JP2013035194A - Rtm molding method and frp molding thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable with a high degree of accuracy, molding of a resin molded product even if having a complex shape part without accompanying decrease in productivity though using the phenol resin for the matrix resin.SOLUTION: In an RTM molding method to obtain an FRP molding by disposing a placing piece 5 to a predetermined position, while laying down a reinforced fiber sheet 60 by providing a gel coat coating layer 50 to a lower mold 2, sticking the overlapped parts of the outer peripheral side of upper and lower both molds, covering with the upper type 3 afterwards, and after injecting and impregnating the thermosetting resin into the reinforced fiber sheet 60 and filling it in the mold inside 20, and curing the thermosetting resin by heating at prescribed temperature, the thermosetting resin is used for the phenol resin, and the placing piece 5 prepared by combining the soft resin piece 5a and the hard resin piece 5b is disposed to fill the gap space 25 having the under part 25a in the mold inside 20.

Description

  The present invention relates to an RTM molding method and an FRP molded product thereby, and more particularly to an RTM molding method using a phenol resin as a matrix resin, and a lightweight and flame-retardant FRP molded product produced thereby.

  In the field of space and aircraft parts, products with excellent heat resistance and flame resistance are required from the viewpoint of ensuring safety. Polyester resins and vinyl ester resins are also hydroxylated in resin molded products used for interiors, etc. In general, a flame retardant such as aluminum is mixed to improve heat resistance and flame retardancy.

  When a resin mixed with such a flame retardant is used for RTM (Resin Transfer Molding) molding, the resin has a high viscosity and it is difficult to impregnate the reinforcing fiber, resulting in voids and the like, which tends to reduce the accuracy of the molded product. There is a problem. For this reason, hand lay-up (hand-lamination) molding is usually employed for the flame-retardant resin, but this molding method requires a lot of labor and tends to make it difficult to ensure productivity. In addition, it has been pointed out that there is a demerit that the specific gravity is increased by mixing a flame retardant in an aircraft part that is particularly light.

  On the other hand, phenol resin is well known as a thermosetting resin having a relatively small specific gravity and excellent mechanical strength, heat resistance and flame retardancy. When this is used as a matrix resin for RTM molding, the viscosity is lower than that of the resin mixed with the above-mentioned flame retardant, but depending on the shape of the molded product, an insufficiently impregnated part is likely to occur, and an under part is included. It is difficult to mold a component having a complicated shape with high accuracy with little effort.

  In contrast, JP-A-2001-260238 discloses that a groove is provided on the surface of the core material and the resin is diffused through the groove by injecting a phenol resin from one side of the core material. A method has been proposed in which a through-hole penetrating from the surface to the opposite side is provided, and through this, the resin is diffused to the opposite side of the core material. Even when a phenol resin is used as the matrix resin, an insufficiently impregnated part occurs. It is known as an RTM molding method that makes it easier to avoid this.

  However, this molding method cannot be applied to a molded product without a core material, and in addition, there is a problem that it is still difficult to create a complicated shape including an under part with high accuracy and with little effort. . On the other hand, in recent years, phenol resins with relatively low viscosity have also become widespread, and when this is used in an RTM molding method, improvement in resin impregnation properties is expected. Even so, it is desired to develop a technique capable of molding with high accuracy using a phenol resin.

JP 2001-260238 A

  The present invention is intended to solve the above-mentioned problems, and the resin molded product is accompanied by a decrease in productivity while using a phenol resin as a matrix resin even if it has a complicated shape portion. It is an object to be able to form with high accuracy without any problems.

  In view of this, the present invention applies a gel coat coating to the lower mold and then lays the reinforcing fiber sheet and places a piece at a predetermined position, and then covers the upper mold and covers the upper and lower molds on the outer peripheral side of the predetermined mold. FRP molding is performed by injecting a thermosetting resin from the injection port and filling the entire inside of the mold while impregnating the reinforcing fiber sheet and then heating at a predetermined temperature to cure the thermosetting resin. In the RTM molding method for obtaining a product, the thermosetting resin is a phenol resin, and the placing piece is composed of a combination of a soft resin piece and a hard resin piece so as to fill a gap space having an under part inside the mold. It is characterized by being arranged in.

