Polyurethane reactive systems for pultrusion

Abstract

This invention relates to a polyurethane reactive system for producing pultruded parts containing reinforcing fibers and its uses.

Description

[0001] This invention relates to a polyurethane reactive system for producing pultruded parts with reinforcing fibers and its uses.

[0002] Pultrusion, also known as strip pultrusion, is a continuous process for producing fiber-reinforced profiles with uniform cross-sections. A pultrusion apparatus typically consists of an impregnation unit, a heated die, and a traction device to keep the process running. Fiber impregnation occurs in an open bath or a closed injection chamber. For thermosetting reactive resins, such as polyurethane, a closed injection chamber is preferred. The injection chamber can be positioned as a separate unit upstream of the actual die or integrated into the die (“direct injection”). The composite material is then formed and cured in the heated die. The finished profile is pulled from the die using the traction device and finally cut to the desired length.

[0003] To maximize the efficiency of pultrusion, a combination of high process speed and excellent mechanical properties and surface quality of pultruded parts is sought. Low traction force (<3kN) is particularly important in liquid processes. Different patents offer various solutions for efficient pultrusion processes of PU resins.

[0004] US2008 / 090966 A1 discloses a reaction system for producing fiber-reinforced composite materials by pultrusion, the system comprising a continuous fiber reinforcement and an immiscible polyurethane formulation, the polyurethane formulation containing a polyisocyanate component comprising at least one polyisocyanate and an isocyanate reactive component comprising at least one isocyanate reactive compound. It is described herein that incompatibility of the polyether polyol used in the isocyanate reactive compound and / or incompatibility between the isocyanate reactive compound and the isocyanate can enable an improved pultrusion process.

[0005] A common practice is to add insoluble solids as additives to isocyanate reactive components to achieve specific functions that single-phase isocyanate reactive components cannot achieve in the same way. These are therefore multiphase isocyanate reactive components. Here, multiphase is defined as having more than one phase present at room temperature over a period of 6 months. For example, solids used for reaction control include water binders (e.g., WO 2011 / 067246 A1, EP2018 / 059790), fillers such as chalk, quartz sand, and gypsum (EP3380539 A1), or encapsulated catalysts (WO 2018 / 162519 A1). In addition to the liquid / solid multiphase characteristics listed, liquid / liquid multiphase characteristics, similar to those observed in oil / water mixtures, are also frequently present. Various publications even describe this phase instability as necessary to achieve low traction (e.g., US 2008 / 090966 A1).

[0006] In addition to the advantages mentioned above, multiphase solid / liquid and / or liquid / liquid systems also have the following disadvantages. Therefore, for example, the logistics of filling and transporting multiphase isocyanate reactive components present significant challenges because, despite the multiphase nature, a homogeneous mixture must be ensured. Constant and adequate mixing must also be ensured in the pultrusion unit to maintain the same composition and thus profile quality throughout the pultrusion process. In particular, filters installed in the metering unit to separate impurities, for example, from the impregnating resin can become clogged by the solid portion of the formulation, thus causing process interruptions. The pumps used are also sensitive to the amount of solids.

[0007] Therefore, the object of the present invention is to develop a pultrusion process that at least partially overcomes the disadvantages of known methods, such as the multiphase nature of the isocyanate reactive component and / or the only partially satisfactory mechanical properties of the resulting pultruded parts, without unduly compromising the efficiency of the method. Furthermore, the transfer of the reactive system to the pultrusion apparatus should be improved, for example, by preventing the pumps and filters from being exposed to solids, and the processability of the reactive system should be simplified. Surprisingly, this object can be achieved by the method according to the invention, so that polyurethane pultruded parts according to the invention can be obtained by using the polyurethane reactive system according to the invention.

[0008] The subject of this invention is a polyurethane reactive system, which comprises

[0009] Isocyanate component A),

[0010] Isocyanate reactive component B), which contains

[0011] 3-13% by weight of polyether polyol B1 with a hydroxyl value (OHZ) of 20 to 50 mg KOH / g, which can be obtained by reacting a first H-functional initiator compound with a functionality f of ≥2 to ≤4 with ethylene oxide and propylene oxide.

[0012] 15-37% by weight of polyether polyol B2 with a hydroxyl value (OHZ) of 900-1100 mg KOH / g, which can be obtained by reacting a second H-functional initiator compound with a functionality f of ≥2 to ≤4 with a second epoxide.

