JP6971471B2 - Molding mold, manufacturing method of molded body, and molding method - Google Patents

Description

The present invention relates to a molding die, a method for manufacturing a molded body, and a molding method.

The fiber-reinforced composite material obtained from a prepreg obtained by impregnating reinforcing fibers such as carbon fiber with a thermosetting resin as a matrix resin in a semi-cured state is lightweight, yet has mechanical properties such as strength and rigidity, heat resistance, and corrosion resistance. It is excellent in such things. Therefore, fiber reinforced composite materials are used in various fields such as aircraft, automobiles, railways, ships, civil engineering and construction, and sporting goods.

The fiber-reinforced composite material is obtained by heating the prepreg to cure the semi-cured thermosetting resin contained in the prepreg. As a method of heating the thermosetting resin, there are a method of heating the thermosetting resin in an electric oven or the like, a method of irradiating the thermosetting resin with microwaves, and the like. Among them, the method of irradiating the thermosetting resin with microwaves can cure only the thermosetting resin contained in the prepreg in a short time, and therefore various studies have been conducted so far as a method for producing a fiber-reinforced composite material. ing.

When manufacturing a fiber-reinforced composite material, the fiber-reinforced composite material is molded into a predetermined shape by heating the prepreg while holding it in a desired shape using a molding die or the like to cure the thermosetting resin. ing.

As a method for producing a fiber-reinforced composite material having a predetermined shape while heating a prepreg using a molding die, for example, a resin transfer molding (RTM) method or the like is used. In the RTM method, for example, a reinforcing fiber is placed inside the molding die and sealed, and a thermosetting resin is injected under pressure into the reinforcing fiber inside the molding die, and then the molding die is heated. , A method of curing a thermosetting resin to form a fiber-reinforced composite material into a predetermined shape. When microwaves are applied to the curing of a thermosetting resin in a metal mold, the microwaves are reflected by the mold. Therefore, as the forming material of the molding die, a material having a high microwave transmittance and a low coefficient of thermal expansion, such as ceramics, is used.

For example, Patent Document 1 describes a mold base body made of a material that is substantially transparent to microwave radiation, and a mold tool surface having a microwave radiation absorbing material on or near the work surface. A molding mold for a composite material article containing the above is disclosed.

Patent Document 2 discloses a molding mold containing glass or ceramics and having a thermal effusivity of 1300 J / (m ² s ^1/2 K) or more and 3100 J / (m ² s ^1/2 K) or less. When a resin composite material is sandwiched between a pair of molding dies and press-molded, the resin composite material sandwiched between the molding dies is irradiated with microwaves. It suppresses the heat generated by heating the resin composite material by microwaves from escaping to the mold, traps the heat between the molds of the pair of molds, and heats and cures the thermosetting resin. There is.

Patent Document 3 discloses a method for producing a fiber-reinforced composite material in which a fiber-reinforced composite material is cured by using a plaster molding mold having good heat resistance and durability.

Special Table 2011-52144A Japanese Unexamined Patent Publication No. 2017-087550 International Publication No. 2011/040602

However, in the conventional molding die, when the molding die is porous, when the prepreg is brought into contact with the surface of the molding die and heated, the thermosetting resin contained in the prepreg is heated, so that the thermosetting resin is heated. The viscosity may decrease and the thermosetting resin may get inside the mold. Therefore, it may be difficult to remove the fiber-reinforced composite material obtained by heating the prepreg from the molding die.

One aspect of the present invention is to provide a molding die that can easily take out a molded body of an object to be molded.

The molding die according to one aspect of the present invention is a molding die for forming a molded body by molding a prepreg obtained by impregnating a reinforcing fiber with a matrix resin as an object to be molded, and is a space for accommodating the object to be molded. a pair of shaped bodies comprising a molding surface for forming the said pair of shaped bodies are arranged such that each of the molding surface facing the shaped body is a porous body formed contains gypsum The heat permeability of the molded product is 100 J / (m ² s ^1/2 K) or more and less than 1300 J / (m ² s ^1/2 K), and the molded surface has a coating layer containing silicone rubber. Is formed.

According to one aspect of the present invention, the molded body of the object to be molded can be easily taken out.

It is a perspective view which shows the state which sandwiched the fiber reinforced composite material in the molding mold which concerns on embodiment of this invention. It is a perspective view which shows the state which the molding mold which concerns on embodiment of this invention is opened. It is a front view of the molding die shown in FIG. It is a side view of the molding die shown in FIG. It is explanatory drawing of an example of the manufacturing method of a molded body. It is sectional drawing explaining the state which the thermosetting resin has entered into the inside of a model body. It is a perspective view which shows another example of a molding die.

