JP2008207545A - Notched prepreg substrate, composite notched prepreg substrate, laminated substrate, fiber-reinforced plastic, and method for manufacturing notched prepreg substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prepreg substrate which has good fluidity and molding followability in a complex shape and develops excellent dynamics properties applicable to a structural material, the low dispersion of the properties, and high dimensional stability when made fiber-reinforced plastics and the laminated substrate of the prepreg substrate. <P>SOLUTION: The prepreg substrate 7 is composed of reinforcing fibers 3 arranged unidirectionally and a matrix resin and has notches 4 of angles Θ in relation to the reinforcing fibers whose absolute values are 2-25° on its entire surface. All the reinforcing fibers are divided substantially by the notches. The lengths L of the fibers range over 10-100 mm, the thickness H of the prepreg substrate over 30-300 μm, and the volume ratio Vf of the fibers over 45-65%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a prepreg base material that has good fluidity and molding followability, and exhibits excellent mechanical properties applicable to structural materials, its low variation, and excellent dimensional stability when it is made into a fiber reinforced plastic. And a manufacturing method thereof, and a laminated base material of the prepreg base material. About. More specifically, for example, the present invention relates to a prepreg base material that is an intermediate base material of fiber reinforced plastic suitably used for automobile members, sports equipment, and the like, a manufacturing method thereof, and a laminated base material of the prepreg base material.

  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 molding method of fiber reinforced plastic having high functional properties, a semi-cured intermediate base material impregnated with matrix resin is laminated on continuous reinforcing fiber called prepreg, and heated and pressurized in a high temperature and high pressure kettle. Autoclave molding in which a matrix 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 material previously shaped into a member shape is impregnated with a matrix 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, on the other hand, it is difficult to form a complicated shape such as a three-dimensional shape because it is a continuous fiber, and it is mainly limited to members close to a planar shape.

  As a molding method suitable for a complicated shape such as a three-dimensional shape, there is SMC (sheet molding compound) molding. SMC molding is performed by heating and pressurizing a semi-cured SMC sheet obtained by impregnating a chopped strand cut to about 25 mm with a matrix resin, which is a thermosetting resin, using a heating press. In many cases, before pressing, the SMC sheet is cut smaller than the shape of the molded body, placed on a mold, and stretched (flowed) into the shape of the molded body by pressing to perform molding. Therefore, it is possible to follow a complicated shape such as a three-dimensional shape by the flow. However, since SMC inevitably causes distribution unevenness and orientation unevenness of chopped strands in the sheeting process, the mechanical properties deteriorate or the variation of the values increases. Furthermore, due to uneven distribution and alignment unevenness of the chopped strands, warpage, sink marks and the like are likely to occur particularly in a thin member, which may be unsuitable as a structural material.

In order to fill the drawbacks of the above-described materials, a base material that can flow and reduce the variation in mechanical properties by cutting into a prepreg composed of continuous fibers and a thermoplastic resin is disclosed (for example, patents). References 1, 2). However, compared with SMC, the mechanical properties are greatly improved and the variation is small, but it cannot be said that the strength is sufficient for application as a structural material. Compared with the continuous fiber base material, since it has a configuration including a defect called a notch, the notch which is a stress concentration point becomes a starting point of fracture, and in particular, there is a problem that tensile strength and tensile fatigue strength are lowered.
Japanese Unexamined Patent Publication No. 63-247010 Japanese Patent Laid-Open No. 9-254227

  In view of the background of such prior art, the present invention has good fluidity, molding followability of complex shapes, and excellent mechanical properties applicable to structural materials when it is used as a fiber reinforced plastic, and its low variability. Another object of the present invention is to provide a prepreg base material that exhibits excellent dimensional stability, a manufacturing method thereof, and a laminated base material of the prepreg base material.

The present invention employs the following means in order to solve such problems. That is,
(1) A prepreg base material composed of a reinforced fiber and a matrix resin aligned in one direction, and an absolute value of an angle Θ between the prepreg base material and the reinforced fiber is 2 to 25 °. Having a cut, substantially all the reinforcing fibers are divided by the cut, the fiber length L of the reinforcing fiber divided by the cut is in the range of 10 to 100 mm, and the thickness H of the prepreg base material is A cut prepreg base material having a fiber volume content Vf in the range of 45 to 65%, which is 30 to 300 μm.

  (2) The cut prepreg base material according to (1), wherein the cut is linear.

  (3) The cut prepreg base material according to (1) or (2), wherein all of the reinforcing fibers divided by the cut have a substantially constant fiber length L.

  (4) The cut prepreg base material according to any one of (1) to (3), wherein the cuts are continuously made.

  (5) The incision is an intermittent incision in which a projection length Ws projected in the vertical direction of the reinforcing fiber is in a range of 30 μm to 100 mm, and the geometry of the incision and the incision adjacent to each other in the longitudinal direction of the fiber The cut prepreg base material according to any one of (1) to (3), which has the same shape.

  (6) The cut prepreg base material according to (5), wherein the projected length Ws is within a range of 30 μm to 1.5 mm.

  (7) The cut prepreg base material according to (5), wherein the projected length Ws is in the range of 1 to 100 mm.

  (8) The cut prepreg base material according to any one of (1) to (7), wherein the cut prepreg base material includes carbon fibers and a thermosetting resin.

  (9) The notch is provided obliquely in the thickness direction of the notched prepreg base material, and in any notch, a dividing line of reinforcing fibers on the upper surface of the notched prepreg base material and a dividing line on the lower surface When the distance in the fiber direction is S, the angle θ derived from the following (Formula 1) is in the range of 1 to 25 ° using the cut prepreg base material thickness H, (1) to (8 The cut prepreg base material according to any one of the above.

(10) The notch is provided so as not to penetrate the layers in the thickness direction from the upper surface and the lower surface of the notched prepreg base material, and the notch depth Hs is 0 with respect to the notched prepreg base material thickness H. In the range of 4H to 0.6H, the cut on the upper surface and the cut on the lower surface are cut in the range of 0.01H to 0.1H, respectively, and the angle formed by the arbitrary cut A on the upper surface and the fiber direction The cut prepreg according to any one of (1) to (8), wherein an angle Θb formed by the fiber direction of the cut B on the lower surface that intersects the cut A with respect to Θa is -Θa-5 ° to -Θa + 5 ° Base material.

  (11) The cut prepreg base material according to any one of (1) to (10) has a layered additional resin layer on at least one surface, and the thickness of the additional resin layer is equal to or greater than the short fiber diameter of the reinforcing fiber. And within the range of 0.5 times or less the thickness of the cut prepreg base material, the additional resin layer has a higher tensile elongation than the matrix resin, and the form is a film or nonwoven fabric. Cut prepreg base material.

  (12) On at least one surface of the cut prepreg base material according to any one of (1) to (10), an additional resin having a higher tensile elongation than the matrix resin is added to the cut prepreg base material thickness H. On the other hand, the additional resin is arranged in layers on the surface of the cut prepreg base material without entering the layer formed by the reinforcing fibers in the range of H to 100H in both directions of the fiber from the cut. A composite-cut prepreg base material in which the form is a film or a nonwoven fabric.

  (13) Two layers of the cut prepreg base material according to any one of (1) to (9) are laminated, and the crossing angle of the lower cut D that intersects the arbitrary cut C of the upper layer of the two-layer base is 4 Laminated substrate that is in the range of ~ 90 °.

  (14) A prepreg base material comprising the cut prepreg base material according to any one of (1) to (12) at least partially and including a reinforcing fiber aligned in one direction. Is a laminated base material in which a plurality of prepreg base materials, in which the reinforcing fibers are aligned in one direction, are integrated with the fiber directions of the prepreg base material oriented in at least two directions.

  (15) A laminated base material in which the laminated base material is composed only of the cut prepreg base material according to any one of (1) to (12), and the cut prepreg base material is laminated in a pseudo isotropic manner.

(16) A fiber-reinforced plastic obtained by molding the laminated substrate of (14) or (15).
(17) The layer in which the reinforcing fibers are substantially aligned in one direction is a fiber-reinforced plastic in which at least two layers are laminated in directions in which the reinforcing fibers have different orientations, and the fiber volume content Vf is 45 to 45. The layer constituting the fiber reinforced plastic has a notch opening portion formed of only the matrix resin or the reinforcing fiber of the adjacent layer without the presence of the reinforcing fiber as the layer constituting the fiber reinforced plastic. The fiber length L of the reinforcing fiber is divided within the range of 10 to 100 mm by the cut opening, and the surface area of the layer surface of the cut opening is within the range of 0.1 to 10% of the surface area of the layer. A fiber-reinforced plastic in which at least one short fiber layer having an average thickness Hc in the range of 15 to 300 μm is laminated.

  (18) The fiber reinforced plastic according to (16) or (17), wherein an area of an outermost layer of the fiber reinforced plastic is substantially zero.

  (19) A method for producing a cut prepreg substrate according to any one of (1) to (10), wherein a prepreg substrate is prepared by aligning reinforcing fibers in one direction and impregnating a matrix resin. The manufacturing method of the cutting prepreg base material which presses the rotary blade roller which has arrange | positioned the blade on the roller helically to a preliminary | backup prepreg base material, and makes a cut.

  (20) The method for producing a cut prepreg base material according to (9), wherein the reinforcing fibers are aligned in one direction and impregnated with a matrix resin to prepare a preliminary prepreg base material. A rotating blade roller having a blade arranged on the roller in a spiral shape is pressed from either the upper surface or the lower surface to make a cut that does not penetrate in the thickness direction of the layer of the cut prepreg base material, and then the rotating blade roller is A method for producing a cut prepreg base material, which is pressed from either the lower surface or the upper surface to make a cut that does not penetrate in the thickness direction of the layer in the thickness direction of the cut prepreg base material.

  (21) A method for producing a fiber-reinforced plastic having a multi-layered laminated structure composed of reinforcing fibers and a matrix resin, wherein the charge rate of the laminated base material of (14) or (15) is 50 to 95% A method for producing a fiber-reinforced plastic, which is pressure-molded within a range, and the area of the cut opening is substantially zero in the outermost layer.

  According to the present invention, it has good fluidity, molding conformability of complex shapes, and when it is made of fiber reinforced plastic, it has excellent mechanical properties applicable to structural materials, its low variation, and excellent dimensional stability. Can be obtained, a method for producing the same, and a laminated substrate of the prepreg substrate.

  The present inventors have excellent fluidity, molding followability of complicated shapes, and when used as a fiber reinforced plastic, a prepreg base material that exhibits excellent mechanical properties, low variation, and excellent dimensional stability. In order to obtain a prepreg base material, a specific cutting pattern is inserted into a specific base material called a prepreg base material composed of reinforcing fibers and a matrix resin aligned in one direction as the prepreg base material. It was clarified that these problems could be solved at once by laminating and pressure forming. In addition, the prepreg base material used in the present invention has a fiber sheet completely impregnated in the fiber 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 the resin. It includes a semi-impregnated resin base material (semi-preg: hereinafter, sometimes referred to as a semi-impregnated prepreg) integrated in a non-existing state.

  In the prepreg base material according to the present invention, since the reinforcing fibers are aligned in one direction, it is possible to design a molded body having arbitrary mechanical properties by controlling the orientation in the fiber direction. In the present specification, unless otherwise specified, in the term including fiber or fiber (for example, “fiber direction” or the like), the fiber represents a reinforcing fiber.

  Furthermore, the prepreg base material of the present invention is provided with cuts in the range of 2 to 25 ° in absolute value of the angle Θ formed with the reinforcing fibers on the entire surface, and substantially all the reinforcing fibers are divided by the cutting, The fiber length L divided by the cutting is in the range of 10 to 100 mm, the thickness H of the prepreg base material is 30 to 300 μm, and the fiber volume content Vf is in the range of 45 to 65%. In the present invention, “substantially all of the reinforcing fibers are divided by the incision” means that the area where the continuous fibers not divided by the incision of the present invention are aligned is a ratio of the prepreg base material area. Indicates less than 5%.

  In the present invention, the fiber length L refers to an incision (a pair of incisions that are the closest to the fiber direction in which an arbitrary incision and an incision equivalent to an arbitrary incision have a projected length Ws projected in the vertical direction of the reinforcing fiber This refers to the length of the fiber that is divided by the notch. Here, “projection length Ws in which the cut is projected in the vertical direction of the reinforcing fiber” means that, as shown in FIG. 2, the vertical direction of the reinforcing fiber (fiber orthogonal direction 2) is the projection plane and the projection is projected from the cut. It refers to the length when projected perpendicularly to the surface (fiber longitudinal direction 1). By making cuts on the entire surface of the prepreg base material and making the fiber length L of the reinforcing fibers in the base material all 100 mm or less, the fibers can flow at the time of molding, particularly in the longitudinal direction of the fiber. 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. When the fiber length L is less than 10 mm, the fluidity is further improved. However, even if other requirements are satisfied, the high mechanical properties necessary as a structural material cannot be obtained. Considering the relationship between fluidity and mechanical properties, it is more preferably in the range of 20 to 60 mm. There are fibers that are shorter than the fiber length L that is cut and divided in addition to the pair of cuts, but the fewer the fibers that are 10 mm or less, the better. More preferably, the area where the fibers of 10 mm or less are aligned is smaller than 5% of the ratio of the prepreg base material area.

