摘要:
Polymer extruded foams that contain cell size enlarging agents are provided. The inventive composition includes a foamable polymer material, at least one blowing agent, and at least one cell size enlarging agent. The blowing agent utilized in the inventive composition is preferably selected such that the composition has a zero ozone depletion and low global warming potential. Examples include any inorganic blowing agents and/or non-hydrogenated chlorofluorocarbons (non-HCFCs). The foamable polymer material is preferably polystyrene. The cell size enlarging agent may be chosen from ethylene vinyl acetate (EVA) and/or ethylene methyl acrylate (EMA). The cell size enlarging agent permits the formation of a foam with large cell sizes that are desirable to achieve a high insulation value and to optimize the physical properties of the foamed product. In addition, the cell size enlarging agent provides an increased cell size to the foamed product without detracting from the physical and thermal properties.
摘要:
Polymer extruded foams that contain cell size enlarging agents are provided. The inventive composition includes a foamable polymer material, at least one blowing agent, and at least one cell size enlarging agent. The blowing agent utilized in the inventive composition is preferably selected such that the composition has a zero ozone depletion and low global warming potential. Examples include any inorganic blowing agents and/or non-hydrogenated chlorofluorocarbons (non-HCFCs). The foamable polymer material is preferably polystyrene. The cell size enlarging agent may be chosen from ethylene vinyl acetate (EVA) and/or ethylene methyl acrylate (EMA). The cell size enlarging agent permits the formation of a foam with large cell sizes that are desirable to achieve a high insulation value and to optimize the physical properties of the foamed product. In addition, the cell size enlarging agent provides an increased cell size to the foamed product without detracting from the physical and thermal properties.
摘要:
Polymeric foam and polymeric foam products that contain a foamable polymer material, nanographite, and 1,1,2,2-tetrafluoroethane (HFC-134) are provided. Preferably, the foamable polymer material is an alkenyl aromatic polymer material. The foam is free of other conventional blowing agents typically utilized in preparing a foamed product. The nanographite is not chemically or surface modified and is preferably compounded in a polyethylene methyl acrylate copolymer (EMA), which is used both as a medium and a carrier for the nanographite. The nanographite may be compounded in the polymer in an amount up to 60% loading. In addition, the nanographite acts as a nucleating agent, R-value enhancer, infrared attenuating agent, lubricant, UV absorber, and process aid. The inventive foam composition produces extruded foams that have R-values that are equal to or better than conventional extruded foams produced with 1-chloro-1,1-difluoroethane (HCFC-142b). The foamed products are desirably made by a conventional extrusion process.
摘要:
Disclosed is a method for making polystyrene foam which utilizes one or more atmospheric gases, particularly combinations of HFCs and CO2, as the blowing system in combination with a polymer processing aid (PPA), typically an ester that is relatively non-volatile at the extrusion temperature range. The blowing system and the PPA may both be introduced into the molten thermoplastic polystyrene resin or the PPA may be incorporated in the solid source polystyrene resins. The resulting foams will typically exhibit improved dimensional stability at ambient temperatures.
摘要:
Polymeric foam and polymeric foam products that contain a foamable polymer material, at least one blowing agent, a polystyrene/polyethylene oxide copolymer, and optionally, an infrared attenuating agent, are provided. In exemplary embodiments, the blowing agent includes at least one hydrofluorocarbon blowing agent. The maleic anhydride-styrene copolymer grafted with polyethylene oxide provides a water vapor permeability of 1.1 perm inch or greater in the extruded foam product without detrimentally affecting physical or thermal properties of the product. Additionally, the copolymer of maleic anhydride-styrene grafted with polyethylene oxide has a positive affect on the processability of the blowing agent(s) in the composition by both widening the process window and enhancing the solubility of the blowing agent in the polymer melt. Thus, the polystyrene/polyethylene oxide copolymer present in the inventive composition acts as a cell enlarger, a plasticizer, and a processing aid. A method of forming an extruded foam product is also provided.
摘要:
Polymeric foam and polymeric foam products that contain a foamable polymer material, at least one blowing agent, a polystyrene/polyethylene oxide copolymer, and optionally, an infrared attenuating agent, are provided. In exemplary embodiments, the blowing agent includes at least one hydrofluorocarbon blowing agent. The maleic anhydride-styrene copolymer grafted with polyethylene oxide provides a water vapor permeability of 1.1 perm inch or greater in the extruded foam product without detrimentally affecting physical or thermal properties of the product. Additionally, the copolymer of maleic anhydride-styrene grafted with polyethylene oxide has a positive affect on the processability of the blowing agent(s) in the composition by both widening the process window and enhancing the solubility of the blowing agent in the polymer melt. Thus, the polystyrene/polyethylene oxide copolymer present in the inventive composition acts as a cell enlarger, a plasticizer, and a processing aid. A method of forming an extruded foam product is also provided.
摘要:
Polymeric foam and polymeric foam products that contain a foamable polymer material, at least one blowing agent, a polystyrene/polyethylene oxide copolymer, and optionally, an infrared attenuating agent, are provided. In exemplary embodiments, the blowing agent includes at least one hydrofluorocarbon blowing agent. The maleic anhydride-styrene copolymer grafted with polyethylene oxide provides a water vapor permeability of 1.1 perm inch or greater in the extruded foam product without detrimentally affecting physical or thermal properties of the product. Additionally, the copolymer of maleic anhydride-styrene grafted with polyethylene oxide has a positive affect on the processability of the blowing agent(s) in the composition by both widening the process window and enhancing the solubility of the blowing agent in the polymer melt. Thus, the polystyrene/polyethylene oxide copolymer present in the inventive composition acts as a cell enlarger, a plasticizer, and a processing aid. A method of forming an extruded foam product is also provided.
摘要:
Polymeric foam and polymeric foam products that contain a foamable polymer material, at least one hydrofluorocarbon (HFC) blowing agent, an infrared attenuating agent such as nanographite, and propylene carbonate, ethylene carbonate, or butylene carbonate as a process additive are provided. In one or more embodiments, the HFC blowing agent is 1,1-difluoroethane (HFC-152a), 1,1,1,2-tetrafluoroethane (HFC-134a), or a combination of 1,1-difluoroethane (HFC-152a) and 1,1,1,2-tetrafluoroethane (HFC-134a). The propylene carbonate, ethylene carbonate, or butylene carbonate acts as a cell enlarger to increase the average cell size of the foamed product, as a process aid, as a plasticizer, and lowers the die pressure. The inventive foam composition produces extruded foams that have insulation values (R-values) that are equal to or better than conventional extruded, closed cell foams produced with 1-chloro-1,1-difluoroethane (HCFC-142b). In exemplary embodiments, less than 4% of the cells are open cells. A method of forming an extruded foam product is also provided.
摘要:
In one embodiment, the present invention relates to a process for preparing foam board or sheet including the steps of (A) forming a foamable mixture of (1) a major amount of a styrenic polymer having a high melt index, (2) a minor amount of a low melt index styrenic polymer, and (3) a blowing agent containing a major amount of carbon dioxide under a pressure sufficient to prevent prefoaming of the mixture, and (B) foaming the mixture into a region of reduced pressure to form a foam product.
摘要:
In one embodiment, the present invention relates to a process for preparing a foam product including the steps of (A) forming a foamable mixture of (1) an alkenyl aromatic polymer and (2) a blowing agent under a pressure sufficient to prevent prefoaming of the mixture and (B) foaming the mixture into a region of reduced pressure to form the foam product, wherein the difference between the glass transition temperature of the foamable mixture and the foaming temperature is less than about 62.degree. C.