The invention relates to a rigid
polyurethane casting material and a preparation method thereof. The rigid
polyurethane casting material is prepared from a component A and a component B, wherein the component A is polymethylene polyphenyl polyisocyanic acid ester of which NCO accounts for 30.5-32.5% in percentage by
mass, the functionality degree of the component A is within 2.5-3.0, and the use amount of the component A is 100 parts by weight; the component B comprises the following components: 30-80 parts of
polyester polyol, 10-30 parts of polyether
polyol, 20-50 parts of
flame-retardant polyhydric
alcohol, 4-5 parts of foam stabilizer, 0.5-2 parts of catalyst, 8-30 parts of
foaming agent, 2-8 parts of chain
extender, 1-4 parts of cross-linking agent and 10-30 parts of
flame retardant. The rigid
polyurethane casting material provided by the invention has the characteristics of light weight, high
specific strength, good sound insulation property, rich foam pore in a sealed manner, low heat conduction coefficient, good
corrosion resistance, good shake resistance, good size stability and the like, is applicable to various crack
filling materials, repairing materials, building wall body heat-preservation materials, sound insulation materials and the like, and is good in
flame retardance.