Patent ID: 8901200

Claim:
A radiation-curable ink composition, comprising: an acrylate monomer, of which homopolymer has a glass transition temperature of not higher than 0° C., in an amount of 20% by mass or more and 65% by mass or less based on the total amount of reaction components; a monofunctional acrylate having an alicyclic structure, wherein the monofunctional acrylate having an alicyclic structure is in an amount of 20% by mass or more and 65% by mass or less based on the total amount of the reaction components; a multifunctional acrylate having an alicyclic structure, wherein the multifunctional acrylate having an alicyclic structure is in an amount of more than 1% by mass and 20% by mass or less based on the total amount of the reaction components; and a photopolymerization initiator; wherein: the ink composition has a viscosity at 20° C. in the range of about 10 mPa·s to about 40 mPa·s and a surface tension at 20° C. in the range of about 20 mN/m and about 30 mN/m; and the acrylate monomer is selected from the group consisting of long-chain alkyl acrylate, (poly)ethylene oxide, (poly)propylene oxide adduct of monofunctional acrylate, and modifications thereof.