JP2012117044A - Thermally conductive resin composition and molded article made of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermally conductive resin composition excellent in flexibility, impact resistance and the like as well as in heat resistance and resistance to moist heat.SOLUTION: The thermally conductive resin composition includes copolymerized polyester resin A and thermally conductive filler B. The capacity ratio A/B between A and B ranges from 30/70 to 90/10, and A contains aromatic dicarboxylic acid and dimer acid as acid components and contains 1,4-butanediols and polybutadiene glycols as glycol components. The content of the dimer acid in the acid components ranges from 10 to 50 mol%, the content of 1,4-butanediols in the glycol components is not less than 80 mol%, and the content of polybutadiene glycols in the glycol components ranges from 1 to 20 mol%.

Description

  The present invention relates to a resin composition excellent in thermal conductivity, and relates to a thermal conductive resin composition excellent in flexibility and impact resistance, and further excellent in workability during melt molding.

  In recent electronic devices, with high performance, miniaturization and weight reduction, heat countermeasures that effectively dissipate the heat generated in various electronic components to the outside has become a very important issue. There is a growing demand for improvement in heat dissipation of resin molding materials.

Conventionally, as a means of improving the heat dissipation of the resin molding material, a filling material having high thermal conductivity, that is, heat of boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, zinc oxide, silicon carbide, graphite, etc. A method of blending a conductive filler is known.
For example, Patent Document 1 describes a thermally conductive resin molded product in which graphite powder is blended with a thermoplastic resin, and Patent Document 2 describes a resin heat radiation plate in which magnesium oxide or aluminum oxide is blended with polyphenylene sulfide resin. Yes. However, in order to obtain a highly heat-conductive resin composition, it is necessary to add a large amount of heat-conductive filler, which significantly reduces the moldability of the resin composition and limits its application. There was a problem.

  As a method for improving the processability of a resin composition in which a large amount of such a filler is added, a method of adding a plasticizer to the resin composition is known. However, when a plasticizer is added to the resin composition, the strength is remarkably lowered and the plasticizer bleeds out.

  On the other hand, a polyester resin, especially a copolymer polyester resin mainly composed of polyethylene terephthalate or polybutylene terephthalate and copolymerized with an aliphatic dicarboxylic acid or various glycols, has excellent heat resistance, weather resistance, solvent resistance, and flexibility. Therefore, they are widely used as films, fibers, sheets, adhesives, and sealants.

  In a resin composition containing a large amount of a filler, in order to increase the melt fluidity of the base resin, for example, it is conceivable to lower the molecular weight of the copolymerized polyester resin. However, when the molecular weight is lowered, there is a problem that the resin becomes brittle. For this reason, there is a problem that flexibility and impact resistance at a low temperature and a normal temperature are lacking.

  In order to improve such a defect, a method of copolymerizing a soft segment with a polyester resin has been considered. A polyester-polyether block copolymer having a polyether compound as a soft segment has a low glass transition point of the resin, high fluidity, and the resin is flexible even when the molecular weight is reduced. For this reason, it is widely used as a material such as a molding material used in electric / electronic parts or automobile parts. Such a polyester-polyether block copolymer is disclosed in Patent Document 3, for example.

  However, this polyester-polyether block copolymer is susceptible to hydrolysis due to the ester bond of the hard segment, and the polyether compound that is a soft segment is likely to undergo oxidative degradation, thermal decomposition, etc. when exposed to high temperatures. As a result, there were problems in the heat resistance durability and moisture resistance durability of the copolymer itself.

JP-A-62-131033 JP 2001-151905 A JP-A-2-3429

  The present invention solves the above-mentioned problems, and in a thermally conductive resin composition containing a large amount of filler, it improves brittleness and achieves flexibility and impact resistance at room temperature. It is a technical problem to provide a heat conductive resin composition that is excellent in heat resistance and heat and moisture resistance, and is excellent in fluidity during melting and injection molding at low pressure. It is an object of the present invention to provide a heat conductive resin composition that can be molded into a thin-walled or complicated part.

