Патент USA US2137168код для вставки
Patented Nov. 15, 1938 - 2,137,168 fiJNlTED STATES‘ PATENT OFFICE‘ , 2,137,168 ' ’ PRODUCTION I . , or SELF-SUSTAINING l ' TRANSPARENT mus Harold Alvin Lovey, New Orleans, La. ~ No Drawing. Application May 20,1986, Serial No. 80,919 K is Claims. v(c1. 91-368) will assist in bursting the granules of starch to The present invention relates to a composite self-sustaining ?lm of a high degree ofv trans-I parency made from a water-soluble carbohy drate, and, preferably, carrying on one or both 5. sides of the ?lm a waterproo?ng coating. In one form of the invention, only one side of the ?lm carries a waterproo?ng coating‘and the other side is inherently adhesive and is adapted to easily' bond itself to most surfaces, except those 10 which are waxy, greasy or oily. produce a gelatinous mass. Anyv alkali may be used as a treating agent, but it is preferred to use caustic soda. The amount of caustic soda used will vary in accordance with the desired adhesiveness of the ?nal starch hydrate ?lm, and it generally may be stated that the caustic soda may be added in an amount equal to one-half (l/z) of one per cent (1%) to four per cent (4%), based on the weight of the dry starch. Any of the‘ water-soluble carbohydrates from the starches down through most of the sugars may be used, such “amylin”, dextrines, and starch gums, the saccharides, water-soluble carbohy , , 10 Broadly, in accordance with the present inven tion, the starch, such as cassava starch, is treated so as to cause the granules of starch to swell and disintegrate, and produce a gelatinous mass, 15 \ drate gums, such as acacia or the like, pentoses, ' which clari?es into a more or less transparent ethers and esters thereof, and many polyhydric - stringy mass. Therefore, any agent may be used alcohols of relatively high molecular weight. In the more speci?c aspect of the invention, the self-sustaining ?lm is a starch derivative, or 20 stated differently, a starch .base,'as for example, starch hydrate, hydrolyzed starch, dextrinized ,25 which performs the above function. Instead of using caustic soda, potassium hydroxide, am monium hydroxide, lithium hydroxide and simi lar compounds may be used. 20 Instead of using alkalies, the amines, such as starch, water-soluble. starch esters and water soluble starch ethers. Starch acetate,'starch ni rate and starch xanthate, are examples of wate di-methyl amine and related homologs of this series may be used. Instead of using caustic alkalies, other alkalies may be used, such as oluble starch esters. ' sodium carbonate. Basic salts and readily It has heretofore been proposed to make self- Y hydrolyzable salts of weak acids may also be ustaining starch ?lms, as pointed out in my. used. Generally stated, the starch solution or prior Patent No. 2,012,344, granted ‘August 27, any_water-soluble carbohydrate may be mixed 1935. Broadly, the methods therein set forth 30 may be utilized for the preparation of the pres with water, or any material which will perform the same function as water, and a small amount ent ?lms.v , - of acid, base, salt, catalyst, enzymatic substance, . In accordance with the present invention, the .or any material which will break down the transparency and/or clarity and/ ?exibility of starch or water-soluble carbohydrate material the water soluble carbohydrate, and especially into a more or less transparent mass. . 35 starch ?lms, is greatly improved, and its tend The amount of alkali or equivalent agents used ency to disintegrate and/or decay .is greatly in—. will determine the adhesiveness of the starch , hibited and reduced to a minimum. hydrate ?lm. Using alkalies other‘ than caustic The present invention will be illustrated by the soda, or other treatment agents, so much thereof preparation of a starch ?lm, but it is to un ‘will be added which will produce a pH‘ or alkalin-' 40 derstood that the procedure herein-set forth is applicable to thetreatment of all solublecarbo hydrates which will form self-sustaining fairly ity in the cooking operation equivalent to that I produced by the caustic soda in the amount speci?ed. ‘ transparent ?lms from a solution,‘ preferably an aqueous solution. Any of the available starches may be used for the alkali is heated, preferably, in a water jacket with continued stirring to about 160° F; This is preparing the ?lm, although preference is given the preferred temperature in the case of cassava to the root starches rather than to the cereal starches. Examples of suitable starches are will be different. those derived from corn, potato, arrow-root, rice, 0 cassava, or the like, The use’ of cassava starch is highly desirable, as this produces the toughest and strongest self-sustaining ?lms.v . ' Utilizing cassava starch, the latter is mixed with about six (6) to ten (10) times its weight 55 of water, to which may be added an alkali which The starch mass which has been treated with starch. For other starches, the temperatures . The time that the starch is treated with the ‘ disintegrating agent ‘will, of course, vary with the character of the starch and the character of the disintegrating agent. An additional factor in?uencing the time of treatment is the size and shape of the treatment container. In the above speci?c example, the cooking of the cassava ‘ 