[0013] 50-72% by weight of polyether polyol B3 with a hydroxyl value (OHZ) of >50 to <900 mg KOH / g, which can be obtained by reacting a third H-functional initiator compound with a third epoxide.

[0014] One or more catalysts (B4) and

[0015] Desiccant B5),

[0016] The sum of the weight percentages of components B1) and B2) based on the sum of the amounts of B), C), and D) is ≤40% by weight, and the sum of the weight percentages of components B1), B2), B3), B4), and B5) based on the sum of the amounts of B), C), and D) is ≥90% by weight.

[0017] Internal release agent C),

[0018] And optionally, other auxiliaries and additives (D),

[0019] The total weight percentage of components B), C), and optional D) is 100% by weight.

[0020] Furthermore, the hydroxyl values ​​(OHZ) of the polyether polyols B1), B2) and B3) were determined using ISO 14900.

[0021] In one embodiment of the invention, the amounts of components A), B), C) and optional D) are such that the ratio of the number of NCO groups in (A) to the sum of the number of isocyanate reactive groups in (B), (C) and (D) multiplied by 100 (the so-called index or characteristic value) has a value of 100-150.

[0022] The isocyanate reactive component in this application is a component containing a compound capable of reacting with an isocyanate group, such as a hydroxyl (-OH), an amino (-NH2 or -NRH, where R is an organic residue), or a thio (-SH) group.

[0023] The hydroxyl value (OHZ) in this application is equivalent to the amount of potassium hydroxide in milligrams of acetic acid bound in the acetylation of 1 gram of the substance. For the purposes of this application, OHZ is determined according to ISO 14900.

[0024] The polyisocyanate component A) preferably includes at least one of the monomer methylene di(phenylisocyanate) (MDI), oligomeric MDI, polymeric MDI and mixtures thereof.

[0025] The NCO content of polyisocyanate component A) is preferably greater than 25% by weight, more preferably greater than 30% by weight, and particularly preferably greater than 31.5% by weight. Polyisocyanate component A) preferably has a functionality of 2.1 to 2.9. The viscosity of polyisocyanate component A, as measured according to DIN 53019-1, is preferably ≤500 mPas (at 25°C).

[0026] Alternatively, conventional aliphatic, alicyclic, aryliphatic di- and / or polyisocyanates can be used, especially aromatic isocyanates known in polyurethane chemistry. Examples of suitable polyisocyanates of this kind are ethylene diisocyanate, 1,4-butanediisocyanate, 1,5-pentanediisocyanate, 1,6-hexanediisocyanate (HDI), 1,12-dodecanediisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and mixtures of these isomers, isophorone diisocyanate (IPDI), 2,4- and 2,6-hexahydrotoluene diisocyanate and mixtures of these isomers, 2,2,4- and / or 2,4,4-trimethylhexanediisocyanate, bis(4,4′-, 2,4′- and 2,2′-isocyanate-cyclohexyl)methane or mixtures of these isomers, and aromatic isocyanates of the general formula R(NCO)z, wherein R is a polyvalent organic group containing an aryl group and z is an integer of at least 2. Examples include 1,3-o-xylene diisocyanate, 1,3-p-xylene diisocyanate, 1,3-m-xylene diisocyanate, 2,4-diisocyanate-1-chlorobenzene, 2,4-diisocyanate-1-nitrobenzene, 2,5-diisocyanate-1-nitrobenzene, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4- and 2,6-toluene diisocyanates, 1,5-naphthalene diisocyanate, 1-methoxy-2,4-phenylene diisocyanate, and 4,4′-xylene diisocyanate. -Biphenyl diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate and 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate; triisocyanates, such as 4,4′,4″-triphenylmethane triisocyanate and 2,4,6-toluene triisocyanate, and tetraisocyanates, such as 4,4′-dimethyl-2,2′-5,5′-diphenylmethane tetraisocyanate and 1,3-and / or 1,4-bis(2-isocyanate prop-2-yl)benzene (TMXDI), 1,3-bis(isocyanate methyl)benzene (XDI).

[0027] In addition to the isocyanates mentioned above, modified isocyanates may also be used, such as those containing structures of urea diketone, isocyanurate, carbodiimide, urea ketimide, urethane, or biuret, as well as modified isocyanates in the form of prepolymers obtainable by reacting one or more polyisocyanates with one or more polyols. The isocyanate may be a prepolymer obtainable by reacting an isocyanate having ≥2 NCO functionality with a polyol having a molecular weight of ≥62 g / mol to ≤8000 g / mol and an OH functionality of ≥1.5 to ≤6.

