Classifications

• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
  • A24B15/00—Chemical features or treatment of tobacco; Tobacco substitutes, e.g. in liquid form
  • A24B15/10—Chemical features of tobacco products or tobacco substitutes
  • A24B15/12—Chemical features of tobacco products or tobacco substitutes of reconstituted tobacco
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
  • A24B15/00—Chemical features or treatment of tobacco; Tobacco substitutes, e.g. in liquid form
  • A24B15/10—Chemical features of tobacco products or tobacco substitutes
  • A24B15/12—Chemical features of tobacco products or tobacco substitutes of reconstituted tobacco
  • A24B15/14—Chemical features of tobacco products or tobacco substitutes of reconstituted tobacco made of tobacco and a binding agent not derived from tobacco

Definitions

• the particularly valuable tobacco sheets which include cellulose fibers for chew resistance have been made possible by the dual nature of the solvent used in accordance with this invention which combines organic acid to dissolve the water-insoluble cellulose derivative with Water to hydrate the cellulose fibers.
• the water-insoluble cellulose derivative chosen for the production of a tobacco sheet or other coherent form must be soluble at normal temperature in the aqueous organic acid used as solvent. Since the preferred solvent is aqueous formic or acetic acid in the range of about 20% to 40% by weight concentration, the preferred water-insoluble cellulose derivatives are those which are substantially soluble in such solvent even though water-insoluble cellulose derivatives requiring aqueous formic or acetic acid of as high as about 80% by weight concentration may be used pursuant to this invention.
• the organic acid used as solvent pursuant to this invenion may be not only a mixture of formic and acetic acids but also a mixture of either or both of these acids with a somewhat less volatile acid like propionic acid or even a substantially non-volatile acid like lactic or citric acid. Poorly volatile and non-volatile acids are used as only the minor component in admixtures with formic or acetic acid.
• the use of a minor proportion of a non-volatile acid such as malic or tartaric acid as well as lactic or citric acid serves the dual purpose of acting as part of the organic acid solvent for the water-insoluble cellulose derivative and of plasticizing the tobacco product to render it more flexible and workable in making cigars especially when the product is a tobacco sheet applied as cigar wrapper.
• Dry-ground or pulverized tobacco may be formed into a coherent form having appreciable wet strength with the aid of a water-insoluble cellulose derivative dissolved in aqueous formic or acetic acid.
• a water-insoluble cellulose derivative dissolved in aqueous formic or acetic acid.
• plasticizing acid such as citric or lactic as part of the aqueous organic acid
• the pulp of refined cellulose fibers may be prepared from tobacco, particularly stems, or from the usual sources used in the pulp industry.
• the length of cellulose molecular chains is frequently determined by the viscosity of the cellulose derivative in a given solvent, at a given concentration and at a given temperature.
• degree of polymerization or viscosity grade of a water-soluble cellulose derivative like methylcellulose is usually established by the viscosity in centipoises (cps) at a temperature of C. for a water solution containing 2% by weight of the cellulose derivative.
• cps centipoises
• ethylhydroxyethylcellulose and cellulose acetate Another group of suitable binding agents comprises water-soluble grades of cellulose derivatives such as methylcellulose, hydroxyethylcellulose, methylhydroxyethylcellulose, ethylhydroxyethylcellulose, methylhydroxypropylcellulose and methylhydroxybutylcellulose which have been acetylated to the extent of rendering the cellulose derivatives substantially insoluble in water at normal and higher temperatures. For example, water-soluble methylcellulose of 8000 cps.
• ethylcellulose and cellulose acetate made with, respectively, lower ethoxyl and acetyl contents (but not low enough to make these cellulose derivatives substantially soluble in water) are soluble in less concentrated aqueous formic or acetic acid with an acid content going down to about 15% by weight.
• the specially made cellulose derivatives in contrast to the types which are commercially produced for solution in conventional organic solvents offer the advantages of obviating the use both of such highly concentrated organic acid as aqueous acetic acid of 80% by weight concentration and of the comparatively larger proportion of highly hydrated, refined cellulose fibers required to prevent cracking of a tobacco sheet during its manufacture with a cellulose derivative of the type offered commercially for solution in conventional organic solvents.
