Method for manufacturing resin component

Abstract

To provide a method for manufacturing a resin component capable of applying a pressure as uniform as possible to a molding material without using a complicated manufacturing apparatus even when the resin component having a complicated shape is manufactured.SOLUTION: A method of manufacturing a resin component by compression-molding a forming material using a forming die MA and a forming die MB which are a pair of female and male forming dies, wherein the forming material includes discontinuous reinforcing fibers and resins, a side A1 of one surface of the forming material has a repeating structure of an uneven shape, a side B1 of an opposite surface has a repeating structure of an uneven shape so as to correspond to repetition of unevenness of the side A1 of one surface, and the side A1 of one surface and the side B1 of the opposite surface of the forming material are compression-molded to form a side A2 of one surface and a side B2 of the opposite surface of the resin component, respectively.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a resin part. [Background technology]

[0002] When manufacturing a resin part by compression molding, it is desirable to uniformly apply pressure to the molding material.

[0003] The invention described in Patent Document 1 relates to a device that equalizes the pressure from the hot platens to the mold during press molding. Specifically, the pressure equalizing device, which is placed between the hot platens and the mold, includes a push-side member on the hot platen side and a receiving-side member with a recess on the mold side. This push-side member is designed to contain fluid within the recess in the receiving-side member and transmit the pressure from the hot platens to the receiving-side member via that fluid, thereby equalizing the pressure applied to the mold and enabling the production of high-quality molded products.

[0004] The invention described in Patent Document 2 relates to the development of a mold base used when molding elastic materials, and provides a simple, low-cost structure that can evenly distribute the surface pressure of the molding die. The mold base is grooved, and when the molding die is tightened into the press, these grooves elastically deform to evenly distribute the surface pressure. In particular, the grooves on the mold base are formed in a grid pattern and are arranged in a staggered pattern on the front and back flat surfaces, so that they are not exposed on the sides of the mold base. This is expected to contribute to improving the quality of molded products and reducing manufacturing costs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-6397 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-231273 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the invention described in Patent Document 1 requires molding via a fluid, which makes the structure of the molding device complex. Also, the invention described in Patent Document 2 requires the use of a metal base with grooves, which also makes the structure of the molding device complex.

[0007] Therefore, in this invention, we focus on the shape of the molding material rather than the manufacturing equipment, and we have devised a method for manufacturing resin parts that can apply as uniform pressure as possible to the molding material, even when manufacturing resin parts with complex shapes, without using complex manufacturing equipment. [Means for solving the problem]

[0008] As a result of extensive investigations, the present inventors have found that the above problems can be solved by the following means, and have arrived at the present invention. 1. A method for producing a resin part by compression molding a molding material using a pair of male and female molds, mold MA and mold MB, The molding material includes discontinuous reinforcing fibers and a resin, One side A1 of the molding material has a repeating uneven structure, and the other side B1 has a repeating uneven structure corresponding to the repeating uneven structure of the one side A1, One side A1 and the other side B1 of the molding material are compression molded to form one side A2 and the other side B2 of the resin part, respectively. Manufacturing method for plastic parts. 2. The uneven shape of one side A1 is compression molded to form a top surface, a vertical surface, and a bottom surface on one side A2 of the resin part, and the top surface, the vertical surface, and the bottom surface form a repeating structure on one side A2 of the resin part; The concave and convex shape of the opposite surface B1 is compression molded to form a lightening portion corresponding to the top surface portion on the opposite surface B2 of the resin part. 2. A method for manufacturing a resin part according to item 1 above. 3. The method for manufacturing a resin part according to 2 above, wherein the hollowed-out portion forms a repeating structure. 4. The method for manufacturing a resin part according to any one of 1 to 3 above, wherein the discontinuous fibers have a weight average fiber length of 1 mm or more and 100 mm or less and are dispersed in the in-plane direction of the molding material. 5. When the plate thickness of the molding material in the region where the convex portion of the concavo-convex shape of the one surface A1 is formed is tc1 and the plate thickness tc2 of the molding material in the region where the concave portion of the concavo-convex shape of the one surface A1 is formed, the method for manufacturing a resin part according to any one of 1 to 4 above, which satisfies tc1×0.8 < tc2 < tc1×1.2. 6. When the thickness of the molding material in the region of the standing surface portion of the one surface A2 of the resin part is tc3, the method for manufacturing a resin part according to 5 above, which satisfies tc1×0.7 < tc3 < tc1×1.3. 7. A method for manufacturing a structure having the resin part obtained by the manufacturing method according to any one of 2 to 6 above and a metal part, wherein at least a part of the metal part is arranged on the outer surface of the resin part along the top surface portion or the bottom surface portion, the method for manufacturing a structure. 8. The metal part has a turning portion in which the direction of extension on the outer surface is changed, and the resin part and the metal part are fixed to the resin part at the turning portion, the method for manufacturing a structure according to 7 above. 9. The method for manufacturing a structure according to any one of 7 or 8 above, wherein at least a part of the metal part is arranged along the top surface portion. 10. The metal part has a first portion extending in a first in-plane direction and a second portion extending in a second in-plane direction different from the first in-plane direction, wherein the turning portion connects the first portion and the second portion, the method for manufacturing a structure according to any one of 7 to 9 above. 11. The method for manufacturing a structure according to 10 above, wherein the first in-plane direction and the second in-plane direction are perpendicular to each other. 12. The method for manufacturing a structure according to any one of 7 to 10 above, wherein the relationship between the height difference h between the top surface portion and the bottom surface portion and the flatness Fa of the resin part is 0 < Fa / h < 1.3. 13. A method for manufacturing a battery tray or a protective cover for a battery tray according to any one of 7 to 11 above, wherein the metal part is an electrical circuit for impact detection, and the structure is a battery tray or a protective cover for a battery tray. 14. The method for manufacturing an inverter box according to any one of 7 to 11 above, wherein the metal part is an electric circuit and the structure is an inverter box. 15. The method for manufacturing a wireless power supply box according to any one of 7 to 11 above, wherein the structure is a wireless power supply box. [Effects of the Invention]

