| 摘要 |
1. A paper furnish containing: (a) a soluble aluminum compound present in the amount of approximately 0.005 to 2.5 kilograms of A12O3 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 proviso that: (i) cooking is conducted at a pH above 7.0 in the case that a cationic or nonionic polyacrylamide is selected; (ii) cooking produces no more than 75% neutralizing of the cationic starch in the case that molecular weight of anionic polyacrylamide is in between of from 500,000 to 4,000,000 and not more than 50% neutralizing of the cationic starch if molecular weight of anionic polyacrylamide is more than 4,000,000, and (iii) the weight ratio of starch to polyacrylamide is greater than about 2 to 1. 2. The paper furnish of Claim 1 wherein a cationic starch is cooked with a cationic acrylamide. 3. The paper furnish of Claim 1 wherein a cationic starch is cooked with an anionic acrylamide. 4. The paper furnish of Claim 1, 2 or 3 wherein the soluble aluminum compound is added to the furnish prior to addition of the modified starch. 5. The paper furnish of Claim 1, 2 or 3 wherein the starch is selected from the group consisting of corn starch, potato starch, and waxy maize starch. 6. The paper furnish of Claim 1, 2 or 3 wherein a colloidial silicon dioxide is also present. 7. The paper furnish of Claim 1, 2 or 3 wherein an anionic inorganic colloid is also present. 8. The paper furnish of Claim 1, 2 or 3 wherein the soluble aluminum compound is selected from the group consisting of aluminum sulfate, aluminates, aluminum nitrate, polyaluminum chloride and polyaluminum sulfate. |
