JPH107776A - Copolyester resin and multilayered molded article made by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copolyester resin excellent in gas-barrier properties, transparency, and UV-screening properties and a multilayered molded article made by using the same. SOLUTION: The resin, which has an excellent compatibility with a polyethylene terephthalate resin, comprises 50-92mol% ethylene isophthalate units, 5-47mol% ethylene terephthalate units, and 3-45mol% ethylene 2,6-naphthalate units. It has an oxygen permeability constant of 3.0cc.mm/m<2> .day.atm or smaller and a light transmittance of 85% or higher, and absorbs ultraviolet having wavelengths of 340nm and smaller. The molded article is made by using the resin as an intermediate layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a polyester copolymer resin suitable for a molded article for packaging requiring characteristics such as gas barrier properties, transparency and UV cut properties, and a multilayer using the polyester copolymer resin of the present invention. Related to molded products. More specifically, examples of the multilayer molded product include blow molded products such as stretch blow and direct blow, and extruded products such as films and sheets.

[0002]

2. Description of the Related Art Conventionally, polyethylene terephthalate resin (hereinafter referred to as PET) has been widely used as a packaging material and a container, for example, a stretch blow-molded product because of its excellent properties of mechanical strength, transparency and gas barrier property. It is used. Further, vinyl chloride resin (hereinafter referred to as PVC) is also used as various packaging materials and containers because of its excellent gas barrier properties.

However, such PET molded products, PV
Even in the case of molded C products, the gas barrier properties of oxygen and the like are not sufficient, and when stored for a long period of time, or when high gas barrier properties are required, such as when the container is small, there is a disadvantage that the commercial value of the contents is lowered. . In addition, it is essential that the packaging material and the container are transparent from the appearance, and prevention of deterioration and discoloration of the contents due to ultraviolet rays is also required. Further, in recent years, generation of harmful gas at the time of extinction of a molded article using a PVC resin has been greatly noticed particularly due to the problem of environmental waste, and polyester-based molded articles without generation of chlorine gas have been desired.

[0004] Known methods for remedying such disadvantages include ethylene vinyl alcohol copolymer (EVOH) and vinylidene chloride (PVDC) having excellent gas barrier properties.
And a method using a molded article made of polyethylene-2,6-naphthalate resin (hereinafter referred to as PEN) having excellent gas barrier properties.

However, in such a molded article, when PVC and other barrier resin are multi-layered, kogation is generated in the molded article, the barrier property is deteriorated under high humidity, and furthermore, in the case of reuse, It has disadvantages such as separation problems. Further, when PEN is used, it is a typical crystalline polymer due to the molecular structure of PEN, and its melting temperature is as high as 270 ° C., so that the crystal nucleus cannot be melted unless the molding temperature during melting is high. As a result, cloudiness is generated, and the orientation is extremely high at the time of stretching, so that there is a disadvantage that clouding due to crystal orientation occurs and transparency is impaired, and improvement thereof has been desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester copolymer resin suitable for molded articles for packaging requiring excellent gas barrier properties and transparency, and a gas using the polyester copolymer resin of the present invention. An object of the present invention is to provide a multilayer molded article having excellent barrier properties and transparency.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made by focusing on the above-mentioned problems, and as a result of intensive studies on polyester copolymer resins suitable for molded articles for packaging which do not have the above-mentioned drawbacks, has revealed gas barrier properties and transparency. Excellent in UV cut, and PE
The present inventors have found a polyester copolymer resin excellent in compatibility with T and capable of improving the above-mentioned disadvantages, and have reached the present invention.

That is, in the present invention, 50 to 92 mol% of ethylene isophthalate units and 5 to 92 mol% of ethylene terephthalate units are used.
47 mol% and ethylene-2,6-naphthalate unit 3
４５45 mol% as a component, an oxygen permeability coefficient of 3.0 cc · mm / m ² · day · atm or less, and a light transmittance of 85.
%, Excellent in gas barrier property, transparency and UV cut property having a property of ultraviolet absorption wavelength of 340 nm or less,
Further, it is a multilayer molded article using a polyester copolymer resin having excellent compatibility with a polyethylene terephthalate resin and the polyester copolymer resin of the present invention.

The multilayer molded article comprises an intermediate layer and / or an innermost layer composed of 20 to 80 parts by weight of the polyester copolymer resin and 80 to 20 parts by weight of a polyethylene terephthalate-based resin having a polyethylene terephthalate unit as a main component;
The oxygen transmission coefficient formed from the outermost layer made of polyethylene terephthalate resin is 3.0 cc / m ² · day · atm or less, the light transmittance is 85% or more, and the ultraviolet absorption wavelength is 330.
It is a polyester multilayer molded product having a characteristic of not more than nm.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyester copolymer resin of the present invention contains 50 to 92 mol%, preferably 70 mol% or more of ethylene isophthalate units, and 5 to 47 mol%, preferably 10 mol% or more of ethylene terephthalate units. A polyester copolymer resin obtained by copolymerizing 3 to 45 mol%, preferably 5 mol% or more of ethylene-2,6-naphthalate unit, wherein ethylene isophthalate unit is 5
If the amount is less than 0 mol%, the effect of gas barrier properties cannot be obtained, and if the amount of ethylene terephthalate unit is less than 5 mol%, compatibility with PET cannot be obtained when melt-mixed with PET by an extruder. For this reason, the molded product becomes cloudy, and when the amount of the ethylene-2,6-naphthalate unit is less than 3 mol, the effect of the UV cut property cannot be obtained.

