JP2017105081A - Kneading method and kneader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a kneading method and a kneader which manufacture a composite material having high characteristics.SOLUTION: A kneading method includes: a step of introducing a continuous fiber into a kneader; a step of introducing a discontinuous fiber into the kneader; a step of introducing a resin into the kneader; and a step of kneading the continuous fiber, the discontinuous fiber and the resin. A kneader (1) includes: a first introduction section to which a continuous fiber is introduced; a second introduction section to which a discontinuous fiber is introduced; and a kneading shaft (11) that kneads the continuous fiber, the discontinuous fiber and a resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a kneading method and a kneading apparatus, and more particularly to a kneading method and a kneading apparatus for kneading fibers and a resin.

  As a kneading method and a kneading apparatus for kneading fibers and a resin, for example, JP-A-2006-167982 (Patent Document 1) can be mentioned. Patent Document 1 discloses a method for producing long fiber reinforced thermoplastic resin structures having different fiber types in order to compensate for the advantages and disadvantages of the fibers. Specifically, Patent Document 1 discloses that fiber roving is opened by applying tension to fiber roving in a melted thermoplastic resin while pulling the roving of the fiber bundle, impregnated with the thermoplastic resin, and then formed into fibers by a shaping die. In the long fiber reinforced thermoplastic resin structure produced by adjusting the concentration and cooling and cutting into pellets of 3 to 50 mm, a plurality of fiber types are impregnated simultaneously, and each fiber roving is individually separated. It is disclosed that the opening width of each fiber is adjusted to 5 to 40 mm in the impregnation die taken from the outlet.

JP 2006-167982 A

  In Patent Document 1, a long fiber reinforced thermoplastic resin structure having various functions is manufactured using different fibers to be kneaded in a resin. This inventor made it the subject to provide the kneading | mixing method and kneading apparatus which manufacture the composite material which has a high characteristic by a means different from patent document 1. FIG.

  The present inventor considered using recycled fibers as fibers to be kneaded with resin for the purpose of reducing the environmental load. However, unlike the fiber of Patent Document 1, the recycled fiber is not a continuous long fiber but is cut short. The present inventor has shown that in a composite material in which a resin and a fiber are mixed, characteristics such as elastic modulus, strength, and impact resistance greatly depend on the fiber length of the fiber contained in the composite material as shown in FIG. Focused on doing. For example, when the fiber length is 1 mm, the elastic modulus is relatively high, but the impact resistance is inferior. Accordingly, the present inventor has conceived that even when discontinuous fibers having a short fiber length are used, the fibers having a long fiber length are further kneaded in order to improve the impact resistance of the composite material, and the present invention has been completed.

  That is, the kneading method of the present invention includes a step of introducing continuous fibers into the kneading device, a step of introducing discontinuous fibers into the kneading device, a step of introducing resin into the kneading device, continuous fibers, discontinuous fibers, and resin. And a kneading step.

  The kneading apparatus of the present invention includes a first introduction part for introducing continuous fibers, a second introduction part for introducing discontinuous fibers, a kneading shaft for kneading continuous fibers, discontinuous fibers, and a resin. I have.

  According to the kneading method and the kneading apparatus of the present invention, continuous fibers and discontinuous fibers are introduced into the kneading apparatus. A continuous fiber can be made into a fiber having a long fiber length in a composite material produced by kneading with a resin. For this reason, by kneading discontinuous fibers and continuous fibers into a resin, it is possible to disperse fibers having a short fiber length and fibers having a long fiber length in the resin. A fiber having a short fiber length is inferior in impact resistance, but the impact resistance can be supplemented by a fiber having a long fiber length. Therefore, the kneading method and the kneading apparatus of the present invention can produce a composite material having high characteristics even when discontinuous fibers are used.

  In the kneading method and apparatus of the present invention, preferably, the continuous fiber is a glass fiber and the discontinuous fiber is a carbon fiber.

  Glass fiber is advantageous in terms of cost, and is excellent in impact resistance, and carbon fiber is excellent in rigidity (elastic modulus), so it is possible to reduce the cost and to make a composite material that has both excellent rigidity and impact characteristics. Can be manufactured.

  In the kneading method and kneading apparatus of the present invention, preferably, the discontinuous fiber is a recycled fiber. As described above, even if recycled fibers are used, a composite material having high characteristics can be produced.

  In the kneading method of the present invention, preferably, the discontinuous fibers are introduced from a position upstream of the continuous fibers. In the kneading apparatus of the present invention, preferably, the second introduction part is located on the upstream side of the first introduction part.

  Thereby, while the fiber length derived from the continuous fiber contained in a composite material can be lengthened, the dispersibility to the resin of a discontinuous fiber can be improved.

