JP2018176570A - Method for manufacturing fiber-reinforced plastic molded product, and demolding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing, by press-forming, fiber-reinforced plastic molded products in a short time, efficiently and with low energy.SOLUTION: A method for manufacturing fiber-reinforced plastic molded products from prepreg by press-forming includes a step to prepare an upper mold and a lower mold, wherein at least one of the upper mold and the lower mold includes a plastic layer on a surface contacting prepreg, a step to place prepreg on the lower mold, a step to form a fiber-reinforced plastic molded product by pressing the prepreg using the upper mold and the lower mold, a step to separate the upper mold and the lower mold from a state where the fiber-reinforced plastic molded product is sandwiched between the upper mold and the lower mold, and a step to remove the fiber-reinforced plastic molded product from the mold by spraying cooling gas on the fiber-reinforced plastic molded product and the plastic layer to which the fiber-reinforced plastic molded product sticks.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method of manufacturing a fiber reinforced resin molded product by press molding, and a method of demolding from a mold.

  A fiber-reinforced resin molded product composed of a resin such as epoxy and a fiber bundle can be manufactured 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, autoclave molding, vacuum bag molding, RTM method, and press molding have conventionally been used for such production.

  Among them, the press molding method is considered to be desirable from the viewpoint of obtaining a high-quality fiber-reinforced resin molded product with high productivity.

International Publication No. 2013/081058 pamphlet

  However, unlike a metal material, a prepreg is likely to adhere to a mold when it is press-molded. When the adhered molded prepreg is removed from the mold (demolded), it is necessary to cool the mold, and the productivity per unit time decreases due to the cooling time. Conventionally, water cooling or oil cooling has been used to cool the entire mold, but it takes time to cool, and when producing fiber reinforced resin molded articles continuously after cooling, the cooled mold It had to be heated to the original temperature, and it took a long time to continuously produce a fiber-reinforced resin molded article.

  An object of the present invention is to provide a method for producing a fiber-reinforced resin molded product by press molding efficiently in a short time and with low energy.

  The present inventors arrived at the present invention as a result of extensive research. That is, one of the present invention is a step of preparing an upper mold and a lower mold, and at least one of the upper mold and the lower mold is provided with a resin layer on the surface in contact with the prepreg. Forming a fiber reinforced resin molded product by disposing a prepreg on the lower mold, pressing the prepreg with the upper mold and the lower mold, and forming the upper mold A step of separating the upper mold and the lower mold from each other while the fiber reinforced resin molded article is sandwiched between the lower mold and the lower mold, the fiber reinforced resin molded article, and the fiber reinforced resin A method of manufacturing a fiber reinforced resin molded article from a prepreg by press molding, comprising the steps of: blowing a cooling gas onto the resin layer to which the molded article adheres; and removing the fiber reinforced resin molded article from the mold is there.

  In the manufacturing method of the present invention, since the molded prepreg (fiber-reinforced resin molded product) attached to the mold can be removed in a short time, productivity improvement can be expected. In addition, since it is not necessary to cool the mold to the same temperature as the fiber reinforced resin molded product to be demolded, the range of temperature rise and fall is small, and energy consumption can be suppressed. Furthermore, a three-dimensional fiber reinforced resin molded product can also be produced.

FIG. 1 is a view when a prepreg is disposed in the lower mold. FIG. 2 is a diagram showing a state in which the upper mold is lowered and 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 adheres to the lower mold. FIG. 4 is a cross-sectional view at the time of press-molding a prepreg. FIG. 4A is a view showing the upper mold being lowered to the prepreg disposed in the lower mold. FIG. 4B is a view showing a state in which the prepreg is press-formed between the convex portion of the upper mold and the concave portion of the lower mold. As shown in FIG. 4 (c), a cooling gas is blown to the resin layer provided on the lower mold when the upper mold and the lower mold are separated, and to the molded prepreg (fiber-reinforced resin molded article) to remove the resin layer. It is a figure which shows the state which is being shape | molded.

  In the present specification, a fiber-reinforced resin molded product is formed into a predetermined shape by heating and pressing a prepreg which is a composite of a fiber base and a thermosetting resin, a thermoplastic resin, or a resin composition. Are obtained by Therefore, in the present 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.

