JP2019006866A - Polybutylene terephthalate-based resin composition and molded product - Google Patents

Abstract

To provide a polybutylene terephthalate-based resin composition having a high level of flame retardancy and excellent in impact resistance, and to provide a molded product.SOLUTION: A polybutylene terephthalate-based resin composition contains, based on 100 pts.mass of (A) a polybutylene terephthalate resin, 5 to 50 pts.mass of (B) a bromine-based flame retardant and 3 to 15 pts.mass of (C) antimony trioxide, and has a maximum calorific value of 240 W/g or less as obtained from combustion heat quantity measurement in accordance with ASTMD7309, has a peak temperature at 420°C or less, preferably 412°C or less when it attains the maximum calorific value, has a flammability of V-0 as determined by UL94 vertical burning test on a specimen of 0.35 mm in thickness. Preferably, the composition further contains a boric acid metal salt, especially zinc borate, in an amount of 0.3 to 10 pts.mass based on 100 pts.mass of the polybutylene terephthalate resin.SELECTED DRAWING: None

Description

  The present invention relates to a polybutylene terephthalate resin composition and a molded body, and more particularly to a polybutylene terephthalate resin composition excellent in high flame retardancy and impact resistance and a molded body thereof.

  Polybutylene terephthalate resin is excellent in mechanical strength, chemical resistance, electrical insulation, etc., and has excellent heat resistance, moldability, and recyclability. Widely used in electrical parts and machine parts.

In particular, when used in electrical and electronic parts, automobile parts, other electrical parts and machine parts, higher flame retardancy is required.
As a method for flame-retarding polybutylene terephthalate resin, there is a method of blending a chlorine-based flame retardant, a phosphorus-based flame retardant or a bromine-based flame retardant as a flame retardant. However, chlorinated flame retardants have problems such as a large amount of smoke generated during combustion, and dioxins may be generated when used products are incinerated. Moreover, compounding the calcium salt or aluminum salt of phosphinic acid as a phosphorus flame retardant (patent documents 1 and 2) is also performed. However, this method has a problem that the fluidity is lowered by the blending of the flame retardant and the mechanical properties such as impact resistance are not sufficient.

A method of using a brominated flame retardant and using an antimony compound as a flame retardant aid (for example, Patent Documents 3 to 5) has also been adopted.
However, in recent years, electrical and electronic equipment parts have been required to have impact resistance with a thin wall and a high degree of flame resistance with a thin wall as the parts have been made smaller and thinner. In addition to the vertical combustion rank V-0 level, a higher level of flame retardancy is required, and a polybutylene terephthalate resin composition that sufficiently satisfies such a requirement is not necessarily obtained.

JP-A-8-73720 Japanese Patent Laid-Open No. 11-60924 JP 2004-263174 A JP 2006-45544 A JP 2006-56997 A

  In view of the above circumstances, an object (problem) of the present invention is to provide a polybutylene terephthalate resin composition excellent in high flame retardancy and impact resistance.

The present inventors have conducted various studies on a resin composition containing a brominated flame retardant and antimony trioxide in polybutylene terephthalate resin, and as a result, the maximum calorific value of the resin composition determined by combustion calorimetry and its The polybutylene terephthalate resin composition with a peak temperature of the maximum exothermic peak below a specific energy level and below a specific temperature exhibits a high level of flame retardancy, and brominated flame retardants have a high level of flame retardancy. Even when it is contained in an amount that expresses, it has been found that the impact resistance can be maintained at a high level, and the present invention has been achieved.
The present invention is as follows.

[1] (A) 100 parts by mass of polybutylene terephthalate resin, (B) 5 to 50 parts by mass of brominated flame retardant, (C) 3 to 15 parts by mass of antimony trioxide, and according to ASTM D7309 The maximum calorific value obtained from the measurement of the calorific value is 240 W / g or less, the peak temperature at the maximum exotherm is 420 ° C. or less, and the flame retardancy in the UL94 vertical combustion test at 0.35 mm thickness is V-0. A polybutylene terephthalate resin composition characterized by the above. [2] The polybutylene terephthalate resin composition according to the above [1], wherein the peak temperature during the maximum heat generation is 412 ° C. or lower.
[3] The polybutylene terephthalate resin composition according to the above [1] or [2], which has a notched Charpy impact strength of 7 kJ / m ² or more measured at 23 ° C. according to ISO 179.
[4] Furthermore, (D) the boric acid metal salt is contained in 0.3 to 10 parts by mass with respect to 100 parts by mass of (A) polybutylene terephthalate resin. A butylene terephthalate resin composition.
[5] The polybutylene terephthalate resin composition according to the above [4], wherein the metal borate (D) is a zinc borate.
[6] The polybutylene terephthalate resin composition according to any one of [1] to [5], wherein the brominated flame retardant (B) is a polybrominated benzyl (meth) acrylate flame retardant.
[7] The polybutylene terephthalate-based resin composition according to any one of [1] to [6], wherein (C) antimony trioxide is blended as a master batch.
[8] The polybutylene terephthalate resin composition according to any one of [1] to [7], wherein the content of alkali metal and alkaline earth metal in (D) borate metal salt is 2,000 ppm by mass or less. object.
[9] The polybutylene terephthalate according to any one of [1] to [8], further including glass fibers having a fiber length of 0.3 to 10 mm and an average fiber diameter of 3 to 20 μm and a circular cross section. -Based resin composition.
[10] A molded article of the polybutylene terephthalate resin composition according to any one of [1] to [9].
[11] The molded article according to the above [10], wherein the molded article is an electric / electronic device component.
[12] The above [10] or [11], wherein the molded body is any one selected from the group consisting of a connector part, a relay part, a switch part, a breaker part, an electromagnetic switch part, and a terminal block part. The molded product according to 1.

The polybutylene terephthalate resin composition of the present invention contains (A) a polybutylene terephthalate resin, (B) a brominated flame retardant, and (C) antimony trioxide, respectively, and combusts in accordance with ASTM D7309. The maximum calorific value obtained from calorimetry is 240 W / g or less, and by setting the peak temperature at the maximum exotherm to 420 ° C. or less, high flame retardancy can be achieved, and brominated flame retardants are highly flame retardant. Even if it is contained in an amount that expresses, a high level of impact resistance can be maintained.
Therefore, the polybutylene terephthalate resin composition of the present invention is an insulating part for electrical and electronic equipment, for example, a connector part, a relay part, a switch part, a breaker part, an electromagnetic switch part, and a terminal block part. Etc., and can be particularly preferably used.

  Although the mechanism by which the resin composition of the present invention exerts such an effect has not been sufficiently analyzed yet, the maximum heat generation amount and the peak temperature at the maximum heat generation are set as described above, so that the It is considered that the diffusion of combustion can be suppressed. By setting the maximum calorific value to 240 W / g or less, the combustion energy decreases, so that the amount of active radicals generated by decomposition during combustion can be reduced, the continuity of combustion can be suppressed, and the peak temperature at the maximum exotherm can be reduced. The temperature at which the maximum calorific value is generated can be lowered by setting the temperature to 420 ° C. or lower. Therefore, even if there is dripping at the time of combustion, the combustion temperature tends to drop relatively quickly when it is away from the flame. It is thought that ignition can be suppressed.

It is a graph which shows the relationship between the emitted-heat amount (W / g) calculated | required from combustion calorie | heat amount measurement, and temperature (degreeC).

The polybutylene terephthalate resin composition of the present invention comprises (A) 100 parts by mass of polybutylene terephthalate resin, (B) 5-50 parts by mass of a brominated flame retardant, and (C) 3-15 parts by mass of antimony trioxide. Contained, maximum calorific value obtained from combustion calorimetry in accordance with ASTM D7309 is 240 W / g or less, peak temperature at maximum exotherm is 420 ° C. or less, difficult by UL94 vertical combustion test at 0.35 mm thickness The flammability is V-0.
Combustion calorimetry is a thermal analysis technology that identifies the combustion characteristics of combustible materials represented by resin, controls the heat generation of minute samples, performs thermal oxidation of gas generated from samples, and tracks oxygen consumption Is an analysis method for measuring the calorific value, and details of the measurement method will be described later.

Hereinafter, the contents of the present invention will be described in detail.
The description of each constituent element described below may be made based on typical embodiments and specific examples of the present invention, but the present invention is interpreted to be limited to such embodiments and specific examples. It is not a thing. In the specification of the present application, “to” is used in the sense of including the numerical values described before and after it as the lower limit value and the upper limit value.

