DE102006047942B3 - Reactor for batchwise polycondensation of polymers, comprises a horizontal cylindrical casing containing a hollow rotor with film-forming elements and scrapers, in the form of a heatable, evacuatable autoclave - Google Patents

Abstract

A reactor for the batchwise polycondensation of polymers comprises a horizontal cylindrical housing (4) with inlet and outlet (2, 3) and a hollow cylindrical rotor (5) supported by stub axles (projecting through the reactor walls) and a bearing system, and with annular film-forming elements (6) on the rotor (5) and scrapers (7) extending into the housing (4) between the elements (6) as far as the rotor (5), the reactor (1) being in the form of a heatable, evacuatable and pressure-tight autoclave. An independent claim is included for a method for the batchwise polycondensation of oligomers/monomers using a reactor as described above.

Description

This The invention describes an apparatus and a process for the batchwise polycondensation of polymers.

Conventional typical devices are generally stirred autoclaves, which differ in their shape, in particular in the L / D ratio and in the design of the stirrer, but essentially from a stationary container with a conical, curved or spherical bottom and a centrally inserted from above agitator consist with drive. The filling is done by pumping or pushing with the aid of an inert gas usually through a tube arranged in the lid. The stirrer can be used as anchor stirrer, screw stirrer (one or two coils, such as in US 5,727,876 disclosed) or as a combined stirrer with helix and upwardly conveying screw with and without heated central tubes. Depending on the product, an adaptation to the best possible type can be selected or designed by a specialist. For all types, they do not provide sufficient surface area for the induced, rapid diffusion of solvents and by-products in relation to the polymer composition. In large batches, the ratio becomes so poor that residence time and process temperatures become unbearably high in terms of cost-effectiveness and quality, ie there is an approach limit resulting from these boundary conditions, which is about 30 to 40 t / d, depending on the product , However, economic plant sizes for continuous operation are higher by a factor of 5 to 10.

in this respect is a gap especially in the field of highly flexible batchwise polycondensation, in particular specialized products available, mostly in smaller lots are in demand from the market.

Another variant is the addition of a precondensation reactor so that the process would consist of three steps (eg FR 1.386.676 ). Such arrangements have the advantage that existing 2-reactor systems can be upgraded to get higher production output, thus shortening the cycle time. However, the complexity of this process is similar to that of a continuous process, some of which already has two reactors today, such as in DE 101 55 419 A1 and benefits from greater product equivalency and lower energy consumption.

It It is also known that in conventional autoclaves the initial and final product during the dispensing a viscosity spectrum that gets through the length the process is determined. This is due to chain breaks, caused by thermal stress of the polymer after completion Polycondensation. This is usually the applied process vacuum broken by means of nitrogen. This is a costly process because it generates high purity nitrogen whose oxygen content must be only a few ppm the oxidative damage of the polymer to prevent.

From the DE 100 01 477 B4 a stirring disk reactor is known, which has a frusto-conical housing and are moved on a central axis elements that pass through the oligomer mixture. Other hollow rotor reactors are from the documents CS 127 858 . DE 44 47 421 or CAPLUS 1097: 149825, AB.

Usual procedures For the preparation of polymers usually consist of two consecutively switched autoclave, wherein in the first either a Um- or an esterification expires or an evaporation (preconcentration) is made. The resulting Monomer or oligomer then becomes steady in the second autoclave lowered pressure into the high vacuum range and elevated temperature to the long-chain polymer with the solvent or a reaction component educated. In this case, the melt viscosity initially rises slowly towards the end the process is exponential. Typically, the number is the monomer repeating units at the end at max. 135. The upper one Boundary is determined by the discharge time, which is far less than 30 minutes, the nitrogen pressure (thus consumption), the stirrer and the dimensioning of the discharge pipe, the subsequent granulation fed.

outgoing It is therefore an object of the present invention to a reactor device for the to provide batchwise polycondensation of polymers which a higher one Production rate of polymers with improved quality and economy allows. It is a further object of the present invention to provide a process for polycondensation of polymers using the reactor apparatus mentioned above specify.

These The object is achieved by the reactor apparatus having the features of Claim 1 solved. With Claim 28 is a method for batch polycondensation provided. The respective dependent claims advantageous developments.

