JPH09124909A - Polyester resin composition excellent in impact resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester resin composition having excellent impact resistance and moldability and improved in heat stability by mixing a thermoplastic aromatic polyester with a specified polyether ester block copolymer. SOLUTION: This resin composition comprises 100 pts.wt. thermoplastic aromatic polyester having an intrinsic viscosity of 0.4-1.2 and a melting point of 200 deg.C or above and 1-100 pts.wt. polyether ester block copolymer prepared by copolymerizing an acid component comprising 60-100mol% terephthalic acid and 40-0mol% isophthalic acid with 40-80wt.%, based on the entire glycol component, poly(alkylene oxide) glycol component represented by the formula [wherein (x) is -H, -CH3 or the like; n>=0, m>=0; and 120>=n+m]>=20) and a glycol component comprising 65-100mol% tetramethylene glycol and 35-0mol% ethylene glycol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition having excellent impact resistance, and more specifically, it is excellent in impact resistance and moldability obtained by blending a specific polyether ester block copolymer. And a polyester resin composition.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PET)
And thermoplastic aromatic polyester resins represented by polybutylene terephthalate (PBT) are excellent in mechanical strength, chemical resistance, electrical insulation, etc.
Widely used for automobile parts and other machine parts.

However, the impact resistance of a molded product made of a polyester resin is not always sufficient, and further improvement has been desired. As a method for improving the impact resistance of polyester, it has been attempted to blend various elastomers (US Pat. No. 4,172,859, JP-B-58-4).
7419, Japanese Patent Publication No. 59-10699, Japanese Patent Fair 1-5
No. 01713), the improvement effect was not sufficient.

Although PET is a resin having excellent thermal properties, its field of use is limited because it has a slower crystallization rate than PBT and has a problem in moldability, and improvement in moldability is desired. It was As an attempt to improve the crystallization rate of PET, for example, US Pat.
No. 3 discloses that a soft segment of polytetramethylene glycol can be introduced into the PET polymer chain for modification. U.S. Pat. No. 4,322,335 discloses PET molding compositions modified to increase the crystallization rate by incorporating soft segments of polyoxyalkylene glycol into the PET polymer chain.

However, it has been difficult to simultaneously improve the impact resistance of the polyester resin molding material and increase the crystallinity by increasing the crystallization speed to a practically necessary level.

Further, when a plasticizer such as polyethylene glycol is added to promote crystallization, decomposition and deterioration occur when the composition is prepared, the molding process is performed, or the molded product is used in a high temperature atmosphere, and the product is deteriorated. There was a problem of discoloration and loss of commercial value.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polyester having excellent impact resistance, excellent moldability, and improved heat stability. It is to provide a resin composition. Furthermore, it aims at providing the polyester resin composition excellent in flame retardancy in addition to these characteristics.

The heat stability, which is one of the problems to be solved by the present invention, will be described in more detail. The main uses of polyester resin are electrical and electronic parts, automobile parts,
In other uses of mechanical parts, the parts are often colored before being used. In this case, a white pigment such as titanium dioxide is mixed in advance with the resin forming the component to prepare the molded product so as to have a white base color, and then the desired color may be applied. It is commonly done. These parts are often placed in a high temperature environment in the subsequent steps or in use as a product, and it has been desired to improve color stability at high temperatures.

An object of the present invention is to improve the thermal stability of such a color, and further to provide a resin composition having both impact resistance and moldability.

[0010]

Means for Solving the Problems The inventors of the present invention have made earnest studies on improvement of moldability and impact resistance of polyester resin, and as a result, thermoplastic aromatic polyester has a specific polyether ester block copolymer The present inventors have found that the resin composition prepared by incorporating the coalescence exhibits not only good moldability and excellent impact resistance, but also excellent heat resistance stability.

