PRODUCTION PROCESS FOR AMINO ALCOHOLATES

Abstract

The invention relates to a method for producing at least one metal amino alcoholate, at least comprising the following steps (A) providing at least one amino alcohol, (B) adding at least one basic compound to the at least one amino alcohol provided in step (A) in order to obtain at least one corresponding amino alcoholate, and (C) adding at least one metal halogenide to the mixture obtained in step (C) in order to obtain a corresponding metal amino alcoholate, wherein in step (C) the at least one metal halogenide is added as a solution in a protic solvent at a concentration of 2.0 to 35.0 wt. %; a solution containing at least one metal alcoholate obtained in this manner; the use of the solution to produce a composition; a corresponding composition; the use of said composition to produce single- or multi-layer paint structures; a method for single- or multi-layer coating of a substrate with a paint structure; and a substrate coated in this manner.

Claims

1. A method for preparing at least one metal amino alkoxide, comprising: (A) providing at least one amino alcohol, (B) adding at least one basic compound to the at least one amino alcohol provided in step (A) to obtain at least one corresponding amino alkoxide, and (C) adding at least one metal halide to the mixture obtained in step (B) to obtain the corresponding at least one metal amino alkoxide, characterized in that in step (C) the at least one metal halide is added as a solution in a protic solvent at a concentration of 2.0 to 35.0% by weight.

2. The method as claimed in claim 1, characterized in that the metal is selected from the group consisting of tin, titanium, bismuth, and mixtures thereof.

3. The method as claimed in claim 1, characterized in that the at least one basic compound added in step (B) a solution in a protic solvent.

4. The method as claimed claim 1, characterized in that the at least one amino alcohol provided in step (A) of the method conforms to the general formula (I) or (II)
HO—X-D-Y—OH  (I)
HO—X-D-Z-D-Y—OH  (II) wherein
D is —O—, —S— or —N(R1)-, wherein at least one D present is —N(R1)-, wherein R1 is a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic radical or an optionally substituted aromatic or araliphatic radical having up to 20 carbon atoms, which may optionally comprise heteroatoms from the group of oxygen, sulfur and nitrogen, or is hydrogen, X, Y and Z are identical or different radicals selected from alkylene radicals of the formulae —C(R2)(R3)-, —C(R2)(R3)-C(R4)(R5)- or —C(R2)(R3)-C(R4)(R5)-C(R6)(R7)- or ortho-arylene radicals of the formulae ##STR00003## wherein R2 to R11 are each independently saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic radicals or optionally substituted aromatic or araliphatic radicals having up to 20 carbon atoms, which may optionally comprise heteroatoms from the group of oxygen, sulfur and nitrogen, or are hydrogen.

5. The method as claimed in claim 1, characterized in that the at least one amino alcohol is selected from the group consisting of N-cyclopentyldiethanolamine, N-cyclohexyldiethanolamine, N-cyclopentyldiisopropanolamine, N-cyclohexyldiisopropanolamine, N-butyldiethanolamine, N-butyldiisopropanolamine, N-methyl-N,N-bis(2-hydroxybutyl)amine, N-butyl-N,N-bis(2-hydroxybutyl)amine, N-cyclohexyl-N,N-bis(2-hydroxybutyl)amine, and mixtures thereof.

6. The method as claimed in claim 1, characterized in that the at least one basic compound is selected from the group consisting of ammonia, an alkali metal, and an alkaline earth metal salt of the anion of the at least one protic solvent.

7. The method as claimed in claim 1, characterized in that at least one protic solvent is selected from the group consisting of alcohols.

8. A solution comprising at least one metal alkoxide, prepared by the method according to claim 1.

9. (canceled)

10. A composition comprising at least one polyisocyanate, at least one NCO-reactive compound and a solution as claimed in claim 8.

11. A composition comprising at least one metal amino alkoxide, at least one solvent selected from the group consisting of esters, aromatic solvents, lactones, carbonates and mixtures thereof, and at least one polyisocyanate.

