Manufacturing method for molded products

Abstract

The present invention prevents an end of the composite material from being caught by an injection molding material when the composite material and the injection molding material are integrally molded. Provided is a manufacturing method for a molded article which is integrally molded with a composite material containing reinforcing fibers dispersed in an in-plane direction and a resin, and an injection molding material, by using a first mold and a second mold, the manufacturing method comprising the following steps 101 to 401: the step 101 of placing the composite material in a cavity of the first mold; the step 201 of moving the second mold toward the placed composite material; the step 301 of injecting the injection molding material from a first gate and a second gate provided in the first mold into the mold; and the step 401 of pressing the composite material and the injection molding material in the mold to integrally form the molded article. Note that: (a) in the step 101, the cavity area of the first mold is larger than the area of the placed composite material; (b) the position of the first gate is in a region where the sheet-like composite material is placed in the step 301, and the position of the second gate is in a region where the sheet-like composite material is not placed in the step 301; and (c) the injection molding material does not enter a gap between the composite material and the second mold when the molding is completed.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a molded article, in which a sheet-like composite material and an injection molding material with higher fluidity than the sheet-like composite material are integrally molded. [Background technology]

[0002] Composite materials using reinforcing fibers such as carbon fiber and glass fiber as reinforcing materials have high tensile strength and tensile modulus, and excellent dimensional stability due to their low coefficient of linear expansion. Furthermore, they also have excellent heat resistance, chemical resistance, fatigue resistance, abrasion resistance, electromagnetic shielding properties, and X-ray transparency. For these reasons, composite materials are widely applied in automotive, sports and leisure, aerospace, and general industrial applications.

[0003] Incidentally, methods for integrally manufacturing molded articles from multiple different materials are being considered. For example, Patent Document 1 discloses a mold device in which the peripheral edge of the surface material is pressed into and clamped in a pin receiving hole, while a pin is fitted into the pin receiving hole, and the surface material is pressed and held between the pressing surface of the surface material pressing frame and the surface material mounting surface of the lower mold. After supplying molten thermoplastic resin between the surface material held in the lower mold and the molding surface of the upper mold, when clamping is started, the molten thermoplastic resin flows, and the surface material is pressed by the clamping, stretched to conform to the mold shape and squeezed into the inside of the mold. At the same time, the peripheral edge of the surface material slides between the pin and the pin receiving hole and between the pressing surface and the surface material mounting surface, and is drawn inward into the mold.

[0004] Patent Document 2 discloses a mold for press-molding a sheet material in which a discontinuous fiber-reinforced thermoplastic resin layer is laminated on at least a portion of one side of a continuous fiber-reinforced thermoplastic resin layer, to produce a fiber-reinforced thermoplastic resin molded product. The mold is provided in which a frame-shaped weir is located on the outer edge of the cavity, which prevents the discontinuous fiber-reinforced thermoplastic resin layer from flowing out of the cavity when the upper and lower molds are closed, while forming a gap that allows the continuous fiber-reinforced thermoplastic resin layer to extend out of the cavity.

[0005] Patent Document 3 discloses that an auxiliary mold is placed in close contact with the outer peripheral wall of the lower mold of a stamping mold and is capable of sliding up and down, and when the molten thermoplastic resin between the upper and lower molds of the stamping mold is press-molded to form a base material and a surface material is pressed onto the base material, the auxiliary mold prevents the molten material from leaking out from between the upper and lower molds.

[0006] Patent Document 4 provides a manufacturing method for producing injection-molded products containing multiple sheets at a lower cost. The specific procedure is described as follows: First, the gate nozzle is extended and resin is injected and bonded between the outer sheet and the adjacent reinforcing resin-impregnated sheet. Next, the movable mold is moved to the opposite side from the fixed mold, and the outer sheet and the reinforcing resin-impregnated sheet are moved together with the movable mold. After that, the reinforcing resin-impregnated sheet bonded to the outer sheet is bonded to the reinforcing resin-impregnated sheet located next to it. Finally, the moving step and the bonding step are repeated a number of times equal to the number of reinforcing resin-impregnated sheets minus 1.

[0007] Patent Document 5 describes a molding method in which injection molding material is flowed from a region other than the vertical surface to the vertical surface. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent No. 3413356 [Patent Document 2] Japanese Patent No. 5855401 [Patent Document 3] Japanese Patent Publication No. 9-117922 [Patent Document 4] Japanese Patent Publication No. 2020-179549 [Patent Document 5] WO2020 / 196076 issue [Overview of the project] [Problems that the invention aims to solve]

[0009] However, when integrally molding multiple materials with different fluidity levels within a mold, there is a risk that the ends of the material with low fluidity (sheet-like composite material) may become lodged between the injection-molded materials with high fluidity.

[0010] A further challenge of the present invention is that if the filling speed of the injection molding material in the mold is too fast, problems such as (i) disruption of the orientation of the low-flowability sheet-like composite material, (ii) wrinkling, and (iii) stretching or tearing occur. Conversely, if the filling speed is too slow, the injection molding material does not spread sufficiently in the mold, resulting in poor filling of the injection molding material and a poor appearance.

[0011] In this regard, the method described in Patent Document 1 fixes the surface material by holding it at the outer circumference of the mold. However, the method described in Patent Document 1 cannot be applied when injection molding a material with low fluidity completely from inside the mold cavity, such as in insert molding.

[0012] Although the method described in Patent Document 2 includes a weir at the outer edge of the cavity to prevent the outflow of the discontinuous fiber-reinforced thermoplastic resin layer, it does not consider the case where a low-flowability sheet-like composite material is completely placed inside the mold cavity.

[0013] In the method described in Patent Document 3, the surface material is held outside the mold by a jig. However, the method described in Patent Document 3 cannot be applied to molding in cases where low-flowability materials are completely placed inside the mold cavity, such as in insert molding.

[0014] In the method of Patent Document 4, as the reinforcing member resin-impregnated sheet, a plain weave cloth made of glass fibers with a wire diameter of about 17 μm impregnated with a polypropylene resin is used. When a material in which reinforcing fibers are continuous and oriented in a specific direction, such as a plain weave cloth, is used, if there is even a slight deviation (even if a deviation of several millimeters occurs) in the arrangement when the injection material is introduced and press-molded, it becomes difficult to obtain the desired physical properties. Therefore, measures such as devising the mold so that the reinforcing member resin-impregnated sheet does not deviate are required. In particular, when trying to impregnate resin between multiple reinforcing members, the process becomes overly complicated.

[0015] In the method of Patent Document 5, in the filling of the injection molding material, the consideration when two or more gate positions are provided is not sufficient.

[0016] An object of the present invention is to provide a method for manufacturing a molded body when integrally molding a sheet-like composite material and an injection molding material, without fixing the sheet-like composite material at the outer peripheral portion of the cavity of the mold.

