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EP0996778A1 - Cellulose acetate with trilobal cross section - Google Patents

Cellulose acetate with trilobal cross section

Info

Publication number
EP0996778A1
EP0996778A1 EP98943731A EP98943731A EP0996778A1 EP 0996778 A1 EP0996778 A1 EP 0996778A1 EP 98943731 A EP98943731 A EP 98943731A EP 98943731 A EP98943731 A EP 98943731A EP 0996778 A1 EP0996778 A1 EP 0996778A1
Authority
EP
European Patent Office
Prior art keywords
cellulose acetate
filaments
cross
form factor
section
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP98943731A
Other languages
German (de)
French (fr)
Other versions
EP0996778B1 (en
Inventor
Wolfgang Koppe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cerdia Produktions GmbH
Original Assignee
Rhodia Acetow GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rhodia Acetow GmbH filed Critical Rhodia Acetow GmbH
Publication of EP0996778A1 publication Critical patent/EP0996778A1/en
Application granted granted Critical
Publication of EP0996778B1 publication Critical patent/EP0996778B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
    • A24D3/00—Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
    • A24D3/06—Use of materials for tobacco smoke filters
    • A24D3/08—Use of materials for tobacco smoke filters of organic materials as carrier or major constituent
    • A24D3/10—Use of materials for tobacco smoke filters of organic materials as carrier or major constituent of cellulose or cellulose derivatives
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/253—Formation of filaments, threads, or the like with a non-circular cross section; Spinnerette packs therefor
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
    • D01F2/24—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives
    • D01F2/28—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives from organic cellulose esters or ethers, e.g. cellulose acetate
    • D01F2/30—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives from organic cellulose esters or ethers, e.g. cellulose acetate by the dry spinning process
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2933—Coated or with bond, impregnation or core
    • Y10T428/2964—Artificial fiber or filament
    • Y10T428/2965—Cellulosic
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2973—Particular cross section

Definitions

  • the invention relates to cellulose acetate filaments with a trilobal cross-sectional shape and a degree of substitution of about 2.1 to 3.0.
  • Cellulose acetate filaments used in the manufacture of filter tow should have as large a specific surface area as possible, i.e. have the largest possible surface area per unit mass of filter tow in order to offer a large active surface area for the pollutants in the cigarette smoke. This enables a high filtration capacity with economical use of raw materials.
  • Important parameters for the determination of the specific surface are the filament titer, which gives the mass of the filament per length, as well as the form factors PE and KH, each of which is a measure of the ratio of the cross-sectional area to the square of the circumference or to the area of the convex sheath . To form a large specific surface, these parameters must be kept as low as possible.
  • Trilobal cross-sections represent a cross-sectional shape that is favorable for obtaining low form factors and thus a high specific surface. Filaments of trilobal cross-sectional shape are known in the prior art and are spun from nozzles that have a triangular cross-sectional area. Such a manufacturing method is disclosed for example in DE 43 02 055.