As a result of studies to solve the above problems, the present inventors have found that the above problems can be solved by using a resin composition containing a copolyester resin having a specific composition, and have reached the present invention. That is, the gist of the present invention is as follows.
(1) It contains a copolymerized polyester resin (A) and a thermally conductive filler (B), and the volume ratio (A / B) between (A) and (B) is 30/70 to 90/10. It is a certain resin composition, (A) contains aromatic dicarboxylic acid and dimer acid as acid components, and contains 1,4-butanediol and polybutadiene glycols as glycol components. The content of dimer acid is 10 to 50 mol%, the content of 1,4-butanediol in the glycol component is 80 mol% or more, and the content of polybutadiene glycols in the glycol component is 1 to 20 A thermally conductive resin composition characterized by being a mol%.
(2) The thermally conductive filler (B) is at least one selected from flaky graphite, flaky boron nitride having a hexagonal crystal structure, aluminum oxide, magnesium carbonate, zinc oxide, and talc. The heat conductive resin composition according to (1).
(3) A molded article obtained by molding the thermally conductive resin composition according to (1) or (2).
(4) A sealing material for electric / electronic parts containing the heat conductive resin composition according to (1) or (2).
(5) An electrical / electronic component sealed with the sealing material described in (4) above.

The thermally conductive resin composition of the present invention has excellent flexibility and impact resistance at room temperature, improved brittleness, and can be used for various applications such as films, fibers, sheets, and adhesives. .
Furthermore, since the heat conductive resin composition of the present invention has high fluidity at the time of melting, it can be molded into a part having a thin wall or a complicated shape, and has excellent heat resistance and heat and humidity resistance. It is suitable for hot melt molding applications of electronic and electrical parts that are injection molded at low pressure.

Hereinafter, the present invention will be described in detail.
The heat conductive resin composition of the present invention contains a copolyester resin (A) and a heat conductive filler (B), and the copolyester resin (A) contains an aromatic dicarboxylic acid and a dimer acid. It comprises an acid component contained, and a glycol component containing 1,4-butanediol and polybutadiene glycols.

First, the acid component of the copolyester resin (A) will be described. In the present invention, the copolyester resin (A) contains an aromatic dicarboxylic acid and a dimer acid as an acid component.
In the present invention, examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid, phthalic anhydride, naphthalenedicarboxylic acid, etc., and these acids may be used in combination. The ester-forming derivatives of
The aromatic dicarboxylic acid contributes to increasing the melting point of the copolyester resin (A), imparting heat resistance and increasing mechanical strength, and its content is 50 to 90 mol% in the acid component. Preferably there is. When the content of the aromatic dicarboxylic acid is less than 50 mol%, the copolymer polyester resin (A) has a low melting point, is inferior in heat resistance, and tends to be low in mechanical strength. On the other hand, when the content of the aromatic dicarboxylic acid exceeds 90 mol%, the content of the dimer acid is decreased, and the flexibility of the copolymerized polyester resin (A) tends to be poor.

In the present invention, dimer acid is used together with the aromatic dicarboxylic acid as the acid component of the copolyester resin (A). Dimer acid is an unsaturated fatty acid obtained by thermal polymerization of unsaturated fatty acids such as purified vegetable fatty acids obtained from drying oils or semi-drying oils, or saturated fatty acids obtained by partially or completely hydrogenating them. Say. These dimer acids are mainly composed of dimers of unsaturated fatty acids or hydrogenated products thereof, but also include trimers and tetramers. Commercially available "Pripole", "Pliplast" (Croda), "Enpole", "Sobamol" (Cognis), "Unidim" (Arizona Chemical), "Tsunodaim" (Tsukino Food Industries) ) Etc. can be used.
The content of the dimer acid in the copolymerized polyester resin (A) acid component needs to be 10 to 50 mol%, and preferably 20 to 40 mol%. By containing dimer acid as a copolymerization component, the resulting copolymerized polyester resin (A) is excellent in flexibility and also improved in heat and moisture resistance. When the content of the dimer acid is less than 10 mol%, it becomes difficult to impart flexibility to the resulting copolymerized polyester resin (A), and the effect of improving the heat and moisture resistance becomes poor. On the other hand, when the content of the dimer acid exceeds 50 mol%, the melting point of the resulting copolyester resin (A) becomes low, the heat resistance is inferior, and the mechanical strength tends to be low.

  In the present invention, the copolyester resin (A) contains the above aromatic dicarboxylic acid and dimer acid as the acid component, but contains acid components other than these as long as the effects of the present invention are not impaired. May be. Examples of such an acid component include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and eicosanedioic acid.