2 2,137,168 starch is carried out in a one gallon cylindrical (15%) of the protein adhesive increasing agents vessel, whose diameter and height are preferably the same. The time of cooking is about twenty (20) minutes to one-half hour, after the starch reaches the temperature of about 165° F. This temperature, is, preferably, although not neces sarily, maintained approximately constant dur may be introduced into the mass. To the plastic solution either with or without the adhesive-increasing agent, there is added a ing the cooking operation. suitable plasticizing agent in amounts equivalent to ?fteen per cent (15%) to forty per cent (40%) of the weight of the dry starch. The plasticizing agent may be a glycerol or a glycol, as for exam The excess alkali present in the starch solution 10 is preferably neutralized with any suitable neu ple, ethylene glycol, propylene glycol, di-ethylene tralizing agent, but preferably with phosphoric glycol and similar polyhydric alcohols, as well as 10 the various sugars including the mono-, di- and acid, using phenol phthalein as an indicator. tri-sacchroses, the pentoses and pentosan gums. Nearly all of the inorganic acids and organic Practically all of the carbohydrates have a If the carbohydrate is substantially hygroscopic, its 15 acids are the chemical equivalents of phosphoric , de?nite plasticizing value for the starch ?lm. 16 acid as a neutralizing agent. except those acids which have an oxidizing effect, such as nitric effectiveness as a. plasticizing agent is correspond acid, chloric acid, per chloric acid, chromic acid, ingly greater than those carbohydrates which and similar compounds. Phosphoric acid is pre ferred, since it appears to produce a plastic with the fact that only a few per cent of the neu are less hygroscopic. As illustrative of the mono-sacchroses, refer ence is made to glucose and fructose. v20 As representatives of the di-sacchroses, refer tralizing agent is necessary, sulphuric, hydro ence is made to sucrose and maltose. better ?owing properties. However, in view of chloric, acetic and oxalic acids may well be used. A ?lm produced from the above mass is in herently adhesive because the starch has been cooked- under alkaline conditions. In other words, an alkaline cook produces an adhesive ?lm, the adhesive qualities of which vary with in limits in accordance with the amount of al kali produced. . . Under some conditions, it may be desirable to produce a ?lm which does not possess an ad hesive surface to produce a starch hydrate ?lm or a water soluble carbohydrate ?lm which does not have an adhesive surface, and in order to do so it is merely necessary to cook the starch under neutral or non-alkaline_condition, that is, main tain a pH as near 7 as possible. In all events, it is important to avoid an alkali cook when it is desired to produce a ?lm with a non-adhesive surface. . Those ?lms which have little or no adhesive properties may have the adhesive properties in tensi?ed by incorporating in the ?lm an adhesive 45 agent. Any agent which will mix well with a starch hydrate solution and become an integral soluble part thereof may be incorporated in any suitable manner in the starch mass. Similarly, any water-soluble carbohydrate‘ which is not in 50 herently‘adhesive, may have its adhesive quali ties increased by adding thereto an adhesive in creasing agent. Examples of‘ suitable adhesives are dextrine carbohydrate gums, such as arable, tragacanth, karaya, gum ghatti, irish moss, 05 quince seed, and locust bean, as well as glue, gel atin, casein, alginic compounds, including al ‘ ginates, and blood and egg albumen; Where it is desirable to increase the adhesive As representatives of the tri-sacchroses, refer ence is made to mellitose and railinose. Zylose and arabonose are representatives of the pentoses, and mannan and araben are repre sentative of the pentosan gums. In addition, various natural gums above re ferred to, and which contain substantial amounts of the’ pentosan gums are very well suited for this work. These natural gums are gum traga canth, arabic, karaya, and- the like. In the preferred form of the invention, it is desirable to add to the plastic solution a pre servative medium to inhibit organic disintegra tion and decay of the starch ?lm. Any material may be used, either organic or inorganic, which will so function. Examples thereof are borax, sodium benzoate, sodium salicylate, sodium or thophenyl-phenate, beta-naphthol and the like. 40 These compounds are set forth by way of exam ple, and not limitation. The amount of pre servative added will depend on a number of fac tors including the character of the starch and the kind of preservative agent used. However, when 45 using borax in an amount equal to four per cent (4%) of the weight of the dry starch gives sat isfactory results. When using sodium-ortho phenyl-phenate, it is desirable to add one-thirti eth (1/30) of one percent (1%) based on the 60 weight of the dry starch. Any preservative which will inhibit the decay of organic matter, retard the growth of mold, fungi, bacteria and protozoa will maintain the utility and value of the starch ?lm. Most all ‘of the inorganic salts possess varying degrees of e?ectivenessin this role, and most of the aro matic organic compounds may be introduced into the