• a tobacco sheet made with the latter type of cellulose derivative is usually not sufficiently plasticized by water to make it stretchable enough for use as wrapper on cigars of the perfecto or like shapes; in such case, a watersoluble or highly water-susceptible binding agent is desirably used together with the cellulose derivative so that the resulting tobacco sheet can be plasticized by water to give it the desired degree of stretch or elasticity.
• the tobacco sheets of the invention may be moistened by a water spray, by contacting a wet roller or even by dipping.
• the moistening of the tobacco sheets with water is desirably controlled so that the moisture content then generally is in the range of about to by Weight inasmuch as such moistened tobacco sheets have the necessary stretch and other physical properties to be successfully applied as wrappers on cigars of even intricate shapes.
• the amount of water added to a tobacco sheet need not be more than that just required to make the workability of the tobacco sheet satisfactory for its intended use such as wrapper on cigars.
• the coherent tobacco products of this invention may be used in cigarettes, pipe tobaccos and like smoking products but the high wet strength and chew resistance that may be achieved in tobacco sheets made by this invention clearly indicate that such tobacco sheets are especially attractive for use as wrappers on cigars. Hence, further elaboration of the invention will be made in terms of its most valuable commercial application, namely, tobacco sheets used as wrappers on cigars.
• EXAMPLE 1 Burley tobacco stems cut to pieces of about 1 inch in length were admixed with water to form a 7.4% suspension which was placed in .a sealed autoclave for treatment in accordance with the process of US. Patent 3,076,729 to Garbo. Approximately 25% of the volumetric capacity of the autoclave was charged with commercially pure oxygen at an initial pressure of 700 p.s.i.g. (pounds per square inch gauge). While stirring, the stem suspension was heated until a temperature of about 300 F. was reached and then this temperature was maintained for a 20-minute period during which the pressure was held at about 1200 p.s.i.g. and with the help of added oxygen when needed.
• the suspension in the autoclave was rapidly cooled to a temperature of about 175 F. and discharged at .a pressure of about p.s.i.g. through a Rietz disintegrator fitted with a screen having /o, -inch openings.
• the thus treated suspension was filtered to discard the liquid and the residual stern material was so washed on the filter that the dry solids of the washed stem material had a ratio of total solids to water-insoluble solids, hereinafter called the wash ratio, of 1.2.
• the washed stem material was again dispersed in water to form a 6% suspension based on the dry solids of the washed stem material and this suspension with added titanium dioxide was repeatedly passed through a disc refiner until the refined stern fiber had a reverse freeness of 70 as determined by the Schopper-Riegler type beating and freeness tester.
• the titanium dioxide which was added to the stem suspension in the ratio of 1 part to 12.5 parts of dry solids in the suspension served two purposes, namely, lightening the color of the finished tobacco sheet and yielding a whitish ash when the tobacco sheet was smoked as wrapper on a cigar.
• the refined pulp of Burley stems was admixed with water-insoluble methylcellulose (39.5% methoxyl content) having an acid viscosity grade of 310 c.p.s. that had been dissolved in aqueous acetic acid .and was further admixed with a dry-ground blend of cigar-type tobaccos based principally on Wisconsin tobacco.
• the pulverized tobacco blend passed through -mesh screen (U.S. Sieve size) but only 85% passed through ZOO-mesh screen.
• This slurry was spread evenly on a stainless steel belt which was subsequently heated first with hot air impingement on the slurry-coated belt and as soon as enough water and acetic acid had been removed by evaporation to set the slurry coating on the belt was further heated with steam condensation on the underside of the steel belt.
• the dried coating on the belt was rehumi'dified to a moisture content of about 35% and stripped from the belt as a tobacco sheet. The moisture content was decreased to about 20% with the aid of infra-red lamps and the tobacco sheet approximately 0.002 inch thick was then wound up in rolls suitable for use on a cigarmaking machine.
• the tobacco sheet had a pleasing appearance and a brown color similar to that of some grades of cigar wrapper leaf tobacco.
• the Finch tensile strength of this tobacco sheet determined according to ASTM standard test D829-48, using an immersion time of 30 seeonds in water and a test sample of double width, was 125 g./mm. (grams per square millimeter).
• Ethylcellulose of 35.5% ethoxyl content was dissolved in aqueous acetic acid of 70% by weight concentration and was admixed with a dry-ground blend of 50% Sumatra and 50% Santo Domingo tobaccos, all passing through 100-mesh screen. The components were admixed to give a final slurry containing:
