JP3686527B2 - Metal coating method of carbon fiber reinforced plastic - Google Patents

Description

【００２３】
この結果、第１の参考例は、銅めっき研磨面、硬質クロムめっき研磨面ともに、試験片の全数について良好な密着性を発揮した。これに対して比較例は全数剥がれを生じて不良であった。
【００２４】
（第２の参考例）
第２の参考例は、第１の参考例が３０μｍ長の金属粒子を用いたのに対し、径が約１０〜２００μｍの範囲の金属粒子を用いたものである。
樹脂を含浸した炭素繊維のプリプレグを積層し、硬化してＣＦＲＰ円筒２１を製作する。このＣＦＲＰ円筒２１の外表面２２を＃４００相当の耐水研磨紙を用いて研磨する。以上、図２（ａ）参照。
【００２５】
トルエン等の溶剤で洗浄後、塗布する塗料２５は径が約１０〜２００μｍの球状の銅粒子２３を加熱硬化型エポキシ樹脂２４（米国ＤＥＸＴＥＲ Ｃｏｒｐ製のＥＡ−９３９４）中に６０〜９０重量％で混和させ、トルエン溶剤を加えたものとする。この塗料２５をエアースプレーガンを用いて約２００μｍ塗布する。その後、乾燥させ、メーカーの加熱条件により１２０℃で硬化する。ここで用いた銅粒子２３は福田金属箔粉工業（株）製のもので商品名はＣｕ−Ａｔ−１００である。以上、図２（ｂ）参照。
【００２６】
次に乾燥硬化させたＣＦＲＰ円筒２１の塗布面を回転砥石により研磨する。この塗布面の研磨により金属粒子である銅粒子２３が切断され、その断面が露出した研磨面Ｓを形成する。そして研磨後の塗布層の厚さＴ２が８０〜２００μｍ程度になるようにする。以上、図２（ｃ）参照。
【００２７】
洗浄後、この銅粒子２３の露出した研磨面上に第１の参考例と同様の硫酸銅電気めっきを実施する（２０℃で４時間）。銅めっき層２６を約９０μｍ被覆した後、回転砥石により研磨してめっき層ｔ２を７０μｍ以上とする。以上、図２（ｄ）参照。
【００２８】
さらに洗浄した後、この研磨した銅めっき層２６の上に、一般に行われているサージェント浴の硬質クロムめっきを５０℃で１０時間以上行い、約１３０μｍの硬質クロムめっき層２７を被覆する。被覆した硬質クロムめっき層２７を研磨し、硬質クロムめっき層２７の厚さが約１００μｍ以上になるように仕上げる。以上、図２（ｅ）参照。
【００２９】
このようにして得られた第２の参考例について、その密着性を前記第１の参考例と同様のテストを実施した。このテスト結果を表２に示す。ここで、第２の参考例を比較するための「比較例」は、銅粒子２３を加えず、エポキシ樹脂（前記ＥＡ−９３９４）にトルエン溶剤を加えたもので、その他の塗装条件は同一である。また第２の参考例の試料に関するデータは、研磨後の塗装厚さが１５０μｍ、研磨後の銅めっき厚さが７０μｍ、研磨後の硬質クロムめっきが１００μｍである。

【００３０】
この結果、第２の参考例でも、銅めっき研磨面、硬質クロムめっき研磨面ともに、試験片の全数について良好な密着性を発揮した。これに対して比較例は全数剥がれを生じて不良であった。
【００３１】
これら２つの参考例の結果から、ＣＦＲＰ円筒の外表面に銅めっきおよび硬質クロムめっき層が形成しやすく、粘着テープによっても、また研磨中の研磨砥石によっても剥がれを生じない、密着強度の大きい金属めっき被膜が得られることが裏付けられた。
【００３２】
以上述べた第１、第２の参考例においては、合成樹脂の中に予め金属粒子を混和させて塗料化したものをエアースプレーにより塗装するものであった。この方法は部品の外表面を塗装するには適しているが、小径の円筒内面などの狭隘部に対しては問題がある。すなわち、めっきによる金属被覆は下地となる金属粒子を均一に連続して分散させることが基本であり、そのためにはスプレーガンの塗布面に対する角度や距離を一定にする必要がある。このような点からスプレーガンは塗装面から少なくとも１０ｃｍ程度離す必要があり、１０ｃｍより径が小さい例えば円筒の内表面にはスプレー塗装をすることができない。このため本発明はさらにエアースプレーにはよらない、言い換えれば径の小さい部位にも適用できる金属被覆方法を提供するもので、以下本発明の実施の形態を説明する。
