Patent ID: 6274001
Filing Date: 2001-08-14
Classification: D21G

Abstract:
A method for temperature gradient calendering of a web of fibers, comprising the steps of:continuously applying surface sizing to a first side of an advancing web;continuously applying lubricant to said first side of the web;drying the web after surface sizing;applying moisture to said first side of the web after drying, the amount of moisture addition being in the range of 0.05-4% by weight;smoothening said first side by calendering the moisturized and lubricated web in a pressure nip formed in part by a first heated calender roll having a surface temperature in the range of 250-400.degree. F., said surface of said first heated calender roll contacting said first side of the web, and said pressure nip having a nipload in the range from 100 to 1,500 pli,wherein the dwell time for the web after moisturization and before said pressure nip is 0.01-6 sec, and said lubricant has the property of preventing sticking and picking of surface sizing and web fibers to said first heated calender roll.