  Even if the thickness H of the prepreg base material is larger than 300 μm, good fluidity can be obtained, but since the present invention has a cut, the larger the layer thickness to be divided, the lower the strength tends to be. If it is assumed to be applied to a structural material, it is necessary to set it to 300 μm or less. On the other hand, even if H is smaller than 30 μm, fluidity can be maintained and high strength can be obtained. However, since it is very difficult to stably produce an extremely thin prepreg base material, the effect of the present invention can be reduced at a low cost. It is necessary that the thickness is 30 μm or more. In view of the relationship between mechanical properties and cost, the thickness is preferably 50 to 150 μm.

  When the fiber volume content Vf is 65% or less, sufficient fluidity can be obtained. The lower the Vf, the better the fluidity. However, if Vf is less than 45%, the high mechanical properties required for the structural material cannot be obtained. Considering the relationship between fluidity and mechanical properties, it is more preferably in the range of 55-60%.

  Further, the notch is a major feature of the present invention that the absolute value of the angle Θ formed with the reinforcing fiber is in the range of 2 to 25 °. 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, if the absolute value of Θ is smaller than 2 °, sufficient fluidity and mechanical properties can be obtained, but it becomes difficult to make a stable cut. That is, when the incision lies on the fiber, the fiber easily escapes from the blade when making the incision, and in order to make the fiber length L 100 mm or less, the absolute value of Θ is less than 2 ° Production stability is lacking, for example, at least the shortest distance between the cuts is smaller than 0.9 mm. In addition, when the distance between the cuts is small as described above, there is 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 °. Hereinafter, unless otherwise specified, a prepreg base material having a cut on the entire surface of the present invention is referred to as a cut prepreg base material.

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

  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 incisions 4 that form pairs in the longitudinal direction of the fiber, and by setting the interval 6 to 10 to 100 mm, substantially all the reinforcing fibers on the prepreg base material have a fiber length L of 10 to 100 mm. be able to. Note that “substantially all of the reinforcing fibers are divided by the cutting” 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 shown in FIGS. 1 and 2, if the angle 5 between the cut and the reinforcing fiber is Θ, the absolute value of Θ is in the range of 2 to 25 ° over the entire surface. FIG. 3a) shows examples in which the absolute value of Θ is greater than 90 ° and b) is greater than 25 °. However, in these examples, the high strength obtainable by the present invention cannot be expressed.

  FIG. 4 shows a prepreg substrate having five different cut patterns. The prepreg substrate 7 of FIG. 4a) has skewed continuous, straight cuts 4 arranged at equal intervals. The prepreg substrate 7 of FIG. 4b) has skewed continuous, linear cuts arranged at two intervals. The prepreg substrate 7 of FIG. 4c) has continuous, curved (meandering) cuts 4 arranged at equal intervals. The prepreg substrate 7 of FIG. 4d) has intermittent linear cuts 4 that are arranged at equal intervals and are skewed in two different directions. The prepreg substrate 7 of FIG. 4e) has skewed intermittent linear cuts 4 arranged at equal intervals. The cut may be a curved line as shown in FIG. 4c), but a straight line as shown in FIGS. 4a), b), d), and e) is preferable because the flowability is easily controlled. In addition, the length L of the reinforcing fiber divided by the cut may not be constant as shown in FIG. 3b), but if the fiber length L is constant over the entire surface, the fluidity can be easily controlled and the strength variation can be reduced. Further, it can be pressed, which is preferable. Here, the prescribed linear shape means a state in which a part of a geometrical straight line is formed. However, as long as the effect of facilitating the fluidity control is not impaired, 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 more preferable example [1], it is preferable that the cuts 4a are continuously formed as shown in FIG. 1 and FIGS. 4a) to 4c). In the pattern of Example [1], since the cut 4a is not intermittent, flow disturbance does not occur in the vicinity of the cut end, and in the region where the cut 4a is made, all the fiber lengths L can be made constant, The flow is stable. Since the cuts 4a are continuously made, in order to prevent the cut prepreg base material 7 from falling apart, an area where the cut is not connected to the peripheral part of the cut prepreg base material is provided, or the cut is made. Handling property can be improved by gripping with a support such as a sheet-like release paper or a film that does not contain slag.

As another preferred example [2], as shown in FIG. 2, when the length 9 projected in the vertical direction of the reinforcing fiber is Ws, intermittent cuts 4b in which Ws is in the range of 30 μm to 100 mm are cut. The cut prepreg base material 7 is provided on the entire surface, and the cut 4b ₁ and the cut 4b ₂ adjacent to the cut 4b ₁ in the fiber longitudinal direction may have the same geometric shape. When Ws is 30 μm or less, it is difficult to control the cutting, and it is difficult to ensure that L is 10 to 100 mm over the entire surface of the cut prepreg substrate. That is, when there is a fiber that is not cut by cutting, the fluidity of the base material is remarkably lowered, but there is a problem that a portion where L is less than 10 mm appears when a large amount of cutting is made. Conversely, when Ws is greater than 10 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. FIG. 2 shows an example in which both L and Ws are one type. Any of the cuts 4b (for example, 4b ₁ ) has another cut 4b (for example, 4b ₂ ) that is overlapped by translation in the fiber direction. The fiber length is stable by the presence of a width 8 in which the fibers are divided by adjacent cuts at a fiber length shorter than the fiber length L divided by the cuts 4b that form a pair in the fiber direction. The cut prepreg base material 7 can be manufactured at 100 mm or less. In the pattern of Example [2], when the obtained cut prepreg base material 7 is laminated, since the cut is intermittent, the handleability is excellent. Although other patterns are illustrated in FIGS. 2d) and e), any pattern may be used as long as the above conditions are satisfied.

  In the preferred example [2], the length Ws projected in the vertical direction of the reinforcing fiber is preferably in the range of 30 μm to 1.5 mm from the viewpoint of mechanical properties. Since the projection length Ws can be reduced with respect to the cut length when the absolute value of the cut angle Θ is 2 to 25 °, a minimum cut of 1.5 mm or less is industrially stable. Can be provided. By reducing Ws, the amount of fibers cut by each cutting is reduced, and strength improvement is expected. In particular, when Ws is 1.5 mm or less, a great improvement in strength is expected. Further, from the viewpoint of processability, preferably, by setting Ws within a range of 1 mm to 100 mm, it is possible to insert the cut with a simple device.

  A plurality of prepreg base materials in which reinforcing fibers are aligned in one direction, including at least the incised prepreg base material thus obtained, are laminated, and the fiber directions are oriented in at least two directions and laminated together. The molded fiber reinforced plastic has the following characteristics at the site where the cut prepreg substrate is applied. The layer in which the reinforcing fibers are substantially aligned in one direction is a fiber reinforced plastic obtained by laminating at least two layers in different directions of the reinforcing fibers, and the fiber volume content Vf is 45 to 65%. A plurality of slit openings formed on the entire surface of the layer without the presence of reinforcing fibers and formed only of the matrix resin or the reinforcing fibers of the adjacent layer, The fiber length L of the reinforcing fiber is divided within the range of 10 to 100 mm by the cut opening, the surface area of the cut opening at the layer surface is within the range of 0.1 to 10% of the surface area of the layer, and the average thickness At least one short fiber layer having a Hc in the range of 15 to 300 μm is laminated. That is, the greatest feature of the present invention is that the end portion of the fiber bundle due to the cut made by the cut prepreg base material does not open by molding. In the present invention, “substantially aligned in one direction” means that 90% or more of the fiber group existing within a radius of 5 mm is not less than the arbitrary fiber when attention is paid to a certain part of the arbitrary fiber. It is oriented within ± 10 ° from some fiber angles.

  This feature will be described with reference to FIGS. As a comparison of the present invention, FIG. 5 shows a laminated body 10 in which a cut prepreg base material 7 in which the absolute value of the angle Θ between the cut 4 and the fiber 3 is 90 ° is laminated a), and the laminated body 10 is molded. The fiber reinforced plastic 11 b) is a plan view showing a close-up of the layer derived from the cut prepreg base material 7 and a cross-sectional view taken along the line AA of the plan view. As shown in a), the cut prepreg base material 7 is provided with a cut perpendicular to the fiber on the entire surface, and the cut 4 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 11 whose area is easily extended from the laminate 10 can be easily obtained by press molding or the like (however, the thickness is reduced). When the elongated fiber reinforced plastic 11 is obtained as in b), the short fiber layer 12 derived from the cut prepreg base material 7 extends in the fiber vertical direction and has no fiber (cut opening) 13. Is generated. This is because the reinforcing fibers generally do not expand at a molding level pressure. In the case of FIG. 5, the cut opening 13 is generated for the extended length, for example, 250 × 250 mm laminated substrates 10 to 300 are formed. When the fiber reinforced plastic 11 of × 300 mm was obtained, the total area of the cut openings 13 was 50 × 300 mm, that is, 1/6 (about 16.7%) with respect to the surface area of the fiber reinforced plastic 11 of 300 × 300 mm. ) Is a calculation for a cut opening. As shown in the cross-sectional view, the region 13 is occupied by the substantially triangular resin-rich portion 16 and the region in which the adjacent layer has intruded. Therefore, when the laminated body 10 using the cut prepreg base material 7 is stretched and formed, the undulation 17 of the layer and the resin rich portion 16 are generated at the fiber bundle end portion 15, which causes deterioration of mechanical properties and surface quality. Affects decline. In addition, since the rigidity is different between the part where the fiber is present and the part where the fiber is not present, the fiber-reinforced plastic 11 has in-plane anisotropy. Further, in terms of strength, the fiber oriented to about ± 10 ° or less from the load direction transmits most of the load, but the fiber bundle end 15 must redistribute the load to the adjacent layer 14. Don't be. At that time, as shown in FIG. 5b), when the fiber bundle end 15 is perpendicular to the load direction, stress concentration is likely to occur, and peeling is also likely to occur. Therefore, the strength improvement cannot be expected so much.

  On the other hand, FIG. 6 shows a laminate 10 in which the cut prepreg base material 7 of the preferred example [1] of the present invention is laminated in a), and a fiber reinforced plastic 11 in which the laminate 10 is molded in b). The top view which closed the layer derived from the embedded prepreg base material 7, and the sectional view which cut out the AA cross section of the top view were shown. As shown in a), the cut prepreg base material 7 is provided with continuous cuts 4a having an absolute value of the angle Θ between the fibers 3 of 25 ° or less, and the cuts 4a penetrate through the thickness direction of the layers. Yes. By setting the fiber length L to 100 mm or less, the fluidity is ensured, and the fiber reinforced plastic 11 whose area is easily extended from the laminate 7 can be obtained by press molding or the like. When the stretched fiber reinforced plastic 11 is obtained as in b), the short fiber layer 12 derived from the cut prepreg base material 7 stretches in the fiber vertical direction, and the fiber 3 itself rotates 18 to expand the stretched region. In order to earn an area, a region (incision opening) 13 in which no fiber exists as shown in FIG. It is within the range of 10%. Therefore, as can be seen from the cross-sectional view, the adjacent layer 14 does not penetrate, and the high-strength and high-quality fiber-reinforced plastic 11 having no layer waviness or 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 revolutionary effect that this fiber rotates and stretches to obtain a fiber reinforced plastic without layer waviness is that the absolute value of the angle Θ between the cut and the reinforcing fiber is 25 ° or less, and the cut is continuous. It can be obtained only by being put in. 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 15 lies down with respect to the load direction as shown in FIG. I can see the situation. Since the fiber bundle end portion 15 is slanted in the layer thickness direction, the load is smoothly transmitted, and peeling from the fiber bundle end portion 15 hardly occurs. Therefore, a marked improvement in strength is expected compared to FIG. The fiber bundle end 15 is inclined in the layer thickness direction because when the above-described fiber rotates, there is a gentle distribution in the rotation 18 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 15 is inclined in the layer thickness direction. In such a layer of the fiber reinforced plastic 11, a fiber bundle end portion that is slanted in the layer thickness direction is formed, and the epoch-making effect of remarkably improving the strength is that the absolute value of the angle Θ formed with the fiber 3 of the cut 4 a is 25 °. It can be obtained for the first time by the following.

