Non-ionically hydrophilized polyurethane dispersions with acrylate double bonds

Description

[0001] The present invention relates to an aqueous UV-curable dispersion comprising at least one reaction product composed of a) at least one polyisocyanate having an average isocyanate functionality of at least 2.2, of which at least one polyisocyanate is preferably an oligomeric polyisocyanate having urethane, biuret, allophanate, iminooxadiazinedione and / or isocyanurate structural units, b) at least one monohydroxy-functional compound containing acryloyl groups, c) at least one component containing non-ionically hydrophilizing groups and having at least one isocyanate-reactive group, and d) at least one diol, triol, diamine and / or triamine, wherein the reaction product does not contain any ionogenic or ionically hydrophilizing groups, a process for its preparation, the use of the dispersion for the production of glass fiber sizings, a glass fiber sizing comprising at least such a dispersion,Glass fibers coated with a size obtainable using such a dispersion, a process for producing glass fiber-reinforced plastics, and a corresponding glass fiber-reinforced plastic. The invention is set out in the appended set of claims.

[0002] Aqueous coating compositions based on functionalized polyisocyanates are known to those skilled in the art. They are combined, for example, to form single-component coating compositions and used for coating glass fibers, e.g., for glass fiber-reinforced plastics. After application to the glass fibers, the water is first removed. The resulting film, known as the sizing, is crosslinked by the reaction of the latent polyisocyanates. Further crosslinking by the reaction of the polyisocyanates contained in the sizing occurs when the glass fibers are incorporated into the plastics.

[0003] The document EP 1 516 012 B1 discloses a glass fiber sizing composition comprising at least one water-dispersible or water-soluble, blocked polyisocyanate (A), at least one polyurethane (B) containing radically polymerizable groups and an initiator (C) which can trigger a radical polymerization.

[0004] The document DE 10 2009 008 949 A1 describes radiation-curable coating systems based on aqueous polyurethane dispersions containing as structural components one or more oligomeric or polymeric compounds having at least one isocyanate-reactive group and at least one radically copolymerizable group, optionally one or more monomeric compounds having a hydroxyl function and at least one (meth)acrylate group, polyester polyols, optionally further polyols, one or more compounds having at least one isocyanate-reactive group and additionally ionic groups or groups capable of forming ionic groups or a combination of non-ionic and ionic groups or groups capable of forming ionic groups which have a dispersing effect on the polyurethane dispersion, and organic polyisocyanates.

[0005] EP2581396A1 discloses processes for the preparation of low-viscosity, water-soluble urethane (meth)acrylates.

[0006] DE3336845A1 discloses sizing agents for glass fibers DE19914822A1 discloses self-crosslinking polyurethane dispersions for coating applications, e.g. for sizing glass fibers, containing blocked isocyanate groups and reactive hydroxyl or amino groups on the polymer or in an additional reaction component.

[0007] DP2322576A2 discloses photopolymerized resin compositions and optical fibers made therewith.

[0008] The acrylate-functional coating agents known from the prior art show a lack of compatibility in typical formulations for glass fiber sizing, which, for example, significantly limits the processing time. One problem with the use of functional silanes in glass fiber sizing is that the complex hydrolysis and condensation processes of the other components in combination with functional silanes in typical glass fiber sizing often produce (intermediate) products that lead to unstable systems. Highly compatible coating agents for glass fibers with (reactive) acrylate groups are not described in the prior art.

[0009] The object of the present invention was therefore to provide a purely non-ionically hydrophilized, functionalized, acrylate-containing polyisocyanate, particularly for use as a glass fiber sizing agent, and a process for its preparation. A further object of the present invention is to provide an aqueous dispersion of a corresponding polyisocyanate with sufficiently high storage stability.

[0010] These objects are achieved according to the invention by an aqueous UV-curable dispersion containing at least one reaction product composed of a) at least one polyisocyanate having an average isocyanate functionality of at least 2.2, of which at least one polyisocyanate is preferably an oligomeric polyisocyanate having urethane, biuret, allophanate, iminooxadiazinedione and / or isocyanurate structural units, b) at least one monohydroxy-functional compound containing acryloyl groups, c) at least one component containing non-ionically hydrophilizing groups and having at least one isocyanate-reactive group, d) at least one diol, triol, diamine and / or triamine, wherein the at least one diol, triol, diamine and / or triamine preferably has a molecular weight of < 400 g / mol, wherein the reaction product does not contain any ionogenic or ionically hydrophilizing groups.

[0011] The dispersions according to the invention thus comprise a functionalized polyisocyanate which contains acrylate groups polymerizable by high-energy radiation or by the addition of radical initiators such as peroxide hardeners or azo-based hardeners and no longer contains free isocyanate groups.

[0012] The reaction product present in the UV-curable dispersion according to the invention is obtained or is obtainable from the reaction of the components: 35 to 75% by weight, particularly preferably 40 to 75% by weight, very particularly preferably 45 to 65% by weight, of component a), 10 to 50% by weight, particularly preferably 12 to 35% by weight, very particularly preferably 14 to 32% by weight of component b), 5 to 40% by weight, particularly preferably 7 to 30% by weight, very particularly preferably 15 to 25% by weight of component c), and 0.1 to 25% by weight, particularly preferably 0.1 to 9% by weight, very particularly preferably 0.1 to 5% by weight of component d), where the percentages from a) to d) each add up to 100% by weight.

[0013] The dispersion according to the invention optionally contains auxiliaries and additives, for example those that enable or accelerate curing with high-energy radiation, such as electron beams or UV rays, or a radical reaction. In a preferred embodiment, the dispersion contains stabilizers to prevent premature curing, selected from the group consisting of phenols, sterically hindered amines, and / or thiazines.

