METHOD FOR PRODUCING A POLYISOCYANURATE COMPOSITE MATERIAL

Description

[0001] The present invention relates to a process for producing polyisocyanurate composite materials, the polyisocyanurate composite materials obtainable therefrom, and the use of such polyisocyanurate composite materials for producing components, as well as components consisting of or containing a polyisocyanurate composite material according to the invention. The invention is set forth in the appended set of claims.

[0002] Fiber-reinforced composite materials, consisting of a polymer matrix and a fibrous filler, are predominantly used as lightweight construction materials, for example, in automotive, shipbuilding, aircraft construction, sports, the construction industry, the oil industry, and the electrical and energy sectors. While the polymer matrix fixes the fibrous filler, ensures load transfer, and protects the fibrous filler from environmental influences, the function of the fibrous filler, for example, is to conduct the load along the fiber.

[0003] By appropriately combining polymer matrix and fibrous filler, fiber-reinforced composite materials can be obtained which exhibit improved mechanical and physical properties compared to the polymer matrix alone.

[0004] Typically, unsaturated polyester (UP) and polyvinyl (VP) resins, epoxies, and, more recently, aromatic polyurethane (PU) systems are used as polymer matrix materials for fiber-reinforced composite materials. These known polymer matrix materials have the disadvantage that they are not sufficiently weather-resistant in the composite material and therefore usually require a weather-resistant coating for outdoor use. Such coating can be associated with considerable effort, as the weather-resistant coating often adheres poorly to the surface of the fiber-reinforced composite material, especially if release agents were used during component manufacture. The provision of composite materials with good weather resistance is therefore desirable.

[0005] Polymers with polyisocyanurate structural components are generally known for their good temperature and chemical resistance. Polyurethane coatings with polyisocyanurate components based on aliphatic isocyanates, in particular, also exhibit very high weather resistance. However, the complete trimerization of diisocyanates to polyisocyanurate plastics is difficult to control. For this reason, aliphatic polyisocyanurates are typically used only as crosslinking agents for polyurethane systems in coatings and adhesives chemistry. During their production, the trimerization reaction is stopped at low conversions and excess unreacted monomeric diisocyanate is removed.For example, DE 31 00 263; GB 952 931, GB 966 338; US 3 211 703, US 3 330 828, EP 0 056 159 B1, and DE 32 19 608 A1 stipulate that, in the production of crosslinking agents based on polyisocyanurates, starting from aliphatic and mixed aliphatic and aromatic monomeric diisocyanates, the reaction should either be carried out in dilution or only at low conversion values with very precise temperature control. This deliberately does not produce fully crosslinked polyisocyanurate plastics, but only oligomeric, low-viscosity, soluble products.

[0006] There have also been attempts to synthesize fully cross-linked polyisocyanurate plastics based on aliphatic weather-resistant isocyanates.

[0007] For example, European Polymer Journal, Vol. 16, 147-148 (1980 )the very slow catalytic trimerization of monomeric 1,6-diisocyanatohexane (HDI) at low temperatures of 40 °C to form a clear, transparent polyisocyanurate plastic. However, this requires very high catalyst concentrations of dibutyltin dimethoxide (approx. 10 wt.%) as a trimerization catalyst, which has a severely negative impact on the thermal stability and color stability of the products. The glass transition temperature (Tg) and the thermal heat distortion temperature were not investigated. The content of free isocyanate groups within the solid was not determined. Only the tensile shear strength at room temperature was determined and showed relatively low values. Other diisocyanates such as IPDI, TDI, or MDI did not produce solids. In addition, the long reaction time required is uneconomical and therefore unsuitable for many processing processes.

[0008] European Polymer Journal, Vol. 16, 831-833 (1980 )describes the trimerization of monomeric HDI to a solid polyisocyanurate at a temperature of 140 °C using 6 wt.% tributyltin oxide as an extremely inert catalyst. However, the exact conversion of the NCO groups and the properties of this solid are not further described.

[0009] Theo Flipsen's dissertation, "Design, synthesis and properties of new materials based on densely crosslinked polymers for polymer optical fiber and amplifier applications," Rijksuniversiteit Groningen, 2000, describes the trimerization of monomeric HDI using a neodymium / crown ether complex as a catalyst. The resulting polyisocyanurate, which is said to exhibit good optical, thermal, and mechanical properties, was investigated for its suitability for optical applications, particularly as a polymer light guide, as part of the dissertation. According to Flipsen, highly transparent polyisocyanurates with a glass transition temperature (T g ) of 140 °C are only obtained under ideal conditions using a soluble neodymium crown ether catalyst and a pre-reaction at 60 °C or room temperature, followed by a post-reaction at temperatures up to 140 °C over a long period of more than 24 hours.A disadvantage of the described process is that it is a slow, multi-step process with a complex reaction regime, making it difficult to implement on a large scale. Furthermore, the neodymium / crown ether complex used as a catalyst is very expensive and therefore uneconomical for use in a large-scale process. Furthermore, the work of Theo Flipsen has shown that monomeric HDI is always present throughout the trimerization reaction. Therefore, it cannot be completely ruled out that the finished polyisocyanurate composite material also contains small amounts of free monomeric HDI, which migrate to the surface over time and enter the human body through contact or evaporation.For safe handling of the finished polyisocyanurate composite material components, it is therefore desirable that no monomers are released from the finished polyisocyanurate plastic or, better yet, that no monomers are used in its production at all.

[0010] GB 1 335 958 describes the production of a polyisocyanurate composite material by impregnating glass fiber fabric with a 2:1 mixture of methylenediphenyl isocyanate (MDI) and trimethylhexamethylenediamine (TMHDI) in the presence of a benzyldimethylamine / phenylglycidyl ether mixture as a catalyst. The polyisocyanurate plastic was cured using a complex temperature control over a long period of time: 16 hours at 50°C, 1 hour at 100°C, 1 hour at 150°C, and 3 hours at 180°C. The described process takes a very long time and is difficult to implement on an industrial scale due to the complex reaction process.

[0011] European Polymer Journal, Vol. 14, 675-678 (1978) describes the production of both HDI-based polyisocyanurate solids and polyisocyanurate composites. These exhibited similar or superior properties compared to polyester or epoxy composites. However, this process, with the required long reaction times of more than 24 hours at an optimal catalyst concentration of approximately 0.5 wt.% bis(tributyltin) oxide, is industrially uneconomical and therefore impractical.

[0012] WO 2015 / 166983 describes the use of isocyanurate plastics for the production of encapsulants for LEDs. The production process is based on the polymerization of oligomeric polyisocyanates. Only small volume bodies are produced. The use of polyethers to activate a catalyst is not disclosed.

[0013] US 6,133,397 describes coatings, but not solid bodies, composed of polyisocyanurates obtained by polymerization of oligomeric polyisocyanates.

[0014] WO 2015 / 197739 describes the production of composite materials based on polyisocyanate compositions with a monomer content of at least 60 wt. Nor does it describe polyisocyanate compositions consisting of at least 70 wt. % oligomeric polyisocyanates with aliphatically or cycloaliphatically bound isocyanate groups.

[0015] In patent application US 2009 / 005517 A1, Bleys et al. describe the production of polyisocyanurate composite materials. However, they only list examples based on aromatic polyisocyanates. These are known to exhibit poor weathering behavior. Analytical results for the aromatic polyisocyanurate composite materials produced were not mentioned. Furthermore, the table in Example 5 shows that polyethylene glycols (EO polyethers) in the catalyst system, when pure aromatic polyisocyanates are used, lead to very short pot lives (well under 800 seconds), which make practical application difficult or impossible. No studies or theoretical discussions on aliphatic polyisocyanates and their possible differences from aromatic isocyanates were conducted.The advantages of using aliphatic polyisocyanates to extend pot life and improve weathering properties, or even the combination of polyethylene glycols (EO polyethers) with alkaline metal salts and aliphatic polyisocyanates were not mentioned or described.

[0016] The production of polyisocyanurate plastics is described in the prior art mainly starting from liquid monomeric diisocyanates (e.g. stearyl diisocyanate, dodecyl diisocyanate, decyl diisocyanate, nonyl diisocyanate, octyl diisocyanate, HDI, BDI, PDI, IPDI, H12MDI, TDI, MDI, NDI, NBDI), both aliphatic and aromatic in nature. The heat of the trimerization reaction to polyisocyanurates is so high (-75 kJ / mol NCO) that a reaction starting from monomeric polyisocyanates, especially with inexpensive, monomeric polyisocyanates with a high isocyanate content (e.g. 1,4-butane diisocyanate (BDI), 1,5-pentamethylene diisocyanate (PDI), 1,6-hexymethylene diisocyanate (HDI), triisocyanatononane (TIN)) cannot be carried out in practice. This is especially true with regard to the large scale required for industrial applications and adiabatic conditions, as they typically occur inside volume bodies in highly exothermic polymerization processes.In the state of the art, trimerization has therefore only been carried out in small amounts of substance under strict temperature control.

[0017] An adiabatic change of state is a thermodynamic process in which a system is transformed from one state to another without exchanging heat energy with its surroundings. "Adiabatic conditions" here mean that the reaction heat released during the exothermic reaction cannot be completely dissipated to the surroundings. Thus, homogeneous conditions typically cannot be achieved in solids, and "adiabatic" conditions prevail, especially in the interior of solids during rapid reactions, which can lead to a strong local temperature increase during exothermic reactions. These local hotspots are extremely critical when it comes to producing functionally homogeneous products.

[0018] A further problem is that aromatic monomeric diisocyanates and many aryl aromatic or alicyclic monomeric diisocyanates can only be homo- and co-trimerized to low conversions. Plasticizing or co-solving reactants must often be added. Otherwise, the reaction freezes at high residual isocyanate levels, and cloudy and discolored products are typically obtained. The use of plasticizing and co-solving reactants is disadvantageous, as they lead to less chemically and thermally inert structural elements such as allophanates, ureas, urethanes, thiourethanes, and oxazolidinones, polyesters, and polyethers. At high temperatures, they lead to uretdiones with subsequent carbodiimidization and carbon dioxide elimination, as well as to asymmetric isocyanurates. The production of polyisocyanurate plastics that contain predominantly or exclusively isocyanurate structures as structural elements is therefore not possible.

[0019] Temperature control, especially down to the smallest volume element of the molded body, is of enormous importance in the production of highly converted polyisocyanurate plastics. Due to the high isocyanate content of the monomeric starting products, temperatures locally exceeding 300 °C can occur under adiabatic conditions, as typically prevailing in trimerizations in volume bodies, due to the exothermic reaction. For example, temperatures above the flash point of monomeric HDI at 140 °C and the boiling point of monomeric HDI at 255 °C, and even up to the autoignition temperature of HDI at 454 °C, can occur due to the exothermic reaction. Thus, the high temperatures can lead to direct decomposition of the products and even to in situ evaporation and self-ignition of the monomeric polyisocyanates.

[0020] In addition to the occupational health disadvantages caused by the released monomeric diisocyanates or decomposition products, the formation of bubbles at higher temperatures is a problem. Bubble formation occurs, for example, due to side reactions such as uretdione formation and subsequent carbodiimidization with the release of carbon dioxide. The polyisocyanurate plastic solids produced from the monomeric diisocyanates therefore typically exhibit bubbles, are dark in color, and thus cannot meet certain specifications regarding appearance, density, electrical insulation behavior, and mechanical properties.

