JP4371671B2 - Resin transfer molding method and sandwich laminate manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin transfer molding method using a resin fluid base material having a network three-dimensional structure and a method for producing a sandwich laminate.
[0002]
[Prior art and problems to be solved by the invention]
The resin transfer molding method is a kind of molding method using a thermosetting resin, and is a method of obtaining a molded product by injecting a resin into a mold cavity and curing it. The resin transfer molding method is used for manufacturing fiber reinforced plastics, sandwich laminates, and the like.
[0003]
A highly rigid mold is generally used as the mold for injecting the resin. However, for the purpose of manufacturing a large molded product, a part of the mold is replaced with a flexible bagging film. It has been broken.
[0004]
The fiber reinforced plastic molding using the resin transfer molding method is performed by laying a fiber reinforcing material on a mold, injecting resin into a cavity of the mold, and impregnating the resin into the fiber reinforcing material and curing it. Since the resin to be injected has high viscosity and the resin diffusion rate is slow, it takes a long time to inject the resin. For this reason, in resin transfer molding, a resin fluidized substrate has been used in order to improve the resin flow rate (Patent Document 1).
[0005]
The resin fluidized base material is a net-like knitted fabric or woven fabric having a thickness of about 0.2 to 5.0 mm, and is disposed so as to overlap the fiber reinforcement. At the time of molding, the resin flow base becomes a resin flow path, and the resin can be spread over the entire fiber reinforcing material in a short time.
[0006]
[Patent Document 1]
JP 2002-192535 A (page 3, paragraph number (0020))
[0007]
[Means for Solving the Problems]
As a result of intensive research, the present inventors have found that, in a resin transfer molding method using a resin fluidized base material, if a knitted fabric having a network three-dimensional structure is used instead of a conventional planar networked resin fluidized base material, more resin can be obtained. It has been found that a molded product that is easy to flow and has high quality can be obtained with a good yield, and that various manufacturing conditions can be easily controlled during molding, and the present invention has been completed.
[0008]
The present invention for solving the above problems is described below.
[0009]
[1] A fiber reinforcing material is laid on the lower mold, the bagging film or the upper mold is overlapped, and the periphery of the bagging film is hermetically sealed to the lower mold, or the upper mold and the lower mold are clamped, and then the bagging film or the upper mold In the resin transfer molding method in which the space between the mold and the lower mold is exhausted and the resin is injected into the fiber reinforcement.
(1) Between bagging film and fiber reinforcement and / or between lower mold and fiber reinforcement, or (2) Between upper mold and fiber reinforcement and / or between lower mold and fiber reinforcement. A resin transfer molding method comprising disposing a resin fluid base material having a net-like three-dimensional structure.
[0010]
[2] A fiber reinforcing material, a core material, and a fiber reinforcing material are sequentially stacked on one surface of the lower mold, and a bagging film or an upper mold is overlapped on these, and the periphery of the bagging film is hermetically sealed to the lower mold. In the method for producing a sandwich laminate, in which a mold and a lower mold are clamped, a bagging film or an upper mold and a lower mold are evacuated, and then a resin is injected and cured by a resin transfer molding method.
(1) Between bagging film and fiber reinforcement and / or between lower mold and fiber reinforcement, or (2) Between upper mold and fiber reinforcement and / or between lower mold and fiber reinforcement. A method for producing a sandwich laminate comprising disposing a resin fluid base material having a network three-dimensional structure.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The resin fluidized substrate used in the present invention is a knitted fabric having a network three-dimensional structure, and is different from a conventional planar mesh-shaped resin fluidized substrate in that it has stitches rising in a direction perpendicular to the knitted fabric. . Examples of such a knitted fabric include a three-dimensional structure knitted fabric having a hexagonal opening described in JP-A-2002-146657.
[0012]
Although the thickness of the resin fluidized substrate is appropriately determined depending on the viscosity of the resin to be injected, the use of the molded product, and the like, it is usually preferably 0.2 to 5.0 mm, more preferably 0.5 to 2.0 mm. The thickness of the resin fluidized substrate can be set to a desired value by changing the thickness and material of the yarn used for the resin fluidized substrate.
