JPH0977964A - Molding material for wire harness connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molding material used for a wire harness connector and giving a housing part excellent in flame retardancy, tracking resistance and toughness. SOLUTION: This molding material is obtained by using a resin composition which contains a polybutylene terephthalate resin and a brominated flame retardant and in which the inorganic compound content is controlled to 1wt.% or less based on the polybutylene terephthalate resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a molding material for a wire harness connector made of a flame-retardant polybutylene terephthalate resin composition and a wire harness connector having a housing portion made of the molding material.

[0002]

2. Description of the Related Art Polybutylene terephthalate resins are
Making use of its excellent properties such as heat resistance, mechanical properties, electrical properties, solvent resistance, moldability, and dimensional stability, molding of various molded products such as electric parts, electronic parts, automobile parts, machine parts, etc. Widely used as a material. In that case, various additives are generally added to the polybutylene terephthalate-based resin in order to impart performance depending on the application.

In order to make a polybutylene terephthalate resin flame-retardant, it is known that the compounding of an organic halogen flame retardant and an inorganic flame retardant auxiliary is effective (JP-A-49-14563). , JP-A-50-86550, JP-A-51-73555, etc.). In that case,
Generally, a bromine-based flame retardant is used as the organic halogen-based flame retardant, and an antimony compound-based flame retardant aid (particularly antimony trioxide) is used as the inorganic flame-retardant aid. Regarding a flame-retardant polybutylene terephthalate-based resin composition containing such an organic halogen-based flame retardant and an antimony compound-based flame retardant auxiliary, in order to improve tracking resistance of a molded article, further kaolin, talc, metal It has been proposed to include an inorganic filler such as a salt (Japanese Patent Laid-Open Nos. 51-44159 and 51-12714).
9 and JP-A-52-58752).

[0004]

The wire harness connector is used as an automobile part or the like, but as a molding material for the housing part thereof, it is excellent in dimensional stability and has sufficient toughness. Polybutylene terephthalate resins are often used. In this application, in order to enhance the safety against fire and the like, it is desired that not only the flame retardancy but also the tracking resistance be high in the sense of reducing the ignition factor. However, according to a study by the present inventors, a flame-retardant polybutylene terephthalate-based resin composition containing an organic halogen-based flame retardant and an antimony compound-based flame retardant auxiliary agent or further containing an inorganic filler was used. When the wire harness connector is molded, the wire harness connector can be sufficiently satisfied with respect to flame retardancy, but the tracking resistance is not so high, or the toughness is insufficient and cracks or chips are likely to occur. , It was found that there is still room for improvement in terms of overall performance.

The object of the present invention is to solve the above-mentioned problems and to provide a molding material which provides a wire harness connector excellent in flame retardancy, tracking resistance and toughness in total performance, and in the above-mentioned comprehensive performance. An object is to provide a wire harness connector having a housing part.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and have found that it contains a polybutylene terephthalate resin and a brominated flame retardant, and contains an inorganic flame retardant auxiliary agent. A resin composition having a content of 1% by weight or less with respect to a polybutylene terephthalate-based resin has comprehensively excellent flame retardancy, tracking resistance and toughness, and a wire harness connector made of the composition. In the above, it was found that such excellent performance is effectively exhibited, and as a result of further studies based on these findings, the present invention has been completed.

The present invention is, firstly, a resin composition containing a polybutylene terephthalate resin and a bromine flame retardant, and the content of an inorganic compound is 1% by weight or less based on the polybutylene terephthalate resin. It is a molding material for a wire harness connector, which is made of a material.
Secondly, the present invention is a wire harness connector characterized by having a housing portion made of the resin composition.

The polybutylene terephthalate resin (hereinafter sometimes referred to as "PBT resin") in the present invention includes at least 7 of the acid components constituting the PBT resin.
0 mol% consists of terephthalic acid or its ester-forming derivative (dialkyl ester, diaryl ester of terephthalic acid, etc.) and at least 7 parts of the diol component
A polyester resin in which 0 mol% is composed of 1,4-butanediol is preferable. In this case, other copolymerized acid components and / or other copolymerized diol components may be used within the range of 30 mol% or less with respect to the acid component and the diol component.

Examples of the copolymeric acid component include aromatic dicarboxylic acids such as isophthalic acid, diphenyldicarboxylic acid and naphthalene-1,4-dicarboxylic acid; adipic acid, sebacic acid, azelaic acid, succinic acid, oxalic acid and the like. And aliphatic carboxylic acids such as β-oxyethoxybenzoic acid, p-oxybenzoic acid and the like; or ester-forming derivatives thereof, and the like. Alternatively, two or more kinds may be used.

