JP4259407B2 - Polybutylene terephthalate resin composition for encapsulating materials for electrical and electronic parts - Google Patents

Description

The present invention, electricity is relates to polybutylene terephthalate resin composition utilized in the encapsulant of electronic components

As a polyester-based molding material, a polybutylene terephthalate resin composition (PBT resin composition) mainly containing a polybutylene terephthalate resin (hereinafter referred to as PBT resin) is known. Molded articles using this PBT resin composition are used for electric / electronic parts, automobile parts, etc. as those having excellent heat resistance, chemical resistance, electrical characteristics, mechanical characteristics and the like (see Patent Document 1). ).
JP 2002-30205 A

  However, in recent years, there has been a demand for polyester-based molding materials that are further superior in insulation (tracking resistance and arc resistance). The tracking resistance of conventional PBT resin molding materials is usually about 250V, and several methods have been proposed to improve this tracking resistance, but each has its own disadvantages and sufficient countermeasures have been taken. I can't say.

  For example, in the method of adding a polypropylene resin, when the polypropylene resin is added at 10% or more, the tracking resistance becomes 500 V or more, but the polyester resin PBT resin and PP are incompatible and the bending strength is 70 MPa or less. There is a problem that the strength is greatly reduced.

  In addition, in the method of adding a low molecular weight epoxy resin, when 5% or more of a low molecular weight epoxy resin is added, the tracking resistance becomes 400 V or higher, but the material reacts with the PBT resin inside the cylinder during injection molding. May increase the viscosity and cause molding defects.

  Further, in the method of adding an inorganic substance, when 20% or more of talc is added, the tracking resistance becomes 500 V or more, but the strength decreases as the bending strength of the molded product becomes 70 MPa or less, and the specific gravity also increases. When it becomes heavier than 1.5, the product weight increases.

  On the other hand, in order to cope with increasing waste disposal problems and future depletion of petroleum resources, it is also required to reduce the amount of petroleum resources used by using plant resources as raw materials for polyester-based molding materials. It is becoming.

The present invention has been made in view of the above points, and without sacrificing various properties such as strength and moldability, the insulating properties of the molded product are improved and excellent tracking resistance and arc resistance are achieved. Polybutylene terephthalate resin for encapsulating materials for electrical and electronic parts that can be applied and contributes to measures for waste disposal problems and oil resource depletion problems by reducing the amount of petroleum resources used in raw materials The object is to provide a composition.

The polybutylene terephthalate resin composition for encapsulating materials for electric and electronic parts according to the present invention contains a polybutylene terephthalate resin and a polylactic acid resin, and the content of the polybutylene terephthalate resin is 45 to 45% based on the total amount of the composition. It is 90 mass%, Content of the said polylactic acid resin is 5-50 mass% with respect to the composition whole quantity, It is characterized by the above-mentioned. As a result, while maintaining the moldability during molding and the strength of the molded product in a good state, the insulating properties of the molded product can be improved, and the amount of petroleum resources used in the raw material can be reduced. .

In addition, the polybutylene terephthalate resin composition for encapsulating materials for electric and electronic parts described above contains polyethylene terephthalate resin in a range of 5 to 30% with respect to the total amount of the composition, thereby imparting gloss to the molded product. be able to.

The polybutylene terephthalate resin composition for encapsulating materials for electric and electronic parts can contain polybutylene succinate in a range of 1 to 10 % by mass with respect to the total amount of the composition. The tensile elongation rate of the product can be improved.

Electrical as above reporting, by molding the encapsulating material for polybutylene terephthalate resin composition of the electronic components, as it can be while suppressing the amount of petroleum resources, obtain a high INaru molded products insulating properties is there.

  According to the present invention, while maintaining the moldability during molding and the strength of the molded product in a good state, it is possible to improve the insulation characteristics of the molded product, and the molded product is excellent in tracking resistance and arc resistance. Can be obtained, and the amount of oil resources used in the raw material can be reduced, which can contribute to countermeasures for waste disposal problems and oil resource depletion problems.

  The obtained molded product has good insulation characteristics as described above, and has excellent tracking resistance and arc resistance, so that it is particularly electrically insulating in functional parts such as electric / electronic / automobiles. In this case, since the molded product has better insulation performance than the general PBT resin molded product, the distance between terminals can be shortened. The size can be reduced.