According to the invention, a reactor apparatus for the batchwise polycondensation of polymers is provided, comprising a hori having at least one inlet and outlet zontal arranged cylindrical reactor housing arranged rotating hollow cylindrical rotor, which is mounted horizontally via bearing devices by means of beyond the end walls of the reactor housing stub shaft assembly, as well as arranged on the hollow cylindrical rotor annular film forming elements and scrapers, which protrude between the annular film forming elements in the interior of the reactor housing to the hollow cylinder rotor and the reactor device is designed as a heatable evacuated and pressure-resistant autoclave.

By the reactor device is the production of polymers with several, Superior to the state of the art Benefits connected. On the one hand, the cycle time of an approach, in conventional 3 to 4 hours, at times less than 3 hours, for example 1.5 to 2 hours, shortened. By the guaranteed intensive mixing of the reaction mixture, it comes to a extremely surface-active Reaction. this makes possible a larger dimensioning and thus larger approaches, what naturally with economic Benefits connected.

Sealing and storage of the basket shaft stub can eg as in DE 44 47 421 or DE 44 47 422 A1 be performed.

When Rotary drive can All types of geared motors with speed control can be used.

there it is advantageous if longitudinal at the bottom of the cylindrical Reactor housing a Product collecting cone is arranged, which flattened parallel in the longitudinal direction is. The width is viscosity dependent and is at least 120 mm. It is also advantageous if the cylindrical reactor housing in the area the base of the product collection cone has breakthroughs that are at least a free area of 25%. The cone angle in the longitudinal direction can be between 60 ° and 140 ° vary and be different depending on the product.

In A further advantageous embodiment is on the cylindrical reactor housing at the top a product feed nozzle arranged. This product feeder may also have a flange for connection to the product conduit exhibit.

to even distribution of the supplied Product throughout the reactor, it is advantageous if in the upper Area zenith of the cylindrical reactor housing below of the product supply nozzle a product distribution device is provided. The product distribution device can, for example, as a slotted pipe over the entire length of Reactor or be executed on each side as a slot nozzle.

Farther is it cheap if at least in the upper region of the cylindrical reactor housing a vapor and / or exhaust port is provided. About these vapors and / or Exhaust pipe can during Polycondensation a discharge resulting gaseous Reaction by-products take place. In an advantageous embodiment is the vapor and / or exhaust port while not exactly vertical to the reactor device attached but horizontally or tangentially with a slope of up to 30 ° arranged horizontally. Exemplary embodiments provide that this nozzle offset with an inclination of, for example, 10 ° or 20 ° is arranged from the zenith and has such a diameter, that is a maximum velocity of a gas flowing through 40 m / s does not exceed. Of course, about this Nozzles can also be applied to the reactor apparatus.

As well is it cheap when the hollow cylinder rotor is arranged eccentrically in the cylindrical reactor housing is. According to the invention is included understood that the horizontally oriented suspension axis of the hollow cylinder rotor not with the horizontal main axis of the Reactor housing coincides.

Farther it is advantageous if the horizontal longitudinal axis of the hollow cylinder rotor in the vertical direction to the product collection cone, offset to cylindrical Reactor housing, is arranged. Thus, it is thus provided that the horizontal longitudinal axis of the hollow cylinder rotor with respect to the horizontal longitudinal axis of the cylindrical one reactor housing is offset down.

According to the invention of Hollow cylinder rotor thereby both as a closed frame and / or as Korblochzarge be formed. In the case of a Korblochzarge can the size of the holes vary as you like. The holes can also to reinforced Homogenization of the reaction mixture contribute.

there It is advantageous if the Rotorzarge over the entire length of Extends reactor, so almost reaches to the end ceiling of the reactor housing, however, the end covers are not touched. typically, is the rotor frame by about 20 to 40 mm shorter than the reactor internal length.

In order to ensure thorough mixing of the reaction mixture, circumferential resilient scrapers are arranged between the end caps and the rotor frame. The scrapers can for example, be performed segmented.

A sees further advantageous embodiment before that the space between the end covers and the rotor frame a feeder for inert gas having. About that For example, the reaction space can be rinsed, or it can be increased pressure be constructed for product discharge.

As well It is advantageous if the ratio of Korbrührerdurchmessers to the container diameter of the reactor is 0.98 to 0.82.

