WO2003002341A1

WO2003002341A1 - Method for introducing fluids into a mould by means of a delivery device

Info

Publication number: WO2003002341A1
Application number: PCT/EP2002/006691
Authority: WO
Inventors: Gerhard Bernard
Original assignee: Basf Aktiengesellschaft
Priority date: 2001-06-27
Filing date: 2002-06-18
Publication date: 2003-01-09
Also published as: EP1414643A1; DE10130650A1

Abstract

The invention relates to a method for introducing fluids into a mould by means of a delivery device which comprises an upper layer (i) and a lower layer (iii), said upper layer (i) comprising at least one opening (iv) through which the liquid passes. The invention is characterized in that the discharge end of the delivery device or a mounting for the discharge end of the delivery device is screwed onto the layer (i) in at least three places.

Description

Method for introducing liquids into a mold by means of a conveyor

description

The invention relates to methods for introducing liquids by means of a conveyor into a mold which has an upper layer (i) with at least one opening (iv) through which the liquid is filled and a lower layer (iii).

For the construction of ships, for example hulls and cargo space covers, bridges, roofs or high-rise buildings, construction parts must be used that can withstand considerable loads from external forces. Due to these requirements, such construction parts usually consist of metal plates or metal supports, which are reinforced by a corresponding geometry or suitable struts. Due to increased safety standards, the hulls of tankers usually consist of an inner and an outer hull, with each hull being constructed from 15 mm thick steel plates which are connected to one another by approximately 2 m long steel struts. Since these steel plates are exposed to considerable forces, both the outer and the inner steel shell are stiffened by welded-on reinforcement elements. A disadvantage of these classic construction parts are both the considerable amounts of steel that are required and the time-consuming and labor-intensive production. In addition, such structural parts have a considerable weight, which results in a lower tonnage of the ships and an increased fuel requirement. In addition, such classic construction elements based on steel are very maintenance-intensive, since both the outer surface and the surfaces of the steel parts between the outer and inner shell have to be regularly protected against corrosion.

As a replacement for the steel structures, SPS elements (sandwich plate system) are known which contain a composite of metal and plastic. The adhesion of the plastic to the two metal layers creates 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. These composite elements are usually produced in such a way that the starting materials for production the polyisocyanate polyadducts are poured or sprayed between the metal plates in a single step. Since the reactive starting components for the production of the plastics in the composite element already start to react when they are mixed and a complete filling of the space between the metal plates is a prerequisite for a perfect product, the process of injecting the starting components is a crucial and critical step in the production of the composite elements In the case of reactive liquids that harden, leakages mean additional work.

The object of the present invention was therefore to develop an improved method for introducing liquids into a mold by means of a conveying device, in which the space between the plates (i) and (iii) in particular is filled, in particular with the starting components for the production of plastics (ii) between plates (i) and (iii) is optimized. This manufacturing process should, in particular, significantly reduce the proportion of defective elements and enable liquid components to be safely introduced between the plates of the composite element.

This object was achieved according to the invention by screwing the outflow end of the conveying device or a holder for the outflow end of the conveying device to the layer (i) at at least three locations, preferably three to six locations, particularly preferably four or five locations. The liquid is preferably filled through at least one opening (iv) in (i) and / or (iii) into the space between (i) and (iii).

The expression "outflow end" can be conventional devices by means of which liquids are filled, for example tank sockets, hose ends, mixing heads, static mixers or the like. The outflow end is preferably a mixing head. Mixing heads of this type are generally known and are commercially available, for example, in connection with conventional metering devices for polyurethane systems.

The "liquids" are preferably liquid starting components for the production of plastics, preferably those which adhere to (i) and (iii), particularly preferably the starting components for the production of polyisocyanate polyadditions described later - products. Layers (i) and (iii) usually have no features that can be used to attach an outflow end for filling with liquids. The attachment can preferably be carried out by shooting bolts with a thread into the layer (i), which are used to attach the outflow end or the holder. These bolts can preferably taper to a point on the side facing away from the thread in order to be able to introduce them more easily into the layer (i). The bolts preferably have a diameter of 6 mm to 20 mm and a length of 8 mm to

10 42 mm. The thread that faces outward after the bolts are fixed, i.e. on the side of (i) facing away from (iii) preferably has a length of 4 mm to 30 mm. The bolts are inserted, for example, by shooting with the aid of a bolt pushing tool which is commercially available e.g. in the

15 Hilti is available. Preferably, (i) thus has threads by means of which the outflow end is screwed to (i) at the opening (iv) through which the liquid is filled. It is preferable to improve the seal between the outflow end and the layer (i) between the layer (i) and the

20 Mixing head fix an O-ring made of an elastic material. Such O-rings are generally known and their dimensions can be matched to the diameter of the opening (iv) and the mixing head.