[0014] The dispersion according to the invention generally has an acid number below 50 mg KOH / g polymer, preferably below 20 mg KOH / g polymer, particularly preferably below 10 mg KOH / g polymer, and particularly preferably below 5 mg KOH / g polymer. The acid number indicates the mass of potassium hydroxide in mg required to neutralize 1 g of the sample to be analyzed (measured according to EN ISO 660 (2009 version)). The neutralized acids, i.e., the corresponding salts, naturally have no or a reduced acid number. According to the invention, the acid number of the corresponding free acid is decisive here.

[0015] The dispersion according to the invention generally has a zeta potential of -50 to +50 mV, preferably -15 to +15 mV, and particularly preferably -2 to +10 mV. The zeta potential is determined by measuring a sample diluted with demineralized water in a "ZetaSizer 3000HSA" (Malvem Instruments, Herrenberg, Germany) at 23°C.

[0016] The urethane group content (MW urethane group = 59 g / mol) of the dispersion according to the invention is generally 3 to 30 wt.%, preferably 10 to 25 wt.%, in each case based on the solids content.

[0017] Polyisocyanates a) suitable according to the invention are, in addition to the oligomeric polyisocyanates with preferably urethane, biuret, allophanate, iminooxadiazinedione and / or isocyanurate structural units, at least difunctional polyisocyanates such as 1,4-, 1,3-, and / or 1,2-cyclohexane diisocyanate, 1-methyl-2,4-diisocyanatocyclohexane, 1-methyl-2,6-diisocyanatocyclohexane, tetramethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, H 6 -2,4- and / or -2,6- diisocyanatotoluene, 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, 2,2'-diisocyanatodiphenylmethane, meta- and / or para-xylylene diisocyanate, 2,4-diisocyanatotoluene and / or 2,6-Diisocyanatotoluene, Isopropenyldimethyltoluene diisocyanate, α,α,α,'α,'-Tetra-methyl-m- and / or -p-xylylene diisocyanate, 1,6-Hexamethylene diisocyanate, Trimethylhexane diisocyanate, Tetramethylhexane diisocyanate, Nonane triisocyanate, 1-Isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (Isophorone diisocyanate), 4,4'-Diisocyanatodicyclohexylmethane and / or 2,4'-diisocyanatodicyclohexylmethane and / or 2,2'-diisocyanatodicyclohexylmethane, as well as mixtures of these diisocyanatodicyclohexylmethanes and their mono- and dimethyl-substituted derivatives, and / or higher-functionality reaction products, homologues, oligomers, and / or polymers of the above-mentioned at least difunctional polyisocyanates with urethane, biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione, and / or uretdione structural units. Monofunctional isocyanates, such as stearyl isocyanate, butyl isocyanate, phenyl isocyanate, or others such as 3-isocyanatopropyltrialkoxysilane, may also be used in proportion.

[0018] The average isocyanate functionality of the polyisocyanate component a) is preferably 2.2 to 6, particularly preferably 2.4 to 5, most particularly preferably 2.6 to 4.5.

[0019] The polyisocyanate component a) preferably has a viscosity of less than 25,000 mPa·s at 23 °C, particularly preferably less than 15,000 mPa·s at 23 °C.

[0020] Preferably, the polyisocyanate component a) consists of at least 40 wt. % of liquid oligomeric polyisocyanates based on hexamethylene diisocyanate with isocyanurate, biuret, uretdione, carbodiimide, allophanate and / or iminooxadiazinedione structural units and of at most 60 wt. % of isophorone diisocyanate, H 6 -2,4- or -2,6-toluylidene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4'-diisocyanatodicyclohexylmethane and / or 2,4'-diisocyanatodicyclohexylmethane and / or 2,2'-diisocyanatodicyclohexylmethane and / or 2,4- or 2,6-toluylidene diisocyanate or their reaction products with trimethylolpropane, butanediol, ethylene glycol, diethylene glycol, propylene glycol or Neopentyl glycol.

[0021] Particularly preferably, the polyisocyanate component a) consists of at least 70 wt. % oligomeric polyisocyanates based on hexamethylene diisocyanate with biuret, iminooxadiazinedione, allophanate and / or isocyanurate structural units and of a maximum of 30 wt. % isophorone diisocyanate, 4,4'-diisocyanatodicyclohexylmethane and / or 2,4'-diisocyanatodicyclohexylmethane and / or 2,2'-diisocyanatodicyclohexylmethane and / or 2,4- or 2,6-toluylidene diisocyanate.

[0022] Suitable components b) are compounds containing monohydroxyfunctional acryloyl groups, such as hydroxyethyl acrylate, 2- / 3-hydroxypropyl acrylate, hydroxybutyl acrylate, 2- / 3- / 4-hydroxyethyl acrylate, 2- / 3-hydroxypropyl acrylate, 2- / 3- / 4-hydroxybutyl acrylate, ethoxylation and / or propoxylation products of the above-mentioned hydroxyacrylates, reaction products of trimethylopropane, glycerol and / or pentaerythritol or their ethoxylation and / or propoxylation products with 2 or 3 equivalents of acrylic acid, reaction products of the above-mentioned hydroxyacrylates with caprolactone, reaction products of monoepoxides, such as Cardura ®< E10 (monoepoxide, Hexion Speciality Chemicals, Netherlands) with acrylic acid and mixtures of the above-mentioned compounds containing monohydroxyfunctional acryloyl groups.

[0023] According to the invention, hydroxyethyl acrylate, hydroxypropyl acrylate and / or hydroxybutyl acrylate are preferably used as component b).

