JPH0116864B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a resin composition having improved physical properties, especially improved impact strength, and excellent molding processability such as injection molding. [Prior Art] Polyethylene terephthalate (hereinafter referred to as PET) has excellent heat resistance, chemical resistance, mechanical properties, electrical properties, etc., and is used in many industrial products such as fibers and films. In particular, PET reinforced with inorganic fillers such as glass fiber has thermal properties,
Since it has significantly improved mechanical properties, it has been widely used in engineering plastics and the like in recent years. However, PET molded articles do not necessarily have sufficient impact resistance, and problems often arise in which the molded articles break during secondary processing, transportation, and use. Its impact resistance is inferior to that of poly(1,4-butylene terephthalate) (hereinafter sometimes abbreviated as PBT), which is the same thermoplastic polyester. A common way to improve the impact resistance of PET is to add some type of elastomeric polymer to PET. For example, Japanese Patent Publication No. 45-26223 discloses a copolymer of a vinyl ester of a saturated aliphatic monocarboxylic acid and an α-olefin as an impact modifier for polyester resin. Japanese Patent Publication No. 45-26224 discloses a copolymer of acrylic acid ester and conjugated diene as an impact modifier for polyester resin. Japanese Patent Publication No. 45-26225 discloses an ionomer as an impact modifier for polyester resin. However, it cannot be said that the molded articles obtained by the above method have sufficiently improved impact strength. Various other methods are known for modifying the impact strength of polyester resins. For example, Tokukai Akira
51-144452, JP-A-52-32045, JP-A-53-117049, etc., blend a copolymer consisting of α-olefin and α,β-unsaturated carboxylic acid glycidyl ester with polyester resin. A method is disclosed. In addition to this copolymer, a method of using an ethylene copolymer as a third component is disclosed in JP-A-58-17148 and JP-A-Sho.
JP-A-57-92044 discloses a method in which polyphenylene sulfide is used in combination with JP-A No. 58-17151. Even with these methods, it cannot be said that sufficient impact strength was obtained. Aromatic polycarbonate resin is well known as the resin with the highest impact resistance among plastics, but by blending it with PET,
Examples of attempts to modify the impact resistance of PET have existed for a long time (Special Publication No. 14035, 1973). Recent patents, such as US Pat. No. 4,257,937, disclose a combination of polyacrylate resins and aromatic polycarbonate resins as impact strength modifiers for polyester resins. This method made it possible to obtain significantly higher impact strength. Furthermore, in Japanese Patent Application Laid-open No. 59-161460,
It was shown that when modifying the impact strength of PET with polyacrylate resin and aromatic polycarbonate resin, if an effective amount of poly(1,4-butylene terephthalate) is used in combination, the impact resistance is further improved dramatically. Ta. However, even though the impact strength (Izod impact strength) obtained with this method is the highest value,
The value is only close to that of the PBT/polyacrylate resin/aromatic polycarbonate resin composition, but has not reached a higher value. [Problems to be solved by the invention] The first object of the present invention is to solve the problem as an injection molding resin.
The purpose is to provide extremely high impact resistance to PET. Another object of the present invention is to improve the moldability of PET resin compositions in injection molding and the like. [Means for Solving the Problems] That is, the present invention consists of (a) polyethylene terephthalate polyester (component (a)) 85 to 15 parts by weight, (b) poly(1,4-butylene terephthalate) polyester ((b) Ingredients) 15 to 85 parts by weight (c) α,β-unsaturated carboxylic acid units are 1 mol% or more and 30 mol% or less, and at least 20 mol% of the carboxyl groups are present as mono- to trivalent metal salts, A metal salt of a copolymer of an α-olefin and an α,β-unsaturated carboxylic acid and optionally a third vinyl comonomer (component (c)), and (d) a block copolyether ester elastomer (component (d)). The total amount of ingredients (c) and (d) is
20 parts per 100 parts by weight of the total amount of ingredients (a) and (b)
~50 parts by weight, and the ratio of the amount of component (d) to component (c) ((d)/(c)) is 10 or less, and has extremely high impact strength. A resin composition is provided. Surprisingly, by combining a specific amount of PBT polyester with PET polyester, the above (c) and
If modified with a specific amount of component (d), the impact strength of the molded product will be extremely high, and in some cases, the notched isot impact strength can reach 110 Kg·cm/cm or more. This is PET polyester or
The impact strength is much higher than that of the composition made by modifying PBT polyester with components (c) and (d) above, and it also exceeds aromatic polycarbonate resin, which is known as a resin with excellent impact resistance. . The existence of such a highly significant additive effect was particularly surprising since one skilled in the art would normally expect that impact strength would gradually increase with increasing amount of PBT-based polyester added.
