Manufacturing method for molded article

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

Manufacturing method of molded body

[0001] The present invention relates to a method for producing a molded article that is integrally molded from a sheet-like composite material and an injection molding material that has higher fluidity than the sheet-like composite material.

[0002] Composite materials using reinforcing fibers such as carbon fiber and glass fiber as reinforcements have high tensile strength and tensile modulus, and a small coefficient of linear expansion, resulting in excellent dimensional stability. Furthermore, they also have excellent heat resistance, chemical resistance, fatigue resistance, abrasion resistance, electromagnetic wave shielding properties, and X-ray transparency. For these reasons, composite materials are widely used in a variety of fields, including automobiles, sports and leisure, aerospace, and general industrial applications.

[0003]

[0003] Methods for manufacturing integrally molded articles from a plurality of different materials have been studied. For example, Patent Document 1 discloses a molding device in which pins are fitted into pin receiving holes while the peripheral edge of a skin material is pressed and clamped into the pin receiving holes, and the pins are pressed and held between the pressing surface of a skin material pressing frame and the skin material mounting surface of a lower mold. After molten thermoplastic resin is supplied between the skin material held in the lower mold and the molding surface of the upper mold, clamping begins. The molten thermoplastic resin flows, and the skin material is pressed by the clamping, stretched to conform to the mold shape and squeezed into the mold interior. At the same time, the peripheral edge of the skin material slides between the pins and the pin receiving holes and between the pressing surface and the skin material mounting surface, and is drawn toward the interior of the mold.

[0004] Patent Document 2 discloses the use of a mold for producing a fiber-reinforced thermoplastic resin molded product by 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, in which a frame-shaped dam portion is provided on the outer periphery of the cavity when the upper and lower molds are closed, to prevent the discontinuous fiber-reinforced thermoplastic resin layer from flowing out of the cavity, 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 that is in close contact with the outer peripheral wall of the lower mold of a stamping mold and can slide up and down is arranged, and when a molten thermoplastic resin between the upper and lower molds of the stamping mold is press-molded to form a substrate and a skin material is pressure-bonded to the substrate, the auxiliary mold prevents the molten material from leaking from between the upper and lower molds.

[0006] The manufacturing method provided in Patent Document 4 is a method for inexpensively producing injection-molded products containing multiple sheets. The specific procedure is described as follows: First, the gate nozzle is extended, and resin is injected between the outer sheet and the adjacent reinforcing member resin-impregnated sheet to bond them together. Next, the movable mold is moved to the opposite side of the fixed mold, and the outer sheet and reinforcing member resin-impregnated sheet are moved along with the movable mold. After that, the reinforcing member resin-impregnated sheet bonded to the outer sheet is bonded to the reinforcing member resin-impregnated sheet located next to it. Finally, the moving process and adhesive sheet bonding process are repeated one time less the number of reinforcing member resin-impregnated sheets.

[0007] Patent Document 5 describes a molding method in which an injection molding material is made to flow onto the vertical surface from a region other than the vertical surface.

[0008] Japanese Patent No. 3413356 Japanese Patent No. 5855401 Japanese Patent Publication No. 9-117922 Japanese Patent Publication No. 2020-179549 Publication WO2020 / 196076

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

[0010] Another problem of the present invention is that if the injection molding material is filled into the mold too quickly, problems will arise such as (i) the orientation of the sheet-like composite material having low fluidity will be disturbed, (ii) wrinkles will occur, and (iii) the composite material will stretch or tear. Conversely, if the filling speed is too slow, the injection material will not spread enough in the mold, resulting in insufficient filling of the injection molding material and a poor appearance.

[0011] In this regard, the method of Patent Document 1 fixes the skin material by holding it on the outer periphery of the mold, but the method of Patent Document 1 cannot be applied to insert molding, or other processes in which a material with low fluidity is injection molded completely from within the mold cavity.

[0012] In the method of Patent Document 2, a dam portion is provided at the outer peripheral edge of the cavity to prevent the outflow of the discontinuous fiber reinforced thermoplastic resin layer, but no consideration is given to the case where a sheet-like composite material with low fluidity is placed completely within the cavity of the mold.

[0013] In the method of Patent Document 3, the skin material is held outside the mold by a jig, but the method of Patent Document 3 cannot be applied to molding in which a material with low fluidity is placed completely inside the mold cavity, such as insert molding.

[0014] The method of Patent Document 4 uses a reinforcing member resin-impregnated sheet made of a plain-woven cloth made of glass fibers with a wire diameter of approximately 17 μm, impregnated with polypropylene resin. When using a material in which the reinforcing fibers are continuous and oriented in a specific direction, such as a plain-woven cloth, even slight misalignment (even a few millimeters) during press molding after injection molding makes it difficult to obtain the desired physical properties. Therefore, measures such as modifying the molding die to prevent misalignment of the reinforcing member resin-impregnated sheet are necessary. In particular, when attempting to impregnate resin between multiple reinforcing members, the process becomes too complicated.

[0015] The method of Patent Document 5 does not fully consider the case where two or more gate positions are provided in filling the injection molding material.

[0016] An object of the present invention is to provide a method for producing a molded article when a sheet-like composite material and an injection molding material are integrally molded without fixing the sheet-like composite material on the outer periphery of the cavity of a mold.

