A stirring and supplying apparatus for fibrous filler, a supplying method, a manufacturing method, and a method for producing a thermoplastic resin composition.

Abstract

To provide a fibrous filler agitation supply device that enables uniform and stable conveyance with a screw even if the fibrous filler is easily spread, has a low bulk density, and tends to aggregate into flocculent forms.SOLUTION: A fibrous filler agitation supply device is a device that feeds the fibrous filler from a hopper containing the fibrous filler to a discharge part, and is equipped with a connection tank between the hopper and the discharge part. A circular inclined surface is provided at a bottom of the connection tank, slanting upward from the bottom of the connection tank, and agitator blades of the circular inclined surface are inclined at an angle Θ of 10° to 70° inward to a direction of rotation of the agitator blades.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a stirring and supply device for fibrous fillers, a supply method, a manufacturing method, and a method for producing thermoplastic resin compositions. [Background technology]

[0002] A common method for manufacturing resin compositions involves supplying various additives along with the raw resin to an extruder, melt-mixing them, and forming resin composition pellets. Fiber-reinforced thermoplastic resin compositions, which incorporate fibrous fillers such as carbon fibers and glass fibers as additives, produce molded articles with high strength and are widely used in various fields.

[0003] To manufacture a fiber-reinforced thermoplastic resin composition, resin pellets of the raw material thermoplastic resin are supplied to an extruder. The resin pellets melt in the extruder cylinder and are fed forward (downstream) by a screw. The fibrous filler is supplied into the cylinder by a side feeder at a predetermined position in the extruder cylinder. Inside the extruder, the molten thermoplastic resin and fibrous filler are kneaded by the rotation of the screw, the fibrous filler is dispersed and cut as needed, and then extruded from the tip nozzle. After cooling and cutting, pellets of the fiber-reinforced thermoplastic resin composition are produced.

[0004] When supplying various additives from a side feeder, the system is equipped with a stirring and supply device consisting of a hopper (metering tank) for containing the raw material additives, a connecting tank below it, an agitator for stirring the raw materials in the connecting tank, and a screw cylinder with a screw at the bottom of the connecting tank for sending the additives to its discharge section.

[0005] Typically, fibrous fillers are supplied as chopped fibers. If such fibrous fillers are supplied directly from a side feeder to an extruder cylinder, the stress on the fibrous fillers during mixing with the thermoplastic resin becomes uneven, making the fibrous fillers prone to breaking or cutting, resulting in a thermoplastic resin composition with an uneven fiber length distribution.

[0006] However, the agitator in conventional agitation and feeding devices stirs the raw material in the connecting tank, and its purpose is to suppress phenomena such as bridging, where the fibrous packing material does not fall out partially or entirely in the connecting tank, or the central part falling out. However, with fibrous packing materials that have a low bulk density and are easily split, it was not possible to stably supply the fibers to the cylinder with a screw. Fibrous packing materials that are easily split easily undergo fiber splitting due to loading into the hopper (metering tank), movement to the bottom, and rotation of the agitator, and they aggregate into a cotton-like substance, failing to fall into the cylinder and forming bridging at the cylinder opening. As a result, the cylinder could not be sufficiently filled with fibrous packing material, making uniform conveyance by the screw difficult. [Overview of the project] [Problems that the invention aims to solve]

[0007] The object (problem) of the present invention is, in view of the problems of the prior art described above, to provide a stirring and supplying device for fibrous fillers and a method for supplying fibrous fillers that enable uniform and stable conveyance by screw, even for fibrous fillers that are prone to fiber opening, have low bulk density, and tend to aggregate into a cotton-like form. Furthermore, the present invention aims to provide a method for producing a fibrous filler in which fiber opening is promoted and bulk density is reduced by the stirring and supplying device or method, and a method for stably producing a thermoplastic resin composition containing the fibrous filler obtained by the production method. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a fibrous packing stirring and supply device, which is a device for feeding fibrous packing from a hopper containing fibrous packing to a discharge section, comprising a connecting tank between the hopper and the discharge section, a circular inclined surface provided at the bottom of the connecting tank extending diagonally upward from the bottom of the connecting tank, a shaft that rotates around a rotation axis protruding inward from the center of the circular inclined surface, and stirring blades for stirring the fibrous packing provided at the tip of the shaft so as to rotate circumferentially on the circular inclined surface, wherein the stirring blades are inclined inward at an angle Θ of 10° to 70° with respect to the direction of rotation of the stirring blades.

