| 摘要 |
<p>It is described an aqueous suspension of a stuff for paper production containing: (a) a soluble aluminium compound, present in the amount of 0.005 to 2.5 kilograms of Al2O3 per metric ton of dry paper, and (b) a modified starch prepared by cooking an aqueous solution of at least one amphoteric or cationic starch having a degree of substitution between about 0.01 to 0.2 with at least one nonionic or amphoteric polyacrylamide, or cationic or anionic polyacrylamide having a degree of substitution between 1% and 80% by weight, having a molecular weight of at least 500,000, with the provisos that (i) cooking is conducted at a pH above 7.0 in the case that a cationic or non-ionic polyacrylamide is selected; (ii) cooking produces no more than 75% neutralization of the cationic starch in the case that an amphoteric polyacrylamide is selected, (iii) in the case that an anionic polyacrylamide is selected, cooking produces no more than 75% neutralization of the cationic starch if the anionic polyacrylamide molecular weight is low and cooking produces no more than 50% neutralization of the cationic starch if the anionic polyacrylamide molecular weight is high, and (iv) the weight ratio of starch to polyacrylamide is greater than 2 to 1.</p> |
