WO2009083093A2 - Filter tow strip, filter rod machine, method for producing filter tow strips and method for producing filter rods - Google Patents

Abstract

The invention relates to a filter tow strip, especially twin tow from cross-linked and crimped filaments which form at least two partial strips (12a, 12b) that are interlinked by a section of reduced cross-linking density (11), the linking filaments (13) being interlooped and/or interlocked in such a manner that the linking filaments form intersections (14). The filter two strip is characterized in that the maximum cross-cutting force of the partial strips (12a, 12b) does not exceed 20 cN on a length of approximately 20 cm of the filter tow strip (10) and/or the number of the linking filaments (13) does not exceed 200 cross-locking and/or cross-looping filaments on a length of approximately 20 cm of the filter tow strip (10) when impinged with the maximum cross-cutting force.

Description

 Filter tow, filter rod machine. Method for producing filter tow strips and method for producing filter rods

The present invention relates to a filter tow strip having the features of the preamble of claim 1, a filter rod machine, a method for producing a filter tow strip and a method for producing filter rods.

A filter tow strip of the aforementioned type is known, for example, from EP 0 629 722 A1, which is based on the Applicant.

For the production of cigarettes filters are used, which are made of a band or a continuous strand of crimped cellulose acetate fibers, the so-called filter tow. In the production of filter tow, spun filaments of cellulose acetate are crimped in a stuffer box, whereby the impressed crimp structure is fixed while passing through a dryer. After the filter tow has been brought to a constant final moisture content, it is loosely placed in jugs several meters high in regular patterns. The loose tow layer is then compacted in bale presses into a filter tow bale and finally packed, which is provided for further processing into filters.

A detailed discussion of the manufacturing process of Filter Tow is disclosed in the article CA Filter Tow for Cigarette Filter, Paul Rustemeyer, Macromolecular Symposia 208 (2004), 267-291.

The processing of filter tow to filter rods is carried out on a filter rod machine on which the filter tow in a processing section as strong as possible to develop its maximum filling power, which is then gathered on the format of the future cigarette filter and coated with paper. To buckle the filter tow, it is pulled apart by means of compressed air driven spreader nozzles and stretched by a system of draw rolls with threaded or screwed surfaces. Thereafter, the spread filter tow is fed to a triacetin spray box, in which the acetate surface is dissolved and tackified. In the format part of the filter rod machine, the filter tow band is gathered and compressed to the cross section of the future filter rod. During this process, the filaments stick together and form a three-dimensional spatial network structure with the desired filter hardness for further processing and the consumer.

To increase productivity, it is known, for example from DE 43 20 317, which is also due to the applicant to produce filter rods on double filter rod machines, in which two filter tow strands are processed in parallel and synchronously. In order to achieve the same properties in the two strands, it is described in the aforementioned EP 0 629 722 A1 to use a multiple-width filter tow strip which has a predetermined tear line. The filter tow strip can be divided along the predetermined tear line into individual strips, each with the same total titre. Due to the defined divisibility of the total or double stripe in two strips, the double-width filter tow strip is also referred to as twin tow. In order to separate the multiple-width filter tow strip, it is disclosed in EP 0 629 722 A1 that the strip is subjected to a stretching force in the longitudinal direction which causes the strip to be separated into two or more parts.

For problem-free production and consistent quality of the filter rods, it is important that the division of the multiple-width filter tow strip is as even as possible and the partial strands run as evenly as possible into the double rod machine.

The invention has for its object to provide a filter tow strip, in particular twin tow of crosslinked and crimped filaments, which allows a problem-free processing on a filter rod machine, especially on a double filter rod machine, the separation of the filter tow strip for continuous production as evenly as possible should be done. The invention is further based on the object of specifying a filter rod machine, in particular a double filter rod machine, with which the filter tow strip can be separated without resistance, as well as a method for producing a filter tow strip, in particular a twin tow and a method for producing filter rods.

