JP7174602B2 - polyester resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyester resin composition, and more particularly to a polyester resin composition having excellent strength and impact resistance, as well as excellent heat shock resistance, flame retardancy and moldability.

Polyalkylene terephthalate resins such as polyethylene terephthalate resin and polybutylene terephthalate resin are excellent in mechanical properties, electrical properties, other physical and chemical properties, etc., and are also excellent in workability. It is widely used as a material for manufacturing automobile parts, electrical and electronic equipment parts, household appliance parts, and other general industrial products.

However, the polyalkylene terephthalate resin has the disadvantage that it retains its original physical properties when exposed alternately to high-temperature and low-temperature environments, that is, it is inferior in resistance to heat shock (heat shock resistance). have. For example, in the case of a molded product with a metal member inserted, such as a motor stator core sealed product, the difference in thermal expansion/contraction rate due to temperature changes between the polyalkylene terephthalate resin and the internal metal member may affect the environmental temperature during use. The change may cause the molding to crack. For this reason, the applications and shapes of molded products are considerably restricted.

Furthermore, when reinforcing fillers such as glass fibers are blended with polyalkylene terephthalate resin for the purpose of improving the cracking of molded products due to changes in environmental temperature during use, the resulting molded product will expand due to the orientation of the reinforcing fillers.・Anisotropic shrinkage rate is likely to occur, and the reduction in elongation due to the addition of reinforcing fillers further increases the frequency of damage to the molded product due to temperature changes during use.

Conventionally, for the purpose of improving the heat shock resistance of moldings obtained by insert-molding metal members and the like, methods have been proposed in which thermoplastic polyester resins are blended with impact resistance modifiers. For example, Patent Document 1 proposes a method of blending an acrylic rubber, and Patent Document 2 proposes a method of blending an ethylene-glycidyl acrylate copolymer.

Further, in Patent Document 3, (A) polybutylene terephthalate resin, (B) (a) ethylene-unsaturated carboxylic acid alkyl ester copolymer portion 5 to 95% by mass, and (b) vinyl-based ( Co) 1 to 30% by mass of a graft copolymer with 95 to 5% by mass of a polymer portion (in the total composition), (C) 5 to 50% by mass of a fibrous filler having a non-circular cross section with a longitudinal cross section %, a polybutylene terephthalate resin composition has been proposed.

JP-A-63-3055 JP-A-60-219254 JP-A-2000-265046

However, in automobile parts, electric and electronic equipment parts, home appliance parts, etc., the molded products are becoming thinner and the shape of the parts is becoming more complicated as the miniaturization progresses. are required to have higher heat shock resistance, and further improvement is required. Furthermore, it is necessary to be excellent in strength, impact resistance, flame retardancy and moldability.
The object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a polyester resin composition having excellent strength and impact resistance, as well as excellent heat shock resistance, flame retardancy and moldability ( task).

As a result of intensive studies to solve the above problems, the present inventors have found that a glass fiber-containing polyalkylene terephthalate resin contains an elastomer, a brominated flame retardant, an antimony compound, and an epoxy group to achieve a glass transition. By containing a specific amount of plasticizer whose temperature is below a specific temperature, the above problems are solved, heat shock resistance is greatly improved, excellent strength and impact resistance, flame retardancy and molding are improved. The present invention was completed by discovering that the properties are excellent.
The present invention relates to the following polyester resin composition and molded article.

[1] (A) 100 parts by mass of polyalkylene terephthalate resin, (B) 5 to 150 parts by mass of glass fiber, (C) 5 to 50 parts by mass of elastomer, (D) 5 to 50 parts by mass of brominated flame retardant, (E) 1 to 20 parts by mass of an antimony compound, and (F) 1 to 10 parts by mass of a plasticizer containing an epoxy group and having a glass transition temperature of -50°C or less.
[2] (D) The polyester resin composition according to the above [1], wherein the brominated flame retardant is polybrominated benzyl (meth)acrylate.
[3] The polyester resin composition according to the above [1] or [2], wherein (C) the elastomer is a block copolymer containing a component derived from a vinyl aromatic compound.
[4] (F) The polyester resin composition according to any one of [1] to [3] above, wherein the plasticizer has an epoxy value of 1.0 meq/g or more.
[5] The polyester resin composition according to any one of [1] to [4] above, wherein (A) the polyalkylene terephthalate resin has an intrinsic viscosity of 0.50 to 1.00 dl/g.
[6] A molded article made of the polyester resin composition according to any one of [1] to [5] above. [7] The molded product according to the above [6], which is an insert-molded product with metal.

The polyester resin composition of the present invention has greatly improved heat shock resistance, excellent strength and impact resistance, flame retardancy and moldability.

FIG. 2 is a schematic diagram of a rectangular parallelepiped iron insert used for evaluation of heat shock resistance in Examples. FIG. 4 is a cross-sectional explanatory view of a mold cavity in which an insert is supported by support pins; FIG. 4 is a schematic diagram of an insert-molded product in which two weld lines are generated on traces of support pins;

The contents of the present invention will be described in detail below. In this specification, the term "~" is used to mean that the numerical values before and after it are included as the lower limit and the upper limit.

The polyester resin composition of the present invention comprises (A) 100 parts by mass of polyalkylene terephthalate resin, (B) 5 to 150 parts by mass of glass fiber, (C) 5 to 50 parts by mass of elastomer, and (D) brominated flame retardant. 5 to 50 parts by mass, (E) 1 to 20 parts by mass of an antimony compound, and (F) 1 to 10 parts by mass of a plasticizer containing an epoxy group and having a glass transition temperature of -50°C or lower. do.

[(A) Polyalkylene terephthalate resin]
The polyester resin composition of the present invention contains (A) a polyalkylene terephthalate resin. (A) Polyalkylene terephthalate resin is a polyester obtained by polycondensation of terephthalic acid as a dicarboxylic acid compound and a dihydroxy compound, and may be homopolyester or copolyester.

(A) As the dicarboxylic acid compound constituting the polyalkylene terephthalate resin, a terphthalic acid compound or an ester-forming derivative thereof is preferably used.
Aromatic dicarboxylic acids other than terephthalic acid can also be used in combination. 2'-dicarboxylic acid, biphenyl-3,3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4 ,4'-dicarboxylic acid, diphenylisopropylidene-4,4'-dicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, anthracene-2,5-dicarboxylic acid, anthracene-2, 6-dicarboxylic acid, p-terphenylene-4,4′-dicarboxylic acid, pyridine-2,5-dicarboxylic acid, etc., and these are ester-forming derivatives such as dimethyl esters in addition to free acids in the polycondensation reaction. can be used.
Among the above, isophthalic acid or its ester-forming derivative can be preferably used.

