JP5749587B2 - Lightweight molded body having an upright part and method for producing the same - Google Patents

Description

  The present invention relates to a lightweight molded article made of a fiber-reinforced composite material containing reinforcing fibers and a thermoplastic resin, and having an upright portion extending in a longitudinal direction with respect to a horizontal portion such as a rib and / or a boss. Furthermore, it is related with the molded object preferably used for uses, such as a housing | casing for electrical / electronic devices, parts for motor vehicles, parts for medical devices, aircraft parts, building materials, and general industrial parts. Furthermore, it is related with the manufacturing method of this molded object.

  In recent years, there has been an increasing demand for weight reduction in various fields such as electrical and electronic equipment, automobiles, medical equipment, aircraft, building materials, and general industrial parts. It has come to be required. As such a thin-walled and highly rigid housing or member, a molded body obtained by press-working a rolled plate of an aluminum alloy or a magnesium alloy, or a molded body formed by die-cast molding has been used, and glass fiber or carbon is used. A molded body in which a fiber-reinforced composite material filled with fibers is injection-molded or a molded body in which a thermoplastic resin is integrated with a fiber-reinforced composite material plate by injection molding has been used.

  Aluminum alloys and magnesium alloys are excellent in strength and rigidity, but have limited shape shaping properties, and it is difficult to form a complex shape by itself. In addition, metal members (especially magnesium alloys) have a problem that the corrosion resistance is inferior, and the surface is corroded by moisture or salt contained in the moisture in the atmosphere or the user's sweat, resulting in a problem of poor appearance. Therefore, Patent Document 1 proposes a method of manufacturing a housing having a covering step of covering the entire member made of a magnesium alloy with a resin layer and a forming step of integrally forming the member and a resin component. This makes it possible to form a complicated shape and impart corrosion resistance, but the process is complicated and the specific strength of aluminum alloy, magnesium alloy, and resin is high for iron, but will be described later. Since it is lower than the fiber reinforced composite material, there is a limit to the weight reduction that can be achieved.

  The fiber reinforced composite material is excellent in specific strength, specific rigidity, and excellent in corrosion resistance. Therefore, the fiber reinforced composite material is widely used in the above-mentioned applications. In particular, molded products made by injection molding of fiber reinforced composite materials filled with glass fiber or carbon fiber are widely used due to their high degree of freedom in shape and high productivity, but the fiber length remaining in the molded product is shortened. Therefore, problems remain in applications that require high strength and rigidity. On the other hand, fiber reinforced composite materials reinforced with continuous fibers are particularly excellent in specific strength and specific rigidity, and thus have been used mainly for applications that require high strength and rigidity. However, the degree of freedom in shape is low as compared with resin and fiber-reinforced composite materials by injection molding, and it has been difficult to form a complex shape alone. In addition, since it is manufactured by laminating a plurality of reinforcing fibers in a woven form, there is a problem that productivity is low. Patent Document 2 proposes a composite molded product in which a resin member is bonded to the outer edge of a plate-like member made of a sheet containing reinforcing fibers, particularly continuous fibers. As a result, it is possible to realize a molded product having a complicated shape, but it is difficult to say that productivity is high because it is manufactured through a plurality of processes. In addition, a fiber-reinforced composite material using continuous fibers is usually obtained by heating and pressurizing a material called a prepreg in which a reinforcing fiber base is impregnated with a thermosetting resin for 2 hours or more using an autoclave. . In recent years, an RTM molding method in which a thermosetting resin is poured after a reinforcing fiber base not impregnated with resin is set in a mold has been proposed, and the molding time has been greatly reduced. However, even when the RTM molding method is used, it takes 10 minutes or more to mold one part, and productivity is not improved.

  Therefore, a fiber reinforced composite material using a thermoplastic resin as a matrix instead of a conventional thermosetting resin has attracted attention. However, the thermoplastic resin generally has a higher viscosity at the molding temperature than the thermosetting resin, and therefore, it takes a longer time to impregnate the fiber base material with the resin, resulting in a longer tact until molding. There was a problem.

  As a technique for solving these problems, a technique called thermoplastic stamping molding (TP-SMC) has been proposed. This is because the chopped fiber pre-impregnated with thermoplastic resin is heated to a melting point or flowable temperature or more, and after this is put into a part of the mold, the mold is immediately closed, and the fiber and resin in the mold. This is a molding method in which the product shape is obtained by allowing the product to flow, and then cooled and molded. In this method, molding can be performed in a short time of about 1 minute by using a fiber impregnated with a resin in advance. There are Patent Documents 3 and 4 relating to a method of manufacturing a chopped fiber bundle and a molding material, and these are methods for forming a molding material called SMC or a stampable sheet. In such thermoplastic stamping molding, In order to flow the fiber and the resin, there are problems such that a thin-walled one cannot be made, fiber orientation is disturbed, and control is difficult.

JP 2010-147376 A JP 2010-141804 A JP 2009-114611 A JP 2009-114612 A

  An object of the present invention is a composite material composed of reinforcing fibers and a thermoplastic resin, and has a raised portion extending in a vertical direction with respect to a horizontal portion, such as a rib or a boss, and has a complicated three-dimensional shape It is providing the molded object which has. Further, another object of the present invention is to provide a molded body that can maintain the isotropy of fibers even in the upright portion, and can maintain a constant fiber length and fiber content at each portion. It is a further object of the present invention to provide a method for producing a molded body that can be molded into a complicated shape with good shape followability, can be molded in a short time, and does not require trimming into a product shape.

  The present inventors use a random mat composed of a thermoplastic fiber and a random reinforcing fiber including a fiber bundle that satisfies a specific opening condition, and press-molds the mold shape with a low charge, such as a rib or a boss. It has been found that a molded body having an upright portion extending in the vertical direction with respect to the horizontal portion and maintaining the isotropy of the fiber even when having a complicated three-dimensional shape can be provided.

That is, the present invention provides for a random mat composed of a reinforcing fiber and a thermoplastic resin having an average fiber length of 10 to 100 mm, cormorants row impregnation-molding comprises the following steps A-1) ~A-3) , the fibers It is a manufacturing method of the molded object which has an upright part extended to the vertical direction with respect to the horizontal part which consists of a reinforced composite material.
A-1) When the thermoplastic resin is crystalline, the random mat is heated above the melting point and below the decomposition temperature, and when amorphous, it is heated above the glass transition temperature and below the decomposition temperature, and pressurized to reinforce the thermoplastic resin. Step A-2) Obtaining a prepreg by impregnating the bundle The temperature of the prepreg obtained in A-1) is adjusted below the melting point when the thermoplastic resin is crystalline, and below the glass transition temperature when the thermoplastic resin is amorphous. Step A-3) in which the charging rate is 5 to 100% or less represented by the following formula (3) and pressurization is performed on the mold, and when the thermoplastic resin is crystalline, the melting point or less is amorphous. as engineering to complete the molding by adjusting the mold temperature to below the glass transition temperature in the case of
Charge rate (%) = 100 × base material area (mm ² ) / mold cavity projected area (mm ² ) (3)
(Here, the substrate area is the projected area in the extraction direction of all the arranged random mats or prepregs, and the mold cavity projected area is the projected area in the extraction direction.)
The random mat has reinforcing fiber bundles (A) in which the reinforcing fibers are oriented substantially two-dimensionally at a basis weight of 25 to 3000 g / m ² and are composed of the number of critical single yarns or more defined by the formula (1). ), The ratio of the mat to the total amount of fibers is 30 Vol% or more and less than 90 Vol%, and the average number of fibers (N) in the reinforcing fiber bundle (A) satisfies the following formula (2).

Critical number of single yarns = 600 / D (1)
0.7 × 10 ⁴ / D ² <N <6 × 10 ⁴ / D ² (2)
(Here, D is the average fiber diameter (μm) of the reinforcing fibers)
Furthermore, the present invention comprises a fiber reinforced composite material of 50 to 1000 parts by weight of a thermoplastic resin with respect to 100 parts by weight of a reinforcing fiber in which discontinuous reinforcing fibers are present in a random orientation in the thermoplastic resin. A molded body having an upright portion extending in the longitudinal direction, wherein the length of the reinforcing fiber in the upright portion is 10 to 100 mm, and the fiber volume content (Vf) is 5 to 80%.

  According to the present invention, there is provided a molded body having an upright portion extending in a vertical direction with respect to a horizontal portion such as a rib or a boss, and maintaining the isotropy of the fiber even when having a complicated three-dimensional shape. can do. According to the present invention, it is possible to provide a molded product having a complicated three-dimensional shape that is thin, lightweight, highly rigid, excellent in design. According to the present invention, it is possible to provide a molded body capable of maintaining a constant fiber length and fiber content at each part.

Further, according to the present invention, it is possible to obtain a molded body with a good shape following even to a complicated shape, and it is possible to manufacture the molded body with high productivity. In addition, the product shape can be molded using the minimum necessary material, and the waste material can be significantly reduced due to the elimination of the trimming process, and the costs associated therewith can be reduced.
According to the present invention, a casing for electric / electronic equipment, a part for automobile, and a part for general industry can be preferably provided.

