JP7454342B2 - Flame-retardant polybutylene terephthalate resin composition for electrical insulation parts - Google Patents

Description

The present invention relates to a flame-retardant polybutylene terephthalate resin composition for electrically insulating parts and molded articles thereof.

Polybutylene terephthalate resin (PBT resin) has excellent mechanical properties, electrical properties, heat resistance, and other properties, so it is widely used as an engineering plastic in various applications such as automobile parts and electric/electronic equipment parts. Among these, in applications for electrical and electronic equipment parts, the materials used are required to be flame retardant in order to prevent ignition due to tracking and the like. Polybutylene terephthalate resin lacks flame retardancy by itself, so it is used as a flame retardant resin composition with flame retardants added. In addition to the V-0 class flame retardance of the widely used UL94 standard, a higher level requirement is that the IEC60695-2 standard requires a glowing rod ignition temperature (GWIT) of 775°C or higher. It is being From this viewpoint, Patent Document 1 discloses a polybutylene terephthalate resin composition in which a halogen flame retardant such as talc, a brominated aromatic epoxy compound, and an antimony flame retardant aid are blended into a polybutylene terephthalate resin. There is.

By the way, Patent Document 2 introduces a method for producing a brominated epoxy compound flame retardant. This production method includes diglycidyl ethers of aromatic nucleus-containing alcohols, di- or polyglycidyl ethers of polyhydric phenols, diglycidyl esters of aromatic dibasic acids, monoglycidyl ethers of alkylphenols, and monoglycidyl ethers of hydroxybenzoic acids. Epoxy compounds having aromatic groups, such as ether esters, (β-methyl)epichlorohydrin addition products of p-aminophenol, or polyglycidylamines based on aromatic di- or polyamines, or their precursors. A chlorohydrin compound is brominated by bromine addition, and the obtained brominated bromohydrin compound or brominated chlorohydrin compound is subjected to ring-closing epoxidation through dehydrogenation or dehydrochlorination using an alkali metal hydroxide. It is characterized by

Further, Patent Document 3 introduces a brominated epoxy compound flame retardant for engineering thermoplastics. It is said that the molecular weight of this flame retardant is 7,000 to 50,000 Daltons, and the epoxy equivalent weight is preferably over 10,000 g/eq.

Furthermore, it is known that brominated epoxy compound flame retardants can increase in viscosity due to their own reactions, and the increase in viscosity during melt-kneading can cause deposits to form on the screws, and their carbides can be mixed into molded products. In order to suppress the occurrence of black speck (BS) due to this, the range of molecular weight and epoxy equivalent has been adjusted. For example, Patent Document 4 introduces that by using an epoxy compound with an epoxy equivalent of 600 to 1500 g/eq, the generation of black foreign matter in a molded article of a polybutylene terephthalate resin composition can be suppressed. Here, since polybutylene terephthalate resin compositions are used for electrical insulating parts that require a high GWIT as mentioned above, the inclusion of carbides promotes the formation of conductive paths and reduces insulation properties. Since there is a risk that this may occur, it is necessary to suppress this.

Japanese Patent Application Publication No. 2007-161946 Special Publication No. 60-016952 Patent No. 5143419 Patent No. 6100983

An object of the present invention is to suppress the contamination of black foreign matter (carbide) in a polybutylene terephthalate resin composition that contains a halogenated epoxy flame retardant as a flame retardant and constitutes a molded article used for electrically insulating parts. do.

As a result of intensive studies in the course of research to solve the above problems, the present inventors have discovered that flame retardant polybutylene terephthalate containing a specific nitrogen compound is used as a flame retardant, and a halogenated aromatic epoxy flame retardant is used as a flame retardant. In the resin composition, the above problems can be solved by controlling the content of the organic solvent in the halogenated epoxy flame retardant to a certain amount or less, and by controlling the total content of epoxy groups in the entire polybutylene terephthalate resin composition to a certain amount or less. The inventors have discovered that the problem can be solved, and have completed the present invention.