[0021] A common feature of the above-mentioned processes is that the trimerization is initiated at low temperatures. Higher trimerization temperatures, especially at the beginning of the trimerization, are difficult to control when starting from monomeric polyisocyanates and lead to significant side reactions in the form of uretdiones and carbodiimides, thus causing blistering due to carbon dioxide release and discoloration of the resulting product. The only exception is trimerization in the presence of high concentrations of extremely inert catalysts such as tributyltin oxide. The preliminary reactions carried out in this way, typically lasting several hours and resulting in low isocyanate conversions of approximately 50% at temperatures above 100 °C, are too complex for the production of polyisocyanurate composite materials and are therefore not of industrial interest.

[0022] Furthermore, the described processes have in common that they are not suitable for obtaining highly converted polyisocyanurate composite materials in efficient industrial processes, especially under adiabatic conditions, such as those typically encountered inside solid bodies during highly exothermic reactions. This applies especially to those that are largely free of disruptive defects such as discoloration, inhomogeneities, and unwanted bubbles, and that exhibit good weathering stability, good mechanical properties such as a high glass transition temperature (Tg) and high tensile strength. Furthermore, the processes known from the prior art cannot be used to polymerize in open reaction vessels at elevated temperatures without risking a significant release of monomeric diisocyanates into the environment.In contrast, technically efficient processes are characterized by high conversion rates and a high level of occupational hygiene and reproducibility.

[0023] Due to the difficulty of controlling the trimerization of monomeric isocyanates to polyisocyanurate plastics, their practical application as polymer matrix materials in composite materials has so far been of no commercial significance, despite their excellent weather resistance. To the extent that fiber-reinforced polyisocyanurate composite materials are known at all, they appear to require improvement with regard to the manufacturing conditions of the polyisocyanurate matrix material, such as reaction time and control.

[0024] The invention was therefore based on the object of providing a practical, easy-to-implement, efficient technical process for producing weather-resistant fiber-reinforced polyisocyanurate composite materials, characterized in particular by short reaction times and simple reaction control. Furthermore, the resulting fiber-reinforced polyisocyanurate composite materials should be largely free of disruptive defects such as discoloration, inhomogeneities, and unwanted bubbles.

[0025] This object is achieved according to the invention by the process for producing a polyisocyanurate composite material according to claim 1 and the polyisocyanurate composite material obtainable therefrom according to claim 12.

[0026] Advantageous embodiments of the invention are specified in the dependent claims and, like the general inventive concept, are explained in detail below. The invention relates to a process for producing a polyisocyanurate composite material, comprising the following steps: a) providing a polyisocyanate composition A) which contains oligomeric polyisocyanates and is low in monomeric diisocyanates, where low in monomeric diisocyanates means that the polyisocyanate composition A) has a monomeric diisocyanate content of at most 20% by weight and consists of at least 70% by weight of oligomeric polyisocyanates with exclusively aliphatically or cycloaliphatically bound isocyanate groups, and b) catalytic trimerization of the polyisocyanate composition A) in the presence of at least one fibrous filler B) and a trimerization catalyst C) to form the polyisocyanurate composite material, wherein the trimerization catalyst C) is present in a concentration of 0.04 to 15.0 wt.% based on the amount of polyisocyanate composition A, and wherein the trimerization catalyst C) is an alkaline alkali or alkaline earth metal salt which, as a saturated aqueous solution, has a pH of greater than 7 at 23°C, and contains a polyether; and wherein, for the concentration calculation for the trimerization catalyst C), only the mixture of the at least one alkali or alkaline earth metal and the at least one polyether is considered.

[0027] The invention further relates to the polyisocyanurate composite materials obtainable by the process and to their use for producing components and components consisting of or containing a polyisocyanurate composite material according to the invention.

[0028] Surprisingly, it was discovered that oligomeric polyisocyanates, known as crosslinkers in coatings chemistry, can be polymerized rapidly and efficiently, even under adiabatic conditions, in the presence of quaternary ammonium and / or metal salts as catalysts, particularly potassium acetate with complexing agents, and fibrous fillers to form polyisocyanurate composite materials with excellent weathering and chemical resistance, as well as high temperature resistance and good mechanical properties. Likewise, when using oligomeric polyisocyanates, even under adiabatic temperature control, side reactions that lead to bubbles, inhomogeneities, and especially discoloration are largely suppressed, and the reaction can be carried out reproducibly and in a controlled manner.The process according to the invention allows the production of polyisocyanurate composite materials under quasi-adiabatic conditions without the materials used or desired reaction products being decomposed or heated above their boiling point.

[0029] In contrast to the processes described in the prior art, trimerization by the process according to the invention can also be carried out at high temperatures and short reaction times, without the disadvantages observed in the prior art, such as blistering and discoloration. Practical experiments have shown, for example, that complete trimerization can be carried out at temperatures well above 100 °C. Trimerization can be carried out particularly advantageously at temperatures above the glass transition temperature of the desired products. Furthermore, practical experiments have shown that complete trimerization by the process according to the invention is possible with reaction times of, for example, well under 30 minutes.

[0030] In contrast to the prior art processes, trimerization according to the process of the invention can be carried out in open reaction systems without risking a significant release of monomeric diisocyanates into the environment. This offers particular advantages in terms of occupational hygiene and allows for cost-efficient process operation.

[0031] A further advantage of the process according to the invention with a low monomer content is that the volume shrinkage during crosslinking of the resin to form the finished component or solid body is very low and thus components can be manufactured with high dimensional accuracy and low internal stresses.

[0032] In the specialist's view, volume shrinkage refers to a change in volume during the crosslinking of the resin to form the plastic, due to the difference in density between the reactive resin and the cured plastic. Typically, the density of the resin is lower than that of the crosslinked plastic, meaning the volume decreases during curing (volume shrinkage). This changes the external dimensions, and internal stresses can occur in the component, which affect the mechanical properties.

[0033] When reference is made here to a "solid body," this refers to a body in which, due to its volume, complete dissipation of the heat generated during the trimerization reaction to the environment is not possible quickly enough. Consequently, local hotspots can occur inside the solid body, i.e., the trimerization reaction generates more energy in a given time than can be dissipated to the environment in that time. In particular, a "solid body," as used here, is a body that has a thickness of at least 0.1 mm, preferably at least 0.5 mm, more preferably at least 1 mm, in particular at least 2 mm, and most preferably at least 5 mm in its smallest dimension. In particular, a "solid body," as used here, is not a film, lacquer layer, or membrane.

[0034] A "polyisocyanurate composite," as used herein, is a composite material whose polymeric matrix material is a plastic containing polyisocyanurate. The polymeric matrix material may also consist predominantly or entirely of a polyisocyanurate. A polymeric matrix material made of blends of polyisocyanurates and other plastics also falls under the term "polyisocyanurate composite material," as used herein.

[0035] When we speak of "material" here, we mean a product that is largely dimensionally stable at room temperature—unlike, for example, gels or liquids. The term "material," as used here, encompasses all common plastic classes, including, in particular, thermosets, thermoplastics, and elastomers.

[0036] When reference is made here to "polyisocyanate composition A)" and in particular to "providing the polyisocyanate composition A)", this means that the polyisocyanate composition A) exists and is used as a reactant.

[0037] A "polyisocyanurate," as used herein, is any molecule that has a plurality of isocyanurate structural units, for example, at least ten isocyanurate structural units. A molecule with a single isocyanurate structural unit may be referred to as an "isocyanurate."

[0038] The characteristic cyclic isocyanurate structural unit is represented by the following structural formula:

[0039] Isocyanurates and polyisocyanurates can be obtained by cyclotrimerization of isocyanates and polyisocyanates. The conventional cyclotrimerization starting from monomeric diisocyanates is – as described above – a highly exothermic reaction. This can significantly limit the possible applications and the technically and efficiently achievable degrees of trimerization.

[0040] The term "polyisocyanate," as used here, is a collective term for compounds containing two or more isocyanate groups (by which the skilled person understands free isocyanate groups of the general structure -N=C=O) in the molecule. The simplest and most important representatives of these polyisocyanates are diisocyanates. These have the general structure O=C=NRN=C=O, where R usually represents aliphatic, alicyclic, and / or aromatic radicals.

[0041] Due to their multiple functionality (≥ 2 isocyanate groups), polyisocyanates can be used to produce a variety of polymers (e.g. polyurethanes, polyureas and polyisocyanurates) and low molecular weight compounds (e.g. urethane prepolymers or those with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure).

[0042] When "polyisocyanates" are referred to generally here, this refers to monomeric and / or oligomeric polyisocyanates. However, for understanding many aspects of the invention, it is important to distinguish between monomeric diisocyanates and oligomeric polyisocyanates. When "oligomeric polyisocyanates" are referred to here, this refers to polyisocyanates composed of at least two monomeric diisocyanate molecules, i.e., compounds that represent or contain a reaction product of at least two monomeric diisocyanate molecules.

[0043] The production of oligomeric polyisocyanates from monomeric diisocyanates is also referred to here as the modification of monomeric diisocyanates. This "modification," as used here, refers to the reaction of monomeric diisocyanates to form oligomeric polyisocyanates with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures.

[0044] For example, hexamethylene diisocyanate (HDI) is a "monomeric diisocyanate" because it contains two isocyanate groups and is not a reaction product of at least two polyisocyanate molecules:

[0045] Reaction products of at least two HDI molecules that still contain at least two isocyanate groups are, in contrast, "oligomeric polyisocyanates" within the meaning of the invention. Examples of such "oligomeric polyisocyanates" based on monomeric HDI include HDI isocyanurate and HDI biuret, each of which is composed of three monomeric HDI building blocks: (idealized structural formulas)

[0046] For the purposes of the invention, "polyisocyanate composition A)" refers to the isocyanate component in the initial reaction mixture. In other words, it is the sum of all compounds in the initial reaction mixture that contain isocyanate groups. The polyisocyanate composition A) is therefore used as a reactant in the process according to the invention. When reference is made here to "polyisocyanate composition A)," in particular to "providing the polyisocyanate composition A)," this means that the polyisocyanate composition A) exists and is used as a reactant.

[0047] According to the invention, the polyisocyanate composition A) contains oligomeric polyisocyanates and is low in monomeric diisocyanates, where low in monomeric diisocyanates means that the polyisocyanate composition A) has a content of monomeric diisocyanates of at most 20 wt.%.

[0048] "Low in monomer" and "low in monomeric polyisocyanates" are used synonymously here with reference to the polyisocyanate composition A).

[0049] According to one embodiment of the invention, the polyisocyanate composition A) consists entirely or to an extent of at least 90, 95, 98, 99 or 99.5 wt. %, based in each case on the weight of the polyisocyanate composition A), of oligomeric polyisocyanates. Preferably, the polyisocyanate composition A) consists entirely or to an extent of at least 99.7, 99.8, or 99.9 wt. %, based in each case on the weight of the polyisocyanate composition A), of oligomeric polyisocyanates. This content of oligomeric polyisocyanates relates to the polyisocyanate composition A), ie these are not formed as intermediates during the process according to the invention, but are already present at the beginning of the reaction in the polyisocyanate composition A) used as starting material.