  The copolymerized polyester resin (A) used in the present invention contains 1,4-butanediol and polybutadiene glycols as a glycol component. The content of 1,4-butanediol in the glycol component needs to be 80 mol% or more, preferably 85 to 98 mol%. By containing 80 mol% or more of 1,4-butanediol as the glycol component, the resulting copolymer polyester resin (A) has a high melting point, excellent heat resistance, and excellent moldability. For example, when 1,2-ethylene glycol is used instead of 1,4-butanediol, the resulting copolymer polyester resin has a low crystallization rate and poor moldability. When diol is used, the copolymer polyester resin obtained has a low melting point and is inferior in heat resistance.

In the present invention, polybutadiene glycols are used together with the 1,4-butanediol as the glycol component of the copolyester resin (A). The content of the polybutadiene glycol in the glycol component needs to be 1 to 20 mol%, and preferably 2 to 15 mol%. By containing polybutadiene glycols in the glycol component, the resulting copolyester resin (A) has excellent heat and moisture resistance and flexibility. When the content of the polybutadiene glycol is less than 1 mol%, it is difficult to obtain the effect of adding the polybutadiene glycol. On the other hand, if the content of polybutadiene glycol exceeds 20 mol%, the resulting copolymerized polyester resin (A) has a low melting point, is inferior in heat resistance, and tends to be low in mechanical strength.
The polybutadiene glycols preferably have an average molecular weight of 350 to 6000, and more preferably 500 to 4500. When the average molecular weight of the polybutadiene glycol exceeds 6000, the compatibility is lowered and it is difficult to copolymerize. On the other hand, when the molecular weight is less than 350, the flexibility of the resulting copolyester resin (A) tends to be lowered.
Examples of polybutadiene glycols include 1,2-polybutadiene glycol, 1,4-polybutadiene glycol, and the like, as well as hydrogenated polybutadiene glycol obtained by hydrogen reduction of these. More specifically, for example, a diol (polybutadiene glycol) obtained by polymerizing butadiene by anionic polymerization and introducing a hydroxyl group or a group having a hydroxyl group at both ends by terminal treatment, obtained by hydrogen reduction of these double bonds. Diol (hydrogenated polybutadiene glycol) and the like.
As the polybutadiene glycols, known products or commercially available products can be used. Specifically, polybutadiene glycol mainly having 1,4-repeat units (for example, “Poly bd R-45HT”, “Poly bd R-15HT” manufactured by Idemitsu Kosan Co., Ltd.), 1,2-repeat units are mainly used. Polybutadiene glycol (for example, “G-1000”, “G-2000”, “G-3000” manufactured by Nippon Soda Co., Ltd.), hydrogenated polybutadiene glycol mainly having 1,2-repeating units (for example, Nippon Soda) "GI-1000", "GI-2000", "GI-3000") manufactured by the company.

  In the present invention, the copolyester resin (A) contains the above 1,4-butanediol and polybutadiene glycols as the glycol component, but other glycols as long as the effects of the present invention are not impaired. You may contain a component. Examples of such glycol components include ethylene glycol, propylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, bisphenol A ethylene oxide adduct and propylene oxide. Examples include adducts, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

The copolyester resin (A) used in the present invention is excellent in heat resistance, but the melting point is preferably 120 to 180 ° C, more preferably 130 to 170 ° C. When the melting point is less than 120 ° C., the heat resistance is poor, and the use is limited. On the other hand, if it exceeds 180 ° C., it is necessary to increase the processing temperature at the time of molding, which is disadvantageous in terms of cost, and at the same time, thermal degradation of the resin increases.
The copolymer polyester resin (A) preferably has a melt viscosity at 200 ° C. of 1 to 300 Pa · s, more preferably 10 to 150 Pa · s. When the melt viscosity is within this range, even when a large amount of the heat conductive filler (B) is blended, a molding process can be performed at a low pressure, which is suitable for hot melt molding applications. When the melt viscosity exceeds 300 Pa · s, the fluidity becomes low and molding at low pressure becomes difficult. Further, when the melting temperature is increased in order to reduce the melt viscosity, the load on the apparatus increases and the thermal deterioration of the copolyester resin (A) becomes remarkable. On the other hand, when the melt viscosity is less than 1 Pa · s, the strength of the copolyester resin (A) is lowered.
Furthermore, the copolyester resin (A) used in the present invention is excellent in flexibility, but as an index indicating flexibility, the Young's modulus at 20 ° C. is preferably 100 MPa or less, more preferably 50 MPa or less. preferable. When the Young's modulus at 20 ° C. exceeds 100 MPa, the copolymer polyester resin (A) tends to be poor in flexibility.