25 Particularly preferably, the outflow end is not attached directly to the layer (i), but the outflow end is fixed to a holder which is screwed to (i). This holder, which can consist of conventional materials, for example plastics, wood or preferably conventional metals, is concerned

30 is preferably a construction which has bores through which the threads fixed on (i) are guided and fastened, for example, by means of corresponding nuts. In addition, the holder has fastening elements for the outflow end, for example plug connections, screw connections or

35 edges with which the outflow end can be braced with elastic brackets. The outflow end is particularly preferably fastened to the holder at at least three points in order to avoid tilting.

40 One is therefore preferred to mount at least three

Screw threads that are attached to (i) and fix the mixing head to this holder. After completion of the composite elements, the bolts can be sawed off, for example, on the surface of (i).

45 The filling of the space between (i) and (iii) can be carried out with conventional conveying devices, preferably continuously, for example with high and low pressure machines, preferably high pressure machines. Filling with a high-pressure machine is preferably carried out via one or more, preferably a mixing head, in which the starting components are mixed, in a single working step, preferably an 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), is not interrupted before the filling is complete. The starting materials are thus preferably given in a single shot under pressure in the space between (i) and (iii). This is especially true if the liquid is a reactive mixture that hardens with the reaction. The starting materials are therefore preferably introduced by means of a high-pressure apparatus through one or more, preferably a mixing head. The space between (i) and (iii) can be filled both in the vertical orientation of (i) and (iii) and in the horizontal orientation of (i) and (iii).

The layers (i) and (iii) can preferably be used as conventional plastic, wood or preferably metal plates, for example iron, steel, copper and / or aluminum plates, with the thicknesses according to the invention.

Both (i) and (ii) can be coated, for example primed, primed, painted and / or coated with conventional plastics, in the production of the composite elements according to the invention. (I) and (iii) are preferably used uncoated and particularly preferably cleaned, for example, by conventional iron shot blasting.

(I) and / or (iii) preferably have at least one further opening (v) in addition to the opening (s) through which the starting components for the production of (ii) are introduced. The amounts of starting materials for the production of (ii) are difficult to measure in such a way that the space (R) to be filled is filled, but overflow is prevented. Therefore, a larger amount of starting components for the production of (ii) in the space between (i) and (iii) is preferably added than it can accommodate. The resulting overflow is preferably discharged through openings (v). Overflow vessels can preferably be attached to the opening (s). These overflow vessels are preferably in a position above the space to be filled between (i) and (iii) with the starting materials for the production of (ii). This has the advantage that only after complete filling with the starting materials, an increase in the still liquid, ie not yet fully reacted starting materials can be found in the overflow vessels. The complete filling of the space between (i) and (iii) can thus be determined from the increase in the starting components in the overflow vessels. The openings can be closed, for example, with a plastic or metal plug, preferably with a screw cap, which is located either in the overflow vessel or preferably between the overflow vessel and (i) and / or (iii). The openings (iv) preferably remain closed by the fixed mixing head until the end of the curing process of the mixture (a) and (b).

In addition, one or preferably a plurality of openings (v) serve to allow air to escape from (R) during the filling process.

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

The space that is filled between (i) and (iii) with the starting materials for the production of (ii) need not represent the entire space between (i) and (iii). Both (i) and (iii) may protrude beyond the edges of (ii), i.e. only in a partial area of (i) and (iii) is there a binding of (i) via (ii) to (iii). For example, the space between (i) and (iii) can be sealed prior to filling with the starting materials such that the seal is located within the space enclosed by (i) and (iii) and edges of (i) and / or (iii ) survive.

The delivery rate can be varied depending on the volume to be filled. In order to ensure a homogeneous hardening of (ii), the conveying capacity and conveying device is preferably selected such that the space to be filled can be filled with the components for the production of (ii) within 0.5 to 20 minutes. It is preferably low-pressure or particularly preferably high-pressure machines, preferably with piston metering, particularly preferably axial piston metering, the storage tank preferably being designed with an agitator and preferably being temperature-controllable, and preferably a circuit of storage tank mixing head storage tank being present, the discharge rate preferably being Is 1 to 3.0 kg / sec.

