Printed matter and method of manufacturing the same

Abstract

A printed matter, provided with: a printed object having a surface on which printing is to be performed, an oily ink layer provided on the surface, and a water-based varnish layer provided in a manner so as to cover the oily ink layer, the water-based varnish layer containing a dried product of an emulsion-type water-based varnish composed of different resins and formed in a manner so as to be thicker than the oily ink layer.

Description

Technical Field

[0001] This disclosure relates to printed matter and methods of manufacturing thereof. Background Technology

[0002] In the past, various printing methods have been developed, such as UV offset printing and oil-based offset printing. UV offset printing uses UV-curable inks containing photopolymerization initiators and monomers. Oil-based offset printing uses oil-based inks, and sometimes, during printing, a special powder is sprayed onto the undried oil-based ink.

[0003] Each printing method has its advantages and disadvantages. The printing method should be selected according to the purpose and quality requirements of the printed material. UV offset printing has the advantages of quick drying and immediate processing after printing. On the other hand, it has the following disadvantages: (1) It consumes a lot of electricity due to UV irradiation; (2) Due to quick drying, it is easy to leave unevenness on the surface of the ink layer; (3) Compared with oil-based offset printing, the color gamut is narrower; (4) Starting from overseas, there are concerns about the effects of photopolymerization initiators on the human body, and countries are avoiding its use in food packaging.

[0004] Compared with UV offset printing, oil-based offset printing has the advantage of a wide color gamut, but it also has the following disadvantages: (1) The ink will not dry if it is not left to stand for about a day after printing; (2) Oil-based inks solidify due to oxidation and polymerization as they move slowly. Therefore, even if a varnish layer is formed by covering the ink layer to impart gloss, the surface smoothness of the varnish layer will be lost due to a phenomenon called dry down, thus reducing the gloss. Patent Document 1 discloses a method for manufacturing carton base paper by applying heat and pressure to the varnish layer using an embossing machine and performing a gloss finishing process (hot pressing).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-117027 Summary of the Invention

[0008] The problem to be solved by the present invention

[0009] In order to obtain glossy printed matter through oil-based offset printing, as described in Patent Document 1, it is believed that a post-processing hot-pressing process is required for the oil-based ink layer and the varnish layer. That is, it is believed that without hot-pressing, it is difficult to control the smoothness of the surface of the varnish layer covering the oil-based ink layer.

[0010] This disclosure provides a printed matter having excellent gloss even without hot pressing the varnish layer during its manufacturing process, comprising an oil-based ink layer and a varnish layer disposed in such a manner as to cover the oil-based ink layer, and a method thereof.

[0011] Methods for solving problems

[0012] In order to effectively produce high-gloss printed materials using oil-based inks, the inventors conducted repeated and in-depth research, resulting in the following invention. Specifically, the printed material disclosed herein comprises: a printable material having a surface to be printed on, an oil-based ink layer disposed on the surface, and a water-based varnish layer disposed to cover the oil-based ink layer. The water-based varnish layer comprises dried emulsion-type water-based varnish composed of different resin combinations and is formed to be thicker than the oil-based ink layer.

[0013] By making the water-based varnish layer thicker than the oil-based ink layer, the impact of surface unevenness of the oil-based ink layer on the surface smoothness of the water-based varnish layer can be effectively suppressed. Therefore, even without hot pressing, the surface of the water-based varnish layer can be made sufficiently smooth, resulting in excellent gloss. The water-based varnish layer is formed by drying an emulsion-type water-based varnish containing different resin combinations, with the option to select a hard resin as at least a portion of the resin. This also helps improve the surface smoothness of the water-based varnish layer, thereby contributing to improved gloss. After forming the emulsion-type water-based varnish film, the water-based varnish layer is formed by evaporating the water contained in the film.

