CA2255638A1 - Device and method for producing cellulose tubular films - Google Patents
Device and method for producing cellulose tubular films Download PDFInfo
- Publication number
- CA2255638A1 CA2255638A1 CA002255638A CA2255638A CA2255638A1 CA 2255638 A1 CA2255638 A1 CA 2255638A1 CA 002255638 A CA002255638 A CA 002255638A CA 2255638 A CA2255638 A CA 2255638A CA 2255638 A1 CA2255638 A1 CA 2255638A1
- Authority
- CA
- Canada
- Prior art keywords
- solution
- precipitant
- cellulose
- spacer
- transport direction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 229920002678 cellulose Polymers 0.000 title claims abstract description 30
- 239000001913 cellulose Substances 0.000 title claims abstract description 30
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 238000001125 extrusion Methods 0.000 claims abstract description 36
- 150000003512 tertiary amines Chemical class 0.000 claims abstract description 13
- 230000001376 precipitating effect Effects 0.000 claims abstract description 7
- 238000001556 precipitation Methods 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 21
- 125000006850 spacer group Chemical group 0.000 claims description 21
- 230000007423 decrease Effects 0.000 claims description 4
- LFTLOKWAGJYHHR-UHFFFAOYSA-N N-methylmorpholine N-oxide Chemical compound CN1(=O)CCOCC1 LFTLOKWAGJYHHR-UHFFFAOYSA-N 0.000 claims description 3
- 230000002706 hydrostatic effect Effects 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 abstract 5
- 239000000243 solution Substances 0.000 description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 150000001412 amines Chemical class 0.000 description 6
- 238000009987 spinning Methods 0.000 description 3
- 239000000835 fiber Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 229920000875 Dissolving pulp Polymers 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000000502 dialysis Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000010096 film blowing Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/28—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of blown tubular films, e.g. by inflation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
- B29C48/10—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
- B29C48/919—Thermal treatment of the stream of extruded material, e.g. cooling using a bath, e.g. extruding into an open bath to coagulate or cool the material
-
- 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
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/16—Cooling
- B29C2035/1616—Cooling using liquids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
- B29C48/911—Cooling
- B29C48/9115—Cooling of hollow articles
- B29C48/912—Cooling of hollow articles of tubular films
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
-
- 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
Abstract
The invention concerns a device for producing cellulose tubular films by extruding a solution of cellulose in an aqueous tertiary amine oxide into a precipitating agent located beneath the device which is comprised of an extrusion nozzle with an essentially annular extrusion gap; a supply line for precipitating agent and a drain for said precipitating agent is provided in the interior of the ring formed by the extrusion slot; this device is characterized in that the supply line (3) for the precipitating agent ends below the drain (4) for said precipitating agent.
Description
CA 022~638 1998-11-19 ( ?~
Device ~n~l Process for Produci~g Cellulosic Tubular F;lm~
The present invention relates to a device for the production of cellulosic tubular films by extruding a solution of cellulose in an aqueous tertiary amine oxide into a precipitant present below the device, which device comprises an extrusion die having a substantially annular extrusion gap, wherein a supply duct for precipitant and a discharge duct for used precipitant are provided in the interior of the ring formed by the extrusion gap. The present invention also relates to a process for producing cellulosic tubular films.
From U.S. Patent No. 2,179,181 it is known that tertiary amine oxides are capable of dissolving cellulose and that cellulosic molded bodies such as fibers may be obtained from such solutions by precipitation. A process for producing solutions of this kind is known, for instance, from EP-A - 0 356 419. According to that publication, a suspension of cellulose in an aqueous tertiary amine oxide is initially prepared. The amine oxide contains up to 40 % by mass of water. The aqueous cellulose suspension is heated and water is drawn off under a pressure decrease until the cellulose is dissolved.
For the production of cellulose fibers it is known from DE-A - 28 44 163 to provide an air path or air gap between spinneret and precipitation bath in order to obtain a spinneret draft.
That spinneret draft is necessary, since stretching of the threads is rendered very difficult after a contact of the formed spinning solution with the aqueous precipitation bath. The fiber structure adjusted in the air gap is fixed in the precipitation bath.