That is, the present invention relates to the following (1) to (6).
(1) A halogenated epoxy flame retardant containing 100 parts by mass of (A) polybutylene terephthalate resin and (B) an organic solvent selected from the group consisting of toluene, methyl isobutyl ketone, methyl ethyl ketone, and acetone at 50 ppm or less. 3 to 50 parts by mass, and (C) one or more types of nitrogen selected from a triazine compound, a benzoguanine compound, a terephthalic acid ester compound of tris(hydroxyalkyl)isocyanurate, an allantoin compound, a glycoluril compound, and a combination thereof. 5 to 80 parts by mass of a system compound, and (D) one or more types selected from magnesium silicate, aluminum silicate, zirconium silicate, calcium silicate, talc, and flat cross-section glass fiber with a length/breadth ratio of 1.5 to 8. silicate compounds, colemanite, one or more boron-based compounds selected from boron nitride, zinc borate, and calcium borate, and one or more metal hydroxides selected from magnesium hydroxide, aluminum hydroxide, and calcium hydroxide. 0 to 200 parts by mass of one or more flame retardant improvers selected from any one of the following and combinations thereof; and (E) selected from polyamide resins, polyarylene ether resins, liquid crystal polymers, and combinations thereof. A flame-retardant polybutylene terephthalate resin composition for electrical insulation parts containing 0 to 100 parts by mass of one or more flame-retardant improving alloy resins, wherein the total content of epoxy groups in the entire composition is 0. 1. A flame-retardant polybutylene terephthalate resin composition for electrically insulating parts, characterized in that it has a content of 0.0155 mol/kg or less.
(2) The flame-retardant polybutylene terephthalate resin composition for electrical insulation parts according to (1), wherein the epoxy equivalent of the halogenated epoxy flame retardant (B) is 30,000 g/eq or more.
(3) (B) The content of the halogenated epoxy flame retardant is from 3 to 50 parts by mass based on 100 parts by mass of the polybutylene terephthalate resin. Flammable polybutylene terephthalate resin composition.
(4) The flame-retardant polybutylene terephthalate resin composition for electrical insulation parts according to any one of (1) to (3), wherein the halogenated epoxy flame retardant (B) is a brominated epoxy flame retardant.
(5) The flame retardant for electrically insulating parts according to any one of (1) to (4), further containing a flame retardant aid selected from the group consisting of antimony pentoxide, antimony trioxide, and sodium antimonate. Polybutylene terephthalate resin composition.
(6) A molded article obtained by injection molding the flame-retardant polybutylene terephthalate resin composition for electrically insulating parts according to any one of (1) to (5).

According to the present invention, in a flame-retardant polybutylene terephthalate resin composition for electrical insulating parts that uses a halogenated epoxy flame retardant as a flame retardant, the content of organic solvent in the flame retardant is set to a certain amount or less, and the total content of epoxy groups in the entire flame-retardant polybutylene terephthalate resin composition for electrical insulating parts is set to a certain amount or less, thereby making it possible to obtain a flame-retardant polybutylene terephthalate resin composition for electrical insulating parts that has excellent electrical insulation properties and that suppresses the inclusion of black foreign matter (carbonized matter) in molded products made using the flame-retardant polybutylene terephthalate resin composition for electrical insulating parts.

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 implemented with appropriate modifications within a range that does not impede the effects of the present invention.

[Flame-retardant polybutylene terephthalate resin composition for electrical insulation parts]
Hereinafter, the details of each component of the flame-retardant polybutylene terephthalate resin composition for electrically insulating parts of this embodiment will be explained by giving examples.

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

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

(A) The inherent viscosity of the polybutylene terephthalate resin is not particularly limited as long as it does not impede the object of the present invention, but it 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 dL/g or less. When a polybutylene terephthalate resin having an intrinsic viscosity within this range is used, the resulting polybutylene terephthalate resin composition has particularly excellent moldability. The intrinsic viscosity can also be adjusted by blending polybutylene terephthalate resins having different intrinsic viscosities. For example, a polybutylene terephthalate resin with an intrinsic viscosity of 0.9 dL/g is prepared by blending a polybutylene terephthalate resin with an intrinsic viscosity of 1.0 dL/g and a polybutylene terephthalate resin with an intrinsic viscosity of 0.7 dL/g. I can do it. The intrinsic viscosity of polybutylene terephthalate resin can be measured, for example, in o-chlorophenol at a temperature of 35°C.