Hereinafter, embodiments according to the present invention will be described. For ease of understanding, the scale of each member in the drawing may differ from the actual scale. In the present specification, a three-dimensional Cartesian coordinate system in the three-axis directions (X-axis direction, Y-axis direction, Z-axis direction) is used, the width direction of the molding die is the X-axis direction, the depth direction is the Y-axis direction, and the height is high. The (thickness) direction is the Z-axis direction. In the following description, the + Z-axis side in the height direction of the molding die may be referred to as an upper or upper part, and the −Z-axis side may be referred to as a lower part or a lower part.

<Molding mold>
The molding mold according to the embodiment of the present invention will be described. In this embodiment, a case where the object to be molded used in the molding die is a prepreg in which carbon fibers as reinforcing fibers are impregnated with a thermosetting resin as a matrix resin will be described.

FIG. 1 is a perspective view showing a state in which a fiber-reinforced composite material is sandwiched between molding molds according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a state in which a molding mold according to an embodiment of the present invention is open. 3A and 3B are front views of the molding die shown in FIG. 2, and FIG. 4 is a side view of the molding die shown in FIG. 2. As shown in FIGS. 1 to 4, the molding die 10 has a molded body 20 and a covering layer 30. Hereinafter, each configuration will be described.

(Modeled body)
The model 20 will be described. The model 20 is composed of a pair of the first model 20A and the second model 20B (hereinafter, the pair of the first model 20A and the second model 20B may be collectively referred to as the model 20). ). The first model 20A is arranged on the upper side, and the second model 20B is arranged on the lower side. The first modeled body 20A has a molded surface 21A, and the second modeled body 20B has a molded surface 21B. The first modeled body 20A and the second modeled body 20B are arranged along the Z-axis direction so that the molding surface 21A and the molding surface 21B face each other.

A space S for accommodating the prepreg 11 to be molded is formed between the molding surface 21A and the molding surface 21B. In the space S, when the first model 20A and the second model 20B are closed (the mold 10 is closed) and the prepreg 11 is sandwiched between the first model 20A and the second model 20B, the space S is formed. It is a space formed between the molding surface 21A and the molding surface 21B.

The prepreg 11 is housed in the space S in a state of being sandwiched between the molding surface 21A and the molding surface 21B via the covering layer 30. The prepreg 11 is a reinforced plastic molding material in which a cloth (preform) of carbon fiber, which is a reinforcing fiber, is impregnated with a thermosetting resin as a matrix resin to make the thermosetting resin semi-curable. Details of the prepreg 11 will be described later.

The model 20 is a porous body. The model 20 is formed by including gypsum. The model 20 has a porous structure formed of acicular crystals by containing gypsum.

The model 20 can be easily formed, for example, by placing a slurry in which powder of gypsum is dispersed in water in a mold container having a desired shape and drying the slurry. Further, since the modeled body 20 is formed to include gypsum, post-processing such as cutting the modeled body 20 or making a hole in the modeled body 20 can be easily performed. Therefore, the modeled body 20 is likely to be formed into a complicated shape. In addition, the gypsum has a specific density of 2.3 g / cm ³ , which is lighter than other heat-resistant inorganic materials (for example, iron has a specific density of 7.9 g / cm ^3). Easy to form large.

The water absorption rate of the model 20 is preferably more than 0% and 30% or less, and more preferably more than 0% and 10% or less. When the water absorption amount of the modeled body 20 is 31% or more, the strength of the modeled body 20 becomes low, and the modeled body 20 tends to lose its shape or have a large dimensional error. The water absorption rate means a value measured according to "JIS A 1110 (rough aggregate density and water absorption rate test method)".

Thermal effusivity of the shaped body 20, 100 J ^/ is preferably ^{(m 2 s 1/2} K) than 1300J ^/ less than ^{(m 2 s 1/2} K), more preferably 500J ^{/ (m} 2 ^{s 1 / 2} K) or more and 1000 J / (m ² s ^1/2 K) or less.

When the thermal effusivity of the model 20 is within the above range, heat transfer is suppressed, so that the heat containment effect can be exhibited.

As for the thermal effusivity, the thermal effusivity is b [J / (m ² · s ^1/2 · K)], the thermal conductivity is κ [W / (m · K)], and the density is ρ [kg / m]. ³ ]), where the specific heat capacity is C [J / (kg · K)], it can be obtained from the following formula (1).
b = (κ × ρ × C) ^1/2 ... (1)

The thermal conductivity of the model 20 can be determined by using a steady-state heat flow meter method (HFM method). The hot plate temperature of the thermal conductivity measuring device is 20 ° C. and 30 ° C. The specific heat capacity is determined using the value at room temperature.

The model 20 may contain other heat-resistant inorganic materials as long as it can form a porous structure. As the heat-resistant inorganic material, ceramics, glass, cork, cement and the like can be used. These may be contained alone or may be contained in plurality.

(Coating layer)
The covering layer 30 will be described. The coating layer 30 can be formed of silicone rubber. Silicone rubber has the property of transmitting microwaves and has the property of having low adhesion to thermosetting resins. In addition, silicone rubber has excellent airtightness and chemical resistance.

