JP2003128795A - Method for producing polybenzazole formed material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polybenzazole formed material having excellent forming processability by carrying out stable polymerization of a polybenzazole polymer. SOLUTION: In this method for polymerizing a polybenzazole polymer in the presence of a solvent in a single screw extruder or a multi-screw extruder, extruding the formed polymer dope and directly transporting the dope to a forming machine and forming the polymer, the polybenzazole formed material is produced by controlling the number of revolutions of the single screw extruder or the multi-screw extruder so as to retain the pressure of the polymer dope in a preset range.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a PBZ polymer which is a rigid polymer which can be formed into fibers and films having high strength and high heat resistance. . 2. Description of the Related Art Conventional spinning of chemical fibers varies depending on the type of polymer, but is generally performed as follows. The polymerized polymer is once taken out of the reaction system and formed into chips. Thereafter, the mixture is dissolved or heated in a suitable solvent in a tank to form a viscous liquid by melting, extruded from a nozzle, and formed into a yarn. For film, extrude from die. Also, in a continuous production process from polymer polymerization to spinning, film forming and other forming machines, the polymer is transferred directly to the forming machine in a dope or molten state after leaving the polymerization machine, and is spun or formed. . However, once the polybenzazoles are removed from the reaction system, it is very difficult to dissolve them again in the solvent. In addition, polybenzazole dope has a very high viscosity, and it is impossible to stably transfer this high-viscosity dope to a molding machine with a conventional apparatus, and it is necessary to perform spinning, film forming, and the like with a constant quality. Could not. SUMMARY OF THE INVENTION The present invention provides a molding and processing apparatus in which a polybenzazole (PBZ) polymer having a constant degree of polymerization is constantly supplied stably, and the doping pressure at each part exiting the polymerization apparatus is kept constant. It is an object of the present invention to secure the safety of the apparatus by maintaining the PBZ, and to supply a fixed amount of the PBZ polymer stably so as to perform stable polymerization and improve moldability. Means for Solving the Problems The inventors of the present invention have made intensive studies and studies to achieve the above object, and have finally completed the present invention. That is, the present invention provides a method for polymerizing a polybenzazole polymer in a single-screw or multi-screw extruder in the presence of a solvent, extruding a produced polymer dope, and directly transferring the polymer dope to a molding machine to mold the polymer. A method for producing a polybenzazole molded article, characterized in that a polymer dope pressure is maintained within a preset range by controlling the number of revolutions of a multi-screw extruder. Polymerization of PBZ polymer is disclosed in
It is produced by reacting a PBZ oligomer with an aromatic dicarboxylic acid in a polymerization machine to increase the degree of polymerization of the polymer, as described in Japanese Patent Application Laid-Open No. H11-163,086. [0005] However, Z is O, S atom or NH group, and R ₁ -R ₄ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a halogen atom or a hydroxyl group. The N atoms may be in cis or trans positions. n is an integer of 1 to 4. The phenylenediamine derivative in the present invention is, for example, 4,6-diaminoresorcinol dihydrochloride, 2,5-diaminobenzene-1,4-dithiol dihydrochloride, 1,4-dihydroxy-3,6 -Diaminobenzene dihydrochloride, 4,6-dimercaptoresorcinol dihydrochloride, 1,3,4,6-tetraaminobenzene tetrahydrochloride, but are not limited thereto, and may have a substituent. good. The aromatic dicarboxylic acid in the present invention is specifically terephthalic acid, isophthalic acid, phthalic acid,
Methyl terephthalic acid, 2-ethyl terephthalic acid, 2,3
-Dimethylterephthalic acid, 2,6-dimethylterephthalic acid, 2-hydroxyterephthalic acid, 2,5-dihydroxyterephthalic acid, 2,5-dimethylterephthalic acid, 2,
Examples include, but are not limited to, 5-diethylterephthalic acid, 2,6-diethylterephthalic acid, 2-chloroterephthalic acid, and the like. The PBZ polymer in the present invention may be any polymer obtained by reacting the above-mentioned phenylenediamine derivative with one or more aromatic dicarboxylic acids. Trans-paraphenylenebenzobisoxazole), poly (cis- or trans-paraphenylenebenzobisthiazole), poly (cis-para-2'-methylphenylenebenzobisoxazole), poly (cis-para-2 ')
-Ethylphenylenebenzobisoxazole), poly (paraphenylenebenzobisimidazole), and copolymers thereof. [0010] The dope in the present invention is a solution of a PBZ oligomer or polymer using a mineral acid as a solvent. These dopes can be easily prepared by polymerizing a polymer or oligomer in a mineral acid solvent. Examples of the solvent include sulfuric acid, methanesulfonic acid, or polyphosphoric acid, and a mixed solvent thereof. The polymer concentration in the dope is 0.1-30.