(A) In the preparation of polybutylene terephthalate resin, when an aromatic dicarboxylic acid other than terephthalic acid or an ester-forming derivative thereof is used as a comonomer component, for example, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4, C _8-14 aromatic dicarboxylic acids such as 4'-dicarboxydiphenyl ether; C _4-16 alkanedicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid; C _5-10 dicarboxylic acids such as cyclohexanedicarboxylic acid; Cycloalkanedicarboxylic acid: Ester-forming derivatives (C _1-6 alkyl ester derivatives, acid halides, etc.) of these dicarboxylic acid components 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 alkanedicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid are more preferred.

(A) In the preparation of polybutylene terephthalate resin, when using a glycol component other than 1,4-butanediol as a comonomer component, examples include ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol. _C2-10 alkylene glycols such as , neopentyl glycol, and 1,3-octanediol; polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol; alicyclics such as cyclohexanedimethanol and hydrogenated bisphenol A Diols; Aromatic diols such as bisphenol A and 4,4'-dihydroxybiphenyl; _C2-4 alkylene oxides of bisphenol A, such as 2 moles of ethylene oxide adducts of bisphenol A, and 3 moles of propylene oxide adducts of bisphenol A. Adducts; or ester-forming derivatives (acetylated products, etc.) of these glycols can be used. These glycol components can be used alone or in combination of two or more.

Among these glycol components, _C2-6 alkylene glycols such as ethylene glycol and trimethylene glycol, polyoxyalkylene glycols such as diethylene glycol, or alicyclic diols such as cyclohexanedimethanol are more preferred.

Comonomer components that can be used in addition to dicarboxylic acid components and glycol components include, for example, 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4-carboxy-4'-hydroxybiphenyl, etc. Aromatic hydroxycarboxylic acids; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; _C3-12 lactones such as propiolactone, butyrolactone, valerolactone, caprolactone (ε-caprolactone, etc.); esters of these comonomer components Formative derivatives (C _1-6 alkyl ester derivatives, acid halides, acetylated products, etc.) can be mentioned.

(A) The content of polybutylene terephthalate resin is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and 30 to 70% by mass of 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 improving 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. It is also possible to use any combination of two or more compounds as the epoxy compound.

The epoxy equivalent of the above epoxy compound is preferably 30,000 g/eq or more, more preferably 32,000 g/eq or more, even more preferably 34,000 g/eq or more. , more preferably 36,000 g/eq or more, particularly preferably 36,500 g/eq or more. By setting the epoxy equivalent within this range, the appearance of the molded product obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be made good, and the screw of the extruder or molding machine during molding can be improved. It is possible to suppress the occurrence of deposits on the surface. Moreover, the mechanical properties of molded articles obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be made to have good values.

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. Further, the content of the organic solvent is preferably 40 ppm or less, more preferably 30 ppm or less, even more preferably 20 ppm or less, even more preferably 10 ppm or less, and even more preferably 8 ppm or less. Particularly preferred. By controlling 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 occurrence of deposits on the extruder or the screw of the molding machine during molding, and the contamination of the carbide. Moreover, the mechanical properties of molded articles obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be made to have good values.

(Total content of epoxy groups in the entire flame-retardant polybutylene terephthalate resin composition)
As mentioned 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. Further, the total content of epoxy groups in the entire composition is preferably 0.0150 mol/kg or less, more preferably 0.0140 mol/kg or less, and even more preferably 0.0130 mol/kg or less. More preferably, it is particularly preferably 0.0120 mol/kg or less. By keeping the total content of epoxy groups in the entire 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. Therefore, it is possible to suppress the occurrence of deposits on the extruder or the screw of the molding machine during molding, and the contamination of the carbide. Moreover, the mechanical properties of molded articles obtained from the flame-retardant polybutylene terephthalate resin composition of the present invention can be made to have good values.

