JPH062867B2 - Reinforced polyester resin composition with excellent impact strength - Google Patents

Description

TECHNICAL FIELD The present invention relates to a reinforced polyester resin composition having improved physical properties, particularly improved impact strength and moldability such as injection molding.

[Conventional technology]

Polyethylene terephthalate (hereinafter sometimes abbreviated as PET) or poly (1,4-butylene terephthalate)
(Hereinafter sometimes abbreviated as PBT) is heat resistance, chemical resistance,
It has excellent mechanical and electrical properties and is used in many industrial products such as fibers and films. In particular, PET reinforced with an inorganic filler such as glass fiber has a thermal property,
Because the mechanical properties are remarkably improved,
Recently, it has been widely used for applications such as engineering plastics.

However, the PET reinforced with such a filler does not always have sufficient impact resistance of the molded product, and the molded product is destroyed during the secondary processing of this molded product, the transportation of the molded product, and the use of the molded product. The problem often arises.

Although various methods are known as means for improving the impact resistance of the filler-reinforced polyester resin, it is general to add an elastic polymer to the filler-reinforced PET or the filler-reinforced PBT.

For example, JP-B-45-26223 discloses a copolymer of vinyl ester of saturated aliphatic monocarboxylic acid and α-olefin as an impact modifier for polyester resin. JP-B-45-26224 discloses a copolymer of an acrylic ester and a conjugated diene as an impact modifier for polyester resin. Japanese Patent Examination Sho 45-
Japanese Patent No. 26225 discloses an ionomer as an impact modifier for a polyester resin. However, it cannot be said that the desired impact strength of the molded product obtained by the above method is sufficiently improved.

Various other methods are known for modifying the impact strength of filler-reinforced polyester resins. For example, JP-A-51
In JP-A-144452, JP-A-52-32045, JP-A-53-117049 and the like, a copolymer composed of α-olefin and α, β-unsaturated carboxylic acid glycidyl ester is blended with a polyester resin. A method is disclosed. In addition to this copolymer, a third
A method in which an ethylene-based copolymer is used in combination as a component of JP-A-58-17148 and JP-A-58-17151
Japanese Patent Laid-Open No. 57-92044 discloses a method of using polyphenylene sulfide in combination.

It is hard to say that sufficient impact strength was obtained even with these methods.

Impact strength can be improved by blending an extremely large amount of elastic material with a filler-reinforced polyester resin (for example, Japanese Examined Patent Publication No. 59).
-30742). However, blending a large amount of elastic material lowers the heat resistance and mechanical strength inherent in polyester.

It is possible to increase the resistance of PET-based filler-reinforced polyester by blending it with PBT.
Known by No. 2360. However, even if PBT is blended with PET-based filler-reinforced polyester, it is not possible to expect an increase in impact strength.

[Problems to be Solved by the Present Invention]

A first object of the present invention is to impart extremely high impact resistance to filler-reinforced polyester (particularly PET) as a molding resin. Another object of the present invention is to provide a filler-reinforced PET resin having excellent moldability such as injection molding.

[Means for solving problems]

That is, the present invention relates to (a) polyethylene terephthalate-based polyester (component (a)) 85 to 15 parts by weight (b) poly (1,4-butylene terephthalate) -based polyester (component (b)) 15 to 85 parts by weight (c) α, β-unsaturated carboxylic acid unit is 1 mol% or more 30
Mol% or less and at least 20 mol% of carboxyl groups
Exists as a 1 to 3 valent metal salt, a metal salt of a copolymer of α-olefin and α, β-unsaturated carboxylic acid and optionally a third vinyl comonomer (component (c)), and
In some cases, a copolymer of (d) α-olefin and α, β-unsaturated carboxylic acid and optionally a third vinyl comonomer ((d) component) (e) fibrous filler is kneaded, Total blending amount of component a) and component (b) 100
The total amount of the components (c) and (d) is 20 to 5 parts by weight.
0 parts by weight and 10 to 150 parts by weight of the component (e), and the ratio of the component (d) to the component (c) ((d)
/ (C)) is a resin composition of 0 or more and 10 or less,
It is intended to provide a resin composition having extremely high impact strength and good moldability.

