Linear polymers containing isocyanate groups

Abstract

The invention relates to a linear polymer containing isocyanate groups, the polymer having an NCO content of 0.3 to 1.5% by weight and a monomeric diisocyanate content of up to 0.5% by weight, characterised in that the polymer is obtained by reacting at least one monomeric aromatic diisocyanate and a polyether diol in an NCO / OH ratio of at least 5 / 1, followed by removal of the majority of the monomeric aromatic diisocyanate by a suitable separation process, the polyether diol having an OH-number of 5 to 21 mg KOH / g, and a moisture-curing polyurethane composition comprising the polymer and having a monomeric diisocyanate content of less than 0.1% by weight. The polymer according to the invention enables elastic adhesives with high ductility, unexpectedly high strength and unexpectedly good adhesion to plastic substrates to be achieved.

Description

Technical Field

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

[0002] Polyurethane compositions which crosslink by reaction of isocyanate groups with moisture or water and cure to form elastomers are used, in particular, as elastic adhesives or sealants in the construction and manufacturing industries, for example for bonding components during assembly or for filling joints. Due to their good adhesion and elasticity, they can gently dampen and dissipate forces acting on the substrate, for example due to vibrations or temperature changes.

[0003] This polyurethane composition comprises a polymer containing isocyanate groups as a binder, which is prepared by the reaction of a polyol with a monomeric diisocyanate. The polymer thus obtained contains a residual content of monomeric diisocyanates due to the chain extension reaction, usually 1 to 3% by weight. Monomeric diisocyanates may be harmful to health. Formulations containing monomeric diisocyanates (especially when the concentration exceeds 0.1% by weight) must be provided with hazard symbols and warning information on the label and in the data sheet, and can only be sold and used under specific circumstances in some countries. Therefore, people are interested in polyurethane compositions with low monomer content (especially less than 0.1% by weight). An attractive approach to obtain isocyanate-containing polymers with low monomeric diisocyanate content is to use an excess of monomeric diisocyanates in the preparation of the polymer, and then remove most of the unconverted monomeric diisocyanates by distillation. The approach is particularly easy to carry out using low molecular weight and therefore volatile monomeric diisocyanates (e.g. hexane diisocyanate).

[0004] However, polymers based on this lead to products that cure slowly and have low mechanical strength.

[0005] Polymers based on 4,4'-diphenylmethane diisocyanate (4,4'-MDI) achieve high strength and elasticity. However, production is more complicated due to the lower volatility of 4,4'-MDI, where excess monomer is removed by distillation.

[0006] Elastic adhesives for bonding plastic substrates are in increasing demand in industry, for example for bonding headlight housings or panoramic roofs in vehicles, plexiglass for ships or trains or various parts for trailers. The adhesives here should cure quickly and reliably, be very elastic while having high strength, and have high adhesion even under thermal and water loads without complicated pretreatment of the plastic substrates. However, adhesives based on polymers with a low monomer content also show weaknesses in establishing adhesion to plastic substrates, especially due to the large lack of monomeric diisocyanates. Summary of the invention

[0007] It was therefore an object of the present invention to provide a polymer with a low monomeric diisocyanate content which enables non-marking elastic adhesives with reliable curing and high strength and which have significantly improved adhesion to plastic substrates.

[0008] The object is achieved by a linear polymer according to claim 1. The polymer has an NCO content of 0.3 to 1.5% by weight and is based on an aromatic monomeric diisocyanate (in particular 4,4'-diphenylmethane diisocyanate) and a polyether diol with an OH value of 5 to 21 mg KOH / g. The polymer according to the invention is linear and has a relatively long chain length and a low monomeric diisocyanate content. The polymer is liquid at room temperature, has a relatively low viscosity and has an excellent storage stability when moisture is excluded. The polymer enables elastic adhesives with an attractive EHS classification and surprisingly good adhesion to plastic substrates (such as PVC, PMMA or polycarbonate) even under thermal and water loads. It is also particularly surprising that the polymer according to the invention imparts excellent mechanical properties to the adhesive, in particular high strength (tensile strength and elastic modulus), which is unexpected for such long-chain linear polymers. Compared to polymers based on short-chain polyether diols, the polymer according to the invention has comparable mechanical properties while achieving significantly better adhesion to plastic substrates.

[0009] 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

[0010] The invention relates to linear polymers containing isocyanate groups having an NCO content of 0.3 to 1.5% by weight and a monomeric diisocyanate content of up to 0.5% by weight, characterized in that the polymers are obtained by reacting at least one monomeric aromatic diisocyanate and a polyether diol in an NCO / OH ratio of at least 5 / 1 and then removing the majority of the monomeric aromatic diisocyanate by suitable separation methods, the polyether diol having an OH number of 5 to 21 mg KOH / g.

[0011] "Monomeric diisocyanate" means an organic compound having two isocyanate groups separated by a divalent hydrocarbon radical having from 4 to 15 carbon atoms.

[0012] An "aromatic" isocyanate group refers to an isocyanate group that is directly bonded to an aromatic carbon atom. Accordingly, isocyanates having only aromatic isocyanate groups are referred to as "aromatic isocyanates". An "aliphatic" isocyanate group refers to an isocyanate group that is directly bonded to an aliphatic or alicyclic carbon atom. Accordingly, isocyanates having only aliphatic isocyanate groups are referred to as "aliphatic isocyanates".

[0013] "Monomeric aromatic diisocyanate" means a monomeric diisocyanate having an aromatic isocyanate group.

[0014] "NCO content" means the content of isocyanate groups in weight %. "Molecular weight" means the molar mass of a molecule or a molecular group in g / mol. "Average molecular weight" means the number average molecular weight (M) of a polydisperse mixture of oligomeric or polymeric molecules or molecular groups. n ). The average molecular weight is determined by gel permeation chromatography (GPC) relative to polystyrene standards. "Storage-stable" or "storable" means that the substance or composition can be stored in a suitable container at room temperature for a long time, usually at least 3 months, preferably up to 6 months and longer, without its application properties or use properties changing during storage to a degree relevant to its use.

[0015] “Plastic” refers to organic materials based on macromolecules, which are also called “plastics”.

[0016] "Room temperature" means a temperature of 23°C.

[0017] All industry standards or specifications mentioned herein refer to the versions in effect at the time of initial filing.

[0018] Unless otherwise indicated, weight percent (abbreviated as wt%) represents the mass proportion of a component in a composition or molecule based on the entire composition or based on the entire molecule. The terms "mass" and "weight" are used synonymously herein.

[0019] The isocyanate group-containing polymers according to the invention may also be referred to as prepolymers.

[0020] Preferably, the polymers according to the invention have an NCO content of 0.5 to 1.3% by weight, in particular 0.7 to 1.1% by weight.

[0021] Particularly preferably, the polymer has an NCO content of 0.8 to 1.1% by weight, in particular 0.9 to 1.1% by weight. Such polymers enable compositions which have very good adhesion to plastic substrates and are particularly storage-stable.

