JP6230083B1 - Manufacturing method and demolding method of fiber reinforced resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a fiber reinforced resin molded article by press molding efficiently in a short time and with low energy. A step of preparing an upper die and a lower die, wherein at least one of the upper die and the lower die is provided with a resin layer on a surface in contact with a prepreg, and the lower die A step of disposing a prepreg thereon, a step of forming a fiber-reinforced resin molded product by pressing the prepreg with the upper mold and the lower mold, and the upper mold and the lower mold A step of separating the upper mold and the lower mold from each other from a state in which the fiber reinforced resin molded product is sandwiched between the fiber reinforced resin molded product, the fiber reinforced resin molded product, and the fiber reinforced resin molded product A method of producing a fiber reinforced resin molded product from a prepreg by press molding, which includes a step of removing the fiber reinforced resin molded product from a mold by spraying a cooling gas on the resin layer. [Selection] Figure 4

Description

  The present invention relates to a method for producing a fiber-reinforced resin molded product by press molding, and a method for releasing from a mold.

  A fiber reinforced resin molded article composed of a resin such as epoxy and a fiber bundle can be produced by curing a prepreg obtained by impregnating and drying an epoxy resin into a fiber bundle by heating and pressing. As described in paragraph [0022] of Patent Document 1, conventionally, autoclave molding, vacuum bag molding, RTM method, and press molding have been used for such production.

  Among these, the press molding method is desirable from the viewpoint of high productivity and a good quality fiber-reinforced resin molded product.

International Publication No. 2013/081058 Pamphlet

  However, unlike a metal material, a prepreg is liable to adhere to a cured prepreg during press molding. When the attached molded prepreg is removed from the mold (demolded), it is necessary to cool the mold, and the productivity per unit time is lowered due to the cooling time. Conventionally, water cooling or oil cooling has been used to cool the entire mold, but it takes time for cooling, and when continuously manufacturing fiber reinforced resin molded products after cooling, the cooled mold Had to be heated to the original temperature, and it took a long time to continuously produce the fiber-reinforced resin molded product.

  An object of this invention is to provide the method of manufacturing a fiber reinforced resin molded article by press molding efficiently in a short time and with low energy.

  As a result of extensive research, the present inventor has reached the present invention. That is, one of the present invention is a step of preparing an upper die and a lower die, wherein at least one of the upper die and the lower die is provided with a resin layer on a surface in contact with a prepreg. A step of disposing a prepreg on the lower mold, a step of forming a fiber-reinforced resin molded product by pressing the prepreg with the upper mold and the lower mold, and the upper mold. A step of separating the upper mold and the lower mold from each other from a state in which the fiber reinforced resin molded product is sandwiched between the upper mold and the lower mold, the fiber reinforced resin molded product, and the fiber reinforced resin. A method of producing a fiber reinforced resin molded product by press molding from a prepreg, including a step of removing the fiber reinforced resin molded product from a mold by blowing a cooling gas to the resin layer to which the molded product is adhered. is there.

  In the production method of the present invention, the molded prepreg (fiber reinforced resin molded product) attached to the mold can be removed in a short time, so that an improvement in productivity can be expected. Moreover, since it is not necessary to cool the mold until it reaches the same temperature as the fiber-reinforced resin molded product to be removed, the temperature rise and fall are small and energy consumption can be suppressed. Furthermore, a three-dimensional fiber reinforced resin molded product can also be manufactured.

FIG. 1 is a view when a prepreg is arranged in a lower mold. FIG. 2 is a view showing a state where the upper mold is lowered, the prepreg is sandwiched between the upper mold and the lower mold, and heated while being pressurized. FIG. 3 is a view when the upper mold is raised and returned to the original position. The molded prepreg is attached to the lower mold. FIG. 4 is a cross-sectional view when the prepreg is press-molded. FIG. 4A is a diagram showing a state where the upper mold is lowered to the prepreg arranged in the lower mold. FIG. 4B is a diagram showing a state where the prepreg is press-molded between the convex portion of the upper mold and the concave portion of the lower mold. FIG. 4 (c) shows a case where a cooling gas is blown onto the resin layer provided in the lower mold when the upper mold and the lower mold are separated from each other and the molded prepreg (fiber reinforced resin molded product). It is a figure which shows the state which has shape | molded.

  In this specification, the fiber-reinforced resin molded product is a prepreg that is a composite of a fiber base material and a thermosetting resin, a thermoplastic resin, or a resin composition, and is molded into a predetermined shape by heating and pressing. It is obtained by this. Therefore, in this specification, the material before molding is referred to as a prepreg, and the material after molding is referred to as a fiber-reinforced resin molded product.

  The prepreg is a composite of a thermosetting resin or a thermoplastic resin with a fiber base material such as carbon fiber or glass fiber. As a specific example, a thermosetting resin or a fiber base material is used. Examples include those obtained by coating (impregnating) a thermoplastic resin, drying and heating, and semi-curing.

  The fiber base material in the prepreg is preferably a carbon fiber material having a thickness of 0.03 mm to 0.5 mm, but is not limited thereto.

  As the resin used as the material for the prepreg, either a thermosetting resin or a thermoplastic resin can be used, but a thermosetting resin that cures at about 100 to 150 ° C. is preferable. Examples of the thermosetting resin include epoxy resins, vinyl ester resins, unsaturated polyester resins, polyurethane resins, phenol resins, and the like, and these can be used in combination.

  Moreover, you may use a thermoplastic resin for the prepreg in this invention. The thermoplastic resin that can be used is not particularly limited, but a resin having a melting point lower by 30 ° C. than the melting point of the resin covering the mold is preferable, and a resin having a melting point lower by 50 ° C. is more preferable. . Specific examples include acrylic resin, polyester resin, polycarbonate resin, polypropylene resin, polyethylene resin, polystyrene resin, vinyl chloride resin, and polyamide resin. These may be used alone or in combination.

  In this specification, the fiber reinforced resin molded product is a fiber reinforced resin / metal integrated molded product obtained by heating and pressing a prepreg composed of a fiber base material and a resin and a metal such as aluminum, iron, titanium, and the like. Shall be included.

[Method for producing fiber-reinforced resin molded product]
The manufacturing method of the fiber reinforced resin molded product of the present invention is as follows. That is, a step of preparing an upper die and a lower die, wherein at least one of the upper die and the lower die is provided with a resin layer on a surface in contact with a prepreg; A step of arranging a prepreg, a step of forming a fiber-reinforced resin molded product by pressing the prepreg with the upper die and the lower die, and the upper die and the lower die. The step of separating the upper mold and the lower mold from each other from the state in which the fiber reinforced resin molded product is sandwiched therebetween, the fiber reinforced resin molded product, and the fiber reinforced resin molded product are attached. A method of manufacturing a fiber reinforced resin molded product from a prepreg by press molding, including a step of removing the fiber reinforced resin molded product from a mold by spraying a cooling gas on the resin layer.

  In the present invention, press molding is performed by sandwiching between both molds using an upper mold and a lower mold. The upper mold and the lower mold can have a predetermined shape in order to form a fiber-reinforced resin molded product. For example, the upper die and the lower die can have flat surfaces on the pressing side. By doing in this way, a flat fiber reinforced resin molded product can be shape | molded. As another aspect, a convex portion is provided on one side of the upper die and the lower die, and a concave portion corresponding to the convex portion (where the convex portion can enter) is provided on the other side. Can do. By doing in this way, since a prepreg will be pinched | interposed into a convex part and a recessed part, the fiber reinforced resin molded product obtained can have a three-dimensional shape.

  At least one of the upper mold and the lower mold used in the present invention includes a resin layer on the surface in contact with the prepreg. The resin layer may be provided in either the upper mold or the lower mold, or may be provided in both the upper mold and the lower mold. When the upper mold and the lower mold are provided with a convex portion or a concave portion, a resin layer can be provided on the convex portion or the concave portion.

  Although the thickness of the resin layer used for a metal mold | die is not specifically limited, 0.1 mm-3 cm are preferable and 1 mm-1 cm are more preferable.

  The resin of the resin layer used in the mold is not particularly limited, but as described above, a resin having a melting point higher by 30 ° C. than the melting point of the prepreg resin is preferable. Examples of such a resin include cyanate resin, polycarbonate resin, acrylic resin, polyester resin, polypropylene resin, polyethylene resin, polystyrene resin, vinyl chloride resin, and polyamide resin.

  The resin layer used in the mold can contain a component that enhances the heat dissipation effect. Although it does not specifically limit as a component which improves a thermal radiation effect, Carbon fiber can be included from a viewpoint that it is easy to handle, and a viewpoint that heat dissipation is high. That is, the resin layer is preferably composed of a composite material of carbon fiber and resin. When the resin layer is composed of a composite material, a specific example is a method in which carbon fibers are used as the core material of the resin layer.

  The press molding of the production method of the present invention is performed by sandwiching a prepreg between an upper mold and a lower mold, and heating and pressing. The mold temperature at the time of heating is not particularly limited, but is usually 120 to 160 ° C. when the prepreg uses a thermosetting resin, and usually when the prepreg uses a thermoplastic resin. 230-290 ° C.

  Although it does not specifically limit also about the pressure in the case of pressurization, Usually, it is 1 Mpa-8 Mpa.

  After press molding, the upper mold and the lower mold are separated from each other. At this time, the molded prepreg (fiber-reinforced resin molded product) is attached to either the upper mold or the lower mold. In order to remove the adhering fiber reinforced resin molded product, it is necessary to cool the fiber reinforced resin molded product and the mold. In the manufacturing method of the present invention, cooling is performed using a cooling gas.

  Specifically, the fiber reinforced resin molded product attached to either the upper mold or the lower mold is demolded by cooling the resin layer in which the cooling gas is disposed on the fiber reinforced resin molded product and the mold. The cooling gas used is not particularly limited, but it is preferable to use air of −30 ° C. or more and −5 ° C. or less. For example, as a device for producing air at about −20 ° C., “Jet Cooler (trade name)” manufactured by Nippon Seiki Co., Ltd. can be cited.

  By providing the press surface of the mold with a resin layer that radiates heat more easily than metal, the entire resin layer can be cooled and demolded in a short time even when a part of the resin layer is cooled. The cooling time is not particularly limited, but is usually 5 to 60 seconds.

  In addition, by providing a resin layer, even if the press surface of the mold has a convex part and a concave part, the entire resin layer is cooled by transmitting the cooling to the part where the cooling gas is not sprayed. Therefore, demolding becomes easy.

  The mold temperature after demolding is about 110 ° C. to 150 ° C. if the prepreg uses a thermosetting resin. Moreover, when using a thermoplastic resin, it is 220 to 280 degreeC. The mold temperature can be suppressed to a decrease of about −5 ° C. to −10 ° C.

  The fiber reinforced resin molded article thus obtained is obtained by molding a fiber reinforced resin according to the application and shape, and can be used for parts such as aircraft and automobiles.

  Next, the present invention will be described in detail using examples. It should be noted that the present invention is not limited to the embodiments, and the design can be changed as appropriate within a range well known to those skilled in the art.

  An apparatus for manufacturing a fiber reinforced resin molded product by heating and pressing a prepreg by press molding for carrying out the manufacturing method of the present embodiment is a press molding including an upper mold 3 and a lower mold 4 as shown in FIG. Use machine 1. The press molding machine 1 can move the upper mold 3 up and down, and can compress (press) an object between the upper mold 3 and the lower mold 4. The press molding machine 1 includes an upper mold heating unit 6 and a lower mold heating unit 7, and can heat the upper mold 3 and the lower mold 4 respectively. Further, the press molding machine 1 includes cooling gas blowing parts 51 and 51 for guiding cooling gas to be blown over a wide range and cooling gas guiding pipes 52 and 52 for guiding the cooling gas.

  The upper mold 3 of the present embodiment is provided with a convex portion 31, on which an upper mold resin layer 32 containing carbon fibers is disposed, and the lower mold 4 is provided with a concave portion 41, on which And a lower mold resin layer 42 containing carbon fibers (see FIG. 4A). The convex portion 31 can enter the concave portion 41. Each of the upper mold resin layer 32 and the lower mold resin layer 42 is a cyanate resin having a thickness of 1 cm and a melting point of 400 ° C.

  Next, manufacture of a fiber reinforced resin molded product will be described. First, in this embodiment, since an epoxy resin prepreg is used, the upper mold 3 and the lower mold 4 are heated to about 120 ° C. to 160 ° C. Next, the prepreg 2 of the carbon fiber-containing epoxy resin is disposed near the center on the lower mold 4. At this time, the prepreg 2 is preheated if necessary. This state is shown in FIG. In addition, when manufacturing the above-mentioned fiber reinforced resin and metal integrated molded product, a prepreg is arrange | positioned on metal, such as sheet-like iron, aluminum, and titanium.

  Then, the upper die 3 is moved downward, the prepreg 2 is sandwiched between the upper die 3 and the lower die 4 and pressed. The pressure at this time is about 3 MPa. The pressing time is about 60 seconds. The state at this time is shown in FIG.

  By the heating and pressurization described above, the prepreg 2 is molded, and a molded prepreg 21 (fiber reinforced resin molded product 21) is obtained.

  In order to take out the manufactured fiber-reinforced resin molded product 21, the upper mold 3 is raised (see FIG. 3). At this time, the fiber reinforced resin molded product 21 is attached to the surface of the lower mold 4 (the surface of the lower mold resin layer 42). At this time, both the fiber reinforced resin molded product 21 and the lower mold 4 are at a high temperature, and the fiber reinforced resin molded product 21 cannot be removed from the lower mold 4 immediately.

  In order to demold the fiber reinforced resin molded product 21, the cooling gas guided by the cooling gas guide pipes 52, 52 is supplied from the cooling gas blowing parts 51, 51 to the fiber reinforced resin molded product 21 and the lower mold resin layer 42. Spray from side to side.

  The cooling gas outlets 51 and 51 preferably have a blower outlet having a shape closer to a flat shape than a round shape so as to cover the fiber reinforced resin molded product 21 from the side in a wide range.

  When the cooling gas is sprayed, the fiber reinforced resin molded product 21 and the lower mold resin layer 42 of the lower mold 4 are instantaneously cooled, and the fiber reinforced resin molded product 21 can be removed. The cooling gas is blown onto a part of the lower mold resin layer 42, whereby the entire lower mold resin layer 42 is cooled.

  Here, as the cooling gas, a “jet cooler (trade name)” manufactured by Nippon Seiki Co., Ltd. was used as an apparatus for producing air of about −20 ° C.

  The time taken to demold the fiber reinforced resin molded product 21 is about 10 seconds after the cooling gas is blown, and is a very short time.

  As described above, the method for producing a fiber-reinforced resin molded product of the present invention is a method of spraying a cooling gas toward a fiber-reinforced resin molded product attached to a mold and a resin layer provided on the mold surface. The adhesion portion with the reinforced resin molded product is rapidly cooled and can be taken out.

  When the thermoplastic resin is impregnated instead of the thermosetting resin, for example, a prepreg 2 is preliminarily heated to form a preform, and then heated and pressed (press-molded) to produce fibers. A reinforced resin molded product can be manufactured. The demolding method at this time is similar to that already described, but the heating temperature is preferably set to a higher mold temperature than when a thermosetting resin is used.

[Demolding process]
Next, demolding in the manufacturing method of the fiber reinforced resin molded product 21 will be described in detail with reference to cross-sectional views. FIG. 4A is a cross-sectional view of the upper mold 3, the lower mold 4, and the prepreg 2 at the time of molding. First, the prepreg 2 is placed on the lower mold 4 having the recess 41. The upper mold 3 having the convex portion 31 is lowered with respect to the lower mold 4, and the prepreg 2 is sandwiched between the upper mold 3 and the lower mold 4 (FIG. 4B). At this time, the prepreg 2 is heated and pressurized.

Next, the upper mold 3 and the lower mold 4 are separated from each other. At this time, the molded prepreg 21 (fiber reinforced resin molded product 21) is attached to the lower mold 4. The lower mold 4 including the attached fiber reinforced resin molded product 21 and the lower mold resin layer 42 is cooled to remove the fiber reinforced resin molded product 21 (FIG. 4C). Cooling is performed by blowing a cooling gas from the cooling gas blowing portions 51 and 51 guided to the cooling gas guide pipes 52 and 52 to a part of the fiber reinforced resin molded product 21 and the lower mold resin layer 42. Even when a part of the lower mold resin layer 42 is cooled, the mold center part (near part B) shown in FIG. The entire layer 42 is cooled and can be demolded. Without the lower mold resin layer 42, it takes time to cool the metal surface, and the time required for demolding becomes longer.
In the present embodiment, the case where the fiber reinforced resin molded article 21 is attached to the lower mold 4 has been described. However, when the fiber reinforced resin molded article 21 is attached to the upper mold 3, the molded prepreg 21 (fiber reinforced resin molded article), A cooling gas is blown onto the upper mold resin layer 32 to remove the mold.

  As shown in FIG. 4, the upper mold 3 and the lower mold 4 are such that the opposite side of the upper mold resin layer 32 and the lower mold resin layer 42 is the upper mold hollow portion 33 and the lower mold hollow. It is preferable that the portion 43 is hollowed out. Note that the upper mold hollow portion 33 and the lower mold hollow portion 43 mean portions where the opposite surfaces facing the surface with which the prepreg 2 contacts in the upper mold 3 or the lower mold 4 are hollowed out. The shapes of the upper mold hollow portion 33 and the lower mold hollow portion 43 may be rectangular parallelepiped shapes or other shapes. Moreover, although the magnitude | size of a hollow part is not specifically limited, It can be 50%-80% with respect to the volume of the whole metal mold | die. Further, not only can a mold be produced by hollowing out a metal ingot, but also a mold can be produced by combining and joining plate-like metals. A mold manufactured by combining plate materials in this way is also within the scope of the present invention. When manufactured by combining plate materials, a large hollow portion can be provided while suppressing waste.

  In the case of the present embodiment, since the mold is not cooled with water, it is not necessary to dispose a water cooling tube in the mold, so that the hollow portions 33 and 43 can be provided in the mold. The mold has a gripping part if necessary, and of course, the mold having a necessary shape can be replaced. However, in the present invention, the hollow parts 33 and 43 are formed by having the hollow parts 33 and 43. Compared to an ingot-shaped mold that does not have, the weight will be reduced by about 2/3 to 1/2, the mold can be easily replaced, and the temperature rise due to heating is faster, preferable.

  Moreover, the fiber-reinforced resin molded product of the present invention can be produced not only in a three-dimensional sheet shape but also in other shapes.

Hereinafter, the effect of the present embodiment will be described.
[effect]
[1] A step of preparing an upper die and a lower die, wherein at least one of the upper die and the lower die is provided with a resin layer on a surface in contact with a prepreg; A step of arranging a prepreg, a step of forming a fiber-reinforced resin molded product by pressing the prepreg with the upper mold and the lower mold, and the upper mold and the lower mold. A step of separating the upper mold and the lower mold from each other from a state in which the fiber reinforced resin molded product is sandwiched between the fiber reinforced resin molded product, the fiber reinforced resin molded product, and the fiber reinforced resin molded product attached. A method of producing a fiber reinforced resin molded article from a prepreg by press molding, including a step of removing the fiber reinforced resin molded article from a mold by blowing a cooling gas onto the resin layer. And low energy fiber A reinforced resin molded product can be manufactured by press molding.
[2] In the method according to [1], the upper mold includes a convex portion and the lower mold corresponds to the convex portion so that the fiber-reinforced resin molded product has a three-dimensional shape. When the concave portion is provided, a three-dimensional fiber reinforced resin molded product can be manufactured.
[3] In the method according to the above [1] or [2], when the resin layer is made of a composite material containing carbon fiber, the heat dissipation of the resin layer is increased, and the resin layer is instantaneously cooled by a cooling gas. Demolding is possible.
[4] In the method according to any one of [1] to [3], when the resin layer is made of a cyanate resin or a polycarbonate resin, the resin layer maintains a stable shape even at a high press molding temperature. be able to.
[5] In the method according to any one of [1] to [4], when the prepreg includes an epoxy resin and a carbon fiber base material, the epoxy fiber reinforced resin having a wide range of uses. A molded product can be obtained.
[6] In the method according to any one of [1] to [5], even if the temperature of the cooling gas is −30 ° C. or higher and −5 ° C. or lower, demolding is possible in a short time. It is.
[7] A step of separating the upper mold and the lower mold from each other from a state in which a fiber-reinforced resin molded product is sandwiched between the upper mold and the lower mold after the press molding, At least one of the mold and the lower mold is provided with a cooling gas on the step of providing a resin layer on the press surface, the fiber reinforced resin molded product, and the resin layer to which the fiber reinforced resin molded product is attached. The method of demolding the press-molded fiber reinforced resin molded article, including the step of removing the fiber reinforced resin molded article from the mold, is a fiber reinforced resin molded article that is efficient and low energy in a short time. Can be removed from the mold.

1 Press molding machine 2 Prepreg 21 Fiber reinforced resin molded product (Molded prepreg)
3 Upper mold 31 Convex part 32 Upper mold resin layer 33 Upper mold hollow part 4 Lower mold 41 Recess 42 Lower mold resin layer 43 Lower mold hollow part 51 Cooling gas blowing part 52 Cooling gas guide pipe 6 Upper metal Mold heating unit 7 Lower mold heating unit

Claims (6)

A step of preparing an upper die and a lower die, wherein at least one of the upper die and the lower die is provided with a resin layer made of a composite material containing carbon fibers on a surface in contact with a prepreg;
Placing a prepreg on the lower mold;
Forming a fiber reinforced resin molded article by pressing the prepreg with the upper mold and the lower mold;
A step of separating the upper mold and the lower mold from each other from a state in which the fiber-reinforced resin molded product is sandwiched between the upper mold and the lower mold;
Pressing from the prepreg, including the step of removing the fiber reinforced resin molded article from the mold by blowing a cooling gas to the fiber reinforced resin molded article and the resin layer to which the fiber reinforced resin molded article is adhered. A method for producing a fiber-reinforced resin molded product by molding.   The method according to claim 1, wherein the upper mold includes a convex portion and the lower mold includes a concave portion corresponding to the convex portion so that the fiber-reinforced resin molded article has a three-dimensional shape. The method according to claim 1, wherein the resin layer is made of a cyanate resin or a polycarbonate resin containing carbon fibers. The method according to claim 1, wherein the prepreg includes an epoxy resin and a carbon fiber substrate. The method as described in any one of Claims 1 thru | or 4 whose temperature of a cooling gas is -30 degreeC or more and -5 degrees C or less. After press molding, a step of separating the upper mold and the lower mold from each other from a state in which a fiber reinforced resin molded product is sandwiched between the upper mold and the lower mold, the upper mold and At least one of the lower molds is provided with a resin layer made of a composite material containing carbon fibers on the press surface;
  A step of removing the fiber reinforced resin molded article from the mold by blowing a cooling gas to the fiber reinforced resin molded article and the resin layer to which the fiber reinforced resin molded article is adhered. A method for demolding a fiber-reinforced resin molded product.