[0017] In order to solve the above problems, the present invention provides the following means: 1. A method for manufacturing a molded body integrally molded using a first molding die and a second molding die from a sheet-like composite material containing reinforcing fibers and a resin dispersed in an in-plane direction and an injection molding material, the method comprising the following steps 101 to 401: step 101: placing the sheet-like composite material in a cavity of the first molding die; step 201: moving a second molding die toward the placed sheet-like composite material; step 301: injecting the injection molding material into the molding die from first and second gates provided on the first molding die; step 401: pressing the sheet-like composite material and the injection molding material in the molding die to integrally mold the molded body, with the proviso that: (a) in step 101, the cavity area of ​​the first molding die is larger than the area of ​​the placed sheet-like composite material, (b) the first gate is located in an area where the sheet-like composite material is placed in step 301, and the second gate is located in an area where the sheet-like composite material is not placed in step 301, and (c) no injection molding material gets in between the sheet-like composite material and the second mold when molding is complete. 2. A method for manufacturing a molded body as described in item 1 above, wherein the flow time of the first injection molding material injected from the first gate is 5 seconds or less and the maximum flow speed is 200 mm / sec or less. 3. A method for manufacturing a molded body as described in either item 1 or 2 above, wherein a weld line formed between the first injection molding material injected from the first gate and the second injection molding material injected from the second gate occurs outside the area where the sheet-like composite material is placed after molding is complete.4. A method for producing a molded body according to any one of paragraphs 1 to 3, wherein in the produced molded body, a portion formed by the sheet-like composite material is a reinforcing portion, a portion formed by the injection molding material in a layered relationship with the reinforcing portion is a layered injection portion, and a portion formed by the injection molding material other than the layered injection portion is a main body portion, and in step 301, when the injection amount of the first injection molding material injected from the first gate is V1, the injection amount of the second injection molding material injected from the second gate is V2, 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 relationship V1 / (X1 × volume of layered injection portion) > V2 / (X2 × volume of main body portion) is satisfied. 5. A method for producing a molded body according to paragraph 4, wherein when a straight line connects the first gate and the second gate and a position P is defined as a point where the line intersects with the end of the sheet-like composite material, X1 is the distance between position P and the first gate, and X2 is the distance between position P and the second gate. 6. 6. A method for producing a molded body according to any one of items 3 to 5, wherein the first injection molding material reaches an end of the sheet-like composite material before the second injection molding material. 7. A method for producing a molded body according to any one of items 4 to 6, 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 producing a molded body according to any one of items 1 to 7, wherein, in step 301, a second mold contacts the sheet-like composite material to block the injection molding material. 9. A method for producing a molded body 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.

[0018] The molded article produced by the manufacturing method of the present invention has excellent appearance design, as the injection molding material does not get between the sheet-like composite material and the second mold upon completion of molding. Furthermore, the sheet-like composite material does not need to be fixed outside the mold cavity, preventing the sheet-like composite material from shifting position within the mold. Furthermore, by using a sheet-like composite material containing reinforcing fibers dispersed in the in-plane direction, even if the sheet-like composite material flows slightly during molding, its basic mechanical properties do not change significantly. Furthermore, shape conformability is also improved compared to those using continuous fibers such as plain weave cloth.

[0019] 1 is a schematic diagram showing the relationship between an injection gate and a sheet-like composite material in molding process 301 of the present invention. 2 is a schematic diagram showing the relationship between an injection gate and a sheet-like composite material in molding process 301 of the present invention. 3 is a schematic diagram showing the relationship between an injection gate and a sheet-like composite material when V1<V2 and X1>X2 in molding process 301. 4 is a schematic diagram showing the relationship between an injection gate and a sheet-like composite material when V1<V2 and X1>X2 in molding process 301. 5 is a schematic diagram showing the state in which a sheet-like composite material is arranged along a first molding die. 6 is a schematic diagram showing the positional relationship between an injection gate and an arrangement area of ​​a sheet-like composite material in process 101. 7 is a schematic diagram showing the arrangement of a sheet-like composite material bent along the molding die in process 101. 8 is a schematic diagram showing the molding die bent from a second gate (102) to the sheet-like composite material in process 101. 9 is a schematic diagram showing the state in which a second molding die contacts and presses down the sheet-like composite material. 1 is a schematic diagram showing an example of a cross section of a molded body produced by the production method of the present invention, and FIG. 2 is a schematic diagram showing an example of a cross section of a molded body produced by the production method of the present invention at the time of completion of molding.

[0020] Hereinafter, embodiments of the present invention will be described in detail.

[0021] [Reinforcing portion, laminated injection portion, main body portion] In a molded body, the portion formed from a sheet-like composite material may be called the reinforcing portion, the portion formed from an injection molding material that is laminated to the reinforcing portion may be called the laminated injection portion, and the portion formed from an injection molding material other than the laminated injection portion may be 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 a molded body in this embodiment. In Figure 9, 901 is the reinforcing portion. The portion formed from an injection molding material that is laminated to the reinforcing portion 901 is the laminated injection portion 902. The portion formed from an injection molding material other than the laminated injection portion 902 is the main body portion 903.

[0022] The stacked injection portion 902 is preferably made of a first injection molding material 111 injected from a first gate (described later). Meanwhile, the main body portion 903 is preferably made of the injection molding material 111 and a second injection molding material 112 injected from a second gate (described later). The volume of the first injection molding material 111 (injection amount V1 of the injection molding material) is preferably larger than the volume of the stacked injection portion 902, and the volume of the second injection molding material 112 (injection amount V2 of the injection molding material) is preferably smaller than the volume of the main body portion 903. If the volume of the first injection molding material 111 is larger than the volume of the stacked injection portion 902 and the volume of the second injection molding material 112 is smaller than the volume of the main body portion 903, a weld line 904 at the boundary between the first injection molding material 111 and the second injection molding material 112 will be formed away from the reinforcement portion 901 of the main body portion 903, as shown in FIG. 9 .

[0023] [Sheet-shaped composite material] The sheet-shaped composite material includes reinforcing fibers and a resin, and in the sheet-shaped composite material, the reinforcing fibers are dispersed in the in-plane direction within the resin. Note that, although the composite material in this embodiment is in a sheet shape, the "sheet-shaped composite material" may be simply referred to as the "composite material" in some cases.