Means for Solving the Problems

[0017] In order to solve the above problems, the present invention provides the following means. 1. A method for manufacturing a molded body integrally formed by a sheet-like composite material containing reinforcing fibers dispersed in the in-plane direction and a resin, and an injection molding material, using a first mold and a second mold, the method for manufacturing a molded body including the following steps 101 to 401: Step 101: A step of disposing the sheet-like composite material in the cavity of the first mold; Step 201: A step of moving the second mold toward the disposed sheet-like composite material; Step 301: A step of injecting the injection molding material into the mold from a first gate and a second gate provided in the first mold; Step 401: A step of pressing the sheet-like composite material and the injection molding material in the mold to integrally mold the molded body, However, (a) In step 101, the cavity area of ​​the first mold is larger than the area of ​​the sheet-like composite material that is placed there. (b) The position of the first gate is in the region where the sheet-like composite material is placed in step 301, and the position of the second gate is in the region where the sheet-like composite material is not placed in step 301. (c) When molding is complete, no injection molding material enters between the sheet-like composite material and the second mold. 2. A method for manufacturing a molded article as described in item 1 above, A method for manufacturing a molded article, wherein the flow time of the first injection molding material injected from the first gate is 5 seconds or less, and the maximum flow velocity is 200 mm / sec or less. 3. A method for manufacturing a molded article according to either item 1 or 2, wherein the weld line formed by the first injection-molded material injected from the first gate and the second injection-molded material injected from the second gate is generated outside the area where the sheet-like composite material is placed after the completion of molding. 4. In the manufactured molded body, the portion formed by the sheet-like composite material is a reinforcing portion. The portion formed by the injection-molded material that is in a laminated relationship with the reinforcing portion is called the laminated injection portion, and the portion formed by the injection-molded material other than the laminated injection portion is called the main body portion. In step 301, let V1 be the amount of first injection molding material injected from the first gate, V2 be the amount of second injection molding material injected from the second gate, X1 be the distance from the first gate to the end of the sheet-like composite material, and X2 be the distance from the second gate to the end of the sheet-like composite material. The following conditions must be met: V1 / (X1 × volume of the layered injection molding section) > V2 / (X2 × volume of the main body section) A method for manufacturing a molded article according to any one of the above 1 to 3. 5. When the first gate and the second gate are connected by a straight line, and the point P is defined as the point where this straight line intersects with the end of the sheet-like composite material, X1 is the distance between position P and the first gate. X2 is the distance between position P and the second gate. The method for manufacturing a molded article as described in item 4 above. 6. A method for manufacturing a molded article according to any one of items 3 to 5, wherein the first injection-molded material reaches the end of the sheet-like composite material before the second injection-molded material. 7. A method for manufacturing a molded article according to any one of items 4 to 6 above, wherein X1 is 10 mm or more and 1000 mm or less, X2 is 20 mm or more and 1200 mm or less, V1 is 25 ml or more and 1200 ml or less, and V2 is 10 ml or more and 1000 ml or less. 8. A method for manufacturing a molded article according to any one of items 1 to 7, wherein in step 301, the second mold contacts a sheet-like composite material to block the injection molding material. 9. A method for manufacturing a molded article according to any one of items 1 to 8, wherein in step 101, the sheet-like composite material is placed only in the cavity of the first mold. [Effects of the Invention]

[0018] In the molded articles produced by the manufacturing method of the present invention, since no injection molding material is inserted between the sheet-like composite material and the second mold at the completion of molding, the physical properties of the sheet-like composite material can be fully exhibited, and the appearance and design are excellent. Furthermore, it is possible to prevent the sheet-like composite material from shifting position within the mold without having to fix it outside the mold cavity. Furthermore, by using a sheet-like composite material containing reinforcing fibers dispersed in the in-plane direction, the basic mechanical properties do not change significantly even if the sheet-like composite material flows slightly during molding. In addition, shape conformability is improved compared to materials using continuous fibers such as plain weave cloth. [Brief explanation of the drawing]

[0019] [Figure 1] A schematic diagram showing the relationship between the injection gate and the sheet-like composite material in the molding process 301 of the present invention. [Figure 2] A schematic diagram showing the relationship between the injection gate and the sheet-like composite material in the molding process 301 of the present invention. [Figure 3A]In molding process 301, V1<V2かつX1> A schematic diagram showing the relationship between the injection gate and the sheet-like composite material in the case of X2. [Figure 3B] In molding process 301, V1<V2かつX1> A schematic diagram showing the relationship between the injection gate and the sheet-like composite material in the case of X2. [Figure 4] A schematic diagram showing a sheet-like composite material arranged along a first mold. [Figure 5] A schematic diagram showing the positional relationship between the injection gate and the placement area of ​​the sheet-like composite material in process 101. [Figure 6] A schematic diagram showing how the sheet-like composite material is bent along the mold in step 101. [Figure 7] A schematic diagram showing how the mold is bent from the second gate (102) to the sheet-like composite material in process 101. [Figure 8] A schematic diagram showing how the second mold contacts and holds down the sheet-like composite material. [Figure 9] A schematic diagram showing an example of a cross-section of a molded article produced by the manufacturing method of the present invention. [Figure 10] A schematic diagram showing an example of a cross-section of a molded article produced by the manufacturing method of the present invention at the completion of molding. [Modes for carrying out the invention]

[0020] Embodiments of the present invention will be described in detail below.

[0021] [Reinforcement section, laminated injection section, main body section] In a molded product, the portion formed from a sheet-like composite material is sometimes called the reinforcing portion, the portion formed from injection-molded material that is laminated to the reinforcing portion is sometimes called the laminated injection portion, and the portion formed from injection-molded material other than the laminated injection portion is sometimes called the main body portion. The main body portion is preferably larger than the reinforcing portion. For example, Figure 9 shows a cross-sectional view of the molded body in this embodiment. 901 in Figure 9 is the reinforcing portion. The portion formed by injection molding material, which is in a laminated relationship with the reinforcing portion 901, is the laminated injection portion 902. The portion formed by injection molding material other than the laminated injection portion 902 is the main body portion 903.

[0022] Preferably, the laminated injection section 902 is created by a first injection molding material 111 injected from a first gate, which will be described later. On the other hand, preferably, the main body section 903 is formed by the injection molding material 111 and a second injection molding material 112 injected from a second gate, which will be described later. The volume of the first injection molding material 111 used (injection amount V1) is preferably larger than the volume of the laminated injection section 902, and the volume of the second injection molding material 112 used (injection amount V2) is preferably smaller than the volume of the main body section 903. When the volume of the first injection molding material 111 is larger than the volume of the laminated injection section 902, and the volume of the second injection molding material 112 is smaller than the volume of the main body section 903, as shown in Figure 9, a weld line 904 at the boundary between the first injection molding material 111 and the second injection molding material 112 is formed at a position away from the reinforcing section 901 of the main body section 903.

[0023] [Sheet-like composite material] The sheet-like composite material contains reinforcing fibers and resin, and within the sheet-like composite material, the reinforcing fibers are dispersed in the in-plane direction within the resin. Although the composite material in this embodiment is in sheet form, the term "sheet-like composite material" may be abbreviated to simply "composite material."

[0024] [Reinforced fiber] The reinforcing fiber is preferably at least one selected from the group consisting of carbon fiber, aramid fiber, and glass fiber, and more preferably carbon fiber or glass fiber.

[0025] [Carbon fiber] 1. Carbon Fibers in General Commonly known carbon fibers include polyacrylonitrile (PAN) carbon fibers, petroleum / coal pitch carbon fibers, rayon carbon fibers, cellulose carbon fibers, lignin carbon fibers, and phenolic carbon fibers. In this embodiment, any of these carbon fibers can be suitably used. Among these, polyacrylonitrile (PAN) carbon fibers are preferred in this embodiment due to their excellent tensile strength. As a PAN carbon fiber, for example, Teijin Limited's carbon fiber "Tenax" (registered trademark) STS40-24KS (average fiber diameter 7 μm) can be used.

