JP2013193243A - Method of manufacturing fiber reinforced resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing fiber reinforced resin molding capable of performing press forming with high fluidity by using a stampable base material with reinforced fibers favorably dispersed.SOLUTION: In a method of manufacturing fiber reinforced resin molding, when press forming the fiber reinforced resin material that a plurality of reinforced fiber mats are laminated and impregnated with a thermoplastic resin in a cavity formed between mutually facing molds, while sticking a leading end side part of an inner layer of the fiber reinforced resin material extruded toward a lateral side of the cavity to an inner face of the cavity when press forming, a succeeding part of the inner layer is fluidized to charge the fiber reinforced resin material into the cavity.

Description

  The present invention relates to a method for producing a fiber reinforced resin molded body, and more particularly to a method for producing a fiber reinforced resin molded body by press molding using a stampable base material containing reinforcing fibers.

  A method for producing a fiber-reinforced resin molded body by heating and press-molding using a stampable base material made of a thermoplastic resin containing reinforcing fibers is known (for example, Patent Documents 1 and 2). In such a conventional technique, as a stampable base material capable of expressing good fluidity during press molding, for example, from a glass fiber reinforced thermoplastic resin formed into a plate shape (sheet shape) by dispersing chopped glass fibers. Stampable seats that are used are used.

  However, in the production of a fiber reinforced resin molded article by press molding using a stampable base material having good fluidity as described above, the strength and rigidity of the molded article are manifested due to poor dispersion of the reinforcing fibers during press molding. There is a problem that the rate is low.

  On the other hand, a stampable base material in which reinforcing fibers are well dispersed by a papermaking method is also known. However, when this type of conventional stampable base material is used, the strength and rigidity of the molded body can be expressed, but at the time of press molding Since the fluidity is low, it may be difficult to mold the molded body of the desired form by flowing the base material to the desired form, and it is difficult to improve the productivity due to the low fluidity. is there.

JP-A-6-320538 JP 2007-313726 A

  In view of the above-described prior art, it is therefore an object of the present invention to use a stampable base material in which reinforcing fibers are well dispersed, and to perform press molding with high fluidity. Is to provide a method for producing a fiber-reinforced resin molded product that can be produced with high productivity.

  In order to solve the above-described problems, a method for producing a fiber-reinforced resin molded body according to the present invention includes forming a fiber-reinforced resin material in which a plurality of reinforcing fiber mats are laminated and impregnated with a thermoplastic resin between molds facing each other. When the fiber-reinforced resin molded body is manufactured by press molding in the cavity, the tip side portion of the inner layer of the fiber-reinforced resin material extruded toward the side of the cavity at the time of press molding is formed on the inner surface of the cavity. The fiber reinforced resin material is filled in the cavity by causing the subsequent portion of the inner layer to flow while being attached to the cavity.

  That is, the fiber reinforced resin material (that is, the fiber reinforced resin material corresponding to the conventional stampable base material) used for press molding in the present invention is impregnated with a thermoplastic resin in a laminate of a plurality of relatively thin reinforcing fiber mats. The fiber reinforced resin material is press-molded in a cavity formed between molds facing each other. At the time of press molding, the fiber reinforced resin material arranged in the cavity is flowed so as to be pushed out to the side of the cavity, but at this time, the fiber reinforced resin material has its inner layer side portion changed to the outer layer side portion. Compared to the side of the cavity, it tends to be pushed out larger (farther). And while the front end side portion of the inner layer of the fiber reinforced resin material to be extruded is stuck to the inner surface of the cavity, the subsequent portion of the inner layer flows, that is, the front end side portion of the inner layer stuck to the inner surface of the cavity The fiber reinforced resin material is sequentially filled into the cavity so that the subsequent portion of the inner layer flows along the path that returns from the U-turn. In this application, a fluid state in which the leading portion of the inner layer of the fiber reinforced resin material extruded is adhered to the inner surface of the cavity and the subsequent portion of the inner layer flows is referred to as “bear flow”. By realizing such a bare flow, a fiber reinforced resin material made of a laminate of a plurality of relatively thin reinforcing fiber mats impregnated with a thermoplastic resin has a relatively thin layered state in which each layered portion has a tip. In the cavity, it is gradually and smoothly filled toward the side of the cavity so as to be folded in a U shape toward the part. Therefore, excellent fluidity into a predetermined region in the cavity is realized. Then, by forming a fiber-reinforced resin material using a laminate of relatively thin reinforcing fiber mats in which reinforcing fibers are well dispersed, the above-described excellent fluidity is achieved, and the reinforcing fibers in the molded body It is also possible to realize a good dispersion state. High strength and rigidity of the molded body are ensured by good dispersion of the reinforcing fibers, and a molded body of a desired form can be manufactured with high productivity by excellent fluidity.

