Method for manufacturing thermoplastic resin composition

Abstract

A method for producing a thermoplastic resin composition includes a kneading step of melt-kneading a bundle of a thermoplastic resin and a fibrous filler in a barrel by using a twin-screw extruder having a pair of screws in the barrel, wherein a premixing step of preliminarily melt-kneading the bundle of the thermoplastic resin and the fibrous filler in the barrel before the kneading step is included, the premixing step is performed in a premixing zone located on an upstream side of a kneading zone in which the kneading step is performed, and a kneading disk is attached to the pair of screws in the premixing zone, a maximum value of a distance between a front end portion of the kneading disk and a position opposite to the front end portion of the kneading disk on an inner wall of the barrel is 1.00 to 4.00 mm.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a thermoplastic resin composition containing fibrous fillers. Background Technology

[0002] Thermoplastic resins, due to their excellent moldability, mechanical properties, and weather resistance, are widely used in various automotive parts, electrical and electronic components, primarily for injection molding. Typically, various additives are added to thermoplastic resins to further improve these properties or compensate for their shortcomings, forming resin compositions. For example, fibrous fillers such as glass fibers are added to improve mechanical strength.

[0003] In manufacturing thermoplastic resin compositions containing fibrous fillers such as glass fibers in a dispersed state, a twin-screw extruder is generally used to melt-blend the thermoplastic resin and the fibrous filler. The fibrous filler is typically produced by coating surface treatment agents, bridging agents, etc., onto fibers used as fillers, then aggregating multiple fibers and cutting them into lengths of a few millimeters. These fibers are then fed into the twin-screw extruder as a bundle (also known as chopped strands). During melt blending, the bundle of fibrous filler is defibrinated, resulting in a state where the fibrous filler is dispersed in the thermoplastic resin (see Patent Document 1).

[0004] However, fibrous filler bundles sometimes remain in an unde-fibered state. Since fibrous filler in an unde-fibered state can cause nozzle clogging during injection molding or lead to reduced strength in molded products, it is desirable for fibrous filler bundles to be fully de-fibered.

[0005] Therefore, various solutions have been proposed as techniques for fully defibrillating fibrous fillers into bundles. Specifically, solutions have been proposed for using reinforced elements, adding elements that impart shear force to the mixing zone in the mixing zone of a twin-screw extruder where thermoplastic resin and fibrous filler bundles are mixed, or changing the ratio Q / Ns when the screw speed is Ns and the extrusion amount of the thermoplastic resin composition is Q (see Patent Documents 2-4).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2022-6931

[0009] Patent Document 2: Japanese Patent No. 5632235

[0010] Patent Document 3: Japanese Patent No. 5536704

[0011] Patent Document 4: Japanese Patent No. 5536705 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] Patent documents 2-4 all employ various methods in the mixing zone of a twin-screw extruder, where thermoplastic resin and fibrous filler bundles are melt-blended, to reduce the amount of unde-fibered fibrous filler bundles. In other words, techniques for fully de-fiberizing the fibrous filler bundles have long been specifically applied to the mixing zone.

[0014] The present invention was made in view of the above-mentioned problems, and its object is to provide a method for manufacturing a thermoplastic resin composition that can fully defibril a bundle of fibrous fillers.

[0015] Technical solutions for solving the problem

[0016] One aspect of the present invention that solves the above-mentioned problems is as follows.

[0017] (1) A method for manufacturing a thermoplastic resin composition, comprising a mixing step, wherein the mixing step involves melt mixing a bundle of thermoplastic resin and fibrous filler in the barrel using a twin-screw extruder having a pair of screws in the barrel, wherein...

[0018] The process includes a premixing step, which, prior to the mixing step, involves pre-melting the thermoplastic resin and the fibrous filler bundles within the cylinder.

[0019] The premixing process is performed in a premixing zone located upstream of the mixing zone where the mixing process is performed.

[0020] A kneading disc is mounted on the pair of screws within the premixing zone.

