Method for manufacturing molded body

Abstract

When a composite material and an injection molding material are integrally molded, the tip of the composite material is prevented from being pinched by the injection molding material. A method for producing a molded body by integrally molding a composite material containing reinforcing fibers and a resin dispersed in the in-plane direction and an injection molding material using a first molding die and a second molding die, the method comprising the following steps 101-401: step 101: a step of disposing the sheet-like composite material in a cavity of the first molding die; step 201: a step for moving a second molding die toward the arranged composite material; step 301: a step for injecting the injection molding material into a molding die from a first gate and a second gate provided in the first molding die; a step (401) for integrally molding the molded body by pressing the sheet-like composite material and the injection-molded material in a molding die: (a) in step (101), the cavity area of the first molding die is larger than the area of the composite material that has been arranged, and (b) in step (301), the position of the first gate is located in the region where the sheet-like composite material has been arranged, and the position of the second gate is located in the region where the sheet-like composite material has been arranged. And (c) when the molding is completed, the injection molding material does not enter the space between the composite material and the second molding mold.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a molded body integrally formed by using a sheet-shaped composite material and an injection molding material having a higher fluidity than the sheet-shaped composite material. Background Art

[0002] For composite materials using reinforcing fibers such as carbon fibers and glass fibers as reinforcing materials, due to their high tensile strength, high tensile elastic modulus, and small linear expansion coefficient, they have excellent dimensional stability. Furthermore, they also have excellent heat resistance, chemical resistance, fatigue resistance, abrasion resistance, electromagnetic wave shielding property, and X-ray transmissibility. Therefore, composite materials are widely applied to automotive, sports and leisure, aerospace, general industrial uses, etc.

[0003] However, methods for integrally manufacturing a molded body from a plurality of different materials are being studied. For example, Patent Document 1 discloses a die device in which while pressing and clamping the peripheral portion of a skin material into a pin seat hole, a pin is engaged with the pin seat hole, and the pressing surface of a pressing frame and the skin material placement surface of a lower die are used for pressing and holding. After supplying a molten thermoplastic resin between the skin material held by the lower die and the molding surface of the upper die, when mold clamping is started, the molten thermoplastic resin flows, and the skin material is pressed by mold clamping, contracts toward the inside of the mold while being stretched along the shape of the die. At the same time, the peripheral portion of the skin material slides between the pin and the pin seat hole and between the pressing surface and the skin material placement surface, and is pulled into the inside direction of the die.

[0004] Patent Document 2 discloses the following technique: As a die for press molding a sheet in which a discontinuous fiber-reinforced thermoplastic resin layer is laminated on at least a part of one surface of a continuous fiber-reinforced thermoplastic resin layer to manufacture a fiber-reinforced thermoplastic resin molded product, a die is used in which a frame-shaped weir portion for preventing the discontinuous fiber-reinforced thermoplastic resin layer from flowing out of the cavity is provided on the outer peripheral edge of the cavity, and a gap for extending the continuous fiber-reinforced thermoplastic resin layer to the outside of the cavity is formed.

[0005] Patent Document 3 discloses the following content: An auxiliary die that can slide up and down is disposed in close contact with the outer peripheral wall of the lower die of a stamping die, and a thermoplastic resin melt between the upper die and the lower die of the stamping die is press molded as a base material. When a skin material is press-bonded to the base material, the auxiliary die is used to prevent the melt from leaking between the upper die and the lower die.

[0006] The manufacturing method provided in Patent Document 4 manufactures an injection molded product that encloses multiple sheet materials at a lower cost. As specific steps, the following is described. First, the gate nozzle is extended, and resin is injected and bonded between the outer sheet and the adjacent reinforcing member resin-impregnated sheet. Next, the movable mold is moved to the side opposite to the fixed mold, and the outer sheet and the reinforcing member resin-impregnated sheet move together with the movable mold. Then, the reinforcing member resin-impregnated sheet that has been bonded to the outer sheet and the reinforcing member resin-impregnated sheet located beside it are bonded. Finally, the moving process and the bonded sheet bonding process are repeated the number of times corresponding to the number of reinforcing member resin-impregnated sheets - 1.

[0007] Patent Document 5 describes a molding method in which an injection molding material flows from an area other than the vertical surface to the vertical surface.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent No. 3413356 Gazette

[0011] Patent Document 2: Japanese Patent No. 5855401 Gazette

[0012] Patent Document 3: Japanese Unexamined Patent Application Publication No. 9-117922

[0013] Patent Document 4: Japanese Unexamined Patent Application Publication No. 2020-179549

[0014] Patent Document 5: WO2020 / 196076 Summary of the Invention

[0015] Technical Problem to be Solved by the Invention

[0016] However, in the case of integrally molding multiple materials with different fluidities in a molding die, the end of the material with low fluidity (sheet composite material) in the molding die may be enclosed between the injection molding materials with high fluidity.

[0017] As a further problem of the present invention, if the filling speed of the injection molding material in the molding die is too fast, for the sheet composite material with low fluidity, there will be problems such as: (i) misalignment of orientation, (ii) generation of wrinkles, (iii) elongation, and breakage. On the contrary, if the filling speed is too slow, the spread of the injection material in the molding die is insufficient, resulting in poor filling of the injection molding material and poor appearance.

[0018] Regarding this point, in the method of Patent Document 1, the skin material is fixed by holding it at the outer peripheral part of the mold. However, in the case of insert molding or the like where a material with low fluidity is completely injection molded from the cavity of the mold, the method of Patent Document 1 cannot be applied.

[0019] In the method of Patent Document 2, although a weir portion for preventing the outflow of the discontinuous fiber-reinforced thermoplastic resin layer is provided on the outer peripheral edge of the cavity, there is no study on the case where a sheet-like composite material with low fluidity is completely disposed in the cavity of the mold.

[0020] In the method of Patent Document 3, a skin material is held outside the molding die using a jig. However, in the case where a material with low fluidity such as insert molding is completely disposed in the cavity of the mold, the method of Patent Document 3 cannot be applied during molding.

[0021] In the method of Patent Document 4, as a reinforcing member resin impregnated sheet, a sheet obtained by impregnating a plain weave fabric of glass fibers with a wire diameter of about 17 μm with a polypropylene resin is used. In the case of using fibers such as a plain weave fabric in which reinforcing fibers are continuously oriented in a specific direction, it is difficult to obtain target physical properties even if there is a slight deviation (even if there is a deviation of several millimeters) in the arrangement when injecting an injection material and performing compression molding. Therefore, measures need to be taken for the molding die to prevent the reinforcing member resin impregnated sheet from deviating. In particular, in the case where it is desired to impregnate resin between multiple sheets of reinforcing members, the process becomes too complicated.

[0022] In the method of Patent Document 5, the study on setting two or more gate positions during the filling of the injection molding material is insufficient.

[0023] An object of the present invention is to provide a method for manufacturing a molded body that does not fix a sheet-like composite material to the outer peripheral portion of the cavity of a molding die when integrally molding the sheet-like composite material and an injection molding material.

[0024] Technical means for solving the problem

[0025] To solve the above problems, the present invention provides the following solutions.

