Polyurethane composition having reduced blistering and matte effect

Abstract

The present invention relates to a polyurethane composition comprising, on the basis of the total weight of the composition: A) 20-50 weight% of a polyurethane prepolymer PU, which is a reaction product of a polyether polyol with at least two aromatic polyisocyanates or mixture of the reaction products, wherein the polyether polyol includes a polyether dial and a polyether trioI, and the weight ratio of the polyether trial to the polyether dial ranges from 4: 1 to 13: 1; and B) 12.5% to 17.5% of carbon black on the basis of the total weight of the composition. Furthermore, the present invention also relates to the use of carbon black in polyurethane compositions for reducing blistering during curing and increasing matte effect.

Description

Polyurethane composition with reduced foaming and matte effect Field of the Invention

[0001] The present invention relates to the field of polyurethane adhesives and sealants, and in particular to a low TVOC polyurethane weather-resistant composition having reduced foaming during curing and a good matte effect.

[0002] Background of the Invention

[0003] Low total volatile organic compound (TVOC) emissions (i.e., low TVOC) are becoming increasingly stringent requirements for coatings, adhesives, and sealants used in construction and industrial manufacturing. Consequently, avoiding the use of volatile organic solvents in coating, adhesive, and sealant compositions is becoming a trend and also meets users' demand for environmental friendliness.

[0004] The crosslinked curable polyurethane composition of isocyanate group and hydroxyl group and / or moisture reaction is used in many industrial applications, for example, in construction and manufacturing industry, is used as adhesive, sealant or coating. When using this composition under high air humidity and / or the temperature that increases, because the carbon dioxide gas that releases, its solidification often forms interfering bubbles, and it can not dissolve or export quickly enough. In order to avoid foaming, chemically blocked amine can be added in the composition, i.e. so-called latent curing agent, it releases amino group and crosslinks quickly with isocyanate group and can not form carbon dioxide when it contacts with moisture. As latent curing agent, usually use the compound with aldimine, ketimine or oxazolidinyl group. However, known latent curing agent may be disadvantageous. For example, they can cause premature crosslinking reaction, and therefore reduce the storage stability of composition and / or its solidification is strongly accelerated thereby cause open time too short and therefore working window too short. In addition, many known latent curing agents can cause the troublesome discharge that is caused by volatile, strong-smelling aldehyde or ketone when solidifying, and described aldehyde or ketone is as blocking agent in latent curing agent and is released by hydrolysis.

[0005] Furthermore, in some specialized applications, coatings, adhesives, or sealant compositions are also required to have a matte finish. This is because a matte surface reduces visual distractions, making flaws and defects less noticeable than on glossy surfaces. Currently, matte finishes can be significantly reduced by adding fillers with matte properties, such as ultrafine silica and talc. Filler particle size significantly influences gloss, with larger particle sizes resulting in lower gloss. However, increasing the filler dosage can also reduce the product's smoothness and mechanical strength.

[0006] CN105733491A discloses a low-TVOC polyurethane weatherproof sealant. The polyurethane prepolymer contained in this polyurethane sealant is obtained by reacting a polyether polyol with an isocyanate. Suitable isocyanates include a variety of aliphatic or aromatic polyisocyanates, such as toluene diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate. Specifically, the document indicates that sealants prepared using aromatic isocyanates exhibit significantly poorer weathering properties than those prepared using aliphatic isocyanates. The document does not address how to reduce foaming during curing, nor does it mention a matte finish.

[0007] In addition, a highly weather-resistant, moisture-curable, one-component polyurethane composition is proposed in CN1507479A. In this composition, a blocked amine compound additive such as polyaldimine is added to provide sufficient curing properties and eliminate the problem of foaming during curing.

[0008] SUMMARY OF THE INVENTION

[0009] Therefore, an object of the present invention is to provide a polyurethane composition that reduces foaming during curing and achieves a matte finish. Furthermore, the composition reduces TVOC emissions and exhibits excellent weatherability and processability while maintaining or improving mechanical properties. In particular, the polyurethane composition according to the present invention can achieve reduced foaming during curing under high temperature and high humidity conditions in a simple manner, while being substantially free of blocked amine compounds such as polyaldimines.

[0010] Surprisingly, it has been found that this object can be achieved by a polyurethane composition as claimed in claim 1 .

[0011] In the polyurethane composition according to the present invention, the polyurethane prepolymer is, in particular, a reaction product obtained by reacting a polyether polyol component comprising a polyether diol and a polyether triol in a specific ratio with at least two aromatic polyisocyanates, or a mixture thereof. Compositions containing such a polyurethane prepolymer can particularly ensure excellent weather resistance.