[0022] The polymers according to the invention preferably have a monomeric diisocyanate content of up to 0.3% by weight, in particular up to 0.2% by weight. Such polymers are particularly suitable for preparing moisture-curing polyurethane compositions having a monomeric diisocyanate content of less than 0.1% by weight; these moisture-curing polyurethane compositions can be handled safely even without special protective measures and can therefore be sold without hazard identification in many countries.

[0023] Suitable monomeric aromatic diisocyanates are in particular 4,4′-diphenylmethane diisocyanate, optionally with a proportion of 2,4′- and / or 2,2′-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate or a mixture thereof with 2,6-toluene diisocyanate (TDI), 1,4-phenylene diisocyanate (PDI), 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene-1,5-diisocyanate (NDI) or 3,3′-dimethyl-4,4′-diisocyanatobiphenyl (TODI).

[0024] Among them, 4,4′-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, or 1,4-phenylene diisocyanate is preferred.

[0025] Particularly preferred as monomeric aromatic diisocyanate is 4,4'-diphenylmethane diisocyanate (4,4'-MDI). 4,4'-MDI is of a quality that contains only small amounts of 2,4'- and / or 2,2'-diphenylmethane diisocyanate and is solid at room temperature. It enables adhesives with particularly rapid curing and particularly high strength as well as high ductility and elasticity. 4,4'-MDI is preferably distilled and has a purity of at least 95%, in particular at least 97.5%.

[0026] Commercially available 4,4'-diphenylmethane diisocyanates of this quality are, for example 44MC (from Covestro) or MRS or ME (from BASF) or 1400 (from Huntsman).

[0027] The polyether diols preferably comprise repeating units selected from the group consisting of 1,2-ethylene oxide, 1,2-propylene oxide, 1,3-propylene oxide, 1,2-butylene oxide and 1,4-butylene oxide. Preference is given to 1,2-propylene oxide groups, optionally with a proportion of 1,2-ethylene oxide groups.

[0028] In particular, the polyether diols contain 80 to 100% by weight of 1,2-propylene oxide groups and 0 to 20% by weight of 1,2-ethylene oxide groups.

[0029] If the polyetherdiol comprises 1,2-ethylene oxide groups, the 1,2-propylene oxide groups and the 1,2-ethylene oxide groups preferably each form a homogeneous block, and the poly(1,2-ethylene oxide) blocks are located at the chain ends.

[0030] The polyetherdiols preferably have an OH number of 6 to 19 mg KOH / g, in particular 9 to 14 mg KOH / g, most preferably 12 to 14 mg KOH / g.

[0031] The average molecular weight of polyether diol is M n It is preferably 5500 to 20000 g / mol, particularly preferably 6000 to 18000 g / mol, in particular 8000 to 12000 g / mol, most preferably 8000 to 9000 g / mol.

[0032] The polyether diols preferably have an average OH functionality of at least 1.8, in particular at least 1.9. Commercially available polyether diols contain a certain content of monohydric alcohols as a result of the preparation, so that their average OH functionality is usually slightly below 2.

[0033] The polyether diols preferably have an unsaturation 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 of less than 0.01 mEq / g are prepared in particular with the aid of so-called double metal cyanide complex catalysts (DMC catalysts).

[0034] The polyetherdiols particularly preferably have an OH number of 6 to 19 mg KOH / g, in particular 9 to 14 mg KOH / g, most preferably 12 to 14 mg KOH / g, and an average OH functionality of at least 1.9.

[0035] Suitable polyether diols are commercially available, for example Polyol 8200 N, Polyol 12200 N, Polyol 18200 N (both from Covestro) or S 4013F (from Asahi Glass).

[0036] Preferably, the polymers according to the invention have an average molecular weight M of 6000 to 40000 g / mol. n , the average molecular weight M nDetermined by gel permeation chromatography (GPC) relative to polystyrene standards using tetrahydrofuran as mobile phase and a refractive index detector.

[0037] Particularly preferably, the average molecular weight M n 8,000 to 30,000 g / mol, in particular 8,000 to 15,000 g / mol.

[0038] The polymers according to the invention are obtained by reacting at least one monomeric aromatic diisocyanate with a polyether diol in an NCO / OH ratio of at least 5 / 1.

[0039] The NCO / OH ratio is preferably 5 / 1 to 20 / 1, particularly preferably 6 / 1 to 15 / 1, in particular 7 / 1 to 13 / 1. The reaction is preferably carried out at a temperature in the range of 20 to 160° C., in particular 40 to 140° C., optionally in the presence of a suitable catalyst, with exclusion of moisture.

[0040] After the reaction, the monomeric diisocyanate remaining in the reaction mixture is removed by suitable separation methods until the stated residual content is reached.

[0041] Preferred separation methods are distillation methods, in particular thin-film distillation or short-path distillation, preferably with the application of a vacuum.

[0042] Particular preference is given to a multistage process in which the monomeric aromatic diisocyanate is removed in a short-path evaporator at a jacket temperature of from 120 to 200° C. and a pressure of from 0.001 to 0.5 mbar.

[0043] In the case of 4,4'-MDI, which is preferred as the monomeric aromatic diisocyanate, the requirements for distillative removal are particularly stringent. For example, care must be taken that the condensate does not solidify and clog the apparatus. Preference is given to operating at jacket temperatures of 160 to 200° C. and 0.001 to 0.5 mbar, and the removed monomers are condensed at temperatures of 40 to 60° C.

[0044] Preferably, the reaction of the monomeric aromatic diisocyanate with the polyether diol and the subsequent removal of the majority of the monomeric diisocyanate remaining in the reaction mixture are carried out without the use of solvents or entrainers.

[0045] Preferably, the aromatic monomeric diisocyanate removed after the reaction is subsequently reused, ie, used again for preparing the isocyanate group-containing polymer.

[0046] Very particularly preferably, the isocyanate group-containing polymer has an NCO content of 0.5 to 1.3% by weight and a monomeric diisocyanate content of up to 0.3% by weight. Such polymers are particularly suitable for elastic adhesives having good adhesion to plastic substrates, good mechanical properties and a good EHS classification.

[0047] The polymer according to the invention is liquid at room temperature and has a relatively low viscosity. Its viscosity at 20° C. is preferably at most 80 Pa·s, in particular at most 70 Pa·s, particularly preferably at most 60 Pa·s. The viscosity here is measured using a cone and plate viscometer at 10 s -1 Determined at a shear rate of .

[0048] In this reaction, the OH groups of the polyether diol react with the isocyanate groups of the monomeric aromatic diisocyanate. This also leads to so-called chain extension reactions, in which the OH groups and / or isocyanate groups of the reaction product between the diol and the monomeric diisocyanate react. The higher the selected NCO / OH ratio, the fewer chain extension reactions occur and the lower the polydispersity and the viscosity of the resulting polymer. A measure of the chain extension reaction is the average molecular weight of the polymer or the width and distribution of the peaks in the GPC analysis. Another measure is the effective NCO content of the monomer-free polymer relative to the theoretical NCO content calculated from the reaction of each OH group with the monomeric aromatic diisocyanate.

