JP4984973B2 - Manufacturing method of fiber reinforced resin - Google Patents

Description

  The present invention relates to a method for producing a fiber reinforced resin (hereinafter sometimes referred to as FRP (Fiber Reinforced Plastic)), and more particularly, to a method for producing a fiber reinforced resin by an RTM molding method (Resin Transfer Molding).

  In the RTM molding method of the present invention, a double-sided mold that is a pair of upper and lower sides is used, and resin is injected under pressure from the resin injection port toward the resin discharge port. RTM molding method that closes the mold and pressurizes the resin to cure, RTM molding method that cures the resin by suction or pressure injection after the mold is evacuated, and the substrate is placed on the single-sided mold In addition, a vacuum RTM molding method is included in which after bagging with a bag material such as a film to decompress the inside, the resin is sucked and injected by the internal vacuum pressure.

  FRP is used in a very wide field as a composite material having a light weight and high mechanical properties. As one of such FRP molding methods, the RTM molding method is widely used. In the RTM molding method, the molding cycle time is relatively short, but defects such as pinholes and voids may remain on the surface of the molded product due to defects in resin flow, etc., so that it is intended to be applied to products that require good appearance. When doing so, a surface repair process etc. were required before the painting process. For these reasons, FRP manufactured by the RTM molding method is labor-intensive and labor-intensive to finish the appearance, and tends to be a high-cost product.

  Therefore, various studies have been made to solve the problems of the conventional RTM molding method. For example, in Patent Document 1, a laminate composed of a surface layer forming member / a separation base material having a high filtration resistance / a fibrous reinforcing material / a separation base material having a low filtration resistance / expandable resin particles in a mold used for RTM molding is molded. A molding method has been proposed in which the molding layer temperature is raised, the surface layer base material is pressed against the molding die by the volume expansion of the expandable particles, and a liquid molding resin is injected into the molding die to obtain a molded article with a high surface quality composite material. . However, in this method, it is essential to have a structure in which the foamable particles do not flow out to the surface layer with a separation substrate having a high filtration resistance, the layered structure is limited, and after the molding by heating to the foaming temperature of the foamable particles In order to prevent deformation of the molded product due to the foaming internal pressure of the particles, the temperature of the mold must be sufficiently lowered after the liquid resin is cured, resulting in problems such as an increase in equipment and a long molding cycle time.

Further, in Patent Document 2, by providing a random mat layer directly below the reinforcing fiber material that becomes the surface layer in the lamination, air bubbles in the reinforcing fiber substrate are removed, and impregnation of the resin into the reinforcing fiber substrate of the surface layer is performed. Promoting molding methods have been proposed. However, in this method, since the random mat layer is disposed directly under the surface layer base material, bubbles contained in the resin may accumulate in the random mat layer, resulting in a pinhole penetrating the surface layer base material immediately above.
Japanese Patent Application Laid-Open No. 7-100847 JP-A-2005-232601

  The purpose of the present invention is to reduce the surface defects such as pinholes that have occurred on the surface layer in the conventional RTM molding method, and to reduce the repair process required for the subsequent painting process, etc., thereby improving the productivity of the molded product. It is to improve.

  As a result of various investigations to solve the above-mentioned problems, by providing an intermediate layer having a specific cover factor and a resin diffusion layer having a specific impregnation property, there is almost no pinholes on the surface of the molded product, and surface quality is improved. It was found that an excellent RTM molded product can be obtained, and the present invention has been completed.

That is, the method for producing a fiber reinforced resin according to the present invention is a method for producing a fiber reinforced resin in which at least a reinforced fiber base is disposed in a pair of mold cavities, and the resin is injected into the cavity and cured. At least one surface of the reinforcing fiber base material, a surface layer forming base material that is in direct contact with at least one inner surface of the mold, and the surface layer forming base material positioned between the surface layer forming base material and the reinforcing fiber base material A resin diffusion medium comprising a mesh having an impregnation coefficient ratio of 1.5 to 10 with a material is disposed via an intermediate layer comprising at least one woven fabric having a cover factor of 90% to 100%, and A core material is disposed on at least a part of the resin diffusion medium facing the reinforcing fiber substrate, and an impregnation coefficient is 1 × 10 ⁻¹⁰ m ² or more at least on an end portion on the resin injection side of the core material . Thickness Consists method characterized by providing a resin flow substrate 50 to 2000 m.

  In such an RTM molding method in the present invention, by disposing a specific intermediate layer and a resin diffusion medium in the laminated structure, bubbles mixed with the resin injection are first introduced in the resin diffusion medium having good resin fluidity. By mainly flowing together with the resin, it can be discharged well or stay in the resin diffusion medium layer, and an intermediate layer having a predetermined range of cover factor is provided between the outermost layer and the resin diffusion medium. This makes it possible to prevent the bubbles staying in the resin diffusion medium from being exposed to the surface of the molded product. On the other hand, since the resin can be included in the resin diffusion medium and the resin can be impregnated by supplying resin with less bubbles from the resin diffusion medium to the surface layer side base material, a design that has been difficult with the conventional RTM molding method A molded product in which defects such as surface voids and pinholes are extremely small can be efficiently and stably molded in a short time.

