JP2001064495A - Polyester resin composition and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having a good sliding property and also excellent in heat-sealing property while maintaining a gas barrier property, etc., by blending a specific polyester resin with inorganic particles under a specific condition. SOLUTION: This polyester resin composition is obtained by incorporating (A) a polyester resin consisting mainly of a diol unit consisting mainly of ethylene glycol unit with dicarboxylic acid unit consisting mainly of terephthalic acid unit and containing 7.5-20 mole % isophtahlic acid unit in the total structural units and (B) inorganic particles having >=5 μm particle diameter in an amount of satisfying the formula: logY>31ogX-0.75X [X is the mean particle diameter (μm) of the component B; Y is an added amount (pt.wt.) of the component B based on 100 pts. wt. component A], and preferably satisfies the formula: -6<=(1/2)log(η2/η1)<=-0.3 [η1, η2 are each melt viscosity (poise) of the polyester resin composition at 270 deg.C under 1 rad/sec and 100 rad/sec shearing speeds].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyester resin composition and its use. The polyester resin composition of the present invention gives a molded article having excellent mechanical properties such as heat sealing properties, flavor barrier properties, slip properties (slip properties), elongation and strength, and specifically as a film or packaging material.
Further, it is effectively used as an inner surface coating material of paper containers, a laminate, and the like.

[0002]

2. Description of the Related Art The disposal of used plastic containers has become a major social problem, and in view of this, there has been an increasing demand for paper containers that can be incinerated and recycled relatively easily as compared with plastic containers. This is not an exception in the field of beverage containers such as juice containers. For containers such as juice, for example, paper containers whose inner surfaces are coated with a resin film are generally widely used. In that case, an olefin resin is generally used as the resin film coated on the inner surface of the paper container, but the paper container coated on the inner surface with the olefin resin contains an aroma component such as a fruit juice beverage. When used in a paper container, problems such as loss of aroma and change in taste may occur.

[0003] Therefore, it has been proposed to coat a polyester resin laminate having a modified polyethylene terephthalate layer containing about 5 to 20 mol% of a copolymer component unit on the inner surface of a paper container instead of the olefinic resin ( JP-A-3-133638). In this case, the fragrance and taste of the beverage or the like filled in the paper container can be kept to some extent due to the inherent properties of the polyester resin such as gas barrier properties and flavor barrier properties. However,
In the production of paper containers, a method in which a carton sleeve is formed from a laminate in which a resin film is coated on a paper stock and the box is formed into a paper container is widely used. Since the coating layer has low slipperiness, the stacked carton sleeves come into close contact with each other, causing problems such as an increase in the rate of defective products in the box making process.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester resin having good lubricity when molded into a film or the like while maintaining good properties such as gas barrier properties and flavor barrier properties. It does not cause problems such as defective products in the box making process, and has excellent heat sealability, and can be firmly and smoothly bonded and laminated to paper and other base materials, elongation and strength etc. An object of the present invention is to provide a polyester resin composition having excellent mechanical properties and excellent handling properties. Another object of the present invention is to provide a use of the above-mentioned polyester resin composition. More specifically, a film made of the above-mentioned polyester resin composition is utilized by utilizing the excellent properties of the above-mentioned polyester resin composition. Or, molded articles such as packaging materials such as beverage containers containing flavor components such as fruit juice beverages, inner surface coating materials of paper containers made of the composition, and paper containers having layers and paper layers made of the composition. It is to provide a laminate.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, a polyester obtained by blending inorganic particles under a specific condition with a polyethylene terephthalate resin copolymerized with isophthalic acid. Molded articles such as films obtained from the resin composition have good slip properties while maintaining good properties such as gas barrier properties and flavor barrier properties inherent in polyester resins, and have excellent heat sealing properties. Can be firmly and smoothly bonded and laminated to a substrate such as paper, and has excellent mechanical properties such as elongation and strength, and the polyester resin composition or a film comprising the same is a fruit juice. To find that it is effective as a packaging material for containers used for beverages and other foods or as an inner coating material for paper containers, etc. Was Tsu.

