Carbonless copying papers - with colour components encapsulated in polyadduct from tri:keto-oxadiazine di-or tri-isocyanate

摘要

copying papers based on micro-encapsulated colour components are made from a capsule wall material consisting of a polyadduct of an isocyanate of formula (I), (where R is a divalent aliphatic gp; X is O or double bond N-R-NCO) and a tetra- or pent-amine. The micro-capsule walls are impermeable to the colour components and their solvent, break only when pressure is applied during writing, do not agglomerate in suspension and are unaffected by drying at 100 degrees C. The isocyanates have excellent solubility in many solvents, allowing dye solvents causing minimum pollution to be used. Micro-capsule suspensions are stable during storage and transport, and allow very good and uniform coating of paper.