EP1151787A2 - Bildung einer Lösung aus Fluiden mit niedriger Mischbarkeit und grossem Unterschied in der Viskosität - Google Patents

Bildung einer Lösung aus Fluiden mit niedriger Mischbarkeit und grossem Unterschied in der Viskosität Download PDF

Info

Publication number
EP1151787A2
EP1151787A2 EP01117775A EP01117775A EP1151787A2 EP 1151787 A2 EP1151787 A2 EP 1151787A2 EP 01117775 A EP01117775 A EP 01117775A EP 01117775 A EP01117775 A EP 01117775A EP 1151787 A2 EP1151787 A2 EP 1151787A2
Authority
EP
European Patent Office
Prior art keywords
mixing
polymer
helical
spin agent
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP01117775A
Other languages
English (en)
French (fr)
Other versions
EP1151787A3 (de
EP1151787B1 (de
Inventor
Robert E. Albers
Arthur William Etchells
Joseph Daniel Gutmann, Jr.
Edgar W. Slocum
Ashok H. Shah
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority claimed from EP97913933A external-priority patent/EP0935496B1/de
Publication of EP1151787A2 publication Critical patent/EP1151787A2/de
Publication of EP1151787A3 publication Critical patent/EP1151787A3/de
Application granted granted Critical
Publication of EP1151787B1 publication Critical patent/EP1151787B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • D01D1/00—Treatment of filament-forming or like material
    • D01D1/06—Feeding liquid to the spinning head
    • D01D1/065—Addition and mixing of substances to the spinning solution or to the melt; Homogenising
    • 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
    • D01D5/11—Flash-spinning

