A method for creating random shadow patterns in formed vinyl sheet to be used as siding material for buildings. The method includes the step of extruding a flat, hot web of vinyl material having a predetermined thickness and a predetermined distance between the edges thereof, then embossing a graining...http://www.google.es/patents/US4352771?utm_source=gb-gplus-sharePatente US4352771 - Method and apparatus for creating random shadow patterns in formed vinyl sheet article
Method and apparatus for creating random shadow patterns in formed vinyl ...
