Abstract: Disclosed herein is an N-vinylformamide composition comprising 250 ppm by weight or less of formic acid based on N-vinylformamide.According to the invention, the purity and polymerizing activity of N-vinylformamide are preserved for a long time.

Abstract: There is provided a lactam ring-containing polymer comprising: 20 to 100 molar % of a structural unit represented by the general formula (1); 0 to 70 molar % of a structural unit represented by the general formula (2); and 0 to 70 molar % of a structural unit represented by the general formula (3) and/or a structural unit represented by the general formula (4): ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 each represents a hydrogen atom or a methyl group, and X represents COOR.sup.4 and/or CONR.sup.5 R.sup.6 in which R.sup.4, R.sup.5 and R.sup.6 each represents a hydrogen atom or a C1-C4 alkyl.The polymer is excellent in heat resistance and is expected to be used for resin modifiers, polymeric additives for petroleum tertiary recovery, and other various applications.

Abstract: An acrylic fiber has 99.9 to 85 mol % of acrylonitrile units, and 0.1 to 15 mol % of N-vinylcarboxylic acid amide units, wherein the latter unit may be modified. The fiber is excellent, e.g., in dyeing property and hygroscopicity, and can be readily converted into a functional fiber.

Abstract: Disclosed herein is a paper-making additive.comprising a specified cationic polymer having an amidine structure. The cationic polymer additive for paper-making according to the present invention has 20 to 90% by mole of units represented by the formula (1) and/or (2): ##STR1## wherein R.sup.1 and R.sup.2 independently denote a hydrogen atom or a methyl group, and X- denotes an anion; and has a reduced viscosity of 0.1 to 10 dl/g as measured in a 1N saline solution of 0.1 g/dl at 25.degree. C. The additives are excellent in improving paper or pulp properties, such as freeness, filler retention and paper strength.

Abstract: The present invention relates to a method for sizing of paper by using a particular vinylamine polymer as a size-fixing aid. By the use of the vinylamine polymer as a size-fixing aid, it has become possible to obtain a paper having superior sizing properties by papermaking at a pH around neutrality using a hitherto known acidic sizing agents without using a neutral sizing agent. The method of the present invention further has effects that operating efficiency of papermaking is greatly improved since contaminations of a papermaking machine due to a neutral agent can be avoided, and therefore, the prices of paper can be greatly lowered. The present method has further advantages when it is applied under acidic papermaking condition of a pH of less than 5.5. In such a condition, the addition amount of alum can be decreased and the life of a papermaking machine can be prolonged. In spite of a small amount of alum added, a considerably good sizing effect can be obtained by the present method.

Abstract: Disclosed herein is a flocculating agent comprising a specified cationic polymer having an amidine structure. The cationic polymer flocculating agents according to the present invention have 20 to 90% by mole of a repeating amidine unit represented by the formula (1) and/or (2): ##STR1## The agents have a reduced viscosity of 0.1 to 10 dl/g as measured in a 1N saline solution of 0.1 g/dl at 25.degree. C.The agents have a remarkably excellent performance as flocculating agents, in particular for organic sludge.

Abstract: Disclosed herein is a vinylamine copolymer having the structural units represented by the following formulas (I), (II), (III), (IV) and (V): ##STR1## wherein x.sup..crclbar. represents an anion or hydroxyl ion, R represents a hydrogen atom or a methyl group, M.sup..sym. represents a hydrogen ion or a monovalent cation, in which the molar fraction of the structural unit (I) is 5 to 85% by mole, the molar fraction of the structural unit (II) is 2 to 85% by mole, the molar fraction of the structural unit (III) is 5 to 80% by mole, the molar fraction of the structural unit (IV) is 0 to 40% by mole, all of said molar fractions being based on the vinylamine copolymer, and the molar fraction of the structural unit (V) is 0 to 8% by mole which is based on the total content of the structural units (III), (IV), and (V), a flocculating agent and a paper strength increasing agent using the vinylamine copolymer, and a process for producing the vinylamine copolymer.

Abstract: Disclosed herein are an N-vinylformamide copolymer having the structural units represented by the following formulas (I) and (II): ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group and R.sub.2 represents an alkyl group of 1 to 4 carbon atoms, in which the molar ratio between the structural units (I) and (II) is from 20:80 to 95:5, and a process for producing the N-vinylformamide copolymer.

Abstract: Disclosed herein is a vinylamine copolymer having the structural units represented by the following formulas (I), (II), (III), (IV) and (V): ##STR1## wherein X.sup..crclbar. represents an anion or hydroxyl ion, R represents a hydrogen atom or a methyl group, M.sup..sym. represents a hydrogen ion or a monovalent cation, in which the molar fraction of the structural unit (I) is 5 to 85% by mole, the molar fraction of the structural unit (II) is 2 to 85% by mole, the molar fraction of the structural unit (III) is 5 to 80% by mole, the molar fraction of the structural unit (IV) is 0 to 40% by mole, all of said molar fractions being based on the vinylamine copolymer and the molar fraction of the structural unit (V) is 0 to 8% by mole which is based on the total content of the structural units (III), (IV) and (V), a flocculating agent and a paper strength increasing agent using the vinylamine copolymer, and a process for producing the vinylamine copolymer.

