Linear isocyanate group-containing polymer

Abstract

The present invention relates to a linear isocyanate group-containing polymer having an NCO content in the range of 0.3 to 1.5 wt.% and a diisocyanate monomer content of 0.5 wt.% or less, characterized in that the polymer is obtained by reacting at least one aromatic diisocyanate monomer with a polyether diol having an OH value in the range of 5 to 21 mg KOH / g in an NCO / OH ratio of at least 5 / 1, followed by removal of most of the diisocyanate monomer by a suitable separation process. It also relates to a moisture-curable polyurethane composition containing the polymer and having a diisocyanate monomer content of less than 0.1 wt.%. The polymer according to the present invention enables the production of elastic adhesives having high elongation, surprisingly high strength, and surprisingly good adhesion to plastic substrates.

Description

[Technical Field]

[0001] The present invention relates to polymers having low monomer levels for moisture-curable polyurethane compositions and their use as elastic adhesives with good adhesion to plastic substrates. [Background technology]

[0002] Polyurethane compositions that crosslink and cure to elastomers by reaction of isocyanate groups with moisture or water are used particularly in the construction and manufacturing industries as elastic adhesives or sealants, for example, to join parts or fill joints in assemblies. Their adhesive and elastic properties allow them to gently dampen and buffer forces acting on substrates caused, for example, by vibration or temperature changes.

[0003] Such polyurethane compositions contain a polymer containing isocyanate groups as a binder, which is prepared by reacting diisocyanate monomers with polyols. Due to chain extension reactions, the resulting polymers typically have residual diisocyanate monomer contents ranging from 1% to 3% by weight. Diisocyanate monomers can be harmful to health. In particular, formulations containing diisocyanate monomers at concentrations greater than 0.1% by weight must provide hazard symbols and warning messages on labels and data sheets, and may be subject to restrictions on sale and use in some countries. Therefore, interest is growing in polyurethane compositions with low monomer contents, particularly below 0.1% by weight. An attractive route to isocyanate-containing polymers with low diisocyanate monomer contents is to use an excess of diisocyanate monomer in the polymer preparation and then remove most of the unconverted diisocyanate monomer by distillation. This route is particularly easy to implement with low-molecular-weight, and therefore volatile, diisocyanate monomers, such as hexanediisocyanate. However, the polymers on which it is based result in slow curing and poor mechanical strength of the product.

[0004] Polymers based on diphenylmethane 4,4'-diisocyanate (4,4'-MDI) offer high strength combined with high elasticity, but production is quite challenging due to the low volatility of 4,4'-MDI when distilling off excess monomer.

[0005] Elastic adhesives for bonding plastic substrates are increasingly needed in the industry, for example, for bonding headlamp housings or panoramic roofs in automobiles, organic glass in ships or trains, or various parts of trailers. The adhesives herein cure quickly and reliably, are highly elastic while having high strength, and have high bond strength even under heat and water stress without complex pre-treatment of the plastic substrate. However, adhesives based on polymers with low monomer levels show weaknesses in enhancing adhesion to plastic substrates, especially since they are substantially devoid of diisocyanate monomers. Summary of the Invention [Problem to be solved by the invention]

[0006] It is therefore an object of the present invention to provide a polymer with a low content of diisocyanate monomers that allows for elastic adhesives with reliable cure and high strength, no labeling obligations, and that significantly improve their adhesion to plastic substrates. [Means for solving the problem]

[0007] This object is achieved by the linear polymer described in claim 1. The polymer has an NCO content ranging from 0.3% to 1.5% by weight and is based on an aromatic diisocyanate monomer, particularly diphenylmethane 4,4'-diisocyanate, and a polyether diol having an OH value ranging from 5 to 21 mg KOH / g. The polymer of the present invention is a linear, long-chain polymer with a low content of diisocyanate monomer. It is liquid at room temperature, has a relatively low viscosity, and has excellent storage stability when moisture is excluded. It enables elastic adhesives with an attractive EHS classification and surprisingly good adhesion to plastic substrates, such as PVC, PMMA, or polycarbonate, even under heat and water stress. Particularly surprising herein is the fact that the polymer of the present invention imparts to the adhesive excellent mechanical properties, particularly high strength (tensile strength and modulus), which were not expected from such long-chain linear polymers. Compared to polymers based on short-chain polyether diols, the polymer of the present invention achieves significantly better adhesion to plastic substrates with comparable mechanical properties.

[0008] Further aspects of the invention are the subject matter of further independent claims. Particularly preferred embodiments of the invention are the subject matter of the dependent claims. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention provides a linear polymer containing an isocyanate group and having an NCO content in the range of 0.3% by weight to 1.5% by weight and a diisocyanate monomer content of 0.5% by weight or less, 1. A process for producing a polyether diol comprising the steps of: reacting at least one aromatic diisocyanate monomer with a polyether diol having an OH value in the range of 5 to 21 mg KOH / g in an NCO / OH ratio of at least 5 / 1; and then removing most of the aromatic diisocyanate monomer by a suitable separation method. A linear polymer is provided.

[0010] "Diisocyanate monomer" means an organic compound having two isocyanate groups separated by a divalent hydrocarbyl group having from 4 to 15 carbon atoms.

[0011] By "aromatic" isocyanate groups is meant groups that are directly bonded to aromatic carbon atoms. Isocyanates that have predominantly aromatic isocyanate groups are accordingly called "aromatic isocyanates."

[0012] By "aliphatic" isocyanate group is meant a group that is directly bonded to an aliphatic or alicyclic carbon atom. Isocyanates having predominantly aliphatic isocyanate groups are accordingly called "aliphatic isocyanates."

[0013] The term "aromatic diisocyanate monomer" means a diisocyanate monomer having an aromatic isocyanate group.

[0014] "NCO content" means the content of isocyanate groups in % by weight.

[0015] "Molecular weight" means the molar mass (g / mol) of a molecule or molecular residue. "Average molecular weight" means the average molecular weight (M n ) It is determined by gel permeation chromatography (GPC) against polystyrene as a standard.

[0016] A substance or composition is said to be "storage-stable" or "storable" if it can be stored at room temperature in a suitable container for an extended period of time, usually at least 3 months, preferably up to 6 months or more, without this storage resulting in any change in its application or use characteristics to an extent relevant to its use.

[0017] "Plastic" means an organic material based on macromolecules.

[0018] "Room temperature" means a temperature of 23°C.

[0019] All industry standards and criteria mentioned herein relate to the version in effect on the date of first filing.

[0020] Weight percentage, abbreviated as wt. %, unless otherwise specified, means the ratio (by mass) of a component of a composition or molecule relative to the entire composition or molecule. The terms "mass" and "weight" are used interchangeably herein.

[0021] The polymers of the present invention containing isocyanate groups may also be referred to as prepolymers.

[0022] The polymers of the invention preferably have an NCO content in the range of 0.5% to 1.3% by weight, in particular 0.7% to 1.1% by weight.

[0023] More preferably, the polymer has an NCO content in the range of 0.8% to 1.1% by weight, especially 0.9% to 1.1% by weight. Such polymers allow for particularly storage-stable compositions with very good adhesion to plastic substrates. The polymers of the present invention preferably have a diisocyanate monomer content of 0.3% by weight or less, especially 0.2% by weight or less. Such polymers are particularly suitable for the production of moisture-curable polyurethane compositions having a diisocyanate monomer content of less than 0.1% by weight, which can be handled safely even without special safety precautions and can therefore be sold in many countries without hazard labels.

