Coating system having high surface roughness
A polyurea composition including a first component A with at least one isocyanate-functional polyurethane polymer P1 and a second component B including a blocked amine BA and optionally a polyamine PA having a molecular weight in the range from 60 to 500 g/mol. The polyurea composition further includes a silane S1 selected from the list consisting of isocyanatosilanes S1-1 and epoxy silanes S1-2 as well as an aminosilane S2 and an aggregate AG of an at 23° C. solid thermoset. The polyurea composition is notable for high surface roughness and for reliable and long-term bonding of the aggregates to the coating with no need for sealing. Further, the polyurea composition has enough adhesion to the substrate that the application of a primer layer on the substrate prior to application is not necessary.
1. A polyurea composition comprising:
a first component A comprising;
at least one isocyanate-functional polyurethane polymer P1;
a second component B comprising;
at least one blocked amine BA which has a blocked, hydrolytically activatable amino group and either at least one further blocked, hydrolytically activatable amino group or at least one reactive group R which is selected from the group consisting of hydroxyl group, mercapto group and secondary amino group;
wherein the polyurea composition further comprises:
at least one silane S1 selected from the list consisting of isocyanatosilanes S1-1 and epoxy silanes S1-2;
at least one aminosilane S2;
at least one aggregate AG of an at 23° C. solid thermoset;
wherein the weight ratio between S1/S2 is >2, and the total amount of the sum of (S1+S2) is 2-6 wt. % based on the total amount of the polyurea composition.
2. The polyurea composition as claimed in claim 1 , wherein the polyurethane polymer P1 is prepared from polyols that are a mixture of at least one diol chain extender and polyoxyalkylene polyols.
3. The polyurea composition as claimed in claim 1 , wherein the blocked, hydrolytically activatable amino group of the blocked amine BA is an aldimino group.
4. The polyurea composition as claimed in claim 1 , wherein the second component B further comprises at least one polyamine PA having a molecular weight in the range from 60 to 500 g/mol.
5. The polyurea composition as claimed in claim 1 , wherein the epoxy silane S1-2 is 3-glycidyloxypropyltrimethoxysilane.
6. The polyurea composition as claimed in claim 1 , wherein the isocyanatosilane S1-1 is 3-Isocyanatopropyltrimethoxysilane.
7. The polyurea composition as claimed in claim 1 , wherein the aminosilane S2 is 3-Aminopropyltrimethoxysilane.
8. The polyurea composition as claimed in claim 1 , wherein the weight ratio between S1/S2 is 2.05-3.5.
9. The polyurea composition as claimed in claim 1 , wherein the total amount of the sum of (S1+S2) is 2.75-4.5 wt. % based on the total amount of the polyurea composition.
10. The polyurea composition as claimed in claim 1 , wherein the at 23° C. solid thermoset is selected from the list consisting of polyallyl diglycol carbonate, styrene acrylonitrile, cross linked polyvinyl chloride, and cross linked urea formaldehyde.
11. The polyurea composition as claimed in claim 1 , wherein the polyurea composition contains less than 5 wt. % of at least one inorganic aggregate AZ.
12. A method for producing a coating with a polyurea composition as claimed in claim 1 , the method comprising the following method steps:
a) applying the polyurea composition to a substrate, and
b) curing the applied polyurea composition.