Carbamylation compositions of monovalent metal containing catalysts, polyols and urea compounds and carbamylation processes using the same

Abstract

The present invention provides carbamylation compositions of one or more urea compounds, one or more polyols and a monovalent transition metal or alkali metal catalyst (i), such as lithium ethylhexanoate, which compositions are substantially isocyanate free, enjoy reduced toxicity in comparison to tin catalysts, and which are useful in making polycarbamates which themselves provide compositions for making crosslinked polyurethanes.

Claims

1. A carbamylation composition comprising from 0.1 to 1 wt. %, based on total solids, of one or more catalyst (i) which is a monovalent or alkali metal compound containing an anionic group, one or more urea compounds and one or more polymeric polyols, wherein the ratio of moles of the urea compound to molar equivalents of hydroxyl groups in the one or more polyol (urea:OH) ranges from 0.3:1 to 2.5:1 wherein the catalyst (i) is chosen from alkali metal acetylacetonates, 2,2,6,6-tetramethyl-3,5-heptanedionato cesium, alkali metal esters from alkanoic acids, alkali metal esters from sulfonic acids, alkali metal esters from halogenated sulfonic acids, copper (I) sulfonic metal esters, copper (I) halogenated sulfonic acid metal esters, silver (I) sulfonic acid metal esters, silver (I) halogenated sulfonic acid metal esters, cesium trifluoroacetate, and mixtures thereof.

2. The carbamylation composition as claimed in claim 1, comprising from 0.25 to 0.75 wt. %, based on total solids, of the one or more catalyst (i).

3. The carbamylation composition as claimed in claim 1, wherein the ratio of moles of the urea compound to molar equivalents of hydroxyl groups in the one or more polyols ranges less than 1:1.

4. The carbamylation composition as claimed in claim 1 which are substantially free of isocyanate groups.

5. The carbamylation composition as claimed in claim 4, wherein the amount of isocyanate groups is less than 1 mol %, based on the total molar equivalents of hydroxyl groups plus total moles of isocyanate groups in the carbamylation compositions.

6. The carbamylation composition as claimed in claim 1, wherein the one or more catalyst (i) comprises lithium 2-ethylhexanoate, lithium acetylacetonate, 2,2,6,6-tetramethyl-3,5-heptanedionato cesium, or copper (I) trifluoromethanesulfonate complex (2:1).

7. The carbamylation composition as claimed in claim 1, wherein the one or more urea compounds is urea, biuret, triuret, N-substituted C.sub.1 to C.sub.6 alkyl ureas, such as N-methyl urea or N-ethyl urea, and mixtures thereof.

8. The carbamylation composition as claimed in claim 1, wherein the one or more polyols is chosen from an acrylic polyol and an alkyd polyol.

9. A method of using the carbamylation composition as claimed in claim 1 to make polycarbamates, comprising slowly adding the one or more urea compounds in water to a reaction vessel containing the one or more catalysts (i) and the one or more polymeric polyols to form a reaction mixture and heating to a temperature of from 100 to 180 C. to form the polycarbamate.

10. The carbamylation composition as claimed in claim 1, wherein the one or more catalyst (i) comprises lithium acetylacetonate, 2,2,6,6-tetramethyl-3,5-heptanedionato cesium, or copper (I) trifluoromethanesulfonate complex (2:1).

11. The carbamylation composition as claimed in claim 1, wherein the polymeric polyol has a hydroxyl number of 50 to 250 mg KOH/g polyol, as determined by ASTM D4274-11, Test Method A.

Description

EXAMPLES

(1) The following examples illustrate the present invention but are not intended to limit the scope of the invention.

(2) Carbamylation of an acrylic polyol having a hydroxyl number of 83 and urea were conducted in an array of 48 high throughput reactors (using glass tube inserts) having an internal volume of 35 ml and equipped with a stirrer and a continuous N.sub.2 gas purge of the reactor head space to efficiently remove volatile by products, such as ammonia. Each reactor, included the catalysts indicated in Table 1, below. Trials were carried out in sets of 48 in triplicate, with each set containing four control experiments using dibutyltin oxide (Bu.sub.2SnO) and two control experiments with no catalyst.

(3) In each trial, the glass tubes were pre-weighed loaded with about 9 g of a 65% w/w solution of the acrylic polyol in xylene and were then weighed to determine the exact weight of polyol added. Urea and catalyst were then added based on the weight of the polyol in order to achieve a molar ratio (moles urea/molar equivalents OH) of 0.6 and 1 wt. % of catalyst, based on the weight of polyol, respectively. The tubes were then placed into the bottom part of the high throughput reactor and the reactor head was placed on top and clamped in order to seal the reactor. The reactor was then heated to 140 C. while being purged by N.sub.2 gas. The results from multiple individual trials are shown in Table 1, below.