[0024] Suitable aromatic diisocyanate monomers are in particular diphenylmethane 4,4'-diisocyanate, optionally with a fraction of diphenylmethane 2,4'- and / or 2,2'-diisocyanate (MDI), its mixture with tolylene 2,4-diisocyanate or tolylene 2,6-diisocyanate (TDI), phenylene 1,4-diisocyanate (PDI), 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene 1,5-diisocyanate (NDI) or 3,3'-dimethyl-4,4'-diisocyanatodiphenyl (TODI). Among these, diphenylmethane 4,4'-diisocyanate, tolylene 2,4-diisocyanate or phenylene 1,4-diisocyanate are preferred.

[0025] A particularly preferred aromatic diisocyanate monomer is diphenylmethane 4,4'-diisocyanate (4,4'-MDI). This 4,4'-MDI is a quality containing only a small proportion of diphenylmethane 2,4'- and / or 2,2'-diisocyanate and is solid at room temperature. This allows for particularly rapid curing and particularly high strength adhesives, combined with high elongation and elasticity. 4,4'-MDI is preferably distilled and has a purity of at least 95%, particularly at least 97.5%. Commercially available diphenylmethane 4,4'-diisocyanate of this quality is, for example, Desmodur® 44MC (Covestro), or Lupranat® MRS or ME (BASF), or Suprasec® 1400 (Huntsman).

[0026] The polyether diol preferably contains repeating units selected from the group consisting of 1,2-ethyleneoxy, 1,2-propyleneoxy, 1,3-propyleneoxy, 1,2-butyleneoxy, and 1,4-butyleneoxy. 1,2-propyleneoxy groups with or without a specific proportion of 1,2-ethyleneoxy groups are preferred.

[0027] More specifically, the polyether diol contains 80 to 100% by weight of 1,2-propyleneoxy groups and 0 to 20% by weight of 1,2-ethyleneoxy groups. When the polyether diol contains 1,2-ethyleneoxy groups, the 1,2-propyleneoxy groups and the 1,2-ethyleneoxy groups preferably form uniform blocks, with the poly(1,2-ethyleneoxy) blocks at the ends of the chains.

[0028] The polyether diol preferably has an OH number in the range of 6 to 19 mg KOH / g, in particular 9 to 14 mg KOH / g, most preferably 12 to 14 mg KOH / g.

[0029] The polyether diol preferably has an average molecular weight M in the range of 5,500 to 20,000 g / mol, more preferably 6,000 to 18,000 g / mol, especially 8,000 to 12,000 g / mol, most preferably 8,000 to 9,000 g / mol. n It has.

[0030] The polyetherdiol preferably has an average OH functionality of at least 1.8, in particular at least 1.9. As a result of its production, commercially available polyetherdiols contain a certain content of monools, and as a result, the average OH functionality is usually slightly below 2.

[0031] The polyether diol preferably has an unsaturation level of less than 0.02 meq / g, in particular less than 0.01 meq / g, measured according to ASTM D-2849-69. Polyether diols having an unsaturation level of less than 0.01 meq / g are particularly prepared using catalysts known as double metal cyanide complex catalysts (DMC catalysts).

[0032] The polyether diol more preferably has an OH number in the range of 6 to 19 mg KOH / g, preferably 9 to 14 mg KOH / g, most preferably 12 to 14 mg KOH / g and an average OH functionality of at least 1.9.

[0033] Suitable polyether diols are commercially available, for example, as Acclaim® Polyol 8200N, Acclaim® Polyol 12200N, Acclaim® Polyol 18200N (all Covestro) or Preminol® S4013F (Asahi Glass Co., Ltd.).

[0034] Preferably, the polymers of the present invention have an average molecular weight M in the range of 6,000 to 40,000 g / mol as determined by gel permeation chromatography (GPC) against polystyrene as a standard using tetrahydrofuran as the mobile phase and a refractive index detector. n More preferably, the average molecular weight M n is in the range of 8,000 to 30,000 g / mol, particularly 8,000 to 15,000 g / mol.

[0035] The polymers of the present invention are obtained by reacting at least one aromatic diisocyanate monomer with a polyether diol in an NCO / OH ratio of at least 5 / 1. The NCO / OH ratio is preferably in the range of 5 / 1 to 20 / 1, more preferably in the range of 6 / 1 to 15 / 1, and especially in the range of 7 / 1 to 13 / 1. The reaction is preferably carried out at a temperature in the range of 20 to 160°C, especially 40 to 140°C, optionally in the presence of a suitable catalyst, with the exclusion of water. After the reaction, the diisocyanate monomer remaining in the reaction mixture is removed to the stated residual content using a suitable separation method.

[0036] A preferred separation method is a distillation method, in particular thin film distillation or short path distillation, preferably applying reduced pressure.

[0037] Particularly preferred is a multistage process in which the aromatic diisocyanate monomer is removed in a short-path evaporator using a jacket temperature in the range of 120-200°C and a pressure of 0.001-0.5 mbar. In the case of 4,4'-MDI, which is the preferred aromatic diisocyanate monomer, the distillative removal is particularly demanding. For example, it must be ensured that the condensate does not solidify and block the system. It is preferred to operate at a jacket temperature in the range of 160-200°C at 0.001-0.5 mbar and condense the removed monomer at a temperature in the range of 40-60°C.

[0038] It is preferred to react the aromatic diisocyanate monomer with the polyether diol and then remove most of the diisocyanate monomer remaining in the reaction mixture without using a solvent or entraining agent. It is preferred to subsequently recycle the aromatic diisocyanate monomer removed after the reaction, i.e., to use it again to prepare a polymer containing isocyanate groups.

[0039] Most preferably, the isocyanate group-containing polymer has an NCO content in the range of 0.5% to 1.3% by weight and a diisocyanate monomer content of 0.3% by weight or less. Such polymers are particularly suitable for elastic adhesives with good adhesion to plastic substrates, good mechanical properties, and good EHS classification.

[0040] The polymer of the present invention is liquid at room temperature and has a relatively low viscosity. It preferably has a viscosity of 80 Pa·s or less, particularly 70 Pa·s or less, and more preferably 60 Pa·s or less at 20°C. Viscosity is measured herein as a viscosity of 10 s using a cone and plate viscometer. -1 is determined by the shear rate.

[0041] In this reaction, the OH groups of the polyether diol react with the isocyanate groups of the aromatic diisocyanate monomer. This also results in a reaction called chain extension, in that there is a reaction of the OH groups and / or isocyanate groups of the reaction product of the diol and the diisocyanate monomer. The higher the NCO / OH ratio selected, the lower the level of chain extension that occurs, the lower the polydispersity and therefore the lower the viscosity of the resulting polymer. A measure of chain extension is the average molecular weight of the polymer or the width and distribution of the peaks in GPC analysis. A further measure is the effective NCO content of the polymer from which the monomers have been removed, relative to the theoretical NCO content calculated from the reaction of all OH groups with the aromatic diisocyanate monomer.

[0042] The polymers of the present invention preferably contain only a low content of chain-extended components. The NCO content in the polymers of the present invention is preferably at least 90%, in particular at least 95%, of the theoretical NCO content calculated from the addition of one mole of diisocyanate monomer per mole of OH groups of the polyether diol.

[0043] The polymers of the present invention have low viscosity, contain low diisocyanate monomer contents, and are very storage stable when moisture is excluded. They are particularly suitable for producing elastic adhesives that have rapid cure, high strength, high elongation, and good adhesion, especially to plastic substrates.