[0026] 1. A method for manufacturing a molded body, characterized in that

[0027] it is a method for manufacturing a molded body that integrally molds a sheet-like composite material containing reinforcing fibers and resin dispersed in the in-plane direction and an injection molding material using a first molding die and a second molding die, and includes the following steps 101 to 401:

[0028] Step 101: A step of disposing the sheet-like composite material in the cavity of the first molding die;

[0029] Step 201: A step of moving the second molding die toward the disposed sheet-like composite material;

[0030] Process 301: A process of injecting the injection molding material into the molding die from a first gate and a second gate that have been provided in the first molding die;

[0031] Process 401: A process of pressing the sheet-like composite material and the injection molding material in the molding die to integrally form the molded body.

[0032] Among them, (a) in Process 101, the cavity area of the first molding die is larger than the area of the sheet-like composite material after being arranged;

[0033] (b) The position of the first gate is located in the area where the sheet-like composite material is arranged in Process 301, and the position of the second gate is located in the area where the sheet-like composite material is not arranged in Process 301;

[0034] (c) When the molding is completed, the injection molding material does not enter between the sheet-like composite material and the second molding die.

[0035] 2. The manufacturing method of the molded body according to item 1 above, wherein,

[0036] 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.

[0037] 3. The manufacturing method of the molded body according to any one of items 1 or 2 above, wherein,

[0038] The 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 is generated outside the area where the sheet-like composite material is arranged after the molding is completed.

[0039] 4. The manufacturing method of the molded body according to any one of items 1 to 3 above, wherein,

[0040] In the manufactured molded body, the part formed by the sheet-like composite material is used as a strengthening part, the part formed by the injection molding material in a laminated relationship with the strengthening part is used as a laminated injection part, and the part formed by the injection molding material other than the laminated injection part is used as a main body part.

[0041] In Process 301, when the injection amount of the first injection molding material injected from the first gate is set as V1, the injection amount of the second injection molding material injected from the second gate is set as V2, the distance from the first gate to the end of the sheet-like composite material is set as X1, and the distance from the second gate to the end of the sheet-like composite material is set as X2,

[0042] It satisfies V1 / (X1 × volume of the laminated injection part) > V2 / (X2 × volume of the main body part).

[0043] 5. The manufacturing method of the molded body according to 4 above, wherein,

[0044] When the first gate and the second gate are linearly connected and the position where the straight line intersects the end of the sheet-shaped composite material is position P,

[0045] X1 is the distance between position P and the first gate,

[0046] X2 is the distance between position P and the second gate.

[0047] 6. The manufacturing method of the molded body according to any one of 3 to 5 above, wherein,

[0048] The first injection molding material reaches the end of the sheet-shaped composite material earlier than the second injection molding material.

[0049] 7. The manufacturing method of the molded body according to any one of 4 to 6 above, wherein,

[0050] 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.

[0051] 8. The manufacturing method of the molded body according to any one of 1 to 7 above, wherein,

[0052] In step 301, the second molding die contacts the sheet-shaped composite material to intercept the injection molding material.

[0053] 9. The manufacturing method of the molded body according to any one of 1 to 8 above, wherein,

[0054] In step 101, the sheet-shaped composite material is disposed only in the cavity of the first molding die.

[0055] Advantages of the Invention

[0056] For the molded body manufactured by the manufacturing method of the present invention, at the end of molding, the injection molding material does not enter between the sheet-shaped composite material and the second molding die, so that the physical properties of the sheet-shaped composite material can be fully exerted and the appearance design is excellent.

[0057] In addition, without fixing the sheet-shaped composite material to the outside of the cavity of the molding die, the position deviation of the sheet-shaped composite material in the molding die can be prevented.

[0058] Furthermore, by using a sheet-shaped composite material containing reinforcing fibers dispersed in the in-plane direction, even if the sheet-shaped composite material slightly flows during molding, the basic mechanical properties will not change significantly. In addition, the shape followability is also improved compared to the case of using continuous fibers such as plain weave fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram showing the relationship between the injection gate and the sheet-shaped composite material in the molding process 301 of the present invention.

[0060] Figure 2 It is a schematic diagram showing the relationship between the injection gate and the sheet-shaped composite material in the molding process 301 of the present invention.

[0061] Figure 3A It is a schematic diagram showing the relationship between the injection gate and the sheet-shaped composite material in the case where V1 < V2 and X1 > X2 in the molding process 301.

[0062] Figure 3B It is a schematic diagram showing the relationship between the injection gate and the sheet-shaped composite material in the case where V1 < V2 and X1 > X2 in the molding process 301.

[0063] Figure 4 It is a schematic diagram showing the state in which the sheet-shaped composite material is arranged along the first molding die.

[0064] Figure 5 It is a schematic diagram showing the positional relationship between the injection gate and the arrangement area of the sheet-shaped composite material in the process 101.

[0065] Figure 6 It is a schematic diagram showing the case where the sheet-shaped composite material is arranged to be bent along the molding die in the process 101.

[0066] Figure 7 It is a schematic diagram showing the case where the molding die is bent between the second gate (102) and the sheet-shaped composite material in the process 101.

[0067] Figure 8 It is a schematic diagram showing the case where the second molding die contacts the sheet-shaped composite material to restrict the sheet-shaped composite material.

[0068] Figure 9 It is a schematic diagram showing an example of the cross-section of a molded body produced by the manufacturing method of the present invention.

[0069] Figure 10 It is a schematic diagram showing an example of the cross-section of a molded body at the completion of molding produced by the manufacturing method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0070] The preferred embodiments of the present invention will be described in detail below.

[0071] [Reinforcing portion, laminated injection portion, main body portion]

[0072] In a molded body, a portion formed of a sheet-like composite material is sometimes referred to as a reinforcing portion, a portion formed of an injection molding material that is in a laminated relationship with the above-described reinforcing portion is referred to as a laminated injection portion, and a portion formed of an injection molding material other than the laminated injection portion is referred to as a main body portion. Preferably, the main body portion is larger than the reinforcing portion.

[0073] For example, in Figure 9 a cross-sectional view of the molded body in this embodiment is shown. Figure 9 901 in

[0074] is a reinforcing portion. The portion formed of an injection molding material that is in a laminated relationship with the reinforcing portion 901 is a laminated injection portion 902. The portion formed of an injection molding material other than the laminated injection portion 902 is a main body portion 903.

[0075] In addition, the laminated injection portion 902 is preferably made of a first injection molding material 111 injected from a first gate described later. On the other hand, the main body portion 903 is preferably formed of the injection molding material 111 and a second injection molding material 112 injected from a second gate described later. Figure 9 The volume of the first injection molding material 111 used (the injection amount V1 of the injection molding material) is preferably larger than the volume of the laminated injection portion 902, and the volume of the second injection molding material 112 used (the injection amount V2 of the injection molding material) is preferably smaller than the volume of the main body portion 903. When the volume of the first injection molding material 111 is larger than the volume of the laminated injection portion 902 and the volume of the second injection molding material 112 is smaller than the volume of the main body portion 903, as

[0076] [Sheet-like composite material]

[0077] The sheet-like composite material includes reinforcing fibers and a resin. In the sheet-like composite material, the reinforcing fibers are dispersed in the resin in a plane direction. It should be noted that the composite material in this embodiment is in a sheet form, and sometimes the "sheet-like composite material" is simply referred to as "composite material" for convenience.

[0078] [Reinforcing fibers]

[0079] The reinforcing fibers are preferably at least one selected from carbon fibers, aramid fibers, and glass fibers, and more preferably carbon fibers or glass fibers.