  In the method for producing a fiber reinforced resin according to the present invention, it is possible to adopt a form in which at least one end portion of the resin diffusion medium is extended outward from at least one adjacent layer. By making at least one end of the resin diffusion medium longer than at least one adjacent layer, it becomes easy for the injected resin to enter and expand into the resin diffusion medium from the long end, and the resin diffuses reliably. To be fed into the layer of media. As a result, the resin reliably reaches the inside of the laminate, and the resin impregnation property for the entire laminate is greatly improved.

The impregnation coefficient of the resin diffusion medium is preferably 1 × 10 ⁻¹⁰ m ² or more. The impregnation coefficient is a coefficient representing the ease of impregnation of the resin, and the measurement method will be described later. By using a resin diffusion medium having a high impregnation coefficient, the resin can be easily developed to a desired range, the impregnation property of the developed resin is improved, and the end portion is formed long. The effect is expressed even better.

  The thickness of the resin diffusion medium is preferably in the range of 200 to 2000 μm. Since it is preferable that the resin diffusion medium has a high impregnation coefficient as described above, by using a base material having such a high impregnation coefficient, a sufficient amount of resin can be transferred from the end of the resin diffusion medium to the center or the opposite side. It becomes possible to make it flow toward the end of the. However, if the resin diffusion medium is too thin, it becomes difficult to flow a sufficient amount of resin, and if it is too thick, it becomes difficult to maintain a desired laminated form as a whole laminate. Therefore, the thickness is preferably in the range of 200 to 2000 μm.

Further, in the method for producing a fiber reinforced resin according to the present invention, a core material is disposed on at least a part of the resin diffusion medium facing the reinforcing fiber base , and at least an end of the core material on the resin injection side. Further, it is possible to adopt a form in which a resin fluidized substrate having an impregnation coefficient of 1 × 10 ⁻¹⁰ m ² or more and a thickness of 50 to 2000 μm is provided. This resin fluid base material should just be arrange | positioned only at the edge part of a core material, and does not need to cover the whole surface of a core material. Moreover, although it should just be arrange | positioned at at least one edge part in the resin flow direction, it arrange | positions desirably at both ends. As described above, the specific resin flow base material layer is arranged at the end of the core material, so that the resin flow at the end of the core material is extremely stable, and it has been easy to reach the surface of the molded body from this part conventionally. The air bubbles are finely dispersed inside the molded body and contained, and are not easily exposed on the surface. As a result, the surface quality of the molded body is greatly improved.

The resin fluid base material needs to have an impregnation coefficient of 1 × 10 ⁻¹⁰ m ² or more. That is, by using a resin fluidized base material having a high impregnation coefficient, the resin flow stabilization, the bubble dispersion, and the containment effect are further improved.

  It is also preferable that at least one surface of the core material is grooved. Due to the presence of the core groove, the diffusion resin by the resin diffusion medium is diffused more quickly and uniformly, and in combination with the action by the resin flow base disposed at the end of the core material, bubbles are locally generated. Is prevented from staying or growing, and more uniform molding becomes possible.

  As described above, according to the method for producing a fiber reinforced resin according to the present invention, by arranging the specific intermediate layer and the resin diffusion medium in the laminated structure, the bubbles staying in the resin diffusion medium layer are transferred to the surface of the molded product. The exposure can be effectively prevented, and a molded product in which defects such as voids and pinholes are hardly generated on the surface can be molded efficiently and stably in a short time. As a result, even in a manufacturing process in which there is a painting process as a subsequent process, the surface repair process can be omitted or greatly reduced, and a low-cost molded product can be obtained.

  Hereinafter, the present invention will be described in detail together with preferred embodiments.

  FIG. 1 shows an example of a basic form of a method for producing a fiber reinforced resin according to the present invention. In the cavity 1 of the mold 2 composed of the upper mold 2a and the lower mold 2b, the reinforcing fiber base material 3 is disposed. In this embodiment, the surface layer forming base materials 4a and 4b are provided on both sides of the reinforcing fiber base material 3; Resin diffusion media 5a and 5b, which are located between the surface layer forming substrates 4a and 4b and the reinforcing fiber substrate 3 and have an impregnation coefficient ratio of 1.5 to 10 with the surface layer forming substrates 4a and 4b; Are arranged via intermediate layers 6a, 6b made of a woven fabric having a cover factor of 90% to 100%. In this state, the inside of the cavity 1 is depressurized by vacuum suction, for example, as indicated by an arrow 7, and resin is injected into the cavity 1 that has been reduced in pressure as indicated by an arrow 8. After the substrate is impregnated, it is cured, for example, by heating, and a predetermined fiber-reinforced resin molded body is manufactured.

