The present invention discloses a hybrid (mixed) formulation composition for 3D additive manufacturing and a manufacturing process. The hybrid formulation composition possesses capability of UV radiation curing and thermal curing. The hybrid formulation composition is designed to be cured by UV radiation in the 3D printing/additive manufacturing process and then post cure by heat to get its final properties. The hybrid formulation composition consists of acrylates (oligomer, monomer, and diluent), photoinitiators, and isocyanate-containing prepolymers which comprises poly-ols (di-ol, tri-ol), urea, urethane, and isocyanates. The hybrid formulation composition may also include reaction accelerator, dye, pigment, and fillers. The finished products of the hybrid formulation composition possess rubber-like properties and can be used in the applications such as shoe sole, toys, medical, and wearables goods . . . etc.