JP2008279753A - Manufacturing method of fiber-reinforced plastics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of fiber-reinforced plastics with advantages such as successful fluidity/molding follow-up properties of complicated shape, and excellent mechanical characteristics, low variability and dimensional stability, when the fiber-reinforced plastic products are manufactured. <P>SOLUTION: The fiber-reinforced plastic products are molded through the sequence of at least the following processes (1) to (3): (1) a lamination process to obtain a laminate by laminating a plurality of prepreg base materials in the way that an area where only the deeply cut prepreg base material with the reinforcing fiber split to the length of 10 to 100 mm, is formed on at least, a part of the laminate, (2) a molding process to arrange the above area in the double contour part of the molding die and mold the laminate with the above area stretched along the double contour part, and (3) a process to unload the fiber-reinforced plastic products from the molding die. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a fiber reinforced plastic that has good fluidity and molding followability, and exhibits excellent mechanical properties, its low variation, and excellent dimensional stability when made into a fiber reinforced plastic. Such fiber reinforced plastics are particularly preferably used for structural members such as transport equipment such as automobiles and sports equipment such as bicycles.

  Fiber reinforced plastic consisting of reinforced fiber and matrix resin is attracting attention in industrial applications because it has high specific properties, high specific modulus, excellent mechanical properties, weather resistance, chemical resistance, etc. The demand is increasing year by year.

  As a method for molding fiber reinforced plastic, a semi-cured intermediate base material impregnated with a thermosetting resin is laminated on a continuous reinforcing fiber called a prepreg base material, and heat is applied by heating and pressurizing with a high-temperature and high-pressure kettle. Autoclave molding in which a curable resin is cured and a fiber-reinforced plastic is molded is most commonly performed. In recent years, for the purpose of improving production efficiency, RTM (resin transfer molding) molding in which a continuous fiber base previously shaped into a member shape is impregnated with a thermosetting resin and cured has been performed. The fiber reinforced plastics obtained by these molding methods have excellent mechanical properties because they are continuous fibers. Further, since the continuous fibers are regularly arranged, it is possible to design the mechanical properties required by the arrangement of the base material, and the variation in the mechanical properties is small. However, there is a problem that it is difficult to form a three-dimensional shape because it is a continuous fiber.

  This problem was more serious especially in the case of complex three-dimensional shapes. If you imagine a sheet that is difficult to cause shear deformation in a plane, such as paper, in a complicated three-dimensional shape, it is easy to understand. However, when such a continuous fiber substrate is shaped, the surface of the shape cannot be covered. However, since wrinkles are generated at the place where the base material is left, high-quality shaping is difficult. Even if it is a continuous fiber base material, if it can be sheared in-plane like a woven base material, it is much easier to shape than paper etc., but if the shape becomes complicated, fiber tension and There was a problem that wrinkles would occur.

For example, bundled discontinuous fibers such as BMC (bulk molding compound) (for example, Patent Document 1), SMC (Sheet Molding Compound) and stampable sheet (for example, Patent Document 2) are made of thermosetting resin or thermoplastic resin. Although it is known that if the sheet base material mixed and dispersed with the resin is used, the three-dimensional shape having the above-mentioned double contour portion can be formed and followed, but the mechanical properties are low, so it cannot be applied to a structural member. was there.
JP-A-8-118379 JP-A-9-267344

  In view of the background of such prior art, the present invention has excellent fluidity, molding followability of complicated shapes, and excellent mechanical properties, low variability, and excellent dimensional stability when used as a fiber reinforced plastic. Is to provide a fiber-reinforced plastic and a method for producing the same.

The present invention employs the following means in order to solve such problems. That is,
(I) A method for producing a fiber reinforced plastic, wherein a laminate of a prepreg base material composed of reinforced fibers aligned in one direction and a thermosetting resin is hot-press molded to obtain a fiber reinforced plastic having a double contour portion. And, as the prepreg base material, using a cut prepreg base material in which at least a part of the reinforcing fibers is divided into a length of 10 to 100 mm by a plurality of incisions in a direction crossing the reinforcing fibers, at least the following ( A method for producing a fiber reinforced plastic, comprising sequentially molding the fiber reinforced plastic through steps 1) to (3).
(1) When a laminated body is obtained by laminating a plurality of prepreg base materials including the cut prepreg base material, at least a part of the laminated body is divided into 10 to 100 mm in length by reinforcing the cut. Lamination process (2) to obtain a flat laminate, placing the laminate on a mold and softening by heating so that a region where only the cut prepreg base material is laminated is formed. When the laminate is pressed against the mold and cured to form a fiber reinforced plastic, the region is disposed in the double contour portion of the mold, and the region is stretched and molded along the double contour portion. Molding step (3) A demolding step of taking out the fiber reinforced plastic from the mold.

(II) A method for producing a fiber reinforced plastic, in which a laminate of a prepreg base material composed of reinforced fibers and a thermoplastic resin aligned in one direction is cold-press formed into a fiber reinforced plastic having a double contour portion. Then, as the prepreg base material, at least the following (4), using a notched prepreg base material in which at least a part of the reinforcing fibers is divided into a length of 10 to 100 mm by a plurality of incisions in a direction crossing the reinforcing fibers. ) To (6), a method for producing a fiber reinforced plastic, wherein the fiber reinforced plastic is molded sequentially.
(4) When a laminated body is obtained by laminating a plurality of prepreg base materials including the cut prepreg base material, at least a part of the laminated body is cut into lengths of 10 to 100 mm by the cutting to provide reinforcing fibers. Lamination process (5) to obtain a flat laminate by heating so as to form a region in which only the cut prepreg base material is laminated. The laminate is heated and softened at a lower temperature than the laminate. When the laminate is placed on a mold, and the laminate is pressed against the mold and solidified to form a fiber reinforced plastic, the region is placed in the double contour portion of the mold, and the region is expanded. (6) Demolding step of taking out the fiber reinforced plastic from the mold.

  (III) All of the reinforcing fibers constituting the cut prepreg base material are cut by the cut, and the fiber length L cut by the cut is in the range of 10 to 100 mm, (I) or The manufacturing method of the fiber reinforced plastic as described in (II).

  (IV) The incision of the notched prepreg base material is linear, and the length W of the incision is 2 to 100 mm, and is intermittently and periodically disposed over the entire surface. III) The method for producing a fiber-reinforced plastic according to any one of the above.

  (V) The notch prepreg base material is continuously adjacent to two or more layers, and an arbitrary notch geometric center on one notch prepreg base material for any two adjacent layers among the two or more layers. And the other cut prepreg substrate, the fiber-reinforced plastic production method according to any one of (I) to (IV), wherein the layers are laminated so as to be separated from the geometric center of any cut by 5 mm or more.

  (VI) The manufacturing method of the fiber reinforced plastics in any one of Claims (I)-(V) in which the said notch inclines from the fiber orthogonal direction.

  (VII) The method for producing a fiber-reinforced plastic according to any one of (I) to (V), wherein an absolute value of an angle Θ formed by the cut with the reinforcing fiber is in the range of 2 to 25 °.

  (VIII) The method for producing a fiber-reinforced plastic according to any one of (I) to (VII), wherein the laminate is composed only of the cut prepreg base material.

  (IX) The mold is a single-sided mold, the laminated body is disposed on the single-sided mold, the stretchable film is sealed on the laminated body, and the sealed space is formed. The method for producing a fiber-reinforced plastic according to any one of (I) to (VIII), wherein the laminate is pressed against the single-sided mold by a pressure difference from outside air.

  (X) The mold is composed of two or more molds, and when the laminate is pressed against the mold by clamping, continuous fibers are arranged in a region where the laminate first contacts both of the two molds. A method for producing a fiber-reinforced plastic according to any one of (I) to (IX).

  (XI) After the laminating step, prior to the molding step, the laminated body is pre-shaped into a substantially shaped fiber-reinforced plastic after molding, and then the laminated body is placed on a mold (I) to (X) The manufacturing method of the fiber reinforced plastic in any one of.

  (XII) The method for producing a fiber-reinforced plastic according to (XI), wherein the laminate is preshaped into a single contour shape.

  (XIII) In the concavo-convex portion of the fiber reinforced plastic, the layer in which the reinforced fibers are oriented at an angle of ± 10 ° or less from the direction in which the shape change of the concavo-convex portion is the smallest is thicker than the other layers. (XII) The manufacturing method of the fiber reinforced plastic in any one of.

  According to the present invention, when it has good fluidity and molding followability of a complicated shape, and it is a fiber reinforced plastic, it exhibits excellent mechanical properties, its low variation, and excellent dimensional stability. Plastic can be obtained.

  The present inventors have good fluidity, molding conformability of complex shapes, and when made into fiber reinforced plastic, exhibit excellent mechanical properties, its low variation, and excellent dimensional stability, fiber reinforced About the manufacturing method of plastics, we studied diligently, using a cut prepreg base material in which a specific cut pattern was inserted into a specific base material called a prepreg base material composed of carbon fibers and a matrix resin aligned in one direction, In the laminated body in which the cut prepreg base material is laminated in a flat plate shape, a region composed only of reinforcing fibers having a fiber length within a specific range is cut by pressing and stretched to a double contour portion of a mold, and fiber reinforced plastic is obtained. It was clarified that this problem can be solved at once by molding.

  In addition, the manufacturing method of this invention makes object the fiber reinforced plastic which has a three-dimensional shape and has a double contour part. A part of the fiber reinforced plastic may have ribs or bosses. In the present invention, the “fiber reinforced plastic having a double contour portion” is a point on the quadratic curved surface when the surface of the fiber reinforced plastic is taken out as a quadric curved surface. Of the intersection lines of the plane and the quadric surface, a point where the intersection line passing through the point does not become a straight line belongs to the double contour portion even if the plane is referred to, and at least a part of the double contour portion is included. Refers to fiber reinforced plastic. Specifically, a saddle shape, a hemispherical shape, a flat plate having an uneven portion, and the like are applicable, but a flat plate without an uneven portion, a conical shape, and a cylindrical shape are not applicable. In the present specification, unless otherwise specified, in the term including fibers or fibers (for example, “fiber direction”, etc.), the fibers represent reinforcing fibers. In the present specification, the continuous fiber refers to a reinforcing fiber having a fiber length of 100 mm or more. The prepreg base material used in the present invention is a state in which the resin sheet is not completely impregnated between the fibers, in addition to the reinforcing fiber aligned in one direction and the base material in which the reinforcing fiber base material is completely impregnated with resin. And a resin semi-impregnated base material (semi-preg: hereinafter also referred to as semi-impregnated prepreg).

  The cut prepreg base material used in the present invention is composed of a reinforcing fiber and a matrix resin that are aligned in one direction, and at least a part of the reinforcing fibers is cut in a direction crossing the reinforcing fiber by 10 to 100 mm. The one that is divided into the length of. The area | region where the reinforcing fiber is divided | segmented into the length of 10-100 mm on the cutting prepreg base material respond | corresponds to the area | region which a base material can expand | extend at the time of shaping | molding. Therefore, when molding a fiber reinforced plastic having a complicated shape, the laminated body in the region corresponding to the concavo-convex portion is laminated in a region where the reinforcing fibers are divided into lengths of 10 to 100 mm by cutting on the cut prepreg base material. It is essential that

  Since the reinforced fibers are aligned in one direction in the cut prepreg base material used in the present invention, it is possible to design a molded body having arbitrary mechanical properties by controlling the orientation in the fiber direction. In addition, by dividing at least a part of the fibers into a length of 100 mm or less by a plurality of cuts in the direction crossing the fibers, the fibers can flow at the time of molding, particularly in the longitudinal direction of the fibers. Excellent shape conformability. When there is no notch, that is, when only continuous fibers are used, a complicated shape cannot be formed because they do not flow in the fiber longitudinal direction. On the other hand, when the fiber length is less than 10 mm, the fluidity is further improved. However, even if other requirements are satisfied, the high mechanical properties necessary for the structural material cannot be obtained. Considering the relationship between fluidity and mechanical properties, the fiber length needs to be 10 to 100 mm, and more preferably within the range of 20 to 60 mm.

