WO2018088471A1

WO2018088471A1 - Carbon fiber reinforced plastics extruded material and method for manufacturing same

Info

Publication number: WO2018088471A1
Application number: PCT/JP2017/040424
Authority: WO
Inventors: 歳博伊原; 福田　徳生; 幸典山本
Original assignee: 株式会社イハラ合成; 愛知県
Priority date: 2016-11-11
Filing date: 2017-11-09
Publication date: 2018-05-17
Also published as: JP6421300B2; JPWO2018088471A1

Abstract

The present invention makes it possible to manufacture short carbon fiber reinforced extruded material at low cost and use a recycled product. A wire rod according to the present embodiment is a wire rod of CFRTP representing carbon fiber reinforced plastics with long axes of carbon fibers oriented in a long axis direction of the wire rod, wherein 10 to 50 W/W% of short carbon fibers are contained, and an orientation angle thereof is 0 to 7° and preferably 0 to 4° with respect to the long axis direction of the wire rod. The wire rod is extruded from a melting extrusion machine and caused to pass through a cooling water bath, and a wire rod F not completely solidified is wound by a manual wire winding machine with an extending degree thereof adjusted to be obtained. When extruded, melted resin has a Reynolds number Re of 10^-6 to 10 and more preferably 10^-5 to 1. The wire rod is laid on a pressing machine and formed in sheet material by thermal pressing.

Description

Carbon fiber reinforced resin extruded material and method for producing the same

The present invention relates to an extruded material made of short (discontinuous) carbon fiber reinforced resin and a manufacturing method thereof.

Carbon fiber reinforced resin (CFRP, CFRTP) is a composite material in which carbon fiber is impregnated with a resin to improve the strength, and is used as a light weight and high strength material as a composite material with a material having a high elastic modulus. However, because carbon fiber has high strength but low toughness, it is difficult to mold carbon fiber reinforced resin. To improve this, various carbon fiber lengths have been cut to 0.05 mm to 3 mm. A short carbon fiber reinforced resin is also provided. However, industrial waste treatment such as incineration and embedding is still in use, because there is a low yield in the molding process, or there is no recycling method for molded products, and an effective recycling method is desired. ing.

In Patent Document 1, a fiber reinforced plastic containing a discontinuous carbon fiber (A) and a thermoplastic resin (B), and the diameter of a cross section perpendicular to the fiber axis of a single fiber of the discontinuous carbon fiber (A) is 9 to There has been proposed a fiber reinforced plastic having a discontinuous carbon fiber (A) of 13% by mass and 35% by mass or more contained in the fiber reinforced plastic.

In Patent Document 2, in the production of a web (nonwoven fabric deposit) and a stampable sheet, carbon fibers and a thermoplastic resin having an average diameter of 7 μm and an average length of 13 μm are put into a dispersion and dispersed by stirring. Then, when the obtained web was poured into a papermaking machine and observed with a microscope, a web in which reinforcing fibers and thermoplastic resin were dispersed was obtained, and a method for processing this into a stampable sheet has been proposed (Example 1). .

Patent Document 3 describes a method of obtaining a carbon fiber mat by a papermaking method in which a chopped carbon fiber is introduced into a dispersion, stirred, and then poured into a large square sheet machine in the production of a stampable sheet. Example 1).

Patent Document 4 discloses a method for producing a prepreg capable of continuously producing a prepreg having good linearity or a prepreg having excellent bending characteristics and capable of sufficiently orienting discontinuous fibers in a thermoplastic resin, and an extrusion treatment. The manufacturing system of a tool and a prepreg is provided, and patent document 5 is the molded object using the prepreg of patent document 4, and its manufacturing method.

Patent Document 6 proposes a resin sheet in which carbon fibers having an average fiber length of 0.1 to 10 mm are oriented at a ratio of 65 to 95% in one direction, and the resin sheet is melted in a die. The carbon fiber composite resin material is poured, and the discharged resin material is made to flow between two heated nip rolls.

Non-Patent Document 1 introduces a method for producing a thermoplastic stampable sheet by using a carbon fiber thread as a woven fabric and laminating a thermoplastic resin film.

In Non-Patent Document 2, after a commercially available carbon fiber fabric is treated with a desizing agent, the carbon fiber is used by using a film molding extruder (manufactured by Plastic Engineering Laboratory Co., Ltd.) installed at the Ishikawa Next Generation Industry Creation Support Center. A stampable sheet continuous production method in which a thermoplastic resin (polyamide 6) is impregnated on a woven fabric has been proposed.

Non-Patent Document 3 discloses a method for producing a short carbon fiber orientation sheet in which a short carbon fiber orientation mat is produced from a suspension of short carbon fibers using a hydrodynamic process and impregnated with a matrix resin. It is disclosed.

JP 2013-203772 Japanese Patent No. 4920909 Japanese Patent Laid-Open No. 2014-51023 Japanese Unexamined Patent Publication No. 2016-98271 JP 2016-141074 JP 2013-221114 A

However, the extruded material of Patent Document 1 is a carbon fiber reinforced thermoplastic resin (plastic) having light weight and strength and having fluidity suitable for injection molding. There is an intention to orient the discontinuous carbon fibers in all directions, and it does not assume a unidirectional carbon fiber oriented wire. Further, in all the examples, the fiber length is 6 mm, and so-called long fiber, chopped fiber length CF is used, so it is difficult to realize a wire containing short carbon fiber having a fiber length of 3 mm or less. is there.