  In FIG. 7, the laminated body 10 in which the cut prepreg base material 7 of the preferred example [2] of the present invention is laminated is shown in a), and the fiber reinforced plastic 11 in which the laminated body 10 is molded is shown in b). The top view which closed up the layer derived from the base material 7 was shown. As shown in a), the cut prepreg base material 7 is provided with intermittent cuts 4b having an absolute value of the angle Θ between the fibers 3 of 25 ° or less, and the cuts 4b penetrate the layer thickness direction. ing. The fiber length L is set to 100 mm or less over the entire surface of the cut prepreg base material 7 by the cuts 4b, so that the fluidity is ensured, and the fiber reinforced plastic 11 whose area is easily extended from the laminate 7 by press molding or the like. Obtainable. 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 11 is obtained as in b), the short fiber layer 12 derived from the cut prepreg base material 7 does not stretch in the fiber direction when stretched in the fiber vertical direction. A non-existing region (cut opening) 13 is generated, but the adjacent short fiber group flows in the fiber vertical direction, thereby filling the cut opening 13 and reducing the area of the cut opening 13. This tendency is particularly noticeable 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 13 is not substantially generated, and the surface of the layer of the cut opening is formed. In the range of 0.1 to 10% compared to the surface area of the layer. Therefore, it is possible to obtain a high-strength and high-quality fiber-reinforced plastic 11 without layer undulation or resin-rich portion without adjacent layers intruding in the thickness direction. 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 with a flow in the vertical direction of the fiber to obtain a fiber reinforced plastic having no layer waviness has an absolute value of the cut angle Θ of 25 ° or less and the cut is formed in the vertical direction of the reinforcing fiber. It can be obtained for the first time when the projected length Ws is 1.5 mm or less. More preferably, when Ws is 1 mm or less, higher strength and higher quality can be achieved.

  More preferably, in the outermost layer of the fiber reinforced plastic, the area of the cut opening is substantially zero. It should be noted that the area of the cut opening is “substantially 0”, it is desirable that no opening exists, but the area of the cut opening in the outermost layer is 1% or less compared to the surface area of the fiber reinforced plastic. It means no problem. If the absolute value of Θ is larger than 25 °, a region where there is no fiber in the resin-rich part or its layer, that is, a region where the reinforcing fiber of the adjacent layer is viewed is generated in the outermost layer. Is difficult. On the other hand, in the present invention, it is difficult to generate a resin-rich portion or a region without fibers, so that it can be applied as an outer plate member.

  Examples of the reinforcing fiber used in the cut prepreg base material of the present invention include organic fibers such as aramid fiber, polyethylene fiber, polyparaphenylene benzoxador (PBO) fiber, glass fiber, carbon fiber, silicon carbide fiber, and alumina. Examples thereof include inorganic fibers such as fibers, Tyranno fibers, basalt fibers, and ceramic fibers, metal fibers such as stainless fibers and steel fibers, and reinforcing fibers that use boron fibers, natural fibers, modified natural fibers, and the like as fibers. 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 notched prepreg base material of the present invention include, for example, epoxy resins, unsaturated polyester resins, vinyl ester resins, phenol resins, epoxy acrylate resins, urethane acrylate resins, phenoxy resins, alkyd resins, urethane resins, 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), polyether ether ketone (PEEK), liquid crystal polymer, vinyl chloride, polytetrafluoroethylene and other fluororesins, silicone and other thermoplastic resins It is below. 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. On the other hand, in the case of a thermoplastic resin prepreg base material that does not have tack at room temperature, the base materials slip when the prepreg base materials are laminated. It becomes reinforced plastic. In particular, when molding with a mold having an uneven portion, the difference appears remarkably.

  Furthermore, since the incised prepreg base material of the present invention composed of a thermosetting resin has excellent drapability at room temperature, for example, when molding using a mold having an uneven portion, the uneven portion is preliminarily aligned with the unevenness. Pre-shaping can be easily performed. This pre-shaping improves moldability and facilitates flow control.

  Moreover, the cut prepreg base material of 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 “Teflon (registered trademark)” type release agent, metal vapor deposition, or the like may be applied to the surface.

  More preferably, among the 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 satisfying the present invention is obtained. Can do. Among them, the epoxy resin is most excellent in mechanical properties as a reinforced fiber composite material obtained in combination with carbon fiber.

  In such a matrix resin, the temperature T at which the thermosetting resin can be cured within 10 minutes is within the range of (Tp-60) to (Tp + 20), where Tp is an exothermic peak temperature due to DSC of the thermosetting resin. It is preferable that it exists in. Here, being able to cure means that the molding precursor containing the thermosetting resin can be taken out in a state in which the shape of the molding precursor is maintained after being held for a certain time at a certain temperature. As an evaluation method, 1.5 ml of a thermosetting resin was injected into a polytetrafluoroethylene O-ring having an inner diameter of 31.7 mm and a thickness of 3.3 mm placed on a heated press, and heated and pressurized for 10 minutes for crosslinking. This means that the resin test piece can be taken out without being deformed after the reaction has proceeded. When the temperature T at which the thermosetting resin can be cured within 10 minutes is lower than (Tp-60) ° C., it takes time to raise the temperature at the time of molding, so the molding conditions are limited, and from (Tp + 20) ° C. If it is high, there is a possibility that voids are generated inside the resin due to an abrupt reaction of the resin, resulting in poor curing. In addition, exothermic peak temperature Tp based on DSC in this invention is taken as the value measured on temperature rising conditions 10 degree-C / min conditions.

  Examples of the thermosetting resin exhibiting the above curing characteristics include compounds having at least an epoxy resin, a curing agent being an amine curing agent, and a curing accelerator having two or more urea bonds in one molecule. Specifically, 2,4-toluenebis (dimethylurea) or 4,4-methylenebis (phenyldimethylurea) is preferable as the curing accelerator.

  As a method of cutting into the prepreg base material to obtain the incised prepreg base material of the present invention, first, a prepreg base material of continuous fibers aligned in one direction is prepared, and then manual work using a cutter or In a method of cutting with a cutting machine, or in a prepreg manufacturing process of continuous fibers aligned in one direction, a rotating roller with blades arranged at predetermined positions is continuously pressed, or a plurality of prepreg base materials are stacked in layers. There is a method of pushing and cutting with a mold in which a blade is arranged at the position of. The former is suitable when the prepreg base material is simply cut, and the latter is suitable when producing a large amount in consideration of production efficiency. In the present invention, since the cutting angle is small, the amount of fibers to be cut per unit length of the blade is reduced, and the fibers can be cut with a small force, so that the remaining amount of fibers is reduced and the durability of the blade is improved. it can. 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).

  In particular, as shown in FIG. 8, a production method in which a rotary blade roller 19 provided with a spiral blade 20 is pressed to make a cut is excellent in production stability. Here, the spiral blade may be a continuous blade or an intermittent blade, and a continuous cut as shown in FIG. 1 and an intermittent cut as shown in FIG. 2 can be inserted respectively. In addition, as shown in FIG. 9, after the fibers are arranged obliquely, a cut may be inserted in the longitudinal direction 33 or the width direction 34 of the prepreg base material. For example, as shown in FIG. 9 a), the prepreg base material and the tape-shaped prepreg base material (or fiber bundle) are arranged so that the direction inclined by 2 to 25 ° from the longitudinal direction 33 of the prepreg base material is the fiber direction, and the moving head 31 is moved. It may be used to align (after passing through the impregnation step in the case of a fiber bundle) and press the pressing blade 29 for inserting a cut in the longitudinal direction of the prepreg substrate. Cutting may be performed using a rotating roller instead of the press cutting blade 29. For example, as shown in FIG. 9b), the prepreg base material and the tape-shaped prepreg base material (or fiber bundle) are moved to a moving head so that the direction inclined by 2 to 25 ° from the width direction 34 of the prepreg base material is the fiber direction. Rotating blade 32 that inserts continuously or intermittently in the width direction of the prepreg base material may be pressed using 31 (after passing through an impregnation step in the case of a fiber bundle). In addition, after the cut is made, the cut prepreg base material is further thermocompression bonded with a roller or the like, so that the resin is filled and fused in the cut portion, thereby improving the handleability.

  More preferably, as shown in FIG. 10, two layers of the cut prepreg substrate 7 of the present invention are laminated, and the crossing angle (absolute value) of the lower cut D (4d) intersecting with the upper cut C (4c) is 4. It is better to use a two-layer substrate that is in the range of ~ 90 °. The cut prepreg base material of the present invention has an absolute value of the cut angle Θ relative to the fiber of 25 ° or less and the fiber length L must be 100 mm or less, so that the cut amount per unit area is geometrically large. Become. Therefore, the cut prepreg base material is inferior in handleability because the fiber is divided everywhere. In particular, when the cuts are continuously made, the handleability is remarkably reduced. Accordingly, by stacking two layers of the cut prepreg base material having the same cut angle with a machine or the like in advance, the handleability is remarkably improved at the time of multilayer lamination. Three or more layers may be laminated. However, since the drape property is lowered by increasing the thickness, it is preferable to treat the two-layer laminated substrate as one unit. The combination of the upper layer and the lower layer of the two-layer base material may be a combination of notched prepreg base materials having any fiber orientation as long as the angle between the cuts is 4 to 90 °. For example, 45 ° and −45 °, 0 ° and 90 °, 0 ° and 0 °, etc. are preferable.

  As shown in FIG. 11, the cut prepreg base material of the present invention is more preferably provided with a cut 4e that does not penetrate from the top surface and the bottom surface of the cut prepreg base material in the thickness direction of the layer. Depth Hs is in the range of 0.4H to 0.6H with respect to the cut prepreg base material thickness H (22), and the cuts on the upper surface and the lower surface are in the range of 0.01H to 0.1H, respectively. The angle Θb formed by the fiber direction of the lower notch B intersecting the notch A is −Θa with respect to the angle Θa formed by the inner notch (23) and an arbitrary notch A on the upper surface and the fiber direction. A cut prepreg base material 7 is preferable. Although the strength tends to decrease as the depth of cut increases, there is a limit to how thin the prepreg can be made at a low cost, so the upper and lower surfaces should be cut at a depth that is approximately half the thickness of the prepreg substrate at the time of cutting. It was found that by adding it from the inside, the strength can be greatly improved and the fluidity can be secured. In addition, a thin cut prepreg base material may be prepared and pasted, but considering the cost improvement of the pasting process, this method of cutting from both sides is preferable. The angle Θb is preferably −Θa as described above. However, the effect that the strength can be greatly improved and the fluidity can be ensured is not impaired. Θb = −Θa−5 ° to − If it is within the range of Θa + 5 °, there is no problem. FIG. 11 shows the case where the depth of the cut U entering the upper surface of the cut prepreg base material is the same as the depth of the cut D entering the lower surface, but the depth of cut H of U is Hs. , U and the depth of cut Hs, d of D are different from each other as long as they are within the range of 0.4H to 0.6H.

  The angles Θa and Θb formed by the fiber directions of the cut A on the upper surface and the cut B on the lower surface of the cut prepreg base material are preferably in a relationship of Θa = −Θb. Since the degree of strength improvement varies depending on the angle of cut, the absolute value of Θ is the same, so that a cut prepreg substrate with stable performance can be obtained. In addition, since the direction in which the fiber rotates during molding is determined by the sign of the angle of cut, the average fiber orientation can be made the fiber direction during lamination by reversing the direction of fiber rotation, resulting in robustness. It becomes an excellent base material.

  Although the cutting depth Hs is ideally 0.5H, by making the size of the defects uniform, the fracture start load can be minimized by minimizing the size of the contained defects. If there is a fiber that is not divided by the incision from the upper surface and the incision from the lower surface, the fluidity is remarkably lowered. Therefore, the quality that lowers the fluidity by making an incision of about 0.5H + 0.05H from the upper and lower surfaces. Production stability can be secured without defects.

  As means for realizing the above incision, for example, a prepreg base material in which reinforcing fibers are aligned in one direction is prepared, and an incision that does not penetrate in the thickness direction of the layer from either the upper surface or the lower surface is pressed. There is a method of pressing the stamp on the other side after pressing the stamp. In particular, it is excellent in production stability to press a rotating blade roller with a spiral blade disposed on the roller from one side and make a cut that does not penetrate the thickness direction of the layer, and then press the spiral roller from the other surface. ing.

  More preferably, as shown in FIG. 12, the cut 4f is provided obliquely in the thickness direction of the cut prepreg base material, and at any cut, the cut line of the reinforcing fiber on the top surface of the cut prepreg base material and the bottom surface When the distance 24 in the fiber direction from the dividing line is the shear distance S, the angle θ (26) derived from the following equation 1 using the cut prepreg base material thickness H (22) is in the range of 1 to 25 °. The cut prepreg base material 7 inside is good.

  As described above, the fiber bundle end portion of the fiber reinforced plastic obtained by laminating and molding the cut prepreg base material in which the absolute value of the angle Θ between the cut and the fiber direction is 25 ° or less in the plane is in the layer thickness direction. This greatly contributes to the improvement of strength. Therefore, by making oblique cuts in the depth direction at the stage of the cut prepreg base material, the above effect is further assisted, and the angle of the fiber bundle end when made into fiber reinforced plastic is further reduced to improve strength. I was able to contribute. In particular, when the cutting angle θ is 25 ° or less, the effect of improving the mechanical characteristics is remarkable. On the other hand, when θ is smaller than 1 °, it is very difficult to provide an oblique cut.

