JP7419291B2 - Method for manufacturing fiber-reinforced molded body, resin sheet, and method for manufacturing resin sheet - Google Patents

Description

The present disclosure relates to a fiber-reinforced molded article, a method for manufacturing a fiber-reinforced molded article, and a resin sheet.

In recent years, composite materials (FRP) made of reinforcing fiber base materials such as carbon fibers and glass fibers and resins have been widely used in various fields and applications for the purpose of reducing weight and improving mechanical strength. In particular, in transportation equipment such as automobiles, trains, and airplanes, there is a high demand for lower fuel consumption and the weight reduction of the aircraft body is highly effective, so FRP is expected to be used as a metal substitute material for these applications.
As a method for molding FRP, there is a method in which a reinforcing fiber base material is impregnated with a resin to form a prepreg, and then the prepreg is molded using an autoclave, a hot press, or the like. The resin that is impregnated into the reinforcing fibers is generally in liquid form, but there are problems with the pot life of the resin, and when a solvent is used, there are problems with the working environment and air pollution. As a method for solving these problems, a prepreg impregnated with powder resin has been proposed (see Patent Document 1).

Japanese Patent Application Publication No. 2006-232915

In the above-mentioned patent documents, after producing a resin-impregnated body (prepreg), a final molded body is molded.
Molding using prepreg has the problem of high manufacturing costs because the prepreg process requires large-scale equipment and the prepreg process is complicated to manage.
The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a fiber-reinforced molded article that can be manufactured at low cost.
The present disclosure can be realized as the following forms.

A fiber-reinforced molded article in which a fiber base material is integrated with the thermosetting resin of a resin sheet containing a thermosetting resin,
The thermosetting resin is a fiber having a viscosity of 2,000 Pa·s or less at a curing reaction starting temperature Tb°C and a maximum viscosity of 1,000 Pa·s or more in a range of curing reaction starting temperature Tb°C to 190°C. Reinforced molded body.

The fiber-reinforced molded article of the present disclosure can be manufactured at low cost.

FIG. 1 is a cross-sectional view of a fiber-reinforced molded article according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing lamination and heat compression in an embodiment of the method for manufacturing a fiber-reinforced molded article of the present disclosure. FIG. 3 is a cross-sectional view showing lamination and heat compression in an embodiment of the method for manufacturing a fiber-reinforced molded article of the present disclosure. FIG. 4 is a cross-sectional view showing lamination and heat compression in an embodiment of the method for manufacturing a fiber-reinforced molded article of the present disclosure. 1 is a graph showing the viscosity measurement results of mixed resins used in Examples 1 and 6-10 and Comparative Examples 1 and 2.

Here, a desirable example of the present disclosure will be shown.
- The resin sheet is a fiber-reinforced molded body including a sheet base material.
- The thermosetting resin has a melting start temperature of Ta°C and a curing reaction start temperature of Tb°C.
The value of (Tb-Ta) is
30≦(Tb-Ta)≦100
A fiber-reinforced molded body that satisfies the following requirements.
- The thermosetting resin is a phenol resin, a mixed resin of a phenol resin and an epoxy resin, a mixed resin of a phenol resin and a cyanate resin, a mixed resin of an epoxy resin and a cyanate resin, and a mixed resin of a phenol resin, an epoxy resin, and a cyanate resin. A fiber-reinforced molded body made of a resin selected from the group consisting of resins.
- A method for producing a fiber-reinforced molded article, comprising:
A method for manufacturing a fiber-reinforced molded article, comprising heating and compressing the fiber base material and the resin sheet in a stacked state using a mold, impregnating the thermosetting resin into the fiber base material, and curing the resin sheet.
・Temperature Tc℃ during heating compression is
[Tb+(Tb-Ta)/3]-15≦Tc≦[Tb+(Tb-Ta)/3]+20, a method for producing a fiber-reinforced molded body.
A resin sheet for producing a fiber-reinforced molded article,
A resin sheet containing thermosetting resin.
- A fiber-reinforced molded body in which a fiber base material is integrated with the thermosetting resin of a resin sheet containing a thermosetting resin,
The resin sheet is a fiber-reinforced molded body including a sheet base material.

The present disclosure will be described in detail below. In this specification, descriptions using "~" for numerical ranges include the lower limit and upper limit unless otherwise specified. For example, the description "10 to 20" includes both the lower limit value of "10" and the upper limit value of "20". That is, "10 to 20" has the same meaning as "10 or more and 20 or less".

1. Fiber reinforced molded body 10
In the fiber-reinforced molded body 10, a fiber base material 11 is integrated with a thermosetting resin of a resin sheet 15 containing a thermosetting resin. The thermosetting resin has a viscosity of 2,000 Pa·s or less at the curing reaction starting temperature Tb°C and a maximum viscosity of 1,000 Pa·s or more in the range of the curing reaction starting temperature Tb°C to 190°C.

