Two-component polyurethane composition

Abstract

The present invention relates to a two-component polyurethane composition consisting of a polyol component and a polyisocyanate component, wherein the polyol component comprises at least one reaction product of epoxidized vegetable oils with monofunctional C1-8-alcohols A1-1 and / or at least one reaction product of epoxidized fatty acid esters of monofunctional C1-8-alcohols with aliphatic alcohols A1-2, preferably at least one polybutadiene polyol A2 and at least one alkoxylated branched alkylene diamine with 5-10 atoms A3. The polyurethane composition according to the invention has high strength and an open time of more than 10 minutes.

Description

[0001] TWO-COMPONENT POLYURETHANE COMPOSITION

[0002] Technical area

[0003] The invention relates to the field of two-component polyurethane compositions and their use, in particular as adhesives, potting compounds or infusion resins, in particular for the production of composite materials.

[0004] State of the art

[0005] Two-component polyurethane adhesives based on polyols and polyisocyanates have been in use for a long time. Two-component polyurethane adhesives have the advantage of curing quickly after mixing and can therefore absorb and transfer higher forces within a short time. For use as structural adhesives, such adhesives must meet high strength requirements, as they represent elements of load-bearing structures. High strength requirements are also placed on them for use as potting compounds or infusion resins.

[0006] WO 2018228936 discloses two-component polyurethane compositions containing N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine for use as adhesives, potting compounds, or infusion resins. However, these compositions have the disadvantage of a short open time of less than 5 minutes and are therefore not very suitable as structural adhesives.

[0007] There is a particular demand for adhesives, potting compounds, and infusion resins that exhibit / ensure high strengths for structural bonding over the widest possible temperature range, especially from -50°C to over +130°C, combined with a low dependence of strength on temperature. Furthermore, the compositions should have an open time of more than 10 minutes, which enables their use as adhesives for larger structures in the industrial and construction sectors.

[0008] Description of the invention

[0009] The object of the present invention is therefore to provide a two-component polyurethane composition that has high strength, an open time of more than 10 minutes, and only a weak dependence of the mechanical properties, in particular the strength, on temperature, especially in the range from -40°C to +100°C. Surprisingly, this object is achieved with the two-component polyurethane composition according to the invention. The composition has high tensile strength and high elastic moduli with an open time sufficiently long for processing and application, and only a weak dependence of the mechanical properties, in particular the tensile strength and the elastic moduli, on temperature.

[0010] Furthermore, it was surprisingly found that, due to the presence of the polybutadiene polyol A2, the compositions according to the invention exhibit a first glass transition temperature (Tg1) at low temperatures below -70°C and a second dominant glass transition temperature (Tg2) at temperatures above +100°C, in particular above +140°C. This has the advantage of temperature-independent mechanical properties over a broad and application-oriented temperature range. After heating to a temperature higher than Tg1, the material exhibits viscoelastic properties and thus a structurally determined, intrinsic toughness modification.

[0011] Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims.

[0012] Ways to implement the invention

[0013] The present invention relates to a two-component polyurethane composition consisting of a polyol component K1 and a polyisocyanate component K2; wherein the polyol component K1

[0014] -at least one reaction product of epoxidized vegetable oils having a C fatty acid content of more than 50 wt.%, in particular more than 60 wt.%, based on the total amount of fatty acids, with monofunctional Ci-s alcohols A1-1; and / or

[0015] -at least one reaction product of epoxidized fatty acid esters of monofunctional Ci-s-alcohols, in particular methanol, with aliphatic alcohols having an OH functionality in the range from 2 to 5, in particular glycerol, the epoxidized fatty acid esters being based as fatty acid components on fatty acid mixtures which have a content of C fatty acids, in particular unsaturated C fatty acids, of at least 50% by weight, based on the total fatty acid mixture; and -preferably at least one polybutadiene polyol having an OH functionality in the range from 2.1 to 2.9, in particular 2.3 to 2.7, and having an average molecular weight in the range from 2000 to 4000 g / mol, in particular 2500 to 3000 g / mol, and an OH number of 40 - 100 mg KOH / g A2; and -at least one alkoxylated branched alkylenediamine having 5 - 10 C atoms, in particular 6 - 9 C atoms, with an OH number of 450 - 800 mg KOH / g A3; and wherein the polyisocyanate component K2 comprises at least one aromatic polyisocyanate B1.

[0016] The ratio of all NCO groups of the aromatic polyisocyanates B1 : all OH groups of the polyol component K1 is 0.9 : 1 - 1.2 : 1, in particular 1.0 : 1 - 1.1 : 1.

[0017] In this document, the prefix “poly” in substance names such as “polyol”, “polyisocyanate”, “polyether” or “polyamine” indicates that the respective substance formally contains more than one of the functional groups mentioned in its name per molecule.

[0018] In this document, "molecular weight" refers to the molar mass (in grams per mole) of a molecule. "Mean molecular weight" refers to the number-average molecular weight M n a polydisperse mixture of oligomeric or polymeric molecules, which is usually determined by GPC against polystyrene as a standard.

[0019] A “primary hydroxyl group” is an OH group that is bonded to a C atom with two hydrogens.

[0020] In this document, “open time” refers to the time within which the parts to be bonded must be joined after the components have been mixed.

[0021] In this document, the term “strength” refers to the strength of the cured adhesive, whereby strength refers in particular to the tensile strength and the modulus of elasticity (E-modulus), especially in the elongation range 0.05 to 0.25%.

[0022] In this document, “room temperature” is defined as 23°C.

