To enhance the thermal insulation of polymeric foam by reducing cell anisotropic ratio and the method for production thereof
AssigneeOwens Corning Intellectual Capital, LLC
InventorsLarry M. Miller, Raymond M. Breindel, Mitchell Z. Weekley, Thomas E. Cisar
Life of this patent
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Abstract
This invention relates to foam insulating products, particularly extruded polystyrene foam, with increasing the cell orientation and reducing cell anisotropic ratio, as well as the process method for making the products thereof for improving the insulating properties and for reducing the manufacturing cost of the foam products. Alternatively, foam insulating products having increased cell compressive strength may be made by decreasing the cell orientation and increasing the cell anisotropic ratio.
Claims20
A method of increasing the cell orientation ratio in the x/z direction of a rigid polymer foam material comprising:
- providing a device capable of producing a rigid polymer foam material;
- introducing a thermoplastic polymer resin to said device;
- heating said thermoplastic polymer resin above its glass transition temperature and melting point;
- incorporating one or more blowing agents into said thermoplastic polymer resin at a first pressure to form a gel, said first pressure being sufficient to prevent pre-foaming of said gel;
- cooling said gel to a die melt temperature;
- and
- extruding the gel through a die gap of the device to a region of lower die pressure;
- wherein said gel is extruded through said die gap onto a conveyor such that the gel grows quicker in the x-direction relative to the z-direction to form the polymer foam material, wherein said x-direction is defined as the extruded direction of the polymer foam material and wherein said z-direction is defined as the vertical thickness direction of the polymer foam material
- wherein the polymeric foam material comprises greater than about 95% closed cells.
A method of improving the material properties of a rigid polymeric foam board suitable for use in building construction, comprising the steps of:
- heating a thermoplastic polymer resin above its glass transition temperature and melting point;
- incorporating one or more blowing agents into said thermoplastic polymer resin at a first pressure to form a gel, said first pressure sufficient to prevent pre-foaming of said gel;
- cooling said gel to a die melt temperature;
- extruding the gel into a region of lower pressure through a die gap onto a conveyor;
- pre-selecting the size of the die gap and the line speed of the conveyor, thereby controlling the rate at which the gel grows in the x-direction relative to the rate at which the gel grows in the z-direction,
- wherein said x-direction is defined as the extruded direction of the rigid polymeric foam board and wherein said z-direction is defined as the vertical thickness direction of the rigid polymeric foam board, and
- wherein the rigid polymeric foam board comprises greater than about 95% closed cells.
Dependencies are inferred from the claim text.