JP2005126557A - Molding material for and manufacturing method of fiber-reinforced resin composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a fiber-reinforced resin composite material which is good in appearance after the processings such as drilling and partial cutting and excellent in surface smoothness. <P>SOLUTION: The molding material for the fiber-reinforced resin composite material, which consists of a reinforcing fiber and a thermosetting resin composition, is arranged, at least on the surface of a portion where surface smoothness is required after the molding, with a prepreg which consists of the reinforcing fiber fabric having a basis weight of ≤160 g/m<SP>2</SP>and an aperture ratio of ≤4% and the thermosetting resin composition. The fiber-reinforced resin composite material is manufactured by using this molding material for the fiber-reinforced resin composite material and by conducting compression molding. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention provides a molding material for a fiber reinforced resin composite material (hereinafter referred to as FRP) which is easy to process such as drilling and partial cutting and has excellent surface smoothness, and an FR using this molding material.
The present invention relates to a method for producing P.

As a method for producing FRP, a method of heating and pressurizing a molding material for FRP made of prepreg or the like in a molding die is known. In particular, the production method by compression molding is an industrially useful method because the molding can be completed in a short time compared to a production method such as autoclave molding or vacuum bag molding (for example, Patent Documents 1, 2, and 3). reference).

By the way, it is not limited to compression molding, and after manufacturing FRP, the surface may be subjected to processing such as drilling or partial cutting for the purpose of making a joint with another molded product. in this case,
When the reinforcing fibers on the surface of the FRP are aligned in one direction, the reinforcing fibers cut at the time of processing are peeled off and fluttered, resulting in a problem that the appearance surface is deteriorated.
On the other hand, when the FRP surface is composed of a reinforced fiber fabric, it is difficult to produce a backlash or the like as compared with a case where the FRP surface is aligned in one direction. Therefore, when manufacturing FRP that requires processing such as drilling and partial cutting, a reinforced fiber woven prepreg is often used as a molding material for surface FRP.

However, when FRP is produced by compression molding using a reinforced fiber fabric prepreg on the surface,
The unevenness of the woven structure of the reinforcing fiber fabric appears as it is on the surface of the FRP, which causes the smoothness of the FRP surface to deteriorate. Therefore, if processing such as drilling or partial cutting is required for exterior materials of automobiles and railway vehicles where surface smoothness of the exterior is required, FRP is used for compression molding.
It was difficult to manufacture.
JP 61-43450 A JP 61-43451 A JP 61-43452 A

An object of the present invention is to obtain an FRP having a good appearance after processing such as drilling and partial cutting and excellent in surface smoothness by compression molding.

The gist of the present invention is that the basis weight is 160 g at least in a portion where surface smoothness is required after molding.
This is a molding material for FRP in which a prepreg composed of a reinforcing fiber woven fabric having a / m ² or less and an opening ratio of 4% or less and a thermosetting resin composition is disposed, and a method for producing FRP by compression molding the molding material.

By using the molding material for FRP of the present invention, the surface smoothness is excellent, and the appearance after processing such as drilling or partial cutting such as partial cutting or drilling is good, and FRP can be obtained by compression molding.

  Below, the molding material for FRP of this invention is demonstrated.

The molding material for FRP of the present invention comprises a reinforced fiber fabric having a basis weight of 160 g / m ² or less and an aperture ratio of 4% or less and a thermosetting resin composition at least in a portion where surface smoothness is required after molding. A prepreg is arranged.

(Reinforced fiber fabric)
The reinforcing fiber woven fabric may be a reinforcing fiber woven fabric having any woven structure such as plain weave, twill weave, silk weave and satin weave.
There is also no particular limitation on the type of reinforcing fiber constituting the reinforcing fiber fabric. Examples thereof include carbon fiber, aramid fiber, boron fiber, steel fiber, PBO fiber, high-strength polyethylene fiber, and glass fiber. In addition, a plurality of these reinforcing fibers may be used in the reinforcing fiber fabric.

In particular, carbon fiber is preferable because it is excellent in specific strength and specific elasticity. High-strength organic fibers such as aramid fibers and high-strength polyethylene fibers are preferable because impact resistance is imparted to the FRP.
It is preferable to use glass fibers because these reinforcing fibers are relatively inexpensive and excellent in strength.

The present invention is characterized by using a reinforcing fiber fabric having a basis weight of 160 g / m ² or less.

As described above, when the reinforcing fibers on the FRP surface constitute a woven fabric, irregularities of the woven structure of the reinforcing fiber woven fabric may appear on the FRP surface. Therefore, in order to solve such a problem, it is preferable to use a reinforced fiber fabric in which the unevenness of the woven structure is as small as possible.