The perspective view of one Embodiment of this invention 3 side view (sectional view) of one embodiment of the present invention

Hereinafter, embodiments of the present invention will be described in order, but the present invention is not limited thereto.
In the present invention, a random mat composed of a reinforcing fiber having an average fiber length of 10 to 100 mm and a thermoplastic resin is impregnated or molded including the following steps A-1) to A-3), or a step B It is a manufacturing method of the molded object which has an upright part extended in the vertical direction with respect to the horizontal part which consists of a fiber reinforced composite material which impregnates-shaping | molding including -1)-B-4).
A-1) When the thermoplastic resin is crystalline, the random mat is heated above the melting point and below the decomposition temperature, and when amorphous, it is heated above the glass transition temperature and below the decomposition temperature, and pressurized to reinforce the thermoplastic resin. Step A-2) Obtaining Prepreg by Impregnation into Bundle The temperature of the prepreg obtained in A-1) is adjusted to below the melting point when the thermoplastic resin is crystalline, and below the glass transition temperature when amorphous. Step A-3) in which the charging rate is 5 to 100% or less represented by the following formula (3) and pressurization is performed on the mold, and when the thermoplastic resin is crystalline, the melting point or less is amorphous. In the case of step B-1, the molding is completed by adjusting the mold temperature to be equal to or lower than the glass transition temperature. B-1) The mold is such that the random mat has a charge rate of 5 to 100% or less represented by the following formula (3). Step B-2) Place the mold on the thermoplastic resin In the case of the property of the thermoplastic resin up to a temperature not lower than the thermal decomposition temperature, and in the case of an amorphous material, the pressure is increased while raising the temperature to a temperature higher than the glass transition temperature of the thermoplastic resin and lower than the thermal decomposition temperature (first Pressing process)
B-3) A step of pressurizing so that the pressure in the final step is 1.2 to 100 times the pressure in the first press step (second press step).
B-4) Step of completing molding by adjusting the mold temperature to below the melting point when the thermoplastic resin is crystalline or below the glass transition temperature when amorphous, the charge rate (%) = 100 × base material Area (mm ² ) / Mold cavity projected area (mm ² ) (3) (Here, the substrate area is the projected area of all the random mats or prepregs that are placed in the pulling direction. Is the projected area in the removal direction)
The random mat has reinforcing fiber bundles (A) in which the reinforcing fibers are oriented substantially two-dimensionally at a basis weight of 25 to 3000 g / m ² and are composed of the number of critical single yarns or more defined by the formula (1). ), The ratio of the mat to the total amount of fibers is 30 Vol% or more and less than 90 Vol%, and the average number of fibers (N) in the reinforcing fiber bundle (A) satisfies the following formula (2).

Critical number of single yarns = 600 / D (1)
0.7 × 10 ⁴ / D ² <N <6 × 10 ⁴ / D ² (2)
(Here, D is the average fiber diameter (μm) of the reinforcing fibers)

[Molded body with raised part]
The molded body in the present invention is made of a fiber-reinforced composite material containing reinforcing fibers and a thermoplastic resin, and has a raised portion extending in the vertical direction with respect to the horizontal portion. The horizontal portion refers to a portion that is substantially planar and serves as the foundation of the upright portion, and examples include a ceiling portion or a bottom wall portion of a housing or a panel-like member.

[Horizontal part]
In the molded body, the horizontal portion refers to a portion that is substantially planar and serves as the foundation of the raised portion, and is a portion that serves as the foundation of the raised portion. Upright portions such as bosses and ribs can be freely arranged on one side or both sides with respect to the horizontal portion. The horizontal portion is substantially planar, and a ceiling portion or a bottom wall portion of a housing or a panel-like member is an example. The horizontal portion does not have to be completely planar, and may have partial unevenness and beads. The height and width of the unevenness and the beads are not particularly limited, but the height is preferably 0.5 to 10 times the base horizontal plate thickness. You may have a through-hole for ventilation, bolt fastening, wiring, etc. In this case, a hole may be opened using a shear or the like in the mold at the same time as forming the molded body, or may be opened by drilling, punching, cutting, or the like as post-processing.

  The plate thickness of the horizontal portion is not particularly limited, but 0.2 to 10 mm is preferably used, and 1 to 3 mm is more preferably used. The plate thickness of the horizontal portion does not need to be uniform, and can be locally increased or decreased. In this case, although there is no restriction | limiting in particular in the increase / decrease width | variety of board thickness, 30 to 300% of the horizontal part board thickness used as a foundation is used preferably, and 50 to 200% is used more preferably. The plate thickness can be changed stepwise, and can be continuously changed with a taper or a curvature, but it is preferably changed continuously from the viewpoint of avoiding stress concentration. The molded body in the present invention can be thin.

[Upper part]
In the molded body of the present invention, the upright portion refers to a portion extending in the longitudinal direction with respect to the horizontal portion described above, and examples of the side walls, ribs, bosses, mounts, and hinges of the housing or panel-like member are given. It is done. The height of the upright portion is not particularly limited, but 1 to 300 mm is preferably used, and 5 to 100 mm is more preferably used. The height of the upright portion does not need to be uniform and can be increased or decreased locally. There is no restriction | limiting in particular in the increase / decrease width | variety of standing | upper part height, 10 to 90% of maximum height is used preferably, and 20 to 80% is used more preferably. There is no restriction | limiting in particular in the plate | board thickness of an upright part, It may be the same as a horizontal part, and may differ. Since the upright portion is often required to have a more complicated shape than the horizontal portion, the plate thickness of the upright portion is preferably 0.2 to 100 mm, and more preferably 1 to 50 mm. The plate thickness of the upright portion does not need to be uniform, and can be locally increased or decreased. In this case, although there is no restriction | limiting in particular in the increase / decrease width, 20 to 500% of the standup board thickness used as a foundation is used preferably, and 50 to 200% is used more preferably. The plate thickness can be changed stepwise, and can be continuously changed with a taper or a curvature, but it is preferably changed continuously from the viewpoint of avoiding stress concentration.

  The upright portion extends in the vertical direction at an arbitrary angle from the horizontal portion of the molded body, and the rising angle from the horizontal portion is preferably 30 to 90 degrees, and more preferably 40 to 85 degrees. If the angle from the horizontal portion of the upright portion is smaller than 30 degrees, it is advantageous for releasing from the mold, but more material is required. Moreover, it is also possible to add arbitrary chamfering and curvature to the upright part to such an extent that the intention of the present invention is not impaired. Although there is no restriction | limiting in particular in the dimension of a chamfer or curvature, C0.2-10mm is preferable in the case of a chamfer, and R0.2-10mm is preferable in the case of a curvature. Moreover, it is preferable to provide an angle for ensuring the draft angle of the mold within the range where the intention of the present invention is not impaired. The draft angle of the mold is preferably 1 to 45 degrees, more preferably 5 to 10 degrees. The upright portion may have partial unevenness and beads, but in this case, it should be noted that the draft angle of the mold can be secured.

  Ribs are used to increase the strength and rigidity of molded products without increasing the thickness of the molded product, for example, the edges and side walls of electronic and electrical equipment casings, or to warp or twist the molded product with a wide flat surface. This refers to a projecting reinforcing portion applied for the purpose of preventing or reducing deformation. The boss is used to reinforce a part of the molded body, such as to reinforce the periphery of the hole in the molded body, the fitting allowance when combined with other molded bodies or parts, and the purpose of stabilizing the sitting of the molded body. The protrusion part to provide is pointed out. Although what was specifically disclosed in the Example of this invention is a molded object which has a rib and / or a boss | hub part as an upright part, this invention is not limited to this.

  When the upright portion is a rib, the shape, length, and height of the rib are not particularly limited, and can be appropriately set according to the purpose. For example, in the case of reinforcing the edge or the side wall of the molded body, it is installed in a shape such as a rectangular parallelepiped or a triangular prism at a portion to be reinforced, with a length or height of several mm to several hundred mm. The height is usually preferably 1 to 300 mm, more preferably 5 to 100 mm. If the height is too low, it may be difficult to obtain a reinforcing effect. Further, in order to prevent warping or twisting of the molded body, a continuous rib from one end to the other end of the molded body may be provided. In this case, the height may be constant or may be increased or decreased along the way. The increase / decrease width when increasing / decreasing is preferably 10 to 90% of the maximum height, and more preferably 20 to 80%. There is no restriction | limiting in particular in the thickness of a rib, It may be the same as a horizontal part, and may differ. Since the rib has a more complicated shape than the horizontal portion, the thickness is preferably 0.2 to 100 mm, and more preferably 1 to 50 mm. If the thickness is less than 0.2 mm, a sufficient reinforcing effect may not be exhibited. On the contrary, if it is thicker than 50 mm, it is not preferable in terms of economy and weight reduction. The rib thickness need not be uniform, and can be locally increased or decreased. In this case, although there is no restriction | limiting in particular in the increase / decrease width, 20 to 500% of the base thickness is preferable, and 50 to 200% is more preferable. The thickness can be changed in stages, and can be continuously changed with a taper or curvature, but from the viewpoint of avoiding stress concentration when a load is applied. It is preferable to change. The shape, length, height, and thickness of the rib influence the reinforcement and deformation prevention of the molded body, respectively. The rib is larger, longer, taller, and thicker, and the reinforcing effect is higher. However, doing so is disadvantageous in terms of economy and weight reduction because more materials are required. Therefore, the shape and each size are set in a well-balanced manner according to the required reinforcement and deformation prevention level. Further, the rib may have a through-hole for ventilation, etc., and may be opened with a shear or the like in the mold at the time of molding, and may be opened by drilling, punching or cutting as post-processing. May be.

