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US 5,688,832 AGranted
Low molecular weight alkenyl aromatic polymer foam
AssigneeThe Dow Chemical Company
InventorsAndrew N. Paquet, Warren H. Griffin
Life of this patent
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Abstract
Disclosed is a foam structure of desirable mechanical strength made with a low molecular weight alkenyl aromatic polymer material and an inorganic blowing agent. The polymer material has an alkenyl aromatic polymer of a weight average molecular weight of 100,000 to 165,000. The foam structure can be made in processes with reduced pressure drop.
Claims12
A process for making an extruded alkenyl aromatic polymer foam structure having a cross-section thickness in minor dimension of greater than 9.5 millimeters and a cross-section of 30 square centimeters or more, comprising:
- a) heating to form a melt polymer material an alkenyl aromatic polymer material comprising greater than 50 percent by weight alkenyl aromatic monomeric units and further comprising a weight average molecular weight of 125,000 to to 145,000 and a polydispersity index of 2.05 to 3.0;
- b) incorporating into the melt polymer material at an elevated pressure a blowing agent comprising 50 percent or more by weight of an inorganic blowing agent based upon the total weight of the blowing agent to form a foamable gel;
- c) cooling the foamable gel to an optimum foaming temperature;
- and
- d) extruding the foamable gel through a die to a zone of lower pressure to form a foam structure.
2 more elements
Dependencies are inferred from the claim text.