The invention discloses a toughened alpha-
cyanoacrylate adhesive and a preparation method thereof. The
adhesive comprises the following components: alpha-
cyanoacrylate, a
polyurethane prepolymer which is 20 to 60 percent based on the
mass of the alpha-
cyanoacrylate, an anionic
polymerization inhibitor which is 50 to 250ppm based on the
mass of the alpha-cyanoacrylate, a
radical polymerization inhibitor which is 100 to 2,000 ppm based on the
mass of the alpha-cyanoacrylate, a thickener, a
heat resistant agent, a reinforce, a
pigment, a spice and the like. The method for preparing the
adhesive comprises: adding the
polyurethane prepolymer which is 20 to 60 percent based on the mass of the alpha-cyanoacrylate and the alpha-cyanoacrylate into a three-necked flask, mixing and stirring the
polyurethane prepolymer and the alpha-cyanoacrylate for 1 hour at 50 to 60 DEG C and obtaining an alpha-cyanoacrylate and polyurethane prepolymer complex; and filling the alpha-cyanoacrylate and polyurethane prepolymer complex, the
radical polymerization inhibitor and the anionic
polymerization inhibitor into the three-necked flask, and mixing and stirring the materials in the three-necked flask till the mixture is uniform. The anionic
polymerization inhibitor is 50 to 250ppm based on the mass of the alpha-cyanoacrylate and the
radical polymerization inhibitor is 100 to 2,000 ppm based on the mass of the alpha-cyanoacrylate.