  As a means for realizing the above incision, there is also a method of making an incision directly obliquely.For example, a prepreg base material in which reinforcing fibers are aligned in one direction is prepared, and an incision penetrating the thickness direction of the layer is performed. After insertion, press the nip rollers with different rotation speeds on the upper and lower surfaces while the cut prepreg base material is heated and softened, and the shearing force makes the cross section of the reinforcing fibers slant in the thickness direction, etc. There is also a method. In the latter case, in the cross-section cut perpendicularly to the outside direction of the cut prepreg base material where the side surface portion of the reinforcing fiber can be seen, the fiber breaking line due to the cut is not linear but rattle, but for the sake of convenience. The distance 24 in the fiber direction between the cut on the upper surface of the cut prepreg substrate and the cut on the lower surface of the cut prepreg substrate is used as the shear distance S. The average of the shear distances 24 of the respective cuts 4f on the entire surface of the cut prepreg base material is substituted into Equation 1 as S to obtain the cut angle θ.

  Furthermore, at least one surface of the above-mentioned cut prepreg base material has a tensile elongation higher than that of the matrix resin in the cut prepreg base material and is not less than the short fiber diameter of the reinforcing fiber, and the thickness of the cut prepreg base material A composite-cut prepreg base material provided with a layered additional resin layer having a thickness in the range of 0.5 times or less of the above and having a film-like or non-woven fabric form may be used. The fiber reinforced plastic obtained by laminating and molding the cut prepreg base material of the present invention has a final elongation when cracks generated from within the layers are connected by delamination, so an additional resin layer having a high elongation is provided between the layers. This dramatically reduces delamination and improves strength.

  More preferably, as shown in FIG. 13, the cut prepreg base material thickness H (22) having a tensile strength higher than that of the matrix resin in the cut prepreg base material on at least one surface of the cut prepreg base material 7 described above. In the range of H to 100H in both directions from the cut to the fiber direction, the film or nonwoven fabric is arranged in layers on the cut prepreg substrate surface without entering the layer formed by the reinforcing fibers A composite cut prepreg base material provided with an additional resin 28 is preferable. As used herein, “both directions in the fiber direction” means a left direction and a right direction along the fiber direction 1 with the notch 4 as a boundary, as shown in FIG. As described above, since the tensile elongation of the additional resin is larger than that of the matrix resin, delamination hardly occurs. On the other hand, when the additional resin is excessive, the fiber volume content Vf of the fiber reinforced plastic is decreased and the elastic modulus is decreased. Will tend to decline. Therefore, it is preferable that the amount of additional resin applied is less than 10% of the matrix resin. Strengthening is expected with high efficiency by arranging additional resin concentrated on the fiber bundle end where stress concentration is likely to occur. Moreover, about the method of arrangement | positioning of an additional resin, it is good not to enter in the layer which a reinforced fiber forms, but to arrange | position in layers on the cut prepreg base material surface. The inside of the layer formed by the reinforcing fibers refers to a cut prepreg base material obtained by impregnating the reinforcing fibers in which the matrix resin is previously aligned in one direction. If the additional resin is arranged so as to rise greatly from the cut prepreg base material, it is not preferable because it becomes bulky at the time of lamination. It is preferable that the additional resin is processed into a film or a nonwoven fabric in advance and arranged in layers so as to cover the cuts. At this time, the thickness of the additional resin is preferably larger than the reinforcing fiber single yarn and smaller than half of the layer thickness H. Here, the additional resin is arranged in a layer form without entering the layer formed by the reinforcing fibers, and the additional resin is arranged in a mode in which an anchor effect is obtained in the layer formed by the reinforcing fibers. This means that a small amount of additional resin (for example, 20% by volume or less of the total additional resin) has entered the layer formed by the reinforcing fibers by melting or the like (that is, some reinforcing fibers) ) May be present in the presence of 20% or less by volume of the total additional resin instead of the matrix resin.

The tensile elongation of the additional resin may be anything as long as it is larger than that of the matrix resin, but is preferably 2 to 10 times, and preferably within a range of 2 to 50%. More preferably, it is in the range of 8 to 20%. Since the tensile elongation is greater than that of the additional resin, delamination is less likely to occur and strength improvement is expected. Further, the tensile strength of the additional resin is preferably larger than that of the matrix resin. That is, the higher the tensile strength, the less likely the cracks, which are resin cracks, occur, the better the additional resin has strength than the matrix resin. More preferably, it has a strength of 1.5 times or more. The tensile elongation and tensile strength of the resin are measured according to JIS K7113 (1995) or ASTM D638 (1997). More preferably, the fracture toughness value of the additional resin is larger than that of the matrix resin. The fracture toughness value of the resin is measured by, for example, ASTM E399 (1983) (compact test standard), but the value varies greatly depending on the measurement method. Therefore, the fracture toughness value when compared in the same test is, for example, 100 J / matrix resin. added to m ² resin such as 500 J / ^{m 2,,} better larger as compared with the matrix resin. More preferably, it should be at least three times the fracture toughness value of the matrix resin.

  As the additional resin, any resin may be used as long as it has a higher tensile elongation than the resin used as the matrix resin from the group of resins applied to the matrix resin described above, and a thermoplastic resin is particularly preferable. It is known that the resin elongation and fracture toughness are higher than those of a general thermosetting resin, and the strength improvement effect of the present invention is effectively achieved. Furthermore, polyamide, polyester, polyolefin, and polyphenylene sulfone are preferable in terms of the balance between resin characteristics and cost and the degree of freedom in designing the resin viscosity. As the additional resin has higher compatibility with the matrix resin, the effect of the present invention is exhibited. Therefore, it is preferable that the additional resin has a melting point equal to or lower than the molding temperature. In particular, a polyamide having a low melting point of about 100 to 200 ° by copolymerization or the like is excellent in compatibility with a thermosetting resin, and has a high tensile tensile strength, tensile strength, and fracture toughness, and is preferable. When carbon fiber is used as the reinforcing fiber, epoxy resin is used as the matrix resin, and polyamide resin is used as the additional resin, the most lightweight, high-strength, high-rigidity fiber-reinforced plastic can be obtained.

  The laminated base material of the present invention is a laminated base material having at least a part of the cut prepreg base material, and a plurality of prepreg base materials in which reinforcing fibers are aligned in one direction are laminated, The prepreg base material in which the reinforcing fibers are aligned in one direction is preferably a laminated base material in which the fiber directions are aligned in at least two directions and integrated. For example, hybrid lamination may be carried out using a prepreg base material that is a cut prepreg base material and a unidirectional base material without a cut or a woven base material. Moreover, the whole surface may be comprised with the cutting prepreg base material.

  The cut prepreg base material of the present invention flows only in the fiber vertical direction with only one layer. That is, since the flow of the resin in the 90 ° direction is a driving force for moving the fiber, the fluidity is manifested only when two or more layers are laminated in different fiber directions. Preferably, the layer adjacent to the cut prepreg substrate of the present invention is a prepreg substrate (including the cut prepreg substrate of the present invention) in which reinforcing fibers are oriented in one direction, and is different from the cut prepreg substrate. It is good to be laminated in the fiber direction. 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. Moreover, the continuous fiber base material can be arranged in the site | part which does not need to flow, and also the mechanical characteristic of the site | part can be improved. Depending on the shape, the unidirectional prepreg base material having no cut and the cut prepreg base material of the present invention can be laminated and used. For example, in the case of a cylindrical body having a uniform cross-sectional shape, there is no problem in fluidity even if continuous fibers are arranged in a direction where there is no change in shape.

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 laminated base material of 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 laminated base material of the present invention is characterized in that high fluidity can be exhibited even with a high Vf configuration capable of improving mechanical properties. In addition, if the resin viscosity at the time of molding is 1 × 10 ⁴ Pa · s or less, fluidity may be excellent, but if it is less than 0.01 Pa · s, the resin cannot efficiently transmit force to the fiber, May not be suitable.

More preferably, it is a laminated base material made of only the cut prepreg base material of the present invention and laminated in a pseudo isotropic manner. By using only the cut prepreg base material of the present invention, air trapped at the time of lamination is easily degassed by cutting in the thickness direction, voids are hardly generated, and high mechanical properties can be expected. Of these, isotropic lamination such as [+ 45/0 / −45 / 90] _S and [0 / ± 60] _S is preferable in order to achieve uniform physical properties and suppress the generation of warpage. In addition, since the flow of the resin in the 90 ° direction is a driving force for moving the fiber as described above, the flow of the fiber differs depending on the fiber orientation of the adjacent layer, but the fluidity becomes isotropic by using the pseudo isotropic lamination, It becomes a molding material with less fluidity variation and excellent robustness.

  The fiber-reinforced plastic of the present invention is preferably obtained by curing the laminated base material. Examples of the curing method, that is, the method of molding the fiber reinforced plastic include press molding, autoclave molding, sheet winding molding and the like. Of these, press molding is preferable in consideration of production efficiency. More preferably, the laminated base material of the present invention is pressure-molded within the range of 50 to 95% of the charge rate, and the matrix resin or the adjacent layer is reinforced without the outermost layer reinforcing fiber in the cut portion of the outermost layer. A manufacturing method for obtaining a fiber-reinforced plastic having a good appearance quality by setting the area of the cut opening formed of only fibers to substantially zero is preferable.

  In the laminated base material, the assembly cost can be reduced by embedding, hardening, and integrating the metal insert in order to provide a mechanism such as a rotating part in a portion where only the cut prepreg base material of the present invention is laminated. 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.

  In addition, the cut prepreg base material of the present invention and fiber-reinforced plastic using the same are used for shafts and heads, doors and seats of sports parts such as bicycle equipment and golf, which require strength, rigidity and light weight. There are automotive parts such as frames and mechanical parts such as robot arms. In particular, the present invention can be preferably applied to automobile parts such as seat panels and seat frames that require molding followability of complicated shapes in addition to strength and light weight.

  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.

<Flat plate forming method>
After a predetermined base material is placed on a 300 × 300 mm mold, it is fluidized and molded in a temperature atmosphere of 150 ° C. under a pressure of 6 MPa by a heating press molding machine for a predetermined time, and a 300 × 300 mm flat plate A shaped molded body was obtained.

<Mechanical property evaluation method>
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 molded body. 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 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.

<Formability evaluation>
The fluidity and warpage were evaluated from the properties of the obtained flat plate-shaped body.
In terms of fluidity, when the base material is stretched and molded, fiber reinforced plastic is filled in the mold cavity, and the base material placed on the outermost layer also extends to the vicinity of the mold edge. Is fluidity ○, but fiber reinforced plastic is filled in the mold cavity, but when the base material arranged on the outermost layer is not stretched, fluidity △, fiber reinforced plastic is in the mold cavity. When there was an unfilled part, it evaluated as fluidity | liquidity x.
For sleds, if the molded body is placed on a flat test bench and the molded body is in contact with the entire surface of the test bench, the sled ○, and the molded body can be tested by placing the molded body on a flat test bench. When the molded body is not in contact with the entire surface and the molded body is in contact with the entire surface of the test table with the finger when the molded body is pressed against the entire surface of the test table, warping is required. When the molded body was pressed against the table, if there was a portion where the molded body was not in contact with the test table, it was evaluated as a sled x and summarized in Tables 1-9.

<Comparison of substrate forms (Table 1)>
(Example 1)
Epoxy resin ("Epicoat (registered trademark)" 828: 30 parts by weight, "Epicoat (registered trademark)" 1001: 35 parts by weight, "Epicoat (registered trademark)" 154: 35 parts by weight, manufactured by Japan Epoxy Resin Co., Ltd. Then, 5 parts by weight of a thermoplastic resin polyvinyl formal (“Vinylec (registered trademark)” K manufactured by Chisso Corporation) was heated and kneaded with a kneader to uniformly dissolve the polyvinyl formal, and then a curing agent dicyandiamide (Japan Epoxy Resin Co., Ltd.) ) DICY7) 3.5 parts by weight and 4 parts by weight of curing accelerator 3- (3,4-dichlorophenyl) -1,1-dimethylurea (Hodogaya Chemical Co., Ltd. DCMU99) were kneaded in a kneader. Thus, an uncured epoxy resin composition was prepared. This epoxy resin composition was applied onto a release paper having a thickness of 100 μm that had been subjected to silicone coating using a reverse roll coater to prepare a resin film. Next, a resin film is laminated on both sides of carbon fibers arranged in one direction (tensile strength 4,900 MPa, tensile elastic modulus 235 GPa), and the resin is impregnated by heating and pressing, so that the carbon fiber weight per unit area is increased. A prepreg base material having a thickness of 125 g / m ² , a fiber volume content Vf of 55%, and a thickness of 0.125 mm was produced.

