INTEGRATED ARTICLE OF FRP WITH METAL MATERIAL AND METHOD FOR PRODUCING THE SAME

Abstract

A metal sheet (Al alloy A6061) with a thickness of 0.2 to 1.0 mm with one component epoxy adhesive painted on a surface thereof having been subjected to chemical treatment is joined by adhesion with a plate material of CFRP prepared by laminating CFRP prepregs having carbon fiber aligned in uni-direction or having crossing carbon fiber. A metal plate (a high strength Al alloy material) is joined by adhesion with the metal sheet to be an integrated object via a layer of cured adhesive of epoxy resin adhesive having a thickness after adhesion of 0.3 mm or more. The integrated object can endure large change of temperature because of deformation of the layer of cured adhesive. A basic technique is provided such that a structure of CFRP joined by adhesion with a high strength metal material that can endure a severe several thousand cycle thermal shock test is prepared, enabling an aircraft, an automobile and a moving-type robot to be of a lighter weight.

Claims

1. An integrated article of FRP joined by adhesion with a metal material formed by laminating: a plate material of FRP prepared by laminating CFRP prepregs having carbon fiber aligned in uni-direction so as to align direction of the carbon fiber, and a high strength Al alloy material joined by adhesion with the plate material of FRP at the plate face or side face thereof to form an integrated object; wherein the adhesive is epoxy resin adhesive and thickness of adhesive cured after adhesion is 0.3 mm or more.

2. An integrated article of FRP joined by adhesion with a metal material formed by laminating: a plate material of FRP prepared by laminating CFRP prepregs or CFRTP prepregs having carbon fiber aligned in uni-direction so as to align direction of the carbon fiber, a metal sheet with a thickness of 0.2 to 1.0 mm having one face thereof secured to the plate material of FRP and the other face having been subjected to chemical treatment, and a high strength Al alloy material joined by adhesion with the metal sheet at the other face thereof to form an integrated object; wherein the adhesive is epoxy resin adhesive and thickness of adhesive cured after adhesion is 0.3 mm or more.

3. An integrated article of FRP joined by adhesion with a metal material formed by laminating: a plate material of FRP prepared by laminating CFRP prepregs having carbon fiber aligned in uni-direction so as to cause the carbon fiber to cross each other or by laminating CFRP prepregs having woven cloth of carbon fiber, and a Ti alloy material joined by adhesion with the plate material of FRP at the plate face or side face thereof to form an integrated object; wherein the adhesive is epoxy resin adhesive and thickness of adhesive cured after adhesion is 0.3 mm or more.

4. An integrated article of FRP joined by adhesion with a metal material formed by laminating: a plate material of FRP prepared by laminating CFRP prepregs or CFRTP prepregs having carbon fiber aligned in uni-direction so as to align direction of the carbon fiber or by laminating CFRP or CFRTP prepregs prepregs having woven cloth of carbon fiber, a metal sheet with a thickness of 0.2 to 1.0 mm having one face thereof secured to the plate material of FRP and the other face having been subjected to chemical treatment, and a Ti alloy material joined by adhesion with the metal sheet at the other face thereof; wherein the adhesive is epoxy resin adhesive and thickness of adhesive cured after adhesion is 0.3 mm or more.

5. An integrated article of FRP joined by adhesion with a metal material formed by laminating: a plate material of FRP prepared by laminating CFRP prepregs having carbon fiber aligned in uni-direction and GFRP prepregs having glass fiber aligned in uni-direction crossing the carbon fiber, a Ti alloy material joined by adhesion with the plate material of FRP at the plate face or side face thereof to form an integrated object; wherein the adhesive is epoxy resin adhesive and thickness of adhesive cured after adhesion is 0.3 mm or more.

6. An integrated article of FRP joined by adhesion with a metal material formed by laminating: a plate material of FRP prepared by laminating CFRP prepregs having carbon fiber aligned in uni-direction and GFRP prepregs having glass fiber aligned in uni-direction crossing the carbon fiber, a metal sheet with a thickness of 0.2 to 1.0 mm having one face thereof secured to the plate material of FRP and the other face having been subjected to chemical treatment, and a Ti alloy material joined by adhesion with the metal sheet at the other face thereof to form an integrated object; wherein the adhesive is epoxy resin adhesive and thickness of adhesive cured after adhesion is 0.3 mm or more.

7. The integrated article of FRP joined by adhesion with a metal material according to claim 1, wherein thickness of the metal sheet is 0.3 to 2.0 mm.

8. The integrated article of FRP joined by adhesion with a metal material according to claim 2, wherein thickness of the metal sheet is 0.3 to 2.0 mm.

9. The integrated article of FRP joined by adhesion with a metal material according to claim 3, wherein thickness of the metal sheet is 0.3 to 2.0 mm.

10. The integrated article of FRP joined by adhesion with a metal material according to claim 4, wherein thickness of the metal sheet is 0.3 to 2.0 mm.

11. The integrated article of FRP joined by adhesion with a metal material according to claim 5, wherein thickness of the metal sheet is 0.3 to 2.0 mm.

12. The integrated article of FRP joined by adhesion with a metal material according to claim 6, wherein thickness of the metal sheet is 0.3 to 2.0 mm.

13. The integrated article of FRP joined by adhesion with a metal material according to claim 2, wherein the metal sheet is of a kind selected from Al alloy A5052, Al alloy A5083 and Al alloy A6061.

14. The integrated article of FRP joined by adhesion with a metal material according to claim 4, wherein the metal sheet is of a kind selected from Al alloy A5052, Al alloy A5083 and Al alloy A6061.

15. The integrated article of FRP joined by adhesion with a metal material according to claim 6, wherein the metal sheet is of a kind selected from Al alloy A5052, Al alloy A5083 and Al alloy A6061.

16. The integrated article of FRP joined by adhesion with a metal material according to claim 3, wherein the angle of crossing is 90 degrees.

17. The integrated article of FRP joined by adhesion with a metal material according to claim 4, wherein the angle of crossing is 90 degrees.

