Apparatus and method for manufacturing composite resin compositions

Abstract

The present invention provides a manufacturing apparatus for composite resin compositions with high mechanical strength. [Solution] The apparatus for manufacturing a composite resin composition is a apparatus for kneading raw materials containing a fibrous filler and a thermoplastic resin to manufacture a composite resin composition, comprising: a first rotating body that rotates with respect to a central axis; a second rotating body arranged parallel to the first rotating body and rotating with respect to the central axis to form a kneading section that kneads the raw materials in conjunction with the first rotating body; a first temperature control unit for controlling the temperature of the first rotating body; a second temperature control unit for controlling the temperature of the second rotating body; a first cooling unit for cooling a position on the central axis of the first rotating body that faces the kneading section; and a second cooling unit for cooling a position on the central axis of the second rotating body that faces the kneading section.

Description

Technical Field

[0001] The present invention relates to an apparatus and a method for manufacturing a composite resin composition, and particularly to an apparatus and a method for manufacturing a fibrous filler-containing composite resin composition having excellent mechanical properties.

Background Art

[0002] So-called "general-purpose plastics" such as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) are relatively inexpensive, have a weight that is a fraction of that of metals or ceramics, and are characterized by being easy to process such as molding. Therefore, general-purpose plastics are used as materials for various daily necessities such as bags, various packages, various containers, and sheets, and are also used for industrial parts such as automotive parts and electrical parts, as well as daily necessities and miscellaneous goods.

[0003] However, general-purpose plastics have drawbacks such as insufficient mechanical strength. Therefore, general-purpose plastics do not have sufficient properties required for materials used in various industrial products including mechanical products such as automobiles and electrical, electronic, and information products, and their scope of application is currently limited.

[0004] On the other hand, so-called "engineering plastics" such as polyacetal (POM), polyamide (PA), polycarbonate (PC), and fluororesin have excellent mechanical properties and are used in various industrial products including mechanical products such as automobiles and electrical, electronic, and information products. However, engineering plastics have problems such as being expensive, difficult to monomer recycle, and having a large environmental load.

[0005] Therefore, there is a demand for a significant improvement in the material properties (mechanical strength, etc.) of general-purpose plastics. One known method for improving the material properties of general-purpose plastics is to manufacture composite resins by blending two or more types of resins or additives such as fillers. In particular, fibrous fillers such as natural fibers, glass fibers, and carbon fibers are used with the aim of improving mechanical strength. Among these, organic fibrous fillers such as cellulose have attracted attention in recent years as reinforcing fibers because they are inexpensive and have excellent environmental impact when disposed of.

[0006] However, in order for the mechanical strength-enhancing effect of adding fibrous fillers to function fully, uniform dispersion of the fibrous fillers is required. Fibrous fillers tend to aggregate with each other, making uniform dispersion difficult. In particular, if large aggregates are present, cracks can form starting from the aggregates, making the material prone to cracking and reducing impact strength. Furthermore, aggregation also prevents the elastic modulus-enhancing effect of the fibrous fillers from being fully realized. Therefore, uniform dispersion of fibrous fillers is important in the manufacture of composite resins. Patent document 1 is an example of a manufacturing method that disperses raw materials by kneading. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2011-184520 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, the manufacturing method described in Patent Document 1 has the problem that, because the resin material is continuously heated at a constant temperature during kneading, the high temperature is maintained, the viscosity of the composite resin decreases, shear stress is not applied strongly, and the dispersibility of the raw materials is low, resulting in a decrease in the strength of the composite resin. In addition, because the raw materials are maintained at a high temperature during kneading, the raw materials deteriorate (for example, a decrease in molecular weight, discoloration, etc.).

[0009] The present invention aims to solve the aforementioned conventional problems and to provide a manufacturing apparatus for composite resin compositions with high mechanical strength. [Means for solving the problem]

[0010] The apparatus for producing a composite resin composition according to the present invention is a apparatus for producing a composite resin composition by kneading raw materials containing a fibrous filler and a thermoplastic resin, A first solid of revolution rotating around its central axis, A second rotating body is positioned parallel to the first rotating body and rotates with respect to its central axis to form a mixing section that, together with the first rotating body, mixes the raw materials. A first temperature control unit for controlling the temperature of the first rotating body, A second temperature control unit for controlling the temperature of the second rotating body, A first cooling unit that cools the position opposite the mixing unit, straddling the central axis of the first rotating body, A second cooling section that cools the position opposite the mixing section, straddling the central axis of the second rotating body, It is equipped with.

[0011] The present invention relates to a method for producing a composite resin composition, which involves kneading raw materials containing a fibrous filler and a thermoplastic resin to produce a composite resin composition. The temperature of the first rotating body and the temperature of the second rotating body, which is arranged parallel to the first rotating body and forms a kneading section that kneads the raw materials in conjunction with the first rotating body, are controlled. The position on either side of the central axis of the aforementioned first rotating body, facing the mixing section, and the position on either side of the central axis of the aforementioned second rotating body, facing the mixing section, are cooled. The first rotating body and the second rotating body are rotated, The raw materials are mixed by the aforementioned mixing unit. [Effects of the Invention]

[0012] The apparatus and method for manufacturing composite resin compositions according to the present invention allow for stronger shear force to be applied to the raw materials compared to conventional methods that involve constant heating and kneading, and enable uniform dispersion of additives such as fillers in the resin. As a result, it is possible to produce composite resin compositions with high mechanical strength and other properties in which the effects of additives such as fillers are fully realized. [Brief explanation of the drawing]

[0013] [Figure 1A] This is a schematic plan view showing the configuration of the manufacturing apparatus for the composite resin composition according to Embodiment 1. [Figure 1B] This is a schematic cross-sectional view from the direction aa in Figure 1A. [Figure 2A] This is a schematic side view of another example of a manufacturing apparatus (twin-screw kneader) according to Embodiment 1. [Figure 2B] Figure 2A shows a top view (plan view) of the mixing section of the manufacturing apparatus, with the barrel omitted. [Figure 2C] This is a cross-sectional view taken from the direction bb in Figure 2A. [Figure 3A] This figure shows the change in temperature over time when kneading is performed using a kneading apparatus having a structure in which heating and cooling occur periodically, according to Embodiment 1. [Figure 3B] This figure shows the change in viscosity over time when the mixing is performed using a mixing apparatus having a structure in which heating and cooling occur periodically, according to Embodiment 1. [Figure 3C] This figure shows the change in temperature over time when mixing using a conventional method with a mixing device that is constantly heated. [Figure 3D]It is a diagram showing the change over time of viscosity when kneading by a conventional method using a kneading apparatus that is constantly heated. [Figure 4A] In the cross-sectional view of the kneading section in Embodiment 1, it is an enlarged schematic view locally enlarging the opposing portions of two rotating bodies. [Figure 4B] It is an enlarged schematic view showing the movement of fibrous fillers due to the convection of resin. [Figure 4C] It is an enlarged schematic view showing the state of fibrous fillers before kneading. [Figure 4D] It is an enlarged schematic view showing the state of fibrous fillers during kneading. [Figure 4E] It is an enlarged schematic view showing the state of fibrous fillers after kneading. [Figure 5] It is a diagram showing a table summarizing the measurement results in each of Examples 1 to 4 and Comparative Examples 1 to 12.