starch‘ hydrate mass as a water solution, or if these or any other compounds are not soluble ingredient may be added in various amounts, gen- ' qualities of the starch hydrate ?lm, the adhesive so in water, soluble'derivatives may be formed and erally in amounts around ten per cent (10%). -these introduced into the mass. For example, Broadly, however, it may be stated that the ad the' aromatic hydrocarbons and their derivatives hesive increasing agent may be introduced into may be sulphonated, or some other treatment ef the plastic mass in amounts varying from ten per fected to bring the insoluble compound into the 65 cent (10%) to ninety per cent (90%) of the ul soluble form. Further, the insoluble compounds timate weight of the ?lm. When the protein may be introduced in the form of an emulsion. products, such as gelatin, casein, albumen and Additional examples of the preservatives are the the like are introduced into the starch hydrate water soluble inorganic salts. of such metals as copper, arsenic, mercury, thalium, antimony, and 70 70 ?lm, the amount should not exceed approxi mately about ?fteen per cent (15%) based on the like. Other effective organic agents inhibit the dry weight of the starch, since around this ing decay arev substantially all of the aromatic percentage the transparency of the resulting ?lm alcohols and all of the turpene alcohols, of which is substantially reduced, and borders on trans cresol, resorcinol, thymol, are representative, and 76 lucency. Any amount below ?fteen per cent are mentioned merely as representative of the 75 3 2,187,168 aromatic alcohols; and pineol and borneol, which equal to about ten per cent (10%), based on th are representative of the turpene alcohols and are mentioned merely as representative of the weight of the dry starch. _. Y ‘The starch ?lm may be produced as above set turpene alcohols. , ‘forth and preferably includes an adhesive in-‘ In general, it may be stated that the amount creasing agent, a plasticizing agent, a preserva vof preservative agent will vary in accordance tive agent and a clarifying agent. In some cases, with the toxicity of the preservative agent, and any or all of these various agents may be omitted, somewhat in accordance with the character of but in order to produce a high class commercial the material treated, that is, whether the basic article, it is preferred to proceed to improve the material is starch, a starch nitrate, a starch ace-‘ quality of the ?lm by the treatment above set 10 tate or some other water soluble carbohydrate. In the case of highly toxic materials, amounts , forth. ' ’ will be necessary, and as much as up to four‘ per The starch plastic, including ‘any or all of the i above additive agents, is spread into ?lm form. This may be done by providing a clean polished surface of metal, such as nickel, stainless steels, 16 aluminum and the like or non-metallic surfaces, such as polished Bakelite, glass, rubber and equiv cent (4%) may be desirable to inhibit decay in alent surfaces. varying from about one-thirtieth (1,450) to one ?fth (1A,) of one per cent (1%) based on the 15 weight of the dry ?lm, will inhibit decay, while for the less active agents, such as borax,jmore - - Any smooth polished surfaces‘ of the character It has been discovered that transparency and above set forth may be coated with a thin ?lm 20 clarity of the ?lm, and particularly starch ?lms, . of wax, such as carnauba wax, candeiim-paramn, may be substantially improved by the. addition and the like, or instead of using wax, oils mayv of a clarifying'agent to the plastic mass. Suit be used, such as cotton seed oil, corn oil, oleo able clarifying agents are the amino compounds. stearene, etc. The starch plastlc'is extruded or In general, it may be stated that the substituted poured on this surface and gauged down to the 25' ammonias, and their addition products, are suit desired thickness by a doctor blade or scraper able. Included in this generic term are the which moves over strips ofv vsuch thickness as a warm humid atmosphere. , , amines, amides, imides, anilines, anilides, the will produce an ultimately dried ?lm of the de-_ cyclic nitrogen compounds, such " as pyridine, sired dimensions. The dried ?lm may'range in quinoline, acridine and the-like, as. well as the‘ thickness fromabout 0.0005 to 0,008 depending hydrazines, hydroxyl amines and the oximes. on whether’it is used as a wrapping ‘or packag It may be stated that the more alkaline the ing sheet, or whether it ‘is used as an adhesive amine, the less the amount required. However, material, as hereinafter more fully pointed out. there appears to be other aspects to' the clarify The carrier surface and the thin ?lm starch" ing of the plastic than the alkalinity alone. Ex is dried in an'oven at about 160° to 185° for periments indicate that the amines have the about ten (10) minutes. If lower-temperatures capacity of digesting and dispersing the shells are used for drying, the~~drying~ period is corre spondingly longer. _ of the starch granules which appear to be a form may vary greatly, so The longtemperature as the temperature of drying‘ is, of hemi-cellulose, and thereby eliminate the not su?icient‘to burn or damage the ?lm. 1 40 ‘slight cloudiness which results from their pres ence. Alkalinity alone does