JP2008162154A - Manufacturing method of fiber-reinforced plastics, resin for fiber-reinforced plastics and fiber-reinforced plastics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin, for fiber-reinforced plastics, which can reduce the incidence of voids generated in a reinforcing fiber cloth impregnated with the resin by effectively deaerating inside the reinforcing fiber cloth. <P>SOLUTION: The resin 10 for fiber-reinforced plastics includes at least, an uncured heat-curable resin 11 with which the reinforcing fiber cloth is impregnated, as a main material. The resin 10 possesses the dilatancy property at less than the specified temperature Tc, in the "uncured" state of the heat-curable resin 11. However, the resin 10 indicates at least, the thixotropicity at the specified temperature Tc or higher. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a fiber reinforced plastic in which a fiber is impregnated with a resin, a resin for fiber reinforced plastic, and a fiber reinforced plastic, and in particular, a method for producing a fiber reinforced plastic using a thermosetting resin as the resin, The present invention relates to a fiber reinforced plastic resin and a fiber reinforced plastic.

  Conventionally, fiber reinforced plastics (FRP) made of reinforced fibers and matrix resin (resin) are lighter than metal materials, and contain reinforced fibers and thus have higher mechanical strength and elastic modulus than resin materials. Therefore, it is used in many fields such as aircraft, automobiles, railway vehicles, and ships. In particular, fiber-reinforced plastics using thermosetting resins are often used as structural members because many of them are superior in mechanical properties compared to those using thermoplastic resins.

  The fiber reinforced plastic can be produced by impregnating a reinforcing fiber with an uncured thermosetting resin and heating and curing the impregnated thermosetting resin. As an example of such a manufacturing method, a manufacturing method called an RFI (resin film infusion) method has been proposed (see Patent Document 1). Specifically, the manufacturing method includes a step of laminating an uncured film-like thermosetting resin and a reinforcing fiber cloth on a mold, and a sealed space with respect to the thermosetting resin and the reinforcing fiber cloth. A step of covering the back film to form a film, a step of evacuating the sealed space formed by the mold and the back film with a suction device, and a thermosetting resin on the reinforcing fiber cloth in the evacuated space At least a step of impregnating the resin by heating and a step of further curing the resin by further heating the uncured thermosetting resin after the impregnation under a temperature condition at which the resin is cured.

As described above, since the method for producing fiber reinforced plastic uses a film-like thermosetting resin, for example, a low-viscosity liquid thermosetting resin is injected into a molding in which laminated reinforcing fiber cloths are arranged. Compared to the RTM (resin transfer molding) method for manufacturing fiber reinforced plastics, there is no resin to be discarded, and there is less labor for soiling and resin preparation at the work site. Can be manufactured.
JP 2003-11231 A

  However, the fiber reinforced plastic produced by the RFI method may impregnate the reinforcing fiber cloth with a part of the resin before impregnating the uncured thermosetting resin. A plurality of voids (holes) are formed inside the plastic, which may reduce the mechanical strength of the fiber-reinforced plastic.

  Specifically, as shown in FIG. 8A, when the air in the reinforcing fiber cloth 20 is sucked in the evacuation step, along the flow of the fibers of the reinforcing fiber cloth 20 (in the drawing, The gap between the fibers formed (along the white arrow) acts as a degassing path. However, a portion 70a of the uncured thermosetting resin may flow due to the suction force and impregnate the reinforcing fiber cloth 20 during suction, and the impregnation of the resin may block a part of the deaeration path. is there. In this case, the air in the reinforcing fiber cloth 20 may remain without being completely deaerated due to the blockage of the deaeration path. Due to such remaining air, a plurality of voids B are formed in the cured resin 71 and the reinforcing fiber cloth 20 as shown in FIG.

  Further, when the uncured film-like thermosetting resin and the reinforcing fiber cloth are laminated on the mold, the operator may be slightly pressurized from the thermosetting resin toward the reinforcing fiber cloth. . Such pressurization aligns the directions of the molecules of the thermosetting resin, the resin tends to flow in the pressurization direction, and a part of the resin may impregnate the reinforcing fiber cloth. As a result, as described above, a part of the degassing path formed in the fiber gap of the reinforcing fiber cloth is blocked by a part of the resin, and a void is formed in the fiber reinforced plastic.