[0024] The dispersion according to the invention further comprises at least one component c) which contains non-ionically hydrophilizing groups and at least one further isocyanate-reactive group. Component c) according to the invention preferably has one or two, preferably one, isocyanate-reactive groups and non-ionically hydrophilizing structural units, preferably based on polyalkylene oxide.

[0025] Suitable non-ionic hydrophilic components c) include, for example, polyoxyalkylene ethers containing at least one hydroxyl or amino group. These polyethers contain 30 to 100 wt. % of building blocks derived from ethylene oxide. Suitable polyethers include linear polyethers with a functionality between 1 and 3, but also compounds of the general formula (I), in which R 1< and R 2< independently of one another each represent a divalent aliphatic, cycloaliphatic or aromatic radical having 1 to 18 C atoms, which may be interrupted by oxygen and / or nitrogen atoms, and R 3< represents an alkoxy-terminated polyethylene oxide radical.

[0026] Non-ionic hydrophilic compounds also include, for example, monovalent polyalkylene oxide polyether alcohols containing on average 5 to 70 ethylene oxide units per molecule, as are obtainable in a conventional manner by alkoxylation of suitable starter molecules, see, for example, Ullmann's Encyclopedia of Industrial Chemistry, 4th edition, Volume 19, Verlag Chemie, Weinheim, pages 31 to 38.

[0027] Suitable starter molecules are, for example, saturated monoalcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, the isomers pentanols, hexanols, octanols and nonanols, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, cyclohexanol, the isomeric methylcyclohexanols or hydroxymethylcyclohexane, 3-ethyl-3-hydroxymethyloxetane or tetrahydrofurfuryl alcohol, diethylene glycol monoalkyl ethers such as diethylene glycol monobutyl ether, unsaturated alcohols such as allyl alcohol, 1,1-dimethylallyl alcohol or olein alcohol, aromatic alcohols such as phenol, the isomeric cresols or methoxyphenols, araliphatic alcohols such as benzyl alcohol, anise alcohol or Cinnamyl alcohol, secondary monoamines such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, bis-(2-ethylhexyl)amine, N-methyl- and N-ethylcyclohexylamine or dicyclohexylamine as well as heterocyclic secondary amines such as morpholine, pyrrolidine,Piperidine or 1H-pyrazole. Preferred starter molecules are saturated monoalcohols. Diethylene glycol monomethyl, monoethyl, or monobutyl ether is particularly preferred as the starter molecule.

[0028] Alkylene oxides suitable for the alkoxylation reaction are, in particular, ethylene oxide and propylene oxide, which can be used in any order or in a mixture in the alkoxylation reaction.

[0029] The polyalkylene oxide polyether alcohols are either pure polyethylene oxide polyethers or mixed polyalkylene oxide polyethers whose alkylene oxide units consist of at least 30 mol%, preferably at least 50 mol%, of ethylene oxide units.

[0030] Particularly preferred non-ionic compounds c) are monohydroxy-functional polyalkylene oxide polyethers which have at least 75 mol% ethylene oxide, particularly preferably 100 mol% ethylene oxide units and a number-average molecular weight in the range from 350 to 2500 g / mol, particularly preferably in the range from 500 to 1100 g / mol, determined according to DIN EN ISO 13885-2:2021 by gel permeation chromatography (GPC) in DMAc (N,N-dimethylacetamide) as eluent at 23 °C, after calibration with polystyrene standards.

[0031] The reaction product contained in the dispersion according to the invention does not contain any ionogenic, ie potentially ionic, or ionically hydrophilizing groups. Preferably, the reaction product contained in the dispersion according to the invention does not contain any of the ionogenic or ionically hydrophilizing groups or compounds mentioned below. Particularly preferably, the reaction product contained in the dispersion according to the invention does not contain any ionically hydrophilizing groups, ieThe following building blocks are preferably not used in the reaction from a) to d): mono- and dihydroxycarboxylic acids, mono- and diaminocarboxylic acids, mono- and dihydroxysulfonic acids, mono- and diaminosulfonic acids and mono- and dihydroxyphosphonic acids or mono- and diaminophosphonic acids and their salts such as dimethylolpropionic acid, dimethylolbutyric acid, hydroxypivalic acid, N-(2-aminoethyl)alanine, 2-(2-aminoethylamino)ethanesulfonic acid, ethylenediamine-propyl- or butylsulfonic acid, 1,2- or 1,3-propylenediamineethylsulfonic acid, malic acid, citric acid, glycolic acid, lactic acid, glycine, alanine, taurine, lysine, 3,5-diaminobenzoic acid, an addition product of IPDI and acrylic acid (EP-A 0 916 647, Example 1) and its alkali and / or ammonium salts; the adduct of sodium bisulfite to butene-2-diol-1,4, polyethersulfonate, the propoxylated adduct of 2-butenediol and NaHSO 3 , e.g.described in DE-A 2 446 440 (pages 5-9, formula I-III), N-methyldiethanolamine, compounds which have carboxy or carboxylate and / or sulfonate groups and / or ammonium groups, in particular compounds which contain carboxyl and / or sulfonate groups as ionic or potentially ionic groups, such as the salts of 2-(2-aminoethylamino)ethanesulfonic acid or the addition product of diamines such as ethylenediamine or isophoronediamine and acrylic acid (EP-A 0 916 647, Example 1) and dimethylolpropionic acid.

[0032] In the context of the present invention, "no ionogenic or ionically hydrophilizing groups" means that, in general, based on the reaction product contained in the dispersion according to the invention, there are no less than less than 100 milliequivalents per 100 g of polyurethane polymer, preferably less than 25 milliequivalents, more preferably less than one milliequivalent and most preferably less than 1 milliequivalent per 100 g of the polymer.

