Process for making high-strength, high-yield sulfite-modified thermomechanical pulp and a linerboard composition produced therefrom
CA 1080911 A · Owner: Crown Zellerbach Corporation · Inventors: Fahey, Michael D.; Goheen, David W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A high-strength, high-yield sulfite-modified thermomechanical pulp is formed by subjecting lignocellulose to multistage mechanical attrition, the first stage being conducted at elevated temperature and pressure and the second stage being run under atmospheric conditions. A sulfite chemical is added to the lignocellulose prior to the second stage, the lignocellulose being sulfonated so that a percent bound sulfur level of at least about 0.15% is provided. A novel linerboard composition is unexpectedly produced empoying replacement quantities of the above described pulp.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted July 8, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 8, 1997.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.