Patent Description:
One of the widely used class of catalysts for the reaction of polyols with amides or esters is tin-based catalysts. However, tin-based materials are now banned in coating materials in some regions such as Europe. Alternative catalysts for the reaction of polyols with amides or esters would therefore be desirable.

<CIT> discloses coatings derived from a curable coating composition comprising: (a) a non-polymeric organic compound having a molecular weight of from <NUM> to <NUM> comprising a plurality of carbamate active hydrogens, and (b) a second component comprising a compound having a plurality of functional groups that are reactive with said carbamate active hydrogens.

<CIT> discloses an intermediate product comprising a mixture of organic carbonates and carbamates that is obtained by reacting urea, substituted urea, a salt or ester of carbamic acid or its N-substituted derivatives with polyalkylene glycols, polyester-polyols, polyether-polyols and/or polyvinyl alcohols, optionally in presence of an ammonia-cleavage catalyst.

The instant invention is a process to produce <NUM>% solids polycarbamate comprising less than <NUM> wt% total of biuret, cyanuric acid, and polyallophanate, which is obtainable by a process to prepare polycarbamate comprising:
adding urea to a polyol selected in the group consisting of oligomers or polymers derived from hydroxyl-containing acrylic monomeric units in the presence of at least one catalyst selected from the group consisting of: Al(III) acetylacetonate, Bismuth(III) trifluoromethanesulfonate, Bi(III) tri(<NUM>-ethylhexanoate), wherein the process achieves at least a <NUM>% conversion of hydroxyl groups of the polyol.

The instant invention is a process to produce <NUM>% solids polycarbamate comprising less than <NUM> wt% total of biuret, cyanuric acid, and polyallophanate, which is obtainable by a process to prepare polycarbamate comprising:
adding urea to a polyol selected in the group consisting of oligomers or polymers derived from hydroxyl-containing acrylic monomeric units in the presence of at least one catalyst selected from the group consisting of: Al (III) acetylacetonate, Bismuth(III) trifluoromethanesulfonate, Bi(III) tri(<NUM>-ethylhexanoate), wherein the process achieves at least a <NUM>% conversion of hydroxyl groups of the polyol.

In embodiments of the process, the urea may be added in either solid or liquid form. In a specific embodiment, the urea is added in liquid form.

The liquid form of the urea (or "liquid urea") may be achieved in any acceptable manner. For example, the urea may be dissolved in a first solvent. Alternatively, the urea may be melted. In yet another alternative, the urea may be suspended in a clathrate. A urea clathrate may also be known as a urea inclusion compound and may have the structure as described in "<NPL> and <NPL>.

The liquid form of the urea may alternatively be present in a combination of liquid forms.

In a particular embodiment, the urea is dissolved in water. In another embodiment, the urea may be dissolved in a mixture of two or more first solvents. Such first solvents include organic solvents. In an alternative embodiment, the urea is dissolved in one or more first solvents selected from water and organic alcohols. In one embodiment, urea is partially soluble in the first solvent or mixture of first solvents. In yet another embodiment, urea is fully soluble in the first solvent or mixture of first solvents.

The polyol used in the present invention is selected from the group consisting of oligomers or polymers derived from hydroxy-containing acrylic monomeric units.

As used herein, the term "polyol" means an organic molecule having at least <NUM> --OH functionalities. As used herein, the term "polyester polyol" means a subclass of polyol that is an organic molecule having at least <NUM> alcohol (--OH) groups and at least one carboxylic ester (CO<NUM>--C) functionality. The term "alkyd" means a subclass of polyester polyol that is a fatty acid-modified polyester polyol wherein at least one carboxylic ester functionality is preferably derived from an esterification reaction between an alcoholic --OH of the polyol and a carboxyl of a (C<NUM>-C<NUM>) fatty acid. In one exemplary embodiment, the polyol component comprises hydroxyethyl acrylate. In another exemplary embodiment, the polyol component comprises hydroxyethyl methacrylate.