[0033] Components d) are diols, triols, diamines, and / or triamines, which serve to extend the chain or increase the molecular weight. The chain-extension reaction between the amino groups and the isocyanate groups forms urea structural units in the polyurethane polyacrylate dispersions.

[0034] Examples of components d) that may be mentioned are ethylenediamine, 1,3-propylenediamine, 1,6-hexamethylenediamine, 1,4-butanediamine, hydrazine (hydrate), amino-functional polyethylene oxides or polypropylene oxides, which are available, for example, under the name Jeffamin® (Huntsman Corp. Europe, Belgium), alkoxysilane-containing mono- or diamines, diethylenetriamine, and isophoronediamine. Preference is given to linear aliphatic diamines such as ethylenediamine, hydrazine (hydrate), or 1,6-hexamethylenediamine, and optionally aliphatic triamines such as diethylenetriamine. If component d) is used according to the invention, it is used in an amount such that the degree of chain extension is 30 to 200%, preferably 50 to 150%, particularly preferably 70 to 110%.

[0035] The degree of chain extension is defined as the ratio of the amount of equivalents of amino groups in component d) to the amount of equivalents of isocyanate groups in prepolymer A), which is obtained by reacting components a), b), and c). A degree of chain extension of 100% according to this definition is obtained when the amount of equivalents of amino groups in component d) exactly corresponds to the amount of equivalents of isocyanate groups in prepolymer A).

[0036] Diols and triols that can be used include, for example, low-molecular-weight alcohols such as butanediol, hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tetraethylene glycol, and / or trimethylolpropane, as well as ethoxylated and / or propoxylated diols and / or triols, e.g., based on diethylene glycol or trimethylpropane. Partial or complete incorporation into the polymer is possible via the hydroxyl groups. The number-average molecular weights are or were determined according to DIN EN ISO 13885-2:2021 by gel permeation chromatography (GPC) in DMAc (N,N-dimethylacetamide) as the eluent at 23 °C, after calibration with polystyrene standards.

[0037] Oligoesters are obtained by esterification of carboxylic acids such as adipic acid, isophthalic acid, phthalic anhydride, maleic anhydride, fumaric acid, tetrahydrophthalic acid, hexahydrophthalic acid, dimer fatty acid, soybean oil fatty acid, benzoic acid, and / or glutaric acid with alcohols such as neopentyl glycol, hexanediol, ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, TCD diol, trimethylolpropane, glycerol, and / or pentaerythritol. Preference is given to the use of adipic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, and / or hexahydrophthalic anhydride with neopentyl glycol, ethylene glycol, diethylene glycol, glycerol, and / or trimethylolpropane. Particularly preferred is the use of isophthalic acid or phthalic anhydride, optionally in combination with adipic acid and neopentyl glycol, optionally in combination with trimethylolpropane.

[0038] In a preferred embodiment, low molecular weight diols such as butanediol, hexanediol, neopentyl glycol, ethylene glycol, propylene glycol and / or polymer diols are used as component d).

[0039] In a further preferred embodiment, oligoesters with OH numbers of 240 to 500 mg KOH / g (determined according to DIN EN ISO 4629-2:2016), preferably 300 to 500 mg KOH / g substance, and a number-average molecular weight Mw in the range of 200 to 400 g / mol, preferably in the range of 250 to 390 g / mol, are used as component d). The number-average molecular weights are or were determined according to DIN EN ISO 13885-2:2021 by gel permeation chromatography (GPC) in DMAc (N,N-dimethylacetamide) as the eluent at 23 °C, after calibration with polystyrene standards.

[0040] In a preferred embodiment, component d) is selected from the group consisting of butanediol, hexanediol, neopentyl glycol, ethylene glycol, propylene glycol, ethylenediamine, isophoronediamine, hydrazine (hydrate), 1,6-hexamethylenediamine, diethylenetriamine and / or polymer diols, wherein the polymer diols preferably have a number-average molecular weight in the range from 700 to 2200 g / mol, determined according to DIN EN ISO 13885-2:2021 by gel permeation chromatography (GPC) in DMAc (N,N-dimethylacetamide) as eluent at 23 °C, after calibration with polystyrene standards, particularly preferably component d) is selected from the group consisting of butanediol, hexanediol, neopentyl glycol, ethylene glycol, propylene glycol, ethylenediamine, isophoronediamine, hydrazine (hydrate), 1,6-hexamethylenediamine and / or diethylenetriamine.

[0041] The dispersion according to the invention can also be used in a mixture with other aqueous dispersions. These can be dispersions that also contain unsaturated groups, such as unsaturated, polymerizable group-containing dispersions based on polyester, polyurethane, polyepoxide, polyether, polyamide, polysiloxane, polycarbonate, polymer, and / or polyacrylate.

[0042] Dispersions based on polyesters, polyurethanes, polyepoxides, polyethers, polyamides, polyvinyl esters, polyvinyl ethers, polysiloxanes, polycarbonates, polymers, or polyacrylates containing functional groups such as alkoxysilane groups, hydroxyl groups, or isocyanate groups can also be added. This allows, for example, the production of dual-cure systems that can be cured using two different mechanisms.

[0043] Coating compositions containing the UV-curable polyisocyanate-based dispersions according to the invention, as well as crosslinkers based on amino resins and / or polyisocyanates and / or blocked polyisocyanates are also subject of the present invention.

