A foam molding apparatus and a foam molding method thereby are proposed. The foam molding apparatus includes a foaming agent supply unit configured to supply a foaming agent, a molten resin supply unit configured to supply molten resin, a fixed mixing unit configured to produce a foaming resin-critical solution by mixing a foaming agent supplied from the foaming agent supply unit and molten resin supplied from the molten resin supply unit through a rod-shaped body, and a molding unit configured to mold a foam molding product using the foaming resin-critical solution supplied from the fixed mixing unit. Accordingly, it is possible to produce a foaming resin-critical solution by uniformly mixing a large amount of high-viscosity gel-state molten resin and a high-pressure compressed and low-viscosity foaming agent, using high-strength multiple channels.

The interior of a heating cylinder (2) is divided into a first stage (5) and a second stage (7) due to the shape of a screw (3). A first compression zone in which a resin is compressed is formed in the first stage (5). A starvation zone (7a) in which an inert gas is injected and a second compression zone in which the resin is compressed are formed in the second stage (7). A barrier flight (13) that is obtained by combining a main flight (14) and a sub-flight (15) having a greater lead angle than the main flight is provided to a section of the screw (3), said section corresponding to the first compression zone. A multiple flight is provided to another section of the screw (3), said section corresponding to the second stage (7).

A method for producing molded foam articles that molds molded foam articles continuously, the method comprising continuously repeating the following step 1, step 2, step 3 and step 4 in this order; wherein step 1 comprises melting a resin composition that includes a liquid crystal polyester; step 2 comprises introducing, with an introduction device, a supercritical fluid that is unreactive, in a supercritical state, with the liquid crystal polyester, and is a gas at normal temperature and normal pressure, into the resin composition in an amount of at least 0.1 parts by mass but not more than 0.3 parts by mass per 100 parts by mass of the liquid crystal polyester, and then melt-kneading the resultant mixture; step 3 comprises injecting the melt-kneaded resin composition containing the supercritical fluid into a mold; and step 4 comprises conducting foaming by lowering at least one of the pressure and the temperature of the supercritical fluid contained in the resin composition to a value below the critical point of the supercritical fluid, thereby producing a molded foam article. This liquid crystal polyester has a melt tension at a temperature 20° C. higher than the flow start temperature of at least 5 mN but not more than 100 mN.

A mixing device for producing a plastic melt loaded with propellant, from which a foamed plastic part is producible in a molding machine, includes a mixing chamber, at least one propellant inlet device for feeding propellant into the mixing chamber, an inlet channel for plastic melt, and an output channel for dispensing plastic melt loaded with propellant. A first gas-tight shutoff device is provided for closing the inlet channel, and a second gas-tight shutoff device is provided for closing the output channel.

A master batch composition for a weight-reduced plastic product includes a carrier resin, a core-shell foaming agent, and at least one lubricant. The core-shell foaming agent includes at least one outer polymeric shell and at least one inner foaming agent core. The outer polymeric shell encapsulates the inner foaming agent core. The inner foaming agent core includes alkane. The master batch composition is configured to be integrated into the weight-reduced plastic product by extrusion blow molding with a base plastic resin to create a foamed plastic having a foaming pore size from 10 to 80 μm.

The invention provides a valve disposed in a fluid supply path to control opening or closing of the supply path, configured to comprise, as components of the supply path, an inflow channel, a second channel, a first channel, and an outflow channel that are in communication with each other in sequence, in such a manner that fluid from a supply source entering the inflow channel passes through the second channel and the first channel in sequence and then flows out through the outflow channel. The valve further comprises a first valve piece and a second valve piece disposed movably in the first channel and the second channel respectively. Blocking or unblocking of the communication between the first channel and the outflow channel is controlled by movement of the first valve piece in the first channel, while blocking or unblocking of the communication between the inflow channel and the first channel via the second channel is controlled by movement of the second valve in the second channel. In this way, the valve enables opening or closing of the supply path through dual control by the first valve piece and the second valve piece.

According to the present invention, devolatilization of a synthetic resin formed from a polymer or synthetic rubber can be improved and the synthetic resin can be foamed at a low temperature by injecting a devolatilization agent through a devolatilization agent injection nozzle provided in a downstream end segment cylinder of a cylinder assembly. In a vented twin-screw kneading extrusion apparatus and extrusion method according to the present invention, a devolatilization agent, which is injected through a downstream end devolatilization agent injection nozzle provided on a downstream end segment cylinder constituted by a segment cylinder positioned on a downstream end of a cylinder assembly, is dispersed in molten resin in the downstream end segment cylinder and kneaded by a downstream end kneading portion such that the molten resin is foamed by the devolatilization agent and then extruded.

A method for producing molded foam articles that molds molded foam articles continuously, the method comprising continuously repeating the following step 1, step 2, step 3 and step 4 in this order; wherein step 1 comprises melting a resin composition that includes a liquid crystal polyester; step 2 comprises introducing, with an introduction device, a supercritical fluid that is unreactive, in a supercritical state, with the liquid crystal polyester, and is a gas at normal temperature and normal pressure, into the resin composition in an amount of at least 0.1 parts by mass but not more than 0.3 parts by mass per 100 parts by mass of the liquid crystal polyester, and then melt-kneading the resultant mixture; step 3 comprises injecting the melt-kneaded resin composition containing the supercritical fluid into a mold; and step 4 comprises conducting foaming by lowering at least one of the pressure and the temperature of the supercritical fluid contained in the resin composition to a value below the critical point of the supercritical fluid, thereby producing a molded foam article. This liquid crystal polyester has a melt tension at a temperature 20 C. higher than the flow start temperature of at least 5 mN but not more than 100 mN.

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

Polymeric foam processing systems and methods.