Patent GB-441391-A (GB)
Title: Cellulose-coated materials and their manufacture
IPC: C09D101/10
Filed: 1934-07-19
Abstract: In a process for the manufacture of finely divided solids coated with cellulose suitable for use as fillers or pigments, e.g. in paints or rubber, the finely divided solid e.g. silicia or titanium dioxide is supended in an aqueous solution of an alkali soluble salt of a cellulose mono-ester of a dicarboxylic acid such as phthalic acid, the ester then being hydrolyzed preferably by heating, with agitation, above 50 DEG  C.  The coated solid which does not form into hard aggregates may be separated by filtration and coloured by dyeing the cellulose coating with a suitable dyestuff. Suitable solids are those ordinarily used as fillers, e.g. barytes, alumina, whiting, clays, silica talc, asbestos, magnesium carbonate, lithopone, zinc oxide, and titanium dioxide.  Suitable cellulosic compounds are the sodium, potassium, lithium and ammonium salts of the compounds obtained by esterifying cellulose with anhydrides of dicarboxylic acids, such as phthalic acid, succinic acid, quinolinic acid, adipic acid or maleic acid, in the presence of tertiary amines, e.g. pyridine with or without a catalyst.  In an example 5 parts of cellulose phthalic acid were suspended in 150 parts of water and about 10 parts of 30 per cent sodium hydroxide added in about 30 minutes.  The mixture was agitated violently for 30 minutes, and to it was added a mixture of 100 parts of silica (200 mesh) and 50 parts of water.  The whole was heated to 80 DEG  C. with vigorous agitation for 10 minutes, and the solid matter filtered and dried at 60 DEG  C. in vacuo.  A similar example is quoted employing titanium dioxide, 50 parts of the product being afterwards suspended in 200 parts of water with 0,2 parts of sodium hydrosulphite, the suspension being agitated and heated to about 55 DEG  C.  A vat was separately prepared consisting of 5 parts of sodium hydroxide, 8 parts of sodium hydrosulphite, 2,5 parts of Ponsol Brilliant Blue R paste (Colour Index No. 1106) and 100 parts of water heated to 50 DEG  C. and stirred.  The vatted dye was added to the suspension of coated titanium dioxide, and the mixture stirred at 50--60 DEG  C. for 20 minutes.  The blue product was filtered off and washed with warm sodium perborate to fix the dyes.  Examples of other suitable vat dyes, and of methods employing sulphur dyes and azo dyes are also given.ALSO:In a process for the manufacture of finely divided solids coated with cellulose, suitable for use as fillers or pigments, e.g. in paints, the finely divided solid, e.g. silica or titanium dioxide is suspended in an aqueous solution of an alkali soluble salt of a cellulose mono-ester of a dicarboxylic acid such as phthalic acid, the ester then being hydrolyzed preferably by heating, with agitation, above 50 DEG  C.  The coated solid which does not form into hard aggregates may be separated by filtration and coloured by dyeing the cellulose coating with a suitable dyestuff. Suitable solids are those ordinarily used as fillers, e.g. barytes, alumina, whiting, clays, silica, talc, asbestos, magnesium carbonate, lithopone, zinc oxide, and titanium dioxide. Suitable cellulosic compounds are the sodium, potassium, lithium and ammonium salts of the compounds obtained by esterifying cellulose with anhydrides of dicarboxylic acids, such as phthalic acid, succinic acid, quinolinic acid, adipic acid or maleic acid, in the presence of tertiary amines, e.g. pyridine with or without a catalyst.  In an example 5 parts of cellulose phthalic acid were suspended in 150 parts of water and about 10 parts of 30 per cent sodium hydroxide added in about 30 minutes.  The mixture was agitated violently for 30 minutes, and to it was added a mixture of 100 parts of silica (200 mesh) and 50 parts of water.  The whole was heated to 80 DEG  C. with vigorous agitation for 10 minutes, and the solid matter filtered and dried at 60 DEG  C. in vacuo.  A similar example is quoted employing titanium dioxide, 50 parts of the product being afterwards suspended in 200 parts of water with 0.2 parts of sodium hydrosulphite, the suspension being agitated and heated to about 55 DEG  C.  A vat was separately prepared consisting of 5 parts of sodium hydroxide, 8 parts of sodium hydrosulphite, 2.5 parts of Ponsol Brilliant Blue R paste (Colour Index No. 1106) and 100 parts of water heated to 50 DEG  C. and stirred.  The vatted dye was added to the suspension of coated titanium dioxide, and the mixture stirred at 50--60 DEG  C. for 20 minutes.  The blue product was filtered off and washed with warm sodium perborate to fix the dyes.  Examples of other suitable vat dyes, and of methods employing sulphur dyes and azo dyes are also given.ALSO:In a process for the manufacture of finely divided solids coated with cellulose, suitable for use as fillers or pigments, e.g. in paints or rubber, the finely divided solid, e.g. silica or titanium dioxide is suspended in an aqueous solution of an alkali soluble salt of a cellulose mono-ester of a dicarboxylic acid such as phthalic acid, the ester then being hydrolized preferably by heating, with agitation, above 50 DEG  C.  The coated solid which does not form into hard aggregates may be separated by filtration and coloured by dyeing the cellulose coating with a suitable dyestuff. Suitable solids are those ordinarily used as fillers, e.g. barytes, alumina, whiting, clays, silica, talc, asbestos, magnesium carbonate, lithopone, zinc oxide, and titanium dioxide. Suitable cellulosic compounds are the sodium, potassium, lithium and ammonium salts of the compounds obtained by esterifying cellulose with anhydrides of dicarboxylic acids, such as phthalic acid, succinic acid, quinolinic acid, adipic acid or maleic acid, in the presence of tertiary amines, e.g. pyridine with or without a catalyst.  In an example, 5 parts of cellulose phthalic acid were suspended in 150 parts of water and about 10 parts of 30 per cent sodium hydroxide added in about 30 minutes.  The mixture was agitated violently for 30 minutes, and to it was added a mixture of 100 parts of silica (200 mesh) and 50 parts of water.  The whole was heated to 80 DEG  C. with vigorous agitation for 10 minutes, and the solid matter filtered and dried at 60 DEG  C. in vacuo.  A similar example is quoted employing titanium dioxide, 50 parts of the product being afterwards suspended in 200 parts of water with 0,2 parts of sodium hydrosulphite, the suspension being agitated and heated to about 55 DEG  C.  A vat was separately prepared consisting of 5 parts of sodium hydroxide, 8 parts of sodium hydrosulphite, 2,5 parts of Ponsol Brilliant Blue R paste (Colour Index No. 1106) and 100 parts of water heated to 50 DEG  C. and stirred.  The vatted dye was added to the suspension of coated titanium dioxide, and the mixture stirred at 50-60 DEG  C. for 20 minutes.  The blue product was filtered off and washed with warm sodium perborate to fix the dyes.  Examples of other suitable vat dyes, and of methods employing sulphur dyes and azo dyes are also given.