  Examples of the resin used in the present invention include thermosetting resins such as epoxy resins, vinyl ester resins, unsaturated polyester resins, and phenol resins, acrylic resins, polyamide resins, and polyolefin resins. In particular, a resin having a low viscosity such that the viscosity at room temperature is 10 Pa · s or less and a good impregnation of fibers is preferable.

  The reinforcing fiber base in the present invention is a general term for bases made of reinforcing fibers other than the surface layer forming base, intermediate layer base, and resin diffusion medium base to be described later. Examples of the reinforcing fiber used for the reinforcing fiber substrate in the present invention include carbon fiber, glass fiber, aramid fiber, PBO (polyparaphenylene benzobisoxazole) fiber, tyrano (titanium alumina) fiber, and nylon fiber. In addition, the woven structure may be woven or non-woven, and in the case of woven cloth, plain weave, twill weave, satin weave, etc. are mentioned, and it is not only composed of a single fiber but also woven with a plurality of fibers. May be. In the case of a nonwoven fabric, for example, a random mat or a continuous strand mat can be used.

  The surface layer forming base material in the present invention is a base material that is disposed on the outermost layer of the molded product, and is a base material that satisfies an impregnation coefficient ratio with a resin diffusion medium described later. Examples of the fiber used for the surface layer forming substrate in the present invention include carbon fiber, glass fiber, aramid fiber, PBO (polyparaphenylene benzobisoxazole) fiber, tyrano (titanium alumina) fiber, and nylon fiber. In addition, the woven structure may be woven or non-woven, and in the case of woven cloth, plain weave, twill weave, satin weave, etc. are mentioned, and it is not only composed of a single fiber but also woven with a plurality of fibers. May be. In the case of a nonwoven fabric, a random mat is mentioned, for example.

  The resin diffusion medium in the present invention is a layer having a higher impregnation coefficient than other base materials so that the resin in the resin diffusion medium layer can easily flow. It is a base material that satisfies an impregnation coefficient ratio with a surface layer forming base material to be described later.

  For forming the resin diffusion medium, a mesh or a fiber base material can be used. Examples of the material of the mesh include nylon resin, polypropylene resin, polyethylene resin, and the like, and a material that has been subjected to plasma treatment or corona treatment to improve adhesion as necessary may be used. In the case of using a fiber base material, examples of the fiber used include carbon fiber, glass fiber, aramid fiber, PBO (polyparaphenylene benzobisoxazole) fiber, tyrano (titanium alumina) fiber, and nylon fiber. In addition, the woven structure may be woven or non-woven, and in the case of woven cloth, plain weave, twill weave, satin weave, etc. are mentioned, and it is not only composed of a single fiber but also woven with a plurality of fibers. May be. In the case of a nonwoven fabric, for example, a random mat or a continuous strand mat can be used.

  The intermediate layer in the present invention is a textile base material having a high cover factor of 90% to 100% so that bubbles in the resin flowing in the resin diffusion medium do not reach the outer layer.

  Examples of fibers used for the fabric base material of the intermediate layer include carbon fibers, glass fibers, aramid fibers, PBO (polyparaphenylene benzobisoxazole) fibers, tyrano (titanium alumina) fibers, and nylon fibers. The base material structure is preferably a woven fabric, and includes plain weave, twill weave, satin weave, and the like, and may be composed of not only a single fiber but also a plurality of fibers.

  In the present invention, the surface layer forming base material and the resin flow medium are composed of base material layers having different impregnation coefficients, and the impregnation coefficient ratio shown in the following formula is 1.5 to 10 after molding. It is necessary to obtain an appearance with few defects such as a hole shape having a diameter of 0.2 mm to 2 mm and a depth of 0.2 mm to 1 mm on the surface. When this impregnation coefficient ratio is lower than 1.5, there is substantially no difference in resin flow, and the resin containing air bubbles also flows to the surface layer forming substrate side, and it is easy to form pinholes on the external surface. Become. On the other hand, when the impregnation coefficient ratio is more than 10, there are few pinholes on the appearance surface, but the amount of resin impregnation increases, which may increase the weight of the molded product.

Impregnation coefficient ratio = K1 / K2
here,
K1: The largest value of the impregnation coefficient of the base material among the laminated structures (impregnation coefficient of the resin diffusion medium layer)
K2: The smallest value of the impregnation coefficient of the base material among the laminated configurations. Here, the resin impregnation coefficient is a value measured by the following measuring method.

  In the resin impregnation process, it is known that the behavior of the resin impregnated into the base material follows the Darcy law shown in the following equation, and the impregnation rate is obtained by the following equation.

v = (K / μ) × (ΔP / ΔL) (1)
Here, v (m / s) is the impregnation rate, K (m ² ) is the impregnation coefficient, μ is the resin viscosity (Pa · s), ΔP (Pa) / ΔL (m) is the pressure gradient per unit length. is there. If this equation is integrated over time t (s), the impregnation coefficient can be obtained by the following equation.

