JP5727267B2 - Low dielectric constant extruded product - Google Patents

Description

  The present invention provides insulation for electronic and electrical components that are required to have a low dielectric constant even when they are in a water absorption or moisture absorption state, such as insulated wires, heat shrinkable tubes, connectors, and CPU connectors. The present invention relates to a molded product such as a heat-shrinkable tube and a connector used for coating, and an insulated wire insulated and coated with the molded product.

  Insulated wires that are stored and used in areas with high-temperature and high-humidity climates such as Japan and Asia may have low water absorption and low hygroscopic properties so that the electrical properties do not deteriorate due to water absorption or moisture absorption. Desired. Polyolefin resins, such as polyethylene, have a low dielectric constant of 2.2-2.3 and low water absorption, so that excellent electrical characteristics can be maintained even under high humidity.

  On the other hand, in insulated wires used for wiring and routing in automobile parts such as automobiles and ships, industrial machines such as robots, electronic equipment, etc., contact with other members during assembly, and even when used with other members due to vibration, etc. Therefore, the insulating coating material is required to have high wear resistance. However, polyolefin resins such as polyethylene generally have low wear resistance.

  In order to satisfy the requirements of low water absorption and abrasion resistance, for example, as proposed in Japanese Patent Laid-Open No. 4-368715 (Patent Document 1), a polyolefin resin having a Shore D hardness of 50 or more is used. . However, even in the case of a high-hardness polyolefin-based resin, as shown in the examples, since it has a Shore D hardness of about 60 at most, the insulation coating material for insulated wires of the above equipment has a further improvement in wear resistance. Desired.

  In order to satisfy a high degree of wear resistance, for example, in Japanese Unexamined Patent Application Publication No. 2002-124138 (Patent Document 2) and Japanese Unexamined Patent Application Publication No. 2002-140939 (Patent Document 3), an insulating inner layer mainly composed of polyethylene and An insulating coating having a two-layer structure with an insulating outer layer mainly composed of a polyamide resin having excellent wear properties has been proposed. Japanese Patent Laid-Open No. 2010-198898 (Patent Document 4) proposes to use a mixture of a polyolefin resin and a polyamide resin as a main component as an insulating coating member used for automobile wiring. In some cases, it is shown that one layer can satisfy wear resistance, trauma resistance, and flame retardancy. However, Patent Document 4 does not describe the influence of water absorption.

  In addition, cold cathode fluorescent lamps are used as the light source of the backlight used for the display of liquid crystal panels of liquid crystal televisions, copying machines, computers, etc., and the high frequency, high voltage current generated by the lighting circuit is used. The cold cathode tube is supplied. As the power supplied to the cold cathode tube is increased in frequency and voltage, it is necessary to reduce the leakage current of the insulated wires used for these by reducing the dielectric constant of the insulating layer. In Japanese Patent Application Laid-Open No. 2010-118207 (Patent Document 5), as a fuel-insulated electric wire used for such wiring in an electronic device, a first insulating layer covering the outer periphery of a conductor is mixed with a mixture of a styrene elastomer and a polyolefin resin. It has been proposed to be composed of a material having a dielectric constant of 3.2 or less in a mixture with polyphenylene ether. In patent document 5, the insulation 2nd layer is further provided on the insulation 1st layer, and it does not describe about the influence of the electrical property by water absorption.

  Further, shielded wires are used in places where shielding against noise is required among electric wires arranged in automobiles. This shield wire includes a plurality of signal wires and an insulated wire and a ground drain wire, and the drain wire and the insulated wire are sequentially covered with a shield layer and a sheath made of an insulating resin material. The end portion of this is peeled off from the sheath and the shield layer, and then water-stopped. In JP 2008-234974 A (Patent Document 6), the sheath of the terminal part and the skinned end of the shield layer are covered with a heat-shrinkable tube for the purpose of slimming the terminal part of the shield wire and improving the shielding performance. A water stop structure for drain wires covered with hot melt tubes is proposed. The heat-shrinkable tube used in such a water-stopping structure has a high wear resistance because it can be reduced in potential characteristics even when the peeled end is exposed to moisture, and may come into contact with other members during assembly. Is also necessary.