[0014] One aspect of this disclosure relates to a method for manufacturing printed matter. The method includes: a step of forming a coating film of an emulsion-type water-based varnish composed of different resin combinations on the surface of an oil-based ink layer; and a step of forming a water-based varnish layer containing a dried product of the water-based varnish on the surface of the oil-based ink layer by drying the coating film, wherein the coating film is formed such that the water-based varnish layer is thicker than the oil-based ink layer.

[0015] The effects of the invention

[0016] According to this disclosure, a printed matter having excellent gloss is provided even without hot pressing the varnish layer during its manufacturing process, in which an oil-based ink layer and a varnish layer provided in a manner covering the oil-based ink layer are provided, and a method thereof. Attached Figure Description

[0017] [ Figure 1 ] Figure 1 A cross-sectional view is shown schematically for illustrating one embodiment of the printed matter involved in this disclosure.

[0018] [ Figure 2 ] Figure 2A cross-sectional view is shown to schematically illustrate other embodiments of the printed matter involved in this disclosure. Detailed Implementation

[0019] The embodiments of this disclosure will now be described in detail. It should be noted that the present invention is not limited to the embodiments described below.

[0020] Figure 1 A cross-sectional view of the printed material according to this embodiment is shown schematically. The printed material 10 shown in the figure includes: a printable 1 having a surface 1a to be printed on, an oil-based ink layer 3 disposed on the surface 1a, and a water-based varnish layer 5 disposed to cover the oil-based ink layer 3. The water-based varnish layer 5 is a layer formed using an emulsion-type water-based varnish and is formed to a thickness greater than that of the oil-based ink layer 3.

[0021] The printed material 1 is, for example, paper. Specific examples of paper include high-grade paper, special high-grade paper, coated paper, art paper, cast-coated paper, imitation paper, and kraft paper. The mass of the paper per unit area is, for example, only 20–500 g / m². 2 Or 25~400g / m 2 Within a certain range. The printed material 1 can, for example, be made of a composite material containing paper and resin.

[0022] Oil-based ink layer 3 is a layer formed using oil-based ink and through offset printing. The thickness of oil-based ink layer 3 ( Figure 1 The thickness T3 of the oil-based ink layer 3 is preferably 1.5 μm or less, more preferably 1.3 μm or less, and even more preferably 1.1 μm or less. By making the thickness of the oil-based ink layer 3 1.5 μm or less, the influence of the surface unevenness of the oil-based ink layer 3 on the surface smoothness of the water-based varnish layer 5 can be sufficiently suppressed. Therefore, even without hot pressing, the surface of the water-based varnish layer 5 can be made sufficiently smooth. The lower limit of the thickness of the oil-based ink layer 3 is, for example, 0.5 μm. By using concentrated (high-concentration) oil-based ink, a clear oil-based ink layer 3 can be formed even if the thickness of the oil-based ink layer 3 is in the range of 0.5 to 1.5 μm. In concentrated oil-based ink, the solvent content is low. Therefore, by using concentrated oil-based ink, the drying time can also be shortened. It should be noted that concentrated oil-based ink refers to ink in which the mass of solvent is 60% or less by mass relative to the total mass of the oil-based ink. The solvent can be 30% by mass or more, preferably 40-50% by mass.

[0023] The thickness of the oil-based ink layer 3 can be determined using an optical microscope via interference spectrometry, which utilizes the phenomenon of light interference. Alternatively, the thickness of the oil-based ink layer 3 can be determined by observing a cross-section of the printed material 10 or an intermediate product (e.g., the substance before the formation of the water-based varnish layer 5) using an optical microscope. Vegetable oil inks can be used as examples of oil-based inks. Biomass inks can also be used instead of vegetable oil inks. Biomass inks are cured products containing colorants, polyols, and isocyanate compounds, wherein at least one of the polyols and isocyanate compounds contains components derived from biomass.