%, Preferably 10 to 20%. As the polymerization solvent for the PBZ polymer, polyphosphoric acid is preferably used. The concentration of the polyphosphoric acid can be arbitrarily selected in a concentration range of 105 to 130%. Further, in order to adjust the concentration of polyphosphoric acid and increase dehydration ability, diphosphorus pentoxide or methanesulfonic acid can be added. The PBZ polymer of the present invention is produced by the following steps. (1) A phenylenediamine derivative and an aromatic dicarboxylic acid are mixed with stirring in a dehydration-condensation solvent while stirring at a temperature of 35 ° C. or higher to generate HCl gas. At this time,
The charge of the phenylenediamine derivative and the aromatic dicarboxylic acid was shifted from the equimolar point, and the charge amount of either one was 1 to 1
It may be reduced by about 5 mol%. Usually, the amount of phenylenediamine charged is increased. After generation of HCl gas, the reaction mixture is reacted at a temperature of 170 ° C. or lower to obtain an oligomer dope having a number average degree of polymerization of 20 to 100. (2) The oligomer dope from step (1) is transferred into a polymerization machine. In the polymerization machine, a slurry in which the oligomer dope and the aromatic dicarboxylic acid are dispersed in the above-described mineral acid solvent is supplied at a temperature of 150 ° C. or higher so as to have a desired polymerization degree, and the mixture is stirred and mixed to obtain a polymer dope. The piping to the reaction vessel, the oligomer dope tank and the polymerization machine in the step (1) in the present invention is made of a material which is not affected by the solvent. For example, an acid-resistant alloy such as stainless steel SUS316, SUS316L, and Hastelloy is used. The temperature of the tank and the piping is maintained within a temperature range in which the oligomer dope has fluidity and does not corrode the material. Usually, it is maintained at 70 to 200 ° C, preferably 120 to 180 ° C. The aromatic dicarboxylic acid slurry tank is also made of an acid-resistant material. The polymerization machine may be any one capable of stirring and mixing the oligomer dope and the aromatic dicarboxylic acid slurry. For example, there are a single screw extruder and a twin screw extruder. The viscosity of the polymer dope or the degree of polymerization of the polymer is measured for the material exiting the polymerization machine. These physical properties are adjusted by the ratio of the amount of the oligomer dope supplied to the polymerization machine to the amount of the aromatic dicarboxylic acid slurry. [0015] The polymerization machine is used in a temperature range of 100-300 ° C. Even if the temperature inside the polymerization machine is kept constant throughout the section, the temperature of the polymerization machine is kept relatively low at the junction of the oligomer dope and the aromatic dicarboxylic acid slurry, and thereafter a temperature gradient is provided so as to be optimal for polymerization. May be higher.