Furthermore, what is surprising about the present invention is that the composition thus obtained has extremely excellent molding processability such as injection molding. That is, as a PET resin composition, injection molded products with good surface gloss and mold releasability can be obtained even at relatively low mold temperatures. The present invention will be explained below. In the PET polyester used in the present invention, at least 80 mol% of the constituent units are ethylene terephthalate units. Therefore, applicable
The PET polyester may contain less than 20 mol% of other copolymer components. Such copolymerizable components include aromatic dicarboxylic acids such as isophthalic acid and naphthalene dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, diethylene glycol, 1,4-butanediol,
Neopentyl glycol, 2-2-bis(4,
Examples include diols such as 4'-hydroxyphenyl)propane, polyalkylene glycols such as polyethylene glycol and poly(tetramethylene oxide) glycol, and oxycarboxylic acids such as p-oxybenzoic acid. In addition, within the range where the PET polyester is substantially linear, trifunctional or higher functional compounds such as trimethylolpropane, trimellitic acid, pyromellitic acid, etc., and monofunctional compounds such as lauric acid, etc. can be copolymerized. It may be contained as. The blending amount of these components is usually 1 mol % or less based on the acid component or diol component. Among 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 the strength properties of the molded product obtained. The intrinsic viscosity here is a value measured at 30° C. in a mixed solvent of phenol/tetrachloroethane at a weight ratio of 1:1. The present invention is characterized in that a specific amount of poly(1,4-butylene terephthalate) polyester is used in addition to PHT polyester (component (a)). A combination of PET polyester (component (a)), ionic copolymer (component (c)), block copolyetherester elastomer (component (d)), and a predetermined amount of PBT polyester (component (b))
By combining these, the impact strength shows an unexpectedly large value. In the PBT polyester (component (b)) used in the present invention, at least 80 mol% of the constituent units are butylene terephthalate units.
Therefore, the PBT polyester may contain less than 20 mol% of other copolymer components. Such copolymerizable components include aromatic dicarboxylic acids such as isophthalic acid and naphthalene dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, diethylene glycol, ethylene glycol, neopentyl glycol, and 2-2-bis( Examples include diols such as 4,4'-hydroxyphenyl)propane, and oxycarboxylic acids such as p-oxybenzoic acid. In addition, within the range where the PBT polyester is substantially linear, trifunctional or higher functional compounds such as trimethylolpropane, trimellitic acid, pyromellitic acid, etc., and monofunctional compounds such as lauric acid, etc. can be copolymerized. It may be contained as. The blending amount of these components is usually 1 mol % or less based on the acid component or diol component. Among these, the preferred polyester in the present invention is substantially polybutylene terephthalate. The intrinsic viscosity of the PBT polyester used is at least 0.6, preferably at least 0.6 when measured by the method described above.
