CA2059042C - Method of producing shaped cellulosic bodies - Google Patents
Method of producing shaped cellulosic bodies Download PDFInfo
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- CA2059042C CA2059042C CA002059042A CA2059042A CA2059042C CA 2059042 C CA2059042 C CA 2059042C CA 002059042 A CA002059042 A CA 002059042A CA 2059042 A CA2059042 A CA 2059042A CA 2059042 C CA2059042 C CA 2059042C
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- bath
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B11/00—Preparation of cellulose ethers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J5/00—Manipulators mounted on wheels or on carriages
- B25J5/007—Manipulators mounted on wheels or on carriages mounted on wheels
-
- 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
- D01D5/06—Wet spinning methods
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
- C08J2301/02—Cellulose; Modified cellulose
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Textile Engineering (AREA)
- Materials Engineering (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Health & Medical Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Robotics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- Artificial Filaments (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
Abstract
A cellulosic shaped body, for example, a foil or fiber is produced by passing a spinning solution from an orifice into a spinning bath. The ratio of the withdrawal velocity from this spinning bath to the orifice emergence velocity is held at no more than 1 and after emergence from the spinning bath, the body is stretched.
Description
E
MET~iUD OF PROD~(TCZNG SI~APED CEL~JLOSTC HO~T~:S
SPECII~xCAT~ON
Kiel ~f the)Enventi_on Our pxesent invention relates to a method of producing shaped cellulosic bodies in which a cellulosic amine oxide solution is extruded from a shaping orifice, e.g. a spinneret nozzle or a shaping die, and is passed into a coagulating or precipitating bath from which the Shaped object is withdrawn. Typical Shaped objects within the purview of the present invention are filaments or fibers lp and sheets or films.
~_Se.~~.~~L~~ ~! ~h~ nVA X11 =t is known to produce high polymer fibers with good fiber and film characteristics when, within the elongated body which is fabricated, a fiber structure is generated (see the Ullmann Encyclo-lg pedia, 5th Edition, Volume A10, page 456). Zt is desirable and, indeed, necessary to align micro-oriented regions, such as fibrides, in the fiber along the fiber axis. The alignment or orientation can be effBCted by various fabrication techniques and can dapend upon the physical or physical-chemical processes to which the fiber or film is subjected. xn many cases, this orientation can be effected by a stretching.
7856wMR
The process steps and the conditions in which and under which this stretching is caxried out has an impact upon the fiber properties whzch are produced, zn melt spinning, the fiY~ers are stretched in a hot plastic state while the molecules are mobile.
Soluble polymers can be wet spun or dry spun. zn dry spinning, the stretching is effected while the solvent is removed or is evaporated. Extruded Fibers which axe coagulated in a precipitating or coagulating bath are commonly stretched during the coagulation.
Processes of these types are well known and are widely described. zn all of these cases, however, it is important that the transition From the liquid state (independently of whethex this state is a melt state or a solution state) to the solid state be so e!leoted that during the filament formation, an orienxation of the polymer chains or polymer chain packetra, referred to as gibride~s, librilts or the like, is brought about.
xo inhibit the flash evaporation of a solvent from a filament during dry spinning, there are numerous possibilities. However, the problem of extremely rapid coagulation o! polymers during wet spin-ning, as is the case with the spinning a! csilulosio amin~ oxide solutions, has been solved heretoEars only by a combination of dry spinning and wet spinning.
zt is, therefore, known to pass solutions of polymers into the coagulation medium via an air gap. In EP~A~2~~ 672, in the production of aramid fibers which are brought into a noncoagulating medium via an air gap, stretched and then subjected to coagulation, there is a combination of features of both dry and wet rpinning.
20~904~
In the East German patent 218 ~.~7., the spinning l:rom cellulose zn amine oxides is effected via an air gap and precautions must be taken to prevent adhesion of the objects produced. U.S.
patent 4,501,886 describes the spinning of a solution of cellulose triacetate using an air gap. In U.S. patent 3,414,645, 'the production of aromatic polyamide objects from solution is effected in a dry-wet spinning process.
In all of these processes, an orientation is effected in the air gap if only because the downwardly emerging solution from the la orifice is at least stretched by the gravitational force on the solution. The orientation effected by the gravitational action can be increased when the extruder velocity, they velaaity at which the solution emerges from the orifice, and the withdrawal speed of the fiber passing through the coagulating bath are so adjusted that 15 further stretching occurs. A process of this latter typ~ is described in Austrian patent 387,792 and the equivalent t7.S. patents 4,246,221 and 4,416,698. A solution of cellulose in NMMO ~NNMO r t~-Methylmorpholine-N-oxide) and water is formed. The stretching ie effected with a stretching ratio of at least 3:1.
The drawback of this process is the poor flexibility avai~.able for a7.tering characteristics of the shaped body which is produced. A minimum spanning-stre~tahing ratio is necessary to provide aorx~esponding textile characteristics of the spun filament.
rn practice, only a limited range of textile fiber 25 characteristics can be produced and the fiber products by and large have a rather low average toughness, defined as the product of the Fiber tenacity arid the fiber elongation at break.
7856-~MR 2D59fl42 A further drawback is that so-called velocity res~anance, relating the withdrawal velocity and the orifice emergen~~e velocity, leads to fluctuation in fiber diameter, the latter growing with spinning/stretching ratio (see Navard, ~taudin, "Spinning of a Cellulose N-Methylmorpholine-N~-oxide solution", Polymer Process engineering, 3(3), 291 (1985)).