18. The integrated article of FRP joined by adhesion with a metal material according to claim 6, wherein the angle of crossing is 90 degrees.

19. A method for producing the integrated article of FRP joined by adhesion with a metal material according to claim 1, wherein said method comprises: a step of forming a surrounding wall by inserting the metal material or the metal sheet with the surface thereof having been subjected to chemical treatment into a metallic mold for joining by injection molding and forming a surrounding wall that can retain liquid with a height of 0.3 to 2.0 mm by injection molding, a step of filling adhesive by filling the surrounding wall on the metal material or metal sheet with epoxy resin adhesive before curing, a step of painting by painting the epoxy resin adhesive before curing onto a surface of one selected from the plate of FRP, the metal material and the metal sheet, a step of joining by pressing surrounding wall filled with the epoxy resin adhesive before curing onto the surface, a step of curing adhesive by heating the joined article along with the epoxy resin adhesive before curing to cause the epoxy resin adhesive to be cured.

20. A method for producing the integrated article of FRP joined by adhesion with a metal material according to claim 2, wherein said method comprises: a step of forming a surrounding wall by inserting the metal material or the metal sheet with the surface thereof having been subjected to chemical treatment into a metallic mold for joining by injection molding and forming a surrounding wall that can retain liquid with a height of 0.3 to 2.0 mm by injection molding, a step of filling adhesive by filling the surrounding wall on the metal material or metal sheet with epoxy resin adhesive before curing, a step of painting by painting the epoxy resin adhesive before curing onto a surface of one selected from the plate of FRP, the metal material and the metal sheet, a step of joining by pressing surrounding wall filled with the epoxy resin adhesive before curing onto the surface, a step of curing adhesive by heating the joined article along with the epoxy resin adhesive before curing to cause the epoxy resin adhesive to be cured.

21. A method for producing the integrated article of FRP joined by adhesion with a metal material according to claim 3, wherein said method comprises: a step of forming a surrounding wall by inserting the metal material or the metal sheet with the surface thereof having been subjected to chemical treatment into a metallic mold for joining by injection molding and forming a surrounding wall that can retain liquid with a height of 0.3 to 2.0 mm by injection molding, a step of filling adhesive by filling the surrounding wall on the metal material or metal sheet with epoxy resin adhesive before curing, a step of painting by painting the epoxy resin adhesive before curing onto a surface of one selected from the plate of FRP, the metal material and the metal sheet, a step of joining by pressing surrounding wall filled with the epoxy resin adhesive before curing onto the surface, a step of curing adhesive by heating the joined article along with the epoxy resin adhesive before curing to cause the epoxy resin adhesive to be cured.

22. A method for producing the integrated article of FRP joined by adhesion with a metal material according to claim 4, wherein said method comprises: a step of forming a surrounding wall by inserting the metal material or the metal sheet with the surface thereof having been subjected to chemical treatment into a metallic mold for joining by injection molding and forming a surrounding wall that can retain liquid with a height of 0.3 to 2.0 mm by injection molding, a step of filling adhesive by filling the surrounding wall on the metal material or metal sheet with epoxy resin adhesive before curing, a step of painting by painting the epoxy resin adhesive before curing onto a surface of one selected from the plate of FRP, the metal material and the metal sheet, a step of joining by pressing surrounding wall filled with the epoxy resin adhesive before curing onto the surface, a step of curing adhesive by heating the joined article along with the epoxy resin adhesive before curing to cause the epoxy resin adhesive to be cured.

23. A method for producing the integrated article of FRP joined by adhesion with a metal material according to claim 5, wherein said method comprises: a step of forming a surrounding wall by inserting the metal material or the metal sheet with the surface thereof having been subjected to chemical treatment into a metallic mold for joining by injection molding and forming a surrounding wall that can retain liquid with a height of 0.3 to 2.0 mm by injection molding, a step of filling adhesive by filling the surrounding wall on the metal material or metal sheet with epoxy resin adhesive before curing, a step of painting by painting the epoxy resin adhesive before curing onto a surface of one selected from the plate of FRP, the metal material and the metal sheet, a step of joining by pressing surrounding wall filled with the epoxy resin adhesive before curing onto the surface, a step of curing adhesive by heating the joined article along with the epoxy resin adhesive before curing to cause the epoxy resin adhesive to be cured.

24. A method for producing the integrated article of FRP joined by adhesion with a metal material according to claim 6, wherein said method comprises: a step of forming a surrounding wall by inserting the metal material or the metal sheet with the surface thereof having been subjected to chemical treatment into a metallic mold for joining by injection molding and forming a surrounding wall that can retain liquid with a height of 0.3 to 2.0 mm by injection molding, a step of filling adhesive by filling the surrounding wall on the metal material or metal sheet with epoxy resin adhesive before curing, a step of painting by painting the epoxy resin adhesive before curing onto a surface of one selected from the plate of FRP, the metal material and the metal sheet, a step of joining by pressing surrounding wall filled with the epoxy resin adhesive before curing onto the surface, a step of curing adhesive by heating the joined article along with the epoxy resin adhesive before curing to cause the epoxy resin adhesive to be cured.

25. The method for producing the integrated article of FRP joined by adhesion with a metal material according to a claim 19, wherein the method further comprises a step of degassing of gas in the epoxy resin adhesive before curing by repeated operation of decompressing and returning to an ordinary pressure for the epoxy resin adhesive before curing, after the step of filling with adhesive and the step of painting adhesive.

26. The method for producing the integrated article of FRP joined by adhesion with a metal material according to a claim 20, wherein the method further comprises a step of degassing of gas in the epoxy resin adhesive before curing by repeated operation of decompressing and returning to an ordinary pressure for the epoxy resin adhesive before curing, after the step of filling with adhesive and the step of painting adhesive.

27. The method for producing the integrated article of FRP joined by adhesion with a metal material according to a claim 21, wherein the method further comprises a step of degassing of gas in the epoxy resin adhesive before curing by repeated operation of decompressing and returning to an ordinary pressure for the epoxy resin adhesive before curing, after the step of filling with adhesive and the step of painting adhesive.