  In the method for producing a fiber-reinforced resin molded body according to the present invention, the bare flow basically occurs for each reinforcing fiber mat layer constituting the fiber-reinforced resin material. In order to realize the excellent fluidity as described above, the inner layer of the fiber reinforced resin material is flowed so that each layered portion is folded in a U shape toward the tip in a relatively thin layered state. For that purpose, it is preferable to laminate each reinforcing fiber mat layer of the fiber reinforced resin material with a thickness of 0.5 mm or less. When the reinforcing fiber mat layer is too thick, it becomes difficult to obtain a U-shaped folded flow state.

Moreover, in this invention, it is preferable that the bending rigidity (EI) of the reinforced fiber of the said fiber reinforced resin material is 2.8E-7N * cm < ² > or less. If the bending rigidity (EI) is higher than this, the rigidity of each layered portion in the U-shaped folded flow of each layered portion as described above increases, so that the U-shaped folded flow hardly occurs, and the target bear flow Is difficult to obtain. However, if the flexural rigidity (EI) of the reinforcing fiber is too low, the rigidity of the molded body after molding may be lowered. Therefore, in view of the design target of the rigidity of the molded body, the bending rigidity is appropriately within the above range. It is desirable to select. The fiber diameter of the reinforcing fiber may be selected so as to satisfy such an appropriate bending rigidity range.

  Moreover, in this invention, it is preferable that the die temperature at the time of press molding is lower than melting | fusing point of the said thermoplastic resin, More specifically, it is preferable that it is more than the glass transition temperature of the said thermoplastic resin and lower than melting | fusing point. By setting the mold temperature in this way, it is possible to maintain a desired state of the thermoplastic resin and realize a desirable flow state of the fiber reinforced resin material.

  Moreover, in this invention, it is preferable that the average fiber length of the reinforced fiber of the said fiber reinforced resin material exists in the range of 10-50 mm. If the average fiber length is longer than this range, it is possible to obtain high strength and rigidity of the molded body, but the fluidity during press molding may be deteriorated. There is a risk that strength and rigidity are lowered.

  Further, in the present invention, the type of the reinforcing fiber of the fiber reinforced resin material is not particularly limited, but considering that the basic goal is to increase the strength and rigidity of the molded body due to the presence of the reinforcing fiber, For example, it is preferable to include at least one of carbon fiber, glass fiber, and aramid fiber.

  Moreover, in this invention, it does not specifically limit as an average diameter of the reinforced fiber of the said fiber reinforced resin material, What is necessary is just to select suitably from the range of 1-50 micrometers so that preferable bending rigidity can be achieved as mentioned above.

  In the present invention, the method for forming the plurality of reinforcing fiber mats constituting the fiber reinforced resin material is not particularly limited, but the following method is preferable. For example, at least a reinforcing fiber mat laminated as an inner layer of the fiber reinforced resin material is preferably manufactured by a carding method. When the carding method is used, the main orientation direction of the reinforcing fiber can be controlled in a specific direction (in other words, the orientation direction of the reinforcing fiber can be intentionally made anisotropic. For example, it is possible to orient the reinforcing fibers in the direction along the above-mentioned U-shaped folded flow (in this case, the reinforcing fibers are set with a low rigidity as described above, and thus the reinforcing fibers). It is preferable that the rigidity of the reinforcing fiber does not interfere with the U-shaped folded flow), and is oriented in a direction perpendicular to the direction along the U-shaped folded flow. It is also possible to prevent from substantially affecting. A specific method of carding will be exemplified in an example described later.

  In this case, the degree of orientation of the reinforcing fiber mat produced by the carding method is preferably 1.5 or more. A method for measuring the degree of orientation will be described later. By carrying out carding so that the average value of the orientation degree of the reinforcing fiber mat is 1.5 or more, the reinforcing fibers can be intentionally oriented with a desired anisotropy. It is possible to set in accordance with the fluidity aiming at specific orientation and the strength and rigidity of the molded body.

