The invention discloses a preparation method of an OCA (Optical Clear
Adhesive). The preparation method comprises the following steps: step (1), weighing the following components in percentage by
mass: 90 to 99 percent of an acrylic
prepolymer, 0 to 10 percent of an acrylic
monomer, 0.1 to 0.5 percent of a cross-linking agent, 0.1 to 0.5 percent of a
photoinitiator and 0.1 to 1 percent of a chaintransfer agent; step (2), putting and stirring the acrylic
prepolymer, the acrylic
monomer, the cross-linking agent, the
photoinitiator and the
chain transfer agent in a container, and carrying out primary curing under an
ultraviolet lamp after introducing
nitrogen, thus obtaining a
prepolymer; step (3), defoaming the prepolymer obtained in step (2),
coating a PET (
Polyethylene Terephthalate) lining sheet, and carrying out secondary curing under the
ultraviolet lamp, thus obtaining the OCA. According to the preparation method disclosed by the invention, incompletely cured OCA in low gel fraction can be obtained through once
UV curing, and gaps between adhered objects can be effectively wetted and filled, so that the range difference of
printing ink can be filled; secondary curing is carried out after adhesion, the
dissipation factor value is increased, and a product is more partial to an
elastomer, so that good
aging resistance and good reworking performance are obtained.