摘要:
The invention relates to magnetic recording media comprising a non-magnetic base and, applied thereto, a firmly adhering magnetic coating based on a finely divided magnetic pigment dispersed in a binder which contains at least 50 percent by weight of a special polyurethane elastomer.This polyurethane elastomer is a thermoplastic polyurethane which is soluble in tetrahydrofuran and free from isocyanate groups, and which has been manufactured from (A) 1 mole of one or more hydroxyl-containing polyesters and/or hydroxyl-containing polyethers of molecular weight from 600 to 4,000, (B) from 3.5 to 15 moles of a branched-chain aliphatic diol of 4 to 10 carbon atoms or a mixture of aliphatic diols of 2 to 10 carbon atoms, of which at least 50 mole percent is a branched-chain aliphatic diol of 4 to 10 carbon atoms, (C) from 0 to 1 mole, but not more than 15 mole percent of the aliphatic diols according to B, of an aliphatic polyol with from 3 to 6 OH groups and 3 to 18 carbon atoms, and (D) from 4.5 to 18 moles of a diisocyanate of 6 to 30 carbon atoms, the amount of NCO groups being approximately equivalent to the amount of OH groups of the sum of the components A to C.Magnetic recording media which contain such a polyurethane in the magnetic coating are distinguished by high surface hardness coupled with a markedly improved orientation ratio, a higher packing density and more uniform dispersion of the magnetic particles in the coating.
摘要:
Magnetic recording media comprising a non-magnetic base and, applied thereto, a firmly adhering magnetic coating based on a finely divided magnetic pigment dispersed in a binder which contains at least 50 percent by weight of a special polyurethane elastomer, namely a thermoplastic polyurethane which is soluble in tetrahydrofuran, is free from isocyanate groups and has been manufactured from (A) 1 mole of a hydroxyl-containing polyester having a molecular weight of from 700 to 2,500, (B) from 0.3 to 3 moles of a linear aliphatic diol of 2 to 10 carbon atoms, (C) from 0.05 to 0.4 mole of a triol of 3 to 10 carbon atoms, and (D) from 1.35 to 4.7 moles of a diisocyanate of 6 to 30 carbon atoms, the amount of NCO groups being approximately equivalent to the amount of OH groups of the sum of components (A) to (C).
摘要:
Thermoplastic, elastic polyurethanes which are soluble in ethers and/or ketones and have a high surface hardness and high modulus of elasticity are manufactured from a polyester-ol and/or a polyether-ol, a substituted or unsubstituted diisocyanato-diphenylmethane or diisocyanato-diphenylsulfone, an aliphatic, branched-chain diol of the formula HOCH.sub.2 --CR.sup.1 R.sup.2 --CO.sub.2 OH, in which R.sup.1 is alkyl and R.sup.2 is alkyl or hydrogen, and, optionally, a triol.
摘要:
A process for the manufacture of magnetic recording media, comprising a non-magnetic base and, applied thereto, one or more magnetizable layers, consisting of an anisotropic magnetic material finely dispersed in an organic binder, wherein the binder contains at least 40% of an aqueous ionomeric polyurethane dispersion which at 50.degree. C. forms films having a modulus of elasticity of from 50 to 700 N/mm.sup.2 and a DIN No. 53,157 pendulum hardness of from 20 to 110 s, the corresponding values of the modulus and hardness at room temperature being more than 3.5 times higher.
摘要:
A process for the preparation of polymerizable, primarily linear thermoplastic polyurethane elastomers with acrylate side groups comprising reacting an organic polyisocyanate with a mixture of(a) an acrylate diol having a molecular weight of 146 to 3000,(b) an organic polyhydroxyl compound other than those of paragraph (a) having a molecular weight between 400 and 5000, and(c) a chain extender selected from the group consisting of diols, diamines, aminoalcohols, and triols, having molecular weights between 61 and 400, water, and mixtures thereofwherein the ratio of isocyanate to active hydrogen containing groups is from 0.8:1 to 1.2:1 and wherein 1.4 to 1.8 moles of organic polyisocyante, 0 to 15 moles of component (c) and 0.3 to 6 moles of component (a) are used per mole of component (b). The polymerizable polyurethane elastomers may be used for the manufacture of molded parts, laminates, adhesives, coatings, magnetic tapes, and other articles.
摘要:
Magnetic recording media comprise a non-magnetic base which is provided with a magnetic layer which consists of a dispersion of an anisotropic magnetic material in an organic binder which consists essentially of an OH-containing polyurea-urethane binder crosslinked with polyisocyanate. The OH-containing polyurea-urethane is obtained by reacting a polydiol, a diol and a primary or secondary aminoalcohol, and if appropriate a triol, with a diisocyanate.
摘要:
Magnetic recording media comprising a non-magnetic base and, applied thereto, one or more magnetizable layers based on an anisotropic magnetic material finely dispersed in an organic binder containing an ionomeric polyurethane elastomer, wherein the binder used is a substantially aqueous polyurethane dispersion prepared from a polyurethane solution which has been obtained by reacting a polyisocyanate with an organic polyhydroxy compound in the presence of an organic solvent that is inert to isocyanate groups.
摘要:
Magnetic recording media comprise a non-magnetic base and one or more magnetic layers consisting of an organic binder matrix containing finely divided magnetic material, the said matrix being obtained by electron beam curing of a mixture of from 50 to 100% by weight of a polyurethane acrylate polymer possessing polymerizable double bonds and from 0 to 50% by weight of an acrylate and/or an acrylate prepolymer and/or an N-vinyl monomer and/or an N-vinyl prepolymer.
摘要:
A process for coating electrically conductive objects comprisingA. immersing said object as the anode of an electric current in an aqueous polyurethane dispersion prepared by(1) forming a polyurethane solution by reacting an organic polyisocyanate in the presence of an organic solvent with(a) an acrylic ester diol having a molecular weight of between 146 and 3,000;(b) an organic polyhydroxyl compound other than (a) having a molecular weight between 400 and 5,000 selected from the group consisting of polyester, polyols, polyether polyols, polycarbonates, polylactones, and mixtures thereof; and(c) a chain extender selected from the group consisting of diols, triols, diamines, aminoalcohols, having a molecular weight between 62 and 400, water, and mixtures thereof;(2) forming an anionic polyurethane addition product by reacting said polyurethane solution with a mercaptocarboxylic acid salt in the presence of a solvent;(3) adding water; and(4) removing the organic solvent, andB. passing an electric current between the anode and a cathode which is also dispersed in said dispersion, andC. irradiating said object with ultraviolet radiation or electron rays.The process can be used for coating metals such as iron, steel and aluminum.
摘要:
A process for preparing aqueous polyurethane dispersions has been discovered which comprises(a) forming a polyurethane solution by reacting an organic polyisocyanate in the presence of a solvent with(i) an acrylic ester diol having a molecular weight of between 146 and 3,000;(ii) an organic polyhydroxyl compound other than (i) having a molecular weight between 400 and 5,000 selected from the group consisting of polyester polyols, polyether polyols, polycarbonates, polylactones, and mixtures thereof; and(iii) a chain extender having a molecular weight between 62 and 400 selected from the group consisting of diols, triols, diamines, aminoalcohols, and mixtures thereof;(b) forming an anionic polyurethane addition product by reacting said polyurethane solution with a mercaptocarboxylic acid salt in the presence of a solvent;(c) adding water; and(d) removing the solvent.The dispersions can be used in a variety of applications. For instance, they can be used to prepare films, coating, and binders.