KR101546316B1 - Molded article of multi-layered polyester resin - Google Patents

Abstract

Disclosed is a multilayer polyester resin molded article capable of reducing a phenomenon in which a heavy metal component migrates from a polyester resin. The multi-layered polyester resin molded article may comprise a surface layer made of polyethylene terephthalate including a metal-based catalyst selected from the group consisting of a germanium-based catalyst, a titanium-based catalyst and a mixture thereof, and a back surface made of polyethylene terephthalate containing an antimony- Layer. Here, the content of the germanium-based catalyst, the titanium-based catalyst and the antimony-based catalyst is 1 to 300 ppm for the polyethylene terephthalate resin, the thickness of the surface layer is 0.1 to 3 mm, To 10 mm.

Polyester resin, heavy metal, catalyst, transition, germanium, titanium, antimony

Description

[0001] The present invention relates to a multi-layered polyester resin molded article,

The present invention relates to a multilayer polyester resin molded article, and more particularly, to a multilayered polyester resin molded article capable of reducing migration of a heavy metal component from a polyester resin.

Polyethylene terephthalate (hereinafter referred to as "PET") is a polyester resin obtained by polymerizing a diacid component typified by terephthalic acid and a diol component represented by ethylene glycol, , Films, and the like, but also in the production of packaging materials such as bottles and sheets. BACKGROUND ART Polyethylene terephthalate is widely known and is generally produced by esterification reaction of terephthalic acid and ethylene glycol at a temperature of about 250 DEG C to form bis (hydroxyl ethyl) terephthalate (bis (hydroxyethyl) terephthalate) And then synthesized bis (hydroxyethyl) terephthalate is polycondensated at a degree of vacuum of about 1 torr and a temperature of about 280 DEG C to prepare polyethylene terephthalate. Here, the esterification reaction is carried out as an autocatalytic reaction of terephthalic acid without any catalyst, but the polycondensation reaction must be carried out under a polycondensation reaction catalyst.

At present, antimony-based catalysts such as antimony dioxide are used as polycondensation reaction catalysts in the production of most polyethylene terephthalate (PET). However, since antimony is a kind of heavy metal, there is a movement to regulate the amount of the antimony-based catalyst or the amount of antimony leached from the PET container in consideration of the case where PET is used as a packaging container for foods, beverages, ), EU directives and Japan have already restricted the migration amount of heavy metals such as antimony from PET containers. Therefore, in recent years, PET synthesis technology using a titanium-based or germanium-based catalyst as a specific gravity metal polycondensation catalyst other than antimony has been developed. Nevertheless, antimony-based catalysts have been widely used as PET polycondensation catalysts due to advantages such as production yield and price.

It is an object of the present invention to provide a multilayer polyester resin molded article which can reduce the migration of a heavy metal component such as antimony, which is a residual catalyst component, from a polyester resin molded article.

Another object of the present invention is to provide a multilayered polyester resin molded article which can not only remarkably reduce the amount of heavy metal leaching but also can be economically produced.

In order to achieve the above object, the present invention provides a process for producing a polyethylene terephthalate comprising a surface layer composed of polyethylene terephthalate containing a metal-based catalyst selected from the group consisting of a germanium-based catalyst, a titanium-based catalyst and a mixture thereof and an antimony- And a back layer made of the polyester resin. Here, the content of the germanium-based catalyst, the titanium-based catalyst and the antimony-based catalyst is 1 to 300 ppm for the polyethylene terephthalate resin, the thickness of the surface layer is 0.1 to 3 mm, To 10 mm.

The polyester resin molded article according to the present invention is advantageous in that heavy metal migration of a heavy metal component such as antimony, which is a residual catalyst component, is reduced, the amount of leaching of heavy metal is remarkably reduced, and it can be produced economically .

Hereinafter, the present invention will be described in detail.

The polyester resin molded article according to the present invention has a multi-layer structure including a surface layer and a back layer. Wherein the surface layer is made of polyethylene terephthalate containing a metal-based catalyst selected from the group consisting of a germanium-based catalyst, a titanium-based catalyst and a mixture thereof, and the backside layer includes an antimony-based catalyst Polyethylene terephthalate. The surface layer is a surface exposed to the outside of the polyester resin molded article and may be, for example, a surface that comes into contact with a human body such as a sheet or a film, or an inner surface that comes into contact with a beverage in the case of a bottle container. The polyester resin molded article according to the present invention may have not only the structure of the surface layer-back surface layer but also at least one surface layer and at least one back surface layer, such as a surface layer-back surface- The thickness of the surface layer is usually 0.1 to 3 mm, and the thickness of the back layer is usually 1 to 10 mm. Here, if the thickness of the surface layer is too small, the amount of leaching of antimony heavy metal can not be effectively reduced, and if the thickness of the surface layer is too large, the production cost of the polyester resin molded article becomes high.

