JP6413851B2 - Substrate for fiber reinforced plastic molding and fiber reinforced plastic molding - Google Patents

Description

  The present invention relates to a substrate for a fiber-reinforced plastic molded body and a fiber-reinforced plastic molded body. In addition, this invention relates also to the manufacturing method of the base material for fiber reinforced plastic moldings, and the manufacturing method of a fiber reinforced plastic molding.

  Non-woven fabric (also called fiber reinforced plastic molding base material) containing reinforcing fibers such as carbon fiber and glass fiber is heated and pressurized, and the molded fiber reinforced plastic molding is already used in sports, leisure goods, aircraft materials, etc. It is used in various fields. As a method of molding a fiber reinforced plastic molded body, a method of impregnating a base material for a fiber reinforced plastic molded body composed of reinforced fibers with a thermosetting resin or a thermoplastic resin and heat-press molding, A method for heat-pressing a substrate for a fiber-reinforced plastic molded body composed of a thermosetting resin or a thermoplastic resin is known.

  Carbon fiber or glass fiber is used as the reinforcing fiber. Such reinforcing fibers serve to increase the strength of the fiber-reinforced plastic molded body. Further, by orienting reinforcing fibers in a specific direction in a substrate for fiber-reinforced plastic molded bodies, it is performed to give directionality to the strength of the fiber-reinforced plastic molded bodies (for example, Patent Documents 1 to 4). ). In Patent Documents 1 to 4, a fiber reinforced plastic having improved mechanical strength in one direction by adjusting the orientation direction of the reinforcing fibers in the planar direction of the base material for a fiber reinforced plastic molded body containing reinforcing fibers and a thermoplastic resin. It has been proposed to form a shaped body.

Japanese Patent Laid-Open No. 5-44188 JP-A-4-208405 JP-A-4-208406 JP-A-4-208407

  An object of this invention is to provide the base material for fiber reinforced plastic moldings which can improve the bending strength of a fiber reinforced plastic molding.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have identified a fiber orientation parameter (fp) in the thickness direction in a base material for a fiber-reinforced plastic molded body containing reinforcing fibers and a binder component. It was found that a substrate for a fiber reinforced plastic molded body capable of improving the bending strength of the fiber reinforced plastic molded body can be obtained by setting the range.
Specifically, the present invention has the following configuration.

[1] A base material for a fiber-reinforced plastic molded body containing reinforcing fibers and a binder component, and an absolute value of a fiber orientation parameter (fp) in the thickness direction in the base material for a fiber-reinforced plastic molded body is 0.5 to 1 A base material for a fiber-reinforced plastic molded body, characterized by being 0.0.
[2] The substrate for fiber reinforced plastic molding according to [1], wherein the absolute value of the fiber orientation parameter (fp) in the plane direction in the substrate for fiber reinforced plastic molding is 0.18 to 1.0.
[3] The fiber-reinforced plastic molded article substrate according to [1] or [2], wherein the reinforcing fibers are carbon fibers.
[4] The fiber-reinforced plastic molding according to any one of [1] to [3], wherein the content of the binder component is 0.1 to 10% by mass with respect to the total mass of the substrate for fiber-reinforced plastic molded body. Body substrate.
[5] The fiber-reinforced plastic molded article substrate according to any one of [1] to [4], wherein the fiber length of the reinforcing fiber is 10 mm or more.
[6] It includes a step of wet papermaking a slurry in which reinforcing fibers and a binder component are mixed. The wet papermaking step is a step of making a paper using an inclined paper machine, and the wire of the inclined paper machine is a jet A method for producing a substrate for a fiber-reinforced plastic molded article, wherein the wire ratio is 0.98 or less.
[7] The method for producing a base material for a fiber-reinforced plastic molded body according to [6], wherein the wire of the inclined type paper machine runs such that the jet wire ratio is 0.90 or less.
[8] The method for producing a substrate for a fiber-reinforced plastic molded body according to [6] or [7], wherein the dispersion medium of the slurry has a viscosity at 25 ° C. of 0.8 to 4.0 mPa.
[9] A base material for a fiber-reinforced plastic molded body produced by the production method according to any one of [6] to [8].
[10] A method for producing a fiber-reinforced plastic molded body using the substrate for fiber-reinforced plastic molded body according to any one of [1] to [5] and [9], wherein the fiber-reinforced plastic molded body is used. A step of impregnating a base material with a resin to obtain a base material for a resin-containing fiber-reinforced plastic molded body, or a step of obtaining a base material for resin-containing fiber-reinforced plastic molded body by laminating a resin; And a step of pressing the material. A method for producing a fiber-reinforced plastic molded article.
[11] A fiber-reinforced plastic molded article produced by the production method according to [10].

  ADVANTAGE OF THE INVENTION According to this invention, the base material for fiber reinforced plastic moldings which can improve the bending strength of a fiber reinforced plastic molding can be obtained.

FIG. 1 is a conceptual diagram of an example of a base material for a fiber-reinforced plastic molded body of the present invention. FIG. 2 is a conceptual diagram of a test piece for cross-sectional observation for measuring the fiber orientation parameter of the substrate for fiber-reinforced plastic molded body of the present invention.

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

(Substrate for fiber reinforced plastic molding)
The present invention relates to a base material for a fiber-reinforced plastic molded body containing reinforcing fibers and a binder component. In the base material for fiber-reinforced plastic molded bodies of the present invention, the absolute value of the fiber orientation parameter (fp) in the thickness direction is 0.5 to 1.0.

  FIG. 1 is a conceptual diagram of a substrate for a fiber-reinforced plastic molded body of the present invention. As shown in FIG. 1, the substrate 10 for a fiber-reinforced plastic molded body of the present invention includes a reinforcing fiber 20 as a main component. Here, the main constituent component refers to a component of 80% by mass or more with respect to the total mass of the substrate 10 for a fiber-reinforced plastic molded body. That is, the content of the reinforcing fiber 20 is 80% by mass or more with respect to the total mass of the substrate 10 for a fiber-reinforced plastic molded body. The substrate 10 for fiber-reinforced plastic molded body includes a binder component 30. The binder component 30 is a binding component present at the contact point of the reinforcing fiber 20. Further, the binder component 30 is present at, for example, the contact points between almost all the reinforcing fibers 20. Furthermore, the binder component 30 may be present in a portion other than the contact point between the reinforcing fibers 20. In FIG. 1, the presence of the binder component 30 is illustrated so as to be understood, but actually, it may be a minute binding component that cannot be visually recognized. The binder component 30 may be a fiber having the same shape as the reinforcing fiber 20.

  In the present specification, the fiber orientation parameter (fp) is a parameter that represents the orientation state of the reinforcing fibers in the substrate for a fiber-reinforced plastic molded body. The fiber orientation parameter (fp) is a parameter that represents the fiber orientation distribution with a numerical value of −1.0 to 1.0. When fp = −1.0 and fp = 1.0, the reinforcing fiber is oriented in one direction. This means that when fp = 0.0, the reinforcing fibers are arranged completely at random.

  In the base material for fiber-reinforced plastic molded bodies according to the prior art, it is clear from the examination of the present inventors that there may be variations in the orientation of the reinforcing fibers in the thickness direction of the base material for fiber-reinforced plastic molded bodies. It became. Furthermore, there is a possibility that the bending strength of the fiber reinforced plastic molded body formed from the fiber reinforced plastic molded body base material may decrease due to variation in the orientation of the reinforcing fibers in the thickness direction of the fiber reinforced plastic molded body base material. The present inventors made clear. The present invention controls the fiber orientation parameter (fp) in the thickness direction of the substrate for fiber-reinforced plastic molded bodies based on such knowledge.