[0021] The maximum distance between the front end of the kneading disc and the opposite position of the front end of the kneading disc on the inner wall of the cylinder is 1.00 to 4.00 mm.

[0022] (2) The method for manufacturing the thermoplastic resin composition according to (1), wherein the thermoplastic resin is a polyarylene sulfide resin or a polybutylene terephthalate resin.

[0023] (3) The method for manufacturing the thermoplastic resin composition according to (1) or (2), wherein the kneading disc of the premixing zone is an eccentric three-slot kneading disc.

[0024] (4) A method for manufacturing a thermoplastic resin composition according to any one of (1) to (3), wherein the length of the premixed zone is 0.5D to 5.0D.

[0025] Invention Effects

[0026] According to the present invention, a method for manufacturing a thermoplastic resin composition that fully defibrils the bundles of fibrous fillers can be provided. Attached Figure Description

[0027] Figure 1 This is a conceptual diagram illustrating the structure of the twin-screw extruder used in the method for manufacturing the thermoplastic resin composition of this embodiment.

[0028] Figure 2 This is a partial cross-sectional view showing an example of the configuration of the kneading discs (two discs) inside the cylinder of the premixing zone.

[0029] Figure 3 This is a partial cross-sectional view showing an example of the configuration of the kneading discs (three eccentric strips) inside the cylinder of the premixing zone. Detailed Implementation

[0030] The method for manufacturing the thermoplastic resin composition according to this embodiment includes a mixing step in which a bundle of thermoplastic resin and fibrous filler is melt-mixed within a barrel using a twin-screw extruder having a pair of screws within the barrel. It also includes a premixing step in which the bundle of thermoplastic resin and fibrous filler is melt-mixed before the mixing step within the barrel. Furthermore, the premixing step is performed in a premixing zone located upstream of the mixing zone where the mixing step is performed. Moreover, a kneading disc is mounted on the pair of screws within the premixing zone, and the maximum distance between the front end of the kneading disc and the opposing position of the front end of a kneading disc on the inner wall of the barrel is 1.00 to 4.00 mm.

[0031] In the method for manufacturing the thermoplastic resin composition of this embodiment, a twin-screw extruder is used to melt-blend the bundle of thermoplastic resin and fibrous filler. Examples of twin-screw extruders include... Figure 1 The extruder shown has the following structure. Figure 1The twin-screw extruder 10 shown includes: a first feed port 14 for feeding thermoplastic resin into a hopper 12, a plasticizing zone 16, a second feed port 18, a premixing zone 20, a mixing zone 22, and a die section 24. Granular thermoplastic resin fed from the hopper 12 into the first feed port 14 is solidly conveyed to the plasticizing zone 16 and melted. If it is expected that most of the thermoplastic resin will melt, there are no restrictions on the component structure of the plasticizing zone 16. For example, the plasticizing zone can be formed by combining two forward-feeding kneading disc elements with a distance of 0.40 mm between the front ends of two sets of single-sided kneading discs and the inner wall of the barrel, each with a 1.0D (disc thickness 0.2D × 5 pieces, staggered angle 45°) and a reverse-feeding kneading disc element with a distance of 0.40 mm between the front ends of one set of single-sided kneading discs and the inner wall of the barrel.

[0032] The second supply port 18, for example, has a side-feed screw from which a bundle of fibrous fillers such as glass fiber bundles can be supplied to the twin-screw extruder 10.

[0033] The premixing zone 20 is located upstream of the mixing zone 22 and is a zone in which the composition containing the bundle of thermoplastic resin and fibrous filler is pre-melted before being mixed in the mixing zone 22. Premixing is performed to actively contact (wet) the molten or unmolten thermoplastic resin and the bundle of fibrous filler before the melt mixing of the molten resin and the bundle of fibrous filler in the mixing zone 22, so that the bundle of fibrous filler is dispersed to a certain extent uniformly. In other words, in the premixing zone 20, the fiber bundles of fibrous filler are dispersed in the molten thermoplastic resin, and this serves to facilitate the unwinding of the fiber bundles in the mixing zone 22 located downstream.

