JP4330566B2 - Active energy ray-curable overprint varnish composition and use thereof - Google Patents

Description

  The present invention relates to an active energy ray-curable overprint varnish composition and use thereof. More specifically, an active energy ray-curable overprint varnish composition used for improving gloss of printed matter in which a water-based printing ink composition is printed on a paper product such as a carton or paper bag, and protecting the printed matter, Further, the present invention relates to a paper product coated with the active energy ray-curable overprint varnish composition.

  Conventionally, an overprint varnish composition has been applied after printing in order to improve the gloss of the printed material and protect the film of the printed material. In particular, active energy ray-curable overprint varnish compositions are widely used because of their excellent film strength.

  For example, in the use of paper products such as paper containers such as cartons and paper bags, a water-based printing ink composition and a water-based anchor varnish are sequentially printed and coated on a paper substrate, and then contain a photopolymerizable compound and a photopolymerization initiator. A technique of applying an active energy ray-curable overprint varnish composition and curing with an active energy ray is used.

  In an active energy ray-curable overprint varnish composition containing a photopolymerizable compound and a photopolymerization initiator, an intramolecular bond cleavage photopolymerization initiator such as benzoin or intermolecular hydrogen such as benzophenone is used as the photopolymerization initiator. A pull-out photopolymerization initiator is used (see, for example, Patent Document 1).

  Among the overprint varnish compositions, a composition using an intramolecular bond cleavage photopolymerization initiator such as benzoin has a problem that the odor due to the intramolecular bond cleavage photopolymerization initiator is strong. Thus, studies have been made on intermolecular hydrogen abstraction type photopolymerization initiators with low odor as photopolymerization initiators.

  On the other hand, those using intermolecular hydrogen abstraction type photopolymerization initiators such as benzophenone generally have a slow curing speed, and therefore a tertiary amine compound as a sensitizer is generally used in combination to increase the curing speed. is there. However, in that case, after printing and coating a water-based printing ink composition and a water-based anchor varnish sequentially on a paper substrate, an active energy ray-curable overprint varnish composition is applied and cured with active energy rays. When applied, the tertiary amine penetrates into and dissolves the aqueous printing ink composition layer and aqueous anchor varnish layer that are printed and coated on the paper substrate, so that the adhesion of the overprint varnish layer Has been found to be greatly reduced.

Japanese Patent Laid-Open No. 11-080642

  Accordingly, the problem of the present invention is to provide an active energy ray-curable overprint varnish composition in which all the problems such as curability of the overprint varnish composition, adhesion to the lower layer, and odor are solved, and the It is to provide a paper product coated with an active energy ray-curable overprint varnish composition.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have at least one tertiary that acts as a photopolymerizable compound and a sensitizer as an active energy ray-curable overprint varnish composition. All the above problems can be solved by using a compound having an amino group and at least one acryloyl group, and using a compound containing an intermolecular hydrogen abstraction type photopolymerizable initiator as a photopolymerizable initiator. As a result, the present invention has been completed.

  That is, the present invention relates to (1) an active energy ray-curable overprint varnish composition containing a photopolymerizable compound and a photopolymerizable initiator, wherein the photopolymerizable compound is (A) at least one tertiary amino group. And at least one selected from compounds having at least one acryloyl group, and (B) a compound having a photopolymerizable unsaturated bond copolymerizable with the compound (A), (A) / (B) = Active energy ray curing, characterized in that it is contained at a mass ratio of 0.5 / 99.5 to 30/70, and the photopolymerizable initiator is an intermolecular hydrogen abstraction type photopolymerizable initiator. A mold overprint varnish composition is provided.

  Furthermore, the present invention provides an aqueous anchor varnish containing an aqueous emulsion in which an aqueous printing ink composition is printed partially or entirely on a paper substrate and a glass transition temperature is -20 ° C to 20 ° C. A paper product is provided in which the active energy ray-curable overprint varnish composition described in the above item (1) is applied, and the overprint varnish is cured with active energy rays.

  In the active energy ray-curable overprint varnish composition of the present invention, since the intermolecular hydrogen abstraction type photopolymerizable initiator is used as the photopolymerizable initiator, the problem of odor is solved.

