摘要:
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.
摘要:
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.4 -alkylene oxide) unit, andR.sup.7 is a carbamoyl radical ##STR5## or a biuret group R.sup.Ib ##STR6## in which one R.sup.8 is hydrogen and the other is as defined for R.sup.7 or a biuret group R.sup.Ic ##STR7## in which one R.sup.9 is as defined for R.sup.7 and the other is as defined for R.sup.1or a thioallophanate group R.sup.Id ##STR8##
摘要:
High-functionality polyisocyanates are prepared by a process which comprises (i) preparation of an addition product (A) which contains one group which is reactive toward isocyanate and at least two isocyanate groups by reacting (a) a diisocyanate or polyisocyanate I with (b1) compounds having at least three groups which are reactive toward isocyanate or (b2) compounds containing two groups which are reactive toward isocyanate or mixtures of (b1) and (b2), where at least one of the components (a) or (b) has functional groups having differing reactivities toward the functional groups of the other component and the reaction ratio is selected so that the addition product (A) contains an average of one group which is reactive toward isocyanate, (ii) if desired, intermolecular addition reaction of the addition product (A) to form a polyaddition product (P) containing an average of one group which is reactive toward isocyanate and an average of more than two isocyanate groups, and (iii) reaction of the addition product (A) and/or the polyaddition product (P) with a diisocyanate or polyisocyanate II.
摘要:
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.
摘要:
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.
摘要:
Polyisocyanates are prepared by a process which comprises (i) preparation of an addition product (A) which contains one group which is reactive toward isocyanate and one isocyanate group by reacting (a) a diisocyanate I with (b) compounds containing two groups which are reactive toward isocyanate, where at least one of the components (a) or (b) has functional groups having differing reactivities toward the functional groups of the other component, (ii) if desired, intermolecular addition reaction of the addition product (A) to form a polyaddition product (P) which contains one group which is reactive toward isocyanate and one isocyanate group and (iii) reaction of the addition product (A) and/or the polyaddition product (P) with a diisocyanate or polyisocyanate II which is different from diisocyanate I.
摘要:
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.
摘要:
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.
摘要:
Sheet-like polyurethane moldings are produced by impregnation of porous sheets with a prepolymer containing free isocyanate groups and reversibly blocked isocyanate-reactive groups or containing free isocyanate-reactive groups and reversibly blocked isocyanate groups, and subsequent reaction of the prepolymers in a heated mold.
摘要:
A process for the preparation of polyisocyanates which contain one or more biuret groups, by reacting a) an aliphatic or cycloaliphatic isocyanate containing two or more isocyanate groups (isocyanate a) with b) a tertiary alcohol or a mixture of water and a tertiary alcohol (biuretizing agent b) at from 100 to 250° C., which comprises carrying out the reaction in the presence c) of a stabilizer (c) which constitutes a catalytic amount of urea, ammonia, biuret, a urea derivative of the formula I in which R1, R2, R3 and R4 are hydrogen, C1 to C10 alkyl or C5 to C10 aryl, or a carboxamide of the formula II in which R5 is C1 to C12 alkyl which is unsubstituted or in which 1, 2 or 3 hydrogen atoms are replaced by a radical