JPH11106527A - Food packaging material comprising flexible polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a packaging material excellent in flexibility, flavor retentivity, and heat sealing properties by melting and kneading a polyethylene terephthalate having a specified composition and an aliphatic polyester to effect transesterification to thereby give a flexural modulus below a specified value. SOLUTION: The polyethylene terephthalate (A) is obtained from an aromatic dicarboxylic acid containing terephthalic acid or its ester derivative and a diol containing ethylene glycol. The aliphatic polyester (B) is obtained from a 4-12C aliphatic dicarboxylic acid and a 2-13C aliphatic glycol and has a number-average molecular weight of 2,500 to 30,000. An example of the polyester B is one obtained from sebacic acid and propylene glycol. 100 pts.wt. component A is compounded with 10-100 pts.wt. component B. It is desirable that the melting and kneading temperature is usually 250-300 deg.C. The modulus in flexure of the pressed sheet is preferably at most 1,200 MPa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food packaging material, and more particularly to a food packaging material comprising a polyester resin composition having excellent flexibility and resistance to volatilization.

[0002]

TECHNICAL BACKGROUND OF THE INVENTION Retort foods, lactic acid beverages, milk, juice, alcohol, water and other food packaging materials come into direct contact with the food contents, so the innermost layer is made of fragrance. It is required to have excellent properties, gas barrier properties, oil resistance and the like. Such packaging materials include:
Polyolefins excellent in heat sealability, flexibility, pinhole resistance and the like are generally used. However, polyolefins tend to adsorb fragrance components and are accompanied by resin odor due to thermal decomposition during molding, so content that emphasizes taste and aroma, such as orange juice, coffee, water, and sake, for example. Can not be used for things.

[0003] By the way, polyethylene terephthalate is
It is attracting attention as a food packaging material because of its excellent fragrance retention, gas barrier properties, and oil resistance, but its use in packaging materials has not advanced due to its poor flexibility, heat sealability, and bending resistance. . In order to solve such a problem, various attempts have been made to impart flexibility to polyethylene terephthalate. As an example, in order to improve polyethylene terephthalate itself, a method of copolymerizing dodecanedicarboxylic acid, azelaic acid, dimer acid, or the like as a soft segment, or a polyester-polyether block copolymer having polytetramethylene glycol as a soft segment And the like. As a resin modifier, a method of blending an aromatic ester-based compound, an aromatic ether-based compound, an ethylene-vinyl acetate copolymer, an olefin elastomer, an ionomer resin, and the like has been proposed. , Fragrance retention, heat sealability, etc. are not sufficient.

Under these circumstances, the present inventors have conducted intensive studies and found that a resin obtained by melt-kneading polyethylene terephthalate and an aliphatic polyester at a specific ratio and subjecting a part or all thereof to a transesterification reaction. The composition is
The present inventors have found that they are excellent in flexibility, fragrance retention, heat sealability, and bending resistance, and have completed the present invention.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has as its object to provide a food packaging material excellent in flexibility, fragrance retention and heat sealability.

[0006]

SUMMARY OF THE INVENTION A food packaging material according to the present invention comprises (A) polyethylene terephthalate and (B) an aliphatic polyester, wherein (B) is 1 part by weight of (A) and 100 parts by weight of (A).
Melt kneading at a ratio of 0 to 100 parts by weight,
And (B) are obtained by subjecting part or all of them to a transesterification reaction, and are characterized by comprising a polyester resin composition having a flexural modulus of 1200 MPa or less.

The polyethylene terephthalate (A) includes polyethylene terephthalate obtained from an aromatic dicarboxylic acid containing terephthalic acid or its ester derivative and a diol containing ethylene glycol.

The (B) aliphatic polyester includes:
A polyester obtained from an aliphatic dicarboxylic acid having 4 to 12 carbon atoms and an aliphatic glycol having 2 to 13 carbon atoms and having a number average molecular weight in the range of 2,500 to 30,000, is preferred. , (I) a polyester obtained from sebacic acid and propylene glycol, (i)
Examples include i) a polyester obtained from adipic acid and propylene glycol, and (iii) a polyester obtained from adipic acid and ethylene glycol.

