NO752429L - - Google Patents

Description

This invention relates to smoking mixtures and more particularly to smoking mixtures containing natural or synthetic swelling agents. Clay types.." In the following, the term "smectite<H> is used for natural or synthetic swelling clay. This use of the term includes raontmorillonite, beidellite, nontronite, saponite, hectorite and anukonltt. Montmorillonite is the main constituent of bentonite clays. which have exceptionally good water absorption and cation exchange properties.

Natural bentonite is a clay mineral consisting mainly of montmorillonite. a complex alurainiuarsilicate. This is naturally associated with kfetions. mainly calcium ions, but also some sodium ions. Treatment of natural bentonite can change the relative amounts of the associated cations or introduce new cations, but the treated products, as well as the naturally occurring ones, are collectively referred to as bontonites. Examples can be shown to calcium bentonites. meaning bentonites in* which the associated cations are predominantly, but not exclusively, calcium and sodium bentonites. meaning bentonites in which such ions are predominantly, but not exclusively, sodium.

Sraectites in their original form are aggregates of very small particles. In particular, X-ray investigations have shown that the elementary unit layer of montmorillonite consists of three layers and an octahedral layer of hydrargillite-brucite between two tetrahedral layers of silicon and oxygen. Exchangeable cations occur between silicon=5 layers. Consequently, the properties of bentonites, as well as the properties of all smectites, are highly influenced by the associated ones

exchange cations nature.

It is known to incorporate smectites, especially bentonites, into manufactured smoking materials - for example smoking materials in the form of films or other forms of which tobacco-simulating material

can be produced, but until now this mixing has been carried out by slurrying solid smectite and all the other ingredients in water at normal temperatures; after which the slurry is formed into, for example, a film. With this known technique, the smectite in the produced smoke has been very finely dispersed, although some smectites actually disperse quite well in water, compared to others, for example, sodium bentonites are easier to disperse than calcium bentonites.

The degree of disaggregation when smectite is slurried in water increases with the energy input. Under normal conditions including rapid stirring, a point is reached where the viscosity reaches a maximum value. In the following, the expression "finely dispersed smectite" shall mean a smectite in as fine a dispersion as that which is obtained by dispersing it in water at 15°c under a supply of *v 0.04 and preferably 0.08 joules/g/sec. until a maximum viscosity is reached. The invention provides a manufactured smoking material comprising a film-forming binder, inorganic filler and a smectite, which smectite is finely dispersed in the smoking material.

Essential ingredients in the smoking materials according to the invention are the film-forming binder, inorganic filler or additive and smectite. but other ingredients can also be mixed in, especially plastic and combustible material. Additional ingredients that can be used are, for example, moisture-binding agents such as glyceroi. glycol is» glow-regulating catalysts such as potassium citrate<p>ts colored flavoring or flavoring agent and nicotine,

Cellulose ethers can be used as film-forming binders, for example methyl cellulose and especially carboxymethyl cellulose and salts thereof. Pectins, starch, binders or natural rubbers are other examples of film-forming binders that can be used.

If desired, the film-forming binder can be used

in such amounts rt it essentially constitutes all of the combustible material or fuel in the smoking material. Preferably, however, a non-binding fuel is also used, especially a particulate fuel, and the binder's main function is then to

ensure that all the ingredients work sufficiently well for the production of the material.

Particulate fuels that can be used include tobacco powder? carbohydrates, especially cellulose* and especially modified carbohydrates, that is to say here carbohydrates which have been subjected to a treatment that modifies one or more chemical properties.

The modified carbohydrate that can be used is suitably a thermally degraded carbohydrate, in particular thermally degraded cellulose, for example produced as described in British patent no. 1 113 979 by subjecting the carbohydrate to a catalyzed degradation process at a temperature of 100°->50° C until the weight of the built-up material is less than 90% of the dry weight of the soluble carbohydrate.

