DE1517297B1 - Smoke filters for tobacco products - Google Patents

Description

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The invention relates to a smoke filter for tobacco water. Collision of the droplets with the fibers, they remain ren with a filter space through which the smoke can flow due to the surface adhesion between men and the an active absorbent granulate the extremely small particles and the relatively large with a specific surface area of more than 1,000,000 cm ² / g fibers. These filter granules made of fibers and having a particle size between 2.38 and 5 are not particularly effective, however, at about 0.30 mm. components from the smoke through the

As is well known, tobacco smoke consists of physical and chemical adsorption into a gaseous or vapor phase that removes liquids. The smooth and non-porous structure of the usual or semi-liquid droplets or solid particles typically used are suspended fibrous filter materials that form the visible smoke, while effective to remove droplets from the tobacco (these suspended particles are subsequently all-smoke it creates but none of them are commonly referred to as "droplets"). Commercially available large surface area to effectively remove gaseous molecules from cigarette filters, which are made up of a bundle of cellulose. It has been calculated that an ordinary fiber or a cylindrical plug, rather a filter stopper for cigarettes, consists of cellulose acetate wrapped crepe paper, is designed so that it has a surface in the range of 1000 to 10,000 cm ^a / g that it allows different proportions of this through the filter of the material. This surface is insufficient, remove droplets passed through. They keep to adsorb gaseous molecules effectively. In addition, this surface does not have any significant components that are soluble in cellulose acetate. Dar selectivity. In some cases in which vaporization follows from the gaseous or vapor phase of normal or gasified material being sufficiently soluble in the sometimes essentially unaffected by a fiber material so that its surface concentration flows through such a filter. tration decreases rapidly, a significant elimination

In the vapor phase of smoke, which is obtained from tobacco and gung through the absorption process. other natural leaf materials is obtained. An example of such a gasifiable material, which is different and generally small amounts 25 in the tobacco smoke, is phenol, which is one of the acidic, gaseous compounds cyanide - pronounced solubility in a filter material consisting of substance and hydrogen sulfide that has a cellulose acetate. Cellulose acetate filters allow specific toxic effects on the human genes to exert both hydrogen cyanide and hydrogen sulphide tissue with which they come into contact. If it happens in undesirably high concentrations, it has been found that these materials contribute to 3 ° Attempts have been made to reduce the adsorption properties of the action of the cone-shaped appendages or cells of tobacco smoke filters by different treatments of so-called cilia, which cover the trachea and the genes of ordinary filter material, by making bronchi line, inhibit. These cells of new fibrous filter materials and by beat rhythmically back and forth and thus promote the adsorbent additives to improve. Among the-foreign substances from the respiratory tract. It has been found 35 sen materials and treatments that suggested that the toxic materials mentioned are the well-known adsorptive impact or the flicker of the cilia in for it tion means, such as. B. activated carbon, aluminum oxide, selected test organisms and in natural and synthetic clays and silica gel, which prevent higher concentrations. It must be suggested as additives to tobacco smoke filters that a similar impairment 40 den. These materials are referred to as adsorbents also takes place in the human organism, so that the presence of these toxic materials in the presence of these toxic materials in the treatment of gas flows, as they have the common property of tobacco smoke, the capacity of the human lungs, that their specific surface area is greater than that of the sit Removal of unwanted foreign ^{matter is 1000,000 cm 2} / g of the material. A gas substance affects. 45 adsorbents of excellent quality, both

Hydrogen cyanide and hydrogen sulfide, for example, have activated carbon, have a specific surface area of over 5,000,000 cm ² / g at room temperature and above. Before-vapor pressure. They can be referred to as gases or highly volatile added procedural measures that were previously applied to liquids. In the case of imperfections, these adsorbents were burned in smoke filters, as they are e.g. B. in cigarettes, pipes and 5 °, consist in the fact that fiber material, which takes place in cigars, they are freed from the tobacco, the filter or a part of it forms, to dust or in a completely vaporous state to spray, in synthesized to the adsorbent. During the short period of time in which to circulate, coat them with a slurry from the combustion zone to the mouth of the Rau- or otherwise the finely divided adsorption shear, there is little opportunity for medium to introduce these volatile materials into the fibrous material For various reasons, these adsorption conditions are to condense and form solid droplets, medium-containing filters for tobacco smoke only produce the visible smoke. These materials are partially effective. One of these reasons is, therefore, almost entirely in vapor form, that the adsorbent was often in front of it when it was introduced, when it left the tobacco product and entered the carrier material and then during the treatment of the smoker's mouth. during cigarette manufacture and distribution

