METHODS OF MAKING RECONSTITUTED TOBACCO SHEETS

Description

BACKGROUND

[0001] During the production and processing of tobacco products, tobacco by-products such as tobacco stems, leaf scraps, and tobacco dust produced during the manufacturing process (i.e., stemming, aging, blending, cutting, drying, cooling, screening, shaping and packaging) can be recycled to reclaim their useful tobacco content. In the past, such tobacco by-products have been formed into what is known in the industry as reconstituted tobacco sheets.

[0002] Once prepared, reconstituted tobacco sheets may be cut in a similar fashion as whole leaf tobacco to produce tobacco filler suitable for cigarettes and other smoking articles. Reconstituted tobacco sheets, methods, and/or apparatuses for production are also described in commonly assigned US-A-4 341 228 (Keritsis et al.), US-A-5 724 998 (Gellatly et al.), US-A-5 203 354 (Hickle), US-A-5 584 306 (Beauman et al.), and US-A-6 216 706 (Kumar et al.).

[0003] A process for manufacturing reconstituted tobacco sheets uses a paper-making machine in which water is drained from a fibrous slurry of tobacco particles, and sheet that is formed is subsequently treated and dried. Such paper-making machines are described in US-A-3 255 706 (Selke), US-A-4 542 755 (Selke et al.) and US-A-4 182 349 (Selke).

SUMMARY

[0004] A method of making a reconstituted tobacco sheet comprises preparing an aqueous slurry containing tobacco material. A sheet is formed from the aqueous slurry, followed by reducing a moisture content of the sheet to less than about 50% by weight. An aerosol former is incorporated into the sheet at a temperature below about 40°C, followed by drying the sheet.

[0005] In another embodiment, a method of making a reconstituted tobacco sheet comprises preparing an aqueous slurry containing tobacco material, wherein the tobacco material includes tobacco leaf scraps, tobacco stems, tobacco dust created during tobacco processing, and/or tobacco leaf prime lamina strip. The aqueous slurry is separated into a solubles portion and a fibrous portion. The sheet is formed by a paper-making process from the fibrous portion separated from the aqueous slurry, without incorporating the solubles portion, followed by reducing a moisture content of the sheet to between about 30% and about 50% by weight. An aerosol former comprising a glycerin solution is incorporated into the sheet at a temperature between ambient temperature and below about 40°C. The sheet is dried to provide a reconstituted tobacco sheet having a glycerin content of up to about 50% by weight of the reconstituted tobacco sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] 

FIG. 1 is a flow chart illustrating an exemplary embodiment of a method of making reconstituted tobacco sheet.

FIG. 2 is a flow chart illustrating a preferred embodiment of a method of making reconstituted tobacco sheet.

DETAILED DESCRIPTION

[0007] In accordance with a preferred embodiment, a method of forming a reconstituted tobacco sheet with a high aerosol forming content can provide the reconstituted sheets with up to about 50% by weight glycerin, while avoiding a tacky surface on the sheet.

[0008] FIG. 1 shows an exemplary embodiment of a method of making a reconstituted tobacco sheet. In step 10, an aqueous slurry containing tobacco materials is prepared. In the next step 20, a tobacco sheet is formed from the aqueous slurry. The moisture content of the aqueous slurry is reduced to under 50% by weight in step 30. After reducing the moisture content of the tobacco sheet, in step 40 an aerosol former is incorporated into the tobacco sheet at a temperature of preferably less than about 40°C. Next, in step 50, the tobacco sheet undergoes a drying process.

[0009] FIG. 2 shows a preferred embodiment of the method of making the reconstituted tobacco sheet. In a first step, tobacco materials 52 and water 54 are mixed to form an aqueous slurry 56. The tobacco materials 52 can be tobacco leaf scraps, tobacco stems, tobacco dust created during tobacco processing, and/or tobacco leaf prime lamina strip. For example, the tobacco material 52 can contain at least about 50% by weight stems, preferably about 70-80% by weight stems, with the balance containing tobacco leaf scraps and/or tobacco dust. Tobacco materials 52 can include other additives, such as wood cellulose fibers to improve the strength of the reconstituted tobacco sheet and allowing for lower stem content.

