MXPA99011145A - Preparations of hibri lacquer - Google Patents

Abstract

The present invention relates to condensation products of aliphatic-aminosilane polyisocyanate adducts with hydrolysable silanes, a process for their preparation as well as their use in sol-g lacquers.

Description

Field of the Invention The present invention relates to condensation products of aliphatic-aminosilane polyisocyanate adducts with hydrolysable silanes, a process for their preparation as well as their use in sol-gel lacquers. For demanding coatings, for example in the automotive sector, the lacquer industry demands lacquers that have an ideal combination of very good mechanical properties in their properties profile, such as very high hardness and abrasion resistance with high flexibility at the same time , with very good chemical properties, such as resistance to solvents and chemical agents.

BACKGROUND OF THE INVENTION It is known that the pure inorganic coating systems based on siloxanes, which were obtained by reaction of hydrolysable silane groups with water or water-releasing agents, are distinguished by a high resistance to scratching. and resistance to agents REF .: 32229 chemicals. A generally known process for the preparation of such pure inorganic coatings is the sol-gel process, as extensively described by. C. J. Brinker and W. Scherer in "Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing", Academic Press, New York (1990). A major disadvantage of the described inorganic pure coatings is that they are brittle and tend to stress cracking. Therefore, pure inorganic coatings are not suitable for flexible substrates. Therefore, various supplements are known from the literature to combine the described positive properties of pure inorganic coatings with the properties of organic coatings. An overview of so-called inorganic-organic hybrid lacquers is found in J. Mater. Chem. 6 (1996) 511. Concrete proposals for solutions are found in US-A 5378790, US-A-5344712, US-A 5316855, EP-A 565044, EP-A 505737 and DE-A 40 20 316. No lacquer system known by the state of the art satisfactorily fulfills its ex ceptional purpose as demanded by the lacquer industry. Therefore, the purpose of the invention was to prepare the lacquer system which has an improved balance between high hardness, resistance to abrasion as well as resistance to chemical agents on the one hand and, on the other hand, higher flexibility. The reaction products of aminosilanes with polyisocyanates are known (see, for example, "Adhesives Age" 5/1995, page 30 et seq.) Such alkoxysilane-terminated polyurethanes which are hardened with moisture are increasingly used in masses flexible for sealing and adhesives that harden at room temperature (US-A 5700868, US-A 4625012, US-A 4474933, US-A 3979344, DE-A 4234325 and DE-A 2155259). the known citations of the literature describe condensation products of aliphatic-aminosilane polyisocyanate adducts with hydrolysable silanes as well as their use in sol-gel lacquers.Surprisingly, it was now found that the condensation products of aliphatic-aminosilane polyisocyanate adducts with hydrolysable silanes present , in preparations of lacquers so -ge, ance ance ora or in re aa ureza, resistance to abrasion as well as resistance to chemical agents on the one hand and, on the other hand, higher flexibili The polyisocyanato-aminosilane adducts react with the hydrolysable silanes by means of a polycondensation, providing a flexible coating, inorganic-organic hybrid, of high hardness and very good resistance to solvents.

Description of the invention The object of the invention are condensation products of aliphatic-aminosilane polyisocyanate adducts and hydrolysable silanes, which are obtained by reaction of A) 5 to 80% by weight, preferably 20 to 70% by weight of an Al adduct ) a (aliphatic polyisocyanate (s) mixture, having an average NCO functionality of 2.5 to 5.5 and an isocyanate content of 9 to 50% by weight, with A2) at least 0 , 7 equivalents of aminosilane of formula (I) (RO) nY3-nSi -CH2CH2CH2-NHZ (I) in which R represents methyl, ethyl, Y represents methyl, ethyl, Z represents H, alkyl (C? -C? 2), CH2CH2CH2-S i (OR) " Y3-n, and n represents the number 1, 2 or 3, per equivalent of isocyanate A3), possibly other compounds reactive towards isocyanate, with B) 20 to 95% by weight, preferably 30 to 80% by weight of at least one silane of formula (II) QSi (OX) 3 (II) wherein X represents alkyl (C? -C4) and Q represents H, Ci to C8 alkyl, phenyl, methoxy, ethoxy, 3-glycidyloxy-propyl, 3-aminopropyl and methacryloxypropyl or hydrolysates / condensates preparable from these silanes .

