Kimberly-Clark Corporation

John H Mathews

Vladimir Hampl, Jr

Donald F Durocher

Charles F Mattina

Mary L DeLucia

The invention is an improved wrapper construction for smoking articles such as cigarettes resulting in a reduced tendency to ignite combustible materials accidentally or carelessly coming into contact with the lit cigarette. The wrapper constructions and smoking articles of the invention have a specially designed structure which causes a cigarette to go out quickly when in contact with a substrate, including many commonly-encountered substrates made of combustible materials. This structure is characterized by a Burn Mode Index ('BMI') as defined for the wrapper of between about 1.5 cm.sup.-1 and 5.0 cm.sup.-1 for a single wrap embodiment. For an alternative double wrapped embodiment, the outer wrap will have a BMI in the range of from about 2.0 cm.sup.-1 to about 40 cm.sup.-1 depending on the BMI of the inner wrap which may vary between about 0.1 cm.sup.-1 to 4.0 cm.sup.-1. The preferred amount of burn promoter is at least 15 mg anhydrous potassium citrate per gram of bone dry paper or stoichiometrically equivalent amounts of other burn promoting salts. Preferred substrate embodiments include paper made from flax or other cellulosic fibers, treated with elevated amounts of an alkali metal burn promoter such as alkali metal salts of carboxylic acids, especially potassium salts. In contrast to other attempts, these results are obtained without a significant sacrifice of desired taste and smoke deliveries, for example, without unacceptable increases in puff count or significant increases in delivered tar and carbon monoxide. Wrapper constructions and smoking articles of this invention may be manufactured using conventional cigarette paper processes and equipment.

Reduced ignition proclivity smoking article wrapper and smoking article

Sheet material especially useful in forming wrappers for smokable articles such as cigarettes that results in reduced sidestream smoke. The sheet is formed by applying to a cellulosic web an amount of an alkali metal salt greatly in excess of the amounts of such materials previously used as burn enhancers. The cellulosic material may be flax fiber or other natural cellulosic fibers conventionally used for such wrappers. Examples of salts include the sodium or potassium salts of acids such as carbonic, formic, acetic, propionic, malic, lactic, glycolic, citric, tartaric, fumaric, oxalic, malonic, succinic, nitric, and phosphoric. The composition can be applied by any conventional method such as coating, dipping, impregnating, printing, and the like. For example, at least about 6% by weight of potassium citrate is needed to obtain the benefits of the invention, and preferably an amount in the range of from about 12% to about 16% by weight. When such papers are used as cigarette wrappers, they effect a reduction of the total particulate matter in sidestream smoke of up to about 50% without serious deterioration of other desirable properties.

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Lee, MA, United States of America

John H Mathews