US3409026A

US3409026A - Method of preparing a reconstituted tobacco composition

Info

Publication number: US3409026A
Application number: US636567A
Authority: US
Inventors: John D Hind; Robert B Seligman
Original assignee: Philip Morris USA Inc
Current assignee: Philip Morris USA Inc
Priority date: 1967-04-24
Filing date: 1967-04-24
Publication date: 1968-11-05
Anticipated expiration: 1985-11-05

Description

Un ted St ir ate i Q i i No Drawing. Application June 16, 1966, Ser. No. 557,903,

now Patent No. 3,353,541, dated Nov. 21, 1967, which 3,409,026 Patented Nov. 5, 1968 ice scribes, 'a's "binders an i'recpnstituted tobacdd, variou s water soluble polysaccharides,'such as'al'ginic and -p 'ectinic acids and their sodiumland potassium salts; derived from plantsother than'ft'obacco; for "example" derived j from is a continuation-in-part of application Ser. No. 336,009,

Jan. 6, 1964. Divided and this application Apr. 24, 1967, SerrNo. 636,567 v 1 Claim. ('Cl. 131140) ABSTRACT OF THE DISCLOSURE stituted tobacco. The binder for said reconstituted tobacco is made from tobacco plant parts and the process involves Y 1 the use of the naturally occurring tobacco pectins as said binder, which are obtained by a process in which an alkali metal carbonate is employed to treat the tobacco plant parts. The treatment involves the destruction of the alkaline earth metal cross-links of the tobacco pectins, the t release of. the resulting tobacco pectins by a washing action and finally the shaping of the resultant slurry into a tobacco product.

This application is a division of application Ser. No. 557,903 filed June 16, 1966, now Patent No. 3,353,541, which in turn was a continuation-in-part of application, Ser. No. 336,009, which was filed on Jan. 6, 1964, now abandoned, and which, in turn, is a continuation-in-partof application, Ser. No. 240,130 filed Nov. 26, 1962, now abandoned, and application, Ser. No. 169,995 filed Jan; 16, 1962, now abandoned.

This invention relates generally to methods ofproducing reconstituted tobacco compositions. More particularly, this invention relates to methods for the productionof novel tobacco compositions utilizing self contained pectins as adhesives therefor. Y

During the production and processing of tobacco products, including aging, blending, sheetforming, cutting, drying, cooling, screening, shaping and packaging, considerable amounts of tobacco fines and tobacco dust are produced. It is known that such tobacco fines and dust can be combined with a binder to'form a coherent'sheet, which resembles leaf tobacco and whichis' commonly referred to as reconstituted tobacco. One method-for making reconstituted tobacco of this general character is disclosed in United States Patent No.- 2,7 34,5 10, wherein the tobacco fines and dust are' applied to a binder made of carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose or a suitable salt thereof. The binder, in' such com-' positions, ranges from about 5% to about 50% of the weight of the tobacco employed. United States.Patent No'l 2,708,175, describes a binder for reconstitutedtobacco citrus'fr'uits; However, the addition of cellulosicbinders further increases'the amount'of cellulosicmaterialinthe product tends-to create an acridand bitter' smoke, when the product is used to makecigaret'tes. The natural hydrophilic celloid gums such as guar gum, locust bean gum, alginand other commonly used materials, such as Irish moss, have additional disadvantages. These materials contain proteins and other materials not found intobacco which add distinctive flavors of their own to to,- bacco products during smoking. Thus, Frankenburg, in describing the use of various water-soluble polysaccharides derived from plants other thanvtobacco, teaches that care should be exercised that they must be in a state of refinement. Frankenburg teaches that these materials should be free of extraneous matter containing compounds of nitrogen, particularly proteins, and compounds "of sulfur, phosphorus and the halogens; i.e., compounds giving undersirable products of combustion or dry distilla; tion. Such refining is often a very tedious and ditlicu'lt operation.

The present invention makes possible the production of imp'roved reconstituted tobacco by a method which is simpler and more effective than the methods previously employed. The present method does not require refining of the binder and is, therefore, more easily and efficiently employed than other methods for making reconstituted tobacco. The reconstituted tobacco which is obtained in accordance with the present invention need not contain any additional cellulose or proteinaceo'us material which is foreign td'tobacco, since the binder which is employed may be derived solely from tobacco, and may beproduced in such a manner that it contains no materials other than those which naturally occur in tobacco. Thus, reconsti tuted tobacco produced in accordance with the invention, can beso formulated as to be similar in physical proper: ties and chemical composition to natural tobacco.

The term pectic substances 1 will mean those substances which are found in many plant products, and which consist, essentially of partially methylated galacturonic acids joined in long chains.

1 Note.'-Unless otherwise specified, the term "pectins will, for convenience, hereinafter be employed interchangeably with the term pectic substances.

t calcium salt of a polymer of galacturonic acid can be repreagent of the present invention. In the equation, R may resented as follow: be hydrogen, in which case the product is pectic acid,

cross-link cross-link COOCa CHaCOO H COOCa- OH OH B o E o an 0--0-H HCOC-H H-C-OCH HO-O-CH H-O-O in 3-O J; o bH AH na ()H (500011 (300011 Although pectins have long been known as constituents or R may be a monovalent inorganic cation, such as soof plant tissue, it has been found extremely difiicult to dium, potassium or ammonium, in which case the product separate pectins from the remainder of plant compositions is a soluble pectate. and to obtain them ashomogeneous compositions. The recovery of pectins from tobacco is even more difficult than the recovery of pectins fromother plants. In accordance with the present invention, tobacco parts r, I I are bonded together by tobacco pectins which are specialr 0554M; ly prepared by a novel process which yields these pectins in a form in which they can be employed as binder mate- OHJOOO rials. 0ur process for preparing tobacco pectins comprises J-0 I --o first reacting tobacco parts, .preferably in a form in which they present a large surface area, with an aqueous solu- Y 1 1 tion of a non-toxic reagent which is capable of reacting "0-4341 f HC O with and destroying the calcium and magnesium cross- H H H links in the pectinaceous substances which naturally occur in tobacco. After the calcium and magnesium cross-links 3 g 1 are destroyed, the tobacco pectins are liberated and made H H COOCHK Calcium pectate available for use as a binder. The tobacco pectins are then dissolved or dispersed in solution, or are at least suf- COOR CHQCOO OH ficiently released from the interstices of the tobacco mass so that they form a coating on the surface thereof. Tobacco 5 l fi pectins which are dissolved or dispersed in the treating r solutions, may thereafter be precipitated or deposited from H- -0- ZCa the solution, so that they become available for use as a H H Product havinglower binder material. In this way, the tobacco parts can be v E & Cation concentration bonded together by a binder material which is made of 40 (g g g ggi fgg ingredients that are closely related to the naturally occur- H H COOCHJ treating solution ring ingredients of tobacco. The bonding can be accom- Pectic acid or soluble peztate plished without the need for the purification of the tobacco pectins, inasmuch as any materials which are present are closely related to the materials which are normally present in tobacco and, thus, do not add any undesired v qualities to the tobacco. r