[0044] The present invention further provides a moisture-curable polyurethane composition having a diisocyanate monomer content of less than 0.1% by weight and comprising an isocyanate group-containing linear polymer of the present invention.

[0045] The moisture-curable polyurethane composition preferably has a content of the polymer of the present invention in the range of 5% to 80% by weight, in particular 10% to 70% by weight, more preferably 20% to 60% by weight, based on the total composition.

[0046] In addition to the polymer of the present invention, the moisture-curable polyurethane composition may contain at least one additional polymer containing isocyanate groups that does not correspond to the polymer of the present invention.Suitable additional polymers containing isocyanate groups are conventionally prepared polymers or other polymers from which monomers have been removed.Additional polymers containing aromatic isocyanate groups are suitable, but polymers containing aliphatic isocyanate groups are also suitable.

[0047] Further suitable polymers containing isocyanate groups can be obtained by reacting at least one polyol with a superstoichiometric amount of at least one diisocyanate. This reaction is preferably carried out at a temperature ranging from 20 to 160°C, in particular from 40 to 140°C, optionally in the presence of a suitable catalyst, with the exclusion of water. The NCO / OH ratio is preferably in the range of 1.3 / 1 to 10 / 1. Diisocyanate monomer remaining in the reaction mixture after the reaction of the OH groups can be removed, in particular, by distillation. If the diisocyanate monomer is removed from the polymer by distillation, the NCO / OH ratio in the reaction is preferably in the range of 3 / 1 to 10 / 1, and the resulting polymer containing isocyanate groups after distillation preferably contains not more than 0.5% by weight, more preferably not more than 0.3% by weight, of diisocyanate monomer. If the diisocyanate monomer is removed from the polymer, the NCO / OH ratio in the reaction is preferably in the range of 1.3 / 1 to 2.5 / 1. Such polymers in particular contain not more than 3.5% by weight, preferably not more than 2% by weight, of diisocyanate monomers.

[0048] Preferred diisocyanate monomers are the above-mentioned aromatic diisocyanates, as well as aliphatic or cycloaliphatic diisocyanates, in particular MDI, TDI, hexane 1,6-diisocyanate (HDI), isophorone diisocyanate (IPDI) or perhydro(diphenylmethane 2,4'- or 4,4'-diisocyanate) (HMDI) or mixtures thereof, with 4,4'-MDI, TDI or IPDI being particularly preferred.

[0049] Suitable polyols are commercially available polyols or mixtures thereof, in particular - polyether polyols, in particular polyoxyalkylenediols and / or polyoxyalkylenetriols, in particular ethylene oxide, or 1,2-propylene oxide, or 1,2- or 2,3-butylene oxide, or oxetane, or tetrahydrofuran, or mixtures thereof, which are polymerized with an initiator molecule having two or three active hydrogen atoms, in particular water, ammonia, or compounds having two or more OH or NH groups, such as ethane-1,2-diol, propane-1,2- or -1,3-diol, neopentyl glycol, The polymerization may be carried out using ethylene glycol, diethylene glycol, triethylene glycol, isomeric dipropylene glycols or tripropylene glycols, isomeric butanediols, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, cyclohexane-1,3- or -1,4-methanol, bisphenol A, hydrogenated bisphenol A, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, or aniline, or mixtures of the above compounds. Similarly suitable are polyether polyols having dispersed polymer particles, particularly styrene / acrylonitrile (SAN) particles or polyurea or polyhydrazodicarbonamide (PHD) particles. Preferred polyether polyols are polyoxypropylene diols or triols, or what are called ethylene oxide-terminated (EO-capped or EO-tipped) polyoxypropylene diols or triols. The latter are obtained in particular by further alkoxylation with ethylene oxide of polyoxypropylene diols or triols resulting from a polypropoxylation reaction, resulting in primary hydroxyl groups.

[0050] Preferred polyether polyols have an unsaturation level of less than 0.02 meq / g, especially less than 0.01 meq / g. - polyester polyols, also called oligoesterols, which are prepared by known processes, in particular by polycondensation of di- or polyhydric alcohols with hydroxycarboxylic acids or lactones or with aliphatic and / or aromatic polycarboxylic acids. Preference is given to polyesterdiols from the reaction of dihydric alcohols, such as in particular ethane-1,2-diol, diethylene glycol, propane-1,2-diol, dipropylene glycol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, neopentyl glycol, glycerol, 1,1,1-trimethylolpropane or mixtures of the above alcohols, with organic dicarboxylic acids or their anhydrides or esters, such as in particular succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexane-1,2-dicarboxylic acid, cyclohexane-1,3-dicarboxylic acid or -1,4-dicarboxylic acid or mixtures of the above acids, or polyesterpolyols formed from lactones, such as in particular ε-caprolactone. Particularly preferred are polyester polyols formed from adipic acid, or sebacic acid, or dodecanedicarboxylic acid, and hexanediol or neopentyl glycol. Polycarbonate polyols obtainable, for example, by reacting the alcohols mentioned above, used to form the polyester polyols, with dialkyl carbonates, diaryl carbonates or phosgene. Block copolymers, in particular polyether polyester polyols, having at least two different blocks carrying at least two OH groups and having a polyether, polyester and / or polycarbonate structure of the type mentioned above. - Polyacrylate or polymethacrylate polyols. - polyhydroxy-functional fats or oils, such as natural fats and oils, in particular castor oil; or polyols obtained by chemical modification of natural fats and oils, known as oleochemical polyols, such as epoxy polyesters or epoxy polyethers obtained by epoxidation of unsaturated oils followed by ring-opening with carboxylic acids or alcohols, or polyols obtained by hydroformylation and hydrogenation of unsaturated oils; or polyols obtained from natural fats and oils by degradation processes such as alcoholysis or ozonolysis followed by chemical coupling, for example by transesterification or dimerization, of the degradation products thus obtained or their derivatives. Suitable degradation products of natural fats and oils are in particular fatty acids and fatty alcohols, and also fatty acid esters, in particular methyl esters (FAME), which can be derivatized, for example, by hydroformylation and hydrogenation, to give hydroxy fatty acid esters. Polyhydrocarbon polyols, also known as oligohydrocarbonols, such as, in particular, polyhydroxy-functional polyolefins, polyisobutylene, polyisoprene; polyhydroxy-functional ethylene / propylene, ethylene / butylene, or ethylene / propylene / diene copolymers, such as those produced by Kraton Polymers; polyhydroxy-functional polymers of dienes, in particular 1,3-butadiene, which may in particular be prepared by anionic polymerization; polyhydroxy-functional copolymers of dienes, in particular 1,3-butadiene, or diene mixtures, with vinyl monomers, such as styrene, acrylonitrile, vinyl chloride, vinyl acetate, vinyl alcohol, isobutylene, or isoprene, in particular polyhydroxy-functional acrylonitrile / butadiene copolymers and carboxyl-terminated acrylonitrile / butadiene copolymers, which may be prepared from epoxides or amino alcohols (available, for example, under the names Hypro® CTBN, CTBNX, or ETBN, from Emerald Performance Materials); or hydrogenated polyhydroxy-functional polymers or copolymers of dienes. Mixtures of polyols are particularly suitable.

[0051] Polyols and / or polyether triols having an OH number of at least 22 mg KOH / g are preferred.

