DE10130649A1 - Process for the production of composite elements - Google Patents

Abstract

The invention relates to a method for producing composite elements having the following layer structure: (i) 2 to 20 mm metal, plastic or wood; (ii) 10 to 300 mm plastic, (iii) 2 to 20 mm metal, plastic or wood. According to said method, the starting materials used for forming layer (ii) are poured in a liquid state into the space between (i) and (iii) and negative pressure is meanwhile generated in said space.

Description

• a) 2 mm bis 20 mm, bevorzugt 2 mm bis 10 mm, besonders bevorzugt 5 mm bis 10 mm Metall, Kunststoff oder Holz, bevorzugt Metall,
• b) 10 mm bis 300 mm, bevorzugt 10 mm bis 100 mm Kunststoff, bevorzugt Polyisocyanat-Polyadditionsprodukte
• c) 2 mm bis 20 mm, bevorzugt 2 mm bis 10 mm, besonders bevorzugt 5 mm bis 10 mm Metall, Kunststoff oder Holz, bevorzugt Metall,

durch Befüllen des Raumes zwischen (i) und (iii) mit flüssigen Ausgangskomponenten zur Herstellung von (ii), bevorzugt mit einer Reaktionsmischung enthaltend (a) Isocyanate und (b) gegenüber Isocyanaten reaktive Verbindungen zur Herstellung von (ii) Polyisocyanat-Polyadditionsprodukten. Die eingangs dargestellten Längenangaben zu den Schichten (i), (ii) und (iii) beziehen sich auf die Dicken der jeweiligen Schicht. The invention relates to methods for producing composite elements which have the following layer structure:

• a) 2 mm to 20 mm, preferably 2 mm to 10 mm, particularly preferably 5 mm to 10 mm metal, plastic or wood, preferably metal,
• b) 10 mm to 300 mm, preferably 10 mm to 100 mm plastic, preferably polyisocyanate polyaddition products
• c) 2 mm to 20 mm, preferably 2 mm to 10 mm, particularly preferably 5 mm to 10 mm metal, plastic or wood, preferably metal,

by filling the space between (i) and (iii) with liquid starting components for the production of (ii), preferably with a reaction mixture containing (a) isocyanates and (b) compounds reactive toward isocyanates for the production of (ii) polyisocyanate polyaddition products. The length specifications for layers (i), (ii) and (iii) shown at the beginning relate to the thicknesses of the respective layers.

For the construction of ships, for example ship hulls and cargo space covers, bridges, roofs or high-rise buildings Construction parts are used, the significant loads can withstand external forces. such Construction parts usually consist of these requirements Metal plates or metal supports through an appropriate Geometry or suitable struts are reinforced. So exist hulls of tankers due to increased Security standards usually consist of an inner and an outer Fuselage, each fuselage made of 15 mm thick steel plates that pass through approx. 2 m long steel struts are connected to each other, is constructed. Because these steel plates are exposed to considerable forces both the outer and the inner steel shell stiffened by welded-on reinforcement elements. adversely on these classic construction parts, both substantial amounts of steel that are needed as well the time and labor intensive manufacturing. Also point out such construction parts on a significant weight, which a lower tonnage of the ships and an increased Fuel requirement results. In addition, such are classic Construction elements on the basis of steel are very maintenance-intensive, since both the outer surface, as well as the surfaces of the steel parts between the outer and inner shell regularly against corrosion must be protected.

PLC elements are a replacement for the steel structures (Sandwich plate system) known, which is a composite of metal and Include plastic. Due to the adhesion of the plastic to the two metal layers create composite elements with extraordinary advantages over known steel constructions. Such PLC elements are known from the documents US 6 050 208, US 5 778 813, DE-A 198 25 083, DE-A 198 25 085, DE-A 198 25 084, DE-A 198 25 087 and DE-A 198 35 727. Usually these are Composite elements manufactured in such a way that the starting materials for Production of the polyisocyanate polyadducts in one cast or cast between the metal plates be injected. Since the reactive output components for Production of the plastics in the composite element already at Mixing will start to react and complete filling of the Space between the metal plates is a prerequisite for one the product is in good condition, the process of injection represents Starting components a crucial and critical step the manufacture of the composite elements.

The present invention was based on the object Improved method for producing the above Develop composite elements. This procedure should be straight filling the space between plates (i) and (iii) in particular with reactive starting components for the production of Plastics (ii) between the plates (i) and (iii) optimized become. This manufacturing process should in particular Significantly reduce the proportion of defective elements and a safe one Introducing liquid components between the plates of the Allow composite element. In particular, you should Cavities between layers (i) and (iii) are avoided, d. H. the space to be filled between (i) and (iii) should be as possible complete with the starting components for the preparation of (ii) be filled.

