摘要:
IMPROVED QUALITY IS IMPARTED TO FIBROUS WEB MATERIALS USED AS BASE STOCK FOR SATURATING AND COATING APPLICATIONS BY EMPLOYING PRODUCTION CONDITIONS THAT ELIMINATE NONUNIFORM AND PREFERENTIAL SHRINKAGE AND THE TENDENCY OF THE OPEN FIBROUS WEBS TO DEVELOP DISCRETE STRESS AREAS IN THE FORM OF COCKLES AND PUCKERS. THE PROCESS HAS PARTICULAR ADVANTAGE FOR BASE STOCK OF LOW DENSIMETER VALUE, SUCH AS A VALUE OF LESS THAN 1 SEC./100 ML. AND PREFERABLY LESS THAN 0.1 SEC./100 ML., AS MEASURED BY TAPPI TEST METHOD T 460 OS-68 AND INVOLVES THE PERCOLATION OF GASES THROUGH THE WET WEB MATERIAL AS IT IS HELD BY THE GASES IN A RESTRAINED CONDITION ON A SINGLE FORAMINOUS SUPPORT DURING DRYING UNTIL ITS MOISTURE CONTENT IS REDUCED TO A LEVEL OF ABOUT 8 PERCENT BY WEIGHT AND LWSS.