JP2014162848A - Carbon fiber-reinforced resin molded part and composite structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress or prevent electrocorrosion generated in a metal component during use in a carbon fiber-reinforced resin molded part used in a contact state with the metal component.SOLUTION: The carbon fiber-reinforced resin molded part is composed in such a manner that carbon fibers and a particulate or oily silicone compound are dispersed and blended ino the matrix resin of the carbon fiber-reinforced molded part. Further, by the integrally combined constitution of the carbon fiber-reinforced resin molded part and a metallic component, a metal-CFRP composite structure in which electrocorrosion caused by electrolysis is prevented is provided.

Description

  The present invention relates to a carbon fiber reinforced resin molded article and a composite structure using it in combination with a metal part. More specifically, the present invention relates to a carbon fiber reinforced resin that does not cause corrosion caused by electrolytic corrosion at a contact interface with a metal component used together when used in the presence of a conductive liquid. The present invention relates to a molded article and a composite structure. The carbon fiber reinforced resin molded article and composite structure of the present invention can be widely used in various general machines, electrical equipment, industrial equipment, automobiles, mobile machines such as aircraft, home appliances, etc., especially in automobile parts. It can be used advantageously.

  As is well known, carbon fiber is light and strong (mechanical properties), has excellent dimensional stability and heat resistance (thermal properties), and has excellent electrical conductivity and electromagnetic shielding properties (electrical properties). The carbon fiber reinforced resin molded product is widely used for the production of a fiber reinforced resin molded product. The carbon fiber reinforced resin or plastic is hereinafter also abbreviated as “CFRP”.

  Further, although the CFRP molded product may be used alone, it is often used in combination with a metal part in order to bring out the advantages of both. For example, a structure in which a steel plate is reinforced with a CFRP plate, such as a bridge, an iron pipe that constitutes a frame for reducing the weight of a stretcher, is replaced with a combined structure of an aluminum pipe and a CFRP pipe, In order to reduce the weight of the fuselage and reduce maintenance, an article using a laminated composite material in which a CFRP layer and a conductive layer (metal foil) are joined via a metal fastener is proposed instead of the aluminum alloy parts that make up the fuselage. Has been. However, in these laminated composite materials and other composite structures, as described below, the occurrence of corrosion in metal parts exists as a major problem.

  Patent Document 1 relates to a stretcher in which a frame is formed from a combined structure of an aluminum pipe and a CFRP pipe. In the case of this stretcher, there is a problem that an electrolytic corrosion reaction (galvanic corrosion) occurs from the bonding surface and the life is shortened. Therefore, a glass fiber reinforced plastic or tetrafluoride is formed at the bonding portion between the aluminum pipe and the CFRP pipe. It has been proposed to interpose an electrically insulating layer from ethylene. However, the presence of such an electrical insulating layer complicates the structure of the coupling structure, increasing the number of manufacturing steps and increasing the manufacturing cost.

  Patent Document 2 relates to an aircraft fuselage using a laminated composite material in which a CFRP layer and a conductive layer (metal foil) are bonded via a metal fastener. In the case of this fuselage, the metal fastener forms a guide path through which lightning current penetrates the laminated composite material and enters the fuselage during lightning strikes, and may cause electrolytic corrosion due to contact with the CFRP. It has been proposed to seal with a cap of an insulator. However, the cap of the insulator cannot be a drastic solution to electric corrosion, and there is a risk of falling off, resulting in an increase in manufacturing cost. In Patent Document 2, in order to improve lightning resistance, the main objective is to improve the adhesion between the CFRP layer and the metal fastener and to improve the static electricity diffusivity. I'm just doing it.

Japanese Patent Laid-Open No. 11-123765 JP 2012-6528 A

  Accordingly, it is an object of the present invention to provide various types of CFRP molded products used in contact with metal parts, and the galvanic corrosion generated in the corresponding metal parts during the use of the CFRP molded articles and the resulting local corrosion of the metal parts. It is to suppress or prevent corrosion.

  Another object of the present invention is to provide a CFRP molded product capable of preventing electric corrosion and corrosion of metal parts, a composite structure of such CFRP molded product and metal parts, and a method for producing these articles.