  Thus, by using a phenolic resin as a matrix resin, it is possible to obtain an FRP molded product that is lightweight, has high mechanical strength, is excellent in heat resistance and flame resistance, and is suitable for space and aircraft parts. By using a combination of a soft resin piece and a hard resin piece, it becomes easy to carry out RTM molding with phenol resin while corresponding to a gap space with an under part, and a complicated shape part Even those having a thickness can be molded with high precision without impairing productivity.

  Further, in this RTM molding method, a soft resin piece is applied by inserting a part thereof into the under part, and a hard resin piece is combined with the soft resin piece in a state in which the part is in close contact with the soft resin piece. When removing the mold, the hard resin piece is removed first, and then the soft resin piece is removed while being elastically deformed. It is possible to easily cope with various shapes. In this case, if the piece made of soft resin is made of silicon resin, it is excellent in elastic deformability and can cope with complicated shapes, and has excellent heat resistance and deformation and deterioration due to the heating process. It becomes difficult to produce.

  Furthermore, in the RTM molding method described above, if the surface of the gel coat coating layer is subjected to a predetermined primer treatment to ensure affinity with the phenol resin, then the reinforcing fiber sheet is laid, The phenolic resin and the gel coat coating layer are firmly bonded to each other to obtain an FRP molded product having excellent durability.

  Furthermore, a phenolic resin is used as the matrix resin, the back side is smoothly finished while having a gel coat coating layer on the front side, and is molded by the RTM molding method described above in a shape having an under part. If it is an FRP molded product characterized by this, it will be a highly accurate molded product that is lightweight and has excellent heat resistance and flame retardancy while ensuring relatively high productivity.

  According to the present invention in which a phenol resin is used as a matrix resin and a placing piece made of a combination of a soft resin piece and a hard resin piece is used, even if it is an FRP molded product having a complicated shape portion, the matrix While using a phenol resin as the resin, it can be molded with high accuracy without causing a decrease in productivity.

It is a flowchart for demonstrating the procedure of the RTM shaping | molding method of embodiment in this invention. It is a perspective view which shows the structure of the lower mold | type used for the RTM shaping | molding method of FIG. It is a perspective view which shows the state which has arranged the surface piece and the placement piece in the lower mold | type of FIG. It is a perspective view which shows the state which set | placed the inside of a type | mold upward, in order to demonstrate the structure of the upper type | mold used for the RTM shaping | molding method of FIG. It is a perspective view which shows the state which performed the gel coat coating to the lower mold | type in the RTM shaping | molding method of FIG. It is a fragmentary longitudinal cross-section which shows the state of the crevice space which has an under part at the time of arranging a reinforcing fiber sheet and a placing piece in order after performing gel coat painting and primer treatment to a lower model in the RTM molding method of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a flowchart showing a molding method according to the present embodiment, but this embodiment relates to a case where an FRP molded product is created by RTM molding. As an example, a lavatory interior part for a passenger aircraft is created. The procedure of the molding method when doing is shown.

  First, a gel coat coating is applied to the inside of the lower mold at a predetermined thickness (S1), and after the coating is dried, a primer treatment is applied for the purpose of increasing the affinity between the matrix resin and the gel coat coating layer (S2). Then, the reinforcing fiber sheet woven in the form of a glass fiber or the like is laid evenly (S3), and a piece is placed at a shape position such as an under part where it is difficult to remove the mold (S4).

  Then, the upper die is placed on the lower die, air is sucked through the suction port from the portion where the outer flanges of the upper and lower die are overlapped, and the upper and lower die are brought into vacuum contact and fixed with a clamp (S5). Then, a thermosetting resin is injected from the injection port of the upper mold (S6), and is filled so that the entire interior of the mold is impregnated into the reinforcing fiber sheet, and then heated at a predetermined temperature for a predetermined time to be thermosetting. The resin is cured (S7), and the upper and lower molds are opened to remove the mold (S8), thereby completing the molding operation and obtaining the desired FRP molded product.

  The procedure itself of this RTM molding method is a well-known one that is also found in conventional examples. However, in the RTM molding method of the present embodiment, a phenol resin is used for the matrix resin, and the placing piece is a soft resin. It consists of a combination of a steel piece and a hard resin piece, and a soft resin piece is applied in a state where a part of the soft resin piece is matched to the under part and inserted into this, and a hard resin piece is part of it Combined in close contact with the soft resin piece, it is supposed to fill the gap space with the under part as a placing piece, and after removing the hard resin piece before removing the mold, It is characterized in that it is configured to be removed while elastically deforming the piece.

  In other words, when performing RTM molding using phenolic resin, in cases where molding is performed including a complicated shape such as a gap space with an under part, the FRP molded product is strong and difficult to deform, so that demolding is possible. Since this creates a part that is not easy, it is necessary to carry out placing pieces that are a complex combination of many pieces, and it is usually difficult to ensure high productivity due to the many labors and costs. It was. Therefore, in the present invention, by using a placing piece that is a combination of a soft resin piece that is easily elastically deformed and a rigid hard resin piece, a complicated shape portion can be obtained by a simple procedure with a minimum number of pieces. However, it can be molded with high accuracy.

  This soft resin piece is preferably made of silicon resin from the viewpoint of ensuring heat resistance and moderate elastic deformability, and the hard resin piece is preferably made of bakelite from the viewpoint of ensuring heat resistance and rigidity. It is. In addition, the primer treatment for gel coat coating is essential in the present embodiment in which phenol is used for the matrix resin.

  The advantage of using phenolic resin is that it is not necessary to mix incombustible substances when molding aircraft parts that require heat resistance and flame retardancy. It becomes easy to spread to complicated shapes, it is possible to adopt the RTM molding method instead of the hand lay-up molding method, and the back side of the molded product is finished smoothly by RTM molding, ensuring high mechanical strength. However, it is possible to reduce the specific gravity lightly.

  FIG. 2 shows a configuration of the placing piece 5 by a combination of the lower die 2, the surface piece 4, and the pieces 5a and 5b used in the RTM molding method of the present embodiment. In this case, a portion recessed from the upper surface to the side surface of the lower mold 2 is the mold interior 20, and the periphery thereof is a flat flange 23, but the surface piece 4 is disposed on one end side of the mold interior 20. Thus, a gap space 25 having an under portion 25a is formed (see FIG. 6).

  FIG. 3 shows a state in which the placing piece 5 by the combination of the pieces 5a and 5b is arranged in the gap space 25 having the under part 25a (see FIG. 6) formed by arranging the surface piece 4 on the lower mold 2. Yes. The piece 5a is made of a soft resin formed in the shape of a ski using silicon resin, and is characterized in that it is relatively easily elastically deformed so that it can be easily attached to and detached from the under portion 25a. On the other hand, the piece 5b is made of a hard resin in which a bakelite is formed in a strip shape having a length about two-fifths of the piece 5a, and is integrally combined with one surface in close contact with the curved side surface portion of the piece 5a. While the placing piece 5 is constituted by these, it is arranged so as to fill a gap space 25 formed between the side surface of the surface piece 4 and the protruding portion 21 formed on the lower mold 2.

  FIG. 4 shows the upper die 3 used by being put on the lower die 2, and is in a state where it is placed upside down from the time of the molding operation in order to explain the configuration of the inside 30 of the die. The mold interior 30 of the upper mold 3 has a convex shape corresponding to the concave shape of the mold interior 20 of the lower mold 2 described above, and the peripheral flange 33 has seal members 31 on the outer peripheral side and the inner peripheral side. 32 is disposed, and the lower die 2 and the upper die 3 are brought into vacuum contact with each other by sucking from the suction port 33a in a state where the lower die 3 is in close contact with the flange 23 of the lower die 3 and the inside of the overlapping portion is sealed. Yes.

  Further, an injection port 30a is opened in the mold interior 30 of the upper mold 3, from which phenol resin is injected. Further, discharge ports 30b and 30c are opened at both ends, and excess air and excess resin due to the injection work are discharged to the outside through this. In the present embodiment, the phenol resin is injected from the injection port 30a at a predetermined pressure and discharged from the discharge ports 30b and 30c by the pressure difference from the atmosphere side. However, a suction line is provided to the discharge ports 30b and 30c. It is also possible to fill the resin while adjusting the injection pressure and the suction pressure by connecting them, whereby the injection pressure can be set low. Moreover, you may arrange | position a piece on a part of upper mold | type 3 as needed as shown in a figure.

  FIG. 5 shows a state in which the gel coat coating layer 20 is provided in a state where the surface piece 4 is arranged on the lower mold 3. The gel coat coating layer 20 is provided so as to cover the surface portion exposed to the outside when the FRP molded product is used. On the surface (matrix resin side), the gel coat coating layer 20 is between the phenol resin having poor adhesion to other resins. In order to increase the affinity, it is necessary to perform a predetermined primer treatment. As this primer treatment, various currently popular means such as a predetermined epoxy acrylate in a semi-cured state can be used.

  FIG. 6 shows a gap space having an under portion 25a when the reinforced fiber sheet 60 and the placing piece 5 are arranged in this order after providing the gel coat coating layer 50 on the lower mold 2 and applying the primer treatment in the RTM molding method described above. 25 states are shown. In the present embodiment, as shown in the figure, an elastically deformable soft resin piece 5a having a shape applied to the under portion 25a is inserted from the side surface side of the surface piece 4 over the under portion 25a, and is made of a hard resin. The placing piece 5 is configured by being combined with the piece 5b inserted between the piece 5b and the protruding portion 21 of the mold interior 30 in close contact with the side surface side of the piece 5a.

  By adopting such a configuration of the placing piece 5, the piece 5 a can be easily elastically deformed at the time of placement and removal and can correspond to the shape of the under portion 25 a, and the soft piece 5 a Combining the pieces 5b with the above, the gap space 25 having the under portions 25a is appropriately filled and can be easily removed from the mold, enabling high-precision molding with the minimum number of pieces and labor. Can be secured.

  As described above, according to the present invention, a resin molded product can be molded with high accuracy without using a phenolic resin as a matrix resin, even if it has a complicated shape portion. It became so.

  2 Lower mold, 3 Upper mold, 4 Surface piece, 5 Place piece, 5a, 5b piece, 20, 30 Inside the mold, 23, 33 Flange, 25 Crevice space, 25a Under part, 30a Inlet, 30b, 30c Outlet, 33a Suction port, 50 gel coat paint layer, 60 reinforced fiber sheet

Claims (5)

After the gel coating is applied to the lower mold, the reinforcing fiber sheet is laid, and a piece is placed at a predetermined position. After that, the upper mold is covered, and the upper and lower molds are closely adhered to each other by a predetermined means. RTM molding to obtain FRP molded product by injecting thermosetting resin from the inlet and filling the entire inside of the mold while impregnating the reinforcing fiber sheet, and then heating at a predetermined temperature to cure the thermosetting resin In the method
The thermosetting resin is a phenol resin, and the placing piece is a combination of a soft resin piece and a hard resin piece, and is arranged so as to fill a gap space having an under part inside the mold. An RTM molding method.   The soft resin piece is applied by inserting a part of the piece into the under part, and the hard resin piece is combined with the soft resin piece in a state where the part is in close contact with the soft resin piece. 2. The RTM molding method according to claim 1, wherein, at the time of demolding, the hard resin piece is removed first, and then the soft resin piece is removed while being elastically deformed.   The RTM molding method according to claim 2, wherein the soft resin piece is made of silicon resin.   The surface of the gel coat coating layer is subjected to a predetermined primer treatment for ensuring affinity with a phenolic resin, and then the reinforcing fiber sheet is laid down. RTM molding method.   The phenol resin is used for the matrix resin, and the back side is smoothly finished while having the gel coat coating layer on the front side, and the shape having the under part is claimed in claim 1, 2, 3 or 4. An FRP molded product formed by the RTM molding method.

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