JP2013035976A - Active energy ray-curable overprint varnish - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active energy ray-curable two-layer type overprint varnish that is applied on paper or plastic film becoming a substrate or a printed material on which printing is performed, and in which there is not a ruled line crack when being cured while maintaining fundamental overprint performances such as the adhesion with a substrate and glossiness; and to provide a method of manufacturing a printed material on which an overprint layer is provided, and printed material on which an overprint layer is provided.SOLUTION: The active energy ray-curable two-layer type overprint varnish is a two-layer type overprint varnish that is applied on paper or plastic film becoming a substrate or a printed material in which printing is performed on them, wherein in an applying order, the durometer hardness of a cured product of a first layer overprint varnish (value measured based on Japan Industrial Standard JIS K7215) is smaller than that of a cured product of a second layer overprint varnish.

Description

  The present invention relates to an active energy ray-curable overprint varnish used for providing an overprint layer on a base paper, plastic film or printed matter printed thereon.

Magazine covers, picture books, posters, printed materials such as calendars, and paperware products such as cosmetic cases are printed with oil-based offset printing ink, etc., and then the printed surface is improved in scratch resistance and blocking resistance, and gloss is imparted. An overprint varnish is applied for the purpose.
The overprint varnish is applied to all or part of these printed materials, but may be applied directly to unprinted paper or plastic film. It may be applied to the entire printed surface, or may be applied partially to form a pattern.
As such overprint varnishes, various solvents such as solvent-based, water-based, and oxidative polymerization systems have been used. Recently, however, an oil-based offset that requires a long time for drying is required, especially for improving productivity. For printing inks, active energy ray-curable overprint varnishes that are cured and dried immediately after application have been developed and used.
In addition, since a paper container product is bonded and assembled after overprinting, it is required to have a gluing suitability (property that can be pasted with glue).

  Since the active energy ray-curable overprint varnish is instantly cured by ultraviolet irradiation, internal stress is likely to occur in the cured coating, and ruled line cracking is likely to occur in post-processing. Therefore, for example, Patent Document 1, Patent Document 2, Patent Document 3, and the like disclose examples in which the composition of the overprint varnish is devised in order to prevent ruled line cracking.

However, in these patent documents, ruled line breakage is not completely prevented even in the evaluation in the examples. In addition, Patent Documents 2 and 3 describe that the gloss is improved, but since the evaluation test has not been performed in the examples, it is unclear how much the gloss is actually.
In Patent Document 4, an underprint layer is provided partially or entirely on the surface of a print layer using an ultraviolet curable ink, and an overprint layer is provided on the print layer and the underprint layer. An ultraviolet curable varnish composition for an overprint layer, which is used for producing a printed material in which an overprint layer on the underprint layer forms a concavo-convex pattern by a repellency phenomenon, is disclosed. Here, although it is difficult to generate cracks as one of the issues, the provision of two layers, an undercoat layer and an overprint layer, is for forming an uneven pattern due to the repelling phenomenon, It is not intended to prevent cracks).

JP-A-5-263012 JP-A-8-120218 JP-A-8-120219 JP 2007-161998 A

  Accordingly, the present invention is an active energy ray-curable two-layer overprint varnish that is applied onto a base paper, plastic film, or printed matter printed thereon, and when cured, adheres to the base material. Active energy ray curable two-layer overprint varnish without cracks on the ruled line, while maintaining the basic performance of overprinting such as durability and gloss, and a method for producing printed matter with an overprint layer, and an overprint layer The purpose is to provide printed materials.

  As a result of intensive studies, the inventors of the present invention have two types of active energy rays: a varnish that gives a soft cured product and a varnish that gives a harder cured product on paper, a plastic film, or a printed material printed thereon. It discovered that the said subject could be solved by apply | coating and hardening a curable overprint varnish in this order, and completed this invention.

That is, the present invention
(1) A two-layer overprint varnish that is applied onto a base paper, a plastic film, or a printed matter printed thereon, and in the order of application, the durometer hardness of the cured product of the first layer overprint varnish ( This is an active energy ray-curable two-layer overprint varnish set having a value measured according to Japanese Industrial Standard JIS K7215) smaller than that of the cured second layer overprint varnish.
In (1), a soft layer is first formed on a base material, and then a harder layer is formed to prevent ruled line cracking, and a harder layer is formed thereon to provide gloss, The overprint varnish such as frictional properties that are basically required can be imparted.