[0049] The polymers according to the invention preferably contain only low contents of chain-extending components. The NCO content in the polymers according to the invention is preferably at least 90%, in particular at least 95%, of the theoretical NCO content, calculated by adding one mole of monomeric diisocyanate per mole of OH groups of the polyether diol.

[0050] The polymers according to the invention have low viscosity, contain a low content of monomeric diisocyanates and are very storage-stable with exclusion of moisture. They are particularly suitable for preparing elastic adhesives which cure quickly, have high strength, high extensibility and adhere particularly well to plastic substrates.

[0051] A further subject matter of the present invention is a moisture-curing polyurethane composition having a monomeric diisocyanate content of less than 0.1% by weight, which comprises the linear polymers according to the invention containing isocyanate groups.

[0052] The moisture-curing polyurethane composition preferably has a content of 5 to 80% by weight, in particular 10 to 70% by weight, particularly preferably 20 to 60% by weight, of the polymer according to the invention, based on the entire composition.

[0053] In addition to the polymer according to the invention, the moisture-curing polyurethane composition may also contain at least one further isocyanate group-containing polymer which does not correspond to the polymer according to the invention. Suitable further isocyanate group-containing polymers are conventionally prepared polymers or other monomer-free polymers. Other aromatic isocyanate group-containing polymers are suitable, as are aliphatic isocyanate group-containing polymers.

[0054] Suitable further isocyanate group-containing polymers are obtained by reacting at least one polyol with a superstoichiometric amount of at least one diisocyanate, preferably at a temperature in the range of 20 to 160° C., in particular 40 to 140° C., optionally in the presence of a suitable catalyst, with exclusion of moisture.

[0055] The NCO / OH ratio is preferably in the range from 1.3 / 1 to 10 / 1. The monomeric diisocyanates remaining in the reaction mixture after the reaction of the OH groups can be removed, in particular by distillation.

[0056] If monomeric diisocyanates are removed from the polymer, the NCO / OH ratio in the reaction is preferably in the range from 3 / 1 to 10 / 1, and the isocyanate-group-containing polymer obtained preferably comprises, after distillation, up to 0.5% by weight, particularly preferably up to 0.3% by weight, of monomeric diisocyanates.

[0057] If monomeric diisocyanates are not removed from the polymer, the NCO / OH ratio in the reaction is preferably in the range from 1.3 / 1 to 2.5 / 1. Such polymers contain in particular up to 3.5% by weight, preferably up to 2% by weight, of monomeric diisocyanates.

[0058] Preferred monomeric diisocyanates are the aromatic diisocyanates already mentioned, and also aliphatic or cycloaliphatic diisocyanates, in particular MDI, TDI, 1,6-hexane diisocyanate (HDI), isophorone diisocyanate (IPDI) or perhydro-2,4′- or -4,4′-diphenylmethane diisocyanate (HMDI), or mixtures thereof.

[0059] Particular preference is given to 4,4'-MDI, TDI or IPDI.

[0060] Suitable polyols are commercially available polyols or mixtures thereof, in particular:

[0061] - polyether polyols, in particular polyoxyalkylene diols and / or polyoxyalkylene triols, in particular the polymerization products of ethylene oxide or 1,2-propylene oxide or 1,2- or 2,3-butylene oxide or oxetane or tetrahydrofuran or mixtures thereof, which can be polymerized with the aid of starter molecules having two or three active hydrogen atoms, in particular water, ammonia or compounds having a plurality of OH groups or NH groups, for example 1,2 -ethylene glycol, 1,2- or 1,3-propylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, isomeric dipropylene glycol or tripropylene glycol, isomeric butanediols, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, 1,3- or 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol or aniline, or mixtures of the aforementioned compounds. Also suitable are polyether polyols having polymer particles dispersed therein, in particular those having styrene-acrylonitrile particles (SAN) or polyurea particles or polyhydrazonodicarboxamide particles (PHD).

[0062] Preferred polyether polyols are polyoxypropylene diols or triols, or so-called ethylene oxide-terminated (EO-terminated or EO-terminated) polyoxypropylene diols or triols. The latter are obtained, in particular, by further alkoxylation of polyoxypropylene diols or triols with ethylene oxide after the polypropoxylation reaction has been completed and thus have primary hydroxyl groups.

[0063] Preferred polyether polyols have an unsaturation of less than 0.02 mEq / g, in particular less than 0.01 mEq / g.

[0064] - Polyester polyols (also called oligoesterols), obtainable by known processes, in particular polycondensation of hydroxycarboxylic acids or lactones or of aliphatic and / or aromatic polycarboxylic acids with diols or polyols. Preference is given to polyester diols obtained from the reaction of diols, such as, in particular, 1,2-ethanediol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 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, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid or 1,4-cyclohexanedicarboxylic acid or mixtures of the above acids, or polyester polyols formed from lactones, such as, in particular, ε-caprolactone. Particular preference is given to polyester polyols obtained from adipic acid or sebacic acid or dodecanedicarboxylic acid and hexanediol or neopentyl glycol.

[0065] Polycarbonate polyols, for example those obtainable by reaction of the alcohols such as those mentioned above (used for the synthesis of the polyester polyols) with dialkyl carbonates, diaryl carbonates or phosgene.

[0066] - Block copolymers carrying at least two hydroxyl groups, which have at least two different blocks having a polyether, polyester and / or polycarbonate structure of the abovementioned type, in particular polyether polyester polyols.

[0067] - Polyacrylate polyol or polymethacrylate polyol.

[0068] - polyhydroxy-functional fats or oils, for example natural fats and oils, in particular castor oil; or polyols obtained by chemical modification of natural fats and oils (so-called oleochemical) such as epoxy polyesters or epoxy polyethers obtained by epoxidation of unsaturated oils and subsequent 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 decomposition processes (for example alcoholysis or ozonolysis) and subsequent chemical bonding of the decomposition products obtained or derivatives thereof (for example by transesterification or dimerization). Suitable decomposition 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 to hydroxy fatty acid esters, for example by hydroformylation and hydrogenation.

[0069] - Polyolefin polyols, also known as oligomeric hydrocarbon alcohols, such as, in particular, polyhydroxy-functional polyolefins, polyisobutylenes, polyisoprenes; polyhydroxy-functional ethylene-propylene copolymers, ethylene-butylene copolymers or ethylene-propylene-diene copolymers, such as those prepared by Kraton Polymers; polyhydroxy-functional polymers of dienes, in particular 1,3-butadiene, which can in particular also be prepared by anionic polymerization; polyhydroxy-functional copolymers of dienes, for example 1,3-butadiene or diene mixtures, and vinyl monomers, for example styrene, acrylonitrile, vinyl chloride, vinyl acetate, vinyl alcohol, isobutylene or isoprene, in particular polyhydroxy-functional acrylonitrile / butadiene copolymers, for example, acrylonitrile / butadiene copolymers terminated in particular by epoxides or amino alcohols and carboxyl groups (for example, those known under the name CTBN or CTBNX or ETBN commercially available from Emerald Performance Materials); or a hydrogenated polyhydroxy-functional diene polymer or copolymer.

