JP2001234048A - Polyester resin composition and molded product therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition good in crystallinity and moldability, and generating only a small amount of acetaldehyde by thermal degradation. SOLUTION: This polyester resin composition comprises (A) 99-60 pts.wt. thermoplastic polyester composed of the acid component consisting of 2,6- naphthalenedicarboxylic acid, and the glycol component consisting of ethylene glycol, and (B) 1-40 pts.wt. thermoplastic polyester composed of the acid component consisting of the 2,6-naphthalenedicarboxylic acid and the glycol component consisting of tetramethylene glycol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic polyester (hereinafter abbreviated as PEN) comprising 2,6-naphthalenedicarboxylic acid unit as a main acid component and ethylene glycol as a main glycol component, The present invention relates to a polyester resin composition comprising a thermoplastic polyester (hereinafter abbreviated as PBN) having 6-naphthalenedicarboxylic acid unit as a main acid component and tetramethylene glycol as a main glycol component. For more information, see PEN
The present invention relates to a polyester resin composition having improved moldability, crystallinity, acetaldehyde content and the like.

[0002]

2. Description of the Related Art A polyester resin composition comprising PBN and PEN has a PBN / PEN = 60/40 to 99.9.
It is known in the range of 99 / 0.001 (weight ratio).

[0003] JP-A-6-107929 discloses a PB
A polyester composition comprising 60 to 95 parts by weight of N and 40 to 5 parts by weight of PEN is described.

Japanese Patent Application Laid-Open No. Hei 7-138461 discloses a PB
A composition in which PEN is blended with N resin in a ratio of 0.001 or more and less than 0.05 is described.

Japanese Patent Application Laid-Open No. 6-263851 discloses that 95 mol% or more of a dicarboxylic acid component is naphthalene-2,6-
A polyester comprising a dicarboxylic acid, wherein 95 mol% or more of the dihydroxy compound component is tetramethylene glycol and ethylene glycol, of which 95 to 60 mol% is tetramethylene glycol and 5 to 40 mol% is ethylene glycol Copolymers are described.

[0006] These conventional techniques are based on the crystallinity of PBN,
The purpose is to improve impact strength and chemical resistance.

[0007]

The present invention relates to fibers, films and sheets, resin molded articles, food packaging containers (bottles,
Containers, etc.) and non-food containers (pharmaceuticals, drinks, etc.) so that the original properties of PEN such as gas barrier properties and heat resistance are not impaired as much as possible, while improving crystallinity and moldability. Another object of the present invention is to reduce regenerated acetaldehyde due to thermal decomposition.

[0008]

That is, the present invention provides:
99 to 60 parts by weight of a thermoplastic polyester (A) containing 2,6-naphthalenedicarboxylic acid as an acid component and ethylene glycol as a glycol component, and tetramethylene glycol-containing 2,6-naphthalenedicarboxylic acid as an acid component. (B)
It is a polyester resin composition consisting of 40 parts by weight.
Hereinafter, the present invention will be described in detail.

[PEN] PEN is a thermoplastic polyester containing 2,6-naphthalenedicarboxylic acid as an acid component and ethylene glycol as a glycol component.
-It is preferred that naphthalenedicarboxylic acid is a component of 90 mol% or more of the total acid component, and ethylene glycol is a component of 90 mol% or more of the total glycol component.

[0010] PEN may contain a dicarboxylic acid other than 2,6-naphthalenedicarboxylic acid as a copolymer component, or may contain a glycol component other than ethylene glycol as a copolymer component. Further, an oxycarboxylic acid component and a compound having three or more functional groups may be copolymerized.

The intrinsic viscosity of PEN is preferably from 0.4 to
1.2, more preferably 0.5 to 1.0, and still more preferably 0.6 to 0.8. If the intrinsic viscosity is less than 0.4, physical properties such as impact strength decrease and stretch moldability decrease, which is not preferable. If the intrinsic viscosity exceeds 1.2, the productivity is poor and the stretch moldability is undesirably reduced.