The tobacco parts which can be employed in the present invention including tobacco leaves, Shims and Stalks, a In one embodiment of this invention the reagent which i t of these, Whether in sheet, fl par l t or canbe, and preferably is, in aqueoue solution acts by other form' Preferably, the Parts are g Cut other 0 forming a precipitate with the calcium or magnesium, in

wise prepared in a f rm w h p ts} large Surface which case, it can be a water-soluble monovalent metal area. The portions o the Plant comlmslngfhe Stem salt of the formula M X wherein M is a monovalent ini h i and Often fefel'fed as tobacco petlolesi are the organic cation, n is an integer having a value of 1, 2, or 3 pl f 2 g lals- 'Itohailtcobsttalks C01i1ta11'11) lesser and X 1s an anion which may be monovalent or polyvalent, amour! S 0 P mace us ma h 5 can a 6 6111 such that the calcium salt of the formula Ca X is essenployed. tially insoluble in the treating solution and p and q are In the first p of the Process of our Invention tobacco integers corresponding to the functionality of X. Mono- Pectins are liberflted from Pecthlaceous materials in valent cations which are effective include the alkali metals tobacco y reacting the Pectlnaceous mammals with a such as sodium, potassium and lithium, and also include reagent which, under the conditions of the reaction, is resuch monovalent cations as am active with the Calcium magnesium) contained ammonium ions (NR where igl yl h ig /f i h in them to for P P having a lower anion portion of the molecule may be CO PO HfO calcium ion, and, in the case of magnesium, magnesium HZPOF, and the m For example the Compound x ion,-concentration 2 in the treating solution than the natcom d be so urally occurring calcium (or magnesium) pectate-"Ihis reov lent i i i t i r gggi f gai t i n ix zlc sofblumtls agent may, for convenience, be hereinafter referred to as essential t 1 b1 mm car 9 e 15 a cross link destroy ng reagent. .i y wa er rnso u e. Addltional representative ex- The reaction may be generally repres d y q ample:1 of ,hpreclpitating agents are the orthophosphates,

n n u I m A. tlon I, which illustrates the reaction of one type of tobacco g i z zg fg Ca rblonatgs of sodlum potasmm Protop ctin (a calcium salt of a p lymer of galacturonic phates the g gg i gh 3;; gf s li g acid wherein calcium cross-links are resent wit the y 6 e1 er )a P h PO IIPO or H2PO4 Specifically, for example, when ammonium orthophosphate is used, the precipitate is cal- By concentration we mean concentration or activity as set cium and/ or magnesium ammonium phosphate. The pH forth in Glasstone. Textbook of Physical Chemistr 2nd Eamon, page 954' v Nos/grand 0mpany 11m y 7 of this reaction should be between about 5.8 and 10 and 5. the temperature may be as high as 400? C. but should, preferably, be between about 25 C. and about 135 C. for a period of from about 1 minute to about 24 hours. Preferred precipitating agents which may be employed are the alkali metal carbonates, for example, sodium carbonate and potassium carbonate. Particularly preferred precipitating agents which may be employed are the alkali metal phosphates and, most particularly, the alkali metal orthophosphates and the ammonium orthophosphates, such as the ammonium phosphates and ammonium orthophosphate, sodium orthophosphate, potassium orthophosphate, sodium dihydrogen orthophosphate, ammonium dihydrogen orthophosphate, potassium dihydrogen orthophosphate, diammonium monohydrogen orthophosphate, disodium monohydrogen orthophosphate and dipotassium monohydrogen orthophosphate.

Ina second embodiment, the cross-link destroying reagentacts by sequestering the calcium or magnesium, thereby removing the calcium or magnesium atoms by forming a complex therewith. Suitable reagents of this type include any sequestering agent which will form a complex or chelate with the calcium and/or magnesium, thereby removing the calcium and/or magnesium and making them unavailable for recross-linking with the pectin. Illustrative of such sequestering agents are ethylene-diamine-tetraacetic acid and similar amino acids, alkali metal polymetaphosphates such as tetra-metaphosphates, hexametaphosphates and trimetaphosphates, pyrophosphates and tripolyphosphates, such as sodium hexametaphosphate, tetrasodium pyrophosphate and pentasodium tripolyphosphate. The mechanism which occurs when a sequestering agent is employed is the formation of a chelate; calcium and magnesium ions are no longer available to combine with the pectate ions in solution. Many naturally occurring amines and peptides are also effective as sequestering agents for calcium and/or magnesium. Representative examples include alanine, aspartic acid, glycine, glycyl glycine, glutamic acid, serine, tyrosine and di-iodo-l-tyrosine. Amino acids that are effective as chelating solubilizing agents include beta alanine, N,N-diacetic acid; amino barbituric acid, N,N-diacetic acid; Z-amino-benzoic acid, N,N-diacetic acid; beta-aminoethylphosphonic acid, N,N-diacetic acid; beta-aminoethylsulfinic acid, N,N-diacetic acid and ethylenediamine-tetraacetic acid. The pH of this reaction should, preferably, be between about 4 and about 10 and the temperature should, preferably be between about C. and about 145 C. for a period of from about 1 minute to about 24 hours.

A cross-link destroying reagent may also function partially as a precipitating reagent, in accordance with the first embodiment of this invention, and partially as a sequestering agent, in accordance with the second embodiment of this invention. Such a reagent, for example, is diammonium monohydrogen orthophosphate (DAP), which is a particularly preferred material, in accordance with the invention.

In a third embodiment, the cross-link destroying reagent is an acid wash which forms the released but insoluble free pectic acid and soluble calcium and magnesium salts. Generally the acid wash will comprise an inorganic acid, such as hydrochloric acid, phosphoric acid, sulfuric acid or a similar acid, which will form soluble calcium and magnesium salts under the following conditions. Hydrochloric acid and sulfuric acid are particularly preferred. The acid may be employed as 0.25 N to 5.0 N solutions, but is preferably employed as 0.5 N to 1.0 N solutions.