It is 0.8 dl/g or more. The upper limit is not important, but
Generally about 1.5 dl/g. The specific particle size of the particularly preferred PBT polyester is 0.9 to 1.2 dl/g. The amount of PBT polyester used is 15 to 85 parts by weight relative to 85 to 15 parts by weight of PET polyester (component (a)). If it is less than 15 parts by weight, there will be little synergistic effect from the combination of both polyesters, and if it exceeds 85 parts by weight,
Impact resistance can only be obtained when PBT polyester alone is modified with an ionic copolymer (component (c)) and a block copolyether ester elastomer (component (d)). A particularly preferable amount of PBT polyester to be used is 30 to 70 parts by weight. In the present invention, α-olefin and α,β-
A metal salt of an unsaturated carboxylic acid and optionally a copolymer with a third vinyl monomer (hereinafter sometimes referred to as ionic copolymer) is added to the polyester. The α-olefin constituting the ionic copolymer includes ethylene, propylene, etc.
As α,β-unsaturated carboxylic acids, acrylic acid,
methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc., and as a third vinyl monomer, ethyl acrylate, vinyl acetate, etc., and further 1 to 3
Preferred valent metals include sodium, potassium, calcium, aluminum, and the like. These ionic copolymers are produced by copolymerizing α-olefin, α,β-unsaturated carboxylic acid, and optionally vinyl monomer, and then replacing part or all of the carboxylic acid with a metal salt. can be manufactured. 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, followed by substitution with a metal salt. There is a way to do it. Still another production method involves copolymerizing α-olefin, α,β-unsaturated carboxylic acid ester, and optionally a third vinyl monomer, and then saponifying the carboxylic acid ester portion and then replacing it with a metal salt. There is also a method of manufacturing it.
Ionic copolymers obtained by any method can be employed in the present invention, but among these ionic copolymers, those that are particularly preferably used in the present invention are ethylene and acrylic acid or It is a metal salt of a copolymer consisting of ethylene and methacrylic acid. Further, as the metal providing the cation of the ionic copolymer, an alkali metal, particularly sodium, is preferable. There are many sources of such ionic copolymers. For example, it is sold under the trade name Himilan by Mitsui-Dupont Polychemicals. In the above ionic copolymer, it is necessary that the carboxylic acid units (including in the form of salt) occupying the copolymer account for 1 mol% or more and 30 mol% or less of the total copolymer units. If it is less than 1 mol%,
The effect of the present invention, that is, the improvement in the impact resistance of the polyester resin is not sufficiently achieved. If it exceeds 30 mol%, the ionic copolymer cannot be sufficiently kneaded into the polyester in a short time in a molten state. A more preferable range of the proportion of carboxylic acid units 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 does not require that all carboxyl groups present be neutralized by metal ions, but at least 20 mol% of all carboxyl groups are neutralized by metal ions. It is necessary that the If the neutralization rate is less than 20 mol%, the effect of the present invention of improving the impact resistance of the polyester resin cannot be sufficiently achieved. A preferable neutralization rate is 40% or more, particularly 60 mol% or more. Note that the neutralization rate is measured by infrared spectrum analysis of the copolymer. That is, it can be measured by the ratio of the νc=0 absorption intensity of the carboxyl group in the form of a salt and the νc=0 absorption intensity of the unneutralized carboxylic acid carboxyl group. In the present invention, an ionic copolymer is used in combination with a block copolyetherester elastomer. The block copolyether ester elastomer used in the present invention as component (d) is 60 mol%
The above is composed of polyester made of polyalkylene terephthalate and poly(alkylene oxide) glycol with a molecular weight of 400 to 6,000, and the poly(alkylene oxide) glycol component contains 10 to 80% of the weight of the elastomer. It is. The polyalkylene terephthalate that constitutes the hard segment of this block copolyether ester elastomer is a polymer whose main acidic component is terephthalic acid and whose main diol component is aliphatic glycol having 2 to 10 carbon atoms, but dicarboxylic acids other than terephthalic acid Alternatively, it may be a copolymer of glycols other than aliphatic glycols having 2 to 10 carbon atoms up to a total of 40 mol%. These copolymerizable components include:
Aliphatic, alicyclic or aromatic dicarboxylic acids such as adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, etc.; neopentyl glycol, 1,4-cyclohexanedimethanol , 1,4-cyclohexane diethanol,
Mention may be made of aliphatic, alicyclic or aromatic diols such as 1,4-benzenedimethanol, 1,4-benzenedimethanol and the like. Others, p.
