US Patent 7976928 Resin molded article and molding method thereof

An annular mount base 11 continuously protruded from one face of a panel main body 3 and surrounding a through hole 9 has a dual structure of an inner mount base portion 17 and an outer mount base portion 19 which are joined to each other by four parts of a joint mount base portion 21. A skin layer 23 is formed at the surface of a door inner panel 1. An expanded layer 25 with a large number of pores is formed inside the panel main body 3. The mount base 11 and a part of the panel main body 3 between the inner mount base portion 17 and the outer mount base portion 19 are formed of a solid layer 27 having no expanded layer 25. Whereby, a lightweight resin molded article including a high-rigidity mount base is provided.