The products according to the invention can also be designated hybrid lacquers. Another object of the invention is a process for the preparation of the condensation products according to the invention, characterized in that the condensation products of polyisocyanate aliphatic-aminosilane adducts and hydrolyzable silanes, which are prepared by the reaction of A) 5 to 80% by weight, preferably 20 to 70% by weight of an adduct of Al) a (a mixture of) aliphatic polyisocyanate (s), having an average NCO functionality of 2.5 to 5 , And an isocyanate content of 9 to 50% by weight, with A2) at least 0.7 equivalents of aminosilane of formula (I) (RO) nY3-nSi-CH2CH2CH2-NHZ (I) wherein R represents methyl, ethyl, Y represents methyl, ethyl, represents, to which 1-12, CH2CH2CH2-Si (0R) nY3-n, Y n represents the number 1, 2 or 3, and per equivalent of isocyanate A3) optionally other compounds reactive towards isocyanate, are reacted with B) 20 to 95% by weight, preferably 30 to 80% by weight of at least one silane of formula (II) QSi (OX) 3 (II) wherein X represents (C1-C4) alkyl Q represents H, Ci to Cs alkyl, phenyl, methoxy, ethoxy, 3-glycidyloxy-propyl, 3-aminopropyl and methacryloxypropyl or hydrolysates / condensates preparable from these silanes.

Another object of the invention is the use of the condensation products according to the invention as a lacquer preparation for the recovery of ores, p scis, large or, marble, metal, wood, leather and textile objects. The (the mixture of) aliphatic polyisocyanate (s) usable according to the invention has an average NCO functionality of from 2.5 to 5.5, preferably from 2.8 to 5.0, especially preferred from 3.0 to 4. ,5. The content of NCO, referred to that of solids, is from 9 to 50% by weight, preferred from 10 to 30% by weight, especially preferred from 11 to 25% by weight. The monomeric diisocyanate content in the (the mixture of) aliphatic polyisocyanate (s) is preferably less than 10% by weight, particularly preferably less than 2% by weight, most preferably less than 0.5% by weight. weight. Any mixture (s) of aliphatic polyisocyanates, such as, for example, biurets, isocyanurates (trimerized), iminooxadiazinediones, uretdiones, allophanates or adducts with multivalent low molecular weight alcohols such as trimethylolpropane, 1,6-hexanediol, can be used. , 5-pentanediol, diethylene glycol, triethylene glycol, 2, 2, 4-trimethyl-1,3-propanediol, neopentyl glycol, or mixtures thereof. Such polyisocyanates and adducts with multivalent low molecular weight alcohols are described, for example, in J. Prakt. Chem. ,, - and ac arze, em e, Eigenschaften und Anwendungen, editor D. Stoye, W. Freitag, Hanser Verlag, München, Wien 1996. Especially preferred are isocyanurates (trimerized) having a functionality of 3.0 to 4.5. and a monomer content of < 2% by weight and which are prepared, for example, according to a trimerization process analogously to EP 33 09 96. The preparation of (mixtures of) suitable aliphatic polyisocyanates is carried out by oligomerization of diisocyanates as monomers, for example as is described in J. Prakt. Chem. 336, 1994, 185-200. Examples of diisocyanates that can be used as monomers for oligomerization 1, 4-butanediisocyanate, 1,6-hexanediisocyanate (HDI), 3-isocyanatomethyl-3, 3, 5-trimethylcyclohexyl isocyanate (isophorone diisocyanate = IPDI), 2-methyl-1, 5-pentanediisocyanate, 2,2,4-trimethylhexamethylene diisocyanate (TMDI) ), 1,12-dodecanediisocyanate, bis. { isocyanatom il) norbornane and 4,4'-diisocyanatocyclohexylmethane. For the best handling, the (polyisocyanate Al) mixtures can be diluted with up to 50% by weight of conventional lacquer solvent. As a solvent for lacquers, the advantages are that they are not reactants for NCO groups, for example butyl acetate, ethyl acetate, l-methoxy-2-propyl acetate, toluene, 2-butanone, xylene, , 4-dioxane, N-methylpyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide. Preferably, N-methylpyrrolidone is used.