Patent Documents

2 and 3 and

Non-Patent Documents

1 and 2 relate to a method of manufacturing a stampable sheet which is a carbon fiber reinforced sheet, and both are sheets in which the direction of the fibers is dispersed in all directions or crosses within the sheet surface. A thermoplastic sheet having short carbon fibers oriented in one direction on the inner surface of the sheet is difficult to realize.

Patent Documents

4 and 5 are prepregs and molded articles thereof, but there is a problem that a sufficient orientation rate cannot be obtained by the manufacturing methods described in

Patent Documents

4 and 5. Patent Document 6 is a method in which a thick resin discharged from a thick die is sandwiched between nip rolls to form a sheet, and there is a problem that even this method cannot obtain a sufficient orientation rate. Also, recycled products are not used.

Non-Patent Document 3 reports that as a method of reusing expensive carbon fiber reinforced resin, after removing the matrix resin, the recovered carbon fiber is cut and the discontinuous fiber is classified by the fiber length, or a new short fiber Hydrodynamic Process method in which short carbon fibers are suspended in water, and the suspension is pressurized and discharged from the discharge nozzle along the inner wall surface of the rotating drum, whereby the short carbon fibers are oriented and laminated in the rotational direction. And the sheet | seat which further solidified the short carbon fiber orientation mat | matte obtained by this method with matrix resin is disclosed.

However, when using recycled carbon fiber reinforced resin members, once the carbon fiber is separated and recovered from the resin, if the recovered fiber is long fiber, the fiber is cut and the fiber length is classified, or the short carbon fiber reinforced Even in the case of a resin member, there is a problem that a pretreatment process for separating and collecting fibers from the resin is required.

In addition, the short carbon fiber suspension concentration used in the fluid molding method is less than 10 w / w% and is usually about 5 w / w%. With suspensions of 10 w / w% or more, high pressure is applied to nozzle injection. In addition to this, there is a problem that stable laminar flow injection from the nozzle becomes difficult.

Moreover, it requires a flow molding process that is used only to orient the short carbon fibers and a fiber reinforced resin molding process that impregnates and fixes the resin to the resulting short carbon fiber orientation mat. There is an essential problem that the number of steps is increased as compared with the extrusion orientation method.

An object of the present invention is to efficiently provide a carbon fiber reinforced thermoplastic resin extruded material of short fibers or discontinuous fibers that secure unidirectional orientation at low cost, and to utilize a recycled product of carbon fiber reinforced resin. Is to realize.

In view of the above problems, the first invention of the present invention includes 10 to 50 w / w% carbon fiber, 50 to 90 w / w% resin, which is a short fiber for reinforcement having an average fiber length of 0.05 to 3 mm, The carbon fiber reinforced resin extruded material has an orientation angle of 0 to 7 ° with respect to the extrusion direction.

The extruded material made of carbon fiber reinforced resin includes wire materials such as monofilaments and multifilaments, films, sheet materials, rod materials, plate materials and the like. In general carbon fiber reinforced resin, in order to ensure strength, the product is a bulk or sheet material in which carbon fibers are randomly oriented. In the carbon fiber reinforced resin extruded material of the present invention, in the case of a wire material, the carbon fiber is a wire material. Basically, it is different in that it is within a specific small orientation angle range with respect to the major axis direction and with respect to one direction in the plane in the case of a sheet material.

When the average fiber length of the carbon fiber is less than 0.05 mm, the tensile strength and impact strength of the extruded material made of carbon fiber reinforced resin are lowered, and when the average fiber length exceeds 3 mm, the melt viscosity is increased and the moldability is lowered. Not only that, the fiber breaks during the melt extrusion process, and the fiber length varies, so the quality of the extruded material decreases. Even if the fiber breakage in the melt extrusion process is suppressed, the long fiber reinforced resin is extruded, so that there is a problem that the moldability is low and the mechanical damage of the apparatus is large. The diameter of the carbon fiber can be appropriately selected, but is preferably 5 μm to 18 μm. For example, the thickness of one carbon fiber may be 5 to 7 μm for a PAN system and 10 to 15 μm for a pitch system.

Extruded materials with carbon fibers below 10 w / w% are not strong enough. On the other hand, if the carbon fiber content exceeds 50 w / w%, molding is difficult due to damage to the screw of the melt extruder and increased extrusion pressure. The toughness of the extruded material thus obtained is likely to be broken and may become a hindrance during secondary processing. When the orientation angle of the carbon fiber with respect to the extrusion direction exceeds 7 °, it causes unevenness in the size of the extruded material and molding distortion due to disproportionation of the internal stress of the extruded material due to variation in orientation.

The resin is polyamide (PA) resin, acrylonitrile-butadiene-styrene copolymer (ABS) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS) resin, polypropylene (PP) resin, polyetherimide (PEI). ) Resin, polyethylene terephthalate (PET) resin, polyether ether ketone (PEEK) resin, and polyether ketone ketone (PEKK) resin. The fiber reinforced resin may be new or recycled. The recycled product as used herein refers to recovered products, unused mill ends, crushed materials thereof, and recycled products. Moreover, what pelletized these is called a reproduction | regeneration pellet. Examples of the material include CFRTP, such as PA66CF20 and PA66CF30.

The polyamide-based resin is preferably at least one selected from nylon 6, nylon 66, nylon 610, and nylon 612.

The orientation of the carbon fiber is exemplified by cutting the fiber reinforced resin extruded material, observing the cut surface using a microscope, and calculating by calculation processing.