(1) Fiber base material 11
The fiber base material 11 may have a single layer or multiple layers, and the number of layers is determined depending on the use of the fiber-reinforced molded product 10 and the like. In the embodiments of FIGS. 1 and 2, the fiber base material 11 is illustrated as having four layers. Examples of the fiber base material 11 include woven fabrics and nonwoven fabrics made of glass fibers, aramid fibers, basalt fibers, carbon fibers, etc., and are not particularly limited, but carbon fiber woven fabrics are preferred because they are lightweight and have high rigidity. It is. The carbon fiber fabric preferably has a weave in which the fibers are not woven in one direction only, such as plain weave, twill weave, satin weave, which is composed of warp and weft threads, and triaxial weave, which is composed of threads in three directions. It is. Further, the carbon fiber fabric preferably has a fiber weight of 50 to 600 g/m ² from the viewpoint of impregnation with the thermosetting resin contained in the resin sheet 15 and the rigidity of the fiber-reinforced molded body 10.

(2) Resin sheet 15 containing thermosetting resin
The thermosetting resin used is one that is solid at room temperature (5° C. to 35° C.) when producing the fiber-reinforced molded body 10. The shape of the solid is not particularly limited. Examples of solid shapes include powders such as spherical, acicular, and flake shapes.

It is preferable that the resin sheet 15 includes a sheet base material. Since the resin sheet 15 includes a sheet base material, the strength of the resin sheet 15 is increased, and the handling properties of the resin sheet 15 are improved. Note that even if the resin sheet 15 does not include a sheet base material, the handling properties are better than in the case where powdered resin is used.
The structure of the sheet base material is not particularly limited. It is preferable that the sheet base material has a structure that allows the molten resin to penetrate. The structure through which the molten resin can penetrate is not particularly limited, but examples include structures having communicating holes. Further, it is preferable that the sheet base material does not melt at the reaction start temperature (Tb) of the thermosetting resin.
The sheet base material is preferably one or more selected from the group consisting of foam, nonwoven fabric, and fiber sheet. When the sheet base material has these structures, the thermosetting resin can be sufficiently held in the space within the sheet base material.
The material of the sheet base material is not particularly limited. The material of the sheet base material is preferably one or more selected from the group consisting of urethane, rayon, polyester, and carbon.
Specifically, the sheet base material is preferably one or more selected from the group consisting of a urethane foam, a nonwoven fabric of rayon and polyester (PET), a PET nonwoven fabric, and a carbon fiber sheet.
The thickness of the resin sheet base material is not particularly limited. The thickness of the resin sheet base material is preferably 0.05 mm or more and 1.0 mm or less, and more preferably 0.08 mm or more and 0.7 mm or less, from the viewpoint of sufficiently retaining the thermosetting resin necessary for adhesion.
The basis weight of the resin sheet base material is not particularly limited. The basis weight of the resin sheet base material is preferably 20 g/m ² or more and 50 g/m ² or less, more preferably 30 g/m ² or more and 45 g/m ² or less.

The resin sheet 15 is arranged so as to be in contact with the fiber base material 11. When the fiber base material 11 is heated and compressed together with the resin sheet 15, the thermosetting resin contained in the resin sheet 15 is melted, impregnated into the fiber base material 11, and hardened. In the case where the fiber base material 11 is a single layer, the resin sheet 15 is placed in contact with the fiber base material 11 on at least one of the upper surface and the lower surface of the single layer fiber base material 11. will be placed in In addition, when the fiber base material 11 has multiple layers, the resin sheet 15 is arranged on at least one surface, that is, at least one of the uppermost surface, the lowermost surface, and the laminated surface (between the fiber base materials) of the multiple layers. Examples include aspects in which this is done.

The thermosetting resin preferably satisfies 30≦(Tb−Ta)≦100, where melting start temperature Ta° C. and curing reaction start temperature Tb° C. are assumed. By setting (Tb-Ta) within this range, the fiber base material 11 can be sufficiently impregnated with the molten thermosetting resin, and a fiber-reinforced molded article 10 having uniform physical properties can be obtained.

The thermosetting resin has a minimum viscosity of 2,000 Pa·s or less at a temperature higher than the melting start temperature Ta°C. This minimum viscosity is preferably 1,500 Pa·s or less. By setting the minimum viscosity within this range, the fiber base material 11 can be sufficiently impregnated with the molten thermosetting resin, and a fiber-reinforced molded article 10 having uniform physical properties can be obtained. The lower limit of the minimum viscosity is not particularly limited. The lower limit of the minimum viscosity is preferably 0.005 Pa·s.
Note that the lowest viscosity at a temperature equal to or higher than the melting start temperature Ta°C is the same as the viscosity at the curing reaction start temperature Tb°C.

Further, the thermosetting resin preferably has a maximum viscosity of 1,000 Pa·s or more in the temperature range from the curing reaction start temperature Tb°C to 190°C. By setting the maximum viscosity within this range, the molten thermosetting resin can be impregnated and retained in the fiber base material 11, and the shapeability of the fiber-reinforced molded product 10 is good, and sufficient strength can be achieved in a short time. can get. The upper limit of the highest viscosity is not particularly limited, but the upper limit is preferably 300,000 Pa·s.
The thermosetting resin preferably has a melting start temperature Ta°C of 60 to 100°C. By setting the melting start temperature Ta° C. of the thermosetting resin within this range, the laminate in which the resin sheet 15 is disposed in at least one space between the fiber base materials 11 is heated and compressed to melt and harden the thermosetting resin. Temperature can be easily controlled during heating.

