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EP-4739483-A1 - A MATERIAL USEFUL FOR A PACKAGE AND A METHOD FOR MAKING SUCH MATERIAL

EP4739483A1EP 4739483 A1EP4739483 A1EP 4739483A1EP-4739483-A1

Abstract

The present invention relates to a method for making granule suitable for use in a package or similar, and use of said granule e.g. in package applications.

Inventors

  • SVEDBERG, ANNA
  • WALLSTÉN, Sara
  • NORDIN, JAN

Assignees

  • CELLOFIBERS SWEDEN AB

Dates

Publication Date
20260513
Application Date
20240620

Claims (10)

  1. 1 . A method for manufacturing lightweight granules, which may be used for flexible, molded foamed packaging materials, from >95% lignocellulose base, comprising the following steps: a) providing lignocellulosic material, preferably cellulosic fibers, in a pumpable aqueous suspension and b) optionally, adding a debonding agent, and/or a plasticizer, and optionally, which is preferred, applying a high shear defibrillation step to increase the surface area in the system, and c) providing one or more expandable particles and/or pre-expanded particles and optionally light weight particles, and mixing said lignocellulosic material with said particles, d) adding a binding agent and/or a polymeric flocculation agent, and e) dewatering the mix, thus providing a homogeneous matrix, preferably to a solid content of from about 20 to about 40%, most preferred using centrifugation and/or a press filter, and f) granulating thus providing granules, preferably whereby charging the wet fiber-based material mix into a high shear granulator to make granules or conveying said material onto a fluid bed to make granules, optionally followed by drying said granules.
  2. 2. A method according to claim 1 wherein the lignocellulosic material emanates from chemical thermomechanical pulp, thermomechanical pulp, sulfate pulp, such as Kraft pulp, sulfite pulp, recycled pulp material, rejected pulp material, board or carton, or a combination thereof.
  3. 3. A method according to claim 1 wherein the lignocellulosic material emanates from bleached or non-bleached pulp, or a combination thereof.
  4. 4. A method according to claim 1 wherein the lignocellulosic material emanates from hardwood or softwood, bagasse, algae or straw or a combination thereof.
  5. 5. A method according to claim 1 wherein said drying of step f) is performed to achieve from about 70 to about 100% dryness through using one or more of the following processes: through fluid bed drying using hot air, or using InfraRed radiation, or using hot air without using fluid bed, preferably wherein the drying temperature is below about 100 °C.
  6. 6. A granule obtainable by a method according to any one of claims 1 - 5.
  7. 7. Use of a granule according to claim 6 in flexible, molded foamed packaging materials, a container or a package, wherein said container may be a disposable drinking cup or dairy product carton or auto-clave package or a tray, or a plate for eating or keeping food, or a box for keeping fruit or fish or shell fish, or in the manufacturing of a chock absorbing material, or an insulation material for building constructions or an isolation material for keeping warm or cold food or food ingredients, or in an environmentally friendly shock absorbing packaging material, preferably recyclable with paper board.
  8. 8. A method for manufacturing of a foamed product, preferably comprising less than about 5 % of a fossil-based polymer or plastic material, comprising the following steps: i) providing one or more granules obtained by a process according to any one of claims 1 - 5, or one or more granules according to claim 6, ii) filling said granules into a mold assembly and heating said material from about 50 to about 150° C, preferably from about 50 to about 120° C, most preferred from about 60 to about 100° C, thus providing a dry content of from about 60 to about 90% and thus providing an expanded foamed product, especially preferred wherein steam is applied during step ii) for expanding said granules.
  9. 9. A method according to claim 8 wherein the density of said finalized foamed product is from about 0.025 to about 0.5 g/cm 3 , preferably from about 0.05 to about 0.5 g/cm 3 .
  10. 10. A foamed molded product obtainable by a method according to any one of the claims 8 - 9.

Description

A material useful for a package and a method for making such material Field of the invention The present invention relates to a method for making a granule, suitable for making a package or similar, and usage thereof and its end product. Background The application and manufacture of expanded PS (expanded polystyrene, EPS) or PP (expanded polypropylene, EPP) for use in packages and in various construction applications have previously been described. However, these foamed and/or molded products are still based upon raw material emanating from fossil resources, e.g. oil. The production of EPS yearly embraces millions of tonnes worldwide, and only a fraction of said products are recycled and some even estimate that some landfills may comprise from 25 - 35 wt % of EPS. Through EP0752444-A1 there is described a moldable pulp material useful for the production of environmentally friendly shock absorbing packaging for electric appliances as a substitute for polystyrene foam packaging. In the method, 1 to 5 weight % thermally expandable hollow particles are mixed with a pulp, comprised of strips of paper, and a starch binder in water. The mixture is filled into a mold assembly and compressed under heat to produce a molded pulp product. Through WO0154988-A2 there is described a low-density paperboard article useful as insulated container instead of using EPS. The method includes providing a papermaking furnish containing cellulosic fibers, and from about 0.25 to about 10 % by weight dry basis expandable microspheres, preferably from about 5 to about 7 wt. %, forming a paperboard web from the papermaking furnish on a papermaking machine. The density is mentioned to be 6.0 to about 10 lb/3MSF/mil. Through US2018072860A1 there is disclosed thermoplastic expandable microspheres glued onto cellulose fibers. These are not granules, not at all free-flowing light-weight granules of cellulose fibers and expandable microspheres. Thus, these will not fill a mold. Through DE3444264A1 it is described dewatering of a slurry of lignocellulosic material and expandable microspheres by filtering or pressing and expanding the microspheres by providing heat. However, said method does not provide for a method that may make flexible foamed and molded products at virtually any shape. There is thus a need for material useful in packages that are minimizing the usage of fossil resources for their raw material, at the same time also providing an easy to handle material, and at the same time providing a reasonable density such as a density from about 0.05 to about 0.8 g/cm3. There is a strong benefit also if the new material can be recycled in the established recycle streams (curb side) for paper and board. In addition, said new material may also be used drop-in in existing equipment for producing EPS. Summary of the invention The present invention solves/alleviates one or more of the above problems by providing according to a first aspect a method for manufacturing lightweight granules, which may be used for flexible, molded foamed packaging materials, from >95% lignocellulose base, comprising the following steps: a) providing lignocellulosic material, preferably cellulosic fibers, in a pumpable aqueous suspension and b) optionally, adding a debonding agent, and/or a plasticizer, and optionally; which is preferred, applying a high shear defibrillation step (grinding) to increase the surface area in the system, and c) providing one or more expandable particles and/or pre-expanded particles and optionally light weight particles, and mixing said lignocellulosic material with said particles, and d) adding a binding agent and/or a polymeric flocculation agent, and e) dewatering the mix, thus providing a homogeneous matrix, preferably to a solid content of from about 20 to about 40%, most preferred using centrifugation and/or a press filter, and f) granulating, thus providing granules, preferably whereby charging the wet fiber-based material mix into a high shear granulator to make granules or conveying said material onto a fluid bed to make granules, optionally followed by drying said granules. According to a second aspect of the present invention there is provided a granule obtainable by a method according to the first aspect. According to a third aspect of the present invention there is provided use of the granule according to the second aspect in flexible, in molded foamed packaging materials, a container or a package, wherein said container may be a disposable drinking cup or dairy product carton or auto-clave package or a tray, or a plate for eating or keeping food, or a box for keeping fruit or fish or shell fish, or in the manufacturing of a chock absorbing material, or an insulation material for building constructions or an isolation material for keeping warm or cold food or food ingredients, or in an environmentally friendly shock absorbing packaging material which may be recyclable with paper board. Also provided according to a fourt