CATALYST COMPONENT FOR ISOCYANATE MODIFICATION

Abstract

The invention relates to a catalyst component for isocyanate modification, comprising at least one cyclic ammonium salt having a cation of the formula I wherein Y is a linear or branched C.sub.2-C.sub.20 segment which is substituted by a hydroxyl group in the 2 position to the charge-bearing nitrogen atom and optionally bears further substituents and is optionally interrupted by heteroatoms from the group of oxygen, sulfur, nitrogen and aromatic rings and optionally has further rings, and the N-bonded substituents R.sup.1 and R.sup.2 are either independently identical or different, substituted or unsubstituted, optionally branched, aliphatic C.sub.1-C.sub.20 radicals, aromatic C.sub.6-C.sub.20 radical or araliphatic C.sub.7-C.sub.20 radicals or the N-bonded substituents R.sup.1 and R.sup.2 form a ring segment X with one another for which the same or different definition given above for Y is applicable, with the proviso that X has a hydroxyl group as substituent in the 2 position to the charge-bearing nitrogen atom or does not have a hydroxyl group as substituent in the 2 position to the charge-bearing nitrogen atom.

Claims

1: A catalyst component for isocyanate modification, comprising at least one cyclic ammonium salt with a cation of formula I, ##STR00013## where Y is a linear or branched C.sub.2-C.sub.20 segment which is substituted by a hydroxyl group in the 2 position to the charge-bearing nitrogen atom, optionally bears further substituents, is optionally interrupted by heteroatoms from the series oxygen, sulfur, nitrogen and also aromatic rings, and optionally includes further rings, and the nitrogen substituents R.sup.1 and R.sup.2 either each independently are identical or different, substituted or unsubstituted, optionally branched, aliphatic C.sub.1-C.sub.20 radicals, aromatic C.sub.6-C.sub.20 radicals or araliphatic C.sub.7-C.sub.20 radicals, or the nitrogen substituents R.sup.1 and R.sup.2 together form a ring segment X, for which the same or different definition given above for Y applies, with the proviso that X has a hydroxyl group in the 2 position to the charge-bearing nitrogen atom as substituent or does not have a hydroxyl group in the 2 position to the charge-bearing nitrogen atom as substituent.

2: The catalyst component as claimed in claim 1, characterized in that Y is a C.sub.4-C.sub.6 alkylene chain segment substituted by a hydroxyl group in the 2 position to the charge-bearing nitrogen atom and optionally bearing further substituents.

3: The catalyst component as claimed in claim 1, characterized in that R.sup.1 and R.sup.2 each independently are identical or different C.sub.1-C.sub.8 alkyl substituents or identical or different benzyl radicals optionally substituted on the aromatic ring.

4: The catalyst component as claimed in claim 1, characterized in that R.sup.1 and R.sup.2 together form a ring segment X, where X is a C.sub.4-C.sub.6 alkylene chain segment optionally bearing further substituents, with the proviso that X is substituted by a hydroxyl group in the 2 position to the charge-bearing nitrogen atom or is not substituted by a hydroxyl group in the 2 position to the charge-bearing nitrogen atom.

5: The catalyst component as claimed in claim 1, characterized in that the segment Y and/or the ring segment X are of linear structure.

6: The catalyst component as claimed in claim 1, characterized in that only Y has a hydroxyl group.

7: A process for modifying isocyanates, in which at least one organic isocyanate having an NCO functionality of >1 is oligomerized and/or polymerized in the presence of a catalyst component as claimed in claim 1.

8: The process as claimed in claim 7, characterized in that the organic isocyanate is an organic diisocyanate and is selected from the group consisting of PDI, HDI, MPDI, TMDI, NTI, IPDI, IMCI, XDI, H6XDI, MDI, TDI, and NBDI.

9: A modified isocyanate, containing at least one structural element covalently bonded via the OH group of the cation of formula I as urethane and/or allophanate group, wherein the cation of formula I has a structure as claimed in claim 1.

10: In a process for the production of foamed or unfoamed plastics and paints, coating compositions, adhesives or additives, the improvement comprising including at least one modified isocyanate as claimed in claim 9.

11: A one- or two-component system, containing a component A), comprising at least one modified isocyanate as claimed in claim 9, and a component B), comprising at least one compound reactive towards NCO groups.

