DE10123002C1 - Reaction apparatus for the production of reaction plastics - Google Patents

Abstract

The invention relates to a reaction apparatus for the production of reaction plastics, consisting of a combination of two independently working, self-cleaning twin-screw extruders which are connected to one another at the screw end housings without dead space.

Description

The invention relates to a reaction apparatus for production of reaction plastics, in particular polyurethanes, and the production of reaction plastics, especially poly urethanes, by means of this reactor.

Reaction plastics in the sense of the invention include such Understand plastics that by chemical reaction of min at least two components are produced. To be favoured such reaction with the reaction apparatus according to the invention Made of plastics that have thermosetting properties exhibit. Taking thermosetting properties is said to mean of the present invention can be understood that art substances are no longer meltable after curing. The duro plastic properties are particularly through networking caused.

To the preferred with the reactor of the invention Reactive plastics that can be produced belong in addition to the chemical ones cross-linked polyurethanes, such as hard and soft and semi-hard foams, cast elastomers and reactive systems, for example also amino and phenoplasts, silicone elastomers, unsaturated Polyester resins and epoxy resins.

The polyurethanes, and here in particular the polyurethane foams, are of particular importance among the reaction plastics. The polyurethanes are usually produced by reacting at least one polyisocyanate with at least one compound having at least two hydrogen atoms reactive with isocyanate groups, in the production of foams in the presence of blowing agents. The reaction components are mixed and then allowed to harden into foam. Special mixing elements, for example mixing heads, are generally used for mixing. Such units have been described many times, for example in the plastics manual, volume 7 "Poly urethane" 1st, 2nd and 3rd edition, Carl-Hanser-Verlag Munich.

WO 96/20966 A1 describes a process for the production of poly urethane foams described in which the reaction components are mixed together in an extruder and after their discharge on a tape, for example one ago conventional double belt, lather and harden. Because of this The method is intended in particular to incorporate fillers into  the foam will be relieved. According to the teaching of WO 96/20966 A1 at least 15 to 20 wt .-% fillers in the foam be incorporated. One or two shafts are used as extruders extruder described, it being the twin-screw extruders is about co-movement.

However, it has been shown that using this method only Processed polyurethane systems with an extremely long setting time because otherwise there will be deposits in the extruder, which can lead to the foaming of the extruder. Also comes there are strong pressure fluctuations in the extruder. In WO 96/20966 A1 it is pointed out that rigid foams in which already in the extruder the polyurethane formation takes place, to block of the extruder.

Research Disclosure 402064 describes a manufacturing process of rigid polyurethane foams described in the Polyiso cyanate, polyol, blowing agent and catalyst in an extruder introduced in this up to a turnover of 5 to 50% implemented and this reaction mixture through a nozzle on Band is discharged where it turns into a polyurethane foam reacts and foams. The pressure at the nozzle should be high enough to cause premature foaming or segregation to avoid the reaction mixture. Even with this procedure the urethane formation reaction takes place essentially outside of the extruder.

Problematic in the production of reaction plastics, in particular thermosetting reaction plastics, by means of Extrusion is the irreversible formation of solid, not fusible reaction products within dead zones of the Extruder, especially near the outlet of the Extruder. These deposits can cause problems with Pressure build-up inside the extruder and in extreme cases Blockage of the extruder coming.

The object of the invention was to provide a method for Production of reaction plastics by means of extrusion to develop a process in which a constant pressure build-up in the Extruder takes place and the irreversible formation of solid Reaction products in dead space areas of the extruder prevented becomes.

The task could surprisingly be solved by as Reactor a combination of two independently working self-cleaning twin-screw extruders  the dead space free at the screw end housings with each other are connected.

The invention accordingly relates to a reaction apparatus for the production of reaction plastics, consisting of a Combination of two independently working self cleaning twin screw extruders, which can be Screw end housings are interconnected.

The invention further relates to a method for the manufacture position of reaction plastics, preferably polyurethanes, especially polyurethane foams, in one reaction apparatus with the features of claim 9.

The extruders can be connected in a known manner. Preferably this second extruder is connected to the twin screw extruder flanged counter-rotating screws.

The counter-rotating screws in which the output components of the reaction plastics filled and for Reaction are served because of their stronger axial sealing of the pressure build-up in the extruder. this part of the extruder is therefore the reaction mixture first run through.

The co-rotating screws mainly have a pressure regulating one and product carrying function.