[0009] In the above-described stirring and supply device, it is preferable that the shortest distance between the tip of the stirring blade and the inner wall surface of the connecting tank is in the range of 0.2 to 5 cm. Furthermore, it is preferable that the number of stirring blades be 2 to 6. It is preferable to provide a screw at the bottom of the above-mentioned connecting tank for feeding fibrous packing material to the discharge section. Preferably, the area obtained by multiplying the area of ​​the stirring blade by the inclination angle cosΘ is in the range of 0.1 to 1.0 times the opening area of ​​the opening to the screw at the bottom of the connecting tank when viewed from directly above.

[0010] Furthermore, the present invention relates to a method for supplying fibrous packing material, wherein a connecting tank is provided between the hopper and the discharge section, and a circular inclined surface is provided at the bottom of the connecting tank, extending diagonally upward from the bottom of the connecting tank, and a shaft that rotates around a rotation axis protruding inward from the center of the circular inclined surface, and a stirring blade for stirring the fibrous packing material is provided at the tip of the shaft so as to rotate on the circular inclined surface, and the stirring blade is equipped with an agitator that is inclined inward at an angle Θ of 10° to 70° with respect to the rotation direction of the stirring blade, and the fibrous packing material is opened up by the agitator and supplied to the discharge section by a screw provided at the bottom of the connecting tank.

[0011] In the above supply method, it is preferable that the rotational speed of the agitator is 1 to 20% of the rotational speed of the screw. Furthermore, the bulk density V0 of the fibrous packing material contained in the hopper is 0.3~0.7 g / cm³. 3 Therefore, the bulk density V1 of the discharged fibrous filler is less than V0, and is 0.1~0.5 g / cm³. 3 It is preferable that it be within the range.

[0012] Furthermore, the present invention relates to a method for manufacturing fibrous filler, which involves opening the fibers of fibrous filler contained in a hopper to produce fibrous filler with reduced bulk density. The method includes a connecting tank between the hopper and a discharge section, a circular inclined surface provided at the bottom of the connecting tank that extends diagonally upward from the bottom of the connecting tank, a shaft that rotates around a rotation axis protruding inward from the center of the circular inclined surface, and a stirring blade for stirring the fibrous filler, which rotates on the circular inclined surface, the stirring blade being equipped with an agitator that is inclined inward at an angle Θ from 10° to 70° with respect to the rotation direction of the stirring blade, the agitator opening the fibers of the fibrous filler, and supplying it to the discharge section by a screw provided at the bottom of the connecting tank.

[0013] In the above method for manufacturing fibrous filler, the bulk density V0 of the fibrous filler contained in the hopper is 0.3 to 0.7 g / cm³. 3 Therefore, the bulk density V1 of the discharged fibrous filler is less than V0, and is 0.1~0.5 g / cm³. 3 It is preferable that it be within the range.

[0014] The method for producing the thermoplastic resin composition is a method for producing a thermoplastic resin composition by extruding a thermoplastic resin into which a fibrous filler has been blended, characterized in that the fibrous filler, which has a reduced bulk density obtained by the above-mentioned method for producing the fibrous filler, is side-fed from a side feeder provided downstream of the main input port for the raw materials containing the thermoplastic resin, and then melt-kneaded. [Effects of the Invention]

[0015] According to the stirring and feeding device for fibrous filler of the present invention, even for a fibrous filler that is easy to fibrillate, has a low bulk density, and is likely to aggregate in a cotton-like form, uniform and stable conveyance by a screw can be achieved. Further, according to the feeding method of the fibrous filler of the present invention, even for a fibrous filler that is easy to fibrillate and has a low bulk density, stable feeding to the discharge part can be achieved. Moreover, according to the manufacturing method of the fibrous filler of the present invention, a fibrous filler with advanced fibrillation and reduced bulk density can be stably manufactured. Also, according to the manufacturing method of the thermoplastic resin composition of the present invention, a thermoplastic resin composition in which the fibrous filler is uniformly dispersed can be stably manufactured.

Brief Description of the Drawings

[0016] [Figure 1] Fig. 1 is an exploded perspective view showing an embodiment of the stirring and feeding device of the present invention. [Figure 2] Fig. 2 is a partial cross-sectional view of an embodiment of the stirring and feeding device of the present invention. [Figure 3] Figs. 20 are a plan view, a right side view, and a front view showing an embodiment of the stirring blade used in the stirring and feeding device of the present invention.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, the stirring and feeding device, feeding method, manufacturing method, and manufacturing method of the thermoplastic resin composition of the fibrous filler of the present invention will be described with reference to the drawings. The embodiments shown here are merely examples and are not necessarily limited thereto.

