Abstract: 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.

Abstract: Disclosed is a cross-linked ethylenic polymer foam structure of an ethylenic polymer material of a cross-linked, substantially linear ethylenic polymer. The substantially linear ethylenic polymer having in an uncross-linked state has: a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation: M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylenic polymer having about the same I.sub.2 and M.sub.w /M.sub.n. Further disclosed is a process for making the above foam structure.

Abstract: Disclosed is an ethylene polymer foam structure having enhanced processing and physical properties. The foam structure comprises an ethylenic polymer material and a blowing agent of isobutane and 1,1-difluoroethane. Further disclosed is a process for making the foam structure.

Abstract: Disclosed is an ethylene polymer foam structure having enhanced processing and physical properties. The foam structure comprises an ethylenic polymer material and a blowing agent. The blowing agent has a primary blowing agent of isobutane and a secondary blowing agent of 1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane, or a blend of them. Further disclosed is a process for making the foam structure.

Abstract: Disclosed is a cross-linked ethylenic polymer foam structure of an ethylenic polymer material of a cross-linked, substantially linear ethylenic polymer. The substantially linear ethylenic polymer having in an uncross-linked state has: a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation: M.sub.w /M.sub.n <(I.sub.10 /I.sub.2)-4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylenic polymer having about the same I.sub.2 and M.sub.w /M.sub.n. Further disclosed is a process for making the above foam structure.

Abstract: Disclosed is an ethylenic polymer foam structure comprising an ethylenic polymer material. The ethylenic polymer material contains a substantially linear ethylenic polymer having: a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation M.sub.w /M.sub.n .gtoreq.(I.sub.10 /I.sub.2)-4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear olefin polymer having about the same I.sub.2 and M.sub.w /M.sub.n. The foam structures have toughness and elasticity similar to those formed from conventional LLDPE without the poor dimensional stability and foam quality associated with those structures. The foam structures have foam quality similar to those made with conventional LDPE but with enhanced toughness and elasticity. Further disclosed is a process for making the above foam structure and making it in a foam bead form.

Abstract: Disclosed is a process for making a low density, dimensionally-stable, open-cell, extruded propylene polymer foam comprising primarily an expanded propylene polymer material wherein the foam has a blowing agent comprising greater than 85 percent by weight of one or more organic blowing agents based upon the total weight of the blowing agent. The propylene polymer material comprises more than 50 weight percent or more of propylene monomeric units based upon the total weight of the propylene polymer material. The foam has a density about 96 kilograms or less per cubic meter. The foam is greater than 20 percent open cell.

Abstract: Disclosed is an ethylenic polymer foam structure comprising an ethylenic polymer material. The ethylenic polymer material contains a substantially linear ethylenic polymer having: a) a melt flow ratio, I.sub.10 I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear olefin polymer having about the same I.sub.2 and M.sub.w /M.sub.n. The foam structures have toughness and elasticity similar to those formed from conventional LLDPE without the poor dimensional stability and foam quality associated with those structures. The foam structures have foam quality similar to those made with conventional LDPE but with enhanced toughness and elasticity. Further disclosed is a process for making the above foam structure and making it in a foam bead form.

Abstract: Disclosed is a process for making closed-cell, alkenyl aromatic polymer foam packing bodies. An alkenyl aromatic polymer material is heated to form a melt polymer material. The melt polymer material comprises greater than 50 percent by weight alkenyl aromatic monomeric units. A blowing agent is incorporated into the melt polymer material at an elevated pressure to form a foamable gel. The blowing agent has about 20 weight percent or more based upon the total weight of the first blowing agent selected from the group consisting of carbon dioxide and ethane. The foamable gel is extruded through a die to form a foam strand. The foam strand is pelletized to form a plurality of foam bodies. The bodies are further expanded by exposing them one or more times to heated air or steam. Preferably, the bodies are allowed to age for a preselected period of time after pelletizing and between subsequent expansions.