The carbon fiber may be PAN-based (polyacrylonitrile fiber is a raw material) or pitch-based (coal tar or other petroleum-based carbon fiber), or a composite fiber of carbon fiber and other fibers. You may contain the functional agent for improving the softness | flexibility of an extrusion material.

When the extruded material is a wire material such as a monofilament, a wire material whose cross section perpendicular to the wire material axis direction is round, polygonal, rectangular, elliptical or the like is included.

The present invention includes a sheet-shaped or long-shaped short carbon fiber-oriented molded body obtained by bundling and crimping a plurality of wires that are extruded materials.

The sheet material including the wire material that is an extruded material is pressed at a temperature at which the resin constituting the wire material is fused after a plurality of wire materials in which the reinforcing short carbon fibers according to the present invention are oriented in the long axis direction are bundled in one direction. A short carbon fiber in-plane unidirectional sheet is included.

The sheet material including the wire material that is an extruded material is a resin constituting the wire material after the wire material in which the reinforced short carbon fibers according to the present invention are oriented in the major axis direction is used as a woven or knitted fabric for warp, weft, and diagonal yarns. The sheet | seat etc. which press-contact at the temperature which melt | fuses are included.

As shown in FIG. 2, the sheet material including the wire material that is an extruded material includes an example in which wire materials oriented in the extrusion direction are laminated at a combination angle of 0/90 °. The combination angle of the wire rods to be laminated can be an angle corresponding to the strength direction required for the final product. Also, isotropic fiber alignment materials can be produced by combining wire rods in all directions.

In FIG. 2, it is possible to form a sheet or a bar by increasing the number of layers to a sheet material by decreasing the number of layers.

When the extruded material is a sheet material, carbon fiber reinforcement with short fiber orientation obtained by melt extrusion molding of regenerated pellets containing 10-50 w / w% short carbon fiber while maintaining the short carbon fiber content and fiber length almost It is also possible to use a plate material obtained by laminating resin sheet materials (Carbon Fiber Alignment Material Stampable Sheet) or a laminated molded product (Sheet Molding Material).

In the present invention, a matrix resin may be impregnated from the outside as necessary for the purpose of fusing a wire in which reinforced short carbon fibers are oriented in the major axis direction. The matrix resin used in that case is basically the same as the thermoplastic resin constituting the wire, but a substance such as ABS rubber or high-density polyethylene may be added to improve strength and flexibility. .

The wire material in which the reinforced short carbon fibers according to the present invention are oriented in the major axis direction can be impregnated with a thermosetting matrix resin to form a fiber reinforced plastic. In this case, the thermosetting resin is an epoxy resin, a silicon resin, or the like, and a compatibilizing agent of a thermoplastic resin and a thermosetting resin can also be used.

According to a second aspect of the present invention, a fiber reinforced resin pellet or a carbon fiber reinforced resin crushed material containing 10 to 50 w / w% carbon fiber, which is a short fiber for reinforcing, is randomly extruded. The extruded short fiber for reinforcement containing 10 to 50 w / w% of carbon fiber with an average fiber length of 0.05 to 3 mm is extruded by melting and extruding the extruded material at a screw rotation speed of 10 to 100 rpm. A melt extrusion process for extruding the extruded material oriented in the direction, and a cooling and solidifying process for cooling and solidifying the melt-extruded extruded material, and the cooled and solidified extruded material is a wire or a sheet material, and has an average fiber length 10 to 50 w / w% carbon fiber which is a reinforcing short fiber having a thickness of 0.05 to 3 mm, 50 to 90 w / w% resin, and the orientation angle of the carbon fiber with respect to the extrusion direction is 0 to 7 °. Characterized by carbon A method for producing a fiber-reinforced resin extruded material.

In the melt extrusion step, in order to suppress breakage of the reinforcing fibers, it is preferable that the melt resin is melt extruded in a range of Reynolds number Re of 10 ⁻⁶ to 10, more preferably 10 ⁻⁵ to 1.

In order for the carbon fibers to be oriented in the resin matrix, it is important that the molten resin passes through the discharge nozzle in a laminar flow. The Reynolds number Re is known as an index representing the flow of molten resin in the discharge nozzle. It is known that if the Reynolds number Re is less than a certain value, it becomes laminar flow, and if this exceeds a certain value, it becomes turbulent flow. The Reynolds number when laminar flow transitions to turbulent flow is called the critical Reynolds number. As an example, it is known that the flow in a circular pipe is 2,300 to 4,000. It is said that if the Reynolds number Re is equal to or less than the limit Reynolds number, the flow becomes laminar, and if the Reynolds number Re is higher than that, the flow becomes turbulent. The Reynolds number Re is expressed by the following equation.
(Equation 1)
Re = (V * a * ρ) / μ

Here, * is a symbol indicating multiplication, V (m / s) is the average speed of the molten resin, a (m) is the tube inner diameter of the discharge nozzle, ρ (kg / m ³ ) is the density of the molten resin, μ (kg / (M · s)) is expressed by the viscosity coefficient of the molten resin.

The cooled and solidified extruded material is preferably a wire material or a sheet material, and is preferably provided with a sheet material forming step in which the wire material or sheet material is spread on a press and formed into a sheet material by hot pressing.

For example, after laminating the wires as shown in FIG. 2, the short carbon fibers are oriented in a specific direction by immersing the same resin as the wire component, for example, as a matrix material so as to fill the gaps of the wire bundle, and further hot pressing. A production method for producing a fiber reinforced prepreg (sheet-like intermediate material) is possible.