[0012] The inventors have also discovered that the use of a certain amount of carbon black in the composition can further reduce foaming during curing, help improve weather resistance, and achieve a matte finish, without compromising the product's smoothness or mechanical strength. Surprisingly, this is achieved without the use of a latent curing agent such as a blocked amine compound.

[0013] In addition, no solvent may be used in the polyurethane composition of the present invention, thereby reducing the total VOC content.

[0014] 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.

[0015] Detailed Description of the Invention

[0016] The subject of the present invention is a polyurethane composition comprising, based on the total weight of the composition:

[0017] A) 20-50% by weight, preferably 25-40% by weight, of a polyurethane prepolymer PU, which is a reaction product or a mixture of reaction products of a polyether polyol and at least two aromatic polyisocyanates, wherein the polyether polyol comprises a polyether diol and a polyether triol and the weight ratio of the polyether triol to the polyether diol is in the range of 4:1 to 13:1; and

[0018] B) 12.5% ​​to 17.5%, preferably 13% to 16.5%, of carbon black.

[0019] Substance names beginning with "poly", such as polyols or polyisocyanates, denote in this context substances which formally contain two or more of the functional groups appearing in their names per molecule. The term "polymer" in this context includes, on the one hand, a collection of chemically identical macromolecules obtained by polymerization reactions (polyaddition, polyaddition, polycondensation) which differ in degree of polymerization, molecular weight and chain length. The term also includes, on the other hand, derivatives of the collection of macromolecules obtained by polymerization reactions, i.e. chemically identical or chemically non-identical compounds obtained by reaction (e.g. addition or substitution) of functional groups on predetermined macromolecules. The term also includes so-called prepolymers, i.e. reactive oligomeric preadducts whose functional groups participate in the construction of the macromolecule.

[0020] Isocyanate-terminated polymers are polymers or prepolymers having at least one terminal isocyanate group, in particular two terminal isocyanate groups.

[0021] The term "prepolymer" herein generally refers to an oligomer or polymer that is used as an intermediate in the production of a polymer having a higher molecular weight.

[0022] "Molecular weight" is understood herein as the molar mass of a molecule (in grams per mole). "Average molecular weight" denotes the number average Mn of a mixture of molecules in oligomeric or polymeric form, which is usually determined by gel permeation chromatography (GPC) relative to polystyrene standards. "Room temperature" herein denotes a temperature of 23°C.

[0023] The term "polyurethane polymers / prepolymers" includes all polymers or prepolymers produced by the so-called diisocyanate polyaddition process. This also includes those polymers or prepolymers which contain virtually or no urethane groups. Examples of polyurethane polymers / prepolymers are polyetherpolyurethanes, polyesterpolyurethanes, polyetherpolyureas, polyureas, polyesterpolyureas, polyisocyanurates and polycarbodiimides.

[0024] The polyurethane prepolymer (PU) according to the present invention is a reaction product or mixture of a polyether polyol and at least two aromatic polyisocyanates. The polyether polyol comprises a polyether diol and a polyether triol, and the weight ratio of the polyether triol to the polyether diol is in the range of 4:1 to 13:1, preferably 5:1 or 5.1:1 to 12:1. In the present invention, an excessively high polyether diol content may reduce the product's mechanical properties, while also compromising heat resistance and UV cracking resistance. Excessively high polyether triol content may result in insufficient toughness and reduced chalking resistance.

[0025] The polyurethane prepolymers PU suitable for preparing the compositions according to the invention are polymers or polymer mixtures obtainable by reacting the polyether polyols with at least two aromatic polyisocyanates, preferably diisocyanates. This reaction can be carried out by reacting the polyol and the polyisocyanate by conventional methods, for example at temperatures of 50° C. to 100° C., optionally with the use of a suitable catalyst, the polyisocyanate being metered in such a way that its isocyanate groups are present in a stoichiometric excess relative to the hydroxyl groups of the polyol.

[0026] In particular, the excess of aromatic polyisocyanate is selected such that, after reaction of all hydroxyl groups of the polyether polyol, an amount of 0.1 to 5% by weight, preferably 0.2 to 3% by weight, particularly preferably 0.3 to 2.5% by weight, of free isocyanate groups remains in the polyurethane polymer obtained.

[0027] Optionally, the polyurethane prepolymer PU can be prepared with the concurrent use of a plasticizer, wherein the plasticizer used does not contain groups reactive toward isocyanates.

[0028] Preferred are polyurethane prepolymers having the stated content of free isocyanate groups, obtained by reacting all diisocyanates with all polyether diols in an NCO:OH ratio of 1.3:1 to 4:1, in particular 1.5:1 to 3:1 and particularly preferably 1.7:1 to 2.5:1. Advantageously, the polyurethane prepolymer PU has a residual free NCO content of 1.0 to 2.5% by weight.