The food packaging material according to the present invention comprises a sheet and a film comprising the flexible polyester composition, a layer comprising the flexible polyester composition, and a base layer such as a metal foil or paper. Laminates, metal cans and paper packs having the flexible polyester composition coated on the inner wall thereof, trays and lids, cups and lids made of the flexible polyester composition, and the like.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the food packaging material according to the present invention will be specifically described. Food packaging material according to the present invention,
It comprises a flexible polyester composition obtained by melt-kneading (A) polyethylene terephthalate and (B) aliphatic polyester. First, each of these components will be described.

(A) Polyethylene Terephthalate (A) Polyethylene terephthalate used in the present invention is an aromatic dicarboxylic acid containing terephthalic acid or an ester derivative thereof (eg, lower alkyl ester, phenyl ester, etc.), ethylene glycol or an ester thereof. Obtained from diols containing derivatives.

(A) Polyethylene terephthalate may contain 15 mol% or less of structural units derived from an aromatic dicarboxylic acid other than terephthalic acid or an ester derivative thereof if necessary (100 mol of all structural units derived from aromatic dicarboxylic acid may be used). %). Specifically as an aromatic dicarboxylic acid other than terephthalic acid or an ester derivative thereof, isophthalic acid, phthalic acid,
Examples include naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, and the like, and ester derivatives thereof.

The polyethylene terephthalate (A) may contain 15 mol% or less of a structural unit derived from a diol other than ethylene glycol or an ester derivative thereof (if necessary, 100 mol% of all structural units derived from a diol). They may be contained in proportions. Specific examples of diols other than ethylene glycol or ester derivatives thereof include diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylene glycol (propylene glycol), butanediol,
Pentanediol, neopentyl glycol, hexamethylene glycol, dodecamethylene glycol, aliphatic glycols such as polyethylene glycol, alicyclic glycols such as cyclohexane dimethanol, bisphenols, aromatic diols such as hydroquinones,
And their ester derivatives.

Further, (A) polyethylene terephthalate may contain a small amount of a structural unit derived from a polyfunctional compound such as trimesic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, trimethylolmethane, and pentaerythritol, if necessary. , For example, 2 mol%
It may be contained in the following amount (the total of the constituent units derived from the aromatic dicarboxylic acid and the constituent units derived from the diol is 100 mol%).

The polyethylene terephthalate (A) is substantially linear, which is confirmed by the fact that the polyethylene terephthalate dissolves in o-chlorophenol.

(A) Polyethylene terephthalate has an intrinsic viscosity (IV) measured at 25 ° C. in a 1: 1 (weight ratio) mixed solvent of phenol and tetrachloroethane which is usually 0.3 to 1.5 dl /. g, preferably 0.5 to 1.2
It is desirably in the range of dl / g.

The polyethylene terephthalate (A) used in the present invention is produced from the above-mentioned aromatic dicarboxylic acid and diol by a conventionally known production method. In the present invention, as the polyethylene terephthalate (A), “raw material polyethylene terephthalate” which is usually commercially available in the form of pellets is used, but if necessary, “recovered polyethylene terephthalate” may be used. Further, "raw polyethylene terephthalate" and "recovered polyethylene terephthalate" may be mixed and used at an arbitrary ratio.

In this specification, "raw polyethylene terephthalate" refers to a molded product such as a bottle or a preform which is usually produced in the form of pellets from a dicarboxylic acid and a diol and which is passed through a molding machine in a heated and molten state. Polyethylene terephthalate which has no history of molding.
The term "recovered polyethylene terephthalate" refers to polyethylene terephthalate obtained by pelletizing polyethylene terephthalate obtained by passing such a raw material polyethylene terephthalate through a molding machine at least once in a heated and molten state. The process of “passing the raw material polyethylene terephthalate through a molding machine in a heated and melted state” is performed by heating and melting a pellet (chip) made of the raw material polyethylene terephthalate and forming it into a desired shape such as a preform or a bottle.

