JP6609143B2 - Manufacturing method of fiber-reinforced resin molded body and molded body thereof - Google Patents

Description

  The present invention relates to a method for producing a fiber-reinforced resin molded product and a fiber-reinforced resin molded product produced thereby.

  Since the fiber reinforced resin molding is lightweight and excellent in corrosion resistance, it is used for relatively large products such as automobile panels and parts, and housings of various devices. In conventional fiber reinforced RIM (reaction injection molding) molding, the fiber reinforced resin molded product that is the product has the reinforcing fibers dispersed almost uniformly in the matrix resin raw material regardless of the part, and is compounded at a constant mixing ratio. .

  This matrix resin raw material bonds the reinforcing fibers together to exert the strength performance of the fibers, and the matrix resin fills the spaces between the fibers and maintains the shape. In this case, the reinforcing fibers are kneaded with the liquid matrix resin in advance, or the reinforcing fibers are mixed when the matrix resin raw material is injected. In either case, the reinforcing fibers are already mixed with the matrix resin upstream from the resin injection gate into the mold. This is due to the fact that the fibers are almost uniformly distributed in the resulting product.

  Also known is a method in which a mat, knitted fabric, or a combination thereof is preformed as another reinforcing fiber, set in advance in a mold cavity, and then clamped, and a matrix resin raw material is injected. ing.

  In such prior art, the following Patent Document 1 discloses that a fiber reinforcing material is placed in a mold cavity of a mold composed of an upper mold and a lower mold and clamped, and then a liquid matrix is placed in the mold cavity. In the method of manufacturing a fiber reinforced resin molded body in which a resin raw material is injected, cured, and then the mold is opened and the molded body is taken out. On the surface of the molded body, voids, wrinkles, blisters, cracks, pinholes, fiber patterns, etc. A technique aimed at obtaining a fiber-reinforced resin molded article having no defects and excellent surface smoothness has been proposed.

  That is, in the technique of Patent Document 1, a liquid coating resin is introduced into the mold cavity from the injection port provided in the upper mold during or after the liquid matrix resin raw material injected into the mold cavity is cured. The raw material is injected to form a coating layer made of a resin material for coating on the surface of the fiber reinforced resin molded product. After the resin material for matrix and the coating layer are cured, the mold is opened and the molded product is opened. It is taken out to obtain a fiber reinforced resin molded product.

JP-A-7-214729

  In the above prior art, generally, the performance of the fiber is added by mixing the reinforcing fiber into the matrix resin material, and the strength and rigidity of the resin molded body are improved. However, since the specific gravity of the reinforcing fibers is larger than that of the matrix resin, the strength and rigidity of the product are increased, but there is a disadvantage that the product weight is increased.

  Further, the reinforcing fibers collide with each other when the matrix resin raw material is mixed. That is, when the mixed resin material produced here is poured into the mold, and subsequently flowed and filled in the mold cavity, the reinforcing fibers are attached to each other and to the inner wall of the mold cavity. collide.

  Thus, the reinforcing fiber bends and breaks due to the abrupt transformation when filled to conform to the shape of the product. Further, the fiber length of the reinforcing fiber is shorter than that before mixing into the resin, and the reinforcing fiber is deformed. In addition, during flow and filling inside the mold cavity, the fiber distribution and orientation are not stable, and the stability of the product is hindered. In this case, the product shape may be distorted by non-uniform filling of the reinforcing fibers.

  In addition, since the reinforcing fiber is more expensive than the matrix resin, even if the reinforcing fiber is distributed almost uniformly in the product (fiber reinforced resin molded product), the part that does not require strength and rigidity in the structure of the product Since the reinforced fiber is filled up to 1, the cost effectiveness is inferior.

  Furthermore, since the specific gravity of the reinforcing fiber is larger than that of the matrix resin, the weight of the equivalent functional product having the same shape is increased. Moreover, since the matrix resin mixed with the reinforcing fibers has poor fluidity, it is necessary to make the product thicker in order to compensate for this.