  In addition, a prepreg is a composite of a thermosetting resin or a thermoplastic resin on a fiber substrate such as carbon fiber or glass fiber, and as a specific example, a thermosetting resin or a fibrous resin on the fiber substrate What apply | coats (impregnates) a thermoplastic resin, and makes it dry and heat and semi-hardened is mentioned.

  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 a resin used as a material of a prepreg, although either a thermosetting resin or a thermoplastic resin can be used, the thermosetting resin hardened | cured at about 100-150 degreeC is preferable. As a thermosetting resin, an epoxy resin, a vinyl ester resin, unsaturated polyester resin, a polyurethane resin, a phenol resin etc. are mentioned, These can be used combining.

  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. . Specifically, acrylic resin, polyester resin, polycarbonate resin, polypropylene resin, polyethylene resin, polystyrene resin, vinyl chloride resin, polyamide resin can be mentioned. These may be used alone or in combination of two or more.

  In the present specification, the fiber-reinforced resin molded article is a fiber-reinforced resin / metal integrated molded article joined by heating and pressing a prepreg made of a fiber base and resin and a metal such as aluminum, iron or titanium. Shall be included.

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

  In the present invention, press molding is performed by being sandwiched between both molds using an upper mold and a lower mold. The upper mold and the lower mold can have a predetermined shape to form a fiber reinforced resin molded article. For example, the pressing side of the upper and lower molds can have flat surfaces. By doing this, it is possible to form a flat fiber-reinforced resin molded article. As another aspect, on the pressing side of the upper mold and the lower mold, a convex portion is provided on one side, and a concave portion corresponding to the convex portion on the other side (the convex portion can be inserted) is provided. Can. By doing so, since the prepreg is sandwiched between the convex portion and the concave portion, the fiber-reinforced resin molded product obtained can have a three-dimensional shape.

  At least one of the upper and lower molds used in the present invention has a resin layer on the surface in contact with the prepreg. The resin layer may be provided in any of the upper and lower molds, or may be provided in both the upper and lower molds. When the upper mold and the lower mold are provided with projections or recesses, the resin layer can be provided on the projections or recesses.

  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. or more than the melting point of the resin of the prepreg 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 for the mold can contain a component that enhances the heat radiation effect. The component that enhances the heat radiation effect is not particularly limited, but carbon fibers can be included from the viewpoint of easy handling and high heat radiation. That is, the resin layer is preferably composed of a composite material of carbon fiber and resin. When a resin layer is comprised from a composite material, the method of using carbon fiber as a core material of a resin layer is mentioned as one specific aspect.

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

  The pressure at the time of pressurization is also not particularly limited, but is usually 1 MPa to 8 MPa.

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

  Specifically, by cooling the fiber reinforced resin molded article and the resin layer disposed in the mold, the fiber reinforced resin molded article attached to either the upper mold or the lower mold is demolded. 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 an apparatus for producing air at about -20 ° C., “Jet cooler (trade name)” manufactured by Nippon Seiki Co., Ltd. and the like can be mentioned.

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

  Furthermore, by providing the resin layer, even when the pressing surface of the mold has a convex portion and a concave portion, the entire resin layer is cooled by transmitting the cooling also to the portion where the cooling gas is not sprayed. And it becomes easy to demold.

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

  The fiber-reinforced resin molded product thus obtained is obtained by molding a fiber-reinforced resin according to the application and shape, and can be used for parts of aircraft, automobiles and the like.

  The invention will now be described in detail by way of examples. The present invention is not limited to the examples, and design changes and the like can be appropriately made within the range 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 to carry out the manufacturing method of the present embodiment is provided with 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 located 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 also includes cooling gas blowout portions 51, 51 for guiding the cooling gas to a wide range, and cooling gas guiding pipes 52, 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, And a lower mold resin layer 42 containing carbon fiber (see FIG. 4A). The protrusion 31 can enter the recess 41. The upper mold resin layer 32 and the lower mold resin layer 42 each use a cyanate resin having a thickness of 1 cm and a melting point of 400.degree.

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

  Then, the upper mold 3 is moved downward, and the prepreg 2 is sandwiched between the upper mold 3 and the lower mold 4 and pressurized. 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.