(B) Aliphatic Polyester The (B) aliphatic polyester used in the present invention is a polyester having no aromatic ring in its main chain, for example, an aliphatic dicarboxylic acid having 4 to 12 carbon atoms or an ester thereof. It is obtained from a derivative and an aliphatic glycol having 2 to 13 carbon atoms or an ester derivative thereof and / or an alicyclic glycol having 4 to 13 carbon atoms or an ester derivative thereof.

Examples of the aliphatic dicarboxylic acids having 4 to 12 carbon atoms and ester derivatives thereof include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, and the like. And ester derivatives of
(B) The aliphatic polyester may have, if necessary, 15 mol% or less of structural units derived from an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid or an ester derivative thereof (100 mol% of all structural units derived from dicarboxylic acid).
).

Examples of the aliphatic glycol having 2 to 13 carbon atoms include ethylene glycol, propylene glycol, trimethylene glycol, 1,2-propanediol, tetramethylene glycol, neopentyl glycol, pentamethylene glycol, hexamethylene glycol, and the like. Examples of the alicyclic glycol having 4 to 13 carbon atoms include cyclohexanediol, cyclohexane dimethylol, and 2,2-bis (4-hydroxycyclohexyl) methane.

The aliphatic polyester (B) used in the present invention includes, for example, polyethylene adipate, polyethylene sebacate, polytetramethylene dodecane, polytetramethylene azelate, polyhexamethylene azelate, poly-ε-caprolactone and the like. And an aliphatic copolyester obtained from two or more kinds of aliphatic dicarboxylic acids and one kind of glycol selected from aliphatic glycols and alicyclic glycols, one kind of aliphatic dicarboxylic acids, and aliphatic glycols and alicyclics Aliphatic polyesters obtained from two or more glycols selected from aliphatic glycols, fats obtained from two or more aliphatic dicarboxylic acids, and two or more glycols selected from aliphatic glycols and alicyclic glycols Group copolyester and the like.

As the aliphatic polyester (B) used in the present invention, at least one aliphatic dicarboxylic acid selected from adipic acid and sebacic acid and at least one aliphatic dicarboxylic acid selected from ethylene glycol, propylene glycol and tetramethylene glycol And aliphatic polyesters obtained from (i) a polyester obtained from sebacic acid and propylene glycol; (ii) a polyester obtained from adipic acid and propylene glycol; (iii) adipic acid; Polyesters obtained from ethylene glycol are preferred.

The aliphatic polyester (B) used in the present invention is produced by a conventionally known production method. (B)
The number average molecular weight of the aliphatic polyester is 2,500 to 3
It is desirably in the range of 0000, preferably 5,000 to 20,000. When the molecular weight of the (B) aliphatic polyester exceeds 30,000, the transparency of the flexible polyester resin composition may be reduced.

Flexible polyester resin composition The flexible polyester resin composition is obtained by mixing the above (A) polyethylene terephthalate and the above (B) aliphatic polyester with 100 parts by weight of the above (A).
It can be produced by melt-kneading at a ratio of from 100 to 100 parts by weight, preferably from 10 to 40 parts by weight. Melt kneading temperature is usually 250 to 300 ° C, preferably 270 ° C.
290 ° C.

The melt-kneading may be carried out by any known method, but it is a polymerization apparatus equipped with a double spiral type stirring blade capable of stirring under reduced pressure. A method of melt-kneading while depressurizing and distilling out of the system, a method of melt-kneading using a single-screw or twin-screw extruder, and the like can be adopted. When melt kneading is performed using an extruder, a flexible polyester resin composition can be manufactured with higher productivity.

When (A) polyethylene terephthalate and (B) an aliphatic polyester are melt-kneaded, a transesterification reaction occurs in part or all of the above-mentioned components, and as a result, a soft polyester resin composition having excellent flexibility and volatility resistance Is obtained.

The flexible polyester resin composition according to the present invention has a bending elastic modulus of a press sheet of 1200 MPa or less, preferably 50 to 11 as measured by a method described later.
00 MPa, more preferably in the range of 100 to 260 MPa. Simply melt-kneading (A) polyethylene terephthalate and (B) aliphatic polyester does not provide a composition having the above-described elastic modulus,
When a transesterification reaction occurs in part or all of (A) and (B), a composition having the above-described elastic modulus can be obtained.

