JP2005193587A - Resin transfer molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin transfer molding (RTM) method which can easily and stably mold an FRP molding having excellent surface designability by suppressing the occurrence of bubbles in the surface which is hardly achieved in the conventional FRP molding method and excellent mechanical properties and quality by suppressing the occurrence of voids between layers of a reinforcing fiber substrate. <P>SOLUTION: In the RTM method of a fiber-reinforced resin member, the reinforcing fiber substrate which is made into a preform is arranged in the cavity of a mold, the substrate is impregnated with a reactive resin by injecting the resin from a resin injection port while the resin is pressurized, and the resin is heated and cured. The injection velocity of the reactive resin into the cavity is controlled to adjust the ratio (Q/S: cc/min×m<SP>2</SP>) between the flow rate of the resin per unit time (Q: cc/min) and the projected area of the cavity (S: m<SP>2</SP>) to be 60<Q/S<550. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the resin transfer molding method (hereinafter referred to as RTM molding method) used for molding a fiber reinforced plastic (FRP) member, the present invention provides an FRP having a good surface design by providing optimum molding conditions. The present invention relates to an improvement in an RTM molding method for molding a member in a short time with high efficiency.

  Conventionally, for the purpose of weight reduction, an RTM molding method for FRP automobile members using continuous reinforcing fibers has been actively researched and developed.

  By the way, the mold used for the above RTM molding method includes a vertical crack mold and a horizontal crack mold, but the vertical crack mold (which is often found in injection molds) tends to make the resin flow constant due to the influence of gravity. Since the bubbles inside are easy to rise and escape, there is a merit that there are very few voids and pits that cause problems in the surface quality of the molded product, but on the other hand, a set of reinforcing fiber base in the mold, that is, There is a big problem that productivity is low because it is difficult to dispose the base material on the cavity surface of the mold and to fix it to the mold surface, and it takes a lot of time. On the other hand, when the transverse cracking mold, that is, the upper and lower molds are configured, the above-mentioned reinforcing fiber base can be set on the mold surface relatively easily and has a merit that the setting time can be shortened. Injection method, that is, pressurizing at a pressure of 0.2 to 1.0 MPa, and injecting the resin without controlling the special flow rate, the resin flows into the mold at a flow rate corresponding to the pressure, and it takes a relatively short time. In this case, the resin is filled in the mold, but the reinforcing fiber base material is disturbed by the resin flow, or the flow velocity is high and the non-uniform flow occurs, so that many voids and pits are generated on the surface of the molded product.

  Under such circumstances, in the prior art, in order to uniformly inject the resin into the cavity in a voidless state, a resin diffusion medium is disposed at least partially in the cavity, and the partial resin in the cavity A technique for eliminating the flow failure and impregnation failure has been proposed (for example, Patent Document 1), but it is not sufficient because the flow conditions of the resin are not taken into consideration. In particular, if it is necessary to inject the resin at a high pressure of 0.5 MPa or higher (and hence at a high speed) in order to shorten the molding time or to mold a large-area molded product in a short time, Uniform because the weave structure of the material (especially plain woven fabric) is likely to be disturbed, and the resin flows through the mold at high speed, so the flow resistance varies within the flow region due to subtle thickness irregularities and differences in the composition of the base material. A large flow cannot be maintained, and a large void may occur due to partial “flow ahead”. Furthermore, although the resin flows into the base material portion in practice, the flow is so fast that, for example, the gas suitable for the weaving of the fabric stays without any escape and causes defects on the surface as pits. There is a case to let you. With conventional molding conditions and molding processes that cause a decrease in appearance quality related to such design properties, high surface quality cannot be ensured while performing high-speed injection for shortening the molding time. As the size of the molded product increases, such high-speed resin injection is inevitably caused, so that such defects in appearance quality tend to occur.

  Since the flow state of the resin greatly affects the generation of voids and pits related to such design properties, the density of the reinforcing fiber base material, that is, the basis weight, is also an important factor. That is, since the basis weight of the reinforcing fibers per layer affects the flow resistance of the resin and the ease of bubble removal, it is necessary to set an appropriate basis weight according to the resin flow conditions. In order to optimize the basis weight, it is necessary to set not only the surface quality but also the viewpoint of the workability of the preform, the strength utilization rate, and the like. That is, if the basis weight is too large and the rigidity of the base material becomes high, it is difficult for the reinforcing fiber base material to follow the mold surface, making it difficult to form a three-dimensional shape, and it takes a lot of work time to form a preform. There may be a situation in which the mechanical properties of the FRP molded product deteriorate due to material disturbance. That is, in order to carry out efficient production, there is a basis weight suitable for production conditions (molding size, molding conditions, etc.).

