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US 4,360,486 AGranted
Process for introducing an additive material to polymeric foams
AssigneeMobil Oil Corporation
InventorsDaniel J. DiBiasi, Charles M. Krutchen
Life of this patent
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Abstract
Improved polymeric foams are obtained by the introduction of a beneficial additive to the system by dissolving said additive into a liquid foaming agent which is a solvent therefor, combining the solution with the polymer and extruding the polymer in foamed form.
Claims9
A process for preparing a foamed styrene polymer composition which comprises:
- introducing a polymer charge comprising virgin styrene polymer, free of any antioxidant, into a first comparatively high temperature stage of an extruder and melting the same;
- dissolving an antioxidant into a liquid foaming agent;
- introducing the antioxidant-foaming agent solution to the molten polymer under pressure and intimately mixing the combination;
- transporting the molten polymer to a comparatively low temperature stage of the extruder;
- and extruding the molten polymer in foamed form.
2 more elements
In the process for the preparation of polymer foam sheet comprising:
- melt blending a composition comprising virgin thermoplastic polymer, a nucleating agent and a volatile foaming agent,
- extruding said composition into a region of lower pressure to form a foamed sheet,
- thermoforming articles in said sheet,
- separating waste foam from said articles,
- reducing said waste to non-foam form, and
- recycling said non-foam waste in combination with said virgin polymer;
- the improvement which comprises,
- dissolving an additive material into the foaming agent while said foaming agent is in its liquid state, combining the thermoplastic polymer in its molten state with the additive-foaming agent solution in a comparatively high temperature stage of an extruder intimately mixing the combination, transporting said composition to a lower temperature stage of the extruder and extruding the composition in foamed sheet form.
5 more elements
Dependencies are inferred from the claim text.