JP6701674B2 - Method for producing fiber-reinforced plastic molded product - Google Patents

Description

  The present invention relates to a method for producing a fiber-reinforced plastic molded product.

Molded products (FRP molded products) of composite materials (fiber-reinforced plastic: FRP) in which reinforcing fibers such as organic fibers, carbon fibers, and glass fibers are dispersed in a resin matrix are excellent in strength and rigidity and are lightweight. Therefore, it is widely used for various purposes such as building materials, automobiles, aircrafts, sporting goods and the like.
In the FRP molded product, the mechanical properties greatly change depending on the dispersion state of the reinforcing fibers in the resin matrix. For example, when the reinforcing fibers in the resin matrix are oriented, the strength against tensile in the fiber direction is increased.

The application of a papermaking method has been studied as a method for producing FRP.
For example, a method of obtaining FRP by a papermaking method using a papermaking material containing a fiber filler and a resin has been proposed (see Patent Document 1).
The papermaking method is a papermaking technique.By applying this method, it is easy to uniformly disperse the reinforcing fibers in the resin matrix, and the reinforcing fibers can easily have directionality. The characteristics are improved.

JP, 2005-81296, A

In recent years, the use of FRP molded products has expanded, and the demand for FRP has increased. Along with this, the FRP molded product has various demands such as further improvement of mechanical properties such as strength and expression of other properties such as heat conduction, electromagnetic wave shielding properties, heat dissipation properties, etc., as compared with conventional ones.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a novel method for producing a fiber-reinforced plastic molded product.

  The present inventors, while investigating the improvement of the characteristics of the molded product, a layer using a molding material (resin composition) containing a resin or the like in a prepreg (paper prepreg) using FRP obtained by a papermaking method. It was found that a new layer (intermediate molded article portion) in which the paper-making material and the resin composition are mixed together is attempted to be laminated, and a unique performance as a molded article can be expressed, and the present invention is completed. I arrived.

  That is, the method for producing a fiber-reinforced plastic molded product of the present invention is a method for producing a paper prepreg by drying a molded body produced by removing a dispersion medium from a papermaking material containing a first resin, fibers and a dispersion medium. In the step (i) of obtaining, and in the state where the resin composition containing the second resin is brought into contact with the papermaking prepreg, the papermaking prepreg and the resin composition are molded to form a papermaking prepreg molded body part or a resin. A composition-molded body part, and a fiber-reinforced plastic molded product provided with an intermediate molded body part adjacent to at least one of these molded body parts and containing the components in the paper-making material and the components in the resin composition. It has a step (ii) of obtaining.

In the step (ii), it is preferable to perform the molding so that the intermediate molded body portion is adjacent to the papermaking prepreg molded body portion and the resin composition molded body portion, respectively.
Alternatively, in the step (ii), it is preferable to perform the molding so that the intermediate molded body part is adjacent to one molded body part of the papermaking prepreg molded body part and the resin composition molded body part.

According to the manufacturing method of the present invention, a novel fiber-reinforced plastic molded product can be manufactured.
For example, according to the present invention, it is possible to manufacture an FRP molded product having higher mechanical properties.

It is a figure which shows the cross section of the FRP molded product manufactured by the manufacturing method of 1st Embodiment. 1 is a photograph showing a cross section of an FRP molded product 10, the left half is an incident light image of an optical microscope, and the right half is an image of a polarizing filter over an optical microscope. It is a schematic diagram which shows the orientation state of the fiber contained in the 1st molded body part 12 and the 3rd molded body part 14. It is a figure which shows the cross section of the FRP molded product manufactured by the manufacturing method of 2nd Embodiment. It is a figure which shows the cross section of the FRP molded article manufactured by the manufacturing method of 3rd Embodiment. It is a figure for demonstrating the three-point bending test method in an Example.

(Method for manufacturing fiber-reinforced plastic molded products)
The method for producing a fiber-reinforced plastic molded product (FRP molded product) of the present embodiment includes a step (i) of obtaining the following paper-making prepreg and a step (ii) of obtaining a fiber-reinforced plastic molded product.
Step (i): A step of drying a shaped body produced by removing a dispersion medium from a papermaking material containing a first resin, fibers and a dispersion medium to obtain a papermaking prepreg Step (ii): the papermaking prepreg In the state of contacting the resin composition containing the second resin, the papermaking prepreg and the resin composition are molded, and a papermaking prepreg molded body part or a resin composition molded body part, and at least one of these To obtain a fiber-reinforced plastic molded article having an intermediate molded body portion adjacent to the molded body portion and containing the component in the papermaking material and the component in the resin composition.

  Hereinafter, the papermaking material and the resin composition used in the present embodiment will be described.

-Papermaking material The papermaking material used in the present embodiment contains a resin (first resin), fibers, and a dispersion medium.

..Resin (first resin)
Examples of the resin (first resin) used for the papermaking material include thermosetting resins and thermoplastic resins.
Examples of the thermosetting resin in the first resin include phenol resin, epoxy resin, bismaleimide resin, melamine resin, urethane resin and the like.
Examples of the thermoplastic resin in the first resin include polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyamide, polyether ketone, polyether ether ketone, polysulfone, polyphenylene sulfide, and the like.
Among these, from the viewpoint of mechanical strength or chemical resistance, thermosetting resins are preferable, phenol resins, epoxy resins, bismaleimide resins are more preferable, and phenol resins are particularly preferable because they can be used for a wide range of applications. preferable.

Examples of the phenolic resin include novolac type phenolic resins such as phenol novolac resin, cresol novolac resin, bisphenol A novolac resin, aryl alkylene type novolac resin; unmodified resole phenolic resin, tung oil, linseed oil, walnut oil, etc. Resol type phenolic resins such as oil-modified resole phenolic resins may be mentioned.
Among these, the novolac type phenol resin is preferable in terms of cost and moldability.

The weight average molecular weight of the phenol resin is not particularly limited, but a weight average molecular weight of 1,000 to 15,000 is preferable.
If the weight average molecular weight of the phenol resin is less than the lower limit of the above preferred range, the viscosity of the resin may be too low and molding may be difficult, and if it exceeds the upper limit of the above preferred range, the melt viscosity of the resin is Since it becomes high, the moldability may decrease.
The weight average molecular weight of the phenol resin can be measured by gel permeation chromatography (GPC) and specified as a polystyrene-equivalent weight molecular weight.

Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type, bisphenol F type and bisphenol AD type; novolak type epoxy resins such as phenol novolac type and cresol novolac type; brominated bisphenol A type, brominated phenol novolac type Brominated epoxy resin; biphenyl type epoxy resin; naphthalene type epoxy resin; tris(hydroxyphenyl)methane type epoxy resin and the like.
Among these, bisphenol type epoxy resins and novolac type epoxy resins are preferable from the viewpoint of high fluidity and moldability.
Among these, bisphenol A type epoxy resin, phenol novolac type epoxy resin and cresol novolac type epoxy resin having a relatively low molecular weight are more preferable. From the viewpoint of heat resistance, a phenol novolac type epoxy resin and a cresol novolac type epoxy resin are more preferable, and a tris(hydroxyphenyl)methane type epoxy resin is particularly preferable.

