JP2019178450A - Method for manufacturing fiber base material and method for manufacturing molding - Google Patents

Abstract

To provide a method for manufacturing a fiber base material for a fiber-reinforced resin molding having a three-dimensional shape.SOLUTION: A method for manufacturing a fiber base material having a bent part (A) includes at least the following steps (I)-(IV): (I) a cutting step of cutting reinforcement fibers discontinuously; (II) an accumulation step of accumulating the reinforcement fibers onto a net-like support body having a bent part (C) having the same shape with that of the bent part (A); (III) a fixation step of fixing the reinforcement fibers to each other with the use of binder; and (IV) a demolding step of removing the fiber base material in which the bent part (A) is formed along the bent part (C) from the support body.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a fiber substrate and a method for producing a molded article.

  In recent years, with respect to industrial products such as automobiles, aircraft, and sports products, market demand for light weight has been increasing year by year. In order to meet such requirements, molded products using fiber reinforced resins that are lightweight and have excellent mechanical properties are widely used in various industrial applications. Among them, fiber reinforced resin molded products using a fiber base material in which reinforcing fibers such as carbon fibers and glass fibers are uniformly dispersed have two-dimensional isotropic properties, and are expected to be used in various structural materials. Therefore, a method for producing a fiber base material has been widely studied.

  In Patent Document 1, as a reinforcing fiber of a fiber-reinforced thermoplastic resin molded body, it is a monofilament-like carbon fiber having a mass average fiber length of 0.5 to 10 mm, and an orientation parameter of −0.25 to It is described that when a carbon fiber of 0.25 is used, a molded article having excellent mechanical properties and isotropic mechanical properties can be obtained. This fiber-reinforced thermoplastic resin molded article is obtained by (I) a step of heating and melting a thermoplastic resin contained in a molding material, (II) a step of placing the molding material in a mold, and (III) adding a molding material in the mold. And (IV) a step of solidifying the molding material in the mold, and (V) a step of opening the mold and demolding the fiber reinforced thermoplastic resin molded body.

  Patent Document 2 describes a fiber base material obtained by blending thermoplastic resin fibers and reinforcing fibers, and a method for producing the same. It is described that a fiber-reinforced thermoplastic resin molded body can be obtained efficiently by heating and pressurizing the resin of the obtained fiber base material by press molding.

  Patent Documents 3 and 4 describe a manufacturing method for obtaining a three-dimensional shape by making a fiber into a three-dimensional shape. By molding into a three-dimensional shape, there is no need to shape the flat fiber substrate into a three-dimensional shape by means such as press molding in order to obtain a three-dimensional shape molded product, and a high-quality molded product can be obtained. It states that it can be done.

Japanese Patent No. 5309563 Japanese Patent No. 5251342 Japanese Patent No. 5949895 Japanese Patent No. 6164485 Japanese Patent No. 2541064

  Although the fiber base material in patent document 1, patent document 2, and patent document 3 has the difference in the presence or absence of a matrix resin fiber, all are flat plate shape. When forming into three-dimensional shapes such as drawing, deep drawing, and overhanging parts found in each structural material, if such a fiber base material is used, the binding between the reinforcing fibers is strong, so that it follows the mold when pressed Otherwise, quality defects such as tearing of the base material and blurring may occur.

  The fiber base material in patent document 4 and patent document 5 has weak binding between fibers, and when the fiber base material is removed from the support, the fiber base material is easily broken.

  Then, the subject of this invention is made | formed in view of the said subject, Comprising: The objective is to provide the manufacturing method of the fiber base material for the fiber reinforced resin molded product which has a three-dimensional shape.

A method for producing a fiber base material having a bent portion (A),
The manufacturing method of a fiber base material including the process of at least following (I)-(IV).
(I) Cutting step for cutting the reinforcing fibers in a discontinuous manner (II) Deposition step (III) for depositing the reinforcing fibers on a net-like support having a bent surface (C) having the same shape as the bent portion (A). Fixing step of fixing the reinforcing fibers to each other with a binder (IV) Demolding step of removing the fiber substrate on which the bent portion (A) is formed along the bent surface (C) from the support.

  According to the method for producing a fiber base material according to the present invention, it is possible to provide a fiber base material that forms a fiber-reinforced resin molded product having excellent appearance quality such as wrinkles.

It is a schematic diagram which shows an example of the fiber base material which concerns on this invention. It is a schematic diagram which shows an example of the cross section (S) of the fiber base material which concerns on this invention. It is a schematic diagram which shows an example of the dispersion state of the reinforced fiber in the molded article which concerns on this invention. It is a schematic diagram which shows an example of the support body which concerns on this invention. It is a schematic diagram which shows an example of the metal mold | die which concerns on this invention.

  Hereinafter, the fiber base material according to the present invention will be described.

The fiber base material 1 which concerns on this invention has a bending part (A). In view of handling property after fiber base manufacture and simplicity of trimming, it is preferable that the fiber base 1 further has a flat portion (B).
<Curved part>
The bent portion (A) will be further described with reference to the drawings. FIG. 1 is a schematic view showing an example of a fiber base material according to the present invention, and a cross section (S) is a cross-sectional view of one of the fiber base materials.

  The shape of the bent portion (A) according to the present invention is not particularly limited as long as the bent portion (A) is bent. However, the bent portion (A) does not have only a flat portion like a flat plate, and has an opening in the bent portion (A). It may be closed or closed. Specifically, it has only a flat plate shape, such as a convex shape such as a conical shape, a hemispherical shape, a polygonal pyramid, a truncated cone shape, a hemispherical shape, a polygonal frustum shape, and / or an uneven pattern shape such as an embossed shape or a wavy shape The shape which is not formed is illustrated. The flat plate shape includes a cubic shape and a rectangular shape. It is desirable that the bent portion (A) which is not flat plate shape is included in the molded product because the mechanical characteristics in the out-of-plane direction of the molded product are improved. Further, since the bent portion (A) is formed in advance on the fiber base material, the fiber base material is formed into a molded product shape when manufacturing a fiber reinforced resin molded product having the fiber base material 1 and the matrix resin (a). Therefore, it is possible to obtain a high-quality fiber-reinforced resin molded product by avoiding molding defects such as wrinkles and tears that occur when molding a conventional flat plate-shaped substrate.