Definitions

  • This invention relates to a process and system for mixing fluids and particularly to mixing fluids that are not readily dissolved together and fluids that have very substantial differences in their relative viscosities.
  • TYVEK® spunbonded olefin For many years, E. I. du Pont de Nemours and Company (DuPont) has been making TYVEK® spunbonded olefin. Commercial end uses for TYVEK® spunbonded olefin sheets have been developed for mailing envelopes, housewrap, apparel, medical packaging and many other uses.
  • the process for making the spunbonded olefin has been the subject of numerous patents including US 3,081,519 to Blades et al., US 3,169,899 to Steuber, US 3,227,794 to Anderson et al., US 3,484,899 to Smith, US 3,497,918 to Pollock et al., US 3,860,369 to Brethauer et al., US 4,352,650 to Marshall, US 4,554,207 to Lee, and US 5,123,983 to Marshall.
  • the basic steps of this process are (1) forming a solution of polyolefin polymer with Freon® 11 spin agent, and (2) flash spinning the solution in a spin cell.
  • Freon® is a registered trademark owned by DuPont.
  • Freon® 11 spin agent is a chlorofluorocarbon (CFC) and is believed to be a cause of ozone depletion. The use of most CFC materials are targeted to be eventually banned.
  • DuPont has sought a substitute spin agent for use in the continued manufacturing of spunbonded olefins. Unfortunately, there is not a readily available spin agent that would be a simple substitute for the Freon® 11 spin agent. Although it has been found that spunbonded olefins may be made using one of a number of different spin agents, each potential alternative spin agent gives rise to numerous production process or product quality issues. Among the alternative spin agents that have been found for making TYVEK® spunbonded olefin are certain hydrocarbons, including pentane. An important issue for hydrocarbon spin agents is their flammability whereas Freon® 11 spin agent is not at all flammable.
  • the issues of flammability and explosivity are substantial when one considers that the spin agents will be subjected to high pressure and high temperature during the flash spinning processes.
  • the solution provided to the spin cell is approximately eighty percent spin agent by weight so the amount of hydrocarbon that may be subjected to the high pressures and temperatures associated with flash spinning is not minimal.
  • the solutioning system in the process for making spunbonded olefin is the portion of the system that mixes the polymer with the spin agent to form a homogenous solution suitable for spinning into plexifilaments.
  • the solutioning system in current use is generally illustrated in Figure 1.
  • the system comprises a very large drum 12 arranged to receive measured amounts of polyethylene pellets and spin agent.
  • the polyethylene pellets are supplied from a hopper 14 and the spin agent is supplied from a tank 15.
  • the drum 12 is sized to hold the pellets and spin agent for an extended period of time (e.g. hours) and is approximately 5000 gallons.
  • the drum is closed and maintained at approximately room temperature and pressure.
  • the pellets are rapidly stirred by a rotating agitator 19 to form a uniform slurry.
  • the pellets and spin agent are drawn from the drum 12 into a pressure pump 21 which pumps the polymer slurry so as to raise the slurry pressure while directing the slurry through a heat exchanger 22 to raise the slurry temperature.
  • the high pressure, high temperature slurry is then provided to a dissolver tank 23 where the slurry is stirred and mixed by an agitator 24 until the mixture becomes a homogeneous solution suitable for flash spinning in a spin cell, schematically indicated at 25.
  • the system provides for large amounts of the solution in both the dissolver tank 23 and the drum 12 at any given time.
  • a plant may spin anywhere from 2000 to 10,000 pounds of polymer per hour and the solution from which this polymer is spun is ordinarily comprised of 75 to 90 percent spin agent by weight.
  • the conventional solutioning process of Figure 1 requires that tank 23 hold very large amounts of spin agent at high pressure and temperature for extended periods of time. When the non-flammable spin agent is replaced with a highly flammable spin agent, such a large volume of flammable spin agent at high pressure and temperature would raise serious safety concerns.
  • a solutioning system for mixing the polymer with a solvent to form a spin solution is also needed wherein the overall solutioning system has a reduced volume of spin agent as compared to current and conventional solutioning systems.
  • a mixer for mixing at least two fluid materials wherein the two fluid materials have substantially different viscosities.
  • the apparatus includes a generally cylindrical elongate tube forming an outer shell and defined by a longitudinal axis and an inner wall spaced at a generally uniform distance from the axis.
  • a shaft is arranged along the axis with a plurality of flights attached thereto. The flights are arranged to provide substantial shear forces on the polymer and fluid mixture while generally not differentially conveying one of the two phases, which have a viscosity ratio of more than 10,000 to 1, causing transient fluctuations in the ratio of spin agent to polymer.
  • the objects of the present invention may also be characterized as a solutioning system for mixing a polymer and a spin agent wherein the spin agent and polymer which may be chemically compatible but are not readily miscible.
  • the solutioning system forms a high pressure and temperature spin solution suitable for flash spinning plexifilaments and includes a heating mechanism for melting the polymer and a pressure creating device for raising the pressure of the molten polymer.
  • the system further includes a mechanical mixer having a longitudinal generally cylindrical housing having an inner wall and a shaft mounted for rotation in the housing. The mechanical mixer also includes flights which are arranged on said shaft to provide shear forces on the polymer and spin agent within the chamber while not causing differential conveying of the material in the housing.
  • Another aspect of the present invention relates to a process for mixing two fluid materials which have low miscibility and a viscosity ratio of at least 10,000 to 1, wherein the process comprises adding the highly viscous fluid to a mechanical mixer, adding a portion of the low viscosity fluid, and agitating the two materials in the mixer in a first mixer section wherein the fluids are not differentially conveyed.