[0010] The aqueous slurry 56 is subjected to a pulping process 58 to produce a solubles portion 60 and a fibrous portion 62. For example, aqueous slurry 56 can be compressed or centrifuged to remove the solubles portion 60. Preferably, the solubles portion 60 is not reincorporated into the reconstituted tobacco manufacturing process, but discarded.

[0011] As shown in FIG. 2, in the embodiment, the fibrous portion 62 is subjected to a refining process 64 to convert the fibrous portion 62 to more closely approximate individual fibers for paper-making. The fibrous portion 62 is formed into tobacco sheets by a paper-making process 66 (e.g., Fourdrinier machine). During this paper-making process 66, the moisture content of the sheet is reduced by draining excess water through a wire mesh (e.g., Fourdrinier wire). For example, the moisture content can be reduced from a starting moisture content of about 98-99% by weight to about 95% by weight by pure draining. In another example, the moisture content can be reduced to about 85% if draining is coupled with vacuuming of moisture.

[0012] After the paper-making process 66 has been completed, the tobacco sheets are subjected to a moisture reduction process 68 to reduce the moisture content of the sheet. Preferably, the moisture content is reduced to less than 50% by weight, but greater than 30% by weight. In other exemplary embodiments, the moisture content is reduced to less than 45% by weight, less than 40% by weight, or less than 35% by weight. For example, the sheets can be placed on a steam-heated metal drum (i.e., Yankee dryer) to reduce the moisture content and optionally followed by smaller steam-heated surface dryers (i.e. can dryers).

[0013] After the moisture reduction process 68, an aerosol former solution 72 is applied to the sheet. For example, the sheets can be passed through a size press 70, in which the sheets are fed between two vertical or horizontal rollers, configured to apply an aerosol former solution 72 to both sides of the sheet. The aerosol former solution 72 can include other additives 74. In alternative embodiments, the aerosol former solution 72 can be sprayed onto the sheet, or the sheet could be immersed in the aerosol former solution 72.

[0014] Examples of aerosol formers include glycerin, propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and/or oleyl alcohol.

[0015] In one embodiment, an aerosol former solution 72 is incorporated into the sheet at a temperature below about 40°C. In other exemplary embodiments, the aerosol former solution 72 is incorporated into the sheet at temperatures below about 35°C, e.g., below about 30°C or 25°C, or at ambient temperature.

[0016] Glycerin is a preferred aerosol former for aerosol former solution 72. Glycerin forms an inert aerosol of glycerin and water vapor when combusted in a smoking article. For example, the glycerin aerosol former can be incorporated into the sheet as an aqueous glycerin solution containing about 20% to 80% glycerin by volume. In alternative embodiments, the glycerin solution can contain about 50 to 80% glycerin by volume. Preferably, the aqueous glycerin solution contains between about 75% to about 80% by volume glycerin. Attempts to use a solution of about 100% glycerin results in poor absorption of the glycerin into the tobacco material, resulting in a tacky surface, which can present difficulties in the manufacturing process.

[0017] The aerosol former solution 72 an also contain other additives 74, such as flavorants, humectants (other than glycerin), and/or acetate compounds. Examples of flavorants include licorice, sugar, fructose syrup, isosweet, cocoa, lavender, cinnamon, cardamom, apium graveolens, fenugreek, cascarilla, sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil, mint oils, cassia, caraway, cognac, jasmine, chamomile, menthol, cassia, ylang-ylang, sage, spearmint, ginger, coriander, coffee and the like. Examples of humectants other than glycerin include propylene glycol and the like.

[0018] Tobacco materials with a higher concentration of glycerin may also contain optional additives. Acetates have been identified as possibly promoting reduction in TPM cytotoxicity of tobacco smoke, especially in combination with glycerin. Acetate compounds may further enhance the reduction of TPM or phenolics in the smoke of a combusted smoking article. In one embodiment, the acetate compound includes ammonium acetate, calcium acetate, and/or magnesium acetate. The one or more acetate compounds are added in an amount effective to promote the reduction of catechol, hydroquinone, phenol, or TSNA in the smoke of a combusted smoking article incorporating the sheet as a cut filler.