Mode for Carrying Out the Invention

[0014] The manufacturing apparatus for a composite resin composition according to the first aspect is a manufacturing apparatus that kneads a raw material containing a fibrous filler and a thermoplastic resin to manufacture a composite resin composition, and a first rotating body that rotates with respect to a central axis, a second rotating body that is arranged parallel to the first rotating body and rotates with respect to the central axis to form a kneading section that kneads the raw material in pair with the first rotating body, a first temperature control section that controls the temperature of the first rotating body, a second temperature control section that controls the temperature of the second rotating body, a first cooling section that cools a position facing the kneading section across the central axis of the first rotating body, a second cooling section that cools a position facing the kneading section across the central axis of the second rotating body, and is provided with.

[0015] The apparatus for manufacturing a composite resin composition according to the second embodiment, in the first embodiment, has a screw shape that moves the raw material from the raw material supply section to the composite resin discharge section along a direction parallel to the central axes of the first and second rotating bodies, The first temperature control unit includes a third temperature control unit for controlling the temperature of the raw material supply section of the first rotating body, and a fourth temperature control unit for controlling the temperature of the composite resin discharge section of the first rotating body. The second temperature control unit may include a fifth temperature control unit for controlling the temperature of the raw material supply section of the second rotating body, and a sixth temperature control unit for controlling the temperature of the composite resin discharge section of the second rotating body.

[0016] In the third embodiment, the apparatus for manufacturing a composite resin composition may, in the first embodiment, have a convex portion and a concave portion on the surface of the first rotating body and the second rotating body, respectively.

[0017] In the fourth embodiment, the apparatus for manufacturing a composite resin composition may, in the third embodiment, have a difference between the distance from the central axis of the apex of the convex portion and the distance from the central axis of the bottom surface of the concave portion that is 0.05% or more and 14% or less with respect to the respective diameters of the first rotating body and the second rotating body.

[0018] A method for producing a composite resin composition according to the fifth embodiment is a method for producing a composite resin composition by kneading raw materials containing a fibrous filler and a thermoplastic resin, The temperature of the first rotating body and the temperature of the second rotating body, which is arranged parallel to the first rotating body and forms a kneading section that kneads the raw materials in conjunction with the first rotating body, are controlled. The position on either side of the central axis of the aforementioned first rotating body, facing the mixing section, and the position on either side of the central axis of the aforementioned second rotating body, facing the mixing section, are cooled. The first rotating body and the second rotating body are rotated, The raw materials are mixed by the aforementioned mixing unit.

[0019] In the sixth embodiment, the method for producing the composite resin composition may involve cooling the position opposite the kneading section with respect to the central axis of the first rotating body and the position opposite the kneading section with respect to the central axis of the second rotating body, such that the temperature difference with respect to the kneading section is 5°C to 80°C.

[0020] In the seventh embodiment, the method for producing a composite resin composition may be used in the fifth embodiment, where the temperature of the first rotating body and the temperature of the second rotating body are controlled such that the temperature difference between the first rotating body and the second rotating body at a position corresponding to the kneading section is 5°C or more and 100°C or less.

[0021] The eighth embodiment of the method for producing a composite resin composition is, in the fifth embodiment, the first rotating body and the second rotating body have a screw shape that moves the raw materials from the raw material input section to the composite resin discharge section along a direction parallel to the central axes of the first rotating body and the second rotating body, At the position corresponding to the mixing section, the temperature of the first rotating body and the temperature of the second rotating body may be controlled such that the temperature of the raw material input section is 5°C to 100°C higher than the temperature of the composite resin discharge section.

[0022] In the method for producing the composite resin composition according to the ninth embodiment, the first rotating body and the second rotating body may be rotated such that the difference in rotational speed is 5% or more and 80% or less, according to any of the fifth to eighth embodiments described above.

[0023] The following describes the manufacturing apparatus and manufacturing method for the composite resin composition according to the embodiment, with reference to the drawings. In the following description, the same reference numerals are used for the same components, and their descriptions are omitted as appropriate.

[0024] (Embodiment 1) Figure 1A is a schematic plan view showing the configuration of a composite resin composition manufacturing apparatus (roll kneader) 10 according to Embodiment 1. Figure 1B is a schematic cross-sectional view taken from the direction aa in Figure 1A. Figure 2A is a side view of another example of a composite resin composition manufacturing apparatus (twin-screw kneader) 10a according to Embodiment 1. Figure 2B is a top view (plan view) of the kneading section 20 of the manufacturing apparatus in Figure 2A, with the barrel omitted. Figure 2C is a cross-sectional view taken from the direction bb in Figure 2A. Here, the kneading section 20 refers to the part where the raw materials are dispersed and mixed. For convenience, in the drawings, the axis direction of the central axis of the rotating bodies 12, 12a, and 12b that constitute the manufacturing apparatus 10, 10a is defined as the x direction, the vertically upward direction is defined as the z direction, and the arrangement direction of the two rotating bodies 12a and 12b is defined as the -y direction.

[0025] In Embodiment 1, the manufacturing apparatus 10, 10a can be a twin-screw kneader, kneader, Banbury mixer, extruder, roll kneader shown in Figures 1A and 1B, or the roll kneader shown in Figures 2A to 2C. Among these, a twin-screw kneader or a roll kneader is more preferable. In the following context, the rotating body of a twin-screw kneader will be treated as a screw, and the rotating body of a roll kneader will be treated as a roll. Note that the manufacturing apparatus 10, 10a only needs to have a rotating body as a kneading means, and is not limited to the above apparatus.

[0026] The manufacturing apparatus 10 shown in Figures 1A and 1B is a roll kneader. As shown in Figure 1A, this manufacturing apparatus 10 has two roll-shaped rotating bodies 12a and 12b facing each other. Specifically, it comprises a rotating body 12a that rotates around a central axis 2a, and a rotating body 12b that is arranged parallel to the rotating body 12a and rotates around a central axis 2b. The two rotating bodies 12a and 12b form a kneading section 20 that kneads the raw materials.

[0027] Furthermore, the composite resin composition manufacturing apparatus 10 includes a first cooling unit 18a that cools the position of the rotating body 12a facing the kneading unit 20, straddling the central axis 2a, and a second cooling unit 18b that cools the position of the rotating body 12b facing the kneading unit 20, straddling the central axis 2b. It also includes a first temperature control unit 19a that controls the temperature of the rotating body 12a, and a second temperature control unit 19b that controls the temperature of the rotating body 12b. Furthermore, the first temperature control unit 19a may include a third temperature control unit 29a that controls the temperature on the upstream side of the rotating body 12a, and a fourth temperature control unit 29b that controls the temperature on the downstream side. Furthermore, the second temperature control unit 19b may include a fifth temperature control unit 29c that controls the temperature on the upstream side of the rotating body 12b, and a sixth temperature control unit 29d that controls the temperature on the downstream side.

