3 lines
2.1 KiB
JSON
3 lines
2.1 KiB
JSON
{
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"protocol": "Combine a silicone compound having a hydrophilic functional group with a water dispersible polyurethane compound. The silicone polymer or oligomer should be present in the formulation at about 0.1 to about 20 parts by weight, preferably about 1 to about 10 parts by weight, and more preferably about 1 to about 5 parts by weight. The water dispersible polyurethane polymer or oligomer should be included at about 5 to about 50 parts by weight, preferably about 10 to about 40 parts by weight, and more preferably about 20 to about 30 parts by weight. The remainder of the formulation should be an aqueous solvent, primarily water, with the optional addition of a co-solvent at about 1 to about 10 parts by weight, preferably about 5 to 10 parts by weight. The total weight of the compounds in the formulation should sum to 100 parts by weight. Functional groups may include —CO2H, —OH, —NH, —SH, ester, urethane, and isocyanate groups, but should exclude strong acids such as sulfonic acid functional groups. The silicone polymer or oligomer is to be carefully selected to maintain film integrity and prevent degradation.The synthesis of hydrophilic polymers with functional groups involves the following steps: Charge polypropylene glycol diol, dimethylol propionic acid (dissolved in percentage of N-methyl-pyrrolidinone), and dibutyltin dilaurate into a reactor under a nitrogen environment at approximately 80°C. Slowly add hydrogenated diphenyl methane diisocyanate to the reactor, maintaining the reaction for 3 hours until the theoretical NCO% is reached. Cool the reaction mixture to 60°C, then add triethylamine to neutralize the acid functionalities. Introduce water with vigorous agitation to form the dispersion, followed by adding a solution of diethylene triamine in N-methyl-pyrrolidinone and water to complete chain extension, continuing the reaction for an additional 2 hours. The resulting polyurethane dispersion should have a solids content of about 35 to 40 weight percent. Apply the dispersion to a substrate and dry at elevated temperature to achieve a crosslinked film."
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