The fiber-reinforced prepreg can be used as a molding material for stampable sheets and composites for press working.

The resin includes the polyamide (PA) resin, the acrylonitrile / butadiene / styrene copolymer (ABS) resin, the polycarbonate (PC) resin, the polyphenylene as well as the extruded material made of carbon fiber reinforced resin. Sulfide (PPS) resin, polypropylene (PP) resin, polyetherimide (PEI) resin, polyethylene terephthalate (PET) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin Examples of such a thermoplastic resin include carbon fiber reinforced resin filled with carbon fiber and reinforced.

The short carbon fiber reinforced resin is melt-extruded without separating the reinforced short carbon fiber and the matrix resin from the carbon fiber reinforced thermoplastic resin containing 10 w / w% to 50 w / w% of short carbon fiber relative to the resin. Thus, the short carbon fibers are contained in an amount of 10 w / w to 50 w / w% with respect to 50 w / w to 90 w / w% of the resin, and the short fibers are characterized by being oriented in the extrusion direction by the fibers.

When the cooled and solidified extruded material is a sheet material, a slit-type carbon fiber reinforced thermoplastic resin melt solution containing 10 w / w% to 50 w / w% of short carbon fibers is kept in a laminar flow state with respect to the resin. The short carbon fiber is extruded from the discharge port and oriented in one direction in the plane.

A laminate in which the carbon fiber reinforced sheet material with short carbon fiber orientation formed by this method is directly or cut into an appropriate size and laminated so that the fiber orientation of each sheet is appropriately random. Can be manufactured. This laminate can be used as a material along the mold surface of a structure having a curved surface or a bent surface. The fiber orientation of each sheet is different, and the fiber as a whole of the laminate has high strength in all major directions because the fibers are oriented in all major directions. In addition, when the final product needs strength in a specific direction, the orientation of each sheet can be appropriately adjusted and laminated.

In the method for producing the extruded material made of carbon fiber reinforced resin, the pellets may be polyamide (PA) resin, acrylonitrile / butadiene / styrene copolymer (ABS) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS). Carbon fiber, polypropylene resin (PP) resin, polyetherimide (PEI) resin, polyethylene terephthalate (PET) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin Manufactured by crushing the filled and reinforced carbon fiber reinforced resin, putting it into a melt extruder having a semiflight type or full flight type screw at a melting temperature of 200 to 320 ° C, extruding the extruded material, and cutting the extruded material It is preferable to have a pellet forming step

In this pellet forming step, waste products of carbon fiber reinforced resin products are crushed, regenerated pellets are obtained by melt extrusion, and the regenerated pellets are melt extruded to orient the short fibers in the extrusion direction. Examples of waste products include resin parts such as OA parts, automobile parts, and electric parts.

The present invention also includes a method in which waste crushed material is sufficiently kneaded in a molten state and directly melt extruded without producing recycled pellets. This method is also preferable because the short fibers are oriented in the extrusion direction.

The present invention is a composite base material in which short carbon fibers are oriented in the fiber major axis direction, and can be used as a raw material for molding into woven fabrics, knitted fabrics, sheet materials, plate materials, bar materials and the like.

According to the present invention, it is possible to efficiently provide an extruded material made of carbon fiber reinforced resin in which reinforced carbon fibers are oriented in the extrusion direction and high in strength in a specific direction at low cost. In addition, by stacking or combining the extruded materials in which the fibers are oriented at an angle, it is possible to obtain a final product that is isotropically high in the required direction or in all major directions. Further, by reusing the waste product made of carbon fiber reinforced resin, the extruded material can be provided at a lower cost.

It is the conceptual diagram and photograph of the short-carbon fiber unidirectionally oriented resin reinforced wire F of this invention embodiment. It is explanatory drawing of the prepreg (sheet-like intermediate material) using the wire of embodiment of this invention. (A)-(d) is sectional drawing which shows the cross-sectional shape of the nozzle | cap | die of a melt extruder. It is an imaging figure of the X-ray diffraction pattern of the wire F of embodiment of this invention. It is the fiber length distribution map of the carbon fiber in a pellet similarly. It is the fiber length distribution map of the carbon fiber in the wire F similarly.

DETAILED DESCRIPTION OF THE INVENTION A wire F obtained by orienting carbon fibers according to an embodiment of the present invention in the longitudinal direction of the wire, a manufacturing method thereof, a sheet material using the wire F and the like will be described with reference to the drawings.

The wire F of the present embodiment is a wire that is an example of an extruded material of CFRTP that is a carbon fiber-reinforced thermoplastic resin, and 20% by weight of carbon fiber C having an average fiber length of 0.05 to 3 mm and a diameter of 5 to 18 μm, The resin P is contained at 80% by weight, and the orientation angle of the carbon fiber C with respect to the long axis direction X of the wire is 0 to 7 °, preferably 0 to 4 °. As shown in FIG. 1, the carbon fiber C is characterized by being oriented in one direction in the wire major axis direction X.

Carbon fiber reinforced resin may be new or recycled. In addition, the cross-sectional shape of the wire F of the present embodiment includes not only a substantially circular shape, but also an elliptical shape, a triangular shape, a quadrangular shape such as a quadrangular shape, a pentagonal shape, a rectangular shape, and other irregular shapes. However, when the diameter of the wire F is too thin, when used as a hair material for industrial brushes, the hair and hips are too weak and the polishing and strength are lowered. In addition, the uniformity is reduced. Therefore, the diameter of the wire F is preferably 0.2 to 1.5 mm, particularly preferably 0.4 to 1.0 mm.

