DE1792226A1 - Process for the treatment of filter material for tobacco smoke - Google Patents

Description

Nuremberg, August 7, 1968 20/45

BRITISH-AMERICAN TOBACCO COMPANY LIMITBD, Westminster House, 7 , Millbank, London, SWI, England

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"Process for the treatment of filter material for tobacco smoke"

The invention relates to a method for treating fibrous, thread-like or sheet-like filter material for tobacco smoke.

Tobacco smoke contains a particle phase in which the less volatile components of tobacco smoke are largely contained in solid or liquid form, as well as a vapor phase in which the more volatile components are present as vapors or oases mixed with the so-called M permanent gases.

Filters for tobacco smoke are often made of filiform or leaf-shaped Material that retains the particle phase through a normal filter process. It is common to have additional filters in such filters Introduce substances to their retention effect against parts of the vapor phase or against special compounds contained therein to improve. Such substances are usually compounds that prevent the retention of the less pleasant ones contained in tobacco smoke Ingredients that affect the oesohmaok of the filtered Adversely affect smoke.

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These less pleasant components of tobacco smoke include the more volatile acidic constituents «whose presence is undesirable ε-a can, such as hydrogen sulphide, st off compounds and hydrocyanic acid.

The invention is based on the object of creating filters with the aid of which hydrogen sulfide compounds and hydrocyanic acid are largely used can be removed from the smoke of burning tobacco.

This object is achieved according to the invention in that a fiber, thread-like or sheet-like filter material is treated with a finely divided zinc-containing powder and this powder through a underwater high-energy atomization process is generated.

The zinc containing powder is preferably with the help of electrical Spark between two zinc electrodes immersed in water. In this case, the finely divided, zinc-containing Powder in the form of an initially gray-black suspension in distilled Receive water that changes color and becomes light gray when standing. This powder can contain about 90 # zinc.

The powder is applied to the filter material in the form of an aqueous suspension by dipping, spraying or coating in such a way that ultimately, after drying, an increase in weight of up to 10% is achieved based on the weight of the filter material. Even small order quantities are effective, while orders of over £ 10 are faced with practical difficulties. Preferably, an order is selected that has a weight increase of about 2 to 5 or 6 * «tqplqpgj ₅

17 ^ 226

Sin embodiment of the inventive production of a aqueous suspension of a finely divided zinc-containing powder is described in more detail below with reference to the drawing. It shows:

Pig. 1 a schematic representation of a spot erosion apparatus

for the preparation of the suspension, and FIG. 2 shows a circuit diagram of this apparatus.

The apparatus according to Pig.l has a stationary zinc electrode 1 in Shape of a large flat plate and a movable electrode 2

.on
in the form of a thin rod which is clamped in the soft iron core 3 of a magnet. The two electrodes 1, 2 are brought into contact with one another 2 cm below the surface of a tub 5 filled with distilled water of relatively low conductivity. The weight of the movable electrode 2 and the magnetic core 3 is balanced by an adjustable counterweight 6 so that a low tensile force of the magnet 4 on the magnetic core is sufficient to separate the two electrodes from one another.

According to the circuit diagram shown in FIG. 2, the circuit for the electrodes 1, 2 and for the magnet 4 is fed with direct current from an alternating current with 14o volt voltage via a full-wave rectifier 8, the electrode 2 being connected to the positive pole. An 8 microfarad capacitor 9 is connected in parallel to electrodes 1, 2, which in turn are connected in series with this capacitor. A variable series resistance Io and variable shunt resistances 11, 12 with 2oo or 155 and 45 ohms are provided for the controllable setting of the current flowing through the magnet coil 4.

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As soon as the circuit is closed, current flows through the electrodes 1,2 by the magnetic coil 4. The resulting attraction of the magnetic core 3 lifts the movable electrode 2 and thereby interrupts the contact between the two electrodes »the capacitor charges quickly up to its discharge voltage and then discharges at a maximum distance between the electrodes 1, 2 over them and creates the spark you want. In the meantime, the magnet coil is essentially de-energized as a result of the separation of the electrodes, so that the magnetic core j5 is no longer attracted, the electrode 2 comes down and comes back in contact with electrode 1. The discharge of the capacitor 9 stops, the solenoid is re-energized and the electrodes 1, 2 are separated again. This cycle repeats itself quickly and constantly and results a coherent rapid series of erosion sparks between the electrodes.