Therefore, the present invention has found that FRP with higher surface smoothness can be obtained by reducing the unevenness of the woven structure of the reinforcing fiber fabric by using the reinforcing fiber fabric having a low basis weight. In particular, when the basis weight is 160 g / m ² or less, the surface centerline average roughness (Ra) of the portion where surface smoothness is required after molding can be 0.5 μm or less. Furthermore, the basis weight is 1
When it is 40 g / m ² , Ra can be 0.4 μm or less, which is preferable. The lower limit value of the basis weight is not particularly limited, but the reinforcing fiber woven fabric having a basis weight of less than 100 g / m ² is difficult to handle because the woven structure becomes too rough, and thus the basis weight is preferably set to 100 g / m ² or more.

The opening ratio of the reinforcing fiber fabric used for the prepreg of the present invention is required to be 4% or less. This is because by reducing the aperture ratio, a reinforced fiber fabric with less unevenness in the woven structure is obtained. In particular, 2% or less is preferable because the surface of the reinforcing fiber fabric is smooth.

The opening ratio is a value X (%) defined by the following equation when a region of area S1 is set on the surface of the reinforcing fiber fabric, and the total area of the openings of the reinforcing fibers in the area S1 is S2. is there.
X (%) = (S1 / S2) × 100
The total area S2 of the opening portion of the reinforcing fiber fabric can be measured by transmitting light from the lower portion of the reinforcing fiber fabric and subjecting the light transmission portion to image processing using an image processing sensor.

As a method for obtaining a reinforced fiber woven fabric having an opening ratio of 4% or less, the opening ratio may be set to 4% or less by applying a fiber opening treatment to the reinforcing fibers.
Any method can be used as a method for the fiber opening treatment of the reinforcing fiber fabric. For example, a method in which a steel ball collides with the surface of a reinforcing fiber fabric with a steel ball, a method of rubbing the surface of the reinforcing fiber fabric with a satin surface, a method of spraying water or air on the surface of the reinforcing fiber fabric, a roller or the like on the surface of the reinforcing fiber fabric Examples include a method of applying vibration, a method of electrostatic opening, and a method of ultrasonic opening. In particular, the method of causing the steel ball to collide with the surface of the reinforcing fiber fabric with the steel ball is preferable because post-treatment such as drying after the fiber opening is unnecessary.

(Thermosetting resin composition)
The type of thermosetting resin composition used for the prepreg is not particularly limited, and includes epoxy resin, phenol resin, unsaturated vinyl ester resin, unsaturated polyester resin, bismaleimide resin, BT resin, cyanate ester resin, benzoxazine resin, etc. Any thermosetting resin composition having a main component can be preferably used.

In particular, the epoxy resin has good adhesion to the reinforcing fiber, and can be particularly preferably used when obtaining FRP having excellent strength. Examples of the types of epoxy resins include bifunctional epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins. , Fluorene type epoxy resins and epoxy resins modified with any of these are used in polyfunctional epoxy resins having three or more functional groups, such as phenol novolac type epoxy resins, cresol type epoxy resins, tetraglycidyl diaminodiphenylmethane, triglycidyl aminophenol, tetra Glycidylamine type epoxy resin such as glycidylamine, glycidyl ether type epoxy such as tetrakis (glycidyloxyphenyl) ethane and tris (glycidyloxymethane) Both the resin and these either the modified epoxy resin can be suitably used.

When an epoxy resin and a curing agent containing a sulfur atom in the molecule are used in combination as the epoxy resin composition, the effect speed of the epoxy resin tends to be increased, and thus molding is completed in a short time. In particular, the sulfur atom content in the molecule is more preferably 7% by mass or more.
Examples of curing agents containing a sulfur atom in the molecule include 4,4′-diaminodiphenylsulfone, diaminodiphenylsulfide, bis (4- (4aminophenoxy) phenyl) sulfone, and bis (4- (3aminophenoxy). Phenyl) sulfone, 4,4′-diaminodiphenyl sulfide, o-triazine sulfone, and the like.

In addition to the curing agent, the thermosetting resin composition includes 3- (3,4-dichlorophenyl-
1,1-dimethylurea (DCMU) or 3-phenyl-N, N-dimethylurea (PDM)
Curing aids such as urea compounds such as U) and amine compounds such as dicyandiamide, thermoplastic resins such as polyvinyl formal and phenoxy resins, and flame retardants such as metal oxides and metal hydroxides can also be added.

