| 摘要 |
1315068 Tobacco-smoke filters BRITISHAMERICAN TOBACCO CO Ltd 24 Aug 1971 [25 Sept 1970] 39689/71 Heading A2C [Also in Division C3] A tobacco smoke filter material comprises a particulate salt of a porous weakly basic anionic exchange resin, said salt being formed by the at least partial neutralisation of the basic resin by an acid having a pk a value between 3.5 and 5.5. The porous anion exchange resin matrix of the weakly basic resin may be of the polystyrene, styrene divinylbenzene, phenolic, acrylic or aliphatic type and the weakly basic resin may be formed by combining a polyamine with the resin matrix. Suitable modifying amines are ethylenediamine, diethylenetriamine, triethylenetriamine, tetraethylenepentamine, propylenediamine and mphenylenediamine. The porous granular resin particles preferably have a surface area of 1-100 m<SP>2</SP>/gm, and the pore volume of the granules is preferably 0.2-0.5 ccs/gm. The average pore diameter is 0.01-1 micron. Particularly preferred porous weakly basic anionic exchange resins are amine-modified phenolformaldehyde resins. Preferred weak acids are aromatic carboxylic acids such as benzoic acid cinnamic acid, and anisic acid; aliphatic dicarboxylic acids such as succinic acid and glutaric acid; aliphatic monocarboxylic acids such as propionic acid, valeric acid, caproic acid, heptonoic acid, caprylic acid and perlargonic acid. Weak acids which have proyed to be especially efficient in removing volatile components from tobacco smoke are acetic acid and glutamic acid. A cigarette filter may be prepared by encasing the filter material in an outer wrapper. The resulting filter may be employed alone or in combination with a cellulose acetate filter. |