In producing the flexible polyester resin composition, a catalyst generally used in producing polyester may be used. This catalyst includes lithium, sodium, potassium, cesium, magnesium,
Metals such as calcium, barium, strontium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, cadmium, manganese, and the like, and their organometallic compounds, organic acid salts, metal alkoxides,
And metal oxides. Particularly preferred catalysts are calcium acetate, dibutyltin oxide, tetrabutyl titanate, germanium dioxide, and antimony trioxide. These catalysts can be used alone or in combination of two or more.

Further, in order to improve the thermal stability during melt kneading,
Various stabilizers such as hindered phenolic antioxidants and phosphorus stabilizers may be used. The addition amount of these stabilizers is preferably 0.05 to 5% by weight.

Examples of the hindered phenol-based antioxidant include triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] and 1,6-hexanediol-bis [3 -(3,5-dibutyl-
4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris- (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 3,5-t-butyl- 4-hydroxy-benzylphosphonate-diethyl ester, tris- (3,
5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 2,6-di-t-butyl-4-methylphenol, 1,1,3-tris (2-methyl-4-hydroxy-5- t-butylphenyl) butane, N, N'-hexamethylenebis (3,5-di-t-butyl-4-
Hydroxy-hydrocinnamamide), octadecyl-3-
(3,5-di-t-butyl-4-hydroxyphenyl) propionate, tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane and the like.

Examples of the phosphorus-based stabilizer include tris (nonylphenyl) phosphite, triisooctyl phosphite, triisodecyl phosphite, triphenyl phosphite, diphenyl isodecyl phosphite,
Phosphite compounds such as phenylisodecyl phosphite, diisooctyl phenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, distearyl pentaerythritol-di-phosphite, dioctyl pentaerythritol-di- Phosphite, diisodecylpentaerythritol-di-phosphite, bis (2,4-
And pentaerythritol-di-phosphite compounds such as (di-t-butylphenyl) pentaerythritol.

[0033] Such a flexible polyester resin composition is tasteless and odorless, and has good fragrance retention due to little adsorption and permeation of flavor components. In addition, it has excellent heat sealability and flexibility, and when coated on another substrate, has excellent pinhole resistance and bending resistance as well as good adhesiveness.

Food packaging materials Food packaging materials using the flexible polyester resin composition include films, sheets, trays and their lids, cups and their lids, and bag-in-boxes. Further, as a food packaging material comprising the flexible polyester resin composition and other materials, a layer composed of the flexible polyester resin composition and a metal foil, paper, polyethylene, polypropylene, a base layer such as nylon. (Film, sheet), a retort pack comprising the laminate, a paper pack having an inner wall coated with a flexible polyester resin composition, a metal can, and the like. When the food packaging material is a laminate, the inside (the side that comes into contact with the food) is a layer made of the flexible polyester resin composition.

The thickness of the film is usually 5 to 150 μm.
m, and the thickness of the sheet is usually 150 to 300 μm. The film or sheet can be molded by a known molding method, for example, by a molding method such as inflation molding, T-die molding, or calendar molding.

The flexible polyester resin composition which is a coat layer of a paper pack, a metal can, or the like, is prepared such that the amount of the aliphatic polyester (B) in preparing the composition is based on 100 parts by weight of (A) polyethylene terephthalate. , Usually 25-50
It is a proportion of 30 parts by weight, preferably 30 to 40 parts by weight, and the flexural modulus of the composition is usually 260 to 50 MPa, preferably 200 to 100 MPa.

In the flexible polyester composition constituting the laminate, the amount of (B) the aliphatic polyester used in preparing the composition is usually 20 to 40 parts by weight based on 100 parts by weight of (A) polyethylene terephthalate. , Preferably 25 to
35 parts by weight, and the composition has a flexural modulus of usually 11
00 to 100 MPa, preferably 260 to 140 MPa
It is.

The flexible polyester composition forming the tray and its lid, the cup and its lid and the like is prepared by adding (A) 100 parts by weight of polyethylene terephthalate (B) when preparing the composition. To 20 parts by weight, preferably 25 to 30 parts by weight, and the flexural modulus of the composition is usually 1100 to 100 parts by weight.
It is 140 MPa, preferably 260 to 200 MPa.