Abstract: Disclosed is a cross-linked ethylenic polymer foam structure of an ethylenic polymer material of a cross-linked, substantially linear ethylenic polymer. The substantially linear ethylenic polymer having in an uncross-linked state has: a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63; b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation: M.sub.w /M.sub.n .gtoreq.(I.sub.10 /I.sub.2)- 4.63; and c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylenic polymer having about the same I.sub.2 and M.sub.w /M.sub.n. Further disclosed is a process for making the above foam structure.

Abstract: Olefin polymer foams prepared utilizing "soft" blowing agents have improved properties when a small amount of a stability control agent comprising a glycerol monoester of a C.sub.20-24 fatty acid is employed.

Abstract: The use in otherwise conventional polyolefin extrusion foaming process of a stability control agent, in conjunction with certain binary or tertnary mixed blowing agent systems containing 1,2-dichlorotetrafluoroethane provides closed-cell olefin polymer foam articles having increased maximum cross-sections, smooth skins and good dimensional stability.

Abstract: An expandable ethylenic or styrenic polymer composition for production of lightly crosslinked foamed polymers and a process for controlling the degree of crosslinking of the polymer prior to extrusion foaming. The control is obtained by use of (a) a reversible gas-yielding crosslinking reaction which is delayed in the foam extrusion line in the presence of gaseous products (alcohols) and (b) added amounts of an alcohol such as an aliphatic alcohol. Suitable crosslinking agents include silanes, azido functional silanes, titanates, and amino compounds.

Abstract: An expandable alkenyl aromatic polymer composition and methods of preparation are provided. The composition is admixed with a volatile blowing agent and an expansion aid which includes a polyphenylene ether. The composition may be extruded and then expanded by exposure to steam or hot air or may be impregnated with blowing agent and then expanded.

Abstract: Novel foamed thermoplastic resins are disclosed. The foam includes an ionically associated blend containing at least about 60 weight % of a metal salt of a styrene-acrylic acid copolymer and at least 1 weight % of a metal salt of an ethylene-acrylic acid copolymer. The foams typically are prepared by extruding a ternary mixture of a styrene-acrylic acid copolymer, an ethylene-acrylic copolymer and an alkali metal bicarbonate which functions as the foaming agent. The ionically associated blends included in the foam are believed to be novel compositions of matter.

Abstract: A substantially closed-celled linear polyolefin foam is made by melt processing under pressure a linear polyolefin together with a volatile blowing agent and a crosslinking agent and then expanding the polymer. Suitable crosslinking agents, including azido and vinyl functional silanes, organic peroxides, multifunctional vinyl monomers, and oxygen, increase the melt tension and melt viscosity of the polymer by lightly crosslinking the polymer with itself to enable the production of foams having improved properties in comparison with branched polyolefin foams.

Abstract: An expandable alkenyl aromatic polymer composition and methods of preparation are provided. The composition is admixed with a volatile blowing agent and an expansion aid which includes a polyphenylene ether. The composition may be extruded and then expanded by exposure to steam or hot air or may be impregnated with blowing agent and then expanded.

Abstract: An expandable ethylenic or styrenic polymer composition for production of lightly crosslinked foamed polymers and a process for controlling the degree of crosslinking of the polymer prior to extrusion foaming. The control is obtained by use of (a) a reversible gas-yielding crosslinking reaction which is delayed in the foam extrusion line in the presence of gaseous products (alcohols) and (b) added amounts of an alcohol such as an aliphatic alcohol. Suitable crosslinking agents include silanes, azido functional silanes, titanates, and amino compounds.

Abstract: A process for dimensionally stabilizing low density foamed polyolefins utilizing a dimensionally stabilizing control additive comprising a nitrogen-containing compound (having an unsaturated leg) said compound represented by formulas (I) and (II): ##STR1##

Abstract: An expandable polyolefin composition and a method of preparation are provided. Isobutane or mixtures of isobutane with other physical blowing agents are utilized to expand polyolefin compositions which have been modified by the addition of a stability control agent. The composition has a high degree of dimensional stability and exhibits minimal shrinkage during curing and/or aging.