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US 10,675,792 B2Granted
Method for producing three dimensional foam articles
OwnerPaul Jacobsinventor
Life of this patent
Estimating the term…
Abstract
A process for making a three dimensional foam article of non-uniform shape employs a two-stage nitrogen autoclave process and a pre-form which has a non-uniform cross-section in at least one dimension.
Claims29
A process for making a three dimensional foam article of non-uniform shape comprising the steps of:
- (a) providing a pre-form comprising a polymer in a pressure vessel;
- (b) subjecting the pre-form to at least one inert gas at a first pressure higher than atmospheric pressure in order to drive the at least one inert gas into the pre-form;
- (c) raising the temperature of the pre-form to a temperature at or above its softening point, wherein steps (b) and (c) can take place in any order or simultaneously;
- (d) reducing the first pressure to a second pressure higher than atmospheric pressure but lower than the first pressure of step (b) and then cooling the pre-form to below its softening point to result in a partially expanded article;
- (e) transferring said article to a second vessel and heating it to a temperature above its softening point under a pressure of inert gas or air;
- and
- (f) reducing the pressure whilst maintaining temperature of said article at or above the softening point of the polymer, in order to expand the partially expanded article to form a foamed article;
- wherein the cross-section of the pre-form in at least one dimension is non-uniform;
- and
- wherein the pre-form is comprised of areas of different materials.
7 more elements
A process for making a three dimensional foam article of non-uniform shape comprising the steps of:
- (a) cross-linking by irradiation a polymer pre-form by exposing different areas of the pre-form to different levels of irradiation, and disposing the resulting cross-linked pre-form in a pressure vessel;
- (b) subjecting the pre-form to at least one inert gas at a first pressure higher than atmospheric pressure in order to drive the at least one inert gas into the pre-form;
- (c) raising the temperature of the pre-form to a temperature at or above its softening point, wherein steps (b) and (c) can take place in any order or simultaneously;
- (d) reducing the first pressure to a second pressure higher than atmospheric pressure but lower than the first pressure of step (b) and then cooling the pre-form to below its softening point to result in a partially expanded article;
- (e) transferring said article to a second vessel and heating it to a temperature above its softening point under a pressure of inert gas or air;
- and
- (f) reducing the pressure whilst maintaining temperature of said article at or above the softening point of the polymer, in order to expand the partially expanded article to form a foamed article;
- wherein the cross-section of the pre-form in at least one dimension is non-uniform.
5 more elements
Dependencies are inferred from the claim text.