Method for producing composite material and method for producing molded body

Abstract

Provided is a composite material that enables warping and twisting to be suppressed and enables tact time to be reduced when forming a plate-shaped composite material. Also provided is a method for producing a plate-shaped composite material by heating, melting and causing to flow a plurality of small pieces Xi containing discontinuous reinforcing fibers and a thermoplastic resin, wherein: an arrangement region of the small pieces Xi forms a non-fluid region A in the produced composite material; a fluid region of the small pieces Xi forms a fluid region B in the produced composite material; the non-fluid region A and the fluid region B each contain the reinforcing fibers and the thermoplastic resin; and a relationship between a total area Sa of the non-fluid region A and an area Stotal of the entire plate-shaped composite material satisfies 0.4 × Stotal < Sa < 0.8 × Stotal.

Description

Method for manufacturing composite material and method for manufacturing molded body

[0001] The present disclosure relates to a method for manufacturing a composite material and a method for manufacturing a molded body.

[0002] Fiber reinforced plastics have light weight and high mechanical properties, and for molding, sheet-like fiber reinforced composite materials such as stamping sheets are used.

[0003] The invention described in Patent Document 1 is a press molding material in which a fiber reinforced resin sheet made of a reinforcing fiber base material and a thermoplastic resin is arranged on the surface of a prepreg made of a reinforcing fiber and a thermoplastic resin. The springback rate of the fiber reinforced resin sheet is 200% or more and less than 1000%, and the prepreg is 90% or more and less than 200%, improving the strength and formability of the molding material. The invention described in Patent Document 2 relates to a method for manufacturing a carbon fiber reinforced plastic using small pieces obtained by cutting a paper sheet or non-woven fabric containing carbon fibers and a matrix resin. The manufacturing process also includes making a paper sheet or non-woven fabric with carbon fibers, cutting it into small pieces, impregnating it with a matrix resin, and press molding. The small pieces have an area of 1 to 50 cm 2 and a thickness in the range of 0.1 to 2 mm, and these small pieces are assembled to produce a carbon fiber reinforced plastic.

[0004] Japanese Patent Application Laid-Open No. 2017-205878, Japanese Patent Application Laid-Open No. 2013-18859

[0005] However, since the fiber reinforced resin sheet described in Patent Document 1 has no cuts between the sheets, when springback occurs, the entire material swells uniformly. Therefore, springback cannot be suppressed.

[0006] In the invention described in Patent Document 2, a plurality of small pieces are laid out without gaps and directly molded without creating a plate-like composite material. Therefore, during molding, the resin flows outward around the small pieces, and a material with fibers oriented from the center of the small pieces to the outside is created. As a result, the molded body is likely to warp and twist. Also, when fluid molding is performed toward the outside of the aggregate of small pieces, the flow distance is long, and the tact time of molding becomes long.

[0007] The object of the present invention is to provide a manufacturing method that allows for the shortening of the molding cycle time when creating a plate-shaped composite material from multiple small pieces and then molding it, and that suppresses warping and twisting of the molded product.

[0008] As a result of diligent research, the inventors have found that the occurrence of welds can be suppressed by laminating at least one of the ends of multiple small pieces. Furthermore, they have found that springback can be suppressed by using multiple small pieces, and that molded articles having vertical surfaces can be easily formed. Specifically, they have found that the above problems can be solved by the means shown below, and have arrived at the present invention. 1. A method for producing a plate-shaped composite material by arranging multiple small pieces containing discontinuous reinforcing fibers and thermoplastic resin, heating and fusing them, wherein the produced plate-shaped composite material has a non-flow region which is the region where the small pieces are arranged before heating and melting, and a flow region which is the region other than the non-flow region, and the relationship between the total area Sa of the non-flow region and the total area Stotal of the plate-shaped composite material satisfies 0.4 × Stotal < Sa < 0.8 × Stotal. 2. The method for producing a composite material according to 1 above, wherein the average pixel value of the non-flow region measured in the following step is 0.95 × the average pixel value P of the entire composite material or less. Step 1. Step 1. Process the image data obtained from X-ray CT of the composite material to divide it into 256 pixel values ​​and calculate the average pixel value P of the entire composite material. Step 2. Divide the composite material into 1 mm × 1 mm sections. Step 3. In the image data, measure the pixel values ​​of each section and average 100 points to obtain the average pixel value of the non-flowing region. 3. A method for manufacturing a composite material according to 1 or 2 above, wherein the average thickness of the small pieces is Ty and the average thickness of the composite material is 0.9 × Ty or less. 4. A method for manufacturing a composite material according to any one of 1 to 3 above, wherein the small pieces are in the shape of a flat plate. 5. A method for manufacturing a composite material according to any one of 1 to 4 above, wherein the small pieces are recycled waste obtained by crushing a molded body containing discontinuous reinforcing fibers and thermoplastic resin.6. A method for manufacturing a composite material according to any one of 1 to 5, comprising the step of transporting the plurality of small pieces in an arranged state, heating and fusing them together to manufacture a plate-shaped composite material, wherein the plate-shaped composite material is an XY plane, the Y direction is the MD direction which is the direction in which the small pieces are transported, and the X direction is the TD direction which is perpendicular to the MD direction, and the flow distance when the small pieces are heated, melted and flowed is such that the flow distance in the X direction is less than the flow distance in the Y direction. 7. A method for manufacturing a plate-shaped composite material according to any one of 1 to 6, comprising the step of transporting the plurality of small pieces in an arranged state, heating and fusing them together to manufacture a plate-shaped composite material, wherein when the plate-shaped composite material is the XY plane, the Y direction is the MD direction which is the direction in which the small pieces are transported, and the X direction is the TD direction which is perpendicular to the MD direction, the relationship between the isotropy Iso(a) of the non-flowing region and the isotropy Iso(b2) of the flowing region in the Y direction of the non-flowing region satisfies Iso(a) < Iso(b2). 8. A method for manufacturing a molded article using a plate-shaped composite material obtained by the manufacturing method according to any one of 1 to 7, wherein the material is arranged such that the charge rate expressed by the following formula (3) is 50% or more. Charge rate (%) = 100 × Projection area of ​​the plate-shaped composite material (mm²). ２ ) / mold cavity area (mm²) ２) (3) 9. A method for producing a plate-shaped composite material by arranging a plurality of small pieces containing discontinuous reinforcing fibers and thermoplastic resin, heating and fusing them, wherein the weight-average fiber length Lw1 of the discontinuous reinforcing fibers is 5 mm or more, the discontinuous reinforcing fibers are randomly dispersed in the in-plane direction of the small pieces, and when the plurality of small pieces are arranged, the ends of the plurality of small pieces are stacked at least at one point. 10. The method for producing a plate-shaped composite material according to 9, wherein the ratio of the larger of the tensile modulus values ​​measured by tensile testing the plate-shaped composite material in two mutually orthogonal directions divided by the smaller value is 1.0 or more and 3.0 or less. 11. A method for manufacturing a plate-shaped composite material, comprising: a first component comprising a plurality of small pieces in which the first discontinuous reinforcing fibers are randomly dispersed in the in-plane direction, with the weight-average fiber length Lw1 being 5 mm or more; and a second component comprising a second discontinuous fiber having a weight-average fiber length Lw2 longer than Lw1, and a second thermoplastic resin; and a method for manufacturing a plate-shaped composite material by mixing these components and heating to melt-bond the first component and the second component. 12. A method for manufacturing a plate-shaped composite material, comprising: a first component comprising a plurality of small pieces in which the first discontinuous reinforcing fibers are randomly dispersed in the in-plane direction, with the weight-average fiber length Lw1 being 5 mm or more; and a second component comprising a second discontinuous fiber having a weight-average fiber length Lw2 longer than Lw1, and a second thermoplastic resin; and a method for manufacturing a plate-shaped composite material by laminating these components and heating to melt-bond the first component and the second component. 13. The method for manufacturing a plate-shaped composite material according to 9 or 10, wherein the small pieces form a post-molten hardened region in a plate-shaped composite material after melting, and N1 is the number of confoundings between discontinuous fibers in non-laminated regions where the post-molten hardened regions are not laminated with each other, and N2 is the number of confoundings between discontinuous fibers in laminated regions where the post-molten hardened regions are laminated with each other, such that N1 > N2.14. A method for producing a plate-shaped composite material according to any one of 9 to 13, comprising crushing a used molded body to obtain crushed material with a plate thickness tx, melting the crushed material and compressing it in the plate thickness direction to produce small pieces with a thickness ty smaller than tx.

[0009] In the manufacturing method of the present invention, a plate-shaped composite material is created by flowing a plurality of small pieces Xi. In the preferred method for manufacturing a molded article, the flow of the composite material during molding can be suppressed. This suppresses warping and twisting due to fiber orientation, and also shortens the cycle time during molding.

[0010] Furthermore, since a plate-shaped composite material is created without directly molding the small pieces Xi, the plate thickness can be easily designed. This is particularly effective when using recycled waste material R, which is expected to have non-uniform plate thickness, as the small pieces Xi.

[0011] A schematic diagram illustrating an example of each region of the plate-shaped composite material 101 of the first embodiment of the present invention. A schematic perspective view of a small piece 201. A schematic diagram showing a state in which a plurality of small pieces 201 are arranged to create a plate-shaped composite material 101. A schematic diagram showing a state in which at least a portion of a plurality of small pieces 201 are arranged in an overlapping state. A perspective view showing recycled waste material 301. A plan view showing the plate-shaped composite material 102 of the second embodiment. A cross-sectional view taken along the VII-VII line in Figure 6. A schematic perspective view of a small piece Ai. A diagram showing a state in which springback 105 has occurred in the composite material 102. A diagram showing a state in which the plate-shaped composite material 102 with springback 105 has occurred is placed between the upper molding die 502 and the lower molding die 503.

[0012] [First Embodiment] Figure 1 is a schematic diagram illustrating an example of each region of a plate-shaped composite material 101 according to the first embodiment of the present invention. The composite material 101 is obtained by arranging a plurality of small pieces 201 and fusing them together by heating and melting them.

[0013] The small piece 201 is preferably a flat plate shape as shown in Figure 2. Using a flat plate-shaped small piece 201 allows for easy melting and flow. As shown in Figure 3, it is preferable that multiple small pieces 201 are arranged as an aggregate. It is preferable to prepare at least two or more small pieces 201 and heat and melt them to make them flow. Alternatively, as shown in Figure 4, multiple small pieces 201 may be arranged with at least some overlapping. The small piece 201 contains a first discontinuous reinforcing fiber and a first thermoplastic resin.

[0014] [Discontinuous Reinforcing Fibers] The reinforcing fibers contained in the small piece 201 are preferably at least one selected from the group consisting of carbon fibers, aramid fibers, and glass fibers. More preferably, the reinforcing fibers are carbon fibers or glass fibers.

