Crosslinking composition
A technology of cross-linking compositions and mixtures, applied in the direction of coating, etc., can solve the problems of non-disclosure and disclosure
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Embodiment 1
[0102] Preparation of Glycoluril-Urethane Aldehyde Resin
[0103] In a suitable flask at room temperature put 1.5 g of Na 2 CO 3 and 139 grams of water. To this well stirred solution was added 150 grams of 50% glutaraldehyde in water. Cooling in an ice bath, lowering the temperature and maintaining it at about 25°C, 72.5 grams of propionaldehyde and then 35.5 grams of glycoluril were added with stirring. The temperature was then raised to about 35°C and maintained at this temperature until the solution became clear. Then about 30 grams of urea was added and reacted for about 0.5 hours.
[0104] Afterwards, 2.5 g of 97% H 2 SO 4 250 g of anhydrous MeOH, and the temperature was maintained at 25 °C (ice bath) for about 1 hour. Then, the reaction mixture was neutralized with 50% NaOH to pH 8-8.2. The reaction mixture was stripped under good vacuum at about 40-50°C to remove all MeOH and as much water as possible. After stripping, about 36 grams of propionaldehyde was adde...
Embodiment 2
[0107] Coating composition containing glycoluril-urethane aldehyde resin
[0108] A coating formulation was prepared using the crosslinked resin of Example 1 by adding 3.0 grams of Dynotol T-49emp alkyd backbone resin (85% solids in alcohol) to 3.0 grams of the crosslinked resin of Example 1, 0.3 grams of CYCAT 4040 catalyst (40.0% p-toluenesulfonic acid monohydrate in isopropanol) and 1.0 g of acetone solvent. The formulation was applied as a film about 2 mils thick on cold rolled steel panels treated with iron phosphate using a wire wound cator (#52). The panels were then allowed to cure for 7 days at room temperature (23-25°C). The film is colorfast and has a solvent resistance of greater than 100 double wipes to methyl ethyl ketone (MEK). A control plate without the crosslinked resin containing Dynotol T-49emp plus 0.3 grams of CYCAT 4040 catalyst and 1.0 grams of acetone solvent had a solvent resistance of less than 3 MEK double rubs and was yellowish.
Embodiment 3
[0109] Example 3. Preparation of melamine-urethane aldehyde resin
[0110] Into a suitable flask put 35 g of water and 0.50 g of K 2 CO 3 . The resulting solution was heated to 40°C, and 30.0 g of urea was added and stirred thoroughly to dissolve. To this reaction mixture was added 12.6 g of melamine with good stirring. To this slurry was slowly added 40.6 grams of propionaldehyde, keeping the temperature below 55-57°C. After the addition was complete, the reaction mixture was refluxed for 1 hour, cooled to room temperature and 30.0 g of 50% glutaraldehyde was added. After stirring at room temperature (22-25°C) for several hours, the reaction mixture became homogeneous, and 135 g of anhydrous methanol was added, and 5.5 g of 70% HNO 3 Adjust the pH to 4.3. The batch was allowed to react at room temperature for about 1 hour, adjusting the pH to 8.1 with 5.5 grams of 50% NaOH. The batch was then stripped under high vacuum at about 40-50°C to remove excess methanol and onl...
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