WO2020246440A1

WO2020246440A1 - Fiber reinforced resin molded body

Info

Publication number: WO2020246440A1
Application number: PCT/JP2020/021663
Authority: WO
Inventors: 田中忠玄; 平石陽一; 中村崇; 中明裕太; 駒井優貴
Original assignee: 倉敷紡績株式会社
Priority date: 2019-06-07
Filing date: 2020-06-01
Publication date: 2020-12-10
Also published as: JPWO2020246440A1; TW202103918A

Abstract

A plurality of resin integrated fiber sheets 30, 31 each comprising a continuous fiber sheet and a thermoplastic resin are stacked on one another, at least two types of the resin integrated fiber sheets are stacked and integrated, including a surface layer and an inner layer, and a resin integrated fiber sheet 30 in at least one surface layer and another resin integrated fiber sheet 31 differ from one another. Unidirectional continuous fibers in which continuous fiber groups are opened and are arranged in parallel in one direction, and cross-linking fibers in a direction interleaved with the unidirectional continuous fibers exist in each continuous fiber sheet, and the cross-linking fibers are preferably adhesively fixed to the continuous fiber sheets by means of thermoplastic resin. In this way, functionality is imparted to at least one surface layer, and the other layers have high strength, thereby providing a fiber reinforced resin molded body which also as a whole has adequate strength for practical use.

Description

Fiber reinforced resin molded body

The present invention relates to a fiber-reinforced resin molded body composed of a laminated body in which resin-integrated fiber sheets of different resins are laminated.

Fiber reinforced composites made of fiber and matrix resin have excellent mechanical properties, such as building materials, laptop housings, IC trays, sports equipment such as shoes and sticks, windmills, automobiles, railroads, ships, aviation, and space. It is widely used in general industrial applications such as. In particular, a fiber-reinforced composite material in which a reinforcing fiber base material sheet having good workability is impregnated with a resin is used in a wide range of applications as a material having both light weight, strength, rigidity and the like. Among them, the continuous fiber sheet has extremely high tensile strength as compared with the discontinuous fiber sheet, and is regarded as useful for members requiring strength such as structural members and outer panels of aviation, space, ships, automobiles, and buildings. As the fiber, the demand for FRP using glass fiber, carbon fiber, and aramid fiber is high, and the demand for carbon fiber is particularly increasing.
As a method for producing a fiber-reinforced composite material, various methods can be applied depending on the state of the product and the required physical properties. A fiber-reinforced composite material can be manufactured by laminating and molding a plurality of intermediate materials (prepregs, semipregs) composed of a resin and a fiber sheet as a matrix resin. The fiber-reinforced composite material can be made by laminating a plurality of sheets using carbon fibers arranged in one direction as a reinforcing fiber base material in one direction, an orthogonal direction, or a different direction with respect to the fiber axis direction, and in each direction. On the other hand, physical properties are controlled.

Fiber reinforced composites are required to have various properties other than improving strength and moldability. In particular, it is possible to improve the surface properties of the fiber-reinforced composite material to improve functions such as flame retardancy, weather resistance, water resistance, chemical resistance, paintability, processability, functionality, and thermal conductivity. As a prior art, there is a proposal of laminating a resin or a film on the surface of a fiber-reinforced composite material (Patent Documents 1 to 4).

WO2017 / 030190 specification JP-A-2018-171787 Japanese Unexamined Patent Publication No. 2012-61780 Japanese Unexamined Patent Publication No. 2011-37150

However, in the prior art, in the case of a thin fiber-reinforced composite material, if the outermost layer is a resin film, there is a problem that the strength is lowered. If the resin used as the structural material is not a matrix resin, there is a problem in strength and the like. Further, in the composite material of the thermosetting resin and the thermoplastic resin, the thermosetting resin and the thermoplastic resin cannot be molded at the same time, and the thermoplastic resin sheet is bonded to the molded plate of the reinforcing fiber of the thermosetting resin. Since it is a process, it is difficult to integrally mold it at the same time, and it is not suitable for processing that requires shapeability.
In order to solve the above-mentioned conventional problems, the present invention provides a fiber-reinforced resin molded product in which at least one surface layer is provided with functionality, the other layer has high strength, and the overall strength is practically sufficient. provide.