[0028] The polyisocyanate component A) is particularly preferably composed of at least one of monomeric MDI, oligomeric MDI, polymeric MDI and mixtures thereof.

[0029] The polyether polyol B1 according to the invention having a hydroxyl value (OHZ) of 20 to 50 mg KOH / g can be obtained by reacting a first H-functional initiator compound having a functionality f of ≥2 to ≤4 with ethylene oxide and propylene oxide.

[0030] Polyether polyol B1) can be one or more polyols.

[0031] The first H-functional initiator compound is preferably selected from ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, ethylenediamine, and triethanolamine, particularly preferably 1,2- and 1,3-propanediol, diethylene glycol, glycerol, and trimethylolpropane, and very particularly preferably one or more compounds of glycerol and trimethylolpropane.

[0032] In one embodiment of the invention, the mass ratio of propylene oxide in polyether polyol B1 is 60% to 90% by weight, preferably 70% to 85% by weight, based on the total amount of ethylene oxide and propylene oxide used.

[0033] In a preferred embodiment of the present invention, polyether polyol B1 can be obtained as follows:

[0034] i) React the first H-functional initiator compound with propylene oxide in the presence of a first catalyst to form a first intermediate.

[0035] ii) React the first intermediate with ethylene oxide to form a block copolymer.

[0036] In another, less preferred embodiment of the invention, the polyether polyol (B1) can be obtained by copolymerizing ethylene oxide and propylene oxide onto a first H-functional initiator compound in the presence of a first catalyst to form a copolymer.

[0037] In one embodiment of the invention, the first catalyst is potassium hydroxide, sodium hydroxide, cesium hydroxide, a bimetallic cyanide catalyst (DMC catalyst) and / or an amine, preferably potassium hydroxide.

[0038] The polyether polyol B2 according to the invention, having a hydroxyl value (OHZ) of 900-1100 mg KOH / g, can be obtained by reacting a second H-functional initiator compound having a functionality f of ≥2 to ≤4 with a second epoxide.

[0039] Polyether polyol B2) can be one or more polyols.

[0040] The second H-functional initiator compound is preferably selected from ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, ethylenediamine, and triethanolamine, particularly preferably 1,2- and 1,3-propanediol, diethylene glycol, glycerol, and trimethylolpropane, and very particularly preferably one or more compounds of glycerol and trimethylolpropane.

[0041] In one embodiment of the invention, polyether polyol B2 can be obtained by copolymerizing a second epoxide onto a second H-functional initiator compound in the presence of a second catalyst.

[0042] In one embodiment of the invention, the second catalyst is potassium hydroxide, sodium hydroxide, cesium hydroxide, a bimetallic cyanide catalyst (DMC catalyst), and / or an amine, preferably potassium hydroxide.

[0043] In one embodiment of the invention, the second alkyl oxide is propylene oxide and / or ethylene oxide, preferably propylene oxide.

[0044] The polyether polyol B3 according to the invention, having a hydroxyl value (OHZ) of >50 to <900 mg KOH / g, can be obtained by reacting a third H-functional initiator compound with propylene oxide.

[0045] Polyether polyol B3) can be one or more polyols.

[0046] In one embodiment, the third H-functional initiator compound has a functionality f of ≥2 to ≤4.

[0047] The third H-functional initiator compound is preferably selected from ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, ethylenediamine, and triethanolamine, particularly preferably 1,2- and 1,3-propanediol, diethylene glycol, glycerol, and trimethylolpropane, and very particularly preferably one or more compounds of 1,2-propanediol, glycerol, and trimethylolpropane.

[0048] In one embodiment of the invention, polyether polyol B3 can be obtained by copolymerizing a third epoxide onto a third H-functional initiator compound in the presence of a third catalyst.

[0049] In one embodiment of the invention, the third catalyst is potassium hydroxide, sodium hydroxide, cesium hydroxide, a bimetallic cyanide catalyst (DMC catalyst) and / or an amine, preferably potassium hydroxide.

[0050] In one embodiment of the invention, the third alkyl oxide is propylene oxide and / or ethylene oxide, preferably propylene oxide.