[0080] [Carbon fibers]

[0081] 1. All carbon fibers

[0082] As carbon fibers, polyacrylonitrile (PAN)-based carbon fibers, petroleum / coal pitch-based carbon fibers, rayon-based carbon fibers, cellulose-based carbon fibers, lignin-based carbon fibers, phenol-based carbon fibers, etc. are generally known. In the present embodiment, any of these carbon fibers can be preferably used. Among them, in the present embodiment, considering the excellent tensile strength, PAN-based carbon fibers are preferably used. As the PAN-based carbon fibers, for example, carbon fiber "Tenax" (registered trademark) STS40-24KS (average fiber diameter 7 μm) manufactured by Teijin Limited can be used.

[0083] 2. Sizing agent for carbon fibers

[0084] The carbon fibers may have a sizing agent attached to the surface. When using carbon fibers with a sizing agent attached, the type of the sizing agent can be appropriately selected according to the type of the carbon fibers and the type of the resin used in the composite material, and there is no particular limitation.

[0085] [Glass fibers]

[0086] Among all glass fibers, as long as the glass fibers are generally referred to as glass fibers, any glass fibers can be used. The glass compositions such as A glass, C glass, and E glass specified in JIS R3140:2006 are not particularly limited, and components such as TiO2, SO3, and P2O5 may also be contained according to circumstances. As the glass fibers, for example, glass fiber E-glass RS240QR-483 (count: 2400 g / 1000 m) manufactured by Nitto Boseki Co., Ltd. can be used.

[0087] 2. Sizing agent for glass fibers

[0088] The glass fibers may have a sizing agent attached to the surface. When using glass fibers with a sizing agent attached, the type of the sizing agent can be appropriately selected according to the type of the glass fibers and the type of the resin, and there is no particular limitation. Glass fibers preferably used are those that have been previously treated with a conventionally known coupling agent such as an organosilane compound, an organotitanium compound, an organoborane compound, and an epoxy compound.

[0089] [Dispersion in the in-plane direction]

[0090] The reinforcing fibers contained in the sheet-like composite material are preferably dispersed in the in-plane direction. The dispersion of the reinforcing fibers in the in-plane direction means that the fibers are dispersed in such a way that the fiber axes of the reinforcing fibers face the in-plane direction. The angle formed by the fiber axis of the reinforcing fibers and the in-plane direction is preferably 45° or less.

[0091] 1. The in-plane sheet-like composite material is preferably a plate-like material. The in-plane direction refers to any direction perpendicular to the plate thickness direction of the composite material. The "plane" in the in-plane direction refers to the "plane" perpendicular to the plate thickness direction of the composite material.

[0092] 2. Randomly dispersed in two-dimensional directions

[0093] The reinforcing fibers are preferably randomly dispersed in two-dimensional directions in the in-plane direction of the sheet-like composite material. In the case of compression molding without causing the composite material to flow, the morphology of the reinforcing fibers is substantially maintained before and after molding. Therefore, the reinforcing fibers contained in the reinforcing part after molding the composite material are also preferably randomly dispersed two-dimensionally in the in-plane direction.

[0094] Here, two-dimensional random dispersion means that the reinforcing fibers are not oriented in a specific direction such as one direction in the in-plane direction of the composite material, but are randomly oriented and arranged in the sheet plane in a manner that does not exhibit a specific directionality as a whole. The composite material obtained using such discontinuous fibers with two-dimensional random dispersion is isotropic in-plane and does not have anisotropy.

[0095] It should be noted that the degree of orientation indicating the two-dimensional random dispersion of the reinforcing fibers in the in-plane direction of the composite material is evaluated by obtaining the ratio of the tensile elastic moduli in two mutually orthogonal directions of the composite material. For any direction of the composite material and the direction orthogonal to it, if the ratio (Eδ) obtained by dividing the larger value of the tensile elastic modulus values measured respectively by the smaller value is 5 or less, more preferably 2 or less, and further preferably 1.5 or less, it can be evaluated that the reinforcing fibers are randomly dispersed two-dimensionally. In the case where the reinforcing part formed by the composite material is a curved surface, as a method for evaluating the degree of two-dimensional random dispersion (orientation degree) of the reinforcing fibers in the in-plane direction of the reinforcing part, the reinforcing part can be heated to a temperature above the softening temperature to return to a flat plate shape, and then cured after only taking out the reinforcing part. Then, test pieces are cut out from the reinforcing part that has returned to the flat plate shape, and the tensile elastic moduli in two mutually orthogonal directions of the test pieces are obtained, thereby enabling the evaluation of two-dimensional random dispersion in the reinforcing part.

[0096] 3. Advantages of dispersion in the in-plane direction

[0097] By using a composite material containing reinforcing fibers dispersed in the in-plane direction, even if the composite material flows slightly during molding and there is a deviation in the position where the configuration is completed, the basic mechanical properties will not change significantly. In addition, compared with the case of using continuous fibers such as plain weave fabrics, the shape followability is improved.

[0098] [Fiber length of the reinforcing fibers contained in the sheet-like composite material]

[0099] 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, when manufacturing the composite material by compression molding, the fluidity of the material is not easily reduced, and it is easy to form the reinforcing portion into a desired shape. In addition, when LwA is 1 mm or more, the mechanical strength of the obtained reinforcing portion is not easily reduced, so it is preferred.

[0100] The weight-average fiber length LwA of the reinforcing fibers contained in the composite material does not change before and after molding. Therefore, if the weight-average fiber length of the reinforcing fibers contained in the reinforcing portion is investigated, 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 further 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).

[0101] [Injection molding material]

[0102] The injection molding materials (the first injection molding material 111 and the second injection molding material 112) forming 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 material are preferably the above-mentioned carbon fibers or glass fibers. The fluidity of the injection molding material is higher than that of the composite material.

[0103] [Fiber length of the reinforcing fibers contained in the injection molding material]

[0104] 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-like composite material. Therefore, the injection molding material preferably contains reinforcing fibers with a weight-average fiber length LwB, and LwB < LwA. In the case of LwB < LwA, the mechanical strength of the reinforcing portion formed of the composite material is higher than the mechanical strength of the main body portion (and the laminated injection portion) formed of the injection molding material. Therefore, the molded body can be strengthened by the reinforcing portion.

[0105] The injection molding material is injected into the molding die to mold the main body portion (and the laminated injection portion). When manufacturing the injection molding material, there is a kneading process. In the present embodiment, the kneaded material is called the injection molding material.

[0106] 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 still more preferably 0.1 mm or more. If 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) can be 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 still more preferably less than 1 mm. The weight-average fiber length of the reinforcing fibers is obtained by the following formula (1).

[0107] [Weight-average fiber length Lw]

[0108] Generally, if the fiber length of each reinforcing fiber is set to L i , the weight-average fiber length Lw is obtained by the following formula (1). It should be noted that the unit of the weight-average fiber length Lw is mm.

[0109] [Equation 1]

[0110]

[0111] Here, "I" represents the number of reinforcing fibers measured.

[0112] The extraction of the reinforcing fibers from the reinforcing portion 901 and the main body portion 903 (and the laminated injection portion 902) can be carried out, for example, by performing 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 measured to the unit of 1 mm for 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 laminated injection portion 902) after the above heat treatment using a vernier caliper or the like, and calculated based on formula (1).