The pressure regulating function of the co-rotating screws can preferably by a specific loading of the snails with promoting and counter-promoting screw elements and by Vary the screw speed.

The product-carrying function of the synchronous screws takes place mainly due to a product jam in the area of a degassing Zone. This product jam can be caused, for example, by a leak closing baffle plate on the worm shafts.  

The opening of the degassing zone mostly becomes at the same time Product discharge used. It is usually below of the reaction apparatus in the direction of the center of gravity. This can be done in simplest case would be an opening. However, it is also possible Lich, the discharge differently, for example, as a form adaptation, embody.

The extruder part with co-rotating screws that the Product flow from the counter rotating twin screw extruder forcibly handed over, depending on the direction of funding the screw elements used, the screw speed, the Configuration of the screws or similar parameters from the counter-rotating extruder part to be overcome conveying decrease or increase resistance. This is the on the Reaction mass pressure reduced or increased. This Pressure can, for example, by varying the speed of the twin-screw extruder can be precisely regulated.

As stated, there is for the design of the transition from Twin screw extruder with counter rotating screws for double screw extruder with co-rotating screws different Possibilities.

So it is possible that the screws of both extruders are the same Have the conveying direction, but the speed of the twin screw extruder with counter-rotating screws is higher than that of the Twin screw extruder with co-rotating screws. Already This simple measure can cause pressure to build up be, the formation of coverings by the dead space-free Arrangement with known ability of the twin snails to self cleaning is prevented.

In a preferred embodiment of the invention Reaction devices have the snails of the two doubles screw extruder on an opposite direction of conveyance. This is achieved by a snail conveying to the right trimmed mirror image of the counter rotating screw extruder opposite arranged twin screw extruder. So get normal, that is, right, promotional snail elements a counter-promoting, i.e. congestion, function. A trim with return-promoting, that is, left-promoting, elements would through the mirror image arrangement has a promoting function.

In a particularly preferred embodiment of the invention according to the reaction apparatus, the twin-screw extruder has co-rotating screws at the transition from the twin screw extruder with counter-rotating screws initially right-hand screw elements  and then left-hand screw elements. This results in the transition between the two twin screw extruders first to a product jam and thus to the desired Pressure build-up. Due to the constant supply of products from the opposite direction rotating twin screw extruder, this section with the run over right-hand screw elements. By yourself to the left, to the right-conveying screw elements the reaction mixture is further promoted by screw elements transported to the discharge of the reaction apparatus. In addition to the ver This embodiment of the invention has improved pressure build-up according reaction apparatus the further advantage that it is in the over the right-hand auger elements move in addition to one even better mixing of the reaction mixture comes.

It is also possible in principle, the snails of the double screw extruders with co-rotating screws with several successive screw elements with different Equip the conveying direction if necessary. benefit Such an arrangement appears to be imprudent if one passes through On binding of mixing elements an improved mixing of supplied additives, for example catalysts wants, that is, a sequentially promoting, mixing and stagnating screw geometry required.

To carry out the method according to the invention, the Starting materials for the production of the reaction plastics, as stated above, in the twin screw extruder dosed with opposing screws.

It is possible to use all raw materials for the plastics to dose in one place. This can be done before Dosage to be mixed. This can be done in common and well known Mixing elements, for example in the production of polyurethanes wise by means of mixing heads.

It is also possible to use the individual starting materials for the Plastics at different points in the reaction apparatus to dose. It is also possible to use individual components premix into the reactor prior to dosing.

Preferred group of reaction plastics, which according to the Processes according to the invention can be produced Polyurethanes. The polyurethane Foams, as these have an increased tendency to become irreversible Show formation of solid reaction products. The Her These connections are known to be made by Reaction of polyisocyanates with compounds with at least  two hydrogen atoms reactive with isocyanate groups. This The reaction mostly takes place in the presence of catalysts, propellants means and, if necessary, other auxiliary and / or Additives.

In the production of polyurethanes with the invention Reactor it is also possible to use the starting materials separately or together to feed the reactor.

Catalysts, blowing agents and auxiliaries and / or additives can the polyisocyanate and / or the compounds with at least two hydrogen atoms reactive with isocyanate groups before Dosing can be added to the reactor.

