Patented Oct. 29, 1946 2,410,124 I UNITED STATES PATENT OFFICE PRODUCTION - OF PLASTICIZED PROLAMINE AND DERIVATIVE COMPOSITIONS Willard L. Morgan, Columbus, Ohio, assignor of one-half to A. E. Staley Manufacturing Com pany, Decatur, 111., a corporation of Delaware, and one-half to American-Maize Products Company, New York, N. Y., a corporation of Maine \ No Drawing. Application November 24. 1944. - I Serial No. 565,065 18 Claims. 1 This invention relates to plasticizers for pro lamines, and to the resultant plasticized pro. lamine and “prolamine-base’-’_ compositions. It is an object of this invention to provide novel plasticized “prolamine-base” compositions. ' ~ It is another object of this invention toprovide compositions with plasti novel “prolamine-base" (Cl. 106-153) - . 2 ticizers for this purpose have been proposed, but most of such prior art materials have exhibited low plasticizing activityor undesirable charac teristics such as incomplete compatibility, high melting point,‘ strong odors, water solubility or rapid loss by volatilization from the prolamine, thereby, and in other ways, resulting in composi cizers exhibiting highly desirable compatibility tions which are unsatisfactory commercially in and solvency for the prolamines, thus permitting one respect or another. the preparation directly ofv plastic masses, coat 10 In this invention there is set forth the surpris ings and ?lms with the prolamines. ing discovery that alkyl branched-chain ‘satu It is a still further object of this invention to rated and unsaturated organic fatty acids in provide novel “prolamine-base” compositions which the total number of carbon atoms in a having plasticizers for prolamines of improved molecule lies in the range 4 to 18, inclusive, func compatibility characteristics which compositions may be applied in solvents as adhesives or coat ings, or thus applied in forming ?lms or plastics. Other and ancillary objects of this invention 15 tion as remarkably effective plasticizers for pro lamines. Thus, for example, 2-methyl propenoic ’ acid, ,2-ethyl butanoic acid (2-ethyl butyric acid), 2-ethyl hexanoic acid (Z-ethyl caproic acid), will be'apparent from the detailed description 2-ethyl octanoic acid (2-ethyl caprylic acid), and examples thereof hereinbelow set forth. 2-ethy1 decanoic acid (Z-ethyl capric acid), 2-=tri The prolamines have long been established as 20 methyl acetic acid. (pivalic acid), 5-methyl hex exhibiting certain properties unique among the anoic acid (5-methyl caproic acid); 2-propyl bu proteins, and as such have been classi?ed by tanoic acid (2-propyl butyric acid), 2-octyl de workers dealing with proteins as a separate group canoic acid (2-octyl capric acid), are effective thereof. By de?nition, the prolamines are those 25 plasticizers for the prolamines.- Furthermore, proteins characterized by solubility in aqueous mixtures of these acids as, for example, 2-ethyl ethyl alcohol. They are found only in cereal butanoic and 5-methyl hexanoic acids, combined grains and, contrasted to other proteins, are high in any proportions whatever with each other con in the amino acid proline and amide nitrogen stitute e?ective prolamine plasticizers. The content, and are de?cient in free amino groups 30 branched-chain fatty acids may also be employed and in lysine. They are very nearly or entirely as plasticizers in prolamine plastics in combina insoluble in water and weak a/queous acid solu tion with other known plasticizers such as dibutyl tions, but are freely soluble in dilute alkali solu > tartrate or para toluene’ sulfonamide. tions in water. . The amount of plasticizer which may e?'ectively be Althoughlin the following description and ex with the prolamine to result in a amples I shall refer to the particular prolamine 35 incorporated useful, plasticized composition occupies an ex zein which is derived from corn, it is to be under~v tremely broad range of percentages based on total. stood that this invention is equally applicable to product composition, and the amount employed the other prolamines, and “prolamine-base” pro will depend upon the properties desired in the teins, that is, to hordein, derived from barley; to 40 plastic to be produced. For example, if 5 per ka?rin, derived from sorghum; to gliadin, which cent (bylweight