Thermosetting resins that can satisfy the melting start temperature Ta°C, curing reaction start temperature Tb°C, (Tb-Ta) range, minimum viscosity, and maximum viscosity are phenolic resins and mixed resins of phenolic resins and epoxy resins. , a mixed resin of a phenol resin and a cyanate resin, a mixed resin of an epoxy resin and a cyanate resin, and a mixed resin of a phenol resin, an epoxy resin, and a cyanate resin. Since phenol resin has excellent flame retardancy, it can impart excellent strength and flame retardance to the fiber-reinforced molded article 10.
As the phenol resin, for example, a novolak type powdered phenol resin is preferably used. The physical properties of the phenol resin are not particularly limited. For example, a phenol resin having the following physical properties is suitably employed.
・Melting point: 80℃ or higher and 100℃ or lower

As the epoxy resin, for example, bisphenol A solid resin is preferably used. The physical properties of the epoxy resin are not particularly limited. For example, epoxy resins having the following physical properties are preferably employed.
・Epoxy equivalent: 400g/eq or more and 1000g/eq or less ・Softening point: 60℃ or more and 100℃ or less ・Viscosity: 0.10Pa・s or more and 0.30Pa・s or less (25℃)

Cyanate resin is a thermosetting resin having a cyanate group, and is also called cyanate monomer. The physical properties of the cyanate resin before curing are not particularly limited. For example, cyanate resins having the following physical properties are preferably employed.
・Melting point: 75℃ or more and 85℃ or less ・Viscosity: 0.010Pa・s or more and 0.015Pa・s or less (80℃)

Note that various powder additives such as pigments, antibacterial agents, and ultraviolet absorbers may be added to the thermosetting resin within a range that does not affect the viscosity and reactivity of the thermosetting resin.

The basis weight of the thermosetting resin in the resin sheet 15 is not particularly limited. The basis weight of the thermosetting resin is preferably 200 g/m ² or more and 800 g/m 2 or less, and 400 g/m 2 or more and 600 g/m 2 or less, from the viewpoint of ensuring the strength of ^{the fiber-} reinforced molded product ¹⁰ and not impairing the appearance. m ² or less is more preferable.

(3) Physical properties of fiber-reinforced molded product 10 The flexural modulus (JIS K7074 A method) of fiber-reinforced molded product 10 is not particularly limited. From the viewpoint of high rigidity, the bending elastic modulus of the fiber-reinforced molded body 10 is preferably 40 GPa or more, and more preferably 50 GPa or more.
The bending strength (JIS K7074 A method) of the fiber-reinforced molded product 10 is not particularly limited. From the viewpoint of high strength, the bending strength of the fiber-reinforced molded body 10 is preferably 400 MPa or more, more preferably 800 MPa or more.
The specific gravity of the fiber-reinforced molded body 10 is not particularly limited. The specific gravity of the fiber-reinforced molded body 10 is preferably 1.10 or more and 1.80 or less, more preferably 1.30 or more and 1.69 or less, from the viewpoint of reducing weight and not impairing the appearance.

2. Method for manufacturing fiber-reinforced molded product 10 The method for manufacturing fiber-reinforced molded product 10 of the present disclosure involves heating and compressing the fiber base material 11 and resin sheet 15 in a stacked state using a mold to inject the thermosetting resin into the fiber base material. This is done by impregnating the material 11 and curing it. Regarding the fiber base material 11, the resin sheet 15, and the thermosetting resin, the description in "1. Fiber-reinforced molded product 10" is quoted as is.

As described above, the resin sheet 15 is arranged on at least one of the upper surface and the lower surface of the fiber base material 11 in the case of a single layer, and in the case of the fiber base material 11 in multiple layers. It is arranged on at least one surface of the uppermost surface, the lowermost surface, and the laminated surface (between the fiber base materials 11) in the plurality of layers.
Note that when the resin sheet 15 is arranged on a laminated surface (between fiber base materials 11) of multiple layers of fiber base materials 11, it is not limited to one lamination surface (between one fiber base material 11), but on all laminated surfaces. It may be arranged on a surface (between all fiber base materials) or on every predetermined number of laminated surfaces (between every predetermined number of fiber base materials 11), and the position of the surface to be placed and the number of surfaces to be placed will depend on the fiber base material. It is determined as appropriate depending on the number of laminated layers of 11, etc.
In addition, when placing the resin sheet 15 in contact with the top or bottom surface of a single-layer fiber base material 11 or the top or bottom surface of a multi-layer fiber base material 11, for convenience of work, the resin sheet 15 may be A release sheet may be placed between the mold surface and the mold surface.