That is, in the present invention, the [A] intrinsic viscosity is 0.4.
To 1.2 and 100 parts by weight of the thermoplastic aromatic polyester (A) having a melting point of 200 ° C. or higher, 60 to 1 of terephthalic acid is added to [B] [a] total acid component.
Acid component (a) containing 00 mol% and 40 to 0 mol% of isophthalic acid, [b] poly (alkylene oxide) glycol component (b) represented by the following general formula (I),

[0012]

Embedded image

[Wherein X is --H, --CH ₃ , --CH
₂ Cl, —CH ₂ Br, —CH ₂ I or —CH ₂ OC
H ₃ and n and m are n ≧ 0, m ≧ 0 and 120
≧ (n + m) ≧ 20] [C] Tetramethylene glycol is 65 to 100 mo based on all glycol components (excluding (b) component)
1% and a glycol component (c) containing 35 to 0 mol% of ethylene glycol are copolymerized with a polyether ester block, and the copolymerization amount of the component (b) is 40% of the total glycol component. ˜80% by weight of polyether ester block copolymer (B) 1-1
It is a polyester resin composition excellent in impact resistance, which is prepared by blending 100 parts by weight.

The present invention will be described in detail below.

In the thermoplastic aromatic polyester (A) used in the present invention, the acid component is terephthalic acid and / or isophthalic acid, and the diol component is an aliphatic compound such as ethylene glycol, trimethylene glycol or tetramethylene glycol. The main component is an aromatic polyester composed of at least one kind of diol. Of these, polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate are preferred.
Polyethylene terephthalate is particularly preferable. Further, as the thermoplastic aromatic polyester, a part of the above polyester may be substituted with a copolymerization component, and as the copolymerization component, phthalic acid; alkyl-substituted phthalic acid such as methyl terephthalic acid and methyl isophthalic acid;
Naphthalenedicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid; Diphenyldicarboxylic acid such as 4,4′-diphenyldicarboxylic acid and 3,4′-diphenyldicarboxylic acid Acids; aromatic dicarboxylic acids such as diphenoxyethanedicarboxylic acids such as 4,4'-diphenoxyethanedicarboxylic acid; aliphatic such as succinic acid, adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, etc. Alicyclic dicarboxylic acids; alicyclic diols such as 1,4-cyclohexanedimethanol; dihydroxybenzenes such as hydroquinone and resorcin; 2,2'-bis (4-hydroxyphenyl) propane, 2,2'-bis ( Bi such as 4-hydroxyphenyl) sulfone Phenols; can be exemplified ε- hydroxycaproic acid, hydroxybenzoic acid, and the like oxycarboxylic acids such as hydroxy-ethoxy benzoic acid, aromatic diols such as polyether diols obtained from such glycols bisphenol and ethylene glycol. Furthermore, as a branching component to the above aromatic polyester,
An acid having a polyfunctional ester forming ability such as trimesic acid or trimellitic acid; or an alcohol having a polyfunctional ester forming ability such as glycerin, trimethylolpropane or pentaerythritol is 1.0 mol% or less, preferably 0. 0.5 mol% or less, more preferably 0.3 mol%
You may copolymerize in the following ratios.

The thermoplastic aromatic polyester (A) used in the present invention is required to have an intrinsic viscosity of 0.4 to 1.2. When it is less than 0.4, sufficient properties cannot be obtained, and when it is more than 1.2, the melt viscosity is high and the fluidity is lowered to deteriorate the moldability, which is not preferable. Here, the intrinsic viscosity (IV) in the present specification is a calculated value based on a value measured at 35 ° C. using o-chlorophenol as a solvent.

The thermoplastic aromatic polyester (A) used in the present invention must have a melting point of 200 ° C. or higher. If the melting point is 200 ° C. or less, only molded products having insufficient heat resistance during use can be obtained.

The above-mentioned thermoplastic aromatic polyester (A)
Can be produced by an ordinary production method, for example, a melt polycondensation reaction or a method in which this is combined with a solid phase polymerization reaction. For example, when describing a production example of polyethylene terephthalate, terephthalic acid or its ester-forming derivative (eg, lower alkyl ester such as dimethyl ester, monomethyl ester) and ethylene glycol or its ester-forming derivative are heated in the presence of a catalyst. It can be produced by a method of reacting and then polymerizing the obtained glycol ester of terephthalic acid to a predetermined degree of polymerization in the presence of a catalyst.

