Molded product with multiple holes

Abstract

To provide a molded product having excellent mechanical strength and having holes h for the purpose of reducing scrap material.SOLUTION: A molded product including discontinuous reinforcing fibers and resin has a plurality of holes h and a base part. The base part has a bridge part sandwiched between hole hi=k and hole hi=k+1, and the bridge part has a region where reinforcing fibers are continuously arranged so as to connect the hole hi=k and the hole hi=k+1. The base part has a peripheral edge part along the periphery of the hole h, and the peripheral edge part has a protrusion part that protrudes toward one surface side of the molded product.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a molded article having a plurality of holes and a method for producing the same. [Background technology]

[0002] When holes are made in a molded product, they are made using a punching machine or drill using a press. The shapes and sizes of the holes vary widely, and they are generally made at regular intervals.

[0003] Patent Document 1 provides a method and an apparatus for efficiently producing cut pieces even when the cutting blade has a closed-loop structure. It describes that the positional accuracy of the cutting blade can be maintained high even when cutting composite materials continuously, and that even when using a cutting blade with a closed-loop structure, the cut pieces can be smoothly discharged, making it possible to continuously cut composite materials and produce cut pieces.

[0004] Patent Document 2 describes a method for manufacturing a punched plate by drilling multiple holes in a single plate. It proposes punched holes that do not produce burrs on the surface behind the punched holes and that have the same gloss on the front and back sides.

[0005] Patent Document 3 provides a pressed product that can maintain a firm press-fit state of a shaft pressed into a boss portion. The process includes a primary boss forming step of forming a primary boss having a hole and a protrusion that protrudes from the periphery of the hole in a portion of a flat plate-shaped material that corresponds to the boss portion, and a boss portion forming step of forming the boss portion by pressing and deforming the protrusion in the protruding length direction.

[0006] In Patent Document 4, in a resin structure constructed by laminating multiple base materials made of resin containing reinforcing fibers, the fiber orientation angle around the fastening penetration portion is adjusted in order to suppress the occurrence of interlayer delamination. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2017 / 110596 [Patent Document 2] Japanese Patent Publication No. 2019-202363 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-7253 [Patent Document 4] Japanese Patent Application Publication No. 2020-203436 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the cutting device described in Patent Document 1 uses a Thomson blade to open holes by pushing the composite material apart. This makes it difficult to shorten the shortest distance between holes. If an attempt is made to shorten the shortest distance between holes and produce a molded product with multiple holes, cracks may occur on the inner surface of the holes, reducing the strength of the holes and even causing the composite material to break.

[0009] In the invention described in Patent Document 2, the punched plate contains continuous fibers. Therefore, when multiple holes are formed in the punched plate, the mechanical strength is extremely weakened depending on the tensile direction.

[0010] Patent Document 3 studies press-molding a rolled steel plate into a shape with a boss, but does not study any composite material containing reinforcing fibers and resin. Also, while protrusions are provided around the holes, these are for providing bosses, and the size of the holes is too small. No study has been conducted on larger holes using composite materials containing reinforcing fibers and resin.

[0011] In Patent Document 4, the study is conducted on the assumption that there is only one fastening-through portion. Furthermore, because the fiber length is too short, no study is conducted on the relationship between the fastening-through portion and the arrangement of the reinforcing fibers. [Means for solving the problem]

[0012] As a result of intensive studies by the present inventors, it has been found that the above problems can be solved by the means shown below, and the present invention has been achieved.

[0013] 1. A molded product containing discontinuous reinforcing fibers and a resin, The molded product includes a plurality of holes h and a base portion, The base portion has holes h and holes h i=k+1 and has a bridge portion sandwiched therebetween. In the bridge portion, there is a region where reinforcing fibers are continuously arranged so as to connect the holes h i=k and the holes h i=k+1 and the holes h, The base portion includes a peripheral portion along the periphery of the hole h, and the peripheral portion has a protrusion that protrudes on one surface side of the molded product. Molded product. 2. The molded product according to 1 above, satisfying 0.5×V2<V1≦V2. V1: The volume of the protrusion V2: The projected area Si of the hole h × the average thickness t1 of the base portion 3. The molded product according to any one of 1 to 2 above, where L1<r1. However, L1: The height L1 of the protrusion r1: The radius of the largest inscribed circle of the hole h That is. 4. The molded product according to any one of 1 to 3 above, where L2<L1. However, L1: The height of the protrusion L2: The length of the shortest width of the bridge width of the bridge portion 5. The molded product according to 4 above, where the length L2 of the shortest width of the bridge width of the bridge portion is 3.0 mm or more and 8. mm or less. That is. 6. The molded product according to any one of 1 to 5 above, where S1<S2. However, [[ID=​​​​​The sum of the projected areas Si [Number] is as follows. 7. The molded product is an integrally molded product, the protrusion forms a cylinder, Regarding the reinforcing fibers included in the protrusion, the circumferential tensile fracture stress F1 of the cylinder and the tensile fracture stress F2 in the height direction of the cylinder satisfy F1 > F2. The molded product according to any one of 1 to 6 above. 8. In the protrusion of the molded product, When observing a cross-section parallel to the base portion, the number of cross-sections of reinforcing fibers per unit area N1 and When observing a cross-section perpendicular to the base portion, the number of cross-sections of reinforcing fibers per unit area N2 satisfy N1 > N2. The molded product according to any one of 1 to 7 above. The molded product according to any one of 1 to 8 above, wherein the tensile fracture stress of the molded product exhibits isotropy. 10. The weight average fiber length Lw of the reinforcing fiber is 1 mm or more and 100 mm or less, The molded product includes reinforcing fibers longer than the shortest width of the bridge width of the bridge portion, The resin is a thermoplastic resin. The molded product according to any one of 1 to 9 above. 11. The molded product according to any one of 1 to 10 above, wherein the arrangement of the holes h is a honeycomb arrangement. The molded product according to any one of 1 to 11 above, wherein the reinforcing fibers are continuously arranged in all the bridge portions included in the molded product. <00​​​​​​​​15. A method for producing the molded product according to any one of 1 to 13 above by press-molding a flat composite material containing reinforcing fibers and a thermoplastic resin, wherein the composite material has a region hp where the hole h is to be formed and a region Bp where the bridge is to be formed, Step A-101: Heating the region hp, Step A-201: The composite material with the region hp heated is press-molded using a first mold and a second mold to deform it and form the hole h. A method for producing a molded article. 16. A method for producing a molded product according to 15 above, in which the formation regions hp are arranged in a plurality of rows, In the step A-101, the predetermined formation region hp of any one row is heated using an infrared heating device, and then press-molded in the step A-201, Returning to A-101 again, the next row of the formation planned region hp is press-molded using the infrared heating device, A method for continuously manufacturing molded products. 17. A method for producing the molded article according to 15 above, comprising the steps of: In the step A-101, the region Bp is not heated to a temperature higher than the softening temperature of the resin. A method for producing a molded article. 18. A method for producing a molded article according to any one of 14 and 15 above, comprising: After providing a plurality of precursor holes in the composite material, The composite material is press-molded using a first molding die and a second molding die, thereby pressing and deforming a precursor hole provided in the composite material to form the hole h. A method for producing a molded article. [Effects of the Invention]

[0014] The molded article of the present invention has holes h i=k and hole h i=k+1There is a region where the reinforcing fibers are continuously arranged so as to be connected thereto, and the base portion includes a peripheral portion along the periphery of the hole h, the peripheral portion has a protrusion, and the protrusion protrudes on one side of the molded product. Therefore, compared with a punching plate in which a hole is provided by simply punching the molded product with a drill or the like, the mechanical strength around the hole and the stability of the mechanical strength can be improved.

