US 3111702 A
Abstract available in
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Description (OCR text may contain errors)
Nov. 26, 1963 R. M. BERGER 3,111,702
PRODUCTS FORMED FROM CONTINUOUS FILAMENTARY TOWS 3 Sheets-Sheet 1 Filed July 21, 1961 0 Pi 2 4 m Rmmann M. BERGER i 4 Y %M/W ATTORNEY R. M. BERGER Nov. 26, 1963 PRODUCTS FORMED FROM CONTINUOUS FILAMENTARY TOWS 3 Sheets-Sheet 2 Filed July 21, 1961 'IIIIIIIIIIIJ INVENTOR RIcHARD M. BzR ER ATTORNEY Nov. 26, 1963 R. M. BERGER v I ,1 0
PRODUCTS FORMED FROM CONTINUOUS FILAMENTARY TOWS Filed July 21, 1961 3 Sheets-Sheet 3 Fig. 7
I08 I00 M m "6 Fig. IO
INVENI'OR FIG-HARD M. BER ER law/MM ATTORNEY United States Patent 3,111,702. PRODUCTS FORMED FRGM CQNTWUOUS FILAMENTARY TQWS Richard M. Berger, Richmond, Va, assignor to US. Filtel Corporation, a corporation of New York Filed July 21, 1961, Ser. No. 125,868 6 Claims. (Cl. 15-563) This application is a continuation-in-part of application Serial Number 16,683 filed March 22, 1960, now abandoned, and of application Serial No. 56,189 filed September 15, 1960, now Pat. No. 3,095,343.
This invention relates to fibrous bodies having as a major constituent cellulose acetate fibres. More specifically, the invention is concerned with products formed from continuous filamentary tows having the filaments thereof randomly oriented primarily in a longitudinal direction.
The term continuous filamentary tow, as used in this specification and the appended claims, means a material such as that which results when filaments spun from a plurality of spinnerets are brought together and combined, preferably with filaments from other spinnerets, to form a continuous body of fibres randomly oriented primarily in a longitudinal direction. The term randomly oriented primarily in a longitudinal direction as used in this specification and the appended claims, is intended to describe the condition of a body of fibres which are as a whole longitudinally aligned, and which are, in the aggregate, in a parallel orientation, but which have short portions running more or less at random in a non-parallel diverging and converging directions.
Continuous filamentary tows of cellulose acetate fibres have been heretofore used and processed to adapt segments thereof for use as cigarette filters. Generally, the fibres of the tow are formed with spinneret devices, and the strands exiting from such spinneret devices are bunched together to form a raw tow which is wound into a bale for subsequent processing. The subsequent processing operations usually involve, in addition to unwinding of the raw tow, spreading apart of the fibres of the tow to provide a relatively thin fibre layer, tensioning of the fibres to eliminate the crimps therein, impregnating the fibre layer with a plasticizer to bind adjacent fibres together, gathering the bonded layer through a suitable funnel or the like to form a treated cylindrical tow, and then wrapping the treated tow in a suitable paper to form a rod. The paper-covered rod is then cut into small segments by ordinary cigarette cutting machine and cured, or maintained in lengths and cured.
Generally, the term curing has been used in the art to designate final bonding of fibres by the plasticizer. Such curing has been effected heretofore by letting the formed paper-covered segments of lengths of the treated tow age for an extended period of time unheated, or by subjecting the same to heat, as in an oven, for an hour or more to soften the plasticizer and permanently bond the tow fibres together.
While satisfactory cigarette filters have been made in accordance with the handling, treating and curing operations described in some detail above, certain disadvantages, as listed below, are inherent in such prior processes:
(1) With prior processes, non-uniform bonding of tow fibres cannot be detected until after a tow is formed into a rod and cured. Moreover, with prior processes, no compensation is made for nonuniformity in plasticizer distribution. Accordingly, it is believed that tows made by prior techniques which have been used do not, in fact, comprise uniformly-bonded fibre structures.
(2) With prior processes, tow rods are cut into segments while still somewhat soft. This appears to give rise to dislodging of individual fibres, uneven cuts, and in some instances mechanical problems.
(3) An extended time was required for curing a treated tow in accordance with prior practices because (a) the plasticizers do not bond well after initial set, and without heat, only effect some bonding after prolonged periods; and (b) oven heating of a treated tow must be extended before the central portions of the tow are affected, particularly when the tow is cured in lengths and/ or covered with a paper overwrap.
(4) The continuous filamentary tows treated in conformance with the procedures outlined above required a paper overwrap to maintain dimensional stability, because the tow, when so treated, prior to curing and, in most cases, after curing, in and of itself is pliable and stretchable and the fibres of the tow are not sufficiently bonded together to maintain a defined stable shape.
(5) Continuous filamentary tow segments as formed heretofore were limited to use as cigarette filters because (a) they required a paper overwrap, and the only widelyused, and thus economical, overwrap equipment was the cigarette machine; and (b) because paper or other dimensionally-stable overwraps prevent utilization of the tow segments for certain applications.