The polyester copolymer resin of the present invention comprises isophthalic acid or its ester-forming derivative and terephthalic acid or its ester-forming derivative and 2,
6-naphthalenedicarboxylic acid or an ester-forming derivative thereof and ethylene glycol are synthesized by reacting them under ordinary reaction conditions in the presence of a catalyst, and a part of the acid component is converted into a small amount of hexahydroterephthalic acid, Hexahydroisophthalic acid, hydroxybenzoic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfondicarboxylic acid, diphenoxyethanedicarboxylic acid, 3,5-dicarboxybenzenesulfonic acid, oxalic acid, succinic acid, glutaric acid, sebacic acid, etc. And one or more of these ester-forming derivatives.

In addition, a part of ethylene glycol is converted to a small amount of cyclohexane dimethanol, 1,2-propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentylene glycol, 1,4-bis. It may be replaced by one or more of hydroxybenzene and polyalkylene glycol such as polyethylene glycol, polytetramethylene glycol, and polypropylene glycol. Further, a trifunctional or higher functional compound, for example, glycerin, pentaerythritol, trimellitic acid, and 5-hydroxyisophthalic acid may be used to some extent in a substantially linear polymer.
For example, it may be replaced with p-phenylphenol, benzyloxybenzoic acid, naphthalene monocarboxylic acid, polyethylene glycol monomethylene ether, or the like.

The polyethylene terephthalate resin (PET) in the present invention is a resin containing ethylene terephthalate units as a main component, and its content is preferably
The resin contains at least 80% by weight of the resin. Examples of the copolymerizable component include the above-mentioned dicarboxylic acids and glycols. The IV of PET is preferably 0.4 to
1.2, more preferably 0.6 to 1.0.

The multilayer molded article of the present invention comprises 20 to 80 parts by weight of the specific polyester copolymer resin and 80 to 20 parts of a resin mainly composed of polyethylene terephthalate resin.
A multilayer molded article having an intermediate layer and / or an innermost layer composed of parts by weight and a polyethylene terephthalate resin as an outermost layer, and a thickness ratio of the outermost layer, the intermediate layer and the innermost layer is 0.5 to
3: 4-9: 0.5-3 is preferred.

The method for producing a multilayer molded product is as follows: injection molding for forming a multilayer by stretch blow molding, direct blow molding, etc., multilayer extrusion molding of a film, sheet, etc., and further heating, pressurizing, vacuum, Examples of the method include molding such as compression, but the method is not particularly limited thereto.

The intrinsic viscosity (hereinafter, referred to as IV) of the polyester copolymer resin of the present invention is determined by the range in which melt extrusion can be performed, melt mixing with commonly used PET, and mechanical properties of the obtained molded article. IV = 0.4-1.0, preferably 0.6-0.85.

If necessary, a small amount of another polymer can be added to or mixed with the polyester copolymer resin of the present invention. In this case, the properties of the polyester copolymer resin are not substantially changed. It is preferred to do so. Examples of these additives or mixtures include polyamides, polyolefins, and other polyesters. If necessary, the polyester copolymer resin may be a matting agent such as titanium dioxide or alumina oxide, a stabilizer such as phosphoric acid, phosphorous acid and their esters, an antioxidant, an ultraviolet absorber, a fluorescent brightening agent. Agents or additives such as pigments and dyes may be included.

[0018]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. First, the main methods of measuring physical properties are as follows. (1) Resin composition Measured by H-NMR (500 MHz).

(2) Intrinsic viscosity (IV) It was measured at a temperature of 30 ° C. with a mixed solvent of phenol / tetrachloroethane (weight ratio: 6/4).

(3) Oxygen Permeability Coefficient OX-TRAN100 oxygen permeability meter (MOCON
Was measured at a temperature of 25 ° C. and a relative humidity of 50%.

(4) Light transmittance DIRECT. READING. HAZE. METER
(Manufactured by Toyo Seiki Seisaku-sho, Ltd.).

(5) UV cut property Measured by a spectrophotometer UV-210A (manufactured by Shimadzu Corporation).

The polyester copolymer resin used;
The PET resin is as follows. (A) Polyester copolymer resin The polyester copolymer resin of the present invention is subjected to an ester exchange reaction between dimethyl isophthalate, dimethyl terephthalate and dimethyl 2,6-naphthalenedicarboxylate and ethylene glycol in an autoclave in the presence of a catalyst. An initial condensate was produced by a usual transesterification method, and the initial condensate was polycondensed by a normal polycondensation method to obtain a polyester copolymer resin. Table 1 shows the obtained polyester copolymer resins.