The commonly used commercial cigarette is ineffective because water, plasticizers, glue filters remove some of the varieties, adhesives and volatile aromatic substances from tobacco smoke, Droplets that are passed through the filter stay in close contact with the finely divided one for longer the. This is made up of a combination of adsorbents, partly or completely When the droplets come into contact with the filter fibers, they use up the adsorbing surface and so the due to the diffusion, the collisions of the droplets under- capacity to adsorb the gas molecules from the each other and with the fibers is given directly. Reduce after smoke.

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Other reasons are that when the other temperatures from the decomposition products

sorbents and the fibrous filter materials of amino acids, proteins and similar materials

are intimately mixed, condensed droplets are formed.

tend to settle in this filter at or near a further, it is known to precipitate adsorbent particles in the end to be lit, thereby quickly introducing cellulose from cigarette rods containing ferric sulfate and ethylene, relatively non-volatile smoke components. In the glow cone penetrate adsorbents and in this way the cigarette the ferric sulfate is decomposed to SO ₃ and iron whose adsorption capacity for gaseous molecules oxide and is reduced by the reaction of SO ₃ with. Nicotine decreases the nicotine content of smoke.

Further disadvantages of known adsorption- ίο However, this makes the cigarette smoke acidic, which can be seen in the fact that it is considerably undesirable, and the SO ₃ in the smoke has a toxic effect; Finally, it is already known to increase the taste of the smoke, filter substances with sulfuric acid or zinc chloride are too much changed. A powdery or finely divided 15 impregnate to reduce the nicotine content of the smoke to adsorbent, which is in a matrix of fiber. These measures have been dispersed when the shaped filter elements are not effective in preventing the filtering of cigarette smoke. Smoke flow through the filter and requires that the smoke filter for tobacco smokers exerts an additional suction effect around the goods with a filter material, the normal amount of smoke from the tobacco product to remove from the tobacco smoke. If there is enough adsorbent in the compounds hydrogen cyanide and sulphurous water filter to extract considerable amounts of pollutant and at the same time remove all components, the flow of smoke is effective the taste resisted well above a desirable and neither left unaffected or improved, pleasant level. 25 This filter is intended to be used on either cigarettes or cigars

On the other hand, it has been found that an arrangement of the adsorbent cigarette holders added to or separated as a separate filter cartridge for pipes and fibers is used in a part of the filter. This object is achieved by the invention in that it has an effect on the taste of the smoke. Adsorbent granules with finely divided iron and zinc oxides, if adsorbents, for example charcoal, are impregnated, each oxide in an amount of aluminum oxide or silica gel, in a Zi- of not less than about 1% and not more than a garette filter in sufficient amounts about 13 ° / ₀ , based on the weight of the adsorbent, to reduce the gaseous materials considerably to the granules and reduce the content of the two, it has been found that (when the adsorbent together 14% by weight of the granulator is separated from the cellulose acetate filter) 35 does not exceed.

the smoke taste of the smoker no longer The filter according to this invention can between is perceived as pleasant. Although some irritation-usual filter stoppers made of cellulose acetate or creping factors could be reduced, the smoke paper has to be used in a cigarette. Alternatively an astringent, bitter, dry taste. can filter for use in the shafts of Other mineral adsorbents have a pipe or cigarette holder shaped like a tube Overall effect with minor modifications chens with corresponding end plugs made of perforated the taste and aroma depending on paper, plastic metal or the like, the particular related agent. The general preference is one of the two oxides in one The result can be seen that a pleasant amount between about 4 and about 6 percent by weight, Smoke is obtained only when the amount of Ad- 45 based on the weight of the adsorbent, sorbent is so small that it is only mixed in with one. In other words, the filter material proportionate proportion of the filter compared to that is with about 1 to 13 percent by weight of an oxide that fibrous filter media. If it is one of those from the group, the iron oxides and zinc oxide reduce Amount is present, its effect is sufficient, is chosen and with at least 1% of the other visible removal of unwanted smoke constituents (not selected) from this group not from. is gnated, these oxides in finely divided form

There is already known a filter material in which to be used and put together in an amount

Metal oxides are present in a highly hygroscopic material, which is 14 percent by weight of the adsorbent

are distributed. This well-known filter that through granules do not exceed. Preferably that is

Traces of water are already poisoned, 55 filter material converts with between about 4 and 6% of the ge

Carbon monoxide into carbon dioxide. For one chose Oxyds impregnated.