  The present invention has been made in view of the above-described problems. The object of the present invention is to efficiently deaerate the air in the reinforcing fiber cloth so that the voids in the reinforcing fiber cloth impregnated with the resin are removed. An object of the present invention is to provide a fiber reinforced plastic manufacturing method, a fiber reinforced plastic resin, and a fiber reinforced plastic capable of reducing the generation.

  In order to solve the above problems, a method for producing a fiber-reinforced plastic according to the present invention includes a step of placing a resin containing at least an uncured thermosetting resin as a main material and a reinforcing fiber cloth in a mold, A step of covering the reinforcing fiber cloth and the resin with a back film; a step of evacuating the space formed by the mold and the back film; and heating the resin to evacuate the vacuum. A method for producing a fiber reinforced plastic comprising at least a step of impregnating the resin into the reinforcing fiber cloth in the space, and a step of curing the resin after the impregnation by heating under a temperature condition at which the resin is further cured. In the manufacturing method, the resin has a dilatancy characteristic at a temperature lower than a predetermined temperature, and at least a chimney at a temperature higher than the predetermined temperature. Using a resin having a tropic property, performing the evacuation step from the placement step at least under a temperature condition lower than the predetermined temperature, and in the impregnation step, the heating is performed at a temperature equal to or higher than the predetermined temperature. And it is performed under temperature conditions below the temperature which the thermosetting of the said resin starts.

  According to the method for producing a fiber reinforced plastic according to the present invention, the resin has dilatancy characteristics by performing the placement step and the step of covering the back film under a temperature condition of at least room temperature to a predetermined temperature. Thus, even when the resin is pressurized by the operator, it is possible to reduce the impregnation of a part of the resin into the reinforcing fiber cloth. Furthermore, since the evacuation step is similarly performed under a temperature condition lower than the predetermined temperature, it is possible to reduce the impregnation of the reinforcing fiber cloth with a part of the resin. As a result, since the deaeration path between the fibers of the reinforcing fiber cloth is hardly blocked during the evacuation, it is possible to reduce the remaining air in the thermosetting resin and the reinforcing fiber cloth. . Furthermore, in the step of impregnating the resin, the resin has thixotropic characteristics by heating the resin under a temperature condition equal to or higher than the predetermined temperature and at least a temperature condition lower than a temperature at which the thermosetting of the resin starts. Thus, the resin can be reliably impregnated into the reinforcing fiber cloth. As a result, voids formed in the fiber reinforced plastic can be reduced.

  Here, the “resin having a dilatancy characteristic” in the present invention is a resin that exhibits a dilatancy behavior when stress is applied to the resin. Specifically, the shear rate acting on the resin is increased. As a result, the rate of increase in the shear stress of the resin increases. As a result, even when the shear rate is the same, the viscosity of the resin that exhibits higher viscosity than the Newtonian fluid (increases the apparent viscosity) is increased. That means. The dilatancy is also called reverse thixotropy.

  In addition, the “resin having thixotropic characteristics” in the present invention is a resin that exhibits thixotropic behavior when stress is applied to the resin. Specifically, the shear rate acting on the resin is increased. As a result, the increase rate of the shear stress of the resin decreases, and as a result, the resin having the property of exhibiting a lower viscosity than the Newtonian fluid (decreasing the apparent viscosity) even at the same shear rate. That means.

  As described above, an uncured thermosetting resin has a dilatancy characteristic as a resin having two properties having a dilatancy characteristic below a predetermined temperature and having at least a thixotropic characteristic above the predetermined temperature. However, it can be achieved by adding a substance having thixotropic properties by heating, and the substance is not particularly limited.

  However, as a more preferred embodiment, the resin used by the method for producing a fiber-reinforced plastic according to the present invention is a resin containing a powdered resin in an uncured thermosetting resin, and the powdered resin is at least It melts (melts) above the predetermined temperature.

  By using the powdery resin, it has dilatancy characteristics below a predetermined temperature. That is, under the above temperature conditions, the powdery resin does not melt, so the apparent viscosity of the resin increases, and even when the resin is pressurized, the uncured thermosetting resin is powdered. Therefore, it is possible to suppress the phenomenon that the thermosetting resin easily flows when the directions of the molecules of the uncured thermosetting resin are aligned in the pressurizing direction. As a result, during the process from placing the resin in the mold to the evacuation process, one of the uncured thermosetting resins is affected by the pressure applied by the operator and the pressure during evacuation. It is possible to prevent the portion from being impregnated into the reinforcing fiber cloth. Furthermore, in the step of impregnating the resin, by heating the resin to the predetermined temperature or more, the powdery resin is dissolved in the uncured thermosetting resin, and the resin can have thixotropic characteristics. .