Silicone rubber is a rubber-like silicone resin having a siloxane bond (Si—O bond) as a molecular skeleton. As the silicone rubber, for example, methyl silicone rubber, vinyl / methyl silicone rubber, dimethyl silicone rubber, fluorosilicone rubber, methylphenyl silicone rubber, vinyl silicone rubber and the like can be used. Specific examples of the commercially available product include KE-1308 (manufactured by Shin-Etsu Chemical Co., Ltd.). These can be used alone or in admixture of two or more.

Silicone rubber is obtained by curing (crosslinking) a silicone rubber composition. When the silicone rubber composition is a liquid silicone rubber composition containing an organopolysiloxane having self-fluidity at room temperature (usually 25 ° C ± 10 ° C) as a main component (base polymer), silicone can be added by adding a curing agent. Rubber is obtained.

The curing agent has the property of curing the main agent when heated together with the main agent. As the curing agent, any curing agent for silicone rubber, which is a thermosetting resin, can be used. As the curing agent, for example, an addition reaction curing agent, an organic peroxide curing agent, or the like can be used. Specifically, CE62 (manufactured by Momentive) or the like can be used as a commercially available product. These can be used alone or in combination of two or more.

The blending amount of the curing agent is appropriately set according to the type and blending amount of the main agent, and is appropriately set according to the molding conditions, characteristics, etc. within the range in which the curing agent is usually used.

The silicone rubber composition may contain various additives in addition to the above components, if necessary. Examples of the additive include a reinforcing material, a filler, a softening agent, an antiaging agent, a stabilizer, an adhesion accelerator, a leveling agent, a defoaming agent, a plasticizer, an inorganic filler, a tackifying resin, and a usable time extending agent. , Antioxidants, UV absorbers, Antihydrogenants, Antifungal agents, Thickeners, Plasticizers, Coloring agents such as pigments and the like may be used in combination.

As a method for preparing the silicone rubber composition, either a one-component type or a two-component type can be adopted. The one-component preparation method refers to a method in which all the ingredients are mixed in advance, stored in a sealed container, and then cured by the humidity in the air after construction. The two-component preparation method refers to a method in which a curing agent and a solvent, and if necessary, components such as a filler and a plasticizer are mixed, and the main agent and the curing agent are mixed before construction.

When the silicone rubber composition is a one-component type, all the components are premixed, so that if water is present in the silicone rubber composition, curing may proceed during storage. Therefore, it is preferable to dehydrate the components containing water by dehydrating and drying them in advance and then adding them or reducing the pressure in a mixed state.

When the silicone rubber composition is a two-component type, it is necessary to add a curing agent to the main agent, so even if the silicone rubber composition contains some water, there is little concern about the progress of curing (gelling). If long-term storage stability is required, dehydration drying is preferred.

The coating layer 30 is formed by applying the silicone rubber composition before the polymerization reaction to the molded surface 21 of the model 20 and curing it at a predetermined temperature to form the coating layer 30 on the molded surface 21.

The thickness of the coating layer 30 is preferably 0.1 mm or more and 1 mm or less, and more preferably 0.1 mm or more and 0.5 mm or less. When the thickness is within this range, the fiber-reinforced composite material obtained by molding the prepreg 11 can be easily demolded, and the dimensional error of the object to be molded is small. In this embodiment, the thickness means the length of the layer in the direction perpendicular to the contact surface of the covering layer 30. Further, the thickness of the coating layer 30 may be, for example, the average value of the thicknesses of these measurement points when measured at several points (for example, about 3 points) at an arbitrary place in the cross section of the covering layer 30.

(Manufacturing method of molding mold)
Next, a method for manufacturing the molding die 10 will be described. By supplying a slurry in which powder of gypsum is dispersed in water to a mold container having a desired shape and drying it, a model 20 composed of a pair of the first model 20A and the second model 20B is manufactured. do. After that, the silicone rubber composition is applied to the molded surface 21A of the first modeled body 20A and the molded surface 21B of the second modeled body 20B.

The method of applying the silicone rubber composition is not particularly limited. As a method for applying the silicone rubber composition, for example, a gravure coat, a roll coat, a spin coat, a reverse coat, a bar coat, a screen coat, a blade coat, an air knife coat, dipping, a dispensing and the like can be used.

After applying the silicone rubber composition to the molded surface 21A and the molded surface 21B, the silicone rubber composition is cured by heating the molded body 20 coated with the silicone rubber composition at a predetermined temperature, and the molded body 20 is molded. A molding die 10 having a coating layer 30 formed on the surface 21A and the molding surface 21B is manufactured.

The heating temperature of the model 20 coated with the silicone rubber composition may be any temperature as long as the silicone rubber composition can be cured, and is, for example, 20 to 150 ° C.

