Tobacco – Tobacco users' appliance – Device used for smoking
Reexamination Certificate
2001-03-28
2003-07-15
Colaianni, Michael (Department: 1731)
Tobacco
Tobacco users' appliance
Device used for smoking
C131S201000, C131S331000, C131S332000, C131S334000, C131S341000, C131S342000, C131S346000
Reexamination Certificate
active
06591839
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a filter material for reducing harmful substances in tobacco smoke.
2. The Prior Art
Tobacco smoke is produced when tobacco is burning down. Said smoke is an aerosol consisting of a gas phase and a condensate phase. The gas phase of the tobacco smoke has a relatively simple composition and, in addition to nitrogen, oxygen, carbon dioxide, hydrogen and inert gases, also contains the toxic substances carbon monoxide (about 4.2%), hydrogen cyanide (about 0.16%), ammonia (about 0.03%), nitrogen oxides (about 0.02%), and traces of hydrogen sulfide. On the other hand, the main component of ingredients is found in the condensate phase (“tar”), including also the flavoring and odorous substances forming the aroma of tobacco smoke.
It is known since a long time that smoking is harmful to health in the long run. It has not as yet been entirely clarified which components of tobacco smoke in detail exactly cause the effects, which are observed to varying degrees depending on the smoking habits, the tobacco consumption and the constitutional disposition of the smoker, etc. The statistically increased susceptibility of smokers to arteriosclerosis, coronary diseases and myocardial infarction, as well as the tendency to gastrointestinal diseases are ascribed to the effects of nicotine, and attributed to some extent also to the effects of carbon monoxide. Another toxic substance, namely hydrocyanic acid, inhibits the regeneration of the ciliary epithelium in the respiratory tract, and prevents the formation of leukocytes. The very frequent occurrence of diseases in the region of the pharyngeal space, and in particular the occurrence of bronchitis (smoker's cough) are associated with the phenol, acid, aldehyde and ketone components of tobacco smoke.
Filter cigarettes, filter cigars and filter cigarillos, as well as cigarette and cigar holders and tobacco pipes have been developed for reducing the content of harmful substances in tobacco smoke, with mouthpieces containing filter materials for removing part of the nicotine and tar substances without substantially filtering out the aroma substances. Such filter materials consist of cellulose, cellulose acetates, polyethylene, crepe and paper, or active carbon.
Silicate-containing minerals, in particular clay, kaolin and feldspat are used as adsorbents for tobacco filters according to DE-OS 15 17 272. However, the drawback is that said filter materials, according to the laid-open specification of said patent, have to be made free of adhering ions by means of a treatment with distilled water or acids, or by electrolysis or electrodialysis, in order for them to be usable. Furthermore, mainly tar substances of the condensate phase and less the toxic substances of the gas phase are reduced.
Furthermore, filter materials are used which form a film, and which consist of a binding agent such as methyl cellulose and a finely fibrous material, the latter being provided with adsorbents. Active carbon, silica gel, asbestos fibers or polyethylene glycol are specified as adsorbents. Said filter material offers the advantage of filtering out defined harmful substances, in the present case primarily phenol, by applying selectively acting absorbents. In addition to the use of asbestos fibers, which have been proven to cause cancer, the drawback in this case is that the major part of the flavoring and odorous substances of the tobacco aroma is filtered out.
DE-OS 15 17 298 specifies filter materials consisting of active carbon grains with a maximum diameter of 0.1 to 2 mm, which are linked via a vehicle such as polyvinyl resin or polyethylene. Again, the drawback is that mainly the tar substances and thus also the flavoring and odorous substances of the tobacco smoke aroma are filtered out, but not the toxic components of the gas phase such as carbon monoxide, hydrocyanic acid or ammonia.
According to DE design patent 87 06 686, another filter material consists of a mixture of active carbon particles and meerschaum (sepiolite), which serves for reducing the tar substances, harmful substances and the nicotine, as well as the odorous substances. Meerschaum or sepiolite represents a porous mineral, which adsorbs much moisture in addition to tar substances and nicotine. The adsorptive effect of the active carbon for odorous, harmful and tar substances is increased by binding the moisture. However, the drawback is that in addition to the odorous substance, the flavoring substances of the tobacco smoke aroma are filtered out as well.
In German laid-open document DE-OS 29 25 001, mention is made of clays as filter materials, which can be applied to carrier materials such as cellulose acetate fibers or paper because of their gel- and film-forming properties. Decisive for the application of such materials is their swelling property. Therefore, primarily bentonites such as sodium montmorillonite and sodium attapulgite are suitable.
Furthermore, filters are known for cigarettes, cigars, cigarillos, cigarette and cigar holders as well as tobacco pipes which contain either pure silica gel or pure active carbon.
The drawback of such filter materials is that they predominantly reduce the tar substances of the condensate phase, but less so the toxic substances of the gas phase. Since the flavoring and odorous substances forming the aroma of tobacco smoke are present also in the condensate phase, and reduced jointly with the tar substances, the utilization of such filter materials has a negative influence on the pleasure of smoking. A further drawback of such materials is the short duration of the filtration effect of said filter materials. Particularly with filter materials used in cigarette and cigar holders as well as in tobacco pipes, which are reused many times, the degree of saturation and thus the loss of filtration efficiency are reached in a relatively short time. Furthermore, the smoker is required to apply increased drawing force when smoking with some filter materials because the density of the filter material is so great that the tobacco smoke will not freely flow through the filter material.
SUMMARY OF THE INVENTION
The invention is based on the problem of providing a filter material which, in addition to improving the reduction of the tar substances present in the condensate phase, eliminates the toxic substances of the gas phase as completely as possible without reducing at the same time the aroma of the tobacco smoke and thus the flavoring and odorous substances. Furthermore, the goal of the invention is to provide a filter material that assures long-lasting filtration efficiency and permits easy passage of the tobacco smoke through such filter material without requiring the smoker to apply increased drawing force during smoking.
This object is accomplished by a filter material that comprises a ground and not additionally activated expanded clay produced without adding foreign substances, as well as zeolite. The expanded clay is a synthetically produced filter material based on natural lime-containing raw clay. To produce the expanded clay, the natural raw or crude clay is shaped into small, round pieces and subsequently burned in special calcinators, so-called rotary tubular furnaces, at a high temperature (about 1200° C.) with a feed of air.
The small round pieces are first caused to expand in the course of the burning process under heat, and the surfaces of the small spheres of clay are then slightly sintered (melted). The interior of the small spheres has a porous structure with numerous air inclusions. The expanded clay is thereafter ground.
Therefore, the expanded clay is produced without adding any foreign substances. An expanded clay so produced has an optimal filtration effect and does not need to be additionally activated. Thus, there is no additional process required to turn the ground expanded clay into a more reactive activated condition.
By using expanded clay as filter material for tobacco products such as cigarettes, cigars or cigarillos, and for smoking utensils su
Braun Hans-Peter
Meyer Dieter
Colaianni Michael
Collard & Roe P.C.
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