  In the fiber base material according to the present invention, Z> 3T, where Z is the height of the bent portion (A) in the cross section (S), and T is the thickness of the fiber base material. From the viewpoint of having a more complicated three-dimensional shape, Z> 5T is preferable, Z> 8T is more preferable, and Z> 10T is more preferable. The height Z and the thickness T will be further described with reference to FIG. It is a schematic diagram which shows an example of the cross section (S) of the fiber base material which concerns on this invention, and 2 types of fiber base materials are drawn by Fig.2 (a) and FIG.2 (b). In FIG. 2A, the height Z indicates the height from the bottom surface of the plane portion (B) to the apex of the bent portion (A), and the thickness T indicates the thickness of the fiber base material. In FIG.2 (b), the height Z has shown the height from the lowest point of a bending part (A) to a bending part (A), and thickness T has shown the thickness of the fiber base material 1. FIG. . As described above, the height Z indicates the height of a rectangle having a minimum area that the cross section of the fiber base 1 in the cross section (S) circumscribes, and the thickness T indicates the thickness of the fiber base 1. When Z and T are in the above ranges, a molded product obtained by impregnating the fiber base material 1 with the matrix resin (a) is preferable because it exhibits excellent mechanical properties in the out-of-plane direction.

Although it does not restrict | limit especially as a measuring method, The measurement by a cross-sectional photograph is illustrated. A cross-section (S) having a bent portion is photographed in the fiber base material, a rectangle having a minimum area circumscribing the bent portion (A) of the obtained image is drawn, and the height is defined as Z. Moreover, the thickness of arbitrary 10 places of the fiber base material can be measured from the obtained image, and the arithmetic average value of the measurement results of the 10 places can be set as the thickness T.
<(I) Cutting step>
The manufacturing method of the fiber base material 1 which concerns on this invention includes the cutting process which cuts the reinforced fiber 4 discontinuously.

  The types of reinforcing fibers 4 include metal fibers such as aluminum, brass and stainless steel, PAN-based, rayon-based, lignin-based, pitch-based carbon fibers, graphite fibers, insulating fibers such as glass, aramid, PBO, polyphenylene sulfide, Examples thereof include organic fibers such as polyester, acrylic, nylon, and polyethylene, and inorganic fibers such as silicon carbide and silicon nitride. Moreover, the surface treatment may be given to these fibers. Examples of the surface treatment include a treatment with a coupling agent, a treatment with a sizing agent, a treatment with a bundling agent, and an adhesion treatment of an additive in addition to a treatment for depositing a metal as a conductor. Moreover, these fibers may be used individually by 1 type, and may use 2 or more types together. Among these, PAN-based, pitch-based, and rayon-based carbon fibers that are excellent in specific strength and specific rigidity are preferably used from the viewpoint of weight reduction effect. From the viewpoint of improving thermal conductivity so that heat is not trapped in the molded product during processing, PAN-based, pitch-based, rayon-based, etc. carbon fibers or metal fibers are preferred. Moreover, from a viewpoint of improving the economical efficiency of the fiber base material 1 to be obtained, glass fibers are preferably used, and it is particularly preferable to use carbon fibers and glass fibers in combination from the balance between mechanical properties and economic efficiency. Furthermore, aramid fibers are preferably used from the viewpoint of enhancing the impact absorbability and shapeability of the obtained fiber substrate 1, and in particular, carbon fibers and aramid fibers are used in combination from the balance between mechanical properties and impact absorbability. Is preferred. Further, from the viewpoint of increasing the conductivity of the obtained fiber base material 1, reinforcing fibers coated with a metal such as nickel, copper, ytterbium, etc. can also be used. Among these, PAN-based carbon fibers having excellent mechanical properties such as strength and elastic modulus can be used more preferably.

  The reinforcing fiber 4 according to the present invention is cut discontinuously. Since the reinforcing fibers 4 are discontinuous, the reinforcing fibers 4 are discontinuous because the matrix resin (a) can be easily impregnated or the amount thereof can be easily adjusted in the production of a molded product to be described later. .

  The mass average fiber length of the reinforcing fibers 4 in the fiber substrate 1 is preferably in the range of 1 mm to 15 mm. Thereby, the reinforcement efficiency of the reinforced fiber 4 can be improved, and the mechanical characteristic excellent in the fiber base material 1 is given. In addition, by setting the mass average fiber length of the reinforcing fibers 4 within the above range, not only the mechanical characteristics are improved, but also it is easy to deposit on the support 3 by a dry method or a wet method. From the viewpoint of easy deposition, the mass average fiber length is more preferably 1 mm or more and 10 mm or less. The mass average fiber length is obtained by removing resin components of the fiber base material 1 by a method such as burning or elution, and randomly selecting 400 from the remaining reinforcing fibers 4 and measuring the length to a unit of 10 μm. It can be calculated as the average length.

  The reinforcing fiber preferably has a surface oxygen concentration ratio O / C measured by X-ray photoelectron spectroscopy of 0.05 to 0.50, more preferably 0.06 to 0.3, and 0 Even more preferable is a value of 0.07 to 0.2. By ensuring that the surface oxygen concentration ratio is 0.05 or more, the amount of polar functional groups on the surface of the reinforcing fiber is ensured and the affinity with the thermoplastic resin composition is increased, so that stronger adhesion can be obtained. The mechanical properties of the molded product are improved. Moreover, when the surface oxygen concentration ratio is 0.5 or less, it is possible to reduce a decrease in strength of the reinforcing fiber itself due to surface oxidation.

The surface oxygen concentration ratio means the ratio of the number of oxygen (O) and carbon (C) atoms on the fiber surface. The procedure for obtaining the surface oxygen concentration ratio by X-ray photoelectron spectroscopy will be described below with an example. First, the reinforcing fibers from which the sizing agent adhering to the reinforcing fiber surface with a solvent is removed are cut into 20 mm, spread and arranged on a copper sample support base, and then A1Kα1,2 is used as an X-ray source. The chamber is maintained at 1 × 10 ⁸ Torr. The kinetic energy value (KE) of the main peak of C _1s is set to 1202 cV as a peak correction value associated with charging during measurement. C _1s peak area E. Is obtained by drawing a straight base line in the range of 1191 to 1205 eV. O _1s peak area E. Is obtained by drawing a straight base line in the range of 947 to 959 eV.

