DE1532162A1 - Cigarette filters - Google Patents

Description

Oarl Freudenberg July 13, 1966 ι ir ο ο ι c ο

. ■ - 'loo / 104

Weinheim / Bergstrasse Off. 422 Br.z / Sn. -

Cigarette filters

It is already known to use a filter mouthpiece for cigarettes Mistake. The latter has the task of removing harmful combustion products from tobacco, in particular, from cigarette smoke Absorb droplets of tar and nicotine.

A wide variety of cigarette fil- teas are used in the cigarette industry known from fiber materials. Need to raise the filter effect these materials in the filter have a certain rigidity in order to achieve a good one for a given diameter of the cigarette filter Ensure handling.

To produce these known mouthpieces with a filter effect today 'almost exclusively crimped cellulose acetate fibers used, which were twisted together to form a parallel strand, which is sprayed with an organic plasticizer for solidification became. This cellulose acetate strand then becomes a funnel-like one Device supplied. After leaving the funnel tube, the strand is wrapped with cigarette paper and then in the the desired lengths a ·,

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Furthermore, even today in a small percentage " Paper filter processed. It is a special paper, which is creped in order to achieve as large a surface as possible, which is necessary for the degree of absorption of the filter is decisive. The main disadvantage of these paper filters is in the high moisture absorption of the paper cellulose, which causes an unfavorable swelling of the filters and the associated decrease in absorption.

Except for the disadvantages of those used today Filters also contain foreign substances such as plasticizers avoid all filters.

Such mouthpieces made of pure paper cellulose also have only a low level of rigidity. They are also sensitive to moisture. When you press the filter mouthpiece with your moist lips, the initially bulky fiber structure is destroyed. Of the The smoker then has to "pull" harder because the resistance that the filter offers to the passage of smoke has become greater. The need to "pull" harder on the cigarette j causes many smokers to prefer cigarettes without a mouthpiece.

It has also already been proposed to use cigarette filters made of "polyolefin threads, which in turn are twisted into a strand. Such filters are indeed stiffer and less Sensitive to moisture as those made of cellulose acetate fibers, but it is difficult to put the polyolefin fibers or threads in * to hold together such a strand. For cellulose acetate fibers

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is this easy. There all you need to do is add a plasticizer, set. This causes the cellulose acetate fibers or threads Somewhat sticky on its surface and thus the twisted one becomes cardboard Strand into a stable rod.

Polyolefin fibers, on the other hand, behave towards the usual Plasticizers inert. Nevertheless, the twisted together in a strand To glue fibers together in such a way that a stable rod is created, you can heat the twisted strand. The fibers naturally soften again on the surface and stick together to a stable and relatively stiff rod.

Unfortunately, however, the loft or smoke negligence is one of those welded filter rod too low. ,

In the other procedure (German Auslegeschrift 1 212 459) the parallel strand of polyolefin fibers added up to 30 # of a second thermoplastic which is sensitive to plasticizers and thus causes the strand to solidify into a filter element. The disadvantages of these filters are particularly in the spatial arrangement of the fibers, so that the smoke particles to be separated migrate through the filter in the longitudinal direction of the fibers can.

Although in this process the polyolefin fiber strand is not welded, but only - similar to the cellulose acetate fiber strands - glued, the air resistance is such Filters very high.

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All known cigarette filters have a more disruptive effect The following

Naturally, all threads in a strand lie in one direction. If you cut from such a strand - which is subsequently wrapped with cigarette paper - an approximately 1 cm long one Piece off and graft it onto a cigarette, then the strands of the filter are parallel to the direction of flow of the cigarette smoke when pulling. This is unfavorable because the solid and liquid particles in cigarette smoke move along the ducts can snake between these threads lying in the direction of the withdrawing smoke. Therefore, the degree of separation becomes great be low. If it were possible to arrange the threads in the filter, e.g. across the direction in which the smoke was drawn off, the degree of separation would be significantly higher with practically the same permeability.

However, it has not yet been possible on an industrial scale to manufacture such filters. In laboratory tests it has also been found that an arrangement in which all fibers are in the filter lie approximately across the direction of the smoke, also does not yet allow the maximum degree of separation with minimal air resistance.

