摘要:
In magnetic recording media consisting of a nonmagnetic substrate and one or more magnetizable layers bonded thereon and based on a polyurethane binder, the binder consists of not less than 50% by weight of an isocyanate-free, branched polyurethane which is soluble in tetrahydrofuran and has sulfonate groups along the polyurethane branches and OH-containing urea groups at the chain ends and a molecular weight of from 4,000 to 30,000.
摘要:
The use of free, aromatic acids which contain at least two aromatic ring systems or at least two acid functions, and/or salts thereof, for influencing rock formations in the exploitation of underground mineral oil and/or natural gas deposits is described. The free acids are used in particular for influencing and especially controlling the flow of acid into rock formations in so-called acidizing methods. Suitable salts of said aromatic acids serve for reducing the rock permeability and in particular reducing the inflow of water into the well bore. In addition to this use, corresponding methods are also claimed.
摘要:
In magnetic recording media consisting of a nonmagnetic substrate and at least one magnetizable layer firmly applied thereon and based on magnetic material dispersed in a binder mixture which contains at least one hydroxyl-containing, preferably low molecular weight polyureaurethane and one polyurethaneurea (meth)acrylate, the polyurethaneurea (meth)acrylate is obtained by reacting a poly(meth)acrylate having up to 2 terminal OH groups per mol and a molecular weight of from 200 to 50,000 with a mixture of aliphatic polyisocyanates having an average functionality of from 3.0 to 6.0 NCO groups per mol, consisting offrom 0.1 to 10% by weight of a diisocyanate, from 30 to 80% by weight of a triisocyanate and from 20 to 60% by weight of an isocyanate having a functionality of from 4 to 10, with the proviso that from 1.2 to 3.0 NCO groups react per OH group and the remaining NCO groups are converted into substituted terminal urea groups with a polyfunctional amine or with a mixture of different polyfunctional amines.
摘要:
Described is a process for preparing 1-(2-sulfoethyl)pyridinium betaine wherein pyridine is reacted with a sulfoethylating agent from the group consisting of carbyl sulfate, ethionic acid and its salt and vinylsulfonic acid and vinylsulfonate, the reaction taking place in aqueous solution or in pyridine.
摘要:
A polymeric material I is obtainable by reacting 1) a polymer II of a) from 80 to almost 100 mol % of a C.sub.1 -C.sub.25 -alkyl ester of an .alpha.,.beta.-unsaturated carboxylic acid, b) from 0 to 20 mol % of one or more further monomers and c) an initiator and/or regulator by means of which the majority of the polymer chains of the polymer II are terminated at one of their ends by a hydroxyl group, 2) with a polyfunctional nonaromatic isocyanate III to give a reaction product IV, the amount of isocyanate groups being from 1.2 to 3.9 mol per mole of the hydroxyl groups in II, 3) reacting IV with a) a compound V, containing groups reactive toward isocyanates, to give a reaction product VI, the amount of reactive groups being from 2 to 7 mol per mole of the free isocyanate groups still present in IV, and reacting VI with a compound VII to give the polymer I, which reacts with the reactive groups which are still free in VI and by means of which acidic groups are introduced into VI, or b) a compound VIII which contains groups reactive toward isocyanates and by means of which the acidic groups are introduced into IV, to give the polymer I. The polymeric materials can be used as dispersing resin for pigment-containing coatings, in particular for the production of magnetic recording materials.
摘要:
Magnetic recording media consist of a nonmagnetic substrate and at least one magnetizable layer which is firmly applied thereon is based on a magnetic material dispersed in at least one polyureaurethane and a polyurethaneurea (meth)acrylate, the polyurethaneurea (meth)acrylate being obtained by reacting a polyacrylate with a mixture of di- and polyisocyanates and converting the remaining NCO groups into substituted urea groups with aminoalkyltrialkoxysilanes.
摘要:
Magnetic recording media consist of a nonmagnetic substrate and one or more magnetizable layers bonded thereon and based on a polyurethane binder, the binder consisting of not less than 50% by weight of a branched polyurethane elastomer having sulfonate groups and possessing urea groups at the chain ends.