  • the trilobal, ie three-armed, star-shaped formation of the cellulose acetate filaments arises in this process by evaporation of the solvent, generally acetone, after spinning.
  • the values for the form factors which can be achieved with these nozzles according to the prior art are approximately 0.360 to 0.400 for the form factor PE and 0.580 to 0.620 for the form factor KH.
  • Fibrillated cellulose ester fibers with a small average diameter and a large specific surface are known from EP 0 711 512. However, there is no reference in this document to a trilobal cross-sectional shape of these fibers. Rather, their morphology is almost undefined, i.e. branched to a high degree of order.
  • a cellulose ester solution after extrusion from a nozzle is passed into a precipitation medium for the cellulose ester, with shear forces acting on the extrudate. Only the fibers fibrillated in this way have a high specific surface.
  • the geometric fiber cross-section has for the creation of this specific
  • the fiber length of the cellulose esters known from this publication is generally about 0.1 to 10 mm and preferably about 0.2 to 5 mm. As a result, no continuous filaments are produced.
  • the BET Method applied, the principle of which is based on the fact that the surface of a solid adsorbs gas molecules in a certain amount. With this method, the additional surface created by the finest branches of the fibrillation can be measured exactly.
  • the object described above is achieved by cellulose acetate filaments with a degree of substitution of approximately 2.1 to 3.0 and a trilobal cross-sectional shape which have a filament titer of less than 3.3 dtex, a form factor PE of less than 0.320 and a form factor KH of have less than 0.560.
  • the form factor PE is less than 0.320 in the context of the invention.
  • a minimum value of approximately 0.18 is assumed, the range from approximately 0.2 to 0.3 being preferred.
  • the preferred lower value can be about 0.35, the range from about 0.4 to 0.52 being particularly preferred.
  • the filaments described are obtained by spinning from nozzles with a trilobal cross-sectional shape.
  • the cross-sectional area of the nozzles according to the invention is approximately
  • the ratio of the surface to the mass of the filaments can be considerably improved.
  • Filaments with a titer of 3 dtex and a form factor PE of 0.380 have a specific surface area of 0.290 m 2 / g. If the form factor PE is reduced to 0.300, a specific surface area of 0.327 m 2 / g is obtained for filaments of the same fineness.
  • the spinning process can be carried out in a conventional manner using the dry spinning process.
  • the cellulose acetate filaments according to the invention are distinguished both by a high smoke absorption capacity and by an easy manufacture. Since the degree of substitution DS of the cellulose acetate is about 2.1 to 3.0, in particular about 2.3 to 2.9 and particularly preferably 2.3 to 2.7, it is possible to work with a conventional spinning solution with about 3% water content. A DS of about 2.5 is considered to be particularly preferred. —O c -
  • the spinning process carried out with the specified parameters gives filaments with a titer of 3.0 dtex per filament, a form factor PE of 0.290 and a form factor KH of 0.505 and thus advantageously a large specific surface. They thus show improved filtration properties for smoke ingredients in cigarettes.
  • Viscosity of the spinning solution 71 Pa-s - o, -