An embodiment of a method for manufacturing the fiber-reinforced molded body 10 in which the fiber base material 11 shown in FIG. 1 is composed of four layers will be described with reference to FIG. 2. In addition, in the following description of the manufacturing method, in order to make it easier to understand the vertical positional relationship of a plurality of fiber base materials 11, a plurality of fiber base materials 11 will be designated by a code that is a combination of "11" and "alphabet", such as "11A". A fiber base material 11 is shown. Similarly, in order to make it easier to understand the vertical positional relationship of the plurality of resin sheets 15, the plurality of resin sheets 15 are indicated by a code that is a combination of "15" and "alphabet", such as "15A".

In the embodiment shown in FIG. 2, when four fiber base materials 11A to 11D are laminated, the lower two fiber base materials 11A and 11B and the upper two fiber base materials 11C and 11D are stacked together. Resin sheets 15A and 15B are arranged between the fiber base materials 11 (between the fiber base materials 11B and 11C).
The amount of thermosetting resin contained in the resin sheets 15A and 15B is preferably adjusted so that the VF value (%) of the fiber-reinforced molded body 10 is 40 to 70%. The VF value (%) is a value calculated by (total weight of fiber base material/density of fiber)/(volume of fiber reinforced molded body)×100.

A laminate of fiber base materials 11A to 11D, in which the resin sheets 15A and 15B are arranged and laminated between the fiber base materials 11B and 11C, is placed in the lower mold 31 of the heated mold 30. It is sandwiched between the upper molds 32 and heated and compressed. The mold 30 is heated by heating means such as an electric heater to a temperature Tc° C. at which the thermosetting resin can be melted and hardened.
The temperature Tc°C during heating and compression (temperature Tc°C of the mold 30) is in relation to the melting start temperature Ta°C of the thermosetting resin and the curing reaction start temperature Tb°C.
[Tb+(Tb-Ta)/3]-15≦Tc≦[Tb+(Tb-Ta)/3]+20
It is preferable that For example, if Ta°C=70°C and Tb°C=130°C, Tc°C will be 135°C to 170°C.

The pressurization (compression) of the fiber base materials 11A to 11D during heat compression by the mold 30 is performed after the thermosetting resin contained in the resin sheets 15A and 15B between the fiber base materials 11 is melted. In order to be able to satisfactorily impregnate 11D, the pressure is preferably 2 MPa to 20 MPa.
In addition, the compression rate (%) of the fiber base materials 11A to 11D is calculated as follows: (distance between the mold surface of the lower mold 31 and the mold surface of the upper mold 32)/(total thickness of all layers of the fiber base material)×100. This is a calculated value, and is preferably 60 to 100%.

By heating the laminate with the mold 30, the thermosetting resin contained in the resin sheets 15A and 15B between the fiber base materials 11 (between the fiber base materials 11B and 11C) is melted, and the melted heat is The curable resin impregnates the lower fiber base materials 11B, 11A and the upper fiber base materials 11C, 11D by compressing the laminate. Then, by curing the thermosetting resin impregnated into the fiber base materials 11A to 11D, the fiber base materials 11A to 11D are integrated in a compressed state and shaped into the mold surface shape of the lower mold 31 and the upper mold 32. The fiber-reinforced molded article 10 shown in FIG. 1 is obtained.

FIG. 3 shows an embodiment in which four fiber base materials 11A to 11D are stacked, resin sheets 15A to 15C are placed between all the fiber base materials, and heated and compressed using a mold 30.
The amount (total amount) of the thermosetting resin, the heating temperature of the mold 30, the pressurization of the laminate, etc. are as described in the embodiment of FIG. 2.

In the embodiment shown in FIG. 4, when stacking ten fiber base materials 11A to 11J, the lower five fiber base materials 11A to 11E and the upper five fiber base materials 11F to 11J are stacked. Five resin sheets 15A to 15E are arranged between the fiber base materials 11 (between the fiber base materials 11E and 11F).

3. Resin sheet 15
The resin sheet 15 for manufacturing the fiber-reinforced molded body 10 contains a thermosetting resin. That is, the resin sheet 15 supports the thermosetting resin in an uncured state. Regarding the resin sheet 15 and the thermosetting resin, the description in "1. Fiber-reinforced molded product 10" is quoted as is.

Using the thermosetting resins shown in Tables 1 and 2, fiber-reinforced molded bodies of Examples 1 to 10 and Comparative Examples 1 and 2 were produced as follows. Table 4 summarizes the characteristics of various sheet base materials used for producing the fiber-reinforced molded product. The viscosity of the thermosetting resin was measured using a rheometer: Rheosol-G3000 manufactured by UBM Co., Ltd. under the following conditions.
1) Form 0.4 g of the sample into pellets (diameter φ18 mm, thickness approximately 0.4 mm), and sandwich the formed pellets between parallel plates having a diameter φ18 mm.
2) Dynamic viscosity was measured at 2°C intervals over a temperature range of 40°C to 200°C under constant temperature increase at a temperature increase rate of 5°C/min, frequency of 1Hz, rotation angle (strain) of 0.1deg.