The present invention also provides:
(2) The durometer hardness of the cured product of the first layer overprint varnish is HDA 10 to 75, and the durometer hardness of the cured product of the second layer overprint varnish is HDA 70 to 100. The active energy ray-curable two-layer overprint varnish.
(2) shows a preferable range of durometer hardness of the first layer (soft layer) and the second layer (hard layer).

The present invention also provides:
(3) The active energy ray-curable two-layer overprint varnish according to (1) or (2), wherein the first layer overprint varnish contains a monofunctional acrylic monomer,
(4) The active energy ray-curable two-layer overprint varnish according to any one of (1) to (3), wherein the second layer overprint varnish contains a bifunctional or higher acrylic monomer;
It is.
In (3) and (4), the kind of monomer preferably used for the varnish of the first layer (soft layer) and the second layer (hard layer) is defined. Monomers that form a crosslinked structure, such as difunctional or higher monomers, are mainly used in the second layer (hard layer).

The present invention also provides:
(5) On the base material, the first layer overprint varnish is applied, irradiated with an active energy ray and cured, and then the second layer overprint varnish is applied thereon and activated. A method for producing an overprinted product, characterized by curing by irradiating energy rays;
(6) A printed matter in which two overprint varnish layers are formed on the substrate, and the first layer overprint varnish is applied and cured by irradiation with active energy rays. It is an overprinted product obtained by applying the second layer overprint varnish thereon and irradiating with an active energy ray to cure.

  The active energy ray-curable two-layer overprint varnish of the present invention is applied to a base paper, plastic film or printed matter printed thereon, and when cured with active energy rays, adheres to the base material. Excellent resistance and gloss, almost no ruled line cracks, excellent resistance to rubbing and pasting (property that can be pasted with glue), little yellowing and odor, smooth coating surface and pinhole It has the feature that there is no.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that this embodiment is merely an embodiment for carrying out the present invention, and the present invention is not limited by this embodiment, and various modified embodiments can be made without departing from the gist of the present invention. Is possible.

  When the two-layer overprint varnish of the present invention is cured with active energy rays, the first layer is softer and the second layer is more in order of application on the base paper, plastic film or printed matter printed thereon. It is characterized by being a hard layer. Here, durometer hardness (value measured according to Japanese Industrial Standard JIS K7215) is used as an index of softness / hardness.

  In the two-layer overprint varnish of the present invention, the varnish used for the first layer contains an oligomer, a monofunctional (meth) acrylate monomer, a radical polymerization initiator, and an additive.

  Examples of the oligomer include polyester acrylate oligomers, epoxy acrylate oligomers, urethane acrylate oligomers, polyether acrylate oligomers, and urethane acrylate oligomers are particularly preferably used. Its content is 10 to 70% by weight, preferably 15 to 60%, based on the varnish of the first layer.

Examples of the monofunctional (meth) acrylate monomer include (meth) acrylic acid alkyl esters, phenoxyalkyl esters, alicyclic alkyl esters, alkoxyalkyl esters, and the like. The content is 10 to 80% by weight, preferably 20 to 75% by weight.
In order to adjust the hardness, adhesion, etc. of the cured product, a bifunctional monomer such as that used in the second layer, a trifunctional monomer such as trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, etc. Tetrafunctional monomers can also be used as appropriate.