  • a further aspect of the present invention is a mixing element for a mechanical mixing apparatus suited for being rotated within a generally cylindrical housing.
  • the mixing element includes a mounting shaft and flights extending outwardly from the mounting shaft.
  • the mixing element provides a pressure drop as fluid passes through the cylindrical housing but wherein the pressure drop is substantially the same regardless of the speed at which the mixing element rotates with the cylindrical housing.
  • the solutioning system 100 is used to create a homogenous solution of polyolefin fiber forming polymer and a suitable spin agent for flash spinning plexifilaments in a spin cell 170.
  • the solutioning system 100 is an integrated system in that it combines a number of components and subsystems which cooperate to provide a high pressure, high temperature environment for forming a uniform solution which is suitable for flash spinning plexifilaments.
  • the solution system 100 includes a hopper 110 for storage and delivery of the polyolefin pellets.
  • the pellets are provided to one end of an extruder 120 to heat and melt the pellets.
  • the extruder 120 is a conventional twin screw design including an elongate tubular pressure chamber 121 with a pair of screws 122 arranged to carry the polymer along the chamber 121 while squeezing and compressing the same.
  • the screws 122 include helical auger-like flights 126 on a shaft which is driven by a powerful motor 124.
  • the polymer emerges as a continuous, molten mass of very thick, highly viscous fluid material.
  • the molten polyolefin is then directed to a gear pump 130.
  • the gear pump 130 is of conventional design to convey a thick fluid at a range of predetermined rates.
  • the gear pump 130 pushes the molten polyolefin at a predetermined rate through the remainder of solution system 100 and also provides the high pressures that are required to form the homogeneous solution.
  • the molten polymer is then directed into the end of a mechanical mixer 140.
  • the mechanical mixer 140 generally comprises a long, generally cylindrical chamber 141 with a rotatable shaft 142 extending generally along the center of the long chamber 141.
  • a motor 144 rotates the shaft 142 which causes an array of elements attached to the shaft 142 to mix and blend a low viscosity spin agent into the polymer.
  • the structure of the mixer 140 and the elements on the shaft 142 will be further discussed in greater detail below. It is in the mechanical mixer 140 that the spin agent and polymer are first contacted to begin forming the homogenous solution.
  • the spin agent is stored in a tank 115 and provided through a spin agent injection system, generally indicated by the number 150 to the mechanical mixer 140. It should be noted that the spin agent is added to the polymer in several successive stations along the mechanical mixer 140 and further amounts of spin agent are provided to the polymer downstream of the mechanical mixer in static mixer section 160.
  • the spin agent injection system 150 provides the spin agent through positive displacement pumps 151 and 152 to provide predetermined flow rates of the spin agent that are in accordance with the rate of the gear pump 130 to produce a solution with the ratio of spin agent to polymer that is desired for flash spinning.
  • the spin agent may be heated (or cooled) as necessary by heat exchangers 154 and 155 prior to being mixed with the molten polymer.
  • the spin agent is directed to the polymer at several injection stations 156, 157, and 158 along the chamber 141 of the mechanical mixer 140.
  • the polymer and a small amount of spin agent are mixed together in the mechanical mixer 140 and are moved along therein by the polymer being pushed by the gear pump 130 into the mechanical mixer 140.
  • the polymer and spin agent move along the mechanical mixer 140, they are blended to form a homogeneous solution prior to reaching the second spin agent injection station 157.
  • This first solution has a slightly lower viscosity than the neat molten polymer and also achieves successively lower viscosities as more spin agent is injected at the second and successive spin agent injection stations 157 and 158.
  • the solution is discharged from the opposite end of the mechanical mixer 140 and directed to a static mixer section 160 wherein more spin agent is added to bring the solution to a final polymer to spin agent ratio for flash spinning.
  • the static mixer section 160 comprises one or more static mixers (also known as “motionless mixers"), which in the preferred embodiment comprises three static mixing elements 161, 162, and 163.
  • static mixers also known as "motionless mixers”
  • the static mixer spin agent injection stations 165 and 166 Immediately prior to the first static mixer 161 is the first in a second series of spin agent injection stations which will be called the static mixer spin agent injection stations 165 and 166.
  • the static mixers 161, 162 and 163 include internal structures to create a significantly tortuous path that effectively mixes the solution as it moves through the static mixer.
  • the internal structure is preferably similar to designs commonly called “Koch Mixers SMX" which are available from Koch Industries of Wichita, Kansas.
  • a second static mixer spin agent injection station 166 may be positioned between the first and second static mixers 161 and 162 after which the solution may be subjected to two final mixing steps in static mixers 162 and 163. From the last static mixer 163 the solution is provided to the spin cell generally indicated by the number 170.
  • each of the static mixers include a mixing zone and a relaxation zone.
  • the second static mixer 162 in Figure 2, includes the mixing portion 162A wherein the solution at a particular cross sectional plane is thoroughly mixed such that solution at the edges of the flow path is mixed with fluid at the center of the flow path and vice versa.
  • the mixing portion 162A all parts of solution passing through the mixer tends to flow at a single rate whether at the edge of the flow path or towards the center of the flow path.
  • the relaxation zone 162B the portion of the solution in the middle of the flow path moves faster than portions of the solution near the edges of the flow path.