The surface oxygen concentration is calculated as an atomic ratio by using a sensitivity correction value unique to the apparatus from the ratio between the O _1s peak area and the C _1s peak area. As the X-ray photoelectron spectroscopy apparatus, for example, model ES-200 manufactured by Kokusai Electric Co., Ltd. can be used, and the sensitivity correction value can be calculated as 1.74.

  The means for controlling the surface oxygen concentration O / C of the reinforcing fiber to 0.05 to 0.5 is not particularly limited, but examples include techniques such as electric field oxidation treatment, chemical solution oxidation treatment, and gas phase oxidation treatment. Is done. Of these, electric field oxidation treatment is preferred because it is easy to handle.

  As the electrolytic solution used for the electric field oxidation treatment, aqueous solutions of the following compounds are preferably used. Inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, inorganic hydroxides such as sodium hydroxide, potassium hydroxide and barium hydroxide, inorganic metal salts such as ammonia, sodium carbonate, sodium hydrogen carbonate, sodium acetate, sodium benzoate, etc. Organic salts, and in addition to these sodium salts, potassium salts, barium salts and other metal salts, ammonium salts, and other organic compounds such as hydrazine. Among these, an inorganic acid is preferable as the electrolytic solution, and sulfuric acid and nitric acid are particularly preferably used. The degree of the electric field treatment can control O / C on the surface of the reinforcing fiber by setting the amount of electricity flowing in the electric field treatment.

Moreover, there is no restriction | limiting in particular in the number of the single fiber which comprises the reinforced fiber 4, From a viewpoint of productivity, 24,000 or more are preferable and 48,000 or more are more preferable. Although there is no restriction | limiting in particular about the upper limit of the number of single fibers, In consideration of balance with productivity and handleability, if there are about 300,000, productivity and handleability can be kept favorable.
<(II) Deposition step>
The fiber base material 1 according to the present invention is obtained by depositing the reinforcing fibers 4 on a net-like support 3 having at least one bent surface (C) having the same shape as the bent portion (A).

  Since the support 3 is a net-like structure, not only can the reinforcing fiber 4 be fixed to the support 6 by suction from the surface of the support 3 opposite to the surface on which the reinforcing fibers 4 are deposited. The additive adhering to can be removed.

  Furthermore, as shown in FIG. 4, it is preferable that the reinforcing fibers 4 are continuously deposited on the support 3, and the support 3 has a bent surface (C) having the same shape as the bent portion (A). The shape of the bent portion (A) of the molded product is determined along the bent surface (C). The support 3 may be long so that the reinforcing fibers 4 are continuously deposited, or may be short so that the reinforcing fibers 4 are deposited in batch units, but the support 3 is long. And having the shape of the bent surface (C) in at least one place, the support 3 is continuously conveyed using a conveying device such as a conveyor, and the reinforcing fibers 4 are supplied thereto. Since the fiber base material 1 can be continuously manufactured, it is preferable from the viewpoint of productivity.

  Further, in order to carry out deposition on the support in an unbiased manner, the normal vector to the support surface on the side where fibers are deposited at any point of the support is directed upward from the horizontal direction when this vector is vertically upward. It is preferable. Such a state is preferable because the reinforcing fibers 4 can be deposited on the support without interruption.

  To the extent that the object of the invention is not impaired, fibers containing a binder or / and matrix resin (a) described later, impact resistance improvers such as elastomers or rubber components, and other fillers and additives are used as reinforcing fibers 4. And may be deposited together. Examples of fillers and additives include inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, and coloring inhibitors. And a heat stabilizer, a release agent, an antistatic agent, a plasticizer, a lubricant, a colorant, a pigment, a dye, a foaming agent, an antifoaming agent, or a coupling agent. By depositing together, not only the binder and / or matrix resin (a) can be easily impregnated into the reinforcing fibers 4 in the subsequent manufacturing process of the molded product, but also defects such as voids in the molded product can be prevented. Since it can reduce, it is preferable.

  The deposition of the reinforcing fibers 4 can be performed by either a dry method or a wet method. The dry method is a method of depositing the reinforcing fibers 4 in the air, and the wet method is a method of depositing the reinforcing fibers 4 in the water.

  In the case of the dry method, the fiber base material can be obtained by depositing the reinforcing fibers 4 in the gas phase. The reinforcing fibers 4 are deposited in the gas phase by opening the reinforcing fibers 4 in a non-contact manner, depositing the opened reinforcing fibers 4 (non-contact method), or applying an air flow to the reinforcing fibers 4. 3 of a method of spreading and spreading the opened reinforcing fibers 4 (method using an air flow), and a method of opening the reinforcing fibers 4 in a contact manner and depositing the opened reinforcing fibers 4 (contact method). There are types.

  The non-contact method is a method in which the reinforcing fibers 4 are opened without bringing a solid or an opening device into contact therewith. For example, a method of spraying a gas such as air or an inert gas onto the reinforcing fiber 4, preferably a method of pressurizing and spraying air advantageous in terms of cost.

  In the method using an air flow, the conditions for applying the air flow to the reinforcing fibers 4 are not particularly limited. For example, pressurized air (normally 0.1 MPa or more and 10 MPa or less, preferably an air flow in which a pressure of 0.5 MPa or more and 5 MPa or less is applied) is applied until the reinforcing fibers 4 are opened. In the method using an air flow, an apparatus that can be used is not particularly limited, but a container that includes an air tube and is capable of air suction and can contain the reinforcing fibers 4 can be exemplified. By using such a container, the opening and deposition of the reinforcing fibers 4 can be performed in one container.

  The contact method is a method in which the reinforcing fiber 4 is physically contacted with a solid or an opening device to open the fiber. Examples of the contact method include carding, needle punching, and roller opening, among which carding and needle punching are preferable, and carding is more preferable. The conditions for carrying out the contact method are not particularly limited, and conditions for opening the reinforcing fibers 4 can be determined as appropriate.

  In the case of the wet method, the fiber base material can be obtained by depositing the reinforcing fibers 4 in water.