The polybutylene terephthalate resin composition for encapsulating materials for electric and electronic parts of the present invention comprises polybutylene terephthalate resin (hereinafter referred to as PBT resin) and polylactic acid resin as constituent materials.

  The PBT resin is a thermoplastic polyester resin obtained by polycondensation of terephthalic acid and 1,4-butanediol, and is a main component as a resin component in the resin composition. The PBT resin imparts characteristics such as heat resistance, chemical resistance, electrical characteristics, and mechanical characteristics to the molded product. The PBT resin can improve the mechanical strength of the molded product when its average molecular weight increases, but it tends to increase the melt viscosity, so that it maintains a good moldability and has a desired mechanical strength for the molded product. It is preferable to use those having an appropriate average molecular weight so that the number average molecular weight is in the range of 50,000 to 60,000.

  Polylactic acid is obtained by polymerizing lactic acid derived from starch extracted from natural materials such as corn. For example, polylactic acid is directly polymerized from lactic acid and ring-opening polymerization of lactide obtained by dimerizing lactic acid. There is a method to synthesize. In the present invention, by including this polylactic acid in the PBT resin composition, the electrical insulation of the molded product is improved, and a molded product having excellent tracking resistance and arc resistance can be obtained. At the same time, by using polylactic acid, which is a component derived from plant resources, as a raw material for the PBT resin composition, it is possible to suppress the amount of petroleum resources used and contribute to environmental conservation.

  In order to obtain the effect of the present invention, the content of polylactic acid needs to be 5 to 50% by mass with respect to the total amount of the composition. If the content of polylactic acid is less than this range, insulation of the molded product is required. The characteristics cannot be improved sufficiently, and if it exceeds this range, it is difficult to cool and solidify during molding, and the cooling time becomes longer.

  The PBT resin resin composition preferably contains a polyethylene terephthalate resin (PET resin). The PET resin is a thermoplastic polyester resin obtained from terephthalic acid and ethylene glycol. When this PET resin is contained in the composition, gloss can be imparted to the molded product.

When the PET resin is contained, the content is preferably in the range of 5 to 30% by mass with respect to the total amount of the composition. If the content of the PET resin is less than this range, The gloss cannot be improved sufficiently, and if it exceeds this range, the appearance of the molded product may be deteriorated.

  Moreover, it is also preferable that polybutylene succinate (PBS) is further contained in the PBT resin composition. PBS is synthesized, for example, by dehydration polycondensation of succinic acid and butanediol. By containing this PBS, the tensile elongation rate of the molded product can be improved, and the occurrence of breakage such as cracking when a load is applied to the molded product can be suppressed.

  This PBS is preferably contained in a proportion of 1 to 10% by mass with respect to the total amount of the composition, and if the content is less than this range, the tensile elongation of the molded product cannot be sufficiently improved and contained. If the amount exceeds this range, the mechanical strength such as the bending strength of the molded product may be lowered.

  The PBT resin resin composition preferably contains an inorganic filler. Such an inorganic filler can act as a crystal nucleating agent in the composition, increase the crystallization speed of the material, and shorten the cooling time during injection molding. At this time, the content of the inorganic filler is preferably in the range of 0.1 to 40% by mass with respect to the total amount of the composition. If the content is less than this range, the crystallization rate can be sufficiently increased. In addition, if it exceeds this range, the appearance of the molded product may be deteriorated, or the melt viscosity may become too high to maintain good moldability during injection molding.

  As the above-mentioned inorganic filler, appropriate ones such as talc, mica, glass fiber, carbon fiber, etc. are used, but when a fibrous inorganic filler such as glass fiber, carbon fiber, etc. is contained in particular, the molded product High mechanical strength can be imparted.

  It is also preferable to contain a compatibilizing agent. Examples of the compatibilizing agent include a product name “Modiper A4400” manufactured by Nippon Oil & Fat Co., Ltd. In this case, the compatibilizing agent can improve the compatibility of the PBT resin and polylactic acid and increase the strength of the molded product (bending strength). The compatibilizing agent is desirably contained in the range of 1 to 10% by mass relative to the total amount of the composition. If the content is small, the effect of improving the strength is small, and even if the content exceeds 10% by mass, the improvement of the strength is saturated.