[0026] 2. Carbon fiber sizing agent Carbon fibers may have a sizing agent attached to their surface. When using carbon fibers with a sizing agent attached, the type of sizing agent can be appropriately selected according to the type of carbon fiber and the type of resin used in the composite material, and is not particularly limited.

[0027] [Glass fiber] 1. Glass Fibers in General Any glass fiber that is generally referred to as glass fiber is acceptable. The glass composition is not particularly limited to A glass, C glass, E glass, etc. as specified in JIS R3140:2006, and may contain components such as TiO2, SO3, P2O5, etc., depending on the case. As a glass fiber, for example, Nitto Boseki's glass fiber E-glass RS240QR-483 (count: 2400g / 1000m) can be used.

[0028] 2. Glass fiber sizing agent Glass fibers may have a sizing agent attached to their surface. When using glass fibers with a sizing agent attached, the type of sizing agent can be appropriately selected according to the type of glass fiber and the type of resin, and is not particularly limited. Glass fibers that have been pre-treated with conventionally known coupling agents such as organosilane compounds, organotitanium compounds, organoborane compounds, and epoxy compounds can preferably be used.

[0029] [Disperses in the in-plane direction] It is preferable that the reinforcing fibers contained in the sheet-like composite material are dispersed in the in-plane direction. Dispersion of reinforcing fibers in the in-plane direction means that the fiber axes of the reinforcing fibers are dispersed so as to be oriented in the in-plane direction. It is preferable that the angle that the fiber axes of the reinforcing fibers make with the in-plane direction is 45° or less. 1. In-plane direction The sheet-like composite material is preferably a plate-like material. The in-plane direction is any direction perpendicular to the thickness direction of the composite material. In the in-plane direction, "plane" refers to a "plane" perpendicular to the thickness direction of the composite material.

[0030] 2. Random distribution in 2.2 dimensions It is preferable that the reinforcing fibers are randomly dispersed in a two-dimensional direction in the in-plane direction of the sheet-like composite material. When the composite material is press-molded without flowing, the shape of the reinforcing fibers is almost maintained before and after molding, so it is also preferable that the reinforcing fibers contained in the reinforced part after molding the composite material are similarly randomly dispersed in a two-dimensional direction in the in-plane direction.

[0031] Here, "randomly dispersed in two dimensions" means that the reinforcing fibers are oriented in a disordered manner within the in-plane direction of the composite material, rather than in a specific direction such as one direction, and are arranged within the sheet surface without exhibiting a particular directionality overall. A composite material obtained using these two-dimensionally randomly dispersed discontinuous fibers is substantially isotropic, without anisotropy within the plane.

[0032] The degree of orientation, which represents the extent to which reinforcing fibers are randomly dispersed in two dimensions in the in-plane direction of the composite material, is evaluated by determining the ratio of the tensile moduli in two mutually orthogonal directions of the composite material. If the ratio (Eδ) obtained by dividing the larger of the measured tensile moduli in any direction of the composite material and in a direction perpendicular to it by the smaller is 5 or less, more preferably 2 or less, and even more preferably 1.5 or less, then the reinforcing fibers can be evaluated as being randomly dispersed in two dimensions. When the reinforced part formed by the composite material is a curved surface, a method for evaluating the extent to which the reinforcing fibers are randomly dispersed in two dimensions in the in-plane direction of the reinforced part (degree of orientation) is to heat the reinforced part above its softening temperature to return it to a flat plate shape, then remove only the reinforced part and solidify it. After that, a test piece is cut from the reinforced part that has been returned to a flat plate shape, and the tensile moduli in two mutually orthogonal directions of the test piece can be determined to evaluate the two-dimensional random dispersion in the reinforced part.

[0033] 3. Advantages of dispersing in the in-plane direction By using a composite material containing reinforcing fibers dispersed in the in-plane direction, the basic mechanical properties do not change significantly even if the composite material flows slightly during molding or if there is a displacement in its position. Furthermore, shape conformability is improved compared to materials using continuous fibers such as plain weave cloth.

[0034] [Fiber length of reinforcing fibers contained in sheet-like composite materials] The weight-average fiber length LwA of the reinforcing fibers contained in the composite material is preferably 1 mm or more, and more preferably 3 mm or more. If LwA is 100 mm or less, the fluidity of the material is less likely to decrease when the composite material is manufactured by press molding, and it is easier to create the reinforced part in the desired shape. Also, if LwA is 1 mm or more, the mechanical strength of the resulting reinforced part is less likely to decrease, which is preferable.

[0035] Since the weight average fiber length LwA of the reinforcing fibers contained in the composite material does not change before and after molding, if the weight average fiber length of the reinforcing fibers contained in the reinforcing portion is examined, the weight average fiber length LwA of the reinforcing fibers contained in the composite material can be known. The weight average fiber length LwA of the reinforcing fibers contained in the composite material is preferably 3 mm or more and 100 mm or less, more preferably 3 mm or more and 80 mm or less, and still more preferably 5 mm or more and 60 mm or less. The weight average fiber length of the reinforcing fibers is obtained by the following formula (1).

[0036] [Injection molding material] The injection molding material (the first injection molding material 111 and the second injection molding material 112) for forming the main body portion 903 and the laminated injection portion 902 preferably contains a resin and reinforcing fibers. The reinforcing fibers contained in the injection molding material are preferably the above-mentioned carbon fibers or glass fibers. The injection molding material has higher fluidity than the composite material.

[0037] [Fiber length of reinforcing fibers contained in injection molding material] Generally, the weight average fiber length of the reinforcing fibers contained in the injection molding material is shorter than the weight average fiber length of the reinforcing fibers contained in the sheet-shaped composite material. Therefore, the injection molding material preferably contains reinforcing fibers with a weight average fiber length LwB, where LwB < LwA. When LwB < LwA, the mechanical strength of the reinforcing portion formed by the composite material is higher than the mechanical strength of the main body portion (and the laminated injection portion) formed by the injection molding material, so the molded body can be reinforced by the reinforcing portion.

[0038] The injection molding material is injected into the mold to form the main body portion (and the laminated injection portion). In the production of the injection molding material, there is a kneading process. In this embodiment, the material after kneading is called the injection molding material.

[0039] The weight-average fiber length LwB of the reinforcing fibers contained in the injection-molded material is preferably less than 3 mm. More preferably, the weight-average fiber length LwB is 0.01 mm or more and less than 3 mm. The lower limit of the weight-average fiber length LwB is preferably 0.01 mm or more, more preferably 0.05 mm or more, and even more preferably 0.1 mm or more. When the weight-average fiber length LwB is 0.01 mm or more, the mechanical strength of the main body (and laminated injection part) is ensured. On the other hand, the upper limit of the weight-average fiber length LwB is preferably less than 3 mm, more preferably less than 2 mm, and even more preferably less than 1 mm. The weight-average fiber length of the reinforcing fibers can be determined by formula (1) described below.

[0040] [Weight-average fiber length Lw] Generally, the fiber length of each reinforcing fiber is L i Therefore, the weight-average fiber length Lw can be calculated using the following formula (1). Note that the unit of the weight-average fiber length Lw is mm.

[0041]

number

[0042] Reinforcement fibers can be extracted from the reinforcement section 901 and the main body section 903 (and the laminated injection section 902) by, for example, applying a heat treatment at 500°C for about 1 hour and removing the resin in the furnace. The weight-average fiber length Lw can be determined, for example, by measuring the fiber lengths L1 to L100 of 100 fibers (I=100) randomly extracted from the reinforcement section 901 and the main body section 903 (and the laminated injection section 902) after the above heat treatment to the nearest 1 mm using a caliper or the like, and calculating it based on formula (1).

