JPH06107930A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition useful as parts of automobiles having excellent transparency, heat resistance and mechanical characteristics, comprising a specific polyester resin, a specific phosphoric acid-based compound, etc., in a specified ratio. CONSTITUTION:The objective composition comprises (A) a polyester resin composed of a glycol unit consisting essentially of 1,4-butanediol unit and a dicarboxylic acid unit consisting essentially of terephthalic acid, having 30J/g crystallizing calorie in a drop in temperature at 10 deg.C/minute rate from a molten state at 290 deg.C, (B) a polyester resin composed of a glycol unit consisting essentially of 1,4-cyclohexanedimethanol unit and ethylene glycol unit, containing 20-65mol% 1,4-cyclohexanedimethanol unit and a dicarboxylic acid unit consisting essentially of terephthalic acid unit and (C) a phosphoric acid-based compound of the formula (R<1> and R<4> are H, alkyl, etc.; R<2> and R<5> are tertiary alkyl; R<4> and R<6> are H or alkyl; M is alkali metal) in the weight ratio of the component A/B of 60/40-99/1 and the components (A+B)/C of 1/0.00001-1/0.001.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester resin composition comprising a specific combination of two polyester resins and a compounding agent. Since the molded product having excellent mechanical properties, heat resistance and transparency can be produced from the polyester resin composition of the present invention, the polyester resin composition of the present invention is useful as a material for various molded products.

[0002]

2. Description of the Related Art Polytetramethylene terephthalate (P
BT) is a resin material for automobile parts, electric parts, electronic parts, etc. as an engineering plastic because it gives polyester molded products with high crystallinity that are excellent in mechanical properties, heat resistance and other properties due to their high crystallinity. Widely used as. However, since PBT easily generates coarse crystal nuclei, it has a strong tendency to be whitened and is unsuitable as a resin material for molded articles requiring transparency. Therefore, an attempt to obtain a PBT molded article with improved transparency has been studied, and as one of the attempts, a sheet using a resin material of PBT obtained by copolymerizing a comonomer such as paraxylidene glycol has been proposed. (JP-A-3-223339).

[0003]

In order to impart heat resistance, it is necessary for the sheet using the above-mentioned copolymerized PBT as a resin material to have a higher degree of crystallinity by heat treatment after molding. As described above, the molded article using the above-mentioned copolymerized PBT as a resin material has improved transparency due to copolymerization of the comonomer, but concomitantly with it, the heat resistance due to amorphization is reduced, which is an excellent property inherent to PBT. Since the various characteristics are lost,
It has a drawback that a complicated post-treatment such as heat treatment is required. However, the object of the present invention is to have excellent properties derived from high crystallinity, such as mechanical properties and heat resistance, even when a complicated post-treatment step is not performed, and is also excellent in transparency. It is intended to provide a polyester-based resin capable of producing a molded product.

[0004]

Means for Solving the Problems As a result of studies to achieve the above object, the present inventors have found that a specific PBT-based polyester resin and a specific amorphous polyethylene terephthalate-based resin having a high compatibility therewith. A polyester resin composition consisting of a copolyester resin and a specific compounding agent not only exhibits excellent properties in terms of mechanical properties, heat resistance, etc., but also does not whiten even when exposed to high temperatures. We found that it gives molded products that do not lose transparency,
As a result of further study, the present invention has been completed.

That is, the present invention comprises a glycol unit mainly containing 1,4-butanediol unit and a dicarboxylic acid unit mainly containing terephthalic acid unit, and 290
A polyester resin (a) having a heat of crystallization of 30 J / g or more when cooled at a rate of 10 ° C./min from a molten state of 1, and mainly composed of a 1,4-cyclohexanedimethanol unit and an ethylene glycol unit, and The 1,4-
A polyester resin (b) comprising a glycol unit containing 20 to 65 mol% of cyclohexanedimethanol unit and a dicarboxylic acid unit mainly containing a terephthalic acid unit, and the following general formula (I):

[0006]

[Chemical 2]

(Wherein R ¹ and R ⁴ each represent a hydrogen atom or an alkyl group or together represent a methylene group, R ² and R ⁵ each represent a third alkyl group, and R ³ and R ⁶ represents a hydrogen atom or an alkyl group, and M represents an alkali metal atom.)