The exact dilution and amount to be employed will vary with the particular acid which is used, it only being necessary that sufiicient acid be present to convert the calcium and magnesium present in the tobacco being treated to the calcium and magnesium salts of the acid. The acid treatment is preferably conducted at a temperature of from about -1 C. to about 50 C. The acid treatment comprises reacting the tobacco parts with the acid until the resulting mixture has a pH of from about 1.0 to about 25- Preferably, the pH is brought to from about 1.0 to about 1.7, the most desirable pH being between 1.15 and 1.55. This treatment will generally be conducted from about 10 minutes to 24 hours, depending in part on the size of the tobacco particles. The acid conditions which are necessary for this embodiment of the invention may be achieved by the use of ion exchange resins which may be used, with suitable recycle, to obtain the desired pH of the solution during treatment. The ion exchange resins may be used and regenerated in accordance with the usual practices for such resins.

Preferably, the mixture resulting from the acid treatment is then washed with water. This water wash step is preferably conducted at a temperature of from about 15 to about 35 C. and, preferably, distilled water is employed. When this wash step is employed, sufficient water should be used to remove the calcium and magnesium salts of the acids, which salts are formed in the above-described treatment; thus, there should be at least 2 volumes of water per volume of the mixture resulting from the acid treatment. The wash 'water is separated from the tobacco by any suitable means, for example, by conducting the wash in a centrifuge, filter press, Buchner funnel, or any other apparatus from which liquids can be substantially removed from solid materials.

In summary, in the first step of the first embodiment the treating agent Z-R attacks the calcium and/or magnesium cross-links of tobacco protopectin and forms a precipitate which is a salt of calcium and/ or magnesium, thus removing the calcium and/or magnesium from the protopectin and from the solution. In the first step of the second embodiment, the treating agent Z-R is a sequestering agent which forms a chelate of the magnesium and/or calcium from the tobacco protopectin and makes the calcium and/ or magnesium unavailable for recombining with the pectins. With certain reagents, such as DAP, the first step of the present process may comprise .a combination of the mechanisms of the first embodiment of this invention and the mechanism of the second embodiment of this invention. In the first step of the third embodiment of this invention, the treating agent Z-R is an acid which attacks the calcium and/or magnesium cross-links of the tobacco protopectin and forms the soluble calcium and/ or magnesium salts, which are then washed away from contact with the pectins.

In the first step of each of the first two embodiments, the pectin which results is in condition for release from the tobacco cell structure, R in Equation I being a monovalent inorganic cation such as sodium. In the first step of the third embodiment, the insoluble pectic acid resulting from the acid treatment must be reacted with an alkaline material before it is in condition for release from the tobacco cell structure.

The acid treated pectins are placed in condition for release by bringing the mixture resultin from the acid treatment, and preferably, after the water wash described above, to a pH of from about 5.0 to about 10.5 and, preferably, from about 6.3 to about 8.5, by the addition of an alkaline material. Suitable alkaline materials include ammonium hydroxide and alkali metal hydroxides, for

- example, sodium hydroxide, potassium hydroxide and lithium hydroxide, and alkali metal salts, such as sodium bicarbonate, sodium carbonate, sodium phosphate, and similar salts to convert the ,pectic acid to a soluble form. The alkaline material may be any water-soluble compound containing a monovalent inorganic cation and capable of producing hydroxide ions when dissolved in 7 cross-links, they should be released from the interstices of the tobacco. That is, they will be made available to the solution or suspension or, in certain instances, they will be merely deposited on the surface of the tobacco particles. This comprises the second step of the process of the present invention. In embodiments l and 2, this release or second step may be accomplished concurrently with the first step by reacting with the solution of the treating reagent. In embodiment 3, however, as indicated above, the insoluble pectic acid resulting from the treatment should be reacted with an alkaline material before it can be released. In such event, the release'may be concurrent with the addition of the alkaline material due to a washing action.'In any case, additionaltreating liquid or water may be used to effect the release through a washing action of the treated tobacco particles.

The tobacco pectins can be recovered by concentrating the solution or suspension in which they are present until they precipitate. This precipitate might also be characte rized as an intractable mass, since the pectin solution, upon concentration, generally becomes progressively more viscous until it finally dries to leave a deposit in a'glassy solid state.

While the tobacco pectins can be separated and purified before use as a binder in reconstituted tobacco sheets, they are preferably employed just as they -are produced in situ, i.e., from the slurry in which they are in combination with the treated tobacco plant parts from which they were obtained, the entire combination comprising the binder for reconstituted tobacco sheets or, under some circumstances, the entire combination comprising essentially the entire components of a reconstituted tobacco sheet. By using the entire mixture, no original tobacco flavors are lost, all of the tobacco is employed, and no expensive and time-consuming refining operations are required.

Although it is not necessary, the thixotropic properties of solutions containing soluble pectins can be adjusted in the preparation of a cured sheet by the addition of such materials as calcium chloride. If any complex or precipitate formed in the first step of this process is present with the soluble pectates, the thixotropic properties of the mixture can also be adjusted by adjusting the pH to precipitate calcium and magnesium pectates.

A preferred preliminary step, in accordance with the present invention, comprises washing the tobacco plant parts, which are preferably ground or cut to a relatively small size, with cold water. This water wash serves to remove impurities which might otherwise hinder the subsequent treatments in accordance with the present invention. It is particularly desirable to employ such a cold water washing step when alkali metal carbonates are employed as the reagent in the first step. Generally, suf ficient water should be used during such a water wash operation to cover all of the tobacco plant parts present. The temperature of the water may be between 1 C. and .100 C., but is preferably about 20 C., and the water wash should generally continue for a period of from about /2 to 2 /2 hours. Agitation during the wash is desirable, but not necessary. After the water wash has been completed, the water can be removed from the tobacco parts by filtration, decantation or other suitable means. 7

As discussed above, a particularly preferred embodiment involves the use of an ammonium or alkali metal orthophosphate, such as diammonium monohydrogen orthophosphate (DAP), for the release of the tobacco pectins. The DAP will, generally, be added to the tobacco plant parts, which may, for example, be bright tobacco parts, burley tobacco parts, or a mixture of the same, in an aqueous solution. The concentration of the DAP in the aqueous solution is not critical, but will, generally, be in the range of 0.5-5.0% by weight. The DAP and water may be added separately to the tobacco. The amount of DAP should, preferably, comprise from about 0.01 to about 0.5 part, and, most prefer ably, frorn 0.05 to 0.35 part (by weight) per part oftobacco being contacted. A humectant, such as glycerin or triethylene' glycol, may be present, if desired, at about '0.5 to l partv per part of DAP. The temperature during'the DAP treatment'of the tobacco may vary between room temperature,

and about 190 F. or higher, depending on the type of tobacco being treated. Under pressure, even higher temperatures may be employed. The PH of the mixture is, preferably, maintained at a value about 7.1 to 9.0, which may conveniently be accomplished by the addition "to the solution of concentrated aqueous ammonia. By agif tating or stirring such a mixture under the above-described conditions for from about 1 minute to about 1 day, and, preferably, from about 1 hour to about 5 'honrs, the tobacco pectins are liberated, 'relea sed and deposited in the tobacco plant parts to form a binder composition. The resulting mixture may then be refined, for example, in a disk refiner, until substantially all the pulp (in excess of the water present), can be shaken through a screen of approximately 18 mesh to produce a binder composition which is ready for use in the manufacture of reco nstituted tobacco sheets. i

