Coating compositions and coatings produced therefrom with improved soiling resistance and (self-)cleaning properties and use thereof

Patent metadata

Field	Value
Publication number	US-11597794-B2
Application number	US-201716303857-A
Country	US
Kind code	B2
Filing date	May 18, 2017
Priority date	May 24, 2016
Publication date	Mar 7, 2023
Grant date	Mar 7, 2023

Abstract

Coating compositions and coatings with improved soiling resistance and (self-)cleaning properties are disclosed. The coating compositions and coatings may be nonaqueous coating compositions and may include at least one hydroxyl group-containing compound, at least one isocyanate group-containing compound having free or blocked isocyanate and silane groups, at least one catalyst for the crosslinking of the silane groups, and at least one alkoxysilyl-functional siloxane.

First claim

The invention claimed is:

1. A nonaqueous coating composition comprising:
(A) at least one hydroxyl group-containing compound (A) having a hydroxyl number of 100 to 400 mg KOH/g and a Tg>−35° C., which is present at not less than 25 wt %, based on the binder fraction of the coating composition,
(B) at least one isocyanate group-containing compound (B) having free or blocked isocyanate groups, compound (B) comprising at least one structural unit of the formula (I)
—NR—(X—SiR″ x (OR′) 3-x )  (I),

and/or at least one structural unit of the formula (II),
—N(X—SiR″ x (OR′) 3-x ) n (X′—SiR″ y (OR′) 3-y ) m   (II),

where
R=hydrogen, alkyl, cycloalkyl, aryl, or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur, or NRa groups, with Ra=alkyl, cycloalkyl, aryl, or aralkyl,
R′=hydrogen, alkyl, or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur, or NRa groups,
X, X′=linear and/or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms,
R”=alkyl, cycloalkyl, aryl, or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur, or NRa groups,
n=0 to 2, m=0 to 2, m+n=2, and x, y=0 to 2,
and
(C) at least one catalyst (C) for the crosslinking of silane groups,
wherein additionally there is
(D) at least one alkoxysilyl-functional siloxane of the formula (III)
R 1 —SiR 2 2 -A x -B y —O—SiR 3 2 —R 4   (III)

in which
A is a group —[O—SiR 5 2 ]— and B is a group —[O—SiR 6 R 7 ]—,
R 2 , R 3 , R 5 , and R 6 independently of one another are linear or branched alkyl groups having 1 to 4 carbon atoms,
R 1 , R 4 , and R 7 independently of one another are a group -L-R 8 ,
in which L=a linear or branched divalent alkyl group and
R 8 =H or —Si(R 9 ) z (OR 10 ) 3-z with R 9 , R 10 =a linear or branched alkyl group having 1-4 carbon atoms and z=0, 1, or 2,
with the proviso that at least one of the radicals R 1 or R 4 and/or at least one group B constitutes a group R 8 =—Si(R 9 ) z (OR 10 ) 3-z ,
x independently is an integer of 1-20,
y independently is an integer of 0-10.

2. The coating composition as claimed in claim 1 , which is a two-component coating composition, wherein the alkoxysilyl-functional siloxane (D) and compound (A) are comprised in the same component.

3. The coating composition as claimed in claim 1 , wherein R 2 , R 3 , and R 5 independently of one another are a methyl and/or ethyl,
R 1 and R 4 independently of one another are a group -L-R 8 , in which L=a linear or branched divalent alkyl group, and R 8 =—Si(R 9 ) z (OR 10 ) 3-z with R 9 , R 10 =a linear or branched alkyl group having 1-4 carbon atoms and z=0, 1, or 2,
and y=0.

4. The coating composition as claimed in claim 3 , wherein the divalent alkyl group is ethylene.

5. The coating composition as claimed in claim 1 , containing no fluorine-containing compounds which lead to hydrophobation of the coating resulting therefrom.

6. The coating composition as claimed in claim 1 , comprising as polyhydroxyl group-containing compound (A) at least one poly(meth)acrylate resin having an OH number of 100 to 300 mg KOH/g, and a glass transition temperature of −35 to 100° C., (measured by means of DSC measurements in accordance with DIN EN ISO 11357-2).

7. The coating composition as claimed in claim 6 , wherein the at least one poly(meth)acrylate resin has an OH number of 150 to 200 mg KOH/g.

