GB441716A - Improved manufacture of nitrocellulose lacquers - Google Patents

Abstract

In a manufacture of clear-drying nitrocellulose lacquers a commercial ester-soluble collodion cotton of any degree of viscosity and having a nitrogen content of 11,5--12,0 per cent is dissolved in a solvent consisting of an anhydrous mixture of absolute alcohol and an aromatic hydrocarbon the alcohol content of the solvent varying between 50 and 95 per cent. Preferably the lacquer contains equal parts by weight of absolute alcohol and benzene, and the collodion cotton advantageously has a nitrogen content of 11,8--11,9 per cent. A small proportion of a "true" solvent, e.g. butyl acetate, not exceeding 4 per cent may be added. The lacquer may also contain a softener and/or a resin, and also, if desired a pigment or a soluble dyestuff. A lacquer known under the Registered Trade Mark "Zapon" has the following composition:--7,5 per cent ester-soluble nitrocotton (11,62 per cent N) of high viscosity moistened with butyl or ethyl alcohol to the extent of 35 per cent; 91,5 per cent of a 1 : 1 mixture of absolute alcohol and benzene, and 1 per cent of dibutyl phthalate. A dipper lacquer contains 13,5 per cent of ester-soluble nitro cotton (N=11,8 per cent) of low viscosity moistened with butyl or ethyl alchol to the extent of 35 per cent together with either 2,5 per cent tricresyl phosphate, 81,0 per cent of 1 : 1 absolute alchol-benzene mixture and 3,0 per cent butyl acetate or 2,5 per cent dibutyl phthalate, 82,0 per cent of 1 : 1 absolute alcohol-benzene mixture and 2,0 per cent of ethylglycolacetate. A third example of a dipping lacquer is given in the Specification. The Specification as open to inspection under Sect. 91 comprises an example of a lacquer in which the alcohol exceeds 95 per cent of the alcohol-benzene mixture. It also states that the small proportion of true solvent is added in substitution for an equal proportion of benzene. This subject-matter does not appear in the Specification as accepted.