The modified carbohydrate that can be used. can also be a first condensate produced by acid- or base-catalyzed condensation of a compound with the formula

(or a precursor thereof) , where R and R , which may be the same or different, represent a hydrogen atom or an alkyl, hydroxyalkyl or formyl group. Such capacitors in manufactured form are described in British patent no. 1 ?98 354.

A further example of a modified carbohydrate that can be used is oxidized cellulose, for example, prepared as described by Kenyon et al ("Industrlal and Engineering Chemistry<1">. volume 41, page 2 et seq.).

Smoke materials according to the invention containing large proportions, for example from 40 to 65% by weight, of inorganic filler are of particular value. Such high proportions have a beneficial effect when it comes to reducing the amount of harmful smoke components for the smoker. With a suitable choice of the inorganic compounds used, smoke mixtures containing 40-65% filler can be given an appropriate combustion rate. as described in British patent no. 1 799 990 In particular the anions in the filler can be citrate. formate, oxalpht. tartrate. silicate, carbon-t. oxide, chloride, sulphate, phosphate or boron. The cations may in particular be sodium, potassium, calcium, magnesium, iron or titanium.. Preferred . fillers are magnesium carbonate, basic magnesium carbonate, potassium sulphate. calcium phosphate, sodium borate, sodium chloride, sodium ortho-phosphate. calcium oxalate, iron sulfate, titanium dioxide. aluminum oxide and especially calcium carbonate.

Below are typical proportions of the most important ingredients in the smoke esters according to the invention.

However, the invention is not limited to such quantitative ratios.

Smoke mixtures produced according to the method according to the invention are advantageous compared to corresponding mixtures in which smectite is mixed in a different way without being finely dispersed.

Cigarettes containing the smoking materials according to the invention provide a more coherent smoke than cigarettes containing the aforementioned corresponding mixtures.

This is a discovery of great importance in the development of satisfactory tobacco substitutes, because the use of large proportions of filler, although beneficial from a health point of view, leads to the formation of fleck-like. non-cohesive ash that is clearly different from tobacco ash. This softness of the ash is noticeable to the smoker even when the tobacco substitute is mixed with relatively large amounts of tobacco.

A further advantage of the smoking materials according to the invention lies in the bentonite's relatively good flame-retardant properties when it is mixed in dispersed form. It is therefore possible to avoid or use as little as possible of other flame retardants: many of these have undesirable effects on the smoke. In particular, magnesium carbonate, a known flame retardant, causes the formation of carbon monoxide.

When an inorganic carbonate, especially calcium or magnesium carbonate, is a component of the inorganic filler, it is particularly desirable that its surface area is not greater than 0.6 m<*>/g,

especially from 0.2 to 0.3 m 'g, bssert on the material in a dry state.

In this way, the relative amount of other flame retardants is known

agents other than bentonite are reduced further.

A particularly preferred smoking material according to the invention has the following final composition: r

The invention further provides a method for producing a smoking material from ingredients comprising

a filler-forming binder, an inorganic filler, and a smectite, which method consists in mixing said ingredients with water, adding sufficient energy during the mixing operation to effect dispersion of the smectite in the resulting aqueous slurry, and converting the resulting slurry into a form suitable for manufacture©v tobacco-simulating material.., ■ \ " _ • _ '

In a first embodiment of the method according to the invention, the smectite is mixed into water under such a large energy supply that the viscosity of the slurry is not less than the viscosity of a slurry produced by mixing the same smectite and water at 15°C and supplying 0, 04, preferably 0.08 joules^/sec.. until a maximum viscosity is reached, after which the slurry is combined with the remaining ingredients, and the resulting slurry is converted into a form suitable for the manufacture of tobacco simulating material.