  Moreover, in this invention, it is also preferable to laminate | stack at least 2 layers of the reinforced fiber mat of the said fiber reinforced resin material at 0/90 degree, for example. This is because the reinforcing fiber is oriented in the direction in which the reinforcing fiber is not substantially resistant to the reinforcing fiber mat layer in which the reinforcing fiber is oriented in the direction in which the rigidity of the reinforcing fiber is resistant to the U-shaped folded flow. It is a form in which both a mat layer and a target U-shaped folding flow are easily generated and strength and rigidity anisotropy in the final molded body are eliminated as much as possible.

  In the present invention, for example, the reinforcing fiber mat laminated as the outermost layer of the fiber reinforced resin material can be manufactured by a papermaking method. In the papermaking method, unlike carding, the reinforcing fibers are arranged in a substantially random direction. The outermost layer of the fiber reinforced resin material is a layer that does not need to contribute to the aforementioned U-shaped folded flow, and is a layer that is highly likely to remain as the outermost layer of the molded body even after press molding. By producing the reinforcing fiber mat laminated as the outermost layer by the papermaking method, it is possible to improve the appearance of the surface of the molded body without impairing the excellent fluidity during press molding.

  Thus, according to the method for producing a fiber-reinforced resin molded body according to the present invention, a fiber-reinforced resin material in which reinforcing fibers are well dispersed can be press-molded with excellent fluidity, and thereby a desired form. The fiber-reinforced resin molded product can be produced with high productivity. In addition, high strength and rigidity of the molded product can be secured by good dispersion of the reinforcing fibers, and fiber reinforced resin molded products can be molded with high precision by excellent fluidity, and burr-free molding is also possible. The manufacturing cost can be reduced in combination with facilitation of molding due to the property.

It is the schematic diagram corresponding to the Example of this invention which shows an example of the flow state of the fiber reinforced resin material at the time of press molding in the manufacturing method of the fiber reinforced resin molding which concerns on one embodiment of this invention. It is the schematic diagram corresponding to the comparative examples 1, 2, and 4 of this invention which shows an example of the flow state of the fiber reinforced resin material at the time of press molding in the manufacturing method of the conventional fiber reinforced resin molded object. It is a schematic diagram corresponding to the comparative example 3 of this invention which shows an example of the flow state of the fiber reinforced resin material at the time of press molding in the manufacturing method of another conventional fiber reinforced resin molded object. It is a schematic diagram which shows an example of the apparatus used for the carding process in this invention. It is a schematic perspective view of the sample for orientation degree measurement. FIG. 4 is a schematic perspective view of a block-shaped minute region obtained by dividing a measurement sample from three-dimensional image data obtained by X-ray CT, and a schematic diagram when coordinate axes are set thereto. It is a schematic diagram which shows the state which pulled the scanning line of the angle (phi) from one axis | shaft in parallel with respect to the set coordinate axis. It is a schematic diagram which shows a mode that the average crossing length of the part where the carbon fiber in a micro area | region and a scanning line cross | intersect is calculated | required. FIG. 6 is a graph plotting average cross length as a function of scan line angle. FIG. It is a schematic diagram which shows a mode that several average crossing length is plotted as a function of the angle of a scanning line. FIG. 6 is a schematic diagram showing how to obtain a major axis a, a minor axis b, and a major axis angle φ ₀ in a graph in which the average crossing length is plotted as a function of the scanning line angle φ. It is the graph which plotted the average transverse length by the function of the angle (phi) of a scanning line in the case where the carbon fiber is orientated at random, and when it is completely oriented in one direction. It is a schematic diagram which shows a mode that a micro area | region is moved with respect to the whole X-ray CT image. It is a graph which shows an example which measured and calculated the average value of the degree of orientation. It is the schematic block diagram (A) which shows the mode of press molding using the CFRP sheet produced in the Example of this invention, and the schematic plan view (B) which shows the dimension of the CFRP sheet and mold cavity at that time.