  When the upright portion is a boss, the shape of the boss is not particularly limited, and any shape such as a prism or a cylinder may be used, but a cylinder is more preferable in terms of reinforcing effect. The height is preferably 0.1 to 300 mm, more preferably 0.2 to 100 mm, depending on the size of the molded body. When the height is lower than 0.1 mm, it is difficult to obtain a reinforcing effect. When the height is higher than 300 mm, many materials are required, which is disadvantageous in terms of economy and weight reduction. The thickness is appropriately set according to the target reinforcement level, and may be the same as or different from the horizontal portion. Since the boss has a more complicated shape than the horizontal part, when the purpose of installing the boss is to stabilize the sitting of the molded body, the thickness is preferably 0.5 to 100 mm, preferably 1 to 50 mm. Is more preferable. Moreover, when reinforcing the hole which passes a screw | thread or a shaft, it is set as a hollow shape, 0.2-50 mm is preferable in this case, and 1-20 mm is more preferable. If the thickness in the case of a solid body or the thickness in the case of a hollow body is too thin, it may be difficult to obtain a reinforcing effect. If it is too thick, more materials are required, which is disadvantageous in terms of economy and weight reduction. Further, the thickness and thickness of the boss need not be uniform, and can be locally increased or decreased. In this case, the increase / decrease width is not particularly limited, but the difference between the thickest part and the thinnest part is preferably within 5 times, more preferably within 2 times. The thickness can be changed in stages, and can be continuously changed with a taper or curvature, but from the viewpoint of avoiding stress concentration when a load is applied. It is preferable to change. The boss may be insert-molded with a metal part such as a nutsert inside.

[Composite material constituting the compact]
The reinforcing fibers contained in the molded body are discontinuous. The average fiber length of the reinforcing fibers is 10 to 100 mm. By a preferable production method of the molded article of the present invention described later, a molded article made of a fiber-reinforced composite material containing reinforcing fibers having an appropriate fiber length can be provided. As a result, not only static strength and rigidity, but also high physical properties are expressed against shock loads and long-term fatigue loads, and even when molding molded bodies with complex shapes, The orientation is not easily broken, and the in-plane two-dimensional random orientation of the reinforcing fibers inside the molded body can be maintained.

  Usually, when the molding component is only a thermoplastic resin, if the molding conditions are strict, the melt viscosity of the resin decreases, so that the upright portions such as ribs and bosses are higher and can be made thinner. Moreover, it becomes possible to shape in a complicated shape, and a greater reinforcement effect can be imparted with less material. However, in the case of a composite material, the reinforcing material tends to hinder fluidity. In particular, in the fiber reinforced composite material, the fluidity of the material tends to be remarkably lowered because the aspect ratio of the reinforcing fiber is large. If the length of the reinforcing fiber is shortened and the aspect ratio is reduced, the fluidity of the material is increased, but the reinforcing effect is lowered. Further, in the case of a composite material having high fluidity in the past, the reinforcing material has a high tendency to be oriented in the flow direction, and even if the strength is high in the flow direction of the material, the strength does not increase in the direction orthogonal to the flow, and the physical properties of the molded body are low. It was anisotropic. For this reason, in order to make the physical properties of a molded body comprising a composite material isotropic, the thickness of the molded body needs to be increased. Not only was the height too high. On the other hand, since the molded body of the present invention uses a random mat that is isotropically highly fluidized as a constituent component, it is easier to form an upright part. In addition, since a more complicated shape can be formed thinner and higher, a reinforcing effect can be imparted with less material.

  The average fiber length of the reinforcing fibers is more preferably 15 to 100 mm, still more preferably 15 to 80 mm. The average fiber length of the reinforcing fibers is most preferably 20 to 60 mm.

The molded body in the present invention has a layer which is in-plane two-dimensional random orientation and is substantially isotropic. (Substantially isotropic here means that after forming a composite material, a tensile test based on an arbitrary direction of the molded plate and a direction orthogonal thereto is performed, the tensile modulus is measured, and the measured tensile force is measured. (The ratio (Eδ) obtained by dividing the larger elastic modulus value by the smaller elastic modulus value is 1.3 or less.)
The molded body of the present invention is composed of discontinuous reinforcing fibers having a fiber length of 10 to 100 mm and a thermoplastic resin, and the amount of the thermoplastic resin in the fiber-reinforced composite material is preferably 100 parts by weight of the reinforcing fibers, 50 to 1000 parts by weight, more preferably 50 to 500 parts by weight. More preferably, it is 60 to 300 parts by weight of the thermoplastic resin with respect to 100 parts by weight of the reinforcing fiber. If the ratio of the thermoplastic resin to 100 parts by weight of the reinforcing fiber is less than 50 parts by weight, voids are likely to be generated in the composite material, and the strength and rigidity may be lowered. On the other hand, if the ratio of the thermoplastic resin is more than 1000 parts by weight, the reinforcing effect of the reinforcing fiber may be difficult to express.

  In other words, in terms of fiber volume content (Vf), in the molded body and fiber reinforced composite material of the present invention, the fiber volume content is 5 to 80%, more preferably 20 to 60%. If the fiber volume content of the reinforcing fiber is lower than 5%, the reinforcing effect may not be sufficiently exhibited. If it exceeds 80%, voids are likely to occur in the composite material, and the physical properties of the molded article may be lowered.

  In the molded body of the present invention, it is possible to obtain a fiber volume content (Vf) that is substantially equal in each part having different thicknesses, and also to incline the carbon fiber content. It can be selected appropriately according to the application. In order to achieve a certain fiber reinforcing effect in each part having different thicknesses, it is preferable that Vf is substantially the same as other parts. The fact that Vf in each part is almost the same means that the ratio of the larger value divided by the smaller value is 1.0 to 1.2.

  It is one of the features of the present invention that the molded body of the present invention can maintain a constant fiber length and fiber content at each portion even in the upright portion extending in the vertical direction with respect to the horizontal portion. The present invention is a molded body composed of a fiber reinforced composite material in which discontinuous reinforcing fibers are present in a thermoplastic resin in a random orientation, and has an upright portion extending in a vertical direction with respect to a horizontal portion. A molded body having a fiber volume content (Vf) of 5 to 80% is included. The fiber volume content is more preferably 20 to 60%. It is preferable that the reinforcing fiber in the upright portion is continuously present from the horizontal portion to the upright portion. The average fiber length of the reinforcing fibers in the upright portion is 5 to 100 mm, preferably 5 to 80 mm, although it depends on the shape of the upright portion.

  The fiber volume content (Vf) in the upright portion extending in the vertical direction with respect to the horizontal portion and the other portions can be substantially the same, or can be appropriately changed depending on the portions. It is preferable that Vf is substantially the same as the other parts in the upright part for the purpose of fiber reinforcement. The fact that Vf in each part is almost the same means that the ratio of the larger value divided by the smaller value is 1.0 to 1.2.

The ratio of the reinforcing fiber and the thermoplastic resin in the composite material and the molded body can be evaluated using the difference in solubility. In this case, the weighed weight from 1 cm ² of 10 cm ² sample, may be extracted dissolved components either fibers or a resin dissolved or using decompose chemicals. Thereafter, the residue is weighed after washing and drying, and the volume fraction of the fiber and the resin is calculated from the weight of the residue and the dissolved component and the specific gravity of the fiber and the resin. For example, when the thermoplastic resin is polypropylene, only the polypropylene can be dissolved by using heated toluene or xylene. When the thermoplastic resin is polyamide, the polyamide can be decomposed by heated formic acid. When the resin is polycarbonate, the polycarbonate can be dissolved by using heated chlorinated hydrocarbon. When the reinforcing fiber is an inorganic fiber such as carbon fiber or glass fiber, the weight and volume fraction can be calculated by burning and removing the resin. In this case, after weighing the well-dried sample, the resin component is burned by treatment at 500 to 700 ° C. for 5 to 60 minutes using an electric furnace or the like. The weight of each component can be calculated by weighing the fibers remaining in a dry atmosphere after cooling.

  The reinforcing fiber constituting the fiber reinforced composite material is not particularly limited, and is an inorganic fiber such as carbon fiber, glass fiber, stainless steel fiber, alumina fiber, mineral fiber, polyether ether ketone fiber, polyphenylene sulfide fiber, polyether sulfone fiber, aramid. Examples thereof include organic fibers such as fibers, polybenzoxazole fibers, polyarylate fibers, polyketone fibers, polyester fibers, polyamide fibers, and polyvinyl alcohol fibers. Among these, in applications where the molded body is required to have strength and rigidity, it is preferably at least one selected from the group consisting of carbon fibers, aramid fibers, and glass fibers. For applications that require electrical conductivity, carbon fibers are preferred, and carbon fibers coated with a metal such as nickel are more preferred. In applications that require electromagnetic wave transparency, glass fibers and organic fibers are preferred, and aramid fibers and glass fibers are more preferred from the balance of electromagnetic wave permeability and strength. In applications where impact resistance is required, organic fibers are preferable, and polyamide fibers and polyester fibers are more preferable in consideration of cost. Among these, carbon fiber is preferable in that it can provide a composite material that is lightweight but has excellent strength.

The average fiber diameter of the reinforcing fibers is not particularly limited. For example, in the case of carbon fibers, the preferable average fiber diameter is 3 to 12 μm, and more preferably 5 to 7 μm. In the case of polyester fibers, the preferred average fiber diameter is 10 to 50 μm, more preferably 15 to 35 μm.
The average fiber diameter of the reinforcing fibers is not particularly limited. For example, in the case of carbon fibers, the preferable average fiber diameter is 3 to 12 μm, and more preferably 5 to 7 μm. In the case of polyester fibers, the preferred average fiber diameter is 10 to 50 μm, more preferably 15 to 35 μm.

  These can also be used in combination, and the type of reinforcing fiber can be properly used depending on the part of the molded body, and a molded body is produced in a state where composite materials using different reinforcing fibers are laminated in whole or in part. Is also possible.

