Abstract: The invention provides a composition for producing surface coatings combining improved hardness, scratch resistance and acid resistance with good reflow behavior, a process for preparing such a surface coating, and for the use of polyisocyanatoisocyanurates having a functionality of more than 3.5 and a viscosity at 23° C. of more than 3500 to produce surface coatings.

Abstract: A polyisocyanate of formula (I) OCN—R1—[—NX—CO—O—R2—O—CO—NH—R1—]n—NCO in which the units R1, X and R2 have the meanings: R1 is a unit of the formula (II): —CH2—CH2—CH2—CH2—CH2—CH2—  (II) X is hydrogen or a unit of the formula (III): —CO—NH—R1—NCO  (III), with the proviso that at least one of the units X in the polyisocyanates is a unit of formula (III); and R2 • is a 4-, 5- or 6-membered cycloalkylene group containing radical.

Abstract: Mixtures comprise a) polyisocyanates (polyisocyanates A), comprising structural units selected from the isocyanurate and biuret group, derived from aliphatic or cycloaliphatic diisocyanates (diisocyanates C), b) non-A polyisocyanates (polyisocyanates B), comprising structural units selected from the allophanate and urethane group, derived from b1) aliphatic or cycloaliphatic diisocyanates (diisocyanates C) and b2) polyhydric aliphatic or cycloaliphatic alcohols (alcohols A), the molar ratio of the polyisocyanates A to the polyisocyanates B being from 200:1 to 5:1.

Abstract: A process for preparing biuret-functional polyisocyanates from at least one aliphatic or cycloaliphatic diisocyanate and from at least one amine or water or a mixture thereof as reactants involves mixing the reactants with one another in a mixing unit having a high shear action.

Abstract: Diisocyanates of the formula (I) where R1 is a C1-C10-hydrocarbon radical and R3 is a C1-Cl2-hydrocarbon group and n is an integer from 1 to 10, are described.

Abstract: Two-component polyurethane systems composed of an at least bifunctional polyisocyanate component and a polyol component have a polyol component which comprises at least one hydroxyl-containing cyclic acetal and/or ketal.

Abstract: A process for the preparation of isocyanurate and urethane group-containing and, if desired, uretdiode and allophanate group-containing polyisocyanate mixtures by partially cyclizing organic, preferably (cyclo)aliphatic diisocyanates, in the presence of trimerization catalysts, deactivating these catalysts, reacting the partially trimerized, isocyanurate and, if desired, uretdiode group-containing polyisocyanate mixture with 0.5 to 10 mol % of at least one aliphatic or cycloaliphatic alcohol and/or polyoxyalkylene alcohol, and separating off the monomeric diisocyanates.

Abstract: Binders contain(A) copolymers of(a) from 5 to 70% by weight of monoesters of acrylic acid and/or methacrylic with dihydric to hexahydric C.sub.2 -C.sub.18 -alcohols,(b) from 0.1 to 80% by weight of esters or amides of acrylic acid and/or methacrylic acid with monofunctional C.sub.2 -C.sub.20 -alcohols or -amines which have an open-chain and/or cyclic urea group in the ester or amide radical,(c) from 1 to 60% by weight of esters of acrylic acid and/or methacrylic acid with monofunctional C.sub.1 -C.sub.20 -alcohols and(d) from 0 to 60% by weight of other comonomers, and(B) polyisocyanates, some or all of whose isocyanate groups may be blocked with CH--, NH--- or OH--acidic blocking agents and which have an isocyanate functionality of from 2.5 to 6.These binders are employed for the preparation of polyurethane finishes, which are used to produce coatings.