Further, examples of the copolymerized diol component include:
Ethylene glycol, propylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl-1,8-
C2-C10 aliphatic diols such as octane diol and decamethylene diol; alicyclic diols such as cyclohexane diol; aromatic diols such as bisphenol A and bisphenol S; polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol And the like. These copolymer diol components may be used alone or in combination of two or more.

The method for producing the PBT resin is not particularly limited. For example, the acid component mainly composed of terephthalic acid or its ester-forming derivative and the diol component mainly composed of 1,4-butanediol described above are used. Any of the heretofore known methods for producing an aromatic polyester, which is a method for producing by an ester exchange reaction or a direct esterification reaction, can be used.

In the present invention, as the PBT resin, an intrinsic viscosity of 0.7-1.1.0 when measured at 30 ° C. using a phenol / tetrachloroethane (1: 1 weight ratio) mixed solvent.
It is preferable to use one in the range of 3 dl / g,
It is more preferable to use one in the range of 0.8 to 1.1 dl / g. From the viewpoint of high toughness of the obtained wire harness connector, the above intrinsic viscosity is preferably 0.7 dl / g or more, and more preferably 0.8 dl / g or more. In addition, since the melt viscosity does not become too high and the moldability (particularly the injection moldability) of the wire harness connector is improved, the intrinsic viscosity is preferably 1.3 dl / g or less, 1.1dl
/ G or less is more preferable.

The resin composition of the present invention contains a brominated flame retardant. As the bromine-based flame retardant, it is possible to use both a low molecular weight organic compound and a high molecular weight organic compound having a bromine atom in the molecule known to have a flame retardancy imparting effect. Specific examples of the brominated flame retardant include brominated polycarbonate resin (for example, tetrabromobisphenol A carbonate oligomer), brominated acrylic resin, brominated epoxy resin, brominated phenoxy resin, brominated polystyrene, brominated polyphenylene ether ( For example, polydibromophenylene oxide)
High molecular weight organic compounds such as decabromodiphenyl ether, hexabromophenol, tetrabromobisphenol A, epoxidized tetrabromobisphenol A, tetrabromobisphenol A bis (2,3-dibromopropyl ether), tetrabromobisphenol A bis (Allyl ether), brominated bisphenol A such as 2-hydroxyethyl ether of tetrabromobisphenol A, hexabromobenzene, tetrabromophthalic anhydride, tribromophenol, bis (tribromophenoxy) ethane, bis (pentabromophenoxy) Ethane, ethylene bis tetrabromophthalimide,
Examples thereof include low molecular weight organic compounds such as brominated styrene, tetrabromobisphenol S, and bis (2,3-dibromopropyl ether) of tetrabromobisphenol S. These brominated flame retardants may be used alone or in combination of two or more. Among the above-mentioned brominated flame retardants, high molecular weight organic compounds such as brominated polycarbonate resin, brominated phenoxy resin, brominated polystyrene, brominated acrylic resin are preferable from the viewpoint of flame retardant effect and safety.

The content of the brominated flame retardant is preferably 5 to 30% by weight based on the PBT resin, and 10 to 2 is preferable.
It is more preferably 5% by weight. The content of the brominated flame retardant is P in that the flame retardancy of the PBT resin composition and the wire harness connector obtained therefrom is good.
It is preferably 5% by weight or more based on the BT resin,
It is more preferably 10% by weight or more. On the other hand, PBT
The content of the bromine-based flame retardant is 30 relative to that of the PBT-based resin in that the mechanical properties (particularly toughness) of the resin-based resin composition and the wire harness connector obtained therefrom are improved.
It is preferably not more than 25% by weight, more preferably not more than 25% by weight.