Furthermore, with the increase in the frequency of computer transmission signals, insulating members used in connection parts that are deeply involved in high-speed electrical signal transmission, such as CPU connectors for high frequencies, have a lower dielectric constant. Therefore, a member having excellent dielectric characteristics is required. Furthermore, along with the space saving due to the downsizing of computers, connectors are also required to be smaller and thinner, and as a connector material, not only insulation and low dielectric constant, but also high strength is required. The
Therefore, aliphatic polyamides such as nylon 46 and nylon 12, which have high strength and excellent properties such as heat resistance, chemical resistance, and moldability, are more frequently used as insulating members for electrical and electronic parts such as connectors. ing. However, polyamide is generally highly hygroscopic based on the hydrophilicity of the amide group and has a property of absorbing water according to the atmosphere. Polyamides such as nylon 46 and nylon 12 greatly increase the dielectric constant and dielectric loss tangent due to moisture absorption. Therefore, a polyamide having a low water absorption rate has been studied.

  For example, Japanese Patent Laid-Open No. 2000-67985 (Patent Document 7) discloses a dicarboxylic acid having a melting point measured by DSC of 280 ° C. or higher, 45 to 100 mol% of dicarboxylic acid being terephthalic acid, and 80- A polyamide composed of 100% by mole of a diamine which is an aliphatic diamine (a mixture of 1,9-diaminononane and 2-methyl-1,8-diaminooctane in the examples) has been proposed.

  Japanese Patent Application Laid-Open No. 2008-189929 (Patent Document 8) discloses a polyamide obtained by polymerizing an aliphatic polyamide such as polyamide 613 and hexamethylenediamine and terephthalic acid and / or isophthalic acid as a low water-absorbing polyamide. A polyamide molding material in which a filler such as glass fiber is blended with the above mixture has been proposed.

JP-A-4-368715 JP 2002-124138 A JP 2002-140939 A JP 2010-198898 A JP 2010-118207 A JP 2008-234974 A JP 2000-67985 A JP 2008-189929 A

  As described above, it is difficult to provide wear resistance and an insulating material with polyolefin alone. On the other hand, with respect to polyamide, for example, a polyamide having a melting point of 280 ° C. or higher as proposed in Patent Document 7, it is necessary to perform extrusion molding at 280 ° C. or higher. May cause decomposition. Further, in the polyamide resin proposed in Patent Document 8, even if the water absorption rate can be reduced by adding a filler, the excellent properties inherent in polyamide are not utilized for the mechanical properties such as elongation. There is.

  The present invention has been made in view of such circumstances. The object of the present invention is high strength (high hardness) and can maintain a low dielectric constant and a low dielectric loss tangent even under high humidity storage. An object of the present invention is to provide an insulating material, a molded article such as a connector and a heat-shrinkable tube, and an insulated wire using the insulating coating material.

As a result of studying various polyamides, the present inventors have found that a polyamide having a specific monomer composition can maintain a low dielectric constant and a low dielectric loss tangent even by water absorption and moisture absorption, thereby completing the present invention. That is, the low dielectric constant extruded product of the present invention comprises an aliphatic dicarboxylic acid having an average carbon number of 13 or more containing at least 50 mol% of dimer acid and a diamine containing 50 mol% or more of monocyclic alicyclic diamine. An extruded product obtained by extruding a composition mainly composed of polyamide formed by polycondensation ,
The dielectric constant after drying is 3.3 or less, and the dielectric constant after being immersed in water at room temperature for 1 week is 1.1 times or less the dielectric constant during drying .

Before SL dimer acid is preferably derived from a plant.

  The alicyclic diamine is preferably a 1,3-diaminocyclohexane derivative, particularly preferably isophorone diamine. The polyamide is preferably an amorphous polyamide.

  The insulated wire of the present invention is one in which the outer periphery of a conductor is insulated and coated with any of the extruded products of the present invention.

  The present invention further includes a heat-shrinkable tube obtained by further expanding the diameter of the extruded product of the present invention extruded into a tube shape and fixing the expanded state, and a connector having the extruded product of the present invention as a housing. Is also included.

  Since the extruded product of the present invention uses a specific polyamide as a raw material, the dielectric constant during drying is low, and the dielectric constant increase due to water absorption and moisture absorption is small.

  Although embodiments of the present invention will be described below, it should be considered that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

<Polyamide for low dielectric constant extrusion products>
First, the polyamide that is the main component of the low dielectric constant extruded material of the present invention will be described.