[0018] Fig. 1 is an exploded perspective view showing an embodiment of the stirring and feeding device of the present invention. Fig. 2 is a partial cross-sectional view of an embodiment of the stirring and feeding device of the present invention. As shown in Figure 1-2, the stirring and supplying device of the present invention comprises a hopper 1 for containing the introduced fibrous packing material, a connecting tank 2 below the hopper 1, and a screw 5, etc., for supplying the fibrous packing material to the discharge section 3 from an opening 6 at the bottom of the connecting tank 2. The hopper 1 is preferably conical or cylindrical as shown in Figure 1, but may also be prismatic. The connecting tank 2 is connected to the popper 1 at its upper part. The side walls of the connecting tank 2 may be circular in plan view and formed in a conical shape, or they may be elliptical in plan view and have the same or different cross-sectional shapes in the vertical direction. It is also preferable that the side walls of the connecting tank 2 have a cross-sectional shape where the lower side is larger than the upper side.

[0019] Inside the connecting tank 2, a circular inclined surface 11 is provided, extending diagonally upward from the lower part of the connecting tank, preferably the bottom. A shaft 9 rotates around a rotation axis 8 that protrudes diagonally inward from the center of the circular inclined surface 11, and an agitator 4 with stirring blades 10 for stirring the fibrous packing material rotates on the circular inclined surface 11 at the tip of the shaft 9. The fibrous packing material contained in hopper 1 falls into connecting tank 2 by gravity, and is stirred and broken down by the rotation (swirl) of the stirring blade 10 attached to the end of the shaft 9 of agitator 4 along the inclined surface 11.

[0020] Figure 3 shows one embodiment of the stirring blades in the agitator 4, where Figure 3(a) is a top view, Figure 3(b) is a right side view, and Figure 3(c) is a front view. Note that in Figure 3(b), the shafts 9 extending to the left and right and the stirring blades 10 at their ends, as seen in Figure 3(a), are omitted. Also, in Figure 3(c), the shafts 9 extending to the left, right, and rear and the stirring blades 10 at their ends are omitted. The shaft 9 may be formed by two shafts joined together around the rotation axis 8 to create a cross shape, as shown in Figure 3(a), and may have a total of four stirring blades 10. Alternatively, three shafts may intersect and join together around the rotation axis 8, with a total of six stirring blades 10 positioned symmetrically at their ends with the rotation axis 8 as the central point. Three shafts 9 may extend radially from the center of the rotation axis 8 at 120° intervals, each equipped with one stirring blade 10 at its end, for a total of three. A single shaft 9 may also have one stirring blade at each end. The number of stirring blades 10 is preferably 2 to 6.

[0021] The stirring blade 10 is preferably shaped to extend from the shaft 9 upwards towards the inclined surface 11, along the side wall of the connecting tank 2, as shown in Figure 3(b). As shown in Figure 3(c), the stirring blade 10 is inclined at an angle Θ inward, towards the rotation axis 8, with respect to the rotation direction D of the stirring blade 10 (tangential direction of the rotating circumference), and the angle Θ is set to 10° to 70°. By setting the angle in this way, uneven supply from the bottom of the connecting tank 2 to the discharge section 3 is suppressed, and uniform feeding becomes possible. If the angle Θ is less than 10°, the force that sends the fibrous packing material to the cylinder 7 becomes weak, and a sufficient amount of fibrous packing material cannot be filled into the screw 5 for supplying from the bottom of the connecting tank 2 to the discharge section 3, making uniform feeding by the screw difficult. If it is greater than 70°, the force on the rotation axis of the agitator becomes too strong, and the rotation axis is likely to be damaged. More preferably, the angle is in the range of 20° to 60°. The angle Θ is preferably 20° or more, preferably 60° or less, and more preferably 50° or less.

[0022] As shown in Figure 2, the stirring blade 10 rotates along the side wall of the connecting tank 2 on the inclined surface 11, and it is preferable that the shortest distance between the stirring blade 10 and the inner wall surface of the connecting tank be in the range of 0.2 to 5 cm, and more preferably 0.3 to 3 cm. If it is greater than 5 cm, the force pushing the fibrous packing material into the cylinder 7 will be weaker, making it difficult to fill the cylinder 7 with a sufficient amount of fibrous packing material, and uniform feeding by the screw 5 will be difficult. If it is less than 0.2 cm, the stirring blade 10 will come into contact with the inner surface of the hopper, and there is a possibility that the agitator 4 will be damaged.

[0023] The connection tank 2 is preferably circular or elliptical in plan view and conical or elliptical in shape, and the diameter of its inner wall surface is usually 15 to 60 cm, preferably 20 to 50 cm. The diameter of the inclined surface 11 is preferably 15 to 60 cm, more preferably 20 to 50 cm. The length of the shaft 9 from the rotation axis 8 to the stirring blade 10 connection part is preferably 8 to 30 cm, more preferably 10 to 25 cm.