  The prepreg 2 is molded by the above-described heating and pressing, 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 adheres 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 have a high temperature, and the fiber-reinforced resin molded product 21 can not be immediately removed from the lower mold 4.

  In order to demold the fiber reinforced resin molded product 21, the cooling gas induced by the cooling gas induction pipes 52, 52 is transferred from the cooling gas blowout part 51, 51 to the fiber reinforced resin molded product 21 and the lower mold resin layer 42. Spray from the side towards the

  It is preferable that the cooling gas blowout portions 51, 51 have a blowout port having a shape closer to a flat shape than a round shape so that the fiber reinforced resin molded product 21 falls in a wide range from the side.

  When the cooling gas is blown, 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 entire lower mold resin layer 42 is cooled by spraying the cooling gas on a part of the lower mold resin layer 42.

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

  The time taken to remove the fiber-reinforced resin molded product 21 is about 10 seconds after spraying the cooling gas, which is an extremely short time.

  As described above, in the method for producing a fiber-reinforced resin molded article according to the present invention, the fiber is sprayed by blowing a cooling gas toward the fiber-reinforced resin molded article attached to the mold and the resin layer provided on the mold surface. The portion adhering to the reinforced resin molded product has a feature that can be rapidly cooled and taken out.

  When a thermoplastic resin is impregnated instead of a thermosetting resin, for example, a preform is produced by heating the prepreg 2 in advance to produce a preform, and then heating and pressing (press molding) to form a fiber. Reinforced resin molded articles can be produced. The demolding method at this time is the same as that described above, but the heating temperature is preferably set to a temperature higher than that of the case where a thermosetting resin is used.

[Release process]
Next, demolding in the method of manufacturing the fiber-reinforced resin molded product 21 will be described in detail using a cross-sectional view. 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 disposed on the lower mold 4 provided with the recess 41. The upper mold 3 having the convex portion 31 is lowered relative to the lower mold 4, and the prepreg 2 is sandwiched between the upper mold 3 and the lower mold 4 (FIG. 4 (b)). 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 (the fiber-reinforced resin molded product 21) adheres to the lower mold 4. The lower mold 4 provided with the fiber reinforced resin molded product 21 and the lower mold resin layer 42 adhering thereto is cooled, and the fiber reinforced resin molded product 21 is released from the mold (FIG. 4 (c)). The cooling is performed by blowing a cooling gas from cooling gas blowout sections 51, 51 guided to the cooling gas guiding pipes 52, 52 to a part of the fiber reinforced resin molded product 21 and the lower mold resin layer 42. Even when a portion of lower mold resin layer 42 is cooled, the mold central portion (near part B) shown in FIG. 4 where the cooling gas is difficult to contact is also cooled by transmission, and the lower mold resin The entire layer 42 is cooled, allowing for demolding. Without the lower mold resin layer 42, it takes time to cool the surface of the metal, and the time required for demolding becomes longer.
Although the case where the fiber reinforced resin molded product 21 is attached to the lower mold 4 has been described in the present embodiment, when the fiber reinforced resin molded product 21 adheres to the upper mold 3, the molded prepreg 21 (fiber reinforced resin molded product); A cooling gas is blown to the upper mold resin layer 32 to release the mold.

  As shown in FIG. 4, in the upper mold 3 and the lower mold 4, the opposite sides of the upper mold resin layer 32 and the lower mold resin layer 42 correspond to the upper mold hollow portion 33 and the lower mold hollow, respectively. It is preferable to be hollowed out to have a part 43. The upper mold hollow portion 33 and the lower mold hollow portion 43 mean portions of the upper mold 3 or the lower mold 4 in which the surface opposite to the surface in contact with the prepreg 2 is hollowed out. The shape of the upper mold hollow portion 33 and the lower mold hollow portion 43 may be rectangular or may be another shape. Further, the size of the hollow portion is not particularly limited, but can be 50% to 80% with respect to the volume of the entire mold. In addition to making a mold by hollowing out a metal ingot, it is also possible to combine plate-like metals and join them to make a mold. A mold produced by combining plate materials in this manner is also within the scope of the present invention. In the case of combining plate materials, it is possible to provide a large hollow portion while suppressing waste.