  According to the kneading apparatus and the kneading method of the present invention, a composite material having high characteristics can be produced.

It is a schematic diagram of the kneading apparatus in the embodiment of the present invention. It is a schematic diagram of the pushing-in apparatus in embodiment of this invention. FIG. 5 is a cross-sectional view schematically showing the vicinity of the weir body of the kneading apparatus according to the embodiment of the present invention and taken along the arrow instruction line III-III in FIG. It is a front view which shows roughly the weir body which comprises the kneading apparatus in embodiment of this invention. It is sectional drawing which shows roughly the weir body vicinity of the kneading apparatus in embodiment of this invention, and followed the arrow instruction line VV of FIG. It is a top view of a screw and a rotating shaft which constitute a pushing device in an embodiment of the invention. FIG. 2 is a cross-sectional view schematically showing a kneading state of the kneading apparatus in the embodiment of the present invention and corresponding to the first kneading machine of FIG. 1. It is a graph which shows the characteristic by fiber length in the composite material containing resin and a fiber.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. Further, in the present specification, the direction in which the raw material is introduced (the right side in FIG. 1, the upper side in FIG. 2) is the upstream side, and the direction in which the raw material is discharged (the left side in FIG. 1, the lower side in FIG. 2) is the downstream side. And

  With reference to FIGS. 1-7, the kneading apparatus 1 and the pushing-in apparatus 30 of one Embodiment of this invention are demonstrated. As shown in FIG. 1, a kneading apparatus 1 according to an embodiment of the present invention is an apparatus for producing a composite material by kneading a resin and a fiber, and more specifically, a continuous fiber, a discontinuous fiber, and a resin. Is an apparatus for producing a composite material. Moreover, as shown in FIG. 2, the pushing-in apparatus 30 of embodiment of this invention is an apparatus connected to the 1st kneading machine 10 of the kneading apparatus 1, Comprising: It has a mechanism which raises the bulk density of a discontinuous fiber. Device.

  The continuous fiber is a continuous long fiber, which is a fiber raw material in which the fiber is wound. The continuous fiber is, for example, a roving in which a bundle of a plurality of fibers (for example, 12,000 or more) is wound. The discontinuous fiber is a short cut fiber, and is preferably a recycled fiber. The discontinuous fiber is a fiber recycled from, for example, FRP (fiber reinforced plastic) and has a length of about 0.5 mm to 5 mm. Since the discontinuous fiber is a short fiber, the bulk density is lower than that of the continuous fiber, and much air is brought into the kneading apparatus 1.

  The material of the continuous fiber and the discontinuous fiber is not particularly limited, and carbon fiber, glass fiber, organic fiber, metal fiber, and the like can be used. The continuous fiber and the discontinuous fiber may be the same material or different materials, but are preferably different materials. In the present embodiment, glass fibers advantageous in terms of cost and impact resistance are used as continuous fibers, and carbon fibers advantageous in rigidity (elastic modulus) are used as discontinuous fibers. Specifically, continuous fibers are roving glass fibers and discontinuous fibers are recycled carbon fibers.

  The kneading apparatus 1 includes a first kneading machine 10, a second kneading machine 20, a pushing device 30, and a continuous fiber supply unit 40. The first kneader 10 kneads resin, discontinuous fibers, and continuous fibers. The second kneader 20 kneads and melts the resin introduced into the first kneader 10 prior to kneading with the fibers in the first kneader 10. The pushing device 30 increases the bulk density of the discontinuous fibers introduced into the first kneader 10 and supplies it to the first kneader 10 prior to kneading with the resin in the first kneader 10. The continuous fiber supply unit 40 supplies continuous fibers to the first kneader 10.

<First kneader>
The first kneader 10 includes a kneading shaft 11, a cylinder 12, a drive unit 13a, a speed reducer 13b, a weir body 14, and a die 15.

  The kneading shaft 11 kneads resin and fiber, and includes a screw 11a, a paddle 11b, and a rotating shaft 11c. The first kneader 10 may be a single-shaft kneader having one kneading shaft 11 or a multi-shaft kneader including a plurality of kneading shafts 11. In the present embodiment, The biaxial kneader includes two kneading shafts 11 arranged in parallel to each other. The two rotation shafts 11c are disposed so as to be rotatable in the axial direction, and the rotation directions may be the same or different.

  A screw 11a and a paddle 11b are incorporated in the rotating shaft 11c. The screw 11 a is disposed at the upstream end and the downstream end of the kneading shaft 11, and the paddle 11 b is disposed at the intermediate portion of the kneading shaft 11. The screw 11a and the paddle 11b knead the resin and the fiber by rotating. The screw 11a has a high propulsion function, and the paddle 11b has a high kneading function. The screw 11a and the paddle 11b may be separate members from the rotating shaft 11c, or may be integrally formed with the rotating shaft 11c. Mountains (flights) and valleys (grooves) are formed in the screw 11a.