K = (L × L × μ) / (2 × P × t) (2)
Here, L (m) is the distance from the resin inlet to the flow front (the tip of the fluid resin). If the distance from the resin inlet to the flow front, the arrival time there, the resin viscosity, and the molding pressure are known from the equation (2), the impregnation coefficient can be calculated. Therefore, the impregnation coefficient can be measured by conducting an impregnation coefficient measurement experiment on a basic shape such as a flat plate using an apparatus as shown in FIG. 2 as an example, and measuring these to measure the impregnation coefficient K.

  In the present invention, when measuring the impregnation coefficient, for example, an impregnation coefficient measuring apparatus 11 as shown in FIG. 2 is used. By maintaining the pressure inside the device 11 at a gauge pressure higher than -100 kPa, the pressure ΔP is set to 100 kPa. In the measurement, it is preferable to measure at the molding temperature using an actual resin, but if the resin viscosity at the molding temperature is known in advance, a liquid adjusted to the viscosity, such as silicon oil or ether type It can also be measured using synthetic oil or the like. In the present invention, the distance L from the resin middle entrance to the flow front is set to 500 mm, and the time t when the resin reaches at this time is measured with a digital stopwatch capable of measuring up to 1/100 sec. Further, these measurements are performed by calculating an impregnation coefficient using an average value obtained three times in total. In FIG. 2, 12 is a resin tank, 13 is a vacuum pump, 14 is a base material, 15 is an injection port, 16 is a discharge port, and an arrow 17 indicates a resin impregnation direction.

  As a textile base material used for the intermediate layer in the present invention, a base material having a cover factor of 90% to 100% is used. By disposing one or more base materials having a high cover factor of 90% or more in the intermediate layer, it is difficult for air bubbles to flow out from the resin flow medium to the surface layer forming base material, and a molded body with few pinholes in appearance can be obtained. .

  Here, the cover factor indicates the ratio of the fiber area per unit area, and is measured by the following procedure when the base material is a woven fabric. The target substrate is enlarged by a copying machine or the like, and the vertical dimension Y and the horizontal dimension X per 10 fiber bundles are measured. The enlargement with the copying machine at this time is performed so that the lateral dimension per 10 fiber bundles is 100 ± 5 mm, and measurement is performed using calipers capable of displaying up to 0.01 mm. Next, the width of each of the ten fiber bundles is 30 pitches with a pitch of X / 2 for each longitudinal fiber and a total of 30 points for each fiber bundle, and a pitch of Y / 2 for lateral fibers. Then, a total of 30 points of three fibers are measured, and the longitudinal fiber width average value x and the transverse fiber width average value y are calculated. The cover factor Cf is expressed by the following formula.

Cf = {Y * x + (X−x) * y} / (X * Y)
The thickness of the resin diffusion medium used in the present invention is preferably 200 to 2000 μm because a molded article having good appearance can be obtained. If it is thinner than 200 μm, the passage of bubbles inside the resin is hindered, and it becomes easy to form a void pool near the resin injection port. If it is thicker than 2000 μm, more voids can be accumulated in the layer, but the weight as a molded body. Increases and the effect of weight reduction is lost. In addition, in order to obtain the resin diffusion medium having such a thickness, for example, when a glass fiber mat is used, it can be realized by using a 200 to 900 g / m ² (a plurality of sheets may have this basis weight). . In addition, the resin diffusion medium should just satisfy the said thickness, even if it comprises only one layer in a molded object, or it comprises multiple layers.

Moreover, the resin is mainly a resin diffusion medium by setting the impregnation coefficient of the base material used for the resin diffusion medium layer to 1 × 10 ⁻¹⁰ m ² or more, for example, 1 × 10 ⁻¹⁰ to 1 × 10 ⁻⁹ m ^2. Since the bubbles in the resin that flow into the layer and adversely affect the appearance are easily stayed in the resin diffusion medium layer, it is possible to obtain a molded article having a good appearance. From this point of view, the upper limit is preferably as long as the coefficient is large, but the above-mentioned ranges are listed as currently available. Furthermore, when a thing with a larger impregnation coefficient becomes available, it can apply preferably.

  Further, as described above, the material used for the resin diffusion medium may be a mesh, a woven fabric, or a non-woven fabric. However, if a non-woven fabric such as a glass fiber chopped mat or a continuous strand mat is used, a low-cost molded product is used. Moreover, it becomes easy to accumulate a void in a layer.