The term tobacco pectins as used throughout this specification means liberated tobacco pectins and com-- prehends pectins which have been freed or liberated from tobacco and are, therefore; not bound into the tobacco structure, as differentiated from the insoluble, naturally-occurring protopectins which are found into a plant cell structure-The term includes the free pectinic or pectic acid, as well as soluble salts such as the sodium, potassium, ammonium, pectates and pectinates, and insoluble salts such as the calcium and magnesium pectates and pectinates depending on what'method is employed to liberate and obtain them from the naturally occurring insoluble protopectins.

The tobacco pectins produced or liberated in situ or isolated by means of this invention can be used as the sole binder material for reconstituted tobacco, i.e., no other materials need be added to make the sheet. They can be sprayed, extruded or cast, thus facilitating appli cation onto a moving belt carrying tobacco dust. Under proper conditions of formulation and processing, reconstituted tobacco made'with the tobacco pectins produced by this invention exhibit excellent physical and aromatic properties. The ultimate tensile and wet strengths of the reconstituted tobacco are good. While no other materials need be added to the pectinaceous binder, other materials can be added, if desired. For example, organic acids and preservatives which may in themselves be of tobacco origin, may be added. Plasticizers, such as glycols and polyglycols, and humectants, such as glycerin, may also be added, if desired. In addition, the gel strength of the tobacco pectins can be regulated by partial precipitation to control such rheological properties as viscosity, fluidity and elasticity. Other additives or dispersants may be added in small amounts to regulate slurrying qualities, provided, however, that such substances are not added in large enough quantities to adversely affect the flavor or aroma of the final product. Furthermore, the tobacco pectins can be combined with water-soluble gums or water-dispersible gums commonly used as binders for tobacco sheets such as methyl cellulose, sodium carboxymethyl cellulose, guar gum, locust bean gum, or alginates, although it is preferred to minimize or eliminate such additions in order to obtain a product which most closely resembles natural tobacco.

The product from treating the tobacco plant parts in accordance with the methods of the present invention prepared composite slurry or easily molded isolated pectinaceous mass is as a binder for ground tobacco and for the making of corresponding tobacco products suitable for smoking. Sheet material of widely dilferent properties may be formed by suitable variations in the manner of forming. One method and product comprises flowing the composite slurry onto a moving belt and applying a layer of dry ground or fragmented tobacco to the wet adhesive surface. If desired, there may be first applied to the belt a layer of the tobacco, followed by a layer of the binder, and then a top layer of the tobacco. Various additives may be included with the ground tobacco such as flavorants, plasticizers and aromatic substances. The web is ultimately dried and then suitably moistened and rolled up, Such methods of forming continuous sheets are known generally in the art and the details need not be further described. Representative of this procedure is the apparatus and method disclosed in U.S. Patent 2,734,513.

Another method of forming a reconstituted tobacco product, with the slurry of the isolated tobacco pectins as a binder, comprises mixing ground tobacco thoroughly therewith into a mass of dough-like consistency and then casting the mass in sheet form onto a moving belt surface followed by drying and remoistening in accordance with the known procedures. Representative of this procedure is the apparatus and method disclosed in U.S. Patents 2,708,175 and 2,769,734. Obviously, the reconstituted tobacco may also be formed by molding or other suitable means.

A. particularly preferred aspect of the present invention comprises employing, as a binder or directly, the mixture of tobacco and tobacco pectins which have been produced in situ, without any separation steps and without the necessity for any additional adhesive' materials.

The following examples are illustrative:

EXAMPLE 1 Tobacco stems parts) were covered with cold water and leached for /2 hour. The water was then decanted and discarded. A treating solution, made from 1 part of sodium carbonate dissolved in 60 parts of water, was added to the leached parts. This mixture was heated at its boiling point for 30 minutes at atmospheric pressure and then for 20 minutes at 20 p.s.i.g. In the course of this treatment, the tobacco pectins were dissolved from the tobacco parts. The entire wet mass (pulp mixture) was dried and ground in a Waring Blendor so that it would pass through a 50 mesh screen. The resultant material had gel-like properties and was thixotropic in nature.

To this material was added 2 parts of glycerin, to serve as a humectant. The pH of the resulting mixture was adjusted to 6 by the addition of a solution of 10% hydrochloric acid. One gram of sodium carboxymethyl cellulose (CHC) was added to the mixture, giving a proportion of about 1 part of CMC to 10 parts of total solids in the mixture. Since it was desired to use this mixture as a sprayed tobacco binder, the CMC was employed in order to adjust the spraying qualities. The mixture of (a) treated tobacco plant parts, including the liberated tobacco pectins, (b) the sodium carboxymethyl cellulose and (c) the glycerin had a viscosity which was suitable for spray application of the mixture as a binding material for reconstituted tobacco. This material was sprayed on top of 'an undercoating of tobacco dust, of an 80 mesh size,

which had been dusted on a wet belt. Another coat of the tobacco dust was laid on top of the binder. In general an apparatus similar to that described in U.S. Patent 2,734,513 was employed. As in said patent, the reconstituted sheet was dried and was then humidified to the desired moisture content. The control in Table I was made in a conventional manner, using a relatively large amount of CMC in proportion to the pulped washed tobacco stems. The test data as observed are recorded in Table I.

TABLE I Sample Sheet 1 Sheet 2 Sheet 3 Control Part CMC 1 1 10 1 10 1/20 1 2. 5 Moisture (percent) 12.5 12.1 r 12. 7. 1 Tensile, Kg./in. .80 99 66 1. 2 Folded Tensile, Kg./in. 71 78 61 74 Elongation (percent) 2. 2 2. 3 2. 0 1. 9 Burning Rate, mg./sec. 1. 8 1. 8 1. 9 1. 7

lPart CMC per parts of total tobacco solids in the slurry (including tobacco pectins).