That is, the present invention is based on (A) a diol unit mainly composed of an ethylene glycol unit and a dicarboxylic acid unit mainly composed of a terephthalic acid unit, and an isophthalic acid unit based on the total number of moles of all structural units. A composition containing 7.5 to 20 mol% of a polyester resin and (B) inorganic particles having a particle size of 5 μm or more, wherein the inorganic particles are contained in an amount satisfying the following formula (1). A polyester resin composition characterized by the following.

LogY> 3logX−0.75X (1)

In the formula, X represents the average particle size (μm) of the inorganic particles, and Y represents the amount (parts by weight) of the inorganic particles added to 100 parts by weight of the polyester resin.

The present invention is also a molded article such as a film made of the above polyester resin composition, a packaging material such as a container, and a coating material for an inner surface of a paper container. Furthermore, the present invention is a laminate having a layer made of the polyester resin composition and a paper layer.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester resin which is the main component of the polyester resin composition of the present invention is mainly composed of a diol unit mainly composed of an ethylene glycol unit and a dicarboxylic acid unit mainly composed of a terephthalic acid unit. The unit is 7.5 to 20 with respect to all structural units.
Mol%. When the amount of isophthalic acid units is less than 7.5 mol%, the heat sealability of the film becomes poor, and when the amount of isophthalic acid units exceeds 20 mol%, mechanical properties such as elongation deteriorate. . From the viewpoint of improving the heat sealing property of the film and maintaining the mechanical properties of the film, the content of the isophthalic acid unit in the polyester resin is preferably in the range of 10 to 15 mol%.

The above-mentioned polyester resin may have another structural unit as long as the properties such as the heat sealing property, the gas barrier property and the flavor barrier property of the film are not impaired. Other structural units include, for example, diol units derived from diols such as diethylene glycol, 1,4-butanediol, and polyethylene glycol (preferable molecular weight: 400 to 30,000); aromatic dicarboxylic acids such as paraphenylenedicarboxylic acid and sulfoisophthalic acid And dicarboxylic acid units derived from aliphatic dicarboxylic acids such as acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid and sebacic acid or ester-forming derivatives thereof. It may be the above. In general, the proportion of the other structural units in the polyester resin is preferably about 5 mol% or less based on the total moles of all the structural units in the polyester resin.

The polyester resin may contain a structural unit derived from a trifunctional or higher polyfunctional compound such as trimellitic acid, trimethylolpropane or pentaerythritol, as long as the thermoplasticity is not substantially impaired. Good.

The intrinsic viscosity [η] of the polyester resin used in the present invention (measured in a phenol / tetrachloroethane mixed solvent of equal weight at 30 ° C.) is determined from the viewpoint of moldability to a film or the like and mechanical strength of a molded article. 0.60 to 1.50d
It is preferably in the range of 1 / g.

The polyester resin composition of the present invention contains inorganic particles having an average particle size of 5 μm or more. When the average particle size of the inorganic particles is less than 5 μm, it is necessary to add a large amount of inorganic particles in order for a molded article such as a film to substantially exhibit slipperiness. There is a problem that physical properties are deteriorated. Examples of the inorganic particles include silica, alumina, titanium dioxide, calcium carbonate, barium sulfate, and the like. Silica is preferred from the viewpoint of maintaining the mechanical strength of the film and coloring.

The average particle size and the amount of the inorganic particles need to satisfy the above formula (1). When the average particle size and the amount of the inorganic particles do not satisfy the formula (1), the molded article such as a film obtained from the polyester resin composition does not sufficiently exhibit slipperiness, and the coating layer formed from the composition has In the box making process of a paper container having the same, a problem such as an increase in the rate of defective products occurs.