This object was achieved in that the Starting materials for the production of (ii) in liquid state in fills the space between (i) and (iii) and during it Filling process a negative pressure in the space to be filled between (i) and (iii) generated. This has the advantage that the liquid in the room is "sucked" and also small cavities with the Liquid to be filled. The negative pressure is preferably in the space to be filled 0.2 bar to 0.8 bar, d. H. the pressure in the form to be filled is 0.8 to 0.2 bar lower than Ambient air pressure. The negative pressure caused, for example, by generally known vacuum pumps can be generated is preferred achieved in that (i) and / or (iii) in addition to the or the openings (iv) in (i) and / or (iii) through which the Starting materials for the production of (ii) are entered via have at least one other opening (v) through which the vacuum is created. Is preferred between a vacuum pump, the Creates negative pressure, and the opening (v) in (i) a hose interposed. This hose can, for example, on (i) be pressed or glued. The amounts of starting materials for Manufacture of (ii) are difficult to size so that the space to be filled (R) is being filled, but an overflow is prevented. Therefore, a larger amount is preferred Starting components for the production of (ii) in the space between (i) and (iii) given that this can accommodate. The resulting overflow is preferably discharged through openings (v). Once the space between (i) and (iii) with the starting components for the production of (ii) is completely filled an increase in the liquid in the tube, which is preferred is transparent, the filling is finished and the openings (iv) and (v) be closed. Closing the openings can preferred with a plastic or metal plug, for example with a screw cap that is either in the overflow vessel or preferably between the overflow vessel and (i) and / or (iii) located. The openings (iv) preferably remain until End of curing of the mixture (a) and (b) by the fixed mixing head closed. The one to be filled preferably has Space between (i) and (iii) only openings (iv) and (v) , with the outflow end, preferably mixing head, at (iv) and the vacuum is applied to (v). Because after this preferred embodiment, no air in the space to be filled can reach, it is possible to generate a negative pressure.

Layers (i) and (iii) usually have no features on that to attach an outflow end for filling serve the space between (i) and (iii) with liquids can. The expression "outflow" can be common Trade facilities with the help of which liquids are filled are, for example, tank sockets, hose ends, mixing heads Static mixer or the like. It is preferably the Outflow around a mixing head. Such mixing heads are general known and for example in connection with usual Metering devices for polyurethane systems commercially available. The Attachment of the outflow end, preferably the mixing head, can preferably take place such that the outflow end of the Conveyor or a holder for the outflow end of the Conveyor device at at least three locations, preferably three to six Places, particularly preferably four or five places with the layer (i) is screwed. The liquid is preferably passed through at least one opening (iv) in (i) and / or (iii) in the room between (i) and (iii). One can prefer to attach for example a mixing head bolt with a thread that for attaching the mixing head or a bracket for the Serve mixing head, shoots into the layer (i). These bolts can preferably tapered on the side facing away from the thread in order to to be able to introduce them more easily into layer (i). Bolts preferably have a diameter of 6 mm to 20 mm and one Length from 8 mm to 42 mm. The thread after the fixation the bolt is directed outwards, d. H. on the side of (i), that facing away from (iii) preferably has a length of 4 mm up to 30 mm. The bolts are inserted, for example, by Shoot with the help of a bolt feed tool that is commercial z. B. is available from Hilti. Preferably, (i) thus thread on, with the help of which the outflow end at the opening (iv) through which the liquid is filled with (i) is screwed. One can prefer to improve the seal between the outflow end and the layer (i) between the layer (i) and the mixing head an O-ring made of an elastic material fix. Such O-rings are generally known and can be found in their dimensions to the diameter of the opening (iv) and the Mixing head can be matched. The mixing head is preferably fixed thus close to the opening (iv) in (i) or (iii) through which the Entry of the starting materials takes place.

It is particularly preferred not to attach the outflow end directly with the layer (i), but fixes the outflow end to one Bracket that is screwed to (i). With this bracket, made of common materials such as plastics, wood or can preferably consist of conventional metals preferably around a construction with holes which led the thread fixed on (i) and for example be fastened with appropriate nuts. In addition, the Bracket fasteners for the outflow end, for example plug connections, screw connections or edges, with which the outflow end through elastic bands with the Bracket can be clamped. This is particularly preferred Outflow end attached to the bracket at at least three points to avoid tilting. One is therefore preferred Hold on at least three threads that are attached to (i), screw and fix the mixing head on this holder. The Bolts can be made after completion of the composite elements sawn off, for example, on the surface of (i).

Filling the space between (i) and (iii) can be done with usual Conveyors, preferably continuously, carried out with, for example, high and low pressure machines, preferably high pressure machines. Filling is preferably carried out with a high pressure machine via one or more, preferably one Mixing head, in which the starting components are mixed, in a single step, preferably injection process. In a single injection process means that the filling of the Space between (i) and (iii) for example with the Starting materials for the production of (ii) before full filling is not interrupted. The raw materials are thus preferably in a single shot under pressure in the space between (i) and (iii) given. This is especially true if it is the liquid is a reactive mixture with the reaction hardens. It is therefore preferred to wear the Starting materials by means of a high pressure apparatus over one or more, preferably a mixing head. Filling the space between (i) and (iii) can be both in the vertical orientation of (i) and (iii), as well as in the horizontal alignment of (i) and (iii) respectively.

