymer in the range of.

  The inner layer is a polyester resin composition containing 50 to 150 parts by weight of a polyester block copolymer, 2 to 7 parts by weight of a hydrolysis inhibitor, and 0.5 to 5 parts by weight of calcined clay with respect to 100 parts by weight of a polyester resin. It is preferable that

  The outer layer is 50 to 150 parts by weight of a polyester block copolymer, 2 to 7 parts by weight of a hydrolysis inhibitor, 0.5 to 5 parts by weight of calcined clay, and 10 to 30 parts of magnesium hydroxide with respect to 100 parts by weight of the polyester resin. A polyester resin composition containing parts by weight is preferable.

  The polyester resin is preferably polybutylene naphthalate or polybutylene terephthalate.

  The hydrolysis inhibitor is preferably an additive having a carbodiimide skeleton.

  The thickness of the inner layer and the outer layer is preferably 0.1 to 0.5 mm.

  The multilayer insulated wire of the present invention is very excellent in terms of heat resistance, low smoke generation, wear resistance, flame resistance, and hydrolysis resistance.

In this invention, it is a figure explaining the IEC combustion test method of an electric wire. (A) is a side view which shows the abrasion tester of an electric wire in this invention, (b) is a side view which shows the abrasion tester of an electric wire.

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

  The present invention includes an inner layer composed of a polyester resin composition containing a polyester resin, a polyester block copolymer, a hydrolysis inhibitor, and a calcined clay on the outer periphery of the conductor, a polyester resin, a polyester block copolymer, and a hydrolysis inhibitor. And an outer layer made of a polyester-based resin composition containing a baked clay and magnesium hydroxide.

  Here, each component will be described.

  Examples of the polyester resin used in the present invention include PBT resin, polytrimethylene terephthalate resin, polyethylene naphthalate resin, and polybutylene naphthalate resin.

  The polybutylene naphthalate resin (PBN) in the present invention is a polyester having naphthalene dicarboxylic acid, preferably naphthalene-2,6-dicarboxylic acid as the main acid component and 1,4-butanediol as the main glycol component, It is a polyester in which all or most of the repeating units (usually 90 mol% or more, preferably 95 mol% or more) are butylene naphthalene dicarboxylate.

  In addition, the polyester can be copolymerized with the following components as long as the physical properties are not impaired. For example, as the acid component, aromatic dicarboxylic acids other than naphthalenedicarboxylic acid, such as phthalic acid, isophthalic acid, terephthalic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylmethanedicarboxylic acid, diphenylketonedicarboxylic acid, Examples thereof include diphenyl sulfide dicarboxylic acid, diphenyl sulfone dicarboxylic acid, aliphatic dicarboxylic acid such as succinic acid, adipic acid, sebacic acid, and alicyclic dicarboxylic acid such as cyclohexane dicarboxylic acid, tetralin dicarboxylic acid, decalin dicarboxylic acid and the like.

  As glycol components, ethylene glycol, propylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, neopentyl glycol, cyclohexanedimethanol, xylylene glycol, diethylene glycol, polyethylene glycol, bisphenol A, catechol, resorcinol Examples include diol, hydroquinone, dihydroxy diphenyl, dihydroxy diphenyl ether, dihydroxy diphenyl methane, dihydroxy diphenyl ketone, dihydroxy diphenyl sulfide, dihydroxy diphenyl sulfone and the like.

  Examples of the oxycarboxylic acid component include oxybenzoic acid, hydroxynaphthoic acid, hydroxydiphenylcarboxylic acid, and ω-hydroxycaproic acid.

  A compound having three or more functional groups such as glycerin, trimethylpropane, pentaerythritol, trimellitic acid, pyromellitic acid and the like may be copolymerized as long as the polyester does not substantially lose molding performance.

  Such a polyester is obtained by polycondensing naphthalenedicarboxylic acid and / or a functional derivative thereof with butylene glycol and / or a functional derivative thereof using a conventionally known aromatic polyester production method.

  Further, the terminal carboxyl group concentration of PBN used in the present invention is not particularly limited, but a smaller one is desirable.

  The polybutylene terephthalate resin as a polyester resin used in the present invention is a polyester having a repeating unit of butylene terephthalate as a main component, 1,4-butanediol as a polyhydric alcohol component, and terephthalic acid as a polyvalent carboxylic acid component. Or it is polyester which makes the main repeating unit the butylene terephthalate unit obtained using the ester-forming derivative. A main repeating unit means that a butylene terephthalate unit is 70 mol% or more in all the polyhydric carboxylic acid-polyhydric alcohol units. Further, the butylene terephthalate unit is preferably 80 mol% or more, more preferably 90 mol%, particularly 95 mol% or more.