[0043] If short reinforcing fibers that cannot be measured with calipers are present, after removing the resin, the obtained reinforcing fibers should be placed in water containing a surfactant, thoroughly stirred with ultrasonic vibration, and a random sample of the stirred reinforcing fiber dispersion should be taken using a measuring spoon to obtain an evaluation sample. The length of 3000 reinforcing fibers (I=3000) should then be measured using a Nireco Luzex AP image analysis system. The weight-average fiber length Lw can be determined using the measured fiber lengths L1 to L3000 in the same manner as in equation (1) described above.

[0044] [Volume ratio of reinforcing fibers in sheet-like composite materials and injection-molded materials] For both composite materials and injection-molded materials, the volume percentage (Vf) of reinforcing fibers can be determined using the following formula (2). Volume ratio of reinforcing fibers (Vf) = 100 × Volume of reinforcing fibers / (Volume of reinforcing fibers + Volume of resin) Equation (2)

[0045] There are no particular limitations on the volume percentage of reinforcing fibers contained in the composite material, but the volume percentage of reinforcing fibers (Vfa) contained in the composite material is preferably 10 Vol% or more and 60 Vol% or less, more preferably 20 Vol% or more and 50 Vol% or less, and even more preferably 25 Vol% or more and 45 Vol% or less.

[0046] Furthermore, generally speaking, injection molding materials, which have higher fluidity than composite materials, often have a lower fiber volume percentage (Vfb) of injection molding material than fiber volume percentage (Vfa) of composite material, with Vfa > Vfb. The volume percentage Vfb of reinforcing fibers contained in the injection molding material is preferably 1 Vol% or more and 40 Vol% or less, more preferably 5 Vol% or more and 30 Vol% or less, and even more preferably 10 Vol% or more and 25 Vol%.

[0047] [Analysis of the volume percentage (Vf) of reinforcing fibers] While there are no limitations to the analysis of the reinforcing fiber volume ratio, it is recommended to measure it as follows: Cut a sample from the reinforced section or main body (and laminated injection section), burn off the resin in a furnace at 500°C for 1 hour, and weigh the sample before and after treatment to calculate the mass of the reinforcing fiber and resin. Next, use the specific gravity of each component to calculate the volume ratio of the reinforcing fiber to the resin: Vf = 100 × reinforcing fiber volume / (reinforcing fiber volume + resin volume)

[0048] [resin] The resin contained in the composite material and the resin contained in the injection molded material may be thermosetting or thermoplastic. 1.Thermoplastic resin 1.1 Overview When a thermoplastic resin is used, the type is not particularly limited, and one with the desired softening point or melting point can be appropriately selected and used. Typically, thermoplastic resins with a softening point in the range of 180°C to 350°C are used, but are not limited to this range.

[0049] 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, polyetherketone resins, thermoplastic urethane resins, fluoropolymer resins, and thermoplastic polybenzimidazole resins.

[0050] The thermoplastic resin used in sheet-like composite materials and injection-molded materials may be of one type or two or more types. Examples of using two or more thermoplastic resins in combination include, but are not limited to, using thermoplastic resins with different softening points or melting points, or using thermoplastic resins with different average molecular weights.

[0051] When using thermoplastic resins, it is more preferable to use polyolefin resins, and even more preferable to use polypropylene resins.

[0052] 1.2 Resins for sheet-like composite materials and injection-molded materials The resin included in the composite material is preferably a thermoplastic resin. If the resin included in the composite material is a thermoplastic resin, it is more preferable that the resins included in the composite material and the injection-molded material are of the same type of thermoplastic resin.

[0053] 2. Thermosetting resin The resin included in the composite material may be a thermosetting resin. In this case, the composite material may be a sheet molding compound using reinforcing fibers. Due to its high moldability, sheet molding compounds can be easily molded even into complex shapes. Sheet molding compounds have higher fluidity and formability compared to continuous fibers, making it easy to create ribs and bosses.

[0054] [Other agents] Resins used in composite materials and injection-molded materials may contain additives such as various fibrous or non-fibrous fillers of organic or inorganic fibers, flame retardants, UV resistant agents, stabilizers, mold release agents, pigments, softeners, plasticizers, and surfactants, to the extent that they do not impair the objectives of the present invention.

[0055] [Preferred fiber combinations] Preferably, the reinforcing fibers in the composite material are glass fibers and / or carbon fibers, and the reinforcing fibers in the injection-molded material are glass fibers. The reinforcing fibers in the composite material may be partially carbon fibers, and glass fibers may be used in the parts other than those containing carbon fibers. The area where carbon fibers are used in the composite material is preferably, for example, the area surrounding a hole h in the molded body.

[0056] [One-piece molding] The manufacturing method for the molded body of this embodiment involves integrally molding a composite material and an injection molding material. Integral molding means that these are molded continuously without seams, and are not formed by joining separate components together. Such integral molding creates the structure in a single molding process, which can preferably be 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 cost of the part. In addition, the number of assembly steps is reduced, and inventory costs can be reduced due to the reduction in the number of parts.

[0057] [Manufacturing method] The method for manufacturing a molded article of this embodiment is a method for manufacturing a molded article integrally formed using a first mold and a second mold, comprising a composite material containing reinforcing fibers and resin dispersed in the in-plane direction and an injection molding material, and includes the following steps 101 to 401. Step 101: A step of placing the composite material into the cavity of the first mold. Step 201: A step of moving the second mold toward the positioned composite material. Step 301: A step of injecting the injection molding material into the mold from the first gate and the second gate provided in the first mold. Step 401: A step of integrally forming the molded body by pressing the composite material and the injection molding material in a mold. By integrally molding the composite material and the injection molding material, a molded body with excellent joint strength between the reinforcement, main body, and laminated injection-molded sections can be obtained. Furthermore, by pressing the composite material and the injection molding material, molded bodies with complex shapes, such as ribs and bosses, can be manufactured.

[0058] [In the case of cold pressing, manufacturing process: process 001] When the resin contained in the composite material and injection molding material is a thermoplastic resin, it is preferable to use cold press molding. A manufacturing method for producing a molded product by cold press molding includes, before step 101, step 001: "Step 001: A step of heating the composite material to a first predetermined temperature."

[0059] When a composite material is preheated to a first predetermined temperature, if the thermoplastic resin contained in the composite material is crystalline, the first predetermined temperature is a temperature above the melting point of the thermoplastic resin and below its decomposition temperature. If the thermoplastic resin contained in the composite material is amorphous, the first predetermined temperature is a temperature above the glass transition temperature of the thermoplastic resin and below its decomposition temperature.

[0060] In cold press molding, the temperatures of the first and second molds are controlled to a second predetermined temperature. If the thermoplastic resin contained in the composite material is crystalline, the second predetermined temperature is below the melting point of the thermoplastic resin. If the thermoplastic resin contained in the composite material is amorphous, the second predetermined temperature is below the glass transition temperature of the thermoplastic resin. In this way, by adjusting the temperatures of the composite material and the first mold, cold pressing can be performed effectively.