1. Production of fiber-reinforced molded body (1) Example 1
As solid thermosetting resins, cyanate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: CYTESTER TA, average particle size: 100 μm) and epoxy resin (manufactured by DIC Corporation, product name: AM-020-P, average particle size: 100 μm) were used. ) and phenol resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50235D, average particle size: 90 μm) at a weight ratio of 3:1:1 was used.
The properties of the mixed resin of Example 1 are as follows and are listed in Tables 1 and 2. The viscosity measurement results of the mixed resin of Example 1 are shown in the graph of FIG.

・Melting start temperature Ta: 69°C
・Reaction starting temperature Tb: 135°C
・(Tb-Ta): 66℃
・Minimum viscosity (minimum viscosity at a temperature equal to or higher than melting start temperature Ta°C): 59 Pa・s
- Maximum viscosity (highest viscosity in the temperature range from curing reaction start temperature Tb°C to 190°C)
:8,768Pa・s
・Value of (Tb-Ta)/3: 22℃
・Value of Tb+(Tb-Ta)/3: 157°C

As the sheet base material of the resin sheet, the PET nonwoven fabric shown in Table 4 (manufactured by Nippon Vilene Co., Ltd., product name: JH-1004N1, basis weight: 45 g/m ² , thickness 0.08 mm) cut into 200 mm x 250 mm was used. there was.
20 g of the above solid thermosetting resin was placed on one sheet base material to produce a pre-molding sheet base material.
Next, one sheet base material before molding is placed on the molding surface of the lower die of the mold heated to 100°C, and then the mold is closed and heat-compressed at a pressure of 1 MPa for 1 minute to form the sheet base material. A solid thermosetting resin was melted and supported. Thereafter, a resin sheet was produced by cooling.
Two resin sheets produced in this manner were prepared. The thickness of the resin sheet was adjusted by interposing a 1 mm thick SUS spacer between the lower mold and the upper mold, and a 0.05 mm thick PET film above and below the sheet base material before molding.
As a reinforcing fiber base material, four pieces of carbon fiber fabric (manufactured by Teijin Ltd., product name: W-3101, basis weight: 200 g/m ² , thickness 0.22 mm) cut into 200 mm x 250 mm were prepared. The weight of each carbon fiber fabric after cutting was 12 g. First, two carbon fiber fabrics were placed, and then two resin sheets and then two carbon fiber fabrics were placed in this order to produce a pre-molding laminate. FIG. 2 schematically shows the stacked state. In Example 1, as shown in FIG. 2, two resin sheets are arranged between a central fiber base material (carbon fiber fabric) to form a pre-molding laminate.
Next, the pre-molding laminate was placed on the molding surface of the lower mold of the mold heated to 160°C, and then the mold was closed and compressed under heat for 10 minutes at a pressure of 10 MPa to form a solid thermosetting resin. Melt hardened. When the solid thermosetting resin is melted and pressure is applied, the resin impregnates the fiber base material of each layer, and then the thermosetting resin of the solid thermosetting resin is completed, and the thermosetting resin of the resin sheet A fiber-reinforced molded body with an integrated fiber base material was produced. Note that a 1 mm thick SUS spacer was interposed between the lower mold and the upper mold for press molding to adjust the distance between the lower mold and the upper mold, thereby adjusting the thickness of the fiber-reinforced molded body.

(2) Example 2
As solid thermosetting resins, cyanate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: CYTESTER TA, average particle size: 100 μm) and epoxy resin (manufactured by DIC Corporation, product name: AM-030-P, average particle size: 100 μm) ) and phenol resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50235D, average particle size: 90 μm) at a weight ratio of 1:1:1. A fiber-reinforced molded body was produced in the same manner as in Example 1, except that the mold temperature was 150°C.
The properties of the mixed resin of Example 2 are as follows and are listed in Tables 1 and 2.

・Melting start temperature Ta: 95°C
・Reaction starting temperature Tb: 135°C
・(Tb-Ta): 40℃
・Minimum viscosity (minimum viscosity at a temperature higher than the melting start temperature Ta°C): 1,500 Pa・s
- Maximum viscosity (highest viscosity in the temperature range from curing reaction start temperature Tb°C to 190°C)
:209,004Pa・s
・Value of (Tb-Ta)/3: 13°C
・Value of Tb+(Tb-Ta)/3: 148℃

(3) Example 3
As solid thermosetting resins, phenol resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50252, average particle size: 30 μm) and epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name: jER-1001, average particle size: 100 μm) A fiber-reinforced molded body was produced in the same manner as in Example 1, except that a mixed resin uniformly mixed at a weight ratio of 1:1 was used, and the mold temperature during molding of the fiber-reinforced molded body was 150°C. .
The properties of the mixed resin of Example 3 are as follows and are listed in Tables 1 and 2.