12: A polyurethane body produced by reacting at least one of a monomeric diisocyanate and a polyisocyanate with at least one polyol component in the presence of the catalyst component as claimed in claim 1.

13: The polyurethane body as claimed in claim 12, characterized in that the polyurethane body is a foamed polyurethane body.

14: A coating produced by curing a one- or two-component system as claimed in claim 11, optionally under the action of heat and/or in the presence of a catalyst.

15: A composite component comprising a material which is at least partly joined to a polyurethane body as claimed in claim 12.

Description

EXAMPLES

[0054] All percentages, unless noted otherwise, are to be understood to mean percent by weight.

[0055] Mol % figures were determined by NMR spectroscopy and always relate, unless specified otherwise, to the sum total of the NCO conversion products. The measurements were effected on the Brucker DPX 400 or DRX 700 instruments on about 5% NMR) or about 50% (′.sup.3C NMR) samples in dry C.sub.6D.sub.6 at a frequency of 400 or 700 MHz (′H NMR) or 100 or 176 MHz CC NMR). The reference employed for the ppm scale was small amounts of tetramethylsilane in the solvent with 1H NMR chemical shift 0 ppm. Alternatively, the C.sub.6D.sub.5H present in the solvent was used as reference signal: NMR chemical shift 7.15 ppm; .sup.13C NMR chemical shift 128.02 ppm. Data for the chemical shift of the compounds in question were taken from the literature (cf. D. Wendisch, H. Reiff and D. Dieterich, Die Angewandte Makromolekulare Chemie 141, 1986, 173-183 and literature cited therein and also EP 896 009 A1).

[0056] The dynamic viscosities were determined at 23° C. using a Haake VT 550 viscometer in accordance with DIN EN ISO 3219:1994-10. By measurements at different shear rates, it was ensured that the flow behavior of the polyisocyanate mixtures described according to the invention and also that of the comparative products corresponds to that of ideal Newtonian fluids. The indication of the shear rate can therefore be omitted.

[0057] The NCO content was determined by titration in accordance with DIN EN ISO 11909:2007-05.

[0058] The residual monomer contents were determined by gas chromatography in accordance with DIN EN ISO 10283:2007-11 using an internal standard.

[0059] All reactions were conducted under a nitrogen atmosphere unless stated otherwise.

[0060] The diisocyanates used are products of Covestro AG, D-51365 Leverkusen; all other commercially available chemicals were sourced from Aldrich, D-82018 Taufkirchen.

[0061] The reactants that were not commercially available were obtained by methods known from the literature.

[0062] Described by way of example here is the synthesis of catalysts 1 and 2 according to the following reaction sequence:

Example 1: Preparation of Catalysts 1 and 2

[0063] 10 g of 3-buten-1-ol (approx. 0.14 mol) were initially charged in a 100 ml two-neck flask at room temperature with stirring (magnetic stirrer), 7 drops (approx. 50 mg; approx 0.6 mmol) of pyridine were added thereto and the mixture was cooled to approx. 0° C. by immersion into an ice/water mixture. 17.8 g of thionyl chloride (approx. 0.15 mol) were then added dropwise slowly with stirring (magnetic stirrer), a light yellow coloration arising with brisk evolution of gas. The mixture was then stirred at 80° C. for a further 6 h, the now yellow-brown mixture was rapidly distilled at a slightly reduced pressure into a chilled receiver (−78° C., starting pressure 700 mbar, reduced in stages to 200 mbar) and the distillate obtained was then fractionated slowly at standard pressure over a 10 cm long Vigreux column. The 1-chloro-3-butene boiled at 75+/−1° C. 9.4 g (approx. 0.1 mol; approx. 75% yield, unoptimized) was obtained as colorless liquid.

[0064] This amount of 1-chloro-3-butene was then dissolved in approx. 150 ml of methylene chloride and a total of approx. 25 g of meta-chloroperoxybenzoic acid (77% purity according to manufacturer's data) was introduced in portions with vigorous mechanical stirring. After stirring for 24 hours at room temperature, the mixture was filtered, the filter residue was washed 3 times with approx. 100 ml of methylene chloride each time, the combined filtrates were rapidly distilled at slightly reduced pressure into a chilled receiver (−78° C., starting pressure 700 mbar, reduced in stages to 200 mbar) and the distillate obtained was then fractionated slowly over a 10 cm long Vigreux column first at standard pressure until virtually residue-free removal of the methylene chloride and then further at 50 mbar. The 1-chloro-3,4-butene oxide boiled at 70+/−2° C. 8.5 g (approx. 0.08 mol; approx. 80% yield, unoptimized) was obtained as colorless liquid.