not produce this‘ It may be stated that the time of drying varies result. with the thickness of the ?lm, the temperature The amount of clarifying agent added de- _ and the relative humidity of the drying air,_tli'e velocity with which the air passes .over the dry particular amino compound used. Using the ing sheet, the amount of water evaporated from amines, satisfactory results are obtained by add the sheet, ‘and the tendency of the starch hydrate pends on the character of the starch and the ing from one per cent (1%) to ten per cent ?lm to oxide or skin over. The time of drying . ‘(10%) of the weight of the dry starch. When -may vary from two and three-fourths (23/4) min-g ' using tetra substitutedamines (such as tetrone utes to more than an hour. The'optimum' cori-~ B) and treating‘ cassava starch, one percent ditions for a ?lm .of one-thousandth (M000) ofv (1%) of this quaternary substituted amine, based an inch thick are a moisture content of eighty on the weight of the dry starch, is used. ' per cent (80%), axtemperature of about 185° F. When using tri-ethanol amine and treating‘ dry bulb, and 135° F. wet bulb, and an air veloc cassava starch, ten per cent (10%) of this amine, ity of about 300 linear feet ‘per minute. These based on the weight of the starch is used. Amino ‘derivatives, such as the acct-amines, as 4 conditions will prevent skinning over of a nor‘mal starch cook. _ for example, acet-amide, acet-anilide, and the ' The?lm, after drying, is stripped from the like, as well as the alcohol amines, such as mono-, spreading surface when the moisture content has been reduced su?lciently to produce a fairly dry ?lm. As an example, it has been found that the di- and-tri-ethanol-amine. ' The ethanol amines have the dual function of both clarifying and plasticizing the dried ?lm and may replace some ?lm is satisfactorily dried when it has had its moisture-content reduced so that the moisture content varies from twelve (12) to twenty (20) per cent of, the weight of the‘= dried starch com of the glycerol aboverefer'red to as a suitable plasticizer for the starch ?lm. Tetrone B marketed by _ ~ ‘and Haas of Philadelphia is a quaternary or tetra substituted , . ' - position ?lm. - ‘ ammonium with alkyl groups and with a molec The removal of the film from the carrier sur ular weight of-approximately 1'70. This product face is effected by picking the ?lm from the is so active in its solvent power that it dissolves ' spreading carrier surface, and then winding the > 70 cellulose present in the starch, and as a result v ?lm upon a roll of from about one-quarter ('A) 70 it is only necessary to add about one per cent of an inch to several inches in diameter, de (1%) to obtain the desired result. On the other pending upon the type of device used and the hand, less‘ active amino compounds must be rate of removal. added in greater quantities, for example, if suc The ?lm should be promptly unwound‘where cinamide is used, it should be added in an amount short spreading is made, and if the operation 4 2,187,168 is continuous, the ?lm should pass only partly around the roll onto the other equipment for the subsequent operations. The ?lm produced as above set forth may have ‘ one or both of its surfaces coated to render either both surfaces of the ?lm waterproof, or only one surface waterproof, leaving the other surface uncoated so as to take advantage-of the adhesive character of the surface and adapt the 10 ?lm to such uses as hereinafter set forth. It is within the province of the present in vention to coat the ?lm in any manner, includ ing the method set forth in my prior Patent No. 2,012,344. , When coating only one face of the ?lm, the coated composition may be applied prior to re moval of the starch ?lm from its carrier surface, and the application may be by means of a spray gun, by a brush, or the composition may be ?owed 20 on or printed on the surface by means of a suit able printing roll. _ .The waterproofed coating composition may be applied to the carrier surface and the composi tion dried to remove the volatile solvents. The starch plastic is then spread over this surface, drying the starch ?lm as above described. Thereafter, the starch ?lm carrying the water proo?ng coating which is in effect a lamination sheet comprising the starch ?lm and the water 30 proo?ng ?lm thereon may be lifted from the carrier surface. The material may then. be wound upon rolls, which are trimmed to the de sired width by means of suitable cutting knives already in use for this general type of produc 35 ‘tion._ These rolls may then be cut into smaller widths while coiled or the rolls may be unwound and passed between slitting wheels or slitting knives and subsequently wound in coils to pro vide an adhesive tape of the desired width and diameter. The ?lm may be supplied in large stock-size sheets of standard dimensions, or in suitable smaller cut-to-size dimensions. In stacking these sheets, which have only one side coated or waterproofed and the other side of an adhesive character, it is obviously necessary to avoid two starch surfaces coming in contact with each other, as the adhesive nature of this ma . terial will prevent subsequent separation with out destruction of the composite ?lm. 60 The waterproo?ng composition itself may be any of the materials