In the present invention, it is important that the content of the inorganic compound in the resin composition is limited to 1% by weight or less based on the PBT resin. Inorganic compounds to be considered here include inorganic flame retardant aids, inorganic fillers and the like. Examples of the inorganic flame retardant aids include antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, tin dioxide, aluminum hydroxide, zirconium oxide, molybdenum oxide and the like. Examples of the inorganic filler include metal fibers such as glass fiber, carbon fiber, aluminum fiber, stainless fiber, brass fiber; inorganic fibers such as silicon nitride whiskers, aluminum silicate whiskers, magnesium silicate whiskers; glass flakes. Inorganic particles such as mica, talc, kaolin, wollastonite, calcium carbonate and potassium titanate can be used. If the content of the inorganic compound exceeds 1% by weight, the mechanical properties (particularly toughness) of the obtained wire harness connector will be insufficient, and in some cases, the tracking resistance will also be insufficient. In a flame-retardant PBT-based resin composition using a bromine-based flame-retardant, an inorganic flame-retardant aid is usually blended in a proportion of more than 1% by weight with respect to the PBT-based resin in order to enhance flame retardancy. However, in that case, the resulting wire harness connector has insufficient tracking resistance and mechanical properties (particularly toughness). In order to improve the tracking resistance of a flame-retardant PBT resin composition containing such a bromine-based flame retardant and an inorganic flame-retardant aid, an inorganic filler such as kaolin, talc, or metal salt is further added. When the agent is blended, the mechanical properties (particularly toughness) of the obtained wire harness connector are further deteriorated. In view of the mechanical properties (particularly toughness) and tracking resistance of the obtained wire harness connector being particularly excellent, the content of the inorganic compound in the resin composition is 0.
It is more preferably 1% by weight or less.

In the present invention, if necessary, the resin composition may contain various conventionally known thermoplastic resins and thermoplastic elastomers. Such examples include polystyrene resin, polycarbonate resin, acrylonitrile butadiene styrene resin, acrylonitrile
Thermoplastic resin such as styrene resin; polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polyisoprene, polychloroprene,
Examples thereof include thermoplastic elastomers such as an isobutylene / isoprene copolymer, an ethylene / propylene copolymer, and polyurethane, and these can be used alone or in combination of two or more kinds. Therefore, in the resin composition of the present invention, the content of the inorganic compound is PBT.
If the amount is 1% by weight or less with respect to the system resin, JP-A-7-17
As described in Japanese Patent No. 3269, having a block of an aromatic vinyl compound polymer and a block of a conjugated diene compound polymer hydrogenated product or isobutylene polymer in the molecular chain, and having a hydroxyl group at the end of the molecular chain. A PBT-based resin composition obtained by performing a synthetic reaction of a PBT-based resin in the presence of a block copolymer having a bromine-based flame retardant may be added. When such a resin composition is used, it is possible to further improve the impact resistance of the obtained wire harness connector.

In the present invention, if necessary, various conventionally known additives to the resin composition, such as organic fillers (aramid fiber, powdery epoxy compound, etc.), ultraviolet absorbers, lubricants, release agents, etc. , An antistatic agent, an antioxidant, a crystal nucleating agent, a coloring agent (dye, pigment, etc.), a plasticizer, a heat stabilizer and the like may be contained.

The method for producing the molding material for a wire harness connector of the present invention is not particularly limited, and a method according to a known method conventionally used for producing a PBT resin composition can be adopted. An example of the manufacturing method is P
BT resin, brominated flame retardant and, if necessary, other compounding agents (resin, elastomer, filler, additives, etc.) are uniformly mixed in advance using a mixer such as a tumbler or a Henschel mixer, 2 to feed into a twin-screw or twin-screw extruder
A method of obtaining pellets for a molding material by melt-kneading at 30 to 280 ° C., extruding, and then cutting into a suitable size can be mentioned.

The shape and structure of the wire harness connector of the present invention are not particularly limited and may be the same as usual ones. For example, a housing part molded from the above molding material and an electrical component made of metal. It is possible to have a structure composed of a male mold composed of contact terminal parts and a female mold composed of a housing part molded from the molding material and an electric contact terminal part made of metal. The method of manufacturing the housing portion of the wire harness connector of the present invention is not particularly limited, and a method according to a known method that has been conventionally used for manufacturing a housing portion of the same type from PBT resin can be adopted. As an example of the manufacturing method, there is a method of obtaining a housing part having a desired shape and size by injection molding using pellets for molding material.

[0020]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto.

In the following examples and comparative examples, the tensile strength / elongation, the Izod impact value, the oxygen index and the tracking resistance of the molding material for wire harness connector, and the falling ball impact and difficulty of the wire harness connector molded article were measured. The flammability was measured as follows.

[Preparation of Test Pieces] Using the pellets of the PBT resin composition of each Example or Comparative Example as a molding material, an 80-ton injection molding machine manufactured by Toshiba Machine Co., Ltd. was used, and a cylinder temperature was 255 ° C. Then, injection molding was performed at a mold temperature of 50 ° C., and then cutting processing was performed to fabricate test pieces having the following dimensions and shapes. For tensile strength / elongation measurement: JIS No. 1 dumbbell (3mm thickness) Izod impact value (with notch) measurement: 63.5mm
Flat plate of x12.7 mm x 3.2 mm For oxygen index measurement: 125 mm x 6 mm x 3.2 mm (JIS K7210 A-1) bar Tracking resistance evaluation: 25 mm x 40 mm x 3 mm
Slab of

[Measurement of Tensile Strength and Tensile Elongation] Using the JIS No. 1 dumbbell (thickness of 3 mm) test piece prepared by the above method, the tensile strength and the tensile elongation were measured according to JIS K7113.

