JP2009286817A - Laminated substrate, fiber-reinforced plastic, and methods for producing them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate substrate which is excellent in a handling property and in a shape-following property to complicated shapes, can be molded in a short time, and expresses excellent dynamic physical properties including impact resistance applicable to structural materials, their low irregularity, and excellent dimensional stability, when processed into fiber-reinforced plastics. <P>SOLUTION: Provided is an intermediate substrate which is a flat plate-like laminated substrate 10 produced by arranging prepreg layers 7, comprising a plurality of unidirectionally oriented reinforcing fibers and a thermoplastic resin, in two or more directions and then integrating the prepreg layers, characterized in that the whole surfaces of the prepreg layers have linear notches 4 at an angle Θ in an absolute value range of 2 to 25 degrees to the reinforcing fibers; substantially all the reinforcing fibers are divided with the notches; and the length L of the reinforcing fibers divided with the notches is in a range of 10 to 100 mm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is excellent in handleability and shape followability to complex shapes, can be molded in a short time, and, when made into fiber reinforced plastic, has excellent mechanical properties applicable to structural materials, its low variation, In particular, the present invention relates to an intermediate substrate that exhibits dimensional stability and a method for producing the same. More specifically, for example, the present invention relates to a laminated base material that is an intermediate base material of fiber reinforced plastic suitably used for aircraft members, automobile members, sports equipment, and the like, and a manufacturing method thereof.

  As a method of molding fiber reinforced plastic having high functional properties, a semi-cured intermediate base material impregnated with thermosetting 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 thermosetting resin is cured to form a fiber reinforced plastic, is most commonly performed. In recent years, for the purpose of improving production efficiency, RTM (resin transfer molding) molding in which a continuous fiber base previously shaped into a member shape is impregnated with a thermosetting resin and cured has been performed. The fiber reinforced plastics obtained by these molding methods have excellent mechanical properties because they are continuous fibers. Further, since the continuous fibers are regularly arranged, it is possible to design the mechanical properties required by the arrangement of the base material, and the variation in the mechanical properties is small. However, 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 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. Further, since a thermosetting resin is used, there is a problem that a chemical reaction is involved at the time of molding and a molding time is required.

In order to fill the disadvantages of the above materials, by cutting into a prepreg made of continuous fiber and thermoplastic resin, it can be molded for a short time, and exhibits excellent shape following at the time of molding, Have been disclosed (for example, Patent Documents 1 and 2). However, although mechanical characteristics are higher than SMC and variation thereof is small, it cannot be said that the strength is sufficient for application as a structural material. Compared with a 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. Furthermore, since the prepreg of the thermoplastic resin has no tack, there is a problem that it is not integrated only by being laminated and molding is difficult.
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 is excellent in handleability and shape followability to a complicated shape, can be molded in a short time, and can be applied to a structural material in the case of a fiber reinforced plastic. It is an object to provide an intermediate base material that exhibits excellent mechanical properties, such as low variability, excellent dimensional stability, and a method for producing the same.

The present invention employs the following means in order to solve such problems. That is,
(1) A prepreg layer composed of a plurality of reinforcing fibers oriented in one direction and a thermoplastic resin is a flat laminated base material which is integrated in two or more directions, and the entire surface of the prepreg layer The absolute value of the angle Θ formed with the reinforcing fiber has a linear cut in the range of 2 to 25 °, and substantially all the reinforcing fibers are cut by the cut and cut by the cut. The laminated base material whose fiber length L of a reinforced fiber exists in the range of 10-100 mm.

  (2) The laminated base material according to (1), wherein the cut has a projection length Ws projected in the vertical direction of the reinforcing fiber within a range of 30 μm to 1.5 mm.

  (3) The laminated base material according to (1) or (2), wherein the prepreg layer is laminated in a pseudo isotropic manner.

  (4) The laminated substrate according to any one of (1) to (3), wherein a thermoplastic resin is unevenly distributed between the layers of the laminated substrate.

  (5) The laminated base material according to (4), wherein the central portion in the thickness direction of the prepreg layer is composed of only reinforcing fibers.

  (6) The laminated substrate according to any one of (1) to (4), wherein a void ratio of the laminated substrate is 2% or less.

  (7) The laminated base material according to any one of (1) to (5), wherein the prepreg layers are integrated in a dot shape.

  (8) A composite laminated substrate in which a nonwoven fabric made of reinforcing fibers is arranged on at least one surface of the laminated substrate according to any one of (1) to (7).

  (9) A fiber reinforced plastic obtained by molding the laminated base material according to any one of (1) to (7) or the composite laminated base material according to claim 8 into a three-dimensional shape.

  (10) A linear notch is provided on the entire surface of the prepreg base material composed of reinforced fibers and thermoplastic resin oriented in one direction so that the absolute value of the angle Θ between the reinforced fibers is in the range of 2 to 25 °. , Substantially all the reinforcing fibers are divided by the incision, the fiber length L of the reinforcing fibers divided by the incision is set within a range of 10 to 100 mm to form a notched prepreg base material, and the notched prepreg base A method for producing a laminated base material, comprising: laminating a plurality of materials and heating and pressing the laminated cut prepreg base material until the predetermined void ratio is reached.

  (11) The method for producing a laminated base material according to (10), wherein the prepreg base material is one in which a thermoplastic resin is unevenly distributed and impregnated only on the surface of reinforcing fibers oriented in one direction.

  (12) The method for producing a laminated base material according to (10), wherein the prepreg base material has a void ratio of 1% or less.

  (13) A fiber sheet is formed by aligning reinforcing fibers in one direction in a flat shape, a nonwoven fabric made of a thermoplastic resin is sandwiched from both sides of the fiber sheet, and the fiber sheet is impregnated with the prepreg base. The manufacturing method of the laminated base material in any one of Claims (10)-(12) which produces a material.

  (14) The cutting prepreg base material is formed by cutting into a predetermined outer shape at the same time as inserting the notch using a punching die for inserting the notch into the entire surface of the prepreg base material. )-(13) The manufacturing method of the laminated base material in any one of.

  (15) In laminating a plurality of the cut prepreg base materials to form a laminated base material, a laminated base material is laminated so as to include the cut prepreg base materials having different outer shapes, and a laminated base material having a portion having a different laminated thickness The manufacturing method of the laminated base material in any one of (10)-(14) to form.

  (16) The laminated base material according to any one of (1) to (7) or the composite laminated base material according to (8) is softened by heating and then cold-pressed to obtain a three-dimensional fiber reinforced plastic. A method for producing a fiber-reinforced plastic.

  (17) The method for producing a fiber-reinforced plastic according to (16), wherein the peripheral part of the laminated base material is gripped and then molded by pressing a molding die against a central part of the laminated base material.

  (18) The production of a fiber reinforced plastic according to (16), wherein the laminated base material smaller than the mold cavity is disposed in a cavity of the mold, and the laminated base material is stretched to form a fiber reinforced plastic. Method.

  (19) The method for producing a fiber-reinforced plastic according to any one of (16) to (18), wherein pressurization and decompression are repeated in the cold press.

  According to the present invention, it is excellent in handleability, shape followability to a complicated shape, can be molded in a short time, and when made into a fiber reinforced plastic, it has excellent impact resistance applicable to structural materials. It is possible to obtain an intermediate base material that exhibits mechanical properties, its low variation, and excellent dimensional stability, and a method for producing the same.

  The present inventors have excellent handling properties, conformability to complicated shapes, can be molded in a short time, and when made into fiber reinforced plastic, have excellent mechanical properties, low variation, and excellent dimensional stability. In order to obtain an intermediate base material that expresses the prepreg base material, a specific cutting pattern is inserted into the prepreg base material composed of reinforcing fibers oriented in one direction and a thermoplastic resin. By making the prepreg base material, laminating the cut prepreg base material, heating and pressurizing (repeating pressurization and depressurization as necessary), and by integrating it into a specific laminated base material, this is required. They found out that they could solve the problem all at once. In addition, the prepreg base material used in the present invention is a state in which the resin sheet is not completely impregnated in the fiber in addition to the reinforced fiber oriented in one direction or the base material in which the resin is completely impregnated in the reinforcing fiber base material. And a resin semi-impregnated base material (semi-preg: hereinafter, sometimes referred to as semi-impregnated prepreg). In the present specification, unless otherwise specified, in the term including fibers or fibers (for example, “fiber direction”), the fibers represent reinforcing fibers. In the present specification, the continuous fiber refers to a reinforcing fiber having a fiber length of 100 mm or more.