Embodiments of the present invention will be described below with reference to the drawings.
In the method for producing a fiber-reinforced resin molded body according to the present invention, a fiber-reinforced resin material in which a plurality of reinforcing fiber mats are laminated and impregnated with a thermoplastic resin is press-molded in a cavity formed between molds facing each other. Thus, when manufacturing a fiber reinforced resin molded body, the tip side portion of the inner layer of the fiber reinforced resin material extruded toward the side of the cavity at the time of press molding is stuck to the inner surface of the cavity, and the subsequent of the inner layer The portion is made to flow, that is, made to flow by bare flow, and the fiber-reinforced resin material is filled into the cavity.

  For example, as schematically shown in FIG. 1, fiber reinforced fibers in which a plurality of reinforcing fiber mats 1 (shown as an integrated layer with impregnated resin in FIG. 1) are laminated and impregnated with a thermoplastic resin. The resin material 2 is press-molded in a cavity 5 formed between molds facing each other (between molds 3 and 4). At the time of the press molding, the tip side portion of the inner layer 2a of the fiber reinforced resin material extruded toward the side of the cavity 5 (for example, toward the right side in FIG. 1) is sequentially stuck to the inner surface 5a of the cavity 5. A subsequent portion of the inner layer 2a flows toward the side of the cavity 5, and a bare flow state appears. As the press of the mold 3 indicated by the arrow P progresses, such a bare flow advances, and the fiber reinforced resin material 2 is filled in the cavity 5 accordingly.

  Such a bare flow, that is, the tip side portion of the inner layer 2a of the fiber reinforced resin material 2 to be extruded is stuck to the inner surface 5a of the cavity 5, and the subsequent portion of the inner layer 5a is stuck to the inner surface 5a of the cavity 5. Each inner layer 2a is filled in the cavity 5 toward the side of the cavity 5 by realizing a flow state in which the fluid flows along a path returning from the leading end portion of the inner layer 2a. It will be done. Since each inner layer 2a is made of a relatively thin fiber reinforced resin material layer using a relatively thin reinforcing fiber mat 1, a U-shaped flow path can be easily realized, and each inner layer 2a can be smoothly and smoothly passed through a bare flow. A predetermined press molding region in the cavity 5 is filled. Therefore, the excellent fluidity | liquidity as the fiber reinforced resin material 2 whole press-molded is implement | achieved.

  FIG. 2 shows an example of the flow state by the layered flow of the fiber reinforced resin material during press molding in the conventional method for producing a fiber reinforced resin molded body shown for comparison, and Comparative Examples 1 and 2 of the present invention. 4 corresponds to the flow state. That is, the fiber reinforced resin material 8 that is press-molded between the molds 6 and 7 is such that each inner layer 8a is sequentially pushed out in layers toward the side of the cavity 9 in the cavity 9, and is filled in the cavity 9. Go.

  FIG. 3 shows an example of a flow state by fountain flow of a fiber reinforced resin material at the time of press molding in another conventional method for producing a fiber reinforced resin molded body shown for comparison, and Comparative Example 3 of the present invention. It corresponds to the flow state in. That is, the fiber reinforced resin material 12 press-molded between the molds 10 and 11 is extruded so that the central portion in the thickness direction protrudes in the cavity 13 toward the side of the cavity 13, and fills the cavity 13. It will be done.

  In order to reliably realize the bare flow state in the present invention as shown in FIG. 1, each of the plurality of reinforcing fiber mats constituting the fiber reinforced resin material, in particular, the reinforcing fiber mat corresponding to the inner layer 2 a is compared. A thin mat layer (for example, a mat layer having a thickness of 0.5 mm or less) and, desirably, an optimum degree of orientation (for example, 1.5 or more depending on the fiber-reinforced resin molded body to be molded) It is preferable to form a mat layer having a degree of orientation. For that purpose, for example, at least a reinforcing fiber mat laminated as an inner layer of the fiber reinforced resin material is preferably manufactured by a carding method. In addition, when the carding method is used, the main orientation direction of the reinforcing fiber can be controlled to a specific direction (in other words, the orientation direction of the reinforcing fiber is intentionally made anisotropic. Therefore, it is possible to form a mat layer having an optimum degree of orientation according to the fiber-reinforced resin molded body to be molded.