  Further, among the molding conditions, the influence of the temperature and the resin injection pressure on the surface quality is particularly great. When the resin temperature to be injected is high, the viscosity decreases and the fluidity increases, and the resin impregnation property to the base material is good, but the viscosity increase rate increases and the fluidity suddenly deteriorates. The flow may slow down from the middle, resulting in unimpregnation. Even if the resin flows somewhere in the whole area, voids and pits may frequently occur in the region where the viscosity is high even if the resin is not impregnated. On the other hand, if the mold temperature is uneven or changes during molding, minute bubbles remaining in the mold may come into contact with each other and grow into large bubbles that develop into voids or pits.

  Also, the pressure needs to be moderate. In some cases, it is too high and causes volume expansion in the cavity to generate bubbles, or it is too low to compress the remaining bubbles to be small.

  Also, reactive gas is generated from the reactive resin during the curing process, or fine gas (bubbles) already contained in the resin grows with time and grows into voids and pits. It is better to cure as soon as possible after impregnating the substrate.

  The influence of the material properties of the reactive resin on the molding efficiency is very high. For example, depending on the type of curing agent, the reaction rate becomes maximum at the beginning of the reaction of the resin, and the reaction rate decreases with time. Therefore, the time required for curing may become long. On the other hand, when trying to shorten the curing time by increasing the temperature of the mold, the initial increase in viscosity becomes excessive, the viscosity increases excessively during resin injection and flow, and eventually gels. There is a case where the molding stops in the middle and an unimpregnated portion is generated.

As described above, FRP molding (particularly, RTM molding method) has molding conditions and material characteristics corresponding to the molding size (area). If molding is not performed under appropriate conditions, there is a problem in terms of quality, particularly surface quality. It can be said that it is easy to occur.
JP 2002-192535 A

  The present invention eliminates the above-mentioned problems of the prior art, and in an RTM molding method using a horizontal split mold (upper and lower molds) that can be easily placed in a mold of a reinforcing fiber base and can be set in a short time. An object of the present invention is to provide an RTM molding method capable of efficiently molding (manufacturing) a molded article having a high surface design with few voids and pits.

In order to solve the above-mentioned problems, the present invention arranges a preformed reinforcing fiber base in a cavity of a mold, and injects a reactive resin from a resin injection port while pressurizing the reinforcing fiber base. In the RTM molding method of the fiber reinforced resin member that is heat-cured after impregnating the material with resin, the injection rate of the reactive resin into the cavity is defined as a unit time flow rate (Q: CC / min) of the reactive resin. The ratio (Q / S: CC / min · m ² ) to the projected area (S: m ² ) of the cavity is
60 <Q / S <550
The RTM molding method is characterized by injecting within the range.

In this case, it is preferable to inject the resin while pressurizing the reactive resin in a state where the inside of the cavity is decompressed. Further, the ratio (Q / S: CC / min · m ² ) between the unit flow rate (Q: CC / min) of the reactive resin and the projected area (S: m ² ) of the cavity, and the reactive resin The product ((Q / S) × P: CC · MPa / min · m ² ) with the applied pressure (P: MPa) of
20 ≦ (Q / S) × P ≦ 400
It is preferable to inject the resin under the conditions within the above range. And it is preferable to make the pressurizing force of reactive resin into the range of 0.2-0.8 MPa, and it is more preferable to make it fluctuate with time. The heating temperature is preferably injected at a constant temperature in the range of 60 to 160 ° C. and cured within a range of 3 to 30 minutes.

The constituent fiber of the reinforcing fiber base used in the method of the present invention is preferably a carbon fiber having a basis weight of 150 to 500 g / m ² , and the resin is preferably an epoxy resin containing alcohol as a curing component. . The obtained fiber reinforced resin member has a thickness of 1 mm or more. The obtained molded product can be mainly used for a design member of an automobile.

