Closed cell foam and associated expandable composition, foam-forming process, and article
AssigneeShpp Global Technologies B.V.
InventorsErin DIKEMAN, Thomas P. GRECO, Scott SIMPSON, Jon M. GIRARD
Life of this patent
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Abstract
A polyetherimide-based foam contains specific amounts of a nucleating agent and a polyetherimide having a weight average molecular weight of 30,000 to 80,000 grams per mole and a dispersity of 2.7 to 4.5. The foam has a density of 20 to 60 kilograms per meter3, and a closed cell content of 80 to 100 percent. The foam can be prepared by a method that combines the nucleating agent and polyetherimide with a blowing agent that includes specific amounts of acetone and methanol. Also described are articles that include the foam.
Claims13
A polyetherimide-based foam, comprising:
- 96 to 99.8 parts by weight of a polyetherimide having a weight average molecular weight of 30,000 to 80,000 grams per mole and a dispersity of 2.7 to 4.5 determined by gel permeation chromatography using polystyrene standards;
- and
- 0.2 to 4 parts by weight of a nucleating agent;
- wherein parts by weight are based on 100 parts by weight total of the polyetherimide and the nucleating agent;
- wherein the polyetherimide-based foam has a density of 20 to 60 kilograms per meter3 determined at 23° C. according to ASTM D1622-14;
- and
- wherein the polyetherimide-based foam has a closed cell content of 80 to 100 percent, determined according to ASTM D6226-15.
An expandable polyetherimide composition, comprising:
- 96 to 99.8 parts by weight of a polyetherimide having a weight average molecular weight of 30,000 to 80,000 grams per mole and a dispersity of 2.7 to 4.5, determined by gel permeation chromatography using polystyrene standards;
- 0.2 to 4 parts by weight of a nucleating agent;
- and
- 4.1 to 7 parts by weight of a blowing agent comprising
- 4 to 6 parts by weight acetone and
- 0.1 to 1 part by weight methanol;
- wherein all parts by weight are based on 100 parts by weight total of the polyetherimide and the nucleating agent.
A method of forming a polyetherimide-based foam, comprising:
- forming an expandable composition by melt blending
- 96 to 99.8 parts by weight of a polyetherimide having a weight average molecular weight of 30,000 to 80,000 grams per mole and a dispersity of 2.7 to 4.5, determined by gel permeation chromatography using polystyrene standards,
- 0.2 to 4 parts by weight of a nucleating agent, and
- 4.1 to 7 parts by weight of a blowing agent comprising
- 4 to 6 parts by weight acetone and
- 0.1 to 1 part by weight methanol,
- wherein all parts by weight are based on 100 parts by weight total of the polyetherimide and the nucleating agent;
- and
- extruding the expandable composition through a die to form a polyetherimide-based foam having a density of 20 to 60 kilograms per meter3 determined at 23° C. according to ASTM D1622-14, and a closed cell content of 80 to 100 percent, determined according to ASTM D6226-15;
- wherein the extruding comprises maintaining a die melt temperature of 195 to 230° C., and a mass flux ratio of 0.035 to 0.065, wherein mass flux ratio is defined as a ratio of mass flux after the die to mass flux before the die.
Dependencies are inferred from the claim text.