JPH0214238A - Polyester composition and drawn polyester sheet and hollow polyester vessel made of the same composition - Google Patents

Abstract

PURPOSE:To provide the subject composition containing polyethylene terephthalate and a copolymerized polyester composed of dicarboxylic acid components having a specific composition, having high transparency and excellent strength and gas-barrier property and suitable for a drawn sheet and a hollow vessel. CONSTITUTION:The objective composition is composed of (A) 20-95wt.% of polyethylene terephthalate and (B) 80-5wt.% of a copolymerized polyester produced by the copolymerization of a diol component with a dicarboxylic acid component containing (B1) isophthalic acid (or its ester-forming derivative) and (B2) a dicarboxylic acid of formula (R is halogen, alkoxy, phenyl or alkyl, preferably methoxy, methyl or ethyl; n is 0-4) or its ester-forming derivative at a molar ratio (B1:B2) of (10-95):(90-5), preferably (30-90):(70-10). The sum of B1 and B2 is >=50mol% of the whole acid components. The drawn sheet and the hollow vessel can be produced by forming the above composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyester composition having high transparency and excellent strength and gas barrier properties, and a packaging material molded using the same.

[Conventional technology]

Polyethylene terephthalate has excellent mechanical strength, chemical stability, transparency, hygiene, etc., and is also lightweight and inexpensive, so it is widely used as a packaging material for various sorting and containers. , carbonated drinks, fruit juice drinks,
Demand is rapidly increasing for containers for liquid seasonings, edible oil, alcohol, and wine.

However, the gas barrier properties of polyethylene terephthalate are superior to those of other resins such as polyolefins.
However, there are some fields that require an even higher level, and the level cannot be said to be sufficient. For example, in applications such as carbonated drinks, beer, and wine, particularly strict oxygen gas barrier properties and carbon dioxide gas barrier properties are required from the viewpoint of content preservation, and biaxially oriented polyethylene terephthalate is commonly used. It cannot be said that a hollow container made of the above necessarily has sufficient gas barrier properties.

For this reason, there have been proposals to further improve the gas barrier properties of containers made of polyethylene terephthalate, and gas barrier containers in which polyethylene isophthalate or its copolyester is made friendlier to polyethylene terephthalate (JP-A-59-4965G1). 1986-ta 3
Otsu 55).

However, the level of gas barrier properties of these polyesters is not sufficient, and in order to improve the gas barrier properties to the full range of polyethylene terephthalate, a considerable proportion of gold must be blended, and in this case, polyethylene terephthalate The inherent strength and heat resistance of the container will be sacrificed.

In addition, polyvinylidene chloride, saponified ethylene-vinyl acetate copolymer, and polyamide are generally known as materials with high gas barrier properties.
The material has poor compatibility with polyethylene terephthalate and has a large difference in refractive index, so the transparency of the blend is significantly impaired.

[Purpose of the invention]

The entire object of the present invention is to provide a polyester composition that has excellent physical properties such as mechanical strength and gas barrier properties and is highly transparent, and sheets and containers made of the same.

[Structure of the invention]

The present invention comprises: (1) 20 to 95% by weight of polyethylene terephthalate; (2) (a) isophthalic acid or its ester-forming derivative; (b) dicarboxylic acid represented by the following - allowance (1) or its ester-forming derivative; This is a polyester composition consisting of a dicarboxylic acid component containing all diol components and a copolymerized polyester obtained by copolymerizing gOS-5% by weight, and the ratio of (a) and (b) of the copolymerized polyester is ( a) : (b)
=-/-θ~da, s knee r-ρ→-5) ((2 mol% ratio), and the sum of (a) units and (b) units is 50% of the total acid component of the copolymerized polyester. The present invention relates to a polyester composition characterized in that the mole is 9 or more.