[0113] In the case of containing short reinforcing fibers that cannot be measured with a vernier caliper, after removing the resin, the obtained reinforcing fibers can be put into water containing a surfactant and sufficiently stirred by ultrasonic vibration. The dispersion liquid of the reinforcing fibers after stirring can be randomly collected by a measuring spoon to obtain a sample for evaluation, and the length of the reinforcing fibers when the number of fibers is 3000 (I = 3000) can be measured using an image analysis device LuzexAP manufactured by Nireco Corporation. The weight-average fiber length Lw can be obtained in the same manner as the above formula (1) using the measured values L1 to L3000 of the fiber lengths.

[0114] [Volume ratio of reinforcing fibers in sheet composite material and injection molding material]

[0115] For composite materials and injection molding materials, the volume ratio (Vf) of the reinforcing fibers can be determined respectively by the following formula (2).

[0116] Volume ratio (Vf) of the reinforcing fibers = 100 × volume of the reinforcing fibers / (volume of the reinforcing fibers + volume of the resin) Formula (2)

[0117] The volume ratio of the reinforcing fibers contained in the composite material is not particularly limited. The volume ratio (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 still more preferably 25 Vol% or more and 45 Vol% or less.

[0118] In addition, generally speaking, for injection molding materials with higher fluidity than composite materials, in most cases, the fiber volume ratio (Vfb) of the injection molding material is lower than the fiber volume ratio (Vfa) of the composite material, i.e., Vfa > Vfb. The volume ratio Vfb of the 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 still more preferably 10 Vol% or more and 25 Vol%.

[0119] [Analysis of the volume ratio (Vf) of the reinforcing fibers]

[0120] The analysis of the volume ratio of the reinforcing fibers is not limited and can be measured as follows. Cut out a sample from the reinforcing part or the main body part (and the laminated injection part), and burn off the resin in the furnace at 500 °C for 1 hour. Weigh the mass of the specimen before and after the treatment, and thus calculate the mass of the reinforcing fibers and the resin. Then, using the specific gravity of each component, calculate the volume ratio of the reinforcing fibers to the resin. Vf = 100 × volume of the reinforcing fibers / (volume of the reinforcing fibers + volume of the resin)

[0121] [Resin]

[0122] The resin contained in the composite material and the resin contained in the injection molding material can be a thermosetting resin or a thermoplastic resin.

[0123] 1. Thermoplastic resin

[0124] 1.1 General description

[0125] When the resin used is a thermoplastic resin, its type is not particularly limited, and a resin with a desired softening point or melting point can be appropriately selected and used. As the above-mentioned thermoplastic resin, a thermoplastic resin with a softening point in the range of 180 °C to 350 °C is usually used, but it is not limited thereto.

[0126] Examples of the thermoplastic resin include polyolefin resin, polystyrene resin, polyamide resin, polyester resin, polyacetal resin (polyformaldehyde resin), polycarbonate resin, (meth)acrylic resin, polyarylate resin, polyphenylene ether resin, polyimide resin, polyether nitrile resin, phenoxy resin, polyphenylene sulfide resin, polysulfone resin, polyketone resin, polyether ketone resin, thermoplastic polyurethane resin, fluororesin, thermoplastic polybenzimidazole resin, etc.

[0127] The thermoplastic resin used in the sheet composite material and the injection molding material may be only one kind, or two or more kinds. As a method of using two or more kinds of thermoplastic resins in combination, for example, there may be mentioned a method of using thermoplastic resins having different softening points or melting points in combination, a method of using thermoplastic resins having different average molecular weights in combination, etc., but not limited thereto.

[0128] When using a thermoplastic resin, it is more preferable to use a polyolefin resin, and further preferably to use a polypropylene resin.

[0129] 1.2 Resin of sheet composite material and injection molding material

[0130] The resin contained in the composite material is preferably a thermoplastic resin. When the resin contained in the composite material is a thermoplastic resin, the resin contained in the composite material and the injection molding material is more preferably the same kind of thermoplastic resin.

[0131] 2. Thermosetting resin

[0132] The resin contained in the composite material may also be a thermosetting resin. In this case, a sheet molding compound using reinforcing fibers may also be used for the composite material. Since the sheet molding compound has high moldability, even a complex shape can be easily molded. The fluidity and formability of the sheet molding compound are higher than those of continuous fibers, and ribs and protrusions can be easily produced.

[0133] [Other reagents]

[0134] Within the scope not impairing the object of the present invention, the resin used in the composite material and the injection molding material may contain various fibrous or non-fibrous fillers such as organic fibers or inorganic fibers, flame retardants, UV-resistant agents, stabilizers, mold release agents, pigments, softeners, plasticizers, surfactants, and other additives.

[0135] [Preferred fiber combination]

[0136] Preferably, the reinforcing fibers contained in the composite material are glass fibers and / or carbon fibers, and the reinforcing fibers contained in the injection molding material are glass fibers. As the reinforcing fibers contained in the composite material, carbon fibers may be partially used, and glass fibers may be used in the portions other than the portions where carbon fibers are used. For the portions where carbon fibers are used in a part of the composite material, for example, when a hole h is provided in the molded body, it is preferably the portion that becomes the peripheral portion of the hole h.

[0137] [Integral molding]

[0138] The manufacturing method of the molded body of the present embodiment is integral molding using a composite material and an injection molding material. Integral molding means that they are molded continuously without having a seam, rather than molding by joining separate components to each other. Such integral molding can produce a structure by one-time molding, and is preferably achieved by compression molding. Since it is produced by integral molding, different elements can be processed into one element, and the unit price of the elements can be reduced. In addition, the number of assembly processes is reduced, and the costs related to inventory can also be reduced by reducing the number of components.

[0139] [Manufacturing method]

[0140] The manufacturing method of the molded body of the present embodiment is a manufacturing method of integral molding a molded body using a composite material and an injection molding material containing reinforcing fibers dispersed in the in-plane direction and a resin, and includes the following processes 101 to 401.

[0141] Process 101: A process of disposing the above composite material in the cavity of the first molding die.

[0142] Process 201: A process of moving the second molding die toward the above composite material that has been disposed.

[0143] Process 301: A process of injecting the above injection molding material into the molding die from the first gate and the second gate provided in the above first molding die.

[0144] Process 401: A process of pressing the above composite material and the above injection molding material in the molding die to integrally mold the above molded body.

[0145] By integrally molding the composite material and the injection molding material, a molded body with excellent joint strength of the reinforcing portion, the main body portion, and the laminated injection portion can be obtained. In addition, by pressing the composite material and the injection molding material, a molded body with a complex shape having ribs and protrusions can be manufactured.

[0146] [In the case of cold pressing, manufacturing process: Process 001]

[0147] When the resin contained in the composite material and the injection molding material is a thermoplastic resin, cold pressing is preferably used. In the manufacturing method of manufacturing a molded body by cold pressing, before step 101, there is step 001, that is, "Step 001: A step of heating the composite material to a first specified temperature."

[0148] When the composite material is preheated to the first specified temperature, when the thermoplastic resin contained in the composite material is crystalline, the first specified temperature is a temperature above the melting point and below the decomposition temperature of the thermoplastic resin. When the thermoplastic resin contained in the composite material is amorphous, the first specified temperature is a temperature above the glass transition temperature and below the decomposition temperature of the thermoplastic resin.