Surprisingly, the impact strength of the molded product becomes extremely high if a specific amount of PBT-based polyester is used in combination with the PET-based polyester containing the fibrous filler and modified with the specific amount of the above-mentioned (c) component, In some cases, the notched Izod impact strength may reach 20 kg · cm / cm or more.
This is far higher than the impact strength of the filler-reinforced PET-based polyester or the filler-reinforced PBT-based polyester modified with the component (c).

The existence of such a very remarkable synergistic effect is particularly surprising because what is usually expected by a skilled person in the art is that the impact strength gradually increases as the amount of PBT-based polyester added increases. The composition thus obtained was also excellent in fluidity at the time of heat melting, and was a resin suitable for injection molding. What is more surprising in the present invention is that the obtained composition has extremely excellent moldability such as injection molding. That is, it is possible to obtain an injection-molded article having good surface gloss and releasability as a PET resin composition even at a relatively low mold temperature. Further, the above composition is a PET-based reinforced polyester or PBT.
The original properties of the system-reinforced polyester (for example, heat resistance and mechanical strength) are sufficiently retained.

The present invention will be described below.

The PET-based polyester used in the present invention is such that most of the constituent units are ethylene terephthalate units. Therefore, the PET polyester is the original PE
It may contain other copolymerization component within the range that does not impair the physical properties of T. Such copolymerizable components include aromatic dicarboxylic acids such as naphthalene dicarboxylic acid, adipic acid,
Aliphatic dicarboxylic acids such as sebacic acid, diethylene glycol, 1,4-butadiol, neopentyl glycol, diols such as 2-2-bis (4,4'-hydroxyphenyl) propane, polyethylene glycol, poly (tetramethylene oxide) Examples thereof include polyalkylene glycol such as glycol and oxycarboxylic acid such as P-oxybenzoic acid. These copolymerization components are usually within 20 mol%, preferably 10 mol%, and sometimes less than 5% mol%.

Further, the PET-based polyester is a copolymerization component of a trifunctional or higher functional compound such as trimethylolpropane, trimellitic acid, pyromellitic acid and the like, and a monofunctional compound such as lauric acid and the like within a range of being substantially linear. May be contained as. The blending amount of these is usually within the range of 1 mol% or less with respect to the acid component or the diol component.

Of these, the preferred polyester in the present invention is substantially polyethylene terephthalate.

The PET-based ester used in the present invention preferably has an intrinsic viscosity of 0.4 or more from the viewpoint of strength properties of the obtained molded product. The intrinsic viscosity here is 30% in a 1: 1 weight ratio of a phenol / tetrachloroethane mixed solvent.
It is a value measured at ° C.

In the present invention, in addition to the PET-based polyester (component (a)), a specific amount of poly (1,4-butylene terephthalate)
It is characterized in that it is used in combination with polyester. PET-based polyester (component (a)) and ionic copolymer (component (c))
By further combining a predetermined amount of PBT-based polyester (component (b)) in combination with the above, the impact strength thereof shows an unexpectedly large value.

PBT-based polyester used in the present invention ((b)
Component) is such that most of the constitutional units consist of butylene terephthalate units. Therefore, the PBT-based polyester may contain other copolymerization components in a range that does not impair the properties of the original PBT. As such a copolymerizable component, an aromatic dicarboxylic acid such as naphthalene dicarboxylic acid,
Aliphatic dicarboxylic acids such as adipic acid and sebacic acid, diols such as diethylene glycol, ethylene glycol, neopentyl glycol, 2-2-bis (4,4'-hydroxyphenyl) propane, and oxy such as P-oxybenzoic acid. Examples thereof include carboxylic acid. These copolymerization components are usually within 20 mol%, preferably 10 mol%, particularly preferably less than 5 mol%.

Further, the PBT-based polyester is a copolymerization component of a trifunctional or higher functional compound such as trimethylolpropane, trimellitic acid, pyromellitic acid or the like, and a monofunctional compound such as lauric acid or the like within a range of being substantially linear. May be contained as. The blending amount of these is usually within the range of 1 mol% or less with respect to the acid component or the diol component.

