CA2319855A1 - Method for causing self-extinguishment of cigarettes - Google Patents

Abstract

This invention provides a method for controlled free burn rate and reduced ignition propensity that leads to a self-extinguishment of a cigarette. The cigarette is comprised of a wrapper which encloses a body of tobacco with micro-encapsulated water particles distributed evenly throughout. The micro-capsules being ruptured by the advancing heat of the burning coal provide the means for reduced ignition propensity and eventual self-extinguishment of the cigarette when the cigarette is not actively being smoked.

Description

Specifications This invention relates generally to self extingulshment of a cigarette at any point along the cigarette. In this invention, self extinguisFiment of a cigarette relies on the cumulative latent heat of hundreds of self contained, heat-sensitive, water-filled micro-capsules embodied in the tobacco to remove sufficient heat from the burning coal that leads to self extinguishment at any point along the length of the burning cigarette. Prior to the present invention there has not been any invention, disclosure nor patent where this is evidenced. Prior art is noted by Lappin, J. Jr. U.S. Pat. No. 3,985,143 in which enclosed water from a large, unitary plastic sack at a single, pre-determined location ruptures, and likewise by Seatts, William U.S. Pat. No 4,436,101 in which enclosed pressurized water from a unitary vessel located in the filter tip is ejected into the burning tobacco. Prior art referenced indicate clear deficiencies in that they require the burning coal to be in the vicinity of the enclosing vessel. They cannot be effectively relit, and do not feature a controlled free burn rate. Accordingly, prior art fails to suggest or disclose any of the objects or benefits of the said invention.
It is the object of the invention to provide a cigarette with a means for causing self extinguishment of the cigarette after a predetermined time and still be an acceptable cigarette for smoking pleasure. A fiuther object of this invention is to provide a method for limiting the incendiary quality of cigarettes and said method can easily be incorporated into the present cigarette manufacturing process. A filrther object of the Invention Is to provide a cigarette which consumes less tobacco when compared to a conventional cigarette based on the same number of puffs.
The above objects are achieved by the cigarette construction having a body of tobacco enclosed by a combustible wrapper, the said tobacco having generally, evenly distributed within it throughout the entire length of the said tobacco portion, micro-encapsulated water particles. The said micro-capsules being. ruptured by the heat of the advancing coal, provides sufficient moisture to lead to self extmguishment of the cigarette when not actively being puffed. The cigarette, when being smoked with the normal puff rate of 1 puff per minute provides sufficient heat to vaporize the water micro-particles and continue a free burn. Self extinguishment time can therefore be pre-determined by adjusting the micro-capsule/tobacco ratio.

A feature of the invention is that the micro-encapsulated water particles in accordance with the invention can have certain desirable additives incorporated into the micro-capsule such as humectants that would be released upon rupture and improve flavour and overall quality of the cigarette.
The said micro-capsules are of the type that are commonly commercially produced and supplied by various industrial suppliers. The microcapsule coating may assume any of a number of selected forms but in each case the cigarette will be such that the smoke drawn by the user through the cigarette will not be appreciably impeded. The material forming the microcapsule is preferably under tension so that when it is ruptured the water therein will be completely released to instantly impinge on the tobacco at that location.
The invention is applicable to the commonly employed cigarette structure to which the conventional tobacco filler is wrapped in a paper or a similar combustible wrapper. The invention is also applicable to cigarettes of various lengths, with or without filters, or where combustible materials other than tobacco are used..
In accordance with the invention, the cigarette has water-filled micro-capsules dispersed throughout the entire tobacco containing portion. The invention depends mainly on the feature of the heat sensitive micro-capsule rupturing in response to the heat of advancing coal and releasing the water content of the micro-capsule. When the cigarette is not actively being puffed, the said released water provides sufficient latent heat of evaporation to cool the burning coal and effectively lead to extinguishment of the cigarette.
The rupturing of the micro-capsule and further release of its water content is not obvious to the smoker and does not visually alter the cigarette. Further, the extinguished cigarette can be easily relit.
The micro-capsules will ordinarily and preferably be made of a lipid, polymer or similar water-proof, heat sensitive material. The individual water-filled containers may be made through the use of common technologies such as are used in the micro-encapsulation industry for the creation of liquid-filled micro-capsules or micro-spheres, sometimes referred to as prills.
While a number of modifications of water-filled micro-capsules have been disclosed herein, it will be understood that the invention is not limited thereto but encompasses any form of liquid-filled micro-capsules in which the container material is capable of being ruptured by the advancing burning tobacco, or is capable of being ruptured by the heat created by the advancing burning tobacco and at the same time, its cross-sectional area will not adversely affect the passage of smoke thereby as the cigarette is being smoked by the user.
When the term micro-capsule is used in the claims as representing the form of the material of the liquid cod, ft is to be understood that this is representative of any type of micro-capsule that is smaller than 4000 micron in diameter and is composed of any suitable waterproof material adapted to hold the liquid and to be ruptured by the advancing burning tobacco.
The drawing illustrates in figure 1 the embodiment of the invention, in which a cigarette comprising of a combustible tube (4) and a filter (2) and containing conventional shredded tobacco (6) enclosed therein, will have commercially obtained micro-particles (8) comprising of a solidified lipid and fire-retardant liquid emulsion generally evenly distributed throughout the tobacco portion of the cigarette.

Claims (4)

1. In a cigarette comprised of a combustible tube with tobacco enclosed therein, this is a method for reducing the free burn time and causing self-extinguishment of a cigarette when the said cigarette is not actively smoked, which comprises of micro-encapsulated particles generally, evenly distributed in sufficient number throughout the length of the tobacco portion of the cigarette.

2. This is a method as defined in claim 1, in which said micro-capsules being of the type that are commercially manufactured and obtained, and being in the form of spherical particles with an average diameter not more than 4000 microns.

3. This is a method as defined in claim 1, in which said micro-capsules being generally, evenly distributed in sufficient number throughout the length of the tobacco portion so that the smoke will not be impeded, nor will the cigarette be extinguished should the cigarette be actively smoked.

4. This is a method as defined in claim 1, in which said micro-capsules are comprised of a solidified lipid and fire-retardant liquid emulsion capable of being ruptured by the heat of the advancing burning coal.