[0019] As shown in FIG. 2, after passing the sheet through the size press 70, in which the aerosol former solution 72 is incorporated, the sheet is exposed to a drying process 76. For example, the drying process 76 can include passing the sheet through a tunnel or apron dryer.

[0020] In one embodiment in which the aerosol former solution 72 is glycerin, the glycerin solution is added in an amount effective to produce a non-tacky sheet upon drying. In another embodiment, the glycerin solution is added in an amount up to 50% by weight of the tobacco sheet after drying.

[0021] The ammonium acetate can be incorporated into the tobacco sheet in an amount between about 5 to 20% by weight of the sheet after drying, preferably about 10 to 12%. Calcium acetate can be incorporated in an amount between about 1 to 10% by weight of the sheet after drying, preferably about 4%. Magnesium acetate can incorporated in an amount between about 5-20% by weight of the sheet after drying, preferably about 8 to 10%.

[0022] After the drying process 76, in step 78 the sheet containing an aerosol former (e.g., glycerin) is thrashed or flayed with mechanical fingers into sized pieces similar to natural tobacco lamina strips or cut into diamond shaped pieces, between about two to four inches on a side. The reconstituted tobacco sheet pieces are blended with natural tobacco strips and the entire blend is shredded into a cut filler and incorporated into a smoking article. The overall reduction in TPM due to the dilution of tar in the tobacco smoke with an inert aerosol is proportional to the amount of glycerin incorporated in a smoking article.

[0023] The shredded tobacco sheet pieces ("STSP") may comprise approximately 5% to 60% of the blend of tobacco filler that is incorporated into the tobacco rod portion of the smoking article. At the upper end of the aforementioned blend inclusion range, the elevated glycerin content may tend to spot the wrapper of the tobacco rod, especially in humid conditions. The spotting effect can be ameliorated by selection of a wrapper paper having low spotting-propensity and/or by using a double wrap for the tobacco rod.

[0024] With respect to the smoke biological activity, cigarettes made from blends containing 20% to 30% STSP (comprising 2/3 base web, 1/3 glycerin) demonstrated that the biological activity, Ames and cytotoxicity, of total particulate matter (TPM), is reduced compared to a control cigarette without STSP, of similar filter construction and similar firmness.

[0025] In particular, at 20% inclusion rate of STSP, specific mutagenicity (Ames TA98 w/S9) was reduced by 35% and specific Neutral Red Uptake (NRU) cytotoxicity (1/EC50, ml/mg-TPM) was reduced by 27%. At 30% inclusion rate of STSP, specific mutagenicity (Ames TA98 w/S9) was reduced by 35% and specific Neutral Red Uptake (NRU) cytotoxicity (1/EC50, ml/mg TPM) was reduced by 39%.

[0026] Preferably, STSP may comprise approximately 20% to 30% of the blend filler, wherein the aformentioned reduction in biological activity can be achieved, the tendency for spotting is reduced and unfavorable impact on sensory perceptions from inclusion of the STSP is ameliorated.

[0027] While the embodiments described above have been described in detail, it will be apparent to those skilled in the art that various changes and modifications can be made, and equivalents employed, without departing from the scope of the appended claims.

Claims

1. A method of making a reconstituted tobacco sheet, comprising:

preparing an aqueous slurry containing tobacco material;

forming a sheet from the aqueous slurry;

reducing a moisture content of the sheet to less than about 50% by weight;

incorporating an aerosol former into the sheet, wherein the aerosol former is at a temperature below about 40°C; and

drying the sheet.

2. A method according to claim 1, wherein the aerosol former is a glycerin solution.

3. A method according to claim 2, wherein the glycerin is added in an amount of up to about 50% by weight of the dried sheet.