  As water (dispersion liquid) for depositing the reinforcing fibers 4, water such as distilled water and purified water can be used in addition to normal tap water. A surfactant may be mixed in the water as necessary. Surfactants are classified into a cation type, an anion type, a nonionic type, and an amphoteric type. Of these, nonionic surfactants are preferably used, and polyoxyethylene lauryl ether is more preferably used. . The concentration of the surfactant when mixing the surfactant with water is usually 0.0001% by mass or more and 0.1% by mass or less, preferably 0.0005% by mass or more and 0.05% by mass or less. By being in this range, it becomes easy to disperse the reinforcing fibers 4 in a substantially monofilament random form, which will be described later, which is a preferred embodiment of the fiber substrate 1.

  The addition amount of the reinforcing fibers 4 with respect to water (dispersion) can be adjusted in the range of usually 0.1 g or more and 10 g or less, preferably 0.3 g or more and 5 g or less as the amount per 1 l of water (dispersion). By setting it as the said range, the slurry in which the reinforced fiber 4 was efficiently opened to water (dispersion liquid) can be obtained in a short time. When the reinforcing fiber 4 is dispersed in water (dispersion), stirring is performed as necessary.

  Slurry refers to a suspension in which solid components are dispersed. In the present invention, a slurry is preferably an aqueous slurry. The reinforcing fiber 4 can be deposited on the support 3 by sucking water from the slurry. The deposition by the slurry can be performed following the so-called papermaking method. The deposition by the wet method is not limited to the papermaking method, but, as an example, it can be performed by pouring slurry into a tank having a net-like support at the bottom and sucking water from the bottom, and sucking the water. .

  The solid content concentration (mass content of reinforcing fibers in the slurry) in the slurry is preferably 0.01% by mass or more and 1% by mass or less, and preferably 0.03% by mass or more and 0.5% by mass or less. More preferred. By being in the above range, deposition can be performed uniformly and efficiently on a support having a bent portion.

The basis weight of the fiber base material is preferably 10 g / m ² or more and 500 g / m ² or less, more preferably 50 g / m ² or more and 300 g / m ² or less. Any of the above upper limits may be set as the upper limit, and any of the above lower limits may be set as the lower limit. If it is less than 10 g / m ^2, it may cause problems in handling properties such as tearing of the substrate. If it exceeds 500 g / m ² , it takes a long time to dry the substrate in the wet method, or In some cases, the material may become thick, and handling may be difficult in subsequent processes.

  Furthermore, it is desirable that the reinforcing fibers 4 are discontinuous, have a substantially monofilament shape, and are randomly dispersed in the fiber substrate 1. By making the reinforcing fiber 4 into such an embodiment, isotropic and homogeneity can be imparted to the molded product obtained from the molded substrate 1.

  Here, “substantially monofilament” means that the reinforcing fiber single yarn is present in less than 500 fineness strands. More desirably, it is dispersed as a monofilament, that is, as a single yarn.

  Moreover, about monofilament shape or dispersed in a monofilament shape, the proportion of single fibers whose two-dimensional orientation angle is 1 ° or more with respect to the reinforcing fibers 4 arbitrarily selected in the fiber substrate 1 ( Hereinafter, it is also referred to as a fiber dispersion ratio) of 80% or more. In other words, in the fiber base 1, two or more single fibers are in contact with each other and a bundle in parallel is less than 20%. Therefore, it is particularly preferable that the mass fraction of the fiber bundle having at least 100 filaments in the reinforcing fiber 4 corresponds to 100%.

  Further, it is particularly desirable that the reinforcing fibers 4 are randomly dispersed. The fact that the reinforcing fibers 4 are randomly dispersed means that the arithmetic average value of the two-dimensional orientation angle of the arbitrarily selected reinforcing fibers 4 in the fiber substrate 1 is in the range of 30 ° or more and 60 ° or less. . Such a two-dimensional orientation angle is an angle formed by a single fiber of the reinforcing fiber 4 and a single fiber intersecting with the single fiber, and among the angles formed by the intersecting single fibers, 0 ° or more, It is defined as the angle on the acute angle side within the range of 90 ° or less.

  This two-dimensional orientation angle will be further described with reference to the drawings. 3A and 3B are schematic views showing an example of a dispersion state of the reinforcing fibers 4 in the fiber base material 1 according to the present invention. FIG. 3A is a view as seen from the plane direction, and FIG. is there. 3A and 3B, when the single fiber 4a is used as a reference, the single fiber 4a intersects with the other single fibers 4b to 4f. Here, the intersection means a state in which a single fiber as a reference is observed crossing another single fiber in a two-dimensional plane to be observed, and the single fiber 4a and the single fibers 4b to 4f are not necessarily in contact with each other. There is no need to do so, and there is no exception to the state observed when they are projected. That is, when the single fiber 4a serving as a reference is viewed, all of the single fibers 4b to 4f are objects of evaluation of the two-dimensional orientation angle, and in FIG. Of the two angles to be formed, the angle α is an acute angle within a range of 0 ° to 90 °.

  Although there is no restriction | limiting in particular as a method of measuring a two-dimensional orientation angle, For example, the method of observing the orientation of the reinforced fiber 4 from the surface of a component can be illustrated. The average value of the two-dimensional orientation angle is measured by the following procedure. That is, the average value of the two-dimensional orientation angles with all the single fibers (single fibers 4b to 4f in FIG. 3) intersecting the randomly selected single fibers (single fibers 4a in FIG. 3) is measured. . For example, when there are many other single fibers that cross a certain single fiber, an arithmetic average value obtained by randomly selecting and measuring 20 other single fibers that intersect may be substituted. This measurement is repeated a total of 5 times with another single fiber as a reference, and the arithmetic average value is calculated as the arithmetic average value of the two-dimensional orientation angle.

