Patent GB-354748-A (GB)
Title: Improvements in the manufacture of cellulose ester or ether enamels or the like
IPC: C08J3/215
Filed: 1930-04-11
Abstract: Pigmented cellulose esters and ethers suitable for enamels, fillers, primers, &c., are obtained by causing a suspension of pigment in a suitable liquid to penetrate, under pressure, a more or less compressed mass of the ester &c.  For example, a quantity of the ester or ether wet with water is charged into a centrifuge and, after removing the bulk of the water, the centrifuge is slowed down and an aqueous slurry of pigment is run in by gravity or pressure feed; when all the pigment has been added, the speed is increased until the bulk of the liquid is removed.  To bring the mass into condition for working up into an enamel &c., it is treated with mixtures of industrial spirit and water containing progressively increasing quantities of spirit, followed, if desired, by treatment with isopropyl alcohol, toluol, xylol or other non-solvent for the ester &c.  The contents of the centrifuge are removed and stored or dispersed in a suitable solvent mixture with suitable gums, softeners, plasticizers, inhibitors, &c.  An hydraulic press may be used instead of a centrifuge.  In an example, water wet nitrocellulose is pigmented with an aqueous suspension of Prussian blue, the water being subsequently displaced by industrial spirit. Cellulose esters and ethers include the nitrate and acetate, and methyl, ethyl and benzyl cellulose.  Pigments include blanc fixe, chrome yellow and green, Prussian blue, lakes, lithopone, iron oxide with or without dyestuffs or precipitated organic or inorganic dyestuffs.  The ratio of pigment to ester or ether may range from 4-300 parts of dry pigment to every 10 parts of dry ester &c.ALSO:Pigmented cellulose esters and ethers suitable for enamels, fillers, primers, &c., are obtained by causing a suspension of pigment in a suitable liquid to penetrate, under pressure, a more or less compressed mass of the ester &c.  For example, a quantity of the ester or ether wet with water is charged into a centrifuge and, after removing the bulk of the water, the centrifuge is slowed down and an aqueous slurry of pigment is run in by gravity or pressure feed; when all the pigment has been added, the speed is increased until the bulk of the liquid is removed.  To bring the mass into condition for working up into an enamel &c., it is treated with mixtures of industrial spirit and water containing progressively increasing quantities of spirit, followed, if desired, by treatment with isopropyl alcohol, toluol, xylol or other non-solvent for the ester &c.  The contents of the centrifuge are removed and stored or dispersed in a suitable solvent mixture with suitable gums, softeners, plasticizers, inhibitors, &c.  An hydraulic press may be used instead of a centrifuge.  In an example, water wet nitrocellulose is pigmented with an aqueous suspension of Prussian blue, the water being subsequently displaced by industrial spirit. Cellulose esters and ethers include the nitrate and acetate, and methyl, ethyl and benzyl cellulose.  Pigments include blanc fixe, chrome yellow and green, Prussian blue, lakes, lithopone, iron oxide with or without dyestuffs or precipitated organic or inorganic dyestuffs.  The ratio of pigment to ester or ether may range from 4-300 parts of dry pigment to every 10 parts of dry ester &c.