JP2009039955A - Molding method of composite material - Google Patents

Abstract

In a method for molding a composite material such as FRP (fiber reinforced plastic), the fiber content Vf of a molded product can be reduced even if the size of the preform is varied when the preform is arranged in a molding die. Make uniform.
A preform made of a fiber reinforced base material is housed in a cavity of a mold made up of an upper die 1, a lower die 2 and a middle die 3 divided into a plurality of surfaces, and pressed on one surface of the preform. A mold clamping step for applying a constant pressure to the portion of the middle mold that comes into contact, an injection step for injecting a resin material into the preform, and the constant pressure applied to the portion of the mold is increased to a predetermined pressure and held. And a holding step. A method of forming a composite material, comprising:
[Selection] Figure 2

Description

  The present invention relates to a manufacturing method for FRP (fiber reinforced plastic), and more particularly, to a method for manufacturing FRP having uniform performance while suppressing variation in fiber content of a molded product.

  Patent Document 1 relates to an invention whose name is “FRP manufacturing method and manufacturing apparatus”, in which a reinforcing fiber base material is disposed in a cavity of a molding die divided into a plurality of surfaces, and then a resin is injected. In the manufacturing method of FRP to be cured, a resin injection tube for injecting resin into the cavity and / or a resin discharge tube for discharging excess resin in the mold are provided on the mating surfaces of the molds. There is disclosed a method for manufacturing FRP, characterized in that a pressure is sandwiched between mold-matching surfaces, and then resin is injected and discharged into the cavity.

  Patent Document 2 relates to an invention whose name is “manufacturing method and manufacturing apparatus of fiber reinforced composite material”, and impregnating a liquid matrix resin into a preform formed by laminating at least a plurality of reinforcing fiber base materials and curing the preform. In the fiber-reinforced composite material manufacturing method, the preform is placed in a mold, the whole is sealed so as to cover the preform inside the diaphragm attached to the chamber, and then formed between the mold and the diaphragm, A fiber reinforced composite material characterized in that a liquid matrix resin is infiltrated into the preform under reduced pressure while reducing the pressure inside the inner space including the preform and preventing the preform from expanding by pressurizing the outside of the diaphragm. The manufacturing method is disclosed.

  Patent Document 3 relates to an invention whose name is “molding material curing device”, and at least a pair of molds are arranged along a conveyance path, and a cavity formed by these molds is formed into a required shape by a shaping device. The molded semi-cured molding material is heated and cured, and at least a part of the mold is a movable mold that changes the cavity cross section following the expansion and contraction that occurs in the molding material during the curing process. An apparatus for curing a molding material is disclosed.

  In the conventional FRP (fiber reinforced plastic) mold, for example, as the molding die shown in Patent Document 1, the structure is a fixed size structure and the volume of the cavity is constant. If there is a variation in size of the preform, the preform is forcibly compressed to a predetermined position in the mold. Therefore, when the dimensions at the time of manufacturing the preform are larger than the target dimensions, the remaining space in the volume of the preform that is forcibly compressed to a predetermined position in the mold is reduced, and as a result, the resin material In the FRP molded product manufactured by injecting the resin, the resin volume decreases and the fiber content Vf (volume fiber) increases. On the other hand, when the size of the preform is smaller than the target size, the resin volume increases and the fiber content Vf (volume fiber) decreases, contrary to the above. There is a concern that the above-described variation in the Vf of the molded product based on the dimensional error during the manufacture of the preform may affect the performance of the FRP, particularly the impact performance.

  Patent Document 2 discloses a method for producing a fiber-reinforced composite material that keeps the fiber content Vf constant during and after molding in a VaRTM (Vacuum Assisted Resin Transfer Molding) method using a preform. As described above, the preform placed on the mold is sealed so as to be covered with the diaphragm, and the matrix resin is infiltrated while preventing the preform from bulging by applying pressure from the outside of the diaphragm. This method is basically different from the molding method described above, and does not suggest a measure for variation in dimensions during the production of the preform.

  Patent Document 3 describes a semi-cured molding material obtained by impregnating a reinforced fiber such as glass fiber with an unsaturated polyester resin or an epoxy resin in which a high-temperature curing agent is blended. Since the movable mold that changes the cavity cross section following the expansion and contraction that occurs in the molding material during the heat curing process is disclosed, this method is basically different from the molding method of Patent Document 1. It does not suggest countermeasures for dimensional variations during renovation production.

JP 2005-169786 A JP 2005-262560 A JP-A-6-206232

  According to the present invention, in the manufacture of FRP (fiber reinforced plastic), there is a variation in the fiber content Vf of the molded product due to a variation in the size of the preform disposed in the molding die. An object of the present invention is to provide a method of manufacturing FRP that solves the problem of the conventional technology that the performance of molded products, particularly impact performance, is not uniform.

  In order to solve the above-mentioned problems, the method for molding a composite material according to the present invention is a method in which a preform is accommodated and pressed in a cavity of a molding die divided into a plurality of surfaces and is in contact with one surface of the preform. A mold clamping step for applying a constant pressure to the mold portion, an injection step for injecting a resin material into the preform, and a holding step for increasing the constant pressure applied to the mold portion to a predetermined pressure and holding it. It is characterized by comprising.

  In addition, the FRP molding method according to the present invention includes a molding die in which a preform made of a fiber reinforced base material is housed and pressed in a cavity of a molding die divided into a plurality of surfaces and is in contact with one surface of the preform. A mold clamping step for applying a constant pressure to the portion, an injection step for injecting a resin material into the preform, and a holding step for increasing the constant pressure applied to the portion of the mold to a predetermined pressure and holding it. It is characterized by comprising.

  Based on the above configuration, the pressure can be applied to the mold part independently of the other parts, so that the same pressure can be applied even if the size of the preform varies.

  The FRP molding method according to the present invention is characterized in that in the holding step, the resin material is heated while being held in a mold.

  The FRP molding method according to the present invention is characterized in that, in addition to the above features, the fiber reinforced base material is carbon fiber or glass fiber, and the resin material is an epoxy resin or a polyester resin. .

  Furthermore, in the above-described molding method of the present invention, the molding die divided into the plurality of surfaces includes an upper die, a lower die, and a middle die, and the portion of the molding die is a middle die. .

  Since the present invention can apply a certain pressure to the preform accommodated in the cavity of the mold based on the configuration described in the claims, even if there is a variation in size during the production, By using an apparatus with a simple configuration, the fiber content Vf of the molded product is made uniform and the performance is made uniform at low cost and in a short time.

  1, 2 and 3 relate to an embodiment of the present invention. FIG. 1 shows a state at the time of clamping, FIG. 2 at the time of injection of a resin material, and FIG. 3 at a time of holding pressure.

  In the mold clamping process shown in FIG. 1, a preform 4 made of a fiber reinforced base material is stored in a mold block made up of an upper mold 1, a lower mold 2, and a middle mold 3, and then pressed. By applying pressure P to the middle mold independently of the mold, even if there is a variation in the volume of the preform, it is compressed at a constant compression rate. As the fiber reinforced material, carbon fiber, glass fiber, or the like is used.

  In the resin material injection step shown in FIG. 2, the matrix resin material is injected by the resin injection cylinder 5 into the uniformly compressed space of the preform 4. As the resin material, an epoxy resin, a polyester resin, or the like is used.

  In the pressure-holding step shown in FIG. 3, after the resin material injection step is finished, the pressure P applied to the middle mold 3 is slightly increased (α) and the pressure-holding state is continued for a while, while the resin material is kept at 70 to 150. Heat at a temperature of ° C. Although not shown, the heating means may be a method in which high temperature water is supplied from the outside into the mold and circulated, or a method using a heater.

  FIG. 4 shows a modification of part of the embodiment, and shows an example in which an O-ring 6 is provided to prevent the resin material from leaking from the sliding surfaces of the lower mold 2 and the middle mold 3. . Sealing materials other than O-rings may be used.

  FIG. 5 shows another modification of the embodiment, and shows an example in which the middle mold is divided into two parts 7 and 8 and a cushioning material 9 is inserted therebetween. A spring, a gas spring or the like is used as the buffer material.

  FIG. 6 shows still another modification of the embodiment, and includes a lock device 10 that fixes a part of the middle mold by mechanical means at the time of holding pressure. This is an effective means when there is a large difference in the initial pressure (α is large) or when the pressure holding time is long.

  The present invention is applicable to the manufacture of FRP and the manufacture of molded articles made of other composite materials.

The form of the clamping process is shown regarding the Example of this invention. The form of the injection process of the resin material is shown regarding the Example of this invention. The embodiment of the pressure holding process will be described with respect to the embodiment of the present invention. The modification of the one part of the Example of this invention is shown, and the example which provided the O-ring in the middle type is shown. FIG. 5 shows another modification of the embodiment of the present invention, in which an intermediate mold is divided into two parts and a cushioning material is inserted between them. FIG. 10 shows still another modification of the embodiment of the present invention, and shows an example provided with a lock device for fixing a part of the middle mold by mechanical means at the time of holding pressure.

Explanation of symbols

1: Upper mold,
2: Lower mold,
3: Medium size
4: Preform,
5: Resin injection cylinder
6: O-ring,
7: Medium size (preform action part),
8: Medium size (external force acting part),
9: cushioning material,
10: Locking device

Claims (6)

A mold clamping step of storing a preform in a cavity of a molding die divided into a plurality of surfaces and sandwiching the preform, and applying a constant pressure to a portion of the molding die in contact with one surface of the preform;
An injection step of injecting a resin material into the preform;
A holding step of increasing and holding the constant pressure applied to the part of the mold to a predetermined pressure;
A method for forming a composite material, comprising: In the shaping | molding method described in Claim 1,
The molding method divided into a plurality of surfaces includes an upper die, a lower die, and a middle die, and the portion of the molding die is a middle die. A mold clamping step in which a preform made of a fiber reinforced base material is housed in a cavity of a molding die divided into a plurality of surfaces and clamped, and a constant pressure is applied to a portion of the molding die in contact with one surface of the preform; ,
An injection step of injecting a resin material into the preform;
A holding step of increasing and holding the constant pressure applied to the part of the mold to a predetermined pressure;
A method for molding FRP, comprising: In the holding step of the manufacturing method according to claim 3,
A method for molding FRP, wherein the resin material is heated while being held in a mold. In the manufacturing method described in Claim 3 or 4,
The fiber-reinforced base material is carbon fiber or glass fiber, and the resin material is epoxy resin or polyester resin. A method as claimed in any one of claims 3 to 5,
The FRP molding method, wherein the molding die divided into a plurality of surfaces includes an upper die, a lower die, and a middle die, and the portion of the molding die is a middle die.

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