[0015] Furthermore, by setting the relationship between the volume V2 obtained by multiplying the projected area of the hole h by the thickness of the base portion and the volume of the protrusion to be 0.5×V2<V1≦V2, when producing a molded product using a composite material, the amount of waste material generated can be reduced.

Brief Description of Drawings

[0016] [Figure 1] Schematic diagram showing an example of the molded product of the present invention. [Figure 2] Schematic diagram showing sampling locations for measuring the degree of two-dimensional random dispersion. [Figure 3] Schematic diagram showing an example of the molded product of the present invention. [Figure 4] (a) Schematic diagram showing an example of the molded product of the present invention. (b) Cross-sectional view of the molded product of the present invention [Figure 5] (a) Schematic diagram showing a state where reinforcing fibers are continuously arranged so as to connect the hole hi=k and the hole hi=k+1. Also, a photograph of the reinforcing fibers existing in the bridge portion is illustrated. (b) Schematic diagram showing a state where the ends of the reinforcing fibers arranged so as to connect the hole hi=k and the hole hi=k+1 in the peripheral portion are oriented toward one side of the molded product. [Figure 6] Schematic diagram showing a state where the ends of the reinforcing fibers are stored in the protrusion and no cross-section of the fibers is observed on the peripheral wall surface C. [Figure 7] Cross-sectional view when punching treatment is performed using the prior art. [Figure 8] Photograph showing an example of a molded product with a hole made using the prior art. [Figure 9] Photograph showing an example of the molded product of the present invention. [Figure 10] Schematic diagram of the molded product of the present invention. [Figure 11] Results of tensile tests on Example 1 and Comparative Example 1. [Figure 12] (a) A schematic diagram showing the process for producing a molded product of the present invention, in which a heated composite material is placed on a lower mold. (b) The upper mold has begun to descend. (c) The drilling jig attached to the upper mold has begun to penetrate the composite material. (d) A schematic diagram showing the through-hole widening and the beginning of the formation of a protrusion. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these.

[0018] [Reinforced fiber] In this specification, the reinforcing fiber is preferably at least one selected from the group consisting of carbon fiber, aramid fiber, glass fiber, polyester fiber, nylon fiber, polypropylene fiber, and polyethylene fiber, and more preferably carbon fiber or glass fiber.

[0019] [Reinforced fiber: carbon fiber] 1. Carbon fiber in general When carbon fibers are used, polyacrylonitrile (PAN)-based carbon fibers, petroleum / coal pitch-based carbon fibers, rayon-based carbon fibers, cellulose-based carbon fibers, lignin-based carbon fibers, phenol-based carbon fibers, etc. are generally known, and any of these carbon fibers can be suitably used in the present invention. Among these, polyacrylonitrile (PAN)-based carbon fibers are preferred in the present invention because of their excellent tensile strength. As a PAN-based carbon fiber, for example, TENAX (registered trademark) STS40-24KS (average fiber diameter 7 μm) carbon fiber manufactured by Teijin Limited can be used.

[0020] 2. Carbon fiber sizing agent The carbon fiber used in the present invention may have a sizing agent attached to its surface. When using carbon fiber with a sizing agent attached, the type of sizing agent can be appropriately selected depending on the type of carbon fiber and the type of resin used in the X material or Y material, and is not particularly limited.

[0021] [Reinforced fiber: glass fiber] The case where the reinforcing fiber used in the present invention is glass fiber will be described. 1. Glass fiber in general The glass fiber used in the present invention may be any glass fiber generally referred to as glass fiber. The glass composition is not particularly limited, and may include A-glass, C-glass, E-glass, etc., and may contain components such as TiO2, SO3, and P2O5 in some cases. For example, Nitto Boseki's E-glass RS240QR-483 (count: 2400 g / 1000 m) glass fiber can be used as the glass fiber.

[0022] 2.Glass fiber sizing agent The glass fiber used in the present invention may have a sizing agent attached to its surface. When using glass fiber with a sizing agent attached, the type of sizing agent can be appropriately selected depending on the type of glass fiber and the type of resin, and is not particularly limited. Glass fiber that has been pre-treated with a conventionally known coupling agent such as an organosilane compound, an organotitanium compound, an organoborane compound, or an epoxy compound can be preferably used.

[0023] [Reinforced fiber: Base part configuration] In the base portion excluding the peripheral portion of the molded article of the present invention, the reinforcing fibers are preferably discontinuous fibers and dispersed in the in-plane direction. In order to disperse the reinforcing fibers in the in-plane direction in the base portion excluding the peripheral portion of the molded article, it is preferable that the reinforcing fibers contained in the composite material are dispersed in the in-plane direction.

[0024] "Reinforcing fibers are dispersed in the in-plane direction" means that the reinforcing fibers are evenly spread across the plane. In other words, the fibers are not concentrated in one direction, but are spread across the plane. This is expected to improve the strength and rigidity of the material evenly and to distribute stress and load more effectively.

[0025] More specifically, the reinforcing fibers being dispersed in the in-plane direction preferably means that the fiber axes of the reinforcing fibers form an angle of 45° or less with the in-plane direction.

[0026] 1. In-plane direction The in-plane direction is an arbitrary direction of a parallel plane perpendicular to the thickness direction of a composite material or molded product. The composite material is preferably a plate-shaped material. For example, the in-plane direction is the XY direction shown in Figures 1, 2, 3, 4(a), and 5(a) and 5(b).

[0027] 2. Random distribution in two dimensions It is preferable that the reinforcing fibers dispersed in the in-plane direction are dispersed randomly in two dimensions. In the region where the composite material is press-molded without flow, the shape of the reinforcing fibers is almost maintained before and after molding. Therefore, it is preferable that the reinforcing fibers contained in the non-flow region of the molded product formed from the composite material are also dispersed two-dimensionally randomly in the in-plane direction. In other words, it is preferable that the base portion excluding the peripheral portion of the molded product of the present invention remains in the state where the reinforcing fibers contained in the composite material were in almost the same state.

[0028] Here, "two-dimensionally randomly dispersed" refers to a state in which the reinforcing fibers are not oriented in a specific direction in the in-plane direction of the composite material or molded article, but are oriented randomly, and are arranged in the sheet plane without any specific directionality overall. A composite material (or molded article) obtained using discontinuous fibers dispersed in this two-dimensionally random manner is a substantially isotropic composite material (or molded article) that does not have anisotropy in the plane.

[0029] The degree of two-dimensional random orientation is evaluated by determining the ratio of the tensile breaking stresses in two mutually perpendicular directions. If the ratio (Eδ) obtained by dividing the larger of the tensile breaking stresses measured in any direction of the composite material (or molded article) by the smaller of the two measured tensile breaking stresses in the direction perpendicular to that direction is 5 or less, more preferably 2 or less, and even more preferably 1.5 or less, the reinforcing fibers can be evaluated as being two-dimensionally randomly dispersed.

[0030] 3. Tensile breaking stress of molded product In the present invention, the tensile stress at break of the molded article is preferably isotropic. The isotropy of the tensile stress at break is evaluated by determining the ratio of the tensile stress at break in two mutually perpendicular directions. The tensile stress at break of the molded article can be evaluated as isotropic if the (Eδ) ratio, calculated by dividing the larger of the tensile stresses measured in a given direction of the molded article and the direction perpendicular thereto by the smaller, is 5 or less, more preferably 2 or less, and even more preferably 1.5 or less.

[0031] Here, the direction showing isotropy is a plane perpendicular to the plate thickness direction, more specifically, the XY direction in FIGS.