The phosphoric acid compound (c) represented by the formula (3) is used, and the weight ratio of the polyester resin (a) to the polyester resin (b) is (a) / (b): 60 / 40-9.
9/1 and the weight ratio of the polyester resins (a) and (b) to the phosphoric acid compound (c) is [(a) + (b)] / (c), which is 1 / 0.00001. ~ 1
It is a polyester resin composition characterized by being /0.001.

In the present invention, the polyester resin (a) and the polyester resin (b) are used as the polyester resin.
And two types of polyester resin are used.

The polyester resin (a) is used for the molded product obtained from the viewpoint of exhibiting excellent mechanical properties derived from high crystallinity and heat resistance in combination with excellent transparency.
It is necessary that the heat of crystallization when the temperature is lowered at a rate of 10 ° C./minute from the molten state of 90 ° C. is 30 J / g or more.
When the amount of heat of crystallization is less than 30 J / g, the resulting molded article generally has low crystallinity and thus has insufficient heat resistance, and whitening easily occurs when exposed to high temperature conditions. Not preferable. From the point that the polyester resin (a) has a heat of crystallization of 30 J / g or more, 1,4-
It is preferable that the butanediol unit and the terephthalic acid unit are contained in a proportion of 80 mol% or more, particularly 85 mol% or more of the glycol unit and the dicarboxylic acid unit, respectively. On the other hand, the upper limit of the heat of crystallization of the polyester resin (a) is not particularly limited.
/ G or less is preferable. From the viewpoint that the resulting molded article exhibits particularly excellent transparency, the heat of crystallization is 45
It is desirable not to exceed J / g. In this viewpoint,
Glycol units other than 1,4-butanediol units and / or dicarboxylic acid units other than terephthalic acid units preferably account for 1 mol% or more of all structural units consisting of all glycol units and all dicarboxylic acid units.
Examples of the dicarboxylic acid unit other than the terephthalic acid unit which the polyester resin (a) may have in the molecule include isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid and paraphenylenedicarboxylic acid. Examples thereof include units of acids and aromatic dicarboxylic acids such as sodium sulfoisophthalate; units of aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, suberic acid, dodecanedioic acid, and cyclohexanedicarboxylic acid. Further, as the glycol unit other than the above 1,4-butanediol unit, diethylene glycol,
Triethylene glycol, tetraethylene glycol,
Examples include cyclohexanedimethanol, ethylene glycol, propylene glycol, pentanediol, hexanediol, neopentyl glycol, ethylene oxide adduct of bisphenol A, ethylene oxide adduct of bisphenol S, and glycol units such as spiroglycol. From the viewpoint that all of the mechanical properties, heat resistance and transparency of the obtained molded product are particularly good, the polyester resin (a) contains 99 to 81 of all structural units consisting of all glycol units and all dicarboxylic acid units.
Mol% occupies 1,4-butanediol units and terephthalic acid units, and the remaining 1 to 19 mol% is isophthalic acid units, structural units derived from ethylene oxide adducts of bisphenol A and ethylene oxide adducts of bisphenol S. It is preferable that at least one structural unit selected from the group consisting of derived structural units is occupied.

In the polyester resin (b) of the present invention, it is important that 20 to 65 mol% of the glycol units are 1,4-cyclohexanedimethanol units.
When the 1,4-cyclohexanedimethanol unit is less than 20 mol% or more than 65 mol% based on the glycol unit, the obtained molded article generally has low crystallinity and thus has insufficient heat resistance. In addition, it is not preferable because whitening is likely to occur when it is subjected to heat treatment.

If the amount of the polyester resin (b) is small, dicarboxylic acid units other than terephthalic acid units and / or
Alternatively, it may have a glycol unit other than the ethylene glycol unit and the 1,4-cyclohexanedimethanol unit in its molecule. Examples of the dicarboxylic acid unit other than the terephthalic acid unit include isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, diphenyl-4,4′-
Aromatic dicarboxylic acid units such as dicarboxylic acid, paraphenylenedicarboxylic acid, and sodium sulfoisophthalate;
Examples thereof include units of aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, suberic acid, dodecanedioic acid, and cyclohexanedicarboxylic acid. Examples of the glycol unit other than the ethylene glycol unit and the 1,4-cyclohexanedimethanol unit include diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, and ethylene of bisphenol A. Oxide adduct,
Examples thereof include ethylene oxide adducts of bisphenol S and glycol units such as spiroglycol.

The polyester resin (a) and the polyester resin (b) are trifunctional or higher polyfunctional compounds such as trimellitic acid and pentaerythritol, as long as the amounts are small enough not to substantially impair thermoplasticity. If necessary, it may contain a trivalent or higher valent structural unit.