28. The method for producing the integrated article of FRP joined by adhesion with a metal material according to a claim 22, wherein the method further comprises a step of degassing of gas in the epoxy resin adhesive before curing by repeated operation of decompressing and returning to an ordinary pressure for the epoxy resin adhesive before curing, after the step of filling with adhesive and the step of painting adhesive.

29. The method for producing the integrated article of FRP joined by adhesion with a metal material according to a claim 23, wherein the method further comprises a step of degassing of gas in the epoxy resin adhesive before curing by repeated operation of decompressing and returning to an ordinary pressure for the epoxy resin adhesive before curing, after the step of filling with adhesive and the step of painting adhesive.

30. The method for producing the integrated article of FRP joined by adhesion with a metal material according to a claim 24, wherein the method further comprises a step of degassing of gas in the epoxy resin adhesive before curing by repeated operation of decompressing and returning to an ordinary pressure for the epoxy resin adhesive before curing, after the step of filling with adhesive and the step of painting adhesive.

Description

BRIEF EXPLANATION OF DRAWINGS

[0159] FIG. 1 shows a pair (test piece) formed by joining metal pieces by adhesion for measuring shear strength between the metals.

[0160] FIG. 2 shows a pair formed by joining a CFRP material with a metal piece by adhesion for measuring tensile strength thereof.

[0161] FIG. 3 is a view of a structure showing a CFRP material composed of long carbon fibers aligned in a direction and a cured object of thermosetting plastics.

[0162] FIG. 4 is a view of a structure example in which CFRP prepregs having long carbon fibers aligned in a direction are layered so as to cross each other at an angle of 90 degrees.

[0163] FIG. 5 is a view of structure showing a CFRP material structure as an example of structure in which cloth type CFRP prepregs are layered.

[0164] FIG. 6 is a view of structure showing a CFRP material structure, in which the left side portion is one formed by layering uni-directional CFRP prepregs with fiber direction rotated by 90 degrees sequentially, and the right side portion is one formed by layering uni-directional CFRP prepregs aligned for fiber direction.

[0165] FIG. 7 is a view of structure showing a CFRP material structure, in which the left side portion is one formed by layering CFRP prepregs having long carbon fibers aligned in a uni-direction manner, and the right side portion is one formed by layering uni-directional CFRP prepregs and uni-directional GFRP prepregs so as to cross each other for joining with a plate material of Ti alloy.

[0166] FIG. 8 shows an example of a simplest form a pair formed by adhesion with a layer of cured adhesive sandwiched.

[0167] FIGS. 9(a) to 9(c) show a schematical model of a portion of cured object of adhesive (50 mm×50 mm×1.0 mm) extracted from a pair formed by adhesion of a metal plate with a CFRP plate, in which FIGS. 9(a) to 9(c) show its form at curing temperature of +150° C. and at a temperature of cooled state −50° C.

[0168] FIGS. 10(a) and 10(b) show a schematical model of a portion of cured object of adhesive (25 mm×25 mm×1.0 mm) extracted from a pair formed by adhesion of a metal plate with a CFRP plate, in which FIGS. 10(a), 10(b) show its form at curing temperature of +150° C. and at a temperature of cooled state −50° C.

[0169] FIGS. 11(a) and 11(b) show a schematical model of a portion of cured object of adhesive (25 mm×25mm×0.5 mm) extracted from a pair formed by adhesion of a metal plate with a CFRP plate, in which FIGS. 11(a), 11(b) show its form at curing temperature of +150° C. and at a temperature of cooled state −50° C.

[0170] FIGS. 12(a) to 12(c) show a schematical model of a portion of cured object of adhesive (50 mm×50mm×1.0 mm extracted from a pair formed by adhesion of a metal plate with a CFRP plate, in which FIGS. 12(a), 12(b) show its form at curing temperature of +150° C. and at a temperature of cooled state −50° C.

[0171] FIGS. 13(a) to 13(c) show a schematical model of a portion of cured object of adhesive (50 mm×50×0.5 mm) extracted from a pair formed by adhesion of a metal plate with a CFRP plate, in which FIGS. 13(a) to 13(c) show its form at curing temperature of +150° C. and at a temperature of cooled state −50° C.

[0172] FIGS. 14(a) to 14(c) show a schematical model of a portion of cured object of adhesive (100 mm×100×0.5 mm) extracted from a pair formed by adhesion of a metal plate with a CFRP plate, in which FIGS. 14(a) to 14(c) show its form at curing temperature of +150° C. and at a temperature of cooled state −50° C.

[0173] FIG. 15 shows a view of structure in case of joining a CFRP plate with a metal plate by adhesion similarly as in FIG. 8 with a pool shaped square frame to be filled with adhesive securing thickness thereof.

[0174] FIG. 16 shows a view of structure in case of joining a CFRP plate with a metal plate by adhesion similarly as in FIG. 8 with a pool shaped, deformed square frame to be filled with adhesive securing thickness thereof.

[0175] FIG. 17 shows an example of the square frame shown in bin FIG. 15 with an island for securing thickness disposed in the center thereof.

[0176] FIG. 18 shows a view of structure in case of joining a metal plate with a plate of CFRP or CFRTP with a metal sheet joined by adhesion thereto, in which a pool shaped square frame to be filled with adhesive is formed so as to secure thickness thereof.

[0177] FIG. 19 shows an example in which a metal plate is joined by adhesion via a metal sheet to the right side portion of a plate of CFRP having a laminated

DETAILED EXPLANATION OF EMBODIMENTS

[0178] The present invention will be explained for best modes of embodiments bellow.

EXPERIMENTAL EXAMPLES

[0179] Experimental examples of the present will be explained below.

(a) Observation with an Electron Microscope

[0180] An electron microscope was used mainly for observing a surface of a base material. Observation was conducted using a scanning electron microscopes (SEM) “SSM-7000F” (manufactured by Nihon Denshi Co. Ltd., main company in Tokyo, Japan) with 1 to 2 kV.