The reaction mixture may comprise from <NUM> to <NUM> percent by weight of polyol; for example, from <NUM> to <NUM> percent by weight of polyol. In one embodiment, the polyol has a functional structure of a <NUM>,<NUM>-diol, <NUM>,<NUM>-diol, or combinations thereof.

The polyol can be non-cyclic, straight or branched; cyclic and nonaromatic; cyclic and aromatic, or a combination thereof. In some embodiments the polyol comprises one or more non-cyclic, straight or branched polyols. For example, the polyol may consist essentially of one or more non-cyclic, straight or branched polyols.

In one embodiment, the polyol consists essentially of carbon, hydrogen, and oxygen atoms. In another embodiment, the polyol consists of primary hydroxyl groups. In yet another embodiment, the hydroxyl groups are in the <NUM>,<NUM> and/or <NUM>,<NUM> configuration. Exemplary polyol structures are shown below for illustrative purposes.

Polyol of the inventive process is selected in the group consisting of oligomers or polymers derived from hydroxy-containing acrylic monomeric units. Suitable monomers may be, but are not limited to, hydroxyethyl acrylate, hydroxypropyl acrylate , hydroxybutyl acrylate, hydroxydodecyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxydodecyl methacrylate, hydroxybutyl vinyl ether, diethylene glycol vinyl ether and a combinations thereof. The polyol useful in embodiments may be prepared by reacting at least one hydroxyl-containing monomer with one or more monomers. Suitable monomers may be, but are not limited to, vinyl monomers such as styrene, vinyl ether, such as ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, ester of unsaturated carbonic acid and dicarbonic acid, such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, <NUM>-ethylhexyl acrylate, <NUM>-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, dimethyl maleate and a mixture thereof.

The addition of the urea to polyol may be accomplished by any means. In a particular embodiment of the process, the adding the urea to the polyol is conducted in a batch manner. In a particular embodiment of the process, the adding the urea to the polyol is conducted in a semi-batch manner. In one embodiment, the urea is added at a constant rate over a period of time in which the reaction proceeds. In yet another embodiment, the urea is added to the polyol at more than one rate, with the rate changing over the time period in which the reaction proceeds. In yet another embodiment, the urea is added to the polyol using a pulsed constant rate in which the urea is added at a rate for a first period of time, followed by a second period of no urea addition, followed by urea addition at the same rate for a third period of time, and so on. In another alternative embodiment, the urea in liquid form is added to the polyol using a pulsed variable rate in which the urea is added at a first rate for a first period of time, followed by a second period of no urea addition, followed by urea addition at a second rate for a third period of time, and so on.

In one embodiment of the process, the polyol is complete polyol in the absence of any solvent. In an alternative embodiment of the process, the polyol is dissolved in a second solvent prior to the adding the urea to the dissolved polyol. The second solvent may be any solvent or mixture of solvents in which the polyol is soluble or partially soluble. In certain embodiments, the first and second solvents form a heterogeneous azeotrope allowing removal of the first solvent by decantation or other means. In certain embodiments, removal of the first solvent from a heterogenous azeotrope permits concurrent removal of certain by-products, such as ammonia, which are soluble in the first solvent. In yet an alternative embodiment, the first and second solvents form a heterogeneous azeotrope allowing removal of the first solvent and further wherein the second solvent is returned to the reactor.

In yet another embodiment, the urea is added to the polyol in a gradient method, as described in pending <CIT>, entitled "Process to Produce Polycarbamate Using a Gradient Feed of Urea.

The process achieves at least a <NUM>% conversion of hydroxyl groups of the polyol. All individual values and subranges from at least <NUM>% conversion are included herein and disclosed herein; for example, the hydroxyl conversion may range from a lower limit of <NUM>%, or in the alternative, the hydroxyl conversion may range from a lower limit of <NUM>%, or in the alternative, the hydroxyl conversion may range from a lower limit of <NUM>%, or in the alternative, the hydroxyl conversion may range from a lower limit of <NUM>%, or in the alternative, the hydroxyl conversion may range from a lower limit of <NUM>%, or in the alternative, the hydroxyl conversion may range from a lower limit of <NUM>% or in the alternative, the hydroxyl conversion may range from a lower limit of <NUM>%, or in the alternative, the hydroxyl conversion may range from a lower limit of <NUM>%.

