JP2007230175A - Manufacturing method of fiber reinforced resin molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a fiber reinforced resin molded article which does not need a prior defoaming of the resin and is able to produce a reinforced resin molded article having a higher Vf and better quality compared with that made by the LRTM method. <P>SOLUTION: A mold 11 in which a reduced pressure channel 15 is formed at the out side of a cavity 14 so as to surround the cavity 14 at the same time the mold is clamped at a state where a member for deaerating 18 is arranged so as to mount the cavity 14 and a part of the reduced pressure channel 15 is used. The inside of the cavity 14 is evacuated through the reduced pressure channel 15 at a state where a reinforcing fiber substrate 30 ia arranged in the cavity 14, at the same time the reinforcing fiber substrate 30 is immersed with a resin by injecting the resin into the cavity 14 through an injecting port 19 communicating to with the cavity 14. The resin is injected into the cavity 14 under the first pressure, after gelation of the resin injected into the cavity 14 started to be gelled, the resin is injected by enhancing the injecting pressure of the resin at the second pressure higher than an injecting pressure in the case of the LRTM method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a fiber reinforced resin molded product, and more particularly to a method for manufacturing a fiber reinforced resin molded product using a mold having a soft pinch-off structure.

  Conventionally, glass fibers, carbon fibers, and the like are listed as reinforcing fibers used in fiber reinforced resin molded products, but carbon fibers have a small specific gravity, high strength, and high elastic modulus, and carbon fibers are reinforcing fibers. Reinforced resin molded products have high specific strength and specific elastic modulus, and have recently begun to be used for general industrial applications such as automobiles, civil engineering and building materials, including aerospace applications.

  In addition, there are various molding methods, and the most suitable molding method has been selected from the required characteristics and manufacturing cost of the molded product. Hand lay-up molding, impregnated with a semi-cured thermosetting resin A prepreg (intermediate base material) laminated and molded by an autoclave is widely used in general industrial applications. And in order to increase productivity, the RTM method that can shorten the molding cycle compared to the conventional autoclave molding method using prepreg, Va-RTM method (vacuum RTM method) that helps the resin impregnation by vacuum suction inside the mold. A molding method in which a preform is molded using a reinforcing fiber base not impregnated with a resin and then the resin is impregnated all at once has become popular.

  In the vacuum RTM method, the resin is injected and impregnated by the pressure difference between the inside and outside of the cavity. Therefore, at the initial stage of injection, the resin is not sufficiently impregnated in the reinforcing fiber base, so the flow resistance is low, and it is vigorous at a high flow rate. Flowing. However, there is a difference in flow resistance between the reinforcing fiber bases depending on the location, and the resin may gel before the resin can be sufficiently impregnated into the entire reinforcing fiber base. As a result, voids (voids not impregnated with resin) are generated. In order to improve this problem, in the vacuum RTM method in which the resin is injected into the cavity using the differential pressure between the internal pressure of the cavity and the external pressure, and the reinforcing fiber base material is impregnated, the injection speed of the resin is set to the differential pressure. There has been proposed a method of injecting resin by decelerating to a flow rate lower than the natural flow rate by (see Patent Document 1).

In addition, an LRTM (Light Resin Transfer Molding) method using a mold having a soft pinch-off structure is also being carried out. The soft pinch-off structure has a decompression passage formed outside the cavity so as to surround the cavity, and the mold is closed with a soft pinch-off cloth disposed across the cavity and a part of the decompression passage. The structure that decompresses the inside of the cavity via In the LRTM method, the inside of the cavity is depressurized through the soft pinch-off cloth in a state where the reinforcing fiber base is arranged in the cavity of the mold having the soft pinch-off structure, and the difference between the reduced pressure inside the cavity and the external pressure The resin is injected into the cavity using pressure to impregnate the reinforcing fiber substrate.
JP 2003-25347 A

  When using a molding die having no soft pinch-off structure and impregnating the reinforcing fiber base with resin by the RTM method, it is necessary to defoam the resin in advance. In addition, even if the resin is defoamed in advance, small bubble portions present in the gaps between the reinforcing fiber bases may become voids, or the bubbles may remain in the mold and cause pits (recesses) in the molded product. .