  To this prepreg base material, after continuously inserting a linear cut in the direction of 10 ° from the fiber as shown in FIG. 4a) using an automatic cutter, the orientation direction of the carbon fiber (0 ° direction), Each was cut into a size of 300 × 300 mm in a direction (45 ° direction) shifted 45 degrees to the right from the orientation direction of the carbon fibers, and prepreg base materials having regular cuts at equal intervals were obtained. Of these, the notch is not cut every 5 mm around 300 × 300 mm, and a notch that is not separated by continuous cutting is inserted in a direction of 10 ° from the fiber, and the other end from the vicinity of the end of the prepreg base material The incision was made in the range of 290 × 290 mm. The fiber length L divided by the cutting is 30 mm. The viscosity of the epoxy resin in an atmosphere at 25 ° C. was 2 × 10 4 Pa · s, and the substrate had tackiness.

The above-cut cut prepreg base material is laminated in a 16-layer pseudo-isotropic ([−45 / 0 / + 45/90] _2S ), and then is cut off by 25 mm perimeter, and a 250 × 250 mm laminated base material having cuts on the entire surface. Got.

  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 base material, 150 degreeCx30 under the pressurization of 6 MPa with a heating type press molding machine. Curing was performed under the condition of minutes, and a plate-like fiber reinforced plastic of 300 × 300 mm was obtained. When the ratio of the area of the base material to the mold area when the mold is viewed from above is defined as the charge rate, the charge rate corresponds to 70%.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There was no warpage as a whole, and there was almost no part where the reinforcing fiber was not present and the resin-rich or adjacent layer reinforcing fiber was peeking out even in the cut portion of the outermost layer, and good appearance quality and smoothness were maintained. . The tensile modulus was 46 GPa, which was almost the theoretical value, and the tensile strength was as high as 590 MPa, and the CV value was 5%. From these results, it was found that mechanical properties and quality that can be applied to structural materials and outer plate members were obtained. Further, when the obtained fiber-reinforced plastic was cut out and attention was paid to the layer having a cut-out surface of 0 °, there was no layer undulation or a portion where no fiber was present as shown in FIG. 6b), and there was almost no resin-rich portion. . Moreover, the fiber bundle end was also inclined in the thickness direction (about 5 ° or less from the fiber direction), and it was considered that the stress transmission efficiency was high.

(Example 2)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except for how to cut. After the prepreg base material obtained in the same manner as in Example 1 was intermittently inserted into the entire surface by linear cuts in the direction of ± 10 ° from the fiber as shown in FIG. Each of the fiber orientation direction (0 ° direction) and the direction shifted 45 degrees to the right from the carbon fiber orientation direction (45 ° direction) are each cut into a size of 300 × 300 mm and have regular cuts at equal intervals. A cut prepreg substrate was obtained. The projected length Ws projected in the vertical direction of the cut fiber is 10 mm (the actual cut length is 57.6 mm), and the fiber length L or less (about 15 mm in this embodiment) by the adjacent cut as shown in FIG. There was a site that was divided.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There was no warpage as a whole, and there was almost no part where the reinforcing fiber was not present and the resin-rich or adjacent layer reinforcing fiber was peeking out even in the cut portion of the outermost layer, and good appearance quality and smoothness were maintained. . The tensile modulus was 46 GPa, which was almost the theoretical value, and the tensile strength was as high as 550 MPa, and the CV value was 4%. Further, when the obtained fiber-reinforced plastic was cut out and attention was paid to the layer having a cut-out surface of 0 °, there was no layer undulation or a portion where no fiber was present as shown in FIG. 6b), and there was almost no resin-rich portion. . Moreover, the fiber bundle end was also inclined in the thickness direction (about 5 ° or less from the fiber direction), and it was considered that the stress transmission efficiency was high.

(Example 3)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except for how to cut. After the prepreg base material obtained in the same manner as in Example 1 is inserted into the entire surface by linear cutting in the direction of 10 ° from the fiber as shown in FIG. Cut into a size of 300 × 300 mm in a direction of 45 ° to the right (0 ° direction) and 45 ° to the right of the carbon fiber orientation direction (45 ° direction), and have regular cuts at regular intervals. An embedded prepreg substrate was obtained. The projected length Ws projected in the vertical direction of the cut fiber is 10 mm (actual cut length is 57.6 mm), and is cut to the fiber length L or less (this time around 15 mm) by the adjacent cut as shown in FIG. There was a site to be.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There was no warpage as a whole, and there was almost no part where the reinforcing fiber was not present and the resin-rich or adjacent layer reinforcing fiber was peeking out even in the cut portion of the outermost layer, and good appearance quality and smoothness were maintained. . The tensile modulus was 46 GPa, which was almost the theoretical value, the tensile strength was as high as 580 MPa, and the CV value was 5%, which was very small. Further, when the obtained fiber-reinforced plastic was cut out and attention was paid to the layer having a cut-out surface of 0 °, there was no layer undulation or a portion where no fiber was present as shown in FIG. 6b), and there was almost no resin-rich portion. . Moreover, the fiber bundle end was also inclined in the thickness direction (about 5 ° or less from the fiber direction), and it was considered that the stress transmission efficiency was high.

<Comparison of reinforcing fiber and matrix resin (Table 2)>
Example 4
Cut off in the same manner as in Example 1 except that the curing accelerator was changed to 5 parts by weight of 2,4-toluenebis (dimethylurea) ("OMICURE (registered trademark)" 24 manufactured by PTI Japan). An embedded prepreg base material and a laminated base material using the same were prepared. A fiber-reinforced plastic was obtained in the same manner as in Example 1 except that only the pressing time (curing time) of the heating press molding machine was changed to 3 minutes. Despite the pressurization time being 1/10 that of Example 1, the glass transition temperature was almost the same, and it was found that the epoxy resin composition was excellent in rapid curability.

  None of the obtained fiber reinforced plastics had any fiber undulations, and the fibers were flowing evenly to the ends. In addition, there was no warp, and there was almost no portion where the reinforcing fiber was not present and the reinforcing fiber in the adjacent layer was not present in the cut portion of the outermost layer, and good appearance quality and smoothness were maintained. The tensile elastic modulus was 47 GPa and the tensile strength was high as 580 MPa, and the CV value of the tensile strength was 4% and the variation was small. These values were comparable to those in Example 1.

(Example 5)
In the same manner as in Example 4 except that the curing accelerator was changed to 7 parts by weight of 4,4-methylenebis (phenyldimethylurea) (“OMICURE (registered trademark)” 52) manufactured by PTI Japan Ltd. A fiber reinforced plastic was obtained. Despite the pressurization time being 1/10 of that of Example 1, it was found that the uncured epoxy resin composition was excellent in rapid curability, showing almost the same glass transition temperature.

  None of the obtained fiber reinforced plastics had any fiber undulations, and the fibers were flowing evenly to the ends. In addition, there was no warp, and there was almost no portion where the reinforcing fiber was not present and the reinforcing fiber in the adjacent layer was not present in the cut portion of the outermost layer, and good appearance quality and smoothness were maintained. The tensile modulus was 47 GPa and the tensile strength was as high as 580 MPa, and the CV value of the tensile strength was as small as 5%. These values were comparable to those in Example 1.

(Example 6)
Pellets of copolymerized polyamide resin (“Amilan” (registered trademark) CM4000 manufactured by Toray Industries, Inc., polyamide 6/66/610 copolymer, melting point 155 ° C.) were formed into a film having a thickness of 34 μm with a press heated at 200 ° C. processed. A cut prepreg base material was prepared in the same manner as in Example 1 except that the release paper was not used. 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. After cutting in the same manner as in Example 1, since there is no tackiness, 16 layers are simply stacked in a pseudo isotropic manner ([−45 / 0 / + 45/90] _2S ), and a plate mold having a 300 × 300 mm cavity is left as it is. It was arranged at the approximate center. It was made to flow at 200 ° C for 1 minute under a pressure of 6 MPa with a heated die press, cooled without opening the mold, demolded, and reinforced with a flat fiber of 300 x 300 mm. Got plastic.

  Although the obtained fiber reinforced plastic had some fiber undulations, the fibers flowed to the end. Slight warpage occurred due to slight density of the fiber distribution, but in the outermost notch, there was almost no part where the reinforcing fiber was not present and the reinforcing fiber in the adjacent layer was not visible, and it was generally good. Appearance quality and smoothness were maintained.

(Example 7)
55% by weight of random copolymer PP resin (Prime Polymer Co., Ltd. J229E, melting point 155 ° C.) and acid-modified PP resin (Sanyo Chemical Co., Ltd. Yumex 1010, acid value about 52, melting point 142 ° C., weight average molecular weight 30 , 000) 45% by weight of a pellet obtained by melting and kneading at 200 ° C. using a twin-screw extruder (TEX-30α2) manufactured by Nippon Steel Works Co., Ltd. into a 34 μm-thick film form using a press heated at 200 ° C. processed. Thereafter, a fiber reinforced plastic was obtained in the same manner as in Example 6.

  Although the obtained fiber reinforced plastic had some fiber undulations, the fibers flowed to the end. Slight warpage occurred due to slight density of the fiber distribution, but in the outermost notch, there was almost no part where the reinforcing fiber was not present and the reinforcing fiber in the adjacent layer was not visible, and it was generally good. Appearance quality and smoothness were maintained.

(Example 8)
A resin film was prepared in the same manner as in Example 1. Next, resin films are superimposed on both surfaces of glass fibers arranged in one direction (tensile strength 1,500 MPa, tensile elastic modulus 74 GPa), and impregnated with resin by heating and pressurization, and the glass fiber weight is 175 g / m. ^2. A cut prepreg base material having a fiber volume content Vf of 55% and a thickness of 0.125 mm was prepared. Thereafter, a fiber reinforced plastic was obtained in the same manner as in Example 1.

  None of the obtained fiber reinforced plastics had any fiber undulations, and the fibers were flowing evenly to the ends. In addition, there was no warp, and there was almost no portion where the reinforcing fiber was not present and the reinforcing fiber in the adjacent layer was not present in the cut portion of the outermost layer, and good appearance quality and smoothness were maintained. Although the tensile elastic modulus is 29 GPa and the tensile strength is 430 MPa, the performance difference of the reinforcing fiber is lower than that of Example 1, the tensile elastic modulus is expressed close to the theoretical value, and the CV value of the tensile strength varies as 3%. The result was small.

<Comparison of cutting angle (Table 3)>
(Examples 9 to 12)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the cutting angle was changed. In Example 9, the angle from the fiber was 2 °, Example 10 was 5 °, Example 11 was 15 °, and Example 12 was provided with a continuous cut in the direction of 25 °.

  None of the obtained fiber reinforced plastics had any fiber undulations, and the fibers were flowing evenly to the ends. In addition, there was no warp, and there was almost no portion where the reinforcing fiber was not present and the reinforcing fiber in the adjacent layer was not present in the cut portion of the outermost layer, and good appearance quality and smoothness were maintained. The tensile modulus was 46 to 47 GPa, the tensile strength was as high as 460 to 660 MPa, and the CV value of the tensile strength was as small as 3 to 6%. In particular, in Examples 9 and 10 having a small cutting angle, a tensile strength of 600 MPa or more was expressed. On the other hand, since the cutting angle was small in Example 9, the interval between the cuttings was as small as about 1 mm, and the handling at the time of lamination was slightly difficult. there were.

<Comparison of charge rates (Table 4)>
(Examples 13 to 15)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the size of the cut prepreg base material to be cut out was different. The size of the cut prepreg base material to be cut out was 212 × 212 mm in Example 13, 285 × 285 mm in Example 14, and 300 × 300 mm in Example 15. Example 13 corresponds to 50% charge rate, Example 14 corresponds to 90%, and Example 15 corresponds to 100%.

  All of the obtained fiber reinforced plastics did not swell, and the fibers sufficiently flowed to the end thereof (however, Example 15 was not flowing because of 100% charge). In Example 13, since it was made to flow for a long distance, a slight warp was generated due to a slight density of the fiber distribution, but the reinforcing fiber was not present in the cut portion of the outermost layer, and the reinforcing fiber in the resin-rich or adjacent layer was not present. There were almost no peeping parts, and generally good appearance quality and smoothness were maintained. In Examples 14 and 15, there is no warp, and there is no portion in which the reinforcing fiber is not present and the reinforcing fiber in the adjacent layer is not in the cut portion of the outermost layer, and the appearance quality and smoothness are good. Was kept. The tensile modulus was 46 to 47 GPa, the tensile strength was as high as 510 to 690 MPa, and the CV value of the tensile strength was also as small as 3 to 7%. In particular, in Example 13 where the charge rate is small, the layer thickness of the fiber reinforced plastic obtained because the cut prepreg base material is thinly stretched is an effect that the delamination from the fiber bundle end portion is less likely to occur, The tensile strength expressed a very high value of 690 MPa.

