A method for reducing fluctuations over time in discharge of a plastics composition when extruding plastics products, including melting plastics material in an extruder and supplying the plastics material to an extrusion die by way of one or more extruder screws arranged in the extruder, and conveying a plastics composition along an extrusion axis by rotating the one or more extruder screws as pressure builds up, wherein discharge of the plastics material at a transition region from the extruder to the extrusion die or in the extrusion die is kept constant by changing a rotational speed of the one or more extruder screws, and wherein changing the rotational speed is carried out within one revolution of the one or more extruder screws.

Improvements in the extrusion of thermohardenable materials are achieved by cooling the material in the initial zone of the extruder and reducing residence time by use of a prescribed length to diameter ratio and screw speed, particularly useful for intermittent application during robotically controlled mass production.

A method of extruding a material including a binder and one or more energetic fillers and using an installation including an extruder including a sheath having at least one extrusion screw present therein, the extruder having at least one acoustic sensor fastened on the sheath, and a monitor system suitable for detecting an anomaly as a function of the acoustic signal picked up by the acoustic sensor, the monitor system being configured to measure variations in the amplitude of the acoustic signal picked up by the acoustic sensor, the method including an extrusion step for extruding the material through the extruder during which the acoustic signal picked up by the sensor is analyzed by the monitor system, and a detection step for detecting variation in the composition of the extruded material from variation in the amplitude of the acoustic signal.

The present invention relates to a processing technology for manufacturing seepage irrigation pipe with alternating effluent sections and non-effluent sections, and in particular, to the field of underground seepage irrigation in agriculture and forestry. The processing technology combines the production unit for water-effluent pipes with the production unit for non-effluent pipes, and produces the seepage irrigation pipeline by adjusting the raw material ratios, controlling the spindle speed, spindle acceleration time, and spindle deceleration time of the two pipeline production units, to generate a seepage irrigation pipe with alternating effluent sections and non-effluent sections. The lengths of the effluent sections and non-effluent sections can be adjusted, the pipe wall thickness can also be adjusted by adjusting the inner and outer diameter of the internal mold of the pipe forming unit, a seepage irrigation pipe with alternating effluent sections and non-effluent sections is environment-friendly, efficient, water-saving, and useful for underground irrigation.

Disclosed is a flame-retardant HIPS material and a preparation method thereof, comprising the following components: 90 parts to 67 parts of a HIPS resin; 8 parts to 15 parts of a brominated flame retardant; and 3 parts to 7 parts of an auxiliary flame retardant; wherein the auxiliary flame retardant is a 1,3,5-triazine compound. In the present invention, a synergistic compounding of the brominated flame retardant and the auxiliary flame retardant effectively reduces an amount of the brominated flame retardant, and a stable UL 94 (1.5 mm) V-0 flame-retardant class can be achieved. Compared with the existing brominated flame-retardant HIPS, the present invention has a low halogen content, low gas, and high cost performance ratio, which avoids excessive acid gas from forming air lines on the surface of parts, has a good appearance.

Disclosed is a process for preparation of a propylene-based polymer composition involving the steps of: (a) mixing a propylene-based polymer and a peroxydicarbonate in a mixing device, wherein the mixing takes place at a temperature of ≤30° C., wherein the peroxydicarbonate is introduced into the mixing process in a dry form; (b) keeping the mixed composition at a temperature of ≤30° C.; (c) feeding the mixed composition into a melt extruder; (d) homogenizing the mixed composition at a temperature where the propylene-based polymer is in solid state during an average residence time of ≥6.0 and ≤30.0 seconds; (e) further homogenizing the mixed composition at a temperature at which the propylene-based polymer is in the molten state; and (f) extruding the homogenized material from a die outlet of the melt extruder followed by cooling and solidification; wherein the steps (a) through (f) are conducted in that order.

A cooling apparatus for an extruder includes a supply line configured to receive bulk coolant from a supply circuit via an inlet. The supply line delivers supply coolant to the extruder along a flow path. A return line communicates expelled coolant from the extruder, and a circulation line connects the supply line to the return line. The circulation line supplies a recirculated portion of the expelled coolant to the supply line and mixes the bulk coolant with the recirculated portion of the expelled coolant forming the supply coolant. A bypass line connects the supply line to the return line, and a flow control valve connects one of the supply line and the return line to the bypass line. A proportion of the expelled coolant to the bulk coolant forming the supply coolant is adjusted by the flow control valve to control the temperature of the supply coolant.

A method of recycling a mixed plastic waste comprising plastics having different melting temperatures includes conveying the mixed plastic waste through an extruder such that at least some of the higher melting point plastic is passes through the extruder without melting and is present in the extrudate as solid material.

The invention relates an extrusion device (100) for extruding a semi¬finished product made of elastomeric material, comprising an extrusion body (10) extending along a feeding direction (A) and a pump (20) arranged downstream of the extrusion body (10) along said feeding direction (A). The extrusion body (10) comprises a hopper (30) for loading an elastomeric material and an extrusion screw (50) extending along said feeding direction (A) and having an inlet portion (50a) arranged close to the hopper (30) and an exit portion (50b) arranged close to the pump (20). The extrusion body (10) also comprises a motorised roller (40) arranged at the inlet portion (50a) of the extrusion screw (50) and configured to receive the elastomeric material from the hopper (30) and feed it to the extrusion screw (30). The extrusion screw (50) has a length and a diameter such that the ratio between length and diameter is comprised between 4 mm and 8 mm. The invention also relates to an extrusion process carried out through the aforementioned extrusion device (100).

Improvements in the extrusion of thermohardenable materials are achieved by cooling the material in the initial zone of the extruder and reducing residence time by use of a prescribed length to diameter ratio and screw speed, particularly useful for intermittent application during robotically controlled mass production.