  In addition, although only the screw 11a may be arrange | positioned at the rotating shaft 11c, since the paddle 11b is arrange | positioned in the intermediate part, since the resin filling rate of the periphery can be raised, the dispersibility of a fiber Can be increased. From this viewpoint, the paddle 11b is preferably a helical paddle and / or a kneading paddle, and is preferably disposed downstream of the discontinuous fiber introduction portion 12b.

  The paddle 11b may include both a helical paddle and a kneading paddle (kneading disc), may include only a helical paddle, may include only a kneading paddle, and may further include other paddles. May be. However, since the gap between the paddle 11b and the cylinder 12 can be sealed with resin by increasing the filling rate, the distance between the discontinuous fiber introduction portion 12b from which the discontinuous fiber is introduced from the pushing device 30 to the paddle 11b. Therefore, it is possible to prevent air from flowing from the first kneader 10 into the pushing device 30 located upstream of the paddle 11b. From this viewpoint, the paddle 11b having a small gap with the cylinder 12 is preferably used. For example, a portion facing the cylinder 12 is a plane extending in the extending direction of the cylinder 12 (except for a spiral shape). Those are preferred. An example of such a paddle is a kneading paddle. Therefore, the paddle 11b preferably includes a kneading paddle, and more preferably includes a plurality of kneading paddles.

  A cylinder 12 is provided to accommodate the two kneading shafts 11 therein. A gap between the cylinder 12 and the kneading shaft 11 becomes a flow path through which resin and / or fiber passes. The cylinder 12 includes a resin introduction portion 12a for introducing the resin supplied from the second kneader 20 into the first kneader 10 and the discontinuous fibers supplied from the pushing device 30 into the first kneader 10. A discontinuous fiber introduction part 12b (second introduction part) for introduction and a continuous fiber introduction part 12c for introducing a plurality of continuous fibers supplied from the continuous fiber supply part 40 into the first kneader 10 (First introduction part). The continuous fiber introduction part 12c may be provided with a cutting part such as a cut flight screw for cutting the continuous fiber, but in this embodiment, the cutting part is omitted and introduced from the continuous fiber supply part 40. The continuous fibers are fed into the first kneader 10 as they are.

  The discontinuous fiber introduction part 12b is located upstream from the continuous fiber introduction part 12c. Moreover, the paddle 11b is arrange | positioned downstream of the discontinuous fiber introduction part 12b, and is promoting that discontinuous fiber is uniformly disperse | distributed to resin. The continuous fiber introduction part 12c is arrange | positioned downstream of the paddle 11b, and is suppressing that a continuous fiber is cut | disconnected shortly.

  In the kneading shaft 11 of the present embodiment, the effective length (L / D) of the length (L) from the bottom of the resin introduction portion 12a to the tip with respect to the diameter (D) of the kneading shaft 11 is, for example, 4 or more and 15 or less. Yes, it is preferably 6 or more and 13 or less.

  A drive unit 13a is connected to one (upstream side) shaft end of the kneading shaft 11 via a speed reducer 13b that distributes torque to the kneading shaft 11. The speed reducer 13b rotates the kneading shaft 11 in synchronization with a predetermined rotational speed.

  A weir body 14 is connected to the other end (downstream side) of the kneading shaft 11. The weir body 14 can be used both as a breaker plate and an intermediate bearing, and is provided in the flow path of the kneaded material. Since the weir body 14 is disposed so as to extend in a direction crossing the flow path of the kneaded material, it applies a back pressure to the kneaded material. The weir body 14 is made of, for example, metal, specifically, special high-strength brass, and the opening through which the kneaded material passes is subjected to wear resistance treatment such as CrN. As shown in FIGS. It is circular.

  As shown in FIGS. 4 and 5, the weir body 14 has a plurality of arc-shaped openings 14 a along the rotation directions of the screws 11 a of the two kneading shafts 11. Thus, the opening 14a is provided corresponding to each kneading shaft 11.

  The opening 14 a has an arc shape centered on the rotating shaft 11 c of the kneading shaft 11. As shown in FIG. 4, each of the openings 14a includes an outer contour line 14a1, an inner contour line 14a2, and a side contour line 14a3 as peripheral edges. The outer contour line 14a1 and the inner contour line 14a2 are concentric arcs. The side contour line 14a3 connects one end and the other end of the outer contour line 14a1 and the inner contour line 14a2.

