Two-component polyurethane composition with high hydrophobicity and adjustable pot life

Abstract

This invention relates to polyurethane compositions comprising a first component A and a second component B, wherein the first component A contains a polyol mixture P ranging from 30% to 99% by weight based on component A, said polyol mixture P comprising 100 parts by weight of at least one hydrophobic polyol P1, 10 to 75 parts by weight of at least one hydrophilic polyol P2, and 0 to 25 parts by weight of at least one diol P3 having two hydroxyl groups linked by a C2-C9 carbon chain, and at least one compound T having at least one thiol group; and the second component B comprises at least one polyisocyanate I, wherein one of the two components further comprises at least one metal catalyst K (capable of forming a thiocomplex) for the reaction of the hydroxyl groups with the isocyanate groups, and the molar ratio of all thiol groups in at least one compound T to all metal atoms in at least one metal catalyst K is between 1:1 and 250:1. Such compositions allow the open time of the hydrophobic polyurethane composition to be arbitrarily set within specific limits, and allow for long open times followed by very rapid curing of the composition. The compositions of this invention are particularly suitable as hydrophobic structural adhesives for bonding two substrates or as matrices for composite materials.

Description

Technical Field

[0001] This invention relates to the field of two-component polyurethane compositions and their uses, particularly as a matrix or adhesive in composite materials. Existing technology

[0002] Two-component polyurethane compositions based on polyols and polyisocyanates have been used for some time. Two-component polyurethane compositions have an advantage over one-component compositions in that they cure rapidly after mixing and therefore can absorb and transfer high forces in a very short time. For use as structural adhesives or as a matrix (adhesive) in composite materials, such compositions must meet high requirements regarding strength and adhesion, as these adhesives are the structural elements bearing the load. In particular, such compositions need to possess good mechanical properties upon curing, such as a high modulus of elasticity, while having low elongation values ​​and high tensile and tensile shear strengths, but must not be brittle. Furthermore, for example, in industrial manufacturing, it is desirable for such compositions to cure as quickly as possible, reducing production time.

[0003] To achieve the desired mechanical properties and, first and foremost, particularly rapid curing, it is advantageous when such compositions contain a high proportion of isocyanate, which exists in one of the two components as a free or polymerically bonded polyisocyanate and cures to form a polymer network after mixing with the other component containing a polyol. However, high isocyanate content does indeed cause problems. Especially with the use of crosslinking catalysts necessary for optimal selective crosslinking and curing, such two-component systems become almost uncontrollably fast and have too short a pot life, for example, when used as structural adhesives. For use as adhesives in composites, a sufficiently long pot life is also required to allow for uniform fiber embedding into the matrix.

[0004] When using two-component polyurethane compositions, it is generally desirable to combine a sufficiently long pot life with subsequent very rapid curing and extremely fast strength development. However, this is virtually impossible to achieve with today's two-component compositions. Either the pot life is very short when the composition cures and develops strength rapidly, or curing and strength development are slow when dealing with compositions that have a long pot life.

[0005] Therefore, two-component polyurethane compositions with long pot lifespans, which can be adjusted even within certain limits, have been developed, allowing for the processing of larger parts or the production of components, while also exhibiting very rapid curing and strength and elasticity after application, in a structural bonding sense within a very short time, such as hours to days. One such two-component polyurethane composition is disclosed in WO 2019 / 002538 A1. This disclosure teaches a specialized catalyst system comprising a metal catalyst and a compound containing a thiol group, which allows for an adjustable long pot life and then very rapid curing of the composition.

[0006] Similar two-component polyurethane compositions containing such catalyst systems are disclosed in US 5587 448A. The taught two-component polyurethane compositions are primarily based on various polypropylene glycol-based polyether polyols and are particularly suitable as coatings.

[0007] In the case of two-component polyurethane compositions, a wide range of mechanical properties, ranging from soft elasticity to highly structured properties, can be achieved through the appropriate assembly of individual components.

[0008] Furthermore, two-component polyurethane compositions, along with the aforementioned rapid strength-building properties, offer a further advantage in that they can be composed solely of hydrophobic raw materials, particularly by using polymers containing isocyanate groups and based on hydrophobic polyols. This is far from possible for one-component polyurethanes that cure via atmospheric moisture, as the diffusion of water in hydrophobic compositions is severely limited. As a result of the hydrophobicity, adhesives obtained from such two-component compositions after curing typically exhibit only low water absorption and improved aging resistance. Mechanical properties are also often excellent. Additionally, adhesion formation on low-energy surfaces such as polyolefins or polycarbonates is significantly improved compared to polyurethanes based on polar units.

[0009] Examples of polyurethane adhesives based on hydrophobic polybutadiene are described in US 4,812,524 A. The adhesive disclosed in US 4,812,524 is based on a combination of amine-terminated and hydroxyl-terminated polybutadiene, which reacts with polyisocyanate to obtain polyurethane. The adhesive is said to exhibit excellent adhesive properties and strong bonding to steel substrates.

[0010] Another two-component hydrophobic polyurethane adhesive is taught in WO 2017 / 017089 A1. The compositions disclosed in this publication are based on hydrophobic polybutadiene polyols and hydrophobic diols selected from polybutadiene glycol, polyester glycol, polycarbonate glycol, and also from polyether glycols having at least four carbon atoms in their repeating units. Thiosilanes are also taught, but only as adhesion promoters.

[0011] CN 110 669 469A also teaches hydrophobic two-component polyurethane adhesives, such as those based on polybutadiene polyols and polyester polyols. Thiosilanes are also taught here, but only as silane crosslinking agents.

[0012] WO 2019 / 195045 A1 also teaches hydrophobic two-component polyurethane compositions as adhesives, specifically for polypropylene substrates. These compositions are based on hydrophobic polyols selected from poly(epoxybutane) polyols, polybutadiene polyols, and acrylate polyols. A dithiol dioctyltin catalyst is used in the examples.

[0013] However, such hydrophobic two-component polyurethane compositions containing isocyanate groups and based on hydrophobic polyols exhibit very poor compatibility with the specialized catalyst systems described above, which offer adjustable, long pot lifespans and rapid curing. It has been found that such hydrophobic two-component polyurethane compositions cannot be readily catalyzed using systems taught, for example, in WO 2019 / 002538A1. The effect of rapid curing after the pot life is far less significant than in the case of the hydrophilic polyurethane compositions disclosed in WO 2019 / 002538A1.

[0014] Therefore, it is desirable to obtain a hydrophobic two-component polyurethane composition that has all the advantages of the hydrophobic composition described above, but still contains a catalyst system that exhibits a long, adjustable pot life and subsequent extremely rapid curing. Invention Overview

[0016] The object of the present invention is therefore to provide a hydrophobic two-component polyurethane composition that cures very quickly to form a mechanically excellent material suitable as a structural adhesive or as a matrix for composite materials, but at the same time has a suitably long pot life that can be adjusted within certain limits, thereby allowing for handling without problems.

[0017] This objective is surprisingly achieved using the polyurethane composition according to the invention. It comprises a mixture of polyols containing at least one hydrophobic polyol and at least one hydrophilic polyol (optionally a short-chain diol), a compound having at least one thiol group in the first component, and a polyisocyanate in the second component. For the cured composition, the composition also contains a metal catalyst capable of forming a thiocomplex, and the ratio of thiol groups to metal atoms in the composition is fixed. Upon curing, the composition exhibits very high strength and good elasticity. After mixing the components and after a suitably long pot life adjustable within certain limits, it cures very rapidly and achieves very good mechanical properties in just a short time, such as a few hours to a day.

[0018] Other aspects of the invention are the subject of the other independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims.

[0019] Methods of implementing the present invention

[0020] This invention relates to a polyurethane composition comprising a first component A and a second component B, wherein...

