U.S. patent number 3,861,402 [Application Number 05/408,655] was granted by the patent office on 1975-01-21 for smokable material and method for preparation of same.
This patent grant is currently assigned to Sutton Research Corporation. Invention is credited to Theodore S. Briskin.
United States Patent |
3,861,402 |
Briskin |
January 21, 1975 |
SMOKABLE MATERIAL AND METHOD FOR PREPARATION OF SAME
Abstract
The preparation of a smokable material in which a cellulosic
material containing a metal salt in the form of the carbonate,
oxalate pivalate or glycolate of calcium or magnesium or other
alkaline earth metals and mixtures thereof and a metal salt in the
form of chloride or sulfate of the metal is subjected to thermal
degradation in a non-oxidizing atmosphere at a temperature within
the range of 270.degree.-500.degree.C for a time sufficient to
effect a weight loss within the range of 40-75 percent and which
includes modifying the thermally degraded cellulosic material by
the addition of a binder in an amount within the range of 0.5-10
percent by weight and materials for strengthening and flexibilizing
the cellulosic material prior to degradation, including a starch,
sugar and dextrin and mixtures thereof, plus additives to improve
color, taste, aroma and moisture retention characteristics.
Inventors: |
Briskin; Theodore S. (Beverly
Hills, CA) |
Assignee: |
Sutton Research Corporation
(Los Angles, CA)
|
Family
ID: |
23617173 |
Appl.
No.: |
05/408,655 |
Filed: |
October 23, 1973 |
Current U.S.
Class: |
131/359 |
Current CPC
Class: |
A24B
15/165 (20130101) |
Current International
Class: |
A24B
15/16 (20060101); A24B 15/00 (20060101); A24b
015/00 () |
Field of
Search: |
;131/2,15,17,140-144 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3545448 |
December 1970 |
Mormon et al. |
3640285 |
February 1972 |
Briskin et al. |
|
Primary Examiner: Rein; Melvin D.
Claims
I claim:
1. A smokable material comprising the thermal reaction product, in
a non-oxidizing atmosphere, of a cellulosic material containing
10-30percent by weight of a compound selected from the group
consisting of the carbonate, oxalate, pivalate and glycolate of an
alkaline earth metal and 0.5-25 percent by weight of a compound
selected from the group consisting of a metal chloride and a metal
sulfate, in which the cellulosic material is exposed to a
temperature within the range of 275.degree.-500.degree.C for a time
sufficient to effect a weight loss within the range of 40-75
percent, and a flexibilizing and strengthening binder uniformly
distributed in the thermally treated cellulosic material in an
amount within the range of 0.5-10 percent by weight of the
cellulosic material.
2. A smokable material as claimed in claim 1 in which the
cellulosic material has been exposed to the thermal reaction
temperature for a time sufficient to effect a weight loss within
the range of 50-60 percent.
3. A smokable material as claimed in claim 1 in which the compound
is selected from the group consisting of the oxalate and carbonate
of calcium and magnesium.
4. A smokable material as claimed in claim 3 in which the carbonate
and/or oxalate of the alkaline earth metal is present in an amount
within the range of 15-20 percent by weight.
5. A smokable material as claimed in claim 1 in which the metal
chloride or metal sulfate is present in an amount within the range
of 5-25 percent by weight.
6. A smokable material as claimed in claim 1 in which the metal
chloride or metal sulfate is present in an amount within the range
of 8-15 percent by weight.
7. A smokable material as claimed in claim 1 in which the metal
chloride and sulfate is selected from the group consisting of
calcium chloride, magnesium chloride, calcium sulfate and magnesium
sulfate.
8. A smokable material as claimed in claim 1 in which the
flexibilizing and strengthening binder is present in an amount
within the range of 1-10 percent by weight.
9. A smokable material as claimed in claim 1 in which the binder is
a polyalkylene carbonate.
10. A smokable material as claimed in claim 1 in which the binder
is polyvinylene carbonate.
11. A smokable material as claimed in claim 1 in which the binder
is a cellulose derivative or a free acid thereof.
