Crosslinkable composition
An RMA crosslinkable composition for making thick coating layers having at least one crosslinkable component comprising reactive components A and B each including at least 2 reactive groups wherein the at least 2 reactive groups of component A are acidic protons (C—H) in activated methylene or methine groups, and the at least 2 reactive groups of component B are activated unsaturated groups (C═C), to achieve crosslinking by Real Michael Addition reaction, the composition further including a base catalyst (C), an X—H group containing component (D) that is also a Michael addition donor reactable with component B under the action of catalyst C, wherein X is C, N, P, O or S and a sag control component (E). A crosslinkable composition is also disclosed for preparing thick coating layers having a dry thickness of at least 70 mu having a surface appearance and hardness of the resulting cured composition.
1. A composition for use in a process for the preparation of a RMA crosslinkable composition, obtainable by in situ precipitation of a sag control agent (SCA) in a RMA donor resin comprising component A having at least 2 acidic protons C—H in activated methylene or methine or in a RMA acceptor resin comprising component B having at least 2 activated unsaturated groups by in-situ reacting an isocyanate with an amine compound.
2. The composition of claim 1 , wherein the SCA is prepared in situ in the RMA donor resin.
3. The composition of claim 1 obtainable by a process comprising in-situ reacting (a) a symmetrical aliphatic or homocyclic diisocyanate and (b) a monoamine or diamine containing at least a primary amino group and an ether group.
4. The composition of claim 1 , wherein the sag control agent is based on isocyanurate.
5. The composition of claims 1 obtainable by a process comprising in-situ reacting one or more polyamines with one or more monoisocyanates to form a polyurea compound, wherein at least one of the mono-or polyamine or mono-or polyisocyanate is optically active, not as racemic mixture, having a chiral carbon atom adjacent to an amine or isocyanate group.
6. The composition of claims 1 obtainable by a process comprising in-situ reacting to form a first polyurea reaction product a first polyisocyanate with a first amine and a second polyurea reaction product of a second polyisocyanate with a second amine different from the first polyurea reaction product precipitated in the presence of the colloidal particles of the first reaction product.
7. The composition of claim 1 obtainable by a process comprising
a. Providing a solution in an organic solvent of a donor resin comprising component A having at least 2 acidic protons C—H in activated methylene or methine or of a acceptor resin comprising component B having at least 2 activated unsaturated groups, and subsequently
b. Providing in said solution a first polyurea reaction product in the form of anisotropic colloidal particles, by mixing a first polyisocyanate and a first amine and react to form the first polyurea in-situ in the form of anisotropic colloidal particles, and
c. adding a second polyisocyanate and/or a second amine to form a second polyurea. reaction product different from the first polyurea reaction product, and wherein the second polyurea reaction product is precipitated in the presence of colloidal particles of the first reaction product.
8. The composition of claim 7 obtainable by a process comprising;
a. Providing a solution in an organic solvent of a component A having at least 2 acidic protons C—H in activated methylene or methine, and subsequently
b. Providing in said solution a first polyurea reaction product in the form of anisotropic colloidal particles, by mixing a first polyisocyanate and a first amine and react to form the first polyurea in-situ in the form of anisotropic colloidal particles, then
c. Mixing component B having at least 2 activated unsaturated groups before or after step d) and
d. Adding a second polyisocyanate and/or a second amine to form a second polyurea reaction product different from the first polyurea reaction product, and wherein the second polyurea reaction product is precipitated in the presence of colloidal particles of the first reaction product.
9. A process for the manufacture of a RMA crosslinkable composition comprising:
a. Providing a composition according to claim 1 ,
b. adding a catalyst,
c. wherein the composition comprises between 0.1 and 80 wt % of solvent
d. optionally adding at least 0.5 wt % of water.
10. A coating composition comprising RMA crosslinkable composition obtainable by the process of claim 9 and further coating additives.