[0015] [Discontinuous Reinforcement Fibers: Carbon Fibers] 1. General Carbon Fibers When using carbon fibers, polyacrylonitrile (PAN) carbon fibers, petroleum / coal pitch carbon fibers, rayon carbon fibers, cellulose carbon fibers, lignin carbon fibers, phenolic carbon fibers, etc. are generally known, but in the present invention, any of these carbon fibers can be suitably used. Among them, in the present invention, it is preferable to use polyacrylonitrile (PAN) carbon fibers because they have excellent tensile strength. As a PAN carbon fiber, for example, Teijin Limited's carbon fiber "Tenax" (registered trademark) STS40-24KS (average fiber diameter 7 μm) can be used.

[0016] 2. The carbon fibers used in the carbon fiber sizing agent pieces 201 may have the sizing agent attached to their surface. When using carbon fibers with the sizing agent attached, the type of sizing agent can be appropriately selected according to the type of carbon fiber and the type of resin, and is not particularly limited.

[0017] [Discontinuous Reinforcing Fibers: Glass Fibers] This section describes the case where glass fibers are used as reinforcing fibers in small piece 201. 1. Glass Fibers in General Any glass fiber that is generally referred to as glass fiber may be used in small piece 201. The glass composition is not particularly limited to A glass, C glass, E glass, etc., and TiO may be used depending on the case. ２ , P ２ O ５ It may also contain components such as the above. As for glass fibers, for example, Nitto Boseki's glass fiber E-glass RS240QR-483 (count: 2400g / 1000m) can be used.

[0018] 2. The glass fibers used in the glass fiber sizing agent pieces 201 may have a sizing agent attached to their surface. When using glass fibers with a sizing agent attached, the type of sizing agent can be appropriately selected according to the type of glass fiber and the type of resin, and is not particularly limited. Preferably, glass fibers that have been pre-treated with conventionally known coupling agents such as organosilane compounds, organotitanium compounds, organoborane compounds, and epoxy compounds can be used.

[0019] Since the weight-average fiber length of the discontinuous reinforcing fibers does not change before and after molding, the weight-average fiber length Lw of the discontinuous reinforcing fibers contained in the composite material can be determined by examining the weight-average fiber length of the discontinuous reinforcing fibers in the molded product.

[0020] The weight-average fiber length Lw of the discontinuous reinforcing fibers is preferably 1 mm or more, and more preferably 3 mm or more. More preferably the weight-average fiber length Lw of the discontinuous reinforcing fibers is 3 mm or more and 100 mm or less, more preferably 3 mm or more and 80 mm or less, and even more preferably 5 mm or more and 60 mm or less. If the weight-average fiber length Lw of the discontinuous reinforcing fibers is 100 mm or less, the fluidity of the composite material is less likely to decrease when the composite material is manufactured by compression molding, making it easier to create the desired shape. Also, if the weight-average fiber length Lw is 1 mm or more, the mechanical strength of the resulting molded article is less likely to decrease, which is preferable.

[0021] The weight-average fiber length Lw and number-average fiber length Ln of the discontinuous reinforced fiber can be calculated using equations (1) and (2) described below.

[0022] In the present invention, discontinuous reinforcing fibers having different fiber lengths may be used in combination. In other words, the discontinuous reinforcing fibers used in the present invention may have a single peak in the weight-average fiber length distribution, or they may have multiple peaks.

[0023] [Number-average fiber length Ln and weight-average fiber length Lw] Generally, if the fiber length of each discontinuous reinforcing fiber is Li, the number-average fiber length Ln and the weight-average fiber length Lw can be calculated using the following equations (1) and (2). Note that the units of the number-average fiber length Ln and the weight-average fiber length Lw are mm.

[0024] Here, "I" indicates the number of discontinuous reinforcing fibers measured.

[0025] When the fiber length is constant, the number-average fiber length and the weight-average fiber length will be the same value. Discontinuous reinforcing fibers can be extracted from a molded body by, for example, applying a heat treatment of approximately 650°C for 3 hours and removing the resin in the furnace.

[0026] The average fiber length can be determined, for example, by measuring the fiber length of 100 discontinuous reinforcing fibers randomly selected from the molded body to the nearest 1 mm using a caliper or similar device, and then calculating it based on formula (1) or formula (2).

[0027] If the material contains discontinuous reinforcing fibers less than 1 mm in length that cannot be measured with calipers, the resin is removed, and the resulting reinforcing fibers are placed in water containing a surfactant and thoroughly stirred using ultrasonic vibration. A random sample of the stirred dispersion is taken using a measuring spoon to obtain an evaluation sample, and the length of 3000 fibers is measured using a Luzex AP image analysis device manufactured by Nireco. Using the measured fiber lengths, the number-average fiber length Ln and the weight-average fiber length Lw can be determined in the same manner as in equations (1) and (2) described above.

[0028] [Reinforcement Fibers: Single Yarn Ratio] When reinforcement fibers with a bundle width of 0.3 mm or less are defined as single yarns, and reinforcement fibers with a bundle width exceeding 0.3 mm are defined as fiber bundles, the ratio of single yarns with a bundle width of 0.3 mm or less to the total reinforcement fibers (single yarn ratio = mass of single yarns / (mass of single yarns + mass of fiber bundles)) is preferably 1% or more and 90% or less, more preferably 1% or more and 50% or less, even more preferably 1% or more and 25% or less, and even more preferably 1% or more and 20% or less. In this specification, weight can also be said to be mass.

[0029] [Thermoplastic Resin] The type of thermoplastic resin contained in the small piece 201 is not particularly limited, and one having a desired softening point or melting point can be appropriately selected and used. As the thermoplastic resin, one with a softening point in the range of 180°C to 350°C is usually used, but it is not limited to this.

[0030] Examples of thermoplastic resins include polyolefin resins, polystyrene resins, polyamide resins, polyester resins, polyacetal resins (polyoxymethylene resins), polycarbonate resins, (meth)acrylic resins, polyarylate resins, polyphenylene ether resins, polyimide resins, polyethernitrile resins, phenoxy resins, polyphenylene sulfide resins, polysulfone resins, polyketone resins, polyetherketone resins, thermoplastic urethane resins, fluoropolymer resins, thermoplastic polybenzimidazole resins, and the like.

[0031] The thermoplastic resin contained in the small piece 201 may be of one type or two or more types. Examples of using two or more types of thermoplastic resins in combination include, but are not limited to, using thermoplastic resins with different softening points or melting points, or using thermoplastic resins with different average molecular weights.

[0032] When using thermoplastic resins, it is preferable to use polyamide or polyolefin resins, and more preferable to use polypropylene resins.

[0033] [Other Agents] Small piece 201 may contain additives such as various fibrous or non-fibrous fillers of organic or inorganic fibers other than the reinforcing fibers described in the present invention, flame retardants, UV resistant agents, stabilizers, mold release agents, pigments, softeners, plasticizers, and surfactants, to the extent that the objectives of the present invention are not impaired. One type of additive may be used alone, or two or more types may be used in combination.

[0034] The discontinuous reinforcing fibers contained in the small piece 201 are preferably randomly dispersed in the in-plane direction of the small piece 201. The small piece 201 of the present invention is preferably plate-shaped. The XY plane of the plate-shaped small piece 201 is one of the basic two-dimensional planes in three-dimensional space. This plane is defined by the X and Y axes and is located perpendicular to the Z axis. The XY plane is, for example, the XY direction in Figure 2.

[0035] The discontinuous reinforcing fibers contained in the small piece 201 are randomly dispersed in the in-plane direction. Dispersion of discontinuous reinforcing fibers in the in-plane direction means that the fiber axes of the reinforcing fibers are oriented in the in-plane direction. Preferably, the angle that the fiber axes of the discontinuous reinforcing fibers make with the in-plane direction is 45° or less.

[0036] Furthermore, it is more preferable that the discontinuous reinforcing fibers are randomly dispersed in a two-dimensional direction in the in-plane direction. Two-dimensional random dispersion means that the discontinuous reinforcing fibers are oriented in a disordered manner in the in-plane direction of the small piece 201, rather than in a specific direction such as one direction, and are arranged in the XY plane without showing a particular direction overall.

[0037] The in-plane direction of the small piece 201 is the direction perpendicular to the thickness direction (XY direction in Figure 2). While the longitudinal direction and width direction refer to fixed directions, the in-plane direction refers to an indeterminate direction on the same plane (parallel planes perpendicular to the thickness direction). By dispersing the discontinuous reinforcing fibers of the small piece 201 in the in-plane direction, it becomes easier to disperse them in the in-plane direction even in plate-shaped composite materials.

[0038] There is no particular limitation on the fiber volume fraction Vf of the discontinuous reinforcing fibers in the small piece 201, but 20 to 70% is preferable, 25 to 60% is more preferable, and 30 to 55% is even more preferable. Note that the fiber volume fraction (Vf unit: volume %) is the ratio of the volume of the discontinuous reinforcing fibers to the total volume including not only the discontinuous reinforcing fibers and the resin but also other additives and the like.

[0039] [Recycled crushed material] A used molded body may be crushed to take out a recycled crushed material, and this may be used as the small piece 201. The recycled crushed material may be a material obtained by crushing a crushed material or a scrap generated in the manufacturing process of the composite material or at the stage of molding the composite material, or a molded body recovered after once being circulated in the market. For crushing, there are methods such as crushing with a commercially available crusher or cutting the composite material using a cutting machine, and a recycled crushed material can be obtained thereby. By using the recycled crushed material, the manufacturing cost can be reduced, and it can contribute to resource saving and global environmental conservation.

[0040] When a molded body recovered after once being circulated in the market is crushed to obtain a recycled crushed material, if it has been shaped and has a shape, it is advisable to heat it once to return it to a flat state. If the shape is flat, it can be used as the small piece 201 as it is. When a molded body recovered after once being circulated in the market is crushed to obtain a recycled crushed material, its size will be not larger than the size of the recovered molded body. The size of the recycled crushed material is preferably 15 mm × 15 mm or more and 300 mm × 300 mm or less, and more preferably 20 mm × 20 mm or more and 200 mm × 200 mm or less.

[0041] Also, the plate thickness of the recycled crushed material is not necessarily the same, and a non-uniform case is also assumed. According to the manufacturing method of the present invention, even for a recycled crushed material having such a non-uniform thickness, the plate thickness can be easily controlled by creating a plate-shaped composite material once.

