Abstract: A process for modifying starch by heating starch in an aqueous medium to temperatures above the gelatinization temperature of said starch comprises effecting said modifying of said starch in the presence of (a) a polymeric cationizer selected from the group consisting of the polymers containing vinylamine units and having molar masses of up to 1 million, the polyethyleneimines, the polydiallyldimethylammonium chlorides, the condensates of dimethylamine with epichlorohydrin or dichloroalkanes, the condensates of dichloroethane and ammonia, and the mixtures thereof, and (b) polymeric papermaking drainage aids selected from the group consisting of the water-soluble crosslinked polyamidoamines with or without an ethyleneimine graft, the polymers containing acrylamide and/or methacrylamide units and having molar masses of more than 1 million, the polymers containing vinylamine units and having molar masses of more then 1 million, and the mixtures thereof.

Abstract: According to the present disclosure, starch/polymer combinations are provided. The preferred starch/polymer combinations are usable as paper additives, in the wet end of a papermaking process. Typical and preferred starch/polymer combinations of this type, result from combining a starch, having a polymer reactive carbonyl functionality, with a polymer, having a carbonyl reactive functionality, under conditions that allow for covalent interaction between the two. Typically usable components comprise oxidized starch and polymer having reactive primary or reactive secondary amine groups. Also provided are methods of preparing such combinations, methods of use, preferred papers including such combinations, and, analytical techniques usable in preparation of such combinations.

Abstract: Paper, board and cardboard having high dry strength are produced by the addition of cationic, anionic and/or amphoteric starch as dry strength agents to the paper stock and drainage of the paper stock with sheet formation in the presence of cationic polymers as retention aids for starch, and cationic polymeric retention aids are used for increasing the retention of dry strength agents comprising cationic, anionic and/or amphoteric starch in the production of paper, board and cardboard.

Abstract: According to the present disclosure, starch/polymer combinations are provided. The preferred starch/polymer combinations are usable as paper additives, in the wet end of a papermaking process. Typical and preferred starch/polymer combinations of this type, result from combining a starch, having a polymer reactive carbonyl functionality, with a polymer, having a carbonyl reactive functionality, under conditions that allow for covalent interaction between the two. Typically usable components comprise oxidized starch and polymer having reactive primary or reactive secondary amine groups. Also provided are methods of preparing such combinations, methods of use, preferred papers including such combinations, and, analytical techniques usable in preparation of such combinations.

Abstract: Solutions of polymers containing vinylamine units, which solutions have a long shelf life, are prepared by hydrolyzing polymers containing N-vinylcarboxamide units with acids in an aqueous medium and removing the carboxylic acids eliminated from the polymers as esters from the aqueous polymer solution after the hydrolysis by adding at least stoichiometric amounts of at least one C.sub.1 -C.sub.6 -alcohol and distilling off the esters from the reaction mixture, and said aqueous solutions are used as dry and wet strength agents in papermaking.

Abstract: Graft polymers are obtainable by free radical polymerization of(A) monomers or monomer mixtures comprising(a) from 1 to 100% by weight of N-vinylcarboxamides of the formula ##STR1## where R.sup.1 and R.sup.2 are each H or C.sub.1 -C.sub.6 -alkyl, (b) from 0 to 99% by weight of other monoethylenically unsaturated monomers copolymerizable with the monomers (a) and(c) from 0 to 5% by weight of monomers having at least two ethylenically unsaturated, nonconjugated double bonds in the molecule,in the presence of(B) polymers which contain units of vinyl esters of saturated C.sub.1 -C.sub.

Abstract: A graft polymer obtained by free radically polymerizing:(A) a monomer or monomer mixture comprising:(a) from 10-100% by weight of a N-vinylcarboxamide of the formula: ##STR1## where R.sup.1 and R.sup.2 are each H or C.sub.1 -C.sub.6 -alkyl, (b) from 0-90% by weight of at least one other monoethylenically unsaturated monomer which is copolymerizable with (a), and(c) from 0-5% by weight of at least one monomer having at least two ethylenically unsaturated nonconjugated double bonds in the molecule, in the presence of(B) a polytetrahydrofuran or a polymer which contains at least 3 units of a C.sub.2 -C.sub.4 alkylene oxide and is a hornopolymer of C.sub.2-4 -alkylene oxide having two free terminal OH groups or random or block copolymers of C.sub.2-4 -alkylene oxides having two free terminal OH groups or the reaction products of C.sub.