[0034] The mixing zone 22 is located downstream of the premixing zone 20 and is a region for melt mixing of the composition containing thermoplastic resin and fibrous filler bundles, after premixing. In the mixing zone 22, the fiber bundles of the fibrous filler are defiberized and the fiber length is controlled. At this time, the fiber bundles of the fibrous filler, as described above, are dispersed in the thermoplastic resin through melt mixing in the premixing zone 20, and therefore are easily defiberized in the mixing zone 22.

[0035] In this embodiment, the mixing process is performed in the mixing zone within the barrel of the twin-screw extruder. Furthermore, a premixing process is performed in the premixing zone located upstream of the mixing zone within the barrel of the twin-screw extruder. Additionally, "upstream side" in the twin-screw extruder refers to the side where the thermoplastic resin is fed in.

[0036] In this embodiment, in the premixing zone 20 of a twin-screw extruder 10 having a pair of screws equipped with kneading discs inside the barrel, the maximum distance between the front end of the kneading disc and the opposing position of the front end of the kneading disc on the inner wall of the barrel is 1.00 to 4.00 mm. When this maximum distance is less than 1.00 mm, the amount of the mixture of stressed molten resin and fibrous filler bundles is limited, and good dispersion cannot be ensured in the mixture as a whole. Furthermore, when this maximum distance exceeds 4.00 mm, the amount of the mixture of stressed molten resin and fibrous filler bundles increases, but the applied stress decreases, so the defiberization of the fibrous filler bundles becomes insufficient. The maximum distance is preferably 2.00 to 4.00 mm.

[0037] Reference Figure 2 The kneading disc in the premixing zone 20 will be explained. Figure 2 This illustrates the configuration of kneading discs 34 and 36 mounted on a pair of screws (not shown) within a cylindrical body 32. The cylindrical body 32 is a portion of two overlapping cylindrical sections, each containing a screw. The pair of screws rotate relative to each other within the cylindrical body 32 in the same or opposite directions via a drive mechanism, but the axis of their rotation coincides with the center O of a circle when the cross-section of the cylindrical section is considered circular. The kneading discs 34 and 36 are identical in shape and have a non-symmetrical shape relative to the axis of rotation (the center when the inner walls 38 and 40 of the cylindrical body 32 are considered circular, respectively). More specifically, located in… Figure 2 In the case of the kneading disc 34 on the left side, the distance between the upper front end and the opposing position of the upper front end on the inner wall 38 of the cylinder 32 is d1. The maximum value of this distance d1 is 1.00 to 4.00 mm. On the other hand, the distance between the lower front end of the kneading disc 34 and the opposing position of the lower front end on the inner wall of the cylinder 32 is shorter than the distance d1, for example, less than 0.50 mm. In this way, by separating the front end of the kneading disc 34 from the inner wall 38 of the cylinder 32 by a distance d1, stress can be applied to the entire bundle of fibrous packing in a uniform or nearly uniform state. Conversely, the lower front end is close to the inner wall 38 of the cylinder 32 and has the function of cleaning the inner wall 38 of the cylinder 32 by the rotation of the kneading disc 34. Figure 2 The kneading disc 36 on the right side is the same as the kneading disc 34 on the left side. In addition, the front end of the kneading disc can be completely separated from the inner wall of the cylinder.

[0038] Next, another form of the kneading disc in premixing zone 20 (eccentric three-strip kneading disc) will be described. Regarding the shape of the kneading disc, Figure 3 The form shown is different Figure 2 In the form of. Figure 3This diagram illustrates the configuration of kneading discs 44 and 46 mounted on a pair of screws (not shown) inside the cylinder. The kneading discs 44 and 46 have a roughly equilateral triangular shape with triple rotational symmetry, with point b as the center of symmetry. On the other hand, the rotation axis of the screws, i.e., the rotation center of the kneading discs 44 and 46, is point a, which is located differently from point b, the center of symmetry. In other words, the kneading discs 44 and 46 are mounted to rotate eccentrically relative to the rotation axis of the screws.

