Study On The Phenolic Resin Synthesized By Paraformaldehyde And Foaming Process

Energy saving and environmental protection is the theme of today's society, and building insulation material is the hot research area for scholars, the phenolic insulation foam is made use of the thermosetting phenolic resin which is cured and foamed, this foam has a low thermal conductivity, excellent resistance to fiery, low smoke by fired, good dimensional stability and other characteristics,better than the polyurethane, polystyrene, polyethylene foam,which has occupied much market. It has been limited to large-scale production applications for that it is brittle, and easy to chalk and slag.In this paper, phenolic resin used for making foam is synthesized by paraformaldehyde and phenol and the synthesis process is optimized. The better performance of the foam insulation is based on this raw material, adding a stable foam, foaming agents, curing agents and toughener, Optimizing the proportion of each component and foaming process.The effect of the reaction temperature, the catalytic plus the amount of reaction time and other experimental conditions to the resin performance is studied in the synthesis experiments. The change of the resin viscosity is tested using the viscosity Determination, the solid content is tested using the weighing method, the resin activity is tested by mixed acid at room temperature, the changes in the structure of resin is monitored by FTIR, and the resin gel time is also tested using tablet knife method. The experimental results shows that the resin activity is the best with1%(to phenol) catalyst NaOH, and extending reaction time and increasing reaction temperature make the solid content and viscosity of the resin increased and more obvious changes occurred in later reaction. Resin viscosity is5000mpa· s-8000mpa· s with reaction time120～180min at85℃. Hydroxymethyl index increased (up to1.45) and then decreased and maintained at a certain range (around1.2), The reaction more than300min, hydroxymethyl index, and the gel time decreased significantly.Resin viscosity reduce with temperature increases,and performances exponential growth with temperature less than25℃.The performance of resin changed little, the large viscosity of the resin changes slightly with the resin placing at room temperature for one week.Foam curing time, water absorption, vertical tensile strength, density and apparent Quality were studied using the different viscosity resin, foam stabilizing agent, foaming agent, curing agents and additives at synthesis of Phenolic foam.The results show that: The resin viscosity in the5000-8000mpa· s at room temperature avail for foam performance. Foam stabilizer DC-193:EL-40=3:1, at the total of2-5%, blowing agent which has a boiling range of petroleum ether (30～60℃), at the amount of5-6%, sulfonic acid curing agent: p-toluenesulfonic acid=3:1, at the amount of3-5%benefit for the performance of the Phenolic foam with the volume density for50-60Kg/m3foam, water absorption of6-8%, the compression strength of0.18～0.21Mpa and the thermal conductivity is about0.032w(m·k).The flexibilizer glycol lower viscosity and improve the foam's tensile strength, but will affect to the structure of the foam.4-8%is relatively appropriate.