The bismaleimide resin is not particularly limited as long as it is a resin having maleimide groups at both ends of the molecular chain, but a resin having a benzene ring is preferable, and for example, a resin represented by the following general formula (1) can be used. ..
However, the bismaleimide resin may have maleimide groups at both ends of the molecular chain.

[In formula, R< ¹ >-R< ⁴ > represents a C1-C4 hydrocarbon group which may have a substituent, or a hydrogen atom. R ⁵ represents a divalent organic group. ]

Here, the organic group is a hydrocarbon group which may contain atoms other than carbon atoms, and examples of the atoms other than carbon atoms include O, S, N and the like.
R ⁵ preferably has a main chain structure in which a methylene group, an aromatic ring, and an ether bond (—O—) are bonded in any order, and has a substituent and/or a side chain on the main chain. Good. The total number of methylene groups, aromatic rings and ether bonds contained in the main chain structure is 15 or less. Examples of the above-mentioned substituent or side chain include a hydrocarbon group having 3 or less carbon atoms, a maleimide group, a phenylene group, and the like.

  Specific examples of the bismaleimide resin include N,N′-(4,4′-diphenylmethane)bismaleimide, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, 2,2-bis[4 -(4-maleimidophenoxy)phenyl]propane, m-phenylene bismaleimide, p-phenylene bismaleimide, 4-methyl-1,3-phenylene bismaleimide, N,N'-ethylenedimaleimide, N,N'-hexa Methylene dimaleimide etc. are mentioned.

The 1st resin may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the first resin in the papermaking material is preferably 10 to 60% by volume, more preferably 20 to 55% by volume, based on the total solid content (100% by volume) of the papermaking material (excluding the polymer flocculant). %, and more preferably 30 to 55% by volume.
When the content of the first resin is within the above-mentioned preferable range, it is easy to obtain a molded product having a good appearance and less uneven resin distribution when the papermaking material is molded.
Further, when the content of the first resin is not less than the lower limit value of the preferable range described above, the strength of the paper-prepared prepreg molded body portion is easily secured. On the other hand, when it is at most the upper limit of the above preferred range, the handleability of the papermaking material will be better.

.. Fiber As the fiber used for the paper-making material, organic fiber, inorganic fiber, metal fiber and the like can be mentioned.
For example, as the fiber, polyamide fiber, aramid fiber, polyimide fiber, polyparaphenylenebenzoxazole fiber, polyarylate fiber, ultra high molecular weight polyethylene fiber, synthetic fiber such as high strength polypropylene fiber, acrylic fiber, phenol fiber, carbon fiber, Examples thereof include glass fiber, ceramic fiber, rock wool, potassium titanate fiber, basalt fiber, stainless fiber, steel fiber, aluminum fiber, copper fiber, brass fiber, and bronze fiber.

Among these, the present embodiment is particularly useful when aramid fiber, carbon fiber or glass fiber is used as the fiber.
When aramid fiber or carbon fiber is used as the fiber, the mechanical strength of the FRP molded product can be further increased and the weight of the molded product can be further reduced.
When glass fiber is used as the fiber, the uniformity of the papermaking material per unit volume is further increased, and the formability of the papermaking material is particularly good. Furthermore, since the uniformity of the papermaking material is increased, the uniformity of internal stress in the formed FRP molded product is improved, and the waviness of the molded product is further suppressed. In addition, the wear resistance of the molded product due to high load is further enhanced.

  The aramid resin that constitutes the aramid fiber may have either a meta-type structure or a para-type structure.

Specific examples of the carbon fibers include high-strength carbon fibers having a tensile strength of 3500 MPa or more, carbon fibers having a high elastic modulus of 230 GPa or more, and the like.
The carbon fiber may be either a polyacrylonitrile (PAN)-based carbon fiber or a pitch-based carbon fiber, but a PAN-based carbon fiber is preferable from the viewpoint of further enhancing the strength of the molded product. In addition, pitch-based carbon fibers are preferable from the viewpoint of imparting thermal conductivity to the surface of the molded product.

Examples of the glass constituting the glass fiber include E glass, C glass, A glass, S glass, D glass, NE glass, T glass, and H glass.
Among these, E-glass, T-glass, and S-glass are preferable because the fiber can be made highly elastic and the thermal expansion coefficient thereof can be easily reduced.

The cross-sectional shape of the fiber is not particularly limited, and may be any shape such as a circular shape, an elliptic shape, or another substantially circular shape, a triangular shape, a polygonal shape such as a quadrangular shape, a hexagonal shape, a flat shape, or a star shape. Among these, the substantially circular shape and the flat shape are preferable. When the cross section of the fiber has such a shape, the smoothness of the surface of the FRP molded product is further enhanced. Further, the handleability at the time of molding the papermaking material is improved, and the moldability is further improved.
As the fibers, chopped strands are preferably used from the viewpoint of improving strength such as bending strength and impact resistance. Further, as the fiber, from the viewpoint of improving the yield, it is preferable to use fibers beaten by a mechanical shearing force such as a beater or a homogenizer, or fibrillated fibers (pulp) together with chopped strands. Since the pulp has a large fiber surface area and has a physically high ability to capture the resin, it becomes easy to chemically act with the polymer flocculant by using this pulp.

The fibers are preferably long fibers. In particular, long fibers, when used in combination with a thermosetting resin, are excellent in heat resistance and exhibit high specific strength, high corrosion resistance and vibration damping property. Further, the use of long fibers is superior to the case of using short fibers in that high mechanical strength, particularly mechanical strength at high temperature, creep resistance and the like are imparted.
The long fibers referred to herein are fibers having a length of 1 mm or more (preferably 1 to 50 mm), and the short fibers are fibers having a length of 0.1 to 0.5 mm.

The average length of the fibers is appropriately determined according to the required characteristics, and for example, the lower limit value is preferably 1 mm or more, more preferably 3 mm or more, and the upper limit value is preferably 100 mm or less, more preferably 50 mm or less, and 10 mm. The following is more preferable, and 8 mm or less is particularly preferable.
When the average length of the fibers is equal to or more than the preferable lower limit value, the characteristics of the fibers are likely to be exhibited. When it is at most the preferable upper limit value, the moldability will be easily secured.
Above all, the average length of the fibers is preferably 1 mm or more, particularly 3 mm or more and 8 mm or less, because the characteristics of the fibers are exhibited and the molding processability is easily secured.

The average diameter of the fibers is preferably 1 to 100 μm, more preferably 5 to 80 μm.
When the average diameter of the fibers is equal to or more than the preferable lower limit value, the molded product is likely to have rigidity. When it is at most the preferable upper limit value, the moldability will be easily secured.

The term "molding workability" refers to the surface smoothness or demoldability of an FRP molded product.
The length and diameter of the fiber can be measured by observing the FRP with an electron microscope.

