WO2009027386A1

WO2009027386A1 - Method and devices for producing precondensed resin solutions

Info

Publication number: WO2009027386A1
Application number: PCT/EP2008/061125
Authority: WO
Inventors: Andreas Endesfelder; Katarina Rot; Christian FÜRST; Ingo Christian Nerger
Original assignee: Borealis Agrolinz Melamine Gmbh
Priority date: 2007-08-30
Filing date: 2008-08-26
Publication date: 2009-03-05
Also published as: DE102007041796A1

Abstract

The invention relates to a method for producing precondensed resin solutions, wherein a) the starting materials of the resin solution are made of at least one aminoplast former and at least one carbonyl compound and b) in at least one heating step (C1), the starting materials are directly heated. The invention also relates to a device that is suitable, in particular, for carrying out said method.

Description

Processes and apparatus for preparing pre-condensed resin solutions

The present invention relates to a method according to claim 1 and a device according to claim 90, which can be used in particular for the production of precondensed resin solutions. In this case, by means of direct heating, a rapid heating rate can be achieved and products can be produced with a narrow distribution of the degree of polymerization.

Pre-condensed resin solutions find versatility, especially in the woodworking industry, e.g. in the production of laminates or chipboard. In their preparation, the polymerization is stopped so early that the resin is still soluble and thus can be further processed in dissolved form. During further processing, the resin is then condensed to complete the polymerization. The resin thus obtains its thermosetting properties.

Since polymerization reactions proceed in the form of a stepwise condensation reaction, stopping this reaction before its completion inevitably results in a mixture of materials of different degrees of polymerization in the resin solution. Thus, there is a spectrum of low condensed materials (e.g., starting materials and monomers) and more condensed polymers. For many applications, however, it is desirable to keep the breadth of this spectrum as close as possible.

It is known to produce pre-condensed resin solutions in large, heatable stirred tanks in batches (ie in the batch process). For this purpose, the starting materials (eg aminoplastics,

Carbonyl compound and optionally catalyst) is usually introduced into the boiler cold, then heated to reaction temperature and cooled again after completion of the reaction time. The heat input occurs by means of heat transfer from heated surfaces (e.g., the vessel wall) to the fluid. The proportions of heat exchange surface and reactor volume that can be represented on an industrial scale limit the rate at which the reaction solution can be heated. If the heating times are to be reduced to the most economical possible, this leads to an inhomogeneous temperature distribution in the reactor. As a result, products having a broad distribution of the degree of polymerization are produced.

If one or more starting materials are not in solution at the beginning of the reaction, but rather as suspended solids, this disadvantage is even more pronounced: due to the slow heating up, only part of the solid initially passes into solution and is therefore already available for the reaction while the other one is available Part of the solid is redissolved later and can react. This broadens the spectrum of the degree of polymerization in the resulting resin solution. Another disadvantage of the low heating rate of conventional methods is that the time required for the heating phase has a reducing effect on the space-time yield and thus on the production capacity of corresponding installations.

These disadvantages can be partially absorbed by a continuous mode of operation: The heated surface located in the heating stage of such a reaction system is used throughout the time and thus more effectively for heating. Therefore, more favorable surface area to volume ratios and an increase in the heating rate can be achieved within certain limits. In continuous processes, even a very rapid increase in temperature can be achieved: If the cold or preheated educts are passed continuously into a thoroughly mixed stirred tank at the reaction temperature, an almost sudden increase in temperature takes place. However, the larger this temperature jump, the longer the average residence time in this fully mixed zone must be. The resulting broadening of the residence time distribution in the reaction system, however, results in a broad distribution of prevailing degrees of polymerization in the resulting resin solution.

The disadvantage associated with the heat input through heated surfaces of an inhomogeneous temperature distribution in the heating stage of the system can not be avoided in previous methods, even by means of continuous operation.

Continuous methods are e.g. in the patent DE-1595035 and patent application DE-1720306.

It is e.g. from US Pat. Nos. 4,131,113, 2,927,097 or DE-2161052, to carry out condensation reactions in tubular reactors.

The object of the present invention is to provide processes and devices for the production of precondensed resin solutions with as narrow a distribution of the degree of polymerization as possible. This implies, on the one hand, compliance with the lowest possible hydraulic residence time distribution and, on the other hand, the drastic minimization of spatial temperature gradients in the reaction mixture. For this purpose, it is also necessary to bring the reactants after mixing as quickly as possible to the reaction temperature in order to process such material systems, in which one or more Reactants are available at low temperatures only to a certain extent for the reaction (eg by insufficient solubility at low temperature). In addition, this measure improves the space-time yield of the process.

It has surprisingly been found that the required for this task, high heat input rates while minimizing spatial temperature gradients and only small broadening of the hydraulic residence time distribution are possible if the heat input not as in the previously known methods on heated surfaces, but via direct heating of the reaction mixture he follows.

For this purpose, the educts of the resin solution, namely at least one aminoplast-forming agent and at least one carbonyl compound are subjected to direct heating in at least one heating stage. A stage may comprise one or more apparatuses, each having one or more (sub) regions of different process conditions. The areas may also be arranged in the same apparatus in a spatial and / or temporal sequence.

For this purpose, a component present in liquid form in the reaction mixture (in particular a solvent) is advantageously mixed with the optionally preheated remaining components in a superheated state, preferably in vapor form. However, other methods of direct heating can be used or combined, for example: irradiation of the reaction mixture (microwaves, infrared, gamma or particle radiation, etc.), inductive heating (optionally with the addition of an electrically conductive, particulate phase if necessary later separated), adding a chemically inert, overheated phase, which is separated later if necessary, etc. The object is also achieved by a device according to claim 89. The device comprises at least one fumigant for introducing a gas or a vapor for directly heating at least one liquid and / or a suspension and an agitator, wherein the agitator by substantially radially arranged blades or flow channels promoting with respect to the at least one liquid and / or Suspension is.

Further advantageous embodiments are subject of the dependent claims.

The invention will be explained in more detail below with reference to the figures of the drawings of several embodiments. Show it:

FIG. 1A shows an embodiment of an arrangement with a continuous sequence of process stages arranged in succession in space; FIG.

FIG. 1B shows an embodiment of an arrangement with a discontinuous sequence of process stages arranged chronologically one after the other; FIG.

Fig. 2 is a schematic representation of a first

Embodiment of a continuous process and embodiment of a continuous apparatus with a tubular reactor;

Fig. 3 is a schematic sectional view through a

Embodiment of a continuous device; Fig. 4 is a schematic sectional view through a

Embodiment of a discontinuous device;

5 shows an exemplary embodiment of a continuous method with static mixer and calorimetric measuring section;

Fig. 6 embodiment of residence and Abkühlstufe in a continuous process.

Fig. 7 Especially for a F: M ratio of 1.3 possible

Operating parameters for an embodiment of the continuous process.

In connection with FIG. 1A, IB, embodiments of the method according to the invention are represented in the form of block diagrams. Fig. IA describes a continuous process.

In this case, in Fig. IA, the starting materials of a resin solution, e.g. an aminoplast generator, phenol or a phenol derivative and a carbonyl compound and a catalyst of at least one heating stage 1 fed. As will be described later, a direct heating takes place in the at least one heating stage.