  Moreover, in the case of the said aspect, the temperature which the thermosetting of resin starts is a temperature which the hardening of a thermosetting resin starts after the said resin of a powder fuse | melts, and a powdery resin is also a thermosetting resin. In this case, the temperature is such that curing of both resins begins. Further, when the temperature is equal to or higher than the temperature at which the thermosetting starts, the resin hardly flows, and thus it is difficult to efficiently impregnate the reinforcing fiber cloth with the resin.

  In the method for producing a fiber-reinforced plastic according to the present invention, in the step of impregnating the resin, the temperature condition of heating the resin is a temperature at which the viscosity of the resin that changes when the resin is heated becomes a minimum viscosity value. More preferably.

  According to the present invention, by impregnating the resin under the above temperature condition, the resin having thixotropy characteristic is most easily flowable, so that the reinforcing fiber cloth can be impregnated with the resin quickly and more reliably.

  The method for producing a fiber reinforced plastic according to the present invention includes the step of laminating the reinforcing fiber cloth and a film-like resin as the resin in the step of arranging the resin and the reinforcing fiber cloth in a mold. More preferably, the arrangement is performed.

  According to the present invention, fiber reinforced plastic is molded by the RFI (resin film infusion) method, which is a method of molding fiber reinforced plastic by laminating a reinforced fiber cloth and a film-like resin. Each reinforcing fiber cloth can be uniformly impregnated with a film-like resin disposed between the reinforcing fiber cloths.

  Furthermore, a fiber-reinforced plastic resin is also disclosed as the present invention. The resin for fiber-reinforced plastic according to the present invention is a resin for fiber-reinforced plastic containing at least a main material of an uncured thermosetting resin for impregnating the reinforcing fiber cloth, and the resin is the thermosetting resin. In an uncured state, it has a dilatancy characteristic below a predetermined temperature, and has at least a thixotropic characteristic above the predetermined temperature.

  When the resin according to the present invention is used for the production of fiber reinforced plastic, as described above, the generation of voids in the fiber reinforced plastic can be reduced by efficiently degassing the air in the reinforced fiber cloth. Therefore, a high-quality fiber reinforced plastic can be obtained.

  The resin for fiber-reinforced plastic according to the present invention is a resin containing a powdered resin in an uncured thermosetting resin, and the powdered resin is more preferably melted at the predetermined temperature or more. Furthermore, it is more preferable that the thermosetting resin has a viscosity capable of maintaining a film-like shape at least at room temperature or higher and lower than the predetermined temperature.

  According to the present invention, since the resin can maintain a film-like shape at least at room temperature or higher and lower than a predetermined temperature, the thermosetting resin and the film-like resin can be easily laminated and manufactured. The handling ability of the operator in the process is also improved. The “viscosity capable of maintaining a film-like shape” in the present invention is the viscosity of a so-called RFI resin. Specifically, it is an uncured thermosetting that is semisolid and hardly flows at room temperature. Refers to the viscosity of the adhesive resin.

  More preferably, the predetermined temperature is a temperature at which the resin has a minimum viscosity from 40 ° C., and in such a temperature range, the powdery resin melts and has a lower viscosity than the resin in other temperature ranges. Therefore, a resin having thixotropy characteristics can be easily obtained by applying a slight heat to the resin at room temperature.

  Among such resins used in the production of fiber reinforced plastics, uncured thermosetting resins include vinyl ester resins, epoxy resins, phenol resins, bismaleimide resins, BT resins, cyanate ester resins, benzoxazine resins, and the like. Examples of the resin in which a predetermined amount of a curing agent is added to the resin include a solid thermosetting resin such as an acrylic type or a polyester type in addition to the resin, and dilatancy under the above temperature conditions. If it can have a characteristic and a thixotropy characteristic, it will not specifically limit. In addition, as shown above, when a resin having a thermosetting property is used as a powdered resin, the thermosetting resin has good compatibility with the thermosetting resin at the time of melting, and does not contain a powdery resin. Thus, it is possible to ensure the same mechanical strength as that of the fiber-reinforced plastic having no voids.