In the method described in Patent Document 1, the resin injection rate is slowed so that the resin is easily impregnated into the reinforcing fiber base. However, productivity is low due to the slow resin injection rate.
On the other hand, in the LRTM method using a mold having a soft pinch-off structure, bubbles generated in the cavity are discharged from the soft pinch-off cloth portion to the outside of the cavity, so that prior defoaming of the resin becomes unnecessary.

  However, in the vacuum RTM method and the LRTM method, since the resin is injected without being positively pressurized, the resin is reinforced when the reinforcing fiber base material has a high Vf (fiber volume content) of, for example, 60% or more. It becomes difficult to impregnate the entire fiber base material, and it is difficult to obtain a molded body having no unimpregnated portion (void). In addition, after the gelation of the resin injected into the cavity is started, the viscosity of the resin suddenly increases and almost no resin is injected. Therefore, even when a reinforcing fiber base material having a high Vf is used, voids are used. Is likely to occur.

  The present invention has been made in view of the above-described conventional problems, and its object is to eliminate the need for prior defoaming of the resin, and a fiber reinforced resin molded article having a high Vf and good quality as compared with the LRTM method. It is providing the manufacturing method of the fiber reinforced resin molded product which can manufacture.

  In order to achieve the above object, the invention according to claim 1 includes a first mold in which a cavity is formed and a second mold that covers the cavity, and the pressure is reduced so as to surround the cavity outside the cavity. A mold is used in which a passage is formed and the mold is closed in a state where a deaeration member is disposed so as to straddle a part of the cavity and the decompression passage. Then, with the reinforcing fiber base disposed in the mold, the inside of the cavity is depressurized through the pressure reducing passage, and resin is injected into the cavity from the injection hole communicating with the cavity. A resin impregnation step of impregnating the resin with the resin. Then, the resin is injected into the cavity at a first pressure, and after the resin injected into the cavity starts to gel, the injection pressure of the resin is determined from the injection pressure in the LRTM (Light Resin Transfer Molding) method. Pressurize to inject high second pressure.

  Here, the “degassing member” allows passage of gas or low-viscosity liquid between the cavity and the decompression passage even when sandwiched between the first mold and the second mold in the mold closed state. It means a member, and is composed of a woven fabric, a knitted fabric, a non-woven fabric or the like formed of a material insoluble in resin.

  In this invention, the inside of the cavity is depressurized through the depressurization passage in a state where the reinforcing fiber base is disposed in the cavity and the first and second molds are closed. And resin is inject | poured in a cavity from an injection hole. The resin injected into the cavity is impregnated in the reinforcing fiber base and moves while pushing the bubbles remaining in the reinforcing fiber base. The bubbles move from the cavity to the decompression passage through the deaeration member existing across the cavity and the decompression passage. In a state where the viscosity is low, the resin can also pass through the deaeration member. However, when the viscosity becomes high, the passage becomes difficult, and bubbles can mainly pass. Therefore, even if the resin is supplied without degassing in advance, the bubbles generated from the resin are smoothly discharged out of the cavity. Until the gelation of the resin injected into the cavity is started, the resin is injected at a first pressure equivalent to the LRTM method, for example, 0.1 MPa to 1 MPa, and the resin injected into the cavity is gelled. Is started, the pressure is increased to a second pressure higher than the injection pressure in the LRTM method and injected. Accordingly, the resin is injected even in a state where the resin has a high viscosity and the LRTM method or the vacuum RTM method can hardly inject the resin. As a result, the resin is easily impregnated in the non-impregnated portion of the reinforcing fiber base, and a fiber reinforced resin molded article having a high Vf and good quality can be manufactured as compared with the LRTM method.

  According to a second aspect of the present invention, in the first aspect of the present invention, the injection pressure is increased to the second injection pressure when a predetermined time elapses from the start of the resin injection. Therefore, according to the present invention, it is easy to determine the appropriate time to increase the injection pressure from the first pressure to the second pressure by measuring the elapsed time from the start of injection without actually detecting the state of the resin in the cavity. Can be set to

  According to a third aspect of the invention, in the first or second aspect of the invention, the second injection pressure is maintained even after the gelation time necessary for the gelation of the resin injected into the cavity. Hold for a preset time. Here, the “preset time” means a time during which the resin can be effectively injected in order to compensate for the curing shrinkage of the resin after the gelation is completed.