After heating, the product of the heating stage 1 is at least one residence time 2 fed. After the substances have spent a predeterminable time in the at least one residence time stage 2, the substances are fed to at least one cooling stage 3. In Fig. IA, the process steps are continuously formed and spatially arranged so as to pass through one after the other.

FIG. 1B shows an alternative flow diagram with a discontinuous procedure, in which the process step of filling 5 of the at least one heating stage 1 with the educts is carried out. The educts may correspond to those of the example illustrated in FIG. 1A.

At least one heating stage 1 here means that several heaters with direct heating can be carried out in one container.

Subsequently, in the same container or in the same containers, the lingering, i. the at least one dwell time level 2. Again, the dwell in one stage or in several staggered stages can be done.

Finally, there is at least one cooling stage 3 with a subsequent emptying and a subsequent filling.

It is clear from FIGS. 1A and 1B that the term stage in connection with a continuous method (FIG. 1A) can mean a spatial arrangement of apparatuses for the realization of stages. In the discontinuous case (FIG. IB), step means the temporal succession of certain operating states. In connection with FIG. 2, a continuous plant is shown as an exemplary embodiment for the production of precondensed resin solution.

As an example, the preparation of a formaldehyde melamine resin is described here, wherein other resins, in an analog system and with an analogous method can be produced.

Suitable starting materials for the resins are aminoplastics, e.g. Urea, at least one urea derivative, at least one dicyandiamide, at least one guanamine, melamine and / or at least one melamine derivative. In principle, however, it is also possible that phenol or phenol derivatives can be used as starting materials. In the following, however, aminoplastics are considered.

The reactant for the aminoplast formers is at least one carbonyl compound, e.g. an aldehyde, especially formaldehyde. The formaldehyde may be used, for example, in whole or in part as a formalin solution and / or as paraformaldehyde.

The process is carried out in a plant which consists of several, substantially serially connected stages, which are flowed through by the reaction mixture continuously. In this respect, this embodiment is an embodiment of the method shown in principle in Fig. IA.

In alternative embodiments, it is also possible to switch individual stages or partial areas of the stages in parallel. Here, particulate melamine is fed via the metering device H1 to a first container M1 as an educt. The melamine serves as Aminoplastbildner in the following processing.

As a further starting material and as a carbonyl compound here formaldehyde (and brine) is fed into the first container Ml.

In a first step, a premix of the reaction components with a reduced water content compared to the required reaction mixture is prepared (stirred tank Ml). In this case, a pre-tempering of the premix can be made via the heating jacket of the stirred tank Ml.

Via a pump Pl, which preferably as

Progressing cavity pump is executed, the premix is promoted in the heating stage Cl, which is designed here as a continuous stirred reactor. The heating stage Cl is here under an operating pressure of 6 bar.

The content of the heating stage Cl is brought by direct heating to a temperature of about 137 ⁰ C. The direct heating takes place here by the introduction of steam via a control valve V2 in the heating stage Cl.

For this purpose, a temperature controller TCl via the valve V2 so much steam that a corresponding discharge temperature is reached. This steam condenses in the heating stage Cl to liquid water and heats the mixture by the resulting heat of condensation on.

To adjust the required water content of the reaction mixture, more water is added in liquid form Control valve Vl added. This amount is controlled via a ratio controller FV3 so that the mass flow flowing out of the heating stage Cl is in the correct ratio to the incoming premix.

The premix is thereby diluted in the appropriate ratio with water, so that sets a solids content of about 57% in the produced resin solution. The control loops described are parameterized in such a way that a largely steady state of equilibrium is established during operation.

In a specific embodiment of the described control, the control valve Vl can be controlled via a flow controller, which in turn receives a desired value for the flow rate of the valve Vl from the ratio controller FV3. Similarly, the flow measurement FIl can be expanded to the controller, which receives a setpoint for the flow in the pump Pl from the ratio controller FV3 and controls them accordingly.

In a further embodiment of the method (see Fig. 5), the discharge temperature of the heating stage Cl is controlled by the amount of water added via Vl means the temperature controller TCl. As much steam is added via the valve V2 that results in a suitable running mass flow from the heating stage Cl in relation to the incoming premix. This ratio is controlled by the ratio regulator FV3, which controls valve V2.

As an alternative to the conventional control strategies shown here, a model-based control algorithm can also be used to control the dilution and the temperature in Cl. The average hydraulic residence time of the reaction mixture in the heating stage Cl is 45 s. In this case, the melamine supplied in suspension passes completely or partially into solution.

In other embodiments (as illustrated, for example, in connection with Figures 3 and 4), the hydraulic residence time in the heating stage may also be shorter or longer. It is advantageous if the mean hydraulic residence time in the at least one heating stage is less than 60 minutes, preferably less than 20 minutes, more preferably less than 5 minutes, most preferably less than 1 minute.

As soon as the reaction mixture has been heated to such an extent that the reaction begins to a significant extent, advantageously the residence time should be distributed as uniformly as possible over all volume elements of the reaction mixture until the reaction is virtually stopped again by sufficient cooling.

If one considers the stages or partial regions which have a corresponding temperature as a flow system, its residence time distribution should therefore be as narrow as possible.

It is thus advantageous if the hydraulic residence time distribution of this flow system and / or over all heating and Verweilzeitstufen a standard deviation of less than 60%, especially less than 40%, more preferably less than 25%, more preferably less than 15% and most preferably less than 9% has the corresponding space-time.

For the determination of the hydraulic residence time distribution and its standard deviation, the following applies: If the distribution is determined at discrete points (eg by measurements in a tracer test), then sufficiently many (at least 100) detection points are to be selected at equidistant time intervals. The Residence time distribution is to be determined at least up to 4.5 times the spacetime and the standard deviation over the interval from 0 to 4.5 times the spacetime. The centroid of the determined residence time distribution must correspond more exactly than +/- 2% with the corresponding space-time. The hydraulic parameters in determining the residence time distribution must be in accordance with the actual operating conditions.

Space-time is understood to mean the quotient of liquid volume and volume flow.

It is advantageous if the heating rate of the inlet temperature to the starting temperature, in particular in the last portions of the heating stage and / or in the entire heating stage is greater than 1 ° C per minute, in particular greater than 30 ⁰ C per minute, more in particular greater than 150 ⁰ C per minute, more preferably greater than 380 ⁰ C per minute.

The temperature at the outlet of the heating stage is advantageously at least 90%, in particular at least 95%, very particularly at least 97% of the average reaction temperature in Celsius.

It is also advantageous, depending on the reactants used, that the temperature at the exit of the heat-up from 60 to 230 ° C, in particular between 70 and 200 ⁰ C, more preferably between 80 and 180 ⁰ C and most preferably between 110 and 150 ⁰ C. is.

In a particular embodiment of the process, for example, for MF resins having an F / M ratio of from 1.3 to 2.4, temperatures of from 120 to 140 ^° C. are particularly advantageous. Especially for in Fig. 7 as an embodiment resin type shown in this embodiment, a temperature between 135 and 140 ⁰ C is particularly preferred.

By MF resin is meant a resin with melamine as the aminoplast former and formaldehyde as the carbonyl compound. The F / M ratio denotes the mass ratio of the educts formaldehyde to melamine.

