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US 4,708,891 AGranted
Method for manufacturing polishing cloths
AssigneeToyo Cloth Co., Ltd.
InventorsHajime Ito, Junichi Miwa
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Abstract
A method for manufacturing polishing cloths of the class to be used with abrasive powders on a lapping machine is disclosed. The method comprises the steps of impregnating a nonwoven fabric sheet with a solution of polyurethane elastomer, wet-coagulating the impregnated sheet, and heating the resulting microporous composite sheet at a temperature higher than the softening point of the polyurethane elastomer under an essentially uncompressed condition.
Claims6
A method for producing a polyurethane-based polishing cloth which comprises the steps of:
- impregnating, with a solution containing a polyurethane elastomer, a nonwoven fabric sheet made of a synthetic fiber having a melting point higher than that of said polyurethane elastomer;
- wet-coagulating the resulting impregnated sheet to form a microporous composite sheet;
- and
- heating the resulting composite sheet in an essentially uncompressed condition at a temperature higher than the softening point of the polyurethane elastomer and lower than the melting point of the synthetic fiber for a sufficient length of time to impart to the sheet a degree of hardness greater than 80 and an air-permeability greater than 25 cc/cm.sup.2 /second.
1 more element
Dependencies are inferred from the claim text.