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
  • 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
  • B29C48/252—Drive or actuation means; Transmission means; Screw supporting means
• • 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
  • B29C48/001—Combinations of extrusion moulding with other shaping operations
  • B29C48/0021—Combinations of extrusion moulding with other shaping operations combined with joining, lining or laminating
• • 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
  • B29C48/07—Flat, e.g. panels
  • B29C48/08—Flat, e.g. panels flexible, e.g. films
• • 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
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
  • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
  • B29C55/06—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
• • 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
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
  • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
  • B29C55/08—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique transverse to the direction of feed
• • 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
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
  • B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
  • B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
• • 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
  • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
  • B29K2023/04—Polymers of ethylene
  • B29K2023/06—PE, i.e. polyethylene
• • 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
  • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
  • B29K2023/10—Polymers of propylene
  • B29K2023/12—PP, i.e. polypropylene
• • 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
  • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
• • 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
  • B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
  • B29K2067/04—Polyesters derived from hydroxycarboxylic acids
  • B29K2067/046—PLA, i.e. polylactic acid or polylactide
• • 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
  • B29K2069/00—Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• • 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
  • B29K2077/00—Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• • 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
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/25—Solid
  • B29K2105/253—Preform
  • B29K2105/256—Sheets, plates, blanks or films

Definitions

• the present invention relates to a process for the production of films from thermoplastic materials.
• thermoplastic materials have found widespread use for a wide variety of applications.
• the biaxially stretched polypropylene films can no longer be dispensed with today in the field of food packaging.
• the polymers of the individual layers are first melted in an extruder and the melts are extruded through a flat die.
• the shaped melt film is cooled on a take-off roll, solidified and then optionally biaxially stretched.
• the stretching in the longitudinal direction by rolls running at different speeds is generally carried out first.
• stenter transverse stretching frame
• the orientation in the transverse direction and finally the fixation and winding.
• the biaxial stretching can also take place simultaneously. Biaxial stretching ensures important performance characteristics such as mechanical strength, stiffness, transparency and a uniform thickness profile.
• the foil may only be subjected to mechanical stress in these stretching processes to the extent that it can withstand these forces and must not tear off during this process. Demolition always results in disruption of the production process, long downtime and major economic damage.
• the web must be constantly maintained by a certain tension in the longitudinal and transverse directions to keep the running web smooth and wrinkle-free. It is just as important that these tensile stresses do not exceed the mechanical strength of the film, otherwise it will break again.
• the film may have locally limited mechanical weaknesses due to an uneven thickness profile. Contaminations of the raw material, e.g. Speckling can create such vulnerabilities, uneven heating can have similar effects.
• Speckling can create such vulnerabilities
• uneven heating can have similar effects.
• it often proves to be very difficult to assign an outline of a clear cause and to eliminate this cause reliably. Targeted investigations in this regard are difficult because it is always the goal to avoid demolitions on the production facilities. The repetition of faulty situations is too costly. So it often remains with unclear foil breaks, which are accepted as a statistical phenomenon, without the causes are ever determined.
• the present invention is based on the object to reduce the number of breaks in the production of a film web, ie to provide a method with which a film can be produced process safe and without or with the lowest possible number of breaks per unit time ,
• the method is intended to ensure that the material web can be guided and transported without wrinkles and distortion and, if appropriate, can be stretched sufficiently high in the longitudinal and transverse directions.
• the process should be used equally successfully at different running speeds of the material web, as well as for different materials.
• This object is achieved by a method for the production of films of thermoplastic materials, in which one or more driven / s element / s is connected to a first power source for power supply /, characterized in that by means of a second power source, an uninterruptible power supply (UPS ) of these driven elements is ensured.
• UPS uninterruptible power supply
• mains voltage and mains frequency are subject to permanent fluctuations due to the fluctuating power consumption of consumers on the one hand, but also due to network disturbances on the other hand.