The starting components for the preparation of the polyisocyanate polyadducts are usually mixed at a temperature of from 0 to 100 ° C., preferably from 20 to 60 ° C., and the like already introduced into the space between (i) and (iii). Mixing can be carried out mechanically by means of a stirrer or a stirring screw, but preferably by the countercurrent principle customary in high-pressure machines, in which the A- and B- 5-component jets meet and mix in the mixing head under high pressure, the jet of each component also can be divided. The reaction temperature, ie the temperature at which the reaction takes place, is usually> 20 ° C., preferably 10 50 to 150 ° C., depending on the material thickness.

During the development of suitable manufacturing processes, it was found that an uncontrolled leakage of liquid starting components for the production of (ii) hardly caused any errors

15 is correct. Due to the limited amount per shot, an uncontrolled loss of starting material for the production of (ii) leads to an incomplete filling of the space between (i) and (iii). Due to the quick reaction and the very good adhesion of (ii) to (i) and (iii), an incomplete

20 constant filling of large areas in the composite element, which contain no (ii) and can no longer be filled with starting components. Such composite elements unfortunately have to be discarded.

25 In order to prevent loss of starting components, it has therefore proven to be advantageous to check the shape to be filled very carefully for its tightness. Layers (i) and (iii) are usually fixed in a suitable arrangement, for example parallel to one another. The distance is usually

30 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 e.g. done in a form or suitable holder. The edges of the space are usually sealed such that the space between

35 (i) and (iii) can be completely filled with the liquid or the starting components for the production of (ii), but the outflow of these starting components before full filling is prevented. Sealing can be carried out using conventional plastic, paper or metal foils and / or

40 plates, which are glued, welded or pressed on, for example, and which can optionally also serve as spacers. This preferred sealing does not relate to the preferred openings (iv) and (v) which were presented at the beginning.

45 The tightness of (R) before filling with the starting components is preferably checked by measuring the pressure difference. The term pressure difference measurement is understood to mean that one tries to build up a pressure difference between the space (R) and the external environment over a certain period of time, for example by trying to achieve a negative or positive pressure in (R) in relation to the external environment. This can be achieved by conventional vacuum pumps or well-known compressors that pump air or gas into the room (R). If a stable overpressure or underpressure can be generated in (R), this indicates a sufficiently dense cavity that can be filled with the starting components for the production of (ii). It should preferably be noted that the openings (iv) and (v), which are used to fill (R) with the starting components or as ventilation openings or as overflow openings for the exit of excess starting components, are also temporarily sealed. If necessary, at least one of these openings can be used to connect the vacuum pump or compressor to (R).

During the filling of the liquid into the space between (i) and (iii), a negative pressure can preferably be generated in the space to be filled. This offers the advantage that the liquid is "sucked" into the room and that even small cavities are filled with the liquid. It is therefore preferred that the starting materials for the production of (ii) in the 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) , The vacuum in the space to be filled is preferably 0.2 to 0.8 bar, i.e. the pressure in the mold to be filled is 0.8 bar to 0.2 bar lower than the ambient air pressure. The negative pressure which can be generated, for example, by generally known vacuum pumps is preferably achieved in that (i) and / or (iii) in addition to the or the openings (iv) in (i) and / or (iii), via the the starting materials for the production of (ii) are entered, have at least one further opening (v) through which the negative pressure is applied.

The space to be filled can preferably be dried between (i) and (iii), in particular before filling. This has 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, can be carried out, for example, using hot air or compressed air. Furthermore you can fill the space between (i) and (iii) dry heating (i) and / or (iii) to a temperature of 20 to 150 ° C. for a period of 10 to 180 min. The space to be filled between (i) and (iii) can preferably be dried by a blower, the air through openings (iv) and (v) in (i) and / or (iii) through the space to be filled between (i) and (iii) conducts.