  FIG. 5 shows an example of the flow mechanism of the cut prepreg base material. As shown in FIG. 5 a), when molding is performed by applying pressure 13 from above the laminate 12 in which the 90 ° prepreg base material is sandwiched between the 90 ° prepreg base material, as shown in FIG. The resin forms a flow 14 in the direction of 90 °, and the opening 15 of the end of the reinforcing fiber occurs according to the flow. That is, the longitudinal direction of the fiber is not provided until the prepreg base material made of fibers aligned in one direction is cut, and the cut prepreg base material in which at least some reinforcing fibers are 10 to 100 mm in length is laminated. It is possible to flow into a complex shape, resulting in molding conformability of complex shapes.

  Thus, since the flow of the resin is the driving source, the flow of the fiber is preferably an appropriate Vf (fiber volume content). That is, Vf is preferably 65% or less because sufficient fluidity can be obtained. Moreover, although fluidity | liquidity improves, so that Vf is low, when Vf is less than 45%, since there exists a possibility that a high mechanical characteristic required for a structural material may not be acquired, it is preferable that Vf is 45% or more. Considering the relationship between fluidity and mechanical properties, it is more preferably in the range of 55-60%.

In the present invention, when the matrix resin of the cut prepreg is a thermosetting resin, it is necessary to sequentially perform at least the following steps (1) to (3) when molding the fiber reinforced plastic.
(1) When a laminated body is obtained by laminating a plurality of prepreg base materials including a cut prepreg base material, at least a part of the laminated body is cut with a reinforcing fiber divided into lengths of 10 to 100 mm by cutting. Lamination is performed so that a region where only the prepreg base material is laminated is formed, and a laminating step for obtaining a flat laminate (2) The laminate is placed on a mold and softened by heating. (3) Molding step in which the region is arranged in the double contour part of the molding die, and the region is stretched and molded along the double contour part when being cured by pressing against the molding die Demolding process to take out fiber reinforced plastic from

  For example, as shown in FIG. 1c), the following steps are sequentially performed in manufacturing a fiber reinforced plastic having a hemispherical double contour portion on a flat plate.

  First, a plurality of prepreg base materials including at least a cut prepreg base material are laminated to form a flat laminate. Laminate prepreg base materials one by one along the mold and shape the laminate, or form the final shape of fiber-reinforced plastic after molding (simple shape of the resulting fiber-reinforced plastic) It is also possible to create a laminated body while shaping one by one along the shape of the shape, which has a reduced number of irregularities and a shape with less undulations). According to the invention, it is possible to form the laminate by simply laminating the prepreg base material at a stretch, and it is possible to produce a laminate at a low cost. Further, as shown in FIG. 4, it is essential that at least a part of the laminated body forms a region 37 in which only the cut prepreg base material in which the fibers are cut into a length of 10 to 100 mm by the cut is laminated. And That is, in the region 37, only the cut prepreg base material, which is substantially made only of fibers of 10 to 100 mm, is laminated in the thickness direction of the laminated body. Here, “consisting essentially of fibers of 10 to 100 mm” means that 95% or more of the number of reinforcing fibers contained in the region is divided into 10 to 100 mm. Hereinafter, this region is referred to as a discontinuous portion of the laminate.

  When the fiber reinforced plastic having a complicated shape is molded, the region of the laminated body corresponding to the complex shape is a discontinuous portion, so that it can be easily stretched at the time of molding and can follow the complex shape. 4A) and 4B show examples in which a discontinuous portion is provided in a part of each laminate, and the upper drawing shows a plan view and the lower drawing shows a cross-sectional view taken along the line AA. FIG. 4a) shows an example in which five layers of cut prepreg base material 10a cut into the entire surface are laminated and a prepreg base material 11 made of continuous fibers smaller than the cut prepreg base material 10a is laminated on the surface of one layer. Show. The area | region 37 which is not covered with the prepreg base material 11 which consists of continuous fibers corresponds to a discontinuous part. In addition, as a prepreg base material which consists of continuous fibers, the prepreg base material which aligned the continuous fiber in one direction, the prepreg base material of a textile fabric, etc. can be considered. FIG. 4b) is a laminate 12 in which five layers of cut prepreg base material 10b, in which a part of the cut is made, are laminated, and all of the laminated cut prepreg base materials 10b are at the left end as shown in the upper view of FIG. 4b). An example in which a cut is made only in the area is shown. A region 37 in which the regions where the cuts of the respective cut prepreg base materials 10b are cut overlap each other corresponds to the discontinuous portion.

  In forming a fiber reinforced plastic having a double contour part, when forming using a continuous fiber base material, a flat cut pattern in which the surface shape of the fiber reinforced plastic is developed is created, and continuous cut by the cut pattern. It is necessary to shape the fiber base material along the mold and repeat it for the number of layers to produce a laminate. On the other hand, in the case of molding using the cut prepreg base material according to the present invention, the discontinuous portion extends and follows a complicated shape, so that it is not necessary to form a complicated cut pattern. Because it is not necessary to form it in line with the shape of the fiber reinforced plastic) (that is, it may be shaped to the approximate shape of the fiber reinforced plastic after molding), Therefore, fiber-reinforced plastic can be manufactured with extremely high efficiency.

  Next, hot press molding is performed in which the mold or both the mold and the laminate are heated, the laminate is placed on the mold, the laminate is heated and softened, and the laminate is pressed against the mold and cured. To form fiber reinforced plastic. Hot press molding in the present invention is not only compression molding that mechanically presses with a heated double-sided mold, but also presses the heated single-sided mold with a bag film or the like, or conforms to the shape while pressing with a heated roller or the like. Includes hot drape molding. As shown in FIG. 1b), it is essential to dispose the discontinuous part on the double contour part of the mold, and to stretch the discontinuous part and form the laminate along the double contour part. As the mold, for example, a single-sided mold is used and sealed with a film and evacuated, and the laminate may be pressed against the mold with a pressure difference from atmospheric pressure, a double-sided mold consisting of an upper mold and a lower mold, or a more complicated mold You may press-mold using the split type | mold which consists of 3 or more type | molds corresponding to a shape.

  Finally, the fiber reinforced plastic is taken out from the mold. After the thermosetting resin has been cured, or after being cured to such an extent that it can be removed, the fiber reinforced plastic is taken out of the mold. After taking out the fiber reinforced plastic, it may be put in another oven and post-cured.

As another embodiment of the present invention, when the matrix resin of the cut prepreg base material is a thermoplastic resin, at least the following steps (4) to (6) are sequentially performed when molding the fiber reinforced plastic. It is necessary to go through.
(4) When a laminated body is obtained by laminating a plurality of prepreg base materials including a cut prepreg base material, at least a part of the laminated body is cut with a reinforcing fiber cut into a length of 10 to 100 mm by cutting. Lamination process for obtaining a flat laminate by stacking so that a region where only the prepreg base material is laminated is formed (5) The laminate is heated and softened, and placed on a mold lower in temperature than the laminate. When the laminated body is placed and the laminated body is pressed against a mold and solidified to form a fiber reinforced plastic, the area is arranged in the double contour part of the mold, and the area is stretched to follow the double contour part. Molding step for molding (6) Demolding step of taking out the fiber reinforced plastic from the mold.

  First, a plurality of prepreg base materials including at least a cut prepreg base material are stacked to form a laminate in a flat plate shape. Similar to the case where a thermosetting resin is used as the matrix resin, a laminate having at least a discontinuous portion is produced. When the prepreg is laminated, since the thermoplastic resin as the matrix resin has no tack, the prepreg may be simply laminated or may be heated and fused to integrate the layers. Produces fiber-reinforced plastic with extremely high efficiency due to the advantage of not requiring complicated cut patterns, the advantage of not having to shape the fiber-reinforced plastic completely after molding, and the advantage of being able to be laminated in a flat plate at once. it can.

  Next, the laminate is heated with an IR heater or an oven near or above the melting point of the thermoplastic resin as the matrix resin (however, when heating to a temperature higher than the melting point, the time for exposure to high temperature) ). Place the laminate on a mold that is softened and controlled at room temperature or at a temperature lower than the laminate, press the laminate against the mold, and cool and solidify the laminate. To do. At this time, as shown in FIG. 1b), it is essential to dispose the discontinuous portion on the double contour portion of the mold, and to form the discontinuous portion along the laminate along the double contour portion. . Various molds can be considered as the mold. For example, a single-sided mold may be sealed with a film and evacuated, and the laminate may be pressed against the mold with a pressure difference from atmospheric pressure, but it is preferable to use a double-sided mold. By performing cold pressing with a double-sided mold, heat can be quickly taken from the laminate, and fiber-reinforced plastic can be produced with high efficiency.

  Finally, the fiber reinforced plastic is taken out from the mold. You may add processes, such as annealing, to the obtained fiber reinforced plastic. In general, molding using a thermoplastic resin has an advantage that the molding cycle time is faster than that using a thermosetting resin, and demolding is easy.

  Thus, according to the present invention, even if the shape of the fiber reinforced plastic is a complicated shape, whether it is a thermosetting resin or a thermoplastic resin, a fiber reinforced plastic having high mechanical properties can be obtained. It can be easily manufactured.

  The fiber reinforced plastic thus obtained does not stretch during molding unlike a continuous fiber base material, so that the laminate is firmly pressed against the molding die to obtain a high-quality surface with a sufficiently transferred mold surface. be able to. In addition, since the laminate may be prepared smaller than the fiber reinforced plastic that is the final shape, the bulky laminate cannot be stored in the mold and burrs, wrinkles, and fiber biting between the molds occur. Few. Moreover, a trimless fiber-reinforced plastic can be obtained by using a matched die. As a feature of the fiber reinforced plastic, the fiber length Lc of all the reinforced fibers included in at least a part of the fiber reinforced plastic (particularly, the double contour portion) is in the range of 10 to 100 mm.

  More preferably, all of the reinforcing fibers constituting the cut prepreg base material are cut by the cut, and the fiber length L cut by the cut is in the range of 10 to 100 mm. By making all the fiber lengths L of the cut prepreg base material 100 mm or less, it is possible to manufacture a cut prepreg base material and a laminate without considering the shape of the fiber reinforced plastic to be finally produced. Because it can, there is a big merit in terms of design and work efficiency. In addition, air trapped at the time of lamination is easily degassed by cutting in the thickness direction, voids are not easily generated, and high mechanical properties can be expected. In the present invention, “all of the reinforcing fibers are divided by the incision” means that 95% or more of the number of reinforcing fibers contained in the prepreg base material is divided into 10 to 100 mm.

