FI63331B - TOBAKROEKFILTER - Google Patents

Description

-1 fBl M4. ADVERTISEMENT / 7 7 71 t>] ('' »OTlAeONINOSSKRIFT 60001 c .... Patent granted 10 06 1933 'Patent meddelat ^ T ^ (51) Kv.ik? /Int.ci.3 A 24 D 3/14 FINLAND —FINLAND pi) ρκ »« μιμμ-λι * («ιι · ιιι * ιι 773676 (22) H» k * mhp «W« - Amdknlnpdag 02.12.77 * (23) AlkupUvi — GHtlfh * t * da | 02.12.77 (41) Tullut | ulklMksl - Bllvft offantlig _ Qg ~ g Pledge · | a Pledge Board of Directors (44) Date of Nlhtlvlkilpanon and kuLJullulst

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English-England (GB) 46592/76 (71) British-American Tobacco Company Limited, Westminster House, 7, Millbank, London SWI, English-Englar.d (GB) (72) John David Green, Romsey, Hampshire, Ian Richard Harris, Alton,

Hampshire, England-England (GB) (7 * 0 Leitzinger Oy (5 ^) Tobacco Smoke Filter - Tobacco Smoke Filter The present invention relates to filters or filter media for tobacco smoke, in particular, although not exclusively, to cigarette filters.

Filters made of a fibrous or filamentous material such as paper or cellulose acetate are known to remove particulate matter from tobacco smoke. Absorption or adsorption to the surface or a chemical reaction can to some extent remove some of the other components of tobacco smoke, such as aldehydes, cyanides, sulfides, and oxide. One of these vapor phase constituents that has been found to be difficult to remove from tobacco smoke is nitric oxide. Nitric oxide belongs to a group of molecules whose electronic structure is such that they have an odd electron, which gives nitric oxide the nature of a free radical.

The tobacco smoke filter according to the invention, which contains a filter material to which a permanent non-volatile free radical nitroxide has been added, is characterized in that the material to which the nitroxide is applied is a particulate, porous, activated carbon 2 63331 [k and said nitroxide is 4-oxo-2, 2,6,6-tetramethylpiperidinoocinonitrocide and / or 1-nitronyl-3-oxyl-4,4,5,5-tetramethyl-2-phenylhydroimidazoline nitroxide, to which nitroxide has been added 0.5 to 25%, preferably 1 .0 to 15% by weight of carbon.

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It is therefore essential to the invention that the activated carbon is combined; and nitroxide. The filter according to the invention achieves a lower; the amount of nitroxide and, more economically, the same filtration efficiency as the use of nitroxide alone as disclosed in U.S. Patent No. 3,623,490, which mainly describes the prior art of the invention.

As a filter or material according to the invention, it is possible! remarkably efficiently and without concomitant adverse effects, removes in particular nitrogen oxide (NO) and other constituents that may be desired to be removed. The reduction in the amount of nitric oxide is believed to be related to the porosity of the treated carbon, and that the pore volume should preferably be at least 0.2 cm / g and the carbon surface area at least 50 m / g. The structural formula of the preferred compound f, 4-oxo-2,2,6,6-tetramethylpiperidinoxynitrokide, is: {

O

r * D

CH3 ^ ^ CH

> "·« 'Λ ch3 I ch3 o

The amount of nitroxide added, expressed as a percentage by weight of the untreated carbon, may be 0.5 to 25 S and is preferably between 1.0 and 15%. In commercial practice, the rate of increase will probably be between 3 and 10%.

Example 1: 1 g of porous granular coal of the type "BPL" manufactured by Pittsburg Activated Carbon Co. was added to a solution containing 100 mg of 4-oxo-2,2,6,6-tetramethylpiperidinoxy. in ml of ethanol. The solvent was allowed to evaporate at room temperature until granular carbon! was dry and free flowing. The amount of addition was then about 10 K. A triple filter between two cellulose acetates 63331 thios, each 5 mm long, a layer of 100 mg of this treated carbon was attached to a cigarette filled with flue-gas-dried tobacco. .

When the cigarette was burned through this filter, 72% by weight of nitric oxide was removed from the tobacco smoke.

Using the same addition method as in Example 1, experiments were performed using many of the available granular activated carbon and different addition amounts of the same nitroxide as in Example 1. The results are summarized in the following table.

