WO2003101732A1

WO2003101732A1 - Packaging material, packaging case and method for producing packaging material

Info

Publication number: WO2003101732A1
Application number: PCT/JP2003/006975
Authority: WO
Inventors: Kazuya Ono; Hiroaki Ogita; Peter Frisk
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 2002-06-04
Filing date: 2003-06-03
Publication date: 2003-12-11
Also published as: JP2004010067A; AU2003241879A1

Abstract

A packaging material which is a laminated packaging material comprising a base material, an outermost thermoplastic material layer and an innermost thermoplastic material layer, characterized in that it further comprises at least one intermediate layer provided between the base material and the innermost layer, the innermost layer and said intermediate layer comprises a polyethylene resin, and the polyethylene resin in the intermediate layer has a density higher than that of the polyethylene resin in the innermost layer; a packaging case comprising the packaging material; and a method for producing the packaging material. The packaging material uses general and inexpensive resins and also has flavor-retaining property, that is, it can provide a packaging case markedly reduced in the escape of a flavor component through the body thereof, and further, the material is excellent in heat-sealing properties.

Description

Description Packaging materials, packaging containers and methods for manufacturing packaging materials

The present invention relates to a packaging material, a packaging container, and a method for producing a packaging material having excellent fragrance retention properties. Background art

As a packaging material, there is a packaging material having a configuration in which a polyethylene is laminated on both sides of a paper base material. The packaging material is used as a gable-top container for various beverages. However, the flavor components of the contents may sorb to the polyethylene resin during storage, resulting in a change in flavor.

One example is d-limonene, a typical orange flavor component. d-Limonene is well sorbed on polyethylene. The incorporated d-limonene diffuses through the polyethylene layer. d-Limonene passes through the paper layer of the base material and is gradually released to the outside of the container. Therefore, the flavor of citrus juice stored in gable-top paper containers changes significantly.

In order to improve the heat sealability, linear polyethylene polymerized with a methyl acetate catalyst is used for the innermost layer of the container. However, due to the low density of the linear polyethylene, the loss of flavor components from the contents may be judged to be greater than when low-density polyethylene is used for the innermost layer. In order to avoid this, it is common practice to laminate a fragrance retaining resin such as a polyester resin. The container is expensive.

In packaging materials, packaging containers and methods of manufacturing packaging materials with excellent scent retention, packaging materials with excellent heat retention while using polyethylene, which has excellent heat sealing properties and is inexpensive and has a proven track record, as packaging materials '' I can't get a container. Disclosure of the invention

The present invention provides a packaging material having excellent heat-sealing properties, using a general-purpose, inexpensive resin, having a fragrance retention property such that a flavor component such as d-limonene does not escape from a container, and a method for producing a packaging container and a packaging material. The purpose is to provide.

In the present invention, the layer structure of the packaging material is such that the intermediate layer provided between the base material and the innermost layer is made of polyethylene having a higher density than the innermost layer. This achieves the above object.

The packaging material according to the embodiment of the present invention is a laminated packaging material comprising at least a base material, an outermost thermoplastic material layer, and an innermost thermoplastic material layer, wherein at least one intermediate layer is formed of the base material and the innermost layer. The inner layer and the intermediate layer are made of polyethylene resin, and the density of the polyethylene resin in the intermediate layer is higher than the density of the polyethylene resin in the inner layer.

In a packaging material containing polyethylene such as low-density polyethylene or linear low-density polyethylene, provide a polyethylene intermediate layer with a higher density than the innermost seal layer between the base material and the polyethylene innermost seal layer. This delays the sorption and diffusion of flavor components such as d-limonene. As a result, fragrance retention It has the effect of being able to improve.

The packaging container according to an aspect of the present invention is a packaging container comprising: a base material; an outermost polyethylene layer; an innermost polyethylene layer; and at least one intermediate layer provided between the base material and the innermost layer. A packaging container formed of a packaging material, wherein the density of polyethylene in the innermost layer and the intermediate layer increases continuously or discontinuously from the inside to the outside.

In containers containing low-density polyethylene or linear low-density polyethylene, d-limonene is formed by providing a density gradient in the innermost sealing layer and intermediate layer of polyethylene that increases in density from inside to outside. Delays the sorption and diffusion of flavor components such as As a result, it has the effect of improving fragrance retention.

A method for producing a packaging material according to an embodiment of the present invention is a method for producing a laminated packaging material comprising at least a substrate, an outermost thermoplastic material layer, and an innermost thermoplastic material layer, wherein at least one intermediate layer is a substrate. The innermost layer and the intermediate layer are made of polyethylene resin, the density of the polyethylene resin of the intermediate layer is higher than the density of the polyethylene resin of the innermost layer, It is characterized in that a metal deposition film is formed on the film of the layer.