In In another advantageous embodiment, the ratio of Rotor rim diameter to the reactor diameter between 0.5 and 0.8.

Regarding the outer dimensions of the reactor, it is convenient if the ratio the length of the Reactor to the reactor diameter between 0.5 to 1.5.

Either Rotor frame as well as product collection cone can be tempered, i. heated but also cool be. This can be done, for example, by having them Elements limiting wall is designed double-walled. The double coat of the Heatable elements can be provided for both liquid and vapor heat transfer medium be, being the liquid Because of heat transfer The possibility of cooling is given priority. The heat carrier for the heated Basket frame is over a rotary union centrally supplied and removed by one of the two bearing shafts.

In a further preferred embodiment with respect to the annular film-forming elements this by a tubular Wreath and a spanned between the tubular rim and the rotor surface formed net-like metallic tube structure. For example the scrapers are arranged in 3-square shape, which ensure that no polymer closure forms between the tube rings and at the same time the basket frame, which can optionally also be heated, from upflowing Polymer is purified. This results in a thin-film effect, which greatly contributes to the accelerated reaction by shortening the Contributes diffusion pathways. The pipe rings can while perpendicular to the Rührkorbzarge stand and are made of tubes of size from 12 to 30 mm. The support tubes can in the process of being formed as involutes, between the pipes as well are stretched so that triangular or diamond-shaped openings for film formation arise.

erreichen.In addition to the described pipe rings, the thin and continuously renewed polymer layer produced by wipers on the heated mixing basket contributes significantly to the diffusion of the solvent. In principle, a recumbent autoclave of about the same batch size compared to a stationary already has the advantage of a larger evaporation surface, assuming 30 degree of filling and no agitator, which is 1.5 to 2 times. The standard agitators allow mass-referenced new surface rates, depending on viscosity, from 50 to 150

to reach.

erreicht. Die beheizte und abgestreitte Korbzarge verbessert diesen Wert nochmals auf 500 bis 600,

so dass man im Vergleich zum Standard-Rührwerk die Zeit zur Polykondensation um den Faktor 3-4 verkürzen kann.Values of 300 to 400 are already found in a tubular basket with a perforated basket frame

reached. The heated and separated basket frame improves this value again to 500 to 600,

so you can shorten the time for polycondensation by a factor of 3-4 compared to the standard agitator.

advantageously, is the ratio of the pipe ring diameter to the stirring basket diameter 1.2 to 2.5 to 1.

Farther is it cheap if the remaining webs of the basket hole frame in the inner area with Semicircular and / or Triangular profiles are dressed. This will also improve Homogenization of the reaction mixture achieved.

In In another advantageous embodiment, the scrapers triangular and preferably carried out so and adjusted so that the optional heated / cooled rotor frame as a thin film film generator is working. In addition to the rotor frame, the product collection cone can also be used heated and / or cooled and preferably ends directly in a product take-off flange.

• a) Austrag des Polymeransatzes nach Beendigung der Polykondensation unter atmosphärischem Druck,
• b) Rezirkulation des Oligomers während der Polykondensationszeit über die im Zenith der Behälterzarge angeordnete schlitzförmige Verteilung.

In a further favorable embodiment, the product removal flange is connected directly to a discharge and / or recirculation pump whose inlet opening is preferably 1.5 to 3 times the total tooth cross-section of the pump. The discharge pump serves two purposes:

• a) discharge of the polymer mixture after completion of the polycondensation under atmospheric pressure,
• b) recirculation of the oligomer during the polycondensation over the arranged in the zenith of the container frame slot-shaped distribution.

there is preferably connected to the recirculation pump a circulation line, which is connected to the inlet of the reactor device.

advantageously, the circulation line has a filter device. Farther is it cheap if the circulation additionally an online viscosity measuring device which gives a precise Control and monitoring a variety of parameters is possible. Of course, with this reactor / autoclave also regarding the use of co-monomers, stabilizers, catalysts and other additives have no limits. These Kings can ever according to desired Product properties selected even if they change the reaction speed and the sequences for this purpose changed Need to become.