[0039] Therefore, in the case of the kneading disc 44, the distance d2 between the opposing positions of the front end and the front ends on the inner wall 48 of the cylinder is constant and does not depend on the rotation of the screw. Furthermore, the maximum value of this distance d2 is 1.00–4.00 mm. Similar to the kneading disc 44 on the left, Figure 3 The distance between the kneading disc 46 on the right side and the opposing positions of the front ends on the inner wall 50 of the cylinder is constant and does not depend on the rotation of the screw.

[0040] Above, refer to Figure 2 and Figure 3 The form of the kneading disc in the premixing zone 20 has been described, but it is not limited to this embodiment. Figure 2 as well as Figure 3 The form is not particularly limited, as long as the maximum distance between the front end of the kneading disc in the premixing zone 20 and the inner wall of the cylinder can be ensured to be 1.00 to 4.00 mm. Common kneading discs, shoulder-cut kneading discs, eccentric kneading discs, etc. are all acceptable.

[0041] The thickness of the kneading disc in the premixing zone 20 is preferably 0.1D to 0.5D, more preferably 0.15D to 0.4D. When the thickness is 0.1D to 0.5D, the strength and durability are sufficient, and enough stress can be applied to the thermoplastic resin through which it passes.

[0042] Furthermore, in this specification, D represents the inner diameter of the cylinder. For example, if the thickness of the kneading disc is expressed as 0.5D, this thickness means 0.5 times the inner diameter of the cylinder.

[0043] The length of the premixing zone 20 is preferably 0.5D to 5.0D, more preferably 1.0D to 4.0D, and even more preferably 1.5D to 4.0D. When the length of the premixing zone 20 is 0.5D to 5.0D, the bundles of fibrous fillers can be sufficiently dispersed in the thermoplastic resin, and the screw length will not become excessively long, which makes it easy to ensure the other zones. Furthermore, if the total length of the zones is 0.5D to 5.0D, the mixing zone can exist alone or can be divided into multiple zones.

[0044] The kneading disc in the premixing zone 20 can be a forward-feeding kneading disc, a reverse-feeding kneading disc, or an orthogonal kneading disc, but from the perspective of residence time and heat generation, a forward-feeding kneading disc is preferred.

[0045] The following shows a preferred example of a kneading disc in the premixing zone 20. However, if the maximum distance between the front end of the kneading disc and the inner wall of the cylinder is within a specified range, a kneading disc different from the example shown below may also be used. Furthermore, the following kneading discs may be used individually or in combination. Additionally, in the following text, the distance between the front end of the kneading disc and the opposite position of the front end of the kneading disc on the inner wall of the cylinder is described as "the distance between the front end and the inner wall of the cylinder".

[0046] (1) Using four sets of 1.0D (disc thickness 0.2D × 5 pieces, staggered angle 45°) positive feed kneading disc elements with a distance of 2.00mm between the front end and the inner wall of the cylinder on both sides, two kneading discs are fed in the positive direction to form a kneading disc of 4.0D length.

[0047] (2) Using a set of two kneading disc elements with a front end distance of 1.0D (disc thickness 0.2D × 5 pieces, staggered angle 45°) that are fed in the positive direction with a distance of 2.00mm on both sides, the kneading discs are formed into a kneading disc of length 1.0D.

[0048] (3) A kneading disc of 3.0D length is formed by using three sets of positive feed eccentric elements with distances of 0.90mm, 3.80mm, and 3.80mm on each side between the front end and the inner wall of the cylinder.

[0049] (4) A kneading disc of 1.0D length (disc thickness 0.2D × 5 pieces, staggered angle 45°) is formed by using three positive feed eccentric elements with a distance of 0.90mm, 3.80mm, and 3.80mm between the front end and the inner wall of the cylinder on each side.

