JP-2026075607-A - Anchor coating compositions, printed materials, and packaging materials

Abstract

【assignment】 The present invention provides a printed material having electron beam-curable ink printed on a plastic film, which exhibits excellent adhesion to printed materials and is applicable to food packaging materials, and an anchor coat composition applicable thereto. [Solution] An anchor coat composition for printed materials, which is printed on a resin substrate in the order of anchor coat composition and electron beam curable ink, wherein the anchor coat composition contains a urethane resin (A) and an aqueous medium (B), and a printed material formed in the order of resin substrate, anchor coat layer and electron beam curable ink layer, wherein the anchor coat layer is a layer on which the anchor coat composition containing urethane resin (A) and aqueous medium (B) has been printed. Printed material and packaging material [Selected Figure] None

Inventors

• 大坪 拓哉
• 清水 智章
• 小代 康敬

Assignees

• ＤＩＣグラフィックス株式会社

Dates

Publication Date

20260508

Application Date

20251014

Priority Date

20241022

Claims (9)

1. An anchor coat composition for printed materials, wherein the anchor coat composition and electron beam-curable ink are printed on a resin substrate in that order, the anchor coat composition comprising a urethane resin (A) and an aqueous medium (B).
2. The anchor coat composition according to claim 1, wherein the urethane resin (A) is a urethane resin that is a reaction product of a polyol containing a polyether polyol and a polyisocyanate.
3. The anchor coat composition according to claim 2, wherein the urethane resin (A) does not contain polyester polyol as the polyol.
4. The anchor coat composition according to claim 1 or 2, wherein the aqueous medium (B) is water alone, or a mixture of water and an organic solvent miscible with water.
5. A printed material formed in the order of a resin substrate, an anchor coat layer, and an electron beam-curable ink layer, wherein the anchor coat layer is a layer printed with an anchor coat composition containing a urethane resin (A) and an aqueous medium (B).
6. The printed material according to claim 5, wherein the urethane resin (A) is a urethane resin that is a reaction product of a polyol containing a polyether polyol and a polyisocyanate.
7. The printed material according to claim 5 or 6, wherein the electron beam-curable ink layer is a printed layer printed by a lithographic offset printing method or a flexographic printing method.
8. A laminate using the printed material described in claim 5.
9. A packaging material using the printed material described in claim 5.

Description

This invention relates to an anchor coat composition suitable for printed materials using electron beam-curable inks, and to printed materials and packaging materials using the same. UV-curing inks and electron beam-curing inks, commonly referred to as active energy ray-curing inks, are both inks that are cured by irradiation with active energy and are environmentally friendly inks that do not require solvents. However, because UV-curing inks require a photoinitiator, there is a concern that when printed materials are applied to food packaging, for example, the low-molecular-weight photoinitiator may migrate to the food packaging. On the other hand, electron beam curing inks cure using electron beams, thus eliminating the need for photopolymerization initiators and reducing migration concerns. However, since electron beam irradiation itself is not widely used in Japan, much further research is needed before electron beam curing inks can be used to industrially supply food packaging materials and other products. When printing electron beam-curable inks onto plastic films used as base materials for food packaging, there is a problem in that the adhesion of the electron beam-curable ink to the plastic film tends to be insufficient. To address this, for example, Patent Document 1 discloses a printed material in which an electron beam-curable ink is offset printed onto a printing film in which a coating agent containing a polyester resin having hydroxyl groups and a compound having isocyanate groups, with an organic solvent as the solvent, is coated onto the plastic film as an anchor coat. Furthermore, Patent Document 2 discloses a printed structure flexographically printed on a plastic film in the following order: an anchor coating agent, a colored ink including process colors and spot colors, and a white ink, characterized in that the anchor coating agent and the white ink use an aqueous polyurethane resin as a binder, and the colored ink uses an aqueous acrylic resin or an ultraviolet/electron beam curable resin as a binder. However, since the coating agent disclosed in Patent Document 1 uses an organic solvent, the resulting food packaging material cannot be said to be completely environmentally friendly, even if an electron beam curable ink that does not require a solvent is used. Furthermore, the specific embodiment disclosed in Patent Document 2 is a printed structure produced by using an aqueous flexographic ink anchor varnish (aqueous polyurethane resin) and printing while irradiating it with an ultraviolet-curable flexographic ink using a metal halide lamp and a high-pressure mercury lamp (see Patent Document 2, Example 6), which cannot be considered sufficient disclosure for those skilled in the art who use electron beam curable inks. Japanese Patent Publication No. 2023-49235Japanese Patent Publication No. 2005-225083 In this specification, "~" means a value greater than or equal to the value before the "~" notation, and a value less than or equal to the value after the "~" notation. (Anchor coat composition) The anchor coating composition of the present invention contains a urethane resin (A) and an aqueous medium (B). (urethane resin) In the present invention, the urethane resin (A) is not particularly limited as long as it is a urethane resin that disperses or dissolves well in an aqueous medium (B). However, as a particularly good example, a polyol (a1) containing an acid group-containing polyol (a1-1) and a polyether polyol (a1-2) other than the polyol (a1-1), and a polyisocyanate (a2) can be used. Examples of the polyol having an acid group (a1-1) include polyols having a carboxyl group and polyols having a sulfonic acid group. Examples of polyols having carboxyl groups include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid. Among these, 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid are preferred due to their good dispersion stability. Furthermore, polyester polyols having carboxyl groups, obtained by reacting the aforementioned polyols having carboxyl groups with various polycarboxylic acids, can also be used. These polyols having carboxyl groups can be used individually or in combination of two or more. Examples of polyols having sulfonic acid groups include polyester polyols obtained by reacting dicarboxylic acids such as 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, and 5-(4-sulfophenoxy)isophthalic acid, or their salts, with low molecular weight polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and neopentyl glycol. These polyols having sulfonic acid groups can be used individually or in combination of two or more. The polyol (a1-1) having the acid group is preferably used in a range where the acid value of the urethane resin (A) is 10 to 50, and more preferably in a range of 10 to 35. The acid value as used in this invention is a theoretical value calculat