JP2013221114A - Resin sheet made of carbon fiber composite resin material, resin molded product and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoformed article capable of achieving a properly shaped state using a composite sheet made of a carbon fiber and a thermoplastic resin, and a method for manufacturing the same.SOLUTION: A resin sheet is made of a carbon fiber composite resin material wherein 2-60% carbon fiber having an average fiber length of 0.1-10 mm is compounded with a thermoplastic resin and 65-95% carbon fiber is aligned along a single direction. A resin molded product is obtained by laminating a thermoplastic film on the resin sheet. A method for manufacturing the resin molded product comprises performing a pressing step of pressing the resin sheet, wherein the porosity of the resin sheet is reduced from a value (porosity B) within the range of 0.01-50% to a value (porosity A) within the range of 0.01-5% by the pressing step.

Description

  The present invention relates to a resin sheet made of a highly oriented carbon fiber composite resin material in which carbon fibers are blended with a thermoplastic resin, a resin molded product, and a method for producing the same.

  High-performance carbon fibers are said to have physical properties that are 1/4 the specific gravity and 10 times the specific strength compared to iron. In addition, it has excellent wear resistance, heat resistance, heat stretchability, acid resistance, and electrical conductivity. Especially, it uses the characteristics that its strength and elastic modulus are remarkably higher than those of ordinary synthetic polymers. It is widely used in various fields such as space use, construction / civil engineering use, sports / leisure use.

In recent years, due to soaring crude oil prices, environmental impact, and nuclear power plant issues, attention has been focused on efficient use of energy in consideration of energy conservation and CO ₂ emission control. Especially, the movement of people and goods such as trains, automobiles, motorcycles, and bicycles In the field of materials in the body, it is desired to reduce the weight while maintaining the strength and elastic modulus.

  Under these circumstances, fiber reinforced composite materials have been used in the past, but in recent years, composite materials of carbon fiber and resin have been particularly rapidly developed, and their application is not limited to automobile parts, but also for construction. There are a wide variety of large parts such as materials and reinforcing materials, and small parts such as precision equipment and electronic equipment. Accordingly, in the molded product, not only a simple planar shape but also a complicated structure such as a curved surface, a concavo-convex shape, or a drawing shape is required. Furthermore, application to various shapes such as superiority in price and physical properties is required.

  In addition, thermosetting resins have been used in conventional carbon fiber reinforced composite materials, but handling them requires very advanced technology and equipment. In addition, expensive equipment such as low-frequency equipment for storage at low temperatures and high-temperature and high-pressure equipment for autoclaves are required.

  Usually, when a carbon fiber reinforced composite material is applied to an application requiring high mechanical properties, a molded product reinforced with continuous carbon fibers is often used. However, such a molded product reinforced with continuous fibers is very restrained by weaving or bundling with carbon fibers. For this reason, when trying to support shaping to a complicated structure such as a curved surface, uneven shape, or drawn shape, the bundles and weaves of aligned carbon fibers are disturbed in the undulating portion and curved surface, especially carbon. As the strength and elastic modulus of the fiber increase, the carbon fiber cannot follow and there is a risk that problems such as a resin pool of a thermosetting resin may occur.

  Therefore, in order to improve the formability to a complicated structure such as a curved surface structure, a measure is taken to suppress the fiber restraint by cutting the carbon fiber short while allowing a decrease in strength. Further, instead of thermosetting resins that are very difficult to handle, thermoplastic resins that are easy to process later have been used. However, when carbon fibers are cut short, the mechanical properties are lowered, so the range in which a molded product can be applied has been limited. Also, the molding method is limited to injection molding.

  Patent Document 1 discloses a technique for improving the moldability of a drawn shape and a concavo-convex shape, and 300 μm is provided on one side of a prepreg laminate in which an uncured thermosetting resin is impregnated between continuous reinforcing fiber bundles. It is described that an effect of excellent formability is exhibited by arranging a thermoplastic resin sheet having a thickness of 10 mm and performing vacuum forming under reduced pressure. However, simply placing the thermoplastic resin sheet on one side will shape the part, but the reinforcing fiber bundles and the thermosetting resin part will not be able to handle complex shapes, and the prepreg laminate will When it is thick, the effect is not sufficient, such as poor formability.

  Patent Document 2 discloses a sheet-like substrate comprising a prepreg (I) obtained by impregnating a continuous reinforcing fiber bundle (B) with an uncured thermosetting matrix resin (A), and a thermoplastic resin (C). A method of manufacturing a composite material using (II), which includes at least the following steps (a) to (c) is disclosed.

(A) A plurality of prepregs (I) and a sheet-like substrate (II) are laminated so that the sheet-like substrate (II) exists between at least one layer of the prepreg (I). A step of producing (III).
(B) A step of adjusting the surface of the upper and lower molds for press molding to a temperature T satisfying the following formula (1) and disposing the laminated base material (III) inside the upper and lower molds.
Formula (1): T1 ≦ T ≦ T2
T1: Temperature at which the melt viscosity η1 of the sheet-like substrate (II) is 1 × 10 ⁶ Pa · s at a torque generated by a parallel plate of 20 mm in diameter of 0.005 J.
T2: a temperature at which the melt viscosity η2 of the sheet-like substrate (II) is 1 × 10 ⁴ Pa · s at a generated torque of 0.005 J by a 20 mm diameter parallel plate.
(C) A step of clamping the upper and lower molds to form and harden them into a desired shape.

  However, in a layer composed of a carbon fiber reinforced layer of a thermosetting matrix and a thermoplastic sheet, the thermosetting resin and the thermoplastic resin are completely bonded even if the temperature is lowered after the temperature is raised to the melting point of the thermoplastic sheet. Rather, the process is lengthened at the same time as the strength is reduced, resulting in costs and management due to storage of the matrix layer. Further, such a material is not suitable for processing into a complicated shape, and the effect is not sufficient, such as inferior formability when the prepreg laminate becomes thick.