[0065] This amount of 1-chloro-3,4-butene oxide was added dropwise with stirring (magnetic stirrer) to a refluxing mixture of 6.8 g of piperidine (approx. 0.08 mol) and approx. 150 g of water, and the mixture was stirred at 120° C. bath temperature for a further half an hour, freed from all volatile constituents under reduced pressure, and the remaining residue was divided without further purification (yield almost quantitative) and converted a) into the hydroxide by adding an aliquot of methanolic KOH solution and b) into the fluoride by adding a 100% excess of methanolic KF solution.

[0066] The solution obtained under a) was filtered, the precipitate was washed multiple times with 2-ethylhexanol (in the following text: 2-EH) and after concentration (freedom from MeOH checked by means of .sup.1H NMR) was adjusted to the desired content of catalyst 1 (see table 1).

[0067] The solution obtained under b) was filtered, the precipitate was washed multiple times with 2-EH and, after concentration (freedom from MeOH checked by means of .sup.1H NMR) adjusted to the desired content of catalyst 2 with 1.2 equivalents of a 10% solution of anhydrous HF in 2-EH and subsequent dilution with further 2-EH (see table 1).

[0068] Entirely analogously and with comparable yields, it is possible to synthesise further species starting from 4-penten-1-ol on the one hand and other secondary amines such as pyrrolidine or dimethylamine on the other (the aqueous solution was used and the operation was performed under slight positive pressure).

[0069] Further catalysts were obtained by analogous processes from the corresponding quaternary ammonium chlorides, which for their part had been prepared previously from the respective secondary, optionally cyclic, amine and the corresponding chloroalkyloxirane. Higher oligofluorides were obtained by adding appropriate excess HF to the (poly)fluoride solutions obtained in analogy to catalyst 2. Anions other than hydroxide or (poly)fluoride were obtained by salt metathesis with, for example, potassium acetate or potassium pivalate.

[0070] The optimal catalyst concentration for the isocyanate trimerization was determined in exploratory preliminary experiments at 60° C. with HDI (cf. example 2) and the concentration of the catalyst solution was adjusted by diluting with 2-EH such that only negligibly slight gel particle formation, if any, was observed when the catalyst solution was added to the HDI. An overview of the catalysts used can be found in table 1.

TABLE-US-00001 TABLE 1 Overview of the catalysts prepared (the catalyst concentration relates to the active compound (cation and anion)) Catalyst Cation Anion Concentration [%] 1 5-Azoniaspiro[4.5]decan-3- ol hydroxide [00004] OH.sup.−  2 2 5-Azoniaspiro[4.5]decan-3- ol fluoride * 1.2 HF [00005] [F*1.2 HF].sup.− 25 3 6-Azoniaspiro[5.5]undecan- 4-ol [00006] (CH.sub.3).sub.3CC(O)O.sup.− 10 4 6-Azoniaspor[5.5]undecan- 4-ol hydrogendifluoride [00007] [HF.sub.2].sup.− 30 5 1,1-Dimethylpyrrolidin-1- ium-3-ol hydroxide [00008] OH.sup.−  1 6 1,1-Dimethylpyrrolidin-1- ium-3-ol hydrogendifluoride [00009] [HF.sub.2].sup.− 10 7 1,1-Dimethylpiperidin-1- ium-3-ol pivalate [00010] CH.sub.3C(O)O.sup.− 10 8 5-Azoniaspiro[4.4]nonan- 3-ol hydroxide [00011] OH.sup.−  1 9 5-Azoniaspiro[4.4]nonan- 3-ol hydrogendifluoride [00012] [HF.sub.2].sup.− 15

Examples 2 to 9—Isocyanate Modifications According to the Invention

[0071] A jacketed flange vessel heated to the starting temperature desired in each case by means of an external circuit, having a stirrer, reflux condenser connected to an inert gas system (nitrogen/vacuum) and thermometer, was initially charged with 1000 g of HDI which was freed of dissolved gases by stirring under reduced pressure (<1 mbar) for one hour. After venting with nitrogen, the type and amount of catalyst specified in table 2 was metered in, optionally in portions, in such a way that the maximum temperature specified in table 2 was not exceeded. After approx. 1 mol of NCO groups had been converted, as indicated by attainment of an NCO content of around 45.8%, the catalyst was deactivated by addition of an amount of the stopper specified in table 2 that was equivalent to the catalyst, and the mixture was stirred at reaction temperature for a further 30 min and subsequently worked up.