Finally, we may mention the disadvantage that the shape is imparted to the bod~r t~raatically only in the air gap. A change in the shape subsequently can only be accomplished with difficulty. As a result, the band width of the products which can be potentially made by the process is greatly limited. It is also desirable to be able to influence the product characteristics after aaagulation and, indeed, to provide a process fox fabricating shaped products from cellulosia solutions, which will have significant fl~xibility.
l, Obiects of t~~ Invention It is, therefore, the principal abject of the present invention to provide a pxoc~ass for producing shaped objects of cellulosic material by a process involving the forcing of the solution from a shaping orifice via an air gap into a coagulating 2D bath, whereby these drawbacks can be avoided.
Another object op this invention is to provide an improved method which will have increased versatility with respect to th~
range of properties of the products which are produced and which will facilitate the reproducibility of the process.
25 Another object of the invention is simply to avoid the drawbacks of earlier methods as described.
7856-MR 20~904~
~ummarv of thwgntion These objects and others which will become apparent hereinafter are attained, in accordance with the invention, which provides that the ratio of the withdrawal velocity to the orifice emergence velocity is at most l, and that the shaped body which is produced is stretched only after the coagulation.
The reference to stretching here is intended to inca.ude deep drawing, i.e. any process in which the shaped body is extended in any dimension.
More particularly, the method of the present invention can comprise the steps of:
(a) extruding a cellulosic solution capable of coagulation in a coagulation bath through an orifice to shape a stream of the solution;
(b) passing the stream of tha solution acxoss an air gap into the coagulation bath, thereby coagulating the solution and forming a continuous shaped body therefromt (c) controlling a withdraw2tl velocity at whioh the body is withdrawn from the coagulation bath and an orifice-emexgenc~
velocity at which the body emerges from the orifice eo that a ratio of the withdrawal velocity to the orifica-emergence ve~looity is at most 1: and (d) thereafter stretching the continuous shaped body, whereby the continuous shaped body composed of coagulated cellulose ig stretched only after the body has been withdrawn Pram the bath.
The withdrawal velocity a~ the body according to the inven-Lion is generally smallex than the orifice emergence velocity of the mass which i.s spun or is at most equaX to the orifice emergence velocity so that there is no stretching in the air gap and, preferably, na stxetching at any point prior to emergenc~a of the body from the coagulation bath. The cellulose until and during coagulation ire the coagulatiar bath, therefore, remains in a relatively nonoriented stated.
It has been found that it is highly advantageous to minimize the orientation before or during the coagulation and the greater the extent to which the orientation prior to or during coagulation is reduced, the greater is the possibility of influencing the characteristics o! the product, a.g. during the later orientation step. with slight orientation, the coagulated or precipitated cellulose has an elasticity which resembl~s that of rubber. This cellulo:e can then be stretched or deep drawn to impart to it they dee~ired characteristics; thereby thm flexibility with r~spect to the 13 property of the product is achieved.
According to a lectors o! this i»vention, they pxoduct is stretched in air or in water and can be a fiber or ~ilm or sheet.
Best results are obtained when the product is spun from a cellulose solution in NMMO and water and they coagulating bath contains t~rr~to a»d water.
A further advantage o~ the method o! thisc invention is that, since thm stretching does not occur in thd air gap, this air gap can be made relatively short. Therefore, even in cases when the spinneret has a high hole density there is little danger that neighboring ;fibers or filaments will adhere togeth~r. ~ince large-scale production requires a maximum hole density, the short air gap which promotes hale density has been found to be highly desirable in modern pxoductian techniques.
ar~.ef' ~escril~Qn, a the Ipraw nar The above and other ob~eats, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing, the sole FTGtJR~ of which is a flow diagram illustrating the principles of the present invention.
speciE~ES sGri,ptiorl =n the drawing, we have shown an apparatus camprising a pump 1 supplying a spinning solution of cellulose, NI~IO and water, to an lp inlet 11 of a spinneret 10 having a multiplicity of discharge orifices, one of which is shown to emit a stream x2 of the solution through an air gap 13. Instead of a spinneret, an extrusion die of the wide orifice type can be used to extrude the solution in the chaps o! a sheet, if desired.
Atter passing through the air gap 13, the shaped stream 12 of the solution enters a bath of a precipitating or coagulating ac~lution as represented $t 14 in a vassal 26, ~khe coagulating solutian being, e.g. a solution of NMMO in water.
Depleted precipitating solution can b~ drawn~off from the v,~ssel 26 by a pump 2? and recycled via a bath regeneration stage.
The bath regeneration stags 22 can also receive an NI~IO and water solution from a fiber washing stage, not shown, as represent~d at 21. Ths regeneratian can include evaporation of water to concentrate th~ NI~O which can be fed in part as represontad at 24 to a vessel in which the spinning solution is formed and in part, as represented at 25, back to the vessel 26.
., Water which is recovered can be fed at 23 to a fiber washing stage which may be coordinated with a stretching stage when the stretching is to take place under water.
The coagulated body 17 emerges from.t:he bath 14 and, after such emergence, is subjected to stretching in a stretching stage represented at 30. The stretching stage may include godet rolls 18, 19 driven at different speeds to Stretch the filament 31 between them. The st:retched filament 32 is supplied to a yarn take-up stage represented at 20.
