Modification Process Of Melamine Formaldehyde Resin

The technology of synthesis and modification of melamine formaldehyde resin,as well as the foaming process of the resin were studied.The optimized process conditions were obtained by testing the resin's solid content,viscosity,free formaldehyde content's and the foam's density,aperture structure,mechanical properties,thermal stability etc.The results were listed as follows:The resin was synthesized under the condition of n(M):n(F)=1:3;pH=9.0-10.0;reaction temperature and time were 90-95? and 75-100min.The resin's solid content was about 59%;the viscosity was 1000mPa·S;the free formaldehyde content was about 1%.The foam was prepared under the condition of the surfactant's dosage was 2%by using sodium dodecyl sulfate;the latent curing agent's dosage was 1%by using ammonium chloride;the foaming agent's dosage was 18%by using n-pentane;the curing agent's dosage was 2%by using oxalic acid;the foaming temperature and time were 80? and 100min.The foam's density was 32.47kg/m3;tensile stress was 21.38kPa.Used the PVA0588 as the modifier.The foam's density was 30.56 Kg/m3;tensile stress was 49.77kPa;limiting oxygen index was 34;thermal decomposition temperature was 270?.The data of CONE showed that the foam's pHRR was 94.10 kW·m-2;THR was 14.67 MJ-m-2;EHC was 2.72MJ·kg-1;SEA was 45.05 m2·kg-1;COY was 0.15 g-kg-1;TTI was 30s.The foam's compression strength and bending strength were 42.1 kPa and 39.8kPa.