of the resultant composition) of is derived from wheat; to secalin, derived from branched-chain fatty acid plasticizer be incor- rye, and to the cereal glutens generally; porated with, say, the prolamine zein, the plasti The diverse and potentially large-scale utiliza tion of plasticized prolamine compositions has 45 cized product is hard and tough in character. When on the other hand. increasingly greater long been attractive, and the discovery of satis percentages of plasticizer are incorporated with factory plasticizers for the prolamines in gen the zein, the resultant compositions exhibit in eral, and, in particular, for the prolamine zein creased flexibility and softness such that at a which is of industrial importance, has been the content of 50 percent by weight in the product, object of extensive investigation. Various plas 50 the plastics often resemble many rubber articles. 2,410,124 ' 4 3 ing; utilized for impregnating and coating, par manently soft and tacky. Fundamental product ticularly for grease and water-proo?ng purposes; and applied to the production of flexible ?lms, lacquers, wall and floor paints, deck enamels, grease and moisture-proof lacquers for applica~ When 80 to 95 percent by weight of the resultant composition is plasticizer, the products are per characteristics may be regarded, then, as a func tion of plasticizer content, and it therefore fol . .tion to metallic surfaces, protective varnishes for lows that the amount of plasticizer to be incor printed and other paper surfaces, adhesives, lami porated with a prolamine will be ‘determined by nated products of various types, plastic compo the use to which the product is to be put. Fur sitions, linoleum, oilcloth, and the like. These ther in this regard, it has been discovered that uses are, of course, cited as being illustrative only 10 product hardness is de?ned to a certain extent of the diverse applications of the novel composi by the nature of the branched-chain fatty acid tions, and as in no way imposing limitations plasticizer itself. Thus, in general, the greater thereon, there being many related and other uses the length of the branched-chain, or the more which will at once be apparent to those skilled in complex the branched nature of the fatty acid, such arts. 15 the harder the plasticized prolamine composition In practicing this invention, the optimum for any given amount of plasticizer. The pres quantities of plasticizer to be incorporated to se ence of hydroxyl or of amino groups, or of un cure the qualities desired for the use to which the saturation in the acid structure, is found to im resultant composition is to be put, will at once be prove the softening or plasticizing action and apparent to those skilled in the respective arts compatibility with the prolamine. It is evident, 20 from the further description and examples here then, that a wide range of plasticized composi inafter set forth'. tions are obtainable ‘by- means of this discovery, As a general procedure, the prolamine and and, further, that product characteristics may be plasticizer may be thoroughly mixed in the de modi?ed at will by judicious choice of plasticizer sired proportions at room temperature. The mix and the quantity thereof incorporated with the 25 ture may then be heated and maintained at a prolamine. more or less elevated temperature until homo It has previously been proposed to plasticize geneity has been attained, as evidenced by disap various proteins, including the prolamine zein, pearance of the prolamine and plasticizer as in with saturated and unsaturated straight-chain dividual entities with consequent formation of a fatty acids such as, for example, butyric acid, single, homogeneous mass. This may be carried caprylic acid, caproic acid, capric acid, stearic out in internal mixing machines or upon plastic acid, linoleic acid, oleic acid, and the like. How milling rolls. Pigments, dyes, ?llers, resins and ever these present various disadvantages, thus: the like may be added to the masses while in these the problem of offensive odor practically pre machines. Upon cooling to room temperature, cludes use of the shorter-chain acids; longer the plasticized composition will be more or less chain acids of this type are very poorly com hard and pliable, depending