A controller 33 regulates the pump 1, a motor 34 driving the roller 35 in the bath 14 around which the filament is guided, and the godet roll 18 so that the withdrawal speed or velocity of the filament 17 from the bath 14 is no greater than the speed with which the stream 12 emerges from the spinneret orifice, thereby excluding stretch in the air gap 13, in the bath 14 between the air gap and the roller 35 and in the bath between the roller 35 and emergence of the filament 17 from the bath and prior to its engagement by the godet roll 18. All stretch is confined between the rolls 18 and 19 and hence takes place after the filament 17 emerges from the bath.
The following examples will c:Larify the invention further.
Examples Example 1:
Production of a fiber with a .ratio of withdrawal velocity of orifice emergence velocity of less than 1.
(Comparative test.) A 13% cellu.losic NMMO solution (cellulose of the ViscokraftTM type marketed by the Firrn ICP, loo by weight water, 77o by weight NMMO, 0.1% oxalic acid as stabilizer) is forced through a spinneret having 100 holes each of a diameter of 130 micrometers.
_ g _ 20~~04~
The volumetric flow through the orifices of the spinneret was 16.5 g/min. The orifice emergence ve7.ocity for the filament stream was ltt.35 m/min. xhe 100 threads there passed through an 8 mm long air gap and then guided with a velocity of 6 m/min through a spin-ning bath of a path length of 15 cm. The temperature of the bath was 2°G and the bath consisted of aqueaus NMMe3 solut~.on with an NMM~
concentration of 5%.
The ratio of the withdrawal velocity to the orifice emergence velocity was therefore 0.58.
The resulting fiber had a tenacity of 11.8 cN/tex with an elongation of 77.5%. xhe value of the elongation was extremely high indicating that the cellulose strand had a relatively unordered structure.
Stretching of the fiber after coagulation in air.
In this test, Example 1 was followed but after leaving the spinning bath, i.e. after coagulation, was wound upon a first godet roll of a speed of 6 m per minute and the fiber bundle then fed to a second godet roll operating with a speed of 13 m per minute to effect a stretching between the rolls of 117%. Stretching in % is calculated as follows: S ~ ((EL ~- SL)/SL) x 100, where 8 ie the stretch in %, SL is th~ starting length, i.~. thd length prior to ~ctretchi»g, EL is the end length, i.e. the length subsequent to stretching. The resulting fibers had a tenacity of 22.4 cN/tex with an elongation of 15.3%.
7$56-MR
example 3 Stretching of the fiber after coagulation in water.
The fiber was produced as in Example 1 and passed from the spinning bath at 6 m/mxn (ratio of withdrawal speed to orifice emergence speed : 0.58) and then passed through an 89 cm long stretching bath aF water at a temperature pf 77°C. The godet rolls were immersed in the water of the stretching bath and the second godet rail wag driven at two different peripheral speeds y. The resulting fibers had the following characteristics.
v Stretching Titer Tenacity Elongation m/min S % dtex (Conditioned) (Conditioned) a~llte~ %
14 133 32.4 19.7 17.5 21 250 10.3 22.3 9.2 E~D~e Production of a fiber with a ratio of withdrawal velocity to orifice emergence velocity of greater than 1 (comparativ~ test).
A 13% ceilulosia NI~tO solution of the same typ~ as in Exampie 1 wag forced through a spinneret with 100 holes each having a 24 diameter of 70 micrometers. The volumetric flow was 5.1 g/min Corresponding to an orifice emergence velocity of 11.1 m/min. The withdrawal velocity at tha first godet roll was 33.3 m/min, i.e. the ratio of withdrawal velocity to orifice discharge velocity was 3.0:1. The fibers were passed through the spinning bath at the veloc~.ty of the first godet roll and the spinning bath had a temperature of 33°C and an Nt~to concentration of l0%.
The subsequent stretching bath had a temperature of 79°C and an NMMO concentration of: 90. The second godet roll downstream of the stretching bath had a withdrawal velocity of 46.9 m/min. The stretch amounted to 410. The textile characteristics of the resulting fibers were:
Titer: 3.5 dtex Tenacity (conditioned): 25 cN/tex Elongation (conditioned): 8.80 With a ratio of the withdrawal velocity to the orifice emergence velocity in excess; of l, the fibers remained stretchable not to the degree found with the systems of Examples 2-4.
Example 5:
Production of a foil.
A 9% cellulosic NMMO solution (cellulose: buckey V5T"" of Procter & Gamble, 12% water, 79% NMMO, 0.1% oxalic acid stabilizer) is forced through a. slit-type orifice (gap width = 50 micrometers, length = 30 mm).
The rate of flow is 21.3 g/m.in corresponding to an orifice emergence velocity of 11.7 rrl/min. The extruded stream was passed through a 7 mm lor..g air gap and then in contact with a spinning bath over a length of 15 cm. The spinning bath had a temperature of 24°C and an NMMO
concentration of 200.
The film is drawn via a first pair of rollers with a velocity of 6 m/min. The ratio of withdrawal velocity to orifice velocity was thus 0.51. In the same step, the foil is guided through an 80 cm lone stretching bath (temperature: 90°C; NMMO concentration: 200) and engaged by a second pair of rollers, operating with a peripheral speed of 11 m/min.