[0044] Suitable amino crosslinking resins include, for example, those based on melamine or urea. Suitable polyisocyanates include, for example, those mentioned under the description of a). Generally suitable hydrophilizing agents for the polyisocyanates, such as those based on polyether, are mentioned in the description of c). Suitable blocking agents include, for example, methanol, ethanol, butanol, hexanol, benzyl alcohol, acetoxime, butanone oxime, caprolactam, phenol, diethyl malonate, diethyl malonate, dimethylpyrazole, triazole, dimethyltriazole, acetoacetic ester, diisopropylamine, dibutylamine, tert-butylbenzylamine, cyclopentanone carboxyethyl ester, dicyclohexylamine, and / or tert-butylisopropylamine.

[0045] Dispersions based on polyesters, polyurethanes, polyepoxides, polyethers, polyamides, polysiloxanes, polyvinyl ethers, polybutadienes, polyisoprenes, chlorinated rubbers, polycarbonates, polyvinyl esters, polyvinyl chlorides, polymers or polyacrylates which do not have any functional groups can also be added.

[0046] Also suitable for combination with the dispersions according to the invention are so-called reactive diluents, low-viscosity compounds containing unsaturated groups, such as hexanediol bisacrylate, trimethylolpropane trisacrylate, trimetholpropane diacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, or diepoxide bisacrylates based on bisphenol A. The present invention also relates to binder combinations containing the UV-curable polyisocyanate-based dispersions according to the invention, as well as one or more further dispersions.

[0047] The dispersion according to the invention can also be used in a mixture with water-insoluble or water-dispersible oligomers or polymers containing unsaturated groups, wherein the water-insoluble or water-dispersible oligomers or polymers containing unsaturated groups are added to the dispersion according to the invention before dispersion, whereby the dispersion according to the invention serves as polymeric emulsifiers for these substances. Preferred mixtures are binder combinations containing the dispersion according to the invention, as well as water-insoluble or water-dispersible oligomers or polymers containing unsaturated groups.

[0048] The invention also relates to a process for preparing the dispersion according to the invention, wherein an isocyanate-functional prepolymer A) is obtained by reacting components b) and c) in one or more reaction steps with an excess of component a), followed by the dispersing step by adding water to the prepolymer A) or transferring the prepolymer A) into an aqueous initial charge, followed by a chain extension step by adding component d).

[0049] The invention also relates to a process for preparing the dispersion according to the invention, wherein an isocyanate-functional prepolymer A) is obtained by reacting components a), b), and c) in one or more reaction steps with an excess of component a), followed by a chain extension step by adding component d), followed by the dispersing step by adding water to the prepolymer A) or transferring the prepolymer A) into an aqueous initial charge.

[0050] The dispersions according to the invention have solids contents (non-volatile fractions) of generally 25 to 65 wt.%, preferably 35 to 60 wt.%.

[0051] In the processes according to the invention, an organic solvent and / or a catalyst can be used in the preparation of the prepolymer A). Suitable catalysts for preparing the prepolymers A) or the dispersions according to the invention are, in principle, all those that catalyze the reaction of isocyanate groups with hydroxyl groups, such as tertiary amines, tin, zinc, zirconium, copper, and / or bismuth compounds, preferably triethylamine, ethyldiisopropylamine, dimethylcyclohexylamine, N-methylmorpholine, 1,4-diazabicyclo-[2,2,2]octane, tin dioctoate, or dibutyltin dilaurate. Salts of zinc, titanium, and molybdenum are also suitable. Suitable amounts are, for example, 0.002 to 1% by weight, preferably 0.01 to 0.1% by weight. The reaction can also be carried out without the use of a catalyst.

[0052] The dispersions according to the invention are generally prepared at 20 to 150 °C, preferably at 25 to 75 °C.

[0053] Component d) can be diluted with water and / or organic solvents in the process according to the invention. The optionally used solvent can then be removed by distillation. Production without the use of solvents is possible, but production in organic solvents is preferred.

[0054] The dispersion according to the invention generally contains less than 5% by weight, preferably less than 1% by weight and particularly preferably less than 0.5% by weight of organic solvents.

[0055] The preparation is preferably carried out in 3 to 50 wt.% (non-volatile portion of the acetone solution), particularly preferably in 5 to 25 wt.% acetone with subsequent distillative removal of the solvent after preparation of the dispersion or during the dispersion step.

[0056] Suitable solvents are, in principle, all solvents or solvent mixtures that do not react with the reaction components, such as N-butylpyrrolidone, butyl acetate, ethyl acetate, methoxypropyl acetate, diethylene glycol dimethyl ether, dioxane, dimethylformamide, xylene, toluene, solvent naphtha, cyclohexanone, methyl isobutyl ketone, diethyl ketone, methyl ethyl ketone, and acetone. Some of these solvents can subsequently be completely or partially removed by distillation. It is also possible to add further solvents after preparation of the dispersion according to the invention, for example, hydroxy-functional solvents such as butyl diglycol, methoxypropanol, or butyl glycol.

[0057] The dispersion according to the invention can be used for the production of glass fiber sizes.

[0058] The present invention therefore also relates to the use of the dispersion according to the invention for producing glass fiber sizes.

[0059] The present invention also relates to the glass fiber size containing at least one dispersion according to the invention.

[0060] The present invention also relates to glass fibers provided with a size obtainable using the dispersion according to the invention.

[0061] A glass fiber size generally contains the dispersion according to the invention, optionally at least one binder and optionally auxiliaries and additives.

[0062] To prepare the aqueous sizing composition, the present components are preferably mixed together one after the other in any order or simultaneously.