  Examples of polyvalent carboxylic acid components other than terephthalic acid used in polybutylene terephthalate resin include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, isophthalic acid, phthalic acid, trimesic acid, trimellitic acid, etc. Aromatic polycarboxylic acids, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid and other aliphatic dicarboxylic acids, cyclohexanedicarboxylic acid and other alicyclics Examples thereof include dicarboxylic acids or ester-forming derivatives of the above polyvalent carboxylic acids (for example, lower alkyl esters of polyvalent carboxylic acids such as dimethyl terephthalate). These polyvalent carboxylic acid components may be used alone or in combination.

  On the other hand, examples of polyhydric alcohol components other than 1,4-butanediol include aliphatic polyhydrides such as ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, pentanediol, hexanediol, glycerin, trimethylolpropane, and pentaerythritol. Monohydric alcohols, alicyclic polyhydric alcohols such as 1,4-cyclohexanedimethanol, aromatic polyhydric alcohols such as bisphenol A and bisphenol Z, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene oxide glycol, etc. Examples include polyalkylene glycol. These polyhydric alcohol components may be used alone or in combination.

  The polybutylene terephthalate resin used in the present invention has a terminal carboxyl group equivalent of 50 (eq / T) or less, preferably 40 (eq / T) or less, more preferably 30 (from the viewpoint of hydrolysis resistance. eq / T) or less. When the terminal carboxyl group equivalent exceeds 50 (eq / T), it is not preferable from the viewpoint of hydrolyzability.

  The polybutylene terephthalate resin of the present invention may be used alone or a plurality of mixtures having different terminal carboxyl group concentrations, melting points, catalyst amounts, etc., as long as the requirements of the present invention are satisfied.

  The polyester block copolymer used in the present invention is composed of polybutylene terephthalate as a main constituent of 60 mol% or more of the hard segment (a), but also aromatic dicarboxylic acid containing benzene or naphthalene ring other than terephthalic acid. Diols such as aliphatic dicarboxylic acids having 4 to 12 carbon atoms, aliphatic diols having 2 to 12 carbon atoms other than tetramethylene glycol, and alicyclic diols such as cyclohexanedimethanol may be copolymerized. The polymerization rate is less than 30 mol%, preferably less than 10 mol%, based on the total dicarboxylic acid. The smaller the copolymerization ratio, the higher the melting point and the better. However, copolymerization is also performed to increase flexibility. However, when the copolymerization ratio is increased, the compatibility between the polyester block copolymer and the polybutylene naphthalate resin is lowered, and the wear resistance, which is a subject of the present invention, may be impaired.

  On the other hand, the soft segment (A) is an aromatic dicarboxylic acid 99 to 90 mol%, a straight chain aliphatic dicarboxylic acid 1 to 10 mol% having 6 to 12 carbon atoms, and the diol component is a straight chain having 6 to 12 carbon atoms. It is a polyester that is a chain diol.

  Aromatic dicarboxylic acids include terephthalic acid and isophthalic acid.

  Examples of the linear aliphatic dicarboxylic acid having 6 to 12 carbon atoms include adipic acid and sebacic acid. The amount of the linear aliphatic dicarboxylic acid is 1 to 10 mol%, more preferably 2 to 5 mol%, based on the total acid component of the polyester constituting the soft segment (a). If it is 10 mol% or more, the compatibility with the polybutylene naphthalate resin and the wear resistance are lowered. On the other hand, at 1 mol% or less, the softness of the soft segment (a) is impaired, and as a result, the flexibility of the polyester resin composition is impaired.

  The diol component is a straight chain diol having 6 to 12 carbon atoms.

  The polyester constituting the soft segment (a) needs to be amorphous or low crystalline. Therefore, it is preferable that isophthalic acid be used for 20 mol% or more of the total acid component constituting the soft segment (A). The soft segment (a) can be copolymerized with some other components in the same manner as the hard segment (a). However, since the compatibility with the polybutylene naphthalate resin (A) is lowered and the wear resistance which is the subject of the present invention is impaired, the amount of the copolymer component is 10 mol% or less, preferably 5 mol% or less.

  In the polyester block copolymer of the present invention, the mixing ratio of the hard segment (A) and the soft segment (A) is 20 to 70% by mass of the hard segment (A) and 80 to 30% by mass of the soft segment (A). Good. Moreover, the amount ratio is 20-50: 80-50, Preferably it is 25-40: 75-60. These quantity ratios are not preferred because the resulting polyester block copolymer has more hard segments (a) and is harder and difficult to use. If there are many soft segments (A) This is because crystallinity is reduced and handling becomes difficult.