<Manufacturing method of fiber reinforced composite material>
Next, a manufacturing method for manufacturing a fiber-reinforced composite material, which is a molded body, from a prepreg, which is a molded product, will be described using the molding die 10. As a method for producing a fiber-reinforced composite material from a prepreg using the molding die 10, for example, an RTM method, a vacuum resin impregnation method (VaRTM: Vacuum assisted Resin Transfer Molding) method, or the like can be used. In this embodiment, a case where a prepreg is produced from a preform using an RTM method to produce a fiber-reinforced composite material will be described.

FIG. 5 is an explanatory diagram showing an example of a method for manufacturing a fiber-reinforced composite material. As shown in FIG. 5, the carbon fiber cloth (preform) 111 constituting the prepreg 11 was arranged on the covering layer 30 of the molding surface 21B of the second model 20B. After that, the first modeled body 20A and the second modeled body 20B are closed (the molding die 10 is closed) and sandwiched between the molding surfaces 21A of the first modeled body 20A (molding, the space S of the molding die 10 is filled with space S). In a sealed state, the thermosetting resin under pressure is injected into the preform 111 in the space S, whereby the molding surface 21A of the first molding body 20A and the molding surface 21B of the second molding body 20B are injected. The prepreg 11 is formed in a state of being sandwiched between the molding surface 21A and the molding surface 21B.

Then, the molding die 10 and the prepreg 11 are irradiated with microwaves to cure the semi-cured thermosetting resin contained in the prepreg 11. As a result, the fiber-reinforced composite material 40 containing the cured product of the thermosetting resin is formed in the reinforcing fibers. The fiber-reinforced composite material 40 is molded into a predetermined shape corresponding to the shapes of the molding surface 21A and the molding surface 21B.

The wavelength of the microwave irradiating the prepreg 11 is preferably 300 MHz or more and 3000 MHz or less, and preferably 500 MHz or more and 2500 MHz or less. When the wavelength of the microwave is within the above range, when the prepreg 11 is irradiated with the microwave, the semi-cured thermosetting resin contained in the prepreg can be heated almost uniformly.

After forming the fiber-reinforced composite material 40 in the space S of the molding die 10, the first molding body 20A and the second molding body 20B are opened (the molding die 10 is opened), so that the molding die 10 forms a predetermined shape. The fiber-reinforced composite material 40 is obtained.

By irradiating the prepreg 11 with microwaves, heat is generated from the carbon fibers constituting the preform 111. The heat generated from the carbon fibers accelerates the curing of the thermosetting resin, and accelerates the curing of the thermosetting resin. As a result, the thermosetting resin in the semi-cured state contained in the prepreg 11 cures in a shorter time than the thermosetting resin containing no reinforcing fibers. The semi-cured thermosetting resin contained in the prepreg 11 should be cured, for example, with a heating time of 1/36 or less of the curing time (recommended curing time) recommended for the thermosetting resin containing no carbon fiber. Can be done. Therefore, if the molding method using the molding die 10 is used, the prepreg 11 can be cured in a shorter time to produce the fiber-reinforced composite material 40.

(Prepreg)
The prepreg 11 used for the molding die 10 will be described in detail. The prepreg 11 contains carbon fibers and a semi-cured thermosetting resin impregnated with the carbon fibers. The prepreg 11 is a reinforced plastic molding material in which carbon fibers are impregnated with a thermosetting resin and heated or allowed to stand at room temperature to be in a semi-cured state.

The carbon fiber is contained in a state where the surface is covered with a thermosetting resin. Carbon fibers have the property of absorbing microwaves and generating heat when irradiated with microwaves. In the present embodiment, carbon fiber is used as the reinforcing fiber, but other reinforcing fibers may include cellulose fiber or a fibrous reinforcing material such as polyester fiber, Kevlar fiber, and silicon carbide fiber. Further, instead of the carbon fiber, any one or more of the fibrous reinforcing materials may be used.

The thermosetting resin is a matrix resin impregnated with carbon fibers.

Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, vinyl ester resins, polyimide resins, bismaleimide resins, urethane resins, amino resins such as melamine, urea and phenol, and silicone resins. Fluorescent resin and the like can be mentioned. Only one type of these may be used alone, or two or more types may be used in combination. Among these, epoxy resins and the like are preferable because they can be cured in a shorter time.

Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, flexible epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, brominated epoxy resin, and glycidyl ester. Examples thereof include a type epoxy resin, a glycidylamine type epoxy resin, a hydride-in type epoxy resin, an isocyanurate type epoxy resin, and an acrylic acid-modified epoxy resin. As the epoxy resin, these may be used alone or in combination of two or more.

The thermosetting resin can contain a curing agent. Examples of the curing agent include a carboxylic acid-based curing agent having a carboxyl group or a carboxylic acid anhydride group (acid anhydride-based curing agent); an amine having an amino group, an amide group, a ketoimine group, an imidazole group, a dicyandiamide group and the like. A system-based curing agent; or a phenol-based curing agent having a phenol group such as phenol novolak; or the like can be used.