In the food packaging material according to the present invention, when the opening is heat-sealed and sealed, no plastic odor is generated from the heat bonding layer and there is no fear of impairing the flavor of the food. It is suitable for packaging such as sake. In addition, since the flexible polyester resin composition basically does not contain chlorine, the molded packaging material does not generate hydrogen chloride at the time of incineration, and thus does not cause an environmental pollution problem.

[0040]

The food packaging material according to the present invention is excellent in flexibility, heat sealability and fragrance retention. Further, since the polyester resin composition forming the food packaging material of the present invention does not contain chlorine, it does not generate hydrogen chloride during incineration.

[0041]

EXAMPLES Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

In the present specification, measurement of various physical properties and preparation of a sheet are performed as follows. (1) Intrinsic viscosity (IV) 1: 1 (weight ratio) of phenol and tetrachloroethane
A 0.5 g / dl sample solution was prepared using a mixed solvent,
It was calculated from the solution viscosity measured at 25 ° C. (2) Melting point (Tm) It was determined using a differential scanning calorimeter (manufactured by Seiko Instruments Inc.). The dried sample was dried at 270 ° C under a nitrogen stream for 5 minutes.
For 1 minute, and then using liquid nitrogen at 100 ° C. /
The temperature was rapidly cooled to -150 ° C. at a temperature lowering rate of 10 minutes, and held for 10 minutes. This sample was heated to 280 ° C. at a rate of 10 ° C./min to determine the melting point. (3) Forming method of press sheet The dried sample is pressed with a press forming machine at a forming temperature of 280 ° C.
A quenched press sheet was prepared by heating and melting in a spacer shape of 100 mm × 100 mm × 1.5 mm, immediately transferred to a press forming machine at 0 ° C., and press-formed.
This press sheet was subjected to measurement of flexural modulus, tensile strength, and elongation at break. (4) Flexural modulus test A strip-shaped test piece of 1.27 cm in width and 6.35 cm in length produced by cutting from a press sheet was crossheaded at 23 ° C. using a tensile tester model 4501 manufactured by Instron. The test was performed at a speed of 5 mm / min. (5) Tensile Strength and Elongation Using an Instron Digital Control Universal Material Testing Machine Model 4501, the test piece shape was measured according to JIS-K7113-2, a tensile speed of 30 mm / min, and a room temperature of 23 ° C. (6) Number average molecular weight The number average molecular weight (in terms of polystyrene) by gel permeation chromatography (GPC) analysis measured under the following conditions was used.

Column: PLgel 5μMIXD-C
7.5 × 300 mm 2 tubes (manufactured by Polymer Laboratory) Mobile phase: chloroform (for high performance liquid chromatography, manufactured by Kanto Chemical) Flow rate: 1.0 ml / min Sample concentration: 0.5% chloroform solution, (7) transparency (Haze value) The dried sample was pressed with a press molding machine at a molding temperature of 280 ° C.
Measure the haze value (irregular reflectance of white light) of the quenched press sheet obtained by heating and melting in a spacer shape of 100 mm x 100 mm x 0.5 mm, immediately transferring to a 0 ° C press forming machine and pressing. Then, the transparency was evaluated. (8) Adsorption test of d-limonene The dried sample was heated and melted in a molding machine at a molding temperature of 280 ° C. with a spacer shape of 30 mm × 30 mm × 0.5 mm, and immediately transferred to a press molding machine at 0 ° C. for pressure molding. Thus, a quenched press sheet was formed. After measuring the weight of this press sheet, it is immersed in a 100% solution of d-limonene, which is an aroma component, stored in a constant temperature room at 23 ° C., taken out after a predetermined time, wiped the surface with a cotton cloth, and immediately measured the weight. did. From the weight change of the press sheet before and after d-limonene immersion, the amount of d-limonene adsorbed on the press sheet was calculated and expressed as a percentage by weight. (9) Heat seal strength test The dried sample was molded at a molding temperature of 280 ° C by a press molding machine.
Was heated and melted in a 140 mm × 140 mm × 0.1 mm spacer shape, and immediately transferred to a press forming machine at 0 ° C. and pressure-formed to form a quenched press sheet. This press sheet was heated at a temperature of 23 ° C and a relative humidity of 50%.
After leaving for 1 week in the room, cut out to 20mm width
Sandwiched between two pieces of 0 μm soft aluminum, and further sandwiched between 100 μm Teflon sheets from both sides, with a bar sealer at a temperature of 170 ° C., 190 ° C., 220 ° C.
At 0 ° C., heat sealing was performed under the conditions of a pressure of 0.2 MPa and 5 seconds. Next, the heat-sealed portion was cut into a strip shape so as to have a width of 15 mm, thereby obtaining a T-type peel strength measurement sample. Measurement of T-peel strength was performed at a temperature of 23 ° C. and a relative humidity of 5
The measurement was performed under a 0% indoor environment under the conditions of a distance between chucks of 50 mm and a tensile speed of 100 mm / min.

