Patent GB-380950-A (GB)
Title: Manufacture of plastic masses from cellulose acetates
IPC: C08L1/12
Filed: 1931-09-30
Abstract: Solid plastic masses are made from cellulose acetates, by dissolving in a sufficient proportion of one or more volatile solvents preferably slightly more than just suffices for complete dissolution, the cellulose acetate solution so obtained being concentrated either directly, or after mixing with softening agents, at a raised temperature, and if desired at reduced pressure, until there is obtained a solid, plastic, non-adhesive mass, which can be rolled out on heated rollers.  Softening agents, diluents which do not dissolve cellulose acetate, filling agents, dyestuffs, pigments, natural and artificial resins, other cellulose esters or ethers, particularly nitrocellulose which substantially increases the hardness of the product, may be added before, during or after concentration of the cellulose solution. The cellulose acetate solution is kept well stirred during concentration to avoid the formation of lumps, and may be filtered before concentration while still in a fluid condition, excess pressure being employed if desired.  A current of an inert gas may be used to assist concentration.  The softening agents may be added to the solvent, before the latter is added to the cellulose acetate.  In an example 50 kilos of acetyl cellulose, and 10 kilos of nitrocellulose are covered with 100 kilos of ethyl alcohol, and 100 kilos of acetone and the whole stirred till dissolution is complete. The solution is concentrated under reduced pressure at 40 DEG  C. until 150 kilos of solvent have been removed, 10 kilos of triacetin, 5 kilos of paratoluene sulphonamide, 5 kilos of iron black, \ba1/2\be kilo nigrosine are then added, and the mixture kneaded until homogeneous.  The mass is then worked up in known manner into plates, sheets or thin foils.  In another example ethyl cellulose is mixed with cellulose acetate together with fillers, softening agents, &c. in a similar manner to above.  This also results in a hard product. Specifications 290,801 and 318,818, [both in Class 70, Indiarubber &c.], are referred to.ALSO:Solid plastic masses are made from cellulose acetates, by dissolving in a sufficient proportion of one or more volatile solvents preferably slightly more than just suffices for complete dissolution, the cellulose acetate solution so obtained being concentrated either directly, or after mixing with softening agents, at a raised temperature, and if desired at reduced pressure, until there is obtained a solid, plastic, non-adhesive mass, which can be rolled out on heated rollers.  Softening agents, diluents which do not dissolve cellulose acetate, filling agents, dyestuffs, pigments, natural and artificial resins, other cellulose esters or ethers particularly nitrocellulose which substantially increases the hardness of the product, may be added before, during or after concentration of the cellulose solution. The cellulose acetate solution is kept well stirred during concentration to avoid the formation of lumps, and may be filtered before concentration while still in a fluid condition, excess pressure being employed if desired.  A current of an inert gas may be used to assist concentration.  The softening agents may be added to the solvent, before the latter is added to the cellulose acetate.  In an example 50 kilos of acetyl cellulose, and 10 kilos of nitrocellulose are covered with 100 kilos of ethyl alcohol and 100 kilos of acetone and the whole stirred till dissolution is complete.  The solution is concentrated under reduced pressure at 40 DEG  C. until 150 kilos of solvent have been removed, 10 kilos of triacetin, 5 kilos of paratoluene sulphonamide, 5 kilos of iron black, 1/2 kilo nigrosine are then added, and the mixture kneaded until homogeneous.  The mass is then worked up in known manner into plates, sheets or thin foils. In another example ethyl cellulose is mixed with cellulose acetate together with fillers softening agents, &c. in a similar manner to above.  This also results in a hard product. Specifications 290,801 and 318,818, [both in Class 70, Indiarubber &c.], are referred to.