Layers (i) and (iii) can preferably be used as conventional ones Plastic, wood or preferably metal plates, for example Iron, steel, copper and / or aluminum plates, with the thicknesses according to the invention are used.

Both (i) and (ii) can be coated, for example primed, primed, painted and / or with common plastics coated in the manufacture of the invention Composite elements are used. (I) and (iii) are preferred uncoated and particularly preferably, for example, by conventional means Sandblasting used cleaned.

The width of the composite elements can usually be 0.5 m to 10 m, preferably be 1 m to 5 m. The length of the composite elements can generally 0.5 m to 10 m, preferably 1 m to 5 m be. Layers (i) and (iii) are preferably parallel arranged. The lateral edges of the space between (i) and (iii), the filled with (ii) are preferably sealed, preferred with plastic, paper or metal foils or plates, particularly preferably metal plates, for example glued, welded or pressed, preferably welded, and the can optionally also serve as a spacer.

The space to be filled can preferably be dried. This offers the advantage that in particular liquid components to be filled, which are reactive towards water, for example isocyanates, do not react in an undesirable side reaction. Drying, which preferably takes place immediately before filling for example using hot air or compressed air. Furthermore, the space to be filled between (i) and (iii) by heating (i) and / or (iii) to one Temperature from 20 ° C to 150 ° C for a period of 10 minutes to 180 minutes dry. Preferably, the space to be filled between (i) and (iii) dry by a fan that blows air through openings (iv) and (v) in (i) and / or (iii) through the space to be filled between (i) and (iii).

The openings (iv) and (v) are preferably Bores in (i) and / or (iii) with a diameter of 0.5 cm to 5.0 cm in (i) and / or (iii).

The space between (i) and (iii) with the starting materials Manufacturing of (ii) does not have to fill the entire room between (i) and (iii). Both (i) and (iii) can protrude at the edges beyond (ii), d. H. only in one Part of (i) and (iii) binds (i) via (ii) to (Iii). For example, the space between (i) and (iii) before the filling with the raw materials are sealed in such a way that the seal is within the range of (i) and (iii) enclosed space and edges of (i) and / or (iii) protrude.

The conveying capacity can be dependent on what has to be filled Volume can be varied. To ensure a homogeneous curing of (ii) ensure the funding capacity and funding facility preferably chosen such that the space to be filled within 0.5 to 20 min with the components for the preparation of (ii) can be filled. It is preferably low pressure or particularly preferably high pressure machines, preferably with Piston metering, particularly preferably axial piston metering, with preference the storage container with agitator and preferably temperature controlled is designed and preferably a circuit Storage container mixing head storage container is present, preferably the Discharge capacity is 0.1 to 3.0 kg / sec.

In the development of suitable manufacturing processes found that an uncontrolled leakage of liquid Starting components for the manufacture of (ii) hardly become defects fix it. Due to the limited amount per shot introduces uncontrolled loss of raw material for the production of (ii) incomplete filling of the space between (i) and (iii). Because of the quick response and the very good Liability of (ii) to (i) and (iii) arise from a incomplete filling of large areas in the composite element that no (ii) included and also no longer with starting components can be filled. Such composite elements must unfortunately be discarded.

To prevent loss of output components, it has therefore proved to be advantageous, the shape to be filled very precisely check for leaks. Usually the Layers (i) and (iii) in a suitable arrangement, for example parallel to each other, fixed. The distance is usually like this chosen so that the space (R) between (i) and (iii) has a thickness of 10 to 300 mm. The fixation of (i) and (iii) can for example by spacers z. B. in a form or suitable bracket. The edges of the space will be usually sealed such that the space between (i) and (iii) with the liquid or the starting components Production of (ii) can be filled completely Outflow of these starting components before the complete Filling is prevented. Sealing can be done with usual Plastic, paper or metal foils and / or plates, the for example glued, welded or pressed and the can optionally also serve as spacers. This preferred sealing does not apply to that preferred openings (iv) and (v), which were shown at the beginning.

Checking the tightness of (R) before filling with the Starting components are preferably made by Differential pressure measurement. The expression pressure difference measurement is to be understood as that one tries to find a pressure difference between the room (R) and build up the outside environment over a period of time, for example, by trying to find a sub or To achieve overpressure in relation to the external environment. This can by conventional vacuum pumps or generally known compressors, that pump air or gas into the room (R). can a stable overpressure or underpressure are generated in (R), so this indicates an adequately dense cavity that matches the Starting components for the production of (ii) can be filled. It should be noted that the openings (iv) or (v), which is used to fill (R) with the starting components or as ventilation openings or as overflow openings for Leakage of excess starting components also provides temporarily seals. If necessary, at least one of these openings serve to turn the vacuum pump or compressor on (R) to connect.

The form to be filled preferably consists of the specified ones Layers (i) and (iii), which are preferably arranged in parallel, and preferably from seals between layers (i) and (iii) which will leak the liquid when filling prevent. Layer (ii) is thus preferably adherent between layers (i) and (iii) are arranged.