20~~042 The stretching amounted to 83%. The eharacteristiGS of the washed and dried fol7. were:
thickness: 10 micrometers;
strength: 200 N/mm2;
elongatir~n : 6 . 5% .
Example production of a shaped body.
A foil is produced as in Example 5 but snot stretched, i.e.
after the first tall, the foil is removed. In ~Ghe unstretched state it i$ deep drawn with a g~.ass rod through 3 mm, washed arid dried tc~
a stable shaped body.
MET~iUD OF PROD~(TCZNG SI~APED CEL~JLOSTC HO~T~:S
SPECII~xCAT~ON
Kiel ~f the)Enventi_on Our pxesent invention relates to a method of producing shaped cellulosic bodies in which a cellulosic amine oxide solution is extruded from a shaping orifice, e.g. a spinneret nozzle or a shaping die, and is passed into a coagulating or precipitating bath from which the Shaped object is withdrawn. Typical Shaped objects within the purview of the present invention are filaments or fibers lp and sheets or films.
~_Se.~~.~~L~~ ~! ~h~ nVA X11 =t is known to produce high polymer fibers with good fiber and film characteristics when, within the elongated body which is fabricated, a fiber structure is generated (see the Ullmann Encyclo-lg pedia, 5th Edition, Volume A10, page 456). Zt is desirable and, indeed, necessary to align micro-oriented regions, such as fibrides, in the fiber along the fiber axis. The alignment or orientation can be effBCted by various fabrication techniques and can dapend upon the physical or physical-chemical processes to which the fiber or film is subjected. xn many cases, this orientation can be effected by a stretching.
7856wMR
The process steps and the conditions in which and under which this stretching is caxried out has an impact upon the fiber properties whzch are produced, zn melt spinning, the fiY~ers are stretched in a hot plastic state while the molecules are mobile.
Soluble polymers can be wet spun or dry spun. zn dry spinning, the stretching is effected while the solvent is removed or is evaporated. Extruded Fibers which axe coagulated in a precipitating or coagulating bath are commonly stretched during the coagulation.
Processes of these types are well known and are widely described. zn all of these cases, however, it is important that the transition From the liquid state (independently of whethex this state is a melt state or a solution state) to the solid state be so e!leoted that during the filament formation, an orienxation of the polymer chains or polymer chain packetra, referred to as gibride~s, librilts or the like, is brought about.
xo inhibit the flash evaporation of a solvent from a filament during dry spinning, there are numerous possibilities. However, the problem of extremely rapid coagulation o! polymers during wet spin-ning, as is the case with the spinning a! csilulosio amin~ oxide solutions, has been solved heretoEars only by a combination of dry spinning and wet spinning.
zt is, therefore, known to pass solutions of polymers into the coagulation medium via an air gap. In EP~A~2~~ 672, in the production of aramid fibers which are brought into a noncoagulating medium via an air gap, stretched and then subjected to coagulation, there is a combination of features of both dry and wet rpinning.
20~904~
In the East German patent 218 ~.~7., the spinning l:rom cellulose zn amine oxides is effected via an air gap and precautions must be taken to prevent adhesion of the objects produced. U.S.
patent 4,501,886 describes the spinning of a solution of cellulose triacetate using an air gap. In U.S. patent 3,414,645, 'the production of aromatic polyamide objects from solution is effected in a dry-wet spinning process.
In all of these processes, an orientation is effected in the air gap if only because the downwardly emerging solution from the la orifice is at least stretched by the gravitational force on the solution. The orientation effected by the gravitational action can be increased when the extruder velocity, they velaaity at which the solution emerges from the orifice, and the withdrawal speed of the fiber passing through the coagulating bath are so adjusted that 15 further stretching occurs. A process of this latter typ~ is described in Austrian patent 387,792 and the equivalent t7.S. patents 4,246,221 and 4,416,698. A solution of cellulose in NMMO ~NNMO r t~-Methylmorpholine-N-oxide) and water is formed. The stretching ie effected with a stretching ratio of at least 3:1.
The drawback of this process is the poor flexibility avai~.able for a7.tering characteristics of the shaped body which is produced. A minimum spanning-stre~tahing ratio is necessary to provide aorx~esponding textile characteristics of the spun filament.
rn practice, only a limited range of textile fiber 25 characteristics can be produced and the fiber products by and large have a rather low average toughness, defined as the product of the Fiber tenacity arid the fiber elongation at break.
7856-~MR 2D59fl42 A further drawback is that so-called velocity res~anance, relating the withdrawal velocity and the orifice emergen~~e velocity, leads to fluctuation in fiber diameter, the latter growing with spinning/stretching ratio (see Navard, ~taudin, "Spinning of a Cellulose N-Methylmorpholine-N~-oxide solution", Polymer Process engineering, 3(3), 291 (1985)).
Finally, we may mention the disadvantage that the shape is imparted to the bod~r t~raatically only in the air gap. A change in the shape subsequently can only be accomplished with difficulty. As a result, the band width of the products which can be potentially made by the process is greatly limited. It is also desirable to be able to influence the product characteristics after aaagulation and, indeed, to provide a process fox fabricating shaped products from cellulosia solutions, which will have significant fl~xibility.
l, Obiects of t~~ Invention It is, therefore, the principal abject of the present invention to provide a pxoc~ass for producing shaped objects of cellulosic material by a process involving the forcing of the solution from a shaping orifice via an air gap into a coagulating 2D bath, whereby these drawbacks can be avoided.