The fiber-reinforced resin molded body of the present invention is a fiber-reinforced resin molded body in which a plurality of resin-integrated fiber sheets composed of a continuous fiber sheet and a thermoplastic resin are laminated, and the fiber-reinforced resin molded body is 2 It is characterized in that more than one type of resin-integrated fiber sheet is laminated and integrated, including a surface layer and an inner layer, and the resin-integrated fiber sheet of at least one surface layer is different from the other resin-integrated fiber sheets. To do.

In the present invention, a plurality of resin-integrated fiber sheets composed of a continuous fiber sheet and a thermoplastic resin are laminated, and include a surface layer and an inner layer, and the resin-integrated fiber sheet of at least one surface layer and the other resin are integrated. By being different from the synthetic fiber sheet, at least one surface layer is imparted with functionality, the other layer has high strength, and it is possible to provide a fiber-reinforced resin molded body having practically sufficient strength as a whole. Further, it can be a fiber-reinforced resin molded product that is thin and has strength that can withstand practical use. Further, since the matrix resin is a thermoplastic resin, the molding cycle is fast, the shapeability is good, and efficient integral molding is possible.

FIG. 1 is a schematic perspective view of a resin-integrated carbon fiber sheet according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the resin-integrated carbon fiber sheet in the width direction. FIG. 3 is a schematic process diagram showing a method for producing a resin-integrated carbon fiber sheet according to an embodiment of the present invention. FIG. 4A is a schematic perspective view of two types of resin integrated fiber sheets used in one embodiment of the present invention, and FIG. 4B is a schematic explanatory view of laminating the resin integrated fiber sheets. FIG. 5 is a stress-displacement measurement graph of Example 1 of the present invention. FIG. 6 is a stress-displacement measurement graph of Comparative Example 1. FIG. 7 is a stress-displacement measurement graph of Example 2 of the present invention. FIG. 8 is a stress-displacement measurement graph of Comparative Example 2.

The present invention is a fiber-reinforced resin molded product in which a plurality of resin-integrated fiber sheets composed of a continuous fiber sheet and a thermoplastic resin are laminated. In this fiber-reinforced resin molded body, two or more types of resin-integrated fiber sheets are laminated and integrated, and the resin-integrated fiber sheet of at least one surface layer is different from the other resin-integrated fiber sheets. As a result, functionality such as adhesiveness can be imparted to at least one surface layer. It is preferable that the resin-integrated fiber sheet of both surface layers is different from the resin-integrated fiber sheet of the inner layer. Further, the resin-integrated fiber sheets of both surface layers may be the same or different. As a result, functionality such as adhesiveness can be imparted to both surface layers, and the balance of strength can be improved.

The thickness of the fiber-reinforced resin molded product is preferably 0.1 to 5.0 mm, more preferably 0.25 to 3.0 mm. As a result, a thin and high-strength molded product can be obtained.

Reinforcing fibers are used as the fibers of the fiber-reinforced resin molded product. Reinforcing fibers include carbon fibers, glass fibers, aramid fibers, and other thermoplastic fibers (polyethylene, polypropylene, etc.). However, carbon fiber is preferable because it is intended for thin materials.

The resins include polyamide-based resin, polycarbonate-based resin, polypropylene-based resin, polyester-based resin, polyethylene-based resin, acrylic-based resin, phenoxy resin, polystyrene-based resin, polyimide-based resin, polyetheretherketone (PEEK) -based resin, and It is preferably selected from polyetherketoneketone (PEKK) -based resins, and the resin of the resin-integrated fiber sheet of at least one surface layer and the resin of the other resin-integrated fiber sheet are preferably different.