【００３３】
ここで実施の形態の説明に入る前に、その概要を述べることとする。ＣＦＲＰ円筒の内表面を研磨して粗な面を形成し、洗浄後この粗な面に加熱硬化型エポキシ樹脂を内表面全体に塗布する。塗布する方法は、一般に行われている流し塗りや浸漬塗りなどによる。エポキシ樹脂の塗布面に金属粒子をふりかけ、金属粒子を含浸させる。その後、加熱して樹脂を硬化する。次にこの塗布面を手作業もしくは機械装置を用いた研磨により研磨し、金属粒子を切断しその断面を露出させる。そして洗浄後、この金属粒子が露出した研磨面に、一般に行われている化学めっき又は電気めっきを施すことによって金属を被覆するものである。
【００３４】
このプロセスにより、銅めっき（金属）が研磨された面に露出している銅粒子の切断断面に析出する。続いて各々の銅粒子上の銅めっきが時間と共に厚く広く成長し、露出している銅粒子間がはしかけとなって内表面全体が銅めっきで結合する。したがって大きい銅粒子を介してエポキシ樹脂と銅めっきとが付着するので、密着力の優れた金属めっき被膜がＣＦＲＰ円筒の内表面に形成される。
【００３５】
（実施の形態）
実施の形態を図３に基づいて述べる。樹脂を含浸した炭素繊維のプリプレグシートを積層し、硬化してＣＦＲＰ円筒３１を製作する。このＣＦＲＰ円筒３１の内表面３２を＃４００相当の研磨紙で研磨する。以上、図３（ａ）参照。
【００３６】
研磨した内表面３２をトルエン等の溶剤で洗浄後、加熱硬化型のエポキシ樹脂３４（一例として、米国ＤＥＸＴＥＲ Ｃｏｒｐ製のＥＡ−９３９４）を塗布する。塗布する方法は、塗装において一般に行われている流し塗り或いは浸漬塗りによる。以上、図３（ｂ）参照。
【００３７】
次いでエポキシ樹脂３４が硬化しない間に銅粒子３３をエポキシ樹脂３４中に含浸させる。具体的には、ＣＦＲＰ円筒３１の一端を高くして約６０度傾け保持し、上から銅粒子３３（ここで銅粒子３３は第２の参考例で用いたものと同じ、福田金属箔粉工業（株）製の商品名：Ｃｕ−Ａｔ−１００である）をＣＦＲＰ円筒３１の内表面３２全体に沿わせて落下させる。この場合ＣＦＲＰ円筒３１の傾斜は約３０度から８０度の範囲が良い。傾斜角度が小さいと銅粒子３３が滑らかにエポキシ樹脂３４の表面を覆っていかず、傾斜角度が大きいと銅粒子３３のエポキシ樹脂３４への含浸が不均一になり易いため、この範囲が好ましい。ＣＦＲＰ円筒３１の上方から落下させた銅粒子３３がＣＦＲＰ円筒３１の下部まで行き渡ったら、ＣＦＲＰ円筒３１を回して同様に銅粒子３３を落下させ、順次これを繰返してＣＦＲＰ円筒３１の内表面３２の全周を銅粒子３３で覆う。また銅粒子３３を落下させる際、ＣＦＲＰ円筒３１の中に穴、溝あるいは網付きの治具を用いてもよい。銅粒子３３が含浸されつくすと、樹脂が不足状態になるので、余分な銅粒子３３は樹脂には付着されなくなる。この段階まで銅粒子３３をふりかけたら、ＣＦＲＰ円筒３１を垂直に立てるなどして過剰の銅粒子３３を除去する。以上、図３（ｃ）参照。
【００３８】
そしてＣＦＲＰ円筒３１を加熱炉に入れ、エポキシ樹脂３４：ＥＡ−９３９４の硬化条件にしたがって１２０℃で１時間加熱硬化する。硬化後回転砥石で研磨して平滑面とする。この研磨により金属粒子である銅粒子３３が切断されその断面が露出した研磨面Ｓを形成する。研磨後の銅粒子３３を含んだエポキシ樹脂層の厚さＴ３は次の電気めっきの導電化のために、少なくとも８０μｍ程度必要である。以上、図３（ｄ）参照。
【００３９】
次いで洗浄後、一般に行われている硫酸銅めっきを施す。銅めっき層３６を１００μｍ以上付加した後、回転砥石で研磨して銅めっき層３６の厚さｔ３を約８０μｍとする。以上、図３（ｅ）参照。
【００４０】
さらに洗浄後、研削した銅めっき層３６の上に、一般に行われているサージェント浴の硬質クロムめっきを行い、約１３０μｍの硬質クロムめっき層３７を付加し、回転砥石で研磨して約１００μｍの硬質クロムめっき層３７になるように仕上げる。以上、図３（ｆ）参照。
【００４１】
こうして得られた実施の形態について、その密着性を前記第１の参考例と同様のテストを実施した。このテスト結果を表３に示す。

【００４２】
