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US 10,584,225 B2Granted
Production of fine-pored PMMA foams using nucleating agents
AssigneeEvonik Roehm GmbH
InventorsThomas Richter, Christoph Seipel, Kay Bernhard, Sivakumara K Krishnamoorthy, Sebastian Buehler
Life of this patent
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Abstract
Fine-cell PMMA foams are produced using a production process including nucleators in addition to suitable blowing agents. It was found that, surprisingly, a simple-to-produce stable PMMA foam having very fine cells and very good properties can be produced.
Claims9
A process for producing a polymethacrylate foam,
- polymerizing a composition comprising:
- from 0.01 to 2.0 wt % of an initiator,
- from 2 to 20 wt % of a blowing agent selected from the group consisting of urea, tert-butyl (meth)acrylate, isopropyl (meth)acrylate, tert-butyl methyl ether, and poly(tert-butyl (meth)acrylate),
- from 0.2 to 10 wt % of silicon oxide particles having a diameter between 4 and 1000 nm as nucleating agent and from 70 to 97.79 wt % of a polymer-forming mixture,
- wherein said polymer-forming mixture comprises:
- methyl methacrylate (MMA) and/or MMA repeat units to an extent of not less than 75 mol % and may be present as polymer and/or oligomer to an extent of from 0 to 80 wt %, wherein said polymerizing proceeds at a temperature between 20° C. and 100° C., to obtain a polymerized composition, and
- subsequently foaming said polymerized composition at a temperature between 130° C. and 250° C. to obtain a rigid polymethacrylate foam.
4 more elements
Dependencies are inferred from the claim text.