  Next, the manufacturing method of the copolyester resin (A) used for this invention is demonstrated. A copolyester resin (A) can be obtained by polycondensation of the above dicarboxylic acid and glycol components at 230 to 300 ° C. under reduced pressure after an esterification reaction at 150 to 250 ° C. Alternatively, by using a derivative such as dimethyl ester of dicarboxylic acid and a glycol component as described above, a polyester resin (A ) Can be obtained.

In this invention, in order to provide thermal conductivity to a resin composition, a heat conductive filler (B) is mix | blended. As the heat conductive filler (B), either conductive or electrically insulating materials can be used, but those having a heat conductivity of 10 W / (m · K) or more are preferable. The thermal conductivity of the heat conductive filler (B) can be measured, for example, using the sintered product. Specific examples of the thermally conductive filler (B) (representing a representative value of thermal conductivity (unit: W / (m · K)) in parentheses), aluminum oxide (36), magnesium oxide ( 60), zinc oxide (25), magnesium carbonate (15), silicon carbide (160), aluminum nitride (170), boron nitride (50-200), silicon nitride (40), metal silicon (148), carbon (10 To several hundred), graphite (10 to several hundred), talc (10), kaolin (10) and other inorganic fillers, silver (427), copper (398), aluminum (237), titanium (22), nickel (90), tin (68), iron (84), metallic fillers such as stainless steel (15), and the like.
Among these, graphite, boron nitride, aluminum oxide, magnesium carbonate, zinc oxide or talc are particularly preferable, and two or more of these can be used in combination.

As a form of a heat conductive filler (B), granular form or fibrous form is mentioned. When the form of the heat conductive filler (B) is granular, the average particle diameter is preferably 1 to 300 μm, and more preferably 5 to 150 μm. If the average particle size is less than 1 μm, agglomerates are likely to occur due to poor dispersion in the resin composition, and a uniform resin composition cannot be obtained, and mechanical properties tend to deteriorate or thermal conductivity tends to vary. . If the average particle size exceeds 300 μm, it may be difficult to fill the resin composition at a high concentration, or the surface of the resulting molded product may become rough. Moreover, since it exists in the tendency for the melt fluidity of a resin composition to improve when a shape is a spherical shape, it is preferable.
When the form of the heat conductive filler (B) is fibrous, the average fiber diameter is preferably 1 to 30 μm, and more preferably 5 to 20 μm. If the average fiber diameter is less than 1 μm, sufficient thermal conductivity cannot be obtained, and if the average fiber diameter exceeds 30 μm, the workability may be lowered. Moreover, it is preferable that average fiber length is 1-20 mm, and it is more preferable that it is 3-15 mm. When the average fiber length is less than 1 mm, sufficient heat conduction tends not to be obtained when the resin composition is used. As the average fiber length is longer, not only the thermal conductivity of the resin composition is increased, but also the bending strength and the flexural modulus are increased. However, when the average fiber length exceeds 20 mm, the melt fluidity of the resin composition is greatly decreased. This is not preferable in terms of workability.
In the present invention, as the thermally conductive filler (B), flaky graphite having an average particle diameter of 1 to 300 μm, flaky boron nitride having a hexagonal crystal structure having an average particle diameter of 1 to 200 μm, an average particle diameter of 0. 5 to 150 μm aluminum oxide, magnesium carbonate having an average particle size of 0.5 to 150 μm, zinc oxide having an average particle size of 0.5 to 150 μm, and talc having an average particle size of 0.5 to 150 μm are preferable.

  The heat conductive filler (B) used in the present invention may be subjected to a surface treatment with a silane coupling agent, a titanium coupling agent or the like in order to improve adhesion with the copolymerized polyester resin (A). . Examples of the coupling agent include γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyldimethoxymethylsilane, and the like. Epoxysilane coupling agents such as aminosilane coupling agents, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, Examples thereof include titanium coupling agents such as isopropyl tristearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, and tetraisopropyl bis (dioctyl phosphite) titanate. These may be used alone or in combination.

