Patent ID: 8674006
Filing Date: 2014-03-18
Classification: C07D,C09B,C09D,G02B

Abstract:
1. A dispersion which is useful for electrophoretic displays comprising α) a bis-oxodihydro-indolylene-benzodifuranone colourant of the formula I wherein R R R or a cis-trans isomer thereof or a salt of such colourant or isomer having a salt-forming group, β) a polymeric dispersant comprising modified poly(meth)acrylate polymers obtained by the process comprising the steps a1) polymerizing in a first step one or more ethylenically unsaturated monomers in the presence of at least one nitroxylether having the structural element of the formula wherein X represents a group having at least one carbon atom and is such that the free radical X● derived from X is capable of initiating polymerization; or a2) polymerizing in a first step one or more ethylenically unsaturated monomers in the presence of at least one stable free nitroxyl radical of the formula and a free radical initiator; wherein at least one monomer used in the steps a1) or a2) is a C and a second step b) comprising the modification of the polymer or copolymer prepared under a1) or a2) by a transesterification reaction, an amidation, hydrolysis or anhydride modification or a combination thereof, and γ) a solvent which is suitable for dispersions used in electrophoretic displays.