[(A) Polybutylene terephthalate resin]
The (A) polybutylene terephthalate resin used in the resin composition of the present invention is a polyester resin having a structure in which a terephthalic acid unit and a 1,4-butanediol unit are ester-bonded, and is a polybutylene terephthalate resin (homopolymer). In addition, the polybutylene terephthalate copolymer containing other copolymerization components other than a terephthalic acid unit and a 1, 4- butanediol unit, and the mixture of a homopolymer and the said copolymer are included.

  (A) The polybutylene terephthalate resin may contain dicarboxylic acid units other than terephthalic acid. Specific examples of other dicarboxylic acids include isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2, 5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2,2′-dicarboxylic acid, biphenyl-3,3′-dicarboxylic acid, biphenyl-4,4′-dicarboxylic acid, bis (4,4 ′ -Carboxyphenyl) aromatic dicarboxylic acids such as methane, anthracene dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 4,4'-dicyclohexyldicarboxylic acid And aliphatic such as adipic acid, sebacic acid, azelaic acid, dimer acid, etc. Carboxylic acids, and the like.

  The diol unit may contain other diol units in addition to 1,4-butanediol, but specific examples of other diol units include aliphatic or alicyclic diols having 2 to 20 carbon atoms. And bisphenol derivatives. Specific examples include ethylene glycol, propylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, decamethylene glycol, cyclohexanedimethanol, 4,4′-dicyclohexylhydroxymethane, 4 4,4'-dicyclohexylhydroxypropane, ethylene oxide addition diol of bisphenol A, and the like. Furthermore, triols such as glycerin and trimethylolpropane are also included.

  (A) The polybutylene terephthalate resin is preferably a polybutylene terephthalate homopolymer obtained by polycondensation of terephthalic acid and 1,4-butanediol. In addition, as the carboxylic acid unit, a dicarboxylic acid 1 other than the terephthalic acid is used. The polybutylene terephthalate copolymer containing 1 or more types of diols other than the said 1, 4- butanediol as a seed | species and / or diol unit may be sufficient. In the (A) polybutylene terephthalate resin, the proportion of terephthalic acid in the dicarboxylic acid unit is preferably 70 mol% or more, more preferably 90 mol% or more, from the viewpoint of mechanical properties and heat resistance. Similarly, the proportion of 1,4-butanediol in the diol unit is preferably 70 mol% or more, more preferably 90 mol% or more.

  In addition to the above-mentioned bifunctional monomers, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane are introduced to introduce a branched structure, and fatty acids are used for molecular weight control. A small amount of a monofunctional compound can be used in combination.

(A) The polybutylene terephthalate resin may be a polybutylene terephthalate resin modified by copolymerization, but as a specific preferred copolymer thereof, polyalkylene glycols, particularly polytetramethylene glycol is copolymerized. Polyester ether resin, dimer acid copolymerized polybutylene terephthalate resin, and isophthalic acid copolymerized polybutylene terephthalate resin. These copolymers are those having a copolymerization amount of 1 mol% or more and less than 50 mol% in all segments of the polybutylene terephthalate resin. Among them, the copolymerization amount is preferably 2 to 50 mol%, more preferably 3 to 40 mol%, and particularly preferably 5 to 20 mol%.
(A) When using a copolymer as a polybutylene terephthalate resin, it is preferable to use especially the polyester ether resin which copolymerized polytetramethylene glycol. The proportion of the tetramethylene glycol component in the copolymerization is preferably 3 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 25% by mass.

(A) Polybutylene terephthalate resin is a melt polymerization of a dicarboxylic acid component containing terephthalic acid as a main component or an ester derivative thereof and a diol component containing 1,4-butanediol as a main component in a batch or continuous manner. Can be manufactured. Further, after the low molecular weight polybutylene terephthalate resin is produced by melt polymerization, the degree of polymerization (or molecular weight) can be increased to a desired value by further solid-phase polymerization under a nitrogen stream or under reduced pressure.
(A) The polybutylene terephthalate resin is obtained by a production method in which a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing 1,4-butanediol as a main component are melt polycondensed in a continuous manner. Is preferred.

  The catalyst used in performing the esterification reaction may be a conventionally known catalyst, and examples thereof include a titanium compound, a tin compound, a magnesium compound, and a calcium compound. Of these, titanium compounds are particularly preferred. Specific examples of the titanium compound as the esterification catalyst include titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate, and titanium phenolates such as tetraphenyl titanate.

  In (A) polybutylene terephthalate resin, the amount of terminal carboxyl groups may be appropriately selected and determined. Usually, it is 60 eq / ton or less, preferably 50 eq / ton or less, and 30 eq / ton or less. More preferably. If it exceeds 50 eq / ton, gas tends to be generated during melt molding of the resin composition. Although the lower limit of the amount of terminal carboxyl groups is not particularly defined, it is usually 10 eq / ton in consideration of the productivity of production of polybutylene terephthalate resin.

  The amount of terminal carboxyl groups of the polybutylene terephthalate resin is a value measured by titration using a 0.01 mol / l benzyl alcohol solution of sodium hydroxide by dissolving 0.5 g of the polyalkylene terephthalate resin in 25 mL of benzyl alcohol. is there. As a method for adjusting the amount of terminal carboxyl groups, a conventionally known arbitrary method such as a method for adjusting polymerization conditions such as a raw material charge ratio during polymerization, a polymerization temperature, a pressure reduction method, a method for reacting a terminal blocking agent, etc. Just do it.

(A) The intrinsic viscosity of the polybutylene terephthalate resin is preferably 0.5 to 2 dl / g. From the viewpoint of moldability and mechanical properties, those having an intrinsic viscosity in the range of 0.6 to 1.5 dl / g are more preferable. If the intrinsic viscosity is lower than 0.5 dl / g, the resulting resin composition tends to have a low mechanical strength. On the other hand, if it is higher than 2 dl / g, the fluidity of the resin composition may deteriorate and the moldability may deteriorate.
The intrinsic viscosity of (A) polybutylene terephthalate resin is a value measured at 30 ° C. in a 1: 1 (mass ratio) mixed solvent of tetrachloroethane and phenol.

[(B) Brominated flame retardant]
The polybutylene terephthalate resin composition of the present invention contains (B) a brominated flame retardant. (B) Various types of brominated flame retardants can be used. Such brominated flame retardants include aromatic compounds, specifically, for example, polybrominated benzyl (meth) acrylates such as polypentabromobenzyl acrylate, polybromophenylene ether, brominated polystyrene, Examples thereof include brominated epoxy compounds such as tetrabromobisphenol A epoxy oligomer, brominated imide compounds such as N, N′-ethylenebis (tetrabromophthalimide), and brominated polycarbonate.

Among them, from the viewpoint of good thermal stability, polybrominated benzyl (meth) acrylates such as polypentabromobenzyl acrylate, brominated epoxy compounds such as tetrabromobisphenol A epoxy oligomer, brominated polystyrene, and brominated polycarbonate are preferable. Polybrominated benzyl (meth) acrylate, brominated epoxy compound and brominated polycarbonate are more preferred, polybrominated benzyl (meth) acrylate and brominated polycarbonate are particularly preferred, and polybrominated benzyl (meth) acrylate is most preferred.
When the polybrominated benzyl (meth) acrylate flame retardant is included, the content ratio of the polybrominated benzyl (meth) acrylate flame retardant in (B) the brominated flame retardant is preferably 70% by mass or more, and 80 More preferably, it is more preferably 90% by mass or more, and most preferably (B) all brominated flame retardants are polybrominated benzyl (meth) acrylate flame retardants.

  As a polybrominated benzyl (meth) acrylate, a polymer obtained by polymerizing benzyl (meth) acrylate containing a bromine atom alone, copolymerizing two or more kinds, or copolymerizing with other vinyl monomers It is preferable that the bromine atom is added to the benzene ring, and the number of addition is preferably 1 to 5, more preferably 4 to 5 per benzene ring.

  Examples of the benzyl acrylate containing a bromine atom include pentabromobenzyl acrylate, tetrabromobenzyl acrylate, tribromobenzyl acrylate, and mixtures thereof. Examples of the benzyl methacrylate containing a bromine atom include methacrylates corresponding to the acrylates described above.

  Specific examples of other vinyl monomers used for copolymerization with benzyl (meth) acrylates containing bromine atoms include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and benzyl acrylate. Acrylic esters; methacrylic esters such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, benzyl methacrylate; unsaturated carboxylic acids such as styrene, acrylonitrile, fumaric acid, maleic acid or anhydrides thereof; Examples include vinyl acetate and vinyl chloride.