[0023] The glass transition temperature (hereinafter abbreviated to Tg) is determined in this document using the dynamic mechanical thermal analysis (DMTA) method, as described in the examples section. The polyol component K1 comprises:

[0024] -at least one reaction product of epoxidized vegetable oils having a cis-fatty acid content of more than 50 wt.%, in particular more than 60 wt.%, based on the total amount of fatty acids, with monofunctional cis-s-alcohols A1-1; and / or

[0025] -at least one reaction product of epoxidized fatty acid esters of monofunctional Ci-s-alcohols, in particular methanol, with aliphatic alcohols having an OH functionality in the range from 2 to 5, in particular glycerol, the epoxidized fatty acid esters being based as fatty acid component on fatty acid mixtures which have a content of C-fatty acids, in particular unsaturated C-fatty acids, of at least 50% by weight, based on the total fatty acid mixture A1-2.

[0026] Preferably, these are reaction products A1-1 of epoxidized vegetable oils having a C fatty acid content of more than 60 wt.%, in particular more than 65 wt.%, based on the total amount of fatty acids, with monofunctional Ci-s alcohols.

[0027] Preferably, A1-1 comprises vegetable oils selected from the list consisting of sunflower oil, rapeseed oil and castor oil, in particular sunflower oil and / or rapeseed oil.

[0028] The reaction products A1-1 preferably have an OH number of 100 - 350, in particular 200 - 330, in particular 260 - 310 mg KOH / g.

[0029] Furthermore, it is preferred if the reaction products A1-1 have an OH functionality of 2 - 3.

[0030] In this document, the term “vegetable oil” refers in particular to vegetable oil as described in Römpp online, version 4.0, Thieme Verlag, accessed on 23 August 2023.

[0031] The aforementioned reaction products A1-2 are formed, for example, in the case of an alkyl oleate as follows. This ester contains a C=C double bond in the 9- and 10-position of the fatty acid chain. This double bond is susceptible to epoxidation, yielding the corresponding epoxidized alkyl oleate. This ester is then reacted with aliphatic alcohols with an OH functionality in the range of 2 to 5, for example, glycerol, to form a corresponding polyol. This reaction thus proceeds by ring opening and transesterification. The ring opening and transesterification reactions preferably occur with glycerol.

[0032] Preferred are reaction products A1-2, which have a ratio of epoxidized fatty acid ester to alcohol used for the reaction of 1 : 1 to 2 : 1.

[0033] The reaction products A1-2 preferably have an OH number of 200 - 350, in particular 250 - 330, in particular 280 - 320 mg KOH / g.

[0034] The reaction products A1-2 preferably have an OH functionality of 2 - 3.

[0035] It is preferred if the epoxidized fatty acid esters are based on fatty acid mixtures as fatty acid component which have a content of cis fatty acids, in particular unsaturated cis fatty acids, of at least 60 wt.%, of at least 70 wt.%, of at least 80 wt.%, in particular of at least 85 wt.%, based on the total fatty acid mixture.

[0036] Preferably, the content of cis-fatty acids in these fatty acid mixtures, based on the total fatty acid mixture, is at least 70% by weight, at least 80% by weight, in particular at least 85% by weight.

[0037] Preferably, the content of oleic acid and linoleic acid in these fatty acid mixtures, based on the total fatty acid mixture, is at least 60% by weight, at least 70% by weight, in particular at least 80% by weight.

[0038] The epoxidized fatty acid esters are particularly preferably based on fatty acid mixtures from sunflower oil or rapeseed oil as the fat component.

[0039] Furthermore, it is advantageous if the aliphatic alcohols used for the reaction with the epoxidized fatty acid esters are selected from the group consisting of ethylene glycol, propylene glycol, glycerol, trimethylolpropane, and pentaerythritol. Glycerol is particularly preferred.

[0040] The polyol component K1 particularly preferably comprises at least one reaction product A1-1 and at least one reaction product A1-2, the weight ratio (A1-1 / A1-2) being from 1:3 to 3:1, in particular 1:2 to 2:1, particularly preferably from 1:1 to 2:1. This enables compositions which achieve high values ​​for the Tg (2nd Tg) in the range above 130°C and have high values ​​for the tensile strength. The polyol component K1 preferably comprises at least one polybutadiene polyol with an OH functionality in the range from 2.1 to 2.9, in particular 2.3 to 2.7, and with an average molecular weight in the range from 2000 to 4000 g / mol, in particular 2500 to 3000 g / mol, and an OH number of 40 - 100 mg KOH / g A2.

[0041] This is advantageous in that, due to the presence of the polybutadiene polyol A2, the compositions according to the invention exhibit a first glass transition temperature (Tg1) at low temperatures below -70°C and a second dominant glass transition temperature (Tg2) at temperatures above +100°C, in particular above +140°C. This has the advantage of consistent mechanical properties over a broad and application-relevant temperature range. After heating to a temperature higher than Tg1, the material exhibits viscoelastic properties and thus a structurally determined, intrinsic toughness modification. This can be seen, for example, in Table 1 when comparing E7 and E8 with E3 and E4.

[0042] Such polybutadiene polyols are particularly obtainable by the polymerization of 1,3-butadiene and allyl alcohol in a suitable ratio or by the oxidation of suitable hydroxy-terminated (HT) polybutadienes.

[0043] Suitable polybutadiene polyols are in particular polybutadiene polyols which contain structural elements of the formula (I) and optionally structural elements of the formulas (II) and (III).