The well-known material is suitable for cigarette filters

not because it is caused by moisture absorption from the adsorbent material, e.g. B. activated carbon, either

Tobacco, which contains about 12% moisture, immediately before or after sieving on the appropriate

would be destroyed. 60 particle size in an aqueous mixed solution

It is also known tobacco calcium oxide or from (a) a substance from the group consisting of

To add iron oxide to the pyrolytic processes zinc carbonate, zinc oxide and zinc acetate, (b) one

to modify in tobacco burning. One such substance from the group consisting of ferriammo-

Modification of tobacco combustion products nium citrate, ferric citrate, ferrocitrate, ferroammonium

has no filtering effect. In particular, 65 have citrate, ferroacetate and ferroammonium carbonate, and

the known additives to tobacco do not affect the (c) ammonia, a preferred mixture consists of

Formation of hydrogen cyanide in the cigarette, as the cyanide zinc carbonate, ferriammonium citrate and ammonia,

Soaked in hydrogen for the most part at significantly less - about 5 to 20 minutes and then that

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Wet adsorbent material remains under such conditions of solution, is a mixture of ferrous conditions is heated long enough that the adsor- ferrous ferric and ferric oxides, the lower values of salts, decompose to the corresponding metal oxides by reduction of the original oxidation states and the released ammonia, ferric ions are expelled by the carbon adsorbent carbon dioxide and other gases, 5 will hold. This mixture of iron oxides without the adsorbent material being oxidized. is referred to as "iron oxide" in this specification and the relative amounts of ingredients (a) and (b) claims. It has been found that these are selected, in relation to the desired ratio of degradation, essentially after an hour of zinc and iron oxides, which are to be precipitated on or longer heating at temperatures between adsorbents. io 175 and 350 ° C. in a sufficient air flow that carries away the various adsorbing substances for the gaseous degradation products, impregnation has been carried out for the purpose according to the invention. Complete removal of these gaseous forms is suitable. Examples of this are activated carbon, aluminum decomposition products is achieved when the carbon oxide, natural and synthetic clays and silica are heated to temperatures between 300 and 500 ⁰ C in an acid gel, each of which has a specific surface area of 15 inert atmosphere heated for more than 45 minutes which exceeds 1,000,000 cm ^a / g. That is loaded. Water vapor, nitrogen and carbon dioxide preferred adsorbent is a highly compressed one has proven to be effective inert gases for this purpose, activated charcoal with good mechanical strength. Other salts of the

This material has a specific surface area of desired metals instead of zinc carbonate and over 5,000,000 cm ² / g. Suitable coals for this 20 ferriammonium citrate can be used. Example purposes are obtained from nutshells or can wise zinc carbonate can be made from zinc oxide or zinc from bituminous coal. acetate to be replaced. Ferric ammonium citrate can be replaced in the adsorbent, which bark in a tobacco smoke - satisfactory manner by ferric citrate, ferric filter use, is said to be in the form of granules of citrate, ferroammonium citrate, ferroacetate or ferrous or particles with a particle size between about 25 ammonium carbonate. Inorganic 8 and 50 mesh (sieve openings of about 2.38 and ferrous or ferrous salts are excluded, since they are 0.3 mm), ie of such a size that ferrous or ferrous hydroxides precipitate from these, which are precipitated by the diarrhea fraction of a sieve the US if they are mixed with the ammoniacal zinc carbonate serial number 8 and the residue fraction of a solution.