Abstract: In a cationic modification process for starch, starch is reacted with polymers that contain amino and/or ammonium groups in an aqueous medium at temperatures from 115.degree. C. to 180.degree. C. under an increased pressure and in the absence of oxidizers, polymerization initiators and alkali. The reaction is conducted so that maximum 10% by weight starch has its molar weight reduced. Also disclosed is the use of the thus obtained reaction products as dry strength agents for paper.

Abstract: Copolymers which are obtained by copolymerization ofa) from 5 to 99 mol % of N-vinylcarboxamides,b) from 95 to 1 mol % of monoethylenically unsaturated carboxylic acids and/or the alkali metal, alkaline earth metal, ammonium or amine salts thereof, and if required,c) up to 30 mol % of other monoethylenically unsaturated compounds, and if required,d) up to 2 mol % of crosslinking agents,and subsequent partial or complete elimination of the acyl groups from the N-vinylcarboxamides polymerized in the copolymer, with formation of amino or ammonium groups, are used as additives to paper stock for increasing the drainage rate and the retention in papermaking, and the dry and wet strength of the paper.

Abstract: Graft polymers are obtainable by free radical polymerization of(A) monomers or monomer mixtures of(a) from 10 to 100% by weight of open-chain N-vinylcarboxamides(b) from 0 to 90% by weight of other, carboxyl-free monoethylenically unsaturated monomers which are copolymerizable with the monomers (a) and(c) from 0 to 5% by weight of monomers containing two or more ethylenically unsaturated, non-conjugated double bonds in the molecule,in the presence of(B) natural substances containing saccharide structures, such as mono-, oligo- and polysaccharides,in a weight ratio (A):(B) of from 95:5 to 20:80 and, if required, subsequent hydrolysis of the amido groups of the polymerized monomers (a) of the graft polymer with formation of amino groups, and said polymers are used as dry and wet strength agents for paper, board and cardboard.

Abstract: Cationic urea/formaldehyde resins are obtainable by condensing urea and formaldehyde in a molar ratio of from 1:1.5 to 1:3 in the presence of polymers which contain not less than 1 mol % of polymerized vinylamine units and have Fikentscher K values of from 5 to 300, in an amount of from 5 to 50 g per mole of urea in the end product, where the mixture is first a) precondensed at a pH of from 8 to 14, then acidified and b) condensed at a pH of from 1 to 5 until gel formation begins, c) then from 0.3 to 1.5 moles of formaldehyde are added per mole of urea used, d) post-condensation is carried out and e) the resin solution is subsequently neutralized. The resins thus obtained are used in papermaking as assistants for increasing the dry and wet strength of paper and result in less dulling of the whiteness of the paper.

Abstract: Graft polymers are obtainable by free radical polymerization of(A) monomers or monomer mixtures of(a) from 10 to 100% by weight of open-chain N-vinylcarboxamides(b) from 0 to 90% by weight of other, carboxyl-free moneothylenically unsaturated monomers which are copolymerizable with the monomers (a) and(c) from 0 to 5% by weight of monomers containing two or more ethylenically unsaturated, non-conjugated double bonds in the molecule,in the presence of(B) natural substances containing saccharide structures, such as mono-, oligo- and polysaccharides,in a weight ratio (A):(B) of from 95:5 to 20:80 and, if required, subsequent hydrolysis of the amido groups of the polymerized monomers (a) of the graft polymer with formation of amino groups, and said polymers are used as dry and wet strength agents for paper, board and cardboard.

Abstract: Cationic urea/formaldehyde resins are obtainable by condensing urea and formaldehyde in a molar ratio of from 1:1.5 to 1:3 in the presence of polymers which contain not less than 1 mol % of polymerized vinylamine units and have Fikentscher K values of from 5 to 300, in an amount of from 5 to 50 g per mole of urea in the end product, where the mixture is first a) precondensed at a pH of from 8 to 14, then acidified and b) condensed at a pH of from 1 to 5 until gel formation begins, c) then from 0.3 to 1.5 moles of formaldehyde are added per mole of urea used, d) post-condensation is carried out and e) the resin solution is subsequently neutralized. The resins thus obtained are used in papermaking as assistants for increasing the dry and wet strength of paper and result in less dulling of the whiteness of the paper.