[0051] According to the present invention, in addition to the polyols B1), B2), and B3) used according to the present invention in the isocyanate reactive component B), other polyether polyols, other polyester polyols, other polyether ester polyols, and / or other polycarbonate polyols may be used. It is preferred to use other polyether polyols and / or other polyester polyols in B), and particularly preferred to use other polyether polyols.

[0052] In addition to the OH functional group, other polyols used in the isocyanate reactive component B may also contain other isocyanate reactive hydrogen atoms (=active hydrogen atoms), such as NH groups and NH2 groups. If such other active hydrogen atoms are present, preferably more than 90%, particularly more than 95%, particularly preferably more than 99%, and very particularly preferably 100% of all isocyanate reactive hydrogen atoms in the isocyanate reactive component are derived from the OH functional group.

[0053] For example, Ionescu describes such polyols in "Chemistry and Technology of Polyols for Polyurethanes", Rapra Technology Limited, Shawbury 2005, page 31 and thereafter (Chapter 3: The General Characteristics of Oligo-Polyols), page 55 and thereafter (Chapter 4: Oligo-Polyols for Elastic Polyurethanes), page 263 and thereafter (Chapter 8: Polyester Polyols for Elastic Polyurethanes), and especially on page 321 and thereafter (Chapter 13: Polyether Polyols for Rigid Polyurethane Foams) and page 419 and thereafter (Chapter 16: Polyester Polyols for Rigid Polyurethane Foams).

[0054] Preferably, the isocyanate reactive component B) is a polyol prepared by polymerization of an epoxide, such as propylene oxide and / or ethylene oxide, onto an H-functional initiator compound in the presence of a catalyst in a manner known per se. The polyhydroxy polyether is preferably made from an H-functional initiator compound having an average of 2 to 8 active hydrogen atoms and one or more epoxides, such as ethylene oxide, butane oxide, and / or propylene oxide. Preferred initiator compounds are molecules having 2 to 8 hydroxyl groups per molecule, such as water, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, and sucrose and amine initiator compounds, such as ethylenediamine and triethanolamine. The initiator compounds can be used alone or in combination. Particularly preferred are 1,2- and 1,3-propanediol, diethylene glycol, sorbitol, glycerol, trimethylolpropane, sucrose, and mixtures of the listed products. Representative descriptions of the isocyanate reactive component B) are, for example, Kunststoff-Handbuch, Vol. VII "Polyurethane", 3rd edition, Carl Hanser Verlag, Munich / Wien, 1993, pp. 57-67 and 88-90.

[0055] Polyester polyols are polyhydroxy compounds containing ester groups, such as castor oil or polyhydroxy polyesters, which can be obtained by polycondensation of an excess of a simple polyol of the type exemplified above with a preferred dicarboxylic acid or their anhydride, such as adipic acid, phthalic acid or phthalic anhydride.

[0056] Available catalysts (B4) include, for example, known polyurethane catalysts, organometallic compounds such as potassium or sodium salts of organic carboxylic acids, such as potassium acetate; tin(II) salts of organic carboxylic acids, such as tin(II) acetate, tin(II) octoate, tin(II) ethylhexanoate, and tin(II) laurate; and dialkyltin(IV) salts of organic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate, dimethyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate; and, for example, diisooctyl-2,2′-[(dioctylmethylenetinalkyl)bis(thio)]diacetate, di-n-butyl-bis(dodecylthio)tin, and isooctylthioacetic acid mono(di(octyl) ... Octyltin, isooctyl mercaptoacetate, 2-ethylhexyl 4,4′-dibutyl-10-ethyl-7-oxo-8-oxa-3,5-dithia-4-stanzatetradecanoate, dimethyltin dithioglycolate, and / or strongly basic amines such as 2,2,2-diazabicyclooctane, N,N-dimethylaminopropylamine, N,N-bis(3-dimethylaminopropyl)-N-isopropanolamine, triethylamine, triethylenediamine, tetramethylhexanediamine, pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine or bis(N,N-dimethylaminoethyl) ether, N,N-dimethylbenzylamine, N,N-methyldibenzylamine, and N-methylimidazolium and latent catalysts. Latent catalysts and their mechanisms of action are described, for example, on pages 1-4 and on page 9, line 26 to line 10, line 2 of EP 2531538 A1. Typical latent catalysts are blocked amine and amidine catalysts, such as catalysts from manufacturer Air Products (e.g.) SA-1 / 10, Dabco KTM 60) and catalysts from Tosoh Corporation (e.g. DB 2, DB 30, DB 31, DB 40, DB 41, DB 42, DB 60, DB 70). Further representatives of catalysts and a detailed description of their modes of action are in Kunststoff-Handbuch, Vol. VII "Polyurethane", 3rd edition, Carl Hanser Verlag, Munich / Wien, 1993, pp. 104-110.

