U.S. patent application number 12/073650 was filed with the patent office on 2008-09-11 for methods of making reconstituted tobacco sheets.
This patent application is currently assigned to Philip Morris USA Inc.. Invention is credited to Juan G. Nicholls, Raquel M. Olegario, Richard G. Uhl.
Application Number | 20080216854 12/073650 |
Document ID | / |
Family ID | 39740417 |
Filed Date | 2008-09-11 |
United States Patent
Application |
20080216854 |
Kind Code |
A1 |
Nicholls; Juan G. ; et
al. |
September 11, 2008 |
Methods of making reconstituted tobacco sheets
Abstract
A reconstituted tobacco sheet having a high content of aerosol
former therein is manufactured by preparing an aqueous slurry
containing a tobacco material which is formed into a sheet. The
moisture content of the sheet can be reduced to less than about 50%
by weight before incorporating an aerosol former such as glycerin,
which can be at a temperature below about 40.degree. C., followed
by drying the sheet. The sheet can be trashed, blended with natural
tobacco strips, and shredded into a cut filler of a smoking
article.
Inventors: |
Nicholls; Juan G.;
(Midlothian, VA) ; Uhl; Richard G.;
(Mechanicsville, VA) ; Olegario; Raquel M.;
(Richmond, VA) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Philip Morris USA Inc.
Richmond
VA
|
Family ID: |
39740417 |
Appl. No.: |
12/073650 |
Filed: |
March 7, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60905834 |
Mar 9, 2007 |
|
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Current U.S.
Class: |
131/372 |
Current CPC
Class: |
A24B 15/12 20130101;
A24B 3/14 20130101 |
Class at
Publication: |
131/372 |
International
Class: |
A24B 3/14 20060101
A24B003/14 |
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.degree. C.; and drying the sheet.
2. The method of claim 1, wherein the aerosol former is a glycerin
solution.
3. The method of claim 2, wherein the glycerin is added in an
amount of up to about 50% by weight of the dried sheet.
4. The method of claim 1, 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.
5. The method of claim 2, wherein the glycerin solution is added in
an amount effective to produce a non-tacky sheet after drying.
6. The method of claim 2, 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.
7. The method of claim 1, comprising: (a) reducing a moisture
content of the sheet to about 45% or less by weight prior to
incorporating the aerosol former; or (b) reducing a moisture
content of the sheet to less than about 30% by weight prior to
incorporating the aerosol former.
8. The method of claim 1, comprising reducing a moisture content of
the sheet to less than about 30% by weight.
9. The method of claim 1, wherein: (a) the aerosol former is at a
temperature below about 35.degree. C.; (b) the aerosol former is at
a temperature below about 30.degree. C.; or (c) the aerosol former
is at a temperature below about 25.degree. C.
10. The method of claim 1, wherein the tobacco material is tobacco
leaf scraps, tobacco stems, tobacco dust created during tobacco
processing, and/or tobacco leaf prime lamina strip; incorporating
wood cellulose fibers into the aqueous slurry; and/or forming the
sheet is performed by a paper-making process.
11. The method of claim 1, wherein the aerosol former further
comprises a flavorant.
12. The method of claim 11, wherein the flavorant is licorice,
sugar, 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 or coffee.
13. The method of claim 1, wherein the aerosol former further
comprises a humectant other than glycerin.
14. The method of claim 13, wherein the humectant is propylene
glycol.
15. The method of claim 2, wherein the glycerin solution further
comprises an acetate compound.
16. The method of claim 15, wherein: (a) the acetate compound is
added in an amount effective to promote the reduction of one or
more constituents of the smoke of a combusted smoking article
incorporating the sheet as a cut filler; (b) the acetate compound
is ammonium acetate, calcium acetate, or magnesium acetate; (c) 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; (d) 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 (e) 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.
17. A method of making a smoking article, comprising: thrashing the
sheet of claim 1, blending the sheet with natural tobacco strips,
and shredding into a cut filler; and incorporating the cut filler
into a smoking article.
18. A method of making a reconstituted tobacco sheet, comprising:
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; separating the aqueous slurry into a solubles
portion and a fibrous portion; forming the sheet by a paper-making
process from the fibrous portion separated from the aqueous slurry,
without incorporating the solubles portion; reducing a moisture
content of the sheet to between about 30% and about 50% by weight;
incorporating an aerosol former comprising a glycerin solution into
the sheet at a temperature between ambient temperature and below
about 40.degree. C.; and drying the sheet to provide a
reconstituted tobacco sheet having a glycerin content of up to
about 50% by weight of the reconstituted tobacco sheet.
19. The method of claim 18, wherein the glycerin solution contains
about 50% glycerin by volume; the glycerin solution contains a
flavorant, humectant and/or an acetate compound; and/or
incorporating wood cellulose fibers into the aqueous slurry.
20. A method of making a smoking article, comprising: thrashing the
sheet of claim 18, blending the sheet with natural tobacco strips,
and shredding into a cut filler; and incorporating the cut filler
into a smoking article.
21. A smoking article comprising a tobacco rod, said tobacco rod
comprising cut filler disposed in a wrapper; said cut filler
comprising a blend of tobacco, 20 to 30% of said blend comprising
shreds of reconstituted tobacco sheet made by the method of claim
18.
Description
[0001] This application claims priority under 35 USC .sctn.119 to
U.S. Provisional Application No. 60/905,834 entitled METHODS OF
MAKING RECONSTITUTED TOBACCO SHEETS and filed on Mar. 9, 2007, the
entire content of which is hereby incorporated by reference.
BACKGROUND
[0002] 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.
[0003] 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 U.S. Pat. No. 4,341,228 (Keritsis et
al.), U.S. Pat. No. 5,724,998 (Gellatly et al.), U.S. Pat. No.
5,203,354 (Hickle), U.S. Pat. No. 5,584,306 (Beauman et al.), and
U.S. Pat. No. 6,216,706 (Kumar et al.).
[0004] 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 U.S. Pat. No. 3,255,706 (Selke), U.S. Pat. No.
4,542,755 (Selke et al.) and U.S. Pat. No. 4,182,349 (Selke).
SUMMARY
[0005] 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.degree. C., followed by drying the sheet.
[0006] 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.degree. 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
[0007] FIG. 1 is a flow chart illustrating an exemplary embodiment
of a method of making reconstituted tobacco sheet.
[0008] FIG. 2 is a flow chart illustrating a preferred embodiment
of a method of making reconstituted tobacco sheet.
DETAILED DESCRIPTION
[0009] 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.
[0010] 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.degree. C. Next,
in step 50, the tobacco sheet undergoes a drying process.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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).
[0015] 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.
[0016] Examples of aerosol formers include glycerin, propylene
glycol, ethylene glycol, dipropylene glycol, diethylene glycol,
triethylene glycol, tetraethylene glycol, and/or oleyl alcohol.
[0017] In one embodiment, an aerosol former solution 72 is
incorporated into the sheet at a temperature below about 40.degree.
C. In other exemplary embodiments, the aerosol former solution 72
is incorporated into the sheet at temperatures below about
35.degree. C., e.g., below about 30.degree. C. or 25.degree. C., or
at ambient temperature.
[0018] 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.
[0019] 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, 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.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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%.
[0024] 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.
[0025] 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.
[0026] With respect to the smoke biological activity, cigarettes
made from blends containing 20-30% 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.
[0027] 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%.
[0028] 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.
[0029] 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.
* * * * *