[PBN] PBN is a thermoplastic polyester containing 2,6-naphthalenedicarboxylic acid as an acid component and tetramethylene glycol as a glycol component.
It is preferable that 2,6-naphthalenedicarboxylic acid is a component of 90 mol% or more of the total acid component, and tetramethylene glycol is a component of 90 mol% or more of the total glycol component.

The PBN may contain a dicarboxylic acid other than 2,6-naphthalenedicarboxylic acid as a copolymer component, or may contain a glycol component other than tetramethylene glycol as a copolymer component. . Further, an oxycarboxylic acid component and a compound having three or more functional groups may be copolymerized.

The intrinsic viscosity of PBN is preferably 0.5 to
1.5, more preferably 0.6 to 1.3, and even more preferably 0.7 to 1.2. If the intrinsic viscosity is less than 0.5, physical properties such as impact strength decrease and stretch moldability decrease, which is not preferable. If the intrinsic viscosity exceeds 1.5, the productivity is poor, which is not preferable.

[Copolymer Component] As the copolymer component of the acid component usable in PEN and / or PBN, 2,7-, 1,1,2-
5-, 1,7- and other isomers of naphthalenedicarboxylic acid; terephthalic acid; isophthalic acid; aromatic dicarboxylic acids such as diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, etc .; Alicyclic dicarboxylic acids such as hydroterephthalic acid and hexahydroisophthalic acid; aliphatic dicarboxylic acids such as adipic acid, sebacic acid and azelaic acid; oxy acids such as p-β-hydroxyethoxybenzoic acid and ε-oxycaproic acid Bifunctional carboxylic acids such as acids can be exemplified.

As a copolymer component of a glycol component usable for PEN and / or PBN, ethylene glycol,
Trimethylene glycol, tetramethylene glycol,
Hexamethylene glycol, decamethylene glycol,
Neopentyl glycol, diethylene glycol, 1,
Examples thereof include 1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2-bis (4′-β-hydroxyphenyl) propane, and bis (4′-β-hydroxyethoxyphenyl) sulfonic acid.

[Composition ratio] The composition ratio of PEN and PBN is
40 to 1 part by weight of PBN for 60 to 99 parts by weight of PEN, preferably PBN for 70 to 97 parts by weight of PEN
30 to 3 parts by weight, more preferably 75 to 95 parts by weight of PEN, and 25 to 5 parts by weight of PBN. PEN is 60
When the amount is less than parts by weight, the original properties of PEN such as heat resistance are greatly impaired. If the PBN is less than 1 part by weight, the effects of improving crystallinity, moldability and impact strength are low.

[Production Method of Polyester Resin Composition]
The polyester resin composition of the present invention can be obtained by melt-mixing EN and PBN using, for example, a single-screw extruder, a twin-screw extruder, an injection molding machine, and a film forming machine. In the melt mixing, it is preferable that the components are uniformly micro-dispersed, but the components may be partially reacted to perform block copolymerization. Therefore, the temperature at the time of melt-kneading varies depending on the kneading equipment and the mixing ratio of PEN and PBN, but it is 270 ° C.
~ 320 ° C is preferred.

[Haze / Oxygen Permeability Coefficient / Glass Transition Temperature / Acetaldehyde Content] The transparency of the polyester resin composition of the present invention is preferably not more than 10%, more preferably not more than 5%, more preferably not more than 5% as a haze value. Is not more than 2%. If the haze exceeds 10%, it is not preferable for uses requiring transparency.

The oxygen permeability of the polyester resin composition of the present invention
The excess coefficient is preferably 5 × 10^-15cm^Three・ Cm / cm^Two
・ Pa or less, more preferably 4 × 10^-15cm^Three・ Cm /
cm ^Two-It is Pa or less. Oxygen permeability coefficient is 5 × 10^-15c
m^Three・ Cm / cm^Two・ Requires gas barrier properties above Pa
This is not preferable for the intended use.

[0021] The glass transition temperature of the polyester resin composition of the present invention is preferably 80 ° C to 125 ° C, more preferably 90 ° C to 125 ° C. Glass transition temperature is 80
When the temperature is lower than 0 ° C., the polyester resin composition is used as a packaging container, and when performing heat treatment after filling the contents for the purpose of sterilization, or when filling high-temperature contents subjected to heat sterilization, deformation of the packaging container Is not preferred. Further, when a resin molded product is used, it is difficult to use it in a state where a certain temperature is applied, which is not preferable.