In Examples and Comparative Examples, the following were used as polyethylene terephthalate, aliphatic polyester, plasticizer and the like. (A-1) It is obtained from polyethylene terephthalate terephthalic acid and ethylene glycol, and has an intrinsic viscosity (IV) of 0.79 in a 1: 1 (weight ratio) mixed solvent of phenol and tetrachloroethane at 25 ° C.
dl / g polyethylene terephthalate.

(B-1) 10 with a cooling pipe for removing distillate due to aliphatic polyester reaction
In a 00 ml four-necked kolben, add dimethyl adipate 34
8.0 g, 365.0 g of propylene glycol and 0.245 g of manganese acetate (0.05 mol% based on the acid)
While stirring under a stream of nitrogen, to 8
The esterification reaction was carried out by raising the temperature over time, and the reaction rate was 97
% Of the esterification reaction was obtained. 500 g of the obtained esterification reaction product, 0.240 g of antimony acetate (0.042 mol% based on the acid) and 2.5 g of Irganox 1010 ^™ (manufactured by Ciba Geigy) were placed in a polymerization vessel equipped with a double spiral type stirring blade. After replacing with nitrogen, the number of rotations was 4.2 s ^-1 under reduced pressure.
The temperature was raised to 235 ° C. over 3.5 hours while stirring at
Further, while maintaining 235 ° C., the mixture was maintained for 4 hours while distilling off propylene glycol by-produced under a reduced pressure of 133.3 Pa, and the number average molecular weight obtained by condensation polymerization was 5,030.
Aliphatic polyester.

(B-2) 10 with a cooling pipe for removing distillate due to aliphatic polyester reaction
Add dimethyl adipate 450.
0 g, ethylene glycol 384.8 g and manganese acetate 0.317 g (0.05 mol% based on acid) were charged, and the mixture was heated to 220 ° C. over 8 hours while stirring under a nitrogen stream to carry out an esterification reaction. An esterification reaction product having a conversion of 95.4% was obtained. Obtained esterification reaction product 5
50 g, 0.052 g of germanium dioxide (0.021 mol% based on the acid) and 2.75 g of Irganox 1010 ^™ (manufactured by Ciba Geigy) were placed in a polymerization vessel equipped with a double helix-type stirring blade, and after purging with nitrogen, the pressure was reduced. 4.2s rotation speed below
^The temperature was raised to 235 ° C. over 3.5 hours while stirring at ⁻¹ , and further maintained at 235 ° C. under reduced pressure of 133.3 Pa for 4 hours while distilling off by-produced ethylene glycol to reduce the temperature. The number average molecular weight obtained by polymerization is 5,57.
0 aliphatic polyester.

Polysizer P-202 ^TM (Dainippon Ink Chemicals)
An aliphatic polyester having a number average molecular weight of 18,600 and obtained from sebacic acid and propylene glycol.

Polysizer W-4000 ^™ (Dainippon Ink Chemicals)
Industry Co., Ltd.) having a viscosity of 15,000~30,000mPa · s,
Adipic acid-based polyester plasticizer.

