The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 23, 2001
Filed:
Jan. 04, 2000
Bo Rosengren, Ljungbyhed, SE;
Ulla Gytel, Helsingborg, SE;
Kemira Kemi AB, Helsingborg, SE;
Abstract
A method and an agent for improving the retention when dewatering a cellulosic fiber suspension are disclosed In the method, there is added to the suspension a retention agent containing a phenol-formaldehyde resin and a polyethylene oxide, and the method is characterised in that a modified phenol-formaldehyde resin containing cationic groups is added to the suspension. The modified phenol-formaldehyde resin preferably has a cationicity of about 5-85% and the cationic groups preferably consist of amine groups. The polyethylene oxide in the retention agent preferably has a molecular weight of about 0.5-20×10,. The modified phenol-formaldehyde resin and the polyethylene oxide are preferably added to the suspension in a weight ratio of modified phenol-formaldehyde resin:polyethylene oxide of from 1:5 to 50:1, and the amount of polyethylene oxide added preferably is about 10-1000 ppm, based on tie dry solids content of the suspension. Preferably first the modified phenol-formaldehyde resin is added to the suspension and then the polyethylene oxide.