  As one of the preferred incision forms of the incision prepreg base material, the incision is linear, and the projected length Ws in which the incision is projected in the vertical direction of the reinforcing fiber is 30 μm to 100 mm, and is intermittent and periodic And a cut prepreg substrate disposed over the entire surface. Since the cuts are not continuous but intermittent, the cut prepreg base material does not become loose due to the cuts, and is excellent in handleability during lamination. In addition, when the cuts are periodically arranged, the position of the cut can be controlled, and the physical properties can be controlled. Here, the “projection length Ws obtained by projecting the notch in the vertical direction of the reinforcing fiber” is as shown in FIG. 2, from the notch 4 using the notch 4 as the projection plane in the vertical direction (fiber orthogonal direction 2) of the reinforcing fiber 3. The length 9 when projected perpendicularly to the projection plane (fiber longitudinal direction 1) is indicated. In addition, the expression “arranged over the entire surface” means that the incisions that divide all the reinforcing fibers contained in the entire surface of the incised prepreg base material into a length of 10 to 100 mm are provided.

  The fiber bundle end portion generated by the cutting is likely to become a starting point of fracture due to stress concentration when a load is applied to the fiber reinforced plastic. Therefore, a smaller notch is advantageous in strength. Ws is an index indicating the amount of reinforcing fiber to be divided, and when Ws is 100 mm or less, the strength is greatly improved. However, when Ws is smaller than 30 μm, it may be difficult to control the cutting, and it may be difficult to ensure that L is 10 to 100 mm over the entire discontinuous portion of the reinforcing fiber. That is, if fibers that are not cut by cutting are present in a discontinuous portion that is expected to follow a complicated shape, the fiber may be remarkably lowered in fluidity. There is a problem that the area below 10 mm increases and the strength may be lower than the design value. Conversely, when Ws is greater than 100 mm, the strength is almost constant. That is, when the fiber bundle end becomes larger than a certain value, the load at which breakage starts becomes substantially equal. More preferably, the strength is significantly improved when Ws is 1.5 mm or less. That is, Ws is preferably 1 to 100 mm from the viewpoint that a cut can be inserted with a simple device. On the other hand, in view of the relationship between the ease of cutting control and mechanical properties, Ws is 30 μm. It is preferable that it is -1.5mm, More preferably, it exists in the range of 50 micrometers-1 mm.

  Hereinafter, an example of a preferable cutting pattern will be described with reference to FIG.

  A plurality of controlledly aligned cuts 4 are made on a prepreg base material in which reinforcing fibers are aligned in one direction. The fibers are divided by the pair of cuts in the fiber longitudinal direction 1 and the fiber length L of the reinforcing fibers on the prepreg substrate is substantially 10 to 100 mm by setting the interval 6 to 10 to 100 mm. Can do.

  FIG. 2 shows an example in which both the fiber length L and the projected length Ws obtained by projecting the cut in the vertical direction of the reinforcing fiber are one kind. The row 7a consisting of the first intermittent cuts and the row 7c consisting of the third intermittent cuts can be overlapped by moving L in the fiber longitudinal direction 1 and the second intermittent cuts. The row 7b made of the above and the row 7d made of the fourth intermittent cut can be overlapped by moving in the fiber longitudinal direction 1 in the L direction. Further, there are fibers cut into the first and second cut rows and the third and fourth cut rows, and the presence of the width 5 cut to the fiber length L or less ensures stable In particular, a cut prepreg base material can be produced with a fiber length of 100 mm or less. Several examples of the cut pattern are illustrated in FIGS. 3A to 3F, but any pattern may be used as long as the above conditions are satisfied. In FIG. 3, the arrangement of the reinforcing fibers is not shown, but the arrangement direction of the reinforcing fibers is the vertical direction in FIG. 3 a), b) or c) is a mode in which the cut is in the fiber orthogonal direction 2, and d), e) or f) in FIG. 2 is a mode in which the cut is inclined from the fiber orthogonal direction 2. Show. Among the fibers that are divided into cuts other than the pair of cuts, there are also fibers that are shorter than the fiber length, but such fibers are not included in the fibers having the fiber length L defined in the present invention. And the fewer the fibers of 10 mm or less, the better.

  As described in FIG. 5, the cut prepreg base material used in the present invention is a prepreg base material in which the fibers are aligned in one direction because the resin flow in the 90 ° direction is the driving force of the fiber flow. When two or more layers are laminated in different fiber directions, fluidity in the fiber longitudinal direction is expressed. Therefore, the layer adjacent to the cut prepreg base material is a prepreg base material (including the cut prepreg base material according to the present invention) in which reinforcing fibers are oriented in one direction, and in a fiber direction different from the cut prepreg base material. It is good to be laminated. When it is unavoidable to stack the cut prepreg base materials in the same fiber direction adjacent to each other, it is preferable to stack the cuts so that the cuts do not overlap. Moreover, a resin film etc. may be laminated | stacked between the layers of these cutting prepreg base materials, and fluidity | liquidity may be improved. In addition, a continuous fiber base material can be disposed in a region that does not need to flow, and the mechanical properties of the region can be further improved.

  If the fiber direction is different between layers, a difference occurs in the flow direction and distance of each layer, but the displacement difference can be absorbed by sliding between the layers. That is, even if the fiber volume content Vf is as high as 45 to 65%, the laminate used in the present invention can exhibit high fluidity because the resin can be unevenly distributed between the layers. In the case of SMC, fluidity is different between randomly chopped strands, and they try to flow in different directions, but they are difficult to flow due to interference between fibers, and fluidity is ensured only up to about 40% Vf. Can not do it. That is, the laminate used in the present invention has a characteristic that high fluidity can be expressed even with a high Vf configuration capable of improving mechanical properties. In addition, due to the characteristics of this fluidity, the obtained fiber reinforced plastic can maintain a laminated structure even if it has a complex shape, expresses high elastic modulus and strength, reduces strength variation, and also has impact characteristics. Greatly improved.

  More preferably, the notch prepreg base material is adjacent to two or more layers in succession, and for any two adjacent layers of the two or more layers, the geometric center of any incision on one incision prepreg base material And the other cut prepreg base material are preferably laminated so as to be separated from the geometric center of any cut by 5 mm or more. It is important in two ways that the geometric centers of the notches of adjacent notched prepreg base materials are separated from each other. The first reason is that, when the laminate is stretched during molding, if the cuts are connected to each other, it is easy to tear from there and the molding of the present invention may fail. Moreover, even if it is not torn at the time of molding, there is a possibility of affecting the quality such that the fiber content is lowered and the wall thickness is reduced in the region where the geometric centers of the cut are close to each other. Second, when the fiber reinforced plastic becomes a fiber reinforced plastic, the ends of the reinforced fiber bundles that are cut by the cuts are so-called stress concentration points, so they tend to break, but if the cuts are connected, cracks can easily occur. May be easily connected and the strength may be reduced. FIG. 6 illustrates the relationship between the two layers of the laminated cut prepreg base material, and the geometrical center 8 of the closest cuts among the cuts 4a and 4b in the first layer is shown in FIG. ) To d), preferably 5 mm or more away, both the concerns during molding and the physical properties can be cleared without problems, but when approaching 5 mm as shown in FIG. 6a) The problem may come up. The “geometric center” mentioned here is a point where the first moment is zero around the geometric center point g, and the geometrical center point g is expressed by the following equation for the point x on the notch.

  In order to obtain a cut prepreg base material according to the present invention, as a method of cutting into the prepreg base material, first, a prepreg base material of continuous fibers aligned in one direction is prepared, and then manual operation using a cutter is performed. A method of cutting with a cutting machine or a cutting machine, or a continuous roller prepreg base material manufacturing process that is aligned in one direction, continuously pressing a rotating roller with a blade placed at a predetermined position, or prepreg base material in multiple layers There is a method such as pressing and cutting with a mold in which blades are arranged at predetermined positions. The former is used when cutting a part of the prepreg substrate easily at the molding site, and the latter is used when making a large amount of the cut prepreg substrate in consideration of production efficiency. Is suitable. When a rotating roller is used, the roller may be directly cut out to provide a predetermined blade, but by cutting a flat plate around a magnet roller or the like and winding a sheet-shaped mold with the blade placed at a predetermined position The replacement of the blade is easy and preferable. By using such a rotating roller, it is possible to insert the cut well even with a cut prepreg base material having a small Ws (specifically, 1 mm or less). After making the cut, the cut prepreg base material may be further thermocompression-bonded with a roller or the like to fill and fuse the resin into the cut portion, thereby improving the handleability.

  The characteristics of the fiber reinforced plastic obtained by molding according to the present invention using an example of the cut prepreg base material thus obtained will be described with reference to FIG. A part of a laminate 12 in which a cut prepreg base material 10 in which a cut 4 crosses a fiber 3 in a 90 ° direction is laminated is a), and a fiber reinforced plastic 16 obtained by molding the laminate 12 according to the present invention. Part b) is a plan view showing a close-up of the layer derived from the cut prepreg substrate 10 and a cross-sectional view taken along the line AA of the plan view. The cut prepreg base material 10 in FIG. 7a) is provided with cuts perpendicular to the fibers as shown in FIGS. 3a) to 3c), and the cuts 4 penetrate in the thickness direction of the layers. By setting the fiber length L to 100 mm or less, fluidity is ensured, and the fiber reinforced plastic 16 whose area is easily extended from the laminate 12 can be obtained (however, the thickness is reduced). As shown in FIG. 7b), when the elongated fiber reinforced plastic 16 is obtained, the short fiber layer 17 derived from the cut prepreg base material 10 extends in the fiber vertical direction and has no fiber (cut opening). 18 is generated. This is because the reinforcing fiber generally does not expand at a pressure of the molding level. In the case of FIG. 7, the cut opening 18 is generated by the extended length. As shown in the cross-sectional view, the region 18 is occupied by the adjacent layer 19 that has entered, and the substantially triangular resin-rich portion 20 and the region in which the adjacent layer 19 has entered. For example, when a cut prepreg base material with cuts on the entire surface is arranged on the surface layer of fiber reinforced plastic, there is a feature that the laminate cut opening 18 is observed in the region where the fibers flow. More preferably, all the layers constituting the fiber reinforced plastic are made of a strip-shaped aggregate having a fiber length Lc in the range of 10 to 100 mm and a width Wsc of 30 μm to 150 mm. In the present invention, as shown in a region 35 surrounded by a dotted line in FIG. 7, a region surrounded by two pairs of fiber bundle dividing portions 22 is expressed as a strip shape. The strip-shaped width Wsc, which is the spread width in the vertical direction of the fiber after molding, is extended to a maximum of about 50% by molding with respect to the projected length Ws obtained by projecting the cut of the notched prepreg base material in the vertical direction of the reinforcing fiber. Therefore, Wsc is in the range of 30 μm to 150 mm.

