An improved binder for use in paper-making contains three ingredients, a cationic starch having a degree of substitution of at least 0.01, a high molecular weight anionic polymer having a molecular weight of at least 500,000 and a degree of anionic substitution of at least 0.01, and a dispersed silica...http://www.google.com.tw/patents/US4643801?utm_source=gb-gplus-share專利 US4643801 - Papermaking aid