Since the reinforcing fibers 4 are dispersed in a substantially monofilament shape and randomly, the performance provided by the reinforcing fibers 4 dispersed in the above-described substantially monofilament shape can be maximized. Further, the fiber base material 1 can impart isotropy to the mechanical properties. From such a viewpoint, the fiber dispersion rate of the reinforcing fibers 4 is desirably 90% or more, and more desirably as it approaches 100%. The arithmetic average value of the two-dimensional orientation angle of the reinforcing fibers 4 is desirably in the range of 40 ° or more and 50 ° or less, and is desirably closer to the ideal angle of 45 °. As a preferable range of the two-dimensional orientation angle, any of the above upper limits may be set as the upper limit, and any of the above lower limits may be set as the lower limit. Examples of the method for making the reinforcing fiber 4 into such an embodiment include the paper making method using the above slurry.
<(III) Fixing Step>
The fiber base material 1 according to the present invention includes a fixing step of fixing the above-described reinforcing fibers 4 to each other with a binder.

  The type of the binder is not particularly limited, and examples thereof include a melt, an aqueous solution, an emulsion, or a suspension of a resin that is a thermosetting resin and / or a thermoplastic resin. By applying the binder to the fiber base material, the reinforcing fibers 4 are fixed to each other and can be removed from the support 3.

  Although it does not restrict | limit especially as resin, Resin of the same kind as the matrix resin (a) mentioned later, or an acrylic polymer, a vinyl polymer, polyurethane, polyamide, and polyester is illustrated. In the present invention, one or two or more selected from these examples are preferably used. By using these resins, it is possible to obtain the fiber substrate 1 having excellent strength. The resin preferably has one or more reactive functional groups selected from an amino group, an epoxy group, a carboxyl group, an oxazoline group, a carboxylate group and an acid anhydride group, and has two or more types. You may do it. Among these, a resin having an amino group and / or an oxazoline group is more preferable.

  The resin melt described above is a state in which a thermosetting resin and / or a thermoplastic resin is heated to its melting temperature Ta. When the binder contains a thermosetting resin, the melting temperature Ta is set to the lowest viscosity observation temperature ± 40 ° C. Since the thermosetting resin is in a state having fluidity before being thermally cured by heating, the fiber base material 1 is impregnated by controlling the temperature near the observation temperature of the minimum viscosity at which the fluidity becomes maximum. Will improve.

  The observation temperature of the minimum viscosity of the thermosetting resin is the heat when the temperature is raised from 40 ° C. to 250 ° C. at a rate of 1.5 ° C./min using a rheometer (rotary dynamic viscoelasticity measuring device). It can be evaluated by observing the observation temperature of the minimum viscosity of the curable resin.

  When the binder contains a thermoplastic resin, the melting temperature Ta is set to be equal to or higher than the melting point (Tm) of the thermoplastic resin. By setting it as this temperature, a thermoplastic resin shows fluidity | liquidity and comes to show the outstanding impregnation property to the fiber base material 1. FIG.

  The melting point (Tm) of the thermoplastic resin can be determined by differential scanning calorimetry (DSC). The peak top of the melting peak in the calorie curve obtained under the temperature rising condition at a temperature rising rate of 10 ° C./min is treated as Tm.

  The above-mentioned resin aqueous solution means a solution in a state almost completely dissolved in water, and a solution in which two liquids that are not completely dissolved in a resin emulsion form fine particles in the liquid. (Emulsion) means suspension and a solution (suspension) suspended in water. The component particle sizes in the liquid are in the order of aqueous solution <emulsion <suspension <melt.

  The binder is preferably applied to the fiber substrate 1 in the form of an aqueous solution, emulsion or suspension. The application method is not particularly limited, and examples thereof include a method in which the binder is dropped onto the fiber substrate, a spraying method, and a method in which the fiber substrate 1 is immersed in a tank filled with the binder. After the application, it is preferable to remove the excess binder by, for example, sucking or absorbing the absorbent material such as absorbent paper from under the support 3 before the drying step.

  The binding amount of the binder in the fixing step is preferably 0.5 to 40% by mass in terms of the amount of the binder with respect to the fiber substrate 1 from the viewpoint of handleability and workability in the cutting step described later. 1 to 20% by mass, more preferably 2 to 10% by mass, and a preferable range of the amount of the binder may be any of the above upper limits, Any lower limit may be used as the lower limit.

  Moreover, it is preferable that the moisture content of the fiber base material 1 in the fixing step is adjusted to 10% by mass or less, preferably 5% by mass or less in advance before applying the binder. Thereby, resin can fully be bound to fiber base material 1, and fiber base material 1 excellent in intensity can be obtained. Furthermore, after giving a binder to the fiber base material 1, it is preferable to heat to 100 ° C. or higher so that the moisture content of the fiber base material 1 is 5% by mass or less. When the moisture content of the fiber base material 1 exceeds 5% by mass after the binder is applied, it becomes water vapor when combined with the matrix resin (a) described later, which causes void formation. In addition, it is necessary to provide an additional drying step, resulting in poor productivity. As the heating temperature, the temperature at which the fiber substrate to which the binder has been applied can be appropriately determined, and is preferably 120 to 300 ° C, more preferably 150 to 250 ° C.

Subsequently, the reinforcing fibers 4 are fixed to each other with the applied binder. Regarding the method for binding the reinforcing fibers, press heating, vacuum heating, and oven heating are preferable from the viewpoint that heat can be efficiently applied. Among these, press heating is preferably used from the viewpoint of applying pressure to more firmly adhere. The conditions for the press heating are not particularly limited, but when performed by a pressure molding machine such as a hydraulic press, the surface pressure is preferably 0.01 MPa or more and 10 MPa or less, and 0.05 MPa or more and 5 MPa or less. In particular, as a preferable range of the surface pressure, any value of the above-described upper limit may be set as the upper limit, and any value of the above-described lower limit may be set as the lower limit. Moreover, it is preferable to fix in the state in which the binder in the fiber base material 1 is melted. In order to obtain a molten state, the fiber base material 1 is preferably heated. Although the heating temperature depends on the type of resin, it is preferably 50 ° C. or higher and 400 ° C. or lower, more preferably 100 ° C. or higher and 300 ° C. or lower, and the preferable range of the heating temperature is the above-described upper limit. Any of the above values may be used as the upper limit, and any of the above lower limits may be used as the lower limit. <(IV) Demolding Step>
The manufacturing method of the shaping | molding base material which concerns on this invention includes the demolding process (IV) which removes the fiber base material 1 fixed on the support body 3. FIG.