[0042] Alternatively, recycled waste material may be melted and compressed in the plate thickness direction to produce small pieces 201. FIG. 5 is a perspective view showing the recycled waste material 301. In this embodiment, a used molded body is crushed to take out recycled waste material 301 with a plate thickness tx, the recycled waste material 301 is melted and rolled in the plate thickness direction, and it is preferable to produce small pieces 201 with a plate thickness ty as shown in FIG. 2. However, tx > ty. Here, when the plate thickness of the small pieces 201 is not uniform, it is preferable to use the average value of the plate thickness as ty and satisfy tx > ty.

[0043] That is, it is preferable that the plate thickness ty of the small pieces 201 is thinner than the plate thickness tx of the recycled waste material 301. To satisfy tx > ty, the recycled waste material 301 may be melted and compressed in the plate thickness direction to produce small pieces 201. By thinning the plate thickness of the recycled waste material 301 and using it as small pieces 201, it becomes easier to form it into a desired molding thickness.

[0044] When rolling the recycled waste material 301 to create small pieces 201, the rolling ratio is represented by the following formula. Rolling ratio (%) = (1 - ty / tx) × 100 The rolling ratio (%) is preferably 1% or more and 90% or less, more preferably 20% or more and 85% or less, and even more preferably 45% or more and 80% or less.

[0045] When the rolling ratio increases, in the process of producing small pieces 201 from the recycled waste material, the bundles of reinforcing fibers open. When obtaining a molded body from the obtained small pieces 201, when evaluating the molded body with the same plate thickness, if the bundle width of the reinforcing fibers contained in the small pieces 201 increases, the physical properties of impact resistance are improved and the crack generation ratio decreases, which is preferable.

[0046] There is no particular limitation on the size of the small pieces 201, but the thickness ty of the small pieces 201 is preferably 0.1 mm or more and 10 mm or less, more preferably 0.2 mm or more and 5 mm or less, and even more preferably 0.3 mm or more and 3 mm or less.

[0047] Furthermore, when recycled waste material 301 is rolled to create small pieces 201, they often take on a roughly elliptical shape. The size of the roughly elliptical small pieces 201 is preferably measured by its major axis and minor axis. The major axis × minor axis of the roughly elliptical small pieces 201 is preferably 15 mm × 10 mm or more and 600 mm × 500 mm or less, more preferably 20 mm × 15 mm or more and 400 mm × 300 mm or less, even more preferably 25 mm × 20 mm or more and 300 mm × 200 mm or less, and even more preferably 30 mm × 25 mm or more and 100 mm × 80 mm or less.

[0048] The term "approximately elliptical shape" includes shapes that are not perfect ellipses but are nearly elliptical. Examples include nearly elliptical circles (not perfect circles, but slightly elongated vertically or horizontally), nearly elliptical rectangles (rectangles with rounded corners), and nearly elliptical triangles (triangles with rounded corners). It also includes shapes where the arc of the ellipse is wavy, saw-toothed, or similarly irregular. Furthermore, since it is preferable to create small pieces 201 by rolling the recycled waste material 301, it is preferable that the area of ​​the small pieces 201 is larger than that of the recycled waste material 301.

[0049] As shown in Figure 1, the composite material 101 has a non-flowing region A and flowing regions B1 to B3. Non-flowing region A corresponds to the region where multiple small pieces are arranged before heating and melting. Flowing regions B1 to B3 are regions formed by the thermoplastic resin and discontinuous reinforcing fibers that flowed from non-flowing region A after the small pieces placed in non-flowing region A melted. Here, the X and Y directions in Figure 1 are mutually perpendicular in-plane directions of the plate-shaped composite material 101. For example, in the case of a composite material 101 made using a double belt, the Y direction is called the MD direction (Machine Direction), which is the direction of transporting the small pieces, and the X direction is called the TD direction (Transverse Direction), which is perpendicular to the transport direction. The flowing region B in the X direction of non-flowing region A is called flowing region B1, and the flowing region B in the Y direction of non-flowing region A is called flowing region B2. In addition, the flowing regions other than flowing region B1 and flowing region B2 are called flowing region B3.

[0050] The relationship between the isotropy Iso(a) of the non-flowing region A and the isotropy Iso(b2) of the flowing region B2 preferably satisfies Iso(a) < Iso(b2). Iso(a) is preferably greater than 1.0 and 1.5 or less, more preferably greater than 1.1 and 1.4 or less, and even more preferably greater than 1.2 and 1.3 or less. Iso(b2) is preferably greater than 1.2 and 1.8 or less, more preferably greater than 1.3 and 1.6 or less, and even more preferably greater than 1.4 and 1.5 or less.

[0051] The isotropy Iso(a) of the non-flowing region A and the isotropy Iso(b2) of the flowing region B2 are evaluated by determining the ratio of the tensile moduli in two mutually orthogonal directions. Specifically, specimens are cut from the non-flowing region A and the flowing region B2, and the tensile moduli are measured in an arbitrary direction of the specimen and in a direction perpendicular to it. The ratio (Eδ) obtained by dividing the larger of the two values ​​of tensile moduli in the arbitrary direction and in the direction perpendicular to the arbitrary direction of the specimen by the smaller value is taken as the value of isotropy Iso.

[0052] In this invention, the composite material is a material for creating a molded body, and the composite material is compression molded to form a molded body. Therefore, although the composite material in this invention is in the shape of a flat plate, the molded body is shaped and has a three-dimensional shape. When evaluating the isotropy Iso of a molded body including a three-dimensional shape, the evaluation can be performed using the flat composite material that has been solidified after being heated above the softening temperature to return the molded body to a flat plate shape.

[0053] The isotropy Iso(a) of non-flowing region A can be described as the degree of orientation, indicating how much the reinforcing fibers are dispersed randomly in two dimensions within non-flowing region A. The isotropy Iso(a) of non-flowing region A is between 1.0 and 5, preferably between 1.0 and 3.0, more preferably between 1.0 and 2.0, and even more preferably between 1.0 and 1.5. The closer the value of isotropy Iso(a) is to 1.0, the more the reinforcing fibers are evaluated to be dispersed randomly in two dimensions.

[0054] The isotropy of the composite material 101 as a whole is preferably 1.0 to 3.0. More preferably 1.1 to 2.0, and even more preferably 1.1 to 1.5.

[0055] There are no particular limitations on the thickness of the small pieces 201, but it is preferably 0.1 mm to 10 mm, more preferably 0.2 mm to 5 mm, and even more preferably 0.3 mm to 3 mm. If the average thickness of the small pieces Xi is Ty, a composite material with a thickness of 0.9 × Ty or less can be manufactured by arranging multiple small pieces Xi, then heating and melting the small pieces Xi to allow them to flow. More preferably, the thickness of the composite material 101 is 0.8 × Ty or less, and even more preferably the thickness of the composite material is 0.7 × Ty or less. The thickness of the plate-shaped composite material 101 is preferably in the range of 0.5 mm to 8.0 mm, and more preferably in the range of 0.5 mm to less than 2.0 mm. In this way, by creating a plate-shaped composite material by reducing the thickness of the small pieces 201, the plate thickness of the composite material and molded body can be easily controlled.

[0056] Figure 3 schematically shows the state of the multiple small pieces 201 before they are melted and made to flow. The multiple small pieces 201 melt and combine to form the plate-shaped composite material 101 shown in Figure 1. The areas where the small pieces 201 are arranged form non-flowing regions A when the composite material is formed.

[0057] In Figure 3, when multiple small pieces 201 are arranged, there are spaces 402 where the small pieces 201 are not laid. When the small pieces 201 melt, the thermoplastic resin and reinforcing fibers flow to fill these spaces 402, and as shown in Figure 1, flow regions B1 to B3 that fill the spaces 402 are formed. Alternatively, as shown in Figure 4, multiple small pieces 201 may be arranged with at least some overlapping. Even in this arrangement, there are spaces 402 where the small pieces 201 are not laid. When the small pieces 201 melt, the thermoplastic resin and reinforcing fibers flow to fill these spaces 402, and flow regions that fill the spaces 402 are formed.

[0058] The relationship between the total area Sa of non-flowing region A and the total area Stotal of the plate-shaped composite material 101 satisfies 0.4 × Stotal < Sa < 0.8 × Stotal. In other words, the material is made to flow such that the relationship between the total area Sa of non-flowing region A and the total area Stotal of non-flowing region A and flowing regions B1 to B3 satisfies 0.4 × Stotal < Sa < 0.8 × Stotal.

[0059] The upper limit of the total area Sa of the non-flowing region A is preferably Sa < 0.7 × Stotal, and more preferably Sa < 0.6 × Stotal. By satisfying Sa < 0.8 × Stotal, when creating a plate-shaped composite material of the desired size, it is possible to prevent the small pieces 201 from melting and flowing to the outside of the plate-shaped composite material, which would otherwise exceed the desired size.

[0060] On the other hand, the lower limit of the total area Sa of the non-flow region A is preferably 0.45 × Stotal < Sa, and more preferably 0.5 × Stotal < Sa. By setting it within this range, it is possible to suppress the situation in which there is a shortage of small pieces 201 and it becomes impossible to form a plate-shaped composite material.

[0061] It is preferable that the average pixel value of the non-flowing region A measured in the following steps is 0.95 × the average pixel value P of the entire composite material or less. Step 1. Process the image data obtained from X-ray CT of the composite material to divide it into 256 pixel values ​​and calculate the average pixel value P of the entire composite material. Step 2. Divide the composite material into 1 mm × 1 mm sections. Step 3. In the image data, measure the pixel value of each section and average 100 points to obtain the average pixel value of the non-flowing region A.

[0062] Here, a larger pixel value in the image data obtained by X-ray CT indicates greater X-ray absorption. The higher the density of the material contained in the composite material, the greater the X-ray absorption. When the reinforcing fiber is carbon fiber, its density is higher than that of thermoplastic resin, resulting in greater X-ray absorption. Therefore, the more carbon fiber a region contains, the larger the pixel value of the image data. When the reinforcing fiber is glass fiber, the silicon atoms contained in the glass absorb more X-rays. Therefore, the more glass fiber a region contains, the larger the pixel value of the image data.

[0063] In step 1, it is preferable that the 256 pixel values ​​are 8-bit grayscale.

[0064] Non-flowing region A has a concentrated arrangement of reinforcing fibers, resulting in 256 higher pixel values ​​compared to flowing region B.

[0065] By ensuring that the average pixel value of the non-flowing region A is less than or equal to 0.95 × the average pixel value P of the entire composite material, it is possible to prevent the plate-shaped composite material from becoming larger than the desired size and causing small pieces 201 to melt and flow outside the plate-shaped composite material when creating a plate-shaped composite material of the desired size.

[0066] If P is the average pixel value of the image data obtained by X-ray CT of the entire composite material, the lower limit of the average pixel value of the non-flowing region A is preferably 0.75 × P or higher, and more preferably 0.8 × P or higher.