A process for producing cellulosic threads is, furthermore, known from DE-A - 28 30 685, according to which a solution of cellulose in a tertiary amine oxide is molded to filaments in the hot state, the filaments are cooled with air and subsequently introduced into a precipitation bath in order to precipitate the dissolved cellulose. The surfaces of the as-spun threads, in addition, are wetted with water in order to reduce their tendency to adhere to neighboring threads.
A device for producing seamless tubular films is known from WO 93/13670. According to that known process, the cellulose solution is molded to a tube by an extrusion die having an annular extrusion gap, which tube is drawn over a cylindrical mandrel and introduced into a precipitation bath. In order that the extruded tube will not adhere to the surface of the mandrel, its surface is coated with a water film in a manner that the inner side of the tube coagulates and slides over the cylindrical mandrel. This has, however, the disadvantage that the water fed for wetting the surface of the mandrel can ascend as far as to the extrusion gap thereby wetting the die lip and causing the extrusion die to be cooled in addition to inducing undesired coagulations already during the extrusion procedure proper. This is undesired, CA 022~638 1998-11-19 because the cooled die cools the solution to be extruded, whose viscosity will thereby increase so as to render impossible a perfect extrusion to films having uniform thicknesses. Add to this that the known device is only cumbersome to reconvert if, for instance, films having different thickn~sses are to be produced.
From EP-A - 0 042 517 a process for producing a dialysis membrane of cellulose is known, in which membranes are produced from flat films or tubular films or hollow threads by means of applopliate dies.
From WO 95/35340 a blowing process for producing oriented cellulose films by spinning a cellulose solution in a plecipil~lion bath is known, in which the solution is extruded through a film blowing die and an external air gap downwardly into the precipitation bath. The degree of orientation may be increased by longitudinal and transverse stretching.
From DE-A - 195 15 137 a process for producing tubular films is known, according to which a cellulose solution at first is extruded to a tube, which tube on its way from the annular die outlet to the entry into the precipitation medium is stretched in the direction of extrusion and widened, i.e., extended at a ratio ranging between 1: 1 and 1: 10 by a gas pl es~ul e prevailing in the tube interior. By that extension, the tube is thus stretched transverse to the direction of extrusion.
A device of the initially defined kind, i.e., for producing cellulosic tubular films by extruding a solution of cellulose in a tertiary amine oxide into a precipitant present below the device, which device comprises an extrusion die having a subst~nt~ y annular extrusion gap, wherein a feed duct for pl~cipil~ll and a discharge duct for used precipitant are provided in the interior of the ring formed by the extrusion gap, may be taken from WO 95/07811. In that device, a spacer disc may be provided below the discharge duct in order to prevent the extruded tubular film from collapsing in the precipitation bath.
The prior art devices for the production of tubular films are complex in structure. It is, therefore, the object of the present invention to provide a device for the production of tubular films, which is of simpler construction.
The device according to the invention for producing cellulosic tubular films by extruding a solution of cellulose in a tertiary amine oxide into a precipitant present below the device, which device comprises an extrusion die having a substantially annular extrusion gap, wherein a supply duct for precipitant and a discharge duct for used precipitant are provided in the interior of the ring formed by the extrusion gap, is characterized in that the supply duct for the precipitant tt?lmin~tes below the discharge duct for the used precipitant.
CA 022~638 1998-11-19 It has been shown that in the device according to the invention the liquid level in the interior of the tube may be adjusted and, above all, kept constant in a simple manner. Furthermore, it has proved advantageous to the precipitating procedure? if the precipitant is allowed to stream opposite to the direction of extrusion, i.e., transport direction into the precipitation bath, in the interior of the tube. The present invention differs from the prior art also in this respect, since, as will be described below, fresh precipitant always gets into contact with film regions in which the cellulose is present in the precipitated state already to a high degree. On the other hand, the precipitant enriched most with amine oxide gets into contact with film regions in which the cellulose is present to a yet slightly plecipil~ted extent.
A preferred configuration of the device according to the invention is characterized in that a spacer is provided below the extrusion gap, which spacer preferably is designed to have a substantially circular periphery.