[Measurement of Izod Impact Value] Using the notched test piece produced by the above method, ASTM D25
The Izod impact value was measured according to 6.

[Measurement of Oxygen Index] The oxygen index was measured using the test piece prepared by the above method in accordance with JIS K7201 (combustion test method for polymer materials by oxygen index method).

[Evaluation of Tracking Resistance] Using the test piece prepared by the above method, the tracking resistance was evaluated according to the IEC method. Specifically, the distance between platinum electrodes is 4m
It was set to m, and the electrolytic solution (0.1% ammonium chloride aqueous solution) was added dropwise for evaluation.

[Production of Wire Harness Connector] Using the pellets of the PBT resin composition of each Example or Comparative Example as a molding material, and using a 40-ton injection molding machine manufactured by Nissei Plastic Industry Co., Ltd., a cylinder temperature was measured. The housing part (male and female) of the wire harness connector having the structure of FIG. 1 is manufactured under the conditions of 255 ° C. and mold temperature of 50 ° C.
Using this, falling ball impact and flame retardancy were evaluated as follows.

[Evaluation of Drop Ball Impact of Connector] Using the male mold of the housing part of the connector produced by the above method as a sample for evaluation, 50% breaking energy by free fall of a steel ball (weight: 100 g to 1000 g) was measured. , JIS K7
Evaluation was carried out according to 211.

[Evaluation of Flame Retardancy of Connector] Whether a male mold of the housing portion of the connector manufactured by the above method is used as an evaluation sample and ignited in air to continue combustion for 3 minutes or more. Somehow the flame retardancy was evaluated.

In the following Examples and Comparative Examples, "parts" means "parts by weight" unless otherwise specified.

Example 1 Dimethyl terephthalate 100
Parts, 60 parts of 1,4-butanediol and 0.04 parts of tetraisopropyl titanate are charged into a reaction tank, and the transesterification reaction is performed by heating while gradually raising the temperature from 145 ° C. to 230 ° C. under normal pressure, and methanol is added. When 26 parts were distilled, the transesterification reaction was stopped. Here, the system was transferred to a reduced pressure, and the polycondensation reaction was performed for 90 minutes under reduced pressure (absolute pressure: 0.3 mmHg) with the resin temperature at 240 ° C. After the reaction, the reaction tank was pressurized with nitrogen gas, the PBT resin generated from the bottom of the reaction tank was extruded out of the tank, taken out, and cut into chips. The intrinsic viscosity [η] of the obtained PBT resin was 0.95 dl / g.

100 parts of the PBT resin obtained above and a brominated polycarbonate resin (“BC-
58 ") 15 parts are mixed, and this is supplied to a twin-screw extruder (TEX44C manufactured by Japan Steel Works), and the cylinder temperature is 240 ° C.
Was melt-kneaded and extruded from a die into a strand having a diameter of 2.5 mm, cooled with water, and then cut to produce pellets of a PBT resin composition having a length of about 3 mm. Using this resin composition, a test piece was prepared by the method described above, and its tensile strength / elongation, Izod impact value, oxygen index and tracking resistance were measured. Further, the resin composition was used to prepare a housing part of the wire harness connector by the method described above, and the falling ball impact and flame retardancy were evaluated. Table 1 shows the results.

Example 2 As a brominated flame retardant, brominated phenoxy resin (“YPB-43C” manufactured by Tohto Kasei) was used instead of brominated polycarbonate resin, and PBT resin 10 was used.
PBT-based resin composition pellets were produced in the same manner as in Example 1 except that 15 parts per 0 part were used, and the tensile strength / elongation of the test piece was measured by the above-mentioned method using the pellets. The Izod impact value, oxygen index and tracking resistance were evaluated. Furthermore, the housing part of the wire harness connector was produced by the above-mentioned method, and the falling ball impact and flame retardancy were evaluated. Table 1 shows the results.

Example 3 PBT resin composition pellets were produced in the same manner as in Example 2 except that the amount of the brominated phenoxy resin used was changed from 15 parts to 25 parts. The tensile strength / elongation, Izod impact value, oxygen index and tracking resistance of the test pieces were evaluated by the above-mentioned methods. Furthermore, the housing part of the wire harness connector was produced by the above-mentioned method, and the falling ball impact and flame retardancy were evaluated. Table 1 shows the results.