  In the resin composition of the present invention, the volume ratio (A / B) of the copolymerized polyester resin (A) and the thermally conductive filler (B) needs to be 30/70 to 90/10, More preferably, it is 40/60 to 70/20. When the copolymerized polyester resin (A) is less than 30% by volume, the melt fluidity of the resin composition tends to be remarkably lowered, the load at the time of molding becomes too high, and the operability may be lowered. Moreover, when the copolymerized polyester resin (A) exceeds 90% by volume, sufficient thermal conductivity tends to be not obtained.

  In the resin composition of the present invention, polyethylene, polypropylene, polybutadiene, polystyrene, AS resin, ABS resin, poly (acrylic acid), poly (acrylic acid ester), poly (acrylic acid ester), poly (acrylic acid ester), poly (acrylic acid ester), poly (acrylic acid ester), and poly (acrylic acid ester). A resin such as methacrylic acid), poly (methacrylic acid ester), polyethylene terephthalate, polyethylene naphthalate, polycarbonate, and a copolymer thereof may be added.

  In order to further improve various properties such as mechanical strength and heat resistance, a fibrous filler can be blended in the resin composition of the present invention. Specific examples of the fibrous filler include glass fiber, aramid fiber, carbon fiber, metal fiber, silica fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, and kenaf. Natural fibers represented by These fibrous fillers can be used in combination of two or more. In addition, the method of mixing these with a resin composition is not specifically limited.

In the resin composition of the present invention, the pigment, heat stabilizer, antioxidant, weathering agent, flame retardant, plasticizer, lubricant, mold release agent, antistatic agent, filler, A crystal nucleating agent or the like can be added.
Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like.
As the flame retardant, a halogen-based flame retardant, a phosphorus-based flame retardant, and an inorganic flame retardant can be used. However, in consideration of the environment, it is desirable to use a non-halogen flame retardant. Non-halogen flame retardants include phosphorus flame retardants, hydrated metal compounds (aluminum hydroxide, magnesium hydroxide, etc.), nitrogen-containing compounds (melamine-based, guanidine-based), inorganic compounds (borates, Mo compounds, etc.) Is mentioned.
Inorganic fillers include layered silicate, calcium carbonate, zinc carbonate, wollastonite, silica, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, antimony trioxide, zeolite, And hydrotalcite. Examples of the organic filler include naturally occurring polymers such as starch, cellulose fine particles, wood flour, okara, fir shell, bran, and modified products thereof. In addition, the method of mixing these with the heat conductive resin composition of this invention is not specifically limited.

  The heat conductive resin composition of the present invention is a general extruder such as a co-polyester resin (A), a heat conductive filler (B), and various additives as required, such as a single screw extruder. It can be produced by melt-kneading using a twin screw extruder, roll kneader, Brabender or the like. At this time, it is also effective to use a static mixer or a dynamic mixer together. In order to improve the kneading state, it is preferable to use a twin screw extruder. The addition method of each composition is not particularly limited, but in the extruder, it can be added simultaneously or sequentially from a hopper or using a side feeder.

The thermally conductive resin composition of the present invention can be molded into a desired shape using a generally known melt molding method such as injection molding, compression molding, extrusion molding, transfer molding, sheet molding, or the like to obtain a molded body.
Among these, the heat conductive resin composition of the present invention is suitable as a resin for hot melt molding. The hot melt molding referred to in the present invention is a molding technique in which a hot melt adhesive (thermoplastic resin) is injected into a mold at a low pressure of 0.1 to 10 MPa. In conventional plastic molding, injection molding is performed at a high pressure of about 100 MPa on average. Compared to this, hot melt molding is a molding technique performed at a very low pressure. After the resin is melted, it is injected at a low pressure into a mold in which electric and electronic parts are set, and the resin is used as a part. Can be molded without damaging delicate electric / electronic parts.
Thus, the heat conductive resin composition of this invention can be used conveniently also as a sealing material for electrical / electronic components.

