JPH02150419A - Polyester having excellent gas barrier property - Google Patents

Abstract

PURPOSE:To obtain the title polyester having excellent heat resistance and gas barrier properties by using phthalic naphthylenedicarboxylic acid or an ester forming derivative thereof as a dicarboxylic acid component and a component having a specific repeating unit as a glycol component. CONSTITUTION:The aimed polyester consisting of repeating units shown by formula I and formula II (R is group shown by formula III, group shown by formula IV or mixture thereof; m is 2-10), comprising 0-95mol% group shown by formula I and 100-5mol% group shown by formula Il. Preferably >=80mol% group shown by formula I is expressed by unit shown by formula V and >=80mol% group shown by formula II is expressed by unit shown by formula VI. The polyester has preferably >=70 deg.C glass transition temperature and 0.3-1.5 intrinsic viscosity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyester having excellent gas barrier properties.

[Conventional technology]

Due to its excellent mechanical and chemical properties, polyethylene terephthalate (hereinafter referred to as PET) is processed into various containers such as films, sheets, bottles, cups, and trays, and is widely used as a packaging material.

However, although PET is superior to polyethylene and polypropylene in terms of gas barrier properties against oxygen and carbon oxide, it is still not sufficient, and there is a demand for improved performance of the sealing layer in many applications.

For example, in containers with pressurized interiors such as carbonated beverages, the gas barrier performance of the conventionally known level is insufficient, and it is not possible to prevent the carbon dioxide gas in the container from gradually dissipating. When oxygen is present inside food packaging, there are problems such as the contents being oxidized by ultraviolet rays during storage and deterioration in quality. This has been an extremely serious problem in the past, especially for foods containing oil and fat components, but with the recent expansion of natural foods and health foods, the number of ``additive-free'' and ``low-sodium'' products has increased. Demand for gas barrier properties is also becoming stronger for general food packaging materials.

A method for improving the gas barrier properties of PET as a packaging material is to use a resin that has better gas barrier properties than PET1.
For example, methods are known in which polyvinylidene chloride, saponified ethylene-vinyl acetate copolymer, polyamide, etc. are coated or laminated, but all of these resins have poor adhesion to PET and cause delamination in one layer. Not only does this result in loss of transparency of the container, but it is also disadvantageous in terms of recovery.

On the other hand, JP-A-59-64624 discloses a method using a polymer in which part or all of the terephthalic acid component of PET is replaced with isophthalic acid instead of PET.

Polymer Engine, Set, 22 (14
L 857 (1982) and others. However, satisfactory barrier properties have not been achieved even by methods using polyethylene isophthalate or copolymers thereof.

Also, as a method for improving the gas barrier properties of PET, a method of copolymerizing PET with isophthalic acid and 1,3-bis(β-hydroxyethoxy)benzene was published in JP-A No. 5
8-167617, or a fly. A method for copolymerizing 3-phenylenedioxydiacetic acid into PET was published in 1986.
It has been proposed in Publication No. 0-501060 and the like. However, such copolymerized polyesters have extremely low glass transition temperatures, have completely insufficient heat resistance, and cannot be said to be practical.

On the other hand, a method of laminating polyethylene naphthalate polyester on PET is disclosed in JP-A-61-279553, and a method of blending a condensed liquid crystal polymer with polyethylene naphthalate is disclosed in JP-A-62-119.
Although it has been proposed in Japanese Patent No. 265, satisfactory gas barrier performance has not been obtained in any of them.

[Problem to be solved by the invention]

In view of this situation, in which a polyester with high gas barrier properties has not yet been found,5 the present inventors have worked diligently to provide a polyester with excellent gas barrier properties that cannot be achieved with conventional polyesters. As a result of investigation, we have reached a non-invention.0 [Means for solving the problem] The mineral of the present invention is composed of repeating units represented by the following general formulas [1] and (n), where (1) is 0 to 95 mol. The present invention provides a polyester characterized in that [■] is 100 to 5 mol.

The present invention will be specifically explained below.

