Smoking article with modified smoke delivery

Abstract

A smoking article (10) comprises a tobacco rod (12) wrapped with a paper wrapper (14), and a patch (16) of material between the tobacco rod and the paper wrapper that extends along the tobacco rod from or near the mouth end (B) to an intermediate point along the rod. The patch has a structure such that it provides a path for smoke from tobacco upstream of the patch to the mouth end that has less resistance to smoke flow than a path through the tobacco under the patch, thus delivering smoke from the upstream part of the tobacco rod to the smoker more efficiently. The patch may also increase the static burn rate of the latter part of the smoking article.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a smoking article with modified smoke delivery.[0002]Smoking articles such as cigarettes comprise a rod of smokable material such as tobacco which is tightly wrapped in a paper wrapper (cigarette paper). A filter unit comprising one or more filter components may be joined to the wrapped tobacco rod using a tipping paper. For a uniform composition of tobacco rod, the smoke that is delivered through the tobacco rod from the burning tobacco, for any given puffing regime, is determined by three main factors: the amount of air drawn in through the coal during puffing (which depends upon the level of ventilation through the cigarette paper); the filtration of the smoke through the remaining unburnt part of the tobacco rod; and the speed of burn of the tobacco rod between puffs (smoulder rate). The smoke delivery from any single puff thus depends on the length of tobacco rod remaining, and for a standard puff volume taken fr...

AI Technical Summary

Benefits of technology

[0006]This structure modifies the smoke flow compared to an equivalent smoking article without a such a patch. Smoke generated from tobacco in the first portion of the tobacco rod is provided with a preferential low resistance path through the smoking article when the smoker draws on the smoking article, so the smoke is delivered more efficiently. This improves the quality of the smoking experience for the smoker. An additional effect is also provided by the patch. The introduction of an open-structured material into the smoking article increases the static burn rate of the smoking article over the portion including the patch. The smoker can thus take fewer puffs from the second portion of the smoking article, thus receiving less smoke and a correspondingly reduced amount of the residues that can accumulate in the tobacco from the consumption of the first portion of the smoking article.

[0012]The patch may comprise at least one burn-enhancer to increase the static burn rate of the smoking article over the length comprising the patch. This can be used to tailor the static burn rate and consequently the number of puffs that can be taken from the latter part of the smoking article.

[0014]The tobacco rod may have a reduced weight of tobacco per unit length under the patch compared to upstream of the patch. This both provides space to accommodate the patch, and further increases the static burn rate of the portion of the smoking article that includes the patch. Any suitable method can be employed to provide such a tobacco rod. For example, the reduced weight may be created by trimming tobacco from the outside of the tobacco rod, or by trimming tobacco from a tobacco bead from which the tobacco rod is to be cut.

[0018]The method may comprise: trimming tobacco from the outside of the rod of tobacco over an area where the patch is to be disposed, thereby creating a reduced weight of tobacco per unit length; and disposing the patch over the rod of tobacco so that the patch covers the area from which tobacco has been trimmed. Alternatively, the method may comprise trimming tobacco from the outside of a bead of tobacco over an area where the patch is to be disposed, thereby creating the reduced weight; cutting a rod of tobacco from the bead; and disposing the patch over the rod of tobacco so that the patch covers the area from which tobacco has been trimmed.

Problems solved by technology

However, the structure of the tobacco rod also plays a part in the delivery of smoke to the smoker, owing to the passage of the smoke through the unburnt portion of the tobacco.

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