JP2021024879A - Flame-retardant polybutylene terephthalate resin composition - Google Patents

Abstract

To suppress the mixing of foreign matters into a molded article of a flame-retardant polybutylene terephthalate resin composition containing a halogenated epoxy flame retardant as a flame retardant, and to improve the low-warpage properties of the resin composition.SOLUTION: A flame-retardant polybutylene terephthalate resin composition contains a specific dimensional-accuracy improver and contains a halogenated epoxy-based flame retardant as a flame retardant, wherein the flame retardant has an organic-solvent content of a certain value or less, and the total epoxy group content in the whole flame-retardant polybutylene terephthalate resin composition is a certain value or less.SELECTED DRAWING: None

Description

The present invention relates to a flame-retardant polybutylene terephthalate resin composition and a molded product thereof.

Polybutylene terephthalate resin (PBT resin) is excellent in various properties such as mechanical properties, electrical properties, and heat resistance, and is therefore widely used as an engineering plastic in various applications such as automobile parts and electrical / electronic device parts. Of these, in the applications of electrical and electronic equipment parts, flame retardancy is required for the materials used in order to prevent ignition due to tracking, etc., and automobile parts are also required to be flame-retardant due to recent hybridization and electrification. Since various electric and electronic parts are installed, the demand for flame-retardant materials is expanding. Since polybutylene terephthalate resin is insufficient in flame retardancy by itself, it is used as a flame retardant resin composition to which a flame retardant is added.

As a kind of flame retardant added to such polybutylene terephthalate resin, there is a halogenated epoxy flame retardant, and Patent Document 1 introduces a method for producing a brominated epoxy compound flame retardant. This production method uses diglycidyl ether for aromatic nuclei-containing alcohols, di- or polyglycidyl ether for polyhydric phenols, diglycidyl ester for aromatic dibasic acids, monoglycidyl ether for alkylphenols, and monoglycidyl for hydroxybenzoic acid. An aromatic epoxy compound such as an ether ester, a (β-methyl) epichlorohydrin addition product of p-aminophenol, or a polyglycidylamine based on an aromatic di- or polyamines, or a precursor thereof. The chlorhydrin compound is brominated by adding bromine, and the obtained brominated bromhydrin compound or brominated chlorhydrin compound is ring-closed epoxy via hydrogen deodorized or hydrogen chloride using an alkali metal hydroxide. It is characterized by that.

Further, Patent Document 2 introduces a brominated epoxy compound-based flame retardant for engineering thermoplastics. The molecular weight of this flame retardant is 7,000 to 50,000 daltons, and the epoxy equivalent is preferably over 10,000 g / eq.

Furthermore, it is known that brominated epoxy compound flame retardants can thicken by their own reaction, and the thickening during melt kneading produces deposits on the screw, and the carbides are mixed into the molded product. In order to suppress the generation of black foreign matter (BS: Black Spec) due to this, the range of molecular weight and epoxy equivalent has been adjusted. For example, Patent Document 3 introduces that the generation of black foreign matter (carbide) in a molded product of a polybutylene terephthalate resin composition can be suppressed by using an epoxy compound having an epoxy equivalent of 600 to 1500 g / eq.

By the way, since polybutylene terephthalate resin is a crystalline thermoplastic resin, shrinkage due to crystallization after molding and warpage deformation due to its anisotropy are likely to occur. Here, if the above-mentioned foreign matter is mixed in, the effect of the nucleating agent in crystallization is brought about, and deformation due to unexpected shrinkage may occur. Therefore, in the part where dimensional accuracy is required, such foreign matter is suppressed. Is required.

Tokukousho 60-016952 Patent No. 5143419 Patent No. 6100983

An object of the present invention is to suppress the mixing of foreign substances into a molded product and reduce the warpage of the molded product in a polybutylene terephthalate resin composition using a halogenated epoxy flame retardant as the flame retardant.

The present inventor uses a halogenated epoxy-based flame retardant as a flame retardant in the process of research subject to the above, and in a flame-retardant polybutylene terephthalate resin composition containing a specific dimensional accuracy improving agent, the halogenated epoxy. The above problems can be solved by keeping the content of the organic solvent in the flame retardant below a certain amount and the total content of epoxy groups in the entire flame-retardant polybutylene terephthalate resin composition below a certain amount. We have found and completed the present invention.