Of these, the preferred polyester in the present invention is substantially polybutylene terephthalate. P to use
The intrinsic viscosity of the BT polyester is at least 0.6, preferably 0.8 dl / g or more when measured by the above method. The upper limit is not critical, but is generally about 1.5 dl / g. The intrinsic viscosity of the particularly preferred PBT polyester is in the range of 0.9 to 1.2 dl / g. The amount of PBT polyester used is the PET polyester resin (component (a))
It is 15 to 85 parts by weight with respect to 85 to 15 parts by weight. 1
If it is 5 parts by weight or less, the synergistic effect of using both polyesters is small, and if it is 85 parts by weight or more, only the impact resistance when the PBT polyester alone is modified with the ionic copolymer (component (c)) is obtained. The preferred amount of PBT-based polyester used is 30 to 70 parts by weight.

In the present invention, a metal salt of a copolymer of α-olefin and α, β-unsaturated carboxylic acid and optionally a third vinyl monomer (hereinafter sometimes referred to as an ionic copolymer) is added to the polyester. To be The α-olefin which constitutes the ionic copolymer is ethylene, propylene, etc., and the α, β-unsaturated carboxylic acid is acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc. The vinyl monomer is preferably ethyl acrylate or vinyl acetate. Furthermore, examples of the monovalent to trivalent metal include sodium, potassium, calcium, aluminum and the like, but an alkali metal, particularly sodium is preferable.

These ionic copolymers include α-olefin and α, β-
It can be prepared by copolymerizing an unsaturated carboxylic acid and optionally a third vinyl monomer, and then substituting part or all of the carboxylic acid with a metal salt. Another method for producing an ionic copolymer is to graft-polymerize an α, β-unsaturated carboxylic acid onto a copolymer of α-olefin and optionally a third vinyl monomer, and then replace with a metal salt. There is a way to do it. Still another production method is to copolymerize α-olefin with α, β-unsaturated carboxylic acid ester and optionally a third vinyl monomer, and then saponify the carboxylic acid ester moiety and then replace it with a metal salt. There is also a manufacturing method. Although the ionic copolymer obtained by any method is adopted in the present invention, among these ionic copolymers, those particularly preferably used in the present invention are ethylene and acrylic acid or It is a metal salt of a copolymer composed of ethylene and methacrylic acid. Further, as a metal which gives a cation of the ionic copolymer, an alkali metal, particularly sodium is preferable.

Such ionic copolymers are available from many sources. For example, it is sold under the trade name of Himilan by Mitsui Deyubon Polychemical.

In the above ionic copolymer, it is necessary that the carboxylic acid unit (including the salt form) occupy in the copolymer is 1 mol% or more and 30 mol% or less of all the copolymer units. When it is less than 1 mol%, the effect of the present invention, that is, the impact resistance of the polyester resin is not sufficiently improved. If it exceeds 30 mol%, the ionic copolymer cannot be sufficiently kneaded with the polyester in a short time in the molten state.
A more preferable range of the carboxylic acid unit ratio in the ionic copolymer used in the present invention is 2 mol% or more and 10 mol% or less.

In the present invention, the ionic copolymer need not have all the carboxyl groups present neutralized with metal ions, but at least 20 mol% of all carboxyl groups have been neutralized with metal ions. It is necessary to have
If the neutralization rate is less than 20 mol%, the effect of the present invention that the impact resistance of the polyester resin is improved cannot be sufficiently obtained. The preferred neutralization ratio is 40% or more, and particularly 60 mol% or more.

The neutralization rate is measured by infrared spectrum analysis of the copolymer. That is, νc = 0 absorption intensity of a carboxyl group formed into a salt and νc = 0 of an unneutralized carboxylic acid carboxyl group.
It can be measured by the ratio with the absorption intensity.