[0032] In the molded product of the present invention, since the area of ​​the hole h is large, the samples for measuring the tensile breaking stress of the molded product can be taken, for example, as shown in 201 and 202 in Figure 2. This makes it possible to measure the tensile breaking stress in any direction of the molded product and in the direction perpendicular to that direction.

[0033] If the resin contained in the molded product is a thermoplastic resin and the molded product has a three-dimensional shape including curved surfaces, the isotropy of the tensile breaking stress can be evaluated by heating the molded product above its softening temperature, returning it to a flat plate shape, and then solidifying it. After that, test pieces can be cut out and the tensile breaking stress measured to confirm the degree of isotropy of the molded product.

[0034] [Reinforced fiber: Shape of protrusion] At the protrusions of the molded product, When observing a cross section parallel to the base part, the number of cross sections of reinforcing fibers per unit area N1, When observing a cross section perpendicular to the base portion, the number of cross sections of reinforcing fibers per unit area N2 is It is preferable that N1>N2 be satisfied. Observation of a cross section parallel to the base portion means observation from the Z direction in FIG. 1, for example. Observation of a cross section perpendicular to the base portion means observation from the XY plane direction in FIG. 1, for example. The cross section of the reinforcing fiber to be counted is only that where the major axis α and minor axis β of the reinforcing fiber cross section satisfy α / β≧1.5. If the cross-sectional area N1 and the cross-sectional area N2 satisfy N1>N2, the reinforcing fibers are oriented in the Z direction, which improves the mechanical strength of the hole h.

[0035] [Reinforced fiber: fiber length] The molded article of the present invention preferably contains discontinuous reinforcing fibers having a weight-average fiber length Lw of 1 mm or more and 100 mm or less. When discontinuous reinforcing fibers are used, formability is improved compared to fiber-reinforced plastics using only continuous fibers, making it easier to create complex molded articles. Furthermore, by using discontinuous reinforcing fibers, even if stress is applied to the molded article from any direction, it is unlikely that a direction will result in extremely weak mechanical properties.

[0036] The weight-average fiber length Lw of the reinforcing fibers is preferably 3 mm or more and 80 mm or less, and more preferably 5 mm or more and 60 mm or less. If the weight-average fiber length Lw of the reinforcing fibers is 100 mm or less, the flowability of the composite material is less likely to decrease when the composite material is produced by press molding, and it is easy to produce the composite material in the desired shape. Furthermore, if the weight-average fiber length Lw is 1 mm or more, the mechanical strength of the resulting fiber-reinforced resin member is less likely to decrease, which is preferable.

[0037] The weight average fiber length Lw and number average fiber length Ln of the reinforcing fibers can be calculated by the formulas (1) and (2) described below. In molded articles produced by injection molding, the weight-average fiber length of the reinforcing fibers is about 0.1 to 0.3 mm. Therefore, when the weight-average fiber length of the reinforcing fibers is set to 1 mm or more and 100 mm or less, it is preferable to produce the molded article by press molding.

[0038] In the present invention, discontinuous reinforcing fibers having different fiber lengths may be used in combination. In other words, the discontinuous reinforcing fibers used in the present invention may have a single peak in the weight-average fiber length distribution, or may have multiple peaks.

[0039] [Reinforcing fiber: number average fiber length Ln and weight average fiber length Lw] Generally, if the fiber length of each reinforcing fiber is Li, the number average fiber length Ln and weight average fiber length Lw can be calculated by the following formulas (1) and (2). The units of the number average fiber length Ln and weight average fiber length Lw are mm. Ln=ΣLi / I equation (1) Lw=(ΣLi 2 ) / (ΣLi)...Equation (2) Here, "I" indicates the number of reinforcing fibers measured.

[0040] When the fiber length is constant, the number-average fiber length and the weight-average fiber length are the same value. Reinforcing fibers can be extracted from molded products, for example, by heating them at 500°C for about 1 hour and removing the resin in a furnace.

[0041] The average fiber length can be calculated, for example, by measuring the fiber lengths of 100 fibers randomly extracted from a molded article to the nearest 1 mm using a vernier caliper or the like, and then calculating the average fiber length based on formula (1).

[0042] If the dispersion contains short fibers that cannot be measured with a caliper, remove the resin, then place the resulting reinforcing fibers in water containing a surfactant and thoroughly stir using ultrasonic vibrations. Samples for evaluation can be obtained by randomly sampling the stirred dispersion with a measuring spoon, and measuring the lengths of 3,000 fibers using a Nireco Luzex AP image analyzer. The measured fiber lengths can be used to calculate the number-average fiber length Ln and weight-average fiber length Lw using the same formulas (1) and (2) described above.

[0043] [Reinforced fiber: fiber volume ratio] Although there are no particular limitations on the fiber volume fraction Vf of the reinforcing fibers contained in the molded article, it is preferably 20 to 70%, more preferably 25 to 60%, and even more preferably 30 to 55%. The fiber volume fraction (Vf, unit: volume %) is the ratio of the volume of the reinforcing fibers to the total volume including not only the reinforcing fibers and resin but also other additives.

[0044] Although there is no limitation on the analysis of the reinforcing fiber volume fraction, it is recommended to measure it as follows. A sample is cut out from the molded product, and the resin is burned off in a furnace at 500°C for 1 hour. The mass of the sample is weighed before and after treatment to calculate the mass of the reinforcing fiber, resin, and other additives. Next, the volume ratio of the reinforcing fiber to the resin is calculated using the specific gravity of each component. Vf = 100 x reinforcing fiber volume / (reinforcing fiber volume + resin volume + other additive volume)

[0045] [resin] The resin contained in the molded article may be either thermosetting or thermoplastic. 1.Thermoplastic resin When the resin used is a thermoplastic resin, the type is not particularly limited, and a resin having a desired softening point or melting point can be appropriately selected and used. As the thermoplastic resin, one having a softening point in the range of 180°C to 350°C is usually used, but is not limited thereto.

[0046] Examples of thermoplastic resins include polyolefin resins, polystyrene resins, polyamide resins, polyester resins, polyacetal resins (polyoxymethylene resins), polycarbonate resins, (meth)acrylic resins, polyarylate resins, polyphenylene ether resins, polyimide resins, polyethernitrile resins, phenoxy resins, polyphenylene sulfide resins, polysulfone resins, polyketone resins, polyether ketone resins, thermoplastic urethane resins, fluorine-based resins, and thermoplastic polybenzimidazole resins.

[0047] The molded article of the present invention may use one type of thermoplastic resin or two or more types of thermoplastic resins. Examples of the use of two or more types of thermoplastic resins in combination include, but are not limited to, the use of thermoplastic resins having different softening points or melting points or the use of thermoplastic resins having different average molecular weights.

[0048] When a thermoplastic resin is used, it is more preferable to use a polyolefin resin, and even more preferable to use a polypropylene resin.

[0049] 2.Thermosetting resin The resin may be a thermosetting resin. When a thermosetting resin is used, it is preferably an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, or a phenol resin. One type of resin may be used alone, or two or more types may be used in combination.

[0050] Furthermore, when a thermosetting resin is used as the resin of the present invention, it is preferable to use a sheet molding compound (sometimes called SMC) containing reinforcing fibers. Because of its high moldability, sheet molding compounds can be easily molded into even complex shapes. Sheet molding compounds have higher fluidity and formability than continuous fibers, making it easy to create ribs and bosses.

[0051] [Other agents] The resin may contain additives such as various fibrous or non-fibrous fillers such as organic or inorganic fibers, flame retardants, UV-resistant agents, stabilizers, release agents, pigments, softeners, plasticizers, surfactants, etc. When a thermosetting resin is used, it may also contain thickeners, curing agents, polymerization initiators, polymerization inhibitors, etc. One type of additive may be used alone, or two or more types may be used in combination.

