JP5799877B2 - Method for producing thermoplastic resin composition and extruder for powder raw material - Google Patents

Description

  The present invention relates to an extruder for powder raw materials. More specifically, while improving the biting performance of the powder raw material having a low apparent density, the trouble of blowing the unmelted raw material from the vent portion of the extruder is reduced, and a method for producing a thermoplastic resin composition with high production efficiency and The present invention relates to an extruder for achieving this.

  In general, a thermoplastic resin composition is made by adding a powdery reinforcing material such as a filler component to a thermoplastic resin and various function-imparting materials, granulated into pellets through an extruder, and then producing a product by a molding machine. Is done.

  However, when the thermoplastic resin is a powder or when extruding a powder raw material containing a large amount of powder reinforcing material, the apparent density is lower than that of the pellet-shaped raw material, so that the bite into the extruder is low. Has inferior issues. Also, when trying to increase the biting property, the melting becomes insufficient, and unmelted or poorly dispersed raw material is ejected from the vent port installed downstream, so in any case the extrusion amount is reduced and efficient production is achieved. Could not be done.

  Conventionally, the following techniques are known for extruding powder raw materials.

  For example, Patent Document 1 describes a method of using a screw configuration in which a single screw and a right twist kneading block having a specific twist angle are combined to improve the productivity of a resin composition containing a filler component at a high concentration. Has been.

  Patent Documents 2 and 3 describe a method using a screw configuration in which a single screw and a specific kneading block are arranged to improve the productivity of a resin composition using a powder raw material.

  Further, in Patent Document 4, the ratio D / d of the major axis D to the minor axis d of the screw flight part is defined for improving the productivity of the resin composition using the powder raw material, and a single groove screw is used while using a deep groove extruder. And a method using a screw configuration in which a specific kneading block is arranged is described as a method for improving the biting property of the powder raw material.

JP 9-29814 A JP-A-10-24483 Japanese Patent Laid-Open No. 10-180840 JP 2010-105285 A

  However, in the manufacturing method described in Patent Document 1, since only a right twist kneading block is used, compression is insufficient, kneading is insufficient, and powder raw materials and other raw materials are insufficiently melted. Or the raw material which could not be disperse | distributed up from the vent port installed downstream of the 1st fusion | melting part, and it might block | close.

  In the production methods described in Patent Documents 2 and 3, the kneading zone length may be 1.0 to 2 or more in L / D. However, in the L / D, the kneading zone is still too short. The raw materials and other raw materials were not sufficiently melted, and the raw materials that could not be melted or dispersed were blown up from the vent port disposed downstream of the first melting portion and sometimes blocked.

  Moreover, in order to suppress the blow-up at the vent port in the production methods described in Patent Documents 2 and 3, it is necessary to strengthen the kneading degree, but only by combining the elements described in the Patent Documents, kneading As a result, the degree of resin filling at the part increases, and the air that has entered the raw material flows back to the supply port side, resulting in poor biting of the raw material.

  In the manufacturing method described in Patent Document 4, the biting ability of the powder is improved. Regarding the composition of the first melting part, it is described that a combination of a specific kneading block with a right twist and a neutral kneading block can be suitably used. Occasionally, production was impossible.

  An object of the present invention is to further improve the extrusion efficiency by suppressing the blow-up at the vent port while ensuring the biting property of the powder raw material in order to solve the problems in the conventional technology as described above. It is in providing the manufacturing method of the thermoplastic resin composition which can be manufactured, and the extruder for powder raw materials.

