Ink composition, inkjet recording method using the same, and printed material
An ink composition containing (a) a polymerizable compound, (b) a pigment, and (c) a graft polymer having, as a polymerization unit, a polymerizable oligomer having an ethylenically unsaturated double bond at least at a terminal thereof. The graft polymer (c) preferably contains, as a polymerization unit, a polymerizable oligomer having a number-average molecular weight of 1000 to 20000 and having a (meth)acryloyl group at a terminal thereof.
1 . An ink composition comprising (a) a polymerizable compound, (b) a pigment, and (c) a graft polymer containing, as a polymerization unit, a polymerizable oligomer having an ethylenically unsaturated double bond at least at a terminal thereof.
2 . The ink composition according to claim 1 , wherein the polymerizable oligomer is an oligomer having a (meth)acryloyl group at a terminal thereof.
3 . The ink composition according to claim 1 , wherein the polymerizable oligomer is an oligomer having a number-average molecular weight of 1000 to 20000.
4 . The ink composition according to claim 1 , wherein the polymerizable oligomer is a homopolymer or copolymer of at least one monomer selected from the group consisting of alkyl(meth)acrylates, styrenes, acrylonitril, vinyl acetate, and butadiene.
5 . The ink composition according to claim 1 , wherein the polymerizable oligomer is a homopolymer or copolymer of at least one monomer selected from the group consisting of alkyl(meth)acrylates and styrenes.
6 . The ink composition according to claim 1 , wherein the polymerizable oligomer is a polymer in which a (meth)acryloyl group is bound to one terminal of polystyrene, polymethyl(meth)acrylate, poly-n-butyl(meth)acrylate, or poly-i-butyl(meth)acrylate.
7 . The ink composition according to claim 1 , wherein the polymerizable oligomer is represented by formula (1):
wherein in formula (1), R 11 and R 13 each independently represent a hydrogen atom or a methyl group; R 12 represents a C1 to C12 alkylene group which may have a substituent and may have an ester bond, an ether bond, or an amide bond at a terminal; Y represents a phenyl group, a phenyl group having a C1 to C4 alkyl group, or —COOR 14 in which R 14 represents a C1 to C6 alkyl group, a phenyl group, or a C7 to C10 aryl alkyl group; and q represents 20 to 200.
8 . The ink composition according to claim 1 , wherein the graft polymer further contains, as a polymerization unit, a monomer having a nitrogen-containing group and an ethylenically unsaturated double bond.
9 . The ink composition according to claim 8 , wherein the monomer having a nitrogen-containing group and an ethylenically unsaturated double bond is represented by formula (I):
wherein in formula (I), R 1 represents a hydrogen atom or a methyl group; R 2 represents a C1 to C12 alkylene group; X 1 represents —N(R 3 )(R 4 ), —R 5 —N(R 6 )(R 7 ), or a basic nitrogen-containing heterocyclic group; R 3 , R 4 , R 6 and R 7 each independently represent a hydrogen atom, a C1 to C18 alkyl group, or a C6 to C18 aryl group; R 5 represents a C1 to C12 alkylene group; and m and n each independently represent 1 or 0.
10 . The ink composition according to claim 9 , wherein X 1 represents a a pyridyl group, a piperidino group, a pyrrolidyl group, a pyrrolidino group, an imidazolino group, or a morpholino group.
11 . The ink composition according to claim 1 , further comprising (d) a photopolymerization initiator.
12 . The ink composition according to claim 11 , wherein the polymerizable compound (a) is a radical-polymerizable compound, and the photopolymerization initiator (d) is a photoradical generator.
13 . The ink composition according to claim 11 , wherein the polymerizable compound (a) is a cation-polymerizable compound, and the photopolymerization initiator (d) is a photoacid generator.
14 . The ink composition according to claim 1 , wherein an amount of the polymerizable oligomer in the graft polymer is 20 to 99% by weight.
15 . The ink composition according to claim 8 , wherein an amount of the monomer having a nitrogen-containing group and an ethylenically unsaturated double bond in the graft polymer is 20 to 99% by weight.
16 . An inkjet ink composition comprising the ink composition of claim 1 .
17 . An inkjet recording method comprising:
depositing the ink composition of claim 16 onto a recording medium with an inkjet printer; and
curing the deposited ink composition by irradiation with active radiation.
18 . A printed material produced by a method comprising:
depositing the ink composition of claim 16 on a recording medium with an inkjet printer; and
curing the ink composition by irradiation with active radiation.