The polyester of the present invention contains naphthylene dicarboxylic acid or its ester-forming derivative and naphthylene dioxydiacetic acid or its ester-forming derivative as the dicarboxylic acid component, and m in the above general formulas [1] and [■] as the glycol component. The constituent component is a linear aliphatic glycol that is an integer of ~10.

Among the dicarboxylic acid components, naphthylene dicarboxylic acid or its ester-forming derivative is 0 to 95 mol, and naphthylene dioxydiacetic acid or its ester-forming derivative is 100 to 5 mol. In consideration of consideration 1, it is preferable that the former is 20 to 95 mol, and the latter is 5 to 80 mol. If the amount of naphthylenedioxydiacetic acid or its ester-forming derivative is less than 5 molt, the gas barrier performance of the molded article obtained from the resulting polyester will not be substantially improved.

As the naphthylene dicarboxylic acid or its ester-forming derivative, 2,6-naphthylene dicarboxylic rR
11,4-naphthylene dicarboxylic acid or a mixture thereof is preferred, and 2,6-naphthylene dicarboxylic acid accounts for 80 or more moles of the heat resistance, gas barrier properties, moldability, etc. of the molded product obtained from the resulting polyester. It is particularly preferable. In addition, as 2,6-dioxydiacetic acid or its ester-forming derivative,
-Naphthylene dioxydiacetic acid, 1,4-naphthylene dioxydiacetic acid, or a mixture thereof is preferred, and 80 or more moles of these are preferred in terms of heat resistance, gas barrier properties, moldability, etc. of the molded product obtained from the resulting polyester.
．． Particularly preferred is 6-naphthylene oxydiacetic acid or an ester-forming derivative thereof.

In the polyester of the present invention, dicarboxylic acid components other than naphthylene dicarboxylic acid, naphthylene dioxydiacetic acid, or their ester-forming derivatives are used in an amount of 10 mole or less, such as aliphatic acids such as cono-phosphoric acid, adipic acid, and sebacic acid. dicarboxylic acid or its ester-forming derivative, terephthalic acid, isophthalic acid, 4,4-diphenyldicarboxylic acid, 1,2-bis(2-chlorophenoxy)ethane-4,4-dicarboxylic acid, phenylenedioxydiacetic acid, Aromatic dicarboxylic acids or their ester-forming derivatives such as bis(4-carboxymethoxyphenyl)sulfone, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid or their ester-forming derivatives, hydroxy 7
Benzoic acid, hydroquinaphthoic acid, hydroxyacetic acid, 3
- Oxycarboxylic acids such as hydroxypropionic acid or ester-forming derivatives thereof can be used as copolymerization components. As the ester-forming derivatives of the above dicarboxylic acids or oxycarboxylic acids, esters with lower alcohols such as methanol and ethanol are generally used, but esters with glycols such as ethylene glycol may also be used. .

In the polyester of the present invention, the glycol component is a linear aliphatic glycol in which m is an integer of 2 to 10 in the general formulas [1] and [■], such as ethylene glycol, tetramethylene glycol, hexamethylene glycol, and octamethylene glycol. Examples include glycol, but preferably m is 2? Glycols where m is an integer of -4 are preferred, especially ethylene glycol where m is 2. Other glycol components, such as aliphatic glycols such as neopentyl glycol, alicyclic glycols such as 1,4-cyclohexane dimetatool, and 1,3-bis(β-hydroxyethoxy) at a ratio of 10 molar or less, may be used. Aromatic glycols such as benzene, bis(β-hydroxyethoxy)bisphenol S, and polymeric glycols such as polyethylene glycol and polypropylene glycol can be used as copolymerization components.

Further, the polyester of the present invention includes, for example, glycerin,
Trimethyl or higher polyfunctional compounds such as trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid, etc. may be copolymerized to the extent that melt molding is possible.