For the polymerization machine, a material that is not attacked even when contacted with the above-mentioned strong acidic solvent at a high temperature, for example, an alloy such as Hastelloy is used. The piping after the polymerization machine is also, for example, Hastelloy, SUS316, S
An alloy such as US316L is used. The dope transfer pump is also made of a material which is in contact with strong acids at high temperatures and is not attacked by these materials, for example, alloys such as Hastelloy, SUS316 and SUS316L. For example, a gear pump or the like is used for these pumps. Further, the transfer pump may be a combination of a booster pump and a metering pump in order to improve the quantitativeness of the supply of the oligomer dope or the aromatic dicarboxylic acid slurry. Examples of the processing machine include a spinning machine and a T-die extruder. Hereinafter, 4,6-diaminoresorcinol, terephthalic acid, and the production of poly (cis-paraphenylenebenzobisoxazole) (PBO) using these, which are one embodiment of the present invention, will be described with reference to the drawings. A method for specifically practicing the present invention will be described. FIG. 1 is a flowchart showing an embodiment of the present invention. The PBZ oligomer dope and the aromatic dicarboxylic acid slurry are fed into the polymerization machine by the transfer pumps 1 and 2, respectively, and after polymerization, transferred to the inlet of the processing apparatus by the polymer dope transfer pump and processed into various forms. The degree of polymerization of the oligomer increases in the polymerization machine and is prepared as a polymer dope having a desired degree of polymerization. The polymerization degree of the polymer is adjusted by the supply ratio of the PBZ oligomer dope and the aromatic dicarboxylic acid slurry. The inflow amounts of the oligomer dope and the aromatic dicarboxylic acid slurry into the polymerization machine are determined by the rotation speeds of the transfer pump 1 and the pump 2, respectively. Each transfer pump rotates at a constant speed set in advance. However, for system stability,
The rotation speed of the single-screw or multi-screw extruder in the polymerization apparatus is increased or decreased so that the dope pressure at the inlet of the pump 3 becomes constant. Next, a control method will be described with reference to FIG.
First, the processing apparatus inlet pressure is determined in a predetermined pressure range (P
_The pump 3 is rotated at a constant speed so that ₄ ± a) is obtained. However, if there is a slight difference between the amount of the dope discharged from the pump 3 and the amount of the dope used in the processing apparatus, the pressure at the processing apparatus inlet deviates from the set range for a long time. Therefore, PID control of the rotation speed of the pump 3 may be performed by a computer. The constants required for PID control are adjusted and determined according to the dynamic characteristics of the system. In order to keep the discharge efficiency of the pump 3 constant, the rotational speed r of the single-screw or multi-screw extruder in the polymerization apparatus is adjusted so that the inlet pressure of the pump 3 falls within a predetermined pressure range (P ₃ ± b). Is changed. Here, PID control is performed by a computer. The constants required for PID control are adjusted and determined according to the dynamic characteristics of the system. By changing the rotation speed of a single-screw or multi-screw extruder, the pump 3
Keeping the dope pressure at the inlet of a constant means to correspond to a temporary fluctuation of the dope flow rate for some reason. However, this control changes the distribution of the oligomer dope and the state of stirring in the polymerization machine, and is closely related to the properties of the polymer dope formed by polymerization and the polymer itself. It is preferable to keep the increase and decrease in the stirring rotation speed within 50%. More preferably, it is preferably within 30%. The operation amount of the single-screw or multi-screw extruder in the polymerization apparatus may be determined as follows. When the inlet pressure of the pump 3 becomes higher than (P ₃ + b), the rotation speed is reduced by R ₁ rpm. Or, if the inlet pressure of the pump 3 is (P ₃ −
When it becomes lower than b), the rotation speed is increased by R ₁ rpm. At this time, the deviation from the pressure reference value and the operation amount may be set in multiple stages. Further, the operation amount of the single-screw or multi-screw extruder in the polymerization apparatus may be determined as follows. When the inlet pressure of the pump 3 becomes higher than (P ₃ + b), the rotation speed is reduced by R ₁ rpm. After a certain period of time, the inlet pressure P _3t of the pump ₃ is measured, the gradient of the pressure change is obtained, and the operation of the next single-screw or multi-screw extruder is controlled so as to fall within the target pressure range (P ₃ ± b). The quantity is determined by proportional calculation. Further, after a lapse of a certain time, the next operation amount is repeatedly determined by proportional calculation from the difference between the current instruction pressure and the target pressure. The method of controlling the rotation speed of the single-screw or multi-screw polymerization machine to keep the inlet pressure of the polymer dope transfer pump constant is not limited to these. Next, examples to which the present invention is applied and comparative examples will be described, but the present invention is not limited to these examples. The measured values in the examples are measured by the following methods. Viscosity of PBZ polymer: Measured at 25 ° C. using methanesulfonic acid as a solvent. Spinning conditions: 334 holes, hole diameter 0.22 mm, die area 54.1c
The polymer dope was extruded under the conditions of m ² and a die temperature of 180 ° C., and spinning was performed. (Example 1) 43.7 k of 116% polyphosphoric acid
After adding 14.5 kg of diphosphorus pentoxide to the g under a nitrogen stream, 6.89 kg of terephthalic acid and 9.10 kg of 4,6-diaminoresorcinol dihydrochloride were added, followed by stirring and mixing at 70 ° C. for 30 minutes. 6 hours at 120 ° C, 1 more
The mixture was stirred at 35 ° C. for 16 hours to obtain an oligomer dope. The color of the oligomer dope is yellow, and its intrinsic viscosity is 6.