[0044] ___ / = V___ ei)

[0045] Preferred polybutadiene polyols contain

[0046] 40 to 80%, in particular 55 to 65% of the structural element of formula (I),

[0047] 0 to 30%, in particular 15 to 25%, of the structural element of formula (II),

[0048] 0 to 30%, in particular 15 to 25%, of the structural element of formula (III).

[0049] Particularly suitable polybutadiene polyols are available, for example, from Cray Valley under the trade name Poly bd® R-45HTLO or Poly bd® R-45M, or from Evonik under the trade name Polyvest HT. The polyol component K1 comprises at least one alkoxylated branched alkylenediamine having 5-10 C atoms, in particular 6-9 C atoms, with an OH number of 450-800 mg KOH / g A3. The alkoxylated alkylenediamine A3 preferably has an OH number of 500-750, in particular 550-700, in particular 600-660 mg KOH / g. The number of 5-10 C atoms, in particular 6-9 C atoms, refers to the C atoms of the branched alkylenediamine before alkoxylation.

[0050] Surprisingly, it was found that the aforementioned alkoxylated branched alkylenediamine A3 leads to a significant increase in open time. This is evident, for example, in Table 1 when comparing E1-E8 with Ref1-Ref8.

[0051] Preferably, these are alkylenediamines having 5-10 C atoms, in particular 6-9 C atoms, selected from the list consisting of 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine and 2-methyl-1,5-pentamethylenediamine, particularly preferably 2-methyl-1,5-pentamethylenediamine.

[0052] To prepare the alkoxylated alkylenediamines, preference is given to using ethylene oxide and / or 1,2-propylene oxide, in particular 1,2-propylene oxide.

[0053] Preferred alkoxylated branched alkylenediamines are selected from the list consisting of N,N,N',N'-tetrakis(2-hydroxypropyl)-2-methyl-pentamethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)-2,2,4-trimethylhexamethylenediamine and N,N,N',N'-tetrakis(2-hydroxypropyl)-2,4,4-trimethylhexamethylenediamine.

[0054] Particularly preferred is N,N,N',N'-tetrakis(2-hydroxypropyl)-2-methylpentamethylenediamine, which is commercially available, for example, as Propoxylated Dytek® A from Dytek / Specialty Intermediates INVISTA.

[0055] The present polyisocyanate component K2 comprises at least one aromatic polyisocyanate B1.

[0056] Suitable aromatic polyisocyanates B1 are in particular monomeric di- or triisocyanates, as well as oligomers, polymers and derivatives of monomeric di- or triisocyanates, as well as any mixtures thereof.

[0057] Suitable aromatic monomeric di- or triisocyanates are in particular 2,4- and 2,6-tolylene diisocyanate and any mixtures of these isomers (TDI), 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate and any mixtures of these isomers (MDI), 1,3- and 1,4-phenylene diisocyanate, 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene-1,5-diisocyanate (NDI), 3,3'-dimethyl-4,4'-diisocyanatodiphenyl (TODI), dianisiside diisocyanate (DADI), 1,3,5-tris-(isocyanatomethyl)benzene, tris-(4-isocyanatophenyl)methane and tris-(4-isocyanatophenyl)thiophosphate. Preferred aromatic monomeric di- or triisocyanates are derived from MDI and / or TDI, in particular from MDI.

[0058] Suitable oligomers, polymers, and derivatives of the above-mentioned monomeric di- and triisocyanates are, in particular, derived from MDI and TDI. Of these, commercially available types, TDI oligomers such as Desmodur® IL (from Bayer), are particularly suitable. Also suitable are forms of MDI which are liquid at room temperature (so-called “modified MDI”), which are mixtures of MDI with MDI derivatives, such as in particular MDI carbodiimides or MDI uretonimines, known under trade names such as Desmodur® CD, Desmodur® PF, Desmodur® PC (all from Covestro AG), as well as mixtures of MDI and MDI homologues (polymeric MDI or PMDI), available under trade names such as Desmodur® VL, Desmodur® VL50, Desmodur® VL R10, Desmodur® VL R20, Desmodur® VH 20 N and Desmodur® VKS 20F (all from Covestro AG), Isonate® M 309, Voranate® M 229 and Voranate® M 580 (all from Dow) or Lupranat® M 10 R (from BASF).In practice, the aforementioned oligomeric polyisocyanates usually represent mixtures of substances with different degrees of oligomerization and / or chemical structures. They preferably have an average NCO functionality of 2.1 to 4.0, preferably 2.1 to 3.0, in particular 2.1 to 2.6.

[0059] Preferred aromatic polyisocyanates B1 are monomeric MDI or oligomers, polymers and derivatives derived from MDI, in particular with an average NCO functionality of 2.0 to 4.0, preferably 2.0 to 3.0, in particular 2.1 to 2.6.

[0060] Particularly advantageous are oligomers, polymers and derivatives derived from MDI, in particular polymers derived from MDI, in particular with an average NCO functionality of 2.1 to 2.6.

[0061] When it comes to oligomers, polymers, and derivatives derived from MDI with an average NCO functionality of 2.4 to 2.6, this can be advantageous in that it results in high open time values. This is evident, for example, in Table 1 when comparing E1 with E2.

[0062] In the case of MDI-derived oligomers, polymers, and derivatives with an average NCO functionality of 2.1 to 2.3, this can be advantageous in that higher values ​​for tensile strength, elongation at break, and elastic moduli are obtained. This can be seen, for example, in Table 1 when comparing E2 with E1.

