JPH0459865A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the title composition of good appearance, excellent in flexural modulus and heat resistance, improved in sink mark and warpage, comprising polyethylene terephthalate, a specific ester oligomer, alkali metal salt compound, mica and reinforcing material. CONSTITUTION:The objective composition comprising (A) 10-88.95wt.% of polyethylene terephthalate >=0.35dl/g in intrinsic viscosity, (B) 1-10wt.% of an ester oligomer prepared by polycondensation between a saturated aliphatic dicarboxylic acid (pref. of 2-11C) and saturated aliphatic diol (pref. of 2-7C) wherein at least part of the terminal groups is blocked with an aromatic carboxylic acid, having a number-average molecular weight of pref. 500-8000, (C) 0.05-10wt.% of an alkali metal salt compound as crystal nucleating agent, (D) 5-40wt.% of mica >=50 (pref. 50-300)mum in mean particle diameter, and (E) 5-30wt.% of a reinforcing material (pref. glass fiber pref. >=10 in L/D value).

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a polyester resin composition for molding.

More specifically, the present invention relates to a polyester resin composition that has excellent flexural modulus and heat resistance, has improved sink marks and warpage, and has a good appearance.

(Prior art) Reinforced polyethylene terephthalate resin (hereinafter abbreviated as PET resin) has excellent properties such as heat resistance, mechanical strength, electrical properties, solvent resistance, and weather resistance, and is used for electrical/electronic parts, automobile parts, etc. widely used. Particularly in recent years, the material's good performance has been recognized, and it has come to be widely used for exterior parts.

However, PET resin has the problem of large sink marks and warping.

That is, since PET resin crystallizes slowly, during injection molding, crystallization progresses after the molten resin is completely filled into the mold. For this reason, the material was one in which both the phenomenon of dents and sink marks in the thick parts of the molded product and the warping deformation caused by uneven crystallization occurred at the same time.

Many proposals have been made to improve these problems. For example, Japanese Patent Publication No. 54-4386 proposes blending several tens of weight percent of an amorphous resin such as polycarbonate or polystyrene. Crystalline PE
By blending the non-grade resin into the T resin, sink marks and warping deformation were certainly reduced. However, sacrificing heat resistance by adding non-grade resins would greatly narrow down the range of applications for PET resin, which has excellent heat resistance, and is not a realistic improvement. I can't say that.

JP-A-54-22456 proposes blending glass fiber with a specific inorganic substance. In this proposal, in order to obtain a sufficiently crystallized molded product, the mold temperature must be raised to a very high temperature of 120° C. or higher, resulting in large warping deformation. In addition, since an inorganic material with a fine particle size is used, the effect of suppressing warpage is small, and the reality is that it can only be used as a thick molded product of 3III1 or more.

On the other hand, Japanese Patent Application Laid-Open No. 62-59661 discloses that a specific alkali metal and aliphatic polyester are blended to improve crystallization and lower the mold temperature, and to further eliminate warpage deformation of the grains. It has been proposed to incorporate mica with a large diameter. With this proposal, even if the mold temperature is lowered, sufficient crystallization progresses, excellent heat resistance is achieved, and warping deformation is reduced. However, although heat resistance and warping deformation are satisfactory, sink marks have not been improved.

(Problems to be Solved by the Invention) The present invention provides P, ET that progresses in crystallization even when the mold temperature is lowered, has heat resistance, and has an excellent appearance without sink marks or warping deformation.
The purpose is to capture and supply resin materials.

(Means for Solving the Problems) In order to achieve this object, the present inventors have made extensive studies and found that (A) Polyethylene terephthalate with an intrinsic viscosity of 0.35 or more di/g, 10 to 88.95 weight 1 %, (B) 1 to 10% by weight of an ester oligomer having a polycondensation structure of a saturated aliphatic dicarboxylic acid and a saturated aliphatic diol at least partially end-capped with an aromatic carboxylic acid, (C) an alkali metal salt compound 0 We have discovered that a polyester resin composition consisting of (D) 5-40% by weight of mica having an average particle size of 50 μm or more, and (E) 5-30% by weight of reinforcing material is superior, and has completed the present invention. reached.

The polyethylene terephthalate as component (A) used in the present invention is mainly polyethylene terephthalate obtained by using terephthalic acid or its ester-forming derivative as the acid component and using ethylene glycol or its ester-forming derivative as the glycol component. However, a part of the terephthalic acid component and/or ethylene glycol component may be replaced with a copolymer component.