  These and other objects of the present invention will be readily understood from the following detailed description.

  As a result of earnest research to find out the cause of electrolytic corrosion occurring in metal parts used in combination with CFRP molded products during use of carbon fiber reinforced resin molded products (CFRP molded products), the present inventors Conductive liquids present at or near the contact interface of metal parts or applied at or near such contact interface (water, salt water, etc .; may be droplets, moisture, moisture, rainwater, etc .; In the present invention, the inventors have obtained the knowledge that such liquids are collectively referred to as “electrolyte”) and cause a bad influence (electron transfer) on the surface of the metal part, and the present invention has been completed. That is, the present inventor imparts water repellency to the surface of the CFRP molded product by adding a predetermined amount of a silicone compound to the matrix resin of the CFRP molded product, and reduces the contact area between the CFRP molded product and the electrolytic solution. Thus, it has been found that the flow of electrons toward the opposing metal parts can be suppressed, and that the electric corrosion resistance can be improved by finally preventing electric corrosion.

  The present invention, in one aspect, is a CFRP molded product used in contact with a metal part, wherein carbon fiber and a particulate or oily silicone compound are dispersed in a matrix resin of the CFRP molded product. The CFRP molded product is characterized by being made.

  In another aspect of the present invention, a metal-characterized in that the CFRP molded product according to the present invention and a metal part arranged in contact with the CFRP molded product are combined and integrated. Located in CFRP composite structure. When integrating a CFRP molded product and a metal part, depending on the manufacturing method used and other factors, a coupling means such as an adhesive, a bolt and a nut, and other fastening means are provided between them. It may be interposed, or it may not be interposed.

  According to the present invention, as will be understood from the following detailed description, in an integrated composite structure of a CFRP molded product and a metal part, it is light and strong (mechanical characteristics), and has excellent dimensional stability and heat resistance. Integrated composite in the presence of conductive liquid (electrolyte) while taking advantage of CFRP characteristics such as possessing (thermal characteristics), excellent electrical conductivity and electromagnetic shielding characteristics (electrical characteristics) Since it is possible to prevent or suppress the electrical corrosion of metal parts of the structure and the corrosion caused thereby, the present invention can be widely applied to various general machines, electrical equipment, industrial equipment, automobiles, mobile machines such as airplanes, home appliances, etc. It can be used, and particularly in automobile parts, it can be advantageously used as a high-strength member that does not cause electrolytic corrosion and corrosion of metal parts. In addition, due to its superior characteristics, the range of use of the integrated composite structure can be made wider than the conventional range, and the combination examples of CFRP molded products and metal parts can be made more diverse. .

  In addition, according to the present invention, it is not necessary to provide an insulating layer between the CFRP molded product and the metal part or to further complicate the laminated structure. An increase in cost can be prevented.

  Furthermore, according to the present invention, by adding a predetermined amount of a silicone compound to the matrix resin of the CFRP molded product, the CFRP molded product itself can have a function of suppressing electrolytic corrosion. Here, instead of adding a silicone compound, a method of applying a silicone coating to the surface of a CFRP molded product is considered as another option. The manufacturing cost increases due to an increase in cycle time due to the above, and when an engineering plastic is used as a matrix resin, it becomes difficult to ensure the adhesion between the surface of the CFRP molded product and the silicone coating material. The present invention is advantageous in that the desired effect can be achieved simply by adding a silicone compound before molding CFRP.

It is sectional drawing which showed typically the structure of the carbon fiber reinforced resin molded product by this invention. It is sectional drawing which showed typically one form of the composite structure by this invention. It is the perspective view which showed typically another form of the composite structure by this invention. It is the perspective view which showed typically another form of the composite structure by this invention. It is the schematic diagram explaining the mechanism of generation | occurrence | production of the electrolytic corrosion in the contact interface of a metal component and a carbon fiber reinforced resin molded product. It is a top view (surface and back surface) of the specimen of the metal component used for evaluation of electric corrosion resistance. It is sectional drawing which showed typically the testing apparatus used for evaluation of electric corrosion resistance. It is the graph which plotted the evaluation result of electric corrosion resistance.