[0028] The manufacturing apparatus 10a shown in Figures 2A to 2C is a twin-shaft kneader. As shown in Figure 2A, this manufacturing apparatus 10a comprises a hopper 14 for feeding in raw materials, a raw material supply unit 16 for guiding the raw materials fed from the hopper 14 to the kneading section of the manufacturing apparatus 10a, two rotating bodies 12 that constitute the kneading section, and a barrel 11 that covers the rotating bodies 12.

[0029] As shown in Figures 1A, 1B, and 2B, the kneading section 20 of the manufacturing apparatus 10, 10a is configured between two rotating bodies 12a, 12b arranged parallel to each other. Each rotating body 12a, 12b has a central axis 2a, 2b extending in the x-direction, and kneading discs 3a, 3b provided around the central axis 2a, 2b. Furthermore, the rotating bodies 12a, 12b have fine protrusions 13A and recesses 13B on the surface of the rotating bodies themselves, rather than on the kneading discs. The central axes 2a, 2b are rotated by a motor (not shown). The two rotating bodies 12a, 12b may rotate in the same direction or in different directions. The kneading discs 3a, 3b may also be helical screws aligned with the central axis direction. As a result, the raw materials are kneaded and conveyed in the direction of the rotation axis (x-direction) as the rotating bodies 12a, 12b rotate. In this manufacturing apparatus 10a, the convex portions 13A and concave portions 13B on the surfaces of the two rotating bodies 12a and 12b, which are arranged parallel to each other in the y-direction, face each other via the kneading section 20. Also, as shown in Figure 2B, the section in the rotation axis direction (x-direction) of the two rotating bodies 12a and 12b where raw materials are supplied to the rotating bodies 12a and 12b is defined as the raw material supply section 16. Furthermore, the section from which the composite resin composition is discharged from the rotating bodies 12a and 12b is defined as the composite resin discharge section 17.

[0030] The composite resin composition manufacturing apparatus 10a includes a first cooling section 18a that cools the position of the rotating body 12a facing the kneading section 20, straddling the central axis 2a, and a second cooling section 18b that cools the position of the rotating body 12b facing the kneading section 20, straddling the central axis 2b. Although not shown in Figure 2B, it also includes a first temperature control unit that controls the temperature of the rotating body 12a, and a second temperature control unit that controls the temperature of the rotating body 12b, similar to Figure 1A.

[0031] In this embodiment 1, the temperatures of the two rotating bodies 12a and 12b may decrease as the process progresses from the raw material supply direction to the discharge direction. The two rotating bodies 12a and 12b may have heating sections. Furthermore, it is preferable that the resin is in a molten state during kneading in order for additives, including fibrous fillers, to be uniformly dispersed. For this reason, the raw material supply section 16 in the first half of kneading needs to be at a temperature higher than the softening temperature (melting point) of the resin in order to quickly change the state of the solid resin to a molten state. By making the resin molten, the resin becomes fluid, functions as a solvent, and the uniform dispersion of additives progresses. If the resin does not become molten and remains in a solid state, the solvent will not be fluid, and the dispersion of raw materials will not progress. For this reason, the raw material supply section 16 needs to be at the highest temperature in the kneading section 20. In contrast, in the composite resin discharge section 17 in the second half of kneading, it is preferable that the resin has a high viscosity and that strong shear stress is applied, so it is preferable that the temperature is lower than that of the raw material supply section 16. Furthermore, the composite resin discharge section 17 is preferably at a lower temperature than the raw material supply section 16 in order to smoothly discharge the composite resin composition. If the temperature is too high, the composite resin composition will stick to the rotating bodies 12a and 12b, making smooth discharge impossible. If the temperature is too low, the composite resin composition will adhere to the surfaces of the rotating bodies 12a and 12b, making discharge impossible. Therefore, it is preferable that the temperature of the composite resin discharge section 17, which is at the lowest temperature, has a temperature difference of 5°C to 100°C compared to the temperature of the raw material supply section 16, which is at the highest temperature of the rotating bodies 12a and 12b. Moreover, depending on the raw material, it is even more preferable that the temperature difference between the raw material supply section 16 and the composite resin discharge section 17 be 20°C to 100°C.

[0032] Furthermore, in this embodiment 1, there may be a temperature difference between the two rotating bodies 12a and 12b. For example, if the temperature of rotating body 12a is higher than the temperature of rotating body 12b, rotating body 12b functions as a cooling unit during kneading, preventing the resin temperature from rising due to shear heating. For example, as shown in Figure 1A, the temperature of rotating body 12a may be set higher than the temperature of rotating body 12b by the first temperature control unit 19a and the second temperature control unit 19b. In the following context, rotating body 12a will be treated as being at a higher temperature than rotating body 12b. Also, the existence of a temperature difference between the rotating bodies 12a and 12b causes convection in the resin, promoting the dispersion of raw materials and the defibration of fibrous fillers. To increase the temperature difference between the rotating bodies, it is necessary to make the temperature of rotating body 12a extremely high, the temperature of rotating body 12b extremely low, or both. On the other hand, problems may arise if the temperature difference between rotating bodies 12a and 12b is extremely large. If the temperature is set too high, the raw materials will remain at a high temperature, leading to deterioration of the raw materials (such as a decrease in molecular weight and discoloration). Conversely, if the temperature is set too low, the resin will adhere to the surface of the rotating body 12b, making proper mixing impossible. Therefore, it is preferable that the temperature difference between the two rotating bodies 12a and 12b be between 5°C and 100°C, and even more preferable that the temperature difference be between 5°C and 90°C depending on the raw materials.

[0033] Therefore, the manufacturing apparatus 10, 10a may have a third temperature control unit 29a, a fourth temperature control unit 29b, a fifth temperature control unit 29c, and a sixth temperature control unit 29d in the direction of the central axis of the two rotating bodies 12a, 12b.

[0034] Figures 3A to 3D show the changes in temperature and viscosity over time during the mixing of a composite resin composition. Figure 3A shows the change in temperature over time when mixing is performed using a mixing apparatus having a structure in which heating and cooling occur periodically, according to the mixing method of Embodiment 1. Figure 3B shows the change in viscosity over time when mixing is performed using a mixing apparatus having a structure in which heating and cooling occur periodically, according to the mixing method of Embodiment 1. Figure 3C shows the change in temperature over time when mixing is performed using a conventional method with a mixing apparatus that is constantly heated. Figure 3D shows the change in viscosity over time when mixing is performed using a conventional method with a mixing apparatus that is constantly heated.