As an example of the fiber-reinforced resin molded body, two resin-integrated fiber sheets (one on each of the front and back surfaces) made of polyamide (PA) 12 resin and carbon fiber on both surface layers, and phenoxy resin and carbon fiber on the inner layer. Twelve resin-integrated fiber sheets are arranged and laminated and integrated. As a result, the PA12 resin has good adhesiveness to rubber and metal, so that it is convenient to integrate with rubber or metal, and rubber can be attached. It is well known in JP-A-2015-145129 and JP-A-2005-111902 that the adhesiveness between PA12 and rubber is good, and that the adhesiveness between PA12 and metal is good is published in JP-A-2004-346255. It is well known in Japanese Patent Application Laid-Open No. 2003-089773 and JP-A-10-330651. As another example, two resin-integrated fiber sheets (one on each of the front and back surfaces) made of phenoxy resin and carbon fiber on both surface layers, and a resin-integrated fiber sheet 12 made of polycarbonate (PC) resin and carbon fiber on the inner layer. The sheets are arranged and laminated and integrated. As a result, since the phenoxy resin is a resin having high water resistance, the water resistance can be improved.

In the continuous fiber sheet, unidirectional continuous fibers in which continuous fiber groups are opened and arranged in parallel in one direction and crosslinked fibers in a direction intersecting with the unidirectional continuous fibers are present, and the crosslinked fibers are made of a thermoplastic resin. It is preferably bonded and fixed to the continuous fiber sheet. As a result, the strength in the width direction is high, the cleavage property is low, and the handleability is good even if the thickness is thin. The crosslinked fibers are preferably those generated from the continuous fiber group when the continuous fiber group is opened to form unidirectional continuous fibers arranged in parallel in one direction. The crosslinked fibers generated from the continuous fiber group in a series of steps are interlaced or entangled with the continuous fiber sheet, and have low cleavability. The continuous fiber sheet may be a woven fabric.

When the total of the unidirectional continuous fibers and the crosslinked fibers is used as a parameter, the crosslinked fibers are preferably 1 to 25% by mass, more preferably 3 to 20% by mass, and further preferably 5 to 15% by mass. .. When the crosslinked fibers are present in the above proportions, the strength of the continuous fiber sheet in the width direction is high, the fissure is low, and the handleability can be further improved.

The continuous fiber sheet is preferably a semi-preg in which resin powder is adhered to the surface and melted. This semi-preg can be manufactured by a dry method, and the manufacturing efficiency is high. Further, the continuous fiber sheet may be a prepreg impregnated with a resin.

When the resin-integrated fiber sheet is 100% by volume, the fiber is preferably 30 to 70% by volume and the resin is 70 to 30% by volume, more preferably 35 to 65% by volume of the fiber and 65 to 35% by volume of the resin. is there. As a result, the resin component of the resin-integrated fiber sheet can be directly used as the matrix resin component of the molded product. That is, it is possible to eliminate the need to add a new resin when manufacturing the molded product. The mass of the resin-integrated fiber sheet is preferably 10 to 3000 g / m ² , more preferably 20 to 2000 g / m ² , and even more preferably 30 to 1000 g / m ² .

The resin adhered state of the resin-integrated fiber sheet of the present invention is that the resin is melt-solidified and adhered near the surface of the opened fiber sheet, and the resin is not impregnated inside the fiber sheet. It is preferably partially impregnated. In the above state, it is preferable to heat and pressurize a plurality of resin-integrated fiber sheets in a laminated state to form a fiber-reinforced resin molded product.