It was 3 dL / g. Further, 0.6 kg of terephthalic acid was dispersed in 8 kg of 116% polyphosphoric acid to obtain a terephthalic acid slurry. The transfer pump 1 (2 cc / r
The oligomer dope was supplied to the polymerization machine at a rotation speed of ev) of 20 rpm. At the same time, transfer pump 2 (0.5cc /
The terephthalic acid slurry was supplied into the polymerization machine at a rotation speed of rev) of 18 rpm. A single screw extruder was used as a polymerization machine. The oligomer and terephthalic acid were reacted at a temperature in the polymerization machine of 200 ° C. and a rotation speed of the single screw extruder at 150 rpm to obtain a polymer dope of poly (cis-paraphenylenebenzobisoxazole). The color of the polymer dope was yellow, and the intrinsic viscosity was 28.5 dL / g. A spinning machine was used as a molding device, and a polymer dope line was connected. The pressure at the spinning nozzle inlet is 175
The control according to the present invention was performed so as to maintain the pressure at the inlet of the transfer pump 3 at 15.5 MPa at 1 ° C. in the range of 1 ± 0.3 MPa. As shown in FIG. 3, when the pressure at the inlet of the pump 3 exceeded the range of 1 ± 0.3 MPa, the rotation speed of the single screw extruder was increased or decreased by 20 rpm. Pressure is 1 ±
When it entered the range of 0.3 MPa, the rotation speed of the single screw extruder was returned to 150 rpm. The operation was continued for 16 hours while monitoring the pressure every other minute and adjusting the rotation speed of the single screw extruder. At this time, the pressure fluctuation at the inlet of the spinning nozzle is extremely small and fluctuates within a range of 15.5 ± 0.5 MPa.
It was stable. FIG. 4 shows the pressure fluctuation at the inlet of the pump 3. It was extremely stable. Table 1 shows the operability and properties of the yarn obtained. Example 2 In the same manner as in Example 1, each raw material was charged, and an oligomer dope and a terephthalic acid slurry were prepared. Further, in the same manner as in Example 1, the terephthalic acid slurry was supplied into the polymerization machine. Set the temperature in the polymerization machine to 20
The oligomer was reacted with terephthalic acid at 0 ° C. to obtain a polymer dope of poly (cis-paraphenylenebenzobisoxazole). The intrinsic viscosity was 28.2 dL / g. The initial pressure at the inlet of the spinning nozzle is 1 at 175 ° C.
It was 4.8 MPa. As shown in FIG. 5, when the inlet pressure of the pump 3 exceeded the range of 1 ± 0.3 MPa, the rotation speed of the twin-screw extruder was increased or decreased by 20 rpm. Also,
When the inlet pressure of the pump 3 exceeded the range of 1 ± 0.3 MPa, the rotation speed of the twin-screw extruder was increased or decreased by 30 rpm. When the inlet pressure of the pump 3 entered the range of 1 ± 0.3 MPa, the rotation speed of the twin-screw extruder was returned to 150 rpm. First, the inlet pressure of the pump 3 was set to 1.6 MPa, and the rotation speed control of the twin-screw extruder was started. While monitoring the pressure every other minute and adjusting the rotation speed of the twin-screw extruder,
The operation was continued for 16 hours. At this time, the pressure fluctuation at the inlet of the spinning nozzle was extremely small, fluctuated within a range of 15.5 ± 0.5 MPa, and was stable. FIG. 6 shows the pressure fluctuation at the inlet of the pump 3. It was extremely stable. Table 1 shows the operability and properties of the yarn obtained. Example 3 In the same manner as in Example 1, each raw material was charged, and an oligomer dope and a terephthalic acid slurry were prepared. Further, in the same manner as in Example 1, the terephthalic acid slurry was supplied into the polymerization machine. A triaxial extruder was used as a polymerization machine. The oligomer and terephthalic acid were reacted at a temperature of 200 ° C. in the polymerization machine to obtain a polymer dope of poly (cis-paraphenylenebenzobisoxazole). The intrinsic viscosity was 28.8 dL / g. The initial pressure at the spinning nozzle inlet was 15.2 MPa at 175 ° C. As shown in Fig. 7, the inlet pressure of pump 3 is 1 ± 0.3M