  As shown in FIG. 3, the outer contour line 14a1 of the opening 14a is an arc along the mountain 11a1 of the screw 11a located on the die 15 side, and the inner contour line 14a2 of the opening 14a is located on the die 15 side. This is an arc along the valley 11a2 of the screw 11a. That is, the outer contour line 14a1 of the opening 14a overlaps with the mountain 11a1 of the downstream screw 11a when viewed from the die 15 side, and the inner contour line 14a2 of the opening 14a is the downstream screw 11a when viewed from the die 15 side. It overlaps with the valley 11a2. In the flow path between the kneading shaft 11 and the cylinder 12, the resin and fiber moving between the crest 11a1 and the trough 11a2 of the screw 11a are greatly affected by the rotation of the screw 11a, and the speed is faster than other regions. . Since the resin and fiber move along the rotation direction of the screw 11a, the outer contour line 14a1 is an arc along the mountain 11a1 of the screw 11a, and the inner contour line 14a2 is an arc along the valley 11a2 of the screw 11a. The propulsive force of the screw 11a can be efficiently transmitted to the kneaded product.

  The length of each outer contour line 14a1 of the opening 14a is preferably 20 mm or more and 50 mm or less, and more preferably 25 mm or more and 40 mm or less. In this case, the passage of unopened fibers of continuous fibers can be prevented.

  As shown in FIGS. 3 and 4, the weir body 14 further includes a through hole 14 b that supports the shaft end portion by inserting the shaft end portion on the downstream side of the kneading shaft 11. When the shaft end of the kneading shaft 11 is fitted into the through hole 14b, the weir body 14 is formed of a wear-resistant material. The wear-resistant material is, for example, a copper-based material such as special high-strength brass. Thus, by supporting the kneading shaft 11 at two points, it is possible to prevent the screw 11a and the body from coming into contact with each other by bending, to reduce the thickness of the screw flight, and to increase the gap between the paddle and the paddle. The fiber breakage due to shearing can be prevented.

  Note that the through hole 14b may be omitted. In this case, the shaft end on the downstream side of the kneading shaft 11 is located on the upstream side of the weir body 14. That is, the weir body 14 is disposed between the die 15 and the kneading shaft 11.

  When the tip of the kneading shaft 11 is located on the downstream side of the weir body 14, as shown in FIG. 5, the weir with respect to the cross-sectional area S1 of the flow path of the resin and fiber located immediately before (upstream side) the weir body 14 The ratio of the area S2 of the opening 14a of the body 14 (S2 / S1) is preferably 48% or more and 69% or less, and more preferably 52% or more and 58% or less. When the tip of the kneading shaft 11 is located on the upstream side of the weir body 14, the opening 14a of the weir body 14 with respect to the cross-sectional area S1 of the resin and fiber flow channel located immediately before (upstream side) the weir body 14 The ratio of the area S2 (S2 / S1) is preferably 35% or more and 50% or less, and more preferably 38% or more and 42% or less. If the upper limit of (S2 / S1) is in this range, unopened fibers can be effectively prevented, and if the lower limit of (S2 / S1) is in this range, pressure loss can be reduced, so that fiber breakage can be prevented. . In addition, the cross-sectional area S1 of the flow path of the resin and the fiber located immediately before the weir body 14 is the weir body from the area projected on the inner surface 12d (see FIGS. 3 and 4) of the cylinder 12 on the weir body 14. 14 is a value obtained by subtracting the area S3 of the kneading shaft 11 in contact with the surface opposite to the die 15. When the tip of the kneading shaft 11 is located on the upstream side of the weir body 14, the area of the kneading shaft 11 in contact with the surface of the weir body 14 opposite to the die 15 is zero. The area S2 of the opening 14a is the total area of the plurality of openings 14a.

  As shown in FIGS. 4 and 5, two openings 14a of the present embodiment are formed around two kneading shafts 11, respectively, but the number of openings 14a is the number of screws 11a. It can be arbitrarily selected depending on the size. For example, when the screw 11a is larger than FIG. 4, for example, four or more each may be formed around the two kneading shafts 11.

  As shown in FIGS. 1 and 3, a die 15 is provided on the weir body 14 on the side opposite to the screw 11a. The die 15 has a discharge port 15a for discharging the composite material.