That is, the present invention relates to the following (1) to (6).
(1) A halogenated epoxy-based difficulty in which the content of an organic solvent selected from the group consisting of (B) toluene, methyl isobutyl ketone, methyl ethyl ketone, and acetone is 50 ppm or less with respect to 100 parts by mass of (A) polybutylene terephthalate resin. A (C) dimensional accuracy improving agent consisting of a flame retardant, (C-1) 0 to 100 parts by mass of an epoxy resin for improving dimensional accuracy, and / or (C-2) a filler for improving dimensional accuracy 0 to 100 parts by mass. A flame-retardant polybutylene terephthalate resin composition containing 10 to 200 parts by mass in total of (C-1) and (C-2), wherein the total content of epoxy groups in the entire composition is 0.0155 mol. A flame-retardant polybutylene terephthalate resin composition, which is characterized by being / kg or less.
(2) The flame-retardant polybutylene terephthalate resin composition according to (1), wherein the epoxy equivalent of the halogenated epoxy flame retardant is 30,000 g / eq or more.
(3) The flame-retardant polybutylene according to (1) or (2), wherein the content of the halogenated epoxy flame retardant is 3 to 50 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin. Terephthalate resin composition.
(4) The flame-retardant polybutylene terephthalate resin composition according to any one of (1) to (3), wherein the halogenated epoxy flame retardant is a brominated epoxy flame retardant.
(5) The flame-retardant polybutylene terephthalate resin according to any one of (1) to (4), which further contains a flame-retardant aid selected from the group consisting of antimony pentoxide, antimony trioxide, and sodium antimonate. Composition.
(6) A molded product obtained by injection molding the flame-retardant polybutylene terephthalate resin composition according to any one of (1) to (5).

According to the present invention, in a polybutylene terephthalate resin composition using a halogenated epoxy-based flame retardant as a flame retardant, the content of the organic solvent in the flame retardant is set to a certain amount or less, and the flame-retardant polybutylene terephthalate resin composition. By setting the total content of epoxy groups in the entire product to a certain amount or less, it is possible to suppress the mixing of foreign substances into the molded product using the flame-retardant polybutylene terephthalate resin composition, and the molded product Warpage can be reduced.

Hereinafter, one embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be carried out with appropriate modifications as long as the effects of the present invention are not impaired.

[Flame-retardant polybutylene terephthalate resin composition]
Hereinafter, details of each component of the flame-retardant polybutylene terephthalate resin composition of the present embodiment will be described with reference to examples.

((A) Polybutylene terephthalate resin)
The polybutylene terephthalate resin (PBT resin) contains a dicarboxylic acid component containing at least terephthalic acid or an ester-forming derivative thereof (C _1-6 alkyl ester, acid halide, etc.) and an alkylene having at least 4 carbon atoms. It is a polybutylene terephthalate resin obtained by polycondensing with a glycol component containing glycol (1,4-butanediol) or an ester-forming derivative thereof (acetylated product, etc.). In the present embodiment, the polybutylene terephthalate resin (A) is not limited to the homopolybutylene terephthalate resin, and may be a copolymer containing 60 mol% or more of butylene terephthalate units.

The amount of the terminal carboxyl group of the polybutylene terephthalate resin (A) is not particularly limited as long as the object of the present invention is not impaired, but is preferably 30 meq / kg or less, and more preferably 25 meq / kg or less.

The intrinsic viscosity of the polybutylene terephthalate resin (A) is not particularly limited as long as it does not impair the object of the present invention, but is preferably 0.60 dL / g or more and 1.2 dL / g or less, and 0.65 dL / g or more and 0. More preferably, it is 9.9 dL / g or less. When a polybutylene terephthalate resin having an intrinsic viscosity in such a range is used, the obtained polybutylene terephthalate resin composition is particularly excellent in moldability. It is also possible to adjust the intrinsic viscosity by blending polybutylene terephthalate resins having different intrinsic viscosities. For example, a polybutylene terephthalate resin having an intrinsic viscosity of 0.9 dL / g can be prepared by blending a polybutylene terephthalate resin having an intrinsic viscosity of 1.0 dL / g and a polybutylene terephthalate resin having an intrinsic viscosity of 0.7 dL / g. Can be done. The intrinsic viscosity of the polybutylene terephthalate resin can be measured, for example, in o-chlorophenol under the condition of a temperature of 35 ° C.

When an aromatic dicarboxylic acid other than terephthalic acid or an ester-forming derivative thereof is used as a comonomer component in the preparation of the polybutylene terephthalate resin (A), for example, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4, _{C 8-14} aromatic dicarboxylic acid such as 4'-dicarboxydiphenyl ether _{; C 4-16} alcandicarboxylic acid such as succinic acid, adipic acid, azelaic acid, sebacic _{acid; C 5-10} such as cyclohexanedicarboxylic acid Cycloalkandicarboxylic acids; ester-forming derivatives of these dicarboxylic acid components (C _1-6 alkyl ester derivatives, acid halides, etc.) can be used. These dicarboxylic acid components can be used alone or in combination of two or more.