  In the active energy ray-curable overprint varnish composition of the present invention, an intermolecular hydrogen abstraction type photopolymerization initiator is used as a photopolymerization initiator, but it acts as a photopolymerization compound and a sensitizer. Since a compound having a tertiary amino group and an acryloyl group is used, the curing speed is fast, and after curing, the compound having the tertiary amino group and the acryloyl group penetrates into the lower aqueous printing layer and aqueous anchor varnish layer. There is no problem of hindering adhesion.

  Thus, in the present invention, the active energy ray-curable overprint varnish composition having excellent curability and adhesion to the lower layer and having no odor problem, and the active energy ray-curable overprint varnish composition were applied. A paper product is obtained.

  Hereinafter, the present invention will be described in more detail.

<Constituent material of active energy ray-curable overprint varnish composition of the present invention>
The constituent materials of the active energy ray-curable overprint varnish composition of the present invention will be described.

(Photopolymerizable compound)
(A) Compound having at least one tertiary amino group and at least one acryloyl group which also has a function of a sensitizer. For example, N, N-dialkylacrylamide, N, N-dialkylaminoalkylacrylamide, N, N-dialkylamino Examples thereof include alkyl acrylate. The alkyl group in N, N-dialkylacrylamide may be the same or different, and examples thereof include a methyl group and an ethyl group. The alkyl groups in N, N-dialkylaminoalkyl acrylamide and N, N-dialkylaminoalkyl acrylate may be the same or different, and examples thereof include methyl, ethyl and the like, and alkylene groups include methylene group, ethylene group, ethylidene. Group, trimethylene group, propylene group, propylidene group and the like. Specific examples include N, N-dimethylacrylamide, N, N-dimethylamino-2-ethylacrylamide, N, N-dimethylamino-3-propylacrylamide, N, N-dimethylamino-2-ethylacrylate, N, N-dimethylamino-3-propyl acrylate etc. are mentioned. These compounds (A) can be used alone or in combination of two or more.

(B) Compound having photopolymerizable unsaturated bond copolymerizable with compound (A) The compound having a photopolymerizable unsaturated bond copolymerizable with compound (A) is a photopolymerizable unsaturated bond. And monomers and oligomers having

  Examples of the monomer having one photopolymerizable unsaturated bond in the molecule include alkyl (meth) acrylates such as methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; benzyl methacrylate Aralkyl (meth) acrylates such as benzyl acrylate; alkoxyalkyl (meth) acrylates such as butoxyethyl methacrylate and butoxyethyl acrylate; polyalkylene glycol monoalkyls such as diethylene glycol monoethyl ether, triethylene glycol monobutyl ether and dipropylene glycol monomethyl ether (Meth) acrylic acid ester of ether; hexaethylene glycol monofer Polyalkylene glycol (meth) acrylic acid esters of mono- aryl ethers such as ether, isobornyl (meth) acrylate; glycerol (meth) acrylate; and 2-hydroxyethyl (meth) acrylate can be exemplified.

  Examples of monomers having two or more photopolymerizable unsaturated bonds in the molecule include bisphenol A di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,3-butylene glycol di (meth). Acrylate, diethylene glycol di (meth) acrylate, glycerol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, Dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate can be exemplified.

  As the oligomer having a photopolymerizable unsaturated bond, one obtained by appropriately polymerizing one or more of the above monomers can be used.

  The said compound (B) can be used individually or in combination of 2 or more types.

(Ratio of the compound (A) / compound (B))
The ratio of said compound (A) / compound (B) is 0.5 / 99.5-30 / 70 by mass ratio, Preferably it is 1 / 99-15 / 85. If the ratio of the compound (A) is less than the above range, a sufficient curing rate cannot be obtained, while if it exceeds the above range, the curing rate tends to decrease.

(Intermolecular hydrogen abstraction type photopolymerization initiator)
Specific examples include benzophenone series (benzophenone, methyl-2-benzoylbenzoate, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone), thioxanthone series (2-methylthioxanthone, 2, 4-diethylthioxanthone, 2-chlorothioxanthone), quinone series (anthraquinone, naphthoquinone) and the like can be exemplified.

  The amount of the intermolecular hydrogen abstraction type photopolymerization initiator used can be used in an amount conventionally used in this type of curable composition, for example, 1 to 1 in the active energy ray curable overprint varnish composition. 20% by mass.

(Additives that can be added as needed)
Depending on the required performance, a resin such as a (meth) acrylic acid-modified resin, a leveling agent, a wax, an antiseptic, an antibacterial agent, a thermal polymerization inhibitor and the like can be added as necessary.

