EP-4741159-A1 - PACKAGING FILM, PACKAGING CONTAINER, AND PACKAGING PRODUCT

Abstract

A packaging film includes a gas barrier film, an adhesive layer, and a sealant layer in this order. The gas barrier film includes a substrate layer, an anchor coat layer, and a vapor deposition layer in this order, the substrate layer includes a polyolefin substrate layer containing a polyolefin-based resin, the anchor coat layer contains a polyurethane resin, and the anchor coat layer has a thickness of 0.02 µm or more. The adhesive layer is obtained by bonding an adhesive resin composition containing a polyolefin 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 (8)

1. A packaging film comprising a gas barrier film, an adhesive layer, and a sealant layer in this order, wherein the gas barrier film includes a substrate layer, an anchor coat layer, and a vapor deposition layer in this order; the substrate layer includes a polyolefin substrate layer containing a polyolefin-based resin; the anchor coat layer contains a polyurethane resin; the anchor coat layer has a thickness of 0.02 µm or more; the adhesive layer is obtained by bonding an adhesive resin composition containing a polyolefin adhesive resin to the gas barrier film by melt extrusion; and the sealant layer contains a polyolefin-based resin.
2. The packaging film according to claim 1, wherein the anchor coat layer has a thickness of 0.2 µm or more.
3. The packaging film according to claim 1, wherein the anchor coat layer has a thickness of less than 2.5 µm.
4. The packaging film according to claim 3, wherein the anchor coat layer has a thickness of 2.0 µm or less.
5. The packaging film according to claim 1, wherein the polyolefin substrate layer is a stretched film.
6. 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 to cover the vapor deposition layer.
7. A packaging container comprising the packaging film according to any one of claims 1 to 6.
8. A packaged product comprising the packaging container according to claim 7, and contents filled 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 mono-materials to facilitate material recycling. On the other hand, packaging materials 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 substrate layer containing a polyolefin-based resin and a polyolefin sealant layer containing a polyolefin-based resin, with these layers bonded together by dry lamination using an adhesive forming a non-polyolefin-based resin. However, such packaging films, which use adhesives forming non-polyolefin-based resins, may deteriorate the quality of the recycled resins obtained from 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 adhesive resin such as maleic anhydride graft-polymerized polypropylene, in place of an adhesive forming a non-polyolefin-based resin (see PTL 1 below). [Citation List] [Patent Literature] PTL 1: JP2020049679A [Summary of the Invention] [Technical Problem] However, although the laminate described in PTL 1 can increase the ratio of polyolefin-based resins in the entire laminate, there is still room for improvement in terms of gas barrier properties. The present disclosure has been made in light of the issues mentioned above and aims to provide a packaging film which can suppress decrease in the ratio of polyolefin-based resins in the entire packaging film, while exhibiting excellent gas barrier properties, and to provide a packaging container and a packaged product. [Solution to Problems] In order to solve the above issues, an aspect of the present disclosure provides a packaging film including a gas barrier film, an adhesive layer, and a sealant layer in this order, wherein the gas barrier film includes a substrate layer, an anchor coat layer, and a vapor deposition layer in this order; the substrate layer includes a polyolefin substrate layer containing a polyolefin-based resin; the anchor coat layer contains a polyurethane resin; the anchor coat layer has a thickness of 0.02 µm or more; the adhesive layer is obtained by bonding an adhesive resin composition containing a polyolefin 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, decrease in the ratio of polyolefin-based resins in the entire packaging film can be suppressed, while exhibiting excellent gas barrier properties. The inventors of the present disclosure presume that the reasons for the above effect are as follows. Specifically, when the adhesive resin composition containing a polyolefin adhesive resin is bonded to the gas barrier film by melt extrusion, heat of the adhesive resin composition may be transferred to the substrate layer via the vapor deposition layer. The polyolefin adhesive resin composition is at a high temperature when it comes into contact with the gas barrier film, but is then cooled by a cooling roll to a low temperature. Accordingly, even when the polyolefin substrate layer expands and then contracts, the anchor coat layer containing a polyurethane resin may effectively mitigate the expansion and contraction stresses transmitted from the substrate layer to the vapor deposition layer, thereby suppressing expansion and contraction of the fragile vapor deposition layer. Consequently, the packaging film may be able to have excellent gas barrier properties. Furthermore, the anchor coat layer having a thickness of 0.02 µm or more, even though it is thin, may be able to effectively suppress expansion and contraction of the polyolefin substrate layer. Therefore, decrease in the ratio of polyolefin-based resins in the entire packaging film can be suppressed. In the packaging film, the anchor coat layer preferably has a thickness of 2.0 µm or less. In this case, decrease in the ratio of polyolefin-based resins in the entire packaging film can be further suppressed. In the packaging film, the polyolefin substrate layer is preferably a stretched film. In this case, crystallinity of the polyolefin substrate layer included in the substrate layer is improved to raise the melting point, and therefore the difference in melting point between the sealant layer and the substrate layer can be increased, and thus melting of the substrate layer can be easily suppressed when heat-sealing the packaging film. In the packaging film, the gas barrier film preferably further includes a coating layer between the vapor deposition layer and the adhesive layer to cover the vapor deposition layer. In this case, when the adhesive resin com