この結果、本実施の形態でも、銅めっき研磨面、硬質クロムめっき研磨面ともに、試験片の全数について良好な密着性を発揮した。
【００４３】
【発明の効果】
以上述べたように、この発明は、寸法的に小さいＣＦＲＰ材の内表面に対して合成樹脂を流し塗りや浸漬塗りなど一般に行われている塗布方法により塗布し、塗布面に金属粒子をふりかけて金属粒子を含浸させる。乾燥硬化した後、研磨して前記金属粒子を切断してその断面を露出させ、更に一般に行われている化学めっき又は電気めっき方法により、ＣＦＲＰ材に金属を被覆することができるので、特殊な器具、複雑な装置などを用いず、低コストである。
【００４４】
化学めっき又は電気めっきのめっき（金属）が研磨された面に露出している金属粒子の切断断面に付着し、合成樹脂中に混和又は含浸された金属粒子を介して合成樹脂とめっきとが付着するので、密着力の優れた金属めっき被膜が生成される。
【００４５】
また、プラスチック部品の上に金属を混和又は含浸した樹脂層を形成し、その上に金属を被覆するから、炭素繊維強化プラスチック材料に限らず一般のプラスチック材料、その他樹脂層が形成されていれば、適用可能であり応用範囲が広い。また、樹脂を塗布するから部品は凹凸のある形状でも良く、部品選択に制約を受けず、適用範囲が広い。
【図面の簡単な説明】
【図１】 この発明に係る第１の参考例を示す図である。
【図２】 この発明に係る第２の参考例を示す図である。
【図３】この発明の実施の形態を示す図である。
【符号の説明】
１１、２１、３１ ＣＦＲＰ円筒
１２、２２ ＣＦＲＰ円筒の外表面
３２ ＣＦＲＰ円筒の内表面
１３、２３、３３ 銅粒子（金属粒子）
１４、２４、３４ 合成樹脂、エポキシ樹脂
１５、２５ 塗料
１６、２６、３６ 銅めっき層（電気めっき層）
１７、２７、３７ 硬質クロムめっき層
Ｓ 研磨面
Ｔ１、Ｔ２、Ｔ３ 研磨後の塗布層（エポキシ樹脂）の厚さ[0001]
BACKGROUND OF THE INVENTION
This invention provides a carbon fiber reinforced plastic, about the particular metallization how to obtain the adhesion and wear resistance superior plating.
[0002]
[Prior art]
So-called engineering plastics are lighter than metals and have excellent moldability and mass productivity, such as injection molding with molds, and are excellent in corrosion resistance, self-lubrication, and decorative properties, but heat resistance, weather resistance, especially mechanical strength. There were insufficient points in terms of As a material that covers defects while retaining the characteristics of this plastic, there is a composite material in which various fibers are used as a reinforcing material and a thermosetting resin as a matrix, that is, a fiber reinforced plastic (FRP). Among them, carbon fiber reinforced plastic (CFRP) is widely spread and used in various industries from aircraft parts, machinery and electronics industries to sporting goods.