[0024] In the present invention, examples of the fibrous filler include inorganic fibers such as carbon fiber, glass fiber, alumina fiber, boron fiber, and ceramic fiber, and organic fibers such as plant fiber (including kenaf, bamboo fiber, etc.), polyester fiber, aramid fiber, polyoxymethylene fiber, aromatic polyamide fiber, polyparaphenylene benzobisoxazole fiber, and ultra-high molecular weight polyethylene fiber. Among them, carbon fiber and glass fiber are preferable, and carbon fiber is particularly preferable.

[0025] The fibrous filler to be used preferably has a number average fiber length of 20 mm or less, more preferably 10 mm or less, and 1 mm or more. Specifically, chopped fiber and milled fiber are preferable. The bulk density V0 of the raw material fibrous filler accommodated in the hopper is preferably 0.3 to 0.7 g / cm 3 and more preferably 0.35 to 0.65 g / cm 3 and even more preferably in the range of 0.4 to 0.6 g / cm 3 If the bulk density V0 is less than 0.3 / cm 3 it becomes difficult for the stirring blade to push the sufficiently stirred and bulked raw material into the cylinder, and feed non-uniformity is likely to occur. If it exceeds 0.7 g / cm 3 a strong force is applied to the rotation axis of the agitator, and the rotation axis is likely to be damaged. In particular, in the present invention, it is preferable to use a fibrous filler as a raw material that readily undergoes fiber opening and easily increases in volume (decreases in bulk density) upon stirring, as this greatly enhances the effects of the present invention. Examples of fibrous fillers that easily increase in volume upon stirring include fibrous fillers that do not use a consolidator or are treated with only a small amount of such a agent.

[0026] In this invention, bulk density represents the weight of the fibrous filler per unit volume and is the same as loose bulk density, loose bulk density, or loose apparent density. It refers to the bulk density when the filler is lightly and gently filled into a container. The bulk density (V0, V1) is measured according to ISO 60. Specifically, a metal cylinder with a volume of 100 cc and an inner diameter of 50 mm, with a smoothly finished inner surface, is used as the container for filling. The fibrous filler is gently and slowly filled into the container. Once the container is full, the excess material that has risen from the container is scraped off with a straight plate, and the weight of the contents of the container is measured to the nearest 0.1 g to determine the bulk density.

[0027] The fibrous packing material, which has been opened and stirred by the agitator 4, exits through an opening 6 provided at the bottom of the connecting tank 2 and is supplied to the discharge section 3 by a screw 5 for feeding. The opening 6 is located between the bottom of the connecting tank 2 and the inclined surface 11, at a position where the stirring blades 10 push the fibrous packing material from directly above. The screw 5 may be a single-screw or a double-screw configuration. The screw 5 is positioned inside the cylinder 7, and fibrous filler material is filled into the cylinder 7 from the opening 6, causing the screw 5 to rotate and supply the material to the discharge section 3.

[0028] The opening 6 is rectangular in shape, corresponding to the screw 5 directly below it, and the stirring blades 10, with an inclination angle of 10° to 70°, sufficiently push the fibrous packing material from the opening 6 into the cylinder 7, enabling uniform feeding of the fibrous packing material with reduced bulk density.

[0029] The area obtained by multiplying the area of ​​one stirring blade 10 by the inclination angle cosΘ is preferably in the range of 0.1 to 1.0 times the opening area when the opening 6 is viewed from directly above, and more preferably in the range of 0.2 to 0.8 times. If it is less than 0.1 times, the force pushing the fibrous packing material into the cylinder 7 will be weak, making it difficult to fill the cylinder 7 with a sufficient amount of fibrous packing material, and uniform feeding by the screw 5 will be difficult. If it is greater than 1.0 times, the force acting on the agitator 4 will be strong, and the rotating shaft 8 is likely to be damaged. The size of the opening 6 is preferably such that the longer side is about 8-25 cm and the shorter side is about 4-15 cm, resulting in an opening area of ​​35-350 cm². 2 A certain degree is desirable. The area obtained by multiplying the area of ​​one stirring blade 10 by the angle of inclination cosΘ is 5 to 350 cm². 2 A certain degree is desirable.

[0030] The rotational speed of the agitator 4 is preferably 1-20% of the rotational speed of the screw 5, more preferably 2-15%, and even more preferably 3-10%. If it is less than 1%, the amount of fibrous filler that the agitator 4 pushes in will be small, making uniform feeding difficult. If it exceeds 20%, the fibrous filler will open up too much, causing pilling and making it difficult to push into the cylinder 7. As a result, a sufficient amount of fibrous filler cannot be filled into the cylinder 7, making uniform feeding by the screw 5 difficult. The rotational speed of screw 5 is preferably around 10 to 600 rpm, and the rotational speed of agitator 4 is preferably around 2 to 90 rpm.