The fibers may be used alone or in combination of two or more.
The content of fibers in the papermaking material is preferably 20 to 80% by volume, more preferably 30 to 70% by volume, based on the total solid content (100% by volume) of the papermaking material (excluding the polymer flocculant). It is preferably 35 to 60% by volume.
When the content of the fibers is within the preferable range described above, the mechanical properties of the FRP molded product can be more efficiently enhanced. Further, when the content of the fibers is equal to or more than the preferable lower limit value, impact resistance and the like are easily improved. When it is at most the above preferable upper limit value, it becomes easy to maintain lightness and workability.

As the fibers, those which have been subjected to a surface treatment in advance may be used for the purpose of improving dispersibility in the paper-making material, enhancing adhesion with the resin, and the like.
Examples of the surface treatment method for such fibers include coupling agent treatment, oxidation treatment, ozone treatment, plasma treatment, corona treatment, and blast treatment. Of these, fibers treated with a coupling agent are preferable.

.. Dispersion medium The dispersion medium used in the papermaking material is not particularly limited, but those having a boiling point of 50 to 200[deg.] C. are preferable from the viewpoints of difficulty in volatilization, easy removal of solvent, and the like.
Examples of the dispersion medium include water; alcohols such as ethanol, 1-propanol, 1-butanol, and ethylene glycol; ketones such as acetone, methyl ethyl ketone, 2-heptanone, and cyclohexanone; ethyl acetate, butyl acetate, methyl acetoacetate, etc. Ethers such as tetrahydrofuran, isopropyl ether, dioxane, furfural, and the like.
Among these, water is particularly preferable because it is inexpensive, has a low environmental load, is highly safe, and is easy to handle.
As the dispersion medium, one type may be used alone, or two or more types may be used in combination.
The content of the dispersion medium in the papermaking material is preferably 0.05 to 3% by mass, more preferably 0.1 to 3% by mass based on the total solid content (100% by mass) of the papermaking material (excluding the polymer flocculant). It is 2% by mass.
The solid content concentration of the papermaking material (excluding the polymer flocculant) is preferably 0.2 to 2.0% by mass, more preferably 0.3 to 1.0% by mass.

-Arbitrary component The papermaking material may contain components (arbitrary component) other than the resin (first resin), the fiber and the dispersion medium.
Examples of the optional component in the papermaking material include a surface treatment agent, a powdery substance having an ion exchange ability, a polymer flocculant, and a filler powder excluding the above fibers.

.. Surface treatment agent As the surface treatment agent, known ones can be mentioned, and various coupling agents can be used depending on the type of fiber or resin.
Examples of the coupling agent include a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, and a silicone oil coupling agent.
Among these, the silane coupling agent is preferable because the adhesion between the fiber and the resin can be further enhanced.
Examples of the silane coupling agent include epoxy silane coupling agent, cationic silane coupling agent, amino silane coupling agent, vinyl silane coupling agent, mercapto silane coupling agent, methacryl silane coupling agent, chlorosilane coupling agent, Examples include acrylic silane coupling agents.

...Powdered substance having ion exchange ability The papermaking material may further contain a powdered substance having ion exchange ability. By having this powdery substance together, the fiber length of the fiber is maintained long, the aggregate of the fiber and the resin is efficiently prepared with a high yield, and the blending ratio of the fiber and the resin is wide. Can be adjusted to. Therefore, it is possible to more efficiently obtain an FRP having an excellent balance between the characteristics of the fiber and the characteristics of the resin, depending on the required characteristics.

Examples of the powdery substance having an ion-exchange ability include intercalation compounds such as clay minerals, flake-shaped silica fine particles, hydrotalcites, fluorine teniolite, and swelling synthetic mica.
The clay mineral is not particularly limited whether it is a natural product or a synthetic product, and examples thereof include smectite, halloysite, kanemite, kenyaite, zirconium phosphate, and titanium phosphate.
The hydrotalcites are not particularly limited as long as they have an ion exchange capacity, and examples thereof include hydrotalcite and hydrotalcite-like substances.
The fluorine teniolite is not particularly limited as long as it has an ion exchange ability, and examples thereof include lithium type fluorine teniolite and sodium type fluorine teniolite.
The swelling synthetic mica is not particularly limited as long as it has an ion exchange capacity, and examples thereof include sodium tetrasilicon fluorine mica and lithium tetrasilicon fluorine.
Among these, clay minerals are more preferable, smectites are more preferable because they are present from natural products to synthetic products and have a wide range of selection.

The smectite is not particularly limited as long as it has ion exchange ability, and examples thereof include montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, stevensite and the like.
Although montmorillonite is a hydrous silicate of aluminum, it may be bentonite which contains montmorillonite as a main component and also contains minerals such as quartz, mica, feldspar, and zeolite. Synthetic smectite containing a small amount of impurities is preferable when it is used for coloring or when it is necessary to care about impurities.

Examples of the powdery substance having an ion exchange ability include Kunipia (bentonite) manufactured by Kunimine Industry Co., Ltd., Smecton SA (synthetic saponite), Sunlabry (scale silica fine particles) manufactured by AGC SII Tech Co., Ltd. Somasif (swelling synthetic mica), Lucentite (synthetic smectite) manufactured by Chemical Co., Ltd., and hydrotalcite STABACE HT-1 (hydrotalcite) manufactured by Sakai Chemical Industry Co., Ltd. are commercially available. However, it is not limited to these.
As the powdery substance having an ion exchange ability, one type may be used alone, or two or more types may be used in combination.

... Polymer Flocculant The papermaking material may further contain a polymer flocculant. By having this polymer coagulant together, the fibers and the resin can be more flocculated.
The polymer coagulant is not particularly limited by ionicity and the like, and a cationic polymer coagulant, an anionic polymer coagulant, a nonionic polymer coagulant, an amphoteric polymer coagulant, etc. can be used. ..
Examples of the polymer flocculant include cationic polyacrylamide, anionic polyacrylamide, Hoffman polyacrylamide, mannic polyacrylamide, amphoteric copolymerized polyacrylamide, cationized starch, amphoteric starch, polyethylene oxide and the like.
The polymer structure and molecular weight, the amount of functional groups such as hydroxyl groups and ionic groups, etc. in the polymer flocculant are not particularly limited regardless of the required characteristics.
Examples of the polymer flocculant include polyethylene oxide manufactured by Wako Pure Chemical Industries, Ltd., Kanto Chemical Co., Ltd. or Sumitomo Seika Chemicals; and a cationic PAM manufactured by Harima Kasei Co., Ltd. Fix, anionic PAM, Hermide B-15, amphoteric PAM, Hermide RB-300, and cationized starch SC-5 manufactured by Sanwa Starch Industry Co., Ltd. are commercially available. It is not limited.
The polymer flocculants may be used alone or in combination of two or more.

... Filler powder excluding the fibers The paper-making material may further contain a filler powder excluding the fibers for the purpose of adjusting the properties.
Examples of such filler powder include inorganic powder and metal powder.
As the inorganic powder, for example, oxides such as titanium oxide, alumina, silica, zirconia and magnesium oxide, nitrides such as boron nitride, aluminum nitride and silicon nitride, sulfides such as barium sulfate, iron sulfate and copper sulfate. , Hydroxides such as aluminum hydroxide and magnesium hydroxide, minerals such as kaolinite, talc, natural mica and synthetic mica, carbides such as silicon carbide, or coupling depending on the properties required for these Examples thereof include those that have been surface-treated with agents and the like.
The metal powder may be a metal powder composed of a single metal or an alloy powder composed of a plurality of metals. Examples of the metal that constitutes the metal powder include aluminum, silver, copper, magnesium, iron, chromium, nickel, titanium, zinc, tin, molybdenum, and tungsten.