  These are usually preferably used in an equimolar amount or less, particularly 0.5 times the molar amount or less with respect to benzyl (meth) acrylate containing a bromine atom.

  In addition, xylene diacrylate, xylene dimethacrylate, tetrabromoxylene diacrylate, tetrabromoxylene dimethacrylate, butadiene, isoprene, divinylbenzene, etc. can be used as vinyl monomers, and these usually contain bromine atoms. 0.5 mol or less of benzyl acrylate or benzyl methacrylate can be used.

  As the polybrominated benzyl (meth) acrylate, pentabromobenzyl polyacrylate is preferable from the viewpoint of high bromine content and high electrical insulation characteristics (tracking resistance).

  Specific examples of brominated epoxy compounds include bisphenol A brominated epoxy compounds represented by tetrabromobisphenol A epoxy compounds.

The molecular weight of the brominated epoxy compound is arbitrary and may be appropriately selected and determined. Preferably, the molecular weight is 3,000 to 100,000 in terms of mass average molecular weight (Mw). Specifically, the Mw is preferably 10,000 to 80,000, more preferably 13,000 to 78,000, more preferably 15,000 to 75,000, and particularly preferably 18,000 to 70,000. Of these, those having a high molecular weight are preferred.
The brominated epoxy compound preferably has an epoxy equivalent of 3,000 to 40,000 g / eq, more preferably 4,000 to 35,000 g / eq, and particularly preferably 10,000 to 30,000 g / eq. It is preferable.

  Moreover, a brominated epoxy oligomer can also be used together as a brominated epoxy compound flame retardant. At this time, for example, by using about 0 to 50% by mass of an oligomer having Mw of 5,000 or less, flame retardancy, mold release property and fluidity can be appropriately adjusted. Although the bromine atom content in the brominated epoxy compound is arbitrary, it is usually 10% by mass or more, preferably 20% by mass or more, particularly preferably 30% by mass or more, in order to impart sufficient flame retardancy. The upper limit is 60% by mass, preferably 55% by mass or less.

  Specifically, the brominated polycarbonate flame retardant is preferably a brominated polycarbonate obtained from, for example, brominated bisphenol A, particularly tetrabromobisphenol A. Examples of the terminal structure include a phenyl group, 4-t-butylphenyl group, 2,4,6-tribromophenyl group, etc., and particularly those having a 2,4,6-tribromophenyl group in the terminal group structure. Is preferred.

  The average number of carbonate repeating units in the brominated polycarbonate flame retardant may be appropriately selected and determined, but is usually 2 to 30. If the average number of carbonate repeating units is small, the molecular weight of the (A) polybutylene terephthalate resin may be lowered during melting. On the other hand, if it is too large, the melt viscosity becomes high, causing poor dispersion in the molded body, and the appearance of the molded body, particularly glossiness, may be lowered. Therefore, the average number of repeating units is preferably 3 to 15, particularly 3 to 10.

  The molecular weight of the brominated polycarbonate-based flame retardant is arbitrary and may be appropriately selected and determined. Preferably, the viscosity average molecular weight is 1,000 to 20,000, and particularly 2,000 to 10,000. preferable.

  The brominated polycarbonate flame retardant obtained from the brominated bisphenol A can be obtained, for example, by a usual method of reacting brominated bisphenol A and phosgene. Examples of the end-capping agent include aromatic monohydroxy compounds, which may be substituted with a halogen or an organic group.

The brominated polystyrene preferably includes brominated polystyrene containing a repeating unit represented by the following general formula (1).
(In formula (1), t is an integer of 1 to 5, and n is the number of repeating units.)

Brominated polystyrene may be either brominated polystyrene or produced by polymerizing brominated styrene monomers, but the brominated styrene polymerized is free bromine (atoms). This is preferable because of the small amount.
In the general formula (1), the CH group to which brominated benzene is bonded may be substituted with a methyl group. The brominated polystyrene may be a copolymer obtained by copolymerizing another vinyl monomer. Examples of the vinyl monomer in this case include styrene, α-methylstyrene, acrylonitrile, methyl acrylate, butadiene, and vinyl acetate. Moreover, brominated polystyrene may be used as a single substance or a mixture of two or more different structures, and may contain units derived from styrene monomers having different numbers of bromines in a single molecular chain.

  Specific examples of brominated polystyrene include, for example, poly (4-bromostyrene), poly (2-bromostyrene), poly (3-bromostyrene), poly (2,4-dibromostyrene), poly (2,6 -Dibromostyrene), poly (2,5-dibromostyrene), poly (3,5-dibromostyrene), poly (2,4,6-tribromostyrene), poly (2,4,5-tribromostyrene) , Poly (2,3,5-tribromostyrene), poly (4-bromo-α-methylstyrene), poly (2,4-dibromo-α-methylstyrene), poly (2,5-dibromo-α- Methyl (styrene), poly (2,4,6-tribromo-α-methylstyrene), poly (2,4,5-tribromo-α-methylstyrene) and the like, and poly (2,4,6-tribromostyrene). And poly (2,4,5-tribromostyrene) and polydibromostyrene and polytribromostyrene containing an average of 2 to 3 bromine groups in the benzene ring are particularly preferably used.

In the brominated polystyrene, the number n (average polymerization degree) of the repeating units in the general formula (1) is preferably 30 to 1,500, more preferably 150 to 1,000, particularly 300 to 800. Is preferred. If the average degree of polymerization is less than 30, blooming tends to occur. On the other hand, if it exceeds 1,500, poor dispersion tends to occur and the mechanical properties tend to deteriorate. The mass average molecular weight (Mw) of brominated polystyrene is preferably 5,000 to 500,000, more preferably 10,000 to 500,000, and 10,000 to 300,000. More preferably, it is preferably 10,000 to 70,000.
In particular, in the case of the brominated polystyrene described above, the mass average molecular weight (Mw) is preferably 50,000 to 70,000, and in the case of brominated polystyrene by a polymerization method, the mass average molecular weight (Mw) is 10,000. It is preferably about 30,000. In addition, a mass average molecular weight (Mw) can be calculated | required as a value of standard polystyrene conversion by GPC measurement.

  The brominated polystyrene preferably has a bromine concentration of 52 to 75% by mass, more preferably 56 to 70% by mass, and even more preferably 57 to 67% by mass. By setting the bromine concentration in such a range, it is easy to keep good flame retardancy.

As a brominated imide compound, what is represented by following General formula (2) is preferable.
(In General Formula (2), D represents an alkylene group, an alkyl ether group, a diphenyl sulfone group, a diphenyl ketone group or a diphenyl ether group. I is an integer of 1 to 4.)

  Examples of the brominated phthalimide compound represented by the general formula (2) include N, N ′-(bistetrabromophthalimide) ethane, N, N ′-(bistetrabromophthalimide) propane, N, N ′-(bis Tetrabromophthalimide) butane, N, N ′-(bistetrabromophthalimide) diethyl ether, N, N ′-(bistetrabromophthalimide) dipropyl ether, N, N ′-(bistetrabromophthalimide) dibutyl ether, N , N ′-(bistetrabromophthalimide) diphenyl sulfone, N, N ′-(bistetrabromophthalimide) diphenyl ketone, N, N ′-(bistetrabromophthalimide) diphenyl ether, and the like.

As the brominated imide compound, in the above general formula (2), those in which D is an alkylene group are preferable, and a brominated phthalimide compound represented by the following general formula (3) is particularly preferable.
(In general formula (3), i is an integer of 1 to 4.)
Among them, N, N′-ethylenebis (tetrabromophthalimide) in which i in the above formula (3) is 4 is preferable.

  The brominated imide compound preferably has a bromine concentration of 52 to 75% by mass, more preferably 56 to 73% by mass, and even more preferably 57 to 70% by mass. By setting the bromine concentration in such a range, it is easy to keep good flame retardancy.

  The content of (B) brominated flame retardant is 5 to 50 parts by mass, preferably 7 parts by mass or more, more preferably 10 parts by mass or more, relative to 100 parts by mass of (A) polybutylene terephthalate resin. Preferably it is 45 mass parts or less, More preferably, it is 40 mass parts or less, More preferably, it is 35 mass parts or less. (B) If the content of brominated flame retardant is too small, the flame retardancy of the resin composition becomes insufficient. Arise.