In the present invention, the absolute value of the fiber orientation parameter (fp) in the thickness direction in the substrate for fiber-reinforced plastic molded body may be 0.5 to 1.0, and is 0.6 to 1.0. Preferably, it is 0.7 to 1.0, more preferably 0.8 to 1.0, and particularly preferably 0.9 to 1.0. By setting the absolute value of the fiber orientation parameter (fp) in the thickness direction within the above range, the orientation of the reinforcing fibers in the thickness direction can be made constant, and the bending strength of the fiber-reinforced plastic molded body can be improved. A possible fiber-reinforced plastic molded body substrate can be obtained. Moreover, since the base material for fiber reinforced plastic moldings of the present invention has the above-described configuration, the bending strength in the MD direction (flow direction of the papermaking line) of the fiber reinforced plastic moldings is particularly enhanced.
In addition, the fiber orientation parameter (fp) in the thickness direction of the base material for fiber reinforced plastic molded body can be controlled by appropriately selecting, for example, a method for manufacturing the base material for fiber reinforced plastic molded body.

When measuring the fiber orientation parameter (fp) in the thickness direction of a base material for a fiber reinforced plastic molded body, an epoxy resin for embedding generally used for observation of an electron microscope on the base material for a fiber reinforced plastic molded body A test piece for cross-sectional observation is prepared by impregnating with the like. The reason why the epoxy resin for embedding is impregnated is to prevent the orientation direction of the fibers from being changed by the shearing force at the time of cutting when the cross section described later is cut out. The embedding resin is preferably a resin having sufficient strength and hardness that can withstand shearing force, such as an epoxy resin or a styrene resin. However, in the present invention, by using an epoxy resin, a fiber orientation parameter (fp) in the thickness direction is used. ). Examples of the embedding resin include Aronix LCA D-800 manufactured by JEOL Ltd. In addition, the thermosetting type resin and the resin that generates heat when cured, the adhesive strength between the reinforcing fibers of the binder in the substrate for fiber reinforced plastic molded bodies is reduced by the heat during curing, and the angle of the reinforcing fibers changes. Therefore, it is preferable to use a resin that does not become a heat source during curing, such as a photo-curing type epoxy resin such as ultraviolet rays.
As a resin embedding method, a method generally used in electron microscope observation or optical microscope observation can be employed. Specifically, the substrate for fiber-reinforced plastic molded body is cut into a width of 5 mm and a length of 10 mm, and the above-described embedding epoxy resin is dropped and impregnated until at least the entire surface of the test piece is covered and cured. . Moreover, dripping of the epoxy resin for embedding can be performed using a dropper etc., for example.

  FIG. 2 is a conceptual diagram of a cross-sectional observation test piece obtained by impregnating a substrate for fiber reinforced plastic molding with an ultraviolet curing epoxy resin for embedding. As shown in FIG. 2A, the cross-section observation test piece 50 includes reinforcing fibers 20 constituting the substrate 10 for fiber-reinforced plastic molded body and an embedding epoxy resin 40. In the cross-section observation test piece 50, the positional relationship and shape of the reinforcing fibers 20 are the same as those in the substrate 10 for fiber-reinforced plastic molded body, and are embedded so as to maintain the positional relationship and shape of the reinforcing fibers 20. An epoxy resin 40 is present.

When observing the fiber orientation in the thickness direction, using a slice master HS-1 manufactured by JASCO Corporation, a test piece for cross-sectional observation having a width of 0.4 mm was cut out from the cured product, and the thickness of the obtained test piece was measured. The cross section in the direction is observed with an optical microscope. For the optical microscope, a microscope manufactured by Keyence Corporation is used, and the fibers are observed with transmitted light after enlarging the magnification so that the monofilament can be visually recognized. In the present embodiment, for example, the magnification can be selected from 300 times, 600 times, and 800 times. Here, for example, observation can be performed with a focus on a portion having a depth of 10 μm or more from each of the observation surface and the opposite surface of the test piece. In addition, you may cut out a test piece using a microtome.
In the present invention, by embedding with an epoxy resin and cutting out a cross section in the thickness direction, it is possible to prevent the fiber angle from being changed by the shearing force at the time of cutting. Moreover, since the distinction between the embedding resin and the fiber can be clarified by observing with transmitted light, the angle can be easily measured.

The orientation direction of the reinforcing fiber is, for example, the major axis direction of the reinforcing fiber. Moreover, the reinforcing fiber may be confirmed to be elliptical in the cross section in the thickness direction. When the reinforcing fiber is confirmed to be elliptical, the major axis direction of the ellipse is taken as the fiber orientation direction. The orientation angle θi of the reinforcing fiber is an angle formed by the orientation direction (orientation line) of the selected reinforcing fiber with respect to the reference line. In the present invention, the cross section in the thickness direction of the test piece is observed with an optical microscope under the above conditions, and a continuous measurement area of 1.5 mm ² arbitrarily selected from the above cross section is observed. The orientation angle θi of all the fibers that can be visually recognized (the number of fibers is n) is measured. For the orientation angle θi, an angle in a clockwise direction with respect to the reference line is measured and set to an angle of 0 ° or more and less than 180 °.

The fiber orientation parameter in the thickness direction (fp, hereinafter also referred to as fp value) can be calculated from the orientation angle θi measured by the above method using the following formula (1).
fp = 2 × Σ (cos ² θ _i / n) −1 Formula (1)
Here, θ _i is the orientation angle (i = 1 to n) of the selected reinforcing fibers with respect to the reference line.

Here, the reference line can be determined by the following method.
When setting the reference line, first, the temporary reference line p is selected, and the angles of all the visible fibers existing in the measurement region are measured. In this case, the angle between the temporary reference line p and each fiber is represented by α (p) _i (i = 1 to n).
The fiber orientation parameter (fp (p)) when using the temporary reference line p can be calculated using the following formula.
fp (p) = 2 × Σ (cos ² α (p) _i / n) −1
(I = 1, 2, 3,..., N)
Next, the temporary reference line p (p _{+ z} , p _−z (z = 1 to 90)) obtained by rotating the temporary reference line p by ± 1 ° to ± 90 ° is taken, and the temporary reference line p _{+ z} And the angle of the temporary reference line p _-z and n fibers. The angles in this case are represented by α (p _{+ z} ) _i and α (p _−z ) _i (i = 1 to n).
The rotated temporary reference line (p _{+ z} , p- _z (z = 1 to 90)) and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber can be calculated using the following formula.
fp (p ± _z ) = 2 × Σ (cos ² α (p ± _z ) _i / n) −1
(I = 1, 2, 3,..., N)
In this way, the temporary reference line set when the maximum value is obtained among the obtained fp (p) value and fp (p ± _z ) value can be used as the reference line P. The fiber orientation parameter calculated from the reference line P thus determined can be a fiber orientation parameter (fp) in the thickness direction.

FIG. 2B is a conceptual cross-sectional view in which the cross-sectional observation test piece 50 shown in FIG. 2A is cut out in the BB ′ direction and the thickness direction is the vertical direction. The BB ′ direction is preferably a direction parallel to the direction in which most of the fibers are oriented.
In FIG.2 (b), the reference line determined by said method is a dotted line represented by P, and the orientation of each reinforcement fiber is represented by the dotted line of Q and R, respectively. In addition, in FIG.2 (b), the dotted line made into P 'is a line parallel to a reference line, and is for demonstrating clearly the angle which the reference line P and the orientation line (Q and R) of each reinforcement fiber make. It is an auxiliary line. In FIG. 2B, since the angle formed by P ′ and Q (orientation angle θ ₁ ) is 0 °, P ′ and Q overlap. The angle formed by P ′ and R (orientation angle θ ₂ ) is represented as θ ₂ . In this way, θ ₁ to θ _n are measured.

In addition, as a part which measures a fiber orientation parameter (fp), a temporary reference line, and a fiber orientation parameter (fp (p ± _z )) of a reinforcing fiber, avoid the end of the cross section in the thickness direction of the test piece for cross section observation, The vicinity of the center is preferable. Specifically, it is preferable to avoid the region up to 5% (5% with respect to the thickness of the cross-sectional observation test piece) from the both ends of the cross-section observation test piece in the thickness direction to be the measurement region.