  Paper-making materials include stabilizers such as antioxidants and ultraviolet absorbers, mold release agents, plasticizers, flame retardants, resin curing catalysts and curing accelerators, in addition to the above-mentioned components, depending on required properties. , Colorant, paper strength improver such as dry paper strength improver, wet paper strength improver, yield improver, drainage improver, size fixer, defoamer, rosin sizing agent for acidic papermaking, neutral papermaking Use rosin-based sizing agents, alkyl ketene dimer-based sizing agents, alkenylsuccinic anhydride-based sizing agents, sizing agents such as specially modified rosin-based sizing agents, sulfuric acid bands, coagulants such as aluminum chloride, polyaluminum chloride, etc. You can

-Regarding the resin composition The resin composition used in the present embodiment contains a resin (second resin).

..Resin (second resin)
Examples of the resin (second resin) used in the resin composition include curable resins such as thermosetting resins, photocurable resins, reactive curable resins, and anaerobic curable resins. Among these, the thermosetting resin is preferable because the mechanical properties such as the coefficient of linear expansion and the elastic modulus after curing are further enhanced.
Examples of the thermosetting resin in the second resin include phenol resin, epoxy resin, bismaleimide resin, melamine resin, urethane resin and the like. Among these, from the viewpoint of mechanical strength or chemical resistance, thermosetting resins are preferable, phenol resins, epoxy resins, bismaleimide resins are more preferable, and phenol resins are particularly preferable because they can be used for a wide range of applications. preferable.
The description of the phenol resin, epoxy resin, and bismaleimide resin is the same as the above description.

  The combination of the first resin and the second resin is not particularly limited, but it is preferable to use the same type of resin from the viewpoint of easy mixing of the paper-making material and the resin composition during heating. For example, it is preferable that the first resin and the second resin are the same type of resin selected from a phenol resin, an epoxy resin, and a bismaleimide resin.

The second resin may be used alone or in combination of two or more.
The content of the second resin in the resin composition is preferably 5 to 60% by mass, more preferably 20 to 55% by mass, and further preferably 30% with respect to the total solid content (100% by mass) of the resin composition. Is about 50% by mass.
When the content of the second resin is equal to or more than the lower limit value of the preferable range described above, the strength of the resin composition molded body portion is easily secured. On the other hand, when it is at most the upper limit value of the above preferred range, the handleability of the resin composition will be better.

..Arbitrary component The resin composition may contain a component (arbitrary component) other than the resin (second resin).
Examples of the optional components in the resin composition include fibers, curing agents, curing aids, fillers, release agents, coupling agents, flame retardants, and coloring agents such as carbon black.

... Fiber The resin composition may further contain fibers. Examples of the fibers that the resin composition may contain include the same fibers as those contained in the papermaking material.
The average length of the fibers that the resin composition may contain is appropriately determined according to the required properties, and is preferably 500 μm or less, more preferably 10 to 300 μm. When the average length of the fibers is equal to or less than the above preferable upper limit value, moldability is easily secured. When it is at least the above preferred lower limit value, the characteristics of the fiber are likely to be exhibited.
The average diameter of the fibers that the resin composition may contain is preferably from 5 to 20 μm, more preferably from 6 to 18 μm, even more preferably from 7 to 16 μm. When the average diameter of the fibers is equal to or more than the preferable lower limit value, the molded product is likely to have rigidity. When it is at most the preferable upper limit value, the moldability will be easily secured.
The fibers that the resin composition may contain may be used alone or in combination of two or more.
When the resin composition contains fibers, the content of fibers in the resin composition is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass based on the total solid content (100% by mass) of the resin composition. It is mass %, and more preferably 40 to 60 mass %.

... Curing agent The resin composition may further include a curing agent depending on the type of the second resin and the like.
For example, when a novolac type phenol resin is used as the second resin, hexamethylenetetramine is usually used as the curing agent.
For example, when an epoxy resin is used as the second resin, the curing agent may be an amine compound such as an aliphatic polyamine, an aromatic polyamine, or dicyaminediamide, an acid anhydride such as an alicyclic acid anhydride, or an aromatic acid anhydride. In addition to compounds, polyphenol compounds such as novolac type phenolic resins, imidazole compounds and the like. Among these, the novolac type phenol resin is preferable from the viewpoint of handleability and environment. In particular, when a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, or a tris(hydroxyphenyl)methane type epoxy resin is used as the epoxy resin, the curing agent is more likely to improve the heat resistance of the cured product. Phenolic resins are preferred.
For example, when a bismaleimide resin is used as the second resin, the curing agent may be an imidazole compound.
The curing agents that the resin composition may contain may be used alone or in combination of two or more.
When the resin composition contains a curing agent, the content of the curing agent in the resin composition is preferably 1 to 20% by mass, more preferably 2% by mass based on the total solid content (100% by mass) of the resin composition. Is about 15% by mass.

... Curing aid Examples of the curing aid include imidazole compounds, tertiary amine compounds, organic phosphorus compounds, magnesium oxide and the like.

... Filler As the filler, an inorganic filler or an organic filler can be used.
Examples of the filler include calcium carbonate, clay, silica, mica, talc, wollastonite, glass beads, milled carbon, graphite, polyvinyl butyral, acrylonitrile butadiene rubber, and wood powder.

... Release Agent Examples of the release agent include zinc stearate, calcium stearate, magnesium stearate and the like.

... Coupling agent Examples of the coupling agent include an epoxysilane coupling agent, a cationic silane coupling agent, an aminosilane coupling agent, and a titanate coupling agent.

... Flame Retardant Examples of the flame retardant include metal hydroxides such as aluminum hydroxide and magnesium hydroxide; antimony compounds, halogen compounds, phosphorus compounds, nitrogen compounds, boron compounds and the like.

  Hereinafter, a method for manufacturing the FRP molded product of this embodiment will be described.

In the manufacturing method of the present embodiment, a molding material (resin composition) is brought into contact with a prepreg (papermaking prepreg) using FRP obtained by a papermaking method, and the papermaking prepreg and the resin composition are molded. Is a method for producing an FRP molded product.
By such a manufacturing method, a papermaking prepreg molded body part or a resin composition molded body part, and an intermediate molded body which is adjacent to at least one of these molded body parts and which contains the component in the papermaking material and the component in the resin composition. And an FRP molded article is manufactured.
As such a manufacturing method, for example, the first to third embodiments described later are preferably cited.