  The case where a reinforcing fiber mat is formed as a sheet-like substrate made of carbon fibers will be described below with respect to a carding method suitable for the present invention. Carding as used in the present invention refers to, for example, applying a force in approximately the same direction with an aggregate of discontinuous carbon fibers in a comb shape or the like, or aligning the directions of discontinuous carbon fibers, An operation to align the direction and open the carbon fiber. Generally, it is carried out using a carding apparatus having a roll having a large number of needle-like projections on the surface and / or a roll around which a metallic wire having a saw-like projection of a saw is wound. A specific example of the entire carding apparatus will be described later. In carrying out such carding, it is preferable to shorten the time (residence time) in which the carbon fiber is present in the carding apparatus in order to prevent the carbon fiber from being broken. Specifically, it is preferable to transfer the carbon fiber present on the wire wound around the cylinder roll of the carding apparatus to the downstream doffer roll in the shortest possible time. Therefore, in order to promote such a transition, the rotation speed of the cylinder roll is preferably rotated at a high rotation speed such as 300 rpm or more. For the same reason, the surface speed of the doffer roll is preferably a high speed such as 10 m / min or more. Similarly, in order to reduce the damage to the carbon fiber and prevent the carbon fiber from being pressed and sinking on the surface of a cylinder roll, a worker roll, a stripper roll (refer to a specific configuration example described later), each roll It is important to make the clearance between them relatively wide as compared with the case of carding ordinary organic fibers. For example, the clearance between the cylinder roll, worker roll, and stripper roll is preferably 0.5 mm or more, more preferably 0.7 mm or more, and further preferably 0.9 mm or more. .

  FIG. 4 shows an example of the carding device. The carding device 21 includes a cylinder roll 22, a take-in roll 23 provided on the upstream side near the outer peripheral surface, and a take-in roll 23. A doffer roll 24 provided close to the outer peripheral surface of the cylinder roll 22 on the opposite downstream side, and provided close to the outer peripheral surface of the cylinder roll 22 between the take-in roll 23 and the doffer roll 24. A plurality of worker rolls 25, a stripper roll 26 provided close to the worker roll 25, a feed roll 27 and a belt conveyor 28 provided close to the take-in roll 23 are mainly configured.

  For example, an aggregate of discontinuous carbon fibers 29 is supplied onto the belt conveyor 28, and the discontinuous carbon fibers 29 pass through the outer peripheral surface of the feed roll 27 and then the outer peripheral surface of the take-in roll 23. Introduced on the surface. Until this stage, the discontinuous carbon fibers 29 are in a cotton-like form. A part of the cotton-like carbon fiber introduced on the outer peripheral surface of the cylinder roll 22 is wound around the outer peripheral surface of each worker roll 25, but this carbon fiber is peeled off by each stripper roll 26 and again the cylinder roll 22. It is returned to the outer peripheral surface of. A large number of needles and protrusions are present on the outer peripheral surface of each of the feed roll 27, take-in roll 23, cylinder roll 22, worker roll 25, and stripper roll 26. Are opened into a single fiber shape by the action of the needle, and at the same time, the orientation direction of most of the carbon fibers is aligned with a specific direction, that is, the rotation direction of the cylinder roll 22. The carbon fiber that has been opened through such a process and whose fiber orientation has been advanced moves onto the outer peripheral surface of the doffer roll 24 as a sheet-like web 30 that is one form of the carbon fiber aggregate. Further, by pulling the web 30 while narrowing the width to a predetermined width, a reinforcing fiber mat of a sheet-like substrate made of discontinuous carbon fibers (reinforcing fibers) referred to in the present invention is formed.

  In the carding as described above, the aggregate of the discontinuous carbon fibers 29 may be composed of only carbon fibers, but the discontinuous organic fibers, particularly thermoplastic resin fibers, are mixed to perform carding. It can also be done. In particular, it is preferable to add thermoplastic resin fibers when carding, because the carbon fibers can be prevented from breaking during carding. Since carbon fiber is rigid and brittle, it is difficult to be entangled and easily broken. Therefore, in the carbon fiber aggregate which consists only of carbon fiber, there exists a problem that a carbon fiber is easy to cut during carding, or a carbon fiber tends to drop out. Therefore, by including thermoplastic resin fibers that are flexible, difficult to break, and easily entangled, it is possible to form a carbon fiber aggregate in which the carbon fibers are hardly cut and the carbon fibers are not easily dropped. It is also preferable to perform carding by mixing such organic fibers, particularly thermoplastic resin fibers, and after the carding, at least a part of the organic fibers is melted and then pressed. That is, an organic fiber in a moderately small amount is mixed, and at least the organic fiber is oriented in a state in which the carbon fiber is oriented with anisotropy intentionally so that the average value of the orientation degree is within a predetermined range. By melting a part of the organic fiber, the organic fiber can serve as a binder for maintaining the form of the sheet-like substrate having a predetermined degree of orientation. It is also preferable to fix it moderately through fibers.