12. A smokable material as claimed in claim 1 in which the
cellulosic material subjected to thermal treatment has added
thereto a compound selected from the group consisting of starch,
sugar and dextrin, and mixtures thereof.
13. A smokable material as claimed in claim 12 in which the starch,
when present, is present in an amount within the range of 10-15
percent by weight, the sugar, when present, is present within the
range of 15-20 percent by weight, and the dextrin, when present, is
present in an amount within the range of 20-25 percent by
weight.
14. A smokable material as claimed in claim 1 which includes a
humectant in an amount up to 10 percent by weight.
15. A smokable material as claimed in claim 14 in which the
humectant is a compound selected from the group consisting of
glycerol, glycol, and a polyhydric alcohol.
16. A smokable material as claimed in claim 1 which includes a
coloring agent in combination with the thermally reacted cellulosic
material for converting the product to a rich brown color.
17. A smokable material as claimed in claim 16 in which the
coloring agent comprises the reaction product of a calcium ion with
triquinonyl.
18. A smokable material as claimed in claim 1 which includes an
organic amine in an amount sufficient to adjust the pH to at least
8.
19. A smokable material as claimed in claim 1 in which the burning
rate of the cellulosic material is controlled by the presence of an
alkaline earth metal salt of an anion selected from the group
consisting of sulfate and chloride.
20. A smokable material as claimed in claim 19 in which the burning
rate controlling alkaline earth metal salt is present in an amount
within the range of 0.5 to 5 percent by weight.
21. A smokable material as claimed in claim 1 which includes a
metal citrate in an amount within the range of 1-10 percent by
weight of the smokable material to improve the glow characteristics
during burning.
22. A smokable material as claimed in claim 1 which includes a
hydroxy acid or salt thereof to improve the ashing characteristics
of the smokable material.
23. A smokable material as claimed in claim 22 in which the hydroxy
acid is selected from the group consisting of oxalic acid, citric
acid, maleic acid and pivalic acid.
24. A smokable material as claimed in claim 22 in which the ashing
ingredient is present in an amount within the range of 1-10 percent
by weight of the smokable material.
25. A method for producing a smokable material comprising exposing
a cellulosic material loaded with 10-30 percent by weight of a
compound selected from the group consisting of the carbonate and
oxalate of an alkaline earth metal and 0.5-25 percent by weight of
a compound selected from the group consisting of a metal chloride
and a metal sulfate, to a temperature within the range of
275.degree.-500.degree.C, for a time sufficient to effect a weight
loss within the range of 40-75 percent of the cellulosic material,
maintaining non-oxidizing conditions during normal treatment,
treating the thermally degraded cellulosic material to incorporate
a flexibilizing and strenghtening agent in the form of a binder in
an amount within the range of 0.5-10 percent by weight, and then
processing the resulting thermally degraded cellulosic material to
the form desired for use as a smoking material.
26. The method as claimed in claim 25 in which the cellulosic
material is subjected to thermal treatment for a time sufficient to
effect a weight loss within the range of 50-60 percent.
27. The method as claimed in claim 25 in which the alkaline earth
metal compound is selected from the group consisting of the
carbonate and oxalate of calcium and magnesium and mixtures
thereof.
28. The method as claimed in claim 27 in which the alkaline earth
metal compound is present in an amount within the range of 15-25
percent by weight of the cellulosic material.
29. The method as claimed in claim 25 in which the metal chloride
or sulfate is selected from the group consisting of calcium
chloride, calcium sulfate, magnesium chloride and magnesium
sulfate.
30. The method as claimed in claim 29 in which the metal chloride
or sulfate is present in an amount within the range of 5-25 percent
by weight.
31. The method as claimed in claim 29 in which the metal chloride
or sulfate is present in an amount within the range of 8-15 percent
by weight.
32. The method as claimed in claim 25 in which the flexibilizing
and strengthening agent is present in an amount within the range of
1-10 percent by weight.
33. The method as claimed in claim 25 in which the flexibilizing
and strengthening agent is a binder selected from the group
consisting of a polyalkylene carbonate, a cellulose ethyl or ester,
or carboxymethyl cellulose, or a free acid derivative thereof.