A part of the ionic copolymer is converted into a copolymer of α-olefin and α, β-unsaturated carboxylic acid and a third vinyl comonomer (hereinafter referred to as poly (α-olefin) -based copolymer). It is also possible to substitute it. When only the above-mentioned ionic copolymer is used as an impact resistance modifier, impact resistance is improved, but at that time, the coloring of the composition of the present invention at the time of heating is not suitable for use. This is the case. In such a case, a part of the ionic copolymer can be replaced with an unneutralized copolymer (poly (α-olefin) -based copolymer). The amount is up to 10 times that of the component (c).

The total blending amount of the ionic copolymer (c) and the poly (α-olefin) -based copolymer (d) is 100 parts by weight of the total of the PET-based polyester (a) and the PBT-based polyester (b). 20 to 50 parts by weight. If it is less than 20 parts by weight, the object of the present invention of improving impact resistance of the filler-reinforced PET polyester resin cannot be sufficiently achieved. On the other hand, if it exceeds 50 parts by weight, the mechanical properties of the molded article made of the composition of the present invention are different from those of the filler-reinforced PET polyester resin originally, and the rigidity of the molded article is lost. . Particularly preferred ionic copolymers (c) and poly (α-
The total amount of the olefin copolymer (d) is 25 to 40 parts by weight based on 100 parts by weight of the total amount of the PET polyester (a) and the PBT polyester (b).

The α-olefin and the α, β-unsaturated carboxylic acid constituting the poly (α-olefin) -based copolymer (d) are necessary and the third vinyl monomer constitutes the component (c). The monomer is adopted as it is. Also (c)
The component and the copolymer constituting the component (d) may be the same or different.

As the fibrous filler used in the present invention, glass fiber,
Examples include carbon fibers, graphite fibers, metal fibers, silicon carbide fibers, aspest, wollastonite, inorganic fibers such as fibrous potassium titanate, whiskers, and various organic fibers. The preferred fibrous filler is glass fiber, but is not particularly limited, depending on various purposes such as strengthening mechanical properties, imparting heat resistance, imparting conductivity, improving wear characteristics, and improving flame retardancy. Used. Two or more kinds of these fibrous fillers can be mixed and used.

The amount of the fibrous filler compounded is 10 to 1 with respect to 100 parts by weight of the thermoplastic polyester (the total of the components (a) and (b)).
50 parts by weight, preferably 10 to 120 parts by weight. When the blending amount is 10 parts by weight or less, not only the original mechanical strength and heat resistance that are reinforced by PET cannot be obtained, but also the effect of improving the impact resistance, which is the object of the present invention, becomes small. When the amount is 150 parts by weight or more, the fluidity during molding tends to be impaired, and the surface gloss of the molded product tends to be impaired, which is not preferable.

The fibrous filler can be blended as it is, but in order to enhance the affinity and adhesiveness with the polyester resin, the mechanical strength can be further improved by using the one that has been surface treated with an appropriate surface treatment agent. Be improved. Various known surface treatment agents can be used in the present invention, and examples thereof include silane-based, titanate-based, and epoxy-based surface treatment agents.

The above-mentioned polyester, ionic copolymer and poly (α-olefin) -based copolymer are usually obtained in the form of powder or particles (pellet, chip). The desired polyester molded article can be manufactured by melt molding while simply mixing these and the fibrous filler, but once again,
It is also possible to melt-knead the compound to form a pellet or a chip and melt-mold the desired molded article from the pellet or the chip. Accordingly, in the present invention, the mixture of the polyester, the ionic copolymer, and optionally the poly (α-olefin) -based copolymer, and the fibrous filler means that each powder or particle and the fibrous filler are simply Not only a mixed product but also a melt-kneaded product of the both is included.

When blending the polyester with the filler, the ionic copolymer and optionally the poly (α-olefin) -based copolymer, or the polyester, the filler, the ionic copolymer and optionally the poly (α-olefin) -based copolymer When the mixture with the polymer is melt-molded, various additives usually added to polyester, for example, a colorant, a release agent, an antioxidant, an ultraviolet stabilizer, a flame retardant and the like can be added.