[(C) Antimony trioxide]
The polybutylene terephthalate resin composition of the present invention contains (C) antimony trioxide. Examples of the antimony compound include antimony trioxide (Sb ₂ O ₃ ), antimony pentoxide (Sb ₂ O ₅ ), and sodium antimonate. In the present invention, among these, antimony trioxide is contained.

  (C) Antimony trioxide has a mass ratio of (B) bromine-based flame retardant-derived bromine atom in the resin composition and (C) antimony trioxide in antimony trioxide in a total amount of 3 to 25% by mass. It is preferable to mix | blend so that it may become, It is more preferable that it is 4-22 mass%, It is further more preferable that it is 10-20 mass%. If it is less than 3% by mass, the flame retardancy tends to decrease, and if it exceeds 25% by mass, the mechanical strength tends to decrease. The mass ratio (Br / Sb) of bromine atoms and antimony atoms is preferably 0.3 to 5, and more preferably 0.3 to 4. By setting it as such a range, it exists in the tendency for a flame retardance to express easily, and it is preferable.

In the present invention, (C) antimony trioxide is preferably used as a master batch, and is preferably blended as a master batch with a thermoplastic resin, preferably (A) a polybutylene terephthalate resin. Thereby, (C) antimony trioxide is likely to be present in the (A) polybutylene terephthalate resin phase, the thermal stability at the time of melt-kneading and molding is improved, the reduction in impact resistance is suppressed, Variations in flame retardancy and impact resistance tend to be reduced.
The content of (C) antimony trioxide in the master batch is preferably 20 to 90% by mass. (C) When the amount of antimony trioxide is less than 20% by mass, the proportion of the antimony compound in the flame retardant master batch is small, and (A) the flame retardant improvement effect to the polybutylene terephthalate resin containing this tends to be small. . On the other hand, when (C) antimony trioxide exceeds 90% by mass, the dispersibility of (C) antimony trioxide tends to be lowered, and when this is blended with (A) polybutylene terephthalate resin, the flame retardancy of the resin composition It becomes unstable, and the workability at the time of manufacturing the master batch is likely to deteriorate. For example, when manufacturing using an extruder, the strand is not stable, and problems such as easy breakage are likely to occur. .
The content of (C) antimony trioxide in the masterbatch is preferably 20 to 85% by mass, more preferably 25 to 80% by mass.

  The content of (C) antimony trioxide is 3 to 15 parts by weight, preferably 4 parts by weight or more, more preferably 5 parts by weight or more, based on 100 parts by weight of (A) polybutylene terephthalate resin. Is 13 parts by mass or less, more preferably 10 parts by mass or less. If it falls below the lower limit, the flame retardancy is lowered. On the other hand, when the above upper limit is exceeded, the crystallization temperature is lowered and the releasability is deteriorated, and mechanical properties such as impact resistance are lowered.

(D) Boric acid metal salt The resin composition of the present invention preferably contains (D) a boric acid metal salt, and the content thereof is 0.3 to 10 mass relative to 100 mass parts of (A) polybutylene terephthalate resin. Part. Moreover, it is preferable that mass ratio (C / D) of content of (C) antimony trioxide and (D) metal borate is in the range of 1-20. (D) By containing the boric acid metal salt in such an amount and mass ratio, it becomes possible to improve the feed property at the time of melt-kneading, the dispersibility of the resin composition, and the combustibility, and also in the laser printability. Excellent. The C / D ratio is preferably 2-18, more preferably 4-16.

  (D) The boric acid forming the boric acid metal salt is preferably non-condensed boric acid such as orthoboric acid or metaboric acid; condensed boric acid such as pyroboric acid, tetraboric acid, pentaboric acid and octaboric acid; and basic boric acid. The metal that forms a salt with these may be an alkali metal, but among them, polyvalent metals such as alkaline earth metals, transition metals, and Group 2B metals of the periodic table are preferred. Further, (D) the boric acid metal salt is preferably a hydrate.

  (D) As boric acid metal salts, there are non-condensed boric acid metal salts, condensed boric acid metal salts, and basic boric acid metal salts. Non-condensed boric acid metal salts include alkaline earths such as calcium orthoborate and calcium metaborate. Metal borate; transition metal borates such as manganese orthoborate and copper metaborate; borate salts of Group 2B metals of the periodic table such as zinc metaborate and cadmium metaborate. Of these, metaborate is preferred.

Condensed borate salts include alkaline earth metal borates such as trimagnesium tetraborate and calcium pyroborate; transition metal borates such as manganese tetraborate and nickel diborate; periodic tables such as zinc tetraborate and cadmium tetraborate Examples thereof include borate salts of Group 2B metals.
Examples of the basic borate metal salt include basic borate salts of Group 2B metals of the periodic table such as basic zinc borate and basic cadmium borate. Further, hydrogen borates corresponding to these borates (for example, manganese orthoborate) can also be used.

As the metal borate (D) used in the present invention, an alkaline earth metal or a salt of a group 2B metal of the periodic table, for example, zinc borate or calcium borate is preferably used. The zinc borate compounds, such as zinc borate (2ZnO · _3B 2 _{O 3)} and zinc borate · 3.5 hydrate _{(2ZnO · 3B 2 O 3 ·} 3.5H 2 O) is contained, the calcium borate compound Calcium borate anhydrous (2CaO · 3B ₂ O ₃ ) and the like are included. As calcium borates, colemanite (an inorganic compound mainly composed of calcium borate, which is usually a hydrate represented by the chemical formula 2CaO · 3B ₂ O ₃ · 5H ₂ O) may be used.
Among these zinc borates and calcium borates, hydrates are preferable. Of these, zinc borates are preferred.

Among the above, the (D) boric acid metal salt preferably has a content of alkali metal and / or alkaline earth metal in the boric acid metal salt of 2,000 ppm by mass or less from the viewpoint of residence heat stability. Examples of the alkali metal and alkaline earth metal include K, Na, Ca, Mg, etc. Among them, those having a K and / or Ca content of 2,000 ppm by mass or less are preferable. More preferably, it is 1,500 ppm by mass or less, more preferably 1,000 ppm by mass or less, and particularly preferably 800 ppm by mass or less.
The content of alkali metal and / or alkaline earth metal in the borate metal salt can be measured by fluorescent X-ray analysis.

  The (D) metal borate used in the production of the polybutylene terephthalate resin composition preferably has an average particle size of 4 μm or more, more preferably 6 μm or more, and even more preferably 8 μm or more. . The upper limit of the average particle diameter is preferably 30 μm, more preferably 20 μm, and still more preferably 15 μm. (D) When the average particle diameter of the boric acid metal salt is less than 4 μm, the feedability during melt-kneading deteriorates or the dispersion state of the resulting resin composition deteriorates, and the combustibility also tends to deteriorate. This is not preferable. On the other hand, when the average particle diameter exceeds 30 μm, the mechanical properties are deteriorated and the surface appearance may be remarkably impaired. In addition, the average particle diameter of (D) metal borate salt means the median diameter (D50) measured by a laser diffraction method.

  Further, (D) a metal salt of boric acid that has been surface-treated with a surface treatment agent such as a silane coupling agent may be used. As the surface treatment agent, any conventionally known one can be used. Specifically, examples of the silane coupling agent include surface treatment agents such as aminosilane, epoxysilane, allylsilane, and vinylsilane.

  Of these, aminosilane-based surface treatment agents are preferred. Specific examples of the aminosilane coupling agent include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ- (2-aminoethyl) aminopropyltrimethoxysilane. .

  (D) As the surface treatment agent for the boric acid metal salt, as long as the effects of the present invention are not impaired, the surface treatment agent such as the silane coupling agent may include other components such as an epoxy resin, A urethane resin, an acrylic resin, an antistatic agent, a lubricant, a water repellent, and the like may be included.

  As a surface treatment method using such a surface treatment agent, surface treatment with a surface treatment agent may be performed in advance, or when preparing the polybutylene terephthalate resin composition of the present invention, the untreated metal borate is Separately, a surface treatment agent can be added for surface treatment.

  The content of the (D) boric acid metal salt is preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the (A) polybutylene terephthalate resin as described above, and more preferably 0.5 parts by mass or more. 7 parts by mass or less is more preferable, and 5 parts by mass or less is more preferable.

[Stabilizer]
It is preferable that the polybutylene terephthalate-based resin composition of the present invention further contains a stabilizer because it has effects of improving thermal stability and preventing deterioration of mechanical strength, transparency, and hue. As the stabilizer, a phosphorus stabilizer and a phenol stabilizer are preferable.
Examples of the phosphorus stabilizer include phosphorous acid, phosphoric acid, phosphite ester, phosphate ester, etc. Among them, phosphite and phosphonite are preferable.

