GB469424A - Improvements in or relating to the manufacture of nitrocellulose - Google Patents

Abstract

Sheets of cellulose pulp having a thickness of two to eight hundredths of an inch and a compactness of 50--115 are subdivided and the chips so produced are treated at a temperature not substantially less than 40 DEG C. with a nitrating acid composition containing 50--75 per cent of nitric acid. The compactness is the ratio of the weight in pounds of 415,000 sq. ins. of the sheet to 100 times the thickness of the sheet in inches. Preferably, the sheets are of thickness 0,03--0,035 inches and of compactness 60--80, they are cut into chips one-eighth to one-sixteenth inch square, and the chips are nitrated with a mixture of sulphuric acid and water with 60 per cent of nitric acid at a temperature of 40--50 DEG C., the amount of mixed acid being 10 times the dry weight of cellulose. In an example, chips obtained by cutting purified wood cellulose sheets are dried to 1 per cent moisture content and treated with a nitrating mixture containing 60 per cent of nitric acid in a mechanical type of dipper pot. The charge is then dropped into a centrifuge and excess acid wrung out. The product is drowned in water, stabilized by heating in acid water, and then washed. In another example chips are cut from cellulose sheets having a compactness of 110. The nitrocellulose obtained by the process may be used in the production of lacquers for metal or wood, leather dopes, and camphor-alcohol plastics. Specification 336,235, [Class 2 (ii)], is referred to.