[0029] The polyether polyol used to prepare the polyurethane prepolymer PU of the present invention includes polyether diol and polyether triol, and is particularly preferably composed of polyether diol and polyether triol.

[0030] Particularly suitable polyether polyols (also known as polyoxyalkylene polyols or oligoether alcohols) are the polymerization products of ethylene oxide, 1,2-propylene oxide, 1,2- or 2,3-butylene oxide, oxetane, tetrahydrofuran or mixtures thereof, optionally with the aid of starter molecules having two or more active hydrogen atoms, such as water, ammonia or compounds having a plurality of OH- or NH- groups, such as 1,2-ethylene oxide. glycol, 1,2- and 1,3-propylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, the isomeric dipropylene glycol and tripropylene glycol, the isomeric butanediols, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, 1,3- and 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, aniline, and mixtures thereof. It is possible to use polyoxyalkylene polyols having a low degree of unsaturation (measured in accordance with ASTM D-2849-69 and expressed in milliequivalents of unsaturation per gram of polyol (mEq / g)), prepared, for example, with the aid of so-called double metal cyanide complex catalysts (DMC catalysts), but also polyoxyalkylene polyols having a higher degree of unsaturation, prepared, for example, with the aid of anionic catalysts such as NaOH, KOH, CsOH or alkali metal alcoholates.

[0031] Also suitable are ethylene oxide-terminated ("EO-endcapped") polyoxypropylene polyols. These are particularly polyoxypropylene polyoxyethylene polyols, which are obtained, for example, by further alkoxylating pure polyoxypropylene polyols, particularly polyoxypropylene diols and triols, with ethylene oxide after the polypropoxylation reaction, thereby imparting primary hydroxyl groups. In this case, polyoxypropylene polyoxyethylene diols and polyoxypropylene polyoxyethylene triols are preferred.

[0032] In a preferred embodiment, the polyether diol and polyether triol are selected from polyoxyethylene diol or triol, polyoxypropylene diol or triol, and polyoxypropylene polyoxyethylene diol or triol; in particular, polyoxyethylene diol, polyoxypropylene diol, polyoxyethylene triol and polyoxypropylene triol.

[0033] The polyols preferably have an average molecular weight of 250 to 30,000 g / mol, in particular 1,000 to 20,000 g / mol, and an average OH functionality in the range of 1.6 to 3. In particular, the molecular weight of the polyether diols is in the range of 3,000 to 5,000 g / mol, and the molecular weight of the polyether triols is in the range of 4,000 to 6,000 g / mol.

[0034] The compositions of the present invention may also optionally contain small amounts of other polyols (e.g., 1,2-ethanediol, 1,2- and 1,3-propylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, isomeric dipropylene glycol and tripropylene glycol, isomeric butanediols, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, The present invention also provides a polyurethane prepolymer having terminal isocyanate groups, obtained by reacting decanediol, undecanediol, 1,3- and 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, dimeric fatty alcohols, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, pentaerythritol, sugar alcohols such as xylitol, sorbitol or mannitol, sugars such as sucrose, other higher alcohols, low molecular weight alkoxylation products of the aforementioned diols and polyols, polyester polyols, and mixtures of the aforementioned alcohols with a polyisocyanate such as the polyisocyanates described above. In some advantageous embodiments of the present invention, only the polyether diols and triols described above can be used as the polyol component reacted with the polyisocyanate, that is, only the polyurethane prepolymer PU described above can be included as the polyurethane prepolymer in the composition.

[0035] In the polyurethane prepolymer (PU) according to the present invention, at least two aromatic polyisocyanates must be used. Contrary to some teachings in the prior art, the inventors have discovered that the use of at least two aromatic polyisocyanates in the polyurethane composition according to the present invention is crucial. Within the scope of the present invention, for example, a mixture of prepolymers or reaction products obtained by reacting two or more different aromatic polyisocyanates with corresponding polyether polyols can be used, or a reaction product obtained by reacting two or more different aromatic polyisocyanates simultaneously with corresponding polyether polyols can be used. Compared to aromatic polyisocyanates, aliphatic polyisocyanates or their prepolymers commonly used in the prior art generally react too slowly, failing to form crosslinks in a timely manner and being prone to cracking during aging. Furthermore, aliphatic polyisocyanates or their prepolymers can also lead to an increase in the TVOC content of the product. Furthermore, from the perspective of product weatherability, the inventors have discovered that using two or more aromatic polyisocyanates in the polyurethane prepolymer (PU) according to the present invention can result in a product with better weatherability than using a single aromatic polyisocyanate.