Composite elements which have the following layer structure are preferably produced using the method according to the invention:

(i) 2 mm to 20 mm, preferably 2 mm to 10 mm, particularly preferably 5 mm to 10 mm metal, plastic or wood, preferably metal, (ii) 10 mm to 300 mm, preferably 10 mm to 100 mm of a plastic, which results from the hardening of the liquid filled in the mold, (iii) 2 mm to 20 mm, preferably 2 mm to 10 mm, particularly preferably 5 mm to 10 mm metal, plastic or wood, preferably metal,

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

Accordingly, the form to be filled preferably consists of the specified layers (i) and (iii), which are preferably arranged in parallel, and seals between the layers (i) and (iii), which prevent the liquid from running out when filling. Layer (ii) is thus preferably arranged in an adhesive manner between layers (i) and (iii).

The liquid for the preparation of (ii) preferably contains (a) isocyanates and (b) compounds which are reactive toward isocyanates. Layer (ii) thus preferably represents polyisocyanate polyadducts. In this document, among the

Expressing "starting materials" or "starting components" in particular (a) isocyanates and (b) reactive towards isocyanates Compounds to understand, but optionally, if they are used, also (c) gases, (d) catalysts, (e) auxiliaries and / or (f) blowing agents.

The reaction of (a) with (b) to (ii) is preferably carried out in the presence of 1 to 50% by volume of gases (c). Polymer polyols are preferably used as (b). The reaction of (a) with (b) is preferably carried out in the presence of (f) blowing agents.

The polyisocyanate polyaddition products (ii) of the composite elements produced according to the invention preferably have an elastic modulus of> 275 MPa in the temperature range from -45 to + 50 ° C (according to 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) on.

The composite elements according to the invention can be prepared in such a way that between (i) and (iii) polyisocyanate polyadducts (ii), usually polyurethanes, which may have urea and / or isocyanurate structures, by reacting (a) isocyanates with ( b) compounds reactive toward isocyanates, optionally in the presence of blowing agents (f), 1 to 50% by volume, based on the volume of the polyisocyanate polyadducts, of at least one gas (c), (d) catalysts and / or (e) Manufactures aids, preferably (ii) adhering to (i) and (iii). The production of such polyisocyanate polyadducts (ii) has been described many times.

The surfaces of (i) and (iii) can preferably be blasted with corundum or iron gravel before the production of the composite elements for cleaning and increasing the surface roughness with sand or steel balls. This blasting can be carried out according to the usual methods, in which the blasting material strikes the surfaces under high pressure, for example. Suitable equipment for such treatment is commercially available.

This treatment of the surfaces of (i) and (iii) which are in contact with (ii) after the reaction of (a) with (b) leads to a significantly improved adhesion of (ii) to (i) and ( iii). The blasting is preferably carried out directly before the introduction of the components for the production of (ii) into the space between (i) and (iii). The surfaces of (i) and (iii) to which (ii) is to adhere are preferably free of inorganic and / or organic substances which reduce adhesion, for example Dust, dirt, oils and greases or substances generally known as mold release agents.

The starting materials (a), (b), (c), (d), (e) and (f) in the process according to the invention are described by way of example below:

Suitable isocyanates (a) are the known aliphatic, cycloaliphatic, araliphatic and / or aromatic iso-

10 cyanates, preferably diisocyanates, which may have been biuretized and / or isocyanurated using 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-tetra-

15 methylene diisocyanate 1,4, 2-methylpentamethylene diisocyanate 1,5, tetramethylene diisocyanate 1,4, lysine ester diisocyanates (LDI), hexamethylene diisocyanate 1,6, (HDI), cyclohexane 1,3, and / or 1,4-diisocyanate, 2,4- and 2, 6-hexahydrotoluenediisocyanate and the corresponding mixtures of isomers, 4,4'-, 2,2'- and

20 2, 4'-dicyclohexylmethane diisocyanate and the corresponding isomer mixtures, l-isocyanato-3, 3, 5-trimethyl-5-isocyanato-methylcyclohexane (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

25 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 polyphenyl-

30 polymethylene polyisocyanates used, particularly preferably mixtures containing polyphenylpolymethylene polyisocyanates and at least one of the MDI isomers.

