Patent ID: 11926968
Assignee: KURITA WATER INDUSTRIES LTD.
Field: Chemical engineering (Chemistry)
Classification: CPC D  B  C  Y | IPC B  C  D

Claim 0:
1. A method for producing paper comprising a step of adding a polymer having a polyalkylene oxide moiety to papermaking process water containing a suspended solid containing a papermaking raw material and unfixed starch,
wherein a proportion of the polyalkylene oxide moiety contained in the polymer is 50% by weight or more relative to the total polymer,
a concentration of the suspended solid contained in the papermaking process water is 100 mg/L or more,
a concentration of the unfixed starch contained in the papermaking process water is 10 mg/L or more, and
a salt viscosity of the polymer measured by the following method is 3 mPa·s or more,
the viscosity of an aqueous solution containing 4% by weight of common salt and 0.5% by weight of the polymer is measured under the conditions of 25° C. and a rotor rotating speed of 60 rpm; the viscosity measurement method is based on JIS K 7117-2.