The polyether ester block copolymer (B) used in the present invention comprises 60 to 100 mol% of terephthalic acid and 4 parts of isophthalic acid based on the total acid components.
An acid component (a) containing 0 to 0 mol%, a poly (alkylene oxide) glycol component (b) represented by the following general formula (I),

[0020]

Embedded image

[Wherein, X is --H, --CH ₃ , --CH
₂ Cl, —CH ₂ Br, —CH ₂ I or —CH ₂ OC
H ₃ and n and m are n ≧ 0, m ≧ 0 and 120
≧ (n + m) ≧ 20], and tetramethylene glycol is contained in an amount of 65 to 100 mol% and ethylene glycol is included in an amount of 35 to 0 mol% based on all glycol components (excluding the component (b)). A polyether ester block copolymer obtained by copolymerizing a glycol component (c) with a glycol component (c), and the copolymerization amount of the component (b) is 40 to 80% by weight of the total glycol component. It is a combination (B).

The polyether ester block copolymer (B) contains 65 mol of tetramethylene glycol based on all glycol components (excluding the component (b)).
% Or more, and if the content of tetramethylene glycol in the polyether ester block copolymer is less than 65 mol%, moldability becomes poor.

In the polyether ester block copolymer (B), a dicarboxylic acid other than terephthalic acid and isophthalic acid, such as phthalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, and trimellitic acid as the acid component (a). Acid, pyromellitic acid, naphthalenedicarboxylic acid,
Cyclohexanedicarboxylic acid may be copolymerized.

The polyether ester block copolymer (B) contains, as a glycol component (c), diols other than tetramethylene glycol and ethylene glycol, such as trimethylene glycol, 1,5-pentanediol and 1,6-hexane. A diol, diethylene glycol, 1,4-cyclohexane diol and 1,4-cyclohexane dimethanol may be copolymerized.

The polyether ester block copolymer (B) is copolymerized with a poly (alkylene oxide) glycol component (b). The amount of this (b) component is 40 to 80 based on the total glycol component. %, Preferably 40-70% by weight. When it is less than 40% by weight, the effect of improving impact resistance is small, and when it is more than 80% by weight, polymer fusion and sticking occur to cause problems in the process.

In the above formula (I), X is a hydrogen atom (-
H), —CH ₃ , —CH ₂ Cl, —CH ₂ Br, —CH
_It should be either ₂ I or —CH ₂ OCH ₃ . When X is a complicated group other than these, it is difficult to increase the polymerization degree of the copolymer because of steric hindrance. Further, those in which the main chain of the polyethylene glycol unit is directly substituted with halogen or an alkoxy group have strong decomposability and are not preferred. X is preferably a hydrogen atom.

In the above formula (I), n and m are required to satisfy the above definition, but when the value of (n + m) is less than 20, the block property of the block copolymer is lowered and the impact resistance is lowered. However, when the value of (n + m) exceeds 120, the polymerizability is lowered, not only it becomes difficult to obtain a copolymer having a sufficient degree of polymerization, but also the impact resistance is lowered.

The blending amount of the polyether ester block copolymer (B) used in the present invention is 1 to 100 relative to 100 parts by weight of the thermoplastic aromatic polyester (A).
Parts by weight. It is preferably 1 to 75 parts by weight, more preferably 5 to 50 parts by weight. When the amount is less than 1 part by weight, the effect of improving impact resistance is small, and when the amount is more than 100 parts by weight, polymer fusion and sticking occur to cause problems in the process.

The brominated flame retardant (C) preferably used in the present invention is a brominated bisphenol A compound and / or a vinyl polymer flame retardant having a brominated substituent. Suitable brominated bisphenol A-based compounds are brominated bisphenol A-based polycarbonates represented by the following general formula (II) and brominated bisphenol A-based epoxy resins represented by the following general formula (III).

[0030]

Embedded image

[However, in the equation, k is assumed to satisfy 2 ≦ k ≦ 30, and h is assumed to satisfy 0 ≦ h ≦ 50]

The terminal structure of the brominated bisphenol A-based polycarbonate (II) is preferably a structure end-capped with a 4-t-butylphenyl group or a 2,4,6-tribromophenyl group. Brominated polystyrene represented by the following general formula (IV) and brominated benzyl acrylates represented by the following general formula (V) are preferable as the brominated vinyl polymer flame retardant having a substituent.