[0070] Also particularly suitable are mixtures of the polyols mentioned.

[0071] Preference is given to polyols and / or polyether triols having an OH value of at least 22 mg KOH / g.

[0072] In the preparation of the isocyanate group-containing polymers, it is also possible to additionally use certain amounts of difunctional or polyfunctional alcohols, in particular 1,2-ethanediol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,3-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, dibromoneopentyl glycol, 1,2-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,2-octanediol, 1,8-Octanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,3- or 1,4-cyclohexanedimethanol, ethoxylated bisphenol A, propoxylated bisphenol A, cyclohexanediol, hydrogenated bisphenol A, dimerized fatty acid alcohols, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, pentaerythritol, sugar alcohols such as, in particular, xylitol, sorbitol or mannitol, or sugars such as, in particular, sucrose, or alkoxylated derivatives of the abovementioned alcohols or mixtures of the abovementioned alcohols.

[0073] Preferably, the content of the polymer according to the invention in the moisture-curing polyurethane composition is at least 25% by weight, preferably at least 40% by weight and in particular at least 60% by weight, based on the total amount of isocyanate group-containing polymers in the composition.

[0074] Preferably, the moisture-curing polyurethane composition further comprises at least one branched component containing isocyanate groups and having an average NCO functionality of more than 2. Together with the polymers according to the invention, this enables good mechanical strength and thermal stability as well as good adhesion to plastic substrates.

[0075] Preferably, the branched component containing isocyanate groups is selected from oligomeric diisocyanates and branched polymers containing isocyanate groups.

[0076] Preferably, the average —NCO functionality of the isocyanate group-containing branched components is from 2.2 to 4, in particular from 2.3 to 3.5.

[0077] Preferably, the oligomeric diisocyanate is HDI-biuret such as N 100 or N 3200 (from Covestro), HDB or HDB-LV (from Vencorex) or 24A-100 (from Asahi Kasei); HDI-isocyanurates, such as N 3300, N 3600 or N 3790 BA (all from Covestro), HDT, HDT-LV or HDT-LV2 (from Vencorex), TPA-100 or THA-100 (from Asahi Kasei) or HX (from Nippon Polyurethane); HDI - uretdione such as N 3400 (from Covestro); HDI-iminooxadiazinedione such as XP2410 (from Covestro); HDI-allophanates such as VP LS 2102 (from Covestro); IPDI-isocyanurate, e.g. in solution Z 4470 (from Covestro) or solid form T1890 / 100 (from Evonik); TDI-oligomers such as IL (from Covestro); and mixed TDI / HDI-based isocyanurates, such as HL (from Covestro), where "HDI" stands for 1,6-hexane diisocyanate, "IPDI" stands for isophorone diisocyanate and "TDI" stands for 2,4-toluene diisocyanate or a mixture thereof with 2,6-toluene diisocyanate.

[0078] Preferably, the average NCO functionality of the branched polymer containing isocyanate groups is from 2.2 to 3, in particular from 2.3 to 3.

[0079] Particularly preferred branched polymers containing isocyanate groups have an NCO content of 1 to 2.5% by weight and a monomeric diisocyanate content of up to 0.3% by weight and are obtained by reacting 4,4′-MDI or IPDI, in particular 4,4′-MDI, with optionally ethylene oxide-terminated polyoxypropylene triols having an average OH functionality of 2.2 to 3 and an OH value 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, followed by removal of the majority of the unconverted monomeric diisocyanate.

[0080] Another particularly preferred branched polymer containing isocyanate groups is a conventionally prepared polymer having an NCO content of 1.2 to 2.5% by weight, obtained by reacting at least one monomeric diisocyanate with at least one polyoxypropylene triol and optionally at least one polyoxypropylene diol in an NCO / OH ratio of 1.5 / 1 to 2.2 / 1, wherein the triol and diol optionally contain some 1,2-ethylene oxide groups. Preferred monomeric diisocyanates for this purpose are 4,4′-MDI, TDI or IPDI.

[0081] In addition to the polymer according to the invention, the moisture-curing polyurethane composition may also contain at least one further linear polymer containing isocyanate groups. Particularly preferred polymers for this purpose have an NCO content of 1.6 to 2.4% by weight, in particular 1.6 to 2.1% by weight, and a monomeric diisocyanate content of up to 0.3% by weight, obtained by reacting 4,4′-MDI with optionally ethylene oxide-terminated polyoxypropylene diols 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 the majority of the unreacted 4,4′-MDI as described above.

[0082] Preferably, the moisture-curing polyurethane composition comprises the linear polymer and the branched component containing isocyanate groups in a weight ratio of 60 / 40 to 99 / 1, preferably 70 / 30 to 98 / 2. In this range, there is a particularly attractive combination of excellent mechanical properties and good adhesion to plastic substrates.

[0083] If the moisture-curing polyurethane composition comprises at least one oligomeric diisocyanate, the weight ratio between linear polymer and oligomeric diisocyanate is preferably from 90 / 10 to 99.5 / 0.5, preferably from 95 / 5 to 99 / 1, in particular from 95 / 5 to 98 / 2.

[0084] If the moisture-curing polyurethane composition comprises at least one branched polymer containing isocyanate groups, the weight ratio between linear polymer and branched polymer is preferably from 60 / 40 to 95 / 5, in particular from 70 / 30 to 90 / 10.

[0085] In one embodiment of the present invention, the moisture-curable polyurethane composition preferably further comprises at least one blocked amine.

[0086] Suitable blocked amines preferably have at least one aldimino or oxazolidinyl group. On contact with moisture, they react with the isocyanate groups present and simultaneously hydrolyze and release the amino groups, and can promote rapid, bubble-free curing, a particularly non-tacky surface and / or particularly good mechanical properties.

[0087] Preferred oxazolidines are bisoxazolidines, in particular bisoxazolidines derived from isobutyraldehyde, benzaldehyde or substituted benzaldehydes, in particular benzaldehydes substituted in the para position by an optionally branched alkyl group having 10 to 14 carbon atoms.

[0088] Preference is given to bis-oxazolidines obtained by reaction of OH-functional mono-oxazolidines with diisocyanates, in particular 1,6-hexamethylene diisocyanate. Suitable mono-oxazolidines are obtained in particular by reaction of diethanolamine with aldehydes with simultaneous liberation and removal of water.

[0089] Suitable aldimines are, in particular, dialdimines or trialdimines obtainable by reaction of commercially available primary diamines or triamines with nonenolizable aldehydes. These are aldehydes which have no hydrogen atom in the alpha position to the carbon atom of the aldehyde group.

