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

Definitions

• ABSTRACT A method of making reconstituted tobacco material from stem material is disclosed which involves mechanically working by crushing or flattening stern particles, before it is subjected to any soaking or wetting operation, in such wise that the cellular structure of the stem material is disrupted without significant reduction in the size of the particles.
• the thus treated material is then refined, mixed with an aqueous carrier to form a slurry, shaped and then dried to a predetermined moisture level.
• the stem material may be sweated to expand the cellular structure.
• the present invention relates to the manufacture of reconstituted tobacco compositions of the type that can be manufactured without nontobacco additives. More particularly, this invention relates to processing improvements in the manufacture of reconstituted tobacco products containing substantial amounts of refined tobacco stems, said processing improvements providing a degree of control of product properties previously attainable only through the use of nontobacco additives.
• Processes for the formation of reconstituted tobacco compositions are well known in the art. Some of these processes have been eminently successful, others not so. Processes for the manufacture of reconstituted tobacco compositions may be classified as to whether nontobacco additives are or are not employed as product constituents. Prior to the present invention, all of the reconstituted tobacco processes which have achieved substantial commercial success have relied on the use of nontobacco additives to provide the required product properties. The reliance upon nontobacco additives to provide specific product properties is easy to understand. For example, if the reconstituted tobacco product burns with an undesirable black ash, the easiest solution involves the addition of a small amount of inorganic whitener.
• the reconstituted tobacco product is too brittle, add humectant; if it molds too rapidly, add fungicide; if it is the wrong color, add whiteners, darkening agents or food-approved colorants.
• humectant if it molds too rapidly, add fungicide; if it is the wrong color, add whiteners, darkening agents or food-approved colorants.
• fungicide if it is the wrong color, add whiteners, darkening agents or food-approved colorants.
• a nontobacco ingredient can be found which will contribute this property.
• nontobacco additives vary greatly in the extent to which they adversely affect these taste characteristics, they invariably contribute either nontobacco tastes or aromas on combustion or little taste and aroma on combustion. In the former situation, the presence of the nontobacco combustion characteristic contributes off-notes to the product, while in the latter case the absence of a tobaccolike combustion characteristic detracts from the product quality.
• This invention relates to novel processing innovations which eliminate undesirable product characteristics without the use of nontobacco additives, as well as improve the overall process economics and reproducibility.
• These processing innovations have resulted in the first percent tobacco reconstituted products which satisfy the stringent requirementsfor commercial acceptability. These requirements include tensile strength, color, ability to shape or form, and the numerous smoking qualities such as taste, aroma, burn and ash characteristics.
• the present invention provides a method for producing reconstituted tobacco compositions in economical and commercially acceptable form without the need for usage of nontobacco additives.
• This method comprises a series of processing steps, each with significance to the overall process economics or reproducibility or to specific product properties, which extend from the preparation of the tobacco to the ultimate formation of a smoking product.
• These novel processing steps and the novel combination of these steps result in an overall process which can transform normally unusable tobacco material into 100 percent tobacco reconstituted products of considerable commercial value.
• a further object of the present invention lies in the provision of novel, specific methods for preparing tobacco stem or stalk material for effective utilization in the manufacture of reconstituted tobacco compositions.
• tobacco stems shall include tobacco stems, tobacco stalks, or mixtures thereof.
• the working of the stems includes procedures of flattening and crushing. Working is intended to define the mechanical handling of stem so as to deform its structure without cutting or otherwise destroying the integrity of the stem particle.
• SWEATING OF STEMS The sweating of whole tobacco is normally employed to improve its flavor and smoking quality.
• the process as normally employed tends to reduce the content or effect of harsh ingredients, decrease enzyme activity and equalize the flavor characteristics of a variable starting material.
• Such sweated tobacco is directly employed in the manufacture of cigarettes or cigars.
• a hard force-sweat of tobacco stems alone prior to the refining operation has several novel and unforseeable results.
• the refined stems which have been hard force-sweated are found to result in reconstituted tobacco products which are significantly stronger than those prepared from the same stems without the hard force-sweating operation.
• the hard force-sweated stems of this invention when converted into reconstituted tobacco products are found to have substantially improved taste and smoking qualities as compared to the same products prepared without the hard force-sweat pretreatment.
• sweating is to define that exothernic process wherein fennentation of tobacco causes a temperature buildup and subsequent indigenous and in situ moistening or perspiring of the tobacco.
