| 摘要 |
A dispersing agent or protective colloid comprises a water-soluble copolymer of carboxylic acid amides or a water-soluble copolymer of at least 15 per cent by weight of an unsaturated carboxylic acid amide or of mixtures of unsaturated carboxylic acid amide or of mixtures of unsaturated carboxylic acid amides, with reference to the total amount of monomers, with one or more other monomers and having its k-value increased by heating its aqueous or water-containing solution to a temperature above 50 DEG C. The heat treatment to increase the k-value is preferably used on 5 to 40 per cent solutions; 1 to 70 per cent solutions may also be used and the temperature should generally lie between 100 DEG and 140 DEG C. Aqueous solvents in which the process may be carried out include methanol, propanol, butanol, glycol, propane-diol, glycerine, acetone, methyl ethyl ketone, dimethyl formamide, acetonitrile, tetrahydrofurane or dioxane and the solvent need not be complete miscible with water. The dispersing agent may be used for oils, waxes, fats, hydrocarbons, sulphur, linseed oil used in paints (Example 15), titanium/iron oxide pigments (Example 14), phthalocyanine due pigments and paraffin. The dispersing media include methanol, propanol, butanol, cyclohexanol, glycol, propane-diol, butane-diol, glycerine, butane-triol, acetone, methyl ethyl ketone, cyclohexanone, aliphatic and aromatic hydrocarbons with nitrogen and halo derivatives, dimethyl formamide, nitriles, ethers and cyclic ethers. Specification 757,770 is referred to.ALSO:A dispersing agent or protective colloid comprises a water-soluble copolymer of carboxylic acid amides or a water-soluble copolymer of at least 15 per cent by weight of an unsaturated carboxylic acid amide or of mixtures of unsaturated carboxylic acid amides, with reference to the total amount of monomers, with one or more other monomers and having its k-valve increased by heating its aqueous or water-containing solution to a temperature above 50 DEG C. The heat treatment to increase the k-value is preferably used on 5 to 40 per cent solutions 1 to 70 per cent solutions may also be used and the temperature should generally lie between 100 DEG and 140 DEG C. Aqueous solvents in which the process may be carried out include methanol, propanol, butanol, glycol, propane-diol, glycerine, acetone, methyl ethyl ketone, dimethyl formamide, acetonitrile, tetrahydrofurane or dioxane and it need not be completely miscible with water. Unsaturated carboxylic acid amides which can be used include acrylamide, methacrylamide, alpha and beta substituted alkyl halo acrylamides such as ethyl acrylamide, crotonamide, alpha-chloracrylamide, acrylamides with substituents on the nitrogen atoms such as N-methylacrylamide and N-ethylacrylamide, unsaturated dicarboxylic acid diamides such as fumaric acid diamide. Monomers which may be used for polymerization with amides comprise vinyl lactams such as N-vinyl pyrrolidone and N-vinyl caprolactam, acrylic acid, methacrylic acid, vinyl ethers, vinyl methyl ether and vinyl propyl ether, maleic acid, fumaric acid and their salts, e.g. as described in Specification 757,770, nitriles such as acrylonitrile and methacrylonitrile, vinyl ethers, vinyl esters such as vinyl acetate and propionate, acrylic acid esters such as acrylic acid methyl and ethyl esters, carboxylic acid amides which are substituted on nitrogen such as N,N-diethylacrylamide, acrylic urea and vinyl halides. Particularly mentioned are polymers of methacrylamide with N-vinyl pyrrolidone, methacrylamide with vinyl chloride, methacrylamide with acrylamide, methacrylamide with acrylamide and maleic acid, methacrylamide with N-vinyl pyrrolidone and fumaric acid diamide, acrylamide with methacrylamide and N-vinyl pyrrolidone, methacrylamide with N-diethyl acrylamide and N-vinyl pyrrolidone. The dispersing agent may be used for dicarboxylic acid condensation products with polyhydric alcohols, phenol resins, modified resins, cumarone resins, polyamides, polyurethanes, urea-formaldehyde resins and polyesters as well as melamine-formaldehyde condensates. The dispersing media include methanol, propanol, butanol, cyclohexanol, glycol, propanediol, butane-diol, glycerine, butane-triol, acetone, methyl ethyl ketone, cyclohexanone, aliphatic and aromatic hydrocarbons with nitrogen and halo derivatives, dimethyl formamide, nitriles ethers and cyclic ethers. They are suitable for foaming glues on the basis of urea-formaldehyde condensates. A list of polymerization reactions which are aided by the new dispersing agents is also given, e.g. the copolymerization in an aqueous medium of acrylonitrile and butylacrylate. 495 parts of 85 per cent colloidal sulphur with a particle size of about 5 microns, 175 parts of a 20 per cent solution of a copolymer derived from 70 per cent of methacrylamide and 30 per cent of N-vinyl pyrrolidone which has been heated for 40 hours at 95 DEG C. and 30 parts of water are stirred violently for half an hour at room temperature or kneaded for 2 hours. A thick pasty dispersion is obtained which is suitable for the vulcanization of rubber. |