  The molded body of the present invention can be obtained by molding a fiber-reinforced composite material composed of a random mat described later. In the composite material, it is preferable that the thermoplastic resin is impregnated in the fiber bundles of the reinforcing fibers and between the single yarns, and the impregnation degree is more preferably 90% or more. More preferably, the impregnation degree of the resin into the reinforcing fibers is 95% or more. If the degree of impregnation is low, there is a possibility that the physical properties of the composite material and the molded body may not reach the required level. Even in a molded body made of a fiber-reinforced composite material, the fiber length of the reinforcing fiber of the reinforcing fiber and the ratio of the bundle to the single yarn are maintained in the state in the random mat.

  Examples of the thermoplastic resin constituting the fiber reinforced composite material include vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol resin, polystyrene resin, acrylonitrile-styrene resin (AS resin), acrylonitrile-butadiene-styrene resin ( ABS resin), acrylic resin, methacrylic resin, polyethylene resin, polypropylene resin, polyamide 6 resin, polyamide 11 resin, polyamide 12 resin, polyamide 46 resin, polyamide 66 resin, polyamide 610 resin, polyacetal resin, polycarbonate resin, polyethylene terephthalate resin, Polyethylene naphthalate resin, Boribylene terephthalate resin, Polyarylate resin, Polyphenylene ether resin, Polyphenylene sulfide resin, Polysulfur Down resins, polyether sulfone resins, polyether ether ketone resins, such as polylactic acid resins.

  In addition, you may make a fiber reinforced composite material contain a functional filler and additive in the range which does not impair the objective of this invention. Examples include organic / inorganic fillers, flame retardants, UV-resistant agents, pigments, mold release agents, softeners, plasticizers, surfactants, and the like, but are not limited thereto. Particularly in electronic / electric equipment applications and automotive applications, high flame retardancy may be required, so it is preferable to include a flame retardant in the thermoplastic resin. As an example of a flame retardant, a well-known thing can be used, and if it can give a flame retardance to the thermoplastic composition of this invention, it will not specifically limit. Specific examples include phosphorus flame retardants, nitrogen flame retardants, silicone compounds, organic alkali metal salts, organic alkaline earth metal salts, bromine flame retardants, etc. These flame retardants can be used alone. Alternatively, a plurality of them may be used in combination. The content of the flame retardant is preferably 1 to 40 parts by mass and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the resin from the balance of physical properties, moldability, and flame retardancy.

[Random mat]
The random mat constituting the molded body of the present invention is composed of reinforcing fibers having a fiber length of 10 to 100 mm and a thermoplastic resin, and the reinforcing fibers are oriented substantially two-dimensionally at a basis weight of 25 to 3000 g / m ^2. In the reinforcing fiber bundle (A) constituted by the number of critical single yarns defined by the following formula (1), the ratio of the mat to the total amount of fibers is 30 Vol% or more and less than 90 Vol%, and the reinforcing fiber bundle ( The average number of fibers (N) in A) satisfies the following formula (2).
Critical number of single yarns = 600 / D (1)
0.7 × 10 ⁴ / D ² <N <6 × 10 ⁴ / D ² (2)
(Here, D is the average fiber diameter (μm) of the reinforcing fibers)
Here, “substantially two-dimensional random” means that the reinforcing fibers constituting the random mat and the composite material have the main orientation direction of the fiber axis in the contact surface of the composite material and are orthogonal to each other in the plane. It means that the ratio obtained by dividing the value of the tensile elastic modulus measured in the direction by the smaller one does not exceed 2.

  In the random mat constituting the molded body of the present invention, there is a fiber bundle composed of a single yarn state or less than the critical single yarn number as reinforcing fibers other than the reinforcing fiber bundle (A). That is, in the random mat used in the present invention, the opening of the reinforcing fibers is such that the abundance of reinforcing fiber bundles composed of the number of critical single yarns or more defined depending on the average fiber diameter is 30 Vol% or more and less than 90 Vol%. It is characterized by including a reinforcing fiber bundle composed of reinforcing fibers of a specific number or more whose degree is controlled and other opened reinforcing fibers in a specific ratio. When the ratio of the reinforcing fiber bundle (A) to the total amount of reinforcing fibers is less than 30 Vol%, there is an advantage that a molded article having excellent surface quality can be obtained, but it becomes difficult to obtain a molded article having excellent mechanical properties. When the ratio of the reinforcing fiber bundle (A) is 90 Vol% or more, the entangled portion of the fibers becomes locally thick, and it becomes difficult to obtain a thin-walled one.

  In addition, the random mat used in the present invention is characterized in that the average number of fibers (N) in the reinforcing fiber bundle (A) composed of the critical number of single yarns satisfies the above formula (2).

  Specifically, when the reinforcing fiber of the composite material is carbon fiber and the average fiber diameter of the carbon fiber is 5 to 7 μm, the critical single yarn number is 86 to 120, and the average fiber diameter of the carbon fiber is 5 μm. In this case, the average number of fibers in the fiber bundle is in the range of 280 to 2000, and 600 to 1600 is particularly preferable. When the average fiber diameter of the carbon fibers is 7 μm, the average number of fibers in the fiber bundle is in the range of 142 to 1020, preferably 300 to 800.

When the average number of fibers (N) in the reinforcing fiber bundle (A) is less than 0.7 × 10 ⁴ / D ² , it is difficult to obtain a high fiber volume content (Vf). In addition, when the average number of fibers (N) in the reinforcing fiber bundle (A) is 6 × 10 ⁴ / D ² or more, a locally thick portion is generated, which tends to cause voids. When trying to obtain a thin molded body having a thickness of 1 mm or less, the use of a fiber that has been simply split is large in density, and good physical properties cannot be obtained. Further, when all the fibers are opened, it becomes easy to obtain a thinner one, but the fiber entanglement increases, and a fiber having a high fiber volume content cannot be obtained. By making the reinforcing fiber bundle (A) equal to or higher than the critical single yarn defined by the formula (1) and the reinforcing fiber (B) having a single yarn state or less than the critical single yarn number simultaneously exist in the molded body, it is thin. It is possible to realize a molded body having a high physical property expression rate. The molded body of the present invention can have various thicknesses, but a thin product having a thickness of about 0.2 to 1 mm can also be suitably obtained.

There is no restriction | limiting in particular in the thickness of a random mat, The thing of 1-100 mm thickness can be obtained. The thickness is preferably 2 to 50 mm from the standpoint of exhibiting the effect of the present invention in that a molded article having a thinner thickness than that of the random mat of the present invention can be obtained.
The ratio of the reinforcing fiber and the thermoplastic resin in the random mat can be defined by the amount of each component charged during the production of the random mat. However, when it is desired to more accurately evaluate the ratio of fiber to resin, it can be confirmed by the following method. For example, as a method using the difference in solubility of constituent components, the weight of a sample of 1 cm ² to 10 cm ² is weighed. The dissolved component is extracted using a chemical that dissolves or decomposes either the fiber or the resin. The residue is then weighed after washing and drying. The volume fraction of the fiber and the resin is calculated from the weight of the residue and the dissolved component and the specific gravity of the fiber and the resin. For example, when the resin is polypropylene, only the polypropylene can be dissolved by using heated toluene or xylene. When the resin is polyamide, the polyamide can be decomposed by heated formic acid. When the resin is polycarbonate, the polycarbonate can be dissolved by using heated chlorinated hydrocarbon. When the reinforcing fiber is an inorganic fiber such as carbon fiber or glass fiber, the weight and volume fraction can be calculated by burning and removing the resin. In this case, after weighing the well-dried sample, the resin component is burned by treatment at 500 to 700 ° C. for 5 to 60 minutes using an electric furnace or the like. The weight of each component can be calculated by weighing the fibers remaining in a dry atmosphere after cooling.

The random mat used in the method for producing a molded article of the present invention contains reinforcing fibers and a thermoplastic resin. The types of reinforcing fiber and thermoplastic resin used are the same as those described in the section of the molded article.
The reinforcing fibers constituting the random mat are discontinuous and have an average fiber length of 10 to 100 mm. The random mat of the present invention is characterized in that it contains reinforcing fibers that are somewhat long and can exhibit a reinforcing function. The average fiber length of the reinforcing fibers is preferably 15 mm or more and 100 mm or less, more preferably 15 mm or more and 80 mm or less. Furthermore, 20 mm or more and 60 mm or less are preferable.

  The random mat used as the raw material of the molded article of the present invention contains a solid thermoplastic resin and becomes a preform for obtaining a fiber-reinforced composite material. In the random mat, the thermoplastic resin is preferably present in the form of fibers and / or particles. The presence of a mixture of reinforcing fibers and fibrous and / or particulate thermoplastic resins eliminates the need for large flow of fibers and resins in the mold of the impregnation step, and allows easy impregnation of thermoplastic resins. It is characterized by. Two or more types of thermoplastic resins can be used as long as they are compatible with each other, and fibrous and particulate materials may be used in combination.

  In the case of a fiber, a fineness of 100 to 5000 dtex, more preferably 1000 to 2000 dtex is more preferred, and an average fiber length of 0.5 to 50 mm is preferred, and an average fiber length of 1 to 10 mm is more preferred.

  In the case of particles, a spherical shape, a strip shape, or a columnar shape such as a pellet is preferable. In the case of a spherical shape, a perfect circular or elliptical rotating body or an egg-like shape is preferable. A preferable average particle diameter in the case of a sphere is 0.01 to 1000 μm. More preferably, the average particle size is 0.1 to 900 μm, and still more preferably the average particle size is 1 to 800 μm. The particle size distribution is not particularly limited, but a sharp distribution is more preferable for the purpose of obtaining a thinner molded product, but can be used as a desired particle size distribution by an operation such as classification.