[0050] The polyisocyanate composition A) used is low in monomers. In practice, this can be achieved in particular by using oligomeric polyisocyanates as polyisocyanate composition A), the preparation of which always involves at least one further process step following the actual modification reaction to separate the unreacted excess monomeric polyisocyanates. This monomer separation can be carried out particularly practically using conventional methods, preferably by thin-film distillation under high vacuum or by extraction with suitable solvents inert toward isocyanate groups, for example, aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane, or cyclohexane.

[0051] According to one embodiment of the invention, the polyisocyanate composition A) according to the invention is obtained by modifying monomeric polyisocyanates with subsequent separation of unreacted monomers.

[0052] The processes described in the prior art for the production of polyisocyanurate plastics largely use monomeric polyisocyanates, ie monomeric diisocyanates, as starting materials, ie pure monomeric polyisocyanates or monomer-rich polyisocyanate compositions are catalytically trimerized.

[0053] According to one embodiment of the invention, the polyisocyanate composition A) contains oligomeric polyisocyanates and has a maximum of 20, 15, 10, 5, 4, 3, 2, 1, or 0.5 wt. %, based in each case on the weight of the polyisocyanate composition A), of monomeric polyisocyanates. Preferably, the polyisocyanate composition A) contains oligomeric polyisocyanates and has a maximum of 0.3, 0.2, or 0.1 wt. %, based in each case on the weight of the polyisocyanate composition A), of monomeric polyisocyanates.

[0054] According to a particular embodiment of the invention, a polymer composition A) containing oligomeric polyisocyanates and free or substantially free of monomeric polyisocyanates is used. "Substantially free" means that the content of monomeric polyisocyanates is at most 0.5 wt.%, based on the weight of the polyisocyanate composition A). Surprisingly, this leads to significantly lower volume shrinkage. The lower exothermicity of this reaction also allows high-quality polyisocyanurate plastics to be obtained despite faster and more drastic reaction conditions.

[0055] According to a further particular embodiment of the invention, the polyisocyanate composition A) can contain one or more monomeric external diisocyanates. Monomeric external diisocyanate means that it differs from the monomeric polyisocyanates used to produce the oligomeric polyisocyanates contained in the polyisocyanate composition A). Addition of monomeric external diisocyanate can be advantageous during processing to achieve special technical effects, such as a particular hardness, a desired elasticity or elongation, a desired glass transition temperature or viscosity. Particularly practical results are achieved when the polyisocyanate composition A) has a proportion of monomeric external diisocyanate in the polyisocyanate composition A) of at most 20 wt. %, in particular at most 15 wt. % or at most 10 wt. %, based in each case on the weight of the polyisocyanate composition A).The polyisocyanate composition A) preferably has a content of monomeric foreign diisocyanate of at most 5% by weight, preferably at most 2.0% by weight, particularly preferably at most 1.0% by weight, in each case based on the weight of the polyisocyanate composition A).

[0056] According to a further particular embodiment of the process according to the invention, the polyisocyanate composition A) can contain monomeric monoisocyanates with an isocyanate functionality of 1 or monomeric isocyanates with an isocyanate functionality greater than 2, i.e., with more than two isocyanate groups per molecule. The addition of monomeric monoisocyanates with an isocyanate functionality of 1 or monomeric isocyanates with an isocyanate functionality greater than two has proven advantageous for influencing the network density and / or glass transition temperature of the polyisocyanurate plastic. The average isocyanate functionality of the polyisocyanate composition A) is greater than 1, preferably greater than 1.25, in particular greater than 1.5, particularly preferably greater than 1.75, and most preferably greater than 2.The average isocyanate functionality of the polyisocyanate composition A) can be calculated by dividing the sum of the isocyanate functionalities of all polyisocyanate molecules contained in the polyisocyanate composition A) by the number of polyisocyanate molecules contained in the polyisocyanate composition A). Particularly practical results are obtained when the polyisocyanate composition A) contains a proportion of monomeric monoisocyanates with an isocyanate functionality of 1 or monomeric isocyanates with an isocyanate functionality greater than two in the polyisocyanate composition A) of at most 20 wt.%, in particular at most 15 wt.% or at most 10 wt.%, based in each case on the weight of the polyisocyanate composition A).The polyisocyanate composition A) preferably has a content of monomeric monoisocyanates having an isocyanate functionality of 1 or monomeric isocyanates having an isocyanate functionality greater than 2 of at most 5 wt. %, preferably at most 2.0 wt. %, particularly preferably at most 1.0 wt. %, based in each case on the weight of the polyisocyanate composition A). Preferably, no monomeric monoisocyanate having an isocyanate functionality of 1 or monomeric isocyanate having an isocyanate functionality greater than 2 is used in the trimerization reaction according to the invention.

[0057] The oligomeric polyisocyanates described here are usually obtained by modifying simple aliphatic, cycloaliphatic, araliphatic and / or aromatic monomeric diisocyanates or mixtures of such monomeric diisocyanates.

[0058] According to the invention, the oligomeric polyisocyanates may, in particular, have uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures. According to one embodiment of the invention, the oligomeric polyisocyanates have at least one of the following oligomeric structure types or mixtures thereof:

[0059] Surprisingly, it has been found that it can be advantageous to use oligomeric polyisocyanates that represent a mixture of at least two oligomeric polyisocyanates, wherein the at least two oligomeric polyisocyanates differ in their structure. This structure is preferably selected from the group consisting of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione, and oxadiazinetrione structures, and mixtures thereof. Such starting mixtures can influence the Tg value, particularly compared to trimerization reactions with oligomeric polyisocyanates of only one defined structure, which is advantageous for many applications.

[0060] Preferably, a polyisocyanate composition A) consisting of at least one oligomeric polyisocyanate having a biuret, allophanate, isocyanurate, and / or iminooxadiazinedione structure, and mixtures thereof, is used in the process according to the invention. Preferably, a polyisocyanate composition A) containing at most 50 mol%, preferably at most 40 mol%, particularly preferably at most 30 mol%, very particularly preferably at most 20 mol%, 10 mol%, 5 mol%, 3 mol%, 2 mol%, or 1 mol%, in particular no oligomeric polyisocyanurates having a urethane structure, such as, for example, urethane prepolymers, is used in the process according to the invention.

[0061] According to another embodiment, the polyisocyanate composition A) containing oligomeric polyisocyanates is one containing only a single, defined oligomeric structure, for example, exclusively or predominantly an isocyanurate structure. However, due to the manufacturing process, several different oligomeric structures are generally present side by side in the polyisocyanate composition A).

[0062] In the context of the present invention, a polyisocyanate composition A) is regarded as a polyisocyanate composition of a single defined oligomeric structure if an oligomeric structure selected from uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure is present to an extent of at least 50 mol%, preferably 60 mol%, more preferably 70 mol%, particularly preferably 80 mol%, in particular 90 mol%, in each case based on the sum of the oligomeric structures present from the group consisting of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure in the polyisocyanate composition A).

[0063] In the process according to the invention, according to a further embodiment, a polyisocyanate composition A) of a single defined oligomeric structure is used, wherein the oligomeric structure is selected from uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure and is present in the polyisocyanate composition A) to an extent of at least 50 mol%, preferably 60 mol%, more preferably 70 mol%, particularly preferably 80 mol%, in particular 90 mol%, based in each case on the sum of the oligomeric structures present from the group consisting of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure.

[0064] According to a further embodiment, the oligomeric polyisocyanates are those that primarily have an isocyanurate structure and may contain the above-mentioned uretdione, urethane, allophanate, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures only as by-products. Thus, one embodiment of the invention provides for the use of a polymer composition A) of a single, defined oligomeric structure, wherein the oligomeric structure is an isocyanurate structure and is present in the polyisocyanate composition A) to an extent of at least 50 mol%, preferably 60 mol%, more preferably 70 mol%, particularly preferably 80 mol%, and in particular 90 mol%, based in each case on the sum of the oligomeric structures present from the group consisting of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione, and oxadiazinetrione structures.

[0065] According to the invention, it is also possible to use oligomeric polyisocyanates which largely do not have an isocyanurate structure and mainly contain at least one of the above-mentioned uretdione, urethane, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure types. According to a particular embodiment of the invention, the polyisocyanate composition A) consists of 50 mol%, preferably 60 mol%, more preferably 70 mol%, particularly preferably 80 mol%, in particular 90 mol%, in each case based on the sum of the oligomeric structures present from the group consisting of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure in the polyisocyanate composition A), of oligomeric polyisocyanates which have a structure type selected from the group consisting of uretdione, urethane, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure.

[0066] A further embodiment of the invention provides for the use of a low-isocyanurate polyisocyanate composition A) which, based on the sum of the oligomeric structures present from the group consisting of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure in the polyisocyanate composition A), has less than 50 mol%, preferably less than 40 mol%, more preferably less than 30 mol%, particularly preferably less than 20 mol%, 10 mol% or 5 mol% of isocyanurate structures.

[0067] A further embodiment of the invention provides for the use of a polymer composition A) of a single defined oligomeric structure type, wherein the oligomeric structure type is selected from the group consisting of uretdione, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure and this structure type is present to at least 50 mol%, preferably 60 mol%, more preferably 70 mol%, particularly preferably 80 mol%, in particular 90 mol%, based on the sum of the oligomeric structures present from the group consisting of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure in the polyisocyanate composition A).

[0068] The proportions of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure in the polyisocyanate composition A) can be calculated, for example, from the integrals of proton-decoupled 13< C-NMR spectra, since the oligomeric structures mentioned provide characteristic signals, and each relate to the sum of uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures present in the polyisocyanate composition A).

[0069] Regardless of the underlying oligomeric structure type (uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure), the polyisocyanate composition A) to be used in the process according to the invention preferably has an (average) NCO functionality of 1.0 to 6.0, preferably 2.0 to 5.0, preferably 2.3 to 4.5.

[0070] Particularly practical results are achieved when the polyisocyanate composition A) to be used according to the invention has an isocyanate group content of 8.0 to 60.0 wt.%. It has proven particularly practical when the polyisocyanate composition A) according to the invention has an isocyanate group content of 14.0 to 30.0 wt.%, based in each case on the weight of the polyisocyanate composition A).

[0071] Manufacturing processes for oligomeric polyisocyanates with uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure are described, for example, in J. Prakt. Chem. 336 (1994) 185 - 200, in DE-A 1 670 666, DE-A 1 954 093, DE-A 2 414 413, DE-A 2 452 532, DE-A 2 641 380, DE-A 3 700 209, DE-A 3 900 053 and DE-A 3 928 503 or in EP-A 0 336 205, EP-A 0 339 396 and EP-A 0 798 299.

[0072] According to an additional or alternative embodiment of the invention, the polyisocyanate composition A) is defined by containing oligomeric polyisocyanates obtained from monomeric polyisocyanates, regardless of the type of modification reaction used, while maintaining a degree of oligomerization of 5 to 45%, preferably 10 to 40%, particularly preferably 15 to 30%. "Degree of oligomerization" is understood to mean the percentage of the isocyanate groups originally present in the starting mixture that is consumed during the preparation process to form uretdione, urethane, isocyanurate, allophanate, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures.