  Specific examples of the molded body formed by molding the heat conductive resin composition of the present invention include coils, sealing materials such as semiconductor elements and resistors, connectors, sockets, relay parts, coil bobbins, optical pickups, oscillators, and computers. Electrical and electronic parts such as related parts, VTRs, TVs, irons, air conditioners, stereos, vacuum cleaners, refrigerators, rice cookers, lighting appliances and other household electrical parts, heat dissipation sheets, heat sinks, heat from fans and other electronic parts Heat-dissipating members for escaping to the outside, lamp fixtures, lamp reflectors, lamp fixtures and other lighting fixture parts, compact discs, laser discs (registered trademark), acoustic product parts such as speakers, ferrules for optical cables, mobile phones, fixed phones, facsimiles, Communication equipment parts such as modems, copiers such as separating claws and heater holders, marks Machine-related parts, impellers, fan gears, gears, bearings, motor parts, motor parts and case machine parts, automotive mechanism parts, engine parts, engine room parts, electrical parts, interior parts, etc. automotive parts, microwave cooking pans And cooking utensils such as heat-resistant dishes, aircraft, spacecraft, parts for space equipment, sensor parts and the like.

Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited to only these examples.
In the following production examples, examples and comparative examples, test methods for various physical property values are as follows.
(1) Melting point About copolymer polyester resin obtained by the manufacture example, using Perkin-Elmer diamond DSC, it heated up and cooled down at 10 degree-C / min, and measured at the temperature of the melting peak.
(2) Melt Viscosity Using a flow tester (manufactured by Shimadzu Corporation, model CFT-500), a melt viscosity at a shear rate of 1000 sec ⁻¹ was measured using a nozzle having a nozzle diameter of 1.0 mmφ and a nozzle length of 10 mm.
(3) Copolyester resin composition The copolyester resin obtained in the production example was dissolved in a mixed solvent of deuterated hexafluoroisopropanol and deuterated chloroform in a volume ratio of 1/20. ¹ H-NMR was measured with a 400-type NMR apparatus, and obtained from the integrated intensity of the proton peak of each copolymer component in the obtained chart.
(4) Tensile fracture strain About the heat conductive resin composition obtained by the Example and the comparative example, according to the method as described in ISO standard 527-2, using the injection molding machine "PS20E2ASE" by Nissei Plastic Industry Co., Ltd. Test specimens were prepared by injection molding, and tensile fracture strain was measured.
(5) Charpy impact strength For the thermally conductive resin compositions obtained in Examples and Comparative Examples, an injection molding machine “PS20E2ASE” manufactured by Nissei Plastic Industry Co., Ltd. was used according to the method described in ISO standard 179-1. Then, a notched specimen was produced by injection molding, and the Charpy impact strength was measured.
(6) Moisture and heat resistance Using a constant temperature and humidity chamber (IG400 type manufactured by Yamato Kagaku Co., Ltd.), the tensile test piece obtained in (4) above is stored for 200 hours in an environment of a temperature of 60 ° C. and a humidity of 95% RH, The tensile fracture strain was measured in the same manner as in (4), and the wet heat resistance was evaluated by the strain retention before and after the wet heat treatment. The strain retention rate (%) was calculated as (strain retention rate) = (tensile fracture strain after treatment) / (tensile fracture strain before treatment) × 100.
(7) Thermal conductivity The thermal conductivity λ was calculated by the following equation as the product of the thermal diffusivity α, the density ρ, and the specific heat Cp obtained by the following method.
λ = αρCp
λ: thermal conductivity (W / (m · K))
α: Thermal diffusivity (m ² / sec)
ρ: Density (g / m ³ )
Cp: Specific heat (J / (g · K))
The thermal diffusivity α is obtained by molding the thermally conductive resin compositions obtained in Examples and Comparative Examples into a 30 mmφ disk shape with an injection molding machine, and cutting out to a predetermined size from the obtained molded product. The measurement was performed by the laser flash method using a laser flash method thermal constant measuring device TC-7000 (manufactured by ULVAC-RIKO). The density ρ was measured using an electronic hydrometer ED-120T (manufactured by Mirage Trading Co.). The specific heat Cp was measured using a differential scanning calorimeter DSC-7 (manufactured by Perkin Elmer) under the condition of a heating rate of 10 ° C./min.