<Comparison of fiber length (Table 5)>
(Examples 16 to 18)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the fiber length L was changed by changing the cut interval in the cut pattern of Example 1. L was 10 mm in Example 16, 60 mm in Example 17, and 100 mm in Example 13, respectively.

  The obtained fiber reinforced plastic had no fiber swell except for Example 18, and the fiber sufficiently flowed to its end. In Example 13, there was a portion where the fiber did not sufficiently flow to the end at the surface portion where the undulation of the fiber and friction with the mold were received. In addition, none of the fiber reinforced plastics has warpage, and there is almost no part where the reinforcing fibers are not present and the reinforcing fibers in the adjacent layer are not present in the cut portion of the outermost layer, and the appearance quality is smooth and smooth. I kept the sex. The tensile modulus was 46 to 47 GPa, the tensile strength was as high as 510 to 650 MPa, and the CV value of the tensile strength was also as small as 3 to 6%.

<Comparison of cutting length (Table 6)>
(Examples 19 to 21)
In the cutting pattern of Example 3, instead of an automatic cutting machine, a cylindrical metal is cut out, a plurality of blades are provided on the circumference to form a rotating roller, and pressed against a prepreg base material in a direction of 10 ° from the fiber. A fiber reinforced plastic was obtained in the same manner as in Example 3 except that the length of the cut was changed by making a straight cut. The projected length Ws projected in the vertical direction of each cut fiber was 17 μm in Example 19, 30 μm in Example 20, and 170 μm in Example 21. The actual cut lengths were 0.1 mm in Example 19, 0.17 mm in Example 20, and 1 mm in Example 21, respectively.

  The obtained fiber reinforced plastic had no fiber swell except in Example 19. In Example 19, local disturbance of flow occurred due to the presence of many cut edges, and some fiber undulation was observed. In addition, in all the fiber reinforced plastics, the fibers are sufficiently flowing to the end thereof, there is no warp, and there is no reinforcing fiber in the cut portion of the outermost layer. There were almost no parts, and good appearance quality and smoothness were maintained. The tensile modulus was 47 GPa and the tensile strength was a high value of 690 to 7130 MPa. Although the CV value of the tensile strength was a little high at 9% in Example 19, the others were 4 to 5% and the variation was small.

(Examples 22 to 25)
A fiber reinforced plastic was obtained in the same manner as in Example 3 except that the length of the cut in the cut pattern of Example 3 was different. The projected length Ws projected in the vertical direction of each cut fiber was 1 mm in Example 22, 1.5 mm in Example 23, 100 mm in Example 24, and 120 mm in Example 225. The actual cut lengths were 5.8 mm in Example 22, 8.6 mm in Example 23, and large cuts that did not fit in the 300 × 300 mm cut prepreg substrate prepared in Examples 24 and 25, respectively. It was almost a continuous cut with one end of the cut inside.

  All of the obtained fiber reinforced plastics have no fiber undulation, the fibers are sufficiently flowing to the end thereof, no warp, and no reinforcing fibers are present in the cut portion of the outermost layer. There were almost no portions where the reinforcing fibers of the adjacent layer were peeked, and good appearance quality and smoothness were maintained. The tensile modulus was 45 to 47 GPa and the tensile strength was a high value of 580 to 640 MPa. The CV value of the tensile strength was 3 to 6%, which was a small variation. On the other hand, since Examples 24 and 25 were almost continuous cuts, the ends of the cut prepreg base material were scattered during lamination, and the handleability was poor.

<Comparison of layer thickness (Table 7)>
(Examples 26 and 27)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the thickness of the cut prepreg base material was changed by changing the weight of the carbon fiber per unit area of the prepreg base material of Example 1. In Example 26, the carbon fiber weight per unit area was 50 g / m ² , the thickness of the cut prepreg base material was 0.05 mm, and Example 27 was 300 g / m ² and 0.3 mm.

  All of the obtained fiber reinforced plastics have no fiber undulations, the fibers are sufficiently flowing to the end, no warp, and there is no reinforcing fiber even in the outermost notch, and the resin rich or adjacent There were almost no portions where the reinforcing fibers of the layer were peeking, and good appearance quality and smoothness were maintained. Although the tensile modulus was 46 to 47 GPa and the tensile strength was as high as 750 MPa in Example 26, while Example 27 was slightly low as 370 MPa, the CV value of the tensile strength was 4 to 5%, showing little variation. In particular, it was found that the tensile strength was improved by reducing the thickness of the cut prepreg base material.

<Comparison of fiber content (Table 8)>
(Examples 28 and 29)
A fiber-reinforced plastic was obtained in the same manner as in Example 1 except that the volume content Vf of the carbon fiber was changed by changing the carbon fiber weight per unit area of the prepreg base material of Example 1. Each Example 28 is carbon fiber weight per unit area 146 g ^/ m 2, Vf is 65%, Example 29 was 101g ^/ m 2, Vf is 45%.

  In Example 28, the obtained fiber reinforced plastic had a portion where the fiber did not sufficiently flow to the end at the surface portion where the undulation of the fiber and friction between the mold and the mold were received. On the other hand, in the fiber reinforced plastic obtained in Example 29, the fibers did not swell, and the fibers sufficiently flowed to the ends. In addition, both fiber reinforced plastics have no warp, and there is almost no portion where the reinforcing fibers are not present and the reinforcing fibers in the adjacent layer are not present in the cut portion of the outermost layer, and the appearance quality is smooth and smooth. I kept the sex. The tensile elastic modulus was 39 to 52 GPa, the tensile strength was as high as 490 to 630 MPa, and the CV value of the tensile strength was also as small as 4 to 8%. As Vf increased, the tensile modulus and strength were improved. However, when Vf was too large, there was a problem that the fluidity decreased.

<Comparison of laminated structures (Table 9)>
(Examples 30 and 31)
Example 30 obtained the fiber reinforced plastic like Example 1 except having changed the laminated structure of Example 1. FIG. A [0/90] _4s laminated base material in which the cut prepreg base material into which the cuts of Example 1 were cut was laminated on a 16-layer cross ply was used. Example 31 obtained a fiber-reinforced plastic in the same manner as in Example 1 except that the prepreg base material of Example 1 and the cut prepreg base material after being cut were combined and laminated. [0 / C90] _4s (C is a continuous fiber only). 8 layers of prepreg base material composed only of continuous fibers without cut and 8 layers of cut prepreg base material with cuts were alternately laminated on a cross ply. The laminated base material of the prepreg base material comprised was used.

  All of the obtained fiber reinforced plastics had no fibers swelled, and the fibers were sufficiently flowing to the ends thereof. Although some warping occurred in Example 30, there was almost no portion in which the reinforcing fiber was not present and the resin-rich or the reinforcing fiber in the adjacent layer was peeking out even in the cut portion of the outermost layer. I kept the sex. The tensile elastic modulus was 63 to 64 GPa, the tensile strength was a high value of 680 to 690 MPa, and the CV value of the tensile strength was 4 to 5%, which was a small variation. However, since the direction of the tensile test is the 0 ° direction, very high mechanical properties are shown. However, since the fibers are not oriented in the ± 45 ° direction, there is a problem that it is not general-purpose.

(Examples 32-34)
Example 32 obtained the fiber reinforced plastic like Example 1 except having changed the laminated structure of Example 1. FIG. A [ _60/0 / −60] _2s laminated base material obtained by laminating the cut prepreg base material into which the cuts of Example 1 were made in a 12-layer pseudo-isotropic manner was used. In Example 33, in addition to the notched prepreg base material into which the incision was made in Example 1, a fiber layer was reinforced in the same manner as in Example 1 except that a resin layer having the epoxy resin film of Example 1 transferred between the layers was inserted. Got plastic. When the cut prepreg base material into which the cut of Example 1 was cut is laminated in a 16-layer pseudo-isotropic manner, a resin layer is provided and [45 / R / 0 / R / −45 / R / 90 / R] _2s (R Is a resin layer). Eventually Vf was 49%. In Example 34, in addition to the cut prepreg base material into which the incision was made in Example 1, a plain weave prepreg base material having a Vf 55% layer thickness of 250 μm and impregnated with the same epoxy resin as in Example 1 was arranged on the outermost layer. A fiber reinforced plastic was obtained in the same manner as in Example 1. The cut prepreg base material into which the incision of Example 1 was cut was laminated in a 16-layer pseudo-isotropic manner, and the plain weave prepreg base material in which the fiber directions were oriented at 0 ° and 90 ° was further laminated on the outermost layer [WF0 / 45/0 / −45 / 90] _2s (WF refers to plain weave prepreg substrate) was used.

  In the fiber reinforced plastics obtained in Examples 32 and 33, the fibers did not swell, and the fibers sufficiently flowed to the ends. Especially Example 33 was excellent in fluidity | liquidity and the fiber spread very uniformly. None of them were warped, and even in the cut portion of the outermost layer, there was almost no portion where the reinforcing fibers were not present and the reinforcing fibers of the resin layer or the adjacent layer were peeking, and good appearance quality and smoothness were maintained. The tensile elastic moduli were 46 GPa and 42 GPa, the tensile strengths were 5980 MPa and 510 MPa, high values corresponding to Vf, and the CV values of the tensile strength were 6% and 4%, which were small variations. In the fiber reinforced plastic obtained in Example 34, although the plain weave portion of the outermost layer did not flow at all, the portion of the portion sandwiched between the plain weave portions was sufficiently flowed to the end. Although fiber swells at the ends and resin-rich and fiber reinforced fibers in the adjacent layers are observed at the ends of the fiber bundle, there is no warpage overall and good appearance quality and smoothness are maintained. It was. High mechanical properties were exhibited by hybridization with a tensile modulus of 54 GPa and a tensile strength of 670 MPa.

(Example 35)
A resin film was prepared in the same manner as in Example 1, and the resin film was completely impregnated in the carbon fiber when the resin films were stacked on both sides of the carbon fiber arranged in one direction as in Example 1, and heated and pressurized. A semi-impregnated prepreg base material having a carbon fiber weight of 125 g / m ² per unit area and a fiber volume content Vf of 55% was prepared. A cut as shown in FIG. 1 was inserted into this semi-impregnated prepreg substrate in the same manner as in Example 1. Although the obtained cut prepreg base material has a region that is not impregnated with resin in the central portion in the thickness direction, it has sufficient handleability as in Example 1 without fluffing or being separated by the cut. I kept it. Furthermore, it laminated and shape | molded similarly to Example 1, and obtained the fiber reinforced plastic.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. Moreover, there was no warp and good appearance quality and smoothness were maintained. The tensile elastic modulus was 46 GPa, the tensile strength was as high as 550 MPa, and the CV value was 7%, which was a small variation.

<Comparison of cut prepreg base material cut from both sides (Table 10)>
(Examples 36 to 38)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that in the step of making a cut in the prepreg base material of Example 1, a notch that did not penetrate through the thickness direction of the layer from each of the upper surface and the lower surface of the prepreg base material was made. . The rotary roller provided with a spiral blade exposed for a predetermined length shown in FIG. 78 is pressed in the order of the upper surface and the lower surface of the prepreg base material so as not to penetrate through the thickness direction of the prepreg base material layer. I put it in. When the cut into the upper surface of the cut prepreg base material is U and the lower surface is D, the depth of cut Hs and u in Example 36 is 35 μm (0.28H, where H is the thickness of the cut prepreg base material), D cut depth Hs, d is 100 μm (0.8H), U cut depth Hs, u in Example 37 is 55 μm (0.44H), and D cut depth Hs, d is 75 μm ( 0.6H), in Example 38, both U and D had a depth of cut Hs (= Hs, d, Hs, u) of 67 μm (0.54H). The cut angle on the upper surface was 10 °, and the cut angle on the lower surface was −10 °. The fibers of the cut prepreg base material were divided by the upper and lower cuts, and all the fiber lengths were 30 mm or less.

  None of the obtained fiber reinforced plastics had any fiber undulations, and the fibers sufficiently flowed to the ends. In Example 36, although some warping occurred, there was almost no portion where the reinforcing fiber was not present and the reinforcing fiber in the adjacent layer was not present in the cut portion of the outermost layer, and a good appearance Quality and smoothness were maintained. The tensile modulus of elasticity was 45 to 46 GPa, which was expressed as the theoretical value, and the tensile strength was 650 to 750 MPa, which was higher than that of Example 1. In particular, a higher tensile strength was obtained as the cut depth between the upper surface and the lower surface was closer. This is considered to be due to the effect that the thickness of the end portion of the fiber bundle can be minimized because the cut amounts of the upper surface and the lower surface are equal.