In the case of carbon fibers, the width of the spread fiber sheet (hereinafter, also referred to as “spread fiber sheet”) is preferably 0.1 to 5.0 mm per 1000 constituent fibers. Specifically, the width of the spread fiber sheet is about 0.1 to 1.5 mm per 1000 constituent fibers in the case of a large tow such as 50K or 60K, and the constituent fibers in the case of a regular tow such as 12K or 15K. It is about 0.5 to 5.0 mm per 1000 pieces. As the number of constituent fibers of the tow per fiber increases, the twist of the fibers increases and it becomes difficult to open the fibers, so that the width of the opening sheet also becomes narrower. As a result, the unopened fiber tow sold by the carbon fiber manufacturer can be expanded to form an easy-to-use spread fiber sheet, which can be supplied to various molded products. The carbon fiber bundle (toe) of the feed yarn is preferably 5,000 to 50,000 / bundle, and 10 to 280 carbon fiber bundles (tow) are preferably supplied. When a plurality of carbon fiber bundles (tow) are supplied and opened in this way to form a single sheet, the space between the carbon fiber bundle (toe) and the carbon fiber bundle (toe) is easily cleaved, but in various directions. When the crosslinked fibers having properties are adhered and fixed to the sheet with a resin, cleavage between the toes can be prevented.

The average length of the crosslinked fibers is preferably 1 mm or more, more preferably 5 mm or more. When the average length of the crosslinked fibers is within the above range, the carbon fiber sheet has high strength in the width direction and is excellent in handleability.

The method for producing a resin-integrated fiber sheet of the present invention includes the following steps. A carbon fiber sheet will be described as a fiber sheet.
A When the carbon fiber filament group is opened by at least one means selected from passing through a plurality of rolls, passing through a fiber opening bar, and air fiber opening and arranging in parallel in one direction, the fiber is opened or opened. Later, the crosslinked fibers are generated from the carbon fiber filament group, or the crosslinked fibers are dropped onto the carbon fiber sheet at the time of opening or after opening, and the average number of the crosslinked fibers is one or more per 10 mm ² of the carbon fiber sheet. When the carbon fiber filament group is opened by passing through a roll or an opening bar, by applying tension to the carbon fiber filament group, crosslinked fibers can be generated from the carbon fiber filament group at the time of opening. The tension of the carbon fiber filament group can be, for example, in the range of 2.5 to 30 N per 15,000 fibers. When air defibration is adopted, it is preferable to generate crosslinked fibers by a roll or a defibration bar after this. When the crosslinked fibers are generated from the carbon fiber filament group, the crosslinked fibers are in a state of being interlaced with the carbon fibers constituting the carbon fiber sheet. Here, crossing includes entanglement. For example, some or all of the crosslinked fibers are present in the carbon fiber sheet and are sterically interlaced with the carbon fibers arranged in one direction.
B Powder resin is applied to the opened carbon fiber sheet.
C The powder resin is heated and melted in a pressure-free (no pressure) state, cooled, and the resin is partially present on at least a part of the surface of the carbon fiber sheet. At this time, the crosslinked fibers are adhered and fixed to the carbon fiber sheet with the resin on the surface.

The following will be explained using drawings. In the drawings below, the same reference numerals indicate the same products. FIG. 1 is a schematic perspective view of the resin-integrated carbon fiber sheet 1 according to the embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the resin-integrated carbon fiber sheet 1 in the width direction. Crosslinked fibers 3 are arranged in various directions on the surface of the opened carbon fiber sheet 2. Further, the resin 4 is melt-solidified and adhered to the vicinity of the surface of the carbon fiber sheet 2, and the resin 4 is not or partially impregnated inside the carbon fiber sheet 2. The resin 4 adheres and fixes the crosslinked fiber 3 to the surface of the carbon fiber sheet 2. As shown in FIG. 2,

crosslinked fibers

3a and 3b are present on the surface of the carbon fiber sheet 2. The crosslinked fibers 3a are all on the surface of the carbon fiber sheet 2. A part of the crosslinked fiber 3b is on the surface of the carbon fiber sheet 2, and a part of the crosslinked fiber 3b is in a state of entering the inside and interlacing with the carbon fiber. The resin 4 adheres and fixes the crosslinked fiber 3 to the surface of the carbon fiber sheet 2. Further, there is a portion to which the resin 4 is attached and a portion 5 to which the resin is not attached. The portion 5 to which the resin does not adhere is a passage through which the air inside the fiber sheet escapes when the resin-integrated carbon fiber sheet 1 is heated and pressed in a laminated state to form a fiber-reinforced resin molded product. Therefore, the resin on the surface is easily impregnated in the entire fiber sheet by pressurization. As a result, the resin 4 becomes a matrix resin of the fiber-reinforced resin molded product.