  In the present invention, a form in which at least one end of the resin diffusion medium extends outward from at least one adjacent layer may be adopted. The resin diffusion medium may be extended at both ends, or may be a combination of an extended form at each end or a form having a different relationship with the adjacent layer. For example, as shown in FIG. It is also possible to adopt a form in which the end portion of the first protrusion protrudes from both adjacent layers 22a and 22b, and the other end protrudes only from the adjacent layer 22b. L1 and L2 indicate the protruding length of the resin diffusion medium 21 as long as it extends outward from at least one adjacent layer. The protrusion length is desirably 1 mm or more, and preferably in the range of 1 mm to 30 mm. In this way, by making at least one end of the resin diffusion medium longer than at least one adjacent layer, the injected resin can easily enter and expand into the resin diffusion medium from the long end, and the resin is more It is surely supplied into the layer of the resin diffusion medium.

Moreover, when a core material is arrange | positioned in at least one part of the side which faces the reinforced fiber base material of a resin diffusion medium, there exists a possibility that a bubble may reach easily from the edge part site | part of this core material to the surface of a molded object. Therefore, in the present invention, for example, as shown in FIG. 4, the impregnation coefficient is 1 × between the resin diffusion medium 32 at least at the end of the core material 31 on the resin injection side (at both ends in the illustrated example). It is necessary to provide a resin flowable substrate 33 having a thickness of 10 ⁻¹⁰ m ² or more and a thickness of 50 to 2000 μm. The resin fluid base material 33 may be disposed only at the end of the core material 31, and does not need to cover the entire surface of the core material 31. By arranging such a specific resin flow base material 33 at the end portion of the core material 31, the resin flow at the end portion of the core material 31 is extremely stable, and it is easy to reach the surface of the molded body from this portion. The air bubbles are finely dispersed inside the molded body and contained, and are not easily exposed on the surface. As a result, the surface quality of the molded body is greatly improved. In FIG. 4, reference numeral 34 denotes an intermediate layer, and 35 denotes a surface layer forming substrate.

As described above, the resin flow base material 33 preferably has an impregnation coefficient of 1 × 10 ⁻¹⁰ m ² or more. Further, it is also preferable that the groove 36 is processed on at least one surface of the core material 33. Due to the presence of the core groove 36, the diffusion resin by the resin diffusion medium 32 is diffused more quickly and uniformly.

  Thus, according to the method for producing a fiber reinforced resin according to the present invention, the bubble component present in the resin is mainly passed through the resin diffusion medium layer, and the bubbles are formed on the surface of the molded body by the specific intermediate layer. Since the form is difficult to reach, it is possible to reduce the need for post-processing such as repair and to obtain a molded article of fiber reinforced resin excellent in surface quality with almost no pinholes in appearance.

The fiber reinforced resin obtained as described above can be made into a carbon fiber reinforced plastic (CFRP) excellent in light weight, high strength, high elasticity, and impact resistance by using carbon fiber as the reinforcing fiber. It is used as a CFRP member suitable for automobiles, pressure vessels, aircraft structural materials, marine structural materials, golf club shafts, ski poles, fishing rods, and the like. The CFRP member includes reinforcing fibers other than carbon fibers (for example, glass fibers, aramid fibers, PBO (polyparaphenylene benzobisoxazole) fibers, as long as light weight, high strength, high elasticity, and impact resistance are not impaired. , Tyranno (titanium alumina) fiber, nylon fiber, etc.), if the reinforcing fiber other than carbon fiber is less than 50% by mass of the entire reinforcing fiber, it is included in the CFRP member here. Shall.
Furthermore, the CFRP member is preferably used as a member for automobiles that require mass production with a particularly short molding cycle.

  Below, it demonstrates more concretely based on an Example.