• Bulk sweating tobacco is piled unrestrained in open storage and at ambient temperatures and pressures for a period of at least one week.
• Case sweating merely defines a similar process, except that the tobacco instead of being freely piled is contained in boxes or cases open to ambient temperature and pressure conditions.
• the sweating of stems in bulk is preferably, according to this invention, carried out after they have been flattened or crushed, since in this form it is easier to attain the hard forcesweat condition.
• Unflattened stems do not, because of their low-bulk density, lend themselves to efficient high-temperature force-sweats.
• the worked stems are sweated in bulk in ambient temperatures in the range of l30-l50 F. It is extremely fortunate that the stem-working operation, which was described previously as having a desirable influence on the uniformity and time of refining, should also be a help in the ef-. fective hard force-sweating of the stems with its advantages in product strength and smoking quality.
• the flattened or crushed stems are placed in a tank containing 10 parts of water to 1 part of flattened stem.
• the mixture is agitated and allowed to soak for at least a half hour depending on the nature and size of the stem.
• the stem material rises to the surface and a tobacco liquor containing the tobacco solubles may be drawn off from the bottom of the tank. All of the tobacco liquor or any desired fraction of the tobacco liquor, as dictated by the product properties desired, may be removed and replaced with clear fresh water.
• the stem-water mixture is then refined or otherwise macerated in the normal manner.
• the stem solubles in the tobacco liquor contain a number of constituents, some whose origin was the soil and/or plant nutrients, which are known to cause or contribute to poor tobacco burn characteristics.
• these undesirable soluble constituents are chloride and phosphate ions which inhibit the burn, as is manifested in reductions in the free burn rate and burn duration of the ultimate reconstituted tobacco product, as well as in an undesirable dark-colored ash due to incomplete combustion.
• Magnesium ions which are also present in the stem solubles portion, have been found to cause flowering" of the ash and to adversely affect the ash coherency.
• the taste and smoking quality of the reconstituted tobacco product are improved through removal of stem solubles in several ways.
• leaf dust is generally superior to stem solubles in smoking quality
• substitution of additional quantities of the former for the latter in the reconstituted tobacco formulation upgrades the smoking quality of the product.
• a formulation comprised of 80 percent refined unwashed stems and 20 percent leaf dust may have acceptable strength properties.
• a formulation of similar strength may be prepared from only 40 percent refined washed stems and 60 percent leaf dust, with decidedly improved smoking quality.
• some tobacco stem types especially Burley stems, contain appreciable quantities of nitrates. Since potassium nitrate has limited solubility in water, cold storage of moist reconstituted tobacco products made from high-nitrate tobaccos frequently results in the growth of large unsighly potassim nitrate crystals on the surface of the product. Prewashing of the stems and removal of at least a portion of the stem solubles is generally sufficient to eliminate this problem.
• the flattened stems may be washed with a dilute solution of a mineral acid such as nitric acid or of an organic acid such as acetic acid.
• a mineral acid such as nitric acid or of an organic acid such as acetic acid.
• the flattened stems are introduced and soaked with occasional stirring for 30 to 180 minutes.
• the supernatent liquid is drained off and the stems are rinsed with clean water and allowed to drain. After the required amount of fresh water has been added for attainment of the desired pulp consistency, the stems are ready to be refined to the predetermined degree.
• SEQUENCE OF PROCESSING STEPS T he processing improvements described above may be severally or jointly incorporated into the manufacturing sequences of conventional processes for the manufacture of 100 percent tobacco reconstituted products to provide improved tobacco products.
• the flattened and sweated stems are then thrashed so that d.
• the flattened stems retained on the 4-mesh screen are suspended in approximately 10 times their weight of water and, after a suitable soaking period for extraction of solubles, all or a suitable portion of the tobacco liquor is drained from the tank.
• the amount of solubles removed depends on the degree to which it is desired to raise tensile strength, lighten color, improve burn properties and ash color and coherence, improve smoking quality and remove crystallizable nitrates.
• Tobacco liquors removed in the washing process may be replaced with water so that viscosity is maintained.
• the stem-water mixture is now refined by milling or grinding, suitable techniques being described for example in US. application Ser. No. 661,762 by Light and Osborne.