  In the case of this embodiment, since the water cooling of the mold is not performed, it is not necessary to arrange a water cooling pipe in the mold, so the hollow portions 33 and 43 can be provided in the mold. The mold has a holding part if necessary, and as a matter of course the mold having the necessary shape can be replaced, but in the present invention, the hollow parts 33 and 43 can be obtained by having the hollow parts 33 and 43. The weight is reduced by about 2/3 to 1/2 as compared to a non-ingot-like mold, and the mold can be easily replaced, and furthermore, the temperature rise due to heating is quickened. preferable.

  Further, the fiber-reinforced resin molded product of the present invention can produce not only three-dimensional sheets but also other shapes.

The effects of this embodiment will be described below.
[effect]
[1] A process of preparing an upper mold and a lower mold, wherein at least one of the upper mold and the lower mold is provided with a resin layer on a surface in contact with a prepreg; Forming a fiber reinforced resin molded product by disposing a prepreg on the upper surface, pressing the prepreg with the upper mold and the lower mold, the upper mold and the lower mold, and And separating the upper mold and the lower mold from each other, attaching the fiber reinforced resin molded article, and the fiber reinforced resin molded article from a state in which the fiber reinforced resin molded article is sandwiched therebetween. The method of manufacturing a fiber reinforced resin molded article from a prepreg by press molding comprising blowing a cooling gas onto the resin layer and removing the fiber reinforced resin molded article from the mold efficiently in a short time , Yet 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 recessed 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 fibers, the heat dissipation of the resin layer is enhanced, and the resin layer is instantaneously cooled by a cooling gas, for a short time It becomes possible to release the mold.
[4] In the method according to any one of the above [1] to [3], when the resin layer is formed 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 the above [1] to [4], in the case where the prepreg contains an epoxy resin and a carbon fiber base material, a widely used epoxy fiber reinforced resin An article can be obtained.
[6] In the method according to any one of the above [1] to [5], even if the temperature of the cooling gas is -30 ° C. or more and -5 ° C. or less, removal of the mold in a short time is possible It is.
[7] 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 after press molding, and At least one of the mold and the lower mold blows a cooling gas on the step of providing a resin layer on the press surface, the fiber reinforced resin molded article, and the resin layer to which the fiber reinforced resin molded article adheres Thus, the method for removing a press-formed 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 with low energy efficiently in a short time. Can be removed from the mold.

1 Press Forming Machine 2 Prepreg 21 Fiber Reinforced Resin Molded Article (Molded Prepreg)
DESCRIPTION OF SYMBOLS 3 upper mold 31 convex part 32 upper mold resin layer 33 upper mold hollow part 4 lower mold 41 recessed part 42 lower mold resin layer 43 lower mold hollow part 51 cooling gas blowing part 52 cooling gas induction pipe 6 upper metal Mold heating part 7 Lower mold heating part

Claims (7)

Providing an upper mold and a lower mold, wherein at least one of the upper mold and the lower mold includes a resin layer on a surface in contact with the prepreg;
Placing a prepreg on the lower mold;
Forming a fiber-reinforced resin molded product by pressing the prepreg with the upper mold and the lower mold;
Separating the upper mold and the lower mold from each other while the fiber-reinforced resin molded product is sandwiched between the upper mold and the lower mold;
Pressing from a prepreg, including the step of removing the fiber reinforced resin molded product from the mold by spraying a cooling gas onto the fiber reinforced resin molded product and the resin layer to which the fiber reinforced resin molded product is attached A method of producing a fiber-reinforced resin molded article 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 product has a three-dimensional shape.   The method according to claim 1, wherein the resin layer is made of a composite material containing carbon fibers.   The method according to any one of claims 1 to 3, wherein the resin layer is made of cyanate resin or polycarbonate resin.   The method according to any one of claims 1 to 4, wherein the prepreg comprises an epoxy resin and a carbon fiber base material.   The method according to any one of claims 1 to 5, wherein the temperature of the cooling gas is -30 ° C to -5 ° C. In 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 after press molding, the upper mold and the lower mold are separated. Providing a resin layer on the press surface of at least one of the lower molds;
Press forming including the step of removing the fiber reinforced resin molded product from the mold by spraying a cooling gas onto the fiber reinforced resin molded product and the resin layer to which the fiber reinforced resin molded product is attached Method of removing fiber reinforced resin molded products.