WO2010122382A1

WO2010122382A1 - Cigarette filter

Info

Publication number: WO2010122382A1
Application number: PCT/IB2010/000136
Authority: WO
Inventors: Johannes Marthinus Jacob Kruger
Original assignee: Johannes Marthinus Jacob Kruger
Priority date: 2009-04-23
Filing date: 2010-01-27
Publication date: 2010-10-28

Abstract

A cigarette filter (1 ) is provided that includes natural cotton fibres as a filter medium and natural structural fibres that are derived from the leaves or stalks of naturally occurring plants as opposed to being formed in a boll in a seed capsule with the cotton fibres being present in an amount of from 15 to 85% by weight, preferably about 25% by weight. The fibres are preferably cut into short lengths of from 2 to 10 mm with a preferred length of cotton fibres being about 3 mm and a preferred length of structural fibres being about 5mm. The structural fibres may be selected from those of one or more of sisal, jute, hemp, flax, kernaf, bamboo, coir, raffia, ramie, and suitable straws or grasses.

Description

CIGARETTE FILTER

FIELD OF THE INVENTION

This invention relates to a cigarette filter and, more particularly, a cigarette filter that is more environmentally friendly than cigarette filters commonly made of fibrous synthetic materials, typically cellulose acetate, that does not decompose readily.

It is to be understood that the term "cigarette filter" as used in this specification is intended to include all filters that are used for the purpose of filtering tobacco smoke for inhalation purposes irrespective of the form in which the tobacco may exist such as in a cigarette, cigarillo, or cigar, and the term is further intended to include disposable filters for installation in cigarette or cigar holders, tobacco-pipes and the like.

BACKGROUND TO THE INVENTION

It is common practice to use cigarette filters to reduce the ill effects of tobacco smoke by reducing the quantity of vapours, condensate, nicotine and other tobacco combustion products that reach the mouth, throat and lungs of a smoker. Of course, it is undesirable to remove too much of the components that provide flavour and satisfaction to the smoker, otherwise the purpose of smoking would be destroyed. There is, accordingly, a balance to be achieved when filtering tobacco smoke.

Cigarette filters made of fibrous cellulose acetate have been developed over many years and are currently regarded as providing a satisfactory balance in removal of harmful combustion products whilst providing satisfactory taste and satisfaction to a smoker. However, such cigarette filters are slow to degrade and accordingly present a considerable pollution problem worldwide.

Cotton, being a natural fibre that degrades satisfactorily, has been proposed in the past as a filter medium. However, it has not been successfully commercialised, apparently for one or both of two reasons. The one reason is that cotton fibres compacted into a filter appear to applicant to upset the balance indicated above. The other reason is that it appears that a cotton fibre filter has insufficient integrity in a bulk form.

United States patent 4,197,863 describes the use of a cotton cigarette filter in which the fibres of the cotton are orientated generally circumferentially with respect to the cigarette axis and wherein one or more other separate filters are located next to the cotton filter. The proposal is complex and costly and does not appear to overcome a basic drawback of a cotton filter.

United States patent 3,946,748 describes the use of rolled up cotton fabric as a filter in a cigarette holder that is presumably aimed at avoiding a basic drawback of an unwoven cotton filter. This arrangement too is complex and costly.

OBJECT OF THE INVENTION

It is an object of this invention to provide an environmentally friendly cigarette filter that includes natural cotton as at least a part of its filter medium and that may be configured to overcome, at least to some extent, the disadvantages indicated above whilst achieving a suitable balance in removing harmful combustion products and allowing adequate taste and effect to remain. SUMMARY OF THE INVENTION

In accordance with one aspect of this invention there is provided a cigarette filter that includes natural cotton fibres as a filter medium, the cigarette filter being characterised in that the cotton fibres are admixed with natural structural fibres (as herein defined) with the cotton fibres being present in an amount of from 15 to 85% by weight.

