Preparation Of P-N-Si-B Flame Retardant And Application In Air Filter Paper

The booming of the air filter industry places higher demands on the performance of air filter paper.In addition to the excellent filtration performance of the purified air,as well as the mechanical properties and processing properties of the filter paper,higher requirements are placed on its flame retardant properties.Therefore,the structural design and performance requirements of the reinforced resin used in air filter paper become the key to such filter materials.At present,air filter paper is reinforced with styrene-acrylic emulsion,which has insufficient water resistance,long service life,especially in coastal hot and humid environment,and the urethane-acrylic emulsion-enhanced air filter paper is mostly made of plant fiber,which cannot solve the increasingly important resistance.Safety issues such as fire and fire.Therefore,this paper designs and prepares a series of P,N,Si,B synergistic flame retardant flame retardant from the raw material ammonium polyphosphate?APP?,and introduces flexible structures such as organosiloxane and polyether,and finally with styrene-acrylic emulsion to prepare air filter paper with excellent comprehensive performance.First of all,APP is a modern halogen-free green flame retardant that has been widely used in all aspects of daily life.However,due to its certain water absorption,in the application of fiber or paper,fiber or paper may have a certain moisture absorption and moisture absorption phenomenon after adding APP.Therefore,hydrophobic modification of APP is an important research topic at this stage.The nano-scale SiO₂ was coated on the surface of APP by sol-gel method.On the basis of this,the in-situ reaction was carried out on the surface of the particles by hydrosilylation,and further microcapsule coating was carried out to introduce different polyether side chains.The reaction temperature,reaction time,catalyst amount,molar ratio of unsaturated bond to silicon hydrogen bond,and mass ratio of inner and outer coating were fully investigated.The optimum preparation conditions were confirmed:temperature was 85°C,time was 1.5 hr,catalyst content It is 30 ug/g?in terms of the amount of platinum based on the total mass of the reactants?.The structure of the modified APP was characterized by infrared spectroscopy?FT-IR?.The surface contact angle was used to characterize the hydrophilic properties of the modified APP.The results showed that the hydrophobicity of the modified APP was improved.The contact angle was from the original19.9.°increased to 41.2°.Particle size analysis was used to characterize the particle size and distribution of modified APP.TGA analysis showed that the decomposition rate of the modified APP by double coating decreased from 20%of raw material APP to 7 The residual carbon rate at 800°C is also increased from 21.73%of the raw material APP to 50%or more.The TGA analysis fully demonstrates that the heat resistance and flame retardancy of the modified APP are improved.The stability of the blended resin was confirmed by delamination by centrifugation and high temperature environment.In order to further improve the compatibility of the particles with the emulsion and the flame retardancy of the material,the B element is further introduced on the basis of the above particles.The structure was confirmed by FT-IR analysis.It was found by particle size analysis that when B element was introduced,the particle size became smaller and the distribution was more uniform than that of the corresponding non-B element.The capacitance is greatly improved;the surface morphology is analyzed by scanning electron microscopy,and the secondary coated modified APP forms a micron-nano size with an average thickness of 4.01?m similar to the surface texture of the lotus leaf on the basis of the raw material APP.The coating layer changed the surface morphology and roughness of APP.TGA analysis showed that the decomposition rate of modified APP which was coated by B element again decreased from 20%of raw material APP to 5.2%,the maximum quality.The loss was reduced from 60.71%of the raw material APP to 21.31%.The carbon residue rate at 800°C was also increased from 21.73%of the raw material APP to more than 50%,which fully demonstrates the heat resistance and flame retardancy of the modified APP after the introduction of the B element.The stability of the resin was confirmed by delamination again by centrifugation and high temperature environment.Based on the above research,selected five modified APP systems with good stability and styrene-acrylic emulsion compounding,and investigated the blending system of self-made modified APP and styrene-acrylic emulsion for enhancing the performance of air filter paper,and studied Water resistance,flame retardancy and mechanical properties of air filter paper.The structure of the blended system was characterized by infrared spectroscopy?FT-IR?.The particle size and distribution of the blended resin system were characterized by particle size analysis.The TGA analysis showed that by adding the modified styrene-acrylic emulsion resin,The decomposition rate is reduced from 60%of pure styrene-acrylic emulsion to about27%,and the residual carbon rate at 800°C is also increased from 0.23%of raw material APP to over 30%,which fully demonstrates that the heat resistance and flame retardancy of the reinforced resin are obtained.improve.The morphological analysis of the resin before and after combustion was observed by scanning electron microscopy to determine the flame retardant mechanism.The synergistic effect of the two mechanisms of condensed phase flame retardant and gas phase flame retardant was determined.When the resin was reinforced by the compound resin,the bursting resistance and tensile resistance of the air filter paper were observed.The strength,elongation at break,stiffness and fracture work are greatly improved compared with the original filter paper.The bursting resistance and elongation at break are higher than those of pure styrene-acrylic emulsion,from 371kPa and 4.89%to 440kPa and8.89%,increased by 18.6%and 81.8%respectively;through the cone calorimeter combustion test analysis,compared with pure styrene-acrylic emulsion enhanced filter paper,the HRR,THR and TTI indexes of the compound resin-reinforced filter paper were improved,indicating that it is flame retardancy has been greatly improved.