JP2009280264A - Strip for packaging container, method of manufacturing the strip for packaging container and packaging container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a strip for a packaging container, a method of manufacturing the strip for the packaging container, and the packaging container that eliminates an anchor coating agent or adhesive layer by directly laminating a heat-seal polyolefin-outermost sealant layer on a base material made of polypropylene. <P>SOLUTION: The strip 6 for the packaging container protects an overlapped part 3 of a packaging material to form the packaging container 1 from the packaging material. The strip 6 includes a base material 6b containing polypropylene obtained by using a metallocene catalyst, and a heat-seal outermost layer 6a made of polyethylene obtained by using a metallocene catalyst laminated directly on the both faces of the base material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a strip for a packaging container, a manufacturing method of the strip, and a packaging container, and more particularly, reinforces the overlapping portion of the packaging material in the packaging container such as liquid food, and the liquid container penetrates the end surface of the container container. The present invention relates to a strip to be protected, a method for manufacturing the strip, and a packaging container using the strip.

For packaging containers for milk, juice, sake, shochu, mineral water and other beverages, for example, a web-like packaging material with a crease line attached to a laminate consisting of a paper layer / plastic layer is sealed by a longitudinal vertical line seal. Molded into a tube shape, filled with the contents in the tube-shaped packaging material, applied with a horizontal line seal in the transverse direction of the tube-shaped packaging material, first molded into a pillow-shaped primary shape, and the packaging material was strip-shaped In this case, it is cut into individual pieces at regular intervals, folded along a crease line, and formed into a final shape. The final shapes include brick shapes (parallelepipeds), hexagonal column shapes, octagonal column shapes, tetrahedral shapes, and the like.

In a gable top (roof type) paper packaging container, paper packaging material is cut into a predetermined shape, blanks sealed in the vertical direction of the container are obtained, and after the bottom of the blanks is sealed in the filling machine, milk is introduced from the top opening. Filled with juice or other beverage filling and sealed at the top. These packaging materials have the appearance design of the packaging container product printed on the surface thereof.

When the container is formed by overlapping the edges of the packaging material, in order to firmly bond the overlapped part, and when the end surface of the formed container wall is in direct contact with the internal liquid, packaging is performed from that end surface. In order to prevent the contents from penetrating into the material or leaking to the outside, the strip covers the end wall of the overlapped portion inside the container and is heat sealed.

As shown in FIG. 1, an example of a paper packaging container includes a brick-shaped paper packaging container 1, in which a horizontal seal fin is folded along a crease line on a top 2 and a bottom, and a vertical seal 3 extends from the top 2 to a bottom through a side wall. Are formed. A strip 6 for protecting the end surface 5 of the vessel wall 4 from liquid permeation is sealed to the inner surface of the container at the overlapping portion of the vertical seal 3.

The strip 6 includes a base material (center) layer 6b and a heat-sealable polyolefin outermost sealant layer 6a. When laminating them, an anchor coating agent or an adhesive is used.
There has been proposed a strip tape in which a specific ethylene-methacrylic acid-alkyl acrylate ester random copolymer is laminated with an adhesive layer as a component. (See Patent Document 1)

As the base material (center) layer, mechanical strength, barrier properties, thermal stability, and the like are taken into consideration, and various materials use high-density polyethylene, polyester, polyethylene vinyl alcohol copolymer (EVOH), and the like. .

JP 2001-354916 A

Polypropylene is one of the most widely used thermoplastic resins as a typical general-purpose plastic. Propylene (CH3CH = CH2) purified from naphtha decomposition and the like is subjected to addition polymerization in the presence of a catalyst. can get. Its properties are light weight, relatively high strength, high heat resistance, high resistance to various chemicals, solvents, etc., and easy to process, so it can be used for daily packaging, various packaging materials (films, containers), industrial parts. Widely used as a material.

Although it is a polypropylene having excellent properties, it is unsuitable for heat adhesion with the heat sealable polyolefin outermost sealant layer. Therefore, as described above, an anchor coat agent or an adhesive is used between the base material layer and the sealant layer.

In the present invention, the above-mentioned disadvantages are solved, and a heat-sealable polyolefin outermost sealant layer is directly laminated on a polypropylene base material, thereby eliminating the need for an anchor coat agent or an adhesive layer, and a packaging container strip and packaging container An object of the present invention is to provide a manufacturing method of a strip and a packaging container.

The strip for packaging container according to the present invention is a strip for packaging container that protects the overlapping portion of the packaging material in order to form the packaging container from the packaging material, and is obtained by using polypropylene obtained by using a metallocene catalyst (that is, a metallocene catalyst). A base material comprising polypropylene polymerized using (metallocene PP),
It consists of a heat seal outermost layer made of polyethylene obtained by using a metallocene catalyst directly laminated on at least one side of a substrate.

In a preferred embodiment of this invention, the substrate is a single layer made of polypropylene obtained using a metallocene catalyst.

In a preferred embodiment of the present invention, the substrate comprises a core layer made of polypropylene obtained using a metallocene catalyst, and a blend of polypropylene obtained using a metallocene catalyst and polyethylene obtained using a metallocene catalyst. A multilayer having an outer layer.