Examples of such copolymerization components include isotalic acid,
Alkyl-substituted phthalic acids such as phthalic acid, methyltephthalic acid, and methylisophthalic acid; 2゜6-naphthalene dicarboxylic acid, 1.5-naphthalene dicarboxylic acid, 2.7-
Diphenylcarboxylic acids such as phthalene dicarboxylic acid; aliphatic or alicyclic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, decadicarboxylic acid, cyclohexanedicarboxylic acid; trimethylene glycol, tetramethylene glycol, hexa Aliphatic or cycloaliphatic diols such as tyrene glycol, neopentyl glycol, diethylene glycol, 1,4-cyclohexane dimetatool, etc.; Hydroxybenzene II (i2.2-bis(4-hydroxyphenyl)propane such as hydroquinone, resorcinol, etc.) , bis(4-hydroxyphenyl) sulfone, etc.; aromatic diols such as ether diols obtained from bisphenols and glycols such as ethylene glycol; ε-oxycaproic acid, hydroxybenzoic acid, hydroxyethoxybenzoic acid Examples include oxycarboxylic acids such as.

One or more of these copolymerization components can be used, and the proportion thereof is preferably 20 mol% or less based on the total dicarboxylic acids (half of the oxycarboxylic acids are calculated as carboxylic acids) or the total diols. .

Furthermore, a small proportion of a branching component, such as a compound capable of forming a trifunctional ester such as tricarbalic acid, trimellisic acid, or trimellitic acid, or a tetrafunctional ester such as pyromellitic acid, may be copolymerized with the above-mentioned polyethylene terephthalate.

In addition, when using an aromatic hydroxysulfonic acid metal salt as the crystal nucleus side, when compounding the polyethylene terephthalate resin, it may be added and kneaded in the molten state of the resin, or
Alternatively, it can be added during polymerization of polyethylene terephthalate resin, that is, added during esterification reaction, transesterification reaction, or polycondensation reaction, to synthesize and use modified polyethylene terephthalate resin (8°).

The intrinsic viscosity of the polyethylene terephthalate resin (A) used in the present invention is preferably 0.35 a/g or more when measured at 35°C using a solvent containing phenol and chloroform in a 6:4 weight ratio. ,0.45dl
/g or more and o,9di/g or less are more preferable. If the intrinsic viscosity is 0.35 a/g or less, the mechanical strength becomes low, which is not preferable.

The blending amount of component (A) or (8゛) is 10 to 88.95
% by weight, preferably 40 to 80% by weight. If the PET component, which is the resin matrix, is less than 10% by weight, it will become very brittle, and if it is more than 88.95% by weight, it will not be possible to improve mechanical strength or warp deformation.

The ester oligomer (B) used in the present invention is an essential component for promoting crystallization and improving heat resistance when combined with component (C).

It is an ester of a saturated aliphatic dicarboxylic acid and a saturated aliphatic diol, and at least a portion of the terminals must be capped with an aromatic carboxylic acid.

It has a polycondensation structure in which the total carbon number of dicarboxylic acid and diol is 5 to 15, and the terminal of the ester oligomer is 5 to 15.
Preferably, the ester oligomer compound is blocked with 0% or more of an aromatic monocarboxylic acid and has a number average molecular weight in the range of 500 to 8,000.

More preferably, the number average molecular weight is in the range of 500 to 4,000.

In the ester oligomer (B), the ester oligomer in which the sum of carbon numbers of fatty acid and diol is 5 or less is PETp4
Mold stains are likely to occur due to the low molecular weight polyester terephthalic acid in the fat. Furthermore, if the sum of the carbon numbers of the fatty acid and the diol is 15 or more, the compatibility with the PET resin will be insufficient and flow marks will occur at the mold gate.

Furthermore, in the case of an ester oligomer terminal-capped with an aliphatic monocarboxylic acid or an ester oligomer composition having a terminal-blocking ratio of 50% or less, flakes are likely to occur during molding.

Furthermore, if the number average molecular weight is less than 500, mold stains due to gas components may occur in the mold during injection molding, which is undesirable. If the number average molecular weight is 18,000 or more, the mold releasability is not good.

The saturated aliphatic dicarboxylic acid preferably has 2 to 11 carbon atoms, such as oxalic acid, malonic acid, succinic acid,
These include glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, and sebacic acid. The saturated aliphatic diol preferably has 2 to 7 carbon atoms, such as ethylene glycol, propylene glycol, butanediol, and bentanediol. , hexanediol, etc.