[0009] According to the method for manufacturing a resin part of the present disclosure, even if the molding material has an uneven thickness structure with uneven shapes, pressure can be applied evenly to the molding material during compression molding. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an example of a resin part of the present invention. [Figure 2] An example of a conventional resin part. [Figure 3] 1 is an example of a structure obtained by the present invention. [Figure 4] 3 is a schematic diagram for explaining the draft angle and the thickness of the molding material of the vertical portion 303. FIG. [Figure 5] FIG. 1 is a schematic diagram showing the manufacturing of a resin part using a pair of male and female molding dies. [Figure 6A] FIG. 6A is a cross-sectional view of a resin part for explaining the flatness Fa. [Figure 6B] FIG. 6B is a cross-sectional view of a resin part for explaining the flatness Fa. [Figure 7] FIG. 10 is a cross-sectional view of a resin part for explaining the difference h in thickness between the top surface and the bottom surface. [Figure 8] FIG. 4 is a schematic diagram showing a protective cover for a battery tray. [Figure 9] FIG. 1 is a schematic diagram showing a structure as an inverter box. [Figure 10]FIG. 1 is a plan view showing a structure having a resin part and a metal part. DETAILED DESCRIPTION OF THE INVENTION

[0011] First, a method for manufacturing a resin part according to the present disclosure will be described. A method for producing a resin part by compression molding a molding material using a pair of male and female molds, mold MA and mold MB, comprising: The molding material includes discontinuous reinforcing fibers and a resin, One side A1 of the molding material has a repeating uneven structure, and the other side B1 has a repeating uneven structure corresponding to the repeating uneven structure of the one side A1, One side A1 and the opposite side B1 of the molding material are compression molded to form one side A2 and the opposite side B2 of the resin part, respectively.

[0012] [Shape of molding material] FIG. 1 illustrates a cross-sectional view of a molding material of the present invention. To form a repeating structure with a top surface, a vertical surface, and a bottom surface in a resin part, molding material 101 has a repeating uneven structure on one side A1, and a repeating uneven structure on the opposite side B1 that corresponds to the repeating unevenness of the one side A1. In other words, even if the molding material of the present invention has an uneven shape on one side A1, there is no deviation in the thickness of the molding material as a whole. This is because there are recesses on the opposite side B1 that correspond to the protruding portions of the uneven shape on one side A1, and there are protruding portions on the opposite side B1 that correspond to the recessed portions of the uneven shape on one side A1.

[0013] Here, when the plate thickness of the molding material in the region forming the convex portion of the uneven shape on one side A1 is tc1, and the plate thickness of the molding material in the region where the concave portion of the uneven shape is formed on one side A1 is tc2, it is preferable to satisfy tc1×0.8 < tc2 < tc1×1.2. More preferably, tc1×0.9 < tc2 < tc1×1.1, and still more preferably, tc1×0.95 < tc2 < tc1×1.05. When there are multiple locations corresponding to tc1 and tc2, it is preferable that at least one pair of tc1 and tc2 satisfies the above relationship, more preferably that half of the tc1 and tc2 satisfy the above relationship, and still more preferably that all of the tc1 and tc2 satisfy the above relationship.

[0014] The thickness of tc1 is preferably 10 mm or less, more preferably 5 mm or less, and still more preferably 3 mm or less. Similarly, the thickness of tc2 is preferably 10 mm or less, more preferably 5 mm or less, and still more preferably 3 mm or less.

[0015] Thus, by providing an uneven shape on the opposite surface B1 so as to correspond to the unevenness on one side A1, the clearance of the molding die cavity can be kept at a substantially constant length. If the clearance in the molding cavity becomes constant, the pressure applied to the molding material during compression molding also becomes uniform. A schematic diagram of the molding die is shown in FIG. 5. The molding material 101 is sandwiched between the upper molding die 501 and the lower molding die 502 and is being compression molded. Since there is no significant difference between the thickness of 503 in FIG. 5 and the thickness of 504 in FIG. 5, it is easy to apply pressure uniformly to the molding material 101 within the molding die cavity.