The polyester resin constituting the surface layer and the back layer is a copolymer produced by a polycondensation reaction of a diacid component and a diol component. In the present invention, the above-mentioned divalent acid component contains at least 80 mol% of a terephthalic acid component, and optionally up to 20 mol%, preferably up to 10 mol%, of other diacid components. That is, the divalent acid component used in the polyester resin of the present invention contains 80 to 100 mol% of terephthalic acid and 0 to 20 mol%, preferably 1 to 10 mol%, of other diacid components. If the content of the terephthalic acid component is less than 80 mol% with respect to the total dicarboxylic acid component, the heat resistance of the polyester resin may be lowered. Other divalent acid components that can be used with the terephthalic acid include phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, 4,4'-stearyl Aromatic dicarboxylic acids having 6 to 14 carbon atoms in the aromatic moiety such as trans-4,4'-stilbene dicarboxylic acid, malonic acid, succinic acid, glutaric acid, The compounds of the present invention may be selected from the group consisting of glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonane dicarboxylic acid, An aliphatic moiety having 2 to 12 carbon atoms in the aliphatic moiety such as decane dicarboxylic acid, dodecane dicarboxylic acid, cyclohexanediacetic acid and cyclohexanedicarboxylic acid. And dicarboxylic acid. In the present specification, the above-mentioned divalent acid component is capable of forming an ester bond of polyester, and not only dicarboxylic acid but also alkyl ester thereof (e.g., dimethyl or diethyl ester), acid chloride thereof acid chloride compounds, anhydrides thereof, and the like.

In the present invention, the diol component comprises at least 80 mol% of an ethylene glycol component, and optionally up to 20 mol%, preferably up to 10 mol%, of other diol components. Here, if the content of ethylene glycol is less than 80 mol% based on the total diol component, physical properties and processing problems of the polymer material may occur due to a rapid change in the physical properties of the PET resin. Examples of other diol components that can be used in combination with ethylene glycol include aliphatic diols having 3 to 16 carbon atoms. Specific examples thereof include diethylene glycol, triethylene glycol, propanediol, butanediol, Pentanediol, hexanediol, cyclohexanedimethanol, cyclobutanediol, and the like. In order to improve the physical properties of the polyester resin, the polyester resin according to the present invention may further contain a trihydric or higher polyhydric acid component such as trimellitic anhydride (TMA) and trimethylol ethane (Trimethylol ethane), trimethylol propane, and the like. When the trivalent or more polyvalent alcohol component is used, the amount of the polyhydric alcohol component to be used is 0 to 10% by weight, preferably 0.01 to 3% by weight based on the bivalent acid component. When the trivalent or more polyvalent alcohol component is used, Is 0 to 10% by weight, preferably 0.01 to 3% by weight, based on the diol component.

The germanium-based catalyst, the titanium-based catalyst and the antimony-based catalyst contained in the polyester resin according to the present invention are usually used for the polycondensation reaction of a polyester resin. The germanium- Germanium oxide may be used. As the titanium-based catalyst, tetraethyl titanate, acetyl tripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, polybutyl titanate, ethylacetoacetic acid Ester titanate, isostearyl titanate, titanium dioxide and the like can be used. As the antimony catalyst, antimony oxide, antimony triacetate and the like can be used. The amount of the catalyst to be used is 1 to 300 ppm, preferably 3 to 200 ppm, with respect to the polyethylene terephthalate resin constituting the surface layer or the back layer. When the amount of the catalyst used is too small in the surface layer and the back surface layer of the polyester resin according to the present invention, the polycondensation reaction of the polyester resin is not effectively carried out, and when the amount is too large, Or acts only as an impurity of the polyester resin .