The present inventors diligently studied to solve these problems, and reached the present invention. That is, the manufacturing method of the thermoplastic resin composition of the present invention and the powder raw material extruder used therefor are as follows.
1. A powder raw material extruder having two rotating shafts in the same direction, a first conveying unit to which the powder raw material is supplied, two or more kneading units and two or more conveying units downstream of the first conveying unit The ratio Lc1 / D between the overall length Lc1 of the first conveying unit and the screw major diameter D is 8 to 20, and at least one of the constituent screw elements has a lead length Ll. The ratio Ll / D to the screw major axis D is a single screw element of 0.7-2, and the first kneading part following the first conveying part is a ratio Lm1 / D between the overall length Lm1 and the screw major axis D. 5-12, and has at least one right twist kneading block and one left twist kneading block in its constituent elements, and the right twist kneading block has a disc width W1 and a screw length. The ratio W1 / D to D is 0.45 to 1, the twist angle is 10 to 30 °, and the left twist kneading block has a ratio W2 / D of the disk width W2 to the screw major axis D of 0.00. 1 to 0.3, a twist angle of 20 to 40 °, and a powder raw material extruder having a vent port in the second conveying section following the first kneading section, polyphenylene sulfide, polyamide resin and polyester A method for producing a thermoplastic resin composition, comprising supplying a powder raw material having an average particle diameter of 1 to 500 μm containing at least one thermoplastic resin selected from a resin and kneading and extruding.
2. 2. The method for producing a thermoplastic resin composition according to 1, wherein 0.1 to 50 parts by weight of an elastomer is blended and kneaded and extruded with respect to 100 parts by weight of the thermoplastic resin.
3. 3. The method for producing a thermoplastic resin composition according to 1 or 2, wherein a powder raw material having an apparent density of 0.1 to 0.7 g / ml is supplied and kneaded and extruded.
4). In the powder raw material extruder having a vacuum vent on the downstream side of the second kneading unit on the downstream side of the second transport unit, the degree of vacuum at at least one vacuum vent port is −60 kPa or less in terms of gauge pressure. The manufacturing method of the thermoplastic resin composition in any one of 1-3 .

  According to the method for producing a thermoplastic resin composition of the present invention and the powder raw material extruder, the vent port is provided while ensuring the biting property of the powder raw material, even though no significant improvement in production equipment is required. As a result, the production efficiency of the thermoplastic resin composition containing the powder raw material can be further improved, and the production of a highly cost-competitive thermoplastic resin composition becomes possible. .

It is a cross-sectional view which shows an example of the extruder used for this invention. It is a cross-sectional view which shows an example of the extruder to which the side feeder used for this invention is applied. It is the top view and side view which show an example of the single screw element used for the conveyance part of this invention. It is the top view and side view which show an example of the double screw element used for the conveyance part of this invention. It is the top view and side view which show an example of the kneading block of the right twist used for the kneading part of this invention. It is the top view and side view which show an example of the kneading block of the left twist used for the kneading part of this invention.

  The present invention relates to a method for producing a thermoplastic resin composition and an extruder for powder raw materials.

  Hereinafter, an embodiment of a powder raw material extruder of the present invention and a process of a method for producing a thermal composition resin will be described with reference to FIG.

  FIG. 1 is a cross-sectional view showing an example of an extruder according to the present invention. In FIG. 1, an extruder 1 is a co-rotating twin-screw extruder for powder raw materials.

  In the present invention, the screw configuration has a great feature, and as the screw of the conveying portion, a flight-like screw element that is usually used for the conveying portion, such as a single screw element, a double screw element, or a triple screw element, is used. However, it is important that the ratio Lc1 / D of the entire length Lc1 of the first conveying unit and the screw major axis D is 8 to 20. If Lc1 / D is less than 8, the carrying capacity is lowered, and even if Lc1 / D exceeds 20, no further improvement in carrying capacity can be expected. As a preferable value of Lc1 / D, Lc1 / D is 8.0 to 16.0. When Lc1 / D is in the above range, the total length L of the extruder can be shortened, which contributes to reduction in equipment costs.

