Patent Application
20070270565
All percentages are by weight unless noted otherwise.
The NCO content of the resins described in the inventive and comparative examples was determined by titration in accordance with DIN 53 185.
The dynamic viscosities of the polyisocyanate resins were determined at 23° C. using the VT 550 viscometer with the PK 100 plate-cone measurement arrangement from Haake (Karlsruhe, Germany). Measurements at different shear rates ensure that the rheology of the inventive polyisocyanate mixtures described and also that of the comparison products corresponds to that of ideal Newtonian liquids. It is therefore unnecessary to state the shear rate.
The selectivity of the catalyst employed was determined by 13C NMR spectroscopy and by analysis of the possible structural types 1 to 4.
For this 13C NMR analysis, 0.5 ml of the respective reaction mixture was admixed with amounts of di-n-butyl phosphate that were stoichiometric with respect to the amounts of catalyst employed, this admixture being made in order to deactivate the catalyst and to prevent further reaction. Deuterated chloroform was added to set a concentration of approximately 50% by weight of resin. The measurements were made on a DPX 400 from Bruker, Karlsruhe, DE with a 13C resonance frequency of 100 MHz. As a reference for the ppm scale, tetramethylsilane was used as internal standard. Data for the chemical shift of the compounds I-4 in question were taken from the literature (cf. Die Angewandte Makromolekulare Chemie 1986, 141, 173-183 and references cited therein) or had been obtained by subjecting model substances to measurement.
13.0 g of 4-aminopyridine (0.138 mol), 19.1 ml of triethylamine (14.0 g, 0.138 mol) and 0.1 g of diazabicyclooctane (DABCO) were dissolved in 100 ml of dimethylformamide. Added dropwise to this solution at room temperature over the course of 15 minutes were 14.6 ml of trifluoromethanesulphonyl chloride (23.3 g, 0.138 mol). After the addition the temperature of the reaction mixture rose to 35° C. After the reaction mixture had been cooled to room temperature and stirred at this temperature for 17 h, the reaction mixture was discharged into 250 ml of water with stirring. The precipitated crude product was isolated by suction filtration and washed with three times 100 ml of water. Thereafter the crude product was dried at 100° C.
The dried crude product (18.9 g) was recrystallized from acetonitrile. This gave 14.5 g of clean product, whose structure was ascertained by mass spectrometry.
A suspension of 5.2 g of the sulphonamide of Example 1 (23.2 mmol) in 13 ml of methanol was admixed at room temperature with 5.3 ml of a 30% strength by weight sodium methoxide solution in methanol (23.2 mmol). After 1 h of stirring at room temperature, 10.5 g of a 71.4% strength solution of tetrabutylammonium chloride in isopropanol (23.2 mmol) was added to the reaction mixture, which was stirred at room temperature for one hour further. The precipitated sodium chloride was filtered off with suction and the filtrate was concentrated to dryness by distillation. By addition three times of 10 ml in each case of methylene chloride, stirring of the catalyst in this solvent and distillative removal of the solvent, the catalyst was freed from residues of isopropanol. Drying at room temperature in vacuo gave 8.0 g of solid catalyst.
Inventive dimerization of hexamethylene 1,6-diisocyanate (HDI) with the catalyst of Example 2.
250 ml of hexamethylene 1,6-diisocyanate (260 g, 1.548 mol) were heated to 100° C. in a four-necked flask filled with dry nitrogen and carrying a reflux condenser. At the temperature of 100° C., 0.29 g of the catalyst of Example 2 (0.6 mmol) was added and the mixture was stirred at 100° C. for 7 h. The reaction mixture was subsequently adjusted to 80° C., admixed with 0.52 g of di-n-butyl phosphate (2.5 mmol) and stirred at 80° C. for 2 h. Then 242 g of the reaction mixture were worked up by means of a thin-film evaporator. The mixture was distilled at 120° C. under a pressure of 0.8 mbar to give 30.7 g of a uretdione-containing resin.
On the basis of the 13C NMR spectrum recorded the product was free from trimeric structures of the general formula 2 and 3. The desired uretdione of the structure of the general formula 1 is contaminated only slightly by biuret of the general formula 4, which forms as a result of traces of water being present.
Inventive dimerization of hexamethylene 1,6-diisocyanate (HDI) with the catalyst of Example 2.
300 ml of hexamethylene 1,6-diisocyanate (312 g, 1.548 mol) were heated to 100° C. in a four-necked flask filled with dry nitrogen and carrying a reflux condenser. At the temperature of 100° C., 0.35 g of the catalyst of Example 2 (0.6 mmol) was added in solution in 1 ml of n-butanol and the mixture was stirred at 100° C. for 4 h. The reaction mixture was subsequently admixed with 0.31 g of di-n-butyl phosphate (0.7 mmol) and stirred at 100° C. for 2 h. Then 298 g of the reaction mixture were worked up by means of a thin-film evaporator. The mixture was distilled at 120° C. under a pressure of 1.0 mbar to give 25.8 g of a uretdione-containing resin.
On the basis of the 13C NMR spectrum recorded the product was free from trimeric structures of the general formula 2 and 3. The desired uretdione of the structure of the general formula 1 is contaminated only slightly by biuret of the general formula 4, which forms as a result of traces of water being present.
5.0 g of 4-aminopyridine (0.053 mol) were introduced in 52 ml of tetrahydrofuran as an initial charge at 50° C. At this temperature 7.4 ml of triethylamine (5.4 g, 0.053 mol) and 0.1 g of diazabicyclooctane (DABCO) were added to the reaction mixture. This solution was admixed dropwise at 50° C. over the course of 15 minutes with 9.5 ml of perfluorobutanesulphonyl fluoride (16.0 g, 0.053 mol). A slight exothermic reaction was observed. Stirring was continued at 55° C. for 11 h, after which the solvent was distilled off. The oil obtained was discharged into 200 ml of water with stirring. The precipitated crude product was isolated by filtration with suction.
The still slightly moist crude product (20.2 g) was recrystallized from acetonitrile. This gave 9.2 g of clean product, whose structure was ascertained by mass spectrometry.
A suspension of 3.9 g of the sulphonamide of Example 1 (10.5 mmol) in 25 ml of methanol was admixed at room temperature with 2.0 ml of a 30% strength by weight sodium methoxide solution in methanol (10.5 mmol). After 1 h of stirring at room temperature, 4.7 g of a 61.4% strength solution of tetrabutylammonium chloride in isopropanol (10.5 mmol) was added to the reaction mixture, which was stirred at room temperature for one hour further. The precipitated sodium chloride was filtered off with suction and the filtrate was concentrated to dryness by distillation. This gave 4.6 g of catalyst of oily consistency.
Inventive dimerization of hexamethylene 1,6-diisocyanate (HDI) with the catalyst of Example 5.
Under nitrogen, a glass vessel with septum was charged with 0.4 g of catalyst (0.6 mmol). 10 ml of hexamethylene 1,6-diisocyanate (10.4 g, 61.9 mmol) were added and the reaction solution was stirred at 80° C. for 22 h until its NCO value had dropped to 36.7% by weight. According to 13C NMR spectroscopy the reaction mixture, in terms of isocyanate derivatives, contained a mixture of 98 mol % of uretdione of structure 1 and 2 mol % of trimer of structure 2.
Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102006023262.3 | May 2006 | DE | national |