The polyester resin used in the present invention can be produced according to a method generally employed for producing a general-purpose polyester resin such as polyethylene terephthalate. For example, an esterification reaction or transesterification is performed using a polyester-forming raw material comprising a dicarboxylic acid component mainly composed of dicarboxylic acid or a lower alkyl ester thereof mainly composed of terephthalic acid and isophthalic acid and a diol component mainly composed of ethylene glycol. After the reaction, the resulting low polymer is melt-polycondensed into a polyester, and further, if desired, after the polyester is formed into chips or pellets of any shape,
By performing solid phase polymerization, a polyester resin having an improved degree of polymerization can be obtained.

The above esterification reaction is carried out at about 230-280 ° C. under a pressure of 3 kg / cm ² or less at normal pressure or absolute pressure.
It is preferred to carry out at a temperature of In this case, the ratio of the dicarboxylic acid component and the diol component used is 1: 1 to 1 for the latter.
A range of 1: 1.5 (molar ratio) is preferable.

The transesterification reaction is preferably carried out at about 170 to 230 ° C. under normal pressure or near normal pressure. In this case, the use ratio of the dicarboxylic acid component and the diol component is preferably in a range where the former to the latter is 1: 1 to 1: 3 (molar ratio). Examples of the catalyst used in the transesterification reaction include titanates such as tetraisopropyl titanate, tetrabutyl titanate, and tetrastearyl titanate which have been conventionally used as transesterification catalysts.

The above-mentioned melt polycondensation reaction is usually carried out at a temperature of about 260 to 290 ° C. in the presence of a polycondensation catalyst such as germanium dioxide or antimony trioxide. By such a melt polycondensation reaction, the limiting viscosity [η] is usually 0.50 to 1.
50 dl / g of polyester are obtained. Further, when the melt polycondensation reaction is performed in the presence of a phosphorus compound such as phosphoric acid, phosphorous acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, and triphenyl phosphate, the resulting polyester may be colored by thermal decomposition or A decrease in molecular weight during melt molding can be prevented.

The above esterification reaction, transesterification reaction and polycondensation reaction may be carried out, if necessary, by adding a diethylene glycol by-product inhibitor such as tetraammonium hydroxide, triethanolamine or triethylamine. .

The polyester obtained by the melt polycondensation reaction is generally formed into chips or pellets, and if desired, may be pre-crystallized at a temperature of 190 ° C. or lower, and then subjected to solid-phase polymerization to improve the degree of polymerization. it can. The solid-state polymerization reaction is usually performed by heating to about 190 to 240 ° C. under a reduced pressure or under a flow of an inert gas such as a nitrogen gas while flowing the chips (pellets) so as not to fuse each other.
The polyester resin having a desired intrinsic viscosity used in the present invention can be obtained by the above-described series of reaction steps.

The polyester resin composition of the present invention is prepared by a method capable of uniformly dispersing inorganic particles in a polyester resin. As such a preparation method, for example, (1)
A method of adding inorganic particles during the production of a polyester resin,
(2) A method in which a polyester resin chip and inorganic particles are melt-mixed to prepare a master batch in advance, and the master batch is added to the polyester resin at the time of manufacturing a molded article.

The polyester resin composition of the present invention may contain conventionally known various additives depending on the use and the like as long as the effects of the present invention are not impaired. Examples of such additives include a hydrolysis inhibitor, a colorant, a flame retardant, an antioxidant, an ultraviolet absorber, an antistatic agent, and a lubricant. When the polyester resin composition of the present invention is used as an inner coating material for a food paper container that comes into direct contact with food, it is necessary to select the above additives in consideration of safety.

The polyester resin composition of the present invention can be heated and melted into various molded articles such as films, sheets, plate-like bodies, tubular bodies, hollow molded articles, molded articles, and laminated articles. As the molding method, any of the molding methods used for molding a thermoplastic resin can be used, for example, an extrusion molding method, a casting molding method, an extrusion blow molding method, an injection molding method, an injection blow molding method, a calendar molding method. Press molding method, various lamination molding methods, and the like.

