Composite material in which steel sheet and plastic layer having functional group introduced therein are laminated, and method for producing same

A composite material comprising:

• a plastic layer having a first surface, wherein polar functional groups are introduced onto the first surface of the plastic layer, and the polar functional group comprises:
• one or more of a hydroxy group (—OH), a carboxy group (—COOH), a carbonyl group (—CO—), an amino group (—NH2), a hydroperoxy group (—OOH), a peroxy group (—OO—), a thiol group (—SH), and an isocyanate group (—NCO);
• and
• a first steel sheet laminated on the first surface of the plastic layer, wherein the first steel sheet includes a surface in contact with the first surface of the plastic layer, and plastic particles are dispersed in the surface of the first steel sheet, and
• wherein the plastic particles are formed of a homogeneous resin,
• wherein the first steel sheet includes a plated layer formed on the surface of the first steel sheet,
• the plastic particles are dispersed in a surface of the plated layer, and
• the surface of the plated layer has an arithmetic mean roughness (Ra) in a range of 0.01 μm to 5 μm.