The content of acetaldehyde (hereinafter abbreviated as AA) of the resin composition of the present invention is preferably 30 ppm or less, more preferably 25 ppm or less, from the viewpoint of flavor when used in food applications. 30 ppm
If it exceeds 30, it is not preferable from the viewpoint of flavor.

[Additives] The polyester resin composition includes:
Fillers, lubricants, coloring agents, light stabilizers, heat stabilizers, ultraviolet absorbers, fluorescent brighteners and other various additives can be added.

Examples of the ultraviolet absorber include benzotriazole compounds, triazine compounds, benzophenone compounds, cyanoacrylate compounds, and benzoxazine compounds.

As the benzotriazole compound, 2
-(2H-benzotriazol-2-yl) -4-methylphenol, 2- (2H-benzotriazol-2-yl)
Yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2- (2H-benzotriazole-2)
-Yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazole-2)
-Yl) 4,6-bis (1,1-dimethylethyl) phenol, 2- (5-chloro-2H-benzotriazol-2-yl) -6- (1,1-dimethylethyl-4-methyl) phenol , 2- (2H-benzotriazole-
2-yl) -4,6-bis (1,1-dimethylpropyl) phenol, 2,2′-methylenebis [6- (2H
-Benzotriazol-2-yl) -4- (1,1,
3,3-tetramethylbutyl) phenol, 2- (2H
-Benzotriazol-2-yl) -6-dodecyl-4
-Methylphenol, among which 2- (2H
-Benzotriazol-2-yl) -4-methylphenol, 2- (2H-benzotriazol-2-yl)-
4,6-bis (1-methyl-1-phenylethyl) phenol is preferably used.

As the triazine compound, 2- (4,4
6-diphenyl-1,3,5-triazin-2-yl)
-5- (hexyloxy) phenol, 2- [4,6-
Bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 1,5,8,12-tetrakis [4,6-bis (N
-Butyl-N-1,2,2,6,6-pentamethyl-4
-Piperidylamino) -1,3,5-triazine-2-
Yl] -1,5,8,12-tetraazododecane, among which 2- (4,6-diphenyl-1,3,3
5-triazin-2-yl) -5- (hexyloxy)
Phenol is preferably used.

Examples of the benzophenone compound include 2-hydroxy-4-methoxy-5-sulfobenzophenone,
2-hydroxy-4-n-octoxybenzophenone,
2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone are exemplified.

As the cyanoacrylate compound, 2
-Ethylhexyl-2-cyano-3,3'-diphenyl acrylate and 2-ethyl-2-cyano-3,3'-diphenyl acrylate.

Examples of the benzoxazine-based compound include 2-
p-methoxyphenyl (3,1-benzoxazine-4
-One), 2-α-naphthyl (3,1-benzoxazin-4-one), 2-β-naphthyl (3,1-benzoxazin-4-one), 2-p-phthalimidophenyl (3,1 -Benzoxazin-4-one), 2,2'-
Bis (3,1-benzoxazin-4-one), 2,
2'-p-phenylenebis (3,1-benzoxazin-4-one), 2,2 '-(4,4'-diphenylene)
Bis (3,1-benzoxazin-4-one), 2,
2 ′-(2,6- or 1,5-naphthalene) bis (3,
1-benzoxazin-4-one) and 1,3,5-tri (3,1-benzoxazin-4-one-2-yl) benzene, among which 2,2′-bis (3
1-benzoxazin-4-one), 2,2'-p-phenylenebis (3,1-benzoxazin-4-one)
Is preferably used.

Examples of the coloring agent include oxide pigments, ferrocyanide pigments, silicate pigments, phosphate pigments, carbon black, condensed polycyclic pigments, and phthalocyanine pigments.

Examples of oxide pigments include titanium dioxide, ferric oxide (bengara), chromium oxide, cobalt blue (cobalt oxide / aluminum oxide composite oxide pigment), zinc oxide (zinc white), and lead tetroxide ( Lead red), cuprous oxide (cuprous oxide), and titanium nickel yellow.