Aromatic monocarboxylic acids used for end-capping include, for example, alkyl-substituted aromatic monocarboxylic acids such as benzoic acid and toluic acid; or aryl-substituted aromatic monocarboxylic acids such as biphenylcarboxylic acid; and polycyclic aromatic monocarboxylic acids such as naphthylic acid. There are monocarboxylic acids.

The blending amount of component (B) is 1 to 10% by weight. If the amount is less than 1% by weight, the heat resistance will be low, and if the amount is more than 10% by weight, the improvement in heat resistance will reach saturation and will not only be wasted, but also mechanical strength will decrease, which is not preferable.

The ester oligomer (B) can be synthesized by an esterification method by polycondensation of a corresponding acid or acid anhydride with an alcohol, or by a transesterification method. A synthesis method using an acid halide such as acid chloride is also possible, but it is necessary to sufficiently remove reaction products and unreacted acid halides. Naturally, synthesis using a combination of polycondensation, transesterification, and acid halide methods is also possible.

In the present invention, the alkali metal salt compound (C) used as a crystal nucleating agent can promote crystallization and improve heat resistance even when used alone, but when used in combination with component (B), It has the characteristic that the effect of improving heat resistance is even greater.

Component (C) is (1) an alkali metal salt of aromatic hydroxysulfonic acid represented by the following general formula, or (MO+vAr→SO,M'-辷1 (I)
(In formula (1), M and M are each a metal selected from sodium, potassium, and lithium, Ar is a Hensen ring, and m and n are integers of 1 or 2.) (n-) , (a) a carboxylic acid having an olefinic bond having 2 to 5 carbon atoms, (b) an olefin, (C) an ester of a carboxylic acid having an olefinic bond and a monohydric alcohol, the polymer of (a) above, or (a) and (b) or (a)
, (b) and (C) are alkali metal neutralized salts or partially neutralized salts.

The alkali metal compound (C) of the present invention is (1) or (■
), or a combination of one or more selected from (1) and (II). Further, as the alkali metal constituting the alkali metal salt compound, for example, Na and K are preferable.

As the alkali metal salt (1) of aromatic hydroxysulfonic acid, for example, disodium paraphenolsulfonate is preferable.

In the copolymer metal salt (I[), examples of the carboxylic acid (a) having an olefinic bond include acrylic acid, methacrylic acid, maleic acid, itaconic acid, and fumaric acid.

In addition, examples of the olefin (b) include ethylene,
Examples include propylene, butylene, hexene, and cyclohexene.

Examples of the ester (C) of a carboxylic acid having an olefinic bond and a monohydric alcohol include ethyl acrylate, butyl acrylate, methyl methacrylate, and benzyl methacrylate.

Copolymer metal salt (II) may be (a) alone or (a)
or (b), or a combination of (a), (b), and (C), by radical polymerization or copolymerization to form an alkali metal salt, such as sodium carbonate, potassium hydroxide, or sodium methoxide, without a solvent or It is produced by using a solvent such as xylene or alcohol and, if necessary, neutralizing it under heating.

It can also be produced by polymerization or copolymerization using an alkali metal salt of (a), such as sodium acrylate.

In neutralization, it is easy to produce a copolymer metal salt with a neutralization degree of 70% or less of the total carboxylic acid, but in terms of performance, a copolymer metal salt with a neutralization degree of 80% or more can also be used.

Further, the blending amount of component (C) is 0.05 to IO% by weight. The content is preferably 0.1% by weight or more, and preferably 7% by weight or less. If the amount is less than 0.05% by weight, the improvement in heat resistance will be low, and even if it is added more than 10% by weight, the improvement in heat resistance will reach saturation and not only will it be wasted, but the heat resistance will decrease. or the warpage may become large. Also,
This is not preferable because the Paris length also increases. Moreover, two or more types of component (C) may be blended in combination.

The mica used as component (D) in the present invention is muscovite mica, stripite mica (Marietta trademark), and fluorophlogopite (synthetic mica).

Component (D) is essential for improving warpage and sink marks.

The particle size of the mica used is important, and it is better to use mica with a larger particle size to reduce warping and sink marks, but the brittleness of the resin increases in proportion to the particle size. Therefore, it is not preferable to use mica having an unnecessarily large particle size.

The weight average particle size is preferably 50 to 300 μm, and 50 to 2
More preferably, the thickness is 50 μm.