According to the invention as well a process for the batchwise polycondensation of oligomers / monomers provided, characterized in that a, as in Previously described reactor device is used.

by virtue of this cheap Surface creation rates is also a lowering of the reaction temperature by up to 15 ° C over the usual Method possible whereby the production of highly viscous material due to the reduced thermal damage only makes sense.

Preferably At the beginning of the polycondensation, the reactor apparatus is up to a filling volume filled from 15 to 40% and then in the course of polycondensation, depending on the product viscosity, the oligomer in the ratio of 0.5 to 5, based on the filled dimensions, on the product distribution device recirculated.

A particularly advantageous property of the method is that the Polycondensation can be carried out up to 205 MWE (monomer repeating units) can.

advantageously, is the procedure so conducted that with a heated, closed rotor frame and / or unheated Basket hole frame at temperatures up to 350 ° C and vacuums up to 0.1 mbar is worked.

Cheap is it, if the turning frame of the basket motor depending on the power consumption of Basket or the viscosity of the polymer / oligomer selected or regulated.

erreicht werden und der beheizte, abgestreifte Korbrotor hierzu einen Beitrag von 30 bis 50 leistet.Furthermore, it is advantageous if the mass-related surface recharge rates of 300 to 600

be achieved and made the heated, stripped basket rotor this contribution of 30 to 50.

In In another advantageous variant of the method, the reaction time, ie the polycondensation time, in a range of 30 to 120 Minutes dialed.

advantageously, the heating / cooling takes place of housing and rotor by organic heat transfer medium in liquid or vaporous form.

As well is it cheap if the melt during the product discharge is still kept under a negative pressure.

to Maintaining an inert atmosphere in the reactor is at completion the product discharged the reactor with atmospheric inert gas.

Especially it is preferred if the reaction at 5 to 20 ° C above the melting point of the polymer is carried out.

Example of process control

The Oligomer is removed from a 1st autoclave within 10 min over the Rezirkulationsleitung in which he inventive reactor promoted until a filling volume from about 20% to 30%. The stirrer runs with max. speed from about 10 rpm. It becomes dependent in the course of polycondensation from the product viscosity constantly tracked in the speed to maximize its efficiency. At the end, the speed is only about 0.5 to 1 rpm. After a set program is the pressure up to the high vacuum range, which can be up to 0.2 mbar can, lowered. At the same time, the heater provides heat transfer of the jacket and the basket frame for a Hold or a temperature increase of the polymer. This can also program conducted respectively. In the final stage of the process can also - depending on Product - one Cooling the Mantels or the stirring basket tongs be required to absorb the introduced mechanical energy as an increase the polymer temperature affects, dissipate. The training of the stirring basket as a closed, heated cylinder has this due to its huge Heat exchange surface and Mass transfer area a significant advantage over conventional ones Systems by the temperature difference between heat carrier and Product can be kept very small and thus the thermal Strain on the polymer and therefore the quality can be significantly improved can.

To Achieve the desired Viscosity of Product will recirculate before the start of the vacuum phase was started, stopped and the discharge is over Reusable valve initiated. The vacuum is controlled so that the viscosity while the discharge process, the maximum 20 min, remains constant.

During the Austragens can the basket stirrer be stopped or run at minimum speed by one maximum homogeneity of the polymer to obtain. Towards the end of the discharge, the vacuum is replaced by inert gas broken, leaving the autoclave back under atmospheric pressure stands.

Based the following figures, the inventive subject matter is explained in more detail, without the invention to the special embodiment shown there restrict to want.

It demonstrate

1 a sectional view perpendicular to the longitudinal axis of the reactor device according to the invention,

2 a sectional view along the longitudinal axis of the reactor device.

in the The following will be referred to the two following Characters.