  The polyamide used in the present invention is a polyamide obtained by polycondensation of a diamine containing 50 mol% or more of an alicyclic diamine and an aliphatic dicarboxylic acid having an average carbon number of 13 or more, and has a low dielectric constant and also by water absorption. Polyamide with small increase in dielectric constant. Preferably, the dielectric constant when dried is 3.3 or less, more preferably 3.0 or less, and the dielectric constant after being immersed in water at 25 ° C. for 1 week is within 1.1 times the dielectric constant when dried. It is preferable that it is within 1.05 times. Here, the dielectric constant at the time of drying means the state after leaving for 10 hours in a 40 degreeC thermostat.

  Examples of the alicyclic diamine that is a raw material monomer for polyamide include isophorone diamine (corresponding to 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane), cyclohexanediamine, methylcyclohexanediamine, 1,3-bis ( Monocyclic alicyclic hydrocarbon derivatives such as aminomethyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane; bis- (3-methyl-4-aminocyclohexyl) methane, bis- (4-aminocyclohexyl) methane Bis- (4-aminocyclohexyl) -2,2′-dimethylpropane, bis (4-aminocyclohexyl) methane, bis (4-aminocyclohexyl) propane, bis (3-methyl-4-aminocyclohexyl) methane, bis (3-Methyl-4-aminocyclohexyl) propane Bis (3,5-dimethyl-4-aminocyclohexyl) methane, bis (3,5-dimethyl-4-aminocyclohexyl) propane, bis (3-methyl-4-amino-5-ethylcyclohexyl) methane, bis ( 3-methyl-4-amino-5-ethylcyclohexyl) propane, bis (3,5-diethyl-4-aminocyclohexyl) methane, bis (3,5-diethyl-4-aminocyclohexyl) propane, bis (3-methyl -4-amino-5-isopropylcyclohexyl) methane, bis (3-methyl-4-amino-5-isopropylcyclohexyl) propane, bis (3,5-diisopropyl-4-aminocyclohexyl) methane, bis (3,5- Diisopropyl-4-aminocyclohexyl) propane, bis (3-ethyl-4-amino) Cyclohexyl) methane, bis (3-ethyl-4-aminocyclohexyl) propane, bis (3-isopropyl-4-aminocyclohexyl) methane, bis (3-isopropyl-4-aminocyclohexyl) propane, etc. Type alicyclic hydrocarbon derivatives; condensed ring type alicyclic hydrocarbon derivatives such as bisaminomethylnorbornene; one or more cyclic amines such as bis (aminopropyl) piperazine and bis (aminoethyl) piperazine It can be used by mixing. Of these, alicyclic diamines having a branched structure, such as isophorone diamine and bis (3-methyl-4aminocyclohexyl) methane, and alicyclic diamines having functional groups at asymmetric positions of the ring structure are crystallized. A 1,3-diaminocyclohexane derivative is preferred, and isophoronediamine is more preferred because it has a large inhibitory effect and tends to reduce the dielectric constant during drying and suppress the increase in dielectric constant due to water absorption and moisture absorption.

  In addition to the alicyclic diamine, it should be within a range that does not impair the influence of the electrical properties of the polyamide due to water absorption (specifically, 50 mol% or less, preferably 30 mol% or less, more preferably 20 mol% or less of the diamine compound). For example, aliphatic diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4 / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine; lactams such as ε-caprolactam, ω-lauryllactam, 2-pyrrolidone; amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid; metaxylylenediamine, paraxylenediamine aromatic diamine, It may be used as a copolymerization monomer. Furthermore, isocyanates such as tolylene diisocyanate can also be used.

As the dicarboxylic acid serving as a raw material monomer for polyamide, an aliphatic dicarboxylic acid having an average carbon number of 13 or more is used. It may be a saturated fatty acid, an unsaturated fatty acid, or a hydrogenated product of an unsaturated fatty acid. Specifically, aliphatic dicarboxylic acids having 13 or more carbon atoms such as tetradecanedicarboxylic acid (C ₁₂ H ₂₄ (COOH) ₂ ); dimer acids obtained by dimerizing fatty acids; two or more fats having an average carbon number of 13 or more A mixture of a group dicarboxylic acid can be used.