[0067] [Plate-shaped composite material] 1. Shape The composite material of the present invention is plate-shaped. Plate-shaped means that when the composite material has its largest surface area (maximum surface) and the opposite surface (which may have the same area as the maximum surface or a smaller area than the maximum surface; hereinafter referred to as the quasi-maximum surface), with one of these surfaces being the top surface and the other the bottom surface, the thickness dimension when the composite material is viewed from the horizontal is smaller than the width dimension and depth dimension when the composite material is viewed from directly above in the vertical direction (thickness direction).

[0068] Furthermore, some thickness dimensions may be greater than the width and depth dimensions. A plate-shaped composite material may have some steps or inclines in its shape (thickness shape) when viewed from the horizontal in the above-mentioned holding state. Examples of such steps or inclines include those where the ratio of the thickness of the thickest part to the thinnest part is greater than 1 and 5 or less, and more preferably greater than 1 and 3 or less. A plate-shaped composite material may also be a curved plate. A typical plate-shaped composite material has a rectangular shape when viewed in the thickness direction in the above-mentioned holding state, but the shape may also be a polygon, circular, or irregular shape other than a rectangle.

[0069] It is more preferable that the composite material be in the form of a flat plate. A flat plate means that, in the above-mentioned holding state, the shape when viewed from the horizontal direction is flat, that is, there are no obvious steps or changes in thickness of more than twice as much, which is preferable because it has many applications and is easy to mold. In the case of a flat plate composite material with substantially uniform thickness, the spraying angle can also be expressed as the angle with respect to the horizontal plane at the center of the plate thickness. 2. Relationship between plate-shaped composite material and molded body In the present invention, the plate-shaped composite material is a material for creating a molded body, and the plate-shaped composite material is compression-molded to become a molded body. Therefore, although the composite material in the present invention is in the form of a plate, the molded body is shaped and has a three-dimensional shape. In the region where the plate-shaped composite material is compression-molded without flowing, the shape of the reinforcing fibers is almost maintained before and after molding.

[0070] [Sheet-shaped composite material: Dispersion in the in-plane direction] The reinforcing fibers contained in the non-flow region A are discontinuous fibers and are preferably dispersed in the in-plane direction of the composite material. Furthermore, dispersing the reinforcing fibers contained in the composite material in the in-plane direction makes it easier to disperse them in the in-plane direction in the molded article as well. Dispersion of reinforcing fibers in the in-plane direction means that the fiber axes of the reinforcing fibers are oriented in the in-plane direction. It is preferable that the angle that the fiber axes of the reinforcing fibers make with the in-plane direction is 45° or less. The in-plane direction is an indeterminate direction of parallel planes perpendicular to the thickness direction of the composite material or molded article. The composite material is a sheet-shaped material, and the in-plane direction is also the XY plane direction.

[0071] [Random dispersion in two dimensions] It is preferable that the reinforcing fibers are randomly dispersed in two dimensions in the in-plane direction. In regions where the composite material is compression-molded without flowing, the shape of the reinforcing fibers is largely maintained before and after molding. In particular, in non-flowing region A, it is preferable that the fibers remain randomly dispersed in two dimensions in the in-plane direction even when the composite material becomes a plate-like or molded body.

[0072] Here, "randomly dispersed in two dimensions" means that the reinforcing fibers are oriented in a disordered manner within the in-plane direction of the composite material, rather than in a specific direction such as one direction, and are arranged within the sheet surface without exhibiting a particular direction overall.

[0073] [Reinforcement Fibers: Fiber Volume Ratio] There are no particular limitations on the fiber volume ratio Vf of the reinforcement fibers, but the fiber volume ratio Vf in the non-flowing region A is preferably 20% to 60%, more preferably 25% to 55%, and even more preferably 30% to 45%. On the other hand, the fiber volume ratio Vf in the flowing region B is preferably 10% to 50%, more preferably 15% to 40%, and even more preferably 20% to 35%. In other words, the fiber volume ratio Vf in the flowing region B is preferably 5% to 10% lower than the fiber volume ratio Vf in the non-flowing region A. Note that the fiber volume ratio (Vf, unit: volume%) is the ratio of the volume of reinforcement fibers to the total volume, which includes not only the reinforcement fibers and resin, but also other additives, etc. There are no particular limitations on the fiber volume ratio Vf of the entire composite material, but it is preferably 20 to 70%, more preferably 25 to 60%, and even more preferably 30 to 55%.

[0074] While there are no specific methods for analyzing the volume ratio of reinforcing fibers, it is recommended to measure it as follows: Cut a sample from the molded body, burn off the resin in a furnace at 650°C for 3 hours, and weigh the sample before and after treatment to calculate the mass of reinforcing fibers, resin, and other additives. Next, use the specific gravity of each component to calculate the volume ratio of reinforcing fibers to resin: Vf = 100 × volume of reinforcing fibers / (volume of reinforcing fibers + volume of resin + other additives)

[0075] [Manufacturing Method: Melting and Flowing] Various methods can be used to melt and flow the small pieces 201. The manufacturing method for the composite material 101 may be a batch method in which the small pieces 201 are melted and flowed in a mold to obtain a plate-shaped composite material 101, or a method for manufacturing a continuous plate-shaped composite material. Manufacturing a continuous plate-shaped composite material is preferable from the viewpoint of productivity. Even when manufacturing a continuous plate-shaped composite material, the arrangement of the small pieces 201 is discontinuous.

[0076] [Manufacturing Example 1] When the small piece 201 is of a predetermined size, a compression device (press device) can be used. Specifically, the composite composition is placed between a pair of upper and lower pressing surfaces of the compression device, heated, and the pair of pressing surfaces are brought closer together to thin the thickness of the small piece 201 and make it flow, thereby manufacturing the composite material. Alternatively, a plate-shaped composite material may be manufactured by compression molding using upper and lower molding dies.

[0077] [Manufacturing Example 2] Small pieces 201 can be arranged on a moving body such as a belt, and moved in the Machine Direction (MD direction). A mold (device to increase bulk density) can be used in which the spacing between the pieces narrows as the movement moves from the upstream side to the downstream side in the MD direction. Specifically, by moving (passing) the small pieces 201 from the upstream side to the downstream side between the molds with narrowing spacing, the thickness of the small pieces 201 is reduced and they become fluid, making it possible to manufacture a composite material having a non-fluid region A and a fluid region B. As a method for moving the discontinuously arranged small pieces 201, for example, a conveyor system can be used in which the small pieces 201 placed on the moving body pass between the molds together with the moving body.

[0078] [Manufacturing Example 3] When small pieces 201 are arranged on a moving body and fed in continuously, a pair of rollers (considered as one set) with adjusted spacing can be used. For example, by moving multiple small pieces 201 and passing them between at least one set of rollers, the thickness of the small pieces 201 is reduced and they flow, thereby manufacturing a composite material having a non-flowing region A and a flowing region B. When using multiple sets of rollers, the sets of rollers may be arranged such that the spacing between the pairs of rollers narrows as the small pieces 201 move from the upstream side to the downstream side in the direction of movement.

[0079] [Manufacturing Example 4] When small pieces 201 are lined up and fed continuously, a pair of belts with adjusted spacing can be used (a so-called double belt press method). By passing the small pieces 201 between belts arranged so that the belt spacing narrows as the pair of belts move from the upstream side to the downstream side where they face each other, the thickness of the small pieces 201 is reduced and made to flow, thereby manufacturing a composite material having a non-flowing region A and flowing regions B1 to B3. The belt spacing can be adjusted using rollers or support plates placed on the back side of the belts.

[0080] [Other] In the above manufacturing examples 1 to 4, for example, a compression device, mold, roller, belt, etc. equipped with a heating means for heating the small pieces 201 during compression can be used.

[0081] [Flow distance when small piece 201 is heated, melted, and made to flow] When a plate-shaped composite material is considered as an XY plane, with the X direction being the TD direction and the Y direction being the MD direction, it is preferable that the flow distance when small piece 201 is heated, melted, and made to flow is less than the flow distance in the Y direction. That is, it is preferable that the flow distance in the TD direction is less than the flow distance in the MD direction. For example, when a composite material is made using a double belt, the clearance narrows toward the MD direction (downstream side), making it easier to flow in the Y direction (MD direction), which is preferable from the viewpoint of productivity. Therefore, it is preferable that the flow distance in flow region B1 is less than the flow distance in flow region B2.

[0082] [Method for Manufacturing Molded Articles: Compression Molding] 1. Hot Press Molding and Cold Press Molding When creating molded articles, composite materials can be manufactured by compression molding (sometimes called press molding), and compression molding methods such as hot press molding and cold press molding can be used. By compression molding composite materials, various shapes can be imparted to the molded articles. 2. Cold Press Molding In the cold press molding method, for example, a composite material heated to a first predetermined temperature is placed into a mold set to a second predetermined temperature, and then pressurized and cooled.

[0083] Specifically, if the thermoplastic resin contained in the small piece 201 is crystalline, the first predetermined temperature is above the melting point, and the second predetermined temperature is below the melting point. If the thermoplastic resin is amorphous, the first predetermined temperature is above the glass transition temperature, and the second predetermined temperature is below the glass transition temperature. In other words, the cold press method includes at least the following steps A-1) to A-2). Step A-1) A step of heating the thermoplastic resin to a temperature above the melting point and below the decomposition temperature if it is crystalline, and above the glass transition temperature and below the decomposition temperature if it is amorphous. Step A-2) A step of placing the composite material heated in step A-1) into a mold whose temperature is controlled to below the melting point if the thermoplastic resin is crystalline, and below the glass transition temperature if it is amorphous, and applying pressure. By performing these steps, the molding of the composite material can be completed.

[0084] The above steps must be performed in the order specified above, but other steps may be included between them. Other steps include, for example, a forming step before step A-2) in which a different forming die from the one used in step A-2) is used to pre-form the shape of the cavity of the forming die. The shape of the composite material may be a shape developed from the three-dimensional shape of the compression molded product to be manufactured by reverse forming analysis using a computer.

[0085] 3. Hot Press Molding The hot press molding method involves, for example, placing a composite material into a mold, increasing the temperature of the mold to a first predetermined temperature while applying pressure, and then cooling the mold to a second predetermined temperature. Specifically, if the thermoplastic resin contained in the small piece 201 is crystalline, the first predetermined temperature is above the melting point, and the second predetermined temperature is below the melting point. If the thermoplastic resin contained in the small piece 201 is amorphous, the first predetermined temperature is above the glass transition temperature, and the second predetermined temperature is below the glass transition temperature. Hot press molding preferably includes at least the following steps B-1) to B-4). B-1) A step of placing the composite material in a mold (second mold, lower mold). B-2) A step of heating the mold and applying pressure (first press step) to a temperature above the melting point of the thermoplastic resin but below the thermal decomposition temperature if the thermoplastic resin is crystalline, or above the glass transition temperature of the thermoplastic resin but below the thermal decomposition temperature if the thermoplastic resin is amorphous. B-3) A step (second pressing step) in which pressure is applied in one or more stages, such that the pressure in the final stage is between 1.2 and 100 times the pressure in the first pressing step. B-4) A step to adjust the mold temperature so that it is below the melting point if the thermoplastic resin is crystalline, or below the glass transition temperature if it is amorphous. By performing these steps, an integrally molded structure can be created.