The reactor device 1 is through a housing 4 limited, which can be designed double-walled. The double-walled housing 4 can thus be filled with a suitable heat transfer medium, which has a suitable pumping device in the double-walled housing 4 can be brought to circulation. This allows a temperature of the in the reactor 1 take place reaction mixture. Above, attached approximately in the middle, is the inlet 2 the reactor device 1 , the outlet 3 to discharge the reaction mixture is below. The hollow cylinder rotor 5 is rotatable in the reactor housing 4 stored and is eg driven by a geared motor with speed control, which can be mounted externally. Out 2 It can be seen that the axis of rotation of the circular hollow cylinder rotor 5 not with the longitudinal axis of the likewise circular shaped reactor housing 4 coincides, but that the longitudinal axis of the hollow cylinder rotor 5 with respect to the axis of the housing 4 is offset down. The hollow cylinder rotor 5 can be formed vollmantelig, or be provided with holes, so that it is designed as a basket hole frame. The wall of the hollow cylinder rotor 5 is the same as that of the reactor housing 4 formed double-walled, so that in an analogous manner, a heating of the rotor 5 is possible. At the hollow cylinder rotor 5 are the annular film-forming elements 6 and scrapers 7 arranged, which allow homogenization of the reaction mixture. Here are the film-forming elements 6 formed triangular, so that the most efficient film formation is guaranteed. The annular film-forming elements 6 are doing a tubular wreath 12 arranged. By stripping the film formed by the Abstreifungselement 7 Furthermore, an improvement of the mixing is ensured. The bottom of the reactor 1 is there as a product collection cone 8th trained, which allows a collection of the product. The product collection cone 8th can also be double-walled, so that a temperature control is also possible. The product collection cone 8th is doing by a flange 14 limited. Directly to the flange 14 is the product discharge pump 15 attached, to which a valve can be attached, via which the final discharge of the product, for example, can be done to a granular device, but also a return of the product in the reactor device 1 over to the pump 15 attached line 16 , For intermediate cleaning of the product, for example, a filter 17 be installed, to control the process or to verify the material properties achieved an online viscometer 18 , The administration 16 in turn ends at the top of the reactor device 1, in the inlet 2 for example, as a product feed nozzle 9 is formed with associated flange. In order to distribute the product as efficiently as possible when it is introduced into the reactor 1 to ensure is a product distribution device 10 intended.

Claims (38)