upon the amount and patible and exhibit negligible plasticizing activity. On the other hand, the branched-chain fatty acids of the present invention are not only ef fective prolamine plasticizers, but are character ized by practically unnoticeable, bland, mild odors. Furthermore, these branched-chain com pounds exhibit relatively high boiling points, gen erally increasing with molecular weight, and are consequently subject to very slow evaporation from the compositions in which they are incor porated. For example, of the suitable plasticizers nature of ,plasticizer incorporated therein, as hereinabove set forth. In the incorporation of other materials with plasticized prolamlne com 40 positions for the production of lacquers, sizing, coating or impregnating materials, printing inks, adhesives, or the like, it is frequently advanta geous to mix all of the individual components 45 thereof including solvents at the outset of opera tions, rather than to plasticize the prolamine pre liminarily and thereafter to incorporate the plas ticized product with the other compounding ma for the present invention, at normal pressures terials, although such may be done. However the (760 mm. of mercury), trimethyl acetic acid boils sequence of such operations is not at all critical, at a temperature of about 163.8° C. 2-ethyl 50 and'in general will be governed by the character butyric acid (2-ethyl butanoic acid) in the range of the technical operations involved, by the ar 195 to 197° C. Z-methyl propanoic acid (isobutyric rangement thereof which results in optimum 0., 2-ethy1 ca ‘acid) at a temperature of 154.4” process economies, and by the established pro proio acid (Z-ethyl hexanoic acid) in the range duction methods conventionally practiced in each 223 to 225° Gui-methyl propenoic acid (meth 55 particular industry. acrylic acid) at a temperature of 163° C., and As hereinabove set forth, the plasticizers of 2-octy1 capric acid (Z-octyl decanoic acid) boils the present invention may be employed, alone or at a temperature of 270 to 275° C. under a pres in conjunction with other known plasticizers, for sure of 100 mm. of mercury. Branched-chain various plastic modi?ed prolamine compositions, fatty acids having a total number of carbon 60 such as, for example, aldehyde reacted prolamine atoms outside of the preferred range of 4 to 18 plastics. It is well known to react prolamines inclusive hereinabove set forth are not particu with aldehydes, particularly formaldehyde, to larly well suited for plasticizing prolarnines since form solutions, coatings, and thermosetting acids of this type of greater than 18 carbon plastic compositions of improved water resistance atoms exhibit little if any plasticizing activity. Further, branched-chain fatty acid compounds within this preferred range are substantially wa ter-insoluble save for the lowest members there - of, which are soluble to a certain extent. The plasticized compositions resulting from practice of this invention have been found of ver satile utilities not only as plastic rods, sheets and molded articles, but also as coatings of various types. Thus, for example, these compositions may be made into solutions and applied as a siz and widely varying properties depending upon the nature and amount of ingredients incorpo rated therein, and upon the temperature and duration of aldehyde reaction. If_ desired, the 0 plasticized prolamine compositions of this in vention may be aldehyde-cured according to con ventional techniques, to result in useful plastics and coating compositions which, after curing, are no longer thermoplastic, but are thermosetting 75 in nature, and by reason of the plasticizers set 2,410,124 forthin the present invention are ?exible and portant practical applications thereof. It is to be explicitly understood that the. present inven tough. It is apparent that while aldehyde cur ing operations with plastics and coatings are preferably carried out upon conclusion of plasti cization of the prolamine material, it is possible to add the plasticizers to solutions of prolamines which have been ?rst reacted with the aldehydes. The prolamines constitute a large‘ portion of tion is in no way limited to the applications thereof set forth in these examples,'nor to the particular ingredients or to the