The liquid for the preparation of (ii) (a) preferably contains Isocyanates and (b) compounds reactive towards isocyanates. Layer (ii) is therefore preferred Polyisocyanate polyadducts. In this document are among the terms "Starting materials" or "Starting components" in particular (a) Isocyanates and (b) compounds reactive towards isocyanates understand, but if applicable, insofar as they are used, also (c) gases, (d) catalysts, (e) auxiliaries and / or (f) Propellant.

The reaction of (a) with (b) to (ii) in is preferably carried out Presence of 1 to 50% by volume of gases (c). Preferably sets one as (b) polymer polyols. The implementation is preferably carried out of (a) with (b) in the presence of (f) blowing agents.

The starting components for the production of the Polyisocyanate polyadducts are usually made at a temperature of 0 to 100 ° C, preferably from 20 to 60 ° C, mixed and as already described in the space between (i) and (iii). The Mixing can be done mechanically using a stirrer or a Stirring screw, but preferred by the high pressure machines Common countercurrent principle, in which A and B component Jet meet in the mixing head under high pressure and mix, the beam of each component also being divided can be. The reaction temperature, i.e. H. the temperature at which Implementation takes place depending on the material thickness usually> 20 ° C, preferably 50 to 150 ° C.

The polyisocyanate polyadducts (ii) according to the invention Composite elements produced preferably have Elastic modulus of> 275 MPa in the temperature range from -45 to + 50 ° C (after DIN 53457), an adhesion to (i) and (iii) of> 4 MPa (according to DIN 53530), an elongation of> 30% in the temperature range from -45 to + 50 ° C (according to DIN 53504), a tensile strength of> 20 MPa (according to DIN 53504) and a compressive strength of> 20 MPa (according to DIN 53421).

The composite elements according to the invention can be produced carry out in such a way that between (i) and (iii) polyisocyanate Polyaddition products (ii), usually polyurethanes, the optionally have urea and / or isocyanurate structures can, by reacting (a) isocyanates with (b) Isocyanate-reactive compounds, if appropriate in the presence of blowing agents (f), 1 to 50% by volume, based on the volume the polyisocyanate polyadducts, at least one gas (c), (d) produces catalysts and / or (e) auxiliaries, where preferably (ii) adheres to (i) and (iii). The production Such polyisocyanate polyadducts (ii) are common have been described.

The surfaces of (i) and (iii) can be prepared before the Composite elements for cleaning and increasing the Surface roughness with sand or steel balls, preferably with corundum or Iron grit to be blasted. This blasting can be done according to the usual Processes are carried out in which the blasting material is, for example, high pressure hits the surfaces. Suitable equipment for such treatment are commercially available.

By treating the surfaces of (i) and (iii), the are in contact with (ii) after the implementation of (a) with (b), leads to a significantly improved liability of (ii) to (i) and (Iii). The blasting is preferred directly before the introduction of the Components for the production of (ii) in the space between (i) and (iii) performed. The surfaces of (i) and (iii) to which (ii) should adhere, are preferably free of inorganic and / or organic substances that reduce adhesion, for example Dust, dirt, oils and greases or generally as Mold release agents known substances.

The starting materials (a), (b), (c), (d), (e) and (f) in the process according to the invention are described below by way of example:
Suitable isocyanates (a) are the aliphatic, cycloaliphatic, araliphatic and / or aromatic isocyanates known per se, preferably diisocyanates, which may have been biuretized and / or iscyanurated by generally known methods. Examples include: alkylene diisocyanates with 4 to 12 carbon atoms in the alkylene radical, such as 1,12-dodecane diisocyanate, 2-ethyl-tetramethylene diisocyanate-1,4, 2-methylpentamethylene diisocyanate-1,5, tetramethylene diisocyanate-1,4, lysine ester diisocyanates (LDI) , 1,6-hexamethylene diisocyanate (HDI), 1,3-cyclohexane and / or 1,4-diisocyanate, 2,4- and 2,6-hexahydrotolylene diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,2 ' - and 2,4'-dicyclohexylmethane diisocyanate and the corresponding isomer mixtures, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,4- and / or 2,6-tolylene diisocyanate (TDI), 4, 4'-, 2,4'- and / or 2,2'-diphenylmethane diisocyanate (MDI), polyphenylpolymethylene polyisocyanates and / or mixtures containing at least two of the isocyanates mentioned. In addition, di- and / or polyisocyanates containing ester, urea, allophanate, carbodiimide, uretdione and / or urethane groups can be used in the process according to the invention. 2,4'-, 2,2'- and / or 4,4'-MDI and / or polyphenylpolymethylene polyisocyanates are preferably used, particularly preferably mixtures containing polyphenylpolymethylene polyisocyanates and at least one of the MDI isomers.