  As a more preferable combination of the thermosetting resin and the powder resin, the thermosetting resin is an epoxy resin, and the powdery resin is a solid epoxy resin. By heating to about 100 ° C. with such a combination of resins, the solid epoxy resin melts, so that a resin having thixotropy characteristics can be easily obtained. Moreover, since the same kind of epoxy resin is used for the thermosetting resin and the powder resin, the resin in the fiber reinforced plastic after the thermosetting process is stable in physical properties.

  Further, as the reinforcing fiber constituting the fiber reinforced plastic manufactured using the resin as described above, a woven fabric or a non-woven fabric can be cited, and the fiber reinforced plastic has a cloth shape, and in the vacuum drawing process, There is no particular limitation as long as the fiber structure is less likely to form voids. More preferably, in the fiber reinforced plastic according to the present invention, it is more preferable that the reinforcing fiber cloth constituting the fiber reinforced plastic is made of a woven reinforcing fiber cloth. The weaving method may be a woven structure such as plain weave, twill weave, satin weave, etc., and a plurality of layers in which carbon fibers are aligned in one direction intersect so that the fiber axes of adjacent layers are shifted by about 30 ° to 90 °. A so-called multiaxial fiber structure may be used.

  Further, the fibers of the reinforcing fiber cloth constituting the fiber reinforced plastic manufactured as described above include glass fibers, carbon fibers, aramid fibers, alumina fibers, boron fibers, steel fibers, PBO fibers, or high-strength polyethylene fibers. A fiber is mentioned, and the fiber is not particularly limited. However, when the epoxy resin is used, it is more preferable to use carbon fiber. That is, among such fiber reinforced plastics, carbon fiber reinforced plastic (CFRP) made of epoxy resin and carbon fiber can achieve the most weight reduction. Furthermore, carbon fibers are superior in specific strength and specific rigidity compared to other fibers, and are compatible with epoxy resins, so that high-performance fiber-reinforced plastics can be obtained.

  According to the present invention, by efficiently degassing the air in the reinforcing fiber cloth, the generation of voids in the reinforcing fiber cloth impregnated with the resin can be reduced, and the mechanical strength of the fiber reinforced plastic is ensured. can do.

  Hereinafter, an embodiment of a resin for fiber-reinforced plastic according to the present invention and a manufacturing method suitable for manufacturing the fiber-reinforced plastic will be described with reference to the drawings.

  FIG. 1 is a schematic conceptual view of a fiber reinforced plastic resin according to the present embodiment, and FIG. 2 shows the flow characteristics of the fiber reinforced plastic resin shown in FIG. 1 in terms of shear rate and shear stress acting on the resin. FIG. 3 is a diagram for explaining the viscosity of the resin with respect to the temperature of the resin when the fiber-reinforced plastic resin according to this embodiment is heated.

  As shown in FIG. 1, the fiber reinforced plastic resin according to the present embodiment includes at least a main component of an uncured epoxy resin (thermosetting resin) 11 for impregnating a carbon fiber cloth (reinforced fiber cloth). This is a resin 10 for carbon fiber reinforced plastic (CFRP). The resin 10 includes an uncured epoxy resin 11 and a powdered solid epoxy resin 12. Moreover, the uncured epoxy resin 11 has a viscosity capable of maintaining a form-like shape at least at room temperature, and is called a so-called RIF resin. Further, the solid epoxy resin 12 exists in a solid state when the temperature is lower than the predetermined temperature Tc from room temperature, and is further configured to melt when the temperature is equal to or higher than the predetermined temperature Tc.

  Thus, by including the solid epoxy resin 12, the resin 10 becomes a resin 13 having a dilatancy characteristic under a temperature condition lower than a predetermined temperature Tc. Specifically, as shown in FIG. 2, when the temperature T of the resin 10 is lower than a predetermined temperature Tc, the shear stress acting on the resin 10 increases as the shear rate acting on the resin 10 increases. Compared with this, it shows an increase in dilatancy behavior. More specifically, under the above temperature conditions (T <Tc), the powdered solid epoxy resin 12 does not melt, so the apparent viscosity of the resin increases and the resin 10 is pressurized. However, the presence of the powdered solid epoxy resin 12 makes it possible to prevent the molecules of the uncured thermosetting resin 11 from being aligned in the flow direction.

  In addition, since the resin 10 is an epoxy resin for both the thermosetting resin and the powdery resin as the main material, as shown in FIG. 3, the resin 10 is less than the predetermined temperature Tc. The resin has a higher resin viscosity than other temperature region resins of the uncured resin.

