Publication NumberUS 10214316
Assignees
  • STORA ENSO OYJ
StatusIssued Patent
Application Number14/438180
AvailabilityUnknown
Filing Date2013-10-23
Publication Date2019-02-26

Abstract

A biodegradable packaging material, a method of manufacturing the same, as well as products made of the material wherein a multilayer coating coextruded onto a fibrous substrate the multilayer coating comprising innermost and outermost layers of a blend comprising 20-95 wt-% of a higher melt index polylactide and 5-80 wt-% of another biodegradable polymer such as polybutylene succinate, and a middle layer containing a lower melt index polylactide alone. The goal is to increase machine speed in coextrusion while maintaining good adhesiveness to the substrate and good heat-sealability of the coating. The products include disposable drinking cups and board trays, as well as sealed carton packages for solids and liquids.

Claims

  • 1. A biodegradable packaging material, comprising: a multilayer coating coextruded on a fibrous substrate, said coextruded multilayer coating comprising (i) an innermost layer of a blend comprising 20-95 wt-% of a first polylactide and 5-80 wt-% of another biodegradable polymer, (ii) a middle layer consisting of 100 wt-% of a second polylactide, and (iii) an outermost layer of a blend comprising 20-95 wt-% of a third polylactide and 5-80 wt-% of another biodegradable polymer, wherein the first polylactide having a higher melt index of more than 35 g/10 min (210° C.; 2.16 kg), the second polylactide having a lower melt index of 5-35 g/ 10 min (210° C.; 2.16 kg), and the third polylactide having a higher melt index of more than 35 g/10 min (210° C.; 2.16 kg).
  • 2. The biodegradable packaging material of claim 1, wherein the same blend has been used for the innermost and the outermost layers of the multilayer coating.
  • 3. The biodegradable packaging material of claim 2, wherein the blends of the innermost and outermost layers comprise 30-60 wt-% of polylactide having a higher melt index of 50-100 g/10 min (210° C.; 2.16 kg), 40-70 wt-% of said another biodegradable polymer, and 0-5 wt-% of an acrylic copolymer.
  • 4. The biodegradable packaging material of claim 1 in the form of a drinking cup having an inner liquid-contact side, the multilayer located on the inner liquid-contact side of the cup.
  • 5. The biodegradable packaging material of claim 1 in the form of a scaled liquid package having an inner liquid-contact side, the multilayer coating located on the inner liquid-contact side of the sealed liquid package.
  • 6. The biodegradable packaging material of claim 1 in the form of a sealed carton package having an outside, the multilayer coating located on the outside of the sealed carton package.
  • 7. The biodegradable packing material of claim 1 in the form of a tray package for ready-made food having at least one food contact side, the multilayer coating located on said at least one food contact side of the tray package.
  • 8. The packaging material of claim 1, wherein the first and third polylactides are the same having the same higher melt index.