  The longer the reinforcing fiber in the intermediate base material, the better the mechanical properties, but the reinforcing fiber is stretched during molding and it is difficult to stretch in the fiber orientation direction, resulting in inferior shape conformability (hereinafter referred to as fluidity) to a complicated shape. . For this reason, it was considered that both the mechanical properties and the fluidity can be achieved by setting the fiber length of the reinforcing fibers in the intermediate base material within a predetermined range.

  In addition, since the single yarn of reinforcing fiber has a cross-sectional shape (generally a circular shape) extruded (generally a cylindrical shape), the fiber orientation of adjacent reinforcing fibers is aligned due to geometric constraints Easy to fill. In general, the higher the fiber content of the reinforcing fibers, the easier it is to improve the mechanical properties. For example, Vf remains at most 40% in a randomly oriented substrate such as SMC, while a unidirectional sheet substrate such as a prepreg. The fiber volume content Vf of the maximum reaches 70%. Furthermore, in a base material randomly oriented such as SMC, stress concentration is likely to occur at a site where the reinforcing fibers are aggregated stochastically, and there is a possibility of breaking at a strength much lower than the potential of the material. On the other hand, a laminated base material obtained by laminating a unidirectional sheet base material with another unidirectional sheet base material having a different fiber orientation hardly transmits cracks to adjacent layers, and the strength is easily improved. Therefore, from the viewpoint of mechanical properties, it is preferable to use a laminated base material in which unidirectional sheet base materials are laminated as an intermediate base material.

  In addition, a fiber reinforced plastic having excellent impact resistance can be obtained by using a thermoplastic resin as the matrix resin used for the intermediate substrate. That is, in the case of a fiber reinforced plastic using discontinuous reinforcing fibers, a thermoplastic resin generally having a higher toughness value than a thermosetting resin is used as a matrix resin in order to break the fiber ends so as to connect each other. As a result, strength, particularly impact resistance, is improved. In some cases (for example, leading edge) of aircraft members that require impact resistance, carbon fiber and polyphenylene sulfide fiber reinforced plastics are used. Furthermore, in obtaining a fiber reinforced plastic by molding the intermediate substrate into a three-dimensional shape, the thermoplastic resin is not accompanied by a chemical reaction, and the shape is determined by cooling and solidifying, so it can be molded in a short time, Excellent productivity.

  On the other hand, when laminating a prepreg of a thermoplastic resin having no tack, integration is difficult. In molding a three-dimensional fiber reinforced plastic, the prepreg group which is not integrated is not easy to handle, and it is difficult to accurately position and arrange it directly on the mold. In particular, when molding a thick fiber-reinforced plastic, it takes time and labor to stack, and productivity is lowered. Since fiber reinforced plastic used as a structure is generally molded not only in one direction but also in a predetermined symmetrical laminate such as cross-ply or pseudo-isotropic, a flat laminated substrate having a predetermined laminated configuration is preliminarily formed. By preparing it, the productivity of fiber reinforced plastics will be dramatically improved.

  In summary, in the present invention, a prepreg layer composed of a cut prepreg base material made of a reinforced fiber and a thermoplastic resin having a fiber length oriented in one direction within a predetermined range is oriented in two or more directions. By providing an integrated flat plate-like laminated base material as an intermediate base material, it is excellent in handleability, shape followability to complex shapes, can be molded in a short time, and is made into fiber reinforced plastic Excellent mechanical properties such as impact resistance applicable to structural materials, low variation, and excellent dimensional stability can be exhibited. FIG. 8 shows an example of the laminated base material of the present invention in which a prepreg layer is formed on [45/0 / −45 / 90].

  Furthermore, in the present invention, the prepreg layer needs to have the following configuration in order to achieve both fluidity and mechanical properties at a high level.

  The prepreg layer according to the present invention is composed of reinforcing fibers oriented in one direction and a thermoplastic resin, and the entire surface is provided with cuts in the range of an angle Θ between the reinforcing fibers of 2 to 25 °. , Substantially all of the reinforcing fibers are divided by cutting, and the fiber length L divided by the cutting is in the range of 10 to 100 mm. In the present invention, “substantially all of the reinforcing fibers are divided by the cut” means that the area where the continuous fibers not cut by the cut of the present invention are oriented accounts for the area of the prepreg layer. Of less than 5%.

  In the present invention, the fiber length L is an incision closest to the fiber direction in which an arbitrary incision and an incision equivalent to the arbitrary incision have a projected length Ws projected in the vertical direction of the reinforcing fiber. It refers to the length of the fiber that is divided by (a pair of cuts). Here, the “projection length Ws projected by the cut in the vertical direction of the reinforcing fiber” is the vertical direction of the reinforcing fiber (fiber vertical direction 2) in the plane of the prepreg layer as shown in FIG. Is the projection plane, and refers to the length 9 when projected perpendicularly to the projection plane (fiber orientation direction 1). Cutting is inserted in the entire surface of the prepreg layer, and by making the fiber length L of the reinforcing fibers in the substrate all 100 mm or less, the fibers can flow at the time of molding, particularly in the fiber orientation direction. Excellent shape followability to shape. When there is no notch, that is, when only continuous fibers are used, a complicated shape cannot be formed because the fibers do not flow in the fiber orientation 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 shorter than the fiber length L that is cut and divided in addition to the pair of cuts, but the fewer the fibers of 10 mm or less, the better. More preferably, the area in which fibers of 10 mm or less are oriented is smaller than 5% of the ratio of the area of the prepreg layer.

  Even if the thickness H of the prepreg layer is larger than 300 μm, good fluidity can be obtained. However, since the prepreg layer according to the present invention has a cut, the strength decreases as the divided layer thickness increases. If there is a tendency and it is assumed to be applied to a structural material, it is preferable 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 difficult to stably form an extremely thin prepreg layer, the effect of the present invention can be obtained at low cost. Is preferably 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%, it is difficult to obtain the high mechanical properties required for the structural material. Considering the relationship between fluidity and mechanical properties, it is more preferably in the range of 55-60%.

  In addition, 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 is 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 more than 2 ° If it is smaller, at least the shortest distance between the cuts becomes smaller than 0.9 mm, making it difficult to insert the cuts. 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, an example of a preferable cutting pattern will be described with reference to FIGS.

  The reinforcing fibers have a plurality of cuts 4 controlled and aligned on the prepreg layer oriented in one direction. The fibers are divided by the notches 4 that form pairs in the fiber orientation direction, and the interval 6 is set to 10 to 100 mm, so that substantially all the reinforcing fibers on the prepreg layer have a fiber length L of 10 to 100 mm. be able to. The phrase “substantially all of the reinforcing fibers are divided by the incision” means that 95% or more of the reinforcing fibers included in the prepreg layer are 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 layer having five different cutting patterns. The prepreg layer 7 in FIG. 4 a) has skewed continuous, straight cuts 4 arranged at equal intervals. The prepreg layer 7 of FIG. 4b) has skewed continuous, straight cuts arranged at two intervals. The prepreg layer 7 in FIG. 4c) has continuous, curved (meandering) cuts 4 arranged at equal intervals. The prepreg layer 7 of FIG. 4d) has intermittent linear cuts 4 arranged at equal intervals and skewed in two different directions. The prepreg layer 7 of FIG. 4e) has skewed intermittent linear cuts 4 arranged at equal intervals. The incision 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. Further, the length L of the reinforcing fiber divided by the cutting 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 varies. Can be further suppressed, 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 made as shown in FIG. 1 and FIGS. 4a) to 4c). In the pattern of Example [1], since the cut 4a is not intermittent, flow turbulence does not occur near the cut end, and all the fiber lengths L should be constant in the region where the cut 4a is inserted. The flow is stable. Since the notches 4a are continuously formed, it is difficult to handle the prepreg alone, and it is preferable to use it as a laminated base material.