  Next, preferred embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The carbon fiber reinforced resin (CFRP) molded product and the metal-CFRP composite structure of the present invention are not limited to those shown in the drawings, and various modifications and improvements can be made within the scope of the present invention. it can.

  The present invention resides in a CFRP molded product used in contact with a metal part. Here, the “contact state” means that the metal part and the CFRP molded product are in contact with each other in at least a part of the region. For example, when an injection molding method or the like is used, the metal part and the CFRP molded product can be firmly bonded by injection bonding without interposing a bonding means such as an adhesive between them. In carrying out the present invention, if necessary, a coupling means such as an adhesive may be interposed between the metal part and the CFRP molded product, or other fastening means may be used. Examples of suitable fastening means include a combination of bolts and nuts.

  The CFRP molded product of the present invention is characterized in that carbon fiber (CF) and particulate or oily silicone compound are dispersed and blended in a matrix resin of the CFRP molded product. FIG. 1 schematically shows this feature. From this figure, a CFRP molded product 1 according to the present invention includes a matrix resin 2, a carbon fiber 3 dispersed in the matrix resin 2, and a silicone compound (here Then, it turns out that it is comprised from the particulate silicone rubber) 4. The dispersion form of the carbon fiber and the silicone compound in the matrix resin is not particularly limited as long as the desired effect is achieved, and can be obtained by performing a dispersion treatment according to a conventional method.

  The CFRP molded product is mainly composed of a matrix resin. Although the matrix resin includes any resin, preferred resins are thermoplastic resins commonly used in the manufacture of CFRP molded articles. Since CFRP pellets using a thermoplastic resin as a matrix resin can be injection molded, a CFRP molded product having a high degree of shape freedom and an arbitrary shape can be obtained. Examples of preferable thermoplastic resins include general-purpose thermoplastic resins such as vinyl chloride resin, polypropylene resin, and polyethylene resin, and so-called engineering plastics such as polyamide resin, polyacetal resin, and polycarbonate resin.

  The carbon fiber (CF) dispersed in the matrix resin can include any carbon fiber as in the matrix resin. That is, as the carbon fiber, any of a PAN-based carbon fiber using PAN precursor (polyacrylonitrile fiber) as a raw material, a pitch-based carbon fiber using coal tar as a raw material, and a rayon-based carbon fiber may be used. Different types of carbon fibers may be used in combination. Moreover, the carbon fiber to be used is not limited to the type, and the form is not limited. That is, the carbon fiber may be either a short fiber or a long fiber, and when the raw yarn is a short fiber, the form of the staple may be mentioned, and when the raw yarn is a long fiber, the form of the filament may be mentioned. it can. Further, in the practice of the present invention, carbon fibers are not caught in these forms, and are processed into forms such as chopped yarns, felts, mats, etc., as necessary, through steps such as cutting, crushing, and spinning. May be.

  Carbon fibers can be blended in a CFRP molded product in a wide range depending on the desired effect. The blending amount of CF is usually preferably in the range of about 10 to 70% by volume, more preferably in the range of about 10 to 50% by volume, based on the total amount of the CFRP molded product. Usually, as the blending amount of CF increases, improvement in physical properties can be achieved in the obtained CFRP molded product. However, as a result of poor fiber dispersibility, it tends to be difficult to mold. Generally, when a CFRP molded product is manufactured by injection molding, a CFRP blended amount of about 10 to 30% by volume can be used in many cases.

  The silicone compound dispersed in the matrix resin can include any silicone compound as long as it can be dispersed in the form of particles or oil in the CFRP molded article, similarly to the matrix resin and carbon fiber. As is well known, a silicone compound is an oligomer or polymer produced by hydrolyzing various silanes including dichlorodimethylsilane and then dehydrating and condensing, and commercially available products can be used as required. . Examples of suitable silicone compounds include particulate silicone rubber (silicone powder) and liquid silicone oil.