[0052] To prepare polymers containing isocyanate groups, difunctional or polyfunctional alcohols are used, in particular ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, 2-methylpropane-1,3-diol, butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, pentane-1,3-diol, pentane-1,5-diol, 3-methylpentane-1,5-diol, neopentyl glycol, dibromoneopentyl glycol, hexane-1,2-diol, hexane-1,6-diol, heptane-1,7-diol, octane-1,2-diol, octane-1,8-diol, 2-ethylhexane-1,3-diol, It is also possible to use fractions of cyclohexane-1,3-methanol or -1,4-methanol, ethoxylated bisphenol A, propoxylated bisphenol A, cyclohexanediol, hydrogenated bisphenol A, dimeric fatty acid alcohols, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, pentaerythritol, sugar alcohols, such as in particular xylitol, sorbitol or mannitol or in particular sugars, such as sucrose, or alkoxylated derivatives of the aforementioned alcohols or mixtures of the aforementioned alcohols.

[0053] Preferably, the moisture-curable polyurethane composition has a content of the polymer of the invention of at least 25% by weight, preferably at least 40% by weight, in particular at least 60% by weight, based on the total amount of polymers containing isocyanate groups in the composition.

[0054] Preferably, the moisture-curable polyurethane composition further contains at least one branched component containing isocyanate groups and having an average NCO functionality greater than 2. Together with the polymer of the present invention, this allows for good mechanical strength and thermal stability combined with good adhesion to plastic substrates.

[0055] Preferably, the branched component containing isocyanate groups is selected from the group consisting of diisocyanate oligomers and branched polymers containing isocyanate groups.

[0056] Preferably, the branched components containing isocyanate groups have an average NCO functionality in the range of 2.2 to 4, especially 2.3 to 3.5.

[0057] Preferred diisocyanate oligomers are HDI biurets, such as Desmodur® N100 or N3200 (Covestro), Tolonate® HDB or HDB-LV (Vencorex) or Duranate® 24A-100 (Asahi Kasei Corporation); HDI isocyanurates, such as Desmodur® N3300, N3600 or N3790BA (all Covestro), Tolonate® HDT, HDT -LV or HDT-LV2 (Vencorex), Duranate® TPA-100 or THA-100 (Asahi Kasei Corporation) or Coronate® HX (Nippon Polyurethane Industry Co., Ltd.); HDI uretdiones, such as Desmodur® N3400 (Covestro); HDI iminooxadiazinediones, such as Desmodur® XP2410 (Covestro); HDI allophanates, such as Desmodur® VP LS2102 (Covestro); IPDI isocyanurates, such as Desmodur® Z4470 (Covestro) in the dissolved state or Vestanat® T1890 / 100 (Evonik) in the solid state; TDI oligomers, such as Desmodur® IL (Covestro); or mixed isocyanurates based on TDI / HDI, such as Desmodur® HL (Covestro) (wherein "HDI" means hexane 1,6-diisocyanate, "IPDI" means isophorone diisocyanate, and "TDI" means tolylene 2,4-diisocyanate or mixtures thereof with tolylene 2,6-diisocyanate).

[0058] Branched polymers containing isocyanate groups and having an average NCO functionality in the range of 2.2 to 3, especially 2.3 to 3, are preferred.

[0059] A particularly preferred branched polymer containing isocyanate groups has an NCO content in the range of 1% to 2.5% by weight and a diisocyanate monomer content of 0.3% by weight or less, and is obtainable by reacting 4,4'-MDI or IPDI, in particular 4,4'-MDI, with an optionally ethylene oxide-terminated polyoxypropylene triol having an average OH functionality in the range of 2.2 to 3 and an OH number in the range of 20 to 60 mg KOH / g, in particular 22 to 42 mg KOH / g, in an NCO / OH ratio of at least 4 / 1, and then removing most of the unconverted diisocyanate monomer.

[0060] Further particularly preferred branched polymers containing isocyanate groups are conventionally prepared polymers having an NCO content in the range of 1.2% to 2.5% by weight, obtained from the reaction of at least one diisocyanate monomer with at least one polyoxypropylene triol and optionally at least one polyoxypropylene diol, the triol and diol optionally containing a fraction of 1,2-ethyleneoxy groups, with an NCO / OH ratio in the range of 1.5 / 1 to 2.2 / 1. Preferred diisocyanate monomers for this purpose are 4,4'-MDI, TDI or IPDI.

[0061] The moisture-curable polyurethane composition contains, in addition to the polymer of the invention, at least one further linear polymer containing isocyanate groups. Particularly preferred for this purpose is a polymer having an NCO content of 1.6 to 2.4% by weight, in particular 1.6 to 2.1% by weight, and a diisocyanate monomer content of 0.3% by weight or less, which is obtained by reacting 4,4'-MDI with an optionally ethylene oxide-terminated polyoxypropylene triol having an OH number of 23 to 38 mg KOH / g, in particular 25 to 32 mg KOH / g, in an NCO / OH ratio of at least 4 / 1, and then removing most of the unconverted 4,4'-MDI.

[0062] Preferably, the moisture-curable polyurethane composition contains the linear polymer and the branched isocyanate group-containing component in a weight ratio ranging from 60 / 40 to 99 / 1, preferably from 70 / 30 to 98 / 2. Within this range, there is a particularly attractive combination of advantageous mechanical properties and good adhesion to plastic substrates.

[0063] When the moisture-curable polyurethane composition contains at least one diisocyanate oligomer, the weight ratio of the linear polymer to the diisocyanate oligomer is preferably in the range of 90 / 10 to 99.5 / 0.5, preferably 95 / 5 to 99 / 1, in particular 95 / 5 to 98 / 2.

[0064] When the moisture-curable polyurethane composition contains at least one branched polymer containing isocyanate groups, the weight ratio of the linear polymer to the branched polymer is preferably in the range of 60 / 40 to 95 / 5, in particular 70 / 30 to 90 / 10.

[0065] In one embodiment of the present invention, the moisture-curable polyurethane composition further comprises at least one blocked amine.

[0066] Suitable blocked amines preferably have at least one aldimino or oxazolidinino group, which upon contact with moisture can be hydrolyzed and react with available isocyanate groups, releasing the amino group and promoting rapid, blister-free curing, a particularly non-stick surface, and / or particularly good mechanical properties.

[0067] Preferred oxazolidines are oxazolidines derived from bisoxazolidine, isobutyraldehyde, benzaldehyde or substituted benzaldehydes, especially benzaldehydes substituted in the para position with an optionally branched alkyl group having 10 to 14 carbon atoms. Bisoxazolidines obtained by reacting OH-functional monooxazolidines with diisocyanates, especially hexamethylene 1,6-diisocyanate, are preferred. Suitable monooxazolidines are in particular obtained by reacting diethanolamine with aldehydes, with the release and removal of water.

[0068] Suitable aldimines are in particular the diamines or trialdimines obtained by reacting commercially available primary diamines or triamines with non-enolizable aldehydes, which are aldehydes that do not have a hydrogen atom in the alpha position relative to the carbon atom of the aldehyde group.

[0069] Particularly preferred blocked amines are N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)hexylene-1,6-diamine, N,N'-bis(2,2-dimethyl-3-acetoxypropylidene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine, N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine, N,N'-bis(benzylidene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine, N,N'-bis(4-C 10~14 -alkylbenzylidene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine, average molecular weight M in the range of 450-750 g / mol n N,N'-bis(2,2-dimethyl-3-acetoxypropylidene)polyoxypropylenediamine having an average molecular weight M in the range of 750 to 1,050 g / mol n N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)polyoxypropylenediamine having an average molecular weight M in the range of 380 to 680 g / mol nN,N'-bis(benzylidene)polyoxypropylenediamine having an average molecular weight M in the range of 680 to 1,100 g / mol n N,N'-bis(4-C 10~14 -alkylbenzylidene)polyoxypropylenediamine, average molecular weight M in the range of 730-880 g / mol n N,N',N''-tris(2,2-dimethyl-3-acetoxypropylidene)polyoxypropylenetriamine having an average molecular weight M in the range of 1,150 to 1,300 g / mol n N,N',N''-tris(2,2-dimethyl-3-lauroyloxypropylidene)polyoxypropylenetriamine having the formula:

[0070] The moisture-curable polyurethane composition preferably further comprises at least one additional component selected from a catalyst, a filler, a plasticizer, and a stabilizer.