In a preferred embodiment of the invention, the outer layer blend comprises 100 parts by weight of polypropylene and 5-50 parts by weight of polyethylene.

In a preferred embodiment of the invention, the outer layer blend comprises 100 parts by weight of polypropylene and 10-20 parts by weight of polyethylene.

In a preferred embodiment of the present invention, the base material has a thickness of 10 to 60 μm, and the outermost heat seal layer has a thickness of 5 to 30 μm.

In a preferred embodiment of the present invention, the thickness of the base material is 20 to 40 μm, and the thickness of the outermost heat seal layer is 10 to 20 μm.

In a preferred embodiment of the present invention, the polypropylene has a melt flow rate of 1 to 30 g / 10 min. (230 ° C.), and the polyethylene has a melt flow rate of 0.5 to 20 g / 10 min. (190 ° C.).

In a preferred embodiment of the present invention, the polypropylene has a melt flow rate of 2 to 10 g / 10 min. (230 ° C.), and the melt flow rate of polyethylene is 2 to 10 g / 10 min. (190 ° C.).

The method for producing a packaging container strip according to the present invention is a method for producing a packaging container strip that protects the overlapping portion of the packaging material in order to form the packaging container from the packaging material,
It includes directly laminating two layers made of polyethylene obtained using a metallocene catalyst on both sides of a single layer substrate made of polypropylene obtained using a metallocene catalyst.

The method for producing a packaging container strip according to the present invention is a method for producing a packaging container strip that protects the overlapping portion of the packaging material in order to form the packaging container from the packaging material,
A core layer made of polypropylene obtained using a metallocene catalyst, a blend of polypropylene obtained using a metallocene catalyst and polyethylene obtained using a metallocene catalyst, and a metallocene catalyst on both sides of the outer layer and the substrate. Directly laminating two layers of polyethylene obtained by use.

The packaging container of the present invention is a packaging container obtained by laminating the overlapping portions of the packaging material, and the container wall end surface of the overlapping portion is protected from liquid penetration by a strip,
The strip is composed of a base material containing polypropylene obtained using a metallocene catalyst and an outermost heat seal layer made of polyethylene obtained using a metallocene catalyst directly laminated on both surfaces of the base material.

The present invention having the above-described configuration functions and functions as follows.
Polypropylene (metallocene PP) obtained using a metallocene catalyst has heat-fusibility to polyethylene, particularly polyethylene obtained using a metallocene catalyst (mLLDPE).
The outermost heat seal layer made of polyethylene obtained using a metallocene catalyst is directly laminated on both sides of a base material containing polypropylene polymerized using a metallocene catalyst (metallocene PP) by coextrusion or thermocompression bonding. can do. At the time of manufacture, it is not necessary to assist by laminating an adhesive resin and an adhesive between each layer.

In a preferred embodiment of the present invention, a base material is blended with polypropylene (mPP) obtained using a metallocene catalyst and polyethylene obtained using a metallocene catalyst (mLLDPE) in the outer layer of the multilayer base material, It can be used for a single layer substrate.
A blend of polypropylene (mPP) produced using a metallocene catalyst and mLLDPE produced using a metallocene catalyst is used on the substrate side, further improving the thermal adhesion between the substrate and the heat seal layer. Thus, there is no need to laminate an adhesive resin and an adhesive.

In the embodiment of the present invention, since it is not necessary to laminate the adhesive resin and the adhesive, the entire layer thickness of the strip can be reduced.
The mechanical strength is borne by the substrate layer, and the layer thickness of the substrate remains unchanged, so that the mechanical properties of the strip can be maintained despite the thin strip.

In the embodiment of the present invention, since the thermal adhesiveness between the base material and the heat seal layer is improved, the base material can be used in the production of strips and in the simultaneous processing such as lamination (extrusion lamination) immediately after coextrusion or melt extrusion. The process of laminating the sealing layer after the film is formed may be used.

Hereinafter, embodiments of the present invention will be described in detail.
The base material in the present invention includes polypropylene obtained using a metallocene catalyst (that is, polypropylene polymerized using a metallocene catalyst (metallocene PP)).
Moreover, the heat seal layer in this invention consists of polyethylene obtained using the metallocene catalyst laminated | stacked directly on both surfaces of the base material.

Examples of the polypropylene in the present invention include a polymer having a good heat sealability and a narrow molecular weight distribution polymerized using a metallocene catalyst, or a blend polymer containing at least the polypropylene.
As this metallocene catalyst, for example, a catalyst based on a combination of a metallocene complex and an alumoxane such as a catalyst based on a combination of zirconocene dichloride and methylalumoxane.

In a preferred embodiment of the present invention, the polypropylene has a melt flow rate of 1 to 30 g / 10 min. (230 ° C.), and the polyethylene has a melt flow rate of 0.5 to 20 g / 10 min. (190 ° C.), more preferably, the polypropylene has a melt flow rate of 2 to 10 g / 10 min. (230 ° C.), and the melt flow rate of polyethylene is 2 to 10 g / 10 min. (190 ° C.).