[0024] [Reinforcing 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 Generally, 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, and the like are known as carbon fibers. Any of these carbon fibers can be suitably used in this embodiment. Among these, polyacrylonitrile (PAN)-based carbon fibers are preferably used in this embodiment because of their excellent tensile strength. As a PAN-based carbon fiber, for example, TENAX (registered trademark) STS40-24KS carbon fiber (average fiber diameter 7 μm) manufactured by Teijin Limited can be used.

[0026] 2. Sizing Agent for Carbon Fiber The carbon fiber may have a sizing agent attached to its surface. When using carbon fiber with a sizing agent attached, the type of sizing agent can be appropriately selected depending on the type of carbon fiber and the type of resin used in the composite material, and is not particularly limited.

[0027] [Glass Fiber] 1. Glass Fiber in General The glass fiber may be any glass fiber that is generally called glass fiber. The glass composition, such as A glass, C glass, E glass, etc., as specified in JIS R3140:2006, is not particularly limited, and TiO may be used in some cases. ２ , S.O. ３ , P ２ O ５ The glass fiber may contain components such as E-glass RS240QR-483 (count: 2400 g / 1000 m) manufactured by Nitto Boseki Co., Ltd., for example.

[0028] 2. Sizing Agent for Glass Fiber The glass fiber 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.

[0029] [Dispersion in the in-plane direction] The reinforcing fibers contained in the sheet-like composite material are preferably dispersed in the in-plane direction. 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. The angle between the fiber axes of the reinforcing fibers and the in-plane direction is preferably 45° or less. 1. The in-plane direction 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. The "plane" in the in-plane direction is a "plane" perpendicular to the thickness direction of the composite material.

[0030] 2. Random Dispersion in Two Dimensions The reinforcing fibers are preferably dispersed two-dimensionally randomly 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 largely maintained before and after molding, so it is preferable that the reinforcing fibers contained in the reinforcing portion after molding the composite material are also dispersed two-dimensionally randomly in the in-plane direction.

[0031] Here, "dispersed two-dimensionally at random" refers to a state in which the reinforcing fibers are randomly oriented within the plane of the composite material, rather than in a specific direction such as one direction, and are arranged within the sheet plane without any specific directionality as a whole. A composite material obtained using discontinuous fibers dispersed in this two-dimensionally at random does not have anisotropy within the plane, and is substantially isotropic.

[0032] The degree of orientation, which represents the degree to which the reinforcing fibers are randomly dispersed in two dimensions in the in-plane direction of the composite material, is evaluated by calculating the ratio of the tensile modulus of the composite material in two mutually perpendicular directions. The reinforcing fibers can be evaluated as being randomly dispersed in two dimensions if the (Eδ) ratio, calculated by dividing the larger of the tensile modulus values ​​measured in any direction of the composite 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. When the reinforcing portion formed by the composite material has a curved surface, the degree of two-dimensional random dispersion of the reinforcing fibers in the in-plane direction of the reinforcing portion (orientation degree) can be evaluated by heating the reinforcing portion to a softening temperature or higher to return it to a flat plate shape, removing only the reinforcing portion, and then solidifying it. Then, a test piece is cut out from the reinforcing portion returned to a flat plate shape, and the tensile modulus of the test piece in two mutually perpendicular directions can be measured to evaluate the two-dimensional random dispersion in the reinforcing portion.

[0033] 3. Advantages of in-plane dispersion By using a composite material containing reinforcing fibers dispersed in the in-plane direction, even if the composite material flows slightly during molding or there is a misalignment in the placement position, the basic mechanical properties will not change significantly. In addition, 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 material] The weight average fiber length LwA of the reinforcing fibers contained in the composite material is preferably 1 mm or more, 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 produced by press molding, and the reinforcing portion can be easily formed into a desired shape. Furthermore, if LwA is 1 mm or more, the mechanical strength of the resulting reinforcing portion 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, the weight average fiber length LwA of the reinforcing fibers contained in the composite material can be determined by examining the weight average fiber length of the reinforcing fibers contained in the reinforcing portion. 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 even more preferably 5 mm or more and 60 mm or less. The weight average fiber length of the reinforcing fibers can be calculated using the formula (1) described below.

[0036] [Injection Molding Material] The injection molding materials (first injection molding material 111 and second injection molding material 112) that form the main body portion 903 and the laminated injection portion 902 preferably contain resin and reinforcing fibers. The reinforcing fibers contained in the injection molding materials are preferably the above-mentioned carbon fibers or glass fibers. The injection molding materials have higher fluidity than composite materials.

[0037] [Fiber length of reinforcing fibers contained in injection molding material] Generally, the weight-average fiber length of reinforcing fibers contained in the injection molding material is shorter than the weight-average fiber length of reinforcing fibers contained in the sheet-like composite material. Therefore, it is preferable that the injection molding material contains reinforcing fibers with a weight-average fiber length LwB, and 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 reinforcing portion can reinforce the molded body.

[0038] The injection molding material is injected into a mold to form the main body (and the laminated injection part). The manufacturing of the injection molding material includes a kneading process. In this embodiment, the kneaded material is called the injection molding material.

[0039] The weight average fiber length LwB of the reinforcing fibers contained in the injection molding material is preferably less than 3 mm. The weight average fiber length LwB is more preferably 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 portion (and the laminated injection portion) 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 calculated using the formula (1) described below.

[0040] [Weight average fiber length Lw] Generally, the fiber length of each reinforcing fiber is L ｉ Then, the weight average fiber length Lw can be calculated by the following formula (1): The unit of the weight average fiber length Lw is mm.

[0041] Here, "I" indicates the number of reinforcing fibers measured.