[0031] The distance a screw advances axially when it makes one rotation is called the "lead." In a single-screw system, the lead and pitch are equal. In a double-screw system, the lead is twice the pitch. If the screw diameter (outer diameter) is D, the lead of screw 5 is preferably 0.5D to 1.5D. If it is greater than 1.5D, the force conveying the fibrous filler weakens, making uniform feeding difficult. If it is less than 0.5D, the conveying force weakens, making uniform feeding difficult. The lead of screw 5 is more preferably 0.6D to 1.4D, and even more preferably 0.7D to 1.3D.

[0032] The bulk density V1 of the fibrous packing material supplied to the discharge section 3 is equal to the bulk density V0 (preferably 0.3 to 0.7 g / cm³) of the fibrous packing material contained in the hopper. 3 It becomes smaller than 0.1-0.5 g / cm³. 3 Preferably, the range is 0.15 to 0.45 g / cm³. 3 Furthermore, 0.2~0.4 g / cm³ 3 A range of [this] is preferred. According to the present invention, even if the raw material is a fibrous filler that has not been treated with a consolidating agent or the like, or has only been treated with a small amount of such an agent, by using the agitator with the above configuration to open the fibers and stir it, then feeding it to the screw 5 and then to the discharge section 3, it is possible to obtain a fibrous filler with a low bulk density as the fibers are opened.

[0033] When the resulting fibrous filler is side-feed into an extruder, a fibrous filler can be obtained that allows for the stable production of a thermoplastic resin composition in which the fibrous filler is uniformly dispersed.

[0034] The thermoplastic resin used as a raw material is not particularly limited to any type, and any thermoplastic resin may be used. Examples of thermoplastic resins suitable for use in the present invention include crystalline thermoplastic resins and amorphous thermoplastic resins. Specifically, examples include polycarbonate resins; polyester resins such as polybutylene terephthalate resin and polyethylene terephthalate resin; styrene resins such as polystyrene resin, high-impact polystyrene resin (HIPS), ABS resin, AES resin, and AS resin; polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resins such as polyamide 6, polyamide 66, and polyamide MXD6; polyoxymethylene resins; polyphenylene sulfide resins; methacrylic resins such as PMMA resin; polyphenylene ether resins; polysulfone resins; polyethersulfone resins; polyarylate resins; polyetherimide resins; polyamideimide resins; polyimide resins; polyetherketone resins; polyetheretherketone resins; polyester carbonate resins; and liquid crystal polymers.

[0035] The extruder can be a single-screw or twin-screw extruder, with a twin-screw extruder being particularly preferred, and it may be vented or not, but a vented extruder is preferred.

[0036] The raw materials, including thermoplastic resin and, if necessary, resin additives, are fed into the extruder cylinder (not shown) in the form of pellets or powder from the main inlet of the hopper at the base of the extruder and transported to the first kneading section. In the first kneading section, the raw materials are heated, with the heating temperature set based on the melting point and glass transition temperature of the main component, the thermoplastic resin. The raw materials, melted and kneaded in the first kneading section, are further pressed by the resin supplied later. The fibrous filler obtained by the stirring and feeding device is then fed into the extruder cylinder from a side feeder located downstream of the main inlet and melted and kneaded in the second kneading section.

[0037] The screw configuration of the kneading section is preferably composed of a combination of two or more elements selected from forward kneading discs, reverse kneading discs, and orthogonal kneading discs.

[0038] The progressive kneading disc element, also known as R-kneading (hereinafter sometimes referred to as R), typically has two or more blades, and it is preferable that the blade twist angle is between 10° and 75°. By setting the blades in this manner with a predetermined angle offset, a pseudo-screw structure is formed, which is the zone where the resin is fed in the feeding direction while a strong shear force is applied, resulting in kneading. The reverse-feed kneading disc element, also known as L-kneading (hereinafter sometimes referred to as L), usually has two or more blades, and it is preferable that the twist angle of the blades is between -10° and -75°. The reverse-feed kneading disc element is an element with the ability to increase pressure by blocking the incoming resin or by working in the direction of sending the incoming resin back. By installing it downstream of the element that promotes kneading, it blocks the resin and exerts a powerful kneading effect. Orthogonal kneading disc elements, also known as N-kneading (hereinafter sometimes referred to as N), typically have two or more blades with a twist angle of 75° to 105°. Because the blades are offset by approximately 90°, the force for dispensing resin is weak, but the kneading force is strong.

[0039] The screw configuration of the first kneading section is preferably composed of a combination of two or more elements, with elements that promote kneading positioned upstream and elements that have a pressure-boosting capacity positioned downstream. Therefore, in the kneading zone of the first step, it is preferable to arrange two or more elements selected from R, N, and L from the upstream side in the order R→N→L, and it is also preferable to arrange multiple instances of each R, N, and L. The screw in the second kneading section is preferably composed of elements selected from a forward kneading disc (R), a reverse kneading disc (L), an orthogonal kneading disc (N), a forward notched mixing screw, and a reverse notched mixing screw.