Moreover, as another preferable example [2], as shown in FIG. 2, when the length 9 projected in the vertical direction of the reinforcing fiber is Ws, the intermittent cuts 4b in which Ws is in the range of 30 μm to 100 mm are provided. The prepreg layer 7 is provided on the entire surface, and the notch 4b ₁ and the notch 4b ₂ adjacent to the notch 4b ₁ in the fiber orientation 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 prepreg layer. That is, if there is a fiber that is not cut by cutting, the fluidity of the base material is remarkably lowered. However, if a large amount of cutting is made, there is a problem that a portion where L is less than 10 mm appears. Conversely, when Ws is greater than 10 mm, the strength is almost constant. That is, when the number of fibers to be divided 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 overlaps by translating in the fiber direction. The fiber 8 is stably separated by the presence of the width 8 where the fibers are divided by the adjacent notches with a fiber length shorter than the fiber length L which is divided by the notches 4b which are paired in the fiber direction. The prepreg layer 7 can be manufactured with a length of 100 mm or less. 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 °, an extremely small cut of 1.5 mm or less is industrially applied. It can be provided stably. 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.

  A fiber formed by laminating a plurality of prepreg layers having the above-described configuration, and aligning and integrating the fiber directions in at least two directions to form a flat laminated substrate, following the shape of a complicated shape, or stretching the shape. The site | part to which the reinforced plastic applied the prepreg layer has the following characteristics. A plurality of cut fiber openings formed on the entire surface of the short fiber layer constituting the fiber reinforced plastic, which are formed of only the thermoplastic resin or the reinforcing fiber of the adjacent layer without the presence of the reinforcing fibers, The fiber length L of the reinforcing fiber is divided within a range of 10 to 100 mm, and the surface area of the cut opening at the surface of the short fiber layer is within a range of 0.1 to 10% of the surface area of the short fiber layer. That is, one of the major features of the present invention is that the cut portion of the prepreg layer does not open by molding.

  This feature will be described with reference to FIGS. As a comparison with the present invention, FIG. 5 shows a laminated base material 10 composed of a prepreg layer 7 having an absolute value of 90 ° of the angle Θ between the notch 4 and the fiber 3 a), and the laminated base material 10 is stretched. The fiber reinforced plastic 11 molded in this manner is shown in b) in which a prepreg layer 7 and a short fiber layer 12 derived from the prepreg layer 7 are respectively shown in a close-up plan view and a cross-sectional view taken along the line AA of the plan view. As shown to a), the prepreg layer 7 has the notch perpendicular | vertical to a fiber on the whole surface, and the notch 4 has penetrated 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 laminated base material 10 can be easily obtained by press molding or the like (however, the thickness is reduced). . When the stretched fiber reinforced plastic 11 is obtained as in b), the short fiber layer 12 derived from the prepreg layer 7 stretches in the fiber vertical direction, and a region (cut opening) 13 in which no fiber exists is generated. Is done. 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, from the laminated base material 10 of 250 × 250 mm. When the fiber reinforced plastic 11 having a size of 300 × 300 mm is obtained, the total area of the cut openings 13 is 50 × 300 mm, that is, 1/6 (about 16.6) with respect to the surface area of the fiber reinforced plastic 11 having a size of 300 × 300 mm. 7%) is 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. Accordingly, when the laminated base material 10 is stretched and molded, the undulation 17 of the layer and the resin rich portion 16 are generated at the fiber bundle end portion 15, which affects the deterioration of the mechanical properties and the surface quality. 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, in FIG. 6, a laminated base material 10 composed of the prepreg layer 7 of the preferred example [1] of the present invention is shown in a), and a fiber reinforced plastic 11 formed by stretching the laminated base material 10 is shown in b). A cross-sectional view of the prepreg layer 7 and the short fiber layer 12 derived from the prepreg layer 7 in close-up and a cross-sectional view taken along the line AA of the plan view are shown. As shown to a), the prepreg layer 7 has the continuous cut 4a whose absolute value of angle (THETA) formed with the fiber 3 is 25 degrees or less, and the cut 4a has penetrated 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 laminated substrate 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 prepreg layer 7 stretches in the fiber vertical direction, and the fiber 3 itself rotates 18 to gain an area of the stretched region. Therefore, as shown in FIG. 5, a region (cut opening) 13 where no fiber exists is not substantially generated, and the area of the cut fiber opening 12 on the surface of the short fiber layer 12 is compared with the surface area of the short fiber layer 12. In the range of 0.1 to 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 having no 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 It can be obtained for the first time by being put continuously. 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 when it is below °.

  In FIG. 7, a laminated base material 10 composed of the prepreg layer 7 of the preferred example [2] of the present invention is shown in a), and a fiber reinforced plastic 11 formed by stretching the laminated base material 10 is shown in b). The top view which closed up the prepreg layer 7 and the short fiber layer 12 derived from the prepreg layer 7 was shown. As shown in a), the prepreg layer 7 has intermittent cuts 4b whose absolute value of the angle Θ between the fibers 3 is 25 ° or less, and the cuts 4b penetrate through the thickness direction of the layer. Yes. By making the fiber length L 100 mm or less over the entire surface of the prepreg layer 7 by the cuts 4b, the fluidity is ensured, and the fiber reinforced plastic 11 whose area is easily extended from the laminated base material 7 is obtained by press molding or the like. be able to. By reducing the cut length and the cut angle, the projection 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 prepreg layer 7 does not stretch in the fiber direction when stretched in the fiber vertical direction. The (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 becomes remarkable particularly 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 cut opening Compared with the surface area of the short fiber layer 12, the area in the surface of the short fiber layer 12 can be 0.1 to 10% of range. 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 the flow in the vertical direction of the fiber to obtain a fiber reinforced plastic having no layer undulation is that the absolute value of the cut angle Θ is 25 ° or less and the cut is made of the reinforcing fiber. It can be obtained for the first time when the projection length Ws projected in the vertical direction is 1.5 mm or less. More preferably, when Ws is 1 mm or less, higher strength and higher quality can be achieved.

  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 prepreg layer of the present invention include organic fibers such as aramid fiber, polyethylene fiber, polyparaphenylene benzoxador (PBO) fiber, glass fiber, carbon fiber, silicon carbide fiber, alumina fiber, and Tyranno. Examples thereof include inorganic fibers such as fibers, basalt fibers, and ceramic fibers, metal fibers such as stainless fibers and steel fibers, and other reinforcing fibers using 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 thermoplastic resin used in the prepreg layer of the present invention include polyamide (PA), polyacetal, polyacrylate, polysulfone, ABS, polyester, acrylic, polybutylene terephthalate (PBT), polycarbonate (PC), and polyethylene terephthalate. (PET), polyethylene, polypropylene, polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyetherimide (PEI), polyetherketone (PEK), liquid crystal polymer, vinyl chloride, polytetrafluoroethylene and other fluorine-based resins And silicone. Furthermore, PA, PPS, PEEK, PEI, and PEK are preferable in view of adhesiveness with reinforcing fibers and mechanical properties as a matrix resin. Furthermore, PEEK is preferable when particularly high mechanical properties are required for the fiber reinforced plastic, and PA and PPS are preferable when low cost is required.

  When the fiber direction of the prepreg layer is oriented in only one direction, the laminated base material of the present invention flows only in the fiber vertical direction. That is, since the flow of the thermoplastic resin in the 90 ° direction is a driving force for moving the reinforcing fibers, fluidity is manifested only when the fibers are aligned and integrated in two or more directions. If the fiber orientation is different between the prepreg layers, a difference occurs in the flow direction and distance for each prepreg 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 of the configuration in which the thermoplastic 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.

Furthermore, since the prepreg layer according to the present invention has a cut on the entire surface, air trapped at the time of lamination is easily degassed through the cut in the thickness direction, voids are hardly generated, and high mechanical properties can be expected. Among them, quasi-isotropic lamination such as [+ 45/0 / −45 / 90] _S and [0 / ± 60] _S is preferable in order to obtain 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 is an intermediate base material with little fluidity variation and excellent robustness. Further, when the laminated base material of the present invention is formed into a fiber reinforced plastic used as a structural material by molding, it is necessary to withstand loads from multiple directions. From the viewpoint of fluidity and mechanical properties, the laminated base material of the present invention is preferably laminated in a pseudo isotropic manner to withstand general use.