FIG. 3 is a schematic process diagram showing a method for producing a resin-integrated carbon fiber sheet according to an embodiment of the present invention. The carbon fiber filament group (toe) 8 is pulled out from a large number of supply bobbins 7 and passed between the opening rolls 21a-21j to open the fibers (roll opening step 23). Instead of roll opening, air opening may be used. The spread fiber roll may be fixed or rotated, or may vibrate in the width direction.
After the fiber-spreading step, the opened tow is nipated between the nip rolls 9a and 9b, passed between a plurality of bridge rolls 12a-12b installed between the nip rolls 9a and 9b, and the tension of the toe is applied per 15,000, for example (1). Cross-linked fibers are generated by applying in the range of 2.5 to 30 N (corresponding to the carbon fiber filament group supplied from each supply bobbin) (cross-linked fiber generation step 24). The bridge roll may rotate or oscillate in the width direction. The bridge roll has a satin finish, an uneven surface, a mirror surface, and a plurality of rolls, and the carbon fiber filament group is bent, fixed, rotated, vibrated, or a combination thereof to generate crosslinked fibers. 13a-13g is a guide roll.
After that, the dry powder resin 15 is sprinkled on the surface of the spread sheet from the powder supply hopper 14, supplied into the heating device 16 in a pressure-free state and heated to melt the dry powder resin 15, and between the guide rolls 13f-13g. Cooling. After that, the dry powder resin 18 is sprinkled on the back surface of the spread fiber sheet from the powder supply hopper 17, and the dry powder resin 18 is supplied into the heating device 19 in a pressure-free state and heated to melt the dry powder resin 18, cool it, and wind up the roll 20. (Powder resin applying step 25). The dry powder resins 15 and 18 are, for example, phenoxy resins (glass transition point 180 ° C.), the temperatures in the

heating devices

16 and 19 are, for example, + 20 to 60 ° C. of the melting point or glass transition point of the resin, and the residence time is, for example, 4 each. Let it be seconds. As a result, the carbon fiber spread sheet has high strength in the width direction, and the constituent carbon fibers do not fall apart and can be handled as a sheet.

Powder resin can be applied by powder coating method, electrostatic coating method, spraying method, fluid immersion method, etc. A powder coating method in which the powder resin is dropped on the surface of the carbon fiber sheet is preferable. For example, a dry powder-like powder resin is sprinkled on the opened carbon fiber sheet.

FIG. 4A is a schematic perspective view of two types of resin integrated fiber sheets used in one embodiment of the present invention, and FIG. 4B is a schematic explanatory view of laminating the resin integrated fiber sheets. As shown in FIG. 4A, the resin integrated fiber sheet 30 is composed of carbon fibers 32 and resin 33 arranged in one direction, and is arranged on both surface layers. The resin-integrated fiber sheet 31 is composed of carbon fibers 32 and resin 34 arranged in one direction, and is arranged in the inner layer. The crosslinked fibers shown in FIGS. 1 and 2 are present in the resin-integrated

fiber sheets

30 and 31, but are omitted in the drawing. As shown in FIG. 4B, a plurality of resin-integrated fiber sheets 31 are used as inner layers, resin-integrated fiber sheets 30 are arranged on both surfaces thereof, and the whole is pressurized and heated to be laminated and integrated to form a fiber-reinforced resin molded product. Let it be 35. The pressing force for laminating and integrating is preferably 0.2 to 10 MPa, the temperature is preferably + 20 to 60 ° C. of the melting point or flow start temperature of the resin, and the time is preferably 2 to 15 minutes.

