Study of magnesium oxide flame retardant EPDM rubber

EPDM has excellent heat resistance, aging resistance, corrosion resistance and insulation performance, and is widely used in wire and cable, automobile, home appliances and other fields, but EPDM is extremely flammable, and is restricted in some applications. In this paper, the feasibility of the application of 9,10-dihydro-9-oxa-10-phospha-phenanthrene oxide (DOPO) in EPDM rubber is discussed.

DOPO is a new type of phosphonolactone flame retardant, which has good flame retardant effect in epoxy resin, but it is not suitable for rubber flame retardant because of the active hydrogen atoms in the molecular structure of DOPO, which has serious inhibitory effect on rubber vulcanization.

In this paper, DOPO was reacted with KH-560 by chemical reaction to change the active hydrogen in the molecular structure of DOPO into ester structure to obtain a new type of flame retardant DK, which was used for the flame retardant of EPDM, and it was found that the flame retardant EPDM could not be vulcanized by conventional vulcanization method.

To solve this problem, this paper adopts metal oxide as the activator of peroxide vulcanizing agent, and finds that magnesium oxide and calcium hydroxide have activating effect on peroxide crosslinking, and further study also finds that magnesium oxide has co-effect on flame retardant, through the enhancement of silica, the activation of magnesium oxide, and the in situ reaction of KH-560 with DOPO to reduce the inhibition of crosslinking effect of DOPO and further with When the amount of DOPO was 20phr, the ultimate oxygen index of flame retardant EPDM reached 23.9 and the vertical combustion reached V-1 grade, and the tensile strength, elongation at tear and tear strength of vulcanized rubber were 18MPa, 592% and 61.1 The tensile strength, elongation at tear and tear strength are 18MPa, 592% and 61.1 kN/m respectively, which can meet the use of wire and cable.