[0016] On the other hand, when creating a resin part using the molding material 201 of the conventional design depicted in FIG. 2 in order to form a repeating structure with a top surface portion, a standing surface portion, and a bottom surface portion in the resin part, since the molding material has an obvious uneven wall thickness structure, it is difficult to apply pressure uniformly within the molding cavity during compression molding.

[0017] In order to facilitate the removal of the resin part after molding, the draft angle 401 is preferably 5 degrees or more, more preferably 10 degrees or more. The draft angle 401 is defined as "the angle of -90 degrees formed by the vertical surface and the bottom surface on one side A2 of the resin part (401 in FIG. 4)". Similarly, the draft angle 402 is preferably 5 degrees or more, more preferably 10 degrees or more. The draft angle 402 is defined as "the angle of -90 degrees formed by the vertical surface 403 of the knockout part and the bottom surface 404 of the knockout part in the knockout part on the opposite surface B2 of the resin part (402 in FIG. 4)".

[0018] [Thickness tc3] When the thickness of the molding material in the region of the vertical surface portion on one side A2 of the resin part is tc3 (see FIG. 4), it is preferable to satisfy tc1×0.7 < tc3 < tc1×1.3. More preferably, tc1×0.8 < tc3 < tc1×1.2, still more preferably tc1×0.9 < tc3 < tc1×1.1, and even more preferably tc1×0.95 < tc3 < tc1×1.05. When there are multiple locations corresponding to tc1 and tc3, it is preferable that at least one pair of tc1 and tc3 satisfy the above relationship, more preferably that half of the tc1 and tc3 satisfy the above relationship, and even more preferably that all of the tc1 and tc3 satisfy the above relationship. The thickness of tc3 is preferably 10 mm or less, more preferably 5 mm or less, and still more preferably 3 mm or less. By designing the thickness of tc3 in this way, in addition to the regions of the top surface portion and the bottom surface portion, pressure can be uniformly applied in the molding cavity during compression molding in the region of the vertical surface portion as well.

[0019] [Reinforcing fiber] In this specification, the reinforcing fiber is preferably at least one selected from the group consisting of carbon fiber, aramid fiber, and glass fiber. More preferably, the reinforcing fiber is carbon fiber or glass fiber.

[0020] [Reinforcing 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.

[0021] 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, and is not particularly limited. 3. Carbon fiber and electrolytic corrosion prevention measures When carbon fiber is used, an adhesive layer disposed between the resin part and the metal layer serves as a countermeasure against electrolytic corrosion.

[0022] [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 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.

[0023] 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.

[0024] [Reinforced fiber: fiber length] The reinforcing fibers in the present invention are discontinuous fibers. When discontinuous fibers are used, the formability is improved compared to fiber-reinforced plastics that use only continuous fibers, making it easier to create complex resin parts. Since the weight-average fiber length of the reinforcing fibers does not change before and after molding, the weight-average fiber length Lw of the reinforcing fibers contained in the molding material can be determined by examining the weight-average fiber length of the reinforcing fibers in the plastic part. The weight-average fiber length Lw of the reinforcing fibers is preferably 1 mm or more, more preferably 3 mm or more. The weight-average fiber length Lw of the reinforcing fibers is more preferably 3 mm or more and 100 mm or less, more preferably 3 mm or more and 80 mm or less, and even 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 fluidity of the molding material is less likely to decrease when the molding material is compression molded, making it easier to produce the desired shape. Furthermore, if the weight-average fiber length Lw is 1 mm or more, the mechanical strength of the resulting resin part is less likely to decrease, which is preferable.

[0025] 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 a resin part made 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 make the resin part by compression molding.

[0026] 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.

[0027] [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.

[0028]

number

[0029] Here, "I" indicates the number of reinforcing fibers measured. 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 resin parts by, for example, performing a heat treatment at 500°C for about 1 hour and removing the resin in a furnace.

[0030] The average fiber length can be calculated, for example, by measuring the fiber lengths of 100 fibers randomly extracted from a resin part to the nearest 1 mm using a caliper or the like, and then calculating the average fiber length based on formula (1) or formula (2).

[0031] 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.

[0032] [Reinforced fibers: Dispersed in the in-plane direction] The reinforcing fibers of the present invention are preferably discontinuous fibers and dispersed in the in-plane direction of the molding material. Furthermore, by dispersing the reinforcing fibers contained in the molding material in the in-plane direction, it is easier to disperse them in the in-plane direction in the resin part as well.

[0033] In the present invention, the molding material is a material for producing a resin part, and the molding material is compression molded to become the resin part. Therefore, the molding material in the present invention has a substantially flat plate shape, while the resin part is shaped and has a three-dimensional shape.

[0034] Dispersion of the reinforcing fibers in the in-plane direction means that the reinforcing fibers are dispersed so that their fiber axes are oriented in the in-plane direction. It is preferable that the angle between the fiber axes of the reinforcing fibers and the in-plane direction is 45° or less.