According to the invention, this object is achieved with regard to the filter tow strip by the subject-matter of claim 1, with regard to the filter rod machine by the subject-matter of claim 7 and with regard to the methods by the subject-matter of claim 13 and the subject-matter of claim 19. The invention has the advantage that the separation of the filter tow strip according to the invention is achieved largely without problems even in fast-running processes. Due to the uniform binding force of the Filter Tow halves along the Twin Tows, voltage fluctuations and thus quality fluctuations of the filter rods are effectively avoided. In contrast to EP 0 629 722 A1, which discloses only the longitudinal breaking strength of the filter tow strip, the filter tow strip according to the invention is defined by the maximum transverse cutting force, which does not exceed 20 cN, and over a length of about 20 cm. This has the advantage that the release properties of the strip can be set much more accurately than in the strip according to EP 0 629 722 A1, so that the separation behavior of the strip is improved.

The division of the filter tow strip into two individual filter tow strips in front of the spreader nozzle or in front of the spreader nozzles of the filter rod machine according to the invention makes it possible, without difficulty - depending on the existing filter tow material - between a twin tow bale, i. a bale with a filter tow according to the invention, and, if necessary, two bales with standard filter tow to change.

Preferred embodiments of the invention are specified in the subclaims.

The invention will be explained in more detail below with reference to exemplary embodiments with reference to the accompanying schematic drawings.

In this show

1 shows a schematic cross section through a filter tow strip according to an embodiment of the invention, which is clamped for measuring the cross-cutting force in jaws.

2a-2f are sectional views of filter tow strips according to various embodiments of the invention, in which the connection region between the partial strips is arranged differently; and 3a, b, c are schematic representations of a detail of a double filter rod machine according to embodiments of the invention in the region of the separating device.

An example of a filter tow strip 10 according to the invention is shown in FIG. 1, wherein the illustrated filter tow strip 10 is a double-width filter tow strip, i. is a so-called Twin Tow made of cross-linked and crimped filaments. The filter tow strip 10 comprises two partial strips 12a, 12b, which are connected by a region of lower mesh density 11. The filaments 13, which connect the two partial strips 12a, 12b in the region of lower crosslinking density 11, are mutually looped and / or hooked in such a way that the connecting filaments 13 form crossing points 14.

The invention is not limited to filter tow strip 10 with two partial strips, but generally includes multi-width filter tow strip with a plurality of partial strips, for example. Three or four partial strips, which are respectively connected to each other.

The filter tow strip 10 according to FIG. 1 is clamped between two clamping jaws A of a measuring device which have moved apart so far that the two partial strips 12a, 12b of the filter tow strip or the twin tow and the connecting region 11 located therebetween can be seen with low crosslinking density , Instead of the jaws A comb clamps can be used, in particular for measurement in superimposed partial strips.

The connection region 11 is designed such that the maximum transverse separation force required to separate the partial strips does not exceed 20 cN over a length of approximately 20 cm. The maximum transverse separation force corresponds to the force perpendicular to the longitudinal extent of the filter tow strip 10, which occurs in a continuous expansion, ie in a continuous moving apart of the jaws A, just before the cross-cutting force decreases again and the partial strips are completely separated. The maximum cross-cutting force may be lower than 20 cN, for example 15 cN, 10 cN, 7 cN, 5 cN, 4 cN, 3 cN, 2 cN or 1 cN. In this case, the maximum cross-cutting force in a range of 0.5cN to less than 2OcN, wherein the lower limit of 0.5 cN can be combined with the above upper limits. Other possible lower limits are IcN, 1.5 cN, 2cN, 2.5cN.

