Microcellular foam sheet and processes of making and using
AssigneeDart Container Corporation
InventorCHENGTAO LI
Life of this patent
Estimating the term…
Abstract
A solid state foaming process for generating a microcellular foam sheet for use in forming a container is provided includes a pre-foaming treatment phase prior to a solid state impregnation and foaming phase. The solid state microcellular foam sheet includes a central foamed section defining a foam layer within the microcellular foam sheet having a first population of cells within which are interspersed a second population of cells.
Claims27
A solid state foaming process for generating a microcellular foam sheet for use in forming a container, the process comprising:
- extruding a first layer including a first polymeric material and a blowing agent, wherein the first layer has a first density;
- a first expansion comprising at least partially expanding the first layer with the blowing agent to form a pre-foamed sheet comprising a pre-foamed layer having a second density, less than the first density;
- impregnating the pre-foamed layer in a solid state with a non-reacting gas that is soluble in the first polymeric material;
- and
- a second expansion comprising at least partially expanding the pre-foamed layer with the non-reacting gas to form a microcellular foam layer having a third density, less than the second density.
A solid state foamed microcellular foam sheet for use in forming a container, the microcellular foam sheet comprising:
- a central foamed section defining a foam layer within the microcellular foam sheet and having a first population of cells within which are interspersed a second population of cells having a smaller cell size than the first population of cells, wherein the second population of cells are formed in the material defining the first population of cells within the central foamed section;
- and
- one or more discrete foamed sections, one or more discrete unfoamed sections defining a skin layer, or a combination of one or more discrete foamed and unfoamed sections on one or both sides of the central foamed section.
The solid state foamed microcellular foam sheet according to any of the preceding claims comprising at least one of:
- a pair of unfoamed sections on both sides of the central foamed section;
- or
- at least one pair of discrete foamed sections between the central foamed section and each of the pair of unfoamed sections.
Dependencies are inferred from the claim text.