  In the laminated base material of the present invention, the thermoplastic resin may be unevenly distributed between the prepreg layers. As described above, by making the thermoplastic resin unevenly distributed between the layers, the fluidity is improved even if the fiber deposition content Vf is high. In general, fiber reinforced plastics with a laminated structure are prone to delamination when an impact load is applied from the outside, but thermoplastic resin that is not restrained from displacement by the reinforced fibers is unevenly distributed between the layers. Thus, the strain gap between layers can be absorbed, and delamination hardly occurs. As a result, even when an impact load is applied, the mechanical properties of the fiber reinforced plastic are hardly lowered and the impact resistance is excellent. If too much thermoplastic resin is unevenly distributed between the layers, the fiber deposition content Vf of the entire fiber reinforced plastic is lowered, so that the elastic modulus is lowered. The resin deposition content Vim of the unevenly distributed thermoplastic resin is preferably 5% or less.

  As shown in the cross-sectional view of the prepreg layer in FIG. 10, in the laminated base material of the present invention, the central portion 21 in the thickness direction of the prepreg layer to be formed may be composed only of reinforcing fibers. Near the surface of the prepreg layer is impregnated with a thermoplastic resin, and the thermoplastic resin may be unevenly distributed between the prepreg layers, laminated in a semi-impregnated state, as a laminated substrate, If impregnated completely, there is no problem as a mechanical property of the fiber reinforced plastic.

  On the other hand, the laminated base material of the present invention may have a void ratio of 2% or less. The fiber reinforced plastic is molded by using a laminated base material in which the thermoplastic resin is completely impregnated in the reinforced fiber, and there is almost no void. And mechanical properties are greatly improved. In the present invention, the void ratio is determined from the relationship between the volume and weight of the test specimen (here, the laminated base material) in water. Since the thermoplastic resin easily absorbs moisture, the measurement is performed after storing in a desiccator for one day or more. First, after measuring the weight of the test body, the volume of the test body is measured by immersing the test body in water in a container and measuring the volume increase. On the other hand, the ideal specific gravity of the test specimen is calculated by multiplying the respective volume contents of the fiber and resin forming the specimen and the specific gravity of the fiber and resin. The volume of the test specimen expected from the weight of the measured specimen divided by the ideal specific gravity is smaller than the volume of the measured specimen, and the difference is the void volume. The void ratio (the void volume content) is obtained by dividing the void volume by the measured specimen volume. In order for the fiber reinforced plastic to stably exhibit mechanical properties, the void ratio is more preferably 1% or less.

  In the laminated base material of the present invention, the prepreg layers may be fused on the entire surface of the interlayer. By fusing all over the interlayer, the handleability is improved, the void ratio can be reduced, and the mechanical properties are improved. On the other hand, only a part of the prepreg layers may be fused (spot welded) in a spot shape using a laser or a soldering iron. When integrating prepreg layers by fusing in a dot shape, the process of integrating as a laminated substrate can be shortened while improving the handleability so that the laminated substrate does not fall apart during molding There are benefits.

  More preferably, a composite laminated base material in which a nonwoven fabric made of reinforcing fibers is arranged on at least one surface of the laminated base material of the present invention is preferable. Since the surface is in contact with the mold during molding, the flow tends to be disturbed. When the prepreg layer in which the reinforcing fibers are oriented in one direction appears on the surface of the fiber reinforced plastic, the dripping of the fibers becomes noticeable at the R portion where the shape change is large. Therefore, the surface quality is remarkably improved by arranging a nonwoven fabric composed of reinforcing fibers randomly oriented in advance on the surface of the laminated base material. Moreover, since a nonwoven fabric is comprised from a reinforced fiber, the fall of a mechanical characteristic can be minimized. Preferably, the reinforcing fibers used in the nonwoven fabric are the same as the reinforcing fibers used in the prepreg layer. Furthermore, it is preferable that the nonwoven fabric made of reinforcing fibers can flow in accordance with the extension of the prepreg layer, and the fiber length is preferably in the range of 3 to 15 mm.

  The laminated base material and composite laminated base material of the present invention are preferably formed into a three-dimensional shape to be a fiber reinforced plastic. In particular, when manufacturing fiber-reinforced plastics with complex shapes, the laminate or composite laminate substrate of the present invention on a flat plate can be easily stretched simply by placing it in a mold, and pressure is applied in general press molding. Even a difficult standing surface can be suitably filled.

  As a method for producing a laminated base material of the present invention, the absolute value of the angle Θ formed with the reinforcing fiber is within the range of 2 to 25 ° on the entire surface of the prepreg base material composed of the reinforcing fiber and the thermoplastic resin oriented in one direction. A straight notch is formed, substantially all the reinforcing fibers are divided by the incision, and the fiber length L of the reinforcing fiber divided by the incision is set within a range of 10 to 100 mm. A plurality of the cut prepreg base materials are laminated, and the laminated cut prepreg base materials are integrated by heating and pressurizing to form a laminated base material. As a method of manufacturing a laminated base material having a predetermined shape, there are a method of cutting the prepreg base material before and after inserting a cut into the entire surface of the prepreg base material, and a method of cutting the laminated base material itself.

  As a method for inserting the cut into the prepreg base material, first, a prepreg base material of continuous fibers oriented in one direction is prepared, and then the cut is made by manual operation using an cutter or an automatic cutting machine, or one In the prepreg manufacturing process of continuous fibers oriented in the direction, a rotating roller with blades arranged at predetermined positions is continuously pressed, or a prepreg base material is stacked on multiple layers and pressed with a mold with blades arranged at predetermined positions, etc. There is a way. 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 fiber to be cut per unit length of the blade is reduced, and the fiber can be cut with a small force. Can be improved. 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 if Ws is small (specifically, 1 mm or less).

  In producing the laminated base material of the present invention, the absolute value of the angle Θ formed with the reinforcing fiber is within the range of 2 to 25 ° on the entire surface of the prepreg base material composed of the reinforcing fiber and the thermoplastic resin oriented in one direction. A linear incision is provided, substantially all the reinforcing fibers are divided by the incision, and the fiber length L of the reinforcing fibers divided by the incision is set within a range of 10 to 100 mm to form a incised prepreg base material. In addition, when a plurality of the cut prepreg base materials are stacked and the stacked cut prepreg base materials are heated, it is preferable to repeat the pressurization and pressure reduction until a predetermined void ratio is obtained. By repeating pressurization and pressure reduction using a double belt press or the like, the voids in the laminated base material are filled with the thermoplastic resin. More preferably, finally, the void content of the laminated base material is set to 2% or less in volume content to obtain a fiber-reinforced plastic that is difficult to delaminate and has excellent strength and impact resistance. it can.

  In the production of the laminated base material of the present invention, it is preferable to use a prepreg base material in which a thermoplastic resin is unevenly distributed and impregnated only on the surface of reinforcing fibers oriented in one direction. The thermoplastic resin has a high resin viscosity even when heated, and the resin is not easily impregnated into the reinforcing fiber. Therefore, a semi-impregnated prepreg base material (semi-preg) can be manufactured at a lower cost than a fully impregnated prepreg base material. Instead of completely impregnating one by one at the stage of the prepreg base material, it may be impregnated together at the stage of laminating a plurality of cut prepreg base materials.

  On the other hand, when manufacturing the laminated base material of the present invention, a prepreg base material having a void ratio of 1% or less may be used as the prepreg base material. Lamination of a substantially completely impregnated prepreg base material is preferable because a laminated base material having a low void ratio can be efficiently produced.

  In preparing the prepreg base material, reinforcing fibers are drawn in one direction to form a fiber sheet, a nonwoven fabric made of a thermoplastic resin is sandwiched from both sides of the fiber sheet, and the thermoplastic resin is made into a fiber by heating and pressing. It is better to impregnate the sheet. Although a resin film made of a thermoplastic resin may be used, the use of a nonwoven fabric can be deaerated also in the out-of-plane direction, and a prepreg base material having a low void ratio can be created. In addition, the fiber sheet is impregnated with a reactive resin having a low molecular weight component and then polymerized to obtain a thermoplastic resin, or the fiber sheet is impregnated with a thermoplastic resin that has been dissolved in a solvent to reduce the viscosity, and then the solvent is removed. Thus, a prepreg base material may be created.