  On the other hand, the resin 10 melts into a resin 14 having thixotropy characteristics under a temperature condition that is equal to or higher than a predetermined temperature Tc and lower than the thermosetting start temperature Ts. Specifically, when the temperature T of the resin 10 is equal to or higher than the predetermined temperature Tc and lower than the thermosetting start temperature Ts, as shown in FIG. 2, even if the shear rate acting on the resin 10 increases, the resin 10 10 expresses a thixotropic behavior in which the shear stress does not increase as compared to the Newtonian fluid. In addition, since the resin 10 is an epoxy resin for both the thermosetting resin and the powdery resin, which are the main materials, as shown in FIG. 3, the resin 10 has a predetermined temperature Tc or higher and a thermosetting start temperature Ts. Under the above thermal conditions, the resin 10 has the lowest viscosity temperature Tmin that is the lowest viscosity point at which the lowest viscosity value is obtained. Further, the powdered solid epoxy resin 12 dissolves in the same quality uncured epoxy resin under the temperature condition, and the resultant fiber reinforced plastic is materially stable.

  A method for producing a fiber reinforced plastic using the carbon fiber reinforced plastic (CFRP) resin will be described below with reference to FIG.

  First, as shown in FIG. 4A, as a fiber-reinforced plastic resin, a film-like resin 10 having a dilatancy characteristic below a predetermined temperature Tc and at least a thixotropy characteristic above the predetermined temperature Tc. And the woven reinforcing fiber cloth 20 are sequentially laminated at least in the temperature condition where the temperature T of the resin 10 is equal to or higher than room temperature RT and lower than the predetermined temperature Tc, and is disposed in the mold 41 (step a). .

  Next, as in the step shown in FIG. 4B, the back film 43 is covered with respect to the reinforcing fiber cloth 20 and the resin 10 under the temperature condition (RT ≦ T <Tc), and the sealed space S is formed by the sealing material 42. Form (step b). Further, as in the step shown in FIG. 4C, the suction device 44 applies the temperature condition (RT ≦ T <Tc) to the sealed space S formed by the mold 41 and the back film 43. (Step c).

  As described above, since the steps a to c are performed under the temperature condition (RT ≦ T <Tc) (see FIG. 3), the resin 10 has dilatancy characteristics, as shown in FIG. In addition, even when the resin 10 is pressurized or vacuum sucked, the impregnation of a part of the resin 10 into the reinforcing fiber cloth 20 can be reduced. As a result, since it is possible to suppress clogging of a part of the deaeration paths between the fibers of the reinforcing fiber cloth 20 from the process a to the process c, the air in the thermosetting resin and the reinforcing fiber cloth can be suppressed. The remaining amount can be reduced.

  Further, as shown in FIG. 4D, the resin 10 is heated under a temperature condition in which the temperature T of the resin 10 is equal to or higher than a predetermined temperature Tc and lower than the temperature Ts at which the resin 10 starts thermosetting. (Step d). Specifically, as shown in FIG. 3, heating is performed at the temperature condition for heating the resin 10 and at a temperature Tmin at which the viscosity of the resin 10 that changes when the resin 10 is heated becomes the minimum viscosity value νmin. Under such temperature conditions (T = Tmin in the temperature range of Tc ≦ T <Ts), the powdered solid epoxy resin 12 melts, and the resin 10 exhibits thixotropic behavior and the resin 10 Has the lowest viscosity. As a result, as shown in FIG. 5B, the reinforcing fiber cloth 20 in the evacuated space is easily impregnated with the resin 10, and an uncured fiber reinforced plastic 30A having almost no voids can be obtained. .

  Then, the resin is cured by further heating the uncured thermosetting resin 30A after impregnation (at a temperature condition equal to or higher than the resin curing start temperature Ts) under a temperature condition at which the resin is cured (step e), and then cooled. A fiber reinforced plastic 30B is obtained. Since the fiber reinforced plastic 30B thus obtained has almost no voids, high mechanical strength can be ensured.

An example is shown below based on this embodiment.
(Example)
<Resin>
As an uncured thermosetting resin, an epoxy resin (Epicronlon 840: manufactured by Dainippon Ink & Chemicals) and a solid epoxy resin (Epicronlon HP4700) having a melting temperature of 50 ° C. or higher (about 100 ° C.) as a powdered resin. : Dai Nippon Ink Chemical Co., Ltd.) and diaminodiphenylmethane as a curing agent for these epoxy resins are mixed in a ratio of 70:30:29 to produce a film-like resin of 300 mm × 300 mm and 0.2 mm thickness. did.

