Molded polymer foam articles are described as having a novel a foam structure. The polymer foam articles include a continuous polymer matrix defining a plurality of pneumatoceles therein which is present throughout the entirety of the article, including in the surface region extending 500 microns beneath the surface of the article. The surface region is further characterized as having compressed pneumatoceles. The novel foam structure is achieved even when molding polymer foam articles comprising a thickness of more than 2 cm, a volume of more than 1000 cm.sup.3; or both a volume of more than 1000 cm.sup.3 and a thickness of more than 2 cm. Methods of making the molded polymer foam articles are also described.

A microcellular shoe stiffener has at least one adhesive layer coextruded with and carried on a stiffener core. A liquid, such as liquid nitrogen, is introduced into the extruder for the stiffener core to produce a closed cell foam with a gaseous component. The gas reduces the weight and cost of the stiffener with out significantly reducing stiffness and resiliency.

A mechanism for mixing a supercritical fluid and a polymer raw material melt provided by the present invention includes a hot-melting unit, a mixing unit, and a supercritical fluid supplying unit. The mixing unit, independently of the hot-melting unit, receives a polymer melt from the hot-melting unit and a supercritical fluid from the supercritical fluid supplying unit, respectively, and mixes the polymer melt and the supercritical fluid into a homogenous single-phase solution. The hot-melting unit is provided with a pushing member for pushing a polymer raw material. The mixing unit is provided with a mixing rotor for mixing the polymer melt and the supercritical fluid.

Pre-expanded polypropylene-based resin particles include a polypropylene-based resin. The polypropylene-based resin satisfies tan 0.32V+0.1, where tan represents a loss tangent at an angular frequency of 0.1 rad/s in dynamic viscoelastic behavior measurement at 200 C. and V represents a melt fracture take-up speed (m/min) at 200 C.

In an injection foam molding method, a relationship between a flow front moving speed (cm/s) of a foamed resin material in an injection step of injecting the foamed resin material into a cavity and amount of gas generated per 1 g of a resin material (ml/g) is defined as follows: the amount of gas generated per 1 g of the resin material is 0.36 ml/g or more; and the flow front moving speed (cm/s) is 75the amount of gas generated per 1 g of the resin material (ml/g)35 or more and 12 cm/s or more.

Molded polymer foam articles are described as having a novel a foam structure. The polymer foam articles include a continuous polymer matrix defining a plurality of pneumatoceles therein which is present throughout the entirety of the article, including in the surface region extending 500 microns beneath the surface of the article. The surface region is further characterized as having compressed pneumatoceles. The novel foam structure is achieved even when molding polymer foam articles comprising a thickness of more than 2 cm, a volume of more than 1000 cm.sup.3; or both a volume of more than 1000 cm.sup.3 and a thickness of more than 2 cm. Methods of making the molded polymer foam articles are also described.

A foamed material for shoes includes a foamed body made by foaming a mixture of a molten thermoplastic elastomeric material and a supercritical fluid. The foamed body has a density lower than 0.35 g/cm.sup.3, and includes multiple foamed pores, each of which extends in a longitudinal direction to terminate at two opposite lengthwise ends and in a width direction perpendicular to the longitudinal direction to terminate at two opposite widthwise ends. Each foamed pore has a maximum length defined by a distance between the lengthwise ends and a maximum width defined by a distance between the widthwise ends, and a ratio between the maximum length and the maximum width is at least 2:1. A method for manufacturing the foamed material is also disclosed.

This document discloses a process for manufacturing recyclable injection molded microcellular foams for use in, footwear components, seating components, protective gear components, and watersport accessories. The process includes the steps of providing a thermoplastic polymer which comprises at least one monomer derived from depolymerized post-consumer plastic, inserting a fluid into a barrel of a molding apparatus. The fluid is introduced under temperature and pressure conditions to produce a super critical fluid. The process further includes mixing the thermoplastic polymer and super critical fluid so as to create a single phase solution, and injecting the single phase solution into a mold of an injection molding machine under gas counter pressure. The process further includes foaming the single phase solution by controlling the head and temperature conditions within the mold.

A molding device includes a mold and a pressure regulating system. The mold has a mold cavity and a feeding port in communication with the mold cavity. The pressure regulating system includes a first gas conduit coupled to the mold cavity, a first valve disposed at the first gas conduit, a pressure sensing unit configured to sense the pressure in the mold cavity, a second gas conduit coupled to the mold cavity, a second valve disposed at the second gas conduit. A molding method includes: providing a mold; sensing the pressure in the mold cavity, and injecting gas until it is sensed that the mold cavity has reached a first predetermined pressure; sensing the pressure in the mold cavity, and filling a material into the mold cavity having the first predetermined pressure; and discharging the gas in the mold cavity.

A process of microcellular foam molding an article includes using a modifier to modify properties of amorphous PLA, pouring the modified amorphous PLA into a high pressure vessel, dissolving an SCF in the high pressure vessel to impregnate the modified amorphous PLA in the high pressure vessel which is configured to allow the SCF to effuse through, forming foamed pellets, conveying the foamed pellets to a mold in a second vessel filled with water or oil, heating the second vessel, and cooling the second vessel until a foamed article is finished in the mold.