As (b) isocyanate-reactive compounds For example, connections are used that are considered opposite Isocyanate reactive groups hydroxyl, thiol and / or primary and / or have secondary amino groups and usually a Have molar weight from 60 to 10,000 g / mol, e.g. B. Polyols selected from the group of polymer polyols, Polyether polyalcohols, polyester polyalcohols, polythioether polyols, hydroxyl-containing polyacetals and hydroxyl-containing aliphatic Polycarbonates or mixtures of at least two of the above Polyols. These compounds usually have one Functionality towards isocyanates from 2 to 6 and a molecular weight from 400 to 8000 and are generally known to the person skilled in the art.

For example, the following come as polyether polyalcohols known technology through the addition of alkylene oxides, for example tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, styrene oxide and preferably ethylene oxide and / or 1,2-propylene oxide are available on common starter substances. As Starter substances can be, for example, known aliphatic, araliphatic, cycloaliphatic and / or aromatic compounds are used, the at least one, preferably 2 to 4 Hydroxyl groups and / or at least one, preferably 2 to 4 Contain amino groups. For example, as starter substances Ethanediol, diethylene glycol, 1,2- or 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, glycerin, Trimethylolpropane, neopentyl glycol, sugar, for example sucrose, Pentaerythritol, sorbitol, ethylenediamine, propanediamine, Neopentanediamine, hexamethylenediamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 2- (ethylamino) ethylamine, 3- (methylamino) propylamine, Diethylenetrimamine, dipropylenetriamine and / or N, N'-bis (3-aminopropyl) ethylenediamine can be used.

The alkylene oxides can be individually, alternately in succession or can be used as mixtures. Alkylene oxides are preferred used which lead to primary hydroxyl groups in the polyol. Particularly preferred polyols are those which are used for Completion of the alkoxylation were alkoxylated with ethylene oxide and thus have primary hydroxyl groups.

As polymer polyols, a special class of polyether polyols, can be compounds generally known from polyurethane chemistry are used, preferably styrene-acrylonitrile graft polyols.

Especially the use of polymer polyols can shrink the Polyisocyanate polyaddition product, for example the Significantly reduce polyurethane and thus improve adhesion from (ii) to (i) and (iii). If necessary, as other measures to reduce shrinkage are preferred Blowing agents (f) and / or gases (c) are used.

Suitable polyester polyols can, for example, from organic Dicarboxylic acids having 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids with 4 to 6 carbon atoms, and polyhydric alcohols, preferably diols, with 2 to 12 Carbon atoms, preferably 2 to 6 carbon atoms become. The polyester polyols preferably have one Functionality from 2 to 4, especially 2 to 3, and a Molecular weight of 480 to 3000, preferably 600 to 2000 and especially 600 to 1500.

The composite elements according to the invention are preferred under Use of polyether polyalcohols as component (b) for Reaction with the isocyanates prepared, expediently such with an average functionality compared to isocyanates of 1.5 to 8, preferably 2 to 6, and a molecular weight of 400 to 8000th

The use of polyether polyalcohols offers significant Advantages through improved stability of the Polyisocyanate polyaddition products against hydrolytic cleavage and due to the lower viscosity, in each case in comparison with Polyester polyalcohols. The improved stability against hydrolysis is particularly advantageous when used in shipbuilding. The lower viscosity of the polyether polyalcohols and Reaction mixture for the preparation of (ii) containing the Polyether polyalcohols enable faster and easier filling of the Space between (i) and (iii) with the reaction mixture Manufacture of composite elements. Because of the considerable dimensions especially of structural parts in shipbuilding low-viscosity liquids of considerable advantage.

As isocyanate-reactive compounds can further in addition to the compounds mentioned with a conventional one Molecular weight of 400 to 8000 optionally diols and / or Trioles with molecular weights from 60 to <400 as Chain extenders and / or crosslinking agents in the inventive Procedures are used. To modify the mechanical Properties, e.g. B. the hardness, but the addition of Chain extenders, crosslinking agents or, if appropriate mixtures of these also prove to be advantageous. The Chain extenders and / or crosslinking agents preferably have Molecular weight from 60 to 300. Be considered for example aliphatic, cycloaliphatic and / or araliphatic Diols with 2 to 14, preferably 4 to 10 carbon atoms, such as z. B. ethylene glycol, 1,3-propanediol, 1,10-decanediol, o-, m-, p-dihydroxycyclohexane, diethylene glycol, dipropylene glycol and preferably 1,4-butanediol, 1,6-hexanediol and Bis (2-hydroxyethyl) hydroquinone, triols, such as 1,2,4-, 1,3,5-trihydroxycyclohexane, Glycerin and trimethylolpropane, low molecular weight hydroxyl group-containing polyalkylene oxides based on ethylene and / or 1,2-propylene oxide and the aforementioned diols and / or triols as Starter molecules and / or diamines such. B. diethyltoluenediamine and / or 3,5-dimethylthio-2,4-toluenediamine.

If so for the preparation of the polyisocyanate polyadducts Chain extenders, crosslinking agents or mixtures of which are used, they are conveniently used in one Amount from 0 to 30% by weight, preferably from 1 to 30% by weight, compared to the weight of the total used Isocyanate-reactive compounds (b) are used.