Another object op this invention is to provide an improved method which will have increased versatility with respect to th~
range of properties of the products which are produced and which will facilitate the reproducibility of the process.
25 Another object of the invention is simply to avoid the drawbacks of earlier methods as described.
7856-MR 20~904~
~ummarv of thwgntion These objects and others which will become apparent hereinafter are attained, in accordance with the invention, which provides that the ratio of the withdrawal velocity to the orifice emergence velocity is at most l, and that the shaped body which is produced is stretched only after the coagulation.
The reference to stretching here is intended to inca.ude deep drawing, i.e. any process in which the shaped body is extended in any dimension.
More particularly, the method of the present invention can comprise the steps of:
(a) extruding a cellulosic solution capable of coagulation in a coagulation bath through an orifice to shape a stream of the solution;
(b) passing the stream of tha solution acxoss an air gap into the coagulation bath, thereby coagulating the solution and forming a continuous shaped body therefromt (c) controlling a withdraw2tl velocity at whioh the body is withdrawn from the coagulation bath and an orifice-emexgenc~
velocity at which the body emerges from the orifice eo that a ratio of the withdrawal velocity to the orifica-emergence ve~looity is at most 1: and (d) thereafter stretching the continuous shaped body, whereby the continuous shaped body composed of coagulated cellulose ig stretched only after the body has been withdrawn Pram the bath.
The withdrawal velocity a~ the body according to the inven-Lion is generally smallex than the orifice emergence velocity of the mass which i.s spun or is at most equaX to the orifice emergence velocity so that there is no stretching in the air gap and, preferably, na stxetching at any point prior to emergenc~a of the body from the coagulation bath. The cellulose until and during coagulation ire the coagulatiar bath, therefore, remains in a relatively nonoriented stated.
It has been found that it is highly advantageous to minimize the orientation before or during the coagulation and the greater the extent to which the orientation prior to or during coagulation is reduced, the greater is the possibility of influencing the characteristics o! the product, a.g. during the later orientation step. with slight orientation, the coagulated or precipitated cellulose has an elasticity which resembl~s that of rubber. This cellulo:e can then be stretched or deep drawn to impart to it they dee~ired characteristics; thereby thm flexibility with r~spect to the 13 property of the product is achieved.
According to a lectors o! this i»vention, they pxoduct is stretched in air or in water and can be a fiber or ~ilm or sheet.
Best results are obtained when the product is spun from a cellulose solution in NMMO and water and they coagulating bath contains t~rr~to a»d water.
A further advantage o~ the method o! thisc invention is that, since thm stretching does not occur in thd air gap, this air gap can be made relatively short. Therefore, even in cases when the spinneret has a high hole density there is little danger that neighboring ;fibers or filaments will adhere togeth~r. ~ince large-scale production requires a maximum hole density, the short air gap which promotes hale density has been found to be highly desirable in modern pxoductian techniques.
ar~.ef' ~escril~Qn, a the Ipraw nar The above and other ob~eats, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing, the sole FTGtJR~ of which is a flow diagram illustrating the principles of the present invention.
speciE~ES sGri,ptiorl =n the drawing, we have shown an apparatus camprising a pump 1 supplying a spinning solution of cellulose, NI~IO and water, to an lp inlet 11 of a spinneret 10 having a multiplicity of discharge orifices, one of which is shown to emit a stream x2 of the solution through an air gap 13. Instead of a spinneret, an extrusion die of the wide orifice type can be used to extrude the solution in the chaps o! a sheet, if desired.
Atter passing through the air gap 13, the shaped stream 12 of the solution enters a bath of a precipitating or coagulating ac~lution as represented $t 14 in a vassal 26, ~khe coagulating solutian being, e.g. a solution of NMMO in water.
Depleted precipitating solution can b~ drawn~off from the v,~ssel 26 by a pump 2? and recycled via a bath regeneration stage.
The bath regeneration stags 22 can also receive an NI~IO and water solution from a fiber washing stage, not shown, as represent~d at 21. Ths regeneratian can include evaporation of water to concentrate th~ NI~O which can be fed in part as represontad at 24 to a vessel in which the spinning solution is formed and in part, as represented at 25, back to the vessel 26.
., Water which is recovered can be fed at 23 to a fiber washing stage which may be coordinated with a stretching stage when the stretching is to take place under water.
The coagulated body 17 emerges from.t:he bath 14 and, after such emergence, is subjected to stretching in a stretching stage represented at 30. The stretching stage may include godet rolls 18, 19 driven at different speeds to Stretch the filament 31 between them. The st:retched filament 32 is supplied to a yarn take-up stage represented at 20.
A controller 33 regulates the pump 1, a motor 34 driving the roller 35 in the bath 14 around which the filament is guided, and the godet roll 18 so that the withdrawal speed or velocity of the filament 17 from the bath 14 is no greater than the speed with which the stream 12 emerges from the spinneret orifice, thereby excluding stretch in the air gap 13, in the bath 14 between the air gap and the roller 35 and in the bath between the roller 35 and emergence of the filament 17 from the bath and prior to its engagement by the godet roll 18. All stretch is confined between the rolls 18 and 19 and hence takes place after the filament 17 emerges from the bath.
The following examples will c:Larify the invention further.