[0090] Particularly preferred blocked amines are selected from N,N'-bis(2,2-dimethyl-3-lauroyloxypropylene)hexylene-1,6-diamine, N,N'-bis(2,2-dimethyl-3-acetoxypropylene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine, N,N'-bis(2,2-dimethyl-3-lauroyloxypropylene)-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 n N,N'-bis(2,2-dimethyl-3-acetoxypropylene)polyoxypropylene diamine with an average molecular weight of 450 to 750 g / mol n N,N'-bis(2,2-dimethyl-3-lauroyloxypropylene)polyoxypropylene diamine with an average molecular weight of 750 to 1050 g / mol n N,N'-bis(benzylidene)polyoxypropylene diamine with an average molecular weight of 380 to 680 g / mol n 680 to 1100 g / mol of N,N'-bis(4-C 10-14 -alkylbenzylidene) polyoxypropylene diamine, average molecular weight M n N,N',N"-tri(2,2-dimethyl-3-acetoxypropylene)polyoxypropylenetriamine having an average molecular weight of 730 to 880 g / mol and an average molecular weight of n The N,N',N"-tris(2,2-dimethyl-3-lauroyloxypropylene)polyoxypropylene triamine is 1150 to 1300 g / mol.

[0091] The moisture-curable polyurethane composition preferably further comprises at least one other ingredient selected from the group consisting of a catalyst, a filler, a plasticizer and a stabilizer.

[0092] Suitable catalysts are catalysts for accelerating the reaction of isocyanate groups, in particular organotin(IV) compounds such as, in particular, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dibutyltin diacetylacetonate, dimethyltin dilaurate, dioctyltin diacetate, dioctyltin dilaurate or dioctyltin diacetylacetonate, complexes of bismuth(III) or zirconium(IV), in particular their complexes with ligands selected from the group consisting of alkoxides, carboxylates, 1,3-diketonates, hydroxyquinolinates, 1,3-ketoesters and 1,3-ketoamides, or compounds containing tertiary amino groups such as, in particular, 2,2′-dimorpholinodiethyl ether (DMDEE).

[0093] If the moisture-curing polyurethane composition contains blocked amines, suitable catalysts are also catalysts for the hydrolysis of blocked amino groups, in particular organic acids, in particular aromatic carboxylic acids such as benzoic acid, 2-nitrobenzoic acid or salicylic acid.

[0094] In particular, combinations of different catalysts are also suitable.

[0095] Suitable fillers are, in particular, ground or precipitated calcium carbonate, optionally coated with fatty acids, in particular stearates, barite (settled stone), quartz powder, quartz sand, dolomite, wollastonite, calcined kaolin, layered silicates such as mica or talc, zeolites, aluminum hydroxide, magnesium hydroxide, silicon dioxide (including highly disperse silicon dioxide from pyrolytic processes), cement, gypsum, fly ash, industrially produced carbon black, graphite, metal powders such as aluminum, copper, iron, silver or steel, PVC powder or hollow spheres.

[0096] Preference is given to calcium carbonate optionally coated with fatty acids, in particular stearates, calcined kaolin or industrially produced carbon black.

[0097] Suitable plasticizers are, in particular, carboxylic acid esters, for example phthalates, in particular diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) or di(2-propylheptyl)phthalate (DPHP), hydrogenated phthalates or 1,2-cyclohexanedicarboxylates, in particular hydrogenated diisononyl phthalate or diisononyl-1,2-cyclohexanedicarboxylate (DINCH), terephthalates, in particular bis(2-ethylhexyl)terephthalate (DOTP) or diisononyl terephthalate (DINT), hydrogenated terephthalates or 1,4-cyclohexanedicarboxylates, in particular hydrogenated bis(2 1,4-cyclohexanedicarboxylate, diisononyl terephthalate ...

[0098] Suitable stabilizers are in particular stabilizers against oxidation, heat, light or UV rays. Preferably, the composition comprises at least one UV stabilizer.

[0099] The moisture-curing polyurethane composition may contain other additives, in particular

[0100] - inorganic or organic pigments, in particular titanium dioxide, chromium oxide or iron oxide;

[0101] - fibers, in particular glass fibers, carbon fibers, metal fibers, ceramic fibers, plastic fibers, for example polyamide fibers or polyethylene fibers, or natural fibers, for example wool, cellulose, hemp or sisal;

[0102] - nanofillers such as graphene or carbon nanotubes;

[0103] -dye;

[0104] - drying agents, in particular molecular sieves, calcium oxide, highly reactive isocyanates such as p-toluenesulfonyl isocyanate, monooxazolidines such as 2 (from Incorez) or orthoformate;

[0105] - adhesion promoters, in particular organoalkoxysilanes, in particular epoxysilanes such as in particular 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane, (meth)acryloylsilanes, anhydridesilanes, carbamatesilanes, alkylsilanes or iminosilanes, or oligomeric forms of these silanes, or titanates;

[0106] - other catalysts which accelerate the reaction of isocyanate groups;

[0107] - rheology modifiers, in particular thickeners, in particular layered silicates such as bentonites, castor oil derivatives, hydrogenated castor oil, polyamides, polyamide waxes, polyurethanes, urea compounds, pyrogenic silicas, cellulose ethers or hydrophobically modified polyoxyethylenes;

[0108] - 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 propionate, butyral, 2-ethylhexane acetal, dioxolane, glycerol formal or 2,5,7,10-tetraoxadodecane (TOU), toluene, xylene, heptane, octane, naphtha, white spirit, petroleum ether or gasoline, in particular Solvesso TM -type (from Exxon), and propylene carbonate, dimethyl carbonate, butyrolactone, N-methylpyrrolidone, N-ethylpyrrolidone, p-chlorobenzotrifluoride or benzotrifluoride;

[0109] - natural resins, fats or oils such as rosin, shellac, linseed oil, castor oil or soybean oil;

[0110] - non-reactive polymers, in particular homopolymers or copolymers of unsaturated monomers, in particular selected from ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate or alkyl (meth)acrylates, in particular polyethylene (PE), polypropylene (PP), polyisobutylene, ethylene vinyl acetate copolymers (EVA) or atactic poly-α-olefins (APAO);

[0111] - flame retardant substances, in particular the fillers already mentioned, such as aluminum hydroxide or magnesium hydroxide or organic phosphates;

[0112] - Additives, in particular wetting agents, leveling agents, defoamers, deaerators or biocides;

[0113] or other materials commonly used in moisture-curing polyurethane compositions.

[0114] It may be desirable for certain materials to be chemically or physically dried prior to being incorporated into the composition.

[0115] When mixing the isocyanate group-containing polymers according to the invention with other constituents of the composition, in particular fillers, the content of monomeric diisocyanates can optionally be further reduced by reaction with the moisture present.

[0116] The moisture-curable polyurethane composition preferably comprises

[0117] 30 to 70% by weight of polymers containing isocyanate groups, of which 10 to 70% by weight are polymers according to the invention,

[0118] - 20 to 60% by weight of fillers,

[0119] - 0 to 25% by weight, in particular 0 to 10% by weight, of plasticizers,

[0120] and optionally other ingredients, in particular oligomeric diisocyanates, blocked amines or catalysts.

[0121] Moisture-curable polyurethane compositions have high strength and high elongation after curing.