Catalysts included in embodiments of the inventive process are selected from the group consisting of: Al(III) acetylacetonate, Bismuth(III) trifluoromethanesulfonate, Bi(III) tri(<NUM>-ethylhexanoate).

In one embodiment of the process, adding the urea to the polyol occurs in the presence of any one or more of the foregoing catalysts.

The instant invention provides a polycarbamate, in accordance with any of the preceding embodiments, where a <NUM>% solids product of the polycarbamate comprises less than <NUM> wt% total of biuret, cyanuric acid, and polyallophanate. All individual values and subranges from less than <NUM> wt% are included herein and disclosed herein; for example, the total amount of biuret, cyanuric acid, and polyallophanate in a <NUM> wt% solids polycarbamate product may be from an upper limit of <NUM> wt%, or in the alternative, from an upper limit of <NUM> wt%, or in the alternative, from an upper limit of <NUM> wt%, or in the alternative, from an upper limit of <NUM> wt%, or in the alternative, from an upper limit of <NUM> wt%, or in the alternative, from an upper limit of <NUM> wt%.

The polycarbamate according to the embodiments disclosed herein may be used in coating compositions. Such coatings may include, for example, polyurethane from crosslinking reaction of the polycarbamate and components with multiple aldehyde functionalities. Exemplary end uses for such coatings include metal, ceramic, wood and plastic coatings, including for example wind blade coatings and automotive coatings.

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

A <NUM>-L reactor with heating mantle was used in the reaction. The reactor was equipped with an agitator, a thermal-couple and a nitrogen sparger. A water-cooled condenser was connected to the adaptor on the reactor lid. The overhead condensate was collected by a receiver and the non-condensable went through a bubbler filled with mineral oil and then entered a <NUM>-L scrubber filled with water.

<NUM> PARALOID AU-608X polyol (commercially available from The Dow Chemical Company) which consists of <NUM>% solid and <NUM>% solvent (xylenes) was added to the reactor, which had <NUM> mol hydroxyl functionality. <NUM> Al (III) acetylacetonate (<NUM>% pure) was added to the reactor. <NUM> urea (<NUM>% pure) was used in this reaction. The heating mantle was started and set at <NUM>. The nitrogen sparging flow rate was set at <NUM> sccm. The reaction mixture was agitated at <NUM> rpm and then adjusted to <NUM> rpm when the reactor temperature was over <NUM>. When the reactor temperature reached <NUM>, <NUM>% of urea (<NUM>) was added to the reactor. The reaction timer was also started. The urea was fed to the reactor in a semi-batch manner. The feeding rates are shown in Table <NUM>.

The reaction was carried out until the total reaction time reached <NUM> hours. The reaction temperature is between <NUM>-<NUM>. After the reaction was complete, the heating mantle was shut down and the agitation rate was reduced to <NUM> rpm. When the reactor temperature dropped to <NUM>, the polycarbamate product was poured out from the reactor. The final product was analyzed using <NUM>C NMR. The hydroxyl conversion of the final product was <NUM>%. The byproduct levels are shown in Table <NUM>.

The final polycarbamate product color was Gardner level <NUM>.