In addition, in small amounts, together with terephthalic acid and the above aromatic dicarboxylic acids, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, dodecanedioic acid, and sebacic acid, 1,2-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid Acids and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid can be used in combination of one or more.

(A) Dihydroxy compounds constituting the polyalkylene terephthalate resin include ethylene glycol, propylene glycol, butanediol, hexylene glycol, neopentyl glycol, 2-methylpropane-1,3-diol, diethylene glycol, triethylene glycol, and the like. Examples include aliphatic diols, alicyclic diols such as cyclohexane-1,4-dimethanol, and mixtures thereof. Among these, butanediol and ethylene glycol are particularly preferred.

One or more long-chain diols having a molecular weight of 400 to 6,000, ie, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, etc. may be copolymerized.
Aromatic diols such as hydroquinone, resorcinol, naphthalene diol, dihydroxydiphenyl ether, and 2,2-bis(4-hydroxyphenyl)propane can also be used.

In addition to the above bifunctional monomers, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane for introducing a branched structure, and fatty acids for molecular weight adjustment. A small amount of monofunctional compound can also be used together.

(A) The polyalkylene terephthalate resin is mainly composed of polycondensation of terephthalic acid and a diol, that is, the amount exceeding 50% by mass, preferably 70% by mass or more, more preferably 80% by mass or more of the total resin. It is preferred to use those consisting of polycondensates. Aliphatic diols are preferred as diols.

(A) The polyalkylene terephthalate resin preferably has an intrinsic viscosity of 0.5 to 1.0 dl/g. If one with an intrinsic viscosity lower than 0.5 dl/g is used, the resulting resin composition tends to have low mechanical strength. On the other hand, if it is higher than 1.0 dl/g, the flowability of the resin composition may deteriorate and the moldability may deteriorate. From the viewpoint of moldability and mechanical properties, the intrinsic viscosity is more preferably 0.6 dl/g or more, further preferably 0.65 dl/g or more, particularly preferably 0.7 dl/g or more, and more preferably is preferably 0.95 dl/g or less, more preferably 0.93 dl/g or less, particularly 0.85 dl/g or less.
In the present invention, the intrinsic viscosity of (A) the polyalkylene terephthalate resin is a value measured at 30° C. in a 1:1 (mass ratio) mixed solvent of tetrachloroethane and phenol.

(A) The terminal carboxyl group amount of the polyalkylene terephthalate resin may be selected and determined as appropriate, but is usually 60 eq/ton or less, preferably 60 eq/ton or less, and 30 eq/ton or less. is more preferred. 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 generally 3 eq/ton, preferably 5 eq/ton, more preferably generally 10 eq/ton.

The amount of terminal carboxyl groups of the (A) polyalkylene terephthalate resin is a value measured by dissolving 0.5 g of the resin in 25 ml of benzyl alcohol and titrating with a 0.01 mol/l benzyl alcohol solution of sodium hydroxide. . As a method for adjusting the amount of terminal carboxyl groups, any conventionally known method may be used, such as a method of adjusting polymerization conditions such as the raw material charge ratio during polymerization, the polymerization temperature, and a decompression method, or a method of reacting a terminal blocking agent. You can do it.

The polyalkylene terephthalate resin (A) is preferably a polyalkylene terephthalate resin in which 95 mol % or more of the acid component is terephthalic acid and 95 mol % or more of the alcohol component is an aliphatic diol. are polybutylene terephthalate resins and polyethylene terephthalate resins. The (A) polyalkylene terephthalate resin is preferably one close to homopolyester, that is, one in which 95 mol % or more of the entire resin is composed of a terephthalic acid component and a 1,4-butanediol or ethylene glycol component.
Among them, the (A) polyalkylene terephthalate resin preferably contains a polybutylene terephthalate resin as a main component, and the polybutylene terephthalate resin accounts for more than 50% by mass in the (A) polyalkylene terephthalate resin. At that time, it is also preferable to contain the polyethylene terephthalate resin in an amount of less than 50% by mass.

Polybutylene terephthalate resin is produced by melt-polymerizing a dicarboxylic acid component or ester derivative thereof containing terephthalic acid as a main component and a diol component containing 1,4-butanediol as a main component in a batch or continuous process. can do. Further, after producing a low-molecular-weight polybutylene terephthalate resin by melt polymerization, the degree of polymerization (or molecular weight) can be increased to a desired value by solid-phase polymerization under a nitrogen stream or under reduced pressure.

The polybutylene terephthalate resin is preferably produced by continuous melt polycondensation of a dicarboxylic acid component mainly composed of terephthalic acid and a diol component mainly composed of 1,4-butanediol.

Catalysts used in carrying out the esterification reaction may be those conventionally known, such as titanium compounds, tin compounds, magnesium compounds, calcium compounds, and the like. Particularly suitable among these are titanium compounds. 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.

The polybutylene terephthalate resin may be a polybutylene terephthalate resin modified by copolymerization (hereinafter sometimes referred to as "modified polybutylene terephthalate resin"). Polyester ether resins obtained by copolymerizing alkylene glycols (especially polytetramethylene glycol), dimer acid-copolymerized polybutylene terephthalate resins, and isophthalic acid-copolymerized polybutylene terephthalate resins can be used.

When a polyester ether resin obtained by copolymerizing polytetramethylene glycol is used as the modified polybutylene terephthalate resin, the proportion of the tetramethylene glycol component in the copolymer is preferably 3 to 40% by mass, more preferably 5 to 30% by mass. % is more preferred, and 10 to 25% by mass is even more preferred.
When a dimer acid-copolymerized polybutylene terephthalate resin is used as the modified polybutylene terephthalate resin, the ratio of the dimer acid component to the total carboxylic acid component is preferably 0.5 to 30 mol% as carboxylic acid groups. 1 to 20 mol % is more preferable, and 3 to 15 mol % is even more preferable.
When an isophthalic acid-copolymerized polybutylene terephthalate resin is used as the modified polybutylene terephthalate resin, the ratio of the isophthalic acid component to the total carboxylic acid component is preferably 1 to 30 mol % in terms of carboxylic acid groups. 20 mol % is more preferred, and 3 to 15 mol % is even more preferred.
Among the modified polybutylene terephthalate resins, a polyester ether resin obtained by copolymerizing polytetramethylene glycol and an isophthalic acid copolymerized polybutylene terephthalate resin are preferable.

The intrinsic viscosity of the polybutylene terephthalate resin is more preferably in the range of 0.5 to 1.0 dl/g from the viewpoint of moldability and mechanical properties. If one with an intrinsic viscosity lower than 0.5 dl/g is used, the resulting resin composition tends to have low mechanical strength. On the other hand, if it is higher than 1.0 dl/g, the flowability of the resin composition may deteriorate and the moldability may deteriorate.