  • the particular cross sectional plane of solution entering the next mixer at any given time includes portions of the solution of polymer and spin agent that were first mixed at a number of different times.
  • the solution is thoroughly mixed again across the cross sectional plane of the flow path.
  • the description of the solution system 100 now will focus on some of the details of the components and subsystems thereof so that they may be better understood.
  • One of the central components of the solution system 100 is the mechanical mixer 140.
  • the mixing of the spin agent and polymer has provided considerable challenges.
  • the hydrocarbon spin agent pentane has a viscosity of approximately 0.2 centipoise (cP) while molten polyethylene has a viscosity of approximately 6,400,000 cP (1 cp equals 0.001 pascal seconds).
  • a polyolefin polymer such as polyethylene, does not readily absorb a hydrocarbon spin agent such as pentane.
  • the spin agent only gradually diffuses into the polymer rich phase.
  • the spin agent must be well blended into the polymer or polymer solution to hasten the formation of a homogenous solution.
  • the solution must maintain an elevated pressure and temperature suitable for flash spinning.
  • the mechanical mixer 140 must effect mixing without creating an excessive pressure drop which will cause the solution to fall below the cloud point pressure of the solution which pressure would be unsuitable for flash spinning.
  • the mechanical mixer 140 comprises a long, generally cylindrical chamber 200 with a drive shaft 205 running generally along the axis thereof.
  • the drive shaft 205 is connected to a suitable drive motor 208 positioned at the left end of the chamber 200.
  • the chamber includes a polymer inlet 210 wherein the molten polymer is directed from the extruder 120 via the gear pump 130 (shown in Figure 2).
  • a threaded seal portion 211 between the polymer inlet and the drive motor 208 is arranged to form a seal at the first end of the chamber 200 using the molten polymer.
  • the threaded seal portion 211 includes two sets of counter oriented threads arranged closely spaced from the inner wall of the chamber 200. The two sets of counter oriented threads are each oriented to push polymer toward the other set of threads. Thus, during operation, some of the thick molten polymer will move into the annular space between the inner wall of chamber 200 and the counter oriented threads of the threaded seal portion 200.
  • the molten polymer in this annular space gets squeezed between the two sets of countered oriented threads and the proximate inner wall of the chamber 200 thereby sealing the remainder of the chamber 200 from the drive motor.
  • the seal at the seal portion 211 is effective if it (1) maintains the pressure in the mechanical mixer at a level suitable for mixing spin agent and polymer, and (2) prevents leakage of all of the lower viscosity spin agent.
  • the polymer inlet is positioned between the seal portion 211 and the first spin agent injection station 156 which help to keep the spin agent away from seal portion 200 and the interface between cylindrical chamber 200 and the rotating shaft 205.
  • the polymer moves from the inlet 210 on through the chamber 200 along the rotating shaft 205 to the first spin agent injection station 156 where spin agent first contacts the molten polymer.
  • the spin agent injection system 150 is best understood by reference particularly to Figures 5 and 6 and also to Figure 3.
  • the first spin agent injection station 156 includes first and second perforated injector plates 215 and 216 mounted to the drive shaft 205. Each of the injector plates 215 and 216 include a plurality of holes through which the polymer mass is directed and divided into a plurality of flows creating substantial boundary areas for the spin agent to contact the polymer. Between the two injector plates are a plurality of injector nozzles 221, 222, 223, and 224 which are spaced about the periphery of the chamber 200.
  • the spin agent is well distributed about the annular space between the shaft 205 and the inner wall of the chamber 200.
  • the first spin agent injection station 156 is supplied with spin agent through a common feed line 181.
  • the feed line 181 includes a metering valve 182 which, in conjunction with similar metering valves at the other injection stations regulates the portion of spin agent that is injected at each station.
  • the feed line directs the spin agent into each of four nozzle lines 183, 184, 185 and 186 leading to each of the four injector nozzles 221, 222, 223, and 224.
  • Each of the respective nozzle lines includes a restrictor valve 183A, 184A, 185A, and 186A which effectively creates a generally uniform predetermined flow for a given pressure drop through each of the nozzle lines.
  • the restrictor valves enable the injection system 150 to clear a clogged injector nozzle by applying a high pressure to the clogged nozzle to clear the clog. As a nozzle clogs, the flow through the line decreases which in turn reduces the pressure drop at the corresponding restrictor valve. The pressure increases behind the clog until the clog is pushed out into the chamber 200.
  • restrictor valves may alternatively be replaced by orifice plates or capillaries or the like.
  • the second and third spin agent injection stations 157 and 158 are similar to the first spin agent injection station 156 and each include four injection nozzles with corresponding restrictor valves. Thus, detailed drawings of the second and third injection stations are not believed necessary for explanation thereof. However, the spin agent injection stations may be arranged in an alternative arrangement as illustrated in Figure 7.
  • the second alternative embodiment of an injection station shown in Figure 7 is generally indicated by the number 190 and includes a single sleeve 191 overlying the shaft 205 rather than the pair of perforated injector plates.
  • the sleeve includes a radial flange 192 at the upstream end thereof to create an area of smaller annular space between the radial flange 192 and the inner wall of the chamber 200, followed by an area of larger annular space.
  • the second injection station embodiment would include injector nozzles which are essentially the same as the injector nozzles of the first embodiment of Figure 6.
  • the mechanical mixer 140 includes four groupings of mixing elements wherein the first grouping includes three mixing elements 231, 232 and 233.