  When inserting a notch into a prepreg base material and cutting it into a predetermined outer shape, use a punching die that inserts a cut into the entire surface of the prepreg base material, and simultaneously cutting the cut into a predetermined outer shape. A cut prepreg base material is preferably formed. By carrying out the insertion of the cut and the cutting of the outer shape at the same time using the same punching die, a cut prepreg base material used for lamination can be created in a short time and at a low cost.

  When laminating a plurality of cut prepreg base materials, the cut prepreg base materials may be laminated to the same thickness over the entire surface, but they are laminated so as to include cut prepreg base materials having different outer shapes. You may form the laminated base material which has a location from which thickness differs. By making the laminated thickness different depending on the location at the stage of the laminated substrate in advance, it is not necessary to forcefully flow in the thickness direction when molding the fiber reinforced plastic with different thickness depending on the location, so there is less layer undulation in the thickness direction, A desired form of high-quality fiber reinforced plastic can be realized.

  In manufacturing a fiber reinforced plastic using the laminated base material or composite laminated base material of the present invention, the laminated base material or composite laminated base material is softened by heating and then cold-pressed to obtain a three-dimensional fiber reinforced plastic. It is good to mold. The process of heating and softening the laminated base material or composite laminated base material and the process of cold pressing are performed in separate devices. For example, the former uses an IR heater, and the latter uses a press set with a temperature-controlled mold. The fiber reinforced plastic can be manufactured without raising or lowering the temperature of the mold, and the molding cycle can be accelerated. It is also possible to obtain a fiber-reinforced plastic having a desired shape without using a trimming die as a biting die.

  In producing the fiber reinforced plastic of the present invention, it is preferable to mold (draw molding) by pressing a molding die against the central portion of the laminated base material after gripping the peripheral portion of the laminated base material of the present invention. Since the flat laminated substrate can be stretched and formed entirely without wrinkling, it is easy to control the forming. Further, it has a feature that it is easy to form a deep standing surface that is difficult to apply pressure during conventional molding.

  In producing the fiber reinforced plastic of the present invention, the laminated base material of the present invention which is smaller than the mold cavity is placed in the mold cavity, and the laminated base material is stretched to form the fiber reinforced plastic (charge molding). May be. Since the laminated substrate can be stretched, filled and molded, it is not necessary to cut the laminated substrate on a complicated outer shape, and the cost is low. Even a flat laminated substrate has a feature that it can be formed by filling standing surfaces and ribs.

  In producing the fiber reinforced plastic of the present invention, it is preferable to repeatedly pressurize and depressurize with a cold press. By repeating pressurization and depressurization, it is easy to deaerate through the layers of the notch and the prepreg layer, and the void ratio can be reduced.

  The assembly cost can be reduced by embedding a metal insert in the laminated base material of the present invention so as to have a mechanism such as a rotating part and integrating it at the time of molding. 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, as a use of the laminated base material of the present invention and fiber reinforced plastic molded using the same, the shaft, head, leading edge, and the like of sports parts such as bicycle equipment and golf that require strength, rigidity, and lightness are required. There are aircraft parts such as window frames, automobile parts such as doors and seat frames, and mechanical parts such as robot arms. In particular, in addition to strength and light weight, it can be preferably applied to aircraft members that require impact resistance and automobile members that require productivity.

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

Example 1
Carbon fiber (tensile strength 4,900 MPa, tensile elastic modulus 235 GPa) is aligned in one direction to form a fiber sheet having a basis weight of 125 g / m ^2, and copolymer polyamide resin (Toray Industries, Inc. ) “Amilan” (registered trademark) CM4000 manufactured by Polyamide 6/66/610 copolymer, melting point 155 ° C.) with a fabric weight of 40 g / m ² sandwiched between them and heated and pressed through a calender roll many times. By impregnating the resin into the fiber sheet, a prepreg base material having a fiber deposition content Vf of 50% and a thickness of 0.14 mm was prepared. After leaving this prepreg base material in a vacuum oven for one day, a part is cut out and weighed, and immersed in water to measure the volume. The specific gravity of carbon fiber 1.8 g / cm ³ and the specific gravity of resin 1 When the void ratio estimated from .14 g / m ² was measured, the void volume content was 0.8%.

  In this prepreg base material, the die obtained by NC machining of the metal in the carbon fiber orientation direction (0 ° direction) and the direction shifted 45 degrees to the right from the carbon fiber orientation direction (45 ° direction), respectively. Press to form a rectangular outer shape of 150 × 150 mm and a straight cut in the direction of 10 ° from regular fibers at equal intervals as shown in FIG. An embedded prepreg base material was obtained. The fiber length L divided by the cutting is 30 mm. The projected length Ws projected in the vertical direction of the cut fiber is 0.17 mm (actual cut length is 1 mm), and the fiber length L or less (this time is about 15 mm) due to the adjacent cut as shown in FIG. ) Was parted.

The obtained cut prepreg base material has no tack, and 16 layers are stacked in a pseudo-isotropic manner ([45/0 / -45 / 90] _2S ), and soldering irons are provided at the four corners of the laminated cut prepreg base material group. It pressed and spot-welded and integrated and the flat laminated base material was created.

  The flat laminated substrate thus obtained was left in a vacuum oven for one day, and then a C-type fiber reinforced plastic (height of standing surface 30 mm) was produced by a cold press as shown in FIG. First, the laminated substrate was placed in an oven and heated, and when the surface temperature reached 200 ° C., the laminate was taken out from the oven. The heated laminated substrate was arranged so as to be quickly pushed into the female mold 20 having a 100 × 100 mm cavity. Both the male mold 19 and the female mold 20 are temperature-controlled at 70 ° C., and the male mold 19 is pressed against the laminated base material arranged in the female mold 20 and held for 1 minute under a pressure of 6 MPa by a press. And then demolded.

  The obtained fiber reinforced plastic was filled to every corner of the mold and showed good fluidity. Since the surface area was larger than the laminated substrate, the thickness of the fiber reinforced plastic was lower than that of the bulky laminated substrate. When the cross section was observed, the laminated structure was maintained up to the end portion of the standing surface, and the R portion was also a laminated structure having a substantially uniform thickness. Thus, the epoch-making effect that the laminated structure of the laminated base material was preserved even when the shape was followed to a complicated shape was found. Therefore, it was presumed that by using the laminated base material of the present invention, even if the shape of the fiber reinforced plastic is complicated, it is possible to design using the physical properties of the flat plate without changing the mechanical characteristics depending on the place.

(Example 2)
While feeding the same prepreg base material as in Example 1 in the fiber direction, a cutting die in which blade-like sewing blades with cut portions and uncut portions arranged at intervals of 1 mm are arranged and embedded in a wooden mold at an angle of 10 ° is used. By pressing, a linear notch in the direction of 10 ° was intermittently inserted from the fiber as shown in FIG. 4e) to the entire surface to create a notched prepreg base material and wound around a roll. The fiber length L divided by the cutting is 30 mm. The projected length Ws projected in the vertical direction of the cut fiber is 0.17 mm (actual cut length is 1 mm), and the fiber length L or less (this time is about 15 mm) due to the adjacent cut as shown in FIG. ) Was parted. After leaving this cut prepreg base material in a vacuum oven for one day, the cut prepreg base material was unwound from a plurality of rolls to form a 16-layer pseudo-isotropic ([45/0 / −45 / 90] _2S ) While being laminated in a sheet form, pressurization and depressurization were repeated while heating with a double belt press, and the cut prepreg base materials were fused and integrated on the entire surface to obtain a laminated base material.

  The obtained laminated substrate was left in a vacuum oven for 1 day, and then the weight was measured, the volume was measured by immersing in water, and the void ratio was measured. The volume content of the void was 0.7%. there were. Since the cuts were inserted in the entire surface of the cut prepreg base material, it was presumed that the void ratio was reduced because it was easy to deaerate out of the surface.