  Even when the gelation is completed, the curing of the resin is not completed, and curing shrinkage occurs as the curing proceeds. If the amount of cure shrinkage is small, there is no problem, but if the amount of cure shrinkage is large, pits (concave portions) and shrinkage occur on the surface of the molded product. However, in this invention, since the second injection pressure is maintained even after the completion of gelation, the resin is injected into the cavity to compensate for the shrinkage when the amount of cure shrinkage is large, and the surface of the molded product Occurrence of pits (concave portions) and shrinkage is suppressed.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the second pressure is a resin from the start of gelation to the completion of curing. This is a pressure at which bubbles inside can pass through the deaeration member. In the present invention, bubbles generated between the start of gelation and the completion of curing can be discharged out of the cavity.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein a plurality of the deaeration members are provided, and each of the deaeration members is an inlet of the injection hole. The distance from each other is equal and symmetrical. In this invention, compared with the case where one deaeration member is provided, or when a plurality of deaeration members are arranged asymmetrically at different distances from the inlet, the resin is in the reinforcing fiber base 30. It becomes easy to impregnate uniformly.

  According to the present invention, there is provided a method for producing a fiber reinforced resin molded product that does not require prior defoaming of the resin and can produce a fiber reinforced resin molded product having a high Vf and good quality as compared with the LRTM method. can do.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
A mold having a soft pinch-off structure is used for the production of a fiber reinforced resin molded product, as in the LRTM (Light Resin Transfer Molding) method. As shown in FIGS. 1 and 2, the mold 11 includes a lower mold 12 as a first mold and an upper mold 13 as a second mold. One of the lower mold 12 and the upper mold 13 is a fixed mold and the other is a movable mold. FIG. 1A is a schematic plan view of the mold 11 from which the upper mold 13 is omitted.

  The lower die 12 and the upper die 13 are formed in a substantially rectangular shape on the plane, and the lower die 12 includes a cavity 14 having a substantially rectangular shape corresponding to the shape of the fiber-reinforced resin molded product to be formed and surrounds the cavity 14. An annular decompression passage 15 is formed in the upper part. On the upper surface of the lower mold 12, annular grooves 16a and 16b are formed inside and outside the decompression passage 15, and sealing materials 17a and 17b are accommodated in the annular grooves 16a and 16b, respectively. O-rings are used as the sealing materials 17a and 17b. A plurality of deaeration members (soft pinch-off cloths) 18 are disposed on the upper surface of the lower mold 12 so as to straddle part of the cavity 14 and the decompression passage 15. In this embodiment, the deaeration members 18 are arranged symmetrically at four locations near each corner of the cavity 14.

  The deaeration member 18 has a function of allowing a gas or a low-viscosity liquid to pass between the cavity 14 and the decompression passage 15 even when sandwiched between the lower mold 12 and the upper mold 13 in the mold closed state. For example, it is composed of a woven fabric, a knitted fabric, a nonwoven fabric or the like formed of a material insoluble in an uncured resin. Although there is no restriction | limiting in particular as a material of the member 18 for deaeration, Glass fiber and carbon fiber are preferable. The decompression passage 15 and the deaeration member 18 constitute a soft pinch-off structure.

  The lower mold 12 is provided with a temperature adjusting unit (not shown) that adjusts the temperature of the lower mold 12. For example, the temperature adjustment unit includes a passage through which the heat medium flows, and the temperature of the lower mold 12 can be adjusted by changing the temperature of the heat medium supplied to the passage.

  As shown in FIG. 2, an injection hole 19 and a discharge hole 20 are formed in the upper mold 13, and the injection hole 19 is formed at a position where one end of the injection hole 19 a corresponds to the center of the cavity 14. That is, as shown in FIG. 1A, in this embodiment, the distances from the inlet 19a to the four deaeration members 18 are configured to be equal. The discharge hole 20 has a decompression port 20 a at one end formed at a position corresponding to the decompression passage 15.

