The present disclosure provides a process. In an embodiment, the process includes (A) providing a fitment with a base having a wall thickness (Tw). The base comprises an ethylene/a olefin multi-block copolymer. The process includes (B) placing the base between two opposing multilayer films. Each multilayer film has a respective seal layer comprising an olefin-based polymer. The process includes (C) positioning the base and opposing multilayer films between opposing seal bars. Each seal bar comprises (i) a front surface, (ii) a recessed surface a distance (x) behind the front surface, the recessed surface having a first end and an opposing second end. Each seal bar comprises (iii) a curved surface at each opposing end. The curved surface extends between the front surface and the recessed surface. Each curved surface has a radius of curvature (Rc) greater than or equal to distance (x). The process includes (D) heat sealing the base to each multilayer film.