  The silicone compound can be blended in the CFRP molded product in a relatively small amount depending on the desired effect. The compounding amount of the silicone compound is usually preferably in the range of about 1 to 10% by weight, more preferably in the range of about 2 to 6% by weight, and most preferably about 2 to 4% by weight, based on the total amount of the CFRP molded product. % Range. As the amount of the silicone compound is increased, it is expected that the improvement of the electric corrosion resistance of the metal part in the obtained CFRP molded article can be achieved, but the physical properties of the obtained molded article will be lowered.

  The CFRP molded product of the present invention may be improved in physical properties by blending optional additives other than carbon fiber and silicone compound, if necessary. Examples of suitable additives include viscosity modifiers, antioxidants, light stabilizers, colorants, flame retardants, modifiers, fungicides, and antibacterial agents.

  The CFRP molded product of the present invention can be produced by arbitrarily using various methods conventionally used for the production of CFRP molded products, or by arbitrarily changing the method. For example, a matrix fiber pellet (CFRP pellet) containing an appropriate amount of carbon fiber is carefully mixed with an appropriate amount of a silicone compound (specifically, silicone powder or silicone oil) with an appropriate mixing device such as a kneader or a mixer. After kneading to uniformly disperse the silicone compound in the kneaded product, the obtained kneaded product is molded, for example, with an injection molding machine, etc., so that a desired CFRP molded product can be manufactured easily and at low cost. Can do.

  The present invention also provides a metal-CFRP composite structure in which the carbon fiber reinforced resin molded product (CFRP molded product) of the present invention and a metal part placed in contact with the CFRP molded product are combined and integrated. It is in. In this metal-CFRP composite structure, the CFRP molded product and the metal part can be combined, contacted, and integrated in an arbitrary form. In general, it is preferable that a metal component is disposed in a contact state at least at one of the surface, the convex portion, the concave portion, or the penetrating portion of the CFRP molded product. Here, as described above, the “contact state” only needs to ensure that the metal part and the CFRP molded product are sufficiently in contact with each other, and a coupling means such as an adhesive is interposed between the two. They may or may not be used, and may be fastened by other fastening means such as a combination of bolts and nuts.

  Further, in the metal-CFRP composite structure, the CFRP molded product and the metal part can have the same or different shapes, and can have arbitrary shapes. For example, the CFRP molded product and the metal part may adopt a structure in which the flat surfaces or side surfaces of the CFRP molded plate and the metal plate are abutted, a structure in which a metal bolt is attached to the CFRP molded disc, or a CFRP molded disc You may employ | adopt the structure which fitted the annular metal insert in the through-hole of this. The metal-CFRP composite structure can be easily manufactured by joining and integrating the CFRP molded product and the metal part using a conventional technique such as an injection joining method.

  The metal part can be formed of any metal material as long as the effect of improving the corrosion resistance of the present invention is obtained. That is, a suitable metal material is a metal material that can be subjected to electrolytic corrosion when used by being bonded to a CFRP molded product, and specifically, a metal material having a difference in natural potential from the CFRP molded product. . Suitable metal materials include, but are not limited to, iron, stainless steel, aluminum, zinc or alloys thereof such as duralumin. Note that the metal part may be a single part by combining two or more metal members made of the same or different types of metal materials as necessary.

  In the metal-CFRP composite structure of the present invention, it is possible to achieve a marked improvement in the resistance to electric corrosion at a position in the vicinity of the contact interface of the metal part that comes into contact with the CFRP molded product. As described above, this excellent effect can be achieved by eliminating the cause of the adverse effect (electron movement) of the electrolyte solution on the surface of the metal part. By understanding the occurrence of electrolytic corrosion (corrosion) in the metal parts described below, it will be easy to understand the reason why the present invention achieves improved electrolytic corrosion resistance.

  FIG. 5 schematically shows the mechanism of the occurrence of electrolytic corrosion at the contact interface between the metal part and the carbon fiber reinforced resin molded product. The illustrated metal-CFRP composite structure is formed by abutting and joining the side surfaces of the CFRP plate 1 and the aluminum plate 5 together. This composite structure is immersed in water, which is a kind of electrolytic solution in the present invention, and the behavior near the contact interface (CI) between the CFRP plate 1 and the aluminum plate 5 is observed.