As the ferrocyanide pigment, navy blue is exemplified.

Examples of the phosphate pigment include manganese violet.

An example of the condensed polycyclic pigment is an anthraquinone pigment.

Examples of the phthalocyanine pigment include phthalocyanine blue, metal-free phthalocyanine, phthalocyanine green, and fast sky blue.

Examples of the silicate pigment include ultramarine blue, talc, and white carbon. Preferred examples of the white carbon include silicic anhydride, hydrous silicic acid, hydrous magnesium silicate, hydrous calcium silicate, and hydrous aluminum silicate.

Examples of the heat stabilizer (antioxidant) include monophenol-based, bisphenol-based, polymer-type phenol-based, and phosphorus-based heat stabilizers.

As monophenols, 2,6-di-
t-butyl-p-cresol, butylhydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-tert-butyl-4-
(Hydroxyphenyl) propionate. Among them, stearyl-β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate is preferred.

The bisphenols include 2,2'-methylenebis (4-methyl-6-t-butylphenol) and 2,2'-methylenebis (4-ethyl-6-t-
Butylphenol), 4,4′-thiobis (3-methyl-6-t-butylphenol) and 4,4′-butylidenebis (3-methyl-6-t-butylphenol).

As the polymer type phenol, 1,1,1
3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,
4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3-
(3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane and α-tricolor. Among them, tetrakis- [methylene-3-
(3 ′, 5′-Di-tert-butyl-4′-hydroxyphenyl) propionate] methane is preferred.

Examples of the phosphorus system include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl ditridecyl) phosphite, and cyclic. Neopentanetetraylbis (octadecylphosphite), tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,4-di-t-) Butylphenyl)
Phosphite and cyclic neopentanetetraylbis (2,6-di-tert-butyl-4-methylphenyl) phosphite.

Among them, cyclic neopentanetetraylbis (octadecylphosphite), tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetrayl Ilbis (2,4-di-tert-butylphenyl) phosphite is preferred.

Examples of the light stabilizer include hindered amine light stabilizers, such as Tinuvin-622 from Ciba Specialty Chemicals, and ADK STAB LA-57, LA77, LA67 from Asahi Denka. Can be

[Molded Article] The molded article made of the polyester resin composition of the present invention is, for example, a hollow molded article, a film, a sheet, or a resin molded article. These molded articles may be composed of a single layer. It may be composed of multiple layers. In the case of a multilayer structure, the molded body includes a surface layer and an intermediate layer. The polyester resin composition of the present invention may be used for a surface layer or an intermediate layer.

[Manufacturing Method of Molded Body] As a method of manufacturing a hollow molded body, a hot parison method in which an injection unit and a blow unit are integrated, a cold parison method in which an injection unit and a blow unit are separate equipment, a direct method, Examples of the method include a blow method, an injection blow method, an extrusion blow method, and a method of forming a sheet and a film and then performing thermoforming.

Examples of the method for producing a film and a sheet include a method for forming a non-stretched film and sheet from a single-screw or twin-screw extruder, a method for uniaxially and / or biaxially stretching, and an inflation molding method. .

Examples of the method for molding the resin molded body include injection molding, gas injection molding, extrusion molding, and compression molding.

[0048]

The present invention will be described below in more detail with reference to examples. The characteristics in the examples were measured by the following methods.

(1) Haze For a bottle, a thickness of 300 μm from the body of the bottle, and for a sheet film, from an arbitrary position of the sheet film.
m (bottle), 150 μm (sheet), and 20 μm (film) samples were cut out from Nippon Denshoku Koro Co., Ltd.
r and color difference met
er (MODEL1001DP).

(2) Glass transition temperature (Tg), crystallinity (Tci), intrinsic viscosity (IV), AA content In the case of a bottle, a sample was cut out from the mouth of the bottle. Tg and Tci are DuPont DSC (MOD
EL2200) at a heating rate of 5 ° C./min. Was measured. IV was measured at 25 ° C. with tetrachloroethane: phenol = 4: 6 (weight ratio). The AA content was measured by freezing and pulverizing the sample, charging the sample in a vial bottle, holding at 150 ° C. × 60 minutes, and using headspace gas chromatography manufactured by Hitachi.