amounts therein speci?ed, since equivalent ingredients in varying the protein found in the starchy or endosperm parts of the cereal grains and they are commonly 10 isolated from such starchy portions after the I grains have been de-germinated, as for example in cornstarch manufacture by the wet-milling process or in the manufacture of wheat or other ?ours by the dry-milling process. The starches may be removed by mechanical washing action 15 as in the preparation of wheat gluten, by wet 4 materials. Thus, for example, methyl Cellosolve, kneading of the ?oury mixture, or they may be aqueous ethyl alcohol, aqueous isopropyl alcohol, 20 aqueous diacetone alcohol, carbitol, methyl carbitol, are individually solvents both for zein and for the plasticizers used in this invention, and purposes functioning as auxiliary solvents of which many are known in the prolamine solvent ?eld. 30 _ Example 1 I and 30 parts of placed in a jacketed 35 0., temperature in the general 0., for a period of about 60 minutes, at which time plasticization of the 40 zein had been substantially completed vas evi~ denced by disappearance .of the zein and of considerable proportion of a prolamine. as a suitable corn protein for forming plastics we may use the corn gluten resulting from the commercial separation of cornstarch in the wet milling process, which gluten may contain from 45 40 to 65% by weight of corn proteins primarily of prolamine nature, a large part being the al starch with small quantities of cellulosic bodies 50 and fatty substances. Partially ‘puri?ed corn glutens such as those produced in Shildneck Patent U. S. No. 2,274,004 by further removal of starch with acids or as shown in Schopmeyer 55 Patent, U. S. No. 2,310,104, wherein fatty mate By weight 10 parts of Z-ethyl hexanoic acid, Q 5 parts of 2-ethyl decanoic acid, 15 parts of oleic acid, 5 parts of 2-methyl propanoic acid, and 10 rials are removed and which contain'60 to 100% - by weight of protein content, may also be used in 60 mixer to a temper ature in the general range of 120° to 135° C., while 60 parts of zein were gradually mixed in during protein is the course of an hour. used in the description here given and in the The plastic dough wash appended claims, I include by such term not further worked for a period of about 20 minutes, 65 alone the puri?ed prolamines isolated zein was substantially complete. Upon cooling a small portion to room temperature the product 70 and pliable at vordinary temperatures, and thus directly usable to a more or less limited extent, the scope of the present invention, and the presently more im as a plastic. When cooled to below 70° C., there was incorporated in the main plastic batch by 75 weight 30 parts of rosin and thereafter 1 part of ' 2,410,124 Example 5 By weight 40 parts of zein and 60 parts of trioxymethylene. The batch was then sheeted at about 70° to 80° C. on rubber rolls and pieces ' 2-ethyl hexanoic acid were dissolved at room tem perature in a solvent mixture comprised of about were then pressed in a heated press at 250 lbs. per square inch at 135° C., for one halt hour. This gave aldehyde-cured plastic articles gener ally similar to those produced by Example 1 but 30 parts by weight of methyl Cellosolve and about '70 parts by weight of 95% (by weight) ethyl a1 distinguished therefrom by not being thermo directly applicable for‘ many uses; for example, cohol. The resulting solution was found to be plastic and by having greater water-resistance. for sizing, coating, impregnating and waterproof ing textiles, paper, wood, tinplate and the like. Example 3 As a coating material, the solution was emi A rubber-like plastic suitable for use as a shoe sole was made by mixing in an internal mixer the following ingredients: nently suited for application ‘to varnished, lac quered, and the like surfaces. Furtheryit was found to form removable strong, tough, pliable, Parts by weight Zein _________________ __, ________________ ..- 3'1 2-ethyl hexanoic acid ___________________ __ 35 15 transparent films when cast upon an oiled or waxed glass surface. In addition to these proper ties, the films were oil-resistant, hard and non tacky in nature, and furnished an excellent sur Dibutyl butanoic acid _______ __' __________ __ 91/2 Trioxymethylene _______________________ __ 11/2 Clay ________ _'______' ____________________ __ face for printing purposes. 