Abstract: Graft polymers are obtainable by free radical polymerization of(A) monomers or monomer mixtures of(a) from 10 to 100% by weight of open-chain N-vinylcarboxamides(b) from 0 to 90% by weight of other, carboxyl-free monoethylenically unsaturated monomers which are copolymerizable with the monomers (a) and(c) from 0 to 5% by weight of monomers containing two or more ethylenically unsaturated, non-conjugated double bonds in the molecule, in the presence of(B) natural substances containing saccharide structures, such as mono-, oligo- and polysaccharides,in a weight ratio (A):(B) of from 95:5 to 20:80 and, if required, subsequent hydrolysis of the amido groups of the polymerized monomers (a) of the graft polymer with formation of amino groups, and said polymers are used as dry and wet strength agents for paper, board and cardboard.

Abstract: Paper, board and cardboard are produced by draining a paper stock in the presence of a nonhydrolyzed copolymer which contains, as polymerized units,(a) from 99 to 1 mol % of N-vinylformamide and(b) from 1 to 99 mol % of one or more water-soluble basic monomers of the formula ##STR1## where R.sup.1 is H, CH.sub.3 or C.sub.2 H.sub.5, R.sup.2, R.sup.3 and R.sup.4 are each H, CH.sub.3, C.sub.2 H.sub.5 or (--CH.sub.2 --CH.sub.2 --O--).sub.n H, R.sup.5 and R.sup.6 are each C.sub.1 -C.sub.10 -alkyl, A is C.sub.1 -C.sub.6 -alkylene, n is from 1 to 6 and Y.sup..crclbar. is an anion, in an amount of from 0.01 to 3.5% by weight, based on dry paper stock.

Abstract: Bridged, water-soluble copolymers are obtainable by(A) copolymerization of a monomer mixture of(a) from 50 to 99 mol % of acrylamide and/or methacrylamide,(b) from 50 to 1 mol % of a monoethylenically unsaturated monomer containing actual groups and(c) from 0 to 20 mol % of monomers which differ from (a) and (b),in the presence of a polymerization initiator under conditions such that the acetal groups of the monomers (b) undergo virtually no hydrolysis,(B) hydrolysis of the acetal groups of the monomers (b), present as copolymerized units in the copolymers (A),(C) condensation of the copolymers (B) containing aldehyde groups at a pH above 5, at most to a degree such that the resulting condensates are still water-soluble and(D) stopping of the condensation reaction by adding acid until the pH reaches 3 or less,and are used as paper stock additives in papermaking for increasing the wet strength of paper.

Abstract: Paper, board, and cardboard having high dry strength are made by adding to the paper stock a dry strength agent which is obtainable by mixing enzymatically digested starch having a viscosity of from 20 to 2,000 mPa.s (measured in 7.5% strength aqueous solution at 45.degree. C.) and a cationic polymer which contains, as typical copolymerized monomers,(a) diallyldimethylammonium chloride,(b) N-vinylamine or(c) an unsubstituted or substituted N-vinylimidazoline, the K value of the cationic polymer in each case being not less than 30, and draining the paper stock with sheet formation.

Abstract: The novel compounds of the general formula ##STR1## where R.sup.1 and R.sup.2 are identical or different aliphatic, cycloaliphatic, aromatic or heterocyclic radicals which are free of groups which impart water solubility,X, Y and Z are each chlorine, bromine or a radical OR.sup.3 andR.sup.3 is unsubstituted or substituted phenyl, naphthyl or anthryl,are very useful as fluorescent dyes in organic material.

Abstract: Paper and paperboard of high dry strength are produced by adding a dry strength enhancer to the paper stock and dewatering the paper stock with sheet formation by using as the dry strength enhancer a mixture of a cationic polymer which contains as characteristic monomers copolymerized units of(a) diallyldimethylammonium chloride,(b) N-vinylamine or(c) a substituted or unsubstituted N-vinylimidazoline and has a K value of not less than 30, and natural potato starch which is converted into a water-soluble form by heating in an aqueous medium at above the gelatinization temperature of natural potato starch in the absence of any oxidizing agents or alkali.

Abstract: A process for the drying of inorganic hydrogels obtained from readily hydrolyzable compounds of the elements Al, Si, Ti, B, La, Zr, Cr, Sn, Th or Mg, and organic hydrogels based on gelatine, albumin or agar agar, from CO.sub.2, to give aerogels is easy to carry out industrially, and drying can be effected at from room temperature to 90.degree. C.The resulting aerogels are transparent and have a low bulk density and low thermal conductivity.The aerogels can be used as packing materials for liquid chromatography, as catalyst carriers, as substrates for enzymes and as adsorbents.