The reaction mixture leaving the heating stage C1 is then passed into the residence time stage C2, which is designed as a tube reactor. A residence time stage C2 is generally understood to mean a device in which the materials are held for a predetermined time, so that a reaction can take place. It is possible, but not mandatory, that a temperature control and / or temperature maintenance is provided.

It is advantageous if the mean hydraulic residence time in the at least one residence time step C2 is less than 10 hours, preferably less than 2 hours, more preferably less than 45 minutes, most preferably less than 15 minutes.

In a particular embodiment of the process, residence times of from 6 to 12 minutes, for example, are particularly advantageous for MF resins having an F / M ratio of from 1.3 to 2.4. Especially for the resin type shown as an exemplary embodiment in FIG. 7, a residence time between 6 and 9 minutes is particularly preferred in this embodiment.

The individual pipe sections which make up this residence time stage are accommodated in a steam-heated jacket in the manner of a shell-and-tube heat exchanger, but these pipe sections are essentially connected in series. Through the pipe surface, the reaction mixture is so tempered that the heat of reaction and the energy required for a possible redissolution of melamine still in suspension are compensated and the temperature of the reaction mixture, for example for the resin type shown as an embodiment in FIG. 7 remains at about 137 ⁰ C. The tube diameter of the residence time C2 is selected so that Reynolds numbers greater than 2300 and thus present turbulent flow conditions. The volume of the residence time C2 is chosen so that the reaction mixture flows through this zone with a mean residence time of about 7 minutes and thereby converted to a resin solution having the desired degree of polymerization.

As a criterion for the ongoing control of the

Degree of polymerization, the water compatibility of the resin solution produced is determined manually at certain intervals by titration or determined continuously via an online measuring device. The online measurement of the following material properties of the resin solution produced can also be used as a criterion for controlling the degree of polymerization: density, viscosity, conductivity, refractive index, dielectric constant and / or light scattering and diffraction.

In a further embodiment of the method, the heat of reaction can also be evaluated calorimetrically as a measure of the progress of the reaction. For this purpose, at least one adiabatic measuring section A1 is placed within or after the residence time step with a measuring point for its inlet temperature (TI 2) and outlet temperature (TI3) (see FIG. 5). The temperature difference can be determined very accurately and is a measure of the evolution of heat of the reaction in the measuring section.

On the basis of such measurement results, if necessary, a fine-tuning of the degree of polymerization is carried out during operation, which takes place manually or via a model-based control algorithm. Such tuning is possible within certain limits via the variation of reaction temperature and throughput.

On the one hand, however, the throughput should always remain so high that the critical Reynolds number in the tubular reactor is not undershot. On the other hand, compliance with a limit temperature may be required to achieve certain resin qualities, which should not be exceeded during operation.

Are coarser changes desired to tune the degree of polymerization, so can in the

Rohrbündelwärmeübager executed residence time C2 bridged individual pipe sections or such a bridging be repealed, so as to change the reaction volume.

The running out of the residence time C2 resin solution is passed into the condenser Wl, which is similar to the residence time C2 constructed as a tube bundle heat exchanger. The cooler Wl is thus a cooling stage Wl for the reaction mixture.

The tube diameter is chosen so that the hot resin solution is cooled very rapidly under turbulent flow conditions to a temperature level below the reaction temperature. In the further course of the pipe diameter is preferably chosen to be larger, so that the increasing viscosity with decreasing temperature does not lead to an excessive pressure loss.

The finished resin solution flowing out of the cooling stage W1 is guided via a valve V3, which can be designed as a pressure-retaining valve (see FIG. 5), in particular as a pinch valve. The pressure drop at this valve is adjusted so that the boiling pressure of the reaction mixture every point in the system is exceeded with sufficient certainty. For example, for the resin type shown as an embodiment in FIG. 7, an operating pressure of 6 bar can be set in the heating stage C1. Particularly preferred is the design of the valve V3 as a control valve (see Fig. 2), in particular as Schlauchquetschventil and control of this valve by a pressure regulator PICL. The pressure regulator is designed so that it ensures at one or more measuring points, which have a high temperature level and / or a high vapor pressure of the reaction mixture, exceeding the boiling pressure. This makes it possible, in a particularly economical manner, to keep the operating pressure of the plant as low as possible and to make use of the relaxation of the reaction mixture to some extent in order to overcome the pressure loss of the cooling stage (s).

The valve V3 can be followed by further cooling stages.

The direct heating is carried out in the heating stage Cl of the continuous process. Due to the achievable high heat input rates, this stage can be kept relatively small, so that it also reactor vessels with high backmixing (e.g., stirred tank) can be used without causing an excessive broadening of the hydraulic residence time distribution in the entire system. Furthermore, static mixers, as shown in the exemplary embodiment of FIG. 5, or jet pumps or jet mixers 84, as shown in the exemplary embodiment of FIG. 6, can also be used for the heating stage C1.

As stated in connection with FIG. 1A, the heating stage C1, the residence time stage C2 and / or the cooling stage W1 can also be configured differently in terms of apparatus, as shown in FIG. In particular, the stages can each Be distributed over more than one apparatus and be connected in series and / or parallel.

In the heating stage Cl, the reactants of the polymerization at storage temperature or preheated state are initiated. Urea, melamine or their derivatives are preferably used for the preparation of condensation resins. The combination of several Aminoplastbildner can be used. Phenol or phenol derivatives can also be used as starting materials.

The reactive component used is a carbonyl compound, preferably an aldehyde, in particular formaldehyde. Other reactive components incorporated as modifiers in the network of the resulting condensation resin may also be added (eg, especially a monohydric alcohol, a polyhydric alcohol, a caprolactam, a polyol, in trimethylopropane, a sorbitol, glucose, sulfite, toluenesulfonic acid amide Carbamate, a salt of the maleic or fumaric acid monoamide and / or an aminoalcohol)

The addition of customary additives, for example dyes, can already take place in this production step.

It may also be the addition of a solvent. Most types of resin also require the addition of one or more catalysts, usually consisting of an acid or a base. A variant of the method according to the invention provides for the addition of the catalyst only in a downstream stage, so that the heating stage is operated in this case essentially not for the reaction, but for heating and optionally for mixing the reaction components. Subsequently, the reaction mixture brought to the reaction temperature reaches one or more residence time steps.

The residence time stages are preferably designed as turbulent flows through tubular reactors. However, the use of internals (e.g., perforated plates) which equalize or increase the flow rate across the tube cross-section also allows tube reactors to be used under non-turbulent operating conditions.

The residence time stages are essentially connected in series. However, individual stages of this series may also include parallel connected regions 81 as shown in FIG

In addition, a cooling stage 80 may include one or more areas 82 bridged by a bypass so that volume adjustment of the residence time stage may be made.

If one or more of the reactants are present as suspended solids in the reaction mixture at the beginning of the reaction, their dissolution process need not be completed within the heating stage. Rather, the dissolution process may also come to an end at the beginning of the residence time stages and optionally be limited by the solubility product of the substance in the solvent, so that redissolving of the substance is only possible in the further course of the reaction. Preferably, in such a case, as shown in Fig. 6, the first region 83 of the first residence time 80 is formed so that any not yet dissolved residues are operationally controllable by deposits of undissolved residues is prevented by means of vertical flow control or increased flow rate or such in their consequences by a particularly easy accessibility for cleaning or replacement measures can be made manageable.