It is also possible to use the catalysts, blowing agents and the other auxiliaries and / or additives separately from one Bring reactor upstream mixing device and there with the polyisocyanate and / or the compounds at least two hydrogen atoms reactive with isocyanate groups to mix. It is also possible to use the compounds mentioned to the reaction apparatus separately from the reaction components drive. The dosage can be the same or different Zone are made in which the polyisocyanates and Compounds with at least two reactive with isocyanate groups Hydrogen atoms were dosed. It is also possible to have one Part of the components mentioned before entry in the reaction apparatus to add the reaction components and another Part separately from the reaction components of the reactor fully close. So it can be beneficial to use certain additives and fillers, but also catalysts and / or blowing agents in the extruder with the counter-rotating screws upstream of the Add the reaction components.

In a preferred embodiment of the invention Polyisocyanate, the compounds with at least two with Iso hydrogen atoms reactive to cyanate groups and, if used, the blowing agent, especially water and / or physical Propellant, with a mixer, preferably a low pressure Mixer, or mixed by a low pressure mixing system, this Mixture fed to the reactor and the catalyst ent neither before or in the mixer, or in any later Zone after the mixer and before the outlet organ after the reaction apparatus is fed. Additionally used auxiliary and / or Additives can, as described above, both together with the polyisocyanate and / or the compound with at least two with Isocyanate reactive hydrogen atoms as well in one any zone both before the mixer feed and between  this and the outlet member fed to the reaction apparatus become.

In general, the zone in which the reaction mixture prevails is entered, no pressure yet. This is only in the zones built up that connect downstream to this zone.

As already mentioned, the reaction apparatus according to the invention consists of two arranged in mirror image to each other and free of dead space Twin-shaft extruders, an opposing twin-screw extruder for taking up the reaction components and additives and as pressure constructive reaction system, and a synchronous double screw extruder, depending on the desired design of the Process for controlled back pressure build-up through training a corresponding funding resistance and / or for improvement the mixing and discharge effect optionally with promoting, against promoting, mixing and kneading elements.

The twin screw extruder with counter rotating screws is preferably from up to 7 housing parts with a ratio from length to diameter (L / D ratio) from 3.5 to 28 built in which the inclusion of additives and fillers that Supply of reaction components and reaction accelerators, mixing, reaction and pressure build-up in the downstream lying order. The loading with fixed Additives and fillers are made especially through open ones Addition points, the supply of the liquid reaction components, Reaction accelerators and additives can be open or under closed conditions. Find use due to preferred their high self-cleaning and sealing effect wise tightly intermeshing screw elements that are in the area of addition make high screw pitches to have no backwater to be able to absorb the raw materials supplied. To build up pressure downstream, screw elements with decreasing preference are preferred Slope used. The screw speeds caused by the Throughput, the desired dwell time and the intended one Pressure build-up are usually between 20 and 250 / min, preferably at 50 to 200 / min. The twin screw extruder with co-rotating screws, the mirror image dead space-free at the outlet part of the twin screw extruder with counter Common snails is attached, is preferably from 1 to 5 housing parts with an L / D ratio of 3.5: 20. It can be rotated both left and right his. It is preferably used in a left-handed rotation. By Stocking with promoting, counter-promoting or mixing and kneading screw elements can a dewing, d. H. against pressure generating, or also promoting or mixing and kneading  Effect can be achieved. In addition, this fulfills double screw extruder also the task of product discharge, the preferably via a degassing opening in the direction of gravity is taken. A further transport of the reaction mass in the direction Snail shaft is through one with the end of the degassing closing baffle plate reached. A preferred one Arrangement of the screw elements to achieve an initial Pressure build-up with subsequent mixing of an example wise supplied catalyst portion with final product The result is the establishment of in the sense of the synchronous principle promoting elements at the transition to the counter-rotating screw, then following the construction of screw mixing elements and / or kneading blocks and finally the installation of in the sense of Synchronization principle counter-promoting elements in the upstream direction the synchronous twin screw. The increase in delivery resistance by counter-funding in the product transition area from against running to co-rotating twin screw causes one additional pressure build-up, due to the speed variation of the double screw extruders can be regulated with co-rotating screws can.

The screw geometry itself and its sequential arrangement in the area of the co-rotating twin screw is corresponding of the procedural task selectable. The screw speeds of the Synchronous extruder part can be selected and lie independently in the range of 10 and 400 / min, preferably at 30 and 300 / min.

When using the reaction apparatus according to the invention It is surprising that the production of reaction plastics possible, even those plastics that lead to irreversible formation of solids, such as polyurethane foams, to produce without causing a deposit in the reactor comes from irreversibly hardened components.