The cross sectional area of the spacer may be larger than the area formed by the ring of the extrusion gap. This enables stretching of the tubularly extruded solution transverse to the transport direction.
The cross sectional area of the spacer may, however, also be smaller than the area formed by the ring of the extrusion gap.
The spacer preferably is designed such that the size of the cross sectional area may be changed. This is feasible, for instance, with a disc, or a ring, including displaceable members in a manner analogous to an apertured diaphragm, in which the displaceable parts may slide on or within one another, thereby enabling the external diameter to be changed.
A change in the size of the cross sectional area may, furthermore, be reached in that the spacer is comprised of an elastic ring, for instance of rubber, to which air, water or the like may be fed. The diameter of the elastic ring is, thus, controllable via the medium contained in its interior. A variant of this embodiment consists in that no complete ring is used, but the inner side is comprised of a solid part of, e.g., steel or plastics and an elastic part is attached to the same. Another embodiment consists in a semi-shell, optionally comprised of segments, whose fixed point is displaceable, thereby ch~nging the external diameter (umbrella principle).
The invention also relates to a process for producing cellulosic tubular films, in which a solution of cellulose in a tertiary amine oxide is extruded through an extrusion die having a substantially annular extrusion gap, wherein the solution is molded in a tubular manner, which solution is transported into a precipitation bath and contacted with precipitant both on its irmer CA 022~638 1998-11-19 side and on its outer side, whereby the cellulose is precipitated and the tubular film is formed, which is characterized in that the precipitallt with which the tubularly molded solution is contacted on its inner side contains dissolved tertiary amine oxide whose concentration decreases in the transport direction of the tubularly molded solution.
In the process according to the invention, the tubularly molded solution may be stretched in the transport direction andlor transverse to the transport direction.
Stretching of the tubularly molded solution transverse to the transport direction may be effected by hydrostatic p,es~u,e or by gas pres~ule or by means of a spacer.
The tubular film molded by pleci~ila~ g the cellulose after transportation through the precipitation bath is dried, wherein the tubular film is preferably kept under tension in order to prevent shrinking.
The process according to the invention is particularly suitable for processing aqueous solutions of cellulose in aqueous N-methylmorpholine-N-oxide (NMMO).
A plef~lled configuration of the device according to the invention will be explained in more detail by way of the annexed drawing.
Fig. 1 schematically shows a cross section through the lower part of an extrusion device substantially comprising an annular die 1 having an annular extrusion gap 2, a supply duct 3 for fresh precipitant (water or an amine oxide/water mixture) and a discharge duct 4 for used precipitant.
The cellulose solution is pressed through the extrusion gap 2 via the annular spinning mass space 5, thereby extruding the cellulose solution in the form of a tubular film 6 into the air space present between the precipitation bath surface 7 and the lower side 8 of the annular die 1.
The tubularly extruded solution 6 is drawn off into the precipitation bath 7, in which it gets into contact with precipitant on its outer side, thereby causing the dissolved cellulose to coagulate and the amine oxide to be released into the precipitation bath. Precipitant is also in the interior of the tube 6 such that the cellulose coagulates also on its inner side. In doing so, amine oxide is released again.
In the Figure, the level 8 of the precipitant present in the interior of the tube 6 is on equal height with the precipitation bath 7. Precipitant may be introduced into the interior of the tube CA 022~638 1998-11-19 6 via the supply duct 3 and drawn off via the discharge duct 4. In this manner, the level 8 of the precipitant may be adjusted in the interior of the tube 6.
In the process according to the invention, the level 8 of the precipitant present in the interior of the tube 6 also may be adjusted to be higher or lower than the level of the precipitation bath 7. The composition of the precipitant in the interior of the tube 6 may differ from that of the precipitation bath.
The tubular film 6 is drawn off via deflection means 10 and thereby stretched in the transport direction, i.e., in the direction toward the precipitation bath 7.
The tubular film 6 is drawn over a spacer 9. That spacer 9 has the form of a circular disc firmly connected with the die 1 by means of rods 11. The spacer 9 comprises continuous bores 9a for mass transfer. The supply duct 3 passes through the spacer 9. The disc also may be replaced with a spacer ring.