[0050] In this embodiment, from the perspective of improving the dispersion of the fibrous filler bundles, when the screw speed is Ns and the extrusion amount of the thermoplastic resin composition is Q, Q / Ns is preferably 0.5 to 4.0, more preferably 0.6 to 3.0. Furthermore, from the same perspective, the inner diameter of the barrel is preferably 40 to 85 mm.

[0051] On the other hand, the mixing zone 22 is not particularly limited as long as it is a mixing zone with a kneading disc that is commonly used and effective in defiberizing the bundles of fibrous fillers. The kneading disc in the mixing zone 22 can be any of a forward-feed kneading disc, a reverse-feed kneading disc, or an orthogonal kneading disc.

[0052] Specific examples of components in the mixing zone 22 include two kneading discs, three eccentric kneading discs, and a reverse feed screw component with a helical ridge forming multiple slots.

[0053] Hereinafter, the components used in the method for manufacturing the thermoplastic resin composition of this embodiment will be described.

[0054] [Thermoplastic resin]

[0055] In this embodiment, general-purpose plastics and engineering plastics can be used as thermoplastic resins. Examples of thermoplastic resins include polyarylene sulfide resins (PAS), such as polyphenylene sulfide resin (PPS), polybutylene terephthalate resin (PBT), polyacetal resin (POM), liquid crystal polymer (LCP), polyethylene terephthalate resin (PET), polypropylene (PP), and polyamide resin (PA). In this embodiment, polyarylene sulfide resins and polybutylene terephthalate resins are particularly suitable.

[0056] [Fibrous packing]

[0057] Examples of fibrous fillers include glass fiber, carbon fiber, silicon carbide fiber, alumina fiber, silicon carbide whiskers, silicon nitride whiskers, potassium titanate whiskers, and wollastonite. Among these, the manufacturing method of this embodiment is particularly effective when using glass fiber.

[0058] [Other ingredients]

[0059] In this embodiment, one or more general additives for thermoplastic resins may be added as needed, such as lubricants, release agents, antistatic agents, surfactants, flame retardants, or organic polymer materials, inorganic or organic powder or plate-shaped fillers, etc.

[0060] Example

[0061] The following examples will illustrate this embodiment in more detail, but this embodiment is not limited to the following examples.

[0062] [Examples 1-11, Comparative Examples 1-5]

[0063] In each embodiment and comparative example, 100 parts by weight of polyphenylene sulfide resin was fed from the first feeding section and 66.7 parts by weight of glass fiber (fibrous filler) was fed from the second feeding section into the twin-screw extruders (extruder A or B) shown in Tables 1 and 2, and melt-blended under the extrusion conditions (conditions 1 to 4) shown in Table 1 to obtain resin particles. Furthermore, the twin-screw extruder used was... Figure 1In the twin-screw extruders with the structures shown, the premixing zone 20 and the mixing zone 22 in each embodiment and comparative example are as shown in Tables 1 and 2. However, in Comparative Example 1, the premixing zone 20 is not provided, and in Comparative Example 5, the mixing zone 22 is not provided. That is, in Comparative Examples 1 and 5, feeding elements are used instead of kneading elements at the positions of the premixing zone 20 and the mixing zone 22, respectively. Furthermore, the details of the eccentric three or two kneading discs (two KDs) in the premixing zone 20 and a or b in the mixing zone 22 are described below.

[0064] (Extruder)

[0065] Extruder A: TEX44αII (cylinder diameter: 47mm), manufactured by Nippon Steel Corporation.

[0066] Extruder B: TEX65αII (cylinder diameter: 69mm), manufactured by Nippon Steel Corporation.