Further, a sheet with excellent gas barrier properties obtained by stretching a sheet obtained by injection molding or extrusion molding of the polyester composition, and a sheet obtained by stretch-blow molding the polyester composition gas barrier properties, transparency,
This relates to a hollow container with excellent mechanical strength.

(In the formula, R is a halogen, an alkoxy group, a phenyl group,
or represents a substituent selected from alkyl groups. n is θ~
is an integer of q. ) Among R in the above-mentioned - machining allowance (1), as the alkoxy group, those having carbon number/-- are preferable, and methoxy group is particularly preferable. The alkyl group preferably has a carbon number of 1 to 3, and more preferably a methyl group or an ethyl group.

- The dicarboxylic acid represented by removal allowance (1) is specifically /, 2-phenylenedioxydiacetic acid, /, J-phenylenedioxydiacetic acid, /, 'I-phenylenedioxydiacetic acid, λ-Methyl-7,3-phenylenedioxydiacetic acid, 5-methyl-/,3-phenylenedioxydiacetic acid, 6
-Methyl-/,,3-phenylenedioxydiacetic acid,! −
Ethyl/, 3-phenylenedioxydiacetic acid, 6-nityl/, 3-phenylenedioxydiacetic acid, 5-methoxy-1,3-phenylenedioxydiacetic acid, 6-medoxy/, 3-phenylenedioxy Diacetic acid, dark roll/,
2-phenylenedioxycyacetic acid, p-chloro-/, 3-
Examples include phenylene dioxy7 diacetic acid. Among these, derivatives of /,3-phenylenedioxydiacetic acid are preferred, and /,3-phenylenedioxydiacetic acid is more preferred.

The dicarboxylic acid represented by the general formula (1) may be used as is in combination with inphthalic acid, or may be used as an acid anhydride, an acid halide,
It may also be used as ester-forming derivatives such as monoesters and diesters.

Alternatively, it may be added after being quantified by reacting with glycols.

Inphthalic acid may also be used in the form of ester-forming derivatives that react with diol components, such as ester derivatives such as dimethyl inphthalate and diethyl inphthalate, and isophthalic acid halogenated compounds such as ink 1'yl acid 0ride. .

In the copolymerized polyester used in the polyester composition of the present invention, the molar percentage ratio of (a) inphthalic acid units to) dicarboxylic acid units represented by the above-mentioned removal allowance (1) is l
O~qs: qo~5, preferably 30-90 near 0-1
It is in the range of 0.

- If the total amount of dicarboxylic acid units represented by machining allowance (1) exceeds this range, the glass transition point (Tg) of the resulting copolyester will drop too much, so Drying becomes difficult, and the heat resistance of a molded product obtained by blending the obtained copolyester with polyethylene terephthalate decreases. on the other hand,
- If the amount of dicarboxylic acid units represented by machining allowance (1) is less than this range, the level of gas barrier properties will be insufficient. -sexual superiority
7t polyester Not suitable for use as packaging material.

In the copolymerized polyester used in the polyester composition of the present invention, the sum of the inphthalic acid units and the dicarboxylic acid units represented by general formula (1) accounts for at least SO mol% or more of the repeating units of the total acid component. It's nice.

If the sum of both is less than 5θ mol %, the copolymerized polyester will not have sufficient gas barrier properties and cannot be used as the packaging material of the present invention. Further, other dicarboxylic acids and oxyacids may be used as long as the molar ratio of inphthalic acid and dicarboxylic acid represented by general formula (1) satisfies the above-mentioned molar ratio.

These dicarboxylic acids include terephthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, +4'-diphenoxyethanedicarboxylic acid, y,ll'-diphenylsulfonedicarboxylic acid, and structural isomers thereof, Examples of aliphatic dicarboxylic acids such as malonic acid, succinic acid, and adipic acid, or oxyacids include hydroxybenzoic acid derivatives and glycolic acid.