  As the cut prepreg base material suitably used in the present invention other than the cut prepreg base material whose incision is perpendicular to the fibers as shown in FIGS. 3a) to 3c), as shown in FIGS. It is good to incline from the fiber orthogonal direction 2. When making an incision with a rotating roller or the like industrially, if an attempt is made to make an incision in the fiber orthogonal direction 2 into the prepreg base material supplied in the fiber direction, it is necessary to divide the fiber at once, and a large force is required. The durability of the blade is reduced, and the fibers easily escape in the orthogonal direction 2, resulting in an increase in the amount of uncut fibers. On the other hand, since the incision is inclined from the fiber orthogonal direction 2, the amount of fibers to be cut per unit length of the blade is reduced, the fibers can be cut with a small force, the durability of the blade is high, and the uncut fibers can be reduced. Further, since the incision is inclined from the fiber orthogonal direction 2, the projection length Ws obtained by projecting the incision in the vertical direction of the reinforcing fiber can be made smaller than the incision length, and the cutting is divided by each incision. The strength is expected to be reduced by reducing the amount of fibers produced. When cutting in the fiber orthogonal direction 2, it is preferable to prepare a small blade in order to reduce Ws. However, if it is too small, there may be a problem in durability and workability.

  Still another preferred form of the cut prepreg base material is a cut prepreg base material in which the absolute value of the angle Θ formed by the cut with the reinforcing fiber is in the range of 2 to 25 °. In the case of this cut prepreg base material, the cuts are intermittent cuts, and the cuts made with the reinforcing fibers have a small angle Θ, which may be cuts as shown in FIG. 9 or continuous cuts as shown in FIG. But it ’s okay. Even if the absolute value of Θ is larger than 25 °, fluidity can be obtained, and higher mechanical properties can be obtained as compared with conventional SMC, etc., but in particular, when the absolute value of Θ is 25 ° or less. Significant improvement in mechanical properties. On the other hand, even if the absolute value of Θ is smaller than 2 °, sufficient fluidity and mechanical properties can be obtained, but it is difficult to make a stable cut. That is, when the angle of cut with respect to the fiber becomes smaller, the fiber easily escapes from the blade when making the cut, and in order to make the fiber length L 100 mm or less, the absolute value of Θ is 2 °. If it is smaller, at least the shortest distance between the cuts may be less than 0.9 mm, resulting in poor production stability. In addition, when the distance between the cuts is small as described above, there may be a problem that handling at the time of stacking becomes difficult. In view of the relationship between the ease of controlling the cutting and the mechanical characteristics, it is more preferably in the range of 5 to 15 °.

  The incision may be a curve as shown in FIG. 10c), but a straight line is preferable because the flowability is easily controlled. Further, the length L of the reinforcing fiber divided by the cut may not be constant as shown in FIG. 10b), but if the fiber length L is constant as shown in FIG. 10a), the fluidity is controlled. It is preferable because it is easy and can further suppress variation in strength. Here, the prescribed linear shape means a state in which a part of a geometrical straight line is formed, but unless the effect of facilitating the control of the fluidity is impaired, the geometrical Even if there is a portion that does not form a part of the straight line, there is no problem. As a result, even if there is a portion where the fiber length L is not constant over the entire surface (in this case, the fiber length L is substantially over the entire surface). It can be said that it is constant).

  As a preferable example [1], as shown in FIG. 8 and FIGS. 10a) to 10c), the cuts 4c are preferably continuously formed. In the pattern of Example [1], since the cut 4c is not intermittent, flow disturbance does not occur in the vicinity of the cut end, and in the region where the cut 4c is made, all the fiber lengths L can be made constant, The flow is stable. When the cut is provided on the entire surface of the prepreg base material, since the cuts 4c are continuously formed, the cut prepreg base material 10 is cut into the peripheral portion of the cut prepreg base material in order to prevent the cut prepreg base material 10 from being separated. It is possible to improve the handleability by providing a region where no is connected, or by gripping it with a support such as a sheet-like release paper or film that is not cut. Moreover, in order to improve the handleability at the time of lamination | stacking, as a two-layer laminated body which laminated | stacked two sheets of the said cutting prepreg base material which cut | notched continuously beforehand like FIG. Also good.

In addition, as another preferable example [2], as shown in FIG. 9, when the length 9 projected in the vertical direction of the reinforcing fiber is Ws, the intermittent cut 4d in which Ws is in the range of 30 μm to 100 mm is provided. The notch prepreg base material 10 is provided on the entire surface, and the notch 4d ₁ and the notch 4d ₂ adjacent in the fiber longitudinal direction of the notch 4d ₁ may have the same geometric shape. FIG. 9 shows an example in which both L and Ws are one type. Any of the cuts 4d (for example, 4d ₁ ) has another cut 4d (for example, 4d ₂ ) that overlaps by translating in the fiber direction. The fiber length can be stably increased by the presence of the width 5 in which the fibers are divided by the adjacent incisions at a fiber length shorter than the fiber length L divided by the cuts 4d that form pairs in the fiber direction. The cut prepreg base material 10 can be manufactured at 100 mm or less. In the pattern of Example [2], when the obtained cut prepreg base material 10 is laminated, the cut is intermittent, and thus the handleability is excellent. Although other patterns are illustrated in FIGS. 10D) and 10E, any pattern may be used as long as the above conditions are satisfied.

  The characteristics of the fiber reinforced plastic 16 of the fiber reinforced plastic obtained by molding according to the present invention using the cut prepreg base material of the preferable example [1] thus obtained will be described with reference to FIG. A) a part of the laminate 12 in which the cut prepreg base material 10 according to the present invention is laminated, and b) a part of the fiber reinforced plastic 16 of the fiber reinforced plastic obtained by molding the laminate 12 according to the present invention. The cross-sectional view which cut out the AA cross section of the top view which closed the layer derived from the cut prepreg base material 10, respectively, and the top view was shown. As shown to a), the notch prepreg base material 10 is provided with the notch 4c whose angle with the fiber 3 is 25 degrees or less over the entire surface, and the notch 4c penetrates the thickness direction of the layer. By setting the fiber length L to 100 mm or less, fluidity is ensured, and the fiber reinforced plastic 16 whose area is easily extended from the laminate 12 can be obtained. When the stretched fiber reinforced plastic 16 is obtained as in b), the short fiber layer 17 derived from the cut prepreg base material 10 stretches in the vertical direction of the fiber, and the fiber 3 itself rotates 24 to expand the stretched region. In order to increase the area, a region (incision opening) 18 in which no fiber exists as shown in FIG. 7 is not substantially generated, and the area on the surface of the layer of the incision opening is 10% or less compared to the surface area of the layer. is there. Therefore, as can be seen from the sectional view, the adjacent layer 19 does not enter, and the fiber-reinforced plastic 16 having high rigidity, high strength, and high quality without the undulation of the layer and the resin rich portion can be obtained. Since the fibers 3 are arranged all over the surface, there is no difference in rigidity in the surface, and the design can be easily applied as in the conventional continuous fiber reinforced plastic. A further epoch-making effect of obtaining a fiber-reinforced plastic having no layer waviness when the fiber rotates and stretches can be obtained only when the absolute value of the angle Θ formed with the cut fiber is 25 ° or less. Further, in terms of strength, when attention is paid to the fibers oriented to about ± 10 ° or less from the load direction as described above, the fiber bundle end portion 22 lies down with respect to the load direction as shown in FIG. I can see the situation. Since the fiber bundle end portion 22 is slanted in the layer thickness direction, load transmission is smooth, and peeling from the fiber bundle end portion 22 hardly occurs. Therefore, further improvement in strength is expected compared to FIG. The fiber bundle end 22 is inclined in the layer thickness direction because when the above-mentioned fiber rotates, there is a gentle distribution in the rotation 24 of the fiber 3 from the upper surface to the lower surface due to friction between the upper surface and the lower surface. It is considered that the presence distribution of the fibers 3 occurs in the layer thickness direction, and the fiber bundle end 22 is inclined in the layer thickness direction. In such a layer of fiber reinforced plastic 16, a fiber bundle end portion that is slanted in the layer thickness direction is formed, and a further breakthrough effect of remarkably improving the strength is the absolute value of the angle Θ formed with the fiber 3 of the cut 4c. Can be obtained for the first time when it is 25 ° or less.

  On the other hand, in FIG. 12, a part of the laminate 12 in which the cut prepreg base material 10 of the preferred example [2] is laminated is a), and a part of the fiber reinforced plastic 16 in which the laminate 12 is molded is b). The top view which each closes up the layer derived from the cutting prepreg base material 10 was shown. As shown in a), the cut prepreg substrate 10 is provided with intermittent cuts 4d having an absolute value of the angle Θ between the fibers 3 of 25 ° or less, and the cuts 4d penetrate the thickness direction of the layer. ing. By setting the fiber length L to 100 mm or less over the entire surface of the cut prepreg base material 10 by the cuts 4d, the fluidity can be secured and the fiber reinforced plastic 16 whose area is easily extended from the laminate 12 can be obtained. By reducing the cut length and the cut angle, the projected length Ws obtained by projecting the cut in the vertical direction of the reinforcing fiber can be made 1.5 mm or less. When the stretched fiber reinforced plastic 16 is obtained as in b), the short fiber layer 17 derived from the cut prepreg base material 10 does not stretch in the fiber direction when stretched in the fiber vertical direction. A non-existing region (cut opening) 18 is generated, but the adjacent short fiber group flows in the fiber vertical direction, thereby filling the cut opening 18 and reducing the area of the cut opening 18. This tendency is particularly remarkable when the projection length Ws obtained by projecting the cut in the vertical direction of the reinforcing fiber is 1.5 mm or less, and the cut opening 18 is not substantially generated, and the layer of the cut opening 18 is not formed. The area on the surface can be in the range of 0.1 to 10% compared to the surface area of the layer. Therefore, an adjacent layer does not penetrate in the thickness direction, and a fiber-reinforced plastic 16 having high rigidity, high strength, and high quality without layer waviness and resin-rich portion can be obtained. Since the fibers 3 are arranged all over the surface, there is no difference in rigidity in the surface, and the design can be easily applied as in the conventional continuous fiber reinforced plastic. The epoch-making effect of filling the cut opening 18 with the flow in the vertical direction of the fiber to obtain a fiber reinforced plastic 16 without layer undulation is that the absolute value of the cut angle Θ is 25 ° or less and the cut is perpendicular to the reinforcing fiber. It can be obtained for the first time by setting the projection length Ws projected in the direction to 1.5 mm or less. More preferably, when Ws is 1 mm or less, higher rigidity, higher strength, and higher quality can be obtained, and application as an outer plate member is also possible.

  Furthermore, it is preferable for the fluidity improvement that the laminate is composed only of the cut prepreg base material. More preferably, the laminate is composed of only a cut prepreg base material, and all the fiber lengths L of the reinforcing fibers constituting the cut prepreg base material are within a range of 10 to 100 mm. Making the incision according to the shape is very time-consuming in terms of design and work. For quality stability, the entire surface is incised so that any area of the laminate can easily follow the complicated shape. It is preferable to keep it. In addition, by cutting the entire surface, even if the laminate has a flat plate shape, the laminate is stretched as a whole and becomes a fiber reinforced plastic in which fibers are spread all over. it can. Further, the laminate can be prepared smaller than the cavity of the mold, and the mold clamping can be easily performed without the laminate being caught between the molds.

  Examples of the reinforcing fibers used for the cut prepreg base material according to the present invention include, for example, organic fibers such as aramid fibers, polyethylene fibers, polyparaphenylene benzoxador (PBO) fibers, glass fibers, carbon fibers, silicon carbide fibers, Examples include inorganic fibers such as alumina fibers, Tyranno fibers, basalt fibers, ceramic fibers, metal fibers such as stainless steel fibers and steel fibers, and other reinforcing fibers using boron fibers, natural fibers, modified natural fibers, etc. . Among them, carbon fiber is particularly lightweight among these reinforcing fibers, and has particularly excellent properties in specific strength and specific modulus, and is also excellent in heat resistance and chemical resistance. It is suitable for members such as automobile panels that are desired to be made. Among these, PAN-based carbon fibers that can easily obtain high-strength carbon fibers are preferable.