[0122] The tensile strength determined as described in the examples is preferably at least 1.5 MPa, particularly preferably at least 2 MPa, in particular at least 2.5 MPa.

[0123] The modulus of elasticity in the range of 0.05 to 5% elongation, determined as described in the examples, is preferably from 2 to 20 MPa, in particular from 3 to 15 MPa.

[0124] The elongation at break determined as described in the examples is preferably at least 300%, in particular at least 500%.

[0125] The moisture-curing polyurethane composition is prepared in particular under the exclusion of moisture and stored in watertight containers at ambient temperature. Suitable watertight containers are made in particular of optionally coated metal and / or plastic and are in particular barrels, containers, bottles, buckets, barrels, cans, bags, hose bags, magazines or tubes.

[0126] The moisture-curing polyurethane composition may be present in the form of a one-component composition or in the form of a multi-component (especially a two-component) composition.

[0127] "One-component" means a composition in which all ingredients of the composition are present in the same container and is inherently storage stable.

[0128] “Two-component” refers to a composition whose components are present in two different components which are stored in separate containers and are not mixed with one another until immediately before or during application of the composition.

[0129] The moisture-curable polyurethane composition is preferably a one-component composition and is generally storage-stable for a period of several months to a year or more in suitable packaging and storage.

[0130] When the moisture-curing polyurethane composition is applied, the curing process begins. The result is a cured composition.

[0131] In the case of a one-component composition, the composition is applied in its own form and then begins to cure under the action of moisture or water. To accelerate curing, an accelerator component containing or releasing water and / or a catalyst and / or a curing agent can be admixed into the composition during application or the composition can be brought into contact with the accelerator component after application.

[0132] During curing, the isocyanate groups react with one another under the influence of moisture. In the case of moisture-curing polyurethane compositions containing blocked amines, the isocyanate groups also react with the hydrolyzed blocked amino groups. The overall reaction of the isocyanate groups that results in the curing of the composition is also referred to as crosslinking.

[0133] The moisture required for the curing of the moisture-curing polyurethane composition preferably enters the composition from the air (air moisture) by diffusion. A solid layer ("skin") of the cured composition is formed on the surface of the composition in contact with the air. Curing is carried out along the diffusion direction from the outside to the inside, wherein the skin becomes thicker and thicker and eventually contains all the applied composition. Moisture can also enter the composition additionally or completely from one or more substrates on which the composition is applied and / or originate from the accelerator component, which is mixed into the composition at the time of application or is in contact with the mixture after application (e.g. by painting or spraying).

[0134] The moisture-curing polyurethane composition is preferably applied at ambient temperature, in particular in the range of about -10 to 50°C, preferably -5 to 45°C, in particular 0 to 40°C.

[0135] Curing of the moisture-curing polyurethane composition is also preferably carried out at ambient temperature.

[0136] Moisture-cure polyurethane compositions have a long processing time (open time) and a rapid cure.

[0137] If the moisture-curing polyurethane composition contains blocked amines, the aldehyde used to block the amino groups is released during crosslinking. If the aldehyde is substantially nonvolatile, it remains largely in the cured composition and acts as a plasticizer.

[0138] The moisture-curing polyurethane compositions are preferably used as elastic adhesives or elastic sealants or elastic coatings.

[0139] As adhesives and / or sealants, the moisture-curing polyurethane compositions are particularly suitable for bonding and sealing applications in the construction industry and the manufacturing industry or in automotive construction, in particular for splicing floor bonding, assembly, mounting bonding, module bonding, window bonding, seam sealing, body sealing, gap sealing or cavity sealing.

[0140] Elastic bonding in automobile construction is, for example, the bonding of components such as plastic covers, trims, flanges, bumpers, cockpits or other mounted parts to the painted body of a vehicle, or the bonding of windows into a vehicle, in particular a car, a truck, a bus, a rail vehicle or a ship.

[0141] As a sealant, the moisture-curing polyurethane composition is particularly suitable for elastic sealing of all types of joints, gaps or cavities, in particular building joints, such as expansion joints or connection joints between components (in particular plastic components), or ground joints in underground buildings. In particular, for the sealing of expansion joints in buildings, sealants with soft elastic properties and very high cold flexibility are particularly suitable.

[0142] As coatings, the moisture-curing polyurethane compositions are particularly suitable for protecting and / or sealing buildings or parts thereof, in particular in the field of plastic materials, in particular for balconies, terraces, roofs, in particular flat roofs or slightly sloping roof surfaces or roof gardens, or for use in building interiors under tiles or ceramic slabs in sinks or kitchens, or for collecting tanks, channels, shafts, silos, water tanks or wastewater treatment systems.

[0143] It can also be used for repair purposes as a sealant or coating, for example, for unsealed roof membranes or floor coverings that are no longer suitable, or as a repair material for highly reactive spray sealants.

[0144] The moisture-curable polyurethane compositions can be formulated to have a paste-like consistency having structural viscous properties.

[0145] Such a composition may be applied by suitable means, for example from a commercially available cartridge or drum or bottle, for example in the form of a bead, which may have a substantially circular or triangular cross-section.

[0146] The moisture-curing polyurethane composition can also be formulated as a liquid and so-called self-leveling, or only slightly thixotropic and can be applied by pouring. As a coating, the composition can then be distributed in a flat form to the desired layer thickness, for example by means of a roller, scraper, spatula or scraper. In the course of work, a layer thickness of 0.5 to 3 mm, in particular 1 to 2.5 mm, is usually applied.

[0147] The moisture-curing polyurethane compositions are preferably used as elastic adhesives or elastic sealants or elastic coatings for bonding, sealing or coating at least one plastic substrate.

[0148] Suitable plastic substrates are, in particular, hard and soft PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM, EPDM or blends of polycarbonate, and other plastics, such as, in particular, ABS and / or SAN, each of which may be present in untreated form or in the form of a surface treatment, for example by plasma, corona or flame, and fiber-reinforced plastics, such as, in particular, carbon fiber-reinforced plastics (CFK), glass fiber-reinforced plastics (GFK) or sheet molding compounds (SMC).

[0149] The plastic substrate is preferably 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 other plastics, such as in particular ABS and / or SAN.

[0150] Preferred among these are rigid PVC, polycarbonate, blends of polycarbonate with ABS and / or SAN, PMMA or ABS, in particular polycarbonate or blends of polycarbonate. These plastics are particularly important in view of their good adhesion without complicated pretreatment and can be bonded particularly frequently.

[0151] Suitable further substrates which can be bonded or sealed or coated with the moisture-curing polyurethane composition are, in particular:

[0152] - metals or alloys, such as aluminium, copper, iron, steel, non-ferrous metals, including metals or alloys with surface treatments, such as zinc- or chromium-plated metals;

[0153] - coated or painted substrates, in particular painted tiles, coated concrete, powder-coated metals or alloys or painted sheets;

[0154] - Paints or lacquers, especially automotive finishes.