Specific examples of the acid anhydride-based curing agent include succinic anhydride, maleic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic acid anhydride, methyltetrahydrophthalic acid anhydride, and methylnadic acid anhydride. Hexahydrohydride phthalic acid, methylhexahydrohydride phthalic acid, 1,2-cyclohexanedicarboxylic acid anhydride, 4-methylcyclohexane-1,2-dicarboxylic acid anhydride, 3,4,5,6-tetrahydrophthalic acid anhydride, Examples thereof include 2,3-naphthalenedicarboxylic acid anhydride. These can be used alone or in combination of two or more.

Specific examples of amine-based curing agents include aliphatic polyamines such as triethylenetetraamine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, and 2-methylpentamethylenediamine; isophoronediamine, 1,3-. Alicyclic polyamines such as bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norbornenediamine, 1,2-diaminocyclohexane; N-aminoethylpiperazine, 1,4-bis (2-amino-2-methylpropyl). ) Piperazine-type polyamines such as piperazine; diethyltoluenediamine, dimethylthiotoludiamine, 4,4'-diamino-3,3'-diethyldiphenylmethane, bis (methylthio) toluenediamine, diaminodiphenylmethane, m-phenylenediamine, diaminodiphenyl Examples include aromatic polyamines such as sulfone, diethyltoluenediamine, trimethylenebis (4-aminobenzoate) and polytetramethylene oxide-di-p-aminobenzoate. Moreover, as a commercial product, jER cure ST-11 (trade name, manufactured by Mitsubishi Chemical Corporation) and the like can be mentioned. These can be used alone or in combination of two or more.

Specific examples of the phenol-based curing agent refer to monomers, oligomers, and polymers having a phenolic hydroxyl group, for example, phenol novolac resin, cresol novolak resin, phenol aralkyl (including phenylene and biphenylene skeleton) resin, naphthol aralkyl resin, Examples thereof include triphenol methane resin and dicyclopentadiene type phenol resin. These can be used alone or in combination of two or more.

Although the prepreg 11 uses a thermosetting resin as the matrix resin, a thermoplastic resin can also be used. The thermoplastic resin is not particularly limited, but is limited to polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, styrene / acrylonitrile copolymer, styrene / butadiene / acrylonitrile copolymer, polyethylene, ethylene / vinyl acetate copolymer, and the like. Polypropylene, polyacetal, polymethylmethacrylate, modified acrylic resin, cellulose acetate, polycarbonate, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyurethane, ethylene trifluoride chloride, ethylene tetrafluoride / propylene hexafluoride copolymer, A tetrafluoride ethylene / perfluoroalkoxyethylene copolymer, vinylidene fluoride, or the like can be used. Only one type of these may be used alone, or two or more types may be used in combination.

In the molding die 10 configured as described above, the covering layer 30 is formed on the molding surface 21 of the molded body 20. Since the model 20 is a porous body, as shown in FIG. 6, when the prepreg 11 is brought into direct contact with the surface of the porous body 20, the thermosetting resin 112 contained in the prepreg 11 is formed. Invade the inside of the body. In particular, when the thermosetting resin 112 contained in the prepreg 11 is heated, the viscosity of the thermosetting resin 112 decreases, so that the thermosetting resin 112 easily penetrates into the modeled body 20. When the thermosetting resin 112 in the prepreg 11 is cured while the thermosetting resin 112 has penetrated into the model 20, the fiber-reinforced composite material obtained by curing the thermosetting resin 112 is the model 20. It becomes difficult to remove from. In the present embodiment, since the molding die 10 forms the coating layer 30 on the molding surface 21 of the molding body 20, the thermosetting resin contained in the prepreg 11 penetrates into the inside from the surface of the molding body 20 and bites into the inside. Can be suppressed. Further, since the coating layer 30 is formed to contain silicone rubber, it has a property of having low adhesion to a thermosetting resin. Therefore, the molding die 10 can easily remove the fiber-reinforced composite material 40 (see FIG. 5) formed on the surface of the coating layer 30.

Further, as described above, since the molding die 10 includes the plaster to form the molded body 20, it is easy to form the molding surfaces 21A and 21B into a complicated shape. Since the molding die 10 can easily remove the fiber-reinforced composite material 40 while maintaining the shapes corresponding to the molding surfaces 21A and 21B, the fiber-reinforced composite material 40 having a complicated shape (see FIG. 5) can be easily removed. Can be molded. Therefore, even when the molded surfaces 21A and 21B of the modeled body 20 are provided with a pattern such as a plurality of holes or irregularities, the shape of the pattern formed on the fiber-reinforced composite material 40 (see FIG. 5) is maintained. Can be stably taken out from the molding die 10.