<First Embodiment>
FIG. 1 shows an FRP molded product manufactured by the manufacturing method of the first embodiment.
The FRP molded product 10 shown in FIG. 1 is composed of three parts that are separated by imaginary lines (---), and includes a first molded body part 12, a second molded body part 16, and a first molded body part. 12 and the second molded body portion 16 respectively have a third molded body portion 14 adjacent thereto.
The first molded body portion 12 is composed of a papermaking prepreg molded body portion (cured product containing the first resin and fibers: completely cured product of the papermaking prepreg). That is, in the first molded body portion 12, the fibers are dispersed in the resin matrix derived from the first resin.
The second molded body portion 16 is composed of a resin composition molded body portion (cured product containing the second resin). That is, a resin matrix derived from the second resin is formed on the second molded body portion 16.
The third molded body portion 14 is composed of an intermediate molded body portion in which the papermaking material and the resin composition are mixed.

[First Step (i)]
In this step (i), the molded body produced by removing the dispersion medium from the above-mentioned papermaking material is dried to obtain a papermaking prepreg. That is, a papermaking prepreg is obtained by the papermaking method.
Since the completely cured product (first molded body portion 12) of this paper-making prepreg is provided, the FRP molded product 10 has further improved mechanical properties such as mechanical strength. The reason why such an effect is obtained is not necessarily clear, but it is considered that it is because the fibers (preferably long fibers) are entangled with each other.

In the 1st step (i), for example, an operation of preparing a papermaking material, a papermaking operation, and a drying operation are performed in this order.
-Regarding operation for preparing paper-making material: The above-mentioned first resin, fibers, and optional components (excluding the polymeric flocculant) are added to the dispersion medium and mixed to prepare a dispersion liquid. ..
The method for dispersing the above raw materials in the dispersion medium is not particularly limited, and examples thereof include a method of stirring with a disperser, a homogenizer, or the like.
Then, a polymer coagulant is preferably added to the dispersion. When a powdery substance having an ion-exchange ability is added as an optional component, the effect of this powdery substance facilitates the formation of an aggregated state between the first resin and the fiber, and the raw material in the dispersion is in the form of flocs. In addition, it becomes easier to aggregate.
As described above, the papermaking material in which the raw materials are dispersed in the dispersion medium while being aggregated is prepared.

-Papermaking operation Next, the papermaking material is placed in a chamber (papermaking tank) having a screen (mesh) on the bottom surface, and the dispersion medium is removed through the screen. As a result, the aggregate and the dispersion medium are solid-liquid separated (papermaking operation).
Then, the aggregate is taken out from the chamber to obtain a molded body.

-Drying operation Next, the obtained shaped body is placed in a drying furnace to be dried, thereby further removing the dispersion medium. The drying temperature at this time is preferably 50 to 70°C.
As described above, a papermaking prepreg in which fibers and optional components are dispersed in the resin matrix derived from the first resin is obtained.

[First Step (ii)]
In this step (ii), the papermaking prepreg and the resin composition are molded in a state where the papermaking prepreg obtained in the first step (i) is in contact with the resin composition. Thereby, the FRP molded product 10 is obtained.

For the molding in the first-step (ii), for example, a mold having a pair of heat plates is used. Examples of the molding method include compression molding, transfer molding, and injection molding.
The first step (ii) is performed, for example, as follows.
The papermaking prepreg obtained in the first step (i) is placed on one heating plate in the mold. Then, the resin composition is arranged by injection or the like between the papermaking prepreg and the other heating plate so as to come into contact with one entire surface of the papermaking prepreg.
Next, the papermaking prepreg and the resin composition in the mold are pressed while being heated. At that time, preferably, the papermaking prepreg and the resin composition in the mold are pressurized so as to press the papermaking prepreg with the hot plate. This makes it easier to form the third molded body portion 14.
As the heating conditions, the temperature is appropriately determined depending on the raw materials used and the like, and for example, when a phenol resin is used, the temperature is preferably 150 to 200°C, and more preferably 160 to 180°C.
As the pressurizing condition, the pressure is preferably 10 to 80 MPa, and more preferably 30 to 60 MPa. The pressing time is preferably about 1 to 10 minutes.

According to the manufacturing method of the first embodiment described above, as shown in FIG. 1, the first molded body portion 12, the second molded body portion 16, and the first molded body portion 12 and the second molded body portion 12 are formed. The FRP molded article 10 is manufactured as an integrally molded body having the third molded body portion 14 adjacent to the molded body portion 16 respectively.
In the FRP molded product 10 manufactured by the manufacturing method of the first embodiment, the components contained in both adjacent molded body parts (the first molded body part 12 and the second molded body part 16) are mixed. In addition, since the intermediate molded body portion (third molded body portion 14) is provided, mechanical properties such as bending strength are further enhanced as compared with a completely cured product of the papermaking prepreg and a cured product of the resin composition alone. ..

In the FRP molded product 10, the thickness of each of the first molded body portion 12, the second molded body portion 16 and the third molded body portion 14 is not particularly limited and may be appropriately set depending on the application and the like. Just set it. The thickness of each portion can be controlled by, for example, selecting the heating condition or the pressing condition in the first-step (ii), the composition of the paper-making material, the composition of the resin composition, and the like.
According to the manufacturing method of the first embodiment, for example, the thickness of the first molded body portion 12 is preferably 100 to 4000 μm, and the thickness of the second molded body portion 16 is preferably 1000 to 4000 μm, the third. It is possible to manufacture the FRP molded product 10 in which the thickness of the molded body portion 14 is preferably 50 to 300 μm.

For example, in the FRP molded product 10, the ratio (t ₁₂ /T ₁₀ ) between the total thickness T ₁₀ and the thickness t _{12 of} the first molded body portion 12 is preferably 0.05 or more. It becomes easier to improve the bending strength. When the ratio (t ₁₂ /T ₁₀ ) is 0.10 or more, particularly 0.25 or more, the bending strength is more likely to be increased.

In the FRP molded product 10, the third molded body portion 14 is composed of an intermediate molded body portion in which the papermaking material and the resin composition are mixed.
For example, the third molded body portion 14 is a component (second resin, optional component) contained in the second molded body portion 16 where the fibers are dispersed in the resin matrix derived from the first resin. Are formed by mixing. Alternatively, the third molded body portion 14 is formed by mixing the fibers contained in the first molded body portion 12 with the second resin and optional components contained in the second molded body portion 16. ing.
This has been confirmed by the present inventors by observing with an optical microscope (an epi-illumination image, an image passing through a polarizing filter) and an EDS (Energy Dispersive X-ray Spectroscopy) measurement.
FIG. 2 is a photograph showing a cross section of the FRP molded product 10. The left half of the photograph is an epi-illumination image of the optical microscope, and the right half of the photograph is an image over the polarizing filter of the optical microscope.
The FRP molded article 10 is manufactured by the above <first embodiment> using the following paper-making material and resin composition.

Paper-making material: A composition containing a resol-type phenol resin as a first resin, aramid fibers and aramid pulp as a first fiber, and water as a dispersion medium.
Resin composition: Novolac-type phenol resin as the second resin, glass fiber as the second fiber, hexamethylenetetramine (abbreviated as hexamine), calcium stearate, magnesium oxide, carbon black, and magnesium stearate. A composition containing:

  In FIG. 2, three parts (first molded body part 12, second molded body part 16, third molded body part 14) that are color-coded are observed from an optical microscope (reflection image) observation of the FRP molded product 10, and Two interfaces (interface 13 and interface 15) are recognized.