• dry ground tobacco dust or the undersized stem which is also otherwise waste material
• Dry ground tobacco dust which generally weakens the ultimate product may be added in amounts which usually range from 20 to 70 percent of the final product, depending on the strength characteristics of the refined stem pulp, the degree to which the stems were washed and the requirements for strength, burn and smoking quality in the reconstituted tobacco product.
• the undersized portions of the thrashed flattened stems, dust and other tobacco leaf fragments may be added to the stem pulp during the course of its refining. This alternative eliminates the need for dry grinding. During this step of addition of dry tobacco proper moisture and viscosity levels are maintained to provide a consistency suitable for shaping.
• the resultant aqueous mixture of refined tobacco stems and tobacco dust may be deaerated by the application of suitable vacuum with the proper amount of agitation to facilitate removal of air. Deaeration results in stronger products with a uniform appearance. It may be omitted when the strength of the undeaerated product is sufiicient for the application and when the appearance of airholes in the product is not objectionable or when the aqueous mixture is devoid of excess gas.
• An optional stem involves homogenization of the tobacco slurry composition prior to shaping, to provide a more uniform and mottle-free structure during the shaping process. Homogenizing may be accomplished by use of conventional techniques.
• the last step is the casting, molding or shaping and sub- EXAMPLE 1 Chopped Maryland Stems, l-2 inches average length, are put into a commercial Guardite"*(*Reg TM of the American Machine and Foundry Company for apparatus for the moisture treatment of tobacco.) unit and are steam softened for 3 hours using a standard Guardite softening procedure involving successive cycles of vacuum and steam to facilitate penetration of moisture and softening. At the end of this period, the stems are softened and have a moisture content of 35-45 percent. The stems are then crushed or flattened under pressure using a conventional Lanhoff crusher with a clearance of 1-2 mils between the flattening rollers.
• the size of the stems averages about three-fourths inches width, 3 inches length and about l-2 mils thick.
• the stems are then dried to about 8-15 percent moisture content and transferred to a threshing machine with y-inch concave openings.
• the number 4 crush fraction is separated; this is the fraction retained on a 4-mesh screen.
• the size of these crushed stems is approximately one-fourth-three-eighths inches in length and width.
• the particles that are too fine that are produced in the threshing process are separated and combined with the tobacco dust fraction used in reconstituted tobacco sheet formulations.
• the finer material may be included with the number 4 crush fraction in the subsequent refining operation.
• the refining of these stems is started after adding sufficient water to produce a solids content of 7 percent.
• a singleor a double-disc refiner may be employed to refine the stems.
• a twotank refining system is employed, in which the stem-water dispersion is pumped back and forth between two tanks, going through the refiner, located between the tanks, each time until the requisite degree of refining is attained.
• An alternate procedure is to use only one tank, and to continuously cycle from this tank through the refiner and back into the same tank until refining is complete.
• the use of precrushed stems allows better flow through the system, and the disruption of the cellular structure caused by crushing results in decidedly earlier separation and fibrillation of the stem structure, and with reduced power consumption. This ease of refining further manifests itself in lower stem pulp temperatures generated during the refining process, with beneficial effects on the ultimate product color and taste.
• the refined Maryland Stem were combined with Manila Leaf in a 70/30 ratio (Refined Maryland Stems/Manila Leaf) on a solids basis with additional water to produce a solids content of 8 percent for the total dispersion.
• the dispersion was cast on a moving stainless steel belt, dried by steam impingement on the underside of the belt, remoistened to about 23 percent moisture content and doctored in sheet form from the belt.
• the properties of this reconstituted sheet, at 23 percent moisture content and at a sheet thickness of 5.0 grams/ft. is shown below. Tensile properties were measured on l-inch width strips on a standard Scott Paper Tester.
• EXAMPLE 2 Pennsylvania tobacco stems are prepared for refining as in Example 1, except that after the Guardite softening and Lanhoff flattening operations, the flattened stems at 35-45 percent moisture content are subjected to a bulk or case sweating operation prior to the threshing operation to obtain the number 4 crush size.
• bulk sweating lots of 10,000 to 20,000 lbs. of flattened stems at 35-45 percent moisture content are piled in a bin at ambient temperature and pressure.
• a high-temperature force sweat condition is attained and a sweating temperature in the mass of l30150 F. results.
• the sweating is allowed to continuefor a period of 4 weeks, during which time the pile of stems is turned several times to insure a uniformly sweated product.
• the sweated stems are dried to about 8-15 percent moisture content and are threshed to the number 4 crush size as in Example 1.