[0073] Suitable starting compounds for the oligomeric polyisocyanates are any monomeric polyisocyanates accessible in various ways, for example by phosgenation in the liquid or gas phase or by a phosgene-free route, such as thermal urethane cleavage. Particularly good results are achieved when the monomeric polyisocyanates are monomeric diisocyanates. Preferred monomeric diisocyanates are those which have a molecular weight in the range of 140 to 400 g / mol and contain aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups, such as, for example, B. 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,4-diisocyanato-3,3,5-trimethylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, 1,3-Diisocyanato-4-methylcyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorone diisocyanate; IPDI), 1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane (H12MDI), 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane, bis(isocyanatomethyl)norbornane (NBDI), 4,4'-diisocyanato-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanato-3,3',5,5'-tetramethyldicyclohexylmethane, 4,4'-diisocyanato-1,1'-bi(cyclohexyl), 4,4'-Diisocyanato-3,3'-dimethyl-1,1'-bi(cyclohexyl), 4,4'-Diisocyanato-2,2',5,5'-tetra-methyl-1,1'-bi(cyclohexyl), 1,8-Diisocyanato-p-menthane, 1,3-Diisocyanato-adamantane, 1,3-Dimethyl-5,7-diisocyanatoadamantane, 1,3- and 1,4-bis-(isocyanatomethyl)benzene (xylylene diisocyanate; XDI), 1,3- and 1,4-bis(1-isocyanato-1-methylethyl)benzene (TMXDI) and bis(4-(1-isocyanato-1-methylethyl)phenyl) carbonate, 2,4- and 2,6-Diisocyanatotoluene (TDI), 2,4'- and 4,4'-Diisocyanatodiphenylmethane (MDI), 1,5-Diisocyanatonaphthalene and any mixtures of such diisocyanates. Other suitable diisocyanates can be found, for example, in Justus Liebig's Annalen der Chemie, Volume 562 (1949), pp. 75-136.

[0074] Furthermore, in the process according to the invention, classic aliphatic or aromatic isocyanate-end-group-bearing prepolymers, such as, for example, aliphatic or aromatic isocyanate-end-group-bearing polyether, polyester, polycarbonate prepolymers can also be used as mono- and polyisocyanates in the polyisocyanate composition A).

[0075] Suitable monomeric monoisocyanates that can optionally be used in the polyisocyanate composition A) include, for example, n-butyl isocyanate, n-amyl isocyanate, n-hexyl isocyanate, n-heptyl isocyanate, n-octyl isocyanate, undecyl isocyanate, dodecyl isocyanate, tetradecyl isocyanate, cetyl isocyanate, stearyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, 3- or 4-methylcyclohexyl isocyanate, or any mixtures of such monoisocyanates. An example of a monomeric isocyanate with an isocyanate functionality greater than two that can optionally be added to the polyisocyanate composition A) is 4-isocyanatomethyl-1,8-octane diisocyanate (triisocyanatononane; TIN).

[0076] According to one embodiment of the invention, the polyisocyanate composition A) contains at most 25 wt.%, at most 10 wt.%, at most 5 wt.%, or at most 1 wt.%, based in each case on the weight of the polyisocyanate composition A), of aromatic polyisocyanates. As used herein, "aromatic polyisocyanate" means a polyisocyanate having at least one aromatically bound isocyanate group.

[0077] Aromatically bound isocyanate groups are isocyanate groups that are bound to an aromatic hydrocarbon residue.

[0078] According to a preferred embodiment of the process according to the invention, a polyisocyanate composition A) is used which has exclusively aliphatically and / or cycloaliphatically bound isocyanate groups.

[0079] Aliphatically or cycloaliphatically bound isocyanate groups are understood to be isocyanate groups that are bound to an aliphatic or cycloaliphatic hydrocarbon residue.

[0080] According to another preferred embodiment of the process according to the invention, a polyisocyanate composition A) is used which consists of or contains one or more oligomeric polyisocyanates, wherein the one or more oligomeric polyisocyanates have exclusively aliphatically and / or cycloaliphatically bound isocyanate groups.

[0081] According to another preferred embodiment of the process according to the invention, a polyisocyanate composition A) is used which consists of or contains one or more monomeric polyisocyanates, wherein the one or more monomeric polyisocyanates have exclusively aliphatically and / or cycloaliphatically bound isocyanate groups.

[0082] According to a further embodiment of the invention, the polyisocyanate composition A) consists of at least 80, 85, 90, 95, 98, or 99 wt. %, based in each case on the weight of the polyisocyanate composition A), of oligomeric polyisocyanates containing exclusively aliphatically and / or cycloaliphatically bound isocyanate groups. Practical experiments have shown that particularly good results can be achieved with polyisocyanate compositions A) in which the oligomeric polyisocyanates contained therein contain exclusively aliphatically and / or cycloaliphatically bound isocyanate groups.

[0083] According to a particularly preferred embodiment of the process according to the invention, a polyisocyanate composition A) is used which consists of or contains one or more oligomeric polyisocyanates, wherein the one or more oligomeric polyisocyanates are based on 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), isophorone diisocyanate (IPDI) or 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or mixtures thereof.

[0084] The catalytic trimerization of the polyisocyanate composition A) takes place according to the process according to the invention in the presence of a fibrous filler B).

[0085] Suitable fibrous fillers B) are, for example, all inorganic fibers, organic fibers, natural fibers or mixtures thereof known to the person skilled in the art.

[0086] Fibrous fillers are understood to be materials whose aspect ratio, ie the length divided by the diameter, is greater than 5, preferably greater than 20, in particular greater than 50 and particularly preferably greater than 100.

[0087] Examples of inorganic fibers suitable for the invention include glass fibers, basalt fibers, boron fibers, ceramic fibers, whiskers, silica fibers, and metallic reinforcing fibers. Examples of organic fibers suitable for the invention include aramid fibers, carbon fibers, polyester fibers, nylon fibers, and Plexiglas fibers. Examples of natural fibers suitable for the invention include flax fibers, hemp fibers, wood fibers, cellulose fibers, and sisal fibers.

[0088] According to a preferred embodiment of the invention, the individual fibers have a diameter of less than 0.1 mm, preferably less than 0.05 mm, particularly preferably less than 0.02 mm, in particular less than 0.015 mm, very particularly preferably less than 0.01 mm.

[0089] According to a preferred embodiment of the invention, the fibrous filler B) is selected from the group consisting of glass fibers, basalt fibers, carbon fibers and mixtures thereof.

[0090] According to a particularly preferred embodiment of the invention, glass fibers and / or carbon fibers, in particular glass fibers, are used as fibrous fillers.

[0091] According to a preferred embodiment of the invention, the fiber content in the polyisocyanurate composite material is more than 10 wt.%, preferably more than 30 wt.%, particularly preferably more than 50 wt.%, preferably more than 60 wt.%, very particularly preferably more than 70 wt.%, in particular 80, 85, 90 wt.%, based on the polyisocyanurate composite material.

[0092] The polyisocyanurates of the invention are obtainable by catalytic trimerization according to the process of the invention. "Catalytic" means in the presence of a suitable trimerization catalyst C).

[0093] The trimerization catalyst C) contains, as a metal component, an alkaline alkali metal or alkaline earth metal salt, which, as a saturated aqueous solution, has a pH of greater than 7, particularly greater than 8, and especially greater than 9 (measured with litmus paper) at 23 °C, and a polyether. Sodium and potassium salts are particularly preferred. Potassium salts are best used.

[0094] Preferred trimerization catalysts C) comprise carboxylates and alcoholates of these metals as alkali or alkaline earth metal salts. Particularly preferred trimerization catalysts C) comprise alkali or alkaline earth metal salts of aliphatic carboxylic acids having 1 to 20, in particular 1 to 10, carbon atoms, for example metal salts of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, 2-ethylhexanoic acid, enanthic acid, caprylic acid, pelargonic acid, and capric acid. Acetate salts are particularly preferred.

[0095] The trimerization catalyst C) comprises, as a metal component, an element selected from the group consisting of alkali metals and alkaline earth metals. Particularly preferred metal components are sodium and potassium.

[0096] According to a further preferred embodiment, the metal salt is an alkali metal or alkaline earth metal acetate or octoate, most preferably an alkali metal acetate, especially potassium acetate. Tin octoate is also preferred.

[0097] The trimerization catalyst C) additionally comprises a polyether. Preferred polyethers are selected from the group consisting of crown ethers, diethylene glycol, polyethylene glycols, and polypropylene glycols. It has proven particularly practical in the process according to the invention to use a trimerization catalyst C) which comprises, as the polyether, a polyethylene glycol or a crown ether, particularly preferably 18-crown-6 or 15-crown-5. The trimerization catalyst C) can preferably comprise a polyethylene glycol having a number-average molecular weight of 106 to 1000 g / mol, preferably 200 to 1000 g / mol, more preferably 300 to 500 g / mol, and in particular 350 to 450 g / mol. In this application, the term "polyethylene glycol" also refers to diethylene glycol.

[0098] For the purposes of this application, the number-average molecular weight is always determined by gel permeation chromatography (GPC) in tetrahydrofuran at 23°C. The procedure is according to DIN 55672-1: "Gel Permeation Chromatography, Part 1 - Tetrahydrofuran as Eluent" (SECurity GPC system from PSS Polymer Service, flow rate 1.0 ml / min; columns: 2×PSS SDV linear M, 8×300 mm, 5 µm; RID detector). Polystyrene samples of known molecular weight are used for calibration. The calculation of the number-average molecular weight is software-assisted. Baseline points and evaluation limits are defined according to DIN 55672 Part 1.

[0099] The polyethers can also carry additional functionalities, e.g., at the polyether chain ends or within the polyether chain, to ensure better solubility in the polyisocyanate composition A) or a better co-catalytic effect. Such derivatized polyethers also fall under the term "polyether" here.

[0100] Very particularly preferred trimerization catalysts C) for the process according to the invention comprise potassium acetate or potassium octoate as alkali metal salt and polyethylene glycols, in particular potassium acetate and polyethylene glycol having a number-average molecular weight of 400 g / mol, as polyethers.

[0101] The trimerization catalysts C) can be used in the process according to the invention both individually and in the form of any mixtures with one another.

[0102] Along with temperature, the catalyst concentration is an important parameter for the process for producing polyisocyanurate composite materials. If the catalyst concentration in the reactive resin mixture is too low, the overall crosslinking reaction is too slow and the process is inefficient. If the catalyst concentration in the reactive resin mixture is too high, the pot life of the resin mixture—defined as the time period from mixing the polyisocyanate composition A) with the trimerization catalyst C) until the viscosity of the reaction mixture at 23 °C is twice the initial value—is reduced too much, making the process impractical.

[0103] In the process according to the invention, the trimerization catalyst C) is used in a concentration of 0.04 to 15.0 wt.%, preferably 0.10 to 8.0 wt.%, and particularly preferably 0.5 to 5.0 wt.%, based on the amount of polyisocyanate composition A) used. For the purpose of calculating the concentration, only the mixture of the at least one basic compound of the alkali or alkaline earth metals and the at least one polyether is considered as trimerization catalyst C).

[0104] The trimerization catalysts C) used in the process according to the invention are generally sufficiently soluble or dispersible in the polyisocyanate composition A) in the amounts required to initiate the oligomerization reaction. The trimerization catalyst C) is therefore preferably added to the polyisocyanate composition A) in bulk.