[0052] [Molded product: base part] The molded product of the present invention has a base portion (102). The base portion plays a role in supporting the hole h, providing stability and strength to the molded product. The base portion exemplified by 102 in FIG. 1 forms a flat plate in the molded product, but does not necessarily have to have a flat plate shape and may have ribs or bosses. Note that even if the hole h is a non-through hole, the base portion does not necessarily include the hole h. If the hole h is a through hole, the base portion naturally does not include the hole h.

[0053] [Molded product: periphery] The base portion has a peripheral portion that follows the periphery of the hole h. The peripheral portion refers to the region around the hole h, as exemplified by 103 in Fig. 1 and 502 in Fig. 5(b).

[0054] The peripheral region is preferably defined as the range extending from the boundary between the hole h and the base portion toward the base portion, and less than the average thickness t1 of the base portion.

[0055] The peripheral region is more preferably defined as a range extending from the boundary between the hole h and the base portion toward the base portion, the range being less than the average thickness t1×0.8 of the base portion.

[0056] It is more preferable to define the peripheral region as a range extending from the boundary between the hole h and the base portion toward the base portion, the range being less than 0.6 times the average thickness t1 of the base portion.

[0057] It is even more preferable to define the peripheral region as a range extending from the boundary between the hole h and the base portion toward the base portion, the range being less than 0.5 times the average thickness t1 of the base portion.

[0058] In terms of specific length, the peripheral region is preferably defined as a range of less than 3.0 mm from the boundary between the hole h and the base portion toward the base portion.

[0059] The peripheral region is more preferably defined as a range of less than 2.5 mm from the boundary between the hole h and the base portion toward the base portion.

[0060] It is more preferable to define the peripheral region as a range of less than 2.0 mm from the boundary between the hole h and the base portion toward the base portion.

[0061] It is even more preferable to define the peripheral region as a range of less than 1.5 mm from the boundary between the hole h and the base portion toward the base portion.

[0062] It is particularly preferable to define the peripheral region as a range of less than 1.0 mm from the boundary between the hole h and the base portion toward the base portion.

[0063] The peripheral region is most preferably defined as a range of less than 0.5 mm from the boundary between the hole h and the base portion toward the base portion.

[0064] For example, when the hole h is circular, the length indicated by 107 in FIG. 1 can be depicted as the length defined above.

[0065] [Molded product: Protrusion] The peripheral edge has a protrusion that protrudes from one side of the molded article. The protrusion may be provided over the entire peripheral edge area, or only in a partial area of ​​the peripheral edge. It is also preferable that the protrusion is provided so as to surround the hole h.

[0066] 1. One side Here, "one side" refers to a specific surface of the molded product, such as the protrusion 401 in Figure 4(a). In Figure 4(a), the one side is the upper side of the paper, which is the negative axis of the Z-axis depicted in Figure 4(a). The presence of the protrusion improves the strength of hole h.

[0067] By forming the protrusions, it becomes easier to bend the reinforcing fibers in a stapler shape, making it difficult for the fibers to become shorter, and maintaining the strength of the composite material. The presence of the protrusions increases the cross-sectional area of the molded product, and has the effect of improving the load-bearing stress of the bridge portion.

[0068] 2. Height L1 in the plate thickness direction (thickness in the Z-axis direction in Fig. 4(b)) It is preferable that the molded product satisfies L2 < L1. Here, L1: Height of the protrusion L2: Length of the shortest width of the bridge width of the bridge portion That is.

[0069] Fig. 1 illustrates the length L2 of the shortest width of the bridge width of the bridge portion, and Fig. 4(b) illustrates the height L1 of the protrusion. If L2 < L1, when inserting the battery into the hole, the battery can be easily positioned and fixed. Furthermore, by shortening the length of L2, the battery loading amount on the molded product can be increased. Due to the presence of the protrusions, the cross-sectional area of the bridge portion increases partially, and the load-bearing stress of the bridge portion is improved. More preferably, L2×2 < L1, still more preferably L2×3 < L1, even more preferably L2×4 < L1.

[0070] 3. Volume of the protrusion and the hole h region It is preferable that the molded product satisfies 0.5×V2 < V1 ≤ V2. More preferably, 0.7×V2 < V1 ≤ V2, still more preferably 0.8×V2 < V1 ≤ V2, even more preferably 0.9×V2 < V1 ≤ V2, and even more preferably 0.95×V2 < V1 ≤ V's. However, V1: Volume of the protrusion V2: Projected area Si of the hole h × average thickness t1 of the base portion That is.

[0071] V1 is the volume of the protrusion shown in FIG. 10. The volume of the protrusion is the volume of the protruding region shown in FIG. 4(b), and does not include the volume of the region with thickness t1. On the other hand, V2 represented by the above formula can also be rephrased as the volume of the planned hole formation region hp of the hole h in the composite material before the hole h1 is provided.

[0072] When the hole h is provided, the ratio (%) of the region where end materials may occur is represented by the sum of the projected area S1 of the base portion and S2 which is the sum of the projected area Si of the hole h shown by the formula (A). i=k Ratio (%) of the region where end materials may occur = S2 / (S1 + S2) × 100

[0073] If the protrusion is not formed by the planned hole formation region hp and the composite material is simply punched to provide the hole h, the entire planned hole formation region hp of the hole h (the region corresponding to the area S2 of the hole h) will become end materials, resulting in a large amount of waste.

[0074] On the other hand, the present invention provides a protrusion, which is integrally connected to the base portion. As a result, since the protrusion is formed using at least a part of the composite material in the planned hole formation region hp, the generation amount of end materials can be significantly suppressed, and the protrusion improves the mechanical properties of the molded product, and when used as a battery holder, the holding force of the battery is improved. More specifically, when 0.5 × V2 = V1, the generation amount of end materials is halved compared to the case where the composite material is simply punched to provide the hole h. When 0.95 × V2 = V1, the generation amount of end materials is 5% compared to the case where the composite material is simply punched to provide the hole h. In other words, the closer the value of V2 is to the value of V1, the less end materials are generated.

[0075] 4. Height of the protrusion 4.1 The height L1 of the protrusion and the radius r1 of the maximum inscribed circle of the hole h In the molded product of the present invention, it is preferable that L1 < r1. However, L1: The height L1 of the protrusion r1: The radius of the maximum inscribed circle of the hole h It is as follows.

[0076] The radius r1 of the maximum inscribed circle of the hole h represented by the above formula can also be rephrased as the radius r1 of the maximum inscribed circle of the planned formation region hp of the hole h in the composite material before the step of providing the hole h1.

[0077] By satisfying L1 < r1, a protrusion can be formed using at least a part of the composite material in the planned formation region hp of the hole. Therefore, the generation amount of end materials can be significantly suppressed, and the protrusion improves the mechanical properties of the molded product, and when used as a battery holder, the holding force of the battery is improved.

[0078] 4.2 The height L1 of the protrusion and the average thickness t1 of the base portion The average thickness t1 of the base portion and the height L1 of the protrusion preferably satisfy t1×0.05 ≤ L1. Figures 4(a) and (b) illustrate the average thickness t1 of the base portion and the height L1 of the protrusion. If t1×0.05 ≤ L1, the cross-sectional area of the bridge portion increases partially, and the load-bearing stress of the bridge portion is improved. More preferably, t1×0.1 ≤ L1 ≤ t1×20, and still more preferably, t1 ≤ L1 ≤ t1×15. More specifically, the total value L1 + t1 of the average thickness t1 of the base portion and the height L1 of the protrusion is preferably 1.0 mm or more and 50.0 mm or less, more preferably 1.5 mm or more and 40 mm or less, still more preferably 1.0 mm or more and 30 mm or less, and even more preferably 1.5 mm or more and 25 mm or less. Also, when there are a plurality of protrusions, it is preferable that at least one protrusion is within the above range, and it is more preferable that all the protrusions are within the above range.