・Melting start temperature Ta: 73°C
・Reaction starting temperature Tb: 140°C
・(Tb-Ta): 67℃
・Minimum viscosity (minimum viscosity at a temperature higher than the melting start temperature Ta°C): 22 Pa・s
- Maximum viscosity (highest viscosity in the temperature range from curing reaction start temperature Tb°C to 190°C)
:5,180Pa・s
・Value of (Tb-Ta)/3: 22℃
・Value of Tb+(Tb-Ta)/3: 163℃

(4) Example 4
As solid thermosetting resins, phenol resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50235D, average particle size: 90 μm) and cyanate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: CYTESTER TA, average particle size: 100 μm) A fiber-reinforced molded body was produced in the same manner as in Example 1, except that a mixed resin uniformly mixed at a weight ratio of 1:1 was used, and the mold temperature during molding of the fiber-reinforced molded body was 170°C. .
The properties of the mixed resin of Example 4 are as follows and are listed in Tables 1 and 2.

・Melting start temperature Ta: 76°C
・Reaction start temperature Tb: 138°C
・(Tb-Ta): 62℃
・Minimum viscosity (minimum viscosity at a temperature equal to or higher than the melting start temperature Ta°C): 475 Pa・s
- Maximum viscosity (highest viscosity in the temperature range from curing reaction start temperature Tb°C to 190°C)
:51,895Pa・s
・(Tb-Ta)/3 value: 21℃
・Value of Tb+(Tb-Ta)/3: 159°C

(5) Example 5
As solid thermosetting resins, epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name: jER-1001, average particle size: 100 μm) and cyanate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: CYTESTER TA, average particle size: 100 μm) A fiber-reinforced molded body was produced in the same manner as in Example 1, except that a mixed resin uniformly mixed at a weight ratio of 1:1 was used, and the mold temperature during molding of the fiber-reinforced molded body was 170°C. did.
The properties of the mixed resin of Example 5 are as follows and are listed in Tables 1 and 2.

・Melting start temperature Ta: 75°C
・Reaction start temperature Tb: 139°C
・(Tb-Ta): 64℃
・Minimum viscosity (minimum viscosity at a temperature equal to or higher than the melting start temperature Ta°C): 575 Pa・s
- Maximum viscosity (highest viscosity in the temperature range from curing reaction start temperature Tb°C to 190°C)
:19,025Pa・s
・(Tb-Ta)/3 value: 21℃
・Value of Tb+(Tb-Ta)/3: 160℃

(6) Example 6
Four reinforcing fiber base materials similar to those in Example 1 and three resin sheets similar to those in Example 1 were prepared, and as shown in FIG. 3, one resin sheet was placed between each fiber base material layer. A fiber-reinforced molded body was produced in the same manner as in Example 1 except for the arrangement.

(7) Example 7
Ten reinforcing fiber base materials similar to those in Example 1 were prepared, five of the fiber base materials were laminated, five resin sheets were placed on top of that, and the remaining five fiber sheets were placed on top of that. A fiber-reinforced molded article was produced in the same manner as in Example 1, except that the pre-molding base material was produced by laminating the base materials. FIG. 4 schematically shows the stacked state.

(8) Example 8
Example 1 except that a urethane resin foam (manufactured by INOAC Corporation, product name: MF-50, basis weight 35 g/m ² ) cut out into a sheet with a thickness of 0.7 mm and a planar size of 200 mm x 300 mm was used as the sheet base material. A fiber-reinforced molded body was produced in the same manner.

(9) Example 9
Example 1 except that a rayon/polyester nonwoven fabric (manufactured by Kuraray Trading Co., Ltd., product name: SF-30C, basis weight 31 g/m ² ) cut out to a thickness of 0.22 mm and a planar size of 200 mm x 300 mm was used as the sheet base material. A fiber-reinforced molded body was produced in the same manner.

(10) Example 10
Example 1 except that a carbon fiber sheet (manufactured by Awa Paper Co., Ltd., product name: CARMIX C-2, basis weight 31 g/m ² ) cut out to a thickness of 0.34 mm and a planar size of 200 mm x 300 mm was prepared as a sheet base material. A fiber-reinforced molded body was produced in the same manner.

(11) Comparative example 1
A phenol resin (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50699, average particle size: 30 μm) was used as the solid thermosetting resin, and the mold temperature was 80°C during resin sheet production to form a fiber-reinforced molded product. A fiber-reinforced molded body was produced in the same manner as in Example 1, except that the mold temperature at the time was 100°C. The viscosity of the resin was high (the reaction was fast) and the impregnating properties of the resin were poor, making it impossible to obtain a uniform fiber-reinforced molded article.
The properties of the resin of Comparative Example 1 are as follows and are listed in Tables 1 and 2. The viscosity measurement results of the resin of Comparative Example 1 are shown in the graph of FIG.