[0063] The preferably aqueous glass fiber sizing according to the invention may optionally contain further binders, for example polyurethane dispersions, polyacrylate dispersions, polyurethane-polyacrylate hybrid dispersions, polyvinyl ether or polyvinyl ester dispersions, polystyrene or polyacrylonitrile dispersions, also in combination with other blocked polyisocyanates and amino crosslinker resins such as melamine resins. In a preferred embodiment, no further binders are used apart from the dispersion according to the invention.

[0064] The glass fiber size according to the invention can contain the usual auxiliaries and additives, such as defoamers, thickeners, flow agents, dispersing agents, catalysts, anti-skinning agents, anti-settling agents, antioxidants, plasticizers, reactive diluents, emulsifiers, biocides, adhesion promoters, e.g. based on the known low- or high-molecular-weight silanes, lubricants, wetting agents, antistatic agents.

[0065] The known silane coupling agents used as coupling agents include, for example, 3-aminopropyltrimethoxysilane or triethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-glycidylpropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, or 3-methacryloxypropyltriethoxysilane. The concentration of the silane coupling agents in the glass fiber sizing according to the invention is preferably 0.05 to 2 wt.%, particularly preferably 0.15 to 0.85 wt.%, in each case based on the total sizing.

[0066] The glass fiber sizing according to the invention may contain one or more nonionic and / or ionic lubricants, which may be selected, for example, from the following groups of substances: polyalkylene glycol ethers of fatty alcohols or fatty amines, polyalkylene glycol ethers and glycerol esters of fatty acids with 12 to 18 carbon atoms, polyalkylene glycols, higher fatty acid amides with 12 to 18 carbon atoms of polyalkylene glycols and / or alkylene amines, quaternary nitrogen compounds, e.g., ethoxylated imidazolinium salts, mineral oils, and waxes. The lubricant(s) are preferably used in a total concentration of 0.05 to 1.5 wt.%, based on the total glass fiber sizing.

[0067] The glass fiber sizing according to the invention may contain one or more antistatic agents, such as lithium chloride, ammonium chloride, Cr(III) salts, organic titanium compounds, arylalkyl sulfates or sulfonates, aryl polyglycol ether sulfonates, or quaternary nitrogen compounds. The antistatic agents are preferably used in concentrations of 0.01 to 0.8 wt.%, based on the total glass fiber sizing.

[0068] In addition, the glass fiber size according to the invention may optionally contain further auxiliaries and additives known from the prior art, as described, for example, in KL Loewenstein "The Manufacturing Technology of Continuous Glass Fibres", Elsevier Scientific Publishing Corp., Amsterdam, London, New York, 1983.

[0069] The glass fiber sizing according to the invention can be produced using methods known per se. For example, approximately half of the total required water is placed in a suitable mixing container, and the binder, the hardener, and then the lubricant and, if desired, other conventional auxiliaries are added while stirring. The pH is then adjusted to preferably 5 to 7, and a hydrolyzate of an adhesion promoter, e.g., a trialkoxysilane, prepared according to the manufacturer's instructions (e.g., UCC, New York), is added. After a further stirring time of, for example, 15 minutes, the sizing is ready for use; if necessary, the pH is readjusted to 5 to 7.

[0070] The glass fiber sizing can be applied to the glass fiber using any method, for example using suitable devices such as spray or roller applicators.

[0071] Suitable glass fibers include the well-known glass types used in glass silk production, such as E-, A-, C-, and S-glass, as well as other well-known products from glass fiber manufacturers. E-glass fibers are preferred, as they are used for the production of continuous glass fibers due to their alkali-free nature, high tensile strength, and high modulus of elasticity, making them ideal for reinforcing plastics.

[0072] The manufacturing process, the sizing process and the post-processing of the glass fibers are known and are described, for example, in KL Loewenstein "The Manufacturing Technology of Continuous Glass Fibers", Elsevier Scientific Publishing Corp., Amsterdam, London, New York, 1983.

[0073] Typically, the glass fiber size is applied to the glass filaments drawn from spinnerets at high speed immediately after they solidify, i.e., before winding. However, it is also possible to size the fibers in an immersion bath following the spinning process. The sized glass fibers can be processed either wet or dry, for example, into chopped glass. The proportion of size, based on the sized glass fibers, is preferably 0.1 to 5.0 wt.%, more preferably 0.1 to 3.0 wt.%, and most preferably 0.3 to 1.5 wt.%.

[0074] In one variant, the sized glass fiber is dried in several stages: First, water and any solvent present are removed from the sizing by heat, convection, thermal radiation, and / or dehumidified air. Then, curing occurs with UV irradiation. Conventional, state-of-the-art lamps are used.

[0075] High- or medium-pressure mercury lamps are preferred, which can optionally be doped with elements such as gallium or iron. It may also be advantageous to combine several lamps in series, side by side, or in any three-dimensional arrangement. Furthermore, it may be advantageous to conduct UV irradiation at elevated temperatures, between 30 and 200 °C.

[0076] In another variant, the sized glass fiber is essentially dried physically: Water and any solvent present are removed from the sizing by heat, convection, thermal radiation, and / or dehumidified air, so that the acrylate groups contained essentially do not react during this stage but remain as acrylate groups. This variant is preferred.