Regarding the type of mica used, it is not preferable to use mica that releases crystal water or contained water below the temperature of resin kneading and molding (approximately 300°C), and it is undesirable to use mica that releases water of crystallization or contained water below the temperature of resin kneading and molding (approximately 300°C). It must be mica that does not release (equivalent to normal adhering moisture).

The blending amount of component (D) is 5 to 40% by weight based on the total composition weight. More preferably 10% by weight or more and 30% by weight or less. If the blending amount is less than 5% by weight, it is not sufficient to reduce warping deformation, and if it exceeds 40% by weight, not only will it be difficult to mechanically disperse it into polyethylene terephthalate, but the mechanical properties will deteriorate. This is not preferable because it causes deterioration.

When a colored product is required for general use, mica that exhibits an L value of 30 or more when measured with a color difference meter is preferable, and examples of such mica include Mascohycomica and fluorophlogopite (synthetic mica). .

The reinforcing material used as component (E) may be any material that exhibits a reinforcing effect, such as glass fiber, carbon fiber, alumina fiber, alumina fiber, wollastonite, potassium titanate fiber, aramid fiber, etc. In order to achieve this, fibers with L/D (fiber length/fiber diameter) of 10 or more are preferable. Glass fibers and carbon fibers are preferred from the viewpoint of cost and reinforcement effect, and glass fibers are particularly preferred.

The blending amount of component (E) is 5 to 30% by weight, preferably 5 to 20% by weight based on the total composition weight.

I! in proportion to the amount of reinforcing material added! Although the mechanical properties tend to improve, warping deformation also increases, so it is not preferable to add too much. (D) It is important to determine the blending amount while balancing the effects of the component.

The shape of the reinforcing material (E) used in the present invention is 3 to 6
It may be bundled to a length of IIIfil and may or may not be cut. However, after injection molding,
It is necessary that it is uniformly dispersed within the molded product.

The composition of the present invention may also contain a flame retardant, such as a bromine flame retardant and an antimony compound, in an amount sufficient to suppress flammability. Brominated flame retardants include decabromodiphenyl ether, brominated polystyrene,
These include brominated crosslinked polystyrene, brominated polycarbonate, brominated epoxy resin, brominated phenoxy resin, brominated (bisphenol A/siameric acid) polymer, and the like. In addition, antimony compounds include antimony trioxide, antimony pentoxide, triphenylantimony,
Sodium antimonate, etc. When adding flame retardants,
The ratio of bromine flame retardant/antimony compound is 93/7 to 6
B/32 is preferred.

The blending amount is (A + (B) + (C), + (D) +
The total amount of the brominated flame retardant and the antimony compound is preferably 5 to 43% by weight based on the total weight% of (E).

Furthermore, the composition of the present invention may contain heat stabilizers, oxidation stabilizers, ultraviolet stabilizers, lubricants,
A lubricant, a mold release agent, a coloring agent, an inorganic filler, etc. can be added.

EXAMPLES The present invention will be explained below with reference to Examples, but the technical scope of the present invention is not limited by these Examples.

In the examples, "parts" and "%" indicate "parts by weight" and "% by weight."

Examples Reference Example 1 (Synthesis of polyethylene terephthalate (A)) The polymerization of polyethylene terephthalate was carried out using dimethyl terephthalate 1
00 parts of ethylene glycol, 71 parts of ethylene glycol, 0.05 parts of manganese acetate tetrachloride, and 0.05 parts of antimony dioxide were charged into a reactor, and a transesterification reaction was carried out at 180 to 200'C for 3 hours under a nitrogen stream. After distilling off most of the methanol, 0.03 part of trimethyl phosphate was added,
Next, the temperature was raised to 260°C and the pressure was reduced, and a polymerization reaction was carried out at 280'C for 3 hours under a vacuum of 0.5a+mHg.

The resulting polymer was white with a melting point of 260°C (DSC
Perkin Elma type 2C), intrinsic viscosity is 0.70 dl/
It was g.

Reference Example 2 (Synthesis of modified polyethylene terephthalate (8)) Modified polyethylene terephthalate was polymerized using 100 parts of dimethyl terephthalate, 71 parts of ethylene glycol, p-
0.5 part of disodium phenolsulfonate, 0.05 part of manganese acetate tetrachloride, and 0.05 part of antimony dioxide were charged into a reactor, and the mixture was heated at 180 to 200°C under a nitrogen stream for 30 minutes.
The transesterification reaction was carried out for an hour. After most of the methanol was distilled off, 0.03 part of trimethyl phosphate was added, and then the temperature was raised to 260°C and the pressure was reduced, and a polymerization reaction was carried out at 280°C under a vacuum of 0.5w+Hg for 3 hours.