[0049]

Example 1 (A-1) Polyethylene terephthalate 26
8g, Polysizer P-202^TM132g, Irganox
1010^TM2.0 g (manufactured by Ciba-Geigy) and gel dioxide
0.043 g of manium is mixed with 500 ml of a double helix type
Place in a polymerization vessel with stirring blades, purge with nitrogen, and then to 180 ° C
The temperature was raised and maintained under a reduced pressure of 13.3 Pa for 3 hours. Next
The temperature was raised to 280 ° C. over 1 hour, and the pressure was increased to 39.9 Pa.
Under reduced pressure, rotational speed 4.2s ^-1While stirring for 2 hours
Exchange reaction was performed. Obtained polyester resin composition
Had an intrinsic viscosity (IV) of 0.56 dl / g.

Next, after sufficiently drying the polyester resin composition, a sheet having a thickness of 0.5 mm was formed by the press sheet forming method described above. The obtained sheet has a flexural modulus of 56.
It was a slightly opaque sheet which was MPa and had a flexible touch and was very flexible. The results of measuring various physical properties of this sheet are shown in Tables 1 to 3.

[0051]

EXAMPLE 2 The amount of (A-1) Polyethylene terephthalate 300 g, except that the amount of Polycizer P-202 ^TM was 100g were to transesterification reaction in the same manner as in Example 1. The intrinsic viscosity (IV) of the obtained polyester resin composition was 0.53 dl / g.

Next, the polyester resin composition was sufficiently dried, and a sheet having a thickness of 0.5 mm was formed by the press sheet forming method described above. The obtained sheet has a flexural modulus of 16
It was 1 MPa and was a transparent and flexible sheet.
Various physical properties of this sheet were measured. Table 1 shows the results.
3 is shown.

[0053]

Example 3 (A-1) Polyethylene terephthalate 26
8 g, 132 g of (B-1) aliphatic polyester, 2.0 g of Irganox 1010 ^™ (manufactured by Ciba Geigy) and 0.043 g of germanium dioxide were placed in a 500 ml polymerization vessel equipped with a double helix-type stirring blade, followed by purging with nitrogen. 180 ° C
And kept under reduced pressure of 1.3 Pa for 3 hours. Then, the temperature was raised to 280 ° C. over 1 hour, and transesterification was carried out under a reduced pressure of 13.3 Pa with stirring at a rotation speed of 4.2 s ⁻¹ for 2 hours. The intrinsic viscosity (IV) of the obtained polyester resin composition was 0.58 dl / g.

Next, after sufficiently drying the polyester resin composition, a 0.5 mm thick sheet was formed by the press sheet forming method described above. The obtained sheet has a flexural modulus of 61.
It was a flexible, soft, transparent sheet with a soft feel. Various physical properties of this sheet were measured. The results are shown in Tables 1 to 3.

[0055]

Example 4 Instead of the Polycizer ^{P-202 TM, (B-} 2)
A transesterification reaction was performed in the same manner as in Example 1 except that an aliphatic polyester was used. The intrinsic viscosity (IV) of the obtained polyester resin composition was 0.57 dl / g.

Next, after sufficiently drying the polyester resin composition, a sheet having a thickness of 0.5 mm was formed by the press sheet forming method described above. The obtained sheet has a flexural modulus of 68.
MPa, supple touch, transparent and flexible. The results of measuring various physical properties of this sheet are shown in Tables 1 to 3.

[0057]

Comparative Example 1 (A-1) After sufficiently drying polyethylene terephthalate, a thickness of 0.5 m was obtained by the press sheet molding method described above.
m were formed. Various physical properties of the obtained sheet were measured. Table 1 shows the results.

[0058]

Comparative Example 2 A transesterification reaction was carried out in the same manner as in Example 1 except that Polysizer W-4000 ^™ was used instead of Polysizer P-202 ^™ . The intrinsic viscosity (IV) of the obtained polyester resin composition was 0.36 dl / g. The press sheet molded product of this polyester resin composition was very brittle, and a test piece could not be prepared. Table 1 shows the crystal melting temperatures.