set forth in my prior patent. However, in general the waterproo?ng lamina tion may consist of a coating resulting from ap plying to the starch ?lm solutions of the cellu lose esters, of which the cellulose acetates, the nitrates and benzoates are typical examples; cel lulose ethers in general, of which cellulose . Per cent Carbon 15 Hydrogen 2.5 ‘Sulphur _________________ -1 ___________ -- 82 One surface of the starch ?lm may be rendered waterproof and non-adhesive by coating the same with a thin, ?lm derived from natural and synthetic waxes which may be applied from 10 either a solution of the same, or by application in the molten state of the wax. - These coating compositions are plastlcized with suitable soften ing agents to make the resulting waterproo?ng ?lm on the starch su?iciently ?exible and plastic 15 so that the ?nal starch ?lm carrying the water proo?ng composition may be used for any of the herein described purposes. It is desired to point out that one of the fea tures of the present invention is the provision of a self-sustaining starch ?lm made of a starch 'or a starch derivative, one surface of the ?lm having a waterproofed protective coating. and the other surface being characterized by ad hesive qualities enabling the ?lm to be used for any purpose where this adhesive charactermay be taken advantage of. . - The following are representatives of suitable waterproo?ng compositions: . 1. Cellulose Ethyl Per cent nitrate _____________________ __ 15 acetate ________ _.'. _____________ _~__ Butyl 5 acetate ____________ -.' ______ __'____ 20 - Benzol ______________________________ __ 12 Methanol ____________________________ __ 8 those speci?cally hereinbefore mentioned. Per cent 40 3. Natural resins ________________________ __ Butyl acetate ________________________ __ 25 40 Acetone _____________________________ __ 15 Benzol _____________ __‘ _______________ __ 12 Methanol ________________________ __'____ 8 .45 The solvent mixture of the above set forth com position may be modi?ed to meet the requirey ' ments of the various types of natural resins in order to produce a clear transparent ?lm. It will also serve for most of the synthetic resins. ~ Per cent 4. Rubber solutions (solids) _____________ __ 10 Ethylene dichloride ___________________ __ 90 Other solvents such as carbon bi-sulphide, 55 solutions of natural resins such as dammars, coating composition. chlorinated rubbers, rubber hydrochloride, syn thetic rubber solutions, such as thiokol. Thiokol is prepared by the polymerization of chlorinated ole?ns with polysul?des. In the pre 70 ferred form ethylene di-chloride is heated at around its boiling point with sodium polysul?de (Na2s4), in which it is used in the proportion of about two and one-half (21/2) times the amount of ethylene di-chloride. The reaction is com pleted in about six (6) hours. 35 2. In the above composition, the cellulose nitrate may be substituted by a cellulose ether, including methyl ethyl, and benzyl ethers are- examples; 65 may be derived from rubber solutions made from 30 40 Dibutyl phthalate _____________________ __ acetone, solvent naphtha, etc. may be used in place of the above depending upon the _par ticular form of rubber used in formulating the kauris, copals and the like; synthetic resins in general of which the phenol aldehydes, the glyc eryl phthalates, the cumars, the vinyl esters and the like are examples. The waterproo?ng coating 13 The combusion analysis of thiokol is - Per cent 5.. Waxes ________ __,___________________ __ 6-10 Solvents ___________________________ __ 94-90 The solvents or solvent mixtures will depend upon the particular wax used. For para?in, 65 solvent naphtha may be used; for halowaxes or chlorinated naphthalenes, ethylene dichloride may be used; for true waxes such as spermacetl, carnauba and the like varying mixtures of ace tone, ethyl acetate and the like may be used. 70 It may be stated, in general, that the pre ferred waterproo?ng composition consists of those compositions containing nitrocelluloses such as cellulose nitrate. Of course, the com position is dissolved in'a suitable solvent and a 75 15' 2,187,16Q nominal amount of plasticizer is added. It may leave no free adhesive surface then the material be desirable, in some cases, to add a small amount may also be used ingeneral for wrapping or for of wax-like substances to improve the .water . any purpose for which it is desirable to provide proofness of the dried coating. For example, the a' transparent substantially waterproof ?exible base of the waterproo?ng composition may be composite sheet. . cellulose nitrate together with a small proportion One of the important products of the present of wax or natural resins together with a small invention is a clear transparent non-decayable proportion of wax or rubber solution, together vstarch ?lm which carries a waterproo?ng coat with a small proportion of wax. The use of the ing on one face and is relatively dry on the waxes while quite desirable in the nitro-cellulose other face, said dry face becoming adhesive only 10 containing compositions is not quite so desirable when moistened. Such a sheet may be used as in other waterproo?ng compositions. It is de-* a mending tape and may be sold in the usual sired to point out that in one form of the present ‘ spool form. It may also be used as a protective invention, it is desirable to use. the ‘same plasti covering for books, maps, drawings and prints, 15 cizer for the starch ?lm as is used for the water the adhesive aids of the ?lm being, of course, 15 proo?ng composition. .For example, di-ethylene applied to the objects. glycol may be used to plasticize the starch ?lm and the ultra-cellulose coating composition. It The ?lm ‘may also be applied to colored litho graphed and printing matter, and it may be may be stated that when both the starch ?lm stated that it has been impossible to put a water proof lacquer coating on such materials because 20 and the coating composition contain the same plasticizing agent, that this plasticizing agent which is common to each lamination of the ?lm tends to improve the bond between the two dis similar‘ laminations. Instead of using di-ethyl 25 ene glycol as a plasticizerpfor, both the starch ?lm and the coating composition, ethylene-gly ' col-mono-methyl-ether may be used. ' While it has been stated that a ‘common plas ticizer may be used in a starch ?lm lamina ' such a material causes the inks to‘ run. This disadvantage is entirely eliminated in accordance with ‘the use of .the product herein disclosed. a The hereindescribed laminated sheet is also suitable as a-decalcomania or a transfer, as well 25 as for ornamental decorations for, glass. It may be used in connection with transparent signs. Advertising‘. novelties, oil and water paintings and photographs may be protected and covered a 80 tion and in the waterproo?ng lamination, it is by this type of sheet. within the province of the present inventionto The herein-disclosed self-sustaining starch, use di?erent plasticizers in these two laminations ?lm is adapted for use in the pharmaceutical and use a' separate bonding agent between the . ?eld. The material may be used'as an adhesive starch ?lm lamination and the waterproo?ng tape for bandage closures and wound coverings, lamination and di-ethylene glycol and ethylene; and also as a medicated tape and as a surgical 35 glycol-mono-methyl-ether may be used as bond ing agents. ' > " ' If plasticizers are already present in the starch ?lm composition and in the waterproo?ng com position, then about 10% of the above com-. pounds, based on the weight of the starch ?lm, ,may be used to improve the, bonding of the two laminations. ‘ On the other hand, if the above substances or their substantial equivalents are to be used in the starch ?lm as a plasticizer and a bonding age'nt,.then it is preferred to have present in the starch ?lm an amount equal _to about thirty per cent (30%) of the weight of the starch. As previously pointed out, the present inven tion contemplates the provision of a self-sus taining starch ?lm which has been impregnated with or coated with a waterproo?ng material so as to coat'one or both sides of the starch ?lm. If both sides of the starch ?lm are coated, then, of course, it is not necessary to prepare the starch ?lm so that it, has adhesive qualities. However, if only one face of the starch ?lm is coated, then it is necessary to proceed-as here- ' dressing tissue, said subject matter being claimed in applicant's co-pending application Serial Number 84,563, ?led June 10, 1936. In general, it may be stated that when the self sustaining starch ?lm carrying a waterproofing coating is used as a wrapping material and is not provided with an adhesive surface, that it should vary in thickness between 0.001 and 0.0001. When the ?lm is provided with an adhesive sur face, the thickness, in general, should range from we about 0.001 to 0.003, as the case may require. This is the preferred thickness when the material is used for mending purposes. ' It may be pointed out that the ?lm of the adhesive surface may be used for bonding and 50 sealing purposes by moistening the potentially adhesive surface or the surface need not be ‘moistened. In this case, the ?lm will act as a bonded and adhesive medium. by the simple expedient of applying heat'or heat and pressure. 55 In certain cases, when the adhesive surface is moistened, the seal maybe made more e?ective by applying heat and pressure. ' , It may be stated that in the broad aspect of the present invention, all water soluble carbo co hydrates may be formed into self-sustaining in set forth to digest the starch with su?lcient alkali to produce a starch ?lm, which has in herent adhesive properties. Of course, if the transparent ?lms, the water-soluble cellulose ?lm is to be coated on both sides. then it is -esters and cellulose ethers may also be used to not necessary to incorporate any adhesive-in prepare self-sustaining transparent ?lms and the creasing agent. 