[0003]
However, CFRP material cannot be used as it is in parts that require wear resistance and hardness, so metal is coated by plating or thermal spraying, and the function is not inferior to plated metal die-cast parts. And show its strengths. In this case, an ABS resin (consisting of three components of acrylonitrile, butadiene and styrene) is generally used as a plastic as a base material. This is because a metal plating film having sufficient adhesion can be obtained only by chemical etching. When the ABS material is immersed in an oxidizing etching solution, the butadiene rubber component is selectively dissolved, and innumerable minute irregularities are formed on the surface, and the plating bites into the minute irregularities. It is considered.
[0004]
Here, the epoxy resin, which is excellent in mechanical properties and thermal properties as a reinforced plastic, has a problem in the adhesion of metal plating because there is no portion that is eluted by the etching solution. Thus, various attempts have been made to improve the adhesion strength of ordinary plastics and fiber reinforced plastics.
[0005]
For example, what is found in Japanese Patent Application Laid-Open No. 60-15142 is a structure in which a metal fiber layer is formed by winding a metal fiber around a fiber reinforced plastic cylinder, and a metal spray coating is provided thereon. Technology to obtain a cylinder with a sprayed metal film that penetrates and fuses not only to the metal fiber layer but also to the integrated fiber reinforced plastic to improve adhesion, and has excellent peeling resistance and good sliding wear. It is disclosed.
[0006]
Japanese Patent Application Laid-Open No. 61-12872 discloses that a metal powder is dispersed on the surface of a reinforced plastic, the surface of the cured fiber reinforced plastic is etched, the metal powder is eluted, and chemical plating is performed thereon. A metal plating method with high adhesion is shown.
[0007]
Furthermore, Japanese Patent Application Laid-Open No. 62-133060 discloses a method of applying a synthetic resin solution to a plastic molded article and the like, and coating the resulting coating or film by low-temperature spraying before the resulting coating is dried and solidified. Yes.
[0008]
[Problems to be solved by the invention]
However, the one disclosed in Japanese Patent Application Laid-Open No. 60-15142 is limited to a shape suitable for winding since a metal fiber is wound around a fiber-reinforced plastic cylinder.
[0009]
JP-A-61-12872 is a process in which a metal powder is dispersed and applied to the surface of a fiber reinforced plastic, and then the fiber reinforced plastic is cured. In this case, the metal layer is removed after curing. It is difficult to repair. Moreover, since the size of the metal powder is 10 μm or less, it is difficult to obtain a high anchor effect.
[0010]
On the other hand, in Japanese Patent Application Laid-Open No. Sho 62-133060, the low temperature spraying conditions are such that the metal is arc-melted at about 1350 ° C. and at the same time an inert gas such as nitrogen is injected at a compression air pressure of about 5-10 kg / cm ^2. Therefore, the control and the device for it become complicated and heavy equipment. Furthermore, although it is said that a sprayed coating having a finer uneven surface can be obtained as compared with other thermal spraying methods, the working efficiency is not good compared with chemical plating or electroplating in which the whole is plated at once. Moreover, the adaptation is insufficient for the inner surface where the spray nozzle is difficult to reach.
[0011]
As described above, various methods have been developed for coating the metal on the surface of the fiber reinforced plastic. However, there is a possibility that the parts to be coated are limited to a simple shape or the reinforcing fiber of the FRP may be damaged. There were many problems such as being complicated or complicated control and apparatus therefor. In order to solve these problems, the present invention has a cylindrical outer surface by a simple and low-cost method using a general coating means and a conventional plating means. The purpose is to obtain a metal plating film with excellent adhesion and wear resistance that can be easily applied to narrow parts such as cylindrical inner surfaces where spray coating, which is a general painting means, is difficult to perform And
[0012]
[Means for Solving the Problems]
In the first aspect of the invention, the inner surface of the carbon fiber reinforced plastic is polished to form a rough surface, and after washing, an epoxy resin is applied to the rough surface, and the metal particles are dispersed while the epoxy resin is not cured. The epoxy resin is dried and cured by heating or standing at room temperature, and the epoxy resin that has been dried and cured is polished to form a polished surface that is exposed by cutting the metal particles. After cleaning, the polished surface is chemically plated. Alternatively, electroplating is performed.
