Abstract: Provided is an ink film recovery method including detaching and removing, from a plastic substrate having an ink film, the ink film by using an ink cleaning agent containing water and at least one selected from an amphoteric surfactant and a cationic surfactant, and then recovering the detached ink film, an ink cleaning agent that can be applied to this ink film recovery method, and an ink film detaching method. Ink films printed on plastic substrates can be easily detached and the detached ink films can be easily recovered using an ink cleaning agent that contains water and at least one selected from an amphoteric surfactant and a cationic surfactant.

Abstract: A novel compound is used as a novel photopolymerization initiator, the novel compound having a molecular structure represented by general formula 1 below [R1 represents an alkyl group having 1 to 10 carbon atoms, R2 represents an alkyl group having 1 to 12 carbon atoms or the like, R3 represents an alkyl group having 1 to 12 carbon atoms or the like, R4 to R7 each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or the like, Y1 represents an alkyl group having 3 to 19 carbon atoms or the like, Y2 represents an organic linking group, X1 represents an ethylene group or the like, X2 and X3 each represent an ethylene group or the like, Y3 represents a single bond or an alkylidene group, and n represents an integer of 1 to 3].

Abstract: A novel compound is used as a novel photopolymerization initiator, the novel compound having a molecular structure represented by general formula 1 below [R1 represents an alkyl group having 1 to 10 carbon atoms, R2 represents an alkyl group having 1 to 12 carbon atoms or the like, R3 represents an alkyl group having 1 to 12 carbon atoms or the like, R4 to R7 each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or the like, Y1 represents an alkyl group having 3 to 19 carbon atoms or the like, Y2 represents an organic linking group, X1 represents an ethylene group or the like, X2 and X3 each represent an ethylene group or the like, Y3 represents a single bond or an alkylidene group, and n represents an integer of 1 to 3].

Abstract: The present invention provides an active energy ray-curable composition exhibiting high curability and having excellent offset printability when used for a printing ink, an active energy ray-curable printing ink having both excellent curability and offset printability, and a printed matter using the same. An active energy ray-curable composition includes a urethane (meth)acrylate resin (A) and a polymerization initiator (B), wherein the urethane (meth)acrylate resin (A) is produced by using an aromatic polyisocyanate (a), a hydroxyl group-containing mono(meth)acrylate (b), and a polyol (c) as essential reaction raw materials so that the ratio [(b?)/(a?)] of the number of moles (b?) of hydroxyl groups contained in the hydroxyl group-containing mono(meth)acrylate (b) to the number of moles (a?) of isocyanate groups contained in the aromatic polyisocyanate (a) is within a range of 0.99 to 0.40, and the urethane (meth)acrylate resin (A) has a (meth)acryloyl group concentration within a range of 1.5 to 4.0 mmol/g.

Abstract: The present invention provides an active energy ray-curable composition exhibiting high curability and having excellent offset printability when used for a printing ink, an active energy ray-curable printing ink having both excellent curability and offset printability, and a printed matter using the same. An active energy ray-curable composition includes a urethane (meth)acrylate resin (A) and a polymerization initiator (B), wherein the urethane (meth)acrylate resin (A) is produced by using an aromatic polyisocyanate (a), a hydroxyl group-containing mono(meth)acrylate (b), and a polyol (c) as essential reaction raw materials so that the ratio [(b?)/(a?)] of the number of moles (b?) of hydroxyl groups contained in the hydroxyl group-containing mono(meth)acrylate (b) to the number of moles (a?) of isocyanate groups contained in the aromatic polyisocyanate (a) is within a range of 0.99 to 0.40, and the urethane (meth)acrylate resin (A) has a (meth)acryloyl group concentration within a range of 1.5 to 4.0 mmol/g.