Patent ID: 8053493

Claim:
An ink having a viscosity of 20˜80 cP and a volumetric shrinkage of 10˜30%, comprising: (a) a first monomer, which is an acrylic monomer having a viscosity of 10˜15 cP and having one or two polymerizable functional groups; and (b) a second monomer mixture, which is an acrylate monomer mixture comprising a low-viscosity monomer having a viscosity of 30˜170 cP and a high-viscosity monomer having a viscosity of 10,000 cP or more, wherein each of the monomer comprised in the mixture has at least three polymerizable functional groups, in the presence of 0˜20 wt % of a solvent, wherein the ink can form a convex portion due to its surface tension controlled to 20˜40 mN/m, so as to compensate for its volumetric shrinkage, wherein the viscosity and the surface tension are measured at 25° C., and wherein the first monomer is included in an amount of 30 wt % or more based on the ink, and the second monomer is included in an amount of 3˜50 wt % based on the ink, wherein the high-viscosity monomer includes six polymerizable functional groups in an amount of 4-9 wt % based on the ink.