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

[0043] If the mixture contains short reinforcing fibers that cannot be measured with a caliper, after removing the resin, the resulting reinforcing fibers are placed in water containing a surfactant and thoroughly stirred with ultrasonic vibrations. The stirred dispersion of reinforcing fibers is randomly sampled with a measuring spoon to obtain an evaluation sample, and the length of 3,000 reinforcing fibers (I = 3,000) is measured using a Luzex AP image analyzer manufactured by Nireco Corporation. The weight average fiber length Lw can be calculated using the measured fiber length values ​​L1 to L3,000 in the same manner as in the above formula (1).

[0044] [Volume fraction of reinforcing fibers in sheet-shaped composite material and injection molding material] The volume fraction of reinforcing fibers (Vf) can be calculated for each of the composite material and injection molding material by the following formula (2): Volume fraction of reinforcing fibers (Vf) = 100 × volume of reinforcing fibers / (volume of reinforcing fibers + volume of resin) Formula (2)

[0045] There is no particular limitation on the volume fraction of the reinforcing fibers contained in the composite material, but the volume fraction (Vfa) of the reinforcing fibers 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] In general, injection molding materials with higher fluidity than composite materials often have a lower fiber volume fraction (Vfb) than the fiber volume fraction (Vfa) of the composite material, with Vfa > Vfb. The volume fraction (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 Reinforcing Fiber Volume Fraction (Vf)] Although there are no limitations on the analysis of the reinforcing fiber volume fraction, it is recommended to measure it as follows. A sample is cut out from the reinforcement section or the main body section (and the laminate injection section), and the resin is burned off in a furnace at 500°C for 1 hour. The masses of the sample before and after treatment are weighed to calculate the masses of the reinforcing fibers and resin. Next, the volume fraction of the reinforcing fibers and resin is calculated using the specific gravity of each component. Vf = 100 x reinforcing fiber volume / (reinforcing fiber volume + resin volume)

[0048] [Resin] The resin contained in the composite material and the resin contained in the injection molding material may be either thermosetting or thermoplastic. 1. Thermoplastic Resin 1.1 Overview When the resin used is a thermoplastic resin, the type is not particularly limited, and a resin having the desired softening point or melting point can be appropriately selected and used. As the above-mentioned thermoplastic resin, one having a softening point in the range of 180°C to 350°C is usually used, but is not limited thereto.

[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, polyether ketone resins, thermoplastic urethane resins, fluorine-based resins, and thermoplastic polybenzimidazole resins.

[0050] The thermoplastic resin used in the sheet-like composite material and the injection molding material 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.

[0051] When a thermoplastic resin is used, it is more preferable to use a polyolefin resin, and even more preferable to use a polypropylene resin.

[0052] 1.2 Resin of the sheet-shaped composite material and injection molding material The resin contained in the composite material is preferably a thermoplastic resin. If the resin contained in the composite material is a thermoplastic resin, it is more preferable that the resins contained in the composite material and the injection molding material are the same type of thermoplastic resin.

[0053] 2. Thermosetting Resin The resin contained 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 into even complex shapes. Sheet molding compounds have higher fluidity and formability than continuous fibers, making it easy to create ribs and bosses.

[0054] [Other Agents] The resin used in the composite material or injection 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., within the scope of the present invention.

[0055] [Preferred fiber combination] The reinforcing fibers contained in the composite material are preferably glass fibers and / or carbon fibers, and the reinforcing fibers contained in the injection molding material are preferably glass fibers. Carbon fibers may be used partially as the reinforcing fibers contained in the composite material, and glass fibers may be used in the portions other than the portions using carbon fibers. When holes h are formed in the molded body, the portion where carbon fibers are used in the composite material is preferably the portion surrounding the holes h.

[0056] [Integral molding] The manufacturing method of the molded body of this embodiment involves integral molding using a composite material and an injection molding material. Integral molding means that these are molded continuously without any seams, and are not formed by joining separate components together. Such integral molding creates a structure in a single molding operation, and can be achieved preferably by press molding. Because it is created by integral molding, separate parts can be processed as a single part, making it possible to reduce the unit price of the part. In addition, the number of assembly steps is reduced, and the reduction in the number of parts also makes it possible to reduce inventory costs.

[0057] [Manufacturing Method] The manufacturing method for a molded body of this embodiment is a manufacturing method for a molded body integrally molded with a composite material containing reinforcing fibers dispersed in the in-plane direction and a resin and an injection molding material using a first molding die and a second molding die, and includes the following steps 101 to 401. Step 101: A step of placing the composite material in the cavity of the first molding die. Step 201: A step of moving the second molding die toward the placed composite material. Step 301: A step of injecting the injection molding material into the molding die through a first gate and a second gate provided on the first molding die. Step 401: A step of pressing the composite material and the injection molding material in the molding die to integrally mold the molded body. By integrally molding the composite material and the injection molding material, a molded body with excellent bonding strength between the reinforcing portion, the main body portion, and the laminated injection portion can be obtained. Furthermore, by pressing the composite material and the injection molding material, a molded body with a complex shape having ribs and bosses can be produced.

[0058] [Manufacturing Step in the Case of Cold Pressing: Step 001] When the resin contained in the composite material and the injection molding material is a thermoplastic resin, it is preferable to use cold press molding. The manufacturing method for manufacturing a molded product by cold press molding includes, before step 101, step 001, "Step 001: heating the composite material to a first predetermined temperature."

[0059] When the 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 and below the decomposition temperature of the thermoplastic resin. If the thermoplastic resin contained in the composite material is amorphous, the first predetermined temperature is a temperature above the glass transition temperature and below the decomposition temperature of the thermoplastic resin.

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

[0061] [Manufacturing Method: Step 101] Step 101 is a step of placing a composite material in the cavity of a 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 observed on the mold when placed in the mold. For example, FIG. 4 depicts a composite material 105 placed along the first mold 108. The area of ​​the composite material refers to the area of ​​the composite material 105 observed from 301 (eye) in FIG. 4 (the area of ​​the front surface of the composite material) and does not include the area of ​​the portion in contact with the mold 108 (the area of ​​the back surface of the composite material). In other words, the area of ​​the composite material refers to the area of ​​one side of the composite material, not the total area of ​​the front and back surfaces of the composite material, nor is it a projected area.