(Example 39)
Using the cut prepreg base material of Example 1, lamination was performed so that the cut angle was 10 ° and −10 ° with respect to the fiber direction on the upper surface and the lower surface to obtain a two-layer laminated base material. The two-layer laminated substrate thus obtained was laminated and molded in the same manner as in Example 1 as a cut prepreg substrate for one layer to obtain a fiber reinforced plastic. When the two-layer laminated substrate is regarded as a single-layer cut prepreg substrate, the Hs of U and D are both 125 μm (0.5H) deep.

  None of the obtained fiber reinforced plastics have undulations in the fibers, and there is almost no part where the reinforcing fibers are present and the reinforcing fibers in the adjacent layer are not present in the cut portion of the outermost layer, and a good appearance Quality and smoothness were maintained. The tensile elastic modulus is expressed as 47 GPa almost as theoretical value, and the tensile strength is 690 MPa, which is higher than that of Example 1 and Examples 36 to 38, although the thickness per layer is twice. As a result, the CV value of the tensile strength was 4 and the variation was small. It seems that high strength was developed because the structure is such that the fibers are arranged in the direction to stop the opening of the notch next to the notch.

<Comparison of cut prepreg base material cut obliquely in thickness direction (Table 11)>
(Examples 40 to 44)
After cutting into the prepreg base material of Example 1, a fiber reinforced plastic was obtained in the same manner as in Example 1 except that a shearing force was applied in the thickness direction of the cut prepreg base material to make the cutting diagonal. After making a vertical cut in the cut prepreg base material that penetrates the thickness direction of the layer as in Example 1, the rotational speed of the upper surface and the lower surface is heated and softened at 60 ° C. A nip roller having a different thickness was pressed against each other, and a shearing force was applied to make the reinforcing fiber's partial cross section slant in the thickness direction. As shown in FIG. 12, when the distance 24 in the fiber direction between the cut line of the reinforcing fiber on the upper surface of the cut prepreg substrate and the cut line on the lower surface is the shear distance S, the cut prepreg substrate cut into 250 × 250 mm Then, the shear distance S was measured at five notches, and the averaged value was substituted into (Equation 1) to calculate the angle 26 formed by the notch, that is, the inclination angle θ of the notch. Example 40 has a shear distance S of 12.5 mm and a cutting inclination angle θ of 0.6 °, Example 41 has S of 6.25 mm and θ of 1.1 °, Example 42 has S of 1 mm, and θ is 7.1 °, Example 43 had S of 0.5 mm and θ of 1.4 mm, and Example 44 had S of 0.25 mm and θ of 27 °.

  None of the obtained fiber reinforced plastics had any fiber undulations, and although Example 40 produced some warping, none of the outermost cuts were resin-rich or adjacent to the adjacent layer. There were almost no portions where the reinforcing fibers were peeked out, and good appearance quality and smoothness were maintained. The tensile elastic modulus is expressed as 46 to 47 GPa almost as theoretical values, and the tensile strength is 580 MPa in Example 40, 620 MPa in Example 41, 620 MPa in Example 42, 610 MPa in Example 43, and 590 MPa in Example 44. Even compared with Example 1, it was comparable or more. However, in Example 40 in which the inclination angle of the fiber bundle end portion was 1 ° or less, the shear distance S was very long, the variation in S for each cut portion was large, and the process stability was lacking.

<Comparison of application area of additional resin (Table 12)>
(Example 45)
As an additional resin, pellets of a copolymerized polyamide resin (“Amilan” (registered trademark) CM4000, polyamide 6/66/610 copolymer, melting point 155 ° C., manufactured by Toray Industries, Inc.) were melt blown and the resin weight per unit area was 30 g. A nonwoven fabric of / m ² was created. The viscosity of the polyamide resin in an atmosphere at 25 ° C. was a solid and could not be measured, and the nonwoven fabric substrate did not have tackiness. After the obtained non-woven fabric base material is cut into a strip shape having a width of 0.2 mm, the non-woven fabric base material is cut in a strip shape so as to cover all continuous cuts on both sides of the same cut prepreg base material as in Example 1. Was placed so as to be the center of the width (± 0.1 mm in the fiber direction). The nonwoven fabric substrate adhered to the cut prepreg substrate simply by pressing the epoxy resin tack. The fiber volume content Vf of the composite cut prepreg base material thus obtained was equivalent to 53%. This composite cut prepreg base material was laminated and molded to obtain a fiber reinforced plastic.
In addition, when this composite cut prepreg base material was cured only in one layer without applying pressure as it was in an oven at 130 ° C. for 2 hours, and the cross section was cut out, the layer thickness of the portion having no additional resin layer was 125 μm on average. On the other hand, the layer thickness of the portion where the additional resin layer exists on both surfaces was 175 μm on average, although the additional resin layer was not a uniform thickness because it was a nonwoven fabric. When the portion where the additional resin layer exists on both sides is cut out in a plane perpendicular to the fiber direction and observed with an optical microscope, the additional resin layer exists around the reinforcing fiber at a depth of about 10 μm from the layer surface of the cut prepreg substrate. It was confirmed that the additional resin layer did not penetrate into the layer of the cut prepreg base material without exceeding 10% as compared with the entire area occupied by the additional resin layer in the sectional view, The thickness of the additional resin layer was found to be about 25 μm on average.

  The obtained fiber reinforced plastic has no fiber undulation, and there is almost no part where the reinforcing fiber is not present and the reinforcing fiber in the adjacent layer is not present in the cut portion of the outermost layer, and the appearance quality is good. The smoothness was maintained. The tensile modulus was 45 GPa and the tensile strength was 580 MPa, which was the same level as in Example 1. There is a possibility that not all of the cuts were covered because the width of the non-woven fabric of the additional resin was very narrow.

(Examples 46 and 47)
A fiber reinforced plastic was obtained in the same manner as in Example 45 except that the area of the nonwoven fabric base material, which is an additional resin, was different. When cutting the tape-shaped nonwoven fabric base material, Example 46 is 3 mm wide, Example 47 is 20 mm wide, and the cut is tape-shaped nonwoven fabric base so that the cut is covered with the nonwoven tape. Arranged so that the center of the width of the material. Specifically, the distance from the cut to the width end of the nonwoven fabric substrate was arranged such that Example 46 was ± 1.5 mm in the fiber direction and Example 47 was ± 10 mm in the fiber direction. As in Example 45, the additional resin layer was arranged in layers, and it was confirmed that the additional resin layer did not enter the layer of the cut prepreg base material, and the average thickness was about 25 μm.

  None of the obtained fiber reinforced plastics have any undulation of the fiber, and none of the outermost incised portions are resin-rich or there are almost no parts where the reinforcing fibers of the adjacent layer are peeking out and are good. Appearance quality and smoothness were maintained. While the tensile elastic modulus was slightly reduced to 37 to 44 GPa, the tensile strength was 590 to 680 MPa, and high physical properties equivalent to or higher than those of Example 1 were exhibited. In Example 47, the elastic modulus and the tensile strength tended to slightly decrease as the area covered by the additional resin increased.

(Example 48)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the nonwoven fabric base material, which was an additional resin obtained in the same manner as in Example 45, was applied to the entire surface of both sides of the cut prepreg base material in Example 1. . As in Example 45, the additional resin layer was arranged in layers, and it was confirmed that the additional resin layer did not enter the layer of the cut prepreg base material, and the average thickness was about 25 μm.

  None of the obtained fiber reinforced plastics have undulations in the fibers, and there is almost no part where the reinforcing fibers are present and the reinforcing fibers in the adjacent layer are not present in the cut portion of the outermost layer, and a good appearance Quality and smoothness were maintained. The tensile strength was 590 MPa, which was the same as in Example 1. However, the tensile modulus dropped significantly due to the decrease in 34 GPa and Vf, but the additional resin with a high tensile elongation was disposed on the entire surface of the interlayer. The effect which the durability with respect to an external load improves was acquired.

<Comparison of laminated structures (Table 9)>
(Reference Examples 1 and 2)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the laminated structure of Example 1 was changed. In Reference Example 1, a laminated substrate of [0] _{8 obtained} by laminating 8 cut prepreg substrates into which the cuts of Example 1 were made in the same direction was used. In Reference Example 2, a [0/45] _4s laminated base material obtained by laminating 16 layers of the cut prepreg base material into which the cuts of Example 1 were made was used.

  The fiber reinforced plastic obtained in Reference Example 1 flowed only in the 90 ° direction, and in the 0 ° direction, there was a portion where the fiber protruded like a whisker, but it was basically not flowing. The squeezed resin collected in the cavity of the 0 ° direction cavity, and the appearance quality was poor. Although the fiber reinforced plastic obtained in Reference Example 2 was flowing throughout the cavity, the flow of fibers was anisotropic as in the laminated structure, and the undulation of the fibers was large. Further, the obtained fiber reinforced plastic had a large warp. In addition, in any of the fiber reinforced plastics, there were many sites where the resin-rich portion and the reinforcing fibers in the adjacent layer were peeking out in the cut portion of the outermost layer.

  Hereinafter, a comparative example is shown.

<Comparison of substrate forms (Table 1)>
(Comparative Example 1)
The procedure was the same as Example 1 except that the prepreg base material was not cut.

  The obtained fiber reinforced plastic hardly flowed from the stage of the laminated base material and was approximately 250 × 250 mm in size, and the matrix resin was squeezed out and a resin burr was formed in the gap with the mold. Because the resin was squeezed out, the surface was squeezed and it seemed impossible to apply it to the product.

(Comparative Example 2)
A resin film coated with a thick epoxy resin composition similar to that in Example 1 was prepared. Next, a carbon fiber bundle (tensile strength 4,900 MPa, tensile elastic modulus 235 GPa, 12,000 fibers) cut to a length of 25 mm is uniformly applied on the resin film so that the weight per unit area becomes 125 g / m ^2. Dropped and sprayed. Further, after covering another cut carbon fiber, the cut carbon fiber was sandwiched, and then passed through a calender roll to prepare an SMC sheet having a fiber volume content Vf of 55%. This SMC sheet was cut out into 250 × 250 mm, and 16 layers were laminated to obtain a laminated base material, and then molded 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 portion. On the other hand, warping occurred slightly, but sinking occurred in the resin-rich part due to the coarse and dense fiber distribution, and the smoothness was poor. The tensile elastic modulus was 33 GPa, which was considerably lower than the theoretical value because the fiber was not straight, the tensile strength was 220 MPa, and the CV value was as large as 12%, which was unlikely to be applicable to structural materials.

(Comparative Example 3)
100 parts by weight of vinyl ester resin (manufactured by Dow Chemical Co., Ltd., Delaken 790) as a matrix resin, 1 part by weight of tert-butyl peroxybenzoate (manufactured by NOF Corporation, Perbutyl Z) as a curing agent, internally separated Using 2 parts by weight of zinc stearate (manufactured by Sakai Chemical Industry Co., Ltd., SZ-2000) as a mold, and 4 parts by weight of magnesium oxide (Kyowa Chemical Industry Co., Ltd., MgO # 40) as a thickener, They were thoroughly mixed and stirred to obtain a resin paste. The resin paste was applied onto a polypropylene release film using a doctor blade. From there, the carbon fiber bundles cut to a length of 25 mm as in Comparative Example 2 were uniformly dropped and dispersed so that the weight per unit area was 500 g / m ² . Further, it was sandwiched between the other polypropylene film coated with the resin paste with the resin paste side inward. The volume content of 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 250 × 250 mm, and four layers were laminated to obtain a laminated base material, and then molded 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 portion. While slight warpage occurred, the smoothness was superior to that of Comparative Example 2 due to the greater amount of resin-containing components, but some sinking occurred. The tensile modulus was 30 GPa, the tensile strength was as low as 160 MPa as a whole, and the CV value of the tensile strength was as large as 16%, so it was not likely to be applicable to structural materials.

(Comparative Example 4)
A resin paste was prepared in the same manner as in Comparative Example 3 and the resin paste was applied onto a polypropylene film, and then a glass fiber bundle (tensile strength 1,500 MPa, tensile elastic modulus 74 GPa, 800 pieces) cut to a length of 25 mm was used as a unit. It was dropped and sprayed uniformly so that the weight per area was 700 g / m ² . Thereafter, a fiber-reinforced plastic was obtained in the same manner as in Comparative Example 3.

  In the obtained fiber reinforced plastic, fibers sufficiently flowed to the end portion. While slight warpage occurred, the smoothness was superior to that of Comparative Example 2 due to the greater amount of resin-containing components, but some sinking occurred. The tensile modulus was 15 GPa, the tensile strength was as low as 180 MPa as a whole, and the CV value of the tensile strength was as large as 14%, so it was unlikely to be applicable to a structural material.

<Comparison of cutting angle (Table 3)>
(Comparative Examples 5 and 6)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the cutting angle was changed. In Comparative Example 5, the angle from the fiber was 1 °, and in Comparative Example 6, continuous cutting was provided in the direction of 45 °.