The polyisocyanates Al) are reacted with at least 0.7 equivalents, preferably with at least 0.8 equivalents, more preferably with at least 0.9 equivalents (based on isocyanate) of an aminosilane A2) of formula (I) (RO) nY (3_n) Si-CH2CH2CH2-NHZ (I) wherein R represents methyl, ethyl, Y represents methyl, ethyl, Z represents H, (C1-C12) alkyl, CH2CH2CH2-Si (0R) nY3-n, and n represents the number 1, 2 6 3. Examples of aminosilanes are A2) usable, 3-aminopropyltrimethoxysilane, 3-a-inopropyltriethoxysilane, 1-ami or-2, 2-dimethy1-4-mexophoran, s-r me xs pr p -amine, 3-aminopropyl-methyldiethoxysilane, 3- (N-methyl-amino) -propyl-trimethoxysilane. The aminosilanes used are preferably 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane. Of course, mixtures of various aminosilanes can also be used. The remaining NCO equivalents can be reacted with any I3 compounds reactive with isocyanate, such as, for example, aliphatic and cycloaliphatic alcohols of Ci to Cs and / or aliphatic or cycloaiphatic amines of Ci to C8. Along with them, blocking agents such as butanone oxime, 3,5-dimethylpyrazole, diethyl malonate, e-caprolactam can also be used. It is also possible to convert the NCO equivalents which remain with the usual low and high molecular weight polyhydroxy compounds such as lacquer resin, such as polyacrylates, polyethers, polyesters or polycarbonates (described, for example, in Lackharze, Chemie, Eigenschaften und Anwendungen, publisher D. Stoye, W. Freitag, Hanser Verlag, München, 1996). In the case that these polyols are co-reacted, the reaction with these compounds is eva ally pre-emin ened by the reaction with the aminosilane. Most preferred is an embodiment in which no polyol is employed, but simply less than 5 percent equivalents of all the original isocyanate groups are reacted with the low molecular weight monoalcohol employed as the solvent. As component B) (mixtures of) hydrolysable silanes of formula (II) are used QSi (OX) 3 (II) wherein X represents alkyl (C? -C4) and Q represents H, Ci to C8 alkyl, phenyl, methoxy, ethoxy, 3-glycidyloxy-propyl, 3-aminopropyl and methacryloxypropyl or hydrolysates / condensates preparable from silanes mentioned. Preferably tetraethoxysilane or a hydrolyzate / condensate preparable therefrom is used.

Compounds originating by partial hydrolysis of at least one silane of general formula (II), optionally in a solvent miscible with water, preferably in an aliphatic alcohol, are to be understood by reaction with water in the presence of a catalyst. Naturally, together with the silanes according to the invention of general formula (II), other hydrolysable silanes known in silicone chemistry can also be used. It is also possible to use mixtures of the aforementioned silanes according to the invention. For the preparation of the hydrolysates / condensates, it is preferred that the ratio of water to hydrolyzable groups in the silanes of general formula (II) is in the range of 0.2: 1 to 0.7: 1, preferred of 0, 4: 1 to 0.6: 1. Particularities of the sol-gel process are described, for example, in C. J. Brinker and. Scherer in "Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing", Academic Press New York (1990). The weight data in the lacquer preparation according to the invention refer to the weight of polyisocyanato-aminosilane adduct A) and silane B), depending on the additives and optional additives used. Any solvents of a known type can be added to the paint chemistry. Preferred solvents are aliphatic alcohols such as, for example, ethanol, i-propanol, n-propanol, n-butanol, i-butanol, s-butanol, t-butanol, ether-alcohols as, for example, 1-methoxy-2-propanol or glycol mono-alkyl ether of C? -C4. It may be advantageous to employ dipolar solvents such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, dioxane. Aromatic solvents such as toluene, xylene can also be used, for example in mixture with alcohols. Also suitable are esters and ether esters such as ethyl acetate, butyl acetate, methoxypropyl acetate. Other additives known in the paint industry can also be added, such as inorganic pigments, organic pigments and / or customary coating co-builders such as fillers, plasticizers, catalysts, inhibitors, adhesives, lacquer additives and / or dispersion aids.

