Studies On Spontaneous Ignition Mechanism And Flame Retardant Modification Of Alkyd Resion Paint

Alkyd resin is widely used because of its advantages of simple manufacturingprocess and good performances. However, during the spraying process, a lot ofcoatings become waste, which will dry to the solid waste. During the drying processspontaneous combustion often occurs, resulting in fire hazards. To solve thespontaneous ignition problem, the spontaneous ignition mechanism and the flameretarding of alkyd resin were studied.For the spontaneous ignition mechanism, the infrared spectroscopy was used toanalyze the variations of chemical bonds during the curing process of alkyd resin and itwas found that the C=C bond in the uncuring resin changed into the C-C, C=O, andperoxide bonds in the curing resin. Thermodynamics analysis showed that thevariations of chemical bonds were exothermic. Further, through measuring the heat ofcombustion of alkyd resin before and after curing, the heat of curing was obtained.Based on the data of heat of curing for the alkyd resin containing different content ofC=C, it was found that the heat of curing increased linealy with the content of C=C. Inaddtion, the spontaneous ignition model analysis indicated that the heat of curingwould lead to the ignition of the alkyd resin waste, implying that the spontaneousigniton should be ascribed to the heat of curing.For the flame retardant of alkyd resin, physical and chemical methods were used.The physical methods added the traditional intumescent flame retardant, the flameretardant PMPP synthesized from phosphoric acid, pentaerythritol and melamine, theflame retardant PPMPP synthesized from polyphosphoric acids, pentaerythritol andmelamine respectively into the alkyd resin. The chemical methods tried to introducethe pentaerythritol phosphate and the phosphoric acid respectively into the chemicalchain of alkyd resin. The fire test results showed that the PPMPP had advantages over other methods in increasing the flame retardancy of alkyd resin due to its high charringresidue of30%after decomposition. If the mass fraction of PPMPP was30%, theignition time of the alkyd resin specimen in the cone calorimeter test at50kW/m2heatflux was delayed from7s to15s. The peak heat release rate decreased from1888.1kW/m2to141.5kW/m2，and the total heat release decreased from133.2MJ/m2to42.8MJ/m2. Further the addition of PPMPP reduced the smoke production of the alkydresin.