In this embodiment of the method, the smectite is dispersed separately in water by agitation, preferably under sufficient energy supply to increase the slurry's viscosity to the already specified value. unite with the d in spe rger rte smekt itt. After successive mixing to achieve homogeneity, the slurry is then converted into, for example, filaments, ribbons or sheets. Preferably, it is cast into a thin film and dried into a sheet. Alternatively, a thick slurry may be extruded into filaments, ribbons or sheets.As a further alternative, a papermaking process may be used. The sheet, filament or ribbon can then be unraveled or cut into a shape simulating tobacco,

Smoke materials which are produced in accordance with the above-mentioned form of the present method have a more coherent and less porous structure than corresponding materials where smectite is mixed in a known manner. Films of such materials are therefore characterized by lower air porosity (a parameter that can be measured as described below in the introduction to the examples,

The air porosity (measured as described below) of a film of smoking material according to the invention with a thickness of 0.05-0.2 mm should suitably be less than 1000 ral/min., preferably less than 500 ml</>min.

Another embodiment of the method according to the invention involves stirring the smectite together with other ingredients to be included in the smoking material, at a temperature above 50°C, so that the smectite is dispersed in the slurry. after which the resulting slurry is processed into a tobacco-simulating form.'■■ y

Smoke materials produced according to the latter embodiment exhibit porosities which, although lower than those obtained with corresponding materials produced in a known manner, are as a rule higher than the porosity of corresponding materials f «•me.ti.lt in the first embodiment.. Nevertheless, they are advantageous , in l.\£et with the materials produced according to the first embodiment, in that they provide a more cohesive = spoon than the known materials, and in that the bentonite's flame-retardant effect is increased when the bentonite is mixed in in this way.

The invention is further illustrated by the following examples, where parts and percentages are by weight.

The commercially available smectites that were used

in the examples, v<p>r as follows

Berkonite - essentially a calcium bentonite, although a sodium carbonate treatment is included in the production from naturally occurring material.

Aftuagel - a naturally occurring sodium bentonite from OSA.

Fulbent 570 - a sodium bentonite which is produced by sodium hydroxide treatment «v a natural calcium bentonite.

B erkbent CE - a sodium bentonite produced by sodium

kaleiuiribentonite,

';L*ponlte<w>(trademark) a synthetic hook or itt product.

In all the examples, unraveled smoke mixtures were 50/50 mixtures with unraveled tobnkkk. used for the production of lål g cigarettes with a length of 70mm and a circumference of 25 ram. The cigarettes were smoked in a specific smoking machine which per minute takes 35 ml puffs of 2 seconds. The number of puffs was noted, each cigarette being smoked down to a stub length of 20 mm.

Ash consistency is measured by weighing on a microbalance the cylinder of ash that first falls from the cigarette after smoking in a draft-free and vibration-free room. The entire amount of ash formed by smoking a whole cigarette was also weighed, and the average ratio between the weight of the first falling cylinder and the total weight of the ash is referred to here as the ash cohesion value.

Air porosities were measured using a Bendtsen Mark VI porosity meter. an instrument with which one can measure the observed airflow through a film at a given pressure. The indicated porosity values were measured at an air pressure of 75 mm of water using a 5 cm<1>' measuring head and are expressed in ml/min.

The thermally degraded cellulose used in several of the examples was produced by impregnating the cellulose with a 7% ammonium sulphate solution, after which the cellulose was pressed until it contained a single weight of the solution, after which it was dried at 165°C and heat treated at 265°C until the weight loss was 25-305É.

EXAMPLES 1-3

The bentonites indicated in Table I were dispersed by stirring 5 parts into 95 parts of water in a recirculation mill (a PUC mill in position 3) at 45-50°C until a constant viscosity was achieved.

Smoke materials were prepared by slurrying the following ingredients in water, the bentonites being mixed in and dispersed as in the previous section, and the slurry was cast on a belt dryer, whereby a film was obtained which on a dry basis weighed 48-52 g/m 2 ; the film was dried and unraveled. This material was mixed in a 50:50 ratio with shredded tobacco.

Cigarettes produced from the mixtures and from comparison mixtures are ho3ct by mixing dry bentonite into the slurries, and the results of the smoking tests are given in Table 1, which also includes determinations of air porosity in the films.

