A method for producing a foamed extrudate comprises a device containing a main melting device and an auxiliary melting device. A first melt is generated in the main melting device, a second melt is generated in the auxiliary melting device from a meltable starting material. At least one reactive additive is added to the meltable starting material, wherein the at least one reactive additive being selected from the group consisting of a chemical blowing agent and an active nucleating agent is mixed in the auxiliary melting device with the second melt, so that an additive-containing second melt is obtained in the auxiliary melting device which is added to the first melt.

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.

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.

A polymeric sheet, at least partially cross-linked and/or foamed, having a substantially open cell foam structure is described. A continuous method of manufacturing of an at least partially cross-linked, open cell foamed polymeric sheet is also described.

The invention relates to an extrusion process for the production of expandable vinyl aromatic polymer granulate comprising mixing first and second additives with first and second polymer components, respectively, in dedicated mixers.

The invention relates to an extrusion process for the production of expandable vinyl aromatic polymer granulate comprising mixing first and second additives with first and second polymer components, respectively, in dedicated mixers.

A seal for a vacuum lifter and method of manufacture wherein the seal has a continuous unbroken outer fluid resistant skin of elastomer which forms a boundary around a homogeneous cellular structure with no interior seams or joints.

A three-dimensional printing system for preparing a three-dimensional object made at least partially of an expanded polymer includes a printing device configured to prepare an expandable polymer melt and deposit a strand of expandable, expanding or expanded polymer onto a surface and a three-dimensional movement device for to enable depositing of the strand of expandable, expanding or expanded polymer at a predetermined time at a precise position within the three-dimensional matrix. The printing device includes a feed section at an upstream end of the printing device, a heating section, a pressurizing section, a blowing agent supply line, a mixing section, a cooling section and a terminal printing head section at a downstream end of the printing device including a die configured to deposit the strand of the expandable, expanding or expanded polymer onto the surface.

A three-dimensional printing system for preparing a three-dimensional object made at least partially of an expanded polymer includes an autoclave, a printing device and a three-dimensional movement device. The printing device prepares an expandable polymer melt and deposits a strand of the expandable, expanding or expanded polymer onto a surface. The three-dimensional movement device adjusts the position of the printing device in a predefined three-dimensional matrix so as to enable depositing of the strand of expandable, expanding or expanded polymer at a predetermined time at a precise position within the three-dimensional matrix. The printing device includes a feed section, a cooling section, a backflow prevention section, a heating section and a terminal printing head section including a die for depositing the expandable, expanding or expanded polymer strand onto the surface.