(3) Oxygen gas barrier property A sheet sample having a thickness of 150 μm (unstretched), a thickness of 20
Using a μm film (stretched), it was measured with a gas permeability meter K-315N manufactured by Rika Seiki Kogyo Co., Ltd. (25
° C).

(4) Production of thermoplastic polyester (A) Thermoplastic polyester (A) was produced by the method of the following Reference Example.

[Reference Examples 1 and 2] 100 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester and 70 parts by weight of ethylene glycol were used, and cobalt acetate, calcium acetate and magnesium acetate were used as transesterification catalysts. The ester exchange reaction was carried out while distilling out the system and heating to 250 ° C., and at the stage when methanol was almost completely distilled off, germanium acetate was added as a polymerization catalyst, and subsequently trimethyl phosphate was added as a stabilizer, The transesterification was terminated. Next, the reaction product was subjected to a polycondensation reaction under high temperature and high vacuum to obtain a prepolymer having an intrinsic viscosity of 0.50 (a mixed solvent of 2 parts by weight of tetrachloroethane and 3 parts by weight of phenol at 25 ° C.). After making this prepolymer into a strand type chip, it was further subjected to solid phase polymerization under heating and vacuum, and the intrinsic viscosity (a mixed solvent of 2 parts by weight of trichlorophenol and 3 parts by weight of phenol at 35 ° C.) 0.65 (Reference Example 1) ) And 0.78 (Reference Example 2) as a solid-phase polymerized thermoplastic polyester (A).

[Reference Examples 3 and 4] 100 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester and 70 parts by weight of ethylene glycol were used as a transesterification catalyst with cobalt acetate and manganese acetate, and methanol produced as a by-product was removed from the system. At the stage of distilling off, antimony trioxide was added as a polymerization catalyst, and a transesterification reaction was performed while heating to 250 ° C., and at the stage where methanol distillation was almost completed, orthophosphoric acid was added as a stabilizer. Then, the transesterification reaction was terminated. Next, the reaction product is subjected to a polycondensation reaction under high temperature and high vacuum to obtain an intrinsic viscosity (a mixed solvent of 2 parts by weight of tetrachloroethane and 3 parts by weight of phenol at 25 ° C.) of 0.5.
0 was obtained. After making this prepolymer into a strand type chip, it was further subjected to solid phase polymerization under heating and vacuum to have an intrinsic viscosity (a mixed solvent of 2 parts by weight of trichlorophenol and 3 parts by weight of phenol at 35 ° C.) of 0.62 (Reference Example 3). ) And 0.69 (Reference Example 4) as a solid-phase polymerized thermoplastic polyester (A).

Reference Example 5 93 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester, 5.4 parts by weight of dimethyl terephthalate, and 70 parts by weight of ethylene glycol were prepared by using cobalt acetate and manganese acetate as transesterification catalysts. The produced methanol is distilled out of the system and 250
The ester exchange reaction was carried out while heating to ℃ C, and at the stage when methanol was almost completely distilled off, antimony trioxide was added as a polymerization catalyst, and orthophosphoric acid was subsequently added as a stabilizer to terminate the transesterification reaction. Was. Then
The reaction product was subjected to a polycondensation reaction under high temperature and high vacuum to obtain a prepolymer having an intrinsic viscosity of 0.56 (a mixed solvent of 2 parts by weight of tetrachloroethane and 3 parts by weight of phenol at 25 ° C.). After making this prepolymer into a strand type chip, it is further subjected to solid phase polymerization under heating and vacuum to obtain an intrinsic viscosity (a mixed solvent of 2 parts by weight of trichlorophenol and 3 parts by weight of phenol,
(35 ° C.) A thermoplastic polyester as a solid-state polymerized polymer (Reference Example 5) of 0.72 was obtained.

(5) Production of thermoplastic polyester (B) A thermoplastic polyester (B) was produced by the method of the following Reference Example.