  • the first two mixing elements 231 and 232 of the first grouping are duplicates of one another while the third mixing element 233 is a differently styled mixing element.
  • the mixing elements 231, 232 and 233 are preferably designed as interchangeable sections such that the various sections can be switched and replaced to enable the creation of a wide variety of different styled mixers. This has the advantage of providing greater flexibility in design without adding tremendously to the cost.
  • the forward helical mixing element 300 comprises a hollow core shaft 305 adapted to be slipped onto the main mixer shaft 205 A suitable arrangement may be provided to lock the hollow core shaft 305 to the drive shaft 205 such as a conventional key way or by pins, etc.
  • the mixing section 300 further includes a series of helical flights 311, 312, 313, and 314 set out and away from the hollow core shaft 305 and having an outer radius slightly smaller than the radius of the inner wall of the chamber 200.
  • the helical flights are fixed to the hollow core shaft by a plurality of radiating flight support legs 316.
  • the flight support legs 316 are preferably welded onto the hollow core shaft but may alternatively be attached by screw thread or other suitable arrangement.
  • the ends of the helical flights are adapted to terminate into end rings 318 and 319 which are also spaced from the core shaft 305.
  • the preferred embodiment is arranged such that the length of the mixing section 300 is approximately twice the diameter of the periphery of the helical flights and each flight makes one complete revolution around the core shaft 305 in a ribbon-like manner.
  • the forward helical mixing element 300 includes a space between the exterior of the hollow core shaft and the inner portions of both the helical flights and the end rings.
  • the forward helical mixing element 300 rotates such that the polymer is pushed forward in the mechanical mixer 140.
  • the illustrated mixing element 300 is characterized as a forward helix mixing section.
  • a reverse helical type mixing element is configured essentially the same as a forward helical mixing element except that the flights are oriented to push the polymer in the opposite direction.
  • differential conveying the thicker, more viscous fluid in the mixer is conveyed at a different speed or even in a direction opposite from the lighter less viscous fluid. It should be understood that differential conveying applies to the polymer and spin agent while they are still dispersed and not to the homogeneous solution once it is formed.
  • a reverse helical mixing element was better at dispersing the spin agent and polymer so as to enhance absorption.
  • the reverse helical mixing element opposes the forward progress of the solution through the chamber 200. This resistance creates a substantial pressure drop in the solution.
  • the cloud point of the solution particularly in the initial high viscosity zones, is at a relatively high pressure.
  • any substantial pressure drop risks bringing the pressure of the solution to a level which risks counteracting the effects of the mixing.
  • the spin agent and polymer that has already formed a homogeneous solution will separate.
  • the solutioning system can only tolerate a certain amount of pressure drop.
  • the counterhelix mixing element 400 comprises a hollow core shaft 405, flight support legs 416 and end rings 418 and 419.
  • the counterhelix mixing element 400 similar to the forward helical mixing element 300, also includes four helical blades 411, 412, 413 and 414 which are spaced from the hollow core shaft 405.
  • the counterhelix mixing element 400 includes additional structure not found in the forward helical mixing element 300.
  • two peripheral reverse oriented helical blades 421 and 422 are interlaced through the forward oriented helical blades 411, 412, 413 and 414.
  • the reverse oriented helical blades are, like the forward oriented helical blades, each spaced from the hollow core shaft 405.
  • the mixing element 400 further includes two additional reverse oriented helical blades called shaft mounted helical blades 425 and 426 which are positioned effectively between the reverse peripheral helical blades 421 and 422 but are mounted directly onto the hollow core shaft 405.
  • the shaft mounted reverse oriented helical blades 425 and 426 extend radially outwardly slightly more than half the distance from the hollow shaft to the inner wall of the chamber 200.
  • the radial projection of the shaft mounted helical blade is also greater than the spacing of the peripherally mounted forward and reverse helical blades 411, 412, 413, 414, 421 and 422 from the core shaft 405.
  • the shaft mounted reverse oriented helical blades 425 and 426 are also segmented, or not continuous, having breaks corresponding to about every other intersection with a forward oriented helical blade.
  • the peripheral mounted forward and reverse oriented blades 411, 412, 413,414, 421 and 422 are all continuous and where they intersect are welded or otherwise configured to meld together.
  • the shaft mounted helical blades 425 and 426 limit the availability of a direct flow path along the hollow core shaft 405. In this manner, differential conveying is thus reduced by creating a rather tortuous path through the mixing element 400. Without wishing to be limited by theory, it is believed that the greatest amount of shearing that causes the mixing of the polymer and spin agent is at the peripheral edges of the helical blades adjacent the inner wall of the chamber 200. It is further believed that the shaft mounted helical blades 425 and 426 prevent the polymer solution from bypassing or avoiding the most productive portions of the mixer where the greatest amount of shearing is generated.
  • a further structural feature of the counterhelix mixing element 400 is that the forward oriented peripheral blades include peripheral notches 431 cut therein to relieve pressure at the inner wall of the chamber 200.
  • the sizes of the notches are preferably cut such that the respective opposite notch faces 432 do not overlap in the longitudinal direction. In other words, a line may be drawn parallel to the axis of the hollow shaft core 405 that extends through the notch 431 without intersecting either of the opposite notch faces 432.