34. The method as claimed in claim 25 in which the metal sulfate or
chloride is incorporated in the cellulosic material by wetting the
cellulosic material with a solution or dispersion of the sulfate or
chloride in a suitable liquid diluent and then drying the treated
product before subjecting the treated cellulosic material to
thermal degradation.
35. The method as claimed in claim 25 which includes the step of
treating the cellulosic material prior to degradation with a
solution or dispersion containing a compound selected from the
group consisting of starch, sugar, and dextrin, and mixtures
thereof.
36. The method as claimed in claim 35 in which the starch is
incorporated in an amount within the range of 10-20 percent by
weight, the sugar is incorporated in an amount within the range of
15-25 percent by weight, and the dextrin is incorporated in an
amount within the range of 20-30 percent by weight.
37. The method as claimed in claim 25 which includes the step of
washing the thermally degraded cellulosic material with water
following the thermal reaction step.
38. The method as claimed in claim 25 which includes the step of
adding a humectant to the thermally degraded cellulosic material in
an amount up to 10 percent by weight.
39. The method as claimed in claim 25 which includes the step of
adding an amine to the thermally degraded cellulosic material in an
amount to raise the pH to at least 8.
40. The method as claimed in claim 25 which includes the step of
adding a coloring agent to the thermally degraded cellulosic
material to impart a brown color thereto.
41. The method as claimed in claim 25 which includes the step of
mixing a cured natural tobacco with the thermally degraded
cellulosic material to form the smokable material.
42. The method as claimed in claim 25 which includes the step of
adding an alkaline earth metal salt of an anion selected from the
group consisting of sulfate and chloride to control the burning
rate of the cellulosic material.
43. The method as claimed in claim 42 in which the alkaline earth
metal salt for controlling the burning rate is present in an amount
within the range of 0.5-5 percent by weight
44. The method as claimed in claim 25 which includes the step of
adding to the thermally degraded cellulosic material a metal
citrate in an amount within the range of 1-10 percent by weight to
improve the glow characteristics during burning of the cellulosic
material.
45. The method as claimed in claim 25 which includes the step of
adding to the thermally degraded cellulosic material a hydroxy acid
or salt thereof in an amount within the range of 1-10 percent by
weight of the cellulosic material to improve the ashing
characteristics of the smokable material.
46. The method as claimed in claim 45 in which the hydroxy acid is
selected from the group consisting of oxalic acid, citric acid,
maleic acid and pivalic acid.
Description
This invention relates to a smokable material which can be used
alone or in admixture with conventional cured tobacco as a filler
for smoking in cigars, cigarettes or pipes and it relates further
to a method for the preparation of same.
It is an object of this invention to produce and to provide a
method for producing a smokable material of the type described
which is low in cost and formed of readily available materials;
which can be produced in a simple and efficient manner, batchwise
or in a continuous operation; which is low in tars and relatively
free of nicotine; which is low in polycyclics and carbonyls and is
thus characterized by good taste and aroma; which can be mixed in
wide proportions with cured tobacco without noticeable change in
the smoking characteristics of the resulting product; which has
strength, feel and mass integrity characteristic of conventionally
cured tobacco to enable processing with conventional equipment and
with conventional materials in the manufacture of cigars and
cigarettes, and in which there is little if any deviation in the
smoking characteristics, taste and aroma from conventional cured
tobacco.
Briefly described, in the manufacture of the improved smokable
material of this invention, a cellulosic material is subjected to
thermal treatment in the presence of alkaline earth metal salts
until the cellulosic material experiences a weight loss, due to
thermal degradation and the like, by an amount greater than 40
percent but preferably less than 75 percent, after which the
thermally treated cellulosic material is processed through washing
and compounding steps to a composition in form desirable for use as
a smoking material, as will hereinafter be described in greater
detail.