An object of the method according to the invention, however, is to achieve a dissolution of such substances as quickly as possible and in particular not to hinder them by slow heating processes.

The amounts of heat transferred in the residence time stages are generally comparatively low and merely serve to maintain the temperature or to adjust the temperature within the framework of a temperature profile variable in the course of the reaction. Therefore, in these residence time stages, heat transfer can take place through corresponding heat exchange surfaces (preferably through the tube wall) without causing harmful temperature gradients. If, in the context of a temperature profile required for the reaction or due to its heat of reaction, larger amounts of heat must be exchanged in one of the subsequent residence time stages, this can take place via an intermediate further stage for direct heating or an evaporator, so that the temperature gradients in the reaction medium can be kept low.

The reaction system formed from the described stages is so dimensioned in its volume that, after the average residence time required for the reaction has elapsed, the reaction solution exits from the last residence time stage. From there, it is sent to a cooling stage to stop the reaction. If further processing of the resin solution at an elevated temperature level is required (eg spray-drying), the cooling can be completely or partially dispensed with if the further processing takes place sufficiently quickly or immediately after the reaction and the residence time in the reaction system is correspondingly shortened if necessary, so that excessively advanced polymerization of the product is avoided. The cooling stage has, as shown in FIG. 6, preferably a plurality of subregions, designed to initially enable a rapid cooling at the most turbulent flow conditions in accordance with closely sized pipe cross-sections (85) and also to minimize the spatial temperature gradients. Advantageously, for the first region of the cooling stage, an evaporator (preferably a flash evaporator) can be used. In the embodiment of FIG. 6, the flash evaporation is realized via an expansion valve 89 and a separator 87, which is preferably designed as a cyclone. The resulting vapor is passed into the condenser 88 and condensed there. The resulting in the separator resin solution is fed to the next region 85 of the cooling stage, which has a narrower dimensioned pipe cross-section.

The further the resin solution already under her

Reaction temperature is cooled, the slower or at the larger spatial temperature gradient, the further cooling can take place without the spectrum of the degree of polymerization contained in the product appreciably increases in width. Preferably, the last region (s) 86 of the cooling stage are therefore dimensioned so that there is a lower flow velocity, which possibly makes turbulence no longer possible, but restricts the build-up of undesired pressure losses. In order to improve the heat exchange, in particular under non-turbulent flow conditions, corresponding static mixing elements can be arranged in the cooling stage.

A further embodiment of the cooling stage provides for the addition of a cold medium (preferably of the solvent used in the reaction) in the first region of the cooling stage, or immediately after the evaporator. The medium used for cooling can also be particulate in solid State of aggregation are added so that it melts in the resin solution and deprives her of heat in this way.

After leaving the cooling stage, the resin solution can be further processed or stored or filled. It should be noted that most types of resin in solution only for a limited period of storage are stable and must be correspondingly early to further processing (for example, to solid resin or laminates) must be supplied.

The invention further provides a device with which the direct heating taking place in the heating stage of the continuous process described above can be carried out. In principle, this device according to the invention can also be used for other reaction systems.

The device allows in the manner of a continuously operated Begasungsrührers the merging and intensive mixing of the incoming liquid medium with a vaporous medium, which condenses, so that a heating of the liquid medium by the resulting condensation heat is the result. For this purpose, the contents of the stirred tank is kept under a pressure which is above the boiling pressure at the operating temperature. In addition to pure liquids, liquid media in the broader sense, in particular suspensions, can also be treated in the agitator according to the invention.

A gassing stirrer is only one example of a gassing device which, for example, may also have a special nozzle system with which the reaction mixture can be mixed. The agitator and the essential flow processes occurring therein are shown in FIG. This embodiment can be used, for example, as heating stage C1 in the embodiment according to FIG. 2.

Preferably, the stirred tank 30 has curved bottoms and is cylindrical. Within the inlet nozzle 32 for the premix, a hollow shaft 34 rotates, which is sealed with respect to the inlet nozzle with the sealing system 35. This is preferably designed as a double-acting mechanical seal (details not shown in the drawing). The inlet nozzle 32 is preferably mounted axially below the stirring vessel.

Located on the hollow shaft 34 and driven by this, an effective as a gassing agitator stirrer is mounted, which consists of several elements:

The stirring element has, in the manner of a blade or disc stirrer, a horizontal, circular disk 40, the top and bottom of which are equipped with essentially radially extending blades 36. On the upper blades, a cover plate 37 is preferably attached, which has an inlet opening in its center. Alternatively, the blades 36 may be disposed on only one side of the disk.

The disc contains on its top and bottom discharge openings 38, through which steam is introduced fine bubbles for heating in the funded by the stirrer reaction medium. This steam is fed via the hollow shaft 34 in the disc. Within the disc is a preferably adjustable distribution system, which accomplishes the distribution of the steam outlet between the top and bottom or on the individual outlet opening. In the illustrated embodiment, the distribution system via a hollow screw (41) is realized with lateral holes. Due to the vertical positioning of this as an outlet opening functioning holes, the distribution between the top and bottom exiting steam amount can be varied.

At the level of the stirrer is optionally located on the inside of the container wall, an annular guide plate 30. This baffle 30 deflects the conveyed on the bottom of the agitator fluid so that it remains largely below the agitator and is sucked from there back into the agitator. The conveyed on the top of the agitator fluid is deflected so that it remains largely above the stirring member and is sucked in again by an optional guide tube 39 by the stirring member. By this type of flow guidance, two well-mixed areas within the stirred tank form, between which a reduced exchange of fluid exists. The inlet-side region preferably has a smaller volume than the outlet-side. As a result, rapid heating of the inflowing premix is achieved in the inflow-side region, while the second region effects reheating and further mixing between the fluid elements. This ensures intensive heating, mixing and compensation of temperature and / or concentration fluctuations in a small space. In this case, the residence time distribution of the overall system can be kept relatively narrow because the fully mixed zones of the heating stage are small in relation to the residence time and divided into two areas.

In the advantageous upward flow-through design of the agitator, which is shown in FIG. 3, the inlet connection 32 for the inflowing premix is preferably through-stretched through the lower bottom and brought close to the stirring element. As a result, the incoming premix can flow directly against the underside of the stirring element, so that no gas cushion can form there. As a result, the conveying efficiency of the stirring member is maintained. In a simplified, not shown here embodiment of the agitator according to the invention, the supply of steam and premixing can also take place via corresponding inlet pipes, which introduce outside the agitator axis to the underside of the stirring body.

In addition, the agitator can optionally be equipped with baffles or baffles that prevent excessive rotational flow of the container contents. Furthermore, the agitator may also be equipped with several, in particular similar, stirring bodies, which are arranged either on a common shaft or on several shafts.

The heated and mixed with the condensed vapor reaction medium leaves the stirred reactor via the outlet pipe 33rd

The subject of the invention is also a discontinuous process and a corresponding device, e.g. for the preparation of resin solution described here can be used. In principle, however, this device according to the invention can also be used for other reaction systems.