Carbon Addition - N0 filtration - N0 filtration rate efficiency, slip, carbon (w / w) li and nitrous oxide without nitric oxide 3BL 10 72 less than 10 BPL 5 60 less than 10

Anthraeorb CC1430 / 70 10 68 under 10 1F3 10 57 13

Actibon X 10 45 under 10 'icatif 60143 7 43 under 10' arbomafra GC 7 43 under 10 207C 10 43 17

The producers of the different types of coal were: BPL Pittsburgh Activated Carbon Co.,

Pennsylvania, U.S.A.

Anthraeorb CC1430 / 70 Cardian Chemical Co.,

Cheltenham, England MF3 Chemviron Ltd,

Brussels, Belgium

Actibon X Hooker - Mexicans S.A. de C.V.,

Mexico

Picatif 60143 Pizza,

Paris, France / »4 63331;

Carbomafra GC British Traders & Shippers Ltd,

Dagenham, England 207C Sutcliffe - Speakman Ltd.,

Leigh, Lancashire, England

Actibon X was made by treatment with 0.1M aqueous sodium hydroxide solution before application on carbon to a non-acidic mixture.

Example 2: 1-Nitronyl-3-oxyl-4,4,5,5-tetramethyl-2-phenyl-dihydroimidazole was applied to the above-mentioned BPL-type carbon granules using the same procedure as in Example 1, but with an addition rate of 5%. A third filter was prepared as described in this example. Nitric oxide filtration efficiency was not obtained at 44%.

The amount of treated carbon applied to the filter depends on the required filtration efficiency and the nitroxide used. :

The following table illustrates the effect of changing the amount of treated> carbon: The results tabulated above were obtained with the same type of Anthrasorb-type granular carbon treated according to Example 1 so that 4-oxo-2,2,6,6-tetramethylpiperidinoxy the amount of nitroxide added was 7%. The treated carbon was placed in the triple filters described in this example.

t weight of carbon Filtration efficiency of NO (mg) (¾) 25 29 50 50: 75 50 100 61 150 75 200 Θ1 «5 63331

The filtration efficiency of nitric oxide can be improved by so-called "ventilation" of the filter, for example by using perforated or porous wrapping paper. Thus, the filtration efficiency of the filter can be significantly improved if, in a triple filter, the central part of which is formed by a layer of treated carbon, either the tobacco-side end or said central part is ventilated in a known manner. For example, cigarettes containing flue gas dried tobacco were fitted with a triple filter of this type when the wrapping paper in the center of the cigarette had ventilation holes.

There were three rows of holes at 1 mm intervals, and the holes were rectangular (0.1 mm x 0.5 mm), and the first row was located 7 mm from the end of the tobacco column. In the above-mentioned layer, 100 mg of Anthra8orb type carbon having a 10% addition rate of 4-oxo-2,2,6,6-tetramethylpiperidinoxynoxide was used. When the ventilation holes were closed by covering them with non-porous tape, the amount of nitric oxide was reduced by a total of 67 3, while when the holes were uncoated, the reduction was a total of 89%.

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Claims (7)

A tobacco smoke filter comprising a filter material to which a permanent non-volatile free radical nitroxide has been added, characterized in that the material to which the nitroxide has been applied is particulate blue, porous activated carbon and said nitroxide is 4-oxo-2,2,6, 6-Tetramethylpiperidinoxynitroxide and / or 1-nitronyl-3-oxyl-4,4,5,5-tetramethyl-2-phenyldihydroimidazoline nitroxide, to which nitroxide has been added 0.5 to 25 K, preferably 1.0 to 15 S the weight of carbon. A filter according to claim 1, characterized in that the layer of treated carbon forms one part in a filter with at least one other part of a different smoke filter material. A filter according to claim 1, characterized in that said layer is located between two other parts of the material to be filtered. A filter according to claim 2 or 3, characterized in that the smoke filtering material of said other part or parts is filamentous. A filter according to claim 2, 3 or 4, characterized in that the smoke filtering material of at least one of said other parts is cellulose acetate. Filter according to one of Claims 1 to 5, characterized in that the filter is provided with ventilation. 6 k 63331 A filter according to claim 6, which is a triple filter, the central part of which contains treated carbon, characterized in that said central part and / or its part above its flow is ventilated.