[0035] 1. In-plane direction The in-plane direction is an indefinite direction of a parallel plane perpendicular to the thickness direction of the molding material or the resin part. The molding material is preferably a plate-shaped material.

[0036] 2. Random distribution in two dimensions It is preferable that the reinforcing fibers are randomly dispersed in the in-plane direction and in two dimensions. In areas where the molding material is compression molded without flow, the shape of the reinforcing fibers is largely maintained before and after molding. Therefore, it is preferable that the reinforcing fibers contained in the non-flowing areas of the resin part molded from the molding material are also randomly dispersed in the in-plane direction and in two dimensions.

[0037] Here, "dispersed two-dimensionally at random" refers to a state in which the reinforcing fibers are not oriented in a specific direction within the in-plane direction of the molding material or resin part, but are oriented randomly, and are arranged within the sheet plane without any specific directionality overall. A molding material (or resin part) obtained using discontinuous fibers dispersed two-dimensionally at random is a substantially isotropic molding material (or resin part) that does not have anisotropy within the plane.

[0038] The degree of two-dimensional random orientation is evaluated by determining the ratio of the tensile modulus in two mutually perpendicular directions. If the ratio (Eδ) obtained by dividing the larger of the tensile modulus values ​​measured in any direction of the resin part (or molding material) and the direction perpendicular to that direction by the smaller 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 dispersed two-dimensionally randomly.

[0039] If the resin contained in the resin part is a thermoplastic resin and the resin part is a three-dimensional part with a curved surface, a good method for evaluating two-dimensional random dispersion in the in-plane direction is to heat the resin part above its softening temperature, return it to a flat plate shape, and then solidify it. Then, by cutting out a test piece and measuring the tensile modulus, the state of random dispersion in the two-dimensional direction can be confirmed.

[0040] [Reinforced fiber: fiber volume ratio] Although there is no particular limitation on the fiber volume fraction Vf of the reinforcing fibers, 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.

[0041] 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 from the resin part and the resin is burned off in a furnace at 500°C for 1 hour. The mass of the sample is then weighed before and after treatment to calculate the mass of the reinforcing fiber, resin, and other additives. Next, the specific gravity of each component is used to calculate the volume ratio of the reinforcing fiber to the resin: Vf = 100 x reinforcing fiber volume / (reinforcing fiber volume + resin volume + other additives).

[0042] [resin] The resin contained in the resin part may be thermosetting or thermoplastic. 1.Thermoplastic resin When the resin used is a thermoplastic resin, the type thereof 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.

[0043] 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.

[0044] The thermoplastic resin used in the resin part of the present invention may be one type or two or more types. 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. When a thermoplastic resin is used, it is more preferable to use a polyolefin resin, and even more preferable to use a polypropylene resin.

[0045] 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.

[0046] Furthermore, when a thermosetting resin is used as the resin of the present invention, a sheet molding compound (sometimes referred to as SMC) containing reinforcing fibers may be used. Due to its high moldability, a sheet molding compound can be easily molded into even complex shapes. Compared to continuous fibers, a sheet molding compound has higher fluidity and shaping properties, making it easy to create ribs and bosses.

[0047] [Other agents] The resin used in the molding material may contain additives such as various fibrous or non-fibrous fillers, such as organic or inorganic fibers, flame retardants, UV-resistant agents, stabilizers, mold release agents, pigments, softeners, plasticizers, surfactants, etc., in addition to the discontinuous reinforcing fibers of the present invention, as long as the object of the present invention is not impaired. When a thermosetting resin is used, it may 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.

[0048] [Shape of molding material] The molding material before molding is preferably a flat plate-shaped molding material.

[0049] [Manufacturing method for resin parts: compression molding] 1. Hot press molding and cold press molding When producing the resin part of the present invention, a molding material containing discontinuous reinforcing fibers and a resin can be produced by compression molding (also called press molding), and molding methods such as hot press molding and cold press molding can be used as compression molding. By press molding the molding material, various shapes can be given to the resin part. Resin parts produced by compression molding are preferably monolithic structures.

[0050] 2.Cold press molding When a molding material containing a thermoplastic resin is used as the resin, compression molding using cold press is preferred. In cold press molding, for example, a molding material heated to a first predetermined temperature is placed in a mold set to a second predetermined temperature, and then pressurized and cooled.

[0051] Specifically, if the thermoplastic resin contained in the molding 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). 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. Step A-2) The molding 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 molding material can be completed (a resin part that is a compressed structure can be produced).

[0052] 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. The shape of the molding material may be a shape developed by computer through inverse molding analysis from the three-dimensional shape of the compression molded product to be manufactured.

[0053] 3.Hot press molding In hot press molding, for example, a molding material is placed in a mold, pressure is applied while the temperature of the mold is raised to a first predetermined temperature, and the mold is cooled to a second predetermined temperature. Specifically, if the thermoplastic resin constituting the molding 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 contained in the molding 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. Hot press molding preferably includes at least the following steps B-1) to B-4). B-1) A step of placing the molding material in the 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.

[0054] 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 molding material to obtain a resin part 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 resin part 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.

