Polymerizable composition

A polymerizable composition comprising

• (A) a resin selected from the group consisting of a polyamide resin which is soluble or swells in water or aqueous alkali solutions and a polyester resin which is soluble or swells in water or aqueous alkali solutions,
• (B) an infrared absorber,
• (C) a radical polymerization initiator, and
• (D) a radical-polymerizable compound,
• wherein the resin (A) has carboxy groups in side chains thereof;
• and
• wherein the resin (A) has bonds represented by one of the following formulae (II) to (V) in side chains thereof:
• wherein R5 to R7 each independently represents a hydrogen atom or a monovalent organic group;
• X represents an oxygen atom, a sulfur atom, or —N(R17)—, in which R17 represents a hydrogen atom or a monovalent organic group;
• R8 to R12 each independently represents a hydrogen atom or a monovalent organic group;
• Y represents an oxygen atom, a sulfur atom, or —N(R18)—, in which R18 represents a hydrogen atom or a monovalent organic group;
• R13 to R15 each independently represents a hydrogen atom or a monovalent organic group;
• Z represents an oxygen atom, a sulfur atom, —N(R19)—, or optionally substituted phenylene, in which R19 represents a hydrogen atom or a monovalent organic group;
• R16 represents a hydrogen atom or a monovalent organic group;
• and A represents an optionally substituted alkylene or optionally substituted phenylene group.