• Pulverized tobacco blend 150 Refined Burley stems (dry solids) 100 Ethylcellulose 50 Titanium dioxide 1 all in 45% aqueous acetic acid at a total concentration of 6% of the aqueous acetic acid.
• the thus prepared Burley stems were dewatered to a solids content of 15% and added slowly with high agitation to a solution of a mixture of 37.5 parts of methylcellulose (39% methoxyl content) and 12.5 parts of ethylcellulose (45% ethoxyl content) in glacial acetic acid until 100 parts (dry solids basis) of the stem material had been added. Water was then added slowly under high agitation to bring the acetic acid concentration to 80%. Finally, 100 parts of a blend of dry-ground Wisconsin tobacco and tobacco fines from cigar manufacture were added. The resulting slurry, having a solids content of 4.5% and a viscosity of 21,000 cps. at 20 C., was formed into a tobacco sheet as described in Example 1. The product was light in color, resembling a desirable cigar wrapper, and had properties suitable for conformance to shaped cigars.
• EXAMPLE 4 The procedure in Example 3 was followed in all details except that in place of 37.5 parts of the waterinsoluble methylcellulose, 25 parts of water-soluble methylcellulose (30% methoxyl content) of 1500 cps. viscosity grade was used, while the quantity of the ethylcellulose was doubled to 25 parts. The resulting tobacco sheet in appearance, physical properties and smoking qualities was very satisfactory as a cigar wrapper.
• EXAMPLE 6 The processed Burley stems of Example 3 were added to the extent of 50 parts (dry solids basis) to a solution of 20 parts of acetylated methylcellulose (prepared by acetylating water-soluble methylcellulose of 8000 cps. viscosity grade to 8% acetyl content) in glacial acetic acid. Sufiicient water was added to bring the acetic acid concentration to 35% and then 150 parts of dry-ground Java tobacco were admixed to yield a slurry with a solids content of 7% and a viscosity of 6500 cps. at 30 C.
• a slurry of refined cellulose fibers was prepared as described in Example 7.
• the processed Connecticut shade tobacco stem slurry and the refined cellulose fiber slurry were mixed together and added to the aqueous formic acid solution of the cellulose derivatives.
• dry-ground Connecticut shade wrapper tobacco cuttings as described in Example 7, Fiberfrax, and titanium dioxide were added.
• the final slurry had 7% solids in aqueous formic acid of 40% concentration and contained:
• the final slurry was converted into a tobacco sheet having a dry weight of 35 g./rnm. (grams per square meter), a tensile strength of 870 g./mm. and a Finch tensile strength of 170 g./mm. Used as a cigar wrapper, the product had high chew resistance and pleasing smoking qualities.
• the tobacco sheet made from this slurry as described in Example 1 was attractive in appearance and served as a cigar wrapper of good smoke taste and chew resistance.
• the tobacco sheet made from the final mixture had a pleasing color, conformed well to shaped cigars and was as chew resistant as wrapped tobacco of good quality.
• Flaked Burley stems were cooked as a 12.5% suspension in water in a heated kettle with stirring for one hour at a temperature of 120 F. This suspension was then passed through a Rietz disintegrator fitted with a screen having -inch openings, filtered and washed to a wash ratio of 1.2. The fibrous stem mass was redispersed in water to give a 5% suspension which was refined by 29 passes through a disc refiner and then one pass through a valve-type homogenizer at a pressure of 4500 p.s.i.g.
• Burley stems were slowly added under high agitation to a solution of 40 parts of waterinsoluble methylcellulose (39.5% methoxyl content) in 1630 parts of 80% aqueous acetic acid until 150 parts (dry solids basis) of the processed stems were incorporated. Then 150 parts of dry-ground Pennsylvania tobacco stems passed through ZOO-mesh screen) and 3 parts of fragmented Fiberfrax were added under high agitation. The mixture was slowly diluted under high agitation with water to reduce the acetic acid concentration to 30%. The final slurry had a solids content of 6.8% and a viscosity of 16,000 cps. at 11 C.
• Tobacco sheet produced from the final slurry as described in Example 1 had a good light-brown color and performed satisfactorily in all respects as a cigar wrapper.
• EXAMPLE 13 Flaked Connecticut shade tobacco stems were processed as described in Example 8. The resulting stem slurry was cooled to a temperature of 50 F. and added slowly with high agitation to a solution of 3 parts of acetylated methylcellulose (5% acetyl content, 29% methoxyl content, acid viscosity grade of 560 cps.) in 400 parts of glacial acetic acid until 97 parts (dry solids basis) of refined stem fibers were admixed.
• acetylated methylcellulose 5% acetyl content, 29% methoxyl content, acid viscosity grade of 560 cps.