[0155] - glass, glass ceramics, concrete, mortar, cement flooring, fiber cement, in particular fiber cement board, brick, tile, gypsum, in particular gypsum board or dry flooring, or natural stone such as granite or marble;

[0156] - Repair or levelling materials based on PCC (polymer modified cement mortar) or ECC (epoxy modified cement mortar);

[0157] - tar or bitumen;

[0158] - leather, fabric, paper, wood, wooden materials combined with resins (for example phenolic resins, melamine resins or epoxy resins), resin-fabric composites or other so-called polymer composites;

[0159] - Insulating foams, in particular, made of EPS, XPS, PUR, PIR, asbestos, glass wool or expanded glass (cellular glass).

[0160] If desired, the substrate can be pretreated before application, in particular by physical and / or chemical cleaning methods or by applying an activator or primer.

[0161] Two identical substrates or two different substrates may be bonded and / or sealed.

[0162] The moisture-curing polyurethane composition is preferably used in a bonding or sealing method comprising the following steps:

[0163] (i) applying the moisture-curable polyurethane composition to

[0164] - a first substrate and during the open time of the composition, the composition is brought into contact with a second substrate, or

[0165] - onto a first substrate and a second substrate and join the two substrates during the open time of the composition, or

[0166] - between two substrates,

[0167] (ii) Curing the composition by contact with moisture.

[0168] The moisture-curing polyurethane composition is also preferably used in a bonding or sealing method comprising the following steps:

[0169] (i) applying the moisture-curable polyurethane composition to a substrate,

[0170] (ii) Curing the composition by contact with moisture.

[0171] In the method, preferably at least one substrate is a plastic substrate as described above.

[0172] The article bonded or sealed or coated with the composition is obtained by applying and curing the moisture-curing polyurethane composition. The article can be a building or a part thereof, in particular a building, a roof, a stairwell or a facade of an above-ground or underground building, or can be an industrial good or a consumer good, in particular a window, a lamp, a traffic light, a household machine or a means of transport such as in particular a car, a bus, a trailer, a truck, a rail vehicle, a ship, an airplane or a helicopter, or a part thereof, for example a window made of plexiglass, a panoramic sunroof or a lampshade.

[0173] Another subject of the invention is a cured composition obtained by contacting the moisture-curing polyurethane composition with moisture.

[0174] Another subject of the invention is an adhesively bonded composite comprising at least one plastic substrate and a composition as described above which cures by contact with moisture.

[0175] Example

[0176] Examples are described below which explain the invention in more detail. The invention is of course not limited to the examples described.

[0177] "Standard climate" ("NK") means a temperature of 23±1° C. and a relative air humidity of 50±5%.

[0178] If not stated otherwise, the chemicals used were obtained from Sigma-Aldrich.

[0179] The viscosity was measured using a thermostatic cone-plate viscometer Rheotec RC30 (cone diameter 25 mm, cone angle 1°, distance from cone tip to plate 0.05 mm, shear rate 10 s -1 ) for measurement.

[0180] The monomeric diisocyanate content was determined by HPLC (detection by photodiode array; 0.04 M sodium acetate / acetonitrile as mobile phase) after previous derivatization by N-propyl-4-nitrobenzylamine.

[0181] Polyols used:

[0182] 4200: Polyoxypropylene glycol, OH value 28 mg KOH / g (from Covestro)

[0183] 8200N: Polyoxypropylene glycol, OH value 14 mg KOH / g (from Covestro)

[0184] 12200N: Polyoxypropylene glycol, OH value 10 mg KOH / g (from Covestro)

[0185] 5031 BT: Ethylene oxide terminated polyoxypropylene triol, OH value 28 mgKOH / g (from Covestro)

[0186] Monomeric diisocyanates used:

[0187] 44 MC L: 4,4'-diphenylmethane diisocyanate, NCO content 33.6% by weight (from Covestro)

[0188] Preparation of polymers containing isocyanate groups:

[0189] Polymer L1 (linear):

[0190] Make 757.7g (0.19eq OH) 8200N and 242.3g (1.9eq NCO) 44MC L was reacted by known methods at 80° C. to form a polymer having an NCO content of 7.2% by weight, a viscosity of 6.8 Pa·s at 20° C. and a monomeric 4,4′-diphenylmethane diisocyanate content of about 20% by weight.

[0191] Subsequently, the volatile components, in particular the majority of the monomeric 4,4'-diphenylmethane diisocyanate, were distilled off in a short-path evaporator (jacket temperature 180° C., pressure 0.1 to 0.005 mbar, condensation temperature 47° C.). The linear polymer thus obtained had an NCO content of 1.0% by weight, a viscosity of 25.0 Pa·s at 20° C. and a content of monomeric 4,4'-diphenylmethane diisocyanate of 0.06% by weight.

[0192] Polymer L2 (linear):

[0193] Make 812.0g (0.15eq OH) 12200N and 188.0g (1.5eq NCO) 44MC L was reacted by known methods at 80° C. to form a polymer having an NCO content of 5.6% by weight, a viscosity of 13.9 Pa·s at 20° C. and a monomeric 4,4′-diphenylmethane diisocyanate content of about 14% by weight.

[0194] Subsequently, the volatile components, in particular the majority of the monomeric 4,4'-diphenylmethane diisocyanate, were distilled off in a short-path evaporator (jacket temperature 180° C., pressure 0.1 to 0.005 mbar, condensation temperature 47° C.). The linear polymer thus obtained had an NCO content of 0.7% by weight, a viscosity of 29.4 Pa·s at 20° C. and a content of monomeric 4,4'-diphenylmethane diisocyanate of 0.04% by weight.

[0195] Polymer Ref-1 (linear, control):

[0196] Make 727.0g 4200 and 273.0g 44MC L was reacted according to known methods at 80° C. to form a polymer having an NCO content of 7.4% by weight, a viscosity of 5.2 Pa·s at 20° C. and a monomeric 4,4′-diphenylmethane diisocyanate content of about 17% by weight.

[0197] Subsequently, the volatile components, in particular the majority of the monomeric 4,4'-diphenylmethane diisocyanate, were distilled off in a short-path evaporator (jacket temperature 180° C., pressure 0.1 to 0.005 mbar, condensation temperature 47° C.). The linear polymer thus obtained had an NCO content of 1.8% by weight, a viscosity of 13.3 Pa·s at 20° C. and a content of monomeric 4,4'-diphenylmethane diisocyanate of 0.08% by weight.

[0198] Polymer C-1 (branched):

[0199] Make 725.0g 5031BT and 275g 44MC L reacts according to known methods at 80° C. to form a polymer having an NCO content of 7.6% by weight, a viscosity of 6.5 Pa·s at 20° C. and a monomeric 4,4′-diphenylmethane diisocyanate content of about 20% by weight.

[0200] Subsequently, the volatile components, in particular the majority of monomeric 4,4'-diphenylmethane diisocyanate, were distilled off in a short-path evaporator (jacket temperature 180° C., pressure 0.1 to 0.005 mbar, condensation temperature 47° C.). The polymer thus obtained had an NCO content of 1.7% by weight, a viscosity of 19 Pa·s at 20° C. and a content of monomeric 4,4'-diphenylmethane diisocyanate of 0.04% by weight.