The following describes the batchwise preparation of the precondensed resin solution using direct heating. The reactor is designed so that it can be operated at pressures above the boiling pressure of the reaction mixture at the reaction temperature.

At the beginning of the process cycle, the reactants of the polymerization at storage temperature or in the preheated state are introduced into the reactor. For the preparation of condensation resins, urea, melamine or their derivatives are preferably used as the amino resin former. Also, at least one urea derivative, at least one dicyandiamide or at least one guanamine, melamine can be used.

The combination of several Aminoplastbildner can be used. The reactive component used is a carbonyl compound, preferably an aldehyde, in particular formaldehyde. Other reactive components incorporated as modifiers in the network of the resulting condensation resin can also be added (e.g., alcohols). The addition of customary additives, for example dyes, can already take place in this production step. As a rule, the addition of a solvent also takes place. Most types of resin also require the addition of one or more catalysts, usually consisting of an acid or a base. A variant of the method according to the invention provides for the addition of the catalyst in whole or in part only at a later stage of the process cycle.

After completion of filling, the heating stage of the process cycle begins (see Fig. IB). In this case, the direct heating is carried out within the reaction system. Due to the achievable high rates of heat input, this stage can be kept relatively short, so that advantageously results in an increased space-time yield of the process and reactants, which are present as a solid as quickly as possible or as far as possible and made available for the reaction.

The reaction usually starts during the heat-up stage, but mainly takes place subsequently within one or more residence time stages. However, a certain reaction progress is usually recorded during the subsequent cooling.

In the residence time stage, a heat exchange is either only for temperature maintenance or to compensate for heat losses or to set a temperature profile in the course of the reaction progress required.

If the heat exchange during the residence time is low, then this can be carried out by means of heat exchange surfaces, which are heated or cooled accordingly. Preferably, however, a necessary heat input takes place with the already described means of direct heating and a dissipation of heat by evaporation. This is particularly advantageous when the heat of reaction in the synthesis of the desired type of resin is significant.

After completion of the residence time (s), rapid cooling preferably takes place by evaporation. This allows a rapid termination of the reaction. Finally follows the emptying, in which the product is discharged from the reactor. For example, the product is fed to a refrigerated tank by storing it until further processing. Then the process cycle starts again.

During cooling or during the reaction, the described evaporation steps for heat removal by lowering the operating pressure in the reactor, so that the reaction mixture begins to boil. Preferably, a solvent having a high vapor pressure is selected, so that substantially pure solvent evaporates here. The vapors are discharged from the reactor and condensed in a condenser. If the steam consists of only slightly contaminated water, it can also be released directly to the atmosphere. In order to separate the high amounts of steam required for rapid cooling from the reaction mixture and to facilitate effective phase separation, it is possible to use an agitator which rotates just below the self-adjusting liquid level of the reaction mixture. The stirring element used is preferably a paddle stirrer sucking from below. To improve the mixing of the reactor, the agitator may be equipped with a guide tube. In addition, the agitator can optionally be equipped with baffles or baffles that prevent excessive rotational flow of the container contents. Furthermore, the agitator may also be equipped with a plurality of, in particular similar, stirring bodies, which are arranged either on a common shaft or on several shafts.

This method will be explained in connection with FIG. 3 with reference to a further embodiment.

In the filling stage of the production cycle of the stirred reactor 51 is filled via the inlet port 60 with preheated formalin solution, KOH and melamine. These starting materials can be introduced individually or as premix.

The external preheating has the advantage that the time required for the temperature does not need to be taken into account in the cycle time of the actual reactor. Thus, the preheating can be slower and with the use of waste heat, which comes for example from the product cooler or condenser, take place. Preheating can take place below the boiling point or below the temperature at which a reaction already begins to a considerable extent. In practice, for example, for MF resins having an F / M ratio between 1.3 and 2.4, an advantageous temperature within the range of 40 to 90 ^° C. results.

The further heating of the reaction mixture advantageously takes place rapidly, so that the melamine used as aminoplast is dissolved as quickly as possible with the onset of reaction. For this purpose, the heat-up stage of the production cycle with a gas distribution stirrer, water vapor is introduced into the reaction mixture which is brought to, for example, 137 ⁰ C and the desired solids content. An optimally arranged for the described heating stirrer 55 is placed in the lower part of the stirred reactor, it is driven by a hollow shaft and supplied with steam, which flows through appropriate outlet holes fine bubbles into the reaction mixture. A guide tube 54 arranged above the stirring body ensures during the heating stage that the circulation through the stirring body 55 extends to the entire liquid reactor contents.

In the residence time stage, which adjoins and which lasts, for example, about 9 minutes, temperature losses can be compensated via an optional heating jacket 61.

Once the desired degree of polymerization has been achieved, it is advantageous to slow down the reaction as quickly as possible by pre-cooling. This is done in the illustrated agitator by lowering the pressure by means of discharge of gas through the outlet stub 58 with simultaneous start-up of the degassing stirrer. Whose stirring body 52 is located just below the surface of adjusting itself in his operation Trombe. Via the guide tube 54, he sucks liquid from below, so that even during the cooling phase of the complete container contents is circulated intensively. The lowest pressure within the system occurs in this process on the blades of the degassing stirrer, where therefore the evaporation of the liquid preferably starts, so that the resulting vapor can escape relatively easily to the liquid surface. In the Trombe itself also takes place due to the centrifugal forces an enrichment of gas bubbles in the direction of agitator axis. These processes allow a high evaporation rate in the described agitator.

When the contents of the agitator are relieved to atmospheric pressure, the described cooling process comes to a halt at temperatures around 100 °. This is sufficient to slow down the reaction considerably. After the subsequent emptying stage, which lasts about 5 minutes, however, a further cooling of the resin produced must take place, provided that this can not be further processed immediately. For this purpose, the finished resin solution is passed through the outlet nozzle 62 in a cooling container by preferably pre-cooled resin solution is already produced, so that there is a further rapid cooling of the same when mixing the fresh, hot resin solution. The cooling tank is equipped with appropriate heat exchange surfaces (eg pipe coils) to dissipate the accumulated heat can. The cooled resin solution is removed at temperatures between 30 and 80 ° C from the cooling tank for further processing or storage.

A simplified embodiment of the agitator shown in FIG. 4 can either dispense with the degassing stirrer and the possibility of precooling or else abandon the particularly favorable positioning of the gassing stirrer arranged at the bottom. In the latter case, the above-arranged stirrer under respective respective pressure conditions for both degassing and for gassing is effective when the drive shaft is designed as a hollow shaft with steam supply and appropriate outlet openings for the steam are preferably provided in the outer Rührkörperbereich. Particularly advantageous in this case is the design of the stirring body with alternately upward and downward flow channels and attachment of the steam outlet openings in the region of the downwardly directed flow channels.

If the agitator, as shown in Fig. 4, operated with two Rührkörpern, it should be noted that only one of the stirrers is put into operation. The suction via the guide tube 54 can then be done via the respective stationary stirrer.

Claims

claims

1. A process for the preparation of precondensed resin solutions, wherein a) the starting materials of the resin solution at least one

Aminoplastbildner and / or at least phenol and / or a phenol derivative and at least one carbonyl compound, b) the reactants with at least one heating stage (1, Cl) are subjected to a direct heating.