  In Comparative Example 5, since the cutting angle was small, the interval between the cuttings was as small as about 0.5 mm, and cutting and lamination were difficult. In the obtained fiber reinforced plastic, fibers were slightly swelled because fibers that were not cut to 100 mm or less remained, but the fibers were flowing to the end. There was no warp, and even in the cut portion of the outermost layer, there was almost no portion where the reinforcing fiber was not present and the reinforcing fiber of the resin layer or the adjacent layer was peeking, and good appearance quality and smoothness were maintained. The tensile elastic modulus was as high as 45 GPa and the tensile strength was as high as 650 MPa, but the CV value of the tensile strength was as high as 10% and the production stability was lacking. On the other hand, in Comparative Example 6, there was no fiber undulation, and the fibers flowed evenly to the end. In addition, there was no warp, but there were many areas where the reinforcing fibers were not present in the notch of the outermost layer and the reinforcing fibers in the adjacent layer were peeking out, and there were some sink marks in those parts. . Although the tensile elastic modulus was 45 GPa, the tensile strength was 330 MPa, which was significantly lower than those of Example 1 and Examples 9-12.

(Comparative Example 7)
A fiber-reinforced plastic was obtained in the same manner as in Example 3 except that the cutting angle was 90 °. The notch pattern is as shown in FIG. 3 a, the notch length is 10 mm, and the fiber length L is 30 mm. Adjacent cut rows are offset by 10 mm in the direction perpendicular to the fiber. That is, there are two patterns of the cut row. Furthermore, the cuts in adjacent rows are cut into each other.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. In addition, there was no warp, but there were many areas where the reinforcing fibers were not present in the notch of the outermost layer and the reinforcing fibers in the adjacent layer were peeking out, and there were some sink marks in those parts. . The tensile elastic modulus was 43 GPa and the tensile strength was 430 MPa, which was significantly lower than those in Example 1 and Examples 9-12.

<Comparison of fiber length (Table 5)>
(Comparative Examples 8 and 9)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the fiber length L was changed by changing the cut interval in the cut pattern of Example 1. L was 7.5 mm in Comparative Example 8 and 120 mm in Comparative Example 9, respectively.

  In Comparative Example 8, the obtained fiber reinforced plastic had no fiber undulation, and the fiber sufficiently flowed to its end. Although there was no warp and good appearance quality and smoothness were maintained, the tensile strength was 4400 MPa, a value lower than those of Example 1 and Examples 16-18. As for Comparative Example 9, in the obtained fiber reinforced plastic, the fibers did not flow completely over the cavity of the mold, and a resin rich portion was observed at the end. The fibers swelled and warped.

<Comparison of layer thickness (Table 7)>
(Comparative Examples 10 and 11)
A fiber reinforced plastic was obtained in the same manner as in Example 1 except that the thickness of the cut prepreg base material was changed by changing the weight of the carbon fiber per unit area of the prepreg base material of Example 1. In Comparative Example 10, the carbon fiber weight per unit area was 25 g / m ² , the cut prepreg base material thickness was 0.025 mm, and Comparative Example 11 was 400 g / m ² , 0.4 mm.

  All of the obtained fiber reinforced plastics had no fiber undulations, the fibers sufficiently flowed to the ends thereof, no warpage, and good appearance quality and smoothness were maintained. However, Comparative Example 10 has a problem that the manufacturing cost becomes very high because the thickness of the cut prepreg base material is extremely thin. Moreover, it turned out that the tensile strength of the comparative example 11 is considerably low compared with 320 MPa and Example 1 and Examples 26 and 27.

<Comparison of fiber content (Table 8)>
(Comparative Examples 12 and 13)
A fiber-reinforced plastic was obtained in the same manner as in Example 1 except that the volume content Vf of the carbon fiber was changed by changing the carbon fiber weight per unit area of the cut prepreg base material of Example 1. In Comparative Example 12, the carbon fiber weight per unit area was 158 g / m ² , Vf was 70%, Comparative Example 13 was 90 g / m ² , and Vf was 40%.

  In the fiber reinforced plastic obtained in Comparative Example 12, the fibers swelled, and the fibers did not flow to the end at the surface portion that received friction with the mold. The surface portion had resin chipping, the appearance quality was poor, and warping occurred. The fiber reinforced plastic obtained in Comparative Example 13 had no warp and maintained good appearance quality and smoothness. However, the tensile elastic modulus was 36 GPa and the tensile strength was 440 MPa, which were considerably low values as compared with Examples 1 and 28 and 29.

It is an enlarged plan view which shows an example of the cutting pattern of the cutting prepreg base material of this invention. It is an enlarged plan view which shows an example of the cutting pattern of the cutting prepreg base material of this invention. It is a top view which shows several examples of the cutting pattern of the cutting prepreg base material for a comparison. It is a top view which shows several examples of the cutting pattern of the cutting prepreg base material of this invention. It is a top view and a sectional view showing an example of a layered product for comparison and fiber reinforced plastic. It is a top view and a sectional view showing an example of a layered product of the present invention and fiber reinforced plastic. It is a top view and a sectional view showing an example of a layered product of the present invention and fiber reinforced plastic. It is the schematic which shows an example of the manufacturing method of the cutting prepreg base material of this invention. It is the schematic which shows an example of the manufacturing method of the cutting prepreg base material of this invention. It is a top view which shows an example of the 2 layer laminated base material of this invention. It is sectional drawing which shows an example of the cutting prepreg base material of this invention. It is sectional drawing which shows an example of the cutting prepreg base material of this invention. It is sectional drawing which shows an example of the cutting prepreg base material 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: continuous cut 4b (4b ₁ , 4b ₂ ): intermittent cut 4c: upper layer cut 4d: lower layer cut 4e: cut not penetrating in the thickness direction 4f: cut oblique in the thickness direction 5: cut And the angle Θ between the fiber direction
6: Fiber length L divided by a notch paired in the fiber direction
7: Cut prepreg base material 8: Width of the cuts cut into each other 9: Projected length Ws obtained by projecting the cut in the vertical direction of the reinforcing fiber
10: Laminated substrate 11: Fiber reinforced plastic 12: Short fiber layer 13: Region where no reinforcing fiber exists (cut opening)
14: Adjacent layer 15: Fiber bundle end 16: Resin rich portion 17: Layer waviness 18: Reinforcement fiber rotation
19: Rotating roller 20: Spiral blade 21: Two-layer base material 22: Cut prepreg base material thickness 23: Thickness direction width obtained by cutting each other on the lower surface of the upper surface 24: Shear distance S
25: Average fiber breaking line 26: Inclination angle θ of cut
27: Compound cut prepreg base material 28: Additional resin 29: Push cutting blade for inserting the cut 30: Rotary blade for end treatment 31: Moving head for arranging the prepreg base material (or fiber bundle) 32: Inserting the cut Rotating blade 33: Pre-preg base material longitudinal direction 34: Pre-preg base material width direction

Claims (21)

A prepreg base material composed of a reinforced fiber and a matrix resin aligned in one direction, and the entire surface of the prepreg base material has a cut within an absolute value of the angle Θ between the reinforcing fiber and 2 to 25 °. And substantially all the reinforcing fibers are divided by the incision, the fiber length L of the reinforcing fibers divided by the incision is in the range of 10 to 100 mm, and the thickness H of the prepreg base material is 30 to 300 μm. A cut prepreg base material having a fiber volume content Vf in the range of 45 to 65%. The cut prepreg base material according to claim 1, wherein the cut is linear. The cut prepreg base material according to claim 1 or 2, wherein all of the reinforcing fibers cut by the cut have a substantially constant fiber length L. The cut prepreg base material according to any one of claims 1 to 3, wherein the cuts are continuously made. The incision is an intermittent incision in which the projected length Ws projected in the vertical direction of the reinforcing fiber is within a range of 30 μm to 100 mm, and the incision and the incision adjacent to the incision in the fiber longitudinal direction have the same geometric shape The cut prepreg base material according to any one of claims 1 to 3. The cut prepreg base material according to claim 5, wherein the projected length Ws is within a range of 30 μm to 1.5 mm. The cut prepreg base material according to claim 5, wherein the projected length Ws is within a range of 1 to 100 mm. The cut prepreg substrate according to any one of claims 1 to 7, wherein the cut prepreg substrate is composed of carbon fibers and a thermosetting resin. The incision is provided obliquely in the thickness direction of the incision prepreg base material, and in an arbitrary incision, in the fiber direction of the reinforcing fiber dividing line on the upper surface of the incision prepreg base material and the dividing line on the lower surface When the distance is S, the angle θ derived from the following (Equation 1) using the cut prepreg base material thickness H is in the range of 1 to 25 °. The cut prepreg base material as described.

The incision is provided without penetrating the layers in the thickness direction from the upper surface and the lower surface of the incised prepreg base material, and the incision depth Hs is 0.4H to the incised prepreg base material thickness H. It is within the range of 0.6H, and the cut on the upper surface and the cut on the lower surface are cut into each other within the range of 0.01H to 0.1H. The cut prepreg base material according to any one of claims 1 to 8, wherein an angle Θb formed by the fiber direction of the cut B on the lower surface intersecting the cut A is -Θa-5 ° to -Θa + 5 °. It has a layered additional resin layer on at least one surface of the cut prepreg base material according to any one of claims 1 to 10, and the thickness of the additional resin layer is not less than the short fiber diameter of the reinforcing fiber, and A composite cut prepreg base material that is within a range of 0.5 times or less the thickness of the cut prepreg base material, the additional resin layer has a higher tensile elongation than the matrix resin, and the form is a film or a nonwoven fabric. . An additional resin having a higher tensile elongation than the matrix resin is formed on at least one surface of the cut prepreg substrate according to any one of claims 1 to 10 from the cut with respect to the cut prepreg substrate thickness H. Within the range of H to 100H in both directions of the fiber direction, it is arranged in layers on the surface of the cut prepreg base material without entering the layer formed by the reinforcing fibers, and the form of the additional resin is a film shape Or the composite cut prepreg base material which is a nonwoven fabric form. Two layers of the cut prepreg base material according to any one of claims 1 to 9, wherein a crossing angle of a lower cut D that intersects an arbitrary cut C of the upper layer of the two-layer base material is in a range of 4 to 90 °. Laminated substrate that is inside. A plurality of prepreg base materials, each comprising the cut prepreg base material according to any one of claims 1 to 12 and having a reinforcing fiber aligned in one direction, are laminated. A laminated base material in which the prepreg base material in which the reinforcing fibers are aligned in one direction is integrated with the fiber direction of the prepreg base material oriented in at least two directions. The laminated base material which the said laminated base material consists only of the cut prepreg base material in any one of Claims 1-12, and the said cut prepreg base material is laminated | stacked pseudo-isotropically. A fiber-reinforced plastic obtained by molding the laminated substrate according to claim 14 or 15. The layer in which the reinforcing fibers are substantially aligned in one direction is a fiber reinforced plastic obtained by laminating at least two layers in different directions of the reinforcing fibers, and the fiber volume content Vf is 45 to 65%. A plurality of slit openings formed on the entire surface of the layer without the presence of reinforcing fibers and formed only of the matrix resin or the reinforcing fibers of the adjacent layer, The fiber length L of the reinforcing fiber is divided within the range of 10 to 100 mm by the cut opening, the surface area of the cut opening at the layer surface is within the range of 0.1 to 10% of the surface area of the layer, and the average thickness A fiber reinforced plastic in which at least one short fiber layer having a Hc in the range of 15 to 300 μm is laminated. The fiber reinforced plastic according to claim 16 or 17, wherein an area of the outermost layer of the fiber reinforced plastic is substantially zero. It is a manufacturing method of the cut prepreg base material in any one of Claims 1-10, Comprising: Reinforcing fiber is aligned in one direction, a matrix resin is impregnated, a preliminary | backup prepreg base material is prepared, A preliminary | backup prepreg base material The manufacturing method of the cutting prepreg base material which presses the rotary blade roller which has arrange | positioned the blade on the roller helically, and makes a cut. It is a manufacturing method of the notch prepreg base material of Claim 9, Comprising: Reinforcing fiber is aligned in one direction, a matrix resin is impregnated, a preliminary | backup prepreg base material is prepared, a preliminary | backup prepreg base material is helically formed. A rotary blade roller with a blade placed on the roller is pressed from either the upper surface or the lower surface to make a cut that does not penetrate the thickness direction of the layer of the cut prepreg base material, and then the rotary blade roller is moved to the lower surface or the upper surface. A method for producing a cut prepreg base material, in which a notch that does not penetrate in the thickness direction of the layer is inserted in the thickness direction of the cut prepreg base material by pressing from any one of the above. A method for producing a fiber-reinforced plastic having a multi-layer laminated structure composed of reinforcing fibers and a matrix resin, wherein the laminated base material of claim 14 or 15 is pressurized within a range of 50 to 95% charge rate. A method for producing a fiber-reinforced plastic, which is molded and the area of the cut opening is substantially zero in the outermost layer.

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