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US-12624438-B2 - Gas barrier laminate, packaging member, packaging bag, and tubular container

US12624438B2US 12624438 B2US12624438 B2US 12624438B2US-12624438-B2

Abstract

A gas barrier laminate including: a substrate layer which contains a polyolefin resin; a metal oxide-containing layer which contains a metal oxide; and an overcoat layer which contains a polyvinyl alcohol resin, the overcoat layer having a surface, the overcoat layer having a surface which has a softening temperature of 100 to 170° C., as measured by local thermal analysis.

Inventors

  • Ayumi Tanaka
  • Mikinori YAMADA
  • Takeshi Nishikawa
  • Miki Fukugami

Assignees

  • TOPPAN INC.

Dates

Publication Date
20260512
Application Date
20230227
Priority Date
20200831

Claims (17)

  1. 1 . A gas barrier laminate, comprising: a substrate layer which contains a polyolefin resin; a metal oxide-containing layer which contains a metal oxide; and an overcoat layer which contains a polyvinyl alcohol resin and a polyurethane resin, a mass ratio between the polyurethane resin and the polyvinyl alcohol resin being 0.9 to 1.2, the overcoat layer having a surface which has a softening temperature of 130 to 170° C., as measured by local thermal analysis.
  2. 2 . The gas barrier laminate of claim 1 , wherein the metal oxide-containing layer is made of a vacuum deposition layer and has a thickness of 5 to 100 nm.
  3. 3 . The gas barrier laminate of claim 1 , wherein the overcoat layer contains Si.
  4. 4 . The gas barrier laminate of claim 1 , further comprising an anchor coat layer between the substrate layer and the metal oxide-containing layer.
  5. 5 . The gas barrier laminate of claim 1 , wherein the overcoat layer has a thickness of 100 to 800 nm.
  6. 6 . The gas barrier laminate of claim 1 , wherein the softening temperature of the surface of the overcoat layer is from 130 to 140° C.
  7. 7 . The gas barrier laminate of claim 1 , wherein the overcoat layer is prepared by coating a coating liquid, wherein solids in the coating liquid consists of the polyurethane resin, the polyvinyl alcohol resin and optionally, a silane coupling agent.
  8. 8 . The gas barrier laminate of claim 1 , wherein wherein the mass ratio between the polyurethane resin and the polyvinyl alcohol resin is 50:50.
  9. 9 . The gas barrier laminate of claim 1 , wherein the overcoat layer further comprises a silane coupling agent, and wherein a mass ratio between the polyurethane resin, the polyvinyl alcohol resin and the silane coupling agent is 50:45:5.
  10. 10 . The gas barrier laminate of claim 1 , wherein the overcoat layer is prepared by coating a coating liquid, wherein solids in the coating liquid consists of the polyurethane resin and the polyvinyl alcohol resin.
  11. 11 . The gas barrier laminate of claim 10 , wherein the mass ratio between the polyurethane resin and the polyvinyl alcohol resin is 50:50.
  12. 12 . The gas barrier laminate of claim 1 , wherein the overcoat layer is prepared by coating a coating liquid, wherein solids in the coating liquid consists of the polyurethane resin, the polyvinyl alcohol resin and a silane coupling agent.
  13. 13 . The gas barrier laminate of claim 12 , wherein the silane coupling agent is 3-glycosidoxypropyltriethoxysilane.
  14. 14 . The gas barrier laminate of claim 12 , wherein a mass ratio between the polyurethane resin, the polyvinyl alcohol resin and the silane coupling agent is 50:45:5.
  15. 15 . A packaging member, comprising: the gas barrier laminate of claim 1 ; and a sealant layer.
  16. 16 . A packaging bag comprising the packaging member of claim 15 .
  17. 17 . A tubular container comprising the packaging member of claim 15 .

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS This application is a continuation application filed under 35 U.S.C. § 111(a) claiming the benefit under 35 U.S.C. §§ 120 and 365(c) of International Patent Application No. PCT/JP2021/023091, filed on Jun. 17, 2021, which in turn claims the benefit of JP 2020-145417, filed Aug. 31, 2020, the disclosures of all which are incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure generally relates to a gas barrier laminate, a packaging member, a packaging bag, and a tubular container. BACKGROUND ART As a packaging material for packaging food, and the like, a gas barrier film, in which a gas barrier layer is laminated on a polyolefin film, is known (for example, PTL 1). CITATION LIST Patent Literature PTL 1: JP 2005-335273 A. SUMMARY OF THE INVENTION Technical Problem In the past, barrier films generally used heat-resistant base materials such as polyester film or nylon film, which were further bonded to polypropylene or polyethylene to produce bags. The recent trend toward mono-materials has led to attempts to use polyolefin-based substrates such as polypropylene and polyethylene, as shown in PTL 1. However, if a polyolefin-based resin such as polypropylene or polyethylene is used as a substrate in the same manner as polyester film or nylon film, resistance to heat sterilization treatment (hot water treatment) such as boiling and resistance to bending may be insufficient. The present disclosure has been made in view of the above circumstances, and the purpose of the present disclosure is to provide a gas barrier laminate capable of achieving good hot water resistance and bending resistance using a polyolefin substrate. The disclosure is also intended to provide a packaging material including the gas barrier laminate, a packaging bag, and a tubular container. Solution to Problem As a result of intensive studies, the inventors have found that adjusting the softening temperature of the surface of the overcoat layer to a predetermined range was an important factor in solving the above problem, and thus they completed the gas barrier laminate according to the present disclosure. The present disclosure provides a gas barrier laminate including: a substrate layer which contains a polyolefin resin, a metal oxide-containing layer which contains a metal oxide, and an overcoat layer which contains a polyvinyl alcohol resin, the overcoat layer having a surface which has a softening temperature of 100 to 170° C., as measured by local thermal analysis. In an embodiment, the metal oxide-containing layer may be a vacuum deposition layer, and may have a thickness of 5 to 100 nm. In an embodiment, the overcoat layer may contain Si. In an embodiment, the gas barrier laminate may further comprise an anchor coat layer between the substrate layer and the metal oxide-containing layer. In an embodiment, the overcoat layer may have a thickness of 100 to 800 nm. The present disclosure provides a packaging material comprising the gas barrier laminate and a sealant layer. The present disclosure provides a packaging bag including the packaging material. The present disclosure provides a tubular container including the packaging material. Advantageous Effects of the Invention According to the present disclosure, it is possible to provide a gas barrier laminate that can achieve good hot water resistance and bending resistance using a polyolefin substrate. The disclosure is also intended to provide a packaging material including the gas barrier laminate, a packaging bag, and a tubular container. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view illustrating a gas barrier laminate according to an embodiment. FIG. 2 is a schematic cross-sectional view of a packaging material according to an embodiment. FIG. 3 is a schematic cross-sectional view of a packaging material according to an embodiment. FIG. 4 is a perspective view of a packaging bag according to an embodiment. FIG. 5 is a front view of a tubular container according to an embodiment. DETAILED DESCRIPTION Embodiments of the present invention will be described below with reference to the drawings. In the following description of the drawings to be referred, components or functions identical with or similar to each other are given the same or similar reference signs, unless there is a reason not to. It should be noted that the drawings are only schematically illustrated, and thus the relationship between thickness and two-dimensional size of the components, and the thickness ratio between the layers, are not to scale. Therefore, specific thicknesses and dimensions should be understood in view of the following description. As a matter of course, dimensional relationships or ratios may be different between the drawings. Further, the embodiments described below are merely examples of configurations for embodying the technical idea of the present invention. The technical idea of the prese