Examples 4 and 5

Dispersion of the bentonites listed in the table was carried out by stirring 5 parts in 95 parts water at 45-50°C using a turbine-type stirrer with low shear (energy input 0.007 joules/g/sec.) until a maximum viscosity had been achieved.

Smoke mixtures were prepared by slurrying the following ingredients in water, mixing in the bentonites dispersed as in the previous section, after which the slurry was cast on a belt dried to a film that weighed on a dry weight basis. 48-52 g/m . The film thus obtained was dried and unraveled.

This material was mixed with shredded tobacco in a ratio of 50:50.

The experiments with the cigarettes of these mixtures, as well as the air porosity of the films, are indicated in Table II.

Examples 6-10

In these examples, the bentonites indicated in Table III were dispersed in slurries of the other ingredients in the tobacco mixture by stirring at 55-65°C. The slurries were pressed on a belt dryer to a film which on a dry weight basis weighed 48-50 g/m<2> and the film was dried and unraveled.

The composition of these films was:

Two series of films were presented

(a) using coarse calcium and magnesium carbonates with an average surface area of 0.25 ra<2>/g determined by the air permeability method of P.J. Rigden in Journal of the Society of Chemical Industry, 1943, pages 1-4. (b) using commonly available finely divided calcium and magnesium carbonate with an average surface area of 0.87 m<2>/g. 50:50 mixtures of the unraveled films and tobacco were rolled into cigarettes and the test conducted as above. The test results are indicated in Table III.

Example 11

A smoking material was prepared by the following ingredients being slurried in water at 65°c and cast into a film which was then dried.

For comparison, a smoking material with the same composition was produced by slurrying at 28°c. Furthermore, similar materials were produced without Berkbent CE, the proportions of calcium and magnesium carbonate being adjusted so that the ratio between calcium and magnesium was kept constant.

. Each unraveled film was mixed with tobacco in a ratio of 50:50, and cigarettes made from the mixture were tested as indicated above. The test results are given in Table IV.

Example 12

A smoking material was prepared by slurrying the following ingredients at 60°C and casting into a fiflna, which was dried.

For comparison, a smoking material with the same composition was produced by slurrying at 28°C.

Each unraveled film was mixed with tobacco in a 50:50 ratio, and cigarettes made from the mixture were tested as indicated above. Smoking tests were also carried out with cigarettes made from unraveled film alone (100%). The results are shown in Table V.

Example 13

A smoking material was prepared by slurping the ingredients below in water at 60°c and casting into a film, which was dried.

Parts

Perlite (Celite PPl) 28 Berkbent CE 8

For comparison, a smoking material with the same composition was produced by slurrying at 28°c.

Each unraveled film was mixed with tobacco in a 50:50 ratio, and cigarettes made from the mixture were tested as indicated above. Smoking trials were also carried out with cigarettes made from 100% unraveled film. The results are shown in Table VI.

Example 14

A smoking material was prepared by slurrying the following ingredients in water at 60°C, casting into a film and drying.

For comparison, a smoke mixture with the same composition was produced by slurrying at 28°c.

Each unraveled film was mixed with tobacco in a 50:50 ratio, and cigarettes made from the mixture were tested as indicated above. The results are given in Table VII.

Example 15

An aqueous dispersion was prepared by vigorously stirring 3 parts Laponite in 97 parts water at 45-50°C until constant viscosity was achieved.

A smoke material was prepared by slurrying the below ingredients in water, Laponite being added as a dispersion, and the slurry was cast into a film on a belt-dried.

For comparison, a smoke mixture with the same composition was prepared where the aforementioned Laponite was added to the slurry as a dry powder.

