Patent ID: 8227525
Filing Date: 2012-07-24
Classification: C09B,C09D,Y10T

Abstract:
1. A process for purifying a composition comprising: i) an encapsulated pigment comprising a pigment and an encapsulant material comprising a cross-linked dispersant; ii) a liquid medium; and iii) free dispersant; said process comprising removal of at least some free dispersant from the composition using a membrane having a molecular weight cut-off of 3 to 30 times the weight average molecular weight of the dispersant prior to cross-linking, with the proviso that at least one of conditions a), b) and c) are met: a) the pigment is not silicon dioxide; b) the cross-linked dispersant is not cross-linked polyethyleneimine; and c) the cross-linked dispersant is not a dispersant which has been cross-linked with bis-ethene,1,1′-[methylene bis(sulfonyl)] wherein prior to cross-linking the dispersant is polymeric and has a weight averaged molecular weight of from 5,000 to 100,000.