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EP-4735250-A1 - PACKAGING MATERIAL

EP4735250A1EP 4735250 A1EP4735250 A1EP 4735250A1EP-4735250-A1

Abstract

A multi-layer packaging material comprising - a polymeric substrate comprising or consisting of a polymeric component selected from the group consisting of a polyhydroxyalkanoate polymer or copolymer, polybutylene succinate or its copolymers, polylactic acid, polybutylene adipate terephthalate and mixtures thereof, and - a barrier coating layer on one or both sides of the substrate comprising: from 51 to 99 % wt, preferably 90 - 99 % wt, more preferably 95 - 98 % wt. of a polymeric component selected from the group consisting of a polyhydroxyalkanoate polymer or copolymer, proteins from milk or legumes, polylactic acid, polybutylene succinate or its copolymers, starch, chitosan, carrageenan, pectin, alginates, lipids, polyacrylic polymers, polyurethane, cellulose or chemically modified cellulose and mixtures thereof, and from 49 to 1 % wt, preferably 1-10 % wt, more preferably 2-5 % wt. of a filler selected from the group consisting of a layered double hydroxide, nanocellulose, silicates, clay and mixtures thereof, the percentages by weight being referred to 100 parts by weight of the polymeric component and the filler.

Inventors

  • ZULIANI, Luca
  • ROMANO, Igor

Assignees

  • SOREMARTEC S.A.

Dates

Publication Date
20260506
Application Date
20240627

Claims (18)