[0057] In one embodiment of the invention, the amount of catalyst B4) is 0.05% to 5% by weight, preferably 0.05% to 2% by weight, based on the sum of the amounts of B), C) and D).

[0058] The desiccant B5 used is preferably a liquid desiccant (water-binding agent) or a dissolved desiccant (water-binding agent) at room temperature, i.e., 25°C. In this invention, the terms "desiccant" and "water-binding agent" are used synonymously.

[0059] In one embodiment of the invention, the amount of desiccant B5) is up to 5% by weight, preferably up to 2% by weight, in each case based on the sum of the amounts of B), C) and D.

[0060] In one embodiment of the invention, the amount of desiccant B5) is 0.05% to 5% by weight, preferably 0.05% to 2% by weight, based on the sum of the amounts of B), C) and D) in each case.

[0061] In one embodiment of the invention, the desiccant B5 is a trialkyl orthoformate, p-toluenesulfonyl isocyanate, oxazolidine, or a mixture thereof, preferably oxazolidine.

[0062] In a preferred embodiment, the desiccant B5) is an oxazolidine, and the oxazolidine is 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine and / or N-butyl-2-(1-ethylpentyl)-1,3-oxazolidine, with N-butyl-2-(1-ethylpentyl)-1,3-oxazolidine being particularly preferred.

[0063] Available internal release agents (C) include all release agents conventional in polyurethane production, such as long-chain monocarboxylic acids, particularly fatty acids such as stearic acid, amines of long-chain carboxylic acids such as stearamides, fatty acid esters, metal salts of long-chain fatty acids such as zinc stearate, or silicones. Particularly suitable are available internal release agents specifically for pultrusion molding, such as MOLD WIZ INT-1948MCH, MOLD WIZ INT-1947MCH, MOLD WIZ INT-1960MCH from AxelPlastics, or Luvotrent TL HB 550-D and Luvotrent TL HB 550 from Lehmann & Voss. The internal release agent is used in an amount of 0.1-8% by weight, preferably 0.1-6% by weight, and particularly preferably 0.1-4% by weight, based on the total weight of B).

[0064] Suitable auxiliaries and additives (D) include all auxiliaries and additives known for use in the production of polyurethane. Such substances are known and described, for example, in "Kunststoffhandbuch, Vol. 7, Polyurethane", Carl Hanser Verlag, 3rd edition, 1993, chapters 3.4.4 and 3.4.6 to 3.4.11. They include, for example, surfactants, defoamers, emulsifiers, viscosity reducers, dyes, pigments, flame retardants, and adhesion promoters.

[0065] Another subject of the present invention is a polyurethane composite material comprising a polyurethane and a fiber material that can be obtained from a polyurethane reactive system according to the present invention.

[0066] The fiber material is preferably at least one of inorganic fiber materials, organic fiber materials, metal fiber materials, natural fiber materials, and combinations thereof, especially glass fiber materials and carbon fiber materials or combinations thereof, with carbon fiber materials being particularly preferred.

[0067] Another subject of the present invention is a method for producing polyurethane pultruded parts according to the present invention, comprising the steps of:

[0068] i) Mix components A), B), C) and optional D) to obtain a polyurethane reactive system.

[0069] ii) Transfer the polyurethane reactive system from step i) to the injection chamber.

[0070] iii) Simultaneously with step ii), the fiber material is passed through an injection chamber to obtain fiber material impregnated with the polyurethane reactive system.

[0071] iv) Introduce the fiber material impregnated with the polyurethane reactive system into a heated curing mold.

[0072] v) Curing the fiber material impregnated with the polyurethane reactive system in a curing mold to obtain a polyurethane pultruded part.

[0073] vi) Use a pulling mechanism to pull the polyurethane pultruded part from step v) out of the curing mold.

[0074] vii) Cut the polyurethane pultruded part pulled from the cured mold to the required length.

[0075] The mixing of components A), B), C), and optional D) can be used in conventional methods for producing polyurethane reactive blends, such as in high-pressure or low-pressure processes. Premixing components B), C), and optional D) is preferred, and the resulting mixture is then mixed with component A).

