Patent GB-612706-A (GB)
Title: Improvements in or relating to flatting agents for use in coating compositions
IPC: C09D7/00
Filed: 1944-12-04
Abstract: A flatting agent comprises a soap of a metal of the class consisting of aluminium, zinc, magnesium and the alkaline earth metals, and rosin which has been chemically treated to increase its melting point, coated with a film deposited from an aqueous solution of a water soluble colloidal organic film-forming agent which is insoluble in liquid hydrocarbons.  The rosin may be modified by hydrogenation, combination with phenol-aldehyde resin or by a Diels-Alder reaction to give as great an increase in melting point and reduced solubility as possible.  The film-forming materials include methyl cellulose and proteins such as albumin, casein, gelatin, water-soluble ureaformaldehyde resins, and water-soluble gums such as dextrin, gum tragacanth, and gum arabic, preferably converted to the water-insoluble state after being coated on the soap particles.  In one example, a cold aqueous solution of methyl cellulose and a solution of aluminium sulphate are added to a saponified maleic anhydride treated rosin and after boiling to precipitate the methyl cellulose the product is ground to separate the pigment size particles which are then ready for incorporation in a coating composition.  Another example indicates the coating of the already precipitated and washed aluminium soap of the treated rosin with methyl cellulose.  When the soap is to be coated with casein, a solution of casein in water is prepared with the aid of ammonium hydroxide, the pH of the solution being adjusted to between 10 and 10.5.  Examples are given of lacquers containing the flatting agent (6 per cent), nitrocellulose, Damar resin, tricresyl phosphate and solvents consisting mainly of hydrocarbons and aliphatic esters; varnishes containing the flatting agent (7 per cent) phenolic varnish base and mineral spirits; an alkyd-urea varnish and an artificial leather coating.ALSO:A flatting agent comprises a soap of a metal of the class consisting of aluminium, zinc, magnesium and the alkaline earths, with rosin which has been chemically treated to increase its melting point, coated with a film deposited from an aqueous solution of a water-soluble colloidal film-forming agent which is insoluble in liquid hydrocarbons.  The rosin may be modified by hydrogenation, combination with phenol-aldehyde resin or by a Diels-Alder reaction. The film-forming materials include methyl cellulose and proteins such as albumen, casein and gelatin, water-soluble urea-formaldehyde resins and water-soluble gums such as dextrin, gum tragacanth and gum arabic, preferably converted to the water-insoluble state after being coated on the soap particles.  In one example, a cold aqueous solution of methyl cellulose and a solution of aluminium sulphate are added to a saponified maleic anhydride treated rosin and after boiling to precipitate the methyl cellulose the product is ground to separate the pigment size particles which are then ready for incorporation in a coating composition.  Another example indicates the coating of the already precipitated and washed aluminium soap of the treated rosin with methyl cellulose.  Examples are given of lacquers containing the flatting agent, nitrocellulose, Dammar resin, tricresyl phosphate and solvents consisting mainly of hydrocarbons and aliphatic esters; varnishes containing the flatting agent, phenolic varnish base and mineral spirits; an alkyd-urea varnish and an artificial leather coating.