  Further, it is important that at least one or more of the constituent screw elements of the first transport unit is a single screw having a ratio Ll / D between the lead length Ll and the screw major diameter D of 0.7 to 2. If the L / D of the lead length of the single screw is less than 0.7, the conveying capacity is lowered. If the lead length L / D exceeds 2, the conveying capacity is too large and the molten state in the first kneading part. Will become unstable and cause trouble. A preferred value of Ll / D is 1-2.

  Moreover, it is preferable that Lcs1 / D is 4-20 as for the whole length Lcs1 of a single screw. If Lcs1 is less than 4, the conveyance capacity is lowered. More preferably, it is 4-16.

  As a more preferable form, it is preferable to dispose a single screw element from the lower part of the supply port 2 which is the upstream side of the first transport unit 4. Moreover, although a double screw can also be used in the downstream of the 1st conveyance part 4, it can also be used for the connection part via a transition screw element.

  The first transport unit 4 calculates the length using the most upstream part of the barrel including the supply port 2 as a base point.

  The first kneading part 5 following the first transport part 4 is a part for applying a shearing force to the powder resin and kneading. It is important that the ratio Lm1 / D between the overall length Lm1 and the screw major axis D is 5-12. If Lm1 / D is less than 5, the molten state may be insufficient, which may cause troubles of unmelted raw material blowing up at the vent port. Or, since the powder raw material does not melt, the entrained air is not separated, the apparent filling rate of the kneading part is increased, and the entrained air is backflowed to the supply port 2 to inhibit the entrainment of the raw material containing the powder raw material. There are things to do. When Lm1 / D exceeds 12, the resin deteriorates, the resin is completely melted, the filling rate in the kneading section is increased, the entrained air is backflowed to the supply port 2, and the raw material including the powder raw material is caught. May be inhibited. The preferable value of Lm1 / D is 5.0 to 10.0. When Lm1 / D is in the above range, the total length L of the extruder can be shortened.

  The screw used in the first kneading section 5 has a right-twisting structure in which the ratio W1 / D of the disk width W1 and the screw major diameter D is 0.45 to 1 and the twist angle is 10 to 30 °. At least one kneading block and a left-twisting kneading block having a ratio W2 / D of the disk width W2 and the major axis D of the screw of 0.1 to 0.3 and a twist angle of 20 to 40 °. It is important to have more than one.

  If the W1 / D of the right twist kneading block is less than 0.45, sufficient shearing force is not applied, the molten state becomes unstable, and this causes a problem of unmelted raw material blowing up at the vent port. On the other hand, if W1 / D exceeds 1, sufficient propulsive force cannot be obtained, the resin stays, and a trouble occurs in which powder enters the supply port 2 and backflows together with air. A preferable value of W1 / D is 0.45 to 0.8. Further, if the twist angle is less than 10 °, the propulsive force is too strong, so that the molten state becomes unstable, causing a problem that the unmelted raw material blows up at the vent port. If it exceeds 30 °, sufficient propulsive force cannot be obtained, and the resin will stay, causing a trouble that powder flows into the supply port 2 and backflows together with air. A preferable value of the twist angle is 15 to 30 °. Here, the disk width W1 is the thickness of the thickest disk among the disks of the kneading block composed of a plurality of disks. In addition, a clearance may be provided in the kneading portion so that the biaxial screw disks in the extruder do not contact each other. In this case, the length including the clearance between the front and rear disks is set to W1. And The same applies to W2.

  If the W2 / D of the left twist kneading block is less than 0.1, the mechanical strength is insufficient and the practicality is lost. On the other hand, if it exceeds 0.3, the filling rate does not increase, and improvement in kneading performance cannot be expected. Also, if the twist angle of the left twist kneading block is less than 20 °, the damming effect of the left twist kneading block will be too great, the resin filling rate will increase, and the powder will be caught in the supply port 2 together with the air Trouble with backflow occurs. When it is larger than 40 °, the damming effect is not sufficient, and the molten state in the kneading part becomes unstable.