[0076] During the impregnation of the fiber material in step iii), the temperature is preferably 0-75°C, particularly preferably 10-50°C, and very particularly preferably 15-35°C. The curing step v) is preferably carried out at a curing mold temperature of 140-220°C, wherein the curing mold preferably comprises multiple, preferably three or four, zones with different temperatures.

[0077] The fibrous material is in the form of continuous fibers. In this application, the term "continuous fiber" should be understood to refer to fibers known to those skilled in the art, such as inorganic fibers, organic fibers, metal fibers, natural fibers, preferably glass fibers and carbon fibers, with carbon fibers being particularly preferred. Here, the term "continuous fiber" should be understood to refer to fibrous material having a length of at least several meters. The fibers are unwound, for example, from rollers or spools. Fiber materials available here include monofilaments, so-called rovings, braided fibers, fiber mats, fiber layups, and woven fiber fabrics. Especially in the case of fiber composites such as braided fibers, twisted fibers, or woven fiber fabrics, shorter monofilaments may also be included among the monofilaments contained in these fiber composites. However, the fiber composite itself must be in the form of a continuous material. In a preferred embodiment of the invention, the fibers are used in the form of rovings.

[0078] In another preferred embodiment of the invention, in step iii), in addition to the fibrous material, a release woven fabric (so-called release cloth) is passed through the injection chamber so that it preferably forms at least two outer sides of the finished polyurethane pultruded part. In further processing of the polyurethane pultruded part according to the invention, this release woven fabric on the outer sides can be removed to form at least two roughened surfaces, thereby, for example, promoting the adhesion of the polyurethane pultruded part.

[0079] The polyurethane pultruded parts according to the invention can be used, for example, in the production of reinforcing profiles or structural elements in vehicle structures, aircraft structures, or wind power generation devices. Such lightweight reinforcing profiles can be used, for example, in the production of so-called "beam caps" in the rotor blades of wind power generation devices.

[0080] The invention will be explained in more detail in the following embodiments. Example

[0081] A pultrusion molding apparatus was used, featuring a heated die with internal dimensions of 60mm x 5mm and an injection chamber positioned upstream of the die. Accordingly, right-angled profiles with a width of 60mm and a wall thickness of 5mm were manufactured. Carbon fiber roving (from Mitsubishi Rayon Co., Ltd.) was used. TRW 40 50L KNA was used as the fiber material and pulled through the injection box and mold. The carbon fiber concentration in the finished profile was approximately 65% ​​by volume. The amount of internal release agent shown in each case was added to the polyol mixtures listed in Table 1 and vigorously stirred. These mixtures were mixed with such a large amount of isocyanate at 23°C in each case using a low-pressure mixer with a static mixer to achieve the NCO index shown in Table 1 for each case, and the resulting polyurethane reactive system was continuously injected into the injection box. The impregnated reinforcing fibers were continuously pulled through a heated mold and cured using the traction mechanism of the pultrusion molding unit. The mold temperature was divided into three zones: zone 1 at 170°C (mold inlet in the traction direction), zone 2 at 200°C (mold center), and zone 3 at 220°C (mold outlet). The finished profiles were then continuously cut to the desired length.

[0082] Use the following raw materials:

[0083] Isocyanate component A)

[0084] MDI 1: Polymerized MDI with 32.4% by weight NCO content and 80% by weight monomeric MDI content; the total content of 2,4′-MDI and 2,2′-MDI is 25% by weight, Covestro Deutschland AG.

[0085] Isocyanate reactive component B)

[0086] Polyether polyol B1)

[0087] Polyol 6: A polyether polyol having OHZ = 29 mg KOH / g and a propylene oxide (PO) ratio of 78.1 wt% based on the mass of PO and EO used and a ethylene oxide (EO) ratio of 21.9 wt% based on the mass of PO and EO used, which can be obtained by reacting glycerol (F = 3) with propylene oxide in the presence of a KOH catalyst and then reacting a propoxylation intermediate with ethylene oxide to form a polyether polyol block copolymer.