  According to the RTM molding method of the present invention, a molded product in which defects such as voids and pits are not generated on a surface which is a design surface, which has been difficult under conventional RTM molding conditions, is efficiently and stably molded in a short time. I can do it. Therefore, a molded product having a good surface quality can be mass-produced at a high cycle.

  Hereinafter, the best embodiment of the RTM molding method of the present invention will be described.

The FRP member obtained by carrying out the RTM molding method of the present invention refers to a resin reinforced with reinforcing fibers. Examples of the reinforcing fibers include carbon fibers, glass fibers, alumina fibers, metal fibers, and silicon nitride fibers. Inorganic fiber such as polyamide synthetic fiber, polyolefin synthetic fiber, polyester synthetic fiber, polyphenylsulfone synthetic fiber, polybenzoxazine synthetic fiber, acetate, acrylonitrile synthetic fiber, modacrylic fiber, polyvinyl chloride synthetic fiber Organic fibers such as fibers, polyvinylidene chloride synthetic fibers, polyvinyl alcohol synthetic fibers, polyurethane fibers, polyclar fibers, protein-acrylonitrile copolymer fibers, fluorine fibers, polyglycolic acid fibers, phenol fibers, para-aramid fibers, etc. A single species, Rui can choose multiple species. These reinforcing fibers can take various forms such as a woven fabric, a nonwoven fabric, a mat, and a short fiber. Among them, as fibers suitable for design members such as automobile outer plates, carbon fibers and glass fibers having high strength and high rigidity can be mentioned.
The reinforcing fiber substrate used in the present invention refers to a reinforcing fiber that is not impregnated with a resin, for example, and its form is a short fiber-like homogeneous form such as a nonwoven fabric, mat, knit material, chop degree fiber, etc. preferable. Furthermore, the combination of these and insert parts etc. are mentioned, and it uses properly by the use. Examples of the insert parts include metal plates such as steel and aluminum, metals for joining such as metal columns, metal bolts, nuts, and hinges, aluminum honeycomb cores, polyurethane, polystyrene, polyimide, vinyl chloride, phenol, acrylic, and the like. Foam materials, rubber materials, wood materials, etc. made of high polymer materials are mainly used for inserts aimed at joining nails and screws etc. Insert parts that are used for the purpose of damping during vibration are often used.

  Furthermore, the reinforcing fiber of the present invention includes a case where a part of the fiber is already impregnated with the resin described below (state called prepreg, semi-preg, partially impregnated prepreg, etc.).

  As the resin used in the RTM molding method of the present invention, a thermosetting resin having a low viscosity and easily impregnating reinforcing fibers or a monomer for RIM (Resin Injection Molding) that forms a thermoplastic resin is suitable. Examples of thermosetting resins include epoxy resins, unsaturated polyester resins, polyvinyl ester resins, phenol resins, guanamine resins, polyimide resins such as bismaleide triazine resins, furan resins, polyurethane resins, polydiallyl phthalate resins, A melanin resin, a urea resin, an amino resin, etc. are mentioned.

  Further, polyamides such as nylon 6, nylon 66 and nylon 11, or copolymer polyamides of these polyamides, polyesters such as polyethylene terephthalate and polybutylene terephthalate, or copolymer polyesters of these polyesters, polycarbonate, polyamideimide, Polyphenylene sulfide, polyphenylene oxide, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polyolefin, and the like, and thermoplastic elastomers typified by polyester elastomers, polyamide elastomers, and the like are also included.

  Also, a resin obtained by blending a plurality selected from the above-mentioned thermosetting resins, thermoplastic resins, and rubbers can be used. Among them, an epoxy resin is preferable as a preferable resin from the viewpoint of suppressing thermal shrinkage at the time of molding that affects the design of the automotive outer plate member.

  Generally, as an epoxy resin for composite materials, a bisphenol A type epoxy resin, a phenol novolac type epoxy resin, or a glycidylamine type epoxy resin is used as a main agent. On the other hand, as a curing agent, a curing agent system in which dichlorophenyldimethylurea is combined with dicyandiamide is preferably used in terms of excellent workability and physical properties. However, it is not particularly limited, and diaminodiphenyl sulfone, aromatic diamine, acid anhydride polyamide and the like can also be used. Further, the ratio of the resin and the above-mentioned reinforcing fiber is preferably in the range of 20:80 to 70:30 in terms of the weight ratio in order to maintain appropriate rigidity as the outer plate. Among them, modified epoxy resin, nylon resin, dicyclopentadiene resin blended with epoxy resin or thermoplastic resin, rubber component, etc. are more suitable from the viewpoint of reducing thermal shrinkage of FRP structure and suppressing generation of cracks. .