Sieves of the US serial number 50 with one another 30 The percentages by weight of zinc oxide and following sieving is determined. Particles larger than iron oxide can best be found by adjusting the 8 mesh (sieve opening 2.38 mm) are difficult to manage. Concentration of the zinc compound or the iron trade and bring them into the chamber of the filter element in a controlled manner in connection with the treatment solution. Particles smaller than 50 mesh (sieve opening den. For example, treating 10 g 0.3 mm) adversely affect the flow 35 gas adsorption carbon from Pittsburgh Chemical Corp. resistance in the filter. Grade BPL 12 to 30 mesh with 24 ml of a solution that

The impregnated adsorbent, e.g. B. active 18.6 mg / ml zinc ions and 21.9 mg / ml ferric ions carbon, can by impregnating a highly activated contains, after the heat treatment described above, carbon in an aqueous solution of zinc carbonate, a carbon that is 2.30 ° / ₀ Zinc oxide and 1.76% iron ammonia and ferric ammonium citrate are produced which contain oxide, calculated as Fe ₂ O ₃ . Such a solution can be created by adding another 10 g carbon sample with 24 ml of a Lö zinc carbonate in ammoniacal water and a solution containing 109.0 mg / ml zinc ions and 77.5 mg / ml ferric ammonium citrate in water separately from ferric ions , resulted in an im to be dissolved after roasting. The two solutions are then mixed in-impregnated adsorbent with a content of the desired amounts to a Behänd- 45 ° 7.96 / ₀ of zinc oxide and that in turn to obtain lung solution 5.31 ° / ₀ ferric oxide. Alternatively and preferably it was calculated _{as Fe 2} O _3. These examples, and those, zinc carbonate, ferriammonium citrate and water, which will be described later, will illustrate how water is added to a reaction vessel and ammonia and the oxide content are passed through the concentration of metals until a salt saturated with ammonia at 28 ° C is established in the treatment solution . Solution is obtained. This solution can be used as it is. required metals can be controlled.

After soaking for 5 to 20 minutes, in the case of such treatments, the charcoal is soaked in considerable amounts of air by the solution-required solution and the wetted charcoal treatment is displaced from the porous charcoal, 55 ^{heated to HO 0} C until it has dried. The excess solution is then sucked off. The process is repeated until the desired carbon grains are then roasted to achieve the treatment effect. This process is attached to the adsorbed salts to the corresponding metal, if poorly soluble iron salts in the oxyden decompose. The adsorbed zinc ammonium treatment solution can be used, for example carbonate component decomposes to release 60 ferroammonium carbonate.

of ammonia and carbon dioxide under back- It has been found that the treatment of the ad-

Release of a residue, which consists mainly of sorbents with oxide mixtures in the case of a Ge zinc oxide. This residue is about / uniformly distributed samtoxydgehalt greater than 1 ° ₀ and less in the porous carbon granules. The ferriammonium sorbent decomposes in about 14%, based on the weight of the ad. With im- and the thermal degradation products of the citrate. prägnierungen of less than about l ° / ₀ to the residue, treated in the degradation of this component adsorbent of undesirable overall liable

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taste of the untreated adsorbent. calic solution. The coal used, the im-bei An oxide content greater than about 14% will use the impregnation and roasting process for samples 8A Adsorption capacity of the adsorbent and 9 A were the same as when the pregnant. Treated Activated Carbon used relative to Sample 7A.

their weight, 1 to 13 weight percent zinc oxide and 5 The five above cigarette samples that are made from 1 to 13 percent by weight iron oxide was found to be effective as a blank (5 A) from a sample with untreated found, the preferred content of each system being carbon (6A), from a sample with both

Oxyds is between 4 and 6%. carbon treated with zinc and iron oxides

Based on the following examples, the substance (7A) is derived from a sample with iron oxide alone

finding further explained. io treated carbon (8A) and from a sample

A mixture of 447 g zinc carbonate, 1584 g carbon treated with zinc oxide alone (9A)

Ferriammonium citrate (brown) and 2160 ml of water were passed as described below were dissolved by subjecting ammonia gas to the Mi-experiments.

Research was conducted membered to saturation at 28 ⁰ C. The samples were five cigarettes to their content

