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JP-7854784-B2 - packaging material

JP7854784B2JP 7854784 B2JP7854784 B2JP 7854784B2JP-7854784-B2

Inventors

  • 中村 淳
  • 伊賀 巨訓
  • 鳥山 香奈子
  • 高田 秀樹
  • 浦崎 淳

Assignees

  • 三菱製紙株式会社

Dates

Publication Date
20260507
Application Date
20210216

Claims (4)

  1. A packaging material comprising a paper support and one or more coating layers on one side of the paper support, wherein the paper support has a density of 0.83 g/ cm³ to 1.03 g/ cm³ and an ash content of 2.3% by mass or less, the outermost coating layer located on the outermost side relative to the paper support contains at least an ionomer resin of an ethylene unsaturated carboxylic acid copolymer , and the opacity of the paper support is 70% to 85% .
  2. The packaging material according to claim 1, wherein the inorganic pigment content is 2% by mass or less relative to the dry solid content of the outermost coating layer.
  3. The packaging material according to claim 1 or 2, wherein the coating layer, including the outermost coating layer, is a single layer.
  4. The packaging material according to claim 1 or 2, wherein the ionomer resin of an ethylene unsaturated carboxylic acid copolymer accounts for 90% by mass or more of the dry solid content of the outermost coating layer.

Description

This invention relates to a heat-sealable packaging material made of a paper support, and more particularly to a packaging material used in a secondary packaging body in the form of a bag. Food products such as confectionery displayed in retail stores often consist of packaging that includes a primary packaging containing the food product and a secondary packaging containing one or more of the primary packaging units. Typically, primary packaging exists to protect food, and secondary packaging exists to protect the primary packaging. Secondary packaging comes in two forms: bags and boxes. Bag-type secondary packaging is generally created by covering the primary packaging with packaging material and heat-sealing the edges of the packaging material. Therefore, the packaging material used for bag-type secondary packaging must be suitable for heat sealing. Packaging materials suitable for heat sealing are known. For example, there is a known packaging paper having at least one heat-seal layer on at least one surface of a paper substrate, wherein the heat-seal layer contains an ionomer and the dry coating amount of the heat-seal layer is 2 to 10 g/ m² for the entire layer (see, for example, Patent Document 1). Japanese Patent Publication No. 2020-117311 The packaging material comprises a paper support and one or more coating layers on one side of the paper support. In the coating layers, the outermost coating layer relative to the paper support is called the outermost coating layer. If there is only one coating layer, this is the outermost coating layer. If there are two or more coating layers, the coating layers between the base paper and the outermost coating layer are not particularly limited. In some embodiments, the coating layers between the base paper and the outermost coating layer are provided to impart various functions to the packaging material as needed. Examples of coating layers include a gas barrier layer containing a gas barrier agent, a water vapor barrier layer containing a water vapor barrier agent, an oil barrier layer containing an oil resistant agent, and an insulating layer containing an insulating material. In some embodiments, for packaging materials used in secondary packaging, there is only one coating layer, including the outermost coating layer. That is, there is only one coating layer. This is because it results in a more cost-effective manufacturing process for packaging materials used in secondary packaging. Furthermore, the coating layer may be present on one or both sides of the paper support. In some embodiments, the packaging material has the outermost coating layer on only one side of the paper support. In some embodiments, in packaging materials where the outermost coating layer is present on only one side of the paper support, a conventionally known printing coating layer or backcoat layer is provided on the opposite side of the paper support for the purpose of improving printability or dimensional stability. For packaging materials used in secondary packaging, the side of the packaging material facing the contents is the side of the packaging material that has the outermost coating layer. The paper support is a base paper produced by conventionally known papermaking methods under acidic, neutral, or alkaline conditions, using a pulp basil prepared by adding various additives such as fillers, internal sizing agents, fixatives, yield agents, and paper strength agents as needed to a slurry of wood pulp and/or non-wood pulp; a base paper prepared by calendering the said base paper; a fine paper prepared by sizing the said base paper with a sizing liquid containing a surface sizing agent; or a fine paper prepared by calendering the said fine paper. The above-mentioned paper pulp may be appropriately supplemented with one or more additives selected from the following: pigment dispersants, binders, thickeners, fluidity improvers, bulking agents, defoaming agents, antifoaming agents, mold release agents, foaming agents, penetrating agents, coloring dyes, coloring pigments, fluorescent whitening agents, ultraviolet absorbers, antioxidants, preservatives, anti-fungal agents, water-resistant agents, etc., within a range that does not impair the desired effects of the present invention. Calendaring is a process that equalizes the smoothness and thickness of paper by passing it between rolls. Examples of calendaring equipment include machine calendars, soft nip calendars, supercalenders, multi-stage calendars, and multi-nip calendars. Size pressing is a process that imparts water resistance to the surface of paper. Size pressing is performed using size pressing equipment conventionally known in the papermaking field. Examples of size pressing equipment include inclined size presses, horizontal size presses, and film transfer equipment such as rod metering size presses, roll metering size presses, and blade metering size presses. Examples of rod metering size presses include shimsizers,