[0086] 4. Common aspects of cold press molding and hot press molding Steps A-2) and B-3) are steps in which pressure is applied to the composite material to obtain a molded body of the desired shape. There are no particular limitations on the molding pressure at this time, but it is preferable to keep it as low as possible within the range in which the desired molded body shape can be obtained. Specifically, it is preferable that the molding pressure be less than 30 MPa relative to the projected area of ​​the mold cavity, more preferably 20 MPa or less, and even more preferably 10 MPa or less. When the molding pressure is less than 30 MPa, it is preferable because it does not require capital investment or maintenance costs for the press machine. Also, naturally, various steps may be inserted between the above steps during compression molding, for example, vacuum compression molding, which is compression molding while under vacuum, may be used.

[0087] 5. Charge Rate When forming a molded body using the plate-shaped composite material of the present invention, it is preferable to arrange the material so that the charge rate, expressed by the following formula (3), is 50% or more. Charge rate (%) = 100 × Projection area of ​​the plate-shaped composite material (mm²) ２ ) / mold cavity area (mm²) ２ (3) A preferred charge rate is 60% or more, and a more preferred charge rate is 80%. The plate-shaped composite material of the present invention has a non-flowing region A and a flowing region B, and a portion of it is already flowing. By reducing the flow during press molding and setting the charge rate within the above range, the flow during molding is suppressed.

[0088] [Second Embodiment] Figure 6 is a plan view showing a plate-shaped composite material 102 according to the second embodiment of the present invention. In the composite material 102, the post-molten hardened regions Di formed by the melting and hardening of small pieces Ai (where i is a natural number from 1 to n), which will be described later, overlap and fuse together at the edges. In Figure 6, n = 6, and the post-molten hardened regions D1 to D6 overlap in the laminated region 103. For example, the post-molten hardened region D2 overlaps with the post-molten hardened regions D1, D3, D4, D5, and D6.

[0089] Figure 7 is a cross-sectional view taken along the line VII-VII in Figure 6. As shown in Figure 7, regions D5 and D6 are melted and joined together, overlapping each other vertically at their edges.

[0090] In the method for manufacturing the plate-shaped composite material in the second embodiment, a plurality of small pieces Ai (where i is a natural number from 1 to n) as shown in Figure 8 are prepared, and the ends of the small pieces Ai are arranged so that they have a plan view similar to Di shown in Figure 6, with the Ai overlapping at least in one place, and then the mixture is heated to melt and bond the plurality of small pieces Ai together.

[0091] The shape of the small piece Ai is preferably a flat plate shape as shown in Figure 8. By using flat plate-shaped small pieces Ai, the small pieces Ai can be easily melt-bonded together. The XY plane of the flat plate-shaped small piece Ai is one of the basic two-dimensional planes in three-dimensional space. This plane is defined by the X and Y axes and is located perpendicular to the Z axis.

[0092] The small piece Ai contains discontinuous reinforcing fibers and a thermoplastic resin. The thermoplastic resin contained in the small piece Ai is the same as the thermoplastic resin used in the small piece 201 of the first embodiment.

[0093] The discontinuous reinforcing fibers contained in the small piece Ai are the same as the discontinuous reinforcing fibers used in the small piece 201 of the first embodiment. The weight-average fiber length Lw1 of the discontinuous reinforcing fibers is preferably 5 mm or more. Furthermore, it is preferable that the discontinuous reinforcing fibers are dispersed randomly in two dimensions in the in-plane direction of the small piece Ai. Dispersion in the in-plane direction means that the fiber axes of the discontinuous reinforcing fibers are dispersed so as to face the in-plane direction of the small piece Ai. It is preferable that the angle that the fiber axes of the discontinuous reinforcing fibers make with the in-plane direction is 45° or less. Random dispersion in two dimensions means that the discontinuous reinforcing fibers are oriented disorderly rather than in a specific single direction in the in-plane direction of the small piece Ai, and are arranged in the plane without showing a specific direction overall. While the longitudinal direction and width direction refer to a fixed direction, the in-plane direction refers to an unspecified direction in a plane perpendicular to the thickness direction of the small piece Ai, the composite material 102, or the molded body formed from the composite material 102. Specifically, this refers to the direction within the XY plane in Figure 8. By dispersing the first discontinuous reinforcing fibers within the small piece Ai in the in-plane direction, it becomes easier to disperse the first discontinuous reinforcing fibers in the in-plane direction even in the plate-shaped composite material 102.

[0094] The isotropy IsoAi of the small piece Ai can be described as the degree of orientation, which indicates how much the first discontinuous reinforcing fibers are dispersed randomly in two dimensions. The isotropy IsoAi of the small piece Ai is preferably between 1.0 and 3.0, more preferably between 1.0 and 1.5, and even more preferably between 1.0 and 1.1. Within this range, it can be evaluated that the first discontinuous reinforcing fibers are dispersed randomly in two dimensions within the small piece Ai.

[0095] The plate-shaped composite material 102 of the second embodiment is obtained by stacking the ends of a plurality of small pieces Ai (where i is a natural number) at least in one place, and then heating to melt-bond the plurality of small pieces Ai. Here, stacking at least in one place means, for example, that when 100 small pieces Ai are placed, at least two of them are stacked (overlapping), so that is considered to be at least one overlapping place. Furthermore, stacking may occur when the small pieces Ai are in direct contact with each other, or when a second component, described later, is sandwiched between two small pieces Ai during stacking. In other words, when two small pieces are projected onto the composite material 102 from the thickness direction, the ends of the small pieces Ai should appear to overlap.

[0096] Various methods can be used to melt multiple small pieces of Ai and fuse them together. The manufacturing method for the composite material may be a batch method in which the composite material is obtained by fusion bonding in a mold, or it may be manufactured continuously using a double belt. Continuous manufacturing is preferable from the viewpoint of productivity. The composite material 102 of the second embodiment can also be manufactured in the same manner as the manufacturing examples 1 to 4 of the first embodiment.

[0097] In the plate-shaped composite material 102, small pieces Ai form a post-molten hardened region Di within the plate-shaped composite material where the small pieces Ai harden after melting. It is preferable that the relationship between the number of confounding fibers N1 in the interior (non-laminated region) of the post-molten hardened region Di other than the laminated region 103 and the number of confounding fibers N2 in the laminated region 103 between the post-molten hardened regions Di is N1 > N2. Here, the confounding numbers N1 and N2 can be counted, for example, from cross-sectional images of the same area in the non-laminated region and the laminated region 103 of the post-molten hardened region Di. By satisfying N1 > N2, the amount of springback increases in the non-laminated region where the number of confounding fibers N1 of the post-molten hardened region Di is large, while the springback decreases in the laminated region where the number of confounding fibers N2 of the post-molten hardened region Di is small, thus suppressing springback. A plate-shaped composite material 102 having such a laminated region 103 can have improved moldability compared to a plate-shaped composite material that does not have a laminated region 103 at all.

[0098] When a plate-shaped composite material 102 is heated above its softening point, it can be easily separated between the post-molten hardened regions Di, but it is difficult to tear and separate the post-molten hardened regions Di themselves. When the plate-shaped composite material 102 is heated, the thermoplastic resin contained in the composite material 102 melts, releasing the constraints on the discontinuous reinforcing fibers, and springback 105 occurs, which increases the thickness of the composite material 102 as shown in Figure 9. If the increase in thickness due to springback 105 is large, it becomes difficult to place the plate-shaped composite material 102 with springback 105 between the upper mold 502 and the lower mold 503, as shown in Figure 10, making molding difficult.

[0099] The composite material 102 can be formed into a molded body by hot press molding or cold press molding, similar to the composite material 101 of the first embodiment.

[0100] [Third Embodiment] In addition to the small piece 201 of the first embodiment or the small piece Ai of the second embodiment, a second component containing discontinuous reinforcing fibers and thermoplastic resin may be added to create a plate-shaped composite material. The method of mixing the first component and the second component is not particularly limited. For example, if the small piece 201 made from recycled waste material 301 is used as the first component, virgin material may be used as the second component and mixed with the first component, heated to melt and bond the first and second components together to create a plate-shaped composite material.

[0101] Alternatively, the second component may be applied onto a mobile conveyor while the first component is simultaneously scattered onto the conveyor. Alternatively, the second component may be laminated onto small pieces 201 or small pieces Ai arranged as in the first or second embodiment, and then heated to melt and bond the first and second components to create a plate-shaped composite material. In this case, it is preferable that 0.9 × ty > tz, where ty is the thickness of the small piece that is the first component and tz is the thickness of the layer of the second component.

[0102] The ratio of the first component to the second component is preferably 10:90 to 90:10, more preferably 20:70 to 70:20, and even more preferably 20:70 to 60:40.

[0103] The fiber volume ratio in the first component and the fiber volume ratio in the second component are not particularly limited, but are preferably the same. When the fiber volume ratio in the first component and the fiber volume ratio in the second component are the same, the fiber volume ratio becomes uniform when the first and second components are mixed or laminated. In this case, when the resulting plate-like composite material is used and then crushed to obtain recycled waste material, recycled waste material with a uniform fiber volume ratio can be obtained. This makes recycling management easier. The preferred range for the fiber volume ratio is

[0104] Hereinafter, the discontinuous reinforcing fibers contained in the small piece that is the first component will be referred to as the first discontinuous reinforcing fibers, the thermoplastic resin contained in the small piece that is the first component will be referred to as the first thermoplastic resin, the discontinuous reinforcing fibers contained in the second component will be referred to as the second discontinuous fibers, and the thermoplastic resin contained in the second component will be referred to as the second thermoplastic resin. The first thermoplastic resin and the second thermoplastic resin may be the same type of resin or different types of resin, but it is preferable that they be the same resin.