The composition of the present invention can be used to produce various molded articles by not only injection molding but also melt molding methods such as extrusion molding. As a molded product obtained by extrusion molding, a molded product having an arbitrary shape such as a rod shape, a sheet shape, a plate shape, a tube shape or a pipe shape can be manufactured. Further, by cutting such an extrusion-molded product, a melt molding material in the form of chips or particles such as chips, pellets or the like can be obtained. Further, according to the injection molding method, an arbitrary shape can be manufactured depending on the shape of the mold. The molded product obtained by any of the molding methods can be easily made into a desired final molded product by secondary molding such as blow molding, drawing molding or vacuum molding. And
Each of the various molded products obtained has extremely high impact strength.

As described above, the composition of the present invention gives a molded article having an extremely high impact strength, which has not been expected with the conventional filler-reinforced PET polyester resin, and therefore makes a great contribution to the field.

Further, the composition of the present invention has excellent flowability, and as a PET resin having a temperature of 100 ° C. or less, the polyester is sufficiently crystallized even when injection-molded in a mold having a relatively low temperature, and has good releasability and surface property. It can be said that it is an excellent resin.

In addition, the PET-based polyester is generally easily hydrolyzed under heat and needs to be sufficiently dried before molding, but the composition of the present invention is insensitive to moisture, and the predrying condition before molding can be relaxed. It also has an advantage.

Hereinafter, the present invention will be described with reference to examples. All parts in the examples are by weight unless otherwise specified.

Examples 1 to 12 and Comparative Examples 1 to 7 Intrinsic viscosity 0.6 which was sufficiently dried in advance with a hot air dryer.
8 PET, PBT with an intrinsic viscosity of 0.85 and sodium salt of ethylene / methacrylic acid copolymer as an ionic copolymer (methacrylic acid (salt) unit content 7 mol
% Neutralization rate 80%) and optionally a poly (α-olefin) -based ethylene / acrylic acid / ethyl acrylate copolymer (acrylic acid unit content 0.5 mol
%, Ethyl acrylate unit content 6 mol%), glass fiber having a length of 3 mm as a chopped strand (manufactured by Nitto Boseki Co., Ltd.), and antioxidant as Phosphite 168 (Ciba Geigy) as shown in Table 1 After mixing and premixing, 40mmφ extruder (8V manufactured by Osaka Seiki Kogyo Co., Ltd.)
(SE-40-28 type) into a hopper and melt-kneaded at a cylinder temperature of 250-275-275-275 ° C (from the hopper side), an adapter temperature of 265 ° C and a die temperature of 265 ° C to obtain a strand. Was cut into pellets. Then, the pellet was subjected to an injection molding machine (V-15-75 manufactured by Nikko Ankelberg Ltd.) adjusted to a cylinder temperature of 240-260-280 ° C., a die temperature of 280 ° C., and a mold temperature of 130 ° C. to have a thickness of 3 mm. Was molded. Table 1 shows the impact strength (I zod method, notched, conforming to JIS K 7110) and tensile strength (conforming to JIS K 7113) of the obtained molded product.

As can be seen from Table 1 Example 3, the PBT content is PET6.
The impact resistance of the composition was maximized at about 40 parts with respect to 0 part, showing a very high value as a filler-reinforced PET resin. When the blending amount of PBT in the total amount of 100 parts of PET and PBT was less than 15 parts, this additive effect was difficult to be seen (Comparative columns 1 and 2). In addition, when the content of PBT is 85 parts or more, the impact strength decreases toward a value only when the glass fiber reinforced PBT alone is modified with an ionic copolymer when the PBT becomes a large excess amount (comparative column). 6,
7).

If the blending amount of the ionic copolymer is less than 20 parts based on 100 parts of the total polyester resin amount of PET and PBT combined, as shown in Comparative Example 3, no matter how the PBT amount is optimized, the impact resistance is improved. I couldn't hope for improvement. Further, as shown in Comparative Example 5, when the blending amount of the ionic copolymer exceeds 50 parts, the system becomes extremely poor in fluidity and cannot be molded.

When the compounding amount of the glass fiber was less than 10 parts with respect to 100 parts of the total polyester resin, as shown in Comparative Example 4, the impact resistance deteriorated.