<Reinforcing fiber cloth>
Preparation of carbon fiber cloth of 300 mm × 300 mm thickness 0.3 mm, in which carbon fiber yarns made of carbon fiber bundles having an elliptical cross section of 0.25 mm in the vertical axis and 3.0 mm in the horizontal axis made of carbon fiber are arranged in a multiaxial shape. did.

<Production of fiber reinforced plastic>
At room temperature, the film-like resin and the carbon fiber cloth are sequentially laminated in a mold under room temperature conditions, and the back film is covered with these laminates, and a sealed space formed by the mold and the back film. Was sucked by a suction device under the condition of pressure -95 kPa.

  Next, in this state, these laminates were heated so that the film-like resin became 50 ° C., and the carbon fiber cloth was impregnated with the resin. Further, the impregnated resin was heated to 130 ° C., and the impregnated resin was cured to produce a fiber reinforced plastic.

<Evaluation 1>
The resin was heated to 50 ° C., and the relationship between shear stress and shear rate was measured using a viscosity measuring device. The result is shown in FIG.

<Evaluation 2>
The cross section of the manufactured fiber reinforced plastic was observed with a microscope. The result is shown in FIG.

(Comparative example)
The difference from the examples is that an epoxy resin (Epiclon® 840: manufactured by Dainippon Ink & Chemicals, Inc.) as a film-like resin and diaminodiphenylmethane as a curing agent for the epoxy resin were mixed in a ratio of 100: 29. Is a point. And while measuring the shear stress and shear rate of this resin on the same conditions as Example 1, the cross section of the fiber reinforced plastic manufactured using this resin was observed with the microscope. The results are shown in FIGS. 6 and 7 (b).

[result]
As shown in FIG. 6, the resin according to the example showed dilatancy behavior, whereas the resin according to the comparative example showed thixotropic behavior. Further, as shown in FIGS. 7A and 7B, the fiber-reinforced plastic according to the manufactured example was not voided, but the comparative example was formed with a plurality of voids.

[Discussion]
From the results shown in FIG. 6, since the resin shown in the comparative example has thixotropic characteristics, a part of the resin is carbon while the carbon fiber cloth and the film-like resin are laminated, the back film is covered, and vacuum suction is performed. It is presumed that the fiber cloth is impregnated, and as a result, the deaeration path is closed during vacuum suction, and air remains in the laminate. As a result, it is considered that voids were formed in the fiber reinforced plastic obtained from the laminate in which air remained.

  On the other hand, since the resin shown in the examples has dilatancy characteristics at room temperature (50 ° C. or less), carbon fiber cloth and a film-like resin are laminated, the back film is covered, and a part of the resin is vacuum sucked. Was not impregnated, it is considered that the voids were reduced as compared with the comparative example. As described above, the resin is not impregnated into the carbon fiber cloth because the powdery solid epoxy resin does not melt under the above temperature condition (room temperature), so that the apparent viscosity of the resin rises and the resin is pressurized. Even in this case, it is considered that the presence of the powdery resin suppresses the alignment of the molecular directions of the uncured thermosetting resin in the flow direction.

  As mentioned above, although embodiment of this invention has been explained in full detail using drawing, a concrete structure is not limited to this embodiment, Even if there is a design change in the range which does not deviate from the gist of the present invention. These are included in the present invention.

  For example, in the fiber reinforced plastic manufacturing method, the step of impregnating the reinforced fiber cloth with the resin and the temperature of curing the thermosetting resin are fixed so as to satisfy the temperature condition, respectively, but the impregnation and curing are performed. If possible, the respective steps may be performed as one step by heating to gradually raise the temperature.

  Further, in the examples, the ratio of the powdered resin to the thermosetting resin is specified, but this ratio may be appropriately determined depending on the type of the reinforcing fiber cloth, the fiber diameter, and the weaving method, and is limited to the above ratio. is not.

  The fiber-reinforced composite material according to the present invention is particularly suitable for structural members that should ensure mechanical strength. Specifically, motorcycles such as motorcycle frames and cowls, doors, bonnets, tailgates, side fenders, side panels, fenders, trunk lids, hardtops, engine cylinder covers, engine hoods, chassis, air spoilers, propeller shafts, etc. Applications for automobile parts.

