Preparation And Properties Study Of Flame Retardant Air Filter Paper

Air filter paper is the core component of the air filter of automobile engine.As a flammable material,in practical application,the filter paper may burn due to engine"tempering"or inhalation of high-temperature particles with sparks,which would lead to auto-ignition and cause severe accident.Therefore,air filter paper must present excellent flame retardant property from the perspective of safety.At present,domestic flame retardant air filter paper products can not meet the practical application demand due to their poor comprehensive performances,flame retardant air filter paper products with excellent performances mainly rely on imports.In this paper,we designed and synthesized the strengthen resin with excellent flame-retardant property,combining with pristine air filter paper with MF fiber endow the air filter paper product with excellent flame-retardant property and comprehensive properties.The main research contents of this paper are as follows:?1?Firstly,Epoxide phosphate?EPPA?was prepared by ring-opening condensation reaction of Bisphenol A epoxy resin?E-51?with phosphoric acid.The effects of reaction technology,diluent dosage,material ratio and reaction temperature on the condensation reaction process and product composition were studied.The results showed that the optimun preparation process was as follows:the mass ratio of epoxy resin to diluent was 2.0:1.0,The molar ratio of E-51:H₃PO₄ is 1.05:2.00.The reaction condition was 40?for 3h,then raised to 60?for 1h,and 70?for 1h.FTIR,31P NMR and APC results showed that prepared the epoxide phosphoric acid system were mainly the target product.?2?Secondly,EPPA modified polyacrylic resin?EPPA-PA?was prepared by radical graft copolymerization.Effects of polymerization process and EPPA content on the polymerization and the graft rate of EPPA were studied.The thermal,flame retardant and coating properties of EPPA-PA resin cured by MF resin were analyzed and tested.Finally,EPPA-PA emulsion was prepared by self-emulsifying method.The results showed that the grafting rate of EPPA decreased with the increase of EPPA dosage.The grafting rate of EPPA reached the maximum when the amount of system initiator was 1.5wt%and the reaction temperature was 75?.FTIR result shows that the ungrafted EPPA can also cross-link with the curing agent MF resin,the cured EPPA-PA resin presents excellent coating properties.The flame retardant property of EPPA-PA resin system increases with the increase of phosphorus and nitrogen content of the resin system.When the phosphorus?P?and nitrogen?N?content of the resin system reaches1.70wt%and 5.30wt%,respectively,the LOI of the resin system can reach 26.3%,and can pass the V0 test of UL-94.In addition,when the MAA dosage of the EPPA-PA system is 5wt%and neutralized by ammonia?neutralization degree is 100%?,stable EPPA-PA resin emulsion can be formed under shear force by a self-emulsifying method.?3?HPN monomer,E-51,acrylic monomer and urea were used as raw materials to prepare P and N modified epoxy acrylic resin?HPN-EPPA-UR-PA?by means of radical solution polymerization and graft polymerization simultaneously.The molecular structure,thermal properties,flame retardant properties and thermal decomposition kinetics of the resin system were characterized by FTIR,TG-IR,SEM and CONE respectively.Finally,the prepared HPN-EPPA-UR-PA is applied to prepared flame retardant air filter paper.The results showed that the flame retardant property of the resin increases with the increase of P content,while the flame retardant property of the resin increased first and then decreased with the increase of N content.Meanwhile,non-flammable gases such as CO₂,NH₃and water vapor are produced when the resin is decomposed by heat.When HPN monomer content was 50wt%and urea content was5wt%,the resin presents best flame retardant property.Besides,the activation energy of thermal decomposition of the resin increased continuously,showing the synergistic effect of phosphorus and nitrogen.The enhanced filter paper could pass the flame retardant standard test of filter paper?GB/T 14656-2009?when the P and N content of the HPN-EPPA-UR-PA resin system was 6.45wt%and 2.33wt%,respectively.?4?Finally,the feasibility of MF fiber as a fiber material for air filter paper was demonstrated in detail.MF fiber was mixed with cellulose fiber to prepare pristine air filter paper,then flame-retardant air filter paper was prepared by reinforcing with the HPN-EPPA-UR-PA emulsion.Effects of MF fiber content,P content of emulsion and resin content on mechanical properties and flame retardant properties of filter paper were studied in detail.The results showed that MF fiber can be used as a fiber material for preparing pristine air filter paper.When the HPN-EPPA-UR-PA?with P and N content are 5.16wt%and 2.33wt%,respectively?resin system content is 25wt%,and the MF fiber content is 20wt%,The prepared flame retardant air filter paper present excellent mechanical properties and pass the GB/T 14656-2009 test and therefore has the potential for practical application.