[0077] The sized glass fibers can then be incorporated into matrix polymers. A variety of thermoplastics or thermosetting polymers can be used as matrix polymers. Examples of suitable thermoplastic polymers include: polyolefins such as polyethylene or polypropylene, polyvinyl chloride, polymers such as styrene / acrylonitrile copolymers, ABS, polymethacrylate, or polyoxymethylene, aromatic and / or aliphatic polyamides such as polyamide-6 or polyamide-6,6, polycondensates such as polycarbonate, polyethylene terephthalate, liquid-crystalline polyarylesters, polyarylene oxide, polysulfone, polyarylene sulfide, polyarylsulfone, polyethersulfone, polyarylether, or polyetherketone, or polyadducts such as polyurethanes.Examples of thermosetting polymers that can be cured include: epoxy resins, unsaturated polyester resins, vinyl resins, acrylate-functional resins, methacrylate-functional resins, phenolic resins, amine resins, polyurethane resins, polyisocyanurates, epoxy / isocyanurate combination resins, furan resins, cyanurate resins, and bismaleimide resins. Incorporation into the polymer matrix can be carried out using generally customary methods known to those skilled in the art (such as extrusion). In a preferred variant, the uncured matrix building blocks contain double-bond-containing groups such as ally groups, vinyl groups, acrylate groups, olefinic groups, or methacrylate groups. These are then preferably cured, for example, initiated by UV light, electron beams, heat, radical initiators, or a combination of the aforementioned methods. Curing can be carried out using generally customary methods known to those skilled in the art.

[0078] The present invention also relates to a process for producing glass fibre reinforced plastics, comprising at least the following steps: (A) applying the glass fiber size according to the invention to glass fibers to obtain sized glass fibers, (B) introducing the sized glass fibers into a plastic matrix, and (C) at least partially chemically reacting acrylate groups of the glass fiber size with the groups of the plastic matrix to form covalent bonds to obtain the glass fiber reinforced plastic.

[0079] Suitable plastics have already been mentioned above. Process parameters such as temperature, pressure, suitable equipment, etc. are known to those skilled in the art.

[0080] The present invention is explained using examples. Example Chemicals used:

[0081] Desmodur ®< Ultra N 3300 Isocyanurate based on hexamethylene diisocyanate, Covestro Deutschland AG, Leverkusen, DE

[0082] Unless otherwise stated, the other chemicals were purchased from Sigma-Aldrich Chemie GmbH, Taufkirchen, DE.

[0083] Unless otherwise stated, all percentages are by weight (wt%).

[0084] Unless otherwise stated, all analytical measurements were performed at a temperature of 23 °C.

[0085] The stated viscosities were determined by rotational viscometry according to DIN 53019-2008 at 23 °C using a rotational viscometer from Anton Paar Germany GmbH, Ostfildern, DE.

[0086] Unless explicitly stated otherwise, NCO contents were determined volumetrically according to DIN-EN ISO 11909-2007.

[0087] The stated particle sizes were determined by laser correlation spectroscopy (instrument: Malvern Zetasizer 1000, Malver Inst. Limited) after dilution of the sample with demineralized water.

[0088] The solids content was determined by heating a weighed sample to 120 °C. At constant weight, the solids content was calculated by reweighing the sample.

[0089] The presence of free NCO groups was checked by IR spectroscopy (band at 2260 cm -1< ).

[0090] As a storage test, 250 ml of the dispersion was filled and stored at both room temperature and 40 °C. A visual inspection was performed to determine whether sediment formed. Samples with sediment were considered unstable.

[0091] Unless otherwise stated, all molecular weights or molar masses mentioned in this application are defined by gel permeation chromatography (GPC) according to DIN EN ISO 13885-2:2021, in DMAc (N,N-dimethylacetamide) as eluent at 23 °C and calibrated with polystyrene standards.

[0092] The determination or definition of the OH numbers (hydroxyl numbers) is carried out according to DIN EN ISO 4629-2:2016. Inventive example

[0093] 344 g of Desmodur Ultra N 3300, 0.2 g of tin(II) chloride, 0.03 g of phenothiazine, and 0.59 g of butylhydroxytoluene in 135 g of acetone were placed in a standard stirred apparatus and heated to 50 °C. 161 g of 2-hydroxyethyl acrylate were then slowly added to the solution, and the mixture was allowed to react in boiling acetone for 3 hours. 128.3 g of methoxypolyethylene glycol with a number-average molecular weight of 750 g / mol and 7.0 g of 1,4-butanediol were then added, and the mixture was stirred while boiling until no isocyanate groups were detectable by IR spectroscopy. 783 g of deionized water were then added with vigorous stirring, and the acetone was distilled off under vacuum at 40 °C.

[0094] The resulting dispersion had the following properties: Solids content: approx. 44 wt.% PH value: approx. 3.4 viscosity approx. 108 mPa s Average particle size (LKS): 88 nm

[0095] The dispersion was stable for at least 4 weeks at room temperature and 40 °C. No phase separation occurred during this period. Example formulation of a glass fiber sizing

[0096] To test its general suitability in general glass fiber sizing, an example formulation was prepared according to the following table and stored at room temperature for 12 days. Example wording:

[0097] Input material Mass [g] Water (demineralized) 229,3 Dispersion from inventive example 15,0 Acetic acid (60 wt.% in water) 0,5 Polyvinylpyrrolidone 40000 (20 wt.% in water) 2,5 3-(Trimethoxysilyl)propyl methacrylate 1,3 3-(2-Aminoethylamino)propyltrimethoxysilane 1,5

[0098] Observation: No changes in viscosity or phase separation were observed over 12 days at room temperature.

Claims

1. Aqueous UV-curable dispersion at least comprising a reaction product formed from a) at least one polyisocyanate having an average isocyanate functionality of at least 2.2, of which preferably at least one polyisocyanate is an oligomeric polyisocyanate having urethane, biuret, allophanate, iminooxadiazinedione and / or isocyanurate structural units, b) at least one monohydroxy-functional compound containing acryloyl groups, c) at least one component that contains nonionically hydrophilizing groups and has at least one isocyanate-reactive group, d) at least one diol, triol, diamine and / or triamine, the at least one diol, triol, diamine and / or triamine preferably having a molecular weight of < 400 g / mol, characterized in that the reaction product has no ionogenic or ionically hydrophilizing groups.