  1. 1. A multi-layer packaging material comprising - a polymeric substrate comprising or consisting of a polymeric component selected from the group consisting of a polyhydroxyalkanoate polymer or copolymer, polybutylene succinate or its copolymers, polylactic acid, polybutylene adipate terephthalate and mixtures thereof, and - a barrier coating layer on one or both sides of the substrate comprising: from 51 to 99 % wt., preferably 90 - 99 % wt., more preferably 95 - 98 % wt. of a polymeric component selected from the group consisting of a polyhydroxyalkanoate polymer or copolymer, proteins from milk or legumes, polylactic acid, polybutylene succinate or its copolymers, starch, chitosan, carrageenan, pectin, alginates, lipids, polyacrylic polymers, polyurethane, cellulose or chemically modified cellulose and mixtures thereof, and from 49 to 1 % wt., preferably 1-10 % wt., more preferably 2-5 % wt. of a filler selected from the group consisting of a layered double hydroxide, nanocellulose, silicates, clay and mixtures thereof, the percentages by weight being referred to 100 parts by weight of the polymeric component and the filler.
  2. 2. The multi-layer packaging material of claim 1 wherein said polyhydroxyalkanoates (PHAs)for the substrate or for the barrier layer include medium chain length PHAs with 6- 14 carbon atoms in their monomer units, with melting points, typically from 50 to 170°, preferably from 100 to 160°.
  3. 3. The multi-layer packaging material of claim 1 or 2, wherein said polyhydroxyalkanoate of the substrate or of the barrier coating is selected from the group consisting of poly (3-hydroxybutyrate) (3HB), poly (4-hydroxybutyrate) (4HB), poly (3- hydroxyvalerate)(3HV), poly (3-hydroxybutyrate-co-3-hydroxyvalerate), poly (hydroxybutyrate-co-hydroxy hexanoate), poly (3 -hydroxy-co-4-hydroxybutyrate), their copolymers and mixtures thereof.
  4. 4. The packaging material according to claims 1, 2 or 3, wherein in said substrate, the polymeric component consists of a polyhydroxyalkanoate polymer or copolymer, of polybutylene succinate or of a blend of a polyhydroxyalkanoate and polybutylene succinate, wherein said blend contains: - from 50 to 70 % wt. of a polyhydroxyalkanoate and from 30 to 50 % wt. of polybutylene succinate with reference to 100 parts by weight of the polymeric component, and wherein said substrate further comprises up to 10 % wt. of a filler, referred to 100 parts by weight of the polymeric component, selected from the group consisting of a layered double hydroxide (LDH), clay, nanocellulose, starch and mixtures thereof.
  5. 5. The packaging material according to claim 4, wherein said substrate further comprises from 0.5 to 3 % wt. of cellulose nanocrystals (CNC), referred to 100 % wt. of the polymeric component.
  6. 6. The packaging material according to claim 4, wherein said substrate comprises from 0.5 to 10% wt of a dispersed layered double hydroxide (LDH) and from 7 to 9.5 % wt. of said fillers other than LDH, both referred to 100 parts by weight of the polymeric component.
  7. 7. The packaging material of any of claims 1 to 6, wherein the substrate is a composite coextruded film or sheet comprising a core layer and a skin layer thinner than the core layer on one or both sides of the core layer, wherein said core layer is a polymeric film of a polyhydroxyalkanoate or polybutylene succinate and mixtures thereof comprising a filler dispersed in the polymer matrix, selected from a layered double hydroxide, preferably in the amount of from 0.5 to 10 % wt. referred to the polymer matrix, and cellulose nanocrystals, preferably in the amount of from 0.5 to 3 % wt. , referred to the polymer matrix and said skin layer is a co-extruded coating consisting of a polymeric component selected from a polyhydroxyalkanoate, polybutylene succinate and mixtures thereof.
  8. 8. The packaging material according to any of claims 1 to 7, wherein said barrier coating is a heat- sealable layer of the packaging material and the polymeric component of said barrier coating consists of a polymer selected from the group consisting of a polyhydroxyalkanoate, polybutylene succinate, milk proteins, vegetable proteins, carrageenan or mixtures thereof having a heat-sealing temperature from 60 to 170°C.
  9. 9. The packaging material according to any of claims 1 to 8 wherein said barrier layer is a heat-sealable surface layer of the packaging material and the polymeric component of said barrier layer is a polyhydroxyalkanoate or a blend of polyhydroxyalkanoates having a heat-sealing temperature between 60 and 170C.
  10. 10. The packaging material of claim 1, wherein said barrier layer is obtained by applying and drying a lacquer comprising said polymeric component and filler in water or in a solvent vehicle.
  11. 11. The packaging material according to any of claims 1 to 7, further comprising a heat- sealable surface layer obtained from a lacquer comprising a heat sealable polymeric component and not including filler.
  12. 12. The packaging material according to any of claims 1 to 11, further comprising a surface protective coating on the side opposite the barrier layer with respect to the core, obtained from a varnish comprising a liquid vehicle selected from water, ethanol, ethyl acetate and polymer selected from nitrocellulose or chemically modified cellulose, polyacrylic polymers and polyurethane.
  13. 13. The packaging material according to any of the preceding claims further comprising a surface release coating comprising a slip or a release agent selected from the group consisting of silicone containing compounds, fatty acid or fatty acid esters, vegetable oils, carnauba wax and paraffin wax.
  14. 14. The packaging material according to any of the preceding claims further comprising a primer layer applied to one or both sides of the substrate in between the surface of the substrate layer and said barrier coating layer.
  15. 15. The packaging material according to any of the preceding claims, further comprising an ink printed layer.
  16. 16. The packaging material according to claim 1 comprising, as a surface layer, a cold sealable layer formulated from a latex suspension, optionally including additives or pigments.
  17. 17. A composite coextruded film or sheet comprising a core layer and a skin layer thinner than the core layer on one or both sides of the core layer, wherein said core layer is a polymeric film of a polyhydroxyalkanoate or polybutylene succinate and mixtures thereof comprising a filler dispersed in the polymer matrix, selected from a layered double hydroxide, preferably in the amount of from 0.5 to 10 % wt. referred to the polymer matrix, and cellulose nanocrystals, preferably in the amount of from 0.5 to 3 % wt. , referred to the polymer matrix and said skin layer is a co-extruded coating consisting of a polymeric component selected from a polyhydroxyalkanoate, polybutylene succinate and mixtures thereof.
  18. 18. The composite coextruded sheet of claim 17 which is thermoformable and has a thickness of from 500 to 1500 micron.