2 The percentage of moisture contained in the entire sheet (wet basis). 3 The breaking strength of a 10 cm. test strip which is 1 inch wide; an average of 10 strips.

4 One fold; test strip creased by application of a 400 gram weight for 30 seconds. 5 The percent elongation, at breakage, on the Instron Test Machine. 6 Free (nameless) burning rate of a single test strip, in air. 7 The reconstituted tobacco sheets made pursuant to this example were shredded and made into cigarettes. The test cigarettes, as well as control cigarettes made from standard reconstituted tobacco sheet, were submitted to a smoking panel for subjective testing. The panel found that the smoke of the cigarettes made by the method of this invention was significantly less harsh than the smoke obtained from the control cigarettes. A pleasing vanillin -odor was found to be transmitted into the aerosol phase of the smoke from the test cigarettes made employing reconstituted tobacco made by the present invention.

A EXAMPLE 2 ture was allowed to cool and the liquid was separated from thesolid materials. The solid materials were treated in a cider press to recover as much as possible of the remaining liquid. The liquid was added to a previously prepared coagulant bath which consisted of ethanol and hydrochloric acid, in an amount to adjust the pH of the coagulant'to about 1.0. The resulting mixture (which had a pH of about 3.0) was alternately stirred and allowed to settle for a period of two hours. At the end of this time the mixture was strained through a cloth sieve and the filtrate was discarded leaving a solid, gel-like mass, consisting essentially of pectinaceous materials combined with approximately 10 parts of liquor. The yield of pectinaceousthixotropic, soluble in water at a pH of about 6 and soluble in a sodium carbonate solution.

The tobacco pectins thus isolated were quite impure and had a color characteristic of tobacco. The solid mass was then redissolved in a sodium carbonate solution and the resultant solution waspoured into an acidified ethanol bath similar to the coagulant bath used earlier. The recoagulated solid was obtained by filtration and dried in an oven at 105 C. The dried tobacco pectins were in the form of an opaque, substantially colorless sheet. When the sheet was pulverized, a white powder was obtained having a distinct and pleasing odor similar to vanillin.

Ten grams of the dried tobacco pectins prepared above were swelled in ml. of cold water. The mixture was then added to a slurry consistin of 8.5 grams of refined kraft pulp dispersed in 200 ml. of water. The resultant mixture was homogenized in a Waring Blendor. Fourgrams of glycerin were then added to the mixture to serve as a humectant. The resulting mixture was cast into a binder film, using a Gardiner casting knife set to produce a sheet having a wet thickness of 50 mils. The physical properties of this sheet, after drying, were tested and were found comparable to the properties of conventional binder films. The physical test data are given in Table H. The; control material was made by mixing-pulp, which had it been refined with NaOH, with sodium carboxymethyl cellulose('CMC)- and a humectantflas is shown Table II. .I

QMC (sodium carboxymethyl cellulose) and pulp, as prepared by known methods and containing about 33% CMC.

Work coeflicient is proportional to the product of the tensile strength andthe elongation. Y

' Example 3 Zone: hundred grams of burley tobacco stems were covered with distilled water, leached for 30 minutes and then" drained. The washed stems were then mixed with a solution containing 10 grams of diammonium monohydrogen orthophosphate in 60O ml. of water. Theres'ultant slurry was heated for 1 hour at a temperature of from 90 to 100 C. T he pH of the reaction mixture, after completion of the reaction, was about 7. The entire reaction mixture was homogenized in a Waring Blendor. The solids content was determined to be by weight.

Two grams of glycerin, to serve as a humectant, were blended with 200 grams of the above reaction mixture. A film of 50 mil wet-thickness was cast from this mixture. The extruded film was found to have' the property of being able to slide olf a surface even when newly cast. After the film was partially dried, it was found that it could be peeled off a plate by hand, while still partially wet and then hung up to dry like wet cloth. This property provides definite advantages in the manufacture of tobacco products. i

,Physical tests were carried out on the dried film thus prepared and were also carried out on a control film made by using conventionally pulpe'd tobacco plant parts with. sodium carboxymethyl cellulose (CMC) as the binder. A film of binder as made in this example was burned and was found to givea pleasant aromatic smoke. The test data are given in Table III.

TABLE III Test Binder-Film, Control Binder 1 Tobacco pectin gel Binder-Film,

formed in sltu CMC plus Pulp Basis Weight, gins/it. 15.9 3. Moisture, percent 14. 3 14. o Tensile Coethcient 2 0.13 0.87 Instron Tensile, p.s.i. 2.0 3. 3 Elongation, percent 15. 1 4.1 Work Coefiicient, gm. cm./sq.

' Examples 4-10 In each of these examples, burley tobacco stems were covered with distilled water, leached for 30 minutes, and drained. One hundred grams of stems were treated with the'agent indicated in Table IV. The agent was dissolved in 600 ml. of distilled water in an amount sufiicient to make up a (by weight) solution. The leached tobacco stems were placed in said solution and heated in a steam bath for 1 hour at a temperature of from 90 to 100? C. (Except for the example in which Versene was employed. That example was conducted at room temp'era'ture.) A five ml. aliquot was taken from the resulting. mixture and mixed with ml. of ethyl alcohol in a graduated cylinder whereby a precipitate of tobacco pectins was obtained. The amount of precipitate in the graduated cylinder was observed. Each of these precipitates of tobacco pectins was suitable for use in the preparation of a reconstituted tobacco sheet in accordance'with the methods taught by the present invention. The results obtained inthese experiments are presented in Table IV below:

Table IV 4 Volume of coagulated Reagent: tobacco pectins Pentasodium Tripolyphosphate 1 5 Sodium Hexametaphos'phate 15 Diammonium m'onohydrogen orthophosphate (DAP) 15 Trisodium orthophosphate '15 Disodium monoh'ydrogen orthophosphate l5 Dih'ydrogen monosodium orthophosphate 5 Versene (tetra'sodiunisalt of ethylnediamine tetraacetic acid) l5 EXAMPLE v11 One'hundred grams of burley tobacco stems were cov-' ered with distilled water, leached for 30 minutes and drained. A solution of 10 grams of Versene (tetrasodium 'salt of ethylenediaminedetraacetic acid) in 600 ml. of

water was added to the stems and-the mixture was made.

basic with aqueous sodium hydroxide. The resulting mixture was then heated for 1 hour at room temperature. The entire mixture (a pulp) was homogenized in a Waring Blendor and the solids content was determined to be 5% by weight. A 200 gram portion of the pulp, thus prepared;

was combined with 2 grams of glycerin, as a humcctant, and then cast into a film of mils thickness by the use of aGardiner casting knife. The resultant sheet was found to have satisfactory physical properties and, upon burning, exhibited a very pleasing aroma.