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

Furthermore, in order to prevent the spread of fire due to dripping of burned resin, it is also preferable to use a dripping prevention agent such as polytetrafluoroethylene.

The amount of the halogenated epoxy flame retardant added is preferably 3 to 50 parts by weight, more preferably 10 to 45 parts by weight, and 20 to 40 parts by weight based on 100 parts by weight of the polybutylene terephthalate resin. It is more preferable that it is part. The total content of epoxy groups may be determined by taking into consideration the content of epoxy compounds (such as epoxy resins) added as stabilizers in addition to the halogenated epoxy flame retardant. Further, the flame retardant aid is preferably in the range of 1 to 40 parts by weight per 100 parts by weight of the polybutylene terephthalate resin. If the amount of the halogenated epoxy flame retardant and flame retardant aid added is too small, sufficient flame retardancy cannot be imparted, and if the amount is too large, the mechanical properties of the molded product may deteriorate.

((C) Nitrogen compound)
The nitrogen-based compound (C) used in the present invention is added to improve the glowing rod ignition temperature (GWIT) according to the IEC60695-2 standard, which is required for electrical insulation parts.

Examples of the nitrogen-based compound (C) include triazine compounds, benzoguanine compounds, tris(hydroxyalkyl)isocyanurate terephthalate ester compounds, allantoin compounds, glycoluril compounds, and combinations thereof.

Specific examples of triazine compounds include cyanuric acid, trimethyl cyanurate, triethyl cyanurate, tri(n-propyl) cyanurate, methyl cyanurate, diethyl cyanurate, isocyanuric acid, trimethyl isocyanurate, triethyl isocyanurate, tri(n-propyl) cyanurate, -propyl) isocyanurate, diethyl isocyanurate, methyl isocyanurate, melamine, melamine cyanurate, melamine phosphate compounds, dimelamine phosphate compounds, melamine polyphosphate compounds, melamine sulfate, ammelide, ammeline, formoguanamine, guanylmelamine, cyanomelanine , arylguanamine, melam, melem, melon, etc.

(C) The amount of nitrogen compound added is 5 to 80 parts by weight, preferably 10 to 70 parts by weight, and more preferably 20 to 60 parts by weight, per 100 parts by weight of the polybutylene terephthalate resin. preferable.

((D) Flame retardancy improver) The flame retardant polybutylene terephthalate resin composition for electrical insulating parts of the present invention has a red hot rod ignition temperature (GWIT) of the IEC60695-2 standard, which is required for electrical insulating parts. In order to improve the flame retardancy, (D) a flame retardant improver is supplementarily added.

(D) Specific examples of flame retardancy improvers include silicate compounds such as magnesium silicate, aluminum silicate, zirconium silicate, calcium silicate, talc, and flat cross-section glass fibers with a length/breadth ratio of 1.5 to 8. , colemanite, boron-based compounds such as boron nitride, zinc borate, and calcium borate, and metal hydroxides such as magnesium hydroxide, aluminum hydroxide, and calcium hydroxide; any one of these or a combination of these can be used.

(D) The amount of flame retardancy improver added is 0 to 200 parts by weight, and may be 0 to 150 parts by weight or 0 to 100 parts by weight, based on 100 parts by weight of the polybutylene terephthalate resin.

((E) Alloy resin for improving flame retardancy) The flame-retardant polybutylene terephthalate resin composition for electrical insulating parts of the present invention has a red hot rod ignition temperature (GWIT) of the IEC60695-2 standard, which is required for electrical insulating parts. ), (E) alloy resin for improving flame retardancy is supplementarily added.

(E) As the alloy resin for improving flame retardancy, a resin that has better GWIT than (A) polybutylene terephthalate resin and has a processing temperature similar to that of polybutylene terephthalate resin can be used. (E) Specific examples of the alloy resin for improving flame retardancy include polyamide resins, polyarylene ether resins, liquid crystal polymers, and combinations thereof.

(E) The amount of the alloy resin for improving flame retardancy added is 0 to 100 parts by weight, and may be 0 to 90 parts by weight or 0 to 80 parts by weight, based on 100 parts by weight of the polybutylene terephthalate resin.