(b) Measurement of Joining Strength

[0181] Breaking force in tensile breaking of a joined article by adhesive (test piece shown in FIG. 1) measured with a tensile test instrument was taken as shear strength of adhesion. Further, breaking force in tensile breaking of a joined article by adhesive (test piece shown in FIG. 2) measured with a tensile test instrument was taken as tensile strength of adhesion. Used tensile test instrument was “AG-500N/1kN” (manufactured by Shimadzu-seisakusho Co. Ltd.: main company in Kyoto, Japan), and measurement was conducted at a tension speed of 10 mm/min.

(c) Measurement of Shear Stickiness of Adhesion

[0182] Measurement of “shear stickiness of adhesion” referred to in the present invention is a test in which, with strength of tensile strength of adhesion regarding a joined article by adhesion (test piece shown in FIG. 1) measured preliminarily, force of about 75% of the above is applied to test piece repeatedly and successively, without tensile breaking of the test piece with a tensile test instrument. Operation of a tensile test instrument is conducted setting mode in operation software so as to perform the above operation, setting highest tensile force to the above one, lowest tensile force to about ⅔ thereof and tension speed to ±10 mm/min. If the test piece is not broken with this, a test is conducted adding about 2 MPa to the above highest tensile force and applying same repeated load for 300 times. In a case where the test piece is not broken even with this, same operation is repeated adding further about 200 MPa. Thus, such operation is conducted successively until the test piece shown in FIG. 1 is broken. When the test piece is broken, acquired highest tensile force before breaking is indicated by MPa, which is taken as “shear stickiness of adhesion” in this measurement method. Used tensile test instrument is “AG-500N/1kN” mentioned above.

(d) Nondestructive Test

[0183] Detachment of a test piece can be confirmed sufficiently, as a simple manner, by a method of painting aqueous penetrating liquid on outer portion of a layer of adhesion, wiping it off and seeing whether colored portion is wiped out or not. However, in a case where it is desired to confirm to what extent detachment is spread, it was confirmed using a nondestructive test instrument. Used instrument is a supersonic type of nondestructive test instrument “MS Line” (manufactured by Hitachi Power Solutions Co. Ltd. (main company in Ibaraki, Japan).

[Thermal Shock Cycle Test]

[0184] A small type cooling-heating thermal shock test instrument “TSE-12-A” manufactured by Espec Co. Ltd. (main company in Osaka, Japan) was used for thermal shock cycle test in this experiment. Condition of the thermal shock cycle test conducted in a standard manner was such that temperature of cooling room is −50° C., temperature of high temperature room is 150° C., staying time in each room is 25 minutes and time for transfer is 5 minutes. The test instrument itself is placed in a room where temperature is constantly adjusted to 27° C. and automatic operation was conducted by raising the temperature of the cooling room periodically to the room temperature to melt frozen portion in the instrument in a natural manner. However, such as an accident that portion in the instrument is frozen may occur in a high humidity time, in order to prevent such accident completely, test was conducted by keeping a safe operation by ceasing operation of the test instrument in weekend days, new year days, successive holidays in May, August, etc.

Experiment Example

Surface Treatment of Each Material

Experiment Example 1

Surface Treatment of Ai Alloy A7075 (NAT Treatment (Preliminary Treatment for Adhesion))

[0185] Plates of Al alloy A7075 of kinds of shapes with thickness 1 to 3 mm were purchased and subjected to mechanical working to obtain Al alloy pieces having necessary form. An aqueous solution containing degreaser for aluminum “NA-6” (made by Meltex Co. Ltd.: main company in Tokyo, Japan) by 10% was filled to be at 60° C. in a tank for immersion, in which the above aluminum alloy pieces were immersed for 5 minutes, and after then the pieces were rinsed with tap water (Ota city, Gumma prefecture, Japan) (abbreviated below). Next, an aqueous solution of hydrochloric acid having a concentration of 1% was made ready to be at 40° C. in another tank, in which the pieces were immersed for 1 minute, and after then the pieces were rinsed with water. Next, an aqueous solution of caustic soda having a concentration of 1.5% was made ready to be at 40° C. in still another tank, in which the pieces were immersed for 4 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of nitric acid having a concentration of 3% was made ready to be at 40° C. in still another tank, in which the pieces were immersed for 3 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of hydrazine hydrate having a concentration of 3.5% was made ready to be at 60° C. in still another tank, in which the pieces were immersed for 2 minutes, and then the pieces were immersed in an aqueous solution of hydrazine hydrate having a concentration of 0.5% at 33° C. made ready in still another tank for 0.5 minute, and after then the pieces were rinsed with water. Further, after the pieces were immersed in hydrogen peroxide water having a concentration of 5% for 5 minutes, the pieces were rinsed well with water. The aluminum alloy pieces having been subjected to the above treatment were placed in a warm air drier set to be at a temperature of 67° C. for 15 minutes and dried there. After this, the pieces were wrapped together with clean aluminum foil to be stored.

Experiment Example 2

Surface Treatment of Al Alloy A7075 (Treatment of NMT 2 (Preliminary Treatment for Joining by Injection Molding))

[0186] Plates of Al alloy A7075 of kinds of shapes with thickness 1 to 3 mm were purchased and subjected to mechanical working to obtain Al alloy pieces having necessary form. An aqueous solution containing the above degreaser for aluminum “NA-6” by 10% was filled to be at 60° C. in a tank for immersion, in which the above aluminum alloy pieces were immersed for 5 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of hydrochloric acid having a concentration of 1% was made ready to be at 40° C. in another tank, in which the pieces were immersed for 1 minute, and after then the pieces were rinsed with water. Next, an aqueous solution of caustic soda having a concentration of 1.5% was made ready to be at 40° C. in still another tank, in which the pieces were immersed for 4 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of nitric acid having a concentration of 3% was made ready to be at 40° C. in still another tank, in which the pieces were immersed for 3 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of hydrazine hydrate having a concentration of 3.5% was made ready to be at 60° C. in still another tank, in which the pieces were immersed for 1 minute, and then the pieces were immersed in an aqueous solution of hydrazine hydrate having a concentration of 0.5% at 33° C. made ready in still another tank for 0.5 minute, and after then the pieces were rinsed with water. The aluminum alloy pieces having been subjected to the above treatment were placed in a warm air drier set to be at a temperature of 67° C. for 15 minutes and dried there. After this, the pieces were wrapped together with clean aluminum foil to be stored.