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Textile Engineering (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Cigarettes, Filters, And Manufacturing Of Filters (AREA)
  • Artificial Filaments (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)

Abstract

The invention relates to cellulose acetate filaments with trilobal cross section and with a degree of substitution of approximately 2.1 to 3.0. They have a filament titer of less than 3.3 dtex, a PE form factor of less than 0.320, and a PH form factor of less than 0.560. These cellulose acetate filaments have particularly advantageous absorptive qualities when used in cigarette filters.

Description

Celluloseacetatfilamente mit trilobalem Querschnitt Trilobal cross-section cellulose acetate filaments
Die Erfindung betrifft Celluloseacetatfilamente mit trilobaler Querschnittsform und einem Substitutionsgrad von etwa 2,1 bis 3,0.The invention relates to cellulose acetate filaments with a trilobal cross-sectional shape and a degree of substitution of about 2.1 to 3.0.
Celluloseacetatfilamente, die für die Herstellung von Filter-Tow verwendet werden, sollten eine möglichst große spezifische Oberfläche, d.h. eine möglichst große Oberfläche pro Masseneinheit an Filter-Tow aufweisen, um eine große aktive Oberfläche für die im Zigarettenrauch befindlichen Schadstoffe zu bieten. Hierdurch wird ein hohes Filtrationsvermögen bei gleichzeitigem sparsamen Rohstoffeinsatz ermöglicht. Wichtige Parameter für die Bestimmung der spezifischen Oberfläche sind der Filamenttiter, der die Masse des Filaments pro Länge angibt, sowie die Formfaktoren PE bzw. KH, die jeweils ein Maß für das Verhältnis der Querschnittsfläche zum Quadrat des Umfangs bzw. zur Fläche der konvexen Hülle darstellen. Zur Ausbildung einer großen spezifischen Oberfläche müssen diese Parameter möglichst gering gehalten werden.Cellulose acetate filaments used in the manufacture of filter tow should have as large a specific surface area as possible, i.e. have the largest possible surface area per unit mass of filter tow in order to offer a large active surface area for the pollutants in the cigarette smoke. This enables a high filtration capacity with economical use of raw materials. Important parameters for the determination of the specific surface are the filament titer, which gives the mass of the filament per length, as well as the form factors PE and KH, each of which is a measure of the ratio of the cross-sectional area to the square of the circumference or to the area of the convex sheath . To form a large specific surface, these parameters must be kept as low as possible.
Eine zur Erlangung niedriger Formfaktoren und damit einer hohen spezifischen Oberfläche günstige Querschnittsform stellen die trilobalen Querschnitte dar. Filamente trilobaler Querschnittsform sind nach dem Stand der Technik bekannt und werden aus Düsen gesponnen, die eine dreieckige Querschnittsfläche aufweisen. Ein derartiges Herstellungsverfahren ist beispielsweise in der DE 43 02 055 offenbart. Die trilobale, d.h. dreiarmig- sternförmige Ausbildung der Celluloseacetatfilamente entsteht bei diesem Verfahren durch Verdampfen des Lösungsmittels, im allgemeinen Aceton, nach dem Ausspinnen. Die mit diesen Düsen gemäß dem Stand der Technik erzielbaren Werte für die Formfaktoren betragen etwa 0,360 bis 0,400 für den Formfaktor PE bzw. 0,580 bis 0,620 für den Formfaktor KH. Alternativ dazu ist es möglich, die gewünschte große Oberfläche durch ein Bündel extrem feiner Filamente kreisförmigen Querschnitts zu erhalten. Diese dünnen Filamente werden aus kleinen Rundlochdüsen ausgesponnen. Ein entsprechendes Verfahren geht aus der US-5 269 996 hervor. Allerdings gestaltet sich der Prozeß des Ausspinnens aus diesen sehr feinen Rundlochdüsen, die einen Durchmesser von weniger als 36 μm aufweisen, als äußerst schwierig. Bei der technischen Realisierung dieses Verfahrens treten somit erhebliche Probleme auf.Trilobal cross-sections represent a cross-sectional shape that is favorable for obtaining low form factors and thus a high specific surface. Filaments of trilobal cross-sectional shape are known in the prior art and are spun from nozzles that have a triangular