The pressure in the reactor can be easily adjusted and keep it constant. The reaction apparatus can also do this be operated stably and reliably over long periods. Surprisingly, according to the invention Processed plastics, especially the poly urethane foams, better properties than those on, which were produced by conventional methods, such as is explained in more detail below.

Preferably in the manufacture of plastics, ins special polyurethane foams, according to the invention Process the reaction mixture in the reactor as far below Pressure set or held that it foams there under pressure build-up  or the blowing agent physically or chemically dissolves or in at least one zone downstream of the dosage the reaction mixture is metered so that the reaction mix very quickly after discharge from the reactor relaxed, foaming quickly, and mostly just cures. This is achieved by the reaction mixture shortly before the setting time, in particular a few seconds before the Setting time from which the reaction apparatus is discharged. A Volume increases depending on the bulk density of the foam 5 to 1000 times, preferably 12 to 60 times and in particular 20 to 40 times. The volumes Magnification is based on the unfoamed mixture, that is a compact polyurethane made from the same feed materials, however without blowing agent.

The reaction mixture is thus on exiting the reaction apparatus essentially reacted, that is, foaming after extrusion is essentially physical Process. This process of essentially temporal of the Urethane formation reaction, separate foaming of the reaction Mixture is often referred to as Froth.

As stated, the pressure in the reactor is above that Atmospheric pressure. It is preferably during production of polyurethane foams above 10 bar, in particular between 10 and 200 bar, particularly preferably between 10 and 100 bar. The pressure in the reactor should not be 200 bar exceed. The overpressure arises during manufacture of polyurethane foams from which by reacting with Water generated carbon dioxide and / or by evaporating physical blowing agent, especially physical blowing agent medium, which tries to inflate the reaction mixture, but is prevented by the reaction apparatus and thus pressure generated, and / or by screw compression of the reaction system troubles.

The temperature in the reactor should not exceed 200 ° C climb. Is preferred, depending on the type of plastic Temperature range from 20 to 150 ° C, especially from 20 to 100 ° C, worked. The reaction is at higher temperatures difficult to control, at lower temperatures can the reaction of the reaction mixture upon exit from the Reaction apparatus not yet advanced enough secondly, the viscosity of the reaction mixture is very high high.  

As stated, the reaction mixture preferably comes fully reacted, but still flowable from the discharge of the reaction apparatus and only has to harden and in the case of foams, lather. This allows the Foam without the otherwise necessary overfilling or with clearly lower overfill into the molds or cavities become, which leads to a further reduction in density and thus to a further material saving as well as an equal leads to more moderate density distribution in the foam. Demoulding too times in the production of moldings can be reduced.

Preferably, according to the inventive method provided rigid polyurethane foams as sheets or can be used to fill cavities.

According to the inventive method, as stated, in principle all types of reaction plastics, preferably thermosetting plastics and especially polyurethane Foams. It is particularly advantageous the application of the method according to the invention position of rigid polyurethane foams, especially those which are used for thermal insulation.

It has surprisingly been found that after the invention Rigid polyurethane foams produced in accordance with the process same cell size have thicker cell walls than those were produced by other processes. Usual cell wall thicknesses amount to 0.5 µm and below, resulting in web portions in the foam matrix of over 90% leads. By the method according to the invention it was surprisingly possible to use foams with wall parts of greater than or equal to 10%. The cell sizes of the Foams according to the invention are usually significantly lower than that of foams with the same formulation, which according to conventional processes were produced. That affects Poly Rigid urethane foams are very favorable on thermal conductivity and the mechanical properties, especially the compressive strength, out.

Using in the manufacture of the reaction plastics of the reaction apparatus according to the invention for the Her position of the respective plastics necessary input materials used. This is to be exemplified in the following during production be described by polyurethanes.  

Among those in the preferred manufacture of polyurethane foam substances used by the inventive method Starting compounds can be said in detail as follows.

The usual aliphatic, cyclo aliphatic and especially aromatic di- and / or poly isocyanates for use. Toluene is preferably used diisocyanate (TDI), diphenylmethane diisocyanate (MDI) and ins special mixtures of diphenylmethane diisocyanate and poly phenylene polymethylene polyisocyanates (raw MDI). The isocyanates can also be modified, for example by installing Uretdione, carbamate, isocyanurate, carbodiimide, allophanate and especially urethane groups.

