Patent GB-610647-A (GB)
Title: Improvements in or relating to artificial filaments, films and similar materials
IPC: D01F4/00
Filed: 1946-04-12
Abstract: Artificial filaments, films, bristles, self-supporting foils, films, sheets and similar materials are obtained by casting or extruding into a gaseous or liquid setting medium an organic solvent solution containing a complex formed between a protein colloid and an anion soap, a free acid of an anion soap, or a sulphonic acid containing a highly hydrophobic radical in the anion.  The protein complex may be obtained from gelatin, casein, albumen, or ground nut protein.  To obtain a complex of high solubility in organic solvents, the anion of the anion soap or sulphonic acid used should be as strongly hydrophobic as possible, the pH of the solution in which the complex is formed should be below the isoelectric point of the protein, the electrolyte concentration in the solution should be as low as possible, and the concentration of the anion soap should be as near the "inflexion point" as possible.  This point is taken as the concentration which produces the greatest relative precipitation of protein complex from an aqueous solution, and it is determined experimentally.  The free acids of the anion soaps may be used when the pH may be 2.0 to 3.0.  The anionic soap or similar compound may be a soluble salt of a long-chain-alkyl carboxylic acid, e.g. of oleic, ricinoleic, linoleic, stearic or palmitic acid, or it may be a soluble salt of a long-chain-alkyl sulphonic acid, a soluble salt of a sulphated higher fatty alcohol, e.g. of lauryl hydrogen sulphate, or a soluble salt of a sulphated secondary alcohol, or a salt of an alkylated aromatic sulphonic acid, or a soluble salt of a long-chain-alkyl ester of sulphated succinic acid.  Salts of alkali metals, ammonia, or amines may be used.  The anions may contain amino groups, e.g. sodium oleoyl amino ethane sulphonate.  The sulphonic acid may be a simple naphthol sulphonic acid or a more complex compound such as Kiton Fast Yellow 3G or Naphthalene Orange GS.  The organic solvent used to dissolve the protein complex may be methyl or ethyl alcohol, ethylene glycol mono-methyl ether, ethyl lactate, diacetone alcohol, or aqueous acetone, dioxane, chloroform, or mesityl oxide.  The organic liquid solutions of the protein complex may be used alone for the production of filaments and other products or they may be mixed with or added to solutions of other filament-forming materials, e.g. cellulose esters or ethers, polyvinyl compounds, polymethacrylates, alkyd resins and polyamides. In an example, casein is dissolved in water containing a little ammonia.  An acidified aqueous solution of dodecyl sodium sulphate is added so that the mixture has a pH of 2.2 to 3.0, and so that there are present five parts of casein to one part of the dodecyl sulphate. The casein complex which separates is filtered off and dissolved in ethyl alcohol.  The casein complex solution is extruded into an evaporative atmosphere and the filaments obtained are stretched as they are extruded. The twisted filaments are hardened by formaldehyde.  Air, steam or water vapour may be used as the evaporative medium.  Before hardening, the filaments may be further stretched, preferably in presence of a softening agent such as alcohol vapour.  The stretching may be followed by a shrinking treatment.  Delustred filaments may be obtained by including titanium dioxide, starch or other white pigment in the spinning solution or by adjusting the evaporative conditions in the region of the orifices. If the hardening step is omitted the filaments may be associated with other threads in fabrics and then dissolved or destroyed by the action of caustic alkali leaving patterned or effect fabrics. Specification 585,758 and 585,759, [both in Group XX], are referred to.ALSO:Artificial filaments, films, bristles, self-supporting foils, films, sheets and similar materials are obtained by casting or extruding into a gaseous or liquid setting medium an organic solvent solution containing a complex formed between a protein colloid and an anion soap, a free acid of an anion soap, or a sulphonic acid containing a highly hydrophobic radical in the anion.  The protein complex may be obtained from gelatin, casein, albumen or ground nut protein.  To obtain a complex of high solubility in organic solvents, the anion of the anion soap or sulphonic acid used should be as strongly hydrophobic as possible, the pH of the solution in which the complex is formed should be below the isoelectric point of the protein, the electrolyte concentration in the solution should be as low as possible, and the concentration of the anion soap should be as near the "inflexion point" as possible.  This point is taken as the concentration which produces the greatest relative precipitation of protein complex from an aqueous solution, and it is determined experimentally.  The free acids of the anion soaps may be used when the pH is low.  In the case of gelatin the pH may be 2.0 to 3.0.  The anionic soap or similar compound may be a soluble salt of a long-chain-alkyl carboxylic acid, e.g. of oleic, ricinoleic, linoleic, stearic or palmitic acid, or it may be a soluble salt of a long-chain-alkyl sulphonic acid, a soluble salt of a sulphated higher fatty alcohol, e.g. of lauryl hydrogen sulphate, or a soluble salt of a sulphated secondary alcohol, or a salt of an alkylated aromatic sulphonic acid, or a soluble salt of a long-chain-alkyl ester of sulphated succinic acid.  Salts of alkali metals, ammonia or amines may be used.  The anions may contain amino groups, e.g. sodium, oleoyl amino ethane sulphonate.  The sulphonic acid may be a simple naphthol sulphonic acid or a more complex compound such as Kiton Fast Yellow 3G or Naphthalene Orange GS.  In an example, casein is dissolved in water containing a little ammonia.  An acidified aqueous solution of dodecyl sodium sulphate is added so that the mixture has a pH of 2.2 to 3.0, and so that there are present five parts of casein to one part of the dodecyl sulphate.  The casein complex which separates is filtered off.