When the pressure exceeds the range of Pa, the rotation speed of the triaxial extruder is set to 2
It was made to increase and decrease 0 rpm. Pump 3 inlet pressure is 1 ±
When it entered the range of 0.3 MPa, the rotation speed of the twin-screw extruder was returned to 150 rpm. The operation was continued for 16 hours while monitoring the pressure every other minute and adjusting the rotation speed of the twin-screw extruder. At this time, the pressure fluctuation at the inlet of the spinning nozzle was extremely small, fluctuated within a range of 15.5 ± 0.5 MPa, and was stable. FIG. 8 shows the pressure fluctuation at the inlet of the pump 3. It was extremely stable. Table 1 shows the operability and properties of the yarn obtained. Example 4 In the same manner as in Example 1, each raw material was charged, and an oligomer dope and a terephthalic acid slurry were prepared. Further, in the same manner as in Example 1, the terephthalic acid slurry was supplied into the polymerization machine. A twin screw extruder was used as a polymerization machine. The oligomer and terephthalic acid were reacted at a temperature of 200 ° C. in the polymerization machine to obtain a polymer dope of poly (cis-paraphenylenebenzobisoxazole). The intrinsic viscosity was 29.2 dL / g. The initial pressure at the inlet of the spinning nozzle was 15.9 MPa at 175 ° C. As shown in Fig. 9, the inlet pressure of pump 3 is 1 ± 0.5MP
a, the rotational speed of the twin-screw extruder is increased to 30 r.
pm. 0.5 minutes later, when the inlet pressure of the pump 3 was 1.3 to 1.5 MPa, the rotation speed of the twin-screw extruder was set to 130 rpm, and when it was 0.7 to 0.5 MPa, it was set to 170 rpm. Pump 3 inlet pressure is 1 ±
After entering the range of 0.3 MPa, pump 3
Was checked for inlet pressure. Thus, the operation was continuously performed for 16 hours. At this time, the pressure fluctuation at the inlet of the spinning nozzle was extremely small, fluctuated within a range of 15.5 ± 0.4 MPa, and was stable. Fig. 1 shows the inlet pressure fluctuation of the pump 3.
0 is shown. It was extremely stable. Table 1 shows the operability and properties of the yarn obtained. Example 5 In the same manner as in Example 1, each raw material was charged, and an oligomer dope and a terephthalic acid slurry were prepared. Further, in the same manner as in Example 1, the terephthalic acid slurry was supplied into the polymerization machine. Set the temperature in the polymerization machine to 20
The oligomer was reacted with terephthalic acid at 0 ° C. to obtain a polymer dope of poly (cis-paraphenylenebenzobisoxazole). The intrinsic viscosity was 28.2 dL / g. The initial pressure at the inlet of the spinning nozzle is 1 at 175 ° C.
It was 5.3 MPa. As shown in FIG. 11, when the inlet pressure of the pump 3 exceeded the range of 1 ± 0.5 MPa, the rotation speed of the twin-screw extruder was increased or decreased by 30 rpm. If 0.5 minute after the operation, the inlet pressure of the pump 3 becomes 1 ± 0.5MP
a, the difference between the current pressure value and the target value is determined, and the rotational speed of the pump 1 is adjusted to a pressure deviation of 0.1 MPa.
Per unit (30 x deviation from target value / 3) rpm. One minute after the operation, when the inlet pressure of the pump 3 was in the range of 1.3 to 1.5 or 0.5 to 0.7 MPa, the rotation speed of the twin-screw extruder was increased or decreased to 20 rpm. After that, the inlet pressure of the pump 3 becomes 1.3 to 0.7 MPa.
After entering the range, the pressure was checked every other minute. Thus, the operation was continuously performed for 16 hours. At this time, the pressure fluctuation at the inlet of the spinning nozzle was extremely small, and was 15.5.