Further features of the invention provide for the cotton fibres to represent 20 to 50% by weight of the mixed fibre filter, preferably about 25% by weight; for the cotton fibres and structural fibres to be cut into short lengths; for the cotton fibres to be cut into short lengths of about 2 to 10 mm, preferably 2 to 5 mm, and most preferably an average length of approximately 3 mm; for the structural fibres to be cut into short lengths of from about 2 to 10 mm, preferably 3 to 8 mm; and most preferably an average length of about 5 mm; for the structural fibres to be worked to soften and possibly reduce the thickness of the fibres; for the filter to be formed from a compressed nonwoven mat of the mixed natural fibres; and for each filter to comprise about 0.15 to 0,3 grams and preferably about 0.2 grams of the mixed natural fibre material.

In spite of the novel composition of the cigarette filters they are incorporated into a cigarette, or formed into any other required format, in substantially conventional manner and a cigarette including same may be composed of a tube of suitable paper containing packed finely cut tobacco over the major part of its length with a filter tip containing the filter of the invention at its one end. The filter of the invention is preferably contained within a natural paper filter tip that is biodegradable in order to provide an entirely biodegradable filter assembly. The outer end of the filter may be covered with a suitable disk of material such as a cotton wool or natural filter paper to provide an attractive appearance, should this be desired. In accordance with a second aspect of the invention there is provided a method for the production of a cigarette filter as defined above, the method comprising the steps of producing a slurry of subdivided fibres of cotton in in a fluid such as water; producing a separate slurry of subdivided natural structural fibres in the same fluid; mixing the two slurries together in proportions appropriate to the formation of the desired mixed natural fibre having the required proportion of cotton fibres; forming a nonwoven mat of fibres from the mixed slurry; processing the mat as may be necessary to remove fluid therefrom; and forming cigarette filters from the mat by cutting and compressing the mat appropriately.

Is to be understood that in this specification the term natural structural fibres is intended to mean suitable fibres that are derived from the leaves or stalks of naturally occurring plants as opposed to being formed in a boll in a seed capsule as in the instance of cotton. Typically the natural structural fibres would be derived from any one or more of sisal, jute, hemp, flax, kernaf, bamboo, coir, raffia, ramie, and suitable straws or grasses. At the present stage of development, however, only sisal has been tested as a natural structural fibre. It is, however, envisaged that one or more other natural structural fibres could be employed in place of sisal or could be employed to replace a part of the sisal.

In order that the invention may be more fully understood one embodiment thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:-

Figure 1 is a partially broken away isometric view of a cigarette having a filter according to the invention; Figure 2 is an isometric view of a disposable filter for use in a permanent smoking accessory such as a cigarette holder or tobacco pipe; and,

Figure 3 is flow diagram illustrating one method of producing a cigarette filter according to the invention.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

In one embodiment of the invention that is given by way of example only, a cigarette filter (1) is made up of 25% by weight of natural cotton fibres and 75% by weight of natural structural fibres, in this instance, sisal fibres. The cigarette filter may be incorporated in a cigarette (2) of conventional construction with finely cut tobacco (3) being enclosed within a tube of suitable paper (4) with the tobacco extending over the major part of its length and a filter tip (5) containing the filter (1) of the invention at its one end. The filter tip used in the application of this invention is preferably of a natural paper so that the entire filter assembly is of a biodegradable nature.

Each filter is typically formed from about 0.2 grams of the mixed natural fibre material. In order to provide an attractive appearance of the visible end of the filter, a disc (6) of a suitable material such as cotton wool or a natural filter paper could be provided at the outer end, if required.

In this embodiment of the invention the cigarette filter is made by a method that is depicted in Figure 3. The method of production of the cigarette filters includes the steps of preparing natural cotton and chopping it up into short lengths having an average length of about 3 mm in a preparation step (10), and thereafter producing a slurry of subdivided fibres of cotton in water in a step indicated by numeral (11). Sisal fibres, being the natural structural fibres used in this example, are separately softened in water and then hammered in order to reduce the thickness of the fibres and soften them further in a preparation step indicated by numeral (12). It is to be mentioned that the necessity of working of the natural fibres by hammering them has not been fully researched and it may turn out that no working is desirable or that working of a different type is preferable.

The sisal fibres are then chopped up into short lengths having an average length of about 5 mm in a step indicated by numeral (13) and a slurry of subdivided sisal fibres in water is prepared in a step indicated by numeral (14).