was enough. 750 ml of this solution was mixed with 500 g of 15 hydrogen cyanide in the exiting smoke under-coal grade BPL, 12 to 30 mesh, from Pittsburgh. Five sample cigarettes from each of the five Chemical Corp. cigarettes, while stirring for 10 minutes in samples, were placed on an automatic smoke contact. The excess solution was machine down to a stub of 30 mm, smoked, removed by vacuum filtration, and the wetted by 2 second puffs with a stroke carbon was withdrawn for 1 hour in a slow 40 ml space once every minute -Water vapor flow at temperatures between the. The smoke machine and the smoke collector-400 and 500 ⁰ C roasted. It has been found that the systems are described by Keith and Newsome in resulting charcoal 5.8% iron oxide, calculated as Tobacco Science, Vol. 1, p. 51 (1957). Fe ₂ O ₃ , and 4.3% zinc oxide. 85 to 100 mg In general, after seven puffs of these impregnated charcoal, the cigarettes were used up in 5 mm puffs. After smoking for a long time been chamber between two 7.5 mm long cigarette soft all five samples, the collecting vessels, which were cooled with a Zelluloseacetatfilterstopfen made Fa during smoking to -70 ⁰ C, to dendenier of 2.8 and a total denier warmed from O ⁰ C in an ice bath and introduced to 50,000 for 10 minutes. This 20 mm long plug was kept at this temperature to enable 65 mm long cigarettes to be attached, which would strip off interfering volatile materials. The standard tobacco mixture customary for collectors contained, containers were then repeatedly extracted with small amounts, whereby a finished 85 mm long cigarette was extracted with one of Ο, ΐη sodium hydroxide solution until a little less of 24.75 mm was obtained. These cigarettes were obtained as a 250 ml solution. These solutions are referred to as 7A. was with 0, In-NaOH to 250 ml to measure the

Various other cyanide contents have been made up for comparison purposes.

Trial cigarettes manufactured. These all had the same The cyanide content of the smoke solutions was through

Dimensions, consisted of the same tobacco mi- using a modified electrolysis technique and had the same cellulose acetate filters as measured by Becker and Morrison drip like the cigarettes of sample 7A. The only one in "Analytical Chemistry", Vol. 27, p. 1306 (1955), The difference was in the material described in the middle 40. A solution that removes the cyanide ions. The numbers of the samples and the materi- al-holding, generated when placed between a silver electrode lien in this chamber were the following: and a platinum electrode is placed while

an electrolytic current for a few minutes. If this current at certain times and at certain

Sample 5A: empty chamber; ₄₅ specific resistances measured in the circle and

",,. ,,. ,, -. ,, τ ™ T ^ 11 ^w ith the current is compared to a cyanide

Sample 6 A: chamber with untreated BPL Kõue, _lö known composition generated, the

as received from the manufacturer, cyanide content can be determined in this way. the

lulled, measurement of the standard cyanide solution is carried out directly after

Sample 7A: Chamber filled with BPL carbon, which, as 5 ° of the measurement of the smoke solution and in exactly the same

described above, with 5.8% iron oxide and with the same resistances in the circle

(calculated as Fe ₂ O ₃ ) and 4.3% zinc oxide. Since the electricity generated is directly proportional

was impregnated; ^{tlonal of} the cyanide concentration, the Cayn-

hydrogen content of the solution simply from the VerProbe 8 A: Chamber filled with BPL carbon, which impregnates with 55 ratio of the read currents for the smoke solution 7.3% iron oxide (calculated as Fe ₂ O ₃ ) ^with the unknown content and the known one without the addition of zinc oxide was; cyanide-containing solution can be determined. These values

are expressed in units of micrograms of cyanogen

Sample9A: Chamber filled with BPL carbon, which is converted with substance per 40 ml smoke volume. The five 6.6% zinc oxide and without iron oxide - 60 cigarettes of each cigarette sample 5 A, 6 A, 7A, 8 A and

additives was impregnated. 9 A were tested in this way and the

—- the average values and the variation between them

Average values from the standard measure are given in

The impregnation solution for the cigarettes is listed in the table below.
Sample 8 A contained 600 g of ferric citrate in 11 saturated 65 The hydrogen sulfide content of the smoke from ammoniacal solution. The impregnation solution in the cigarette samples 5A, 6A, 7A, 8A and 9A, the sample 9A consisted of 187.5 g of zinc carbonate, was determined by a color reaction under and 40.0 g of citric acid per 11 of saturated ammonia formation of methylene blue. It was

009 532/187

9 10

especially the process that HB Jakobs promoted on the sloping surface of the sample upwards, "Analytical Chemistry of Industrial Poisons, Hasards, which is described at the top in the Ab- and Solvents chamber", 2nd edition, p. 326 , dripped. The concentrated cloud of smoke from each puff applied. In this case, 13 ml of l ° / _o aqueous sodium remained with the trachea for 10 seconds in contact, zinc acetate and 0.5 ml of 10 ° / _o aqueous sodium hydroxide solution, after which test chamber 5 with wasserdampfgein rinsed an evacuated envelope of about 55 ml volume of air saturated with was introduced until the next smoke. The piston is then let in via a torrent.