Diol components used in the copolymerized polyester used in the polyester composition of the present invention include ethylene glycol, l,2-propanediol, /, 3-7'ropanediol, /, 4'-butanediol, pentamethylene glycol, Examples include hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, diethylene glycol, and aromatic dihydroxy compound derivatives such as bisphenol A1 and bisphenol S. Among these, ethylene glycol is most preferred for boat fishing.

In addition, the copolymerized polyester used in the present invention may include trimethylolpropane, trimethylolpropane,
pentaerythritol, chrycerin, trimellitic acid,
Polyfunctional compounds such as trimene heptanoic acid and pyromellitic acid,
All monofunctional compounds such as 0-benzoylbenzoic acid may be present. Such polyfunctional compounds and monofunctional compounds are used in an amount of 20 mol% or less of the diol component.

The copolymerized polyester used in the present invention has an intrinsic viscosity [phenol/tetrachloroethane (weight ratio 1/
The value measured at 30°C using the mixed solvent of 1) is o,
lI-Co, O1 is preferably in the range from O, SO to 8. If the intrinsic viscosity is less than 0 or ti, the strength of the obtained polyester will be low, and it will be difficult to remove it from the reaction vessel after the polymerization reaction and cut it into chips, or blend it with polyethylene terephthalate to make films, sheets, bottles, barrels, etc. The physical properties required for practical purposes cannot be obtained when molded into containers such as cans. If the intrinsic viscosity exceeds Q or Q, the melt viscosity becomes too high, causing problems such as difficulty in molding by injection, extrusion, blowing, etc.

The copolyester (1) can be produced by a conventionally known polymerization method for polyethylene terephthalate. For example, a direct esterification reaction is performed under pressure with isophthalic acid and a dicarboxylic acid represented by the general formula (1), specifically l,3-phenylenedioxydiacetic acid, and ethylene glycol kumquat under pressure. There is a method in which the temperature is raised and the pressure is gradually reduced to cause a polycondensation reaction.

Alternatively, an ester derivative of inphthalic acid, such as isophthalic acid dimethyl ester, and an ester derivative of dicarboxylic acid represented by (1), such as /, 3-phenylenedioxydiacetic acid dimethyl ester, and ethylene glycol may be used. It can be produced by carrying out a transesterification reaction, and then polycondensing the entire reaction product obtained. At that time, it is preferable to use an esterification catalyst, a transesterification catalyst, a polycondensation catalyst, a stabilizer, etc.

As the transesterification catalyst, seven or more known compounds such as calcium, manganese, zinc, sodium, and lithium compounds can be used, but manganese compounds are particularly preferred from the viewpoint of transparency. As the polymerization catalyst, one or more of known antimony, germanium, titanium, and hycobalt compounds can be used, but antimony, germanium, and titanium compounds are preferably used.

In addition, in the present invention, conventionally known additives such as antioxidants, ultraviolet absorbers, fluorescent whitening agents, mold release agents, antistatic agents, dispersants, and colorants such as dyes and pigments may be added as necessary. It may be added at any stage during the production of polyester, or may be added as a masterbatch formulation before molding.

The thus obtained copolyester (1) used in the polyester composition of the present invention is melt-molded with polyethylene terephthalate (2) to form a molded product. Specifically, it is possible to blend it with polyethylene terephthalate and melt-knead it in an extruder to obtain a mixed chip, which can then be used for molding, or to tri-blend all the components of the mold and mold it directly. It is also possible to provide Here, the ratio of the blend of polyethylene terephthalate and the copolymerized polyester of the present invention is such that the copolymer
Preferably, it accounts for ro% by weight. If the proportion of the copolymer is less than 3% by weight, the effect of improving the gas barrier properties of polyethylene terephthalate will be insufficient, and if it exceeds go% by weight, the performance of the molded product will deteriorate in terms of mechanical strength and heat resistance. nru.