(Filler) A filler may be used in the composition of the present invention, if necessary. Such fillers are preferably blended in order to obtain excellent properties such as mechanical strength, heat resistance, dimensional stability, and electrical properties, and are particularly effective for increasing rigidity. Fibrous, powdery or plate-like fillers are used depending on the purpose.

Examples of fibrous fillers include circular cross-section glass fibers, asbestos fibers, carbon fibers, silica fibers, silica/alumina fibers, zirconia fibers, potassium titanate fibers, and metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. Examples include things. Note that organic fibrous substances with high melting points such as fluororesins and acrylic resins can also be used.

Examples of powdery fillers include glass beads, glass powder, quartz powder, kaolin, clay, diatomaceous earth, wollastonite, iron oxide, titanium oxide, alumina, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, and other silicon carbide. , silicon nitride, various metal powders, and the like.

Furthermore, examples of the plate-like inorganic filler include mica, glass flakes, and various metal foils.

The type of filler is not particularly limited, and one or more types of fillers can be added. In particular, it is preferable to use circular cross-section glass fibers, potassium titanate fibers, mica, and wollastonite.

Although the amount of the filler added is not particularly limited, it is preferably 200 parts by mass or less per 100 parts by mass of the polybutylene terephthalate resin. If too much filler is added, moldability is poor and toughness is decreased.

(Additive)
Furthermore, in order to impart desired properties other than flame retardancy to the composition of the present invention, depending on the purpose, known substances that are generally added to thermoplastic resins and the like may be added and used in combination. For example, antioxidants, ultraviolet absorbers, stabilizers such as light stabilizers, antistatic agents, lubricants, mold release agents, colorants such as dyes and pigments, plasticizers, fluidity improvers, toughness improvers, hydrolysis resistance. It is also possible to blend any of the resins other than the alloy resin for improving flame retardancy and the flame retardant improving agent.

[Method for producing flame-retardant polybutylene terephthalate resin composition for electrical insulation parts]
The form of the flame-retardant polybutylene terephthalate resin composition for electrically insulating parts of the present invention may be a powder mixture or a molten mixture (melt kneaded product) such as pellets. The method for producing the polybutylene terephthalate resin composition of one embodiment of the present invention is not particularly limited, and can be produced using equipment and methods known in the technical field. For example, the necessary components can be mixed and kneaded using a single-screw or twin-screw extruder or other melt-kneading equipment to prepare pellets for molding. A plurality of extruders or other melt-kneading devices may be used. Furthermore, all the components may be introduced from the hopper at the same time, or some components may be introduced from the side feed port.

Furthermore, the flame-retardant polybutylene terephthalate resin composition of the present invention is vacuum-dried at the stage of each component (raw material) to be supplied to the above-mentioned melt-kneading and/or at the stage of pellets when molded into a molded article. It is preferable to remove water by drying (vacuum drying step). For vacuum drying, a commonly used evaporator, oven, etc. 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, transformer bobbins, terminal blocks, covers, switches, sockets, coils, and plugs, especially power supplies. It can be preferably used as surrounding parts. Furthermore, it is suitably used as a molding material for automotive parts such as cases for automotive components such as ECU boxes and connector boxes, and automotive electrical components.

There is no particular limitation on the method for obtaining a molded article using this flame-retardant polybutylene terephthalate resin composition, and any known method can be employed. For example, a flame retardant polybutylene terephthalate resin composition is put into an extruder, melted and kneaded to form pellets, and the pellets are put into an injection molding machine equipped with a predetermined mold and injection molded. I can do it.