[0024] Waterborne varnish layer 5 is a layer formed using an emulsion-type waterborne varnish and through offset printing. Waterborne varnish layer 5 contains a dried product of a waterborne varnish emulsion comprising different resin combinations. Examples of resins contained in waterborne varnish layer 5 include acrylic resins, urethane resins, and silicone resins. The combined resins may be chemically bonded to each other, or they may be included as individual resins in the waterborne varnish. There are no limitations on the combination of resins; for example, it may be a combination of at least two selected from acrylic resins, urethane resins, and silicone resins.

[0025] As described above, the water-based varnish layer 5 is formed in a manner that is thicker than the oil-based ink layer 3. The thickness of the water-based varnish layer 5 ( Figure 1 The thickness T5 of the water-based varnish layer 5 is preferably 2.5 μm or more, more preferably 2.7 μm or more, and even more preferably 2.9 μm or more. By making the thickness of the water-based varnish layer 5 2.5 μm or more, the influence of the surface unevenness of the oil-based ink layer 3 on the surface smoothness of the water-based varnish layer 5 can be sufficiently suppressed. Therefore, even without hot pressing, the surface of the water-based varnish layer 5 can be made sufficiently smooth. The upper limit of the thickness of the water-based varnish layer 5 is, for example, 5.0 μm. By making the thickness of the water-based varnish layer 5 5 5 less than 5.0 μm, it is preferable to have both fast drying in the process of forming the water-based varnish layer 5 and smoothness of the surface 5a of the water-based varnish layer 5 at a high level. The thickness of the water-based varnish layer 5 can also be determined using an optical microscope by interference spectrometry, which utilizes the interference phenomenon of light. The thickness of the water-based varnish layer 5 can also be determined by observing the cross-section of the printed matter 10 using an optical microscope.

[0026] The ratio (T5 / T3) of the thickness T5 of the water-based varnish layer 5 to the thickness T3 of the oil-based ink layer 3 is preferably 3 / 2 to 7 / 2, 8 / 5 to 3 / 1, 5 / 3 to 3 / 1, or 5 / 3 to 5 / 2, or it can also be 5 / 3 to 2 / 1, 2 / 1 to 5 / 2, or 8 / 5 to 5 / 2. By keeping the value of T5 / T3 within this range, the impact of the surface unevenness of the oil-based ink layer 3 on the surface smoothness of the water-based varnish layer 5 can be sufficiently suppressed.

[0027] The surface 5a of the water-based varnish layer 5 is sufficiently smooth and has excellent gloss. The gloss level of the surface 5a is preferably 60 or higher, more preferably 65 or higher, and even more preferably 70 or higher. An upper limit for the gloss level is, for example, 85. The gloss level referred to here is the value measured at an incident angle of 60 degrees according to the method described in JIS Z 8741-1997. In addition to the smoothness of the surface 5a, the gloss level of the surface 5a can also be adjusted to some extent by adjusting the composition of the water-based varnish layer 5 (e.g., increasing the solid content ratio).

[0028] The water-based varnish layer 5 preferably exhibits excellent abrasion resistance. To improve the abrasion resistance of the water-based varnish layer 5, wax can be used as an additive. From the viewpoint of operability of the printed matter 10, the surface 5a of the water-based varnish layer 5 preferably has a low coefficient of friction. To reduce the coefficient of friction of the surface 5a, silicone resin or wax can be used as an additive. The static coefficient of friction of the surface 5a is preferably 0.1 to 0.3, but can also be 0.2 to 0.3 or 0.1 to 0.2. The dynamic coefficient of friction of the surface 5a is preferably 0.05 to 0.15, but can also be 0.1 to 0.15 or 0.05 to 0.10.

[0029] <Methods for Manufacturing Printed Materials>

[0030] The manufacturing method of printed matter 10 includes the following steps.

[0031] (A) A process of forming a film of emulsion-type waterborne varnish composed of different resin combinations (not shown) on the surface of oil-based ink layer 3.