In the preferred practice of this invention, use is made of a sheet
or strip of cellulosic material, such as alpha-cellulose, in which
the cellulosic fibers are interfelted in the form of a sheet or
strip having sufficient mass integrity for processing through the
various steps hereinafter described, as a continuous,
semi-continuous or batch operation. Instead of alpha-cellulose, the
cellulosic material which may be employed in the practice of this
invention includes wood pulp, paper pulp, straw, flax, bamboo,
cotton, hemp, rice fibers, vegetable fibers, and the like, and
mixtures thereof. Instead of a cellulosic material of the type
described, use can be made of a cellulosic derivative such as
cellulose ethers or esters, represented by methylcellulose,
ethylcellulose, carboxymethylcellulose, or carbohydrate materials
such as starch, gum, alginates and the like, preferably reduced to
fiber or sheet form, all of which are collectively hereinafter
included within the term "cellulosic material."
When, as in the preferred practice of this invention, the
cellulosic material is employed as a starting material in the form
of a sheet or strip, it is desirable to make use of a sheet or
strip having a thickness within the range of 5-10 mm and preferably
within the range of 7-9 mm. Instead of making use of the cellulosic
material in the form of sheets or strips, the raw material used in
the manufacture of a smokable product of this invention can be
provided in the form of fibers or other discrete particles.
The cellulosic material which is subjected to thermal treatment, in
accordance with the practice of this invention, is formulated to
contain an alkaline earth metal salt formed preferably of calcium
and/or magnesium as the cation and oxalate or carbonate as the
anion, as represented by calcium carbonate, calcium oxalate,
magnesium carbonate and magnesium oxalate, and mixtures thereof.
The alkaline earth metal salt can be incorporated with the fibers
during fiber formation or during the formation of the fibrous sheet
or strip, or it can be incorporated, as by impregnation, into the
sheet or strip for uniform distribution after the sheet or strip
has been formed. In the alternative, it can be introduced by
formation of the salt in situ from the components thereof.
For example, when the salt is in the form of a calcium oxalate, the
calcium oxalate can be incorporated in the desired amount in
various ways. For most intimate and uniform distribution with the
cellulosic material, the calcium oxalate can be formed in situ in
the cellulosic material by first treating the cellulosic material
to load the material with the desired amount of calcium carbonate,
calcium oxide or other calcium salt, followed by treatment, as by
one or more impregnations, with a dilute solution of oxalic acid
which reacts with the calcium salt to form insoluble calcium
oxalate in situ in the cellulosic material.
Instead, the calcium oxalate, calcium carbonate, magnesium oxalate,
or magnesium carbonate, or other alkaline earth metal oxalate or
carbonate can be introduced into the header or otherwise admixed
with the cellulosic fibers for distribution with the pulp that is
passed over the Fourdrinier screen in the manufacture of paper or
strip thereof. The metal salt can be incorporated in less intimate
association with the cellulosic material, as by impregnation of the
cellulosic material with an aqueous medium containing the calcium
oxalate, calcium carbonate, magnesium oxalate or magmesium
carbonate in suspension in a suitable concentration. When use is
made of a cellulosic material other than in sheet form, the
alkaline earth metal salt can be admixed with the cellulosic
material in the form of a dry powder or aqueous suspension, and
then sheeted or dried for subsequent thermal treatment in the
manner hereinafter described.
The desired results are achieved when such alkaline earth metal
salts are present in an amount within the range of 10-30 percent by
weight of the cellulosic material and preferably in an amount
within the range of 15-25 percent. Instead of calcium and magnesium
oxalate or carbonate, use can be made of salts formed of calcium,
barium, magnesium, strontium, or the like alkaline earth metals as
the cation and anions such as the pivalate, glycolate and the like
polyhydroxy organic compounds.
Thermal degradation of the cellulosic material is benefitted
greatly from the standpoint of uniformity and character of the
degradation by the presence in the cellulosic material of an acid
salt preferably in the form of a sulfate and/or chloride of an
alkaline earth metal, preferably calcium and/or magnesium.
In the preferred practice of this invention, the chloride and/or
sulfate is provided on the cellulosic material subsequent to sheet
formation or incorporation of the carbonate and/or oxalate, so that
the chloride and/or sulfate will remain concentrated at the surface
of the cellulosic material during the subsequent thermal
treatment.