[0062] The composite material is preferably pre-shaped and placed in the cavity of the first mold so as to fit the cavity of the first mold, although the pre-shaping does not need to fit perfectly to the cavity of the first mold.

[0063] In this embodiment, the area of ​​the deposited composite material is smaller than the area of ​​the first mold cavity, so there are areas in the first mold cavity where no composite material is deposited.

[0064] The composite material is preferably fixed in the cavity of the first mold by a plurality of fixing members. The fixing members may be, for example, slide cores that form holes in the molded body. For example, holes may be formed in the composite material in advance, and the fixing members may be inserted into the holes in the composite material to fix the composite material. Alternatively, the composite material may be fixed by piercing pin-shaped fixing members into the composite material. In this case, holes need not be formed in the composite material.

[0065] It is preferable that the composite material be placed only within the cavity of the first mold, since this eliminates the need for additional equipment and makes the molding process less complicated than when the composite material is placed all the way to the outer periphery of the cavity and fixed at the outer periphery.

[0066] [Manufacturing method: step 201] This is a step of moving a second mold toward the arranged composite material. The second mold may be moved until it contacts the composite material, but if the injection molding material is poured just before the second mold contacts the composite material in step 301, step 201 covers the period up to the pouring of the injection molding material.

[0067] [Manufacturing method: Step 301] 1. Heating of injection molding material When the injection molding material is introduced into the mold, it is preferably heated to a temperature above the melting point and below the decomposition temperature of the thermoplastic resin if the thermoplastic resin contained in the injection molding material is crystalline, or above the glass transition temperature and below the decomposition temperature of the thermoplastic resin if the thermoplastic resin is amorphous. Heating is preferably carried out in a kneading step.

[0068] 2. Timing of Injection of Injection Molding Material The injection molding material is introduced into the mold in step 301. The injection molding material may be injected immediately before or immediately after pressure begins to be applied from the second mold to a portion of the composite material. 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 the injection molding material, the movement of the second mold may be stopped once before the mold is completely closed. The position at which the movement of the second mold is stopped is preferably after the second mold comes into contact with the composite material.

[0069] 3. Gate Location 3.1 The 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 in the first mold (108) to inject the first injection molding material 111 and the second injection molding material 112.

[0070] 3.2 First Gate The first gate is installed in the area where the composite material 105 is placed. Figure 5 illustrates the state immediately after the composite material 105 is placed in the first molding die 108. In Figure 5, the area where the composite material 105 is in contact with the first molding die 108 is the area where the composite material 105 is placed. The first gates (101, 103), which are injection gates, are installed in advance in this area.

[0071] 3.3 Second Gate The second gate 102 is placed in a cavity region of the first molding die 108 where the composite material 105 is not placed. For example, the second gate 102 in Fig. 5 is placed in a position where the composite material 105 is not in contact with the cavity of the first molding die 108. The position of the second gate 102 is determined in advance by working backwards from the position where the composite material 105 is placed.

[0072] 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. Note that, as shown in FIG. 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 X1. Similarly, if there are multiple second gates, the distance from the second gate 102 closest to the end of the composite material 105 to the end of the composite material 105 is X2.

[0073] 3.4.1 X1 and X2 Figure 5 illustrates an example 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 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) are viewed in plan, and a straight line is drawn between the first gate 101 and the second gate 102, X1 is the distance between the first gate 101 and a position P where the line intersects with the end of the composite material 105. If the composite material 105 is bent along the first molding die 108 as shown in Figure 6, X1 is the distance between the position P and the first gate 101 as measured by the creepage distance of the cavity surface of the first molding die 108. If the distance X1 is relatively short, the first injection molding 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 the composite material 105, the first gate 101, and the second gate 102 are viewed in plan, and a straight line is drawn connecting the first gate 101 and the second gate 102, X2 is the distance between the second gate 102 and a position P where the line intersects with the end of the composite material 105. If the cavity surface of the first molding die 108 is bent as shown in FIG. 7, X2 is the distance between the position P and the second gate 102 when measured using the creepage distance of the cavity surface of the first molding die 108. By ensuring a certain distance X2, the second injection molding 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 injection amount of first injection molding material 111 injected from first gates 101, 103 provided in the area where composite material 105 is placed in the plan view of the mold cavity. V2 is the injection amount of second injection molding material 112 injected from second gate 102 provided in an area other than the area where composite material is placed in the plan view of the mold cavity.

[0076] When the injection amount V1 of the first injection molding material 111 injected from the first gates 101, 103 is large, the first injection molding material 111 from the first gates 101, 103 tends to spread into the mold cavity quickly. Conversely, when the injection amount V1 is small, the first injection molding material 111 spreads into the mold cavity more slowly. When the injection amount V1 is small, for example, as shown by reference numeral 205 in FIG. 3B , the end of the composite material 105 is more likely to be wedged between the first injection molding material 111 and the second injection molding material 112.

[0077] If the injection amount V2 of the second injection molding material 112 injected from the second gate 102 is small, the second injection molding material 112 injected from the second gate 102 will spread into the mold cavity at a slower rate. Conversely, if the injection amount V2 is large, the second injection molding material 112 will spread into the mold cavity at a faster rate. If the injection amount V2 is large, there is an increased possibility that the end of the composite material 105 will be wedged between the first injection molding material 111 and the second injection molding material 112, as shown by reference numeral 205 in FIG. 3B , for example.