A preferred example of the present invention can be summarized as follows.
(1) Fiber-reinforced resin molded product The fiber-reinforced resin molded product has a laminated structure of two or more layers. The directionality of the fibers does not matter, but a unidirectional sheet is preferable in consideration of thinness. It is preferable to laminate a sheet with added functionality on at least one surface layer side. Considering warpage after molding, a layer having the same front and back surfaces is preferable. That is, the fiber-reinforced resin molded body is a front surface layer (1 to 2 layers) / inner layer (N layer) / back surface layer (1 to 2 layers), and the number N of inner layers is preferably 1 to 100, and the total number of layers is 3 to 102 is preferable.
(2) Molding As a molding method, a general compression molding method such as press molding or vacuum forming is used. As a result, it is integrally molded. It is meaningless to have the surface layer and the inner layer as separate processes.
(3) Others It is preferable to impart functionality to at least one surface layer. The functionality includes adhesiveness, printability, weather resistance, water resistance, chemical resistance, paintability, processability, functionality, thermal conductivity, flame retardancy, surface smoothness and the like. It is also possible to change the fiber volume fraction (Vf) of the resin-integrated fiber sheet to be laminated. In particular, imparting adhesiveness to the surface layer of the fiber-reinforced resin molded product is useful for integrating with at least one selected from metal, resin and rubber.

Hereinafter, the present invention will be specifically described with reference to Examples. The present invention is not limited to the following examples.
(Example 1)
(1) Carbon fiber unopened fiber tow The carbon fiber unopened fiber tow was manufactured by Mitsubishi Chemical Corporation, product number: PYROFILE TR 50S15L, shape: regular tow filament 15K (15,000 fibers,), and a single fiber diameter of 7 μm was used. An epoxy compound is attached to the carbon fiber of the unopened carbon fiber tow as a sizing agent.
(2) Means for opening the unopened fiber tow The fibers were opened using the opening means shown in FIG. In the fiber opening step, the tension of the carbon fiber filament group (toe) was set to 15 N per 15,000 fibers. In this way, an spread sheet having a carbon fiber filament composition of 50 K, a spread width of 500 mm, and a thickness of 0.08 mm was obtained. The crosslinked fiber was 3.3% by mass. The basis weight was 80 g / m ² .
(3-1) Semi-preg 1
A phenoxy resin (manufactured by Gabriel, glass transition point 180 ° C.) was used as the dry powder resin. The average particle size of the dry powder resin was 80 μm. An average of 26.2 g of this resin was applied to 1 m ^{2 of} carbon fibers on one side and 52.4 g on both sides. The temperatures in the

heating devices

16 and 19 were 220 ° C., and the residence time was 4 seconds each. Mass 132.4g / m ² (resin: 52.4g / m ^2, the fibers: 80g / m ²⁾ was.
(3-2) Semi-preg 2
PA12 resin (manufactured by Daicel Evonik, melting point 176 ° C.) was used as the dry powder resin. The average particle size of the dry powder resin was 80 μm. An average of 24.0 g of this resin was applied to 1 m ^{2 of} carbon fibers on one side and 48.0 g on both sides. The temperature in the

heating devices

16 and 19 was 200 ° C., and the residence time was 4 seconds each. The mass was 128.0 g / m ² (resin: 48 g / m ² , fiber: 80 g / m ² ).
(4) Molding of molded body One semi-preg 2 is installed on the front and back surfaces, 10 semi-pregs 1 are arranged in the inner layer, the base fiber direction is one direction, the base size is 250 mm in length and 250 mm in width, and a press is used. Molding was performed at 260 ° C. and 3 MPa for 5 minutes.

(Comparative Example 1)
The same experiment as in Example 1 was carried out except that the semi-preg 2 of Example 1 was used for all layers as the resin-integrated fiber sheet (semi-preg).

A sample was cut out from the molded products of Example 1 and Comparative Example 1 to a length of 80 mm (designated direction) and a width of 15 mm, and allowed to stand at a temperature of 23 ° C. and a relative humidity of 50% for 48 hours or more. Six samples were taken for each of 1 product of Example and 1 product of Comparative Example. The sizes of the obtained samples are summarized in Table 1.