[0035] In this embodiment 1, there may be a temperature difference between the kneading section of the manufacturing apparatus 10a and other parts of the resin. As shown in Figures 3A and 3B, in the method for manufacturing the composite resin composition in embodiment 1, cooling and heating occur periodically during kneading, causing the temperature of the composite resin composition to decrease and its viscosity to increase in the cooling section. Due to the high viscosity of the composite resin composition caused by cooling, a large shear stress is applied to the composite resin composition when it is kneaded in the kneading section 20, promoting the dispersion of raw materials and the defibrillation of fibrous fillers. Therefore, in the method for manufacturing the composite resin composition of this embodiment, a composite resin composition with high mechanical strength and uniformly dispersed raw materials can be produced. To increase the temperature difference, it is necessary to make the temperature of one rotating body 12a extremely high, or to make the temperature of the other rotating body 12b extremely low, or both. On the other hand, problems may arise if the temperature difference is extremely large. If the temperature of the rotating body 12a is set too high, the raw materials may deteriorate due to the high temperature (decreased molecular weight, discoloration, etc.), and the reduced viscosity may result in only weak shear stress being applied, preventing the raw materials from being uniformly dispersed. If the temperature of the rotating body 12b is set too low, the temperature may be too low to convert the resin, which has been solidified by the rotating body 12b, into a molten state in the heating section. As a result, instead of kneading, pulverization in a solid state occurs, making it impossible to produce a composite resin composition. Therefore, specifically, it is preferable that the temperature difference between the resins of the rotating body 12a and the rotating body 12b in the kneading section be between 5°C and 80°C, and even more preferable, depending on the raw materials, between 10°C and 80°C.

[0036] In contrast, as shown in Figure 3B, in conventional manufacturing methods, heating is performed continuously, so the temperature of the composite resin composition is maintained at a high temperature, and the viscosity decreases. As a result, sufficient shear stress is not applied, the raw materials are not uniformly dispersed, and exist as aggregates, producing a composite resin composition with low properties such as mechanical strength.

[0037] Furthermore, the deterioration of raw materials (such as a decrease in molecular weight and discoloration) progresses more due to the maintenance of high temperatures for a long period of time than due to instantaneous high temperatures. Therefore, by using the manufacturing method according to this embodiment 1, in which cooling and heating occur periodically with respect to the rotation around the rotating shaft, it is possible to suppress the deterioration of raw materials.

[0038] Specific examples of the structure of a mixing device include a twin-shaft mixer with a pipe for carrying cooling water around the outer circumference of the barrel, and a roll mixer with a blower attached to the rolls so that air is blown locally onto them. The pipe for carrying cooling water around the outer circumference of the barrel and the blower that blows air locally correspond to the cooling section described above.

[0039] Figures 4A to 4E are localized enlarged views of the opposing portions 22 of the two rotating bodies 12a and 12b in the cross-sectional view of the kneading section 20 in Figures 1B and 2C. Figure 4A is an enlarged schematic diagram showing the surface configuration of the rotating bodies 12a and 12b, which have fine irregularities 13A and 13B, facing each other across the kneading section 20. Figure 4B is an enlarged schematic diagram showing the movement of the fibrous filler 26 due to the convection of the resin 24. Figures 4C to 4E show the change in the state of the fibrous filler 26 over time during kneading, with Figure 4C being an enlarged schematic diagram showing the state of the fibrous filler 26 before kneading. Figure 4D is an enlarged schematic diagram showing the state of the fibrous filler 26 during kneading. Figure 4E is an enlarged schematic diagram showing the state of the fibrous filler 26 after kneading.

[0040] As shown in Figures 4A to 4E, it is preferable that the rotating bodies 12a and 12b have fine irregularities 13A and 13B on their surfaces. Due to the presence of these irregularities 13A and 13B, the clearance between the rotating bodies 12a and 12b changes continuously when the rotating bodies 12a and 12b rotate. As a result, the fibrous filler 26 is not constantly subjected to a nearly constant shear stress. When the clearance is wide, the shear stress is small, and when the clearance is narrow, the shear stress is large. When the clearance is narrow, the tip of the fibrous filler 26 is defibrated by the shear stress, but the fibrous filler is held down by the shear stress and further defibration is difficult. However, when the clearance changes from a narrow state to a wide state, the shear stress is relieved and the defibrated tip expands, and when the clearance changes from a wide state to a narrow state, strong shear stress is applied and the crack at the tip expands. Defibration progresses effectively through repeated changes in the width and narrowness of the clearance. Furthermore, the presence of fine irregularities effectively promotes convection, which in turn facilitates the dispersion of raw materials. On the other hand, when using a rotating body with irregularities, if the clearance is too wide, sufficient shear stress will not be applied, and defibration and dispersion will not proceed. Therefore, the appropriate range of irregularities on the surface of the rotating body is calculated by simulation. For example, when the depth of a recess is defined as the distance between the apex of a convex portion 13A and the bottom surface of a concave portion 13B, that is, the distance from the apex of a convex portion 13A to the point of the concave portion 13B furthest from the apex, it is preferable that the surface of the rotating body has recesses with a depth of 0.05% to 14% of the diameter of the rotating body. Furthermore, depending on the raw material, it is preferable to have recesses with a depth of 0.1% to 14%.

[0041] In contrast, when a rotating body without surface irregularities is used, a nearly constant pressure is continuously applied at a microscopic level. This makes it easier for the fibrous filler to maintain a certain shape under pressure, and prevents defibration from progressing.

[0042] In this embodiment 1, it is preferable that the two rotating bodies 12a and 12b have a speed difference. In this case, it is desirable that the rotating body 12a, which is hotter than the rotating body 12b, is moving at a higher speed than the rotating body 12b. Because the rotating body 12a is hotter than the rotating body 12b, the composite resin composition continues to adhere to the side of the rotating body 12b, making it easier to discharge and recover the composite resin composition. Also, because the two rotating bodies 12a and 12b have a speed difference, the opposing surfaces between the rotating bodies 12a and 12b are constantly changing, and the clearance at the narrowest part changes, so that the dispersion of raw materials and the defibration of fibrous fillers proceed efficiently. Specifically, it is preferable that the speed difference between the two rotating bodies 12a and 12b is 5% or more and 80% or less, and it is more preferable that the speed difference between the two rotating bodies 12a and 12b is 30% or more and 80% or less.

[0043] The raw materials in Embodiment 1 consist of at least a thermoplastic resin and a fibrous filler. If the affinity between the thermoplastic resin and the fibrous filler is low, a dispersant may be added.

[0044] In Embodiment 1, the weight ratio of the thermoplastic resin to the fibrous filler is preferably within the range of 95%:5% to 10%:90%. If the weight ratio of the fibrous filler is less than 5%, the amount of filler is insufficient, and therefore improvement in the mechanical properties of the composite resin composition due to the fiber reinforcement effect cannot be expected. If the weight ratio of the fibrous filler is greater than 90%, the amount of resin is insufficient, and therefore a composite resin composition cannot be formed. For this reason, the weight ratio of the thermoplastic resin to the fibrous filler is preferably within the aforementioned range.

