Actinic radiation-curing type ink composition, inkjet recording method, decorative sheet, decorative sheet molded product, process for producing in-mold molded article, and in-mold molded article

1. An actinic radiation-curing ink composition comprising:

(Component A) a monofunctional radically polymerizable monomer; and

(Component B) a polyfunctional acrylate oligomer having a glass transition temperature of no greater than 20° C. and having an acrylate equivalent of at least 300 g/eq,

(Component E) a resin having a urethane bond in a main chain and having an ethylenically unsaturated group and a polysiloxane structure in a side chain and/or at a terminal,

Component A comprising (Component A-1) an N-vinyl compound and (Component A-2) an acrylamide derivative,

Component A having a content of at least 70 mass % of the entire ink composition, and

Component A-1 having a content of at least 18 mass % of the entire ink composition,

wherein when the content of Component A-2 in 100 parts by mass of the ink composition is (a-2) (parts by mass) and the content of Component B is (b) (parts by mass), (a-2):(b) mass ratio is 30:1 to 1:1,

wherein Component A-1 is a compound represented by Formula (A) below

wherein, in Formula (A), n denotes an integer of 2 to 6,

wherein Component A-2 is a compound represented by Formula (a-2-1) below

wherein, in Formula (a-2-1), R a1 and R a2 independently denote a hydrogen atom or an alkyl group having 1 to 12 carbons, R a1 and R a2 may be bonded to form an alkylene group having 4 to 8 carbons, a hydrogen atom contained in the alkyl group or the alkylene group may be replaced by a hydroxy group, a methylene group contained in the alkyl group or the alkylene group may be replaced by an oxygen atom, a sulfur atom, —CO—, or —NR a3 —, and R a3 denotes a hydrogen atom or an alkyl group having 1 to 6 carbons.

2. The actinic radiation-curing ink composition according to claim 1 , wherein Component A-2 has a content of 5 to 50 mass % of the entire ink composition.

3. The actinic radiation-curing ink composition according to claim 1 , wherein Component B has a content of 0.1 to 10 mass % of the entire ink composition.

4. The actinic radiation-curing ink composition according to claim 1 , wherein it comprises (Component C) a polymerization initiator, Component C comprising (Component C-1) a thioxanthone compound.

5. The actinic radiation-curing ink composition according to claim 1 , wherein Component B is a difunctional acrylate oligomer.

6. The actinic radiation-curing ink composition according to claim 1 , wherein Component B has an isophorone structure.

7. The actinic radiation-curing ink composition according to claim 1 , wherein it further comprises (Component D) a difunctional monomer having a viscosity at 25° C. of no greater than 15 mPa·sec.

8. The actinic radiation-curing ink composition according to claim 7 , wherein Component D is represented by Formula (d-1) below,

A-B-A′  (d-1)

wherein in Formula (d-1), A denotes a group selected from the group consisting of (A-1) to (A-3) below, A′ denotes a group selected from the group consisting of (A′-1) to (A′-3) below, and B denotes a divalent linking group represented by Formula (B-1) or (B-2) below,

wherein in Formula (A-1) R 11 denotes a hydrogen atom or a methyl group, in Formula (B-1) R 12 denotes a saturated hydrocarbon group having 2 to 12 carbons, in Formula (B-2) one of R 13 and R 14 denotes a hydrogen atom, the other denotes a hydrogen atom or a methyl group, and n denotes an integer of 2 to 10, in Formula (A′-1) R 15 denotes a hydrogen atom or a methyl group, * denotes the position of bonding between A and B, and ** denotes the position of bonding between B and A′.

9. The actinic radiation-curing ink composition according to claim 1 , wherein Component A comprises (Component A-3) a compound represented by Formula (a-3) below,

wherein in Formula (a-3), R 31 denotes a hydrogen atom or a methyl group, R 32 denotes a methyl group or an ethyl group, and m denotes an integer of 1 to 5.

10. The actinic radiation-curing ink composition according to claim 1 , wherein it is for use in inkjet recording.

11. An inkjet recording method comprising:

(a 1 ) a step of discharging an ink composition onto a recording medium; and

(b 1 ) a step of irradiating the discharged ink composition with actinic radiation to thus cure the ink composition,

the ink composition being the actinic radiation-curing type ink composition according to claim 1 .

12. The inkjet recording method according to claim 11 , wherein the actinic radiation employs a light-emitting diode as a light source.

13. A decorative sheet comprising a cured image layer of the actinic radiation-curing type ink composition according to claim 1 provided above a resin sheet.

14. A decorative sheet molded product obtained by vacuum forming, pressure forming, or vacuum/pressure forming of the decorative sheet according to claim 13 .

15. The decorative sheet molded product according to claim 13 , wherein it is further subjected to hole making by means of trimming subsequent to the vacuum forming, pressure forming, or vacuum/pressure forming.

16. A process for producing an in-mold molded article, comprising:

a step of placing the decorative sheet molded product according to claim 14 on an inner wall of a hollow part formed from a plurality of molds; and

a step of injecting a molten resin into the hollow part via a gate.

17. An in-mold molded article obtained by the production process according to claim 16 .

18. The actinic radiation-curing ink composition according to claim 1 , wherein the Component A-2 is at least one component selected from the group consisting of N, N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, and acryloylmorpholine.

19. The actinic radiation-curing ink composition according to claim 1 , wherein the (a-2):(b) (mass ratio) is 10:1 to 2:1.

20. The actinic radiation-curing ink composition according to claim 2 , wherein the Component A-2 has a content of 12 to 25 mass % of the entire ink composition.