When the wire material F is used as a processing wire material such as a sheet material or a rod material, it can be formed into a strand (string) having a thickness suitable for the application, for example, 1.5 to 10.0 mm.

It is also possible to use a prepreg (sheet-like intermediate material) that is obtained by bundling the wire F and laminating or weaving and knitting it into a sheet shape, or by dipping a matrix resin and hot-pressing it.

Also, for example, as shown in FIG. 2, the wire F oriented in the extrusion direction is laminated at a combination angle of 0/90 °, spread on a press, and hot pressed to form a sheet-like or plate-like prepreg. Is also possible. The combination angle of the laminated wires is not limited to 0/90 °, and can be set to an angle according to the strength direction required for the final product. In addition, isotropic fiber alignment materials can be produced by combining wire rods in all major directions.

The manufacturing method of the wire F according to the present embodiment melts carbon fiber reinforced resin (CFRP, for example, PA66CF20, etc.) pellets containing 10-50 w / w% of carbon fibers, which are reinforcing short fibers, in which the carbon fibers are randomly oriented. It was put into an extruder and melted at a temperature of 200 to 320 ° C. p. By melting and extruding the wire at m, a reinforcing material short fiber for reinforcing containing 10 to 50 w / w% of carbon fiber having an average fiber length of 0.05 to 3 mm and a diameter of 5 to 18 μm is oriented in the longitudinal direction of the wire. A melt extrusion step of extruding, and a step of cooling and solidifying the melt-extruded wire. The extruded molten mixture is cooled and solidified in a cooling bath, and then wound by a winder. Although it can be molded and used as it is from the state as it is, it may be subjected to stretching treatment, heat stretching treatment, and heat treatment as necessary. It is not limited to melting at a temperature of 200 to 320 ° C. This is because the melting temperature of the resin varies depending on the type of resin. In some cases, the upper limit temperature may be 60 ° C. above the melting point of the resin. Further, if the temperature is too high, the resin is thermally deteriorated, which is not preferable.

In the melt extrusion process, the speed V of the molten resin is at most within a range of 0.1 to 10 m / s. The viscosity coefficient of the molten resin, for example, nylon is within the range of 50 to 1000 kg / (m · s), for example, at 250 to 300 ° C., even if the nylon grade and shear rate are changed. Therefore, the resin flowing inside the discharge nozzle having a tube inner diameter of 0.25 × 10 ⁻³ to 5 × 10 ⁻³ m has a Reynolds number Re value of 2.7 × 10 ⁻⁵ to 1 in Equation 1 above. a .1 × 10 ^0. Therefore, the range will be further described.

In order to reduce the Reynolds number Re, there are options of lowering the discharge speed of the molten resin from the discharge nozzle or lowering the temperature of the molten resin in order to increase the viscosity. Even if the conditions are met, not only the productivity of the extruded material is reduced, but also the molten state of the resin becomes non-uniform, so the discharge from the discharge nozzle of the extruded material becomes unstable, leading to inhomogeneous quality. become.

On the other hand, when melt extrusion is performed with a large Reynolds number Re, there are options to melt extrusion at a high pressure to increase the discharge rate of the molten resin, or to lower the viscosity by increasing the melting temperature. However, it is not preferable because it causes breakage of reinforcing fibers, pressure-resistant reinforcement of equipment, wear damage, thermal deterioration of resin, and the like.

Therefore, in consideration of such circumstances, the velocity V of the molten resin is at most within a range of 0.1 to 1 m / s, and the viscosity coefficient also changes, for example, at 250 to 300 ° C., in the case of nylon, the grade and the shear rate. Even within the range of 50 to 2000 kg / (m · s). For this reason, in a molten resin flowing inside a discharge nozzle having a tube inner diameter of 0.25 × 10 ⁻³ to 5 × 10 ⁻³ m, the value of Re in the above equation 1 is 10 ⁻⁶ to 10, more preferably , In the range of 10 ^-5 to 1.

As shown in FIGS. 3A to 3D, the shape of the discharge port section of the discharge nozzle of the melt extrusion molding machine can be implemented in various modes depending on the application. For example, in the discharge nozzle 1 of (a), a circular monofilament is extruded through the circular hole 1a, and in the discharge nozzle 2 of (b), two monofilaments having a circular cross section are extruded through the two circular holes 2a. In the discharge nozzle 3 of c), a plurality of resins extruded through the plurality of linear holes 3a are combined, and as a result, a thin sheet material having a square cross section is extruded. In the discharge nozzle 4 of (d), the resin that has entered from the circular hole 4a of the nozzle is extruded from a slit-type discharge port 4b (for example, 1 mm thick, 10 mm wide) on the discharge side of the nozzle through an inclined surface, thereby forming a sheet material. Is pushed out.

When using regenerated pellets, a carbon fiber reinforced resin waste product is crushed and melt-extruded to form a recycle pellet, and the recycle pellet is fed into the melt extruder in the melt extrusion step.

In the pellet molding step, the resin P is cut and crushed from waste products such as OA resin parts made of carbon fiber reinforced resin CFRP, which is a kind of polyamide resin, and melted with a semiflight type or full flight type screw. Extrusion by an extruder is performed to obtain recycled pellets. When the regenerated pellet and the new pellet were cut and the cut surface was observed with a micrograph, there was no significant difference in the fiber length of the carbon fiber C, and there was almost no breakage of the carbon fiber during the melt extrusion process.