  In the present invention, the fiber orientation parameter (fp) in the thickness direction being in the above range means that the fibers are oriented so that the angle formed with the center plane of the fiber-reinforced plastic molded body of the reinforcing fibers is small. Here, the center surface of the base material for fiber-reinforced plastic molded body is formed by connecting the midpoint of the first surface and the average surface of the second surface of the base material for fiber-reinforced plastic molded body. It is a plane. Note that the midpoint of the average surface of the first surface and the average surface of the second surface refers to the midpoint of the shortest distance between the specific point of the first surface and the second surface. In addition, the average surface of each surface means a surface that passes through the average height of the concave and convex portions when the surface has an uneven shape, and each average surface is It refers to the surface.

  Moreover, it is preferable that the absolute value of the fiber orientation parameter (fp) of the plane direction in the base material for fiber reinforced plastic moldings is 0.18-1.0. The absolute value of the fiber orientation parameter (fp) in the planar direction in the substrate for fiber-reinforced plastic molded body is more preferably 0.25 to 1.0, further preferably 0.3 to 1.0. 0.6 to 1.0 is particularly preferable. That is, in the base material for fiber-reinforced plastic molded body of the present invention, it is preferable that the reinforcing fibers have a uniform orientation in the plane direction in addition to the uniform orientation in the thickness direction.

The measurement of the fiber orientation parameter in the plane direction in the substrate for fiber-reinforced plastic molded body can be performed without particularly processing such as resin embedding. Specifically, a base material for a fiber reinforced plastic molded body cut into a length of 3 cm and a width of 3 cm is placed on a slide glass, a slide glass is further placed on the top, and a normal reflected light is measured using a microscope. Can be observed.
In the present invention, one surface of a test piece sandwiched between slide glasses is observed with an optical microscope. For the optical microscope, a microscope manufactured by Keyence Co., Ltd. is used, and the fibers are observed with reflected light by expanding the magnification so that the monofilament can be visually recognized or by using both reflected light and transmitted light. In the present embodiment, for example, the magnification can be selected from 300 times, 600 times, and 800 times. Thereby, a continuous measurement area of 2.0 mm ² arbitrarily selected on one surface is observed, and all the fibers (number of fibers is m) that can be visually recognized existing in this measurement area. The orientation angle θi is measured. For the orientation angle θi, an angle in a clockwise direction with respect to the reference line is measured and set to an angle of 0 ° or more and less than 180 °. The fiber orientation parameter (fp, hereinafter also referred to as fp value) can be calculated from the orientation angle θi measured by the above method using the following formula (2).
fp = 2 × Σ (cos ² θ _i / m) −1 Formula (2)
However, i = 1 to m.
And it measures similarly about an opposite surface, calculates | requires the average value of one surface and an opposite surface, and makes this a fiber orientation parameter (fp) of a plane direction. Note that the measurement area on the opposite side of the measurement area on one surface is, for example, an area overlapping in a plan view. In any observation of one surface and the opposite surface, for example, it is possible to observe with focusing on a portion having a depth of 10 μm or more from each of the one surface and the opposite surface.

The reference line for measuring the fiber orientation parameter in the plane direction can be determined by the following method.
When setting the reference line, first, the temporary reference line p is selected, and the angles of all the visible fibers m existing in the measurement region are measured. In this case, the angle between the temporary reference line p and each fiber is represented by α (p) _i (i = 1 to m).
The fiber orientation parameter (fp (p)) when using the temporary reference line p can be calculated using the following formula.
fp (p) = 2 × Σ (cos ² α (p) _i / m) −1
(I = 1, 2, 3,..., M)
Next, the temporary reference line p (p _{+ z} , p _−z (z = 1 to 90)) obtained by rotating the temporary reference line p by ± 1 ° to ± 90 ° is taken, and the temporary reference line p _{+ z} And the angle of the provisional reference line p _-z and m fibers are calculated. The angles in this case are represented by α (p _{+ z} ) _i and α (p _−z ) _i (i = 1 to m).
The rotated temporary reference line (p _{+ z} , p- _z (z = 1 to 90)) and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber can be calculated using the following formula.
fp (p ± _z ) = 2 × Σ (cos ² α (p ± _z ) _i / m) −1
(I = 1, 2, 3,..., M)
In this way, the temporary reference line set when the maximum value is obtained among the obtained fp (p) value and fp (p ± _z ) value can be used as the reference line P. The fiber orientation parameter calculated from the reference line P thus determined can be a fiber orientation parameter (fp) in the plane direction.

  When the orientation of the reinforcing fibers in the plane direction is a fixed direction, the reinforcing fibers may be oriented in any direction in the plane direction of the base material for the fiber-reinforced plastic molded body, but the base material for the fiber-reinforced plastic molded body It is preferably oriented in the MD direction (flow direction of the papermaking line).

  When the orientation of the reinforcing fiber in the thickness direction and the planar direction is a fixed direction, the bending strength in one direction is increased in the fiber-reinforced plastic molded body obtained by molding the substrate for a fiber-reinforced plastic molded body. In particular, when the reinforcing fibers are oriented in the MD direction, the strength in the MD direction is increased in the fiber-reinforced plastic molded body.

Further, in the fiber reinforced plastic molded body molded from the substrate for fiber reinforced plastic molded body of the present invention, the bending strength in the first direction of the fiber reinforced plastic molded body and the bending in the second direction orthogonal to the first direction. It is also preferable that the intensity ratio is 3 or more. The strength ratio of bending strength is preferably 4 or more, and more preferably 5 or more. In addition, the 1st direction means the orientation direction of the reinforced fiber in the plane direction of the base material for fiber reinforced plastic moldings, and the 2nd direction means the direction orthogonal to the orientation direction of the reinforced fiber in a plane direction. In the present invention, when the reinforcing fibers are oriented in the MD direction, the first direction is the MD direction, and the second direction is the CD direction (a direction orthogonal to the flow direction of the papermaking line).
Thus, in the base material for fiber reinforced plastic molded bodies, when the thickness direction and the plane direction orientation of the reinforced fibers are constant, the strength in a specific direction is increased in the fiber reinforced plastic molded body. Such a fiber reinforced plastic molded article is preferably used for a structural part that requires mechanical strength in one direction used in automobiles, aircrafts, and the like.

  In the base material for a fiber-reinforced plastic molded body of the present invention, the blending ratio of the reinforcing fibers is preferably 80 to 99% by mass. By setting the blending ratio of the reinforcing fibers within the above range, it is possible to increase the number of fibers oriented in a specific direction in the fiber-reinforced plastic molded body. This shortens the distance between the reinforcing fibers, increases the packing density of the reinforcing fibers after the heat and pressure molding, and can effectively increase the strength of the fiber-reinforced plastic molded body.

The basis weight of fiber-reinforced plastic molded body substrate of the present invention, for example, is preferably 8~600g / m ^2, and more preferably 10 to 500 g / m ^2. By setting it as the said upper limit or less, the improvement of the drying efficiency in the drying process of the base material for fiber reinforced plastic molded objects and the orientation of the fiber of a thickness direction can further be improved. On the other hand, by setting it to the above lower limit value or more, it is possible to more reliably suppress paper breaks in the manufacturing process of the base material for a fiber-reinforced plastic molded body, thereby improving the production efficiency.

(Reinforced fiber)
The base material for fiber-reinforced plastic molded bodies of the present invention contains reinforcing fibers. Examples of the reinforcing fiber include glass fiber, carbon fiber, aramid fiber, and PBO (polyparaphenylene benzoxazole) fiber. These reinforcing fibers may use only 1 type and may use multiple types. Among these, carbon fibers are preferably used as the reinforcing fibers.

  For example, when a fiber such as carbon fiber or glass fiber is used as the reinforcing fiber, the fiber-reinforced plastic molded body is obtained by heating and pressing at the melting temperature of the thermoplastic fiber contained in the base material for the fiber-reinforced plastic molded body. It becomes possible to form. Further, when a fiber such as aramid is used as the reinforcing fiber, the wear resistance can be improved.