- Oxy acids such as oxybenzoic acid and p-hydroxyethoxybenzoic acid can also be copolymerized. The other component of the block copolyether ester elastomer, the poly(alkylene oxide) glycol that constitutes the soft segment, is, for example, poly(ethylene oxide).
Single glycols such as glycol, poly(propylene oxide) glycol, poly(tetramethyl oxide) glycol; random combinations of ethylene oxide and propylene oxide, or
Copolymerized glycols such as block copolymerized polyglycol, random or block copolymerized polyglycol of tetrahydrofuran and 2,2-dimethyloxetane, and mixtures of two or more of the above glycols can be mentioned. Poly(alkylene oxide) in the present invention
The number average molecular weight of glycol is 400 to 6,000, preferably 500 to 4,500; if the molecular weight is too large, the poly(alkylene oxide) glycol unit itself becomes crystalline, resulting in poor impact resistance,
It no longer contributes to improving wear resistance, and on the contrary, the molecular weight
Similarly, if it is less than 400, it will not contribute to improving impact resistance and abrasion resistance. The content of poly(alkylene oxide) glycol in the block copolyetherester elastomer must be 10 to 80%, preferably 15 to 70%, of the weight of the elastomer. If it exceeds 80% by weight, the hard segment properties of the elastomer will almost disappear, resulting in poor compatibility with PET polyester and PBT polyester. Furthermore, if it is less than 10% by weight, the poly(alkylene oxide) glycol units are too small, resulting in a low modulus of elasticity and no longer contributing to improvement in impact resistance. Preferred specific examples of the block copolyether ester elastomer as component (d) in the present invention include polyester components (hard segment components).
Examples include elastomers in which 60 mol% or more of the polyester is composed of polybutylene terephthalate, and the polyether component (soft segment component) is polyether glycol composed of poly(tetramethylene oxide) glycol. In general, the block copolyether ester elastomer of the component (d) in the present invention has excellent miscibility with PBT, but in particular, the elastomer consisting of the above-mentioned components has good miscibility with the modified PET polyester and PBT. is extremely good. The block copolyether ester elastomer of the present invention is produced by a conventional production method. For example, a method in which terephthalic acid, a low molecular weight diol, and a poly(alkylene oxide) glycol are directly esterified; a method in which dialkyl terephthalate and a low molecular weight diol are transesterified, and then poly(alkylene oxide) glycol is added and polycondensed. Either method may be used. In addition, when producing elastomers, catalysts, various stabilizers,
Modifiers, pigments, etc. can be used as necessary. There are many sources of such block copolyetherester elastomers. For example, it is sold by Toyobo Co., Ltd. under the trade name Pelprene. Block copolyether ester elastomer (component (d)) is used in combination with an ionic copolymer, but the blending ratio is such that the amount of component (d) does not exceed 10 times the weight of the number of parts of component (c) blended. . If the amount of component (c) is too small, the objective of the present invention, which is to improve impact resistance, cannot be achieved. As long as high impact resistance, which is one of the objects of the present invention, can be maintained, it is preferable for the composition to have a higher blending ratio of component (d) to component (c). The ratio of the amount of component (d) to component (c) ((d)/(c)) is preferably in the range of 0.5 to 5. The total amount of these ionic copolymer (c) and block copolyether ester elastomer (d) is 20 to 50 parts by weight based on the total of 100 parts by weight of PET polyester (a) and PBT polyester (b). It is. If it is less than 20 parts by weight, the object of the present invention, which is to improve the impact resistance of PET polyester resin, cannot be sufficiently achieved. If the amount exceeds 50 parts by weight, the mechanical properties of the molded article made from the composition of the present invention will differ from those of the PET polyester resin, for example, the molded article will lose its rigidity. The particularly preferred total amount of ionic copolymer (c) and block copolyether ester elastomer (d) is the total amount of PET polyester resin (a) and PBT polyester (b).