Limiting mouthpiece and a Cambridge The normal action of the cilia involved in removing

CM-113 filter pad with a burning cigarette consisting of small solid particles of foreign matter has been through connected, so that in this way a smoking device io dusting up a small number of carbon particles tion is formed. The vacuum in the flask, which ranges from 50 to 100 microns in size, is applied to the cilia a level was set which observes a tissue. It could be the movement of this Smoke extraction of 40 ml from the cigarette ensures particles along the trachea by means of a microscope performs, pulls the cigarette smoke through the filter. It was further observed that pillow and the mouthpiece. The filter pad separates the 15 cilia which condensed the particles at a constant speed Smoke particles and the mouthpiece moved a speed of 20 to 30 mm per minute, or the nozzle limits the speed at which the chamber was filled with saturated air. the the smoke gases of the cigarette are taken, so specimens occupied with cilia were successively the that in this way normal puffs of at least puffs of smoke are exposed to each cigarette until each cilia-2 Seconds in duration similar to those carried out after 20 working days or until the cigarette after eight who had finished smoking puffs taken by automatic smoke machines.

will. In this experiment, the fourth puff of samples 6A, 7A, 8A and 9A was the

taken all cigarettes, as this is the closest to slowing down the movement of the cilia, but not completely Average of all puffs from a cigarette represent- prevented. The percentage of hindrance after eight animals. The previous puffs were on the auto- 25 cigarette puffs is shown in the table. The Zimatas Smoke machine mentioned above, garette sample 5 A caused a complete passage, and the cigarette was between the ciliary movement after three or six third and fourth puffs with the piston smoke puffs. Commercially available unfiltered cigarette device connected. After the ten often caused complete paralysis of the Smoke gases were drawn into the evacuated flask, 30 ciliary action after a puff of smoke in this case the flask closed and shaken to seek, and generally complete, paralysis the hydrogen sulfide in the reagent solution to off after two puffs.

sorb. Then 2.5 ml of a solution that The five cigarette samples were a taste

0.1 g of M, N-dimethyl-p-phenylenediamine sulfate in 100 ml test by a group of three test persons containing HCl in H ₂ O (1: 1) was added. 0.5 ml of a subject 35 who had experience in the description and 0.02 molar solution of ferric chloride in a chlorine evaluation of the taste and aroma of hydrogen-water mixture (1: 9) were also cigarette smoke. The working method of this admitted. The flue gas solution with these subjects is in "Perfumery and Essential Oil Sentences Were Shaken Further and Overnight Record", Vol. 49, p. 130 (1958), and in an article left to complete the color development Salzmann in Bulletin CORSETA, standing. At that time, the optical density was described in No. 1961-1, p. 120 (1961). The cigarettes measured a wavelength of 665 millimicrons. were designated and were obscured during evaluation by comparing this optical density with that of. Each smoker rated each cigarette dye solutions containing known hydrogen sulfide - zero to five points for the desired mixtures - the concentration of 45 flavors, i. That is, the fragrance of sweetness and the hydrogen sulphide in the flue gases determine mildness as well as the undesirable flavors. These measurements were made on ten cigarettes, that is, the bitter taste and irritation of each sample 5A, 6A, 7A, 8A and 9A, the throat. The evaluation number zero indicates the low The average and the deviation of the average quality grade and the evaluation number 5 the average values of these measurements from the norm are in 50 the highest quality grade. The results are shown in the table. Table listed.

The five sample cigarettes were checked for their inherent properties. Each of the five cigarette samples were then one

Binging effect on the mobility of the cilia in a taste test with nine test persons Trachea of rabbits examined. Subjected as a technique that has a great experience in describing the method used was that of 55 and evaluating the taste and aroma of Battista in the ADL Review, June 1962, had cigarette smoke. The taste characteristics which was written by Arthur de Little Inc. of were from the same point of view as that Cambridge Massachusettes is published. Evaluated in the experiment with the three test persons, In this measurement, seven cigarettes of each of the cigarettes were identified and tested 5A, 6A, 7A, 8A and 9A in a device 60 such designation obscured as at smoked a 40 ml puff once a minute in the experiment with the three subjects. Every extracted. The smoke was given directly by an ex-test subject regardless of its rating isolated sample of the rabbit trachea. That of the others. These ratings were made during Cilia sample was not uncovered by the subjects at an inclined angle in the experiment Examination chamber arranged and continuously exchanged. Same rating scale from 0 to 5 as with a physiological Tyrode saline solution in the experiment with the three test subjects loaded at their lower end. By the effect also for this experiment with nine test persons A film of this solution was applied to hair-like cilia.