[0079] 5. Thickness of the wall of the protrusion (thickness in the X-axis direction in Fig. 4(b)) When the protrusion is provided so as to surround the hole h, it can be said that the cylindrical molded body is disposed on one surface side of the molded product. In this case, the thickness W of the wall of the cylindrical protrusion is preferably 0.5 mm ≦ W < t1 with respect to the average thickness t1 of the base portion, more preferably 0.75 mm ≦ W < t1 × 0.8, still more preferably 1.0 mm ≦ W ≦ t1 × 0.6, and even more preferably 1.0 × t1 ≦ W ≦ 0.5 × t1. The thickness W of the wall of the protrusion can be exemplified by (r2 - r1) / 2 in FIG. 4(b). When the protrusion has a cylindrical shape, r2 is the outer diameter of the protrusion and r1 is the inner diameter of the protrusion. Further, the thickness W of the wall of the protrusion is preferably uniform (equal thickness).

[0080] 6. Shape of the protrusion The shape of the protrusion is not particularly limited, and it may be cylindrical, and more preferably a cylindrical tube. The protrusion is preferably thinner toward the tip. Also, one surface side (hole h) of the tube may be penetrated or non-penetrated.

[0081] [Molded product: Hole h] The molded product of the present invention includes discontinuous reinforcing fibers and a resin, and has a plurality of holes h. 1. Hole h The molded product of the present invention has a plurality of holes h. FIG. 1 is an example of the molded product of the present invention, and a plurality of holes h (for example, 101 in FIG. 1) are provided in the molded product.

[0082] Also, starting from the hole h at the end of the molded product and counting in order of adjacent i = 1, 2, 3 ··· k ··· n, any hole is represented as hole h i=k That is, hole h i=k and hole h i=k+1 are adjacent. In FIG. 1, hole h i=1 hole h i=2 hole h i=3 are illustrated.

[0083] Hole h i=k and hole h k+1 The shortest distance between and is preferably 3.0 mm or more and 8.0 mm or less, and more preferably 4.0 mm or more and 7.0 mm or less. Hole h i=k and hole hi=k+1 The shortest distance between the bridge and the bridge section can also be expressed as the shortest width L2 of the bridge section, and is exemplified by L2 in Figure 1.

[0084] 2. Hole placement While there are no particular limitations on the arrangement of the multiple holes h, it is more preferable for the holes h to be circular and for each hole h to be surrounded by six holes h. A honeycomb arrangement is more preferable. In this case, the arrangement would be as shown in Figures 1 and 3. The honeycomb arrangement maximizes space utilization. (1) Because each hole h shares a base with adjacent holes h through bridges, more holes h can be arranged in the same area compared to other shapes. (2) The honeycomb arrangement also provides even force distribution and strength. This shape has many connection points between holes h, providing structural stability. (3) Furthermore, the honeycomb arrangement maximizes material utilization efficiency by creating the maximum amount of space with the minimum amount of material. (4) Finally, the honeycomb arrangement promotes air circulation, providing a cooling effect. Air passing through the holes h evenly distributes heat, helping to regulate the temperature of the holes h.

[0085] 3. Bridge section The molded article of the present invention has a plurality of holes h and a base portion, and the base portion has the holes h i=k and hole h i=k+1 The bridge portion is, for example, the black area 105 in FIG. 1, and the hole h i=k and hole h i=k+1 The bridge portion 105 in FIG. 1 is an example, and the other holes h in FIG. i=k and hole h i=k+1 The bridge portion also exists in the area sandwiched between the

[0086] 4. Hole area In the present invention, it is preferable that S2>S1 be satisfied. S1: Projected area of ​​the base S2: Sum of the projected areas Si of the holes h shown in the following formula (A)

number

[0087] For example, in FIG. 1, S1 is the area of ​​the base portion 102, and S2 is the area of ​​the hole h(h i=1 , h i=2 , h i=3 , ···). When S2>S1, the area of ​​the base portion becomes relatively small, and as a result, the area of ​​the bridge portion also becomes small.

[0088] 5. Through holes and non-through holes The holes h in the present invention may be through holes or blind holes. Preferably, the holes h are through holes. When used as a battery holder, the molded article of the present invention can penetrate all the way to the inside of the battery.

[0089] Even if the hole h does not penetrate through, the projected area Si still indicates the area of ​​the hole h. The projected area of ​​the hole h is measured by observing the surface opposite to the surface on which the protrusion protrudes.

[0090] 6. Shape of hole h When the molded product is observed so that the holes and bridges are visible (when observed from the Z-axis direction in FIG. 1), the shape of the holes h is not particularly limited, and may be a circle, an ellipse, a triangle, a square, a rectangle, or any other quadrilateral, or any of various polygonal shapes. A circle is preferred.

[0091] [Molded part: Bridge section and reinforced fiber] 1. In the present invention, it is preferable that the molded product contains reinforcing fibers longer than the shortest bridge width of the bridge portion. The bridge width of the bridge portion is shown, for example, as L2 in Fig. 1. L2 in Fig. 1 shows an example of the length of the shortest bridge width of the bridge portion. The shortest bridge width of the bridge portion is the length of the hole h i=k and hole h i=k+1 The shortest distance between the bridge and the hole h is the shortest distance between the bridge and the hole h. The molded product contains reinforcing fibers that are longer than the shortest width of the bridge portion, so that the bridge portion can be reliably reinforced with fibers. i=k and hole h i=k+1 In other words, the hole hi=k and hole h i=k+1 It can be said that the reinforcing fibers are arranged continuously to bridge the gap between the holes. i=k and hole h i=k+1 The state in which the reinforcing fibers are continuously arranged so as to connect the above is shown in 501 of Figure 5(a). Also, a photograph of the continuously arranged reinforcing fibers is shown as an enlarged portion of the bridge portion of Figure 5(a).

[0092] When there are multiple bridge portions, it is sufficient that the reinforcing fibers are continuously arranged in at least one bridge portion, and it is preferable that the reinforcing fibers are continuously arranged in all bridge portions included in the molded product.

[0093] 2. In the molded article of the present invention, the area fraction Cf of the reinforcing fibers exposed on the inner wall surface C of the hole h when observing the cross section is preferably smaller than the fiber volume fraction Vf contained in the entire molded article. An example of the inner wall surface C is shown in Figure 5(a).

[0094] In conventional methods (e.g., the methods described in Patent Document 2 and JP-A-2019-202363), when punching is used to create holes in a composite material, fiber cross sections are observed on the inner wall surface of the hole, and the area ratio of these cross sections corresponds to the fiber volume ratio. When conventional punching is performed on a composite material with dispersed discontinuous reinforcing fibers, the fiber length around the hole becomes shorter, resulting in a decrease in strength around the hole.

[0095] On the other hand, the area ratio Cf value when observing the cross section of the reinforcing fiber exposed on the inner wall surface C of the hole h of the present invention is preferably smaller than the fiber volume ratio Vf value contained in the entire molded article. This means that the fiber cross section observed on the inner wall surface C is smaller than when observing holes made by conventional punching processes. This is because the fibers are not cut along the way, and the fiber ends are bent and run along the inner wall surface. As a result, the area ratio Cf value when observing the cross section of the reinforcing fiber exposed on the inner wall surface C of the hole h can be made smaller than the fiber volume ratio Vf value contained in the entire molded article. When making holes, bending the fibers without cutting them as much as possible can improve the strength around the holes.