[0149] In the case of cold pressing, the temperatures of the first molding die and the second molding die are adjusted to a second specified temperature. When the thermoplastic resin contained in the composite material is crystalline, the second specified temperature is a temperature lower than the melting point of the thermoplastic resin. When the thermoplastic resin contained in the composite material is amorphous, the second specified temperature is a temperature lower than the glass transition temperature of the thermoplastic resin.

[0150] In this way, by adjusting the temperature of the composite material and the first molding die, cold pressing can be appropriately performed.

[0151] [Manufacturing method: Step 101]

[0152] Step 101 is a step of disposing the composite material in the cavity of the first molding die.

[0153] In step 101, the cavity area of the first molding die is larger than the area of the disposed composite material. The area of the composite material refers to the area observed along the molding die when the composite material is disposed on the molding die. For example, in Figure 4 shows the state of disposing the composite material 105 along the first molding die 108. The area of the composite material is the area of the composite material 105 that can be observed from Figure 4 301 (eyes) (the area of the surface of the composite material), and does not include the area of the part in contact with the molding die 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 of the composite material, nor the projected area.

[0154] The disposition of the composite material is preferably preformed and disposed in the cavity of the first molding die in a manner along the cavity of the first molding die. The preforming does not need to completely follow the first molding die.

[0155] The area of the configured composite material in this embodiment is smaller than the area of the cavity of the first molding die. Therefore, there is an area in the cavity of the first molding die where the composite material is not configured.

[0156] Preferably, the composite material is fixed in the cavity of the first molding die by a plurality of fixing members. The fixing member can be, for example, a sliding core that forms holes in the molded body. For example, holes can also be provided in the composite material in advance, and the fixing members can be inserted into the holes of the composite material to fix the composite material. Alternatively, the composite material can also be fixed by piercing the composite material with pin-shaped fixing members. In this case, holes do not need to be provided in the composite material.

[0157] The above-mentioned composite material is preferably only configured in the cavity of the first molding die. Compared with the case where the composite material is configured on the outer peripheral edge of the cavity and fixed on the outer peripheral edge, no additional equipment is required, and the molding process does not become complicated.

[0158] [Manufacturing method: Process 201]

[0159] This is a process of moving the second molding die toward the above-mentioned configured composite material. It can be moved until the second molding die contacts the composite material. However, in Process 301, when the injection molding material is put in just before the second molding die contacts the composite material, Process 201 is until the injection molding material is put in.

[0160] [Manufacturing method: Process 301]

[0161] 1. Heating of the injection molding material

[0162] For the injection molding material when it is put into the molding die, preferably, when the thermoplastic resin contained in the injection molding material is crystalline, it is heated to a temperature above the melting point and below the decomposition temperature of the thermoplastic resin, and when the thermoplastic resin is amorphous, it is heated to a temperature above the glass transition temperature and below the decomposition temperature of the thermoplastic resin. The heating is preferably carried out in the kneading process.

[0163] 2. Injection timing of the injection molding material

[0164] The injection molding material is put into the molding die in process 301. The injection timing of the injection molding material can be before the pressure is about to be applied from the second molding die to a part of the composite material, or after the pressure is applied. From the viewpoint of suppressing the position shift of the composite material in the molding die, it is preferable that the second molding die is in contact with at least a part of the composite material, and the injection molding material is injected immediately after the pressure is just applied to the composite material. In order to fill the injection molding material between the first molding die and the composite material, the movement of the second molding die can be temporarily stopped before the molding die is completely closed. The position where the movement of the second molding die is stopped is preferably after the second molding die comes into contact with the composite material.

[0165] 3. Gate position 3.1

[0167] The gate for injecting the injection molding material is provided in the first molding die. More preferably, the gate for injecting the injection molding material is preferably not provided in the movable die but in the fixed die, and more preferably the first molding die is the fixed die.

[0168] For example, in Figure 1 , Figure 2 , in order to inject the first injection molding material 111 and the second injection molding material 112, the gates (101, 102, 103) are provided in the first molding die (108).

[0169] 3.2 First gate

[0170] The first gate is provided in the area where the composite material 105 is arranged. Figure 5 The state immediately after the composite material 105 is arranged in the first molding die 108 is shown. 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 arranged. The first gates (101, 103) as injection gates are provided in this area in advance.

[0171] 3.3 Second gate

[0172] The second gate 102 is provided in the cavity area of the first molding die 108 where the composite material 105 is not arranged. For example, Figure 5 the second gate 102 in is provided at a position in the cavity of the first molding die 108 that does not come into contact with the composite material 105. Based on the arrangement position of the composite material 105, the position of the second gate 102 is determined in advance by reverse deduction.

[0173] 3.4 Injection volume and the set positions of the first gate and the second gate

[0174] In this embodiment, as in Figure 1 , Figure 2As shown, the injection volume of the first injection molding material 111 from the first gate 101 is set as V1, the injection volume of the second injection molding material 112 from the second gate 102 is set as V2, the distance from the first gate to the end of the composite material is set as X1, and the distance from the second gate to the end of the composite material is set as X2.

[0175] In addition, as Figure 5 shown, in the case where there are multiple first gates 101, 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 set as X1. Similarly, in the case where 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 set as X2.

[0176] 3.4.1 X1 and X2

[0177] In Figure 5 are shown examples of X1 and X2 in the present embodiment. X1 is the distance from the first gate (101) to the end P of the composite material (105). More specifically, when looking down at 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) and connecting the first gate 101 and the second gate 102 with a straight line, the distance between the position P where the straight line intersects the end of the composite material 105 and the first gate 101 is X1. Assuming that the composite material 105 is configured as Figure 6 bent along the first molding die 108, it is the distance between the position P and the first gate 101 when measured along the surface distance of the cavity surface of the first molding die 108. If the distance of X1 is relatively short to some extent, the first injection molding material 111 injected from the first gate 101 can quickly expand to a position outside the end of the composite material 105.

[0178] On the other hand, X2 refers to the distance from the second gate (102) to the composite material (105). More specifically, when looking down at the composite material 105, the first gate 101 and the second gate 102 and connecting the first gate 101 and the second gate 102 with a straight line, the distance between the position P where the straight line intersects the end of the composite material 105 and the second gate 102 is X2. Assuming that the cavity surface of the first molding die 108 is bent as Figure 7 shown, it is the distance between the position P and the second gate 102 when measured along the surface distance of the cavity surface of the first molding die 108. If a certain distance of X2 is ensured in advance, the second injection molding material 112 injected from the second gate 102 can stop at a position outside the end of the composite material 105.

[0179] 3.4.2 V1 and V2

[0180] V1 is the injection amount of the first injection molding material 111 injected from the first gates 101 and 103 provided in the area where the composite material 105 is disposed when looking down at the cavity of the molding die.

[0181] V2 is the injection amount of the second injection molding material 112 injected from the second gate 102 provided in an area outside the area where the composite material is disposed when looking down at the cavity of the molding die.

[0182] If the amount of the injection amount 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 is likely to rapidly spread the material into the cavity of the molding die. On the contrary, if the injection amount V1 is small, the speed at which the first injection molding material 111 spreads into the cavity of the molding die becomes slow. If the injection amount V1 becomes small, for example, as shown by the reference numeral 205 in Figure 3B the end of the composite material 105 is more likely to be wrapped between the first injection molding material 111 and the second injection molding material 112.