Here, the mixture of two or more kinds of aliphatic dicarboxylic acids having an average carbon number of 13 or more means that an aliphatic dicarboxylic acid having 13 or more carbon atoms and an aliphatic dicarboxylic acid having less than 13 carbon atoms have an average carbon number of 13 or more. It is a mixture that is combined so that The combination is not particularly limited. For example, a mixture of suberic acid (C ₈ H ₁₄ O ₄ ) and dimer acid, a mixture of adipic acid (C ₆ H ₁₀ O ₄ ) and dimer acid, sebacic acid (C ₁₀ H ₁₈ O ₄₎ ) And dimer acid, and a mixture of dimer acid, such as azelaic acid (C ₉ H ₁₆ O ₄ ) and dimer acid, is preferably used. The mixing ratio of the aliphatic dicarboxylic acid having 13 or more carbon atoms and the aliphatic dicarboxylic acid having less than 13 carbon atoms can be set as appropriate depending on the type of the dicarboxylic acid, but is preferably dimer. The acid content is preferably 50 mol% or more.

The above dimer acid, generally an unsaturated fatty acid having 8 to 24 carbon atoms, mainly oleic acid _{(C 18 H 34 O 2)} , linoleic acid _{(C 18 H 32 O 2)} , linolenic acid (C ₁₈ H ₃₀ O ₂ ) is a dimerized polymerized fatty acid, and may contain a monomer or trimer in addition to the dimer. It may be a dimer of a single unsaturated fatty acid, or dimerized several types of unsaturated fatty acids (natural, preferably plant-derived fatty acids such as tall oil fatty acid, soybean oil fatty acid, palm oil fatty acid). It may be. Further, it may be a cyclic dimer acid or an acyclic dimer acid. In general, if the content of linoleic acid (C ₁₈ H ₃₂ O ₂ ) and linolenic acid (C ₁₈ H ₃₀ O ₂ ) is large, a relatively large amount of cyclic dimer acid is likely to be generated.

  Of the dicarboxylic acids having an average carbon number of 13 or more, dicarboxylic acids having a carbon number of 20 or more are preferred. As the number of carbons increases, the dielectric constant during drying tends to be low, and a polyamide having a low dielectric constant can be obtained. As a dicarboxylic acid having a large number of carbon atoms, dimer acid can be preferably used from the viewpoint of easy availability. Furthermore, since dimer acid of plant-derived fatty acid has a short raw material production cycle (6 months to 1 year), securing raw materials Can be preferably used since it is easy. On the other hand, a dicarboxylic acid having a low carbon number tends to easily obtain a high-hardness polyamide, so that the dicarboxylic acid as a polyamide constituent monomer can be appropriately selected according to the use of the molded product and the required characteristics. Good.

  As a polycondensation method of a diamine and a dicarboxylic acid, a conventionally performed method can be used. Specifically, the diamine and the dicarboxylic acid are, for example, 150 to 250 ° C. in the presence of a polymerization initiator. What is necessary is just to heat at about and polycondensate for about 3 to 10 hours. Further, the heating may be performed under reduced pressure.

  The polyamide as described above has a water absorption rate of 0.3% by weight or more after standing in a constant temperature bath at 40 ° C. for 10 hours, depending on the type of constituent monomer, and the water absorption rate after being immersed in water at room temperature for 7 days. Is 0.6% by weight or more, which is water-absorbing and hygroscopic compared to the polyamide currently used as the main component of the insulating material. However, despite the fact that it is a highly water-absorbing and highly hygroscopic polyamide, it has a low dielectric constant, and even after being immersed in water at room temperature for 7 days, it is preferably not more than 1.1 times the dielectric constant during drying. It is suppressed to 1.05 times or less.

  Although the polyamide is water-absorbing and hygroscopic, the reason for its low dielectric constant is not clear, but the combination of alicyclic diamine and aliphatic dicarboxylic acid is difficult to crystallize, the polyamide molecular chains cannot be aligned, and random It will exist in a state. As a result, the amide bond of the polyamide molecular chain that contributes to the dielectric constant is also in a random direction (amorphous), so the coordination between the amide bond and the water molecule is unlikely to occur, contributing to an increase in the dielectric constant Guess that is small.

<Molded product>
The low dielectric constant extruded product of the present invention is obtained by extruding a resin composition mainly composed of polyamide having the above-described configuration.