(Example)
Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. In addition, the characteristic evaluation was performed by the following method.
(1) Flame retardancy A dry-blended material 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.) with a 30 mmφ screw and melted at 260°C. After kneading and drying the obtained pellets of the polybutylene terephthalate resin composition at 140°C for 3 hours, injection molding was performed at a cylinder temperature of 250°C and a mold temperature of 70°C, and the resulting pellets conformed to UL94 and had a thickness of 1. /16 inch test pieces were prepared to evaluate flammability. The results are shown in Table 1.
(2) GWIT
A dry-blended material with the ingredients and composition (parts by mass) shown in Table 1 was supplied to a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) with a 30 mmφ screw and melted and kneaded at 260°C to obtain the obtained material. The pellets of the polybutylene terephthalate resin composition 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 to form evaluation test pieces (80 mm x 80 mm x 3 mm thick flat plate). , a flat plate of 1.5 mm in thickness, and a flat plate of 60 mm x 60 mm x 0.75 mm in thickness), and then evaluated according to the test method specified in IEC60695-2-13. In other words, the maximum temperature at the tip when a red-hot rod of a specified shape (a loop-shaped wire made of nickel/chromium = 80/20 with an outer diameter of 4 mm) is brought into contact with the rod for 30 seconds and the flame does not ignite or spread for more than 5 seconds. GWIT is defined as a temperature 25° C. higher than GWIT.
(3) Screw deposits Pellets of the polybutylene terephthalate resin composition obtained in the same manner as in the evaluation of flame retardancy were dried at 140°C for 3 hours, and then melt-kneaded according to the following procedure to determine the amount of black deposits. were visually observed, and those with a significant amount of deposits were rated "x", those with a relatively small amount were rated "○", and those with a small amount were rated "◎". The results are shown in Table 1.
Procedure 1: A polybutylene terephthalate resin composition is extruded for 10 minutes at a cylinder temperature of 275° C. and a screw rotation speed of 20 rpm using a Laboplast Mill manufactured by Toyo Seiki Co., Ltd.
Step 2: Stop the screw while maintaining the cylinder temperature at 275°C, and let the polybutylene terephthalate resin composition in the cylinder stay for 120 minutes.
Step 3: Purge with the 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: Purge for 5 minutes using the purging material "Rioclean-Z" manufactured by Toyo Color Co., Ltd. at a cylinder temperature of 200° C. and a screw rotation speed of 60 rpm.
Step 6: Pull out the screw, wipe it lightly with cotton flannel to remove the purge material, and then observe the amount of black deposits on the screw.
(4) Flexural modulus After drying the pellets of the polybutylene terephthalate resin composition obtained in the same manner as in the evaluation of flame retardancy at 140°C for 3 hours, at a cylinder temperature of 250°C and a mold temperature of 70°C, A bending test piece of 80 mm x 10 mm x 4 mm was injection molded, and a bending test was performed at a pressing speed of 2.0 mm/min and a distance between fulcrums of 64 mm according to ISO178, and the bending elastic modulus was 10,000 MPa or more. It was evaluated as "○", and those under 10,000 MPa were evaluated as "x". The results are shown in Table 1.

Details of each component listed in Table 1 are as follows.
(A) PBT resin: Polybutylene terephthalate resin manufactured by Wintec Polymer Co., Ltd., terminal carboxyl group concentration 20 meq/kg, intrinsic viscosity 0.7 dL/g (B-1) Brominated epoxy flame retardant 1: Epoxy equivalent 36800 g/ Brominated epoxy compound (B-2) Brominated epoxy flame retardant 2: Brominated epoxy compound with an epoxy equivalent of 43,200 g/eq, an organic solvent amount of 0 ppm, and a weight average molecular weight of about 20,000. Compound (B-3) Brominated epoxy flame retardant 3: Brominated epoxy compound with epoxy equivalent of 28,600 g/eq, organic solvent amount of 60 ppm, weight average molecular weight of about 9,000 (B-4) Brominated epoxy flame retardant 4: Epoxy equivalent Brominated epoxy compound (B'-1) with 19900 g/eq, organic solvent amount 4 ppm, weight average molecular weight about 23000 Brominated polyacrylate flame retardant: ICL JAPAN Co., Ltd., pentabromobenzyl polyacrylate FR-1025 (epoxy equivalent 0 g /eq)
(C) Nitrogen compound: Melamine cyanurate (Melapur MC50, manufactured by BASF)
(D-1) Flat cross-section glass fiber: Nittobo Co., Ltd., CSG 3PA-830 (long axis 28 μm, short axis 7 μm (long axis/short axis = 4))
(D-2) Talc: Crown Talc PP manufactured by Matsumura Sangyo Co., Ltd.
(E) Liquid crystal polymer: Polyplastics Co., Ltd., A950 (melting point 280°C)
Circular cross-section glass fiber: manufactured by Nippon Electric Glass Co., Ltd., ECS03T-127 (average fiber diameter 13 μm, average fiber length 3 mm)
Antimony trioxide: manufactured by Nippon Seiko Co., Ltd., PATOX-M
Antimony pentoxide: manufactured by Nissan Chemical Industries, Ltd., NA-1030
Anti-dripping agent: polytetrafluoroethylene epoxy resin (stabilizer): manufactured by Mitsubishi Chemical Corporation, jER 1004K (epoxy equivalent: 925 g/eq)