2. The method according to claim 1, characterized in that the product of the heating stage (1, Cl) at least one residence time (2, C2) is supplied.

3. The method according to claim 1 or 2, characterized in that the product of the heating stage (1, Ci; and / or the residence time (2, C2) at least one cooling stage (3, Wl) is supplied.

4. The method according to at least one of the preceding claims, characterized in that the average hydraulic residence time in the at least one heating stage (1, Cl) less than 60 minutes, preferably less than 20 minutes, more preferably less than 5 minutes, most preferably less than 1 minute.

5. The method according to at least one of the preceding claims, characterized in that the average hydraulic residence time in the at least one residence time (2, C2) less than 10 hours, preferably less than 2 hours, more preferably less than 45 Minutes, more preferably less than 15 minutes and most preferably less than 8 minutes.

6. The method according to at least one of the preceding claims, characterized in that the flow system, which is formed by the existing heating stages (1, Cl) and Verweilzeitstufen (2, C2), has a total of a hydraulic residence time distribution, which under hydrodynamic operating conditions and on the 4.5 times the spacetime, a standard deviation of less than 60%, in particular less than 40%, in particular less than 25%, more preferably less than 15% and most preferably less than 9% of the space-time.

7. The method according to at least one of the preceding claims, characterized in that the heating rate in the heating stage (1, Cl) from the inlet temperature to the outlet temperature greater than 1 C ° per minute, in particular greater than 30 ⁰ C per minute, in particular greater than 150 ⁰ C per minute, more preferably greater than 380 ⁰ C per minute.

8. The method according to at least one of the preceding claims, characterized in that the temperature at the outlet of the heating stage (1, Cl) is at least 90%, in particular at least 95%, especially at least 97i of the average reaction temperature in Celsius.

9. The method according to at least one of the preceding claims, characterized in that the temperature at the output of the heating stage (1, Cl) between 60 and 230 ⁰ C, in particular between 70 and 200 ⁰ C, preferably between 80 and 180 ⁰ C, particularly preferred between 110 and 150 ⁰ C, most preferably between 135 and 140 ⁰ C.

10. The method according to at least one of the preceding claims, characterized in that the cooling rate in the cooling stage (3, Wl) from the inlet temperature to the outlet temperature greater than 1 C ° per minute, in particular greater than 10 ⁰ C per minute, in particular greater than 100 ⁰ C per minute.

11. The method according to at least one of the preceding claims, characterized in that the at least one heating stage (1, Cl), residence time (2, C2) and / or the cooling stage (3, Wl) with at least one further stage serially and / or in parallel connected is.

12. The method according to at least one of the preceding claims, characterized in that the reaction medium is guided after reaching the reaction temperature for a preselected time to a predetermined temperature profile, in particular is maintained at a predetermined temperature.

13. The method according to at least one of the preceding claims, characterized in that at least urea, at least one urea derivative, at least one dicyandiamide, at least one guanamine, melamine and / or at least one melamine derivative is used as aminoplast.

14. The method according to at least one of the preceding claims, characterized in that the carbonyl compound is an aldehyde, in particular formaldehyde, acetaldehyde, isobutyraldehyde, acetone, methyl ethyl ketone and / or diethyl ketone.

15. The method according to claim 14, characterized in that the formaldehyde is used in whole or in part as a formalin solution and / or as paraformaldehyde.

16. The method according to at least one of the preceding claims, characterized in that at least one catalyst or catalysts are added in whole or in part only in one of the direct heating downstream stage to the rest of the reaction mixture.

17. The method according to at least one of the preceding claims, characterized in that at least one acidic or basic catalyst is used as further components.

18. The method according to at least one of the preceding claims, characterized in that as further components at least one modifier, in particular a monohydric alcohol, a polyhydric alcohol, a caprolactam, a polyol, a Trimethylopropan, a sorbitol, glucose, sulfite, Toluolsulfonsäureamid, a carbamate , a salt of the maleic or Fumarsäuremonoamids and / or an aminoalcohol is used.

19. The method according to at least one of the preceding claims, characterized in that as further components at least one additive, in particular a postforming additive for service life extension is used.

20. The method according to at least one of the preceding claims, characterized in that as a further component at least one solvent, in particular water or an alcohol is used.

21. The method according to at least one of the preceding claims, characterized in that the direct heating at least partially by a substance which is wholly or partially mixed in the gas or vapor state in the remaining reaction medium.

22. The method according to claim 21, characterized in that the wholly or partially added as a vapor component is a solvent.

23. The method according to claim 21 or 22, characterized in that the at least one heating stage (1, Cl) in which the admixing of the vaporous component for direct heating is divided into a plurality of sequential areas, so that in the first area a preheating or main heating and subsequent heating takes place in subsequent areas by adding further gas or steam.

24. The method according to at least one of claims 21 to 23, characterized in that the supplied gas quantity or amount of steam is controlled by a ratio control, which keeps the ratio of incoming premix and running reaction mixture constant, while the temperature control in the at least one residence time stage (2, C2) by addition of a liquid component diluting the resin solution, the variable portion of which does not substantially adversely affect the properties of the resin solution.

25. The process as claimed in at least one of claims 21 to 24, wherein a liquid component diluting the resin solution and the vaporous component fed for direct heating are substantially identical in terms of material.

26. The method according to at least one of claims 21 to 25, characterized in that a regulation of Expiration temperature of the at least one heating stage (1, Cl) via the added amount of gas or amount of steam.

27. Process according to claim 21, characterized in that the variability in the solids content of the resin solution produced, caused by the variability of the added amount of gas or steam, is controlled by an adjustment of the premix inlet temperature, so that after the adaptation the variability of the premix added amount of steam is significantly limited.

28. The method according to at least one of claims 21 to

27, characterized in that the variability in the solids content of the produced resin solution caused by the variability of the added amount of steam is compensated by means of a ratio control which keeps the ratio of incoming premix and effluent reaction mixture constant by adding a premix-diluting liquid component.

29. The method according to at least one of claims 21 to

28, characterized in that the vaporous component used for the direct heating and the liquid component diluting the premix consist of the same substance.

30. The method according to at least one of claims 21 to 29, characterized in that the amounts of gaseous or vaporous and non-gaseous or vapor-fed components are controlled by a model-based control algorithm, which determines the solids content of the produced resin solution and the discharge temperature of the at least one heating stage (1, Cl) regulates.

31. The method according to any one of the preceding claims, characterized in that the viscosity of the Reaction mixture, their density, their heat of reaction, their conductivity, their refractive index, their

Dielectric constant, their light scattering and diffraction detected and evaluated as a measure of the reaction progress and are used in particular for the correction of operating temperature and / or system throughput.

32. The method according to at least one of the preceding claims, characterized in that the direct heating takes place at least partially by irradiation, in particular with microwaves, infrared radiation, X-radiation of the reaction mixture and / or radioactive radiation.

33. The method according to any one of the preceding claims, characterized in that the direct heating takes place at least partially by an inductive heating of the reaction mixture.

34. The method according to claim 33, characterized in that the inductive heating is supported by adding a conductive medium.

35. The method according to claim 34, characterized in that the added to support the inductive heating conductive medium is separated later again.