  The fiber length of the reinforcing fibers is preferably 3 mm or more, more preferably 10 mm or more, further preferably 15 mm or more, and particularly preferably 20 mm or more. The fiber length of the reinforcing fiber can be 50 mm or more. The fiber length of the reinforcing fiber is preferably 150 mm or less, more preferably 100 mm or less, and further preferably 75 mm or less. In addition, in this specification, the fiber length of a reinforced fiber is a mass average fiber length, and is the average value of the fiber length measured about 100 fibers. By setting the mass average fiber length of the reinforcing fibers within the above range, the reinforcing fibers can be prevented from falling off from the substrate for the fiber-reinforced plastic molded body, and the dispersibility of the fibers is good and the strength is increased. An excellent fiber-reinforced plastic molded body can be formed.

  In addition, although the fiber diameter of a reinforced fiber is not specifically limited, In the case of carbon fiber, it is preferable that a fiber diameter is 5-25 micrometers. In addition, in this specification, the fiber diameter of a reinforced fiber is a number average fiber diameter, and is an average value of the fiber diameter which measured the fiber diameter of 100 fibers.

(Carbon fiber)
Carbon fibers are preferably used as the reinforcing fibers. As the carbon fibers, carbon fibers such as polyacrylonitrile (PAN), petroleum / coal pitch, rayon, and lignin can be used. These carbon fibers may be used alone or in combination of two or more. Of these carbon fibers, polyacrylonitrile (PAN) -based carbon fibers are preferably used from the viewpoint of productivity and mechanical properties on an industrial scale.

  The fiber length of the carbon fiber is preferably 3 mm or more, more preferably 10 mm or more, further preferably 15 mm or more, and particularly preferably 20 mm or more. In addition, the fiber length of carbon fiber can also be 50 mm or more. The fiber length of the reinforcing fiber is preferably 150 mm or less, more preferably 100 mm or less, and further preferably 75 mm or less. In addition, in this specification, the fiber length of a carbon fiber is a mass average fiber length, and is the average value of the fiber length measured about 100 fibers.

  The single fiber strength of the carbon fiber is preferably 4500 MPa or more, more preferably 4600 MPa or more, and further preferably 4700 MPa or more. Single fiber strength refers to the tensile strength of a monofilament. When such a carbon fiber is used, the bending strength is greatly improved by a synergistic effect with the fiber orientation effect of the reinforcing fiber described above. The single fiber strength can be measured according to JIS R7601 “Test method for carbon fiber”.

(Reinforcing fiber shape)
The reinforcing fibers are preferably chopped strands cut to a certain length. The dispersibility in the base material for fiber reinforced plastic moldings can be improved by making a reinforced fiber into such a form. The cross-sectional shape of the reinforcing fiber is not limited to a circular shape, and an elliptical shape or a modified cross-sectional shape can also be used. In addition, as a reinforcing fiber, a some raw material and shape can also be used together.

(Binder component)
The base material for fiber-reinforced plastic molded articles of the present invention contains a binder component. The content of the binder component is preferably 0.1 to 10% by mass, more preferably 0.3 to 10% by mass, with respect to the total mass of the base material for fiber-reinforced plastic molded body. It is more preferable that it is 4-9 mass%, and it is especially preferable that it is 0.5-8 mass%. By making the content of the binder component within the above range, the strength of the base material for fiber-reinforced plastic molded body can be increased, and the base for fiber-reinforced plastic molded body does not cause delamination even after repeated cutting processes. A material can be obtained. For this reason, the base material for fiber reinforced plastic moldings of this invention is excellent in handling property. Moreover, the intensity | strength of the fiber reinforced plastic molded object shape | molded from the base material for fiber reinforced plastic molded objects can also be raised by making the content rate of a binder component into the said range.

  As binder components, polyester resins such as polyethylene terephthalate and modified polyethylene terephthalate used for general nonwoven fabric production, acrylic resins, styrene- (meth) acrylate copolymer resins, urethane resins, PVA resins, various starches , Cellulose derivative, sodium polyacrylate, polyacrylamide, polyvinylpyrrolidone, acrylamide-acrylic ester-methacrylic ester copolymer, styrene-maleic anhydride copolymer alkali salt, isobutylene-maleic anhydride copolymer alkali salt, Polyvinyl acetate resin, styrene-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, styrene-butadiene- (meth) acrylic acid ester copolymer, etc. can be used.

The binder component may contain a copolymer including at least one of a repeating unit derived from a methyl (meth) acrylate-containing monomer and a repeating unit derived from an ethyl (meth) acrylate-containing monomer. In this case, the binder component preferably contains a copolymer containing at least one of a repeating unit derived from a methyl methacrylate-containing monomer and a repeating unit derived from an ethyl methacrylate-containing monomer. These monomers may be copolymerized with other monomers such as styrene, vinyl acetate, acrylamide and the like.
In the present invention, “(meth) acrylate” means containing both “acrylate” and “methacrylate”, and “(meth) acrylic acid” means “acrylic acid” and “methacrylic acid”. Is meant to include both.

Furthermore, in this invention, a polyester resin and a modified polyester resin can also be used as a binder component. Especially as a polyester resin, a polyethylene terephthalate (PET) can be mentioned as a preferable example. The modified polyester resin is not particularly limited as long as the melting point is lowered by modifying the polyester resin, but modified polyethylene terephthalate is preferable. As the modified polyethylene terephthalate, copolymerized polyethylene terephthalate (coPET) is preferable, and examples thereof include urethane-modified copolymerized polyethylene terephthalate. The polyester resin is preferably used because it is compatible with the thermoplastic fiber of the present invention at the time of heating and melting, so that it is difficult to impair the function of heat and resin even after cooling.
The copolymerized polyethylene terephthalate preferably has a melting point of 140 ° C. or lower, more preferably 120 ° C. or lower. Moreover, you may use the modified polyester resin as described in Japanese Patent Publication No. 1-30926. As a specific example of the modified polyester resin, a trade name “Melty 4000” (a fiber in which all fibers are copolymerized polyethylene terephthalate) manufactured by Unitika Ltd. is particularly preferable. Moreover, as a binder fiber of a core-sheath structure, a product name “Melty 4080” manufactured by Unitika, a product name “N-720” manufactured by Kuraray, or the like can be suitably used.

  In this invention, the absolute value of the fiber orientation parameter (fp) of the thickness direction in the base material for fiber reinforced plastic molded objects is 0.5-1.0. In such a fiber-reinforced plastic molded body substrate, the density of reinforcing fibers can be increased, and the number of fibers that contribute to increasing the bending strength of the molded body using the molded body substrate increases. , The molded body can be strengthened. Furthermore, since the intersections of the reinforcing fibers are increased, even when the amount of the binder component added is decreased, sufficient process strength can be obtained at the time of manufacturing the fiber-reinforced plastic molded body substrate.

  The binder component is a binding component present at the contact point of the reinforcing fiber, and its shape is not particularly limited. The shape of the binder component can be, for example, a particle shape or a fiber shape, and is preferably a fiber shape.

  When the shape of the binder component is a particle shape, the average primary particle diameter of the binder particles is preferably 3 to 7000 μm, more preferably 30 to 3000 μm, and further preferably 100 to 1000 μm. When the binder particles are not spherical, the average primary particle diameter of the binder particles is determined by calculating the projected area of the particles with a transmission electron micrograph, and the diameter of a circle having the same area is defined as the average primary particle diameter. By making the average primary particle diameter of the binder particles within the above range, it is possible to make a net, and it is possible to obtain a substrate for a fiber-reinforced plastic molded body by a wet papermaking method.

  When the shape of the binder component is a fiber shape, the fiber length of the binder fiber is preferably 3 mm or more, more preferably 10 mm or more, further preferably 15 mm or more, and particularly preferably 20 mm or more. preferable. In addition, the fiber length of a binder fiber can also be 50 mm or more. The fiber length of the binder fiber is preferably 150 mm or less, more preferably 100 mm or less, and further preferably 75 mm or less. In addition, in this specification, the fiber length of a binder fiber is a mass average fiber length, and is the average value of the fiber length measured about 100 fibers.