While the processes described above are believed to be representative of those in most widespread use presently, and accordingly, while the stated disadvantages are believed to be accurate, it should be understood that others have attempted to produce dimensionally stable tow products which do not require an overwrap. However, the suggestions made in this particular regard appear to require either (a) the application of a cellulose derivative in dilute aqueous solution to the tow, the resultant com paratively expensive operation of removing a substantial quantity of water from the tow, or (b) the utilization of a fibre mixture including adhesive and non-adhesive fibres, and the resultant limitations on fibre size and fibre constituents.
I have discovered that all of the above stated disadvantages and limitations can be overcome and many advantages can be obtained by following the prior art banding, tensioning and impregnating practices to form a raw tow into a plasticizer-impregnated layer of continuous uncrimped filaments, and then departing from the prior art by curing the continuous filamentary tow simultaneously with, or immediately after, gathering of such impregnated layer into a final rod shape.
Still a further primary object of the present invention is to provide a filamentary tow product wherein there is complete and uniform bonding of all adjacent fibres within the tow and dimensional stability of the finished tow without overwrap, whereby an unwrapped tow rod can be economically formed with various diameters and cut into segments suitable for use as adsorbers or applicators or container filter stoppers,'as well as improved cigarette and cigar filters, or other smoke filters.
Yet another and still further primary object of the present invention is to provide an improved inexpensivelymanufactured fibre adsorber and/ or applicator which has all of the advantages of ordinary adsorbers, and which, in addition, provides for controlled fluid dispensing and is not subject to linting or fuzzing.
Still further specific, yet particularly important objects of the present invention are: (a) to provide a tow product having a dimensionally stable shape without an overwrap which product is formed entirely of non-adhesive fibres; (b) to provide such a tow product which is not limited in fibre size and which does not require a binder fibre; and (c) to provide such a product which does not require a squeezing water removal step in fabrication.
The new and improved product of the invention is one made in accordance with the process herein described,
and comprises basically a body of continuous filaments randomly oriented primarily in a longitudinal direction, the major portion of the filaments being cellulose acetate fibres, the fibres being bonded to adjacent fibres by a plasticizer, the peripheral layer of fibres providing a stiffened peripheral shell for the body, and the body being adapted for use as a filter and/or applicator and/ or adsorber.
The various aspects of the invention will be better understood, and objects other than those specifically set forth above will become apparent, when consideration is given to the following detailed description of the illustrative and preferred embodiments of the invention. The description refers to the annexed drawings, wherein:
FIGURE 1 presents schematically a production-line assembly of stations past which a continuous filamentary tow can be moved for treating in accordance with the method of the invention; 7
FIGURE 2 is a cross-sectional side view of an apparatus provided by the invention for handling and steamtreating a tow, in accordance with the method of the invention;
FIGURE 3 is a transverse cross-sectional View of the apparatus shown in FIGURE 2, FIGURE 3 having been taken on the line 3-3 of FIGURE 2;
FIGURE 4, like FIGURE 3, is a transverse cross-sectional view in the apparatus shown in FIGURE 2; however, FIGURE 4 is taken on line 4-4- of FIGURE 2;
FIGURE 5 is a cross-sectional side view of an apparatus provided by the invention for handling and airtreating a tow in accordance with the method of the invention;
FIGURE 6 is a transverse cross-sectional view of the apparatus shown in FIGURE 5, FIGURE 6 having been taken on the line 6-6 of FIGURE 5;
FIGURE 7 is a cross-sectional side view of an apparatus provided by the invention, which is similar to that shown in FIGURE 2, but which in addition incorporates a central tow passageway forming a member so that hollow tows can be produced thereby;
FIGURES 7 (a), (b) and (c) are schematic cross-sectional representatives of alternative core passageway and tow passageway forming member shapes;
FIGURE 8 is a cross-sectional side view of a container housing an adsorber and applicator assembly constructed in accordance with the invention, and made from components processed in accordance with the invention;
FIGURE 9' is a cross-sectional side view of a cigarette provided with a filter made in accordance with the invention; and
FIGURE 10 is a cross-sectional side view of a cigar provided with a filter made in accordance with the inven tion.
For purposes of clarity and to facilitate a complete comprehension of the invention, the method, apparatus, and product phases are considered hereinbelow under separate headings.
General Method In the present description, it is assumed that a continuous filamentary tow has been formed from. spinneret devices by any one of the established techniques being widely used in the industry today for formation of cigarette filter tows, and that the same has been wound upon a bale for storage whereby it can be withdrawn from the bale as desired for further processing. Such a tow is referred to herein as a raw or untreated tow, and, as 'known to workers in the art, the fibres of a raw or untreated tow are normally crirnped and not bonded together.