[0021] - Component A contains

[0022] - A polyol mixture P comprising between 30% and 99% by weight of component A, wherein the polyol mixture P contains

[0023] -100 parts by weight of at least one hydrophobic polyol P1,

[0024] -10 to 75 parts by weight of at least one hydrophilic polyol P2

[0025] -0 to 25 parts by weight of at least one diol P3, said diol P3 having two hydroxyl groups linked by a C2-C9 carbon chain, and

[0026] - At least one compound T having at least one thiol group; and

[0027] - Component B contains

[0028] - At least one polyisocyanate I;

[0029] One of the two components also contains at least one metal catalyst K capable of forming a thiocomplex for the reaction of the hydroxyl group with the isocyanate group, and

[0030] The molar ratio of all thiol groups in at least one compound T to all metal atoms in at least one metal catalyst K is between 1:1 and 250:1.

[0031] In this document, the prefix "poly(poly)" in substance names such as "poly(poly)ol", "poly(poly)isocyanate", "poly(poly)ether" or "poly(poly)amine" indicates that each molecule contains more than one functional group that appears under its name.

[0032] In this document, the term "polymer" primarily refers to a collection of macromolecules that are chemically homogeneous but differ in degree of polymerization, molar mass, and chain length, produced by a "polymerization" reaction (polymerization, addition polymerization, condensation polymerization). The term also includes derivatives of such a collection of macromolecules from a "polymerization" reaction, i.e., compounds obtained by reactions of functional groups on defined macromolecules, such as addition or substitution, and which may be chemically homogeneous or chemically heterogeneous. The term also includes so-called prepolymers, i.e., adducts initiated from reactive oligomers whose functional groups participate in the formation of macromolecules.

[0033] The term "polyurethane polymer" includes all polymers produced according to the so-called diisocyanate addition polymerization process. This also includes polymers that contain little or no urethane groups. Examples of polyurethane polymers are polyether polyurethanes, polyester polyurethanes, polyether polyurea, polyurea, polyester polyurea, polyisocyanurate, and polycarbodiimide.

[0034] In this document, "molecular weight" should be understood as referring to the molar mass (in grams per mole) of a molecule or molecular residue. "Average molecular weight" refers to the number-average Maverage of a polydisperse mixture of oligomer or polymer molecules or molecular residues. nIt is usually determined by gel permeation chromatography (GPC) using polystyrene as a standard.

[0035] Weight percentage values, abbreviated as % by weight, refer to the proportion of an ingredient in the composition based on the mass of the whole composition, unless otherwise stated. The terms “mass” and “weight” are used synonymously in this document.

[0036] A "primary hydroxyl group" refers to an OH group attached to a carbon atom with two hydrogen atoms.

[0037] In this document, "suitable period" refers to the time after mixing the two components during which the polyurethane composition can be processed before the viscosity produced by the crosslinking reaction becomes too high for further processing.

[0038] The term “strength” in this document refers to the strength of the cured composition, specifically meaning tensile strength and modulus of elasticity, particularly in the range of 0.05% to 0.25% elongation or 0.5% to 5.0% elongation.

[0039] In this document, "room temperature" refers to a temperature of 23°C.

[0040] A substance or composition is described as “storage stable” or “storable” if it can be stored at room temperature in a suitable container for a relatively long period of time, typically at least 3 months to 6 months or longer, without causing any change in its application or use properties, particularly viscosity and crosslinking rate, to the extent relevant to its use.

[0041] All industry standards and specifications mentioned in this document relate to the valid version as of the date of initial submission.

[0042] "Average OH functionality" is the average number of OH groups per polymer molecule across all polymer molecules. For example, if 50% of all polymer molecules contain two hydroxyl groups and the other 50% contain three, the result is an average OH functionality of 2.5. Average OH functionality can be specifically determined by the hydroxyl group value and the molecular weight M as measured via GPC. n The calculation is determined.

[0043] The polyurethane composition of the present invention consists of a first component A and a second component B, which are mixed only when the polyurethane composition is applied and stored in separate packages prior to this.

[0044] First component A contains a polyol mixture P ranging from 30% to 99% by weight based on component A, said polyol mixture P comprising...

[0045] -100 parts by weight of at least one hydrophobic polyol P1,

[0046] -10 to 75 parts by weight of at least one hydrophilic polyol P2

[0047] -0 to 25 parts by weight of at least one diol P3, said diol P3 having two hydroxyl groups linked by a C2-C9 carbon chain, and at least one compound T having at least one thiol group.

[0048] The first component A therefore initially contains at least one hydrophobic polyol P1. This is present in the polyol mixture P, which is present in the composition of the invention at an amount between 30% by weight and 99% by weight based on component A.

[0049] The polyol mixture P preferably contains between 40% and 80% by weight, particularly between 45% and 75% by weight, and most preferably between 50% and 70% by weight, based on component A.

[0050] The polyol mixture P contains 100 parts by weight of at least one hydrophobic polyol P1.

[0051] The hydrophobic polyol P1 preferably has an OH functionality in the range of 1.5-4 and an average molecular weight in the range of 250-15000 g / mol.

[0052] The term "hydrophobic" in relation to polyol P1 should be understood to mean that the parent polymer of the polyol has not been significantly modified by hydrophilic functional groups, for example, in the form of polar functional groups on the main chain or additional side chains formed by hydrophilic polyethers such as polyethylene glycol and polypropylene glycol, because such modification would significantly impair the hydrophobic properties. In the context of this invention, it is therefore preferred that the parent polymer of polyol P1 consists of the aforementioned materials, i.e., polybutadiene, polyester, polycarbonate, and polyethers having repeating units having at least four carbon atoms. Polyethers having at least four carbon atoms in the repeating units, such as poly(epoxybutane) polyols or poly(1,4-butanediol), or poly(butanediol), are considered hydrophobic polyols.

[0053] Suitable as hydrophobic polyol P1 are, in particular, polybutadiene polyols, hydrophobic polyester polyols, hydrophobic polycarbonate polyols, polyester polyols based on dimer fatty acids, and hydrophobic polyether polyols having repeating units with at least 4 carbon atoms between two ether oxygen atoms, such as poly(epoxybutane) polyols.

[0054] In a preferred embodiment, the hydrophobic polyol P1 is a polybutadiene polyol, a polyester polyol based on dimer fatty acids, polytetrahydrofuran diol, or a mixture of said polyols.

[0055] Polybutadiene polyols with an average molecular weight in the range of 2000-10000 g / mol and an average OH functionality in the range of 2.1-4 are preferred as hydrophobic polyol P1.

[0056] The average molecular weight of polybutadiene polyol is preferably in the range of 2000-4000 g / mol, especially in the range of 2500-3000 g / mol.

[0057] The average OH functionality of the polybutadiene polyol is preferably in the range of 2.1-2.9, especially in the range of 2.3-2.7.

[0058] Such polybutadiene polyols can be obtained in a simple manner and have relatively low viscosity, which allows for good processability of the composition.

[0059] Suitable polybutadiene polyols can be obtained, in particular, by polymerization of 1,3-butadiene and allyl alcohol in a suitable ratio or by oxidation of suitable polybutadiene or its hydrogenated products.

[0060] Suitable polybutadiene polyols contain structural elements of formula (I) and optional structural elements of formula (II) or (III).

[0061]

[0062] Preferred polybutadiene polyols contain

[0063] 40% to 80%, especially 55% to 65%, of the structural elements of formula (I),

[0064] 0% to 30%, especially 15% to 25%, of the structural elements of formula (II),

[0065] 0% to 30%, especially 15% to 25% of the structural elements of formula (III).

[0066] Particularly suitable polybutadiene polyols are R-45HTLO or R-45M (all from Cray Valley).