cross-sectional area. Such a manufacturing method is disclosed for example in DE 43 02 055. The trilobal, ie three-armed, star-shaped formation of the cellulose acetate filaments arises in this process by evaporation of the solvent, generally acetone, after spinning. The values for the form factors which can be achieved with these nozzles according to the prior art are approximately 0.360 to 0.400 for the form factor PE and 0.580 to 0.620 for the form factor KH. Alternatively, it is possible to obtain the desired large surface area through a bundle of extremely fine filaments of circular cross-section. These thin filaments are spun out of small round hole nozzles. A corresponding method can be found in US Pat. No. 5,269,996. However, the process of spinning out these very fine round-hole nozzles, which have a diameter of less than 36 μm, is extremely difficult. Considerable problems arise in the technical implementation of this method.
Ein weiteres Verfahren zur Herstellung von Celluloseacetatfasern für die Zigarettenin- dustrie ist aus der US-A-5 512 230 bekannt. In dem darin beschriebenen Verfahren wird es durch Zufügen von 5 bis 40 % Wasser zur Spinnlösung ermöglicht, Celluloseacetatfasern mit einem Substitutionsgrad von 1,0 bis 2,2 auszuspinnen.A further process for the production of cellulose acetate fibers for the cigarette industry is known from US Pat. No. 5,512,230. In the process described therein, by adding 5 to 40% water to the spinning solution, it is possible to spin out cellulose acetate fibers with a degree of substitution of 1.0 to 2.2.
Es hat sich nun gezeigt, daß die vorstehend dargestellten Filamenttiter im Hinblick auf die wünschenswerten Eigenschaften in Filtermaterialien, insbesondere in Filtern von Zigaretten, insbesondere im Hinblick auf die Filtration von Rauchinhaltsstoffen, verbesserungsbedürftig sind. Vorschläge, diese Verbesserungen auf chemischem Wege zu erreichen, sind bekannt. Wesentliche Hinweise, den vorstehend geschilderten Stand der Technik besonders vorteilhaft weiterzubilden, indem physikalische Modifikationen vor- genommen werden, finden sich in der Literatur nicht.It has now been shown that the filament titers described above are in need of improvement with regard to the desirable properties in filter materials, in particular in filters of cigarettes, in particular with regard to the filtration of smoke constituents. Proposals to achieve these improvements chemically are known. The literature does not contain any essential information to further develop the state of the art described above in a particularly advantageous manner by making physical modifications.
Zwar sind aus der EP 0 711 512 fibrillierte Celluloseesterfasern mit einem geringen durchschnittlichen Durchmesser sowie einer großen spezifischen Oberfläche bekannt. Jedoch findet sich in dieser Druckschrift kein Hinweis auf eine trilobale Querschnittsform dieser Fasern. Vielmehr ist deren Morphologie nahezu von Undefinierter Form, d.h. bis zu einem hohen Ordnungsgrad verzweigt. Für die Herstellung derartiger fibrillierter, d.h. gespleißter, Fasern wird eine Celluloseesterlösung nach dem Extrudieren aus einer Düse in ein Ausfällungsmedium für den Celluloseester geleitet, wobei Scherkräfte auf das Ex- trudat einwirken. Nur die so fibrillierten Fasern weisen eine hohe spezifische Oberfläche auf. Der geometrische Faserquerschnitt hat für das Zustandekommen dieser spezifischenFibrillated cellulose ester fibers with a small average diameter and a large specific surface are known from EP 0 711 512. However, there is no reference in this document to a trilobal cross-sectional shape of these fibers. Rather, their morphology is almost undefined, i.e. branched to a high degree of order. For the manufacture of such fibrillated, i.e. of spliced fibers, a cellulose ester solution after extrusion from a nozzle is passed into a precipitation medium for the cellulose ester, with shear forces acting on the extrudate. Only the fibers fibrillated in this way have a high specific surface. The geometric fiber cross-section has for the creation of this specific
