The invention relates to the technical field of
polymer composite materials, and discloses a lightweight
polymer material for a high roof outside a vehicle, which is prepared from the following raw materials in percentage by
mass: 50% of hard modified PU (
Polyurethane), 48% of
isocyanate modifier and 2% of reinforcing material, the
isocyanate modifier is formed by compounding
toluene diisocynate and
hexamethylene diisocyanate according to the
mass ratio of 3: 1, and the purity of the
isocyanate modifier is greater than or equal to 99.5%; the reinforcing material is one of glass fibers or
basalt fibers, the glass fibers are alkali-free chopped fibers, the length of the glass fibers is 3-5mm, and the
diameter of the glass fibers is 10-15 microns; the
basalt fiber is a chopped
fiber, the length is 2-4 mm, and the
diameter is 8-12 [mu] m. A compact protective film formed by the
polyurea bottom layer can effectively block
erosion of rainwater,
ultraviolet rays and chemical media; after a long-time
xenon arc lamp aging test, the surface of the material is free of cracks and discoloration, the water
absorption rate is far lower than that of a
glass fiber reinforced plastic material, and internal structure aging caused by rainwater infiltration can be avoided.