Further, since the coating layer 30 has a property of transmitting microwaves, the thermosetting resin can be cured in a short time by irradiating the molding die 10 with microwaves. Therefore, the molding die 10 can easily mold the fiber-reinforced composite material 40 (see FIG. 5) in a short time.

Further, since the silicone rubber contained in the coating layer 30 has airtightness and chemical resistance, the molding die 10 can have excellent durability.

Since the molding die 10 can reduce the water absorption rate of the modeled body 20 to 0% or more and 30% or less, the strength of the modeled body 20 is high, and the shape loss and dimensional error of the modeled body 20 can be reduced. Therefore, the molding die 10 can have high shape stability.

Mold 10, the thermal effusivity of the shaped body 20, it is possible to less than ^{100J / (m 2 s 1/2 K} ) than ^{1300J / (m 2 s 1/2 K} ), heat is externally in shaped bodies 20 It can suppress the release and exert the heat containment effect. By confining heat in the prepreg 11, the semi-cured thermosetting resin contained in the prepreg 11 can be cured in a shorter time.

Since the molding die 10 has the above-mentioned characteristics, it can be suitably used as a mold for forming vehicle parts such as automobiles and railways, aircraft parts, and the like. By using the molding die 10 according to the present embodiment for manufacturing a molded body used for a vehicle, an aircraft, or the like, vehicle parts and aircraft parts can be manufactured in a short time.

In the present embodiment, the pair of the first modeled body 20A and the second modeled body 20B constituting the modeled body 20 are integrally molded, but may be configured by combining a plurality of modeled members. For example, as shown in FIG. 7, the pair of first modeling body 20A and second modeling body 20B has two first modeling members 20A-1 and 20A-2 and second modeling members 20B-1 and 20B, respectively. It may be configured by combining with -2.

Hereinafter, embodiments will be described in more detail with reference to Examples and Comparative Examples, but the embodiments are not limited to these Examples.

<Example 1>
[Example 1-1]
(Making a molding mold)
100 g of grilled gypsum (manufactured by Wako Pure Chemical Industries, Ltd.) and 70 mL of distilled water were mixed and mixed for 1 minute and 30 seconds to prepare a slurry. After vacuum defoaming the slurry for 3 minutes, the vacuum defoamed slurry is poured into a silicone rubber mold (inner diameter 40 mm), and is composed of a pair of first and second shaped bodies including a disk-shaped gypsum having a diameter of 40 mm. The body was made. After allowing to stand for 2 hours, the silicone rubber mold was removed from the disk-shaped model, and the model was placed in an electric oven at 40 ° C. and dried for about 12 hours. A silicone composition obtained by mixing a silicone rubber (TSE350, manufactured by Momentive) and a curing agent (CE62, manufactured by Momentive) is formed on the surface of the molded surface of the pair of first and second molded bodies. It was applied to a size of about 0.5 mm, placed in an electric oven at 40 ° C., and cured for about 12 hours. As a result, a molding die was obtained in which the surfaces of the molding surfaces of the pair of first moldings and the second molding were covered with a coating layer made of silicone rubber.
(Application of thermosetting resin composition)
A bisphenol A type epoxy resin (jER827 (registered trademark), manufactured by Mitsubishi Chemical Corporation) is used as the main agent, and an amine compound curing agent (jER Cure ST-11 (registered trademark)) is used as the curing agent. Mitsubishi Chemical Co., Ltd.) was used. A small amount of a thermosetting resin composition mixed with a main agent and a curing agent was applied onto a moldable silicone rubber. Then, the mold coated with the thermosetting resin composition was placed in an electric oven at 120 ° C. and heated for 3 hours to cure the thermosetting resin composition. The recommended curing condition of the curing agent is to heat at 80 ° C. for 3 hours in addition to heating at 23 ° C. for 24 hours.

[Example 1-2]
Except that in Example 1-1, the main agent used in the thermosetting resin composition was changed from the bisphenol A type epoxy resin to the bisphenol F type epoxy resin (jER806 (registered trademark), manufactured by Mitsubishi Chemical Corporation). , The same procedure as in Example 1-1 was carried out.

[Example 1-3]
In Example 1-1, the curing agent used in the thermosetting resin composition was changed from an amine-based compound curing agent to an acid anhydride-based compound curing agent (jER Cure LV11 (registered trademark), manufactured by Mitsubishi Chemical Corporation). It was carried out in the same manner as in Example 1-1 except that it was changed. The recommended curing condition of the curing agent is to heat at 80 ° C. for 3 hours in addition to heating at 23 ° C. for 24 hours.

[Example 1-4]
In Example 1-1, the main agent used in the thermosetting resin composition was changed from a bisphenol A type epoxy resin to a bisphenol F type epoxy resin (jER806, manufactured by Mitsubishi Chemical Corporation). The curing agent used in the thermosetting resin composition was changed from an amine-based compound curing agent to an acid anhydride-based compound curing agent (jER Cure LV11 (registered trademark), manufactured by Mitsubishi Chemical Corporation). Other than that, the procedure was the same as in Example 1-1.