65 water-soluble esters andcarbohydrates, ethers, may be includingthece'llur; treated as herein "j If the starch ?lm is not inherently adhesive, .lose it may still bevcoated on only one side and used set forth to produce composite waterproof ?lms. for many Purposes. ' ' In- general,‘ it may be stated thatthe water In general, it may be stated that the starch soluble carbohydrates are dissolved in a sum cient amount of water to obtain a viscose plastic 70v 70 ?lm if made from a non-adhesive starch com .position and ‘coated on one or both sides, but solution or colloid and extrude the same through . preferably on both sides, may be used as a trans alslot or other known type of ?lm-forming device " parent waterproof wrapping for many products. ' onto a carrier surface upon which it is dried If the ?lm is made from an adhesive starch 75 ?lm and is waterproofed on both sides so as to and subsequently removed. In the case of starch, only, it is necessary to cook the same to render 75 6 2,187,168 the starch water soluble and thereby produce a common non-volatile solvent present in both ?lms - workable plastic mass from which the ?lms are and acting as a plasticizer for both ?lms. 9. A new article of manufacture comprising a formed. . It is within the province of the present inven transparent ?exible self-sustaining inherently tion to use mixtures of different starch bases to adhesive carbohydrate ?lm formed. of a member of the group consisting of starch derivatives, sac charides, starch gums, carbohydrate gums, pen toses, ethers and esters thereof, the ?lm having present an agentinhibiting organic disintegra provide the self-sustaining starch base ?lm. For example, the starch hydrate base may be mixed with starch nitrate to provide a ?lm which has inherent adhesive properties or which does not Similarly, dex tion of the ?lm, said agent being compatible with 10 trinized starch may be mixed with starch acetate the carbohydrate ?lm and incapable of substan or starch nitrate. Any of these mixtures may be , tially reducing the transparency of the ?lm, one treated in accordance with the present invention face of said ?lm having adhesive properties, and as herein disclosed. . the other face carrying a waterproo?ng ?lm, said What is claimed is: ?lms being bonded together by a common non 15 1. A new article of manufacture consisting of volatile solvent present in both ?lms and acting ll) have any adhesive properties. a transparent ?exible self-sustaining‘ inherently adhesive starch base ?lm, adapted as a protective covering for a book and the .like, one face of said 20 ?lm having adhesive properties, said face being capable of being moistened, and the other face of which carries a waterproo?ng ?lm. 2. A new article of manufacture consisting of a transparent ?exible self-sustaining starch base ?lm possessing substantially no inherent adhesive properties but made adhesive by having incorpo rated there'in an adhesive material. ,3. A new article of manufacture consisting of a transparent ?exible self-sustaining starch base 30 ?lm possessing substantially no inherent ad hesive properties but made adhesive by having incorporated therein an adhesive material, one face only of said ?lm carrying a waterproo?ng agent, and the other face being adhesive in 35 character. - 4. A new article of manufacture consisting of a transparent ?exible self-sustaining inherently adhesive starch base ?lm, having present an agent inhibiting organic disintegration said agent be 40 ing compatible with the starch base ?lm and incapable of substantially reducing the trans parency thereof, one face of said ?lm having adhesive properties and the other face carrying a waterproo?ng ?lm, the latter being bonded to 45 the starch ?lm by a common-non-volatile solvent present in both ?lms and acting as a plasticizer for both ?lms. 5. A new article of manufacture consisting of as a plasticizer for both ?lms. 10. A new article-of manufacture comprising a transparent ?exible self-sustaining inherently adhesive starch base ?lm having present an 20 agent inhibiting organic disintegration of the ?lm, said agent being compatible with and in capable of substantially reducing the trans parency of the starch base ?lm, one face of said ?lm having adhesive properties, and .the other face carrying a water-proo?ng. ?lm, said ?lms being bonded together by a common non-volatile solvent present in‘ both ?lms and acting as a plasticizer for both ?lms. _ ‘ 11. A new article of manufacture comprising a transparent ?exible self-sustaining inherently adhesive starch base ?lm clari?ed by the pres ence of the reaction product of the starch and a clarifying agent of the substituted ammonia type capable of digesting and dispersing the shells of the starch base, one face of said ?hn having adhesive properties and the other face carrying a waterproof ?lm, said ?lms being bonded to gether by a common non-volatile solvent present in both ?lms and acting as a plasticizer for both ?lms. 12. A new article of manufacture comprising - a transparent ?exible‘ self-sustaining inherently adhesive starchvbase ?lm clari?ed by the pres- , ence of the reaction product of ‘the starch and a. clarifying agent selected from the group con sisting of amines, amides, imides, anilines, ani lides, the- cyclic nitrogen compounds including a transparent ?exible self-sustaining starch base pyridine, quinoline, acridine, hydrazine, the hy 50 ?lm containing a plasticizer and clari?ed by the droxyl amines and the oximes, and having incor porated' therein an agent inhibiting organic dis presence of a reaction product of the starch with a clarifying agent of the substituted ammonia type capable of digesting and dispersing the starch shells of the starch. 