[0061] [Manufacturing method: Process 101] Step 101 is the step of placing the composite material into the cavity of the first mold. In step 101, the area of ​​the first mold cavity is larger than the area of ​​the placed composite material. The area of ​​the composite material is the area along the mold that is observed on the mold when it is placed there. For example, Figure 4 shows the composite material 105 placed along the first mold 108. The area of ​​the composite material refers to the area of ​​the composite material 105 that can be observed from 301 (eye) in Figure 4 (the surface area of ​​the composite material), and does not include the area of ​​the part in contact with the mold 108 (the back surface area of ​​the composite material). In other words, the area of ​​the composite material refers to the area of ​​one side of the composite material, and does not refer to the total area of ​​the front and back of the composite material combined, nor is it the projected area.

[0062] It is preferable to pre-shape the composite material so that it conforms to the cavity of the first mold and then place it in the cavity of the first mold. The pre-shaping does not need to conform perfectly to the first mold.

[0063] The area of ​​the composite material arranged in this embodiment is smaller than the area of ​​the first mold cavity. Therefore, there is a region in the first mold cavity where no composite material is arranged.

[0064] It is preferable to fix the composite material within the cavity of the first mold using a plurality of fixing members. The fixing members may be, for example, slide cores that form holes in the molded body. For example, the composite material may be fixed by pre-forming holes in the composite material and inserting the fixing members into the holes in the composite material. Alternatively, the composite material may be fixed by piercing it with pin-shaped fixing members. In this case, it is not necessary to pre-form holes in the composite material.

[0065] It is preferable to place the composite material only within the cavity of the first mold. Compared to placing the composite material up to the outer edge of the cavity and fixing it at the outer edge, this eliminates the need for additional equipment and keeps the molding process simple.

[0066] [Manufacturing method: Process 201] This is the step of moving the second mold toward the composite material that has been placed. The second mold may be moved until it comes into contact with the composite material, but if the injection molding material is introduced just before the second mold comes into contact with the composite material in step 301, then step 201 is completed up to the point where the injection molding material is introduced.

[0067] [Manufacturing method: Process 301] 1. Heating the injection molding material When the injection molding material is introduced into the mold, it is preferable that the material is heated to a temperature above the melting point or below the decomposition temperature of the thermoplastic resin if the thermoplastic resin is crystalline, or to a temperature above the glass transition temperature or below the decomposition temperature of the thermoplastic resin if the thermoplastic resin is amorphous. The heating is preferably performed during the kneading process.

[0068] 2. Timing of injection molding material injection The injection molding material is introduced into the mold in step 301. The timing of the injection molding material injection may be immediately before or immediately after pressure begins to be applied to a portion of the composite material from the second mold. From the viewpoint of suppressing displacement of the composite material within the mold, it is preferable to inject the injection molding material immediately after the second mold comes into contact with at least a portion of the composite material and pressure begins to be applied to the composite material. In order to fill the space between the first mold and the composite material with injection molding material, the movement of the second mold may be stopped once before the mold is completely closed. The position where the movement of the second mold is stopped is preferably after the second mold has come into contact with the composite material.

[0069] 3. Gate location 3.1 A gate for injecting the injection molding material is provided in the first mold. More preferably, the gate for injecting the injection molding material is provided in a fixed mold rather than a movable mold, and it is even more preferable that the first mold is a fixed mold. For example, in Figures 1 and 2, gates (101, 102, 103) are provided on the first mold (108) for injecting the first injection molding material 111 and the second injection molding material 112.

[0070] 3.2 Gate 1 The first gate is located in the region where the composite material 105 is to be placed. Figure 5 shows the state immediately after the composite material 105 is placed in the first mold 108. In Figure 5, the region where the composite material 105 is in contact with the first mold 108 is the region where the composite material 105 is to be placed. The first gate (101, 103), which is the injection gate, is pre-installed in this region.

[0071] 3.3 Gate 2 The second gate 102 is located in the cavity region of the first mold 108 where the composite material 105 is not placed. For example, in Figure 5, the second gate 102 is located in a position where the composite material 105 is not in contact with the cavity of the first mold 108. The position of the second gate 102 is predetermined by working backward from the position where the composite material 105 is placed.

[0072] 3.4 Injection volume and installation locations of the first and second gates In this embodiment, as shown in Figures 1 and 2, the injection amount of the first injection molding material 111 from the first gate 101 is V1, the injection amount of the second injection molding material 112 from the second gate 102 is V2, the distance from the first gate to the end of the composite material is X1, and the distance from the second gate to the end of the composite material is X2. As shown in Figure 5, if there are multiple first gates 101 and 103, the distance from the first gate 101 closest to the end of the composite material 105 to the end of the composite material 105 is defined as X1. Similarly, if there are multiple second gates, the distance from the second gate 102 closest to the end of the composite material to the end of the composite material 105 is defined as X2.

[0073] 3.4.1 X1 and X2 Figure 5 shows examples of X1 and X2 in this embodiment. X1 is the distance from the first gate (101) to the end P of the composite material (105). More specifically, when viewing the composite material 105, the first gate (the first gate 101 closest to the end of the composite material 105), and the second gate (the second gate 102 closest to the end of the composite material 105) in plan view, and drawing a straight line connecting the first gate 101 and the second gate 102, X1 is the distance between the position P where this straight line intersects with the end of the composite material 105 and the first gate 101. If the arrangement of the composite material 105 is bent along the first mold 108 as shown in Figure 6, then X1 is the distance between position P and the first gate 101 when measured using the creepage distance of the cavity surface of the first mold 108. If the distance X1 is relatively short, the first injection-molded material 111 injected from the first gate 101 can quickly spread outward beyond the end of the composite material 105.

[0074] On the other hand, X2 is the distance from the second gate (102) to the composite material (105). More specifically, when viewing the composite material 105, the first gate 101, and the second gate 102 in plan view, and drawing a straight line connecting the first gate 101 and the second gate 102, X2 is the distance between the position P where this line intersects with the end of the composite material 105 and the second gate 102. If the cavity surface of the first mold 108 is bent as shown in Figure 7, then X2 is the distance between position P and the second gate 102 when measured using the creepage distance of the cavity surface of the first mold 108. By ensuring a certain distance of X2, the second injection-molded material 112 injected from the second gate 102 can remain outside the end of the composite material 105.

[0075] 3.4.2 V1 and V2 V1 is the amount of first injection molding material 111 injected from first gates 101 and 103 located within the region where the composite material 105 is placed, in a plan view of the cavity of the mold. V2 is the amount of second injection molding material 112 injected from a second gate 102 located in a region other than the region where the composite material is placed, in a plan view of the cavity of the mold.

[0076] When the injection volume V1 of the first injection molding material 111 injected from the first gates 101 and 103 is large, the first injection molding material 111 from the first gates 101 and 103 spreads quickly into the mold cavity. Conversely, when the injection volume V1 is small, the speed at which the first injection molding material 111 spreads into the mold cavity slows down. When the injection volume V1 is small, for example, as shown by reference numeral 205 in Figure 3B, the end of the composite material 105 is more likely to become embedded between the first injection molding material 111 and the second injection molding material 112.

[0077] If the amount of the second injection molding material 112 ejected from the second gate 102, i.e., the injection amount V2, is small, the second injection molding material 112 ejected from the second gate 102 will spread slowly into the mold cavity. Conversely, if the injection amount V2 is large, the speed at which the second injection molding material 112 spreads into the mold cavity will increase. When the injection amount V2 is large, for example, as shown by reference numeral 205 in FIG. 3B, the possibility that the end of the composite material 105 penetrates between the first injection molding material 111 and the second injection molding material 112 increases.