  In the case of a strip shape, a columnar shape such as a pellet, a prismatic shape, or a flake shape is mentioned as a preferable shape. In this case, it may have a certain aspect ratio, but the preferred length is about the same as that of the above fibrous form.

[Layer structure of molded body]
The thin part which is the object of the present invention is that the horizontal part of the molded body and the upright part extending in the longitudinal direction with respect to the horizontal part have layers (X) in which the reinforcing fibers are substantially in-plane two-dimensional random orientation. It is preferable for obtaining a molded article that is lightweight, highly rigid and excellent in design. Here, “substantially in-plane two-dimensional random orientation” means that the reinforcing fiber constituting the fiber-reinforced composite material has the main orientation direction of the fiber axis in the contact surface of the fiber-reinforced composite material, and in that plane. It means that the ratio obtained by dividing the value of the tensile modulus measured in two directions perpendicular to each other by the smaller one does not exceed 1.3.

A layer (X) in which the reinforcing fibers are substantially two-dimensionally randomly oriented in the plane, and a layer (Y) in which the reinforcing fibers are continuously oriented in the horizontal part and the upright part at the joining part of the horizontal part and the upright part, and the reinforcement It is more preferable that the fibers have at least two kinds selected from the group consisting of layers (Z) that are not substantially two-dimensionally oriented in the plane and are not continuously oriented in the horizontal part and the upright part. The ratio of each layer is not particularly limited, but when the shape is thin and simple, the ratio of (X) and (Y) is high and the ratio of (Z) is low. When the shape is thick and complex, the ratio of (X) and (Y) is low, and the ratio of (Z) is high. In the former case, the ratio of (X) and (Y) to the plate thickness of the horizontal part is preferably 1 to 45%, and in the latter case, the ratio of (X) and (Y) to the plate thickness of the horizontal part is preferably used. A proportion of 1 to 30% is preferably used. As a result, not only can the strength of the confluence of the horizontal part and the upright part be ensured, but also light weight and high rigidity are realized in the thin part, and a layer (X) that is randomly oriented in two planes in the plane is secured at the thick part. However, it is possible to realize fiber flow that can cope with a three-dimensional complicated shape. In order to realize the ratio of the (X), (Y), (Z) layers in the molded body, the reinforcing fibers contained in the molded body have a critical single yarn number or more defined by the following formula (1). In the reinforcing fiber bundle (A) constituted by the following, the ratio to the total amount of reinforcing fibers in the molded body is 30 Vol% or more and less than 90 Vol%, and the average number of fibers (N) in the reinforcing fiber bundle (A) is represented by the following formula: It is important to satisfy (2). In addition, it is more preferable that the average fiber length is 10 to 100 mm in order to secure a layer that is substantially in-plane two-dimensional random orientation even in a molded body having a complicated shape.
Critical number of single yarns = 600 / D (1)
0.7 × 10 ⁴ / D ² <N <6 × 10 ⁴ / D ² (2)
(Here, D is the average fiber diameter (μm) of the reinforcing fibers)
When the usage of the molded body has a function of the outer plate of a product such as a housing or a panel-like member, it is preferable that a plurality of raised portions such as ribs and bosses are on the same surface side of the horizontal portion. In such a molded body, it is preferable that the layer (X) in which the reinforcing fibers are substantially two-dimensionally oriented in the plane is continuously present on the surface of the horizontal portion facing the upright portion. Thereby, not only a thin, lightweight, and highly rigid molded body can be obtained, but also the designability of the portion corresponding to the outer plate of the product can be enhanced. Such a layer structure can be preferably realized by controlling the molding conditions.

  In order to enhance the design of the molded body, it is possible to attach a decorative film to the outer surface side of the horizontal portion and / or the upright portion. The decorative film includes a transfer foil, a label with a picture, a film with a picture, etc. on which a desired decoration pattern such as letters, figures and patterns is formed on a base film. A method of transferring a decoration pattern of a decorative film or fusing or adhering the decorative film itself is generally known. In this case, a layer for filling surface irregularities of the molded body may be formed between the decorative film and the molded body. The decorative film may be affixed as a post-processing, and may be set in advance in a press mold and molded together with a fiber-reinforced composite material.

  When a large load acts on the molded body, it is possible to reinforce the horizontal portion and / or part of the upright portion with a unidirectional material. In this case, it is preferable to arrange a unidirectional material on the outer surface of the molded body, and it is more preferable to arrange it on both sides of the back and front to make a sandwich structure from the viewpoint of suppressing warpage during molding. Although there is no restriction | limiting in particular in the thickness of a unidirectional material, 5 to 100% of the thickness of the fiber reinforced composite material which shape | molded the random mat is preferable, and 10 to 50% is more preferable.

  The above-mentioned provisions such as the above-mentioned fiber bundle and average fiber length of the reinforcing fibers contained in the molded body are the provisions on the main part excluding the part such as the unidirectional material. The average fiber length is represented by an average value of the fiber lengths obtained by randomly taking out the reinforcing fibers contained in the molded body. A unidirectional material is a material in which continuous reinforcing fibers having a length of 100 mm or more are arranged in one direction in a thermoplastic resin (which may be the same as or different from the thermoplastic resin contained in the random layer). say. The unidirectional material used in the present invention may be a laminate of a plurality of continuous reinforcing fibers, or a laminate of continuous reinforcing fibers formed in a sheet shape and laminated at different angles (multiaxial fabric base material). Nylon yarn, polyester yarn, glass fiber yarn, and other stitch yarns that pass through the laminate in the thickness direction and are stitched by reciprocating between the front and back surfaces of the laminate along the surface direction. A shaft fabric may be used. In the unidirectional material, the abundance of the thermoplastic resin is preferably 50 to 1000 parts by weight with respect to 100 parts by weight of the reinforcing fibers. More preferably, it is 55 to 500 parts by weight of the thermoplastic resin with respect to 100 parts by weight of the reinforcing fiber, and more preferably 60 to 300 parts by weight of the thermoplastic resin with respect to 100 parts by weight of the reinforcing fiber.

[Method for producing molded article]
The molded body of the present invention includes the following steps A-1) to A-3) to perform impregnation to molding, or includes steps B-1) to B-4) to perform impregnation to molding. A method for producing a molded body having an upright portion extending in a longitudinal direction with respect to a horizontal portion made of a composite material,
A-1) When the thermoplastic resin is crystalline, the random mat is heated above the melting point and below the decomposition temperature, and when amorphous, it is heated above the glass transition temperature and below the decomposition temperature, and pressurized to reinforce the thermoplastic resin. Step A-2) Obtaining Prepreg by Impregnation into Bundle The temperature of the prepreg obtained in A-1) is adjusted to below the melting point when the thermoplastic resin is crystalline, and below the glass transition temperature when amorphous. Step A-3) in which the charging rate is 5 to 100% or less represented by the following formula (3) and pressurization is performed on the mold, and when the thermoplastic resin is crystalline, the melting point or less is amorphous. In the case of step B-1, the molding is completed by adjusting the mold temperature to be equal to or lower than the glass transition temperature. B-1) The mold is such that the random mat has a charge rate of 5 to 100% or less represented by the following formula (3). Step B-2) Place the mold on the thermoplastic resin In the case of the property of the thermoplastic resin up to a temperature not lower than the thermal decomposition temperature, and in the case of an amorphous material, the pressure is increased while raising the temperature to a temperature higher than the glass transition temperature of the thermoplastic resin and lower than the thermal decomposition temperature (first Pressing process)
B-3) A step of pressurizing so that the pressure in the final step is 1.2 to 100 times the pressure in the first press step (second press step).
B-4) When the thermoplastic resin is crystalline, it can be preferably produced by a step of completing molding by adjusting the mold temperature to below the melting point, and when it is amorphous, below the glass transition temperature.

  The method of impregnating to forming including steps A-1) to A-3) is a so-called cold press method. The method of impregnation to molding including the steps B-1) to B-4) is a so-called hot press method. Although both press moldings can be applied to the molded body of the present invention, the cold press method is more preferably used from the viewpoint of further shortening the molding time.

  The above process can be performed continuously following the manufacturing process of the random mat, or may be performed individually after obtaining the random mat.

  Moreover, in this invention, it arrange | positions with a low charge with respect to a metal mold | die shape, and makes a base material flow by pressurizing. By doing so, the base material is easily filled into a complicated shape. Usually, when a fiber reinforced composite material is flowed, the reinforcing fibers tend to be oriented in the flow direction, and anisotropy may occur in the physical properties. A complicated shape can be obtained while maintaining the isotropy of the fiber. The charge rate of the base material is preferably 5 to 100%, more preferably 20 to 95% in the following formula (3). A more preferable base material charge rate is 50 to 90%.

Charge rate = 100 × base material area (mm ² ) / mold cavity projected area (mm ² ) (3)
(Here, the base material area is the projected area of all the arranged random mats or prepregs in the removal direction, and the mold cavity projected area is the projected area in the removal direction.)
If the charge rate of the base material is lower than 5%, the base material may be cooled in the process of flowing during molding, and a molded product having a desired thickness may not be obtained. On the contrary, when the charge rate of the base material exceeds 100%, the feature of the present invention that the material is made to flow to some extent is not realized. Further, if the charge rate of the base material exceeds 100%, not only the loss of the base material is increased, but also post-processing such as trimming is required, which is disadvantageous in terms of productivity and cost.

