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EP-4737640-A1 - COATED PAPER LINER

EP4737640A1EP 4737640 A1EP4737640 A1EP 4737640A1EP-4737640-A1

Abstract

A coated paper liner serves as both exterior packaging and an interior release liner for consumer products. The liner comprises a paper sheet layer with a first polymeric composition, such as a thermoplastic elastomer or polymer, forming a film on at least a portion of a surface of the paper sheet. The liner also comprises a flexibility agent that enhances pliability and noise reduction during handling. The liner may include a release agent, like silicone, to prevent adhesion of consumer products to the liner. The method of manufacturing involves coating the paper sheet with the polymeric composition and flexibility agent, followed by drying. This solution offers a sustainable alternative to plastic films, providing to the liner heat-sealability, barrier properties, and recyclability.

Inventors

  • VALERA, NATACHA
  • Rodiño Lopez, José Antonio
  • Canales Perez, Jorge
  • Urquiola Zaballa, Francisco Borja

Assignees

  • Industrias de Transformacion de Andoain, S.A.U

Dates

Publication Date
20260506
Application Date
20241031

Claims (15)

  1. A coated paper liner comprising: a first layer comprising a paper sheet layer; a first coating comprising a first polymeric composition selected from the group consisting of a thermoplastic elastomer, a thermoplastic polymer, or combinations thereof that forms a film on at least a portion of a surface of the paper sheet layer; and wherein the paper liner further comprises a flexibility agent.
  2. The coated paper liner of claim 1, wherein the paper sheet layer comprises a mixture selected from the group consisting of wood pulp, preferably said wood pulp comprising hardwood and softwood wood fibers; non-wood pulp, preferably said non-wood pulp comprising fibers from a source selected from the group consisting of bamboo, hemp, straw, agricultural residues and combinations thereof; pre and/or post-consumer recycled fibers; and any combinations thereof.
  3. The coated paper liner of any of claim 2, wherein the hardwood pulp comprises eucalyptus and the softwood pulp comprises northern bleached kraft softwood.
  4. The coated paper liner of any of claims 1-3, wherein the paper sheet has a grammage of between 10 -120 g/m 2 , preferably 15-100 g/m 2 , more preferably 20-90 g/m 2 .
  5. The coated paper liner of any of claims 1-4, wherein the first coating comprises a mixed coating of the first polymeric composition and the flexibility agent, wherein an amount of the mixed coating is 0.1 to 10 g/ per m 2 of the paper sheet, preferably 2 to 7 g per m 2 of the paper sheet, more preferably 3 to 5 g per m 2 of the paper sheet.
  6. The coated paper liner of any of claims 1-5, wherein the first polymeric composition and flexibility agent are in a weight ratio of between 50:50 and 95:5, preferably between 60:40 and 90:10, more preferably approximately 85:15.
  7. The coated paper liner of any of claims 1-6, wherein the first coating comprises an amount of first polymeric composition of 0.05-9.0 g per m 2 of paper sheet, preferably 0.60-6.0 g per m 2 of paper sheet, and more preferably 1.5-3.5 g per m 2 of paper sheet.
  8. The coated paper liner of any of claims 1-7, wherein the first coating comprises an amount of flexibility agent of 0.1-5 g per m 2 of paper sheet, preferably 0.15-2.8 g per m 2 of paper sheet, more preferably 0.6-1.5 g per m 2 of paper sheet.
  9. The coated paper liner of any of claims 1-8, wherein the first polymeric composition is a thermoplastic elastomer dispersion, preferably the thermoplastic elastomer dispersion comprises a polymer selected from the group consisting of ethylene C 1-6 alkyl acrylate copolymer, ethylene C 1-6 alkyl acrylic acid copolymer, vinyl acetate-ethylene copolymer, ethylene vinyl acetate, polyvinyl acetate copolymer, polyethylene, and combination thereof; more preferably the thermoplastic elastomer dispersion comprises a blend of ethylene ethyl acrylate and ethylene vinyl acetate.
  10. The coated paper liner of any of claims 1-9, wherein the flexibility agent is selected from the group consisting of a polymeric gelling agent, an oily component, a surfactant, a polyol, and combinations thereof; preferably the flexibility agent is a polyol selected from a group consisting of glycerin, sorbitol, C 1-6 alkylene glycol, xylitol, and combination thereof, more preferably the polyol is glycerin.
  11. The coated paper liner of any of claims 1-10, wherein a heat-sealing force of the paper liner is equal to or greater than 0.30 N, preferably 0.5N, more preferably 0.70N.
  12. The coated paper liner of claims 1-11, further comprising a second coating comprising a release agent that forms a film on at least a portion of a surface of the paper sheet.
  13. The coated paper liner of claim 12, wherein the release agent comprises a silicone selected from the group consisting of addition-curing solventless silicone, addition-curing silicone emulsion, UV-cured silicone, and solvent-based silicone.
  14. The coated paper liner of any of claim 13, wherein the silicone is coated in an amount of 0.1 g to 4 g/m 2 , preferably 0.5 to 1.5 g/ m 2 .
  15. Packaging comprising the coated paper liner of any of claims 1-14.