[0033]

Embedded image

However, in the formula, p satisfies 5 ≦ p ≦ 300, q satisfies 1 ≦ q ≦ 3, r satisfies 5 ≦ r ≦ 150, and s satisfies 1 ≦ s ≦ 5. It shall be]

The amount of the brominated flame retardant (C) preferably used in the present invention is 5 to 100 parts by weight, preferably 10 to 70 parts by weight, based on 100 parts by weight of the thermoplastic aromatic polyester (A). . If the blending amount is less than 5 parts by weight, the flame retarding effect is not sufficient, and if it exceeds 100 parts by weight, the mechanical strength of the molded product decreases, which is not preferable.

Further, a flame retardant aid may be blended for the purpose of promoting the flame retardant effect. The flame retardant aid has a function of increasing flame retardancy due to a synergistic effect with the brominated flame retardant (C). Suitable flame retardant aids are Sb ₂ O ₃ and / or xNa ₂ O.Sb ₂ O ₅ .yH ₂ O (x = 0 to 1, y
= 0 to 4). The particle size of the flame retardant aid is preferably 0.02 to 5 µ. If desired, those surface-treated with an epoxy compound, a silane compound, an isocyanate compound, a titanate compound or the like can be used.

The blending amount of the flame retardant aid is 0 to 70 parts by weight. It is preferably 1 to 50 parts by weight. In order to effectively impart flame retardance, 20 to 70% by weight relative to the flame retardant
It is preferable to mix them so that If the blending amount exceeds 70 parts by weight, the decomposition of the resin or the compounding agent is promoted, and the characteristics of the molded product may be deteriorated, which is not preferable.

The resin composition of the present invention includes inorganic fillers such as calcium carbonate, titanium oxide, feldspar minerals, clay, white carbon, carbon black, glass beads, and other granular or amorphous fillers; kaolin, Plate-like fillers such as clay and talc; glass flakes,
Flake-like fillers such as mica and graphite; fibrous fillers such as glass fibers, carbon fibers, forastonite, potassium titanate and the like may be added.
From the viewpoint of mechanical strength and heat resistance, it is particularly preferable to contain glass fiber. The content of the inorganic filler is 0 to 20 with respect to 100 parts by weight of the thermoplastic aromatic polyester (A).
0 parts by weight. It is preferably 5 to 150 parts by weight, more preferably 10 to 100 parts by weight.

The resin composition of the present invention contains additives such as a nucleating agent, a lubricant, an antioxidant, an ultraviolet absorber, a heat stabilizer, an antistatic agent and a pigment, as long as the object of the present invention is not impaired. It can be done.

The method for producing the resin composition of the present invention is not particularly limited, and known methods can be adopted.
That is, the thermoplastic aromatic polyester (A), the polyether ester block copolymer (B) and the brominated flame retardant (C) are uniformly mixed using a blender or the like, and then a Banbury mixer, a heating roll, a single screw or 230-360 ° C., preferably 230-290, using a shaft extruder or the like
It can be produced by various methods such as a method of melting and kneading at a temperature of ° C. Alternatively, a method in which the components of the resin composition are preliminarily kneaded, and then kneaded while adjusting to a predetermined mixing ratio later is also possible.

[0041]

The present invention will be described in detail below with reference to examples. In addition, the part in an Example means a weight part. Intrinsic viscosity (IV) is 3
It is a calculated value based on the value measured at 5 ° C. using o-chlorophenol as a solvent. Further, the characteristics of the molded product were measured by the following methods.

Mechanical Properties: Tensile test is ASTM D63
8, bending test to ASTM D790, impact test to A
Compliant with STM D256 (Izod).

Flame retardance: In accordance with the method of Subject 94 (UL-94) of Underwriter Laboratories, USA,
Evaluation is performed using a test piece having a thickness of 0.76 mm.

Hue change: Hue change before and after heat treatment (ΔE)
And ΔE is ΔE = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] in the L ^* a ^* b ^* color system.
It is a numerical value represented by ^1/2 .

The heat treatment conditions are annealing at 170 ° C./96 hours.

The hue change was measured using a color analyzer TC-1800MK-II manufactured by Tokyo Denshoku Co., Ltd.