  When the thermoplastic resin fibers are included in the carbon fiber aggregate as described above, the carbon fiber content in the carbon fiber aggregate is preferably 50 to 95 mass%, more preferably 70 to 95 mass%. is there. If the proportion of carbon fiber is low, it will be difficult to obtain high mechanical properties when carbon fiber reinforced plastic is used, and conversely if the proportion of thermoplastic resin fiber is too low, the above-mentioned carbon fiber aggregate will contain thermoplastic resin fibers. The role of the thermoplastic resin fiber when mixing is not expected or becomes smaller.

  Moreover, in order to further enhance the entanglement effect by the above-described thermoplastic resin fibers, it is preferable to crimp the thermoplastic resin fibers. The degree of crimping is not particularly limited, but generally, thermoplastic resin fibers having a number of crimps of about 5 to 25 crests / 25 mm and a crimping rate of about 3 to 30% can be used.

  There is no restriction | limiting in particular as a material of this thermoplastic resin fiber, It can select suitably in the range which does not reduce the mechanical characteristic of a carbon fiber reinforced plastic largely. For example, polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon 6, nylon 6,6, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyether ketone, polyether sulfone, aromatic polyamide, etc. A fiber obtained by spinning a resin of the above can be used. The material of the thermoplastic resin fiber is preferably selected as appropriate in combination with a matrix resin of carbon fiber reinforced plastic. In particular, a thermoplastic resin fiber using the same resin as the matrix resin, a resin compatible with the matrix resin, or a resin having high adhesiveness with the matrix resin is preferable because it does not deteriorate the mechanical properties of the carbon fiber reinforced plastic.

Next, the method for measuring the orientation degree of the reinforcing fibers in the present invention will be described taking the case of carbon fibers as an example.
1. Equipment used:
X-ray CT: TDM1000-IS manufactured by Yamato Science Co., Ltd.

2. Software for calculating orientation:
TRI-3D VOL R8.0 manufactured by Ratoku System Engineering Co., Ltd.

3. A measurement sample 41 having a size of 5 × 9 × 0.35 mm as shown in FIG. 5 is taken out from the sheet-like base material composed of discontinuous carbon fibers after carding in the present invention, and is placed on the base 42. The orientation degree was measured and calculated for a range of 2.55 × 2.55 × 0.35 mm. Note that the orientation direction of the sample 41 in FIG. 5 coincides with the carding direction.

4). Measurement and Calculation of Orientation Degree (1) As shown in FIG. 6, the three-dimensional image data 43 obtained by photographing the above sample with X-ray CT is divided into minute block-shaped regions 44. However, the size of the minute region may be appropriately adjusted in consideration of the size of the carbon fiber.

(2) As shown in FIG. 6, one minute area 44 is extracted from the three-dimensional image data 43, and a coordinate axis is set. Here, in order to make it easy to understand, the description will be made in two dimensions of the X and Y axes.

(3) Next, as shown in FIG. 7, with respect to the set coordinate axis, a scanning line 45 of an angle φ is drawn in parallel from one axis. The pitch of the scanning lines may be adjusted as appropriate in consideration of the size of the carbon fiber.

(4) Next, as shown in FIG. 8, the average length (= average crossing length L1) of the portion where the carbon fiber 46 in the minute region 44 and the scanning line 45 intersect is obtained. Since there are actually a plurality of fibers, the average length of the portion that intersects the scanning line 15 is obtained.

(5) Next, as shown in FIG. 9, the average transverse length L1 is plotted on another graph as a function of the angle φ of the scanning line 15 (in FIG. 9, plotted for an angle φ1 of the scanning line 45). Have been).

(6) Next, as shown in FIG. 10, the angle φ of the scanning line 45 is changed, and the above operations (4) and (5) are repeated. Plot as a function of angle φ. In FIG. 10, the figure plotted about average crossing length L1 and average crossing length L2 is shown.