  Examples of the matrix resin used for the cut prepreg base material according to the present invention include an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, an epoxy acrylate resin, a urethane acrylate resin, a phenoxy resin, an alkyd resin, and a urethane resin. , Thermosetting resins such as maleimide resin and cyanate resin, polyamide, polyacetal, polyacrylate, polysulfone, ABS, polyester, acrylic, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene, polypropylene, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), liquid crystal polymer, vinyl chloride, thermoplastic resin such as polytetrafluoroethylene, thermoplastic resin such as silicone And the like. Among these, it is particularly preferable to use a thermosetting resin. Since the matrix resin is a thermosetting resin, the cut prepreg base material has tackiness at room temperature, so when the base material is laminated, it is integrated with the upper and lower base materials by adhesion, It can shape | mold, keeping the laminated structure as it was.

  Moreover, the cut prepreg base material according to the present invention may be in close contact with the tape-like support. The base material into which the cut has been inserted can retain its shape even when all the fibers are cut by the cut, and there is no problem that the fibers fall off during shaping. More preferably, the matrix resin is a thermosetting resin having tackiness. Here, the tape-like support includes papers such as kraft paper, polymer films such as polyethylene / polypropylene, metal foils such as aluminum and the like, and in order to obtain releasability from the resin, silicone. A surface or a “Teflon (registered trademark)” release agent or metal deposition may be applied to the surface.

More preferably, among thermosetting resins, an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, an acrylic resin, or a mixed resin thereof is preferable. The resin viscosity at normal temperature (25 ° C.) of these resins is preferably 1 × 10 ⁶ Pa · s or less, and within this range, a prepreg base material having tackiness and draping properties suitable for the present invention. Can be obtained. Among them, the epoxy resin is most excellent in mechanical properties as a reinforced fiber composite material obtained in combination with carbon fiber.

  As a molding condition when a thermosetting resin is used as a matrix resin suitable for the present invention, the mold temperature T1 in the molding process and the mold temperature T2 in the demolding process are made substantially constant. Is good. The temperature of the mold is represented by the average of the temperatures measured by a thermocouple at a plurality of points on the surface of the cavity that touches the laminate (when there are upper and lower molds, at least one point is measured). Here, that the mold temperature T in the present invention is substantially constant means that the variation of the mold temperature is usually within a range of ± 10 ° C. Further, both T1 and T2 should not change over time.

In the present invention, the fiber reinforced plastic has a mold temperature T with respect to an exothermic peak temperature Tp based on differential scanning calorimetry (DSC) of a thermosetting resin used for a prepreg substrate.
Tp−60 ≦ T ≦ Tp + 20 (I)
It is preferable to manufacture within the range. More preferably,
Tp-30 ≦ T ≦ Tp (II)
Is within the range. When the mold temperature T is lower than Tp-60, the time required for curing of the resin becomes very long, and the curing may be insufficient. On the other hand, when it is higher than Tp + 20, a rapid reaction of the resin may cause generation of voids inside the resin and poor curing. In addition, exothermic peak temperature Tp based on DSC in this invention was performed according to JISK7121 (1987), and it heated up on the conditions of the temperature increase rate of 10 degree-C / min at the temperature of 30-180 degreeC. This is a value obtained by taking the peak of the exothermic curve. The test piece referred to in JIS K 7121 (1987) is a paste in the present invention. Therefore, “condition adjustment of test piece” and “test piece” can be referred to as “condition adjustment of paste” and “paste”, respectively. In principle, the state of the paste is adjusted to stand for 6 to 8 hours at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and no heat treatment is performed. In addition, since the paste is measured in the form of a paste, there is no regulation regarding the dimensions.

  In the present invention, the thermosetting resin used for the prepreg base material is preferably produced with a minimum viscosity of 0.1 to 100 Pa · s based on dynamic viscoelasticity measurement (DMA). More preferably, it is 0.1-10 Pa.s. When the minimum viscosity is less than 0.1 Pa · s, only the resin flows during pressurization, and the reinforcing fiber may not be sufficiently filled up to the tip of the protrusion. On the other hand, when the viscosity is higher than 100 Pa · s, the fluidity of the resin is poor, and thus the reinforcing fibers and the resin may not be sufficiently filled up to the tip of the protrusion. The minimum viscosity due to DMA in the present invention is a rotational viscometer, using parallel plates with a radius of 20 mm, a distance between parallel plates of 1 mm, a measurement start temperature of 40 ° C., and a temperature increase rate of 1.5 ° C./min. Measured under the condition of a measurement frequency of 0.5 Hz, the value of the lowest viscosity observed.

  Specific examples of more preferable production methods will be described below.

  For example, the mold is a single-sided mold, a laminated body is placed on the single-sided mold, a stretchable film is covered on the laminated body, the laminated body is sealed, and lamination is performed by the differential pressure between the sealed space and the outside air. The body is preferably pressed against a single-sided mold. In the example of FIG. 13, the flat laminated body 12 is disposed on the single-sided mold 28c, and the single-sided mold 28c and the stretchable film 32 are sealed with a sealant 31 or the like leaving a pipe serving as a deaeration port 26, and vacuumed. The sealed space 30 is depressurized using a pump or the like, and the laminate 12 is pressed against the single-sided mold 28c by a differential pressure from the atmospheric pressure. Furthermore, this set is put in a pressure vessel such as an autoclave, and the laminate 12 is pressed against the single-sided mold 28c with a differential pressure (about 0.1 to 0.6 MPa) between the pressure in the pressure vessel and the sealed space 30. Also good. The production method of the present invention using a single-sided mold is preferable because the mold cost is lower than that of a double-sided mold and the like, and molding is possible without introducing a large facility such as a mold elevator. The film may be disposable for each molding, but mass production can be handled by using a durable silicone rubber film or the like as an openable lid instead. Stretchable film may be uneasy about heat resistance, so when molding with thermosetting resin, it is demolded when the fiber reinforced plastic has a demoldable hardness and post-cured in an oven, etc. May be. In the case of molding using a thermoplastic resin, the mold is removed when the fiber reinforced plastic has a demoldable hardness, and is fixed by another jig (such as a jig that can correct a large amount of fiber reinforced plastic) and then annealed. May be.

  For example, the mold may be composed of two or more molds, and when the laminate is pressed against the mold by clamping, the continuous fibers may be arranged in a region where the laminate first contacts both the two molds. Of the laminate, the region where the continuous fibers are arranged is difficult to flow. Therefore, it is easy to control the flow by first bringing the non-flowing part into contact with the mold and fixing it as a reference. Specifically, as shown in FIG. 14, in a molding die including a split die 28 d that is a flat die having holes accessible to the upper die 28 a, the lower die 28 b, and the lower die 28 b, the laminated body 12. Is placed on the split mold 28d supported by the spring 27. First, the upper mold 28a and the split mold 28d are brought into contact with each other. At this time, the laminated body 12 is arranged to fill the cavity, and continuous fibers are arranged in the periphery of the laminated body 12. Accordingly, the peripheral portion of the laminate 12 that first contacts the upper mold 28a does not flow and is fixed. Thereafter, the lower mold 28b is pushed by the laminate 12, and the central portion of the laminate 12 is stretched to obtain a fiber reinforced plastic. By arranging continuous fibers in the periphery and clamping from there, the starting point of the flow is fixed, and by controlling the flow, a uniform fiber flow can be realized, and high-quality fiber-reinforced plastic can be produced with fewer defective products. By using a double-sided mold, the heat capacity is large and the quality is easy to stabilize. Moreover, if a demolding mechanism is provided, it is excellent in mass productivity.

  For example, after the lamination step, prior to the molding step, the laminate may be pre-shaped into a substantially fiber-reinforced plastic shape after molding, and then the laminate may be placed on the mold. When forming a complex shape, pre-apply by simple operations such as bending without actively stretching the cut prepreg base material after creating the laminate in a flat plate shape and before placing it in the mold. Molding facilitates positioning when placed in the mold and makes it possible to obtain a fiber-reinforced plastic having a stable quality by clarifying the extending direction. As a pre-molding means, it may be bent as it is at room temperature or may be pressed by a double-sided mold. Preferably, even if the matrix resin is a thermosetting resin or a thermoplastic resin, The laminated body is preferably sealed with a single-sided mold and a silicon rubber film, and pressed against the single-sided mold by decompressing the sealed space. At this time, in order to soften the flat laminate, the laminate itself may be heated at a relatively low temperature so that the matrix resin does not cure and deteriorate, and may be pressed against a lower temperature single-sided mold. The laminate may be pressed against a single-sided mold heated at a relatively low temperature so that the matrix resin does not harden or deteriorate, and once pre-molded, the mold may be quenched.

  More preferably, after the lamination step, the laminate is pre-shaped into a single contour shape prior to the molding step. Here, “single contour shape” refers to the type of uneven shape, and when the surface of the laminate is taken out as a quadric surface, it is a point on the quadric surface and an arbitrary plane passing through the point. When referring, it refers to a set of points where there is only one intersection line where the intersecting line passing through the point is a straight line among the intersecting lines of the plane and the quadric surface, specifically, a conical shape or a cylindrical shape, Some of them apply. If it is a single contour shape, even if it is not accompanied by the extension of the cut prepreg base material, it can be followed if it is a certain shape. For example, in producing the fiber reinforced plastic 16 shaped like a lunch box lid as shown in FIG. 18b), the laminate 12 made into a flat shape as shown in FIG. 18a) was pre-shaped into a U-shape. If it arrange | positions later in the shaping | molding die 28b, positioning is easy and the direction which the laminated body 12 expand | extends at the time of shaping | molding can be controlled, and it is preferable.

  In producing fiber reinforced plastic according to the present invention, the reinforced fiber has an angle of ± 10 ° or less (within a range of −10 ° to 10 °) from the direction of the smallest curvature of the concavo-convex portion in the concavo-convex portion of the fiber reinforced plastic. It is preferable that the layer oriented is thicker than other layers. When attention is paid to the cross section 40 of the R portion corresponding to the concavo-convex portion of the fiber reinforced plastic 16 in FIG. 18b), as shown in FIG. 19, a region 42 having a thick layer thickness in the R portion is seen in the layer 41 whose depth is in the fiber orientation direction. In the uneven portion such as the R portion, the layer thickness is not uniform due to the difference in curvature between the outer surface and the inner surface, and the direction of small curvature of the uneven portion that is more easily flowable by using the manufacturing method of the present invention ( In the case of FIG. 19, there is a thick layer of fibers oriented at an angle of ± 10 ° or less from the depth direction). In general, the concavo-convex shape is designed with the intention of improving the bending rigidity by the standing surface, and it is preferable that the fiber is oriented in the direction with the smallest curvature of the concavo-convex portion, that is, in the direction parallel to the standing surface. .

  Moreover, an assembly cost can be reduced by embedding, hardening, and integrating a metal insert in the discontinuous portion 37 of the laminate 12 shown in FIG. 4 for the purpose of providing a mechanism such as a rotating portion. At that time, by providing a plurality of recesses around the metal insert, the flowed fibers can enter the recesses, and can easily fill the gaps. And can be firmly integrated.