For the production of rigid polyurethane foams, ins special raw MDI used. For different applications it is advantageous to include isocyanurate groups in the polyisocyanate install.

Isocyanurate groups are preferred for this purpose Catalysts, for example alkali metal salts, such as potassium octoate and / or potassium acetate alone or in combination with tertiary Amines used. The formation of isocyanurate leads to flame retardant Foams, which are preferred in technical rigid foam, for example in construction as an insulation board or sandwich elements, be used. Isocyanurate formation can occur at temperatures drain more than 60 ° C.

Compounds with at least two groups reactive toward isocyanate, that is to say with at least two hydrogen atoms reactive with isocyanate groups, are in particular those which have two or more reactive groups selected from OH groups, SH groups, NH groups, NH ₂ groups and CH-acidic groups, such as. B. β-diketo groups in the molecule.

To manufacture the before according to the inventive method Rigidly produced rigid polyurethane foams come into play special compounds with 2 to 8 OH groups are used. Polyetherols and / or poly are preferably used esterole. The hydroxyl number of the polyetherols used and / or Polyesterole is used in the production of polyurethane hard foams preferably 100 to 850 mgKOH / g, especially before add 200 to 600 mgKOH / g, the molecular weights are preferred larger than 400. The polyurethanes can be with or without chains extenders and / or crosslinking agents are produced. As chain extenders and / or crosslinking agents come into special bifunctional or trifunctional amines and alcohols, in particular  Diols and / or triols with molecular weights smaller than 400, preferably from 60 to 300, are used.

Water is used in particular as a blowing agent. On Instead of or in a mixture with water, so-called physical blowing agents are used. Including ver there are compounds in the feedstocks of the poly urethane production are dissolved or emulsified and among the Evaporate conditions of polyurethane formation. This is what it is about are, for example, hydrocarbons, halogenated coals hydrogen, and other compounds, such as by fluorinated alkanes such as perfluorohexane, chlorofluorocarbons substances, as well as ethers, esters, ketones and / or acetals. Is next to it it is possible to use inert gases such as nitrogen, carbon dioxide or noble to release gases under pressure in the polyurethane components.

The usual catalysts, auxiliaries and / or Additives are used.

Fillers are either attached, i.e. as a paste, or as a liquid dispersion in the polyol or isocyanate component stirred in, or directly via dispersants of the reaction mix fed. Another preferred variant of the The filler is introduced via an upstream before the feed Opening of the reaction mixture located housing opening. Fillers which can be used are preferably those which lead to increased flame resistance, for example, ammonium polyphosphate, expanded graphite, but also those used for lowering thermal conductivity, for example IR-absorbing Substances such as carbon black, graphite, aluminum powder or metal organic compounds.

Tertiary amines, tin Catalysts or alkali salts are used. There is also Possibility to run the reactions without catalysis. The reaction is carried out by the screw rotation registered, or formed by the exothermic reaction external heat activated.

More detailed information on the above and other starting materials can be found in the specialist literature, for example the Plastics Manual, Volume VII, Polyurethane, Carl Hanser Verlag Munich, Vienna, 1st, 2nd and 3rd editions 1966 , 1983 and 1993 .

Due to the described configuration of the invention Reactor it is possible to have one in the reactor maintain constant pressure. By design  of the reactor according to the invention in the form of two their basic principle promoting self-cleaning against each other Twin screw extruders with a dead space free arrangement of controlled product damming and thus pressure build-up serving in the same direction rotating twin-screw extruder one in contrast to the known, a flow resistance generating techniques that narrow the flow cross-section, for example, capillary nozzles or throttle systems, extensive Freedom from irreversible and process continuity limiting product deposits guaranteed. The pressure ratios and the residence time of the reaction mixture in the Extruders are easily adjustable, so that a change in the para meters is possible without extensive extruder conversions.

The art produced by the method according to the invention fabrics can be used for the usual and well-known areas be used.

So can be produced by the inventive method Flexible polyurethane foams, in particular as seat cushions in the Furniture area, as mattresses or for similar applications be set. The according to the inventive method posed rigid polyurethane foams can in particular thermal insulation, for example of refrigeration units, district heating pipes, Pipe insulation, heat storage, in vacuum insulation, or in Construction, for example for sandwich elements or insulation boards, be used. The according to the inventive method Semi-rigid foams can be used especially in automobiles area, for example as energy absorbing foams for Door linings, protective pads in the interior, headlining for Sound insulation or used for similar applications. The cellular cells produced by the process according to the invention Polyurethane elastomers can preferably be used as vibration dampers be used in vehicles.