(7) Next, as shown in FIG. 11, in the graph in which the average transverse length is plotted as a function of the scanning line angle φ, the major axis a, minor axis b, and major axis angle φ ₀ are obtained. The major axis angle φ ₀ is defined as the main orientation direction, and the ratio a / b between the major axis and the minor axis is defined as the degree of orientation in the present invention. In the present invention, it is preferable to control the average value of the degree of orientation within a predetermined range. Incidentally, when the carbon fibers are completely randomly oriented, the graph shown in FIG. 11 becomes a perfect circle as shown in FIG. 12A (random orientation: a / b = 1). On the other hand, when the carbon fibers are perfectly oriented in one direction, the graph shown in FIG. 11 is a straight line as shown in FIG. 12B (complete orientation: a / b = ∞).

(8) Next, as shown in FIG. 13, the micro region 44 is moved, and the operations (2) to (7) are repeated for the entire X-ray CT image 43. When moving, it may be preferable to overlap the area before the movement.

  FIG. 14 illustrates an example (within a preferred range in the present invention) in which the orientation angle and the average value of the orientation degree in the present invention are measured and calculated by the above method.

Example 1
Carbon fiber (abbreviated as “” in Table 1, “T700S”, manufactured by Toray Industries, Ltd., density 1.8 g / cm ³ , diameter 7 μm, number of filaments 12,000) is cut into 20 mm and then put into a cotton opening machine As a result, an opened carbon fiber was obtained. The opened carbon fiber was again put into a cotton opening machine to obtain a cotton-like carbon fiber. This cotton-like carbon fiber was put into a carding apparatus having a structure as shown in FIG. 4 having a cylinder roll having a diameter of 600 mm to form a sheet-like web made of carbon fiber. The rotation speed of the cylinder roll at this time was 350 rpm, and the speed of the doffer roll was 15 m / min. In this carding process, the carbon fiber was not dropped off or wound around the roll of the carding apparatus. After laminating this web with a cross wrapper, a carbon fiber nonwoven fabric having a needle punch of 50 / cm 2 was obtained. The swing width of the cross wrapper at this time was 1.2 m, and the winding speed of the carbon fiber nonwoven fabric was 1 m / min. The degree of orientation of this carbon fiber nonwoven fabric was 2.2. A plurality of carbon fiber nonwoven fabrics are laminated at 0 ° / 90 °, impregnated with nylon 6 resin (“CM1001”, manufactured by Toray Industries, Inc.) as a base resin, and 200 × 300 × 2 mmt of fiber volume content Vf 30%. A CFRP sheet as a fiber reinforced thermoplastic resin substrate A was produced. After heating the produced CFRP sheet (base material) in a preheating furnace until the center temperature reaches 260 ° C., two CFRP sheets 52 are stacked on a mold 51 adjusted to 150 ° C. as shown in FIG. Then, the center of the cavity 53 was charged, and press molding with bare flow was performed at a pressure of 15 MPa.

  In this press molding, the fluidity was evaluated by ◯ when the substrate was completely filled in the cavity and x when unfilled.

  For the evaluation of formability, two CFRP sheets prepared were heated in a preheating furnace until the center temperature reached 260 ° C., and then two sheets were stacked on a mold temperature-controlled at 150 ° C. and charged in the center of the cavity. When the press molding is performed at a pressure of ○, the total of the press time and cooling time after the mold lowering is finished is within 60 seconds. Those that did not, or those that caused large deformations were judged as x.

  Table 1 shows the conditions of Example 1 and the evaluation results of press molding.

Examples 2-5
Compared to Example 1, in Example 2, the bending stiffness of the reinforcing fiber (carbon fiber) was changed, and in Examples 3 and 4, the base resin was changed to polypropylene and PPS (polyphenylene sulfide) and the mold temperature or molding temperature was changed. In Example 5, press molding was performed under the same conditions as in Example 1 by changing the mold temperature and molding temperature and the bending rigidity of the reinforcing fibers (carbon fibers). The press molding conditions and evaluation results are also shown in Table 1.

