초록 ▼

Disclosed is an extruded, unitary, closed-cell olefin polymer foam structure in plank form. The foam structure has a cross-section of 2 or more inches in one dimension and 18 or more inches in the other dimension. The olefin polymer material has a melt index of about 3.5 grams/10 minutes or less. Th

Disclosed is an extruded, unitary, closed-cell olefin polymer foam structure in plank form. The foam structure has a cross-section of 2 or more inches in one dimension and 18 or more inches in the other dimension. The olefin polymer material has a melt index of about 3.5 grams/10 minutes or less. The foam structure contains a blowing agent of about 75 mole percent or more 1,1-difluoroethane based upon the total moles of blowing agent. Further disclosed is a process for making the foam structure at a shear rate of about 400/second or more. It was found surprising that 1,1-difluoroethane which has relatively low solubility in olefin polymers, could be used to make olefin polymer foam structures of large cross-section.

대표청구항 ▼

The process for making an extruded, closed-cell olefin polymer foam structure in plank form having a cross-section in one dimension of 2 or more inches and 18 or more inches in the other dimension and a density of 48 kilograms per cubic meter or less, comprising: a) heating an olefin polymer materia

The process for making an extruded, closed-cell olefin polymer foam structure in plank form having a cross-section in one dimension of 2 or more inches and 18 or more inches in the other dimension and a density of 48 kilograms per cubic meter or less, comprising: a) heating an olefin polymer material comprising greater than 50 percent by weight olefin monomeric units to form a melt polymer material, the olefin polymer material having a melt index of about 3.5 grams/10 minutes or less; b) incorporating into the melt polymer material at an elevated pressure a blowing agent to form a foamable gel wherein the blowing agent consists essentially of 1,1-difluoroethane; c) cooling the foamable gel to an optimum foaming temperature; and d) extruding the foamable gel through a die at a shear rate of about 400/second or more into a region of reduced pressure to form the foam structure.