EXAMPLE 12 of 10 grams of DAP per 100 grams of stems (which contained 12% moisture, by weight). The resulting mixture was boiled at low heat for one hour. The juice was then first expressed from the mixture by hand. Solids, forexample celluloseiand sand, were then further separated from the-juice by centrifuging. The clear juice fromboth operations was then mixed with 70% ethanol to form a gel, which was then squeezed out in cheese cloth. The gel was transferred to a Buchner funnel where it was washed first with acetone and then with ethyl ether. Finally, the gel was placed in a vacuum desiccator and dried. The gel was suitable for use in the preparation of a reconstituted tobacco in accordance with the teachings of the present invention.

. EXAMPLE l3 Burley tobacco stalks were separated into cortical tissue, Woody tissue, and pith. A sample of each was steam cooked with 10% sodium carbonate for 30 minutes at atmospheric pressure and for 20 minutes at 20 p,s.i.g. After this cooking, the woody tissue was still hard and could not be pulped in a Waring Blendor. The cortical tissue andpith were soft and pulpable. Each of these latter two preparations were suitable for use in the preparation of reconstituted tobacco.

were washed thoroughly in cold water, and then placed f in a boiling aqueous solution of 3 grams of diammonium monohydrogen orthophosphate and cooked for 5 minutes.

The mixture was then placed in a Waring Blendor. After a 'very short period-in the b'lndor, the mixture was converted to' 'a viscous, fine, impalpable slurryfwherein "the tobacco stem particles had Jbeeri'coinpletely separated to units of cellular size; impalpableinas's was suitable for use 'as a binder in reconstitutedtobacco."When remixe with. someot the. cold water washi gs r move 'in the first "step, the ,irnpalpabl'e mass immediately v fbeca me viscous andeventually jelled to a soft mass. f j

.For further comparison, a similarsampl'e' of coarse groundbr'ight stem fines 30 grams),was'dispersed in boiling" water and cooked 'fo'ra'bout :30 minutes with'three grams of diammonium" monohydrogen orthophosphate. ThepI-l of this mixture was brought to aj'value of 7;I by the addition to the mixture j'of 30% jaqu'e'ousfammonia. The granules of tobacco could thenbe refined "to a'palpable pulp, similar to thesoft ma'ss'produ'ced'in the'exper'iment described in the first part of this example.

EX MPLE,

.7 Burley tobacco I stems /2 pound iwere icovered with idistilled-watergallowedto stand.severali-hours and the water decanted. Thisste'p .was repeated severalntimes and finally the stems were covered with distilled water-"containing 50 ml. ofconcentrated' HCl and leftovernight at 24c C- i .97. 1, HT

v After standingovernightthe acidic: water was decanted and the stems washed repeatedly free of-iHCl untilithe wash water gaveno; pr'ecipitatewhentrezited .with silver nitrate solution. The stems were; then covered; with -distilled water containing grams of sodium carbonate-and left overnight-at 24 ;C. The zpI-Lof-zthe sample,.the-.fol-

lowing -.morni.ng,- was 831 The:- stems-.zwerei swollen; and soft and were easily disintegrated with the fingers and :the mixture could be homogenizedrand employed, as-a binder in reconstituted tobacco. I c

PL FQ I .The a p r tus mp o ediu this expe ment w la scale, eq m tc m r s a .ZO s n ea i st-bo om O n. pvs a n s Steel ta k fitt d. itha .Qowle h shear mixer. One hundred and forty-eightggallons of water were placed in the tank and heated to a temperature of 2 07" F. One hundred and twenty-eight pound'sof bright-tobacco (milled topass'a 6-msh per inch sieve-) ste'ms' -were added, while operating the Cowles mixer at a low speed. Almost immediately after the addition ofthetob'accmnine and one-quarter pounds of diammonium monohydrogen orthophosphate (technical grade'fwere added to the mixture. Ammonia (assaying 28%, =by-weight NI-l was added to adjust the pH to 7.1; The mixing speed was increased toT1 700 r.p.m.--After a .period:of 3=n1inutes the temperature of the mixture was 194"F. Most'of the particles in the mixturewere softenoughto' be smeared by hand and the mixture had a jelly-like consistencyz-The mixing was continuedfor 1- hour to obtain the highest possible state-of disintegration, although a -1'5' minute period appeared to be sufficient for this purpose-g; I The viscosity of the mixturewas found to be 10,400 cps. and itssolids content wasdound to be-8.05% by weight .-1 2. "n." I i. This mixture I ,was then employed as a binder, being pumped througha filter to-storage tanks and subsequently sprayed :on tobacco byithe' method and equipment described in U.S. Patent 2,7'34, 513;'It was appliedat' the rate of 3 grams' per square foot ;to form areconstituted tobacco sheet havingthe following physical properties? Basis weight, gins/n1 'i f f 10.2 Moisture content (percent b'y'weight) 13.0

Tensile, kg./in.' Fold tensile kg/in. a... I r i' ea 'sm, -7 t? 3 Weightof 'all the ingredients, including tobacco pulp, essentially free of moisture. t T 2 Eomputed byan integrator, attached to the Instronl'ensile eser.

:14 EXAMPLE 17 Burley tobacco stems were washed in cold water whereby, from about 75 to 80% of the natural contentof watersoluble: substances were .removed in the. wash water. The stems were then driedand groun'd and.used to make a binder as follows:

One hundred parts of water were brought to a temperature of 195 C.','.- and. tofthis wereadded:

-.7'.00 parts by weight (dry basis) of the washedburley stems, I v

1:05 parts diammonium phosphate, and

0.70 part of glycerin, as a humectant.

-..Con'centratedaqueous ammonia was then'added t bring the vpH "of the mixture'to a value of at least 7.1-but no higher, than 9.0. I v Y I The mixture was then stirred for one hour and subsequently; refined ini'a. disk type refiner until better than 99% of the? pulp1(in excesswater) could be shaken EXAMPLE 1&-

Burley tobacco stems were washed in cold water whereby, from about 75 to 80% of the natural content of watersoluble substances were removed in the wash water. The ,sv qins' Werethen used directly in the wet condition to make a binder as follows:

One hundred "parts of water werebroughtto atemperature of 195 C., and to. this were added:

a: 7...,Q0H parts by weight (dry basis) of the. washed burley :Ste'ms, v

1.05 parts diammonium phosphate, and 0.7.0 part-of a glycerin, as a humectant.

Concentrated aqueous ammonia was then added to bring the, pH of the mixture to a value of at least 7.1 but no higher than 9.0.