4. A method according to claim 2 or 3, wherein:

(a) the glycerin solution contains about 20% to 80% glycerin by volume;

(b) the glycerin solution contains about 50% to 80% glycerin by volume;

(c) the glycerin solution contains about 75% to 80% glycerin by volume; or

(d) the glycerin solution contains about 50% glycerin by volume.

5. A method according to any of claims 1 to 4, wherein forming the sheet further comprises:

separating the tobacco material into a solubles portion and a fibrous portion; and

forming the sheet from the fibrous portion without incorporating the solubles portion.

6. A method according to any preceding claim, comprising:

(a) reducing the moisture content of the sheet to between 30% and 50% by weight;

(b) reducing the moisture content of the sheet to about 45% or less by weight prior to incorporating the aerosol former; or

(c) reducing the moisture content of the sheet to less than about 30% by weight prior to incorporating the aerosol former.

7. A method of according to any preceding claim, wherein:

(a) the aerosol former is at a temperature below about 35°C;

(b) the aerosol former is at a temperature below about 30°C;

(c) the aerosol former is at a temperature below about 25°C; or

(d) the aerosol former is at ambient temperature;

8. A method according to any preceding claim, wherein the tobacco material includes tobacco leaf scraps, tobacco stems, tobacco dust created during tobacco processing, and/or tobacco leaf prime lamina strip.

9. A method according to any preceding claim comprising:

incorporating wood cellulose fibers into the aqueous slurry; and/or

forming the sheet by a paper-making process.

10. A method according to any preceding claim, wherein the aerosol former further comprises:

(a) a flavorant and/or;

(b) a humectant other than glycerin.

11. A method according to claim 10, wherein the humectant is propylene glycol.

12. A method according to any of claims 2-9, wherein the glycerin solution further comprises an acetate compound.

13. A method according to claim 12, wherein:

(a) the acetate compound is ammonium acetate, calcium acetate, or magnesium acetate;

(b) the acetate compound is ammonium acetate, which is added in an amount between about 7% to about 11 % by weight of the sheet after drying the sheet;

(c) the acetate compound is magnesium acetate, which is added in an amount between about 2.5% to about 5% by weight of the sheet after drying the sheet; or

(d) the acetate compound is calcium acetate, which is added in an amount between about 7% to about 9% by weight of the sheet after drying the sheet.

14. A method of making a smoking article, comprising:

making a reconstituted tobacco sheet by a method according to any preceding claim, thrashing the sheet, blending the sheet with natural tobacco strips, and shredding into a cut filler; and incorporating the cut filler into a smoking article.

15. A method according to claim 14, wherein the reconstituted tobacco sheet comprises 20% to 30% of the cut filler.

Ansprüche

1. Verfahren zur Herstellung einer rekonstituierten Tabakfolie, das Folgendes beinhaltet:

Herstellen eines wässrigen Breis, der Tabakmaterial enthält;

Bilden einer Folie aus dem wässrigen Brei;

Reduzieren des Feuchtigkeitsgehalts der Folie auf weniger als etwa 50 Gew.-%;

Einfügen eines Aerosolbildners in die Folie, wobei der Aerosolbildner eine Temperatur unter etwa 40°C hat; und

Trocknen der Folie.

2. Verfahren nach Anspruch 1, wobei der Aerosolbildner eine Glycerinlösung ist.

3. Verfahren nach Anspruch 2, wobei das Glycerin in einer Menge von bis zu etwa 50 % bezogen auf das Gewicht der getrockneten Folie zugegeben wird.

4. Verfahren nach Anspruch 2 oder 3, wobei:

(a) die Glycerinlösung etwa 20 bis 80 Vol.-% Glycerin enthält;

(b) die Glycerinlösung etwa 50 bis 80 Vol.-% Glycerin enthält;

(c) die Glycerinlösung etwa 75 bis 80 Vol.-% Glycerin enthält; oder

(d) die Glycerinlösung etwa 50 Vol.-% Glycerin enthält.