The polyester of the present invention can be produced by a method established for producing conventional polyethylene terephthalate. For example, it can be obtained by a method in which a dicarboxylic acid and a glycol are subjected to an esterification reaction followed by a polycondensation reaction, or a dicarboxylic acid ester and a glycol are subjected to a transesterification reaction and then subjected to a polycondensation reaction. Furthermore, among the dicarboxylic acid components, naphthylenedioxydiacetic acid or its ester-forming derivative can be added after the esterification reaction or the transesterification reaction.

In this case, it is preferable to use an esterification catalyst, a transesterification catalyst, a polycondensation catalyst, a stabilizer, etc., but these catalysts,
As stabilizers, etc., those known as polyester catalysts, especially polyethylene terephthalate catalysts, stabilizers, etc. can be used. For example, catalysts that promote these reactions include sodium, magnesium, calcium, zinc, manganese, Examples of the stabilizer include metal compounds such as tin, tungsten, germanium, titanium, and antimony, and phosphorus compounds such as phosphoric acid, υ/acid esters, phosphorous acid, and phosphite esters. Furthermore, other additives (colorants, ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, etc.), fillers (silica,
wollastonite, talc, calcium carbonate, mica, etc.), reinforcing agents (glass fiber, etc.) can also be added.
The polyester of the present invention obtained by the above method is
Intrinsic viscosity is 0.3 to 1.5, preferably 0.4 to 1.2
The glass transition temperature is preferably 70° C. or higher, preferably 80° C. or higher in terms of moldability and resistance to 3.

The polyester of the present invention can be melt molded and can be molded into sheets, films, or hollow containers by known molding methods such as injection molding, blow molding, biaxial stretch blow molding, vacuum molding, compression molding, etc. . The sheet or film can be formed into packaging materials such as wraps, bags, etc.

In addition, the polyester of the present invention can be used with other polymers such as polyolefin resins such as polyethylene and polypropylene,
It can also be laminated with polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyamide resins such as nylon, and can be made into film-like, sheet-like, and tube-like laminates by coextrusion, dry lamination, sandwich lamination, etc. You can also do that.

The molded article obtained from the polyester of the present invention has, for example, an oxygen permeability coefficient of about 1 to 60 that of polyethylene terephthalate.
%, about 2 to 80 of polyethylene-2,6-naphthalate
Since it is small in size and has excellent gas barrier performance, it is useful as a packaging material in cases where improved gas barrier properties are required. [Example] The present invention will be specifically explained below with reference to Examples.

It should be noted that the portion in the examples means a heavily shot portion.

The physical property values of this example were measured according to the following method.

1) Intrinsic viscosity ([η]) Measured at 30°C at a concentration of 10 μ using an equiweight mixed solvent of phenol/tetrachloroethane. 2) Glass transition temperature (Tg) Differential scanning calorimeter (manufactured by Mettler, TA- 3000 model) to the sample in the quenched amorphous state. , measured at a heating rate of 10° C./min.

3) Oxygen permeability (Po2) After drying the polymer at about 50°C under reduced pressure for at least 20 hours, it was extruded using an extruder (Labo Blast Mill, manufactured by Toyo Seiki Seisakusho) at a temperature of 280°C, and immediately put on a chill roll ( The film was rapidly cooled using a roll surface temperature of 30° C.) to obtain a non-oriented film with a thickness of 75Afn. The film was measured in a dry state at 35° C. (0° R1H0) using a gas permeability measuring device (Yanagimoto Seisakusho Rip, GTRIO type).

The unit is cc-20liV'd-day-atm.

Example 1 2.6-naphthalene dicarboxylic acid dimethyl ester 10
000 parts (95 molty), 718 parts (5 mol%) of diethyl 2,6-naphthylene cyclooxydiacetate, 6019 parts of ethylene glycol (molar ratio of ethylene glycol to dicarboxylic acid component is 2.25:1), and Charge 2.6 parts of manganese acetate tetrahydrate into a reactor and heat to 190°C with stirring.
After gradually increasing the temperature to ~240°C over about 3 hours and distilling off more than 99% of the theoretical amount of methanol and ethanol, 0.9 parts of phosphorous acid and 4.2 parts of germanium dioxide were added, and the mixture was heated to 290°C. Polycondensation was carried out at a temperature of 0.5 vs. 1 g or less under high vacuum for about 2 hours. Table 1 shows the values of the intrinsic viscosity [η], glass transition temperature Tgs, and oxygen permeation amount PO2 of the obtained polymer.