[0071] Suitable catalysts are those that promote the reaction of isocyanate groups, especially organotin(IV) compounds, such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dibutyltin diacetylacetonate, dimethyltin dilaurate, dioctyltin diacetate, dioctyltin dilaurate, or dioctyltin diacetylacetonate, bismuth(III) or zirconium(IV) complexes with ligands selected from alkoxides, carboxylates, 1,3-diketonates, oxinates, 1,3-ketostearates, and 1,3-ketoamidates, or compounds containing tertiary amino groups, such as 2,2'-dimorpholinodiethyl ether (DMDEE). When the moisture-curable polyurethane composition contains blocked amines, suitable catalysts are also catalysts for the hydrolysis of blocked amino groups, especially organic acids, especially aromatic carboxylic acids such as benzoic acid, 2-nitrobenzoic acid, or salicylic acid. Also, combinations of different catalysts are particularly suitable.

[0072] Suitable fillers are, in particular, ground or precipitated calcium carbonate, optionally coated with a fatty acid, in particular stearic acid, baryta, quartz flour, quartz sand, dolomite, wollastonite, calcined kaolin, layered silicates such as mica or talc, zeolites, aluminum hydroxide, magnesium hydroxide, silica, including finely divided silica obtained from pyrolysis processes, cement, gypsum, fly ash, industrially produced carbon black, graphite, metal powders such as aluminum, copper, iron, silver or steel, PVC powder or hollow beads. Calcium carbonate, optionally coated with a fatty acid, in particular stearic acid, calcined kaolin or industrially produced carbon black are preferred.

[0073] Suitable plasticizers are in particular carboxylic acid esters, such as phthalates, in particular diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) or di(2-propylheptyl)phthalate (DPHP), hydrogenated phthalates or cyclohexane-1,2-dicarboxylic acid esters, in particular hydrogenated diisononyl phthalate or diisononyl cyclohexane-1,2-dicarboxylate (DINCH), terephthalates, in particular bis(2-ethylhexyl)terephthalate (DOTP) or diisononyl terephthalate (DINT), hydrogenated terephthalates or cyclohexane-1,4-dicarboxylic acid esters, in particular hydrogenated bis(2-ethylhexyl)terephthalate or bis(2-ethylhexyl)terephthalate (DINT). The preferred plasticizers are bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate, hydrogenated diisononyl terephthalate, diisononyl cyclohexane-1,4-dicarboxylate, isophthalate, trimellitate, adipate, especially dioctyl adipate, azelate, sebacate, benzoate, glycol ether, glycol ester, plasticizers with a polyether structure, especially polypropylene oxide mono-, di- or triols with blocked hydroxyl groups in the form of acetate groups, organic phosphoric or sulfonic acid esters, polybutene, polyisobutene, or plasticizers derived from natural fats or oils, especially epoxidized soybean or linseed oil. Preferred plasticizers are phthalate, hydrogenated phthalate, adipate, or polyether plasticizers.

[0074] Suitable stabilizers are in particular stabilizers against oxidation, heat, light or UV radiation. The composition preferably comprises at least one UV stabilizer.

[0075] The moisture-curable polyurethane composition may contain further additives, in particular - inorganic or organic pigments, in particular titanium dioxide, chromium oxide or iron oxide; fibres, in particular glass fibres, carbon fibres, metal fibres, ceramic fibres, polymer fibres such as polyamide fibres or polyethylene fibres or natural fibres such as wool, cellulose, hemp or sisal; - fillers such as graphene or carbon nanotubes; - dye; desiccants, in particular molecular sieve powders, calcium oxide, highly reactive isocyanates such as p-tosylisocyanate, monooxazolidines or orthoformates such as Incozol® 2 (Incorez); adhesion promoters, in particular organoalkoxysilanes, in particular epoxysilanes, such as in particular 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane, (meth)acrylosilanes, silane anhydrides, carbamatosilanes, alkylsilanes or iminosilanes or oligomeric forms of these silanes or titanates; - further catalysts that accelerate the reaction of isocyanate groups; rheology modifiers, in particular thickeners, in particular layered silicates, such as bentonite, derivatives of castor oil, hydrogenated castor oil, polyamides, polyamide waxes, polyurethanes, urea compounds, fumed silica, cellulose ethers or hydrophobically modified polyoxyethylene; solvents, in particular acetone, methyl acetate, tert-butyl acetate, 1-methoxy-2-propyl acetate, ethyl 3-ethoxypropionate, diisopropyl ether, diethylene glycol diethyl ether, ethylene glycol diethyl ether, ethylene glycol monobutyl ether, ethylene glycol mono-2-ethylhexyl ether, acetals such as propylal, butyral, 2-ethylhexylal, dioxolane, glycerol formal or 2,5,7,10-tetraoxaundecane (TOU), toluene, xylene, heptane, octane, naphtha, white spirit, petroleum ether or gasoline, in particular Solvesso™ grades (Exxon), and propylene carbonate, dimethyl carbonate, butyrolactone, N-methylpyrrolidone, N-ethylpyrrolidone, p-chlorobenzotrifluoride or benzotrifluoride; natural resins, fats or oils, such as rosin, shellac, linseed oil, castor oil or soybean oil; - non-reactive polymers, in particular homo- or copolymers of unsaturated monomers, in particular ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate or alkyl (meth)acrylates, in particular polymers from the group comprising polyethylene (PE), polypropylene (PP), polyisobutylene, ethylene / vinyl acetate copolymer (EVA) or atactic poly-α-olefins (APAO); - flame retardant substances, in particular the above-mentioned fillers aluminum hydroxide or magnesium hydroxide or organic phosphates; additives, in particular wetting agents, levelling agents, antifoaming agents, degassing agents or biocides; or Further materials commonly used in moisture-curable polyurethane compositions may contain

[0076] It may be advisable to chemically or physically dry certain materials before incorporating them into the composition.

[0077] When the polymers of the present invention containing isocyanate groups are mixed with further components of the composition, in particular fillers, the content of diisocyanate monomers can be further reduced by reacting with moisture present.

[0078] The moisture-curable polyurethane composition preferably comprises: - 30% to 70% by weight of a polymer containing isocyanate groups, of which 10% to 70% by weight is a polymer according to the invention, - 20% to 60% by weight of fillers, - 0% to 25% by weight, in particular 0% to 10% by weight, of a plasticizer, and Optionally, further components, in particular diisocyanate oligomers, blocked amines or catalysts Contains:

[0079] The moisture-curable polyurethane composition after curing has high strength combined with high elongation. The tensile strength, determined as described in the examples, is preferably at least 1.5 MPa, more preferably at least 2 MPa, and especially at least 2.5 MPa. The modulus, determined as described in the examples, in the range of 0.05 to 5% elongation, is preferably in the range of 2 to 20 MPa, especially 3 to 15 MPa. The elongation at break, determined as described in the examples, is preferably at least 300%, especially at least 500%.