5. Verfahren nach einem der Ansprüche 1 bis 4, wobei das Bilden der Folie ferner Folgendes beinhaltet: Trennen des Tabakmaterials in einen Teil löslicher Stoffe und einen Faserteil; und Bilden der Folie aus dem Faserteil, ohne den Teil löslicher Stoffe einzufügen.

6. Verfahren nach einem der vorherigen Ansprüche, das Folgendes beinhaltet:

(a) Reduzieren des Feuchtigkeitsgehalts der Folie auf zwischen 30 und 50 Gew.-%;

(b) Reduzieren des Feuchtigkeitsgehalts der Folie auf etwa 45 Gew.-% oder weniger vor dem Einfügen des Aerosolbildners; oder

(c) Reduzieren des Feuchtigkeitsgehalts der Folie auf weniger als etwa 30 Gew.-% vor dem Einfügen des Aerosolbildners.

7. Verfahren nach einem der vorherigen Ansprüche, wobei:

(a) der Aerosolbildner eine Temperatur unter etwa 35°C hat;

(b) der Aerosolbildner eine Temperatur unter etwa 30°C hat;

(c) der Aerosolbildner eine Temperatur unter etwa 25°C hat;

(d) der Aerosolbildner Umgebungstemperatur hat.

8. Verfahren nach einem der vorherigen Ansprüche, wobei das Tabakmaterial Tabakblattausschuss, Tabakstiele, Tabakstaub, der bei der Tabakverarbeitung entsteht, und/oder Streifen aus hochwertiger Tabakblattlamina beinhaltet.

9. Verfahren nach einem der vorherigen Ansprüche, das Folgendes beinhaltet:

Einfügen von Holzzellulosefasern in den wässrigen Brei; und/oder

Bilden der Folie mit einem Papierherstellungsverfahren.

10. Verfahren nach einem der vorherigen Ansprüche, wobei der Aerosolbildner ferner Folgendes umfasst:

(a) einen Aromastoff und/oder

(b) ein anderes Befeuchtungsmittel als Glycerin.

11. Verfahren nach Anspruch 10, wobei das Befeuchtungsmittel Propylenglykol ist.

12. Verfahren nach einem der Ansprüche 2-9, wobei die Glycerinlösung ferner eine Acetatverbindung umfasst.

13. Verfahren nach Anspruch 12, wobei:

(a) die Acetatverbindung Ammoniumacetat, Calciumacetat oder Magnesiumacetat ist;

(b) die Acetatverbindung Ammoniumacetat ist, das in einer Menge zwischen etwa 7 % und etwa 11 % bezogen auf das Gewicht der Folie nach dem Trocknen der Folie zugegeben wird;

(c) die Acetatverbindung Magnesiumacetat ist, das in einer Menge zwischen etwas 2,5 % und etwa 5 % bezogen auf das Gewicht der Folie nach dem Trocknen der Folie zugegeben wird; oder

(d) die Acetatverbindung Calciumacetat ist, das in einer Menge zwischen etwa 7 % und etwa 9 % bezogen auf das Gewicht der Folie nach dem Trocknen der Folie zugegeben wird.

14. Verfahren zur Herstellung eines Rauchartikels, das Folgendes beinhaltet:

Herstellen einer rekonstituierten Tabakfolie mit einem Verfahren nach einem der vorherigen Ansprüche, Schlagen der Folie, Mischen der Folie mit natürlichen Tabakstreifen und Zerkleinern zu einem geschnittenen Füllstoff und Einfügen des geschnittenen Füllstoffs in einen Rauchartikel.

15. Verfahren nach Anspruch 14, wobei die rekonstituierte Tabakfolie 20 % bis 30 % des geschnittenen Füllstoffs umfasst.

Revendications

1. Procédé de fabrication d'une feuille de tabac reconstitué, comprenant ;
la préparation d'une pâte aqueuse contenant une substance de tabac ;
la formation d'une feuille à partir de la pâte aqueuse ;
la réduction d'un taux d'humidité de la feuille à moins d'environ 50% en poids ;
l'incorporation d'un agent de formation d'aérosol dans la feuille, l'agent de formation d'aérosol étant à une température inférieure à environ 40°C ; et
le séchage de la feuille.

