Patent ID: 6013222
Filing Date: 2000-01-11
Classification: B24D,B29C,B29K

Abstract:
A method of producing sheet material having abrasive particles retained in an outer surface thereof, the method comprising:(a) supplying polymer to an inlet of a blown film die, and adding the abrasive particles to only a part of the polymer supplied to the die inlet to form a composite material comprising polymer with the abrasive particles present in only a part thereof;(b) extruding the composite material through the die to form an extrudate having an inner portion of polymer without abrasive particles and an outer portion of a mixture of polymer and abrasive particles;(c) expanding the extrudate to form a blown polymeric film in which the abrasive particles are present in only the outer portion of the thickness of the film wherein, as the extrudate is expanded to form the blown polymeric film, the abrasive particles in the outer portion become increasely exposed with some abrasive particles breaking through the outer surface of the film and other abrasive particles remaining covered by only a very thin layer of polymer.