The materials used in the examples are as follows.
Substrate a: carbon fiber woven fabric, CO 6343B manufactured by Toray Industries, Inc. (woven structure: plain weave, fabric weight: 198 g / m ² , reinforcing fiber: T300B-3K, elastic modulus: 230 GPa, strength: 3530 MPa, fineness: 198 tex, filament Number: 3000), Cover factor = 95-97%
-Substrate b: carbon fiber fabric, BT70-30 manufactured by Toray Industries, Inc. (woven structure: plain weave, fabric weight: 317 g / m ² , reinforcing fiber: T700SC-12K, elastic modulus: 230 GPa, strength: 4900 MPa, fineness: 800 tex , Number of filaments: 12,000), cover factor = 96-98%
Substrate c: carbon fiber fabric, BT70-20 manufactured by Toray Industries, Inc. (woven structure: plain weave, fabric weight: 214 g / m ² , reinforcing fiber: T700SC-12K, elastic modulus: 230 GPa, strength: 4900 MPa, fineness: 800 tex , Number of filaments: 12,000), cover factor = 93 to 96%
Substrate d: Glass fiber surface mat, MF30P100BS6 manufactured by Nittobo Co., Ltd. (form of fabric: continuous fiber nonwoven fabric, basis weight: 30 g / m ² )
-Substrate e: carbon fiber mat, “Torayca” (registered trademark) T700SC (elastic modulus: 230 GPa, strength: 4900 MPa, fineness: 1650 tex) manufactured by Toray Industries, Inc. (cut length: 2 inches at maximum) 1 cm), basis weight: 80 g / m ² )
-Substrate f: Continuous strand mat, manufactured by Nippon Sheet Glass Co., Ltd. (fabric form: glass continuous fiber nonwoven fabric, basis weight: 450 g / m ² )
-Substrate g: Mesh sheet NB20 (manufactured by NBC Corporation: nylon mesh, thickness 520 μm)
-Substrate h: Glass woven fabric, E10T manufactured by Unitika Glass Fiber Co., Ltd. (weight per unit: 106 g / m ² , weaving density: length = 60/25 mm, width = 58/25 mm)
-Substrate i: Glass fiber nonwoven fabric, Super wool mat YWN-8 manufactured by Yazawa Sangyo Co., Ltd. (form of fabric: felted nonwoven fabric, basis weight: 720 g / m ² )
Substrate a ′: Substrate in which 10 ± 3 g / m ^{2 of} an epoxy-modified thermoplastic resin having a melting point of 71 ° C. is previously attached to the substrate a • Substrate b ′: Epoxy-modified thermoplastic having a melting point of 71 ° C. on the substrate b Substrate / Substrate c ′ with 5 ± 3 g / m ^{2 of} Resin Adhered: Substrate with 5 ± 3 g / m ² of epoxy-modified thermoplastic resin having a melting point of 71 ° C. adhered to the substrate c.
Core material a: “Formac” HR # 1006 (heat resistant acrylic resin foam) manufactured by Sekisui Chemical Co., Ltd., density = 0.1 g / cm ³ , thickness = 6 mm
-Resin a: Toray Industries, Inc., epoxy resin TR-C35
Main agent: “Epicoat” 828 (epoxy resin manufactured by Yuka Shell Epoxy)
Curing agent: Blend TR-C35H (imidazole derivative) manufactured by Toray Industries, Inc.
Mixing ratio: Main agent: Curing agent = 10: 1
Resin viscosity at 100 ° C .: 17 mmPa · s (value measured at 30 ° C., 50 ° C. and 70 ° C. using an E-type viscometer and converted based on the WLF equation).

[Example 1]
6 is disposed in a molding lower mold 42 having a 480 mm × 480 mm cavity 41 having the shape shown in FIG. 5, and the reinforcing fiber base (51a, 51b, 51c, 51d) shown in FIG. Do not close the upper mold. The structure of each base material such as the reinforcing fiber used here is as follows.

Surface layer forming base material 31a: base material a (0 ° / 90 ° fiber orientation) × 1Ply
Intermediate layer substrate 31b: substrate a (0 ° / 90 ° fiber orientation) × 1Ply
Resin diffusion medium layer substrate 31c: substrate f × 1Ply
Reinforcing fiber substrate 31d: substrate a (0 ° / 90 ° fiber orientation) × 2Ply
The impregnation coefficient of the base material a and the base material f was measured by the apparatus shown in FIG. In the measurement, the following numerical values were obtained when the measurement was performed at 25 ° C. using a liquid having a viscosity approximately equal to the viscosity of the resin a at a molding temperature of 100 ° C.

Impregnation coefficient K of substrate a = 0.6 × 10 ⁻¹⁰ m ²
Impregnation coefficient K of substrate f = 3.1 × 10 ⁻¹⁰ m ²
Therefore, the impregnation coefficient ratio at this time was 5.2.

  Next, with the molding lower mold 42 and the upper mold kept at a temperature of 100 ° C. and kept in a vacuum state, the resin a was injected from the resin injection port 44 using a resin injection machine (not shown). It was visually confirmed that the resin discharged from the resin discharge port 45 did not contain bubbles exceeding φ2 mm, the resin discharge port 45 was closed, and then the resin injection port 44 was closed. The maximum injection pressure applied to the resin at this time was 0.75 MPa.

  After holding in this state for 15 minutes, the mold was opened to obtain a molded product. After cooling the obtained molded product to 25 ° C., about the plate thickness of this molded product, 15 mm inside from the edge of the molded product, one corner at each corner and the center of each side, a total of 8 places on a micrometer Measured to be about 2.1 mm on average.

  Next, the surface of the obtained molded product was polished with # 600 sanding paper, degreased with acetone, applied with a primer for FRP (manufactured by Musashi Holt), and dried at room temperature for 1 hour. Thereafter, the number of pinholes on the surface having a diameter exceeding 0.2 mm was counted visually while applying the light of a fluorescent lamp to the surface of the molded product, and there were no pinholes. When the product was cut out and the thickness of each layer was measured, the base material 51c of the resin diffusion medium layer was about 1.1 mm on average.

