JP2895248B
Paper, pasteboard and cardboard (I) are produced by draining off pulp contg. interfering substances in the presence of fixing agents (II) and cationic retention agents; the novelty is that (II) are hydrolysed homo- and/or co-polymers of N-vinylformamide (III) with degree of hydrolysis (DH) at least....
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Format: | Patent |
Sprache: | eng |
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Zusammenfassung: | Paper, pasteboard and cardboard (I) are produced by draining off pulp contg. interfering substances in the presence of fixing agents (II) and cationic retention agents; the novelty is that (II) are hydrolysed homo- and/or co-polymers of N-vinylformamide (III) with degree of hydrolysis (DH) at least. 60%. (II) has DH 70-100%; (II) are hydrolysed copolymers of (III) and up to 90 mol.% unsatd. comonomers, namely vinyl acetate or propionate, 1-4C alkyl vinyl ether, N-vinyl-pyrrolidone, or esters, nitriles or amides of (meth)acrylic acid, with DH = 70-100%; pref. (II) are obtd. by polymerisation of 100-10 mol.% (III) and 0-90 mol.% vinyl acetate and/or propionate, followed by cleavage of 60-100% of the formyl gps., and 60-100% of the acetyl and/or propionyl gps. |
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