[0072] The workup was effected by vacuum distillation in a thin film evaporator of the short-path evaporator (SPE) type with an upstream preliminary evaporator (PE) (distillation data: pressure: 0.08+/−0.04 mbar, PE temperature: 120° C., ME temp.: 140° C.), with separation of unconverted monomer as distillate and the low-monomer polyisocyanate resin as bottom product (starting run). The polyisocyanate resin was separated and the distillate was collected in a second flange stirring apparatus of identical construction to the first, and made up to the starting amount (1000 g) with freshly degassed HDI. Thereafter, the mixture was treated again with catalyst and the procedure as described at the outset was followed. This procedure was repeated several times, optionally with variation of the reaction temperature (experiments A, B, C, etc.). The results can be found in table 2.

[0073] Finally, the distillate composition was ascertained by gas chromatography. In no case could decomposition products of the catalyst cation be detected (detection limit of approx. 20 ppm).

TABLE-US-00002 TABLE 2 Isocyanate modifications conducted Reaction Catalyst Amount of temperature Example (see table 1) catalyst [g] from-to [° C.] Stopper* 1 A 1 4.3 60 62 1 1 B 1 5.7 60 71 1 1 C 1 6.2 80 90 1 1 D 1 5.9 80 85 1 1 E 1 6.5 100 120 1 1 F 1 6.8 100 140 1 2 A 2 0.85 60 64 3 2 B 2 0.81 60 63 3 2 C 2 0.75 80 88 3 2 D 2 0.61 80 83 3 2 E 2 0.62 100 125 3 2 F 2 0.61 100 104 3 3 A 3 1.42 60 60 1 3 B 3 1.82 60 64 1 3 C 3 2.11 80 85 1 3 D 3 2.00 80 84 1 3 E 3 2.10 100 137 1 3 F 3 2.22 100 101 1 4 A 4 0.91 60 61 2 4 B 4 0.95 60 62 2 4 C 4 0.69 60 61 2 4 D 4 0.67 60 61 2 4 E 4 0.60 60 61 2 4 F 4 0.58 60 61 2 5 A 5 8.5 60 77 1 5 B 5 9.2 60 62 1 5 C 5 9.8 80 88 1 5 D 5 9.5 80 92 1 5 E 5 10.2 100 124 1 5 F 5 10.9 100 103 1 6 A 6 1.71 60 62 2 6 B 6 1.42 60 61 2 6 C 6 1.25 80 85 2 6 D 6 1.02 80 83 2 6 E 6 0.95 100 102 2 6 F 6 0.98 100 105 2 7 A 7 1.32 60 62 1 7 B 7 1.65 60 61 1 7 C 7 1.98 80 83 1 7 D 7 1.98 80 82 1 7 E 7 1.89 100 104 1 7 F 7 2.01 100 104 1 8 A 8 8.7 60 62 1 8 B 8 9.4 60 61 1 8 C 8 10.1 80 83 1 8 D 8 10.2 80 82 1 8 E 8 11.0 100 104 1 8 F 8 10.8 100 104 1 9 A 9 1.12 60 62 3 9 B 9 1.20 60 61 3 9 C 9 1.02 80 83 3 9 D 9 0.98 80 82 3 9 E 9 0.82 100 104 3 9 F 9 0.84 100 104 3 *Stopper: 1: dibutyl phosphate, 2: toluenesulfonic acid, 40% in 2-PrOH, 3: dodecylbenzenesulfonic acid, 70% in 2-PrOH

[0074] The resins obtained were, without exception, light-colored clear viscous liquids with no perceptible amine odor and devoid of extractable catalyst byproducts or conversion products. In the case of use of the fluorine-containing catalysts, the result was mixtures of isocyanurate and iminooxadiazinedione along with a little uretdione. The catalysts with oxygen-containing anions afford products of the isocyanurate type, where, as is the case with the use of the fluorine-containing catalysts, the alcohol (2-EH) used as catalyst solvent is completely converted to the allophanate.

[0075] The recovered HDI is free of impurities that result from the decomposition of the catalyst cation and can be reused without problems in the same or in different processes.