Each unraveled film was mixed with tobacco in a ratio of 50x50 and the cigarettes made from the mixture were tested as indicated above. Smoking tests were also carried out with cigarettes made from 100% unraveled film, the results are given in table VIII

Claims (25)

1. Manufactured smoking material, characterized in that it consists of a film-forming binder, inorganic filler and a smectite, where the smectite is finely dispersed in the smoking material. 2. Smoke material according to claim 1, characterized by an air porosity which is significantly smaller than the air porosity in a corresponding material containing a smectite which is also finely dispersed. 3. Smoking material according to claim 1 in the form of one film, characterized in that the thickness of the film is 0.05-0.2 mm, the air porosity less than 1000 ral/min. measured at an air pressure of 75 mm of water using a 5 cm <2> mälehoffié© 4., Smoking material according to one of the preceding claims, characterized in that the film-forming binder constitutes essentially the entire combustible material. 5. Smoking material according to any one of claims 1*3, characterized in that it also contains a non-binding fuel. 6. Smoking material according to claim 5, can be of an active type in that the fuel is particulate. 7. Smoking material according to claim /6, characterized in that the particulate fuel is a thermally degraded carbohydrate. 8. Smoking material according to claim 6, characterized in that the particulate fuel is thermally degraded cellulose. 9. Smoking material according to one of the preceding claims, characterized in that the film-forming binder is sodium carboxymethyl cellulose. 10. Smoking material according to any of the preceding claims, characterized in that it contains 40-65% by weight inorganic filler. 11. Smoking material according to any one of the preceding claims, characterized in that it consists of 10-50% by weight film-forming binder, 0-30% by weight particulate fuel, 40-65% by weight inorganic filler, 3-10% smectite and 0r 20 % of other ingredients such as humectants and aromatics. 12. Smoking material according to claim 11, characterized in that it contains 3-7% by weight of smectite. 13. Smoking material according to one of the preceding claims, characterized in that the smectite is a bentonite. 14. Smoking material according to one of the preceding claims, characterized in that the inorganic filler includes an inorganic carbonate in coarse form, with a surface area not greater than 0.6 m <2> /g in the dry state. 15. Smoking material according to claim 14, characterized in that the inorganic carbonate is calcium or magnesium carbonate. 16. Smoking material according to claim 14 or 15, characterized in that the carbonate has a surface area of 0.2-0.3m<2>/g. 17. Smoking material according to any one of claims 1-3, characterized in that it consists of 10-20% by weight film] » forming binder, 20-30% by weight particulate fuel, 40-50% by weight inorganic filler including calcium carbonate in a coarse form with a surface area of 0.05-0.6 m 2 /g in the dry state, 3-7% by weight of dispersed sodium bentonite and 0-^10% soothing ingredients such as moisture-binding agents and aroma substances. 18. Smoking material according to claim 1 mainly as described in the examples. 19. Process for producing a smoking material according to claim 1 from ingredients comprising film-forming binder, inorganic filler and a smectite, characterized by mixing the mentioned ingredients with water, to- applies sufficient energy during the mixing operation to effect dispersion of the smectite in the resulting aqueous slurry, and works the resulting slurry into a form from which tobacco simulant material is obtained. 20. Method according to claim 19, characterized in that the smectite is dispersed separately in water before the union with the other ingredients by agitation to a slurry with a viscosity that is not lower than the viscosity of a slurry produced from the same smectite and water by agitation at 15° G with an energy input of 0.04 joule/g/second until a maximum viscosity is reached. 21. Method according to claim 20, Jsa rect ri black in that the viscosity of the smectite slurry is not lower than the viscosity of a slurry produced from the same smectite and water when agitated at 15°c with an energy input of 0.08 joule/g/second up to a maximum viscosity is achieved. 22. Method according to claim 19, characterized in that the smectite and other ingredients are slurried in water at a temperature above 50°C, whereby the smectite is dispersed in the slurry. 23. - Method according to any one of claims 19-22, characterized in that the smectite is a bentonite. 24. Method according to claim 19, mainly as described in the examples. 25. Smoke mat vials produced by the method according to any one of claims 19-22.