METHOD FOR THE IMPROVEMENT OF YIELD AND FREENESS IN THE PAPER-MAKING PROCESS AND THE WASTE WATER TREATING PROCESS, AND SULFONATED PHENOL-FORMALDEHYDE RESIN FOR PAPER-MAKING USED IN SAID METHOD

摘要

A method for the improvement of yield and freeness which does not discolor the paper product and gives a long life to the product and exerts stable yield improving effect even for the paper stuff containing much deinked pulp and filler as well as a yield improving promotor used in this method are provided. In the method for the improvement of yield and freeness in the paper-making process and the waste water treating process according to the present invention, a special phenol resin is used in combination with polyethylene oxide ( PEO ). The phenol resin of the present invention is a sulfonated phenol-formaldehyde resin synthesized by sulfonating a phenol and then condensing it with formaldehyde. Preferred as the phenol to be sulfonated are Bisphenol A and Bisphenol S. By using the method of the present invention, the yields of fine fiber and filler can be improved and the paper stuffs can be saved and the waste water treating load can be decreased.