The intrinsic viscosities of the polyester resin (a) and the polyester resin (b) are not necessarily limited, but from the viewpoint of the mechanical properties of the obtained molded product, etc.
3 in an equal weight mixed solvent of phenol / tetrachloroethane
The intrinsic viscosity measured at 0 ° C. is within the range of 0.65 to 1.50 dl / g for the polyester resin (a) and within the range of 0.45 to 1.00 dl / g for the polyester resin (b). It is preferable.

Both the polyester resin (a) and the polyester resin (b) described above are used in the methods generally used for producing ordinary thermoplastic polyester resins such as polytetramethylene terephthalate and polyethylene terephthalate. It can be manufactured in a similar manner. For example, a dicarboxylic acid raw material consisting of a dicarboxylic acid mainly composed of terephthalic acid or a lower alkyl ester thereof,
A glycol raw material mainly composed of 1,4-butanediol or a glycol raw material mainly composed of ethylene glycol and 1,4-cyclohexanedimethanol is subjected to an esterification reaction or a transesterification reaction to obtain a low polymer,
The low polymer is melt-polycondensed to produce polyester, and then the polyester is made into a die in any shape such as a die shape or a column shape. Further, if desired, the tip is solid-phase polymerized to obtain a chip-shaped polyester resin. Can be manufactured.

The polyester resin (a) in the polyester resin composition of the present invention is 40% of the polyester resin (b).
It is 60 parts by weight or more with respect to parts by weight, and 99 parts by weight or less with respect to 1 part by weight of the polyester resin (b). When the proportion of the polyester resin (a) is less than 60 parts by weight relative to 40 parts by weight of the polyester resin (b), the resulting molded article is likely to be whitened under high temperature conditions, which is not preferable. Polyester resin (I)
Is 9 parts by weight with respect to 1 part by weight of the polyester resin (b).
When it exceeds 9 parts by weight, the transparency of the obtained molded product becomes poor. In the present invention, the phosphoric acid compound (c) represented by the general formula (I) is blended. Examples of the alkyl group that may be represented by R ¹ , R ³ , R ⁴ and R ^{6 in the} general formula (I) include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl and the like. Lower alkyl groups of are preferred.
The third alkyl group represented by R ² and R ⁵ is tert.
-Butyl group is preferred. The alkali metal atom represented by M is preferably a sodium atom. As the phosphoric acid compound (c), 2,2-methylenebis (4,6-di-tert-butylphenyl) phosphate represented by the following chemical formula 3 is obtained from the viewpoint that the resulting molded article has particularly good transparency. Sodium, bis (4-ter phosphate) represented by the following chemical formula 4
t-butylphenyl) sodium and the like are preferable.

[0017]

[Chemical 3]

[0018]

[Chemical 4]

In the polyester resin composition of the present invention, the phosphoric acid compound (c) is the polyester resin (a).
0.0 with respect to the sum of the weight of the polyester resin (b)
It is blended in a ratio of 0001 to 0.001 times the weight. When the mixing ratio of the phosphoric acid compound (c) is less than 0.00001 times the sum of the weights of the polyester resin (a) and the polyester resin (b), it is based on the phosphoric acid compound (c). The effect of improving the transparency of the molded product is not sufficiently exhibited. On the other hand, the compounding ratio of the phosphoric acid compound (c) is 0.00
Even if it exceeds 1 time, the transparency of the obtained molded article will be deteriorated, which is not preferable. In the polyester resin composition of the present invention, the form of blending the polyester resin (a), the polyester resin (b) and the phosphoric acid compound (c) is not particularly limited, and the polyester resin (a) chips, polyester resin A dry blend of chips of (b) and powder of phosphoric acid compound (c), melt obtained by blending phosphoric acid compound (c) during melt blending of polyester resin (a) and polyester resin (b) Any of blends and the like can be mentioned.