The amount of terminal carboxyl groups of the polybutylene terephthalate resin may be appropriately selected and determined, but is usually 60 eq/ton or less, preferably 50 eq/ton or less, more preferably 40 eq/ton or less. , 30 eq/ton or less. If it exceeds 60 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 productivity in the production of polybutylene terephthalate resin.

The terminal carboxyl group content of the polybutylene terephthalate resin is a value measured by dissolving 0.5 g of the polyalkylene terephthalate resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol/l benzyl alcohol solution of sodium hydroxide. be. As a method for adjusting the amount of terminal carboxyl groups, any conventionally known method may be used, such as a method of adjusting polymerization conditions such as the raw material charge ratio during polymerization, the polymerization temperature, and a decompression method, or a method of reacting a terminal blocking agent. You can do it.

(A) As the polyalkylene terephthalate resin, one containing a polybutylene terephthalate homopolymer and the modified polybutylene terephthalate resin is also preferable. By containing a specific amount of modified polybutylene terephthalate resin, weld strength and alkali resistance are likely to be improved, which is preferable.
When the polybutylene terephthalate homopolymer and the modified polybutylene terephthalate resin are contained, the content of the modified polybutylene terephthalate resin is preferably 100% by mass in total of the polybutylene terephthalate homopolymer and the modified polybutylene terephthalate resin. It is 5 to 50% by mass, more preferably 10 to 40% by mass, still more preferably 15 to 30% by mass.

Furthermore, (A) polyalkylene terephthalate resin preferably contains polybutylene terephthalate resin and polyethylene terephthalate resin.
When polybutylene terephthalate resin and polyethylene terephthalate resin are contained, the content of polyethylene terephthalate resin is preferably 5% by mass or more and less than 50% by mass with respect to the total 100% by mass of polybutylene terephthalate resin and polyethylene terephthalate resin. , more preferably 10 to 45% by mass, more preferably 15 to 40% by mass.

Polyethylene terephthalate resin is a resin having oxyethyleneoxyterephthaloyl units composed of terephthalic acid and ethylene glycol as main structural units for all structural repeating units, and contains structural repeating units other than oxyethyleneoxyterephthaloyl units. good too. Polyethylene terephthalate resin is produced using terephthalic acid or its lower alkyl ester and ethylene glycol as main raw materials, but other acid components and/or other glycol components may be used together as raw materials.

Acid components other than terephthalic acid include phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3- Examples include phenylenedioxydiacetic acid and structural isomers thereof, dicarboxylic acids such as malonic acid, succinic acid and adipic acid and derivatives thereof, and oxy acids such as p-hydroxybenzoic acid and glycolic acid or derivatives thereof.

Diol components other than ethylene glycol include aliphatic glycols such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, pentamethylene glycol, hexamethylene glycol and neopentyl glycol, and cyclohexane. Alicyclic glycols such as dimethanol, aromatic dihydroxy compound derivatives such as bisphenol A and bisphenol S, and the like are included.

Furthermore, the polyethylene terephthalate resin has a branching component such as a trifunctional acid such as tricarballylic acid, trimellitic acid, trimellitic acid, etc., or a tetrafunctional acid such as pyromellitic acid, or an acid having ester type performance, or glycerin, trimethylolpropane, A copolymer obtained by copolymerizing 1.0 mol % or less, preferably 0.5 mol % or less, more preferably 0.3 mol % or less of an alcohol having a trifunctional or tetrafunctional ester-forming ability such as pentaerythritol. may be

The intrinsic viscosity of the polyethylene terephthalate resin is preferably 0.5-1.0 dl/g, more preferably 0.5-0.9 dl/g, particularly preferably 0.55-0.85 dl/g.

The terminal carboxyl group concentration of the polyethylene terephthalate resin is preferably 3 to 50 eq/ton, more preferably 5 to 40 eq/ton, more preferably 10 to 30 eq/ton.
The terminal carboxyl group concentration of polyethylene terephthalate resin is a value obtained by dissolving 0.5 g of polyethylene terephthalate resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol/l benzyl alcohol solution of sodium hydroxide. be.
As a method for adjusting the amount of terminal carboxyl groups, any conventionally known method may be used, such as a method of adjusting polymerization conditions such as the raw material charge ratio during polymerization, the polymerization temperature, and a decompression method, or a method of reacting a terminal blocking agent. You can do it.

[(B) glass fiber]
The polyester resin composition of the present invention contains (B) glass fibers.
As the glass fiber, if it is usually used for thermoplastic polyester resin, A glass, E glass, alkali resistant glass composition containing zirconia component, chopped strand, roving glass, thermoplastic resin and glass fiber Any known glass fiber can be used regardless of the form of the glass fiber at the time of blending the masterbatch or the like. Among them, the (B) glass fiber used in the present invention is preferably non-alkali glass (E glass) for the purpose of improving the thermal stability of the polyester resin composition of the present invention.

(B) The glass fibers may be treated with a sizing agent or a surface treatment agent. In addition to the untreated glass fibers, a sizing agent or a surface treatment agent may be added for surface treatment during the production of the resin composition of the present invention.

Examples of the sizing agent include resin emulsions such as vinyl acetate resins, ethylene/vinyl acetate copolymers, acrylic resins, epoxy resins, polyurethane resins and polyester resins.
Examples of surface treatment agents include aminosilane compounds such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-(2-aminoethyl)aminopropyltrimethoxysilane; vinyltrichlorosilane; Chlorosilane compounds such as chlorosilane, alkoxysilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxy Epoxysilane-based compounds such as silane, γ-glycidoxypropyltrimethoxysilane, acrylic compounds, isocyanate-based compounds, titanate-based compounds, and epoxy-based compounds are included.
Two or more of these sizing agents and surface treatment agents may be used in combination, and the amount (adhesion amount) thereof used is usually 10% by mass or less, preferably 0.05 to 0.05%, based on the mass of the (B) glass fiber. 5% by mass. By setting the adhesion amount to 10% by mass or less, necessary and sufficient effects can be obtained, which is economical.

(B) Glass fibers may be used in combination of two or more depending on the properties required, and the content thereof is preferably 5 to 150 parts by mass with respect to 100 parts by mass of (A) polyalkylene terephthalate resin. is 10 to 120 parts by mass, more preferably 15 to 100 parts by mass, further preferably 20 to 90 parts by mass, particularly preferably 30 to 80 parts by mass. By containing in such a range, the strength and heat resistance of the obtained molded article can be improved, and the shrinkage reduction effect can be enhanced. When the content exceeds 150 parts by mass, the surface appearance of the molded article deteriorates. If the content is less than 5 parts by mass, the effect of improving the strength is reduced.

