Method for producing a hollow molded part and hollow molded part obtained therefrom

A method for producing a hollow molded part, comprising producing the hollow molded part by fluid assistance injection molding, the method comprising the steps:

• Step (1):
• molten resin composition is injected into a mold having a mold cavity (1) and at least one overflow cavity (4), wherein the mold cavity (1) includes a mold main conduit (2) and a plurality of mold branches (6) which are connected with the mold main conduit (2), the resin composition is a semi-aromatic polyamide resin composition, the mold main conduit (2) has an inflection point (i) at which variation trend of the major axes changes, the major axis is the longer axis of each cross section of the mold main conduit (2) along its length direction or (ii) the joint point of the mold main conduit (2) and the closest mold branch (6) if the major axes have the same length,
• Step (2):
• fluid is injected into the molten resin composition via a fluid inlet (5) to obtain the molded part, the fluid inlet (5) is located inside the mold main conduit (2), and the distance LF, which is from the fluid inlet (5) to a plane D0, is not less than ½ of the distance L2, which is from the plane D0 to the end of the longest mold branch (6), the plane D0 is the one which the inflection joint is located in and is perpendicular to the length direction of the mold main conduit (2), and
• Step (3):
• demold the molded part,
• wherein the molded part is one-piece and has a main conduit at one end and a plurality of branches at the other end, the branches are connected with the main conduit, wherein the molded part is made from a semi-aromatic polyamide resin composition.