<Second kneader>
As shown in FIG. 1, the resin introduced into the resin introduction portion 12 a of the cylinder 12 of the first kneader 10 described above is previously melted in the second kneader 20. The second kneader 20 includes a kneading shaft 21 having a screw 21 a, a cylinder 22, a drive unit 23 a, a speed reducer 23 b, and a hopper 24. The second kneader 20 may be a single-screw kneader having one kneading shaft 21 or may be a multi-shaft kneader including a plurality of kneading shafts 21. As for the kneading shaft 21, only the screw 21a may be incorporated in the rotating shaft 21b, or a paddle may be incorporated in the middle portion instead of the screw. The screw (a screw and a paddle when including a paddle) may be a separate member from the rotating shaft 21b, or may be integrally formed with the rotating shaft 21b. The cylinder 22 has a discharge port 22 a for supplying the molten resin to the first kneader 10. The drive unit 23a and the speed reducer 23b rotate the kneading shaft 21 at a predetermined rotation speed. The hopper 24 receives a resin raw material 50 kneaded between the kneading shaft 21 and the cylinder 22.

<Indentation device>
As shown in FIG. 1, the pushing device 30 supplies the discontinuous fibers introduced into the discontinuous fiber introduction portion 12 b of the cylinder 12 of the first kneader 10 described above. That is, the pushing device 30 is connected so as to communicate with the discontinuous fiber introducing portion 12b of the first kneader 10. The pushing device 30 is configured to be detachable from the first kneader 10.

  As shown in FIG. 2, the pushing device 30 includes a transport unit 31, a casing 32, a rotating shaft 33, a screw 34, a filter 35, a drive unit 36, and a speed reducer 37.

  The conveyance unit 31 conveys the discontinuous fiber to the casing 32. A casing 32 is connected to the transport unit 31, and discontinuous fibers are introduced into the casing 32. In the casing 32, the rotating shaft 33 is arrange | positioned so that it may extend along the moving direction of a discontinuous fiber.

  A screw 34 is incorporated in the rotating shaft 33. The screw 34 may be a separate member from the rotating shaft 33 or may be integrally formed with the rotating shaft 33.

  The screw 34 is formed with a mountain (flight) and a valley (groove). The uppermost end of the screw 34 is positioned below the connection portion with the transport unit 31 into which the discontinuous fibers of the casing 32 are introduced.

  The pitches P1 to P5 of the screw 34 decrease from the upstream side toward the downstream side. Here, “decreasing” means that the pitches P1 to P5 of the screw 34 are always the same or decreasing from the upstream side toward the downstream side (in the direction in which the discontinuous fibers move), and the most upstream. This means that the most downstream pitch is smaller than this pitch. That is, “decreasing” does not include a portion increasing from the upstream side toward the downstream side. Further, the pitches P1 to P5 of the screw 34 are the length of one round of the mountain in the direction from the upstream side to the downstream side. For example, the pitches P1 and P2 are 60 mm, and the pitches P3 to P5 are 40 mm.

  The outer diameter of the screw 34 decreases from the upstream side toward the downstream side. Here, “decreasing” means that the outer diameter of the screw 34 is always the same or decreasing from the upstream side toward the downstream side (in the direction in which the discontinuous fibers move), and is located at the most upstream position. This means that the outer diameter located on the most downstream side is smaller than the outer diameter. That is, “decreasing” does not include a portion increasing from the upstream side toward the downstream side.

  Further, as shown in FIG. 6, a notch 34 a is formed at the upstream end of the screw 34. In the present embodiment, notches 34 a are formed at four locations in one pitch located at the uppermost stream of the screw 34. Since the discontinuous fibers introduced into the casing 32 have a low bulk density, the discontinuous fibers pass through the notches 34a and efficiently move downstream. The amount of processing per unit time can be increased.

  As shown in FIG. 2, the casing 32 is formed with an exhaust port 32 a connected to a decompression pump P that decompresses the inside of the casing 32. A filter 35 is provided so as to cover the exhaust port 32a. The filter 35 can prevent the discontinuous fibers in the casing 32 from being discharged outside the casing 32. In the present embodiment, a filter 35 is disposed between the casing 32 and the screw 34. It is preferable to make the gap between the casing 32 and the screw 34 minute. In this case, if the filter 35 is made of metal, friction can be reduced. From this viewpoint, the filter 35 is preferably a sintered wire mesh. Further, when the filter 35 is a sintered wire mesh, the sintered wire mesh also serves as the casing 32.

  The decompression pump P is detachably connected to the pushing device 30. The decompression pump P is not particularly limited as long as the pressure inside the casing 32 can be reduced, but a vacuum pump is preferably used.

  Further, the casing 32 is formed with a discharge port 32b for discharging the discontinuous fibers having an increased bulk density to the first kneader 10. The discharge port 32 b is provided downstream of the screw 34.

  A drive unit 36 is connected to a shaft end of the rotating shaft 33 opposite to the screw 34 via a speed reducer 37 that distributes torque to the rotating shaft 33. The drive unit 36 and the speed reducer 37 rotate the rotation shaft 33 at a predetermined rotation speed.