  Although the reinforcing fiber collides with the mold during product molding, the reinforcing fiber is aggressive and shortens the mold life. Therefore, a metal material is required for the mold material, so that the mold cost increases, and the features such as the low cost of the mold cost in RIM molding are lost.

  The present invention has been made in view of the above circumstances, and has established a molding method for efficiently arranging reinforcing fibers inside a product in order to eliminate the drawbacks of the above-described conventional techniques, thereby improving the strength and rigidity of the product. The purpose is to realize weight reduction and cost reduction at the same time. That is, the present invention can produce a fiber reinforced resin molded article that does not damage the mold, thus prolongs the mold life, enables molding with a resin mold and a simple mold, reduces mold costs, and reduces the product price. The present invention proposes a method and a fiber-reinforced resin molded product produced thereby.

The invention described in claim 1 of the present application is to open a molding die composed of an upper die and a lower die, and apply a coating resin on the surface of each die cavity to become the outermost skin of the molded body (1). Forming the surface layer (2) ,
Then, the surface portion (2), the fiber-reinforced resin mixed with reinforcing fibers in the matrix resin is applied to form the outer layer portion (3),
In this outer layer part (3), a reinforcing fiber is thrown onto the outer layer part (3) by an electrostatic flocking method to provide an electrostatic flocking part (5),
Further, the mold is clamped and a resin not containing reinforcing fibers is injected into the mold cavity to form the inner layer portion (4). Then , the mold is opened and the molded body (1) is released. It is a manufacturing method of the fiber reinforced resin molding characterized by these.

According to the second aspect of the present invention, in providing the electrostatic flocking portion (5) according to the first aspect of the present invention, the reinforcing fiber is thrown in a direction perpendicular to the surface of the outer layer portion (3). It is a manufacturing method of the fiber reinforced resin molding characterized by providing a flocking part (5) .

  According to the present invention, the outer layer portion is formed by applying the fiber reinforced resin mixed with the reinforcing fiber on the surface layer portion which is the outermost skin of the molded body, and then the mold is clamped to reinforce the reinforcing fiber in the mold cavity. Since the inner layer portion is formed by injecting a resin that does not contain the reinforcing layer, that is, the reinforcing fiber is mixed only in the outer layer portion, and the inner layer portion is formed without the reinforcing fiber, so that weight reduction and cost reduction can be achieved. .

Also, since the inner layer is formed by injecting resin that does not contain reinforcing fibers into the mold cavity, there is no damage to the mold that may have occurred in the past, thus prolonging the mold life and molding with resin molds and simple molds. This makes it possible to reduce mold costs and reduce product prices. Further, when forming the inner layer portion, from the viewpoint of maintaining strength and rigidity, even if a resin containing some reinforcing fibers is injected, the outer layer portion and the surface layer portion are present, so that the mold may be damaged. Absent. In that sense, “injecting a resin that does not contain reinforcing fibers into the mold cavity to form the inner layer portion” of the present invention is based on the size of the molded body and the structure of the mold composed of the upper mold and the lower mold. Therefore, it does not exclude the mixing of reinforcing fibers to the extent that the mold is not damaged.
Further, in the electrostatic flocking portion, the contact surface between the outer layer portion and the inner layer portion is formed so that the resin is impregnated between the reinforcing fibers, and the outer layer portion and the inner layer portion are firmly bonded. This is because the contact surface of the injected resin has an extremely large area, that is, an anchor effect is exhibited. In addition, when the orientation direction of the reinforcing fibers is changed substantially perpendicularly at the contact surface between the outer layer portion and the inner layer portion, the bonding force can be increased without mixing the reinforcing fibers into the resin injected into the inner layer portion, The strength and rigidity of the product can be maintained.

It is a longitudinal cross-sectional view which concerns on the Example of this invention and shows a fiber reinforced resin molding. It is a longitudinal cross-sectional view which concerns on the other Example of this invention, and shows a fiber reinforced resin molding. It is a longitudinal cross-sectional view which concerns on the other Example of this invention, and shows a fiber reinforced resin molding.