The process for the preparation of the condensation products according to the invention can be carried out in the following manner: various processes are conceivable for the preparation of the polyisocyanato-aminosilane adduct A). In a preferred embodiment of the invention, the preparation is carried out according to the following procedure: the polyisocyanate (s) Al) optionally diluted (a) with a solvent and at a preferred temperature of 25 to 30 ° C, it is added dropwise, with cooling, to the aminosilane A2 diluted in a solvent. In this case, it has been shown that the co-employment of alcohols and / or dipolar solvents helps to prevent precipitation and crystallization. If alcohols are used, they are preferably incorporated together with the amino component A2. The polyisocyanate (s) Al is preferably used at a concentration of 30 to 70% in (mixture of) solvents not reactive with isocyanate. Particular preference is given to using (mixtures of) solvents containing from 20 to 100% by weight, preferably from 40 to 100% by weight, of N-methylpyrrolidone. The amine A2 is preferably used dissolved at a concentration of the mixture in admixture, preferably containing from 50 to 100% by weight, particularly preferably from 80 to 100% by weight, of alcohol solvent. To avoid an excess of possibly disturbing amine, it may be advantageous to use the amino component A2 in a lower than stoichiometric ratio. After the reaction, the silane B) is added as well as, optionally, other additives and, optionally, the catalyst. The (mixture of) silane (s) of general formula (II) can be used as such, but also as a hydrolyzate / condensate preparable by hydrolysis with water and catalyst. If the silane (s) is used as such, the lacquer preparation according to the invention is admixed with from 1 to 25% by weight, preferably from 2 to 20% by weight, of water (based on the components A and B, without solvent or additives), optionally together with a hydrolysis catalyst. Suitable hydrolysis catalysts are all the condensation catalysts known in silicone chemistry, such as those described in W. Noli, Chemie und Technologie der Silikone, ch. 5.4, p. 179, ss. Verlag Chemie, Weinheim, 1968. As catalysts, hydrochloric acid, sulfuric acid, p-toluenesulphonic acid, trifluoroacetic acid, acetic acid and formic acid were pre-eminently used. Up to 2%, preferably from 0.01 to 0.3% (based on the solids content of the lacquer) of acid can be used. The (mixture of) silane (s) is preferably employed as an acid hydrolyzate / condensate. In this case, it is advantageous for the water, as well as the catalyst, to be added to the lacquer preparation according to the invention as components of the hydrolyzate / condensate. After the addition of the catalyst or the hydrolyzate / condensate it may be advantageous to stir the mixture according to the invention at room temperature for some time, preferably up to 60 minutes, before application. After this, the sun, usually from 10 to 40%, can be applied by the usual methods such as spraying, flow, squeegee or immersion. For special applications it may eventually be convenient to use a primer. The liquid state time of the mixture ready for coating, according to the type and quantity of the mixture and the mixture used by the employee, is that of at least 1 hour. The coatings, generally 2 to 30 μm thick, already reach a sufficient degree of hardening after 24 hrs. at room temperature. For special applications, however, for example, in the automotive sector, hardening at high temperature can also be carried out. The coatings obtained with the lacquer preparation according to the invention have an improved hardness ratio (pencil hardness greater than 7H), resistance to solvents (0,0,0) and are very flexible. Steel sample plates (140 mm x 65 mm x 0.25 mm), coated, can be bent several times up to an angle of 90 °, without problems, and re-unfold, without the coating being damaged or flaking. With the lacquer preparation according to the invention, any substrates can be coated such as plastics (for example, polycarbonate, polyamide, polyester, ABS, polystyrene, PPO-polyamide blends, PPS), lacquered surfaces, marble, granite, metals, wood, leather and textile objects. em os The following data in% refer to weight. The lacquer preparations according to the invention were applied with a squeegee, with a wet film thickness of 120 μm, on glass plates and steel sample plates (140 mm x 65 mm x 0.25 mm), degreased, aerated at room temperature for 30 minutes and then baked at 130 ° C for 30 minutes.

