Packaging materials with enhanced thermal-insulating performance
A thermo-insulating packaging material including a paper-based substrate layer, a paper-based top layer and a thermal-insulating composition positioned between the paper-based substrate layer and the paper-based top layer, the thermal-insulating composition including a filler, an organic binder and a plasticizer.
1. A thermo-insulating packaging material comprising:
(A) a paper-based substrate layer;
(B) a paper-based top layer; and
(C) a thermal-insulating composition positioned between the paper-based substrate layer and the paper-based top layer, the thermal-insulating composition comprising a filler, an organic binder and a plasticizer.
2. The material of claim 1 further comprising a moisture barrier layer, and wherein the moisture barrier layer is positioned on at least one of the paper-based substrate layer and the paper-based top layer.
3. The material of claim 1 wherein the filler comprises, based on total weight of the filler:
(i) inorganic filler in an amount of 0% to 90% by weight; and
(ii) organic filler in an amount of 10% to 100% by weight.
4. The material of claim 1 wherein the thermal-insulating composition is positioned on at least one of the paper-based substrate layer and the paper-based top layer in a form of coalesced droplets, longitudinally-extending sinuous strands, or combinations thereof.
5. The material of claim 1 wherein the thermal-insulating composition comprises a starch binder.
6. The material of claim 1 wherein the thermal-insulating composition further comprises borax.
7. The material of claim 1 wherein the thermal-insulating composition comprises ungelatinized starch and sodium silicate.
8. The material of claim 1 wherein the thermal-insulating composition comprises corn fibers as the filler in an amount of 0.5% to 1% by weight based on total weight of the composition.
9. The material of claim 1 wherein the filler comprises insulating particles selected from the group consisting of ceramic air-containing particles, pearlite particles, and combinations thereof.
10. The material of claim 1 wherein the organic binder comprises a member selected from the group consisting of styrene-butadiene polymer, an acrylic-styrene butadiene polymer, starch, polyvinyl alcohol, polyvinyl acetate, and combinations thereof.
11. The material of claim 1 characterized by a thickness of the thermal-insulating composition in a range of 0.05 mm to 5 mm.
12. The material of claim 1 wherein the thermal-insulating composition is applied to at least one of said paper-based substrate layer and said paper-based top layer as a fluid, and wherein the fluid has a pseudoplasticity index in a range of 0.3 to 0.5.
13. The material of claim 1 wherein the thermal-insulating composition is applied to at least one of said paper-based substrate layer and said paper-based top layer as a fluid, and wherein the fluid has a low shear viscosity in a range of 2,000 to 50,000 cps, and a high shear viscosity in a range of 100 to 5,000 cps.
14. The material of claim 1 characterized by a porosity of the paper-based substrate layer in a range 20 to 150 Gurley units.
15. The material of claim 1 characterized by a porosity of the paper-based top layer in a range 20 to 150 Gurley units.
16. The material of claim 1 wherein the filler comprises at least 15 percent by weight of the thermal-insulating composition.
17. The material of claim 16 wherein the organic binder comprises 15% to 70% by weight of the thermal-insulating composition.
18. The material of claim 1 wherein the thermal-insulating composition comprises cellulosic solids as the filler in an amount of 2% to 50% by weight based on total weight of the composition.
19. The material of claim 18 wherein the cellulosic solids have an average particle size of at least 100 microns.
20. The material of claim 18 wherein the cellulosic solids include a member selected from the group consisting of cellulosic fibers, wood flour, wood dust, gluten feed, and combinations thereof.