The obtained polymer was white, had a melting point of 255°C (DSC method, Perkin Elma type 2C), and an intrinsic viscosity of 0.68 d1/g.
Met.

The amount of alkali metal salt compound in the modified polyethylene terephthalate is 0.5% by weight.

Reference Example 3: (Synthesis of crystallization accelerator) 100 parts of dimethyl adipate, 141 parts of 1,4-butanediol, and 0.05 parts of tetrapropylisotitanate were charged into a reactor, and the mixture was heated at 160 to 210'C under a N2 stream. After carrying out the transesterification reaction for 3 hours and distilling off most of the methanol, the temperature was raised to 260°C and a polycondensation reaction was carried out under a vacuum of 0.3 m + + + Hg, followed by taking out into a Teflon hat. The resulting polymer had a melting point of 48°C;
Molecular weight is M.

=4.000 (GPC measurement).

Reference Examples 4 to 6 (Synthesis of ester oligomer (B)) The ester oligomer of terminally modified 1,4-butanediol and adipic acid contained 75 parts of 1,4-butanediol, 55,100 parts of adipine, and calcium acetate as a catalyst. After adding 400 ppm and carrying out condensation polymerization at 200°C and normal pressure for 10 hours while distilling off water, 38 parts of methyl benzoate was added and the reaction was further carried out under the same conditions for 15 hours to form polyl,4-butane with terminal henshade. Diol adipate was synthesized.

This synthesized ester oligomer was manufactured using Shimadzu-manufactured rupture LC6.
The molecular weight was measured using a type A liquid chromatograph and TSK Gel 2000 manufactured by Tosoh Corporation as a separation column.

The molecular weight was calculated using polystyrene as a standard substance. The number average molecular weight was 800.

In addition, the OH terminal (OH value) of the ester oligomer, C0
The OH end (acid value) was quantified, and the end blocking rate was calculated from the number average molecular weight, OH value, and acid value.

The terminal blocking rate was 92% (Reference Example 4).

Other types of ester oligomers were also synthesized using the same method except for changing the type and amount of hexamer.

The ester oligomer made by reacting sebacic acid with 1,3-butanediol has a terminal blocking rate of 90% with benzoic acid.
The number average molecular weight by GPC was 2°200 (Reference Example 5).

The ester oligomer made by reacting adipic acid with 1,2-propylene glycol has an end-blocking rate of 9 with benzoic acid.
1%, and the number average molecular weight by GPC was 1,400 (Reference Example 6).

Reference Example 6: (Synthesis of fluorophlogopite) After mixing 40 parts of silicic anhydride, 30 parts of magnesium oxide, 13 parts of aluminum oxide, and 17 parts of potassium silicofluoride, melting at 1.400 to 1,500"C, Furthermore 1.
Synthetic fluorophlogopite [K
Mg3 (Aj2SiC)1°)F2] was obtained.

The obtained synthetic fluorophlogopite ore lump was pulverized to obtain a synthetic fluorophlogopite powder having an average particle size of 90 μm. As a result of measuring the obtained synthetic fluorophlogopite powder with a color difference meter, L
The value was 50.

Note that the average particle diameter was measured according to JIS K-5101.

(Compounding method) Table 1, Table 2, Table 3 from among PET, ester oligomer, crystal nucleating agent, polycarbonate, bromine compound, and antimony compound that have been dried to a moisture content of 1100 pp or less
Put the specified amount of the ingredients shown in into a rotating tumbler.
After rotating for 0 minutes and blending, put it into the hopper of a PCM45 twin-screw co-rotating extruder (manufactured by Ikegai Iron Works).
Extrusion was carried out at a cylinder temperature of 280°C, reinforcing material and mica were added by side feed from the middle of the extruder, mixed and dispersed with the molten resin coming from the hopper side, and strands were extruded from the spinneret. After cooling the extruded strand in water, it was pelletized with a strand cutter to obtain pellets.

(Paris measurement) The compounded polyester resin composition was
The material dried at ℃ for 4 hours was molded using a NN10B injection molding machine manufactured by Japan Steel Works, with the cylinder temperature set at 260 ℃.

The mold used was a weld mold having gates at two locations on both ends of the test piece so that a weld part was formed at the center of the test piece in the shape specified by ASTM D1708. The mold temperature was adjusted to 80'C, and the molding cycle was 10 seconds for injection and 20 seconds for cooling to obtain a predetermined test piece.