Testing the resistance of the coating to the solvents: Respectivo little pots filled with a cotton, saturated with xylene, isopropanol or acetone. The jars were placed with the open face on the coated glass plate, so that the solvent could act on the coating. After a time of action of five minutes, the jars were removed. The changes in the coating were investigated visually and by hand exploration.

Evaluation Testing the elasticity of the coating (bending test) The coated test sheets were folded on the edge of a table to an angle of 90 ° and were then re-folded. It was estimated visually whether cracks originated or if the coating was chipped.

Example 1 21.7 g (0.098 mol) of 3-aminopropyltrimethoxysilane are diluted with 21.7 g of ethanol. e mix an, g, eq. e esmo ur Z 4470 (delivery method: 70% in butyl acetate, commercial product of Bayer Ag, isocyanate content 11.5%, NCO functionality = 3.5) with 15.7 g of N-methylpyrrolidone and add drop by drop, at 25-30 ° C, under refrigeration, to the amine solution. Finally, the solution is allowed to stand at room temperature until the NCO band in the IR spectrum has disappeared. The reaction product is in the form of a clear solution, stable to storage, with a solids content of 50%.

Example 2 22.1 g (0.1 mol) of 3-aminopropyltrimethoxysilane are diluted with 105.7 g of ethanol. 19.6 g (0.1 eq) of Desmodur® N are mixed 3300 (delivery method: 100% commercial product of Bayer AG., Isocyanate content 21.5%, NCO functionality = 3.5) with 19.6 g of N-methylpyrrolidone and added dropwise at 25 ° C. -30 ° C, under refrigeration, to the amine solution. Finally, the solution is allowed to stand at room temperature until the NCO band in the IR spectrum has disappeared. The reaction product is present in a standard form, with a solids content of 25%.

EXAMPLE 3 In a three-neck flask with stirrer, inner thermometer, reflux condenser, 114.4 g of tetraethoxysilane (0.55 mol), 140 g of ethanol and 20 g of para-toluenesulfonic acid 0.1 normal are placed together. (approximately 1.1 moles of H20) and stirred for 24 hrs. An exothermic reaction takes place. The silane hydrolyzate, of course, is stable to storage in a closed container, at room temperature, for at least six months.

EXAMPLE 4 75 g of the reaction product of Example 1 are mixed, under stirring, with 25 g of silane hydrolyzate of Example 3 and 36 g of ethanol and stirred at room temperature for 60 minutes. A clear solution is born, with a solids content of 16% and a liquid state time of 180 minutes.

E gp 75 g of the reaction product of Example 2 are mixed, under stirring, with 25 g of silane hydrolyzate of Example 3 and 13.6 g of ethanol and stirred at room temperature for 60 minutes. A clear solution with a solids content of 13% and a liquid state time of 180 minutes is originated.

Comparative Examples Example 6 To a solution of 280 g of tetraethoxysilane (1.35 mol) and 120 g of methyltriethoxysilane (0.67 mol) in 430 g of ethanol, in a three-neck flask with stirrer, internal thermometer, refrigerant After refluxing, 66.6 g of 0.1 normal para-toluenesulfonic acid (approximately 3.7 moles of H20) are added and the mixture is stirred for 24 hours. An exothermic reaction takes place in the course of which a clear silane hydrolyzate originates.