Among these dicarboxylic acid components, C _{8-12 aromatic dicarboxylic acids such as isophthalic acid and C 6-12} alkane dicarboxylic acids such as adipic acid, azelaic acid and sebacic acid are more preferable.

When a glycol component other than 1,4-butanediol is used as the comonomer component in the preparation of the polybutylene terephthalate resin (A), for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol , Neopentyl glycol, C _2-10 alkylene glycol such as 1,3-octanediol; polyoxyalkylene glycol such as diethylene glycol, triethylene glycol, dipropylene glycol; alicyclic type such as cyclohexanedimethanol, hydride bisphenol A, etc. _{Diols; aromatic diols such as bisphenol A, 4,4'-dihydroxybiphenyl; C 2-4} alkylene oxides of bisphenol A such as ethylene oxide 2 mol adduct of bisphenol A and propylene oxide 3 mol adduct of bisphenol A. Additives; or ester-forming derivatives of these glycols (acetylates, etc.) can be used. These glycol components can be used alone or in combination of two or more.

_{Among these glycol components, C 2-6} alkylene glycols such as ethylene glycol and trimethylene glycol, polyoxyalkylene glycols such as diethylene glycol, and alicyclic diols such as cyclohexanedimethanol are more preferable.

Examples of the comonomer component that can be used in addition to the dicarboxylic acid component and the glycol component include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4-carboxy-4'-hydroxybiphenyl and the like. Aromatic hydroxycarboxylic acids; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; C _3-12 lactones such as propiolactone, butyrolactone, valerolactone, caprolactone (ε-caprolactone, etc.); esters of these comonomer components Examples thereof include formable derivatives (C _1-6 alkyl ester derivatives, acid halides, acetylates, etc.).

The content of the polybutylene terephthalate resin (A) is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and 30 to 70% by mass, based on the total mass of the resin composition. Is even more preferable.

((B) Halogenated epoxy flame retardant)
The epoxy compound used in the halogenated epoxy flame retardant of the present invention contains one or more epoxy groups in one molecule. As the epoxy compound, it is preferable to use an aromatic epoxy compound from the viewpoint of enhancing thermal stability and hydrolysis resistance. Examples of aromatic epoxy compounds include biphenyl type epoxy compounds, bisphenol A type epoxy compounds, phenol novolac type epoxy compounds, and cresol novolac type epoxy compounds. Further, as the epoxy compound, it is also possible to use any combination of two or more kinds of compounds.

The epoxy equivalent of the above epoxy compound is preferably 30,000 g / equivalent (g / eq) or more, more preferably 32,000 g / eq or more, and even more preferably 34,000 g / eq or more. , 36,000 g / eq or more is even more preferable, and 36,500 g / eq or more is particularly preferable. By setting the epoxy equivalent in this range, the appearance of the molded product obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be improved, and the screw of the extruder or molding machine during molding can be improved. It is possible to suppress the generation of deposits on the surface. In addition, the mechanical properties of the molded product obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be set to a good value.

Further, the halogenated epoxy flame retardant of the present invention is preferably a brominated epoxy flame retardant.

As described above, the content of the organic solvent selected from the group consisting of toluene, methyl isobutyl ketone, methyl ethyl ketone, and acetone in the halogenated epoxy flame retardant of the present invention is 50 ppm or less. The content of the organic solvent is preferably 40 ppm or less, more preferably 30 ppm or less, further preferably 20 ppm or less, further preferably 10 ppm or less, and further preferably 8 ppm or less. Especially preferable. By setting the content of the organic solvent in the halogenated epoxy flame retardant within this range, the appearance of the molded product obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be improved. It is possible to suppress the generation of deposits on the screws of the extruder and the molding machine during molding, and eventually the mixing of the carbides. In addition, the mechanical properties of the molded product obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be set to a good value.

(Total content of epoxy groups in the entire flame-retardant polybutylene terephthalate resin composition)
As described above, the total content of epoxy groups in the entire flame-retardant polybutylene terephthalate resin composition of the present invention is 0.0155 mol / kg or less. The total content of epoxy groups in the entire composition is preferably 0.0150 mol / kg or less, more preferably 0.0145 mol / kg or less, and more preferably 0.0130 mol / kg or less. It is more preferably 0.0100 mol / kg or less, and particularly preferably 0.0100 mol / kg or less. By setting the total content of epoxy groups in the flame-retardant polybutylene terephthalate resin composition within this range, the appearance of the molded product obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be improved. It is possible to suppress the generation of deposits on the screws of the extruder and the molding machine during molding, and eventually the mixing of the carbides. In addition, the mechanical properties of the molded product obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be set to a good value.