  The fiber-reinforced plastics manufactured according to the present invention are used for shafts and heads of sports parts such as bicycle equipment and golf, automobile parts such as doors and seat frames, and robots that require strength, rigidity and light weight. There are mechanical parts such as arms. In particular, in addition to strength and light weight, the member shape is complicated, and the present invention can be preferably applied to automobile parts such as seat panels and seat frames that require shape followability like this material.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the inventions described in the examples.

Example 1
<Preparation of prepreg base material>
An epoxy resin composition was obtained by the following procedure.

  (A) Epoxy resin (“Epicoat (registered trademark)” 828: 30 parts by weight, Epicoat 1001: 35 parts by weight, Epicoat 154: 35 parts by weight) manufactured by Japan Epoxy Resin Co., Ltd., and thermoplastic resin polyvinyl formal (Chisso ( "Vinylec (registered trademark)" K) 5 parts by weight was stirred for 1 to 3 hours while heating at 150 to 190 ° C to uniformly dissolve polyvinyl formal.

  (B) After lowering the resin temperature to 55 to 65 ° C., 3.5 parts by weight of a curing agent dicyandiamide (DICY7 manufactured by Japan Epoxy Resin Co., Ltd.) and a curing accelerator 3- (3,4-dichlorophenyl) -1, 4 parts by weight of 1-dimethylurea (DCU99 manufactured by Hodogaya Chemical Co., Ltd.) was added, kneaded at the temperature for 30 to 40 minutes, and then taken out from the kneader to obtain an epoxy resin composition.

  The obtained epoxy resin composition was apply | coated on the release paper using the reverse roll coater, and the resin film was produced.

Next, the carbon fiber (tensile strength 4,900 MPa, tensile elastic modulus 235 GPa) aligned in one direction in a sheet shape is laminated with two resin films from both sides of the carbon fiber, heated and pressurized to impregnate the resin composition. Thus, a unidirectional prepreg base material having a carbon fiber basis weight of 150 g / m ² and a resin weight fraction of 33% (corresponding to a fiber volume content Vf of 58%) was produced.

  The exothermic peak temperature Tp according to DSC of the obtained epoxy resin composition was 152 ° C. As a measuring apparatus, DSC2910 (product number) manufactured by TA Instruments Inc. was used, and the measurement was performed under a temperature rising rate of 10 ° C./min.

  The minimum viscosity due to DMA was 0.5 Pa · s. As a measuring device, a dynamic viscoelasticity measuring device “ARES” manufactured by T.A. Instruments Co., Ltd. was used under the conditions of a temperature rising rate of 1.5 ° C./min, a frequency of 0.5 Hz, and a parallel plate (radius 20 mm). The minimum viscosity was determined from the temperature-viscosity relationship curve.

<Introduction of cut into prepreg base material>
A cut prepreg base material having regular cuts at regular intervals was obtained by inserting cuts as shown in FIG. 16 into the prepreg base material using an automatic cutter. The cutting direction is the fiber orthogonal direction 2, the cutting length W is 10.1 mm (that is, Ws = 10.1 mm), and the interval L (fiber length) is 30 mm. As shown in FIG. 16, adjacent cut rows 7a and 7b are geometrically equivalent when moved 10 mm in the direction perpendicular to the fiber. In addition, there are pairs of cuts 7a and 7c and 7b and 7d in the cut rows that are paired in the fiber longitudinal direction, and there are two patterns of cut rows. Furthermore, the range of 5 in which the cuts in the adjacent rows cut into each other is 0.1 mm.

<Molding of fiber reinforced plastic>
As shown in FIG. 15, two double contour portions 25 (a shape in which R200 mm and R300 mm spheres protrude from the head, with circles having a diameter of 100 mm and a diameter of 150 mm as boundaries, respectively) are provided on a rectangular plate of 300 × 200 mm. Fiber reinforced plastic 16 was molded.

When the longitudinal direction of the rectangle is 0 °, the cut prepreg substrate is rectangular (270 ×) in the orientation direction of the carbon fiber (0 ° direction) and the direction shifted 45 degrees to the right from the orientation direction of the carbon fiber (45 ° direction). 180 mm) and 16 layers were laminated in a [45/0 / −45 / 90] _2S laminate structure to obtain a 270 × 180 mm flat laminate.

  The mold consists of an upper mold and a lower mold, and the cavity when both molds are combined is designed to determine the outer shape of the final molded product. The mold was placed in a press machine, and the upper mold was moved up and down to open and close the mold. The temperature was controlled at 150 ° C. so that the temperature T1 of the mold in the molding step was substantially the same as the exothermic peak temperature Tp due to DSC of the epoxy resin composition used for the prepreg substrate. The laminate was placed on the lower mold approximately at the center of the cavity, and the mold was clamped. The press pressure at this time was adjusted so that the pressure divided by an area of 300 × 200 mm was 6 MPa. Since the laminate was made smaller than the cavity, there was an advantage that it took less time and effort to arrange. After being left in the mold for 30 minutes, the mold was opened at 150 ° C. without lowering the temperature T2 of the mold in the demolding process from T1, and the fiber reinforced plastic 16 was demolded.

  Although the laminate was smaller than the cavity, the fiber flowed to every corner, and a fiber reinforced plastic having a plurality of double contour portions along the outer shape of the mold could be obtained. Because of its three-dimensional shape, it became a highly rigid and lightweight fiber-reinforced plastic. Not only a double contour part, but also a strip-shaped opening that is stretched as a whole and cut between the fiber bundle ends divided by cutting, and has a fiber length Lc of 30 mm and a width Ws of about 11 to 15 mm. Fiber bundles were distributed throughout. In particular, in the shape having two or more double contour parts, since the fiber always stretches in the molding using the continuous fiber base material, it is essential to shape the laminated body in advance to the molding die before molding as the shaping process. Even if a shaping process is adopted, it is extremely difficult to eliminate the deterioration of the surface quality due to wrinkles and fiber tension. As in the present invention, the man-hour reduction effect of obtaining a high-quality fiber-reinforced plastic without positioning a flat base material with high accuracy is very large.

(Example 2)
A 34 μm-thick film using a flat plate press heated at 200 ° C. with pellets of a copolymerized polyamide resin (“Amilan” (registered trademark) CM4000 manufactured by Toray Industries, Inc., polyamide 6/66/610 copolymer, melting point 155 ° C.) Processed into a shape. The viscosity of the polyamide resin in an atmosphere at 25 ° C. was a solid and could not be measured, and the substrate had no tackiness. A prepreg base material was prepared in the same manner as in Example 1 except that the release paper was not used. A cut was introduced into the prepreg base material in the same manner as in Example 1 to obtain a cut prepreg base material, and then a laminate was obtained in the same manner as in Example 1. However, since there was no tack, the laminate was not integrated and was simply in a state of 16 layers. The temperature of a double-sided mold similar to that in Example 1 is controlled at 70 ° C. On the other hand, the laminate was placed in an oven heated to 200 ° C., taken out when the surface temperature reached 160 ° C., placed on the lower mold, and clamped at once. The press pressure at this time was adjusted so that the pressure divided by an area of 300 × 200 mm was 6 MPa. Since the laminate was made smaller than the cavity, it could be placed easily and cold-pressed before the temperature of the laminate fell. After leaving in the mold for 90 seconds, the mold was removed. Since it was a cold press, demolding was very easy.

  Although the laminate was smaller than the cavity, the fiber flowed to every corner, and a fiber reinforced plastic having a plurality of double contour portions along the outer shape of the mold could be obtained. Because of its three-dimensional shape, it became a highly rigid and lightweight fiber-reinforced plastic. Not only a double contour part, but also a strip-shaped opening that is stretched as a whole and cut between the fiber bundle ends divided by cutting, and has a fiber length Lc of 30 mm and a width Ws of about 11 to 15 mm. Fiber bundles were distributed throughout. Although some voids were observed between the layers, molding with extremely fast cycle time could be demonstrated using the present invention, although the mechanical properties may not be superior to those of Example 1.

(Example 3)
In the same manner as in Example 1, a prepreg base material was produced. A linear notch in a direction of 10 ° was continuously inserted into the prepreg base material from the fiber as shown in FIG. 8 using an automatic cutter. As shown in FIG. 17, the prepreg base material thus obtained was laminated on the front and back so that the fiber directions were the same and the cuts intersected (in the directions of 10 ° and −10 °), and the prepreg base was formed by continuous cutting. Prevented the material from falling apart. This two-layer laminate was cut into rectangles (270 × 180 mm) in the direction of each of eight sets, and laminated in a pseudo isotropic manner ([45/45/0/0 / −45 / −45 / 90/90] _S ). A flat laminate of 270 × 180 mm was obtained. Next, molding was performed in the same manner as in Example 1 to obtain a fiber reinforced plastic.

  The obtained fiber reinforced plastic was molded into a shape as designed in the same manner as in Example 1. Even in the cut portion on the surface, almost no cut opening is seen, and there is almost no region where the reinforcing fiber is not present and the resin is rich, or the reinforcing fiber of the adjacent layer is excluded, and the appearance quality is good. And obtained smoothness. The fiber direction was rotated from the time when the laminated body was arranged, and it was assumed that the rotation cut the filling opening and became a smooth fiber reinforced plastic.

Example 4
A prepreg base material was prepared in the same manner as in Example 1. By using an automatic cutting machine, a 1 mm linear cut is intermittently inserted into the prepreg base material in the direction of 20 ° from the fiber as shown in FIG. 9 to project the cut in the vertical direction of the reinforcing fiber. The projected length Ws was 0.34 mm. The fibers were cut by the pair of cuts 4d ₁ and 4d ₂ , and the fiber length L was 30 mm over the entire surface of the obtained cut prepreg base material. The cut prepreg base material thus obtained was cut out in the same manner as in Example 1, laminated and molded to obtain a fiber reinforced plastic.

  As shown in FIG. 12 b), the obtained fiber-reinforced plastic filled the cut opening 18 while the fiber 3 was slightly swelled, and the cut opening 18 was hardly seen on the surface. Good appearance quality and smoothness were obtained.

(Example 5)
Using a molding apparatus as shown in FIG. 13, a fiber reinforced plastic shaped like a lid of an elliptical lunch box was molded. In the same manner as in Example 1, a prepreg base material was produced, a cut was introduced, a cut prepreg base material was produced, and laminated and integrated to produce a laminate 12.

  As a forming die, a single-sided die 28c having a convex portion (double contour portion 25) shaped like the final shape shown in FIG. 13 and a groove 33 around it was prepared. A sealant 31 is arranged around the single-sided mold 28c, and a polyamide heat-resistant tube connected to a vacuum pump is disposed on the sealant 31 to form a deaeration port 26, which is heated in an oven controlled at 150 ° C. . When the single-sided mold 28c becomes constant at 150 ° C., the laminated body 12 smaller than the surface area of the convex portion is disposed at the approximate center on the convex portion, and the elastic silicone rubber film 32 is quickly put on and closely adhered with the sealant 31. A sealed space 30 was formed between the film 32 and the mold 28c. At the same time, the vacuum pump is activated, the vacuum 38 is performed, the exhaust air is exhausted from the deaeration port 26, and the laminated body 12 softened by the differential pressure (about 0.1 MPa) between the outside air and the sealed space 30 is expanded to form the mold 28c. To form a hot drape. Due to the presence of the grooves 33, the film 32 was firmly in the shape up to the base of the convex portion, and pressure was firmly applied to the base of the convex portion. After leaving in the oven for 30 minutes, the entire molding apparatus was taken out of the oven, the film 32 was broken, and the fiber reinforced plastic was removed from the mold 28c.