  Patent Document 3 discloses a fiber reinforced composite material composed of at least the following components [A], [B], [C] and [D], and includes at least the components [A], [B] and The composite layer 1 composed of [C] and the composite layer 2 composed of at least the constituent elements [B], [C], and [D] are alternately formed. D] is included, and an average layer thickness of the composite layer 2 is 10 to 50 μm, and a fiber-reinforced composite material is disclosed.

[A] a carbon fiber bundle having 6,000 to 70,000 filaments,
[B] A cured product obtained by curing a thermosetting resin composition containing at least the following components [B-1] and [B-2],
[B-1] Thermosetting resin containing at least one selected from epoxy resin, cyanate resin, bismaleimide resin, benzoxazine resin,
[B-2] a component capable of curing the component [B-1],
[C] Core-shell polymer particles having a volume average particle diameter of 1 to 500 nm,
[D] An amorphous thermoplastic resin containing in the molecule at least one linking group selected from an amide group, a sulfonyl group, and an imide group.

  However, since the main component is a thermosetting resin, it is very difficult to form a complicated shape when post-processing in a state where one or more linking groups are contained. Furthermore, since the content ratio of the thermoplastic resin is small, it was difficult to melt and recycle by heating later.

  In Patent Document 4, a plurality of preforms including reinforcing short fibers and a thermoplastic resin are arranged in layers in a mold, and a molded body made of a fiber-reinforced thermoplastic resin is formed by heating and pressure molding. In the manufacturing method, techniques having the following characteristics a to d and g are disclosed.

a. As a mold, a mold having at least two divided molds is used.
b. Of the plurality of preforms, at least one unidirectional preform with reinforcing short fibers aligned in one direction is used,
c. After the unidirectional preform is placed adjacent to the cavity for molding the part of the mold where the unidirectional reinforcement is desired in the molded body,
d. Heat the mold to melt the thermoplastic resin of the preform and move the split mold relatively,
g. The reinforcing short fibers contained in the unidirectional preform are flowed together with the molten thermoplastic resin and oriented in the flow direction.

  In this method, at least one of a plurality of preforms containing a thermoplastic resin is heated after pressing using a unidirectional preform in which reinforcing short fibers are aligned in one direction. The flowing carbon fibers are oriented in one direction. For this reason, the force in a predetermined direction is durable, but the force from a different direction is weak, so that it may be easily cracked depending on the shape of the molded product.

Patent Document 5 describes a lamination method using preformed yarn. In this method, after filaments of thermoplastic fibers and preformed yarn are knitted into a woven fabric, the obtained sheet is overlaid on the final product C / C composite sheet by the required number, and this is hot-pressed for about 300 times. Molding is performed by applying a pressure of normal pressure to 300 kgf / cm ² under a temperature condition of ˜900 ° C. Next, the molded article is carbonized at a temperature of about 700 to 1200 ° C. and further graphitized at a temperature of about 1500 to 3000 ° C. to obtain a C / C composite. However, according to this method, since the thermoplastic resin is thermally decomposed and vaporized after carbonization, it cannot be corrected once the shape is formed. Furthermore, since there is no thermoplastic resin left, it is very difficult to recycle.

JP 2007-291204 A JP 2008-230236 A JP 2010-189561 A Japanese Patent No. 2773261 Japanese Patent No. 3272852

  An object of the present invention is to provide a resin sheet made of a carbon fiber composite resin material and a resin molded product that can be well shaped using the resin sheet, in view of the problems of the prior art.

  In order to achieve the above object, a resin sheet according to the present invention, a resin molded product, and a manufacturing method thereof have the following configurations.

(1) Carbon fiber having an average fiber length (number average) of 0.1 to 10 mm is blended in the thermoplastic resin at a rate of 2 to 60%, and the carbon fiber is at a rate of 65 to 95% along one direction. A resin sheet comprising an oriented carbon fiber composite resin material.

(2) It is comprised from the flat plate which consists of a plurality of the said carbon fiber composite resin material which has a thickness of 0.05-10 mm per sheet | seat, The said carbon fiber is a ratio of 65-95% along the one-side direction of the said flat plate. The oriented resin sheet (1).

(3) The resin sheet according to (2), wherein the flat plates are laminated so that the carbon fibers are oriented in different directions between the flat plates in contact with each other.

(4) The resin sheet according to (2) or (3), wherein the flat plate extends so that the carbon fibers are oriented along different directions between the flat plates in contact with each other.

(5) The resin sheet of (2) to (4), wherein the flat plate formed in a belt shape is knitted in a lattice shape.

(6) The resin sheet of (1) to (5) having a porosity of 0.01 to 5%.

(7) A resin molded product, wherein a thermoplastic film is laminated on the resin sheet of (1) to (6) above.

(8) A method for producing a resin molded product, wherein the pressing step of pressing the resin sheet of the above (1) to (5) is performed, wherein the porosity of the resin sheet is 0.01 to 50% by the pressing step. A method for producing a resin molded product, wherein the value is reduced from a value within the range (voidage B) to a value within the range of 0.01 to 5% (voidage A).

(9) The method for producing a resin molded product according to (8), wherein the pressing step is performed in a state where the surface temperature of the resin sheet is higher by 10 to 100 ° C. than the melting point of the thermoplastic resin.

(10) The method for producing a resin molded product according to (9), wherein a heating step for heating the resin sheet is performed in combination with the pressing step.

(11) The method for producing a resin molded product according to (9) or (10), wherein a heating step of heating the resin sheet is performed before the pressing step.

  By using the resin sheet of the present invention, the carbon fiber composite resin material can be shaped into a complicated shape during press molding. Further, by laminating or extending the carbon fibers so that they are oriented along different directions, a resin molded product having excellent mechanical properties can be obtained.

  Furthermore, the external appearance design can be enhanced by bonding a separately produced thermoplastic film onto the resin sheet. In addition, since most of the resin sheet forming material is a thermoplastic resin, it can be easily recycled.