More detailed information on the above and other uses of the reaction plastics according to the invention are in the specialist literature, in the case of polyurethanes for example the plastics handbook, Volume VII, Polyurethane, Carl Hanser Verlag Munich, Vienna, 1st, 2nd and 3rd edition 1966 , 1983 and 1993 .

The invention is described in more detail in the following examples become.  

example 1 reactor

The reactor, which is shown in Fig. 1 in top view and in Fig. 2 in the side view, consists of a synchronized and a mating embodiment of a laboratory twin screw extruder type LSM 30/34, Leistritz, with a screw diameter of 34 mm and a Total screw length of 31.5 × D (9 zones) in the composition of the single screw lengths of 7 × D, which corresponds to 2 zones ( 1 and 2 ) of the synchronous part to 24.5 × D, which corresponds to 7 zones, of the counter-rotating part ( 3 to 9 ) with a length per zone of 3.5 × D. D means screw diameter. The combination itself takes place free of dead space at the respective outlet ends of the extruder parts through a flange ( 10 ). The two almost touching screw pairs, 11 and 12 counter-rotating, 13 and 14 counter-rotating, are freely adjustable at different speeds due to separate drive units, the maximum adjustable screw speeds are 400 / min for the co-rotating screws or 300 / min for the counter-rotating screws , The direction of rotation is counter-clockwise for the co-rotating or left / right for the counter-rotating screws. The extruder zones can be electrically heated and cooled individually. Zone 5 of the extruder with counter-rotating screws ( 5 ) is designed to hold the liquid raw materials as a feed section with a filler neck ( 15 ), zone 2 of the synchronous section ( 2 ) is designed as a discharge section (degassing housing) with a discharge opening ( 16 ) in the direction of gravity. At the end of the discharge part ( 2 ) in the drive direction, the synchronous screws are provided with a baffle plate ( 17 ) in order to ensure forced delivery in the discharge direction. The screw set of the co-rotating screws was first determined in the flow direction with right-hand-conveying elements, ie, stagnating due to the mirror-image arrangement in the direction of the product flow, and subsequently with left-hand-conveying elements, ie in the product flow direction, conveying elements. The screw stocking of the screws running against is selected with tightly intermeshing conveying elements with a decreasing gradient in the conveying direction in order to build up pressure. In the area of the feed section zone 5 of the counter-run part ( 5 ), conveyor elements with a comparatively large slope are used in order to guarantee a good feed effect of the raw materials. Pressure measuring points are set up in the adjacent zones of the two extruder parts, ie in zone 7 ( 3 ) (also referred to as housing 7 of the counter-rotating twin-screw extruder) and zone 8 ( 2 ) (also referred to as housing 2 of the co-rotating extruder) in the product flow direction.

Example 2 Production of a microcellular, urea-containing polyurethane elastomer

A prepolymer with an NCO content of 4.25% by weight was placed in a raw material reservoir of a low-pressure foam machine. The prepolymer was previously prepared in a separate stirred kettle according to the following procedure:
100 parts by weight of a dehydrated linear polyether polyester polyol with a hydroxyl number of 56 mg KOH / g, which is a polycondensate of a short-chain polytetrahydrofuran with a molecular weight of 250 g / mol and adipic acid, were under with 24 parts by weight of naphthylene diisocyanate at 140 ° C. intensified homogenization reacted. The prepolymer was at a temperature of 80 ° C in a low pressure mixing head at a mixer speed of 2800 / min with a crosslinker component consisting of 28.1 wt .-% water and a mixture of a hydrolysis protection agent and emulsifiers in a ratio of 100 to 3.05 mixed and immediately metered into the feeder ( 15 ) of the reactor according to Example 1 with a total output of 14 kg / h. The temperature in the extruder was 80 ° C and the speed of the counter-rotating screws was 180 / min. In the extruder with co-rotating screws, which, in contrast to the extruder from Example 1, had a screw feed conveying and mixing exclusively in the product flow direction and a screw speed of 230 / min, were placed in a housing ( 2 ) (housing 8 in the product flow direction) Mixing zone 0.03 GT Desmorapid® PP injected as a catalyst. The reaction mixture was then pressed under a slight excess pressure of 1 to 5 bar into briefly closing molds docked onto the discharge opening 16 , which molds were opened after 30 minutes. After an interim storage period of at most 5 hours, the molded parts were annealed at 110 ° C. for 16 hours. The molded part, a 40 g spring element for additional damper systems in automotive engineering, had a more uniform cell structure and more homogeneous density distribution compared to conventional discontinuous manufacturing technology. Furthermore, due to its high level of self-cleaning, the twin-screw system allows largely continuous production and thus reproducible and uniform product quality.