Among the above-mentioned molded articles, the polyester resin composition of the present invention is formed into packaging films and sheets, bottles and other types of packaging containers, and especially when used as food films and sheet containers. In addition, good gas barrier properties, flavor barrier properties, heat sealing properties, mechanical properties, etc. are effectively exhibited. When a film or sheet is formed from the polyester resin composition of the present invention, its thickness is not particularly limited and may be appropriately set depending on the application and the like, but is generally about 0.005 to 1 mm. Is preferred.

As a method for forming a film or a sheet from the polyester resin composition of the present invention, any of the conventionally known methods for producing a film or a sheet using a thermoplastic resin can be applied. An inflation extrusion molding method, a calendar molding method, a press molding method, etc., in which molding is performed while introducing a fluid into a cylindrical body extruded using an annular die, are employed. Among them, in order to industrially produce a large amount of films, it is preferable to employ an extrusion molding method because of easy molding, low product loss and low production cost. When the film is manufactured by the inflation extrusion molding method, the stretched film is adjusted by adjusting the pressure and amount of the fluid introduced into the cylindrical body extruded from the annular die, the take-up speed of the extruded film, and the like. Can be obtained.

When a film is molded by an extrusion molding method using a T-die, if the melt viscosity of the resin is small, the molten film extruded from the die may be sagged or neck-in when the film is taken up by a roll or the like. Molding defects such as a decrease in film width and a film shake phenomenon occur. Also, when a film is formed by the inflation extrusion molding method, if the melt viscosity of the resin is small, a molding defect such as a dripping of a molten cylindrical body extruded from an annular die occurs. These molding defects cause unevenness of thickness, perforation, cutting, etc. of the film, and significantly reduce productivity. Therefore, when a film is molded by a T-die extrusion molding method or an inflation extrusion molding method, the following formula is used. It is preferable to adjust the melt viscosity of the polyester resin composition so as to satisfy (2).

-0.6 ≦ (1/2) log (η2 / η1) ≦ −0.3 (2)

In the formula, η1 and η2 are respectively the shear rate at 270 ° C. of the polyester resin composition of 1 rad /
Shows the melt viscosity (poise) in seconds and 100 rad / sec.

The film or sheet comprising the polyester resin composition of the present invention can be in the form of a laminate of two or more layers with another substrate. As a material constituting another substrate, for example, polyolefin such as polyethylene or polypropylene, polyamide, polyvinyl chloride,
Examples thereof include polyvinylidene chloride, polyesters other than the polyester used in the present invention, thermoplastic polymers such as ethylene-vinyl alcohol copolymer, paper, cloth, and metal foil. One or more of these substrates are used. The method for preparing the laminate is not particularly limited, and for example, a conventionally known method such as an extrusion lamination method, a dry lamination method, a wet lamination method, and a hot melt lamination method is employed.

The laminate obtained by laminating a film layer made of the polyester resin composition of the present invention on a paper material has excellent slipperiness. Since it does not cause odor and is excellent in flavor barrier properties and heat sealing properties, it can be effectively used as a juice container or other paper container material for beverages.

[0032]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto. In the following Examples and Comparative Examples, the intrinsic viscosity of the polyester resin, the melt viscosity of the polyester resin composition, the slipperiness of the film obtained from the polyester resin composition, heat sealability, tensile strength, tensile elongation and flavor barrier properties are Was measured or evaluated as follows.

(1) Intrinsic viscosity of polyester resin: 30 ° C. in a mixed solvent of phenol / tetrachloroethane and the like.
Was measured using a Ubbelohde viscometer (“HRK-3” manufactured by Hayashi Seisakusho).

