A preparation method of a high-rate foamed polylactic acid (PLA) sheet includes first-stage extrusion, second-stage extrusion, and foamed sheet extrusion. The method requires the following raw materials in parts by mass: 88 to 94 parts of PLA, 1 to 2 parts of a nucleating agent, 2 to 5 parts of a foaming agent, and 2 to 5 parts of an additive. The new method effectively solves the problems of low foaming rate, low strength, and the like in the industrial production using carbon dioxide, and a prepared PLA sheet with high foaming rate and excellent surface performance can be used in the fields of food packaging, disposable fully-degradable lunch boxes, and the like.

The invention relates to a biaxially oriented single-layer or multilayer porous film which comprises at least one porous layer and said layer comprises at least one propylene polymer, at least one -nucleating agent and particles, said particles having a melting point of over 200 C. and at most an agglomerate or at most a particle having a particle size of >1 m being detectable on a REM recording of a film sample of 10mm2.

A method of fabricating a foamed, injection-molded component is provided. The method includes the step of plasticizing pellets including a first polymeric material and a second polymeric material within an injection barrel to form an injection material. The first polymeric material defines a first phase of the injection material and the second polymeric material defines a second phase of the injection material. The first and second phases of the injection material are immiscible. The injection material is injected into a mold to fabricate the foamed injection-molded component having microscale, microcellular voids. Upon tensile loading, submicron, secondary phase cavities are formed in the injection-molded component, resulting in improved ductility and toughness.

In order to provide a manufacturing method of an elongated foam sheet capable of manufacturing the elongated foam sheet with highly-precise thickness without being limited by the material and thickness of foam material, a method of manufacturing an elongated foam sheet includes performing a slice process in which a foam sheet is created by slicing a foam block and a sheet pasting process in which a large number of foam sheets are arranged and pasted onto one side of an elongated base material sheet to manufacture the elongated foam sheet where the large number of foam sheets are lined up in a longitudinal direction of the base material sheet.