Reactor device ( 1 ) for the batchwise polycondensation of polymers comprising one, in at least one inlet and outlet ( 2 . 3 ) having horizontally arranged cylindrical reactor housing ( 4 ) arranged rotating hollow cylindrical rotor ( 5 ), which via bearing devices by means of the end walls of the reactor housing ( 4 ) extending stub shaft arrangement is mounted horizontally, as well as on the hollow cylinder rotor ( 5 ) arranged annular film-forming elements ( 6 ) and scrapers ( 7 ) between the annular film-forming elements ( 6 ) in the interior of the reactor housing ( 4 ) to the hollow cylinder rotor ( 5 protrude), wherein the reactor device ( 1 ) is designed as a heatable, evacuated and pressure-resistant autoclave. Reactor device according to claim 1, characterized in that the cylindrical reactor housing ( 4 ) at the bottom of a product collection cone ( 8th ) having. Reactor device according to claim 2, characterized characterized in that the product collection cone ( 8th ) is flattened parallel in the longitudinal direction. Reactor device according to at least one of claims 1 to 3, characterized in that the cylindrical reactor housing in the area the base of the product collection cone has breakthroughs that are at least a free area release from 25. Reactor device according to at least one of claims 1 to 4, characterized in that the cylindrical reactor housing ( 4 ) at the top of a product feed ( 9 ) having. Reactor device according to claim 5, characterized in that in the upper area zenith of the cylindrical reactor housing ( 4 ) below the product feed nozzle ( 9 ) a product distribution device ( 10 ) is provided. Reactor device according to at least one of claims 1 to 6, characterized in that in the upper region of the cylindrical reactor housing ( 4 ) at least one vapor and / or exhaust nozzle ( 11 ) is provided. Reactor device according to claim 7, characterized in that the at least one vapor and / or Exhaust nozzle horizontal or tangential with a slope of up to to 30 is arranged from the horizontal. Reactor device according to at least one of claims 1 to 8, characterized in that the hollow cylinder rotor ( 5 ) eccentrically in the cylindrical reactor housing ( 4 ) is arranged. Reactor device according to claim 9, characterized in that the horizontal longitudinal axis of the hollow cylindrical rotor ( 5 ) in the vertical direction to the product collection cone ( 8th ), to the cylindrical reactor housing ( 4 ) is arranged offset. Reactor device according to at least one of claims 1 to 10, characterized in that the hollow cylinder rotor ( 5 ) is designed as a closed frame and / or as Korblochzarge. Reactor device according to claim 11, characterized in that the rotor frame ( 5 ) to the end cover ( 19 ) of the reactor housing ( 4 ), but does not touch them. Reactor device according to claim 12, characterized in that between the end covers ( 19 ) and the rotor frame ( 5 ) circumferential resilient scrapers ( 7 ) are arranged. Reactor device according to claim 12 or 13, characterized in that the space between the end covers ( 19 ) and the rotor frame ( 5 ) has a supply of inert gas. Reactor device according to at least one of claims 1 to 14, characterized in that the ratio of the Korbrührerdurchmessers to Container diameter of the reactor is 0.98 to 0.82. Reactor device according to at least one of claims 1 to 15, characterized in that the ratio of the Rotorzargendurchmessers to Reactor diameter between 0.5 and 0.8. Reactor device according to at least one of claims 1 to 16, characterized in that the ratio of the reactor length to Reactor diameter between 0.5 to 1.5. Reactor device according to at least one of claims 1 to 17, characterized in that the annular film-forming elements ( 6 ) by a tubular rim ( 12 ) and one between the tubular rim ( 12 ) and the rotor surface spanned net-like metallic tube structure is formed. Reactor device according to claim 18, characterized in that that the net-like metallic structure forms rhombic and / or triangular openings. Reactor device according to claim 17 to 19, characterized characterized in that the ratio of the pipe ring diameter to the stirring basket diameter 1.2 to 2.5 to 1. Reactor device according to one of claims 18 to 20, characterized in that the remaining webs of the basket hole frame dressed in the inner area with semicircular and / or triangular profiles are. Reactor device according to one of claims 1 to 21, characterized in that the scrapers are triangular and preferably carried out so and are set so that the heated / cooled rotor frame as a thin film generator is working. Reactor device according to at least one of claims 1 to 22, characterized in that the cone tip of the product collecting cone ( 8th ) in a product take-off flange ( 14 ) ends. Reactor device according to claim 23, characterized in that the product take-off flange ( 14 ) directly with a discharge and / or Re circulation pump ( 15 ), whose inlet opening is preferably 1.5 to 3 times the total tooth cross-section of the pump. Reactor device according to claim 24, characterized in that the recirculation pump via a circulation line ( 16 ) with the inlet ( 2 ) connected is. Reactor device according to claim 25, characterized in that in the circulation line ( 16 ) a filter device ( 17 ) is arranged. Reactor device according to claim 25 or 26, characterized in that in the circulation line ( 16 ) additionally an online viscosity measuring device ( 18 ) is arranged. Process for the batchwise polycondensation of Oligomers / monomers, characterized in that a reactor device according to at least one of the claims 1 to 27 is used. Method according to Claim 28, characterized that at the beginning of the polycondensation, the reactor device up to a filling volume filled from 15 to 40% and then in the course of polycondensation depending from the product viscosity the oligomer in quantity from 0.5 to 5 based on the filled mass via the product distribution device is recirculated. Method according to claim 28 or 29, characterized the polycondensation is carried out up to 205 MWE (monomer repeating units). Method according to at least one of claims 28 to 30, characterized in that with a heated closed Rotor frame and / or unheated basket hole frame at temperatures up to 350 ° C and Vacuum is worked to 0.1 mbar. Method according to at least one of claims 28 to 31, characterized in that the rotational speed of the basket motor in dependence from the power consumption of the basket or the viscosity of the polymer / oligomer selected or regulated. A method according to any one of claims 28 to 32, characterized in that mass-related surface recharge rates of 300 to 600

be achieved and made the heated, stripped basket rotor this contribution of 30 to 50. Method according to at least one of claims 28 to 33, characterized in that the polycondensation time in the range from 30 to 120 minutes. Method according to at least one of claims 28 to 34, characterized in that for heating / cooling of the housing and Rotor organic fluid in liquid or vaporous form be used. Method according to at least one of claims 28 to 35, characterized in that during the product discharge the melt is still kept under a negative pressure. Method according to at least one of claims 28 to 36, characterized in that at the end of the product discharge the reactor with atmospheric Inert gas purged becomes. Method according to at least one of claims 28 to 37, characterized in that the reaction at 5 to 20 ° C above the melting point of the polymer is carried out.