Examples Example 1:
Production of a fiber with a .ratio of withdrawal velocity of orifice emergence velocity of less than 1.
(Comparative test.) A 13% cellu.losic NMMO solution (cellulose of the ViscokraftTM type marketed by the Firrn ICP, loo by weight water, 77o by weight NMMO, 0.1% oxalic acid as stabilizer) is forced through a spinneret having 100 holes each of a diameter of 130 micrometers.
_ g _ 20~~04~
The volumetric flow through the orifices of the spinneret was 16.5 g/min. The orifice emergence ve7.ocity for the filament stream was ltt.35 m/min. xhe 100 threads there passed through an 8 mm long air gap and then guided with a velocity of 6 m/min through a spin-ning bath of a path length of 15 cm. The temperature of the bath was 2°G and the bath consisted of aqueaus NMMe3 solut~.on with an NMM~
concentration of 5%.
The ratio of the withdrawal velocity to the orifice emergence velocity was therefore 0.58.
The resulting fiber had a tenacity of 11.8 cN/tex with an elongation of 77.5%. xhe value of the elongation was extremely high indicating that the cellulose strand had a relatively unordered structure.
Stretching of the fiber after coagulation in air.
In this test, Example 1 was followed but after leaving the spinning bath, i.e. after coagulation, was wound upon a first godet roll of a speed of 6 m per minute and the fiber bundle then fed to a second godet roll operating with a speed of 13 m per minute to effect a stretching between the rolls of 117%. Stretching in % is calculated as follows: S ~ ((EL ~- SL)/SL) x 100, where 8 ie the stretch in %, SL is th~ starting length, i.~. thd length prior to ~ctretchi»g, EL is the end length, i.e. the length subsequent to stretching. The resulting fibers had a tenacity of 22.4 cN/tex with an elongation of 15.3%.
7$56-MR
example 3 Stretching of the fiber after coagulation in water.
The fiber was produced as in Example 1 and passed from the spinning bath at 6 m/mxn (ratio of withdrawal speed to orifice emergence speed : 0.58) and then passed through an 89 cm long stretching bath aF water at a temperature pf 77°C. The godet rolls were immersed in the water of the stretching bath and the second godet rail wag driven at two different peripheral speeds y. The resulting fibers had the following characteristics.
v Stretching Titer Tenacity Elongation m/min S % dtex (Conditioned) (Conditioned) a~llte~ %
14 133 32.4 19.7 17.5 21 250 10.3 22.3 9.2 E~D~e Production of a fiber with a ratio of withdrawal velocity to orifice emergence velocity of greater than 1 (comparativ~ test).
A 13% ceilulosia NI~tO solution of the same typ~ as in Exampie 1 wag forced through a spinneret with 100 holes each having a 24 diameter of 70 micrometers. The volumetric flow was 5.1 g/min Corresponding to an orifice emergence velocity of 11.1 m/min. The withdrawal velocity at tha first godet roll was 33.3 m/min, i.e. the ratio of withdrawal velocity to orifice discharge velocity was 3.0:1. The fibers were passed through the spinning bath at the veloc~.ty of the first godet roll and the spinning bath had a temperature of 33°C and an Nt~to concentration of l0%.
The subsequent stretching bath had a temperature of 79°C and an NMMO concentration of: 90. The second godet roll downstream of the stretching bath had a withdrawal velocity of 46.9 m/min. The stretch amounted to 410. The textile characteristics of the resulting fibers were:
Titer: 3.5 dtex Tenacity (conditioned): 25 cN/tex Elongation (conditioned): 8.80 With a ratio of the withdrawal velocity to the orifice emergence velocity in excess; of l, the fibers remained stretchable not to the degree found with the systems of Examples 2-4.
Example 5:
Production of a foil.
A 9% cellulosic NMMO solution (cellulose: buckey V5T"" of Procter & Gamble, 12% water, 79% NMMO, 0.1% oxalic acid stabilizer) is forced through a. slit-type orifice (gap width = 50 micrometers, length = 30 mm).
The rate of flow is 21.3 g/m.in corresponding to an orifice emergence velocity of 11.7 rrl/min. The extruded stream was passed through a 7 mm lor..g air gap and then in contact with a spinning bath over a length of 15 cm. The spinning bath had a temperature of 24°C and an NMMO
concentration of 200.
The film is drawn via a first pair of rollers with a velocity of 6 m/min. The ratio of withdrawal velocity to orifice velocity was thus 0.51. In the same step, the foil is guided through an 80 cm lone stretching bath (temperature: 90°C; NMMO concentration: 200) and engaged by a second pair of rollers, operating with a peripheral speed of 11 m/min.
20~~042 The stretching amounted to 83%. The eharacteristiGS of the washed and dried fol7. were:
thickness: 10 micrometers;
strength: 200 N/mm2;
elongatir~n : 6 . 5% .
Example production of a shaped body.
A foil is produced as in Example 5 but snot stretched, i.e.
after the first tall, the foil is removed. In ~Ghe unstretched state it i$ deep drawn with a g~.ass rod through 3 mm, washed arid dried tc~
a stable shaped body.
