Abstract: Described is an injection molding apparatus including a mold body having an inner surface defining a main cavity to contain primary molten polymeric material, a tank in fluid communication with the main cavity which contains auxiliary molten polymeric material, a pressurized vas injector in communication with the tank to inject the pressurized gas into the tank to displace part of the auxiliary molten polymeric material from the tank into the main cavity to prevent entry of the pressurized gas into the main cavity. The invention also relates to an injection molding plant for making an article and to an injection molding method for making an article. The apparatus, the plant and method for the injection molding of polymeric material according to the invention improve the mechanical properties and the aesthetic characteristics of an article to be made at or near the melt lines of the article.

Abstract: A component of a mold for molding preforms made of thermoplastic material, comprising at least a first part (10) and at least a second part (20) adapted to mold part of the outer surface of a preform, wherein, when the first part (10) and the second part (20) are assembled to each other, at least a first surface (11) of the first part (10) and at least a second surface (21) of the second part (20) face each other and are spaced apart from each other, thus delimiting a passageway for gases or vapors to leave the mold; and wherein at least one of said first surface (11) and said second surface (21) comprises laser-induced periodic surface structures (LIPSSs).

Abstract: A mold for injection molding processes and a molding process that uses the mold. The mold has, at at least one part of the surface of its cavity raised portions which are longitudinally extended, are arranged side by side and are oriented substantially in the direction of the flow of the melted plastic material that is injected. During the process, the surface of the cavity of the mold is kept at a temperature that is lower than the glass transition temperature, in the case of molding of plastic material constituted by amorphous polymers, and lower than the crystallization temperature, in the case of molding of plastic material constituted by semicrystalline polymers.