It is also possible to use recycled pellets without using recycled pellets, that is, throw the waste crushing material into the melt extruder as it is without going through the pellet forming step. In this case, it is necessary to sufficiently knead in the melt extrusion step. If melt extrusion is performed without going through the pellet forming step, the forming step can be simplified, which is preferable.

In the case of the wire F extruded using recycled pellets and the wire F obtained by extruding the waste crushing material as it is without being pelletized, the long axis of the carbon fiber C is in the process of discharging from the discharge nozzle. It was confirmed that not only on the surface but also inside, it was strongly oriented in the wire major axis direction X and the orientation angle was 0 to 7 °.

Examples of the polyamide-based resin include nylon 6, nylon 66, nylon 610, nylon 612, nylon 12, and nylon 6/66 copolymer, which are appropriately selected.

The wire F of the present embodiment has a high tensile strength, and by bundling a plurality of wires, it can be expected to improve the strength of the tensile force substantially proportional to the number of the wires, so that it is highly useful as a base material for a composite molded material for structural members. .

Hereinafter, the configuration and effects of the wire rod F of the present invention will be described in more detail with reference to examples and comparative examples. It should be noted that the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Evaluation of the characteristics of the wire F in the above and following examples was performed by the following method.

[Measurement of average fiber length of carbon fiber in pellets and wire]
About 5 g was cut out using pellets or wire as a sample, and heated to 500 ° C., which is a temperature at which no oxidization is reduced while purging with air, thereby thermally decomposing the matrix resin and fractionating the carbon fibers. Each sample was selected at random by a digital microscope, the length was measured to the 1 μm unit, a fiber length distribution curve was created, and the average fiber length was determined.

[Measurement of average degree of orientation of carbon fibers in wire]
Method A) For raw material pellets and wire rods obtained using them, observe the raw material pellet fracture surface, wire F surface, wire F fracture surface with Hilox Digital Microscope Model HI-SCOPE Advanced KH-3000, It was confirmed that the orientation of the carbon fibers in the wire F was one direction and the angle was 0 to 7 °. It was also confirmed that the reinforcing carbon fibers in the raw material pellets were randomly oriented.
B Method) By analyzing the X-ray diffraction image of the wire F, the approximate orientation of the reinforced short carbon fiber was confirmed.

[Tensile strength test of crushed material and recycled pellets]
JISK7162: 1994
Test piece: JISK71621B type Test speed: 5 mm / min
Room temperature: 23 ° C

[Charpy impact test of crushed material and recycled pellets]
JISK7111-1: 2012
Test piece: JISK7111-1 / 1eA
Distance between supports: 62 mm
Nominal pendulum energy (capacity): 100J
Room temperature: 23 ° C

[Tensile strength of wire]
Using a universal tensile tester manufactured by Shimadzu Corporation (model: AG-20kNXDplus), the tensile load of the wire was measured at a test speed of 10 mm / min, a distance between chucks: 70 mm, and room temperature: 23 ° C. The tensile strength of the wire sample per cross-sectional area estimated from the above was calculated.

[Bending test of sheet material]
JIS K 7171: 2008
Test piece: Cut into a width of 25 mm from a sheet of length 80 mm × width 100 mm × thickness 3 mm to obtain a test piece. The test piece was measured for bending strength and bending elastic modulus using a universal testing machine equipped with a three-point bending jig under the conditions of a distance between fulcrums of 48 mm and a crosshead speed of 2 mm / min.

Example 1 is an example of forming a wire using recycled pellets. One type of CFRTP, short fiber CF reinforced 66 nylon PA66CF20 (Nylon 66 mixed with 20% by weight of carbon fiber) made of short fibers containing random fibers in different directions. Separately collected without mixing, crushed and used as the first crushed material. The test piece produced by injection molding this first crushed material has a tensile strength of 162 MPa (sample number 3), a Charpy impact test result of 6.5 KJ / m ² (sample number 5), and an average carbon of carbon fiber C. The fiber length is about 300 μm. The first crushed material was cut, and the crushed second crushed material was put into a PSV 75 mm vented extruder (L / D = 32) equipped with a full flight type screw of Plaenji Co., Ltd. The resin was melt-extruded from the spinning discharge nozzle at a melting temperature of 270 ° C. and a screw rotation speed of 160 rpm to obtain a strand. The obtained strand is cooled and solidified, cut and formed into a recycled pellet. Here, the second crushed material is dried with a hot air dryer at 120 ° C. for 6 to 8 hours to lower the moisture content, and then charged into the extruder. As a result, the moisture content of the recycled pellets is, for example, 0.2%, preferably 0.1% or less. The tensile strength of the test piece produced by injection molding the recycled pellets is 170 MPa (sample number 3), and the Charpy impact test result is 6.1 KJ / m ² (sample number 5). It was the same. Further, it was confirmed that the carbon fiber C was not severely broken and maintained a substantially uniform length. This is considered to be because melt extrusion with less voiding and less voiding was possible.

The regenerated pellets were put into a desktop kneader MC15 (made by Netherlands Xplore Instruments BV) equipped with a biaxial conical screw (L / D = 7.8 to 19.1, screw inner diameter 12 to 9 mmΦ, screw length 172 cm) in the same direction, The temperature near the inlet was set at 290 ° C, the temperature at the middle of the barrel was set at 300 ° C, the temperature at the bottom of the barrel was set at 310 ° C, the screw rotation speed was set at 20 rpm, the recycled pellets were completely melted, and the discharge nozzle hole diameter was 0.75 mm. It discharges from one discharge nozzle. Then, it was naturally dropped, and the wire was wound up (winding speed: 12 m / min) to produce a wire F having an average diameter of 0.5 ± 0.1 mmφ. About the obtained wire F, the orientation state of the short carbon fiber was investigated with a digital microscope. In the wire F, it was confirmed that the carbon fibers C were oriented at an orientation angle of 0 to 7 ° with respect to the major axis direction of the wire.