(2) Melt viscosity of the polyester resin composition: The polyester resin and the inorganic particles are melt-kneaded at 270 ° C. using a twin screw extruder (“TEX30SS-30CRW-2V” manufactured by Nippon Steel Works) to form a strand. And cut to prepare a cylindrical polyester resin composition chip. The obtained chip was measured with a mechanical spectrometer (“RMS-800” manufactured by Rheometrics).
Shear rate 1 at 270 ° C using a parallel plate
melt viscosity at rad / sec (η1) (poise), and 2
The melt viscosity (η1) (poise) at a shear rate of 100 rad / sec at 70 ° C. was measured.

(3) Film slip properties: The polyester resin composition chips obtained in (2) above were melted at 270 ° C. in a melt extruder (“Laboplast Mill” manufactured by Toyo Seiki Co., Ltd.) and directly connected to T. Die (width 30cm, lip thickness 0.3m)
m) and extruded on a cooling roll at 60 ° C.
m, a film having a width of 25 cm was prepared. Using the obtained film, the coefficient of kinetic friction was measured according to JIS-K7125 and used as an index of slip property. Unmeasurable indicates that there is substantially no slip property.

(4) Heat sealing property of the film: Using a film obtained by the same method as in the above (3), using a heat sealer (“YSS type heat sealer” manufactured by Yasuda Seiki Seisaku-sho, Ltd.), the sealing pressure is 1.2 kg. Heat sealing was performed under the conditions of / cm ² and a sealing time of 1.4 seconds, and the lower limit temperature at which heat sealing was possible was determined, and this was used as an index of heat sealing properties.

(5) Tensile strength and tensile elongation of the film: Using a film obtained in the same manner as in the above (3), a test piece of 80 mm long × 15 mm wide is cut out from the film, and the tensile strength is measured according to ASTM D882. And the tensile elongation were measured.

(6) Flavor barrier properties of the film:
Using a film obtained in the same manner as in the above (3), a test piece having a length of 20 mm and a width of 50 mm was cut out from the film, and the cut piece was heated at 25 ° C. in 50 ml of orange juice (Ehime mandarin orange “POM straight juice”). 12
After soaking for a day, the film was taken out of the orange juice, and the amount of limonene remaining in the orange juice was quantified by bromination titration to give an index of flavor barrier properties.

Example 1 80 parts by weight of terephthalic acid, 20 parts by weight of isophthalic acid and 45 parts by weight of ethylene glycol were mixed to form a slurry, and the slurry was subjected to an esterification reaction at a temperature of 250 ° C. A mixture of 95% bishydroxyethyl terephthalate, bishydroxyethyl isophthalate and their low polymers was prepared.

Next, 0.046 parts by weight of antimony trioxide as a catalyst was added to 124 parts by weight of the above mixture, and a polycondensation reaction was carried out at 280 ° C. under a reduced pressure of 1 Torr absolute to obtain an intrinsic viscosity [η]. 0.90 dl / g polyester was prepared. This polyester is extruded into a strand from a nozzle, cut and cut to a length of 3.2 mm and a diameter of 2.8 mm.
Was manufactured.

To 100 parts by weight of the above chips, 0.05 part by weight of silica having an average particle size of 5.2 μm was added, and a twin screw extruder (“TEX30SS-30CRW-2” manufactured by Nippon Steel Works, Ltd.) was added.
V "), the mixture was melt-kneaded at 270 ° C, extruded into strands, and cut to produce columnar chips of 3.2 mm in length and 2.8 mm in diameter made of polyester resin and silica.

The obtained chip was melted at 270 ° C. in a melt extruder (“Laboplast Mill” manufactured by Toyo Seiki Co., Ltd.), and the melt was extruded from a directly connected T-die (width 30 cm, lip thickness 0.3 mm) to 60.
Extruded on a cooling roll at 30 ° C., thickness 30 μm, width 25 cm
Was prepared. The dynamic friction coefficient, heat sealability, tensile strength, tensile elongation and flavor barrier properties of the obtained film were measured or evaluated, and the results are shown in Table 1.