[0067] (Extrusion conditions)

[0068] (1) Condition 1

[0069] Cylinder temperature: 300℃

[0070] • Extrusion rate per unit time: 150 kg / hr

[0071] Screw speed: 220 rpm

[0072] (2) Condition 2

[0073] Cylinder temperature: 300℃

[0074] • Extrusion rate per unit time: 230 kg / hr

[0075] Screw speed: 338 rpm

[0076] (3) Condition 3

[0077] Cylinder temperature: 300℃

[0078] • Extrusion rate per unit time: 230 kg / hr

[0079] Screw speed: 298 rpm

[0080] (4) Condition 4

[0081] Cylinder temperature: 300℃

[0082] • Extrusion rate per unit time: 400 kg / hr

[0083] Screw speed: 187 rpm

[0084] (Premixed area)

[0085] •Eccentric three-line kneading plate

[0086] One or more forward-feed eccentric triple-row elements of a shape are used with a premixing section length of 3.0D. Furthermore, the maximum distance between the front end of the eccentric triple-row kneading disc and the opposing position of the front end of the eccentric triple-row kneading disc on the inner wall of the cylinder is called the "maximum gap." The same applies to two kneading discs.

[0087] The gaps between the three single-sided tips and the cylinder are 0.90 mm, the maximum gap in the table, and the maximum gap in the table, respectively.

[0088] Component length: 1.0D (disc thickness 0.2D × 5 pieces, staggered angle 45°) / two kneading discs (two KD discs)

[0089] Two kneading elements with one or more shapes are used in a forward feed manner with a premix section length of 3.0D.

[0090] The gap between the tip and the cylinder: both are the largest gaps shown in the table.

[0091] Component thickness: 1.0D (0.2D x 5 pieces, staggered angle 45°)

[0092] (Mix and Match Area)

[0093] a:FK(1.0D)-CK(1.0D)-BK(1.0D)

[0094] b: FK(1.0D)-BMS(2.0D)

[0095] Furthermore, FK, CK, and BK are screw elements composed of two kneading discs with a thickness of 0.2D each. FK represents a forward feed stagger angle of 45 degrees, CK a stagger angle of 90 degrees, and BK a reverse feed stagger angle of 45 degrees. BMS represents a reverse feed screw element with a helical ridge formed by 13 arc-shaped slots. Additionally, the values ​​in parentheses for each element indicate its thickness.

[0096] In addition, the details of each ingredient used are as follows.

[0097] (1) Polyarylene sulfide resin

[0098] PPS resin: Manufactured by KUREHA Corporation, Fortron KPS (melt viscosity: 130 Pa·s, shear rate: 1200 sec) -1 310℃)

[0099] (Determination of melt viscosity of PPS resin)

[0100] The melt viscosity of the above-mentioned PPS resin was determined using the following method.

[0101] Using a capillary apparatus manufactured by Toyo Seiki Co., Ltd. as the capillary, and a flat mold with a diameter of 1 mm and a length of 20 mm, the measurement was conducted at a cylinder temperature of 310°C and a shearing speed of 1200 sec. -1 The melt viscosity below.

[0102] (2) Glass fiber

[0103] Short-cut filaments of glass fiber with a diameter of 10.5 μm and a length of 3.0 mm

[0104] [Table 1]

[0105]

[0106] [Table 2]

[0107]

[0108] [evaluate]

[0109] Evaluation of Unsolved Fiber Count in Glass Fibers

[0110] For the particulate resin compositions obtained in the various examples and comparative examples, the number of undefused glass fibers was counted using the following X-ray CT apparatus (ScanXmate-D090SS270, manufactured by Comscantecno Ltd.) under the following measurement conditions. Specifically, 9g of each resin particle was placed in a sample cell, X-ray CT transmission images were taken, and the number of undefused glass fiber bundles that were highlighted with high brightness was counted. The counting results are shown in Tables 1-2.

[0111] (Measurement conditions)

[0112] Tube voltage: 52kV

[0113] Tube current: 154μA

[0114] Resolution: 26μm / pixel

[0115] As shown in Tables 1-2, in Examples 1-9, the number of undefibrated glass fiber bundles was 0 or 3, indicating that the glass fiber bundles were well defibrated.