As for the natural potential of the CFRP plate 1 and the aluminum plate 5 (E), as shown, with a single potential of CFRP plate 1 _{P CFPR,} since a single potential of the aluminum plate 5 is a _{P Al,} both There is a clear difference in the natural potential. Further, a mixed potential (P _mix ) is generated near the contact interface between the CFRP plate 1 and the aluminum plate 5, and the corrosion current CA flows to move electrons, so that electrolytic corrosion occurs in the corrosion region C of the aluminum plate 5, As illustrated, corrosion of the aluminum plate 5 proceeds. Such corrosion occurs because the amount of movement of electrons from the CFRP plate 1 into water corresponds to the aluminum corrosion amount of the aluminum plate 5. Although water is shown as the electrolyte in FIG. 5, the same electrolytic corrosion occurs when a conductive liquid such as an aqueous solution of sodium chloride, salt water, rain water, or condensation adheres to the aluminum plate 5 instead of water. The occurrence can be observed.

  In contrast, in the present invention, since a silicone compound is blended inside the CFRP plate, electrolytic corrosion can be prevented by utilizing the developed water repellency. That is, the contact area of CFRP / water is reduced by imparting water repellency to the CFRP plate, and as a result of reducing the amount of electron movement, the amount of corrosion of the aluminum plate due to electrolytic corrosion can be reduced. In other words, the action of the electrolyte solution on the surface of the CFRP plate can be suppressed or prevented by the action of the silicone compound, and as a result, the flow of corrosion current (electrons e) is prevented and the corrosion of the aluminum plate is also prevented. can do.

  The metal-CFRP composite structure of the present invention can be produced by joining a CFRP molded product having an arbitrary shape and a metal part at an appropriate site, joining them, and integrating them. 2 to 4 schematically show examples of such metal-CFRP composite structures. A metal-CFRP composite structure 10 in FIG. 2 is obtained by joining the back surface of a metal part 5 to a surface of a flat CFRP molded product 1 through a thin layer of an adhesive 6. The adhesive 6 can be, for example, an epoxy resin. The thin layer of the adhesive 6 can be omitted depending on the joining means used.

  The metal-CFRP composite structure 10 of FIG. 3 shows a bolt fastening structure in which a metal bolt 11 is attached to a CFRP molded disc 15. By configuring the bolt fastening portion in this way, electrolytic corrosion at the metal bolt / CFRP interface can be prevented. Further, the metal-CFRP composite structure 10 of FIG. 4 shows a metal insert structure for bolt fastening in which an annular metal insert 21 is fitted in a central through hole of an annular CFRP molded product 25. By comprising in this way, the electrolytic corrosion in a metal insert / CFRP interface can be prevented.

  As can be understood from the above, the metal-CFRP composite structure of the present invention is basically in a liquid having conductivity such as water or salt water, or such liquid may adhere to metal parts. However, even in such an environment containing liquid, moisture or moisture, condensation, rainwater, etc. It can be effectively prevented.

(Evaluation of electric corrosion resistance)
In this example, the “coupling current measurement method” established as an evaluation means was employed for evaluating the corrosion resistance of metal parts in a metal-CFRP composite structure. In the coupling current measurement method, the amount of electrons measured as a coupling current amount (coupling current amount) between an electrode (specimen) corresponding to a metal part and an electrode (specimen) corresponding to a CFRP molded product is The evaluation means is based on dealing with the amount of electrolytic corrosion (corrosion amount) that progresses in the metal part that is the counterpart metal.

(Production of electrode specimen)
An electrode specimen having the same shape and size was prepared for each of the aluminum metal part and the CFRP molded product (the matrix resin was a polyamide resin). FIG. 6 schematically shows the front surface (A) and the back surface (B) of the aluminum electrode 5 which is one of the electrodes. As shown in the figure, the aluminum electrode 5 has a width of 10 mm, a length of 20 mm, and a thickness t of 4 mm. After covering the front and back surfaces of the aluminum electrode 5 with the masking tape 7, a part of the test surface (6 mm × 6 mm) was exposed to form the test surface 5a. The obtained aluminum electrode specimen 5 was used in subsequent evaluation tests.