[0067] Additionally, polyhydric polyols, also known as oligohydric alcohols, are also suitable as polymer P1. Examples include polyhydroxy-functionalized ethylene-propylene, ethylene-butene, or ethylene-propylene-diene copolymers, such as those produced by Kraton Polymers in the United States; polyhydroxy-functionalized copolymers of dienes such as 1,3-butadiene or mixtures of dienes and vinyl monomers such as styrene, acrylonitrile, or isobutene; or polyhydroxy-functionalized polybutadiene polyols, such as those produced by copolymerizing 1,3-butadiene and allyl alcohol, which can also be hydrogenated.

[0068] Another suitable polymer P1 is a polyhydroxy-functionalized acrylonitrile / butadiene copolymer, such as those produced, for example, from acrylonitrile / butadiene copolymers end-capped with epoxides or amino alcohols and carboxyl groups, which can... Name (original) CTBN was purchased from Emerald Performance Materials, LLC in the United States.

[0069] Also suitable is a hydrophobic polyol P1 having an average molecular weight in the range of 500-5000 g / mol, selected from the following: polybutadiene glycol, polyester glycol, polycarbonate glycol and polyether glycol having repeating units with at least 4 carbon atoms, wherein the polyether glycol having repeating units with at least 4 carbon atoms is preferably polytetrahydrofuran glycol.

[0070] In another preferred embodiment, the hydrophobic polyol P1 is preferably an aliphatic or cycloaliphatic polyol having an average OH functionality between 2 and 4 and free of aromatic substituents.

[0071] These are preferably aliphatic or cycloaliphatic polyols, preferably polytetrahydrofuran diol or polycarbonate diols based on 3-methyl-1,5-pentanediol and 1,6-hexanediol, or polyester carbonate diols based on 1,6-hexanediol and ε-caprolactone, or polyester diols based on 3-methyl-1,5-pentanediol and adipic acid or sebacic acid.

[0072] Particularly suitable polyester polyols are the condensation products of 3-methyl-1,5-pentanediol and adipic acid or sebacic acid. This type of polyester polyol can be, for example, used as... The product name P-2010 was obtained from Kuraray.

[0073] Particularly suitable aliphatic polycarbonate polyols based on 3-methyl-1,5-pentanediol and 1,6-hexanediol can be, for example, The product name C-2050 is derived from Kuraray.

[0074] Particularly suitable aliphatic polyester carbonate polyols based on 1,6-hexanediol and ε-caprolactone can The product name C 1200 is derived from Bayer Material Science.

[0075] As the hydrophobic polyol P1, polyester polyols based on dimer fatty acids obtained from oil-based (renewable) raw materials are particularly preferred.

[0076] This type of polyester polyol based on dimer fatty acids is preferably a liquid at room temperature. It particularly has an OH value in the range of 28-120 mg KOH / g.

[0077] Such polyester polyols based on dimer fatty acids have average molecular weights in the range of 950-4000 g / mol. They often have a substantially linear structure and an average OH functionality of about 2, especially between 2 and 2.5.

[0078] Polyester polyols based on dimer fatty acids are preferably amorphous.

[0079] Suitable polyester diols based on dimer fatty acids as polymer P1 are obtained, in particular, from the esterification of at least one dimer fatty acid and / or at least one dimer fatty alcohol with a diol such as ethylene glycol or butanediol, and / or a dicarboxylic acid such as adipic acid in such stoichiometric ratios that the product is amorphous and liquid at room temperature and has an OH value in the range of 28-120 mg KOH / g.

[0080] Polyester polyols based on dimer fatty acids preferably have a carbon atom content from renewable sources according to ASTM D6866, ranging from 50-100% of the total carbon content, preferably 60-95%, and especially 70-90%. Such polyester polyols are amorphous and hydrophobic, and exhibit particularly good compatibility in polyurethane adhesives.

[0081] The dimer-fatty acid-based polyester polyol used as polymer P1 preferably has an OH value in the range of 34-120 mg KOH / g, especially 52-60 mg KOH / g. Such dimer-fatty acid-based polyester polyols have an average molecular weight in the range of 950-3300 g / mol, especially in the range of 1900-2200 g / mol. Such polymers allow polyurethane compositions to possess a particularly attractive combination of good extrudability, good adhesion, and high strength.

[0082] Commercially available amorphous polyester polyols based on dimer fatty acids are particularly suitable, especially those with... The following brands are available for the product name: 1837, 1838, 3187, 3196, 3197, 3199, or 3238 (from Croda). These are preferred. 1838. Also suitable is one from VASF. Brand name, especially RC 1005 and 805.

[0083] In all embodiments, the hydrophobic polyol P1 preferably has an average molecular weight in the range of 400-3500 g / mol, especially 500-3250 g / mol, more preferably 750-3000 g / mol, and most preferably in the range of 1000-3000 g / mol.

[0084] In all embodiments, the hydrophobic polyol P1 preferably has an average OH functionality in the range of 2-4, especially 2-3.5, more preferably 2-3, and most preferably 2-2.5.

[0085] The hydrophobic polyol P1 has a hydroxyl value in all embodiments ranging from 45 to 600 mg KOH / g, especially 50 to 500 mg KOH / g, more preferably 50 to 250 mg KOH / g, and most preferably in the range of 50 to 200 mg KOH / g.

[0086] The first component A also contains at least one hydrophilic polyol P2. This is present in the polyol mixture P.

[0087] The polyol mixture P contains 10 to 75 parts by weight of at least one hydrophilic polyol P2.

[0088] When the amount of hydrophilic polyol P2 / 100 parts by weight of hydrophobic polymer P1 is less than 10 parts by weight, the long pot life and subsequent rapid curing produced by the present invention can no longer be satisfactorily achieved.

[0089] Conversely, when the amount of hydrophobic polymer P1 in 100 parts by weight of hydrophilic polyol P2 is greater than 75 parts by weight, the hydrophobicity of the overall composition can no longer be satisfactorily adjusted.

[0090] Generally, a higher proportion of hydrophilic polyol P2 tends to enhance the effects according to the invention, i.e., faster curing after the pot life. On the other hand, a lower proportion of hydrophilic polyol P2 tends to improve the positive properties of hydrophobicity (e.g., lower water absorption, improved anti-aging properties, better adhesion to low-energy substrates) and mechanical properties. Depending on the desired application and the associated desired properties, the ratio of polyols P1 and P2 can therefore be adjusted within given limits as needed. Furthermore, the properties mentioned above may also be affected by other components in the composition, such as fillers and the diol P3 described below, meaning that other options exist for influencing the properties of the composition through formulation measures.

[0091] Suitable hydrophilic polyols P2 are, in principle, common hydrophilic polyols used in the production of polyurethane polymers, which can be used in conventional one-component polyurethane compositions cured by atmospheric moisture. Particularly suitable are hydrophilic polyether polyols, hydrophilic polyester polyols, hydrophilic poly(meth)acrylate polyols, and hydrophilic polycarbonate polyols, as well as mixtures of said polyols.

[0092] Suitable as polymers P2 are those polyether polyols (also known as polyoxyalkylene polyols or oligoether alcohols), particularly those from the polymerization of ethylene oxide, 1,2-epoxypropane, oxetane, or mixtures thereof, optionally polymerized by means of an initiating molecule having two or more active hydrogen atoms, such as water, ammonia, or compounds having multiple OH or NH groups, such as 1,2-ethylene glycol, 1,2-propanediol, and 1,3-propanediol. Alcohols, neopentyl glycol, diethylene glycol, triethylene glycol, isomeric dipropylene glycol and tripropylene glycol, isomeric butanediol, pentylene glycol, hexanediol, heptaethylene glycol, octyl glycol, nonanediol, decanediol, undecanediol, cyclohexane-1,3-diethanol and cyclohexane-1,4-diethanol, bisphenol A, hydrogenated bisphenol A, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, aniline, and mixtures of the listed compounds. Polyoxyalkylene polyols with low unsaturation (measured according to ASTM D-2849-69 and expressed as milliequivalents of unsaturation per gram of polyol (mEq / g)) can be used, for example, with so-called bimetallic cyanide complex catalysts (DMC catalysts), or polyoxyalkylene polyols with relatively high unsaturation, for example, with anionic catalysts such as NaOH, KOH, CsOH, or alkali metal alkoxides.