[0096] Although there is no particular limitation on the area fraction Cf, it is preferably 10% or more and less than 60%, more preferably 15% or more and less than 50%, and even more preferably 20% or more and less than 45%. The area fraction Cf (unit: area%) is the ratio of the area of ​​the reinforcing fibers to the total area including not only the reinforcing fibers and resin but also other additives, and is expressed by the following formula: Although there is no limitation on the analysis of the reinforcing fiber volume fraction, it is recommended to measure it as follows. Cf = 100 x reinforcing fiber volume / (reinforcing fiber area + resin area + area of ​​other additives)

[0097] 3. Orientation of the ends of reinforcing fibers The base portion has a peripheral portion along the periphery of the hole h, and the peripheral portion has a hole h i=k and hole h i=k+1 Preferably, the ends of the reinforcing fibers arranged to connect the above-mentioned fibers include those oriented toward one surface side of the molded article.

[0098] Here, "one side" refers to a specific surface of the molded article. In other words, in the base portion excluding the peripheral portion, the reinforcing fibers are randomly dispersed in the in-plane direction, but the ends of the reinforcing fibers present in the peripheral portion are preferably oriented toward one surface of the molded article. In other words, it is more preferable that the ends of the reinforcing fibers randomly dispersed in the in-plane direction are bent and oriented toward one surface of the molded article.

[0099] For example, 502 in Figure 5(b) is the peripheral portion, and in the peripheral portion depicted in Figure 5(b), the ends of the reinforcing fibers are depicted as being oriented on one side (503 in Figure 5(b)). Here, there is a central fiber portion where the reinforcing fibers are arranged to connect holes hi=k and hi=k+1, and end portions of the reinforcing fibers are oriented on one side. This shape is similar to that of a staple core, with two fiber ends paired at the tip of the fiber and formed by bending from the central fiber portion.

[0100] In FIGS. 5(a) and 5(b), the one surface side is the lower side of the paper, which is the negative axis direction of the Z axis direction depicted in FIGS. 5(a) and 5(b).

[0101] 4. At the periphery, holes h i=k and hole h i=k+1 The ends of the reinforcing fibers arranged to connect the above are oriented toward one side of the molded article, which can provide the following effects. (i) The fiber length of the reinforcing fibers can be maintained long. This is because the fibers at the periphery are bent to one side, so even if holes h are provided, the fibers are not cut midway and the fiber length is maintained. In this case, if a protrusion is provided at the periphery, long fibers can be stored sufficiently.

[0102] (ii) If no fiber cross section is observed on the inner wall surface C, it means that there is no interface between the resin and the fiber on the inner wall surface C. This makes it difficult for cracks to occur starting from the interface, improving the strength of the hole h.

[0103] (iii) Since the fiber cross section is not visible on the inner wall surface C, it is less likely that a person will get injured if they touch it. In other words, it is preferable that the outermost layer of the inner wall surface C is covered with resin. This resin layer is extremely thin, but even if you touch the hole, you will not come into direct contact with the fibers. In order to cover the outermost layer of the inner wall surface C with resin in this way, it is preferable to form the inner wall surface C by a molding process (rather than cutting with a drill). Note that if the inner wall surface C is formed by the molding process, no burrs will form on the inner wall surface C, but if protrusions are provided, burrs will form on the tips of the protrusions.

[0104] [Molded product: Orientation and protrusion of reinforcing fiber ends on one side] The base portion has a peripheral portion along the periphery of the hole h, and the peripheral portion has a hole h i=k and the hole h i=k+1 The ends of the reinforcing fibers arranged to connect the above are preferably oriented toward one surface of the molded article, and the peripheral edge has a protrusion that protrudes toward the one surface of the molded article. In other words, it is preferable that the bending orientation direction of the ends of the reinforcing fibers and the protrusion direction are oriented in the same direction.

[0105] Furthermore, it is preferable that the ends of the reinforcing fibers are stored in the protrusions. This stabilizes the strength around the hole. For example, Figure 6 shows the state in which the ends of the reinforcing fibers are stored in the protrusions, and the cross section of the fibers is not observed on the peripheral wall surface C.

[0106] [Integrated molding] The molded product of the present invention is preferably an integrally molded product containing reinforcing fibers and resin. Integral molding means that these are molded continuously without any seams and are not molded by joining separate components together. Such integral molding creates a structure in a single molding operation, and can be preferably achieved by press molding. Because it is created by integral molding, separate parts can be processed as a single part, making it possible to reduce the unit price of the part. In addition, the number of assembly steps is reduced, and the reduction in the number of parts also makes it possible to reduce inventory costs.

[0107] That is, it is preferable that the peripheral portion having the protrusions in the present invention and the base portion are formed integrally, and it is preferable that the reinforcing fibers are arranged across the entire surface from the base portion to the protrusions.

[0108] [Method of manufacturing molded products: Press molding] 1. Hot press molding and cold press molding When producing the molded article of the present invention, the composite material can be produced by press molding (sometimes called compression molding), and as press molding, molding methods such as hot press molding and cold press molding can be used. By press molding the composite material, it is possible to give the molded article various shapes.

[0109] 2.Cold press molding 2.1 Overview When a thermoplastic resin is used as the resin, press molding using cold press is preferred. In cold press molding, for example, a composite material heated to a first predetermined temperature is placed in a mold set to a second predetermined temperature, and then pressurized and cooled.

[0110] Specifically, if the thermoplastic resin contained in the composite material is crystalline, the first predetermined temperature is equal to or higher than the melting point, and the second predetermined temperature is lower than the melting point. If the thermoplastic resin is amorphous, the first predetermined temperature is equal to or higher than the glass transition temperature, and the second predetermined temperature is lower than the glass transition temperature. That is, the cold pressing method includes at least the following steps A-1) to A-2).

[0111] Step A-1) A step of heating the thermoplastic resin to a temperature above the melting point but below the decomposition temperature if the thermoplastic resin is crystalline, or above the glass transition temperature but below the decomposition temperature if the thermoplastic resin is amorphous.

[0112] Step A-2) The composite material heated in step A-1) is placed in a mold whose temperature is adjusted to below the melting point if the thermoplastic resin is crystalline, or below the glass transition temperature if the thermoplastic resin is amorphous, and then pressurized. By performing these steps, the molding of the composite material can be completed (a press-molded product can be produced).

[0113] The above steps must be performed in the order described above, but other steps may be included between each step, such as a shaping step, which is performed before step A-2), in which a shaping mold different from the mold used in step A-2) is used to pre-shape the mixture into the shape of the cavity of the mold.

[0114] The shape of the composite material may be a shape developed by computer through inverse molding analysis from the three-dimensional shape of the press-molded product to be manufactured.

[0115] 2.2 Heating of the region hp where hole h is to be formed When a flat composite material containing reinforcing fibers and a thermoplastic resin is produced by press molding, the composite material has a region hp where a hole h is to be formed and a region Bp where a bridge is to be formed, Step A-101: Heating the region hp, Step A-201: The composite material with the region hp heated is press-molded using a first molding die and a second molding die to deform the composite material and form the hole h; It is preferred to produce a molded article.

[0116] 2.2.1 Method of heating holes row by row In this case, the formation regions hp are arranged in multiple rows, and in step A-101, any one row of the formation regions hp is heated using an infrared heating device. After press-molding in step A-201, the process returns to step A-101 and the next row of formation regions hp is press-molded using the infrared heating device, thereby continuously producing molded products. This makes it possible to suppress disordering of the reinforcing fibers contained in the base portion. In other words, the orientation of the reinforcing fibers in the base portion can be kept constant before and after molding.