(Flame retardant aid)
The flame-retardant polybutylene terephthalate resin composition of the present invention preferably further contains a flame-retardant aid. The flame retardant aid is not particularly limited, but a flame retardant aid selected from the group consisting of antimony pentoxide, antimony trioxide, and sodium antimonate is preferable, and antimony pentoxide and antimony trioxide are more preferable.

Further, for the purpose of preventing the spread of fire due to the dripping of the burned resin, it is also preferable to use a dripping inhibitor such as polytetrafluoroethylene together.

The range of addition of the halogenated epoxy flame retardant and the flame retardant aid to the resin is preferably 3 to 50 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin. It is more preferably about 40 parts by mass, and further preferably 10 to 30 parts by mass. The total content of the epoxy group may be determined in consideration of the content of the epoxy compound (epoxy resin or the like) added as a stabilizer or the like in addition to the halogenated epoxy flame retardant. The flame retardant aid is preferably in the range of 1 to 40 parts by mass. If the amount of the halogenated epoxy flame retardant and the flame retardant aid added is too small, sufficient flame retardancy cannot be imparted, and if it is too large, the mechanical properties of the molded product may be deteriorated.

((C) Dimensional accuracy improving agent) The flame-retardant polybutylene terephthalate resin composition of the present invention is used for (C-1) improving dimensional accuracy in order to suppress warpage deformation of a molded product made of the resin composition. A (C) dimensional accuracy improving agent consisting of an alloy resin and / or (C-2) dimensional accuracy improving filler is added.

As the alloy resin for improving dimensional accuracy, not only the shrinkage rate and / or the coefficient of linear expansion during molding and heat treatment is small, but also the processing temperature is close to that of the (A) polybutylene terephthalate resin, and the compatibility is compatible. A good resin can be preferably used. Examples of such (C-1) alloy resin for improving dimensional accuracy include polyamide resin, vinyl resin, polyurethane resin, polyketone resin, polyphenylene sulfide resin, polyether ether ketone resin, polycarbonate resin, and styrene resin (polystyrene resin, Acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, styrene-butadiene copolymer, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-ethylene-butadiene-styrene copolymer Other than coalescing, poly, etc.), polyarylate resin, polysulfone resin, polyethersulfone resin, phenoxy resin, polyphenylene ether resin, polyetherimide resin, polyamideimide resin, polyacetal resin, unsaturated polyester resin, urea resin, polybutylene terephthalate Polyester resin (polyethylene terephthalate resin, polypropylene terephthalate resin, polybutylene naphthalate resin, polyethylene naphthalate resin, polylactic acid resin, etc.), olefin-based elastoma, core-shell elastoma, diene elastoma, polyester-based elastoma, urethane-based elastoma, silicone-based Elastoma and combinations thereof can be mentioned. Among them, amorphous thermoplastic resins such as polyethylene terephthalate resin, polycarbonate resin, polyphenylene ether resin, and styrene resin are easy to obtain the effect of low warpage because the shrinkage rate of the molded product and its anisotropy are small. When the polybutylene terephthalate resin composition contains a liquid additive, it is particularly preferable because it also has an effect of suppressing bleed-out. In addition, in order to improve the affinity between these resins and the polybutylene terephthalate resin, a known compatibilizer may be used in combination.

As the styrene resin, one produced by any of bulk polymerization, solution polymerization, and suspension polymerization may be used, but from the viewpoint of improving dimensional accuracy, it is more preferable to use one produced by bulk polymerization. ..

Examples of the olefin-based elastoma include an ethylene-propylene copolymer (EP copolymer), an ethylene-butene copolymer, an ethylene-octene copolymer, and an ethylene-propylene-diene copolymer (EPD copolymer). Copolymers containing at least one unit selected from ethylene-propylene-butene copolymers, ethylene-vinyl acetate copolymers, EP copolymers and EPD copolymers, olefins and (meth) acrylic monomers Copolymers with (ethylene-ethyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, etc.) and the like are included. Preferred olefin-based elastomas include EP copolymers, EPD copolymers, and copolymers of olefins and (meth) acrylic monomers, with ethylene ethyl acrylate being particularly preferred. These olefin-based elastomers can be used alone or in combination of two or more.

The core-shell elastomer is a polymer in which the core layer is composed of a rubber component (soft component) and the shell layer is composed of a hard component, and acrylic rubber or the like is used as the rubber component of the core layer. The rubber component used for the core layer preferably has a glass transition temperature (Tg) of less than 0 ° C. (for example, -10 ° C. or lower), and preferably -20 ° C. or lower (for example, −180 ° C. or higher and -25 ° C. or lower). More preferably, it is −30 ° C. or lower (for example, −150 ° C. or higher and −40 ° C. or lower).

