摘要:
Paper and cardboard are produced by draining a paper stock by a method in which a stock having a consistency of from 2.5 to 5% by weight is used as a starting material, and (a) from 0.1 to 2% by weight of an activated bentonite are added and the stock consistency is then brought to 0.3-2% by weight by dilution with water, after which (b) from 0.01 to 0.1% by weight of a cationic polyelectrolyte having a charge density of not less than 4 meq/g of polyelectrolyte is added and distributed therein, and, after thorough mixing (c) from 0.003 to 0.3% by weight of a high molecular weight polymer based on acrylamide or methacrylamide is metered in and mixed with the paper stock, the percentages in each case being based on dry paper stock, and the resulting pulp is drained on a wire. The paper obtained is distinguished in particular by good printing properties in the offset printing process.
摘要:
A process for removing anionic compounds from water which is recycled in manufacturing processes, and from waste water, by adding (1) water-soluble products obtained by reacting an alkylating agent, having an aromatic substituent, with a cationic polyelectrolyte and (2) mineral adsorbents and/or a magnesium salt, aluminum salt or iron salt, with formation and flocculation of water-insoluble reaction products.
摘要:
Aqueous pigment slurries which contain up to 80% by weight of a finely divided pigment in dispersed form and from 0.1 to 5% by weight of a water-soluble reaction product of (a) a polyamidoamine grafted with ethyleneimine and (b) a bifunctional or polyfunctional crosslinking agents which have a halohydrin, glycidyl, aziridine or isocyanate unit or a halogen atom as a functional group, the reaction product, in 25% strength by weight aqueous solution at 20.degree. C., having a viscosity of at least 100 mPa.s, are used as an additive to the paper stock in the production of filler-containing paper.
摘要:
Paper, board and cardboard are produced by draining a paper stock, containing undesirable substances, in the presence of hydrolyzed homo- and/or copolymers of N-vinylformamide having a degree of hydrolysis of not less than 60% and a cationic retention aid. According to the invention, faster drainage and improved retention are obtained compared with the use of known fixing agents.
摘要:
Paper, board and cardboard are produced by draining a pulp slurry in the presence of high molecular weight, water-soluble polymers of N-vinylamides as drainage aids, retention agents and flocculants. These polymers are particularly effective in a pulp slurry which has a high content of interfering substances and other phenolic compounds.
摘要:
Paper, board and cardboard are produced from paper stocks which contain tacky impurities by the addition of surfactants and cationic polymers having a charge density of at least 1.5 meq/g (measured at pH 7) and a molar mass Mw of the cationic polymers of at least 15,000 and drainage of the paper stocks with fixation of the tacky impurities in the paper produced.
摘要:
Paper and cardboard are produced by draining pulps, with sheet formation and drying of the sheets, by a process in which first(a) polyethyleneimines having a molar mass M.sub.w of more than 500,000 or polymers containing vinylamine units and having a molar mass of from 5000 to 3 million and then(b) cationic polyacrylamides or polymers containing vinylamine units, the molar masses M.sub.w of the polymers each being at least 4 million,are added to the pulps, and the pulp is then subjected to at least one shearing stage and is flocculated by adding bentonite, colloidal silica or clay.
摘要:
Stable water-in-oil emulsions of a hydrolyzed polymer of an N-vinylamide of the formula ##STR1## where R and R.sup.1 are each H or C.sub.1 -C.sub.6 -alkyl, are prepared by polymerizing a compound of the formula I, alone or as a mixture with other monoethylenically unsaturated monomers, in the form of a water-in-oil emulsion to give a water-in-oil polymer emulsion, and then hydrolyzing the polymer, hydrolysis of the polymer in the form of the water-in-oil polymer emulsion being carried out in the presence of an acid or base, and additives in the form of antioxidants, reducing agents or aldehyde acceptors being added for stabilization.
摘要:
Paper having a high dry strength is made using water-soluble homopolymers of salts or quaternary 1-vinyl-2-imidazolines and copolymers of these salts or quaternary compounds with acrylamide and/or methacrylamide as agents for increasing the dry strength of paper.