  The kneading block with the left twist is preferably installed in the downstream part of the first kneading part. In addition, the number of discs of the left twist kneading block in the downstream portion of the first kneading section is preferably 7 or less, and more preferably 5 or less, in order not to increase the filling rate in the first kneading section.

  In addition, the right twist kneading block, left twist kneading block, neutral kneading block, right twist mixing screw, left twist mixing screw, etc. The screw element used in the kneading part can be additionally used.

  It is important to provide the vent port 9 in the second transport unit 6, and air vented together with the powder material and the volatile matter contained in the powder material can be removed at the vent port. it can. The vent port may be an air vent or a vacuum vent, but when the powder raw material is sucked by the vacuum vent, the air vent can be preferably used.

  As a screw used by the 2nd conveyance part 6, the flight-like screw element normally used for a conveyance part, such as a double thread element and a triple thread element, can be used. Further, the length L / D is preferably 2 to 10, and more preferably 2.0 to 10.0.

  The second kneading part 7 is a part that gives further shearing force to the resin and melts and kneads it, and is a part that is in a proper kneaded state as the thermoplastic resin composition. As with the screw used in the first kneading section 5, a kneading section such as a right twist kneading block, a left twist kneading block, a neutral kneading block, a right twist mixing screw, a left twist mixing screw, etc. Can be used. Further, the length is preferably L / D = 2 to 10, and more preferably 2.0 to 10.0.

  The third transport unit 8 is a part that removes, from the vent port 10, volatile components contained in the powder raw material, volatile components generated by thermal decomposition of the raw material, and the like. As the screw, a flight-like screw element that is usually used for a conveying section, such as a double-thread screw element or a triple-thread screw element, can be used.

  The vent port 10 attached to the third transport unit 8 is preferably a vacuum vent in order to increase the deaeration efficiency. Further, the number of vent ports is not limited to one, and a plurality of vent ports may be provided.

  Further, in order to improve the properties such as mechanical strength of the thermoplastic resin composition, a reinforcing material may be blended. By using the extruder of the present invention, for example, as shown in FIG. It is also possible to apply a side feed method in which a reinforcing material is mixed. In that case, the 1st conveyance part 4 which conveys the powder raw material supplied from the supply port 2, the 1st kneading part 5 which knead | mixes and melt | dissolves at least one part, and the 2nd conveyance part 6 which has the vent port 9 A fourth kneading part 7 for kneading and melting; a third conveying part 8 for conveying the reinforcing material supplied from the supply port 12; a third kneading part 13 for dispersing the reinforcing material; A screw configuration having the conveyance unit 14 can be applied.

  Next, the manufacturing method of the thermoplastic resin composition of this invention is demonstrated using the extruder 1 of FIG.

  The powder raw material supplied from the supply port 2 is conveyed while being melt-kneaded toward the discharge port 11 by heating the extruder barrel and rotating the screw 3. The raw materials are uniformly melt-kneaded in the kneading zone 5 and kneading zone 7 or the kneading zone 13 to form a thermoplastic resin composition. The thermoplastic resin composition is discharged from the discharge port 11 and pelletized by a granulator or sent to a directly connected molding apparatus.

  In the melt kneading production method of the thermoplastic resin composition as described above, the barrel temperature of the extruder is also important, and is set to the melting point temperature of the powder raw material to 350 ° C. or lower, or the glass transition temperature to 350 ° C. or lower. It is preferable to do so. If the barrel temperature is too low, the kneading state of the powder raw material tends to be unstable, while if too high, adverse effects such as thermal decomposition of the resin may occur.

