公开(公告)号：US3832267A

公开(公告)日：1974-08-27

申请号：US29030972

申请日：1972-09-19

申请人： HERCULES INC

发明人： LIU C

IPC分类号： B29C43/00 ,  A61F13/00 ,  A61F13/15 ,  A61F13/20 ,  A61F15/00 ,  B29C33/00 ,  B29C49/00 ,  B29C55/00 ,  B29C55/12 ,  B29C59/00 ,  B29C59/02 ,  B29C59/04 ,  B29D28/00 ,  C08L23/02

CPC分类号： B29C59/022 ,  A61F13/00017 ,  A61F13/51104 ,  A61F13/51476 ,  A61F13/551 ,  A61F2013/15048 ,  A61F2013/51078 ,  A61F2013/51409 ,  A61F2013/51411 ,  B29K2023/12 ,  B29K2995/0053 ,  Y10T428/24165 ,  Y10T428/24479 ,  Y10T428/2457

摘要： EMBOSSED, BIAXIALLY ORIENTED PROPYLENE POLYMER FILMS HAVING GREAT TEAR STRENGTH FOR THEIR THICKNESS CAN BE PREPARED IF CERTAIN CRITICAL LIMITATIONS ARE FOLLOWED. THE PROCESS COMPRISES EMBOSSING A SHEET OF PROPYLENE POLYMER HAVING A CRYSTALLINITY OF FROM ABOUT 40% TO 65% AND CONTAINING AT LEAST 80% OF REPEATING UNITS DERIVED FROM PROPYLENE MONOMER TO A DEPTH OF FROM ABOUT 50% TO 75% OF ITS THICKNESS WITH AT LEAST 4 BUT NO MORE THAN 600 UNIFORM RAISED BOSSES PER SQUARE INCH, EACH BOSS ENCLOSED BY A RAISED LIP, THE VALLEY AREAS SEPARATING INDIVIDUAL BOSSES CONSTITUTING FROM ABOUT 20% TO 40% OF THE SURFACE OF THE EMBOSSED FILM AND SUBJECTING THE THUS EMBOSSED FILM TO BIAXIAL DRAWING OF AT LEAST 2.5 TO 5.0 TIMES IN BOTH THE MACHINE AND CROSS-MACHINE DIRECTIONS.