Coating agents having high scratch resistance and weathering stability
Disclosed are coating compositions comprising at least one hydroxyl-containing compound (A) and at least one isocyanato-containing compound (B), wherein one or more of the constituents of the coating composition comprise between 2.5 and 97.5 mol %, based on the entirety of structural units (I) and (II), of at least one structural unit of the formula (I) —N(X—SiR″ x (OR′) 3-x ) n (X′—SiR″ y (OR′) 3-y ) m (I) and between 2.5 and 97.5 mol %, based on the entirety of structural units (I) and (II), of at least one structural unit of the formula (II) —Z—(X—SiR″ x (OR′) 3-x ) (II).
1. A coating composition having an aprotic solvent with a water content of not more than 1% by weight based on the aprotic solvent, comprising:
at least one hydroxyl-containing compound (A); and
at least one isocyanato-containing compound (B);
wherein one or more constituents of the coating composition comprise between 2.5 and 97.5 mol %, based on the entirety of structural units (I) and (II), of at least one structural unit of the formula (I)
—N(X—SiR″ x (OR′) 3-x ) n (X′—SiR″ y (OR′) 3-y ) m (I)
wherein
R′ =hydrogen, alkyl or cycloalkyl, wherein a carbon chain of the alkyl or cycloalkyl optionally comprises nonadjacent oxygen, sulfur or NRa groups, where Ra =alkyl, cycloalkyl, aryl or aralkyl,
X, X′ =linear and/or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms,
R″ =alkyl, cycloalkyl, aryl or araalkyl, wherein a carbon chain of the alkyl, cycloalkyl, aryl or aralkyl optionally comprises nonadjacent oxygen, sulfur or NRa groups, where Ra =alkyl, cycloalkyl, aryl or aralkyl,
n =0 to 2,
m =0 to 2,
m+n =2,
x =0 to 2, and
y =0 to 2,
and between 2.5 and 97.5 mol %, based on the entirety of structural units (I) and (II), of at least one structural unit of the formula (II)
—Z—(X—SiR″ x (OR′) 3-x ) (II),
wherein
Z =—NH—, —NR—, or —O—, with
R =hydrogen, alkyl, cycloalkyl, aryl or aralkyl, wherein a carbon chain of the alkyl, cycloalkyl, aryl or aralkyl is optionally interrupted by, sulfur or NRa groups, with Ra =alkyl, cycloalkyl, aryl or aralkyl,
R′ =hydrogen, alkyl or cycloalkyl, wherein a carbon chain of the alkyl or cycloalkyl is optionally interrupted by nonadjacent oxygen nonadjacent oxygen, sulfur or NRa groups, with Ra =alkyl, cycloalkyl, aryl or aralkyl,
X =linear and/or branched alkylene or cycloalkylene group having 1 to 20 carbon atoms,
R″ =alkyl, cycloalkyl, aryl or aralkyl, wherein a carbon chain of the alkyl, cycloalkyl, aryl or aralkyl is optionally interrupted by nonadjacent oxygen, sulfur or NRa groups, with Ra =alkyl, cycloalkyl, aryl or aralkyl,
x =0 to 2,
wherein the at least one isocyanato-containing compound (B) comprises the structural, units (I) and (II), and wherein the at least one hydroxyl-containing compound (A) comprises at least one poly(meth)acrylate polyol.
2. The coating composition of claim 1 , wherein one or more constituents of the coating composition comprise between 10 and 90 mol %, based on the entirety of the structural units (I) and (II), of at least one structural unit of the formula (I), and between 10 and 90 mol %, based on the entirety of the structural units (I) and (II), of at least one structural unit of the formula (II).
3. The coating composition of claim 1 , wherein, in the at least one isocyanato-containing compound (B), the at least one isocyanato-containing compound comprises a core polyisocyanate structure and between 2.5 and 90 mol % of isocyanate groups in the core polyisocyanate structure have undergone reaction to structural units (I) and between 2.5 and 90 mol % of isocyanate groups in the core polyisocyanate structure have undergone reaction to structural units (II) and the total fraction of isocyanate groups in the core polyisocyanate structure that have undergone reaction to structural units (I) and (II) is between 5 and 95 mol %.
4. The coating composition of claim 1 , further comprising from 0.1% to 20% by weight, based on nonvolatile constituents of the coating composition, of an amine-blocked phosphoric acid.
5. The coating composition of claim 1 that is a clearcoat material for automotive OEM finishing or automotive refinish.
6. The coating composition of claim 1 , wherein one or more constituents of the coating composition comprise between 20 and 80 mol %, based on the entirety of the structural units (I) and (II), of at least one structural unit of the formula (I), and between 20and 80 mol %, based on the entirety of the structural units (I) and (II), of at least one structural unit of the formula (II).
7. The coating composition of claim 1 , wherein one or more constituents of the coating composition comprise between 30 and 70 mol %, based on the entirety of the structural units (I) and (II), of at least one structural unit of the formula (I), and between 30 and 70 mol %, based on the entirety of the structural units (I) and (II), of at least one structural unit of the formula (II).
8. The coating composition of claim 1 , wherein the at least one isocyanato-containing compound (B) comprises a core polyisocyanate structure and the core polyisocyanate structure is selected from the group consisting of isocyanurate trimers of 1,6-hexamethylene diisocyanate, isophorone diisocyanate, and 4,4′-methylenedicyclohexyl diisocyanate, the biuret dimers of the aforementioned polyisocyanates and/or the isocyanurate trimers of the aforementioned polyisocyanates.