Thermosensitive material for recording or copying sheets - contains electronegatively substd. mono- or poly:aldehyde or its reaction prod. with hydroxy cpd. as developer

摘要

A thermosensitive material for recording or copying comprises a colour-forming reaction system in which the colour developer is a mono- or polyaldehyde which is electronegatively substd. and/or its reaction prod. with an organic cpd. contg OH gps. or its intermediate prods. Pref. the electronegative substituent is in electrometric interaction with an aldehyde gp. The mono- or polyaldehyde is pref. of formula (I) where Q is a residue of formula R, M, M-(R)n5 R-M-(R)n, M-R-M or M-R-M-(R)n, where R is opt. substd. and optd. unsatd. aliphatic residue and M is aromatic, aromatic-cycloaliphatic, aromatic heterocyclic or heterocyclic residue, opt substd, with aromatic prods.; Y is strongly electronegative substituent, Z is H or an acid gp. and m and n are 1-6. The developers are resistant to oxidn by atmos. oxygen and also to acids at 100 degrees C. They are stable at least up to their m pts. and partly distillable without decompsn. even under vacuum. They are colourless, odourless, water insoluble, soluble in inorganic solvents. They are resistant to migration and therefore inert to premature reaction. They are compatible with starch and cellulose and can therefore be combined with paper pulp.