Abstract:
Disclosed herein is a process for producing polymers of an N-vinyl carboxamide, including the steps of flowing a reaction mixture containing an aqueous liquid containing at least one polymerisation initiator, N-vinyl carboxamide monomer or a monomer mixture containing N-vinyl carboxamide into a reactor system, and polymerising the monomer or monomer mixture to produce the polymer of a N-vinyl carboxamide. The polymers resulting therefrom may be hydrolysed to provide polymers containing vinyl amine units. Also disclosed herein is an apparatus suitable for producing the polymers.
Abstract:
A process for producing paper or board, which process comprises ad-mixing (I) an aqueous composition of pH ≦6 and (II) at least one water-soluble polymeric anionic compound to a paper stock having a pH in the range from 6 to 8 and then dewatering the paper stock by sheet formation and drying, wherein the aqueous composition comprises (a) polymers having primary amino groups and/or amidine groups to a combined content for these groups of ≧1.5 meq/g of polymer, and (b) 0.01 to 50 mol % of 1,4-cyclohexanedione (b) based on the combined amount of primary amino groups and/or amidine groups of the polymers, and also to the paper or board thus obtained.
Abstract:
The invention relates to an aqueous composition comprising (a) polymers having primary amino groups and/or amidine groups to a combined content for these groups of ≧1.5 meq/g of polymer, and (b) 0.01 to 50 mol % of 1,4-cyclohexanedione (b) based on the combined amount of primary amino groups and amidine groups of the polymers, wherein the pH of the aqueous composition is ≦6, and further to its use as strength enhancer and to a method of producing paper and board, employment of the aqueous composition and also the paper and board thus obtained.
Abstract:
The present invention relates to a process for production of paper, card and board comprising draining a filler-containing paper stock comprising at least one water-soluble polymer with sheet formation in the wire section and then pressing the paper in the press section, wherein a paper stock having a fibrous concentration in the range from 20 to 40 g/l has the at least one water-soluble polymer added to it, then the paper stock is diluted to a fibrous concentration in the range from 5 to 15 g/l, the diluted paper stock is drained to form a sheet and the sheet is pressed in the press section to a solids content G(x) wt % or greater and G(x) computes according to G(x)=48+(x−15)·0.4 where x is the numerical value of the filler content of the dry paper, card or board (in wt %) and G(x) is the numerical value of the minimum solids content (in wt %) to which the sheet is pressed, wherein the water-soluble polymer is obtainable by Hofmann degradation of an acrylamide- and/or methacrylamide-containing polymer with or without subsequent postcrosslinking.
Abstract:
A method of producing paper and board by using at least one water-soluble amphoteric polymer is provided. The water-soluble amphoteric polymer is obtained by copolymerizing a monomer mixture containing a) at least one N-vinylcarboxamide, b) at least one monoethylenically unsaturated monomer having at least one free acid group or at least one acid group in salt form, c) optionally at least one monoethylenically unsaturated monomer other than components (a) and (b), and d) optionally at least one compound having two or more ethylenically unsaturated double bonds, and then partly or wholly hydrolyzing the —CO—R1 groups of the polymer. The cationic monomer units and the anionic monomer units differ in their respective molar fractions, each based on the total number of moles of all monomer units, by not more than 10 mol % in absolute terms.
Abstract:
Graft polymers whose grafting base is selected from the group consisting of polymers having vinylamine units, polyamines, polyamidoamines and polymers of ethylenically unsaturated acids and which comprise exclusively oligoalkylenimine side chains as side chains, process for the preparation of graft polymers having oligoalkylenimine side chains, at least one oligoalkylenimine which comprises a terminal aziridine group being grafted onto one of said grafting bases, and the use of the graft polymers thus obtainable as process chemicals in the production of paper, as antimicrobial coating materials, as builders in detergents and for the treatment of metal surfaces.