  The laminated base material was cut into a size of 250 × 250 mm, left in a vacuum oven for 1 day, and then cold pressed. First, the laminated substrate was placed in an oven and heated, and when the surface temperature reached 200 ° C., the laminate was taken out from the oven. Next, after placing it at the approximate center on a flat plate mold temperature controlled to 70 ° C. having a 300 × 300 mm cavity, it was held for 1 minute under pressure of 6 MPa by a press machine, cooled, and demolded. A 300 × 300 mm flat fiber-reinforced plastic 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 is no warpage as a whole, 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 and smoothness are maintained. It was.

  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. An Instron (registered trademark) universal testing machine type 4208 was used as a testing machine. The number of test pieces measured was n = 5, and the average value was the tensile strength. Further, a standard deviation was calculated from the measured value, and the standard deviation was divided by an average value, thereby calculating a variation coefficient (CV value (%)) as an index of variation.

  The tensile elastic modulus was expressed as 41 GPa almost as the theoretical value, and the tensile strength was as high as 680 MPa, and the CV value was 4%, which was a very small variation. From these results, it was found that mechanical properties and quality that can be applied to structural materials and outer plate members were obtained.

(Example 3)
A fiber sheet similar to Example 1 and a nonwoven fabric of resin were used, and in impregnating the fiber sheet with the resin, a calender roll was passed only once to prepare a semi-impregnated prepreg (semi-preg) substrate. The cut is inserted into the prepreg base material in the same manner as in Example 2, and the cut prepreg base materials are fused and integrated with each other over the entire surface by a double belt press in the same manner as in Example 2. A laminated base material was obtained by impregnating a resin into a fiber sheet with the whole material. When the obtained laminated base material was left in a vacuum oven for 1 day and then the void ratio was measured, the volume content of voids was 2.0%. This laminated substrate was molded in the same manner as in Example 2 to obtain a flat fiber-reinforced plastic.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile modulus of elasticity was 40 GPa, which was expressed as theoretically, and the tensile strength was as high as 650 MPa, and the CV value was also as small as 6%.

Example 4
A laminated base material was prepared in the same manner as in Example 2 except that the cut prepreg base material was left in a room with a humidity of 60% or more for one day, and a plurality of layers were stacked and double belt pressed. When the obtained laminated base material was left in a vacuum oven for 1 day and then the void ratio was measured, the volume content of voids was 3.5%. It was speculated that the moisture absorbed absorbed the void formation. Thereafter, this laminated substrate was molded in the same manner as in Example 2 to obtain a flat fiber-reinforced plastic.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile modulus of elasticity was 40 GPa, which was almost the same as the theoretical value, but the tensile strength was 510 MPa, and its CV value was slightly higher at 11%.

(Example 5)
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 using a twin-screw extruder (TEX-30α2) manufactured by Nippon Steel Works Co., Ltd., pellets melted and kneaded at 200 ° C. into a 34 μm-thick resin film using a press heated at 200 ° C. processed. The resin film is sandwiched from both sides of the same fiber sheet as in Example 1, and the fiber sheet is impregnated by heating and pressing through a calender roll many times. The fiber deposition content Vf is 50%, the thickness is 0. A 14 mm prepreg substrate was prepared. When this prepreg base material was left in a vacuum oven for 1 day and then the void ratio was measured, the volume content of the void was 1.0%.

  The obtained prepreg base material was laminated and integrated as in Example 2 to obtain a laminated base material. When this laminated substrate was left in a vacuum oven for 1 day and the void ratio was measured, the volume content of voids was 1.1%. The obtained laminated substrate was molded in the same manner as in Example 2 to obtain a flat fiber reinforced plastic.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile elastic modulus was 38 GPa, the tensile strength was 470 MPa, and the CV value was 6%, showing a small variation.

(Example 6)
In the punching die of Example 2, the interval between the blade-like sewing blades in which the cut portion and the uncut portion are arranged at intervals of 1 mm is adjusted so that the fiber length L divided by the pair of cut portions is 10 mm. Thus, a cut prepreg base material was obtained. Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile elastic modulus was slightly low as 36 GPa, the tensile strength was 580 MPa, and the CV value was as small as 5%.

(Example 7)
In the punching die of Example 2, the interval between the blade-like sewing blades in which cut portions and uncut portions are arranged at intervals of 1 mm is adjusted so that the fiber length L divided by the pair of cut portions is 100 mm. Thus, a cut prepreg base material was obtained. Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had some undulations in the fibers, but the fibers were flowing evenly to the ends. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile modulus was 42 GPa, which was almost the theoretical value, and the tensile strength was as high as 690 MPa, and the CV value was 7%, which showed a small variation.

(Example 8)
In the punching die of Example 2, a blade-like sewing blade in which cut portions and uncut portions are arranged at intervals of 1 mm is arranged, and the punching die embedded at an angle of 2 ° is pressed against the wooden die, and FIG. A straight cut in the direction of 2 ° was intermittently inserted into the entire surface from the fibers as shown to obtain a cut prepreg base material. The fiber length L divided by the cutting is 30 mm. The projected length Ws projected in the vertical direction of the cut fiber is 35 μm (the actual cut length is 1 mm), and 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 divided. Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had some undulations in the fibers, but the fibers were flowing evenly to the ends. There is no warpage as a whole, 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 and smoothness are maintained. It was. Although the tensile elastic modulus was 39 GPa and the tensile strength was as high as 740 MPa, the CV value was slightly increased to 8%.

Example 9
In the punching die of Example 2, the blade-like sewing blades in which the cut portion and the uncut portion are arranged at intervals of 1 mm are arranged, and the punching die embedded at a 25 ° angle is pressed against FIG. A straight cut in the direction of 25 ° was intermittently inserted into the entire surface from the fibers as shown to obtain a cut prepreg base material. The fiber length L divided by the cutting is 30 mm. The projected length Ws projected in the vertical direction of the cut fiber is 0.42 mm (actual cut length is 1 mm), and the fiber length is less than L by the adjacent cut as shown in FIG. ) Was parted. Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had some undulations in the fibers, but the fibers were flowing evenly to the ends. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile modulus of elasticity was 42 GPa, which was almost the theoretical value, the tensile strength was 540 MPa, and the CV value was 4%, showing little variation.

(Examples 10 and 11)
A cylindrical metal is cut out, a plurality of blades are provided on the circumference to form a rotating roller, pressed against the same prepreg substrate as in Example 1, and a straight line in the direction of 10 ° from the fiber as shown in FIG. A continuous cut was intermittently inserted into the entire surface to obtain a cut prepreg substrate. The fiber length L divided by a plurality of pairs of blades is 30 mm. The projection length Ws projected in the vertical direction of the cut fiber is 0.017 mm in Example 10 (the actual cut length is 0.1 mm), and 0.03 mm in Example 11 (the actual cut length is 0.17 mm). In either case, the blade could not cut the fibers partly, and the fibers having a fiber length L of 30 mm or more remained slightly but 5% or less. Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

Although none of the obtained fiber reinforced plastics had fiber undulations, the fiber did not reach the end of part of the surface layer. There is no warpage as a whole, 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 and smoothness are maintained. It was. In Example 10, the tensile modulus was as high as 40 GPa and the tensile strength was as high as 700 MPa, but the CV value was slightly increased to 9%. On the other hand, in Example 11, the tensile elastic modulus was 39 GPa and the tensile strength was as high as 720 MPa, and the CV value was 7% (Examples 12 and 13).
Using an automatic cutting machine, a linear notch in the direction of 10 ° was intermittently inserted from the fiber as shown in FIG. 4e) to obtain an incised prepreg base material. The fiber length L divided by the cutting is 30 mm. The projected length Ws projected in the vertical direction of the cut fibers is 1.5 mm in Example 12 (actual cut length is 8.6 mm), and 10 mm in Example 13 (actual cut length is 57.75 mm). 6 mm).