The amount is 25 to 40 parts by weight per 100 parts by weight. The above-mentioned polyesters and ionic copolymers and block copolyetherester elastomers are usually obtained in powder or particulate form (pellets, chips). It is possible to manufacture the desired polyester molded product by simply mixing and melt-molding these materials, but it is also possible to once melt-knead the mixture to form pellets or chips, and then form the desired molded product from the pellets or chips. It can also be melt-molded. Therefore, in the present invention, the mixture of polyester, ionic copolymer, and block copolyether ester elastomer includes not only a mixture of the powders or particles of each, but also a mixture of the two. Ru. Various additions that are normally added to polyester when compounding the polyester with the ionic copolymer and the blocked copolyether ester elastomer or when melt molding a mixture of the polyester and the ionic copolymer and the blocked copolyether ester elastomer. Agents such as colorants, mold release agents, antioxidants, ultraviolet stabilizers, flame retardants, etc. may also be added. The composition of the present invention can be used to produce various molded products by melt molding methods such as extrusion molding and injection molding. Molded products obtained by extrusion molding can be of any shape, such as fiber, rod, film, sheet, plate, tube, or pipe, depending on the shape of the molding die. . Further, by cutting the extruded product, small pieces such as chips and pellets or particulate materials for melt molding can be obtained. Moreover, according to the injection molding method, it is possible to manufacture products of arbitrary shapes by changing the shape of the mold. The molded product obtained by any of the molding methods can be further easily made into a desired final molded product by secondary molding processing such as blow molding, drawing molding, or vacuum forming. All of these various molded products have extremely high impact strength. As described above, the composition of the present invention provides molded products with extremely high impact strength, which was not expected with conventional PET polyester resins.
His contribution to this world is extremely large. Furthermore, even when the composition of the present invention is injection molded in a mold at a relatively low temperature for a PET resin, around 100°C, the polyester crystallizes sufficiently, giving molded products with good mold releasability and excellent surface properties. It can be said that this resin has excellent moldability. Furthermore, thermoplastic polyesters such as PET and PBT are generally susceptible to hydrolysis when heated and need to be thoroughly dried before molding, but the composition of the present invention is insensitive to moisture and requires pre-drying before molding. It also has the advantage of being able to relax conditions. The present invention will be explained below with reference to Examples. All parts in the examples are by weight unless otherwise specified. Reference Example A (Synthesis example of block copolyether ester) 136.0 parts of dimethyl terephthalate, 152.1 parts of poly(tetramethylene oxide) glycol having a number average molecular weight of approximately 1000, and 1,4-butanediol
94.5 parts were charged into a reaction vessel equipped with a stirrer together with 0.10 parts of titanium tetrabutoxide catalyst, and heated at 210°C for 2 hours to distill methanol. After almost the theoretical amount of methanol had distilled out, 4.0 parts of Irganox 1010 (trade name, Ciba Geigy, antioxidant) was added to the reaction mixture, and the temperature was raised to 250°C and gradually heated over 1 hour. The pressure inside the system was lowered to 0.3 mmHg. Polymerization was carried out under these conditions for 2 hours. The intrinsic viscosity of the obtained polymer was 0.9. Examples 1 to 9 and Comparative Examples 1 to 5 A predetermined amount of PET with an intrinsic viscosity of 0.68, which had been thoroughly dried in a hot air dryer, was
Ethylene/as PBT and ionic copolymer
Sodium salt of methacrylic acid copolymer (methacrylic acid (salt) unit content 7 mol% neutralization rate 80%) and the polymer prepared in Reference Example A as a block copolyether ester elastomer and Phosphite 168 = trade name (Ciba Geigy) as an antioxidant. ) as shown in Table 1.
