Ciba Specialty Chemicals Corporation

Gill Jennings & Every Llp

William Walker

John Whitworth

Jonathan Campbell

Robert M O'Neil

Howard Roger Dungworth

Michael Heneghan

James Philip Taylor

Alan Platt

John Mark Plonka

Karen O'Donoghue

Ian Street

Ann Hunt

The present invention provides a composition, which comprises an aqueous solvent and forms a transparent colorless coating, which yields markings of high contrast on exposure to energy. It also provides a process for the preparation of these compositions, substrates coated with these compositions and a process for their preparation, a process for preparing marked substrates using these compositions and marked substrates obtainable by the latter process.

Aqueous and transparent coatings for marking substrates

New color developers, new mixture comprising it, its processes for preparation, heat sensitive recording compositions and materials comprising the novel developers and mixtures as well as their uses in heat sensitive recording materials.

Heat sensitive recording material

A method for the production of a keto acid having the general formula ##STR1## wherein R1 and R2 independently represent a straight or branched chain alkyl of 1-18 carbon atoms, a cycloalkyl of 4-8 carbon atoms or a phenyl, each of which may be substituted by at least one substituent selected from the group consisting of halogen atoms and alkyls having 1-4 carbon atoms, an aralkyl of 7-10 carbon atoms, alkoxyalkyl having 2-20 carbon atoms, tetrahydrofuryl alkyl, alkylcarboxy alkyl, alkylcarboxy benzyl, or R1 and R2 together with the adjacent nitrogen atom may form a heterocyclic ring, or one of R.sub.1 and R.sub.2 is hydrogen, but R1 and R2 may not simultaneously be methyl or ethyl or benzyl which comprises reacting a m-amino phenol having the general formula ##STR2## wherein R1 and R2 are the same as above, with phthalic anhydride, in an organic solvent in an amount of less than 0.5 parts by weight per part of m-amino phenol.

Production of keto acids

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Manchester, United Kingdom

William Walker