[0201] Moisture-curing polyurethane composition:

[0202] Compositions Z1 to Z7:

[0203] For each composition, the mixture was mixed with a centrifugal mixer (SpeedMixer TM DAC 150, FlackTek Inc.) was used to mix the ingredients given in Table 1 in the given amounts (parts by weight) at 3000 rpm for one minute with exclusion of moisture and stored with exclusion of moisture. Each composition was tested as follows:

[0204] The Shore A hardness was determined in accordance with DIN 53505 on test specimens cured for 14 days in standard climate.

[0205] To determine the mechanical properties, the composition was cast onto silicone-coated release paper to form a 2 mm thick film, the film was stored in a standard climate for 14 days, dumbbell-shaped specimens with a length of 75 mm, a stem length of 30 mm and a stem width of 4 mm were punched out of the film and the tensile strength (breaking force), elongation at break and modulus of elasticity (at 0.5-5% elongation) were measured at a tensile speed of 200 mm / min in accordance with DIN EN 53504.

[0206] The adhesiveness to the plastic substrate is determined by applying the composition in the form of four parallel adhesive strips with a width of about 10 mm, a height of 5 mm and a length of 15 mm to the corresponding substrate and curing for 7 days under standard climate. Then the adhesiveness of the cured composition is tested for the first time by cutting the first adhesive strip at the narrow end just above the adhesive surface, clamping the cut end of the adhesive strip with round tweezers and trying to tear the adhesive strip from the substrate. Then the adhesive strip is cut again until the substrate, wherein the cut portion is rolled up with round tweezers, and the adhesive strip is tried again to be torn off from the substrate. Therefore, the entire adhesive strip is cut off from the substrate in a pulling manner. Then the adhesiveness is evaluated according to the fracture pattern, and is recorded as "7d NK" in Table 1. Then a portion of the sample is immersed in deionized water and stored for 7 days, then stored for 2 hours under standard climate, and then the second adhesive strip is cut off from the substrate by pulling with round tweezers, and the adhesiveness is evaluated according to the fracture pattern, and is recorded as "7d H2O" in Table 1. The specimens were then stored in a circulating air oven at 80°C for 24 hours, then in a standard climate for 2 hours, and then the adhesion of the third strip was tested as described above, the adhesion was evaluated according to the fracture pattern, and is recorded as "1d 80°C" in Table 1. Finally, the specimens were stored at 70°C and 100% relative humidity for 7 days, then in a standard climate for 2 hours, and the adhesion of the fourth strip was tested as described above, the adhesion was evaluated according to the fracture pattern, and is recorded as "7d 70°C / 100% rF" in Table 1.

[0207] The plastic substrate used was the following plastic sheet (300x200x2mm):

[0208] PMMA: XT 0A000 (from Evonik )

[0209] PC: GP clear 099 (uncoated polycarbonate from Covestro)

[0210] ABS: Metzoplast ABS / G (from Metzeler Plastics GmbH)

[0211] PVC: ES (from Kunststoffe

[0212] Adhesion was assessed according to the following scale:

[0213] 100 represents over 95% cohesive failure, meaning excellent adhesion.

[0214] ..40 represents 40% cohesive failure, meaning moderate adhesion.

[0215] 5 represents 5% cohesive failure, meaning insufficient adhesion.

[0216] 0 represents 0% cohesive failure (100% adhesive failure), meaning poor adhesion.

[0217] The results are listed in Table 1.

[0218] Comparative Examples are denoted by (Ref.).

[0219]

[0220]

[0221] Table 1: Composition (parts by weight) and properties of Z1 to Z7.

[0222] 1 p-Toluenesulfonyl isocyanate

[0223] 2 5 GU (from Omya)

[0224] 3 R 972 (from Evonik)

[0225] 4 2,2'-Dimorpholinodiethyl ether

Claims

1. A linear polymer containing isocyanate groups, said polymer having an NCO content of 0.3 to 1.5% by weight and a monomeric diisocyanate content of up to 0.5% by weight, characterized in that The polymers are obtained by reacting at least one monomeric aromatic diisocyanate and a polyether diol in an NCO / OH ratio of 6 / 1 to 15 / 1 and subsequently removing the majority of the monomeric aromatic diisocyanate by suitable separation methods, the polyether diol having an OH number of 5 to 21 mg KOH / g.

2. The polymer according to claim 1, characterized in that The monomeric aromatic diisocyanate is 4,4'-diphenylmethane diisocyanate.

3. The polymer according to any one of claims 1 to 2, characterized in that The polyether diol contains 80 to 100% by weight of 1,2-propylene oxide groups and 0 to 20% by weight of 1,2-ethylene oxide groups.

4. The polymer according to any one of claims 1 to 2, characterized in that The polyetherdiols have an OH number of 6 to 19 mgKOH / g and an average OH functionality of at least 1.

9.

5. The polymer according to any one of claims 1 to 2, characterized in that Excess monomeric diisocyanate is removed by distillation.

6. The polymer according to any one of claims 1 to 2, characterized in that The polymers have an NCO content of 0.5 to 1.3% by weight and a monomeric diisocyanate content of up to 0.3% by weight.

7. The polymer according to any one of claims 1 to 2, characterized in that The NCO content is at least 90% of the theoretical NCO content, calculated from the addition of one mole of monomeric diisocyanate per mole of OH groups of the polyetherdiol.

8. The polymer according to claim 1 or 2, characterized in that The polyetherdiols have an OH number of 12 to 14 mg KOH / g and an average OH functionality of at least 1.

9.

9. A moisture-curing polyurethane composition comprising a polymer according to any one of claims 1 to 8, said composition having a monomeric diisocyanate content of less than 0.1% by weight.

10. The moisture-curable polyurethane composition according to claim 9, characterized in that The composition has a content of 5 to 80% by weight of the polymer according to any one of claims 1 to 8, based on the entire composition.

11. The moisture-curing polyurethane composition according to any one of claims 9 to 10, characterized in that The composition has a content of at least 25% by weight of the polymer according to any one of claims 1 to 8, based on the total amount of isocyanate group-containing polymers in the composition.

12. The moisture-curing polyurethane composition according to any one of claims 9 to 10, characterized in that The composition further comprises at least one component which contains isocyanate groups and has an average NCO functionality of greater than 2.

13. Use of the moisture-curing polyurethane composition according to any one of claims 9 to 12 as an elastic adhesive or elastic sealant or elastic coating for bonding, sealing or coating at least one plastic substrate.

14. The use according to claim 13, 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 resin, phenolic resin, PUR, POM, PE, PP, EPM, EPDM, and blends of polycarbonate with ABS and / or SAN.

15. The use according to claim 13, characterized in that The plastic substrate is selected from TPO.

16. A cured composition obtained from the moisture-curing polyurethane composition according to any one of claims 9 to 12 after contact with moisture.

17. An adhesively bonded composite comprising at least one plastic substrate and a moisture-curing polyurethane composition according to any one of claims 9 to 12 which cures by contact with moisture.

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