Claims (8)
1. A method of making a cellulosic shaped body, comprising the steps of:
(a) extruding a cellulosic solution capable of coagulation in a coagulation bath through an orifice to shape a stream of said solution;
(b) passing said stream of said solution across an air gap into said coagulation bath, thereby coagulating said solution and forming a continuous shaped body therefrom;
(c) controlling a withdrawal velocity at which said body is withdrawn from said coagulation bath and an orifice--emergence velocity at which said body emerges from said orifice so that a ratio of said withdrawal velocity to said orifice-emergence velocity is at most 1; and (d) thereafter stretching said continuous shaped body, whereby said continuous shaped body composed of coagulated cellulose is stretched only after said body has been withdrawn from said bath.
(a) extruding a cellulosic solution capable of coagulation in a coagulation bath through an orifice to shape a stream of said solution;
(b) passing said stream of said solution across an air gap into said coagulation bath, thereby coagulating said solution and forming a continuous shaped body therefrom;
(c) controlling a withdrawal velocity at which said body is withdrawn from said coagulation bath and an orifice--emergence velocity at which said body emerges from said orifice so that a ratio of said withdrawal velocity to said orifice-emergence velocity is at most 1; and (d) thereafter stretching said continuous shaped body, whereby said continuous shaped body composed of coagulated cellulose is stretched only after said body has been withdrawn from said bath.
2. The method defined in claim 1 wherein said velocities are controlled so that stretching of said stream in said air gap is precluded.
3. The method defined in claim 2 wherein said solution is a solution of cellulose in N-methylmorpholine-N-oxide and water.
4. The method defined in claim wherein said coagulation bath is a bath of N-methylmorpholine-N-oxide and water.
5. The method defined in claim 4 wherein said body is a fiber.
6. The method defined in claim 4 wherein said body is a sheet.
7. The method defined is claim 1 wherein said body is stretched in step (d) in air.
8. The method defined in claim 4 wherein said body is stretched in step (d) in water.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT31/91 | 1991-01-09 | ||
| AT0003191A AT395862B (en) | 1991-01-09 | 1991-01-09 | METHOD FOR PRODUCING A CELLULOSIC MOLDED BODY |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2059042A1 CA2059042A1 (en) | 1992-07-10 |
| CA2059042C true CA2059042C (en) | 2002-05-14 |
Family
ID=3479697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002059042A Expired - Fee Related CA2059042C (en) | 1991-01-09 | 1992-01-08 | Method of producing shaped cellulosic bodies |
Country Status (28)
| Country | Link |
|---|---|
| EP (1) | EP0494851B1 (en) |
| JP (1) | JP3072442B2 (en) |
| KR (1) | KR100210294B1 (en) |
| AT (1) | AT395862B (en) |
| AU (1) | AU648618B2 (en) |
| BG (1) | BG60110B2 (en) |
| BR (1) | BR9200035A (en) |
| CA (1) | CA2059042C (en) |
| CZ (1) | CZ282935B6 (en) |
| DE (1) | DE59208903D1 (en) |
| ES (1) | ES2109333T3 (en) |
| FI (1) | FI102391B (en) |
| GR (1) | GR3025632T3 (en) |
| HU (1) | HU212701B (en) |
| IE (1) | IE920053A1 (en) |
| IL (1) | IL100619A0 (en) |
| MA (1) | MA22373A1 (en) |
| MX (1) | MX9200098A (en) |
| NO (1) | NO303738B1 (en) |
| PL (1) | PL169424B1 (en) |
| PT (1) | PT99990A (en) |
| RO (1) | RO107703B1 (en) |
| RU (1) | RU2061115C1 (en) |
| SK (1) | SK280035B6 (en) |
| TR (1) | TR25874A (en) |
| YU (1) | YU47786B (en) |
| ZA (1) | ZA9110159B (en) |
| ZW (1) | ZW192A1 (en) |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5451364A (en) * | 1992-01-17 | 1995-09-19 | Viskase Corporation | Cellulose food casing manufacturing method |
| USH1592H (en) * | 1992-01-17 | 1996-09-03 | Viskase Corporation | Cellulosic food casing |
| ATA53792A (en) * | 1992-03-17 | 1995-02-15 | Chemiefaser Lenzing Ag | METHOD FOR PRODUCING CELLULOSIC MOLDED BODIES, DEVICE FOR IMPLEMENTING THE METHOD AND USE OF A SPINNING DEVICE |
| DE4308524C1 (en) * | 1992-06-16 | 1994-09-22 | Thueringisches Inst Textil | Process for the production of cellulose fibers and filaments by the dry-wet extrusion process |
| AT401271B (en) * | 1993-07-08 | 1996-07-25 | Chemiefaser Lenzing Ag | METHOD FOR PRODUCING CELLULOSE FIBERS |
| DE4421482C2 (en) * | 1994-06-20 | 1997-04-03 | Fraunhofer Ges Forschung | Process for producing oriented cellulose films and the films produced by this process and their use |
| US5603884A (en) * | 1994-11-18 | 1997-02-18 | Viskase Corporation | Reinforced cellulosic film |