(A) Initial treatment-In accordance with the invention, in accordance with prior art practices, and as shown in FIGURE 1, the raw tow 10, in crimped form, is taken from a supply bale 11 through an elevated banding device 12 which comprises multiple jets disposed to blow air under pressure against the raw tow so as to separate the individual fibres thereof. The banded tow then passes over a guide roller 13 to two spaced pairs of rollers 14, 15 with the vibrator 16 disposed therebetween for alternately applying tension to, and relaxing the tow so that it becomes completely open, i.e., the fibres are generally separated and at least substantially uncrimped. From the rollers 15 the tow passes another banding device 17 which is similar to the device 12 and serves to spread the tow into a thin fibre layer. The fibre layer is then passed through a plasticizing device 18 wherein a suitable plasticizer is sprayed by jets onto the fibres.
(B) Curing the tom-Although the tow is preferably I initially processed according to the known techniques destation 18 is fed to a first curing station wherein the fibres are simultaneously heated and gathered together. Disposed at this first curing station 19 is a heating and shaping apparatus which may comprise, as shown in FIG- URE 1, a tube or nozzle 19 having a funnel-shaped mouth or entrance 19a leading into the forming passageway 19b of the tube. The passageway 1% has a diameter corresponding to the diameter desired for elements which are to be produced, and serves to shape the tow into a rod. Steam can be admitted into the tube through a suitable inlet 20 to hasten and more uniformly and adequately heat the fibres and plasticizer of the tow during its passage through the tube, or, alternatively, a mixture of heated or vaporized water and plasticizer may be sprayed on the tow during its passage through the first curing station 19 for the same purpose. In any event, a vaporized heated gas is passed onto the tow, or, more particularly, the plasticizer-impregnated layer of tow fibres, as such layer is gathered into a rod-like formation within the confined area defined by the tube 19'. Preferably, steam is used for the first curing treatment, and such steam is passed onto the confined area defined by the tube under pressure and at an angle with respect to the longitudinal axis of the tow whereby the steam travels counter-current to the direction of movement of the tow. Although I have found that a substantial increase in bonding of the tow fibres is achieved by merely subjecting the tow to steam immediately after the layer of impregnated fibres is gathered into a rod-like formation, and while the same is confined, I have found also that more uniform bonding of the fibres and greater dimensional stability of the tow can be obtained when the steam is directed onto the tow counter-current to the direction of the movement thereof, and at a -degree angle with respect to the longitudinal axis of the tow whereby the steam passes through the tow and out of the tow entrance end of the first curing station so that the incoming impregnated layer of fibres is heated as it is gathered into a rod-like structure.
While FIGURE 1 presents schematically the type of apparatus which may be used as the first curing station, preferably a gathering and steam-treating apparatus such as that described in detail hereinbelow and shown in FIGURE 2 is used at the first treating station. The pressure of the steam being passed onto the tow, and the speed at which the tow is moved to the first curing station will vary to a certain extent with the apparatus being used and/or other conditions. However, when the preferred embodiments of the invention are adopted, I have found that suitable bonding of the fibres can be achieved at tow speeds of between -l00 meters per minute with steam being introduced at a rate of between six pounds per hour to ten pounds per hour with tows adapted to be out into segments for use as cigarette filters. Preferably, the steam introduced is saturated at an initial pressure of 20 pounds p.s.i.g.
The tow, in the form of a rod-like structure as it emerges from the first curing station, is generally selfsustaining in shape and in cured condition. The term cured as used in the art means a tow obtained from a process by which the fibres of the tow are bonded to adjacent fibres after the fibres have been gathered into a rodlike structure. The process of the present invention prepares a cured tow more readily and with improved characteristics over those of the prior art.
A tow which has left a first curing station of a production line operated in accordance with the present invention can be passed directly to an ordinary cigarette machine cutting apparatus and severed into segments, and there is no need to apply a paper overwrap thereto. However, I have found that once the tow passes the first curing station and is a cooperating mass within the confines of a stiffened peripheral layer, a superior product can be obtained by immediately fixing the dimensions of the rod without developing further stiffness or reducing the total fibre surface by fusion of the fibres.
Thus, notwithstanding the fact that a tow which has been passed through a first curing station, such as that designated by numeral 19, possesses some dimensional stability and can be severed into segments, the preferred embodiments of the invention provide for subjecting the tow to a second curing action immediately after its emergence from the first curing station.
More specifically, in accordance with the preferred embodiments of the invention, the tow which emerges from the first curing station 19 is fed directly to a second curing station 50 wherein dry air is passed onto the tow and through the tow to set the fibre components and plasticizer components of the tow so that it has complete dimensional stability without excess stiffness or fibre fusion. Preferably, the air which is passed onto the tow at the second curing station 50 is perfectly dry, has a temperature of 90 F. or below, and is maintained under a pressure of between 50 and 100 p.s.i.g. Moreover, for optimum results, the air should be passed onto the tow counter-current thereto and at an angle of substantially 7 degrees to the longitudinal axis of the tow. A suitable apparatus for air-treating the tow at the second curing station is shown in FIGURE 5 and described in more detail hereafter.