The polyester resin composition of the present invention can be molded into articles of various shapes by subjecting it to melt molding such as injection molding and extrusion molding (T-die method, inflation method, etc.) in a conventional manner. Furthermore, it is possible to subject the pipe-shaped material obtained by injection molding or extrusion molding to blow molding, and subject the sheet obtained by extrusion molding to thermoforming. In the melt molding of the polyester resin composition of the present invention, for example, a dry blend of chips of the polyester resin (a), chips of the polyester resin (b) and powder of the phosphoric acid compound (c) is melt-kneaded, and then, Method of melt molding, method of mixing with a phosphoric acid compound (c) when subjecting a chip made of a melt blend of polyester resin (a) and polyester resin (b) to melt molding, polyester resin (a), polyester Any method such as a method of subjecting chips of a melt blend of the resin (b) and the phosphoric acid compound (c) to melt molding can be adopted. For example, in injection molding, the melting temperature is 220 to 280 ° C and the mold temperature is 10 to 60 ° C.
When a molded product having a wall thickness of 4 mm or less is manufactured under the molding conditions of 1, the effects of the present invention in terms of mechanical properties, heat resistance and transparency of the resulting molded product are particularly effectively exhibited.

Molded articles obtained from the polyester resin composition of the present invention include exterior materials, interior materials, electric products, electronic parts,
It can be used as an optical component, daily sundries, food packaging, etc.

[0022]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

In the following Examples and Comparative Examples, the intrinsic viscosity of the obtained polyester resin was measured at 30 ° C. in an equal weight mixed solvent of phenol / tetrachloroethane. Further, of the obtained polyester resins, polytetramethylene terephthalate type polyester is melted at 290 ° C. and then subjected to thermal analysis by the DSC method (differential scanning calorimetry) while lowering the temperature at a rate of 10 ° C./min. Thus, the heat of crystallization (ΔHcc) was measured. A 100 mm long, 100 mm wide, 1 mm thick flat plate molded from the obtained polyester resin by an injection molding method and a flat plate after heat treatment at 150 ° C. for 3 hours were used. The transparency of the molded article was evaluated by the haze value according to ASTM D1003. Furthermore, a length of 110 mm, a width of 12.7 mm, which was molded from the obtained polyester resin by an injection molding method,
Using a 3.0 mm thick rod, the mechanical properties of the molded article were determined by tensile strength and elongation according to ASTM D638, flexural strength and modulus according to ASTM D790 and notched Izod impact strength according to ASTM D256. Also, the heat resistance of the molded product is ASTM
Each was evaluated by the heat distortion temperature according to D648.

Example 1 Ethylene glycol 69.2
Mol% and 1,4-cyclohexanedimethanol 3
From the glycol raw material consisting of 0.8 mol% and terephthalic acid, the molar ratio of glycol raw material: terephthalic acid is 1.
The slurry was adjusted to 2: 1 to form a slurry, and the slurry was heated under pressure (absolute pressure 2.5 kg / cm ² ) to 250
A low polymer was produced by carrying out an esterification reaction at a temperature of ° C until the esterification rate reached 95%. Next, 35 as a catalyst
A low polymer was polycondensed at a temperature of 280 ° C. under a reduced pressure of 1 Torr absolute pressure by adding 0 ppm of antimony trioxide to prepare a polymer having an intrinsic viscosity of 0.75 dl / g. This polymer was extruded from a nozzle in a strand shape and cut into a cylindrical chip having a length of 3.2 mm and a diameter of 2.8 mm. When the obtained polyester resin chip was analyzed by ¹ H-NMR, it was confirmed that the polyester was a polyethylene terephthalate-based copolyester containing 33 mol% of 1,4-cyclohexanedimethanol units in all glycol units. It was

250 ppm of tetraisopropyl titanate was prepared by adjusting 1,4-butanediol and a dicarboxylic acid raw material consisting of 90 mol% of dimethyl terephthalate and 10 mol% of dimethyl isophthalate to a molar ratio of 1.3: 1. As a catalyst under atmospheric pressure from 145 ° C to 230
The temperature was gradually raised to 0 ° C. to carry out a transesterification reaction to produce a low polymer. Next, under reduced pressure of 1 Torr absolute pressure, 240
Polycondensation of low polymer at a temperature of ℃, intrinsic viscosity 0.85dl
/ G of polymer was prepared. This polymer was extruded from a nozzle in a strand shape and cut into a cylindrical chip having a length of 3.2 mm and a diameter of 2.8 mm. When the obtained polyester resin chip was analyzed by ¹ H-NMR, it was confirmed that the polyester was a polytetramethylene terephthalate-based polyester in which isophthalic acid units were contained in an amount of 10 mol% in all dicarboxylic acid units.