• Network disturbances can be caused both by unwanted reactions of the consumers of the current and by accidental events such as e.g. weather-related disturbances are caused.
• short circuits caused by lightning strikes during a thunderstorm or by construction machinery in earthworks but also the switching on and off of larger electric motors or electric arc furnaces, and even the switching on and off of consumer loads and power plant units cause voltage drops or voltage boosts.
• Such induced voltage drops are referred to as short breaks in a short period of time, which generally, e.g. with bulbs, go unnoticed.
• the breaks during the short breaks are most likely caused indirectly by the different inertia of the various components.
• the extrusion of the polymer melts is influenced by the short interruptions.
• the individual components of the film are melted and mixed via a screw, which simultaneously promotes the melt along the extruder.
• the worm is thus also a driven element in the sense of the present invention.
• Short-term interruptions in the extrusion area for example, have an effect on pressure fluctuations, which can impair the thickness profile and thus indirectly lead to weak spots where breaks occur.
• a UPS is within the meaning of the present invention, a device according to EN-50091-1, which comprises an energy storage device, generally in conjunction with power converters and electronic control and regulation that compensates for these fluctuations in variations in the voltage or the frequency of the primary power source until the fault is over so that a steady supply of the load is ensured.
• Films are in the context of the present invention sheet-like material webs that are flexible and generally have a thickness of less than 1000 ⁇ m. Films can be constructed as single-layered or multi-layered. Films in the context of the present invention comprise undrawn films, monoaxially oriented films and biaxially oriented films.
• thermoplastics are polymers which become soft and plastically deformable at elevated temperatures, for example polyesters, polycarbonate, polyamides, polyolefins, such as polyethylenes, polypropylenes, cycloolefin polymers, polylactic acid, etc.
• the longitudinal direction is the direction in which the material web runs; This direction is also referred to as the machine direction.
• the transverse direction in the sense of the present invention is that direction which is at an angle of 90 °, i. runs transversely to the machine direction.
• the biaxial stretching (orientation) can be carried out simultaneously or sequentially.
• stretching is generally first longitudinal (in the machine direction) and then transverse (perpendicular to the machine direction).
• the polymers of the individual layers are compressed and liquefied in an extruder, wherein any additives added may already be present in the polymer or in the polymer mixture.
• the melts are then pressed and shaped simultaneously through a flat die (slot die), and the monolayer or multilayer film is peeled off on one or more take-off rolls, thereby cooling and solidifying.
• the temperature of the take-off rolls is in a range of 10 to 120 0 C, preferably 20 to 80 0 C.
• the prefilm is stretched longitudinally with the aid of two rolls, which run in different directions according to the desired draw ratio.
• the longitudinal aspect ratios for polypropylene films are in the range of 3 to 8, the temperature is 80 to 150 ° C.
• Both drafting rollers have their own drive, which controls the peripheral speed of each roller and thus the stretching factor.
• the transverse stretching is carried out with the help of a clip frame, for polypropylene films at a temperature of 120 to 180 0 C and a transverse stretch ratio of 5 to 10.
• the film web is heated in the heating fields to the required transverse stretching temperature, for example by hot air from nozzle boxes , which are mounted below and above the film web or by a convection heating or IR emitter.
• the film When entering the heating fields, the film is grasped on both edges by the clips of a driven circumferential clip chain.
• the clips guide the film through the entire cross-stretch frame. After passing through the heating fields, the film enters the drafting field. Due to the divergent guidance of the clip chain, the film is pulled continuously on the way through the drafting field in the width until it has reached the intended width at the end.
• the temperature can be varied by means of appropriate devices in the running direction. After stretching in the drawing field, the film passes through the fixation. In this area, the film is held by means of the clips at a constant width and at a constant or decreasing temperature in the running direction in order to fix the orientation achieved by transverse stretching.
• convergence can also be performed in the fixation in order to partially reduce the stresses introduced by orientation.