Next, the prepared sample was subjected to a three-point bending test in accordance with JIS K7074. The conditions were as follows.
・ Jig: Indenter = R5, fulcrum = R2
・ Lower support interval: 60 mm
・ Test speed: 5mm / min
・ Number of tests: 6 times

The results of the 3-point bending test are shown in Table 2 and FIGS. 5 to 6. FIG. 5 is a stress-displacement measurement graph of Example 1 of the present invention, and FIG. 6 is a stress-displacement measurement graph of Comparative Example 1. The numerical values in FIGS. 5 to 6 indicate the measurement order.

As is clear from Table 2, since the matrix resin of both surface layers of Example 1 is PA12 resin, it is imparted with the functionality of having high adhesive strength to rubber and metal, and is practically sufficient as a whole. It had strength.

(Example 2)
(1) Carbon fiber unopened fiber tow The carbon fiber unopened fiber tow was manufactured by Mitsubishi Chemical Corporation, product number: PYROFILE TR 50S15L, shape: regular tow filament 15K (15,000 fibers,), and a single fiber diameter of 7 μm was used. An epoxy compound is attached to the carbon fibers of the unopened carbon fiber tow as a sizing agent.
(2) Means for opening the unopened fiber tow The fibers were opened using the opening means shown in FIG. In the fiber opening step, the tension of the carbon fiber filament group (toe) was set to 15 N per 15,000 fibers. In this way, an spread sheet having a carbon fiber filament composition of 50 K, a spread width of 500 mm, and a thickness of 0.08 mm was obtained. The crosslinked fiber was 3.3% by mass. The basis weight was 80 g / m ² .
(3-1) Semi-preg 3
A polycarbonate resin (manufactured by Teijin Limited, melting point 240 ° C. or less) was used as the dry powder resin. The average particle size of the dry powder resin was 180 μm or less. An average of 26.4 g of this resin was applied to 1 m ^{2 of} carbon fibers on one side and 53 g on both sides. The temperatures in the

heating devices

16 and 19 were 260 ° C., and the residence time was 4 seconds each. The mass was 133 g / m ² (resin: 53 g / m ² , fiber: 80 g / m ² ).
(3-2) Semi-preg 4
A phenoxy resin (manufactured by Gabriel, glass transition point 180 ° C.) was used as the dry powder resin. The average particle size of the dry powder resin was 80 μm. An average of 26.2 g of this resin was applied to 1 m ^{2 of} carbon fibers on one side and 52.4 g on both sides. The temperatures in the

heating devices

16 and 19 were 220 ° C., and the residence time was 4 seconds each. Mass 132.4g / m ² (resin: 52.4g / m ^2, the fibers: 80g / m ²⁾ was.
(4) Molding of molded body One semi-preg 4 is installed on the front and back surfaces, 10 semi-pregs 3 are arranged in the inner layer, the base fiber direction is one direction, the base size is 250 mm in length and 250 mm in width, and the press Molding was performed at 300 ° C. and 3 MPa for 5 minutes.

(Comparative Example 2)
The same experiment as in Example 2 was carried out except that the semi-preg 3 of Example 2 was used for all layers as the resin-integrated fiber sheet (semi-preg).

A sample was cut out from the molded products of Example 2 and Comparative Example 2 to a length of 80 mm (designated direction) and a width of 15 mm, and allowed to stand at a temperature of 23 ° C. and a relative humidity of 50% for 48 hours or more. Six samples were taken for each of the two Examples and the two Comparative Examples. The sizes of the obtained samples are summarized in Table 3.

The results of the 3-point bending test are shown in Table 4 and FIGS. 7 to 8. FIG. 7 is a stress-displacement measurement graph of Example 2 of the present invention, and FIG. 8 is a stress-displacement measurement graph of Comparative Example 2. The numerical values in FIGS. 7 to 8 indicate the measurement order.

As is clear from Table 4, since the matrix resin of both surface layers of Example 2 is a phenoxy resin, it is possible to impart a function having excellent moisture resistance, and further, the flexural modulus and bending from Example 2 and Comparative Example 2 The strength was the same, and it had a practically sufficient strength.