[0183] When the amount of the injection amount V2 of the second injection molding material 112 injected from the second gate 102 is small, the speed at which the second injection molding material 112 injected from the second gate 102 spreads into the cavity of the molding die becomes slow. On the contrary, if the injection amount V2 is large, the speed at which the second injection molding material 112 spreads into the cavity of the molding die becomes fast. If the injection amount V2 is large, for example, as shown by the reference numeral 205 in Figure 3B the end of the composite material 105 is more likely to be wrapped between the first injection molding material 111 and the second injection molding material 112.

[0184] 3.4.3 V1 / (X1 × volume of the laminated injection part) > V2 / (X2 × volume of the main body part)

[0185] When V1 / (X1 × volume of the laminated injection part) > V2 / (X2 × volume of the main body part) is satisfied, it is possible to appropriately prevent the end of the material (composite material) with low fluidity in the molding die from being wrapped between the injection materials with fluidity. More preferably, V1 / X1 > ((V2 / X2) × 0.5), and further preferably, V1 / X1 > V2 / X2.

[0186] As described above, the larger V1 is and the smaller V2 is, the more difficult it is for the composite material 105 to be clamped 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 clamped by the first injection molding material 111 and the second injection molding material 112.

[0187] For example, in Figure 3A the case where the injection volume V1 of the first injection molding material 111 injected from the first gates 201 and 203 is less than the injection volume V2 of the second injection molding material 112 injected 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, as shown by the reference numeral 205 in Figure 3B , it may cause the end of the composite material 105 to be wrapped by the injection molding material 111 and the injection molding material 112.

[0188] In addition, the larger the volume of the main body portion 903 compared to the laminated injection portion 902, the more difficult it is for the composite material 105 to be clamped by the first injection molding material 111 and the second injection molding material 112. Generally, the injection molding material flows in the direction with a larger cavity space and a smaller shear force generated during flow. The space between the composite material 105 and the second molding die 107 is narrow, and a higher shear force is required when the second injection molding material 112 enters therebetween. On the other hand, when the volume of the main body portion 903 is large, the second injection molding material 112 starts to fill first and fills the larger cavity space for forming the main body portion 903. Since the larger cavity space generates a lower shear force during flow, the main body portion 903 is formed before the injection molding material 2 enters between the composite material and the second molding die. Therefore, even when V2 is large or X2 is short, it is possible to suppress the entry between the composite material 105 and the second molding die 107.

[0189] Moreover, when the size of the laminated injection portion 902 is small, even when V1 is small or X1 is long, the filling is completed earlier with the first injection molding material 111. Thus, before the main body portion 903 is formed by the second injection molding material 112, the laminated injection portion 902 is formed by the first injection molding material 111. At this time, the first injection molding material 111 is likely to reach the end of the composite material 105 earlier than the second injection molding material 112.

[0190] In other words, by satisfying V1 / (X1 × volume of the laminated injection portion) > V2 / (X2 × volume of the main body portion), 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 disposed, thereby avoiding the end of the composite material 105 from being wrapped by the injection molding materials 111 and 112 (for example Figure 3B(reference numeral 205). 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 is generated outside the area where the composite material is disposed after molding is completed. At this time, the flow length ratio X1 of the first injection molding material 111 is longer (for example Figure 2 ). In addition, since the composite material 105 may sometimes move during molding, the position where the composite material 105 is disposed in step 101 does not necessarily coincide with the area where the composite material 105 is disposed after molding is completed. In addition, the composite material 105 is sometimes referred to as the reinforcing part 901 after molding, so the area where the composite material 105 is disposed after molding is completed can be referred to as the area where the reinforcing part 901 is disposed after molding is completed.

[0191] On the contrary, in the case of V1 / (X1×volume of the stacked injection part) < V2 / (X2×volume of the main body part), as Figure 3B shown by reference numeral 205, the end of the composite material 105 is wrapped between the first injection molding material 111 and the second injection molding material 112. In addition, in the present embodiment, it is not necessary to fix the composite material 105 to the outer peripheral part of the cavity of the molding die. This is because, by satisfying V1 / (X1×volume of the stacked injection part) > V2 / (X2×volume of the main body part), a large deviation in the position of the composite material in the molding die can be prevented.

[0192] 3.4.4 Preferred range

[0193] X1 is preferably 10 mm or more and 1000 mm or less, more preferably 30 mm or more and 800 mm or less, further preferably 50 mm or more and 600 mm or less, and still more preferably 80 mm or more and 300 mm or less.

[0194] X2 is preferably 20 mm or more and 1200 mm or less, more preferably 50 mm or more and 1000 mm or less, further preferably 80 mm or more and 800 mm or less, and still more preferably 100 mm or more and 500 mm or less.

[0195] V1 is preferably 25 ml or more and 1200 ml or less, more preferably 50 ml or more and 1000 ml or less, further preferably 100 ml or more and 800 ml or less.

[0196] V2 is preferably 10 ml or more and 1000 ml or less, more preferably 30 ml or more and 800 ml or less, further preferably 80 ml or more and 600 ml or less.

[0197] The volume of the stacked injection part 902 is preferably 10 cm 3Above and 1100 cm 3 Below, more preferably 30 cm 3 Above and 900 cm 3 Below, further preferably 50 cm 3 Above and 700 cm 3 Below.

[0198] The volume of the main body portion 903 is preferably 20 cm 3 Above and 1100 cm 3 Below, more preferably 40 cm 3 Above and 900 cm 3 Below, further preferably 90 cm 3 Above and 700 cm 3 Below.

[0199] The volume of the reinforcing portion 901 is preferably 10 cm 3 Above and 1100 cm 3 Below, more preferably 30 cm 3 Above and 900 cm 3 Below, further preferably 50 cm 3 Above and 700 cm 3 Below.

[0200] 3.5 Generation position of the weld line

[0201] The weld line refers to a part where a linear pattern is confirmed in a molded body obtained by a molding method in which a resin-based material is melted and flowed, and is also called a weld mark or a welded part. The reason for this name is the linear weld mark generated when metal materials are welded to each other.

[0202] 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 preferably occurs outside the region where the composite material 105 is disposed after molding is completed.

[0203] In other words, 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 preferably forms outside the region where the reinforcing portion 901 is disposed after molding is completed. By generating the above-mentioned weld line 109 outside the region where the composite material 105 is disposed after molding is completed, it is possible to prevent the end of the composite material 105 from being enclosed by the injection molding material. 3.6

[0205] In the present embodiment, there may be a plurality of first gates, and similarly, there may also be a plurality of second gates. For example, Figure 1 The gate marked with reference numeral 103 is a gate in the region where the composite material 105 is disposed, and thus corresponds to the first gate in the present embodiment.

[0206] In the case where there are a plurality of first gates and a plurality of second gates, it is sufficient that at least one pair of the first gate and the second gate satisfies V1 / (X1×volume of the laminated injection portion)>V2 / (X2×volume of the main body portion). In the case where there are a plurality of first gates and a plurality of second gates, when the total amount of the first injection molding material injected from all the first gates is set as V1 and the total amount of the first injection molding material injected from all the second gates is set as V2, V1, V2, X1, and X2 may also satisfy V1 / (X1×volume of the laminated injection portion)>V2 / (X2×volume of the main body portion). Here, when the first gate closest to the end of the composite material and the second gate 102 closest to the end of the composite material are connected by a straight line, and the position where the straight line intersects the end of the composite material is set 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.