The raw materials used in the following examples and comparative examples are shown below.
(1) Copolyester resin / Production Example 1 (A1)
As an acid component, 62 parts by mass of terephthalic acid, 9 parts by mass of isophthalic acid, 76 parts by mass of hydrogenated dimer acid having 36 carbon atoms (Pripol 1009, manufactured by Croder Japan), and 59 parts by mass of 1,4-butanediol as a diol component Part, polybutadiene glycol (hydrogenated polybutadiene glycol mainly having 1,2-repeat units; Nippon Soda Co., Ltd., “GI-1000”, average molecular weight 1500) 65 parts by mass, tetra-n-butyl titanate 2 mass Part was added and heated to 240 ° C. to conduct a transesterification reaction. Next, while gradually increasing the degree of vacuum at a temperature of 240 ° C. for 60 minutes, a high vacuum of 10 to 30 Pa is obtained. Thereafter, a polycondensation reaction is performed for 4 hours. Got. (Melting point 148 ° C., melt viscosity 60 Pa · s, density 1.10 g / cm ³ )

・ Production Examples 2 to 9 (A2 to A5, a1 to a4)
Except having changed the kind and addition amount of terephthalic acid, isophthalic acid, hydrogenated dimer acid, 1,4-butanediol, and 1,2-polybutadiene glycol, it carried out similarly to manufacture example 1, and obtained copolyester resin. . In Production Example 5, as polybutadiene glycol, polybutadiene glycol having mainly 1,2-repeating units (“G-2000”, average molecular weight 2000, manufactured by Nippon Soda Co., Ltd.) is used, and copolymer polyester resin (A5). Manufactured.

  Table 1 shows the composition, melting point, and melt viscosity of the copolyester resins obtained in Production Examples 1-9.

(2) Thermally conductive filler (B)
ALO: Aluminum oxide (manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 10 μm, thermal conductivity 38 W / (m · K), density 3.97 g / cm ³ )
MgCO: Magnesium carbonate (manufactured by Kamishima Chemical Co., Ltd., average particle size 10 μm, thermal conductivity 15 W / (m · K), density 3.05 g / cm ³ )
ZnO: Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., average particle size 10 μm, thermal conductivity 25 W / (m · K), density 5.78 g / cm ³ )
TC: Talc (K-1 manufactured by Nippon Talc Co., Ltd., average particle size 8 μm, thermal conductivity 10 W / (m · K), density 2.7 g / cm ³ )
Gr: scale-like graphite (manufactured by Nippon Graphite Industries Co., Ltd., average particle size 40 μm, thermal conductivity 100 W / (m · K), density 2.25 g / cm ³ )
BN: hexagonal scaly boron nitride (manufactured by Denki Kagaku Kogyo Co., Ltd., thermal conductivity 80 W / (m · K), average particle size 15 μm, density 2.26 g / cm ³ )

Example 1
As a main hopper of a twin screw extruder (manufactured by Toshiba Machine Co., Ltd .: TEM26SS, screw diameter 26 mm), 60 parts by volume of the copolyester resin (A1) obtained in Production Example 1 and a thermally conductive filler (B) 40 parts by volume of aluminum oxide (ALO) was supplied and melt-kneaded at 200 ° C. And after extruding in the shape of a strand and cooling and solidifying, it cut | disconnected to the shape of a pellet, and obtained the resin composition.

Examples 2-16
A resin composition was obtained in the same manner as in Example 1 except that the copolymer polyester resin (A) and the thermally conductive filler (B) were changed to the types and amounts shown in Table 2, respectively.

Comparative Examples 1 and 2
A resin composition was obtained in the same manner as in Example 1 except that the copolymer polyester resin (A) and the heat conductive filler (B) were changed to the types and amounts shown in Table 2 and melt kneaded at 230 ° C. Got.

Comparative Examples 3-6
A resin composition was obtained in the same manner as in Example 1 except that the copolymer polyester resin (A) and the heat conductive filler (B) were changed to the types and amounts shown in Table 2 and melt kneaded at 150 ° C. Got.

Comparative Examples 7-12
A resin composition was obtained in the same manner as in Example 1 except that the copolymerized polyester resin (A) and the thermally conductive filler (B) were changed to the types and amounts shown in Table 2 and melt kneaded at 200 ° C. Got.

  The resin compositions obtained in Examples 1 to 16 and Comparative Examples 1 to 12 were evaluated for melt viscosity, tensile fracture strain, Charpy impact strength, thermal conductivity, and wet heat resistance. The evaluation results are shown in Table 2.

  As is clear from Table 2, the resin compositions obtained in Examples 1 to 16 were compositions satisfying the present invention, so that the tensile fracture strain was high, the flexibility was excellent, and the impact resistance was high. Further, since the copolymer polyester resin (A) containing a predetermined amount of polybutadiene glycol in the glycol component is used, the heat resistance and the heat and moisture resistance are excellent.