It is also preferable that the polyester resin composition of the present invention contain other inorganic fillers in the form of plates, granules, or amorphous, in addition to the (B) glass fibers described above. The plate-like inorganic filler exhibits the function of reducing anisotropy and warpage, and examples thereof include talc, glass flakes, mica, mica, kaolin, and metal foil. Glass flakes are preferred among the plate-like inorganic fillers.
Other particulate or amorphous inorganic fillers include ceramic beads, clays, zeolites, barium sulfate, titanium oxide, silicon oxide, aluminum oxide, magnesium hydroxide, zinc sulfide, and the like.
Talc, titanium oxide, and zinc sulfide are particularly preferred as other inorganic fillers.

The content of the other inorganic filler is preferably 0.1 to 30 parts by mass, more preferably 0.5 parts by mass or more, and still more preferably 100 parts by mass of the (A) polyalkylene terephthalate resin. is 1 part by mass or more, and more preferably 20 parts by mass or less.

[(C) Elastomer]
The polyester resin composition of the present invention contains (C) an elastomer.
The (C) elastomer used in the present invention is not particularly limited, but is preferably a block copolymer containing a component derived from a vinyl aromatic compound, and styrene is preferable as the vinyl aromatic compound.
(C) Elastomer is preferably a styrene block copolymer, particularly preferably a styrene-olefin block copolymer.

The styrene-olefin block copolymer has a region (styrene block) mainly composed of structural units derived from styrene in the molecule, preferably at least one end of the molecule, more preferably at both ends of the molecule. Further, it is preferable to have a region (olefin block) mainly composed of olefin-derived structural units. Here, the phrase “composed mainly of styrene-derived structural units” means that preferably 90% by mass or more of the styrene block is composed of styrene-derived structural units. The same is true for olefin blocks.

Preferred examples of the olefin include ethylene, propylene, and butylene. Moreover, it is also preferable that the olefin block is obtained by hydrogenating a conjugated diene compound.
Conjugated diene compounds include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and phenylbutadiene. , 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, etc. Among these, isoprene is particularly preferred.

When the olefin block is a hydrogenated conjugated diene compound, preferably 50% or more of the carbon-carbon double bonds derived from the conjugated diene compound of the olefin block are hydrogenated, and 75% or more is hydrogenated. More preferably, 95% or more of it is hydrogenated.

The styrene-olefin block copolymer may contain regions other than the styrene block and the olefin block, but said other region is usually 5% by weight or less of the styrene-olefin block copolymer.

Specific examples of styrene-olefin block copolymers include styrene-butadiene-styrene block copolymer (SBS) and hydrogenated products thereof, styrene-isoprene-styrene block copolymer (SIS) and hydrogenated products thereof, and styrene. -Isoprene-butadiene-styrene block copolymer (SIBS) and hydrogenated products thereof are preferred.

The content of the elastomer (C) is 5 to 50 parts by mass, preferably 7 to 40 parts by mass, more preferably 8 parts by mass or more, and still more preferably 10 parts by mass, based on 100 parts by mass of the (A) polyalkylene terephthalate resin. Above, it is particularly preferably 15 mass or more, more preferably 35 mass or less, still more preferably 30 mass or less, and particularly preferably 25 mass or less. (C) When the content of the elastomer is within the above range, the heat shock resistance is improved. If the content is below the above range, the heat shock resistance will be insufficient, and if it exceeds the above range, fluidity and weld strength will be reduced.

[(D) brominated flame retardant]
The polyester resin composition of the present invention contains (D) a brominated flame retardant.
(D) Various brominated flame retardants can be used. Examples of such brominated flame retardants include aromatic compounds, and specific examples include polybrominated benzyl (meth)acrylates such as polypentabromobenzyl acrylate, brominated epoxy compounds, brominated polycarbonates, bromine brominated polystyrene, N,N'-ethylenebis(tetrabromophthalimide) and other brominated imide compounds, brominated polyphenylene ethers such as polybromophenylene ether, brominated phenoxy resins, brominated bisphenol A and the like, particularly polybrominated benzyl (meth)acrylate, is preferred.

Among them, from the viewpoint of good thermal stability, polybrominated benzyl (meth)acrylate such as polypentabromobenzyl acrylate, brominated epoxy compounds such as epoxy oligomer of tetrabromobisphenol A, brominated polystyrene, brominated polycarbonate, brominated Imido compounds are preferred.

Polybrominated benzyl (meth)acrylates are polymers obtained by polymerizing benzyl (meth)acrylates containing bromine atoms alone, or by copolymerizing two or more of them, or by copolymerizing them with other vinyl monomers. The bromine atom is attached to a benzene ring, and the number of additions is preferably 1 to 5, more preferably 4 to 5 per benzene ring.

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

Other vinyl monomers used for copolymerization with benzyl (meth)acrylate containing a bromine atom include, for example, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and benzyl acrylate. Acrylic acid esters; Methacrylic acid esters such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate and benzyl methacrylate; Unsaturated carboxylic acids such as styrene, acrylonitrile, fumaric acid and maleic acid or their anhydrides; Vinyl acetate , vinyl chloride, and the like.

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

As the vinyl-based monomer, xylene diacrylate, xylene dimethacrylate, tetrabrom xylene diacrylate, tetrabrom xylene dimethacrylate, butadiene, isoprene, divinylbenzene, etc. can also be used, and these usually contain a bromine atom. 0.5-fold molar amount or less can be used with respect to the benzyl acrylate or benzyl methacrylate used.

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

Specifically, the brominated epoxy compounds preferably include tetrabromobisphenol A epoxy compounds and bisphenol A-type brominated epoxy compounds represented by glycidyl brominated bisphenol A epoxy compounds.

The molecular weight of the brominated epoxy compound is arbitrary, and may be determined by appropriately selecting it. Preferably, the mass average molecular weight (Mw) is from 3,000 to 100,000. Specifically, the Mw is preferably 10,000 to 80,000, especially 13,000 to 78,000, further 15,000 to 75,000, particularly preferably 18,000 to 70,000, and within this range Among them, those having a high molecular weight are preferred.
The brominated epoxy compound preferably has an epoxy equivalent weight of 3,000 to 40,000 g/eq, preferably 4,000 to 35,000 g/eq, and particularly 10,000 to 30,000 g/eq. is preferred.

A brominated epoxy oligomer can also be used in combination as a brominated epoxy compound flame retardant. At this time, for example, by using about 0 to 50% by mass of an oligomer having an Mw of 5,000 or less, flame retardancy, releasability and fluidity can be appropriately adjusted. The bromine atom content in the brominated epoxy compound is arbitrary, but 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.

As the brominated polycarbonate-based flame retardant, for example, a brominated polycarbonate obtained from brominated bisphenol A, particularly tetrabromobisphenol A is preferable. Its terminal structure includes a phenyl group, a 4-t-butylphenyl group, a 2,4,6-tribromophenyl group, and the like, 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 2-30. If the average number of repeating carbonate units is small, the molecular weight of (A) the polybutylene terephthalate resin may decrease during melting. Conversely, if it is too large, the melt viscosity will increase, causing poor dispersion in the molded product, and the external appearance of the molded product, especially the glossiness, may deteriorate. Therefore, the average number of repeating units is preferably 3 to 15, particularly preferably 3 to 10.