This is only possible if, according to the invention, endless thermoplastic Arranges threads in the cigarette filter in an "ideal tangled position". With other ports: Endless threads are first placed on a base in such a way that there is no direction in the resulting fleece

seems preferred.

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This tangled fiber fleece, consisting of endless thermoplastic threads, is only then fed to the funnel-shaped device. A stable, stiff filter rod arises there, which with
Cigarette paper is wrapped.

The production of a fiber fleece in which thermoplastic threads are arranged in an ideal random position is known. It is only optional here to refer to French patents 1 402 829,
1 364 916 or the GDR patent specification 44 610 referenced.

In order to give the filter rod formed from these tangled nonwovens greater rigidity, it is advisable to also flute the nonwovens. In other words: The fleece is allowed to run through a pair of steel rollers at a temperature of 80 to 150 C, in which at least
a roller has an embossing, as can be seen for example from FIGS. 2 and 3 of the English patent specification 898,432. However, any other sexton is also suitable. It should only be noted that the roller has about five point-shaped elevations over a length of 1 cm. At . As they pass through the roller gap, the fibers in the fleece are also welded to one another at the raised points.

Such a point-like welding can also be achieved if you close the spun threads at the moment
a fleece in which they have not yet cooled down. When placed in a hot state, the threads are still soft on their surface and are partially pre-welded together.

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Of course, you can also use both methods of the "point-like - gen * Combine nonwoven reinforcement, i.e. the threads first put down while hot and then flute.

According to the invention, plasticizer-free polyolefins, in particular Polyethylene and polypropylene and polyamides are preferred. When working with plasticizer-free thermoplastics, it is avoided once that the threads baked together too much after being twisted into a strand, whereby the air permeability is strong is reduced. On the other hand, there is no risk of softening agents when smoking filters with softener-free filters is always much more volatile than the thermoplastic Thread material - with inhaled v; ird »

The diameter of the threads in the. Tangled fleece (and ultimately in the filters) can be varied as required. Mostly you choose a diameter between 5 and 50 / u.

The use of threads also proved to be particularly beneficial a star-shaped cross-section. A. Such a cross-section naturally results in a thread whose surface is larger than that Surface of a thread with a usual round cross-section.

The production of the threads with a star-shaped cross-section (below any non-round profile should be understood) is simple. It is only when spinning out the thermoplastic melts according to the procedures as they are, for example, in the French patent

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Writings 1 402 829, 1 364 916 or the GDR patent specification 44,610 ^ are described using nozzles with a corresponding star-shaped cross-section »The deposition of such" star threads into one Fleece and its further processing into a cigarette filter takes place as usual.

Of course, you can also spin different melts from the nozzles. In this way, a random fiber mixed fleece is created. The degree of separation of such fleeces is often higher than expected Cumulative effect. '

The degree of separation of the filters according to the invention can be increased if the threads are used with other adsorbents, such as e.g. powdered coal.

The cigarette filters according to the invention adsorb when used of polyolefin threads up to 100 ^ more tar and nicotine than one Cigarette of the same length, same diameter and same thickness. At the same time the air resistance is in the case of the filters according to the invention lower than with all known cigarette filters. You can may also be creped.

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Claims (6)

Patent claims 1. Cigarette filter, consisting of endless thermoplastic fibers ■ - ■ "■ ',' ■ ■ -. ■■. '■ ..-" ■ - ■ - - - ".- ■ - ■ - - * - ■ - . Den, characterized in that the endless thermoplastic · Threads are in the form of an ideal Y ^ irrfaserrlieses «■■■ -.- /" 2. cigarette filter according to claim 1, characterized in that the thermoplastic threads of the tangled fiber fleece at their points of contact are connected to each other in a punctiform manner » 5 «cigarette filter according to claim t and 2 _r characterized ^ that the threads have a star-shaped cross-section. : 4. cigarette filter according to claim 1 to 3, characterized in that that the thermoplastic threads made of ^ olyoliefinen, such as poly; ethylene and polypropylene consist of * 5V cigarette filter according to A ^ sp $ * ach 't to 4 »thereby that the fleeces consist of threads ^ different chernioplasts * 6. cigarette filter according to claim. 1 t> is; 5 »characterized by. \ that carbon particles are embedded on and in the threads *