36. Method according to claims 33 to 35, characterized in that the conductive medium added to support the inductive heating has a solid, particulate phase, in particular a metallic material.

37. The method according to at least one of the preceding claims, characterized in that the direct heating of the reaction mixture is at least partially by addition of a chemically inert, overheated component.

38. The method according to claim 37, characterized in that the chemically inert, overheated component is present in a particulate phase, in particular in the form of a metallic solid.

39. The method of claim 37 to 38, characterized in that the chemically inert component is separated later again.

40. The method according to at least one of claims 37 to 39, characterized in that the separated, chemically inert component is reheated to a higher temperature than the reaction temperature and re-used for direct heating in the at least one heating stage (Cl).

41. The method according to at least one of the preceding claims, characterized in that the direct heating is combined with an indirect heating by heated apparatus surfaces in the at least one heating stage (Cl).

42. The method according to any one of the preceding claims, characterized in that a premix of the educts in already preheated state, but still significantly below the reaction temperature in the at least one heating stage (Cl) occurs where the further heating takes place by means of direct heating.

43. The method according to any one of the preceding claims, characterized in that the at least one heating stage (Cl) comprises at least one agitator and / or at least one static mixer and / or at least one jet mixer and / or at least one jet pump.

44. The method according to claim 43, characterized in that the agitator is filled so far with the reaction mixture that there is no appreciable gas space above the reaction mixture and no liquid level is formed.

45. The method of claim 43 to 44, characterized in that at least one stirring element is designed as a gassing stirrer.

46. The method according to at least one of the preceding claims, characterized in that the volume of the at least one heating stage (Cl) is dimensioned such that when using solid in suspension present educts in the premix, these starting materials on leaving the at least one heating stage (Cl ) have largely gone into solution.

47. The method according to at least one of the preceding claims, characterized in that the

Reaction mixture is further treated after passing through the heating stage in a first region of the residence time, in which the use of suspended solid starting materials possibly not yet dissolved residues are operationally controlled by deposits of undissolved radicals is prevented by means of vertical flow control or increased flow rate or in their consequences by a particularly easy accessibility for cleaning or replacement measures are made manageable.

48. The method according to at least one of the preceding claims, characterized by at least one residence time (2, C2), which is connected downstream of the at least one heating stage (Cl), wherein the at least one further stage comprises a heat exchanger, so that 10

a temperature control or temperature maintenance of the reaction mixture is achieved via the surface.

49. The method according to at least one of the preceding claims, characterized in that at least one stage, in particular that which is connected downstream of the at least one heating stage (Cl), is designed as a tubular reactor.

50. The method according to claim 49, characterized in that individual sections of the tubular reactor can be bridged in order to reduce the reaction volume.

51. The method of claim 49 or 50, characterized in that the tubular reactor is constructed in the manner of a Rohrbündelwärmeübertragers, the individual pipe sections but essentially have a serial interconnection.

52. The method according to at least one of claims 49 to 51, characterized in that a partial flow between at least two areas of the tube reactor through a bypass and / or pipe sections is guided in a targeted parallel to influence the residence time distribution of the reaction mixture targeted.

53. The method according to at least one of the preceding claims, characterized in that at least a partial stream between two stages and / or subregions of stages is recirculated to selectively influence the residence time distribution.

54. The method according to at least one of the preceding claims, characterized in that a fully mixed zone is selectively increased compared to other areas in the stages in order to influence the residence time distribution targeted. 11

55. The method according to at least one of the preceding claims, characterized in that the flow is selected in at least one stage so that the present Reynolds number is above the critical Reynolds number and a turbulent flow prevails.

56. The method according to at least one of the preceding claims, characterized in that the viscosity profile of the reaction solution in

Reaction progress under similar conditions is measured in advance in a reaction viscometer or in a model experiment or calculated from known material data and the dimensioning of the tube sections with supercritical Reynolds number is achieved with optimized pressure losses by larger pipe diameters are selected in areas where lower viscosities occur, and vice versa.

57. The method according to at least one of the preceding claims, characterized in that at least one stage, in particular a tubular reactor, has internals, which slow down the flow velocity in the center of the pipe and increase in the edge region.

58. The method according to claim 57, characterized in that the internals have perforated plates mounted perpendicular to the flow direction, which slow down the flow in the interior due to a reduced density and / or size of the attached holes and which have a relatively higher permeability for the fluid in the outer region.

59. The method according to claim 57 or 58, characterized in that the number of internals is selected and the internals are distributed over the run length of the stage, in particular of the tubular reactor, that the 12

hydraulic residence time distribution of the residence time distribution approximates a plug flow.

60. The method according to at least one of the preceding claims, characterized in that in a first region of the cooling step, an evaporation takes place in which a substance or a mixture of substances evaporates under pressure reduction from the resin solution and heat is removed as a result of the evaporation enthalpy of the resin solution consumed.

61. The method according to claim 60, characterized in that the evaporating substance consists mainly of the solvent used.

62. The method according to at least one of the preceding claims, characterized in that at least one region of the at least one cooling stage, at least one pressure-holding valve or pressure regulator are arranged, which hold the operating pressure of the respectively upstream regions and stages above the boiling pressure of the reaction mixture or the resin solution.

63. The method according to at least one of the preceding claims, characterized in that behind the at least one residence time at least one pressure holding valve or pressure regulator are arranged, which keeps the operating pressure of the respective upstream regions and stages above the boiling pressure of the reaction mixture.

64. The method of claim 62 to 63, characterized in that the control or pressure holding valve dead space, in particular as a pinch valve is formed.

65. The method according to at least one of the preceding claims, characterized in that at least one cooling step is substantially tubular. 13

66. The method according to claim 65, wherein the tube cross-section of the at least one tubular cooling stage increases with decreasing temperature and increasing viscosity of the resin solution, so that an excessive pressure loss is avoided.

67. The method of claim 65 to 66, characterized in that the tube cross-section is relatively narrow in the first region of the tubular cooling stage, so initially under turbulent as possible

Flow conditions a particularly intense heat exchange is possible.

68. The method according to claim 67, characterized in that in the first tubular cooling stage turbulent flow conditions are ensured by dimensioning the tube diameter with supercritical Reynolds number, which is based on a previously determined viscosity profile of the resin solution during the cooling process.

69. The method according to at least one of the preceding claims, characterized in that the at least one cooling stage comprises static mixing elements.

70. The method according to at least one of the preceding claims, characterized in that at least one cooling stage and / or several of their tubular regions are formed in the manner of a double tube heat exchanger and / or in the manner of a tube bundle heat exchanger.

71. The method according to any preceding claim, characterized in that all conveying members are arranged in the flow direction before the at least one heating stage (Cl). 14

72. The method according to any preceding claim, characterized in that when starting the cold plant, this is wholly or partially operated with a solvent until reaching a certain starting temperature.

73. The method according to claim 72, characterized in that the solvent used for starting is a polyhydric alcohol, in particular polyethylene glycol.

74. The method according to at least one of the preceding claims, characterized in that when starting the cold plant initially in at least one stage a starting temperature is maintained, which is below the reaction temperature for the production of the product.