  The injection hole 19 is connected to a resin injection device 22 through an injection tube 21. A known device is used for the resin injection device 22 and is configured to pump out the resin stored in the tank. A syringe pump is used as a pump, and is configured to be able to pressurize the resin and deliver it in a fixed amount. The discharge hole 20 is connected to the decompression pump 24 via the suction pipe 23. The injection pipe 21 is provided with an opening / closing valve 25, and a pressure gauge 26 is provided closer to the cavity 14 than the opening / closing valve 25. The suction pipe 23 is provided with an opening / closing valve 27, and a trap 28 is provided closer to the decompression pump 24 than the opening / closing valve 27.

  The resin injection device 22, the pressure reducing pump 24, and the on-off valves 25 and 27 are controlled or operated in accordance with commands from a control device (not shown). Further, a temperature sensor (not shown) for detecting the temperature of the lower mold 12 and a detection signal of the pressure gauge 26 are input to the control device. The control device adjusts the temperature of the lower mold 12 based on the detection signal of the temperature sensor.

  1 and 2 schematically show the configuration of the mold 11, and for the sake of illustration, in order to exaggerate some dimensions and make them easy to understand, the width and length of each part are shown. The ratio of dimensions such as thickness and thickness is different from the actual ratio.

Next, the manufacturing method of a fiber reinforced resin molded product is demonstrated.
As the reinforcing fiber substrate, for example, a woven fabric, a knitted fabric, a nonwoven fabric laminate or a three-dimensional woven fabric, a three-dimensional knitted fabric, and a braid made of glass fiber, carbon fiber, aramid fiber or the like is used. As the resin, a thermosetting resin such as an unsaturated polyester resin, an epoxy resin, or a phenol resin is used.

  When manufacturing a fiber reinforced resin molded product, first, the reinforcing fiber base 30 is disposed in the cavity 14 of the lower mold 12, the mold 11 is clamped, and the temperature of the mold 11 is maintained at a predetermined temperature. Then, the pressure reducing pump 24 is driven in a state where the on-off valve 25 is closed and the on-off valve 27 is opened, so that the inside of the cavity 14 is decompressed to a state close to a vacuum. Subsequently, in a state where the inside of the cavity 14 is decompressed, a resin impregnation step is performed in which the on-off valve 25 is opened and a resin to which a curing agent is added from the resin injection device 22 is injected into the cavity 14 from the injection port 19a.

  The resin injection device 22 delivers the resin so that the injection pressure is a first pressure (low pressure) of 0.1 MPa to 1 MPa, preferably 0.1 MPa to 0.5 MPa, and a constant flow rate. Here, the injection pressure means the pressure of the resin delivered from the resin injection device 22 and corresponds to the detected pressure of the pressure gauge 26. The flow rate of the resin is set to a value at which the resin is filled in the cavity 14 when gelation of the resin injected into the cavity 14 is started. This flow rate is determined in advance by a test. The resin injected into the cavity 14 is impregnated in the reinforcing fiber base 30 and moves while pushing the bubbles remaining in the reinforcing fiber base 30. Then, the resin gradually fills the cavity 14 from the bottom, the bubbles move to the upper side of the cavity 14, passes through the deaeration member 18 that exists across the cavity 14 and the decompression passage 15, and from the cavity 14 to the decompression passage 15. Move to.

  The injection of the resin into the cavity 14 is continued, and the gelation of the resin in the cavity 14 is started when a predetermined time has elapsed from the start of the injection. When the gelation is started, the viscosity of the resin in the cavity 14 suddenly increases, and the resin is injected even if the resin is supplied from the resin injection device 22 at the first pressure equivalent to the LRTM method. It becomes almost impossible. However, in this embodiment, after the gelation is started, the resin is pressurized and injected by the resin injection device 22 to a second pressure (for example, 6 MPa) higher than the injection pressure in the LRTM method. The second pressure is a pressure at which bubbles in the resin from the time when the resin starts to gel until the curing is completed can pass through the degassing member. Accordingly, the resin is injected even in a state where the resin has a high viscosity and the LRTM method or the vacuum RTM method can hardly inject the resin. In the state where the viscosity is low, the resin can also pass through the deaeration member 18, but when the viscosity becomes high, the passage becomes difficult, and bubbles can mainly pass through. Therefore, even if the resin is supplied without defoaming in advance, bubbles generated from the resin are smoothly discharged out of the cavity 14.

