Optimizing Formula of Special Halogen-Free Flame Retardant EVA Cable Compound

The properties of halogen-free flame retarding ethylene-vinyl acetate(EVA)/magnesium hydroxide(MH)/microencapsule red phosphorus(RP) cable compound(EMP) were optimized through mixing of matrix resins,self made compatibilizer(E-g-M) and cooperating E-g-M with ethylene propylene diene monomer(EPDM).The result showed that mixing EVA with high density polyethylene(HDPE) could improve the tensile strength of EMP.When the mass ratio of EVA and HDPE was 3∶1,the tentile strength of EMP/HDPE cable compound could increase from 7.2 MPa to 9.7 MPa.Adding 12 phr E-g-M to EMP/HDPE cable compound,the tensile strength of EMP/HDPE cable increased from 9.7 MPa to 12.8 MPa,the impact strength increased from 26.5 kJ/m2 to 29.4 kJ/m2,the elongation at break raised from 63.7% to 97.8%,which demonstrated E-g-M had a role of enhancing the strength and toughness of cable at the same time.When adding 5 phr EPDM to EMP/HDPE/E-g-M,the toughness of the cable compound had further improvment,its impact strength and the enlongation at break increased to 35.8 kJ/m2 and 162.2%,respectively.Cooperating E-g-M with EPDM had slightly influence on the tensile strength,flame retardant performance and processability of EPM cable compound.Compared with the standard of low smoke halogen-free flame retardant cable compound,the mechanical properties and flame retardant performance of EMP/HDPE/E-g-M /EPDM cable compound were all higher than those of the standard of YD/T 1113—2001.