[0055] 5. The present invention is a method for producing a resin part by compression molding using a pair of male and female molds, mold MA and mold MB. Here, the term "male and female pair" does not mean that each mold is a pair of male and female molds, but rather that mold MA and mold MB are halves that form a male-female pair. Furthermore, it is sufficient that one half of the mold has a male part and the other half has a female part, and both molds may have male and female (convex and concave or concave and concave).

[0056] [Resin parts] The resin part obtained by compression molding will be explained with reference to FIG. One side A1 and the opposite side B1 of the molding material are compression molded to form one side A2 and the opposite side B2 of the resin part, respectively. The uneven shape of one side A1 is compression molded to form a top surface portion 302, a vertical surface portion 303, and a bottom surface portion 304 on one side A2 of the resin part, and the top surface portion 302, the vertical surface portion 303, and the bottom surface portion 304 form a repeating structure on one side A2 of the resin part. In other words, the resin part 301 has a top surface portion 302 and a bottom surface portion 304 that is dug down from the top surface portion 302.

[0057] Furthermore, by molding the uneven shape on the opposite surface B1, the opposite surface B2 of the resin part is provided with a lightening portion corresponding to the top surface portion. It is preferable that one surface A1 of the molding material has a repeated uneven structure, and by providing a repeated uneven shape on the opposite surface B1 that corresponds to the repeated unevenness, the opposite surface B2 of the molded resin part is provided with a lightening portion 305 that corresponds to the top surface portion 303. It is more preferable that the lightening portion 305 is formed by compression molding the uneven shape on the opposite surface B1 of the molding material.

[0058] Although one side A2 and the other side B2 have an uneven shape, when viewed from above, the resin part 301 has a generally flat plate shape. When the metal component 302 is arranged along the top surface 302, it is preferable that the outer surface of the top surface 302 on which the metal component 302 is arranged is flat. The thickness of resin part 301 is not particularly limited, but is, for example, 0.5 mm to 10.0 mm, and preferably 1.0 mm to 8.0 mm. The thickness of resin part 301 here is defined as the distance between two ideal parallel lines drawn with the minimum necessary vertical width so as to include all of the irregularities on one side A2 and the irregularities on the opposite side B2.

[0059] [Structure] 1. Placement of metal parts The resin part of the present invention is preferably a method for manufacturing a structure having a resin part and a metal part, and it is preferable that at least a portion of the metal part is arranged on the outer surface of the resin part along the top or bottom surface of the resin part. It is also preferable that the metal part has a redirection portion where the direction of extension on the outer surface is changed, and that the resin part and the metal part are fixed to each other at the redirection portion.

[0060] When fabricating a structure in which a metal part is placed on a resin part, the metal part may lift up in the thickness direction (the direction perpendicular to the outer surface of the resin part). Furthermore, when the metal part cools, the deflection part is subject to contraction forces with different vectors, making the deflection part particularly susceptible to lifting. In the structure of the present invention, the deflection part of the metal part is fixed to the resin part, thereby reducing the lifting of the metal part. At least a portion of the metal component may be disposed along the bottom surface portion, and at least a portion of the metal component may be disposed along the top surface portion.

[0061] 2. Direction change section The change portion will be described with reference to FIG. 10. FIG. 10 is a plan view showing an example of a structure. The metal part has a first portion 1002 extending in a first in-plane direction and a second portion 1003 extending in a second in-plane direction different from the first in-plane direction, and a deflection portion 1005 preferably connects the first portion and the second portion. The deflection portion connecting the first portion and the second portion extending in different directions is particularly prone to lifting up. According to a structure as an example of the present invention, such a deflection portion is fixed (1004 in FIG. 10), so lifting up can be effectively reduced.

[0062] The first in-plane direction and the second in-plane direction may be perpendicular to each other. When the structure according to the present invention has a shape that bends perpendicularly at the deflection section, the effect of reducing lifting by fixing the deflection section is particularly high. In addition, the degree of freedom in arranging the metal parts is high.

[0063] [Metal parts] The metal part 302 is a metal plate disposed on the outer surface of the resin part 301. As shown in FIG. 10 , the structure 1001 includes the resin part 301 and the metal part 302, and the metal part 302 is disposed on the outer surface of the resin part 301. The metal part 302 is disposed in an accordion-like shape on one side A2 of the resin part 301 and is configured to widely cover the main surface of the resin part 301. At least a portion of the metal part 302 is disposed on the outer surface of the resin part 301 along the top surface 302 or the bottom surface 304. In the structure 1001 of FIG. 3 , the metal part 302 is disposed along the top surface 302 of the resin part 301, more specifically, on the top surface 302.

[0064] 10 , metal part 302 has a redirection portion 1005 in which the direction of extension on the outer surface is changed. More specifically, metal part 302 has a first portion 1002 extending in the up-down direction of the paper (hereinafter referred to as the first in-plane direction) and a second portion 1003 extending in the left-right direction of the paper (hereinafter referred to as the second in-plane direction), and first portion 1002 and second portion 1003 are connected at redirection portion 1005. In one example embodiment of the present invention, the rectangular area in which the extended portion of first portion 1002 and the extended portion of second portion 1003 overlap can be considered to be redirection portion 1005.