[0063] Also particularly advantageous are MDI monomers, in particular 4,4'-, 2,4'-, and 2,2'-diphenylmethane diisocyanate, and any mixtures of these isomers (MDI), especially mixtures of 4,4'- and 2,4'-diphenylmethane diisocyanate, especially with an NCO content of 31.0 - 34.0 wt.%. The increased content of 2,4'-MDI is advantageous in that it results in particularly long open times and very high values ​​for tensile strength and elastic moduli. This can be seen, for example, in Table 1 when comparing E3 and E4 with E1 and E2.

[0064] A mixture of 4,4'- and 2,4'-diphenylmethane diisocyanate, particularly in a 4,4'- to 2,4'-diphenylmethane diisocyanate ratio of 1:1 - 2:1, preferably with an NCO content of 31.0 - 34.0 wt.%, is advantageous in that it results in long open times and very high values ​​for tensile strength and elastic moduli. This can be seen, for example, in Table 1 when comparing E3 with E1, E2, and E4.

[0065] A mixture of 4,4'- and 2,4'-diphenylmethane diisocyanate, particularly in a 4,4'- to 2,4'-diphenylmethane diisocyanate ratio of 1:1.5 - 1:2.0, preferably with an NCO content of 31.0 - 34.0 wt.%, is advantageous in that it results in particularly long open times and high values ​​for tensile strength and elastic moduli. This can be seen, for example, in Table 1 when comparing E4 with E1, E2, and E3.

[0066] It is further advantageous if the sum of the NCO groups which do not originate from B1 is <5%, in particular <2%, particularly preferably <1%, most preferably <0.5%, based on the sum of all NCO groups of the two-component polyurethane composition.

[0067] The proportion of aromatic polyisocyanate B1 is preferably >90% by weight, in particular >95% by weight, particularly preferably >99% by weight, based on the total weight of polyisocyanate component K2. The proportion of aromatic polyisocyanate B1 is preferably >90% by weight, in particular >95% by weight, particularly preferably >99% by weight, based on the total weight of polyisocyanate component K2.

[0068] Preferably, the ratio of the OH groups of (A1-1 + A1-2 + A2) / (A3) is 1.1-10, preferably 1.2-3.5, particularly preferably 1.3-1.75. The ratio described above refers to the molar ratio of the groups mentioned.

[0069] It is further preferred if the ratio of the OH groups of (A1-1 + A1-2) / (A3) is 1.1-10, preferably 1.2-3.5, particularly preferably 1.3-1.75. The ratio described above refers to the molar ratio of the groups mentioned.

[0070] It is further advantageous if the ratio of the OH groups of (A1-1 + A1-2) / (A2) is 5-30, preferably 10-25, particularly preferably 15-20. The ratio described above is understood to mean the molar ratio of the groups mentioned.

[0071] It is further advantageous if the ratio of the OH groups of (A3) / (A2) is 5-25, preferably 7.5-20, particularly preferably 10-15. The ratio described above is understood to mean the molar ratio of the groups mentioned.

[0072] The ratio of all NCO groups of the aromatic polyisocyanates B1 : all OH groups of the polyol component K1 is = 0.9 : 1 - 1.2 : 1, in particular 1.0 : 1 - 1.1 : 1.

[0073] Preferably, the ratio of all NCO groups of the aromatic polyisocyanates B1 : all OH groups of the sum of (A1-1 + A1-2 + A2 + A3) = 0.9 : 1 - 1.2 : 1 , in particular 1.0 : 1 - 1.1 : 1 .

[0074] The ratios described above refer to the molar ratio of the groups mentioned.

[0075] Furthermore, it may be preferred if, in the two-component polyurethane composition, the sum of all OH groups of (A1-1 + A1-2 + A2 + A3) is >60%, >70%, in particular >80%, particularly preferably >90%, most preferably >95%, of the sum of all NCO-reactive groups, in particular OH groups, of the two-component polyurethane composition.

[0076] Preferably, the two-component polyurethane composition is substantially free of NCO-reactive groups, in particular OH groups, which do not originate from (A1-1 + A1-2 + A2 + A3). The term "substantially free" in this case means that the sum of the NCO-reactive groups, in particular OH groups, which do not originate from (A1-1 + A1-2 + A2 + A3), is <15%, in particular <10%, particularly preferably <5%, most preferably <2%, based on the sum of all NCO-reactive groups, in particular OH groups, of the two-component polyurethane composition.

[0077] Furthermore, the two-component polyurethane composition can contain catalysts that accelerate the reaction of hydroxyl groups with isocyanate groups, in particular tin, zinc, zirconium, and bismuth organometallic catalysts, for example dibutyltin dilaurate, or tertiary amines, amidines, or guanidines, for example 1,4-diazabicyclo[2.2.2]octane (DABCO) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). To achieve heat activation, the tertiary amines, amidines, or guanidines can reversibly form a salt or complex with phenol or carboxylic acids, especially phenolic or other aromatic carboxylic acids, which decomposes upon increasing temperature, thus enabling the catalyst to function.

[0078] In addition to those already mentioned, the two-component polyurethane composition may contain other components familiar to those skilled in the art from two-component polyurethane chemistry. These may be present in only one component or in both.

[0079] Preferred further components are inorganic and organic fillers, such as natural, ground or precipitated calcium carbonates, which may be coated with fatty acids, in particular stearic acid, barite (barite), talc, quartz flour, quartz sand, dolomite, wollastonite, kaolins, calcined kaolins, mica (potassium aluminum silicate), molecular sieves, aluminum oxides, aluminum hydroxides, magnesium hydroxide, silicas including highly dispersed silicas from pyrolysis processes, industrially produced carbon blacks, graphite, metal powders such as aluminum, copper, iron, silver or steel, PVC powder or hollow spheres.

