摘要:
Multilayer magnetic recording medium is suitable for high recording densities and the recording of digital data, has very good electromagnetic recording properties in the entire recording wavelength range and good mechanical properties and possesses a flat frequency response and which has at least one upper magnetic recording layer less than 0.5 &mgr;m thick and at least one lower layer which contains a magnetically soft pigment.
摘要:
Multilayer magnetic recording medium which is suitable for high recording densities and the recording of digital data, has very good electromagnetic recording properties and good surface smoothness and can absorb a large amount of lubricant in the lower layer and has at least one upper magnetic recording layer less than 0.5 μm thick and at least one lower layer which contains a magnetically soft pigment.
摘要:
The thermoplastic, isocyanate-free polyurethane which contains acidic groups, is soluble in tetrahydrofuran, has a molecular weight of from 15,000 to 70,000 and is composed ofA) 1 mol of a polyol having a molecular weight of from 400 to 4000,B) from 0.3 to 9 mol of a mixture ofB1) if required, a diol of 2 to 18 carbon atoms andB2) from 0.03 to 0.4 mol of a diol having at least one acidic group,C) from 0 to 1 mol of a polyol having 3 to 18 carbon atoms and at least 3 OH groups,D) from 1.25 to 13 mol of a diisocyanate of 6 to 30 carbon atoms andE) from 0 to 1 mol of a primary or secondary amino alcohol of 2 to 16 carbon atoms,the molar ratio of the OH and any NH groups present in the sum of the components A, B, C and E to the NCO groups of component D being from 0.98 to 1.4, is obtainable by reacting the above components in the melt and is suitable in particular as a binder for magnetic recording media.
摘要:
Magnetic recording media consist of a nonmagnetic substrate and at least one magnetizable layer bonded thereon and based on a magnetic material dispersed in at least one polyurethane and one polyurethaneurea (meth)acrylate, the polyurethaneurea (meth)acrylate being obtained by reacting a hydroxyl-containing poly(meth)acrylate with a mixture of di- and polyisocyanates and converting the remaining NCO groups with ammonia or primary or secondary amines into urea groups.
摘要:
A polyurethane having at least one anionic anchor group L, the anchor group L being covalently bonded to a polyether segment having at least one nitrogen atom in the polyurethane.
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:
A binder composition, at least containing an inorganic filler and a thermoplastic block copolyurethane having in each case at least one soft segment (A) and at least one hard segment (B), at least one hard segment (B) containing a structural element of the formula I is used in particular for the production of magnetic recording media.
摘要:
Hydroxyl-containing polyurethanes I are composed essentially ofa) a diisocyanate of 6 to 30 carbon atoms (component II),b) a component III comprising.alpha.) an aliphatic diol of 2 to 20 carbon atoms or.beta.) an aromatic-aliphatic or aromatic-cycloaliphatic diol of 8 to 30 carbon atoms having nonphenolic hydroxyl groups as hydroxyl groups of the diol andc) a polyhydric alcohol having at least 3 hydroxyl groups, 3 to 18 carbon atoms and nonphenolic hydroxyl groups as hydroxyl groups of the alcohol (component IV),the amounts of components II to IV being such that the total number of nonphenolic hydroxyl groups is from 1.1 to 5.0 per isocyanate group of II.The polyurethanes can be used as binders or binder components for pigment-containing coatings, in particular for the production of magnetic recording materials.
摘要:
Magnetic recording media contain a nonmagnetic substrate and a magnetizable layer, the magnetizable layer containing ferromagnetic pigments and a system of polymeric materials, wherein the system of polymeric materials containsa) from 3 to 35% by weight of a polymer containing ionic or ionogenic groupsb) from 5 to 97% by weight of a polymer XIV which contains basic groups, and has a molecular weight of from 30000 to 2000000.
摘要:
Preparation of materials (I) having an average molecular weight from 4000 to 30,000, obtainable by reacting1) a polyurethane (II) comprisinga) 1 mol of a diol (III) having an average molecular weight of from 400 to 4000,b) from 0.3 to 9 mol of an aliphatic or cycloaliphatic diol (IV) of 2 to 18 carbon atoms,c) from 0.3 to 9 mol of an aromatic diol (V) of 8 to 30 carbon atoms,d) from 0.01 to 1 mol of a trihydric alcohol (VI) of 3 to 18 carbon atoms,e) from 0.001 to 1 mol of a polyhydric alcohol (VII) of 3 to 14 carbon atoms which contains a tertiary amino group andf) an amount of a diisocyanate (VIII) of 6 to 30 carbon atoms such that the molar ratio of the isocyanate groups to the total number of hydroxyl groups in (III) to (VII) is from 1.05:1 to 1.4:1with2) a compound (IX) which contains one or more hydroxyl groups and one or more amino groups reactive toward isocyanate groups, the amount of (IX) being such that the number of reactive amino groups corresponds to the number of isocyanate groups in the polyurethane (II).The materials may be used as crosslinkable binder components for pigment-containing coatings, in particular for the production of magnetic recording materials.