[0093] Polyoxyethylene polyols and polyoxypropylene polyols, especially polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene triol and polyoxypropylene triol, are particularly suitable as polyols P2.

[0094] Polyoxyalkylene glycols or polyoxyalkylene triols with an unsaturation degree of less than 0.02 mEq / g and a molecular weight in the range of 1000-15000 g / mol are particularly suitable as polyoxyethylene glycols, polyoxyethylene triols, polyoxypropylene glycols, and polyoxypropylene triols with a molecular weight of 400-15000 g / mol.

[0095] Also particularly suitable as polyol P2 are so-called ethylene oxide-terminated ("EO-terminated") polyoxypropylene polyols. The latter are special polyoxypropylene polyoxyethylene polyols, which are obtained, for example, by further alkoxylation of pure polyoxypropylene polyols, especially polyoxypropylene diols and triols, with ethylene oxide at the end of the polypropoxylation reaction and thus possessing primary hydroxyl groups. In this case, polyoxypropylene polyoxyethylene diols and polyoxypropylene polyoxyethylene triols are preferred.

[0096] Suitable polyether-based polymers of this type, such as P2, can be used as examples. and Product name, especially 4200 5034 1381BT and 28HS98 was obtained from Coves tro. Product name, especially EP1900 and CP 4755, obtained from Dow, and with Product name, especially 3130 HP obtained from Arkema.

[0097] Also suitable are styrene-acrylonitrile grafted polyether polyols, for example, under the trade name... Those were purchased from Elas togran GmbH in Germany.

[0098] Suitable hydrophilic polyester polyols, especially those carrying at least two hydroxyl groups, and polyesters produced by known methods, particularly the condensation polymerization of hydroxycarboxylic acids or the condensation polymerization of aliphatic and / or aromatic polycarboxylic acids with diols or polyols.

[0099] Particularly suitable are polyester polyols formed from diols to triols such as 1,2-ethylene glycol, diethylene glycol, 1,2-propanediol, dipropylene glycol, or mixtures of the alcohols mentioned above, and organic dicarboxylic acids or their anhydrides or esters such as succinic acid, glutaric acid, adipic acid, trimethyl adipic acid, maleic acid, fumaric acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, dimethyl terephthalate, hexahydrophthalic acid, trimellitic acid, and trimellitic anhydride or mixtures of the above acids, as well as polyester polyols formed from lactones such as ε-caprolactone.

[0100] Particularly preferred are hydrophilic polyester diols, especially those produced from adipic acid, phthalic acid, isophthalic acid and terephthalic acid as dicarboxylic acids or from lactones such as ε-caprolactone and from ethylene glycol, diethylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol and cyclohexane-1,4-diethanol as diols.

[0101] Suitable examples of hydrophilic polyester polyols are... Those product names obtained from Kuraray, especially F-510, and can Those product names obtained from King Industries, especially 188.

[0102] Suitable hydrophilic polycarbonate polyols particularly include those that can be obtained by reacting alcohols, such as those mentioned above for forming polyester polyols, with dialkyl carbonates such as dimethyl carbonate, diaryl carbonates such as diphenyl carbonate, or phosgene. Also suitable are polycarbonates that can be obtained by copolymerizing CO2 with epoxides such as ethylene oxide and propylene oxide. Polycarbonate diols, especially amorphous polycarbonate diols, are particularly suitable.

[0103] Another suitable polyol is the hydrophilic poly(meth)acrylate polyol.

[0104] Particularly suitable polyols P2 are hydrophilic polyester polyols and particularly preferred hydrophilic polyether polyols, especially polyoxyethylene polyols, polyoxypropylene polyols, and polyoxypropylene polyoxyethylene polyols, preferably polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene triol, polyoxypropylene triol, polyoxypropylene polyoxyethylene glycol and polyoxypropylene polyoxyethylene triol.

[0105] Most preferably, the hydrophilic polyol P2 is a polyether polyol, especially a polyether polyol having an average OH functionality of at least 2.5, and preferably a polyether polyol having propylene glycol repeating units in the polymer backbone.

[0106] In all embodiments, the hydrophilic polyol P2 preferably has an average molecular weight in the range of 400-6000 g / mol, especially 450-5500 g / mol, more preferably 500-5000 g / mol, and most preferably in the range of 550-5000 g / mol.

[0107] In all embodiments, the hydrophilic polyol P2 preferably has an average OH functionality in the range of 2-4, especially 2-3.5, and more preferably 2-3.

[0108] The hydrophilic polyol P2 has a hydroxyl value in all embodiments ranging from 20 to 500 mg KOH / g, especially from 25 to 400 mg KOH / g, and more preferably from 25 to 250 mg KOH / g.

[0109] The first component A also preferably contains at least one diol P3, said diol P3 having two hydroxyl groups linked by a C2-C9 carbon chain. This is present in the polyol mixture P.

[0110] The polyol mixture P contains 0 to 25 parts by weight of at least one diol P3, said diol P3 having two hydroxyl groups linked by a C2-C9 carbon chain.

[0111] For the effects according to the invention, the diol P3 need not be present in the polyol mixture P. However, it is advantageous, particularly for the mechanical properties of the polyurethane compositions of the invention, to have such a diol P3 present.

[0112] The preferred embodiment of the composition of the invention therefore preferably contains between 5 parts by weight and 25 parts by weight, especially between 10 parts by weight and 20 parts by weight, of a hydrophobic polymer P1 in the form of diol P3 / 100 parts by weight.

[0113] Suitable diols for P3 include straight-chain or branched alkylene glycols having two primary or secondary hydroxyl groups, alkylene glycols having one primary hydroxyl group and one secondary hydroxyl group, and cyclic aliphatic glycols.

[0114] Diol P3 is preferably a straight-chain aliphatic diol having two primary hydroxyl groups linked by a C4-C9 carbon chain. Such a diol is advantageous for producing polyurethanes with particularly high elastic modulus in a low elongation range, for example, between 0 and 5%, which is particularly beneficial for structural adhesives.

[0115] Specifically, diol P3 is selected from the following: ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,3-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 2,4-pentanediol, 2-methyl-1,4-butanediol, and 2,2-dimethyl-1,3-propanediol. (neopentylene glycol), 1,2-hexanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,2-octanediol, 3,6-octanediol, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,7-dimethyl-3,6-octanediol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, and 1,4-cyclohexanediol.

[0116] Diol P3 is particularly preferably selected from the following: 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol and 1,9-nonanediol.

[0117] The preferred diol P3 is selected from the following: 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,9-nonanediol. These diols are readily available commercially and, when cured, provide polyurethanes with particularly high elastic modulus at low elongation.

[0118] In addition to the polyols P1 and P2 and diol P3 described above, small amounts of other low molecular weight diols or polyols such as diethylene glycol, triethylene glycol, isomeric dipropylene glycol and tripropylene glycol, isomeric decanediol and undecanediol, hydrogenated bisphenol A, dimer fatty alcohols, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, pentaerythritol, sugar alcohols such as xylitol, sorbitol, or mannitol, sugars such as sucrose, other higher polyols, low molecular weight alkoxylated products of the aforementioned diols and polyols, and mixtures of the aforementioned alcohols may also be present. Furthermore, polyols containing other heteroatoms such as methyldiethanolamine or thiodiethylene glycol may also be present.