  In addition, the segment length of the soft segment and hard segment of the polyester block copolymer is approximately 500 to 7000, preferably 800 to 5000, expressed as molecular weight, but is not particularly limited. Although it is difficult to directly measure the segment length, for example, the composition of the polyester constituting soft and hard, the melting point of the polyester comprising the components constituting the hard segment, and the melting point of the obtained polyester block copolymer From this, it can be estimated using the Flory equation.

From such points, the melting point of the polyester block copolymer of the present invention is an important item,
The melting point (T) is the following formula (1)
TO-5>T> TO-60 (1)
(TO: melting point of polymer composed of components constituting hard segment)
It is good to be in the range.

  That is, the melting point (T) should be between TO-5 and TO-60, preferably between TO-10 and TO-50, more preferably between TO-15 and TO-40. The melting point is 10 ° C., preferably 20 ° C. or more higher than the melting point (T ′) of the random copolymer. When the melting point of the random copolymer is not determined, it is 150 ° C. or more, preferably 160 ° C. It is good to set it as the above melting | fusing point.

  When the polymer of the present invention is not a block copolymer but a random copolymer, the polymer is generally amorphous and has a low glass transition temperature. The surface is not sticky and cannot be used as a real problem.

  Examples of the method for producing such a polyester block copolymer include a method in which polymers constituting the soft segment and the hard segment are produced and melt-mixed so that the melting point is lower than that of the polyester constituting the hard segment. Since this melting point changes depending on the mixing temperature and time, it is preferable to deactivate the catalyst by adding a catalyst deactivator such as phosphorus oxyacid when the target melting point is reached.

  The polyester block copolymer of the present invention is applicable to those having an intrinsic viscosity of 0.6 or more, preferably 0.8 to 1.5, measured in 35 ° C. orthochlorophenol. If the intrinsic viscosity is lower than this, the strength is lowered, which is not preferable.

  The addition amount of the polyester block copolymer of this invention is 50-150 weight part with respect to 100 weight part of polybutylene naphthalate resin. When the addition amount is less than 40 parts by weight, the heat resistance is poor, and when it exceeds 150 parts by weight, the wear resistance is lowered. More preferably, it is 50-150 weight part, and the more excellent heat resistance effect can be acquired by setting it as 50 weight part or more.

  The hydrolysis inhibitor used in the present invention is a compound having a carbodiimide skeleton such as dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, and is not particularly limited.

  The addition amount is 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight with respect to the polyester resin. When the amount is less than 0.5 parts by weight, the durability of the present invention cannot be fully exhibited, and when the amount added is more than 5 parts by weight, the flexibility is lost when the wire is processed, and the wire moves to the surface of the wire. It will lead to the cause of poor appearance.

The inorganic porous filler used in the present invention preferably has a specific surface area of 5 m ² / g or more.

  The addition amount is preferably 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight with respect to the polyester resin. If the content is too small, ions cannot be trapped sufficiently, resulting in a low insulation resistance. On the other hand, if the amount is too large, dispersibility and tensile properties are lowered, which is not preferable.

  The inorganic porous filler may be not only calcined clay but also zeolite, mesalite, anthracite, perlite foam, activated carbon.

  Magnesium hydroxide used in the present invention is not particularly limited, and fatty acid, fatty acid metal salt, vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropyltriethoxysilane, aminopropyl Surface treatment may be performed with trimethoxysilane, aminopropyltriethoxysilane, or the like, or an untreated product may be used.

  The addition amount is 10 to 30 parts by weight, more preferably 15 to 20 parts by weight with respect to the polyester resin. When the amount added is less than 10 parts by weight, the low smoke generation effect that is the effect of the present invention cannot be sufficiently exhibited, and when the amount added is more than 30 parts by weight, flexibility and wear resistance when processed into an electric wire. Sex is reduced.

  As a method of blending the above-mentioned various components into the polybutylene naphthalate resin, it can be performed by a known means at an arbitrary stage until immediately before the coating production. As the simplest method, a method in which a polybutylene naphthalate resin, a polyester-polyester elastomer, a hydrolysis inhibitor, a calcined clay, and the like are formed into pellets by melt mixing extrusion is employed.

  Further, pigments, dyes, fillers, nucleating agents, mold release agents, antioxidants, stabilizers, antistatic agents, lubricants, and other known additives can be blended and kneaded in the resin composition of the present invention. .