  Next, the best mode for carrying out the invention will be described with reference to the drawings.

  FIG. 1 is an overall schematic view of a molding facility for carrying out the RTM molding method of the present invention. The molding die 2 includes an upper die and a lower die, and is attached to the die lifting device 1. Place the reinforcing fiber base directly on the lower mold, or the preform base formed into the product shape in advance so that the reinforcing fiber base is easy to fit in the mold, and close the upper mold. Examples of the material of the mold include FRP, cast steel, structural carbon steel, aluminum alloy, zinc alloy, nickel electroforming, and copper electroforming. For mass production, structural carbon steel is suitable in terms of rigidity, heat resistance, and workability.

  The molding die was arbitrarily provided with a resin injection channel 13 connected to a plurality of resin injection ports 8a and a discharge channel 14 connected to the discharge ports 8b. The resin injection channel 13 and the discharge channel 14 are respectively connected to the injection port 8a and the discharge port 8b via a coupler. A resin injection device 3 is connected to the resin injection flow path 13. The resin injecting device 3 stores a main agent and a curing agent in a main agent tank 5 and a curing agent tank 6, respectively, and each tank has a mechanism capable of heating and vacuum degassing. At the time of resin injection, the resin is pushed from the respective tanks toward the resin injection flow path 13 by the pressurizing device 12. The pressurizing device 12 uses syringe pumps 12a and 12b, and it is preferable for a resin that is cured by two-liquid mixing to ensure quantitativeness by simultaneously extruding the syringes. It is mixed by the mixing unit 4 and reaches the resin injection channel 13. The discharge path 14 is connected to a resin trap 15 in order to prevent the resin from flowing into the vacuum pump 7a or the pressure pump 7b.

  The number and position of the injection ports 8a vary depending on the shape and size of the molding die, the number of molded products that are simultaneously molded in the mold, and the like, but it is preferable that the number of injection ports 8a be as small as possible. This is to prevent the injection work from becoming complicated due to an increase in the number of locations where the injection flow path 13 from the resin injection device 3 is connected to the injection port 8a.

  The material of the resin injection flow path 13 needs to ensure sufficient flow rate and compatibility with the resin (temperature, solvent resistance, pressure resistance). A tube with a diameter of 5 to 30 mm is used. A pressure resistance of 1.0 MPa or more is required to withstand the injection pressure of the resin, and a heat resistance of 100 ° C. or more is required to withstand the temperature during resin curing, and the thickness is 2 mm. A tube made to the extent of “Teflon” is preferred. However, in addition to “Teflon”, a relatively inexpensive polyethylene tube, or a metal tube such as steel or aluminum may be used.

  Further, the number and positions of the discharge ports 8b vary depending on the shape and size of the molding die, the number of molded products that are simultaneously molded in the mold, and the like, but it is preferable that the number of discharge ports be as small as possible.

  Furthermore, it is preferable that the discharge port 8b is installed at a high position in a direction in which the gas is more likely to float than the injection port 8a so that the gas remaining in the mold can be easily released.

  As for the material of the discharge path 14, it is necessary to take into consideration the securing of a sufficient flow rate and compatibility with the resin (temperature, solvent resistance, pressure resistance), as with the supply path 13. The discharge path 14 may be a metal tube such as steel or aluminum, or a plastic tube such as polyethylene or “Teflon”, but a “Teflon” tube having a diameter of 5 to 10 mm and a thickness of 1 to 2 mm is easy to work with. Is more preferable.

  The injection valve 21 and the discharge valve 22 installed in the middle of the resin injection flow path 13 and the discharge path 14 at the time of resin injection can be opened / closed and the diameter of the entire area can be changed by directly sandwiching the flow path by a worker with a vise grip or the like. Can do. In addition, it is possible to apply a valve opening / closing device that is automated by installing an actuator in the handle portion of the vice grip, or using an electromagnetic valve or an air operation valve instead of the vise grip. It is also preferable to perform more accurate opening / closing by connecting the valve opening / closing device to a storage device in which valve opening information is input in advance. Further, the discharge valve 22 can change the diameter of the flow path (adjustment of the opening degree of the ball valve) instead of simply opening and closing binary values.