[Example 2]
A molded product was obtained in the same manner as in Example 1 except that the configuration of each reinforcing fiber substrate was as follows.

Surface layer forming substrate 51a: substrate b ′ (0 ° / 90 ° fiber orientation) × 1Ply
Intermediate layer substrate 51b: substrate c ′ (0 ° / 90 ° fiber orientation) × 1Ply
Resin diffusion medium layer substrate 51c: substrate f × 1Ply
Reinforcing fiber substrate 51d: substrate c ′ (0 ° / 90 ° fiber orientation) × 2Ply
The impregnation coefficient of each substrate at this time is shown below.

Impregnation coefficient K = 0.66 × 10 ⁻¹⁰ m ^{2 of} substrate b ′
Impregnation coefficient K of base material f = 3.1 × 10 ⁻¹⁰ m ²
Impregnation coefficient K = 0.63 × 10 ⁻¹⁰ m ^{2 of} substrate c ′
Therefore, the impregnation coefficient ratio at this time was 4.7. The plate thickness of the obtained molded product was measured with a micrometer at a total of 8 locations, 15 mm inside from the edge of the molded product, one at each corner and at the center of each side. It was 2 mm.

  Next, after the surface treatment of the molded product was performed in the same manner as in Example 1, the number of pinholes on the surface with a diameter exceeding 0.2 mm was visually counted while applying the light of a fluorescent lamp to the surface of the molded product. There was no hall. Moreover, when the product was cut out and the thickness of each layer was measured, the thickness of the base material 51c of the resin diffusion medium layer was about 1.0 mm.

[Example 3]
A molded product was obtained in the same manner as in Example 1 except that the configuration of each reinforcing fiber substrate was as follows.

Surface layer forming substrate 51a: substrate h (0 ° / 90 ° fiber orientation) × 1Ply
Intermediate layer substrate 51b: substrate b (0 ° / 90 ° fiber orientation) × 2Ply
Resin diffusion medium layer substrate 51c: substrate g × 1Ply
Reinforcing fiber substrate 51d: substrate b (0 ° / 90 ° fiber orientation) × 1Ply
The impregnation coefficient of each substrate at this time is shown below.

Impregnation coefficient K of substrate h = 0.58 × 10 ⁻¹⁰ m ²
Impregnation coefficient K of substrate g = 2.3 × 10 ⁻¹⁰ m ²
Impregnation coefficient K of substrate c = 0.62 × 10 ⁻¹⁰ m ²
Therefore, the impregnation coefficient ratio at this time was 4.0. The plate thickness of the obtained molded product was measured with a micrometer at a total of 8 locations, 15 mm inside from the edge of the molded product, one at each corner and at the center of each side. It was 2 mm.

  Next, after the surface treatment of the molded product was performed in the same manner as in Example 1, the number of pinholes on the surface with a diameter exceeding 0.2 mm was visually counted while applying the light of a fluorescent lamp to the surface of the molded product. There was no hall. Moreover, when the product was cut out and the thickness of each layer was measured, the thickness of the base material 51c of the resin diffusion medium layer was about 0.9 mm.

[ Reference example]
A molded product was obtained in the same manner as in Example 1 except that the configuration of each reinforcing fiber substrate was as shown in FIG.

Surface layer forming base material 61a: Base material a (0 ° / 90 ° fiber orientation) × 1Ply
Intermediate layer base material 61b: base material a (0 ° / 90 ° fiber orientation) × 1Ply
Resin diffusion medium layer substrate 61c: substrate f × 1Ply
Reinforcing fiber substrate 61d: substrate f × 1Ply
Core material 61e: Core material a
The impregnation coefficient of each substrate at this time is shown below.

Impregnation coefficient K of substrate a = 0.6 × 10 ⁻¹⁰ m ²
Impregnation coefficient K of substrate f = 3.1 × 10 ⁻¹⁰ m ²
Therefore, the impregnation coefficient ratio at this time was 5.2. When the plate thickness of the center part 72a of the end portion of the molded product 71 shown in FIG. 8 obtained in the same manner as in Example 1 was measured, it was about 3.2 mm. Further, the thickness of the central portion 72b was measured and found to be about 9.3 mm.

  Next, after the surface treatment of the molded product was performed in the same manner as in Example 1, the number of pinholes on the surface with a diameter exceeding 0.2 mm was visually counted while applying the light of a fluorescent lamp to the surface of the molded product. There was no hall. Further, when the product was cut out and the thickness of each layer was measured, the reinforcing fiber bases 61b and 61d at the central portion 72b were each about 1.0 mm.

[Comparative Example 1]
A molded product was obtained in the same manner as in Example 1 except that the configuration of each reinforcing fiber substrate was as follows.

Reinforcing fiber substrate 51a: substrate a (0 ° / 90 ° fiber orientation) × 1Ply
Reinforcing fiber substrate 51b: substrate d × 1Ply
Reinforcing fiber substrate 51c: substrate a (0 ° / 90 ° fiber orientation) × 3Ply
The impregnation coefficient of each substrate at this time is shown below.