  Hereinafter, the present invention will be described based on examples. As shown in FIGS. 1 to 3, a fiber reinforced resin molded body 1 as a manufactured product of the present example includes a surface layer portion 2, an outer layer portion 3, and an inner layer portion 4 from the outside to the inside. In this example, the surface layer portion 2 is formed by applying a resin such as ABS or acrylic resin. The outer layer part 3 is formed by applying to the surface layer part 2 a fiber reinforced resin in which reinforcing fibers are mixed with the same type of resin as that applied to the surface layer part 2, that is, ABS, acrylic resin, etc. The inner layer portion 4 is formed by a reaction injection molding method (RIM) from a resin that does not contain reinforcing fibers. However, the resin used as the matrix is not limited to that described above, and any appropriate resin can be used. Also, since the outer layer part 3 is formed on the surface layer part 2, both matrix resins have good affinity for each other. It is desirable to choose one. In the embodiment shown in FIG. 1, an electrostatic flocking portion 5 is provided between the outer layer portion 3 and the inner layer portion 4.

  As the mold cavity used in the manufacturing method of the present example, a mold that forms a mold cavity by clamping the upper mold and the lower mold is used as in the conventional example. In addition, since this mold is appropriately used, the illustration thereof is omitted.

  Hereinafter, the manufacturing method of this example will be described in sequence. First, the upper mold and the lower mold are opened, and a resin such as ABS or acrylic resin is applied to the surface of the mold cavity in advance. This is the outermost skin of the surface layer of the molded product, and ensures surface quality, paint adhesion, and plating properties.

  Next, a composite material in which reinforcing fibers are mixed using ABS, acrylic resin or the like as a matrix, that is, fiber reinforced resin, is applied on the surface layer portion. Thereby, the outer layer part 3 is formed on the surface layer part 2.

  Carbon fiber, glass fiber, Kevlar fiber, nylon fiber or the like is used as the reinforcing fiber. Here, several layers of fiber reinforced resin may be stacked. At this time, a plurality of layers may be stacked by changing the amount and orientation of the reinforcing fibers.

  The matrix resin is applied by a spray-up method, electrostatic coating, brush coating, or the like. The fiber orientation is controlled by the spraying pressure and direction at the time of coating, the amount of solvent, and the like. Application should be automated to ensure complexity and increase product stability. In general, it is desirable that the fiber is oriented along the mold surface in a portion close to the product surface. By doing in this way, intensity | strength and rigidity can be improved efficiently with respect to the main stress direction of the load which a product receives normally.

  These application | coating consists of a several process or the process hierarchized continuously. In addition, optimization can be performed by changing the type of resin stepwise, changing the resin-to-fiber ratio (including fiber zero) stepwise, or changing the fiber orientation direction stepwise.

  As shown in FIG. 1, it is desirable to provide an electrostatic flocking portion 5 in which the reinforcing fiber direction is oriented perpendicularly to the product plate thickness in the outer layer portion closest to the center portion and in contact with the inner layer portion. This can be achieved by controlling the fiber orientation by electrostatic flocking. An adhesive resin is applied to the matrix resin layer in advance, and then the reinforcing fibers are cast perpendicularly to the application surface. After fixing the reinforcing fibers, the process of the outer layer portion composed of a plurality of layers is completed.

  Thereafter, the upper mold and the lower mold are clamped, and the process proceeds to a reaction injection molding (RIM) process. In this reaction injection molding, a resin such as urethane or urea is injected. That is, only the resin not containing reinforcing fibers is injected to mold the inner layer portion. Here, it is combined with the fiber reinforced matrix resin of the outer layer portion applied in advance.

  In the flocking layer, the contact surfaces of the outer layer portion and the inner layer portion are formed so that the resin is impregnated between the reinforcing fibers, and the outer layer portion and the inner layer portion are firmly bonded. This has an extremely large contact surface with the injected resin, that is, an anchor effect is exhibited. In this way, the contact surface between the outer layer portion and the inner layer portion changes the orientation direction of the reinforcing fibers substantially perpendicularly, thereby increasing the bonding force without mixing the reinforcing fibers into the resin injected into the inner layer portion. Strength and rigidity can be maintained.