[Prepreg]
In the present invention, when impregnation to molding is performed including the steps A-1) to A-3), the random mat is amorphous up to a temperature not lower than the melting point and lower than the thermal decomposition temperature when the thermoplastic resin is crystalline. In this case, by heating to a temperature not lower than the glass transition temperature and lower than the thermal decomposition temperature, a thermoplastic resin is impregnated to obtain a prepreg and used for molding. The form of the reinforcing fiber in the prepreg is kept in the random mat. That is, the reinforcing fibers in the prepreg maintain the fiber length, isotropy, and degree of opening in the random mat, and are the same as those described in the random mat.

  In the prepreg, the step A-2) may be performed as it is without cooling, or the step of A-2) may be performed after the step of once impregnating and solidifying the thermoplastic resin. In the prepreg, the thermoplastic resin may be partially melted and welded, but is preferably present in the form of fibers and / or particles. The reinforcing fiber and the fibrous and / or particulate thermoplastic resin are mixed and exist in the vicinity of the reinforcing fiber, so that the thermoplastic resin can be easily impregnated at the time of molding. As described above, the random mat is characterized in that it can be easily impregnated with the thermoplastic resin because the reinforcing fiber and the fibrous or particulate thermoplastic resin are mixed. The prepreg is preferably 1 to 10 times, preferably 1 to 5 times the thickness of the molded product to be obtained. Although there is no limitation on the thickness, it is preferably 0.1 mm or more, and the upper limit may be about 30 mm as long as it can be placed in a mold and molded.

  The prepreg preferably has a void ratio of 0 to 30% in order to suppress the impregnation failure of the resin during molding as much as possible. The void ratio of the prepreg is calculated by observing the cross section of the prepreg with an optical microscope and dividing the existing area of the void by the cross sectional area of the observation substrate. In the observation, n = 5 per prepreg, and the average value is defined as the void ratio.

[Cold press method]
The case where impregnation and molding are performed including the steps A-1) to A-3) (in the case of the cold press method) will be specifically described. As described above, in step A-1), A-1) the random mat is heated to a melting point or higher and lower than the decomposition temperature when the thermoplastic resin is crystalline, and when amorphous, it is heated to a glass transition temperature or higher and lower than the decomposition temperature. A prepreg is obtained by applying pressure and impregnating the thermoplastic resin into the reinforcing fiber bundle. The obtained prepreg is maintained at a temperature not lower than the melting point and lower than the thermal decomposition temperature when the thermoplastic resin is crystalline, or maintained at a temperature not lower than the glass transition temperature and lower than the thermal decomposition temperature in the case of amorphous, or is reheated. Used in step A-2). The temperature of the prepreg can be measured by, for example, a measuring instrument in which a K-type thermocouple is attached to the prepreg surface and installed outside the heating furnace.

In step A-2), the prepreg is placed in a mold whose temperature is adjusted below the melting point when the thermoplastic resin is crystalline, and below the glass transition temperature when amorphous, and is molded by press molding. The temperature of the mold may be a melting point of −200 ° C. or higher and a melting point of −10 ° C. or lower when the thermoplastic resin is crystalline, and a glass transition temperature of −200 ° C. or higher and a glass transition temperature of −10 ° C. or lower when amorphous. preferable. After the prepreg is cooled in the mold to obtain a molded body, the molded body can be taken out from the mold. There is no particular limitation on the mold cooling method, and the mold may be appropriately cooled by a method of flowing a cooling medium through the mold temperature control circuit.
The prepreg is arranged in the mold so that the charge rate represented by the following formula (3) is 5% or more and 100% or less.

Charge rate (%) = 100 × base material area (mm ² ) / mold cavity projection area (mm ² ) (3) (Here, the base material area is the projected area in the drawing direction of all the prepregs arranged. The mold cavity projected area is the projected area in the punching direction)
For example, one or 2 to 10 superposed prepregs can be placed in the mold cavity. In the case of superposing, a part or the whole is superposed and used according to the molded product to be obtained. Here, it is desirable that a part or all of the prepreg end portion does not contact the mold cavity edge portion. In the case of overlapping, the prepregs need not all have the same shape, but may be partially or entirely overlapped.

  In step A-3), the mold is clamped and the heated prepreg is pressurized to the target pressure to complete the shaping. The time to reach the target pressure is preferably 1 to 10 seconds. The target pressure is 0.3 MPa to 100 MPa, preferably 5 MPa to 40 MPa. After reaching the target pressure, the mold is opened after cooling to the melting point or lower in the case of crystallinity of the thermoplastic resin and below the glass transition temperature in the case of amorphousness by heat exchange with the mold to obtain a molded body.

  When the charge rate is less than 5%, it is possible to obtain a molded body in which the molded body is filled with fibers up to the end of the mold without generation of cracks, wrinkles, and warpage. Since a region where a randomly oriented layer cannot be secured increases, the physical property expression rate and the design property tend to be lowered.

  When the charge rate exceeds 100% and the mold has an open cavity structure, it is possible to obtain a molded body filled with fibers up to the end of the mold, but when molding a product having a complicated shape, Thickness changes with respect to the product design thickness due to drawing or tension, making control difficult and particularly the end face tend to be thin. Control is more difficult with a product having an uneven shape. In addition, burrs are generated at the end of the molded body, and trimming by machining or the like in post-processing is necessary, which not only complicates the process but also causes material loss.

When the charge rate exceeds 100% and the mold has a closed cavity structure, there is no material cracking or wrinkling, the surface appearance is good, the product is not warped, and the mold is maintained substantially isotropic, A molded product filled with fibers up to the end can be obtained, but since the end face of the product is trimmed at the shear edge of the mold, damage is caused to the shear edge, so long-term continuous Not suitable for use. In addition, when the product shape is complicated, the shear edge portion first contacts the prepreg at the time of shaping, and the follow-up to the mold is hindered, making it difficult to control the product thickness.
By setting the charge rate to 5% or more and less than 100%, a lightweight molded body can be produced at a high level without generating material loss and trimming while ensuring a layer in which reinforcing fibers are substantially two-dimensionally aligned in the plane. It becomes possible to manufacture with the property.

  The thickness of the prepreg in the mold can be appropriately selected according to the thickness of the shape to be obtained. However, when the charging rate of the base material to the mold is 5% or more and 80% or less, the total thickness of the prepreg or the laminated thickness of the prepreg may be 1.0 mm or more in order to appropriately flow. preferable.

[Hot press molding]
The case where impregnation-molding including the steps B-1) to B-4) is specifically described.
In B-1), the random mat is placed in the mold so that the charge rate represented by the following formula (3) is 5% or more and less than 100%.
Charge rate (%) = 100 × base material area (mm ² ) / mold cavity projected area (mm ² ) (3) (Here, the base material area is the projected area in the removal direction of all the arranged random mats. Yes, the mold cavity projected area is the projected area in the punching direction)
For example, as shown in FIG. 1, one or two to ten random mats are arranged in the mold cavity. When superposing, a part or the whole is superposed and used depending on the molded product to be obtained. Here, it is desirable that part or all of the surface of the end portion of the random mat is not in contact with the mold cavity edge portion. In the case of overlapping, the random mats need not all have the same shape, and may be partially or entirely overlapped.

  Next, in step B-2), when the thermoplastic resin is crystalline, the mold is thermally decomposed to a temperature not lower than the melting point of the thermoplastic resin and lower than the thermal decomposition temperature, and in the case of amorphous, not lower than the glass transition temperature of the thermoplastic resin. Pressurization is performed while raising the temperature to below the temperature (first pressing step).

  Next, in step B-3), a second pressing step is performed in which the number of steps is one or more and the pressure in the final step is 1.2 to 100 times the pressure in the first pressing step.

  In the first pressing step, the random mat is pressurized to the first target pressure, and is preferably held for 0.5 to 20 minutes. If the thermoplastic resin is crystalline, the thermoplastic resin is thermally decomposed to a temperature equal to or higher than the melting point of the thermoplastic resin. When it is amorphous, it is warmed to a temperature that is not lower than the glass transition temperature of the thermoplastic resin and lower than the thermal decomposition temperature. Next, the time during which the process proceeds to the second pressing step can be appropriately selected depending on the performance of the molding machine, but is preferably 1 to 10 seconds in order to reduce the molding time.

  The second pressing step is a step of performing one-stage or multi-stage pressurization, but it is preferably one stage for the purpose of simplifying the molding. The mold temperature in the second pressing step may be the same as the mold temperature in the first pressing step or may be raised to 1 ° C. or higher and lower than the thermal decomposition temperature. When the second pressing step is multistage, the temperature may be raised or cooled as the latter stage, and the temperature raising and cooling may be performed alternately.

  The total pressing time in the second pressing step is not particularly limited, but is preferably 0.5 to 10 minutes from the viewpoint of shortening the molding time.

  The target pressure in the first pressing step is 0.3 MPa to 1.0 MPa, preferably 0.5 MPa to 0.7 MPa. Although the final target pressure in the second pressing step can be appropriately selected depending on the performance of the molding machine, it is preferably 1 to 100 MPa, more preferably 2 to 10 MPa, and more preferably 2 to 5 MPa. The final target pressure in the second pressing step is 1.2 to 100 times that in the first pressing step. That is, it is preferable that the molding pressure in B-2 to B-3 is 0.3 MPa to 100 MPa.

  After the second pressing step, in step B-4), using a cooling medium, the mold is cooled to the melting point or lower when the thermoplastic resin is crystalline, and to the glass transition temperature or lower when the thermoplastic resin is amorphous. obtain. The temperature after cooling should be a melting point of −200 ° C. or higher and a melting point of −10 ° C. or lower when the thermoplastic resin is crystalline, and a glass transition temperature of −200 ° C. or higher and a glass transition temperature of −10 ° C. or lower when amorphous. Is preferred. The time required for the cooling step can be appropriately controlled depending on the cooling conditions and the like, but is preferably 0.5 to 5 minutes from the viewpoint of shortening the molding time.