Examples of radical polymerization initiators used for curing with active energy rays include photocleavable benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin series such as α-acrylobenzoin, Irgacure 9 07 (manufactured by BASF, 2-methyl- 1- (4-methylthiophenyl) -2-morpholinopropan-1-one), Irgacure 3 6 9 (manufactured by BASF Corporation 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone ), Irgacure 6 5 1 (Benzyl methyl ketal manufactured by BASF)
Irgacure 1 8 4 (BASF 1-hydroxycyclohexyl phenyl ketone)
Darocur 1 1 73 (Merck 2-hydroxy-2-methyl-1-phenylpropan-1-one), Darocur 1 1 1 6 (Merck 1- (4-isopropylphenyl) -2-hydroxy-2 -Methylpropan-1-one), 4-(
2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, Z
L I 3 3 3 1 (Ciba Specialty Chemicals 4- (2-acryloyl-oxyethoxy) phenyl-2-hydroxy-2-propyl ketone, diethoxyacetophenone, Esacure K I P 1
0 (made by Ramberty), Lucillin TPO (made by BASF), BTTB (Japanese fats and oils (
Co., Ltd.), CGI 1770 (manufactured by Ciba Specialty Chemicals, etc.).
Also, hydrogen abstraction type benzophenone, p-methylbenzophenone, p-chlorobenzophenone, tetrachlorobenzophenone, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl-diphenylsulfide, 2-isopropyl Aryl ketone initiators such as thioxanthone, 2,4-dimethylthioxanthone, 2,4 diethylthioxanthone, 2,4 dichlorothioxanthone, acetophenone, 4
, 4'-bis (diethylamino) benzophenone, 4, 4'-bis (
Dimethylamino) benzophenone, p-dimethylaminoisoamyl benzoate, p
Examples thereof include dialkylaminoaryl ketone initiators such as dimethylaminoacetophenone, thioxanthone, xanthone, amino alcohol MDA and halogen-substituted polycyclic carbonyl initiators.
These can be used alone or in combination. These initiators are 0... 0 in the varnish of the first or second layer. It is used in the range of 1 to 30% by weight, preferably 1
It is in the range of ~ 15% by weight.

  Examples of the additive used in the present invention include polymerization inhibitors, polymerization initiation assistants, antifriction agents, leveling agents, and antifoaming agents.

  As the polymerization initiation aid, tertiary amines that are hydrogen donors are used. Specifically, aliphatic amines such as triethanolamine, methyldiethanolamine, triisopropanolamine, 4,4′-diethylaminobenzophenone, ethyl 2-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoate Aromatic amines such as isoamyl acid can be mentioned, and triethanolamine, methyldiethanolamine, dibutylethanolamine, triisopropanolamine, and 4,4′-diethylaminobenzophenone are preferable.

  Antifriction agents include plant waxes such as carnauba and wax, animal waxes such as whale wax and lanolin, petroleum waxes such as montan (and natural waxes), and synthetic hydrocarbon waxes such as sazol and polyethylene. can do.

As the leveling agent and antifoaming agent, silicone additives such as silicone oil and silicone acrylate, acrylic additives such as acrylic polymer, and the like can be used.

  In the two-layer overprint varnish of the present invention, the varnish used for the second layer contains an oligomer, a bifunctional or higher (meth) acrylate monomer, a radical polymerization initiator and an additive.

Bifunctional (meth) acrylate monomers include tricyclodecane dimethylol di (meth) acrylate, tricyclodecane dimethylol dicaprolactonate di (
(Meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethylene oxide modified 1,6-hexanediol di (meth) acrylate, modified Examples include 1,6-hexanediol di (meth) acrylate.

Examples of the trifunctional (meth) acrylate monomer include trimethylolpropane tri (meth) acrylate and ethoxylated glycerin triacrylate.
Examples of the tetrafunctional (meth) acrylate monomer include ditrimethylolpropane tetraacrylate and pentaerythritol tetraacrylate.
The content of these bifunctional or higher (meth) acrylates is 10 to 80% by weight, preferably 20 to 75% by weight, based on the varnish of the second layer.

  As the oligomer, the radical polymerization initiator, and the additive, the same materials as those in the first layer are used as appropriate. In addition, a monofunctional monomer such as that used in the first layer can be used as appropriate in order to adjust the hardness, adhesion and the like of the cured product.

  The overprint varnish of the present invention is produced by mixing the above-described components for both the first layer and the second layer, and optionally by heating and mixing, and the viscosity is appropriately selected depending on the coating method.

  Moreover, the printed matter of the present invention prints the first layer overprint varnish using a gravure roll coater, an offset gravure roll coater, a flexo roll coater, etc. on paper, plastic film or printed matter printed thereon. Alternatively, it is prepared by coating and irradiating and curing active energy rays, and then printing or coating the second layer overprint varnish and irradiating and curing active energy rays.