[0105] Addition of the trimerization catalyst C) in bulk means that the alkali or alkaline earth metal salt is dissolved or at least suspended in a suitable catalyst solvent, if required. The proportion of metal in this solution can be freely selected within the scope of optimizing the process conditions over a wide range, but for practical reasons is usually less than 50 wt.%, preferably less than 25 wt.%, particularly preferably less than 20 wt.% or less than 15 wt.%, and in particular less than 10 wt.%. However, the proportion is in any case greater than 0.1 wt.%. The above proportions refer to the total weight of metal salt and polyether.

[0106] If necessary, the trimerization catalysts C) can also be used dissolved in a suitable organic solvent to improve their incorporation. The degree of dilution of the catalyst solutions can be freely selected within a very wide range.

[0107] Suitable catalyst solvents are, for example, solvents inert towards isocyanate groups such as hexane, toluene, xylene, chlorobenzene, ethyl acetate, butyl acetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl or ethyl ether acetate, diethylene glycol ethyl and butyl ether acetate, propylene glycol monomethyl ether acetate, 1-methoxypropyl-2-acetate, 3-methoxy-n-butyl acetate, propylene glycol diacetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, lactones such as β-propiolactone, γ-butyrolactone, ε-caprolactone and ε-methylcaprolactone, but also solvents such as N-methylpyrrolidone and N-methylcaprolactam, 1,2-propylene carbonate, methylene chloride, dimethyl sulfoxide, triethyl phosphate or any mixtures of such solvents.

[0108] It has proven particularly advantageous if the alkali or alkaline earth metal salt and the polyether are not added separately to the polyisocyanate and then mixed, but rather if the metal salt is first dissolved in the polyether in a first step and this solution is added to the polyisocyanate composition A) in a second step. Furthermore, it has been found that the alkaline salts, and in particular the alkaline potassium and sodium salts, dissolve better in polyethers based on ethylene oxide compared to polyethers based on propylene oxide.Therefore, it is preferred to add a catalyst solution consisting of at least the metal salt dissolved in polyether to the polyisocyanate composition A), particularly preferred is the addition of a catalyst solution consisting of an alkaline metal salt dissolved in polyethylene glycol to the polyisocyanate composition A), and most preferred is the addition of a catalyst solution consisting of an alkaline potassium salt dissolved in a polyethylene glycol (average molecular weight between 106 and 1000 g / mol) to the polyisocyanate composition A).

[0109] In addition to acting as a solvent for the metal salt, the polyether can also simultaneously contribute to activating and enhancing the catalytic effect. This is particularly true when alkali and alkaline earth metal salts are used. This effect is observed with many polyethers, but is most pronounced for the process according to the invention when polyethers based on ethylene oxide are used. It has proven advantageous if several ethylene oxide units are present in immediate succession in polymerized form. Therefore, preference is given to polyethers which contain at least 3, preferably 5, and most preferably 7 ethylene oxide units in the polymer chain. It is preferred that the polyether contains a maximum of 10 ethylene oxide units in immediate succession, while maintaining the aforementioned minimum lengths.

[0110] The corresponding alkali or alkaline earth metal salt can, in principle, be present in the polyether up to saturation, since increased activation of at least part of the metal salt by the polyether always occurs. For practical reasons, the lower limit of the metal salt concentration is determined by diluting the polyisocyanate mixture with polyether if the metal concentration in the ether is too low. Therefore, a metal ion concentration of the catalytic metal salt in the polyether between 0.01 wt.% and 50 wt.% is preferred, preferably between 0.1 wt.% and 25 wt.%, particularly preferably between 0.5 wt.% and 15 wt.%, and in particular between 1 wt.% and 10 wt.%.

[0111] According to a particularly preferred embodiment of the process according to the invention, the catalyst comprises a polyether having at least 5 consecutive ethylene oxide units in the molecule, in which an alkaline potassium, lithium or sodium salt is dissolved with a metal ion concentration between 0.01 wt.% and 50 wt.%, preferably between 0.1 wt.% and 25 wt.%, particularly preferably between 0.5 wt.% and 15 wt.% and in particular between 1 wt.% and 10 wt.%. Most preferred is a polyether having at least 7 consecutive ethylene oxide units in the molecule, in which an alkaline potassium salt is dissolved with a potassium ion concentration between 0.5 wt.% and 15 wt.%. If polyethers having at least 11 consecutive ethylene oxide units that are no longer liquid at room temperature are used, the use of additional solvents as described below is preferred.

[0112] If catalyst solvents are used in the process according to the invention, catalyst solvents which carry groups reactive towards isocyanates and which can be incorporated into the polyurethane plastic are preferably used. Examples of such solvents are mono- or polyhydric simple alcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, n-hexanol, 2-ethyl-1-hexanol, ethylene glycol, propylene glycol, the isomeric butanediols, 2-ethyl-1,3-hexanediol or glycerol; ether alcohols, such as1-Methoxy-2-propanol, 3-ethyl-3-hydroxymethyloxetane, tetrahydrofurfuryl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monothyl ether, diethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol or also liquid higher molecular weight polyethylene glycols, polypropylene glycols, mixed polyethylene / polypropylene glycols and their monoalkyl ethers; ester alcohols such as ethylene glycol monoacetate, propylene glycol monolaurate, glycerol mono- and diacetate, glycerol monobutyrate or 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate; unsaturated alcohols such as allyl alcohol, 1,1-dimethylallyl alcohol or olein alcohol; araliphatic alcohols such as benzyl alcohol; N-monosubstituted amides such as N-methylformamide, N-methylacetamide, cyanoacetamide or 2-pyrrolidinone or any mixtures of such solvents.

[0113] Since the isocyanurate formation, depending on the catalyst used, is often accompanied by side reactions, for example dimerization to uretdione structures or trimerization to form iminoxadiazinediones (so-called asymmetric trimers) and, in the presence of urethane groups in the starting polyisocyanate, by allophanatization reactions, the term "trimerization" is intended to be synonymous for these additional reactions in the context of the present invention.

[0114] According to a particular embodiment, however, trimerization means that predominantly cyclotrimerizations of at least 50%, preferably at least 60%, particularly preferably at least 70%, in particular at least 80%, and most particularly preferably 90% of the isocyanate groups present in the polyisocyanate composition A) are catalyzed to form isocyanurate structural units. However, side reactions, particularly those to form uretdione, allophanate, and / or iminooxadiazinedione structures, commonly occur and can even be used specifically, for example, to advantageously influence the glass transition temperature (Tg) of the resulting polyisocyanurate plastic.

[0115] The polyisocyanurate composite materials obtainable by the process according to the invention are already distinguished as such, i.e. without the addition of corresponding auxiliaries and additives D), by very good light resistance and weathering resistance. Nevertheless, customary auxiliaries and additives D), such as, for example, customary fillers, UV stabilizers, antioxidants, mold release agents, water scavengers, slip additives, defoamers, leveling agents, rheology additives, flame retardants and / or pigments, can optionally be used in their production. These auxiliaries and additives D), with the exception of fillers and flame retardants, are usually present in the polyisocyanurate composite material in an amount of less than 10 wt. %, preferably less than 5 wt. %, particularly preferably up to 3 wt. %, based on the polyisocyanate composition A). Flame retardants are usually present in amounts of at most 70 wt. %, preferably at most 50 wt.-%, particularly preferably at most 30 wt.%, calculated as the total amount of flame retardants used based on the total weight of the polyisocyanate composition A), in the polyisocyanurate composite material.

[0116] Suitable fillers D w ) are, for example, AlOH 3 , CaCO 3 , silicon dioxide, magnesium carbonate, minerals containing silicates, sulfates, carbonates and the like, such as magnesite, baryte, mica, dolomite, kaolin, clay minerals, metal pigments such as TiO 2 and other known customary fillers. These fillers D w ) are preferably used in amounts of at most 80 wt. %, preferably at most 60 wt. %, particularly preferably at most 40 wt. %, very particularly preferably at most 30 wt. %, in particular at most 20, 10, 5 wt. %, calculated as the total amount of fillers used, based on the total weight of the polyisocyanate composition A).

[0117] Suitable UV stabilizers D x ) can preferably be selected from the group consisting of piperidine derivatives, such as 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-1,2,2,6,6-pentamethylpiperidine, bis-(2,2,6,6-tetra-methyl-4-piperidyl)-sebacate, bis(1,2,2,6,6-pentamethyl-1-4-piperidinyl)-sebacate, bis-(2,2,6,6-tetramethyl-4-piperidyl)-suberate, bis-(2,2,6,6-tetramethyl-4-piperidyl)-dodecanedioate; benzophenone derivatives, such as 2,4-dihydroxy, 2-hydroxy-4-methoxy, 2-hydroxy-4-octoxy, 2-hydroxy-4-dodecyloxy or 2,2'-dihydroxy-4-dodecyloxy-benzophenone; Benztriazole derivatives, such as2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol, 2-(2H-Benzotriazol-2-yl)-6-dodecyl-4-methylphenol, 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(5-Chlor-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2H-Benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, Isooctyl-3-(3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxyphenylpropionat), 2-(2H-Benzotriazol-2-yl)-4,6-bis(1,1-dimethylethyl)phenol, 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(5-Chlor-2H-benzotriazol-2-yl)-4,6-bis(1,1-dimethylethyl)phenol; Oxalaniliden, wie z.B. 2-Ethyl-2'-ethoxy- oder 4-Methyl-4'-methoxyoxalanilid; Salicylsäureestern, wie z.B. Salicylsäurephenylester, Salicylsäure-4-tert-butylphenylester, Salicylsäure-4-tert-octylphenylester; Zimtsäureesterderivaten, wie z.B.Methyl α-cyano-β-methyl-4-methoxycinnamate, butyl α-cyano-β-methyl-4-methoxycinnamate, ethyl α-cyano-β-phenylcinnamate, isooctyl α-cyano-β-phenylcinnamate; and malonic ester derivatives, such as dimethyl 4-methoxybenzylidenemalonate, diethyl 4-methoxybenzylidenemalonate, and dimethyl 4-butoxybenzylidenemalonate. These preferred light stabilizers can be used individually or in any combination.

[0118] Particularly preferred UV stabilizers D x ) for the polyisocyanurate composite materials producible according to the invention are those that completely absorb radiation with a wavelength < 400 nm. These include, for example, the benzotriazole derivatives mentioned. Very particularly preferred UV stabilizers are 2-(5-chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-methylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, and / or 2-(5-chloro-2H-benzotriazol-2-yl)-4,6-bis(1,1-dimethylethyl)phenol.

[0119] If appropriate, one or more of the UV stabilizers D x ) mentioned by way of example are added to the polyisocyanate composition A), preferably in amounts of 0.001 to 3.0% by weight, particularly preferably 0.01 to 2% by weight, calculated as the total amount of UV stabilizers used, based on the total weight of the polyisocyanate composition A).

[0120] Suitable antioxidants D y ) are preferably sterically hindered phenols, which can preferably be selected from the group consisting of vitamin E, 2,6-di-tert-butyl-4-methylphenol (ionol) and derivatives thereof, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triethylene glycol bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, 2,2'-thio-bis(4-methyl-6-tert-butylphenol) and 2,2'-thiodiethyl bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. These can be used individually or in any combination with one another if required.

