A system for continuously treating recycled polymeric material includes a hopper configured to feed the recycled polymeric material into the system. An extruder can turn the recycled polymeric material in a molten material. In some embodiments, the extruder uses thermal fluids, electric heaters, and/or a separate heater. The molten material is depolymerized in a reactor. In some embodiments, a catalyst is used to aid in depolymerizing the material. In certain embodiments, the catalyst is contained in a permeable container. The depolymerized molten material can then be cooled via a heat exchanger. In some embodiments, multiple reactors are used. In certain embodiments, these reactors are connected in series. In some embodiments, the reactor(s) contain removable static mixer(s) and/or removable annular inserts.

The invention relates to a screw (1) for an extruder or conveyor (20), in particular extruder screw, conveying screw or dosing screw for polymers, having a web (3) running helically around a core (2), wherein the web (3) is formed undercut on its active conveying flank (4) in a conveying direction (F) at least in a section of the screw (1).

A powder supply method for causing a powder supplied from a top end 70t of a tube 70 to flow down within the tube 70 and be discharged from a bottom end 70b of the tube, in which if M [kg/s] is a supply flow rate of the powder and A.sub.S [m.sup.2] is a cross-sectional area of the bottom end 70b of the tube 70, the following expression is satisfied.

1.5≤(M/A.sub.S)≤135

With a mixing and kneading machine (100), wherein a worm shaft (12) moves in a housing (10) in a rotating manner and moves back and forth in a translatory movement, receptacles for kneading elements (12) are distributed non-uniformly. It is thereby possible to equip the receptacles with varying numbers of kneading elements. Quick adaptation is also thereby possible. In one embodiment, the number of kneading elements even varies over the extension direction of the mixing and kneading machine (100).

A machine produces foam-in-bag from foam precursors mixed within the bag. The machine comprises a base and a shell. The base and shell are moveable relative each other between a base/shell disengaged position and a base/shell engaged position. In the base/shell engaged position, the base and shell divide the bag so that a mixing chamber is isolated from the remainder portion of the bag. First and second nozzles inject foam precursors into the mixing chamber. A mixer engages the mixing chamber to provide mixing energy to facilitate the foam reaction.

A worm shaft for a mixing and kneading machine in particular for continuous preparation processes, comprising a shaft rod, on the circumferential surface of which blade elements are arranged which are spaced apart from one another and which extend outward from the circumferential surface of the shaft rod, wherein the blade elements are arranged on the shaft rod, at least in one section extending in the axial direction of the worm shaft, in three rows extending in the axial direction of the worm shaft, wherein at least one of the blade elements of one of the rows is different from one of the blade elements of one of the other rows, and/or the rows of blade elements, viewed in cross-section of the shaft rod, are distributed irregularly over the circumference defined by the outer circumferential surface of the shaft rod, and wherein the angular distance between the midpoints M of the outer circumferential surfaces of the blade elements on the circumferential surface of the shaft rod of adjacent rows differs between at least two of the three rows of the at least other two rows, and including wherein, for example, each of the blade elements of the at least one section extending in the axial direction of the worm shaft has a longitudinal extension which extends in an angle of 45° to 135° to the axial direction of the worm shaft.

A process and associated system for creating color effects using extrudable material, such as plastic and metal for example, are presented. Flows of first and second viscous materials of respective colors are provided and then combined in a predetermined pattern to form a stream of combined viscous material. A dynamic mixer is the then used to apply a predetermined dividing, overturning and combining motion to the stream of combined viscous material to partially mix the first viscous material and the second viscous material, such that upon exiting the dynamic mixer, the first material of the first color and the second material of the second color form a color pattern in the stream of combined viscous material. The dynamic mixer has elements configured for acquiring a specific radial orientation in a range of radial orientations that may be varied during the application of the dividing, overturning and combining motion to the stream of combined viscous material to cause variations in the color pattern in the stream of combined viscous material. Sheets of extruded material may be created using such process and system and used in the manufacturing of many different products including, but not limited to, kayaks, stand-up paddle boards, garden furniture and many others. In some embodiments, the sheets may be characterized by color bands extending diagonally with reference to a longitudinal extent of the sheet.

A screw element which has an axially asymmetrical screw cross-sectional profile which has at least two construction points located within the screw cross-sectional profile is provided. The screw element is suitable for use in an extruder having two drive shafts which rotate in the same direction and at the same speed, in order to process or produce plastic masses as an extrudate. Also, an arrangement of two identical or different screw elements in an extruder having two drive shafts which rotate in the same direction and at the same speed is provided. An extruder which is equipped with two identical or different screw elements and has two drive shafts which rotate in the same direction and at the same speed is provided. Furthermore, the use of the screw element according to the invention for processing or producing plastic masses is provided.

Continuous compounding systems include a feeding section and a compounding section. Method for compounding or mixing solid matter and liquid matter include providing a continuous compounding system, adding matter to the continuous compounding system, and mixing or compounding the matter.

The present invention relates to a single-stage process for the production of starch blends in a twin-screw extruder or two twin-screw extruders arranged in series, where i) the starch, together with a plasticizer, passes through a wetting section of length 8D to 30D in an extruder or in a wetting section of length 8D to 80D if two extruders are used at temperatures below the gelatinization temperature of the starch, with mixing, where D is defined as the screw diameter of the screw cylinder and the wetting section is defined as starting at that point on the extruder screw at which the starch and the entire or partial quantity of plasticizer encounter one another and ending at that point in the extruder at which the starch is gelatinized and is digested to give thermoplastic starch; ii) in a plastifying section of length 10D to 50D the extruder temperature is adjusted stepwise to above 130° C., where the starch is digested, destructured and thermoplastified, and is dispersed in a starch-immiscible polymer, and a water content below 5%, based on the starch blend, is established before the material leaves the extruder; where the starch-immiscible polymer is added in molten or granular form at any desired point in the extruder, and a mixture of all of the components present is consequently produced.