Comparative Examples 1-4
In Comparative Examples 1, 2, and 4, press molding was performed under the flow condition of the laminar flow as shown in FIG. 2, and in Comparative Example 3 under the flow condition of the fountain flow as shown in FIG. In addition, the manufacturing method of the fiber reinforced thermoplastic resin base material H in the comparative example 3 is as follows. Carbon fiber (“T700S”, manufactured by Toray Industries, Inc., density 1.8 g / cm ³ , diameter 7 μm, number of filaments 24,000) cut to 6 mm, nylon 6 resin (“CM1001”, manufactured by Toray Industries, Inc.) pellets And were kneaded with a twin screw extruder (TEX30α manufactured by Nippon Steel Works) to obtain pellets having a Vf of 30% and a number average fiber length of 0.3 mm. The obtained pellets were hot pressed to obtain a CFRP sheet of 200 × 300 × 2 mmt. Table 1 shows the press molding conditions and evaluation results in Comparative Examples 1 to 4.

  The method for producing a fiber-reinforced resin molded body according to the present invention can be applied to any method for producing a molded body by press molding using a stampable substrate.

DESCRIPTION OF SYMBOLS 1 Reinforcing fiber mat 2 Fiber reinforced resin material 2a Inner layer 3, 4 Mold 5 Cavity 5a Inner surface 6, 7 Mold 8 Fiber reinforced resin material 8a Inner layer 9 Cavity 10, 11 Mold 12 Fiber reinforced resin material 13 Cavity 21 Carding device 22 Cylinder roll 23 Take-in roll 24 Doffer roll 25 Worker roll 26 Stripper roll 27 Feed roll 28 Belt conveyor 29 Discontinuous carbon fiber 30 Sheet-shaped web 41 Measurement sample 42 Base 43 Three-dimensional image data 44 Micro area 45 Scanning line 46 Carbon fiber 51 Mold 52 CFRP sheet 53 Cavity

Claims (11)

  When manufacturing a fiber-reinforced resin molded body by press-molding a fiber-reinforced resin material in which a plurality of reinforcing fiber mats are laminated and impregnated with a thermoplastic resin, in a cavity formed between molds facing each other, press While the tip side portion of the inner layer of the fiber reinforced resin material that is extruded toward the side of the cavity during molding is stuck to the inner surface of the cavity, the subsequent portion of the inner layer is caused to flow to A method for producing a fiber-reinforced resin molded product, characterized by being filled in.   The manufacturing method of the fiber reinforced resin molding of Claim 1 which laminates | stacks each reinforcing fiber mat layer of the said fiber reinforced resin material with the thickness of 0.5 mm or less. The manufacturing method of the fiber reinforced resin molding of Claim 1 or 2 whose bending rigidity (EI) of the reinforced fiber of the said fiber reinforced resin material is 2.8E-7N * cm < ² > or less.   The manufacturing method of the fiber reinforced resin molding in any one of Claims 1-3 whose die temperature at the time of press molding is lower than melting | fusing point of the said thermoplastic resin.   The manufacturing method of the fiber reinforced resin molding in any one of Claims 1-4 which exists in the range whose average fiber length of the reinforced fiber of the said fiber reinforced resin material is 10-50 mm.   The manufacturing method of the fiber reinforced resin molding in any one of Claims 1-5 in which the reinforced fiber of the said fiber reinforced resin material contains at least 1 sort (s) of carbon fiber, glass fiber, and an aramid fiber.   The manufacturing method of the fiber reinforced resin molding in any one of Claims 1-6 which exists in the range whose average diameter of the reinforced fiber of the said fiber reinforced resin material is 1-50 micrometers.   The manufacturing method of the fiber reinforced resin molding in any one of Claims 1-7 which manufactures the said reinforcing fiber mat laminated | stacked as an inner layer of the said fiber reinforced resin material at least by the carding method.   The manufacturing method of the fiber reinforced resin molding of Claim 8 whose orientation degree of the reinforcing fiber mat manufactured by the said carding method is 1.5 or more.   The manufacturing method of the fiber reinforced resin molding in any one of Claims 1-9 which laminates | stacks at least 2 layers of the reinforced fiber mat of the said fiber reinforced resin material at 0/90 degree.   The manufacturing method of the fiber reinforced resin molding in any one of Claims 1-10 which manufactures the reinforced fiber mat laminated | stacked as the outermost layer of the said fiber reinforced resin material by a papermaking method.

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