[0119] The first component A further comprises at least one compound T having at least one thiol group. Preferably, all compounds have at least one thiol or mercapto group, which can be formulated into the compositions of the present invention. The thiol group is to be understood herein as a -SH group attached to an organic group such as an aliphatic, cycloaliphatic or aromatic carbon group.

[0120] Compounds having 1-6, especially 1-4, and most preferably 1 or 2 thiol groups are preferred. Compounds with thiol groups have the advantage of not forming complexes with the metal catalyst K, which tend to have poor solubility, and the ability to precisely adjust the pot life. Compounds with two thiol groups have the advantage of improved mechanical properties of the composition upon curing.

[0121] Suitable examples of compounds T having a thiol group are 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyl-1,2-diol, 2-mercaptotolueneimidazole, or 2-mercaptobenzothiazole.

[0122] Suitable examples of compounds T having more than one thiol group are ethylene glycol di(3-mercaptopropionate), ethylene glycol dimercaptoacetate, pentaerythritol hexa(3-mercaptopropionate), 2,3-dimercapto-1,3,4-thiadiazole, or pentaerythritol tetra(3-mercaptopropionate).

[0123] Compound T is preferably selected from the following: ethylene glycol di(3-mercaptopropionate), ethylene glycol dimercaptoacetate, dipentaerythritol hexa(3-mercaptopropionate), and 3-mercaptopropyltrimethoxysilane.

[0124] The molar ratio of all thiol groups in at least one compound T to all metal atoms in at least one metal catalyst K must be between 1:1 and 250:1. Preferably between 2:1 and 150:1, and particularly between 5:1 and 100:1. This quantitative ratio allows for adjustment of the pot life by, for example, the content of the catalyst, the reactivity of the isocyanate present, and its amount, especially within the inherent limits of a particular composition. The lower limit of the pot life is the pot life obtained in a given composition when a specific amount of catalyst is used without the addition of compound T. In many cases, the invention is suitable for use as a structural adhesive or composite matrix, and due to the large number of isocyanate groups in the presence of a catalyst but without compound T, the actual pot life is not reached at all, and the composition begins to cure almost immediately upon mixing the two components.

[0125] Without a catalyst, the upper limit of the adjustable pot life is therefore the pot life achievable through the uncatalyzed isocyanate-hydroxyl reaction. Even without a catalyst, this reaction will begin sometime after the two components are mixed. However, the reaction proceeds more slowly without a catalyst, and the mechanical properties of the cured material deteriorate.

[0126] The key advantage achieved by the two-component polyurethane composition of the present invention is a system that cures and develops strength very quickly while having a sufficiently long pot life that allows it to be processed in a user-friendly manner. This means, for example, that structural bonding can also be achieved on relatively large substrates that can withstand mechanical stress only for a very short time after the adhesive is applied. This, for example, results in a significant reduction in production time in industrial manufacturing. Another advantage of the polyurethane composition of the present invention is the possibility of adjusting the pot life, as described above. This is particularly advantageous in automotive applications and can, for example, allow for further optimization of production time in industrial manufacturing, as the pot life can be adjusted according to the desired application.

[0127] The amount of compound T in the first component A is preferably in the range of 0.1 wt% to 5 wt%, more preferably 0.2 wt% to 2.5 wt%, and especially 0.25 wt% to 1.0 wt%, based on component A.

[0128] Based on the overall polyurethane composition, the amount of compound T is preferably in the range of 0.04 wt% to 2.0 wt%, more preferably 0.08 wt% to 1.0 wt%, and especially 0.1 wt% to 0.4 wt%, based on the overall polyurethane composition.

[0129] The second component B primarily contains at least one polyisocyanate I.

[0130] Polyisocyanate I is preferably present in a relatively high amount, which is very beneficial for forming sufficiently good mechanical properties for use as a structural adhesive or composite matrix.

[0131] The second component B preferably contains sufficient polyisocyanate I, such that at least 5% by weight, especially at least 6% by weight, and preferably at least 7.5% by weight isocyanate groups are present in the entire polyurethane composition.

[0132] The polyisocyanate I used to produce the polyurethane polymer in the compositions of the present invention can be any commercially available polyisocyanate suitable for polyurethane production, especially diisocyanate.

[0133] Suitable polyisocyanates, particularly monomeric diisocyanates or triisocyanates, as well as oligomers, polymers, and derivatives of monomeric diisocyanates or triisocyanates, and any desired mixtures thereof.

[0134] Suitable aromatic monomeric diisocyanates or triisocyanates, especially toluene-2,4- and toluene-2,6-diisocyanates and any desired mixtures of these isomers (TDI); diphenylmethane 4,4'-, 2,4'- and 2,2'-diisocyanates and any desired mixtures of these isomers (MDI); mixtures of MDI and MDI homologues (polymeric MDI or PMDI); 1,3- and 1,4-phenylene diisocyanates; 2,3,5,6-tetramethyl-1,4-diisocyanophenyl; naphthalene 1,5-diisocyanate (NDI); 3,3'-dimethyl-4,4'-diisocyanodiphenyl (TODI); o-anisidine diisocyanate (DADI); 1,3,5-tris(isocyanomethyl)benzene; tris(4-isocyanophenyl)methane; and tris(4-isocyanophenyl)thiophosphate.

[0135] Suitable aliphatic monomer diisocyanates or triisocyanates, especially tetramethylene-1,4-diisocyanate, 2-methyl-pentamethylene-1,5-diisocyanate, hexamethylene-1,6-diisocyanate (HDI), 2,2,4- and 2,4,4-trimethylhexamethylene-1,6-diisocyanate (TMDI), decamethylene-1,10-diisocyanate, dodecamethylene-1,12-diisocyanate, lysine diisocyanate and lysine esters. Diisocyanates, cyclohexane-1,3- and -1,4-diisocyanates, 1-methyl-2,4-diisocyanocyclohexane and -2,6-diisocyanocyclohexane and any desired mixtures of these isomers (HTDI or H6TDI), 1-isocyano-3,3,5-trimethyl-5-isocyanomethylcyclohexane (= isophorone diisocyanate or IPDI), perhydrodiphenylmethane 2,4'- and 4,4'-diisocyanates (HMDI or H6TDI) 12MDI), 1,4-diisocyanate-2,2,6-trimethylcyclohexane (TMCDI), 1,3- and 1,4-bis(isocyanate-methyl)cyclohexane, m- and p-phenylenedimethylene diisocyanates (m- and p-XDI), m- and p-tetramethylphenylenedimethylene-1,3- and -1,4-diisocyanates (m- and p-TMXDI), bis(1-isocyanate-1-methylethyl)naphthalene, dimer and trimer fatty acid isocyanates such as 3,6-bis(9-isocyanate-nonyl)-4,5-di-(1-heptenyl)cyclohexene (dimeryl diisocyanate) and α,α,α',α',α”,α”-hexamethyl-1,3,5-meta-trimethylphenyl triisocyanate.

[0136] Among these, MDI, TDI, HDI, and IPDI are preferred.