As (b) compounds reactive toward isocyanates, "for example, compounds can be used which have hydroxyl, thiol and / or primary and / or secondary amino groups as groups reactive toward isocyanates and usually have a molecular weight of 60 to 10,000 g / mol, for example Polyols selected from the group of polymer polyols, polyether ⁴ ^ polyalcohols, polyester polyalcohols, polythioether polyols, hydroxyl group-containing polyacetals and hydroxyl group-containing aliphatic polycarbonates or mixtures of at least two of the polyols mentioned. These compounds usually have a functionality towards isocyanates of 2 to 6 and a ⁴⁵ Molecular weight of 400 to 8000 and are generally known to the person skilled in the art. Examples of suitable polyether polyalcohols are those which, according to known technology, are added to customary starter substances by 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. Known aliphatic, araliphatic, cycloaliphatic and / or aromatic compounds which contain at least one, preferably 2 to 4 hydroxyl groups and / or at least one, preferably 2 to 4 amino groups can be used as starter substances. For example, ethane diol, diethylene glycol, 1,2- or 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, glycerol, trimethylolpropane can be used as starter substances. Neopentyl glycol, sugar, for example sucrose, pentaerythritol, sorbitol, ethylenediamine, propanediamine, neopentanediamine, hexamethylenediamine, isophoronediamine, 4, 4'-diaminodicyclohexylmethane, 2- (ethylamino) ethylamine, 3- (methylamino) aminylamine, diethylenetrene Dipropylenetriamine and / or N, N ^λ bis (3-aminopropyl) ethylenediamine can be used.

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

Compounds known from polyurethane chemistry, preferably styrene-acrylonitrile graft polyols, can be used as polymer polyols, a special class of polyether polyols.

The use of polymer polyols in particular can significantly reduce the shrinkage of the polyisocyanate polyaddition product, for example the polyurethane, and thus lead to improved adhesion of (ii) to (i) and (iii). If necessary, blowing agents (f) and / or gases (c) can preferably be used as further measures to reduce the shrinkage.

Suitable polyester polyols can be prepared, for example, from organic dicarboxylic acids with 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. The polyester polyols preferably have a functionality of 2 to 4, in particular 2 to 3, and a molecular weight of 480 to 3000, preferably 600 to 2000 and in particular 600 to 1500. The composite elements according to the invention are preferably produced using polyether polyalcohols as component (b) for the reaction with the isocyanates, advantageously those with an average functionality compared to isocyanates 5 of 1.5 to 8, preferably 2 to 6, and a molecular weight of 400 to 8000.

The use of polyether polyalcohols offers considerable advantages through improved stability of the polyisocyanate poly

10 addition products against hydrolytic cleavage and due to the lower viscosity, each 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 the reaction

15 mixture for the production of (ii) containing the polyether polyalcohol enables a faster and easier filling of the space between (i) and (iii) with the reaction mixture for the production of the composite elements. Due to the considerable dimensions, particularly of structural parts in shipbuilding

20 low viscosity liquids are of considerable advantage.

In addition to the compounds mentioned, the compounds having a customary molecular weight of 400 to 8000 can optionally be used as compounds reactive toward isocyanates

25 diols and / or triols with molecular weights of 60 to <400 can be used as chain extenders and / or crosslinking agents in the process according to the invention. To modify the mechanical properties, e.g. hardness, but the addition of chain extenders, cross-linking

30 means or, if appropriate, also mixtures thereof prove to be advantageous. The chain extenders and / or crosslinking agents preferably have a molecular weight of 60 to 300. For example, aliphatic, cycloaliphatic and / or araliphatic diols with 2 to 14, preferably 4 to

35 10 carbon atoms, e.g. Ethylene glycol, propanediol-1,3, decanediol-1, 10, o-, m-, p-dihydroxycyclohexane, diethylene glycol, dipropylene glycol and preferably butanediol-1, 4, hexanediol-1, 6 and bis- (2-hydroxy-ethyl) -hydroquinone, triols, such as 1,2,4-, 1, 3, 5-trihydroxy-cyclohexane, glycerol and trimethylolpropane,

40 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 as e.g. Diethyltoluenediamine and / or 3,5-dimethylthio-2,4-toluenediamine.

45 If chain extenders, crosslinking agents or mixtures thereof are used to prepare the polyisocyanate polyaddition products, they are advantageously used in an amount of 0 to 30% by weight, preferably 1 to 30% by weight, based on the weight of the total isocyanates used reactive compounds (b).

In addition, aliphatic, araliphatic, cycloaliphatic and / or aromatic carboxylic acids can be used as (b) to optimize the curing process in the preparation 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 acids mentioned. The proportion by weight of these acids can be 0 to 5% by weight, preferably 0.2 to 2% by weight, based on the total weight of (b).