When an acrylic rubber is used as the rubber component, a polymer obtained by polymerizing an acrylic monomer such as alkyl acrylate as a main component is preferable. Alkyl acrylate used as the monomer of the acrylic rubber include alkyl esters of C1~C12 acrylic acid are preferred, such as butyl acrylate, alkyl esters of C ₂ -C ₆ acrylic acid is more preferable.

The acrylic rubber may be a homopolymer of an acrylic monomer or a copolymer. When the acrylic rubber is a copolymer of an acrylic monomer, it may be a copolymer of acrylic monomers or a copolymer of an acrylic monomer and another unsaturated bond-containing monomer. When the acrylic rubber is a copolymer, the acrylic rubber may be a copolymer of a crosslinkable monomer.

A vinyl polymer is preferably used for the shell layer. The vinyl-based polymer may be, for example, at least one monomer selected from an aromatic vinyl monomer, a vinyl cyanide monomer, a methacrylic acid ester-based monomer, and an acrylic acid ester monomer. Obtained by polymerization or copolymerization. The core layer and the shell layer of such a core-shell elastomer may be bonded by graft copolymerization. This graft copolymerization is obtained, if necessary, by adding a graft crossover that reacts with the shell layer during the polymerization of the core layer, imparting a reactive group to the core layer, and then forming the shell layer. When a silicone-based rubber is used as the graft crossing agent, an organosiloxane having a vinyl bond or an organosiloxane having a thiol is used, and acroxisiloxane, methacryoxysiloxane, and vinylsiloxane are preferably used.

As the polyester-based elastomer, either an ester-ester type having a polyester-based unit structure in both the hard segment and the soft segment and an ester-ester type having a soft segment having a polyether-based unit structure can be preferably used. The former is more preferable in terms of heat resistance, and the latter is more preferable in terms of dimensional accuracy.

(C-1) The amount of the alloy resin for improving dimensional accuracy added is 0 to 100 parts by mass, and may be 5 to 90 parts by mass or 10 to 80 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin. .. However, since a resin having low flame retardancy may deteriorate the flammability of the composition by adding a large amount, the content of the alloy resin for improving dimensional accuracy is the flame-retardant polybutylene terephthalate of the present invention. It is preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less with respect to the entire resin composition.

(C-2) As the filler for improving the dimensional accuracy, any of an organic filler, an inorganic filler, a metal filler and a combination thereof can be used, but the processing temperature range and use of the resin molded product Inorganic fillers and metal-based fillers having a small shrinkage rate and linear expansion coefficient in the temperature range are preferable, and in molded products used as insulating members to be combined with metal members, inorganic fillers are used to ensure insulating properties. Is particularly preferred.

(C-2) The shape of the filler for improving dimensional accuracy includes a fibrous filler, a plate-shaped filler, a spherical filler, a powder-like filler, a curved filler, an amorphous filler, or a combination thereof. However, in order to reduce warpage deformation, it is preferable to use a filler having a small anisotropy. Therefore, a plate-shaped filler, a spherical filler, a powder-like filler, etc., particularly having an aspect ratio of 1 can be used. It is more preferable to use a close filler. On the other hand, when a fibrous filler such as glass fiber is used, the effect of improving mechanical properties such as tensile strength is great, but due to the orientation of the fibrous filler, the shrinkage ratio anisotropy that causes warpage As a fibrous filler, short fibers such as milled fiber and whisker, and flat shapes such as cocoon-shaped, oval-shaped, and oval-shaped (for example, the ratio of major axis / minor axis of cross section is 1). It is more preferable to use fibers having a relatively small aspect ratio, such as fibers of .3 to 10).

Specific examples of the plate-shaped filler include plate-shaped talc, mica, glass flakes, metal pieces and combinations thereof, and specific examples of the spherical filler include glass beads, glass balloons, spherical silica and the like. Examples of the combination thereof include glass powder, talc powder, quartz powder, quartz powder, kaolin, clay, diatomaceous earth, wollastonite, silicon carbide, silicon nitride, metal powder, and inorganic acid metal. Salt (calcium carbonate, zinc borate, calcium borate, zinc nitrate, calcium sulfate, barium sulfate, etc.) powder, metal oxide (magnesium oxide, iron oxide, titanium oxide, zinc oxide, alumina, etc.) powder, metal Hydroxide (aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, alumina hydrate (bemite), etc.) powder, metal sulfide (zinc sulfide, molybdenum sulfide, tungsten sulfide, etc.) powder, and combinations thereof, etc. Can be mentioned. From the viewpoint of metal corrosiveness, it is preferable that the content of the free inorganic acid contained in these (C-2) fillers for improving dimensional accuracy is 0.5% by mass or less.