[0137] Suitable oligomers, polymers, and derivatives of the monomeric diisocyanates and triisocyanates described herein are particularly those derived from MDI, TDI, HDI, and IPDI. Of particular suitable commercially available grades, especially HDI diureas, are those... N 100 and N3200 (from Coves tro), HDB and HDB-LV (from Vencorex) and 24A-100 (from Asahi Kasei); HDI isocyanurate, for example N 3300, N 3600 and N 3790BA (all from Coves tro), HDT, HDT-LV, and HDT-LV2 (from Vencorex) TPA-100 and THA-100 (from Asahi Kasei) and HX (from Nippon Polyurethane); HDI isocyanate dimers, for example N3400 (from Coves tro); HDI iminooxydiazine dione, for example XP 2410 (from Covestro); HDI urea esters, for example VP LS2102 (from Coves tro); IPDI isocyanurate, for example, in solution form. Z 4470 (from Coves tro) or solid form T1890 / 100 (from Evonik); TDI oligomers, for example IL (from Coves tro); and TDI / HDI-based mixed isocyanurates, for example HL (from Coves tro). Also particularly suitable is the form of MDI that is liquid at room temperature (so-called "modified MDI"), which is a mixture of MDI and MDI derivatives, such especially MDI carbodiimide, MDI urea-ketimide, or MDI urethane, under trade names such as CD PF, PC (all from Coves tro) or M 143 (from Dow) is known to be a mixture of MDI and MDI homologues (polymer MDI or PMDI), which can be traded under names such as VL, VL50, VLR10, VL R20, VH 20N and VKS20F (all from Covestro) M 309, M 229 and M 580 (all from Dow) or M 10R (from BASF) was obtained. The oligomeric polyisocyanates mentioned above are actually 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.

[0138] The polyisocyanate is preferably selected from the following: MDI, TDI, HDI and IPDI, and oligomers, polymers and derivatives of the isocyanates described, and mixtures thereof.

[0139] The polyisocyanate preferably contains isocyanurate, iminooxydiazine dione, isocyanate dimer, diurea, urethane, carbodiimide, urea ketimide or oxadiazine trione groups.

[0140] MDI in liquid form at room temperature is particularly preferred as a polyisocyanate. These are especially referred to as polymeric MDI and MDI containing their oligomer or derivative moieties. In such liquid MDI forms, the content of MDI (= diphenylmethane 4,4'-, 2,4'- or 2,2'-diisocyanate and any desired mixture of these isomers) is particularly 50% to 95% by weight, especially 60% to 90% by weight.

[0141] Polymers of MDI and MDI grades that are liquid at room temperature and contain a portion of MDI carbodiimide or its adducts are particularly preferred as polyisocyanates.

[0142] Using these polyisocyanates, one obtains exceptionally good processing properties and exceptionally high strength.

[0143] The polyisocyanate of the second component B may contain portions of a polyurethane polymer having isocyanate groups. Either the second component may comprise a separately produced polyurethane polymer having isocyanate groups, or the polyisocyanate has been mixed with at least one polyol, particularly a polyether polyol, wherein the isocyanate groups are present in stoichiometric excess relative to the OH groups.

[0144] In the second component B of the composition of the present invention, polyisocyanate I is preferably present in an amount of 25%-100% by weight, especially 30%-90% by weight, more preferably 40%-75% by weight, based on the second component B.

[0145] Component A and / or component B further comprise at least one metal catalyst K capable of forming a thiocomplex for the reaction of the hydroxyl group with the isocyanate group. A suitable metal catalyst K is therefore any metal catalyst that can be used as a crosslinking catalyst in polyurethane chemistry and can simultaneously form a thiocomplex with a thiol in its presence.

[0146] The metal catalyst K is preferably present only in the first component A. This is beneficial for achieving better storage stability.

[0147] The amount of metal catalyst K in the first component A is preferably in the range of 0.05 wt% to 2.5 wt%, more preferably 0.1 wt% to 2.0 wt%, especially 0.2 wt% to 1.5 wt%, and more preferably 0.25 wt% to 1.0 wt%, based on the first component A.

[0148] When the catalyst is present in the second component B, the same preferred amounts as described above apply, but based on component B.

[0149] Based on the overall polyurethane composition, the amount of metal catalyst K is preferably in the range of 0.02 wt% to 1.0 wt%, more preferably 0.025 wt% to 0.8 wt%, especially 0.08 wt% to 0.6 wt%, and more preferably 0.1 wt% to 0.5 wt%, based on the overall polyurethane composition.

[0150] Examples of suitable metal catalysts are compounds of bismuth, zinc, tin, or zirconium, including complexes and salts of these metals.

[0151] The metal catalyst K preferably comprises a bismuth compound, especially a bismuth(III) compound. In addition to the desirable property that the catalyst can form thiocomplexes, bismuth compounds are advantageous due to their low acute toxicity.

[0152] A wide range of conventional bismuth catalysts can be used as bismuth compounds. Examples include bismuth carboxylate such as bismuth acetate, bismuth oleate, bismuth octanoate or bismuth neodecanoate, bismuth nitrate, bismuth halides such as bismuth bromide, bismuth chloride or bismuth iodide, bismuth sulfide, basic bismuth carboxylate such as bismuth neodecanoate, bismuth hypogallate or bismuth hyposalicylate, and mixtures thereof.

[0153] In a preferred embodiment, the metal catalyst K is a bismuth(III) complex containing at least one 8-hydroxyquinoline ligand. Such a complex is described in EP 1551895. Preferably, it is bismuth(III) carboxylate containing one molar equivalent of an 8-hydroxyquinoline ligand.

[0154] In another preferred embodiment, the metal catalyst K is a bismuth(III) complex containing at least one 1,3-ketoamide ligand. Such a complex is described in EP 2791153. Preferably, it is bismuth carboxylate(III) containing 1 to 3 molar equivalents of a 1,3-ketoamide ligand.

[0155] In addition to the components already mentioned, the polyurethane composition may contain other components known to those skilled in the art of two-component polyurethane chemistry. These may be present in only one component or in both components.

[0156] The preferred additional component is an inorganic or organic filler F, such as, in particular, naturally ground or precipitated calcium carbonate, optionally coated with fatty acids, especially stearic acid, baryte (heavy spar), talc, quartz powder, quartz sand, dolomite, wollastonite, kaolin, calcined kaolin, mica (potassium aluminum silicate), molecular sieve, alumina, aluminum hydroxide, magnesium hydroxide, silica (including fine silica from pyrolysis processes), industrially produced carbon black, graphite, metal powders such as aluminum, copper, iron, silver or steel powder, PVC powder or hollow spheres, and flame-retardant fillers such as hydroxides or hydrates, such as aluminum hydroxide or hydrates, preferably aluminum hydroxide.

[0157] Preferably, the composition of the present invention contains at least one filler F in the first component A, the second component B, or both components.

[0158] The addition of filler F is advantageous because it increases the strength of the cured polyurethane composition.

[0159] The polyurethane composition preferably contains at least one filler F selected from the following: calcium carbonate, carbon black, kaolin, barite, talc, quartz powder, dolomite, wollastonite, kaolin, calcined kaolin, and mica. Milled calcium carbonate, calcined kaolin, or carbon black is particularly preferred as filler F.

[0160] A mixture of different fillers can be used advantageously. The most preferred is a combination of ground calcium carbonate or calcined kaolin with carbon black.

[0161] The content of filler F in the composition is preferably in the range of 5% to 50% by weight, especially 10% to 40% by weight, more preferably 15% to 35% by weight, based on the overall composition.

[0162] The content of filler F in the first component A is preferably in the range of 10 wt%-60 wt%, more preferably 15 wt%-50 wt%, and especially 20 wt%-45 wt%, based on component A.

[0163] The content of filler F in the second component B is preferably in the range of 0 wt%-60 wt%, more preferably 10 wt%-50 wt%, and especially 10 wt%-45 wt%, based on the second component B.

[0164] Other components may also be present, especially solvents, plasticizers and / or compatibilizers, pigments, rheology modifiers such as, in particular, amorphous silica, desiccants such as, in particular, zeolites, adhesion promoters such as, in particular, organofunctional trialkoxysilanes, stabilizers against oxidation, heat, light and UV radiation, flame retardants, and surfactants, especially wetting agents and defoamers.