  Since the outer layer portion can be made of fiber reinforced resin and the fiber orientation can be controlled to strengthen the bonding between the outer layer portion and the inner layer portion, a foaming agent can be mixed with the inner layer portion injecting resin to make a porous resin. A foamed molded product having a porous structure is lighter in weight and superior in shock absorbing properties, although its strength is inferior to a solid molded product. If the inner / outer layer joint is reinforced by the anchor effect, the strength and rigidity of the product will be mainly borne by the fiber reinforced resin of the outer layer part, and the foaming rate of the inner layer part will be increased to further reduce the weight and cost. realizable. The injection time of the injection resin is controlled so as to maximize the affinity and binding with the matrix resin.

  On the other hand, in consideration of the strength and rigidity of the product, the inner layer portion may be formed by injecting a resin mixed with the minimum necessary reinforcing fibers. In any case, it is combined with the fiber reinforced matrix resin of the outer layer portion. Thus, the fiber-reinforced resin molded body of this example is covered with a matrix resin layer (multiple layers) in which reinforcing fibers are mixed in the outer layer portion (excluding the surface layer) of the molded product, and the inner layer portion includes a minimum amount of reinforcing fibers. It is composed of a resin layer molded by RIM molding, which is a fiber-reinforced resin molded body having a hierarchical structure.

  In the fiber reinforced resin molded body of this example, if the inner layer resin is foamed in the formation of the inner layer portion, a large number of bubbles in the porous resin molded body reduce the amount of resin used, further reducing weight and cost. I can plan. Moreover, desired product strength and rigidity can be obtained by controlling bubble generation.

  Thus, according to the manufacturing method of this example, the advantages of the conventional RIM molding can be maintained as they are, and the molding of complicated shapes and thick molded products can be facilitated. In addition, a resin can quickly penetrate a sudden plate thickness change such as a thin-walled portion to a locally thick-walled portion, and a highly accurate molded product can be easily obtained such as not causing sink marks.

  Further, in the fiber reinforced resin molded body of this example, the outer layer portion of the fiber reinforced RIM molded resin product is reinforced with fibers. Then, the type and orientation of the fiber can be selected, whereby the degree of freedom in design can be increased, for example, the thick part can be enlarged to increase the strength and rigidity.

  Furthermore, since the inner layer portion can be filled with a lightweight resin, the weight can be reduced. Further, since the injected resin can be foamed, further weight reduction and cost reduction can be achieved.

  The present invention is suitable as one that can be realized by integrating products that could not be realized by fiber reinforced hand layup, carbon fiber reinforced products, and thermoplastic resin injection products.

DESCRIPTION OF SYMBOLS 1 Fiber reinforced resin molding 2 Surface layer part 3 Outer layer part 4 Inner layer part 5 Electrostatic flocking part

Claims (2)

Mold is opened the mold composed of upper and lower mold, by applying a resin for coating the surface of each mold cavity to form a surface layer portion serving as the outermost skin of the molded body (1) (2), then, The outer layer part (3) is formed by applying a fiber reinforced resin in which reinforcing fibers are mixed into a matrix resin to the surface layer part (2) , and the reinforcing fiber is applied to the outer layer part (3) by electrostatic flocking. electrostatic flocking portion by anchoring to the outer layer (3) provided (5), and further clamping, after forming the inner layer portion (4) by injecting a resin containing no reinforcing fibers into the mold cavity The method for producing a fiber-reinforced resin molded article, wherein the mold is opened and the molded article (1) is released from the mold. 2. The electrostatic flocking portion (5) is provided by placing the reinforcing fibers in a direction perpendicular to the surface of the outer layer portion (3) when providing the electrostatic flocking portion (5). Of manufacturing a fiber-reinforced resin molded article.

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