<NUM> PARALOID AU-608X polyol which consists of <NUM>% solid and <NUM>% solvent (xylenes) was added to the reactor, which had <NUM> mol hydroxyl functionality. <NUM> Al(III) isopropoxide (<NUM>% pure) was added to the reactor. <NUM> urea (<NUM>% pure) was used in this reaction. The heating mantle was started and set at <NUM>. The nitrogen sparging flow rate was set at <NUM> sccm. The reaction mixture was agitated at <NUM> rpm and then adjusted to <NUM> rpm when the reactor temperature was over <NUM>. <NUM>% of Urea (<NUM>) was added to the reactor when the reactor temperature reached <NUM> and the reaction timer was started. The reaction was carried out between <NUM>-<NUM>. When the reaction time reached <NUM> hours, <NUM>% urea (<NUM>) was added to the reactor. When the reaction time reached <NUM> hours, the rest <NUM>% urea (<NUM>) was added to the reactor. The total reaction time was <NUM> hours. The reaction temperature is between <NUM>-<NUM>. After the reaction was complete, the heating mantle was shut down and the agitation rate was reduced to <NUM> rpm. When the reactor temperature dropped to <NUM>, the polycarbamate product was poured out from the reactor. The final product was analyzed using <NUM>C NMR. The hydroxyl conversion of the final product was <NUM>%. The byproduct levels are shown in Table <NUM>.

A <NUM>-L reactor with heating mantle was used in the reaction. The reactor was equipped with an agitator, a thermal-couple and a nitrogen sparger. A heated condenser was connected to the adaptor on the reactor lid. A heating batch equipped with a circulation pump was used to heat water circulating in the condenser. The overhead condensate was collected by a receiver and the non-condensable went through a bubbler filled with mineral oil and then entered a <NUM>-L scrubber filled with water.

<NUM> PARALOID AU-608X polyol which consists of <NUM>% solid and <NUM>% solvent (xylenes) was added to the reactor, which had <NUM> mol hydroxyl functionality. <NUM> Al(III) acetylacetonate (<NUM>% pure) was added to the reactor. The heating mantle was started and set at <NUM>. The heating batch for the overhead condenser was set at <NUM>. The nitrogen sparging flow rate was set at <NUM> sccm. The reaction mixture was agitated at <NUM> rpm and then adjusted to <NUM> rpm when the reactor temperature was over <NUM>. When the reactor temperature reached <NUM>, <NUM> (<NUM>% pure) methyl carbamate was added to the reactor. When the reactor temperature reached <NUM>, the reaction timer was started.

The total reaction time was <NUM> hours. The reaction temperature is between <NUM>-<NUM>. After the reaction was complete, the heating mantle was shut down and the agitation rate was reduced to <NUM> rpm. When the reactor temperature dropped to <NUM>, the polycarbamate product was poured out from the reactor. The final product was analyzed using <NUM>C NMR. The hydroxyl conversion of the final product was <NUM>%.

<NUM> PARALOID AU-608X polyol which consists of <NUM>% solid and <NUM>% solvent (xylenes) was added to the reactor, which had <NUM> mol hydroxyl functionality. <NUM> Bismuth (III) Trifluoromethanesulfonate (<NUM>% pure) was added to the reactor. The heating mantle was started and set at <NUM>. The nitrogen sparging flow rate was set at <NUM> sccm. The reaction mixture was agitated at <NUM> rpm and then adjusted to <NUM> rpm when the reactor temperature was over <NUM>. When the reactor temperature reached <NUM>, <NUM> urea (<NUM>% pure) was added to the reactor. The reaction timer was also started.

The total reaction time was <NUM> hours. The reaction temperature is between <NUM>-<NUM>. After the reaction was complete, the heating mantle was shut down and the agitation rate was reduced to <NUM> rpm. When the reactor temperature dropped to <NUM>, the polycarbamate product was poured out from the reactor. The final product was analyzed using <NUM>C NMR. The hydroxyl conversion of the final product was <NUM>%. The byproduct levels are shown in Table <NUM>.

<NUM> PARALOID AU-608X polyol which consists of <NUM>% solid and <NUM>% solvent (xylenes) was added to the reactor, which had <NUM> mol hydroxyl functionality. The heating mantle was started and set at <NUM>. The nitrogen sparging flow rate was set at <NUM> sccm. The reaction mixture was agitated at <NUM> rpm and then adjusted to <NUM> rpm when the reactor temperature was over <NUM>.