2. Dispersion according to Claim 1, characterized in that the reaction product is obtained or is obtainable from the reaction of the following components: a) 35% to 75% by weight, particularly preferably 40% to 75% by weight, very particularly preferably 45% to 65% by weight, of component a), b) 10% to 50% by weight, particularly preferably 12% to 35% by weight, very particularly preferably 14% to 32% by weight, of component b), c) 5% to 40% by weight, particularly preferably 7% to 30% by weight, very particularly preferably 15% to 25% by weight, of component c), and d) 0.1% to 25% by weight, particularly preferably 0.1% to 9% by weight, very particularly preferably 0.1% to 5% by weight, of component d), wherein the percentages from a) to d) in each case add up to 100% by weight.

3. Dispersion according to Claim 1 or 2, characterized in that the polyisocyanate component a) consists to an extent of at least 40% by weight of oligomeric polyisocyanates based on hexamethylene diisocyanate that are liquid at room temperature and have isocyanurate, biuret, uretdione, carbodiimide and / or iminooxadiazinedione structural units and to an extent of not more than 60% by weight of isophorone diisocyanate, H6-2,4- or H6-2,6-tolylidene diisocyanate, hexamethylene 1,6-diisocyanate, 4,4'-diisocyanatodicyclohexylmethane and / or 2,4'-diisocyanatodicyclohexylmethane and / or 2,2'-diisocyanatodicyclohexylmethane and / or 2,4- or 2,6-tolylidene diisocyanate or reaction products thereof with trimethylolpropane, butanediol, ethylene glycol, diethylene glycol, propylene glycol or neopentyl glycol.

4. Dispersion according to any of Claims 1 to 3, characterized in that the polyisocyanate component a) consists to an extent of at least 70% by weight of oligomeric polyisocyanates based on hexamethylene diisocyanate and having biuret, iminooxadiazinedione and / or isocyanurate structural units and to an extent of not more than 30% by weight of isophorone diisocyanate, 4,4'-diisocyanatodicyclohexylmethane and / or 2,4'-diisocyanatodicyclohexylmethane and / or 2,2'-diisocyanatodicyclohexylmethane and / or 2,4- or 2,6-tolylidene diisocyanate.

5. Dispersion according to any of Claims 1 to 4, characterized in that it contains 0.5% to 40% by weight of component e).

6. Dispersion according to any of Claims 1 to 5, characterized in that at least one monohydroxy-functional polyalkylene oxide polyether having a molecular weight of 500 to 1100 g / mol is used as component c).

7. Dispersion according to any of Claims 1 to 6, characterized in that component d) is used in amounts such that the degree of chain elongation is 100 to 200%.

8. Dispersion according to any of Claims 1 to 7, characterized in that it has an acid value of below 50 mg KOH / g polymer, preferably below 20 mg KOH / g polymer, particularly preferably below 10 mg KOH / g polymer, and particularly preferably below 5 mg KOH / g polymer (measurement according to EN ISO 660 (2009 version)).

9. Dispersion according to any of Claims 1 to 8, characterized in that component d) is selected from the group consisting of butanediol, hexanediol, neopentyl glycol, ethylene glycol, propylene glycol, ethylenediamine, isophoronediamine, hydrazine (hydrate), hexamethylene-1,6-diamine, diethylenetriamine and / or polymer diols, wherein the polymer diols preferably have a number-average molecular weight in the range from 700 to 2200 g / mol, determined by gel-permeation chromatography (GPC) in accordance with DIN EN ISO 13885-2:2021 in N,N-dimethylacetamide as eluent at 23°C, with calibration using polystyrene standards, and that component d) is particularly preferably selected from the group consisting of butanediol, hexanediol, neopentyl glycol, ethylene glycol, propylene glycol, ethylenediamine, isophoronediamine, hydrazine (hydrate), hexamethylene-1,6-diamine and / or diethylenetriamine.

10. Process for producing the dispersion according to any of Claims 1 to 9, characterized in that an isocyanate-functional prepolymer A) is obtained by reacting components a), b) and c) in one or more reaction steps with an excess of component a), followed by a chain-lengthening step through addition of component d), followed by the dispersing step through addition of water to form the prepolymer A) or transfer of the prepolymer A) to an aqueous receiver vessel.

11. Process for producing the dispersion according to any of Claims 1 to 9, characterized in that an isocyanate-functional prepolymer A) is obtained by reacting components b) and c) in one or more reaction steps with an excess of component a), followed by the dispersing step through addition of water to form the prepolymer A) or transfer of the prepolymer A) to an aqueous receiver vessel, followed by a chain-lengthening step through addition of component d).

12. Use of the dispersion according to any of Claims 1 to 9 for producing glass fibre sizings.

13. Glass fibre sizing at least comprising a dispersion according to any of Claims 1 to 9.

14. Glass fibre provided with a sizing obtainable using a dispersion according to any of Claims 1 to 9.

15. Process for producing glass-fibre-reinforced plastics, comprising at least the following steps: (A) applying a glass fibre sizing according to Claim 13 to glass fibres to obtain sizing-treated glass fibres, (B) introducing the sizing-treated glass fibres into a plastic matrix, and (C) at least partially chemically reacting acrylate groups of the glass fibre sizing with the groups of the plastic matrix with the formation of covalent bonds so as to obtain the glass-fibre-reinforced plastic.

16. Glass-fibre-reinforced plastic comprising glass fibres according to Claim 14 or glass fibres that have undergone sizing treatment with a glass fibre sizing according to Claim 13.