(FRP molding material)
The part other than the prepreg composed of the reinforcing fiber fabric and the thermosetting resin composition (hereinafter referred to as the base material) disposed on the surface of the part requiring surface smoothness after molding of the molding material for FRP of the present invention. Any material may be used, but it is particularly preferable that it is composed of a reinforcing fiber and a thermosetting resin composition since strength improvement can be expected when FRP is used.
The type of reinforcing fiber used for the substrate is not particularly limited, and examples thereof include carbon fiber, aramid fiber, boron fiber, steel fiber, PBO fiber, high-strength polyethylene fiber, and glass fiber.
Further, the type of thermosetting resin composition used for the substrate is not particularly limited, and epoxy resin, phenol resin, unsaturated vinyl ester resin, unsaturated polyester resin, bismaleimide resin, BT resin, cyanate ester resin, benzo An example is a thermosetting resin composition mainly composed of an oxazine resin.
The shape of the substrate may be any form. For example, the unidirectional prepreg, the woven prepreg, the sheet molding compound, or a combination thereof may be used.
In the present invention, the surface of the portion requiring surface smoothness after molding may be the entire surface of the molding material for FRP or a part of the surface, and is determined according to the use of the FRP to be manufactured. it can.

(FRP manufacturing method)
The FRP of the present invention can be produced by compression-molding such a molding material for FRP and curing the thermosetting resin composition. The compression molding conditions of the present invention can be appropriately determined depending on the type and content of the thermosetting resin composition of the FRP molding material. In particular, if you want to complete the molding in a short time, adjust the temperature of the mold in advance to 120 ° C or higher before FRP
When the molding material is placed in a mold, the mold is clamped while maintaining the temperature of the mold, and molding is performed at a pressure of 2 MPa or more, the molding is completed in a short time. Among them, the molding conditions were set at a mold temperature of 14
If the temperature is 0 ° C. or higher and the molding pressure is 8 MPa, molding within 5 minutes becomes possible.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

<Thermosetting resin composition>
In this example, an epoxy resin composition obtained by mixing the following components at 80 ° C. until uniform was used as the thermosetting resin composition.
・ Epicoat 828 (bisphenol A type epoxy resin (liquid at room temperature), Japan Epoxy Resin Co., Ltd.) 50 parts by weight,
・ Epicoat 1009 (bisphenol A type epoxy resin (solid at room temperature), manufactured by Japan Epoxy Resins Co., Ltd.) 50 parts by mass,
Seikacure S (4,4′-diaminodimethylsulfone, manufactured by Wakayama Seika Co., Ltd.) 10
Part by mass / Omicure 94 (3-phenyl-1,1-dimethylurea, PTI Japan Ltd.) 5
Mass part · DICY15 (Dicyandiamide, manufactured by Japan Epoxy Resin Co., Ltd.) 5 parts by mass

<Manufacture of reinforced fiber fabric>
A plain fiber reinforced fiber fabric was woven using a rapier loom made by Tsuda Koma using Mitsubishi Rayon Co., Ltd. carbon fiber TR30S (3,000 filaments) as warp and weft. In the following examples, four different types of reinforcing fiber fabrics A, B, having a basis weight as described in Table 1,
C and D were obtained.

<Measurement of aperture ratio>
The aperture ratio of the reinforcing fiber fabric was measured as follows. First, an entire area S2 of the opening per 100 mm ² of the reinforcing fiber fabric is obtained by performing image processing on the surface of the reinforcing fiber fabric, which is manufactured by Keyence Co., Ltd., using the image processing apparatus CV-100. mm ² ) was measured, and the aperture ratio X was calculated by substituting S2 into the equation (1).
X (%) = (S2 (mm ² ) / 100 (mm ² )) × 100 (1)
The opening ratios of the reinforcing fiber fabrics A to D measured by this method are shown in Table 1.

<Measurement of surface centerline average roughness (Ra)>
The surface centerline average roughness (Ra) was measured using a Mitutoyo Surf Tester. The center 3 of the surface of the FRP under the measurement conditions of a cut-off value of 0.8 mm and a measurement length of 2.4 mm
Measurements were taken at the three locations and calculated as the average of these three locations.
<Example 1>

First, the opening treatment of the reinforcing fiber fabric A was performed using a steel ball collision opening device (steel ball speed: 1 mm / min). The fiber opening treatment was performed by causing a steel ball to collide with the reinforcing fiber fabric A while applying 150 ° C. hot air to the reinforcing fiber fabric A. Next, the reinforcing fiber fabric A (opening ratio: 2.9%) subjected to the fiber opening treatment is impregnated with two pairs of heating rolls heated to 75 ° C. in the form of a resin film of the epoxy resin composition. The content of the epoxy resin composition in the prepreg is 40
% Woven prepreg was obtained.
On the other hand, the resin film of the epoxy resin composition is carbon fiber TR50 manufactured by Mitsubishi Rayon Co., Ltd.
A sheet in which S was aligned in one direction with a fiber basis weight of 250 g / m ² was impregnated using two pairs of heating rolls heated to 75 ° C. to produce a unidirectional prepreg with a resin content of 30%. And
The unidirectional prepregs cut to 300 mm × 300 mm were alternately stacked so that the fiber orientation of the first layer was in the 0 ° direction and the next layer was in the 90 ° direction, thereby laminating 9 plies to obtain a laminate. Further, a woven fabric prepreg was bonded to one side of the laminate to obtain the FRP molding material of the present invention.