(C-2) The size of the filler for improving the dimensional accuracy can be appropriately selected in consideration of the balance between the warp reduction effect and the mechanical properties, fluidity and the like. For example, as talc, talc having a volume average particle diameter of 1 to 10 μm or compressed fine powder talc having a bulk specific gravity of 0.4 to 1.5 can be preferably used, and as mica, volume average particle diameter is 10 to 10. 60 μm mica can be preferably used.

These (C-2) dimensional accuracy improvers may be surface-treated (surface-coated) with an inorganic compound and / or an organic compound, and examples of the inorganic compound used for the surface treatment include aluminum hydroxide and alumina. , Silica, zirconia, zirconium hydroxide, zirconia hydrate, cerium oxide, cerium oxide hydrate, aluminum such as cerium hydroxide, inorganic oxides such as silicon, zirconium and cerium, and hydroxides are preferable. Moreover, these inorganic compounds may be hydrates. Among these, aluminum hydroxide and silica are preferable, and when silica is used, silica _{hydrate represented by SiO 2} · nH ₂ O is particularly preferable. The organic compound used for the surface treatment is not particularly limited, and known compounds such as amine compounds such as monoethanolamine, diethanolamine, triethanolamine, and dichlorohexylamine can be used.

The amount of the dimensional accuracy improving agent added (C-2) is 0 to 100 parts by mass, and may be 5 to 90 parts by mass or 10 to 80 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin. (C-2) The amount of the dimensional accuracy improving agent added can be appropriately selected in consideration of the balance between the warp reducing effect and the mechanical properties, fluidity and the like.

The amount of the (C) dimensional accuracy improving agent added, which is composed of the above-mentioned (C-1) alloy resin for improving dimensional accuracy and / or (C-2) filler for improving dimensional accuracy, is (C-1) for improving dimensional accuracy. The total of the alloy resin and the filler for improving the dimensional accuracy is 10 to 200 parts by mass, 20 to 180 parts by mass, or 50 to 150 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin. Is also good.

(Additive)
Further, a known substance generally added to a thermoplastic resin or the like can be added and used in combination with the composition of the present invention in order to impart various desired properties according to the purpose thereof. For example, stabilizers such as antioxidants, ultraviolet absorbers and light stabilizers, antistatic agents, lubricants, mold release agents, colorants such as dyes and pigments, plasticizers, fluidity improvers, toughness improvers, hydrolysis resistance. It is possible to blend any of a property improver, a flame retardant other than the halogenated epoxy flame retardant, a resin other than the alloy resin for improving dimensional accuracy, and the like.

When a phosphorus-based flame-retardant is added as a flame-retardant other than the halogenated epoxy-based flame-retardant, an organic phosphinic acid metal salt, an organic diphosphinic acid metal salt, and a condensed phosphoric acid ester (resorcinol phosphates, hydroquinone phosphates, biphenol phosphate) , Etc.), phosphazene compounds (cyclic phenoxyphosphazene, chain phenoxyphosphazene, crosslinked phenoxyphosphazene, etc.) can be used, and from the viewpoint of exudation from the molded product, aluminum ethylphosphite, aluminum diethylphosphazene, etc. Organic phosphinic acid metal salts such as aluminum methylethylphosphinate and zinc diethylphosphanate are preferred. When a halogen-based flame retardant is added as a flame retardant other than the halogenated epoxy-based flame retardant, a halogenated benzyl acrylate-based flame retardant, a halogenated phenoxy-based flame retardant, a halogenated polyphenylene ether-based flame retardant, or a halogenated styrene-based flame retardant Halogen-based flame retardants such as flame retardants, halogenated phthalimide-based flame retardants, and halogenated polycarbonate-based flame retardants can be mentioned, but from the viewpoint of metal corrosiveness, free bromine and free chlorine contained in these halogen-based flame retardants can be mentioned. , The content of free sulfur is preferably 0.5% by mass or less, respectively.

[Manufacturing method of flame-retardant polybutylene terephthalate resin composition]
The form of the flame-retardant polybutylene terephthalate resin composition of the present invention may be a powder or granular material mixture or a melt mixture (melt kneaded product) such as pellets. The method for producing the polybutylene terephthalate resin composition according to the embodiment of the present invention is not particularly limited, and it can be produced using equipment and methods known in the art. For example, the required components can be mixed and kneaded using a single-screw or twin-screw extruder or other melt-kneading device to prepare pellets for molding. Multiple extruders or other melt kneaders may be used. Further, all the components may be input from the hopper at the same time, or some components may be input from the side feed port.