  The overprint varnish of the present invention can be widely used for substrates such as paper, plastic film, oil-based offset printed matter, and UV offset printed matter.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Materials used]
The materials used in the present invention are summarized in Tables 1-6. In the following examples and comparative examples, material names are represented by abbreviations shown in Tables 1-6. That is, the materials in Table 1 are A1-A3, the materials in Table 2 are B1, B2, the materials in Table 3 are C1-C3, the materials in Table 4 are D1, D2, the materials in Table 5 are E1-E3, and in Table 6. The material is abbreviated as F1 to F3. Further, parts by weight are expressed in parts, and% by weight is expressed in%.

[Production of overprinted printed matter]
Each composition shown in Table 7 was stirred and mixed (heated if necessary) to prepare an overprint varnish.
The overprint varnish to be the first layer prepared above was applied with a bar coater # 3 to a printed matter obtained by printing oil-based offset ink on paper (Hokuetsu Maricoat (Hokuetsu Paper Coated Ball)). This coated product is placed on a conveyor of 12 m / min, and a high pressure mercury lamp ozone type (Fusion UV Systems Japan Co., Ltd., F300S UV lamp system) having an intensity of 140 mJ / cm ² at a distance of 5 cm above the conveyor. This was repeated twice, passing under.
Furthermore, the overprint varnish to be the second layer was applied with a bar coater # 4 and cured by the same method to produce an overprint printed matter.
In the case of coating with only one layer, it was coated with a bar coater # 4 and cured by the same method.

[Evaluation method]
(1) Durometer hardness 0.015 g of Irg819 (manufactured by BASF) was added as a photopolymerization initiator to 3 g of the composition obtained by removing the photopolymerization initiator and other additives from each of the overprint varnish compositions shown in Table 7. The mixture was poured into a glass container formed by placing a glass ring with an inner diameter of 2.5 cm and a height of 1 cm on a glass plate, and the container was placed on a conveyor of 12 m / min, at a distance of 5 cm above the conveyor. The high-pressure mercury lamp ozone type (Fusion UV Systems Japan Co., Ltd., F300S UV lamp system) having an intensity of 140 mJ / cm ² was passed under one lamp, and this was repeated 6 times.
Two of the same cured products obtained as described above were stacked to a thickness of 6 mm or more, and the durometer hardness was measured according to Japanese Industrial Standard JIS K7215.
In setting the curing conditions, measure the durometer hardness by changing the type and amount of the polymerization initiator, the intensity of ultraviolet rays and the number of irradiations, and based on the results, completely cured under the above conditions The above method was adopted.

  For the overprinted material obtained in [Preparation of overprinted material], (2) Ruled line breakage, (3) Adhesion, (4) Gloss, (5) Friction resistance, (6) Suitability for pasting by the following method , (7) Odor, (8) Yellowing, (9) Leveling.

(2) Cracking of the ruled line Place the ruled line plate on the evaluation object (paper), apply a certain force from above, make the paper uneven, perform valley fold and mountain fold once, and observe the cross section.
○: Even if the valley fold and the mountain fold are performed once, no crack is generated or very little.
Δ: When valley fold and mountain fold are performed once, a crack is generated, and part of the varnish peels when touched.
X: When the valley fold and the mountain fold are performed once, a crack is generated. When touched, most of the varnish is peeled off, or the crack is generated only by the valley fold.

(3) Adhesion After leaving the overprinted material for one day, the cellophane adhesive tape (CT405AP-18 manufactured by Nichiban Co., Ltd.) was pressed against the printing surface, and when the cellophane adhesive tape was peeled off, there was almost no ink on the tape side. The case where it was not taken or a part was taken was evaluated as ◯, the case where more than half was taken as Δ, and the case where it was almost taken as x.

(4) Gloss After overprinting was left for 1 day, it was measured 5 times using a handy photometer (HG-268, manufactured by Suga Test Instruments Co., Ltd.). The average value was calculated and evaluated as follows.
○: 85 or more Δ: 80 to less than 85 ×: less than 80

(5) Friction resistance test After leaving the overprinted material to stand for 1 day, it was applied to JIS-P8136 using a Gakushin type fastness tester (dye fastness friction tester FR-2, manufactured by Suga Test Instruments Co., Ltd.). Similarly, the quality paper was used as a friction paper, and the change in the friction surface after 300 reciprocations at a load of 500 g was visually evaluated in three stages as follows.
○: No change or slight scratches are observed.
Δ: Peeling is observed in part (less than 50%).
X: Peeling is observed in many parts (50% or more).

