Preparation Of Flame-retardant Acrylic Waterproof Coating And Its Properties Research

Acrylic waterproof coating has good water resistance and flexibility,and the formed acrylic coating film has the characteristics of high strength,strong adaptability to base layer shrinkage and deformation cracking,and good low temperature bending performance.However,with the development of economy and society,coatings with a single function can no longer meet the needs of use.Therefore,the flame retardant is added to give the coating a flame retardant function.At present,the general flame retardant is easy to absorb water,which is not suitable for waterproof materials.Therefore,it is necessary to modify the flame retardant to ensure the flame retardant and improve the water resistance.In this paper,acrylic emulsion was used as the film-forming substrate,and various flame retardants such as melamine phosphate(MPP),triazine carbon forming agent(CFA),and pentaerythritol phosphate(PEPA)were used to prepare flame-retardant acrylic waterproof coating.The contents of this paper are as follows:(1)Melamine phosphate(MPP)and triazine carbon forming agent(CFA)are choose as flame retardant system and add them to acrylic emulsion to prepare coating.The effects of MPP/CFA systems on properties are studied.The results show that:acrylic coating without flame retardant is flammable,the limiting oxygen index is 22%,With the addition of 1 wt.%MPP and 4 wt.%CFA,the limiting oxygen index of the coating is 25%,and the time for the flame height reach 150 mm in the combustion test was extended from 46 s to 150 s.After immersion in water for 168 hours,the tensile strength retention of the coating is>80%,the elongation at break is>140%,and the water absorption is<20%.The coating has excellent water resistance.By XPS analysis of the composition and element content of the residual carbon,it was found that the flame-retardant waterproof coating contains more element contents of P and N,indicating that MPP/CFA plays a flame-retardant role in both the gas phase and the solid phase.In addition,GO was added to the MPP/CFA system as a carbon source,the cone calorimetry test showed that when MPP,CFA,and GO were added at 1 wt.%,4 wt.%,and 0.005 wt.%,respectively,the pHRR of the coating decrease from 343.54kW/m2 to 292.43 kW/m2,tHRR was delayed from 35 s to 50 s.The water absorption of the coating decreased from 11.3%to 9.1%.(2)Surface modification of pentaerythritol phosphate by silane coupling agent to obtain KH550-PEPA,and then KH550-PEPA was added to the coating,results showed that:with the addition of 5 wt.%KH550-PEPA,the tensile strength of the waterproof coating was increased from 0.3 MPa to 1.1 MPa.After immersion in water for 168 hours,the water absorption rate of the coating decreased from 8.83%to 7%.The mass change rate decreased from 8.8%to 6.8%,both the mechanical properties and water resistance of the coating have improved.With the addition of 4 wt.%KH550-PEPA and 1 wt.%MPP,the water absorption rate of the coating decreases to 6%.(3)By ion exchange reaction,a new type of phosphorus nitrogen flame retardant melamine tripolyphosphate(STTP-MEL)was synthesized from sodium tripolyphosphate(STTP)and melamine(MEL),then STTP-MEL was added to acrylic emulsion to prepare coating.The results show that:with the addition of 10%STTP-MEL the LOI of coating increases from 22%to 27%,the total heat release of the coating decreases by 38.4%,the total smoke release decreases by 27.7%,both the morphology and the amount of carbon residue have improved.Analysis of the flame retardant mechanism of the coating shows that STTP-MEL plays a flame retardant role both the gas phase and the solid phase,respectively.At the same time,the coating has excellent water resistance,with the addition of 10%STTP-MEL,the water absorption rate of the coating decreased from 11.8%to 7.4%and the quality change rate was 3%.