  When the shape of the binder component is a fiber shape, the fiber diameter of the binder fiber is preferably 3 to 25 μm. In addition, in this specification, the fiber diameter of a binder fiber is a number average fiber diameter, and is an average value of the fiber diameter which measured the fiber diameter of 100 fibers.

  The binder component may be contained in an aqueous solution or an emulsion. By applying such an aqueous solution or emulsion to a contact point or the like of a reinforcing fiber by a method such as spraying or impregnation, a base material for a fiber-reinforced plastic molded body containing a binder component can be obtained.

(Other ingredients)
The base material for fiber-reinforced plastic molded bodies is substantially free of thermoplastic fibers. Here, the phrase “substantially free of thermoplastic resin” means that the thermoplastic fiber content relative to the entire substrate for fiber-reinforced plastic molding is 0.1% by mass or less. The thermoplastic fibers include, for example, polycarbonate (PC), polyether ether ketone (PEEK), polyamide imide (PAI), polyphenylene sulfide (PPS), polyether imide (PEI), polyether ketone ketone (PEKK), polyamide. , Polypropylene.

(Manufacturing method of base material for fiber reinforced plastic molding)
The manufacturing process of the base material for fiber-reinforced plastic molded bodies of the present invention includes a process of wet papermaking a slurry in which reinforcing fibers and a binder component are mixed. This wet papermaking step is a step of making paper using an inclined paper machine, and the wire of the inclined paper machine runs so that the jet wire ratio is 0.98 or less. The present invention also relates to a substrate for a fiber-reinforced plastic molded body produced by such a production method.

  The jet wire ratio of the wire of the inclined paper machine may be 0.98 or less, more preferably 0.96 or less, further preferably 0.90 or less, and 0.80 or less. Is particularly preferred.

Here, the jet wire ratio is a ratio of the supply speed of the slurry containing the reinforcing fiber and the binder component and the wire travel speed, and is represented by the slurry supply speed / wire travel speed. When the jet wire ratio is greater than 1, the slurry supply speed is faster than the wire traveling speed, and this case is referred to as “pushing”. When the jet wire ratio is 1 or less, the slurry supply speed is slower than the wire traveling speed, and this case is referred to as “pulling”.
In the present invention, the fiber orientation parameter (fp) in the thickness direction of the base material for fiber reinforced plastic molded body may be within a desired range by making the jet wire ratio within the above range and making paper by “drawing”. it can. Furthermore, the fiber orientation parameter (fp) in the planar direction of the substrate for fiber reinforced plastic molding can be set within a desired range.

  In the method for producing a base material for a fiber-reinforced plastic molded body of the present invention, it is preferable to appropriately adjust the suction force of a plurality of wet suction boxes provided in the inclined wire of the inclined paper machine. Specifically, it is preferable to adjust so that the amount of dewatering of the wet suction box on the downstream side of the inclined wire is increased. Usually, when the suction force of the wet suction box is made uniform, the amount of dewatering on the upstream side of the wire increases and the amount of dewatering on the upstream and downstream sides of the wire tends to decrease. For this reason, in the manufacturing method of the present invention, the upstream suction force is made weaker than the downstream suction force, and the dewatering amount of the wet suction box on the downstream side of the inclined wire is adjusted so as to increase the dewatering amount on the wire. The base material for a fiber-reinforced plastic molded body is uniformly dehydrated. As described above, the fiber orientation parameter (fp) in the thickness direction can be set within a desired range also by performing uniform dehydration.

When paper making a substrate for a fiber reinforced plastic molded article, the viscosity of the slurry dispersion medium at 25 ° C. is preferably 0.8 to 4.0 mPa. The viscosity of the slurry dispersion medium at 25 ° C. is more preferably 1.0 to 3.5 mPa, and further preferably 1.0 to 3.0 mPa. Here, the viscosity of the dispersion medium of the slurry at 25 ° C. is measured by a measuring method defined in JIS Z 8803 “Method for Measuring Viscosity of Liquid”.
In addition, a slurry here means the slurry immediately before a papermaking process, and is a slurry in an inlet. Further, when measuring the viscosity of the slurry dispersion medium, 500 ml of the inlet slurry is collected and measured using a filtrate obtained by filtering the fibers with a 150-mesh metal sieve.

  The viscosity of the slurry dispersion medium can be adjusted, for example, by adding a polyacrylamide-based viscous agent to the inlet. By setting the viscosity of the dispersion medium of the slurry within the above range, the dispersion of the dispersion liquid in the vicinity of the wire can be prevented from being disturbed and a laminar flow can be obtained. Thereby, the fiber orientation parameter (fp) of the thickness direction of the base material for fiber reinforced plastic molded objects can be made into a desired range.

In addition, in the process of manufacturing the base material for fiber-reinforced plastic molded bodies, the binder component can be added after the paper making process. For example, a solution containing a binder component or an emulsion containing a binder component may be internally added, applied or impregnated into a paper-made sheet, and dried by heating. By providing such a process, it is possible to suppress the scattering, fluffing and dropping off of the surface fibers of the substrate for fiber reinforced plastic molding, and to obtain a substrate for fiber reinforced plastic molding having excellent handling properties. it can.
In addition, as described above, by providing the heat drying step, the solution containing the binder component or the emulsion containing the binder component can be transferred to the surface layer region of the substrate for fiber-reinforced plastic molded body. In addition, the binder component can be localized in the form of a water scraping film.

(Molding method of fiber reinforced plastic molding)
The base material for a fiber reinforced plastic molded body of the present invention becomes a fiber reinforced plastic molded body by further containing a resin. The manufacturing process of the fiber reinforced plastic molded body molded from the fiber reinforced plastic molded body base material is a step of impregnating the fiber reinforced plastic molded body base material with a resin to obtain a resin-containing fiber reinforced plastic molded body base material, or A step of laminating a resin to obtain a base material for a resin-containing fiber-reinforced plastic molded article. Furthermore, the manufacturing process of the fiber reinforced plastic molded body includes a step of heating and pressurizing the substrate for resin-containing fiber reinforced plastic molded body. As described above, the fiber-reinforced plastic molded body is molded by adding a resin to the above-described base material for fiber-reinforced plastic molded body and applying at least pressure.

  The base material for a fiber reinforced plastic molded body can be processed into an arbitrary shape according to the target shape and molding method. In the step of obtaining a resin-containing fiber-reinforced plastic molded body substrate, the fiber-reinforced plastic molded body substrate is laminated alone or in a desired thickness. Such a single-layer or multi-layer fiber reinforced plastic molded body substrate is impregnated with resin or laminated with resin.

  As the matrix resin to be impregnated into the fiber reinforced plastic molded base material, a matrix resin mainly composed of a thermosetting resin dissolved in a solvent can be used. The type of thermosetting resin is not particularly limited. For example, unsaturated polyester resin, vinyl ester resin, epoxy resin, phenol (resole type) resin, urea / melamine resin, polyimide resin, and the like, copolymers, and modified products thereof. , And resins obtained by blending at least two of these. Among these, since it is excellent in rigidity and strength, a thermosetting resin mainly composed of an epoxy resin is preferably used. These resins are also preferably used from the viewpoint of the mechanical properties of the molded product. When a thermosetting resin is used, a thermoplastic resin and / or other elastomer or rubber component may be added to the thermosetting resin in order to improve impact resistance and the like.

  As the matrix resin, for example, a thermoplastic resin can be used. In this case, a thermoplastic resin can be dissolved in a solvent, or an emulsion can be impregnated into the fiber-reinforced plastic molded base material of the present invention, followed by heat and pressure molding. As thermoplastic resins, polycarbonate (PC), polyetheretherketone (PEEK), polyamideimide (PAI), polyphenylene sulfide (PPS), polyetherimide (PEI), polyetherketoneketone (PEKK), polyamide, polypropylene, etc. Can be illustrated. Among these, in order to obtain a high-strength fiber-reinforced plastic molded body, it is preferable to use polycarbonate, polyetherimide, or polyamide. The polyamide is preferably nylon, and more preferably nylon 6.