The steam streams and air streams are preferably passed onto the tow circumferentially thereof, and the steam-injecting apparatus (best shown in FIGURE 2) as well as the air-injecting apparatus (best shown in FIG- URE 5) provide for passing the respective gaseous streams onto the tow at spaced points about the periphery thereof so that uniform treating is achieved.
A tow which has been passed through a first and second curing station and treated as described above not only has substantially uniformly-bonded fibres within the tow, but, in addition, has a stiffened peripheral layer or crust which gives the tow complete dimensional stability. As the tow leaves the first curing station 19, it has some dimensional stability; however, it is not completely set, and thus pulling of the tow, as suggested above, can result in some deformation thereof, particularly when the tow has a substantial diameter. In addition, as also suggested above, the fibres of the tow can become fused to reduce surface area and cause excess stiffness. For this reason, in accordance with the invention, the second curing station is so disposed that the tow is cooled therein to essentially room temperature within .02 to .05 second after it emerges from the first curing station. By minimizing the time for travel between the first and second curing stations, any tendency of the tow to deform is minimized, and the fibre components and the plasticizer components of the tow are set without excess fibre fusion, and in a cellular formation, or to give a cellular product. The air treatment not only insures against undesirable stiffness, but also cools and dries the tow so that it can be immediately wrapped, if desired, without causing deformation and wrinkles in the overwrap.
From the foregoing discussion, it should be apparent that a tow which is treated in accordance with the present invention has uniformly-bonded fibres and complete dimensional stability as it leaves the second curing station. Moreover, it should be apparent (a) that no subsequent operations need be performed on the tow except for the cutting thereof into segments; (b) that the uniformly-bonded dimensionally-stable tow is produced as rapidly as the tow is banded, tensioned, impregnated, and gathered; and (c) that the linear tow speeds can be at least as great as those encountered in conventional production lines operated in accordance with prior art practices. Moreover, it should be apparent that no paper overwrap is required prior to severing of the finished tow into segments. Of course, it may be desired in some instances for special purposes to provide a special exterior coating on the tow, and such may be done without departing from the invention by using an annular brush or spray such as that schematically shown in FIGURE 1 and designated by the numeral 21. The formed tow can then be fed to a cutter 24, severed into segments such as those designated by the letter S, and stored in a suitable container 25.
(C) Tow materials.--Various materials capable of being formed into a continuous tow comprising body of fibres randomly oriented primarily in a longitudinal direction may be treated in accordance with the method of 'the invention and used to form products provided by the invention. It is an important feature of the invention, however, to form the continuous filamentary tow from cellulose acetate fibres, and according to the preferred embodiments of the invention, any products produced comprise at least 50% cellulose acetate fibres. For certain 'uses, and to achieve certain filtering and/or adsorbing and/or liquid-holding properties, the cellulose acetate fibres may be mixed with other materials, such as, cellulose, viscose, cotton, cellulose acetate-butyrate, cellulose propionate, activated carbon, asbestos, metal fibres, wood fibres, and sawdust, and/or mixtures thereof.
(D) Suitable plasticizers.While the particular plasticizer which is sprayed onto the spread layers of tow fibres at the plastioizing station 18 may be any one of the known types of plasticizers which will serve to suitably bond together the continuous filaments being treated, preferably the plasticizer used is one selected from the group consisting of diethoxyethyl phthalate, dimethoxyethyl phthalate, triethyl citrate, tributyl citrate, tricresyl phosphate, glycerine triacetate, glycerine tripropionate,
triphenyl phosphate, ethyl phthalyl, ethyl glycolate, acetyl tr-iiso hexyl citrate, acetyl triethyl citrate, dimethyl phthalate, diethyl phthalate, triethyl phosphate and tribetachlorethyl phosphate.
(E) Fibre and tow denier.-The denier of individual fibres and the total denier of the tow may be varied as desired to achieve any given finished tow characteristic. I have found, however, that best results can be obtained when the individual fibre denier ranges between 1.6 and 16, and the total denier of the tow ranges between 37,000 and 500,000. Of course, this includes the total denier range of 37,000 to 100,000 normally used in the production of cigarette filters.
(F) Particular material proportions and characteristics.Preferably 5%15% plasticizer by weight of the tow is applied in the aforesaid manner, and bonding is achieved without any squeezing of the tow. The bonding resulting from release of heat from the applied steam, at most creates an insignificant amount of condensed water, and the drying step performed in accordance with the invention eliminates such water. It is important to note that the various types of fibres which may be used, as set forth in paragraph (C) above, are non-adhesive. Bonding is achieved'by the plasticizer and controlled treatment steps.
Apparatus with the method of the invention are shown in FIGURES 2 through 6.
