A Cigarette filter is an element of an cigarette, in addition to cigarette paper, capsules and adhesives. The filter may be made out of cellulose acetate fibre, paper or activated charcoal (either being a cavity filter or embedded to the cellulose acetate). Macroporous phenol-formaldehyde resins and asbestos have been found in cigarette filters The acetate and paper change the particulate smoke phase by particle retention (filtration), and finely divided carbon modifies the gaseous phase (adsorption). Filters is effective in reducing “tar” and nicotine smoke yields around 50%, having a greater removal rate for other classes of compounds (e.g., phenols), but they are ineffective in filtering toxins for example co. Most factory-made cigarettes come with a filter; those who roll their own can get them coming from a tobacconist.

Cellulose acetate is manufactured by esterifying bleached cotton or wood pulp with acetic acid. In the three cellulose hydroxy groups intended for esterification, between two and three are esterified by governing the amount of acid (a higher level substitution (DS) 2.35-2.55). The ester is spun into fibers and formed into bundles called filter tow. Flavors (menthol), sweeteners, softeners (triacetin), flame retardants (sodium tungstate), breakable capsules releasing flavors on demand, and additives colouring the cigarette smoke may be put into cigarette filters. The 5 largest manufactures of filter tow are Hoechst-Celanese and Eastman Chemicals in the United States, Rhodia Acetow in Germany, Daicel in Japan, and Courtaulds in britain.

Starch glues or emulsion-based adhesives can be used for gluing cigarette seams. Hot-melt and emulsion-based adhesives are used for filter seams. Emulsion-based adhesives are used for bonding the filters for the cigarettes.

Cellulose acetate is non-toxic, odorless, tasteless, and weakly flammable. It can be resistant to weak acids and is largely stable to mineral and fatty oils and also petroleum. It really is biodegradable and the raw material is a renewable natural polymer supposed to find application for other uses down the road. Smoked cigarette butts contain 5-7 mg nicotine (about 25% from the total cigarette nicotine content), children ingesting >2 whole cigarettes, 6 cigarette butts or perhaps a total of 0.5 mg/kg of nicotine needs to be admitted with a hospital. Cellulose acetate is hydrophilic and retains the water-soluble smoke constituents, that many are irritating (acids, alkali, aldehydes, and phenols), while letting over the lipophilic aromatic compounds.
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