<Continuous fiber supply unit>
As shown in FIG. 1, the continuous fiber supply part 40 supplies the continuous fiber introduce | transduced into the continuous fiber introduction part 12c of the cylinder 12 of the 1st kneader 10. The continuous fiber supply unit 40 includes a placement unit 42 for placing a fiber raw material 41 around which a bundle of a plurality of continuous fibers is wound. The mounting part 42 has first and second guide parts 42 a and 42 b for taking out the tip of the fiber bundle from the fiber raw material 41 and introducing it into the continuous fiber introducing part 12 c of the cylinder 12 of the first kneader 10. ing. When a plurality of fiber raw materials 41 wound with a bundle of fibers are arranged, each of the tips of the fiber bundles of the plurality of fiber raw materials is passed through the first guide portion 42a and assembled. . The 1st guide part 42a may be a guide plate provided with the plate-shaped member in which the hole part for letting a fiber pass was formed. Moreover, the mounting part 42 may further include a second guide part 42 b for guiding the continuous fibers that have passed through the first guide part 42 a to the continuous fiber introduction part 12 c of the first kneader 10. The second guide portion 42b is, for example, a roll-shaped member that protrudes from the upper end of the placing portion 42, and applies tension to the fiber bundle and prevents the fiber bundle from being unwound.

  Next, a method for manufacturing a composite material will be described using the kneading apparatus 1 of the present embodiment shown in FIGS. First, a method for increasing the bulk density of discontinuous fibers in the pushing device 30 shown in FIG. 2 will be described.

  First, discontinuous fibers are prepared. For example, recycled carbon fiber is prepared as the discontinuous fiber. As shown in FIG. 2, the discontinuous fibers are placed on the conveyance unit 31, and the discontinuous fibers are conveyed into the casing 32.

  The screw 34 is rotated by rotating the rotary shaft 33 at a predetermined rotational speed using the drive unit 36 and the speed reducer 37. Since the discontinuous fibers introduced into the casing 32 have pitches P1 to P5 of the screw 34 decreasing from the upstream side toward the downstream side, the first kneader 10 is removed by removing the air in the discontinuous fibers. It is possible to efficiently increase the bulk density of the discontinuous fibers toward the connection region (the discharge port 32b of the pushing device 30 and the discontinuous fiber introduction portion 12b in the first kneader).

  Further, the decompression pump P is connected to the exhaust port 32a of the casing 32, and the decompression pump P is activated. Thereby, since the inside of the casing 32 into which the discontinuous fibers are introduced can be decompressed, the bulk density of the discontinuous fibers can be efficiently increased by removing the air in the discontinuous fibers. Moreover, the discontinuous fibers introduced into the casing 32 can be prevented from leaking to the outside by the filter 35 covering the exhaust port 32a. Further, if the filter 35 is a sintered wire mesh disposed between the casing 32 and the screw 34, it can serve as a casing and reduce friction.

  In the present embodiment, as shown in FIG. 6, a notch 34 a is formed at the upstream end of the screw 34. For this reason, a part of the discontinuous fibers can move downstream through the notches 34a (in FIG. 2, a part of the discontinuous fibers is dropped downward), so that the promotion of the discontinuous fibers is promoted. Therefore, the efficiency which raises the bulk density of a discontinuous fiber can be improved.

  Thus, when the discontinuous fiber introduced into the pushing device 30 is propelled downstream by the screw 34 and reaches the discharge port 32b, the air in the discontinuous fiber escapes and the bulk density can be increased. . For this reason, a large amount of discontinuous fibers can be introduced into the first kneader 10 from the discontinuous fiber introduction portion 12 b in the first kneader 10. Therefore, in the first kneader 10, the production efficiency of the composite material by kneading the resin and the discontinuous fibers can be improved.

  Moreover, a continuous fiber is prepared. The continuous fiber is a plurality of continuous fiber raw materials 41, and the plurality of fibers is, for example, 12,000 or more, may be 24,000 or more, or may be 50,000 or more. In the present embodiment, the fiber raw material 41 is a bundle (roving) of 12,000 or more fibers, and a plurality of bundles of these fibers are prepared. The continuous fiber is, for example, glass fiber. Specifically, the fiber raw material 41 in which a plurality of continuous fibers are wound is placed on the placement part 42 of the continuous fiber supply unit 40, and the tip of the fiber raw material 41 is passed through the first guide part 42a. It is made to support by the 2nd guide part 42b.

  Moreover, as shown in FIG. 1, the resin raw material 50 introduced into the second kneader 20 is melted. Specifically, the resin raw material 50 is supplied from the screw feeder via the hopper 24 of the second kneader 20. The resin raw material 50 is, for example, in a pellet form. The resin raw material 50 may use a plurality of types of resins and may contain additives. The resin raw material 50 is a thermoplastic resin. The kneading shaft 21 is rotated at a predetermined rotational speed using the drive unit 23a and the speed reducer 23b, and the resin material 50 in the cylinder 22 is kneaded by the kneading shaft 21.