(A) Steam-injecting apparatus.The steam-injecting apparatus, which is best shown in FIGURE 2, comprises a housing 100 at least partially open at either end thereof and defining a treating chamber 102 extending between the openings '104 and 1116 at opposite ends of the housing 100. A core member 108 is disposed within the chamber -102 in juxtaposition to the forward end 110 of the chamber. The core member has a tow passageway 112 therethrough which extends between the ends of the housing, and the core member also has fluid passageways 114 therein which extend angularly into the tow passageway 112. A closure member 116 is provided for closing the rear end of the chamber or the end opposite the end designated by numeral 110. The closure member has a tow passageway 118 therethrough. Cooperating means are provided on the housing 100 and closure member 116 for removably securing the closure member in position. Preferably such cooperating means take the form of screw threads 120 which allow for removably securing the closure member to the housing with the tow passageway 113 in the closure member coaxial with the tow passageway 112 in the core member. An inlet conduit 122 extends through a side wall of the housing and communicates with a chamber passageway 124 whereby the conduit and chamber passageway serve as means for providing communication between the exterior of the housing 100 and the fluid passageways 114 in the core member. With this general construction, the tow 10, when moved through the tow passageways 118 and 1 12, can be subjected to fluid introduced through the inlet conduit 122 while the tow is confined within the passageways.
The closure member 116 is an elongated funnel-type member having a tow passageway with a first tapered portion 118a leading into a second portion 11% of uniform cross section. The tow passageway 112 in the core member 108 has a uniform cross section throughout its length and this cross section as shown, is slightly smaller than the cross section of the second portion 11812 of the tow passageway in the closure member 116.
The portion of the passageway 11 8 which receives the impregnated fibre layer leaving the plasticizing station 18, namely, portion 11811, is tapered to provide a funnel-like structure leading into the portion 1 1812 of uniform cross section. Thus, the impregnated fibre layer is, as the tow is pulled through the apparatus of FIGURE 2, gathered into a rod-like structure.
After the tow has been gathered into the rod-like structure, it passes next through the core member 108 which, preferably, as shown in FIGURE 2, has a tapered recess leading into the tow passageway 112. The core member may have any suitable outline conforming with the cross section of the chamber 1132f; however, preferably, both the chamber and the core member are generally cylindrical in shape. The core member is provided with end flange projections such as those designated by numeral 132, and these flange projections serve as means for supporting the core member in spaced relation to the side walls of the chamber to provide the chamber passageway 1-24 between the core member and the side walls of the chamber. The fluid passageways 114 communicate with this chamber passageway, as does the inlet conduit 122, and thus steam passed into the inlet conduit 122 passes through the fluid passageways 114- in the core member and onto the tow in the direction counter-current to the movement of the tow. Preferably, the fluid inlet passageways 114 make an angle A of 45 degrees with respect to the longitudinal axis of the tow or the longitudinal axis of the tow passageway in the core member. Steam which is so passed onto the tow travels through the tow due to the pressure within the chamber in a direction opposite to the direction of movement of the tow. Thus, steam which enters through the inlet conduit 122 is caused to move through the tow rearwardly of the fluid passageways 114 and into the tow passageway of the closure member 116. It will be remembered that this closure member 116 has a tow passageway 118 which serves to gather the tow and, accordingly, the steam which is moving rearwardly through the tow serves to heat the fibres of the tow and plasticizer impregnated thereon as the same is being gathered into a rod-like formation. Preferably, this treatment takes place as the fibres of the tow are assuming their ultimate disposition, or, more particularly, as the fibres are moving from the tapered portion of passageway 118 into the portion of uniform cross section.
To release air pressure within the tow, as it is assuming its ultimate dimension, the closure member 116 is provided with a series of escape passage-ways 141] extending between the tow passageway 118 and the exterior surface of the closure member. Preferably the escape passageways 140 slope into the tow passageway 118 and communicate with the same at least substantially at the junction of the tapered portion 118a and the portion 11% of uniform cross section.
The threaded coupling of the closure member 116 with the housing serves to provide an effective seal at the rear end of the treating chamber 102, and the bearing of the forward face 109 of the core member against the front wall 110 of the housing serves to provide an effective seal at the forward end of the chamber. Preferably, the core member 1118, in addition to having the features described above, also is provided with a forwardly-extending nozzle portion 15%} through which a continuation of the tow passageway 112 is provided. The nozzle portion has a peripheral shape and size whereby it engages the surrounding walls of the opening 104 in the forward end of the housing 100. It has been found that with this construction a sufficiently effective seal is provided, but it should be understood that suitable sealing washers and/ or packings may be incorporated in the apparatus of FIG- URE 2 if desired.
It should also be understood that while I have shown a cylindrical core member and a cylindrical chamber, the chamber and core member may be made square or rectangular or of any other suit-able shape. Similarly, while the inlet conduit 122 has been shown as attached to a flanged bore in the housing side wall, to provide an inlet conduit, any other suitable form of inlet conduit which can be coupled with a source of steam or other heated vapors may be used.