During the first few seconds of the process, a brown colloidal solution forms in the tub 5, which then changes into a dark, gray-black suspension in the further course of the process. When the suspension is subsequently left to stand, the particles change their color and become light gray. Analysis of these light gray particles reveals that they contain 88 weight percent zinc. If it is assumed that the color change is due to the formation of zinc hydroxide, then this analysis result corresponds to a particle composition of approximately 75 # zinc and 25 # zinc hydroxide. When examined, the particles were found to be irregularly shaped aggregates with a diameter of 5 to 5o / u. The individual components of these units have a diameter between 0.5 and 1 / y _#

109845/0469
BAD ORiQiNAL

The following examples show the effect caused by the addition A suspension of zinc-containing particles produced by the spark erosion process for filters made of paper and Cellulose acetate is achieved.

example 1

A suspension of light gray particles prepared in the manner described above was sprayed onto tobacco smoke filter paper of the type of the known "Myria- ^M paper until, after drying, an increase in weight of 0.5 # based on the weight of the paper was obtained.

Filter rods with the diameter of the cigarettes were formed from the paper treated in this way, and filter mouthpieces each 15 mm long cut.

Example 2

The process according to Example 1 was repeated, but applying enough suspension that the weight increase was finally 1% .

Example 3

The procedure according to Example 1 was repeated, but with the same amount of suspension plotted that ultimately the weight gain was 2.5 #.

Example 4

The process according to Example 1 was repeated with as much suspension plotted that the weight gain was ultimately 5 #.

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As

Example 5

The procedure of Example 1 was repeated and so much suspension plotted that the weight gain was Io, o #.

The filter mouthpieces produced according to the preceding examples were attached to cigarettes and, for comparison, smoked in a machine at the same time as cigarettes without pilter mouthpieces Performs one pull per minute with a duration of two seconds and a pull volume of 55 </ λ. The puff collected in each case was analyzed. The amounts retained by the filters treated according to the invention Hydrogen sulfide compounds and hydrogen cyanide are given in Table I below.

Table I.

example Pressure gradient
cm water column
(for a gas
current from io5o com /
min.) ¹ filter effect
filter
% * the 15 mm 1 5.8 sulfur
hydrogen
links Cyanide
material 2 4, o 42 25th 5 5.5 52 42 4th 5.8 75 5o 5 6.1 82 54 8o 6o

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Example 6

An endless strand of cellulose acetate fiber with a single gauge of 5 denier and a total gauge of 72,000 denier. was with a aqueous suspension of zinc-containing particles produced in commercial quantities by the electrical discharge machining process, sprayed. The proportion of the particles was 2o # of the total weight of the Suspension. The treated fiber strand was put on a common machine for the production of filter rods and processed into filter rods. These were then dried at about 21 ° C. for 48 hours andin an air conditioner at about 21 ° C and 6o # more relative Moisture conditioned.

After analyzing the filter rods contained 2.3 wt -.% Zinc.

Example 7

As described in Example 6, filter rods were produced, wherein however, so much pellets were applied that the zinc content of the Filter rods was 4.6 #.

Example 8

Filter rods were made as described in Example 6, but made to contain 5 * 1 # zinc.

_ ^ The filter rods manufactured according to Examples 6 to 8 and

co were cut into 15 mm long pieces, at oo

* - cigarettes arranged and smoked as described earlier. The each- • cn

* "■■ * Weil's collected smoke was analyzed, the quantities determined ο

^ of hydrogen sulfide compounds and hydrogen cyanide, which by

the filters treated according to the invention had been retained, are listed in Table II.

Table II

example Pressure gradient Filter effect 67 at 15 mm cm water column length 86 (with a gas flow 87 from Io5o ccm / min. Sulphurous water Cyan water fabric connection material gene 6th 5.4 61 7th 5.6 78 8th 5.9 79

The taste of the smoke was enhanced by the addition or treatment of the pilter material in none of Examples 1 to 8 adversely affected.

The invention also comprises the device or circuit described for producing a finely divided zinc containing Powder.

- Expectations -

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Claims (6)

Expectations 1, a method for treating a fibrous, thread-like or sheet-like filter material for tobacco smoke, characterized in that the filter material is treated with a finely divided, zinc-containing powder which is produced by a high-energy atomization process carried out under water. 2. The method according to claim 1, characterized in that the powder is produced by the erosion effect of electrical sparks between two electrodes immersed in water. J3. Process according to claim 1 or 2, characterized in that the filter material is treated with the zinc-containing powder in the form of an aqueous suspension and dried. 4. The method according to one or more of claims 1, 2 or 3 *, characterized in that the filter material is treated up to a weight increase of up to lo # based on its operating weight. 5. The method according to one or more of claims 1, 2 or J5, characterized in that the filter material is treated up to a weight increase of 2 to 5 $ based on its set weight. 6. Apparatus for the production of a finely divided, zinc-containing substance, in particular for the treatment of a fibrous, thread-like or sheet-like filter material for tobacco smoke, characterized by a spark erosion apparatus, the two zinc electrodes immersed in water, a device for periodic separation of the and Electrodes / has a capacitor, the capacitor such is arranged that it is alternately charged from a power source and discharged via the separate electrodes. 109845/0469 Empty Θ4 t