Oberfläche nur eine geringfügige Bedeutung. Die Faserlänge der aus dieser Druckschrift bekannten Celluloseester beträgt im allgemeinen etwa 0,1 bis 10 mm und vorzugsweise etwa 0,2 bis 5 mm. Es werden demzufolge keine Endlosfilamente hergestellt. Als Verfahren zur Messung der spezifischen Oberflächen dieser fibrillierten Fasern wurde die BET- Methode angewandt, deren Prinzip darauf beruht, daß die Oberfläche eines Feststoffes Gasmoleküle in bestimmter Menge adsorbiert. Mit dieser Methode kann somit die durch die feinsten Verästelungen der Fibrillierung zusätzlich entstandene Oberfläche exakt gemessen werden.Surface of minor importance. The fiber length of the cellulose esters known from this publication is generally about 0.1 to 10 mm and preferably about 0.2 to 5 mm. As a result, no continuous filaments are produced. As a method for measuring the specific surfaces of these fibrillated fibers, the BET Method applied, the principle of which is based on the fact that the surface of a solid adsorbs gas molecules in a certain amount. With this method, the additional surface created by the finest branches of the fibrillation can be measured exactly.
Es war demzufolge Aufgabe der Erfindung, Celluloseacetatfilamente mit trilobalem Querschnitt vorzuschlagen, die den oben geschilderten Stand der Technik im Hinblick auf die Effizienz bei der Absorption von Rauchinhaltsstoffen in Filtern von Zigaretten verbessern. Die Herstellung dieser Fasern soll einfach und mit konventionellen Techniken erfolgen können.It was therefore an object of the invention to propose cellulose acetate filaments with a trilobal cross section which improve the prior art described above with regard to the efficiency in the absorption of smoke constituents in filters of cigarettes. These fibers should be easy to produce and use conventional techniques.
Erfindungsgemäß wird die vorstehend beschriebene Aufgabe durch Celluloseacetatfilamente mit einem Substitutionsgrad von etwa 2,1 bis 3,0 und trilobaler Querschnittsform gelöst, die einen Filamenttiter von weniger als 3,3 dtex, einen Formfaktor PE von weni- ger als 0,320 sowie einen Formfaktor KH von weniger als 0,560 aufweisen.According to the invention, the object described above is achieved by cellulose acetate filaments with a degree of substitution of approximately 2.1 to 3.0 and a trilobal cross-sectional shape which have a filament titer of less than 3.3 dtex, a form factor PE of less than 0.320 and a form factor KH of have less than 0.560.
Es ist ersichtlich, daß ein Unterschreiten dieses Wertes von 3,3 dtex zusammen mit den günstigen Formfaktoren zu besonderen Vorteilen führt, nämlich zu einem verbesserten Absorptions- und Adsorptionsverhalten bei Einsatz in den Filtern von Zigaretten. Mit anderen Worten bedeutet das, daß bei gleichbleibender Masse an Filamenten eine vergrößerte Oberfläche erreicht wird. Diese Vergrößerung der spezifischen Oberfläche wird anders als bei der in der EP 0 711 512 beschriebenen Celluloseesterfaser durch eine Optimierung des geometrischen Querschnittes von Celluloseacetatfilamenten verwirklicht. Die erfindungsgemäßen Filamente sind nicht fibrilliert bzw. gespleißt. Ein unterer Grenz- wert für den Titer läßt sich nicht präzise angeben, wobei man jedoch unter praktischenIt can be seen that falling below this value of 3.3 dtex together with the favorable form factors leads to particular advantages, namely to improved absorption and adsorption behavior when used in the filters of cigarettes. In other words, this means that an increased surface area is achieved with the same mass of filaments. In contrast to the cellulose ester fiber described in EP 0 711 512, this increase in the specific surface area is achieved by optimizing the geometric cross section of cellulose acetate filaments. The filaments according to the invention are not fibrillated or spliced. A lower limit for the titer can not be specified precisely, but one under practical