  In the polyester-based resin composition of the present invention, a thermoplastic resin other than the polybutylene naphthalate resin can be blended within a range that does not impair the effects of the present invention. Examples thereof include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate, polypropylene resins, polyethylene resins, and the like.

  The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

  Table 1 shows the blended composition of the polyester-based resin composition studied in the present invention, and Table 2 shows the results of evaluation using the blended composition.

[Electric wire manufacturing]
The obtained polyester resin compositions (A) and (B) were dried in a hot air thermostat bath at 130 ° C. for 8 hours, and the polyester resin composition (A) was directly added to a tin-plated annealed copper wire having a diameter of 1.2 mm. Extrusion was performed with a coating thickness of 1 mm. Further, the polyester resin composition (B) was extruded on the outer periphery of the electric wire with a coating thickness of 0.15 mm. For extrusion molding, dies and nipples with diameters of 4.2 mm and 2.0 mm were used, respectively, and the extrusion temperature was 250 ° C. to 270 ° C. for the cylinder portion and 265 ° C. for the head portion. The take-up speed was 10 m / min. In the electric wire manufacturing method, two layers may be extrusion coated simultaneously.

  Evaluation in Table 2 was performed as follows.

[Hydrolysis resistance test]
The sample from which the core wire of the produced electric wire was removed was left in a constant temperature and humidity chamber of 85 ° C./85% RH for 30 days. Thereafter, a tensile test was carried out, and those having a residual elongation rate of 70% or more were evaluated as ◯ (passed), and those having a residual elongation rate of less than 70% were evaluated as x (failed).

[Flame retardance]
The flame resistance of the electric wires was tested in a combustion test. The produced electric wire was tested according to the IEC combustion test method (IEC603332-1). As shown in FIG. 1, the electric wire 10 is held vertically by the upper support portion 15 and the lower support portion 16, and the flame of the burner 17 is 475 ± 5 mm from the upper support portion 15 with respect to the electric wire 10 and 45 °. After applying the flame for a specified burning time at an angle of, the burner 17 was removed, the flame was extinguished, and the carbonized portion 10c was examined.

When the distance from the upper support part to the carbonized part 10c is 50 mm or more at the upper part of the electric wire (α) and 540 mm or less at the lower part of the electric wire (β), it is acceptable (◯), and other than the above range is rejected (×). .

[Abrasion test]
The applied wire is reciprocated by contacting the wear needle 20a with the insulator 12 of the wire 10 while applying a load 9N (weight 20b) with the wear tester 20 shown in FIG. The power supply 22 is applied between the ten conductors 11 and the wear needle 20a, and the number of reciprocations until the wear needle 20a contacts the conductor 11 and short-circuits is measured.

  When the number of reciprocations was 150 or more, it was judged as acceptable (O), and when it was less than 150, it was judged as unacceptable (x).

[Fume concentration test]
According to IEC60695-6-30, the light impermeability due to smoke was measured. Measured by framing method. The thickness of the test piece was 0.5 mm.

  A smoke concentration of less than 100 was regarded as acceptable (◯), and 100 or more was regarded as unacceptable (x).

[DC stability test]
According to EN 50305.6.7, DC 300 V is applied in 85 ° C., 3% NaCl aqueous solution. Electricity was continuously applied for 10 days. Those that did not break down were evaluated as acceptable (◯), and those that failed (×).

[Elongation after heat treatment]
For the elongation after the heat treatment, a heat aging test was performed, and then a tensile test was performed to measure heat aging characteristics.

Heat aging test;
The sample from which the core wire of the produced electric wire was removed was heat-treated at 150 ° C./96 h in a constant temperature bath and left at room temperature for about 12 hours, and then a tensile test was performed. Heat treatment shall comply with JISC3005.

Heat aging characteristics;
The sample produced by the thermal aging test was measured at a tensile speed of 200 mm / min. The tensile test shall comply with JISC3005. Those having an elongation remaining rate ((initial elongation / elongation after heat aging) × 100) of 70% or more were evaluated as “◯” (passed), and those having an elongation remaining rate of less than 70% were evaluated as “x” (failed).

  From Table 2, Comparative Example 1 is rejected in terms of flame retardancy and smoke generation because the amount of magnesium hydroxide added in the outer layer is less than the amount added in the present invention.

  In Comparative Example 2, since the amount of magnesium hydroxide added in the outer layer is large, the flame resistance and smoke generation are good, but the wear resistance and the residual elongation after heat treatment do not reach the target values.