It is a schematic perspective view of the resin sheet which concerns on one embodiment of this invention, (a) is a single layer sheet, (b) is a 2 layer laminated sheet, (c) shows a 4 layer laminated sheet. It is a schematic perspective view which shows the flat sheet as a material used in order to manufacture the resin sheet of Fig.1 (a)-(c). It is a partial expansion schematic perspective view which shows the orientation state of the carbon fiber in the resin sheet of Fig.1 (a)-(c). FIG. 3 is a schematic cross-sectional configuration diagram illustrating an apparatus for manufacturing the flat sheet of FIG. 2. It is a schematic perspective view for demonstrating the process of cut | disconnecting the flat sheet of FIG. 2 to a longitudinal direction. It is a schematic perspective view of the resin sheet which concerns on the other embodiment of this invention, (a) is a 1 layer extended sheet, (b) is a 2 layer extended sheet, (c) is a 4 layer extended sheet. Indicates. It is a schematic perspective view which shows the flat sheet as a material used in order to manufacture the resin sheet of Fig.6 (a)-(c). It is a schematic perspective view of the resin sheet which concerns on other embodiment of this invention, (a) is 1 layer lattice knitting sheet, (b) is 2 layers lattice knitting sheet, (c) is 4 layers lattice knitting. Indicates a sheet. It is a schematic perspective view which shows the flat sheet as a material used in order to manufacture the resin sheet of Fig.8 (a)-(c). It is a flowchart for demonstrating the manufacturing method of the resin molded product which concerns on one embodiment of this invention, (a) is a flat sheet as a material, (b) is the lamination process which laminates | stacks a flat sheet in a metal mold | die, (C) is a heating step for heating the flat sheet during pressing, (d) is an opening step for opening after the mold is cooled, and (e) is a resin molded product obtained by fluid press hot pressing. It is a flowchart for demonstrating the manufacturing method of the resin molded product which concerns on the other embodiment of this invention, (a) is the heating process which heats the flat sheet as a material, (b) is a flat sheet in a metal mold | die. (C) is a pressing process for pressing a flat sheet with a mold, (d) is an opening process for opening the mold, and (e) is a resin molded product obtained by non-fluid molding hot pressing. Show. It is a flowchart for demonstrating the hot press method in the manufacturing method of the resin molded product which concerns on the further another embodiment of this invention, (a) is the 1st heating process which heats the flat sheet as a material, (b). Is a laminating process for laminating a flat sheet in a mold, (c) is a pressing process for pressing the flat sheet with a mold, (d) is a second heating process for heating the flat sheet being pressed, (e) is a metal mold The opening process which opens a type | mold is shown. It is a flowchart for demonstrating the hot press method of the manufacturing method of the resin molded product which concerns on a prior art, (a) is the 1st heating process which heats the flat sheet as a material, (b) is a flat sheet to a metal mold | die. (C)-(d) shows the press process which presses a flat sheet with a metal mold | die, (e) shows the open process which open | releases a metal mold | die.

  Hereinafter, the resin sheet of the present invention, the resin molded product, and the manufacturing method thereof will be specifically described.

  A resin sheet (single layer sheet 1) as a unit constituting a resin sheet made of a carbon fiber composite resin material has an appearance as shown in FIG. 1 (a), and the carbon fiber is 2 to 60% of the thermoplastic resin. The carbon fibers are blended at a ratio, and the carbon fibers are oriented in a ratio of 65% to 95%, preferably 75% to 90% in the longitudinal direction of the sheet. The length of the carbon fiber is preferably 0.1 mm to 10 mm, and more preferably 0.1 mm to 3 mm. The impregnation ratio of the thermoplastic resin is preferably 5% to 60%, and more preferably 15% to 40%. The thickness of the single layer sheet 1 is preferably 0.05 mm to 10 mm, and more preferably 0.1 mm to 2 mm.

Many methods for measuring the orientation state of the carbon fibers in the resin sheets 1 to 3 as shown in FIG. 3 (the orientation direction 10 of the carbon fibers is indicated by a broken line) are already known. There is description in -160257 gazette. Observing the cross section in the transverse direction of the sheet, it can be seen that the cross section of the fiber is elliptical. When the length of the major axis of the ellipse is b, the length of the minor axis is a, and the inclination of the cross section with respect to the reinforcing direction of the FRP is θ, the inclination α of the fiber from the reinforcing direction is α = | θ−cos ^−1. (A / b) | There is also a method of measuring the orientation angle and the state of waviness by obtaining α for all or some of the fibers and performing statistical processing. Here, the degree of orientation of carbon fibers is measured by using VG Studio MAX (Japan Visual Science) using a Shimadzu Microfocus X-ray CT system (SMX-100CT) and searching for the fiber length. Exact Analysis for Fiber (Japan Visual Science) Analyzed using.

  Moreover, when manufacturing a resin sheet, the chip | tip manufactured by the method described in the following (A)-(C) is used.

(A) After a bundle of 100 to 100,000 carbon fibers impregnated with a thermoplastic resin is converged with a sizing agent comprising a thermosetting resin or a thermosetting resin, a low viscosity thermoplastic resin is used. Coat and cut this into 3 to 10 mm lengths to make chips. Thus, the chip | tip arrange | positioned in the form which converged the bundle | flux of the carbon fiber in the axial center direction can also be manufactured by the method described in Unexamined-Japanese-Patent No. 2002-187127 or 2006-175787, for example.

(B) Using a twin-screw extruder, the thermoplastic resin and the cut carbon fiber are introduced from a hopper, melt-mixed, and then discharged through a die having a plurality of round holes with a diameter of 2 to 4 mm. After water cooling or air cooling, This is cut into a length of 3 to 10 mm to form a chip. In this chip, fibers are randomly oriented in the chip.

(C) Using a twin-screw extruder, after the thermoplastic resin is charged from the hopper, the bobbin-wrapped carbon fiber filament is charged and mixed in the vicinity of the middle of the screw in a state where the resin is sufficiently melted. It is discharged through a die having a plurality of round holes having a diameter of ˜4 mm, and after water cooling or air cooling, this is cut into a length of 3 to 10 mm to form a chip. In this chip, fibers are randomly oriented in the chip.