[0036] Suitable aromatic polyisocyanates are preferably diisocyanates, preferably selected from the group consisting of meta- and para-xylylenediisocyanate (meta- and para-XDI), meta- and para-tetramethyl-1,3-xylylene diisocyanate, meta- and para-tetramethyl-1,4-xylylene diisocyanate, bis-(1-isocyanato-1-methylethyl)-naphthalene, 2,4- and 2,6-toluene diisocyanate (TDI), 4,4'-, 2,4'- and 2,2'-toluene diisocyanate. -methylene diphenyl diisocyanate (MDI), 1,3- and 1,4-phenylenediisocyanate, 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene-1,5-diisocyanate (NDI), 3,3'-dimethyl-4,4'-diisocyanatobiphenyl (TODI) and mixtures and oligomers thereof; particularly preferably, the aromatic polyisocyanate is selected from a combination of 4,4'-, 2,4'- and 2,2'-methylene diphenyl diisocyanate (MDI) and 2,4- and 2,6-toluene diisocyanate (TDI).

[0037] In principle, the polyurethane prepolymer PU of the present invention can be produced from any reaction product. For example, the polyurethane prepolymer PU can be a reaction product produced by reacting a polyether triol, a polyether diol, and two aromatic polyisocyanates, such as MDI and TDI. It can also be produced by first reacting a polyether triol and / or diol with one of the two aromatic polyisocyanates, and then mixing the resulting reaction products. In a particularly preferred embodiment, the polyurethane prepolymer PU is a mixture of the reaction product of the above-mentioned polyether triol and MDI and the reaction product of the polyether triol and polyether diol with TDI.

[0038] In the polyurethane composition according to the present invention, the polyurethane prepolymer (PU) is present in an amount of 20-50% by weight, preferably 25-40% by weight, based on the total weight of the composition. If the polyurethane prepolymer content is too low, the product's storage stability may be affected; if the content is too high, the product's weather resistance may be affected.

[0039] Furthermore, the polyurethane composition of the present invention particularly needs to contain 12.5 to 17.5 wt %, preferably 13 to 16.5 wt %, of carbon black, based on the total weight of the composition.

[0040] Carbon black suitable for use in the present invention is a commonly used industrial product and is a loose, extremely fine black powder with a large specific surface area. Typically, carbon black is obtained by incomplete combustion or thermal decomposition of carbonaceous materials such as coal and natural gas in air-deficient conditions. It is commercially available, for example, as Cabot M570.

[0041] The inventors have discovered that adding the aforementioned specific amount of carbon black to the composition system according to the present invention can surprisingly reduce foaming during curing, particularly without the presence of a latent curing agent such as a blocked amine compound. Therefore, advantageously, the composition according to the present invention may contain less than 1% by weight, preferably less than 0.5% by weight, more preferably less than 0.1% by weight, and particularly preferably 0% by weight, based on the total weight of the composition, of a blocked amine compound-type latent curing agent, such as a polyaldimine. Such blocked amine compounds are essentially non-reactive with isocyanate groups, but instead form primary or secondary amino groups with moisture. Such blocked amine compounds include condensates of aldimines, ketimines, enamines, oxazolidines, and other aldehydes or ketones with compounds having at least one primary or secondary amino group and an active hydrogen, such as a primary or secondary amino group and a hydroxyl group. Furthermore, compounds having two or more oxazolidinyl groups in the molecule, prepared by reacting N-hydroxyoxazolidines with organic polyisocyanates, are also included. Furthermore, the inclusion of a specific amount of carbon black in the polyurethane composition according to the present invention can also help achieve a matte finish without compromising the mechanical properties of the product. However, the carbon black content required above is critical to achieving these effects. If the carbon black content is too low, it may cause bubbling of the product, while if the content is too high, it may affect the application performance, for example, it may make the extrusion force too high.

[0042] The composition preferably comprises further ingredients customary for polyurethane adhesives, in particular fillers other than carbon black, plasticizers, rheology additives, tackifiers, desiccants or stabilizers against UV rays and oxidation, and further customary admixtures.

[0043] The other fillers include one or a mixture of two or more of calcium carbonate, titanium dioxide, clay, talc, zinc oxide, glass balls, kaolin, silica powder, mica powder, polyamide, and PVC paste.

[0044] The polyurethane composition of the present invention may advantageously contain fillers including carbon black in an amount of 10-70 wt %, preferably 20-60 wt %, more preferably 35-55 wt %, based on the total weight of the composition.