• the stems were then suspended in water to produce a stem-water mixture at about 6 percent solids, and then refined tovan inverted Schopper- Riegler freeness value of minus 200 cc.
• the refined sweated Pennsylvania stems were then combined with Manila leaf dust in the ratio of 70/30 (Refined Sweated Pennsylvania Stems/Manila Leaf) and the dispersion was cast into a sheet as per Example 1.
• Example 2 Sheet Strength Type grams/inch 70/30 Unsweated Penna. Stems/ Manila Leaf EXAMPLE 3 The procedure of Example 2 was followed exactly, however, the refined sweated Pennsylvania stems were combined in a 70/30 formulation with Pennsylvania Leaf. The properties of the resultant sheet is as follows:
• Example 2 Sheet Strength Type grams/inch l 0 70/30 unsweated Penna.Stemsl Penna.Leaf 450 EXAMPLE 4 The procedure of Example 2 was followed exactly,.however, the refined sweated Pennsylvania stems were combined in a 70/30 formulation with Havana Seed Leaf. The properties of the resultant sheet is as follows:
• Example 5 The procedure of Example 2 was followed exactly except that as an alternate to bulk sweating the Pennsylvania Stems were case sweated.
• case sweating the flattened stems at 35-45 percent moisture content are loaded into cases, using about 350 lbs. to a case.
• the cases are stored in a room with a room temperature of about 90l 10 F. for 4 weeks.
• a sweating temperatui e inside the cases of l30l50 F. is attained, as measured by a spear thermometer inserted into the center of the case. No turning of the stems during sweating is required.
• Example 2 A reconstituted sheet substantially the same as made in Example 2 was obtained.
• EXAMPLE 6 Pennsylvania stems are softened, flattened, sweated, dried and threshed to produce it to A inch size pieces as in Example 2. Three hundred lbs. of these stems are charged into a suitable tank and 3,000 lbs. water added. The mixture is agitated for 10 minutes, then allowed to soak for 45 minutes. During this period the tobacco pieces rise to the surface. 1,000 lbs. of the water (containing tobacco solubles) is then drawn off from the bottom of the vessel through a drain valve which is equipped with a screen of such a design that it will retain tobacco stems but will allow small particles of sand or other foreign matter to escape with the efiluent. At the end of the draining period, sufficient fresh tap water is added to the batch to produce a stem-water mixture at 6 percent solids, and then refined to an inverted Schopper-Riegler freeness value of minus 200 cc., as in Example 2.
• the resultant sheet at 5.0 grams/ft. sheet weight and at 26 percent moisture content had a breaking strength of l,050 grams/inch. This is substantially stronger than the counterpart formulation shown in Example 2 in which the sweated Pennsylvania stems were not washed prior to refining.
• the sheet burn and taste properties were improved and a whiter and more coherent ash resulted.
• EXAMPLE 7 The procedure of Example 6 was repeated exactly, except with the removal of all of the soak water (full wash) instead of only 1,000 lbs. of the soak water (partial wash procedure).
• the resulting reconstituted sheet 70/30 fully washed sweated Pennsylvania stems/Pennsylvania leaf dust) averaged 1,450 grams/inch breaking strength. As a result of this substantially increased strength, increased proportions of leaf dust may be incorporated into the formulation if desired.
• EXAMPLE 8 Pennsylvania stems are softened, flattened, sweated, dried and threshed to produce M1 to 7% inch size pieces as in Example 2. However, instead of refining these stems at 6 percent solids and then subsequently combining the refined stems 70/30 with ground leaf dust as in Example 2, in this case the threshed to 1% inch stem pieces were blended 70/30 with Manila leaf portions (unground) and water added to produce an 8 percent solids mixture. This mixture is then refined and converted to reconstituted sheet as in Example 2. The resulting sheet had a sheet strength of 495 grams/inch at 24 percent moisture content. This is quite comparable to the 510 grams/inch at 23 percent moisture shown for the counterpart of this formulation in Example 2, where the stems were refined prior to the combination with a ground leaf dust compronent.
• EXAMPLE 9 Sweated Pennsylvania stems are prepared and refined as in example 2.
• the refined Pennsylvania stems are then combined with Manila leaf dust in the ratio of 30 parts refined sweat Pennsylvania stems to 70 parts Manila leaf dust, on a solid basis with additional water to produce a solid content of 9.5 percent for the total dispersion.