[0080] The moisture-curable polyurethane composition is in particular prepared with the exclusion of moisture and stored at ambient temperature in a moisture-tight container. Suitable moisture-tight containers are in particular made of optionally coated metal and / or plastic, in particular drums, shipping boxes, shipping containers, buckets, canisters, cans, bags, tubular bags, cartridges or tubes.

[0081] The moisture-curable polyurethane composition may take the form of a one-component composition or a multi-component, especially a two-component, composition.

[0082] A composition referred to as a "one-component" composition is one in which all components of the composition are in the same container and are shelf stable as is.

[0083] Compositions referred to as "two-component" compositions are those in which the components of the composition are present in two different components stored in separate containers and are not mixed with each other until just before or at the time of application of the composition.

[0084] Moisture-curable polyurethane compositions are preferably one-component compositions, and when properly packaged and stored, are generally shelf stable for periods ranging from several months to over a year.

[0085] Once the moisture-curable polyurethane composition is applied, the curing process begins, resulting in a cured composition.

[0086] In the case of a one-component composition, it is applied as is and then begins to harden under the influence of moisture or water. To accelerate hardening, accelerator components containing or releasing water and / or catalysts and / or hardeners can be mixed into the composition at the time of application or can be contacted with the composition after its application.

[0087] During the curing process, isocyanate groups react with each other under the influence of moisture. If the moisture-curable polyurethane composition contains a blocked amine, the isocyanate groups, when hydrolyzed, further react with the blocked amino groups. The overall reaction of isocyanate groups, which results in curing of the composition, is also called crosslinking.

[0088] The moisture necessary for curing a moisture-curable polyurethane composition preferably enters the composition by diffusion from the air (atmospheric moisture). In the process, a solid layer of cured composition ("skin") forms on the surface of the composition that comes into contact with the air. Curing proceeds in a diffusional direction from the outside to the inside, and the skin gradually thickens until it eventually covers the entire applied composition. Moisture can also enter the composition further or entirely from one or more substrates to which the composition is applied, and / or can originate from accelerator components that are mixed into the composition during application or that come into contact with it after application, for example, by painting or spraying.

[0089] The moisture-curable polyurethane composition is preferably applied at ambient temperature, in the range of about −10 to 50° C., preferably −5 to 45° C., especially 0 to 40° C. The moisture-curable polyurethane composition is preferably cured at ambient temperature as well.

[0090] Moisture-curable polyurethane compositions have long processing times (open times) and rapid cure. When moisture-curable polyurethane compositions contain blocked amines, the aldehyde used to block the amino groups is released during the crosslinking process. If this is primarily nonvolatile, it remains in the cured composition to act as a plasticizer.

[0091] The moisture-curable polyurethane composition is preferably used as an elastic adhesive, or an elastic sealant, or an elastic coating.

[0092] The moisture-curing polyurethane compositions as adhesives and / or sealants are particularly suitable for joining and sealing applications in construction and manufacturing or in automotive assembly, in particular for parquet, joining assemblies, joining attachable parts, joining modules, joining glazings, sealing joints, sealing body structures, sealing seams or sealing cavities. Elastic joining in vehicle manufacturing is, for example, the adhesive attachment of parts such as plastic covers, trim strips, flanges, fenders, joining glazings into other parts or bodies attachable to the driver's cabin or the painted body of the vehicle, said vehicle being more particularly a car, truck, bus, train or ship.

[0093] Moisture-curing polyurethane compositions are particularly suitable as sealants for all kinds of joints, seams, or cavities, especially joints in construction, such as expansion joints or connecting joints made of structural components, especially plastics, floor joints in civil engineering, and elastic sealing. Flexible and highly flexible at low temperatures, these sealants are particularly suitable for sealing expansion joints in building structures. As coatings, moisture-curing polyurethane compositions are suitable for protecting and / or sealing architectural structures, especially in the field of plastic materials, especially balconies, terraces, roofs, especially flat or slightly sloped roof sections or roof gardens, or in damp rooms or building interiors under kitchen tiles or ceramic plates, drip pans, conduits, shafts, silos, tanks, or wastewater treatment systems. They can also be used for repair purposes, for example, as seals or coatings for leaking roof membranes or floor coverings that are no longer suitable for their purpose, or as repair compounds for highly reactive spray seals.

[0094] Moisture-curing polyurethane compositions can be formulated to have a paste-like consistency with structural viscosity. This type of composition is applied using a suitable device, such as a commercially available cartridge, barrel, or container, in the form of beads, which may have an essentially circular or triangular cross section. Moisture-curing polyurethane compositions are liquid and "self-leveling" or only slightly thixotropic, and can also be formulated so that they can be poured out for application. As a coating, it can then be evenly distributed to the desired layer thickness using, for example, a roller, a slide bar, a toothed applicator, or a trowel. In one operation, a layer thickness ranging from 0.5 to 3 mm, particularly from 1 to 2.5 mm, is typically applied.

[0095] It is preferred to use the moisture-curable polyurethane composition as a resilient adhesive, or a resilient sealant, or a resilient coating for bonding, sealing or coating at least one plastic substrate.

[0096] Suitable plastic substrates are in particular rigid and flexible PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM, EPDM or blends of polycarbonate with further plastics such as ABS and / or SAN, each of which may be in untreated form or in surface-treated form, for example treated with plasma, corona or flame, and may be fibre-reinforced plastics, such as in particular carbon fibre reinforced plastics (CFRP), glass fibre reinforced plastics (GFRP) or sheet moulding compounds (SMC).

[0097] Preferably, the plastic substrate is selected from the group consisting of rigid PVC, flexible PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM, EPDM, and blends of polycarbonate with further plastics, in particular ABS and / or SAN.

[0098] Among these, rigid PVC, polycarbonate, blends of polycarbonate with ABS and / or SAN, PMMA or ABS, especially polycarbonate or blends of polycarbonate, are preferred, as these plastics are particularly important for their good adhesion without complex pretreatment, especially when joining is frequently required.

[0099] Suitable further substrates which can be bonded or sealed or coated with the moisture-curable polyurethane composition are, in particular: - metals or alloys such as aluminium, copper, steel, non-ferrous metals, including surface-treated metals or alloys, for example zinc-plated or chrome-plated metals; - coated or painted substrates, in particular painted tiles, coated concrete, powder-coated metals or alloys or painted metal sheets; - paints or varnishes, especially automotive topcoats; - glass, glass ceramics, concrete, mortar, cement screed, fibre cement, in particular fibre cement board, brick, tile, gypsum, in particular gypsum board, or anhydrous screed, or natural stone such as granite or marble; - Repair or leveling compounds based on PCC (polymer-modified cement mortar) or ECC (epoxy resin-modified cement mortar); - Asphalt or bitumen; - Leather, textiles, paper, wood and wood materials bonded with resins such as phenolic, melamine or epoxy resins; further materials known as resin / textile composites or polymer composites; - Insulating foams, especially made of EPS, XPS, PUR, PIR, rock wool, glass wool or cellular glass is.

[0100] If necessary, the substrate can be pretreated before application, especially by physical and / or chemical cleaning methods or by application of an activator or primer.

[0101] It is possible to join and / or seal two of the same substrate or two different substrates.