The molecular weight of the brominated polycarbonate-based flame retardant is arbitrary, and may be appropriately selected and determined. preferable.

The brominated polycarbonate flame retardant obtained from the brominated bisphenol A can be obtained, for example, by a conventional method of reacting the brominated bisphenol with phosgene. End capping agents include aromatic monohydroxy compounds, which may be substituted with halogens or organic groups.

（式（１）中、ｔは１～５の整数であり、ｎは繰り返し単位の数である。） Brominated polystyrene preferably includes a 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 produced by brominated polystyrene or by polymerizing brominated styrene monomers, but polymerized brominated styrene contains free bromine (atoms) is preferred because the amount of
In addition, in the general formula (1), the CH group to which the brominated benzene is bonded may be substituted with a methyl group. Brominated polystyrene may also be a copolymer obtained by copolymerizing other vinyl monomers. Vinyl monomers in this case include styrene, α-methylstyrene, acrylonitrile, methyl acrylate, butadiene and vinyl acetate. The brominated polystyrene may be used singly or as a mixture of two or more different structures, and may contain units derived from styrene monomers with different numbers of bromines in a single molecular chain.

Specific examples of brominated polystyrene include 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- methylstyrene), poly(2,4,6-tribromo-α-methylstyrene) and poly(2,4,5-tribromo-α-methylstyrene), and poly(2,4,6-tribromo styrene), 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.

The brominated polystyrene preferably has a repeating unit number n (average degree of polymerization) of 30 to 1,500, more preferably 150 to 1,000, particularly 300 to 800 in the general formula (1). preferred. If the average degree of polymerization is less than 30, blooming tends to occur. Further, the mass average molecular weight (Mw) of the brominated polystyrene is preferably 5,000 to 500,000, more preferably 10,000 to 500,000, 10,000 to 300,000, Among them, 10,000 to 100,000 is more preferable, and 10,000 to 70,000 is particularly preferable.
In particular, in the case of the above brominated polystyrene, the weight average molecular weight (Mw) is preferably 50,000 to 70,000, and in the case of brominated polystyrene obtained by polymerization, the weight average molecular weight (Mw) is 10. ,000 to 30,000. The mass average molecular weight (Mw) can be obtained as a value converted to standard polystyrene by GPC measurement.

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

（一般式（２）中、Ｄはアルキレン基、アルキルエーテル基、ジフェニルスルフォン基、ジフェニルケトン基あるいはジフェニルエーテル基を示す。ｉは１～４の整数である。） As the brominated imide compound, one represented by the following general formula (2) is preferable.

(In general formula (2), D represents an alkylene group, an alkyl ether group, a diphenylsulfone group, a diphenylketone 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 Tetrabromophthalimido)butane, N,N'-(bistetrabromophthalimido)diethyl ether, N,N'-(bistetrabromophthalimido)dipropyl ether, N,N'-(bistetrabromophthalimido)dibutyl ether, N ,N'-(bistetrabromophthalimide)diphenylsulfone, N,N'-(bistetrabromophthalimide)diphenylketone, N,N'-(bistetrabromophthalimide)diphenylether and the like.

（一般式（３）中、ｉは１～４の整数である。）
中でも、上記式（３）におけるｉが４である、Ｎ，Ｎ’－エチレンビス（テトラブロモフタルイミド）が好ましい。 As the brominated imide compound, one in which D is an alkylene group in the above general formula (2) is preferred, and a brominated phthalimide compound represented by the following general formula (3) is particularly preferred.

(In general formula (3), i is an integer of 1 to 4.)
Among them, N,N'-ethylenebis(tetrabromophthalimide) in which i is 4 in the above formula (3) is preferable.

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

(D) The content of the brominated flame retardant is 5 to 50 parts by mass, preferably 10 to 45 parts by mass, more preferably 15 parts by mass or more, relative to 100 parts by mass of the (A) polyalkylene terephthalate resin. It is preferably 20 parts by mass or more, more preferably 40 parts by mass or less, still more preferably 35 parts by mass or less, and most preferably 33 parts by mass or less. When the content of the brominated flame retardant (D) is within the above range, a resin composition having excellent heat shock resistance and sufficient flame retardancy can be obtained. (D) If the content of the brominated flame retardant is too small, the flame retardancy of the resin composition tends to be insufficient. is likely to occur.

[(E) antimony compound]
The polyester resin composition of the present invention contains (E) an antimony compound. As the (E) antimony compound, antimony trioxide (Sb ₂ O ₃ ), antimony pentoxide (Sb ₂ O ₅ ), sodium antimonate, and the like are preferable, and among these, antimony trioxide is particularly preferable.

In antimony trioxide, the total weight ratio of (D) bromine atoms derived from brominated flame retardants and (E) antimony atoms derived from antimony compounds in the resin composition is 3 to 25% by mass. It is preferably 4 to 22% by mass, and even more preferably 10 to 20% by mass. If it is less than 3% by mass, the flame retardancy tends to be lowered, and if it exceeds 25% by mass, the mechanical strength tends to be lowered. The mass ratio (Br/Sb) of bromine atoms to antimony atoms is preferably 0.3-5, more preferably 0.3-4. By setting it as such a range, flame retardancy tends to be easily exhibited, and it is preferable.

(E) The antimony compound is preferably blended as a masterbatch with a thermoplastic resin, preferably (A) a polyalkylene terephthalate resin. As a result, the (E) antimony compound is more likely to exist in the (A) polyalkylene terephthalate resin phase, the thermal stability during melt-kneading and molding is improved, the drop in impact resistance is suppressed, and the Variation in flammability and impact resistance tends to decrease.
The content of (E) the antimony compound in the masterbatch is preferably 20 to 90% by mass. If (E) the antimony compound is less than 20% by mass, the proportion of the antimony compound in the flame retardant masterbatch is small, and the effect of improving the flame retardancy of the (A) polyalkylene terephthalate resin to which it is blended tends to be small. On the other hand, when (E) the antimony compound exceeds 90% by mass, the dispersibility of the antimony compound tends to decrease, and when this is blended with the (A) polyalkylene terephthalate resin, the flame retardancy of the resin composition becomes unstable. In addition, the workability during the production of the masterbatch tends to deteriorate, and for example, when using an extruder, the strand is not stable and tends to break easily, which is not preferable.
The content of (E) the antimony compound in the masterbatch is more preferably 30% by mass or more, further 40% by mass or more, still more 50% by mass or more, particularly 60% by mass or more, and most preferably 70% by mass or more. The upper limit is more preferably 85% by mass or less, still more preferably 80% by mass or less.