The tube 6 is extended by the spacer 9, this corresponding to stretching transverse to the transport direction. It is evident that such stretching transverse to the transport direction increases with the size of the circular spacer.
By feeding fresh plecipitant via the supply duct 3 and discharging used, i.e. amine-oxide-cont~ining, precipitation bath via the discharge duct 4, which terrnin~tes above the supply duct 3, the concentration of amine oxide increases in the direction toward the level 8 or, in other words decreases in the transport direction of the tubular film 6.
On the end of the supply duct 3 there may also be provided baffle plates (not illustrated) in order to divert the liquid stream from the supply duct 3 upwardly in the direction of the level 8.
Stretching transverse to the transport direction may also be obtained by means of hydrostatic pres~u-e instead of the spacer. To this end, the level 8 of the precipitant within the tube 6 simply is adjusted to be higher than the level 7 of the precipitation bath. In doing so, extension is caused by the pressure of that part of the precipitant present in the interior of the tube 6, which is above the level 7.
Extension also may be obtained by means of gas pleS~ule, wherein the die 1 must, of course, be provided with a gas feed (not shown), by means of which the tubular film 6 is infl~te~l in the space provided between the lower side 8 of the die and the precipitation bath 7. The gas CA 022~638 1998-11-19 may also be replaced, which means that operation is effected at a gas excess. In that case, also a gas discharge duct (not illustrated), of course, is to be provided on the die.
Device ~n~l Process for Produci~g Cellulosic Tubular F;lm~
The present invention relates to a device for the production of cellulosic tubular films by extruding a solution of cellulose in an aqueous tertiary amine oxide into a precipitant present below the device, which device comprises an extrusion die having a substantially annular extrusion gap, wherein a supply duct for precipitant and a discharge duct for used precipitant are provided in the interior of the ring formed by the extrusion gap. The present invention also relates to a process for producing cellulosic tubular films.
From U.S. Patent No. 2,179,181 it is known that tertiary amine oxides are capable of dissolving cellulose and that cellulosic molded bodies such as fibers may be obtained from such solutions by precipitation. A process for producing solutions of this kind is known, for instance, from EP-A - 0 356 419. According to that publication, a suspension of cellulose in an aqueous tertiary amine oxide is initially prepared. The amine oxide contains up to 40 % by mass of water. The aqueous cellulose suspension is heated and water is drawn off under a pressure decrease until the cellulose is dissolved.
For the production of cellulose fibers it is known from DE-A - 28 44 163 to provide an air path or air gap between spinneret and precipitation bath in order to obtain a spinneret draft.
That spinneret draft is necessary, since stretching of the threads is rendered very difficult after a contact of the formed spinning solution with the aqueous precipitation bath. The fiber structure adjusted in the air gap is fixed in the precipitation bath.
A process for producing cellulosic threads is, furthermore, known from DE-A - 28 30 685, according to which a solution of cellulose in a tertiary amine oxide is molded to filaments in the hot state, the filaments are cooled with air and subsequently introduced into a precipitation bath in order to precipitate the dissolved cellulose. The surfaces of the as-spun threads, in addition, are wetted with water in order to reduce their tendency to adhere to neighboring threads.
A device for producing seamless tubular films is known from WO 93/13670. According to that known process, the cellulose solution is molded to a tube by an extrusion die having an annular extrusion gap, which tube is drawn over a cylindrical mandrel and introduced into a precipitation bath. In order that the extruded tube will not adhere to the surface of the mandrel, its surface is coated with a water film in a manner that the inner side of the tube coagulates and slides over the cylindrical mandrel. This has, however, the disadvantage that the water fed for wetting the surface of the mandrel can ascend as far as to the extrusion gap thereby wetting the die lip and causing the extrusion die to be cooled in addition to inducing undesired coagulations already during the extrusion procedure proper. This is undesired, CA 022~638 1998-11-19 because the cooled die cools the solution to be extruded, whose viscosity will thereby increase so as to render impossible a perfect extrusion to films having uniform thicknesses. Add to this that the known device is only cumbersome to reconvert if, for instance, films having different thickn~sses are to be produced.