The use of A in-started polyether polyalcohols can also improve the curing behavior of the reaction mixture for the preparation of (ii). Compounds (b), like the other components for the preparation of (ii), are preferably used with the lowest possible water content in order to avoid the formation of carbon dioxide by reaction of the water with isocyanate groups.

As component (c) for the preparation of (ii), generally known compounds can be used which have a boiling point at a pressure of 1 bar of less (ie at temperatures lower than) -50 ° C., for example air, carbon dioxide, nitrogen, helium and / or neon. Air is preferably used. Component (c) is preferably inert towards component (a), particularly preferably towards components (a) and (b), ie a reactivity of the gas towards (a) and (b) is scarcely, preferably not detectable. The use of gas (c) differs fundamentally from the use of conventional blowing agents for the production of foamed polyurethanes. While conventional blowing agents (f) are used in liquid form or are soluble in the polyol component in the case of gaseous physical blowing agents) and evaporate during the reaction either due to the development of heat or in the case of water due to the reaction with the isocyanate groups Develop gaseous carbon dioxide, component (c) is preferably already used in gaseous form as an aerosol, for example in the polyol component in the present invention. Generally known compounds can be used as catalysts (d), which greatly accelerate the reaction of isocyanates with the compounds reactive towards isocyanates, preferably a total catalyst content of 0.001 to 15% by weight, in particular 0.05 to 6% by weight, based on the weight of the total isocyanate-reactive compounds used. For example, the following compounds can be used: triethylamine, tributylamine, dirnethylbenzylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, N, N, N ', N'-tetramethyl-diamino-diethyl ether, bis (dimethylaminopropyl) urea, N-methyl or N-ethylmorpholine, N-cyclohexylmorpholine, N, N, N ', N'-tetramethylethylene diamine, N, N, N', N 'tetramethylbutane diamine, N, N, N', N 'tetramethyl hexane diamine -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, dirnethylaminoethanol, 2- (N, N-dimethylaminoethoxy) ethanol, N, N ', N "-Tris- (dialkylamino-alkyl) hexahydrotriazines, for example N, N ', N "-Tris- (dimethylamino-propyl) -s-hexahydrotriazine, iron (II) chloride, zinc chloride, lead octoate and preferably tin salts, such as tin dioctoate, tin diethylhexoate, dibutyl tin dilaurate and / or dibutyldilauryltin mercaptide, 2, 3-dimethyl-3, 4,5, 6-tetrahydropyrimidine, tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, alkali metal hydroxides, such as sodium hydroxide, alkali metal alcoholates, such as sodium methylate and potassium or isopropyl alcoholate long-chain fatty acids with 10 to 20 C atoms and optionally pendant OH groups.

It has proven very advantageous to carry out the preparation of (ii) in the presence of (d) in order to accelerate the reaction.

The reaction mixture for the preparation of the polyisocyanate polyadducts (ii) can optionally (e) be incorporated with auxiliaries. Examples include fillers, surface-active substances, dyes, pigments, flame retardants, hydrolysis protection agents, fungistatic, bacteriostatic substances and foam stabilizers.

Examples of suitable surface-active substances are compounds which serve to support the homogenization of the starting materials and, if appropriate, are also suitable for regulating the structure of the plastics. Examples include emulsifiers, such as the sodium salts of castor oil sulfates or of fatty acids and salts of fatty acids A inen, for example oleic acid diethylamine, stearic acid diethanolamine, ricinoleic acid diethanolamine, salts of sulfonic acids, for example alkali or ammonium salts of dodecylbenzene or dinaphthylmethane disulfonic acid and ricinoleic acid. The surface-active substances are usually used in amounts of from 0.01 to 5% by weight, based on 100% by weight of the compounds (b) reactive toward isocyanates used in total.

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, dimethyl methane phosphonate, diethanolaminomethylphosphonic acid diethyl ester and commercially available halogen-containing flame retardant polyols. Except for the halogen-substituted ones already mentioned

Phosphates can also contain inorganic or organic flame retardants, such as red phosphorus, aluminum oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate and calcium sulfate, expandable graphite or cyanuric acid derivatives, e.g. Melamine, or mixtures of at least two flame retardants, e.g. Ammonium polyphosphates and melamine and optionally corn starch or ammonium polyphosphate, melamine and expandable graphite and / or optionally aromatic polyesters can be used to flame retard the polyisocyanate polyaddition products. In general, it has proven to be expedient to use 5 to 50% by weight, preferably 5 to 25% by weight, of the flame retardants mentioned, based on the weight of the compounds used which are reactive toward isocyanates.