  The pressurization of the resin can also provide quantitativeness by a pressurizing method using a syringe pump or the like. The resin injection pressure is preferably in the range of 0.1 to 1.0 MPa. Here, the injection pressure of the resin refers to the maximum pressure pressurized by the pressurizing device 12, and represents the pressure displayed by the injection pressure gauge 31 of FIG.

  When the resin in the mold is finally completely impregnated into the mold and reaches the discharge path 14, the discharge path 14 is closed, and after that, the inside of the mold is held for a while with the injection pressure, and then the injection flow path is also closed to complete the resin injection. To do. The mold is heated by a hot water circulation type temperature controller 26, thereby curing the resin. The in-mold resin pressure represents the pressure of the in-mold pressure gauge 32.

In order to stably obtain a high-quality FRP molded product having excellent appearance quality and predetermined mechanical properties by performing RTM molding with the RTM molding equipment (molding system) as described above,
In addition to optimizing advance preparations such as cutting, laminating, preforming, and laying up the mold, the molding conditions from resin injection, impregnation, and curing are very important. It is necessary to set production conditions appropriately considering efficiency.

  To that end, the “resin injection pressure”, “molding temperature”, “resin flow rate”, “resin temperature characteristics”, etc., which have already been pointed out, are carefully considered after considering the characteristics of the reactive resin. It is necessary to set an appropriate value corresponding to the dimension. In particular, in this patent, fluidity is good considering production efficiency, but on the other hand, it is intended for a reactive resin material that gels in a short time and hardens immediately, so high-speed fluid impregnation is required.

  However, when the resin pressure is increased and the flow rate is increased, the substrate is easily disturbed and voids and pits are likely to be generated on the surface layer as described above. Accordingly, simply increasing the flow rate causes problems in the appearance quality as described above, and therefore it is necessary to set an appropriate resin flow rate for the substrate to be impregnated, that is, a flow rate corresponding to the area of the substrate.

Accordingly, in the examples described later, the appearance quality (surface quality of the design surface) was evaluated by varying the resin injection flow rate with respect to the dimension (area) of the automobile outer plate member that is the actual molding target member. That is, six types of RTM molds of 0.4 to 2.4 m ² were used, and prototype molding was performed by changing the injection (discharge) speed by changing the injection pressure of the resin.

The substrate used was a 4ply laminate of carbon fiber “Torayca” cloth (CK6243C: T700-12K, basis weight: 300 g / m ² , area: 1.0 m ² / ply) manufactured by Toray Industries, Inc. and heated to about 110 ° C. After being placed in the flat plate molding die and sealing the die, vacuum suction was performed from one side while injecting a reactive epoxy resin having a pressure of 0.5 MPa from one side. After the resin has flowed and impregnated throughout the vacuum, the vacuum suction is stopped, the pressure is maintained at the resin injection pressure for several tens of seconds, and then the resin is heated and cured for a predetermined time (about 10 minutes) to remove the molded product from the mold, A CFRP flat plate having a thickness of about 1.4 mm was obtained.

  Table 1 below shows the results of evaluating the appearance of the molded product.

The numerical value in the lower part of the frame in the table is the ratio (Q / S) between the flow rate of the injected resin (Q: CC / min) and the projected area (S: m ² ) of the molded product.
Is the value of Evaluation results are shown in the following categories.

    ◯: There are no defects in appearance, and the design is extremely excellent.

     ○: There is no problem in appearance, and the design level that enables commercialization.

     △: Slight voids and pits are seen on the surface, but it can be commercialized when polished.

     X: The level and quantity of surface voids and pits are difficult to repair.

  Note that the reactive resin used in the evaluation prototype is a highly fluid and fast-curing epoxy having a viscosity-time characteristic as shown in FIG. 2, which is an object of application of the present invention to increase production efficiency. Resin. Specifically, the main epoxy resin is “Epitoto” YD128 “diglycidyl ether of bisphenol A” manufactured by Toto Kasei Co., Ltd., “2-methylimidazole” of tertiary amine, “glycerin” of alcohols and “1, This is a mixed component of “2-ethanediol”.

  That is, it is a fast curing resin that gels in about 8 minutes after the start of resin flow and cures to a demoldable level in an environment of 100 ° C.

As can be seen from Table 1, “Q to XX”, which is a level that can be commercialized, has the above Q / S value.
60 <Q / S <550
It can be said that it is within the range.

  Furthermore, Table 2 shows the result of multiplying the Q / S value, which is a factor for evaluating the surface quality, by the discharge pressure P under the conditions shown in Table 1.

As can be seen from Table 2, “Q to XX”, which is a level that can be commercialized, has a value of (Q / S) × P described above.
20 <(Q / S) × P <400
Within the range of is preferable.

  Next, an embodiment of the present invention will be described with reference to the aforementioned drawings.

An overall view of an RTM molding apparatus implemented as an example of molding under the RTM molding conditions according to the present invention is shown in FIG. 1, and viscosity-time characteristics at the molding temperature of the resin used for molding are shown in FIG. Carbon fiber “Trekka” cloth (CO7373B) manufactured by Toray Industries, Inc. on metal mold 2 (both upper and lower molds: length 2000 mm, width 1800 mm, height 500 mm) each having one inlet 8a and one outlet 8b. : T300B-3K, basis weight: 192 g / m ² , area: 2.1 m ² / ply) 6ply laminated (0/90 °; 3ply, ± 45 °; 3ply) and preformed into the shape of the hood of a car in advance The mold was placed on the cavity surface of the lower mold, and the upper mold was closed and completely sealed by the mold elevator 1. The upper mold is pressurized by the mold elevator 1 at 2 MPa. Both the upper mold and the lower mold are heated to 100 ° C. by the temperature controller 26.

  A resin injection flow path 13 was connected to the injection port 8a, and a discharge path 14 was connected to the discharge port 8b. A tube made of “Teflon” having a diameter of 16 mm and a thickness of 2 mm was used for both the injection channel 13 and the discharge channel 14. In order to prevent the resin from flowing into the discharge path 14 to the vacuum pump 7a, a resin trap 15 is provided on the way.

  In order to keep the inside of the mold sealed, a sealing material (O-ring) is arranged on the outer periphery of the cavity surface. Ideally, the upper mold is closed so that the interior of the mold does not communicate with any place other than the resin injection channel 13 and the discharge channel 14. However, substantially complete sealing is difficult. For example, the pressure of a vacuum pressure gauge (not shown) is monitored with the injection valve 21 disposed in the resin injection path 13 closed and the discharge valve 22 opened. Here, the sealed state was confirmed that there was no problem in molding as long as 0.01 MPa was maintained for 10 seconds after the vacuum pump 7a was stopped.

  After discharging from the discharge port 8b with the vacuum pump 7a and confirming that the in-mold pressure has become 0.01 MPa or less by the vacuum pressure gauge, the pressurizing device 12 starts injecting resin. The pressurizing device 12 uses syringe pumps 12a and 12b, and is configured to prevent the backflow of the resin to the tank side when the resin is injected. As the main resin, Epicoat 828 (manufactured by Yuka Shell Epoxy Co., Ltd., epoxy resin) was used as the main agent, and as the curing agent, a liquid epoxy resin obtained by mixing TR-C35H (imidazole derivative) of Toray Blend was used. FIG. 2 shows the viscosity-time characteristics of this epoxy resin at a molding temperature of 100 ° C., specifically, the cure index value in which the viscosity change of the epoxy resin composition is used as an index for tracking the curing profile of the resin. According to the graph, the glass transition point (Tg) exceeds 100 ° C. in about 8 minutes, and the resin can be demolded.

  In the resin injection device 3, the main agent 5 and the curing agent 6 were heated in advance at 40 ° C. while being stirred, lowered to a predetermined viscosity, and defoamed by the vacuum pump 7.

At the initial stage of resin injection, the air in the resin mixing unit 4 and the air in the hose entered, so that they were discarded from a branch path (not shown) without flowing into the mold. The discharge conditions of the syringe pumps 12a and 12b of the pressurizing apparatus were set to 200 CC / stroke. When the injection resin pressure during discharge is set to 0.6 MPa, the ratio (Q / S) between the resin injection flow rate (Q: CC / min) and the projected area of the cavity (S: m ² ) is about 200 (CC / Min · m ² ). After the first resin is discarded, the injection resin pressure (0.6 MPa) is confirmed by an injection pressure gauge 31 installed in the injection flow path 13, the injection valve 21 is opened, and the resin is injected into the mold. At the start of injection, the discharge path 14 was open. Using the vise grip, the impregnation of the reinforced fiber base material with resin and the opening and closing of the discharge valve 22 were performed three times as operations for efficiently removing bubbles.

  After completion of the resin injection impregnation, the discharge valve 22 was closed, and after that, the pressure was maintained at a resin pressure of 0.6 MPa for 30 seconds, and after heating and holding for 12 minutes, the molded product was taken out from the mold.

The appearance of the entire area of the molded article having the shape of a bonnet hood of about 2 m ² was evaluated, but it was a good product with no voids or pits and very rich in design.

  The RTM molding method of the present invention can be suitably used mainly in the manufacturing field of design members including panel members as outer plate members for automobiles. Here, the automobile outer plate member is a so-called panel member such as a door panel, a hood, a roof, a trunk lid, a fender, a spoiler, a side skirt, a front skirt, a mud guard, and a door inner panel in an automobile or a truck, and other related panels. Examples of members include panels such as doors, side panels, interior panels, and cranes in railway vehicles. However, the present invention is not limited to these, it is on the outside of construction machinery covers other than the automobile field, partition plates in construction, party shavers, door panels, shielding plates, surfboards in sports, skateboards, bicycle parts, etc. The present invention can also be applied to the field of manufacturing members that require design properties.

It is a general | schematic general view of the shaping | molding apparatus for enforcing the RTM shaping | molding method of this invention. It is a characteristic view of the reactive resin used for the trial manufacture for evaluation in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold raising / lowering device 2 Molding die 3 Resin injection device 4 Mixing unit 5 Main agent tank 6 Hardener tank 7a Vacuum pump 7b Pressure pump 8a Inlet 8b Discharge port 9 Hydraulic unit 10 Hydraulic pump 11 Hydraulic cylinder 12 Pressurizing device ( Syringe pump)
DESCRIPTION OF SYMBOLS 13 Resin injection flow path 14 Discharge path 15 Resin trap 20 Reinforcement fiber base material 21 Injection valve 22 Discharge valve 24 Vacuum pump 26 Mold temperature controller 31 Injection pressure gauge 32 In-mold pressure gauge

Claims (10)

Fiber reinforced by placing a preformed reinforcing fiber base in the cavity of the mold, injecting the reactive resin from the resin injection port while applying pressure, impregnating the reinforcing fiber base with resin, and then heat-curing the resin. In the RTM molding method of the resin member, the injection rate of the reactive resin into the cavity is determined by changing the flow rate of the reactive resin per unit time (Q: CC / min) and the projected area of the cavity (S: m ² ). (Q / S: CC / min · m ² )
60 <Q / S <550
An RTM molding method characterized by injecting within the range.    2. The RTM molding method according to claim 1, wherein the resin is injected while pressurizing the reactive resin in a state where the inside of the cavity is decompressed. The ratio (Q / S: CC / min · m ² ) between the unit flow rate (Q: CC / min) of the reactive resin and the projected area (S: m ² ) of the cavity, and the addition of the reactive resin The product ((Q / S) × P: CC · MPa / min · m ² ) with the pressure (P: MPa)
20 ≦ (Q / S) × P ≦ 400
The RTM molding method according to claim 1 or 2, wherein the resin is injected under a condition within the range.   The RTM molding method according to any one of claims 1 to 3, wherein the pressure of the reactive resin is within a range of 0.2 to 0.8 MPa.   The RTM molding method according to claim 1, wherein the reactive resin is cured at a constant temperature in the range of 60 to 160 ° C. and in the range of 3 to 30 minutes. . Fibers, RTM molding method according to claim 1 having a basis weight which comprises using the carbon fiber in the range of 150~500g / m ² constituting the reinforcing fiber substrate.   The RTM molding method according to claim 1, wherein the reactive resin is an epoxy resin containing alcohol as a curing component.   The RTM molding method according to claim 1, wherein the pressure of the reactive resin is changed with time.   The thickness of the obtained fiber reinforced resin member is 1 mm or more, The RTM shaping | molding method in any one of Claims 1-8 characterized by the above-mentioned.   9. The RTM molding method according to claim 1, wherein the obtained fiber reinforced resin member is an automobile design member.

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