<NUM> Bismuth (III) Trifluoromethanesulfonate (<NUM>% pure) and <NUM> urea (<NUM>% pure) were used for this reaction. Both urea solid and catalyst (Bismuth (III) Trifluoromethanesulfonate) were both added to the reactor in a semi-batch manner. When the reactor temperature reached <NUM>, the addition of urea and catalyst was started and the reaction timer was started. The additions of catalyst and urea are shown in Tables <NUM> and <NUM>:.

<NUM> Bismuth (III) Trifluoromethanesulfonate (<NUM>% pure) was used as the catalyst for this reaction. The catalyst was added to the reactor in a semi-batch manner as shown below. <NUM> urea (<NUM>% pure) was dissolved in <NUM> deionized water to form aqueous solution. The urea solution was fed into the reactor using a syringe pump in a semi-batch manner. When the reactor temperature reached <NUM>, the additions of both catalyst and urea solution were started and the reaction timer was started. The initial syringe pump rate was set at <NUM>/min for <NUM> minutes to feed about <NUM>% of the total urea solution. Then the pump rate was reduced to <NUM>/hr to feed the rest <NUM>% solution. The total feeding time was about <NUM> hours. The rate of addition of catalyst is shown in Table <NUM>.

After the urea feeding was done, the reaction was continued to reach total reaction time of <NUM> hours. The reaction temperature is between <NUM>-<NUM>. After the reaction was complete, the heating mantle was shut down and the agitation rate was reduced to <NUM> rpm. When the reactor temperature dropped to <NUM>, the polycarbamate product was poured out from the reactor. The final product was analyzed using <NUM>C NMR. The hydroxyl conversion of the final product was <NUM>%. The byproduct levels are shown in Table <NUM>.

<NUM> PARALOID AU-608X polyol which consists of <NUM>% solid and <NUM>% solvent (xylenes) was added to the reactor, which had <NUM> mol hydroxyl functionality. <NUM> Bismuth (III) <NUM>-ethylhexanoate (<NUM>% pure) was added to the reactor. The heating mantle was started and set at <NUM>. The nitrogen sparging flow rate was set at <NUM> sccm. The reaction mixture was agitated at <NUM> rpm and then adjusted to <NUM> rpm when the reactor temperature was over <NUM>. <NUM> urea (<NUM>% pure) was used for this reaction. The urea solid was fed into the reactor using a semi-batch manner. When the reactor temperature reached <NUM>, the additions of urea were started and the reaction timer was started. The addition of urea is shown in Table <NUM>:.

<NUM> PARALOID AU-608X polyol which consists of <NUM>% solid and <NUM>% solvent (xylenes) was added to the reactor, which had <NUM> mol hydroxyl functionality. <NUM> Bismuth (III) <NUM>-ethylhexanoate (<NUM>% pure) was added to the reactor. The heating mantle was started and set at <NUM>. The nitrogen sparging flow rate was set at <NUM> sccm. The reaction mixture was agitated at <NUM> rpm and then adjusted to <NUM> rpm when the reactor temperature was over <NUM>. <NUM> urea (<NUM>% pure) was used dissolved in <NUM> deionized water to form aqueous solution. The urea solution was fed into the reactor in a semi-batch manner using a syringe pump. When the reactor temperature reached <NUM>, the additions of urea were started and the reaction timer was started. The initial urea feeding rate was set at <NUM>/min to feed <NUM>% of the urea solution. The feeding rate was then adjusted to <NUM>/hr to feed the rest <NUM>% of urea solution. The urea feeding lasted for about <NUM> hours.

Carbamylation reactions of an acrylic polyol (PARALOID AU608x) using both methyl carbamate and urea were carried out in an array of <NUM> high throughput reactors with an internal volume of <NUM> (utilizing glass tube inserts), equipped with stirring and capable of continuous nitrogen purge of the reactor head space to remove the volatile by products (ammonia gas).

A comprehensive list of compounds based on different metals and ligands was tested in this study. Experiments were carried out in sets of <NUM> in triplicates. Each set of <NUM> contained four experiments using dibutyltin oxide and two experiments with no catalyst, as control experiments. Pre-weighed glass tubes were loaded with about <NUM> of a <NUM>% solution of Au608x polyol in xylene. They 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 (urea/OH) ratio of <NUM> and hydroxyl groups and <NUM> wt% of catalyst, based on the weight of polyol; respectively. The tubes were then placed into the bottom part of the high throughput reactor. The reactor head was placed on top and clamped in order to seal the reactor. The reactor was then heated to <NUM> while being purged by nitrogen.

FT-IR was used to monitor the disappearance of hydroxyl group as a measure of the extent of each reaction. The experiments that were conducted with dibutyltin oxide, Bu<NUM>SnO, in each set of <NUM> were used as reference for comparing the efficiency of the each compound in catalyzing the carbamylation reaction, within that set. The extent of reaction in each tube, as determined by FT-IR, was divided by the average of the extent of reaction utilizing Bu<NUM>SnO in that set. This was to block the potential set-to-set variability in the experiments that might have existed.

Relative conversion data for the carbamylation experiments, including the results of the "no catalyst" reactions, are provided in Table <NUM>.

OH number is the magnitude of the hydroxyl number for a polyol as expressed in terms of milligrams potassium hydroxide per gram of polyol (mg KOH/g polyol). Hydroxyl number (OH #) indicates the concentration of hydroxyl moieties in a composition of polymers, particularly polyols. The hydroxyl number for a sample of polymers is determined by first titrating for the acid groups to obtain an acid number (mg KOH/g polyol) and secondly, acetylation with pyridine and acetic anhydride in which the result is obtained as a difference between two titrations with potassium hydroxide solution, one titration with a blank for reference and one titration with the sample. A hydroxyl number is the weight of potassium hydroxide in milligrams that will neutralize the acetic anhydride capable of combining by acetylation with one gram of a polyol plus the acid number from the acid titration in terms of the weight of potassium hydroxide in milligrams that will neutralize the acid groups in the polyol. A higher hydroxyl number indicates a higher concentration of hydroxyl moieties within a composition. A description of how to determine a hydroxyl number for a composition is well-known in the art, for example in <NPL>).

Gardner color: was measured according to ASTM D1544 "Standard Test Method for Color of Transparent Liquids (Gardner Color Scale)" using a HunterLab colorimeter.

<NUM>C NMR: All samples were characterized by <NUM>C NMR in solutions. For a typical sample preparation, <NUM> dry material was dissolved in <NUM> DMSO-d<NUM> solvent at room temperature in a glass vial. The DMSO-d<NUM> solvent contains <NUM> Cr(acac)<NUM> as a relaxation agent. The solution was then transferred to a <NUM> NMR tube for characterization. Quantitative inverse-gated <NUM>C NMR experiments were performed on a Bruker Avance <NUM> (<NUM>H frequency) NMR spectrometer equipped with a <NUM> DUAL C/H cryoprobe. All experiments were carried out without sample spinning at <NUM>. Calibrated <NUM> ° pulse was applied in the inverse-gated pulse sequence. The relaxation delay between consecutive data acquisitions is <NUM>*T<NUM>, where T<NUM> is the longest spin-lattice relaxation time of all nuclei in the measured system. The <NUM>C NMR spectra were processed with a line broadening of <NUM>, and referenced to <NUM> ppm for the DMSO-d<NUM> resonance peak.

Claim 1:
<NUM>% Solids polycarbamate comprising less than <NUM> wt% total of biuret, cyanuric acid, and polyallophanate obtainable by a process to prepare polycarbamate comprising:
adding urea to a polyol selected in the group consisting of oligomers or polymers derived from hydroxyl-containing acrylic monomeric units in the presence of at least one catalyst selected from the group consisting of: Al(III) acetylacetonate, Bismuth(III) trifluoromethanesulfonate, Bi(III) tri(<NUM>-ethylhexanoate), wherein the process achieves at least a <NUM>% conversion of hydroxyl groups of the polyol.