As shown in Table 1, all of the molded products obtained from the flame-retardant polybutylene terephthalate resin compositions of Examples 1 to 14 that satisfy the constitution of Claim 1 of the present application had excellent appearance and were screw-resistant during molding. No deposits were observed. In addition, all examples exhibited excellent bending elastic modulus.

On the other hand, the molded article obtained from the polybutylene terephthalate resin composition of Comparative Example 3 in which the content of the organic solvent in the halogenated epoxy flame retardant was outside the range of Claim 1 of the present application did not have an excellent appearance. Adherence to the screw occurred during molding.

In addition, the molded articles obtained from the polybutylene terephthalate resin compositions of Comparative Examples 1, 2, 4, and 5, in which the total content of epoxy groups in the entire composition is outside the range of Claim 1 of the present application, all have a poor appearance. It was not excellent, and deposits were observed on the screw during molding.

Furthermore, the molded article obtained from the polybutylene terephthalate resin composition of Comparative Example 6 using a brominated polyacrylate flame retardant had poor mechanical properties (flexural modulus).

Claims (6)

(A) 100 parts by mass of polybutylene terephthalate resin;
(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) 63 to 80 parts by mass of one or more nitrogen-based compounds selected from triazine compounds, benzoguanine compounds, tris (hydroxyalkyl)isocyanurate terephthalic acid ester compounds, allantoin compounds, glycoluril compounds, and combinations thereof and,
(D) One or more silicate compounds selected from magnesium silicate, aluminum silicate, zirconium silicate, calcium silicate, talc, flat cross-section glass fiber with a major axis/minor axis ratio of 1.5 to 8, colemanite, boron nitride , one or more boron-based compounds selected from zinc borate, calcium borate, one or more metal hydroxides selected from magnesium hydroxide, aluminum hydroxide, calcium hydroxide, or combinations thereof. 0 to 200 parts by mass of one or more selected flame retardancy improvers,
(E) 0 to 100 parts by mass of one or more alloy resins for improving flame retardancy selected from polyamide resins, polyarylene ether resins, liquid crystal polymers, and combinations thereof;
(B) A flame-retardant polybutylene terephthalate resin composition for electrical insulation parts containing an epoxy resin other than a halogenated epoxy flame retardant,
A flame-retardant polybutylene terephthalate resin composition for electrical insulation parts, characterized in that the total content of epoxy groups in the entire composition is 0.0155 mol/kg or less. The flame-retardant polybutylene terephthalate resin composition for electrical insulation parts according to claim 1, wherein the epoxy equivalent of the halogenated epoxy flame retardant (B) is 30,000 g/eq or more. The flame retardant for electrically insulating parts according to claim 1 or 2, wherein the content of the (B) halogenated epoxy flame retardant is 3 to 50 parts by mass based on 100 parts by mass of the (A) polybutylene terephthalate resin. Polybutylene terephthalate resin composition. The flame-retardant polybutylene terephthalate resin composition for electrical insulation parts according to any one of claims 1 to 3, wherein the halogenated epoxy flame retardant (B) is a brominated epoxy flame retardant. The flame-retardant polybutylene terephthalate for electrical insulation parts according to any one of claims 1 to 4, further comprising a flame-retardant aid selected from the group consisting of antimony pentoxide, antimony trioxide, and sodium antimonate. Resin composition. A molded article obtained by injection molding the flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 to 5.