  The control device does not directly detect that gelation has started and does not increase the pressurization by the resin injecting device 22, but the second injecting pressure is applied when a predetermined time has elapsed since the start of injecting the resin. A command signal is output to the resin injection device 22 so as to increase the pressure. The predetermined time is obtained in advance by a test and stored in the storage device of the control device.

  The resin injection device 22 holds the second injection pressure for a preset time even after the gelation time necessary for the gelation of the resin injected into the cavity 14 has elapsed. Thereafter, the on-off valves 25 and 27 are closed, and the operation of the resin injection device 22 and the decompression pump 24 is stopped. Here, the “preset time” means a time during which the resin can be effectively injected in order to compensate for the curing shrinkage of the resin after the gelation is completed, and is set by a test in advance. Even when the gelation is completed, the curing of the resin is not completed, and curing shrinkage occurs as the curing proceeds. If the amount of cure shrinkage is small, there is no problem, but if the amount of cure shrinkage is large, pits (concave portions) and shrinkage occur on the surface of the fiber-reinforced resin molded product. However, by maintaining the second injection pressure after the completion of gelation, the resin is injected so as to compensate for the shrinkage when the amount of cure shrinkage is large, and pits (recesses) and shrinkage are formed on the surface of the molded product. Occurrence is suppressed.

After the resin is completely cured, the mold 11 is opened, and the fiber-reinforced resin molded product is removed from the mold 11.
The pressure change from the start of resin injection to the stop of resin injection is, for example, as shown in FIG. Since the resin is injected so that the flow rate is constant, the pressure gradually increases as the resin is injected into the cavity 14. And after a pressure rises rapidly from the time of gelatinization being started, it becomes a fixed pressure.

  300 mm × 500 mm × 5 mm size three-dimensional woven fabric as reinforcing fiber substrate 30, resin as main component is bisphenol A type epoxy resin, curing agent is aliphatic polyamine, reactive diluent is 1,4 butanediol diglycidyl A solution consisting of ether was used. And as a 1st Example, about the reinforcement fiber base material 30 whose Vf is 45%, injection | emission speed | velocity | rate of 4 ml / sec and pressure holding time (time hold | maintained at the 2nd pressure after the start of gelatinization) 5 minutes A reinforced resin molded product was manufactured, and as a second example, a fiber reinforced resin molded product was manufactured under the conditions of an injection rate of 8 ml / second and a pressure holding time of 5 minutes for a reinforced fiber substrate 30 having a Vf of 45%. Further, as a comparative example, a fiber reinforced resin molded product was manufactured under the same conditions as in the first example except that the pressure was not increased to the second pressure after the start of gelation. And the external appearance was visually evaluated about the fiber reinforced resin molded product of 1st and 2nd Example, and the fiber reinforced resin molded product of a comparative example.

The evaluation criteria were the following criteria with a maximum score of 5 points.
5 points: No defects (dry spots, bubbles, etc.) 4 points: Defect region less than 1.0% 3 points: Defect region 1.0% or more and less than 5% 2 points: Defect region 5.0% or more and less than 10.0% 1 point: Less than 10.0% of defect area As a result, the evaluation score was 4 in the first example, 3 in the second example, and 2 in the comparative example. From the first example and the comparative example, it was confirmed that the quality was improved by increasing the injection pressure to the second pressure after the start of gelation. In addition, according to the first example and the second example, it was confirmed that the quality was improved when the resin injection rate was slower.

According to this embodiment, the following effects can be obtained.
(1) In a state where the reinforcing fiber base 30 is disposed in the cavity 14 of the mold 11 having the soft pinch-off structure, the resin is injected at a pressure equivalent to that of the LRTM method, and the pressure in the cavity 14 is reduced through the pressure reducing passage 15. To do. Therefore, even if the resin is supplied without defoaming in advance, bubbles generated from the resin are smoothly discharged out of the cavity 14.

  (2) The resin is injected into the cavity 14 at the first pressure until the resin gelation is started. After the resin injected into the cavity 14 starts to gel, the resin injection pressure is changed to the LRTM method. The second pressure higher than the injection pressure in is pressurized and injected. Therefore, even when the resin injection is almost impossible in the LRTM method, the resin is injected and the non-impregnated portion of the reinforcing fiber base 30 is easily impregnated with the resin, which is higher in Vf than in the LRTM method. A high-quality fiber-reinforced resin molded product can be manufactured.

  (3) The injection pressure is increased to the second injection pressure when a predetermined time elapses from the start of resin injection. Therefore, an appropriate time to increase the injection pressure from the first pressure to the second pressure is set simply by measuring the elapsed time from the start of injection without actually detecting the state of the resin in the cavity 14. be able to.

  (4) The second injection pressure is maintained for a preset time even after the gelation time necessary for the gelation of the resin injected into the cavity 14 has elapsed. Therefore, since the second injection pressure is maintained even after the completion of gelation, the resin is injected so as to compensate for the shrinkage when the amount of cure shrinkage is large until the resin is completely cured after the gelation is completed. Occurrence of pits (concave portions) and shrinkage on the surface of the fiber reinforced resin molded product is suppressed.

  (5) Resin injection at the first pressure is performed at a constant flow rate before the start of gelation. Therefore, as compared with the case of injecting the resin at a constant pressure, the resin is prevented from selectively flowing through the low-resistance portion of the reinforcing fiber base 30 and flows out of the cavity 14 from the deaeration member 18. As the amount decreases, the reinforcing fiber base 30 is easily impregnated with the resin uniformly.

  (6) A plurality of deaeration members 18 are provided, and each deaeration member 18 has the same distance from the injection port 19a of the injection hole 19 and is disposed symmetrically. Therefore, compared with the case where one deaeration member 18 is provided, or when the plurality of deaeration members 18 are arranged asymmetrically at different distances from the inlet 19a, the resin is reinforced fiber base 30. It becomes easy to impregnate uniformly.

The embodiment is not limited to the above, and may be embodied as follows, for example.
○ Instead of determining the time point of the start of gelation by the elapsed time from the start of the resin injection, the change of the state of the resin injected into the cavity 14 may be detected to estimate the gelation start time point. For example, the pressure of the resin injected into the cavity 14 is detected, and the gelation start time of the resin injected into the cavity 14 is estimated based on the pressure change. When gelation starts, the pressure required to inject the resin into the cavity 14 rapidly increases, so that the gelation start time can be estimated based on the pressure change of the resin. In this case, the accuracy is higher than in the case of estimating the gelation start time only by time.

  A sensor for detecting the dielectric constant of the resin in the cavity 14 may be provided in the mold 11 and the gelation start time and the progress of the gelation may be grasped based on the detection signal of the sensor. In this case, as compared with the case of estimating the gelation start time only by time, the accuracy of the gelation start time becomes higher, and the analogization of the gelation completion time and the progress of curing becomes simple.

  (Circle) injection | pouring of the resin in the 1st stage until gelatinization is started may be performed not with a fixed flow volume but with a fixed pressure. That is, instead of actively pumping out and injecting the resin, the resin may be injected into the cavity 14 by the differential pressure between the pressure in the resin tank (generally atmospheric pressure) and the pressure in the cavity 14. . However, it is preferable to inject at a constant flow rate. This is because when the injection is performed only with the differential pressure, the amount of the resin that selectively flows through the low-resistance channel and out of the cavity 14 increases. This is because impregnation is difficult.

  (Circle) you may stop injection | pouring of resin by 2nd pressure simultaneously with completion | finish of gelatinization. However, since the resin shrinks before the resin is completely cured even after the gelation is completed, it is preferable to hold the resin in a pressurized state with a pump even after the gelation is completed. In this case, since the resin is supplied into the cavity 14 as the resin contracts, the occurrence of shrinkage and pits (concave portions) is suppressed.