The fiber-reinforced resin molded product of the present invention is widely applied to building materials, laptop housings, IC trays, sporting goods such as shoes and sticks, and general industrial applications such as windmills, automobiles, railways, ships, aerospace, and the like. it can.

1 Resin-integrated carbon fiber sheet 2

Carbon fiber sheet

3,3a, 3b Cross-linked fiber 4 Resin 5 Part where resin is not attached 6 Fiber opening device 7 Supply bobbin 8 Carbon fiber filament group (carbon fiber unopened fiber toe)
9a, 9b Nip roll 12a-12b Bridge roll 13a-

13g Guide roll

14,17

Powder supply hopper

15, 18

Dry powder resin

16, 19 Heating device 20 Winding roll 21a-21j Spreading roll 23 Roll opening process 24 Cross-linked fiber generation Step 25 Powder

resin applying step

30, 31 Resin integrated fiber sheet 32

Carbon fiber

33, 34 Resin 35 Fiber reinforced resin molded product

Claims

A fiber-reinforced resin molded product in which a plurality of resin-integrated fiber sheets composed of a continuous fiber sheet and a thermoplastic resin are laminated.
The fiber-reinforced resin molded body is formed by laminating and integrating two or more types of resin-integrated fiber sheets, and includes a surface layer and an inner layer.
A fiber-reinforced resin molded product characterized in that the resin-integrated fiber sheet of at least one surface layer is different from the other resin-integrated fiber sheet.
The fiber-reinforced resin molded body according to claim 1, which is different from the resin-integrated fiber sheet of both surface layers and the resin-integrated fiber sheet of the inner layer.
The fiber-reinforced resin molded product according to claim 1 or 2, wherein the thickness of the fiber-reinforced resin molded product is 0.1 to 5.0 mm.
The resins include polyamide-based resin, polycarbonate-based resin, polypropylene-based resin, polyester-based resin, polyethylene-based resin, acrylic-based resin, phenoxy resin, polystyrene-based resin, polyimide-based resin, polyetheretherketone-based resin, and polyetherketone. The fiber-reinforced resin according to any one of claims 1 to 3, wherein the resin of the resin-integrated fiber sheet of at least one surface layer selected from the ketone (PEKK) -based resin and the resin of the other resin-integrated fiber sheet are different. Molded body.
The continuous fiber sheet includes unidirectional continuous fibers in which continuous fiber groups are opened and arranged in parallel in one direction, and crosslinked fibers in a direction intersecting the unidirectional continuous fibers. The fiber-reinforced resin molded body according to any one of claims 1 to 4, which is adhered and fixed to the continuous fiber sheet with a thermoplastic resin.
The fiber-reinforced resin molded product according to claim 5, wherein the crosslinked fibers are 1 to 25% by mass when the total of the unidirectional continuous fibers and the crosslinked fibers is used as a population.
The fiber-reinforced resin molded product according to any one of claims 1 to 6, wherein the continuous fiber sheet is a woven fabric.
The fiber-reinforced resin molded product according to any one of claims 1 to 6, wherein the continuous fiber sheet is a semi-preg in which thermoplastic resin powder is adhered to the surface and melted.
The fiber-reinforced resin molded product according to any one of claims 1 to 7, wherein the continuous fiber sheet is a prepreg impregnated with a resin.
The fiber-reinforced resin molded product according to any one of claims 1 to 9, wherein the resin-integrated fiber sheet is 100% by volume, the fiber is 30 to 70% by volume, and the resin is 70 to 30% by volume.
The fiber-reinforced resin molded product according to any one of claims 1 to 10, wherein the resin is a resin that serves as a matrix resin for the fiber-reinforced resin molded product.
The fiber-reinforced resin molded product according to any one of claims 1 to 11, wherein the fiber-reinforced resin molded product is a fiber-reinforced resin molded product for integrating with at least one selected from metal, resin, and rubber.