Method for producing a two-layer coating and suitable enamel therefor
AssigneeBASF Coatings GmbH
InventorsUlrich Poth, Bärbel Wiatr
Life of this patent
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Abstract
The present invention relates to coating materials with hydroxyl-containing polymers and di- and/or polyisocyanates, at least some of whose isocyanate groups are blocked with a mixture of from 30 to 85% by weight of one or more dialkyl malonates in which at least one of the ester radicals is an aliphatic, cycloaliphatic and/or araliphatic secondary alkyl radical having at least 3 carbon atoms and 70 to 15% by weight of at least one other dialkyl malonate. Preparation and the blocked polyisocyanates and coating materials and use of the coating materials is also provided.
Claims16
A coating material comprising:
- A) at least one hydroxyl-containing polymer, and
- B) at least one blocked diisocyanate and/or polyisocyanate wherein some of the isocyanate groups are blocked with dialkyl malonate,
- wherein the isocyanate groups of component (B) are blocked with a mixture of dialkyl malonates comprising:
- b1) from about 30 to about 85% by weight of at least one dialkyl malonate of the general formula (I)
- and/or at least one dialkyl malonate of the general formula (II)
- where
- R1, R2, and R3 are each independently selected from aliphatic, cycloaliphatic, or araliphatic secondary alkyl radicals having at least 3 carbon atoms, and
- R4 is an aliphatic, cycloaliphatic, aromatic or araliphatic hydrocarbon radical,
- and
- b2) from about 70 to about 15% by weight of at least one dialkyl malonate other than component (b1),
- the sum of components (b1) and (b2) being in each case 100% by weight.
A process for preparing diisocyanates and/or polyisocyanates blocked with dialkyl malonates, comprising the steps of:
- (a) reacting at least some of the isocyanate groups of the diisocyanate and/or polyisocyanate with a member of the group consisting of dimethyl malonate, diethyl malonate, and mixtures thereof;
- (b) transesterifying the reaction product obtained with at least one secondary alcohol having at least 3 carbon atoms selected from a group consisting of aliphatic, cycloaliphatic, and aromatic alcohols and mixtures thereof.
Dependencies are inferred from the claim text.