| 摘要 |
The invention is directed to a block copolymer with the following representative structure:R1-X-[[R2-N=C=N-R2-]n[-X-R3-X]p-[R2-N=C=N-R2]r]mX-R1Where: m=1 to 20 n=1 to 20 p=0 or 1 R1=A monomeric or polymeric species containing only one functional group reactive with an isocyanate group. This species may also have another reactive functional group that is not reactive with a carbodiimide functionality such as an alkoxy silane. R2=The radical from any available aliphatic, cycloaliphatic or shielded aromatic diiocyanate. R3=Preformed polymer blocks such as a polyester, polyacrylate, polyurethane, polyether, polyethylene, polycarbonate, polyurea polysiloxane or similar hybrids. X=any combination of: The copolymer may be used in various automotive paint compositions. The resin may be prepared by first synthesizing the desired blocks, the polycarbodiimide blocks and the modifying blocks, then link them together. The resin may also be prepared by forming the polycarbodiimide directly onto the modifying blocks. The latter approach is the preferred one. The modifying blocks are prepared in the conventional manner for the chemistry and the choice of the modifying blocks depend on the application. For proper topcoat wetting, it is desired that some portion of the modifying blocks be highly polar. |