[0088] Polyether polyol B2)

[0089] Polyol 2: A triol starting from glycerol, propoxylated, OHZ = 1050 mg KOH / g

[0090] Polyether polyol B3)

[0091] Polyol 1: A triol starting from glycerol, propoxylated, OHZ = 235 mg KOH / g

[0092] Polyol 3: A triol starting from glycerol, propoxylated, OHZ = 400 mg KOH / g

[0093] Polyol 5: A diol starting from propylene glycol, propoxylated, OHZ = 515 mg KOH / g

[0094] Other polyether polyols

[0095] Polyol 4: A diol starting from propylene glycol, propoxylated, OHZ = 28 mg KOH / g

[0096] Polyol 7: A polyether monool having OHZ = 3 mg KOH / g and a propylene oxide (PO) ratio of 52.9 wt% based on the mass of PO and EO used and a ethylene oxide (EO) ratio of 47.1 wt% based on the mass of PO and EO used, which can be obtained by reacting butyl diethylene glycol (F = 1) with propylene oxide and ethylene oxide in the presence of a KOH catalyst and then reacting this intermediate with propylene oxide to form a polyether monool block copolymer.

[0097] Catalyst B4)

[0098] Catalyst: 2,2′-[(dioctylmethylenetinyl)bis(thio)]diacetate diisooctyl ester

[0099] Desiccant B5) as a water binder

[0100] Water binder 1: from UOP L-powder

[0101] Water binder 2: Incozol-2 (N-butyl-2(1-ethylpentyl)-1,3-oxazolidine) from Incorez

[0102] Release agent C)

[0103] Internal release agent (IMR): from Lehmann & Voss, used in pultrusion molding. TL HB 550

[0104] All quantities in Table 1 are shown in parts by weight. Mechanical characteristics were determined by the following methods:

[0105] • Transverse bending stress: DIN EN ISO 14125

[0106] • Axial bending stress: DIN EN ISO 178

[0107] • Interlaminar shear strength (ILSS): DIN EN ISO 14130

[0108] ·Axis ILSS: DIN EN ISO 14130

[0109] In addition, during the production of polyurethane pultruded parts, traction force and traction speed are measured in the pultrusion unit, and fiber impregnation, surface quality, and wear occurrence are visually assessed.

[0110] The single-phase nature of the isocyanate reactive components used was also visually tested. For this purpose, the isocyanate reactive components used in Examples 1-6 were stored at room temperature in transparent plastic containers for 6 months, and visual inspections were performed periodically. Here, multiphase nature describes any occurrence of inhomogeneities, such as phase separation, turbidity, and droplet formation. Accordingly, the single-phase isocyanate reactive component did not exhibit any of these effects after 6 months at room temperature. The single-phase isocyanate reactive component was a homogeneous, clear liquid. Furthermore, the single-phase isocyanate reactive component did not exhibit any of the aforementioned multiphase effects when centrifuged at 6000 rpm for 30 minutes.

[0111] Table 1

[0112]

[0113]

[0114] Example 1 corresponds to the composition of the present invention. The isocyanate reactive component is solid-free and single-phase, resulting in pultruded parts with good processability and good mechanical properties.

[0115] Example 2 represents a known system composition based on zeolite-based (water binder 1), i.e., containing a solid and therefore unstable isocyanate reactive component. The reactive system of the present invention has the advantage of not exposing the pump and filter to any solids and offering easier or better transport and processability.

[0116] Examples 3 and 4 show that systems 1 and 2, which do not use a water binder, have poor processability and poor mechanical properties. This indicates that a single-phase reactive system without solids is insufficient on its own to combine good processability with good mechanical properties in the resulting pultruded parts.

[0117] Example 5 shows that, while the other components of the isocyanate reactive component are the same as in Example 2, simply replacing water binder 1 with water binder 2 yields a solid-free system, but this does not guarantee good processability and mechanical properties of the pultruded parts. Furthermore, due to the polyether composition, the system remains multiphase, exhibiting the disadvantages described above during processing.

[0118] Example 6 also shows a solid-free single-phase system. However, it is clear that only the composition of component B) according to the present invention yields pultruded parts with good mechanical properties.