Example 2 An esterification reaction was carried out in the same manner as in Example 1 except that 70 parts by weight of terephthalic acid, 30 parts by weight of isophthalic acid and 45 parts by weight of ethylene glycol were mixed to form a slurry.
Polycondensation reaction and chip preparation were performed to obtain polyester chips having an intrinsic viscosity [η] of 0.98 dl / g.

A columnar chip was prepared in the same manner as in Example 1 except that 0.02 parts by weight of silica having an average particle diameter of 8.0 μm was added to 100 parts by weight of the above chip, and then the chip was used. A film was produced. The kinetic friction coefficient, heat sealability, tensile strength, tensile elongation, and flavor barrier properties of the obtained film were measured or evaluated, and the results are shown in Table 1.

Comparative Example 1 Example 1 was repeated except that the amount of silica was changed to 0.01 part by weight.
A film was produced in the same manner as described above. Measure or evaluate the dynamic friction coefficient, heat sealability, tensile strength, tensile elongation and flavor barrier properties of the obtained film,
The results are shown in Table 1.

Comparative Example 2 A film was produced in the same manner as in Example 1 except that silica having an average particle size of 1.4 μm was used. The dynamic friction coefficient, heat sealability, tensile strength, tensile elongation and flavor barrier properties of the obtained film were measured or evaluated, and the results are shown in Table 1.

Comparative Example 3 An esterification reaction was carried out in the same manner as in Example 1 except that 90 parts by weight of terephthalic acid, 10 parts by weight of isophthalic acid and 45 parts by weight of ethylene glycol were mixed to form a slurry.
Polycondensation reaction and chip preparation were performed to obtain polyester chips having an intrinsic viscosity [η] of 0.82 dl / g.

Next, using the above-mentioned chip, Example 1
A film was produced in the same manner as described above. Measure or evaluate the coefficient of kinetic friction, heat sealability, tensile strength, tensile elongation and flavor barrier properties of the obtained film,
The results are shown in Table 1.

Comparative Example 4 An esterification reaction was carried out in the same manner as in Example 1 except that 50 parts by weight of terephthalic acid, 50 parts by weight of isophthalic acid and 45 parts by weight of ethylene glycol were mixed to form a slurry.
Polycondensation reaction and chip preparation were performed to obtain polyester chips having an intrinsic viscosity [η] of 1.03 dl / g.

Next, Example 1 was performed using the above-mentioned chip.
A film was produced in the same manner as described above. Measure or evaluate the coefficient of kinetic friction, heat sealability, tensile strength, tensile elongation and flavor barrier properties of the obtained film,
The results are shown in Table 1.

Comparative Example 5 Esterification reaction and polymerization were carried out in the same manner as in Example 1 except that 100 parts by weight of terephthalic acid, 34 parts by weight of ethylene glycol and 26 parts by weight of 1,4-cyclohexanedimethanol were mixed to form a slurry. A condensation reaction and chip preparation were performed to obtain polyester chips having an intrinsic viscosity [η] of 0.82 dl / g.

Next, Example 1 was performed using the above-mentioned chip.
A film was produced in the same manner as described above. Measure or evaluate the coefficient of kinetic friction, heat sealability, tensile strength, tensile elongation and flavor barrier properties of the obtained film,
The results are shown in Table 1.

[0053]

[Table 1]

In Table 1, PET means polyethylene terephthalate, IPA means isophthalic acid, and CHDM means 1,4-cyclohexanedimethanol.

From Table 1, it is found that isophthalic acid was prepared by adding inorganic particles having an average particle diameter of 5 μm or more to a polyethylene terephthalate resin copolymerized with 7.5 to 20 mol% so as to satisfy the above formula (1). It can be seen that the films obtained from the obtained polyester resin compositions of Examples 1 and 2 have good slipperiness, heat sealability, tensile strength, tensile elongation and flavor barrier properties.