  There is no particular limitation on the mold cooling method, and the mold may be appropriately cooled by a method of flowing a cooling medium through the mold temperature control circuit.

  When the charge rate is less than 5%, it is possible to obtain a molded body in which the molded body is filled with fibers up to the end of the mold without generation of cracks, wrinkles, and warpage. Since a region where a randomly oriented layer cannot be secured increases, the physical property expression rate and the design property tend to be lowered.

  The thickness of the random mat in the mold can be appropriately selected according to the thickness of the shape to be obtained. However, in order to appropriately flow, it is preferable that the thickness of the random mat or the total thickness of the stacked random mats is 0.5 mm or more.

EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these.
1) Analysis of reinforcing fiber bundle in random mat The method for obtaining the ratio of reinforcing fiber bundle (A) to the total amount of fibers in the mat is as follows.
A random mat is cut into 100 mm × 100 mm, and the thickness (Ta) and weight are measured (Wa).
From the cut out mat, all the fiber bundles are taken out with tweezers, and the fiber bundles are classified by thickness. In this embodiment, the classification is performed in units of about 0.2 mm in thickness.
For each classification, the length (Li) and weight (Wi) of all fiber bundles and the number of fiber bundles (I) are measured and recorded. When the fiber bundle is so small that it cannot be taken out by tweezers, the weight is finally measured together (Wk). At this time, a balance capable of measuring up to 1/1000 g is used. In particular, when the reinforcing fiber is a carbon fiber, or when the fiber length is short, the weight of the fiber bundle is small and measurement is difficult. In such a case, a plurality of classified fiber bundles are collected and the weight is measured.
After the measurement, the following calculation is performed. From the fineness (F) of the reinforcing fiber used, the number of fibers (Ni) of each fiber bundle was obtained by the following equation.
Ni = Wi / (Li × F).
The average number of fibers (N) in the reinforcing fiber bundle (A) is determined by the following formula.
N = ΣNi / I
Moreover, the volume (Vi) of each fiber bundle and the ratio (VR) of the reinforcing fiber bundle (A) to the whole fiber were obtained by the following formula using the fiber specific gravity (ρ) of the used reinforcing fiber.
Vi = Wi / ρ
VR = ΣVi / Va × 100
Here, Va is the volume of the cut out mat, Va = 100 × 100 × Ta

2) Reinforcing fiber bundle analysis in molded body The molded body was measured in the same manner as in the above random mat after the resin was burned and removed in a furnace at 500 ° C for 1 hour.

3) Analysis of fiber orientation in the molded body After molding the composite material, the fiber isotropy is measured by conducting a tensile test based on any direction of the molded plate and the direction orthogonal thereto, and measuring the tensile modulus. It was confirmed by measuring a ratio (Eδ) obtained by dividing a larger value of the measured tensile modulus by a smaller value. The closer the modulus ratio is to 1, the better the material is.

4) Analysis of the average fiber length of the reinforcing fibers contained in the molded body The average fiber length of the reinforcing fibers contained in the obtained molded body was randomly determined after removing the resin in the furnace for about 500 ° C x 1 hour. The length of 100 extracted reinforcing fibers was measured and recorded to the 1 mm unit with a magnifying glass, and the average fiber length (La) was determined from the measured lengths (Li) of all the reinforcing fibers by the following formula.
La = ΣLi / 100

5) Analysis of fiber volume content in the molded body The molded body was subjected to combustion removal in the furnace at 500 ° C. for 1 hour, and the weight of the fiber and the resin was calculated by weighing the sample before and after the treatment. did. Next, the fiber volume content was calculated using the specific gravity of each component.

6) Fillability evaluation For the purpose of evaluating the fluidity and moldability of the random mat and the composite material, the appearance of the molded body, particularly the ends of ribs and bosses, was visually evaluated. ○ When the material is filled up to the end of the rib or boss and there are no defects in the molded body, △ when there is a slight defect △, when the filling is insufficient and there are obvious defects in the molded body × It was.

7) Evaluation of dimensional stability As a measure of dimensional stability, the presence or absence of warpage was evaluated. After molding, the molded body, which was sufficiently left to cool to room temperature, was checked for warpage on a flat surface. A warp of less than 1 mm was indicated by ◯, 1-5 mm by Δ, and 5 mm or more by x.

[Reference Example 1]
While opening carbon fiber (manufactured by Toho Tenax Co., Ltd .: Tenax STS40-24KS (fiber diameter 7 μm, fiber width 10 mm)) to a width of 20 mm, the fiber length is cut to 10 mm, and the supply amount of carbon fiber is 301 g / min in a tapered tube The air was blown onto the carbon fiber in the taper tube, and the fiber bundle was partially opened to spread on the table installed at the lower part of the taper tube outlet. Further, as a matrix resin, a polycarbonate resin (polycarbonate manufactured by Teijin Kasei Co., Ltd .: Panlite L-1225L, glass transition temperature 145 to 150 ° C., thermal decomposition temperature 350 ° C.) tapered to an average particle size of about 710 μm is tapered at 480 g / min. A random mat having a thickness of about 1 mm, in which carbon fibers having an average fiber length of 10 mm and polycarbonate were mixed, was obtained by being supplied into the tube and sprayed simultaneously with the carbon fibers. When the average fiber length (La) and the ratio of the reinforcing fiber bundle (A) and the average number of fibers (N) of the obtained random mat were examined, the average fiber length (La) was defined as 10 mm and the formula (3). The number of critical single yarns was 86, and with respect to the reinforcing fiber bundle (A), the ratio of the mat to the total amount of fibers was 35%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 240.

[Reference Example 2]
Carbon fiber (manufactured by Toho Tenax Co., Ltd .: Tenax IMS60-12K (average fiber diameter 5 μm, fiber width 6 mm)) is cut to a length of 20 mm, and the carbon fiber supply rate is introduced into the tapered tube at 1222 g / min. The air was blown onto the carbon fiber, and the fiber bundle was partially opened while being spread on a table installed at the lower part of the tapered tube outlet. Further, as a matrix resin, PA66 fiber (polyamide 66 fiber manufactured by Asahi Kasei Fiber: T5 nylon (fineness: 1400 dtex) melting point: 260 ° C., thermal decomposition temperature: about 310 ° C.) supplied to the taper tube at 3000 g / min is supplied into the tapered tube as carbon resin. By dispersing simultaneously with the fibers, a random mat having a thickness of about 10 mm in which carbon fibers having an average fiber length of 20 mm and polyamide 66 were mixed was obtained. When the average fiber length (La) and the ratio of the reinforcing fiber bundle (A) and the average number of fibers (N) of the obtained random mat were examined, the average fiber length was 20 mm and the critical unit defined by the formula (3) was used. The number of yarns was 120. Regarding the reinforcing fiber bundle (A), the ratio of the mat to the total amount of fibers was 86%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 900.

[Reference Example 3]
Glass fiber (manufactured by Nippon Electric Glass Co., Ltd .: EX-2500 (average fiber diameter 15 μm, fiber width 9 mm) is cut into a length of 50 mm, the glass fiber supply rate is 412 g / min, introduced into the taper tube, and the air in the taper tube The fiber bundle was sprayed onto a carbon fiber and partially spread to spread it on a table installed at the bottom of the taper tube outlet, and as a matrix resin, a polypropylene resin (prime) freeze-ground to an average particle size of about 1 mm was used. Polymer polypropylene: Prime Polypro J108M Melting point 170 ° C., thermal decomposition temperature 280 ° C.) is fed into the tapered tube at 600 g / min and sprayed simultaneously with the glass fibers to mix glass fibers with an average fiber length of 50 mm and PP. A random mat having a thickness of about 1 mm was obtained, and the average fiber length (L ) And the ratio of the reinforcing fiber bundle (A) and the average number of fibers (N), the average fiber length (La) is 50 mm, the critical single yarn number defined by the formula (3) is 40, and the reinforcing fibers Regarding the bundle (A), the ratio of the mat to the total amount of fibers was 68%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 60.

[Reference Example 4]
While opening carbon fiber (manufactured by Toho Tenax Co., Ltd .: Tenax STS40-24KS (fiber diameter 7 μm, fiber width 10 mm)) to a width of 20 mm, the fiber length is cut to 10 mm, and the supply amount of carbon fiber is 301 g / min in a tapered tube In the taper tube, air was not sprayed on the carbon fiber, but was sprayed on a table installed at the lower part of the taper tube outlet. Further, as a matrix resin, a polycarbonate resin (polycarbonate manufactured by Teijin Chemicals: Panlite L-1225L, glass transition temperature 145 to 150 ° C., thermal decomposition temperature 350 ° C.) frozen and pulverized to an average particle size of about 710 μm in a tapered tube at 480 g / min. And a random mat having a thickness of about 1 mm, in which carbon fibers having an average fiber length of 10 mm and polycarbonate were mixed, was obtained. When the average fiber length (La) and the ratio of the reinforcing fiber bundle (A) and the average number of fibers (N) of the obtained random mat were examined, the average fiber length (La) was defined as 10 mm and the formula (3). The number of critical single yarns was 86, and with respect to the reinforcing fiber bundle (A), the ratio of the mat to the total amount of fibers was 100%, and the average number of fibers (N) in the reinforcing fiber bundle (A) was 24000.