[0080] The addition of fillers is advantageous, especially when the polyurethane composition is an adhesive, in that it increases the strength of the cured polyurethane composition.

[0081] It may be advantageous if the polyurethane composition contains at least one filler selected from the group consisting of calcium carbonate, kaolin, barite, talc, quartz flour, dolomite, wollastonite, kaolin, calcined kaolin and mica.

[0082] Further components that may be present include, in particular, solvents, plasticizers and / or extenders, pigments, rheology modifiers such as, in particular, amorphous hydrophobic silicas, drying agents such as, in particular, zeolites, adhesion promoters such as, in particular, trialkoxysilanes, stabilizers against oxidation, heat, light and UV radiation, flame-retardant substances, and surface-active substances, in particular wetting agents and defoamers.

[0083] Components K1 and K2 are advantageously formulated such that the volume ratio of components K1 and K2 is between 1:3 and 3:1, in particular between 1:2 and 2:1. This ratio is particularly preferably approximately 1:1.

[0084] A preferred two-component polyurethane composition consists of a polyol component K1, which:

[0085] - 70 to 95% by weight, preferably 80 to 95% by weight, in particular 85 to 95% by weight, of the sum (A1-1 + A1-2 + A2 + A3); and

[0086] - 5 to 30% by weight, preferably 5 to 20% by weight, in particular 5 to 10% by weight, of fillers, in particular fillers selected from the group consisting of calcium carbonate, kaolin, barite, talc, quartz flour, dolomite, wollastonite, kaolin, calcined kaolin, and mica, particularly preferably calcium carbonate and rheology modifiers such as, in particular, hydrophobic amorphous silicas; and

[0087] - 0 to 5% by weight, preferably 1 to 3% by weight, of catalysts for accelerating the reaction of hydroxyl groups with isocyanate groups and drying agents (in particular zeolites); based on the total weight of the polyol component K1, contains, in particular consists thereof, and of a polyisocyanate component K2 which: - has a proportion of the aromatic polyisocyanate B1 >90% by weight, in particular >95% by weight, particularly preferably >99% by weight, based on the total weight of the polyisocyanate component K2.

[0088] Such a composition is particularly suitable as a casting compound.

[0089] Another preferred two-component polyurethane composition consists of a polyol component K1, which:

[0090] - 30 to 70% by weight, preferably 40 to 60% by weight, in particular 45 to 55% by weight, of the sum (A1-1 + A1-2 + A2 + A3); and

[0091] - 20 to 60% by weight, preferably 30 to 50% by weight, in particular 35 to 45% by weight, of fillers, in particular fillers selected from the group consisting of calcium carbonate, kaolin, barite, talc, quartz flour, dolomite, wollastonite, kaolin, calcined kaolin, and mica, particularly preferably calcium carbonate and rheology modifiers such as, in particular, hydrophobic amorphous silicas; and

[0092] - 0 to 5% by weight, preferably 1 to 4% by weight, particularly preferably 2 to 4% by weight, of catalysts for accelerating the reaction of hydroxyl groups with isocyanate groups;

[0093] - 0 to 5% by weight, preferably 0.5 to 3% by weight, particularly preferably 1 to 2% by weight, of drying agents (particularly zeolites); based on the total weight of the polyol component K1, contains, in particular consists of, and of a polyisocyanate component K2, which:

[0094] -has a proportion of the aromatic polyisocyanate B1 >90 wt.%, in particular >95 wt.%, particularly preferably >99 wt.%, based on the total weight of the polyisocyanate component K2.

[0095] Such a composition is particularly suitable as an adhesive.

[0096] Another preferred two-component polyurethane composition consists of a polyol component K1, which:

[0097] - 90 to 100% by weight, preferably 95 to 97% by weight, of the sum (A1-1 + A1-2 + A2 + A3); and

[0098] - 0 to 5% by weight, preferably 0 to 2% by weight, in particular 0 to 0.5% by weight, particularly preferably less than 0.1% by weight, most preferably no fillers, in particular fillers selected from the group consisting of calcium carbonate, kaolin, barite, talc, quartz flour, dolomite, wollastonite, kaolin, calcined kaolin, and mica, particularly preferably calcium carbonate and rheology modifiers such as in particular hydrophobic amorphous silicas; and

[0099] - 0 to 5% by weight, preferably 0 to 2% by weight, particularly preferably 0 to 0.5% by weight, particularly preferably 0 to 0.3% by weight, of catalysts for accelerating the reaction of hydroxyl groups with isocyanate groups;

[0100] - 0 to 5% by weight, preferably 0.5 to 3% by weight, particularly preferably 1 to 2% by weight, of drying agents (particularly zeolites); based on the total weight of the polyol component K1, contains, in particular consists of, and of a polyisocyanate component K2, which:

[0101] -has a proportion of the aromatic polyisocyanate B1 >90 wt.%, in particular >95 wt.%, particularly preferably >99 wt.%, based on the total weight of the polyisocyanate component K2.

[0102] Such a composition is particularly suitable as an infusion resin.