[0065] There are no particular limitations on the metal material that constitutes the metal component 302, and various metals or alloys can be used depending on the required properties. Examples of metal materials include copper, aluminum, iron, chromium, nickel, manganese, and alloys thereof.

[0066] The shape of the metal component 302 is not limited to a plate shape and can be changed as appropriate depending on the application and configuration. Specifically, the metal component 302 may be a metal wire having a substantially circular cross section, or may be a bundle of stacked or integrated metal wires.

[0067] The thickness of the metal part 302 is not particularly limited and can be changed as appropriate depending on the application and configuration. The thickness of the metal part 302 may be, for example, 0.01 mm to 10 mm, 0.05 mm to 1.0 mm, or 0.10 mm to 0.50 mm. When the metal part 302 is a metal wire, the maximum diameter along the thickness direction of the cross section of the metal wire is considered to be the thickness.

[0068] [Adhesion of resin and metal parts] It is preferable that the resin part 301 and the metal part 302 are fixed to each other at the turning portion 1005 of the metal part 302 .

[0069] The structure 1001 can reduce the floating of the metal component 302 by fixing the resin component 301 and the metal component 302 to each other at the turning portion 1005 where the metal component 302 is likely to float up.

[0070] Furthermore, in a preferred structure 1001, the first in-plane direction and the second in-plane direction of the metal component 302 are perpendicular to each other. When the first in-plane direction and the second in-plane direction of the metal component 302 are perpendicular to each other, the deflection portion 1005 connecting the first portion 1002 and the second portion 1003 is particularly likely to lift up. Therefore, by fixing the resin component 301 and the metal component 302 at the deflection portion 1005, it is possible to effectively reduce the lifting of the metal component 302. Furthermore, when it is desired to widely cover the outer surface of the resin component 301 with the metal component 302, the degree of freedom in arranging the metal component 302 can be increased by making the first in-plane direction and the second in-plane direction perpendicular to each other.

[0071] In the cross-sectional view perpendicular to the outer surface of the resin component 301, it is preferable that the top surface portion 302 and the bottom surface portion 304 are alternately positioned. Note that the "cross-section perpendicular to the outer surface of the resin component 301" is not uniquely determined, but when the top surface portion 302 and the bottom surface portion 304 are alternately positioned in any cross-sectional view perpendicular to the outer surface of the resin component 301, it is regarded as "in the cross-sectional view perpendicular to the outer surface of the resin component 301, the top surface portion 302 and the bottom surface portion 304 are alternately positioned". More preferably, the top surface portion 302 and the bottom surface portion 304 are alternately positioned in all cross-sectional views perpendicular to the outer surface passing through the center of gravity of the resin component 301.

[0072] [Relationship between the height difference h between the top surface portion and the bottom surface portion and the flatness Fa] When at least a part of the metal component 302 is arranged along the top surface portion 302 or the bottom surface portion 304, and in the cross-sectional view perpendicular to the outer surface of the resin component 301, the top surface portion 302 and the bottom surface portion 304 are alternately positioned, it is preferable that the relationship between the height difference h between the top surface portion and the bottom surface portion and the flatness Fa of the resin component is 0 < Fa / h < 1.3. The flatness Fa is defined by the following procedures 1 to 5. (Procedure 1) The resin component 301 is placed still so that the surface of the top surface portion 302 on which the metal component 302 is arranged (hereinafter sometimes simply referred to as the "arrangement surface") is on the lower side. (Procedure 2) Observe the cross-section of the resin component 301 in the cross-sectional view where the top surface portion 302 and the bottom surface portion 304 are alternately positioned. Cut out the observation range of the resin component 301 so that the length Ly along the direction in which the top surface portion 302 and the bottom surface portion 304 are alternately positioned is 40 cm. (Procedure 3) Pay attention to the arrangement surface of the top surface portion 302 or the bottom surface portion 304 on which the metal component 302 is arranged. (Procedure 4) Draw two parallel ideal straight lines with the minimum necessary vertical width so as to include all the arrangement surfaces. . (Procedure 5) Define the distance between the two ideal straight lines drawn in Procedure 4 as the flatness Fa.

[0073] Steps 1 to 5 will be described with reference to FIGS. 6A and 6B. FIGS. 6A and 6B are drawn on the premise that the metal part 302 is arranged on the top surface 302.

[0074] FIG. 6A shows the resin part 301 placed stationary with the placement surface of the top surface 302 facing downward. The top surface 302 and the bottom surface 304 are alternately positioned along the Y-axis direction in FIG. 6A. The Z-axis direction is the thickness direction of the resin part 301. FIG. 6A is a view obtained by cutting out the observation range of the resin part 301 so that the length Ly along the Y-axis direction is 40 cm and observing the cross-section by the Y-Z plane (Step 2). The placement surface of the top surface 302 where the metal part 302 is arranged is the area shown as 602 in FIG. 6B (Step 3). Two parallel ideal straight lines are illustrated as 601 in FIG. 6A. The two parallel ideal straight lines 601 are drawn so that the distance between them is minimized. In other words, the two parallel ideal straight lines 601 are drawn with the necessary minimum vertical width. Note that in the present disclosure, a method of observing and measuring by reversing the top and bottom of the structure in FIG. 6A and observing in a state where the surface of the bottom surface 304 is in contact with the table is not adopted.