[0102] The moisture-curable polyurethane composition is preferably used in a method of joining or sealing comprising the steps of: (i) combining a moisture-curable polyurethane composition described herein with - applying to a first substrate and contacting the composition with a second substrate within the open time of the composition; or applying a moisture-curable polyurethane composition described herein to a first and a second substrate and bonding the two substrates together within the open time of the composition; or - applying (spreading) a moisture-curable polyurethane composition described herein between two substrates; (ii) curing the composition upon contact with moisture;

[0103] The moisture-curable polyurethane composition is also preferably used in a coating or sealing method comprising the steps of: (i) applying (spraying) a moisture-curable polyurethane composition described herein to a substrate; (ii) curing the composition upon contact with moisture;

[0104] In these methods, preferably at least one of the substrates is a plastic substrate, as described above.

[0105] Application and curing of the moisture-curable polyurethane composition results in an article bonded or sealed or coated with the composition, which may be a building structure or part thereof, in particular a building structure in civil engineering above or below ground, a roof, a staircase or a facade, or an industrial or consumer product, in particular a window, a lamp, a traffic light, a household appliance or a means of transport, in particular a car, bus, caravan, truck, train, ship, aircraft or helicopter, or an attachable part thereof, such as a window, panoramic roof or lamp housing made of organic glass.

[0106] The present invention further provides a cured composition obtained from the moisture-curable polyurethane composition after contacting it with moisture.

[0107] The present invention further provides an adhesive bond comprising at least one plastic substrate and a composition cured by contact with moisture as described above. [Example]

[0108] Examples are presented below and are intended to further illustrate the described invention. The invention is, of course, not limited to these described examples.

[0109] "Standard Climatic Conditions ("SCC")" means a temperature of 23±1°C and a relative air humidity of 50±5%. Unless otherwise specified, chemicals used were obtained from Sigma-Aldrich.

[0110] Viscosity was measured with a thermostated Rheotec RC30 cone-plate viscometer (cone diameter 25 mm, cone angle 1°, cone tip-plate distance 0.05 mm, shear rate 10 s -1 The diisocyanate monomer content was determined by HPLC (detection via photodiode array; 0.04 M sodium acetate / acetonitrile as mobile phase) before and after derivatization with n-propyl-4-nitrobenzylamine.

[0111] Polyols used: Acclaim® 4200: Polyoxypropylene diol, OH value 28 mg KOH / g (Covestro) Acclaim® 8200N: Polyoxypropylene diol, OH value 14 mg KOH / g (Covestro) Acclaim® 12200N: Polyoxypropylene diol, OH value 10 mg KOH / g (Covestro) Desmophen® 5031BT: Ethylene oxide terminated polyoxypropylene triol, OH value 28 mg KOH / g (Covestro).

[0112] Diisocyanate monomers used: Desmodur® 44MC L: diphenylmethane 4,4′-diisocyanate (Covestro) with an NCO content of 33.6% by weight.

[0113] Preparation of polymers containing isocyanate groups: Polymer L1 (linear): The reaction of 757.7 g of Acclaim® 8200N (0.19 equivalents of OH) and 242.3 g of Desmodur® 44MC L (1.9 equivalents of NCO) at 80°C by known methods yielded a polymer with an NCO content of 7.2 wt%, a viscosity of 6.8 Pa·s at 20°C, and a diphenylmethane 4,4′-diisocyanate monomer content of approximately 20 wt%. Subsequently, most of the volatile components, especially the diphenylmethane 4,4′-diisocyanate monomer, were removed by distillation in a short-path evaporator (jacket temperature 180°C, pressure 0.1-0.005 mbar, condensation temperature 47°C). The linear polymer thus obtained had an NCO content of 1.0 wt%, a viscosity of 25.0 Pa·s at 20°C, and a diphenylmethane 4,4′-diisocyanate monomer content of 0.06 wt%.

[0114] Polymer L2 (linear): The reaction of 812.0 g of Acclaim® 12200N (0.15 equivalents of OH) and 188.0 g of Desmodur® 44MC L (1.5 equivalents of NCO) at 80°C by known methods yielded a polymer with an NCO content of 5.6 wt%, a viscosity of 13.9 Pa·s at 20°C, and a diphenylmethane 4,4′-diisocyanate monomer content of approximately 14 wt%. Subsequently, most of the volatile components, especially the diphenylmethane 4,4′-diisocyanate monomer, were removed by distillation in a short-path evaporator (jacket temperature 180°C, pressure 0.1-0.005 mbar, condensation temperature 47°C). The linear polymer thus obtained had an NCO content of 0.7 wt%, a viscosity of 29.4 Pa·s at 20°C, and a diphenylmethane 4,4′-diisocyanate monomer content of 0.04 wt%.

[0115] Polymer Reference-1 (linear, for comparison): 727.0 g of Acclaim® 4200 and 273.0 g of Desmodur® 44MC L were reacted at 80°C by known methods to yield a polymer with an NCO content of 7.4 wt%, a viscosity of 5.2 Pa·s at 20°C, and a content of approximately 17 wt% diphenylmethane 4,4′-diisocyanate monomer. Subsequently, most of the volatile components, especially the diphenylmethane 4,4′-diisocyanate monomer, were removed by distillation in a short-path evaporator (jacket temperature 180°C, pressure 0.1-0.005 mbar, condensation temperature 47°C). The linear polymer thus obtained had an NCO content of 1.8 wt%, a viscosity of 13.3 a·s at 20°C, and a content of 0.08 wt% diphenylmethane 4,4′-diisocyanate monomer.

[0116] Polymer C1 (branched): The reaction of 725.0 g of Desmophen® 5031BT and 275 g of Desmodur® 44MC L at 80°C by known methods yielded a polymer with an NCO content of 7.6 wt%, a viscosity of 6.5 Pa·s at 20°C, and a diphenylmethane 4,4′-diisocyanate monomer content of approximately 20 wt%. Subsequently, most of the volatile components, especially the diphenylmethane 4,4′-diisocyanate monomer, were removed by distillation in a short-path evaporator (jacket temperature 180°C, pressure 0.1-0.005 mbar, condensation temperature 47°C). The polymer thus obtained had an NCO content of 1.7 wt%, a viscosity of 19 Pa·s at 20°C, and a diphenylmethane 4,4′-diisocyanate monomer content of 0.04 wt%.

[0117] Moisture-curable polyurethane compositions: Compositions Z1~Z7: For each compound, the components specified in Table 1 were mixed in the specified amounts (parts by weight) using a centrifugal mixer (SpeedMixer™ DAC 150, FlackTek Inc.) at 3000 rpm for 1 minute, with the moisture removed, and the mixture was stored. Each composition was tested as follows:

[0118] The Shore A hardness was determined on test specimens cured for 14 days under standard climatic conditions in accordance with DIN 53505. To determine the mechanical properties, the compositions were applied to a silicone-coated release paper to obtain a 2 mm thick film, which was stored under standard climatic conditions for 14 days, and several dumbbells having a length of 75 mm with a bar length of 30 mm and a bar width of 4 mm were punched out of the film and these were tested for tensile strength (breaking force), elongation at break and 5% modulus (at elongation of 0.5 to 5%) according to DIN EN 53504 at a strain rate of 200 mm / min.