[0116] On the other hand, unlike Comparative Example 1 of Examples 1-5, which had too many undefused glass fiber bundles and was not sufficiently defused, only lacking a premixing zone, Comparative Examples 2 and 3, with too small a maximum gap, and Comparative Example 4, with too large a maximum gap, also had too many undefused glass fiber bundles and were not sufficiently defused. Moreover, Comparative Example 5, which did not have a mixing zone, naturally had too many undefused glass fiber bundles and was not sufficiently defused.

[0117] [Examples 12-18, Comparative Examples 6-9]

[0118] In each embodiment and comparative example, the PPS resin was changed to polybutylene terephthalate resin as shown below, 43 parts by weight of glass fiber (fibrous filler) was added to 100 parts by weight of polybutylene terephthalate resin, and the extrusion conditions, premixing elements, maximum gap, length of the premixing zone, and mixing elements were as shown in Tables 3 and 4. Otherwise, resin particles were obtained in the same manner as in Example 1. Furthermore, the undissolved fiber count of the glass fiber was evaluated using the obtained resin particles in the same manner as in Example 1. The evaluation results are shown in Tables 3 and 4.

[0119] (3) Polybutylene terephthalate resin

[0120] PBT resin: Manufactured by Polyplastics Co., Ltd.; PBT resin (intrinsic viscosity (measured in o-chlorophenol at 35°C): 0.8 dL / g)

[0121] [Table 3]

[0122]

[0123] [Table 4]

[0124]

[0125] As shown in Tables 3-4, in Examples 12-18, the number of undefibrated glass fiber bundles was 0-8, indicating that the glass fiber bundles were well defibrated.

[0126] On the other hand, unlike Comparative Example 6 of Examples 12-16, which had too many undefused glass fiber bundles and was not sufficiently defused, only lacking a premixing zone, Comparative Example 7, with its excessively small maximum gap, and Comparative Example 8, with its excessively large maximum gap, both had too many undefused glass fiber bundles and were not sufficiently defused. Furthermore, Comparative Example 9, which did not have a mixing zone, naturally had too many undefused glass fiber bundles and was not sufficiently defused.

[0127] Label Explanation

[0128] 10. Twin-screw extruder

[0129] 12 hoppers

[0130] 14 First Supply Port

[0131] 16 Plasticizing Area

[0132] 18 Second Supply Port

[0133] 20 Premixed Zone

[0134] 22 Mixing Zone

[0135] 24 Mold Department

[0136] 32 Cylinder

[0137] 34 36 44 46 kneading disc

[0138] 38 40 50 Inner wall.

Claims

1. A method for manufacturing a thermoplastic resin composition, comprising a mixing step, said mixing step being performed by melt mixing a bundle of thermoplastic resin and fibrous filler in the barrel using a twin-screw extruder having a pair of screws in the barrel, characterized in that, The process includes a premixing step, which, prior to the mixing step, involves pre-melting the thermoplastic resin and the fibrous filler bundles within the cylinder. The premixing process is performed in a premixing zone located upstream of the mixing zone where the mixing process is performed. A kneading disc is mounted on the pair of screws within the premixing zone. The maximum distance between the front end of the kneading disc and the opposite position of the front end of the kneading disc on the inner wall of the cylinder is 1.00 to 4.00 mm.

2. The method for manufacturing the thermoplastic resin composition according to claim 1, characterized in that, The thermoplastic resin is a polyarylene sulfide resin or a polybutylene terephthalate resin.

3. The method for manufacturing the thermoplastic resin composition according to claim 1 or 2, characterized in that, The kneading disc in the premixing zone is an eccentric three-disc kneading disc.

4. The method for manufacturing the thermoplastic resin composition according to claim 1 or 2, characterized in that, The length of the premixed zone is 0.5D to 5.0D.

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