In addition, as (b) aliphatic, araliphatic, cycloaliphatic and / or aromatic carboxylic acids to optimize the Hardening course used in the production of (ii). Examples of such carboxylic acids are formic acid, acetic acid, Succinic acid, oxalic acid, malonic acid, glutaric acid, adipic acid, Citric acid, benzoic acid, salicylic acid, phenylacetic acid, Phthalic acid, toluenesulfonic acid, derivatives of the acids mentioned, Isomers of the acids mentioned and any mixtures of the mentioned acids. The weight fraction of these acids can be 0 to 5 wt .-%, preferably 0.2 to 2 wt .-%, based on the Total weight of (b).

With the use of amine-started polyether polyalcohols also the hardening behavior of the reaction mixture Production of (ii) can be improved. The are preferred Compounds (b), as well as the other components for the production of (ii) used with the lowest possible water content, to the formation of carbon dioxide by reaction of the water with Avoid isocyanate groups.

In general, component (c) for the preparation of (ii) known compounds are used which have a boiling point a pressure of 1 bar less (i.e. at lower Temperatures as) -50 ° C, for example air, carbon dioxide, Nitrogen, helium and / or neon. Air is preferably used. Component (c) is preferred over component (a), particularly preferably inert towards components (a) and (b), d. H. reactivity of the gas towards (a) and (b) is hardly preferably not to be demonstrated. The use of gas (c) differs fundamentally from the use of conventional blowing agents for the production of foamed polyurethanes. While usual Blowing agents (f) are used in liquid form or in the case of gaseous physical blowing agent in the polyol component are soluble to a small extent) and during the Implementation either evaporate due to heat or but in the case of water due to the reaction with the Isocyanate groups develop gaseous carbon dioxide in the Component (c) is already preferred in the present invention gaseous as an aerosol, for example in the polyol component used.

Well-known compounds can be used as catalysts (d) are used, the reaction of isocyanates with the accelerate compounds reactive towards isocyanates, preferably a total catalyst content of 0.001 to 15 wt .-%, in particular 0.05 to 6 wt .-%, based on the Weight of the total isocyanate reactive Connections. For example, the following Compounds are used: triethylamine, tributylamine, Dimethylbenzylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, N, N, N ', N'-tetramethyl-diamino-diethyl ether Bis (dimethylaminopropyl) urea, N-methyl or N-ethylmorpholine, N-cyclohexylmorpholine, N, N, N ', N'-tetramethylethylenediamine, N, N, N ', N'-tetramethylbutanediamine, N, N, N', N'-tetramethylhexanediamine-1,6, Pentamethyldiethylenetriamine, dimethylpiperazine, N-dimethylaminoethylpiperidine, 1,2-dimethylimidazole, 1-azabicyclo- (2,2,0) -octane, 1,4-diazabicyclo- (2,2,2) octane (Dabco) and Alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyl and N-ethyl-diethanolamine, dimethylaminoethanol, 2- (N, N-dimethylaminoethoxy) ethanol, N, N ', N "-Tris- (dialkylaminoalkyl) hexahydrotriazines, e.g. N, N', N" -Tris- (dimethylaminopropyl) -s-hexahydrotriazine, Iron (II) chloride, zinc chloride, lead octoate and preferably Tin salts such as tin dioctoate, tin diethylhexoate, dibutyltin dilaurate and / or dibutyldilauryltin mercaptide, 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tetraalkylammonium hydroxides, such as Tetramethylammonium hydroxide, alkali hydroxides, such as sodium hydroxide, Alkaline alcoholates, such as sodium methylate and potassium isopropylate, and / or Alkali salts of long-chain fatty acids with 10 to 20 carbon atoms and optionally pendant OH groups.

It has proven to be very advantageous to manufacture (ii) in the presence of (d) to effect the reaction accelerate.

The reaction mixture for the preparation of the Polyisocyanate polyaddition products (ii) can optionally (e) assistants be incorporated. Examples include fillers, surface-active substances, dyes, pigments, flame retardants, Hydrolysis protection, fungistatic, bacteriostatic Substances and foam stabilizers.

As surface-active substances such. B. Connections in Consider which to support the homogenization of the Serve starting materials and are also suitable if necessary, the Regulate structure of plastics. Be mentioned for example emulsifiers, such as the sodium salts of castor oil sulfates or of fatty acids and salts of fatty acids with amines, e.g. B. oleic acid diethylamine, stearic acid diethanolamine, ricinoleic acid Diethanolamine, salts of sulfonic acids, e.g. B. alkali or Ammonium salts of dodecylbenzene or dinaphthylmethane disulfonic acid and Ricinoleic acid. The surface-active substances are usually in amounts of 0.01 to 5 wt .-%, based on 100 wt .-% of total isocyanate reactive Compounds (b) applied.