[0117] 2.2.2 Partial heating Furthermore, in the method for manufacturing a molded article of the present invention, it is preferable to selectively heat the region hp where the composite material is to be formed. Specifically, in step A-201, it is more preferable not to heat the region Bp above the softening temperature of the resin. This allows the protrusions to be formed without changing the fiber orientation of the bridge portion. Furthermore, with the molded article and manufacturing method of the present invention, even in a molded article in which the sum of the projected areas of the holes is large relative to the projected area of ​​the base portion, it is possible to eliminate or minimize the amount of waste material.

[0118] By not heating the region Bp above its softening temperature and leaving it in a solidified state, the planned formation region hp can be selectively molded, thereby suppressing the disordering of the reinforcing fibers contained in the base portion. In other words, the orientation of the reinforcing fibers in the base portion can be kept constant before and after molding. In step A-201, by using a composite material that exhibits isotropic tensile fracture stress and taking measures to prevent the region Bp from being heated above the softening temperature of the resin, it is possible to easily manufacture a molded product that exhibits isotropic tensile fracture stress. If the planned bridge formation region Bp is masked during partial heating, the molding pressure can be reduced, thereby reducing capital investment.

[0119] 3.Hot press molding In the hot press molding method, for example, a composite material is placed in a mold, pressure is applied while the temperature of the mold is increased to a first predetermined temperature, and the mold is cooled to a second predetermined temperature.

[0120] Specifically, when the thermoplastic resin constituting the composite material is crystalline, the first predetermined temperature is equal to or higher than the melting point, and the second predetermined temperature is lower than the melting point. When the thermoplastic resin contained in the composite material is amorphous, the first predetermined temperature is equal to or higher than the glass transition temperature, and the second predetermined temperature is lower than the glass transition temperature. The hot press molding preferably includes at least the following steps B-1) to B-4). B-1) A step of placing the composite material in a mold (second mold, lower mold). B-2) A process of applying pressure while heating the mold to a temperature above the melting point and below the thermal decomposition temperature of the thermoplastic resin if the thermoplastic resin is crystalline, or to a temperature above the glass transition temperature and below the thermal decomposition temperature of the thermoplastic resin if the thermoplastic resin is amorphous (first pressing process). B-3) A process of applying pressure in one or more stages, with the pressure in the final stage being 1.2 to 100 times the pressure in the first pressing process (second pressing process). B-4) A step of adjusting the mold temperature to below the melting point if the thermoplastic resin is crystalline, or below the glass transition temperature if the thermoplastic resin is amorphous. By carrying out these steps, an integrally molded structure can be produced.

[0121] 4. Commonalities between cold press molding and hot press molding Steps A-2) and B-3) are steps in which pressure is applied to the composite material to obtain a molded product of the desired shape. The molding pressure is not particularly limited, but is preferably as low as possible within a range that allows the desired structure shape to be obtained. Specifically, a pressure of less than 30 MPa relative to the mold cavity projected area is preferred, more preferably 20 MPa or less, and even more preferably 10 MPa or less. A molding pressure of less than 30 MPa is preferred because it does not require capital investment or maintenance costs for a press. Naturally, various processes may be inserted between the above compression molding steps, such as vacuum compression molding, in which compression molding is performed under vacuum.

[0122] [Manufacturing method of molded products] An example of a manufacturing embodiment is shown below: When upper and lower molds are used as the molds, it is preferable that the first mold is the upper mold (movable mold) and the second mold is the lower mold (fixed mold).

[0123] [Method for manufacturing molded products: Manufacturing embodiment 1: Bending composite material] The molded article of the present invention can be produced by preparing a flat composite material containing reinforcing fibers and a resin, and then press-molding the composite material using a first molding die and a second molding die, thereby pressing and deforming the composite material.

[0124] More specifically, a molding die is prepared in which a second molding die (e.g., a fixed die) is provided with a plurality of recesses, and a first molding die (e.g., a movable die) is provided with a plurality of protrusions, each of which forms a pair of male and female protrusions. A flat composite material containing reinforcing fibers and resin is placed in this second molding die after being heated to above the softening temperature of the resin (Fig. 12(a)). When the first molding die is lowered (Fig. 12(b)) and pressed, the composite material is bent to form recesses in the molded product, and at the same time, the upper die penetrates the recesses (Figs. 12(c)(d)). A molded product can be obtained in which holes h have been formed through these through holes.

[0125] From the viewpoint of molding, it is preferable to apply a molding pressure of 20 MPa or more. However, after forming the holes (h), in consideration of the ease of removing the molded product with the holes (h) from the upper mold, it is better to use a relatively low molding pressure. From this viewpoint, it is preferable to process at a pressure of 10 MPa or less, more preferably 6 MPa or less.

[0126] [Method for manufacturing molded products: Manufacturing embodiment 1-2: Bending composite material] When press molding is performed in the above "Manufacturing Embodiment 1-1", when a recess is formed in the molded product by bending, the composite material may be simply bent by the molding die to make it non-through.

[0127] [Method for manufacturing molded products: Manufacturing embodiment 1-3: Cutting after bending the composite material] A molded product having hole h penetrating through may be produced by subjecting the recessed portion (non-through portion) of the molded product produced in the above "Manufacturing Embodiment 1-2" to secondary processing using a drill or the like to form a through hole. In this case, the cut is made so as to leave the peripheral portion having the protrusion.

[0128] [Method for manufacturing molded products: Manufacturing embodiment 2: Bending the composite material after drilling the pre-holes] The molded article of the present invention is preferably prepared by preparing a flat composite material containing reinforcing fibers and a resin, forming a plurality of pre-holes in the composite material, and then press-molding the composite material using a first mold and a second mold to press-deform the pre-holes formed in the composite material to form the holes h. When press-deforming, the composite material is preferably bent as described in "Manufacturing Embodiment 1-1" so as to widen the pre-holes, thereby forming the holes h. Preferably, two or more pre-holes are formed simultaneously by a punching process, and the punching process is repeated two or more times.

[0129] The size of the precursor hole is preferably smaller than the hole h of the molded product. If the precursor hole is designed to be smaller than the hole h of the molded product and the composite material is bent and molded so as to form the hole h during molding, the hole h can be easily formed at the periphery. i=k and hole h i=k+1The ends of the reinforcing fibers arranged to connect the holes can be oriented toward one side of the molded product. Smaller precursor holes are preferable because they reduce waste.

[0130] [Weld line] It is preferable that no weld lines occur in the bridge portion. When there are multiple bridge portions, it is preferable that no weld lines occur in at least one bridge portion. It is more preferable that no weld lines occur in all bridge portions provided in the molded product.

[0131] When a molded product like the one shown in Figure 1 is produced by injection molding, weld lines will inevitably appear, significantly reducing the strength of the molded product at the weld lines. On the other hand, in all of the manufacturing embodiments described above, no weld lines appear at any of the bridge portions of the molded product. [Example]

[0132] 1. Evaluation (1) Material Polypropylene resin: Novatec PP BC03C (sometimes abbreviated as PP) manufactured by Japan Polypropylene Corporation Nitto Boseki's E-glass RS240QR-483 glass fiber with a sizing agent attached was prepared (sometimes abbreviated as GF).

[0133] (2) Evaluation method Tensile testing Samples were taken from the molded product as shown in 201 and 202 in Figure 2, and tensile tests were performed in any direction of the molded product and in the direction perpendicular to this. The tensile conditions were in accordance with ASTM D3039, and a universal testing machine was used to perform the 0° tensile test at a test speed of 2 mm / min.

[0134] (3) Observation of fiber orientation The area around the hole of the molded product was cut out to prepare a 100mm x 100mm sample. The sample was heated to 500°C in air for 1 hour in an electric furnace (FP410 manufactured by Yamato Scientific Co., Ltd.) to burn off organic materials such as the matrix resin. The sample was then observed to determine the fiber orientation.