[0013]
As a result, the inner surface of the CFRP material having a small size is applied by a commonly applied application method such as flow coating of synthetic resin, and the coated surface is sprinkled with metal particles so that the metal particles are impregnated and polished. Since the metal particles can be cut and exposed and the CFRP material can be coated with a metal by a generally used plating method, a special tool or a complicated apparatus is not used, and the cost is low.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
In describing embodiments of the present invention, first and second cases where hard chromium plating is applied to the outer surface of a carbon fiber reinforced plastic (hereinafter referred to as CFRP) cylinder as a reference example related to the present embodiment . each Figure 1 the reference example of, described with reference to FIG. 2, will be described with reference to FIG. 3 as the present embodiment a case in which hard chrome plating on the inner surface of the CFRP cylinder.
[0015]
First, an overview of the first and second reference examples will be described.
The outer surface of the CFRP cylinder is polished to form a rough surface, and a synthetic resin miscible material in which metal particles are previously mixed is applied to the rough surface. The method of application is by an air spray gun or brush coating, which is generally performed in painting. Thereafter, the CFRP cylinder is dried, and the coated surface is cured by heating or standing at room temperature. Next, the coated surface is polished manually or using a mechanical device, and the metal particles are cut and exposed. Then, the metal surface is coated by performing chemical plating or electroplating generally performed on the polished surface where the cross section of the metal particles is exposed. Of course, cleaning is performed after the polishing step.
[0016]
By this process, chemical plating or electroplating (metal) adheres to the cut cross section of the metal particles exposed on the polished surface. Subsequently, the plating on each metal particle grows thick and wide with time, and the exposed metal particle cross-section is overhanged so that the entire polished surface is covered with the plating. Therefore, since the synthetic resin and the plating adhere through the metal particles, a metal plating film having excellent adhesion and wear resistance is generated.
[0017]
( First reference example )
A first reference example will be described with reference to FIG. A CFRP cylinder 11 is manufactured by impregnating a reinforced fiber such as a woven or filamentary carbon fiber in one direction with a resin, laminating a prepreg sheet that is a mixture of a semi-cured resin and a reinforced fiber, and curing it. The outer surface 12 of the CFRP cylinder 11 is polished. The polishing roughness is preferably about the roughness polished with water-resistant polishing paper equivalent to # 400. As described above, refer to FIG.
[0018]
After washing with a solvent such as toluene, a paint 15 prepared by previously mixing the copper particles 13 in the synthetic resin 14 is applied using an air spray gun. The paint 15 used here is a conductive paint having a product number of 599-A8574-1 manufactured by SPRAYLAT Corp. of the United States. The size of the copper particles 13 has a constant length of about 30 μm, and is a synthetic (urethane). ) It is blended in the resin 14 at 81% by weight. If the coating thickness is thin, sufficient conduction during copper plating cannot be obtained, and the subsequent processing accuracy becomes severe. On the other hand, when the applied thickness is thick, unevenness and unevenness are generated, and therefore, about 100 to 300 μm is preferable. Then, it was dried and allowed to stand at room temperature for curing. As described above, refer to FIG.
[0019]
Next, the coated surface of the CFRP cylinder 11 on which the coating material 15 is applied is polished on a rotating grindstone to cut the copper particles 13 to form a polished surface S that exposes the cross section. Unlike the method of eluting metal by etching, the present invention is characterized in that the cut cross section of metal particles is exposed by polishing. Therefore, depending on the shape of the plastic part, the means for polishing the coated surface can be polished manually by using a water-resistant polishing paper equivalent to # 400 or using a grinding stone, etc. . The thickness T of the coated layer after polishing is set to about 80 to 200 μm. As described above, refer to FIG.