The polyester composition of the present invention can be molded into films, sheets, containers, and other packaging materials using a melt molding method commonly used in molding polyethylene terephthalate, and even in an unstretched state, it can be used as a gas barrier. −
It can be used as a material with high properties. 'Also, by stretching the polyester composition at least in the l-axis direction, it is possible to further improve gas barrier properties and mechanical strength.

The stretched sheet made of the polyester composition of the present invention is produced by forming the polyester composition of the present invention into a sheet by injection molding or extrusion molding, and then sequentially stretching the polyester composition of the present invention, which is normally used for stretching polyethylene terephthalate, along the nl axis. Shaping is performed using any stretching method among biaxial stretching and simultaneous biaxial stretching.

Moreover, it can also be molded into a cup shape or a tray shape by air pressure molding.

When producing a stretched sheet of the polyester composition of the present invention, the stretching temperature may be set between the glass transition temperature of the polyester of the present invention and a temperature 7θ° C. higher than the glass transition point. The stretching ratio is usually in the range of 1.1 to 70 times in the case of l-axis stretching, preferably in the range of 1.1 to 3 times, and in the case of biaxial stretching, in both the longitudinal and transverse directions. It may be carried out within a range of 1 to 3 times, preferably 1 to 3 times.

The stretched sheet made of the polyester composition of the present invention thus obtained has excellent transparency, gas carryability, and mechanical strength, and is useful as a packaging material in the form of a film, cup, tray, etc. be.

A polyester blow molded article made of the resin composition of the present invention is obtained by stretch blow molding a preform, and the equipment conventionally used for blow molding polyethylene terephthalate can be used. Specifically, for example, a -H preform is molded by extrusion blowing method, injection blowing method, injection molding, or extrusion molding, and then it is reheated as it is or after processing the spout and bottom part. , a blow molding method such as a hot parison method with biaxial stretching or a cold halinon method is applied.

The stretching temperature is 70 V and 120°C, preferably 10 to 110°C, and the stretching ratio is 5 to 3.5 in the machine direction.
It may be done in the range of 2 to 5 times in the circumferential direction.

``Also, in producing a polyester blow molded article, a preform is formed in which all the layers are made of the polyester composition of the present invention, the main layer is polyethylene terephthalate, and the layers are made of sulpolyalkylene terephthalate,
This n'ff: co-axial stretching blower M, which may be shaped into a multilayer blow molded container. At this time, there is no particular limitation on the layer structure, and a structure of about 3 to S layers is preferable. [Example] The present invention will be explained in more detail with reference to Examples below. limited to the following examples
Note that "parts" in the examples mean "parts by weight," and all of the various measurement methods used in the examples are shown below.

0 intrinsic viscosity Phenol-tetrachloroethane (to7s).

(weight ratio) at 30°C.

0 Oxygen permeability Extruded sheet samples and bottles with a wall thickness of approximately 200μ were created, and Rox-TRA was heated at 23°C and 10o%RH.
N to/so AJ oxygen permeability measuring device (USA Mo
cc-I
II/d-day-atm' or cc/bottle/da
Show friends at Y-ATM.

Production Example 1 3 g parts of dimethyl isophthalate, yg parts of naphthalene dicarboxylic acid dimethyl ester, 11 g of ethylene glycol
1 part and 0.0.7 part of mangantha acetate hydrate were added to the reactor, and the temperature was gradually raised from 160°C to 230°C, and the transesterification reaction was carried out until no effluent came out.

To this system, sq parts of J-phenylenedioxydiacetic acid, 0.02 parts of orthophosphoric acid, and 0.03 parts of germanium dioxide were added in this order, and the temperature was gradually raised from 230°C while the inside of the polymerization tank was brought to normal pressure. The pressure was gradually reduced from 0°C to 0. ! ;t
Intrinsic viscosity of 00 l in total polymerization time of 6 hours under vacuum of orr.
Made of highly transparent polyester.