Application of the alkaline earth metal sulfate and/or chloride can
be made from solution in aqueous medium as by spraying onto the
dried cellulosic material prior to thermal treatment, or by
immersion of the dried sheet in the aqueous solution, or by mixing
the desired amount of solution with the cellulosic material,
depending somewhat upon the form of the cellulosic material which
is to be subjected to the thermal treatment.
It is believed that the sulfate and/or chloride functions as an
inhibitor to control the character of the thermal degradation of
the cellulosic material whereby a thermally treated product having
optimum strength and smoking characteristics is achieved. The
desired inhibitor effect can be secured with chlorides and/or
sulfates of other metal cations, such as of metals of the Groups I,
II, III and IV of the periodic table including sodium, potassium,
barium, aluminum, iron and the like.
The desired results are experienced when the chloride and/or
sulfate are present in an amount corresponding to 2 percent by
weight of the cellulosic material but for best results it is
desirable to make use of such chloride and/or sulfate in an amount
within the range of 5-25 percent by weight and preferably in an
amount within the range of 8-15 percent by weight of the cellulosic
material.
Thermal treatment of the described cellulosic material is carried
out in a non-oxidizing, preferably inert, atmosphere at a
temperature within the range of 275.degree.-500.degree.C and
preferably at a temperature within the range of
325.degree.-400.degree.C, for a time sufficient to effect a weight
loss of the cellulosic material in an amount of at least 40 percent
but less than 75 percent, and preferably in an amount within the
range of 50-60 percent. The time of exposure to degradation
temperature will depend somewhat upon the form in which the
cellulosic material is exposed and the temperature to which it is
exposed. For example, when the cellulosic material is in the form
of a sheet or strip having a thickness within the range of 7-9
mils, exposure for from 4-5 minutes at 350.degree.C will be
sufficient. Less time is required at higher temperatures and more
time at lower temperatures to achieve the corresponding amount of
degradation and more time will be required the greater the
thickness of the sheet or layer of cellulosic material exposed to
the elevated temperature for thermal treatment.
When in the form of a sheet or strip, thermal treatment can be
carried out as a continuous operation by passing the sheet
continuously through a space maintained inert by the passage of
nitrogen or other non-oxidizing gas therethrough and which is
heated to the desired temperature, with the rate of travel
coordinated with the length of the heated space to provide for the
time of exposure to elevated temperature sufficient to achieve the
desired degradation, as measured by weight loss of the cellulosic
material. When in a form other than an endless sheet or strip, the
cellulosic material can be subjected to thermal treatment in a
batch operation, or in a continuous operation when supported on a
suitable surface for continuous passage through the space heated to
the desired temperature.
As the inert atmosphere in which thermal treatment is carried out,
it is preferred to make use of nitrogen gas, although use can be
made of other inert, non-oxidizing gas, such as carbon dioxide,
helium and the like. The desired result can be achieved by heat
treatment of the cellulosic material, at the desired temperature,
in an enclosed chamber wherein the oxygen originally present in the
air entrapped within the chamber is quickly reduced to a level
wherein non-oxidizing conditions prevail to enable rapid heating of
the cellulosic material to effect the desired thermal degradation
in accordance with the practice of this invention. Instead, the
non-oxidizing atmosphere can be provided by effecting thermal
treatment of the cellulosic material in an enclosed space under
vacuum conditions.
After themal degradation it is desirable to subject the cellulosic
material to a water wash for removal of water soluble components
which remain in the thermally treated product. The desired wash can
be effected by flowing a stream of water, preferably warm water,
over the endless sheet or strip as it issues from the heat
treatment step. Instead, it can be washed by immersion in a water
bath, with or without agitation, for a time sufficient to effect
the desired cleansing action. If a water wash is employed, the
treated cellulosic material is dried before being subjected to
subsequent processing steps for incorporating various additives
with the thermally degraded cellulosic material prior to processing
to the form desired for use as a smokable product.