[0040] The resin composition, which is melt-kneaded in the second mixing section and in which the fibrous filler is sufficiently dispersed, is extruded in a strand shape from the nozzle at the tip of the extruder, cooled, and then cut with a cutter to produce pellets of thermoplastic resin composition. This makes it possible to stably produce thermoplastic resin composition in which the fibrous filler is uniformly dispersed. [Examples]

[0041] First, the following experiment was conducted to determine how much the bulk density of the fibrous filler material increases (or decreases) upon stirring. A Kubota Corporation "Weight-based Screw Feeder CE-W-1 (2-axis)" agitator and feeder (with a hemispherical connection tank having an inner diameter of 25 cm) was used. The agitator was a Kubota Corporation "Agitator 2 for CE-W-1" (centered around a 12.2 cm long rotating shaft extending from the hemispherical side of the connection tank, with a single shaft measuring 22.2 cm in length and 3.2 cm in width, and equipped with two agitator blades measuring 11.8 cm in length and 1.0 cm in tip width, with a rotational inclination angle Θ=0° for vertical rotation). The screw was not connected, and the opening was sealed to allow the agitated fibrous packing material to accumulate. 1 kg of fibrous packing material, whose bulk density V0 was measured before being put into the hopper, was placed in the hopper, and the agitator was rotated at a speed of 1 revolution / second for 15 minutes. After that, the bulk density V1 (bulk density after agitation) was determined. A fibrous filler in which the bulk density V1 after stirring is 0.8 times or less of the bulk density V0 of the raw material is particularly preferred as a raw material to which the present invention is applied.

[0042] For the following raw materials, the bulk density V0 and the bulk density V1 after stirring were determined, and the bulk density ratio (V1 / V0) was calculated. The results were as follows. 1. Mitsubishi Chemical's carbon fiber chopped fiber "DiaLead K6371T" V0: 0.48 g / cm³ 3 V1: 0.31 g / cm³ 3 V1 / V0:0.65 2. Mitsubishi Chemical's carbon fiber chopped fiber "Pyrofil TR06U" V0: 0.47 g / cm³ 3 V1: 0.39 g / cm³ 3 V1 / V0:0.83 3. Nippon Electric Glass Co., Ltd., glass fiber "Chopped Strand T-187" V0: 0.62 g / cm³ 3 V1: 0.54 g / cm³ 3 V1 / V0:0.87 From these results, it can be concluded that "K6371T" is a raw material that increases in volume when stirred.

[0043] [Example 1] As a stirring and feeding device, a conical hopper 1 with a lower diameter of 29 cm, a height of 65 cm, and an upper diameter of 60 cm was used. A connecting tank 2 extended downwards from an upper opening circle with a diameter of 29 cm in a roughly conical shape with a bottom diameter of approximately 40 cm. The bottom of the connecting tank 2 had a circular inclined surface 11 with a diameter of 26 cm, which was angled upwards at a 45° angle from the bottom. As an agitator 4, a shaft 9 that rotates around a rotation axis 8 at the center of the circular inclined surface 11 was used, and stirring blades 10 rotated on the circular inclined surface at the tip of the shaft 9. The length of the shaft 9 was 13 cm from the rotation axis and its width was 2.5 cm. The length of the stirring blades 10 was 10 cm, with a base width of 2.9 cm and a tip width of 2.3 cm. As shown in Figure 3, an agitator (A1) was used with a total of four stirring blades 10 inclined at 30° in the direction of rotation at the tip of the cross-shaped shaft 9. The tip of the stirring blade 10 is positioned so that the closest distance from the inner wall surface of the connecting tank 2 is 0.7 cm. Opening 6 has a long side of 11.0 cm and a short side of 5.5 cm, with an opening area of ​​60.5 cm². 2 The area of ​​one stirring blade 10 is 26.0 cm². 2 The area obtained by multiplying this by the angle of inclination cosΘ (=30°) is 22.5 cm². 2 This is 0.37 times the area of ​​opening 6. The screw 5 inside cylinder 7 was a single-screw with a screw diameter of 25.5 mm (D) and a lead of 26 mm (1.02 D).