[0121] These antioxidants D y ) are preferably used in amounts of 0.01 to 3.0 wt.%, particularly preferably 0.02 to 2.0 wt.%, calculated as the total amount of antioxidants used based on the total weight of the polyisocyanate composition A).

[0122] The process according to the invention can be carried out solvent-free, apart from the small amounts of catalyst solvent which may be used.

[0123] Finally, internal mold release agents D z ) can also be added as further auxiliaries and additives D).

[0124] These are preferably non-ionic surfactants containing perfluoroalkyl or polysiloxane units known as mold release agents, quaternary alkylammonium salts, such as trimethylethylammonium chloride, trimethylstearylammonium chloride, dimethylethylcetylammonium chloride, triethyldodecylammonium chloride, trioctylmethylammonium chloride and diethylcyclohexyldodecylammonium chloride, acidic mono- and dialkyl phosphates and trialkyl phosphates with 2 to 18 carbon atoms in the alkyl radical, such asEthyl phosphate, diethyl phosphate, isopropyl phosphate, diisopropyl phosphate, butyl phosphate, dibutyl phosphate, octyl phosphate, dioctyl phosphate, isodecyl phosphate, diisodecyl phosphate, dodecyl phosphate, didodecyl phosphate, tridecanol phosphate, bis(tridecanol) phosphate, stearyl phosphate, distearyl phosphate, waxes such as beeswax, montan wax or polyethylene oligomers, metal salts and esters of oil and fatty acids such as barium stearate, calcium stearate, zinc stearate, glycerol stearate and laurate, esters of aliphatic branched and unbranched alcohols with 4 to 36 carbon atoms in the alkyl radical and any mixtures of such mold release agents.

[0125] Particularly preferred mold release agents D z ) are the fatty acid esters and salts thereof mentioned, as well as acidic mono- and dialkyl phosphates, very particularly preferably those having 8 to 36 carbon atoms in the alkyl radical.

[0126] Internal mold release agents D z ) are optionally used in the process according to the invention preferably in amounts of 0.01 to 15.0 wt.%, particularly preferably 0.02 to 10.0 wt.%, in particular 0.02 to 5.0 wt.%, calculated as the total amount of internal mold release agent used based on the total weight of the polyisocyanate composition A).

[0127] According to one embodiment of the process according to the invention, a trimerization catalyst C) or a mixture of different trimerization catalysts C) is added to the described polyisocyanate composition A), optionally under an inert gas, such as nitrogen, and optionally using the above-mentioned solvents and auxiliaries and additives D), and mixed homogeneously using a suitable mixing unit and added to the fibrous filler B). The addition of catalyst C) and the optionally used solvent and auxiliaries and additives D) can take place in any desired sequence one after the other or as a mixture in the amounts stated above and generally at a temperature of 0 to 100 °C, preferably 15 to 80 °C, particularly preferably 20 to 60 °C. It is also conceivable that first the mixture of polyisocyanate composition A), optionally under an inert gas, such asNitrogen, and optionally with the use of the aforementioned solvents as well as auxiliaries and additives D), a trimerization catalyst C) or a mixture of different trimerization catalysts C) is initially introduced, and then the fibrous filler B) is added. According to a particular embodiment of the invention, the reaction mixture thus obtained has a pot life, as defined above, of greater than 10 minutes, preferably greater than 30 minutes, particularly preferably greater than 60 minutes, in particular greater than 120 minutes. This ensures both reliable miscibility and safe and simple processing and good wetting of the fibers in almost all composite manufacturing processes without the risk of a premature, uncontrolled reaction.

[0128] According to a preferred embodiment of the invention, at least the polyisocyanate composition A), particularly preferably also the mixture of fibrous filler B), catalyst C), and polyisocyanate composition A), are degassed before the reaction using conventional methods. Preferably, the polyisocyanate composition A) according to the invention and / or also the mixture of fibrous filler B), catalyst C), and polyisocyanate composition A) are carefully degassed before the reaction at temperatures between 10 and 100 °C.

[0129] To produce solid bodies, such as components, reaction mixtures containing the catalyst C) and the polyisocyanate composition A) can be filled into open or closed molds which already contain a fibrous filler B), for example by simply pouring them by hand or with the aid of suitable machines, such as the low-pressure or high-pressure machines commonly used in polyurethane technology. The fibrous filler B) can also be added after the reaction mixture comprising catalyst C) and polyisocyanate composition A) has been poured into the mold. Alternatively, the fibrous filler B) and the reaction mixture comprising catalyst C) and polyisocyanate composition A) can be mixed first, and this mixture can be poured into a mold.

[0130] The trimerization reaction can be initiated by heating. The optimal temperature or ambient temperature, depending on the particular catalyst C) selected, is from 80 to 250 °C, preferably from 100 to 230 °C, particularly preferably from 150 to 200 °C. The trimerization can be carried out particularly advantageously at temperatures above the glass transition temperature of the desired products. According to a particular embodiment of the invention, the temperature of the reaction mixture reaches more than 80 °C during the course of the reaction but also remains locally below 350 °C, preferably below 300 °C, particularly preferably <250 °C.

[0131] Depending on the selected trimerization catalyst C), the polyisocyanate composition A), and the selected reaction temperature, the trimerization reaction is largely complete after a period of a few seconds to a few minutes, as defined below. In practice, it has been shown that the trimerization reaction is typically largely complete in less than 30 minutes at reaction temperatures greater than 150°C. According to one embodiment, the catalytic trimerization at a temperature greater than 150°C is largely complete within less than 10 minutes, in particular less than 5 minutes, as defined below.

[0132] When "ambient temperatures" are mentioned here, this means the ambient temperature. According to a preferred embodiment of the invention, the trimerization reaction is largely completed at a reaction temperature of greater than 80°C, preferably 100°C, in particular greater than 120°C, preferably greater than 150°C, particularly preferably greater than 170°C, in less than 10 minutes, particularly preferably less than 5 minutes, very particularly preferably less than 3 minutes, preferably less than 1 minute, in particular less than 45 seconds. According to a further preferred embodiment of the invention, the trimerization reaction is largely completed at a reaction temperature of less than 250°C, in particular less than 230°C, preferably less than 200°C, particularly preferably less than 190°C, in less than 5 minutes, particularly preferably less than 3 minutes, in particular less than 1 minute, very particularly preferably less than 45 seconds.

[0133] These reaction rates are preferably achieved by using salts of alkali or alkaline earth metals in combination with polyethers.

[0134] For the purposes of the present invention, a trimerization reaction to form polyisocyanurate structures can be considered "largely completed" when at least 80%, preferably at least 90%, particularly preferably at least 95%, and in particular at least 98%, most preferably 99%, of the free isocyanate groups originally present in the polyisocyanate composition A) have reacted. In other words, the polyisocyanurate composite material obtained by the process according to the invention preferably still contains only at most 20%, at most 10%, particularly preferably at most 5%, in particular at most 2%, most preferably at most 1%, of the isocyanate groups originally present in the polyisocyanate composition A).

[0135] The course of the reaction can initially be determined by titrimetric determination of the NCO content. However, as the reaction progresses, gelation and solidification of the reaction mixture rapidly begin, making wet chemical analysis impossible. The further conversion of the isocyanate groups can then only be monitored by spectroscopic methods, for example, IR spectroscopy based on the intensity of the isocyanate band at approximately 2270 cm -1.

[0136] The invention also relates to the polyisocyanurate composite material obtainable by the process according to the invention. The polyisocyanurate composite material obtainable by the process according to the invention is preferably one which comprises highly converted polyisocyanurates as the polymeric matrix material, i.e., those in which the trimerization reaction to form polyisocyanurate structures is largely complete. For the purposes of the present invention, a trimerization reaction to form polyisocyanurate structures can be regarded as "largely complete" if at least 80%, preferably at least 90%, particularly preferably at least 95%, and in particular at least 98%, very particularly preferably 99%, of the free isocyanate groups originally present in the polyisocyanate composition A) have reacted.In other words, in the polyisocyanurate composite material obtained by the process according to the invention, preferably only a maximum of 20%, a maximum of 10%, particularly preferably a maximum of 5%, in particular a maximum of 2%, very particularly preferably a maximum of 1% of the isocyanate groups originally contained in the polyisocyanate composition A) are still present. This can be achieved by carrying out the catalytic trimerization in the process according to the invention at least up to a degree of conversion at which, for example, only a maximum of 20% of the isocyanate groups originally contained in the polyisocyanate composition A) are still present, so that a highly converted polyisocyanurate is obtained. The percentage of isocyanate groups still present can be determined by comparing the content of isocyanate groups in wt. % in the original polyisocyanate composition A) with the content of isocyanate groups in wt.-% in the reaction product, for example by comparing the intensity of the isocyanate band at approx. 2270 cm -1< using IR spectroscopy.

[0137] According to a preferred embodiment, the total content of extractable isocyanate-containing compounds in the polyisocyanurate composite material according to the invention, based on the polyisocyanate composition A) used, is less than 1 wt.%. The total content of extractable isocyanate-containing compounds can be determined particularly practically by conventional methods, preferably by extraction with suitable solvents inert toward isocyanate groups, for example, aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane, cyclohexane, toluene, or xylene, followed by determination of the isocyanate group content in the extract, for example, by IR spectroscopy.

[0138] According to another preferred embodiment, the non-additized polyisocyanurate composite materials according to the invention have a b* value determined according to DIN 5033 in the L*a*b* color space of less than 8, particularly preferably less than 7, and especially less than 6.5. "Non-additized" in this context means that the polyisocyanurate composite material contains no pigments or has not been colored by adding pigments. Each color in the L*a*b* color space is defined by a color locus with the Cartesian coordinates {L*, a*, b*}. The L* axis describes the brightness (luminance) of the color with values from 0 to 100. The a* axis describes the green or red component of a color, with negative values representing green and positive values representing red. The b* axis describes the blue or yellow component of a color, with negative values representing blue and positive values representing yellow.Higher positive b* values therefore indicate strong yellowing, which is undesirable for many applications.

[0139] According to a further preferred embodiment, the polyisocyanurate composite materials according to the invention have a b-value that is at least 5%, preferably 10%, particularly preferably 15% and in particular 25% smaller than samples produced under the same conditions with the same material composition but without fibrous filler B).

[0140] According to a further preferred embodiment, the polyisocyanurate composite materials according to the invention have a b-value which is at least 0.35, preferably 0.5, particularly preferably 0.75, very particularly preferably 1 and in particular 2 units smaller compared to samples which were produced under the same conditions with the same material composition but without fibres.

[0141] The process according to the invention allows for the very efficient production of homogeneous, bubble-free polyisocyanurate composite materials. The bubble-free nature of a polyisocyanurate composite material can be specified by its density. First, the average density of the polyisocyanurate composite material is determined. Then, the density of the fiber material is determined (if not already known). Using these two values, the density of the matrix material can also be calculated. The polyisocyanurate composite materials according to the invention are characterized in particular by a density of the polyisocyanurate resin matrix of greater than 1.00 g / cm³, determined according to DIN EN ISO 1183-1.

[0142] The process according to the invention provides in particular polyisocyanurate composite materials with an average density of greater than 1.30 g / cm 3< , preferably greater than 1.5 g / cm 3< and particularly preferably greater than 1.7 g / cm 3< .