  Although the laminated body 12 had a flat plate shape smaller than the obtained fiber reinforced plastic, a fiber reinforced plastic having a shape like an elliptical lunch box lid could be obtained as designed. Since the molding pressure was smaller than in Examples 1 and 2, the double contour part was clearly transferred, although it was not greatly expanded, and a fiber-reinforced plastic with good surface quality could be obtained.

(Example 6)
Using a mold as shown in FIG. 14, a double contour part (a shape in which an R800 mm sphere protrudes from a circle with a diameter of 350 mm as a boundary line) on a square plate of 500 × 500 mm as shown in FIG. A fiber reinforced plastic provided in the center was molded.

A prepreg base material was produced in the same manner as in Example 1, and first cut into 500 × 500 mm squares in the directions of 0 ° and 45 °. A notch similar to that in Example 1 was cut in the center of the square in a range of 360 mm in diameter to form a region composed of only reinforcing fibers having a fiber length of substantially 25 mm. 16 layers were laminated | stacked by the laminated structure of [45/0 / -45 / 90] _2S similarly to Example 1, and the flat laminated body of 500x500 mm was obtained. A region composed only of 25 mm reinforcing fibers overlapped with each other, and a discontinuous portion 37 was formed in the range of the central portion diameter of 360 mm of the laminate as shown in FIG. 1a).

  The molding die is formed of a split die 28d supported by a spring 27 together with an upper die 28a and a lower die 28b. The lower die 28b is a die that determines the shape of only the double contour portion 25, and the split die 28d is a shape in which a flat plate is hollowed out so that the lower die 28b can access the upper die 28a, and the shape of the flat plate portion is determined. The type to be. The split mold 28d is supported by a spring, and is above the lower mold 28b when the mold is open. The temperature of the entire mold was controlled at 150 ° C. in the same manner as in Example 1, and the laminate 12 was placed on the split mold 28d. At this time, since the size of the laminate 12 and the size of the cavity were the same, the laminate 12 was positioned with high precision. Next, the upper die 28a was lowered, and first, it was brought into contact with the periphery of the laminate 12 and the split die 28d. The periphery of the laminate 12 is a region 36 in which continuous fibers are arranged, and the fibers hardly flow. Therefore, the fibers in the region 36 are fixed at this stage and become the starting point of the extension of the laminate 12. Further, by pushing the upper die 28a, the shape of the double contour part 25 was determined by the lower die 28b and the upper die 28a, and the cavity of the molding die was closed. The pressing pressure at this time was adjusted so that the pressure divided by an area of 500 × 500 mm was 6 MPa. In the same manner as in Example 1, the fiber-reinforced plastic was removed from the mold after being left in the mold for 30 minutes.

  A fiber reinforced plastic having a double contour portion along the outer shape of the mold could be obtained. Similar to Example 1, the surface quality is good, only the double contour part is stretched, the notch opening existing between the fiber bundle ends divided by the notch, the fiber length Lc is 30 mm, and the width Ws is 11 to 15 mm. Strip-like fiber bundles with a degree of distribution were concentrated in the double contour part. Moreover, the peripheral part of the laminated body 12 hardly flowed, it was molded according to the cavity, and a fiber-reinforced plastic was obtained without trim.

(Example 7)
A fiber reinforced plastic 16 like a lid of a 150 × 150 × 20 mm rectangular lunch box as shown in FIG. Using the same prepreg base material as in Example 1, a straight cut of 1 mm (Ws is 0.34 mm) is made in the direction of 20 ° from the fiber as shown in FIG. A cut prepreg base material having a fiber length L of 30 mm over the entire surface was prepared. The cut prepreg base material thus obtained was cut into a rectangle (190 × 150 mm) and laminated in a [45/0 / −45 / 90] _2S laminate structure to obtain a flat laminate of 180 × 150 mm. It was. Next, a flat laminate was placed on the lower die 28b of the mold, and an iron whose temperature was controlled at 80 ° C. was pressed, and the laminate was folded back by 15 mm at the R portion to form a U-shape. After removing the laminated body 12 pre-shaped in the single contour shape thus obtained from the lower mold 28b, the temperature of the mold was controlled at 150 ° C. When both the upper and lower molds reached 150 ° C., the pre-shaped laminate 12 as shown in FIG. 18 a) was placed in the lower mold 28 b, and the mold was clamped, and the pressure was divided by an area of 150 × 150 mm. A pressure of 6 MPa was applied, and the fiber reinforced plastic 16 was demolded after 30 minutes.

  The obtained fiber reinforced plastic 16 was satisfactorily filled with fibers including two standing surfaces as shown in FIG. 18b). Since two standing surfaces were filled by the pre-shaping, it was assumed that the extension direction of the laminated body 12 was controlled, and the fiber-reinforced plastic 16 having a stable quality was obtained. Further, when the R-section cross section 40 at the corner of the standing surface and the plane filled at the time of molding was observed, a laminated structure (including some undulations) that did not change from the plane despite being filled at the time of molding as shown in FIG. ) Was generated. In particular, with respect to the layer 41 whose depth is in the fiber orientation direction, there was an uneven region 42 where the layer thickness was locally thick at the R portion. Thereby, it was estimated that the bending rigidity of the whole fiber reinforced plastic 16 improved.

(Example 8)
A fiber-reinforced plastic 16 like a donut-shaped window frame as shown in FIG. 20c) was autoclaved with a single-sided mold. Using the same prepreg base material as in Example 1, a straight cut of 1 mm (Ws is 0.34 mm) is made in the direction of 20 ° from the fiber as shown in FIG. A cut prepreg base material having a fiber length L of 30 mm over the entire surface was prepared. The cut prepreg base material obtained in this way may be cut along the outline of the fiber reinforced plastic 16 and laminated to create a laminate, and after molding the fiber reinforced plastic, the center portion may be trimmed. Since the yield is poor, the cut prepreg base material 10 is cut in a cut pattern as shown in FIG. 20a) so that the abutting position 39 of the cut prepreg base material is oblique, and the cut prepreg base material 10 is formed into a donut shape. And a flat laminate 12 was obtained. The stack configuration is [45/0 / −45 / 90] _2S . The laminate 12 thus obtained was placed on a single-sided mold provided with a convex portion that shaped the final shape of the fiber-reinforced plastic after molding. A sealant was placed around the single-sided mold, and the bag film was covered to form a sealed space between the bag film and the single-sided mold. Attach a metal hose that accesses the sealed space and reduce the pressure with a vacuum pump. Then, the mold is carried into the autoclave, and the differential pressure between the sealed space and the autoclave atmosphere is 0.3 MPa at 150 ° C. for 2 hours. Then, autoclave molding was performed and the mold was removed to obtain a fiber reinforced plastic 16 as shown in FIG. 20c).

  The obtained fiber reinforced plastic 16 obtained good appearance quality and smoothness so as to be indistinguishable even when the surface quality was good and even the cut was made. Moreover, even if it cut out the cross section, since it pressurized with the autoclave, a void was not seen but it was estimated that high mechanical characteristics were expressed.

(Reference Example 1)
The fiber-reinforced plastic flat plate of Example 1 demonstrated that the fiber-reinforced plastic of Example 1 has high mechanical properties. A prepreg base material was prepared in the same manner as in Example 1, and a cut was introduced to prepare a cut prepreg base material. Each of the carbon fiber was cut into a size of 250 × 250 mm in the orientation direction of the carbon fiber (0 ° direction) and the direction shifted 45 degrees to the right from the orientation direction of the carbon fiber (45 ° direction). The cut prepreg base material was laminated in a pseudo isotropic manner with 16 layers ([45/0 / −45 / 90] _2S ) to obtain a laminate.

  Furthermore, after arrange | positioning in the approximate center part on the flat plate metal mold | die which has a cavity of 300x300mm using said laminated body, it is 150 degreeC x 30 minutes under the pressurization of 6 MPa with a heating type press molding machine. The plate was hardened under the above conditions to obtain a flat fiber reinforced plastic of 300 × 300 mm.

  A tensile strength test piece having a length of 250 ± 1 mm and a width of 25 ± 0.2 mm was cut out from the obtained flat fiber-reinforced plastic. According to the test method specified in JIS K-7073 (1998), the tensile strength was measured at a crosshead speed of 2.0 mm / min with a distance between the gauge points of 150 mm. In this reference example, an Instron (registered trademark) universal testing machine 4208 type was used as a testing machine. The number of test pieces measured was n = 5, and the average value was the tensile strength. Further, a standard deviation was calculated from the measured value, and the standard deviation was divided by an average value, thereby calculating a variation coefficient (CV value (%)) as an index of variation. The tensile elastic modulus was 43 GPa, the tensile strength was as high as 370 MPa, and the CV value was 3%, which was a very small variation.

  In the fiber reinforced plastic, the fibers are evenly flowed to the end, and like the first embodiment, a strip-like fiber bundle having a distribution with a fiber length Lc of 30 mm and a width Ws of about 11 to 15 mm is almost on the entire surface. Since it was evenly distributed, it was expected that the fiber reinforced plastic obtained in Example 1 would also exhibit high mechanical properties.

(Reference Example 2)
The fiber reinforced plastic of Example 3 demonstrated high mechanical properties with a fiber reinforced plastic flat plate. In the same manner as in Example 3, a two-layer laminate was obtained. From this two-layer laminate, cut into a size of 250 × 250 mm in each of a carbon fiber orientation direction (0 ° direction) and a direction shifted to the right by 45 degrees from the carbon fiber orientation direction (45 ° direction). A layer stack of 8 layers is laminated in a pseudo isotropic manner ([45/45/0/0 / -45 / -45 / 90/90] _S ) in each direction, and a 250 × 250 mm laminate having a notch on the entire surface. Got the body.

  The laminate thus obtained was hot press molded in the same manner as in Reference Example 1 to obtain a flat fiber reinforced plastic. The obtained fiber reinforced plastic was subjected to a tensile test in the same manner as in Reference Example 1. The tensile modulus was 46 GPa and the tensile strength was as high as 470 MPa, and the CV value was 4%, which was very small.

  In the fiber reinforced plastic, the fibers are flowing evenly to the end, almost no cut openings are seen on the surface, and the fiber direction is the same as in Example 3 in the state of rotation from the time when the laminate is arranged. For this reason, the fiber reinforced plastic obtained in Example 3 was also expected to exhibit high mechanical properties.

(Reference Example 3)
It was demonstrated on a flat plate that the fiber reinforced plastic of Example 4 has high mechanical properties. A cut prepreg base material was obtained in the same manner as in Example 4, cut out in the same manner as in Reference Example 1, laminated, and hot press molded. When the obtained fiber reinforced plastic was subjected to a tensile test in the same manner as in Reference Example 1, the tensile elastic modulus was 46 GPa, the tensile strength was as high as 620 MPa, and the CV value was 4%, which was a very small variation. . In fiber reinforced plastic, fibers flow evenly to the end, filling the cut openings while the fibers swell slightly, there are almost no cut openings on the surface, and even the cuts are indistinguishable Since the appearance is the same as in Example 4, it was expected that the fiber reinforced plastic obtained in Example 4 would also exhibit high mechanical properties.