The resin composition may contain a resin other than polyamide, an additive, and the like, if necessary, as long as the effects of the present invention are not impaired.
Examples of resins other than polyamide resin include hydrocarbon polymers such as polyethylene, polypropylene, polystyrene, styrene-butadiene copolymer, cyclic polyolefin, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate. Copolymers, ethylene copolymers such as ethylene-butyl acrylate copolymers, ethylene-methyl methacrylate copolymers, and polymers obtained by copolymerizing maleic anhydride, acrylic acid, glycidyl ether, etc. with the ethylene copolymers , Polymers obtained by grafting maleic anhydride or acrylic acid onto the polymer, engineering plastics such as polyethylene terephthalate, polyethylene butyrate, polyphenylene ether, polybutylene succinate, and polylactic acid Etc. Any biodegradable polymers may be exemplified. The content is less than 30% by weight of the resin component, more preferably less than 10% by weight. Examples of the additives include pigments, dyes, antioxidants, light stabilizers, plasticizers, flame retardants, lubricants, fillers, silane coupling agents, trimethylolpropane trimethacrylate and triallyl isocyanurate. And monomers.

  The extrusion molding is a molding method in which the resin composition is melted and extruded by an extruder. In addition to narrow extrusion molding in which a die giving a desired shape is passed and continuously molded, T-die extrusion molding, atypical molding Examples include extrusion, inflation molding in which air is blown into an extruded resin, and injection molding in which a mold cavity is filled with a molten resin.

  Examples of the extrusion-molded article of the present invention include an insulating coating for an insulated wire, a heat-shrinkable tube used for a water-stop structure at the peeled end of a shielded wire, and a housing for electrical and electronic component connectors.

The obtained molded product may be crosslinked by irradiating with ionizing radiation. Irradiation with ionizing radiation causes intermolecular and intramolecular cross-linking of the polymer, improving the heat resistance and wear resistance of the molded product.
Examples of ionizing radiation sources include accelerated electron beams, γ rays, X rays, α rays, and ultraviolet rays. Accelerated electron beams are most preferably used from the viewpoint of industrial use, such as ease of use of the radiation source, transmission thickness of ionizing radiation, and speed of crosslinking treatment.
The acceleration voltage of the accelerating electron beam may be appropriately set depending on the thickness of the molded product. For example, in a molded product having a thickness of 0.01 mm to 1.5 mm, the acceleration voltage is selected between 200 and 2000 kV. An irradiation dose of 20 to 500 kGy provides a sufficient degree of crosslinking.

[Insulated wire]
The insulated wire of the present invention uses the extruded product of the present invention as a conductor insulating film.
As the conductor, a copper or copper alloy wire, a tin-plated wire, a nickel-plated wire, an aluminum wire, magnesium, iron, nickel, or other metal conductor is used. In addition to the strands, a strand obtained by twisting a plurality of strands, or a strand that is compressed after being twisted can be used.

  The forming method for forming the insulating coating on the outer periphery of the conductor is appropriately selected according to the type of the insulated wire. For example, in the case of electric wire coating, the outer periphery of the conductor may be manufactured by extrusion molding so as to cover the resin composition using a crosshead die or the like.

  You may bridge | crosslink the obtained insulated wire by irradiating ionizing radiation. Irradiation with ionizing radiation can cause intermolecular and intramolecular cross-linking of the polymer in the insulating coating, thereby improving the heat resistance and wear resistance of the insulating coating.

The insulated wire according to the present invention is made of a material having a low dielectric constant, a dielectric constant and the like that are hardly affected by water absorption, and has a Shore D hardness of 60 or more. Therefore, it is used as wiring and signal lines in places where wear resistance and trauma resistance are required due to contact with other parts, such as transportation equipment such as automobiles and ships, elevators, robots, etc. It is suitable as an insulated wire.
In addition, it has low dielectric constant, electrical characteristics such as dielectric constant are not easily affected by water absorption, and has high hardness, so that it satisfies the characteristics required for a single-layer insulation coating that directly covers the outer periphery of the conductor. Therefore, it is possible to satisfy the demand for thinning the insulating coating, and further reducing the size and slimness of the electric wire. Therefore, as insulated wires used for wiring of automobiles and electrical equipment that are required to be small and light, and for electronic devices such as liquid crystal televisions, copiers, computers, etc., there is a demand for miniaturization and thinning. Is also suitable.

〔connector〕
The low dielectric constant extruded product of the present invention has a low dielectric constant, and electrical characteristics such as dielectric constant are less affected by water absorption, etc., so it is also suitable as a connector housing for working electronic parts that operate at high speed. It is. A connector having a low dielectric constant can reduce troubles in electrical signal transmission due to dielectric loss.