[0020]
By this polishing of the coated surface, copper sulfate electroplating generally performed is performed on the polished surface where the cut cross section of the copper particles 13 is exposed (at 20 ° C. for 4 hours). After coating the copper plating layer 16 by 90 μm, the copper plating layer 16 is polished with a rotating grindstone so that the thickness t of the copper plating layer 16 is about 70 μm. As described above, refer to FIG.
[0021]
On the polished copper plating layer 16, a hard chrome plating of a sergeant bath generally performed is performed at 50 ° C. for 10 hours or more to cover a chromium plating layer 17 of about 130 μm. The coated hard chrome plating layer 17 is polished with a rotating grindstone and finished to a thickness of about 100 μm. As described above, refer to FIG.
[0022]
With respect to the first reference example thus obtained, the adhesion was evaluated by a method based on a peeling test using an adhesive tape disclosed in Japanese Patent Application Laid-Open No. 61-12872. The test results are shown in Table 1. The “comparative example” in Table 1 is the result of removing the copper particles 13 from the conductive paint 15 by centrifugal separation, and the other coating conditions, polishing or polishing conditions, and plating conditions are the same. The data regarding the sample of the first reference example is that the coating layer thickness after polishing is 80 μm, the copper plating thickness after polishing is 70 μm, and the hard chromium plating thickness after polishing is 100 μm. The number of the denominator in Table 1 indicates the number of test samples of the test piece, and the number is eight.

[0023]
As a result, the first reference example exhibited good adhesion with respect to the total number of test pieces on both the copper plating polished surface and the hard chrome plated polished surface. On the other hand, all of the comparative examples were unsatisfactory due to peeling.
[0024]
( Second reference example )
The second reference example uses metal particles having a diameter in the range of about 10 to 200 μm, whereas the first reference example uses metal particles having a length of 30 μm.
A carbon fiber prepreg impregnated with resin is laminated and cured to produce a CFRP cylinder 21. The outer surface 22 of the CFRP cylinder 21 is polished using water-resistant polishing paper equivalent to # 400. As described above, refer to FIG.
[0025]
The paint 25 to be applied after washing with a solvent such as toluene is 60 to 90% by weight of spherical copper particles 23 having a diameter of about 10 to 200 μm in a thermosetting epoxy resin 24 (EA-9394 manufactured by DEXTER Corp, USA). Mix and add toluene solvent. This paint 25 is applied to about 200 μm using an air spray gun. Then, it is dried and cured at 120 ° C. under the heating conditions of the manufacturer. The copper particles 23 used here are manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., and the trade name is Cu-At-100. As described above, refer to FIG.
[0026]
Next, the coated surface of the dried and hardened CFRP cylinder 21 is polished with a rotating grindstone. By polishing the coated surface, the copper particles 23, which are metal particles, are cut to form a polished surface S whose cross section is exposed. Then, the thickness T2 of the coated layer after polishing is set to about 80 to 200 μm. As described above, refer to FIG.
[0027]
After washing, the same copper sulfate electroplating as in the first reference example is performed on the exposed polished surface of the copper particles 23 (4 hours at 20 ° C.). After coating the copper plating layer 26 by about 90 μm, the plating layer t2 is made 70 μm or more by polishing with a rotating grindstone. As described above, refer to FIG.
[0028]
After further cleaning, a hard chrome plating of a conventional Sargent bath is performed on the polished copper plating layer 26 at 50 ° C. for 10 hours or more to cover the hard chromium plating layer 27 of about 130 μm. The coated hard chrome plating layer 27 is polished and finished so that the thickness of the hard chrome plating layer 27 is about 100 μm or more. As described above, refer to FIG.
[0029]
A second reference example obtained in this way, the adhesion was carried out similar test as in the first embodiment. The test results are shown in Table 2. Here, the “comparative example” for comparing the second reference example is obtained by adding a toluene solvent to the epoxy resin (EA-9394) without adding the copper particles 23, and other coating conditions are the same. is there. The data concerning the sample of the second reference example is that the coating thickness after polishing is 150 μm, the copper plating thickness after polishing is 70 μm, and the hard chromium plating after polishing is 100 μm.