In the step of impregnating a resin for a fiber reinforced plastic molded body to obtain a resin-containing fiber reinforced plastic molded body base material, a prepreg in which a fiber reinforced plastic molded body base material is pre-impregnated with a matrix resin may be prepared. Good. A fiber-reinforced plastic molded body can be formed by pressurizing or heating and pressing such a prepreg. Further, the fiber reinforced plastic molded body can be molded by a method such as a hand layup method or RTM.
Moreover, in the step of obtaining a base material for resin-containing fiber-reinforced plastic molded bodies by laminating a resin, it is preferable to laminate or sandwich a resin film and heat and press. In addition, various conditions, such as the thickness of the resin film in the said process, can be suitably adjusted based on a use, a physical property, thickness, etc. of a fiber reinforced plastic molding.

  In the step of heating and pressurizing the resin-containing fiber-reinforced plastic molded body substrate, the resin-containing fiber-reinforced plastic molded body substrate to which the resin has been added by the above-described method is hot-pressed or pre-heated with an infrared heater or the like. Heat-press molding. As a molding method, a general method for heating and pressing a base material for a fiber-reinforced plastic molded body can be used.

  Among the various press forming methods, the press molding method includes an autoclave method that is often used when forming a molded body member such as a large aircraft, and a die press method in which the process is relatively simple. Preferably mentioned. The autoclave method is preferred from the viewpoint of obtaining a high-quality fiber-reinforced plastic molded body with few voids. On the other hand, from the viewpoint of energy consumption in equipment and molding process, simplification of jigs and auxiliary materials to be used, molding pressure, and flexibility of temperature, metal molds are used for molding. It is preferable to use a mold press method, and these can be selected according to the application.

  For the die pressing method, a heat and cool method or a stamping molding method can be employed. In the heat and cool method, a substrate for a fiber reinforced plastic molded body is placed in a mold in advance, pressurized and heated together with the mold clamping, and then the mold is cooled while the mold is cooled. This is a method for obtaining a molded body by cooling. In the stamping molding method, the base material is previously heated by a heating device such as a far-infrared heater, a heating plate, a high-temperature oven, and dielectric heating, and the thermoplastic resin is melted and softened, and then placed inside the molded body mold. Next, the mold is closed, the mold is clamped, and then the pressure is cooled. Moreover, when the temperature at the time of shaping | molding is comparatively low, such as when obtaining a low density molded object, a hot press method can also be employ | adopted.

  Molds for molding are roughly classified into two types, one is a sealed mold used for casting or injection molding, and the other is an open mold used for press molding or forging. When the base material for a fiber-reinforced plastic molded body of the present invention is used, any mold can be used depending on the application. An open mold is preferable from the viewpoint of eliminating decomposition gas and mixed air from the mold during molding, but in order to suppress excessive resin flow, the number of open parts should be reduced as much as possible during the molding process. It is also preferable to adopt a shape that suppresses outflow from the mold.

  Furthermore, the metal mold | die which has at least 1 type selected from a punching mechanism and a tapping mechanism can be used for a metal mold | die. It is also possible to punch the formed body continuously after hot pressing by means such as using a two-stage press mechanism. In addition, depending on the purpose of use, the molded body can be provided with a pattern for the purpose of reinforcing strength such as ribs and bosses, forming projections and screw holes for processing, and imparting design properties.

  When the fiber reinforced plastic molded body has a multilayer structure, other types of fiber reinforced plastic molded body substrates can be laminated and heat-press molded by hot pressing. It is also possible to bond more complicated shaped members by outsert molding or insert molding at the same time as or after molding the fiber-reinforced plastic molded body.

  When molding a fiber reinforced plastic molded body from a fiber reinforced plastic molded body substrate, when using a thermoplastic resin as a matrix resin, add the resin-containing fiber reinforced plastic molded body substrate at 150 to 600 ° C. It is preferable to press-mold. The heating temperature is preferably a temperature range in which the thermoplastic resin fibers flow and the reinforcing fibers do not melt.

  As a pressure at the time of shape | molding the base material for resin containing fiber reinforced plastic molded objects, 0.5-20 Mpa is preferable. Moreover, from the viewpoint of suppressing the breakage of the reinforcing fibers and improving the strength, it is more preferably 0.5 to 10 MPa, and further preferably 1 to 8 MPa. When using a thermosetting resin, or when using a resin that is mixed and impregnated with a curing agent just before impregnating the resin into a fiber reinforced plastic molded body and cured at room temperature, the molding temperature is appropriately determined according to the resin. Can be set. Moreover, when using the said resin, a fiber reinforced plastics molded object can also be shape | molded only by pressurization, without heating.

(Fiber reinforced plastic molding)
The present invention also relates to a fiber-reinforced plastic molded body molded by the above-described method. The fiber-reinforced plastic molded article of the present invention contains reinforcing fibers, a binder component, and a resin component. The absolute value of the fiber orientation parameter (fp) in the thickness direction in the fiber reinforced plastic molded product is 0.5 to 1.0.

  The fiber orientation parameter (absolute value of fp) in the thickness direction in the fiber reinforced plastic molded body may be 0.5 to 1.0, preferably 0.6 to 1.0, 0.7 to 1 0.0 is more preferable, 0.8 to 1.0 is more preferable, and 0.9 to 1.0 is particularly preferable. By setting the absolute value of the fiber orientation parameter (fp) in the thickness direction within the above range, the orientation of the reinforcing fibers in the thickness direction can be adjusted, and the bending strength of the fiber-reinforced plastic molded product can be improved.

  The absolute value of the fiber orientation parameter (fp) in the plane direction in the fiber-reinforced plastic molded body is preferably 0.18 to 1.0, more preferably 0.25 to 1.0, and It is more preferable that it is 3-1.0, and it is especially preferable that it is 0.6-1.0. That is, in the fiber-reinforced plastic molded article of the present invention, it is preferable that the reinforcing fibers have a uniform orientation in the plane direction in addition to the uniform orientation in the thickness direction. As described above, in the fiber-reinforced plastic molded article, it is preferable that the reinforcing fibers have a constant orientation in the plane direction in addition to the constant orientation in the thickness direction.

  The geometric mean value of the bending strength in the MD direction and the bending strength in the CD direction of the fiber-reinforced plastic molded body of the present invention is preferably 280 MPa or more, more preferably 300 MPa or more, and further preferably 320 MPa or more. It is preferably 350 MPa or more. Further, the bending strength in the MD direction of the fiber-reinforced plastic molded body of the present invention is preferably 310 MPa or more, more preferably 350 MPa or more, further preferably 500 MPa or more, and preferably 600 MPa or more. Particularly preferred.

Furthermore, the strength ratio between the bending strength in the first direction and the bending strength in the second direction orthogonal to the first direction of the fiber-reinforced plastic molded body is preferably 3 or more, and preferably 4 or more. The above is also preferable. In addition, the 1st direction means the orientation direction of the reinforced fiber in a fiber reinforced plastic molding, and the 2nd direction means the direction orthogonal to the orientation direction of a reinforced fiber. In the present invention, when the reinforcing fibers are oriented in the MD direction, the first direction is the MD direction, and the second direction is the CD direction (a direction orthogonal to the flow direction of the papermaking line).
As described above, in the fiber reinforced plastic molded body of the present invention, the strength and the strength in the specific direction of the fiber reinforced plastic molded body are increased because the thickness direction and the plane direction orientation of the reinforced fibers are constant. . For this reason, the fiber-reinforced plastic molded body of the present invention is preferably used for structural parts that require mechanical strength in one direction used in automobiles, aircraft, and the like.

  The thickness of the fiber-reinforced plastic molded body is not particularly limited, but can be 0.1 to 50 mm.