6. A new article of manufacture consisting of a transparent ?exible self-sustaining starch base ?lm containing a plasticizer and clari?ed by the presence of a reaction product of the starch with a clarifying agent of the substituted ammonia 60 type capable of digesting and dispersing the shells integration of said starch base ?lm, said agent , being compatible with and incapable of substan tially reducing the transparency of the starch base ?lm, one face of said ?lm having adhesive 55 properties and the other face carrying a water proo?ng ?lm, said ?lms being bonded together by a common non-volative solvent present in both ?lms and acting as a 'plasticizer for both ?lms. of the starch, one face of said ?lm being ad 13. The process of producing ‘a transparent hesive in character and the other face of said 1 ?exible self-sustaining carbohydrate ?lm com? ?lm carrying a waterproo?ng ?lm. 7. A new article of manufacture consisting of prising cooking a water soluble carbohydrate in an alkaline medium adapted to confer adhesive 65 65 a transparent ?exible self-sustaining carbohy drate ?lm formed of a member of the group con- ' properties upon the resulting plastic and ?lmv sisting of starch derivatives, saccharides, starch produced therefrom adding after coolnn'g a plas gums-carbohydrate gums, pentoses, ethers and ticizer, and a. clarifying agent selected from the esters thereof, one face of which has adhesive group consisting of amines, amides, imides, ani. 70 properties, and the other face of which carries a lines, anilides, the cyclic nitrogen compounds in 70 waterproo?ng ?lm. 8. A new article of manufacture consisting of a transparent ?exible self-sustaining starch ?lm, one face of which carries a waterproo?ng ?lm 76 the latter being bonded to the starch ?lm by a cluding pyridine, quinoline, acridine, hydrazine the hydroxyl amines and the oximes, casting the cooked plastic material in the form of a self sustaining ?lm, and applying to one of‘ the ad hesive surfaces of the ?lm a waterproo?ng agent. 75 7 2,187, 188 14. The process of producing a transparent ?exible self-sustaining starch ?lm comprising cooking the starch material in'an alkaline medi ‘um to confer adhesive properties upon the starch plastic and ?lm produced therefrom adding after cooking a plasticizer, and a clarifying agent se lected from the group consisting of amines, am 17. The process of producing a transparent ?exible self-sustaining starch ?lm comprising cooking the starch material to a plastic mass in an alkaline medium adapted to confer adhesive properties upon the starch plastic and the ?lm produced therefrom, adding after cooking a com pound of the substituted ammonia class to the plastic to clarify the same, said substituted am ‘ compounds including pyridine, quinoline, acridine, monia product also acting as a plasticizer for the 10 hydrazine, the hydroxyl amines and the oximes, starch ?lm, casting the cooked plastic into self casting the cooked starch plastic in the form of a sustaining ?lm, and applying to one of the ad self-sustaining ?lm, and applying‘ to one of the - hesive surfaces of the ?lm a waterproo?ng agent.‘ adhesive surfaces of the ?lm a waterproo?ng 18. The process of producing a transparent agent. ?exible self-sustaining starch ?hn comprising 15 15. The process of producing a. transparent cooking the starch material to a plastic mass in 15 ?exible self-sustaining starch ?lm comprising an alkaline medium adapted to confer adhesive . cooking the starch material to a plastic mass in properties upon the starch plastic and the ?lm a medium of sumcient alkalinity to confer ad produced therefrom, adding an ethanol amine to hesive properties upon the starch plastic and the clarify and plasticize the starch plastic, casting ?lm produced therefrom, adding after cooking a the cooked plastic into self-sustaining ?lm and plasticizer and a compound of the substituted applying to one of the'adhesive surfaces of‘the ides, imides, anilines, anilides, the cyclic nitrogen _ ammonia class to the plastic to clarify the same; ?lm a waterproo?ng agent. casting the cooked plastic in self-sustaining ?lm form and applying to one of the adhesive sur faces of the ?lm a waterproo?ng agent. » 19. The process of producing a transparent ?exible self-sustaining ‘starch ?lm comprising cooking the starch material having present gran 16. The process of producing a transparent ' ules of starch and granular shells in an alkaline ?exible self-sustaining starch ?lm comprising -medium adapted to confer adhesive properties cooking the starch material to a plastic mass in upon the starch plastic, adding to the plastic after cooking a plasticizer and‘ a substituted am a medium of sufficient alkalinity to confer ad hesive properties upon the starch plastic and the monia compound having the capacity of digest ing and dispersing the shells of the starch gran ?lm produced therefrom, adding after cooking a ules to thereby eliminate in the plastic and in the plasticizer and about 1% to 10% by weight of ?nal ?lm the slight cloudiness resulting from the the starch of a compoundof the substituted am presence of said granules, casting the so-treated monia class to the plastic to clarify the same, starch plastic into self-sustaining ?lm and ap 35 casting the cooked plastic into self-sustaining plying to one of the adhesive surfaces ‘of the ?lm ?lm and applying to one of the adhesive, sur a waterproo?ng agent. ~ faces of the ?lm a waterproo?ng agent. HAROLD ALVIN LEVEY.