The first molded body portion 12 is formed of the papermaking material, and the second molded body portion 16 is formed of the resin composition.
From the EDS measurement (mapping image) of the manufactured FRP molded product, a resin composition was obtained in a portion (third molded body portion 14) located between the first molded body portion 12 and the second molded body portion 16. The presence of Mg contained only in the product was recognized.

Further, from an optical microscope (reflection image) observation, in the FRP molded product 10, there is an interface 13 between different resin matrices between the first molded body portion 12 and the third molded body portion 14. Can be confirmed (left side of FIG. 2).
That is, at this interface 13, a resin matrix (resole-type phenol resin) that constitutes the first molded body portion 12 and a resin matrix (condensate of novolac-type phenol resin and hexamine) that is hardened by impregnating the papermaking prepreg. Are in contact with each other.

Further, from the observation with an optical microscope (image through the polarizing filter), in the FRP molded product 10, fibers having different orientations are in contact with each other between the second molded body portion 16 and the third molded body portion 14. It can be confirmed that the interface 15 exists. In addition, it can be confirmed that the fibers contained in the first molded body portion 12 and the third molded body portion 14 have the same orientation state (right side of FIG. 2).
That is, at this interface 15, the fiber 12f (aramid fiber) contained in the first molded body portion 12 and the third molded body portion 14 and the fiber 16f (glass fiber) contained in the second molded body portion 16 are formed. Are in contact with each other.

FIG. 3 is a schematic diagram showing the orientation state of the fibers contained in the first molded body portion 12 and the third molded body portion 14.
In FIG. 3, the fibers 12f (aramid fibers) included in the first molded body portion 12 and the third molded body portion 14 are oriented parallel and randomly in the XY direction (plane direction). In addition, the fibers 12f (aramid fibers) are oriented in the T direction (thickness direction) such that the parallel and randomly oriented fibers 12f (aramid fibers) are stacked. As a result, in particular, the strength with respect to the tensile in the XY direction (plane direction) is increased.
The fibers 12f are thus oriented because the precursors of the first molded body portion 12 and the third molded body portion 14 (papermaking prepreg before curing) are produced by the papermaking method. ..

  On the other hand, the fibers 16f (glass fibers) of the second molded body portion 16 are randomly oriented in both the surface direction and the thickness direction.

 The third molded body portion 14 is composed of a cured product obtained by mixing and curing the resin composition in the papermaking prepreg by observing the optical microscope (an episcopic image, an image passing through a polarizing filter) and EDS measurement. Can be confirmed.

<Second Embodiment>
FIG. 4 shows an FRP molded product manufactured by the manufacturing method of the second embodiment.
The FRP molded product 20 shown in FIG. 4 is composed of two parts separated by an imaginary line (---), and has a second' molded body part 26 and a third' molded body part 24.
The second' molded body portion 26 is composed of a resin composition molded body portion (cured product containing the second resin and fibers). That is, in the second' shaped body portion 26, the fibers are dispersed in the resin matrix derived from the second resin.
The 3'th molded body portion 24 is composed of an intermediate molded body portion in which the papermaking material and the resin composition are mixed.

[Second step (i)]
The second step (i) may be performed in the same manner as the above-mentioned first step (i).

[Second step (ii)]
In the second step (ii), the paper prepreg and the resin composition are molded in a state where the paper prepreg obtained in the second step (i) is in contact with the resin composition. Thereby, the FRP molded product 20 is obtained.
The molding in the second step (ii) may be performed in the same manner as the molding in the first step (ii) except that the following 2a) to 2c) are appropriately adopted. By appropriately adopting the following 2a) to 2c) and performing the molding, the resin composition is sufficiently spread over the entire paper-making prepreg to be cured, and the 3'th molded body portion 24 is easily formed.

2a) Use a large amount of the resin composition for the paper-making prepreg.
2b) The period of time for which the resin composition is injected so as to come into contact with the papermaking prepreg in the mold and then the heating/pressurization is performed is lengthened.
2c) Change heating conditions or pressurizing conditions.

According to the manufacturing method of the second embodiment described above, as shown in FIG. 4, an integrally molded body having a second' molded body portion 26 and a third' molded body portion 24 adjacent thereto. The FRP molded product 20 is manufactured.
In the FRP molded product 20, the 3'th molded body portion 24 is composed of an intermediate molded body portion in which the papermaking material and the resin composition are mixed. That is, the 3′ molded body portion 24 is a component contained in the 2′ molded body portion 26 (a component in the resin composition) in the place where the fibers are dispersed in the resin matrix derived from the first resin. ) Are mixed together.
Further, the FRP molded product 20 has an interface 25 between the second' molded body portion 26 and the 3'th molded body portion 24. In this case, the fibers of the second' shaped body portion 26 and the fibers of the third' shaped body portion 24 have different orientations, and both fibers are in contact at this interface 25. Since the 3′ molded body portion 24 is produced by the papermaking method of the papermaking prepreg before curing, the fibers of the 3′ molded body portion 24 are oriented parallel and randomly in the plane direction, and In the thickness direction, the parallel and randomly oriented fibers are oriented so as to be stacked. On the other hand, the fibers of the second' shaped body portion 26 are randomly oriented in the plane direction and the thickness direction.
The FRP molded product 20 manufactured by the manufacturing method of the second embodiment has higher mechanical properties such as bending strength than the completely cured product of the papermaking prepreg and the cured product of the resin composition alone. There is.

The thickness of each of the second' molded body portion 26 and the 3'th molded body portion 24 is not particularly limited, and may be set appropriately according to the application and the like. The thickness of each portion can be controlled by, for example, selecting the conditions of 2a) to 2c) in the second step (ii), the composition of the paper-making material, the composition of the resin composition, and the like.
According to the manufacturing method of the second embodiment, for example, the thickness of the second' molded body portion 26 is preferably 100 to 4000 μm, and the thickness of the third' molded body portion 24 is preferably 100 to 300 μm. The FRP molded product 20 can be manufactured.
The thickness ratio represented by the thickness of the third' molded body portion 24/the thickness of the second' molded body portion 26 is preferably 0.001 to 3, more preferably 0.001 to 2. , And more preferably 0.001-1. When the thickness ratio is within the above-mentioned preferable range, a laminated structure of the second' molded body portion 26 and the third' molded body portion 24 is easily formed.

<Third Embodiment>
FIG. 5 shows an FRP molded product manufactured by the manufacturing method according to the third embodiment.
The FRP molded product 30 shown in FIG. 5 is composed of two parts separated by an imaginary line (---), and has a first" molded body part 32 and a third" molded body part 34.
The first" molded body portion 32 is composed of a paper-made prepreg molded body portion (cured product containing the first resin and fibers: completely cured product of the paper-made prepreg). That is, the first" molded body portion. In 32, the fibers are dispersed in the resin matrix derived from the first resin.
The third" molded body portion 34 is composed of an intermediate molded body portion in which the papermaking material and the resin composition are mixed.

[Third step (i)]
The third step (i) may be performed in the same manner as the above-mentioned first step (i).

