Study On Synthesis Of Low Free Formaldehyde Phenolic Resin And Foam Properties

The current building energy consumption accounts for1/3of the total energyconsumption in china. Heating urban residential area in northern China accounted foronly10%of the urban residential area, but they accounted for40%of building energyconsumption.Our biggest building energy consumption in the use of heating andcooling is compared with similar climatic conditions in developed countries, China’sbuilding heating energy consumption per square meter is about three times thedeveloped countries.In response to the national energy saving requirements, a large amount of foam isused for building insulation. Inorganic insulation materials hold the feature ofrefractory, but high thermal conductivity. The need to achieve a certain effect of theinsulation material thickness, and therefore a large load on the wall.The widely usedorganic insulation materials such as polyurethane, polystyrene lightweight butflammable, lead to repeated fire. Flame and low thermal conductivity of phenolicfoam emerged.In this paper, phenolic resin synthesis conditions and factors affecting theperformance of phenolic foam were studied. Paraformaldehyde replace liquidformaldehyde solution was used to one-pot synthesis of phenolic resin. Because theresin solids content reach to85%to88%, so no post-processing need to be used toprepare the foam product,thus avoiding the "waste" emissions. The molar ratio of F/P,synthesis temperature, synthesis time, amount of catalyst performance phenolic resinwere studied.The results showed that:1%sodium hydroxide as a catalyst is moresuitable for industrialized production and to obtain a low free formaldehyde contentof the resin. The lower of F/P and the lower content free formaldehyde. Higertemperatures and longer time for the resin can enhance the viscosity of the reaction.The use of urea resin can effectively reduce the content of free formaldehyde.The effect of blowing agents, surfactants, curing agents, viscosity of the resin andsolid content of phenolic foam foaming conditions were investgated. The results showthat: the viscosity of the resin should be controlled between6000to20000mpa.s, thereaction temperature should be controlled at about60℃, The appropriate initial temperature of liquid should be controlled between20℃to30℃, a moderate densityproducts can be obtained by use6%of blowing agent,5%to6%of surfactant canplay better emulsifying and foam stabilizing effect, with the enhancement of curingagent, the foam density, tensile strength, water absorption and thermal conductivityare upgrading to improve, sulfuric acid as a curing agent to obtain a foam appears to asmaller diameter than organic acid but easy to crack, foam properties can be adjustedthrough an appropriate amount of curing agent according to user needs. Ethyleneglycol, dipropylene glycol, polyether330can improve the tensile strength of phenolicfoam.