Cup-type multilayered container

Abstract

The present invention relates to a multilayered container obtained by thermoforming a multilayered precursor comprising: inner and outer layers obtained from an ethylene terephthalate polyester resin;and at least one layer of an intermediate layer obtained from at least a low crystallinity ethylene terephthalate polyester resin and a gas barrier aromatic polyamide resin. The difference in refractive index ([delta]RI), which is represented by equation (1), for the low crystallinity ethylene terephthalate polyester resin and gas barrier aromatic polyamide resin [delta]RI=absolute value of (RIE-RIA) (1), wherein RIE and RIA represent the respective refractive indices after injection molded sheets obtained from the low crystallinity ethylene terephthalate polyester resin and the gas barrier aromatic polyamide resin have been stretched three-fold in one axial direction, is 0.03 or less, and haze of the side surface of the container is 5% or less. As a result, the container has a multilayered structure obtained from inner and outer layers made of polyester resin and an intermediate layer made of a blend of a polyester resin and an aromatic polyamide resin, and satisfies requirements forexcellent transparency, gas barrier properties and inter-layer adhesiveness.

Description

technical field

[0001] The present invention relates to a multilayer container including a polyester resin, and more particularly, to a cup-type multilayer container excellent in gas barrier properties, interlayer adhesion, and transparency. Background technique

[0002] Polyester resins represented by polyethylene terephthalate have excellent properties such as moldability, transparency, mechanical strength, and chemical resistance, and thus are widely used in the field of packaging containers. In order to improve the gas barrier properties of containers including polyester resins to gases such as oxygen, it is proposed to form a saponified product of ethylene-vinyl acetate copolymer or a layer of polyamide as an intermediate layer between an inner layer and an outer layer of a polyester resin. Packaging materials with multi-layer structure. In order to further improve the gas barrier properties of the packaging material of the above multilayer structure, it has also been ...

Examples

Embodiment 1

[0127] A multi-layer sheet was made by using PET to form the inner and outer layers, dry blending APET1 and PA together at a ratio of 70:30 to form the middle layer, and setting the temperature of the molding machine at 280°C.

[0128] The sheet was made to have a thickness of 1.2 mm, and the intermediate layer was 10% by weight of the entire sheet. Next, the sheet was heated again at 100° C. to form a cup, and thus a multilayer container having a drawing ratio of 1.67 and an inner volume of 350 cc was produced. The resulting container was measured for side haze, occurrence of delamination, and oxygen barrier property according to the methods described above.

[0129] Furthermore, the dried APET1 was fed into a hopper of an injection molding machine, and injection molded while setting the temperature of the cylinder at 280° C. to obtain an injection molded plate having a size of 90×90×1.5 mm. The injection-molded plate was uniaxially stretched 3 times by the above method to o...

Embodiment 2

[0131] By using APET1 as a base material, the granular masterbatch resin (MB1) which contained an oxidation catalyst in the resin composition in the amount of 500 ppm of metal conversion was prepared by the said method. Here, the temperature of the barrel was maintained at 280°C.

[0132] By using a multilayer sheet-forming machine, a multilayer container and a stretch sheet were fabricated in the same manner as in Example 1, except that an intermediate layer was formed by using a dry blend of MB1 and PA in a ratio of 70:30. Then measure their properties.

Embodiment 3

[0134] A multilayer container was produced in the same manner as in Example 1 except that APET2 was used instead of APET1, and its properties were measured.

[0135] In addition, a stretched sheet was produced in the same manner as in Example 1, except that dry APET2 was supplied to the hopper of an injection molding machine to form an injection-molded sheet thereof. The refractive index of the produced stretched sheet was measured.

technical field

[0001] The present invention relates to a multilayer container including a polyester resin, and more particularly, to a cup-type multilayer container excellent in gas barrier properties, interlayer adhesion, and transparency. Background technique

[0002] Polyester resins represented by polyethylene terephthalate have excellent properties such as moldability, transparency, mechanical strength, and chemical resistance, and thus are widely used in the field of packaging containers. In order to improve the gas barrier properties of containers including polyester resins to gases such as oxygen, it is proposed to form a saponified product of ethylene-vinyl acetate copolymer or a layer of polyamide as an intermediate layer between an inner layer and an outer layer of a polyester resin. Packaging materials with multi-layer structure. In order to further improve the gas barrier properties of the packaging material of the above multilayer structure, it has also been ...

Examples

Embodiment 1

[0127] A multi-layer sheet was made by using PET to form the inner and outer layers, dry blending APET1 and PA together at a ratio of 70:30 to form the middle layer, and setting the temperature of the molding machine at 280°C.

[0128] The sheet was made to have a thickness of 1.2 mm, and the intermediate layer was 10% by weight of the entire sheet. Next, the sheet was heated again at 100° C. to form a cup, and thus a multilayer container having a drawing ratio of 1.67 and an inner volume of 350 cc was produced. The resulting container was measured for side haze, occurrence of delamination, and oxygen barrier property according to the methods described above.

[0129] Furthermore, the dried APET1 was fed into a hopper of an injection molding machine, and injection molded while setting the temperature of the cylinder at 280° C. to obtain an injection molded plate having a size of 90×90×1.5 mm. The injection-molded plate was uniaxially stretched 3 times by the above method to o...

Embodiment 2

[0131] By using APET1 as a base material, the granular masterbatch resin (MB1) which contained an oxidation catalyst in the resin composition in the amount of 500 ppm of metal conversion was prepared by the said method. Here, the temperature of the barrel was maintained at 280°C.

[0132] By using a multilayer sheet-forming machine, a multilayer container and a stretch sheet were fabricated in the same manner as in Example 1, except that an intermediate layer was formed by using a dry blend of MB1 and PA in a ratio of 70:30. Then measure their properties.

Embodiment 3

[0134] A multilayer container was produced in the same manner as in Example 1 except that APET2 was used instead of APET1, and its properties were measured.

[0135] In addition, a stretched sheet was produced in the same manner as in Example 1, except that dry APET2 was supplied to the hopper of an injection molding machine to form an injection-molded sheet thereof. The refractive index of the produced stretched sheet was measured.

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