The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There is no warpage as a whole, 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 and smoothness are maintained. It was. In Example 12, the tensile elastic modulus was 40 GPa, the tensile strength was 580 MPa, and the CV value was as small as 4%. On the other hand, in Example 13, the tensile modulus was 40 GPa, the tensile strength was 550 MPa, and the CV value was 7% (Example 14).
Into the prepreg base material similar to that in Example 1, a straight cut in a direction of 10 ° from the fiber as shown in FIG. 4a) was continuously inserted using an automatic cutter, and then the orientation direction of the carbon fiber ( 0 ° direction) and a cut prepreg base having a regular cut at equal intervals, each cut into a size of 300 × 300 mm in a direction shifted 45 degrees to the right from the carbon fiber orientation direction (45 ° direction). The material was obtained. Among them, the notch is not made at every 5 mm around 300 × 300 mm, and the incision that is not separated by continuous incision is put in the direction of 10 ° from the fiber, and from the vicinity of the end of the incised prepreg base material The other end was inserted, and a cut was made in a range of 290 × 290 mm. The fiber length L divided by the cutting is 30 mm. After laminating the cut prepreg base material cut into 16 layers pseudo-isotropic ([−45 / 0 / + 45/90] _2S ), pressurization and pressure reduction are repeated while heating with a double belt press, The cut prepreg base materials were fused and integrated on the entire surface of the interlayer, and the periphery was cut off by 25 mm to obtain a 250 × 250 mm laminated base material having cuts on the entire surface.

The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile modulus was 39 GPa, the tensile strength was 560 MPa, and the CV value was 3%.

(Comparative Example 1)
Using an automatic cutter, the same prepreg substrate as in Example 1 was aligned in the direction of carbon fiber (0 ° direction) and 45 ° to the right of the carbon fiber alignment direction (45 ° direction). It cut | judged to the rectangle of 150x150 mm. Otherwise, a flat laminated substrate was prepared in the same manner as in Example 1, and was molded using a C-shaped molding die similar to that in Example 1 to obtain a fiber-reinforced plastic.

  It was found that the obtained fiber reinforced plastic had an unfilled portion and a resin-rich portion formed at the upper part of the standing surface, and did not follow a complicated shape. When the cross section was observed, no fiber was present in the extending direction of the laminated base material on the standing surface, and the prepreg layer in a direction perpendicular to the extending direction of the laminated base material was present with a thick uneven thickness. The layer swell was also large.

(Comparative Example 2)
A cut prepreg base material was prepared in the same manner as in Example 1, and 16 layers were simply stacked in a pseudo isotropic manner ([45/0 / −45 / 90] _2S ), and laminated base materials that were not fixed to each other were oven-bonded. It was placed inside and heated, and when the surface temperature reached 200 ° C., it was removed from the oven. The heated laminated substrate was arranged so as to be quickly pushed into the female mold 20 having a 100 × 100 mm cavity. At that time, since the cut prepreg base materials are not fixed to each other, the lamination angle is shifted, and the outer shape of the laminated base material protrudes from 100 × 100 mm, so that the laminated base material is pushed into the female mold. It took time. When molding was performed in the same manner as in Example 1, it was estimated that it took too much time to arrange the laminated base material in the female mold, and it was cooled and solidified before filling the C mold. The unfilled part remained on the upper part of the standing surface of the obtained fiber reinforced plastic.

(Comparative Example 3)
Using an automatic cutter, the same prepreg substrate as in Example 1 was cut into a plurality of 30 × 10 mm rectangles (30 mm in the orientation direction of carbon fibers) to obtain chopped fiber bundles. The obtained chopped fiber bundle is randomly spread on the release film so that the basis weight is about 3100 g / m ^2, and the release film is further placed thereon, and then heated and pressed into a flat plate shape with a press. Then, the whole mold release film was removed to obtain a stampable sheet. The stampable sheet thus obtained was cut into a 150 × 150 mm rectangle. The stampable sheet was placed in an oven and heated in the same manner as in Example 1, and when the surface temperature reached 200 ° C., the stampable sheet was taken out from the oven. The heated stampable sheet was placed so as to be quickly pushed into a female mold having a 100 × 100 mm cavity. Both the male mold and the female mold are temperature-controlled at 70 ° C., the male mold is pressed against the laminated base material arranged in the female mold, and is cooled by holding for 1 minute under a pressure of 6 MPa by a press machine. Demolded.

  The obtained fiber reinforced plastic was filled to every corner of the mold and showed good fluidity. When the cross section was observed, the laminated structure was not formed, and flocculation of the chopped fiber bundle and undulation in the thickness direction of the chopped fiber bundle were observed in part. It was speculated that the aggregation and undulation of these chopped fiber bundles adversely affected the mechanical properties of the fiber reinforced plastic.

(Comparative Example 4)
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 thermoplastic resin polyvinyl formal ("Vinylec (registered trademark) K" manufactured by Chisso Corporation) was kneaded with a kneader to uniformly dissolve the polyvinyl formal, and then the 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, resin films are overlapped on both surfaces of the same fiber sheet as in Example 1, impregnated with resin by heating and pressurizing, carbon fiber weight per unit area 125 g / m ² , fiber volume content Vf 55% A prepreg base material having a thickness of 0.125 mm was produced.

  The prepreg base material thus obtained was inserted in the same manner as in Example 2 to obtain a cut prepreg base material. The obtained cut prepreg base material was cut into a size of 250 × 250 mm in the carbon fiber orientation direction (0 ° direction) and in a direction shifted 45 degrees to the right from the carbon fiber orientation direction (45 ° direction). 16 layers of pseudo-isotropic ([45/0 / -45 / 90] 2S) layers were stacked, pressed and integrated using an epoxy resin tack to create a layered substrate.

  Using the above-mentioned laminated base material, the same mold as in Example 2 was used and placed at the approximate center on a flat plate mold having a 300 × 300 mm cavity, and then heated at 6 MPa by a heating type press molding machine. Under pressure, it was cured under conditions of 150 ° C. × 30 minutes to obtain a plate-like fiber reinforced plastic of 300 × 300 mm.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile modulus of elasticity was 47 GPa, which was almost the same as the theoretical value, and the tensile strength was as high as 690 MPa, and the CV value was 4%. However, since a chemical reaction is involved at the time of molding, there is a problem that productivity is inferior to that of Example 1.

(Comparative Example 5)
A stampable sheet was prepared in the same manner as in Comparative Example 2, and cut into a 250 × 250 mm rectangle. This stampable sheet was left in a vacuum oven for 1 day in the same manner as in Example 2, and then cold press-molded in the same manner as in Example 2. First, a stampable sheet was placed in the oven and heated. When the surface temperature reached 200 ° C., the stampable sheet was taken out from the oven. Next, after placing it at the approximate center on a flat plate mold temperature controlled to 70 ° C. having a 300 × 300 mm cavity, it was held for 1 minute under pressure of 6 MPa by a press machine, cooled, and demolded. A 300 × 300 mm flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. However, warpage was generated as a whole, many sink marks were generated at the end of the chopped fiber bundle, and smoothness was slightly difficult. The tensile elastic modulus was 35 GPa and the tensile strength was 260 MPa, but the CV value of the tensile strength was particularly varied as 20%. Since the chopped fiber bundle is easy to agglomerate without taking a laminated structure, it was assumed that the mechanical properties are not stably expressed by breaking the weakest part.

(Comparative Example 6)
In the punching die of Example 2, the fiber length L divided by the pair of cut portions is 7.5 mm so that the interval between the blade-like sewing blades in which the cut portions and the uncut portions are arranged at intervals of 1 mm is 7.5 mm. A cut prepreg substrate was obtained by adjusting. Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had no fiber undulation, and the fibers were flowing evenly to the end. There is no warpage as a whole, 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 and smoothness are maintained. It was. The tensile modulus was as low as 34 GPa, the tensile strength was 480 MPa, and the CV value was 7%.

(Comparative Example 7)
In the punching die of Example 2, the interval between the blade-like sewing blades in which the cut portion and the uncut portion are arranged at intervals of 1 mm is adjusted so that the fiber length L divided by the pair of cut portions is 120 mm. Thus, a cut prepreg base material was obtained. Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had some undulations in the fiber, and although the fiber was filled up to the end, fiber disturbance at the end was large.