From EP-A - 0 042 517 a process for producing a dialysis membrane of cellulose is known, in which membranes are produced from flat films or tubular films or hollow threads by means of applopliate dies.
From WO 95/35340 a blowing process for producing oriented cellulose films by spinning a cellulose solution in a plecipil~lion bath is known, in which the solution is extruded through a film blowing die and an external air gap downwardly into the precipitation bath. The degree of orientation may be increased by longitudinal and transverse stretching.
From DE-A - 195 15 137 a process for producing tubular films is known, according to which a cellulose solution at first is extruded to a tube, which tube on its way from the annular die outlet to the entry into the precipitation medium is stretched in the direction of extrusion and widened, i.e., extended at a ratio ranging between 1: 1 and 1: 10 by a gas pl es~ul e prevailing in the tube interior. By that extension, the tube is thus stretched transverse to the direction of extrusion.
A device of the initially defined kind, i.e., for producing cellulosic tubular films by extruding a solution of cellulose in a tertiary amine oxide into a precipitant present below the device, which device comprises an extrusion die having a subst~nt~ y annular extrusion gap, wherein a feed duct for pl~cipil~ll and a discharge duct for used precipitant are provided in the interior of the ring formed by the extrusion gap, may be taken from WO 95/07811. In that device, a spacer disc may be provided below the discharge duct in order to prevent the extruded tubular film from collapsing in the precipitation bath.
The prior art devices for the production of tubular films are complex in structure. It is, therefore, the object of the present invention to provide a device for the production of tubular films, which is of simpler construction.
The device according to the invention for producing cellulosic tubular films by extruding a solution of cellulose in a tertiary amine oxide into a precipitant present below the device, which device comprises an extrusion die having a substantially annular extrusion gap, wherein a supply duct for precipitant and a discharge duct for used precipitant are provided in the interior of the ring formed by the extrusion gap, is characterized in that the supply duct for the precipitant tt?lmin~tes below the discharge duct for the used precipitant.
CA 022~638 1998-11-19 It has been shown that in the device according to the invention the liquid level in the interior of the tube may be adjusted and, above all, kept constant in a simple manner. Furthermore, it has proved advantageous to the precipitating procedure? if the precipitant is allowed to stream opposite to the direction of extrusion, i.e., transport direction into the precipitation bath, in the interior of the tube. The present invention differs from the prior art also in this respect, since, as will be described below, fresh precipitant always gets into contact with film regions in which the cellulose is present in the precipitated state already to a high degree. On the other hand, the precipitant enriched most with amine oxide gets into contact with film regions in which the cellulose is present to a yet slightly plecipil~ted extent.
A preferred configuration of the device according to the invention is characterized in that a spacer is provided below the extrusion gap, which spacer preferably is designed to have a substantially circular periphery.
The cross sectional area of the spacer may be larger than the area formed by the ring of the extrusion gap. This enables stretching of the tubularly extruded solution transverse to the transport direction.
The cross sectional area of the spacer may, however, also be smaller than the area formed by the ring of the extrusion gap.
The spacer preferably is designed such that the size of the cross sectional area may be changed. This is feasible, for instance, with a disc, or a ring, including displaceable members in a manner analogous to an apertured diaphragm, in which the displaceable parts may slide on or within one another, thereby enabling the external diameter to be changed.
A change in the size of the cross sectional area may, furthermore, be reached in that the spacer is comprised of an elastic ring, for instance of rubber, to which air, water or the like may be fed. The diameter of the elastic ring is, thus, controllable via the medium contained in its interior. A variant of this embodiment consists in that no complete ring is used, but the inner side is comprised of a solid part of, e.g., steel or plastics and an elastic part is attached to the same. Another embodiment consists in a semi-shell, optionally comprised of segments, whose fixed point is displaceable, thereby ch~nging the external diameter (umbrella principle).
The invention also relates to a process for producing cellulosic tubular films, in which a solution of cellulose in a tertiary amine oxide is extruded through an extrusion die having a substantially annular extrusion gap, wherein the solution is molded in a tubular manner, which solution is transported into a precipitation bath and contacted with precipitant both on its irmer CA 022~638 1998-11-19 side and on its outer side, whereby the cellulose is precipitated and the tubular film is formed, which is characterized in that the precipitallt with which the tubularly molded solution is contacted on its inner side contains dissolved tertiary amine oxide whose concentration decreases in the transport direction of the tubularly molded solution.