[0135] (4) The area ratio Cf of the cross section of the reinforcing fiber exposed on the inner wall surface C of the hole h The inner wall surface of the molded product is observed under an optical microscope, and 10 areas of 0.1 mm x 0.1 mm are randomly selected to measure the area ratio of the cross-section of the reinforcing fiber within each area. The average value of the area ratios of the cross-sections of the reinforcing fiber selected at the 10 selected locations is taken as the area ratio Cf.

[0136] (5) Fiber volume fraction Vf contained in the entire molded product The molded product was placed in a furnace at 500°C for 1 hour to burn off the thermoplastic resin, and the mass of the reinforcing fiber and resin was calculated by weighing the sample before and after treatment. Next, the volume ratio of the reinforcing fiber to the resin was calculated using the specific gravity of each component. Note that the amount of other additives was so small that they could be ignored in terms of volume. Vf = 100 x reinforcing fiber volume / (reinforcing fiber volume + resin volume + other additive volume)

[0137] [Example 1] (1) Preparation of composite material The glass fiber used was Nitto Boseki's E-glass RS240QR-483 glass fiber cut to a fiber length of 20 mm, and the resin used was polypropylene resin Novatec PP BC03C manufactured by Japan Polypropylene Corporation, to prepare a composite composition of glass fiber and polypropylene resin in which the glass fibers were oriented two-dimensionally randomly based on the method described in U.S. Patent No. 10,006,677. The resulting composite composition was heated at 2.0 MPa for 5 minutes in a press heated to 250°C, and a flat plate-shaped composite material measuring 600 mm x 1000 mm with an average thickness of 3 mm was prepared.

[0138] (2) Creating a molded product with hole h A molded product was prepared using the above [Manufacturing Embodiment 1-1]. (2-1) Press molding The following molds were prepared: First molding die: A movable die having a cylindrical convex portion with a diameter of 42 mm. · Second molding die: A fixed die with a recess formed to form a male-female pair with the first molding die, the inside of the recess being circular with a diameter of 44 mm. The flat composite material thus prepared was heated above the softening point of the resin to soften it, and then placed in a second mold and press-molded at a pressure of 20 MPa to bend the composite material and create a non-penetrating recess. The results are shown in Table 1, and the results of the tensile test are shown in FIG.

[0139] [Comparative Example 1] Holes were made in the composite material prepared in Example 1 using a punching plate. The results are shown in Table 1.

[0140] [Table 1] [Explanation of symbols]

[0141] 101: Hole h 102: Base section 103: Periphery 105: Bridge section 107: Peripheral area width L2: The shortest distance between holes h and h2 (the shortest width of the bridge part) 201: Cutting out a sample of the molded product to measure the degree of two-dimensional random orientation 202: Cutting out a sample of the molded product in a direction perpendicular to the sample in 201 401:Protrusion L1: Height of the protrusion t1: Average thickness of the base r1: inner diameter of protrusion r2: outer diameter of the protrusion 501: Reinforced fibers are arranged continuously 502: Periphery 503: End of reinforcing fiber oriented on one side C: Inner wall surface V1: Volume of the protrusion V2: Volume expressed as the projected area Si of hole h × the average thickness t1 of the base portion. This can also be said to be the volume of the region hp where hole h is to be formed in the composite material before hole h1 is formed.

Claims

1. A molded article comprising discontinuous reinforcing fibers and a resin, The molded product has a plurality of holes h and a base portion, The base part has a hole ｉ＝ｋ and hole h ｉ＝ｋ＋１ The bridge portion has a bridge portion sandwiched between the holes h ｉ＝ｋ and the hole h ｉ＝ｋ＋１ and a region in which reinforcing fibers are continuously arranged so as to connect the the base portion has a peripheral edge portion along the peripheral edge of the hole h, the peripheral edge portion has a protrusion portion, and the protrusion portion protrudes from one surface side of the molded product; Molded products.

2. The molded article according to claim 1, wherein 0.5 × V2 < V1 ≦ V2 is satisfied. V1: Volume of the protrusion V2: Projected area Si of hole h × average thickness t1 of base portion

3. The molded article according to claim 1 or 2, wherein L1<r1. however, L1: Height L1 of the protrusion r1: Radius of the maximum inscribed circle of hole h is.

4. The molded article according to any one of claims 1 to 3, wherein L2 < L1. however, L1: height of the protrusion L2: The shortest width of the bridge section

5. 5. The molded product according to claim 4, wherein the length L2 of the shortest bridge width of the bridge portion is 3.0 mm or more and 8.0 mm or less. is.

6. The molded article according to any one of claims 1 to 5, wherein S1 < S2. however, S1: Projected area of ​​the base S2: Hole h represented by the following formula (A) ｉ＝ｋ The sum of the projected areas Si of [Equation 1] is.

7. the molded product is an integrally molded product, and the protrusion portion forms a cylinder; For the reinforcing fibers included in the protrusions, the tensile breaking stress F1 in the ring direction of the tube and the tensile breaking stress F2 in the height direction of the tube satisfy F1>F2. The molded article according to any one of claims 1 to 6.

8. In the protrusion of the molded product, When observing a cross section parallel to the base portion, the number of cross sections of reinforcing fibers per unit area N1, When observing a cross section perpendicular to the base portion, the number of cross sections of the reinforcing fibers per unit area N2 is N1>N2 is satisfied. The molded article according to any one of claims 1 to 7.

9. The molded article according to claim 1 , wherein the molded article exhibits isotropic tensile stress at break.

10. The weight average fiber length Lw of the reinforcing fiber is 1 mm or more and 100 mm or less, The molded product includes reinforcing fibers longer than the shortest bridge width of the bridge portion, The resin is a thermoplastic resin, The molded article according to any one of claims 1 to 9.

11. The molded product according to any one of claims 1 to 10, wherein the holes h are arranged in a honeycomb pattern.

12. The molded product according to claim 1 , wherein reinforcing fibers are continuously arranged in all of the bridge portions included in the molded product.

13. The molded product according to claim 12, wherein no weld line is formed in the bridge portion.

14. A method for producing the molded article according to any one of claims 1 to 13 by press-molding a flat composite material containing reinforcing fibers and a resin, wherein the method satisfies 0.5 x V2 < V1 ≦ V2. V1: Volume of the protrusion V2: Projected area of ​​hole h × thickness of base

15. A method for producing the molded product according to any one of claims 1 to 13 by press-molding a flat composite material containing reinforcing fibers and a thermoplastic resin, wherein the composite material has a region hp where the hole h is to be formed and a region Bp where the bridge is to be formed, Step A-101: Heating the region hp, Step A-201: The composite material having the heated region hp is press-molded using a first mold and a second mold to deform the composite material and form the hole h. A method for producing a molded article.

16. The method for manufacturing a molded product according to claim 15, wherein the predetermined formation regions hp are arranged in a plurality of rows, In the step A-101, an arbitrary row of the formation planned region hp is heated using an infrared heating device, and then press-molded in the step A-201, Returning to A-101 again, the next row of the formation planned region hp is press-molded using the infrared heating device, A method for continuously manufacturing molded products.

17. A method for producing the molded article of claim 15, comprising the steps of: In the step A-101, the region Bp is not heated to a temperature higher than the softening temperature of the resin. A method for producing a molded article.

18. A method for producing the molded article according to any one of claims 14 or 15, comprising the steps of: After providing a plurality of precursor holes in the composite material, the composite material is press-molded using a first molding die and a second molding die, thereby pressing and deforming a precursor hole provided in the composite material to form the hole h; A method for producing a molded article.

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