On the other hand, since the resin composition obtained in Comparative Examples 1 and 2 had a low content of dimer acid in the acid component of the copolymer polyester resin used, it was inferior in flexibility, impact resistance, and heat and humidity resistance. It was a thing.
The resin compositions obtained in Comparative Examples 3 and 4 had a high content of dimer acid in the acid component of the copolymer polyester resin used, and therefore the melting point could not be measured and the heat resistance was poor. It was.
The resin compositions obtained in Comparative Examples 5 and 6 had a high content of polybutadiene glycols in the glycol component of the copolymer polyester resin used, and therefore had a low melting point and poor heat resistance. .
Since the resin composition obtained in Comparative Examples 7 and 8 did not contain polybutadiene glycols in the glycol component of the copolymerized polyester resin used, the resin composition was inferior in heat and moisture resistance.
The resin compositions obtained in Comparative Examples 9 and 10 had a low thermal conductivity because the amount of the thermal conductive filler (B) was small.
The resin compositions obtained in Comparative Examples 11 and 12 were too high in melt viscosity because the amount of the heat conductive filler (B) was too large to be injection molded.

Example 17
A coil was produced by winding a polyamide-imide resin-coated copper wire around a coil bobbin made of glass-reinforced polybutylene terephthalate. This coil was placed in a mold maintained at 80 ° C., and the resin composition obtained in Example 2 was supplied to a vertical injection molding machine (TNS100R12V), under the conditions of a cylinder temperature of 200 ° C. and an injection pressure of 20 MPa. A coil member in which the entire coil was sealed by injection molding into a mold was produced. Generation of cracks was not observed on the surface of the obtained coil member, and when a cross section was observed after cutting, no generation of voids or cracks was observed.
Next, after the coil member produced in the same manner was heated at 100 ° C. for 1 hour and then cooled at 0 ° C. for 1 hour, a cooling cycle was repeated 100 cycles. Generation | occurrence | production was not seen, but when cut | disconnected and the cross section was observed, generation | occurrence | production of the void and the crack was not seen.

Comparative Example 13
A coil member was produced in the same manner as in Example 17 except that the resin composition was changed to that obtained in Comparative Example 1 and injection molding was performed at an injection pressure of 40 MPa. Cracks were generated on the surface of the obtained coil member.

Comparative Example 14
A coil member was produced in the same manner as in Example 17 except that the resin composition was changed to that obtained in Comparative Example 5 and injection molding was performed at a cylinder temperature of 150 ° C. and an injection pressure of 40 MPa. Generation of cracks was not observed on the surface of the obtained coil member, and when a cross section was observed after cutting, no generation of voids or cracks was observed.
Next, when the coil member produced in the same manner was subjected to 100 cycles of cooling and heating in the same manner as in Example 17, the coil member was deformed after the end of the cycle.

Comparative Example 15
A coil member was produced in the same manner as in Example 17 except that the resin composition was changed to that obtained in Comparative Example 6 and injection molding was performed at a cylinder temperature of 150 ° C. and an injection pressure of 50 MPa. Generation of cracks was not observed on the surface of the obtained coil member, and when a cross section was observed after cutting, no generation of voids or cracks was observed.
Next, when the coil member produced in the same manner was subjected to 100 cycles of cooling and heating in the same manner as in Example 17, the coil member was deformed after the end of the cycle.

Claims (5)

A resin composition containing a copolymerized polyester resin (A) and a thermally conductive filler (B) and having a volume ratio (A / B) of (A) and (B) of 30/70 to 90/10 Is a thing,
(A) contains aromatic dicarboxylic acid and dimer acid as the acid component, and contains 1,4-butanediol and polybutadiene glycol as the glycol component,
The content of dimer acid in the acid component is 10 to 50 mol%,
The content of 1,4-butanediol in the glycol component is 80 mol% or more,
The heat conductive resin composition, wherein the content of polybutadiene glycol in the glycol component is 1 to 20 mol%.   The heat conductive filler (B) is at least one selected from flaky graphite, flaky boron nitride having a hexagonal crystal structure, aluminum oxide, magnesium carbonate, zinc oxide, and talc. Item 2. The heat conductive resin composition according to Item 1.   The molded object formed by shape | molding the heat conductive resin composition of Claim 1 or 2.   The sealing material for electrical / electronic components containing the heat conductive resin composition of Claim 1 or 2. An electrical / electronic component sealed with the sealing material according to claim 4.