Example 7 30.5 g of the silane hydrolyzate of Example 3 are mixed homogeneously with agitation, with 14.3 g of n-butanol, and 5.2 g of Desmophen® A 665 a, commercially available from Bayer AG) and stirred to a room temperature for 60 minutes. A clear solution with a solids content of 14% is originated. The properties of the coatings of the Examples according to the invention 4 and 5 as well as Comparison Examples 6 and 7 are listed in Table 1: Table 1 1) Visual 2) ASTM D 3363 3) Visual examples 4 and 5, according to the invention, have a very good ratio of mechanical properties, such as very high hardness with simultaneous high flexibility, to very good chemical properties such as, for example, resistance to solvents. Comparison Example 6, as an inorganic sol-gel lacquer, is brittle, cracks when the substrate is repeatedly folded and chipped for the most part. The comparison example 7, like a hybrid lacquer modified with acrylate, has a clearly smaller hardness and a worse resistance to solvents. It is noted that, in relation to this date, the best method known to the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (9)

1. Condensation products of aliphatic-aminosilane polyisocyanate adducts and hydrolysable silanes, which are obtained by reaction of A) 5 to 80% by weight of an adduct of Al) a (a) mixture of aliphatic polyisocyanate (s), which has an average NCO functionality of 2.5 to 5.5 and an isocyanate content of 9 to 50% by weight, with A2) at least 0.7 equivalents of aminosilane of formula (I) (RO) nY3_nSi -CH2CH2CH2 -NHZ (I) wherein R represents methyl, ethyl, Y represents methyl, ethyl, Z represents H, (C1-C12) alkyl, CH2CH2CH2-Si (0R) nY3-n, and n represents the number 1, 2 6 3, and per equivalent of isocyanate A3) optionally other discretionary compounds reactive towards isocyanate, with B) 20 to 95% by weight, preferably 30 to 80% by weight of at least one silane of general formula (II) QSi (OX) 3 (II) wherein X represents alkyl (C? -C) and Q represents H, Ci to Cs alkyl, phenyl, methoxy, ethoxy, 3-glycidyloxy-propyl, 3-aminopropyl and methacryloxypropyl or hydrolysates / condensates preparable from these silanes .

2. Lacquer preparation according to claim 1, characterized in that the average NCO unicity in the (the mixture of) aliphatic polyisocyanate (s) Al) is from 3.0 to 4.5.

3. Lacquer preparation according to claim 1, characterized in that the content of isocyanate groups in the mixture (the mixture of solids, is 10 to 30% by weight).

4. Lacquer preparation according to claim 1, characterized in that the content of monomeric diisocyanate in the (the mixture of) aliphatic polyisocyanate (s) Al) used is less than 2% by weight.

5. Lacquer preparation according to claim 1, characterized in that the (the mixture of) aliphatic polyisocyanate (s) Al) is reacted with at least 0.9 equivalents of amine A2 per equivalent of isocyanate.

6. Lacquer preparation according to claim 1, characterized in that for A2) 3-aminopropyl triethoxysilane or 3-aminopropyltrimethoxysilane is used.

7. Lacquer preparation according to claim 1, characterized in that the silane of the general formula (II) is tetraethoxysilane or a hydrolyzate / condensate preparable therefrom.

. The condensation products according to claim 1 characterized in that the condensation products of polyisocyanate aliphatic-aminosilane adducts and hydrolyzable silanes, which are prepared by reaction of 5 to 80% by weight of an adduct of Al) (a mixture of) polyisocyanate. { s) aliphatic (s), having an average NCO functionality of 2.5 to 5.5 and an isocyanate content of 9 to 50% by weight, with A2) at least 0.7 equivalents of aminosilane of formula (I) ) (RO) nY3_nSÍ -CH2CH2CH2 -NHZ (I) wherein R represents methyl, ethyl, Y represents methyl, ethyl, Z represents H, (C1-C12) alkyl, CH2CH2CH2-Si (0R) nY3-n, and n represents the number 1, 2 or 3, per equivalent of isocyanate A3) optionally other discretionary compounds reactive towards isocyanate, with B) 20 to 95% by weight, preferably 30 to 80% by weight of at least one silane of formula (II) QSi (OX) 3 (II) wherein X represents alkyl (C? ~ C4) and Q represents H, Ci to C8 alkyl, phenyl, methoxy, ethoxy, 3-glycidyloxy-propyl, 3-aminopropyl and methacryloxypropyl or hydrolysates / condensates preparable from these silanes .

9. Use of the lacquer preparation according to claim 1, for the coating of lacquers, plastics, granite, marble, metal, wood, leather and textile objects.