JP-7854777-B2 - Laminates and packaging containers

Inventors

• 山田 憲一

Assignees

• 大日本印刷株式会社

Dates

Publication Date

20260507

Application Date

20200331

Claims (11)

1. A laminate comprising at least a substrate, a vapor-deposited film, and a sealant layer, The substrate comprises at least a polyethylene resin layer and a surface resin layer, The sealant layer is made of polyethylene resin, The surface resin layer of the substrate contains a resin material with a melting point of 150°C or higher. The vapor-deposited film is provided on the surface resin layer of the substrate , A barrier coating layer is further provided on the aforementioned vapor-deposited film. The aforementioned substrate is a co-extruded film, The polyethylene resin layer is provided with a density gradient. The aforementioned substrate is characterized by being subjected to a stretching treatment, thereby forming a laminate.
2. The laminate according to claim 1, wherein the surface resin layer comprises a resin material having a melting point of 150°C or higher and 265°C or lower.
3. The laminate according to claim 1 or 2, wherein the difference in melting points between the polyethylene resin and the resin material with a melting point of 150°C or higher contained in the surface resin layer is 20 to 80°C.
4. The laminate according to any one of claims 1 to 3, wherein the resin material of the surface resin layer is a polymer having polar groups.
5. The laminate according to any one of claims 1 to 4, wherein the resin material of the surface resin layer is one or more resin materials selected from ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyester, nylon 6, nylon 6,6, nylon 6-nylon 6,6 copolymer, MXD nylon, and amorphous nylon.
6. The laminate according to any one of claims 1 to 5, wherein the polyethylene resin layer of the base material has a multilayer structure.
7. The laminate according to any one of claims 1 to 6, wherein the polyethylene resin layer of the substrate comprises at least one layer containing a compatibilizer.
8. A laminate according to any one of claims 1 to 7 , used in a packaging container.
9. The laminate according to any one of claims 1 to 8 , wherein the polyethylene resin content in the entire laminate is 80% by mass or more.
10. A packaging container comprising a laminate according to any one of claims 1 to 9 .
11. The packaging container according to claim 10 , which is a packaging bag.

Description

This invention relates to a laminate and a packaging container comprising the laminate. Conventionally, resin films made from polyester resins such as polyethylene terephthalate (hereinafter also referred to as polyester films) have been used in the manufacture of packaging containers because they have excellent mechanical properties, chemical stability, heat resistance, and transparency, as well as being inexpensive. Such polyester films are used as a base material and are typically laminated with a polyethylene film, which serves as a sealant layer, to form a laminate that is then molded into a packaging container. The packaging containers obtained by forming laminates of different types of resin films, namely polyester film and polyethylene film, are difficult to separate into their individual layers. Therefore, these used packaging containers are not suitable for recycling and are not actively recycled. In light of this situation, and with the aim of improving the recyclability of packaging containers, the use of stretched polyethylene film (stretched polyethylene film) as the base material instead of polyester film, and the production of packaging containers using laminates composed of the same material (monomaterial packaging containers) are being considered. Japanese Patent Application Publication No. 2005-053223 This is a schematic cross-sectional view showing one embodiment of the laminate of the present invention.This is a schematic cross-sectional view showing one embodiment of the laminate of the present invention.This is a schematic cross-sectional view showing one embodiment of a vapor deposition apparatus.This is a schematic cross-sectional view showing one embodiment of a vapor deposition apparatus.This is a front view showing one embodiment of the packaging container of the present invention.This is a perspective view showing one embodiment of the packaging container of the present invention.This is a front view showing one embodiment of the packaging container of the present invention.This is a cross-sectional view taken along line a-a in Figure 7. (Laminate) As shown in Figure 1, the laminate 10 of the present invention comprises a base material 11, a vapor-deposited film 12, and a sealant layer 13, the base material 11 comprising a polyethylene resin layer 14 and a surface resin layer 15. The polyethylene resin layer of the substrate and the sealant layer of the laminate are composed of the same resin, i.e., polyethylene resin, and a laminate having such a configuration can be suitably used as a laminate for manufacturing monomaterial packaging containers. Furthermore, the laminate of the present invention exhibits significantly improved interlayer adhesion between the substrate and the vapor-deposited film, resulting in extremely high gas barrier properties. The polyethylene resin content relative to the total amount of solids in the laminate is preferably 80% by mass or more, and more preferably 90% by mass or more. This allows for a laminate that can be suitably used in the manufacture of monomaterial packaging containers. Furthermore, in one embodiment, the base material 11 may further include an adhesive resin layer 16 between the polyethylene resin layer 14 and the surface resin layer 15, as shown in Figure 2. Furthermore, in one embodiment, the laminate 10 of the present invention includes a barrier coat layer between the vapor-deposited film 12 and the sealant layer 13 (not shown). The following describes each layer of the laminate of the present invention. (Base material) The substrate comprises at least a polyethylene resin layer and a surface resin layer. In one embodiment, the substrate also comprises an adhesive resin layer between the polyethylene resin layer and the surface resin layer. The ratio of the thickness of the surface resin layer to the total thickness of the substrate is preferably 2% to 20%, and more preferably 4% to 15%. By setting the ratio of the surface resin layer thickness to the total thickness of the substrate to 2% or more, the adhesion of the vapor-deposited film can be further improved, and the gas barrier properties can be further enhanced. Furthermore, by setting the ratio of the surface resin layer thickness to the total thickness of the base material to 20% or less, a laminate suitable for use in the production of monomaterial packaging containers can be created. In addition, the film-forming properties and processability of the base material can be further improved. (Polyethylene resin layer) The polyethylene resin layer is made of polyethylene resin. As the polyethylene resin, high-density polyethylene resin (HDPE), medium-density polyethylene resin (MDPE), low-density polyethylene resin (LDPE), linear low-density polyethylene resin (LLDPE), and very low-density polyethylene resin (VLDPE) can be used. Furthermore, a copolymer of ethylene and other monomers can also be used as the polyethylene resin. Furthermore, as polyethylene resin, biomass-d