US-12617954-B2 - Coating agent for film, laminate, and method for manufacturing printed article

Abstract

An object of the present invention is to provide a coating agent for a film that can exhibit sufficient adhesion to a film even when the active energy ray-curable ink is used. The present invention provides a coating agent for a film including a compound (a) having two or more (meth)acryloyl groups and an isocyanate group.

Inventors

• Yuichi Tsuji
• Shiro Kobayashi
• Takejiro Inoue

Assignees

• TORAY INDUSTRIES, INC.

Dates

Publication Date

20260505

Application Date

20210331

Priority Date

20200331

Claims (18)

1. 1 . A coating agent for a film comprising a compound (a) having two or more (meth)acryloyl groups and an isocyanate group; wherein the compound (a) is contained in an amount of 70 mass % or more and 100 mass % or less based on the total mass of the coating agent; and wherein an acrylic equivalent, calculated based on a total of (meth)acryloyl groups in the entire coating agent, of the coating agent is 100 g/eq or more and 450 g/eq or less.
2. 2 . The coating agent for a film according to claim 1 , wherein the coating agent for a film is an active energy ray-curable anchor coating agent.
3. 3 . The coating agent for a film according to claim 1 , wherein an isocyanate content of the coating agent is 2 mass % or more and 10 mass % or less.
4. 4 . The coating agent for a film according to claim 1 , wherein the compound (a) has a urethane bond.
5. 5 . The coating agent for a film according to claim 1 , wherein a weight-average molecular weight of the compound (a) is 1,000 or more and 5,000 or less.
6. 6 . The coating agent for a film according to claim 1 , wherein the compound (a) has a structure obtained by reacting (meth)acrylate having a hydroxyl group, a polyol compound, and a polyisocyanate compound, and in the compound (a), a content of the isocyanate group is 0.9 mol or more and 2.2 mol or less with respect to 1 mol of the hydroxyl group.
7. 7 . The coating agent for a film according to claim 6 , wherein the polyol compound is polyester polyol.
8. 8 . The coating agent for a film according to claim 1 , further comprising a urethane compound (b).
9. 9 . The coating agent for a film according to claim 8 , wherein the compound (b) has a (meth)acryloyl group.
10. 10 . The coating agent for a film according to claim 1 , wherein a viscosity of the coating agent at 25° C. and a rotation speed of 0.5 rpm is 30 Pa·s or more and 200 Pa's or less.
11. 11 . A laminate comprising a cured layer of the coating agent for a film described in claim 1 on at least one surface of the film.
12. 12 . The laminate according to claim 11 , wherein an area ratio of a carbon-carbon double bond/a carbonyl group in the cured layer by Raman spectrometry measurement is 0.5 or more and 2.5 or less.
13. 13 . A method for manufacturing a printed article, the method comprising a step of transferring the coating agent for a film described in claim 1 and an active energy ray-curable ink to a film and then irradiating the film with an active energy ray.
14. 14 . The method for manufacturing a printed article according to claim 13 , wherein the active energy ray-curable ink contains a compound (e) having an ethylenically unsaturated group and having at least one functional group selected from the group consisting of an amino group, a hydroxyl group, and an acidic group.
15. 15 . The method for manufacturing a printed article according to claim 13 , wherein the active energy ray-curable ink includes a plurality of colors including an active energy ray-curable white ink, and in the step of transferring the active energy ray-curable ink to the film, the active energy ray-curable white ink is first transferred.
16. 16 . The method for manufacturing a printed article according to claim 13 , wherein the coating agent for a film is transferred to the film in a pattern.
17. 17 . The coating agent for a film according to claim 1 , wherein the acrylic equivalent is 200 g/eq or more and 350 g/eq or less.
18. 18 . The coating agent for a film according to claim 17 , wherein an isocyanate content of the coating agent is 2 mass % or more and 10 mass % or less.

Description

TECHNICAL FIELD The present invention relates to a coating agent for a film, a laminate, and a method for manufacturing a printed article. BACKGROUND ART As the global population increases, demand for flexible packaging, which is mainly used for packaging food and daily necessities, is expected to continue to grow. According to gravure printing, which is currently the mainstream in flexible packaging printing, printed articles with vivid appearance can be obtained. On the other hand, since the gravure printing uses an ink containing a large amount of solvents, a large amount of energy is required for drying an ink solvent and an exhaust treatment, and an environmental load is large. Furthermore, in the flexible packaging printing industry, the needs of the market have changed from mass production and mass consumption in the related art to small lots, various products, and short delivery, and therefore plate margins and plate making margins are expensive. Therefore, the production cost of gravure printing, which is good at large-lot printing, has been increasing. Therefore, in recent years, attempts have been made to perform flexible packaging printing using lithographic printing, which is inexpensive in terms of plate margins and plate making margins, is suitable for small-lot, short-delivery printing, and is superior in terms of cost (refer to Patent Document 1). The lithographic printing is a printing system widely used as a system capable of inexpensively supplying a large volume of printed article at high speed. In recent years, there is a request for the reduction of volatile components contained in lithographic printing inks in addressing the environmental issues. For this reason, the use of ink which is free from volatile components and is instantaneously curable with an active energy ray irradiation, is in progress (refer to Patent Document 2). In the flexible packaging printing, since the printing is performed by a roll-to-roll method, quick drying property of the ink is important. Active energy ray-curable lithographic printing using active energy ray-curable ink not only has environmental advantages, but also saves energy and has high productivity because it does not require a drying step. PRIOR ART DOCUMENT Patent Documents Patent Document 1: Japanese Patent Laid-open Publication No. 2004-358788Patent Document 2: Japanese Patent Laid-open Publication No. 2017-132895 SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, in general, the active energy ray-curable ink has low adhesion to a film. Further, in the active energy ray-curable lithographic printing, adhesion of ink to a film is insufficient as compared with gravure printing, and an applicable film is also limited. Therefore, an object of the present invention is to provide a coating agent for a film that can exhibit sufficient adhesion to a film even when the active energy ray-curable ink is used. Solutions to the Problems The present invention provides a coating agent for a film including a compound (a) having two or more (meth)acryloyl groups and an isocyanate group. The present invention also provides a laminate including a cured layer of the coating agent for a film of the present invention on at least one surface of a film. The present invention also provides a method for manufacturing a printed article, the method including a step of transferring the coating agent for a film of the present invention and an active energy ray-curable ink to a film and then irradiating the film with an active energy ray. Effects of the Invention The coating agent for a film according to the present invention can improve adhesion of an active energy ray-curable ink to a film. EMBODIMENTS OF THE INVENTION Hereinafter, the present invention will be specifically described. In the present invention, “or more” means the same as or more than the numerical value indicated therein. In addition, “or less” means the same as or less than the numerical value indicated therein. In addition, “(meth)acrylate” is a generic name including acrylate and methacrylate, and a “(meth)acryloyl group” is a generic name including an acryloyl group and a methacryloyl group. The coating agent for a film (hereinafter, may be referred to as a “coating agent”) of the present invention contains a compound (a) having two or more (meth)acryloyl groups and an isocyanate group. Since the compound (a) has two or more (meth)acryloyl groups, the compound (a) is radically polymerized by irradiation with an active energy ray. Thus, the coating agent can be cured to form a film. In addition, since the compound (a) has two or more (meth)acryloyl groups, by irradiation with an active energy ray, the (meth)acrylate contained in the active energy ray-curable ink transferred onto the coating agent according to the present invention and the compound (a) undergo a crosslinking reaction, and adhesion between the coating agent and the active energy ray-curable ink can be improved. The