  Following the step (III), the fiber substrate 1 is cooled. At this time, from the viewpoint of handleability, it is preferable to cool to a melting temperature Ta-20 ° C. or lower.

The cooled fiber substrate 1 is removed from the support 3. There is no particular limitation on the method for removing the mold, but the mold may be removed manually or by a machine such as suction. Here, a method of applying tension in the direction in which the end of the flat portion of the molding substrate 1 is peeled off from the support 3 by a roller is exemplified.
<(V) Trimming process>
It is preferable that the manufacturing method of the fiber base material 1 which concerns on this invention further includes the trimming process of cut | disconnecting and dividing the said plane part (B) following process (IV). By trimming the fiber base material 1, the handleability of the fiber base material 1 in the manufacture of a molded product described later is improved.

The trimming method is not particularly limited, and a known slitter device such as a rotary cutter, a guillotine cutter, or a flying shear can be used.
<Molded product>
The molded product according to the present invention is obtained by integrating the fiber substrate 1 and the matrix resin (a).
<Matrix resin (a)>
Here, as a kind of matrix resin (a), a thermoplastic resin and a thermosetting resin can be illustrated. In the present invention, a thermosetting resin and a thermoplastic resin may be blended. Examples of the thermoplastic resin used in the matrix resin (a) in the present invention include “polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), liquid crystal polyester, etc. Polyolefins such as polyester, polyethylene (PE), polypropylene (PP), polybutylene, polyarylene sulfides such as polyoxymethylene (POM), polyamide (PA), polyphenylene sulfide (PPS), polyketone (PK), polyetherketone (PEK) ), Polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyethernitrile (PEN), polytetrafluoroethylene and other fluororesins, liquid crystal polymers LCP) "and other crystalline resins," Styrenic resin, polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene ether (PPE), polyimide (PI), polyamideimide (PAI) ), Polyetherimide (PEI), polysulfone (PSU), polyethersulfone, polyarylate (PAR) ", etc., phenolic resin, phenoxy resin, polystyrene, polyolefin, polyurethane Examples thereof include thermoplastic elastomers such as polyester-based, polyamide-based, polybutadiene-based, polyisoprene-based, fluorine-based resin, acrylonitrile-based, and the like, and copolymers and modified products thereof. Among them, polyolefin is preferable from the viewpoint of light weight of the obtained molded product, polyamide is preferable from the viewpoint of strength, amorphous resin such as polycarbonate and styrene resin is preferable from the viewpoint of surface appearance, and heat resistance is preferable. To polyarylene sulfide, polyether ether ketone is preferred from the viewpoint of continuous use temperature, and fluorine resin is preferably used from the viewpoint of chemical resistance.

  Examples of the thermosetting resin used in the matrix resin (a) in the present invention include unsaturated polyester, vinyl ester, epoxy resin, phenol resin, urea resin, melamine resin, thermosetting polyimide, copolymers thereof, and modified products. And a resin obtained by blending at least two of them.

In addition, the matrix resin (a) may contain an impact resistance improver such as an elastomer or a rubber component, and other fillers and additives as long as the object of the present invention is not impaired. Examples of fillers and additives include inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, and coloring inhibitors. , Heat stabilizers, release agents, antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, antifoaming agents, binders, or coupling agents.
<Manufacturing method>
The molded product according to the present invention can be obtained by integrating the fiber substrate 1 and the matrix resin (a). Usually, it is obtained as a molded article in which the fiber base material 1 is impregnated with a matrix resin, and examples thereof include a prepreg. There are no particular restrictions on the method of integration, but examples include press molding, RTM molding, Va-RTM molding, etc. The form of the matrix resin (a) used for the integration is not particularly limited, and the molten state, film It can be used in a state or a solid state (fiber, flake, particle, etc.). It is preferable to select the form of the matrix resin (a) in accordance with the integration method. For example, in press molding, the matrix resin (a) is preferably in the form of a solid or a film, more preferably in the form of a film, and it is preferable that the shape of the fiber substrate 1 is previously formed by vacuum molding or the like. . When integrating by RTM shaping | molding or Va-RTM shaping | molding, it is preferable to inject | pour into the type | mold with which the fiber base material 1 is arrange | positioned in the state which the matrix resin (a) melted.

  Further, the matrix resin (a) may be applied to the fiber substrate 1 in the above-described deposition step and / or fixing step. As a method to be applied, the matrix resin (a) is formed into a fibrous, flaky, or particulate form by mixing with the reinforcing fibers 4 in the deposition step or / and the fixing step, or alternately deposited and laminated. Examples are methods. When the matrix resin (a) is previously contained in the fiber base material 1 in the deposition step or / and the fixing step, a molded product can be efficiently obtained by heating and pressurizing the fiber base material 1 by press molding or the like. Therefore, it is preferable.

  The molded product is used for each industrial product. Examples of the use of the molded product include “PC, display, OA equipment, mobile phone, portable information terminal, PDA (mobile information terminal such as electronic notebook), video camera, acoustic equipment, optical equipment, audio, air conditioner, and lighting equipment. , Recreational equipment, toy goods, housings for other home appliances, trays, chassis, interior members, or cases thereof, etc., electrical parts, electronic parts, various members, various frames, various hinges, various arms, various axles, "Wheel bearings, various beams", "hood, roof, door, fender, trunk lid, side panel, rear end panel, front body, underbody, various pillars, various members, various frames, various beams, various supports, various rails" , Skins or body parts such as various hinges ”,“ bumpers, bumper beams, motors ” , Undercovers, engine covers, rectifying plates, spoilers, cowl louvers, aero parts and other exterior parts "," interior parts such as instrument panels, seat frames, door trims, pillar trims, handles, various modules "or" motor parts , CNG tanks, gasoline tanks ", etc., structural parts for motorcycles," battery trays, headlamp supports, pedal housings, protectors, lamp reflectors, lamp housings, noise shields, spare tire covers ", automobiles, motorcycle parts, Building materials such as `` sound insulation walls, sound barriers and other interior members '', aircraft parts such as `` landing gear pods, winglets, spoilers, edges, ladders, elevators, failings, ribs, seats, bodies of small unmanned aircraft '' `` Prosthetic limb Protectors, supporters, medical devices can be used such as the medical part of the shock absorbing member "or the like. From the viewpoint of mechanical properties, the molded product obtained by the production method of the present invention is preferably used for automobile interior / exterior, electrical / electronic equipment casing, bicycle, sports equipment structural material, aircraft interior material, transport box, and building material. Used. Especially, it is suitable for the module member comprised from a some component especially.