Gesichtspunkten im Hinblick auf die Herstellung davon ausgehen kann, daß das Unterschreiten von etwa 0,7 dtex auf fertigungstechnische Schwierigkeiten stößt. Hierbei ist auf den Unterschied abzustellen, daß mit Düsen mit Rundlöchern auch niedrigste Filamenttiter erreichbar sind, was nicht gleichermaßen für die Filamente mit trilobalem Quer- schnitt, im Rahmen der vorliegenden Erfindung gefordert, gilt. Ein Bereich von etwa 0,7 bis 2,7 dtex, insbesondere etwa 1,0 bis 2,5 dtex, ist als besonders bevorzugt anzusehen.With regard to the production, it can be assumed that falling below about 0.7 dtex will encounter manufacturing difficulties. The difference here is that even the lowest filament titers can be achieved with nozzles with round holes, which does not apply equally to the filaments with a trilobal cross-section, as required in the context of the present invention. A range of approximately 0.7 to 2.7 dtex, in particular approximately 1.0 to 2.5 dtex, is to be regarded as particularly preferred.
Der Formfaktor PE beträgt im Rahmen der Erfindung weniger als 0,320. Hier könnte für den unteren Wert, ebenfalls im Hinblick auf praktische Erwägungen bei der Herstellung, von einem Mindestwert von etwa 0, 18 ausgegangen werden, wobei der Bereich von etwa 0,2 bis 0,3 bevorzugt ist.The form factor PE is less than 0.320 in the context of the invention. Here, for the lower value, also with regard to practical considerations during production, a minimum value of approximately 0.18 is assumed, the range from approximately 0.2 to 0.3 being preferred.
Ähnliche Erwägungen wie beim Formfaktor PE gelten auch für den Formfaktor KH im Hinblick auf die bevorzugten Rahmenbedingungen. Dabei kann man als bevorzugten unteren Wert etwa 0,35 angeben, wobei der Bereich von etwa 0,4 bis 0,52 als besonders bevorzugt angesehen werden kann.Similar considerations as for the form factor PE also apply to the form factor KH with regard to the preferred general conditions. The preferred lower value can be about 0.35, the range from about 0.4 to 0.52 being particularly preferred.
Die beschriebenen Filamente werden durch Ausspinnen aus Düsen mit trilobaler Quer- schnittsform erhalten. Die Querschnittsfläche der erfindungsgemäßen Düsen beträgt etwaThe filaments described are obtained by spinning from nozzles with a trilobal cross-sectional shape. The cross-sectional area of the nozzles according to the invention is approximately
0,002 mm2 bei einem Formfaktor PE des Kapillarquerschnitts der Düse von etwa 0,37. Die trilobale Querschnittsform der Celluloseacetatfilamente wird somit bereits durch den Querschnitt der Düsen vorgegeben. Dadurch sind Filamente mit im Vergleich zum Stand der Technik wesentlich günstigeren Formfaktoren erreichbar.0.002 mm 2 with a shape factor PE of the capillary cross section of the nozzle of approximately 0.37. The trilobal cross-sectional shape of the cellulose acetate filaments is thus already predetermined by the cross-section of the nozzles. As a result, filaments can be obtained with form factors that are significantly cheaper than in the prior art.
Durch die erfindungsgemäße Verringerung des Formfaktors kann das Verhältnis der Oberfläche zur Masse der Filamente erheblich verbessert werden. So weisen Filamente mit einem Titer von 3 dtex und einem Formfaktor PE von 0,380 eine spezifische Oberfläche von 0,290 m2/g auf. Bei einer Verringerung des Formfaktors PE auf 0,300 erhält man für Filamente desselben Feinheitsgrades eine spezifische Oberfläche von 0,327 m2/g.By reducing the form factor according to the invention, the ratio of the surface to the mass of the filaments can be considerably improved. Filaments with a titer of 3 dtex and a form factor PE of 0.380 have a specific surface area of 0.290 m 2 / g. If the form factor PE is reduced to 0.300, a specific surface area of 0.327 m 2 / g is obtained for filaments of the same fineness.
Dies entspricht einer Vergrößerung der Oberfläche von 13 % bei gleicher Masse der Filamente. Es ist anzumerken, daß obige Werte für die spezifischen Oberflächen allein durch geometrische Berechnungen ermittelt wurden und somit auf jeden Fall unterhalb derjenigen Werte liegen, die sich durch Messung gemäß der BET-Methode ergeben wür- den. Somit können die erfindungsgemäßen Filamente bei sparsamem Einsatz von Rohstoffen und damit auch mit verringertem Kostenaufwand realisiert werden.This corresponds to an increase in the surface of 13% with the same mass of the filaments. It should be noted that the above values for the specific surfaces were determined solely by geometric calculations and are therefore in any case below the values that would result from measurement according to the BET method. The filaments according to the invention can thus be produced with the economical use of raw materials and thus also at reduced cost.