  Examples of the phosphite include triphenyl phosphite, tris (nonylphenyl) phosphite, dilauryl hydrogen phosphite, triethyl phosphite, tridecyl phosphite, tris (2-ethylhexyl) phosphite, tris (tridecyl) phosphite. Phyto, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono (tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, water Bisphenol A phenol phosphite polymer, diphenyl hydrogen phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butyl) Ruphenyldi (tridecyl) phosphite), tetra (tridecyl) 4,4'-isopropylidene diphenyldiphosphite, bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, dilaurylpentaerythritol diphosphite Phosphite, distearyl pentaerythritol diphosphite, tris (4-tert-butylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, hydrogenated bisphenol A pentaerythritol phosphite polymer, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite 2,2'-methylenebis (4,6-di -tert- butylphenyl) octyl phosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite and the like.

  Examples of phosphonites include tetrakis (2,4-di-iso-propylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,4-di-n-butylphenyl) -4,4′-biphenyl. Range phosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,3'-biphenylene diphospho Knight, tetrakis (2,4-di-tert-butylphenyl) -3,3'-biphenylenediphosphonite, tetrakis (2,6-di-iso-propylphenyl) -4,4'-biphenylenediphosphonite, Tetrakis (2,6-di-n-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,6- -Tert-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,3'-biphenylenediphosphonite, and tetrakis (2,6-di-) tert-butylphenyl) -3,3′-biphenylenediphosphonite.

Examples of the phosphate include methyl acid phosphate, ethyl acid phosphate, propyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, butoxyethyl acid phosphate, octyl acid phosphate, 2-ethylhexyl acid phosphate, decyl acid phosphate, and lauryl acid phosphate. , Stearyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, phenyl acid phosphate, nonyl phenyl acid phosphate, cyclohexyl acid phosphate, phenoxyethyl acid phosphate, alkoxy polyethylene glycol acid phosphate, bisphenol A acid phosphate , Dimethyl acid phosphate, diethyl acid phosphate, dipropyl acid phosphate, diisopropyl acid phosphate, dibutyl acid phosphate, dioctyl acid phosphate, di-2-ethylhexyl acid phosphate, dioctyl acid phosphate, dilauryl acid phosphate, distearyl acid phosphate, Acid phosphate, bisnonylphenyl acid phosphate, etc. are mentioned.
One type of phosphorous stabilizer may be contained, or two or more types may be contained in any combination and ratio.

  Specific examples of the phenol-based stabilizer include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl- 4-hydroxyphenyl) propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N′-hexane-1,6-diylbis [3- (3 5-di-tert-butyl-4-hydroxyphenyl) propionamide], 2,4-dimethyl-6- (1-methylpentadecyl) phenol, diethyl [[3,5-bis (1,1-dimethylethyl)- 4-hydroxyphenyl] methyl] phosphoate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert- Til-a, a ′, a ″-(mesitylene-2,4,6-triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, ethylenebis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate], hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3 5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,6-di-tert -Butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol and the like.

Among them, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate preferable.
In addition, 1 type may contain the phenol type stabilizer, and 2 or more types may contain it by arbitrary combinations and a ratio.

  The content of the stabilizer is usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, and usually 1.5 parts by mass or less, relative to 100 parts by mass of the (A) polybutylene terephthalate resin. Preferably it is 1 mass part or less. If the amount is less than 0.001 part by mass, the effect as a stabilizer is insufficient, and molecular weight reduction and hue deterioration during molding are likely to occur. Deterioration tends to occur more easily.

[Release agent]
The polybutylene terephthalate resin composition of the present invention preferably further contains a release agent. As the release agent, known release agents usually used for polyester resins can be used. Among them, polyolefin compounds, fatty acid ester compounds, and silicone compounds are selected from the viewpoint of excellent release properties. One or more release agents are preferred.

  Examples of the polyolefin compound include compounds selected from paraffin wax and polyethylene wax. Among them, those having a mass average molecular weight of 700 to 10,000, more preferably 900 to 8,000 are preferable.

  Examples of the fatty acid ester compounds include fatty acid esters such as glycerin fatty acid esters and sorbitan fatty acid esters, and partially saponified products thereof. Among them, the fatty acid ester compounds are composed of fatty acids having 11 to 28 carbon atoms, preferably 17 to 21 carbon atoms. Preferred are mono- or di-fatty acid esters. Specifically, glycerol monostearate, glycerol monobehenate, glycerol dibehenate, glycerol-12-hydroxy monostearate, sorbitan monobehenate, etc. are mentioned.

  Moreover, as a silicone type compound, the compound modified | denatured from points, such as compatibility with polybutylene terephthalate resin and polyethylene terephthalate resin, is preferable. Examples of the modified silicone oil include silicone oil in which an organic group is introduced into the side chain of polysiloxane, and silicone oil in which an organic group is introduced into both ends and / or one end of polysiloxane. Examples of the organic group to be introduced include an epoxy group, an amino group, a carboxyl group, a carbinol group, a methacryl group, a mercapto group, and a phenol group, and preferably an epoxy group. As the modified silicone oil, a silicone oil in which an epoxy group is introduced into the side chain of polysiloxane is particularly preferable.

  It is preferable that content of a mold release agent is 0.05-2 mass parts with respect to 100 mass parts of (A) polybutylene terephthalate resin. If the amount is less than 0.05 parts by mass, the surface property tends to decrease due to defective mold release at the time of melt molding. On the other hand, if it exceeds 2 parts by mass, the kneading workability of the resin composition decreases, and molding is also performed. The surface of the product may be cloudy. The content of the release agent is preferably 0.07 to 1.5 parts by mass, more preferably 0.1 to 1.0 parts by mass.

[Glass fiber]
The polybutylene terephthalate resin composition of the present invention preferably further contains a reinforcing filler, and a conventional inorganic filler for plastics can be used as the reinforcing filler. Preferably, fibrous fillers such as glass fiber, carbon fiber, basalt fiber, wollastonite and potassium titanate fiber can be used.
Among these, glass fibers are preferably used from the viewpoint of mechanical strength, rigidity, and heat resistance. Glass flakes are not preferred because they tend to reduce the impact resistance. Therefore, it is preferable that the polybutylene terephthalate resin composition of the present invention does not contain glass flakes, and even when it is contained, it is 7 parts by mass or less with respect to 100 parts by mass of (A) polybutylene terephthalate resin. More preferably, it is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and particularly preferably less than 2 parts by mass.

The glass fiber is preferably a glass fiber having a fiber length of 0.3 to 10 mm, an average fiber diameter of 3 to 20 μm, and a circular cross section. By using such a glass fiber having a circular cross section, the mechanical strength, in particular, the elastic modulus and the impact resistance can be improved to a high level.
The average fiber diameter of the glass fiber having a circular cross section is more preferably 5 μm or more, further preferably 7 μm or more, more preferably 18 μm or less, and further preferably 15 μm or less. Further, the fiber length is more preferably 0.5 mm or more, further preferably 1 mm or more, more preferably 8 mm or less, and further preferably 5 mm or less.

  Here, “the cross section is circular” of the glass fiber having a circular cross section means that the cross section perpendicular to the length direction of the glass fiber is substantially circular, specifically, the major axis of the cross section perpendicular to the length direction. The average value of the ratio of the diameter to the minor axis (also referred to as flatness) is 1 to 1.5: 1, preferably 1 to 1.4: 1, more preferably 1 to 1.3: 1, and still more preferably. 1 to 1.2: 1, particularly preferably 1 to 1.1: 1.

It is more preferable to use a glass fiber that has been surface-treated with a surface treatment agent such as a coupling agent. The glass fiber to which the surface treatment agent is attached is preferable because it is excellent in durability, heat and humidity resistance, hydrolysis resistance, and heat shock resistance.
As the surface treatment agent, any conventionally known one can be used. Specifically, for example, silane coupling agents such as amino silane, epoxy silane, allyl silane, and vinyl silane are preferable.
Among these, aminosilane-based surface treatment agents are preferable, and specifically, for example, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ- (2-aminoethyl) aminopropyltrimethoxysilane are preferable. Take as an example.

Moreover, as a surface treating agent, epoxy resins, such as a novolac type, a bisphenol A type epoxy resin, etc. are mentioned preferably. Among these, novolac type epoxy resins are preferable.
The silane-based surface treatment agent and the epoxy resin may be used alone or in combination, and it is also preferable to use both in combination.