25 parts by weight of the obtained polyethylene terephthalate type copolyester chips, 75 parts by weight of polytetramethylene terephthalate type polyester chips and 2,2-methylenebis (4,6-di-tert-butylphenyl) sodium phosphate 0.01% By blending 1 part by weight, a single-screw extruder (UT-4 manufactured by Plastic Engineering Laboratory)
Melt-kneading / extrusion at a temperature of 210 to 230 ° C. to produce a cylindrical kneading chip having a length of 3.2 mm and a diameter of 2.8 mm. 260 this kneading tip
By melting at ℃ and injection molding at a mold temperature of 40 ℃, 100 mm long, 100 mm wide, 1 mm thick flat plate and 110 mm long, 12.7 mm wide, 3.0 thick
mm rods were manufactured respectively. The transparency and mechanical properties were evaluated using these molded articles. The obtained results are shown in Tables 2 and 3.

<Example 2> A kneading chip was produced in the same manner as in Example 1 except that the mixing ratio of the polyethylene terephthalate copolyester and the polytetramethylene terephthalate polyester was changed as shown in Table 1, and injection was performed. A flat plate and a rod were manufactured by molding. Table 2 shows the evaluation results of the obtained molded products.

<Example 3> The types of phosphoric acid compounds are shown in Table 1.
A kneaded chip was produced and injection-molded to produce a flat plate-shaped product and a rod-shaped product, respectively, in the same manner as in Example 2 except that the changes were made as shown in FIG. Table 2 shows the evaluation results of the obtained molded products.

<Examples 4 and 5> As raw materials for producing a polytetramethylene terephthalate type polyester, 96.1 mol% of 1,4-butanediol and bis [4- (2-hydroxyethoxy) phenyl] sulfone 3 were used. A mixture of glycol and dimethyl terephthalate in a molar ratio of 1.3: 1 (Example 4) or 93.8 mol% of 1,4-butanediol and 2,2-
Example 1 except that a mixture of glycol consisting of 6.2 mol% bis [4- (2-hydroxyethoxy) phenyl] propane and dimethyl terephthalate in a molar ratio of 1.3: 1 (Example 5) was used. Similarly, polyethylene terephthalate copolyester and polytetramethylene terephthalate polyester as shown in Table 1 were produced,
Kneading chips were produced using these polyester resins and 2,2-methylenebis (4,6-di-tert-butylphenyl) sodium phosphate, and flat plates and rods were produced by injection molding. . Table 2 shows the evaluation results of the obtained molded products.

Comparative Example 1 1,4-butanediol and dimethyl terephthalate were adjusted so that the molar ratio was 1.3: 1, and 250 ppm of tetraisopropyl titanate was used as a catalyst at 145 ° C. under normal pressure. The temperature was gradually raised to 230 ° C. to carry out a transesterification reaction to produce a low polymer. Next, the low polymer was polycondensed at a temperature of 240 ° C. under a reduced pressure of 1 torr absolute pressure to prepare a polymer having an intrinsic viscosity of 0.85 dl / g. This polymer is extruded from a nozzle in a strand shape and cut into a length of 3.2 mm and a diameter of 2.8 m.
m columnar polyester resin chips were manufactured. The obtained polyester resin was polytetramethylene terephthalate. The obtained polytetramethylene terephthalate was injection-molded as it was under the same molding conditions as in Example 1 to produce a flat plate and a rod. Table 2 shows the evaluation results of the obtained molded products.

Comparative Example 2 Only 25 parts by weight of polyethylene terephthalate type copolyester chips obtained in the same manner as in Example 1 and 75 parts by weight of polytetramethylene terephthalate chips obtained in the same manner as in Comparative Example 1 are used. Except for the above, in the same manner as in Example 1, a kneaded chip containing no phosphoric acid compound was produced. By using this kneading chip, injection molding was carried out under the same molding conditions as in Example 1 to produce a flat plate-shaped product and a rod-shaped product. Table 2 shows the evaluation results of the obtained molded products.

<Comparative Example 3> As a raw material for producing a polytetramethylene terephthalate polyester,
The same procedure as in Example 1 was repeated except that a mixture of 1,4-butanediol and 80 mol% of dimethyl terephthalate and 20 mol% of dimethyl isophthalate was used as a dicarboxylic acid raw material in a molar ratio of 1.3: 1. 1. Polyethylene terephthalate type copolyester and polytetramethylene terephthalate type polyester as shown in 1 are produced, and these polyester resins and 2,2-methylenebis (4,6-di-tert-butylphenyl) sodium phosphate are used. A kneaded chip was produced and injection-molded to produce a flat plate and a rod. Table 2 shows the evaluation results of the obtained molded products.