Der Vorgang des Ausspinnens kann auf herkömmliche Art im Trockenspinnverfahren erfolgen. Somit zeichnen sich die erfindungsgemäßen Celluloseacetatfilamente sowohl durch ein hohes Rauchabsorptionsvermögen als auch durch eine leichte Herstellbarkeit aus. Da der Substitutionsgrad DS des Celluloseacetats etwa 2,1 bis 3,0, insbesondere etwa 2,3 bis 2,9 und besonders bevorzugt 2,3 bis 2,7, beträgt, kann mit einer üblichen Spinnlösung mit etwa 3 % Wassergehalt gearbeitet werden. Ein DS von etwa 2,5 gilt als ganz besonders bevorzugt. —o c—The spinning process can be carried out in a conventional manner using the dry spinning process. Thus, the cellulose acetate filaments according to the invention are distinguished both by a high smoke absorption capacity and by an easy manufacture. Since the degree of substitution DS of the cellulose acetate is about 2.1 to 3.0, in particular about 2.3 to 2.9 and particularly preferably 2.3 to 2.7, it is possible to work with a conventional spinning solution with about 3% water content. A DS of about 2.5 is considered to be particularly preferred. —O c -
Die Erfindung soll nun anhand von Beispielen erläutert werden. Bei den beschriebenen Beispielen wurde jeweils mit einer Celluloseacetat-Spinnlösung in Aceton gearbeitet.The invention will now be explained using examples. In the examples described, a cellulose acetate spinning solution in acetone was used in each case.
Beispiel 1:Example 1:
Spinnlösung:Spinning solution:
Substitutionsgrad des Celluloseacetats (DS): 2,48Degree of substitution of cellulose acetate (DS): 2.48
Konzentration des Celluloseacetats : 27,8 %Concentration of cellulose acetate: 27.8%
Wasserkonzentration : 3,5 %Water concentration: 3.5%
Viskosität der Spinnlösung: 68 Pa-sViscosity of the spinning solution: 68 Pa-s
Spinnbedinεungen:Spinning conditions:
Temperatur des Spinnkopfes: 56 °CTemperature of the spinning head: 56 ° C
Temperatur in der Spinnzelle: 65°CTemperature in the spinning cell: 65 ° C
Trilobale Düse mit 125 BohrungenTrilobal nozzle with 125 holes
Spinngeschwindigkeit : 300 m/min.Spinning speed: 300 m / min.
Verstreckungsfaktor: 1,6Draw factor: 1.6
Durch das mit den angegebenen Parametern ausgeführte Spinnverfahren werden Filamen- te mit einem Titer von 3,0 dtex pro Filament, einem Formfaktor PE von 0,290 sowie einem Formfaktor KH von 0,505 und damit vorteilhaft großer spezifischer Oberfläche erhalten. Damit zeigen sie verbesserte Filtrationseigenschaften für Rauchinhaltsstoffe von Zigaretten.The spinning process carried out with the specified parameters gives filaments with a titer of 3.0 dtex per filament, a form factor PE of 0.290 and a form factor KH of 0.505 and thus advantageously a large specific surface. They thus show improved filtration properties for smoke ingredients in cigarettes.
Beispiel 2:Example 2:
Spinnlösung:Spinning solution:
Substitutionsgrad des Celluloseacetats: 2,45Degree of substitution of the cellulose acetate: 2.45
Konzentration des Celluloseacetats: 28,5 % Wasser-Konzentration: 2,7 %Concentration of cellulose acetate: 28.5% water concentration: 2.7%
Viskosität der Spinnlösung: 71 Pa-s — o ,— Viscosity of the spinning solution: 71 Pa-s - o, -
Spinnbedingungen:Spinning conditions:
Spinntemperatur: 56°CSpinning temperature: 56 ° C
Temperatur in der Spinnzelle: 65°C Trilobale Düse Düsenquerschnittsfläche: 0,00118 mm2 Temperature in the spinning cell: 65 ° C Trilobal nozzle Cross-sectional area: 0.00118 mm 2
Spinngeschwindigkeit: 400 m/min.Spinning speed: 400 m / min.
Verstreckungsfaktor: 2,1Draw factor: 2.1
Mit den angegebenen Parametern werden Celluloseacetatfilamente mit einem Feinheits- grad von 2,1 dtex, einem Formfaktor PE von 0,303 sowie einem Formfaktor KH von 0,517 erreicht. Hier gelten dieselben Vorteile wie im ersten Beispiel.With the specified parameters, cellulose acetate filaments with a fineness of 2.1 dtex, a form factor PE of 0.303 and a form factor KH of 0.517 are achieved. The same advantages apply here as in the first example.
* * * * * *