It fluctuated within a range of ± 0.5 MPa and was stable. FIG. 12 shows the inlet pressure fluctuation of the pump 3. It was extremely stable. Table 1 shows the operability and properties of the yarn obtained. Comparative Example 1 In the same manner as in Example 1, each raw material was charged, and an oligomer dope and a terephthalic acid slurry were prepared. Further, in the same manner as in Example 1, the terephthalic acid slurry was supplied into the polymerization machine. Set the temperature in the polymerization machine to 20
The oligomer was reacted with terephthalic acid at 0 ° C. to obtain a polymer dope of poly (cis-paraphenylenebenzobisoxazole). The color of the polymer dope was yellow, and the intrinsic viscosity was 28.7 dL / g. The initial pressure at the inlet of the spinning nozzle was 15.6 MPa at 175 ° C. Without controlling according to the present invention, the rotation speed of each dope transfer pump was kept constant. As shown in FIG. 13, the inlet pressure of the pump 3 was very unstable, and finally the pressure became high, so that the supply of the dope had to be stopped. Table 1 shows the operability and properties of the yarn obtained. [Table 1] According to the present invention, polybenzazole (P
BZ) It has made it possible to provide a polybenzazole molded article having good moldability by performing stable polymerization of a polymer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a manufacturing method of the present invention. FIG. 2 is a block diagram of a control method in the manufacturing method of the present invention. FIG. 3 is a diagram illustrating pressure control of an inlet portion of a pump 3 according to the first embodiment. FIG. 4 is a diagram showing pressure fluctuations at an inlet portion of a pump 3 according to the first embodiment. FIG. 5 is a diagram illustrating pressure control of an inlet portion of a pump 3 according to the second embodiment. FIG. 6 is a diagram showing pressure fluctuations at an inlet of a pump 3 according to a second embodiment. FIG. 7 is a diagram showing pressure control of an inlet portion of a pump 3 according to a third embodiment. FIG. 8 is a diagram showing pressure fluctuations at an inlet of a pump 3 according to a third embodiment. FIG. 9 is a diagram illustrating pressure control of an inlet portion of a pump 3 according to a fourth embodiment. FIG. 10 is a diagram showing pressure fluctuations at an inlet of a pump 3 according to a fourth embodiment. FIG. 11 is a diagram showing pressure control of an inlet portion of a pump 3 according to a fifth embodiment. FIG. 12 is a diagram showing pressure fluctuations at an inlet of a pump 3 according to a fifth embodiment. FIG. 13 is a diagram showing pressure fluctuations at the inlet of the pump 3 in Comparative Example 1. [Description of Signs] 1: Oligomer tank, 2: Aromatic dicarboxylic acid slurry tank, 3: Transfer pump 1, 4: Transfer pump 2, 5:
Polymerizer, 6: pressure detector 1, 7: transfer pump 3, 8: pressure detector, 9: processing device.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B29K 81:00 B29K 81:00 C08L 79:04 C08L 79:04 (72) Inventor Go Matsuoka Otsu City, Shiga Prefecture 2-1-1 Katata Inside Toyobo Co., Ltd. Research Laboratory (72) Inventor Takahiro Nakagawa 10-24 Toyocho, Tsuruga-shi, Fukui Toyobo Co., Ltd. Tsuruga Plant F-term (reference) 4F071 AA58 AF14 AH19 BB06 BC01 4F207 AA34 AG01 AP02 AR02 AR09 KA01 KA17 KM05 KM15 4J043 PA19 PC015 PC065 PC135 QB33 RA03 RA42 RA52 RA57 SA06 SA08 SA71 SA83 TA02 TA03 TA12 TA42 UA121 UA122 XA11 YB05 YB13 ZA12 ZA31 ZB04 ZB01 4

Claims (1)

Claims: 1. A method for forming a polymer by polymerizing a polybenzazole polymer in a single-screw or multi-screw extruder in the presence of a solvent, extruding a produced polymer dope, and directly transferring the polymer dope to a molding machine. A method for producing a polybenzazole molded article, wherein the pressure of the polymer dope is maintained within a predetermined range by controlling the rotation speed of the single-screw or multi-screw extruder.