[Third step (ii)]
In the third step (ii), the papermaking prepreg and the resin composition are molded in a state where the above-mentioned resin composition is brought into contact with the papermaking prepreg obtained in the third step (i). Thereby, the FRP molded product 30 is obtained.
The molding in the third step (ii) may be performed in the same manner as the molding in the first step (ii) except that the following 3a) to 3c) are appropriately adopted. By appropriately adopting the following 3a) to 3c) and performing the molding, it becomes easy to form the third" molded body portion 34 in which the entire amount of the resin composition is impregnated in the papermaking prepreg and cured.

3a) Set a small amount of the resin composition used for the papermaking prepreg.
3b) Shorten the standing time from injecting the resin composition so as to come into contact with the papermaking prepreg in the mold and then heating/pressurizing.
3c) Change heating conditions or pressurizing conditions.

According to the manufacturing method of the third embodiment described above, as shown in FIG. 5, an integrally molded body having a first" molded body portion 32 and a third" molded body portion 34 adjacent to the first molded body portion 32. The FRP molded product 30 is manufactured.
In the FRP molded product 30, the third molded body portion 34 is composed of an intermediate molded body portion in which the papermaking material and the resin composition are mixed.
For example, in the third molded body portion 34, the components (second resin, optional component) in the resin composition are mixed in the place where the fibers are dispersed in the resin matrix derived from the first resin. Alternatively, the third "molded body portion 34" comprises the fibers contained in the first "molded body portion 32" and the component (second resin, optional component) in the resin composition. It is formed by mixing.
Further, the FRP molded product 30 has an interface 33 between the first" molded body portion 32 and the third" molded body portion 34. In this case, the resin matrix forming the first" shaped body portion 32 is different from the resin matrix impregnated in the papermaking prepreg and cured, and both resin matrices are in contact with each other at the interface 33.
The FRP molded product 30 manufactured by the manufacturing method of the third embodiment has higher mechanical properties such as bending strength than the completely cured product of the papermaking prepreg alone and the cured product of the resin composition alone. There is.

The thickness of each of the first" molded body portion 32 and the third" molded body portion 34 is not particularly limited, and may be appropriately set according to the application and the like. The thickness of each portion can be controlled by, for example, selecting the conditions of 3a) to 3c) in the third step (ii), the composition of the papermaking material, the composition of the resin composition, and the like.
According to the manufacturing method of the third embodiment, for example, the thickness of the first″ shaped body portion 32 is preferably 100 to 4000 μm, and the thickness of the third″ shaped body portion 34 is preferably 100 to 300 μm. The FRP molded product 30 can be manufactured.
The thickness ratio represented by the thickness of the third" molded body portion 34/the thickness of the first" molded body portion 32 is preferably 0.001 to 3, more preferably 0.001 to 2. , And more preferably 0.001-1. When the thickness ratio is within the above-mentioned preferable range, a laminated structure of the first" molded body portion 32 and the third" molded body portion 34 is easily formed.

<<Other Embodiments>>
In the above-described present embodiment, in the step (ii), the sheet-like FRP molded article is manufactured by injecting the resin composition so as to come into contact with one entire surface of the papermaking prepreg obtained in the step (i). However, the present invention is not limited to this, and the resin composition may be arranged by injection or the like so as to come into contact with a part of the papermaking prepreg. For example, the resin composition is arranged in the papermaking prepreg so as to partially or in contact with the pattern shape, and the resin composition molded body portion having a rib shape or the like is provided on the papermaking prepreg molded body portion via the intermediate molded body portion. You can also
Alternatively, in step (ii), the resin composition is injected so as to come into contact with both surfaces of the paper-prepared prepreg obtained in step (i), and the resin composition is injected onto both surfaces of the paper-prepared prepreg molded body part or on the entire surface or partially. Alternatively, the resin composition molded body portion may be provided in a pattern shape through the intermediate molded body portion.

The FRP molded product manufactured by the method for manufacturing the fiber-reinforced plastic molded product (FRP molded product) of the present embodiment described above can be widely used for various applications such as building materials, automobiles, aircrafts, and sports equipment.
In addition, the method for producing the FRP molded product of the present embodiment is a useful method because it can easily provide required characteristics according to the application and has a high degree of freedom in shape.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited to these examples.

<Manufacture of fiber reinforced plastic moldings>
(Example 1)
Similar to the manufacturing method of the <first embodiment> described above, the first molded body portion 12, the second molded body portion 16, and the first molded body portion 12 and the second molded body portion 16 are formed. An FRP molded article 10 having a third molded body portion 14 respectively adjacent to and was manufactured.

[Step (i)]
-Regarding operation for preparing papermaking material: Resol-type phenol resin (Sumitomo Bakelite Co., Ltd., product number PR-51723) 45% by volume [the same applies to the total solid content (100% by volume) of the papermaking material] and the average fiber 50% by volume of aramid fiber having a diameter of 12 μm and an average length of 3 mm (manufactured by Teijin Limited, product number T32PNW), 5% by volume of aramid pulp (manufactured by DuPont, product number para-aramid alp), and hydrotalcite (Sakai Chemical Co., Ltd.) (Manufactured by Kogyo Co., Ltd., product number STABACE HT-1) 5% by volume was added to water and stirred with a disperser for 20 minutes to obtain a dispersion liquid (solid content concentration: 0.6% by mass).
Next, 0.5 parts by mass of an aggregating agent (polyethylene oxide, molecular weight 1,000,000) previously dissolved in water was added to the obtained dispersion liquid in an amount of 0.5 parts by mass based on 100 parts by mass of the solid content of the dispersion liquid. To prepare a papermaking material.

-Papermaking operation Next, the papermaking material was filtered through a 40-mesh metal net (screen), and the aggregate was dehydrated and pressed at a pressure of 3 MPa to remove water.
Then, the aggregate was taken out to obtain a matrix.

-Drying Operation Next, the obtained molded body was dried at 50°C for 5 hours to obtain a sheet-shaped paper-making prepreg.

[Step (ii)]
-Regarding operation for preparing resin composition Novolak-type phenol resin (Sumitomo Bakelite Co., Ltd., product number A-1084), curing agent hexamethylenetetramine (abbreviated as hexamine), and glass fiber (Nitto Boseki) A resin composition containing cut fiber manufactured by Co., Ltd., average diameter of fiber 11 μm), calcium stearate as a release agent, magnesium oxide as a curing aid, and carbon black as a coloring agent, Prepared in this way.
A mixture of a novolac type phenolic resin and hexamine (47% by mass (novolac type phenolic resin: 40% by mass, hexamine: 7% by mass)), a glass fiber (50% by mass), and a curing agent, which constitute a resin matrix, based on the entire molding material. 1% by mass of the auxiliary agent, 1% by mass of the colorant, and 1% by mass of the releasing agent were blended and premixed to obtain a mixture. The obtained mixture was melt-kneaded at 105° C. with heating rolls having different rotation speeds, cooled into a sheet, and pulverized to prepare a granular resin composition.