12. The composition as claimed in claim 11, characterized in that after storage for at least 3 months, at a maximum temperature of 40° C., said composition has a Hazen color number, measured spectrophotometrically according to DIN EN ISO 6271-2:2005-03, of less than 150 APHA.

13. (canceled)

14. A method for single-layered or multi-layered coating of a substrate with a coating system by applying a composition as claimed in claim 10 to the substrate.

15. A substrate coated with a single-layered or multi-layered coating system comprising a composition as claimed in claim 10 wherein the substrate is a chassis of a land vehicle, aircraft or watercraft, or a part thereof.

16. A substrate coated with a single-layered or multi-layered coating system comprising a composition obtained by the method as claimed in claim 14, wherein the substrate is a chassis of a land vehicle, aircraft or watercraft, or a part thereof.

Description

EXAMPLES

[0086] Methods and Materials:

[0087] The Hazen colour number was measured by spectrophotometry according to DIN EN ISO 6271-2:2005-03 with a LICO 400 spectrophotometer from Lange, Germany.

[0088] Unless otherwise stated, the compounds used were obtained from chemical retailers, for example Sigma-Aldrich, Merck KGaA, Darmstadt, Germany or BASF SE, Ludwigshafen, Germany, and were each present in a purity of more than 99% by weight.

[0089] The identity and purity of each of the newly synthesized compounds was unequivocally determined from the results of NMR spectroscopy, gas chromatography and mass spectrometry investigations.

[0090] Preparation methods for the commercially unavailable N-alkyldialkanolamines used as ligands for the catalysts in Examples a), b), c), d), f), g), h) and i)

[0091] General Preparation Method

[0092] The particular amine specified in Table 1 below was placed in a 2 l laboratory autoclave under a nitrogen atmosphere. The amount weighed in was such that it was in a molar ratio of 1:2 with the epoxides metered in, resulting in a theoretical total yield of 1500 g in each case. Oxygen was removed at room temperature by four cycles of pressurization of the autoclave with nitrogen to 3 bar (a) and subsequent release of the positive pressure to standard pressure. After the autoclave had been closed, its contents were heated to 90° C. (reaction temperature) with stirring (800 rpm, cross-bar stirrer). After reaching the reaction temperature and a reaction start pressure depending on the respective amine, the epoxide specified in the table was metered into the headspace of the autoclave with continuous stirring in such a way that a pressure of 5 bar was not exceeded. In relation to the amount of amine weighed out, twice the amount of epoxide was used in each case. After the end of the epoxide metered addition, a post-reaction phase followed. This post-reaction phase was considered to be completed when the pressure drop was below 20 mbar/h. The product was subsequently devolatilized at 90° C. under reduced pressure (30 mbar) over a period of 30 minutes.

TABLE-US-00001 TABLE 1 Reactants used Example Amine used Epoxide used a) Cyclopentylamine Ethylene oxide* b) Cyclohexylamine Ethylene oxide* c) Cyclopentylamine Methyloxirane (propylene oxide) d) Cyclohexylamine Methyloxirane (propylene oxide) e) n-Butylamine Methyloxirane (propylene oxide) g) Methylamine** Ethyloxirane (1-Butene oxide) h) n-Butylamine Ethyloxirane (1-Butene oxide) i) Cyclohexylamine Ethyloxirane (1-Butene oxide) *In the experiments in which ethylene oxide (oxirane) was metered in, a nitrogen inlet pressure of 2.8 bar was set before the start of epoxide metered addition. **Deviating from the procedure given in the general preparation method, a 40% aqueous solution of methylamine was used here. The reaction temperature was 75° C. After the end of the ethyloxirane metered addition, the water was removed in vacuo at 80° C. over a period of 3 hours.

[0093] The alkanolamines thus obtained were then purified by rectification in vacuo and obtained as colorless liquids or oils. Refractive indices and boiling points of the compounds obtained are given in Table 2.

