Patent ID: 8277944

Claim:
A primer composition for application to concrete, the primer composition comprising a resin composition containing (A) a urethane (meth)acrylate resin (A-1) obtained by reacting a hydroxyalkyl (meth)acrylate (A-1-3) with a terminal-isocyanate-group-containing urethane prepolymer obtained by reacting polytetramethylene glycol (A-1-1) having a number-average molecular weight of 650 to 2,000 with a polyisocyanate component (A-1-2), or a mixture of the urethane (meth)acrylate resin (A-1) and a urethane (meth)acrylate resin (A-2) obtained by reacting a hydroxyalkyl (meth)acrylate (A-2-3) with a terminal-isocyanate-group-containing urethane prepolymer obtained by reacting a polyether polyol (A-2-1) selected from polyoxypropylene diol and polyoxyethylene diol and having a number-average molecular weight of 650 to 2,000 with a polyisocyanate component (A-2-2); (B) a polymerizable unsaturated monomer containing a hydroxyalkyl (meth)acrylate (B-1) and a polymerizable unsaturated monomer (B-2) other than the (A-1), the (A-2), and the (B-1); (C) a curing accelerator; (D) a paraffin wax; and (E) a cobalt organic acid salt, wherein a molar ratio of the (B)/the (A) is 4 to 20, a mass ratio of the (A-1)/the (A-2) is 100/0 to 10/90, and a mass ratio of the (B-1)/the (B-2) is 35/65 to 5/95.