[0045] In Embodiment 1, the resin is preferably a thermoplastic resin in order to ensure good performance even after repeated heating and cooling. Examples of thermoplastic resins include olefin resins (including cyclic olefin resins), styrene resins, (meth)acrylic resins, organic acid vinyl ester resins or their derivatives, vinyl ether resins, halogen-containing resins, polycarbonate resins, polyester resins, polyamide resins, thermoplastic polyurethane resins, polysulfone resins (polyethersulfone, polysulfone, etc.), polyphenylene ether resins (polymers of 2,6-xylenol, etc.), cellulose derivatives (cellulose esters, cellulose carbamates, cellulose ethers, etc.), silicone resins (polydimethylsiloxane, polymethylphenylsiloxane, etc.), rubber or elastomers (diene rubbers such as polybutadiene and polyisoprene, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, acrylic rubber, urethane rubber, silicone rubber, etc.). The above resins may be used individually or in combination of two or more. Note that the resin is not limited to the above materials as long as it has thermoplastic properties.

[0046] Of these thermoplastic resins, the resin is preferably an olefin-based resin with a relatively low melting point. Olefin-based resins include homopolymers of olefin-based monomers, copolymers of olefin-based monomers, and copolymers of olefin-based monomers with other copolymerizable monomers. Examples of olefin-based monomers include linear olefins (such as ethylene, propylene, 1-butene, isobutene, 1-pentene, 4-methyl-1-pentene, 1-octene, and other α-C2-20 olefins), and cyclic olefins. These olefin-based monomers may be used individually or in combination of two or more. Among the above olefin-based monomers, linear olefins such as ethylene and propylene are preferred. Other copolymerizable monomers include, for example, vinyl fatty acid esters such as vinyl acetate and vinyl propionate; (meth)acrylic monomers such as (meth)acrylic acid, alkyl (meth)acrylate, and glycidyl (meth)acrylate; unsaturated dicarboxylic acids or their anhydrides such as maleic acid, fumaric acid, and maleic anhydride; vinyl esters of carboxylic acids (e.g., vinyl acetate, vinyl propionate); cyclic olefins such as norbornene and cyclopentadiene; and dienes such as butadiene and isoprene. These copolymerizable monomers may be used alone or in combination of two or more. Specific examples of olefin resins include polyethylene (low-density, medium-density, high-density, or linear low-density polyethylene, etc.), polypropylene, ethylene-propylene copolymers, terpolymers such as ethylene-propylene-butene-1, and copolymers of chain-like olefins (especially α-C2-4 olefins).

[0047] In Embodiment 1, the fibrous filler is used for purposes such as improving mechanical properties, so it is preferable that the fibrous filler has a higher elastic modulus than the resin. Specifically, examples include carbon fiber, carbon nanotubes, pulp, cellulose, cellulose nanofibers, lignocellulose, lignocellulose nanofibers, basic magnesium sulfate fibers (magnesium oxysulfate fibers), potassium titanate fibers, aluminum borate fibers, calcium silicate fibers, calcium carbonate fibers, silicon carbide fibers, wollastonite, xonotlite, various metal fibers, natural fibers such as cotton, silk, wool or hemp, jute fibers, regenerated fibers such as rayon or cupro, semi-synthetic fibers such as acetate and promix, synthetic fibers such as polyester, polyacrylonitrile, polyamide, aramid, and polyolefin, and modified fibers with chemical modifications to their surfaces and ends. Furthermore, among these, carbons and celluloses are particularly preferred from the viewpoint of availability, high elastic modulus, and low coefficient of linear expansion. Furthermore, natural cellulose fibers are preferred from the viewpoint of environmental friendliness.

[0048] Examples of dispersants in Embodiment 1 include various titanate coupling agents, silane coupling agents, unsaturated carboxylic acids, maleic acid, maleic anhydride, or modified polyolefins grafted with the anhydride, fatty acids, fatty acid metal salts, and fatty acid esters. Among the silane coupling agents, unsaturated hydrocarbon-based or epoxy-based ones are preferred. The surface of the dispersant may be treated with a thermosetting or thermoplastic polymer component for modification. The dispersant content of the composite resin molded article in the embodiments of the present invention is preferably 0.01% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 10% by mass or less, and even more preferably 0.5% by mass or more and 5% by mass or less. If the dispersant content is less than 0.01% by mass, poor dispersion may occur. On the other hand, if the dispersant content exceeds 20% by mass, the strength of the composite resin molded article may decrease. The dispersant is appropriately selected depending on the combination of resin and fibrous filler, and it may be omitted if a dispersant is not necessary for the combination.

[0049] In Embodiment 1, an example was described using a roll kneader (Figures 1A and 1B) and a twin-screw kneader (Figures 2A to 2C) as manufacturing equipment. However, other types of kneaders may be used in addition to twin-screw and roll kneaders. [Examples]

[0050] (Example 1) A cellulose fiber-containing composite resin molded article was produced by the following manufacturing method. As mentioned above, kneaders, Banbury mixers, extruders, roll kneaders, etc. can be used as manufacturing equipment, but in this embodiment, a twin-screw kneader was used.

[0051] Polypropylene (product name: BC03B, manufactured by Nippon Polypropylene Co., Ltd.), a block polymer, was used as the thermoplastic resin. Coniferous tree pulp (product name: NBKP Celgar, manufactured by Mitsubishi Paper Mills Ltd.) was used as the fibrous filler. Maleic anhydride-modified polypropylene (product name: Yumex, manufactured by Sanyo Chemical Industries, Ltd.) was used as the dispersant. These materials were weighed in a weight ratio of 80:15:5 and then dry-blended.

[0052] The dry-blended raw materials were supplied to the mixing device at a rate of 2 kg / h using a weight feeder. As described above, the mixing device used was a modified twin-screw mixer (JSW TEX30a) with a cooling water pipe attached to the outside of the barrel, which allowed for periodic heating and cooling. The screw was of the medium-shear type. The composite resin composition discharged from the twin-screw mixer was hot-cut to produce cellulose fiber-containing composite resin pellets.

[0053] Test specimens of composite resin molded products were prepared using injection molding machines (Japan Steel Works 180AD) with the fabricated cellulose fiber-containing composite resin pellets. The conditions for preparing the test specimens were a resin temperature of 190°C, a mold temperature of 60°C, an injection speed of 60 mm / s, and a holding pressure of 80 Pa. The pellets were fed into the molding machine's screw via a hopper, and the rate of penetration was measured by the amount of pellets lost per unit time, confirming that it was constant. The shape of the test specimens was changed according to the evaluation items described below, and a No. 1 size dumbbell was prepared for elastic modulus measurement. In addition, a 60 mm square, 1.2 mm thick flat plate was prepared for drop impact testing. The obtained cellulose fiber-containing composite resin molded product test specimens were evaluated by the following method.