Marked increase in the strength and flexibility of the thermally
degraded cellulosic material can be achieved by the addition of an
organic binder component. For this purpose, use is preferably made
of a synthetic film forming polymeric material in the form of a
homopolymer (1) or copolymer (2) or vinyl carbonate derivative (3)
or hydroxy (4), or ketone derivative thereof. ##SPC1## in which
R.sub.1 and R.sub.2 may each be hydrogen, methyl, ethyl, propyl,
isopropyl, butyl, isobutyl, sec butyl, pentyl, isopentyl, hexyl,
nonyl, decyl or other alkyl group or mixtures of such hydrogen and
alkyl groups.
Such polymers of vinylene carbonate and derivatives thereof form
water insoluble plastic films or coatings and can therefore
function admirably as a binder or film former in the preparation of
reconstituted smokable products when combined with inert
non-combustible fillers and/or combustible materials of the types
previously described. The polymer (1) which consists of repeating
1,3-dioxolane-2-one ring system, in which the repeating units are
coupled at the C.sub.4 and C.sub.5 positions, respectively, is
capable of clean combustion to carbon dioxide and water, since all
carbon atoms in the ring system are bonded to oxygen atoms. The
linear polycarbonates should also burn in an analogous manner to
yield very little if any chemical irritants and carcinogens.
Polyvinylene carbonate can be produced by homopolymerization of
vinylene carbonate by the process described by M. S. Newman and R.
W. Addor, J. Am. Chem. Soc. 75, 1263 (1953). The polymethylol
derivative can be produced by hydrolysis of polyvinylene carbonate,
as described by Unruh and Smith, J. Org. Chem., 23, 625 (1958) and
the corresponding ketone should be produced by conventional
oxidation of the polymethylol.
Vinylene carbonate or derivatives thereof, copolymerized with
olefins, such as acrylic acid, alkyl acrylates such as methyl
acrylate or methyl methacrylate, or maleic acid or anhydride can be
used as the film former or binder in the same manner as the
polyvinylene carbonate, since such copolymers should also combust
with the production of very little, if any, noxious combustion
products in the smoke.
Treatment of the thermally degraded cellulosic material with
polyvinylene carbonate or other polyalkylene carbonate of the type
described provides a very strong and flexible sheet which burns
cleanly without introducing undesirable ordor or taste. The
thermally degraded sheet treated with the binder component is
relatively water resistant thereby to militate against leaching of
water soluble additives. As will hereinafter be described, the
polyvinylene carbonate serves as a vehicle for imparting the
desired tobacco color to the ultimate smokable material formed in
accordance with the practice of this invention and improves the
stability of the smokable material during storage and helps
maintain a desirable moisture balance therein.
Instead of a polyalkylene copolymer of the type described, the
binder component may comprise a cellulose derivative such as
methylcellulose or carboxymethylcellulose and preferably a
cellulose derivative of the type described from which the sodium
has been removed, as by ion exchange, to provide the free acid of
the corresponding cellulose derivative which is no longer water
soluble and, like the polyalkylene carbonates, imparts a desirable
degree of water resistance to the smokable thermally degraded
cellulosic material.
As the binder, use can also be made of a natural resin or gum, such
as gum tragacanth, guar gum, terpene resins and the like, which
impart strength and flexibility to the degraded fibrous structure
without giving off undesirable taste, odor, polycyclics, tars or
nicotine during smoking of the product.
Improvement in strength, flexibility and water resistance is
observed when the binder or polymeric component is present in an
amount of at least 0.5 percent by weight of the cellulosic material
but it is undesirable to make use of an amount greater than 10
percent by weight. In the preferred practice of the invention, the
smokable thermally degraded cellulosic material is treated to
incorporate one or more of the described binder components in an
amount within the range of 1-10 percent by weight.
