Casting polyurethane elastomer as well as preparation method and application thereof

The invention discloses a casting polyurethane elastomer as well as a preparation method and an application thereof. The casting material is composed of a component A and a component B with a mass ratio of 100/(8-12), wherein the component A is composed of TODI, macromolecule polyalcohol and a catalyst and the component B is composed of a diamine chain extender and a three-functionality micromolecule alcohol chain extender. The TODI and the macromolecule polyalcohol are added to a reactor to be stirred and mixed; then, a reaction is carried out on the mixture for 1.5-2.5 hours at a temperature of 75-95 DEG C to obtain a prepolymer; the prepolymer is heated to 70-90 DEG C, the chain extender component is heated to 110-130 DEG C, the prepolymer and the chain extender component are mixed, stirred, degassed and cast into a mould with a temperature of 90-120 DEG C; the mould is demoulded after 20-40 minutes of curing at a temperature of 90-120 DEG C; and the demoulded product is cured for 16-24 hours at a temperature of 90-110 DEG C. The elastomer is suitable to serve as a sealing element for a medium high-pressure hydraulic system, a sealing element for a pneumatic system and high-performance roller wheels and rubber covered rollers.