[0045] The composition may particularly contain at least one plasticizer. Suitable plasticizers are, in particular, esters of organic carboxylic acids, in particular phthalates such as diisononyl phthalate or diisodecyl phthalate, hydrogenated phthalates such as diisononyl-1,2-cyclohexane dicarboxylate, adipates such as dioctyl adipate, azelate, and sebacate, or esters of organic phosphoric and sulfonic acids, or hydrocarbons such as polybutene or polyisobutene. Preferred plasticizers are phthalates, hydrogenated phthalates, or adipates. Most preferred are diisononyl phthalate, diisodecyl phthalate, or diisononyl-1,2-cyclohexane dicarboxylate.

[0046] The content of the plasticizer in the composition is preferably in the range of 5% to 40% by weight, in particular 10% to 30% by weight, particularly preferably 15% to 25% by weight, based on the entire composition.

[0047] Suitable adhesion promoters, in particular silane adhesion promoters, are organoalkoxysilanes ("silanes") having a reactive group on the organic radical, in particular epoxysilanes, mercaptosilanes, (meth)acryloylsilanes, isocyanatosilanes, anhydridesilanes, S-(alkylcarbonyl)-mercaptosilanes, aldiminosilanes or oligomeric forms of these silanes, or adducts of aminosilanes or mercaptosilanes with polyisocyanates. Preferred are 3-glycidyloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane or 3-methacryloyloxypropyltrimethoxysilane. Most preferred is 3-glycidyloxypropyltrimethoxysilane, which can be used, for example, A-187 was obtained commercially.

[0048] The content of the silane adhesion promoter in the composition is preferably in the range of 0.01% by weight to 1.0% by weight, in particular 0.05% by weight to 0.5% by weight, based on the entire composition.

[0049] The composition according to the present invention may also contain at least one amine catalyst. Suitable amine catalysts are tertiary amines, in particular those with low pKa values, preferably those with pKa values ​​between 12 and 7. Suitable amine catalysts are, for example, N-ethyl-diisopropylamine, N,N,N',N'-tetramethyl-alkylenediamine, 1,4-diazabicyclo[2.2.2]octane or triethylenediamine, and preferably 2,2'-dimorpholinodiethyl ether (DMDEE) and derivatives thereof having substituents on the morpholine ring. Particularly preferred are DMDEE and triethylenediamine.

[0050] The content of the amine catalyst in the composition is preferably in the range of 0.05% to 1.0% by weight, particularly 0.1% to 0.8% by weight, particularly preferably 0.15% to 0.6% by weight, based on the entire composition.

[0051] The composition can also preferably contain at least one metal catalyst. The metal catalyst can be added additionally or already present in the raw materials of the composition, for example, from the synthesis of a polyurethane polymer with isocyanate groups. Preferred metal catalysts are organotin (IV) compounds, organotitanates or organozirconates. Particularly preferred are organotin (IV) compounds. Suitable organotin (IV) compounds are in particular dialkyl tin oxides, dialkyl tin dichlorides, dialkyl tin dicarboxylates and dialkyl tin diketonates, preferably dibutyl tin oxide, dibutyl tin dichloride, dibutyl tin diacetate, dibutyltin dilaurate (DBTDL), dibutyl diacetylacetonate, dioctyl tin oxide, dioctyl tin dichloride, dioctyl tin diacetate, dioctyl tin dilaurate or dioctyl tin diacetylacetonate.

[0052] The content of the metal catalyst in the composition is preferably in the range of 0.001% by weight to 1.0% by weight, particularly 0.005% by weight to 0.1% by weight, based on the entire composition.

[0053] The content of any organotin(IV) compound used in the composition is preferably in the range from 0.001% to 0.2% by weight, in particular from 0.005% to 0.1% by weight, based on the entire composition.

[0054] The content of the light stabilizer in the composition is preferably in the range of 0.05% to 5.0% by weight, particularly 0.05% to 1.5% by weight, based on the entire composition. The composition further comprises a combination of a light-curable material selected from unsaturated acrylic compounds (preferably polyester acrylates) and a hindered amine light stabilizer.

[0055] The inventors have found that the use of one or more photocurable materials selected from unsaturated acrylic compounds together with a hindered amine light stabilizer in the composition according to the invention is particularly advantageous for improving weather resistance.

[0056] Photocurable materials readily undergo chemical changes in their molecular structure within a very short period of time upon exposure to light, accompanied by physical changes such as curing. Particularly suitable materials are unsaturated acrylic compounds, including acrylic acid and / or methacrylic acid monomers, oligomers thereof, and mixtures thereof, each containing one or more unsaturated groups. Polyester acrylate compounds, such as the commercially available Aronix M8060, are particularly preferred.

[0057] Hindered amine light stabilizers include UV absorbers (which absorb light energy such as that from sunlight and fluorescent lamps and convert it into harmless heat energy) and quenchers that quench the active centers triggered by light energy. Most of these hindered amine light stabilizers are commercially available, including, for example, ADEKASTAB LA-52, LA-57, LA-62, LA-67, LA-63, LA-68, LA-77, LA-82, and LA-87 (produced by ASAHI DENKA KOGYO). KK production); bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 1-methyl-8-(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 1-[2-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionyloxy]ethyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidinylsuccinate, dimethyl-1-(2-hydroxyphenyl)-

[0014] Examples of the present invention include poly(1,2,2,6,6-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl)[2,2,6,6-tetramethyl-4-piperidinyl]imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidinyl)imino]], di(1,2,2,6,6-pentamethyl-4-piperidinyl)2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butyl malonate, and mixtures thereof. Preferred examples include commercially available Tinuvin 292, which is a mixture of di(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate and 1-methyl-8-(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate.

[0058] In addition to the above, the composition according to the present invention may also contain other ingredients common to polyurethane adhesives. For example, the following ingredients:

[0059] - crosslinkers, for example oligomers or derivatives of diisocyanates, such as MDI, TDI, HDI or IPDI, in particular isocyanurates, carbodiimides, uretonimides, biuret, allophanate and iminooxadiazinedione, or mixtures of MDI and MDI homologues (polymeric MDI or PMDI);

[0060] - drying agents or dehydrating agents, for example p-tolyl isocyanate such as p-toluenesulfonyl isocyanate and other reactive isocyanates, calcium oxide or molecular sieves;

[0061] - rheology modifiers, for example thickeners, for example modified polyureas, polyamide waxes, polyethylene waxes, fibrous talc, castor oil derivatives, bentonites or fumed silicas as described as thixotropic agents ("thixotropy-imparting agents") in WO 02 / 48228 A2, pages 9 to 11;

[0062] - Stabilizers against heat, light and UV rays; flame retardants;

[0063] - surface-active substances, such as wetting agents, flow control agents, deaerators or defoamers;

[0064] - biocides, such as algaecides or fungicides;

[0065] and other substances commonly used in one-component compositions containing isocyanates, such as fibers, for example polyethylene fibers; dyes, pigments or other admixtures known to those skilled in the art.

[0066] In an advantageous embodiment, the composition contains less than 1 wt. %, preferably less than 0.5 wt. %, more preferably less than 0.1 wt. % of organic solvents, in particular organic solvents such as ketones, aromatic hydrocarbons, dimethylformamide, tetrahydrofuran, etc., based on the total weight of the composition.

[0067] The present invention also includes the use of the above-mentioned composition as a moisture-curing adhesive or sealant. The composition according to the invention is particularly suitable for application on concrete, mortar, bricks, tiles, plaster, natural stone such as granite or marble, glass, glass ceramics, screen-printed ceramics, metals or metal alloys, wood, plastics and painted materials.

[0068] The composition according to the invention preferably has a paste consistency with structurally viscous properties. The composition can be applied with the aid of a glue gun or a pump system, or extruded through a suitable glue nozzle.

[0069] Therefore, another aspect of the present invention relates to a method of bonding or sealing substrates comprising:

[0070] a) applying the composition according to the invention as described above to a first substrate;

[0071] b) providing a second substrate, optionally having applied thereto a composition according to the invention as described above;

[0072] c) contacting the first and second substrates with each other;

[0073] The first substrate and the second substrate are made of the same or different materials. Preferably, the first substrate and the second substrate are the same or different selected from glass, ceramic, concrete, mortar, metal profiles, wood, or plastic. More preferably, the composition is used to bond or seal vehicles and parts thereof, preferably automobiles and parts thereof.

[0074] After application, the composition according to the invention cures rapidly under the influence of moisture, optionally accelerated by heat, with simultaneous rapid crosslinking of the polyurethane prepolymer PU and the optionally included crosslinking agent and / or latent crosslinker. The moisture required for curing can originate from the air (atmospheric moisture), with the composition curing by diffusion of moisture from the outside to the inside. However, it is also possible to add an aqueous component to the composition, for example in the form of an aqueous paste, which is mixed with the composition in a homogeneous or heterogeneous manner, for example, using a static mixer.

[0075] The compositions according to the invention have a long shelf life, i.e., are storage-stable over an extended period. "Storage-stable" or "storable" means that the composition can be stored in a suitable container at room temperature for an extended period, typically at least 3 to 6 months and longer, without its application properties or usability (particularly viscosity, the push-out force required for application from the container, and the crosslinking rate) changing due to storage to an extent relevant to its use. This means, for example, that after 14 days of storage at 60°C (which results in accelerated aging), the push-out force of the composition according to the invention, measured at 23°C according to the method described below, is preferably increased by a factor of up to 3, particularly preferably by a factor of up to 2.5, and in particular by a factor of up to 2, compared to the push-out force of a freshly prepared composition that has been stored at 23°C for 7 days.

[0076] Finally, the invention also relates to a cured composition obtained from a composition as described above, after curing with water, in particular in the form of atmospheric moisture. Example

[0077] Examples are described below which explain the invention in more detail. The invention is of course not limited to the examples described.

[0078] Ingredients list

[0079]

[0080]

[0081] Test Method

[0082] Outdoor cracking performance: Use a phenix microscope to magnify 20 times to observe whether there are cracks on the film after outdoor exposure.

[0083] Outdoor black water flow performance: Observe with the naked eye whether there is any black mark under the rubber strip after outdoor exposure.

[0084] TVOC: The test method can refer to the VDA277 test standard for volatile organic compounds in non-metallic materials in automotive interiors.

[0085] Mattness: Apply a few grams of the composition to a cardboard paper with a layer thickness of about 2 mm and observe the glossiness of the surface with the naked eye. The degree of mattness is indicated by the amount of "+", while "-" indicates glossiness and no mattness.

[0086] Foaming: Apply two strips of the composition to two transparent glass plates, one 20 mm wide and 20 mm high, and the other 10 mm wide and 10 mm high. Then place them in a 60°C oven and a 40°C / 80% environmental chamber, respectively. After 10 days, cut the strips with a knife to check for bubbles.

[0087] Extrusion force: The composition was placed in an internally painted aluminum barrel (external diameter 46.9 mm, internal diameter 46.2 mm, length 215 mm, metric ISO thread M15×1.5 mm) and sealed airtight with a polyethylene stopper (diameter 46.1 mm) from Novelis Deutschland GmbH. After conditioning at 23° C. for 24 hours, the barrel was opened and extruded using an extrusion device. To this end, a nozzle with an internal diameter opening of 3 mm was screwed onto the barrel thread. The force required to extrude the composition at an extrusion speed of 60 mm / min was determined using an extrusion device (Zwick / Roell Z005). The values ​​given are the average values ​​of the forces measured after extrusion distances of 22 mm, 24 mm, 26 mm, and 28 mm. The measurement was stopped after an extrusion distance of 30 mm.

[0088] Mechanical property values ​​such as tensile strength: The tensile strength and elongation at break were determined in accordance with DIN EN ISO 527 (tensile speed: 200 mm / min) on films with a layer thickness of 2 mm after curing for 7 days (d) at 23° C. (room temperature “RT”) and 50% relative humidity and after curing for 300 h at 90° C.

[0089] Preparation of polyurethane prepolymer PU-1

[0090] Place Desmodur 44C in a 70°C oven for 2 hours. Place the glass reactor on an electric heating mantle. Under nitrogen, add 300g of 330N and 88g of plasticizer DOA, and raise the temperature to 50°C. Add 50g of Desmodur 44C at a molar ratio of NCO to OH of 2.1:1. After stirring for 5 minutes, add 0.04g of Dabco 33LV catalyst and continue heating to 80°C. Start the timer and measure the NCO content after 1 hour. Stop the reaction when the measured value approaches the set value.

[0091] Preparation of polyurethane prepolymer PU-2

[0092] Place a glass reactor on an electric heating mantle. Under nitrogen, add 39g of Desmodur T80, 325g of JH-240, 130g of GY-4000, and the plasticizer DOA. Raise the temperature to 50°C. After stirring for 5 minutes, add 0.04g of Dabco 33LV catalyst. Continue heating to 80°C. Start the timer and measure the NCO content after 1 hour. Stop the reaction when the measured value approaches the set value.

[0093] Preparation of components of polyurethane prepolymer PU-3

[0094] Place a glass reactor on an electric heating mantle. Under nitrogen, add 69g of Desmodur I, 360g of JH-240, 135g of GY-4000, and the plasticizer DOA. Raise the temperature to 50°C. After stirring for 5 minutes, add 0.06g of DBTDL catalyst. Continue heating to 80°C. Start the timer and measure the NCO content after 1 hour. Stop the reaction when the measured value approaches the set value.

[0095] Preparation of sealant:

[0096] The polyurethane prepolymer, water-absorbing stabilizer, coupling agent, and light stabilizer were added to a planetary stirred tank and stirred thoroughly. Filler and carbon black were then added and stirred thoroughly under vacuum. The vacuum was released with dry nitrogen, and the catalyst was added. The mixture was then vacuumed and stirred thoroughly. The mixture was then discharged and filled into a sealed container for later use. The compositions of the compositions are shown in Table 1 below, where % refers to weight percentage.