Fillers, in particular reinforcing fillers, are understood to be the conventional organic and inorganic fillers, reinforcing agents, weighting agents, agents for improving the abrasion behavior in paints, coating agents, etc., which are known per se. Examples include: inorganic fillers such as silicate minerals, for example sheet silicates such as antigorite, serpentine, hornblende, amphibole, chrisotile and talc, metal oxides such as kaolin, aluminum oxides, titanium oxides and iron oxides, metal salts such as chalk, heavy spar and inorganic pigments, such as cadmium sulfide and zinc sulfide, and glass and others. Kaolin (china clay), aluminum silicate and coprecipitates made from barium sulfate and aluminum silicate and natural and synthetic fibrous minerals such as wollastonite, metal and glass fibers of short length are preferably used. Examples of suitable organic fillers are: carbon, melamine, rosin, cyclopentadienyl resins and graft polymers as well as cellulose fibers, polyamide, polyacrylonitrile, polyurethane, polyester fibers based on aromatic and / or aliphatic dicarboxylic acid esters and in particular carbon fibers. The inorganic and organic fillers can be used individually or as mixtures.

10 to 70% by weight of fillers, based on the weight of (ii), are preferably used as (e) auxiliaries in the preparation of (ii). Talc, kaolin, calcium carbonate, heavy spar, glass fibers and / or micro glass balls are preferably used as fillers. The size of the particles of the fillers should preferably be chosen so that the introduction of the components for the production of (ii) into the space between (i) and (iii) is not hindered. The fillers particularly preferably have particle sizes of <0.5 mm.

The fillers are preferably used in a mixture with the polyol component in the reaction for the production of the polyisocyanate polyaddition products.

The fillers can be used to reduce the thermal expansion coefficient of the polyisocyanate polyaddition products, which is greater than that of steel, for example, and thus to match that of the steel. This is particularly advantageous for a permanently strong bond between the layers (i), (ii) and (iii), since this results in lower stresses between the layers under thermal stress.

For the preparation of (ii), customary foam stabilizers which are commercially available and are generally known to the person skilled in the art are preferably used as (e), for example generally known polysiloxane-polyoxyalkylene block copolymers, e.g. Tegostab 2219 from Goldschmidt. The proportion of these foam stabilizers in the preparation of (ii) is preferably 0.001 to 10% by weight, particularly preferably 0.01 to 10% by weight, in particular 0.01 to 2% by weight, based on the weight of the for the production of (ii) components (b), (e) and optionally (d). The use of these foam stabilizers has the effect that component (c) in the reaction mixture is stabilized to produce (ii).

Blowing agents (f) known from polyurethane chemistry can be used as blowing agents, for example physical and / or chemical blowing agents. Physical blowing agents of this type generally have a boiling point at a pressure of 1 bar of greater than (ie at temperatures higher than) -50 ° C. Examples of physical blowing agents are, for example, CFCs, HCFCs, HFCs, aliphatic hydrocarbons, cycloaliphatic hydrocarbons, with 4 to 6 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), tetrafluoroethane (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.e. Blowing agents which are gaseous due to a reaction, for example with isocyanate groups

Form products, come for example water, hydrated compounds, carboxylic acids, tertiary alcohols, e.g. t-butanol, carbamates, for example those in the document

EP-A 1000955, in particular on pages 2, lines 5 to 31 and page 3, lines 21 to 42, describes carbamates,

Carbonates, e.g. Ammonium carbonate and / or ammonium hydrogen carbonate and / or guanidine carbamate.

Water and / or carbamates are preferably used as blowing agents (f).

The blowing agents (f) are preferably used in an amount which is 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 familiar 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 components (a), (b) and, if appropriate, (c), (d), (e) and / or (f) used to produce (ii).