• the clips open and the film is continued on rotating rollers, while cooled to room temperature, optionally plasma-treated on the surface to be treated, corona or flame-treated and finally wound up.
• biaxially oriented films can be prepared by the simultaneous stretching process.
• the film is stretched simultaneously in the longitudinal and transverse directions after cooling to the prefilm by suitable devices.
• suitable devices for carrying out the method are known in the art
• LISIM or MESIM method mechanical simultaneous stretching
• LISIM methods are described in detail in EP 1 112 167 and EP 0 785 858, to which express reference is hereby made.
• An MESIM method is described in US 2006/0115548, to which reference is also expressly made.
• the simultaneous stretching takes place according to a continuous simultaneous stretching method.
• the film is in this case in a similar to the transverse stretching frame, transported drawing furnace with a transport system that operates according to the WEL ches LISIM ® process.
• the film edges are also detected by clips, which, however, are driven individually by means of a linear motor.
• Individual clips for example, every third, are equipped with permanent magnets and also serve as a secondary part of a linear motor drive. Over almost the entire circulating transport path, the primary parts of the linear motor drive are arranged parallel to the guide rail.
• the non-driven clips serve only to absorb film forces across the direction of travel and to maintain the tension between the breakpoints.
• the prefilm passes through, in an analogous manner, a heating zone in which the guide rails of the clips run substantially parallel.
• the prefilm is heated by a suitable heater from the inlet temperature to the stretching temperature.
• the simultaneous stretching process begins by accelerating the mutually independent clip-on carriages in the film direction and thus separating them, ie increasing their distance from one another. In this way, the film is stretched in length.
• a transverse extension is superimposed on this process, specifically in that the guide rails diverge in the area of the claw acceleration.
• the film is fixed as known from the sequential stretching in principle.
• the film is optionally in the longitudinal or transverse direction controlled slightly relaxed in the clamped state. Particularly advantageous may be the simultaneous relaxation in the longitudinal and transverse directions.
• the clip-on wagons are decelerated, reducing their distance from each other.
• the guide rails of the transport system are easily converged.
• the simultaneous stretching is carried out according to a principle equivalent to the LISIM method.
• the film is also transported here in a stretching oven with a transport system of clips on guide rails.
• the scissors joint By the scissors joint, the distance between the clips can be varied. In which the scissors joint is pulled apart, the distance of the clips to each other increases. Conversely, the distance is reduced when moving the joint.
• the two guide rails of the respective pair of rails are arranged converging, whereby the scissors joint is pulled apart and accelerate the clips in the running direction of the film and increase their distances from each other.
• the film is stretched in length.
• a simultaneous transverse extension takes place by the divergent arrangement of the rail pairs at each edge of the film, a simultaneous transverse extension.
• the blown film process is known per se in the art.
• the melt is extruded through a ring die to a hose which is squeezed at the lower end by rolling and pulled in the length.
• the compressed air inflates the tube to a certain extent, whereby a biaxial stretching takes place in principle simultaneously.
• All these processes have in common that are driven elements for the extrusion of the melts, for guiding and possibly stretching the film and supplied by a primary power source.
• Driven elements are, for example, extrusion screws, all driven rollers over which the films are guided, possibly stretched and wound, the clip chain in the sequential drawing or the linear motor-equipped clips in the LISIM method and the scissors link in the MESIM method.
• These driven devices are collectively referred to as elements below.
• a UPS that these elements are supplied trouble-free for the extrusion of the melts and for guiding, stretching or winding a film web.
• the UPS used according to the invention is designed such that undervoltages, overvoltages, frequency changes and harmonics of the primary energy source are compensated or bridged.
• the UPS includes an energy storage, power converters and electronic control and regulation.
• the UPS used should provide a peak power of up to 10MW, with continuous power much lower.
• the maximum bridging time depends on the capacity of the energy storage and the currently required power and can be between a few 100ms and several minutes depending on the requirement.