[0119] Adhesion to plastic substrates was determined by applying four parallel beads of the composition, each approximately 10 mm wide, 5 mm high, and 15 mm long, to each substrate and allowing them to cure for 7 days under standard climatic conditions. The cured composition's adhesion was then first tested by slitting the first bead at its narrow end directly above the joining surface, holding the cut end of the bead with round tweezers, and attempting to pull the bead away from the substrate. The bead was then re-slit downwards against the substrate, the detached portion was retracted with the round tweezers, and another attempt was made to detach the bead from the substrate. In this manner, the entire bead was cut off by pulling it away from the substrate. Adhesion was then evaluated from the failure profile, which is reported in Table 1 under "7-Day SCC." A portion of the specimen was then immersed in deionized water for 7 days, then stored under standard climatic conditions for 2 hours, and then a second bead was detached from the substrate by pulling it with round tweezers. Adhesion was evaluated from the failure profile, which is reported in Table 1 under "7-Day H2O." The specimens were then stored in an air-circulating oven at 80°C for 24 hours, followed by two hours under standard climate conditions, and then a third bead was tested for adhesion as described and adhesion was assessed from the failure profile reported in Table 1 under "1 day at 80°C". Finally, the specimens were stored at 70°C and 100% relative humidity for 7 days, followed by two hours under standard climate conditions, and a fourth bead was tested for adhesion as described and adhesion was assessed from the failure profile reported in Table 1 under "7 days at 70°C / 100% relative humidity".

[0120] The plastic substrates used were the following plastic sheets (300 x 200 x 2 mm): PMMA: Plexiglas® XT 0A000 (Evonik Röhm) PC: Makrolon® GP clear099 (uncoated polycarbonate, Covestro) ABS:Metzoplast ABS / G(Metzeler Plastics GmbH) PVC: KoemaDur® ES (Koemmerling Kunststoffe) Adhesion was rated under the following scale: 100 represents greater than 95% cohesive failure, meaning very good adhesion. 40 represents 40% cohesive failure, meaning moderate adhesion. 5 represents 5% cohesive failure, meaning poor adhesion. 0 represents 0% cohesive failure (100% adhesive failure), meaning poor adhesion.

[0121] The results are reported in Table 1. Comparative examples are identified by (reference).

[0122] [Table 1] The present disclosure includes the following inventive aspects: <Aspect 1> A linear polymer containing an isocyanate group and having an NCO content in the range of 0.3% by weight to 1.5% by weight and a diisocyanate monomer content of 0.5% by weight or less, 1. A process for producing a polyether diol having an OH value ranging from 5 to 21 mg KOH / g, comprising reacting at least one aromatic diisocyanate monomer with a polyether diol having an NCO / OH ratio of at least 5 / 1, and then removing most of the aromatic diisocyanate monomer by a suitable separation method. Linear polymer. <Aspect 2> 2. The polymer of claim 1, wherein the aromatic diisocyanate monomer is diphenylmethane 4,4'-diisocyanate. <Aspect 3> 3. The polymer of claim 1 or 2, wherein the polyether diol contains 80% to 100% by weight of 1,2-propyleneoxy groups and 0% to 20% by weight of 1,2-ethyleneoxy groups. <Aspect 4> 4. The polymer of any one of aspects 1 to 3, wherein the polyether diol has an OH number in the range of 6 to 19 mg KOH / g and an average OH functionality of at least 1.9. <Aspect 5> Aspect 5. The polymer of any one of aspects 1 to 4, wherein excess diisocyanate monomer is removed by distillation. <Aspect 6> 6. The polymer of any one of aspects 1 to 5, having an NCO content in the range of 0.5 wt.% to 1.3 wt.% and a diisocyanate monomer content of 0.3 wt.% or less. <Aspect 7> 7. The polymer of any one of the preceding aspects, wherein the NCO content is at least 90% of the theoretical NCO content calculated from the addition of one mole of diisocyanate monomer per mole of OH groups of the polyether diol. <Aspect 8> A moisture-curable polyurethane composition having a diisocyanate monomer content of less than 0.1 wt.%, comprising the polymer of any one of embodiments 1-7. <Aspect 9> A moisture-curable polyurethane composition according to Aspect 8, having a content of the polymer according to any one of Aspects 1 to 7 in the range of 5% by weight to 80% by weight, based on the total composition. <Aspect 10> 10. The moisture-curable polyurethane composition of claim 8 or 9, having a content of the polymer of any one of claims 1 to 7 in an amount of at least 25 wt.%, based on the total amount of polymers containing isocyanate groups in the composition. <Aspect 11> 11. The moisture-curable polyurethane composition of any one of aspects 8 to 10, further comprising at least one component containing an isocyanate group and having an average NCO functionality greater than 2. <Aspect 12> 12. Use of the moisture-curable polyurethane composition according to any one of aspects 8 to 11 as an elastic adhesive, or elastic sealant, or elastic coating for bonding, sealing, or coating at least one plastic substrate. <Aspect 13> 13. Use according to aspect 12, characterized in that the plastic substrate is selected from the group consisting of rigid PVC, flexible PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM, EPDM, and blends of polycarbonate with further plastics, in particular ABS and / or SAN. <Aspect 14> A cured composition obtained after contacting the moisture-curable polyurethane composition according to any one of embodiments 8 to 11 with moisture. <Aspect 15> A bonded composite comprising at least one plastic substrate and the polyurethane composition of any one of embodiments 8-11 cured by contact with moisture.

Claims

1. A linear polymer containing isocyanate groups and having an NCO content in the range of 0.5% to 1.3% by weight and a diisocyanate monomer content of 0.5% by weight or less, A linear polymer characterized in that it is obtained by reacting at least one aromatic diisocyanate monomer with a polyether diol having an OH number in the range of 9 to 14 mg KOH / g in an NCO / OH ratio of at least 5 / 1.

2. 2. The polymer of claim 1, wherein the aromatic diisocyanate monomer is diphenylmethane 4,4'-diisocyanate.

3. 3. The polymer according to claim 1, wherein the polyether diol contains from 80% to 100% by weight of 1,2-propyleneoxy groups and from 0% to 20% by weight of 1,2-ethyleneoxy groups.

4. 4. Polymer according to any one of claims 1 to 3, characterized in that the polyether diol has an average OH functionality of at least 1.

9.

5. 5. The polymer according to claim 1, having a diisocyanate monomer content of not more than 0.3% by weight.

6. 6. The polymer according to claim 1, wherein the NCO content is at least 90% of the theoretical NCO content calculated from the addition of one mole of diisocyanate monomer per mole of OH group of the polyether diol.

7. A moisture-curable polyurethane composition having a diisocyanate monomer content of less than 0.1 wt.%, said moisture-curable polyurethane composition comprising a polymer according to any one of claims 1 to 6.

8. 8. A moisture-curable polyurethane composition according to claim 7, characterized in that it has a content of the polymer according to any one of claims 1 to 6 in the range of 5% by weight to 80% by weight, based on the total composition.

9. 9. A moisture-curable polyurethane composition according to claim 7 or 8, characterized in that it has a content of the polymer according to any one of claims 1 to 6 of at least 25% by weight, based on the total amount of polymers containing isocyanate groups in the composition.

10. 10. The moisture-curable polyurethane composition of any one of claims 7 to 9, further comprising at least one component containing isocyanate groups and having an average NCO functionality greater than 2.

11. Use of the moisture-curable polyurethane composition according to any one of claims 7 to 10 as an elastic adhesive, or elastic sealant, or elastic coating for bonding, sealing, or coating at least one plastic substrate.

12. 12. Use according to claim 11, characterized in that the plastic substrate is selected from the group consisting of rigid PVC, flexible PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM, EPDM, and blends of polycarbonate with ABS and / or SAN.

13. A cured composition obtained after contacting the moisture-curable polyurethane composition according to any one of claims 7 to 10 with moisture.

14. A bonded composite comprising at least one plastic substrate and the polyurethane composition of any one of claims 7 to 10 cured by contact with moisture.

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