Patent GB-604745-A (GB)
Title: Improvements in or relating to methods of preparing zein solutions directly from gluten
IPC: C08L89/00
Filed: 1943-12-24
Abstract: Solutions of prolamines, which may be used in coating compositions and are stable over a wide range of concentration and temperature are obtained by extracting gluten directly at 120-180 DEG  F. with a mixture of a hydroxylated organic solvent having a boiling point above 125 DEG  C. and a proportion of polar to non-polar radicals between the limits of polar to non-polar radicals of methanol and ethanol and another organic solvent having a boiling point below 125 DEG  C. and then removing a part of the latter solvent.  In a modification, the gluten is treated first with a solvent boiling below 125 DEG  C. selected from those which dissolve prolamines and the hydroxylated solvent is added to the extract before distillation of some of the low boiling solvent.  The high boiling solvent having a proportion of polar to non-polar radicals within the specified range may be replaced by benzyl alcohol, cyclohexanol, furfurylalcohol, tetrahydrofurfurylalcohol, ethyleneglycol monomethyl and ethyl ethers, diethyleneglycol monomethyl and ethyl ethers and diacetone alcohol.  Specified high boiling solvents which may be used are diethylene glycol, propyleneglycol, triethyleneglycol and mixtures thereof containing ethylene glycol or glycerine.  The low boiling solvent materials are preferably solvents for prolamines such as anhydrous methanol or aqueous alcohols, e.g. azeotropic mixtures of ethyl and isopropyl alcohol.  Non-solvents may be present such as ethylene dichloride, trichlorethylene, ethyl acetate, benzene, cyclohexane, carbontetrachloride, acetone and methylethylketone, dioxane, butylalcohol, 1 : 5-dichlorpentane, dichlorethylether, or hydrogenated naphtha.  The resulting solutions yield coatings suitable for paper, textiles, wood, glass or regenerated cellulose and may be used for laminating paper, cloth, wood, glass, felt, metal foils or regenerated cellulose. The coating may be modified by the addition of dioxane, ketones, e.g. dibutylketone, esters, e.g., ethylbutyrate, glycoldiacetate, or glycol ether-esters, ethers, e.g. diethyleneglycolmonobutylether, alcohols, e.g. amyl, octyl, cetyl and myristyl alcohols, hydrocarbons, e.g., xylene, cyclohexane, chlorinated compounds, e.g., chlorbenzene, dichlorbenzene, furane derivatives, e.g. furfuryl acetate and furfurylalcohol, plasticisers, e.g. dimethylphthalate and tricresylphosphate, fatty acids, e.g. oleic, linseed or lauric fatty acids, glycerides, e.g. chinawood oil, natural and synthetic resins, e.g. resin, copal, phenol-aldehyde, urea-aldehyde, glycerine-phthalic anhydride and vinyl resins, cellulose derivates, e.g. nitrocellulose, cellulose acetate, ethylcellulose, fillers, e.g. cork, mica, sawdust, chalk, magnesite, clay, bentonite, charcoal, dyes and pigments.  The addition of rosin, amine soaps and amines such as mono- and triethanolamine to the prolamine solutions is mentioned.ALSO:Solutions of prolamines obtained by extracting gluten directly at 120-180 DEG  F. with a mixture of a hydroxylated organic solvent having a boiling point above 125 DEG  C. (see Group III), yield coatings suitable for paper, textiles, wood, glass or regenerated cellulose and may also be used for laminating paper, cloth, wood, glass, felt, metal foils or regenerated cellulose.  The coating may be modified by the addition of dioxane, ketones, e.g. dibutylketone, esters, e.g., ethylbutyrate, glycoldiacetate, or glycol ether-esters, ethers, e.g. diethyleneglycolmonobutylether, alcohols, e.g. amyl, actyl, cetyl and myristyl alcohols, hydrocarbons, e.g. zylene cyclohexane, chlorinated compounds, e.g. chlorbenzene, dichlorbenzene, furane derivatives, e.g. furfuryl acetate and furfurylalcohol, plasticizers, e.g. dimethylphthalate and tricresylphosphate, fatty acids, e.g. oleic, linseed or lauric fatty acids, glycerides, e.g. chinawood oil, natural and synthetic resins, e.g. resin, copal, phenolaldehyde, urea - aldehyde, glycerine - phthalic anhydride and vinyl resins, cellulose derivatives, e.g. nitrocellulose, cellulose, acetate ethylcellulose, fillers, e.g. cork, mica, sawdust, chalk, magnesite, clay, bentonite, charcoal, dyes and pigments.ALSO:Solutions of prolamines, which are stable over a wide range of concentration and temperature are obtained by extracting gluten directly at 120-180 DEG F. with a mixture of a hydroxylated organic solvent having a boiling point above 125 DEG  C. and a proportion of polar to non-polar radicals within the range extending between the limits of polar to non-polar radicals of methanol and ethanol and another solvent material having a boiling point below 125 DEG  C. and then removing a part of the latter solvent.  In a modification, the gluten is treated first with a solvent boiling below 125 DEG  C. selected from those which dissolve prolamines and the hydroxylated solvent is added to the extract before distillation of some of the low boiling solvent. The high boiling solvent having a proportion of polar to non-polar radicals within the specified range may also be replaced by benzyl alcohol, cyclohexanol, furfurylalcohol, tetrahydrofurfurylalcohol, ethyleneglycol monomethyl and ethyl ethers, diethyleneglycol monomethyl and ethyl ethers and diacetone alcohol.  Specified high boiling solvents which may be used are diethylene glycol, propyleneglycol, triethyleneglycol and mixtures thereof containing ethylene glycol or glycerine.  The low boiling solvent materials are preferably solvents for prolamines such as anhydrous methanol or aqueous alcohols, e.g. azeotropic mixtures of ethyl and isopropyl alcohol.  Non-solvents may be present such as ethylene dichloride, trichlorethylene, ethylacetate, benzene, cyclohexane, carbontetrachloride, acetone and methylethylketone, dioxane, butylalcohol, 1 : 5-dichlorpentane, dichlorethylether, or hydrogenated naphtha. The resulting solutions are used in the manufacture of coating compositions, laminated materials, and printing inks.  In detailed examples, powdered gluten is extracted with a solvent, e.g. 91 per cent isopropyl alcohol at 180 DEG  F. to extract the zein-containing proteins.  After filtering, the high boiling solvent, e.g. propyleneglycol, is added and the solution heated at 250 DEG  F. until the isopropyl alcohol is removed.  In other examples, the gluten is treated with a mixture of the high and low boiling solvents and the latter then removed by distillation. An example also describes the preparation of an ink by mixing a solution of zein in diethyleneglycol with carbon black, degras and dry alkali blue.