In the process according to the invention, the tubularly molded solution may be stretched in the transport direction andlor transverse to the transport direction.
Stretching of the tubularly molded solution transverse to the transport direction may be effected by hydrostatic p,es~u,e or by gas pres~ule or by means of a spacer.
The tubular film molded by pleci~ila~ g the cellulose after transportation through the precipitation bath is dried, wherein the tubular film is preferably kept under tension in order to prevent shrinking.
The process according to the invention is particularly suitable for processing aqueous solutions of cellulose in aqueous N-methylmorpholine-N-oxide (NMMO).
A plef~lled configuration of the device according to the invention will be explained in more detail by way of the annexed drawing.
Fig. 1 schematically shows a cross section through the lower part of an extrusion device substantially comprising an annular die 1 having an annular extrusion gap 2, a supply duct 3 for fresh precipitant (water or an amine oxide/water mixture) and a discharge duct 4 for used precipitant.
The cellulose solution is pressed through the extrusion gap 2 via the annular spinning mass space 5, thereby extruding the cellulose solution in the form of a tubular film 6 into the air space present between the precipitation bath surface 7 and the lower side 8 of the annular die 1.
The tubularly extruded solution 6 is drawn off into the precipitation bath 7, in which it gets into contact with precipitant on its outer side, thereby causing the dissolved cellulose to coagulate and the amine oxide to be released into the precipitation bath. Precipitant is also in the interior of the tube 6 such that the cellulose coagulates also on its inner side. In doing so, amine oxide is released again.
In the Figure, the level 8 of the precipitant present in the interior of the tube 6 is on equal height with the precipitation bath 7. Precipitant may be introduced into the interior of the tube CA 022~638 1998-11-19 6 via the supply duct 3 and drawn off via the discharge duct 4. In this manner, the level 8 of the precipitant may be adjusted in the interior of the tube 6.
In the process according to the invention, the level 8 of the precipitant present in the interior of the tube 6 also may be adjusted to be higher or lower than the level of the precipitation bath 7. The composition of the precipitant in the interior of the tube 6 may differ from that of the precipitation bath.
The tubular film 6 is drawn off via deflection means 10 and thereby stretched in the transport direction, i.e., in the direction toward the precipitation bath 7.
The tubular film 6 is drawn over a spacer 9. That spacer 9 has the form of a circular disc firmly connected with the die 1 by means of rods 11. The spacer 9 comprises continuous bores 9a for mass transfer. The supply duct 3 passes through the spacer 9. The disc also may be replaced with a spacer ring.
The tube 6 is extended by the spacer 9, this corresponding to stretching transverse to the transport direction. It is evident that such stretching transverse to the transport direction increases with the size of the circular spacer.
By feeding fresh plecipitant via the supply duct 3 and discharging used, i.e. amine-oxide-cont~ining, precipitation bath via the discharge duct 4, which terrnin~tes above the supply duct 3, the concentration of amine oxide increases in the direction toward the level 8 or, in other words decreases in the transport direction of the tubular film 6.
On the end of the supply duct 3 there may also be provided baffle plates (not illustrated) in order to divert the liquid stream from the supply duct 3 upwardly in the direction of the level 8.
Stretching transverse to the transport direction may also be obtained by means of hydrostatic pres~u-e instead of the spacer. To this end, the level 8 of the precipitant within the tube 6 simply is adjusted to be higher than the level 7 of the precipitation bath. In doing so, extension is caused by the pressure of that part of the precipitant present in the interior of the tube 6, which is above the level 7.
Extension also may be obtained by means of gas pleS~ule, wherein the die 1 must, of course, be provided with a gas feed (not shown), by means of which the tubular film 6 is infl~te~l in the space provided between the lower side 8 of the die and the precipitation bath 7. The gas CA 022~638 1998-11-19 may also be replaced, which means that operation is effected at a gas excess. In that case, also a gas discharge duct (not illustrated), of course, is to be provided on the die.