  It is preferable that content of glass fiber is 0-100 mass parts with respect to 100 mass parts of (A) polybutylene terephthalate resin. The more preferable content of the glass fiber is 5 to 90 parts by mass, more preferably 15 to 80 parts by mass, further preferably 30 to 80 parts by mass, and particularly 40 to 70 parts by mass.

[Carbon black]
The polybutylene terephthalate-based resin composition of the present invention preferably contains carbon black for the purpose of making the molded product have a desired color tone such as black.
There are no restrictions on the type, raw material type, and manufacturing method of carbon black, and any of furnace black, channel black, acetylene black, ketjen black, and the like can be used. The number average particle diameter is not particularly limited, but is preferably about 5 to 60 nm.

  The content of carbon black is preferably 0.1 to 2.0 parts by mass, and more preferably 0.3 to 1.0 part by mass with respect to 100 parts by mass of (A) polybutylene terephthalate resin.

Carbon black is preferably blended in advance as a master batch containing carbon black at a high concentration in order to improve the handling property during the production of the resin composition and the uniform dispersibility in the resin composition. In this case, the resin used for the carbon black masterbatch may be (A) component polybutylene terephthalate resin, resin (A) other than component, polycarbonate resin, polyethylene terephthalate resin, styrenic resin, polyethylene It may be a resin or the like. From the viewpoint of easy dispersion of high-concentration carbon black and easy formation of a masterbatch, it is preferable to use (A) polybutylene terephthalate resin.
The carbon black concentration of the carbon black masterbatch is usually about 10 to 50% by mass.

[Fluorine-containing resin]
The polybutylene terephthalate resin composition of the present invention preferably contains a dripping preventive agent for improving combustibility. As the dripping preventive agent, a fluorine-containing resin, typically a polytetrafluoroethylene resin (PTFE) is used. ).
However, it has been found that when a fluorine-containing resin is contained as a flame retardant aid in order to improve flame retardancy, the thin molded article tends to be inferior in dimensional stability, such as warping. And since this problem of dimensional stability tends to become prominent when the content of the fluorine-containing resin increases, in the present invention, it is preferable not to contain a large amount of the fluorine-containing resin. Is preferably not more than 1% by mass, more preferably 0.5% by mass or more, especially 0.3% by mass or more, especially 0.1% by mass or more, especially 0.05% by mass or more. It is preferable not to contain in this quantity.
In the present invention, substantially not containing a fluorine-containing resin means that the polybutylene terephthalate-based resin composition does not contain a fluorine-containing resin in an amount exceeding 1% by mass, more preferably. Means 0.5% by mass or more, especially 0.3% by mass or more, especially 0.1% by mass or more, and especially 0.05% by mass or more.

[Other ingredients]
The polybutylene terephthalate resin composition of the present invention may further contain various additives as long as the effects of the present invention are not impaired. Examples of such additives include ultraviolet absorbers, dyes and pigments, fluorescent whitening agents, antistatic agents, antifogging agents, lubricants, antiblocking agents, fluidity improvers, plasticizers, dispersants, antibacterial agents, and the like. It is done.

In addition, the polybutylene terephthalate resin composition in the present invention can contain a thermoplastic resin other than the above-described resins within a range that does not impair the effects of the present invention.
As other thermoplastic resins, specifically, for example, polyethylene terephthalate resin, polycarbonate resin, polyacetal resin, polyamide resin, polyphenylene oxide resin, polystyrene resin, polyphenylene sulfide ethylene resin, polysulfone resin, polyether sulfone resin, Examples include polyetherimide resins, polyether ketone resins, and polyolefin resins.

[Maximum calorific value and peak temperature from combustion calorimetry]
The polybutylene terephthalate resin composition of the present invention is characterized in that the maximum calorific value obtained from combustion calorimetry is 240 W / g or less and the peak temperature at the maximum exotherm is 420 ° C. or less.

Combustion calorimetry is a thermal analysis technology that identifies the combustion characteristics of combustible materials represented by resin, controls the heat generation of minute samples, performs thermal oxidation of gas generated from samples, and tracks oxygen consumption This is an analytical method for measuring the calorific value.
In the present invention, the specific measurement method is as follows.
That is, in accordance with ASTM D7309, a heat generation amount (heat release rate, also referred to as a heat generation rate, a heat generation rate or a heat release rate, hereinafter referred to as “HRR”) is measured. From the graph of temperature and calorific value, it is defined as the temperature at which the maximum calorific value is shown (hereinafter sometimes abbreviated as “TmaxHRR”). As a device, a microscale combustion calorimeter (hereinafter sometimes abbreviated as “MCC”) is used and measured under an atmosphere of oxygen: 20% and nitrogen: 80% in accordance with ASTM D7309. Is done.

  FIG. 1 is a graph showing the relationship between the calorific value (W / g) obtained from combustion calorimetry and the exothermic temperature (° C.). The horizontal axis is the temperature when the temperature is raised (° C.), the vertical axis is the calorific value (HRR), the maximum peak point of the graph shows the maximum calorific value (maxHRR), and the temperature at that time is the maximum calorific value The peak temperature (TmaxHRR).

  When (A) polybutylene terephthalate resin burns, (B) brominated flame retardant reacts with (C) antimony trioxide, and the reaction product is an active radical generated in (A) polybutylene terephthalate resin. It is considered that the flame retardancy is improved because it exhibits the effect of capturing oxygen and blocking oxygen in the gas phase. The (D) borate metal salt preferably contained is also considered to exert the flame retardant aid effect by the same mechanism as (C) antimony trioxide. The polybutylene terephthalate resin composition of the present invention is decomposed and generated during combustion because the maximum calorific value (maxHRR) is 240 W / g or less and the peak temperature (TmaxHRR) at the maximum exotherm is 420 ° C. or less. The amount of active radicals can be reduced, the continuity of combustion can be suppressed, and the temperature at which the maximum calorific value is generated can be lowered. Even if dripping occurs during combustion, the combustion temperature is relatively quickly when leaving the flame. Since it is easy to fall, it is presumed that dripping and ignition can be suppressed, and the resin composition of the present invention can further improve the flame retardancy.

  The maximum calorific value (maxHRR) is preferably 235 W / g or less, more preferably 225 W / g or less, further preferably 220 W / g or less, particularly preferably 215 W / g or less, and its lower limit is usually 160 W / g. That's it. The peak temperature (TmaxHRR) at the maximum exotherm is preferably 418 ° C. or lower, more preferably 415 ° C. or lower, further preferably 412 ° C. or lower, and the lower limit is usually preferably 380 ° C. or higher.

[UL94 vertical combustion test]
The polybutylene terephthalate resin composition of the present invention has a high flame retardancy of V-0 in a thin wall having a thickness of 0.35 mm by UL94 vertical combustion test. And, as shown in the examples, it is at V-0 level, and the UL94 combustion test piece (0.35 mm thickness) exhibits a high degree of flame retardancy such that the flame is easily extinguished upon drip. Can do.

[Charpy with notch]
The resin composition of the present invention has a notch Charpy impact strength measured at 23 ° C. according to ISO 179 of preferably 7 kJ / m ² or more. The polybutylene terephthalate-based resin composition of the present invention has high flame retardancy by having the above-described maxHRR and TmaxHRR to suppress the content of (B) brominated flame retardant as much as possible. It becomes possible to maintain impact resistance. Charpy impact strength is more preferably 8 kJ / ^{m 2} or more, more preferably 8.5kJ / ^{m 2} or more, and particularly preferably at 8.8kJ / ^{m 2} or more.

[Method for Producing Resin Composition]
As a method for producing the polybutylene terephthalate resin composition of the present invention, the respective components and various additives to be added as desired are mixed well, and then melt-kneaded in a single-screw or twin-screw extruder. Moreover, it is also possible to prepare the resin composition of the present invention by mixing each component in advance or by mixing only a part of the components in advance and supplying them to an extruder using a feeder and melt-kneading them. Furthermore, a masterbatch is prepared by melting and kneading a part of the polybutylene terephthalate resin with a part of the other ingredients, and then blending the remaining polybutylene terephthalate resin and other ingredients to the melt. You may knead. In addition, when using fibrous things, such as glass fiber, as a reinforcing filler, it is also preferable to supply from the side feeder in the middle of the cylinder of an extruder.