[0054] [Evaluation criteria for composite resin molded products] (Aspect ratio of the unfibrillated portion, length ratio of the fibrillated portion) The obtained cellulose fiber-containing composite resin pellets were immersed in xylene solvent to dissolve the polypropylene, and the shape of the remaining pulp fibers was observed by SEM. Approximately 10 representative fibers were measured, and the fiber diameter was in the range of 2 to 10 μm, and the fiber length was in the range of 200 to 1000 μm. The aspect ratio of the unfibrillated portion (hereinafter sometimes simply referred to as aspect ratio) was approximately 100 to 200. Fibrillated portions were observed at the ends in the fiber length direction, and these fibrillated portions accounted for approximately 30 to 40% of the total fiber length.

[0055] (Specific surface area of ​​fibrous filler) The obtained cellulose fiber-containing composite resin pellets were immersed in xylene solvent to dissolve the polypropylene, and the specific surface area of ​​the remaining cellulose fibers was measured. A specific surface area of ​​less than 150% compared to the raw material was marked with ×, a specific surface area of ​​150% or more but less than 200% was marked with △, and a specific surface area of ​​200% or more was marked with ○. In the composite resin molded article of Example 1, the specific surface area of ​​the cellulose fibers was 210%, and its evaluation was ○.

[0056] (Elastic modulus of composite resin molded articles) Tensile tests were conducted using the obtained dumbbell-shaped specimen No. 1. Here, the elastic modulus was evaluated as follows: values ​​less than 1.8 GPa were marked with ×, values ​​between 1.8 GPa and 2.0 GPa were marked with △, and values ​​of 2.0 GPa or higher were marked with ○. In the composite resin molded article of Example 1, the elastic modulus of the test specimen was 2.3 GPa, and its evaluation was ○.

[0057] (Drop impact strength of composite resin molded body) A drop impact test was conducted using the obtained flat plate-shaped test specimens. Specifically, a 250g weight was dropped from a height of 80cm onto the plate surface of the test specimen to check for cracks. In this evaluation method, a circle (○) was used if no cracks were observed, a triangle (△) was used if cracks were observed only on the surface and the length of the cracks was less than 10mm, and a cross (×) was used if cracks that penetrated the surface were observed or if the length of the cracks was 10mm or longer. In the composite resin molded article of Example 1, no cracks were observed in the test piece, and its evaluation was positive (○).

[0058] (Degree of aggregation of fibrous fillers) The number and size of fibrous filler aggregates were observed using an optical microscope on the obtained flat plate-shaped test specimens. Here, as a method of evaluating the degree of aggregation, a sample with 10 or more aggregates of size 1000 μm or larger in a 10 mm square area was marked with ×, a sample with 3 to 10 aggregates was marked with △, and a sample with fewer than 3 aggregates was marked with ○. In the composite resin molded article of Example 1, the number of 1000 μm aggregates in the test piece was 1, and the evaluation was ○.

[0059] (molecular weight) The molecular weight of cellulose fiber-containing composite resin pellets was measured. If the molecular weight distribution of the composite resin pellets was greater than 20% of that of the raw materials, it was marked as ×; if it was 20% or less, it was marked as ○. In the composite resin molded article of Example 1, the pellets received a positive evaluation.

[0060] (Colorability of composite resin compositions) A coloration test was conducted on cellulose fiber-containing composite resin pellets. If the yellowness (YI value) of the composite resin pellets increased compared to the raw material, it was marked as ×; if it did not increase, it was marked as ○. In the composite resin molded article of Example 1, the pellets received a positive evaluation.

[0061] (Example 2) In Example 2, the temperature difference between the raw material supply section and the composite resin discharge section was changed to 80°C, and cellulose fiber-containing composite resin pellets and molded articles were produced under the same conditions as in Example 1. The same evaluation was also performed as in Example 1.

[0062] (Example 3) In Example 3, the temperature difference between the screws was changed to 70°C, and cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0063] (Example 4) In Example 4, the cooling water flow rate was doubled, and cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0064] (Comparative Example 1) In Comparative Example 1, the temperature from the raw material supply section to the composite resin discharge section was kept constant, while other material and process conditions were the same as in Example 1 to produce cellulose fiber-containing composite resin pellets and molded articles. The evaluation was also performed in the same way as in Example 1.

[0065] (Comparative Example 2) In Comparative Example 2, the temperature difference between the raw material supply section and the composite resin discharge section was changed to 120 degrees Celsius. Cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0066] (Comparative Example 3) In Comparative Example 3, the temperature applied to the two screws was changed to be the same, and cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0067] (Comparative Example 4) In Comparative Example 4, the temperature difference between the two screws was modified to 140°C, and cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0068] (Comparative Example 5) In Comparative Example 5, the mixing equipment was changed to a twin-screw mixer (JSW TEX30a) that was not modified to periodically perform heating and cooling. Cellulose fiber-containing composite resin pellets and molded articles were produced under the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0069] (Comparative Example 6) In Comparative Example 6, the temperature difference between the heating and cooling sections was changed to 135°C, and cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0070] (Comparative Example 7) In Comparative Example 7, the screw was changed to one with no surface irregularities, and cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0071] (Comparative Example 8) In Comparative Example 8, the screw was modified to have surface irregularities with a size of 20% of the screw's major axis. Cellulose fiber-containing composite resin pellets and molded articles were produced under the same material and process conditions as in Example 1. The evaluation was also carried out in the same manner as in Example 1.

[0072] (Comparative Example 9) In Comparative Example 9, the speeds of the two screws were changed to be the same, and cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0073] (Comparative Example 10) In Comparative Example 10, the speed difference between the screws was modified to 100%, and cellulose fiber-containing composite resin pellets and molded articles were produced using the same material and process conditions as in Example 1. The evaluation was also performed in the same manner as in Example 1.

[0074] (Comparative Example 11) In Comparative Example 11, the weight ratio of polypropylene, softwood pulp, and maleic anhydride-modified polypropylene was changed to 98.8:1:0.2. Cellulose fiber-containing composite resin pellets and molded articles were produced under the same material and process conditions as in Example 1. The evaluation was also carried out in the same manner as in Example 1.

[0075] (Comparative Example 12) In Comparative Example 12, the weight ratio of polypropylene, softwood pulp, and maleic anhydride-modified polypropylene was changed to 4:95:1, and cellulose fiber-containing composite resin pellets were prepared in the same manner as in Example 1, except for the material conditions and process conditions.

[0076] The measurement results for each of Examples 1-4 and Comparative Examples 1-12 are shown in the table in Figure 5.