Example 3 Production of a rigid polyurethane foam

The experiments were carried out in a reaction apparatus according to Example 1 with a rigid polyurethane foam system with the following composition carried out:

polyol

100 parts by weight of polyester alcohol, made from phthalic anhydride, diethylene glycol and monoethylene glycol (diethylene glycol: monoethylene glycol = 10: 1) with a hydroxyl number of 240 mg KOH / g and a viscosity of 12000 mPas at 25 ° C
12 parts by weight of butanediol

1

.

4

1 part by weight of stabilizer DC

193

from Air Products
1 part by weight of catalyst mixture consisting of the amine catalyst Lupragen® N600 from BASF Aktiengesellschaft (48.3 parts by weight); a polyol of propylene glycol and propylene oxide with a hydroxyl number of 250 mgKOH / g (22.5 parts by weight), triethanolamine (26.7 parts by weight) and glycerol (2.5 parts by weight),
3.5 parts by weight of water as a blowing agent

Isocyanate component consisting of partially carbodiimide groups containing 4,4'-diphenylmethane diisocyanate with an NCO content 29.5% by weight (Lupranat® MM103 from BASF Aktiengesellschaft)

The mixing ratio of polyol component to isocyanate component was 100: 119 parts by weight.

The following values were determined when the polyurethane system used was manually foamed in a cup:
Start time: 42 seconds
Setting time: 64 seconds
Rise time: 92 seconds
Bulk density: 47.4 g / l

At the discharge 16 of the extruder, the reaction mixture was filled into a beaker with a diameter of 11 cm and a height of 10 cm and a volume of 660 ml and allowed to harden there.

The bulk density of the cured foams was determined in accordance with DIN 53 420, the cell size in accordance with ASTM procedure 3576-77, the closed cell structure in accordance with ASTM D 2856-87 procedure B using Accupyc 1330 and the compressive strength in accordance with DIN 53421.

Claims (13)

1. Reaction apparatus for the production of reaction art fabrics consisting of a combination of two of self-cleaning double working independently screw extruders that have no dead space at the screw ends casings are interconnected. 2. Reactor according to claim 1, characterized in that that it comes from a twin screw extruder with counter rotating Screws on which a twin-screw extruder without dead space connected with co-rotating screws. 3. Reactor according to claim 1, characterized in that the screws of both extruders have the same conveying direction have. 4. Reaction apparatus according to claim 1, characterized in that the screws of both extruders have the same conveyance own direction and the speed of the twin screw extruder with counter-rotating screws is higher than that of the twin-screw extruder with co-rotating screws. 5. Reactor according to claim 1, characterized in that the screws of the two twin screw extruders have opposite conveying direction. 6. Reactor according to claim 1, characterized in that the screws of the twin screw extruder with the same running snails with promoting and counter-promoting Screw elements are equipped. 7. Reaction apparatus according to claim 1, characterized in that a degassing zone is used to discharge the product. 8. Reaction apparatus according to claim 1, characterized in that the degassing zone is below the reactor located in the direction of gravity.   9. Process for the production of reaction plastics, especially polyurethane foams, in one reaction apparatus, characterized in that as a reaction apparatus a combination of two working independently self-cleaning twin screw extruders is used, ver with each other at the screw end housings without dead space are bound with a twin-screw extruder running in opposite directions Screws and a twin screw extruder co-rotating Has snails, the starting materials of the art of reaction substances in the twin screw extruder with counter rotating Snails are dosed and the reaction products a product discharge, which is on the twin screw extruder with co-rotating screws. 10. The method according to claim 9, characterized in that the Screws of the twin screw extruder with counter rotating Screws and the twin screw extruder with the same running screws in opposite conveying directions to run. 11. The method according to claim 9, characterized in that the starting materials of the reaction plastics individually in the Twin screw extruder dosed with counter-rotating screws become. 12. The method according to claim 9, characterized in that the Starting materials of the reaction plastics premixed in the Twin screw extruder dosed with counter-rotating screws become. 13. The method according to claim 9, characterized in that the Reaction plastics are polyurethanes.