On the other hand, from the results of Comparative Example 1, when the relationship between the average particle diameter and the content of silica does not satisfy the above formula (1), the obtained film has poor slipperiness, and Comparative Example 2
It can be seen from the results that when the average particle size of the silica is less than 5 μm, the obtained film has a low tensile elongation. Also, from the results of Comparative Example 3, when the copolymerization amount of isophthalic acid was small outside the range of 7.5 to 20 mol%, the obtained film was inferior in heat sealability. The copolymerization amount of the acid is 7.5 to 20 mol%
When the film is out of the range, the obtained film has a low tensile elongation. Furthermore, the results of Comparative Example 5 show that when the copolymerization component was 1,4-cyclohexanedimethanol instead of isophthalic acid, the obtained film had low flavor barrier properties.

Example 3 An ester was prepared in the same manner as in Example 1 except that 80 parts by weight of terephthalic acid, 20 parts by weight of isophthalic acid, 0.0006 parts by weight of trimellitic acid and 45 parts by weight of ethylene glycol were mixed to form a slurry. Reaction, polycondensation reaction and chip preparation, the limiting viscosity [η] is 1.01 dl / g
Polyester chips were obtained.

Next, 0.05 parts by weight of silica having an average particle size of 5.2 μm was added to 100 parts by weight of the chips, melt-kneaded in the same manner as in Example 1, extruded into strands, and cut. Then, a columnar chip made of a polyester resin and silica and having a length of 3.2 mm and a diameter of 2.8 mm was manufactured. The melt viscosity of the obtained chips was measured, and the results are shown in Table 2.

Further, a film was produced in the same manner as in Example 1 using the above chips. The dynamic friction coefficient, heat sealability, tensile strength, tensile elongation and flavor barrier properties of the obtained film were measured or evaluated, and the results are shown in Table 2.

[0060]

[Table 2]

[0061]

According to the polyester resin composition of the present invention, the molded article has good slipperiness while maintaining good properties such as gas barrier property and flavor barrier property inherent in the polyester resin. There is little occurrence of defective products due to the close contact between the carton sleeves, extremely excellent process passability, and excellent heat sealability, and it can be firmly and smoothly adhered and laminated to paper and other base materials. Excellent in mechanical properties such as degree and strength, and excellent in handling. Films provided by the present invention, molded articles such as packaging materials such as beverage containers containing aroma components such as fruit juice beverages, laminates such as paper container inner surface coating materials and paper containers, the polyester resin composition described above Express the excellent performance of

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Claims (5)

[Claims] 1. (A) It is mainly composed of a diol unit mainly composed of an ethylene glycol unit and a dicarboxylic acid unit mainly composed of a terephthalic acid unit, and the isophthalic acid unit is 7.5 to 7.5 based on the total number of moles of all the structural units. A composition comprising a polyester resin containing 20 mol% and (B) inorganic particles having a particle diameter of 5 μm or more, wherein the inorganic particles are contained in an amount satisfying the following formula (1). Polyester resin composition. logY> 3logX-0.75X (1) (wherein, X represents the average particle size (μm) of the inorganic particles, and Y represents the amount (parts by weight) of the inorganic particles added to 100 parts by weight of the polyester resin.) 2. The polyester resin composition according to claim 1, which satisfies the following formula (2). −0.6 ≦ (1/2) log (η2 / η1) ≦ −0.3 (2) (wherein, η1 and η2 are the shear rates 1 rad / sec and 1 at 270 ° C. of the polyester resin composition, respectively)
Shows the melt viscosity (poise) at 00 rad / sec. ) 3. A molded article comprising the polyester resin composition according to claim 1 or 2. 4. An inner coating material for a paper container, comprising the polyester resin composition according to claim 1. 5. A laminate comprising a layer made of the polyester resin composition according to claim 1 and a paper layer.