[0143] The polyisocyanurate composite materials obtainable by the process according to the invention contain, depending on the type of polyisocyanate composition A) used, in addition to isocyanurate structures and optionally further oligomeric structures and are characterized by excellent heat and weather resistance.

[0144] Weather resistance can be assessed, for example, using accelerated weathering tests. In this test, the sample is exposed to defined amounts and times of UVA and UVB radiation, heat, and moisture according to the selected standard.

[0145] The process according to the invention produces, in particular, polyisocyanurate composite materials that, when exposed to weathering with a Ci 5000 or Ci 4000 device from Atlas Material Testing Technology according to the SAE J 2527 standard, exhibit no significant changes in the sample after 500 hours, preferably after 1000 hours, particularly preferably after 2000 hours, and especially after 4000 hours. For example, the b-value of the color scale described above increases by a maximum of 20, preferably by a maximum of 15, particularly preferably by a maximum of 10, and especially by a maximum of 5 units after 1000 hours of testing according to SAE J 2527.

[0146] The amount of nitrogen in the polyisocyanurate plastic matrix of the finished polyisocyanurate composite material is preferably at least 9 wt.%, more preferably at least 13 wt.%, most preferably 15 wt.%, based on the total weight of the polyisocyanurate plastic matrix in the polyisocyanurate composite material. The amount of nitrogen in the finished polyisocyanurate plastic can be determined by elemental analysis, e.g., using a vario EL cube device from elementar Americas Inc.

[0147] In embodiments in which alkali or alkaline earth metal salts are used as catalysts, the weight fraction of the metal or metal ions in the polyisocyanurate composite material is at least 0.00025 wt. %, particularly preferably at least 0.001 wt. %, and very particularly preferably at least 0.01 wt. %, based on the polyisocyanate composition A). The weight fraction of metal ions in the finished polyisocyanurate material can be determined by atomic absorption spectroscopy or atomic emission spectroscopy. In such embodiments, the weight fraction of potassium and sodium ions, in particular potassium ions, in the polyisocyanurate composite material is preferably 0.00025 to 3 wt. %, preferably 0.001 to 1 wt. %, and particularly preferably 0.01 to 0.5 wt. %, based on the polyisocyanurate composite material.

[0148] In embodiments in which alkali or alkaline earth metal salts are used as catalysts, the weight fraction of the metal or metal ions in the polyisocyanurate plastic or in the polyisocyanurate composition A is at least 0.0008 wt.%, particularly preferably at least 0.003 wt.%, and very particularly preferably at least 0.03 wt.%, based on the polyisocyanate composition A). The weight fraction of metal ions in the finished polyisocyanurate material can be determined by atomic absorption spectroscopy or atomic emission spectroscopy. In such embodiments, the weight fraction of potassium and sodium ions, in particular potassium ions, in the polyisocyanurate composite material is preferably 0.0008 to 3 wt.%, preferably from 0.003 to 1 wt.%, and particularly preferably from 0.03 to 0.5 wt.%, based on the polyisocyanate composition A).

[0149] The process according to the invention makes it possible to efficiently produce weather-resistant, bubble-free polyisocyanurate composite materials in a simple manner by suitable selection of starting polyisocyanates at high temperatures and short reaction times.

[0150] In contrast to polyisocyanurate composite materials produced by prior art processes, the products of the invention are characterized by different chemical and physical properties. The different physical properties (e.g., density, color number) compared to prior art polyisocyanurate composite materials could be attributed to a novel network structure in the polyisocyanurate composite material resulting from the process according to the invention. The different chemical properties (minimum concentration of metal ions and / or minimum concentration of nitrogen in the polyisocyanurate matrix) compared to polyisocyanurate composite materials may be due to the retention of the alkali or alkaline earth metal salt catalyst in the product or to the proportion of isocyanurate groups in the finished polyisocyanurate material.

[0151] Compared to polyisocyanurate plastics produced by conventional processes, the process products according to the invention are characterized by the fact that they allow the problem-free production of solid, large-volume components without extreme local overheating, which usually leads to inhomogeneities and side reactions, and thus to discoloration and bubbles, starting from oligomeric polyisocyanates in short, efficient and occupationally hygienically advantageous processes.

[0152] The invention further relates to the use of the polyisocyanurate composite material for producing components and components containing the polyisocyanurate composite material according to the invention.

[0153] When reference is made here to "components", this refers in particular to structural components such as profiles, beams, reinforcing struts and reinforced lightweight components, such as sporting goods (arrows, bows, skis, rackets, etc.), manhole covers, panels, housings, leaf springs, trunk or engine compartment covers, bumpers, panels, aprons as well as pipes, pressure vessels and tanks.

[0154] Components manufactured with the polyisocyanurate composite material do not require an additional coating step for many applications. Light colors such as white or yellow can be achieved directly by adding pigments to the reactive resin solution without discoloration. The high UV and weathering resistance of the components eliminates the need for protective coatings, for example, in outdoor applications. This saves costs. Furthermore, repair work required when such a protective layer is damaged or flaking due to external influences is eliminated. This prevents the associated unsightly appearance and weathering of the substrate. This further saves costs over the component's life cycle and contributes to the ecological sustainability of the use of such components.

[0155] The invention is explained in more detail below using examples. General Information:

[0156] Unless otherwise stated, all percentages are by weight (wt%).

[0157] The ambient temperature of 25 °C prevailing at the time of the experiment is referred to as RT (room temperature).

[0158] The NCO functionality of the various raw materials was determined mathematically or taken from the respective data sheet of the raw material. Measurement methods:

[0159] The methods listed below for determining the corresponding parameters were used to carry out and evaluate the examples and are also the methods for determining the parameters relevant to the invention in general. Determination of yellowing using Cie-Lab measurement

[0160] After curing and cooling, the composite material was removed from the mold, and the measurement was performed on the lower, smooth surface of the material. A colorimeter from BYK-Gardner GmbH, type color-guide sphere spin with a CIE L*a*b scale, measuring geometry d / 8°, and illuminant / observer D65 / 10°, was used. The value used corresponds to the arithmetic mean of five measurements. Determination of the Tg value using DSC

[0161] The glass transition temperature T g was determined by DSC (differential scanning calorimetry) with a Mettler DSC 12E (Mettler Toledo GmbH, Gießen, Germany) in accordance with DIN EN 61006. Calibration was performed using the melting onset temperature of indium and lead. 10 mg of substance were weighed into standard capsules. The measurement was performed by heating three times from -50 °C to +200 °C at a heating rate of 20 K / min, followed by cooling at a rate of 320 K / min. Cooling was performed using liquid nitrogen. Nitrogen was used as the purge gas. The values given in the table below are each based on the evaluation of the first heating curve, since changes in the sample during the measurement process at high temperatures are possible for the reactive systems investigated due to the temperature stress in the DSC. The glass transition temperature T g was determined as the temperature at half the height of a glass transition step. Determination of Shore hardness

[0162] Shore hardness was measured according to DIN 53505 using a Zwick 3100 Shore hardness tester (Zwick, Germany) at 23 °C and 50% humidity. Determination of weather resistance

[0163] The weathering tests were conducted in a Ci5000 from Atlas Material Testing Technology. The samples were placed in the device with the smooth side facing the xenon lamp, and the cycles were run according to SAE J 2527. Visual inspections were performed at specific intervals for cracks, surface gloss and smoothness, appearance, and color change. For comparison, a second sample was prepared at the same time, but not weathered. Instead, it was stored in the dark at room temperature and 40 to 70% relative humidity, and used as a reference. Determination of pot life

[0164] The viscosity of a small amount of the reactive resin material, including the added catalyst, was measured at 23 °C using an Anton Paar Physica MCR 51 (plate / plate; shear rate 1s -1< ). The pot life was the time required for the sample's viscosity to double. Experimental determination of the nitrogen content of the plastic matrix in the finished polyisocyanurate composite material

[0165] A few milligrams of the plastic matrix are carefully scraped from the polyisocyanurate composite material. A portion of this is combusted in the TGA under air (1000 °C), and the non-combustible solids (fiber, inorganic fillers) are determined as a residue. The nitrogen content is then determined using another portion of the sample in a vario EL Cube from elementar Americas Inc. The nitrogen content in the matrix can be calculated from the difference. Calculation of the nitrogen content of the plastic matrix in the finished polyisocyanurate composite material

[0166] The nitrogen content is determined as the sum of all nitrogen atoms present in the plastic matrix from organic materials, i.e. from isocyanate groups, organic additives with amino groups, aromatic heterocycles with nitrogen functionalities, etc., divided by the total amount of organic components multiplied by 100%. Input materials

[0167] Desmodur N 3600 is an HDI trimer (NCO functionality >3) with an NCO content of 23.0 wt.% from Covestro AG. Its viscosity is approximately 1200 mPas at 23°C (DIN EN ISO 3219 / A.3).

[0168] Desmodur H is an HDI monomer (NCO functionality 2) with an NCO content of 49.7 wt.% from Covestro AG. Its viscosity is approximately 3 mPas at 23 °C (DIN EN ISO 3219 / A.3).

[0169] Desmodur ECO N 7300 is a PDI trimer (NCO functionality >3) with an NCO content of 21.5 wt.% from Covestro AG. Its viscosity is approximately 9500 mPas at 23 °C (DIN EN ISO 3219 / A.3).

[0170] Desmodur I is an IPDI monomer (NCO functionality 2) with an NCO content of 37.5 wt.% from Covestro AG. Its viscosity is approximately 10 mPas at 23 °C (DIN EN ISO 3219 / A.3).

[0171] Desmodur W is a H12MDI monomer (NCO functionality 2) with an NCO content of 31.8 wt.% from Covestro AG. Its viscosity is approximately 30 mPas at 23 °C (DIN EN ISO 3219 / A.3).

[0172] Polyethylene glycol 400 was purchased from ACROS with a purity of > 99 wt.%.

[0173] Triethylene glycol with a purity of > 99 wt.% was purchased from ACROS.

[0174] Potassium acetate with a purity of > 99 wt.% was purchased from ACROS.

[0175] The short glass fiber, designated 910A-10P, was supplied by Owens Corning and was available in bundles approximately 4.5 mm long. The diameter of the individual fibers was 0.01 mm.

[0176] All raw materials except the catalyst were degassed in vacuum before use, and the polyols were additionally dried. Production of the catalyst

[0177] Potassium acetate (5.0 g) was stirred in PEG 400 (95.0 g) at room temperature until completely dissolved. A 5 wt% solution of potassium acetate in PEG 400 was obtained and used as a catalyst without further treatment. Production of polyisocyanurate composites

[0178] Unless otherwise stated, to produce the polyisocyanurate composites, the isocyanate composition was first prepared by mixing the corresponding isocyanate components at 25 °C in a Hauschild DAC 150.1 FVZ speed mixer for 60 to 300 seconds at 2750 rpm. This was then mixed with the catalyst at room temperature (speed mixer). Subsequently, one-tenth of the glass fiber quantity was added. The entire mass was mixed in a Hauschild DAC 150.1 FVZ speed mixer for 60 to 300 seconds at 2750 rpm, during which the short glass fiber bundles exfoliated and everything formed a pasty mass. The remaining glass fiber quantity was then added, and the mass was mixed again in the speed mixer for approximately 60 seconds at 2750 rpm.