Reference Examples 6 and 7 100 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester and 65 parts by weight of tetramethylene glycol were used as catalysts, and methanol produced as a by-product was removed from the system. The ester exchange reaction is carried out while distilling off and heating to 210 ° C., and then the reaction product is subjected to a polycondensation reaction under high temperature and high vacuum to obtain an intrinsic viscosity (a mixed solvent of 2 parts by weight of tetrachloroethane and 3 parts by weight of phenol, (25 ° C.) 0.75 polymer (Reference Example 6) was obtained. This polymer was made into a strand type chip, and further subjected to solid phase polymerization under heating and vacuum to obtain a polymer having an intrinsic viscosity (a mixed solvent of 2 parts by weight of tetrachloroethane and 3 parts by weight of phenol at 25 ° C.) of 1.10. 7) was obtained.

Example 1 99 parts by weight of the thermoplastic polyester (A) obtained in Reference Example 1 and 1 part by weight of the thermoplastic polyester (B) obtained in Reference Example 6 were mixed with an injection molding machine (M -100DM) (cylinder setting 300 ° C, screw rotation speed 160rpm, molding cycle 30sec)
c) The mixture was melt-kneaded to obtain a preform weighing 55 g. This preform is continuously used for KRUPP CORPOPL
Blow-molded with AST-01 LB01, bottle is about 1.5L (liter) in volume and average body thickness is about 300μm
Met. The resulting bottle was evaluated. Table 1 shows the results.

[Examples 2 to 10, Comparative Examples 1 and 2] In the same manner as in Example 1, bottles were molded from the thermoplastic polyester resin compositions shown in Table 1 and evaluated. Table 1 shows the results.

[0060]

[Table 1]

Example 11 95 parts by weight of the thermoplastic polyester (A) obtained in Reference Example 1 and 5 parts by weight of the thermoplastic polyester (B) obtained in Reference Example 6 were mixed with a film forming machine (at a cylinder setting of 275). To 305 ° C.) to obtain a sheet (having a thickness of about 150 μm). Subsequently, a film having a thickness of about 20 μm was obtained by molding with a long stretching machine. The obtained sheets and films were evaluated. Table 2 shows the results.

Examples 12 to 14 In the same manner as in Example 11, sheets and films were formed from the thermoplastic polyester resin compositions shown in Table 2. The obtained sheets and films were evaluated. Table 2 shows the results.

[0063]

[Table 2]

[0064]

According to the present invention, it is possible to provide a polyester resin composition having good crystallinity and moldability and having a small amount of acetaldehyde regenerated by thermal decomposition.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B65D 1/00 BF Term (Reference) 3E033 AA20 BA17 BB04 BB05 BB08 CA07 CA16 GA02 GA03 3E086 AB01 BA04 BA15 BB01 BB41 4F071 AA45 AA86 AF08Y AF30Y AH05 AH19 BB06 BC01 BC04 BC07 4J002 CF081 CF082 EE016 FD040 FD050 FD060 FD090

Claims (11)

[Claims] 1. A thermoplastic polyester (A) comprising 2,6-naphthalenedicarboxylic acid as an acid component and ethylene glycol as a glycol component in an amount of 99 to 60 parts by weight;
A polyester resin composition comprising 1 to 40 parts by weight of a thermoplastic polyester (B) containing naphthalenedicarboxylic acid as an acid component and tetramethylene glycol as a glycol component. 2. The polyester resin composition according to claim 1, wherein the haze is 10% or less. 3. The polyester resin composition according to claim 1, wherein the acetaldehyde content is 30 ppm or less. 4. An oxygen permeability coefficient of 5 × 10 ⁻¹⁵ cm ³ · cm
The polyester resin composition according to claim 1, which is not more than / cm ² · Pa. 5. The polyester resin composition according to claim 1, wherein the glass transition temperature is from 80 ° C. to 125 ° C. 6. A molded article comprising the polyester resin composition according to claim 1. 7. The molded article according to claim 6, which is a hollow molded article. 8. The molded article according to claim 6, which is a sheet. 9. The molded article according to claim 6, which is a film. 10. A multilayer molded article having a surface layer, wherein the surface layer is made of the polyester resin composition according to claim 1. 11. A multilayer molded article having an intermediate layer,
A multilayer molded article in which the intermediate layer comprises the polyester resin composition according to claim 1.