The schematic conceptual diagram of resin for fiber reinforced plastics concerning the embodiment of the present invention. The figure for demonstrating the flow characteristic of resin for fiber reinforced plastics shown in FIG. 1 with the shear rate and shear stress which act on resin. The figure for demonstrating the resin viscosity with respect to the resin temperature when the fiber reinforced plastic resin which concerns on this embodiment is heated. It is a figure for demonstrating the manufacturing method of the fiber reinforced plastic which concerns on this invention, (a) is the figure which showed the arrangement | positioning process of resin and a reinforced fiber cloth, (b) is the process which covers a back film. (C) is a step of evacuating, (d) is a diagram illustrating a step of impregnating a reinforcing fiber cloth with a resin, and (d) is a diagram illustrating a process of heating the resin after impregnation. The figure for demonstrating the process to harden | cure. It is a figure for demonstrating one process of manufacturing the fiber reinforced plastic which concerns on this embodiment, (a) is a figure for demonstrating the state which is evacuating in the process of vacuuming of a manufacturing method. (B) is a diagram showing the state of the fiber-reinforced plastic after the impregnation step. The figure which measured the flow characteristic of the resin for fiber reinforced plastics concerning an Example and a comparative example. The figure which showed the structure | tissue photograph in the cross section of the fiber reinforced plastic manufactured by the manufacturing method which concerns on an Example and a comparative example. It is a figure for demonstrating a part of process of manufacturing the conventional fiber reinforced plastic, (a) is a figure for demonstrating the state at the time of performing vacuum drawing, (b) is this production The figure which showed the fiber reinforced plastic manufactured by the method.

Explanation of symbols

  10: Resin, 11: Epoxy resin (thermosetting resin), 12: Powdered solid epoxy resin (powdered resin), 13: Resin having dilatancy characteristics, 14: Resin having thixotropic characteristics, 20: Reinforcing fiber cloth, 41: Mold, 43: Back film

Claims (9)

Placing a resin containing at least an uncured thermosetting resin as a main material and a reinforcing fiber cloth in a mold;
Covering the back film against the reinforcing fiber cloth and the resin;
Evacuating the space formed by the mold and the back film;
Impregnating the resin into the reinforcing fiber cloth in the evacuated space by heating the resin; and
A step of curing the impregnated resin by further heating at a temperature condition at which the resin is cured,
The manufacturing method uses, as the resin, a resin having dilatancy characteristics below a predetermined temperature, and at least thixotropic characteristics above the predetermined temperature,
The vacuuming step from the placement step is performed at least under a temperature condition less than the predetermined temperature,
In the impregnation step, the heating is performed under a temperature condition that is equal to or higher than the predetermined temperature and lower than a temperature at which thermal curing of the resin starts.   2. The fiber according to claim 1, wherein the resin is a resin including a powdery resin in an uncured thermosetting resin, and the powdery resin is melted at least at the predetermined temperature or more. A method of manufacturing reinforced plastics.   The temperature condition for heating the resin in the step of impregnating the resin is a temperature at which the viscosity of the resin that changes when the resin is heated is a minimum viscosity value. The manufacturing method of the fiber reinforced plastic as described in 2 ..   The step of arranging the resin and the reinforcing fiber cloth in a mold includes performing the arrangement by sequentially laminating the reinforcing fiber cloth and a film-like resin as the resin. The manufacturing method of the fiber reinforced plastic in any one of 1-3. A fiber reinforced plastic resin containing at least a main material of an uncured thermosetting resin for impregnating a reinforcing fiber cloth,
The resin for fiber-reinforced plastics, wherein the resin has dilatancy characteristics below a predetermined temperature and has at least thixotropic characteristics above the predetermined temperature when the thermosetting resin is uncured.   The fiber reinforced according to claim 5, wherein the resin is a resin including a powdered resin in an uncured thermosetting resin, and the powdered resin is melted at the predetermined temperature or more. Resin for plastic.   The resin for fiber-reinforced plastics according to claim 5 or 6, wherein the thermosetting resin has a viscosity capable of maintaining a film shape at least from room temperature to less than the predetermined temperature.   The fiber-reinforced plastic resin according to any one of claims 5 to 7, wherein the thermosetting resin is an epoxy resin, and the powdery resin is a solid epoxy resin.   A fiber reinforced plastic produced by the method for producing a fiber reinforced plastic according to any one of claims 1 to 4, wherein the reinforced fiber cloth comprises a woven fiber cloth. .

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