EP0565359A1

EP0565359A1 - Wrapper with bands of reconstituted tobacco sheet for smoking articles

Info

Publication number: EP0565359A1
Application number: EP93302732A
Authority: EP
Inventors: Edward B. Sanders
Original assignee: Philip Morris Products Inc; Philip Morris USA Inc
Current assignee: Philip Morris Products Inc; Philip Morris USA Inc
Priority date: 1992-04-09
Filing date: 1993-04-07
Publication date: 1993-10-13
Also published as: JPH0610299A

Abstract

A wrapper for controlling burn rates of smoking articles 10 is provided. The wrapper 100 is constructed from a porous paper base wrapper 20 with one or more bands 30 affixed to the base wrapper and located at selected intervals along the base wrapper. The bands are comprised of non-porous reconstituted tobacco. The regions of the smoking article at which the bands are located burn at a different rate than the remainder of the base wrapper.

Description

Background of the Invention

This invention relates to wrappers for smoking articles such as cigarettes and especially to a wrapper construction in which burn rate is controlled.
It is beneficial to make smoking articles which have a reduced burn rate if not drawn upon by the smoker but which will taste, feel, look, smell and burn like a conventional cigarette when drawn upon by the smoker at normal intervals. It is recognized by those skilled in the art that the construction of the wrapper influences the behavior of the smoking article during smolder. Therefore, construction of a wrapper in which burn rate of the smoking article is controlled is advantageous.
Modification of wrappers for smoking articles for the purpose of controlling burn rate has been described previously. For example, it is known that by affixing small bands of a non-porous paper to normal cigarette paper, the cigarette formed therefrom will have a lesser tendency to continue burning when the coal reaches the band. United States patent 4,739,775 describes such a cigarette paper.
Affixing bands of non-porous paper, which contain cellulose, to a cigarette wrapper presents the problem of increasing the cellulose pyrolysis products from the ignited cigarette. It is known that the pyrolysis products from cellulose are often subjectively undesirable to smokers. These products may have an undesirable effect upon, for example, taste. Consequently, it is desirable to produce a wrapper construction for smoking articles such as cigarettes that would control burn rate without adversely affecting the subjective impact of the smoking article to the smoker.

Summary of the Invention

It is an object of this invention to provide a wrapper construction for smoking articles such as cigarettes in which the burn rate of the smoking article is controlled.
It is an object of this invention to provide such a wrapper construction without slowing the speed at which smoking articles are manufactured.
It is also an object of this invention to provide the wrapper construction without adversely affecting the properties of the smoking article which are desirable to smokers.
It is a further object of this invention to provide an economical use for scraps of tobacco.
In accordance with the invention, a wrapper and smoking article,such as a cigarette, are provided in which the burn rate of the article is controlled. The wrapper is formed from a web of porous base paper having circumscribing bands cut from a sheet of reconstituted tobacco, such as BL sheet, affixed to it. Reconstituted tobacco sheet is typically a slow burning material which is non-porous. The bands of reconstituted tobacco sheet are affixed to the base in selected regions by using a standard adhesive. Thus, the burn rate of the smoking article is controlled because the bands of reconstituted tobacco sheet burn at a different rate than the remainder of the porous base wrapper. The use of bands cut from sheets of reconstituted tobacco provides burn rate control while maintaining the desirable properties of the smoking article.

Brief Description of the Drawings

FIG. 1 illustrates a cigarette made in accordance with the wrapper construction of the present invention.
FIG. 2 illustrates a paper wrapper with bands according to the present invention affixed to it at selected intervals.
FIG. 3 is a sectional view of the paper wrapper of FIG. 2 taken along lines 3-3.

Detailed Description of the Preferred Embodiment

FIG. 1 illustrates an embodiment of cigarette 10 manufactured according to the present invention. Cigarette 10 is comprised of base wrapper 20, bands 30 affixed to base wrapper 20 at selected intervals and tobacco column 12. In order to obtain the desired levels of burn rate control of cigarette 10, bands 30 may be affixed to base wrapper 20 at any interval desired. Preferably, bands 30 are 5-10 mm wide and are spaced 15-20 mm apart. It has been found that the use of 4 or 5 bands is preferable.
The manufacture of paperfor use as wrappers for smoking articles such as cigarettes is generally known by those skilled in the art. In general, such paper is of a porous type. In order to obtain controlled burn rates of the smoking article without adversely affecting the properties of the article which smokers find desirable, bands 30 are cut from sheets of reconstituted tobacco.
There are several different types of reconstituted tobacco sheet which are suitable for use in the present invention. One variety of reconstituted tobacco sheet is known as BL sheet. BL sheet is formed by digesting scraps of tobacco along with other ingredients into a slurry. The slurry is held in a tank for a predetermined period of time. The slurry is then poured onto a continuous steel belt which is passed through a series of dryers. Thus, the moisture in the slurry is driven off by the application of heat. The BL sheet is removed from the belt after drying.
Two other varieties of reconstituted tobacco sheet which are made in a similar manner are cast sheet and cast leaf. The cast sheet process is similar to the BL sheet process but the tobacco slurry is generally not held in a tank during processing. The cast leaf process involves mixing tobacco dust particles, a binder and other agents such as humectants or preservatives in an aqueous media to form a slurry. Air trapped within the slurry is removed. The slurry is then cast onto a continuous stainless steel belt or other supportive device where it is dried to form a reconstituted tobacco sheet. The sheet is removed after drying. The cast leaf process is more particularly described in copending, commonly assigned application Serial Number 07/ (PM 1415), "Reconstituted Tobacco Sheets And Methods For Producing And Using The Same."
Yet another variety of reconstituted tobacco sheet is RL sheet. RL sheet is formed by a process similar to paper making in which a tobacco slurry is fed over a Fourdrinier wire arrangement. The moisture in the slurry is driven off by letting it flow through the wire arrangement while the slurry remains on top of the wire arrangement.
Each type of reconstituted tobacco sheet is suitable for use in the present invention. BLsheet is, however, preferred because the resulting strip is less porous than the other varieties of tobacco sheet. Therefore, the use of BL sheet will result in greater control of the burn rate of the cigarette in the region of the band due to its low porosity.
FIGS. 2 and 3 more clearly illustrate bands 30 affixed to base wrapper 20.
Attachment of bands 30 to base wrapper 20 may be either to the inner surface of base wrapper 20 or to the outer surface of base wrapper. However, attachment to the inner surface of base wrapper 20 is preferable in order to maintain a more pleasing appearance of the cigarette. Bands 30 may be affixed to base wrapper 20 using known adhesives, for exam- pie polyvinyl acetate.
It will be apparent to those skilled in the art that the invention described herein can be practiced by other than the embodiments described above, which are presented for the purpose of illustration and not of limitation and are limited only by the claims which follow.

Claims

1. A wrapper for smoking article comprising:

a base wrapper (20); and

a circumscribing band (30) comprising reconstituted tobacco material, the band being affixed to the base wrapper, whereby the smoking article has a controlled burn rate when burning in the region of the band.

2. A wrapper according to claim 1 wherein the base wrapper (20) is of porous paper.

3. A wrapper according to claim 1 or 2 wherein the reconstituted tobacco material is BL sheet, cast sheet, cast leaf, or RL sheet.

4. A wrapper according to claim 1, or 3 comprising a plurality of bands (30).

5. A wrapper according to claim 4 comprising 4 or 5 bands (30).

6. A wrapper according to claim 4 or 5 wherein the plurality of bands (30) are affixed to the base wrapper at intervals of 15-20 mm.

7. A smoking article comprising a column (12) of tobacco contained in a wrapper according to any preceding claim.