5A

sample
7A

8A

9A

Activated carbon

Impregnated oxide

Average HCN content in micrograms per puff

Deviation of the HCN content from the normal value

Average H ₂ S content in micrograms per puff

Deviation of the H ₂ S content from the normal value ciliary inhibition after eight puffs in%

no

37.3

(± 1.4)

4.39

(± 0.23)

no

18.2

(± 1.8)

2.40
(± 0.19)
16

Fe + Zn

15.2
(± 1.2)

1.86
(± 0.20)
15th

Fe

21.0
(± 1.0)

2.09
(± 0.20)
23

Zn

18.5
(± 0.9)

1.63

(± 0.10)
30th

Desired flavors, expressed in rating numbers from 0 to 5 Sweet fragrance [fragrance] (three test subjects) ..

Sweet Fragance (nine subjects)

Mildness (three subjects)

Mildness (nine subjects)

0 0 3 1 Valuation numbers from 0 to 5 1 2 1 1.8 2.2 2.7 2.3 2 1.7 2.2 2.2 1 3 4th 3 2.1 1 3 2 2.0 3.2 3.4 2.9 2 2.1 2.6 2.7 igen in 1.9 3 3 2.5 2.3 4th 2 ZJS 2.3

Bitter taste (3 man trial)

Bitter Taste (9 Man Trial)

Irritation of the throat (3-man attempt)

Irritation of the throat (9-man attempt)

*) The ciliary inhibition was 5 A after three to six puffs in each experiment made with a sample cigarette was, 100%.

The cigarette filter of this invention which contained both iron and zinc oxide in one Impregnating carbon supports (Sample No. 7A) removed significantly more hydrogen cyanide from the Tobacco smoke than this is a filter that uses either iron oxide or zinc oxide alone was impregnated (sample 8 A or 9A), or a non-impregnated carbon filter (Sample 6A) did. The smoke from cigarette sample 7 A, which was prepared according to the invention, contained more Hydrogen sulfide as the smoke of cigarette sample 9 A, but less than the smoke of any of the other cigarette samples. The cigarettes with filters according to the invention had the lowest ciliary inhibition recorded any of the samples examined, namely 15% after eight puffs. The ciliary inhibition, that was observed with cigarettes, which had activated carbon filters, those with either iron oxide or zinc oxide alone were impregnated (samples 8 A and 9A, respectively), was much larger. The invention Cigarettes are noticeably superior to other cigarettes in terms of taste, both in Regarding the desired flavors as well as the lack of undesirable flavors. This resulted in both the 3-man trial and the 9-man trial.

Other types of adsorption carbon can be used instead of the types described in the examples same results can be used.

Claims (3)

Patent claims: 1. Smoke filter for tobacco products with a filter space through which the smoke can flow and which contains an active adsorbent granulate with a specific surface area over 1000,000 cm ² / g granulate and a particle size between 2.38 and 0.30 mm and metal oxides, thereby in that the adsorbent granules are impregnated with finely divided iron and zinc oxides, each oxide in an amount of not less than about 1 ° / o and not more than about 13 ° / _0, based on the weight of the adsorbent granulate, and The combined content of the two oxides does not exceed 14 percent by weight of the granulate. 2. Filter according to claim 1, characterized in that one or both of the oxides in one Amount between about 4 and 6% are present. 3. A method for manufacturing a filter according to claim 1, characterized in that the material for the adsorbing granulate with an aqueous solution of (a) zinc carbonate, zinc oxide or zinc acetate, (b) ferriammonium citrate, ferricitrate, ferroammonium citrate, ferrocitrate, ferroammonium acetate, Ferroacetate or ferroammonium carbonate and (c) ammonia is soaked and then to decompose the adsorbing salts is heated.