8VSE-40-28 type) and extruded while melt-kneading 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. Next, the pellets were heated at a cylinder temperature of 240-260-280℃, a die temperature of 280℃,
3 mm thick using an injection molding machine (V-15-75 type manufactured by Nikko Ankelberg Co., Ltd.) with a mold temperature of 130°C.
A test piece was molded. Table 1 shows the impact strength (Izod method, notched, based on JIS K 7110) of the obtained molded product. As can be seen from the examples in Table 1, the PBT content is
At about 40 parts per 60 parts of PET, the composition reached its maximum impact resistance, showing an extremely high value exceeding that of aromatic polycarbonate resin. PET
and the amount of PBT in 100 parts of total PBT is
Below 20 parts, this synergistic effect became difficult to see (Comparative Example 1). In addition, if the number of copies exceeds 85, PBT
When the amount of PBT became a large excess, the impact strength decreased toward the value obtained by simply modifying PBT alone with an ionic copolymer (Comparative Examples 4 and 5). If the amount of ionic copolymer blended is 20 parts or less per 100 parts of the total polyester resin including PET and PBT, impact resistance will be insufficient even if the amount of PBT is optimized, as shown in Comparative Example 3. There was no hope for improvement. Even if the combined amount of ionic copolymer and block copolyether ester is 30 parts per 100 parts of total polyester resin, the ratio of ionic copolymer to block copolyether ester is 1/1. If it is less than 10, high impact resistance cannot be obtained (Comparative Example 2). Even if this proportion becomes large and almost all of the copolymer is an ionic copolymer, high impact resistance can be expected (Example 4). It is desirable to use both in combination in order to improve the fluidity of the resin. Example 10 Sodium salt of ethylene/acrylic acid/ethyl acrylate copolymer as ionic copolymer (acrylic acid (salt) unit content 5 mol%, ethyl acrylate unit content 1 mol%, neutralization rate 100%) 15
A composition was prepared under the same conditions as in Example 2 except that 15 parts of the block copolyether ester elastomer was used, and the composition was molded to obtain a test piece. Table 1 shows the impact strength and measurement results. Example 11 Sodium salt of ethylene/acrylic acid/ethyl acrylate copolymer as ionic copolymer (acrylic acid (salt) unit content 3 mol%, ethyl acrylate unit content 3 mol%, neutralization rate 100%) 20
A composition was prepared under the same conditions as in Example 3 except that 10 parts of the block copolyether ester elastomer was used, and the composition was molded to obtain a test piece. The impact strength measurement results are shown in Table 1. Example 12 Other than using 20 parts of sodium salt of ethylene/acrylic acid copolymer (acrylic acid (salt) unit content 6 mol%, neutralization rate 30%) and 10 parts of block copolyether ester elastomer as ionic copolymer A composition was prepared and molded under the same conditions as in Example 3 to obtain a test piece. The impact strength measurement results are shown in Table 1. Comparative Examples 6 and 7 A composition was prepared and molded under the same conditions as in Example 10, except that the content of acrylate units in the ionic copolymer was changed as shown in Table 1, and test pieces were obtained. Table 1
As shown in , the acrylate unit content is
It was confirmed that if it is less than 1 mol%, the impact resistance will not be improved, and if it is more than 30 mol%, molding will not be possible. Comparative Example 8 Acrylic acid neutralization rate as ionic copolymer is 20
A composition was prepared under the same conditions as in Example 9, except that a partially neutralized ethylene/acrylic acid/ethyl acrylate copolymer having a concentration of 1% or less was used, and the composition was molded to obtain a test piece. In this case as well, as shown in Table 1, no significant improvement in impact strength was observed.