[0103] The two components are manufactured separately and, at least for the second component, preferably in the absence of moisture. Each component is typically stored in its own container. The other constituents of the polyurethane composition can be present as part of the first or second component, with other constituents reactive towards isocyanate groups preferably being a part of the first component. A suitable container for storing the respective component is, in particular, a drum, a hobbock, a bag, a bucket, a can, a cartridge or a tube. Both components are storage-stable, which means that they can be stored for several months up to a year or longer before use without their respective properties changing to an extent relevant to their use.

[0104] The two components are stored separately from each other before mixing the composition and are only mixed together during or immediately before use. They are advantageously contained in a package consisting of two separate chambers. In a further aspect, the invention encompasses a package consisting of two separate chambers, each containing the first component and the second component of the composition, respectively.

[0105] Mixing is typically performed using static mixers or dynamic mixers. During mixing, care must be taken to ensure that the two components are mixed as homogeneously as possible. If the two components are incompletely mixed, local deviations from the optimal mixing ratio will occur, which can result in a deterioration in the mechanical properties.

[0106] When the first component comes into contact with the isocyanate groups of the second component, curing begins through a chemical reaction. The hydroxyl groups present and any other substances reactive toward isocyanate groups, as well as water from moisture, react with the isocyanate groups. As a result of these reactions, the polyurethane composition cures into a solid material. This process is also known as crosslinking.

[0107] A further subject of the invention is therefore also a cured polyurethane composition obtained from the curing of the polyurethane composition as described in the present document.

[0108] The described two-component polyurethane composition can be advantageously used as a structural adhesive, as a potting compound or as an infusion resin.

[0109] The invention thus also relates to a method for bonding a first substrate to a second substrate, which comprises the steps:

[0110] - Mixing the previously described polyol component K1 and polyisocyanate component K2,

[0111] - Applying the mixed polyurethane composition to at least one of the substrate surfaces to be bonded,

[0112] - Joining the substrates to be bonded within the open time,

[0113] - Curing of the polyurethane composition.

[0114] The two substrates can be made of the same or different materials.

[0115] The invention thus further relates to a method for filling joints and gaps between two substrates, which comprises the steps of: - mixing the previously described polyol component K1 and polyisocyanate component K2,

[0116] - Applying the mixed polyurethane composition into the joint or gap,

[0117] - Curing of the polyurethane composition.

[0118] In these processes for bonding or filling joints and gaps, suitable substrates are particularly

[0119] - glass, glass ceramics, glass mineral fibre mats, glass fibre fabrics;

[0120] - Metals and alloys, such as aluminum, iron, steel, as well as surface-treated metals and alloys, such as galvanized or chrome-plated metals;

[0121] - coated and painted substrates, such as powder-coated metals or alloys and painted sheets;

[0122] - Plastics, such as polyvinyl chloride (rigid and soft PVC), acrylonitrile-butadiene-styrene copolymers (ABS), polycarbonate (PC), polyamide (PA), poly(methyl methacrylate) (PMMA), polyester, epoxy resins, in particular epoxy-based thermosets, polyurethanes (PUR), polyoxymethylene (POM), polyolefins (PO), polyethylene (PE) or polypropylene (PP), ethylene / propylene copolymers (EPM) and ethylene / propylene / diene terpolymers (EPDM), whereby the plastics can preferably be surface-treated by means of plasma, corona or flames;

[0123] - Fiber-reinforced plastics, such as carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GRP) and sheet molding compounds (SMC);

[0124] - wood, with resins, for example phenolic, melamine or epoxy resins, bonded wood materials, resin-textile composites and other so-called polymer composites; and

[0125] - Concrete, mortar, bricks, plaster and natural stones such as granite, limestone, quarry stone or marble.

[0126] In these processes, one or both substrates are preferably a metal or a glass ceramic or a glass or a glass fiber reinforced plastic or a carbon fiber reinforced plastic or an epoxy-based thermoset.

[0127] If necessary, the substrates can be pretreated before applying the composition. Such pretreatments include, in particular, physical and / or chemical cleaning processes, as well as the application of an adhesion promoter, an adhesion promoter solution, or a primer. The described bonding process results in an article in which the composition bonds two substrates together.

[0128] This article is in particular a sandwich element of a lightweight structure, a building, for example a bridge, an industrial good or a consumer good, in particular a window, a rotor blade of a wind turbine or a means of transport, in particular a vehicle, preferably an automobile, a bus, a lorry, a rail vehicle or a ship, as well as an aircraft or a helicopter; or an attachment of such an article.

[0129] The described two-component polyurethane composition is characterized, among other things, by its weak temperature dependence of mechanical properties, particularly tensile strength and elastic modulus. These properties make it particularly suitable as a structural adhesive for bondings subject to outdoor exposure to ambient temperatures.

[0130] A further object of the invention is therefore the use of the described polyurethane composition as a structural adhesive for bonding two substrates.

[0131] The described polyurethane composition can also be used advantageously as a casting compound, in particular as a casting compound for filling gaps and joints, for repair purposes, as a ballast leveling compound or for protecting electronic components.

[0132] The polyurethane composition is further preferably used as a potting compound, in particular as an electrical potting compound. In a further aspect, the invention therefore encompasses the use of a two-component polyurethane composition as a potting compound, in particular as an electrical potting compound.

[0133] Typical examples of applications of the polyurethane compositions according to the invention can be found in the field of electrical encapsulation compounds.

[0134] In a further aspect, the invention therefore comprises a method for filling joints and gaps in a substrate comprising the steps of a) mixing the polyol component (K1) and the polyisocyanate component (K2) of a two-component polyurethane composition as described above, b) applying the mixed polyurethane composition into the joint or gap of the substrate to be filled, c) curing the polyurethane composition in the joint or gap.