<Example>
Hereinafter, the present invention will be described in more detail with reference to examples.
(1) Fiber substrate thickness T, height Z
The cross section including the bent portion in the fiber base was observed with an optical microscope, and the thickness T and the height Z were determined from the observed image. The measurement was performed at n = 10, and the arithmetic average value was calculated.

[Carbon fiber 1]
Using a copolymer composed of 99.4 mol% of acrylonitrile (AN) and 0.6 mol% of methacrylic acid, an acrylic fiber bundle having a single fiber denier 1d and a filament number of 12,000 was obtained by a dry and wet spinning method. The obtained acrylic fiber bundle was heated at a draw ratio of 1.05 in air at a temperature of 240 to 280 ° C., converted to flame-resistant fiber, and then heated in a temperature range of 300 to 900 ° C. in a nitrogen atmosphere. After 10% stretching at a rate of 200 ° C./min, the temperature was raised to a temperature of 1,300 ° C. and baked. This carbon fiber bundle is subjected to an electrolytic surface treatment of 3 coulombs per gram of carbon fiber with an aqueous solution containing sulfuric acid as an electrolyte, further provided with a sizing agent by an immersion method, and dried in heated air at a temperature of 120 ° C. The PAN-based carbon fiber shown in FIG.
Total number of filaments 12,000 Single fiber diameter 7μm
Mass per unit length 0.8g / m
Density 1.8g / cm ³
Tensile strength (Note 1) 4.2 GPa
Tensile modulus (Note 2) 230 GPa
Sizing type Polyoxyethylene oleyl ether sizing adhesion amount (Note 3) 1.5% by mass
O / C (Note 4) 0.10
(Note 1) Tensile strength, (Note 2) Tensile modulus measurement conditions It was determined by the technique described in Japanese Industrial Standard (JIS) -R-7601 “Resin Impregnated Strand Test Method”. However, the resin-impregnated strand of carbon fiber to be measured is obtained by impregnating carbon fiber with “BAKELITE” (registered trademark) ERL 4221 (100 parts by mass) / 3 boron fluoride monoethylamine (3 parts by mass) / acetone (4 parts by mass). It was formed by curing at 130 ° C. for 30 minutes. The number of strands measured was 6, and the average value of each measurement result was the tensile strength and tensile modulus of the carbon fiber.
(Note 3) Measurement conditions for the amount of sizing agent attached As a sample, about 5 g of the carbon fiber to which the sizing agent was attached was collected and put into a heat-resistant container. The container was then dried at 120 ° C. for 3 hours. After being cooled to room temperature while taking care in a desiccator so as not to absorb moisture, the weighed mass was defined as W ₁ (g). Subsequently, after heating to 450 ° C. for 15 minutes in a nitrogen atmosphere together with the container and similarly cooling to room temperature while taking care not to absorb moisture in a desiccator, the weight weighed was defined as W ₂ (g). Through the above treatment, the amount of the sizing agent attached to the carbon fiber was determined by the following equation.
(Formula) Adhering amount (% by mass) = 100 × {(W ₁ −W ₂ ) / W ₂ }
In addition, the measurement was performed 3 times and the average value was employ | adopted as adhesion amount.
(Note 4) O / C measurement conditions It was determined by X-ray photoelectron spectroscopy according to the following procedure. First, carbon fibers from which deposits and the like were removed from the carbon fiber surface with a solvent were cut into 20 mm, and spread on a copper sample support table. A1Kα1 and 2 were used as the X-ray source, and the inside of the sample chamber was kept at 1 × 10 ⁸ Torr. The kinetic energy value (KE) of the main peak of C _1s was adjusted to 1202 cV as a peak correction value associated with charging during measurement. C _1s peak area E. It was obtained by drawing a straight base line in the range of 1191 to 1205 eV. O _1s peak area, E. As a linear base line in the range of 947 to 959 eV.

[Binder 1]
As the binder 1, "Polyment" (registered trademark) SK-1000 manufactured by Nippon Shokubai Co., Ltd. was used. The physical properties are as follows.
・ Acrylic polymer having aminoalkylene group in the side chain ・ Amine hydrogen equivalent 650 g / eq
・ Softening temperature 160 ℃
[PP resin sheet]
100 g of basis weight comprising 80% by mass of unmodified polypropylene resin (“Prime Polypro” (registered trademark) J105G manufactured by Prime Polymer Co., Ltd.) and 20% by mass of acid-modified polypropylene resin (“Admer” QB510 manufactured by Mitsui Chemicals, Inc.) / M ² sheet (melting point 160 ° C.) was prepared.

[Support 1]
The net-like support body in which the polygonal trapezoidal curved surface shown in FIG. 4 is continuously formed in the conveyance direction at two locations in the width direction.

[Support 2]
A net-like support composed only of a flat surface without a bent surface.

[Mold 1]
As a mold used for press molding, the mold 1 shown in FIG. 5A and the convex mold shown in FIG.
W1 = W2 = 200mm, W3 = 100mm, W4 = 50mm
W5 = W6 = 200 mm, W7 = 100 mm, W8 = 50 mm
D1 = 100 mm, D2 = 49.5 mm, D3 = 100 mm, D4 = 49.5 mm
Example 1
Carbon fiber 1 was cut into 5 mm with a cartridge cutter to obtain chopped carbon fiber. A dispersion having a concentration of 0.1% by mass composed of water and a surfactant (manufactured by Nacalai Tex Co., Ltd., polyoxyethylene lauryl ether (trade name)) is prepared, and the dispersion and the chopped carbon fiber are reinforced. The fiber base material 1 was manufactured using the manufacturing apparatus of a mat | matte.

