HOW CELLULOID IS MADE

International Tract and Missionary Society · Oakland, California · Oct 14, 1889

FromSigns of the Times, Vol. 15, No. 39.

HOW CELLULOID IS MADE.

WHILE everybody has heard of or seen or used celluloid, only a few know what it is composed of or how it is made. The following is a description of the process carried out in a factory near Paris, for the production of celluloid: A roll of paper is slowly unwound, and at the same time is saturated with a mixture of five parts of sulphuric acid and two parts of nitric acid, which falls upon the paper in a fine spray. This changes the cellulose of the paper into pyroxylin (gun cotton). The excess of the acid having been expelled by pressure, the paper is washed with plenty of water, until all traces of acid have been removed. It is then reduced to a pulp, and passes on to the bleaching trough. Most of the water having been got rid of by means of a strainer, the pulp is mixed with from twenty to forty per cent. of its weight in camphor, and the mixture thoroughly triturated under millstones. The necessary coloring having been added in the form of powder, a second mixing and grinding follows. The finely divided pulp is then spread out in thin layers on slabs; and from twenty to twenty-five of these layers are placed in a hydraulic press, separated from one another by some sheets of thick blotting paper, and are subjected to a pressure of 150 atmospheres, until all traces of moisture have been got rid of. The matter is then passed between rollers heated to between 140° and 150° Fahrenheit, whence it issues in the form of elastic sheets.—The Inventor.