Impregnation coefficient K of substrate a = 0.6 × 10 ⁻¹⁰ m ²
Impregnation coefficient K of substrate d = 1.3 × 10 ⁻¹⁰ m ²
Therefore, the impregnation coefficient ratio at this time was about 2.2. When the plate thickness of the molded product obtained in the same manner as in Example 1 was measured, it was about 1.1 mm on average.

  Next, after the surface treatment of the molded product was carried out in the same manner as in Example 1, the number of pinholes on the surface having a diameter exceeding 0.2 mm was visually counted while applying fluorescent light to the surface of the molded product. 21 pinholes were confirmed on the fiber substrate 51a side, and 33 pinholes were present on the reinforcing fiber substrate 51c side. When the product was cut out and the thickness of each layer was measured, the base material 51c of the resin diffusion medium layer was about 0.03 mm on average.

  The method for producing a fiber reinforced resin according to the present invention can be suitably applied to, for example, an outer plate part typified by an automobile bonnet and a motorcycle cowl, a desk top board, a chair, etc. It is not limited to.

It is a schematic block diagram which shows an example of the basic form of the manufacturing method of the fiber reinforced resin which concerns on this invention. It is a schematic block diagram of an impregnation coefficient measuring device. It is a schematic block diagram which shows an example in the case of extending the edge part of the resin diffusion medium in the manufacturing method of the fiber reinforced resin which concerns on this invention. It is a schematic block diagram which shows an example in the case of providing a resin fluid base material in the edge part of a core material in the manufacturing method of the fiber reinforced resin which concerns on this invention. FIG. 2 is a perspective view of a lower mold used in Example 1. 1 is a schematic perspective view showing a laminated configuration of a base material used in Example 1. FIG. It is a schematic perspective view which shows the laminated structure of the base material used by the reference example . It is a schematic perspective view which shows an example of the molded article in this invention.

Explanation of symbols

1: Cavity 2a: Upper mold 2b: Lower mold 3: Reinforcing fiber substrate 4a, 4b: Surface layer forming substrate 5a, 5b: Resin diffusion medium 6a, 6b: Intermediate layer 11: Impregnation coefficient measuring device 12: Resin tank 13 : Vacuum pump 14: Base material 15: Injection port 16: Discharge port 17: Impregnation direction 21: Resin diffusion media 22 a and 22 b: Adjacent layer 31: Core material 32: Resin diffusion media 33: Resin fluid base material 34: Intermediate layer 35 : Surface layer forming substrate 36: Groove 41: Cavity 42: Lower mold 43: Sealing material 44: Injection port 45: Discharge port 51 a: Surface layer forming substrate 51 b: Intermediate layer substrate 51 c: Resin diffusion medium substrate 51d: Reinforced fiber substrate 61a: Surface layer forming substrate 61b: Intermediate layer substrate 61c: Resin diffusion medium substrate 61d: Reinforced fiber substrate 61e: Core material 71: Molded product 72a: End center thickness measurement Position 72b: Center thickness measurement Location

Claims (7)

A method for producing a fiber reinforced resin in which at least a reinforcing fiber base is disposed in a pair of mold cavities, and a resin is injected into the cavity and cured, and at least one of the molds is formed on at least one side of the reinforcing fiber base. An impregnation coefficient ratio of the surface layer forming base material that is in direct contact with the inner surface, and the surface layer forming base material that is located between the surface layer forming base material and the reinforcing fiber base material is 1.5 to 10 The resin diffusion medium made of mesh is disposed via an intermediate layer made of at least one woven fabric having a cover factor of 90% to 100%, and the resin diffusion medium on the side facing the reinforcing fiber base of the resin diffusion medium A core material is disposed at least in part, and a resin fluid base material having an impregnation coefficient of 1 × 10 ⁻¹⁰ m ² or more and a thickness of 50 to 2000 μm is provided at least on an end of the core material on the resin injection side. A method for producing fiber reinforced resin. The method for producing a fiber reinforced resin according to claim 1, wherein at least one end of the resin diffusion medium is extended outward from at least one adjacent layer. The manufacturing method of the fiber reinforced resin of Claim 1 or 2 whose impregnation coefficient of the said resin diffusion medium is 1 * 10 < ^-10 > m < ² > or more. The manufacturing method of the fiber reinforced resin in any one of Claims 1-3 whose thickness of the said resin diffusion medium is 200-2000 micrometers. The manufacturing method of the fiber reinforced resin in any one of Claims 1-4 with which the groove process was given to the at least single side | surface of the said core material. Carbon fiber reinforced plastic member consisting used fiber-reinforced resin obtained by the production method according to claim 1-5. The carbon fiber reinforced plastic member according to claim 6, which is used as a member for an automobile.

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