Abstract: An article formed in a co-extrusion process comprises a base layer and a first cap layer disposed on the base layer. The base layer is formed from a thermoplastic olefin comprising a thermoplastic polymer, an elastomer, and a base filler. The base layer comprises greater than 15% by weight of the base filler. The first cap layer comprises at least one polyolefin and between 0-15% by weight of a first cap filler. The first cap layer has a thickness less than a thickness of the base layer. The first cap layer is configured to provide an exterior surface of the article resistant to whitening or fading caused by exposure to the ambient environment in comparison to the underlying base layer.