[0030]
As a result, also in the second reference example , both the copper-plated polished surface and the hard chrome-plated polished surface exhibited good adhesion with respect to the total number of test pieces. On the other hand, all of the comparative examples were unsatisfactory due to peeling.
[0031]
From the results of these two reference examples , it is easy to form a copper plating and hard chrome plating layer on the outer surface of the CFRP cylinder, and it does not peel off with an adhesive tape or with a polishing grindstone during polishing. It was confirmed that a plating film was obtained.
[0032]
In the first and second reference examples described above, a coating material obtained by previously mixing metal particles in a synthetic resin and applying a paint is applied by air spray. This method is suitable for coating the outer surface of a part, but has a problem for narrow portions such as a small-diameter cylindrical inner surface. That is, the metal coating by plating is basically to uniformly and continuously disperse the metal particles as the base, and for this purpose, the angle and distance to the application surface of the spray gun must be constant. For this reason, the spray gun needs to be separated from the coating surface by at least about 10 cm, and for example, the inner surface of a cylinder having a diameter smaller than 10 cm cannot be sprayed. For this reason, the present invention further provides a metal coating method that does not depend on air spray, in other words, can be applied to a portion having a small diameter. Embodiments of the present invention will be described below.
[0033]
Here, the outline of the embodiment will be described before the description of the embodiment. The inner surface of the CFRP cylinder is polished to form a rough surface, and after cleaning, a thermosetting epoxy resin is applied to the entire inner surface. The application method is based on generally used flow coating or dip coating. Metal particles are sprinkled on the epoxy resin coating surface to impregnate the metal particles. Thereafter, the resin is cured by heating. Next, the coated surface is polished manually or by polishing using a mechanical device, and the metal particles are cut to expose the cross section. And after washing | cleaning, the metal is coat | covered by giving the chemical plating or electroplating generally performed to the grinding | polishing surface which this metal particle exposed.
[0034]
By this process, copper plating (metal) is deposited on the cut cross section of the copper particles exposed on the polished surface. Subsequently, the copper plating on each copper particle grows thick and wide with time, and the exposed copper particles are put together to bond the entire inner surface by copper plating. Therefore, since the epoxy resin and the copper plating adhere via the large copper particles, a metal plating film having excellent adhesion is formed on the inner surface of the CFRP cylinder.
[0035]
( Embodiment )
The embodiment will be described with reference to FIG. A carbon fiber prepreg sheet impregnated with resin is laminated and cured to produce a CFRP cylinder 31. The inner surface 32 of the CFRP cylinder 31 is polished with polishing paper equivalent to # 400. As described above, refer to FIG.
[0036]
After the polished inner surface 32 is washed with a solvent such as toluene, a thermosetting epoxy resin 34 (for example, EA-9394 manufactured by DEXTER Corp., USA) is applied. The method of application is by flow coating or dip coating which is generally performed in coating. As described above, refer to FIG.
[0037]
Next, the copper particles 33 are impregnated in the epoxy resin 34 while the epoxy resin 34 is not cured. Specifically, one end of the CFRP cylinder 31 is raised and held at an angle of about 60 degrees, and the copper particles 33 from above (the copper particles 33 are the same as those used in the second reference example , Fukuda Metal Foil Powder Industry) (Trade name: Cu-At-100 manufactured by Co., Ltd.) is dropped along the entire inner surface 32 of the CFRP cylinder 31. In this case, the inclination of the CFRP cylinder 31 is preferably in the range of about 30 to 80 degrees. This range is preferable because when the inclination angle is small, the copper particles 33 do not smoothly cover the surface of the epoxy resin 34, and when the inclination angle is large, the impregnation of the copper particles 33 into the epoxy resin 34 tends to be uneven. When the copper particles 33 dropped from above the CFRP cylinder 31 reach the lower part of the CFRP cylinder 31, the CFRP cylinder 31 is turned to similarly drop the copper particles 33, and this is sequentially repeated to form the inner surface 32 of the CFRP cylinder 31. The entire circumference is covered with copper particles 33. Further, when dropping the copper particles 33, a jig with holes, grooves or nets may be used in the CFRP cylinder 31. If the copper particles 33 are completely impregnated, the resin becomes insufficient, so that the excess copper particles 33 are not attached to the resin. When the copper particles 33 are sprinkled up to this stage, excess copper particles 33 are removed by, for example, raising the CFRP cylinder 31 vertically. As described above, refer to FIG.
