A reciprocating blow molding unit includes an extruder screw foundation and an extrusion unit coupled to the extruder screw foundation. The extruder screw foundation includes a screw housing formed to include an interior cavity configured to receive polymeric material. The extrusion unit includes an extruder screw arranged to lie at least partially within the interior cavity and is configured to rotate about a longitudinal rotation axis to advance the polymeric material through the interior cavity.

A worm shaft for a mixing and kneading machine particularly for continual processing having a shaft bar, on the circumferential surface of which blade elements are arranged to be spaced apart from one another extending outwards from the circumferential surface of the shaft bar, wherein the blade elements are arranged on the circumferential surface of the shaft bar, at least in one section extending in the axial direction of the worm shaft, in two rows extending in the axial direction of the worm shaft, and wherein each of the blade elements of the at least one section extending in the axial direction of the worm shaft has an elliptic, oval, or biconvex outer peripheral surface in the top view.

A worm shaft for a mixing and kneading machine particularly for continual processing having a shaft bar, on the circumferential surface of which blade elements are arranged to be spaced apart from one another extending outwards from the circumferential surface of the shaft bar, wherein the blade elements are arranged on the circumferential surface of the shaft bar, at least in one section extending in the axial direction of the worm shaft, in two rows extending in the axial direction of the worm shaft, and wherein each of the blade elements of the at least one section extending in the axial direction of the worm shaft has an elliptic, oval, or biconvex outer peripheral surface in the top view.

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 worm shaft for a mixing and kneading machine particularly for continual processing having a shaft bar, on the circumferential surface of which blade elements are arranged to be spaced apart from one another extending outwards from the circumferential surface of the shaft bar, wherein the blade elements are arranged on the circumferential surface of the shaft bar, at least in one section extending in the axial direction of the worm shaft, in two rows extending in the axial direction of the worm shaft, and wherein each of the blade elements of the at least one section extending in the axial direction of the worm shaft has an elliptic, oval, or biconvex outer peripheral surface in the top view.

A worm shaft for a mixing and kneading machine particularly for continual processing having a shaft bar, on the circumferential surface of which blade elements are arranged to be spaced apart from one another extending outwards from the circumferential surface of the shaft bar, wherein the blade elements are arranged on the circumferential surface of the shaft bar, at least in one section extending in the axial direction of the worm shaft, in two rows extending in the axial direction of the worm shaft, and wherein each of the blade elements of the at least one section extending in the axial direction of the worm shaft has an elliptic, oval, or biconvex outer peripheral surface in the top view.

Molded polymer foam articles are described as having a novel 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. The surface region is further characterized as having compressed pneumatoceles. The novel foam structure is achieved even when molding polymer foam articles comprising a shape and volume wherein a sphere having a diameter between 2 cm and 1000 cm would fit within the article in at least one location without protruding from a surface of the article, and the article further has a total volume of more than 1000 cm.sup.3. Methods of making a stabilized molten polymer foam, and of making a molded polymer foam article using the stabilized molten polymer foam are also described.

Molded polymer foam articles are described as having a novel 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. The surface region is further characterized as having compressed pneumatoceles. The novel foam structure is achieved even when molding polymer foam articles comprising a shape and volume wherein a sphere having a diameter between 2 cm and 1000 cm would fit within the article in at least one location without protruding from a surface of the article, and the article further has a total volume of more than 1000 cm.sup.3. Methods of making a stabilized molten polymer foam, and of making a molded polymer foam article using the stabilized molten polymer foam are also described.

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).

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).