<Paper product of the present invention>
Next, a paper product to which the active energy ray-curable overprint varnish composition of the present invention is applied will be described.

  In the paper product of the present invention, for example, a water-based printing ink composition is printed on a paper base material (paper such as carton or glossy paper) partially or entirely, and a glass transition temperature of −20 ° C. to After applying an aqueous anchor varnish containing an aqueous resin emulsion at 20 ° C. and further applying an active energy ray-curable overprint varnish composition, the overprint varnish is cured with an active energy ray and molded. Can be obtained.

  As the water-based printing ink composition, a water-based flexographic ink composition conventionally used in flexographic printing can be used. For example, an aqueous flexographic ink composition mainly containing a binder resin such as a styrene / maleic acid copolymer resin, a styrene / acrylic copolymer resin, and an acrylic copolymer resin, a colorant, a basic compound, and an aqueous solvent. Things can be used.

  As the aqueous anchor varnish, an aqueous anchor varnish that can alleviate shrinkage that occurs when the active energy ray-curable overprint varnish is cured and can seal the active energy ray-curable overprint varnish can be used. Specifically, an aqueous anchor varnish containing an aqueous emulsion such as a styrene / butadiene rubber emulsion or an acrylic emulsion having a glass transition temperature of -20 to 20 ° C. can be exemplified.

  A water-based printing ink composition, a water-based anchor varnish, and an active energy ray-curable overprint varnish composition are sequentially printed and applied to a paper substrate such as a carton or glossy paper by a flexographic printing method, and then UV, electronic After curing with an active energy ray such as a wire, it can be further formed into a box shape or bag shape and used for paper products for packaging such as paper containers and paper bags.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “%” means “mass%”.

Examples 1-4
A water-based printing ink composition (Laptone HR manufactured by Sakata Inx Co., Ltd.) is printed on single glossy paper by the flexographic printing method. Aqueous anchor varnish (styrene / butadiene rubber emulsion with a glass transition temperature of 5 ° C is converted to solid content. The water-based anchor varnish containing 26% by mass) is applied by a flexographic printing method (using a Toya flexographic printing machine (made by Higashidani Steel Works Co., Ltd.) as a flexographic printing machine, the same shall apply hereinafter), and further on Table 1 The active energy ray-curable overprint varnish composition having the composition shown (the ratio of each component is expressed in mass%) is applied by a flexographic printing method, and then a conveyor type ultraviolet irradiation device (using a high-pressure mercury lamp) is used. The overprint varnish was cured by irradiating with ultraviolet rays to obtain a paper product.

Comparative Examples 1-5
A paper product was obtained in the same manner as in Examples 1 to 4 except that the active energy ray-curable overprint varnish composition having the composition shown in Table 2 was used (the ratio of each component is expressed by mass%). It was.

  In Examples 1-4 and Comparative Examples 1-5, the curability of the overprint varnish and the adhesion of the cured overprint varnish were evaluated as follows. The results are shown in Tables 1-2.

(Curable)
In the conveyor type ultraviolet irradiation device, the number of passes until the surface tack disappeared under the irradiation condition of 60 W / cm × 23 m was evaluated.

(Adhesion)
In the conveyor type ultraviolet irradiation device, after applying cello tape (manufactured by Nichiban Co., Ltd.) to the surface of the overprint varnish cured with the number of passes until the surface tack disappears under the irradiation condition of 60 W / cm × 23 m, it is peeled off, Evaluated by criteria.
○: Paper blur occurs.
X: Overprint varnish peels from lower layer (aqueous anchor varnish).

Claims (1)

A water-based printing ink composition is printed on a paper substrate partially or entirely, and an aqueous anchor varnish containing an aqueous emulsion having a glass transition temperature of −20 ° C. to 20 ° C. is coated thereon, and In the active energy ray-curable overprint varnish composition containing a photopolymerizable compound and a photopolymerizable initiator, the photopolymerizable compound is (A) N, N-dimethylamino-3-propylacrylamide or N, N -Dimethylamino-2-ethyl acrylate and (B) a compound having a photopolymerizable unsaturated bond copolymerizable with the compound (A): (A) / (B) = 0.5 / 99.5 The photopolymerization initiator is a benzophenone-based, thioxanthone-based, or quinone-based intermolecular hydrogen abstraction-type photopolymerizable initiator. A paper product obtained by applying an active energy ray-curable overprint varnish composition and curing the overprint varnish with active energy rays .