[0078] 3.4.3 V1 / (X1 × volume of stacking injection part) > V2 / (X2 × volume of main body part) When V1 / (X1 × volume of stacking injection part) > V2 / (X2 × volume of main body part) is satisfied, it is possible to effectively prevent the ends of the material with low fluidity (composite material) in the molding die from being wedged between the fluid injected materials. More preferably, V1 / X1 > ((V2 / X2) × 0.5), and even more preferably, V1 / X1 > V2 / X2.

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

[0080] In addition, the larger the volume of the main body portion 903 is compared to the stacked injection portion 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. In general, injection molding materials have large cavity spaces and flow in the direction in which the shear force generated during flow is small. The gap 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 gap. On the other hand, if the volume of the main body portion 903 is large, the second injection molding material 112 will begin to fill the large cavity space used to form the main body portion 903 first. Since the shear force generated during flow in a large cavity space is relatively low, the main body portion 903 is formed before the injection molding material 2 enters between the composite material and the second molding die, and therefore even if V2 is large or X2 is short, the composite material 105 is prevented from entering between the second molding die 107.

[0081] Furthermore, when the size of the layer injection portion 902 is small, even when V1 is small or X1 is long, filling by the first injection molding material 111 is completed relatively quickly. As a result, the layer injection portion 902 is formed by the first injection molding material 111 before the main body portion 903 is formed by the second injection molding material 112. At this time, the first injection molding material 111 can easily reach the end of the composite material 105 before the second injection molding material 112.

[0082] In other words, by satisfying V1 / (X1 × volume of stacked injection section) > V2 / (X2 × volume of main body section), the weld line 109 formed between 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 positioned outside the area where the composite material 105 is placed, thereby preventing the end of the composite material 105 from being bitten into by the injection molding materials 111 and 112 (e.g., reference numeral 205 in FIG. 3B ). In the preferred manufacturing method of this embodiment, the weld line 109 formed between 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 is positioned outside the area where the composite material is placed after molding is completed. In this case, the flow length of the first injection molding material 111 is longer than X1 (e.g., FIG. 2 ). Note that, since composite material 105 may move during molding, the location where composite material 105 is placed in step 101 does not necessarily match the region where composite material 105 is placed after molding is complete. Furthermore, since composite material 105 may be called reinforcing portion 901 after molding, the region where composite material 105 is placed after molding is complete can be called the region where reinforcing portion 901 is placed after molding is complete.

[0083] Conversely, if V1 / (X1 × volume of the stacking injection part) < V2 / (X2 × volume of the main body part), the end of composite material 105 will be wedged between first injection molding material 111 and second injection molding material 112, as shown by reference numeral 205 in FIG. 3B. Note that in this embodiment, it is not necessary to fix composite material 105 at the outer periphery of the cavity of the mold. This is because satisfying V1 / (X1 × volume of the stacking injection part) > V2 / (X2 × volume of the main body part) can prevent the composite material from shifting significantly in position within the mold.

[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, even 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, even 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, and even 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, and even more preferably 80 ml or more and 600 ml or less.

[0088] The volume of the stacked injection part 902 is 10 cm ３ More than 1100cm ３ Preferably less than 30 cm ３ More than 900cm ３ Less than 50 cm is more preferable. ３ More than 700cm ３ The following is even more preferred:

[0089] The volume of the main body 903 is 20 cm ３ More than 1100cm ３ Preferably less than 40 cm ３ More than 900cm ３ Less than 90cm is more preferable. ３More than 700cm ３ The following is even more preferred:

[0090] The volume of the reinforcing part 901 is 10 cm ３ More than 1100cm ３ Preferably less than 30 cm ３ More than 900cm ３ Less than 50 cm is more preferable. ３ More than 700cm ３ The following is even more preferred:

[0091] 3.5 Location of weld lines A weld line is a linear pattern that appears in a molded product obtained by a molding method that melts and flows resin materials, where the flows of molten resin meet inside the mold during molding. It is also called a weld or weld part. It is so named after the linear weld marks that appear when metal materials are welded together.

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

[0093] In other words, it is preferable that 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 occurs outside the area where the reinforcing portion 901 is arranged after molding is completed. By generating the weld line 109 outside the area where the composite material 105 is arranged after molding is completed, it is possible to prevent the end of the composite material 105 from being bitten into by the injection molding material.

[0094] 3.6 In this embodiment, there may be a plurality of first gates, and similarly, there may be a plurality of second gates. For example, the gate designated by reference numeral 103 in Fig. 1 is a gate located in the region where the composite material 105 is disposed, and therefore corresponds to the first gate in this embodiment.

[0095] When there are multiple first gates and multiple second gates, it is sufficient that at least one pair of first gates and second gates satisfy the relationship V1 / (X1 × volume of stacked injection section) > V2 / (X2 × volume of main body section). When there are multiple first gates and multiple second gates, if the total amount of first injection molding material injected from all first gates is V1 and the total amount of first injection molding material injected from all second gates is V2, V1, V2, X1, and X2 may satisfy the relationship V1 / (X1 × volume of stacked injection section) > V2 / (X2 × volume of main body section). Here, when a line is drawn between 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 position where the line intersects with the end of the composite material is designated P, the distance between the first gate closest to the end of the composite material and P is designated X1, and the distance between the second gate closest to the end of the composite material and P is X2.

[0096] 4. Penetration of Injection Molding Material In this embodiment, at the completion of molding, the injection molding material does not penetrate between the composite material and the second mold. This results in a good appearance design surface formed by the second mold. If the injection molding material penetrates between the composite material and the second mold, the design surface of the composite material will not be visible and will not be beautiful. Furthermore, since the injection molding material does not penetrate between the composite material and the second mold, the reinforcing portion can fully utilize the mechanical strength of the composite material and can express the physical properties of the reinforcing fibers randomly dispersed in two dimensions contained in the reinforcing portion.

