COMPOSITION AND METHOD FOR REMOVING POLYNUCLEAR AROMATIC HYDROCARBONS FROM BURNING TOBACCO GAS-SMOKE

摘要

1333606 Cigarettes; cigars; tobacco smokefilters; tobacco compositions E W MERRILL 22 Dec 1970 [29 Dec 1969] 60709/70 Heading A2C [Also in Division C3] An absorbent for use in cigars and cigarettes comprises a solid polysiloxane of molecular weight at least 100,000, and at least 50 parts by weight per 100 parts of polysiloxane of a filler capable of endothermically releasing carbon dioxide or water vapour on heating below 600‹C. The polysiloxane may contain units Me 2 SiO, alone or with MePhSiO and/or MeViSiO units, and may be cross-linked; suitable fillers release CO 2 and/or H 2 O and include those exemplified below and Nesguehonite (MgCO 3 .3H 2 O), NaHCO 3 and gypsum. The absorbent is mixed with tobacco or used as a filter; the polysiloxane absorbs polynuclear aromatic hydrocarbons from the smoke; the filler maintains a lower temperature in the presence of burning tobacco. In Examples 1 and 2 chopped fibres are made from a commercial SiO 2 -reinforced polysiloxane gum cured by irradiation and containing Mg(OH) 2 , Fe 2 O 3 and carbon (Ex. 1) or a commercial RTV polysiloxane containing Epsom salt and Fe 2 O 3 (Ex 2) and mixed in 2:1 or 3:1 ratio with tobacco and incorporated in cigarettes. In Example 3 sheets of cured commercial polydimethylsiloxane gum containing sodium metasilicate monohydrate, Fe 2 O 3 and carbon are interleaved with tobacco leaves in a cigar. In Example 4 a cigarette filter is made from cured tubes of polysiloxane gum containing Artinite (Mg(OH) 2 .MgCO 3 .3H 2 O).