[0038]
Then, the CFRP cylinder 31 is placed in a heating furnace and cured by heating at 120 ° C. for 1 hour in accordance with the curing conditions of epoxy resin 34: EA-9394. After curing, the surface is polished with a rotating grindstone to obtain a smooth surface. By this polishing, the copper particles 33, which are metal particles, are cut to form a polished surface S whose cross section is exposed. The thickness T3 of the epoxy resin layer containing the polished copper particles 33 is required to be at least about 80 μm for the subsequent electroplating. As described above, refer to FIG.
[0039]
Next, after washing, copper sulfate plating generally performed is applied. After adding 100 μm or more of the copper plating layer 36, the copper plating layer 36 is polished with a rotating grindstone so that the thickness t 3 of the copper plating layer 36 is about 80 μm. As described above, refer to FIG.
[0040]
Further, after washing, a hard chrome plating of a Sargent bath which is generally performed is performed on the ground copper plating layer 36, a hard chromium plating layer 37 of about 130 μm is added, and polished with a rotating grindstone, and a hard hardness of about 100 μm is applied. Finish to be a chrome plating layer 37. As described above, refer to FIG.
[0041]
The embodiment thus obtained was subjected to the same test as that of the first reference example for the adhesion. The test results are shown in Table 3.

[0042]
As a result, also in this embodiment , both the copper plating polished surface and the hard chrome plated polished surface exhibited good adhesion with respect to the total number of test pieces.
[0043]
【The invention's effect】
As described above, in the present invention, a synthetic resin is applied to the inner surface of a CFRP material having a small dimension by a general application method such as flow coating or dip coating, and metal particles are sprinkled on the coated surface. Impregnated with metal particles. After drying and curing, the metal particles are cut by cutting to expose the cross section, and the CFRP material can be coated with a metal by a general chemical plating or electroplating method. The cost is low without using complicated devices.
[0044]
Chemical plating or electroplating plating (metal) adheres to the cut cross section of the metal particles exposed on the polished surface, and the synthetic resin and the plating adhere through the metal particles mixed or impregnated in the synthetic resin. Therefore, a metal plating film with excellent adhesion is generated.
[0045]
In addition, a resin layer in which a metal is mixed or impregnated is formed on a plastic part, and the metal is coated thereon, so that not only carbon fiber reinforced plastic materials but also general plastic materials and other resin layers are formed. It is applicable and has a wide range of applications. In addition, since the resin is applied, the part may have an uneven shape, is not restricted by part selection, and has a wide application range.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first reference example according to the present invention .
FIG. 2 is a diagram showing a second reference example according to the present invention .
3 is a diagram illustrating a form of implementation of the present invention.
[Explanation of symbols]
11, 21, 31 CFRP cylinder 12, 22 CFRP cylinder outer surface 32 CFRP cylinder inner surface 13, 23, 33 Copper particles (metal particles)
14, 24, 34 Synthetic resin, epoxy resin 15, 25 Paint 16, 26, 36 Copper plating layer (electroplating layer)
17, 27, 37 Hard chrome plating layer S Polished surface T1, T2, T3 Thickness of coating layer (epoxy resin) after polishing

Claims (1)

Polishing the inner surface of carbon fiber reinforced plastic to form a rough surface,
After cleaning, apply an epoxy resin to this rough surface.
Sprinkling metal particles while the epoxy resin is not cured,
The epoxy resin is dried and cured by heating or standing at room temperature,
Forming on the polished surface exposed by cutting and exposing the metal particles by polishing the epoxy resin dried and cured,
A metal coating method for carbon fiber reinforced plastic, wherein the metal is coated by chemical plating or electroplating on the polished surface after cleaning.

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