TABLE-US-00002 TABLE 2 Refractive indices and boiling points of the amino alcohols Kp @ 0.1 Example Amino alcohol n.sub.D.sup.20 mbar [° C.] a) N-Cyclopentyldiethanolamine 1.4961 110 b) N-Cyclohexyldiethanolamine 1.4935 120 c) N-Cyclopentyldiisopropanolamine 1.4785 117 d) N-Cyclohexyldiisopropanolamine 1.4804 100 f) N-Butyldiisopropanolamine 1.4518 73 g) N-Methyl-N,N- 1.4531 66 bis(2-hydroxybutyl)amine h) N-Butyl-N,N- 1.4546 97 bis(2-hydroxybutyl)amine i) N-Cyclohexyl-N,N- 1.4798 127 bis(2-hydroxybutyl)amine

Examples 1a to 1i (Non-Inventive, SnCl.SUB.4 .Undiluted)

[0094] A 1 l four-necked flask equipped with a jacketed coil condenser (brine-cooled), PTFE-jacketed internal thermometer (PT 100), mechanical PTFE-jacketed stirrer and pressure-equalizing dropping funnel was respectively initially charged under an inert gas atmosphere (dry nitrogen) with

a) 133.0 g of N-cyclopentyldiethanolamine,

b) 143.8 g of N-cyclohexyldiethanolamine,

c) 154.6 g of N-cyclopentyldiisopropanolamine,

d) 165.3 g of N-cyclohexyldiisopropanolamine,

e) 123.8 g of N-butyldiethanolamine,

f) 145.3 g of N-butyldiisopropanolamine,

[0095] g) 134.6 g of N-methyl-N,N-bis(2-hydroxybutyl)amine,
h) 166.9 g of N-butyl-N,N-bis(2-hydroxybutyl)amine or
i) 186.9 g of N-cyclohexyl-N,N-bis(2-hydroxybutyl)amine
and 276.5 g of a 30% methanolic sodium methoxide solution was added in each case. The reactor contents were uniformly adjusted to ca. 600 ml by adding further methanol. Then, with stirring and external brine cooling (internal temperature 0 to 5° C.), 100 g of freshly distilled tin tetrachloride were slowly added dropwise in each case using a pressure-equalizing dropping funnel.

[0096] There was an onset of significant mist binding in the reactor and solids separation in the liquid. Irrespective of the speed of dropwise addition and stirring, caking formed on the dropping funnel and sometimes also above the liquid surface in a manner that was difficult to control, and even vigorous stirring and the application of a vacuum until the reaction mixture boiled could not break it up reproducibly and completely and convert it to the liquid phase.

[0097] After filtration, washing of the precipitates with 3 times ca. 100 ml of fresh methanol, concentration in vacuo to constant pressure at a maximum product temperature of 30° C. and ca. 0.1 mbar, the product was purged with nitrogen and each time taken up with ca. 500 ml of n-butyl acetate, undissolved components were filtered off and the product was distilled on an effective column at gradually reduced pressure until pure n-butyl acetate was present at the head, i.e. methanol was no longer present in the receiver.

[0098] The clear, slightly discolored solutions remaining as distillation bottoms (Hazen color number <200 Apha in each case) were adjusted to a uniform 1.0% by weight tin content—determined in each case by means of X-ray fluorescence analysis—and used to produce the products listed in example series 3-1.

[0099] Experiments 1a to 1 i were repeated, with the difference that 99.5 g (experiments 1a-1 to 1i-1) or 100.5 g (experiments 1a-2 to 1i-2) of freshly distilled tin tetrachloride were added. The course of the reaction was optically identical; in terms of analysis (NMR, elemental analysis, color determination) there were practically no apparent differences in the respective 3 products obtained of the same chemical structure. These solutions were also used to prepare the products listed in example series 3-1.