, 2 μl Shioori, 2 dinotyl isophthalate f<! ;, 2 parts, /, 30 parts of 3-phenylene dicarboxylic acid/diacetic acid, naphthalene dicarboxylic acid dimethyl ester "k A j !B", 66 parts of ethylene glycol, but the entire polymerization was carried out in the same manner as in Production Example/ The limiting viscosity of the obtained polymer is θ, Otsu9
Met.

Production Example 3 Dimethyl isophthalate 5/part, /, 3-7 nitrogen/dioxydiacetic acid g? 1 part, 33 parts of ethylene glycol, and 0.03 part of titanium tetrabutoxide were added to the reaction vessel, and the temperature was gradually raised from 200°C to 230°C to carry out the entire transesterification reaction until no effluent came out.

Furthermore, the temperature was gradually raised from 1.230'C, and the pressure inside the polymerization tank was gradually reduced from normal pressure to 2bO'C/torr.
A highly transparent polyester gold having an intrinsic viscosity of 0.65 was obtained under vacuum for a total polymerization time of S and O hours.

Production Example: 2 parts of Kejinotyl Isophthalate fg, 32 parts of 3-enylene dioxygenate 7 diacetate, dimethyl naphthalene dicarboxylic acid ester? Polymerization was carried out in the same manner as in Production Example except that 3" parts of ethylene glycol and 70 parts of ethylene glycol were used. The intrinsic viscosity of the obtained polymer was 0.70.

Production Example 3 Complete polymerization was carried out in the same manner as Production Example 3 except that 1 part of dimethyl isophthalate, 33 parts of 3-phenylenedioxydiacetic acid, 73 parts of naphthalenedicarboxylic acid dimethyl ester, and 73 parts of ethylene glycol were used. Ta. The intrinsic viscosity of the obtained polymer was 0.4 g.

Comparative production example / For dimethyl inphthalate /! The polymerization of polyethylene isophthalate was carried out in the same manner as in Production Example, except that 2 parts of ethylene glycol and 9 parts of ethylene glycol were used.The intrinsic viscosity of the obtained polymer was 0,073.

The copolymerized polyesters obtained in Production Examples 1 to 5 and Comparative Production Example 1 were pressed into sheets of approximately 200μ, and the oxygen permeability was measured in total. The results are summarized in Table/.

Example/~2 The copolymerized polyester obtained in Production Example/-2 had an intrinsic viscosity of 0.7! was melt-kneaded with polyethylene terephthalate (RTrlI3c, manufactured by Nippon Unipet Co., Ltd.) at the ratio shown in Table 2 below, and the blend was pressed into a sheet of about -〇θμ. Table 2 shows the results of measuring the oxygen permeability of the obtained press sheets.

The copolymerized polyester obtained in Example 3 to Production Example 3 was blended into pellets with polyethylene terephthalate (Japan Unipet RTsti3C) at the ratio shown in Table 2 below, and injection molded (
Tone 0. g Oz injection molding) by AcnLX6
A flat plate of crrt was molded. Stretched to a thickness of approximately 100 mm by simultaneously stretching 3 times in both the longitudinal and lateral directions using a full length stretching machine.
A stretched sheet of μ was prepared, and the oxygen permeability was measured. The results are summarized in Table 1.

Comparative Example 1 - Regarding copolyethylene terephthalate (RT Tag 30 manufactured by Nippon Unipet), the oxygen permeability of the unstretched film was measured in the same manner as in Examples. Further, a stretched film was prepared in the same manner as in Examples 3 to 3, and the oxygen permeability of the film was totally measured. The results are shown in Table 2.

Comparative Examples 3 to q The polyethylene isophthalate obtained in Comparative Production Example 1 was blended with polyethylene terephthalate in the same manner as in Examples 3 to q, and the oxygen permeability of the unstretched film was measured. In addition, a stretched film of a blend with polyethylene terephthalate was prepared in the same manner as in Examples 3 to 1I,
This oxygen permeability was measured. The results are shown in Table 1.