  The method for producing a thermoplastic resin composition of the present invention is particularly suitable for melt kneading of powder raw materials. Here, examples of the powder raw material include a powder resin. Specific examples of the powder resin include polyphenylene sulfide, polyamide resin (nylon 6, nylon 66, etc.), polyester resin (polyethylene terephthalate, polybutylene terephthalate, polybutylene naphthalate, polycarbonate, etc.), polyolefin resin (high density) Polyethylene, low density polyethylene, polypropylene, etc.), polyphenylene ether, polyoxymethylene (polyacetal, etc.), acrylonitrile / butadiene / styrene copolymer, polystyrene, liquid crystal plastic, and the like can be employed. Among these, from the viewpoint of mechanical properties and moldability, a powder raw material containing at least one thermoplastic resin selected from polyphenylene sulfide, polyamide-based resin, and polyester-based resin is preferable. Among these, a powder raw material containing 20 to 100% by weight of polyphenylene sulfide is preferable.

  It is also effective for powder raw materials in which powder resin and powder filler are mixed. As a powder filler, what is conventionally used as a powder filler of a thermoplastic resin composition can be used, and a silicate mineral, a silicate mineral, and various minerals are pulverized by processing such as grinding. Needle-like and granular ones are preferably used. Specific examples include bentonite, dolomite, montmorillonite, barlite, finely divided silicic acid, aluminum silicate, silicon oxide, dosonite, shirasu balloon, clay, sericite, feldspar, talc, calcium carbonate, lithium carbonate, kaolin, zeolite ( (Including synthetic zeolite), talc, mica, synthetic mica and wollastonite (including synthetic wollastonite), glass flakes, glass beads, hydrotalcite and silica.

  In the method for producing the thermoplastic resin composition of the present invention, the powder raw material supplied from the supply port 2 has an apparent density of 0.1 to 0.7 g / ml and / or an average particle size of 1 to 500 μm. It is effective when it is a bulky powder raw material. When the apparent density is 0.1 g / ml or more, the effect of the present invention can be sufficiently achieved, and the dischargeable amount does not decrease. In the case of 0.7 g / ml or less, the effects of the present invention can be sufficiently achieved. Further, when the average particle diameter is 1 μm or more, the effect of the present invention can be sufficiently exerted, and the dischargeable amount does not decrease. When the thickness is 500 μm or less, the effects of the present invention can be sufficiently achieved.

  If at least one of the apparent density and the average particle diameter is in the above range, the effects of the present invention can be achieved. A preferable value of the apparent density is 0.1 to 0.5 g / ml, and a preferable value of the average particle diameter is 1 to 400 μm. In addition, an apparent density says the value measured by the method shown by JISK7365, for example, and an average particle diameter says the value measured by the method shown, for example by JISK5600-9-3.

  Examples of the powder raw material of the thermoplastic resin composition of the present invention include powder raw materials such as the above powder resin and powder filler. In addition to the powder raw material, raw materials such as pellets and fibers are used in combination. May be.

  Moreover, the manufacturing method of the thermoplastic resin composition of this invention can be used conveniently also when supplying an elastomer with a powder raw material from a supply port. Elastomers are mainly used to improve the impact resistance of thermoplastic resin compositions, but sufficient shearing is required to melt the elastomer in the extruder. However, in the usual method, when the powder raw material is supplied into the extruder together with the powder raw material, it is difficult to achieve both the biting of the powder raw material and the melting of the elastomer, so that the discharge amount is greatly reduced and both are not sufficiently melted. It cannot be produced stably. However, when the production method of the present invention is used, a decrease in the discharge amount can be suppressed even when the elastomer is supplied together with the powder raw material. Suppression of the decrease in the discharge amount leads to provision of a thermoplastic resin composition having stable productivity, quality stability, and productivity improvement effect, and cost merit can be expected.

  Although it does not specifically limit as a kind of elastomer, The elastomer optimal for the thermoplastic resin used by this invention, such as a styrene-type elastomer, an olefin-type elastomer, and a urethane-type elastomer, can be selected and used. Specifically, when a polyphenylene sulfide resin is used, an ethylene / glycidyl methacrylate copolymer can be blended as an elastomer as an olefin elastomer.