[0077] As is clear from the table in Figure 5, in Example 2, where the temperature difference between the raw material supply section and the composite resin discharge section was changed to 80°C, a larger shear stress was applied to the composite resin discharge section compared to Example 1. As a result, the length ratio of the defibrated portion was 40-50%, and the number of 1000 μm aggregates was 0. Therefore, no cracks were observed even when an impact test was performed at 90 cm. Similar results were obtained in Example 3, where the temperature difference between the two screws was changed to 70°C, and in Example 4, where the temperature difference between the two screws was changed to 50°C. In conclusion, Examples 2, 3, and 4 showed results equivalent to or better than Example 1 in all tests.

[0078] In Comparative Example 1, the temperature from the raw material supply section to the composite resin discharge section was kept constant. In Comparative Example 1, the viscosity at the composite resin discharge section was lower and the shear stress was weaker compared to Example 1, resulting in a length ratio of defibration areas of 10-20%. Consequently, the impact resistance decreased, and the resin cracked in the drop impact test.

[0079] In Comparative Example 2, the temperature difference between the raw material supply section and the composite resin discharge section was changed to 120°C. In this Comparative Example 2, the temperature of the composite resin discharge section was set too low, causing the resin to solidify on the screw and preventing the discharge of the composite resin composition. To conduct the experiment, when the temperature of the composite resin discharge section was set to the minimum temperature required to form the composite resin composition, it was necessary to raise the temperature of the raw material supply section to achieve a temperature difference of 120°C. In this case, however, the temperature was too high, causing a significant decrease in the viscosity of the resin and preventing the production of the composite resin composition.

[0080] In Comparative Example 3, the temperature applied to the two screws was modified to be the same. In this Comparative Example 3, the length ratio of the defibrated portion became 10-20%. As a result, the impact resistance decreased, and the material cracked in the drop impact test.

[0081] In Comparative Example 4, the temperature difference between the two screws was modified to 140°C. In this Comparative Example 4, the temperature of the low-temperature screw was set too low, causing the resin to solidify on the low-temperature screw and preventing the discharge of the composite resin composition. On the other hand, when the temperature of the low-temperature screw was set to the minimum temperature required to form the composite resin composition for the experiment, it was necessary to raise the temperature of the high-temperature roll to achieve a temperature difference of 140°C. In this case, however, the temperature was too high, causing a significant decrease in the viscosity of the resin and making it impossible to produce the composite resin composition.

[0082] In Comparative Example 5, the mixing device was changed to a twin-shaft mixer (JSW TEX30a) that had not been modified to periodically cycle between heating and cooling. In Comparative Example 5, due to the decrease in viscosity caused by the temperature rise due to shear heating, the dispersion of raw materials and the defibration of fibrous fillers did not progress, and the length ratio of the defibrated parts was 10-20%. As a result, the impact resistance decreased, and the product broke in the drop impact test.

[0083] In Comparative Example 6, the temperature difference between the heating and cooling sections was changed to 135°C. In this Comparative Example 6, the temperature of the cooling section was set too low, making it impossible to change the resin, which had been solidified in the cooling section, into a molten state in the heating section. As a result, instead of kneading, pulverization of the solid state occurred, and a composite resin composition could not be produced. When the temperature of the cooling section was changed to a temperature at which the resin could be changed into a molten state in the heating section, and the temperature of the heating section was increased to create a temperature difference of 140°C, the temperature of the heating section became too high, the viscosity of the resin decreased significantly, and a composite resin composition could not be produced.

[0084] In Comparative Example 7, the screw was changed to one with a smooth surface. In this Comparative Example 7, cellulose fibers could not be defibrated in localized areas of the screw surface, resulting in a length ratio of defibrated areas of 10-20%. Consequently, the impact resistance decreased, and the screw cracked during the drop impact test.

[0085] In Comparative Example 8, the screw was modified to have surface irregularities that were 20% of the screw's major axis in size. In this Comparative Example 8, the clearance between the screws became too large, resulting in insufficient shear stress on the raw material, and there were 20-30 aggregates larger than 1000 μm. Consequently, the impact resistance decreased, and the material cracked in the drop impact test.

[0086] In Comparative Example 9, the speeds of the two screws were changed to be the same. In this Comparative Example 9, because the change in clearance was small, the dispersion of the raw materials and the defibrillation of the fibrous filler did not progress, and the length ratio of the defibrillated parts was 20-30%. As a result, the impact resistance decreased, and the material cracked in the drop impact test.

[0087] In Comparative Example 10, the speed difference between the screws was modified to 100%. In this Comparative Example 10, the dispersion of the raw materials and the defibration of the fibrous filler did not progress, and the length ratio of the defibrated parts was 20-30%. As a result, the impact resistance decreased, and the material cracked in the drop impact test.

[0088] In Comparative Example 11, the weight ratio of cellulose fibers was reduced. In this Comparative Example 11, the low amount of cellulose fibers resulted in low viscosity, hindering the dispersion of raw materials and the defibration of fibrous fillers, resulting in a length ratio of defibrated portions of 20-30%. Furthermore, the insufficient amount of cellulose fibers prevented the improvement in the mechanical properties of the composite resin composition due to fiber reinforcement, resulting in a decrease in elastic modulus to 1.4 GPa.

[0089] In Comparative Example 12, the weight ratio of cellulose fibers was increased. In this Comparative Example 12, the amount of resin was extremely small compared to the amount of cellulose fibers, so it was not possible to form a composite resin composition.

[0090] From the above evaluation, it was found that if the temperature difference between the raw material supply section and the composite resin discharge section, the temperature difference applied to the screw, and the temperature difference between the heating section and the cooling section were too large under the process conditions, it was not possible to form a composite resin composition. However, within the range specified in each of the above embodiments (the range in which composite resin composition can be formed), the greater the temperature difference, the greater the shear stress, so the dispersion of raw materials and the defibration of cellulose fibers proceeded effectively, and samples with high elastic modulus and high impact resistance were produced. From the above, it was found that when the cellulose fibers added to the composite resin composition are defibrated, the proportion of the length of the defibrated part of the fiber is long, the aspect ratio of the cellulose fibers is large, the aggregate size is small, and the composite resin composition exhibits high elastic modulus and high impact resistance.

[0091] The method for producing a composite resin composition according to this disclosure is a method for producing a composite resin composition by kneading raw materials, which include at least a fibrous filler and a thermoplastic resin, in a kneading device, The kneading apparatus has two rotating bodies, each of which has a rotating shaft and a convex and concave portion provided around the rotating shaft, and the two rotating bodies are arranged parallel to each other to form a kneading section. The kneading apparatus is characterized by having a heating device in the kneading section that heats at least one of the rotating bodies, setting the surface temperatures of the two rotating bodies to different temperatures, and causing heating and cooling to occur within one rotation around the rotation axis of at least one of the rotating bodies.

[0092] According to the method for producing the composite resin composition described herein, the specific surface area of ​​the fibrous filler after kneading may increase compared to the surface area before kneading.

