Blowing agent introduction polymeric foam processing methods and systems are described herein.

Aspects hereof provide methods for molding a single-phase solution comprised of a polymer composition and a gas. The polymer composition and the gas are maintained under pressure during the molding operation to prevent a cellular structure from being formed by the dissolved gas in the polymer composition coming out of solution. The mold cavity in which the single-phase solution is introduced for molding purposes is pressurized to a mold pressure that is sufficient to maintain the single-phase solution as a single-phase solution as the mold cavity is filled. Subsequent to filling the mold cavity with the single-phase solution under pressure, the resulting article may solidify entrapping the compressed gas, or the article may be exposed to a reduction in pressure causing the entrapped gas to form a cellular structure.

A foamed article is made by infusing the article of thermoplastic elastomer with a supercritical fluid, then removing the article from the supercritical fluid and either (i) immersing the article in a heated fluid or (ii) irradiating the article with infrared or microwave radiation.

A method for impregnating a polymeric granulate with a physical blowing agent is disclosed. The polymeric granulate can be a typical material such as a polycarbonate that is used in foam injection moulding processes. The physical blowing agent can be carbon dioxide which impregnates that polymeric granulate at a temperature range of 40 to 120 C. and a pressure range of 15 to 55 bar. Preferably, the polymeric granulate is heated in a range of 50 to 90 with a range of 60 to 80 preferred. A pressure range of 0 25 to 45 bar is preferred with a range of 30 to 40 bar more preferred.

An intra-mode moulding foam molding device of thermoplastic polymer particles and a molding method thereof. The device includes a supercritical fluid delivery system, a mould pressing foaming system, a preheating quantitative feeding system and a moving rail; the supercritical fluid delivery system communicates with the mould pressing foaming system. Through a one-step foam molding method of polymer particles, polymer particles can be directly added into a molding cavity without pre-foaming, water and anti-sticking separating agent are not needed; the molding process does not need high-pressure water vapor for warming and molding, and has great adhesion force and is also clean, therefore polymer materials are easy to hydrolyze. The processing needs few heat, the heating efficiency of the polymer particles is high, the temperature of the polymer particle is uniform, and a polymer particle microcellular foamed mould pressing molded product having fine pores, precise size and light weight is obtained.

The instant application discloses, among other things, ways to manufacture reduced density thermoplastics. A rapid foaming process which may create a polymer product by saturating thermoplastic sheet or preforms, heating, and then forming into final shape, is described. The polymer product may include an integral solid skin. This method may be utilized with any thermoplastic. The material handling, saturation methods, and end products are also described.

A method of making a foamed article, for example a foamed component for an article or footwear, comprises depositing an unfoamed, thermoplastic polymer onto a support surface in a three-dimensional printing process to form an unfoamed article; heating the article to soften the article and infusing the softened article with at least one inert gas at a first pressure greater than atmospheric pressure that is sufficient to cause the at least one inert gas to permeate into the softened article; and reducing the pressure to second pressure below the first pressure while the article is softened to at least partially foam the article, wherein a surface of a partial mold limits foam expansion in at least one direction but less than all directions. The article or a part of the article may be made by printing a thermoplastic polymeric material with a three-dimensional printer in a structure of interconnected, unfoamed, thermoplastic polymeric members spaced to define openings between the thermoplastic polymeric members.

Disclosed, among other things, are ways to manufacture layered structures. In one embodiment, a foaming process may produce layered structures in reduced density plastics with or without integral skins. In another embodiment, a foaming process may produce deep draw structures in reduced density plastics with or without integral skins. In yet another embodiment, a foaming process may utilize additives, blends, or fillers, for example. In yet another embodiment, a foaming process may involve saturating a semi-crystalline polymer such as Polylactic Acid (PLA) with high levels of gas, and then heating, which may produce a reduced density plastic having high levels of crystallinity. These processes may be used to generate products with layered structures.

A method of making a foamed article, for example a foamed component for an article or footwear, comprises forming a structure of interconnected, unfoamed, thermoplastic polymeric members spaced to define openings between the thermoplastic polymeric members. The structure may be made by printing a thermoplastic polymeric material with a three-dimensional printer. The thermoplastic polymeric members are heated to a first temperature to soften the thermoplastic polymeric members and the softened thermoplastic polymeric members are infused with at least one inert gas at a first pressure greater than atmospheric pressure. The first pressure is sufficient to cause the at least one inert gas to permeate into the softened thermoplastic polymeric members. After being infused with the inert gas, the pressure is reduced to at least partially foam the thermoplastic polymeric members.

Materials that exhibit stress-induced porosity, and methods of making and using the same, are described.