Further, the flame-retardant polybutylene terephthalate resin composition of the present invention is vacuum-dried at the stage of each component (raw material) supplied to the above-mentioned melt-kneading and / or at the stage of pellets when molding a molded product. (Vacuum drying step) It is preferable to remove water. For vacuum drying, a commonly used evaporator, oven, or the like can be used.

[Molded product obtained from flame-retardant polybutylene terephthalate resin composition]
The flame-retardant polybutylene terephthalate resin composition of the present invention can be used for electrical and electronic components such as relays, switches, connectors, actuators, sensors, transbobins, terminal blocks, covers, switches, sockets, coils, plugs, and particularly power supplies. It can be preferably used as a peripheral component. Further, it is suitably used as a molding material for automobile parts such as in-vehicle parts cases such as ECU boxes and connector boxes and in-vehicle electrical components.

The method for obtaining a molded product using this flame-retardant polybutylene terephthalate resin composition is not particularly limited, and a known method can be adopted. For example, a flame-retardant polybutylene terephthalate resin composition is put into an extruder, melt-kneaded and pelletized, and the pellets are put into an injection molding machine equipped with a predetermined mold and injection-molded. Can be done.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded. The characteristic evaluation was performed by the following method.

(1) Flame retardancy The material dry-blended with the components and composition (parts by mass) shown in Table 1 is supplied to a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) having a screw of 30 mmφ and melted at 260 ° C. The pellets of the polybutylene terephthalate resin composition obtained by kneading were dried at 140 ° C. for 3 hours, and then injection molded at a cylinder temperature of 250 ° C. and a mold temperature of 70 ° C., conforming to UL94, and having a thickness of 1 A / 32 inch test piece was prepared and flammability was evaluated. The results are shown in Table 1.

(2) Low warpage The material dry-blended with the components and composition (parts by mass) shown in Table 1 is supplied to a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) having a screw of 30 mmφ and melted at 260 ° C. The pellets of the polybutylene terephthalate resin composition obtained by kneading were dried at 140 ° C. for 3 hours, and then in the form of a flat plate of 120 mm × 120 mm × 2 mm at a cylinder temperature of 260 ° C., a mold temperature of 60 ° C., and a holding pressure of 60 MPa. The test piece was injection molded. The obtained flat plate-shaped test piece was allowed to stand at 23 ° C. and 50% RH for 24 hours, and then placed on a surface plate. A total of 9 points were placed at the four corners and center of the upper surface and the central part (4 points) of each side. The coordinates in the height direction were measured with a CNC image measuring machine manufactured by Mitutoyo, and the amount of warpage of the molded product was calculated from the difference between the highest portion and the lowest portion. The case where the amount of warpage generated was 5 mm or less was evaluated as ⊚, the case where it was 10 mm or less was evaluated as ◯, and the case where it was more than 10 mm was evaluated as ×. The results are shown in Table 1.

(3) Screw deposits The pellets of the polybutylene terephthalate resin composition obtained in the same manner as in the flame retardancy evaluation were dried at 140 ° C. for 3 hours, and then melt-kneaded by the following procedure to obtain the amount of black deposits. The ones with remarkable occurrence of deposits were marked with "x", the ones with relatively few deposits were marked with "○", and the ones with relatively few deposits were marked with "◎". The results are shown in Table 1.
Step 1: Using a lab plast mill manufactured by Toyo Seiki Co., Ltd., the polybutylene terephthalate resin composition is extruded for 10 minutes at a cylinder temperature of 275 ° C. and a screw rotation speed of 20 rpm.
Step 2: Stop the screw while keeping the cylinder temperature at 275 ° C., and allow the polybutylene terephthalate resin composition in the cylinder to stay for 120 minutes.
Step 3: Purge with a polybutylene terephthalate resin composition for 10 minutes at a cylinder temperature of 275 ° C. and a screw rotation speed of 21 rpm.
Step 4: Purge with polyethylene resin for 5 minutes at a cylinder temperature of 275 ° C. and a screw rotation speed of 60 rpm.
Step 5: The cylinder temperature is 200 ° C., the screw rotation speed is 60 rpm, and the purging material "Rioclean-Z" manufactured by Toyo Color Co., Ltd. is used for purging for 5 minutes.
Step 6: Pull out the screw, wipe it gently with a cotton flannel to remove the purge material, and then observe the amount of black deposits on the screw.