'1 a z I EXAMPLE 19' Burley tobacco stems were washed in cold water whereby, from 'about75 to 80% of the natural content of watersoluble substances were removed in the wash water. The stems were then dried and ground and used to make a binder as follows:

One hundred parts of water were brought to a temperature of 195 -C., and to this were added:

700- parts by stems, 1.05- parts diammonium phosphate, and 0.70 part of triethylene glycol (TEG), as a humectant. Concentrated aqueous ammonia was then added to bring the 'pH of the mixture to a value of at least 7.1 but no higher than 9.0. k The mixture was then stirred for one hour and sub,- S'equently refined in a disk type refiner until better than 99% of the pulp (in excess water) could be shaken through an 18 mesh sieve.

The resulting material was then employed as a binder for tobacco plant'parts to form :areconstituted tobacco sheet in a manner similar to that described in Example 16.

EXAMPLE 2o.

weight (dry basis) of the washed burley Burley tobacco stems were Washed in cold water whereby, from about 75 to of the natural content of wateraj ibaitiz .15 soluble substances were removed in the wash water. The stems were then used directly in the wet condition to make a-binder as follows: 2' One hundred parts of water were brought to a temperature of 195 C., and to this were added: v

7.00 parts by weight (dry basis) of the washedburley stems, 1 -zi 1.05 parts diammonium phosphate, :and 0.70 part of triethylene glycol (TEG), as a humectant. Concentrated aqueous ammonia was then added to bring the pH of the mixture to a value of at least 7.1 but nohigherthan9.0. The mixture was then stirred for one hour'and subsequently refined in a disk typerefiner-until better than 99% of the pulp (in excess water) could be shaken through an 18 mesh sieve.

The resulting material was then employed as abinder for tobacco plant parts to form a reconstitutedtobacco sheet in a manner similar to that described in Example 16.

EXAMPLE 21 Bright tobacco stems were washed in cold water whereby, from about 75 to 80% of the natural content of watersoluble substances were removed in the wash water. The

stems were then dried and ground and used to make a binder as follows:

One hundred parts of water were brought to a temperature of 100 C., and to this were added: 1

7.00 parts by weight (dry basis) of the washed bright (flue cured) stems,

1.05 parts diammonium phosphate, and

0.70 part of glycerin, as a humectant.

Concentrated aqueous ammonia was then added to bring the pH of the mixture to a value of at least 8.0 but no higher than 8.5.

The mixture was then stirred for four hours and subsequently refined in a disk type refiner until better than 99% of the pulp (in excess water) could be shaken through an 18 mesh sieve. r

The resulting material was then employed as a binder for tobacco plant parts to form a reconstituted tobacco sheet in a manner similar to that described in Example 16. I

' Example 22 Bright tobacco stems were washed in cold water whereby, from about 75 to 80% of the natural content of water-soluble substances were removed in the wash water. The stems were then used directly in the wet condition to make a binder as follows: I a

One hundred par-tsof water were brought to a temperature of 100 C., and to this were added: V

7.00 parts by weight (dry basis) of the washed bright (flue cured) stems.

1.05 parts diammonium phosphate, and

0.70 part of. glycerin, as a humectant.

The mixture was then stirred for four hours and subsequently refined in a disk type refiner until better than 99% of the pulp (in excess water) could be shaken through an 18 mesh sieve.

The resulting material was then employed as a binder for tobacco plant parts to form a reconstituted tobacco sheet in a manner similar to that described in Example Example 23 a l 0. I p r by: Weight (d y bright (flue cured) stemsj "I l y 1.05 parts diammonium phosphate, and v j v 070', part of triethylene glycol (TEG), as a humecfjCo'ncent'rated aqueous ammonia [was then adde'd'to 'bringthepH of the mixture to a'valve fofat least 8.0 but basis) the washed no h igherthan8. 5. jff; p f Theniixtur'eivas' thenstirred for four hours and subsequently refined in ya diskt'ype refiner until better than 99%fof thejpjulp '(injexcesslwater) could be shaken throughan'lfijmesh sieveg I if I (The resultin-g materil' as then' employed asa binder for tobacco pla'nt lpfarts .tof'form a reconstituted tobacco sheet in'a manner similar to that described in Example Example 24' Bright tobacco stems were washed in cold water whereby, from ahout75; to 80%;:of the natural content .of. water-solublesubstances were removed in the wash water. The stems were then useddirectly in the wet'condition to makeabinder as follows: One'hundred parts of' water? were brought to a temperature of 100 C., and to this were added: 2 V 7.00 parts by' weight"(dry..basis) of the washed bright (flue cured)stems, i 1 I. 1 1 1.05 .part's'diammonium phosphate, and r Y 0.70 part of --triethylene glycol' (TEG), as a humectant. v 4

J vConcentrated aqueous ammonia was thenadded to bring the pHaof the mixture to a value of at least 8.0 but no higherthan8.5.- -The. mixture was: thenxstirred for four hours and subsequently refined in a disk type refiner until better than 99% oi. the pulp (in excess water) could be shaken throughan 18 mesh sieve. A V

The resulting material was then employed as a binder for tobacco'plant-parts to form a reconstituted tobacco sheet'in amanner similar to that described in Example 16.

' Example 25 In the acid washtreatment of=tobacco parts for removal of alkaline earth minerals of the tobacco pectin, it is necessary to use quite large volumes of water if it is'desired toreduce the soluble anion content of the product-to a very low level. In this case, the use of a cationrexchange resin in a closed loop=system with the tobacco parts can make it possible to conduct the process with limited amounts of water and acid.

' The use of aresin (such" as Dowex 50w) in this way does not at all alter the principles of this form of treatment since the resin merely serves as a convenient reservoir ofacidity, continuously reconditioning efiluent fromthestems for reuse in the extraction. In the following example, the use of a cation exchange resin permits.the treatment of stems with a small fraction of'their natural nitrate ion content. Hydrochloric acidgis used; at, intervals toqregenerate the resin, but never directly contacts the tobacco.

