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Assignee3M Innovative Properties Company
InventorsJayshree Seth, Christopher K. Haas, Ravi K. Sura, Katherine A. S. Graham, Janet A. Venne
Estimating the term…
The invention is directed in part to an article that includes a polymer foam having a surface with surface microstructures, the surface microstructures have at least one extent or dimension of about 10 microns or more, preferably 50 microns or more. A maximum extent (unless it is a continuous rib-like structure) the microstructure is about 300 microns or less, preferably 200 microns or less, and generally a maximum height of 1000 microns or less, preferably 750 microns or less and a minimum height of 200 microns or more, preferably 300 microns or more. The foamed article may be provided in a variety of shapes, including a rod, a cylinder, a sheet, etc. In a preferred embodiment where the foam is provided in the form of a sheet, the foam has a pair of major surfaces, one or both of which can be provided with surface microstructures. The foam backing and microstructures include a plurality of voids, which voids are preferably of a mean size substantially less than the smallest cross-sectional dimension or extent of the microstructures.
An article comprising a base layer made of thermoplastic polymer having at least one outer face, said outer face containing over at least one area a plurality of foamed hook shaped microstructures comprised of multiple discrete foam cells, the foamed hook shaped microstructures comprising a semicrystalline thermoplastic polymer, the foamed hook shaped microstructures having at least one dimension which is greater than 10 microns and the discrete foam cells forming the foamed hook shaped microstructures having a mean cell size less than the smallest cross-sectional dimension of the foamed hook shaped microstructures excluding any tips on the foamed hook shaped microstructures and measured at a distance of at least 10 microns from such tips, wherein the smallest cross-sectional dimension of the foamed hook shaped microstructures is a width or thickness dimension and is about 50 microns or more, the foamed hook shaped microstructures have heights of generally 1000 microns or less, the ratio of the mean cell size of the discrete foam cells to the smallest cross-sectional dimension of the foamed hook shaped microstructures is 0.75 or less, the semicrystalline thermoplastic polymer is at least in part a high melt strength polypropylene having a melt strength in the range of 25 to 60 cN at 190° C. and the base layer is oriented in at least one direction.
Dependencies are inferred from the claim text.