• capacitors in the form of double-layer capacitors so-called supercaps.
• foil breaks or quality variations are not only caused by prolonged disturbances in the power grid, but many of the previously considered as statistical errors breaks can be explained by the short-term interruptions of the primary energy source, in which the disturbances less than 1s, For example, 10 to 500ms persist. The disturbances are generally not perceived by other consumers and usually do not cause any disturbing effects.
• UPS are in the context of the present invention, only those of the category VFI particularly suitable.
• VFD, VFI and VI have the meaning defined in the product standard IEC 62040-3.
• VFI Voltage and Frequency Independent
• the input is routed directly to a rectifier that feeds the second energy source.
• the output is supplied exclusively by an inverter which, in normal operation, ie when the mains voltage at the UPS input is present, obtains the necessary energy via the rectifier (GR) and is supplied with power via the second energy source.
• GR rectifier
• the UPS is installed between the US side transformer outlet and the load terminals (L1, L2, L3) (see Fig. 1).
• VFI UPSs have a so-called bypass circuit, which is connected in parallel with the rectifier / inverter combination. If there is an overload on the UPS output or if an internal error occurs in the GR / WR branch, the connected consumer is switched to this bypass branch "without interruption" and thus supplied further.
• the energy storage is installed on the DC bus of the UPS and supports it when the voltage at the input fails.
• VFI UPS not only protect against the consequences of power failure, undervoltage and overvoltage, but also against fluctuations in the frequency and before harmonics. They are also referred to by the terms “online”, “double conversion”, “continuous operation” or “double conversion”.
• the consumers such as DC drives, require a DC system with variable output voltage, the input rectifier, the DC link and the energy storage of the UPS are required.
• the variable DC voltage is then generated via DC / DC converter from the DC voltage of the DC link (Fig. 3).
• the energy store can be connected either directly (FIG. 3 and FIG. 4) or via a DC / DC converter (FIG. 5) to the voltage intermediate circuit. All the circuit variants have in common that the energy is buffered via an intermediate circuit capacitor.
• the capacitance of this capacitor is on the order of a few mF (0.1 - 1OmF) and is not sufficient to bridge short interruptions of up to 3s. This energy storage must be used with a higher energy density.
• accumulators are generally suitable as energy storage and have a relatively high energy density.
• their power density is not sufficient for the application [Bine Informationsdienst Zarinfo 11/03] This means that for the high power application very many accumulator cells have to be used which consume a lot of space at the same time. Often, this space is then not available in a system for film production.
• a solution with accumulators also provides an amount of energy that could supply the system for more than 10 minutes. However, since most disturbances in the power grid are shorter than 3s, the amount of energy provided is much too large.
• a solution with a capacitor bank with double-layer capacitors requires significantly less space for the same power, the volume is about 100 times smaller than that of a comparable accumulator. Since the energy density of such double-layer capacitors is about 100 times smaller than that of accumulators, only one time can be given for the same volume be bridged by about 10s. This is exactly the time required to bridge short breaks.
• the double-layer capacitor has an approximately 3 times longer life of about 10 years compared to the accumulator. Its state of aging, and therefore the time to replace the capacitors, can also be determined by the capacitance.
• the Doppel fürkondensa- tor is the preferred solution to overcome the problems caused by short breaks in systems for film production.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

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• 2008
  • 2008-11-15 RU RU2010126081/05A patent/RU2486057C2/ru not_active IP Right Cessation
  • 2008-11-15 BR BRPI0819728A patent/BRPI0819728B1/pt not_active IP Right Cessation
  • 2008-11-15 WO PCT/EP2008/009693 patent/WO2009068200A2/de active Application Filing
  • 2008-11-15 CN CN200880118001.9A patent/CN101878102B/zh not_active Expired - Fee Related
• 2010
  • 2010-05-12 ZA ZA2010/03340A patent/ZA201003340B/en unknown

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