  • the notches are arranged on the forward oriented blades 411, 412, 413, and 414 in a manner such that the notched portion of each blade is followed by a solid portion on the next blade as the mixing element 400 rotates. With this arrangement, matter that passes through any notch will be impacted by the next one of the forward oriented rotating blades and polymer, spin agent and solution are not allowed to build up on the inner wall of chamber 200.
  • the counterhelix mixing element 400 has been found empirically not to differentially convey fluids of different viscosity. This is also accomplished by the design of the mixing element 400 that does not impart any forward motion or reverse motion on the fluid in the chamber 200. Solution passing through the counterhelix mixing element 400 experiences the same pressure drop regardless of whether the element is rotating and regardless of the rotational speed. While it is known that the design described above achieves the objective of mixing fluids of very different viscosities without significant differential conveying of the fluids being mixed, the ranges of the parameters have not yet been extensively explored. Clearly, the potential parameters and variability of the parameters are considerable. Suffice it to note that the counterhelix mixing element of the present invention creates substantial dispersion of the fluids such that the fluids have the opportunity for ready absorption while substantially not rendering effects that have the strong consequence of undoing the intended object.
  • the first mixing element 231 comprises a counterhelix mixing element 400.
  • the second mixing element 232 also comprises a counterhelix mixing element 400.
  • a first intervening perforated plate 235 which is essentially of the same construction as the perforated injection plates 215 and 216.
  • the intervening perforated plate 235 provides substantial shear on the mass of polymer and spin agent to hasten the absorption of the free spin agent therein.
  • the third mixing element 233 is a forward helical mixing element 300 so as to reduce the amount of further pressure drop in the solutioning system 100.
  • the forward oriented helical mixing elements 300 are believed to not necessarily render good mixing and in some circumstances tend to separate the fluids.
  • a stable solution is formed and a forward helical mixing element 300 is not going to separate the spin agent from the polymer unless the pressure falls below the cloud point.
  • a second intervening perforated plate 236 similar to the first perforated plate 235.
  • the first preferred embodiment of the mechanical mixer 140 further includes a second grouping of three mixing elements 251, 252 and 253 which follows the second injection station 157.
  • the second grouping is very similar to the first.
  • the fourth and fifth mixing elements 251 and 252 are counterhelix mixing elements 400.
  • the sixth mixing element 253 is a forward oriented helical mixing element 300.
  • Third and fourth intervening perforated plates 255 and 256 are positioned between the fourth, fifth and sixth mixing elements 251, 252 and 253.
  • the mechanical mixer further includes a third grouping of three mixing elements 271, 272 and 273 which follow the third injection station 158.
  • the seventh, eighth and ninth mixing elements 271, 272 and 273 are all counterhelix mixing elements 400 with intervening perforated plates 275 and 276 positioned thereinbetween.
  • the preferred embodiment includes one further injection station 159 for flexibility of design; however, it is closed off and not used at present.
  • the fourth and last injection station provides demarcation between the third grouping and the last grouping of mixing elements.
  • the mechanical mixer 140 includes a final grouping of mixing elements, this last grouping includes four mixing elements 291, 292, 293, and 294.
  • the mixing elements of the last group are reverse helical mixing elements as described above.
  • the reverse helical mixing elements are essentially constructed the same as the forward helical mixing element 300 except the flights are oriented in the opposite direction to push the fluid backwards in the mechanical mixer 140.
  • the reverse oriented helical elements tend to provide good mixing.
  • the mixing elements 291, 292, 293, and 294 provide some final mixing before the solution is discharged to the static mixer system 160.
  • Intervening perforated plates 295, 296 and 297 are positioned between the elements as in the previous groupings.
  • a discharge plate 298 is arranged at the end of the shaft 205 to center the same. Once the polymer passes the discharge plate, it is discharged through outlet 299.
  • FIG 4 a second preferred embodiment of the mechanical mixer 140 is shown which is quite similar to the embodiment shown in Figure 3 .
  • the discussion will be limited to the differences between the first and second preferred embodiments.
  • Corresponding components in Figure 4 are indicated with similar reference numbers except that the hundredths place includes a "5" rather than a "2".
  • the second intervening plate is replaced with a spacer 536.
  • the fourth, sixth, eighth, ninth and tenth perforated plates are substituted with spacers in the embodiment of the invention shown in Figure 4.
  • the mechanical mixer of the second preferred embodiment should result in less pressure drop and slightly less mixing than the first mixer embodiment of Figure 3.
  • the number of perforated plates may be adjusted if more or less thorough mixing is necessary to provide a solution suitable for flash spinning.
  • some of the perforated plates used in the mechanical mixer 140 may have different sizes of perforations and different numbers of openings.
  • the larger size perforations are used at the first end of the mixer where the polymer has a higher viscosity. Plates having a larger number of smaller perforations are typically used later in the mixer 140 where the viscosity of the solution is lower and it is desired to be sure that all the spin agent is adsorbed into the polymer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
EP01117775A 1996-11-01 1997-10-31 Bildung einer Lösung aus Fluiden mit niedriger Mischbarkeit und grossem Unterschied in der Viskosität Expired - Lifetime EP1151787B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US2953996P 1996-11-01 1996-11-01
US29539P 1996-11-01
EP97913933A EP0935496B1 (de) 1996-11-01 1997-10-31 Bildung einer lösung aus fluiden mit niedriger mischbarkeit und grossem unterschied in der viskosität