In a method for producing a laminated packaging material comprising at least a base material, an outermost thermoplastic material layer and an innermost low-density polyethylene layer, a method for producing a laminated packaging material comprising a base material and a polyethylene innermost seal layer having a lower density than the innermost seal layer The provision of a high polyethylene interlayer film delays the sorption and diffusion of flavor components such as d-limonene. Furthermore, by depositing metal such as aluminum and tin on the film, Has the effect of improving fragrance retention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail.

(Embodiment 1)

This is a packaging material having the following structure, which comprises a paperboard as a base material, a low-density polyethylene (LDPE) as an innermost layer, and a high-density polyethylene (HDPE) between the substrate and the innermost layer.

LDPE substrate ZHDPEZLDPE

(Embodiment 2)

The innermost layer is made of linear low-density polyethylene (LLDPE) polymerized using a meta-mouth catalyst, with a paperboard substrate, and a polyethylene (higher density) than the innermost layer polyethylene between the substrate and the innermost layer. HDPE) is used.

LDPE substrate ZHDPE / 1LDPE

The above configuration can be manufactured by co-extrusion lamination.

When producing the packaging material of the present invention, the low-density polyethylene used as the innermost layer in the production of the gable-top packaging material by extrusion processing has a density of 0.910—0.926 g / cm ³ and a melting point of 105—. 1 13 ° C. In the case of linear low-density polyethylene, the density is 0.910-0.918 g / cm ³ and the melting point is 102 105 ° C. In the embodiment of the present invention, polyethylene having a density higher than that of the innermost layer has a density of 0.936 g / cm ³ or more and a melting point of 127 or more. They are more than 0.010 g / cm ^{3 in} density than the innermost resin, and Its melting point is over 15 higher. The melting point of the polyethylene resin shown here is the temperature obtained by DSC analysis in accordance with K6922-2.

(Embodiment 3)

In the present invention, the following structure is also one of the embodiments of the present invention.

LDPE substrate / LDPEZHDPE / 1DPE or LLDPE

The material having the above constitution is manufactured by multi-layer extrusion lamination of HDPE or extrusion lamination using HDPE film.

In the method of manufacturing a packaging material using extrusion lamination using an HDPE film, the use of an HDPE film on which a metal such as aluminum or tin is vapor-deposited can further improve the fragrance retention performance. The resulting packaging material has the following layer configuration:

LDPEZ substrate ZLDPEZ metal deposition HDPEZLDPE or LLDPE

In addition, it is preferable that the vapor-deposited HDPE be laminated with the vapor-deposited surface facing the sealant layer during lamination, from the viewpoint of fragrance retention. In practice, there is no problem even if the deposition surface is directed toward the substrate.

In the above description, the configuration example is described, but other materials can be similarly implemented.

After the above-mentioned packaging material is manufactured, it is processed into gable-top blanks by, for example, the same method as that for manufacturing a general gable-top container. In this configuration, when a vapor-deposited HDPE film is used, the metal cross-section (vapor-deposited surface) is exposed. When blanking, cross-section processing such as skiving is performed as necessary.

The packaging container according to the present invention is, for example, a gable-top type container, a brick shape (Parallel hexahedron), hexagonal prism, octagonal prism, tetrahedron, etc.

Example

Next, specific examples of the present invention will be described.

(Example 1)

A packaging material having the following configuration was produced by co-extrusion.

LDPE (16 g / m ² ) / base material HDPE (16 g / m ² ) / LDPE (20 g / m ² ) For the innermost layer and the outermost layer, low-density polyethylene having a density of 0.924 g / cm ³ and a melting point of 113 was used. High density polyethylene having a density of 0.942 g / cm ³ and a melting point of 13 (TC) was used between the base material and the innermost layer.

(Example 2)

LDPE (16 g / m ² ) / base material ZHDPE (16 g / m ² ) / LLDPE (20 g / m ² ) For the outer layer, low-density polyethylene having a density of 0.924 g / cm ³ and a melting point of 113 was used. A high-density polyethylene having a density of 0.942 g / cm ³ and a melting point of 130 was used between the base material and the innermost layer. For the innermost layer, a linear low-density polyethylene having a density of 0.913 g / cm ³ and a melting point of 103 ° C., which was polymerized by a meta-mouth catalyst, was used.

(Example 3)

A 10-m-thick HDPE film was extruded and laminated to produce a packaging material with the following composition.

LDPE (16 g / m ² ) Base material LDPE (10 g / m ² ) / HDPE film (10 m) LDPE (0g / m ²⁾

For the innermost layer, the film laminate layer and the outer layer, low-density polyethylene having a density of 0.924 g / cm ³ and a melting point of 113 was used. The HDPE film used at this time was produced by inflation processing of a high-density polyethylene resin with a density of 0.956 g / cm ³ and a melting point of 131 ° C.