Claims (12)
1. A device for the production of cellulosic tubular films by extruding a solution of cellulose in an aqueous tertiary amine oxide into a precipitant present below the device, which device comprises an extrusion die having a substantially annular extrusion gap, wherein a supply duct for precipitant and a discharge duct for used precipitant are provided in the interior of the ring formed by the extrusion gap, characterized in that the supply duct (3) for the precipitant terminates below the discharge duct (4) for the used precipitant.
2. A device according to claim 1, characterized in that a spacer (9) is provided below the extrusion gap (2).
3. A device according to claim 2, characterized in that the spacer (9) is designed to have a substantially circular periphery.
4. A device according to any one of claims 2 or 3, characterized in that the cross sectional area of the spacer (9) is larger than the area formed by the ring of the extrusion gap (2).
5. A device according to any one of claims 2 to 4, characterized in that spacer (9) is designed such that its cross sectional area may be changed.
6. A process for producing cellulosic tubular films, in which a solution of cellulose in an aqueous tertiary amine oxide is extruded through an extrusion die having a substantially annular extrusion gap, wherein the solution is molded in a tubular manner, which solution is transported into a precipitation bath and is contacted with a precipitant both on its inner side and on its outer side, whereby the cellulose is precipitated and the tubular film is formed, characterized in that the precipitant with which the tubularly molded solution (6) is contacted on its inner side contains dissolved tertiary amine oxide whose concentration decreases in the transport direction of the tubularly molded solution.
7. A process according to claim 6, characterized in that the tubularly molded solution is stretched in the transport direction.
8. A process according to any one of claims 6 or 7, characterized in that the tubularly molded solution is stretched transverse to the transport direction.
9. A process according to claim 8, characterized in that the tubularly molded solution is stretched transverse to the transport direction by means of hydrostatic pressure or gas pressure.
10. A process according to claim 8, characterized in that the tubularly molded solution is stretched transverse to the transport direction by means of a spacer (9).
11. A process according to any one of claims 6 to 10, characterized in that the tubular film (6) molded by precipitating the cellulose after transportation through the precipitation bath is dried while keeping the tubular film (6) under tension in order to prevent shrinking.
12. A process according to one or several of claims 6 to 11, characterized in that N-methylmorpholine-N-oxide is used as a tertiary amine oxide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ATA495/97 | 1997-03-21 | ||
| AT0049597A AT404595B (en) | 1997-03-21 | 1997-03-21 | DEVICE AND METHOD FOR PRODUCING CELLULOSIC TUBE FILMS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2255638A1 true CA2255638A1 (en) | 1998-10-01 |
Family
ID=3492124
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002255638A Abandoned CA2255638A1 (en) | 1997-03-21 | 1998-03-20 | Device and method for producing cellulose tubular films |
Country Status (13)
| Country | Link |
|---|---|
| US (1) | US20020167110A1 (en) |
| EP (1) | EP0904187B1 (en) |
| JP (1) | JP2000510784A (en) |
| CN (1) | CN1081529C (en) |
| AT (2) | AT404595B (en) |
| AU (1) | AU734818B2 (en) |
| BR (1) | BR9804789A (en) |
| CA (1) | CA2255638A1 (en) |
| DE (1) | DE59805593D1 (en) |
| ES (1) | ES2183333T3 (en) |
| ID (1) | ID20429A (en) |
| NO (1) | NO314026B1 (en) |