[0093] The method for producing the composite resin composition according to this disclosure may include a cooling section on the downstream side along the direction of movement of the raw materials parallel to the rotation axis of at least one of the rotating bodies, a heating section on the upstream side, and a temperature difference between the heating section and the cooling section of 5°C or more and 100°C or less.

[0094] In the method for producing the composite resin composition according to this disclosure, the temperature difference between the two rotating bodies may be 5°C or more and 100°C or less.

[0095] The method for producing the composite resin composition according to this disclosure may have a temperature difference of 5°C to 80°C between the resin temperature of the cooling section and the heating section of the kneading apparatus.

[0096] In the method for producing the composite resin composition according to the present disclosure, when the depth of the recess is defined as the distance between the apex of the convex portion and the point on the bottom surface of the recess that is furthest from the apex of the convex portion, the rotating body may be a rotating body having a recess on its surface that has a depth of 0.05% to 14% of the diameter of the rotating body.

[0097] In the method for producing the composite resin composition according to this disclosure, the difference in rotational speed between the two rotating bodies may be 5% or more and 80% or less.

[0098] The method for producing the composite resin composition according to this disclosure may involve preparing the composite resin composition by mixing a thermoplastic resin and a fibrous filler in a mixing ratio ranging from 95%:5% to 10%:90%.

[0099] The composite resin composition kneading apparatus according to this disclosure is a composite resin composition kneading apparatus that kneads raw materials containing at least a fibrous filler and a thermoplastic resin to produce a composite resin composition, Two rotating bodies arranged parallel to each other, each rotating body having a rotation axis and a convex and concave portion provided around the rotation axis, constitute a kneading section. The kneading section is equipped with a heating device for heating at least one of the rotating bodies, A temperature control unit that controls the surface temperatures of the two rotating bodies to be different from each other, It may also be equipped with.

[0100] The kneading apparatus for composite resin compositions according to the present disclosure may have a recess on its surface that has a depth of 0.05% to 14% of the diameter of the rotating body, where the depth of the recess is defined as the distance between the apex of the convex portion and the point on the bottom surface of the recess that is furthest from the apex of the convex portion.

[0101] In the kneading apparatus for the composite resin composition according to this disclosure, the difference in rotational speed between the two rotating bodies may be 5% or more and 80% or less.

[0102] Furthermore, this disclosure includes appropriately combining any of the various embodiments and / or examples described above, and the effects of each embodiment and / or example can be achieved. [Industrial applicability]

[0103] The composite resin composition according to the present invention can provide molded articles with superior mechanical strength compared to conventional general-purpose resins. Because the properties of the resin can be improved by the present invention, it can be used as a substitute for engineering plastics or metal materials. Therefore, it can significantly reduce the manufacturing costs of various industrial products or household goods made of engineering plastics or metals. Furthermore, it can be used in home appliance casings, building materials, and automotive components. [Explanation of symbols]

[0104] 2a, 2b center axis 3a, 3b Mixing discs 10 Manufacturing equipment 11 barrels 12. Solids of revolution 12a Solid of revolution (first solid of revolution) 12b Solids of revolution (second solid of revolution) 13A Convex part 13B Recess 14 Hopper 15 Raw material input port 16. Raw Materials Supply Department 17 Composite resin discharge section 18a First cooling section 18b Second cooling section 19a First temperature control unit 19b Second temperature control unit 20 Mixing section 22 Opposing part 24 resin 26. Fibrous fillers 29a Third temperature control unit 29b Fourth temperature control unit 29c Fifth temperature control unit 29d Sixth temperature control unit

Claims

1. A manufacturing apparatus for kneading raw materials containing fibrous filler and thermoplastic resin to produce a composite resin composition, A first solid of revolution that rotates around its central axis, A second rotating body is positioned parallel to the first rotating body and rotates with respect to its central axis to form a kneading section that kneads the raw materials in conjunction with the first rotating body, A first temperature control unit for controlling the temperature of the first rotating body, A second temperature control unit for controlling the temperature of the second rotating body, A first cooling unit that cools the position opposite the mixing unit, straddling the central axis of the first rotating body, A second cooling section that cools the position opposite the mixing section, straddling the central axis of the second rotating body, A manufacturing apparatus for composite resin compositions, comprising the following features.

2. The first rotating body and the second rotating body have a screw shape that moves the raw material from the raw material supply section to the composite resin discharge section along a direction parallel to the central axes of the first rotating body and the second rotating body, The first temperature control unit includes a third temperature control unit for controlling the temperature of the raw material supply section of the first rotating body, and a fourth temperature control unit for controlling the temperature of the composite resin discharge section of the first rotating body. The second temperature control unit includes a fifth temperature control unit for controlling the temperature of the raw material supply section of the second rotating body, and a sixth temperature control unit for controlling the temperature of the composite resin discharge section of the second rotating body. An apparatus for producing the composite resin composition according to claim 1.

3. The first rotating body and the second rotating body each have a convex portion and a concave portion on their respective surfaces. An apparatus for producing the composite resin composition according to claim 1.

4. The apparatus for producing a composite resin composition according to claim 3, wherein the difference between the distance from the central axis of the apex of the convex portion and the distance from the central axis of the bottom surface of the concave portion is 0.05% or more and 14% or less with respect to the respective diameters of the first rotating body and the second rotating body.

5. A manufacturing method for producing a composite resin composition by kneading raw materials containing fibrous filler and thermoplastic resin, The temperature of the first rotating body and the temperature of the second rotating body, which is arranged parallel to the first rotating body and forms a kneading section that kneads the raw materials in conjunction with the first rotating body, are controlled. The position on either side of the central axis of the first rotating body facing the mixing section and the position on either side of the central axis of the second rotating body facing the mixing section are cooled. The first rotating body and the second rotating body are rotated, A method for producing a composite resin composition, comprising kneading the raw materials in the kneading section.

6. A method for producing a composite resin composition according to claim 5, wherein the position opposite the kneading section with respect to the central axis of the first rotating body and the position opposite the kneading section with respect to the central axis of the second rotating body are cooled such that the temperature difference with respect to the kneading section is 5°C to 80°C.

7. A method for producing a composite resin composition according to claim 5, wherein the temperature of the first rotating body and the temperature of the second rotating body are controlled such that the temperature difference between the first rotating body and the second rotating body at a position corresponding to the mixing section is 5°C or more and 100°C or less.

8. The first rotating body and the second rotating body have a screw shape that moves the raw material from the raw material input section to the composite resin discharge section along a direction parallel to the central axes of the first rotating body and the second rotating body, A method for producing a composite resin composition according to claim 5, wherein the temperature of the first rotating body and the temperature of the second rotating body are controlled such that, at a position corresponding to the kneading section, the temperature of the raw material input section is higher than the temperature of the composite resin discharge section by a range of 5°C to 100°C.

9. A method for producing a composite resin composition according to any one of claims 5 to 8, wherein the first rotating body and the second rotating body are rotated such that the difference in rotational speed is 5% or more and 80% or less.

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