  Next, the resin kneaded by the second kneader 20, the discontinuous fibers supplied from the pushing device 30, and the continuous fibers supplied from the continuous fiber supply unit 40 are introduced into the first kneader 10. In this step, the molten resin discharged from the discharge port 22a of the second kneader 20 is introduced into the resin introduction portion 12a of the first kneader 10. In addition, the discontinuous fiber having a high bulk density discharged from the discharge port 32b of the pushing device 30 is introduced into the discontinuous fiber introducing portion 12b. In addition, the leading ends of a plurality of continuous fibers guided from the first guide unit 42 a and the second guide unit 42 b of the continuous fiber supply unit 40 are introduced into the continuous fiber introduction unit 12 c of the first kneader 10.

  Next, a composite material is manufactured by kneading discontinuous fibers, continuous fibers, and resin. This step is performed as follows, for example.

  The supply amount of continuous fibers and discontinuous fibers is determined by the rotational speed of the kneading shaft 11 of the first kneader 10 and the equivalent diameter of the screw 11a to be mounted. The screw 11a and the paddle 11b are arranged so that the inside of the first kneader 10 has an appropriate pressure distribution according to the target fiber length.

  By rotating the rotating shaft 11c using the drive unit 13a, the kneading shaft 11 is rotated at a predetermined rotation speed. Note that the rotation speed of the kneading shaft 11 of the first kneading machine 10 is slower than the rotation speed of the kneading shaft 21 of the second kneading machine 20. In this case, the resin can be kneaded well with the second kneader 20 and the fibers can be entangled with the resin with the first kneader 10.

  Since the discontinuous fiber is introduced from a position upstream of the continuous fiber, first, the molten resin supplied from the second kneader 20 and the discontinuous fiber supplied from the pushing device 30 are kneaded. Since the paddle 11b is disposed on the downstream side of the discontinuous fiber introducing portion 12b in the kneading shaft 11, the paddle 11b can increase the filling rate of the resin around the paddle 11b as shown in FIG. The discontinuous fibers can be dispersed in the resin and each of the discontinuous fibers can be impregnated with the resin. In this state, continuous fibers are introduced from the continuous fiber supply unit 40, and the resin, discontinuous fibers, and continuous fibers are kneaded. By introducing the discontinuous fiber from the position upstream of the continuous fiber, it is not necessary to lower the filling rate before the weir body 14 in order to disperse the discontinuous fiber in the resin. Can be increased.

  Further, since the paddle 11b has a higher kneading function than the screw 11a, the gap between the paddle 11b and the cylinder 12 can be sealed with a resin by increasing the filling rate. can do. For this reason, since it can prevent that air flows into the pushing device 30 from the 1st kneader 10 located in the downstream, the pressure reduction state in the pushing device 30 can be maintained efficiently. Therefore, since the bulk density of the discontinuous fibers can be efficiently increased in the pushing device 30, the processing amount per unit time can be increased.

  The continuous fibers are kneaded with the discontinuous fibers dispersed in the resin. By rotating the kneading shaft 11, the resin, the discontinuous fiber and the continuous fiber are kneaded while pressure is applied to the resin, the discontinuous fiber and the continuous fiber moving through the flow path formed between the kneading shaft 11 and the cylinder 12. To do.

  As the screw 11a rotates, the kneaded material that has moved through the flow path between the kneading shaft 11 and the cylinder 12 fills the space between the screw 11a and the weir body 14 located on the most downstream side, as shown in FIG. And since moderate back pressure is applied in the area | region where the screw 11a does not rotate, the unopened fiber which carried out the short pass of the continuous fiber can be separated. For this reason, the opened fiber can be impregnated with the resin. Moreover, since the fiber opened at the filling part is dispersed in the resin, the kneaded product can be homogenized. In addition, by adjusting the length of the arc of the opening 14a of the weir body 14 and the opening ratio, it is possible to suppress discharge of an excessively long unopened fiber bundle.

This kneaded material passes through the opening 14a of the weir body 14, and is discharged from the discharge port 15a of the die 15 under a low pressure (for example, 1 to 5 kgf / cm ² ). By performing the above steps, a composite material in which a resin and fibers are kneaded can be manufactured.

