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: Polyisocyanates of the formula (I) (polyisocyanate I),

Abstract: Mixtures comprise

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: Isocyanato compounds with capped, isocyanate-reactive groups are those of the formula I ##STR1## where R.sup.1 and R.sup.2 are hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.10 -aryl or C.sub.7 -C.sub.10 -aralkyl or together form C.sub.3 -C.sub.10 -alkanediyl,X and Y are --O--, --S-- or ##STR2## where R.sup.4 is hydrogen, C.sub.1 -C.sub.20 -alkyl which is uninterrupted or interrupted by oxygen atoms in ether function, or is C.sub.6 -C.sub.10 -aryl or C.sub.7 -C.sub.10 -aralkyl,R.sup.3 is C.sub.1 -C.sub.10 -alkanediyl which together with --X--CR.sup.1 R.sup.2 --Y-- forms a 4-7-membered ring,in which either one hydrogen in R.sup.3 or the radical R.sup.4 in ##STR3## is replaced by an allophanate group R.sup.Ia ##STR4## in which R.sup.5 is a divalent aliphatic, alicyclic, araliphatic or aromatic C.sub.2 -C.sub.20 hydrocarbon unit,R.sup.6 is a single bond or a divalent aliphatic, alicyclic, araliphatic or aromatic C.sub.1 -C.sub.20 hydrocarbon unit or a mono- or poly(C.sub.2 -C.sub.

Abstract: In one-component and two-component polyurethane coating compositions comprising at least one reactive component capable of reacting with polyisocyanates, the reactive component is a compound A) containing an isocyanate group, a urethane, thiourethane or urea group and two capped isocyanate-reactive groups.