Example 2 is an example of forming a wire using virgin CFRTP pellets. CFRTP pellets (Toray Industries, Inc.) were added to a desktop kneader MC15 (Xplore Instruments BV, the Netherlands) equipped with a biaxial conical screw in the same direction (L / D = 7.8 to 19.1, screw inner diameter 12 to 9 mmΦ, screw length 172 cm). Made of short fiber CF reinforced 66 nylon grade name: 3101T-20V), the temperature near the inlet is set at 290 ° C, the temperature in the middle of the barrel is set at 300 ° C, the temperature at the bottom of the barrel is set at 310 ° C, and the screw speed is 20r .pm, the CFRTP pellet is completely melted and discharged from one discharge nozzle having a discharge nozzle hole diameter of 0.75 mm. Thereafter, it was allowed to fall naturally, and the wire F was wound up (winding speed 12 m / min) to produce a wire having an average diameter of 0.5 ± 0.1 mmφ.

The viscosity coefficient μ of nylon of the molten resin is about 80 Pa · s (= 80 kg / (m · s)) at 290 ° C. The melt density ρ of nylon in CFRP is 1.3 × 10 ³ kg / m ³ . Further, when the average velocity V of the molten resin is calculated from the length of the wire coming out from the discharge nozzle, a wire having a length of 22 m per minute is obtained, and is 0.37 m / s. In addition, since the discharge nozzle hole diameter of the kneader used in this example is 0.375 × 10 ⁻³ m, the Reynolds number Re of the molten resin in Example 2 is calculated from these values to be 2 × 10. ^-3 , which is found to be within the range of 10 ⁻⁶ to 10 under laminar flow conditions (Re <2300).

For the raw material pellets (short fiber CF reinforced 66 nylon) and the obtained wire F, the orientation state of the short carbon fibers was examined with a digital microscope. In the fracture surface of the raw material pellets, the carbon fibers C were oriented in the random direction, whereas in the wire F, it was confirmed that the carbon fibers C were oriented in the longitudinal direction of the wires.

Using the RA-micro7 X-ray device manufactured by Rigaku Corporation, the obtained wire F was irradiated to the sample with CuKα rays generated at a voltage of 40 kV and a current of 20 mA for 1 minute. Then, an X-ray diffraction pattern was imaged, and a result of an imaging photograph of the X-ray diffraction pattern of the wire F in FIG. This result shows that the short carbon fibers are generally oriented in the long axis direction of the fiber wire. It was confirmed that the short carbon fibers were oriented at an orientation angle of 0 to 7 ° with respect to the major axis direction. Moreover, the tensile strength of the obtained wire F was 168 MPa.

Example 3 is an example of forming a wire using a commercially available recycled pellet of CFRTP. Using a desktop kneader MC15 equipped with a biaxial conical screw in the same direction (L / D = 7.8 to 19.1, screw inner diameter 12 to 9 mmΦ, screw length 172 cm), the temperature near the inlet is controlled by the Netherlands Xplore Instruments BV 290 ° C, middle barrel temperature set to 300 ° C, lower barrel temperature set to 310 ° C, screw rotation set to 20 rpm, CFRTP recycled pellets completely melted, one discharge nozzle with a discharge nozzle hole diameter of 0.75 mm Discharge from. Thereafter, it was allowed to fall naturally, and the wire was wound up (winding speed 12 m / min) to produce a wire having an average diameter of 0.5 ± 0.1 mmφ. The tensile strength of the obtained wire was 160 MPa. About the obtained wire F, the orientation state of the short carbon fiber was investigated with a digital microscope. In the wire F, it was confirmed that the carbon fibers C were oriented at an orientation angle of 0 to 7 ° with respect to the major axis direction of the wire.

The measurement results of the fiber length in the regenerated pellets and the wire are shown in FIGS. From these results, the average fiber lengths in the recycled pellets and the wire were calculated to be 313 μm and 279 μm, respectively. *

Evaluation was made regarding the workability and welding resistance of the workpiece surface of the wire obtained in Examples 2 and 3 above. The surface of the workpiece was mildly rusted without any scars. It was also confirmed that there was no breakage such as breakage of the CFRP wire. It was also confirmed that there was no adhesion of welds. There was no symptom that the hair ends of the wire spread. The work surface finish and welding resistance properties are useful, for example, as industrial brushes.

Example 4 is an example of a sheet material using the virgin CFRTP utilization wire obtained in Example 2. The wire manufactured from the virgin pellets obtained in Example 2 was dried at 80 ° C. for 8 hours, spread in one direction, and hot-pressed at 260 ° C. under a pressure of 5 MPa to obtain a length of 80 mm × width 100 mm × thickness. A 3 mm sheet material was produced. The obtained sheet material had a bending strength of 250 MPa and a bending elastic modulus of 12 GPa in a direction parallel to the spread wire, and had sufficient strength as an industrial material. In addition, a sheet material having a thickness of 5 mm to 100 mm (illustrated and not limited) can be produced by appropriately adjusting the amount of spread when hot pressing.

