Preparation and properties of flame retardant microfiber synthetic leather base

To solve the problem of poor stability of additive flame retardant waterborne polyurethane， a series of waterborne polyurethane with flame retardant properties was synthesized by prepolymer method using aliphatic polyisocyanate， polyether polyol， and flame retardant phosphorus-containing polyol as raw materials. The flame retardant waterborne polyurethane was applied to the dipping process of microfiber synthetic leather base （microfiber base）. Its effects on the mechanics， quality， flame retardant， and thermal decomposition properties of microfiber base were discussed. The results show that with the increase of phosphorus-containing flame retardant polyol content， the combustion rate decreases from 115.00 mm/min to 60.79 mm/min， and the limiting oxygen index increases from 21.00% to 24.20%. After different concentrations of phosphorus-nitrogen flame retardants were sprayed on the surface of microfiber base， microfiber base appears self-extinguishing phenomenon during combustion， and the limiting oxygen index increases to 27.00%. Compared with the microfiber base without flame retardant treatment，the peak heat release rate and total heat release rate of the microfiber base after flame retardant treatment are reduced by 42.29% and 20.01%， respectively. The test analyses of SEM and Raman spectroscopy reveal that the graphitization degree of the carbon layer is improved and the surface structure becomes more compact after flame retardant finishing， suggesting that the flame retardant plays a crucial role by using the condensed phase flame retardant mechanism.