  Examples of comonomers copolymerized with propylene or ethylene include butene-1, hexene-1, 4-methylpentene-1, and octene-1. These α-olefins may be used alone or in combination of two or more.

In an embodiment of the present invention, the substrate is a multilayer, and the multilayer is obtained using a core layer made of polypropylene obtained using a metallocene catalyst, and a polypropylene obtained using a metallocene catalyst and a metallocene catalyst. It is made of a blend with polyethylene and has an outer layer.
In this embodiment, the outer layer blend consists of 100 parts by weight of polypropylene and 5-50 parts by weight of polyethylene, more preferably the outer layer blend consists of 100 parts by weight of polypropylene and 10-20 parts by weight of polyethylene.

The strip of the present invention is used, for example, in the form of a film having a thickness of about 40 to 120 microns, and the width is usually 4 to 30 mm. In the strip tape of the present invention, the outer layer is composed of at least one heat seal layer, but may be composed of two or more polyethylene layers (heat seal layer or sealant layer). When two or more polyethylene layers are used, the two or more polyethylene layers are the same as or different from each other. The thicknesses of the polyethylene layers are the same or different.

The packaging container of the present invention is a packaging container obtained by laminating overlapping portions of packaging materials, and the container wall end surface of the overlapping portion is protected from liquid penetration by a strip. As described above, the strip comprises a base material containing polypropylene obtained using a metallocene catalyst, and a heat seal outermost layer made of polyethylene obtained using a metallocene catalyst laminated directly on the surface of the base material. A substrate layer.

The paper layer of the paper container that can be used in the present invention is usually made from kraft pulp and is required to have excellent strength and low water absorption. The types include bleached paper (FBL), unbleached paper (UBL), bleached and unbleached combined paper (DUPLEX), clay-coated paper, and multilayered laminated paper (MB).

In addition, this invention is not limited to this embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

The strip for a packaging container, the manufacturing method of the strip, and the packaging container of the present invention can be applied to packaging filled with liquid food such as juice or milk.

FIG. 1 is a perspective view and a partially enlarged view of an example of a packaging container used in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Packaging container 2 ... Container top part 3 ... Overlapping part 4 ... Container container wall 5 ... End face 6 ... Strip 6a ... Heat seal layer 6b ... Base material

Claims (12)

A packaging container strip that protects the overlapping portions of the packaging material to form the packaging container from the packaging material,
A substrate comprising polypropylene obtained using a metallocene catalyst;
An outermost heat seal layer made of polyethylene obtained by using a metallocene catalyst directly laminated on at least one side of the base material,
Packaging container strip. The strip for packaging containers according to claim 1, wherein the base material is a single layer made of polypropylene obtained by using a metallocene catalyst. The base material is a multilayer having a core layer made of polypropylene obtained using a metallocene catalyst and an outer layer made of a blend of polypropylene obtained using a metallocene catalyst and polyethylene obtained using a metallocene catalyst. The packaging container strip according to claim 1. The packaging container strip according to claim 3, wherein the blend of the outer layer comprises 100 parts by weight of the polypropylene and 5 to 50 parts by weight of the polyethylene. The packaging container strip according to claim 4, wherein the blend of the outer layer comprises 100 parts by weight of the polypropylene and 10-20 parts by weight of the polyethylene. The thickness of the substrate is 10 to 60 μm, and the thickness of the outermost heat seal layer is 5 to 30 μm.
The packaging container strip according to claim 1. The thickness of the base material is 20 to 40 μm, and the thickness of the outermost heat seal layer is 10 to 20 μm.
The strip for packaging containers according to claim 6. The melt flow rate of the polypropylene of the substrate is 1 to 30 g / 10 min. (230 ° C.) and the polyethylene has a melt flow rate of 0.5 to 20 g / 10 min. (190 ° C.)
The strip for packaging containers according to claim 1. The melt flow rate of the polypropylene of the substrate is 2 to 10 g / 10 min. (230 ° C.), and the polyethylene has a melt flow rate of 2 to 10 g / 10 min. (190 ° C.)
The strip for packaging containers according to claim 8. A method of manufacturing a packaging container strip that protects an overlapping portion of the packaging material to form a packaging container from the packaging material,
Including directly laminating two layers made of polyethylene obtained using a metallocene catalyst on both sides of a single layer substrate made of polypropylene obtained using a metallocene catalyst,
Manufacturing method for strips for packaging containers. A method of manufacturing a packaging container strip that protects an overlapping portion of the packaging material to form a packaging container from the packaging material,
A core layer made of polypropylene obtained using a metallocene catalyst, a blend of polypropylene obtained using a metallocene catalyst and polyethylene obtained using a metallocene catalyst, and a metallocene catalyst on both sides of the outer layer and the substrate. Including directly laminating two layers of polyethylene obtained using
Manufacturing method for strips for packaging containers. A packaging container obtained by laminating overlapping portions of packaging material, the container wall end surface of the overlapping portion being protected from liquid penetration by a strip,
The strip consists of a base material containing polypropylene obtained using a metallocene catalyst, and an outermost heat seal layer made of polyethylene obtained using a metallocene catalyst directly laminated on both surfaces of the base material.
Packaging container.

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