Experiment Example 3

Surface Treatment of Ai Alloy A6061 (NAT Treatment (Preliminary Treatment for Adhesion))

[0187] Plates of Al alloy A6061 of kinds of shapes with thickness 0.5 to 2 mm were purchased and subjected to mechanical working to obtain Al alloy pieces having necessary form. An aqueous solution containing the above degreaser for aluminum “NA-6” by 10% was filled to be at 60° C. in a tank for immersion, in which the above aluminum alloy pieces were immersed for 5 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of hydrochloric acid having a concentration of 1% was made ready to be at 40° C. in another tank, in which the pieces were immersed for 1 minute, and after then the pieces were rinsed with water. Next, an aqueous solution of caustic soda having a concentration of 1.5% was made ready to be at 40° C. in still another tank, in which the pieces were immersed for 4 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of nitric acid having a concentration of 3% was made ready to be at 40° C. in still another tank, in which the pieces were immersed for 3 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of hydrazine hydrate having a concentration of 3.5% was made ready to be at 60° C. in still another tank, in which the pieces were immersed for 2 minutes, and then the pieces were immersed in an aqueous solution of hydrazine hydrate having a concentration of 0.5% at 33° C. made ready in still another tank for 0.5 minute, and after then the pieces were rinsed with water. Further, after the pieces were immersed in hydrogen peroxide water having a concentration of 5% for 5 minutes, the pieces were rinsed well with water. The aluminum alloy pieces having been subjected to the above treatment were placed in a warm air drier set to be at a temperature of 67° C. for 15 minutes and dried there. After this, the pieces were wrapped together with clean aluminum foil to be stored.

Experiment Example 4

Surface Treatment of 64 Ti Alloy (NAT Treatment (Preliminary Treatment for Adhesion))

[0188] Plates of 64 Ti alloy having various shapes (Ti alloy pieces) with thickness 1 to 3 mm were prepared. An aqueous solution containing the above degreaser for aluminum “NA-6” by 10% was filled to be at 60° C. in a tank for immersion, in which the above Ti alloy pieces were immersed for 5 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of ammonium hydrogen bifluoride having a concentration of 5% was made ready to be at 6 5° C. in another tank, in which the 64 Ti alloy pieces were immersed for 5 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of nitric acid having a concentration of 3% was made ready to be at 40° C. in still another tank, in which the 64 Ti alloy pieces were immersed for 3 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution containing potassium permanganate by 2% and caustic potash by 3% was made ready to be 70° C. in another tank, in which the Ti alloy pieces were immersed for 30 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution containing sodium chlorite by 5% and caustic soda by 10% was made ready to be 55° C. in another tank, in which the 64 Ti alloy pieces were immersed for 10 minutes, and after then the pieces were rinsed with water. Next, hydrogen peroxide water having a concentration of 1.5% was made ready, in which the 64 Ti alloy pieces were immersed for 1 minute, and after then the pieces were rinsed with water. The aluminum alloy pieces having been subjected to the above treatment were immersed in a tank provided with an ultrasonic oscillation end for several minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of triethanolamine having a concentration of 0.2% was made ready to be 40° C. in another tank, in which the 64 Ti alloy pieces were immersed for 15 minutes, and after then the pieces were rinsed well with water. Then, the 64 Ti alloy pieces were placed in a warm air drier set to be at a temperature of 80° C. for 15 minutes and dried there, after which the pieces were wrapped together with clean aluminum foil to be stored.

Experiment Example 5

Surface Treatment of 64 Ti Alloy (New NMT Treatment (Preliminary Treatment for Joining by Injection Molding))

[0189] Plates of 64 Ti alloy having various shapes (Ti alloy pieces) with thickness 1 to 3 mm were prepared. An aqueous solution containing the above degreaser for aluminum “NA-6” by 10% was filled to be at 60° C. in a tank for immersion, in which the above Ti alloy pieces were immersed for 5 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of ammonium hydrogen bifluoride having a concentration of 5% was made ready to be at 6 5° C. in another tank, in which the 64 Ti alloy pieces were immersed for 4 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution of nitric acid having a concentration of 3% was made ready to be at 40° C. in still another tank, in which the 64 Ti alloy pieces were immersed for 3 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution containing potassium permanganate by 2% and caustic potash by 3% was made ready to be 70° C. in another tank, in which the Ti alloy pieces were immersed for 30 minutes, and after then the pieces were rinsed with water. Next, an aqueous solution containing sodium chlorite by 5% and caustic soda by 10% was made ready to be 55° C. in another tank, in which the 64 Ti alloy pieces were immersed for 10 minutes, and after then the pieces were rinsed with water. The 64 Ti alloy pieces having been subjected to the above treatment were placed in a warm air drier set to be at a temperature of 80° C. for 15 minutes and dried there, after which the pieces were wrapped together with clean aluminum foil to be stored.

Experiment Example 6

Preparation of Pairs of CFRP Plate with AL Alloy A7075 Plate Joined by Adhesion

[0190] Obtaining uni-directional prepreg of CFRP “P2255S-25” having a thickness of 0.2 mm (made by Toray Co. Ltd.: main company in Tokyo, Japan)”, plates of CFRP with direction of CF aligned having a dimension of 110 mm×40 mm with a thickness of 10 mm were prepared. Then sheet pieces of Al alloy A6061 having a dimension of 10 mm×40 mm with a thickness of 0.5 mm having been subjected to the surface treatment explained in Experiment Example 3 were made ready, the above one component epoxy adhesive “EW2040” was painted on one face of these sheet pieces of alloy, the painted sheet pieces were laminated on the CFRP plates respectively, which were integrated as laminated objects by an autoclave method. Cutting each of the laminated objects to ones of a dimension 100 mm×35, a large number of CFRP plates having a thickness of 10.5 mm with a sheet of Al alloy attached thereto were obtained (upper side member in FIG. 18).

