GB1561659A

GB1561659A - Tobacco smokefilter

Info

Publication number: GB1561659A
Application number: GB456/79A
Authority: GB
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1975-10-10
Filing date: 1976-10-08
Publication date: 1980-02-27
Also published as: JPS5247998A; ATA750976A; GB1561658A; LU75953A1; SE7611225L; DK453376A; CH586518A5; BR7606740A; ZA766026B; FR2326879A2; BE847125R; AT348909B

Description

PATENT SPECIFICATION

( 11) 1 561659 ( 21) Application No 456/79 ( 22) Filed 8 Oct 1976 ( 62) Divided out of No 1 1 561 658 ( 61) Patent of Addition to No 1 500 922 dated 26 Sept 1977 ( 31) Convention Application No 13171/75 ( 32) Filed 10 Oct 1975 in ( 33) Switzerland (CH) ( 44) Complete Specfiication published 27 Feb 1980 ( 51) INT CL 3 A 24 D 3114 ( 52) Index at acceptance A 2 C 1 E 3 ( 54) TOBACCO SMOKE FILTER ( 71) We, HOECHST AKTIENGESELLSCHA Fr, a body corporate organised according to the laws of the Federal Republic of Germany, of 6230 Frankfurt/Main 80, Postfach 80 03 20, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the

following statement: -

The invention relates to a tobacco smoke filter, especially a cigarette filter, containing cellulosic material.

Such filters are used, for example in cigarettes, to retain to a greater or lesser extent various constituents of the cigarette smoke, such as tar and nicotine, as well as other harmful substances.

Cellulosic material is used in the manufacture of cigarette filters In particular, cellulose acetate is widely used because filters made of this material are inexpensive and their production is simple However, they do not significantly reduce the content of tar, nicotine and other harmful substances in cigarette smoke.

In order to remedy this disadvantage, German Offenlegungsschrift No 2 512 511 proposes a cigarette filter with a cellulosic material which contains at least some modified cellulose or cellulose ether.

Although this filter is selectively highly effective, in particular against tar and nicotine, its manufacture is not particularly advantageous technologically because the active material, modified cellulose or modified cellulose ether, has to be added to the filter carrier material in the form of fine fibres or powder.

The present invention provides a tobacco smoke filter, especially a cigarette filter, comprising at least in part cellulose in the form of paper treated with an organic isocyanate, a higher molecular weight fatty acid, an ester of a higher molecular weight fatty acid, a complex of a higher molecular weight fatty acid with basic chromium chloride or a melamine resin precondensate with a higher molecular weight fatty acid group.

There is advantageously used a creped tissue paper with a weight per unit area of approximately 22 to 45 g/m 2 Paper, advantageously paper the creped tissue of such a weight, may be impregnated with a solution of the treating, otherwise known as modifying, agent in water or an organic solvent and subsequently dried As modifying agents there may be mentioned organic, preferably divalent or polyvalent, isocyanates or higher molecular weight fatty acids, esters of a higher molecular weight fatty acid, complex compounds of a higher molecular weight acid with basic chromium chloride or a melamine resin precondensate having a higher molecular weight fatty acid group This type of modification is explained in detail in German Offenlegungsschrift No 2 515 511.

The "higher molecular weight" fatty acids are acids having at least 14 carbon atoms.

Among the special advantages of the filter, especially as a cigarette filter, according to the invention is its selective filter action for phenol and also for other relatively hydrophilic substances, such for example as methanol, lower aldehydes, ketones and nitriles.

This selectivity is noted especially in filters of paper with cellulose modified by higher molecular weight fatty acid groups The retention capacity for nicotine and tar lies, in addition to the mentioned selective filter action, within the scope of the values determined for untreated papers When smoking cigarettes with the filters according to the invention, there is no untoward increase in the draw resistance for the smoker; the draw reistance of the cigarette remains constant during smoking.

The following examples, in which the percentages are by weight, illustrate the invention.

EXAMPLE 1

A cigarette filter consisting of a paper which is modified by a melamine resin precondensate having a stearic acid group is produced as follows.

A creped web of tissue 120 mm wide and having a weight per unit area of 25-7 g/m 2 is C V ISIZ M-1 L 1 % M( 19) 1.561,659 impregnated with a 1 % strength solution of a trimethylol melamine substituted with stearic acid After removing the solvent and drying at 100 C it shows an increase in weight of approximately 5 % The modification reagent is advantageously prepared by mixing 2-5 1 of a 20 % aqueous emulsion of the substituted trimethylol melamine, 2 '5 1 of aqueous acetic acid ( 40 %o strength) and enough 87 % aqueous propanol to produce a 50 1 stock solution.

EXAMPLE 2

A cigarette filter consisting of a paper modified with a triisocyanate is produced as follows.

A creped web of tissue 120 mm wide and having a weight per unit area of 2517 g/m 2 is impregnated with a 46 % strength solution of triisocyanate in xylene to the extent that after removal of the solvent and drying at 120 C it has increased in weight by approximately % The triisocyanate is obtained by condensing 3 molecules of hexamethylene diisocyanate.

Claims

WHAT WE CLAIM IS:-

1 A tobacco smoke filter comprising cellulose in the form of paper treated with an organic isocyanate, a fatty acid having at least 14 carbon atoms, an ester of a fatty acid 30 which acid has at least 14 carbon atoms, a complex of a fatty acid having at least 14 carbon atoms with basic chromium chloride or a melamine resin precondensate with a fatty acid group having at least 14 carbon atoms 35

2 A filter as claimed in claim 1, which is a cigarette filter.

3 A filter as claimed in claim 1 or claim 2, which comprises cellulose modified by an at least divalent isocyanate 40 4 A filter as claimed in claim 1, substantially as described in either of the Examples herein.

A cigarette, having a filter as claimed in any one of claims 2 to 4 45 ABEL & IMRAY, Chartered Patent Agents, Northumberland House, 303-306 High Holborn, London WC 1 V 7 LH Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon), Ltd -1980 Published at The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.