<Comparative Examples 4 and 5> 1 was carried out in the same manner as in Example 1 except that the ratio of the glycol raw material ethylene glycol and 1,4-cyclohexanedimethanol used in the production of the polyethylene terephthalate copolyester was changed. Cylindrical chips of polyethylene terephthalate copolyester containing 15 mol% or 70 mol% of 4,4-cyclohexanedimethanol units in all glycol units were produced. Kneading chips were produced in the same manner as in Example 1 except that the obtained polyethylene terephthalate-based copolyester was used, and injection molding was carried out to produce flat plates and rods. Table 2 shows the evaluation results of the obtained molded products.

<Comparative Example 6> A kneading chip was produced in the same manner as in Example 1 except that the mixing ratio of the polyethylene terephthalate type copolyester and the polytetramethylene terephthalate type polyester was changed as shown in Table 1, and injection was performed. A flat plate and a rod were manufactured by molding. Table 2 shows the evaluation results of the obtained molded products.

Comparative Example 7 The procedure of Example 1 was repeated except that the amount of the phosphoric acid compound used was changed as shown in Table 1.
A kneaded chip was produced and injection-molded to produce a flat plate and a rod. Table 2 shows the evaluation results of the obtained molded products.

[0036]

[Table 1]

In Table 1 above, "PBT-based resin" represents polytetramethylene terephthalate-based polyester resin, "PET-based resin" represents polyethylene terephthalate-based copolyester resin, and "corresponding structural unit content of PBT-based resin". Represents the content of structural units derived from the comonomer used, based on the total glycol units or the total dicarboxylic acid units, and is represented by "1,4-
"CHDM corresponding structural unit content" represents the content of 1,4-cyclohexanedimethanol units on the basis of all glycol units, "BPSEO" represents bis [4- (2-hydroxyethoxy) phenyl] sulfone, and "BPAEO". "
Represents 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, "A" represents 2,2-methylenebis (4,6-di-tert-butylphenyl) sodium phosphate, and "B". "Represents sodium bis (4-tert-butylphenyl) phosphate.

[0038]

[Table 2]

[0039]

[Table 3]

From the above results, the molded articles obtained by using the polyester resin compositions of the present invention of Examples 1 to 5 are excellent in transparency and have good transparency even when exposed to high temperature conditions for a long time. It turns out to hold. Further, it can be seen that the molded product obtained by using the polyester resin composition of the present invention has excellent mechanical properties and heat resistance. On the contrary,
When the compounding amount of the phosphoric acid compound is lacking (Comparative Examples 1 and 2), when the heat of crystallization of the polytetramethylene terephthalate polyester is less than 30 J / g (Comparative Example 3), 1,4-in the polyethylene terephthalate copolyester.
Cyclohexanedimethanol unit content is 20 mol%
When it is less than or exceeds 65 mol% (Comparative Examples 4 and 5), when the blending ratio of the two polyester resins is out of the range specified in the present invention (Comparative Example 6), and the phosphoric acid compound is blended. It can be seen that when the amount is too large (Comparative Example 7), the resulting molded article has insufficient transparency or is significantly devitrified when exposed to high temperature conditions.

[0041]

The molded article obtained from the polyester resin composition of the present invention has excellent transparency, retains good transparency even when exposed to high temperature conditions for a long time, and has good mechanical properties and heat resistance. Is also excellent.

Claims (1)

[Claims] 1. When it is composed of a glycol unit mainly composed of 1,4-butanediol unit and a dicarboxylic acid unit mainly composed of terephthalic acid unit and is cooled at a rate of 10 ° C./minute from a molten state at 290 ° C. Heat of crystallization of 30J /
Polyester resin (a) of g or more, 1,4-cyclohexanedimethanol unit and ethylene glycol unit as a main component, and glycol unit and terephthalic acid containing 20 to 65 mol% of the 1,4-cyclohexanedimethanol unit. A polyester resin (b) composed of a dicarboxylic acid unit having units as a main unit and the following general formula (I): (In the formula, R ¹ and R ⁴ each represent a hydrogen atom or an alkyl group, or together represent a methylene group; R ² and R ⁵ each represent a third alkyl group;
³ and R ⁶ each represent a hydrogen atom or an alkyl group, and M represents an alkali metal atom), and the polyester resin (a) and the polyester resin (b) Weight ratio is (a) /
(B) is 60/40 to 99/1, and the weight ratio of the polyester resins (a) and (b) to the phosphoric acid compound (c) is [(a) + (b)] / ( 1 / in c)
The polyester resin composition is 0.00001 to 1 / 0.001.