GB1382989A - Spirit-reproducing carbon papers - Google Patents

Abstract

1382989 Spirit-reproducing carbon paper LAMSON INDUSTRIES Ltd 9 Dec 1971 [16 Dec 1970 14 May 1971] 57051/71 and 57052/71 Divided out of 1371091 Heading D2B A carbon paper for use in the preparation of a master copy to be used in a spirit-reproducing process comprises a support material carrying a substantially colourless coating contaming a colour former of the formula: wherein A and B each independently represents an optionally substituted, 1, 4-arylene residue; each of R<SP>1</SP> and R<SP>8</SP> independently represents a H atom or an optionally substituted alkyl, cycloalkyl, aralkyl, or aryl radical or forms part of a divalent organic chain which together with the attached N atom constitutes a heterocyclic ring; each of R<SP>2</SP> and R<SP>4</SP> may be the same as each of R<SP>1</SP> and R<SP>3</SP> but not a H atom; X represents a H atom, or an optionally substituted alkyl, cycloalkyl, aralkyl, or aryl radical or an optionally substituted saturated or unsaturated heterocyclic radical; Y is attached to a C atom in the compound and represents a group capable of allowing the compound to exist in ionic form, and n is a whole number. The support material may be paper, optionally provided with a barrier coating, or a plastics film e.g. of polypropylene, or polyethylene terephthalate. When the coated surface of the carbon paper is placed in contact with one surface of a master copy sheet and the other surface is typed on, a colourless reverse image is produced on the first-mentioned surface of the master copy sheet. This surface is brought into contact successively with sheets of copy paper moistened with a copying fluid in the presence of an electron-accepting substance. The latter substance may be present in the copying,fluid or on the copy paper. Thus, the copying fluid may contain an organic acid e.g. tannic, tartaric, salicylic, anthranitic, or benzoic acid or an inorganic acid e.g. HCl. Where the substance is present on the paper it may be an acid mineral e.g. attapulgite, calcium sulphate or an acid-treated coating e.g. containing phosphotungstic and phosphomolybic acids. In a typical example, a barrier-coated tissue is coated with a composition containing bis-(pdimethylaminophenyl) methane-α-benzyloxym-sodium carboxylate, carnauba wax, petroleum jelly, and mineral oil. Copies are made using a copying fluid-impregnated paper, the copying fluid containing ethanol, benzyl alcohol, and salicylic acid.