  Chips produced by the methods (A) to (C) are introduced from the hopper of an extruder, and carbon is melted in the range of the melting point of the thermoplastic resin +10 to 40 ° C. with a single or twin screw extruder. It discharges through the die | dye opened to the rectangle of 0.5 mm-5 mm of short sides, opening a fiber bundle.

  In addition, when throwing a chip | tip into a hopper, the thermoplastic resin from which a component differs, or the thermoplastic resin from which a viscosity is different also in the same component can be thrown in, and a viscosity adjustment and the content rate of carbon fiber can also be controlled.

  A thermoplastic resin containing carbon fibers discharged from a die and defibrillated is sandwiched between two or more rolls adjusted to a constant temperature, or sandwiched between stainless steel belts and heated and compressed. A resin sheet is obtained.

  In the obtained resin sheet, the apparent density C was measured with an Extron Tech high precision electronic hydrometer EW-300SG.

  The true density D of the resin sheet is D = 100 × F × H / (E × F + G, where E is the carbon fiber content, F is the carbon fiber density, G is the thermoplastic resin content, and H is the thermoplastic resin density. XH).

  At this time, in the resin sheet, the apparent density C is in the range of 98% to 60% of the true density D, preferably 98% to 80%, and more preferably 98% to 90%.

  There is a method of calculating the porosity from the true density and the bulk density, but here, the porosity was measured using X-ray analysis. In addition, a porosity measuring method and measuring instrument described in Japanese Patent No. 2945745 are also known.

  The porosity of the obtained resin sheet is preferably within a range of 0.01% to 50%, more preferably 1% to 30%, and further preferably 2% to 15%.

  The thermoplastic resin used for the production of the resin sheet may be a polyolefin (for example, polyethylene, polypropylene, polybutylene, polystyrene) or a polyamide (for example, nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, aromatic nylon). , Polyimide, polyamideimide, or polycarbonate, or polyester (eg, polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate), polyphenylene sulfide, polysulfoxide, polytetrafluoroethylene, acrylonitrile butadiene styrene copolymer, polyacetal, poly Ether, polyether ether ketone, and polyoxymethylene may be used. Furthermore, a derivative of the thermoplastic resin, a copolymer of the thermoplastic resin, or a mixture thereof may be used.

  Moreover, as shown in FIGS. 1B to 1C, the orientation direction of the carbon fibers between the sheets in which two or more, more preferably four or more flat sheets made of a resin material are laminated and in contact with each other. Are preferably crossed vertically and horizontally. The orientation of the carbon fibers in the laminated and hot-pressed resin sheet (laminated sheet) intersects the cross, so that in the laminated sheet, the carbon fibers are randomly oriented without any vertical or horizontal orientation. Going up, there will be fewer week points.

  Furthermore, as shown to Fig.6 (a)-(c), it arrange | positions flat sheet | seats, making an orientation direction cross | intersect on the plane vertically and horizontally, and has a resin sheet (extension) of 1 times-100 times the area of a flat sheet Sheet) can be manufactured. A desirable size from the viewpoints of practicality and versatility is 1 to 20 times, or 1 to 10 times the area of one flat sheet.

  Further, as shown in FIG. 8 (a), the flat sheet is cut into a strip shape (ribbon shape) and knitted in a lattice shape while crossing the orientation directions vertically and horizontally, as shown in FIGS. 8B to 8C. May be laminated as necessary. Here, the band (ribbon) is obtained by slitting (cutting) a flat sheet in the longitudinal direction with an electric round blade cutter or a cutter. The length of the band is not particularly limited, but the length of the band is preferably 200 mm to 1,000,000 mm, more preferably 200 mm to 50,000 mm, or 200 mm to 5,000 mm in order to knit in a lattice shape. The width of the band is preferably 5 mm to 200 mm, more preferably 10 mm to 50 mm.

  In the resin sheet, the apparent density I was measured with an Extron Tech high precision electronic hydrometer EW-300SG.

  The true density J of the resin sheet is J = 100 × L × N / (K × L + M, where K is the carbon fiber content, L is the carbon fiber density, M is the thermoplastic resin content, and N is the thermoplastic resin density. × N). At this time, the apparent density I of the resin sheet is 100% to 85% of the true density D, preferably 100% to 95%, and more preferably 100% to 97%.

  The hot press method can be broadly divided into a fluid molding method and a non-fluid molding method, and any of these molding methods can be adopted, and can be used properly depending on the application, production rate, yield, and the like.

  In the fluid molding type hot press, after flat sheets are stacked so that the carbon fiber orientation directions of the sheets in contact with each other intersect vertically and horizontally, and placed in the press mold (upper mold, lower mold) After the mold is closed and a pressure of 1 MPa to 30 MPa is applied, the mold is heated to a temperature 10 ° C. to 100 ° C. higher than the melting point of the thermoplastic resin, preferably 20 to 60 ° C. higher than the melting point of the thermoplastic resin. When using an amorphous thermoplastic resin, it is preferable to heat to glass transition temperature +20 degreeC-200 degreeC. At this time, it is necessary to heat so that heat is sufficiently transmitted to the inside of each flat sheet.

  Subsequently, after cooling to below the resin solidification temperature, the mold is opened to obtain a molded product of the resin sheet that is hot pressed. What is necessary is just to adjust suitably the heating time of a metal mold | die, press time, and cooling time according to the progress of melting and solidification of a thermoplastic resin. The mold may be preheated in a temperature range from a temperature 50 ° C. lower than the melting temperature of the thermoplastic resin to a temperature 100 ° C. higher than the melting temperature of the thermoplastic resin.

  In the non-fluid molding hot press, the flat sheet is heated to a temperature 10 to 100 ° C. higher than the melting point of the thermoplastic resin, preferably 20 to 60 ° C. higher than the melting point of the thermoplastic resin. When using an amorphous thermoplastic resin, it is preferable to heat to glass transition temperature +20 degreeC-200 degreeC. At this time, it is necessary to be heated so that heat is sufficiently transmitted to the inside of the flat sheet.