The binder component can be applied as a coating onto the thermally
degraded cellulosic material from solvent solution or aqueous
dispersion. For example, when use is made of a polyalkylene
carbonate, application onto the sheet can be effected by spraying
from a solution in acetone to wet both sides of the sheet until the
desired amount of polymeric material has been incorporated. When
use is made of carboxymethyl cellulose, methyl cellulose, or other
water soluble gum or resin, application can be made from water
solution while the water insoluble free acid of the cellulose
derivative can be applied from solution in suitable solvents or
from an aqueous dispersion. The degraded cellulosic material can be
sprayed with the binder component when in sheet or other form or
else combined with the degraded cellulosic material for admixture
therewith in suitable mixing equipment for uniform
distribution.
The dried cellulosic material is now in condition for processing to
the forms desired for use as a smokable material. When in the form
of a sheet or strip, the processed cellulosic material can be
slitted into thin strips for twisting or intertwisting with other
strips to form strands which can be cut to lengths suitable for use
in filling machines for the fabrication of cigars, cigarettes or as
a pipe tobacco substitute. Such strips can be intertwisted one with
another to form a filler composed entirely of the synthesized
smokable material or they can be intertwisted with strands of
natural tobacco for admixture therewith in various proportions to
produce a smokable material.
When in the form of discrete particles, the cellulosic material can
be agglomerated into pellets or plugs cut to the desired shape and
size for use in the filler. As previously described, such discrete
particles can be blended in various proportions with cured natural
tobacco to form a mixture which has the appearance, aroma and taste
and which burns like natural tobacco when fabricated into a smoking
product.
Having described the basic concepts of this invention,
exemplification will now be made by way of the following examples
which are given by way of illustration, but not by way of
limitation.
EXAMPLE 1
A sheet formed of paper pulp having a thickness of 8 mils and
containing 20 percent by weight calcium carbonate, incorporated
into the pulp slurry for separation with the fibers on the screen
for uniform distribution with the fibers during fabrication of the
paper sheet, is spray coated with a 5 percent aqueous solution of
calcium chloride in an amount to dampen the paper and incorporate
about 5 percent by weight calcium chloride.
The sheet is advanced through a dryer and then through an oven
heated to a temperature of 350.degree.C and maintained inert by
circulation of nitrogen gas therethrough. The sheet is advanced
through the oven at a rate for exposure of 4-5 minutes at the
elevated temperature. Under these conditions, the cellulosic
material experiences a weight loss of 50-55 percent by weight while
still remaining in sheet form having strong mass integrity.
Upon issuance from the thermal treating oven, the thermally
degraded sheet is washed with warm water as by passing beneath
rollers submerged in a warm water bath, followed by drying in an
air circulating oven.
Thereafter, the processed sheet is spray coated on both sides with
a 10 percent solution in acetone of polyvinylene carbonate to
deposit 2 percent by weight of resin solids, based upon the weight
of the degraded cellulosic material. After drying, the sheet is cut
into strips, twisted into strands, and cut into pellets suitable
for use in filling machines for preparing cigars, cigarettes, or
for use as pipe tobacco.
By way of modification, the strips can be intertwisted with strips
of tobacco in an amount to make up 20-50 percent by weight of the
resulting intertwisted smokable material.
EXAMPLE 2
The procedure of Example 1 is followed except that the paper pulp
is replaced by alpha-cellulose containing 10% by weight calcium
carbonate and 15 percent by weight calcium oxalate.
EXAMPLE 3
The procedure of Example 1 is followed except that instead of the
polyvinylene carbonate, use is made of a corresponding amount of
carboxyethyl cellulose, methylcellulose, or free acid derivative
thereof.
By way of modification, an improved smokable material is produced
when, prior to thermal treatment to effect controlled degradation
of the cellulosic material and preferably before introduction of
the chloride or sulfate of the alkaline earth metal, the cellulosic
material is modified by the incorporation of starch, sugar or a
dextrin, and preferably a mixture thereof. Such materials can be
employed in rather wide proportions such as 1-20 percent by weight
and preferably 10-15 percent by weight of starch, 10-30 percent and
preferably 15-25 percent by weight sugar or other sucrose or
dextrose, and 20-40 percent and preferably 20-30 percent by weight
of dextrin. Such components or mixtures thereof in the amounts
described can be incorporated by spray or brush coating the
cellulosic sheet with an aqueous solution of the components or by
admixture with the cellulosic material from an aqueous solution or
dispersion, for uniform distribution with the cellulosic material.
