Surface coating agent and surface coating method for elastic molding die

A surface coating method for an elastic molding die comprising the steps of:

• contacting a surface of an elastic molding die with an aqueous solution of sulfuric acid for a period of time sufficient to form an acid treated surface;
• washing said acid treated surface with water to form a washed surface;
• drying said washed surface to form a dried surface;
• and
• coating said dried surface with a polyurethane surface coating agent by applying a solution of a polyurethane surface coating agent to said dried surface and then drying said applied solution, said polyurethane surface coating agent having been obtained by reacting a polyol with an aromatic polyisocyanate.

A surface coating method for an elastic molding die comprising the steps of:

• contacting a surface of an elastic molding die with an aqueous solution of sulfuric acid for a period of time sufficient to form an acid treated surface;
• washing said acid treated surface with water to form a washed surface;
• drying said washed surface to form a dried surface;
• coating a primer on said dried surface to form a primed surface, said primer being selected from the group consisting of:
• a reaction product of a hydroxyl-terminated polydiene and a polyisocyanate, a mixture of an elastomer and a polyurethane, a cyanoacrylate compound, and an epoxy compound;
• and
• coating said primed surface with a polyurethane surface coating agent by applying a solution of a polyurethane surface coating agent to said primed surface and then drying said applied solution, said polyurethane surface coating agent having been obtained by reacting a polyol with an aromatic polyisocyanate.