  Furthermore, a flat sheet heated in the upper and lower molds of the press machine is laminated so that the contacting sheets cross each other in the vertical and horizontal directions of the carbon fiber, and a pressure of 1 MPa to 30 MPa is applied. After that, the mold is opened to obtain a molded product of the heat-pressed resin sheet. What is necessary is just to adjust suitably the heating time of a metal mold | die, press time, and cooling time according to the progress of melting and solidification of a thermoplastic resin. Moreover, it is preferable to heat a metal mold | die beforehand to the temperature lower 50 to 30 degreeC than the solidification temperature of a thermoplastic resin. If the temperature of the mold is higher than the melting point by 150 ° C. or more, the resin is difficult to cool and the sheet may not be solidified. Moreover, there exists a possibility that a molded article may decompose | disassemble above the decomposition temperature of resin.

  The fluid molding type hot press is effective in obtaining a product having a more complicated structure or a thin wall because the resin flows inside the mold.

  The non-fluid molding type hot press is effective in obtaining a simple structure and a thick product because the fluidity of the resin is small.

  The number of laminated flat sheets may be appropriately determined depending on the cavity thickness of the mold and the state of the heated resin.

  Furthermore, in order to obtain a resin molded product by laminating a thermoplastic film on the upper surface, lower surface, or both upper and lower surfaces of the resin sheet obtained by the above method, for example, thermoplastic on the upper surface, lower surface, or both upper and lower surfaces of the resin sheet. The film can be heat-bonded in the mold with the films laminated. At this time, the thermoplastic film may be adhered to the resin sheet with an adhesive or ultrasonic waves before and after molding, or may be thermally bonded again.

  4 is a schematic cross-sectional configuration diagram showing an apparatus for producing the flat sheet 4 in FIG. A roll in which a resin material 33 impregnated with a low-viscosity thermoplastic resin in a carbon fiber is subjected to a uniaxial or biaxial extruder by melt extrusion molding, and the resin material 33 extruded from a die 32 having a narrow gap is heated. 34 (which may be a heated stainless steel belt press) to obtain a flat sheet 36. That is, by extruding the resin material 33 from the narrow gap, the carbon fibers in the resin material 33 are forcibly arranged along the flow direction of the resin material 33, but the carbon fibers are free in the low-viscosity resin. Spring back and spread the resin. As a result, the resin material 33 includes a lot of voids. Therefore, it is possible to obtain a flat sheet 36 that is forcibly formed into a sheet by being sandwiched between heated rolls 34 that are heated before the resin is solidified.

  At this time, a flat sheet 36 in which some 1% to 10% voids remain and the carbon fibers are strongly oriented in the flow direction is obtained. Since the flat sheet 36 itself has a relatively large number of air gaps, it can be separately hot-pressed or pressed with a heated stainless steel belt in order to improve practicality. However, in the flat sheet 36 itself, since the fibers are arranged in the vertical direction, the physical properties in the vertical direction, the tensile strength, the bending strength, and the like are very strong, but conversely, they are relatively weak in the width direction. Furthermore, although the strength in the width direction is maintained as compared with a simple thermoplastic resin, if the flat sheet 36 has a large number of voids, the physical properties tend to decrease. For example, the flat sheet 36 has two or more layers, preferably four layers. The flat sheets 36 are stacked in the vertical and horizontal directions so that the orientation directions of the carbon fibers between the upper and lower flat sheets cross vertically and horizontally.

  When the flat sheet 36 is thermocompression-bonded by the two hot pressing methods such as fluid molding and non-fluid molding as described above, the carbon fibers are oriented in a lattice pattern on the plane, and both the longitudinal and lateral strengths are improved.

  Further, as shown in FIG. 7A, a plurality of flat sheets 36 are laid out on a plane and arranged, and the orientation of the flat sheets 36 is set to the vertical direction so that the orientation directions of carbon fibers of adjacent sheets intersect vertically and horizontally. Stagger in the horizontal direction. In a state where the plurality of flat sheets 36 are arranged on a plane, as shown in FIGS. 7B to 7C, for example, two or more layers, more preferably four or more layers are laminated, and the upper and lower sheets are made of carbon. The orientation of the flat sheet 36 is alternated between the vertical direction and the horizontal direction so that the fiber orientation directions intersect in the vertical and horizontal directions.

  As a result, a sheet having an area larger than the unit area of the flat sheet 36 can be produced. Furthermore, the strength reduction of the joints can be suppressed by stacking portions adjacent to each other or by stacking the joints of the flat sheet 36 so that the joints of the flat sheet 36 are not in the same position in the upper and lower layers.

  Further, as shown in FIG. 5, the flat sheet 36 is cut into a strip shape, and the strips are combined in a lattice shape as shown in FIGS. ), The orientation of the carbon fibers is arranged vertically and horizontally, and the joints are folded. Further, by preventing the joints of the bands knitted in a lattice form from being formed at the same position in the upper and lower layers, it is possible to suppress a decrease in strength of the joints.

In each example and comparative example, the test conditions are basically the same as those in example 1 except for the test conditions specifically indicated. Unless otherwise specified, the carbon fiber content in the resin sheet is equal to the carbon fiber content in the chip used, the carbon fiber density is 1.80 g / cm ³ , and the thermoplastic resin content in the resin sheet Is equal to a value obtained by subtracting “% of carbon fiber content in resin sheet” from 100%. Thermoplastic resin density in the resin sheet, 1.14 g / cm ³ with nylon 6, 1.14 g / cm ³ nylon 66, polypropylene 0.90 g / cm ^3, with acrylonitrile-butadiene-styrene copolymer (ABS) 1.05 g / cm ^3, a 1.35 g / cm ³ in polyphenylene sulfide (PPS).

