10 by mass of the filler and gcc comprises at least 10 of the filler mass pre treating at least some of the filler particles with a coating that decreases the adhesion between a strength additive and the filler particles and adding both the filler blend and the strength additive to the paper mat it has been known for some time that adding strength additives to paper mat increases the strength of the resulting paper some examples of strength additives are described in u s pat no 4 605 702 some examples of strength additives are cationic starches which adhere to the cellulose fibers and tightly bind them together unfortunately it is not practical to add large amounts of strength additives to compensate for the weakness that results from using large amounts of filler in paper mat one reason is because strength additives are expensive and using large amounts of additives would result in production costs that are commercially non viable in addition adding too much strength additive negatively affects the process of papermaking and inhibits the operability of various forms of papermaking equipment as an example in the context of cationic starch strength additives the cationic starch retards the drainage and dewatering process which drastically slows down the papermaking process furthermore cellulose fibers can only adsorb a limited amount of strength additive this.