High-temperature flame-retardant filter material and preparation method thereof

The invention provides a preparation method of a high-temperature flame-retardant filter material. The preparation method comprises the following steps: S1, singeing and calendaring: carrying out singeing process treatment on the upper surface of a needled felt; the singed needled felt is put into a pressing roller to be subjected to press polish; s2, preparing a composite flame-retardant finishing agent: uniformly mixing and stirring 20-30% of ammonium polyphosphate, 1-2% of a silane coupling agent, 0.5-1% of alumina sol, 3-5% of a penetrant, 1-2% of a cross-linking agent, 5-20% of silicone oil, 3-6% of a radiation sensitive agent and 2-5% of graphene to prepare the composite flame-retardant finishing agent; s3, preparing a high-temperature flame-retardant filter material: putting the needled felt subjected to singeing and calendering in the step S1 into the composite flame-retardant finishing agent prepared in the step S2, and carrying out dipping treatment; the impregnated needled felt is placed in a low-e