Moreover, you may add flame retardants, such as brominated epoxy resin and antimony trioxide, to the said PBT resin composition as needed. For example, when a brominated epoxy resin is added to the PBT resin composition in an amount of 10% by mass or more based on the total amount of the composition, a molded product having a flame retardancy test evaluation of UL94 of V-2 can be obtained. When the resin is added in an amount of 10% by mass or more with respect to the total amount of the composition and the antimony trioxide is added in an amount of 5% by mass or more with respect to the total amount of the composition, a molded product having a flame resistance test evaluation according to UL94 of V-0 is obtained. Therefore, the PBT resin composition can be prepared by blending and mixing predetermined amounts of the above components. For example, after blending a predetermined amount of each of the above components, mixing uniformly with a mixer, blender, etc., heating and kneading with a twin screw extrusion kneader, etc. An inorganic filler is added and further kneaded. Next, kneading and extrusion are performed at a cylinder temperature of about 240 to 260 ° C. to form a string-like strand, which is cooled and solidified, and then cut into a pellet.

  The molded article of the present invention is molded using the PBT resin composition. This molded product is produced by injection molding or the like with an injection molding machine.

  Since the obtained molded product has excellent tracking performance and arc insulation performance, it can be suitably used for functional parts such as electric / electronic / automobiles, particularly for parts requiring electrical insulation. . For example, it can be used for various applications such as switches, relays, bobbins, terminal blocks, metal terminal insert accessory boxes, relay boxes, anti-lock brake system housings, and EPS (electric power steering) housings. In this case, since the molded product has better insulation performance than a general PBT resin molded product, the distance between terminals can be shortened, and the molded product can be downsized.

For each example , reference example and comparative example, the materials shown in Table 1 were dried in advance, mixed with a tumbler for 10 minutes, and then passed through a ruder. The temperature of the ruder was set to 230 ° C. near the die and 240 ° C. near the inlet. Next, the strand coming out of the ruder was immediately cooled in a cooling bath, and then cut into 2 to 4 mm pellets with a cutter.

  The obtained molding material was previously dried in a dehumidifying dryer under conditions of 120 ° C. × 4 h, and then a molded product was obtained by injection molding using a 100-ton injection molding machine. The cylinder temperature at the time of molding was set to 240 ° C. near the head, 200 ° C. near the material inlet, and the mold temperature was 80 ° C.

  The obtained molded article was subjected to the following evaluation test.

(Tracking resistance test)
For the molded products obtained in each of the examples , reference examples and comparative examples, the tracking resistance was measured based on the conditions of IEC112.

(Bending strength measurement)
About the molded article obtained by each Example , the reference example, and the comparative example, bending strength was measured based on the conditions of ASTM D790.

(Tensile elongation measurement)
About the molded article obtained by each Example , the reference example, and the comparative example, the tensile elongation rate was measured based on the conditions of ASTM D638.

(Measurement of mold cooling time)
For each example , reference example, and comparative example, when forming a molded product having dimensions of 130 mm × 12.7 mm × 3 mm, the mold can be removed without deformation when the mold is removed with two protruding pins after cooling the mold. The cooling time was measured.

(Observation of molded product appearance)
About each Example , Reference example, and Comparative example, the obtained molded article was observed visually and evaluated on the following evaluation criteria.

◎… Glossy like a mirror surface ○… Slightly glossy, like a wrinkled surface △… No gloss and uneven flow The results are shown in Table 1.

Claims (2)

  It contains a polybutylene terephthalate resin, a polylactic acid resin, and a polyethylene terephthalate resin, the content of the polybutylene terephthalate resin is 45 to 90% by mass with respect to the total amount of the composition, and the content of the polylactic acid resin is the composition Polybutylene for encapsulating materials for electric and electronic parts, characterized in that it is 5 to 50% by mass with respect to the total amount, and the content of the polyethylene terephthalate resin is in the range of 5 to 30% by mass with respect to the total amount of the composition. A terephthalate resin composition.   It contains a polybutylene terephthalate resin, a polylactic acid resin, and a polybutylene succinate, the content of the polybutylene terephthalate resin is 45 to 90% by mass with respect to the total amount of the composition, and the content of the polylactic acid resin is a composition 5 to 50% by mass with respect to the total amount of the product, and the content of the polybutylene succinate is in the range of 1 to 10% by mass with respect to the total amount of the composition. Polybutylene terephthalate resin composition.