Example 1
As shown in FIG. 4, a chip containing 30% carbon fiber having an average fiber length (number average) of 1 mm in nylon 6 is put into a single-screw extruder, kneaded at 250 ° C., and measured with a gear pump. A molten carbon fiber composite resin material 33 is poured into a simple die 32 (opening size: 2 mm × 200 mm). The discharged resin material 33 was allowed to flow between two heated nip rolls 34 having a width of 1 mm between rolls heated by a heater at 150 ° C. to obtain a flat sheet 36 having a product width of 210 mm and a thickness of 1.05 mm. The flat sheet 36 was cut at 1000 mm in the vertical direction and cut into an ear width of 200 mm.

  The obtained flat sheet 36 had a porosity (void ratio B) of 8.07%. The orientation rate of the carbon fibers was 92% in the longitudinal direction.

  In measuring the bending strength, a Tensilon tensile tester (RTF-1350) was used according to JIS standard K7161. The measured bending strength was 330 MPa in the vertical direction and 200 MPa in the horizontal direction.

  The obtained flat sheet 36 is cut into a size of 200 mm × 200 mm, and the two flat sheets 5 shown in FIG. 2B are heated with a far-infrared heater at 280 ° C. for 5 minutes as shown in FIG. Then, the two stacked flat sheets 5 are placed in a 200 mm × 200 mm mold whose temperature is adjusted with warm water of 80 ° C. so that the carbon fiber orientation is perpendicular to the length and width.

  The flat sheet 5 is pressed at 10 MPa for 5 minutes using the mold 83, and the mold 83 is opened to obtain a two-layer resin sheet (laminated sheet 2) shown in FIG. The laminated sheet 2 is a hot press-molded product having a size of 200 mm × 200 mm, a thickness of 1.96 mm, and a porosity (void ratio A) of 0.51%. The bending strength was 410 MPa and 400 MPa, respectively, with no significant difference between the longitudinal direction and the lateral direction.

(Example 2)
Laminating four sheets obtained by cutting the flat sheet 36 described in Example 1 into a size of 200 mm × 200 mm, and in the mold 83 of 200 mm × 200 mm so that the fiber orientation is perpendicular to the vertical and horizontal between the upper and lower adjacent sheets, Four flat sheets 6 shown in FIG. 2C are arranged.

  The mold 83 is preheated to 250 ° C. with a heater, the mold 83 is closed, the flat sheet 6 is pressed at 12 MPa for 5 minutes, and then cooled to 100 ° C. or lower with cold water. By opening the mold 83, a four-layer resin sheet (laminated sheet 3) shown in FIG. 1C is obtained. The laminated sheet 3 is a hot press-formed product having a size of 200 mm × 200 mm, a thickness of 3.94 mm, and a porosity (void ratio A) of 0.31%. The bending strength was 420 MPa and 415 MPa with no significant difference in the vertical and horizontal directions.

(Example 3)
The flat sheet 36 described in Example 1 is cut into a size of 200 mm × 200 mm, and the flat sheet 4 is placed in a 200 mm × 200 mm mold 83 in a non-laminated state as shown in FIG. .

  The mold 83 is preheated to 250 ° C. with a heater, the mold 83 is closed, the flat sheet 4 is pressed at 12 MPa for 5 minutes, and then cooled to 100 ° C. or lower with cold water. By opening the mold 83, the resin sheet (single layer sheet 1) shown in FIG. The single-layer sheet 1 is a hot press molded product having a size of 200 mm × 200 mm, a thickness of 0.98 mm, and a porosity (void ratio A) of 0.30%. The bending strength was 370 MPa in the vertical direction and 260 MPa in the horizontal direction.

Example 4
A chip containing 25% of carbon fiber having an average fiber length of 5 mm in nylon 66 is put into a single-screw extruder and poured into a die 32 while being kneaded at 290 ° C. and measured with a gear pump. The discharged carbon fiber-containing resin was caused to flow between two rolls 34 having a width of 1 mm between rolls heated by a heater at 180 ° C. to obtain a flat sheet 36 having a product width of 210 mm and a thickness of 1.03 mm. The flat sheet 36 was cut into a size of 200 mm in the vertical direction and cut into an ear width of 200 mm.

  The obtained flat sheet 36 had a porosity (void ratio B) of 7.28%. The orientation rate of the carbon fibers was 90% in the vertical direction, and the bending strength was 390 MPa in the vertical direction and 250 MPa in the horizontal direction.

  As shown in FIG. 7B, 12 sheets obtained by cutting the obtained flat sheet 36 into a size of 200 mm × 200 mm are laminated in two layers of 6 sheets on the top and 6 sheets on the bottom. Two stacked flat sheets 48 arranged in a 600 mm × 400 mm mold are arranged so that the fiber orientations are perpendicular to each other between adjacent sheets.

  The mold is heated in advance to 310 ° C. with a heater, the mold is closed, pressed at 12 MPa for 5 minutes, and then cooled to 100 ° C. or lower with cold water. By opening the mold, a two-layered resin sheet (laminated sheet 51) obtained by heat-pressing the six sheets as shown in FIG. 6B is obtained. The laminated sheet 51 is a hot press molded product having a size of 600 mm × 400 mm, a thickness of 1.92 mm, and a porosity (void ratio A) of 0.38%. The bending strength was 480 MPa and 460 MPa with no significant difference in the vertical and horizontal directions.

(Example 5)
Twenty-four flat sheets 36 cut into a size of 200 mm × 200 mm described in Example 4 were heated with a far-infrared heater at 310 ° C. for 5 minutes, and as shown in FIG. Two flat sheets 49 are stacked and placed in a 600 mm × 400 mm mold so that the fiber orientation is perpendicular to the vertical and horizontal directions between adjacent sheets in the vertical and horizontal directions. By pressing the mold at 10 MPa for 5 minutes and opening the mold, as shown in FIG. 6 (c), a two-layered resin sheet (laminated sheet 52) obtained by arranging and heating the six sheets is obtained. The laminated sheet 52 is a hot press-molded product having a size of 600 mm × 400 mm, a thickness of 3.86 mm, and a porosity (void ratio A) of 0.53%. The bending strength was 485 MPa and 470 MPa with no significant difference in the vertical and horizontal directions.