| WO (1) | WO1998042492A2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9823086D0 (en) * | 1998-10-21 | 1998-12-16 | Devro Plc | Film manufacturing method |
| AU6221399A (en) * | 1998-10-21 | 2000-05-08 | Devro Plc | Cellulose extrusion |
| DE10035798A1 (en) * | 2000-07-22 | 2002-01-31 | Kalle Nalo Gmbh & Co Kg | Method and device for producing a seamless film tube and seamless film tube |
| JP4547115B2 (en) * | 2001-08-29 | 2010-09-22 | 富士フイルム株式会社 | Method for producing optical compensation film |
| AT514137A1 (en) | 2013-04-05 | 2014-10-15 | Lenzing Akiengesellschaft | Polysaccharide fiber and process for its preparation |
| AT514136A1 (en) | 2013-04-05 | 2014-10-15 | Lenzing Akiengesellschaft | Polysaccharide fiber with increased fibrillation capability and process for its preparation |
| AT514123B1 (en) | 2013-04-10 | 2015-06-15 | Lenzing Akiengesellschaft | Polysaccharide film and process for its preparation |
| AT514468A1 (en) | 2013-06-17 | 2015-01-15 | Lenzing Akiengesellschaft | High absorbency polysaccharide fiber and its use |
| AT514474B1 (en) | 2013-06-18 | 2016-02-15 | Chemiefaser Lenzing Ag | Polysaccharide fiber and process for its preparation |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US416536A (en) * | 1889-12-03 | Sheet-metal can | ||
| DE367972C (en) * | 1923-01-30 | Glanzstoff Ag | Process for the production of tubular cellulose skins from cellulose solutions | |
| DE549410C (en) * | 1928-01-27 | 1932-04-27 | Richard Weingand Dipl Ing | Device for the continuous production of seamless, flexible hoses from cellulose solution |
| BE419316A (en) * | 1936-01-09 | 1900-01-01 | ||
| BE620293A (en) * | 1965-02-04 | 1900-01-01 | ||
| US4164536A (en) * | 1978-04-18 | 1979-08-14 | Teepak, Inc. | Method and apparatus for the manufacture of fibrous casing |
| AT403584B (en) * | 1993-09-13 | 1998-03-25 | Chemiefaser Lenzing Ag | METHOD AND DEVICE FOR PRODUCING CELLULOSIC FLAT OR TUBE FILMS |
| 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 |
-
1997
- 1997-03-21 AT AT0049597A patent/AT404595B/en not_active IP Right Cessation
-
1998
- 1998-03-20 BR BR9804789A patent/BR9804789A/en not_active Application Discontinuation
- 1998-03-20 JP JP10544518A patent/JP2000510784A/en active Pending
- 1998-03-20 EP EP98909211A patent/EP0904187B1/en not_active Expired - Lifetime
- 1998-03-20 CA CA002255638A patent/CA2255638A1/en not_active Abandoned
- 1998-03-20 DE DE59805593T patent/DE59805593D1/en not_active Expired - Fee Related
- 1998-03-20 AU AU63850/98A patent/AU734818B2/en not_active Ceased
- 1998-03-20 CN CN988002469A patent/CN1081529C/en not_active Expired - Fee Related
- 1998-03-20 AT AT98909211T patent/ATE224286T1/en not_active IP Right Cessation
- 1998-03-20 ES ES98909211T patent/ES2183333T3/en not_active Expired - Lifetime
- 1998-03-20 WO PCT/AT1998/000074 patent/WO1998042492A2/en active IP Right Grant
- 1998-03-20 ID IDW980117A patent/ID20429A/en unknown
- 1998-11-20 NO NO19985399A patent/NO314026B1/en not_active IP Right Cessation
-
2002
- 2002-06-27 US US10/185,361 patent/US20020167110A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| CN1219148A (en) | 1999-06-09 |
| AU734818B2 (en) | 2001-06-21 |
| ES2183333T3 (en) | 2003-03-16 |
| ATA49597A (en) | 1998-05-15 |
| NO314026B1 (en) | 2003-01-20 |
| NO985399D0 (en) | 1998-11-20 |
| DE59805593D1 (en) | 2002-10-24 |
| EP0904187A2 (en) | 1999-03-31 |
| EP0904187B1 (en) | 2002-09-18 |
| US20020167110A1 (en) | 2002-11-14 |
| ATE224286T1 (en) | 2002-10-15 |
| WO1998042492A3 (en) | 1999-01-21 |
| WO1998042492A2 (en) | 1998-10-01 |
| EP0904187A3 (en) | 1999-07-28 |
| AU6385098A (en) | 1998-10-20 |
| NO985399L (en) | 1998-11-20 |
| CN1081529C (en) | 2002-03-27 |
| ID20429A (en) | 1998-12-10 |
| AT404595B (en) | 1998-12-28 |
| BR9804789A (en) | 1999-08-17 |
| JP2000510784A (en) | 2000-08-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |