EP4284851A1

EP4284851A1 - Silane-terminated polymers

Info

Publication number: EP4284851A1
Application number: EP22703327.1A
Authority: EP
Inventors: Stefan Huber; Thomas ZUBER; Fritz Burkhardt; Claude Lerf
Original assignee: Merz and Benteli Ag; Merz and Bentili AG
Current assignee: Merz and Benteli Ag; Merz and Bentili AG
Priority date: 2021-01-30
Filing date: 2022-01-28
Publication date: 2023-12-06
Also published as: CN116829613A; WO2022162106A1; JP2024504197A; US20240110006A1

Abstract

The present invention relates to a process for preparing a storage-stable silane-terminated polymer of formula (I) or (II) where D is a linear or branched hydrocarbon group having 1 to 20 hydrocarbon atoms and may optionally be interrupted by heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur, A is a polymer backbone selected from the group consisting of a polycarbonate, a polyester, a copolymer comprising a polyester and/or a polycarbonate and a copolymer comprising at least one ester group and/or carbonate group, R1, R1', R2 and R2' independently of one another are each a linear, branched or cyclic hydrocarbon radical having 1 to 10 carbon atoms and may optionally comprise one or more heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, n is 1, 2 or 3, x and y are natural numbers between 1 and 10, G is a linear or branched hydrocarbon group having 1 to 20 hydrocarbon atoms and may optionally be interrupted by heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur, F is a linear, branched or cyclic organic radical containing no isocyanate-reactive groups, m is a natural number greater than 1, E is a reactive group reacting with the isocyanate group and selected from the group consisting of NH2, NHR4 and SH, where R4 a linear, branched or cyclic hydrocarbon radical having 1 to 10 carbon atoms and may optionally comprise one or more heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen.

Description

Silane Terminated Polymers

The present invention relates to a process for the production of silane-terminated polymers which can be used in sealants, adhesives and coating materials and are storage-stable for a long period of time.

The silane-terminated polymers are prepared using known methods. A known method includes, for example, the reaction of polyols, in particular hydroxyl-terminated polyethers, polyurethanes or polyesters, and also hydroxyl-functional polyacrylates, with isocyanatoalkylalkoxysilanes.

Another method provides for a reaction of the above polyols with di- or polyisocyanates, the latter being used in excess, so that isocyanate-functional polymers are produced in this first reaction step, which are then reacted in a second reaction step with alkoxysilanes, which have an alkyl-bonded have isocyanate-reactive group.

The reaction of hydroxyl-functional polymers with isocyanates is carried out in the presence of additional catalysts, since this is the only way to achieve sufficiently high reaction rates for economical preparation of the alkoxysilane-terminated polymers in the corresponding reaction step.

EP 1 995 261 A1 discloses prepolymers containing alkoxysilane groups based on special, low-viscosity polyester polyols which have particularly high strength have, a process for their production and their use as binders for adhesives, primers or coatings. As mentioned in WO2005090428, for example, organotin compounds are used to produce an OH-functional prepolymer and to cap this prepolymer or the polyester polyol in order to accelerate the reaction. Organotin compounds have the disadvantage that they adversely affect the storage stability of the adhesive through transesterification of the polyester backbone. Another problem with tin catalysts is that they are difficult to remove completely after the reaction and are both toxicologically and ecologically unsafe.

WO 2010/136511 discloses silane-functional polyesters which are used as a component in moisture-curing compositions such as adhesives, sealants or coatings based on silane-terminated polymers.

Various processes for preparing silane-terminated polymers are described in the literature. EP 3 744 748 A1 discloses a process for preparing silane-terminated polymers, the urethanization reaction being carried out in the presence of at least one catalyst which is free from organically bound tin. US2019/0031812 discloses a process for preparing silane-terminated polymers. The reaction is carried out in the presence of bismuth neodecanoate. US9321878B2 (D3) discloses processes for preparing silane-terminated polymers in the presence of a tin-free catalyst. EP 2 930 197 discloses a silane terminated adhesive for sealing seams in the navy. The reaction of a polypropylene ether polyol with IPDI and N-(2-triethoxysilylpropyl)-aminosuccinic acid diethyl ester in Described presence of a titanium catalyst. US2017/0240689 discloses a process for producing silane-terminated polymers by reacting a polypropylene glycol with IPDI, isocyanatopropyltriethoxysilane and/or and N-(2-triethoxysilylpropyl)-2-hydroxypropanamide in the presence of bismuth neodecanoate. US2020/0339729 discloses a process for preparing silane-terminated polymers by reacting polypropylene glycol with IPDI, 3-isocyanatopropyltrimethoxysilane and N-(2-triethoxysilylpropyl)aminosuccinic acid diethyl ester.

The use of bismuth catalysts, as described, for example, in EP 1535 940, leads to high catalytic activity and thus to acceleration of the reaction of isocyanatosilanes with the hydroxy-terminated polyol. However, the polyol to be reacted with an isocyanate-functional compound must be dried prior to using a bismuth catalyst to avoid side-reaction of the isocyanate function with the water otherwise present, which impairs the activity of bismuth catalysts. This additional effort is a significant disadvantage of the proposed reaction. In addition, bismuth catalysts cannot be used for the production of hydroxy-terminated polyols, particularly hydroxy-terminated polyesters and hydroxy-terminated polycarbonates.

WO 2020/035154 discloses that a reaction with a bismuth catalyst with a water content of less than 250 ppm is possible without massively restricting the activity. This can limit the drying effort, but it cannot be avoided. In addition, adhesives, sealants and coating materials, which use bismuth catalysts polymers produced contain a significant increase in viscosity during storage and thus poor storage stability.

The object of the present invention is to provide an efficient process for producing a silane-terminated polymer which has excellent storage stability.

The task is solved by the method according to the invention.

Preferred embodiments are subject of the dependent claims.

Surprisingly, it was found that the process according to the invention produces a silane-terminated polymer of the formula (I) or (II) can be produced, which in adhesive, sealing and

Coating materials have an extremely high storage stability having.

With the method according to the invention, the degradation of the polymer backbone, which is selected from the group consisting of a polycarbonate, a polyester, a copolymer containing a polyester and/or a polycarbonate and a polymer containing at least one ester group and/or carbonate group, can be avoided . These polymer backbones can be degraded by the presence of a tin catalyst, which can be avoided by the process according to the invention. The degradation of the polymer chain - or even a break in the polymer chain of the silane-terminated polymer - leads to a significant reduction in the mechanical properties after storage of the composition. In the present invention, it was found that even traces of a tin catalyst used in the production of the starting material can lead to such a degradation. It is therefore very important that the starting materials used are also free of a

are tin catalyst.

According to the invention, the silane-terminated polymer of the formula (I) is obtained by reacting a hydroxy-terminated organic polymer of the formula (III) with an isocyanate of formula (IV)

R ² _3-n (R ¹ O) _n Si-D-NCO (IV), and the silane-terminated polymer of formula (II) prepared by reacting a hydroxy-terminated organic polymer of Formula (III) with a multifunctional isocyanate of formula (V)

F-(N=C=O) _m and subsequent reaction with an alkoxysilane of the formula (VI)

R ^2' _3-n (R ^1' O) _n Si-GE (VI) obtained.

The reaction takes place in the presence of a catalyst. In the compounds of the general formulas I and II

- D for a linear or branched

Hydrocarbon group with 1 to 20

Hydrocarbon atoms which can optionally be interrupted with heteroatoms selected from the group consisting of oxygen, nitrogen and sulphur,

- A stands for a polymer backbone which is selected from the group consisting of a polycarbonate, a polyester, a copolymer containing a polyester and/or a polycarbonate and a polymer containing at least one ester group and/or carbonate group,

- R ₁ , R ₁ ', R ₂ and R ₂ ' independently represent a linear, branched or cyclic

Hydrocarbon radical with 1 to 10 carbon atoms, which optionally has one or more heteroatoms selected from the group consisting of oxygen, may include sulfur and nitrogen,

- n for 1, 2 or 3,

- x and y for natural numbers between 1 and 10,

- F is a linear, branched or cyclic organic radical which contains no isocyanate-reactive groups, i.e. in particular contains neither primary nor secondary amine groups,

- G is a linear or branched hydrocarbon group having 1 to 20 carbon atoms, which can optionally be interrupted with heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur,

- m for a natural number greater than 1,

- E is an isocyanate-reactive reactive group selected from the group consisting of NH ₂ , NHR ⁴ and SH, where R ⁴ is a linear, branched or cyclic hydrocarbon radical having 1 to 10 carbon atoms, optionally containing one or more heteroatoms from the group consisting of oxygen, sulfur and nitrogen.

It is essential to the invention that, in the process according to the invention, both the starting materials used and the reaction itself are free from a tin catalyst. The term tin catalyst is understood to mean any compound containing tin ions and/or organometallic tin compounds which can accelerate the preparation of the starting materials used or the reaction. Typical tin catalysts are, for example, tributyltin, dibutyltin oxide, dioctyltin oxide, dibutyltin dilaurate, dioctyltin dilaurate, and fatty acid salts of tin such as tin(II) stearates or tin(II) laurates. It was found that not only in the reaction itself, ie in the reaction of the hydroxy-terminated organic polymer of the formula (III) and the isocyanate of the formula (IV), or in the reaction of the hydroxy-terminated organic polymer of the formula (III) and the multifunctional Isocyanate of the formula (V) and the subsequent reaction with the alkoxysilane of the formula (VI) no tin catalysts may be used, but in particular also the starting materials, ie the hydroxy-terminated organic polymer of the formula (III), the isocyanate of the formula (IV), the multifunctional isocyanate of the formula (V) and the alkoxysilane of the formula (VI) must be free of tin catalysts in order to obtain a storage-stable sealant.

Tin catalysts are widely used in the preparation of hydroxy-terminated polyesters and polycarbonates, ie, a hydroxy-terminated organic polymer of formula (III) having a polyester or a polycarbonate backbone. At least traces of these remain as active catalysts in the prepolymer, which is then used as starting material for the production of silane-terminated polymers. In the sealants, adhesives or coating materials produced from the polymers, the tin catalysts lead to degradation of the polymer chain of the silane-terminated polymer and thus to a significant reduction in the mechanical properties after storage of the mass, in particular in a significant reduction in the Shore A hardness and /or the tensile strength. The adhesive, sealing and coating compositions in which the silane-terminated polymers according to the invention are used are stable on storage for several months. No impairment of the mechanical properties is observed, especially with Storage of the adhesive, sealing or coating masses at higher temperatures such as 50°C.

Preferably, the present process relates to the preparation of a silane-terminated polymer of formula (I) by reacting a hydroxy-terminated organic polymer of formula (III) with an isocyanate of formula (IV)

R ² _3-n (R ¹ O) _n Si-D-NCO (IV), since this reaction comprises only one reaction step and is therefore cheaper.

In one embodiment, the silane-terminated polymer relates to a linear polymer of general formula IA where R ₁ , R ₂ , D and n have the same definition as above. Linear silane-terminated polymers are used with particular preference for sealants and coating materials for which greater elasticity is required, such as for joint compounds, elastic adhesives, surface seals or in the marine sector, for example for pointing teak.

In a second embodiment relates to the silane-terminated

Polymer a branched polymer of the general formula IB

where R ₁ , R ₂ , D, n, x and y have the same definition as above. The silane-terminated polymer of the formula IB is preferably essentially free of free OH groups, ie y and x are essentially identical and the difference between yx is therefore approximately 0. Branched silane-terminated polymers of the formula IB are particularly preferred for adhesive, sealant and coating compounds that require a higher Shore A hardness and a higher crosslinking density, such as high-modulus adhesives, surface seals or floor coatings.

Preferably, no bismuth and/or zinc catalysts are used in the reaction either, since these catalysts have poor hydrolytic stability, can lead to side reactions and/or are complicated to handle. In particular, bismuth and/or zinc catalysts cannot be used for the production of the hydroxy-terminated polymer, especially for polyesters and polycarbonates. According to the present invention, however, the same catalyst is preferably used in the reaction as in the preparation of the hydroxy-terminated polymer, which is advantageous for ecological and economic reasons. In addition, adhesives, sealants and coating materials which contain polymers produced using bismuth catalysts exhibit a significant increase in viscosity during storage and therefore poor storage stability. At least one catalyst is preferably used for the process according to the invention, which can be used both for the production of the hydroxy-terminated prepolymer and for the reaction of the isocyanatosilane with the hydroxy-terminated polymer and which does not adversely affect the storage stability of the adhesives, sealants and coating materials produced therefrom. The at least one catalyst is particularly preferably a titanium-containing organometallic compound, which can optionally also be combined with other catalysts such as lithium compounds. This further catalyst can optionally also only be added during the reaction of the hydroxy-terminated prepolymer and the isocyanatosilane. These catalysts do not adversely affect the storage stability of the adhesives, sealants and coating materials produced from them and do not have to be removed from the polymer in a complicated manner.

The titanium-containing organometallic compounds which are preferably used as catalysts in the process according to the invention preferably contain ligands which are selected from

- an alkoxy group such as isobutoxy, n-butoxy, isopropoxy, ethoxy and 2-ethylhexoxy;

- a sulfonate group, such as aromatic sulfonates, the aromatics of which are substituted with an alkyl group and

- a carboxylate group, such as

carboxylates of fatty acids;

- a ketoester group, such as

acetoacetic ester derivatives; and

- a dialkyl phosphate group, where all ligands can be identical or different from each other.

As an alternative or in addition, the titanium-containing organometallic compounds particularly preferably have at least one polydentate ligand as ligand, which makes chelation possible. The multidentate ligand is preferably a bidentate ligand.

The titanium-containing organometallic compounds are particularly preferably selected from the group consisting of bis(ethylacetoacetato)diisobutoxytitanium (IV), bis(ethylacetoacetato)diisopropoxytitanium (IV), bis(acetylacetonato)diisopropoxytitanium (IV) , bis(acetylacetonato)diisobutoxytitanium (IV), tris(oxyethyl)amineisopropoxytitanium (IV), bis[tris(oxyethyl)amine]diisopropoxytitanium (IV), bis(2-ethylhexane-1,3 -dioxy)-titanium (IV), tris[2-((2-aminoethyl)amino)ethoxy]-ethoxy-titanium (IV), bis(neopentyl(diallyl)oxy-diethoxytitanium (IV), titanium( IV) tetrabutanolate, tetra-(2-ethylhexyloxy)titanate, tetra-(isopropoxy)titanate, tetrabutyl titanate, tetraisopropyl titanate, tetra-2-ethylhexyltitanate and titanium acetylacetonate and polybutyltitanate are particularly preferred because of the good price-performance ratio tetrabutyl titanate and tetraisopropyl titanate.

The hydroxy-terminated organic polymer of formula (III) preferably has a polymer backbone A selected from the group consisting of polyesters, polycarbonates and copolymers containing a polyester and/or a polycarbonate. The term “copolymers containing a polyester and/or a polycarbonate” is understood to mean polymers composed of two or more monomer units. In addition to alternating copolymers and graft copolymers, the term also includes, in particular, block polymers which consist of longer sequences or blocks of each monomer and can be linked to one another via linker connections. Preferred combinations of blocks are

- Polyesters and polycarbonates

- Various polyesters

- Polyester and polyether as well

- Polycarbonates and polyethers.

The expression “copolymer containing a polyester and/or a polycarbonate” stands for a copolymer which contains at least one block made from a polyester and/or a polycarbonate and contains further blocks. In such a copolymer the polyester moiety or the polycarbonate moiety is at least 10% by weight, preferably at least 25% by weight and most preferably at least 50% by weight. Basically, the higher the polyester and/or polycarbonate content, the greater the risk of degradation of the polymer backbone.

Examples of this are the preferred combinations mentioned above. Preferred linker compounds are urethane, ester and amide compounds, most preferably urethane compounds.

The polymer backbone A contains one or more ester and/or carbonate groups. They preferably contain more than 2, more preferably more than 10 ester and/or carbonate groups. Within the present invention, the definition of the polymer backbone A also includes polymers that are extended with a linker compound, such as polymers that are terminally extended with a diol, polymers that have been dimerized or oligomerized by means of a diisocyanate or dicarboxylic acid dichloride and copolymers, which have been copolymerized using diisocyanates or dicarboxylic acid dichlorides. Such polymers can have 1, 2 or preferably 3 and more ester and/or carbonate groups within the polymer backbone. The higher the number of ester and/or carbonate groups, the higher the risk of polymer backbone degradation with the corresponding stability consequences for the final end product.

The expression hydroxy-terminated stands for polymers which carry free hydroxy groups at the end of the molecule, y is a natural number from 1 to 10. In a preferred embodiment, y=1 and then corresponds to an α,ω-dihydroxy-terminated organic polymer, ie a polymer with two terminals OH groups. If y is greater than 1, the hydroxy-terminated polyol has more than two terminal OH groups, ie it is a polyol whose OH groups are designed to react with the isocyanate of formula IV. In the case of branched, hydroxy-terminated polymers, the OH groups are preferably not attached directly to the polymer backbone, but rather to the end of side chains of the polymer backbone. They can be obtained, for example, by reactions with polyols or polycarboxylic acids. Both linear and branched hydroxy-terminated organic polymers are known to those skilled in the art and are also commercially available. Polycarbonates can be obtained, for example, by reacting diols such as propylene glycol, 1,4-butanediol or 1,6-hexanediol, diethylene glycol, triethylene glycol or tetraethylene glycol or mixtures of two or more thereof with diaryl carbonates, for example diphenyl carbonate or phosgene. However, the term polyester also includes polyester polyols which are formed by reacting low molecular weight alcohols or mixtures thereof, in particular ethylene glycol, diethylene glycol, propanediol, dipropylene glycol, neopentyl glycol, hexanediol, butanediol, pentanediol, hexanediol, propylene glycol, glycerol or trimethylolpropane with caprolactone and their terminal Hydroxy groups then represent the hydroxy groups of the organic polymer of formula III. Most preferably, the polymer backbone contains a branched diol component. Such a branched diol component of the low molecular weight alcohol used to prepare the polyester or polycarbonate is particularly preferably a branched diol selected from the group consisting of 3-methyl-1,5-pentanediol, 2-methyl- 1,3-propanediol, 3-ethylpentane-1,5-diol, 1,2-propanediol and 2,4-diethyl-1,5-pentanediol, since the polymers produced from them have particularly good processability and stability.

A is particularly preferably a polycarbonate selected from the group consisting of polypropylene carbonate, polycyclohexene carbonate, poly(4,4'-isopropylidene diphenyl carbonate), poly(4,4'-diphenyl-1,1'-cyclohexane carbonate) and poly(propylene). -cyclohexene) carbonate or a polyester selected from the group consisting of poly(ethylene terephthalate) (PET), poly(ethylene naphthalate), poly(propylene terephthalate), polybutylene terephthalate (PBT), Polycyclohexylenedimethylene-2,5-furandicarboxylate (PCF), polybutylene adipate-co-terephthalate (PBAT), polybutylene sebacate-co-terephthalate (PBSeT), polybutylene succinate-co-terephthalate (PBST), poly-butylene-2,5-furandicarboxylate-cosuccinate (PBSF), poly-butylene -2,5-furandicarboxylate-coadipate (PBAF), poly-butylene-2,5-furandicarboxylate-coazelate (PBAzF), poly-butylene-2,5-furandicarboxylate-cosebacate (PBSeF), poly-butylene-2,5- furandicarboxylate cobrassylate (PBBrF), polybutylene succinate (PBS), polybutylene adipate (PBA), polybutylene succinate coadipate (PBSA), polybutylene succinate cosebacate (PBSSe), polybutylene sebacate (PBSe) or a polyester polyol of at least one hydroxyl-containing component selected from, for example, 1 ,2-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 3-ethylpentane-1,5-diol, 2,4-diethyl-1,5-pentanediol, neopentyl glycol and 1,1,1-trimethylolpropane and mixtures thereof, and at least one carboxyl-containing component selected from aliphatic S acids with two carboxyl groups such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, brassylic acid and dimer acids, or dialkyl esters of acids with two carboxyl groups such as dimethyl ester, diethyl ester, dipropyl ester and dibutyl ester or carboxylic acid chlorides such as acrylic or methyl acid chloride; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid or dialkyl ester acids having two carboxyl groups such as dimethyl ester, diethyl ester, dipropyl ester and dibutyl ester; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid, or dialkyl esters of dicarboxylic acids such as dimethyl ester, diethyl ester, dipropyl ester and dibutyl ester, and the like. Of these examples, adipic acid, Azelaic acid, sebacic acid, terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid are preferably used. Also possible is the use of cyclic carboxylic anhydrides such as phthalic anhydride, maleic anhydride, succinic anhydride or with a side group such as 3-methylglutaric anhydride. Aliphatic dicarboxylic acids or their esters with side groups can also be used, such as 2,4-diethylglutaric acid, 2,4-methylglutaric acid, 3-methylglutaric acid, methylmalonic acid. Polyester polyols and polycarbonates are particularly preferred which contain >10 mol % of a branched diol as the hydroxyl group-containing component, such as 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 3-ethyl-pentane-1, 5-diol, 1,2-propanediol, 2,4-diethyl-1,5-pentanediol, as these have proven to be particularly stable. The fraction of the branched diol is particularly preferably >50 mol % of the diol used. Aliphatic dicarboxylic acids are used as the preferred dicarboxylic acid. The diols as well as the dicarboxylic acids can be based on petroleum or have been produced from renewable raw materials.

Preferably, the hydroxy-terminated organic polymer is liquid at room temperature. This means a viscosity at 20° C. of 1 to 10 ⁶ mPa*s. This viscosity is optimal for handling the composition according to the invention, in particular in the production of sealant preparations. This applies in particular to hydroxy-terminated polymers which have a homopolymer of a polycarbonate or a homopolymer of a polyester as the polymer backbone. In general, the polyesters according to the invention have a relatively low viscosity and are inexpensive. Hence they are for some uses more suitable than the polycarbonates according to the invention.

The hydroxy-terminated organic polymer preferably has an average molecular weight of 1000-20000 g/mol, in particular 2000-12000 g/mol, since the handling of these polymers is optimal. As used herein, "molecular weight" means the molar mass (in grams per mole) of a molecule. The “average molecular weight” is the number-average molecular weight Mn of a polydisperse mixture of oligomeric or polymeric molecules, which is usually determined by titrating the acid number and OH number. The OH number (hydroxyl number) is a measure of the hydroxyl group content in polymers and is a value known to those skilled in the art. The acid number is a measure of the content of acid groups in polymers and is a value known to those skilled in the art.

The hydroxy-terminated organic polymers of the formula (III) used according to the invention can be commercially available compounds which, for better handling, can optionally be diluted with a plasticizer or solvent. However, it is important that they are produced tin-free, since even traces of a tin catalyst in the hydroxy-terminated organic polymer of the formula (III) adversely affect the storage stability of the silane-terminated polymer and in particular of the adhesive, sealing and coating compositions produced therefrom. The same catalyst is preferably used in the production of the hydroxy-terminated organic polymer and the silane-terminated polymer, so that it does not have to be removed from the hydroxy-terminated organic polymer, which makes process engineering sense and is more ecological. The catalyst is preferably used in amounts of 0.5 to 500 ppm of the hydroxy-terminated organic polymer of the formula (III).

The isocyanates of the formula (IV) used according to the invention

R ² _3-n (R ¹ O) _n Si-D-NCO (IV) are commercially available products or can be prepared by processes customary in silicon chemistry. Ri and R2 are independently a linear, branched or cyclic hydrocarbon radical having 1 to 10 carbon atoms, which can optionally include one or more heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, n can have the value 1, 2 or 3, the values 2 or 3 being preferred, since the silane-terminated polymers produced therefrom have a particularly balanced reactivity.

Preferably, R ¹ and R ² are independently alkyl, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, n-heptyl, octyl, n-octyl, isooctyl, 2,2,4-trimethylpentyl, n-nonyl, decyl, n-decyl , dodecyl radicals or an n-dodecyl radical. However, they can also represent alkenyl radicals, such as a vinyl or an allyl radical; cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl and methylcyclohexyl; aryl radicals such as phenyl and naphthyl; alkaryl groups such as o-, m-, p-tolyl groups, xylyl groups and ethylphenyl groups; Aralkyl radicals, such as the benzyl radical, the α- and the β-phenylethyl radical. examples for substituted radicals R ¹ are alkoxyalkyl radicals such as ethoxy and methoxyethyl radicals.

The radicals R ¹ and R ² are preferably each independently a hydrocarbon radical having 1 to 6 carbon atoms, particularly preferably an alkyl radical having 1 to 4 carbon atoms, in particular the methyl or ethyl radical.

D represents a linear or branched hydrocarbon group having 1 to 20 carbon atoms, which can optionally be interrupted with heteroatoms selected from the group consisting of oxygen, nitrogen and sulfur. Preferably D is selected from the group consisting of methylene, ethylene, propylene, butylene, methylene oxide, ethylene oxide and propylene oxide and more preferably propylene or methylene as this results in polymers with a particularly balanced reactivity.

Examples of isocyanates of the formula (IV) are isocyanatomethyldimethylmethoxysilane, isocyanatopropyldimethylmethoxysilane, isocyanatomethylmethyldimethoxysilane, isocyanatopropylmethyldimethoxysilane, isocyanatomethyltrimethoxysilane, isocyanatomethyltriethoxysilane and isocyanatopropyltrimethoxysilane , wherein isocyanato-methyl-methyldimethoxysilane, isocyanato-propyl-methyldimethoxysilane, isocyanato-propyl-trimethoxysilane, isocyanato-propyl-triethoxysilane and isocyanato-methyl-triethoxysilane are preferred.

The process according to the invention for preparing the silane-terminated polymer of the formula (II) is carried out by reacting a hydroxy-terminated organic polymer of formula (III) with a multifunctional isocyanate of formula (V)

F-(N=C=O) _m and subsequent reaction with an alkoxysilane of the formula

(VI)

R ^2' _3-n (R ^1' O) _n Si-GE (VI), both the starting materials used and the reaction also being free of a tin catalyst here.

Particularly suitable polyfunctional isocyanates of the formula (V) are isocyanates having two or more, preferably 2 to 10, isocyanate groups in the molecule. Suitable for this purpose are the known aliphatic, cycloaliphatic, aromatic, oligomeric and polymeric multifunctional isocyanates, which contain no isocyanate-reactive groups, ie in particular have no free primary and/or secondary amino groups. A representative of the aliphatic multifunctional isocyanates is, for example, hexamethylene diisocyanate (HDI); a representative of the cycloaliphatic multifunctional isocyanates is z. B. 1-Isocyanato-3-(isocyanatomethyl)-3,5,5-trimethylcyclohexane. The following may be mentioned as representatives of the aromatic multifunctional isocyanates: 2,4- and 2,6-diisocyanatotoluene and the corresponding technical isomer mixture (TDI); Diphenylmethane diisocyanates, such as diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, diphenylmethane-2,2'-diisocyanate and the corresponding ones technical isomer mixtures (MDI). Mention should also be made of naphthalene-1,5-diisocyanate (NDI) and 4,4',4"-triisocyanatotriphenylmethane.

Alkoxysilanes of the formula (VI) are preferably selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-aminopropyldimethoxymethylsilane, 3-amino-2-methylpropyltrimethoxysilane, 4-aminobutyltrimethoxysilane, 4-aminobutyldimethoxymethylsilane, 4-amino-3- methylbutyltrimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, 4-amino-3,3-dimethylbutyldimethoxymethylsilane, 2-aminoethyltrimethoxysilane, 2-aminoethyldimethoxymethylsilane, aminomethyltrimethoxysilane, aminomethyldimethoxymethylsilane, aminomethylmethoxydimethylsilane and 7-amino-4- oxaheptyldimethoxymethylsilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-[2 -(2-aminoethylamino)ethylamino]propyltrimethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyltriethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propylmethyldimethoxysilane,

[3-(1-Piperazinyl)propyl]triethoxysilane, [3-(1-Piperazinyl)propyl]trimethoxysilane, [3-(1-Piperazinyl)propyl]methyldimethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, N- (n-Butyl)-3-aminopropylmethyldimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane, N-ethylaminoisobutyltrimethoxysilane, N-ethylaminoisobutylmethyldimethoxysilane, N-cyclohexyl-3-aminopropyltriethoxysilane, N-cyclohexyl-3 - aminopropyltrimethoxysilane, N- cyclohexylaminomethyltriethoxysilane, N- cyclohexylaminomethyltrimethoxysilane, N- cyclohexylaminomethyldimethoxymethylsilane, bis(trimethoxysilylpropyl)amine, 3-

Mercaptopropyltrimethoxysilane, 3-

Mercaptopropyltriethoxysilane, 3-

mercaptopropylmethyldimethoxysilane.

In order to accelerate the urethane or urea bond, a further catalyst which does not adversely affect the storage stability of the products and the adhesives, sealants or coating materials produced from them can optionally be used.

This catalyst preferably consists of

- Alkali metal carboxylates such as

lithium neodecanoate, lithium ethylhexanoate, lithium laurate, lithium stearate, potassium neodecanoate, potassium ethylhexanoate, or potassium laurate;

- Alkaline earth metal carboxylates such as

Calcium Trimethylhexanoate, Calcium Neodecanoate,

calcium laurate, strontium ethylhexanoate or

strontium laurate;

- Carboxylates of the subgroup elements such as

Cobalt ethyl hexanoate, cobalt stearate, cobalt laurate, cobalt neodecanoate, manganese ethyl hexanoate,

manganese stearates, manganese laurates, iron stearates,

Iron ethylhexanoate, iron laurate, copper stearate, copper laurate, copper neodecanoate, copper ethylhexanoate,

- carboxylates from the boron group such as indium, aluminum salts,

- Salts from the carbon group such as

lead salts,

- Salts from the nitrogen group such as phosphorus salts and phosphorus esters or antimony salts;

- Tertiary amines such as tributylamine, 1,4-

diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-

7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, N,N-bis(N,N-dimethyl-2-aminoethyl)methylamine, N,N-

dimethylcyclohexylamine, N,N-dimethylphenylamine or

ethylmorpholinine;

- ionic liquids such as ionic

ammonium, imidazolium, phosphonium, pyridinium, pyrrolidinium, or sulfonium based liquids;

- Short-chain organic acids with 1 to 10 carbon atoms such as acetic acid and

- Inorganic acids such as phosphoric acid and its half esters, such as butyl phosphate, dibutyl phosphate and propyl phosphate.

These other catalysts can be used individually or in combination.

The other catalysts are very particularly preferably selected from the group consisting of lithium neodecanoate, lithium ethyl hexanoate, lithium laurate, lithium stearate, manganese ethyl hexanoate, manganese neodecanoate, manganese laurate, manganese stearate, cobalt ethyl hexanoate, cobalt laurate, cobalt stearate and cobalt neodecanoate. The further catalyst is particularly preferably combined with a titanium-containing organometallic compound.

The catalyst is preferably added in an amount of 1 to 1000 ppm, particularly preferably 5 to 500 ppm and very particularly preferably 5 to 200 ppm. The linear silane-terminated polymers are particularly preferably selected from the group consisting of whereby

A represents a polymer backbone as defined above. The reaction is preferably carried out at temperatures between 50° C. and 150° C., particularly preferably at 60° C. to 120° C. and preferably at normal pressure.

The crosslinkable compositions produced according to the invention are excellently suited as Sealing compounds for joints, including vertical joints, and similar empty spaces, e.g. in buildings, land, water and air vehicles, or as adhesives or cementing compounds, e.g. in window construction or in the manufacture of showcases, and for the production of protective coatings or rubber-elastic moldings as well as for the insulation of electrical or electronic devices. The compositions according to the invention are particularly suitable as sealing compounds for joints with possible high absorption of movement. The adhesives, sealants and coating materials according to the invention have significantly better weathering stability than standard products. As a result of the significantly better weathering stability, the coating materials of the invention are particularly suitable for roof waterproofing and surface waterproofing or for coating other surfaces which are exposed to severe weathering.

The usual water content of the air is sufficient for the crosslinking of the composition according to the invention. The crosslinking can be carried out at room temperature or, if desired, also at higher or lower temperatures, for example at -5 to 10°C or at 30 to 50°C. The crosslinking is preferably carried out under atmospheric pressure.

The silane-terminated polymers according to the invention can also be formulated as a 2-component system. In addition to additives, the second component also contains water, which greatly accelerates deep curing after mixing with the first component. Corresponding 2-component systems are known to the person skilled in the art and are described, for example, in EP2009063 or EP2535376, the content of which is incorporated by reference becomes.

The preparations according to the invention can also contain other auxiliaries and additives, which likewise must not contain any tin catalysts. These auxiliaries and additives include, for example, other silane-terminated polymers, plasticizers, stabilizers, antioxidants, fillers, reactive diluents, drying agents, adhesion promoters and UV stabilizers, rheological auxiliaries, color pigments or color pastes and/or possibly also to a small extent solvents. Such auxiliaries and additives are known to those skilled in the art.

examples

Example 1 (according to the invention)

234 g of polyester polyol P-4010 (Kuraray Co, Ltd) synthesized using an organotitanate catalyst (titanium (IV) isopropoxide) and having a hydroxyl value of 28.7 mg KOH/g was heated to 90°C with stirring heated. 22.4 g of (trimethoxysilyl)propyl isocyanate were added and stirred at 90°C. After 90 minutes, free isocyanate was no longer detected by FT-IR. The obtained trimethoxysilane-terminated polyester was used for the formulation of the adhesive.

Example 2 (according to the invention)

229 g of polyester polyol SS 4080 (Songstar), which was synthesized with an organotitanate catalyst and has a hydroxyl number of 29.4 mg KOH/g, was heated to 90° C. with stirring. 22.4 g (trimethoxysilyl)propyl isocyanate were added and stirred at 90°C. After 90 minutes, free isocyanate was no longer detected by FT-IR. The obtained trimethoxysilane-terminated polyester was used to formulate the adhesive.

Example 3 (not according to the invention)

240 g of polyester polyol SS 4080S (Songstar), which was synthesized with an organotin catalyst and has a hydroxyl number of 28.0 mg KOH/g, was heated to 90° C. with stirring. 22.4 g of (trimethoxysilyl)propyl isocyanate were added and stirred at 90°C. After 600 minutes, free isocyanate was no longer detected by means of FT-IR. The obtained trimethoxysilane-terminated polyester was used to formulate the adhesive.

Example 4 (not according to the invention)

229 g of polyester polyol SS 4080 (Songstar), which was synthesized with an organotitanate catalyst and has a hydroxyl number of 29.4 mg KOH/g, was heated to 90° C. with stirring. 63 mg of dibutyltin dilaurate as a tin catalyst and 22.4 g of (trimethoxysilyl)propyl isocyanate were added and the mixture was stirred at 90.degree. After 90 minutes, free isocyanate was no longer detected by FT-IR. The obtained trimethoxysilane-terminated polyester was used to formulate the adhesive.

Example 5 (not according to the invention)

240g of polyester polyol SS 4080S (Songstar) synthesized with an organotin catalyst and having a hydroxyl number of 28.0 mg KOH/g was heated to 90°C with stirring. 75mg dibutyltin dilaurate as a tin catalyst and 22.4g of (trimethoxysilyl)propyl isocyanate were added and stirred at 90°C. After 90 minutes, free isocyanate was no longer detected by FT-IR. The obtained trimethoxysilane-terminated polyester was used to formulate the adhesive. The results are shown in Figure 1 (Table 1).

The final adhesive is only stable if no tin catalysts are present during the production of the hydroxy-terminated polyester, the reaction with the isocyanate silane and the formulation as an adhesive, sealing or coating material. Otherwise, the Shore A hardness (measured according to DIN 53505) and the tensile strength (measured according to DIN 53504) decrease significantly after the sealant has been stored in a cartridge at room temperature for 4 to 8 weeks. At higher storage temperatures, the mechanical properties decrease even more quickly in the presence of a tin catalyst.

The tables below show the stability of the compositions after 8 and after 32 weeks:

nc stands for normal climate, 23°C, 50% relative humidity, * means no crosslinking within the given range

curing time.

Claims

patent claims

1. Process for preparing a silane-terminated

Polymer of formula (I) or (II) by reaction of a hydroxy-terminated organic

polymer of formula (III) a) with an isocyanate of the formula (IV)

R ² _3-n (R ¹ O) _n Si-D-NCO (IV), or b) with a multifunctional isocyanate of formula (V)

F-(N=C=O) _m (V) and subsequent reaction with an alkoxysilane Formula (VI)

R ^2' _3-n (R ^1' O) _n Si-GE (VI) in the presence of a catalyst, wherein

D represents a linear or branched hydrocarbon group with 1 to 20 carbon atoms, which can optionally be interrupted with heteroatoms selected from the group consisting of oxygen, nitrogen and sulphur,

A stands for a polymer backbone which is selected from the group consisting of a polycarbonate, a polyester, a copolymer containing a polyester and/or a polycarbonate and a polymer containing at least one ester group and/or carbonate group,

R ₁ , R ₁ ', R ₂ and R ₂ ' independently represent a linear, branched or cyclic hydrocarbon radical having 1 to 10 carbon atoms, which optionally may comprise one or more heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, n is equal to 1, 2 or 3, x and y are natural numbers between 1 and 10,

G represents a linear or branched hydrocarbon group with 1 to 20 carbon atoms, which can optionally be interrupted with heteroatoms selected from the group consisting of oxygen, nitrogen and sulphur,

F is a linear, branched or cyclic organic is a radical that does not contain any groups that are reactive toward isocyanate, m is a natural number greater than 1,

E is an isocyanate-reactive reactive group selected from the group consisting of NH ₂ , NHR ⁴ and SH, where

R ⁴ is a linear, branched or cyclic hydrocarbon radical having 1 to 10 carbon atoms, which can optionally comprise one or more heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, characterized in that both the starting materials used and the reaction are free from one are tin catalysts.

2. The method according to claim 1, characterized in that A is a polymer backbone which is selected from the group consisting of a polycarbonate, a polyester, a copolymer containing a polyester and / or a polycarbonate and at least three ester groups and / or polymer containing carbonate groups, preferably composed of a polycarbonate, a polyester and a copolymer containing a polyester and/or a polycarbonate.

3. The method according to any one of claims 1 or 2, characterized in that the polymer backbone contains a branched diol component, preferably selected from the group consisting of 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol , 3-ethyl pentane-1,5-diol, and 2,4-diethyl-1,5-pentanediol, and more preferably that the branched diol component is selected from the group consisting of 3-methyl-1,5-pentanediol, 2-methyl -1,3-propanediol, 3-ethylpentane-1,5-diol, 1,2-propanediol and 2,4-diethyl-1,5-pentanediol, these having a proportion of more than 10 mol% of a hydroxyl-containing component of the Polyester or polycarbonate constitutes.

4. The method according to any one of the preceding claims, characterized in that the reaction with an isocyanate of the formula (IV)

R ² _3-n (R ¹ O) _n Si-D-NCO (IV).

5. The method according to any one of the preceding claims, characterized in that the silane-terminated polymer is a linear polymer of the general formula (IA) represents.

6. The method according to claim 1 to 4, characterized in that the silane-terminated polymer is a branched polymer of the general formula (IB)

represents, where x and y each correspond to a natural number between 2 and 10.

7. The method according to claim 6, characterized in that the silane-terminated polymer of the formula (IB) is essentially free of free hydroxyl groups.

8. The method according to any one of the preceding claims, characterized in that both the preparation of the starting material and the preparation of the silane-terminated polymer of the general formula (I) or (II) takes place with the same catalyst.

9. The method according to any one of the preceding claims, characterized in that the reaction takes place in the presence of a titanium-containing organometallic compound.

10. The method according to claim 9, characterized in that the titanium-containing organometallic compound is selected from the group consisting of bis (ethylacetoacetato) - diisobutoxy titanium (IV), bis (ethylacetoacetato) - diisopropoxy titanium (IV), bis (acetylacetonato) - diisopropoxy titanium (IV), bis(acetylacetonato)diisobutoxy titanium (IV), tris(oxyethyl)amine isopropoxy titanium (IV), bis[tris(oxyethyl)amine]diisopropoxytitanium (IV), bis( 2-ethylhexane-1,3-dioxy)- Titanium (IV), Tris[2-((2-aminoethyl)amino)ethoxy]-ethoxy-titanium (IV), Bis(neopentyl(diallyl)oxy-diethoxytitanium (IV), Titanium (IV)-tetrabutanolate, Tetra- ( 2- ethylhexyloxy)titanate, tetra-(isopropoxy)titanate,

Tetrabutyl titanate, tetraisopropyl titanate, tetra-2-ethylhexyl titanate and titanium acetylacetonate and polybutyl titanate, particularly preferably tetrabutyl titanate and tetraisopropyl titanate.

11. The method according to any one of the preceding claims, characterized in that the reaction takes place in the presence of a further catalyst, preferably a further catalyst selected from the group consisting of alkali metal carboxylates,

Alkaline earth metal carboxylates, carboxylates of

Subgroup elements, carboxylates from the boron group, lead salts, phosphorus salts, phosphorus esters, antimony salts, tertiary amines, ionic liquids, organic acids having 1 to 10 carbon atoms and inorganic acids.

12. The method according to any one of the preceding claims, characterized in that the catalyst is not removed after the end of the reaction.

13. The method according to any one of the preceding claims, characterized in that the polymer backbone is a polyester.

14. The method according to any one of the preceding claims, characterized in that the isocyanate of the formula (IV) is selected from the group consisting of isocyanato-propyl-trimethoxysilane, isocyanato-propyl-methyldimethoxysilane, isocyanato-propyl-triethoxysilane, isocyanato-methyl-methyldimethoxysilane and isocyanato-methyl-triethoxysilane.

15. A composition containing a silane-terminated polymer according to any one of claims 1 to 14 for use as

Adhesive, sealing or coating material, characterized in that the composition is free from a tin catalyst.