(Applications of fiber-reinforced plastic moldings)
Examples of the application of the fiber reinforced plastic molded body include “OA devices, mobile phones, smartphones, personal digital assistants, tablet PCs, digital video cameras and other portable electronic devices, air conditioners and other home appliances, and housings. Reinforcing materials such as ribs to be affixed, civil engineering such as “posts, panels, reinforcing materials”, building material parts, “various frames, various wheel bearings, various beams, doors, trunk lids, side panels, upper back panels, front bodies , Underbody, various pillars, various frames, various beams, various supports, etc. or body parts and reinforcements thereof, “interior parts such as instrument panels and seat frames”, or “gasoline tanks, various piping, Fuel system such as various valves, exhaust system, or intake system parts "," engine Automobile parts such as water rejection joints, thermostat bases for air conditioners, headlamp supports, pedal housings, etc., aircraft parts such as `` winglets, spoilers '', `` seat components for rail vehicles, outer panel, Reinforcing materials to be attached to the outer panel, ceiling panels, jet parts for air conditioners, etc., “reinforcing materials for molded products made of resin (thermosetting resin, thermoplastic resin), resin and reinforcing fibers” Reinforcing materials for molded products made of, reinforcing materials for plant-derived sheets (craft paper, cardboard, oil-resistant paper, insulating paper, conductive paper, release paper, impregnated paper, glassine paper, cellulose nanofiber sheet, etc.) Is preferably used. Furthermore, since the fiber-reinforced plastic molded article of the present invention is excellent in flame retardancy even when thin, it can be suitably used as a substrate for electrical insulation by using glass fibers having high electrical insulation as the reinforcing fibers.
As described above, the fiber-reinforced plastic molded body of the present invention has high strength and has excellent flame retardancy, so it has high safety. Therefore, the housing for electric and electronic devices, structural parts for automobiles, and aircraft It is preferably used for various parts, civil engineering, building material panels, and other various applications.

The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. In the following, Examples 1, 7, and 8 are read as Reference Examples 1, 7, and 8, respectively.

<Example 1>
<Manufacture of reinforcing fiber slurry>
Carbon fiber with a fiber length of 12 mm (manufactured by Taiwan Plastic Co., Ltd., CS815) was introduced into water so that the slurry concentration was 0.5 mass%, and Emanon (registered trademark) 3199V (manufactured by Kao Corporation) was used as a dispersant. It added so that it might become 1 mass part with respect to 100 mass parts of fibers. In addition, Emanon 3199V was dissolved in water and added in advance so as to obtain an aqueous solution having a concentration of 0.5%. Thereafter, initial dispersion was performed by stirring for 30 seconds using a waste paper disaggregating pulper, and then diluted with water so that the slurry concentration became 0.15% by mass. The resulting slurry was a carbon fiber slurry.

  In a separate container, an aqueous solution in which powdered anionic polymer polyacrylamide thickener (manufactured by MT Aquapolymer Co., Ltd., Sumifloc) was dissolved was prepared. The powdered anionic polymer polyacrylamide type thickener was added so that it might become 0.1 mass% with respect to the total mass of aqueous solution. This aqueous solution was added to the carbon fiber slurry. The addition amount of the aqueous solution was adjusted so that the solid content of the thickener was 60 ppm with respect to the total mass of the aqueous solution. Then, it stirred and disperse | distributed until carbon fiber became monofilament.

  Next, as a binder component, fibrous PVA (manufactured by Kuraray Co., Ltd., VPB105-2) was weighed so as to be 3% by mass with respect to the mass of the fiber-reinforced plastic molded body. This was dispersed in water separated into a separate container so that the slurry concentration was 10% by mass to obtain a binder fiber slurry. In addition, since the binder fiber had good dispersibility, it was sufficiently dispersed without any particular treatment such as stirring. This binder fiber slurry was put into the carbon fiber slurry and diluted with water to obtain a raw material slurry having a concentration of 0.2% by mass.

<Manufacture of substrate for fiber-reinforced plastic molding>
The raw material slurry was continuously supplied to the inclined wire machine, and paper making was performed to prepare a substrate for a fiber-reinforced plastic molded body.
In the paper making process, the raw slurry was fed into the inlet, and the inlet concentration was diluted to 0.03% by mass with circulating white water. At this time, an aqueous solution of a polymer polyacrylamide-based thickener (manufactured by MT Aqua Polymer Co., Ltd., Sumifloc) was appropriately added into the inlet, and the viscosity of the slurry dispersion medium was adjusted to the value shown in Table 1. The viscosity of the slurry dispersion medium was measured using a filtrate obtained by collecting 500 ml of the inlet slurry and filtering the fiber with a 150-mesh metal sieve. The viscosity of the slurry dispersion medium is a viscosity at a liquid temperature of 25 ° C., and was measured by a measurement method defined in JIS Z 8803 “Method for Measuring Viscosity of Liquid”.
Subsequently, the slurry was continuously supplied to the inclined wire machine. At this time, the white water circulation flow rate and the paper making speed were adjusted to adjust the jet wire ratio as shown in Table 1. During paper making, the suction force of the four dewatering boxes provided on the wires of the inclined wire machine was individually adjusted so that the four dehydrated amounts were almost the same. Thus, the base material for fiber reinforced plastic moldings was produced.

<Example 2>
A substrate for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the viscosity of the slurry dispersion medium and the jet wire ratio were as shown in Table 1.

<Example 3>
A substrate for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the viscosity of the slurry dispersion medium and the jet wire ratio were as shown in Table 1.

<Example 4>
A substrate for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the viscosity of the slurry dispersion medium and the jet wire ratio were as shown in Table 1.

<Example 5>
A substrate for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the viscosity of the slurry dispersion medium, the jet wire ratio, and the fiber length of the carbon fiber were as shown in Table 1.

<Example 6>
Substrate for fiber reinforced plastic molding was obtained in the same manner as in Example 5 except that the carbon fiber was changed to glass fiber and the viscosity of the slurry dispersion medium was as shown in Table 1.

<Example 7>
A substrate for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the viscosity of the slurry dispersion medium and the jet wire ratio were as shown in Table 1.

<Example 8>
A substrate for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the viscosity of the slurry dispersion medium and the jet wire ratio were as shown in Table 1.

<Comparative Example 1>
A substrate for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the viscosity of the slurry dispersion medium and the jet wire ratio were as shown in Table 1.

<Comparative example 2>
A substrate for a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the viscosity of the slurry dispersion medium and the jet wire ratio were as shown in Table 1.

<Measurement of fiber orientation parameter (fp value) in thickness direction>
The substrate for fiber-reinforced plastic molded bodies obtained in Examples and Comparative Examples was cut into a width of 5 mm and a length of 10 mm, and an ultraviolet-curable epoxy resin for embedding (Aronix LCA D-800, manufactured by JEOL Ltd.) Was impregnated by dropping with a dropper so as to cover the entire surface of the test piece, and cured by irradiation with ultraviolet rays.
And the specimen for cross-sectional observation of width 0.4mm and length 10mm was cut out from hardened | cured material using the JASCO Corporation make and slice master HS-1. The cutting direction was the BB ′ direction in FIG.
The cross section in the thickness direction of the obtained test piece was magnified 300 times with a microscope manufactured by Keyence Corporation, and the fibers were observed with transmitted light. Here, a continuous measurement area of 1.5 mm ^{2 in} the cross section was observed. Further, observation was performed by focusing on a portion having a depth of 10 μm or more from each of the observation surface and the opposite surface of the test piece. Then, the angle θi (i = 1 to n) with respect to a reference line set by a method described later is measured for all fibers (number of fibers is n) that are present in the measurement region and can be visually recognized in the observation image. did. The orientation angle θi is an angle of 0 ° or more and less than 180 ° by measuring the angle in the clockwise direction with respect to the reference line. And the fiber orientation parameter of the thickness direction was computed from the angle (theta) i of the fiber with respect to the set reference line using the following formula | equation (1).
fp = 2 × Σ (cos ² θ _i / n) −1 Formula (1)

The reference line was determined by the following method. In determining the reference line, first, the temporary reference line p was selected, and the angles of all visible fibers existing in the measurement region were measured. In this case, the angle between the temporary reference line p and each fiber is represented by α (p) _i (i = 1 to n).
The fiber orientation parameter (fp (p)) with the provisional reference line p was calculated using the following formula.
fp (p) = 2 × Σ (cos ² α (p) _i / n) −1
(I = 1, 2, 3,..., N)
Next, the temporary reference line p (p _{+ z} , p _−z (z = 1 to 90)) obtained by rotating the temporary reference line p by ± 1 ° to ± 90 ° is taken, and the temporary reference line p _{+ z} And the angle of the temporary reference line p _-z and n fibers. The angles in this case are represented by α (p _{+ z} ) _i and α (p _−z ) _i (i = 1 to n).
The rotated temporary reference lines (p _{+ z} , p- _z (z = 1 to 90)) and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber were calculated using the following formula.
fp (p ± _z ) = 2 × Σ (cos ² α (p ± _z ) _i / n) −1
(I = 1, 2, 3,..., N)
Thus, the temporary reference line set when the maximum value was obtained among the obtained fp (p) value and fp (p ± _z ) value was used as the reference line.