To produce the polyisocyanate polyaddition products according to the invention, the isocyanates and the compounds which are reactive toward isocyanates are reacted in amounts such that the equivalence ratio of NCO groups of the isocyanates (a) to the sum of the reactive hydrogen atoms of the compounds which are reactive toward isocyanates ( 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 contain isocyanurate groups, a ratio of NCO groups to the sum of the reactive hydrogen atoms of 1.5 to 60: 1, preferably 1.5 to 8: 1, is usually used. The polyisocyanate polyaddition products are usually produced by the one-shot process or by the prepolymer process, for example with the aid of high-pressure or low-pressure technology.

It has proven to be particularly advantageous to work according to the two-component process and the compounds (b) reactive towards isocyanates, optionally the blowing agents (f) and optionally the catalysts (d) and / or auxiliaries (e) in the component (A) ( Polyol component) to combine and preferably to mix intimately and to use the isocyanates (a) as component (B).

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

The corresponding component can be mixed with (c) by generally known methods. For example, (c) can be compressed by generally known loading devices, for example air loading devices, preferably under pressure, for example from a pressure vessel or by a compressor, e.g. are supplied through a nozzle to the corresponding component. The corresponding components are preferably thoroughly mixed with (c), so that gas bubbles of (c) in the usually liquid component preferably have a size of 0.0001 to 10, particularly preferably 0.0001 to 1 mm.

The content of (c) in the reaction mixture for the preparation of (ii) can be determined in the return line of the high-pressure machine using generally known measuring devices via the density of the reaction mixture. The content of (c) in the reaction mixture can preferably be regulated automatically on the basis of this density via a control unit. The component density can be determined and regulated online during the normal circulation of the material in the machine, even at a very low circulation speed.

The composite elements obtainable according to the invention are used above all in areas in which construction elements are required which can withstand great forces, for example as construction parts in shipbuilding, for example in ship hulls, for example double hulls with an outer and an inner wall, and cargo space covers, cargo space partitions, loading fold or in buildings, for example bridges or as construction elements in house construction, especially in high-rise buildings.

The composite elements according to the invention are not to be confused with classic sandwich elements, which contain a polyurethane and / or polyisocyanurate rigid foam as the core and are usually used for thermal insulation. Known sandwich elements of this type would not be suitable for the named areas of application due to their comparatively lower mechanical strength.

Claims

claims

1. A method for introducing liquids by means of a conveyor into a mold which has an upper layer (i) with at least one opening (iv) through which liquid is filled, and a lower layer (iii), characterized in that the Outflow end of the conveying device or a holder for the outflow end of the conveying device is screwed to the layer (i) at at least three points.

2. The method according to claim 1, characterized in that a holder is screwed to at least three threads which are attached to (i) and the outflow end is fixed on this holder.

3. The method according to claim 1 or 2, characterized in that one shoots bolts with a thread, which serve for fastening the outflow end or the holder, into the layer (i).

4. The method according to claim 1, characterized in that the outflow end is a mixing head.

5. The method according to claim 4, characterized in that one fixes an O-ring made of an elastic material between the layer (i) and the mixing head.

6. The method according to claim 4, characterized in that the liquids are introduced by means of a high-pressure apparatus via the mixing head.

7. The method according to claim 1, characterized in that the liquid by means of the conveyor continuously without interruption in a single step in the space to be filled between (i) and (iii).

8. The method according to claim 1, characterized in that (i) and / or (iii) in addition to the or the openings (iv) through which the liquids are introduced, have at least one further opening (v).

9. The method according to claim 8, characterized in that overflow vessels are attached to the one or more openings (v), the complete filling of the space between (i) and (iii) is determined on the rise of the liquid in the overflow vessels, and then the opening (en) (v) closed.

10. The method according to claim 1, characterized in that the method is used to produce composite elements which have the following layer structure:

(i) 2 to 20 mm of metal, plastic or wood, (ii) 10 to 300 mm of a plastic that results from hardening of the liquid filled in the mold, (iii) 2 to 20 mm of metal, plastic or wood.

11. The method according to claim 10, characterized in that the liquid for the preparation of (ii) (a) isocyanates and (b) isocyanate-reactive compounds and (ii) are polyisocyanate polyadducts.

12. The method according to claim 11, characterized in that one carries out the reaction of (a) with (b) to (ii) in the presence of 1 to 50% by volume of gases (c).

13. The method according to claim 11, characterized in that one uses as (b) polymer polyols.

14. The method according to claim 11, characterized in that one carries out the reaction of (a) with (b) in the presence of (f) blowing agents.

15. Composite elements obtainable by a method according to one of claims 1 to 14.