  The random mats produced in Reference Examples 1 to 4 were impregnated and molded using a 500-ton hydraulic press manufactured by Kawasaki Oil Works. The mold shown in FIGS. 1 and 2 was used as the mold for molding.

[Example 1]
The random mat produced in Reference Example 1 was hot-pressed at 300 ° C. and 4 MPa for 5 minutes using a press machine manufactured by Kawasaki Yoko Co., Ltd. in which a flat plate mold for impregnation was set, and then cooled to 50 ° C. A composite material base material of 99%, a thickness of 0.6 mm, and a fiber volume content of 30% was obtained.
Next, the obtained composite material base material was heated to 300 ° C. using an IR oven made by NGK Kilntech, and four layers were stacked. On the horizontal part of the mold shown in FIG. The battery was placed at a charge rate of 80% and cold pressed at a pressure of 10 MPa for 60 seconds.
The obtained molded body was filled with the composite material up to the side walls and the ends of the respective ribs and bosses (◯). When the tensile elastic modulus of the horizontal part, the side wall, and the rib part of the molded body was measured, the ratio of the tensile elastic modulus in two directions perpendicular to each other was 1.04 to 1.05, and the isotropic property was maintained. It was confirmed. As a result of measuring the fiber volume content of the horizontal part of the molded body and the boss part, both were 30% and there was no difference. Further, the warpage of the molded body was 1 mm or less, and good dimensional stability was shown (◯).

[Example 2]
The random mat produced in Reference Example 2 was hot-pressed at 280 ° C. and 3 MPa for 5 minutes using a press machine manufactured by Kawasaki Yoko Co., Ltd. in which a flat plate mold for impregnation was set, and then cooled to 50 ° C. A composite material base material of 99%, a thickness of 3.2 mm, and a fiber volume content of 20% was obtained.
Next, the obtained composite material base material was heated to 280 ° C. using an IR oven made by NGK Kiln Tech, and the charge rate of 60 was applied to the horizontal part of the mold shown in FIG. % Was cold pressed for 60 seconds at a pressure of 10 MPa.
The obtained molded body was filled with the composite material up to the side walls and the ends of the respective ribs and bosses (◯). When the tensile elastic modulus of the horizontal part, the side wall, and the rib part of the molded body was measured, the ratio of the tensile elastic modulus in two directions perpendicular to each other was 1.09 to 1.10. It was confirmed. As a result of measuring the fiber volume content of the horizontal part of the molded body and the boss part, both were 20% and there was no difference. Further, the warpage of the molded body was 1 mm or less, and good dimensional stability was shown (◯).

[Example 3]
The random mat produced in Reference Example 3 was hot-pressed at 220 ° C. and 3 MPa for 5 minutes using a press machine manufactured by Kawasaki Yoko Co., Ltd. in which a flat plate mold for impregnation was set, then cooled to 50 ° C., and the degree of resin impregnation A composite material base material of 99%, a thickness of 0.6 mm, and a fiber volume content of 20% was obtained.
Next, the obtained composite material base material was heated up to 220 ° C. using an IR oven made by NGK Kiln Tech, 4 sheets were stacked, and the mold temperature was set to 100 ° C. on the horizontal part of the mold in FIG. The battery was placed at a charge rate of 80% and cold pressed at a pressure of 10 MPa for 60 seconds.
The obtained molded body was filled with the composite material up to the side walls and the ends of the respective ribs and bosses (◯). When the tensile elastic modulus of the horizontal part, the side wall, and the rib part of the molded body was measured, the ratio of the tensile elastic modulus in two directions perpendicular to each other was 1.07 to 1.08, and the isotropic property was maintained. It was confirmed. As a result of measuring the fiber volume content of the horizontal part of the molded body and the boss part, both were 20% and there was no difference. Further, the warpage of the molded body was 1 mm or less, and good dimensional stability was shown (◯).

[Example 4]
Four random mats produced in Reference Example 1 were stacked and placed at a mold horizontal part of a Kawasaki Yoko press machine set with the mold of FIG. 1 at a charge rate of 80% at 300 ° C. and 10 MPa. After hot pressing for 7 minutes, the product was cooled to 50 ° C. to obtain a molded article having a resin impregnation degree of 99%, a thickness of 2.0 mm, and a fiber volume content of 30%.
The obtained molded body was filled with the composite material up to the side walls and the ends of the respective ribs and bosses (◯). When the tensile elastic modulus of the horizontal part, the side wall, and the rib part of the molded body was measured, the ratio of the tensile elastic modulus in two directions perpendicular to each other was 1.12 to 1.13, and the isotropic property was maintained. It was confirmed. As a result of measuring the fiber volume content of the horizontal part of the molded body and the boss part, both were 30% and there was no difference. Further, the warpage of the molded body was about 3 mm, and relatively good dimensional stability was shown (Δ).

[Comparative Example 1]
The random mat produced in Reference Example 4 was hot-pressed at 300 ° C. and 4 MPa for 5 minutes using a press machine manufactured by Kawasaki Yoko Co., Ltd. in which a flat plate mold for impregnation was set, then cooled to 50 ° C., and the degree of resin impregnation A composite material base material of 99%, a thickness of 0.6 mm, and a fiber volume content of 30% was obtained.
Next, the obtained composite material base material was heated to 300 ° C. using an IR oven made by NGK Kilntech, and four layers were stacked. On the horizontal part of the mold shown in FIG. The battery was placed at a charge rate of 80% and cold pressed at a pressure of 10 MPa for 60 seconds.
As for the obtained molded object, the unfilling place was confirmed in the edge part of a side wall, a rib, and a boss | hub (x). When the tensile elastic modulus of the horizontal part, the side wall, and the rib part of the molded body was measured, the ratio of the tensile elastic modulus in two directions perpendicular to each other was 2.05 to 2.35, which was anisotropic. As a result of measuring the fiber volume content of the horizontal part of the molded body and the boss part, a difference was seen at 24% for the boss with respect to 30% for the horizontal part. Further, the warpage of the molded body was about 10 mm, and there was a problem in dimensional stability. (X).

1 Horizontal part Length 400mm, width 200mm, thickness 2mm
2 Side wall height 30mm, thickness 2mm
3A Rib 1 Height 30mm, thickness 2mm
3B Rib 2 Height 10-30mm, thickness 2mm
3C Rib 3 Height 10-30mm, thickness 1mm
4A Boss 1 Height 30mm, Hollow part diameter 5mm, Wall thickness 2mm
4B Boss 2 Height 15mm, Hollow part diameter 5mm, Wall thickness 2mm
4C boss 3 height 30mm, hollow part diameter 5mm, wall thickness 1mm
4D boss 4 height 15mm, hollow part diameter 5mm, wall thickness 1mm

Claims (5)

For a random mat composed of a reinforcing fiber and a thermoplastic resin having an average fiber length of 10 to 100 mm, cormorants row impregnation-molding comprises the following steps A-1) ~A-3) , made of fiber-reinforced composite material A method for producing a molded body having an upright portion extending in a vertical direction with respect to a horizontal portion,
A-1) When the thermoplastic resin is crystalline, the random mat is heated above the melting point and below the decomposition temperature, and when amorphous, it is heated above the glass transition temperature and below the decomposition temperature, and pressurized to reinforce the thermoplastic resin. Step A-2) Obtaining a prepreg by impregnating the bundle The temperature of the prepreg obtained in A-1) is adjusted below the melting point when the thermoplastic resin is crystalline, and below the glass transition temperature when the thermoplastic resin is amorphous. Step A-3) in which the charging rate is 5 to 100% or less represented by the following formula (3) and pressurization is performed on the mold, and when the thermoplastic resin is crystalline, the melting point or less is amorphous. as engineering to complete the molding by adjusting the mold temperature to below the glass transition temperature in the case of
La Ndamumatto are oriented substantially two dimensional random in reinforced fiber is 25~3000g / m ² basis weight, the reinforcing fiber bundle composed of a critical single yarn number or more as defined in the formula (1) (A ), The ratio of the mat to the total amount of fibers is 30 vol% or more and less than 90 vol%, and the average number of fibers (N) in the reinforcing fiber bundle (A) satisfies the following formula (2): The manufacturing method of the molded object which has an upright part extended to the vertical direction with respect to the horizontal part which consists of material.
Critical number of single yarns = 600 / D (1)
0.7 × 10 ⁴ / D ² <N <6 × 10 ⁴ / D ² (2)
(Here, D is the average fiber diameter (μm) of the reinforcing fibers)
Charge rate (%) = 100 × base material area (mm ² ) / mold cavity projected area (mm ² ) (3)
(Here, the substrate area is the projected area in the extraction direction of all the arranged random mats or prepregs, and the mold cavity projected area is the projected area in the extraction direction.)   The manufacturing method of the molded object of Claim 1 whose charge rate in Formula (3) is 50% or more and 90% or less.   The method for producing a molded body according to claim 1 or 2, wherein the upright portions extending in the vertical direction with respect to the horizontal portion are ribs and / or boss portions.   A fiber reinforced composite material of 50 to 1000 parts by weight of a thermoplastic resin with respect to 100 parts by weight of the reinforced fiber, and the smaller value of the fiber volume content (Vf) in the upright part and other parts. The molded object obtained by the manufacturing method in any one of Claims 1-3 used as the divided ratio 1.0-1.2. A molded article having a raised portion extending longitudinally with respect to the horizontal portion, the raised portion of their respective arbitrary direction, and the smaller the larger of the tensile modulus in the direction perpendicular thereto The molded product according to claim 4, wherein the ratio (Eδ) divided by the value of 1.0 is from 1.3 to 1.3.

Images