○ The pump for supplying the resin is not limited to the syringe pump, and other pumps such as a roller pump and a diaphragm pump may be used.
In the mold 11, the cavity 14 has a flat rectangular shape, one resin injection port 19a is provided at the center of the cavity 14, and deaeration members 18 (soft pinch-off cloths) are provided symmetrically at four locations. The configuration is not limited. Since the cavity 14 is formed in a shape corresponding to the shape of the reinforcing fiber substrate 30, if the shape of the reinforcing fiber substrate 30 is different from a substantially square plate shape, the shape of the cavity 14 is also changed accordingly. . The reinforcing fiber substrate 30 is not limited to a flat rectangular plate shape, and may be, for example, a plate shape having a bent portion or an arbitrary three-dimensional shape. Correspondingly, the number and arrangement position of the deaeration members 18 may be changed, or the position and number of the injection ports 19a may be changed.

(Circle) you may change the position of the discharge hole 20 according to the shape of the cavity 14, or you may make the number of the discharge holes 20 plural.
The deaeration member 18 is not limited to glass fiber or carbon fiber, and may be made of resin as long as it is a material that does not dissolve in the resin used.

O Even if it is the cavity 14 which arrange | positions the reinforced fiber base material 30 of fixed thickness, the shaping | molding die 11 may be provided not only in the structure provided horizontally but in an oblique shape.
○ Instead of providing both the injection hole 19 and the discharge hole 20 in the upper mold 13, either one may be provided in the lower mold 12, or both may be provided in the lower mold 12.

○ Instead of configuring the cavity 14 with only the lower mold 12, the upper mold 13 may also configure a part of the cavity 14.
The following technical idea (invention) can be understood from the embodiment.

  (1) In the first aspect of the invention, a sensor for measuring the dielectric constant of the resin in the cavity is provided, and the gelation is completed by grasping the progress of the gelation by the change in the dielectric constant of the resin in the cavity. A method for producing a fiber reinforced resin, in which the resin injection pressure is changed to a second injection pressure later.

  (2) In the invention according to any one of claims 1 to 3 and the technical idea (1), the resin injection at the first pressure is performed at a constant flow rate. Method.

(A) is a schematic plan view of the shaping | molding die in the state which abbreviate | omitted the upper mold | type, (b) is an expanded sectional view in the AA line of (a). The schematic block diagram of a manufacturing apparatus. The graph which shows the pressure change at the time of resin injection | pouring.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Molding die, 12 ... Lower die as 1st type | mold, 13 ... Upper die as 2nd type | mold, 14 ... Cavity, 15 ... Pressure-reduction channel | path, 18 ... Deaeration member, 19 ... Injection hole, 19a ... Inlet, 30: Reinforcing fiber substrate.

Claims (5)

A first mold in which a cavity is formed and a second mold that covers the cavity; a decompression passage is formed outside the cavity so as to surround the cavity; and the cavity and a part of the decompression passage In the state where the degassing member is disposed so as to straddle the mold, the inside of the cavity is decompressed through the decompression passage while the reinforcing fiber base is disposed in the mold that is closed, and the injection is communicated with the cavity. A method for producing a fiber-reinforced resin molded article comprising a resin impregnation step of injecting resin into the cavity from a hole and impregnating the reinforcing fiber base with resin,
The resin is injected into the cavity at a first pressure, and after the resin injected into the cavity starts to gel, the resin injection pressure is higher than the injection pressure in the LRTM (Light Resin Transfer Molding) method. 2. A method for producing a fiber-reinforced resin molded article, wherein the injection is carried out under a pressure of 2.   The method for producing a fiber-reinforced resin molded article according to claim 1, wherein the injection pressure is increased to the second injection pressure when a predetermined time elapses from the start of injection of the resin.   3. The fiber-reinforced resin molded article according to claim 1, wherein the second injection pressure is maintained for a preset time even after the gelation time required for gelation of the resin injected into the cavity has elapsed. Manufacturing method.   4. The pressure according to claim 1, wherein the second pressure is a pressure that allows air bubbles in the resin to pass through the degassing member after the resin starts gelling until the curing is completed. The manufacturing method of the fiber reinforced resin molded product of description.   The said deaeration member is provided with two or more, Each said deaeration member is equal to the distance from the injection hole of the said injection hole, and is arrange | positioned symmetrically. Manufacturing method of fiber reinforced resin molded article.

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