[0075] When the flatness Fa changes depending on the observation range, if there is a part that satisfies 0 < Fa / h < 1.3 even at one point, it is considered that 0 < Fa / h < 1.3 is satisfied on the placement surface of the top surface 302.

[0076] The difference h in thickness between the top surface 302 and the bottom surface 304 refers to the depth of the groove when observing the cross-section where the top surface 302 and the bottom surface 304 are alternately positioned, as illustrated in FIG. 7. When the height h varies depending on the measurement position, if h at at least one measurement position satisfies 0 < Fa / h < 1.3, it is considered that 0 < Fa / h < 1.3 is satisfied on the placement surface of the top surface 302.

[0077] When Fa / h = 0, the placement surface of the top surface portion 302 on which the metal component 302 is placed is a completely flat plane, that is, an ideal plane. When the placement surface of the top surface portion 302 satisfies 0 < Fa / h, it means that the resin component 301 is warped so as to be convex toward the metal component 302. If 0 < Fa / h, the metal component 302 can be pulled in the plane direction of the resin component 301 (the Y direction in FIG. 6A), and the lifting of the metal component 302 from the resin component 301 can be further reduced.

[0078] If Fa / h < 1.3, it is easy to combine with other components. For example, the assembly of an automobile is easy. More preferably, 0 < Fa / h ≤ 1.0, still more preferably 0 < Fa / h ≤ 0.7, even more preferably 0 < Fa / h ≤ 0.4, and most preferably 0 < Fa / h ≤ 0.1.

[0079] A preferred value of Fa is 0 mm or more and less than 30 mm, more preferably more than 0 mm and less than 20 mm, still more preferably more than 0 mm and less than 15 mm, even more preferably more than 0 mm and less than 10 mm, and most preferably more than 0 mm and less than 5 mm.

[0080] A preferred value of h is more than 0 mm and less than 30 mm, more preferably more than 0 mm and less than 20 mm, still more preferably more than 0 mm and less than 15 mm, even more preferably more than 0 mm and less than 10 mm, and most preferably more than 0 mm and less than 5 mm.

[0081] [Shock detection sensor] The metal component in the present invention is an electric circuit for shock detection, and it is preferable that the structure is a battery tray or a protective cover of a battery tray. FIG. 8 illustrates a protective cover (801) of a battery tray and an electric circuit (802) for shock detection.

[0082] Batteries installed in electric vehicles are heavy, so to achieve a low center of gravity, they are placed under the vehicle floor, protected by the vehicle structure. During high-speed driving, flying stones and other objects can damage the batteries installed in the vehicle, and at low speeds, they can also be damaged by contact with the ground during parking maneuvers. Therefore, electric vehicles often have sturdy battery trays, or a battery tray protective cover is installed under the battery tray to protect the battery box from underneath. In such cases, in the event of an impact, it was traditionally the driver who decided whether the vehicle needed to be inspected at a repair shop. However, because it is difficult to see underneath the vehicle, an expert's eye is required to accurately assess the damage, making it difficult to accurately estimate the extent of the impact.

[0083] Therefore, by using the metal parts of the present invention as an electrical circuit for impact detection, it is possible to detect an impact, classify the impact level, and warn the driver if the impact is completely destroyed. This can prevent holes from opening in the battery tray or its protective cover, which could lead to a battery fire. Furthermore, the electrical circuit can more specifically identify the damaged area, allowing battery management to empty the cells in the damaged area and prevent the risk of fire.

[0084] [Inverter box] The metal part in the present invention is preferably an electric circuit, and the structure is preferably an inverter box. An inverter is a device that converts direct current (DC) supplied from a battery into alternating current (AC), and an inverter box is a housing for the device. In the structure of the present invention, the current circuit is insert-molded into a recess, and it is preferable that a metal part is placed in this recess and fixed to a resin part. An example of a structure as an inverter box is shown in Figure 9. The inverter box is 901 in Figure 9, and an electric circuit (902) is embedded in the bottom part (904).