[0179] The mixture was then transferred to a mold (metal lid, approximately 6 cm in diameter and approximately 1 cm high) and cured in an oven. The following heating program was used: 30 minutes at 180 °C in the presence of Desmodur I or W, and 30 minutes at 160 °C in all other cases. Inventive examples for the production of polyisocyanurate composite materials Example 1

[0180] As described above, Desmodur N 3600 (40.0 g) was mixed with catalyst (0.80 g), the short glass fiber (20.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was 6.71. The pot life was more than 5 hours. In the weathering test, no changes in the surface or color were observed during visual inspection after 1000 hours. Example 2

[0181] As described above, a mixture of Desmodur N 3600 (36.0 g) and Desmodur H (4.0 g) was mixed with catalyst (0.80 g), the short glass fiber (30.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was 6.39. Example 3

[0182] As described above, a mixture of Desmodur N 3600 (36.0 g) and Desmodur H (4.0 g) was mixed with catalyst (0.80 g), the short glass fiber (20.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was 6.77. The pot life was more than 5 hours. In the weathering test, no changes in the surface or color were observed during visual inspection after 1000 hours. The Tg was 117 °C. Example 4

[0183] As described above, Desmodur N 3600 (40.0 g) was mixed with catalyst (0.80 g), the short glass fiber (30.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was 6.40. The pot life was more than 5 hours. Example 5

[0184] As described above, a mixture of Desmodur N 3600 (30.0 g) and Desmodur ECO N 7300 (10.0 g) was mixed with catalyst (0.80 g), the short glass fiber (20.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was 7.89. The pot life was more than 5 hours. In the weathering test, no changes in the surface or color were observed during visual inspection after 1000 hours. Example 6

[0185] As described above, a mixture of Desmodur N 3600 (20.0 g) and Desmodur ECO N 7300 (20.0 g) was mixed with catalyst (0.80 g), the short glass fiber (20.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was 7.60. The pot life was more than 5 hours. The Tg was 124 °C. Example 7

[0186] As described above, a mixture of Desmodur H (5.0 g) and Desmodur ECO N 7300 (45.0 g) was mixed with catalyst (1.00 g), the short glass fiber (25.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was 7.4. The pot life was more than 180 minutes. In the weathering test, no changes in the surface or color were observed during visual inspection after 9,000 hours. Example 8

[0187] As described above, a mixture of Desmodur N 3600 (32.0 g) and Desmodur W (8.0 g) was mixed with catalyst (0.80 g), the short glass fiber (40.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was less than 7. Example 9

[0188] As described above, a mixture of Desmodur N 3600 (32.0 g) and Desmodur I (8.0 g) was mixed with catalyst (0.80 g), the short glass fiber (40.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was less than 7. Non-inventive examples for the preparation of polyisocyanurate composite materials Comparison example 1

[0189] As described above, a mixture of Desmodur N 3600 (36.0 g) and Desmodur H (4.0 g) was mixed with catalyst (0.012 g), the short glass fiber (20.0 g) was incorporated, and the mixture was pressed into the mold. The mixture was placed in an oven at 160 °C for 30 minutes. After this time, the mixture was still sticky and not hard, meaning the crosslinking reaction was incomplete. The material was not analyzed further.

[0190] Comparative Example 1 shows that the catalyst concentration below or equal to an amount of 0.03 wt.% is not sufficient to obtain a fully crosslinked polyisocyanurate plastic in a short time. Comparison example 2

[0191] As described above, a mixture of Desmodur N 3600 (30.0 g) and Desmodur H (10.0 g) was mixed with catalyst (0.80 g), the short glass fiber (20.0 g) was incorporated, and the mixture was pressed into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b-value was 8.27. The pot life was more than 5 hours.

[0192] Comparative Example 2 shows that at a monomer content of over 20 wt.%, the measured b-value increases significantly, which means that the color appearance of the component deteriorates and undesirable side reactions occur. Non-inventive examples of polyisocyanurate materials without fibrous filler

[0193] Unless otherwise stated, the fiber-free polyisocyanurate materials were prepared by first mixing the polyisocyanate composition by blending the corresponding isocyanate components at 25 °C in a Hauschild DAC 150.1 FVZ speed mixer for 60–300 seconds at 2750 rpm. This mixture was then mixed with the catalyst at room temperature (RT) (speed mixer). The mixture was then transferred to a mold (metal lid, approximately 6 cm in diameter and approximately 1 cm high) and cured in an oven. The following heating program was used: 30 minutes at 180 °C in the presence of Desmodur I or W, and 30 minutes at 160 °C in all other cases. Comparison example 3

[0194] As described above, a mixture of Desmodur N 3600 (36.0 g) and Desmodur H (4.0 g) with catalyst (0.80 g) was mixed and poured into the mold. After curing, the block was removed from the mold and its smooth back surface was measured with a colorimeter. The measured b* value was 9.16. Comparison example 4

[0195] As described above, a mixture of Desmodur N 3600 (30.0 g) and Desmodur H (10.0 g) with catalyst (0.80 g) was mixed and the mixture poured into the mold. After curing, the block was removed from the mold and the smooth back surface was measured with a colorimeter. The measured b* value was 9.44. Comparison example 5

[0196] As described above, a mixture of Desmodur N 3600 (30.0 g) and Desmodur ECO N 7300 (10.0 g) with catalyst (0.80 g) was mixed and poured into the mold. After curing, the block was removed from the mold and the smooth back surface was measured with a colorimeter. The measured b* value was 9.80. The pot life was more than 180 minutes. Comparison example 6

[0197] As described above, a mixture of Desmodur N 3600 (20.0 g) and Desmodur ECO N 7300 (20.0 g) with catalyst (0.80 g) was mixed and poured into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b* value was 11.72. The pot life was more than 180 minutes. Comparison example 7

[0198] As described above, Desmodur H (20.0 g) was mixed with catalyst (0.80 g) and the mass poured into the mold. Upon heating, the reaction was vigorous and highly exothermic, producing smoke. The product obtained was a bubbly, brown to dark brown, porous material, which was not further analyzed. Comparison example 8

[0199] As described above, a mixture of Desmodur N 3600 (30.0 g) and Desmodur W (10.0 g) with catalyst (0.80 g) was mixed and poured into the mold. After curing, the block was removed from the mold and its smooth back surface was measured with a colorimeter. The measured b* value was 13.3. Comparison example 9

[0200] As described above, a mixture of Desmodur N 3600 (30.0 g) and Desmodur I (10.0 g) with catalyst (0.80 g) was mixed and the mixture poured into the mold. After curing, the block was removed from the mold and the smooth back side was measured with a colorimeter. The measured b* value was 19.

[0201] The experiments show that the inventive polyisocyanurate composite materials of working examples 1 to 7 exhibit significantly less discoloration (a lower yellowness index or b-value) than the fiber-free polyisocyanurate materials. This means that the fully reacted polyisocyanurate matrix material of the inventive polyisocyanurate composite materials was significantly less damaged or not damaged at all under the drastic reaction conditions compared to the fiber-free polyisocyanurate material. Furthermore, the reactive resin mixtures with the catalyst concentrations used here exhibited pot lives of more than 30 minutes combined with rapid crosslinking times, which is very similar to a one-component system and allows for very easy practical handling. Complex and expensive dosing devices, as required for two-component systems, can therefore be dispensed with.This should pave the way for the efficient use of pure, fiber-reinforced polyisocyanurate composite materials in industry.

Claims

1. Process for producing a composite polyisocyanurate material, comprising the following steps: a) providing a polyisocyanate composition A) which comprises oligomeric polyisocyanates and is low in monomeric diisocyanates, "low in monomeric diisocyanates" meaning that the polyisocyanate composition A) has a content of monomeric diisocyanates of not more than 20% by weight, and consists to an extent of at least 70% by weight of its weight of oligomeric polyisocyanates having exclusively aliphatically or cycloaliphatically bonded isocyanate groups, and b) catalytically trimerizing the polyisocyanate composition A) in the presence of at least one fibrous filler B) and of a trimerization catalyst C) to give the composite polyisocyanurate material, wherein the trimerization catalyst C) is present in a concentration of 0.04% to 15.0% by weight, based on the amount of the polyisocyanate composition A, and wherein the trimerization catalyst C) is an alkaline alkali metal salt or alkaline earth metal salt which, as a saturated aqueous solution, has a pH of greater than 7 at 23°C, and contains a polyether; and wherein the concentration is calculated in respect of trimerization catalyst C) by considering merely the mixture of the at least one alkali metal or alkaline earth metal and the at least one polyether.

2. Process according to Claim 1, characterized in that the trimerization catalyst C) as metal salt in step b) comprises an alkali metal salt or alkaline earth metal salt of a carboxylic acid.

3. Process according to Claim 1 or 2, characterized in that the trimerization catalyst C) as metal salt in step b) comprises potassium acetate.

4. Process according to any of Claims 1 to 3, characterized in that the trimerization catalyst C) comprises a polyethylene glycol.

5. Process according to any of Claims 1 to 4, characterized in that the fibrous filler is selected from the group consisting of glass fibres, basalt fibres, carbon fibres and mixtures thereof.

6. Process according to any of Claims 1 to 5, characterized in that the fibrous filler used is glass fibres.

7. Process according to any of Claims 1 to 6, characterized in that the polyisocyanate composition A) consists to an extent of at least 90% by weight, based in each case on the weight of the polyisocyanate composition A), of oligomeric polyisocyanates.

8. Process according to any of Claims 1 to 7, characterized in that the oligomeric polyisocyanates consist of one or more oligomeric polyisocyanates which are composed of 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, isophorone diisocyanate or 4,4'-diisocyanatodicyclohexylmethane or mixtures thereof.

9. Process according to any of Claims 1 to 8, characterized in that the polyisocyanate composition A) has a mean NCO functionality of 2.0 to 5.0.

10. Process according to any of Claims 1 to 9, characterized in that the catalytic trimerization is conducted at a temperature of greater than 150°C within less than 10 minutes, at least up to a conversion level at which only at most 20% of the isocyanate groups originally present in the polyisocyanate composition A) are still present.

11. Process according to Claim 10, characterized in that the conversion level is a conversion level at which only at most 10% of the isocyanate groups originally present in the polyisocyanate composition A) are still present.

12. Composite polyisocyanurate material obtainable by a process according to any of Claims 1 to 11.

13. Composite polyisocyanurate material according to Claim 12, characterized in that the amount of nitrogen in the finished composite polyisocyanurate material is at least 9% by weight, based on the total weight of the polyisocyanurate plastic matrix in the composite polyisocyanurate material.

14. Composite polyisocyanurate material according to Claim 12 or 13, characterized in that the proportion by weight of the metal or the metal ions in the composite polyisocyanurate material is at least 0.00025% by weight, based on the polyisocyanate composition A).

15. Composite polyisocyanurate material according to any of Claims 12 to 14, characterized in that the composite polyisocyanurate material has a density of greater than 1.30 g / cm3 determined according to DIN EN ISO 1183-1.

16. Use of the composite polyisocyanurate material according to any of Claims 12 to 15 for production of components.

17. Components consisting of or comprising a composite polyisocyanurate material according to any of Claims 12 to 16.