[0135] Particularly suitable substrates are metal, plastic, wood, glass, ceramics and fiber-reinforced plastics, especially metal and fiber-reinforced plastics.

[0136] In a further aspect, the invention therefore also comprises a filled article which has been filled according to the method described above.

[0137] The invention further relates to the use of the described polyurethane composition as an infusion resin, in particular for the production of fiber-reinforced composite parts, particularly preferably in infusion processes. For use as an infusion resin, in particular as an infusion resin for composite components, the two-component polyurethane composition (2K-PU composition) preferably has a viscosity in mixed form of 500 to 5000 mPas (measured with Brookfield RTV, speed 10 rpm, cone / plate, CP 50 / 1), measured at a temperature of 20°C. In particular, the viscosity should be 1000 to 2000 mPas, measured at 20°C. The viscosity should be determined immediately after mixing, for example, up to 1 minute after mixing; it increases steadily due to the onset of the crosslinking reaction.

[0138] The inventive 2-component PU composition has a sufficiently long open time for processing and application of the mixed composition. Once the open time is exceeded, the mixed composition cures rapidly. The open time should preferably be 10-30 minutes, especially 15-30 minutes. The "Gelation Time [min]" can be determined as a measure of the open time based on the time until tack-free, as described in the examples below.

[0139] The invention further relates to a process for producing fiber-reinforced composite parts and a two-component polyurethane composition described above, characterized in that the polyol component K1 and the polyisocyanate component K2 are mixed and then, in particular less than 5 minutes after mixing, preferably immediately after mixing, are introduced into a mold containing the fibers under vacuum and / or pressure.

[0140] The mixing of the polyol component K1 with the polyisocyanate component K2 can be carried out batchwise or continuously, preferably continuously.

[0141] If the two-component polyurethane composition is used as an adhesive or infusion resin, the cured composition preferably has the following properties (according to the measurement methods / measurement conditions used in the example section below, curing conditions 3h at 80°C):

[0142] Examples of substances used:

[0143] Production of polyurethane compositions

[0144] For each composition, the ingredients listed in Table 1 were processed into a homogeneous paste in the specified amounts (in parts by weight) of the polyol component K1 using a vacuum dissolver under moisture exclusion. The ingredients of the polyisocyanate component K2 listed in Table 1 were also processed and stored. Subsequently, the two components were processed into a homogeneous paste using a SpeedMixer® (DAC 150 FV, Hauschild) for 30 seconds (ratio of all NCO groups B1: all OH groups of the polyol component K1 = 1.07). This paste was then immediately tested as follows:

[0145] To determine the mechanical properties, the adhesive was shaped into a dumbbell according to ISO 527, Part 2, 1 B, and stored or cured for 7 days in a standard climate (23°C, 50% relative humidity) or, after storage in a standard climate for 12-24 hours, for 3 hours at 80°C. The elastic modulus in the range of 0.05 to 0.25% elongation ("E-modulus", "Em 0.05-0.25%"), the elastic modulus in the range of 0.5 to 5% elongation ("E-modulus", "Em 0.5-5%"), the tensile strength (TS) and the elongation at break (EB) of the test specimens produced in this way were then measured at room temperature according to ISO 527 on a Zwick Z020 tensile testing machine at a test speed of 10 mm / min.

[0146] The glass transition temperature, abbreviated in the tables as T g, was determined using DMTA measurements on strip-shaped samples (height 2-3 mm, width 2-3 mm, length 8.5 mm), which were stored or cured for 24 hours at 23°C and then for 3 hours at 80°C, using a Mettler DMA / SDTA 861 e device. The measurement conditions were: measurement in tensile mode, 10 Hz excitation frequency and heating rate 5 K / min. The samples were cooled to -70°C and heated to 200°C while determining the complex elastic modulus E* [MPa], with a maximum in the curve for the loss angle "tan δ" as T g -value was read. The results are shown in Table 1.

[0147]

[0148] Table 1, nb = not determined

[0149] Table 1 lists the components of polyol component K1 and polyisocyanate component K2 in parts by weight.

[0150] The values ​​(A1-1 + A1-2 + A2) / A3, (A1-1 + A1-2) / A3, (A1-1 + A1-2) / A2, and A3 / A2 in Table 1 refer to the ratio of the OH groups of A1-1 Neukapol 1119, A1-2 Neukapol 1565, A2 Polybd 45 HTLO, and A3 Propoxylated Dytek®A, respectively. The ratio described above refers to the molar ratio of the mentioned groups.

[0151] The term “Mixing ratio” indicates the proportion of component K2 in parts by weight that was added to 100 parts by weight of the corresponding component K1.

[0152] "Gelation Time [min]" was used as a measure of the open time to determine the time until the adhesive was tack-free. For this purpose, a few grams of the adhesive were applied to cardboard in a layer thickness of approximately 2 mm, and the time taken for the first time to leave no residue on the adhesive surface when lightly tapping the surface with an LDPE pipette was carried out under standard conditions.

[0153] E1 to E8 are examples according to the invention. R1 to R8 are comparative examples.