• the final slurry in aqueous acetic acid of 25% acid content was cast as a thin coating on a stainless steel belt with a doctor blade and the coating was evaporated to dryness as the belt traveled over steam pan dryers.
• the resulting dry tobacco sheet was rehumidified, stripped from the belt and rolled up as described in Example 1.
• Tobacco sheet with a dry weight of 40 g./m. was produced from the resulting slurry as described in Example 1.
• This tobacco sheet had a Finch tensile strength of about g./mm. and good elasticity at a moisture content of 40%; it was a very acceptable wrapper on panatella-shape cigars.
• EXAMPLE 15 Seventy-five parts of the tobacco powder described in Example 14 were dispersed in 900 parts of a solution containing 25 parts of acetylated methylcellulose (10.1%
• Tobacco sheet with a dry weight of 50 g./m. was produced from the resulting slurry and had a tensile strength of 475 g./mn1. and a Finch tensile strength of 130 g./ mm.
• this tobacco sheet was very similar to the product of Example 14.
• Example 15 illustrates the aspect of the invention of using a water-insoluble acetylated cellulose derivative which was water-soluble prior to being acetylated.
• Tobacco sheets of high resistance to disintegration when moistened can be produced with such water-insoluble acetylated cellulose derivatives whether dissolved in aqueous organic acid as shown in Example 14 or dissolved in organic solvent as shown in Example 15.
• Other organic solvents suitable for water-insoluble acetylated cellulose derivatives disclosed hereinbefore as being effective and desirable binding agents for the production of tobacco sheets include such solvent mixtures, preferably in the indicated weight proportions, as 9 ethylene chloride-1 ethanol, 4 benzene-1 methanol, and acetone-1 ethanol.
• the substantially water-insoluble methylcellulose found to be effective in producing a cigar wrapper type of tobacco sheet is one having a methoxyl content of at least about 38% by weight.
• ash-improving components such as titanium dioxide and finely divided ceramic fiber are effective when present to the extent of only a few percent, generally less than 3%, of the weight of the dry tobacco sheet.
• a coherent tobacco product with appreciable wet strength and adapted for smoking which comprises combining comminuted tobacco with a minor weight proportion, based on said tobacco, of a water-insoluble cellulose derivative dissolved in aqueous organic acid of not less than about by weight of organic acid content, the said organic acid having not more than two carbon atoms per molecule and converting the combined tobacco and solution of said cellulose derivative with drying into said coherent tobacco product.
• water-insoluble cellulose derivative is methylcellulose with a methoxyl content of at least 38% by weight.
• the process of manufacturing a tobacco sheet with appreciable chew-resistance and adapted for smoking which comprises preparing an aqueous suspension of highly hydrated refined cellulosic fibers, dissolving a waterinsoluble cellulose derivative in organic acid of not more than two carbon atoms per molecule, mixing said aqueous suspension of fibers, the organic acid solution of said cellulose derivative and dry-ground tobacco so as to yield a slurry containing a minor weight proportion, based on said tobacco, of said cellulose derivative with the resulting aqueous organic acid having a content of not less than 20% by weight of said organic acid, casting said slurry as a thin layer, and drying said layer to produce said tobacco sheet.
• water-insolu ble cellulose derivative is an acetylated form of an originally water-soluble cellulose derivative.
• water-insoluble cellulose derivative is predominantly methylcellulose wtih a methoxyl content of at least 38% by weight and a minor addition of acetylated methylcellulose.
• water-insoluble cellulose derivative is predominantly methylcellulose with a methoxyl content of at least 38% by weight and a minor addition of ethylcellulose.
• water-insoluble cellulose derivative is predominantly methylcellulose with a methoxyl content of at least 38% by weight and a minor addition of acetylated hydroxyethylcellulose.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacture Of Tobacco Products (AREA)

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Citations (6)

• 1966
  • 1966-12-01 US US598215A patent/US3416537A/en not_active Expired - Lifetime
• 1967
  • 1967-11-28 GB GB54101/67A patent/GB1203939A/en not_active Expired
  • 1967-11-29 BE BE707287D patent/BE707287A/xx not_active IP Right Cessation
  • 1967-11-30 DE DE1632151A patent/DE1632151C3/de not_active Expired
  • 1967-12-01 DK DK603067A patent/DK132253C/da not_active IP Right Cessation
  • 1967-12-01 CH CH1694967A patent/CH516285A/de not_active IP Right Cessation
  • 1967-12-01 NL NL6716408.A patent/NL159571B/xx not_active IP Right Cessation
  • 1967-12-01 SE SE16535/67A patent/SE356885B/xx unknown

Patent Citations (6)

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