8. The coating composition as claimed in claim 1 , comprising at least one phosphorus- and nitrogen-containing catalyst (C).

9. The coating composition as claimed in claim 1 , wherein the compound (B) has been prepared by reacting polyisocyanates and/or their isocyanurate trimers and/or their allophanate dimers and/or their biuret dimers and/or uretdione dimers with at least one compound of the formula (Ia)
H—NR—(X—SiR″ x (OR′) 3-x )  (Ia)

and/or at least one compound of the formula (IIa),
HN(X—SiR″(OR′) 3-x ) n (X′—SiR″ y (OR′) 3-y ) m   (IIa),

where the substituents have the definition stated in claim 1 .

10. A method for producing coatings by applying to an optionally precoated substrate the coating composition as claimed in claim 1 .

11. The method as claimed in claim 10 , which is used for producing a coating for automotive OEM finishing, the finishing of parts for installation in or on automobiles, and/or the finishing of commercial vehicles, and or automotive refinishing.

12. A coating produced by a method as claimed in claim 10 .

13. The coating as claimed in claim 12 , which possesses a glass transition temperature (Tg)>70° C. and a crosslinking density>3.0×10 7 Pa.

14. A method for producing coatings, wherein a pigmented basecoat material and thereafter the coating composition as claimed in claim 1 are applied to an optionally pretreated and optionally precoated substrate.

15. The method as claimed in claim 14 , wherein following application of the pigmented basecoat, the applied basecoat material is first dried at temperatures of 20 to 80° C. and, following application of a nonaqueous coating composition comprising:
(A) at least one hydroxyl group-containing compound (A) having a hydroxyl number of 100 to 400 mg KOH/g and a Tg>−35° C., which is present at not less than 25 wt %, based on the binder fraction of the coating composition,
(B) at least one isocyanate group-containing compound (B) having free or blocked isocyanate groups, compound (B) comprising at least one structural unit of the formula (I)
—NR—(X—SiR″ x (OR′) 3-x )  (I),

and/or at least one structural unit of the formula (II),
—N(X—SiR″ x (OR′) 3-x ) n (X′—SiR″ y (OR′) 3-y ) m   (II),

where
R=hydrogen, alkyl, cycloalkyl, aryl, or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur, or NRa groups, with Ra=alkyl, cycloalkyl, aryl, or aralkyl,
R′=hydrogen, alkyl, or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur, or NRa groups,
X, X′=linear and/or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms,
R″=alkyl, cycloalkyl, aryl, or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur, or NRa groups,
n=0 to 2, m=0 to 2, m+n=2, and x, y=0 to 2,
and
(C) at least one catalyst (C) for the crosslinking of silane groups,
wherein additionally there is
(D) at least one alkoxysilyl-functional siloxane of the formula (III)
R 1 —SiR 2 2 -A x -B y —O—SiR 3 2 —R 4   (III)

in which
A is a group —[O—SiR 5 2 ]—and B is a group —[O—SiR 6 R 7 ]—,
R 2 , R 3 , R 5 , and R 6 independently of one another are linear or branched alkyl groups having 1 to 4 carbon atoms,
R 1 , R 4 , and R 7 independently of one another are a group -L-R 8 ,
in which L=a linear or branched divalent alkyl group and
R 8 =H or —Si(R 9 ) z (OR 10 ) 3-z with R 9 , R 10 =a linear or branched alkyl group having 1-4 carbon atoms and z=0, 1, or 2,
with the proviso that at least one of the radicals R 1 or R 4 and/or at least one group B constitutes a group R 8 =—Si(R 9 ) z (OR 10 ) 3-z ,
x independently is an integer of 1-20,
y independently is an integer of 0-10,
is cured at temperatures of 20 to 200° C. during a time of one minute up to 10 hours.

16. A method of improving the soiling resistance and the (self-)cleaning properties of coatings by applying the coating composition as claimed in claim 1 .

17. The coating as claimed in claim 12 , which possesses a soiling resistance of ΔL* 1-2 <30, where Δ

Assignees

• Basf Coatings Gmbh

Inventors

• Weiher Christian
• Austrup Berthold
• Janssen Andreas

Classifications

• C08G18/809

  containing silicon · CPC title

• C08G18/73

  acyclic · CPC title

• C08G18/672 Primary

  Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen · CPC title

• C08G18/755

  and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate · CPC title

• C08G18/778

  silicon · CPC title