NZ248453A - Filter, filter material or tobacco product containing metal borate - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £48453 2 4* 81:53 = fr.or.ty Date(s): ....

Cortipiets Specification Filed: .9-S?:?.'?.^* ' rh^: foth&S.k*,.

Publiccj.on Date: . .?.?.P.CT 1994 P^O- J:i r;T:', no mmm N.Z. No.

NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION ENHANCING THE PERCEIVED STRENGTH OF TOBACCO SMOKE We, ROTHMANS INTERNATIONAL TOBACCO LIMITED, a British Company of 15 Hill Street, London W1X 7FB, England do hereby declare the invention, for which we pray that a patent may be grants J to us. and the method by which it is to be performed, to be particularly described in and by the following statement:- lA ENHANCING THE PERCEIVED STRENGTH OF TOBACCO SMOKE This invention relates to enhancing the perceived strength of tobacco smoke, and to a tobacco product and/or filter material for use for that enhancement.

According to the present invention we enhance the perceived strength of smoke from a tobacco product. This aim has been known from, e.g., GB-A-2228399.

There, we added magnesium (hydr)oxide to a tobacco product. This has proved to be less than ideal since the deposited magnesium (hydr)oxide tends to be displaced in the smoke current.

In the present invention we add one or more borates of metals to the tobacco product and/or filter material for use therewith.

Borates have been added to smoking articles before. See US-A-4516589 where phosphates and borates (1 to 2%) are used together to coat filter-material bundles before they are pyrolyzed. The purpose of the coating appears to be to increase the strength of zhe pyrolyzed fibres, but may be to render the fibres non-combustible (borates are known to be fire-suppressants) . See also GB-A-1299641 and 1299296 where (amongst many other inorganic materials) metal borates 6 2 are suggested as an excipient.

For our purposes the metal borate can be incorporated into the tobacco product which is to be smoked or, preferably, it can be incorporated in filter 5 material which is used to filter the smoke produced by that tobacco product. Such lilter material could be in the form of a filter tip for use on a cigarette or as a filter insert for use, for example, in a pipe in which the tobacco product is smoked.

We have found that the addition of a metal borate to a smoking article enhances the strength of the smoke as perceived by the smoker since the ratio between nicotine-free dry particulate matter ("NFDPM") and nicotine received by the smoker is altered in 15 favour of the nicotine.

A preferred form of the additive is sodium tetraborate.

We may add 5% or preferably upwards of 10% by v/eight of the metal borate related to the treated mass 20 e.g. the filter material or the tobacco product: a maximum percentage by weight will be of the order of 4 0%. Particularly preferred is 10% to 20% by weight of sodium tetraborate decahydrate.

The additive can be added in the form of a dry 25 powder or solid, or in solution in a suitable solvent, for example water or alcohol.

Alternatively, the additive can be added in the form of a suspension in a suitable liquid.

If desired, the additive can be added in the form of a solution in water to any filter which is to be used with a smoking tobacco or which is to be used in the manufacture of cigarettes or cigars. Such filters are commonly formed from fibrous tows or webs of appropriate materials, for example cellulose acetate, paper or polypropylene.

The additives may be applied to pipe tobaccos or to the tobaccos used in the manufacture of cigars or cigarettes. If desired the additive may be incorporated into reconstituted tobacco sheet during the manufacture of the latter from tobacco, waste tobacco or stems. Hereinafter tobacco and tobacco products such as reconstituted tobacco sheets will be referred to as "tobacco products" . The additives are particularly valuable in enhancing the perceived strength of flue-cured tobacco products because the smoke of these has a comparatively low pH (high acidity).

The invention also includes a smoking article including a tobacco product or filter material as set forth above.

The invention can be performed in many ways but one embodiment will now be described.

I 4 ' ~r c -* ^ - - j 4 Sodium tetraborate decahydrate was applied at a level to yield 40mg/filter in a solution of water to paper filter segments, originally weighing 170mg on average, destined for a dual filter with longitudinally 5 abutting paper and cellulose acetate zones. Tip ventilated, filter cigarettes were subsequently manufactured from untreated filters (control) and from the treated filters, with a cellulose acetate zone at the mouth end.

The quantity of sodium tetraborate in the treated paper filter segments, now weighing 210 mg on average, was determined from the increase in sodium content, measured using atomic absorption spectrometry. The pH of a 2% solution in water of the 'tar' produced 15 by smoking cigarettes under standard conditions (3 5ml puffs of two seconds duration at a frequency of one puff per minute) was measured using a pH meter fitted with a glass electrode. The values obtained for the cigarettes were as follows: Na2B407 10H20 Content pH (mg) Nil (Control) 6.8 40mg* 7.3 *4 0mg of a total weight of 210mg = 19% by weight of the J paper filter segment.

A panel of smokers found that the perceived strength of the smoke from the treated cigarettes was increased relative to the control.

Smoke chemistry results from these cigarettes were as follows: Na2B407 10H20 Content NFDPM NICOTINE NFDPM/NICOTINE 0 (mg) (mg/cig) (mg/cig) ratio Nil (Control) 5.8 0.59 9.8 4 0mg 5.5 0.63 8.7 2484 6

Claims (11)

WHAT WE CLAIM IS:

1. A filter, filter material or tobacco product having as an additive a metal borate in the range 5-39% by weight of the treated mass.

2. A filter, filter material or tobacco product according to claim 1 wherein the metal borate is an alkali metal borate.

3. A filter, filter material or tobacco product according to claim 2 wherein the metal borate is sodium tetraborate decahydrate.

4. A filter, filter material or tobacco product according to any one of the preceding claims wherein the additive content is 10% to 39% by weight.

5. A smoking article incorporating a filter, filter material or tobacco product according to any one of the preceding claims.

6. A smoking article according to claim 5 whose tobacco is a flue-cured tobacco.

7. A smoking article according to claim 5 or claim 6 wherein the additive is solely in a filter thereof.

8. Use of a filter, filter material or tobacco product according to claim 1 to enhance the perceived strength of tobacco smoke in a smoking article, by increasing the ratio of nicotine to nicotine-free dry particulate matter in the smoke. , 248 453

9. Use according to claim 8 wherein the alkali metal borate is sodium tetraborate decahydrate.

10. A filter, filter material or tobacco product according to claim 1 substantially as herein described or exemplified.

11. A use according to claim 8 or 9, substantially as herein described or exemplified. ROTHMANS INTERNATIONAL TOBACCO By Their Attorneys HENRY HUGHES Per: .IMITED