2. Procédé selon la revendication 1, dans lequel l'agent de formation d'aérosol est une solution de glycérine.

3. Procédé selon la revendication 2, dans lequel la glycérine est ajoutée dans une quantité de jusqu'à environ 50% en poids de la feuille séchée.

4. Procédé selon la revendication 2 ou 3, dans lequel :

(a) la solution de glycérine contient environ 20% à 80% de glycérine en volume ;

(b) la solution de glycérine contient environ 50% à 80% de glycérine en volume ;

(c) la solution de glycérine contient environ 75% à 80% de glycérine en volume ; ou

(d) la solution de glycérine contient environ 50% de glycérine en volume.

5. Procédé selon l'une quelconque des revendications 1 à 4, dans lequel la formation de la feuille comprend en outre :

la séparation de la substance de tabac en une partie soluble et une partie fibreuse ; et

la formation de la feuille à partir de la partie fibreuse sans incorporer la partie soluble.

6. Procédé selon l'une quelconque des revendications précédentes, comprenant :

(a) la réduction du taux d'humidité de la feuille à entre 30% et 50% en poids ;

(b) la réduction du taux d'humidité de la feuille à environ 45% ou moins en poids avant d'incorporer l'agent de formation d'aérosol ; ou

(c) la réduction du taux d'humidité de la feuille à moins d'environ 30% en poids avant d'incorporer l'agent de formation d'aérosol.

7. Procédé selon l'une quelconque des revendications précédentes, dans lequel :

(a) l'agent de formation d'aérosol est à une température inférieure à environ 35°C ;

(b) l'agent de formation d'aérosol est à une température inférieure à environ 30°C ;

(c) l'agent de formation d'aérosol est à une température inférieure à environ 25°C ; ou

(d) l'agent de formation d'aérosol est à la température ambiante.

8. Procédé selon l'une quelconque des revendications précédentes, dans lequel la substance de tabac comporte des déchets de feuilles de tabac, des tiges de tabac, de la poussière de tabac créée durant le traitement du tabac, et/ou des bandes premières de parenchymes de feuilles de tabac.

9. Procédé selon l'une quelconque des revendications précédentes, comprenant :

l'incorporation de fibres de cellulose du bois dans la pâte aqueuse ; et/ou la formation de la feuille par un processus de fabrication de papier.

10. Procédé selon l'une quelconque des revendications précédentes, dans lequel l'agent de formation d'aérosol comprend en outre :

(a) un aromatisant et/ou :

(b) un humectant autre que la glycérine.

11. Procédé selon la revendication 10, dans lequel l'humectant est du propylèneglycol.

12. Procédé selon l'une quelconque des revendications 2 à 9, dans lequel la solution de glycérine comprend en outre un composé d'acétate.

13. Procédé selon la revendication 12, dans lequel :

(a) le composé d'acétate est de l'acétate d'ammonium, de l'acétate de calcium ou de l'acétate de magnésium ;

(b) le composé d'acétate est de l'acétate d'ammonium, lequel est ajouté dans une quantité entre environ 7% à environ 11 % en poids de la feuille après le séchage de la feuille

(c) le composé d'acétate est de l'acétate d'ammonium, lequel est ajouté dans une quantité entre environ 2,5% à environ 5% en poids de la feuille après le séchage de la feuille ; ou

(d) le composé d'acétate est de l'acétate de calcium, lequel est ajouté dans une quantité entre environ 7% à environ 9% en poids de la feuille après le séchage de la feuille.

14. Procédé de fabrication d'un article à fumer, comprenant :

la fabrication d'une feuille de tabac reconstitué par un procédé selon l'une quelconque des revendications précédentes, le battage de la feuille, le mélange de la feuille avec des côtes de tabac naturel, le hachage en scaferlati, et l'incorporation du scaferlati dans un article à fumer.

15. Procédé selon la revendication 14, dans lequel la feuille de tabac reconstitué comprend de 20% à 30% de scaferlati.

Drawing