Patent ID: 11958268
Assignee: NIPPON STEEL CORPORATION
Field: Surface technology, coating (Chemistry)
Classification: CPC B  C | IPC B  C

Claim 6:
7. A method of producing a metal-carbon fiber reinforced plastic material composite,
the metal-carbon fiber reinforced plastic material composite including: a metal member; a carbon fiber reinforced plastic mated al that contains a predetermined matrix resin and a carbon fiber material present in the matrix resin; and one or two layers of coating layers provided between the metal member and the carbon fiber reinforced plastic material, the method comprising:
in the case where the coating layer consists of one layer,
a step of applying a coating material, the coating material containing a predetermined resin as a main component thereof and containing a blocked isocyanate having an isocyanate group protected by a blocking agent, to at least a portion of the metal plate or the metal member and performing drying or baking thereon to form the coating layer with an unreacted isocyanate remaining therein; and
a step of molding the metal plate or the metal member on which the coating layer with the unreacted isocyanate remaining therein is formed and bonding the carbon fiber reinforced plastic material, the carbon fiber reinforced plastic material containing, as the matrix resin, a matrix resin containing a phenoxy resin as a main component thereof and containing an epoxy, group, to an upper layer of the coating layer by thermocompression bonding,
the method comprising:
in the case where the coating layer consists of two layers,
a step of applying a first coating material, the first coating material containing a predetermined resin as a main component thereof and containing a blocked isocyanate having an isocyanate group protected by a blocking agent, to at least a portion of the metal plate or the metal member and performing drying or baking thereon to form the first coating layer with an unreacted isocyanate remaining therein;
a step of applying a second coating material containing an epoxy resin as a main component thereof to at least a portion of the first coating layer with the unreacted isocyanate remaining therein and performing drying or baking thereon to form the second coating layer; and
a step of bonding the carbon fiber reinforced plastic material to at least a portion of the second coating layer by thermocompression bonding, wherein
a dissociation temperature of the blocked isocyanate is lower than a thermocompression bonding temperature in the step of bonding by the thermocompression bonding,
when the dissociation temperature of the blocked isocyanate is set to α [° C.] and a maximum attained temperature in the case where the coating layer consists of one layer and in the step of forming the first coating layer in the case where the coating layer consists of two layers is set to β [° C.], the maximum attained temperature β is set to a temperature satisfying 80° C.≤β≤250° C. and α≤β to make the unreacted blocked isocyanate remain in the formed coating layer and the formed first coating layer,
a maximum attained temperature in the step of forming the second coating layer in the case where the coating layer consists of two layers is set to equal to or more than the dissociation temperature of the blocked isocyanate and less than the thermocompression bonding temperature, and
as a thermocompression bonding condition in the step of bonding by the thermocompression bonding, the thermocompression bonding temperature falls within a range of 100° C. to 400° C., a pressure is 3 MPa or more, and a thermocompression bonding time is three minutes or more.