(Example 4)

An aluminum vapor-deposited lO Aim HDPE film was extruded and laminated to produce a packaging material having the following composition.

LDPE (16 g / m ² ) Base material LDPE (10 g / m ² ) Evaporated HDPE film (10 m) Z LDPE (20 g / m ² )

For the innermost layer, film laminate layer and outer layer, low-density polyethylene having a density of 0.924 g / cm ³ and a melting point of 113 ° C was used. The deposited HDPE film is obtained by vacuum-depositing 400 angstroms of aluminum on an HDPE film produced by inflation of a high-density polyethylene resin having a density of 0.956 g / cm ³ and a melting point of 131 ° C.

(Comparative Example 1)

LDPE (16 g / m ² ) base material / LDPE (16 g / m ² ) / LDPE (20 g / m ² )

The same polyethylene was used for the outer layer, the inner layer, and the innermost layer. The density of the low density polyethylene used is 0.924 g / cm ³ and the melting point is 113 ° C. (Comparative Example 2)

Made by co-extrusion of packaging material with the following composition _c

LDPE (16 g / m ² ) / base material ZLDPE (16 g / m ² ) / LLDPE (20 g / m ² ) Outer and inner layers have the same density as Comparative Example 1, 0.924 g / cm ³ , and low melting point of 13 ° C High-density polyethylene was used. For the innermost layer, a linear low-density polyethylene having a density of 0.913 g / cm ³ and a melting point of 103 ° C., which was synthesized using a meta-mouth catalyst, was used.

(Results of fragrance retention comparison test)

1 liter gable top type container blanks were manufactured from the laminates shown in the above Examples and Comparative Examples, and filled with 100% concentrated and reduced orange juice using a filling machine. After the container was left in a 10 ° C atmosphere for 1 day, the fragrance retention was evaluated by a sensory test.

In the evaluation, the orange juice was packed in a glass bottle and sealed, and each fragrance was evaluated by the one-pair comparison method.

The results are shown below. The results are shown as the average of the scores of panelists who rated the intensity of the orange juice flavor of each paper container relative to the five levels of 1, 2, 3, 4, and 5, assuming that the flavor of the orange juice filled in the glass bottle was 5. Was.

5.0

Example 1 3.2

Example 2 3.0

Example 3 3.4

Example 4 3.7 Comparative Example 1 2.2

Comparative Example 2 1.5

Compared to glass bottles, which are considered to have virtually no sorption of flavor components, a reduction in flavor in paper containers is inevitable, but the flavor in the containers of the examples is clearly stronger than that of the comparative examples, It can be determined that all of the packaging materials of the examples have improved fragrance retention.

(Results of heat sealability comparison test)

As in the test for the scent retention, the bottom surface heat sealability was evaluated for the containers obtained using the packaging materials of Comparative Examples and Examples.

The bottom heat sealability of the container of the example was superior to the bottom heat sealability of the container of the comparative example.

As described above, the packaging material of the present invention, the packaging container and the method of manufacturing the packaging material have a flavor retention property such that d-limonene does not escape from the container, while using a general-purpose inexpensive resin, A method for producing a packaging material, a packaging container, and a packaging material having excellent heat sealing properties can be provided. Industrial applicability

INDUSTRIAL APPLICABILITY The packaging material, the packaging container, and the method for producing the packaging material of the present invention are used for a packaging container for storing liquid foods such as milk and soft drinks.

Claims

The scope of the claims

1. A laminated packaging material comprising at least a substrate, an outermost thermoplastic material layer, and an innermost thermoplastic material layer, wherein at least one intermediate layer is provided between the substrate and the innermost layer; A packaging material, wherein the inner layer and the intermediate layer are made of polyethylene resin, and the density of the polyethylene resin in the intermediate layer is higher than the density of the polyethylene resin in the innermost layer.

2. A laminated packaging material comprising at least a base material, an outermost polyethylene layer, an innermost polyethylene layer, and at least one intermediate layer provided between the base material and the innermost layer. A packaging container, wherein the density of polyethylene in the innermost layer and the intermediate layer increases continuously or discontinuously from the inside to the outside.

3. A method for producing a laminated packaging material comprising at least a substrate, an outermost thermoplastic material layer and an innermost thermoplastic material layer, wherein at least one intermediate layer is extruded between the substrate and the innermost layer. The innermost layer and the intermediate layer are made of polyethylene resin, the density of the polyethylene resin of the intermediate layer is higher than the density of the polyethylene resin of the innermost layer, and a metal deposition film is formed on the film of the intermediate layer. A method for producing a packaging material, which is characterized in that: