JP6075675B1 - Demolding method of fiber reinforced composite material molding - Google Patents

Abstract

An object of the present invention is to provide a method for producing a fiber-reinforced composite material molded article from a prepreg, in which a press-molded fiber-reinforced composite material molded article is efficiently and quickly demolded in a short time. To do. A method for removing a molded product of a fiber reinforced composite material produced by press molding from a prepreg, wherein the fiber reinforced composite material molded product is sandwiched between an upper mold and a lower mold after press molding. The upper mold and the lower mold are separated from each other, and the fiber-reinforced composite material molded article adhered to one of the press surfaces of the upper mold and the lower mold. Spraying a cooling gas between the press surface and removing the fiber-reinforced composite material molded article from the mold. [Selection] Figure 4

Description

  The present invention relates to a method of releasing a press-molded fiber-reinforced composite material molded product from a mold.

  A fiber reinforced composite material 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 good quality fiber-reinforced composite material 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 cured 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. However, it takes time, and when continuously molding a fiber-reinforced composite material after cooling, the cooled mold is used. It had to be heated to the original temperature, and it took much time to continuously produce the fiber-reinforced composite material molded product.

  An object of the present invention is to provide a method for producing a fiber-reinforced composite material molded article from a prepreg by demolding a press-molded fiber-reinforced composite material molded article in a short time, efficiently and with low energy. And

  As a result of extensive research, the present inventor has reached the present invention. That is, one of the present invention is a method of demolding a fiber reinforced composite material molded product produced from a prepreg by press molding, and after press molding, a fiber reinforced composite between an upper mold and a lower mold. A step of separating the upper mold and the lower mold from the state in which the material molded article is sandwiched; and a fiber-reinforced composite material molded article attached to one press surface of the upper mold and the lower mold; And a step of spraying a cooling gas between the press surface to which the fiber reinforced composite material is adhered, and removing the fiber-reinforced composite material molded article from the mold.

  In the production method of the present invention, the cured prepreg adhering to the mold can be removed in a short time. In addition, since it is not necessary to cool the mold until it reaches the same temperature as the cured prepreg that can be removed, the temperature rise and fall are small and energy consumption can be suppressed.

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 die is lowered, the prepreg is sandwiched between the upper die and the lower die, and heated while being pressurized. FIG. 3 is a view when the upper mold is returned to the original position. The prepreg is attached to the upper mold. FIG. 4 is a perspective view A of the upper mold. FIG. 5 is a side view of the upper mold. FIG. 6 is a perspective view B of the upper mold. It is the state turned over from the state of perspective view A. FIG. 7 is a cross-sectional view of the upper mold.

  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.

[How to demold fiber-reinforced composite material molded products]
In the present specification, a fiber-reinforced composite material molded article is obtained by heating and pressurizing a composite of a fiber base and a thermosetting resin, a thermoplastic resin, or a resin composition. The prepreg is a semi-cured product obtained by applying (impregnating) a thermosetting resin or a thermoplastic resin to a fiber base material such as carbon fiber or crow fiber, and drying and heating the fiber base material. is there. As the fiber base material, a carbon fiber material having a thickness of 0.03 mm to 0.5 mm is preferable. Moreover, as resin used as a material of the prepreg in this invention, although both a thermosetting resin and a thermoplastic resin can be used, the thermosetting resin hardened | cured at about 100-150 degreeC is preferable. Preferred thermosetting resins include epoxy resins, vinyl ester resins, unsaturated polyesters, polyurethanes, phenol resins, and the like. Moreover, you may use a thermoplastic resin for the prepreg in this invention. Examples of the thermoplastic resin that can be used include acrylic, polyester, polycarbonate, polypropylene, polyethylene, polystyrene, vinyl chloride, and polyamide resin. These may be used alone or in combination. In addition, a thermosetting resin composition obtained by mixing at least one thermosetting resin with at least one other resin (eg, other thermosetting resin, thermoplastic resin, etc.) is also preferably used. it can. In addition, the fiber reinforced resin composite material molded product and the fiber reinforced resin composite material / metal integrated molded product obtained by heating and pressing the prepreg and a metal such as aluminum, iron, and titanium are included. The fiber-reinforced composite material molded product is obtained by molding a fiber-reinforced composite material according to the application and shape, and can be used for parts such as aircraft and automobiles.

  A demolding method of this embodiment will be described. In the demolding method of the present invention, when a prepreg is heated and pressed by press molding to produce a fiber reinforced composite material molded product, the fiber reinforced composite material obtained by press molding is attached to the mold. It is a method of demolding. An apparatus for manufacturing a fiber-reinforced composite material molded article by heating and pressurizing a prepreg by press molding, including the demolding method of the present invention, is a press molding machine 1 having an upper mold 3 and a lower mold 4 as shown in FIG. Is used. 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. The press molding machine 1 includes cooling units 5 and 5.

  In this example, the manufacture of a fiber reinforced resin composite material molded product among the fiber reinforced composite material molded products will be described. First, the upper mold 3 and the lower mold 4 are heated to about 120 ° C. to 160 ° C. When a thermoplastic resin is used, the temperature is about 230 ° C to 290 ° C. The mold temperature is appropriately selected according to the curing temperature of the prepreg resin to be used. Next, the prepreg 2 of the carbon fiber-containing epoxy resin is disposed in the vicinity of 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 a fiber reinforced composite material and a metal integrated molded product instead of a fiber reinforced resin composite material molded product, a prepreg is disposed on a sheet-like metal such as iron, aluminum, or 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 1 MPa to 8 MPa. The pressing time is about 30 seconds to 180 seconds. The state at this time is shown in FIG.

  The prepreg 2 is cured by the pressurization and heating described above, and becomes a cured prepreg 21 (fiber-reinforced composite material molded product).

  In order to take out the manufactured cured prepreg 21, the upper mold 3 is raised. At this time, the cured prepreg 21 is attached to the surface of the upper mold 3. At this time, both the cured prepreg 21 and the upper mold 3 are at a high temperature, and the cured prepreg 21 cannot be removed from the upper mold 3 immediately.

  In order to remove the cured prepreg 21, the cooling gas guided by the cooling gas guide pipes 52 and 52 is blown from the cooling gas blowing portions 51 and 51 from the lateral direction of the cured prepreg 21. The cooling gas is preferably sprayed so that the cooling gas enters between the cured prepreg 21 and the upper mold 3.

  The cooling gas blowing parts 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 cured prepreg 21 from the side in a wide range.

  When the cooling gas is sprayed, the cured prepreg 21 and the press surface 31 (surface) of the upper mold 3 are instantaneously cooled, and the cured prepreg 21 can be removed.

  Here, the cooling gas is not particularly limited as long as the cured prepreg 21 and the press surface 31 can be cooled instantaneously, 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.

  The cured prepreg 21 cooled by the cooling gas is removed from the upper mold 3. The time required for demolding is about 5 to 60 seconds after the cooling gas is blown, and is extremely short. And the temperature of the metal mold | die after removing the cured prepreg 21 is about 110-150 degreeC. Moreover, when a thermoplastic resin is used, it is 220-280 degreeC. In the demolding method of the present invention, a cooling gas is used, but the temperature of the mold is reduced only by about −5 ° C. to −10 ° C.

  When the thermoplastic resin is impregnated instead of the thermosetting resin, for example, the preform is formed by heating the prepreg 2 in advance, and then heated and pressed (press-molded) to produce fibers. A reinforced composite material molded article can be produced. 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.

[About molds]
As described above, in the demolding method of the present invention, the cooling gas is sprayed between the prepreg adhering to the mold and the press surface, so that the adhering portion between the mold and the cured prepreg rapidly It has the feature that it can be cooled and taken out.

  The mold (upper mold 3 in the embodiment in FIG. 4) has a structure in which the cooling gas easily enters between the adhered cured prepreg 21 and the press surface 31.

  Specifically, as shown in FIG. 4 (perspective view A), the upper mold 3 has inclined portions 32 and 32 for facilitating introduction of the cooling gas into the center of the press surface 31. The inclined portions 32, 32 are arranged so that the cooling gas blown out from the cooling gas blowing portions 51, 51 can easily enter between the adhered cured prepreg 21 and the press surface 31. , 51 in the vicinity.

  The inclined portions 32 and 32 are preferably shaped so that the cooling gas spreads over the entire press surface 31. Specifically, the inclined portions 32 and 32 have a shape from the end of the upper mold 3 toward the center. It is preferable to have a shape that expands, and an example of such a shape is a trapezoidal shape as in the embodiment of FIG.

  The inclination angle of the inclined portions 32 and 32 is not particularly limited, but is usually about 10 to 45 degrees with respect to the installation surface of the upper mold.

  As shown in FIG. 5 (side view), FIG. 6 (perspective view B), and FIG. 7 (cross-sectional view), the upper mold 3 is hollowed out so that the opposite surface of the press surface 31 has a hollow portion 35. Preferably there is. In addition, a hollow part refers to the part by which the surface on the opposite side which faces the surface which a prepreg contacts in an upper metal mold | type or a lower metal mold | die was hollowed out (refer FIG. 6 etc.). The shape of the hollow portion may be a rectangular parallelepiped shape as shown in FIG. 6, or may be another shape. 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 a hollow portion can be provided in the mold. Naturally, as shown in FIGS. 1 to 7, the mold has a gripping part 33 and can exchange a mold having a necessary shape, but in the present invention, it has a hollow part 34. Thus, the weight is reduced by about 2/3 to 1/2 compared to an ingot-shaped mold that does not have the hollow portion 34, the mold can be easily replaced, and the temperature by heating This is preferable because the rise is faster.

  Moreover, the fiber-reinforced composite material molded product of the present invention can be produced not only in sheet form but also in other shapes.

Hereinafter, the effect of the present embodiment will be described.
[effect]
[1] A method for demolding a fiber-reinforced composite material molded article (cured prepreg 21) produced by press molding from a prepreg 2, between the upper mold 3 and the lower mold 4 after press molding. From the state in which the fiber-reinforced composite material molded product is sandwiched, the upper mold 3 and the lower mold 4 are separated from each other, and are attached to one press surface of the upper mold 3 and the lower mold 4. The method comprising blowing a cooling gas between the fiber reinforced composite material molded article and the attached press surface to remove the fiber reinforced composite material molded article from the mold 3 or 4. The cured prepreg 21 attached to the mold can be removed in a short time. Moreover, since the cured prepreg can be removed in a short time, the range of temperature rise and fall is small and energy consumption can be suppressed. Specifically, when the cooling gas is blown between the cured prepreg 21 and the press surface 31, the adhering portion is rapidly cooled, and the cured prepreg 21 is quickly removed. Can be demolded. If the cured prepreg 21 can be peeled off in a short time, the time for heating to a predetermined temperature (130 to 150 ° C.) for the next production is also shortened. Furthermore, since it is not necessary to lower the temperature of the entire mold, the temperature of the mold does not become too low (only decreases by about −5 ° C. to −10 ° C.), and it becomes easy to heat to a predetermined temperature. On the other hand, in the conventional water cooling, the mold temperature is lowered to 100 ° C. or lower, so that time and energy are required for reheating. That is, the present invention is extremely economical because not only the time is shortened but also the calorie consumption necessary for heating can be kept low. Furthermore, it is possible to prevent the fiber bundle from being deformed within the resin and to displace the fiber bundle, thereby improving the design.

[2] When the prepreg 2 includes a thermosetting resin or thermosetting resin composition and a carbon fiber base material, the resin cures at a predetermined temperature. Can be removed from the mold.

[3] In order to make it easier for the cooling gas to enter between the fiber-reinforced composite material molded article 21 and the press surface 31, the press surface 31 is provided with inclined portions 32, 32, If the inclined portions 32 and 32 are introduced toward the center of the press surface, more cooling gas can be easily taken in between the cured prepreg 21 and the press surface. Is extremely fast.

[4] If the inclined portions 32 and 32 have a shape that spreads from the end of the press surface 31 toward the center of the press surface 31, the gas introduced from the inclined portions 32 and 32 is attached. Since it can diffuse widely between the cured prepreg 21 and the press surface 31, the cured prepreg 21 can be peeled off at other times.

[5] If at least one of the upper mold 3 and the lower mold 4 is a hollow mold, after cooling and removing the cured prepreg 21, it can be quickly heated to a predetermined temperature. Therefore, there is little time loss in the manufacturing process, and the production amount of the cured prepreg 21 can be increased per unit time. Further, if the mold is made hollow, the weight becomes light and the mold can be easily exchanged. Such an effect cannot be achieved with a water-cooled mold.

[6] If the temperature of the cooling gas is −30 ° C. or more and −5 ° C. or less, the fiber-reinforced composite material molded product and the mold surface to which the fiber-reinforced composite material molded product is attached are instantaneously cooled. As a result, the mold can be removed in a short time.

1 Press molding machine 2 Prepreg 21 Hardened prepreg (Fiber-reinforced composite material molded product)
3 Upper mold 31 Press surface 32 Inclined part 33 Gripping part 34 Hollow part 4 Lower mold 5 Cooling part 51 Cooling gas blowing part 52 Cooling gas induction pipe 6 Upper mold heating part 7 Lower mold heating part

Claims (5)

A method of demolding a fiber-reinforced composite material molded product produced from a prepreg by press molding,
A step of separating the upper mold and the lower mold from each other from the state in which the fiber-reinforced composite material molded product is sandwiched between the upper mold and the lower mold after the press molding,
By blowing a cooling gas between the fiber reinforced composite material adhering to the press surface of the upper mold and the press surface adhering , the fiber reinforced composite material molded product is removed from the mold. A step of removing,
The said prepreg is a method containing a thermosetting resin or a thermosetting resin composition, and a carbon fiber base material. An inclined portion is provided at an end of the press surface so that the cooling gas can easily enter between the fiber-reinforced composite material molded product and the press surface, and the cooling gas is provided from the inclined portion to the center of the press surface. The method according to claim 1, wherein The method according to claim 2, wherein the inclined portion has a shape that extends from an end of the press surface toward a center. The method according to any one of claims 1 to 3, wherein at least one of the upper mold and the lower mold is a hollow mold. 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.