EP-4741158-A1 - PACKAGING FILM, PACKAGING CONTAINER, AND PACKAGING PRODUCT

EP4741158A1EP 4741158 A1EP4741158 A1EP 4741158A1EP-4741158-A1

Abstract

A packaging film includes a gas barrier film, an adhesive layer and a sealant layer laminated in this order. The gas barrier film includes a substrate layer and a vapor deposition layer, and the substrate layer includes a polyolefin-based substrate layer containing a polyolefin-based resin, and a heat-resistant layer. The heat-resistant layer contains a high-melting-point resin having a melting point of 180°C or higher, the adhesive layer is obtained by adhering an adhesive resin composition containing a polyolefin-based adhesive resin to the gas barrier film by melt extrusion, and the sealant layer contains a polyolefin-based resin.

Inventors

OTSUKA HIROYUKI
ITO YUTAKA
NISHIHARA TSUGUKI
OCHIAI SHINYA
TOMATSURI TAKEO

Assignees

Toppan Holdings Inc.

Dates

Publication Date: 20260513
Application Date: 20240401

Claims (13)

A packaging film comprising: a gas barrier film; an adhesive layer; and a sealant layer, which are laminated in this order, wherein the gas barrier film includes a substrate layer and a vapor deposition layer, the substrate layer includes a polyolefin-based substrate layer containing a polyolefin-based resin, and a heat-resistant layer, the heat-resistant layer contains a high-melting-point resin having a melting point of 180°C or higher, the adhesive layer is obtained by adhering an adhesive resin composition containing a polyolefin-based adhesive resin to the gas barrier film by melt extrusion, and the sealant layer contains a polyolefin-based resin.
The packaging film according to claim 1, wherein the heat-resistant layer is provided on the vapor deposition layer side of the polyolefin-based substrate layer.
The packaging film according to claim 1, wherein the polyolefin-based substrate layer is a stretched film.
The packaging film according to claim 1, wherein the high-melting-point resin of the heat-resistant layer contains a polyamide resin.
The packaging film according to claim 1, wherein the heat-resistant layer contains a high-melting-point resin having a melting point of 185°C or higher.
The packaging film according to claim 1, wherein a ratio of a thickness of the heat-resistant layer to a thickness of the gas barrier film is 50% or less.
The packaging film according to claim 1, wherein the gas barrier film further includes an anchor coat layer between the vapor deposition layer and the substrate layer, the anchor coat layer containing a polyurethane resin.
The packaging film according to claim 1, wherein the gas barrier film further includes a coating layer between the vapor deposition layer and the adhesive layer, the coating layer covering the vapor deposition layer.
The packaging film according to claim 8, wherein the polyolefin-based resin is a polypropylene-based resin, the coating layer covers the vapor deposition layer and has a hardness of 0.4 GPa or greater in a cross-section, and a ratio of a thickness of the heat-resistant layer to a thickness of the gas barrier film is 5% or greater and 50% or less.
The packaging film according to claim 9, wherein the coating layer has a hardness of 0.8 GPa or greater in a cross-section.
The packaging film according to claim 1, wherein the polyolefin-based resin is a polyethylene-based resin, and a ratio of a thickness of the heat-resistant layer to a thickness of the gas barrier film is 5% or greater and 50% or less.
A packaging container comprising the packaging film according to any one of claims 1 to 11.
A packaged product comprising: the packaging container according to claim 12; and contents contained in the packaging container.

Description

[Technical Field] The present disclosure relates to packaging films, packaging containers and packaged products. [Background Art] In recent years, packaging films are increasingly being made from monomaterials to facilitate material recycling. On the other hand, packaging films are also required to maintain functions such as gas barrier properties. In contrast, packaging films are under consideration which include a gas barrier film, which is formed by providing a gas barrier layer by vapor deposition on a polyolefin-based substrate layer containing a polyolefin-based resin, and a polyolefin-based sealant layer containing a polyolefin-based resin, bonded together by dry lamination using an adhesive that may form a non-polyolefin-based resin. However, in such packaging films, the use of an adhesive that can form a non-polyolefin-based resin may reduce the quality of recycled resins obtained by material recycling of the packaging films. Therefore, in order to suppress deterioration of the quality of recycled resins, laminates are known which use, as an adhesive layer, an adhesive resin composition containing a polyolefin-based adhesive resin such as maleic anhydride graft-polymerized polypropylene, instead of an adhesive that can form a non-polyolefin-based resin (see PTL 1 below). [Citation List] [Patent Literature] PTL 1: JP 2020-049679 A [Summary of Invention] [Technical Problem] Although the laminate described in PTL 1 can increase the ratio of the polyolefin-based resin to the entire laminate, there is still room for improvement in terms of gas barrier properties. The present disclosure has been made in view of the above issues, and aims to provide a packaging film, a packaging container and a packaged product having excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin-based resin to the entire packaging film. [Solution to Problem] In order to solve the above problems, an aspect of the present disclosure provides a packaging film including: a gas barrier film; an adhesive layer; and a sealant layer, which are laminated in this order, wherein the gas barrier film includes a substrate layer and a vapor deposition layer, the substrate layer includes a polyolefin-based substrate layer containing a polyolefin-based resin, and a heat-resistant layer, the heat-resistant layer contains a high-melting-point resin having a melting point of 180°C or higher, the adhesive layer is obtained by adhering an adhesive resin composition containing a polyolefin-based adhesive resin to the gas barrier film by melt extrusion, and the sealant layer contains a polyolefin-based resin. According to the above packaging film, it is possible to provide excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin-based resin to the entire packaging film. The inventors of the present disclosure presume that the reasons for the above effect are as follows. That is, when an adhesive resin composition containing a polyolefin-based adhesive resin is adhered to a gas barrier film by melt extrusion, the heat from the adhesive resin composition is transferred to a substrate layer via a vapor deposition layer. The polyolefin-based adhesive resin composition is at a high temperature when it comes into contact with the gas barrier film, but it is subsequently cooled by a cooling roll and becomes low temperature. This may cause the polyolefin-based substrate layer to expand and then contract. Here, since the heat-resistant layer in the substrate layer contains a high-melting-point resin having a melting point of 180°C or higher, it suppresses thermal expansion of the polyolefin-based substrate layer and also suppresses contraction due to cooling, and as a result, stretching and shrinking of the vapor deposition layer, which is prone to cracking, can be suppressed. Therefore, it is possible to provide the packaging film with excellent gas barrier properties. Further, since the substrate layer includes a heat-resistant layer in addition to the polyolefin-based substrate layer, and the heat-resistant layer contains a high-melting-point resin having a melting point of 180°C or higher, the substrate layer, even if it is thin, can suppress expansion and contraction of the polyolefin-based substrate layer. Therefore, it is possible to suppress a decrease in the ratio of the polyolefin-based resin to the entire packaging film. In the above packaging film, the heat-resistant layer is preferably provided on the vapor deposition layer side of the polyolefin-based substrate layer. In this case, since the heat-resistant layer is disposed between the vapor deposition layer and the polyolefin-based substrate layer, even if the polyolefin-based substrate layer tends to expand and contract after the adhesive resin composition is adhered to the gas barrier film by melt extrusion to form the adhesive layer, expansion and contraction of the heat-resistant layer is sufficiently suppressed, and t