(Comparative Example 8)
In the punching die of Example 2, the blade-like sewing blades in which cut portions and uncut portions are arranged at intervals of 1 mm are arranged, and the punching die embedded at an angle of 1 ° is pressed against the fiber to make 1 ° from the fiber. A straight cut in the direction of was intermittently inserted on the entire surface to obtain a cut prepreg base material. The fiber length L divided by the cutting is 30 mm. The projected length Ws projected in the vertical direction of the cut fibers was 17 μm (the actual cut length was 1 mm). The blade could not cut some fibers, and 5% or more of fibers with a fiber length L of 30 mm or more remained. Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had some undulations in the fiber, and although the fiber was filled up to the end, fiber disturbance at the end was large. The tensile modulus was 40 GPa and the tensile strength was as high as 700 MPa, but the CV value was a little higher at 10%.

(Comparative Example 9)
In the punching die of Example 2, the blade-like sewing blades in which cut portions and uncut portions are arranged at intervals of 1 mm are arranged, and the punching die embedded at a 45 ° angle is pressed against FIG. A straight cut in the direction of 45 ° was intermittently inserted into the entire surface from the fibers as shown to obtain a cut prepreg base material. The fiber length L divided by the cutting is 30 mm. The projected length Ws projected in the vertical direction of the cut fiber was 0.71 mm (actual cut length was 1 mm). Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  The obtained fiber reinforced plastic had some undulations in the fibers, but the fibers were flowing evenly to the ends. Although there is no warp as a whole, in the cut portion of the outermost layer, there are many portions where the reinforcing fibers are not present and the reinforcing fibers of the adjacent layer are peeking out, and the smoothness is slightly impaired by sink marks. Although the tensile modulus was as high as 41 GPa, the tensile strength was as low as 450 MPa (CV value 5%).

(Comparative Example 10)
In the punching die of Example 2, the blade-like sewing blades in which cut portions and uncut portions are arranged at intervals of 1 mm are arranged, and the punching die embedded at a 90 ° angle is pressed against FIG. 3 a). A straight cut in the direction of 90 ° was intermittently inserted into the entire surface from the fibers as shown to obtain a cut prepreg base material. The fiber length L divided by the cutting is 30 mm. The projection length Ws projected in the vertical direction of the cut fibers was 1 mm (the actual cut length was also 1 mm). Otherwise in the same manner as in Example 2, a flat fiber-reinforced plastic was obtained.

  Although the obtained fiber reinforced plastic had some undulations in the fibers, the fibers were flowing evenly to the ends. Although there is no warpage as a whole, there is a wide area where the reinforcing fibers in the outermost layer have no reinforcing fibers and the reinforcing fibers in the adjacent layer are peeking out, and there are many, and the smoothness is slightly impaired due to sink marks. It was. Although the tensile modulus was as high as 40 GPa, the tensile strength was as low as 400 MPa (CV value 4%).

It is an enlarged plan view which shows an example of the cutting pattern of the prepreg layer of this invention. It is an enlarged plan view which shows an example of the cutting pattern of the prepreg layer of this invention. It is a top view which shows several examples of the cutting pattern of the prepreg layer for a comparison. It is a top view which shows several examples of the cutting pattern of the prepreg layer of this invention. It is the top view and sectional drawing which show an example of the laminated base material for a comparison, and a fiber reinforced plastic. It is the top view and sectional view which show an example of the lamination substrate of the present invention, and fiber reinforced plastics. It is the top view and sectional view which show an example of the lamination substrate of the present invention, and fiber reinforced plastics. It is a top projection figure which shows an example of the lamination | stacking method of the lamination base material of this invention. It is sectional drawing which shows an example of the manufacturing method of the fiber reinforced plastics of this invention. It is sectional drawing which shows an example of the resin impregnation property of the prepreg layer of this invention.

Explanation of symbols

1: Fiber orientation direction 2: Fiber vertical 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 layer thickness direction 4f: Diagonal in the thickness direction Incision 5: Angle Θ between incision and fiber direction
6: Fiber length L divided by a notch paired in the fiber direction
7: Pre-preg layer 8: Width cut into each other by notches 9: Projected length Ws obtained by projecting the notches in the vertical direction of the reinforcing fibers
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 portion 16: Resin rich portion 17: Layer waviness 18: Reinforcement fiber rotation 19: Male die 20: Female die 21: Thickness direction central portion 22: Heat unevenly distributed between prepreg layers Plastic resin

Claims (19)

A prepreg layer composed of a plurality of reinforced fibers oriented in one direction and a thermoplastic resin is a flat laminated substrate integrated in two or more directions, and the reinforced fibers are formed on the entire surface of the prepreg layer. The absolute value of the angle Θ is a straight cut within a range of 2 to 25 °, and substantially all the reinforcing fibers are cut by the cut, and the reinforcing fibers cut by the cut A laminated substrate having a fiber length L in the range of 10 to 100 mm. The laminated substrate according to claim 1, wherein the cut has a projection length Ws projected in the vertical direction of the reinforcing fiber within a range of 30 μm to 1.5 mm. The laminated substrate according to claim 1 or 2, wherein the prepreg layer is laminated in a pseudo isotropic manner. The laminated base material according to claim 1, wherein a thermoplastic resin is unevenly distributed between the layers of the laminated base material. The laminated base material according to claim 4, wherein a central portion in the thickness direction of the prepreg layer is composed of only reinforcing fibers. The laminated substrate according to any one of claims 1 to 4, wherein a void ratio of the laminated substrate is 2% or less. The laminated base material according to any one of claims 1 to 5, wherein the prepreg layers are integrated in a dotted manner. The composite laminated base material by which the nonwoven fabric which consists of a reinforced fiber is distribute | arranged to the at least one surface of the said laminated base material in any one of Claims 1-7. The fiber reinforced plastic obtained by shape | molding the laminated base material in any one of Claims 1-7, or the composite laminated base material of Claim 8 in the three-dimensional shape. A straight notch is provided on the entire surface of the prepreg base material composed of unidirectionally oriented reinforcing fibers and a thermoplastic resin so that the absolute value of the angle Θ between the reinforcing fibers is within the range of 2 to 25 °. All the reinforcing fibers are divided by the incision, the fiber length L of the reinforcing fibers divided by the incision is set within a range of 10 to 100 mm, and a cut prepreg base material is used. A method for producing a laminated base material, characterized in that when the laminated cut prepreg base material is laminated, pressurization and decompression are repeated until a predetermined void ratio is obtained. The manufacturing method of the laminated base material of Claim 10 using what the thermoplastic resin was unevenly distributed and impregnated only on the surface of the reinforced fiber oriented in one direction as said prepreg base material. The method for producing a laminated base material according to claim 10, wherein a prepreg base material having a void ratio of 1% or less is used. A fiber sheet is formed by aligning reinforcing fibers in one direction in a flat shape, a nonwoven fabric made of a thermoplastic resin is sandwiched from both sides of the fiber sheet, and the fiber sheet is impregnated with the fiber sheet to create the prepreg base material. The manufacturing method of the laminated base material in any one of Claims 10-12. The cutting prepreg base material is formed by cutting a predetermined outer shape at the same time as inserting a notch using a punching die for inserting the notch into the entire surface of the prepreg base material. The manufacturing method of the laminated base material of crab. In laminating a plurality of the cut prepreg base materials to form a laminated base material, the laminated base materials are laminated so as to include the cut prepreg base materials having different outer shapes, and a laminated base material having a portion having a different laminated thickness is formed. The manufacturing method of the laminated base material in any one of Claims 10-14. A fiber that heats and softens the laminated substrate according to any one of claims 1 to 7 or the composite laminated substrate according to claim 8, and then cold-presses to form a three-dimensional fiber reinforced plastic. A method of manufacturing reinforced plastics. The manufacturing method of the fiber reinforced plastics of Claim 16 which presses and shape | molds a shaping | molding die against the center part of the said laminated base material after holding the peripheral part of the said laminated base material. The manufacturing method of the fiber reinforced plastics of Claim 16 which arrange | positions the said laminated base material smaller than the cavity of this shaping | molding die in a shaping | molding die cavity, and shape | molds the said laminated base material, and shape | molds a fiber reinforced plastic. The method for producing a fiber-reinforced plastic according to any one of claims 16 to 18, wherein pressurization and decompression are repeated in the cold press.

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