(4) The final polycarbamate product was analyzed using Fourier transform infrared spectroscopy (FTIR) to monitor the disappearance of hydroxyl groups and thereby measure of the extent of each reaction. The control experiments conducted with Bu.sub.2SnO were used as reference for comparing the catalytic efficiency of the each catalyst (i) tested. The extent of reaction in each tube, as determined by FTIR, was divided by the average of the extent of reaction in the Bu.sub.2SnO in the same set.

(5) The hydroxyl or hydroxyl group conversion from polyol to the final product was determined by monitoring the ratio of the IR spectral peak heights at 3550/3370 wavelengths in the composition. For each catalyst compound tested, the reported relative conversion in Table 1, below, was obtained by dividing the peak height ratios for each catalyst compound to the same ratios found using a control experimental catalyst (Bu2SnO).

(6) TABLE-US-00001 TABLE 1 Urea and Acrylic Polyol Carbamylation Compositions Relative Example Chemical Name Conversion 1A 2,2,6,6-Tetramethyl-3,5-heptanedionato 0.80 cesium 1B 2,2,6,6-Tetramethyl-3,5-heptanedionato 0.73 cesium 1C 2,2,6,6-Tetramethyl-3,5-heptanedionato 0.73 cesium 2A Cesium carbonate 0.78 2B Cesium carbonate 0.75 2C Cesium carbonate 0.75 3A Cesium trifluoroacetate 0.82 3B Cesium trifluoroacetate 0.77 3C Cesium trifluoroacetate 0.76 4A Lithium acetylacetonate 0.73 4B Lithium acetylacetonate 0.67 4C Lithium acetylacetonate 0.62 5A Lithium 2-ethylhexanoate 1.13 5B Lithium 2-ethylhexanoate 1.05 5C Lithium 2-ethylhexanoate 0.95 6A Copper(I) trifluoromethanesulfonate 0.92 complex (2:1) 6B Copper(I) trifluoromethanesulfonate 0.96 complex (2:1) 6C Copper(I) trifluoromethanesulfonate 0.96 complex (2:1) C1A stannous 2-ethylhexanoate 1.13 C1B stannous 2-ethylhexanoate 1.10 C1C stannous 2-ethylhexanoate 0.95 C2A No catalyst 0.75 C2B No catalyst 0.74 C2C No catalyst 0.72 C2D No catalyst 0.70 C2E No catalyst 0.67 C2F No catalyst 0.67 C2G No catalyst 0.67 C2H No catalyst 0.66 C2I No catalyst 0.65 C2J No catalyst 0.64 C2K No catalyst 0.63 C2L No catalyst 0.61 C2M No catalyst 0.59 C2N No catalyst 0.54 C3A Bu2SnO 1.12 C3B Bu2SnO 1.08 C3C Bu2SnO 1.06 C3D Bu2SnO 1.06 C3E Bu2SnO 1.05 C3F Bu2SnO 1.05 C3G Bu2SnO 1.04 C3H Bu2SnO 1.04 C3I Bu2SnO 1.04 C3J Bu2SnO 1.04 C3K Bu2SnO 1.03 C3L Bu2SnO 1.02 C3M Bu2SnO 1.01 C3N Bu2SnO 1.01 C3N Bu2SnO 0.99 C3O Bu2SnO 0.99 C3P Bu2SnO 0.98 C3Q Bu2SnO 0.97 C3R Bu2SnO 0.97 C3S Bu2SnO 0.97 C3T Bu2SnO 0.97 C3U Bu2SnO 0.96 C3V Bu2SnO 0.96 C3W Bu2SnO 0.95 C3X Bu2SnO 0.94 C3Y Bu2SnO 0.94 C3Z Bu2SnO 0.93 C3AA Bu2SnO 0.91

(7) The relative performance of tested compounds in the reaction between acrylic polyol and urea is tabulated in Table 1, above. As shown in the table and allowing for deviations between the various trials, the catalyst (i) of the present invention, especially lithium ethylhexanoate, effectively catalyzed carbamylation of the polyols in the carbamylation composition. In the case of lithium ethylhexanoate and copper(I) trifluoromethanesulfonate complex (2:1), the inventive catalysts (i) performed about as well as the comparative tin containing catalyst.