[0044] 20 kg of carbon fiber chopped fiber "K6371T" was loaded into hopper 1. The motor ratio of screw 5's rotation speed (agitator rotation speed rpm divided by screw rotation speed rpm) was set to 5%. The discharge rate to discharge section 3 was set to 10 kg / h, and constant weight operation was performed. The discharge rate after 60 to 100 minutes was calculated as follows. After 60 minutes, a container was placed under discharge section 3, and the weight W60 of the carbon fiber discharged over 36 seconds was determined. Next, after 70 minutes, the weight was similarly measured and recorded as W70. Similarly, W80, W90, and W100 were determined. The maximum and minimum values ​​of W from W60 to W100, the difference between the maximum and minimum values, the average value of W over the five measurements, and the rate of change (%, = difference between the maximum and minimum values ​​of W over the five measurements / average value of W over the five measurements) are listed in Table 1 below. 20 kg of carbon fiber chopped fiber "K6371T" discharged into discharge section 3 was recovered, and another 20 kg of "K6371T" was put into hopper 1 and discharged under the same conditions, resulting in a total of 40 kg of "K6371T". The bulk density was measured to be 0.19 g / cm³. 3 That was the case. Thus, it was found that the rotation of the agitator 4 and the screw 5 of the stirring and feeding device of the present invention promotes fiber opening in "K6371T," resulting in a significant decrease in bulk density. This discharged "K6371T" is called "opened fiber K6371T."

[0045] [Example 2] The procedure was the same as in Example 1, except that the agitator (A1) was changed to an agitator (A2) having a total of two stirring blades 10 at both ends of a single shaft 9, each inclined at 30° in the rotational direction. The area of ​​one stirring blade 10 was 26.0 cm². 2 The area obtained by multiplying this by the angle of inclination cosΘ (=30°) is 22.5 cm². 2 This is 0.37 times the area of ​​opening 6.

[0046] [Comparative Example 1] The procedure was the same as in Example 1, except that the agitator 4 was changed to an agitator (AX) having a total of two non-inclined stirring blades 10 at both ends of a single shaft 9.

[0047] The results are shown in Table 1 below. In Table 1, the evaluation was based on the rate of change (difference between the maximum and minimum values ​​of W over 5 trials / average value of W over 5 trials), and was determined according to the following criteria. ◎: Fluctuation rate is 7% or less ○: Fluctuation rate is between 7% and 10%. △: More than 10% ~ 15% or less ×: More than 15%

[0048] [Table 1]

[0049] [Example 1 of manufacturing a thermoplastic resin composition] A twin-screw extruder "TEX44αII" manufactured by Japan Steel Works was used as the extruder. The screw configuration was RRNNL for the first kneading section and RNL for the second kneading section. R represents a progressive kneading disc, N represents an orthogonal kneading disc, and L represents a reverse kneading disc, each using five paddles and 44 mm in length. The cylinder temperature was set to 260°C. As the main raw material, polybutylene terephthalate resin "Novaduran 5008" manufactured by Mitsubishi Engineering Plastics was used and fed at 180 kg / h via a belt feeder to the base of the screw, where it was melted in the first mixing section. A side feed screw was installed between the first and second mixing sections, and carbon fiber chopped fiber "K6371T" obtained by the method of Example 1 was fed at 20 kg / h and mixed in the second mixing section. The screw rotation speed was set to 250 rpm. The strands were removed from the die, cooled in a water tank, cut with a pelletizer, and pellets were obtained. Extrusion was continued for one hour, and the extrusion and strands remained stable with no torque overflow or strand breakage. One g of the pellet was dissolved in a suitable solvent, a phenol / tetrachloroethane = 1 / 1 mixed solvent, and the carbon fibers were filtered and dried, and their weight was measured. The weight of the extracted carbon fibers was 0.096 g (of the 0.1 g of carbon fibers, the carbon content after removing the sizing agent was 0.098 g). From this, it was confirmed that the carbon fiber chopped fiber "K6371T" was fed uniformly.

[0050] [Comparative Example 1 of Thermoplastic Resin Composition Production] In the above manufacturing example 1, the procedure was carried out in the same manner as in comparative example 1, except that the feed of chopped carbon fiber was the same as that obtained in comparative example 1. The torque fluctuation was large, and a torque overload occurred once in one hour, causing the extruder to stop. Also, the strand broke three times. The weight of carbon fiber extracted from 1 g was 0.085 g, which clearly showed that the feed of chopped carbon fiber was fluctuating.

[0051] [Example 2 of manufacturing a thermoplastic resin composition] The thermoplastic resin composition was manufactured in the same manner as in Example 1, except that Mitsubishi Engineering Corporation's polycarbonate resin "Yupilon S3000F" was used as the main raw material and methylene chloride was used as the dissolving solvent. The extrusion and strands were stable, and there was no torque over or strand breakage. The weight of the extracted carbon fiber was 0.096 g, confirming that the carbon fiber chopped fiber K6371T was uniformly fed.