Example 2 A copolymerized polyester was obtained in the same manner as in Example 1, except that the amount of modification with 2,6-naphthylenethioxydiacetic acid was changed from 5 molty to 10 molty. Table 1 shows the measured physical property values.

Example 3 A copolymerized polyester was produced in the same manner as in Example 1, except that the amount of modification with 2,6-naphthylenethioxydiacetic acid was changed from 5 mol to more than 20 mol. Table 1 shows the measured physical property values.

Example 4 A copolymerized polyester was obtained in the same manner as in Example 1, except that the amount of modification with 2,6-naphthylenethioxydiacetic acid was changed from 5 molti to 50 molti. Table 1 shows the measured physical property values.

Example 5 The same procedure as in Example 1 was carried out except that the amount of modification with 2,6-su-7 ethylenedioxydiacetic acid in Example 1 was changed from 5 molti to 100 molti, that is, all the dicarboxylic acid components were changed to 2,6-su-7 ethylenedioxydiacetic acid. Polyethylene-2
, 6-naphthylenedioxydiacetate was obtained. The measured physical property values are shown in Table 1. Example 6 The same procedure as in Example 2 was carried out except that 1,4-7-ethylenedioxydiacetic acid was used instead of 2,6-naphthylenedioxydiacetic acid. A polymerized polyester was obtained. Table 1 shows the measured physical property values.

Example 7 A copolymerized polyester was obtained in the same manner as in Example 3 except that 1,4-naphthylenedioxydiacetic acid was used instead of 2,6-naphthylenedioxydiacetic acid. Table 1 shows the measured physical property values.

Comparative Example 1 In Example 1, the amount of modification by 2,6-naphthylene cyclooxydiacetic acid was changed from t-5 mol to 0 mol, that is, all the dicarboxylic acid components were changed to 2,6-s7tale dicarboxylic acid, and the final polymerization temperature was changed to 290 mol. Polyethylene-2,6-7thalene dicarpoxylate was prepared in the same manner as in Example 1 except that the temperature was changed from 300°C to 300°C. Table 1 shows the measured physical property values.
Shown below.

Comparative Example 2 Polyethylene terephthalate was obtained in the same manner as in Example 1 except that all the dicarboxylic acid components were replaced with terephthalic acid. Table 1 shows the measured physical property values.

Table 1 [Effects of the Invention] The molded product obtained from the polyester of the present invention maintains heat resistance comparable to that of polyethylene terephthalate, has excellent gas barrier properties against oxygen, etc., and requires improved gas rapid rupture properties. M-ho is used as a packaging material.

Patent applicant: Legal company Representative Patent Attorney Ken Honda

Claims (8)

[Claims] (1) It is composed of repeating units represented by the following general formulas [I] and [II], and ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...・[II] (In the formula, R indicates ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, or a mixture thereof, and m is an integer from 2 to 10.) I] is 0 to 95 mol%, [II] is 100 to 5 mol%
A polyester characterized by: (2) Of the general formula [I], 80 mol% or more ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, m is an integer from 2 to 10.) The polyester according to claim 1, characterized in that it is. (3) Claim 1 characterized in that 80 mol% or more of the general formula [II] is ▲A mathematical formula, a chemical formula, a table, etc.▼ (where m is an integer from 2 to 10) Or the polyester described in 2. (4) In general formulas [I] and [II], m is 2 to 4
The polyester according to any one of claims 1 to 3, which is an integer of . (5) Claims 1 to 3 having a glass transition temperature of 70°C or higher
4. The polyester according to any one of 4. (6) The polyester according to any one of claims 1 to 4, which has an intrinsic viscosity of 0.3 to 1.5. (7) A film or sheet made of the polyester according to any one of claims 1 to 4. (8) A molded container made of the polyester according to any one of claims 1 to 4.