12 Carbon black ___________________________ __ When applied to 20 paper there resulted excellent grease- and mois 5 ture-proof coatings, giving ?exible wrappings The zein and plasticizer were first entered into the internal mixer and‘after working for ap proximately one hour the pigments were added suitable for food-stuff packaging. Coated upon tinplate the coating was found to withstand can, forming operations and repeated flexing without in small portions at a time more readily to pro 25 cracking. The coating was excellent in grease- ' vide a homogeneous mixture. The working of resistance. the mass readily provides heat which was removed by cooling to. below 80° C., by a water-cooled jacket upon the internal mixer. Thereafter the Example 6. By weight 20 parts of cereal gluten derived - trioxymethylene was quickly introduced and 30. from corn, 40 parts of Z-propyl butanoic acid, 10 parts of tetraethylene glycol and 25 parts of car milled in during a short period of time of five bon black were thoroughly ground together on minutes or less, at below about 80° C. The plastic a roller mill. The resultant product was found mas'swas then removed from the internal mixer to be suited for use as an ink for printing cotton and sheeted out at below about 80° C. upon a rubber milling roll and portions or the thermo 35 bags. ~ Example 7 plastic uncured sheet were then placed within an ordinary shoe sole mold such as is used in’ By weight 4'1 parts of zein, 53 parts of 2-ethyl the rubber trade. Curing was then carried out > decanoic acid, 100 parts of clay, and about 50 by heating such mold to 130° C., for one-half hour parts of 80% (by volume) aqueous ethyl alcohol under a hydraulic pressure of 100 to 500 lbs. 40 and 15 parts of ethyl lactate were thoroughly per square inch. Such pressures have been found 7 mixed together and ground in a ball mill for a suitable in the manufacture of plastics from period of about 24 hours. The resultant compo prolamines. The product was tough and flexible sitionwas knife-coated onto a sized woven sheet and in general had qualities similar to ordinary ing base, which was then force-dried'for about 1 .45 hour at a. temperature of about 150° F. The ,re- ' rubber shoe soles. Example 4 sultant “oilcloth” type of product exhibited‘ ex cellent wearing qualities, resistance to ?exing As an example wherein there is employed a and to the action of water, acids, and greases. crude mixture of cereal proteins ‘containing pro lamines, hard prolamine plastic articles such as 60 Example 8 door knobs of‘ a black color were made by mold By weight 95 parts of zein, 5 parts or 2-octyl ing under similar conditions to those used in Example 3 masses of the following plastic mix ture: ' decanoic acid, 0.1 part or oil-soluble dyestuff Yellow OB, and about ‘240 parts'of a solvent mix- . Parts by weight Corn gluten, 60% protein content ________ __ 40 55 Nevillac 10° (coumarone indenephenol resin, Neville 00., Pittsburgh, Pa.) ___________ __ 35 ture comprised of 80 parts by weight of diacetone alcohol and 160 parts by weight of 95% (by vol ume) ethyl alcohol, were mixed together over night in a ball mill. The product was a shellac substitute eminently suited for coating wooden 2-ethyl decanoic acid _____________________ -_ 10 Asbestine ___'____-_ _______________________ __ 8 Channel black ______________________ _,______ 5 Trioxymethylene ________________________ __ 2 In making the plastic mixture the plasticizer, surfaces. ' Example 9 By weight75 parts of gliadin and 25 parts of _ 2-ethyl hexanoic acid were thoroughly mixed, at resin and gluten were ?rst mixed in a plastic masticating machine. The pigments were then incorporated by adding small portions at a time and the mass worked until it was thoroughly uniform. While still in the plastic machine, the mass was then cooled to ‘75° C., and the tri oxymethylene quickly introduced. After further 70 working for approximately ?ve minutes to dis tribute the formaldehyde-curing compound uni formly throughout the mass, the mass was re moved from the mixer and sheeted at below ‘75° to 80° C., in milling rolls, prior to actual molding room temperature. The resultant mixture was heated to a temperature of about 127° C., and maintained at a temperature in the general range 120° C. to 135° C., for a period of about 35 min utes, at which time a clear, homogeneous solution indicating complete plasticization of the gliadin, had resulted. Upon cooling to room temperature a clear, transparent, substantially colorless, ther moplastic product resulted. When all of the re sulting material is dissolved at room temperature in a volatile solvent mixture comprised of about 65 parts by weight of 95% (by volume) ethanol, operations at temperatures above 120° C. !