[0105] The weight-average fiber length Lw1 of the first discontinuous reinforcing fiber is preferably shorter than the weight-average fiber length Lw2 of the second discontinuous reinforcing fiber. That is, it is preferable that Lw2 > Lw1. Specifically, the weight-average fiber length Lw2 of the second discontinuous reinforcing fiber is preferably greater than 5 mm and greater than 10 mm. It is more preferable that the weight-average fiber length Lw2 of the reinforcing fiber is greater than 5 mm and 100 mm or less, more preferably greater than 5 mm and 80 mm or less, and even more preferably greater than 10 mm and 50 mm or less. If the weight-average fiber length Lw2 of the second discontinuous reinforcing fiber is 100 mm or less, the fluidity of the plate-shaped composite material is less likely to decrease when it is manufactured by compression molding, making it easier to create the desired shape. Also, if the weight-average fiber length Lw2 of the second discontinuous reinforcing fiber is greater than 5 mm, the mechanical strength of the resulting molded article is less likely to decrease, which is preferable. Lw1 and Lw2 can be calculated from the above formula (2).

[0106] In addition, in molded articles produced by injection molding, the weight-average fiber length of the discontinuous reinforcing fibers is approximately 0.1 to 0.3 mm. Therefore, in this embodiment, a molded article with a weight-average fiber length of discontinuous reinforcing fibers of 5 mm to 100 mm can be manufactured by compression molding.

[0107] [Evaluation Method] 1. Monofilament ratio The monofilament ratio of the reinforcing fiber bundle of the plate-shaped composite material is measured by taking reinforcing fibers from the composite composition (consisting of a glass fiber aggregate and polypropylene resin) at the manufacturing stage of the small piece 201 (prepared molded body). 200 reinforcing fibers between 3 mm and 100 mm in length are randomly selected using tweezers, and a total of 1200 fibers are extracted from 6 samples. The reason for using a total of 1200 fibers is that, with an error tolerance of ε 3%, a confidence level μ(α) of 95%, and a population ratio ρ of 0.5, the n value derived from the following formula is 1068 fibers. n = N / [(ε / μ(α))² × {(N-1) / ρ(1-ρ)} + 1] n: Required sample size μ(α): 1.96 at 95% confidence N: Population size ε: Error tolerance ρ: Population proportion For all the extracted reinforcing fiber bundles, the weight W of each individual reinforcing fiber is measured using a balance capable of measuring to 1 / 100 mg. At this time, bundles with a width of 0.3 mm or less are defined as single fibers, and bundles with a width exceeding 0.3 mm are defined as fiber bundles. The ratio of single fibers to the total amount of reinforcing fibers is calculated by the following formula: Single fiber ratio = (Weight of single fibers / (Weight of fiber bundles + Weight of single fibers)) × 100

[0108] 2. Preparation for measuring the fiber volume ratio (Vf): A sample is cut from the molded body or the second component, heated to 650°C for 3 hours, and the thermoplastic resin is burned off in the furnace. The mass of the reinforcing fiber and thermoplastic resin is calculated by weighing the sample before and after treatment. Next, the volume ratio Vf of the reinforcing fiber and thermoplastic resin is calculated using the specific gravity of each component. Vf = 100 × volume of reinforcing fiber / (volume of reinforcing fiber + volume of thermoplastic resin)

[0109] 3. Transferability (Moldability) The transferability of the composite materials obtained in each example and comparative example is evaluated. Materials with good transferability are considered to have good moldability. A hemispherical mold with a radius of 150 mm is prepared, and the mold temperature is set to 100°C. The composite material heated to 240°C is placed on the mold and clamped, and after being held at a pressure of 20 MPa for 30 seconds, the molded body is taken. Excellent: The hemispherical shape can be molded without any problems. Good: Transfer defects occur in part of the hemispherical shape. Bad: The plate-like composite material breaks and cannot be molded.

[0110] [Example 1] 1. Preparation of molded body 1 A thermoplastic resin composition was prepared by adding 10 parts by mass of a flame retardant (Adekastab FP2100-JC) to polypropylene resin (Novatec PPBC03C from Nippon Polypropylene Co., Ltd.) as the thermoplastic resin.

[0111] A unidirectional, continuously moving, breathable support with a suction mechanism at its lower end was installed below the thermoplastic resin composition dispenser. While moving the breathable support at 0.5 m / min, the thermoplastic resin composition was sprayed from the dispenser onto the breathable support, fixing the thermoplastic resin composition onto the breathable support.

[0112] A rotary cutter was placed above a breathable support, and the multi-end roving was cut to a constant length of 20 mm using the rotary cutter. At this time, compressed air was supplied directly below the rotary cutter, and the negative pressure generated by the airflow separated the glass fibers from the roll. The compressed air flow rate was 120 L / min.

[0113] Cut glass fibers were scattered onto a pre-made thermoplastic resin composition on a breathable support and fixed to obtain a glass fiber aggregate. The amount of glass fibers supplied was set so that the volume ratio of glass fibers was 40% of the composite material.

[0114] A composite composition of a thermoplastic resin composition and a glass fiber aggregate was prepared in a length of 3 m with a width of 600 mm. The manufacturing speed of the composite composition was 0.5 m / min.

[0115] A composite composition consisting of the prepared glass fiber aggregate and thermoplastic resin composition was heated in a continuous impregnation apparatus to impregnate the glass fibers with polypropylene resin, and then cooled to obtain a ready molding material.

[0116] 1. The prepared molded material was cold-pressed to create a flat, plate-shaped prepared molded body 1. The obtained prepared molded body 1 had a thickness of 1.6 mm and dimensions of 500 mm x 500 mm. 2. Preparation of small pieces 201 The prepared molded body 1 was cut into squares with sides of approximately 100 mm x 100 mm to form small pieces 201. 3. Preparation of plate-shaped composite material Nine small pieces 201 were arranged in 3 columns x 3 rows, with a gap of 20 mm between the ends of the small pieces 201 in the TD direction (X direction) and 40 mm in the MD direction (Y direction). The narrowest clearance of the double belt press was set to 1.0 mm, and the nine small pieces 201 were transported while being heated to 230°C for 2 minutes, and then held at 230°C for 4 minutes to melt and flow the nine small pieces 201, producing a plate-shaped composite material of 340 mm x 380 mm. At this time, the small pieces 201 flowed in a manner that connected the separated regions. The double belt press is equipped with an upper die and a lower die, and the clearance when the distance between the upper die and the lower die is narrowest was defined as the narrowest clearance.

[0117] [Total area of ​​non-flowing region Sa] The total area of ​​the nine small pieces 201 used was defined as the total area of ​​the non-flowing region Sa. [Total area of ​​the composite material] The area of ​​the obtained plate-shaped composite material was defined as Total. [Average pixel value of the entire composite material] The composite material was imaged using X-ray CT, and the obtained image data was processed to divide it into 256 pixel values ​​to calculate the average pixel value P of the entire composite material. [Average pixel value of the non-flowing region] The composite material was imaged using X-ray CT, and the obtained image data was processed to divide it into 256 pixel values ​​to calculate the average pixel value of the region where the small pieces 201 were placed, and this was defined as the average pixel value of the non-flowing region.

[0118] [Flow Distance] The distance between the small pieces 201 in the TD direction (X direction) is defined as the flow distance in the X direction, and the distance between them in the MD direction (Y direction) is defined as the flow distance in the Y direction.

[0119] [Isotropy] A 10 mm wide x 90 mm long specimen is cut from the non-flowing region, and the tensile modulus is measured in an arbitrary direction of the specimen and in a direction perpendicular to it. The ratio (Eδ) obtained by dividing the larger of the two values ​​of the tensile modulus in the arbitrary direction of the specimen and the tensile modulus in the direction perpendicular to that direction by the smaller value is taken as the value of isotropy Iso(a). A 10 mm wide x 90 mm long specimen is cut so as to include the flowing region in the Y direction of the non-flowing region, and the tensile modulus is measured in an arbitrary direction of the specimen and in a direction perpendicular to it. The ratio (Eδ) obtained by dividing the larger of the two values ​​of the two values ​​of the tensile modulus in the arbitrary direction of the specimen and the tensile modulus in the direction perpendicular to that direction by the smaller value is taken as the value of isotropy Iso(b2).

[0120] 4. Preparation of Molded Body Two of the obtained plate-shaped composite materials were stacked, and the plate-shaped composite material, heated above the softening point of the thermoplastic resin, was cold-press molded to obtain a molded body with a thickness of 2 mm. The molded body was placed on a horizontal plane, and the difference between the maximum height from the horizontal plane to the top surface of the composite material and the minimum height was defined as the warp of the molded body. The evaluation of the obtained molded body is shown in Table 1. In addition, the charge rate during molding was set to 90%, which suppressed flow during molding.

[0121] [Comparative Example 1] A 500 mm x 500 mm plate-shaped composite material was prepared in the same manner as in Example 1, except that the thickness of the small pieces 201 (thickness of the prepared molded body 1) was 2.0 mm, and the spacing between the ends of the small pieces 201 was 0 mm in the TD direction and 0 mm in the MD direction. The small pieces 201 flowed outward from the 300 mm x 300 mm placement area of ​​the initially placed small pieces 201 (X direction, Y direction). This was molded to create a molded body. The results are shown in Table 1.

[0122] [Comparative Example 2] A 310 mm x 310 mm plate-shaped composite material was prepared in the same manner as in Example 1, except that the thickness of the small pieces 201 (thickness of the prepared molded body 1) was 1.1 mm, and the ends of the small pieces 201 were spaced apart at a pitch of 5 mm in the TD direction and 5 mm in the MD direction. The small pieces 201 flowed so as to connect the spaced-apart small pieces 201. This was then molded to create a molded body. The results are shown in Table 1.

[0123]

[0124] [Example 2] [Evaluation Method] 1. Mechanical Properties 1.1 Tensile Strength A test specimen was cut from the molded body (a plate-shaped composite material was cold-pressed to form a 2 mm thick plate), and a tensile test was performed using an Instron 5982R4407 universal testing machine, referring to JIS K 7164. The shape of the test specimen was a 1B-type B specimen. The distance between the chucks was 115 mm, and the test speed was 2 mm / min. The evaluation results are described as relative values ​​with Comparative Example 2 set to 100. 1.2 Impact Strength The impact strength was evaluated as follows. A 300 mm x 300 mm section was cut from the molded body (a plate-shaped composite material was cold-pressed to form a 2 mm thick plate), and the four sides were sandwiched in a frame and fixed with bolts so that 200 mm x 200 mm was exposed. A jig is created to drop a 50mm diameter, 3000g weight from 1m above, hitting the center of a fixed composite material. This is repeated 20 times, and the number of times a crack appears on the side opposite to the side that hits the weight is counted to calculate the crack occurrence rate. A smaller number indicates better impact strength.