[Comparative Example 1-1]
In Example 1-1, a molded body whose surface was not coated with silicone rubber was prepared as a molding die. Then, when the vacuum-defoamed slurry is poured into a silicone rubber mold (inner diameter 40 mm) to produce a disk-shaped model having a diameter of 40 mm, a silicone rubber having a diameter of 16 mm and a thickness of 2 mm is previously placed on the bottom of the silicone rubber mold. In the same manner as in Example 1-1, except that a disk-shaped shaped body having a concave groove having a diameter of 16 mm and a thickness of 2 mm was produced.

[Comparative Example 1-2]
In Comparative Example 1-1, Comparative Example 1 except that the main agent used in the thermosetting resin composition was changed from the bisphenol A type epoxy resin to the bisphenol F type epoxy resin (jER806, manufactured by Mitsubishi Chemical Corporation). It was done in the same manner as -1.

[Comparative Example 1-3]
In Comparative Example 1-1, the main agent used in the thermosetting resin composition was a bisphenol A type epoxy resin (jER827 (registered trademark), manufactured by Mitsubishi Chemical Corporation) and an acid anhydride compound curing agent (jER Cure LV11). The same method as in Comparative Example 1-1 was used except that the thermosetting resin composition (registered trademark), manufactured by Mitsubishi Chemical Corporation) was mixed.

[Comparative Example 1-4]
In Comparative Example 1-1, a bisphenol F type epoxy resin (jER806 (registered trademark), manufactured by Mitsubishi Chemical Corporation) used in the thermosetting resin composition and a curing agent of an acid anhydride compound (jER Cure LV11 (registered trademark)). ) And (manufactured by Mitsubishi Chemical Corporation) were mixed, and the same method as in Comparative Example 1-1 was used.

[examination]
In the molding molds of Examples 1-1 to 1-4, the epoxy resin composition applied to the surface of the molding mold is cured without being absorbed by the molded product, and is easily removed from the surface of the silicone rubber in the state of the cured product. Was made. On the other hand, in the molding molds of Comparative Examples 1-1 to 1-4, a part of the epoxy resin composition flowed from the surface of the modeled body to the inside and was cured, so that the cured product of the epoxy resin composition was cured from the modeled body. Could not be removed.

Therefore, by forming the coating layer made of the silicone rubber composition on the contact surface of the modeled body with the epoxy resin composition, the epoxy resin composition applied to the surface of the coated layer does not bite into the inside of the modeled body. Could be cured on the surface of. As a result, it was confirmed that the cured product of the epoxy resin composition could be easily removed.

<Example 2>
[Preparation of model and covering layer]
(Making a model)
In Example 1-1, the same procedure as in Example 1-1 was carried out except that the slurry was placed in a silicone rubber mold having a diameter of 60 mm to prepare a model having a thickness of 15 mm.
(Preparation of coating layer)
Using the same silicone rubber as in Example 1-1 as the coating layer, a sheet made of silicone rubber having a thickness of 0.5 mm and a square shape of 40 mm was prepared.
(Measurement of thermal conductivity)
As a result of measuring these thermal conductivity by the steady method (HC-110, manufactured by Eiko Seiki), the thermal conductivity of the modeled body is 0.36 W / m · K, and the coating layer is 0.23 W / m · K. It was K.
(Measurement of thermal effusivity)
Using the following formula (1), the thermal conductivity κ of the model is 0.36 W / m · K, the density ρ of the model is 1250 kg / m ³ , and the specific heat capacity C of the model is 1050 J / (kg · K). , The thermal effusivity b [J / (m ² · s ^1/2 · K)] of the modeled body was calculated. As a result, the thermal effusivity of the model was 690 J / (m ² · s ^1/2 · K). Using the following formula (1), the thermal conductivity κ of the coating layer is 0.23 W / m · K, the density ρ of the coating layer is 970 kg / m ³ , and the specific heat capacity C of the coating layer is 1600 J / (kg · K). , The thermal effusivity b of the coating layer was calculated. As a result, the thermal effusivity b of the coating layer was 600 J / (m ² · s ^1/2 · K). The thermal conductivity was measured at hot plate temperatures of 20 ° C. and 30 ° C. using a steady method. Moreover, the value at room temperature was used for the specific heat capacity.
b = (κ × ρ × C) ^1/2 ... (1)

Thermal effusivity of the shaped body was higher than the thermal effusivity of silicone rubber, thermal effusivity of the shaped body and silicone ^{rubber, 100J / (m 2 s 1/2} K) than 1300J ^{/ (m} 2 ^{s 1} It was less than ^{/ 2K).} Therefore, if a silicone rubber coating layer is formed on the modeled body, the heat applied from the outside can be contained when the semi-cured thermosetting resin in the prepreg supplied to the inside of the modeled body is cured. It was confirmed that the curing time of the semi-cured thermosetting resin in the prepreg can be shortened.