Alternatively or in addition to the maximum transverse separation force, the separation behavior of the filter tow strip 10 can be determined by the number of binding filaments 13 in the connection region 11 between the two partial strips 12a, 12b. The detection of the binding filaments 13 takes place at the maximum of the cross-cutting force, i. just before the complete separation of the two partial strips 12a, 12b, as shown in Fig. 1. In the separation of the two partial strips 12a, 12b or halves, the binding filaments 13 are partially torn off and / or unhooked, wherein for the determination of the separation behavior, the still crossed or connected filaments shortly before the complete separation, i. be detected in the cross-cutting force maximum.

To determine the number of binding filaments 13, the connected or crossing filaments of the respective partial strips 12a, 12b are each regarded as a filament. This means that the number of binding filaments 13 essentially corresponds to the number of crossing points 14. In the embodiment according to FIG. 1, the connection denoted by I at the right end of the clamping jaws A comprises two filaments 13 interleaved with one another, which are regarded as a filament for determining the number of binding filaments 13 and have a point of intersection 14. The same applies to compound II, in which two filaments 13 are entangled and form a point of intersection 14. In compound III, four filaments 13 are connected together and form two crossing points 14. The compound III therefore comprises two binding filaments 13. This means that when subjected to the maximum cross-cutting force at most 200 crossing points are provided to a length of 20 cm. The lower limit of the number of crossing points to a length of 20cm can be 1 crossing point. 2, 3, 4, 5, 6, 7, 8, 9, 10 crossing points are also possible as the lower limit.

Depending on the manufacturing process, the filaments 13 may either be only looped, ie the individual filaments 13 form stitches or loops that mutually engage and form a connection. The filaments 13 can also only be hooked, wherein at least one filament 13 of a connecting filament pair forms a free end and into a loop or into another filament hook intervenes. Furthermore, a combination of entangled and entangled filaments 13 is possible. The connecting filaments 13 form crossing points 14, ie the opposing filaments 13 of the two partial strips 12a, 12b meet and cross each other.

With regard to the maximum cross-cutting force, it is sufficient if 95% of the samples at which the maximum cross-cutting force of the Filter Tow strip is measured have an upper limit of 20 cN over a length of approx. 20 cm for the maximum cross-cutting force. That is, the invention also includes filter tow strips where in places the maximum cross-cutting force exceeds the upper limit of 20 cN, as long as this does not significantly affect the continuous operation of the filter rod machine processing the filter tow strip. The aforementioned tolerance of 95%, better still 99% has been found to be sufficient. It has also been found to be advantageous if the Twin Tow has a connection region which is such that 95% of the samples of a Twin Tows connect less than 50 transverse hooking filaments to 20 cm clamping length of the two Tow halves or partial strips. Further, 99% of the samples of a twin tow may have less than 100 cross-herniated filaments on a 20 cm chuck length of the substrips 12a, 12b.

It is understood that the reference length of 20 cm of the Filter Tow strip section for measuring the maximum cross-cutting force can be chosen differently, for example longer. The maximum cross-cutting force with a longer reference section increases accordingly.

In contrast to a filter tow strip, which is optimized with respect to a longitudinal expansion force, the filter tow strip according to the embodiment of the invention in the connection region, i. in the region of low or low crosslink density 11 with respect to the cross-cutting force optimized. As a result, an improved and secure separation of the partial strips 12a 12b is achieved, since the optimized parameter, namely the transverse separating force, is correlated with the separating direction which runs transversely to the longitudinal direction of the filter tow strip 10.

To measure the quality-relevant parameters of the Twin Tows, a force-extensometer with clamping devices is used, which is a pair of jaws having a clamping length of 20 cm. To measure the cross-cutting force, a 20 cm long filter tow is clamped in the longitudinal direction with the edges of the filter Tows in the jaw pair. The jaws A in the force-extensometer are slowly moved apart so that the Twin Tow is first stretched. The required force is measured. The crossing crimped filaments of the fiber strand form a nonwoven structure. In the connecting region between the partial strips, ie in the region with a low crosslink density, the dividing seam between the two twin tow halves opens. The open area is characterized by the number of cross-linked or cross-wound filaments which form a cross pattern, for example. The jaws are further moved apart, with the cross-cutting force passes through a maximum at the point at which the filaments that hold the two tow halves together are maximally stretched. The number of cross-linked filaments is then detected.