・Melting start temperature Ta: 72°C
・Reaction start temperature Tb: 91°C
・(Tb-Ta): 19℃
・Minimum viscosity (minimum viscosity at a temperature higher than the melting start temperature Ta°C): 118,908 Pa・s
- Maximum viscosity (highest viscosity in the temperature range from curing reaction start temperature Tb°C to 190°C)
:164,468Pa・s
・Value of (Tb-Ta)/3: 6℃
・Value of Tb+(Tb-Ta)/3: 100℃

(12) Comparative example 2
As the solid thermosetting resin, two types of phenolic resins (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-50252, average particle size: 30 μm and Sumitomo Bakelite Co., Ltd., product name: PR-50235D, average particle size: 90 μm) were used. A fiber-reinforced molded body was produced in the same manner as in Example 1, except that a 1:2 mixed resin (weight ratio) was used and the mold temperature during molding of the fiber-reinforced molded body was 160°C. The resin was not sufficiently cured, resulting in deformation during demolding.
The properties of the resin of Comparative Example 2 are as follows and are listed in Tables 1 and 2. The viscosity measurement results of the resin of Comparative Example 2 are shown in the graph of FIG.

・Melting start temperature Ta: 80°C
・Reaction starting temperature Tb: 140°C
・(Tb-Ta): 60℃
・Minimum viscosity (minimum viscosity at a temperature higher than the melting start temperature Ta°C): 21 Pa・s
・Maximum viscosity (highest viscosity in the temperature range of curing reaction start temperature Tb°C to 190°C): 260 Pa・s
・Value of (Tb-Ta)/3: 20℃
・Value of Tb+(Tb-Ta)/3: 160℃

2. Physical properties, etc. of fiber-reinforced molded products (1) Measurement method Regarding the fiber-reinforced molded products of Examples 1 to 10 and Comparative Examples 1 and 2, the thickness (mm), bending strength (MPa), bending modulus (GPa) were measured and Judging the appearance. The results are shown in Table 3.
Bending strength and bending elastic modulus were measured by cutting out a test piece from the fiber-reinforced molded article based on JIS K7074 A method.
The appearance was visually confirmed. Appearance is judged by visually checking whether there are any defects such as deformation or non-uniform resin impregnation on the surface of the fiber-reinforced molded product, and if there are no defects, mark it as "〇", and if there are defects, mark it as "x". And so.
The thickness of each part of the fiber-reinforced molded product was measured by observing the cross section of the fiber-reinforced molded product using a digital microscope VHX-5000 (manufactured by Keyence Corporation). The thickness in Table 3 is the thickness near the center of the fiber-reinforced molded body.
The specific gravity was calculated from the weight of the fiber-reinforced molded product and the volume of the fiber-reinforced molded product. The volume of the fiber-reinforced molded product was calculated from the thickness and area of the fiber-reinforced molded product.

(2) Measurement results The measurement results are shown in Table 3.
The fiber-reinforced molded article of Example 1-10 satisfies the following requirements (a) and (b). On the other hand, the fiber-reinforced molded article of Comparative Example 1 does not meet requirement (a). In Comparative Example 1, which did not satisfy requirement (a), the viscosity of the resin was high, so the impregnating property of the resin was poor, and a uniform fiber-reinforced molded product could not be obtained. Moreover, the fiber-reinforced molded article of Comparative Example 2 does not satisfy requirement (b). In the fiber-reinforced molded article of Comparative Example 2, which did not meet requirement (b), the resin was not sufficiently cured, and deformation occurred during demolding.
In the fiber-reinforced molded article of Example 1-10 that satisfies requirements (a) and (b), by controlling the melting characteristics and curing characteristics of the solid thermosetting resin, the appearance can be improved by a simple method without using prepreg. A fiber-reinforced resin composite with excellent strength and weight reduction could be obtained. In addition, in the fiber-reinforced molded product of Example 1-10, a resin sheet (resin support sheet) can be produced by a simple method, and scattering of powder can be prevented, and organic solvents etc. can be used in the manufacturing process. Since no air pollution is used, the work environment is excellent and there are no air pollution problems.

- Requirement (a): The viscosity (minimum viscosity) at the curing reaction start temperature Tb° C. is 2,000 Pa·s or less.
- Requirement (b): The highest viscosity in the range of curing reaction start temperature Tb°C to 190°C is 1,000 Pa·s or more.

In addition, the fiber-reinforced molded article of Example 1-10 further satisfies the following requirement (c), so that the fiber base material can be sufficiently impregnated with the molten thermosetting resin, and the fibers have uniform physical properties. A reinforced molded body could be obtained.

- Requirement (c): 30≦(Tb-Ta)≦100 is satisfied.

The following inventions can also be understood from the above examples and comparative examples. The following descriptions of specific matters of the invention refer to the above descriptions as appropriate.
- A fiber-reinforced molded product in which a thermosetting resin is impregnated into a laminate in which a fiber base material and a sheet base material different from the fiber base material are laminated.

3. Effects of Examples According to the above examples, it was possible to obtain a fiber-reinforced resin composite that was excellent in appearance, strength, and weight reduction. In addition, the resin sheet can be produced using a simple method, preventing powder from scattering, and since no organic solvents are used in the manufacturing process, the work environment is excellent and there is no problem of air pollution. This was confirmed.

The present disclosure is not limited to the embodiments detailed above, and various modifications or changes are possible.