[0125] 2. Transferability The transferability is evaluated using the molded articles obtained in each example and comparative example. A hemispherical mold with a radius of 150 mm is prepared, and the mold temperature is set to 100°C if the resin is polypropylene resin (PP), and to 150°C if the resin is polyamide 6 resin (PA6). A molded article heated to 240°C if the resin is polypropylene resin (PP), and to 280°C if the resin is polyamide 6 resin (PA6) is placed on the mold and clamped, and after being held at a pressure of 20 MPa for 30 seconds, the molded article is taken off. Excellent: The hemispherical shape can be molded without any problems. Good: Transfer defects occur in part of the hemispherical shape. Bad: The plate-like composite material breaks and cannot be molded.

[0126] 3. Springback: From the 2 mm thick molded body produced in each example and comparative example, cut a 50 mm x 50 mm section, attach a thermocouple to the surface, and place it in an IR heater set to 300°C on both the upper and lower heaters. Heat until the thermocouple temperature reaches 275°C. Remove from the furnace when the thermocouple temperature reaches 275°C, allow to cool and solidify, and measure the wall thickness after preheating. The ratio of the wall thickness before preheating to the wall thickness after preheating is defined as the springback amount and is expressed by the following formula: Springback amount = Wall thickness after preheating (mm) / Wall thickness before preheating (mm)

[0127] 4. Measurement of Fiber Bundle Width 4.1 The monofilament ratio of the reinforcing fiber bundles contained in the prepared molded body or the second component is measured by taking reinforcing fibers from the composite composition (consisting of a glass fiber aggregate and polypropylene resin) during the manufacturing stage of the prepared molded body or the second component. 200 reinforcing fibers between 3 mm and 100 mm in length are randomly selected using tweezers, and a total of 1200 fibers are extracted from 6 samples. The reason for using a total of 1200 fibers is that, with an error tolerance of ε 3%, a confidence level μ(α) of 95%, and a population ratio ρ of 0.5, the n value derived from the following formula is 1068 fibers. n = N / [(ε / μ(α))² × {(N-1) / ρ(1-ρ)} + 1] n: Required sample size μ(α): 1.96 at 95% confidence N: Population size ε: Error tolerance ρ: Population proportion For all the extracted reinforcing fiber bundles, the weight W of each individual reinforcing fiber is measured using a balance capable of measuring to 1 / 100 mg. At this time, bundles with a width of 0.3 mm or less are defined as single fibers, and bundles with a width exceeding 0.3 mm are defined as fiber bundles. The ratio of single fibers to the total amount of reinforcing fibers is calculated by the following formula: Single fiber ratio = (Weight of single fibers / (Weight of fiber bundles + Weight of single fibers)) × 100

[0128] 4.2 Measurement of Bundle Width A 20g sample is prepared from the small piece Ai obtained in each example and comparative example. The sample is heated to 650°C in a nitrogen atmosphere in an electric furnace (FP410 manufactured by Yamato Scientific Co., Ltd.) for 3 hours to burn off organic materials such as matrix resin. A total of 0.5g is randomly taken from the reinforcing fibers contained in the sample after burning using tweezers, and the bundle width of the reinforcing fiber bundles of 0.5mm or more is measured and the average value is calculated.

[0129] 5. Preparation for measuring the fiber volume ratio: A sample is cut from the molded body or the second component, heated to 650°C for 3 hours, and the thermoplastic resin is burned off in the furnace. The mass of the reinforcing fiber and thermoplastic resin is calculated by weighing the sample before and after treatment. Next, the volume ratio Vf of the reinforcing fiber and thermoplastic resin is calculated using the specific gravity of each component. Vf = 100 × volume of reinforcing fiber / (volume of reinforcing fiber + volume of thermoplastic resin)

[0130] 6. Rolling Ratio As mentioned above, the rolling ratio is expressed by the following formula: Rolling Ratio (%) = (1 - ty / tx) × 100

[0131] [Materials] 1. Reinforcement Fibers Two types of reinforcement fibers are prepared: (1) Glass fiber multi-end roving (Owens Corning: OC Paneluxe® 2400Tex) (2) Glass fiber single-end roving (Owens Corning: SE2348 roving 2000Tex) 2. Resin Polypropylene resin: Novatec® PP BC0 3C, manufactured by Nippon Polypropylene Co., Ltd., sometimes referred to as PP. Polyamide 6 resin: (Unitika, A1030, melting point 215-220°C, thermal decomposition temperature 300°C), sometimes referred to as PA6. 3. Flame retardant ADEKA Corporation ADEKA Stab® FP2100-JC

[0132] 1. Preparation of Molded Body 2 As the thermoplastic resin, a mixture of polypropylene resin (Novatec PPBC03C from Nippon Polypropylene Co., Ltd.) and 11 parts by mass of flame retardant (Adeka Stab FP2100-JC) was prepared.

[0133] A unidirectional, continuously moving, breathable support with a suction mechanism at its base was installed below the polypropylene resin dispenser. While moving the breathable support at 2 m / min, the polypropylene resin was sprayed from the dispenser onto the breathable support, fixing the polypropylene resin onto the breathable support to prepare it.

[0134] A rotary cutter was placed above a breathable support, and the glass fiber multi-end roving was cut to a constant length of 20 mm using the rotary cutter. At this time, compressed air was supplied directly below the rotary cutter, and the negative pressure generated by the airflow separated the glass fibers from the roll. The compressed air flow rate was 120 L / min.

[0135] Cut glass fibers were scattered onto a pre-fabricated polypropylene resin on a breathable support and fixed to obtain a glass fiber aggregate. The amount of glass fibers supplied was set so that the volume ratio of glass fibers was 40% of the composite material.

[0136] Using a rotary cutter, a composite composition of polypropylene resin and glass fiber aggregate was prepared with a width of 600 mm and a length of 3 m, using a fixed length of 20 mm. The production speed of the composite composition was 2 m / min.

[0137] The composite composition consisting of the prepared glass fiber aggregate and polypropylene resin was heated in a continuous impregnation apparatus to impregnate the glass fibers with polypropylene resin, and then cooled to obtain a ready molding material.

[0138] The prepared molding material was cold-pressed to create a flat, plate-shaped prepared molded body 2. The resulting prepared molded body 2 had a thickness of 2 mm and dimensions of 500 mm x 500 mm.

[0139] 2. Preparation for creating small pieces Ai The molded body 2 was cut into roughly 100 mm x 100 mm squares to obtain 25 pieces of crushed material. The cut crushed material was rolled using a double belt press at 230°C, with the clearance set so that the small pieces Ai obtained after rolling would have the thickness (1 mm) shown in Table 1, thereby creating small pieces Ai (1 mm thick) of the size shown in Table 2. The shape of the small pieces Ai was approximately elliptical, and the rolling ratio was set to 50%.

[0140] 3. Preparation of plate-shaped composite material The small pieces Ai were arranged with the intersection of their major and minor axes as the center, and the spacing between the centers was 100 mm in the TD direction and 120 mm in the MD direction. The width of the stacking (overlapping width) was set to the "maximum length of the stacked section (mm)" as shown in Table 2. The stacked small pieces Ai were heated in a double belt press with the narrowest clearance set to 1.0 mm, with a heating time of 2 minutes to 230°C and a holding time of 4 minutes to melt and bond multiple small pieces Ai together, and then cooled to obtain a plate-shaped composite material. The double belt press has an upper die and a lower die, and the narrowest clearance was defined as the clearance when the distance between the upper and lower dies was narrowest.

[0141] 4. Preparation of Molded Body Two of the obtained plate-shaped composite materials were stacked, and the plate-shaped composite materials, heated above the softening point of the thermoplastic resin, were cold-press molded to obtain a molded body with a thickness of 2 mm. The evaluation of the obtained molded body is shown in Table 2.

[0142] [Example 3] When creating small pieces Ai, the clearance of the double belt press was set to 0.5 mm to design the thickness of the small pieces Ai to 0.5 mm, and the rolling ratio was set to 75%. The points where the major and minor axes of the small pieces Ai intersect were used as the center, and the distance between the centers was set at a pitch of 150 mm in the TD direction and 220 mm in the MD direction. Except for these, a plate-shaped composite material was created in the same manner as in Example 2. The thickness of the obtained plate-shaped composite material was 0.5 mm, so four of these were stacked to obtain a molded body with a thickness of 2 mm. The results of evaluating the obtained molded body in the same manner as in Example 2 are shown in Table 2.

[0143] Due to the high rolling ratio, the bundles of reinforcing fibers open up, and the bundle width of the reinforcing fibers contained in the small piece Ai becomes larger than in Example 2. As a result, the impact resistance is improved, and the rate of crack occurrence is reduced compared to Example 2.

[0144] [Example 4] Small pieces Ai were prepared using crushed material with a size of 25 mm x 25 mm. The centers of the small pieces Ai were positioned at a pitch of 20 mm in the TD direction and 40 mm in the MD direction, with the intersection of the major and minor axes as the center. The "maximum length of the laminated portion (mm)" of the small pieces Ai is as shown in Table 2. Except for this, a plate-shaped composite material was prepared in the same manner as in Example 2. The evaluation results, in the same manner as in Example 2, are shown in Table 2.

[0145] [Example 5] When creating small pieces Ai, the clearance of the double belt press is set to 0.5 mm to design the thickness of the small pieces Ai to 0.5 mm, and the rolling ratio is set to 75%. The center is the point where the major and minor axes of the small pieces Ai intersect, and the centers are spaced at a pitch of 30 mm in the TD direction and 60 mm in the MD direction. Except for this, a plate-shaped composite material is created in the same manner as in Example 4.

[0146] The resulting plate-like composite material has a thickness of 0.5 mm, so four of these are stacked to obtain a molded body with a thickness of 2 mm. The results of evaluating the obtained molded body in the same manner as in Example 2 are shown in Table 2.

[0147] Due to the high rolling ratio, the bundles of reinforcing fibers open up, and the bundle width of the reinforcing fibers contained in the small piece Ai becomes larger than in Example 4. As a result, the impact resistance is improved, and the rate of crack occurrence is reduced compared to Example 4.

[0148] [Example 6] Single-ended roving is used as the reinforcing fiber. The single-ended roving is passed through a stripping bar to open the fibers by friction and then cut. This increases the single-fiber ratio, and a molded body is created in the same manner as in Example 4, except that a prepared molded body 3 with a single-fiber ratio of 90% for the reinforcing fiber is created. The results of the evaluation, which is the same as in Example 2, are shown in Table 2.

[0149] [Example 7] 1. Preparation of the first component Prepare small pieces of Ai in the same manner as in Example 5. 2. Preparation of the second component and laminate As the thermoplastic resin, prepare a mixture of polypropylene resin (Novatec PPBC03C from Nippon Polypropylene Co., Ltd.) with 11 parts by mass of flame retardant (Adeka Stab FP2100-JC) added.