[0097] Performance test results

[0098] The prepared composition was tested for various properties according to the test methods described above. The measured properties are listed in Table 2 below.

[0099] Table 1. Composition of the composition

[0100]

[0101] Table 2. Performance test of each composition

[0102]

Claims

1. A polyurethane composition comprising, based on the total weight of the composition: A) 20-50 wt. %, preferably 25-40 wt. % of a polyurethane prepolymer PU, which is a reaction product or a mixture of reaction products of a polyether polyol and at least two aromatic polyisocyanates, wherein the polyether polyol comprises a polyether diol and a polyether triol and the weight ratio of the polyether triol to the polyether diol is in the range of 4:1 to 13:1; and B) 12.5% ​​to 17.5%, preferably 13% to 16.5%, of carbon black.

2. The polyurethane composition according to claim 1, It is characterized in that The aromatic polyisocyanate is a diisocyanate, preferably selected from meta- and para-xylylene diisocyanate (meta- and para-XDI), meta- and para-tetramethyl-1,3-xylylene diisocyanate, meta- and para-tetramethyl-1,4-xylylene diisocyanate, bis-(1-isocyanato-1-methylethyl)-naphthalene, 2,4- and 2,6-toluene diisocyanate (TDI), 4.4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI), 1,3- and 1,4-phenylene diisocyanate, 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, naphthalene-1,5-diisocyanate (NDI), 3,3'-dimethyl-4,4'-diisocyanatobiphenyl (TODI) and mixtures and oligomers thereof; Particularly preferred aromatic polyisocyanates are 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI) and 2,4- and 2,6-toluene diisocyanate (TDI).

3. A polyurethane composition according to any one of the preceding claims, It is characterized in that The polyether diols and polyether triols are selected from polyoxyethylene diols or triols, polyoxypropylene diols or triols, and polyoxypropylene polyoxyethylene diols or triols.

4. A polyurethane composition according to any one of the preceding claims, It is characterized in that The polyurethane prepolymer PU is a mixture of reaction products formed by respectively reacting polyether triol and / or diol with one of two aromatic polyisocyanates, preferably a mixture of reaction products of polyether triol and MDI and reaction products of polyether triol and polyether diol with TDI.

5. A polyurethane composition according to any one of the preceding claims, It is characterized in that The residual free NCO content of the polyurethane prepolymer PU is from 1.0 to 2.5% by weight.

6. A polyurethane composition according to any one of the preceding claims, It is characterized in that The composition comprises a total of 10-70 wt %, preferably 20-60 wt %, more preferably 35-55 wt % of fillers including carbon black.

7. A polyurethane adhesive composition according to any one of the preceding claims, It is characterized in that The composition further comprises a combination of a photocurable material selected from unsaturated acrylic compounds (preferably polyester acrylates) and a hindered amine light stabilizer.

8. A polyurethane adhesive composition according to any one of the preceding claims, It is characterized in that The molecular weight of the polyether diol is in the range of 3000-5000 g / mol, while the molecular weight of the polyether triol is in the range of 4000-6000 g / mol.

9. A polyurethane adhesive composition according to any one of the preceding claims, It is characterized in that The composition comprises at least one other ingredient selected from the group consisting of a crosslinking agent, a plasticizer, a solvent, a catalyst, a tackifier, a drying agent, other stabilizers, a pigment and a rheology aid.

10. A polyurethane adhesive composition according to any one of the preceding claims, It is characterized in that The composition contains less than 1% by weight, preferably 0% by weight, of polyaldimine, based on the total weight of the composition.

11. A cured composition obtained from the composition according to any one of claims 1 to 10 after curing.

12. Methods of bonding or sealing substrates, include: a) applying the composition according to any one of claims 1 to 10 to a first substrate; b) providing a second substrate, to which a composition according to any one of claims 1 to 10 is optionally applied; c) contacting the first and second substrates with each other; The first substrate and the second substrate are made of the same or different materials.

13. The method according to claim 12, It is characterized in that The first substrate and the second substrate are selected from glass, ceramics, concrete, mortar, metal profiles, wood and plastics, the same or different.

14. The method according to claim 12, It is characterized in that For bonding or sealing vehicles and their parts, preferably automobiles and their parts.

15. A product obtained by the method according to any one of claims 12 to 14.

16. Use of 12.5% ​​to 17.5% of carbon black, based on the total weight of the composition, in a polyurethane composition for reducing foaming during curing and increasing matte, wherein the polyurethane composition is as claimed in any one of claims 1 to 10.