Even if a part of the ionic copolymer is replaced with an unneutralized copolymer, the impact resistance is not significantly lowered in Examples 10 and 1
It can be understood from Nos. 1 and 12.

Example 13 Sodium salt of ethylene / acrylic acid / ethyl acrylate copolymer (acrylic acid (salt) as ionic copolymer
Unit content 5 mol% Ethyl acrylate Unit content 1 m
ol%, neutralization rate 100%), except that the composition was prepared and molded under the same conditions as in Example 2 to obtain a test piece. The impact strength and measurement results are shown in Table 1.

Example 14 Sodium salt of ethylene / acrylic acid / ethyl acrylate copolymer (acrylic acid (salt) as ionic copolymer
Unit content 3 mol%, ethyl acrylate unit content 3
ethylene / acrylic acid / ethyl acrylate copolymer (acrylic acid unit content 3 mol%, poly (α-olefin) -based copolymer using
A composition was prepared and molded under the same conditions as in Example 2 except that an ethyl acrylate unit content was 3 mol%), and a test piece was obtained. The results of the impact strength measurement are shown in Table 1.

Example 15 Sodium salt of ethylene / acrylic acid copolymer as an ionic copolymer (acrylic acid (salt) unit content 6 mol
%, A neutralization rate of 30%) and an ethylene / acrylic acid copolymer (acrylic acid unit content 3 mol%) was used as the poly (α-olefin) -based copolymer.
A composition was prepared and molded under the same conditions as above to obtain a test piece.
The results of the impact strength measurement are shown in Table 1.

Comparative Examples 8 and 9 A composition was prepared and molded under the same conditions as in Example 13 except that the acrylic acid (salt) unit content in the ionic copolymer was changed as shown in Table 1 to obtain a test piece. As shown in Table 1, it was confirmed that the impact resistance was not improved when the acrylic acid (salt) unit content was 1 mol% or less, and the molding was not possible when the acrylic acid (salt) unit content was 30 mol% or more.

Comparative Example 10 A composition under the same conditions as in Example 13 except that a partially neutralized ethylene / acrylic acid / ethyl acrylate copolymer having an acrylic acid neutralization ratio of 20% or less was used as the ionic copolymer. Was prepared and molded to obtain a test piece. Also in this case, as shown in Table 1, the impact strength was not significantly improved.

Comparative Example 11 In Example 3, by mixing 2 parts by weight of the ionic copolymer and 28 parts by weight of the ethylene / acrylic acid copolymer, a total of the ionic copolymer and the poly (α-olefin) -based copolymer was obtained. A compounding amount was set to 30 parts by weight to obtain a test piece. The results are shown in Table 1, but sufficient impact resistance was not obtained.

Example 16 In Example 3, the mold temperature in injection molding was 110 ° C.
Then, an experiment was conducted in exactly the same manner as in Example 3 except that the injection molding was carried out using a mold whose temperature was controlled so that the oil circulation temperature could be controlled. Also in this case, a molded product having good releasability and excellent surface gloss was obtained, and the crystallinity of the polyester reached 24% by the X-ray method. Also, the impact resistance of the molded product is 2
4 kg · cm / cm (Izot (with notch)), 13
The value was equivalent to that obtained by molding at a mold temperature as high as 0 ° C.

Example 17 and Comparative Example 12 Molded pieces were obtained by the same method as in Example 3 except that the PET which was not dried and contained 0.1% of water was used. The impact strength was 19 kg · cm / cm (Izot (with notch)), and showed a retention of 75% as compared with that of Example 3 using sufficiently dried PET. For comparison, a composition consisting of PET containing 0.1% water and glass fiber was injection-molded by the same method as in Example 3 and the impact resistance was measured, and it was compared with the case where absolutely dried PET was used. The retention rate was 55%. From these examples, it was confirmed that the composition of the present invention retains relatively excellent physical properties even when molded using PET in a water-containing state.