Claims

Patentansprüche claims
1. Celluloseacetatfilamente mit trilobalem Querschnitt und einem Substitutionsgrad von etwa 2,1 bis 3,0, dadurch gekennzeichnet, daß sie einen Filamenttiter von weniger als 3,3 dtex, einen Formfaktor PE von weniger als 0,320 sowie einen Formfaktor KH von weniger als 0,560 aufweisen, wobei die Formfaktoren durch folgende Verhältnisse definiert sind:1. Cellulose acetate filaments with a trilobal cross section and a degree of substitution of about 2.1 to 3.0, characterized in that they have a filament titer of less than 3.3 dtex, a form factor PE of less than 0.320 and a form factor KH of less than 0.560 , where the form factors are defined by the following relationships:
PE = A*4π P2 und KH = A/A*, worin bedeuten: A = Querschnittsfläche des Filaments, P = Umfang des Filamentquer- schnitts und Ak = Fläche der konvexen Hülle des Filamentquerschnitts.PE = A * 4π P 2 and KH = A / A *, where: A = cross-sectional area of the filament, P = circumference of the filament cross-section and Ak = area of the convex sheath of the filament cross-section.
2. Celluloseacetatfilamente nach Anspruch 1, dadurch gekennzeichnet, daß sie einen Substitutionsgrad von etwa 2,2 bis 2,7 und insbesondere von etwa 2,5 aufweisen.2. Cellulose acetate filaments according to claim 1, characterized in that they have a degree of substitution of about 2.2 to 2.7 and in particular of about 2.5.
3. Celluloseacetatfilamente nach mindestens einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß sie einen Filamenttiter von etwa 0,7 bis 2,7 dtex und insbesondere von etwa 1,0 bis 2,5 dtex aufweisen.3. Cellulose acetate filaments according to at least one of the preceding claims, characterized in that they have a filament titer of about 0.7 to 2.7 dtex and in particular of about 1.0 to 2.5 dtex.
4. Celluloseacetatfilamente nach mindestens einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß sie einen Formfaktor PE von etwa 0,2 bis 0,3 aufweisen.4. Cellulose acetate filaments according to at least one of the preceding claims, characterized in that they have a form factor PE of about 0.2 to 0.3.
5. Celluloseacetatfilamente nach mindestens einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß sie einen Formfaktor KH von etwa 0,4 bis 0,52 aufweisen.5. Cellulose acetate filaments according to at least one of the preceding claims, characterized in that they have a form factor KH of about 0.4 to 0.52.
* * * * * *
EP98943731A 1997-07-16 1998-07-15 Cellulose acetate with trilobal cross section Expired - Lifetime EP0996778B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19730485A DE19730485C2 (en) 1997-07-16 1997-07-16 Trilobal cross-section cellulose acetate filaments
DE19730485 1997-07-16
PCT/EP1998/004409 WO1999004071A1 (en) 1997-07-16 1998-07-15 Cellulose acetate with trilobal cross section

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DE19951062C2 (en) 1999-10-22 2002-04-04 Rhodia Acetow Gmbh A high performance cigarette filter
CA2874570A1 (en) * 2012-07-25 2014-01-30 Celanese Acetate Llc Spinneret comprising tri-arc holes and tri-arc filaments produced therefrom
BR112014029617A2 (en) * 2012-07-25 2017-06-27 Celanese Acetate Llc filter; method; and smoking device
KR101455002B1 (en) 2013-06-28 2014-11-03 코오롱인더스트리 주식회사 Lyocell Material Cigarette Filter and Method for the Same
KR102211219B1 (en) * 2014-06-30 2021-02-03 코오롱인더스트리 주식회사 Lyocell Material with Noncircle Cross Section for Cigarette Filter And Manufacturing Method of the same
KR102211186B1 (en) 2014-12-31 2021-02-03 코오롱인더스트리 주식회사 Lyocell Material Cigarette Filter and Method for the Same
WO2018071571A2 (en) * 2016-10-11 2018-04-19 Eastman Chemical Company Fiber configurations for wellbore treatment compositions

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AU9154098A (en) 1999-02-10
CA2296690C (en) 2003-02-04
CA2296690A1 (en) 1999-01-28
DE19730485A1 (en) 1999-01-21
EP0996778B1 (en) 2003-09-17
DE59809658D1 (en) 2003-10-23
US6177194B1 (en) 2001-01-23

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