[0150] A unidirectional, continuously moving, breathable support with a suction mechanism at its base is installed below the polypropylene resin supply machine. Small pieces Ai are placed on the breathable support, centered at the point where the major and minor axes of the small pieces Ai intersect, with a spacing of 30 mm in the TD direction and 60 mm in the MD direction between the centers. The "maximum length of the laminated portion (mm)" of the small pieces Ai is as shown in Table 2.

[0151] While moving a breathable support structure with small pieces of Ai arranged on it at a speed of 2 m / min, polypropylene resin is sprayed onto the breathable support structure from a supply machine, and the polypropylene resin is fixed onto the breathable support structure.

[0152] A rotary cutter is placed above a breathable support, and the glass fiber multi-end roving is cut to a constant length of 20 mm using the rotary cutter. At this time, compressed air is supplied directly below the rotary cutter, and the negative pressure created by the airflow separates the glass fibers from the roll. The compressed air flow rate is set to 120 L / min.

[0153] Cut glass fibers are scattered onto a polypropylene resin that has been pre-fixed on a breathable support, and fixed to obtain a glass fiber aggregate. The supply amount of glass fibers is set so that the volume ratio of glass fibers is 40% of the second component.

[0154] When cutting to a fixed length of 20 mm using a rotary cutter, a composite composition of polypropylene resin and glass fiber aggregate is produced with a width of 600 mm and a length of 3 m. The production speed of the composite composition is 2 m / min.

[0155] After creating the composite composition, small pieces Ai are placed on top of the composite composition, centered at the point where the major and minor axes of the small pieces Ai intersect, with a spacing of 30 mm in the TD direction and 60 mm in the MD direction between the centers. The "maximum length of the laminated portion (mm)" of the small pieces Ai is as shown in Table 2.

[0156] The aggregate / composite composition / laminated aggregate of small Ai pieces created in this way is heated in a continuous impregnation apparatus to melt-bond multiple Ai pieces, and then polypropylene resin is impregnated into the glass fibers and cooled to obtain a plate-shaped composite material. 3. Preparation of molded body The prepared plate-shaped composite material is cold-pressed to create a molded body. The evaluation is shown in Table 2.

[0157] [Example 8] 1. Preparation of the first component The first component is prepared in the same manner as in Example 4. 2. Preparation of the second component and mixing of the first component As a thermoplastic resin, a mixture is prepared by adding 11 parts by mass of a flame retardant (Adeka Stab FP2100-JC) to polypropylene resin (Novatec PPBC03C from Nippon Polypropylene Co., Ltd.).

[0158] A unidirectional, continuously moving, breathable support with a suction mechanism at its bottom is installed below the polypropylene resin dispenser. While moving the breathable support at 2 m / min, the polypropylene resin is sprayed from the dispenser onto the breathable support, fixing the polypropylene resin onto the breathable support to prepare the polypropylene resin.

[0159] A rotary cutter is placed above a breathable support, and the glass fiber multi-end roving is cut to a constant length of 20 mm using the rotary cutter. At this time, compressed air is supplied directly below the rotary cutter, and the negative pressure created by the airflow separates the glass fibers from the roll. The compressed air flow rate is 120 L / min.

[0160] Cut glass fibers are scattered onto a pre-fabricated polypropylene resin on a breathable support and fixed to obtain a glass fiber aggregate. The amount of glass fibers supplied is set so that the volume ratio of glass fibers is 40% of the second component.

[0161] When cutting to a fixed length of 20 mm using a rotary cutter, a composite composition of polypropylene resin and glass fiber aggregate is produced with a width of 600 mm and a length of 3 m. The production speed of the composite composition is 2 m / min.

[0162] Simultaneously with scattering the glass fibers, 1200 small Ai fragments are randomly scattered over an area with an MD of 600 mm and a TD of 3 m. Visual inspection confirms that the Ai fragments are stacked on top of each other. This creates a mixture in which the first and second components are mixed together. The weight ratio of the first component (Ai fragments) to the second component (composite composition) in the mixture is 50:50.

[0163] The composite composition (second component) consisting of the prepared glass fiber aggregate and polypropylene resin, and the first component (small pieces Ai) are heated in a continuous impregnation apparatus to melt-bond multiple small pieces Ai, impregnate the glass fibers with polypropylene resin, and cool to obtain a 2 mm thick plate-shaped composite material by mixing the first and second components. 3. Preparation of molded body Subsequently, a 2 mm thick molded body is created by cold press molding. The evaluation is shown in Table 2.

[0164] [Example 9] A plate-shaped composite material is prepared in the same manner as in Example 3, except that the resin is polyamide 6 (PA6) to create the prepared molded body 4. When rolling using a double belt press, the temperature is set to 280°C. The material is heated to 280°C for 2 minutes, held at 280°C for 6 minutes, and then cooled to obtain a plate-shaped composite material. The evaluation of the molded body is shown in Table 1.

[0165] [Comparative Example 3] Small pieces of Ai obtained in Example 1 are cut out to prepare 100 mm x 100 mm square pieces of Ai. A molded body is obtained in the same manner as in Example 2, except that these are laid out without gaps and without overlapping.

[0166] [Comparative Example 4] In Example 7, a plate-shaped composite material is created using only the second component, without using the first component. Two of these plates are laminated to create a molded body. The evaluation is shown in Table 2.

[0167]

[0168] The structure and method for manufacturing the structure described herein are applicable to various components of mobile bodies and industrial machinery, and can be applied to, for example, battery boxes, battery bottom protectors, and the like.

Claims

1. A method for manufacturing a plate-shaped composite material by arranging a plurality of small pieces containing discontinuous reinforcing fibers and thermoplastic resin, heating and fusing them together, wherein the manufactured plate-shaped composite material has a non-flow region which is the area where the small pieces were arranged before heating and melting, and a flow region which is the area other than the non-flow region, and the relationship between the total area Sa of the non-flow regions and the total area Stotal of the plate-shaped composite material satisfies 0.4 × Stotal < Sa < 0.8 × Stotal.

2. The method for manufacturing a composite material according to claim 1, wherein the average pixel value of the non-flowing region measured in the following steps is less than or equal to 0.95 × the average pixel value P of the entire composite material. Step 1. Process the image data obtained from X-ray CT of the composite material to divide it into 256 pixel values, and calculate the average pixel value P of the entire composite material. Step 2. Divide the composite material into 1 mm x 1 mm sections. Step 3. In the image data, the pixel values ​​of each section are measured and averaged over 100 points to obtain the average pixel value of the non-flowing region.

3. A method for manufacturing a composite material according to claim 1 or 2, wherein the average thickness of the small pieces is Ty, and the average thickness of the composite material is 0.9 × Ty or less.

4. A method for manufacturing a composite material according to any one of claims 1 to 3, wherein the small pieces are in the shape of a flat plate.

5. The method for producing a composite material according to any one of claims 1 to 4, wherein the small pieces are recycled waste materials obtained by crushing a molded body containing discontinuous reinforcing fibers and a thermoplastic resin.

6. A method for manufacturing a composite material according to any one of claims 1 to 5, comprising the step of transporting the plurality of small pieces in an arranged state, heating them to fuse them together, and manufacturing a plate-shaped composite material, wherein the plate-shaped composite material is an XY plane, the Y direction is the MD direction which is the direction in which the small pieces are transported, and the X direction is the TD direction which is perpendicular to the MD direction, and the flow distance when the small pieces are heated, melted, and flowed is such that the flow distance in the X direction is less than the flow distance in the Y direction.

7. A method for manufacturing a plate-shaped composite material according to any one of claims 1 to 6, comprising the steps of transporting the plurality of small pieces in an arranged state, heating them to fuse them together, and manufacturing a plate-shaped composite material, wherein when the plate-shaped composite material is an XY plane, the Y direction is the MD direction which is the direction in which the small pieces are transported, and the X direction is the TD direction which is perpendicular to the MD direction, the relationship between the isotropy Iso(a) of the non-flowing region and the isotropy Iso(b2) of the flowing region in the Y direction of the non-flowing region satisfies Iso(a) < Iso(b2).

8. A method for manufacturing a molded article using a plate-shaped composite material obtained by the manufacturing method described in any one of claims 1 to 7, wherein the plate-shaped composite material is arranged such that the charge rate represented by the following formula (3) is 50% or more. Charge rate (%) = 100 × Projection area of ​​the plate-shaped composite material (mm²) ２ ) / mold cavity area (mm²) ２ ) (3) 9. A method for producing a plate-shaped composite material by arranging a plurality of small pieces containing discontinuous reinforcing fibers and a thermoplastic resin, heating and fusing them together, wherein the weight-average fiber length Lw1 of the discontinuous reinforcing fibers is 5 mm or more, the discontinuous reinforcing fibers are randomly dispersed in the in-plane direction of the small pieces, and when the plurality of small pieces are arranged, the ends of the plurality of small pieces are stacked together at least in one place.

10. The method for manufacturing a plate-shaped composite material according to claim 9, wherein the ratio obtained by dividing the larger of the tensile modulus values ​​measured by tensile testing the plate-shaped composite material in two mutually orthogonal directions by the smaller value is 1.0 or more and 3.0 or less.

11. A method for manufacturing a plate-shaped composite material, comprising: a first component comprising a plurality of small pieces in which the first discontinuous reinforcing fibers are randomly dispersed in the in-plane direction, and a first discontinuous reinforcing fiber having a weight-average fiber length Lw1 of 5 mm or more; and a second component comprising a second discontinuous fiber having a weight-average fiber length Lw2 longer than Lw1, and a second thermoplastic resin; and a method for manufacturing a plate-shaped composite material by heating to melt-bond the first component and the second component.

12. A method for manufacturing a plate-shaped composite material, comprising laminating a first component consisting of a plurality of small pieces in which the first discontinuous reinforcing fibers are randomly dispersed in the in-plane direction, the first component comprising a first discontinuous reinforcing fiber having a weight-average fiber length Lw1 of 5 mm or more and a first thermoplastic resin, and a second component comprising a second discontinuous fiber having a weight-average fiber length Lw2 longer than Lw1 and a second thermoplastic resin, and heating to melt-bond the first component and the second component to produce a plate-shaped composite material.

13. The method for manufacturing a plate-shaped composite material according to claim 9 or 10, wherein the small pieces form post-molten hardened regions in a plate-shaped composite material, N1 is the number of intertwined discontinuous fibers in non-laminated regions where the post-molten hardened regions are not laminated with each other, and N2 is the number of intertwined discontinuous fibers in laminated regions where the post-molten hardened regions are laminated with each other, such that N1 > N2.

14. A method for manufacturing a plate-shaped composite material according to any one of claims 9 to 13, comprising crushing a used molded body to obtain crushed material having a plate thickness tx, melting the crushed material and compressing it in the plate thickness direction to produce small pieces having a thickness ty smaller than tx.

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