[0085] [Wireless power supply box] The structure may be a wireless power box. A wireless power box is a technology that transmits power without connecting a power source or wires. For example, the electromagnetic induction method makes it possible to transmit power contactlessly from a transmitting coil to a receiving coil. Wireless power transfer is used to charge smartphones and electric vehicles, and offers many benefits, such as eliminating the need for cables and connectors, improving waterproof and dustproof properties, and improving design. [Industrial Applicability]

[0086] The structure and method for manufacturing the structure of the present disclosure can be applied to parts of various moving objects, industrial machines, etc., such as vehicle impact detection sensors, coils, and planar heating elements. [Explanation of symbols]

[0087] 101: Molding material 102: Convex portion of uneven shape on one side A1 tc1: The thickness of the molding material in the area where one side A1 forms the convex part tc2: The thickness of the molding material in the area where one side A1 forms a recess tc3: Thickness of molding material in the vertical area of ​​one side A2 of the resin part A1: Single side B1: Opposite side 201: Molding material used in conventional technology 301: Resin parts 302:Top section 303: Elevation 304: Bottom part 305: Hollowed-out section 401: On one side A2 of the resin part, the angle between the vertical surface and the bottom surface is -90 degrees 402: In the cutout portion on the opposite surface B2 of the resin part, the angle formed by the vertical surface 403 of the cutout portion and the bottom surface 404 of the cutout portion is −90 degrees 403: Elevation of hollowed-out section 404: Bottom of the hollowed-out section 501: Upper mold 502: Lower mold 503: One side A1 forms the thickness tc1 of the molding material in the region where the convex portion is formed. 504: One side A1 forms a thickness tc2 of the molding material in the area where the recess is formed. 601: Two ideal parallel lines 602: Placement surface of the top surface portion 302 on which the metal component 302 is placed h: Height difference between the top and bottom 801: Battery tray protective cover 802: Electrical circuit for shock detection 901: Inverter box 902: Electrical Circuits 904: Bottom part 1001: Structure 1002: First portion extending in a first in-plane direction 1003: A second portion extending in a second in-plane direction different from the first in-plane direction 1004: Adhesion (The resin part and the metal part are adhered to the resin part at the turning part) 1005: Turning section

Claims

1. A method for producing a resin part by compression molding a molding material using a pair of male and female molds, a molding mold MA and a molding mold MB, comprising: The molding material includes discontinuous reinforcing fibers and a resin, One side A1 of the molding material has a repeating uneven structure, and the opposite side B1 has a repeating uneven structure corresponding to the repeating uneven structure of the one side A1, One side A1 and the opposite side B1 of the molding material are compression molded to form one side A2 and the opposite side B2 of the resin part, respectively. Manufacturing method for plastic parts.

2. The uneven shape of one side A1 is compression molded to form a top surface portion, a vertical surface portion, and a bottom surface portion on one side A2 of the resin part, and the top surface portion, the vertical surface portion, and the bottom surface portion form a repeating structure on one side A2 of the resin part, The concave and convex shape of the opposite surface B1 is compression molded to form a lightening portion corresponding to the top surface portion on the opposite surface B2 of the resin part. The method for manufacturing the resin part according to claim 1.

3. The method for manufacturing a resin part according to claim 2 , wherein the hollowed portions form a repeating structure.

4. The method for manufacturing a resin part according to claim 1 , wherein the discontinuous fibers have a weight average fiber length of 1 mm or more and 100 mm or less, and are dispersed in the in-plane direction of the molding material.

5. 5. A method for manufacturing a resin part according to claim 1, wherein when the thickness of the molding material in the region forming the uneven convex portion of one side A1 is tc1 and the thickness of the molding material in the region forming the uneven concave portion of one side A1 is tc2, the relationship tc1 x 0.8 < tc2 < tc1 x 1.2 is satisfied.

6. The method for manufacturing a resin part according to claim 5, wherein tc1×0.7<tc3<tc1×1.3 is satisfied, where tc3 is a thickness of the molding material in the region of the vertical surface portion of one side A2 of the resin part.

7. A method for manufacturing a structure having the resin part obtained by the manufacturing method according to any one of claims 2 to 6 and a metal part, comprising: A method for manufacturing a structure, wherein at least a portion of the metal part is arranged on the outer surface of the resin part along the top surface or the bottom surface.

8. The metal part has a deflection portion extending on the outer surface, the deflection portion being changed in direction; The method for manufacturing a structure according to claim 7 , wherein the resin part and the metal part are fixed to each other at the direction-changing portion.

9. The method for manufacturing a structure according to claim 7 or 8, wherein at least a portion of the metal component is disposed along the top surface portion.

10. the metal component has a first portion extending in a first in-plane direction and a second portion extending in a second in-plane direction different from the first in-plane direction; The deflection portion connects the first portion and the second portion. A method for manufacturing the structure according to any one of claims 7 to 9.

11. The method for manufacturing a structure according to claim 10 , wherein the first in-plane direction and the second in-plane direction are perpendicular to each other.

12. The method for manufacturing a structure according to claim 7 , wherein a relationship between the height difference h between the top surface portion and the bottom surface portion and a flatness Fa of the resin part satisfies 0<Fa / h<1.

3.

13. The method for manufacturing a battery tray or a protective cover for a battery tray according to any one of claims 7 to 11, wherein the metal part is an electrical circuit for impact detection, and the structure is a battery tray or a protective cover for a battery tray.

14. The method for manufacturing an inverter box according to any one of claims 7 to 11, wherein the metal part is an electric circuit and the structure is an inverter box.

15. The method for manufacturing a wireless power supply box according to claim 7 , wherein the structure is a wireless power supply box.

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