(Comparative Example 1)
In the same manner as in Example 1, a fiber reinforced plastic having a plurality of double contour portions provided on a flat plate as shown in FIG. 15 was molded with a continuous fiber prepreg base material. In the same manner as in Example 1, a prepreg base material was produced. The thus obtained prepreg base material was cut into a rectangle (270 × 180 mm), and 16 layers were laminated in a [45/0 / −45 / 90] _2S laminated structure to obtain a plate-like laminate of 270 × 180 mm. Next, molding was performed in the same manner as in Example 1.

  It was found that the obtained fiber reinforced plastic could be easily removed from the mold, the surface was rough, and the fiber reinforced plastic was not completely adhered to the mold. The reason was presumed that the fibers were stretched and the laminate could not be stretched and did not conform to the mold.

(Comparative Example 2)
In the same manner as in Example 1, a fiber reinforced plastic having a plurality of double contour portions provided on a flat plate was molded using SMC as a laminate. 100 parts by weight of vinyl ester resin (manufactured by Dow Chemical Co., Ltd., Delaken 790) as a matrix resin of SMC, 1 part by weight of tert-butyl peroxybenzoate (manufactured by NOF Corporation, Perbutyl Z) as a curing agent, 2 parts by weight of zinc stearate (manufactured by Sakai Chemical Industry Co., Ltd., SZ-2000) is used as an internal mold release agent, and 4 parts by weight of magnesium oxide (Kyowa Chemical Industry Co., Ltd., MgO # 40) is used as a thickener. Then, they were sufficiently mixed and stirred to obtain a resin paste. The resin paste was applied onto a polypropylene release film using a doctor blade. From there, carbon fiber bundles (tensile strength 4,900 MPa, tensile elastic modulus 235 GPa, 12,000 fibers) cut to a length of 25 mm are uniformly dropped and dispersed so that the weight per unit area is 500 g / m ^2. did. Further, it was sandwiched between the other polypropylene film coated with the resin paste with the resin paste side inward. The volume content Vf of the carbon fiber with respect to the SMC sheet was 40%. The obtained sheet was allowed to stand at 40 ° C. for 24 hours, thereby sufficiently thickening the resin paste to obtain an SMC sheet. This SMC sheet was cut into a rectangle of 270 × 180 mm, and three sheets were laminated to obtain a laminate. Thereafter, molding was performed in the same manner as in Example 1 to obtain a fiber-reinforced plastic.

  In the obtained fiber reinforced plastic, fibers sufficiently flowed to the end of the cavity. Although there was no warp, some sink marks due to the density of the fibers were observed on the surface. Further, since Vf was 40%, it was estimated that the strength was not as high as that of Example 1.

It is a figure which shows an example of the manufacturing method of the fiber reinforced plastic of this invention. It is an enlarged plan view which shows an example of the cutting prepreg base material used for this invention. It is a top view which shows the example of the cutting prepreg base material used for this invention. It is the top view and sectional drawing which show an example of the laminated body used for this invention. It is sectional drawing which shows an example of the mechanism of the flow of the laminated body used for this invention. It is a top view which shows the example of the cutting positional relationship of the laminated body used for this invention. It is the top view and sectional view which show an example of the mode of extension of the layered product used for the present invention. It is an enlarged plan view which shows an example of the cutting prepreg base material used for this invention. It is an enlarged plan view which shows an example of the cutting prepreg base material used for this invention. It is a top view which shows the example of the cutting prepreg base material used for this invention. It is the top view and sectional view which show an example of the mode of extension of the layered product used for the present invention. It is a top view which shows an example of the mode of the expansion | extension of the laminated body used for this invention. It is the top view and sectional drawing which show an example of the manufacturing method of the fiber reinforced plastics of this invention. It is sectional drawing which shows an example of the manufacturing method of the fiber reinforced plastics of this invention. It is the schematic which shows an example of the fiber reinforced plastic manufactured by this invention. It is an enlarged plan view which shows an example of the cutting prepreg base material used for this invention. It is a top view which shows an example of the form of the cut prepreg base material used for this invention. It is the schematic which shows an example of the manufacturing method of the fiber reinforced plastics of this invention. It is sectional drawing which shows an example of the characteristic of the fiber reinforced plastic manufactured by this invention. It is the schematic which shows an example of the manufacturing method of the fiber reinforced plastics of this invention.

Explanation of symbols

1: Fiber longitudinal direction 2: Fiber orthogonal direction 3: Reinforcing fiber 4: Discontinuous end (cutting) of reinforcing fiber
4a: cut in layer a 4b: cut in layer b 4c (4c ₁ , 4c ₂ ): continuous cut 4d (4d ₁ , 4d ₂ ): intermittent cut 5: width cut into each other 6: in the fiber direction Distance L (fiber length L) between geometric centers of the pair of cuts
7: Row of intermittent notches 7a: Row of first intermittent cuts 7b: Row of second intermittent cuts 7c: Row of third intermittent cuts 7d: Fourth row of intermittent cuts 8: Geometric center of cut 8a: Geometric center of cut of layer a 8b: Geometric center of cut of layer b 9: Projected length Ws obtained by projecting the cut in the vertical direction of the reinforcing fiber
DESCRIPTION OF SYMBOLS 10: Cut prepreg base material 10a: Pre-preg base material with notches in the entire surface 10b: Pre-preg base material with notches in part 11: Pre-preg base material with continuous fiber base material 12: Laminate body 13: Laminate body 14: Flow of resin 15: Opening of end of reinforcing fiber 16: Fiber reinforced plastic 17: Short fiber layer 18: Area where no reinforcing fiber exists (cut opening)
19: Adjacent layer 20: Resin rich portion 21: Layer waviness 22: Fiber bundle end portion 23: Angle Θ formed by notch and fiber direction
24: Rotation of reinforcing fiber 25: Double contour part 26: Deaeration port 27: Spring 28: Mold 28a: Upper mold 28b: Lower mold 28c: Single-sided mold 28d: Split mold 29: Mold cavity 30: Sealed Space 31: Sealant 32: Stretchable film 33: Groove 34: Base material obtained by laminating two layers of cut prepreg base material 35: Area surrounded by two pairs of fiber bundle splitting portions (strip-shaped fiber bundle)
36: Area where continuous fibers are arranged 37: Area where only the cut prepreg base material in which the fibers are cut into a length of 10 to 100 mm by cutting is laminated (discontinuous part of the laminated body)
38: Vacuum drawing 39: Abutment position of prepreg base material 40: R section cross section 41: Layer whose depth is in the fiber orientation direction 42: Region where layer thickness is thick

Claims (13)

A method for producing a fiber reinforced plastic, wherein a laminate of a prepreg base material composed of reinforced fibers and a thermosetting resin aligned in one direction is hot press molded into a fiber reinforced plastic having a double contour portion. As the prepreg base material, at least the following (1) to (1), using a notched prepreg base material in which at least some of the reinforcing fibers are divided into a length of 10 to 100 mm by a plurality of cuts in a direction crossing the reinforcing fibers. A method for producing a fiber reinforced plastic, comprising sequentially molding the fiber reinforced plastic through the step (3).
(1) When a laminated body is obtained by laminating a plurality of prepreg base materials including the cut prepreg base material, at least a part of the laminated body is divided into 10 to 100 mm in length by reinforcing the cut. Lamination process (2) to obtain a flat laminate, placing the laminate on a mold and softening by heating so that a region where only the cut prepreg base material is laminated is formed. When the laminate is pressed against the mold and cured to form a fiber reinforced plastic, the region is disposed in the double contour portion of the mold, and the region is stretched and molded along the double contour portion. Molding step (3) Demolding step of taking out the fiber reinforced plastic from the mold A method for producing a fiber reinforced plastic, wherein a laminate of a prepreg base material composed of a reinforced fiber and a thermoplastic resin aligned in one direction is cold-pressed to obtain a fiber reinforced plastic having a double contour part, As the prepreg base material, at least the following (4) to (4) are used by using a cut prepreg base material in which at least some of the reinforcing fibers are divided into a length of 10 to 100 mm by a plurality of cuts in a direction across the reinforcing fibers. 6) A method for producing fiber reinforced plastic, wherein fiber reinforced plastic is molded sequentially through the process of 6).
(4) When a laminated body is obtained by laminating a plurality of prepreg base materials including the cut prepreg base material, at least a part of the laminated body is cut into lengths of 10 to 100 mm by the cutting to provide reinforcing fibers. Lamination process (5) to obtain a flat laminate by heating so as to form a region in which only the cut prepreg base material is laminated. The laminate is heated and softened at a lower temperature than the laminate. When the laminate is placed on a mold, and the laminate is pressed against the mold and solidified to form a fiber reinforced plastic, the region is placed in the double contour portion of the mold, and the region is expanded. (6) Demolding process for removing the fiber reinforced plastic from the mold All of the reinforced fiber which comprises the said cutting prepreg base material is divided | segmented by the said cutting, The fiber length L divided | segmented by the said cutting is in the range of 10-100 mm, The Claim 1 or 2 Manufacturing method for fiber reinforced plastic. The cut of the cut prepreg base material is linear, and the length W of the cut is 30 μm to 100 mm, and is intermittently and periodically disposed over the entire surface. The manufacturing method of the fiber reinforced plastic as described in 2. The notch prepreg base material is adjacent to two or more layers in succession, and any two adjacent layers of the two or more layers are arranged with respect to the geometric center of any notch on one notch prepreg base material and the other The manufacturing method of the fiber reinforced plastics in any one of Claims 1-4 laminated | stacked so that it may leave | separate 5 mm or more from the geometrical center of any notch on a notch prepreg base material. The manufacturing method of the fiber reinforced plastics in any one of Claims 1-5 in which the said notch inclines from the fiber orthogonal direction. The manufacturing method of the fiber reinforced plastics in any one of Claims 1-5 whose absolute value of angle (theta) which the said notch makes with a reinforced fiber is in the range of 2-25 degrees. The manufacturing method of the fiber reinforced plastics in any one of Claims 1-7 with which the said laminated body is comprised only from the said cut prepreg base material. The molding die is a single-sided die, the laminate is disposed on the single-sided die, the stretchable film is covered on the laminate and the laminate is sealed, and the sealed space and the outside air The manufacturing method of the fiber reinforced plastics in any one of Claims 1-8 which press and shape | mold the said laminated body to the said single-sided type | mold with a differential pressure. The mold comprises two or more molds, and continuous fibers are arranged in a region where the laminate first contacts both of the two molds when the laminate is pressed against the mold by clamping. Item 9. A method for producing a fiber-reinforced plastic according to any one of Items 1 to 8. After the said lamination process, prior to the said shaping | molding process, after pre-shaped the said laminated body to the substantially shape of the fiber reinforced plastic after shaping | molding, the said laminated body is arrange | positioned on a shaping | molding die. A method for producing the fiber-reinforced plastic according to claim 1. The manufacturing method of the fiber reinforced plastics of Claim 11 which pre-shapes the said laminated body to a single contour shape. In the uneven | corrugated | grooved part of a fiber reinforced plastic, the layer in which the reinforced fiber orientated in the angle of ± 10 degrees or less from the direction with the smallest curvature of the said uneven | corrugated | grooved part is thickened more thickly than another layer. Manufacturing method for fiber reinforced plastic.

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