The present invention relates to a method for producing a biodegradable resin expanded sheet, by which a biodegradable resin expanded sheet immediately after extrusion is brought into a predetermined cooled state in an extrusion expansion method, whereby good formability can be exerted.

The method for manufacturing a foamed product uses a manufacturing apparatus having a plasticizing cylinder in which an introduction port for introducing a physical blowing agent into a starvation zone is formed, and an introduction speed adjustment container connected to the introduction port, wherein the manufacturing method comprises: turning a thermoplastic resin into a molten resin; introducing the physical blowing agent at a predetermined pressure into the starvation zone through the introduction speed adjustment container and maintaining the starvation zone at a predetermined pressure; setting the molten resin to a starved state; bringing the molten resin in the starved state and the pressurized fluid into contact with each other; and molding the molten resin into a foamed product. The maximum value of the inner diameter of the introduction speed adjustment container is larger than the inner diameter of the introduction port.

An extruding system includes a melting unit configured to convey a polymeric material, a mixing unit configured to mix the polymeric material with a blowing agent to form a mixture, an injection unit configured to inject the mixture, a first flow control element disposed between the melting unit and the mixing unit, and a second flow control element disposed between the mixing unit and the injection unit. A method of extruding includes conveying a polymeric material from a melting unit to a mixing unit, conveying a blowing agent into the mixing unit, mixing the polymeric material with the blowing agent to form a mixture, conveying the mixture from the mixing unit to an injection unit, and discharging the mixture from the injection unit, wherein flow of the polymeric material is controlled by a first flow control element, and flow of the mixture is controlled by a second flow control element.

A method of making multilayer foam sheet from recycled polyester sources, which may be used for packaging applications. The method comprises a co-extrusion system comprising at least two single screw extruders. A low I.V. polyester feedstock comprising up to 100% of the polyester flakes from recycled sources with an intrinsic viscosity (I.V.) of lower than 0.8 dL/g as measured by ASTM D4603-18 is directly being fed into the extruders. Supercritical physical blowing agent is introduced into the melted polyester feedstock in at least one of the extruders wherein the processing temperature is in the range of 15% lower than the melting temperature and 15% higher than the melting temperature. Then, coextruding the feedstock from the extruders of the co-extrusion system through a flat sheet die to make a multilayer foam sheet, wherein at least one layer is a foam layer comprising low I.V. polyester.

A die for extrusion molding includes an extrusion port configured to extrude a plastic composition, and a plastic flow channel configured to cause the supplied plastic composition to flow to the extrusion port. The plastic flow channel includes a supply flow channel, and an extrusion flow channel. The supply flow channel is configured to be supplied with the plastic composition. The extrusion flow channel has an upstream end coupled to the supply flow channel, and downstream end having the extrusion port. In the extrusion flow channel, a flow channel cross-sectional area perpendicular to the flow direction of the plastic composition in the extrusion flow channel gradually changes to the extrusion port, and an inner wall surface of a flow channel has a protruding surface protruding toward an inside of the flow channel in a cross section including an extrusion central axis and parallel to the extrusion central axis.

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.

An extruding system includes a melting unit configured to convey a polymeric material, a mixing unit configured to mix the polymeric material with a blowing agent to form a mixture, an injection unit configured to inject the mixture, a first flow control element disposed between the melting unit and the mixing unit, and a second flow control element disposed between the mixing unit and the injection unit. A method of extruding includes conveying a polymeric material from a melting unit to a mixing unit, conveying a blowing agent into the mixing unit, mixing the polymeric material with the blowing agent to form a mixture, conveying the mixture from the mixing unit to an injection unit, and discharging the mixture from the injection unit, wherein flow of the polymeric material is controlled by a first flow control element, and flow of the mixture is controlled by a second flow control element.

Provided is a method for producing a shaping material that contains a cyclic olefin polymer and has a low content of a volatile impurity. This method for producing a shaping material is a method which includes passing a raw-material resin in a molten state through an extruder to produce a shaping material, and in which the extruder is equipped with a cylinder, a screw housed within the cylinder, a resin introduction port for introducing the raw-material resin into the cylinder, a resin discharge port for discharging the molten resin from the cylinder, a fluid injection port for injecting carbon dioxide or water into the cylinder between the resin introduction port and the resin discharge port, and a fluid discharge port for removing fluid in the cylinder by suction downstream of the fluid injection port and between the resin introduction port and the resin discharge port.

An apparatus having an extrusion machine and a feeding unit. for producing foamed polymeric material, in particular polyethylene and polypropylene, is disclosed. The extrusion machine includes a cylindrical barrel which is connected with a first end thereof to the feeding unit to receive a blend of plastic material to be extruded, a parallel pair of screws in the cylindrical barrel, a driving unit for driving the screws into rotation in opposite directions, a gas tank containing CO.sub.2 as a foaming gas, injection means for injecting the foaming gas into the cylindrical barrel; a head mounted at a second end of the cylindrical barrel opposite to the first end and heating means arranged around the cylindrical barrel for transferring heat thereto.

Provided is a method for producing a shaping material that contains a cyclic olefin polymer and has a low content of a volatile impurity. This method for producing a shaping material is a method which includes passing a raw-material resin in a molten state through an extruder to produce a shaping material, and in which the extruder is equipped with a cylinder, a screw housed within the cylinder, a resin introduction port for introducing the raw-material resin into the cylinder, a resin discharge port for discharging the molten resin from the cylinder, a fluid injection port for injecting carbon dioxide or water into the cylinder between the resin introduction port and the resin discharge port, and a fluid discharge port for removing fluid in the cylinder by suction downstream of the fluid injection port and between the resin introduction port and the resin discharge port.