[0191] Next, plates of Al alloy A7075 having a thickness of 2 mm, as a material shown in FIG. 18, were obtained and from these a large number of small pieces having a dimension of 100 mm×35 mm. Conducting chemical treatment for these by a method in Experiment Example 1 to be objects by NAT treatment. Then five of them were laminated to form a plate having a thickness of 10 mm for each. For this, each face of them was joined by all face to all face adhesion with the above epoxy adhesive “RW2040”, thus obtaining rectangular plate having dimension of 100 mm×35 mm×10 mm. As it is considered that a layered object obtained lamination has an increased thickness by adhesive, the form of 100 mm×35 mm×10 mm was prepared by mechanical working. In order to form a concave portion surrounded by a wall (referred to as a pool frame), a metal mold for joining by injection molding. That is, the wall shaped object formed in a square shape shown on the left side in FIG. 18 was formed with injected resin such as a kind of a weir for preventing liquid-like adhesive from flowing out.

[0192] This pool frame was formed by injection molding. That is, surface of [a plate of Al alloy A7075 having a dimension of 100 mm×35 mm×10 mm obtained by lamination was subjected to treatment of NAT 2 and then the plate of Al alloy was inserted into a metal mold for joining by injection molding, into which the above PPS resin “SGX120”as one for joining by injection molding to form the pool frame. Thus, the pool-like square frame as a wall-shaped object depicted in a left side position of FIG. 15 was formed. Subtle adjustment of height of the resin wall of the square frame can be conducted at a time when the metallic mold for joining by injection molding is prepared, or may be conducted by shaving the molded frame to be of a desired height after it was formed by injection molding. In this experiment, after forming an object of initial design having a height of 1.5 mm, it was shaved as mechanical working to be of a height of 0.5 mm. In the next, it subjected to NAT treatment (preliminary treatment for adhesion) explained in Experiment 1 and then dried.

[0193] An object obtained through working having been subjected to NAT treatment was kept to be in a horizontal state and a solution (exactly, a suspension) consisting of one component epoxy adhesive “EW2040” by 2% and MIBK solvent by 98% was painted with a writing brush on a portion of the pool-shaped square frame corresponding to a bottom (penetration into irregularities of the surface), and solvent was dried in a warm air drier at 50° C. for 20 minutes to be volatilized.

[0194] The plate of Al alloy A7075 having the pool-shaped square frame thereon filled with adhesive was placed on a horizontal stand, and the plate of CFRP with an aluminum sheet attached thereto on which adhesive is painted thinly was placed (laminated) in a reversed state, so that the two materials shown in FIG. 18 were laminated to form a pair joined by adhesion (FIG. 8). Then, an upper plate as a weight was placed further thereon. In order to prevent the pool-shaped square frame from being broken under the weight of the CFRP material and the upper plate, a space material of a substantially same thickness as the CFRP material was intervened therewith, and these members were fixed by a jig so as not to move each other. These members were placed in a large desiccator kept at a temperature of 50° C., pressure therein was lowered to 0.05 atmosphere with a vacuum pump, then air was supplied into the large desiccator and pressure was lowered again, and then was returned to a normal pressure (atmosphere) again, such operation being conducted for three cycles. This cyclic operation is for removing air having entered into the face of adhesion. In the next, these members were taken out and placed in a hot air drier set to a temperature of 170° C., where curing treatment of adhesive with 170° C. was×25 minutes was conducted. After this the door of the hot air drier was opened to conduct cooling. In the next day, the assembled members were taken apart and the pair firmed by adhesion was taken out. While adhesive having overflowed was cured to be solidified in a periphery of the square frame, part that can be shaped off by mechanical working was removed and part having been cured to be solidified between the two materials were kept as it is. In this Experiment, the object of cured adhesive has a form of a rectangular sheet shown in FIGS. 11(a) and 11(b).

Experiment Example 7

Preparation of Pairs of CFRP Plate with 64 Ti Alloy Plate Joined by Adhesion

[0195] CFRP prepreg of plain weave “C06363” (made be Toray Co. Ltd.: main company in Tokyo, Japan) was obtained and plates of CFRP each having a dimension of 110 m×40 mm with a thickness of 10 mm were prepared. On the other hand, sheets of Al alloy A6061 having a dimension of 110 mm×40 mm with a thickness of 0.5 mm having been subjected to surface treatment by chemical treatment method (NAT treatment) explained in Experiment Example 3 were prepared, and one component epoxy adhesive “EW2040” was painted thereon. A sheet of them was laminated on one of the above plates of CFRP to be integrated to a laminated object as it is by an autoclave method. By cutting the obtained object, a CFRP plate having a thickness of 10.5 mm with a sheet of Al alloy A6061 attached thereto was obtained respectively.

[0196] On the other hand, 64 Ti alloy pieces having a dimension of 100 mm×35 mm×10 mm were obtained through mechanical working. A metallic mold for joining by injection molding prepared for forming a pool-shaped concave on this 64 Ti alloy plate was formed in a similar manner for the case of Al alloy plate shown in FIG. 18. Each of these plates of 64 Ti alloy was subjected to New NMT treatment by a method explained in Experiment Example 5, inserted into the above-mentioned metallic mold for injection molding and “SGX120” as a PPS resin for joining by injection molding was injected therein. Thus, an object was prepared with a pool-shaped square frame shown in FIG. 18 formed thereon. Here, desired shape and dimension of this square frame was obtained through the metallic mold for joining by injection molding and mechanical working. In this example, an initial height of 2 mm was made a height Of 0.5 mm through mechanical working after injection molding. In the next, after being subjected to NAT treatment explained in Experiment Example 4, it was dried.