  Moreover, in the comparative example 3, since the hydrolysis inhibitor is not added to outer layer mixing | blending, hydrolysis resistance is disqualified. Further, the wear resistance was also rejected.

  Further, in Comparative Example 4, since the fired clay was not added to both the inner layer and the outer layer, the DC stability test was rejected.

  In Comparative Example 5, the amount of the polyester block copolymer added to the outer layer was larger than the range of the present invention, so the material became soft and the wear resistance was unacceptable.

  In Comparative Example 6, the hydrolysis resistance was not acceptable because no hydrolysis inhibitor was added to the inner layer formulation.

  In Comparative Example 7, the addition amount of the polyester block copolymer blended with the inner layer was less than the range of the present invention, so that the residual elongation after heat treatment was low and failed.

  In Comparative Example 8, the amount of addition of the polyester block copolymer blended with the inner layer was larger than the range of the present invention, so the wear resistance was rejected.

  On the other hand, in Examples 1-10, since it was in the range of the present invention, it was a result of passing in all characteristics.

  In this embodiment, the structure of the insulated wire covering the insulating layer on the central conductor has been described. However, the present invention is not limited to this structure, and the cable group in which these insulated wires are gathered together with the resin composition of the present invention is sheathed. It can also be used as a so-called cable sheath material covered with (jacket).

  In the present embodiment, the central conductor is described as a single wire, but the present invention is not limited to this, and may be a stranded wire structure in which a plurality of single wires are twisted together, or a structure in which a plurality of single wires are simply gathered together. There may be.

  Further, in this embodiment, an annealed copper wire is used as the material of the central conductor, but the present invention is not limited to this. A hard copper wire or a copper alloy wire (for example, Cu—Sn alloy wire, Cu—Ag alloy wire, Cu— Sn-In alloy wire).

  In the present embodiment, the material for plating the central conductor is tin, but the present invention is not limited to this. Pb—Sn alloy, Sn—Ag—Cu alloy, Sn—Ag—Cu—P alloy, Sn -Cu-P alloy, Sn-Cu alloy, Sn-Bi alloy, etc. can also be used.

DESCRIPTION OF SYMBOLS 10 Electric wire 11 Conductor 12 Insulator 17 Burner 20 Abrasion tester 20a Abrasion needle 20b Weight 300 Base

Claims (6)

On the outer periphery of the conductor, an inner layer made of a polyester resin composition containing a polyester resin, a polyester block copolymer, a hydrolysis inhibitor, and fired clay;
A multilayer insulated wire comprising a polyester resin, a polyester block copolymer, a hydrolysis inhibitor, a calcined clay, and an outer layer made of a polyester-based resin composition containing magnesium hydroxide,
The polyester block copolymer has a terephthalic acid content of 20 to 70% by mass of polybutylene terephthalate whose main component is 60 mol% or more per dicarboxylic acid component, and the acid component constituting the polyester is an aromatic dicarboxylic acid. Soft segment (A) 80 comprising 99 to 90 mol% of acid, 1 to 10 mol% of linear aliphatic dicarboxylic acid having 6 to 12 carbon atoms, and diol component being a linear diol having 6 to 12 carbon atoms Polyester block copolymer of ˜30% by mass, melting point (T) is the following formula (1)
TO-5>T> TO-60 (1)
(TO: melting point of polymer composed of components constituting hard segment)
A multilayer insulated wire characterized by being a polyester block copolymer in the range of   The polyester resin composition in which the inner layer contains 50 to 150 parts by weight of a polyester block copolymer, 2 to 7 parts by weight of a hydrolysis inhibitor, and 0.5 to 5 parts by weight of calcined clay with respect to 100 parts by weight of the polyester resin. The multilayer insulated wire according to claim 1, wherein:   The outer layer is 50 to 150 parts by weight of a polyester block copolymer, 2 to 7 parts by weight of a hydrolysis inhibitor, 0.5 to 5 parts by weight of calcined clay, and 10 to 30 parts of magnesium hydroxide with respect to 100 parts by weight of the polyester resin. The multilayer insulated wire according to claim 1 or 2, which is a polyester resin composition containing parts by weight.   4. The multilayer insulated wire according to claim 1, wherein the polyester resin is polybutylene naphthalate or polybutylene terephthalate.   The multilayer insulated wire according to any one of claims 1 to 4, wherein the hydrolysis inhibitor is an additive having a carbodiimide skeleton.   The multilayer insulated wire according to any one of claims 1 to 5, wherein the inner layer and the outer layer have a thickness of 0.1 to 0.5 mm.