[0052] [Example 3 of manufacturing a thermoplastic resin composition] The process was carried out in the same manner as in Manufacturing Example 1, except that Mitsubishi Gas Chemical Company's polyamide resin "MXD Nylon 6000" was used as the main raw material and hexafluoroisopropanol was used as the solvent. The extrusion and strands were stable, and there were no torque overflows or strand breaks. The weight of the extracted carbon fiber was 0.099 g, confirming that the carbon fiber chopped fiber K6371T was uniformly fed. [Industrial applicability]

[0053] The present invention provides a stirring and supplying apparatus for fibrous fillers, a supplying method, a manufacturing method, and a method for manufacturing a thermoplastic resin composition, which enable uniform and stable conveyance by a screw even for fibrous fillers that are prone to fiber opening and have low bulk density, and enable the stable production of a thermoplastic resin composition in which the fibrous filler is uniformly dispersed. [Explanation of symbols]

[0054] 1: Hoppa 2: Connecting tank 3: Discharge section 4: Agitator 5: Screw 6: Opening 7: Cylinder 8: Rotation axis 9: Shaft 10: Stirring blade 11: Inclined surface

Claims

1. A device for feeding fibrous packing material from a hopper containing fibrous packing material to a discharge section, comprising a connecting tank between the hopper and the discharge section, a circular inclined surface provided at the bottom of the connecting tank extending diagonally upward from the bottom of the connecting tank, a shaft rotating around a rotation axis protruding inward from the center of the circular inclined surface, and a stirring blade for stirring the fibrous packing material provided at the tip of the shaft so as to rotate on the circular inclined surface, wherein the stirring blade is inclined inward at an angle Θ of 10° to 70° with respect to the direction of rotation of the stirring blade.

2. The stirring and supplying device according to claim 1, wherein the shortest distance between the tip of the stirring blade and the inner wall surface of the connecting tank is in the range of 0.2 to 5 cm.

3. The stirring and supplying device according to claim 1, wherein the number of stirring blades is 2 to 6.

4. The stirring and supply device according to claim 1, further comprising a screw at the bottom of the connecting tank for feeding fibrous packing material to the discharge section.

5. The stirring and supplying device according to claim 1, wherein the area obtained by multiplying the area of ​​each stirring blade by the cosΘ of the inclination angle is in the range of 0.1 to 1.0 times the opening area of ​​the opening to the screw at the bottom of the connecting tank as viewed from directly above.

6. A method for supplying fibrous packing material contained in a hopper to a discharge section, wherein a connecting tank is provided between the hopper and the discharge section, a circular inclined surface is provided at the bottom of the connecting tank extending diagonally upward from the bottom of the connecting tank, a shaft that rotates around a rotation axis protruding inward from the center of the circular inclined surface, and a stirring blade for stirring the fibrous packing material is provided at the tip of the shaft so as to rotate on the circular inclined surface, the stirring blade is equipped with an agitator that is inclined inward at an angle Θ of 10° to 70° with respect to the rotation direction of the stirring blade, the fibrous packing material is opened up by the agitator and supplied to the discharge section by a screw provided at the bottom of the connecting tank.

7. The method for supplying fibrous filler according to claim 6, wherein the rotational speed of the agitator is 1 to 20% of the rotational speed of the screw.

8. Bulk density V of the fibrous packing material contained in the hopper ０ 0.3-0.7 g / cm ３ The bulk density V of the discharged fibrous filler is １ is V ０ Even smaller: 0.1–0.5 g / cm ３ A method for supplying a fibrous filler according to claim 6, within the range of [the specified range].

9. A method for producing a fibrous packing material with reduced bulk density by opening the fibers of a fibrous packing material contained in a hopper, wherein a connecting tank is provided between the hopper and a discharge section, a circular inclined surface is provided at the bottom of the connecting tank extending diagonally upward from the bottom of the connecting tank, a shaft that rotates around a rotation axis protruding inward from the center of the circular inclined surface, and a stirring blade for stirring the fibrous packing material is provided at the tip of the shaft so as to rotate on the circular inclined surface, the stirring blade is equipped with an agitator that is inclined inward at an angle Θ from 10° to 70° with respect to the rotation direction of the stirring blade, the fibrous packing material is opened by the agitator and supplied to the discharge section by a screw provided at the bottom of the connecting tank, characterized in that a fibrous packing material with reduced bulk density is produced.

10. The bulk density V of the fibrous filler accommodated in the hopper ０ is 0.3 to 0.7 g / cm ３ and the bulk density V of the discharged fibrous filler １ is V ０ which is smaller than V and in the range of 0.1 to 0.5 g / cm ３ The method for producing a fibrous filler according to claim 9, which is in the range of.

11. A method for producing a thermoplastic resin composition comprising a thermoplastic resin and a fibrous filler by extrusion, characterized in that the fibrous filler, whose bulk density has been reduced by the manufacturing method described in claim 9, is side-fed from a side feeder provided downstream of the main input port for raw materials containing the thermoplastic resin, and then melt-kneaded.

Images