[0197] Obtained object having been subjected to NAT treatment was kept in a horizontal state, a solution (exactly, a suspension) consisting of one component epoxy adhesive “EW2040” by 2% and MIBK solvent by 98% was painted with a writing brush on a portion of the pool-shaped square frame corresponding to a bottom (penetration into irregularities of the surface), and solvent was dried in a warm air drier at 50° C. for 20 minutes to be volatilized. In the next, “EW2040” itself was poured into the pool-shaped square frame to a full state. On the other hand of this operation, a CFRP plate having a thickness of 10.5 mm with a sheet of Al alloy A6061 attached thereto as obtained beforehand was taken out, the above adhesive solution diluted with solvent is painted on a necessary place on the surface of the Al alloy, and this also was dried in a warm air drier at 50° C. for 20 minutes causing solvent to be volatilized. The plate of 64Ti alloy having the pool-shaped square frame thereon filled with adhesive was placed on a horizontal stand, and the plate of CFRP with an aluminum sheet attached thereto on which adhesive is painted thinly was placed in a reversed state, so that the two materials shown in FIG. 18 were laminated to form a pair joined by adhesion.

[0198] Then, a fixing jig and an upper plate as a weight were placed on them further. The laminated object as a pair to be joined by adhesion was fixed with a jig as a whole and a spacer intervened so that the square frame may not be broken with weight of the CFRP material and the upper plate and gap is not created. These members were placed in a large desiccator kept at a temperature of 50° C., pressure therein was lowered to 0.05 atmosphere with a vacuum pump, then air was supplied into the large desiccator and pressure was lowered again, and then was returned to a normal pressure again, such operation being conducted for three cycles. In the next, these members were taken out and placed in a hot air drier set to a temperature of 170° C., where curing treatment of adhesive with 170° C. was x 25 minutes was conducted. After this the door of the hot air drier was opened to conduct cooling. In the next day, the assembled members were taken apart and the pair firmed by adhesion was taken out. While adhesive having overflowed was cured to be solidified in a periphery of the square frame, part that can be shaped off by a luta was removed and part having been cured to be solidified between the two materials were kept as it is. In this, as joining of CFRTP with Al alloy A6061 is a known art presented by the present inventor, thus it is not explained in detailed here (see Patent Document 15).

Experiment Example 8

−50° C./+150° C. Thermal Shock Test 3000 Cycle Test

Experiment Example 8

[0199] Two pairs joined by adhesion for each of the obtained in Experiment Examples 77 and 8, that is, 4 pairs joined by adhesion in total were subjected to 3000 cycle test for −50° C./+150° C. thermal shock. The test pieces were taken out also at a midway time when 1000 cycles finished and 2000 cycles finished. Thus, while test was conducted by inspecting with a nondestructive test instrument whether there is an abnormal portion or not, such abnormal test piece was not found, including those for which 3000 cycles finished.

[0200] With Experiment Example 6, the uni-directional CFRP material was joined by adhesion with an Al alloy A7075 via an object of cured adhesive having a thickness of 0.5 mm. While it was assumed the object of cured adhesive has a sufficient resistance ability to thermal shock as it has a same form as one shown in FIGS. 11(a) and 11(b), there was actually no appearance of breaking in the layer of cured adhesive. This is as considered, due to such thickness of the layer of cured adhesive, so that usefulness of the present invention could be confirmed.

[0201] Further, with Experiment Example 7, the CFRP material with cloth-type CFRP prepregs laminated was joined by adhesion with an 64 Ti alloy through forming an layer of cured adhesive having a dimension of 25 mm×25 mm with a thickness of 0.5 mm. This layer of cured adhesive is assumed to have resistance ability to thermal shock higher than the layer of cured adhesive having a dimension of 50 mm×10 mm 50 mm×0.5 mm wider than this shown in FIGS. 13(a) to 13(c). While there was actually no appearance of breaking in the layer of cured adhesive in the above experiments, this is as considered, due to the layer of cured adhesive having such thickness, so that usefulness of the present invention could be confirmed.

[Thought Experiment 1]

[0202] From the above results of experiment, thought is possible as follows. For a plate of CFRP formed by adhesion of laminated uni-directional prepregs with direction of fibers aligned, its coefficient of linear expansion in the direction of fibers becomes 0.1×10.sup.−5K.sup.−1 to substantially that of CD itself. In all direction perpendicular to this direction, coefficient of linear expansion becomes (5 to 8)×10.sup.−5K.sup.−1 on which coefficient of linear expansion of cured epoxy adhesive has a main influence, giving a large difference between these. Assuming that this coefficient of linear expansion appears on a face of the CFRP plate or has an influence, the present inventor has argued about change of form of a layer of cured adhesive occupying a space of between the CFRP material and the metal material through assuming and experiment. In short, it has been argued that form of a cured object of one component epoxy adhesive (layer of cured adhesive) having a high heat resistance is deformed by external force loaded on the face of adhesion as shown in FIGS. 9(a) to 14(c) by modelling. In this, consideration was made about whether the layer of cured adhesive is broken or not, and about whether concentration of stress exceeding strength of adhesion occurs or not specifically in angular portions at four corners thereof. Further, consideration was made about what characteristics a layer of cured adhesive as an object of cured adhesive being a solid body, and metal of lead, pure aluminum, soft iron, etc., exhibits when deformation of form is forced on them. One of characteristics is near to that of a metal material such that at first it creates elastic deformation according to Young's modulus in a manner of a metal and plastic deformation for larger one. As another characteristic of the layer of cured adhesive, when deformation in form is forced such as hard rubber having a high degree of crosslinking, it is broken if the deformation is large one as tearing off crosslinking portions It becomes a key to decide which this object of cured adhesive is. Of course, the present inventor decided that, for synthetic resin material containing no reinforcing fiber, deformation created when forced to change form by external force or changing temperature is near to that of hard rubber, that is, of latter case. Therefore, forecasting was made about whether portion of adhesion is delaminated or not, by modelling as shown in FIGS. 10(a) to 14(c) and seeing dimensions and change in form.