[Table] Example 13 In Example 3, the mold temperature during injection molding was
An experiment was carried out in exactly the same manner as in Example 3, except that injection molding was carried out using a mold whose temperature was lowered to 110°C, which was the temperature at which the oil circulation temperature could be controlled. In this case as well, a molded article with good mold releasability was obtained, and the crystallinity of the polyester reached 26% according to the X-ray method. The impact resistance of the molded product was also 109 kg·cm/cm (isot (notched)), which is equivalent to that of a molded product obtained by molding at a high mold temperature of 130°C. Example 14 and Comparative Example 9 Molded pieces were obtained in exactly the same manner as in Example 3, except that in Example 2, undried PET containing 0.1% water was used. Impact strength is 69Kg・cm/
cm (isot (notched)), and showed a retention rate of 71% compared to that of Example 2, which used sufficiently dried PET. For comparison, PET containing 0.1% water was injection molded using the same method as in Example 2, and its impact resistance was measured. The retention rate was 55% compared to when bone dry PET was used. From these examples, it was confirmed that the composition of the present invention maintains relatively excellent physical properties even when molded using hydrated PET. Examples 15 to 18 and Comparative Examples 10 to 11 In Examples 1 to 9, polyethylene terephthalate polyester copolymerized with polyethylene glycol having an average molecular weight of 1000 as a glycol component instead of PET (the amount of copolymerization was 100 parts by weight of the ethylene terephthalate component) Molded pieces were obtained in the same manner as in Examples 1 to 9, except that 10 parts by weight of polyethylene glycol was used (ie, the proportion of polyethylene glycol in the total glycol component was 1.9 mol %). Table 2 shows the impact strength.
Shown below.

[Table] Combined polyethylene terephthalate polyester
b) Table 1 Reference Example 19 In Example 18, the mold temperature during injection molding was
An experiment was carried out in exactly the same manner as in Example 18, except that injection molding was performed using a mold whose temperature was lowered to 90°C, which allowed the water circulation temperature to be controlled. In this case as well, a molded product with good mold releasability was obtained, and the polyester crystallinity was 24%.
had reached. In addition, the impact resistance of the molded product is 105Kg.
cm/cm (Izot (with notch)) and 130℃
It showed a value equivalent to that obtained by molding at a high mold temperature. [Effects of the Invention] As shown in the examples above, the present invention
The present invention provides a modified polyester resin composition that exhibits extremely high impact strength, which was unexpected for PET polyester resins. Furthermore, by using the composition of the present invention, injection molded products can be obtained with good mold releasability even when using a mold with a mold temperature of around 100° C., which is low for PET. In addition, PET is generally susceptible to hydrolysis when heated and requires sufficient drying before molding, but the composition of the present invention is relatively insensitive to moisture and has the advantage of being able to relax pre-drying conditions before molding. have

Claims (1)

[Scope of Claims] 1 (a) Polyethylene terephthalate polyester (component (a)) 85 to 15 parts by weight (b) Poly(1,4-butylene terephthalate) polyester (component (b)) 15 to 85 parts by weight (c) an α-olefin and an α,β-unsaturated carboxylic acid unit containing 1 mol% or more and 30 mol% or less and in which at least 20 mol% of the carboxyl groups are present as mono- to trivalent metal salts; - a metal salt of a copolymer of an unsaturated carboxylic acid and a third vinyl monomer (component (c)), and (d) a block copolyether ester elastomer (component (d)), The total amount of component c) and component (d) is
20 parts per 100 parts by weight of the total amount of ingredients (a) and (b)
-50 parts by weight, and the ratio of the amount of component (d) to component (c) ((d)/(c)) is 10 or less. 2. The resin composition according to claim 1, wherein component (a) is polyethylene terephthalate. 3. The resin composition according to claim 1, wherein component (c) is a 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 mono- to trivalent metal constituting component (c) is sodium. 5. The block copolyether ester elastomer (component (d)) is a block copolymer of polyester and poly(tetramethylene oxide) glycol, of which 60 mol% or more is poly(1,4-butylene terephthalate). The resin composition according to claim 1. 6. The resin composition according to claim 1, wherein component (b) is poly(1,4-butylene terephthalate).