(Example 6)
A chip containing 20% carbon fiber having an average fiber length of 0.8 mm in ABS is put into a single-screw extruder, kneaded at 230 ° C., and poured into a die 32 while being measured by a gear pump. The discharged resin material 33 containing carbon fibers was passed between two rolls 34 having a width of 1 mm between rolls heated by a heater at 100 ° C. to obtain a flat sheet 36 having a product width of 216 mm and a thickness of 0.95 mm. The flat sheet 36 was cut to a length of 1000 mm in the vertical direction and cut to an ear width of 200 mm.

  The obtained flat sheet 36 had a porosity (void ratio B) of 8.33%. The orientation rate of the carbon fibers was 94% in the vertical direction, and the bending strength was 150 MPa in the vertical direction and 110 MPa in the horizontal direction.

  As shown in FIG. 5, the obtained one-layer flat sheet 36 is cut into a strip-shaped flat sheet 38 of 50 mm × 1000 mm with a rotary blade 39, and the rest is cut into a lattice shape. The flat sheet 61 knitted in a lattice shape is heated for 5 minutes by a far-infrared heater at 260 ° C., and as shown in FIG. 9B, in a 400 mm × 400 mm mold in a lattice shape so as to be orthogonal to the length and width. A knitted two-layer flat sheet 62 is arranged. A flat sheet 62 is pressed with a mold at 10 MPa for 5 minutes, and the mold is opened, and as shown in FIG. 8 (b), a hot-pressed four-layer resin sheet (grid knitted sheet) knitted into a lattice shape 65) is obtained. The lattice knitted sheet 65 is a hot press-molded product having a size of 400 mm × 400 mm, a thickness of 3.54 mm, and a void ratio (void ratio A) of 0.43%. The bending strength was 250 MPa and 240 MPa with no significant difference in the vertical and horizontal directions.

(Example 7)
The strip-shaped flat sheet 38 described in Example 6 is knitted in a lattice shape, and the rest is cut. Using this flat sheet 38 knitted in a lattice shape, as shown in FIG. 9C, a four-layer flat sheet knitted in a lattice shape in a 400 mm × 400 mm mold so as to be orthogonal to the length and breadth. 63 is arranged. The mold is preheated to 230 ° C. with a heater, the mold is closed, the flat sheet 63 is pressed at 12 MPa for 5 minutes, and then cooled to 100 ° C. or lower with cold water. By opening the mold, as shown in FIG. 8C, a heat-pressed eight-layer resin sheet (grid knitted sheet 66) knitted in a lattice shape is obtained. The lattice knitted sheet 66 is a hot press-molded product having a size of 400 mm × 400 mm, a thickness of 7.02 mm, and a porosity (void ratio A) of 0.32%. The bending strength was 255 Pa and 250 MPa with no significant difference in the vertical and horizontal directions.

(Example 8)
As shown in FIG. 10, two sheets obtained by cutting the flat sheet 36 described in Example 1 into a size of 200 mm × 200 mm are stacked, and the total area is 285 mm so that the fiber orientation is orthogonally crossed vertically and horizontally between adjacent sheets above and below. Between the press upper mold | type 71 and the press lower mold | type 72 which comprise the metal mold | die which has a * 210 mm box-shaped nest | insert, the 2 sheets of flat sheet 5 is arrange | positioned, and a metal mold | die is closed.

  The mold is heated in advance to 250 ° C. with a heater, and the flat sheet 5 is pressed at 12 MPa for 5 minutes in a closed press mold 73 and then cooled to 100 ° C. or lower with cold water. By opening the mold, a box-shaped hot press molded product 78 made of a carbon fiber composite resin material and having a curved surface portion is obtained. The thickness is 1.21 mm, and the void ratio (void ratio A) is 0.11%. The bending strength was 405 MPa.

Example 9
As shown in FIG. 11, four flat sheets 36 cut into a size of 300 mm × 200 mm described in Example 4 were heated for 5 minutes with a far-infrared heater at 310 ° C., laminated in two layers, and adjacent to the upper, lower, left, and right sides. A flat sheet 5 in which two sheets are stacked between an upper press mold 71 and a lower press mold 72 constituting a mold having a box-shaped nesting with a total area of 285 mm × 210 mm so that the fiber orientation is perpendicular to the vertical and horizontal directions between the sheets to be pressed Place and close the mold. Further, a polyester sheet 68 having a thickness of 0.1 mm on which metal thin films are arranged is stacked on the flat sheet 5, the mold is pressed at 10 MPa for 5 minutes, and the mold is opened to provide carbon having a metallic luster on the surface. A box-shaped hot press molded product 79 made of a fiber composite resin material and having a curved surface portion was obtained. This hot press-molded product 79 had a thickness of 1.22 mm, a porosity (void ratio A) of 0.62%, and a bending strength of 420 MPa.

(Example 10)
Chips containing 30% carbon fiber with an average fiber length of 2 mm in polypropylene are put into a single-screw extruder and poured into a die 32 while being kneaded at 210 ° C. and measured with a gear pump. The discharged resin material 33 containing carbon fibers was passed between two rolls 34 having a width of 1 mm between rolls heated by a heater at 80 ° C. to obtain a flat sheet 36 having a product width of 215 mm and a thickness of 1.08 mm. The flat sheet 36 was cut to a length of 1000 mm in the vertical direction and cut to an ear width of 200 mm. The obtained flat sheet 36 had a porosity (void ratio B) of 2.56%. The orientation rate of the carbon fibers was 89% in the longitudinal direction. The bending strength was 80 MPa in the vertical direction and 50 MPa in the horizontal direction.

  The obtained polypropylene flat sheet 36 was cut into a size of 200 mm × 200 mm, stacked two times, and heated with a two-layer flat sheet 5 of nylon 6 described in Example 1 with a far-infrared heater at 280 ° C. for 5 minutes. Then, a total of four sheets are stacked and placed in a 200 mm × 200 mm mold whose temperature is adjusted with hot water at 80 ° C. so that the orientation of the carbon fibers is perpendicular to the length and breadth.