[0024]

[Table 1]

(B) PET resin PET resin manufactured by Nihon Unipet with IV = 1.0

Examples 1 to 3 and Comparative Example 1 A 0.1 mm-thick (unstretched) multi-layer sheet was obtained using a press sheet molding machine manufactured by SHINTO using each of the above resins. Table 2 shows the evaluation results of the oxygen transmission coefficient, light transmittance, and ultraviolet absorption wavelength of the sheet.

[0027]

[Table 2]

As is clear from Table 2, the polyester copolymer resin of the present invention has an oxygen permeability of ^2.5 cc · mm / m ² · day.
-Atm or less, light transmittance of 85% or more, and ultraviolet absorption wavelength of 340 nm or less, exhibiting excellent gas barrier properties, transparency, and UV cut properties.

Examples 4 and 5 and Comparative Example 2 The thickness ratio of the outer layer, the intermediate layer and the inner layer was 1: 8: 1 using a multilayer stretch blow molding machine manufactured by Nissei ASB, and the polyester copolymer resin (A) was used. Layer consisting of a mixture of
A polyester multi-layer stretch blow-molded product having an outer layer made of ET (full capacity: 500 cc) was obtained. Table 3 shows the evaluation results of the oxygen transmission coefficient, the light transmittance, and the ultraviolet absorption wavelength of the stretch blow-molded product.

[0030]

[Table 3]

As is clear from Table 3, the polyester-based multi-layer stretch blow-molded article using the polyester copolymer resin of the present invention has an oxygen permeability coefficient of 1.5 cc · mm / m ² · day · at.
m or less, the light transmittance is 85% or more, and the ultraviolet absorption wavelength is 3
30 nm or less, excellent gas barrier properties, transparency,
It shows UV cut properties.

The thickness ratio of the outer layer, the intermediate layer and the inner layer is 1: 8: 1 using a homemade direct blow molding machine, and the intermediate layer comprising a mixture of the polyester copolymer resin (B) and PET and the outer layer comprising PET. Polyester-based multi-layer blow-molded product consisting of an inner layer and an inner layer (full capacity 270cc)
I got The polyester multi-layer direct blow molded product using the polyester copolymer resin of the present invention has an oxygen permeability coefficient of 2.3 cc · mm / m ² · day · atm and a light transmittance of 88.
%, And the ultraviolet absorption wavelength is 355 nm, showing excellent gas barrier properties, transparency, and UV cut properties.

The thickness ratio of the outer layer, the intermediate layer and the inner layer was 1: 8: 1 using a home-made multi-layer sheet molding machine, and the intermediate layer made of a mixture of the polyester copolymer resin (A) and PET was
An outer layer and inner layer polyester-based multilayer sheet molded article (thickness: 0.3 mmt) made of ET was obtained. Further, a 3 × 3 times stretched film molded product was obtained using a film stretching machine manufactured by Toyo Seiki. The stretched polyester film molded product using this polyester copolymer resin has an oxygen permeability coefficient of 1.3 cc · mm.
/ m ² · day · atm or less, light transmittance 93%, UV absorption wavelength 355 nm or less, excellent gas barrier properties,
It shows transparency and UV cut properties.

[0034]

The polyester copolymer resin of the present invention has improved gas barrier properties due to the molecular structure of the ethylene isophthalate unit constituting the copolymer resin, and has an improved ethylene copolymer.
UV-cutting property is improved from the molecular structure of 2,6-naphthalate unit, and P
Excellent compatibility with ET. Further, by the randomization effect of the copolymerization, the crystallization rate is slowed down and the transparency is excellent, so the multilayer molded article having the copolymer resin as the intermediate layer or the innermost layer has high transparency, In addition, it has features of excellent UV cut properties and gas barrier properties.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidetoshi Ninomiya 10-24 Toyocho, Tsuruga-shi, Fukui Prefecture Toyobo Co., Ltd.

Claims (2)

[Claims] 1. An ethylene isophthalate unit of 50 to 92.
Mol%, ethylene terephthalate unit 5 to 47 mol% and ethylene 2,6-naphthalate unit 3 to 45 mol%
Having a oxygen transmission coefficient of 3.0 cc · mm
/ m ² · day · atm or less, a polyester copolymer resin having a light transmittance of 85% or more and an ultraviolet absorption wavelength of 340 nm or less. 2. The polyester copolymer resin 20 according to claim 1,
An intermediate layer and / or an innermost layer composed of 80 to 20 parts by weight and a polyethylene terephthalate resin having an ethylene terephthalate unit as a main component; and an outermost layer composed of a polyethylene terephthalate resin having an ethylene terephthalate unit as a main component. Having an oxygen permeability coefficient of 3.
Polyester multilayer molded article having a characteristic of 0 cc · mm / m ² · day · atm or less, a light transmittance of 85% or more, and an ultraviolet absorption wavelength of 330 nm or less.