  Here, the connector is a connection tool for connecting circuits or devices to each other, generally a piece of metal called a contact that makes electrical connection in contact with the other side, an insulator that supports them, insertion, It consists of an auxiliary mechanism for facilitating removal and fixing. The extruded product of the present invention is used for an insulator portion that supports an electrical connection site.

  The connector may be manufactured by melting the resin composition and molding the resin composition into a desired shape using a mold, such as an injection molding method or an extrusion molding method.

[Heat shrink tube]
The heat-shrinkable tube of the present invention is a tube-shaped product that is obtained by extruding a resin composition containing polyamide as a main component into a tube shape, and can shrink to a predetermined diameter by heating. Such a heat-shrinkable tube is cooled after it is expanded to a predetermined outer diameter by a method such as introducing compressed air into the tube while the polyamide is heated to a temperature equal to or higher than the softening point of the polyamide. Fix the shape.

  After extrusion, it is preferable to crosslink by irradiating with ionizing radiation. The diameter expansion and contraction characteristics as a coating material are improved by irradiation crosslinking with ionizing radiation. The expansion ratio is preferably about 1.2 to 5 times. The thickness of the tubular molded product is not particularly limited, but is preferably 0.01 to 1.5 mm.

  The type of the extruder is not particularly limited, and any of a screw type and a non-screw type may be used, but a screw type is preferable. Although the kind of screw is not particularly limited, the ratio (L / D) of the total length L to the cylinder hole diameter D is usually preferably about 15 to 40. The die withdrawal rate (DDR) is not particularly limited, but is preferably about 1 to 20. The heater temperature may be a temperature at which the polyamide composition to be used can be uniformly softened and melted, specifically, a temperature about 20 ° C. higher than the softening point.

  The heat-shrinkable tube of the present invention can be shrunk at 80 to 110 ° C. by cross-linking, depending on the type of polyamide as the main component, and has little influence on electrical properties such as dielectric constant due to water absorption and moisture absorption. Therefore, it can be used for water-insulating treatment of the insulation coating at the site where the wire coating is peeled and connected, such as a wire harness, and the skinned terminal of the shield wire. For example, a hot melt tube is placed on the peeled end of the shield wire, a heat shrink tube is covered, the heat shrink tube is heated and shrunk by heating, the hot melt tube is melted, and the hot melt resin is contained in the shield wire. The terminal portion can be water-stopped by infiltrating and filling between the drain wires.

  The best mode for carrying out the present invention will be described with reference to examples. The examples are not intended to limit the scope of the invention.

[Measurement and evaluation methods]
First, the measurement and evaluation methods performed in this example will be described. In addition, all the following measurements were performed under 25 degreeC and 25% of humidity.
(1) Melting point Using a DSC-50 manufactured by Shimadzu Corporation, the melting point was confirmed by heating to 25-300 ° C at 10 ° C / min. Here, the melting point is defined as the temperature at which the heat of crystal melting is 1 cal / g or higher when measured at a temperature increase rate of 10 ° C./min. None. In addition, when two melting peaks appeared, both were taken as melting points.

(2) Measurement of relative dielectric constant (ε) and tan δ The impedance and tan δ were measured using an impedance analyzer 4 (4276A (LCZ meter) manufactured by Yokogawa Hewlett-Packard) under the condition of a frequency of 1 kHz.
The relative dielectric constant was determined by converting the measured sheet thickness, the dielectric constant in vacuum, and the measurement area.

(3) Volume resistivity (ρ)
The volume specific resistance (Ω · cm) was measured using a 4329A High Resistance meter manufactured by Yokogawa Hewlett-Packard.

(4) Water absorption rate (% by weight)
By heating to 190 ° C. by the Karl Fischer method, the amount of water contained in the sample sheet was measured, and the weight ratio to the sheet weight before drying was calculated.

(5) Transparency Three layers of sheet-like molded products having a thickness of 1 mm were laminated and placed on a sheet to which characters were applied, and the characters were confirmed. The case where the character could be read was indicated as “◯”, and the case where the character was not read was indicated as “X” because the transparency was inferior.

(6) Shore D hardness Measured using a durometer (Asker rubber hardness meter D type: manufactured by Kobunshi Keiki Co., Ltd.).