This molding material for FRP was placed in a molding die composed of an upper die and a lower die whose temperature was adjusted to 140 ° C. in advance. Immediately after placing the molding material for FRP, the upper die is lowered and the molding die is tightened. After applying a pressure of 8 MPa to the molding material for FRP for 5 minutes, the mold is opened and the temperature of the molding die is maintained at 140 ° C. While using the ejector pin provided in the mold,
A flat plate-shaped FRP having a thickness of 300 mm, a width of 300 mm, and a thickness of 2.2 mm was taken out. When this FRP was visually inspected, the surface appearance was clear. The R of this FRP
a was 0.31 μm, and a very smooth product was obtained.
<Example 2>

FRP was obtained in the same manner as in Example 1 except that the reinforcing fiber fabric was changed to the reinforcing fiber fabric B. The opening ratio of the reinforcing fiber fabric B subjected to the fiber opening treatment was 2%.
When this FRP was visually inspected, the surface appearance was clear. Further, Ra of this FRP was 0.36 μm, and a smooth one was obtained.
<Example 3>

FRP was obtained in the same manner as in Example 1 except that the reinforcing fiber fabric was changed to the reinforcing fiber fabric C. The opening ratio of the reinforcing fiber fabric C subjected to the fiber opening treatment was 0.02%.
When this FRP was visually inspected, the surface appearance was clear. Moreover, Ra of this FRP was 0.40 μm, and a smooth one was obtained.
<Comparative Example 1>

FRP was obtained in the same manner as in Example 1 except that the reinforcing fiber fabric was changed to the reinforcing fiber fabric D. The opening ratio of the reinforcing fiber fabric D subjected to the fiber opening treatment was 0.01%.
The Ra of FRP was 0.55 μm, which was coarser than the molded product obtained in each example, and streaky defects were also observed in visual inspection.
<Comparative example 2>

FRP was obtained in the same manner as in Example 3 except that the reinforcing fiber fabric C was used without being subjected to fiber opening treatment. The opening ratio of the reinforcing fiber fabric C subjected to the fiber opening treatment was 5%. When visual inspection was performed on this FRP, a slight defect occurred in the surface appearance. The average surface roughness Ra of the FRP was 0.47 μm.

Since FRP obtained by the production method of the present invention is excellent in surface smoothness, it can be used for a member that requires smoothness and requires processing on the surface. Specifically, motorcycle frames, cowls, fenders and other motorcycles, doors, bonnets, tailgates, side fenders, side panels, fenders, energy absorbing members, trunk lids, hardtops, side mirror covers, spoilers, diffusers, ski carriers , Engine cylinder covers, engine hoods, chassis, air spoilers, propeller shafts and other automotive parts applications, leading vehicle noses, roofs, side panels, doors, bogie covers, side skirts and other vehicle skins, luggage racks, seats Such as railway vehicles, interiors, wing inner panels, outer panels, roofs, floors, aero parts such as side skirts for automobiles and motorcycles, window frames, luggage racks, seats, Air panels, wings, propellers, fuselage aircraft applications, notebook PCs, mobile phone case applications, flat speaker panels, speaker cones and other acoustic product applications, golf heads, faceplates, snowboards, surf boards, protector sports Goods use is mentioned.

Claims (6)

A fiber reinforced resin in which a prepreg composed of a reinforced fiber fabric having a basis weight of 160 g / m ² or less and an aperture ratio of 4% or less and a thermosetting resin composition is disposed at least on the surface of a portion requiring surface smoothness after molding. Molding material for composite materials. The molding material for fiber-reinforced resin composite material according to claim 1, wherein the reinforcing fiber is at least one kind of reinforcing fiber selected from the group consisting of carbon fiber, glass fiber, aramid fiber and high-strength polyethylene fiber. The molding material for fiber-reinforced resin composite materials according to claim 1 or 2, wherein the thermosetting resin composition is an epoxy resin composition. The molding material for fiber reinforced resin composite materials according to claim 3, wherein the epoxy resin composition is an epoxy resin composition containing an epoxy resin and a curing agent having a sulfur atom in the molecule. The manufacturing method of the fiber reinforced resin composite material which compression-molds the molding material for fiber reinforced resin composite materials as described in any one of Claims 1-4, and hardens | cures a thermosetting resin composition. Compression molding is a compression molding in which a molding material for fiber reinforced resin composite material is placed in a mold that has been conditioned to 120 ° C or higher in advance, and the mold is clamped to apply a pressure of 2 MPa or more to the molding material for fiber reinforced resin composite material. A method for producing a fiber-reinforced resin composite material according to claim 5.