Harness was generated in the weld, and the length of the weld was measured using a stereomicroscope.

(Measurement of flexural elasticity and heat resistance temperature) After drying the compounded PET composition at 140°C for 4 hours, it was molded into a C1 mold with a cylinder temperature of 270" using an N70B injection molding machine (Japan Steel Works type). temperature 80°
A 40-second cycle with a C1 injection time of 10 seconds and a cooling time of 20 seconds was used to mold ASTMI Danher and strips. Using the obtained molded product, the flexural modulus was measured by the method specified by ASTM D-790, and the heat distortion temperature (HDT; 1 B, 6 kg/cJ load) was measured by the method specified by ASTM D-256.

(Measurement of sink marks) After drying the compounded PET resin composition at 140°C for 4 hours, use a KC20 injection molding machine (manufactured by Yoro Iron Works).
Using cylinder temperature 270°C1 mold temperature 80°C
A molded article having a boss portion shown in FIG. 1 was produced using a 40-second cycle of 10 seconds of injection time and 20 seconds of cooling time at .degree. Next, as shown in FIG. 2, the depth of the dent at the center on the opposite side of the boss was measured with a dial gauge to determine the size of the sink mark.

(Measurement of warp deformation amount) After drying the compounded PET resin composition at 140°C for 4 hours, using N5-150E injection molding II (manufactured by Toshiba Machine), cylinder temperature 270°C1 mold temperature 80°C 1 injection time 10 seconds, cooling time 20 seconds 40
A flat plate shown in FIG. 3 was formed using a second cycle. Next, as shown in FIG. 4, one side of the flat plate was held down, and the amount of lifting on the other side was measured using a Hyde Gauge (manufactured by Three Layer) to determine the amount of warp deformation.

(Flammability test) Compounded PET resin composition was tested at 140℃ for 4 hours.
After drying for several hours, using a KC20 injection molding machine (manufactured by Yoro Iron Works), the cylinder temperature was 27O℃, the mold temperature was 80℃,
40 second cycle with 10 second injection time and 20 second cooling time.
After forming a strip of 0.75 mm in thickness and the same size as the ASTMI strip, a combustion test was conducted according to the □ method specified by UL94-VO.

Examples 1 to 14, Comparative Examples 1 to 7 By blending the ester oligomer and the alkali metal salt compound, the heat distortion temperature is high even when the mold temperature is 80°C. By using mica in combination, sink marks and warping deformation are suppressed. If the amount of mica is small, sink marks and warping deformation will be large, and if the amount of CF is large, warping deformation will be large. By using an ionomer as an alkali metal salt compound, it was possible to particularly reduce sink marks. The results are shown in Table-1.

Examples 15 to 17 Even when muscovite mica or fluorine phlogopite is used as the mica, results are obtained in terms of strength, heat resistance, sink marks, and warpage deformation.

The results are shown in Table-2.

Examples 19-20 Even if flame retardants are added, Strength, Heat-resistant, Sink, anti It is effective for deformation.

Display the results Shown in 3.

(Effects of the Invention) The PET resin composition of the present invention has improved sink marks, warpage deformation, and firmness without sacrificing the inherent strength characteristics and heat resistance of PET resin, and is therefore a composition that can be used satisfactorily for exterior parts. The fact that it has become a commercial product is extremely beneficial for industry.

[Brief explanation of drawings]

FIG. 1 shows a molded article for measuring sink marks. FIG. 2 is a schematic diagram of FIG. 1 turned upside down and the dent on the opposite side of the boss section is measured as a sink mark. FIG. 3 is a flat plate for measuring warp deformation. FIG. 4 is a schematic diagram when one corner of the flat plate shown in FIG. 3 is held down and the amount of bulge on the opposite side is measured as the amount of warp deformation. Figure 1 Figure 2

Claims (1)

Scope of Claims: (A) 10 to 88.95% by weight of polyethylene terephthalate with an intrinsic viscosity of 0.35 or more dl/g, (B) a saturated aliphatic dicarboxylic acid at least partially end-capped with an aromatic carboxylic acid 1 to 10% by weight of an ester oligomer having a polycondensation structure of and a saturated aliphatic diol, (C) 0.05 to 10% by weight of an alkali metal salt compound, (D) 5 to 40% by weight of mica having an average particle size of 50 μm or more, (E) A polyester resin composition comprising 5 to 30% by weight of reinforcing material.