Method of extruding thermoplastic resin foams having enlarged cell-sizes
First Claim
1. A process for the preparation of a synthetic resinous thermoplastic extruded foam wherein a heat-plastified synthetic resinous gel containing a volatile fluid foaming agent, the gel being at a foaming temperature, the gel at the foaming temperature being expressed from a die into a region of reduced pressure, the reduced pressure being sufficient to permit the gel to expand into cellular form and cooling the gel to a temperature at which the gel is self-supporting, the improvement which comprises incorporating within the heat-plastified unfoamed gel, a cell-size enlarging agent, the cell-size enlarging agent being an organic compound which is liquid at the foaming temperature and atmospheric pressure and generally soluble in the gel at the foaming temperature, the cell-size enlarging agent being present in an amount of from about 0.01 to 5 parts by weight per hundred based on the weight of the thermoplastic resin in the foamable gel.
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Abstract
Extruded synthetic resinous thermoplastic foams of increased cell size are obtained when using volatile fluid blowing agents by incorporating a cell-size enlarging agent into the extruded composition, the cell-size enlarging agent being liquid at the foaming temperature and generally soluble in the heat-plastified foamable mixture.
51 Citations
6 Claims
- 1. A process for the preparation of a synthetic resinous thermoplastic extruded foam wherein a heat-plastified synthetic resinous gel containing a volatile fluid foaming agent, the gel being at a foaming temperature, the gel at the foaming temperature being expressed from a die into a region of reduced pressure, the reduced pressure being sufficient to permit the gel to expand into cellular form and cooling the gel to a temperature at which the gel is self-supporting, the improvement which comprises incorporating within the heat-plastified unfoamed gel, a cell-size enlarging agent, the cell-size enlarging agent being an organic compound which is liquid at the foaming temperature and atmospheric pressure and generally soluble in the gel at the foaming temperature, the cell-size enlarging agent being present in an amount of from about 0.01 to 5 parts by weight per hundred based on the weight of the thermoplastic resin in the foamable gel.
Specification
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- Resources
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Current AssigneeThe Dow Chemical Company (Dow, Inc.)
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Original AssigneeThe Dow Chemical Company (Dow, Inc.)
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InventorsSuh, Kyung W., Amos, Charles R.
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Primary Examiner(s)Anderson, Philip
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Application NumberUS06/022,579Time in Patent Office580 DaysField of Search264/53, 264/DIG. 13, 264/211, 521/79, 521/82, 521/98US Class Current264/53CPC Class CodesC08J 2491/00 Characterised by the use of...C08J 9/0061 characterized by the use of...Y10S 264/13 Cell size and distribution ...
