Abstract: A method for making low density (0.8-2 lb/cu.ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent, the process emitting blowing agent during processing in an amount of from only about 0.3 to about 2.5 weight percent. The process uses 2 to 5 expansion steps together with a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commercially viable processes for making expanded polystyrene products. The process can be used with or without a molding step.

Abstract: A polystyrene polymer as well as an expandable polystyrene formulation comprises a polystyrene polymer having a particular molecular weight distribution. The polymer itself exhibits a polydispersity of from about 1 to less tha 2.0, a weight average molecular weight of greater than about 200,000 to about 300,000, and an M.sub.z :M.sub.n of from about 2 to less than about 3.0. Furthermore, the polystyrene polymer is branched to from 0 to less than 5 weight percent.The expandable polystyrene formulation comprises a polystyrene polymer exhibiting a polydispersity of from about 1.0 to less than 2.5, a weight average molecular weight of from greater than about 180,000 to about 300,000, an M.sub.z :M.sub.n of from about 2 to about 4.5. The polystyrene polymer is present in an amount of from about 94.5 weight percent to about 98 weight percent, based on the total weight of the formulation, and the polystyrene polymer is branched to from 0 to less than 5 weight percent.

Abstract: A method for making low density (0.8-1.1 lb./cu.ft.) expanded polymeric products uses blowing agent in an amount of any from 2 to 4.4 weight percent and aging periods of from 1 to 80 hours after each expansion step. The process uses 2 to 5 expansion steps and a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing currently being used in commercially viable processes for making expanded polystyrene products. The process can be used with or without a molding step.

Abstract: A polystyrene polymer as well as an expandable polystyrene formulation comprises a polystyrene polymer having a particular molecular weight distribution. The polymer itself exhibits a polydispersity of from about 1 to less than 2.0, a weight average molecular weight of greater than about 200,000 to about 300,000, and an M.sub.z :M.sub.n of from about 2 to less than about 3.0. Furthermore, the polystyrene polymer is branched to from 0 to less than 5 weight percent.The expandable polystyrene formulation comprises a polystyrene polymer exhibiting a polydispersity of from about 1.0 to less than 2.5, a weight average molecular weight of from greater than about 180,000 to about 300,000, an M.sub.z :M.sub.n of from about 2 to about 4.5. The polystyrene polymer is present in an amount of from about 94.5 weight percent to about 98 weight percent, based on the total weight of the formulation, and the polystyrene polymer is branched to from 0 to less than 5 weight percent.

Abstract: A method for making low density (0.8-1.1 lb/cu.ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent and aging periods of from 1 to 80 hours after each expansion step. The process uses 2 to 5 expansion steps and a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commerically viable processes for making expanded polystyrene products. The process can be used with or without a molding step.

Abstract: A method for making low density (0.8-1.1 lb/cu.ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent. The process uses 2 to 5 expansion steps together with a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commercially viable processes for making expanded polystyrene products. The process can be used with or without a molding step.

Abstract: A method for making low density (0.8-1.1 lb/cu. ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent. The process uses 2 to 5 expansion steps together with a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commercially viable processes for making expanded polystyrene products. The process can be used with or without a molding step.

Abstract: A method for making low density (0.8-2 lb/cu.ft.) expanded polymeric products uses blowing agent in an amount of only from 2 to 4.4 weight percent, the process emitting blowing agent during processing in an amount of from only about 0.3 to about 2.5 weight percent. The process uses 2 to 5 expansion steps together with a polymer having a particular polydispersity, weight average molecular weight and M.sub.z :M.sub.n, this polymer having a greater expandability than conventional polymers. The process requires only about half of the amount of blowing agent currently being used in commerically viable processes for making expanded polystyrene products. The process can be used with or without a molding step.