(E) The content of the antimony compound is 1 to 20 parts by mass, preferably 3 to 15 parts by mass, more preferably 5 parts by mass or more, with respect to 100 parts by mass of the polyalkylene terephthalate resin (A). It is 7 parts by mass or more, more preferably 13 parts by mass or less, still more preferably 12 parts by mass or less, especially 11 parts by mass or less. If it is less than the above lower limit, the flame retardancy tends to be lowered, and if it exceeds the above upper limit, the crystallization temperature is lowered, the releasability is deteriorated, and mechanical properties such as impact resistance are lowered.

[(F) epoxy group-containing plasticizer]
The polyester resin composition of the present invention contains (F) a plasticizer containing an epoxy group and having a glass transition temperature of −50° C. or lower.
(F) The plasticizer is a plasticizer containing an epoxy group, and an epoxy group-containing acrylic copolymer obtained by polymerizing a monomer component containing a (meth)acrylic acid ester monomer and copolymerizing a glycidyl group-containing monomer. Polymers are preferred.

Examples of (meth)acrylic acid ester monomers include aliphatic (meth)acrylic acid ester monomers such as (meth)acrylic acid alkyl esters, and aromatic (meth)acrylic acid esters such as (meth)acrylic acid phenyl esters. acid ester-based monomers.

Aliphatic (meth)acrylic acid ester monomers include, for example, (meth)acrylic acid alkyl esters in which the number of carbon atoms in the alkyl group is usually 1 to 12, particularly preferably 1 to 10, and more preferably 1 to 8. and (meth)acrylic acid esters having an alicyclic structure.
(Meth)acrylic acid alkyl esters include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, n- Propyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl ( meth)acrylate and the like.
Examples of (meth)acrylic acid esters having an alicyclic structure include cyclohexyl (meth)acrylate and isobornyl (meth)acrylate.

Examples of aromatic (meth)acrylic acid ester monomers include phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyldiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (Meth)acrylates, phenoxypolyethylene glycol (meth)acrylates, and the like.

As the (meth)acrylic acid ester-based monomer, aliphatic (meth)acrylic acid ester-based monomers are preferable, particularly (meth)acrylic acid alkyl esters, and further (meth)acrylic acid having an alkyl group having 1 to 12 carbon atoms. Alkyl esters are preferred, methyl (meth)acrylate and n-butyl (meth)acrylate are preferred, and methyl (meth)acrylate is more preferred.

Examples of glycidyl group-containing monomers include glycidyl (meth)acrylate and allyl glycidyl ether, with glycidyl (meth)acrylate and glycidyl methacrylate being particularly preferred.

Furthermore, it is also preferable that copolymerizable monomers other than (meth)acrylic monomers and glycidyl group-containing monomers are copolymerized. Examples of other copolymerizable monomers include acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, and vinyl stearate.

In such an epoxy group-containing acrylic copolymer, the content of each monomer is preferably 50 to 99% by mass for (meth)acrylic acid ester monomers, and preferably 1 to 30% by mass for glycidyl group-containing monomers. , and other copolymerizable monomers are preferably 0 to 50% by mass.

The weight average molecular weight of the epoxy group-containing acrylic copolymer in terms of GPC polystyrene is preferably in the range of about 1,000 to 5,000.

(F) The epoxy group-containing plasticizer plasticizes the amorphous part of the polyalkylene terephthalate without bleeding because the epoxy group has reactivity with the carboxyl group or hydroxyl group of the (A) polyalkylene terephthalate resin. It is presumed that the toughness at low temperatures is improved, and the heat resistance of the resin composition can be significantly improved.

In the present invention, the (F) epoxy group-containing plasticizer contains one having a glass transition temperature (Tg) of -50°C or lower. Some epoxy group-containing plasticizers have a glass transition temperature of about -100°C to +180°C, and among these, by including those with a Tg of -50°C or lower, the low-temperature toughness of the polyalkylene terephthalate resin is improved. be able to.
Examples of such epoxy group-containing plasticizers include "ARUFON UG-4000" (mass average molecular weight: 3000, glass transition temperature: -61°C) and "ARUFON UG-4010" (weight average molecular weight : 2900, glass transition temperature: -57°C).

(F) The epoxy value of the epoxy group-containing plasticizer is preferably 1.0 meq/g or more, and its upper limit is preferably 2.5 meq/g or less. When the epoxy value is less than 1.0, it is difficult to sufficiently improve the heat shock resistance, while when it exceeds 2.5, the fluidity tends to be significantly reduced.
The epoxy value is preferably 1.0 or more, more preferably 1.2 or more, preferably 2.5 or less, further preferably 2.2 or less, and particularly preferably 2.0 or less.
The epoxy value was measured by dissolving the sample in benzyl alcohol and 1-propanol, adding an aqueous solution of potassium iodide and a bromophenol blue indicator to the solution, and titrating with 1N hydrochloric acid. The inside of the reaction system turned from blue to yellow. is generally calculated as the equivalent point.

The content of (F) the epoxy group-containing plasticizer is 1 to 10 parts by mass, preferably 1.5 to 8 parts by mass, more preferably 2 parts by mass, relative to 100 parts by mass of the polyalkylene terephthalate resin (A). ~7 parts by mass. If the amount is less than 1 part by mass, the heat shock resistance is not sufficient, and if the amount exceeds 10 parts by mass, the plasticizer bleeds out, and the appearance of the molded product tends to deteriorate, and the fluidity also significantly decreases.

[Anti-dripping agent]
The polyester resin composition of the present invention preferably contains an anti-dripping agent. As the anti-dripping agent, a fluoropolymer is preferred, and a fluoroolefin resin is particularly preferred.

Fluoroolefin resins include, for example, polymers and copolymers containing a fluoroethylene structure. Specific examples thereof include difluoroethylene resin, tetrafluoroethylene resin, tetrafluoroethylene/hexafluoropropylene copolymer resin, and the like. Among them, tetrafluoroethylene resin and the like are preferable. As this fluoroethylene resin, a fluoroethylene resin having fibril-forming ability is preferable.
Examples of fluoroethylene resins having fibril-forming ability include Teflon (registered trademark) 6J manufactured by Mitsui-DuPont Fluorochemicals, Polyflon (registered trademark) F201L and Polyflon F103 manufactured by Daikin Industries, Ltd.

Examples of aqueous dispersions of fluoroethylene resins include Teflon (registered trademark) 30J manufactured by Mitsui Chemours Fluoro Products, Fluon D-1 manufactured by Daikin Industries, Ltd., and TF1750 manufactured by Sumitomo 3M. Furthermore, a fluoroethylene polymer having a multi-layered structure obtained by polymerizing vinyl monomers can also be used as the fluoropolymer. Specific examples thereof include Metabrene (registered trademark) A-3800 manufactured by Mitsubishi Chemical Corporation.