• the dispersion was cast, dried and remoistened to about 24 percent moisture content as in the previous examples, except that the casting thickness was such that the resultant reconstituted tobacco sheet had a thickness of 9.3 grams/square foot.
• the sheet strength of this product as measured on a 1-inch strip with a standard Scott Paper tester, was 360 grams/inc. The burn, taste, strength and thickness properties made it suitable for use as a cigar filler.
• EXAMPLE l0 Sweated Pennsylvania stems were prepared and refined as in Example 2.
• the refined Pennsylvania stems were not combined with leaf dust in this case, but were cast directly on a moving stainless steel belt at the refining solids content of 6 percent.
• the dispersion was cast, dried and remoistened to about 24 percent moisture content as in the previous examples, with the casting thickness at a level to produce a reconstituted tobacco sheet at a thickness of only 3.0 grams/square foot.
• the sheet strength of this product as measured on a 1- inch strip with a standard Scott Paper tester, was 720 grams/inch. Its taste, burn, strength and thickness rendered it particularly suitable as a cigar wrapper.
• Sweated Pennsylvania stems are prepared and refined as in Example 2.
• the refined Sweated Pennsylvania stems are then combined with a tobacco dust component which is one-half Manila leaf dust and one-half Maryland stem dust.
• the overall ratio of components is 70/ l 5/ l 5 (refined sweated Pennsylvania stems/Manila leaf dust/Maryland stern dust), on a solids basis, with additional water added to produce a solid content of 8 percent for the total dispersion.
• the dispersion is converted into reconstituted tobacco sheet as per the previous examples at a thickness of 5.0 grams/square foot and 23 percent moisture content as in Example 2.
• the sheet strength, measured as in the previous examples was 545 gram/inch.
• the resultant product was particularly suitable for uses as cigar or cigarette filler.
• the method of manufacturing a reconstituted tobacco product from stem particles consisting essentially of the steps of mechanically working by crushing said stem particles so as to disrupt their cellular structure without substantially reducing the size thereof, refining said worked stem particles to a predetermined size, mixing said refined stem particles with an aqueous carrier to form a slurry thereof, shaping said slurry into a predetermined mass and drying said mass to a predetermined moisture level.
• the method of manufacturing a reconstituted tobacco product from stem particles consisting essentially of the steps of mechanically working by crushing said stem particles so as to disrupt their cellular structure without substantially reducing the size thereof, sweating said worked stem particles so as to expand their cellular structure, refining said worked and sweated stem particles to a predetermined size, mixing said refined stems with an aqueous carrier to form a slurry thereof, shaping said slurry into a predetermined mass and drying said mass to a predetermined moisture level.
• a reconstituted tobacco product from stem particles consisting essentially of the steps of mechanically working by crushing said stern particles so as to disrupt their cellular structure without substantially reducing the size thereof, mixing said worked stem particles with an aqueous carrier, causing the soluble constituents of said stem particles to dissolve in said carrier, removing at least a portion of said carrier with said dissolved constituents, refining said soluble constituent-free stem particles to a predetermined size, mixing said refined stem particles with an aqueous carrier to form a slurry thereof, shaping said slurry into a predetermined mass and drying said mass to a predetermined moisture level.
• the method according to claim 9 including the step of sweating said stems for a period in excess of one week prior to the removal of said soluble constituents.
• the method according to claim 9 including the steps of mixing an amount of whole leaf not exceeding 70 percent by weight of stem particles with said stem particle prior to refinmg.
• the method of manufacturing a reconstituted product from stem particles comprising the steps of mechanically working by crushing said stem particles so as to disrupt their cellular structure without substantially reducing the size thereof, sweating said worked stern particles at a temperature in a range between F. through F.

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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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Cited By (11)

Citations (10)

• 1968
  • 1968-09-23 US US761789A patent/US3646943A/en not_active Expired - Lifetime
• 1969
  • 1969-09-19 IT IT40158/69A patent/IT1045516B/it active
  • 1969-09-19 GB GB46312/69A patent/GB1248102A/en not_active Expired
  • 1969-09-23 FR FR6932344A patent/FR2018680A1/fr not_active Withdrawn
  • 1969-09-23 DE DE19691948151 patent/DE1948151A1/de active Pending
  • 1969-09-23 BR BR212638/69A patent/BR6912638D0/pt unknown

Patent Citations (10)

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