Appropriate quantities of the slurry of cotton fibres and the slurry of sisal fibres are then mixed in a step indicated by numeral (15) and the mixture is floated onto a suitable drainage surface such as a mesh at a step indicated by numeral (16) to form a mat. The mat is then dried and either immediately processed into elongated rolls of a diameter corresponding to the diameter of the finished cigarette filter, or the mat is temporarily stored in large rolls (17) pending formation of the cigarette filters by cutting and rolling short strips of the mat to form the diameter of the cigarette filter.

Tests conducted to date on filters that were made as described above indicate that a filter having a density and strength comparable to that of a standard synthetic cellulose acetate filter can be produced. The draw through the filter and the residual tobacco combustion products passing through the filter are similar to synthetic cellulose acetate filters.

As indicated above, and as illustrated in Figure 2, disposable filters (30) can be produced in exactly the same way and packaged as may be required to sale. It is to be noted that the so-called delivery of condensate and nicotine may be varied by varying the amount of cotton in the mixture with more cotton being associated with a lower delivery of condensate and nicotine.

It was also noted that the filter is self extinguishing and burns to a lesser extent than a synthetic cellulose acetate filter.

Tests as regards decomposition of the filter were carried out and a discarded filter with a small portion of unburned tobacco was buried under 6 cm of soil together with a comparative standard filter. After three weeks it was noted that the filter according to this invention had commenced decomposing whilst the comparative standard filter showed no signs of decomposition at that stage.

It will be understood and numerous variations may be made to the example described above without departing from the scope hereof. In particular, the composition of the mixture of fibres can vary widely within the limits set out above and it is also envisaged that other structural natural fibres can be employed to partially or totally replace the sisal content of the filter described.

Claims

CLAIMS:

1 A cigarette filter (1) that includes natural cotton fibres as a filter medium, the cigarette filter being characterised in that the cotton fibres are admixed with natural structural fibres (as herein defined) with the cotton fibres being present in an amount of from 15 to 85% by weight

2 A cigarette filter as claimed in claim 1 in which the cotton fibres represent 20 to 50% by weight of the mixed fibre filter

3 A cigarette filter as claimed in claim 2 in which the cotton fibres represent about 25% by weight of the mixed fibre filter

4 A cigarette filter as claimed in any one of the preceding claims in which the cotton fibres and structural fibres are cut into short lengths

5 A cigarette filter as claimed in claim 4 in which the cotton fibres are cut into short lengths of from 2 to 10 mm

6 A cigarette filter as claimed in claim 5 in which the cotton fibres are cut into short lengths having an average length of approximately 3 mm

7 A cigarette filter as claimed in any one of claims 4 to 6 in which the structural fibres are cut into short lengths of from about 2 to 10 mm

8 A cigarette filter as claimed in claim 7 in which the structural fibres are cut into short lengths of from 3 to 8 mm

9 A cigarette filter as claimed in claim 8 in which the structural fibres are cut into short lengths having an average length of about 5 mm

10. A cigarette filter as claimed in any one of the preceding claims in which the structural fibres are worked to soften and possibly reduce the thickness of the fibres.

11. A cigarette filter as claimed in any one of the preceding claims in which the structural fibres are selected from those of one or more of sisal, jute, hemp, flax, kernaf, bamboo, coir, raffia, ramie, and suitable straws or grasses

12. A cigarette filter as claimed in any one of the preceding claims in which the filter is formed from a compressed nonwoven mat of the mixed natural fibres.

13. A cigarette filter as claimed in any one of the preceding claims in which each filter comprises about 0.15 to 0,3 grams of the mixed natural fibre material.

14. A cigarette having a cigarette filter as claimed in any one of the preceding claims.

15. A method for the production of a cigarette filter as claimed in any one of claims 1 to 13 comprising the steps of producing a slurry of subdivided fibres of cotton in a suitable fluid; producing a separate slurry of subdivided natural structural fibres in the same fluid; mixing the two slurries together in proportions appropriate to the formation of the desired mixed natural fibre having the required proportion of cotton fibres; forming a nonwoven mat of fibres from the mixed slurry; processing the mat as may be necessary to remove fluid therefrom; and forming cigarette filters from the mat by cutting and rolling up the mat appropriately.