[Synthesis 1 to 4 of Polyether Ester Block Copolymer] Dimethyl terephthalate and dimethyl isophthalate having the composition shown in Table 1.
Tetramethylene glycol (1.4 times the molar amount of the acid component) and ethylene glycol, and the amount of polyethylene glycol or modified polyethylene glycol described in Table 1,
Tetrabutyl titanate (0.090 mol% with respect to the acid component) was charged as a catalyst into the reactor, and the esterification reaction was performed at an internal temperature of 190 ° C. After about 80% of the theoretical amount of methanol had been distilled off, the temperature elevation was started and the polycondensation reaction was carried out while gradually reducing the pressure. After reaching a vacuum of 1 mmHg or less,
The reaction was continued at 240 ° C for 200 minutes. Next, the antioxidant Irganox 1010 was added to the polyethylene glycol or modified polyethylene glycol in an amount of 5% by weight to complete the reaction. The resulting polyetherester block copolymer was pelletized and used in the examples below.

[0048]

[Table 1]

Example 1 The polyetherester block copolymer obtained by the above Synthesis Example 1 is hereinafter referred to as a polyetherester block copolymer 1.

Polyetherester block copolymer 1, flame retardant, flame retardant aid, glass fiber and other additives were added to polyethylene terephthalate (intrinsic viscosity: 0.51) in a weight ratio shown in Table 2 and 44 mm Using a diameter twin-screw extruder, melt kneading at a cylinder temperature of 260 ° C. and extruding,
Pellets were obtained. A molded piece conforming to the above test method was prepared from the obtained pellets using an injection molding machine, and impact resistance and flame retardancy were examined. Table 2 shows the results.

Thickness 1/16 ″ molded at a mold temperature of 90 ° C.
When the differential scanning calorimetry (DSC) was performed on the test piece of No. 3 at a temperature rising rate of 20 ° C./min using a differential scanning calorimeter, no peak due to crystallization of the amorphous part was observed. It has been revealed that the material has not only good impact resistance but also rapid crystallization and excellent moldability.

[0052]

[Table 2]

[Example 2, Comparative Example 1] Polyether ester block copolymer 1 or elastomer (polybutyl acrylate), flame retardant, flame retardant aid, glass fiber and other additives in the weight ratios shown in Table 3. Blended with polyethylene terephthalate (intrinsic viscosity: 0.63), 44 mm
A pellet was obtained by melt-kneading and extruding at a cylinder temperature of 260 ° C. using a diameter twin-screw extruder. A molded piece conforming to the above test method was prepared from the obtained pellets using an injection molding machine, and impact resistance and flame retardancy were examined. Table 3 shows the results.

The polyester resin composition (Example 2) prepared by blending the polyether ester block copolymer of the present invention was prepared by adding the elastomer (polybutyl acrylate) to the polyester resin composition (Comparative Example 1). In comparison, it can be seen that the impact resistance is remarkably improved.

In Example 2, the moldability and flame retardancy were also good.

[0056]

[Table 3]

[Example 3 and Comparative Example 2] The polyether ester block copolymer 1 or the elastomer (modified polyolefin), the flame retardant, the flame retardant auxiliary, and the weight ratios shown in Table 4 were used.
Glass fibers and other additives were blended with polybutylene terephthalate (intrinsic viscosity: 0.875) and melt-kneaded at a cylinder temperature of 250 ° C. and extruded using a 44 mm diameter twin-screw extruder to obtain pellets. A molded piece conforming to the above test method was prepared from the obtained pellets using an injection molding machine, and impact resistance and flame retardancy were examined. Table 4 shows the results.

The polyester resin composition containing the polyether ester block copolymer of the present invention (Example 3) was compared with the polyester resin composition containing an elastomer (modified polyolefin) (Comparative Example 2). It can be seen that the impact resistance is remarkably improved.

In Example 3, the moldability and flame retardancy were also good.

[0060]

[Table 4]

[Examples 4 to 11] Polyether ester block copolymer 1, flame retardant, flame retardant aid, glass fiber and other additives were added in the weight proportions shown in Table 5 to polyethylene terephthalate (intrinsic viscosity: 0. 63) or polybutylene terephthalate (intrinsic viscosity: 0.875),
Cylinder temperature 250 ° C using a 44 mm diameter twin-screw extruder
Was melt-kneaded and extruded to obtain pellets. Molded pieces were prepared from the obtained pellets using an injection molding machine in accordance with the above test method, and the mechanical properties and flame retardancy were examined. Table 5 shows the results.