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
EP97913933A Division EP0935496B1 (de) 1996-11-01 1997-10-31 Bildung einer lösung aus fluiden mit niedriger mischbarkeit und grossem unterschied in der viskosität

Publications (3)

Publication Number Publication Date
EP1151787A2 true EP1151787A2 (de) 2001-11-07
EP1151787A3 EP1151787A3 (de) 2002-01-30
EP1151787B1 EP1151787B1 (de) 2006-07-19

Family

ID=26148536

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01117775A Expired - Lifetime EP1151787B1 (de) 1996-11-01 1997-10-31 Bildung einer Lösung aus Fluiden mit niedriger Mischbarkeit und grossem Unterschied in der Viskosität

Country Status (1)

Country Link
EP (1) EP1151787B1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1405896A1 (de) * 2002-10-01 2004-04-07 Clariant GmbH Verfahren zur Herstellung von Additivmischungen für Mineralöle und Mineralöldestillate
CN116791217A (zh) * 2023-08-21 2023-09-22 江苏青昀新材料有限公司 一种闪蒸纺丝用的双螺杆进料系统

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3941535A (en) * 1974-10-01 1976-03-02 Street Louis F Extrusion device
EP0285670A1 (de) * 1986-10-13 1988-10-12 Asahi Kasei Kogyo Kabushiki Kaisha Vernetzte polyäthylenfaser hoher dichte und nichtgewobene gewebe daraus sowie deren herstellung
US5215764A (en) * 1991-06-10 1993-06-01 Westland Corporation Extruder mixing screw
EP0664151A1 (de) * 1994-01-21 1995-07-26 Sealex Incorporated Dynamischer In-Line Mischer mit Faltelementen und perforierten Platten

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3941535A (en) * 1974-10-01 1976-03-02 Street Louis F Extrusion device
EP0285670A1 (de) * 1986-10-13 1988-10-12 Asahi Kasei Kogyo Kabushiki Kaisha Vernetzte polyäthylenfaser hoher dichte und nichtgewobene gewebe daraus sowie deren herstellung
US5215764A (en) * 1991-06-10 1993-06-01 Westland Corporation Extruder mixing screw
EP0664151A1 (de) * 1994-01-21 1995-07-26 Sealex Incorporated Dynamischer In-Line Mischer mit Faltelementen und perforierten Platten