[0207] 4. Entry of the injection molding material

[0208] In the present embodiment, at the moment of molding completion, the injection molding material does not enter between the composite material and the second molding die. As a result, the appearance design surface formed by the second molding die becomes good. If the injection molding material enters between the composite material and the second molding die, the appearance design surface of the composite material is blocked, and a beautiful appearance design surface cannot be maintained. Furthermore, by preventing the injection molding material from entering between the composite material and the second molding die, the reinforcing portion can directly exhibit the mechanical strength of the composite material, and the physical properties of the reinforcing fibers randomly dispersed in the two-dimensional direction included in the reinforcing portion can be exhibited.

[0209] It should be noted that the entry of the injection molding material may occur in process 301 or process 401, but in the present embodiment, in either process 301 or process 401, the injection molding material does not enter between the composite material and the second molding die.

[0210] 5. Interception of the injection molding material

[0211] In process 301, it is preferable to intercept the injection molding material by bringing the second molding die into contact with the composite material. For example, as Figure 8As shown, when the composite material 105 is pressed by the upper mold 107 (the second molding die), the upper mold 107 contacts the composite material 105, thereby being able to intercept the second injection molding material 112. In this case, if the cavity space in the larger molding die expands in the direction indicated by the arrow 802 of Figure 8 it is preferred because it is more difficult for the second injection molding material 112 to enter between the upper mold 107 and the composite material 105.

[0212] [Flow rate of injection molding material]

[0213] 1. Control of flow rate

[0214] The method for controlling the flow rate of the injection molding material is not particularly limited. If the mold closing time during molding is shortened or the mold closing distance is shortened, the flow rate of the injection molding material becomes faster. In addition, the flow rate of the injection molding material also depends on the input amount of the injection molding material.

[0215] 2. Preferred flow rate

[0216] The flow rate of the injection molding material is not particularly limited. It is preferred 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 speed is 200 mm / sec or less.

[0217] If the flow time of the first injection molding material 111 is 5 seconds or less, it is easy to fill the cavity with the first injection molding material 111 before the second molding die 107 contacts the first injection molding material 111. Therefore, the first injection molding material 111 does not cool and solidify prematurely, and thus the surface designability of the obtained molded body becomes good. More preferably, the flow time of the first injection molding material 111 is 4 seconds or less, and further preferably, the flow time of the first injection molding material 111 is 3 seconds or less.

[0218] On the other hand, if the maximum flow speed of the first injection molding material 111 injected from the first gate is 200 mm / sec or less, it is possible to prevent the arranged composite material 105 from being washed away, broken, 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 molding die 107 and the composite material 105 depending on the flow rate. By making the maximum flow speed of the first injection molding material 111 200 mm / sec or less, the shear force can be suppressed, thereby preventing the composite material 105 from being torn.

[0219] The maximum flow velocity of the more preferred first injection molding material 111 is 10 mm / sec or more and 200 mm / sec or less, and the maximum flow velocity of the further preferred first injection molding material 111 is 30 mm / sec or more and 150 mm / sec or less.

[0220] Preferably, the flow time of the second injection molding material injected from the second gate is longer than the flow time of the first injection molding material.

[0221] In addition, in general injection molding, the injection time in injection molding is 2 seconds or less, preferably 1 second or less. According to the shape of the molded body, the injection rate (cc / sec) is mostly adjusted so as to complete filling within 1 second. The flow velocity described in this embodiment is not the cylinder moving velocity, but the moving velocity of the resin in the molding die.

[0222] [Injection site of injection molding material]

[0223] The injection molding material 111 injected from the first gate 101 is preferably filled between the first molding die 108 and the composite material 105. When filling the injection molding material 111 into the molding die, by pressing the composite material 105 against the cavity surface of the second molding die 107 for pressing, the position shift of the composite material 105 can be suppressed. In Figure 1 shows the case where the composite material 105 is pressed by the second molding die 107.

[0224] [Manufacturing method: Process 401]

[0225] 1. The composite material and the injection molding material are integrally molded by pressing with the first molding die and the second molding die. There is no particular limitation on the molding pressure, and it is preferably less than 20 MPa, more preferably 10 MPa or less. Thus, when pressing the composite material and the injection molding material, the injection molding material with higher fluidity than the composite material flows in the molding die.

[0226] Then, the second molding die is moved in a direction away from the first molding die, and the molded body is taken out from the first molding die. Through the above, the molded body is completed.

[0227] [Manufacturing method: Molding die]

[0228] The first molding die and the second molding die in this embodiment are preferably a pair of male and female molding dies. When using the first molding die and the second molding die, they can both be movable dies, or either one can be a movable die and the other can be a fixed die. For example, when the first molding die is a fixed die, the second molding die can be a movable die. Additionally, depending on the type of molding die, there are also cases where the fixed die moves. Assuming the fixed die moves, the molding die with a relatively smaller moving distance is regarded as the fixed die, and the molding die with a relatively larger moving distance is regarded as the movable die.

[0229] Alternatively, it can also be a pair of male and female upper and lower dies where the first molding die is the lower die and the second molding die is the upper die. In this case, it can also be opened and closed by moving the second molding die up and down towards the first molding die. It can also be a molding die that is opened and closed by moving at least one of the first molding die and the second molding die in the horizontal direction.

[0230] Examples

[0231] Hereinafter, the present invention will be specifically described using examples, but the present invention is not limited to these examples.

[0232] 1. Materials

[0233] 1.1 Polypropylene resin

[0234] · Resin for composite materials: Novatec PP BC03C manufactured by Nippon Polypro Co., Ltd.

[0235] · Fiber-reinforced resin for injection molding materials: Mostron L-4070P manufactured by Prime Polymer Co., Ltd.

[0236] (The weight ratio of glass fiber is 40%)

[0237] 1.2 Glass fiber

[0238] Prepare a product with a sizing agent attached to E-glass RS240QR-483 manufactured by Nitto Boseki Co., Ltd. (Sometimes simply recorded as GF).

[0239] 2. Evaluation method

[0240] 2.1 Analysis of the volume ratio of reinforcing fiber (Vf)

[0241] A molded article is cut out from a region made of a composite material or a region made of an injection-molded material, and the resin is burned off in a furnace at 500 °C for 1 hour. The mass of the specimen before and after the treatment is weighed, and the mass of the reinforcing fiber and the resin is calculated therefrom. Then, using the specific gravity of each component, the volume ratio of the reinforcing fiber to the resin is calculated. Volume ratio of reinforcing fiber (Vf) = 100 × volume of reinforcing fiber / (volume of reinforcing fiber + volume of resin) Equation (2)

[0242] 2.2 Analysis of the weight-average fiber length The measurement of the weight-average fiber length of the reinforcing fiber contained in the molded article is carried out by previously removing the resin in a furnace at 500 °C for about 1 hour.

[0243] 2.2.1 After removing the resin from the part formed of the composite material taken out from the reinforcing fiber molded article contained in the composite material, the lengths of 100 randomly extracted glass fibers are measured to the unit of 1 mm with a vernier caliper and recorded. From the lengths of all the glass fibers measured (Li, where i is an integer from 1 to 100), the weight-average fiber length (LwA) is obtained by the above formula (1).

[0244] 2.2.2 Reinforcing fiber contained in the injection-molded material

[0245] The part formed of the injection-molded material is taken out from the molded article and the resin is removed. Then, the obtained reinforcing fiber is put into water containing a surfactant and stirred sufficiently by ultrasonic vibration. An evaluation sample is obtained by randomly collecting the stirred dispersion with a measuring spoon, and the length when the number of fibers is 3000 is measured using the image analysis device Luzex AP manufactured by Nireco Corporation. Using the measured value of the fiber length, the weight-average fiber length Lw is obtained in the same manner as the above formula (1).

