Patent GB-330957-A (GB)
Title: Improvements in the manufacture and production of finely comminuted masses from cellulose derivatives
IPC: C08J3/12
Filed: 1929-03-16
Abstract: 330,957. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges). March 16, 1929. Compositions containing cellulose esters and ethers.-Cellulose derivatives, particularly those having a fibrous structure are finely comminuted by first mechanically tearing by friction, if desired, in the presence of resin, or non-solvent liquid containing an amount of solvents or gelatinizing agents insufficient for gelatinizing the cellulose derivative, but in the absence of solid foreign matter or of agents chemically attacking the cellulose derivatives, and then' grinding the mass obtained, if desired, in the presence of protective colloids, dispersing agents, dyestuffs, fillers, resins, or non-solvent liquids. Solvents or softening agents may be added in emulsified form. The tearing process may be applied to cellulose triacetate, cellulose acetate soluble in acetone, cellulose aceto-butyrate, ethyl cellulose, ethyl benzyl cellulose, or ethyl butyl cellulose in the dry state. When using nitrocellulose it is preferred to add a moistening agent such as water, alcohols, hydrocarbons. There may be added protective colloide such as gelatine, methyl cellulose, water-soluble resinous condensation products of urea and formaldehyde, or polymerized vinyl alcohol, or emulsifiers such as resin soaps, alkali metal salts of propylated or butylated naphthalene sulphonic acids, or of the acids of fats and oils, or salts of these substances with organic bases such as triethylamine mixed, if desired, with mono- or diethylamine. There may also be added dissolved dyestuffs and like agents which do not reduce the, mechanical strength of the particles of cellulose derivatives nor react chemically therewith. The tearing process may be carried out by means of a pair .of closely arranged rotating friction rollers between which the material is passed in very thin layers. The rollers may be heated and may be rotated in opposite directions and laterally displaced in opposite directions. The subsequent grinding operation is carried out in apparatus such as a ball mill, or hopper mill. When pigments or fillers are added the amounts of gelatinizing agents or solvents with the non-solvents may frequently be increased to some extent. The products obtained may be used in the manufacture of coatings and plastic masses. In an example, nitrocellulose or acetylcellulose moistened with water is passed several times through a friction roller mill at room temperature. The laminated mass is then finely ground in a ball mill with the addition of water or methyl cellulose solution, or a solution of the sodium salt of a butylated naphthalene sulphonic acid together with methyl cellulose, butyl stearate, and dibutyl phthalate, or castor oil and tricresyl phosphate. Resins such as condensation products obtained from cyclic ketones mav be dissolved in the softening agents in the cold or while heating. In other examples, benzyl, ethyl, or butyl cellulose is passed between friction rollers and then after the addition of water is ground in a ball mill. The paste obtained is incorporated with methyl cellulose solution and an emulsion of dibutvl phthalate with water, methyl cellulose, and the sodium salt of butylated naphthalene sulphonic acid. The mixture is homogenized by further grinding in a ball mill and if desired pigments may be added. The Provisional Specification describes the addition of pigments such as Lithol Fast Scarlet R or Lithol Red R to the cellulose derivatives before the mechanical tearing process.