[0078] 3.4.3 V1 / (X1 × volume of the laminated injection part) > V2 / (X2 × volume of the main body part) When V1 / (X1 × volume of the laminated injection part) > V2 / (X2 × volume of the main body part) is satisfied, the end of the material (composite material) with low fluidity in the mold can be preferably prevented from penetrating between the injection materials with fluidity. More preferably, V1 / X1 > ((V2 / X2) × 0.5), and still more preferably, V1 / X1 > V2 / X2.

[0079] As described above, the larger V1 is and the smaller V2 is, the more difficult it is for the composite material 105 to be sandwiched by the first injection molding material 111 and the second injection molding material 112. Similarly, the shorter X1 is and the longer X2 is, the more difficult it is for the composite material 105 to be sandwiched by the first injection molding material 111 and the second injection molding material 112. For example, in the case of FIG. 3A, the injection amount V1 of the first injection molding material 111 ejected from the first gates 201 and 203 is less than the injection amount V2 of the second injection molding material 112 ejected from the second gate 202, and the distance X1 from the first gate 201 to the end P of the composite material 105 is longer than the distance X2 from the second gate 202 to the end P of the composite material 105. In such a case, it is likely that V1 / X1 < V2 / X2, and as shown by reference numeral 205 in FIG. 3B, the end of the composite material 105 may be penetrated by the injection molding materials 111 and 112.

[0080] In addition to these factors, the larger the volume of the main body 903 is compared to the laminated injection molding section 902, the less likely the composite material 105 is to be sandwiched between the first injection molding material 111 and the second injection molding material 112. Generally, injection molding materials flow in the direction of the large cavity space and the smallest shear force generated during flow. The space between the composite material 105 and the second mold 107 is narrow, and a relatively high shear force is required when the second injection molding material 112 enters this space. On the other hand, if the volume of the main body 903 is large, the second injection molding material 112 will begin filling first to fill the large cavity space that forms the main body 903. Because the shear force generated during flow is relatively low in the large cavity space, the main body 903 is formed before the injection molding material 2 enters between the composite material and the second mold. Therefore, even if V2 is large or X2 is short, entry between the composite material 105 and the second mold 107 is suppressed.

[0081] Furthermore, even if the size of the laminated injection molding section 902 is small, or if V1 is small or X1 is long, the filling by the first injection molding material 111 is completed relatively quickly. In this case, the laminated injection molding section 902 is formed by the first injection molding material 111 before the main body section 903 is formed by the second injection molding material 112. At this time, the first injection molding material 111 can easily reach the edge of the composite material 105 before the second injection molding material 112.

[0082] In other words, by satisfying V1 / (X1 × volume of the laminated injection part) > V2 / (X2 × volume of the main body part), the position of the weld line 109 formed by the first injection molding material 111 injected from the first gates 101 and 103 and the second injection molding material 112 injected from the second gate 102 is formed outside the region where the composite material 105 is arranged, so that the end of the composite material 105 can be prevented from being bitten into by the injection molding materials 111 and 112 (for example, reference numeral 205 in FIG. 3B). In the manufacturing method of the preferred embodiment, the weld line 109 formed by the injection molding material 1 injected from the first gates 101 and 103 and the injection molding material 2 injected from the second gate 102 occurs outside the region where the composite material is arranged after the molding is completed. At this time, the flow length of the first injection molding material 111 becomes longer than X1 (for example, FIG. 2). Since the composite material 105 may move during molding, the location where the composite material 105 is arranged in step 101 and the region where the composite material 105 is arranged after the molding is completed do not necessarily coincide. In addition, since the composite material 105 may be referred to as the reinforcing part 901 after molding, the region where the composite material 105 is arranged after the molding is completed can be referred to as the region where the reinforcing part 901 is arranged after the molding is completed.

[0083] On the contrary, when V1 / (X1 × volume of the laminated injection part) < V2 / (X2 × volume of the main body part), as shown by reference numeral 205 in FIG. 3B, the end of the composite material 105 bites into between the first injection molding material 111 and the second injection molding material 112. In this embodiment, it is not necessarily required to fix the composite material 105 at the outer peripheral part of the cavity of the mold. This is because by satisfying V1 / (X1 × volume of the laminated injection part) > V2 / (X2 × volume of the main body part), it is possible to prevent the position of the composite material in the mold from shifting significantly.

[0084] 3.4.4 Preferred range X1 is preferably 10 mm or more and 1000 mm or less, more preferably 30 mm or more and 800 mm or less, still more preferably 50 mm or more and 600 mm or less, and even more preferably 80 mm or more and 300 mm or less.

[0085] X2 is preferably 20 mm or more and 1200 mm or less, more preferably 50 mm or more and 1000 mm or less, still more preferably 80 mm or more and 800 mm or less, and even more preferably 100 mm or more and 500 mm or less.

[0086] V1 is preferably 25 ml or more and 1200 ml or less, more preferably 50 ml or more and 1000 ml or less, still more preferably 100 ml or more and 800 ml or less.

[0087] V2 is preferably 10 ml or more and 1000 ml or less, more preferably 30 ml or more and 800 ml or less, still more preferably 80 ml or more and 600 ml or less.

[0088] The volume of the laminated injection part 902 is preferably 10 cm 3 or more and 1100 cm 3 or less, more preferably 30 cm 3 or more and 900 cm 3 or less, still more preferably 50 cm 3 or more and 700 cm 3 or less.

[0089] The volume of the main body part 903 is preferably 20 cm 3 or more and 1100 cm 3 or less, more preferably 40 cm 3 or more and 900 cm 3 or less, still more preferably 90 cm 3 or more and 700 cm 3 or less.

[0090] The volume of the reinforcing part 901 is preferably 10 cm 3 or more and 1100 cm 3 or less, more preferably 30 cm 3 or more and 900 cm 3 or less, still more preferably 50 cm 3 or more and 700 cm 3 or less.

[0091] 3.5 Generation position of the weld line A weld line is a linear pattern that appears in a molded product obtained by a molding method that melts and flows resin-based materials, where the flow of molten resin merges within the mold during molding. It is also called a weld or welded area. The name comes from the linear weld marks that appear when metal materials are welded together.

[0092] Preferably, the weld line 109 formed by the first injection-molded material 111 injected from the first gates 101 and 103 and the second injection-molded material 112 injected from the second gate 102 occurs outside the area where the composite material 105 is placed after the molding is complete.

[0093] In other words, it is preferable that the weld line 109 formed by the first injection-molded material 111 injected from the first gates 101 and 103 and the second injection-molded material 112 injected from the second gate 102 occurs outside the area where the reinforcing portion 901 is located after molding is complete. By generating the weld line 109 outside the area where the composite material 105 is located after molding is complete, it is possible to avoid the end of the composite material 105 being bitten into by the injection-molded material.

[0094] 3.6 In this embodiment, there may be multiple first gates, and similarly, there may be multiple second gates. For example, the gate labeled 103 in Figure 1 is a gate located in the region where the composite material 105 is placed, and therefore corresponds to the first gate in this embodiment.

[0095] If there are multiple first gates and multiple second gates, it is sufficient that at least one pair of first and second gates satisfy V1 / (X1 × volume of the laminated injection section) > V2 / (X2 × volume of the main body). If there are multiple first gates and multiple second gates, let V1 be the total amount of first injection molded material injected from all first gates, and V2 be the total amount of first injection molded material injected from all second gates. Then V1, V2, X1, and X2 may satisfy V1 / (X1 × volume of the laminated injection section) > V2 / (X2 × volume of the main body). Here, when a straight line is drawn connecting the first gate closest to the end of the composite material and the second gate 102 closest to the end of the composite material, and the point where this line intersects with the end of the composite material is denoted as P, the distance between the first gate closest to the end of the composite material and P is X1, and the distance between the second gate closest to the end of the composite material and P is X2.