Example 5 is an example in which a sheet material is directly molded from a recycled pellet of CFRTP by a melt extruder. Using a desktop kneader MC15 equipped with a biaxial conical screw in the same direction (L / D = 7.8 to 19.1, screw inner diameter 12 to 9 mmΦ, screw length 172 cm), the temperature near the inlet is controlled by the Netherlands Xplore Instruments BV 290 ° C, middle barrel temperature set to 300 ° C, lower barrel temperature set to 310 ° C, screw rotation was set to 20 rpm, CFRTP recycled pellets were completely melted, discharge nozzle shape was 7-10 mm wide, thick The sheet was discharged from a slit-type discharge port having a thickness of 0.7 to 1 mm to obtain a flat sheet material. In the obtained sheet material, it was confirmed that the carbon fibers C were oriented at an orientation angle of 0 to 7 ° with respect to a specific direction (extrusion direction) of the sheet material. After drying at 80 ° C. for 8 hours, the sheet was spread in one direction and heat-pressed at 260 ° C. and a pressure of 5 MPa to prepare a sheet material having a length of 80 mm × width 100 mm × thickness 3 mm. The obtained sheet material had a bending strength of 250 MPa and a bending elastic modulus of 12 GPa in a direction parallel to the spread wire, and had sufficient strength as an industrial material. In addition, a sheet material having a thickness of 5 mm to 100 mm (illustrated and not limited) can be manufactured by appropriately adjusting the amount of spread when hot pressing.

The above embodiments are examples of preferred embodiments for carrying out the present invention. Further, in view of the disclosure of the present invention, those skilled in the art can make many improvements, changes, substitutions, deletions, additions and the like without departing from the gist of the present invention.

Carbon fiber reinforced resin extruded wire has industrial uses as a composite material, molding material, etc., further bound rope, knitted fabric, sheet material, plate, rod, crimped extruded material, knitting this extruded material, It is possible to process a new carbon fiber reinforced resin by overlapping, combining with the same material, or another material.

F ... Wire rod C ... Carbon fiber P ... Resin X ... Wire rod long axis direction 1-4 ...

Discharge nozzle

1a, 2a ... Circular hole 3a ... Linear hole 4a ... Circular hole 4b ・・・ Slit type discharge port

Claims

10 to 50 w / w% carbon fiber, which is a reinforcing short fiber having an average fiber length of 0.05 to 3 mm, and 50 to 90 w / w% resin, and the orientation angle of the carbon fiber with respect to the extrusion direction is 0 to 7 ° Extruded material made of carbon fiber reinforced resin.
The resin is polyamide (PA) resin, acrylonitrile-butadiene-styrene copolymer (ABS) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS) resin, polypropylene (PP) resin, polyetherimide (PEI). The extruded material made of carbon fiber reinforced resin according to claim 1, which is a resin), a polyethylene terephthalate (PET) resin, a polyether ether ketone (PEEK) resin, or a polyether ketone ketone (PEKK) resin.
3. The extruded material of carbon fiber reinforced resin according to claim 2, wherein the polyamide-based resin is at least one selected from nylon 6, nylon 610, and nylon 612.
The extruded material made of carbon fiber reinforced resin according to any one of claims 1 to 3, wherein the extruded material is a wire.
A sheet material comprising a wire material that is an extruded material made of carbon fiber reinforced resin according to claim 4.
A fiber reinforced resin pellet or carbon fiber reinforced resin crushed material containing 10 to 50 w / w% carbon fiber, which is a short fiber for reinforcement, in which the carbon fiber is randomly oriented is charged into a melt extruder, and the screw rotation speed is 10 Melting and extruding extruded material in which reinforcing short fibers containing 10 to 50 w / w% of carbon fiber having an average fiber length of 0.05 to 3 mm are oriented in the extrusion direction by melting and extruding the extruded material at ˜100 rpm An extrusion process;
A cooling and solidifying step for cooling and solidifying the extruded material melt-extruded;
With
The cooled and solidified extruded material is a wire or sheet material, carbon fibers which are reinforcing short fibers having an average fiber length of 0.05 to 3 mm are 10 to 50 w / w%, and resin is 50 to 90 w / w%. And a carbon fiber-reinforced resin extruded material characterized in that an orientation angle of the carbon fiber with respect to the extrusion direction is 0 to 7 °.
7. The method for producing an extruded material of carbon fiber reinforced resin according to claim 6, wherein, in the melt extrusion step, the melt resin is melt extruded within a range of Reynolds number Re of 10 −6 to 10, more preferably 10 −5 to 1. .
The carbon according to claim 6 or 7, further comprising a sheet material forming step in which the cooled and solidified extruded material is a wire material or a sheet material, the wire material or the sheet material is spread on a press machine, and formed into a sheet material by hot pressing. A method for producing a fiber-reinforced resin extruded material.
The pellets are polyamide (PA) resin, acrylonitrile / butadiene / styrene copolymer (ABS) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS) resin, polypropylene (PP) resin, polyetherimide ( PEI) resin, polyethylene terephthalate (PET) resin, polyetheretherketone (PEEK) resin, polyetherketoneketone (PEKK) resin filled with carbon fiber and reinforced to crush the carbon fiber reinforced resin, melting temperature 9. A pellet forming step produced by introducing the extruded material into a melt extruder having a semiflight type or full flight type screw at 200 to 320 ° C., extruding the extruded material, and cutting the extruded material. Of the carbon fiber reinforced resin extruded material according to any one of Production method.