Water-based polyurethane coating formulation and process steps

China Coatings Online News
1, modified trimer crosslinker products can be manufactured by isocyanates such as TDI, IPDI, MD I and XDI. Its aromatic NCO reaction temperature is at (120-150) degrees C, and the fat NCO reaction temperature is at (150-200) degrees C. Its greatest advantage is no yellowing, transparent water white, more suitable for water-based polyurethanes such as pyridine-type ambient crosslinker. In order to enhance the comprehensive performance, two NCO group activity is different isocyanate, and the end NCO produced in the reaction should be multi-alcohol-pyridine reaction, in order to promote amine neutrality and the water solubility of the product. Due to its high melting point, the reaction needs to be carried out in stages in organic solvents, organic pyrethroide catalyst and temperature above 120 degrees C, isocyanate can occur a self-shrinking reaction, the generation of trimer compounds. The catalyst in the hexacyctic hydrogen is the most effective, the reaction temperature is low, the yield can reach 90 %, and then the triple catalysis method is used to promote the reaction completely, and the residual base is closed.product formulation: NCO: polyol pyriclic acid (the ratio of substances) is 6:1:1.43.process steps: polyol-carpic acid solution preparation, according to the formula will be new glycol, benzodiaxyl, DMPA, xylene, toluene into the reactor stirring, heating up to 80 degrees C, after the completion of dissolution, heating up to 148 degrees C reflow dehydration to transparent, filter out the material backup. Preparation of absamine prejudes: according to the formula to add xylene, toluene into the reactor, heating up to 148 degrees C reflow dehydration, add 10 % phosphoric acid (toluene) liquid cooling to 120 degrees C, into nitrogen, TD I, IPDI added to the monomer drip kettle, in 2 . After 5h has completed the drip addition, heat up to 130 degrees C reaction 1h, add 10 % of the hexacyclyceride hydrogen to the drip kettle, start slowly add, constantly observe the material reaction, Prevents detonation, drops at 130 degrees C reaction 2h, 140 degrees C 1h, 145 degrees C 30min, cools down to 70 degrees C, and cools polyol-phosphate Add the drip kettle to start dripping, drop at 70 degrees C reaction (2-3) h, detect the NCO conversion rate of 96 %, add 10 % lithium acetate, there are two processes: one is to cool down to 25 degrees C, sit 7d; The second is to heat up to (80-90) reaction (2-3) h, free TD I at 0.3% below, add 10 % toluene sulfonate liquid, 10 % methamphetamine liquid heat up to 85 degrees C reaction 20min, vacuum out of 2/3 amount of organic solvent, Then add hydrophobic solvent regulation solid content of 50 %, cool down to 50 degrees C add 50 % triethylamine aqueous solution, N-toluene ethanolamine regulation p H value to 8.5, heat up to 60 degrees C reaction to transparent, cool down to 40 degrees C out of the material.
。