Examples 18 to 20 and Comparative Examples 13 to 15 Polyethylene terephthalate polyester obtained by copolymerizing polyethylene glycol having an average molecular weight of 1000 as a glycol component in place of PET (copolymerization amount is 10 parts by weight with respect to 100 parts by weight of ethylene terephthalate component, that is, Molded pieces were obtained in substantially the same manner as in Example 3 and Comparative Examples 2 and 6 except that the ratio of polyethylene glycol to all glycol components was 1.9 mol%. The impact strength is shown in Table 2.

Example 21 In Example 19, the mold temperature in injection molding was 90 ° C.
An experiment was conducted in exactly the same manner as in Example 19 except that the injection molding was carried out using a mold whose temperature was controlled so that the oil circulation temperature could be adjusted. Also in this case, a molded product having good releasability and good surface gloss was obtained, and the crystallinity of the polyester reached 22% by the X-ray method. Also, the impact resistance of the molded product is 2
2 kg · cm / cm (Izotsu (with notch)), 13
The value was equivalent to that obtained by molding at a mold temperature as high as 0 ° C.

Example 22 and Comparative Example 16 Molded pieces were obtained in the same manner as in Example 19 except that the PEG-1000 copolymerized polyester used in Example 19 was an undried polyester containing 0.1% of water. . The impact strength was 17 kg · cm / cm (Izot (with notch)), and the retention rate of 75% was shown in comparison with that of Example 2 using the sufficiently dried copolymerized polyester. For comparison, the copolyester containing 0.1% of water was injection molded in the same manner as in Example 19 and the impact resistance was measured. As a result, the retention rate was 55% as compared with the case of using the absolutely dried copolyester. Atsuta From these examples, it was confirmed that the composition of the present invention retains relatively excellent physical properties even when it is molded using the water-containing copolyester.

〔The invention's effect〕

As described above in the examples, the present invention is a polyester resin modified with extremely high impact strength which is not expected with the conventional filler-reinforced PET polyester resin without deteriorating other physical properties. It is intended to provide a composition.
Furthermore, by using the composition of the present invention, an injection-molded article having good mold releasability and excellent surface gloss can be obtained even if a mold having a low mold temperature of about 100 ° C. is used as PET. Also,
Generally, the PET-based polyester is easily hydrolyzed when heated and needs to be sufficiently dried before molding. However, the composition of the present invention is relatively insensitive to moisture, and the predrying conditions before molding can be relaxed. Have.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Okuno Kenji Okuno, Kuraray Co., Ltd. 1621 Sakata, Kurashiki City, Okayama Prefecture (56) Reference JP-A-53-81530 (JP, A)

Claims (6)

[Claims] 1. Polyethylene terephthalate-based polyester (a) 85 to 15 parts by weight (b) Poly (1,4-butylene terephthalate) -based polyester ((b) component) 15 to 85 parts by weight (c) ) α, β-unsaturated carboxylic acid unit is 1 mol% or more 30
Mol% or less and at least 20 mol% of carboxyl groups
Exists as a 1 to 3 valent metal salt, a metal salt of a copolymer of α-olefin and α, β-unsaturated carboxylic acid and optionally a third vinyl comonomer (component (c)), and
In some cases, a copolymer of (d) α-olefin and α, β-unsaturated carboxylic acid and optionally a third vinyl comonomer ((d) component) (e) fibrous filler is kneaded, Total blending amount of component a) and component (b) 100
The total amount of the components (c) and (d) is 20 to 5 parts by weight.
0 parts by weight and 10 to 150 parts by weight of the component (e), and the ratio of the component (d) to the component (c) ((d)
/ (C)) is 0 or more and 10 or less. 2. The resin composition according to claim 1, wherein the component (a) is polyethylene terephthalate. 3. The resin composition according to claim 1, wherein the component (c) is an alkali metal salt of a copolymer of ethylene and acrylic acid or methacrylic acid. 4. The resin composition according to claim 1 or 3, wherein the monovalent to trivalent metal constituting the component (c) is sodium. 5. The resin composition according to claim 1, wherein the component (b) is poly (1,4-butylene terephthalate). 6. The resin composition according to claim 1, wherein the component (e) is glass fiber.