Since waste resins may be used as recycled raw materials, they are provided for reuse after collected separately, crushed and molten. However, because such waste resins based on polymers have different physical properties depending on their types, it is required to separate various types of waste resins precisely depending on their types so that waste resins may be recycled.
In general, waste resins are separated by using a difference in specific gravity. However, in the case of polyethylene (PE)/polypropylene (PP) having a specific gravity lower than that of water, such a way of separation is not adequate. When using such non-precisely separated resins having different physical properties in combination, compatibility between the resins is degraded and affinity of the resins to each other becomes insufficient, resulting in degradation of physical properties, such as impact resistance.
For example, Korean Utility Model No. 20-2001-24176 discloses a cost-efficient method for preparing a pallet using recycled plastics. However, the pallet recycled according to the above-mentioned related art is obtained by crushing waste resin materials and molding the crushed materials into the form of a pallet. In this case, there is a problem of degradation of impact resistance due to the low compatibility and affinity between heterogeneous waste resin materials.
USPTO Backgrounds
USPTO Backgrounds