[0097] It should be noted that the injection molding material may get into the gap between the composite material and the second mold in either step 301 or step 401, but in this embodiment, the injection molding material does not get into the gap between the composite material and the second mold in either step 301 or step 401.

[0098] 5. Blocking of Injection Molding Material In step 301, it is preferable for the second mold to contact the composite material to block the injection molding material. For example, when the composite material 105 is held down by the upper mold 107 (second mold) as shown in Figure 8, the upper mold 107 can contact the composite material 105 to block the second injection molding material 112. In this case, it is preferable for the cavity space in the relatively large mold to expand in the direction indicated by 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. Flow rate control There are no particular limitations on the method for controlling the flow rate of injection molding material, but shortening the mold clamping time or mold clamping distance during molding will increase the flow rate of the injection molding material. The flow rate of the injection molding material also depends on the amount of injection molding material added.

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

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

[0102] On the other hand, if the maximum flow speed of first injection molding material 111 injected from the first gate is 200 mm / sec or less, the placed composite material 105 is prevented from being swept away, torn, or shifted by first injection molding material 111. In other words, when first injection molding material 111 flows, a shear force is generated on the inner wall surface of second mold 107 and composite material 105 depending on the flow speed. By setting the maximum flow speed of first injection molding material 111 to 200 mm / sec or less, the shear force is suppressed, and it is possible to prevent composite material 105 from being torn apart.

[0103] The maximum flow speed of the first injection molding material 111 is more preferably 10 mm / sec or more and 200 mm / sec or less, and even more preferably 30 mm / sec or more and 150 mm / sec or less. The flow time of the second injection molding material injected from the second gate is preferably longer than the flow time of the first injection molding 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. The flow rate in this embodiment does not refer to the cylinder movement speed, but rather to the movement speed of the resin within the mold.

[0105] [Location of injection molding material] It is preferable that the injection molding material 111 injected from the first gate 101 is filled between the first molding die 108 and the composite material 105. When the injection molding material 111 is filled into the molding die, the composite material 105 is pressed against the cavity surface of the second molding die 107, thereby preventing the composite material 105 from shifting position. Figure 1 shows the composite material 105 being pressed against the second molding die 107.

[0106] [Manufacturing Method: Step 401] 1. The composite material and injection molding material are pressed together using a first mold and a second mold to form a single body. The molding pressure is not particularly limited, but is preferably less than 20 MPa, and more preferably 10 MPa or less. When the composite material and 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. The second mold is then moved away from the first mold, and the molded body is removed from the first mold. This completes the molded body.

[0107] [Manufacturing method: Mold] In this embodiment, the first mold and the second mold are preferably a pair of male and female molds. When a first mold and a second mold are used, 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. Note that, depending on the mold, the fixed mold may move. If the fixed mold moves, the mold that moves a relatively small distance is called the fixed mold, and the mold that moves a relatively large distance is called the movable mold.

[0108] Alternatively, the molds may be a pair of upper and lower molds, with the first mold being the lower mold and the second mold being the upper mold, and in this case the second mold may be opened and closed by moving up and down toward the first mold.The molds may also be molds that open and close by moving at least one of the first mold and the second mold horizontally to form the mold.

[0109] The present invention will be described in detail below using examples, but the present invention is not limited to these. 1. Materials 1.1 Polypropylene Resin - Resin for composite materials: Novatec PP BC03C manufactured by Japan Polypropylene Corporation - Fiber reinforced resin for injection molding materials: Mostron L-4070P manufactured by Prime Polymer (glass fiber weight ratio 40%) 1.2 Glass Fiber Glass fiber E-glass RS240QR-483 manufactured by Nitto Boseki Co., Ltd. was prepared with a sizing agent attached (sometimes abbreviated as GF).

[0110] 2. Evaluation Method 2.1 Analysis of Reinforcing Fiber Volume Fraction (Vf) A molded product was cut out from a region made of composite material or a region made of injection molding material, and the resin was burned off in a furnace at 500°C for 1 hour. The masses of the reinforcing fibers and resin were calculated by weighing the masses of the sample before and after treatment. Next, the volume fraction of the reinforcing fibers and resin was calculated using the specific gravity of each component. Reinforcing fiber volume fraction (Vf) = 100 × reinforcing fiber volume / (reinforcing fiber volume + resin volume) Equation (2)

[0111] 2.2 Analysis of Weight-Average Fiber Length: The weight-average fiber length of the reinforcing fibers contained in the molded product was measured by first removing the resin in a furnace at 500°C for approximately 1 hour. 2.2.1 Reinforcing Fibers Contained in Composite Materials: After removing the composite material from the molded product and removing the resin, the lengths of 100 randomly selected glass fibers were measured to the nearest 1 mm using a vernier caliper and recorded. The weight-average fiber length (LwA) was calculated using the aforementioned formula (1) from the lengths of all the measured glass fibers (Li, where i = an integer from 1 to 100). 2.2.2 Reinforcing Fibers Contained in Injection Molding Materials: After removing the 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 vibrations. The stirred dispersion was randomly sampled with a measuring spoon to obtain evaluation samples, and the lengths of 3,000 fibers were measured using a Nireco Luzex AP image analyzer. The measured fiber length was used to calculate the weight average fiber length Lw in the same manner as in the above-mentioned formula (1).

[0112] Example 1 (1) Preparation of Composite Material: Nitto Boseki Co., Ltd.'s E-glass RS240QR-483 glass fiber, cut to a fiber length of 20 mm, was used as the glass fiber. Japan Polypropylene Corporation's Novatec PP BC03C polypropylene resin was used as the resin. A composite composition of glass fiber and polypropylene resin with two-dimensionally randomly oriented glass fibers was prepared based on the method described in U.S. Patent No. 1,000,677. The resulting composite composition was heated at 2.0 MPa for 5 minutes in a press heated to 250°C to produce a flat composite material with an average thickness of 3 mm and dimensions of 300 mm x 500 mm. The fiber volume fraction (Vf) was 35%.