  The manufacturing apparatus includes a cylindrical container having a diameter of 1000 mm having an opening cock at the bottom of the container as a deposition tank, and a linear transport section (inclination angle of 30 °) that connects the deposition tank and the papermaking tank. A stirrer is attached to the opening on the upper surface of the deposition tank, and chopped carbon fiber and dispersion liquid can be charged from the opening. A papermaking tank is a tank provided with a mesh conveyor having a support 1 at the bottom, and a conveyor capable of carrying a fiber base material is connected to the mesh conveyor. Papermaking was performed at a fiber concentration of 0.05% by mass in the dispersion. The paper-made fiber substrate was dried in a drying oven at 200 ° C. for 30 minutes.

  Subsequently, the opening cock of the binder tank is opened, and 200 g of an aqueous dispersion (emulsion) of 3% by mass of binder 1 as a binder is sprayed on the upper surface of the fiber base material flowing on the conveyor. did. The fiber base material 1 which gave the binder 1 by attracting | sucking the excess binder was obtained.

The fiber base material was dried by passing through a drying furnace having a length of 5 m at 200 ° C., then released from the support, and trimmed with a rotary cutter to obtain a fiber base material 1. The obtained fiber substrate 1 had a thickness T of 0.5 mm, a height Z of 30 mm, and a basis weight of 50 g / m ² .

(Comparative Example 1)
Production was carried out in the same manner as in Example 2 except that the binder was not used. In the demolding step, the fiber base material was broken without being peeled off from the support, and the fiber base material could not be obtained.

(Example 2)
Using the fiber substrate 1 produced in Example 1 as the fiber substrate, the mold 1 as the mold, and the PP resin sheet as the matrix resin, the following steps (I) to (V) are performed by press molding. Thus, a molded product was obtained. The thickness of the obtained molded product was 0.5 mm, and the molded product had a good glossy appearance.
(I) Two layers of PP resin sheet are preheated to 200 ° C., shaped into a mold by vacuum forming, cooled to 50 ° C. and taken out.
(II) Four layers of the fiber base material 1 produced in Example 1 and the PP resin sheet were placed in a press mold die cavity preheated to 140 ° C., the die was closed, and the temperature was raised to 200 ° C. .
(III) Next, after holding for 120 seconds, a pressure of 50 kN is applied and the pressure is further held for 60 seconds.
(IV) Thereafter, the cavity temperature is cooled to 50 ° C. while maintaining the pressure.
(V) Open the mold and take out the structure.

(Comparative Example 2)
A fiber substrate 2 was obtained in the same manner as in Example 1 except that the support was changed to the support 2. The obtained fiber substrate 2 had a thickness T of 0.5 mm, a height Z of 0.5 mm, and a basis weight of 50 g / m ² .
Using the fiber substrate and the PP resin sheet, a molded product was obtained through the following steps (I) to (IV). Although the thickness of the obtained molded product was 0.5 mm, the molded product was wrinkled on the fiber base material, and the fiber base material was torn at the bent portion, and the appearance quality was poor.
(I) A four-layer fiber base 2 and a two-layer PP resin sheet are placed in a press-molding mold cavity preheated to 140 ° C., the mold is closed, and the temperature is raised to 200 ° C.
(II) Next, after holding for 120 seconds, a pressure of 50 kN is applied and the pressure is further held for 60 seconds.
(III) Thereafter, the cavity temperature is cooled to 50 ° C. while maintaining the pressure.
(IV) Open the mold and take out the structure.

<Examination>
In Example 1, it was shown that the fiber base material which has a bending part can be obtained by this manufacturing method. Further, the comparison between Example 1 and Comparative Example 1 showed that the fixing state of the reinforcing fibers is important in the production of the fiber base material in the production method of the present invention.

  Moreover, while the fiber-reinforced resin molded product which has the bending part shape | molded using the planar fiber base material and resin sheet shown by the comparative example 2 is inferior to an external appearance quality, this invention shown by Example 2 is shown. The molded article using the fiber base material 1 manufactured by the manufacturing method according to the present invention has a good appearance, and it is clear that the fiber base material according to the manufacturing method of the present invention is suitable for forming a three-dimensional shape. It became.

  According to the method for producing a molded product according to the present invention, a press-molded product excellent in appearance quality such as wrinkles and lightness can be provided.

S: Cross section 1: Fiber base material 2: Cross section 3: Support body 4: Reinforcing fiber

Claims (11)

A method for producing a fiber base material having a bent portion (A),
The manufacturing method of a fiber base material including the process of at least following (I)-(IV).
(I) Cutting step for cutting the reinforcing fibers in a discontinuous manner (II) Deposition step (III) for depositing the reinforcing fibers on a net-like support having a bent surface (C) having the same shape as the bent portion (A). Fixing step of fixing the reinforcing fibers to each other with a binder (IV) Demolding step of removing the fiber substrate on which the bent portion (A) is formed along the bent surface (C) from the support.   The manufacturing method of the fiber base material of Claim 1 in which the said fiber base material has a plane part (B).   The fiber substrate according to claim 1 or 2, wherein Z> 3T, where Z is the height of the bent portion (A) in the cross section (S) having the bent portion, and T is the thickness of the fiber substrate. Manufacturing method.   The manufacturing method of the fiber base material in any one of Claims 1-3 whose said reinforced fiber is carbon fiber and whose mass mean fiber length is 1-15 mm.   The manufacturing method of the fiber base material in any one of Claims 1-4 in which the said support body has multiple bending surfaces (C).   The manufacturing method of the fiber base material in any one of Claims 1-5 with which the said deposition process is performed by a dry process.   The manufacturing method of the fiber base material in any one of Claims 1-5 with which the said deposition process is performed with a wet method.   In the said adhering process, the said reinforcement fibers are adhere | attached with the said binder using the at least 1 method chosen from the group which consists of press heating, vacuum heating, and oven heating. The manufacturing method of the fiber base material.   The method for producing a fiber substrate according to any one of claims 1 to 8, wherein the reinforcing fibers are substantially monofilaments and randomly dispersed at any point in the fiber substrate. The manufacturing method of the fiber base material in any one of Claims 1-9 further including the following processes (V) following the said process (IV).
(V) Trimming step of cutting and dividing the plane portion (B) The manufacturing method of the molded article obtained by integrating the fiber base material and matrix resin (a) in any one of Claims 1-10.

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