<Measurement of fiber orientation parameter (fp value) in planar direction>
The substrate for fiber-reinforced plastic molded body obtained in Examples / Comparative Examples was cut out to have a width of 3 cm and a length of 3 cm, this test piece was sandwiched between slide glasses, and one surface of the test piece was placed on an optical microscope. And observed. For the optical microscope, a microscope manufactured by Keyence Corporation was used, and the fibers were observed with reflected light after being magnified 300 times. Here, a continuous measurement area of 2.0 mm ^{2 on} the one surface was observed. Then, the angle θi (i = 1 to m) with respect to a reference line set by a method described later is measured for all fibers (number of fibers is m) that can be visually recognized in the observation image in the measurement region. did. The orientation angle θi is an angle of 0 ° or more and less than 180 ° by measuring the angle in the clockwise direction with respect to the reference line. And the fiber orientation parameter of the thickness direction was computed from the angle (theta) i of the fiber with respect to the set reference line using the following formula | equation (2).
fp = 2 × Σ (cos ² θ _i / m) −1 Formula (2)
And it measured similarly about the opposite surface, calculated | required the average value of one surface and the opposite surface, and made this the fiber orientation parameter (fp) of a plane direction. In addition, the measurement area | region on the opposite surface to the measurement area | region of one surface was made into the area | region which overlaps in planar view. Further, in any observation of one surface and the opposite surface, the observation was performed by focusing on a portion having a depth of 10 μm or more from each of the one surface and the opposite surface.

The reference line was determined by the following method. In determining the reference line, first, the temporary reference line p was selected, and the angles of all the visible fibers m existing in the measurement region were measured. In this case, the angle between the temporary reference line p and each fiber is represented by α (p) _i (i = 1 to m).
The fiber orientation parameter (fp (p)) with the provisional reference line p was calculated using the following formula.
fp (p) = 2 × Σ (cos ² α (p) _i / m) −1
(I = 1, 2, 3,..., M)
Next, the temporary reference line p (p _{+ z} , p _−z (z = 1 to 90)) obtained by rotating the temporary reference line p by ± 1 ° to ± 90 ° is taken, and the temporary reference line p _{+ z} And the angle of the temporary reference line p _-z and m fibers were calculated. The angles in this case are represented by α (p _{+ z} ) _i and α (p _−z ) _i (i = 1 to m).
The rotated temporary reference lines (p _{+ z} , p- _z (z = 1 to 90)) and the fiber orientation parameter (fp (p ± _z )) of the reinforcing fiber were calculated using the following formula.
fp (p ± _z ) = 2 × Σ (cos ² α (p ± _z ) _i / m) −1
(I = 1, 2, 3,..., M)
Thus, the temporary reference line set when the maximum value was obtained among the obtained fp (p) value and fp (p ± _z ) value was used as the reference line.

<Measurement of bending strength>
The substrate for fiber-reinforced plastic molded body for measuring bending strength obtained in Examples and Comparative Examples was cut out to have a width of 10 cm and a length of 10 cm, and laminated in the same paper making direction so that the total weight was 10 g. did. To this laminate, an epoxy resin (GM-6800 manufactured by Benny Co., Ltd.) kneaded with a curing agent added is dropped with a 15 g dropper, inserted into a hot press at a temperature of 60 ° C., and molded at a pressure of 8 MPa for 2 hours. As a result, a fiber-reinforced plastic molding was obtained.
According to JIS K7074 “Bending test method for carbon fiber reinforced plastic”, the obtained fiber reinforced plastic molded product was subjected to a fiber orientation direction (machine direction, hereinafter referred to as MD) and a fiber orientation direction (cross direction, hereinafter referred to as MD). CD), and the strength and strength ratio in the MD direction and the CD direction were measured.
The geometric mean value of bending strength was calculated by the following formula.
The geometric mean value of bending strength = √ (FMD × FCD)
Here, FMD represents the bending strength in the MD direction, and FCD represents the bending strength in the CD direction.

  From Table 1, it can be seen that when a fiber reinforced plastic molded body is molded using the fiber reinforced plastic molded body obtained in the examples, a fiber reinforced plastic molded body having excellent bending strength can be obtained. In particular, the fiber reinforced plastic molded body molded from the fiber reinforced plastic molded body substrate obtained in the examples has excellent bending strength in the MD direction.

DESCRIPTION OF SYMBOLS 10 Base material for fiber-reinforced plastic molded body 20 Reinforcing fiber 30 Binder component 40 Embedding epoxy resin 50 Cross section observation test piece P Reference line P ′ A line parallel to the reference line (auxiliary line)
Q Line representing the angle of the reinforcing fiber relative to the reference line R Line representing the angle of the reinforcing fiber relative to the reference line

Claims (9)

A base material for a fiber reinforced plastic molded article containing a reinforcing fiber and a binder component,
The fiber-reinforced plastic molded body group thickness direction of the fiber orientation parameters in material (fp) is Ri der 0.5-1.0,
A fiber-reinforced plastic molded article base material, wherein a fiber orientation parameter (fp) in a plane direction of the fiber-reinforced plastic molded article base material is 0.3 to 1.0 .   The substrate for fiber-reinforced plastic molded bodies according to claim 1, wherein the reinforcing fibers are carbon fibers. The base material for fiber-reinforced plastic molded bodies according to claim 1 or 2 , wherein the content of the binder component is 0.1 to 10% by mass with respect to the total mass of the base material for fiber-reinforced plastic molded bodies. The fiber length of the said reinforced fiber is 10 mm or more, The base material for fiber reinforced plastic moldings of any one of Claims 1-3 . Including a step of wet papermaking the slurry in which the reinforcing fiber and the binder component are mixed,
The wire of the inclined paper machine is a method for producing a substrate for a fiber-reinforced plastic molded body, characterized in that the jet wire ratio travels so as to be 0.98 or less ,
The fiber orientation parameter (fp) in the thickness direction in the substrate for fiber reinforced plastic molded body is 0.5 to 1.0,
The manufacturing method of the base material for fiber reinforced plastic moldings whose fiber orientation parameter (fp) of the plane direction in the said base material for fiber reinforced plastics moldings is 0.3-1.0 . 6. The method for producing a substrate for a fiber-reinforced plastic molded body according to claim 5 , wherein the wire of the inclined type paper machine travels so that a jet wire ratio is 0.90 or less. The method for producing a substrate for fiber-reinforced plastic molded body according to claim 5 or 6 , wherein the dispersion medium of the slurry has a viscosity at 25 ° C of 0.8 to 4.0 mPa. A method for producing a fiber-reinforced plastic molded body using the substrate for fiber-reinforced plastic molded body according to any one of claims 1 to 4 ,
A step of impregnating a resin for the fiber-reinforced plastic molded body to obtain a resin-containing fiber-reinforced plastic molded body substrate, or a step of obtaining a resin-containing fiber-reinforced plastic molded body substrate by laminating resins;
Pressurizing the base material for a resin-containing fiber-reinforced plastic molded body, and a method for producing a fiber-reinforced plastic molded body. A fiber-reinforced plastic molded article produced by the production method according to claim 8 .

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