The apparatus .used forion-e'xchange extraction of calcium from tobaccov stemsconsisted .of a 20 inch diameter washing column'fitted with ai20-mesh screen to supportthe charge of stems and a6 inch diameter Pyrex column-filled with l3lpounds ,of Dowex 50 W-8 acidform ion exchange resin-beads. The valvesand piping permitted a pump to be used either for recycling waters from the stem charge throu'gh the column or for separatelyreg'enerating the resin'with hydrochloric acid soluoperation, fifty pounds'of stems were, placed in the washing column'and rinsed with cold water until they were nearly free of 'water-solublernaterial. Then, the

., efiluent water's'werediverted through the ion exchange bed, returning by gravity to the top of stem charge. When the aqueous extract from one pound of burley stems was added to the recycling waters, a pH of between 1.5 and 2.0 was soon attained. During the treatment, the waters flowing from the resin column were monitored for their calcium content. (An appreciable precipitate from 50 ml. of resin efiluent treated with ammonium oxalate and made basic with ammonia indicated that the resin was saturated with calcium and needed to be regenerated with hydrochloric acid.) After sixteen hours of operation, and one regeneration of the ion exchange resin, the treatment was considered complete. A subsequent analysis showed that the calcium content of the stems had been reduced to less than one-sixth of the starting value of 4.5% CaO. The stems were rinsed twice with cold distilled water, pressed lightly, and redried in a tobacco processing oven to a final moisture content of about 4%, and ground to pass a 40 mesh screen. When a small sample of this powder was stirred with a little cold ammonia, it dispersed immediately, forming a stiff paste.

The resulting material was then employed as a binder for tobacco plant parts to form a reconstituted tobacco sheet in a manner similar to that described in Example 16.

EXAMPLE 26 Twenty grams of tobacco fines were washed in 1 liter of distilled water to get rid of the tobacco solubles. The fines were then admixed with l N hydrochloric acid until the mixture had a pH of 1.35. The pH was checked on a Beckman pH machine and the curves were also plotted against a titration of distilled water.

After titration, the caid was washed off the fines with three 400 ml. portions of distilled water. The fines were redisbursed in 400 ml. of distilled water and sodium bicarbonate was added to bring the pH to 7. The slurry was cast at a thickness of 3050 mils and dried to form a sheet and the resulting sheet was used as the adhesive binder in sandwich type reconstituted tobacco sheet.

EXAMPLE 27 Twenty grams of tobacco fines were washed in 1 liter of distilled water to get rid of the tobacco solubles. The fines were then admixed with 1 N hydrochloric acid until the mixture had a pH of 1.35. The pH was checked on a Beckman pH machine, and the curves were also plotted against a titration of distilled water.

After titration, the acid was washed off the fines with a 400 ml. portion of distilled water. The fines were redisbursed in 400 ml. of distilled water and sodium bicarbonate was added to bring the pH to 7. The slurry thickened to a viscous mass, which is evidence that the pectin had been solubilized. The slurry was cast at a thickness of 3050 mils and dried to form a sheet and the resulting sheet was used as the adhesive binder in sandwich type reconstituted tobacco sheet.

EXAMPLES 28-30 In each of these three examples, 20 gms. of tobacco fines were washed in 1 liter of distilled water to get rid of the tobacco solubles. The fines were then admixed with 1 N hydrochloric acid until the mixture had a pH of 1.35. The pH was checked on a Beckman pH machine and the curves were also plotted against the titration of distilled water.

After titration, the acid was washed off the fines with three 100 ml. portions of distilled water. The fines were redisbursed in 400 ml. of distilled water and a neutralization agent, as indicated in Table V, was added to bring the pH to the value shown in Table V. The slurry in each case thickened to a viscous mass which is evidence that the pectin had been solubilized. The slurry was cast at a thickness of 30-50 mils and dried to form sheets. The binders formed in this way were tested to determine their physical properties. These properties are shown in Table V below. The binder was used as the adhesive in a sandwich type reconstituted tobacco sheet.

TABLE V.PROPERTIES OF BINDER FILM -MADE BY ACID WASH PROCESS 1 Cone. NH-lOH. 2 15% KOH. 3 15% NaOH.

In the table the terms have the following meanings:

1. Integrator Count is proportional to the area under the stress-strain curve recorded by an Instron Test Machine.

2. Percent moisture=the percentage of moisture contained in the entire sheet (wet basis).

3. Percent elongation=the percentage elongation, at breakage, on an Instron Test Machine.

4. Tensile kg./in.=the breaking strength of a 10 cm. test strip which is 1 inch wide; an average of 10 strips.

5. Tensile coefficient=kg. per gm. of basis weight.

6. Work coefiicient gm., cm./ sq. in.=work coefiicient is proportional to the product of the tensile strength and the elongation.

EXAMPLE 31 The following ingredients were mixed into 900 parts of hot water and heated for 3 hours at 90 C., maintaining a pH of 7.0 by adding small amounts of aqueous ammonia.

Parts 87.9 mixed manufacturing byproducts and scrap tobacco 5.0 diammonium onthophosphate (DAP) 5 .0 glycerin 2.0 corn syrup 0.14 potassium sorbate The slurry was then refined in a one gallon capacity Waring Blendor for 5 minutes. With this amount of refining, the fibrous portion of the composition was seen to be well dispersed and thoroughly interlocked when examined in a droplet at a 1:9 dilution. This examination Was facilitated by the addition of a small amount of Congo Red dye.

The composition was a cast on stainless steel panels with an eight inch angle knife set for wet film thicknesses of 0.020 to 0.045 inch, and dried on a steam table.

The wet strength of the films was determined on a Scott Serigraph IP-2 using 1 inch width strips. The center of each strip was wet with distilled water on both sides and allowed to become thoroughly wet through (30 seconds or one minute) before actuating the tensile mechanism. These films showed the extraordinarily high wet film strength of grams at a film weight of 9.5 grams per square foot. A high wet strength is highly desirable in the preparation of cigarette filler, and assures that the subsequent manufacturing performance of this material will exceed that of the finest grades of leaf tobacco. Such strength is uniquely obtainable in the presence of the liberated form of pectin described in this disclosure.

We claim:

1. The process for the manufacture of reconstituted tobacco comprising treating tobacco plant partswhich contain pectins having alkaline earth cross-links with a solution containing an alkali metal carbonate reagent selected from the group consisting of sodium and potassium carbonate to destroy the alkaline earth metal crosslinks thus releasing the tobacco pectins from the interstices of the treated plant parts to form a slurry of pectins r and plant parts, maintaining said released pectins in ad- 19 2O mixture Wtih the said treated plant parts and finally shap- OTHER REFERENCES mg the 52nd slurry into a reconstituted tobacco artlcle. Translation of H Braconnot,s Articles in Annales de References Cited Chimie et Physique, vol. 30 (1825 p. 96, and vol. 28 (Researches on a New Acid of Universal Occurrence in UNITED STATES PATENTS. 5 Au Vegetab1es) 3,012,915 12/1961 Howard 13117 3,120,233 2/ 1964 Battista et a1 131-143 X MELVIN D, REIN, Primary Examiner.

3,121,433 2/1964 Plunkett et al 131140