  The flat sheet is pressed with a mold at a pressure of 10 MPa for 5 minutes, and the mold is opened to obtain a four-layer resin sheet (laminated sheet 3). The laminated sheet 3 is a hot press-formed product having a size of 200 mm × 200 mm, a thickness of 1.99 mm, and a porosity (void ratio A) of 0.32%. The bending strength was 310 MPa and 290 MPa with no significant difference in the vertical and horizontal directions.

(Example 11)
A chip containing 30% carbon fiber having an average fiber length of 0.5 mm in polyphenylene sulfide is put into a single screw extruder, kneaded at 340 ° C., and poured into a die 32 while being measured by a gear pump. The discharged resin material 33 containing carbon fibers was caused to flow between two rolls 34 having a width of 1 mm between rolls heated by a heater at 200 ° C. to obtain a flat sheet 36 having a product width of 212 mm and a thickness of 1.08 mm. The flat sheet 36 was cut to a length of 1000 mm in the vertical direction and cut to an ear width of 200 mm. The resulting flat sheet 36 had a porosity (void ratio B) of 7.07%. The orientation rate of the carbon fibers was 88% in the longitudinal direction. The bending strength was 580 MPa in the longitudinal direction and 350 MPa in the transverse direction.

  The obtained polyphenylene sulfide flat sheet 36 was cut into a size of 200 mm × 200 mm, heated with a far-infrared heater at 380 ° C. for 5 minutes, and the four sheets were stacked as shown in FIG. Four stacked flat sheets 6 are placed in a 250 mm × 250 mm mold whose temperature is adjusted to 130 ° C. with a heater so that the orientation is perpendicular to the length and breadth.

  The flat sheet 6 is pressed with a mold at 20 MPa for 5 minutes, and the mold is opened to obtain a four-layer resin sheet (laminated sheet 3). The laminated sheet 3 is a hot press-molded product having a thickness of 1.61 mm and a void ratio (void ratio A) of 0.34%. The bending strength was 730 MPa and 720 MPa with no significant difference in the vertical and horizontal directions.

(Comparative Example 1)
Injection molding was performed using the chip described in Example 1, and a flat sheet 90 having a length of 100 mm, a width of 100 mm, and a thickness of 1.04 mm was produced using a side gate. The porosity of the flat sheet 90 was 1.23%. The orientation rate of the carbon fibers was 55% in the longitudinal direction with a radial tendency. The bending strength was as low as 180 MPa in the longitudinal direction and 170 MPa in the transverse direction, which is probably because the carbon fiber was cut during molding.

  As shown in FIG. 13, four sheets of the obtained flat sheet 90 were heated with a far-infrared heater at 280 ° C. for 5 minutes, these four sheets were stacked in two layers, and the temperature was adjusted with hot water at 80 ° C. 200 mm × 200 mm The metal mold is disposed between the upper mold 81 and the lower mold 82.

  With the mold 83 closed, the flat sheet 90 is pressed at a pressure of 10 MPa for 5 minutes, and the mold is opened to obtain a resin sheet (extended sheet 91). The extended sheet 91 is a hot press-molded product having a size of 200 mm × 200 mm, a thickness of 2.07 mm, and a porosity of 1.29%. The bending strength was 170 MPa and 155 MPa with no significant difference in the vertical and horizontal directions.

  The resin sheet according to the present invention can be widely used in applications where high mechanical properties are required, even in cases where it is required to form a curved structure into a complex structure.

DESCRIPTION OF SYMBOLS 1 Single layer sheet 2, 3, 17, 69, 91 Laminated sheet 4-6, 36, 38, 47-49, 61-63, 90 Flat sheet 10 Orientation direction 50-52 Extension sheet 64-66 Lattice knitting sheet 32 Die 33 Resin material 34 Roll 35a, 35b Cutting position 37 Flow direction of single layer sheet 39 Rotary blade 68 Polyester sheet 71, 81 Upper mold 72, 82 Lower mold 73, 83 Mold 78, 79 Resin molded product

Claims (11)

  A carbon fiber composite in which carbon fibers having an average fiber length of 0.1 to 10 mm are blended in a thermoplastic resin in a proportion of 2 to 60%, and the carbon fibers are oriented in a proportion of 65 to 95% along one direction. A resin sheet comprising a resin material.   It is comprised from the flat plate which consists of the said carbon fiber composite resin material which has a thickness of 0.05-10 mm per sheet | seat, and the said carbon fiber orientates in the ratio of 65-95% along the one-side direction of the said flat plate. The resin sheet according to claim 1.   The resin sheet according to claim 2, wherein the flat plates are laminated so that the carbon fibers are oriented along different directions between the flat plates in contact with each other.   The resin sheet according to claim 2 or 3, wherein the flat plate is extended so that the carbon fibers are oriented along different directions between flat plates in contact with each other.   The resin sheet according to any one of claims 2 to 4, wherein the flat plate formed in a belt shape is knitted in a lattice shape.   The resin sheet in any one of Claims 1-5 which has a porosity of 0.01 to 5%.   A resin molded product, wherein a thermoplastic film is laminated on the resin sheet according to claim 1.   It is a manufacturing method of the resin molded product which performs the press process which presses the resin sheet in any one of Claims 1-5, Comprising: The porosity of the said resin sheet is 0.01 to 50% by the said press process. A method for producing a resin molded product, characterized in that the value is reduced from a value within the range (porosity B) to a value within the range of 0.01 to 5% (porosity A).   The manufacturing method of the resin molded product of Claim 8 which implements the said press process in the state whose surface temperature of the said resin sheet is 10-100 degreeC higher than melting | fusing point of the said thermoplastic resin.   The manufacturing method of the resin molded product of Claim 9 which implements the heating process which heats the said resin sheet together with the said press process. The manufacturing method of the resin molded product of Claim 9 or 10 which implements the heating process which heats the said resin sheet before the said press process.

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