____-_ ' 2,410,124 about 20 parts by weight of glacial acetic acid, . and about 15 parts by weight of water, the result ant composition exhibited excellent properties as a quick-drying adhesive. In place of ‘the 75 parts of gliadin a similar glue may be made by substituting 75 parts of hordein. ' . 10 merous ?exings. The mixture may also be em pioyed as an interior wall paint preferably after adding per one part by weight thereof 0.5 part by weight of water; ' Example 14 Example ‘ 10 A zein dispersion in water'with ammonium ros inate was prepared according to the method of Drewsen and Little (U. S. Patent No. 2,247,531) dissolved in the plasticlzer the mixture was ap- ' 10 To 5 parts of zein by weight there was added 95 parts of 2-ethyl octanoic acid. After the zein plied to rayon yarns as a size which provided such and further to lubricate the yarns during spin ning operations. 15 - Then a stiff homogeneous mixture of am monium rosinate was prepared by thoroughly mixing for several hoursv at an elevated tempera ture not in excess of 200° F., 4 parts by weight (dry basis) of papermaker’s rosin and about 1 20 part by weight of aqua ammonia (26° Be). mix thus prepared 2 parts by weight of Z-ethyl .hexanolc acid to act as a plasticizer. This fatty‘ ‘weight of methyl Cellosolve and about 105 parts 25 acid was readily emulsi?ed into the mix. This by weight of isopropyl'alcohol. The resultant mix was then employed to clay coat paper by ?rst homogeneous product was knife-coated onto a mixing it ‘with a.clay.dispersion. A suitable clay dispersion was prepared by slurrying together by weight 400 parts of kaolin, 200 parts of water and range 170° to 180° F., for a period of about 2 30 5.5 parts of sodium pyrophosphate. To 3 parts hours. The resultant material was a dull black by weight of the clay slurry there was then added arti?cial leather which was eminently adapted to embossing operations. plasticized zein dispersion, ' Example 12 35 Twenty grams of zeinwere dissolved in 50 ml. of 95% (by volume) ethyl alcohol and 18 ml. of excellent qualities as a paper coater and gave a clay-coated paper of sat isfactory adhesion and wax-pick test. The foregoing description and commercial aqueous formalin (40% by volume), and the solution was treated in an autoclave at 15 lbs. steam pressure or 121° C., for 1 hour. 40 the solution of prolamine reaction product thus ' 1. A plastic-ized “prolamine-base” composition ?exible clear coat ings were secured, which if further heated for 3 hours at a temperature'above 130° C., became . quite water-resistant as well as grease-resistant and highly ?exible. of matter comprising alkyi branched-chain organic fatty acid in which the total number of carbon atoms in the molecule is in the range from 4 to 18 inclusive, and “proiamine-base" pro tein. . - 2. A plasticized prolamine composition of mat Example 13 ter comprising alkyl branched-chain organic fatty acid in which the total number of carbon atoms in the molecule is in the range from 4 to 18 inclusive, and zein. ‘ - . 3. A plasticized prolamine composition of mat ter comprising alkyl branched-chain organic fatty ' acid in which the total number of carbon atoms in the molecule is in the range from 4 to ,18 inclusive, and gliadin. was then introduced into this solution 15 parts a de-starched, de-oiled corn gluten 4. A plasticized prolamine composition of mat ter comprising alkyl branched-chain organic fatty I acid in which the total number of carbon atoms in the molecule is in‘ the range from.4 to 18 - inclusive, and hordein. 