10...Fiber-reinforced molded body 11...Fiber base material 15...Resin sheet 30...Mold 31...Lower mold 32...Upper mold

Claims (7)

A method for producing a fiber-reinforced molded article, in which a fiber base material is integrated with the thermosetting resin of a resin sheet containing a thermosetting resin, the method comprising:
A method for producing a fiber-reinforced molded article, in which the fiber base material and the resin sheet are stacked and heated and compressed using a mold, and the thermosetting resin is impregnated into the fiber base material and cured.
The thermosetting resin has a viscosity of 59 Pa·s to 2,000 Pa·s at a curing reaction starting temperature Tb°C and a maximum viscosity of 8,768 Pa·s or more in the range of curing reaction starting temperature Tb°C to 190°C. can be,
A method for producing a fiber-reinforced molded article that satisfies any one of the following (1) to (4).
(1) The flexural modulus (JIS K7074 A method) is 66.1 GPa or more (2) The thermosetting resin contains cyanate resin (3) The fiber base material contains aramid fiber or basalt fiber ( 4) The thermosetting resin has a melting start temperature of Ta°C and a curing reaction start temperature of Tb°C.
The value of (Tb-Ta) satisfies 30≦(Tb-Ta)≦100 A method for producing a fiber-reinforced molded article, in which a fiber base material is integrated with the thermosetting resin of a resin sheet containing a thermosetting resin, the method comprising:
A method for producing a fiber-reinforced molded article, in which the fiber base material and the resin sheet are stacked and heated and compressed using a mold, and the thermosetting resin is impregnated into the fiber base material and cured.
The thermosetting resin has a viscosity of 2,000 Pa·s or less at a curing reaction starting temperature Tb°C and a maximum viscosity of 1,000 Pa·s or more in a range of curing reaction starting temperature Tb°C to 190°C,
A method for producing a fiber-reinforced molded article that satisfies the following (1).
(1) Flexural modulus (JIS K7074 A method) is 66.1 GPa or more A fiber base material selected from glass fiber, aramid fiber, basalt fiber, or carbon fiber and not impregnated with a thermosetting resin is integrated with the thermosetting resin of the resin sheet containing the thermosetting resin. Further, a method for manufacturing a fiber-reinforced molded article,
The resin sheet includes a sheet base material,
The thermosetting resin has a viscosity of 2,000 Pa·s or less at a curing reaction starting temperature Tb°C and a maximum viscosity of 1,000 Pa·s or more in a range of curing reaction starting temperature Tb°C to 190°C,
Satisfies any one of the following (1) to (2),
(1) The material of the sheet base material is rayon or polyester. (2) The sheet base material is a nonwoven fabric. The fiber base material and the resin sheet are overlapped and heated and compressed using a mold, and the A method for producing a fiber-reinforced molded article, which comprises impregnating the fiber base material with a curable resin and curing it. A fiber base material selected from glass fiber, aramid fiber, basalt fiber, or carbon fiber and not impregnated with a thermosetting resin is integrated with the thermosetting resin of the resin sheet containing the thermosetting resin. Further, a method for manufacturing a fiber-reinforced molded article,
The resin sheet includes a sheet base material,
The thermosetting resin has a viscosity of 59 Pa·s to 2,000 Pa·s at a curing reaction starting temperature Tb°C and a maximum viscosity of 8,768 Pa·s or more in the range of curing reaction starting temperature Tb°C to 190°C. can be,
Satisfies any one of the following (1) to (2),
(1) The material of the sheet base material is rayon, polyester, or carbon fiber. (2) The sheet base material is a nonwoven fabric or a fiber sheet. With the fiber base material and the resin sheet overlapped, a mold is used. A method for producing a fiber-reinforced molded article, which comprises heating and compressing the thermosetting resin to impregnate the fiber base material and curing the fiber base material. A resin sheet for producing a fiber-reinforced molded article,
Contains thermosetting resin,
A resin sheet that satisfies the following (1).
( 1 ) The thermosetting resin has a viscosity of 59 Pa·s to 2,000 Pa·s at the curing reaction starting temperature Tb°C, and a maximum viscosity of 8,768 Pa·s in the range of the curing reaction starting temperature Tb°C to 190°C. s or more,
The thermosetting resin has a melting start temperature of Ta°C and a curing reaction start temperature of Tb°C.
The value of (Tb-Ta) satisfies 30≦(Tb-Ta)≦100 A method for producing a resin sheet containing a thermosetting resin for producing a fiber-reinforced molded article, the method comprising:
A manufacturing method comprising the step of melting and supporting the thermosetting resin in powder form on a sheet base material made of rayon or polyester. A method for producing a resin sheet containing a thermosetting resin for producing a fiber-reinforced molded article, the method comprising:
A step of melting and supporting the thermosetting resin in powder form on a sheet base material made of rayon, polyester, or carbon fiber ,
The thermosetting resin is a group consisting of a mixed resin of phenol resin and epoxy resin, a mixed resin of phenol resin and cyanate resin, a mixed resin of epoxy resin and cyanate resin, and a mixed resin of phenol resin, epoxy resin, and cyanate resin. Manufacturing method that is more selected resin .

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