  The blending amount is preferably 0.1 to 50 parts by weight when 100 parts by weight of one or more thermoplastic resins selected from polyphenylene sulfide, polyamide resin and polyester resin are used. In the case of 0.1 parts by weight or more, the effect of adding an elastomer appears significantly. In the case of 50 parts by weight or less, the effect of the present invention can be sufficiently achieved. Furthermore, there is no possibility that the screw or the barrel and the screw come into contact with each other, and the screw or the barrel is damaged by the elastomer being caught in the screw gap in the single screw portion of the first conveying portion and the screw being shaken. A preferable value of the amount of the elastomer is 1 to 40 parts by weight, and more preferably 1 to 20 parts by weight.

  Further, the reinforcing material can be supplied from the supply port 2 and / or the supply port 12. However, in the case of a material that is easily cut when a strong shearing force is applied, such as a fibrous reinforcing material, it is preferably supplied from the supply port 12. The type of the reinforcing material is not particularly limited, and those conventionally used as reinforcing fibers of thermoplastic resin compositions can be used. Specific examples include glass fibers, carbon fibers, asbestos fibers, carbon fibers, Graphite fiber, metal fiber, potassium titanate whisker, aluminum borate whisker, magnesium-based whisker, silicon-based whisker, slag fiber, gypsum fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber and boron Inorganic reinforcing fiber such as fiber, polyester fiber, nylon fiber, acrylic fiber, regenerated cellulose fiber, acetate fiber, kenaf, ramie, cotton, jute, hemp, sisal, flax, linen, silk, manila hemp, sugar cane, wood pulp, paper waste, Organic reinforcing fibers such as waste paper and wool It is below.

  Furthermore, an additional component can be added from the supply port 2 and / or the supply port 12. For example, a flame retardant, an antioxidant, a weather resistance improver, a release agent, an antistatic agent, a nucleating agent, a coloring agent, and the like can be added.

  Further, in order to prevent the volatile component generated from the raw material such as thermoplastic resin and elastomer in the extruder from being included in the thermoplastic resin composition, when the vent port 10 is a vacuum vent, the degree of vacuum at the vacuum vent port is low. The gauge pressure is preferably −60 kPa or less, and more preferably −80 kPa or less. When the degree of vacuum at the vacuum vent is in the above range, it is possible to efficiently deaerate. Further, the number of vent ports is not limited to one, and a plurality of vent ports may be provided. In that case, the gauge pressure of at least one vent port may be in the above range.

  Next, the effects of the present invention will be specifically described with reference to Examples and Comparative Examples.

  As the extruder, a twin-screw extruder manufactured by Toshiba Machine Co., Ltd. (TEM48, L / D = 48) was used. The extruder has a screw configuration that includes a first conveying unit, two kneading units on the downstream side of the first conveying unit, and two conveying units. Specifically, the extruder 1 shown in FIG. 1 is mentioned. The screw elements used in the first kneading section are as shown in Table 1 below.

  The powder raw material containing the thermoplastic resin and the elastomer were supplied from the supply port 2 at the blending ratio shown in Table 2. A vent port 9 having an air release vent was installed in the second transport unit following the first kneading unit, and a vent port having a vacuum vent was installed downstream of the second kneading unit downstream of the second transport unit. The degree of vacuum of the vacuum vent 10 was -95 kPa as a gauge pressure. The strand-shaped resin composition discharged through the extruder was solidified by cooling with water, and was formed into a thermoplastic resin composition pellet by a granulator.

  In the screw configuration, the length Lc1 of the first transport unit, the length Lc2 of the second transport unit, and the L / D of the length Lm2 of the second kneading unit were set to 12, 12, and 4, respectively. The ratio between the lead length L1 of the single screw element used in the first conveying unit and the screw long diameter D was Ll / D = 1.5, and the total length Lcs1 / D of the single screw was 6.0. A double screw element was disposed downstream of the transition screw element.