Suitable flame retardants are, for example Tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloropropyl) phosphate, Tris (1,3-dichloropropyl) phosphate, Tris (2,3-dibromopropyl) phosphate, tetrakis (2-chloroethyl) ethylene diphosphate, Dimethylmethanephosphonat, Diethanolaminomethylphosphonsäurediethylester as well commercially available halogen-containing flame retardant polyols. Except the halogen-substituted phosphates already mentioned can also inorganic or organic flame retardants, such as red phosphorus, Alumina hydrate, antimony trioxide, arsenic oxide, Ammonium polyphosphate and calcium sulfate, expandable graphite or cyanuric acid derivatives, such as B. melamine, or mixtures of at least two Flame retardants such as B. ammonium polyphosphates and melamine and optionally corn starch or ammonium polyphosphate, melamine and Expandable graphite and / or optionally aromatic polyester for Flame-proofing of the polyisocyanate polyaddition products used become. In general, it has proven useful to 5 to 50 wt .-%, preferably 5 to 25 wt .-% of the above Flame retardants, based on the weight of the total used compounds reactive towards isocyanates.

As fillers, in particular reinforcing fillers, are the known, conventional organic and inorganic fillers, reinforcing agents, weighting agents, agents to improve the abrasion behavior in paints, Understand coating agents, etc. In particular mentioned as examples: inorganic fillers such as silicate Minerals, e.g. layered silicates such as antigorite, serpentine, Hornblende, Amphibole, Chrisotil and Talc, metal oxides, like Kaolin, aluminum oxides, titanium oxides and iron oxides, metal salts, like chalk, heavy spar and inorganic pigments like Cadmium sulfide and zinc sulfide, as well as glass and. a .. Preferably used are made from kaolin (china clay), aluminum silicate and coprecipitates Barium sulfate and aluminum silicate as well as natural and synthetic fibrous minerals such as wollastonite, metal and Glass fibers of short length. Coming as organic fillers for example: coal, melamine, rosin, Cyclopentadienyl resins and graft polymers as well as cellulose fibers, polyamide, Based on polyacrylonitrile, polyurethane, polyester fibers of aromatic and / or aliphatic dicarboxylic acid esters and especially carbon fibers. The inorganic and organic Fillers can be used individually or as mixtures.

Preferably, 10 to 70% by weight is used in the preparation of (ii) Fillers, based on the weight of (ii), as (e) auxiliaries on. Talcum, kaolin, Calcium carbonate, heavy spar, glass fibers and / or micro glass balls. The size of the particles of the fillers should preferably be chosen so that that the registration of the components for the preparation of (ii) in the Space between (i) and (iii) is not obstructed. Especially the fillers preferably have particle sizes of <0.5 mm.

The fillers are preferably mixed with the Polyol component in the implementation to produce the Polyisocyanate polyaddition products used.

The fillers can be used in comparison For example, the thermal expansion coefficient of steel is greater To reduce polyisocyanate polyadducts and thus the of the steel. This for a sustainable, firm network between layers (i), (ii) and (iii) is particularly advantageous, because this reduces the stresses between the layers thermal stress occur.

Preferred for the production of (ii) are customary as (e) Foam stabilizers used that are commercially available and the Are generally known to those skilled in the art, for example in general known polysiloxane-polyoxyalkylene block copolymers, e.g. B. Tegostab 2219 from the Goldschmidt company. The share of this Foam stabilizers in the production of (ii) is preferably 0.001 to 10% by weight, particularly preferably 0.01 to 10% by weight, in particular 0.01 to 2 wt .-%, based on the weight of the preparation of (ii) components (b), (e) and optionally (D). The use of these foam stabilizers causes the Component (c) in the reaction mixture for the preparation of (ii) is stabilized.

In general, polyurethane chemistry can be used as blowing agent (f) known blowing agents are used, for example physical and / or chemical blowing agents. Such physical Blowing agents generally have a boiling point at one Pressure of 1 bar greater (i.e. at temperatures higher than) -50 ° C. Examples of physical blowing agents are e.g. B. CFC, HCFC, HFC, aliphatic hydrocarbons, cycloaliphatic Hydrocarbons, each with 4 to 6, for example Carbon atoms or mixtures of these substances, for example Trichlorofluoromethane (boiling point 24 ° C), chlorodifluoromethane (boiling point -40.8 ° C), dichlorofluoroethane (boiling point 32 ° C), chlorodifluoroethane (Boiling point -9.2 ° C), dichlorotrifluoroethane (boiling point 27.1 ° C), Terafluoroethane (boiling point -26.5 ° C), hexafluorobutane (boiling point 24.6 ° C), iso-pentane (boiling point 28 ° C), n-pentane (boiling point 36 ° C), Cyclopentane (boiling point 49 ° C).

As a chemical blowing agent, i. H. Propellant due to a Reaction, for example with isocyanate groups, gaseous Products form, for example, come water, hydrate water-containing Compounds, carboxylic acids, tertiary alcohols, e.g. B. t-butanol, Carbamates, for example those in EP-A 1000955, especially on pages 2, lines 5 to 31 and page 3, lines 21 to 42 described carbamates, carbonates, e.g. B. ammonium carbonate and / or ammonium hydrogen carbonate and / or guanidine carbamate in Consideration.