-Molding operation As a mold, a mold having a pair of upper and lower heat plates was used.
The papermaking prepreg obtained in step (i) was placed on one heating plate. Next, the resin composition was injected between the papermaking prepreg and the other heating plate so as to contact one entire surface of the papermaking prepreg.
Next, the papermaking prepreg and the resin composition in the mold were pressed while being heated. At that time, the papermaking prepreg and the resin composition in the mold were pressed so as to press the papermaking prepreg with the hot plate.
Molding was performed by setting the temperature as 180° C. as the heating condition, the pressure as 30 MPa as the pressing condition, and the pressing time as 10 minutes.
As a result, an FRP molded product 10 having a length of 80 mm×a width of 50 mm×height (thickness) of 4 mm (thickness of the first molded body portion 12 (only the paper-making prepreg molded body portion) was 1 mm) was obtained.

(Example 2)
An FRP having a length of 80 mm × a width of 50 mm × a height (thickness) of 4 mm was obtained in the same manner as in Example 1 except that the thickness of the first molded body portion 12 (papermaking prepreg molded body portion only) was 0.5 mm. A molded product 10 was obtained.

(Example 3)
An FRP having a length of 80 mm × a width of 50 mm × a height (thickness) of 4 mm was obtained in the same manner as in Example 1 except that the thickness of the first molded body portion 12 (only the paper-making prepreg molded body portion) was 0.25 mm. A molded product 10 was obtained.

(Comparative Example 1)
In the mold used in Example 1, only the resin composition was heated and pressed under the same heating conditions, pressurizing conditions, and pressurizing times as in Example 1 to perform molding.
As a result, a resin composition molded body having a length of 80 mm, a width of 50 mm, and a height (thickness) of 4 mm was obtained.

(Comparative example 2)
The paper-prepared prepreg obtained in the step (i) of Example 1 was pressed while being heated under the same heating conditions, pressurizing conditions, and pressurizing times as in Example 1 to perform molding.
As a result, a papermaking prepreg molded body having a length of 80 mm, a width of 50 mm, and a height (thickness) of 4 mm was obtained.

<Evaluation of FRP molded products>
The molded product manufactured by the manufacturing method of each example was subjected to a three-point bending test as shown in FIG. 6 to measure the bending strength and the bending elastic modulus, respectively. The results are shown in Table 1.
The flexural strength and flexural modulus were measured by the method according to ISO178.

In FIG. 6, the test piece 40 is supported by cylindrical pedestals 50a and 50b arranged so as to contact both ends 40a and 40b in the longitudinal (longitudinal) direction of the lower surface 40d.
A bending test is performed by applying a load (thick arrow) to the center of the upper surface 40c of the test piece 40 in this state.
FIG. 6 shows a case where the FRP molded product 10 manufactured by the manufacturing method of the embodiment is used as the test piece 40. In this case, the papermaking prepreg molded body portion 42 is arranged on the lower surface 40d side of the test piece 40, the resin composition molded body portion 46 is arranged on the upper surface 40c side, and the intermediate molded body portion 44 is arranged therebetween.

  From the results shown in Table 1, it was confirmed that according to the manufacturing method of the present embodiment, it is possible to manufacture an FRP molded product having higher bending strength as compared with the papermaking prepreg molded product alone and the resin composition molded product alone. it can.

10 FRP molded article, 12 1st molded article part, 13 interface, 14 3rd molded article part, 15 interface, 16 2nd molded article part, 20 FRP molded article, 24 3'molded article part, 25 Interface, 26 2'molded part, 30 FRP molded part, 32 1" molded part, 33 Interface, 34 3" molded part, 40 Test piece, 42 Paper-prepreg molded part, 44 Intermediate Molded body part, 46 Resin composition molded body part

Claims (3)

A step (i) of obtaining a papermaking prepreg by drying a shaped body produced by removing a dispersion medium from a papermaking material containing a first resin, a first fiber and a dispersion medium, and
At least one surface of the papermaking prepreg is heated in a state in which a resin composition containing a second resin and a second fiber is contacted to mold the papermaking prepreg and the resin composition, a papermaking prepreg formed body portion, a resin composition molded article portions respectively adjacent to the molded body portion of these both, are formed by components and components of the resin composition in the papermaking material are mixed together (Ii) obtaining a fiber-reinforced plastic molded product having an intermediate molded body part having
A method for producing a fiber-reinforced plastic molded article , comprising:
The fiber-reinforced plastic molded product obtained in the step (ii) is
Between the papermaking prepreg molded body portion and the intermediate molded body portion, there is an interface in which different resin matrices are in contact with each other,
Between the intermediate molded body portion and the resin composition molded body portion, there is an interface in which fibers having different orientations are in contact with each other,
The first fibers are oriented in parallel and randomly in the surface direction of the papermaking prepreg molded body part and the intermediate molded body part, and in the thickness direction of the papermaking prepreg molded body part and the intermediate molded body part, Are oriented so that parallel and randomly oriented fibers of
The method for producing a fiber-reinforced plastic molded product, wherein the second fibers are randomly oriented in the plane direction and the thickness direction of the resin composition molded body portion . A step (i) of obtaining a papermaking prepreg by drying a shaped body produced by removing a dispersion medium from a papermaking material containing a first resin, a first fiber and a dispersion medium, and
The papermaking prepreg and the resin composition are molded by heating the papermaking prepreg in a state where the resin composition containing the second resin and the second fiber is in contact with the whole of the papermaking prepreg to form a resin composition. Fiber reinforced comprising a molded body portion and an intermediate molded body portion which is adjacent to the resin composition molded body portion and which is formed by mixing components in the papermaking material and components in the resin composition. Process for obtaining a plastic molded product (iii)
A method for producing a fiber-reinforced plastic molded article, comprising:
The fiber-reinforced plastic molded product obtained in the step (iii) is
Between the resin composition molded body portion and the intermediate molded body portion, there is an interface in which fibers having different orientations are in contact with each other,
The first fibers are oriented in parallel and randomly in the surface direction of the intermediate molded body portion, and are oriented in the thickness direction of the intermediate molded body portion such that the parallel and randomly oriented fibers are stacked. And
The method for producing a fiber-reinforced plastic molded product, wherein the second fibers are randomly oriented in the plane direction and the thickness direction of the resin composition molded body portion . A step (i) of obtaining a paper-prepared prepreg by drying a molded body produced by removing the dispersion medium from the paper-making material containing the first resin, the fiber and the dispersion medium, and
A part of the papermaking prepreg is impregnated with the total amount of the resin composition containing the second resin to heat the papermaking prepreg and the resin composition to form a papermaking prepreg molded body portion. A fiber reinforced plastic molded article having an intermediate molded body portion adjacent to the papermaking prepreg molded body portion and formed by mixing components in the papermaking material and components in the resin composition Process (iv)
A method for producing a fiber-reinforced plastic molded article, comprising:
The fiber-reinforced plastic molded product obtained in the step (iv) does not have an interface where fibers having different orientations are in contact with each other, and a different resin is provided between the papermaking prepreg molded body part and the intermediate molded body part. A method for producing a fiber-reinforced plastic molded article, wherein an interface where the matrices are in contact with each other is present .