Table Oxygen gas permeation amount of copolyester composition 1) Polyester composition: Polyethylene terephthalate (Blend of Nippon Uniperat RTj Da 3C and copolymerized polynistil 2) Stretching conditions: Stretching temperature 9g°C, 2-axis time stretching 3) Blend amount : Weight % of copolymerized polyester in the composition PO2: Oxygen gas permeation amount CG 'mW/m''
day "tm Example: The polyester copolymer obtained in Production Example 1 was entirely polyethylene terephthalate (Japan Unipet RT!; 1
Tri-blend with 90 parts of I3C) to injection mold a bottle preform, and use a biaxial stretching blow machine to reduce the internal volume to /,! ;1 (Average wall thickness of shoulder and torso 0.33m
y, its total surface fjt 700crit). When the oxygen gas permeability of the obtained bottle was measured, it was found that o, ai cc/botoiday@a
It was tm.

Comparative example S Polyethylene terephthalate (Japan Unipets nTs
ta3c) in the same manner as in Example S, the internal volumes t, s
A stretched bottle of 1 liter was molded. When the oxygen gas permeability of the obtained bottle was measured, it was 0.413cc/bottle・d
It was ay@atm.

Comparative Example 6 Polyethylene inphthalate 7 obtained in Comparative Production Example/
0 parts and polyethylene terephthalate (Japan Univeno)
M RTj+,,? C) In the same manner as in the example using 90 parts, the internal volume /, j /! The stretched bottle was completely molded. When the oxygen gas permeability of the obtained bottle was completely measured,
θ, 3q cc/bottle/day'atm was 0 Comparative Example 7 A preform for a bottle was injection molded using the polyester copolymer obtained in Production Example 1, and the content was molded using a biaxial stretching blow machine. It was formed into a stretched bottle with a volume of 7 dl. The shape of the obtained bottle was distorted and the strength of the bottle was also low.

Production Example 6 25 parts of dimethyl isophthalate, 72 parts of co-,6-naphthalene dicarboxylic acid dimethyl ester, 66 parts of ethylene glycol, and 0.5 parts of manganese acetate hydrate. Add 3 parts of θ to the reaction vessel and from /AO°C, 2, ? The temperature was gradually raised to 05G, and the transesterification reaction was carried out until no effluent was produced.

To this system, 32 parts of 3-phenylenedioxydiacetic acid, 0.0.2 parts of orthophosphoric acid, and 0.03 parts of germanium dioxide were added in this order, and the temperature was gradually raised from 3θ°C while the temperature was increased inside the polymerization tank. The pressure was gradually reduced from normal pressure to 260°C and 0. ! ;
Intrinsic viscosity is 0.7 under vacuum of torr, total polymerization time is 6 hours.
0 highly transparent polyester was obtained.

Production Example 7 Production Example except that dimethyl isophthasheet f/3 parts, /, 75 parts of 3-phenyl dioxydiacetic acid, 2,6-naphthalene dicarboxylic acid dimethyl ester 'x b s parts, and 66 parts of ethylene glycol were used. The entire polymerization was carried out in the same manner as in /. The intrinsic viscosity of the obtained polymer was 0.6 g.

Production Example G Total 29 parts of dimethyl inphthalate, 3 parts of 3-phenylenedioxydiacetic acid, 2 slI parts of 2,6-naphthalene dicarboxylic acid dimethyl ester, 7 parts of ethylene glycol
Polymerization was carried out in the same manner as in Production Example except that 3 parts were used. The intrinsic viscosity of the obtained polymer was 0.70.

Approximately 200% of the copolymerized polyester obtained in Production Example 6-g
It was pressed into a μ sheet and the oxygen permeability was completely measured. The results are summarized in Table 3.