In Examples 4 to 11, the moldability and flame retardancy were good.

Throughout Examples 4 to 11, a remarkable improvement in impact resistance was recognized, and it is understood that excellent mechanical properties are exhibited.

In addition to Example 9, it can be seen that even in a composition containing a small amount of glass fiber as a reinforcing material, the composition of the present invention has good mechanical properties. Although Example 11 is a case where polybutylene terephthalate is used as polyester, Example 3
Similarly, in the case of polybutylene terephthalate, good mechanical properties are achieved.

[0065]

[Table 5]

[Example 12, Comparative Example 3] Polyetherester block copolymer 1, flame retardant, flame retardant aid, glass fiber, titanium dioxide (TiO ₂ ) in the weight ratios shown in Table 6.
And other additives are mixed with polyethylene terephthalate (intrinsic viscosity: 0.51), melt-kneaded at a cylinder temperature of 260 ° C. and extruded using a 44 mm diameter twin-screw extruder,
Pellets were obtained (Example 12). For comparison, extruded pellets were obtained by using polyethylene glycol in place of the polyether ester block copolymer 1 and blending in the weight proportions shown in Table 6 (Comparative Example 3). Using the injection molding machine from the resulting pellets to create a molded piece in accordance with the above test method,
The impact resistance and flame retardancy were examined, and the discoloration (hue change (ΔE)) when left at high temperature (170 ° C.) for 96 hours was examined. Table 6 shows the results. In Example 12, the moldability was good.

Since the smaller the ΔE value is, the smaller the hue change is, the polyester resin composition of the present invention has a smaller degree of discoloration than the case where polyethylene glycol is used as a plasticizer for promoting the crystallization of polyethylene terephthalate. It can be seen that the heat resistance is excellent.

As described above, Example 12 and Comparative Example 3 examined here are compositions containing titanium dioxide (TiO ₂ ). Titanium dioxide was added to study the hue change.

In the comparative example 3, the impact strength was greatly reduced by the addition of titanium dioxide, whereas in the composition of the present invention of Example 12, the impact strength was lowered by the addition of titanium dioxide. It can be seen that there are few and sufficient impact resistance.

[0070]

[Table 6]

[0071]

According to the polyester resin composition of the present invention, it is possible to obtain a flame-retardant polyester resin composition having excellent impact resistance and moldability, and having improved heat stability. Heat resistance stability is improved especially in discoloration resistance under high temperature, combined with excellent impact resistance and moldability, particularly advantageous effect when molded into electric, electronic parts, automobile parts, and other machine parts. Exert.

Claims (3)

[Claims] 1. A. First Embodiment Thermoplastic aromatic polyester (A) 10 having an intrinsic viscosity of 0.4 to 1.2 and a melting point of 200 ° C. or higher
0 parts by weight, B. I. 60-100 terephthalic acid for all acid components
an acid component (a) containing 40 to 0 mol% of isophthalic acid, b. A poly (alkylene oxide) glycol component (b) represented by the following general formula (I): [Wherein, X is —H, —CH ₃ , —CH ₂ Cl, —C
H ₂ Br, —CH ₂ I or —CH ₂ OCH ₃ is shown,
n and m are n ≧ 0, m ≧ 0 and 120 ≧ (n + m)
Satisfy ≧ 20] C. 65 to 100 mol of tetramethylene glycol based on all glycol components (excluding (b) component)
%, And a glycol component (c) containing 35 to 0 mol% of ethylene glycol are copolymerized, and the copolymerization amount of the component (b) is 40 to 80 of the total glycol component. 1 to 100% by weight of the polyether ester block copolymer (B)
A polyester resin composition having excellent impact resistance, which is obtained by blending parts by weight. 2. A polyester resin composition having excellent impact resistance according to claim 1, wherein the thermoplastic aromatic polyester (A) is polyethylene terephthalate. 3. The polyester resin composition having excellent impact resistance according to claim 1 or 2, further comprising a bromine-based flame retardant (C). The polyester resin composition having excellent impact resistance, wherein the blending amount is 5 to 100 parts by weight with respect to 100 parts by weight of the thermoplastic aromatic polyester (A).