Ink composition, inkjet recording method, and printed article

1. An ink composition comprising: (a) a polymer having a siloxane structure and a polymerizable group on a side chain thereof; (b) a polymerizable compound; (c) a photopolymerization initiator; and (d) a monofunctional monomer, the siloxane structure being obtained by polymerizing a compound represented by the following Formula (A):

wherein in Formula (A), R 1 is a straight chain or branched alkylene group having 2 to 6 carbon atoms or a divalent connecting group represented by the following Formula (B); x 1 , x 2 and x 3 are integers having a relationship such that the sum of x 1 , x 2 and x 3 , (x 1 +x 2 +x 3 ), is from 1 to 100; y 1 is an integer of from 1 to 10; X is a single bond or a divalent group represented by the following Formula (C); Y represents a monovalent group represented by any of Formulae (D) to (F); and Z represents a monovalent group represented by the following Formula (G);

wherein in Formula (B), R 2 represents a hydrogen atom or a methyl group, and n represents an integer of from 1 to 50;

—Z 1 —CO—NH—R 3 —NH—CO—  Formula (C)

wherein in Formula (C), Z 1 represents an oxygen atom, a sulfur atom, or NR 4 ; R 4 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Z 1 is bonded to R 1 in Formula (A); and R 3 represents a divalent aliphatic or alicyclic group having 6 to 10 carbon atoms;

wherein in Formulae (D) to (F), R 5 represents a hydrogen atom or a straight chain or branched alkyl group having 1 to 6 carbon atoms, R 6 represents a straight chain or branched alkylene group having 2 to 10 carbon atoms, and R 7 represents a straight chain or branched alkylene group having 1 to 6 carbon atoms;

wherein in Formula (G), z 1 is an integer of from 3 to 100, and

wherein the content of the polymer (a) is, with respect to the total solid content of the ink composition, from 0.1% to 10% by mass.

2. The ink composition according to claim 1 , wherein the polymerizable group of the polymer (a) on a side chain thereof is a radical polymerizable group.

3. The ink composition according to claim 1 , wherein the polymerizable group of the polymer (a) on a side chain thereof is a cationic polymerizable group.

4. The ink composition according to claim 1 , wherein the polymer (a) further comprises a monomer capable of forming a homopolymer having a glass transition temperature of 50° C. or higher as a copolymerized component, wherein the monomer capable of forming a homopolymer having a glass transition temperature of 50° C. or higher is at least one selected from the group consisting of isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butyl (meth)acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenethyl (meth)acrylate, methyl 2-chloro(meth)acrylate, ethyl α-chloroacrylate, (meth)acrylamide, N-isopropyl acrylamide, and dicylopentanyl (meth)acrylate.

5. The ink composition according to claim 1 , wherein the polymerizable compound (b) is a radical polymerizable compound.

6. The ink composition according to claim 1 , wherein the polymerizable compound (b) is a cationic polymerizable compound.

7. An inkjet recording composition comprising the ink composition of claim 1 .

8. An inkjet recording method comprising:

ejecting on a recordable medium the ink composition of claim 1 using an inkjet recording apparatus; and

curing the ink composition by irradiation of an actinic radiation ray to the ejected ink composition.

9. A printed article recorded by the inkjet recording method according to claim 8 .

10. The ink composition according to claim 1 , wherein the monofunctional monomer (d) is N-vinyl caprolactam.