Abstract: Disclosed herein is a process for preparing a water-soluble polymer, which comprises granulating a hydrous gel-like polymer obtained by polymerizing N-vinylformamide in the form of an aqueous solution of which a monomer concentration is 20 to 60% by weight, dispersing the formed polymer particles in methanol and contacting them with an aqueous solution of ammonium salt of a monovalent acid in an amount of 1 to 200% by mole based on the formamide groups in said polymer, thereby partially modifying the formamide groups in the polymer.

Abstract: Disclosed herein is a vinylamine copolymer having the structural units represented by the general formulae (I), (II) and (III): ##STR1## (wherein X represents an anion or hydroxyl ion) ##STR2## (wherein R.sup.1 represents hydrogen atom or a methyl group, R.sup.2 represents hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R.sup.3 represents an alkyl group having 1 to 4 carbon atoms or an oxoalkyl group having 4 to 8 carbon atoms) in which the molar fraction of the structural unit (I) is 5 to 85% by mole, the molar fraction of the structural unit (II) is 5 to 85% by mole, and the molar fraction of the structural unit (III) is 90 to 5% by mole, a flocculating agent, a drainage aid and a paper strength increasing agent using such vinylamine copolymer, and a process for producing such vinylamine copolymer.

Abstract: Disclosed herein are a coagulant for minute mineral particles in suspension, comprising a copolymer of 0.5 to 10 mol % of 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof, 40 to 99.5 mol % of N-hydroxymethylacrylamide and 0 to 59.5 mol % of acrylamide and showing a reduced viscosity of 10 to 30 dl/g in an aqueous 1N solution of sodium chloride at a temperature of 25.degree. C. and a concentration of the copolymer of 0.1 g/dl therein, and a method for coagulating the minute mineral particles in a suspension, comprising adding the coagulant a neutral waste water.

Abstract: Disclosed herein is a process for producing N-substituted formamide represented by the formula: ##STR1## wherein R represents a hydrogen atom or a residual radical of a primary or secondary alcohol, comprising the steps of reacting formamide with acetaldehyde in the presence of a basic catalyst and if required, further reacting the thus formed product, N-(.alpha.-hydroxyethyl)formamide, with a primary or secondary alcohol in the presence of an acid catalyst.

Abstract: Disclosed is a process for preparing a water-soluble bead polymer by dispersing drops of an aqueous solution of water-soluble vinyl monomer in a dispersing medium in the presence of a dispersion stabilizer, and polymerizing the monomer by using monomer selected from the following A and B(a) a compound of the general formula I ##STR1## wherein R.sup.1 is hydrogen or methyl, R.sup.2 and R.sup.3 may be the same or different and each is linear or branched alkyl of from 1 to 4 carbon atoms, R.sup.4 is hydrogen, linear or branched alkyl of from 1 to 8 carbon atoms, hydroxy alkyl of from 1 to 4 carbon atoms, or benzyl, Y is alkylene or hydroxyalkylene each of from 2 to 4 carbon atoms, and X.sup.- is an anion, or(B) a mixture of the compound of the formula I and a water-soluble vinyl monomer copolymerizable with the compound (I), and a cellulose ester or a cellulose ether insoluble in water but soluble in the dispersing medium is used as the dispersion stabilizer.

Abstract: An aqueous gel of a water-soluble polymer containing units of a quaternary ammonium salt of an alkylacrylate or a methacrylate is dehydrated by adding at least one salt of a divalent metal and a strong acid to said gel and then dehydrating said gel.

Abstract: .[.Disclosed herein is a vinylamine copolymer having the structural units represented by the following formulas (I), (II), (III), (IV) and (V): ##STR1## wherein X.sup..crclbar. represents an anion or hydroxyl ion, R represents a hydrogen atom or a methyl group, M.sup..sym. represents a hydrogen ion or a monovalent cation, in which the molar fraction of the structural unit (I) is 5 to 85% by mole, the molar fraction of the structural unit (II) is 2 to 85% by mole, the molar fraction of the structural unit (III) is 5 to 80% by mole, the molar fraction of the structural unit (IV) is 0 to 40% by mole, all of said molar fractions being based on the vinylamine copolymer and the molar fraction of the structural unit (V) is 0 to 8% by mole which is based on the total content of the structural units (III), (IV) and (V), a flocculating agent and a paper strength increasing agent using the vinylamine copolymer, and a process for producing the vinylamine copolymer..]..Iadd.

Abstract: Disclosed herein is a vinylamine copolymer having the structural units represented by the following formulas (I), (II), (III).[.,.]. .Iadd.and .Iaddend.(IV) .[.and (VI).].: ##STR1## wherein x.crclbar. represents an anion or hydroxyl ion R represents a hydrogen atom or a methyl group, M.sym. represents a hydrogen ion or a monovalent cation, in which the molar fraction of the structural unit (I) is 5 to 85% by mole, the molar fraction of the structural unit (II) is 2 to 85% by mole, the molar fraction of the structural unit (III) is 5 to 80% by mole,.[.the molar fraction of the structural unit (IV) is 0 to 40% by mole,.]. all of said molar fractions being based on the vinylamine copolymer, and the molar fraction of the structural unit .[.(V).]. (.Iadd.IV) is 0 to 8% by mole which is based on the total content of the structural units (III).[.,.]. .Iadd.and .Iaddend.(IV), .[.and (V),.].