Originally, cigarette filters were made out of cork, the look of which was incorporated into today’s pattern.
A cigarette filter, also known as a filter tip, is a component of a cigarette, along with cigarette paper, capsules and adhesives. It does not make cigarettes less unhealthy.
The filter may be made from cellulose acetate fibre, paper or activated charcoal (either as a cavity filter or embedded into the cellulose acetate). Macroporous phenol-formaldehyde resins and asbestos have also been used in cigarette filters. The acetate and paper modify the particulate smoke phase by particle retention (filtration), and finely divided carbon modifies the gaseous phase (adsorption). In laboratory testing, filters have been shown to reduce "tar" and nicotine smoke yields up to 50%, with a greater removal rate for certain classes of compounds (e.g., phenols) compared to others—the filters are particularly inefficient at removing gases of very low molecular weight, such as carbon monoxide. In addition, most of these measured reductions occur only when the cigarette is smoked on a smoking machine; when smoked by a human, the compounds are delivered into the lungs regardless of whether or not a filter is used.
Most factory-made cigarettes are equipped with a filter; those who roll their own can buy them from a tobacconist. The near-universal adoption of filters on cigarettes has not reduced harms to smokers and lung cancer rates have not declined.
Filling a given length of cigarette with filter is cheaper than filling it with tobacco.
Cellulose acetate is made by esterifying bleached cotton or wood pulp with acetic acid. Of the three cellulose hydroxy groups available for esterification, between two and three are esterified by controlling the amount of acid (degree of 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 tobacco smoke may be added to cigarette filters. The five largest manufactures of filter tow are Hoechst-Celanese and Eastman Chemicals in the United States, Rhodia Acetow in Germany, Daicel and Mitsubishi Rayon in Japan.
The filter may be made from cellulose acetate fibre, paper or activated charcoal (either as a cavity filter or embedded into the cellulose acetate). Macroporous phenol-formaldehyde resins and asbestos have also been used in cigarette filters. The acetate and paper modify the particulate smoke phase by particle retention (filtration), and finely divided carbon modifies the gaseous phase (adsorption). In laboratory testing, filters have been shown to reduce "tar" and nicotine smoke yields up to 50%, with a greater removal rate for certain classes of compounds (e.g., phenols) compared to others—the filters are particularly inefficient at removing gases of very low molecular weight, such as carbon monoxide. In addition, most of these measured reductions occur only when the cigarette is smoked on a smoking machine; when smoked by a human, the compounds are delivered into the lungs regardless of whether or not a filter is used.
Most factory-made cigarettes are equipped with a filter; those who roll their own can buy them from a tobacconist. The near-universal adoption of filters on cigarettes has not reduced harms to smokers and lung cancer rates have not declined.
Filling a given length of cigarette with filter is cheaper than filling it with tobacco.
Cellulose acetate is made by esterifying bleached cotton or wood pulp with acetic acid. Of the three cellulose hydroxy groups available for esterification, between two and three are esterified by controlling the amount of acid (degree of 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 tobacco smoke may be added to cigarette filters. The five largest manufactures of filter tow are Hoechst-Celanese and Eastman Chemicals in the United States, Rhodia Acetow in Germany, Daicel and Mitsubishi Rayon in Japan.
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