Although the steam-injecting apparatus described above is suitable for many applications, I have found that generally the same type of apparatus can be used, with slight modification, to provide a tow having a passageway running therethrough. In this connection, particular attention is directed to FIGURE 7, wherein the modified form of apparatus for producing a tow having a central passageway therein is shown. The FIGURE 7 apparatus includes the same basic components as the apparatus of FIGURE 2, namely, a housing 1%, a core member 108, and a closure member 1116. The tow passageways, steam inlet passageand the core member, and the tow passageway in the closure member 116. The rear portion of the tube 400 is preferably bent upwardly, as shown, and the tube is apertured. Steam is passed into the entrance end 401 of the tube 400, just as steam is passed into the inlet conduit 122 of the housing 100. The amount of steam introduced, pounds per hour per square inch cross section of the tow, and the steam saturation, can be the same as for the steam introduced through the inlet conduit 122.
The tube 4% is supported centrally within the core member 108, or more particularly the tow passageway 112 thereof, by the fibres of the tow which are passing through the apparatus. To insure central disposition of the tube 469, the same can be initially adjusted if necessary.
The tube 400 as shown is circular in cross section, however, it should be understood that the tube can be square in cross section, or oval in cross-section, or of any other cross-sectional shape desired. Preferably, the shape of the tube corresponds to the shape of the passageway 112 in the core member 108 but the cross-section of the tube can differ from the cross-section of the core passageway 112 if desired.
The apparatus shown in FIGURE 7, as suggested, includes a tube 400 having a circular cross-section. Figure 7(c) shows a transverse cross-section of the core passageway 112 and the tube 400 as the same would appear when a circular tube and circular core passageway construction is utilized in the apparatus of FIGURE 7. FIG- URES 7(a) and 7(b) present alternative core passageway shapes and alternative tube cross-section shapes. Prime numerals are used in FIGURES 7(a) and 7(b) to designate corresponding components.
(B) Air-injecting apparatus-The air-injecting apparatus of the invention is constructed in generally the same way as the steam-injecting apparatus, as will be apparent from a review of FIGURES and 6. However, instead of providing a funnel-type closure member at a rear end of the housing, an elongate plug 160 is provided and the elongated tow gathering passageway 118 such as shown in FIGURE 2 is replaced by a slightly tapered recess 162 on the end of plug 169 leading into a tow passageway 164 of uniform cross-section. Of course, the plug 159 need not be elongate; however, the elongate construction is preferred because it is more easily handled.
The core member 10841 of the air-injecting apparatus is substantially identical with the core 108 of the steaminjecting apparatus; however, preferably two sets of fluid inlet passageways are provided in the air-injecting apparatus. More specifically, in addition to the fluid inlet passageway group 114a, there is provided a second inlet fluid passageway group 115. The inlet passageway groups each comprise a series of individual fluid passageways and the passageways in both groups are preferably disposed at a 45-degree angle with respect to the longitudinal axis of the core member tow passageway and slope toward'the rear end of the housing or toward the closure member whereby fluid passed into the housing is directed counter-current to the direction of movement of the tow through the housing. The passageway groups are preferably offset. In FIGURES 5 and 6, prime numerals have been used to designate components of the air-injecting apparatus which correspond directly with components of the steam-injecting apparatus shown in FIGURES 2-4.
The tow passageways in the core members, and the uniform cross section portions of the tow passageways in the closure members correspond exactly with the outer contour of the rod-like tow structure which is being produced. This is an important feature of the invention, because, as explained above, the method of the invention provides for confining the tow during the steam treating and air treating operations whereby it obtains the dimensional stability and uniform bonding characteristics desired. Thus, when the operation is to be carried out on a tow having a larger or smaller diameter than that shown in FIGURES 2-6, it is necessary to change the size and/ or shape of the tow-receiving passageways. With the apparatus provided by the present invention, this is easily achieved. The closure members can be made with passageways of various sizes, as can the core members. Accordingly, when it is desired to use the apparatus for processing different size tows, it is only necessary to remove the closure members, remove the cores, insert in each housing a different core member having a tow passageway of appropriate size, and then tighten on a closure member also having the appropriate size tow passageway. There is no need to disconnect any of the steam conduits or any of the air conduits, nor is it necessary to in any way move the housings.
PRODUCT A tow which has been processed in accordance with the method of the invention as described above, and which has been passed through suitable apparatus for carrying out the method such as that also described above, generally is cut into segments or lengths for future use. The segments, as explained, may be used for smoke filter, valve filters, stopper plugs, adsorbers, and/ or applicators, as well as for other purposes outlined in detail hereinabove. Notwithstanding this fact, it is important to understand that one of the principal features of the invention is the provision of (a) an improved cigarette filter, and (b) the provision of a new type of adsorber and/ or applicator.
The improved cigarette filter and the new type of adsorber and/ or applicator generally comprise a body form from continuous fibres randomly oriented primarily in a longitudinal direction and having a stiffened peripheral layer or crust formed of the same materials as the interior portion of the body.
The fibres of the body are preferably cellulose acetate; however, cellulose acetate and other materials set forth hereinabove as being suitable tow materials can be combined to provide the final product. Of course, in accordance with the invention, the body also includes a suitable plasticizer, and preferably one selected from the group of plasticizers set forth above. However, in accordance with the preferred embodiments of the invention, the ultimate product consists only of the continuous fibres randomly oriented primarily in a longitudinal direction and the plasticizer with which the fibres are impregnated. The stiffened peripheral layer consists of exactly these materials, and the amount of plasticizer adjacent fibres of the stiffened peripheral layer appears to be no greater than the amount of plasticizer adjacent fibres within the interior of the body.