  In addition, as shown in Table 2, the element configuration of the first kneading part is changed to change the length Lm1 of the first kneading part and the length Lc3 of the third conveying part by combining various screw elements shown in Table 1. It was.

  The maximum possible discharge amount is such that the screw rotation speed of the extruder is 350 rpm, the temperature of the barrel including the supply port 2 is constant at 50 ° C., and the temperature of the other barrels is constant at 300 ° C. The value obtained by dividing 5 kg / h from the smaller one of the discharge rates at which the vent port 9 blows up at the vent port due to the unmelted resin or unmelted elastomer. The raw materials used in Examples and Comparative Examples are as follows.

(Powder material)
Powder raw material Polyphenylene sulfide (L4230 manufactured by Toray Industries, Inc.) having an apparent density of 0.39 g / ml and an average particle size of 60 μm.
1. Powder raw material Nylon 6 with an apparent density of 0.42 g / ml and an average particle size of 240 μm obtained by freezing and pulverizing CM1001 manufactured by Toray Industries, Inc.
The apparent density was measured by the method shown in JIS K7365, and the average particle size was measured by the method shown in JIS K5600-9-3.

(Elastomer raw material)
Ethylene / glycidyl methacrylate copolymer (E / GMA = 88/12% by weight), MFR = 3 g / 10 min, density 940 kg / m ³ , MFR is a method defined in JIS K6760 (190 ° C., 2160 g load) Measured with

  As can be seen from the results of the maximum possible discharge amount in Table 2, it can be seen that the example has a larger discharge amount and is superior in extrusion efficiency as compared with the comparative example. Further, even when an elastomer was blended in the powder raw material, no decrease in the discharge amount was observed according to the method of the present application.

1: Extruder 2: Supply port 3: Screw 4: First transport unit 5: First kneading unit 6: Second transport unit 7: Second kneading unit 8: Third transport unit 9: Vent port 10: Vent port 11 : Discharge port 12: Second supply port 13: Third kneading unit 14: Fourth transport unit

Claims (4)

A powder raw material extruder having two rotating shafts in the same direction, a first conveying unit to which the powder raw material is supplied, two or more kneading units and two or more conveying units downstream of the first conveying unit The ratio Lc1 / D between the overall length Lc1 of the first conveying unit and the screw major diameter D is 8 to 20, and at least one of the constituent screw elements has a lead length Ll. The ratio Ll / D to the screw major axis D is a single screw element of 0.7-2, and the first kneading part following the first conveying part is a ratio Lm1 / D between the overall length Lm1 and the screw major axis D. 5-12, and has at least one right twist kneading block and one left twist kneading block in its constituent elements, and the right twist kneading block has a disc width W1 and a screw length. The ratio W1 / D to D is 0.45 to 1 and the twist angle is 10 to 30 °, and the left twist kneading block has a ratio W2 / D of the disk width W2 to the screw major axis D of 0.1. To 0.3 and a twist angle of 20 to 40 °, and to a powder raw material extruder having a vent port in the second conveying section following the first kneading section, polyphenylene sulfide, polyamide resin and polyester resin A method for producing a thermoplastic resin composition, comprising supplying a powder raw material having an average particle diameter of 1 to 500 μm containing at least one thermoplastic resin selected from the group consisting of kneading and extruding. 2. The method for producing a thermoplastic resin composition according to claim 1, wherein 0.1 to 50 parts by weight of an elastomer is blended and kneaded and extruded with respect to 100 parts by weight of the thermoplastic resin. The method for producing a thermoplastic resin composition according to claim 1 or 2, wherein a powder raw material having an apparent density of 0.1 to 0.7 g / ml is supplied and kneaded and extruded. In the powder raw material extruder having a vacuum vent on the downstream side of the second kneading unit on the downstream side of the second transport unit, the degree of vacuum at at least one vacuum vent port is −60 kPa or less in terms of gauge pressure. The manufacturing method of the thermoplastic resin composition in any one of Claims 1-3.

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