In recent years, the use of residue for the production of new composite materials has gained prominence as it enables reuse of materials and contributes to the value of residue which, in individual form, usually has no significance. In the present work, composite formulations were developed using residues from the laminated polymer packaging by addition of different amounts of discarded foundry sand (30, 50, and 70% by mass) as filler. The composites were evaluated for their physical, thermal, mechanical, and toxicological properties, as well as their behavior against exposure to weathering by ultraviolet radiation. The primary results indicate that the adopted process enables the incorporation of high contents (mass fraction) of sand in the polymer. However, with increase in the sand content, the mechanical properties of the composites gradually degrade, leading to increase in the stiffness and density. By ecotoxicity tests, it was observed that, the presence of discarded foundry sand also increases the toxicity of the samples.