(6) Adhesive suitability After leaving the overprinted print for one day, apply an emulsion adhesive (manufactured by Niei Kogyo Co., Ltd .; AV-650N) with a bar coater # 8 and fold it so that the adhesive coated surfaces adhere to each other. I put it on the board and put a 1kg weight on it and left it for a day. When this adhesive surface was to be peeled off, those that peeled off were marked with ◯, and those that did not peel off were marked with ×.

(7) Odor About the overprinted prints, three panelists sniffed the odor, evaluated 1 as the strong odor, 2 as the weak odor, 3 as the one that hardly felt the odor, and evaluated the average value. The points were evaluated according to the following criteria.
○: Evaluation point is 2.3 or more Δ: Evaluation point is less than 2.3 2.0 or more ×: Evaluation point is less than 2.0

(8) Yellowing degree Overprinted printed matter was measured with a color difference meter (X-Rite Corporation, X-Rite 938 Spectrodensitometer), and evaluated by the degree of yellowing ΔE compared to that of the unprinted portion of the base material before overprinting. did.
○: 0 <ΔE ≦ 3
Δ: 3 <ΔE ≦ 5
×: 5 <ΔE

(9) Leveling
The surface of the overprinted material (Method 1) produced by the above [Preparation of Overprinted Product] and the overprinted material (Method 2) produced by the gravure proofing machine was visually observed and evaluated according to the following criteria.
○: No repellency was found in Method 1 and no repellency was found in Method 2;
Δ: A small amount of repellency was found in Method 1.
×: Method 1 with repellency.

[Examples and Comparative Examples]
Each overprint varnish composition of Table 7 was used in the combination of Tables 8 and 9, and overprinted prints were prepared according to [Preparation of Overprinted Print]. The evaluations (2) to (8) were performed on each of these overprinted prints, and the results are shown in Table 8.

From Table 8, the overprint printed matter in which a durometer-hard soft layer and a hard layer are formed as an overprint layer in this order on the oil-based offset printed matter is excellent in adhesion and gloss, and almost no cracks are observed on the ruled line. In addition, it is excellent in friction resistance and suitability for pasting, has little yellowing when cured, has little odor, and has a smooth coating surface.
On the other hand, according to Table 9, the conventional products (Comparative Examples 1 and 2), which is an overprint varnish with only one layer, have problems in ruled line cracking and adhesiveness. Moreover, in the overprint varnish of a combination of those having a high durometer hardness (Comparative Examples 10 to 11), only a soft one (Comparative Example 3), and only a hard one (Comparative Example 4), the basic performance as an overprint is improved. You can only get what you lack.

Claims (6)

  It is a two-layer overprint varnish that is applied onto paper, plastic film or printed material printed on them, and in the order of application, the durometer hardness of the cured product of the first layer overprint varnish (Japanese Industrial Standard) An active energy ray-curable two-layer overprint varnish characterized in that the value measured according to JIS K7215 is smaller than that of the cured product of the second layer overprint varnish.   The durometer hardness of the cured product of the first layer overprint varnish is HDA 10 to 75, and the durometer hardness of the cured product of the second layer overprint varnish is HDA 70 to 100. Line-curable two-layer overprint varnish.   The active energy ray-curable two-layer overprint varnish according to claim 1 or 2, wherein the first layer overprint varnish contains a monofunctional acrylic monomer.   The active energy ray-curable two-layer overprint varnish according to any one of claims 1 to 3, wherein the second layer overprint varnish contains a bifunctional or higher acrylic monomer.   On the base material, the first layer overprint varnish is applied and irradiated with an active energy ray and cured, and then the second layer overprint varnish is applied thereon and an active energy ray is applied. A method for producing an overprinted product, which comprises curing by irradiation.   A printed matter in which two overprint varnish layers are formed on the substrate, and the first layer overprint varnish is applied and cured by irradiating with active energy rays. An overprint printed material, wherein the second layer overprint varnish is applied and irradiated with an active energy ray to be cured.