5. A method according to claim 74, characterized in that the said starting temperature is selected so that a particular quality of the resin is stable or can be generated in the first reaction zone, which has a particularly high solubility in the solvent used for starting.

76. The method according to claim 75, characterized in that the generation of the resin of particularly soluble quality during the startup in the heating stage is done intermittently discontinuous operation, while the start of the remaining stages is carried out by operation with the solvent.

77. The method according to at least one of the preceding claims, characterized in that prior to or during the start-up resin of particularly soluble quality in one or more areas of the system is added.

78. The method according to at least one of the preceding claims, characterized in that the preparation 15

a precondensed resin solution is at least partially carried out in a batch reactor as at least one reaction zone, wherein the reactor passes through individual process stages in a cycle and is filled with educts in a filling stage, then next to other possible stages a heating stage, in particular with a direct heating, a residence time and goes through an emptying stage.

79. The method according to claim 78, characterized in that the reaction is carried out above the boiling pressure of the reaction mixture.

80. The method of claim 78 or 79, characterized in that the starting materials supplied in the filling stage wholly or partially present as a premix, in particular as pre-heated premix.

81. The method according to at least one of claims 78 to 80, characterized in that for the compensation of heat losses or for setting a temperature profile, a heat exchange via heat exchange surfaces takes place.

82. The method according to at least one of claims 78 to 81, characterized in that between the residence time and the discharge stage, a process stage takes place, in which the reaction medium is cooled.

83. The method according to at least one of claims 78 to 82, characterized in that the cooling is only a pre-cooling of the resin solution, which undergoes after its emptying from the reactor further cooling in a subsequent container. 16

84. The method according to claim 83, characterized in that the precooling is wholly or partially effected by a flash evaporation, which is brought about by a reduction of the operating pressure in the reactor.

85. The method according to at least one of claims 78 to 84, characterized in that the method is operated with a suitable solvent, which has a sufficiently high vapor pressure, so that evaporates in the flash evaporation largely pure solvent.

86. The method according to claim 85, characterized in that it is the solvent is water, and a resulting, u. U. little contaminated steam can be released to the atmosphere.

87. The method according to claim 84 or 85, characterized in that the vapor discharged during the flash evaporation is treated in a condenser.

88. The method according to at least one of claims 84 to 87, characterized in that the vapor discharged during the flash evaporation is treated by blowing into a template with pre-cooled liquid, where it condenses.

89. The method according to at least one of claims 84 to 88, characterized in that the amount of liquid evaporated from the reactor is replaced by the supply of liquid, so that the level in the reactor during the pre-cooling remains substantially constant. 17

90. Device which serves as at least one heating stage for carrying out a method according to at least one of claims 1 to 89,

marked by

at least one fumigant for the introduction of a gas or a vapor for the direct heating of at least one liquid and / or a suspension and a stirrer with at least one agitator, wherein the at least one agitating by substantially radially arranged blades or flow channels promoting with respect to the at least one liquid and / or suspension is.

91. Apparatus according to claim 90, characterized in that the agitator has at least one guide tube, which is the place where the conveyed by at least one stirring body liquid and / or suspension is sucked, as far away from the stirring body that an intensive circulation of from the stirring body promoted suspension and / or liquid over the entire contents of the stirred tank can be generated.

92. Apparatus according to claim 90 or 91, characterized in that the gassing of the liquid and / or suspension takes place fine bubbles with a vapor which flows under pressure into the liquid and / or suspension, condenses there and heated via the thereby released evaporation enthalpy the liquid ,

93. Device according to at least one of claims 90 to 92, characterized in that the supply of liquid or suspension takes place from below in the manner and 18

Bottom of the stirring element is flown, so that there can form no gas cushion.

94. The device according to at least one of claims 90 to

93, characterized in that the gas or steam is supplied to the stirring member via a hollow shaft.

95. The device according to at least one of claims 90 to

94, characterized in that the steam is fed via separate supply lines to the at least one stirring body, which ends approximately in the middle just above or just below the Rührkörperoberfläche.

96. The device according to at least one of claims 90 to

95, characterized in that the steam is fed via separate supply lines to the at least one stirring body, which ends laterally on the circumference of the stirring body just next to the Rührkörperoberfläche.

97. The device according to at least one of claims 94 to

96, characterized in that the ends of the feed lines for the supply of steam are formed as a nozzle system.

98. Device according to at least one of claims 94 to

97, characterized in that gas or steam exits through corresponding outlet bores from the at least one stirring body.

99. Apparatus according to claim 98, characterized in that outlet bores are arranged on the underside, the top and / or on the circumference of the at least one stirring body.

100. The device according to at least one of claims 94 to 99, characterized in that the quantitative ratio of the at the top, at the bottom and / or by the periphery 19

outgoing steam is controlled via an adjustable distribution system.

101. The device according to at least one of claims 94 to

100, characterized in that outlet bores are mounted on the rear side in the direction of rotation of the conveying-effective blades.

102. The device according to at least one of claims 90 to

101, characterized in that the expansion of the stirred tank in the axial direction is sufficiently small, so that there is an intensive circulation of the promoted by at least one stirring or suspension suspension in the entire volume of the stirred tank, without the need for a guide tube.

103. The device according to at least one of claims 90 to 102, characterized in that the flow leaving the stirring member is guided so that in the stirred tank two zones arise between which there is a relatively low convective mass transfer.

104. Apparatus according to claim 103, characterized in that the formation of the zones is supported by the installation of an annular guide on the inside of the agitator at the level of the stirring member.

105. Apparatus according to claim 104, characterized in that the guide consists of the brims of two dished ends, which are placed on each other at their smaller diameter and welded.

106. The device according to at least one of claims 94 to 105, characterized in that the stirring member in the manner of a blade or Scheibenrührers consists of a horizontally mounted, rotating disc, at the in 20

Essentially radially extending delivery-effective blades are mounted.

107. Apparatus according to claim 106, characterized in that the blades are arranged on the underside of the disc and / or on the upper side of the disc.

108. Apparatus according to claim 106 or 107, characterized in that the blades are closed on the top with a round cover plate having an inlet opening in its center.

109. The device according to at least one of claims 90 to 108, characterized in that the agitator is designed as a batch reactor.

110. The device according to at least one of claims 90 to 109, characterized in that the agitator has at least one agitator on which takes place at pressure reduction, a degassing, which is used for rapid cooling of the Rührwerkinhalts.

111. The device according to at least one of claims 90 to

110, characterized in that the at least one stirring body, at which the degassing takes place, is located just below the surface of the adjusting itself in its operation Trombe.

112. The device according to at least one of claims 90 to

111, characterized in that at least one agitator of the gassing stirrer is identical to at least one effective at a corresponding pressure reduction for the degassing agitator. 21

113. The device according to at least one of claims 90 to

112, characterized in that at least one stirring body of the gassing stirrer is arranged in the lower part of the agitator.

114. The device according to at least one of claims 90 to

113, characterized in that the agitator comprises a heatable or coolable jacket and / or a heatable or coolable tube coil over which its contents can be tempered.

115. The device according to at least one of claims 90 to 114, characterized in that the agitator has on its lid a dome, can be deducted largely free of liquid over the resulting vapor.

116. Device according to at least one of claims 90 to 114, characterized in that the agitator comprises baffles.