  In addition, as described above, (C) antimony trioxide that has been previously masterbatched is used in terms of variations in thermal stability, flame retardancy, and impact resistance during melt kneading and molding. ,preferable. The method of masterbatching is not particularly limited, and examples thereof include a method of melt-kneading a thermoplastic resin, preferably a polybutylene terephthalate resin and antimony trioxide, with a kneader such as a twin screw extruder. In addition, various additives such as stabilizers can be blended as necessary when forming a masterbatch.

  When (C) antimony trioxide is blended as a master batch, (A) polybutylene terephthalate resin, (B) brominated flame retardant and (C) master batch of antimony trioxide, and other additives as required Is fed to a kneader such as an extruder. As the extruder, a single screw or twin screw extruder provided with a die nozzle is used.

At this time, the antimony trioxide masterbatch is preferably supplied to the extruder from a dedicated feeder provided separately from other raw materials. Antimony trioxide masterbatch is not mixed with other flame retardants and additives and supplied from the same feeder, but from an independent dedicated feeder, classification is suppressed, flame resistance and impact resistance Is preferable from the standpoint of better and less variation.
When supplying the antimony trioxide master batch from a dedicated feeder, it may be fed simultaneously to other raw materials from the dedicated feeder to the hopper of the extruder, or may be fed in the middle of the extruder. When feeding in the middle of an extruder, it is preferable to feed to the hopper side rather than a kneading zone.

  Further, in the present invention, it is preferable to blend (D) a metal borate, whereby the feed property at the time of melt-kneading is improved, and the dispersion state of the resulting resin composition is improved, as described above. It becomes easy to achieve maxHRR and TmaxHRR. In particular, (D) the boric acid metal salt should be blended in advance with a powdery component, for example, a powdery additive component such as powdery (B) brominated flame retardant or (C) antimony trioxide. Is preferred. Any method may be used for blending, and each component may be blended using various blenders, mixers and the like. By using such a pre-blend, the feed property at the time of melt-kneading can be further improved.

When feeding each of the above components to the extruder, it is preferable to feed a powdery component and a non-powdered component such as a pellet from separate feeders. In the case of coarse, it is preferable to feed it independently from a feeder other than the feeder for powder and pellet, but it is pre-blended with the powder component and fed from the feeder for powder. Also good. Moreover, when using (C) antimony trioxide as a masterbatch, it is preferable from a viewpoint of classification suppression to feed a polybutylene terephthalate resin pellet and an antimony trioxide masterbatch pellet with large specific gravity from a separate feeder.
More specifically, (i) polybutylene terephthalate resin pellets, (ii) antimony trioxide masterbatch pellets, (iii) (D) boric acid metal salt, powdered (B) bromine-based flame retardant and as required More preferably, the pre-blends of other powdered additive components to be blended are fed from separate feeders. Moreover, it is preferable that the fibrous reinforcing filler such as glass fiber is side-fed from the middle of the extruder. In the present invention, (iii) the presence of (D) metal borate in the powdery pre-blend product tends to improve the fluidity of the powdery component and improve the feedability.

After supplying to the extruder, the mixture is melt-kneaded, extruded from the die nozzle to form a strand, and then cooled and cut to produce a molded body (pellet) of the thermoplastic resin composition.
At this time, it is preferable to use a twin screw extruder as the melt kneader. Especially, it is preferable that L / D which is a ratio of the screw length L (mm) to the diameter D (mm) of the screw satisfies the relationship of 10 <(L / D) <150, and 15 <(L / D) It is more preferable to satisfy <100. If the ratio is 10 or less, the polybutylene terephthalate resin, antimony trioxide and brominated flame retardant are difficult to finely disperse. Conversely, if the ratio is 150 or more, the thermal degradation of the brominated flame retardant becomes significant, and gas problems due to free compounds occur. Or the mechanical strength of the resin composition tends to decrease due to thermal degradation.

  Moreover, it is preferable that the melting temperature of the resin composition at the time of melt-kneading is 180-350 degreeC, and it is more preferable that it is 190-320 degreeC. When the melting temperature is less than 180 ° C., melting is insufficient and unmelted gel tends to occur frequently. Conversely, when it exceeds 350 ° C., the resin composition is thermally deteriorated and easily colored, which is not preferable.

  It is preferable that the screw rotation speed at the time of melt kneading is 50 to 1,500 rpm. If the screw rotation speed is less than 50 rpm, the antimony compound tends to hardly disperse, and conversely if it exceeds 1,500 rpm, antimony trioxide tends to aggregate and not disperse finely, which is not preferable. Further, the discharge amount is preferably 5 to 5,000 kg / hr, more preferably 10 to 3,000 kg / hr. When the discharge amount is less than 5 kg / hr, the dispersibility of antimony trioxide tends to decrease, and even when it exceeds 5,000 kg / hr, the dispersibility tends to decrease due to reaggregation of antimony trioxide. Absent.

[Preferred adjustment method of maxHRR and TmaxHRR]
The polybutylene terephthalate-based resin composition of the present invention is preferably produced by a melt-kneading method using a melt-kneader such as an extruder. By simply kneading, it is difficult to stably maintain the maximum temperature and Charpy impact strength of the calorific value specified in the present invention, and it is recommended to knead by a special method.
Below, the preferable manufacturing method for that is demonstrated.

(A) Polybutylene terephthalate resin, (B) Brominated flame retardant and (C) Antimony trioxide, more preferably (D) Boric acid metal salt is mixed at a predetermined ratio, and then uniaxial or biaxial in which a die nozzle is provided Then, the mixture is melt-kneaded, extruded from the die nozzle to form a strand, and then cut to produce pellets.
At this time, it is preferable to use a twin screw extruder as the melt kneader. Especially, it is preferable that L / D which is the ratio of the screw length L (mm) to the diameter D (mm) of the screw satisfies the relationship of 15 <(L / D) <100, and 20 <(L / D) It is more preferable to satisfy <80.
The shape of the die nozzle is not particularly limited, but in terms of pellet shape, a circular nozzle having a diameter of 1 to 11 mm is preferable, and a circular nozzle having a diameter of 2 to 8 mm is more preferable.

  Further, when the raw materials are supplied to a melt-kneader such as an extruder, (B) a brominated flame retardant and (C) antimony trioxide, more preferably (D) zinc borate are blended in advance before the melt-kneading, The preliminary blend is preferably supplied to a melt kneader such as an extruder from a feeder provided separately from (A) the polybutylene terephthalate resin.

Moreover, it is preferable that the melting temperature of the resin composition at the time of melt-kneading is 200-340 degreeC, and it is more preferable that it is 220-320 degreeC. When the melting temperature is less than 220 ° C., melting is insufficient and unmelted gel tends to occur frequently. Conversely, when the melting temperature exceeds 340 ° C., the resin composition is thermally deteriorated and easily colored.
The screw rotation speed during melt kneading is preferably 50 to 1,200 rpm, and more preferably 80 to 1,000 rpm. The discharge rate is preferably 10 to 2,000 kg / hr, and more preferably 15 to 1,800 kg / hr.

  The resin composition extruded in a strand form from the die nozzle is cut into a pellet shape by a pelletizer or the like. In the present invention, the surface temperature of the strand during cutting is preferably 35 to 150 ° C., more preferably 40 to 135. It is preferable to cool the strands at a temperature of 50 ° C., more preferably 45 to 110 ° C., particularly preferably 50 to 100 ° C. Usually, it is cooled by a method such as air cooling or water cooling, but water cooling is preferable in terms of cooling efficiency. In such water cooling, the strand may be cooled in a water tank containing water, and a desired strand surface temperature can be obtained by adjusting the water temperature and the cooling time. The shape of the pellets thus produced is preferably 1 to 10 mm in diameter, more preferably 2 to 8 mm, more preferably 3 to 6 mm, and more preferably 1 to 12 mm in length in the case of a columnar shape. Is 2 to 8 mm, more preferably 3 to 6 mm.

  In the present invention, the polybutylene terephthalate resin composition defined in the present invention can be produced by applying the above preferable conditions alone or in combination. However, the method is not limited to this method, and other methods may be used as long as the above-described maximum heat generation amount and the peak temperature at the maximum heat generation can be obtained.

The polybutylene terephthalate resin composition of the present invention is usually molded into an arbitrary shape and used as a molded body. There is no restriction | limiting in the shape, pattern, color, dimension, etc. of this molded object, What is necessary is just to set arbitrarily according to the use of the molded object.
The manufacturing method of a molded object is not specifically limited, The molding method generally employ | adopted about the polybutylene terephthalate type-resin composition can be employ | adopted arbitrarily. For example, injection molding method, ultra-high speed injection molding method, injection compression molding method, two-color molding method, hollow molding method such as gas assist, molding method using heat insulating mold, rapid heating mold were used. Molding method, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, laminate molding method, press molding method, Examples thereof include a blow molding method, and an injection molding method is particularly preferable.