(7) Degree of water absorption effect of ε The relative dielectric constant (b) after being immersed in water for 1 week, compared to the relative dielectric constant (a) after being dried for 10 hours in a constant temperature bath at 40 ° C. (during drying) The increase rate (b / a) was calculated.

[Polyamide No. Synthesis of 1-4 and 11-15]
Use isophorone diamine (IPDA) or 1,3-bis (aminomethyl) cyclohexane (1,3-BAC) as the alicyclic diamine component, or hexamethylene diamine (HMDA) as the aliphatic diamine, and dimer as the dicarboxylic acid component Either acid, sebacic acid or adipic acid is blended in the quantitative ratios (molar ratios) shown in Tables 1 and 2, polycondensed at 200 ° C. for 3 hours, and further reacted for 1 hour under reduced pressure.

  As the dimer acid, Tsunodim 395 (monomer / dimer / trimer = 2.5 / 94 / 3.5) manufactured by Tsukuno Food Industry Co., Ltd. was used.

[Polyamide No. 5-8, 16]
These polyamides are commercially available products, and the main dicarboxylic acids and diamines as polyamide constituents are as follows.
・ No. 5: Nylon 11, “Rilsan (registered trademark) B ESN-TL”
Polyamide raw material is Undecaractam No. 6: Nylon 12, “UBESTA (registered trademark) 3035JU3” manufactured by Ube Industries, Ltd.
Polyamide raw material is lauryl lactam no. 7: SealerPA,
The main raw material monomers for polyamide are terephthalic acid, isophthalic acid, hexamethylenediamine 8: Genesta G1300H
The main raw material monomers for polyamide are terephthalic acid, nonanediamine 16: TR90
The main raw material monomer of polyamide is dodecanedicarboxylic acid, 4,4'-methylenebis (2-methylcyclohexylamine)

[Preparation of polyamide resin sheet]
Polyamide No. synthesized above. 1-4, 11-15, and commercially available polyamide (No. 5-8, 16) were mixed with a mixing roll and press-molded to produce a sheet having a thickness of 1 mm.
After the sheet produced using polyamide was left in a constant temperature bath at 40 ° C. for 10 hours, the relative dielectric constant, tan δ, volume resistivity, water absorption rate, Shore D hardness, and transparency were measured based on the above measurement method. Furthermore, after being immersed in water at room temperature for 1 week and left to stand for 14 days under high humidity (40 ° C., 90%), the relative dielectric constant, tan δ, volume resistivity and water absorption were measured, and the relative dielectric constant was measured. The water absorption effect was calculated. The measurement results are shown in Table 1 and Table 2 together with the constitution and melting point of each polyamide.

  In addition, sample sheet | seat No. using the polyamide which uses the diamine which contains 50 mol% or more of dicarboxylic acids with an average carbon number of 13 or more and alicyclic diamine as a constituent monomer. 1,11-15 corresponds to an embodiment of the present invention.

  In Table 1, no. 3 is a case where an aliphatic diamine is used as a diamine which is a polyamide constituent monomer. The dielectric constant at the time of drying was 3.12, which is a value that satisfies the low dielectric constant, but after immersion for 1 week, the dielectric constant increased 1.37 times that at the time of drying, and in the water absorption and moisture absorption states The electrical characteristics cannot be satisfied. In this respect, when the diamine contains 50 mol% or more of an alicyclic diamine (No. 1, 2, 4), the water absorption influence is 1.1 times or less, and the dielectric constant due to water absorption and moisture absorption is low. It can be seen that the increase is suppressed.

  Regarding commercial products, no. 5 and 6 are cases where lactam is used as a polyamide raw material, and since it does not contain alicyclic diamine, the dielectric constant upon drying is as high as 3.7 or higher. It is unsuitable for use as an insulating material for storage and use.

  No. 7 and 8 are cases where an aromatic dicarboxylic acid such as terephthalic acid and / or isophthalic acid is used as a constituent monomer, and an alicyclic diamine is not substantially used as a diamine. Neither of them has a high dielectric constant when dried and cannot be used for applications requiring a low dielectric constant.

  On the other hand, a polyamide sheet No. 1 synthesized with an aliphatic dicarboxylic acid using a diamine containing 50 mol% or more of an alicyclic diamine. In Nos. 1, 2, and 4, No. 1 using sebacic acid having 10 carbon atoms. Nos. 2 and 4 are Nos. Using dimer acid having 13 or more carbon atoms. Compared to 1, the dielectric constant at the time of drying was as high as 3.3 or more.