Description

Packaging Material The present invention relates to a multi-layer packaging material, particularly for use in packaging confectionary products, comprising a polymeric substrate and at least a barrier layer. Barrier coatings are required and widely used in food packaging to preserve the food organoleptic properties. Barrier properties for packaging materials, particularly for a confectionary product, include a low permeability to 02 and water vapor, as well as low permeability to volatile aroma compounds and low light permeability. Particularly, for packaging materials for use in the packaging of confectionary products it is desirable to achieve an oxygen transmission rate (OTR) lower than 100 or preferably lower than 0.1 cc/m224h, measured at 23 °C at 0% RH and a water vapor transmission rate (WVTR) lower than 10 or preferably lower than 0.1 g/m2 24 h at 38 °C at 90% RH. There is a need for packaging materials that are eco-sustainable, allowing the packagings to be compostable and easily recyclable in multiple environments. An object of the invention is to provide multilayer packaging with multiple materials that will still maintain the biodegradation and compostability properties while ensuring high level of protection that, as of today, biobased and biodegradable materials are lacking. This goal is reached by adding all natural additives/materials to make sure that in the biodegradation process no harming substances are going to be left behind in the soil or compost. Moreover, there is a need for packaging materials that combine the required barrier properties and the eco-sustainability properties, with mechanical properties that allow their use in modem high-speed packaging machines such as for instance flow-pack and flow-wrap machines and twist-wrap machines. Particularly desirable as mechanical properties are tensile strength and resistance to pierce. The purpose of the invention is to provide a multi-layer packaging material that combines the above-mentioned requirements. Summary of the invention In view of the above-mentioned purpose, the subject-matter of the invention is a multi-layer packaging material as defined in the appended claims. The dependent claims relate to preferred embodiments of the invention. Further characteristics and advantages of the packaging material of the invention will become clear from the detailed description that follows, made with reference to the attached drawings, provided by way of non-limiting example. Brief description of the drawings In the attached drawings: - Fig. 1 is a schematic sectional representation showing the layers layout of a plurality of embodiments (a) through (f) of the packaging material wherein a surface layer of the multi-layer structure has heat sealing properties; - Fig. 2 is a schematic sectional representation showing the layers layout of embodiments of the invention (a) though (c) wherein the multi-layer structure includes a surface layer having cold sealing properties, - Fig. 3 to 8 show preferred examples of composite coextruded substrates and - Fig. 9 and 10 show further exemplified embodiments. In the annexed drawings, the reference numerals indicate the following structural features: I polymeric substrate (single layer film or sheet or coextruded composite film or sheet); 3 core layer of a coextruded composite film or sheet; 5 skin layer(s) of a coextruded composite film or sheet; 7 barrier layer; 9 optional layer obtained by applying a heat sealable laquer; I I optional continuous or discontinuous cold sealable layer: 13 optional continuous or discontinuous printed layer; 15 optional layer obtained from a release varnish. Detailed description of the invention The invention relates to packaging materials having a multi-layer structure and comprising a substrate 1, which is a film or sheet of a (bio) degradable polymer or of a blend of (bio)degradable polymers. The (bio) degradable polymers are selected from the group consisting of a polyhydroxyalkanoate or a polyhydroxyalkanoate copolymer, polybutylene succinate or its copolymers, polylactic acid, polybutylene adipate terephthalate and mixtures thereof. The reference to a sheet includes thermoformed or thermoformable sheets. Polyhydroxyalkanoates (PHAs) for use as the substrate 1 preferably include medium chain length PHAs with 6-14 carbon atoms in their monomer units, that are soft and elastomeric with low melting points, typically from 50 to 170°, preferably from 100 to 160°; however, the term PHAs also includes short chain length and long chain length PHAs and/or mixtures thereof. Examples of poly (hydroxyalkanoate) polyesters that can be used within the scope of the invention include, but are not limited to, poly (3 -hydroxybutyrate) (3HB), poly (4- hydroxybutyrate) (4HB), poly (3- hydroxyvalerate)(3HV); particularly preferred are copolymers of hydroxybutyrate and hydroxyvalerate or hydroxyhexanoate which have a melting temperature of 120 to 160 0 C including, poly (3-hydroxybuty