[0096] 4. Infiltration of injection molding material In this embodiment, at the completion of molding, no injection-molded material enters between the composite material and the second mold. This results in a good appearance and design surface formed by the second mold. If the injection-molded material enters between the composite material and the second mold, the design surface of the composite material becomes invisible, resulting in an unattractive design surface. Furthermore, by preventing the injection-molded material from entering between the composite material and the second mold, the reinforced portion can fully utilize the mechanical strength of the composite material, and the physical properties of the two-dimensionally randomly dispersed reinforcing fibers contained in the reinforced portion can be realized.

[0097] Although injection molding material may enter during step 301 or step 401, in this embodiment, no injection molding material enters between the composite material and the second mold during either step 301 or step 401.

[0098] 5. Damming of injection molding material In step 301, it is preferable that the second mold contacts the composite material to block the injection molding material. For example, if the composite material 105 is held down by the upper mold 107 (second mold) as shown in Figure 8, the upper mold 107 can block the second injection molding material 112 by contacting the composite material 105. In this case, it is preferable that a relatively large cavity space in the mold extends in the direction indicated by the arrow 802 in Figure 8, as this makes it more difficult for the second injection molding material 112 to enter between the upper mold 107 and the composite material 105.

[0099] [Flow rate of injection molding material] 1. Control of flow velocity There are no particular limitations on the method of controlling the flow rate of injection molding material, but shortening the mold clamping time or the mold clamping distance during molding will increase the flow rate of the injection molding material. Furthermore, the flow rate of the injection molding material also depends on the amount of injection molding material injected.

[0100] 2. Preferred flow rate There are no particular limitations on the flow rate of the injection molding material, but it is preferable that the flow time of the first injection molding material 111 injected from the first gate is 5 seconds or less, and the maximum flow rate is 200 mm / sec or less.

[0101] If the flow time of the first injection molding material 111 is 5 seconds or less, the first injection molding material 111 can be easily filled into the cavity before the second mold 107 comes into contact with the first injection molding material 111. As a result, the first injection molding material 111 does not cool and solidify prematurely, resulting in good surface design of the resulting molded product. A more preferable flow time for the first injection molding material 111 is 4 seconds or less, and an even more preferable flow time for the first injection molding material 111 is 3 seconds or less.

[0102] On the other hand, if the maximum flow velocity of the first injection molding material 111 injected from the first gate is 200 mm / sec or less, the placed composite material 105 will not be pushed, torn, or displaced by the first injection molding material 111. In other words, when the first injection molding material 111 flows, a shear force is generated on the inner wall surface of the second mold 107 and the composite material 105, depending on the flow velocity. By setting the maximum flow velocity of the first injection molding material 111 to 200 mm / sec or less, the shear force is suppressed, and the composite material 105 can not be torn apart.

[0103] A more preferable maximum flow rate for the first injection molding material 111 is 10 mm / sec to 200 mm / sec, and an even more preferable maximum flow rate for the first injection molding material 111 is 30 mm / sec to 150 mm / sec. Preferably, the flow time of the second injection-molded material injected from the second gate is longer than the flow time of the first injection-molded material.

[0104] In general injection molding, the injection time is 2 seconds or less, preferably 1 second or less. Depending on the shape of the molded body, the injection rate (cc / sec) is often adjusted so that filling is completed within 1 second. In this embodiment, the flow velocity refers to the movement speed of the resin within the mold, not the cylinder movement speed.

[0105] [Place where injection molding material is added] It is preferable to fill the space between the first mold 108 and the composite material 105 with the injection molding material 111 injected from the first gate 101. When the injection molding material 111 is filled into the mold, the composite material 105 can be pressed against the cavity surface of the second mold 107, thereby suppressing displacement of the composite material 105. Figure 1 shows the composite material 105 being pressed against the second mold 107.

[0106] [Manufacturing method: Process 401] 1. The composite material and the injection molding material are pressed together using a first mold and a second mold to form an integral mold. The molding pressure is not particularly limited, but it is preferably less than 20 MPa, and more preferably 10 MPa or less. When the composite material and the injection molding material are pressed together in this way, the injection molding material, which has higher fluidity than the composite material, flows within the mold. Subsequently, the second mold is moved away from the first mold, and the molded body is removed from the first mold. This completes the process of creating the molded body.

[0107] [Manufacturing method: mold] In this embodiment, the first mold and the second mold are preferably a male and female pair. When using the first mold and the second mold, each may be a movable mold, or one may be a movable mold and the other a fixed mold. For example, if the first mold is a fixed mold, the second mold may be a movable mold. In some cases, a fixed mold may also move. If a fixed mold moves, the mold that moves a relatively small distance is designated as the fixed mold, and the mold that moves a relatively large distance is designated as the movable mold.

[0108] Alternatively, the first mold may be the lower mold and the second mold may be the upper mold, forming a male and female pair of upper and lower molds, in which case the second mold may open and close by moving up and down toward the first mold. Alternatively, the mold may open and close by moving at least one of the first and second molds horizontally to perform molding. [Examples]

[0109] The present invention will be described in detail below using examples, but the present invention is not limited to these examples. 1.Material 1.1 Polypropylene resin • Resin for composite materials: Novatec PP BC03C manufactured by Nippon Polypropylene Co., Ltd. • Fiber-reinforced resins for injection molding materials: Prime Polymer's Mostron L-4070P (Glass fiber weight percentage: 40%) 1.2 Fiberglass We prepared glass fiber E-glass RS240QR-483 manufactured by Nitto Boseki Co., Ltd., with a sizing agent applied to it. (Sometimes abbreviated as GF).

[0110] 2. Evaluation Method 2.1 Analysis of Reinforcement Fiber Volume Percentage (Vf) A molded product was cut from a region created with composite material or injection molding material, and the resin was burned off in a furnace at 500°C for 1 hour. The mass of the reinforcing fibers and resin was calculated by weighing the samples before and after treatment. Next, the volume ratio of reinforcing fibers to resin was calculated using the specific gravity of each component. Volume ratio of reinforcing fibers (Vf) = 100 × volume of reinforcing fibers / (volume of reinforcing fibers + volume of resin) Equation (2)

[0111] 2.2 Analysis of Weight-Average Fiber Length The weight-average fiber length of reinforcing fibers contained in molded products is measured after removing the resin in a furnace at 500°C for approximately 1 hour. 2.2.1 After removing the resin from the reinforced fiber molded product contained in the composite material by extracting the portion formed by the composite material, the length of 100 randomly selected glass fibers was measured to the nearest 1 mm using calipers and recorded. From the lengths of all the measured glass fibers (Li, where i = an integer from 1 to 100), the weight-average fiber length (LwA) was calculated using the aforementioned formula (1). 2.2.2 Reinforcement fibers contained in injection molding materials After removing the portion formed by injection molding material from the molded product and removing the resin, the resulting reinforcing fibers were placed in water containing a surfactant and thoroughly stirred using ultrasonic vibration. The stirred dispersion was randomly sampled using a measuring spoon to obtain evaluation samples, and the length of 3000 fibers was measured using a Nireco Luzex AP image analysis system. Using the measured fiber lengths, the weight-average fiber length Lw was calculated using the same method as in equation (1) described above.