The content of the anti-dripping agent is preferably 0.05 to 1 part by mass, more preferably 0.1 part by mass or more, and still more preferably 0.15 parts by mass with respect to 100 parts by mass of the (A) polyalkylene terephthalate resin. It is not less than 0.2 parts by mass, particularly preferably not less than 0.2 parts by mass, more preferably not more than 0.9 parts by mass, still more preferably not more than 0.85 parts by mass, and particularly preferably not more than 0.8 parts by mass. If the content of the anti-dripping agent is too low, the flame retardancy of the resin composition may be insufficient. may occur.

[Release agent]
The polyester resin composition of the present invention preferably contains a release agent, and the content thereof is preferably in the range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the (A) polyalkylene terephthalate resin. . As the release agent, known release agents that are commonly used for polyester resins can be used. Among them, the release agent is selected from polyolefin-based compounds, fatty acid ester-based compounds, and silicone-based compounds in terms of good alkali resistance. One or more mold release agents are preferred, especially polyolefinic compounds.

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

Examples of fatty acid ester compounds include saturated or unsaturated aliphatic monovalent or divalent carboxylic acid esters, fatty acid esters such as glycerin fatty acid esters, sorbitan fatty acid esters, and partially saponified products thereof. Among them, mono- or di-fatty acid esters composed of fatty acids having 11 to 28 carbon atoms, preferably 17 to 21 carbon atoms, and alcohols are preferred.

Aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetralyacontanoic acid, montanic acid, adipic acid, and azelaic acid. etc. Also, the aliphatic carboxylic acid may be an alicyclic carboxylic acid.
Alcohols may include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have substituents such as fluorine atoms and aryl groups. Among these, monohydric or polyhydric saturated alcohols having 30 or less carbon atoms are preferred, and saturated monohydric or polyhydric alcohols having 30 or less carbon atoms are more preferred. Here, the term "aliphatic" also includes alicyclic compounds.
Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol, and the like. is mentioned.
The above ester compound may contain aliphatic carboxylic acid and/or alcohol as impurities, or may be a mixture of a plurality of compounds.

Specific examples of fatty acid ester compounds include glycerin monostearate, glycerin monobehenate, glycerin dibehenate, glycerin-12-hydroxy monostearate, sorbitan monobehenate, pentaerythritol monostearate, and pentaerythritol distearate. rate, stearyl stearate, ethylene glycol montanic acid ester, and the like.

As the silicone-based compound, a modified compound is preferable from the viewpoint of compatibility with the polyalkylene terephthalate resin. Modified silicone oils include silicone oils in which organic groups are introduced into side chains of polysiloxane, silicone oils in which organic groups are introduced into both ends and/or one end of polysiloxane, and the like. 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, a phenol group, and the like, preferably an epoxy group. As the modified silicone oil, a silicone oil obtained by introducing an epoxy group into the side chain of polysiloxane is particularly preferable.

The content of the release agent is preferably 0.1 to 3 parts by mass, more preferably 0.2 to 2.5 parts by mass, relative to 100 parts by mass of the (A) polyalkylene terephthalate resin. . If the amount is less than 0.1 parts by mass, the surface properties tend to deteriorate due to poor mold release during melt molding. A haze may be seen on the body surface. The content of the release agent is more preferably 0.5 to 2 parts by mass.

[Stabilizer]
It is preferable that the polyester resin composition of the present invention contains a stabilizer such as an antioxidant because it has effects of improving thermal stability and preventing deterioration of mechanical strength, transparency and hue. As antioxidants, sulfur-based stabilizers and phenol-based stabilizers are preferred.

As the sulfur-based stabilizer, any conventionally known sulfur atom-containing compound can be used, and thioethers are particularly preferable. Specific examples include didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis(3-dodecylthiopropionate), thiobis(N-phenyl-β-naphthylamine ), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropylxanthate, trilauryltrithiophosphite. Among these, pentaerythritol tetrakis(3-dodecylthiopropionate) is preferred.

Phenolic stabilizers include, for example, pentaerythritol tetrakis (3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-tert-butyl-4 -hydroxyphenyl)propionate, thiodiethylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), pentaerythritol tetrakis(3-(3,5-di-neopentyl-4-hydroxyphenyl) ) propionate) and the like. Among these, pentaerythritol-letetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl ) propionate is preferred.

One stabilizer may be contained, or two or more stabilizers may be contained in any combination and ratio.

The content of the stabilizer is preferably 0.001 to 2 parts by mass with respect to 100 parts by mass of the polyalkylene terephthalate resin (A). If the content of the stabilizer is less than 0.001 part by mass, it is difficult to expect an improvement in the thermal stability and compatibility of the resin composition, and a decrease in molecular weight and deterioration in color during molding are likely to occur. If it exceeds, the amount becomes excessive, and the generation of silver and the deterioration of the hue tend to occur more easily. The stabilizer content is more preferably 0.01 to 1.5 parts by mass, and still more preferably 0.1 to 1 part by mass.

[Other ingredients]
The polyester resin composition of the present invention may optionally contain conventionally known various resin additives as long as they do not impair the effects of the present invention. Examples of various resin additives include ultraviolet absorbers, weather stabilizers, lubricants, colorants such as dyes and pigments, catalyst deactivators, antistatic agents, foaming agents, crystal nucleating agents, and crystallization accelerators.

The polyester resin composition of the present invention may contain other thermoplastic resins, thermosetting resins, and the like, if necessary, as long as the effects of the present invention are not impaired. Other thermoplastic resins include polyamide resins, polyethylene resins, polypropylene resins, acrylic resins, polycarbonate resins, polyacetal resins, polyphenylene oxide resins, polyphenylene sulfide resins, and liquid crystal polyester resins. Phenolic resins, melamine resins, silicone resins, epoxy resins and the like are included. These may be one type or two or more types.

The method for producing the polyester resin composition of the present invention is not limited to a specific method, but a melting and kneading method is preferred. The melting/kneading method can be a method commonly used for thermoplastic resins.

Melting and kneading methods include, for example, (A) a polyalkylene terephthalate resin, (C) an elastomer, (D) a brominated flame retardant, (E) an antimony compound, and (F) a plasticizer. A method of uniformly mixing other ingredients with a Henschel mixer, ribbon blender, V-type blender, tumbler, etc., and then melting and kneading with a single-screw or multi-screw kneading extruder, roll, Banbury mixer, Labo Plastomill (Brabender), etc. mentioned. Incidentally, (B) the glass fiber is preferably supplied from the side feeder of the kneading extruder because it is possible to suppress breakage of the glass fiber and to disperse the glass fiber.
The temperature and kneading time for melting and kneading can be selected according to the type of components constituting the resin component, the ratio of the components, the type of melting and kneading machine, etc. The temperature for melting and kneading is 200 to 300. °C range is preferred. If the temperature exceeds 300°C, thermal deterioration of the resin component becomes a problem, and the physical properties of the molded product may deteriorate and the appearance may deteriorate.