[0165] The polyurethane composition contains, preferably less than 0.5% by weight, and particularly less than 0.1% by weight, of a carboxylic acid, based on the overall composition. Any carboxylic acid ligands introduced via a metal catalyst are not included in the carboxylic acid herein.

[0166] The preferred polyurethane composition comprises a first component A, which is based on component A containing

[0167] -30% to 80% by weight, preferably 40% to 75% by weight, especially 50% to 70% by weight of polyol mixture P,

[0168] -0.1 wt% to 5 wt%, preferably 0.2 wt% to 2.5 wt%, especially 0.25 wt% to 1.0 wt% of compound T having at least one thiol group,

[0169] -0.05 wt% to 2.5 wt%, preferably 0.1 wt% to 2.0 wt%, especially 0.2 wt% to 1.5 wt%, more preferably 0.25 wt% to 1.0 wt% of the metal catalyst K, and

[0170] -10 wt% to 60 wt%, preferably 15 wt% to 50 wt%, especially 20 wt% to 45 wt% of filler F,

[0171] And other optional ingredients.

[0172] The same or another preferred polyurethane composition comprises a second component B, which is based on component B comprising

[0173] -25% to 100% by weight, preferably 30% to 75% by weight, especially 40% to 60% by weight of polyisocyanate I,

[0174] -0% to 60% by weight, preferably 10% to 50% by weight, especially 20% to 40% by weight of polyols, with hydrophilic polyol P2 being preferred.

[0175] -0% to 60% by weight, preferably 10% to 50% by weight, especially 10% to 45% by weight of filler F,

[0176] And other optional ingredients.

[0177] Advantageously, the first component A and the second component B are formulated such that their mixing ratio, in parts by volume or weight, is in the range of 10:1 to 1:10, preferably 5:1 to 1:5, and especially 2:1 to 1:2.

[0178] In the polyurethane blend composition, the ratio of the number of isocyanate groups to the number of isocyanate-reactive groups before curing is preferably in the range of about 1.2-1, more preferably 1.15-1.05. However, although not generally preferred, the proportion of isocyanate groups may also be lower than stoichiometry relative to the isocyanate-reactive groups.

[0179] The two components, A and B, are produced separately and preferably with moisture removed. Each component is typically stored in a separate container. Other components of the polyurethane composition may be present as components of the first or second component, with other components reactive to isocyanate groups preferably being components of the first component. Suitable containers for storing the components are, in particular, drums, roll-on / roll-off boxes, bags, barrels, cans, cylinders, or tubes. The components are storage stable, meaning they can be stored for several months to a year or longer before use without any change in their individual properties to the extent relevant to their use.

[0180] The two components are stored separately before the composition is mixed and are only mixed with each other upon or immediately before use. They are advantageously contained in a package consisting of two separate chambers.

[0181] In another aspect, the present invention comprises a package consisting of a package having two separate chambers, each containing a first component A and a second component B of the composition.

[0182] Mixing is typically carried out using a static mixer or by means of a dynamic mixer. During mixing, care must be taken to ensure that the two components are mixed as uniformly as possible. Incomplete mixing will result in localized deviations from the optimal mixing ratio, which can lead to deterioration of mechanical properties.

[0183] When component A comes into contact with component B, curing begins through a chemical reaction. This includes the reaction of hydroxyl groups and any other substances present that are reactive with isocyanate groups with the isocyanate groups. Excess isocyanate groups react primarily with moisture. The result of these reactions is the curing of the polyurethane composition to produce a solid material. This method is also known as crosslinking.

[0184] The reaction thus also provides a cured polyurethane composition obtained by curing a polyurethane composition as described in this document.

[0185] The two-component polyurethane composition is advantageously used as a matrix for structural adhesives, castables, or composite materials.

[0186] The present invention also relates to a method for bonding a first substrate and a second substrate, comprising the following steps:

[0187] - Mix the first and second components described above.

[0188] - Apply the mixed polyurethane composition to at least one substrate surface to be bonded.

[0189] -The substrate to be bonded during the applicable period,

[0190] - Cured polyurethane composition.

[0191] These two substrates can be made of the same material or different materials.

[0192] The present invention further relates to a method for filling the joint and gap between two substrates, comprising the following steps:

[0193] - Mix the first and second components described above.

[0194] - Apply the mixed polyurethane composition to the joints or gaps.

[0195] - Cured polyurethane composition.

[0196] In these methods of bonding or filling joints and gaps, a suitable substrate is particularly important.

[0197] - Glass, glass ceramics, glass mineral fiber mats;

[0198] - Metals and alloys such as aluminum, iron, steel and non-ferrous metals, as well as surface-treated metals and alloys such as zinc-plated or chromium-plated metals;

[0199] - Coated and painted substrates, such as powder-coated metals or alloys and painted metal sheets;

[0200] - Plastics, such as polyvinyl chloride (rigid and flexible PVC), acrylonitrile-butadiene-styrene copolymer (ABS), polycarbonate (PC), polyamide (PA), poly(methyl methacrylate) (PMMA), polyester, epoxy resin, especially epoxy thermosetting materials, polyurethane (PUR), polyoxymethylene (POM), polyolefin (PO), polyethylene (PE) or polypropylene (PP), ethylene / propylene copolymer (EPM) and ethylene / propylene / diene terpolymer (EPDM), wherein the plastics may preferably be surface treated by plasma, corona or flame;

[0201] - Fiber-reinforced plastics, such as carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GFRP), and sheet molding compounds (SMC);

[0202] - Wood, wood-based materials bonded with resins, such as phenolic resins, melamine resins or epoxy resins, resin-fabric composites, and other so-called polymer composites; and

[0203] - Concrete, mortar, brick, plaster and natural stone such as granite, limestone, gravel or marble.

[0204] In these methods, one or both of the substrates are preferably metals or glass ceramics or glass or glass fiber reinforced plastics or carbon fiber reinforced plastics or epoxy thermosetting materials.

[0205] If necessary, the substrate may be pretreated before applying the composition. Such pretreatment specifically includes physical and / or chemical cleaning methods and the application of an adhesion promoter, adhesion promoter solution, or primer.

[0206] The bonding method provides an article in which two substrates are bonded together with a composition.

[0207] The articles, in particular lightweight sandwich elements, building structures such as bridges, industrial products or consumer goods, especially windows, rotating blades of wind turbines, or means of transport, especially vehicles, preferably automobiles, buses, trucks, rail vehicles or ships, or airplanes or helicopters, or installable parts of such articles.

[0208] The polyurethane composition is characterized by high strength and elasticity, which remain highly constant over a wide temperature range from -35°C to 85°C, and by excellent, largely temperature-independent, adhesion to metallic substrates. Due to these properties, it is particularly well-suited as a structural adhesive for bonding under outdoor stress at ambient temperatures.

[0209] Therefore, the present invention further provides the use of the polyurethane composition as a structural adhesive for bonding two substrates.

[0210] The polyurethane composition is also advantageously used as a casting material, especially as a casting material for filling gaps and joints, as a ballast compensation compound for repair purposes, or for protecting electronic components.

[0211] Polyurethane compositions are further preferred for use as casting materials, especially electrocasting materials. In another aspect, the invention therefore includes the use of two-component polyurethane compositions as casting materials, particularly as electrocasting materials.

[0212] In another aspect, the present invention therefore includes a method for filling joints and gaps in a substrate, comprising the following steps:

[0213] a) Mix the first and second components of the two-component polyurethane composition as described above.

[0214] b) Apply the mixed polyurethane composition to the joint to be traversed between two substrates or to the gap to be filled on the surface of the substrates.

[0215] c) Polyurethane composition in cured joints or gaps.

