Abstract: The invention relates to foam beads of propylene polymers which comprise more than 40% of open cells. They are produced by impregnating propylene polymer minigranules which comprise from 1 to 40% by weight of a cell opener with a volatile blowing agent in aqueous suspension and subsequently decompressing the mixture.

Abstract: The invention relates to expandable polyolefin beads which comprise blowing agent and have been coated with from 0.01 to 3% by weight of a salt and/or ester of a long-chain fatty acid, preferably with calcium stearate, to prevent caking during foaming.

Abstract: A process prepares expandable propylene polymer beads by mixing propylene polymer melt with a volatile organic blowing agent and with a nucleating agent in an extruder, whereupon the extrusion and pelletization of the extruded takes place in a water bath under conditions of temperature and pressure at which practically no foaming of the pellets takes place.

Abstract: The invention relates to expandable polyolefin particles containing expanding agents, said particles being coated with between 0.01 and 3 wt. % of a salt and/or an ester of a long-chained fatty acid, preferably with calcium stearate, in order to prevent agglutination during expansion.

Abstract: A process prepares expandable propylene polymer beads by mixing propylene polymer melt with a volatile organic blowing agent and with a nucleating agent in an extruder, whereupon the extrusion and pelletization of the extrudate takes place in a water bath under conditions of temperature and pressure at which practically no foaming of the pellets takes place.

Abstract: The invention relates to expandable olefin bead polymers which comprise a blowing agent with a boiling point of from −5 to 150° C., selected from the group consisting of alkanes, alkanols, ketones, ethers and esters. The particles are unfoamed and have a bulk density above 500 g/l, and can be foamed to a bulk density below 200 g/l after storage for one hour at room temperature in free contact with the atmosphere. They are prepared by impregnating polyolefin pellets in suspension in a pressure vessel with the blowing agent, cooling the batch below 100° C., reducing the pressure and isolating the particles.

Abstract: The invention relates to expandable olefin bead polymers which comprise a blowing agent with a boiling point of from −5 to 150° C., selected from the group consisting of alkanes, alkanols, ketones, ethers and esters. The particles are unfoamed and have a bulk density above 500 g/l, and can be foamed to a bulk density below 200 g/l after storage for one hour at room temperature in free contact with the atmosphere. They are prepared by impregnating polyolefin pellets in suspension in a pressure vessel with the blowing agent, cooling the batch below 100° C., reducing the pressure and isolating the particles.

Abstract: A process prepares expandable propylene polymer beads by mixing propylene polymer melt with a volatile organic blowing agent and with a nucleating agent in an extruder, whereupon the extrusion and pelletization of the extrudate takes place in a water bath under conditions of temperature and pressure at which practically no foaming of the pellets takes place.

Abstract: The invention relates to expandable olefin bead polymers which comprise a blowing agent with a boiling point of from −5 to 150° C., selected from the group consisting of alkanes, alkanols, ketones, ethers and esters. The particles are unfoamed and have a bulk density above 500 g/l, and can be foamed to a bulk density below 200 g/l after storage for one hour at room temperature in free contact with the atmosphere. They are prepared by impregnating polyolefin pellets in suspension in a pressure vessel with the blowing agent, cooling the batch below 100° C., reducing the pressure and isolating the particles.