As the jaws widen further, the entanglements between the binding filaments of the two tow tow halves of the Twin Tows tear apart and the cross-cutting force decreases.

In the figures 2a - 2f different embodiments are shown, in which the partial strips 12a, 12b of the filter tow strip 10 are arranged differently. According to FIG. 2a, the partial strips 12a, 12b are arranged side by side, the connecting region 11 and the partial strips 12a, 12b being arranged in one plane. The arrangement according to FIG. 2a can be produced, for example, by jointly crimping the two partial strips 12a, 12b, wherein the crosslinking density in the connection region 11 is adjusted so as to give a maximum transverse separating force of 20 cN.

According to FIGS. 2b-2f, the two partial strips 12a, 12b are overlapping, ie arranged at least partially or completely overlapping. The connection of the two partial strips can be produced by mechanical needling or by needling by means of an air jet or a jet of water. In the exemplary embodiment according to FIG. 2b, the partial strips are arranged overlapping one another in the edge region. According to FIG. 2c, the partial strips 12a, 12b are arranged completely overlapping one above the other, with the connecting filaments 13 acting as a common central track. are formed. In the embodiment according to Rg. 2d, the connecting filaments 13 and the connecting portion 11 are formed as an edge track. It is also possible, as shown in Fig. 2e, to provide the connecting filaments 13 over the entire width of the overlapping partial strips 12a, 12b. Another way to connect the two partial strips 12a, 12b is to arrange the connecting filaments 13 in the longitudinal direction of the partial strips distributed arbitrarily, as shown in Fig. 2f.

In the figures 3a - 3c three embodiments are shown for double filter rod machines, each having two spreader nozzles 20a, 20b. The other machine parts that are usually present, for example, the stretching device, the spray device and the format part are not shown. As can be seen in FIG. 3 a, a separating device 21 in the form of a separating wedge 23 is arranged upstream of both spreader nozzles 20 a, 20 b, the separating device 21 being arranged between the two spreader nozzles 20 a, 20 b. In this case, the separating edge of the separating wedge 23 counter to the conveying direction of the filter tow strip 10, so that the filter tow strips 10 is divided by the separating edge. For better guidance of the separating wedge 23 two guide rings 22a, 22b downstream and a guide ring 24 upstream. In the exemplary embodiment according to FIG. 3 a, the guide rings 22 a, 22 b may be arranged such that they exert a normal force component on the partial strips 12 a, 12 b.

The two spreader nozzles 20a, 20b can also be used as separating device 21 in that the two spreader nozzles 20a, 20b are arranged so that their inlet openings are not in line, so that a normal force component is exerted on the partial strips 12a, 12b (FIG. 3b) ). In this embodiment, due to the obliquely arranged spreader nozzles 20a, 20b, the separation point of the filter tow strip 10 the spreader nozzles 20a, 20b upstream. In order to enhance the separating effect, the separating wedge 23 according to FIG. 3 a may be provided at or in the region of the separation point of the obliquely arranged spreader nozzles 20 a, 20 b according to FIG. 3 b, as shown in FIG. 3 c.

The separating device 21 may be directly downstream of a force measuring device for measuring the voltage of the separated partial strips 12a, 12b in situ (not shown). Furthermore, a regulating device can be provided which acts in such a way that the conveying speed of the individual partial strips 12a, 12b is controlled by the voltage in the partial strips 12a, 12b.

In the method for producing filter tow strips, the crosslinking density in the connection region between the two partial strips 12a, 12b is adjusted such that a maximum cross-separation force of the partial strips of 20 cN to a length of about 20 cm or this force is not exceeded. This can be achieved, for example, by arranging the partial strips side by side side by side and crimping them together, the crosslinking density being controlled by the spacing of the partial strips from one another during crimping. The crosslinking density can also be controlled by mechanical needling or by needling by means of an air jet or a water jet, if the partial strips 12a, 12b are arranged partially or completely overlapping each other.