[0203] For FRP shown in FIG. 7, form of an integrated FRP, in which CFRP prepregs and GFRP prepregs are laminated with directions of fiber crossed at an angle of 90 degrees, in the right side of the FRP. For coefficient of linear expansion of the upper face, that is a face of the plate, coefficient of linear expansion is taken as 0.1×10.sup.−5K.sup.−1 for lengthwise direction (x axis direction) and (0.7 to 0.8)×10.sup.−5 K.sup.−1 in a level of GF for width direction (y axis direction), seeing it to be coincident with the above consideration. When a structure of a wing of an airplane, etc., is formed with CFRP actually, a large FRP having a form shown in FIG. 7 (for example, length of 2 m, width of 2 m and thickness of 30 mm with GFRP prepreg on the right side having a length in x axis direction of 50 cm) is formed and a portion of FRP at the right end with both CF and GF used has a dimension of length of 2 m, width of 50 mm and thickness of 10 mm. As shown in FIG. 19, an article of FRP material joined by adhesion with 64 Ti alloy plate is formed in which a 64 Ti alloy plate having a three semi-island shape is joined by adhesion in the right end thereof in a large area near to the Ti alloy plate. In this, trying to attain the object actually, strength of adhesion of epoxy adhesive between the FRP material and the 64 Ti alloy plate is required to be reliable. In order to improve fastening strength of the fastened portion explained above, a sheet of Al alloy A6061 should be joined by adhesion before adhesion of 64 Ti alloy plate at a necessary position thereof. Therefore, a sheet of Al alloy A6061 having a dimension of length of 2 mm, width of 100 mm and thickness of 0.5 mm is prepared and, after having been subjected to NAT treatment, is joined by a wet adhesion method with a portion of FRP, thus forming a large plate of FRP with a sheet of Al alloy attached thereto for its form. This image is as shown in FIG. 19. In a case of fastening structure shown in FIG. 19, a hole for bolt is formed for each of flanges of island-shape so as to be used for fastening to the body.

[0204] Dimension of 4 Ti alloy plate to be joined by adhesion with FRP is length of 2 m, width of 50 m and thickness of 10 mm, for example, and three flanges are provided therein, and area of 2 m×50 mm a portion of adhesion after New NMTR treatment for joining by injection molding is secured. In order to form a peripheral wall (for retaining adhesive) with a bottom width of 4 mm and head portion width of 2 mm through joining by injection molding, an injection molding instrument and a metallic mold therefor is prepared. PPS resin “SGX120”as this resin to be injected is injected into the metallic mold to form this peripheral wall, and thickness of the layer of adhesive to be required actually is calculated. A model of a portion of adhesion on the metal side is, for example, as shown in FIG. 18.

[0205] The face of adhesion is of a rectangular form of 199.2 cm (2 m-4 mm×2) and 4.2 cm (50 mm-4 mm×2). For the longer side of about 2 m, coefficient of linear expansion is (0.7 to 0.8)×10.sup.−5K.sup.−1 as the direction is same as GF fiber, substantially same as coefficient of linear expansion of 64 Ti alloy. For the other side of 4.2 cm, coefficient of linear expansion near to coefficient of CF. This width of 4.2 cm is related to width of 4.2 cm on the 64 Ti alloy side. When temperature is lowered by 200° C. from +150° C. to −50° C., FRP side becomes smaller by 0.1×10.sup.−5K.sup.−1×200° C.×4.2 cm=0.0084 cm, being reduced to 4.0916 cm. The other Ti alloy side becomes smaller by 0.8×10.sup.−5K.sup.−1×200° C.×4.2 cm=0.00672 cm, being reduced to 4.1933 cm. As difference of dimension is 4.1933−4.0916=0.1017. As shown in FIGS. 11(a) and 11(b), bottom width of the small triangles at both ends is 0.1017/2=0.0508 cm and height of the small triangle as thickness of the layer of adhesive is 0.5 mm. This corresponds just to such as show in right-lower side of FIGS. 11(a) and 11(b). This is of a level providing no problem at all.

[0206] In such a manner, it can be understood that thickness of a layer of adhesive of 0.5 mm creates no problem only with simulation by thought. Of course, implementation of it is not possible only with knowledge of Experiment Examples 6 and 7, but it is necessary to prepare a model for experiment corresponding to an actually used object and to repeat thermal shock tests. Considering that there was substantially no example using an object in which GFRP and CFRP prepregs are laminated together as in the present invention, specifically experiment with actual objects is necessary. That is, products of GFRP implemented at present called as glass epoxy are used for electric products or in the field of civil engineering and construction. This is an object in which GFRP prepregs are laminated together using thermosetting epoxy resin as matrix resin, thus its producing process is same as in a case of CFRP. However, there are such matters that thickness of fiber or constituency of thermosetting epoxy resin are different from each other, there is a case where tow component epoxy adhesive is used, for example, or mechanical performance or heat resistance ability required for a DFRP product is different. Due to this, GFRP prepreg and CFRP prepreg are dealt with in a same column. If form of fiber is similar and matrix resin same as for CFRP is to be prepared, almost of all raw materials for GFRP commercially available at present cannot be used as they are, thus requiring substantial amount of work, such as developing it by oneself or purchasing from a current producer of CFRP, though being possible.

[0207] With advancement considering that what is possible technically is attained by actually doing so, even if much expense is required therefor. While such intermediate operations are omitted in this experiment example, it is considered that GFRP will come to be able to be dealt with in a similar manner as CFRP and it is not so difficult matter, thus will be attained necessarily. With the present invention, it was decided based on calculation about whether a problem occurs on a portion of adhesion with a metal in a product decided to be possible, for example a composite part shown in FIG. 19 having been subjected to a three thousand cycle thermal shock test, and decided it to be possible. In short, it is assumed that an object of cured adhesive having thickness of layer of cured adhesive of 0.5 mm or so has a sufficient life time.