The polyester resin according to the present invention can be produced in two steps of an esterification reaction or an ester exchange reaction, and a polycondensation reaction like a conventional polyester resin. Here, the molar ratio of the total alcohol component usage amount (G) to the total acid component usage amount (A) is preferably 1.1 to 1.8. When the ratio (G / A) is less than 1.1, the unreacted acid component remains in the polymerization reaction and the transparency of the resin is lowered. When the ratio is more than 1.8, the polymerization reaction rate is too slow to lower the productivity of the resin . The multilayered polyester molding according to the present invention can be molded into a multilayered molded article such as sheet, film, panel, bottle, preform or the like by a conventional extrusion molding, injection molding, have.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. The following examples are intended to further illustrate the present invention, and the scope of the present invention is not limited by these examples.

[Example 1] Production of polyester resin molded article

85 Kg of terephthalic acid and 35 Kg of ethylene glycol as main materials and 10 g of germanium oxide as a main catalyst were subjected to a melt polymerization process to obtain a polyethylene terephthalate having an intrinsic viscosity of 0.57 dl / g and then pelletized And solid state polymerization were carried out in a nitrogen atmosphere at 210 DEG C to obtain polyethylene terephthalate having an intrinsic viscosity of 0.80 dl / g. Polyethylene terephthalate prepared by the same method using an antimony-based polycondensation catalyst was used as a material for the backing layer, using polyethylene terephthalate as a material of the surface layer and a sheet extruder (Breyer Layer structure PET sheet having a total thickness of 2 mm (surface layer thickness: 0.3 mm, back layer thickness: 1.7 mm) was produced. During sheet extrusion, extruder barrel / die / roller temperatures were 280/280/60 ° C respectively. As a result of leaching test on the produced sheet with antimony which is a heavy metal component, the leaching amount of antimony was 0.002 ppm.

[Example 2] Production of polyester resin molded article

85 Kg of terephthalic acid and 35 Kg of ethylene glycol were used as main materials and 1 g of a Ti catalyst (grade name: Hombifast PC) of Sachtleben Chemie GmbH, Germany was used as a main catalyst to carry out a melt polymerization process to give an intrinsic viscosity of 0.57 dl / g Of polyethylene terephthalate was obtained and then pelletized and solid-phase synthesized in a nitrogen atmosphere at 210 캜 to obtain polyethylene terephthalate having an intrinsic viscosity of 0.80 dl / g. Polyethylene terephthalate prepared by the same method using an antimony-based polycondensation catalyst was used as a material for the back layer and polyethylene terephthalate was used as a surface layer material. Layer structure PET sheet having a total thickness of 2 mm (surface layer thickness: 0.3 mm, back layer thickness: 1.7 mm) was produced. During sheet extrusion, extruder barrel / die / roller temperatures were 280/280/60 ° C respectively. The resultant sheet was subjected to a leaching test on antimony which is a heavy metal component. As a result, the leaching amount of antimony was 0.003 ppm.

[Comparative Example 1] Production of polyester resin molded article

As the antimony-based polycondensation catalyst, polyethylene terephthalate was prepared using antimony oxide and a PET sheet having a thickness of 4 mm was produced using a sheet extruder (manufactured by Breyer). During sheet extrusion, extruder barrel / die / roller temperatures were 280/280/60 ° C respectively. As a result of leaching test on the produced sheet with antimony which is a heavy metal component, the leaching amount of antimony was 0.018 ppm.

Claims (5)

Based catalyst comprising a metal-based catalyst selected from the group consisting of germanium-based catalysts, titanium-based catalysts, and mixtures thereof, And a back layer which is made of polyethylene terephthalate containing an antimony-based catalyst and is a surface which is not in contact with food, The thickness of the surface layer is 0.1 to 3 mm, the thickness of the back layer is 1 to 10 mm, Wherein the content of the germanium-based catalyst, the titanium-based catalyst and the antimony-based catalyst is 1 to 300 ppm, respectively, with respect to the polyethylene terephthalate resin. delete delete The method of claim 1, wherein the germanium-based catalyst is selected from the group consisting of germanium oxide, and the titanium-based catalyst is selected from the group consisting of tetraethyl titanate, acetyl tripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, Wherein the antimony oxide is selected from the group consisting of antimony oxide, antimony oxide and antimony triacetate, wherein the antimony oxide is selected from the group consisting of ethyl acetoacetic ester titanate, isostearyl titanate, and titanium dioxide. A molded article for food packaging comprising a polyester resin. The polyester resin as claimed in claim 1, wherein the polyester resin constituting the surface layer and the backing layer is a copolymer produced by a polycondensation reaction of a diacid component and a diol component, and the diacid component comprises 80 to 100 mol% of a terephthalic acid component And wherein the diol component comprises 80 to 100 mol% of an ethylene glycol component.