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1405896A1 (de) * 2002-10-01 2004-04-07 Clariant GmbH Verfahren zur Herstellung von Additivmischungen für Mineralöle und Mineralöldestillate
DE10245737B4 (de) * 2002-10-01 2005-06-09 Clariant Gmbh Verfahren zur Herstellung von Additivmischungen für Mineralöle und Mineralöldestillate
US7872061B2 (en) 2002-10-01 2011-01-18 Clariant Produkte (Deutschland) Gmbh Preparation of additive mixtures for mineral oils and mineral oil distillates
DE10245737C5 (de) * 2002-10-01 2011-12-08 Clariant Produkte (Deutschland) Gmbh Verfahren zur Herstellung von Additivmischungen für Mineralöle und Mineralöldestillate
CN116791217A (zh) * 2023-08-21 2023-09-22 江苏青昀新材料有限公司 一种闪蒸纺丝用的双螺杆进料系统
CN116791217B (zh) * 2023-08-21 2023-11-21 江苏青昀新材料有限公司 一种闪蒸纺丝用的双螺杆进料系统

Also Published As

Publication number Publication date
EP1151787A3 (de) 2002-01-30
EP1151787B1 (de) 2006-07-19

Similar Documents

Publication Publication Date Title
EP0935496B1 (de) Bildung einer lösung aus fluiden mit niedriger mischbarkeit und grossem unterschied in der viskosität
US5816700A (en) Process and apparatus for mechanically mixing polymers and lower viscosity fluids
US6027241A (en) Multi viscosity mixing apparatus
EP1392418B1 (de) Verfahren zum mischen von flüssigkeiten oder gasen mit stark unterschiedlicher viskosität
CN1326602C (zh) 一种连续动态混合至少两种流体的方法及微量混合器
KR20080046280A (ko) 액체 착색제 혼합 장치, 방법 및 액체 착색제를 사용한플라스틱 착색 방법
EP1792643B1 (de) Grossvolumiger Reaktor beziehungsweise Dünnschichtverdampfer mit einem Vormischaggregat
WO1994011096A1 (en) Fluid mixing apparatus
US4082488A (en) Apparatus for the extrusion of temperature sensitive thermoplastics
EP1151787B1 (de) Bildung einer Lösung aus Fluiden mit niedriger Mischbarkeit und grossem Unterschied in der Viskosität
CN115595675A (zh) 闪纺溶液混合装置及闪纺设备
US4444507A (en) Apparatus and method for melting and conveying plasticated material
US2169339A (en) Mill for dispersion and mixing
JPS5836626A (ja) 分散混合装置
KR20010015786A (ko) 중합체융해물을 믹싱하고 운반하는 장치
WO2002018282A2 (en) Process and pump for homogenizing molten glass
US3675903A (en) Mixing device
US3525504A (en) Additive mixer
US3127152A (en) Counter-rotation continuous shear mixer
JP3578505B2 (ja) インライン動的連続混合装置
JP2542332B2 (ja) 回転混合器
US3008696A (en) Means for blending viscous liquids
US2961223A (en) Additive injecting and blending apparatus for filament spinning
DE2216444A1 (de) Mischvorrichtung zur herstellung einer homogenen mischung aus mehreren stoffkomponenten
SU242366A1 (de)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AC Divisional application: reference to earlier application

Ref document number: 935496

Country of ref document: EP

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE ES FR GB IT

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE ES FR GB IT

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: E.I. DU PONT DE NEMOURS AND COMPANY

17P Request for examination filed

Effective date: 20020308

AKX Designation fees paid

Free format text: DE ES FR GB IT

17Q First examination report despatched

Effective date: 20040617

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AC Divisional application: reference to earlier application

Ref document number: 0935496

Country of ref document: EP

Kind code of ref document: P

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE ES FR GB IT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRE;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.SCRIBED TIME-LIMIT

Effective date: 20060719

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 69736361

Country of ref document: DE

Date of ref document: 20060831

Kind code of ref document: P

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20061030

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20070420

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20071025

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20071009

Year of fee payment: 11

Ref country code: GB

Payment date: 20071031

Year of fee payment: 11

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20081031

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20090630

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090501

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20081031

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20081031