An example of a dispenser formed in accordance with the present invention is shown in FIGURE 8. The dispenser includes any suitable housing or containing means such as that designated by numeral 200. Preferably, however, the containing means is provided with a nozzle 262 and a closure cap of some type such as that designated by numeral 204. Disposed within the containing means is an adsorber 206 which comprises a body of continuous cellulose acetate fibres randomly oriented primarily in a longitudinal direction and treated in accordance with the method of the present invention. The adsorber 206 is coupled with an applicator 268 having the rear end thereof in contact with the adsorber forward end. The applicator 20-8 also comprises a body of continuous cellulose acetate fibres randomly oriented primarily in a longitudinal direction and treated in accordance with the present invention. However, the total denier of the applicator 208 and the denier of the fibres thereof differ from the total denier and the denier of the fibres of the adsorber 206. The adsorber 206 has a main function of holding as much fluid as possible, while the applicator 268 has a main function of dispensing or applying the fluid uniformly in controlled amounts. Thus, the denier of the applicator is selected to provide suitable fluid 11 control dispensing characteristics, whereas the denier of the adsorber 206 is selected to provide desired liquidholding characteristics. The applicator 208 and adsorber 206 are filled by dipping or injection with a material to be dispensed, such as, for example, paint, perfume, or antiseptic.
Another example of a product which utilizes the invention is presented in FIGURE 9. In that figure the numeral 300 is used to generally designate a cigarette comprising a paper overwrap 302, a body of tobacco 304, and a cigarette filter element 366. The cigarette filter element 306 comprises a segment of a tow treated in accordance with the present invention and thus has a stilfened peripheral layer or crust. The cigarette filter element 306 is coupled with the cigarette paper 302 directly and there is no intermediate layer of paper between the periphery of the filter 306 and the outside paper covering 302 of the final cigarette.
Still another example of a product which utilizes the invention is presented in FIGURE wherein the numeral 500 generally designates a cigar. The cigar comprises a tobacco fill 502 and a leaf-tobacco overwrap 504. Within the tobacco overwrap 504, at one end of the cigar, there is provided a cigar filter 506, which filter comprises a segment of a tow treated in accordance with the present invention.
Examples trol drafting rollers as illustrated in the accompanying drawing (FIGURE 1) for the purpose of opening the tow and breaking up bundles therein. The open tow 'was thence directed to an air jet bundle breaking and banding device of a type such as that described above. Air jets from below the tow operating at a pressure of 1.5 pounds gauge were directed against the tow and succeeded in further breaking any individually formed bundles therein and opening or banding the tow to provide a fibre mass of web-like form, approximately 12 inches in width. Thence, the opened and handed fibre was sent through a chemical conditioning station or plasticizing station where it was continuously sprayed with 8% of glycerine triacetate plasticizer. The sprayed, webbed fibre layer was then passed through a steamtreating apparatus such as shown in FIGUREZ at a linear tow speed of 50 meters per minute and approximately 6 pounds per hour of steam was introduced through the fiuid inlet conduit of the housing. The steam was saturated at an initial pressure of pounds per square inch gauge and passed through the tow softening the same and uniformly bonding the fibres of the tow as it was gathered together in the apparatus. The tow was then moved from the steam-treating apparatus at the same linear speed and through an air-treating apparatus such as shown in FIGURE 5, whereby within .03 second after leaving the steam-treating apparatus it was cooled to essentially room temperature. Air having a temperature of approximately 90 F. was introduced into the air-injecting apparatus of FIGURE 5 through the inlet conduit of the housing at a rate of about 5 cubic feet per minute and under an initial pressure of 80 p.s.i.g. The tow after leaving the air-injecting apparatus was cut into segments of suitable length, for future use as cigarette filters.
Example 2.A tow was treated exactly as set forth 12 in Example 1 and then the segments were used to form a filter cigarette constructed as shown in FIGURE 8.
Example 3.--A tow was treated exactly as set forth in Example 1 except the tow was cut into segments approximately two inches in length and suitable for use as applicators.
Example 4.A tow was treated exactly as set forth in Example 1 except the glycerine triacetate plasticizer was replaced by 7% acetyl triiso hexyl citrate.
Example 5.A tow was treated exactly as set forth in Example 1 except the tow was formed of 60% cellulose acetate fibres and 40% cotton fibres.
Example 6.-A tow was treated exactly as set forth in Example 1 except it was moved through the steamtreating and air-treating apparatus at the rate of 100 meters per minute and 10 pounds of steam per hour was introduced through the inlet to the housing.
Example 7.A tow was treated exactly as set forth in Example 1 except the same was moved through the steam-treating and air-treating apparatus at the rate of 75 meters per minute and 9 pounds of steam per hour was introduced through the inlet to the steam-treating housing.