The method for producing the desired molded article from the polyester resin composition of the present invention is not particularly limited, and molding methods conventionally employed for thermoplastic resins, namely injection molding, insert molding, blow molding, Extrusion molding, compression molding and the like can be used. Among these, injection molding and insert molding are particularly preferable, and insert molding for inserting a metal member is particularly suitable.
In the case of a molded product with a metal member inserted, such as a motor stator core sealed product, due to the difference in thermal expansion/contraction rate due to temperature changes between the polyalkylene terephthalate resin and the internal metal member,

Molded products include, for example, various storage containers, electric and electronic parts, office automation (OA) equipment parts, home appliance parts, machine mechanism parts, building material parts, other precision equipment parts, automobile mechanism parts, sanitary parts, etc. Applicable.
In particular, since the polyester resin composition of the present invention is particularly excellent in heat shock resistance, it is suitable as a molded product in which a metal member is inserted, for example, an insert molded product such as electrical appliance parts and automotive electrical parts.

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples, but the present invention should not be construed as being limited to the examples described below.
Raw material components used in Examples and Comparative Examples are shown in Table 1 below.

[Examples 1-2, Comparative Examples 1-5]
<Production of polyester resin composition>
Each component other than the glass fiber described in Table 1 above is blended at the ratio (all parts by mass) shown in Table 2 below, and this is blended with a 30 mm vent-type twin-screw extruder (manufactured by Japan Steel Works, Ltd., two Using a screw extruder TEX30α), glass fibers are supplied from a side feeder, melted and kneaded under the conditions of a barrel temperature of 270 ° C., a discharge rate of 40 kg, and a screw rotation speed of 200 rpm, extruded into a strand, and then a strand cutter It was pelletized to obtain pellets of a polybutylene terephthalate resin composition.

[Measurement evaluation method]
Various physical properties and performances in Examples and Comparative Examples were measured and evaluated by the following methods.

[MVR]
MVR is the melt flow volume MVR per unit time (unit: cm ³ /10 min) of the pellets obtained above under the conditions of 265 ° C. and a load of 5 kgf using a melt indexer manufactured by Takara Industry Co., Ltd. was measured.
[Determination of formability]
Based on the MVR value obtained above, evaluation of moldability was performed according to the following criteria.
○: MVR is 20 cm ³ /10 min or more △: MVR is less than 20 cm ³ /10 min, 10 cm ³ /10 min or more ×: MVR is less than 10 cm ³ /10 min

[Tensile breaking strength, tensile breaking elongation]
After drying the pellets obtained above at 120 ° C. for 5 hours, using an injection molding machine manufactured by Nippon Steel Corporation (clamping force 85 T), under the conditions of a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C., ISO multi-purpose Specimens (4 mm thick) were injection molded.
Based on ISO527, tensile strength at break (unit: MPa) and tensile elongation at break (unit: %) were measured using the above ISO multi-purpose test piece (4 mm thick).
[Maximum flexural strength, flexural modulus]
Using the ISO multi-purpose test piece (4 mm thick), the maximum flexural strength (unit: MPa) and flexural modulus (unit: MPa) were measured at a temperature of 23° C. in accordance with ISO178.
[Notched Charpy impact strength]
Notched Charpy impact strength (unit: kJ/m ² ) was measured at a temperature of 23° C. for a notched test piece obtained by notching the above ISO multipurpose test piece (4 mm thick) according to ISO179.

[Combustibility (UL-94)]
Combustibility (flame retardancy) was tested using five test pieces (thickness: 0.8 mm) according to the method of Subject 94 (UL-94) of Underwriters Laboratories.
Flammability was classified into V-0, V-1 and V-2 according to the evaluation method described in UL-94.

[Heat shock resistance]
After drying the obtained pellets at 120 ° C. for 6 hours, a rectangular parallelepiped iron ( As shown in FIG. 2, an insert 1 (16 mm long, 33 mm wide, 3 mm thick) of SUS) was charged into a mold cavity 4 with a support pin 2 and inserted (insert iron piece 3). An insert-molded product shown in FIG. 3 (length 18 mm×width 35 mm×thickness 5 mm) was produced by insert molding. The thickness of the resin portion of this insert-molded product is 1 mm. Two weld lines 6 are generated in the traces 5 of the support pins in the insert-molded product. Using this insert-molded product, a heat shock test was performed using a heat shock tester TSA-102ES manufactured by ESPEC.
The conditions of the heat shock test were -40°C for 60 minutes → 150°C for 60 minutes, and subjected to the heat shock test, and the average number of cycles at which cracks occurred in a total of 10 weld lines of 5 molded products. displayed in

[Determination of heat shock resistance]
Based on the number of cycles (average value) obtained above, evaluation of heat shock resistance was performed according to the following criteria.
○: The number of cycles is 350 or more △: The number of cycles is less than 350, 260 or more ×: The number of cycles is less than 260 Table 2 below shows the evaluation results.

INDUSTRIAL APPLICABILITY The polyester resin composition of the present invention can achieve extremely high heat shock resistance and is also excellent in impact resistance. It is a very useful material for manufacturing. Furthermore, it is useful in a wide range of fields such as electrical and electronic parts, building material parts, sanitary parts and machine parts.

1. insert iron piece2. support pin3. 4. Insert iron piece inserted into the mold. cavity5. Traces of support pins6. Weld line

Claims (6)

(A) Per 100 parts by mass of polyalkylene terephthalate resin, (B) 5 to 150 parts by mass of glass fiber, (C) 5 to 50 parts by mass of elastomer, (D) 5 to 50 parts by mass of brominated flame retardant, (E) 1 to 20 parts by mass of an antimony compound, and (F) 1 to 10 parts by mass of a plasticizer containing an epoxy group and having a glass transition temperature of −50° C. or lower ,
(F) the plasticizer containing an epoxy group has a GPC polystyrene equivalent weight average molecular weight of 1000 to 5000,
(D) A polyester resin composition, wherein the brominated flame retardant is polybrominated benzyl (meth)acrylate . 2. The polyester resin composition according to claim 1, wherein (C) the elastomer is a block copolymer containing a component derived from a vinyl aromatic compound. 3. The polyester resin composition according to claim 1 , wherein (F) the plasticizer has an epoxy value of 1.0 meq/g or more. 4. The polyester resin composition according to any one of claims 1 to 3 , wherein (A) the polyalkylene terephthalate resin has an intrinsic viscosity of 0.50 to 1.00 dl/g. A molded article made of the polyester resin composition according to any one of claims 1 to 4 . The molded product according to claim 5 , which is an insert molded product with metal.

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