[0113] (2) Preparation of the molding die Upper and lower molding dies were prepared, with the lower molding die being the first molding die and the upper molding die being the second molding die. The molding die cavity was a rectangular (flat) shape measuring 300 mm x 806 mm, with one first gate and one second gate installed. The design volumes of the reinforcement part, stacking injection part, and main body part are listed in Table 1.

[0114] (3) Production of molded body The composite material was dried for 4 hours in a hot air dryer at 120°C, and then heated to 220°C using an infrared heater, and the composite material 105 was placed in a lower molding die 108 as shown in Fig. 5. More specifically, the composite material 105, measuring 300 mm long and 500 mm wide, was placed so as to be aligned with the edge of a flat mold cavity measuring 300 mm long and 806 mm wide.

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

[0116] The mold temperature was set to 50°C, the mold was closed, and after confirming with a pressure gauge that pressure had begun to be applied to a portion of composite material 105, injection was performed using a Mostron L-4070P manufactured by Prime Polymer Co., Ltd., 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 240°C.

[0117] Thereafter, the composite material 105, the injection molding material 1, and the injection molding material 2 were pressed together at a pressure of 20 MPa for 1 minute to produce a molded body.

[0118] (4) Observation of the molded body The end of the composite material was observed to be pinched between injection molding material 1 and injection molding material 2, and any disruption to the positioning of the composite material. When molding was completed, a reinforcing portion 1001, a main body portion 1003, and a laminated injection portion 1002 were formed, as shown in Figure 10. The weld line formed between injection molding material 1 and injection molding material 2 was located at 1004. The end of composite material 1001 was not pinched between injection molding material 1 and injection molding material 2. No disruption to the positioning of composite material 1001 was observed. The results are shown in Table 1.

[0119] The volume of main body 1003 is greater than injection amount V2 of injection molding material 2, and it can be seen that main body 1003 is formed from injection molding material 1 and injection molding material 2.

[0120] Example 2 A molded body was produced in the same manner as in Example 1, except that the size of the composite material, the injection amounts of injection molding material 1 and injection molding material 2, and the distance X2 were changed as shown in Table 1. The end of composite material 1001 was not pinched between injection molding material 1 and injection molding material 2. Furthermore, no disturbance in the positioning of composite material 1001 was observed. The results are shown in Table 1.

[0121] Example 3 A molded body was produced in the same manner as in Example 1, except that the mold clamping time was shortened to increase the flow rate as shown in Table 1. The end of composite material 1001 was not pinched between injection molding material 1 and injection molding material 2. Some disorder in the arrangement of composite material 1001 was observed. The results are shown in Table 1.

[0122] Comparative Example 1 A molded body was produced in the same manner as in Example 1, except that the injection amount of injection molding material 1, the injection amount of injection molding material 2, the distance X1, and the distance X2 were changed as shown in Table 1. The results are shown in Table 1. Because the distance X1 was long and the distance X2 was short, the end of the composite material was pinched between injection molding material 1 and injection molding material 2. No disturbance in the positioning of composite material 1001 was observed. The results are shown in Table 1.

[0123]

Claims

1. A method for producing a molded body integrally molded with a sheet-like composite material containing reinforcing fibers and resin dispersed in an in-plane direction and an injection molding material using a first molding die and a second molding die, the method comprising the following steps 101 to 401: step 101: a step of placing the sheet-like composite material in a cavity of the first molding die; step 201: a step of moving a second molding die toward the placed sheet-like composite material; step 301: a step of injecting the injection molding material into the molding die from a first gate and a second gate provided on the first molding die; step 401: a step of pressing the sheet-like composite material and the injection molding material in the molding die to integrally mold the molded body, with the proviso that: (a) in step 101, the cavity area of ​​the first molding die is larger than the area of ​​the placed sheet-like composite material, (b) the position of the first gate is in an area where the sheet-like composite material is placed in step 301, and the position of the second gate is in an area where the sheet-like composite material is not placed in step 301; and (c) when molding is completed, no injection molding material gets between the sheet-like composite material and the second mold.

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

3. A method for producing a molded body as described in either claim 1 or 2, wherein a weld line formed by the first injection molding material injected from the first gate and the second injection molding material injected from the second gate occurs outside the area where the sheet-like composite material is placed after molding is completed.

4. A method for producing a molded product as claimed in any one of claims 1 to 3, wherein in the produced molded product, a portion formed by the sheet-like composite material is a reinforcing portion, a portion formed by the injection molding material in a layered relationship with the reinforcing portion is a layered injection portion, and a portion formed by the injection molding material other than the layered injection portion is a main body portion, and in step 301, when the injection amount of the first injection molding material injected from the first gate is V1, the injection amount of the second injection molding material injected from the second gate is V2, the distance from the first gate to the end of the sheet-like composite material is X1, and the distance from the second gate to the end of the sheet-like composite material is X2, the relationship V1 / (X1 x volume of layered injection portion)>V2 / (X2 x volume of main body portion) is satisfied.

5. A method for producing a molded product according to claim 4, wherein when the first gate and the second gate are connected by a straight line and a position P is defined as a point where the line intersects with an end of the sheet-like composite material, X1 is the distance between position P and the first gate, and X2 is the distance between position P and the second gate.

6. A method for producing a molded article according to any one of claims 3 to 5, wherein the first injection molding material reaches an end of the sheet-like composite material before the second injection molding material.

7. A method for producing a molded body according to any one of claims 4 to 6, 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 producing a molded article according to any one of claims 1 to 7, wherein in step 301, the second mold contacts the sheet-like composite material to block the injection molding material.

9. A method for producing a molded article according to any one of claims 1 to 8, wherein in step 101, the sheet-like composite material is placed only within the cavity of a first mold.

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