Examples 2a to 2i (Inventive, SnCl.SUB.4 .Diluted)

[0100] A 1 l four-necked flask equipped with a jacketed coil condenser (brine-cooled), PTFE-jacketed internal thermometer (PT 100), mechanical PTFE-jacketed stirrer and pressure-equalizing dropping funnel was respectively initially charged under an inert gas atmosphere (dry nitrogen) with

a) 13.3 g of N-cyclopentyldiethanolamine,

b) 14.4 g of N-cyclohexyldiethanolamine,

c) 15.5 g of N-cyclopentyldiisopropanolamine,

d) 16.5 g of N-cyclohexyldiisopropanolamine,

e) 12.4 g of N-butyldiethanolamine,

f) 14.5 g of N-butyldiisopropanolamine,

[0101] g) 13.5 g of N-methyl-N,N-bis(2-hydroxybutyl)amine,
h) 16.7 g of N-butyl-N,N-bis(2-hydroxybutyl)amine or
i) 18.7 g of N-cyclohexyl-N,N-bis(2-hydroxybutyl)amine
and 27.7 g of a 30% methanolic sodium methoxide solution was added in each case. The reactor contents were uniformly adjusted to ca. 100 ml by adding further methanol.

[0102] Then, with stirring and external brine cooling (internal temperature 0 to 5° C.), in each case 1000 g of a virtually colourless, clear, liquid mixture consisting of 100 g of freshly distilled tin tetrachloride and 900 g of methanol (hereinafter: 10% methanolic SnCl.sub.4 solution) were slowly added dropwise using a pressure-equalizing dropping funnel.

[0103] There was no binding of mist in the reactor and the separation of solids in the liquid appeared to be similar to that in experiment series 2. In no case was the formation of caking observed on the dropping funnel or above the liquid surface.

[0104] The clear, virtually colorless solutions remaining after work-up as described under 2 (Hazen color number <100 Apha in each case) were adjusted to a uniform 1.0% by weight tin content—determined in each case by means of X-ray fluorescence analysis—and used to produce the products listed in example series 4-2.

[0105] Experiments 2a to 2i were repeated, with the difference that 995 g (experiments 2a-1 to 2i-1) or 1005 g (experiments 2a-2 to 2i-2) of the 10% methanolic SnCl.sub.4 solution were added. The course of the reaction was optically identical; in terms of analysis (NMR, elemental analysis, color determination) there were practically no apparent differences in the respective 3 products obtained of the same chemical structure. These solutions were also used to prepare the products listed in example series 3-2.

Example Series 3

[0106] (Preparation of Mixtures of Tin(IV) Amino Alkoxides and Polyisocyanates; Comparative Experiments: Series 3-1, Experiments According to the Invention: Series 3-2)

[0107] In each case 90 g of an HDI polyisocyanate (isocyanurate type, product Desmodur N 3300 from Covestro AG) were mixed with 6.75 g each of the solutions obtained in Example 1 or Example 2 and then made up to a uniform 100 g in each case by adding n-butyl acetate.

[0108] The mixtures were homogenized at 50° C. for one hour and then stored at 40° C. After visually observing a clear change in the habitus of the sample, the colour, viscosity and NCO content were determined.

[0109] For 80% of the products based on the tin(IV) amino alkoxide solutions obtained in the comparative experiment series 1a to 1i, 1a-1 to 1i-1 and 1a-2 to 1i-2, this maximum storage time was less than 2 months. None of the samples were visually impeccable for longer than 4 months, i.e. the Hazen color number was above 150 Apha in each case.

[0110] In a non-specific manner, strong color deepening and viscosity increases sometimes occurred in parallel, but mostly only color deepening (Hazen color number >>500 Apha) towards deep yellow and orange hues were observed.

[0111] In contrast, surprisingly, no such effects occurred in series 3-2 according to the invention when using the tin(IV) amino alkoxide solutions obtained by the method according to the invention according to Examples 2a to 2i/2a-1 to 2i-1 and 2a-2 to 2i-2. None of the samples were remarkable in terms of color or viscosity/NCO content after storage for 4 months.