04726989 is referenced by 215 patents and cites 32 patents.

The present invention relates to microporous materials incorporating a nucleating agent and methods for making the same. The method comprises the steps of melt blending a crystallizable thermoplastic polymer with a nucleating agent which is capable of inducing subsequent crystallization of the thermoplastic polymer and with a compound which is miscible with the thermoplastic polymer at the melting temperature of the polymer but phase separates on cooling at or below the crystallization temperature of the polymer, forming a shaped article of the melt blend, cooling the shaped article to a temperature at which the nucleating agent induces the thermoplastic polymer to crystallize so as to cause phase separation to occur between the thermoplastic polymer and the compound, thereby providing an article comprising an aggregate of a first phase comprising particles of crystallized thermoplastic polymer in a second phase of the compound, and stretching the article in at least one direction to provide a network of interconnected micropores throughout. Preferably, the compound is removed either before or after stretching. The use of a nucleating agent in accordance with the present invention provides for the manufacture of a wide variety of microporous materials heretofore not possible having a wide range of porosity and other physical characteristics.

Microporous materials incorporating a nucleating agent and methods for making same
Application Number
Publication Number
Application Date
December 11, 1986
Publication Date
February 23, 1988
James S Mrozinski
Dale E Hulse
James A Smith
Donald M Sell
Minnesota Mining and Manufacturing
B32B 3/10
B29D 27/04
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