[0246] [Example 1]

[0247] (1) Preparation of the composite material

[0248] As the glass fiber, the glass fiber E-glass RS240QR-483 manufactured by Nitto Boseki Co., Ltd. is cut and used as the glass fiber with a fiber length of 20 mm. As the resin, Novatec PPBC03C manufactured by Japan Polypropylene Corporation is used, and a composite composition of glass fiber with two-dimensional random orientation and polypropylene resin is produced based on the method described in U.S. Patent No. 10006677. The obtained composite composition is heated with a pressing device heated to 250 °C at 2.0 MPa for 5 minutes to form a flat composite material with an average thickness of 3 mm, a length of 300 mm, and a width of 500 mm. The fiber volume ratio (Vf) is 35%.

[0249] (2) Preparation of the molding die

[0250] Prepare the upper and lower forming dies. Use the lower forming die as the first forming die and the upper forming die as the second forming die. The size of the cavity of the forming die is a rectangular shape (flat plate) of 300 mm × 806 mm. Set one first gate and one second gate respectively. The designed volumes of the reinforcing part, the laminated injection part, and the main body part are shown in Table 1.

[0251] (3) Manufacturing of the formed body

[0252] After drying the composite material in a hot air dryer at 120 °C for 4 hours, use an infrared heater to raise the temperature to 220 °C, and place the composite material 105 in the lower forming die 108 as shown in Figure 5 . More specifically, place the composite material 105 with a length of 300 mm and a width of 500 mm aligned with the end of the flat plate-shaped forming die cavity with a length of 300 × width of 806 mm.

[0253] When connecting the first gate 201 and the second gate 202 with a straight line and setting the position where the ends intersect as P, set the distance between position P and the first gate 201 as X1, and the distance between position P and the second gate 202 as X2. The distances of X1 and X2 are designed as recorded in Table 1.

[0254] Set the temperature of the forming die to 50 °C, close the forming die, confirm through a pressure gauge that pressure starts to be applied to a part of the composite material 105, then use Mostron L-4070P manufactured by Prime Polymer Co., Ltd., and set the injection amounts V1 and V2 of injection molding material 1 and injection molding material 2 as shown in Table 1 for injection. In addition, set the heating temperature of the injection molding material to 240 °C.

[0255] Then, apply pressure at a pressing pressure of 20 MPa for 1 minute to press the composite material 105, injection molding material 1, and injection molding material 2 simultaneously to manufacture the formed body.

[0256] (4) Observation of the formed body

[0257] Observe the clamping of the ends of the composite material by injection molding material 1 and injection molding material 2 and the misalignment of the arrangement of the composite material.

[0258] When the forming is completed, as shown in Figure 10 , a reinforcing part 1001, a main body part 1003, and a laminated injection part 1002 are formed. In addition, the position of the weld line formed by injection molding material 1 and injection molding material 2 is 1004.

[0259] The ends of the composite material 1001 are not clamped between injection molding material 1 and injection molding material 2. In addition, no misalignment in the arrangement of the composite material 1001 is found.

[0260] Show the results in Table 1.

[0261] It can be seen that the volume of the main body portion 1003 is greater than the injection amount V2 of the injection molding material 2, and the main body portion 1003 is formed by the injection molding material 1 and the injection molding material 2.

[0262] [Example 2]

[0263] Except for changing the size of the composite material, the injection amounts of the injection molding material 1 and the injection molding material 2, and the distance of X2 as shown in Table 1, the molded body was produced in the same manner as in Example 1.

[0264] The end portion of the composite material 1001 was not sandwiched between the injection molding material 1 and the injection molding material 2. In addition, no misalignment of the arrangement of the composite material 1001 was found.

[0265] The results are shown in Table 1.

[0266] [Example 3]

[0267] By shortening the mold clamping time, the flow rate was made faster as recorded in Table 1. Except for this, the molded body was produced in the same manner as in Example 1.

[0268] The end portion of the composite material 1001 was not sandwiched between the injection molding material 1 and the injection molding material 2. Slight misalignment was observed in the arrangement of the composite material 1001.

[0269] The results are shown in Table 1.

[0270] [Comparative Example 1]

[0271] Except for changing the injection amount of the injection molding material 1, the injection amount of the injection molding material 2, the distance of X1, and the distance of X2 as shown in Table 1, the molded body was produced in the same manner as in Example 1. The results are shown in Table 1. Since the distance of X1 is long and the distance of X2 is short, the end portion of the composite material is clamped by the injection molding material 1 and the injection molding material 2. No misalignment of the arrangement of the composite material 1001 was found.

[0272] The results are shown in Table 1.

[0273] [Table 1]

[0274]

Claims

1. A method for manufacturing a molded body, characterized in that: it is a method for manufacturing a molded body by integrally molding a sheet 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 processes 101 to 401: Process 101: A process of arranging the sheet composite material in the cavity of the first molding die; Process 201: A process of moving the second molding die toward the arranged sheet composite material; Process 301: A process of injecting the injection molding material into the molding die from a first gate and a second gate provided in the first molding die; Process 401: A process of pressing the sheet composite material and the injection molding material in the molding die to integrally mold the molded body, wherein, (a) in Process 101, the cavity area of the first molding die is larger than the area of the arranged sheet composite material, (b) the position of the first gate is located in the area where the sheet composite material is arranged in Process 301, and the position of the second gate is located in the area where the sheet composite material is not arranged in Process 301, (c) when molding is completed, the injection molding material does not enter between the sheet composite material and the second molding die.

2. The method for manufacturing a molded body 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. The method for manufacturing a molded body according to any one of claims 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 is generated outside the area where the sheet composite material is arranged after molding is completed.

4. The method for manufacturing a molded body according to any one of claims 1 to 3, wherein: in the manufactured molded body, the part formed by the sheet composite material is used as a reinforcing part, the part formed by the injection molding material in a laminated relationship with the reinforcing part is used as a laminated injection part, and the part formed by the injection molding material other than the laminated injection part is used as a main body part, in Process 301, when the injection amount of the first injection molding material injected from the first gate is set as V1, the injection amount of the second injection molding material injected from the second gate is set as V2, the distance from the first gate to the end of the sheet composite material is set as X1, and the distance from the second gate to the end of the sheet composite material is set as X2, it satisfies V1 / (X1 × volume of the laminated injection part) > V2 / (X2 × volume of the main body part).

5. The method for manufacturing a molded body according to claim 4, wherein: when the first gate and the second gate are connected by a straight line and the position where this straight line intersects the end of the sheet composite material is set as P, X1 is the distance between position P and the first gate, X2 is the distance between position P and the second gate.

6. The manufacturing method of the molded body according to any one of claims 3 to 5, wherein, the first injection molding material reaches the end of the sheet-like composite material before the second injection molding material.

7. The manufacturing method of the 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. The manufacturing method of the molded body according to any one of claims 1 to 7, wherein, in step 301, the second molding die contacts the sheet-like composite material to intercept the injection molding material.

9. The manufacturing method of the molded body according to any one of claims 1 to 8, wherein, in step 101, the sheet-like composite material is disposed only in the cavity of the first molding die.

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