Description

Technical Field This disclosure pertains to the field of flexible packaging for consumer products. Background Art Individually packaged consumer products are generally wrapped in a protective pouch, bag, envelopes, or the like which may be heat-sealed to enclose and protect the product from external elements such as dirt, moisture, oil, oxygen, or other airborne contaminants. Plastic films have been previously used for such packaging, however, reliance on plastic materials poses environmental concerns, as they generate waste that is difficult to manage and recycle. Additionally, packaging of certain consumer products poses the additional challenge of preventing unintended adhesion or material transfer between the consumer product and the interior of the packaging. In addition, some products are sensitive to humidity, oxygen grease that may penetrate the package and deteriorate the packaged product. Previous attempts to prevent these issues included the use of an intermediate release liner to act as a barrier between the packaging and the product. The addition of a release liner complicates the manufacturing process, increases costs, and increases the amount of waste produced. For cost reduction, packaging simplification, and environmental sustainability, packaging and release liners may be formed as a single packaging solution, eliminating the need for separate release liners and packaging. Previous attempts to produce packaging-release liner combinations have been formed of silicone-coated plastic films. Such films provide sufficient heat-sealability and flexibility, however, they produce solid waste which may not be recyclable. The production and disposal of plastic films have a significant carbon footprint, which further exacerbates environmental issues. There exists a need for a more environmentally sustainable packaging which eliminates the need for plastic film while maintaining proper flexibility, barrier properties, heat-sealability, and in some instances, product releasability. Summary Accordingly, this invention presents a coated paper liner and manufacturing method thereof that addresses the aforementioned challenges. The coated paper liner can be formed into a container, such as a pouch, bag, or envelope, and may serve as both exterior packaging and an interior release liner for consumer products. By coating at least a portion of the paper with a first polymeric composition, a flexibility agent, and optionally, a release agent, such as a non-stick silicone coating, the solution provides a sustainable alternative to traditional plastic films. This approach not only reduces solid waste but also enhances recyclability, offering a more environmentally friendly packaging solution. In general, the invention is carried out by coating at least a portion of a paper sheet with a first polymeric composition, a flexibility agent, and optionally, a non-stick silicone coating. Brief Description of Drawings Fig. 1 is a schematic of an example coated paper liner according to the present invention.Fig. 2 is a schematic of an example coated paper liner according to the present invention.Fig. 3 is a schematic of an example coated paper pouch according to the present invention.Fig. 4 is a schematic of an example coated paper bag according to the present invention.Fig. 5A-D are schematics of example methods of manufacturing a coated paper liner according to the present invention. Description of Embodiments The coated paper liner and any subsequent packaging made therefrom comprise a first layer comprising a paper sheet layer and a first coating of a first polymeric composition selected from the group consisting of thermoplastic elastomer, thermoplastic polymer, or a combination thereof forming a film on a at least a portion of a surface of the paper sheet layer, wherein the coated paper liner further comprises a flexibility agent. In some embodiments, the paper liner may also include a second coating of a release agent forming a film on at least a portion of a surface of the paper sheet layer. The first polymeric composition in some embodiments may act as a heat-sealing layer. Heat-sealing should be understood to refer to a material which forms a bond when subjected to heat and pressure. Such compositions melt and flow upon heating, creating a seal that is both strong and durable. In the context of packaging, the first polymeric composition acting as a heat-sealing layer may provide the necessary adhesion so as to form paper liners that securely enclose products, while also offering barrier properties against moisture, vapor, oxygen and oils. A flexibility agent should be understood to refer a material which imparts increased flexibility to the material onto which it is applied. This results in decreased noise generation by the material and reduced risk of tear or rupture. In the context of the paper liner and any subsequent packaging made therefrom, flexibility agents may be those which are absorbed by the paper sh