The filter tow strip 10 can already be separated into partial strips 12a, 12b before the bale packaging, wherein the separated partial strips 12a, 12b are placed in different cans or in a divided can with several storage areas or in a single can. It is also possible to insert the undivided filter tow strip into a jug and pack it into a bale. In the latter case, the separation of the filter tow strip in the sub-strips 12a, 12b takes place in the production of the filter rods, wherein the maximum transverse separation force with which the filter tow strip 10 is divided, 20 cN to a length of 20 cm does not exceed. To separate the filter tow strip 10, a double filter rod machine is preferably used which has a separating device in front of the spreader nozzles, as shown in FIGS. 3 a, 3 b, 3 c.

In a filter tow (Twin Tow) produced according to the invention, a release force was measured at the predetermined tear line, ie in the range of the lower crosslinking density of 7-12 cN and in another example of 2.5-4 cN. These values relate to the lower and upper limits of the scatter of the measurement. In further examples, a maximum cross-cutting force of IcN - 10 cN, as well as of 0.5 cN - 5 cN was measured. At the maximum cross cutting force of IcN - 10 cN, the number of connecting filaments or the number of crossing points was 2 - 20. At the maximum cross cutting force of 0.5 cN - 5 cN, the number of connecting filaments or the number of crossing points was 1 - 10. The above values for the the number of connecting filaments is the median (at most half of the observations in a sample have a value <m and at most half a value> m).

Further examples gave the following values for the mean maximum cross-dividing force / median of the number of connecting filaments: 8cN / 80, 7cN / 25, 2cN / 4 and 4cN / 8.

The cross-cutting force and the number of connecting filaments can be adjusted, for example, as explained above, by varying the spacing of the partial strips in the crimping machine.