After the incorporation of the starch, sugar and/or dextrin, the
cellulosic material is dried before being subjected to thermal
treatment.
EXAMPLE 4
The procedure of Example 1 is followed except that prior to coating
with the calcium chloride, the cellulosic sheet is first coated by
brushing to wet each side of the sheet with an aqueous medium
containing 2 percent by weight starch, 3 percent by weight cane
sugar and 4 percent by weight dextrin. Application is made in
amount to provide about 12 percent by weight starch, 18 percent by
weight sugar and 24 percent by weight dextrin based upon the weight
of the cellulosic material. The material is dried and then treated
with the solution of calcium chloride as described in Example
1.
The resulting thermally degraded product is characterized by
improved strength by comparison with cellulosic material thermally
degraded under the same conditions but without the added sugar,
starch and dextrin.
Various other additives can be incorporated with the thermally
degraded cellulosic material of this invention to provide desirable
improvements in processing characteristics and to improve color,
taste, feel and aroma.
Addition can be made of a humectant to keep the smoking material
moist and pliable and to enhance the packing characteristics as
well as the burning characteristics of the product. For this
purpose, use can be made of a polyhydric alcohol, such as glycerol
or a glycol, represented by ethylene glycol, propylene glycol and
the like, inositol, butane diol and the like hygroscopic materials
and mixtures thereof. These materials can be applied by spraying
from water solution onto the sheet or particulates, or by admixture
with the treated cellulosic or carbohydrate material. Addition is
made in amounts up to 10 percent by weight and preferably within
the range of 1-4 percent by weight, when added.
The glow and ashing characteristics of the smoking material can be
improved by the addition of water soluble alkali metal salts, such
as sodium or potassium salts of low molecular weight hydroxy acids,
such as oxalic, citric, maleic, pivalic and the like organic acids,
or carbonates, bicarbonates or phosphates, such as potassium
citrate, sodium citrate, potassium bicarbonate, potassium maleate
and dihydrogen sodium phosphate, and mixtures thereof. In addition,
the hydroxy acids, such as oxalic, citric, maleic and pivalic and
the like organic acids may be used. Such mineralizing agents or
ashing ingredients, when employed, may be incorporated in amounts
up to 30 percent by weight of the smokable material and preferably
in an amount within the range of 1-10 percent by weight.
Modification of the thermally degraded cellulosic material by the
incorporation of an alkaline earth metal (calcium, magnesium,
barium, strontium, etc.) salt of a chloride or sulphate enhances
the burning characteristics of the resulting smokable material by
control and uniformity of burning rate. Such alkaline earth metal
sulphates or chlorides can be incorporated from solution or
dispersion, as by spraying to wet the cellulosic material or by
admixture of the salts with the cellulosic material in solution,
dispersion or dry powder form. Improved burning characteristics and
control is experienced when the alkaline earth metal sulphate
and/or chloride is present in an amount up to 10 percent by weight
but it is preferred, when present, to make use of an amount within
the range of 0.5-5 percent by weight of the cellulosic
material.
From the standpoint of appearance, it is desirable for the smoking
material to having a dark brownish color, corresponding to that of
rich cured tobacco. The dark gray material resulting from the
thermal treatment of this invention is not readily colored by
conventional dyestuffs unless employed in undesirable enormous
amounts. It has been found that novel use, as a coloring material,
can be made of triquinonyl C.sub.6 O.sub.6.8H.sub.2 O, which
produces a strong orange to brown color with calcium or magnesium
present in the cellulosic or carbohydrate product thereby to
provide a non-leachable color that is effective to convert the
thermally treated product to a rich brown color.
Flavor and aroma can be improved by the addition of flavoring
agents, such as nicotine, menthol, chlorogenic, caffeic and guinic
acids, essential oils, tobacco extracts and the like.
It will be understood that changes may be made in the details of
formulation and operation without departing from the spirit of the
invention, especially as defined in the following claims.
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