[0059]

Comparative Example 3 (A-1) Polyethylene terephthalate 26
8 g, dioctyl phthalate (reagent first grade, manufactured by Wako Pure Chemical Industries, Ltd.) 132 g, Irganox 1010 ^™ (manufactured by Ciba Geigy) 2.0 g, and germanium dioxide 0.043
g was placed in a 500 ml polymerization vessel equipped with a double helix stirring blade, and after purging with nitrogen, the temperature was raised to 280 ° C. over 1 hour, and the mixture was stirred at a rotation speed of 4.2 s ⁻¹ for 2 hours.
The transesterification reaction was performed while maintaining the pressure at 9 Pa for 1 hour. The intrinsic viscosity (I) of the obtained polyester resin composition
V) was 0.32 dl / g. The press sheet molded product of this polyester resin composition was very brittle, and a test piece could not be prepared. Table 1 shows the crystal melting temperatures.

[0060]

Comparative Example 4 MFR: 3.7 g / 10 min, density: 0.92
Using low-density polyethylene having ³ g / cm ³ and an endothermic peak temperature of 110 ° C., at a molding temperature of 160 ° C. and 30 mm ×
A quenched press sheet having a shape of 30 mm × 0.5 mm was formed, and after measuring the weight, the d-limonene adsorption test was evaluated. Table 2 shows the results. At a molding temperature of 180 ° C., 14
A quenched press sheet having a shape of 0 mm × 140 mm × 0.1 mm was formed, and the heat seal strength was evaluated. The results are shown in Table 3.

[0061]

Comparative Example 5 Block copolymer of polybutylene terephthalate and polyether [Hytrel 5526 ^™ , manufactured by Du Pont-Toray Co., Ltd., intrinsic viscosity (IV): 1.433 dl /
g] was sufficiently dried, and then a sheet having a thickness of 0.5 mm was formed by the press sheet forming method described above. The obtained sheet had a flexural modulus of 147 MPa and was a flexible opaque sheet. Tables 1 and 3 show the results of measuring various physical properties of the copolymer and the sheet.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

[Table 3]

Claims (15)

[Claims] (A) polyethylene terephthalate,
(B) An aliphatic polyester is melt-kneaded at a ratio of 10 to 100 parts by weight of (B) with respect to 100 parts by weight of (A), and a part or all of (A) and (B) is mixed. Are subjected to a transesterification reaction and have a flexural modulus of 12
A food packaging material comprising a polyester resin composition having a pressure of 00 MPa or less. 2. The food packaging material according to claim 1, wherein (A) the polyethylene terephthalate is obtained from an aromatic dicarboxylic acid containing terephthalic acid or an ester derivative thereof and a diol containing ethylene glycol. 3. The aliphatic polyester (B) is obtained from an aliphatic having 4 to 12 carbon atoms and an aliphatic glycol having 2 to 13 carbon atoms, and having a number average molecular weight of 2,500.
The food packaging material according to claim 1 or 2, wherein the food packaging material is in the range of ~ 30,000. 4. The food packaging material according to claim 3, wherein (B) the aliphatic polyester is at least one selected from the following (i) to (iii): (i) sebacic acid, propylene glycol and (Ii) Polyester obtained from adipic acid and propylene glycol (iii) Polyester obtained from adipic acid and ethylene glycol 5. A sheet for food packaging, comprising the flexible polyester composition according to claim 1. 6. A film for food packaging, comprising the flexible polyester composition according to any one of claims 1 to 4. 7. A laminate for food packaging, comprising a laminate of a layer comprising the flexible polyester composition according to claim 1 and a base material layer. 8. The laminate for food packaging according to claim 7, wherein the layer comprising the flexible polyester composition is a heat seal layer. 9. The food packaging laminate according to claim 7, wherein the substrate is a metal foil. 10. A metal can comprising a flexible polyester composition according to claim 1 coated on an inner wall. 11. A paper pack comprising an inner wall coated with the flexible polyester composition according to claim 1. 12. A tray comprising the flexible polyester composition according to claim 1. 13. A tray lid comprising the flexible polyester composition according to claim 1. Description: 14. A cup comprising the flexible polyester composition according to claim 1. Description: 15. A lid for a cup, comprising the flexible polyester composition according to claim 1. Description: