Preparation And Research Of Water-borne Ultra-thin Fire Retardant Coating For Steel Structure

As a rapidly developing building structure,steel structure has the characteristics of light weight,high strength,easy construction and recycling.It has been widely applied in the field of architecture.Steel structure also has obvious shortcomings,steel itself does not burn,but as a metal its thermal conductivity is very good,in the event of a fire,only more than 10 minutes will reach the critical temperature of steel itself,steel endurance sharply weakened,causing building collapse and economic losses.Therefore,it is necessary to improve the refractory limit of steel and to protect it effectively.The improvement of steel fire resistance is usually coated with a fireproof coating on the steel surface,which can effectively improve the refractory limit of steel.This paper mainly studies the influence of various components of waterborne ultrathin fire retardant coatings on the performance of coatings.The first is the choice of the type and dosage of the base emulsion.Four kinds of emulsion,pure acrylic emulsion,silicone acrylic emulsion,styrene acrylic emulsion and EVA emulsion,were used to study the fire resistance and determine its dosage.Then,the effect of the distribution of APP,MEL and PER on the properties of the coatings was investigated by orthogonal test,the optimum proportion of ammonium polyphosphate,melamine and Pentaerythritol was 5:3:3.Finally,the influence of the addition of inorganic fillers on the properties of the coatings was investigated.The main selection of zinc stannate,aluminum hydroxide,expanded graphite,boric acid and titanium dioxide as the research object,through the test of fire resistance,aluminum hydroxide as filler,reach the best fire resistance,to 65 min.In addition,the effect of composite use of boric acid and aluminum hydroxide on the performance of coatings was studied,and the formula of the final fire retardant coating was determined.In this paper,the synthesis conditions of melamine phosphate are optimized by using concentrated phosphoric acid and melamine as a direct synthesis of melamine phosphate instead of ammonium polyphosphate and melamine,and the optimum reaction conditions are: 250 mL solvent,phosphoric acid: MLE= 1.1:1,120 °C reaction 3 h.The melamine phosphate synthesized by this condition is used to prepare fire retardant coatings and to study its fire resistance.The results show that the emulsion has the best effect of EVA and the refractory time is 35 min,which conforms to the use standard.In addition,the paper also use of 3.22 M sodium silicate to prepare fire retardant coatings,the impact of various additives on fire resistance,water resistance performance.The results show that the composite use of silica sol and silicone acrylate emulsion improves the performance of fire retardant coatings,the water resistance reaches more than 24 h,and the refractory limit time is greater than 50min.