Preferred blowing agents (f) are water and / or carbamates used.

The blowing agents (f) are preferably used in an amount sufficient to obtain the preferred density of (ii) from 350 to 1200 kg / m ³ . This can be determined using simple routine experiments which are generally known to the person skilled in the art. The blowing agents (f) are particularly preferably used in an amount of 0.05 to 10% by weight, in particular 0.1 to 5% by weight, in each case based on the total weight of the polyisocyanate polyadducts.

The weight of (ii) by definition corresponds to the weight of the for the production of (ii) components (a), (b) and optionally (c), (d), (e) and / or (f).

For the production of the invention The polyisocyanate polyaddition products are the isocyanates and the isocyanates implemented reactive compounds in such amounts, that the equivalence ratio of NCO groups of the isocyanates (a) to the sum of the reactive hydrogen atoms opposite Isocyanate-reactive compounds (b) and optionally (f) 0.85 to 1.25: 1, preferably 0.95 to 1.15: 1 and in particular 1 to 1.05: 1. If (ii) at least partially Isocyanurate groups bound, usually a ratio of NCO groups to the sum of the reactive hydrogen atoms from 1.5 to 60: 1, preferably 1.5 to 8: 1, applied.

The polyisocyanate polyadducts are usually made after the one shot process or the prepolymer process, for example with the help of high pressure or low pressure technology manufactured.

It has proven to be particularly advantageous after the Two-component process to work and the isocyanates reactive compounds (b), optionally the blowing agents (f) and optionally the catalysts (d) and / or auxiliaries (e) in to combine component (A) (polyol component) and preferred to mix intimately with one another and as component (B) To use isocyanates (a).

Component (c) can contain the reaction mixture containing (a), (b) and optionally (f), (d) and / or (e) are fed in, and / or the individual components (a), (b) already described, (A) and / or (B). The component that is mixed with (c) is usually liquid. The components are preferred mixed into component (b).

The mixing of the corresponding component with (c) can be done after generally known methods. For example, (c) by well-known loading devices, for example Air loading devices, preferably under pressure, for example compressed from a pressure vessel or by a compressor, z. B. supplied through a nozzle of the corresponding component become. There is preferably extensive mixing of the corresponding components with (c), so that gas bubbles from (c) in the usually liquid component preferably a size of 0.0001 to 10, particularly preferably 0.0001 to 1 mm.

The content of (c) in the reaction mixture for the production of (ii) can be in the return line of the high pressure machine well-known measuring devices on the density of the reaction mixture be determined. The content of (c) in the reaction mixture can preferred based on a control unit automatically this density can be regulated. The component density can during the usual circulation of the material in the machine too determined online at very low circulation speed and be regulated.

Find the composite elements available according to the invention Mainly used in areas where construction elements needed to withstand large forces, for example as Construction parts in shipbuilding, e.g. B. in ship hulls, for example ship's double hulls with one outer and one inner wall, and cargo space covers, cargo space partitions, Loading flaps or in structures, such as bridges or as Construction elements in house construction, especially in high-rise buildings.

The composite elements according to the invention are not classic To be confused with sandwich elements that have a polyurethane core and / or contain rigid polyisocyanurate foam and are usually used for thermal insulation. such known sandwich elements would be comparative due to their lower mechanical strength not for the above Suitable areas of application.

Claims (10)

1. Process for producing composite elements which have the following layer structure: a) 2 to 20 mm metal, plastic or wood b) 10 to 300 mm plastic, c) 2 to 20 mm metal, plastic or wood characterized in that the starting materials for the production of (ii) in liquid state are filled into the space between (i) and (iii) and during this filling process a negative pressure is created in the space to be filled between (i) and (iii). 2. The method according to claim 1, characterized in that the negative pressure in the space to be filled is 0.2 to 0.8 bar is. 3. The method according to claim 1, characterized in that (i) and / or (iii) in addition to the opening (s) (iv) in (i) and / or (iii), via which the starting materials for Manufacture of (ii) registered over at least have another opening (v) through which the vacuum is created. 4. The method according to claim 1, characterized in that one the raw materials continuously without interruption in one single work step in the space to be filled between (i) and (iii). 5. The method according to claim 1, characterized in that the starting materials by means of a high pressure apparatus enters one or more mixing heads. 6. The method according to claim 5, characterized in that one the mixing head at the opening (iv) in (i) or (iii) the entry of the raw materials takes place, tightly fixed. 7. The method according to claim 5, characterized in that the mixing head or a holder for the mixing head screwed to the layer (i) at least three places. 8. The method according to claim 1, characterized in that (ii) Polyisocyanate polyaddition products are available by reacting the starting materials (a) isocyanate and (b) compounds reactive towards isocyanates. 9. Composite elements obtainable by a method according to one of claims 1 to 8. 10. Ships or structures containing composite elements after Claim 9.