Examples 6 to 7 The copolymerized polyester obtained in Production Examples 6 to 7 was melt-kneaded and blended with polyethylene terephthalate (Nihon Unipet Co., Ltd. RTsq3C) having a total intrinsic viscosity of 0.75 in the proportions shown in Table 2 below. The material was pressed into sheets of approximately 200μ. The oxygen permeability of the obtained pressed sheet was measured and the results are shown in Table 1.

Polyethylene terephthalate (xtT made by Nippon Unibet)
The pellets were blended at the ratios shown in Table q below (t<z3c) and injection molded (8 steel o, g.02 injection molding) to form a flat plate of Acm x 1-cyn.

The sheet was simultaneously stretched 3 times in both the longitudinal and transverse directions using a fl't long stretching machine to obtain a stretched sheet with a thickness of about 10 μm, and the oxygen permeability was completely measured. The results are summarized in Table 2.

Oxygen gas permeation amount of polyester composition') /) ~ q) Same as Table 1 Example IO 20 parts of the polyester copolymer obtained in Production Example 6 was mixed with polyethylene terephthalate) (Japan = RT&11 made by Nippet)
．． ? C) A preform for a bottle was injection molded by tri-blending with 0 parts of g, and the inner volume was 7.5 mm (average wall thickness of the shoulder and body portions: 0.33 mm) using a fully biaxial stretching blow machine. It was molded into a stretched bottle with a total surface of 700 di'. When the oxygen gas permeability of the obtained bottle was measured, it was found to be 0.2/cc/bottle/day-atm.

〔Effect of the invention〕

The polyester composition of the present invention has high transparency and excellent gas barrier properties. Therefore, the stretched sheet obtained using this method can be used for various purposes as a packaging material such as a film, sheet, cup, or tray by taking advantage of the gas barrier tl. Furthermore, the polyester hollow molded article of the present invention has not only excellent transparency and gas injection properties but also mechanical strength.
It can be used in a wide range of applications such as cosmetics. In particular, it can be used for applications such as small carbonated drinks, beer, wine, etc., where regular polyethylene phthalate biaxially stretched bottles have insufficient gas barrier properties and cannot be stored for a specified shelf life. becomes.

Claims (4)

[Claims] (1) [1] 20 to 95% by weight of polyethylene terephthalate, [2] (a) isophthalic acid or its ester-forming derivative, and (b) dicarboxylic acid represented by the following general formula (I) or its ester-forming property A polyester composition consisting of 80 to 5% by weight of a copolymerized polyester obtained by copolymerizing a dicarboxylic acid component containing a derivative with a diol component, and the ratio of (a) to (b) in the copolymerized polyester is 80 to 5% by weight. (a):(b)=1
A polyester composition characterized in that the ratio is 0 to 95:90 to 5 (mol% ratio), and the sum of (a) units and (b) units is 50 mol% or more of the total acid components of the copolymerized polyester. thing. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R represents a substituent selected from halogen, alkoxy group, phenyl group, or alkyl group. n is an integer from 0 to 4.) (2) [1] 20 to 95% by weight of polyethylene terephthalate, [2] (a) isophthalic acid or its ester-forming derivative, and (b) dicarboxylic acid represented by the above general formula (I) or its ester-forming property 80 to 5 weight of a copolymerized polyester obtained by copolymerizing a dicarboxylic acid component containing a derivative with a diol component, and the ratio of (a) to (b) in the copolyester (a):(b)=3
A polyester composition characterized in that the ratio is 0 to 90:70 to 10 (mol% ratio), and the sum of (a) units and (b) units is 50 mol% or more of the total acid components of the copolymerized polyester. thing. (3) A stretched polyester sheet obtained by stretching in at least one direction a sheet obtained by injection molding or extrusion molding the polyester composition according to claim 1. (4) A polyester hollow container formed by stretch blow molding the polyester composition according to claim 1, or forming a preform by injection molding or extrusion molding the polyester composition, and then biaxially stretch blow molding the preform.