  The kneading apparatus 1 according to the present embodiment includes a weir body 14 having a plurality of arc-shaped openings 14 a along the rotation directions of the screws 11 a of the two kneading shafts 11. Since the opening 14a is long in the circumferential direction, pressure loss can be reduced and the propulsive force of the screw 11a can be efficiently transmitted. For this reason, it is possible to adjust the pressure distribution in the first kneading machine 10 and add an appropriate resistance to the kneaded material kneaded with the fiber and resin of the filling portion where the screw 11a does not rotate before the weir body 14, A bundle of a plurality of continuous fibers can be separated. For this reason, since it is easy to impregnate resin with each of the opened fiber, the impregnation rate can be improved. As described above, the screw 11a is not provided in the filling portion before the weir body 14 and the fiber opening is promoted by pressure. Therefore, the degree of freedom of the arrangement on the upstream side in the first kneader 10 is increased, and the rotational speed of the screw 11a is increased. The influence of is very small. For this reason, since fiber breakage can be prevented regardless of the rotation speed, a long fiber length can be maintained. Therefore, the fiber length of the fibers derived from continuous fibers contained in the composite material can be increased to, for example, about 10 mm to about 30 mm.

  According to the kneading apparatus 1 and the kneading method of the present embodiment, continuous fibers and discontinuous fibers are introduced into the kneading apparatus. For this reason, even if the fiber length of the fiber derived from the discontinuous fiber contained in the composite material is short, the fiber length of the fiber derived from the continuous fiber is long, so that characteristics such as impact resistance and strength can be supplemented. Therefore, even when discontinuous fibers are used, a composite material having high characteristics can be manufactured.

  For this reason, since a recycled fiber can be used as a discontinuous fiber, the kneading apparatus 1 and the kneading method of this Embodiment can reduce an environmental load.

  As described above, the kneading apparatus 1 and the kneading method of the present embodiment can produce a composite material having high characteristics even when discontinuous fibers are used. For this reason, the composite material manufactured by the kneading apparatus 1 and the kneading method of the present embodiment can be suitably used for automobile applications and the like.

  Here, in the present embodiment, a two-stage type provided with a second kneader 20 for kneading the resin and a first kneader 10 for kneading the resin and fibers kneaded by the second kneader 20. However, the kneading apparatus of the present invention is not limited to the two-stage type. For example, a one-stage kneading apparatus can be realized by introducing pellet-shaped resin raw material into the upstream side and introducing fibers into a region where the resin is melted in the cylinder.

  Moreover, in this Embodiment, in order to lengthen the fiber length of the fiber derived from the continuous fiber contained in a composite material, although it adjusts with the weir body 14 which has the opening part 14a, it is not specifically limited, Other It may be adjusted by means. For this reason, in the kneading apparatus of the present invention, the weir body 14 may be omitted.

  Moreover, although the kneading apparatus 1 of this Embodiment is provided with the pushing apparatus 30 in order to raise the bulk density of the discontinuous fiber supplied to the 1st kneading machine 10, the pushing apparatus 30 may be abbreviate | omitted.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

DESCRIPTION OF SYMBOLS 1 Kneading apparatus, 10 1st kneading machine, 11, 21 Kneading shaft, 11a1 mountain, 11a2 valley, 11a, 21a, 34 Screw, 11b paddle, 11c, 21b, 33 Rotating shaft, 12, 22 cylinder, 12a Resin introduction part, 12b discontinuous fiber introduction part, 12c continuous fiber introduction part, 12d inner peripheral surface, 13a, 23a, 36 drive part, 13b, 23b, 37 speed reducer, 14 weir body, 14a opening part, 14a1 outer contour line, 14a2 inner contour line 14a3 side contour line, 14b through hole, 15 die, 15a, 22a, 32b discharge port, 20 second kneader, 24 hopper, 30 pushing device, 31 transport unit, 32 casing, 32a exhaust port, 35 filter, 40 continuous fiber supply unit, 41 fiber raw material, 42 placement unit, 42a first guide unit, 42a second guide unit, 50 resin raw material, P decompression port Flop, P1~P5 pitch.

Claims (6)

Introducing continuous fibers into the kneading device;
Introducing discontinuous fibers into the kneading device;
Introducing the resin into the kneading apparatus;
A kneading method comprising a step of kneading the continuous fiber, the discontinuous fiber, and the resin. The continuous fiber is glass fiber,
The kneading method according to claim 1, wherein the discontinuous fibers are carbon fibers.   The kneading method according to claim 1 or 2, wherein the discontinuous fibers are introduced from a position upstream of the continuous fibers.   The kneading method according to claim 1, wherein the discontinuous fibers are recycled fibers. A first introduction part for introducing continuous fibers;
A second introduction part for introducing discontinuous fibers;
A kneading apparatus comprising a kneading shaft for kneading the continuous fibers, the discontinuous fibers, and the resin. The kneading apparatus according to claim 5, wherein the second introduction part is located upstream of the first introduction part.

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