Example 8.-A tow was treated exactly as set forth in Example 1 but the denier per fibre and the total denier of the tow was varied as shown in Table I, and the fibre weight was determined. After the tows had been treated as set forth in Example 1, segments of each tow were dipped in ink, and the excess ink was allowed to drip off. The segments were then weighed to determine the ink adsorbed.
TABLE I Fibre Con- Weight Ink Ad- Ra io Sample No. struetion Fibre (g.) sorbed (00.) (cc./g.)
(denier) Comparison example-A tow was treated exactly as set forth in Example 1, except no steam was introduced into the steam inlet of the steam-injection apparatus, and no air was introduced into the air inlet of the air injection apparatus. The denier per fibre and total denier of the tow was adjusted as set forth in Table I, and the fibre weight was determined. The tow emerging from the air-injecting apparatus was cut into segments. The segments of the tow treated in accordance with this example were then dipped in ink, and the excess ink allowed to drip oil. The ink saturated segments were then weighed, and the results were as set forth in Table II below.
TABLE II Fibre Con- Weight; Ink Ad- Ratio Sample No. struction Fibre (g.) sorbed (00.) (cc/.g.)
(denier) The tow produced in all of the examples except for the comparison example had a stiffened peripheral layer and complete dimensional stability. Moreover, as is apparent from a review of the results set forth in Tables I and II above, the tow segments treated in accordance with the present invention had almost twice the ink-holding power of comparable fibre construction segments treated in accordance with the comparison example. The ink-holding power of sample 1 of Table II was increased because of the use of a fibre having a very small denier. Thus, the method of the invention not only yielded the result of providing a completely dimensionally-stable tow having a stiffened peripheral crust, but in addition it provided the result of increasing the liquid-holding properties of a continuous tow of fibres randomly oriented primarily in a longitudinal direction.
Although detailed qualities have been used in the foregoing examples, it has been found (a) that the particular plasticizer and amounts thereof are not critical, so long as the plasticizer is compatible with the tow fibres, and (b) that the method of the invention can be carried out within the following ranges which yield preferred results:
(1) Tow speed: 2 to 100 meters per minute.
(2) Steam introduced: 5 lbs. per hour to 500 lbs. per
hour per square inch cross-section of the tow.
(3) Steam saturation: 100% at initial pressure of between p.s.i.g. and 70 p.s.i.g.
(4) Cooling time after leaving steam-treating apparatus:
preferably .02 to .05 second.
(5) Air temperature: preferably not over 90 F.
(6) Air introduced for cooling: preferably 10 cu. ft. per
minute per square inch of tow cross-section.
After reading the foregoing detailed description of the various aspects of the present invention, it should be apparent that the objects set forth at the outset of this specification have been successfully achieved. Various modifications of the illustrative embodiments of the invention presented herein above may become apparent to those of ordinary skill in the art. Accordingly,
What is claimed is:
1. An article comprising a body of continuous nonadhesive filaments containing at least 50% cellulose acetate filaments and randomly oriented primarily in a longitudinal direction, said filaments carrying a plasticizer thereon, said plastitizer bonding said filaments at least substantially only at spaced apart junctures therebetween throughout said body, said body having a stiffened peripheral layer and a softer inner portion within the confines of said layer, said layer and said inner portion being substantially equally porous.
2. The organization of claim 1 wherein said article is a cigarette filter.
3. The organization of claim 1 wherein said article is a cigar filter.
4. The article of claim 1 wherein the amount of plasticizer carried by said filaments of said peripheral layer is at least substantially equal to the amount of plasticizer carried by the other filaments in said body.
5. A dispenser comprising 2. containing means; an adsorber carried within said containnig means; an applicator engaging said ads-orber and projecting outwardly from said containing means; said adsorber and said applicator each comprising a body of continuous filaments containing at least cellulose acetate filaments randomly oriented primarily in a longitudinal direction, said filaments carrying a cellulose acetate plasticizer thereon, said plasticizer bonding said filaments, each said body having a stiffened peripheral layer formed of said filaments carrying said plasticizer and a softer inner portion within the confines of said layer formed of said filaments carrying said plasticizer, the amount of plasticizer carried by said filaments of said peripheral layer being no more than substantially equal to the amount of pla'sticiezr carried by the other filaments of said body, said layer and said inner portion being substantially equally porous.
6. A dispenser as defined in claim 5 wherein said continuous filaments of said applicator have a different denier than said continuous filaments of said adsorber.
References Cited in the file of this patent UNITED STATES PATENTS 48,119 Walton June 6, 1865 2,334,253 Davis Nov. 16, 1943 2,610,769 Goetz Sept. 16, 1952 2,676,349 Vosburg Apr. 27, 1954 2,688,380 MacHenry Sept. 7, 1954 2,728,346 Crawford et al Dec. 27, 1955 2,900,988 Crawford et al Aug. 25, 1959 3,079,930 Cobb et al. Mar. 5, 1963 FOREIGN PATENTS 860,392 Great Britain Feb. 1, 1961