LIST OF REFERENCE NUMERALS

10 filter tow strips

11 area with lower crosslink density

12a, 12b partial strips

13 filaments

14 crossing points

20a, 20b spreader nozzle

21 separating device

22a, 22b guide rings

23 separating wedge

24 guide ring

A jaws

***

Claims

claims Filter tow strips (10), in particular twin tows of crosslinked and crimped filaments, which form at least two partial strips (12a, 12b) which are connected by a region of lower crosslinking density (11), wherein the connecting filaments (13) loop each other and / or are hooked such that they each form crossing points (14), characterized in that over a length of about 20 cm of the filter tow strip (10), the maximum transverse separation force of the partial strips (12a, 12b) does not exceed 20 cN and / or over a length of about 20 cm of the filter tow strip (10), the number of connecting filaments (13) does not exceed 200 crosshatching and / or transverse looping filaments upon application of the filter tow strip (10) with the maximum cross-cutting force. 2. Filter Tow strip (10) according to claim 1, characterized in that the maximum transverse separating force <15 cN, in particular <10 cN, in particular <7 cN, in particular <5 cN, in particular <4 cN, in particular <3 cN, in particular < 2 cN, in particular <1 cN. 3. Filter Tow strip (10) according to claim 1 or 2, characterized in that the number of cross-hooking and / or querverschlaufenden filaments (13) in the region of lower crosslink density (11) <150, in particular <125, in particular <100, in particular <75, in particular <50, in particular <40, in particular <30, in particular <25, in particular <20, in particular <15, in particular <10, in particular <5. 4. Filter Tow strip (10) according to at least one of claims 1 to 3, characterized in that the partial strips (12a, 12b) are arranged side by side. 5. Filter Tow strip (10) according to at least one of claims 1 to 3, characterized in that the partial strips (12a, 12b) in the edge region overlapping ü- are arranged one above the other. 6. Filter Tow strip (10) according to at least one of claims 1 to 3, characterized in that the partial strips (12a, 12b) are arranged one above the other and the connecting filaments (13) lie in the region of the overlapping of the partial strips (12a, 12b), in particular as a common central track, edge track, distributed over the entire width or distributed randomly in the longitudinal direction. 7. Filter rod machine, in particular double filter rod machine with at least one spreader nozzle (20a, 20b), a stretching device, a spraying device and a format part, characterized in that in front of the spreader nozzle (20a, 20b) at least one separating device for separating partial strips (12a, 12b) of the Filter tow strip (10), in particular of the Twin Tows, is arranged. 8. Machine according to claim 7, characterized in that the separating device (21) comprises at least two guide rings (22a, 22b), which are mounted so that they exert on the partial strips (12a, 12b) a normal force component. 9. Machine according to claim 7 or 8, characterized in that the separating device (21) comprises at least one in the conveying direction of the filter tow strip (10) arranged separating wedge (23). 10. Machine according to at least one of claims 7 to 9, characterized in that the separating device (21) comprises two spreader nozzles (20a, 20b) which are arranged so that they exert on the partial strips (12a, 12b) a normal force component, there their inlets do not line up. 11. Machine according to at least one of claims 7 to 9, characterized in that the separating device (21) is a force measuring device for voltage measurement of the separated partial strips (12a, 12b) in situ immediately downstream. 12. Machine according to at least one of claims 7 to 11, characterized in that a control device is provided which acts such that the conveying speed of the individual partial strips (12a, 12b) is controlled by the voltage in the partial strips (12a, 12b). 13. A method for producing filter tow strips (10), in particular according to one of claims 1 to 6, in which at least two partial strips (12a, 12b) of crosslinked and crimped filaments (13) are surrounded by a region of lesser cross-sectional tion density (11) are connected, wherein the filaments (13) in the region of lower crosslink density (11) are mutually entangled and / or hooked and crossing points (14) form such that the maximum transverse separation force of the partial strips 20 cN over a length of about 20 cm of the filter tow strip (10) and / or the number of connecting filaments 200 transverse and / or querverschlaufende filaments (13) over a length of about 20 cm of the filter tow strip (10) upon exposure of the filter tow strip ( 10) with the maximum cross-cutting force does not exceed. 14. The method according to claim 13, in particular for producing a filter tow strip according to claim 4, characterized in that the partial strips (12a, 12b) are arranged side by side and crimped together. 15. The method according to claim 13, in particular for producing a filter tow strip according to claim 5, characterized in that the partial strips (12a, 12b) partially overlapping one another and mechanically treated by needling or with an air jet or a water jet so that binding Filaments arise. 16. The method according to claim 13, in particular for producing a filter tow strip according to claim 6, wherein the partial strips (12a, 12b) completely overlapping led and treated mechanically by needling or with an air jet or a water jet so that binding filaments (13 ) arise. 17. The method according to at least one of claims 13 to 16, characterized in that the filter tow strips in the sub-strips (12a, 12b) separated and the separated sub-strips (12a, 12b) in different jugs or in a divided jug with several storage areas or be placed in a single pot. 18. The method according to at least one of claims 13 to 16, characterized in that the undivided filter tow strip (10) is inserted into a jug. 19. Method for Making Filter Rods from Filter Tow Strips of crosslinked and crimped filaments, wherein a filter tow strip (10), in particular Twin Tow, is conveyed through a processing part and a format part, wherein the filter tow strip (10) at least two interconnected by a region of lower crosslink density (11) partial strips (12a, 12b) and the filaments (13) in the region of lower crosslink density (11) are mutually interlaced and / or hooked such that the filaments (13) form crossing points (14) separating the sub-strips (12a, 12b) in front of the format part with a maximum transverse separating force equal to 20 cN over a length of the filter Tow strip of about 20 cm does not exceed. * * *