US2003136532A1PendingUtilityA1

Method for increasing filler retention of cellulosic fiber sheets

52
Assignee: WEYERHAEUSER COPriority: Mar 19, 1999Filed: Dec 20, 2002Published: Jul 24, 2003
Est. expiryMar 19, 2019(expired)· nominal 20-yr term from priority
Inventors:Richard A. JewellAmar N. NeogiSteven White
D21H 21/10D21H 17/455D21H 23/765D21H 17/68D21H 11/20D21H 17/29D21H 17/55D21H 17/675D21H 17/375
52
PatentIndex Score
0
Cited by
0
References
0
Claims

Abstract

A method for increasing filler retention of cellulosic fiber sheets is disclosed. In the method, cellulosic fibers with increased anionic sites are treated with either positively charged filler particles and/or amphoteric filler particles or a cationic retention aid and negatively charged filler particles and/or amphoteric filler particles. Cellulosic fiber sheets with retained filler particles are also disclosed.

Claims

exact text as granted — not AI-modified
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:  
     
         1 . A method for preparing a cellulosic fiber sheet having retained filler particles, comprising treating fibers having increased anionic sites with positively charged filler particles to provide a cellulosic fiber sheet having retained positively charged filler particles.  
     
     
         2 . The method of  claim 1  wherein fibers having increased anionic sites comprise carboxylated cellulosic fibers.  
     
     
         3 . The method of  claim 1  wherein the positively charged filler particles comprise calcium carbonate particles.  
     
     
         4 . A method for preparing a cellulosic fiber sheet having retained filler particles, comprising: 
 treating fibers having increased anionic sites with a cationic retention aid to provide cellulosic fibers having bonded cationic retention aid; and    treating the fibers having bonded cationic retention aid with negatively charged filler particles to provide a cellulosic fiber sheet having retained negatively charged filler particles.    
     
     
         5 . The method of  claim 4  wherein fibers having increased anionic sites comprise carboxylated cellulosic fibers.  
     
     
         6 . The method of  claim 4  wherein the cationic retention aid is selected from the group consisting of cationic polyacrylamides and cationic starches.  
     
     
         7 . The method of  claim 4  wherein the negatively charged filler particles are selected from the group consisting of ground limestone and clay particles.  
     
     
         8 . A method for preparing a cellulosic fiber sheet having retained filler particles, comprising: 
 combining a cationic retention aid with negatively charged filler particles; and    treating fibers having increased anionic sites with the combination of a cationic retention aid and negatively charged filler particles to provide a cellulosic fiber sheet having retained negatively charged filler particles.    
     
     
         9 . A cellulosic fiber sheet having retained filler particles, wherein the filler particles are bonded to fibers having increased anionic sites, wherein the filler particles are bonded to the fibers through the anionic sites, and wherein the filler particles are selected from the group consisting of positively charged filler particles, negatively charged filler particles, and amphoteric filler particles.  
     
     
         10 . A cellulosic fiber sheet having retained positively charged filler particles, wherein the filler particles are bonded to the fibers through anionic sites incorporated into the fibers.  
     
     
         11 . The sheet of  claim 10  wherein the anionic sites are carboxyl groups.  
     
     
         12 . The sheet of  claim 10  wherein the positively charged filler particles comprise calcium carbonate particles.  
     
     
         13 . A cellulosic fiber sheet having retained negatively charged filler particles, wherein the filler particles are bonded to the fibers through a cationic retention aid bonded to anionic sites incorporated into the fibers.  
     
     
         14 . The sheet of  claim 13  wherein the anionic sites are carboxyl groups.  
     
     
         15 . The sheet of  claim 13  wherein the cationic retention aid is selected from the group consisting of cationic polyacrylamides and cationic starches.  
     
     
         16 . The sheet of  claim 13  wherein the negatively charged filler particles are selected from the group consisting of ground limestone and clay particles.  
     
     
         17 . A cellulosic fiber sheet having retained negatively charged filler particles, wherein the filler particles are bonded to the fibers through a cationic retention aid bonded to the anionic sites incorporated into the fibers, wherein the fixed anionic sites comprise carboxyl groups, wherein the cationic retention aid comprises cationic polyacylamide, and wherein the negatively charged filler particles are selected from the group consisting of ground limestone and clay particles.  
     
     
         18 . A papermaking furnish comprising cellulosic fibers having increased anionic sites and positively charged filler particles, wherein the filler particles are bonded to the fibers through fixed anionic sites incorporated into the fibers.  
     
     
         19 . The furnish of  claim 18  wherein the fixed anionic sites are carboxyl groups.  
     
     
         20 . The furnish of  claim 18  wherein the positively charged filler particles comprise calcium carbonate particles.  
     
     
         21 . A papermaking furnish comprising cellulosic fibers having increased anionic sites and negatively charged filler particles, wherein the filler particles are bonded to the fibers through a cationic retention aid bonded to anionic sites incorporated into the fibers.  
     
     
         22 . The furnish of  claim 21  wherein the anionic sites are carboxyl groups.  
     
     
         23 . The furnish of  claim 21  wherein the cationic retention aid is selected from the group consisting of cationic polyacrylamides and cationic starches.  
     
     
         24 . The furnish of  claim 21  wherein the negatively charged filler particles are selected from the group consisting of ground limestone and clay particles.  
     
     
         25 . A method for increasing the drainage of water from a fibrous furnish deposited onto the forming wire of a papermaking machine, comprising incorporating into a fibrous furnish cellulosic fibers having increased anionic sites and positively charged filler particles, wherein the filler particles are bonded to the fibers through anionic sites incorporated into the fibers.  
     
     
         26 . A method for increasing the drainage of water from a fibrous furnish deposited onto the forming wire of a papermaking machine, comprising incorporating into a fibrous furnish cellulosic fibers having increased anionic sites and negatively charged filler particles, wherein the filler particles are bonded to the fibers through a cationic retention aid bonded to fixed anionic sites incorporated into the fibers.  
     
     
         27 . A method for increasing the drainage of water from a fibrous furnish deposited onto the forming wire of a papermaking machine, comprising incorporating into a fibrous furnish cellulosic fibers having increased anionic sites and a cationic material.  
     
     
         28 . The method of  claim 27  wherein the cellulosic fibers having increased anionic sites comprise carboxylated fibers.  
     
     
         29 . The method of  claim 27  wherein the cationic material comprises polyamide epichlorohydrin.

Join the waitlist — get patent alerts

Track US2003136532A1 — get alerts on status changes and closely related new filings.

We store only your email — no account needed. See our privacy policy.