[0216] Particularly suitable substrates are metals, plastics, wood, glass, ceramics, and fiber-reinforced plastics, especially metals and fiber-reinforced plastics. In another aspect, the invention therefore also includes filled articles that have been filled according to the methods described above.

[0217] The polyurethane composition is further preferably used as a matrix in the composite material. The polyurethane composition here acts as a binder embedded in fibers or other reinforcing structures. In another aspect, the invention therefore includes the use of a two-component polyurethane composition as a matrix in a composite material. Example

[0218] The substances used:

[0219]

[0220]

[0221] Table 1: Substances Used

[0222] Preparation of polyurethane compositions

[0223] For each composition, the components of the first component A specified in the table are processed into a homogeneous paste in a specified amount (parts by weight or % by weight) and stored by means of a vacuum dissolver that removes moisture. The components of the second component B specified in the table are processed and stored in the same manner. Then, by means of... (DAC 150FV, Hauschild) The two components were processed into a uniform paste for 30 seconds and immediately tested as follows:

[0224] To determine the mechanical properties, the adhesive was shaped into dumbbells according to ISO 527 Part 2 1B and stored / cured at 23°C and 50% RH (relative humidity) for the times specified in the table (1 day and 7 days), and then at 90°C for 7 days. After a 24-hour conditioning period at 23°C and 50% RH, the modulus of elasticity, tensile strength, and elongation at break of the test specimens thus prepared were measured on a Zwick Z020 tensile testing machine at 23°C and 50% RH and a test speed of 10 mm / min, according to DIN EN ISO 527.

[0225] To measure tensile shear strength, various test specimens were produced. In each case, an adhesive was applied for 1 minute, with a layer thickness of 2 mm and an overlap of 15 × 45 mm, between two heptane-degreased cathode electrocoated steel plates after the mixing time. The test specimens were stored / cured at 23°C (“cool conditions”) for 24 h. Some samples were then additionally stored / cured for 10 days under hot and humid conditions (40°C and 100% relative humidity). After a 24-hour conditioning period at 23°C and 50% RH, the tensile shear strength was determined according to DIN EN 1465.

[0226] On an MCR 302 parallel plate rheometer (Anton Paar) with a plate diameter of 25 mm and a plate spacing of 1 mm, the rheometer was used for 10 seconds. -1 Viscosity was measured at a frequency of 20°C and a temperature of 20°C. This was done by first manually mixing the two components in a beaker for 30 seconds using a spatula, and then immediately applying them to a plate for measurement.

[0227] The measurement results are given in the table.

[0228] In the table, compositions according to the invention are designated as “I” (I-1 to I-11) and non-invention reference compositions are designated as “R” (R-1 to R-4).

[0229]

[0230] Table 2. Example compositions R-1, R-2, I-1 and I-2

[0231]

[0232]

[0233] Table 3. Example compositions R-3, R-4, I-3, I-4 and I-5

[0234] The viscosity measurements in Tables 2 to 5 show that the compositions of the present invention continue to have low viscosity for a relatively long time (time t1), but then cure very quickly (times t2 and t3, especially the difference between times t2 and t3).

[0235] The subtraction of time t3 and time t2 indicates the curing rate. The smaller this value, the faster the composition cures. To adequately represent the curing rate according to the invention, the value of t3 minus t2 should be less than 5, preferably less than 4.5. In a particularly preferred embodiment, the value of t3 minus t2 is less than 2, especially less than 1.5.

[0236]

[0237] Table 4. Example compositions I-6 to I-9

[0238]

[0239] Table 5. Example compositions I-10 and I-11

[0240]

[0241] Table 6. Measurement values ​​“n / m” for example compositions I-10 and I-11 indicate that the value was not measured.

[0242] Table 5 shows that for Experiment I-10, the applied temperature also affects the curing rate and pot life. This means that the application and curing of the composition can also be further affected by the applied temperature.

[0243] Table 6 shows that the use of diol P3 (in this case, 1,4-butanediol in Examples I-11) has a significant positive effect on the mechanical properties of the compositions of the present invention.

Claims

1. Polyurethane composition consisting of a first component A and a second component B, wherein - the first component A comprises - between 30 and 99 wt.-%, based on component A, of a polyol mixture P, which comprises - 100 parts by weight of at least one hydrophobic polyol P1 which is a polybutadiene polyol, a polyester polyol based on dimer fatty acids or a mixture of said polyols, - 10 to 75 parts by weight of at least one hydrophilic polyol P2 which is a polyether polyol having propylene glycol repeat units in the polymer backbone, - 0 to 25 parts by weight of at least one diol P3 having two hydroxyl groups connected by a C2-C9 carbon chain, and - at least one compound T having at least one thiol group, which comprises a polythiol compound having 2 to 6 thiol groups; and - the second component B comprises - at least one polyisocyanate I; wherein one of the two components further comprises at least one metal catalyst K capable of forming a thio complex for the reaction of hydroxyl groups with isocyanate groups, and the molar ratio of all thiol groups in the at least one compound T to all metal atoms in the at least one metal catalyst K is between 1 : 1 and 250:

1.

2. Polyurethane composition according to claim 1, characterized in that the metal catalyst K comprises a bismuth (III) compound.

3. Polyurethane composition according to claim 2, characterized in that the bismuth (III) compound is a bismuth (III) carboxylate.

4. Polyurethane composition according to claim 2, characterized in that the bismuth (III) compound further contains an 8-hydroxyquinoline ligand or a 1,3-ketoamide ligand.

5. Polyurethane composition according to claim 1 or 2, characterized in that the diol P3 is a linear aliphatic diol having two primary hydroxyl groups connected by a C4-C9 carbon chain.

6. Polyurethane composition according to claim 1 or 2, characterized in that the diol P3 is selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and 1,9-nonanediol.

7. Polyurethane composition according to claim 1, characterized in that the at least one compound T is selected from the group consisting of ethylene glycol di(3-mercaptopropionate), ethylene glycol dimercaptoacetate and dipentaerythritol hexa(3-mercaptopropionate).

8. Polyurethane composition according to claim 1 or 2, characterized in that the molar ratio of all thiol groups in the at least one compound T to all metal atoms in the at least one metal catalyst K is between 5: 1 and 100:

1.

9. Polyurethane composition according to claim 1 or 2, characterized in that the metal catalyst K is comprised in the first component A.

10. Polyurethane composition according to claim 1 or 2, characterized in that the hydrophilic polyol P2 is a polyether polyol having an average OH functionality of at least 2.5 and having propylene glycol repeat units in the polymer backbone.

11. Polyurethane composition according to claim 1 or 2, characterized in that the polyisocyanate I is diphenylmethane-4,4'-, -2,4'- or -2,2'-diisocyanate in liquid form at room temperature, or any desired mixture of these isomeric MDI in the form of polymeric MDI or MDI with oligomer or derivative moieties.

12. Polyurethane composition according to claim 11, characterized in that the oligomer or derivative is a carbodiimide.

13. Polyurethane composition according to claim 1 or 2, characterized in that the second component B comprises a polyurethane polymer with isocyanate groups.

14. Polyurethane composition according to claim 1, characterized in that the polyol P1 has an average OH functionality of between 2 and 2.

5.

15. Process for bonding a first substrate with a second substrate, comprising the following steps: - mixing the first component and the second component of the polyurethane composition according to any one of claims 1 to 14, - applying the mixed polyurethane composition to the surface of at least one of the substrates to be bonded, - bonding the substrates to be bonded within the open time, - curing the polyurethane composition.

16. Article obtained by the process according to claim 15.

17. Use of the polyurethane composition according to any one of claims 1 to 14 as a structural adhesive for bonding two substrates or as a matrix in a composite material.

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