Since the polybutylene terephthalate resin composition of the present invention has a good balance between high flame retardancy and impact resistance, it can be widely used in various applications, and can be used as electrical equipment, electronic equipment or insulating parts thereof. Particularly preferred.
Preferred insulating parts include connector parts, relay parts, switch parts, breaker parts, electromagnetic switch parts, terminal block parts, and the like.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to the following examples.
In the following description, “parts” means “parts by mass” based on mass standards unless otherwise specified.
In the following Examples and Comparative Examples, the components used are as shown in Table 1 below.

(Examples 1-8)
Among the components described in Table 1, the components (B1) to (B3), (C1), (C2), (D), (E) and (F) are mixed in the proportions described in Table 3 (all parts by mass). ) In advance with a blender (blend 1). In addition, the components (A1), (A2) and (H) were also blended in advance with a blender at a ratio (all parts by mass) shown in Table 3 (blend product 2).
The obtained blend 1 and blend 2 are fed from two independent feeders to the hopper so that the ratio (all parts by mass) shown in Table 3 is obtained, and this is fed to a 30 mm vent type 2 (G1) Glass fiber is supplied from the seventh side feeder from the hopper, and the barrel set temperature C1 to C15 of the extruder is 265. Using a screw extruder (manufactured by Nippon Steel Works, twin screw extruder “TEX30α”) C., melted and kneaded under the conditions of 260.degree. C., discharge 60 kg / hr, screw rotation speed 290 rpm, number of nozzles 5 holes (circular (.phi.4 mm), length 1.5 cm), and extruded into strands. The strand temperature immediately after extrusion was 280 ° C.
The extruded strand was introduced into a water bath whose temperature was adjusted to a range of 40 to 80 ° C. and cooled. The strand surface temperature was cooled to 110 ° C. at a temperature measured with an infrared thermometer, inserted into a pelletizer, and cut to obtain pellets of a polybutylene terephthalate resin composition.
Using a microscale combustion calorimeter manufactured by Covmark, Inc. in the United States, in accordance with ASTM D7309, measure the calorific value as the temperature rises in an atmosphere of oxygen: 20% and nitrogen: 80%. (Unit: W / g) and peak temperature (unit: ° C.) at maximum exotherm were measured.

(Comparative Examples 1-5)
Among the components shown in Table 1, the components (B1) to (B3), (C1), (D), (E) and (F) are blended in advance in the proportions shown in Table 4 (all parts by mass). (Blend 1). In addition, the components (A1), (A2) and (H) were also blended in advance with a blender at a ratio (all parts by mass) shown in Table 4 (blend product 2).
The obtained blend 1 and blend 2 are fed from two independent feeders to the hopper so that the ratio (all parts by mass) shown in Table 4 is obtained. Using a screw extruder (manufactured by Nippon Steel Co., Ltd., twin screw extruder “TEX30α”), (G1) glass fiber or (G2) glass flake is supplied from the seventh side feeder from the hopper, and the barrel setting of the extruder Melted and kneaded under the conditions of temperatures C1 to C15 of 260 ° C., die of 255 ° C., discharge of 80 kg / hr, screw rotation speed of 200 rpm, number of nozzles of 5 holes (circular (φ4 mm), length of 1.5 cm), and extruded into strands did. The strand temperature immediately after extrusion was 270 ° C.
The extruded strand was introduced into a water bath whose temperature was adjusted to a range of 40 to 80 ° C. and cooled. The strand surface temperature was cooled to 110 ° C. at a temperature measured with an infrared thermometer, inserted into a pelletizer, and cut to obtain pellets of a polybutylene terephthalate resin composition.
In the same manner as in Example 1, the maximum value of heat generation (unit: W / g) and the peak temperature at the time of maximum heat generation (unit: ° C.) were measured.

<Evaluation method>
The evaluation method is as follows.

  The resin composition pellets obtained above are dried at 120 ° C. for 5 hours, and then ISO molded under the conditions of a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. with an injection molding machine (“NEX80” manufactured by Nissei Plastic Industry Co., Ltd.). Multipurpose test pieces (4 mm thickness) and UL94 combustion test pieces (0.35 mm thickness) were injection molded.

Flammability (UL94) test:
In accordance with the method of Subject 94 (UL94) of Underwriters Laboratories, flame resistance was tested using five combustion test pieces (0.35 mm thickness), and V-0, V-1 and V-2 Classified.
UL94 is a method for evaluating the flame retardancy from the afterflame time and drip properties after the flame of a burner is indirect flame for 10 seconds on a test piece held vertically. V-0, V-1 and V-2 In order to have flame retardancy, it is necessary to satisfy the criteria shown in Table 2 below.

Here, the afterflame time is the length of time for which the flammable combustion of the test piece is continued after the ignition source is moved away. The cotton ignition by the drip is determined by whether or not the absorbent cotton for labeling, which is about 300 mm below the lower end of the test piece, is ignited by a drip from the test piece.

Evaluation of the number of flames maintained during drip:
Moreover, the number which maintained the flame to the vicinity of absorbent cotton at the time of drip was evaluated.
That is, in the test of 5 pieces, the number of pieces (pieces / 5 pieces) that maintained the flame to the vicinity of the absorbent cotton during the drip was counted. In this case, “5/5” means that, while 5 were tested, the flame was maintained close to the absorbent cotton at the time of drip, and V-0 evaluation was close to V-2. . “0/5” refers to the number of flames that quickly disappeared during the drip test when 5 were tested, which means a stable V-0 evaluation.

Notched Charpy impact strength:
A 4.0 mm thick notched test piece was prepared from the ISO multipurpose test piece (4.0 mm thick), and the notched Charpy impact strength (unit: kJ / m ² ) was measured in accordance with the ISO 179 standard.
The above evaluation results are shown in Tables 3 and 4 below.

  Since the polybutylene terephthalate resin composition of the present invention is excellent in high flame retardancy and impact resistance, it can be widely used in various applications, and particularly as an insulating part of electrical equipment, electronic equipment or the like. It can be suitably used.

Claims (12)

  (A) 100 parts by mass of polybutylene terephthalate resin, containing (B) 5-50 parts by mass of brominated flame retardant, (C) 3-15 parts by mass of antimony trioxide, and measuring calorific value in accordance with ASTM D7309 The maximum calorific value obtained from the above is 240 W / g or less, the peak temperature at the maximum exotherm is 420 ° C. or less, and the flame retardancy in the UL94 vertical combustion test at a thickness of 0.35 mm is V-0. A polybutylene terephthalate-based resin composition.   The polybutylene terephthalate resin composition according to claim 1, wherein a peak temperature at the time of the maximum heat generation is 412 ° C. or less. The polybutylene terephthalate resin composition according to claim 1 or 2, which has a notched Charpy impact strength of 7 kJ / m ² or more measured at 23 ° C according to ISO 179.   The polybutylene terephthalate resin according to any one of claims 1 to 3, further comprising (D) 0.3 to 10 parts by mass of (D) a boric acid metal salt with respect to 100 parts by mass of (A) polybutylene terephthalate resin. Composition.   (D) The polybutylene terephthalate resin composition according to claim 4, wherein the metal borate is a zinc borate.   The polybutylene terephthalate resin composition according to any one of claims 1 to 5, wherein (B) the brominated flame retardant is a polybrominated benzyl (meth) acrylate flame retardant.   (C) The polybutylene terephthalate resin composition according to any one of claims 1 to 6, wherein antimony trioxide is blended as a master batch.   The polybutylene terephthalate resin composition according to any one of claims 1 to 7, wherein (D) the content of alkali metal and alkaline earth metal in the borate metal salt is 2,000 mass ppm or less.   The polybutylene terephthalate resin composition according to any one of claims 1 to 8, further comprising glass fibers having a fiber length of 0.3 to 10 mm and an average fiber diameter of 3 to 20 µm and a circular cross section. .   A molded article of the polybutylene terephthalate resin composition according to any one of claims 1 to 9.   The molded body according to claim 10, wherein the molded body is an electric / electronic device component.   The molded body according to claim 10 or 11, wherein the molded body is any one selected from the group consisting of a connector part, a relay part, a switch part, a breaker part, an electromagnetic switch part, and a terminal block part.