| WO1996017118A1 (en) * | 1994-12-02 | 1996-06-06 | Akzo Nobel N.V. | Method of producing shaped cellulose bodies, and yarn made of cellulose filaments |
| US5658525A (en) * | 1995-08-04 | 1997-08-19 | Viskase Corporation | Cellulose food casing manufacturing method |
| TW389799B (en) * | 1995-08-29 | 2000-05-11 | Asahi Chemical Ind | Cellulose multifilament yarn and fabric made thereof |
| DE19541824A1 (en) * | 1995-11-10 | 1997-05-15 | Thueringisches Inst Textil | Process and apparatus for producing cellulose filament yarns |
| AT404032B (en) * | 1996-03-04 | 1998-07-27 | Chemiefaser Lenzing Ag | METHOD FOR PRODUCING CELLULOSIC FIBERS |
| GB9605504D0 (en) * | 1996-03-15 | 1996-05-15 | Courtaulds Plc | Manufacture of elongate members |
| ES2232942T3 (en) * | 1997-04-25 | 2005-06-01 | Lenzing Aktiengesellschaft | PROCEDURE FOR THE MANUFACTURE OF MOLDED BODIES OF CELLULOSE. |
| AT404731B (en) | 1997-04-25 | 1999-02-25 | Chemiefaser Lenzing Ag | METHOD FOR PRODUCING CELLULOSIC FLAT FILMS AND THEIR USE |
| US6165401A (en) * | 1997-04-25 | 2000-12-26 | Lenzing Aktiengesellschaft | Process for the production of cellulosic moulded bodies |
| DE10200405A1 (en) | 2002-01-08 | 2002-08-01 | Zimmer Ag | Cooling blowing spinning apparatus and process |
| DE10204381A1 (en) | 2002-01-28 | 2003-08-07 | Zimmer Ag | Ergonomic spinning system |
| DE10206089A1 (en) | 2002-02-13 | 2002-08-14 | Zimmer Ag | bursting |
| DE10314878A1 (en) * | 2003-04-01 | 2004-10-28 | Zimmer Ag | Method and device for producing post-stretched cellulose filaments |
| AT6807U1 (en) * | 2004-01-13 | 2004-04-26 | Chemiefaser Lenzing Ag | CELLULOSIC FIBER OF THE LYOCELL GENERATION |
| DE102004024030A1 (en) | 2004-05-13 | 2005-12-08 | Zimmer Ag | Lyocell process with polymerization-degree-dependent adjustment of the processing time |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB796544A (en) * | 1954-10-13 | 1958-06-11 | British Celanese | Improvements in the manufacture of artificial filaments and like products |
| US3767756A (en) * | 1972-06-30 | 1973-10-23 | Du Pont | Dry jet wet spinning process |
| US4416698A (en) * | 1977-07-26 | 1983-11-22 | Akzona Incorporated | Shaped cellulose article prepared from a solution containing cellulose dissolved in a tertiary amine N-oxide solvent and a process for making the article |
| US4464323A (en) * | 1982-08-09 | 1984-08-07 | E. I. Du Pont De Nemours And Company | Process for preparing high strength cellulosic fibers |
| FR2617511B1 (en) * | 1987-07-01 | 1989-12-15 | Inst Textile De France | PROCESS FOR THE PREPARATION OF A CELLULOSE SPINNING SOLUTION IN THE PRESENCE OF TERTIARY AMINE OXIDE AND ADDITIVE |
-
1991
- 1991-01-09 AT AT0003191A patent/AT395862B/en not_active IP Right Cessation
- 1991-12-17 AU AU89798/91A patent/AU648618B2/en not_active Ceased
- 1991-12-19 MA MA22657A patent/MA22373A1/en unknown
- 1991-12-23 YU YU197691A patent/YU47786B/en unknown
- 1991-12-27 ZA ZA9110159A patent/ZA9110159B/en unknown
-
1992
- 1992-01-06 ZW ZW1/92A patent/ZW192A1/en unknown
- 1992-01-06 KR KR1019920000040A patent/KR100210294B1/en not_active IP Right Cessation
- 1992-01-06 BG BG095726A patent/BG60110B2/en unknown
- 1992-01-06 RO RO149066A patent/RO107703B1/en unknown
- 1992-01-08 HU HU9200066A patent/HU212701B/en not_active IP Right Cessation
- 1992-01-08 RU SU925010549A patent/RU2061115C1/en not_active IP Right Cessation
- 1992-01-08 FI FI920071A patent/FI102391B/en not_active IP Right Cessation
- 1992-01-08 PL PL92293116A patent/PL169424B1/en unknown
- 1992-01-08 JP JP4001348A patent/JP3072442B2/en not_active Expired - Lifetime
- 1992-01-08 NO NO920105A patent/NO303738B1/en not_active IP Right Cessation
- 1992-01-08 CZ CS9245A patent/CZ282935B6/en unknown
- 1992-01-08 PT PT99990A patent/PT99990A/en not_active Application Discontinuation
- 1992-01-08 CA CA002059042A patent/CA2059042C/en not_active Expired - Fee Related
- 1992-01-08 IE IE005392A patent/IE920053A1/en not_active IP Right Cessation
- 1992-01-08 BR BR929200035A patent/BR9200035A/en not_active IP Right Cessation
- 1992-01-08 SK SK45-92A patent/SK280035B6/en unknown
- 1992-01-09 ES ES92890003T patent/ES2109333T3/en not_active Expired - Lifetime
- 1992-01-09 DE DE59208903T patent/DE59208903D1/en not_active Expired - Lifetime
- 1992-01-09 EP EP92890003A patent/EP0494851B1/en not_active Expired - Lifetime
- 1992-01-09 MX MX9200098A patent/MX9200098A/en not_active IP Right Cessation
- 1992-01-09 IL IL100619A patent/IL100619A0/en unknown
- 1992-01-09 TR TR92/0017A patent/TR25874A/en unknown
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