No. 11-15 is a case where an alicyclic diamine is used as a constituent monomer and a mixture of a dimer acid and a dicarboxylic acid having less than 13 carbon atoms is used as an aliphatic dicarboxylic acid. Belonging to a functional polyamide.
No. 16 is a case where dodecanedicarboxylic acid having 12 carbon atoms is used as the dicarboxylic acid, and a symmetrical alicyclic diamine is used as the diamine. No. The initial dielectric constant of 16 was 2.98, which was a low dielectric constant, but the dielectric constant after water absorption was 1.1 times or more that before water absorption. No. 1 using a dicarboxylic acid containing 50 mol% or more of the above dicarboxylic acid (dimer acid). 11-15, no. It was bigger than 1.

  No. 11-13 is the case where a mixture of dimer acid and sebacic acid is used as the dicarboxylic acid and the mixing ratio is changed. It can be seen that the higher the content of dimer acid, the lower the dielectric constant during drying. No. 11 and no. From the comparison of No. 15, even when the content of dimer acid is the same, the average carbon number is lowered by changing the type of dicarboxylic acid to be mixed. No. 15 is No. The dielectric constant during drying was higher than 11. Therefore, it can be seen that the higher the average carbon number of the dicarboxylic acid, the lower the dielectric constant polyamide insulating material can be provided.

  No. Comparing 11 and 14, No. using IPDA as diamine. No. 11 had a lower dielectric constant during drying and a smaller water absorption effect.

  No. 1-8 and 11-16 both have a Shore D hardness of 60 or more and can satisfy wear resistance, but satisfy the requirement that the dielectric constant is low and the increase in dielectric constant is small due to water absorption and moisture absorption. No. corresponding to the example. It was 1,11-15. As for the Shore D hardness, the smaller the average carbon number of the dicarboxylic acid, the higher the Shore D hardness tends to be (Comparison of No. 1-3, Comparison of No. 11-13). It can be seen that the dicarboxylic acid may be selected according to the use of the product, such as the degree of storage and the storage conditions under high humidity conditions.

  The low dielectric constant extruded product of the present invention has a low dielectric constant and can be used as an insulating coating material for insulated wires and electrical / electronic parts used under high humidity because it only requires little increase in the dielectric constant due to water absorption and moisture absorption. . Moreover, since it is high hardness and transparent, it can be used suitably also for the insulated wire used for vehicles, such as a motor vehicle, and industrial equipment, such as a robot, with which abrasion resistance and a damage resistance are calculated | required. In particular, when the extruded product of the present invention is used as an insulating coating, it is possible to prevent wear characteristics, deterioration of electrical properties due to water absorption or moisture absorption with only the insulating coating single layer structure, and thus thinning the insulating coating. Therefore, it can be suitably used for an insulated wire used for wiring of OA equipment that is required to be small and light, such as a computer and a copying machine.

Claims (8)

A composition comprising, as a main component, a polyamide obtained by polycondensation of an aliphatic dicarboxylic acid having an average carbon number of 13 or more containing at least 50 mol% of dimer acid and a diamine containing 50 mol% or more of a monocyclic alicyclic diamine. a extrusion to moldings out ing press,
A low dielectric constant extruded product having a relative dielectric constant of 3.3 or less when dried and a dielectric constant of 1.1 times or less of the dielectric constant after drying for 1 week in water at room temperature. The dimer acid is a low dielectric constant extrudate of claim 1 is derived from a plant. The low dielectric constant extruded product according to claim 1 or 2, wherein the monocyclic alicyclic diamine is a 1,3-diaminocyclohexane derivative. The low dielectric constant extruded product according to claim 3 , wherein the monocyclic alicyclic diamine is isophorone diamine. The low dielectric constant extruded product according to any one of claims 1 to 4 , wherein the polyamide is an amorphous polyamide. The insulated wire by which the outer periphery of a conductor is insulation-coated with the extrusion molding of any one of Claims 1-5 . A heat-shrinkable tube obtained by further expanding the diameter of the extruded product according to any one of claims 1 to 5 extruded into a tube shape and fixing the expanded state. The connector which uses the extruded product of any one of Claims 1-5 as a housing.