(4) Bending Elastic Modulus The pellets of the polybutylene terephthalate resin composition obtained in the same manner as in the flame retardancy evaluation were dried at 140 ° C. for 3 hours, and then subjected to a cylinder temperature of 250 ° C. and a mold temperature of 70 ° C. A bending test piece of 80 mm × 10 mm × 4 mm is injection-molded, and a bending test is performed at a pressurizing speed of 2.0 mm / min and a distance between fulcrums of 64 mm according to ISO178, and a bending elastic modulus of 10,000 MPa or more is obtained. Those with "◯" and less than 10,000 MPa were evaluated as "x". The results are shown in Table 1.

表中の含有量の単位は、質量部である。

The unit of content in the table is parts by mass.

Details of each component shown in Table 1 are as follows.
(A) PBT resin: Polybutylene terephthalate resin (B-1) brominated epoxy flame retardant 1: epoxy equivalent 36800 g / g manufactured by Wintech Polymer Co., Ltd., with a terminal carboxyl group concentration of 20 meq / kg and an intrinsic viscosity of 0.7 dL / g. Brominated epoxy compound (B-2) brominated epoxy compound (B-2) brominated epoxy compound (B-2) with eq, organic solvent weight 5 ppm, weight average molecular weight about 18,000: Epoxy equivalent 43200 g / eq, organic solvent amount 0 ppm, weight average molecular weight about 20000 brominated epoxy Compound (B-3) Brominated Epoxy Flame Retardant 3: Epoxy Equivalent 28600 g / eq, Organic Solvent Amount 60 ppm, Weight Average Molecular Weight Approx. 9000 Brominated Epoxy Compound (B-4) Brominated Epoxy Flame Retardant 4: Epoxy Equivalent 19900g / eq, organic solvent amount 4ppm, weight average molecular weight about 23000 brominated epoxy compound (B'-1) brominated polyacrylate flame retardant: Pentabromobenzyl polyacrylate FR-1025 (epoxy equivalent 0g) manufactured by ICL JAPAN Co., Ltd. / Eq)
(C-1) Alloy resin for improving dimensional accuracy AS resin: Acrylonitrile-styrene resin 80HF manufactured by Ningbo LG Yongxing Chemical Co., Ltd.
PC resin: Made by Teijin, Polycarbonate resin Panlite L-1225W
PET resin: Made by Teijin, polyethylene terephthalate resin TRN-8550FF
(C-2) Filler talc for improving dimensional accuracy: Crown talc PP manufactured by Matsumura Sangyo Co., Ltd.
Glass flakes: Microglass FLECA REFG-301 manufactured by Nippon Sheet Glass Co., Ltd.
Flat cross section GF: Nitto Boseki, CSG3PA830 (Oval cross section with major axis 28 μm, minor axis 7 μm (major axis ÷ minor axis ratio = 4), oval cross section glass fiber with average fiber length 3 mm)
Circular cross section GF: manufactured by Nippon Electric Glass Co., Ltd., ECS03T-127 (average fiber diameter 13 μm, average fiber length 3 mm)
Antimony trioxide: manufactured by Nihon Seiko Co., Ltd., PATOX-M
Anti-dripping agent: Polytetrafluoroethylene epoxy resin (stabilizer): Mitsubishi Chemical Corporation, jER 1004K (epoxy equivalent 925 g / eq)

Claims (6)

(A) 100 parts by mass of polybutylene terephthalate resin and
(B) A halogenated epoxy flame retardant having an organic solvent content of 50 ppm or less selected from the group consisting of toluene, methyl isobutyl ketone, methyl ethyl ketone, and acetone.
(C-1) Dimensional accuracy improving agent (C-1) consisting of 0 to 100 parts by mass of alloy resin for improving dimensional accuracy and / or (C-2) packing material for improving dimensional accuracy 0 to 100 parts by mass, (C- A flame-retardant polybutylene terephthalate resin composition containing 10 to 200 parts by mass in total of 1) and (C-2).
A flame-retardant polybutylene terephthalate resin composition, characterized in that the total content of epoxy groups in the entire composition is 0.0155 mol / kg or less. (B) The flame-retardant polybutylene terephthalate resin composition according to claim 1, wherein the halogenated epoxy flame retardant has an epoxy equivalent of 30,000 g / eq or more. (B) The flame-retardant polybutylene terephthalate resin composition according to claim 1 or 2, wherein the content of the halogenated epoxy flame retardant is 3 to 50 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin. The flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 to 3, wherein the halogenated epoxy-based flame retardant is a brominated epoxy-based flame retardant. The flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 to 4, further containing a flame-retardant aid selected from the group consisting of antimony pentoxide, antimony trioxide, and sodium antimonate. A molded product obtained by injection molding the flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 to 5.