Claims

1. A polyurethane reactive system, which includes Isocyanate component A), Isocyanate reactive component B), which contains 3-13% by weight of polyether polyol B1 with a hydroxyl value of 20 to 50 mg KOH / g, obtained by reacting a first H-functional initiator compound with a functionality f of ≥2 to ≤4 with ethylene oxide and propylene oxide, wherein for polyether polyol B1), the mass proportion of propylene oxide is 60% to 90% by weight based on the total amount of ethylene oxide and propylene oxide used. 15-37% by weight of polyether polyol B2 with a hydroxyl value of 900-1100 mg KOH / g, which is obtained by reacting a second H-functional initiator compound with a functionality f of ≥2 to ≤4 with a second epoxide. 50-72% by weight of polyether polyol B3 with a hydroxyl value of >50 to <900 mg KOH / g, obtained by reacting a third H-functional initiator compound with a third epoxide. One or more catalysts (B4) and Desiccant B5), wherein the desiccant B5) used is a liquid desiccant at room temperature (25°C). The sum of the weight percentages of components B1) and B2) based on the sum of the amounts of B), C), and D) is ≤ 40% by weight, and the sum of the weight percentages of components B1), B2), B3), B4), and B5) based on the sum of the amounts of B), C), and D) is ≥ 90% by weight. Internal release agent C), And optionally, other auxiliaries and additives (D), The total weight percentage of components B), C), and optional D) is 100% by weight. Furthermore, the hydroxyl values ​​of the polyether polyols B1), B2) and B3) were determined using ISO 14900.

2. The polyurethane reactive system as described in claim 1, wherein the amounts of components A), B), C) and optional D) are such that the ratio of the number of NCO groups in A) to the sum of the number of OH isocyanate reactive groups in B), C) and D) multiplied by 100 has a value of 100-150.

3. The polyurethane reactive system as described in claim 1 or 2, wherein the amount of desiccant B5) is at most 5% by weight, based on the sum of the amounts of B), C) and D) in each case.

4. The polyurethane reactive system according to any one of claims 1 to 2, wherein the amount of desiccant B5) is 0.05% to 5% by weight based on the sum of the amounts of B), C) and D).

5. The polyurethane reactive system according to any one of claims 1 to 2, wherein the desiccant B5) is trialkyl orthoformate, p-toluenesulfonyl isocyanate, oxazolidine, or a mixture thereof.

6. The polyurethane reactive system as described in claim 5, wherein the desiccant B5) is an oxazolidine and the oxazolidine is 3-ethyl-2-methyl-2-(3-methylbutyl)-1,3-oxazolidine and / or N-butyl-2-(1-ethylpentyl)-1,3-oxazolidine.

7. The polyurethane reactive system according to any one of claims 1 to 2, wherein for polyether polyol B1), the mass ratio of propylene oxide is 70% to 85% by weight based on the total amount of ethylene oxide and propylene oxide used.

8. The polyurethane reactive system according to any one of claims 1 to 2, wherein the polyether polyol (B1) is obtained as follows: i) React the first H-functional initiator compound with propylene oxide in the presence of a first catalyst to form a first intermediate. ii) React the first intermediate with ethylene oxide.

9. The polyurethane reactive system as described in claim 8, wherein the first catalyst is potassium hydroxide, sodium hydroxide, cesium hydroxide, a bimetallic cyanide catalyst, and / or an amine.

10. The polyurethane reactive system according to any one of claims 1 to 2, wherein the second epoxide is propylene oxide and / or ethylene oxide.

11. The polyurethane reactive system according to any one of claims 1 to 2, wherein the third epoxide is propylene oxide and / or ethylene oxide.

12. The polyurethane reactive system according to any one of claims 1 to 2, wherein the amount of catalyst B4) is 0.05% to 5% by weight based on the sum of the amounts of B), C) and D).

13. A polyurethane composite material comprising a polyurethane and a fiber material obtained from a polyurethane reactive system as described in any one of claims 1 to 12.

14. A pultrusion molding method for producing the polyurethane composite material as described in claim 13, comprising the steps of: i) Mixing components A), B), C) and optionally D) to obtain the polyurethane reactive system as described in any one of claims 1 to 3. ii) Transfer the polyurethane reactive system from step i) to the injection chamber. iii) Simultaneously with method step ii), the fiber material is passed through an injection chamber to obtain fiber material impregnated with the polyurethane reactive system. iv) Introduce the fiber material impregnated with the polyurethane reactive system into a heated curing mold. v) Curing the fiber material impregnated with the polyurethane reactive system in a curing mold to obtain a polyurethane pultruded part. vi) Use a pulling mechanism to pull the polyurethane pultruded part from step v) out of the curing mold. vii) Cut the polyurethane pultruded part pulled from the cured mold to the required length.

15. Use of the polyurethane composite material as described in claim 13 for the production of reinforcing profiles or structural components or elements in vehicle structures, aircraft structures or wind power generation devices.

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