Abstract: A press-fitting connector for plastic composite pipes, comprised of an inner plastic layer, an outer plastic layer, and a middle metal layer, has a support member receiving the end of a plastic composite pipe. The support member has an outer collar having a first end face facing the plastic composite pipe and a second end face facing away from the plastic composite pipe. An insulating plastic ring is positioned at the first end face. A press-fit sleeve secures the pipe end on the support member. The outer collar has two diametrically opposed cutouts. The insulating plastic ring is a curved spring washer with two convexly curved and two concavely curved portions, wherein the convexly curved portions have monolithic, axis-parallel tongues engaging the cutouts of the circumferential rib. The axis-parallel tongues in the end position of the plastic composite pipe project partially from the cutouts past the second end face of the outer collar.