Although not shown, the CFRP electrode specimen was also produced in the same shape and size. However, the CFRP electrode specimen was examined in the following 3 in order to consider the results when the silicone compound (trade name “Shin-Etsu Silicone (X-22-8171)”, manufactured by Shin-Etsu Chemical Co., Ltd.) was blended in different amounts. Various types of specimens were prepared.
Specimen A: Silicone compound 0% by weight
Specimen B: 2% by weight of silicone compound
Specimen C: Silicone compound 4% by weight

(Evaluation test)
An evaluation test was performed using the test apparatus shown in FIG. A 5% sodium chloride (NaCl) aqueous solution 8 was accommodated in the treatment tank. Subsequently, the aluminum electrode specimen 5 and the CFRP electrode specimen (A, B, or C) 1 prepared earlier were arranged with their test surfaces facing each other. The distance between the two facing specimens was 10 mm. In addition, the aluminum electrode specimen 5 and the CFRP electrode specimen 1 were connected to a DC power source (not shown), and an ammeter 9 was disposed in the middle of the connection. The coupling current value after a constant current (40 mA) was passed between the two electrode specimens for 24 hours was measured.

(Measurement results and evaluation)
As a result of the measurement, the coupling current value obtained was about 12 μA for the CFRP electrode specimen A, about 9.5 μA for the CFRP electrode specimen B, and the CFRP electrode specimen, as plotted in FIG. In the case of C, it was about 5 μA.

  From these measurement results, it can be seen that the coupling current value decreases as the silicone compound in the CFRP molded product increases. That is, a decrease in the coupling current value means that the amount of aluminum ionized by electrolytic corrosion is reduced. Therefore, normally, by adding a silicone compound in an amount of about 1% by weight or more, the electric resistance can be increased. It turns out that food property can be improved.

  The CFRP molded product and the metal-CFRP composite structure of the present invention are excellent in mechanical properties, thermal properties, electrical properties, etc., and in the presence of a conductive liquid, the electrolytic corrosion of metal parts and thereby Since corrosion can be prevented or suppressed, it can be widely used in various general machinery, electrical equipment, industrial equipment, automobiles, mobile machines such as aircraft, home appliances, etc. It can be advantageously used as a high-strength member that does not cause electrolytic corrosion and corrosion.

DESCRIPTION OF SYMBOLS 1 Carbon fiber reinforced resin molding 2 Matrix resin 3 Carbon fiber 4 Silicone compound 5 Metal component 6 Adhesive layer 7 Masking material 8 Electrolyte 10 Composite structure 11 Metal bolt 15 CFRP component 21 Metal insert 25 CFRP component

Claims (8)

  A carbon fiber reinforced resin molded product used in contact with a metal part, wherein carbon fiber and particulate or oily silicone compound are dispersed and blended in a matrix resin of the resin molded product. Carbon fiber reinforced resin molded product.   The carbon fiber reinforced resin molded product according to claim 1, wherein the carbon fiber is blended in an amount of 10 to 70% by volume based on the total amount of the resin molded product.   The carbon fiber reinforced resin molded product according to claim 1 or 2, wherein the silicone compound is blended in an amount of 1 to 10% by weight based on the total amount of the resin molded product.   2. The carbon fiber reinforced resin molded article according to claim 1, wherein the metal component is an article manufactured from a metal material that can be subjected to electrolytic corrosion when used while being bonded to the carbon fiber reinforced resin molded article.   The carbon fiber reinforced resin molded product according to claim 4, wherein the metal material is selected from iron, stainless steel, aluminum, zinc, or an alloy thereof.   Carbon fiber reinforcement according to any one of claims 1 to 5, used in a liquid having electrical conductivity, in the vicinity of such a liquid or in an atmosphere containing such a liquid, moisture or moisture. Resin molded product.   A composite structure in which the carbon fiber reinforced resin molded product according to claim 1 and a metal part arranged in contact with the resin molded product are combined and integrated.   The composite structure according to claim 7, wherein the metal component is arranged in a contact state at least one portion of a surface, a convex portion, a concave portion, or a penetrating portion of the resin molded product.

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