[0013]
Moreover, the opening width of the resin fluidized substrate is preferably 0.2 to 5.0 mm, and more preferably 0.5 to 2.0 mm.
[0014]
As the material of the yarn used for the resin fluidized base material, reinforcing fibers such as carbon fiber and aramid fiber can be used in addition to nylon and polyester which are usually used. A resin fluidized substrate using reinforcing fibers is extremely useful because it can increase the strength of the molded product when it is used as a part of the molded product without removing the resin fluidized substrate after molding.
[0015]
The thickness of the thread used for the resin fluidized substrate is preferably 1 to 200 dtex.
[0016]
The resin transfer molding method using a normal planar net-like resin fluidized substrate can produce a structure having a relatively simple shape, but it is difficult to produce a structure having a complicated shape. By using a resin fluid base material having a network three-dimensional structure, the followability of the resin fluid base material to the curved surface is increased, and it becomes easy to form a structure having a complicated shape that is difficult to form with a planar mesh fabric.
[0017]
Further, in the conventional resin transfer molding method using a planar net-like resin fluidized base material, a flow path of the resin must be secured with a flat knitted fabric, so that thick knitting is performed using a thick yarn of about 200 to 1000 dtex. It was necessary to use a woven fabric. In this case, the edge part of the resin fluidized base material cut according to the size of the molded product becomes sharp, the bagging film is damaged, and a void may enter the molded product. The resin fluid base material having a network three-dimensional structure used in the present invention has a sufficient thickness, and it is not necessary to use a thick thread. Therefore, even if the end portion of the resin fluidized substrate becomes sharp due to cutting, the bagging film is not damaged, and as a result, it contributes to improvement of molded article quality and product yield.
[0018]
Hereinafter, the resin transfer molding method of the present invention will be described with reference to FIG.
[0019]
First, the fiber reinforcing material 1 and the resin fluidized base material 2 are laid in order on a mold 3 which has been subjected to a release treatment using a known release agent such as silicone oil (FIG. 1A).
[0020]
A bagging film 7 is placed on the laid fiber reinforcing material 1 and the resin fluidized base material 2 and the periphery of the bagging film 7 is hermetically sealed with the mold 3 using a sealant 5. The material 2 is sealed. The sealant and the sealing method using the sealant are known.
[0021]
The material of the bagging film 7 is not particularly limited, and commonly used materials such as silicon, nylon, polypropylene, and polyimide can be used. Further, the shape of the bagging film 7 is not particularly limited, and can be appropriately selected and used depending on the shape of the mold and the target molded product. In the present invention, the bagging film includes a bag film, a rubber sheet, a rubber bag, and the like.
[0022]
After sealing the fiber reinforcement 1 and the resin fluidized substrate 2 using the bagging film 7, the gas between the mold 3 and the bagging film 7 is exhausted to reduce the pressure (FIG. 1 (b)), and formed on one end side of the mold. The resin is injected from the resin injection port. The injected resin moves through the resin fluidized substrate 2 toward the resin outlet formed on the other end of the mold and impregnates the entire fiber reinforcement 1.
[0023]
The resin injection is preferably performed while exhausting between the mold 3 and the bagging film 7 from the resin discharge port because the resin injection time can be shortened and the resin can be injected at a low injection pressure.
[0024]
In order to spread the resin more efficiently and impregnate the fiber reinforcing material, the gas between the mold 3 and the bagging film 7 is exhausted from the resin outlet and pressurized from the outside of the bagging film 7 toward the fiber reinforcing material 1 side. Also good. In this case, the pressurizing pressure is preferably 0.01 to 0.5 MPa.
[0025]
Then, the resin injected into the fiber reinforcing material is cured by heating the fiber reinforcing material 1 into which the resin is injected using an oven or the like together with the resin fluidized base material 2, the mold 3 and the bagging film 7 (FIG. 1C). ). The obtained molded product is a resin-impregnated layer 9 obtained by impregnating and curing the fiber reinforcing material 1 with a resin, a resin layer 10 in which a resin existing in the resin fluidized substrate is cured together with the resin fluidized substrate, and a resin covering the surface is cured. The surface resin layer 11.
[0026]
Even when the injected resin is cured, it is preferable to exhaust the gas between the mold 3 and the bagging film 7.
[0027]
In FIG. 1, the resin fluid base material 2 is disposed between the fiber reinforcement 1 and the bagging film 7, but the fiber reinforcement 1 and the mold instead of the resin fluid base material 2 or together with the resin fluid base material 2. Another resin fluid base material may be arranged between the two.
[0028]
Further, when the resin layer 10 is removed to reduce the weight of the molded product, a peel cloth or the like is inserted between the fiber reinforcing material 1 and the resin fluidized base material 2 for the purpose of improving the releasability of the resin layer 10. May be.
[0029]
As the fiber reinforcing material used in the resin transfer molding method of the present invention, materials used for ordinary fiber reinforcing materials such as carbon fiber, glass fiber, aramid fiber, boron fiber, and metal fiber can be used. Among these, carbon fiber, glass fiber, and aramid fiber are preferable.
[0030]
The form in particular of these fiber reinforcement materials is not restrict | limited, A woven fabric, a nonwoven fabric, etc. can be utilized.
[0031]
When weaving is used as the fiber reinforcing material, any woven type may be used, but the material itself is plane symmetric, or a plurality of fiber reinforcing materials are combined in a plane symmetric manner and stacked. It is preferable to use it. By using a plane symmetric fiber reinforcement or a piled and plane symmetric fiber reinforcement, it is possible to prevent warping of the molded product when formed into a molded product.
[0032]
Examples of the plane-symmetric fabric or the fabric that can be stacked to be plane-symmetric include a unidirectional fabric and a multiaxial fabric.
[0033]
The unidirectional woven fabric refers to a woven fabric in which bundles of fiber reinforcing materials arranged in parallel are knitted with nylon yarn, polyester yarn, glass fiber yarn or the like. A multiaxial woven fabric refers to a woven fabric in which bundles of fiber reinforcements (strands) aligned in one direction are formed in a sheet shape and laminated at different angles and knitted with nylon yarn, polyester yarn, glass fiber yarn, or the like.
[0034]
A schematic diagram of an example of a plane-symmetric multiaxial fabric is shown in FIG. In this example, the multiaxial fabric 100 is symmetrical with respect to the strand direction, that is, the direction in which the fibers are aligned, in order of 0 °, + 45 °, −45 °, + 45 °, and 0 ° with respect to the length direction of the multiaxial fabric. It has become. The multiaxial woven fabric 100 is formed by punching the five layers of fiber reinforcement laminated in this way in the thickness direction.
[0035]
Examples of other preferable multiaxial fabrics include [0 / -45 / -45 / 0], [0 / + 45 / -45 / -45 / + 45/0], [0 / + 45/90 / -45 /-. 45/90 / + 45/0]. For example, [0 / −45] and [−45/0], [0 / + 45 / −45] and [−45 / + 45/0], [0 / + 45 / −45 / 90] and [90 / −45 / + 45/0] can be exemplified. The angle at which the fiber reinforcements aligned in one direction are laminated is not limited to 0 °, ± 45 °, and 90 °, and can be any angle.
[0036]
The thickness of the multiaxial woven fabric is appropriately selected depending on the application of the molded product, but is usually preferably 0.2 to 3 mm.
[0037]
Basis weight of the fibrous reinforcement is preferably one per ^{200~4000g / m 2, 400~2000g / m} 2 is more preferable.
[0038]
As the resin used in the resin transfer molding method of the present invention, a thermosetting resin usually used for the production of a molded product can be used. Specifically, epoxy resin, unsaturated polyester resin, phenol resin, melamine resin, polyurethane resin, silicon resin, maleimide resin, vinyl ester resin, cyanate ester resin, resin obtained by prepolymerizing maleimide resin and cyanate ester resin, etc. In the present invention, a mixture of these resins can also be used. When using a fiber reinforced composite material, an epoxy resin composition and a vinyl ester composition excellent in heat resistance, elastic modulus, and chemical resistance are preferable. These thermosetting resins may contain a curing agent, a curing accelerator and the like.
[0039]
The thermosetting resin preferably has a viscosity at the time of resin injection of 0.01 to 1 Pa · s by heating or the like.
[0040]
Next, the manufacturing method of the sandwich laminate of the present invention will be described with reference to FIG.
[0041]
On the mold 3 subjected to the mold release treatment, a resin fluid base material 12 having a net-like three-dimensional structure, a fiber reinforcing material 13, a core material 14, a fiber reinforcing material 15, and a resin fluid base material 16 having a net-like three-dimensional structure are sequentially stacked. Thereafter, the laminated material is sealed with a bagging film, and a sandwich laminated board is manufactured by performing the same operation as the above-described resin transfer molding method.
[0042]
In addition, when making it a part of a sandwich laminated board without removing the resin fluid base material, the order of stacking the laminated materials is not limited to that shown in FIG. 2, and the resin can be supplied to the fiber reinforcing material. As long as stacking is performed, any order may be used.
[0043]
Examples of the core material include urethane foam, vinyl chloride foam, polymethacrylimide foam, acrylic foam, phenol foam, and polystyrene foam. Balsa wood can also be used.
[0044]
The thickness of the core material is appropriately selected depending on the use of the sandwich laminate, and is usually preferably 1 to 200 mm.
[0045]
Although FIGS. 1 and 2 show the case where a mold and a bagging film are used, in the present invention, a split mold having rigidity such as a metal mold and an FRP mold may be used. FIG. 4 shows an example of a cross-sectional view when resin transfer molding is performed using a split mold.
[0046]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0047]
Example 1
Multiaxial woven fabric (1) ([0 / + 45/90 / -45]) using carbon fiber HTA-12K (manufactured by Toho Tenax Co., Ltd.): CF basis weight 600 g / m ² was cut into a width of 1000 mm and a length of 1000 mm. . An aluminum plate with a plurality of rectangular grooves (width 20 mm, depth 30 mm, R2 mm) is released from the mold, and the multiaxial fabric (1) is at 0 ° layer on the bottom and the groove formation direction is 0 for the fabric. It was arranged on an aluminum plate so as to coincide with the ° direction. Multiaxial woven fabric (2) obtained in the same manner as the multiaxial woven fabric (1) ([−45 / 90 / + 45/0]: CF basis weight 600 g / m ² ) was cut into a width of 1000 mm and a length of 1000 mm and laminated. The multiaxial fabrics (1) and (2) were laminated on the multiaxial fabric (1) with the 0 ° layer facing upward so that the entire surface was symmetrical. Furthermore, a resin flowable substrate having a net-like three-dimensional structure on a multiaxial woven fabric (2) (three-dimensional structure having a hexagonal opening described in FIG. 2 of JP 2002-146657 A using a polyester thread having a thickness of 150 dtex) A knitted fabric with an opening width of 2 mm and a thickness of 3 mm) was laminated. Next, a sealant tape and a resin injection / discharge hose were placed on the aluminum plate, and the entire laminated material was covered with a bagging film (manufactured by Airtech) and sealed. After closing the mouth of the resin injection hose, the bagging film was evacuated with a vacuum pump from the resin discharge hose. Thereafter, 100 parts by mass of Lipoxy R-802, 1.0 part by mass of Permec N (manufactured by NOF Corporation), and 0.5 parts by mass of 6% cobalt naphthenate (manufactured by Kanto Chemical Co., Ltd.) were mixed at 25 ° C. It was poured into a bagging film from a resin injection hose under an atmosphere and cured to obtain a molded product. The mixed solution injected into the bagging film quickly spread over the entire multiaxial fabric through the resin flow base along the shape of the aluminum plate. The obtained molded product had almost no resin chipping, and the thickness of the product was uniform.
[0048]
Comparative Example 1
A molded product was obtained in the same manner as in Example 1 except that a planar net-like resin fluid base material (manufactured by Airtech Co., Ltd., trade name: Resin Flow 60) was used in place of the resin three-dimensional resin fluid base material.
The planar net-like resin fluidized base material stretched without following the shape of the aluminum plate, and the obtained molded product was resin-rich with a groove shape of about R5 mm, resulting in partial resin chipping.
[0049]
【The invention's effect】
Since the resin transfer molding method of the present invention uses a resin fluid base material having a network three-dimensional structure, a molded product with higher quality is produced as compared with a conventional molding method using a planar network resin fluid base material. be able to. Therefore, even a large molded product can be easily molded with a high yield. Furthermore, since the resin fluidized base material having a network three-dimensional structure has better shape followability than the planar networked resin fluidized base material, it is possible to manufacture a structure having a complicated shape.
[0050]
In addition, according to the method for manufacturing a sandwich laminate of the present invention, since the manufacturing time is short, it is not necessary to process a groove or a through-hole for flowing resin into the core material, so that sandwich lamination is performed at a low cost. A board can be manufactured.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an example of the molding method of the present invention, in which (a) is a cross-sectional view showing a state where a fiber reinforcing material and a resin fluidized base material are sealed between a bagging film and a mold; Is a cross-sectional view showing a state where the pressure between the bagging film and the mold is reduced, and (c) is a cross-sectional view showing a state in which a fiber reinforcing material is impregnated with a resin.
FIG. 2 is an explanatory view showing an example of a method for manufacturing a sandwich laminate of the present invention, and is a sectional view showing a state in which a laminate material is laid on one surface of a mold.
FIG. 3 is a schematic perspective view showing an example of a multiaxial fabric used in the present invention.
FIG. 4 is a cross-sectional view showing another example of the molding method of the present invention, using a split mold.
[Explanation of symbols]
1, 13, 15 Fiber reinforcing material 2, 12, 16 Resin fluid base material 3 Mold 3a Upper mold 3b Lower mold 5 Sealant 7 Bagging film 9 Resin impregnated layer 10 Resin layer 11 Surface resin layer 14 Core material 100 Multiaxial fabric

Claims (2)

After laying the fiber reinforcement on the lower mold, overlapping the bagging film or upper mold and sealing the periphery of the bagging film in an airtight manner or clamping the upper mold and lower mold, the bagging film or upper mold and lower mold In the resin transfer molding method in which the space between the two and the resin is injected into the fiber reinforcement,
(1) Between bagging film and fiber reinforcement and / or between lower mold and fiber reinforcement, or (2) Between upper mold and fiber reinforcement and / or between lower mold and fiber reinforcement. , A knitted fabric having a thickness of 0.2 to 5.0 mm having a stitch rising up perpendicularly to the plane of the knitted fabric formed of 1 to 200 dtex yarn, and the opening width in the direction perpendicular to the plane of the knitted fabric 0.2 to 2. Have a 0mm opening, resin transfer molding, characterized by placing the resin flow substrate reticulated three-dimensional structure having a hexagonal shaped opening in the plane of the knitted fabric. A fiber reinforcing material, a core material, and a fiber reinforcing material are sequentially stacked on one surface of the lower mold, and a bagging film or an upper mold is overlaid on these, and the periphery of the bagging film is hermetically sealed to the lower mold, or the upper mold and the lower mold. In the sandwich laminate manufacturing method in which the mold is clamped and the bagging film or between the upper mold and the lower mold is exhausted, and then the resin is injected and cured by a resin transfer molding method.
(1) Between bagging film and fiber reinforcement and / or between lower mold and fiber reinforcement, or (2) Between upper mold and fiber reinforcement and / or between lower mold and fiber reinforcement. , A knitted fabric having a thickness of 0.2 to 5.0 mm having a stitch rising up perpendicularly to the plane of the knitted fabric formed of 1 to 200 dtex yarn, and the opening width in the direction perpendicular to the plane of the knitted fabric 0.2 to 2. It has a 0mm openings method for manufacturing a sandwich laminate, which comprises placing the resin flow substrate reticulated three-dimensional structure having a hexagonal shaped opening in the plane of the knitted fabric.

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