Example 4 PBT-based resin composition pellets were produced in the same manner as in Example 2 except that the amount of the brominated phenoxy resin used was changed from 15 parts to 10 parts. The tensile strength / elongation, Izod impact value, oxygen index and tracking resistance of the test pieces were evaluated by the above-mentioned methods. Furthermore, the housing part of the wire harness connector was produced by the above-mentioned method, and the falling ball impact and flame retardancy were evaluated. Table 1 shows the results.

Example 5 In addition to the compounding composition of Example 2, antimony trioxide (“Patox-L” manufactured by Nippon Seimitsu Co., Ltd.) was added and compounded at a ratio of 0.5 part to 100 parts of PBT resin. PBT-based resin composition pellets were produced in the same manner as in Example 2 except for the above, and using the pellets, the tensile strength / elongation, Izod impact value, oxygen index and tracking resistance of the test piece were measured by the methods described above. Was evaluated.
Furthermore, the housing part of the wire harness connector was produced by the above-mentioned method, and the falling ball impact and flame retardancy were evaluated. Table 1 shows the results.

Comparative Example 1 PBT-based resin composition pellets were produced in the same manner as in Example 5 except that the content of antimony trioxide was changed from 0.5 parts to 2 parts, and the pellets were used. The tensile strength / elongation, Izod impact value, oxygen index and tracking resistance of the test pieces were evaluated by the above-mentioned methods. Furthermore, the housing part of the wire harness connector was produced by the above-mentioned method, and the falling ball impact and flame retardancy were evaluated. Table 1 shows the results.

Comparative Example 2 PBT-based resin composition pellets were produced in the same manner as in Example 5 except that the content of antimony trioxide was changed from 0.5 parts to 5 parts. The tensile strength / elongation, Izod impact value, oxygen index and tracking resistance of the test pieces were evaluated by the above-mentioned methods. Furthermore, the housing part of the wire harness connector was produced by the above-mentioned method, and the falling ball impact and flame retardancy were evaluated. Table 1 shows the results.

[0039]

[Table 1]

In Table 1 above, "○" in the flame-retardant column means "combustion did not continue in air for 3 minutes or more", and "x" means "combustion in air continued for 3 minutes or more". "I did it."

From the results in Table 1 above, as in Comparative Examples 1 and 2, PBT containing a PBT resin and a brominated flame retardant was used.
When the resin composition further contains an inorganic compound (antimony trioxide) in a proportion of more than 1% by weight with respect to the PBT resin, excellent flame retardancy is exhibited in the wire harness connector, but tracking resistance is improved. It is understood that the toughness represented by tensile elongation and impact resistance (Izod impact value and falling ball impact) is low in addition to low toughness. On the other hand, as in Examples 1 to 4, when the PBT resin composition containing the PBT resin and the brominated flame retardant does not substantially contain the inorganic compound, the flame retardancy in the wire harness connector is reduced. It can be seen that the tracking resistance and the above-mentioned toughness are high while maintaining a good level. Also,
As in Example 5, even if the PBT resin composition containing the PBT resin and the brominated flame retardant further contains an inorganic compound, when the content is 1% by weight or less based on the PBT resin. Is compared with the case where it is not substantially contained,
It can be seen that although the tensile elongation value when evaluated by the test piece is slightly lowered, the wire harness connector exhibits good performance with substantially no difference.

[0042]

Since the PBT resin composition constituting the molding material for a wire harness connector of the present invention is excellent in flame retardancy, tracking resistance and toughness, a wire harness connector having a housing portion molded from the molding material. , Such excellent performance is well-balanced and effective.

[Brief description of drawings]

FIG. 1 (A) is a perspective view showing a female mold of a housing portion of a wire harness connector manufactured in Examples and Comparative Examples. FIG. 1B is a perspective view showing a male mold of the housing portion of the wire harness connector manufactured in the examples and the comparative examples.

Claims (2)

[Claims] 1. A polybutylene terephthalate resin and a bromine flame retardant are contained, and the content of an inorganic compound is 1% by weight based on the polybutylene terephthalate resin.
A molding material for a wire harness connector, comprising the following resin composition. 2. A polybutylene terephthalate resin and a bromine flame retardant are contained, and the content of the inorganic compound is 1% by weight based on the polybutylene terephthalate resin.
A wire harness connector having a housing part made of the following resin composition.