<Example 3>
[Example 3-1]
(Preparation of thermosetting resin in semi-cured state)
Using the VaRTM method, a 20-layer carbon fiber cloth (model CO6343, manufactured by Toray Industries, Inc.), a bisphenol F type epoxy resin (jER806 (registered trademark), manufactured by Mitsubishi Chemical Industries, Ltd.) and an amine compound curing agent (jER carrier) are used. The epoxy resin composition mixed with ST11 (registered trademark), manufactured by Mitsubishi Chemical Industries, Ltd.) was impregnated and allowed to stand at room temperature for 8 hours to make the epoxy resin composition semi-cured in a 40 mm square. The recommended curing condition of the curing agent is to heat at 80 ° C. for 3 hours in addition to heating at 23 ° C. for 24 hours.
(Curing of thermosetting resin using microwave)
Next, one side of the above-mentioned model formed in Example 2-1 was covered with a silicone rubber having a thickness of 0.5 mm to prepare a one-molded mold. The prepreg is sandwiched between a pair of molding dies, and the prepreg is irradiated with microwaves having a frequency of 2.45 GHz and an output of 50 W for 5 minutes to heat and cure the thermosetting resin contained in the prepreg. Obtained the material.

When the end face of the prepreg after microwave irradiation was measured by infrared thermography, the end face of the prepreg was heated to 100 to 130 ° C., and the surface of the mold in contact with the prepreg was 70 ° C.

Therefore, in Example 3-1 it was confirmed that when the prepreg was irradiated with microwaves, heat transfer to the molding die was suppressed and heat was confined in the space of the molding die. When the surface temperature of the fiber-reinforced composite material was measured using a radiation thermometer, the surface temperature of the fiber-reinforced composite material was measured by separating the first model and the second model immediately after stopping the microwave irradiation and immediately forming the model. It was heated to 132 ° C. The thermosetting resin, which was in a semi-cured state of the prepreg before the irradiation with microwaves, was cured and could be easily separated from the mold.

Therefore, by sandwiching the prepreg between a pair of shaped bodies having a coating layer made of silicone rubber formed on the molded surface and irradiating the prepreg with microwaves, the thermosetting resin can be cured in a shorter time than the recommended curing time of the curing agent. It was confirmed that it can be cured and the obtained fiber-reinforced composite material can be easily separated.

As described above, the embodiments have been described, but the above embodiments are presented as examples, and the present invention is not limited to the above embodiments. The above-described embodiment can be implemented in various other embodiments, and various combinations, omissions, replacements, changes, and the like can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

10 Mold 11 Prepreg 20 Model 20A 1st model 20B 2nd model 21A, 21B Molding surface 30 Coating layer S space

Claims (7)

A prepreg obtained by impregnating a matrix resin into reinforcing fibers to a mold for forming a molded article by molding as an object to be molded,
It has a pair of shaped objects having a molded surface that forms a space for accommodating the object to be molded.
The pair of shaped objects are arranged so that their molding surfaces face each other.
The modeled body is a porous body formed by containing gypsum.
The thermal effusivity of the shaped body is a 100 J ^/ less than ^{(m 2 s 1/2} K) than ^{1300J / (m 2 s 1/2 K} ),
A molding die, characterized in that a coating layer containing silicone rubber is formed on the molding surface. The molding mold according to claim 1, wherein the water absorption rate of the molded product is more than 0% and 30% or less. The molding die according to claim 1 or 2, wherein the thickness of the coating layer is 0.1 mm or more and 1 mm or less. The molding die according to any one of claims 1 to 3, wherein the modeled body is formed by combining a plurality of modeling members. Was impregnated with a matrix resin to reinforcing fiber prepreg A method of manufacturing the mold for forming the molded to shaped bodies as an object to be molded,
The pair of shaped bodies having a molded surface forming a space for accommodating the object to be molded is a porous body formed by containing gypsum.
The thermal effusivity of the shaped body is a 100 J ^/ less than ^{(m 2 s 1/2} K) than ^{1300J / (m 2 s 1/2 K} ),
Before KiNaru form surface, and forming a coating layer containing a silicone rubber, a method of manufacturing the mold. It is a molding method in which a prepreg in which reinforcing fibers are impregnated with a matrix resin is molded as an object to be molded.
Microwave to a prepreg in which reinforcing fibers are impregnated with a matrix resin, which is arranged in a space formed by a pair of molding surfaces of a pair of moldings provided in the molding mold according to any one of claims 1 to 4. A molding method comprising a step of heating the matrix resin contained in the prepreg by irradiating the prepreg. When the matrix resin is a thermosetting resin and contains a curing agent,
The molding method according to claim 6 , wherein the thermosetting resin contained in the prepreg cures faster than the recommended curing time of the thermosetting resin.

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