5. A plasticized prolamine composition of mat . ture of about 165° F. After being maintained at a temperature in the general range 160° to 170° 65 atoms in the molecule is in the range from 4 to- 18 _ F., for about 2 hours, the mixture had become a inclusive, and prola'mine-containing smooth‘ paste. This was roller-coated onto a gluten. cereal ' piece of cotton square. cloth of 80 x 80 ‘threads per inch ' 6. A plasticized “prolamine-base” composition After drying, a stiffened fabric. exhibit 70 of matter comprising alkyl branched-chain or ganic fatty acid in which the total number of car shade/cloth having appropriate stiffness and ?ex bon atoms in the molecule is in the range from 4 to 18 inclusive, and zein-base protein. > ibility for such use, and it evidenced only very 7. A plasticized prolamine composition of mat slight tendencies to crack upon aging after nu ing a black ?nish, resulted. This prepared mate- ‘ rlal was eminently suited for use as a window 75 ter consisting of prolamine and alkyl branched ' 2,410,124 11 chain organic fatty acid plasticizer therefor, in which the total number of carbon atoms in the fatty acid molecule is in the range from 4 to 18 inclusive. ' ' 8. A plastlcized prolamlne composition of mat 12 14. A composition comprising by weight at least 5 parts of “prolamine-base” protein derived from corn and from 5 to 95 parts of alkyl branched chain organic fatty acid in which the total num ber of carbon atoms in the molecule is in the ter consisting substantially of zein and alkyl range from 4 to 18 inclusive. branched-chain organic fatty acid piasticizer tion form, “prolamine-base" protein, alkyl branched-chain organic fatty acid plasticizer therefor, in which the total number of carbon atoms in the fatty acid molecule is in the range from 4 to 18 inclusive. 9. A plasticized prolamine composition of mat ter consisting substantially of gliadin and alkyl branched-chain organic fatty acid plasticizer 15. A coating composition comprising in solu therefor, in which the total number of carbon atoms in the molecule is in the range from 4 to 18 inclusive, and a mutual solvent for said mate rials. - 16. A coating composition comprising in solu therefor, in which the total number of carbon tion form "prolamine-base” protein, alkyl 15 atoms in the fatty acid molecule is in the range branched-chain fatty acid plasticizer therefor from 4 to 18 inclusive. in which the total number of carbon atoms in 10. A plasticized prolamine composition of mat the fatty acid is in the range from 4 to 18 inclu ter consisting substantially of hordein and alkyl sive, and a mutual solvent for said materials, there branched-chain organic fatty acid plasticizer being ‘by weight at least 5 parts of the said pro therefor, in which the total number of carbon 20 tein and from 5 to 95 parts of said ‘plasticizer. atoms in the fatty acid molecule is in the range 17. A coating composition comprising in solution from 4 to 18 inclusive. . m form "zein-base,” protein, alkyl branched-chain 11. A plasticized prolamine composition of mat fatty acid plasticizer therefor in which the total ter consisting substantially of prolami'ne-contain number of carbon atoms in the fatty acid is in ing cereal gluten and alkyl branched-chain or 25 the range from 4 to 18 inclusive, and a mutual ganic fatty acid plasticizer therefor, in which solvent for said materials, there being by weight the total number of carbon atoms in the fatty acid ‘ at least 5 parts of the said protein and from 5 to molecule is in the range from 4 to 18 inclusive. 95 partsv of said plasticizer. 12. A plasticized “prolamine-base” composi 18. A coating composition comprising in solu tion of matter consisting substantially of "pro 30 tion form zein, alkyl branched-chain fatty acid ‘ lamine-base” protein and alkyl branched-chain organic fatty acid plasticizer therefor, in which ' plasticizer therefor in which the total number of carbon atoms in the fatty acid is in the range from 4 to 18 inclusive, and a mutual solvent for said materials, there being by weight at least 5 13. A composition comprising by weight at 35 parts of the said zein and from 5 to 95 parts of the total number of carbon atoms in the fatty acid molecule is in the‘range from 4 to 18 inclusive. least 5‘ parts of “prolamine-base” protein and from 5 to 95 parts of alkyl branched-chain organic fatty acid in which the total number of carbon atoms in the‘ molecule is in the range from 4 to w 18 inclusive. said plasticizer. ' ' WILLARD L. MORGANJ/ '