[0112] [Example 1] (1) Preparation of composite materials As the glass fiber, we used E-glass RS240QR-483 glass fiber manufactured by Nitto Boseki Co., Ltd., cut to a fiber length of 20 mm. As the resin, we used Novatec PP BC03C polypropylene resin manufactured by Nippon Polypropylene Co., Ltd. A composite composition of glass fiber and polypropylene resin was prepared in which the glass fibers were oriented in a two-dimensional random manner according to the method described in U.S. Patent No. 10006677. The obtained composite composition was heated in a press device heated to 250°C at 2.0 MPa for 5 minutes to create a flat composite material with an average thickness of 3 mm and dimensions of 300 mm (length) x 500 mm (width). The fiber volume ratio (Vf) was 35%.

[0113] (2) Preparation of the mold Upper and lower molds were prepared, with the lower mold designated as the first mold and the upper mold as the second mold. The mold cavity was a rectangular shape (flat plate) measuring 300 mm x 806 mm, and one first gate and one second gate were installed. The design volumes of the reinforcement section, laminated injection section, and main body are shown in Table 1.

[0114] (3) Manufacturing of molded products After drying the composite material in a hot air dryer at 120°C for 4 hours, the temperature was raised to 220°C using an infrared heater, and the composite material 105 was placed in the mold lower 108 as shown in Figure 5. More specifically, the composite material 105, measuring 300 mm in length and 500 mm in width, was placed so as to align with the edge of a flat mold cavity measuring 300 mm in length and 806 mm in width.

[0115] When the first gate 201 and the second gate 202 are connected by a straight line, and the point where the ends intersect is denoted as P, the distance between position P and the first gate 201 is denoted as X1, and the distance between position P and the second gate 202 is denoted as X2. The distances of X1 and X2 were designed as shown in Table 1.

[0116] The mold temperature was set to 50°C and the mold was closed. After confirming with a pressure gauge that pressure had begun to be applied to a portion of the composite material 105, injection molding was performed using a Prime Polymers Mostron L-4070P, with injection amounts V1 and V2 of injection molding material 1 and injection molding material 2 set as shown in Table 1. The heating temperature of the injection molding material was set to 240°C.

[0117] Subsequently, the composite material 105, injection molding material 1, and injection molding material 2 were pressed simultaneously under a press pressure of 20 MPa for 1 minute to produce a molded body.

[0118] (4) Observation of the molded body We observed the pinching of the edges of the composite material and the disruption of the arrangement of the composite material due to injection molding material 1 and injection molding 2. Upon completion of molding, the reinforcing portion 1001, the main body portion 1003, and the laminated injection portion 1002 were formed, as shown in Figure 10. The weld line formed between the injection molding material 1 and the injection molding material 2 was located at 1004. The edges of the composite material 1001 were not sandwiched between the injection-molded material 1 and the injection-molded material 2. Furthermore, no irregularities in the arrangement of the composite material 1001 were observed. The results are shown in Table 1.

[0119] The volume of the main body 1003 is greater than the injection volume V2 of the injection molding material 2, indicating that it is formed by the injection molding material 1 and the injection molding material 2.

[0120] [Example 2] Except for changing the size of the composite material, the injection amounts of injection molding material 1 and injection molding material 2, and the distance of X2 as shown in Table 1, the molded body was created in the same manner as in Example 1. The edges of the composite material 1001 were not sandwiched between the injection-molded material 1 and the injection-molded material 2. Furthermore, no irregularities in the arrangement of the composite material 1001 were observed. The results are shown in Table 1.

[0121] [Example 3] Except for shortening the clamping time to increase the flow rate as shown in Table 1, the molded body was prepared in the same manner as in Example 1. The edges of the composite material 1001 were not sandwiched between the injection-molded material 1 and the injection-molded material 2. There was some disorder in the arrangement of the composite material 1001. The results are shown in Table 1.

[0122] [Comparative Example 1] Except for changing the injection volume of injection molding material 1, the injection volume of injection molding material 2, the distance of X1, and the distance of X2 as shown in Table 1, a molded body was created in the same manner as in Example 1. The results are shown in Table 1. Because the distance of X1 was longer and the distance of X2 was shorter, the edges of the composite material were sandwiched between injection molding material 1 and injection molding material 2. No disorder in the arrangement of composite material 1001 was observed. The results are shown in Table 1.

[0123] [Table 1]

Claims

1. A method for manufacturing a molded body integrally formed using a first mold and a second mold, comprising a sheet-like composite material containing reinforcing fibers and resin dispersed in the in-plane direction, and an injection molding material, comprising the following steps 101 to 401: Step 101: Step of placing the sheet-like composite material into the cavity of the first mold; Step 201: Step of moving the second mold toward the sheet-like composite material that has been placed; Step 301: The step of injecting the injection molding material into the mold from the first gate and the second gate provided in the first mold; Step 401: A step of integrally forming the molded body by pressing the sheet-like composite material and the injection molding material in a mold. however, (a) In step 101, the cavity area of ​​the first mold is larger than the area of ​​the sheet-like composite material that is placed there. (b) The position of the first gate is in the region where the sheet-like composite material is placed in step 301, and the position of the second gate is in the region where the sheet-like composite material is not placed in step 301. (c) When molding is complete, no injection molding material enters between the sheet-like composite material and the second mold. In the manufactured molded body, the portion formed by the sheet-like composite material is a reinforcing portion. The portion formed by the injection-molded material that is in a laminated relationship with the reinforcing portion is called the laminated injection portion, and the portion formed by the injection-molded material other than the laminated injection portion is called the main body portion. In step 301, when V1 is the amount of first injection molding material injected from the first gate, V2 is the amount of second injection molding material injected from the second gate, X1 is the distance from the first gate to the end of the sheet-like composite material, and X2 is the distance from the second gate to the end of the sheet-like composite material, The following conditions must be met: V1 / (X1 × volume of the layered injection molding section) > V2 / (X2 × volume of the main body section) A method for manufacturing a molded product.

2. A method for manufacturing a molded article according to claim 1, A method for manufacturing a molded article, wherein the flow time of the first injection molding material injected from the first gate is 5 seconds or less, and the maximum flow velocity is 200 mm / sec or less.

3. A method for manufacturing a molded article according to claim 1 or 2, wherein the weld line formed by the first injection-molded material injected from the first gate and the second injection-molded material injected from the second gate is generated outside the area where the sheet-like composite material is placed after the completion of molding.

4. When the first gate and the second gate are connected by a straight line, and the point P is defined as the point where this straight line intersects with the end of the sheet-like composite material, X1 is the distance between position P and the first gate. X2 is the distance between position P and the second gate. A method for manufacturing a molded article according to claim 1 or 2.

5. The method for manufacturing a molded article according to claim 3, wherein the first injection-molded material reaches the end of the sheet-like composite material before the second injection-molded material.

6. A method for manufacturing a molded article according to claim 1 or 2, wherein X1 is 10 mm or more and 1000 mm or less, X2 is 20 mm or more and 1200 mm or less, V1 is 25 ml or more and 1200 ml or less, and V2 is 10 ml or more and 1000 ml or less.

7. A method for manufacturing a molded article according to claim 1 or 2, wherein in step 301, the second mold contacts a sheet-like composite material to block the injection molding material.

8. A method for manufacturing a molded article according to claim 1 or 2, wherein in step 101, the sheet-like composite material is placed only within the cavity of the first mold.

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