Claims

Patent claims 1 . Two-component polyurethane composition consisting of a polyol component K1 and a polyisocyanate component K2; wherein the polyol component K1 -at least one reaction product of epoxidized vegetable oils having a C-fatty acid content of more than 50% by weight, in particular more than 60% by weight, based on the total amount of fatty acids, with monofunctional C-s-alcohols A1-1; and / or -at least one reaction product of epoxidized fatty acid esters of monofunctional C-s-alcohols, in particular methanol, with aliphatic alcohols having an OH functionality in the range from 2 to 5, in particular glycerol, wherein the epoxidized fatty acid esters are based as fatty acid components on fatty acid mixtures which have a content of C-fatty acids, in particular unsaturated C-fatty acids, of at least 50% by weight, based on the total fatty acid mixture A1-2; and -preferably at least one polybutadiene polyol having an OH functionality in the range from 2.1 to 2.9, in particular 2.3 to 2.7, and having an average molecular weight in the range of 2000 to 4000 g / mol, in particular 2500 to 3000 g / mol, and an OH number of 40 - 100 mg KOH / g A2; and. -at least one alkoxylated branched alkylenediamine having 5 - 10 C atoms, in particular 6 - 9 C atoms, with an OH number of 450 - 800 mg KOH / g A3; and wherein the polyisocyanate component K2 comprises at least one aromatic polyisocyanate B1, and wherein the ratio of all NCO groups of the aromatic polyisocyanates B1 : all OH groups of the polyol component K1 = 0.9 : 1 - 1.2 : 1, in particular 1.0 : 1 - 1.1 :

1.

2. Two-component polyurethane composition according to claim 1, characterized in that the ratio of the OH groups of (A1-1 + A1-2 + A2) / (A3) is 1.1 - 10, preferably 1.2 - 3.5, particularly preferably 1.3 - 1.

75.

3. Two-component polyurethane composition according to one of the preceding claims, characterized in that the ratio of the OH groups of (A1-1 + A1-2) / (A3) is 1.1 - 10, preferably 1.2 - 3.5, particularly preferably 1.3 - 1.

75.

4. Two-component polyurethane composition according to one of the preceding claims, characterized in that the ratio of the OH groups of (A1-1 + A1-2) / (A2) is 5-30, preferably 10-25, particularly preferably 15-20.

5. Two-component polyurethane composition according to one of the preceding claims, characterized in that the ratio of the OH groups of (A3) / (A2) is from 5 to 25, preferably 7.5 to 20, particularly preferably 10 to 15.

6. Two-component polyurethane composition according to one of the preceding claims, characterized in that in the two-component polyurethane composition the sum of all OH groups of (A1-1 + A1-2 + A2 + A3) is >80%, preferably >90%, particularly preferably >95%, of the sum of all NCO-reactive groups, in particular OH groups, of the two-component polyurethane composition.

7. Two-component polyurethane composition according to one of the preceding claims, characterized in that it is an alkoxylated branched alkylenediamine having 5 - 10 C atoms with an OH number of 450 - 800 mg KOH / g A3 selected from the list consisting of N,N,N',N'-tetrakis(2-hydroxypropyl)-2-methyl-pentamethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)-2,2,4- Trimethylhexamethylenediamine and N,N,N',N'-tetrakis(2-hydroxypropyl)-2,4,4-trimethylhexamethylenediamine, in particular N,N,N',N'-tetrakis(2-hydroxypropyl)-2-methyl-pentamethylenediamine.

8. Two-component polyurethane composition according to one of the preceding claims, characterized in that the vegetable oils of A1-1 are vegetable oils selected from the list consisting of sunflower oil, rapeseed oil and castor oil, in particular sunflower oil and / or rapeseed oil.

9. Two-component polyurethane composition according to one of the preceding claims, characterized in that in A1-2 the content of oleic acid and linoleic acid in the fatty acid mixtures, based on the total fatty acid mixture, is at least 60% by weight, at least 70% by weight, in particular at least 80% by weight.

10. Two-component polyurethane composition according to one of the preceding claims, characterized in that the polyol component K1 comprises at least one reaction product A1-1 and at least one reaction product A1-2, the weight ratio (A1-1 / A1-2) being from 1:3 to 3:1, in particular 1:2 to 2:1, particularly preferably from 1:1 to 2:

1.

11. Two-component polyurethane composition according to one of the preceding claims, characterized in that the aromatic polyisocyanate B1 is monomeric MDI or oligomers, polymers and derivatives derived from MDI, in particular with an average NCO functionality of 2.0 to 4.0, preferably 2.0 to 3.0, in particular 2.1 to 2.

6.

12. Two-component polyurethane composition according to one of the preceding claims, characterized in that the aromatic polyisocyanate B1 comprises oligomers, polymers and Derivatives derived from MDI, in particular polymers derived from MDI, in particular with an average NCO functionality of 2.1 to 2.

6.

13. Two-component polyurethane composition according to one of the Claims 1 - 11, characterized in that the aromatic polyisocyanate B1 comprises monomers of MDI, in particular 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate and any mixtures of these isomers, in particular mixtures of 4,4'- and 2,4'-diphenylmethane diisocyanate, in particular with an NCO content of 31.0 - 34.0% by weight.

14. Method for bonding a first substrate to a second Substrate comprising the steps -mixing the polyol component (K1) and the polyisocyanate component (K2) of a two-component polyurethane composition according to one of claims 1 to 13, -Applying the mixed polyurethane composition to at least one of the substrate surfaces to be bonded, -Joining the substrates to be bonded within the open time, -Curing of the polyurethane composition.

15. A method for filling joints and gaps in a substrate comprising the steps of a) mixing the polyol component (K1) and the polyisocyanate component (K2) of a two-component polyurethane composition according to one of claims 1 to 13, b) applying the mixed polyurethane composition into the joint or gap in the substrate to be filled, c) curing the polyurethane composition in the joint or gap.

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