[0032] (B) A process of forming a water-based varnish layer 5 containing the dried product of water-based varnish on the surface of the oil-based ink layer 3 by drying the above-mentioned coating.

[0033] The water-based varnish layer is formed by drying the aforementioned coating. By forming the water-based varnish layer 5 to be thicker than the oil-based ink layer 3, a printed material 10 with excellent gloss can be obtained even if the water-based varnish layer 5 is not subjected to hot pressing during the manufacturing process of the printed material 10.

[0034] The embodiments of this disclosure have been described in detail above, but the present invention is not limited to the above embodiments. For example, in the above embodiments, an oil-based ink layer 3 is formed in such a way that it covers the entire surface 1a of the printed object 1, but the oil-based ink layer 3 may also be formed partially on the surface 1a. Figure 2 The printed material 20 shown includes: a printed material 1, an oil-based ink layer 13 partially formed on a surface 1a and consisting of multiple layers 13a, and a water-based varnish layer 15 disposed to cover the oil-based ink layer 13 and the surface 1a. In this configuration, the thickness of the water-based varnish layer 15 ( Figure 2Thickness T in 15 ) with a thickness greater than that of oil-based ink layer 13 ( Figure 2 Thickness T in 13 It is formed in a thick manner. It should be noted that, as... Figure 2 As shown, the thickness (T) of the water-based varnish layer 15 mentioned here... 15 The distance () refers to the distance from the surface 13b of the oil-based ink layer 13 to the surface 15a of the water-based varnish layer 15. The oil-based ink layer and the water-based varnish layer are preferably formed by a roll. It should be noted that these layers can also be formed by a chamber method instead of a roll method.

[0035] In the above embodiment, a method for manufacturing the printed material 10 without hot pressing was described. However, during the manufacturing process of the printed material, hot pressing (a process of applying pressure while heating the surface of the water-based varnish layer) can also be performed on the water-based varnish layer. By performing hot pressing, the surface of the water-based varnish layer can be made more highly smooth, and the reflective haze can be reduced while maintaining almost the same gloss as before hot pressing. That is, it achieves the effect of improving mirror finish while maintaining excellent gloss.

[0036] Example

[0037] The present disclosure will be described in more detail below through embodiments, but the present invention is not limited to the following embodiments.

[0038] The following materials were prepared in order to manufacture the printing section involved in the embodiments and comparative examples.

[0039] (1) Printed material

[0040] • Coated cardboard (manufactured by Rengo Co., Ltd., 310g / m²) 2 )

[0041] (2) Ink

[0042] • Oil-based inks: TOYO KING (registered trademark) NEX series (manufactured by Toyo Ink Co., Ltd.)

[0043] • UV-curable ink: FD Carton X (manufactured by Toyo Ink Co., Ltd.)

[0044] (3) Varnish

[0045] • Water-based varnish: Emulsion-type water-based varnish (manufactured by Toyo Ink Co., Ltd.)

[0046] • UV high-gloss varnish: FD Rioclear EX (manufactured by Toyo Ink Co., Ltd.)

[0047] It should be noted that the above-mentioned emulsion-type water-based varnish contains acrylic resin and silicone resin as solid components.

[0048] <Examples 1-4>

[0049] An ink layer and a varnish layer are sequentially formed on the surface of the coated paperboard using a roller. The materials used and the thickness of the layers are shown in Table 1.

[0050] <Comparative Examples 1-6>

[0051] An ink layer and a varnish layer are sequentially formed on the surface of a coated paperboard using either a roller or chamber method. The materials used and the thicknesses of the layers are shown in Table 2. It should be noted that in Comparative Examples 4-6, after forming the ink layer, the ink layer was irradiated with UV light to cure it. In Comparative Example 4, after forming the varnish layer, the varnish layer was irradiated with UV light to cure the ink layer. In Comparative Example 6, after forming the varnish layer, the varnish layer was hot-pressed under the following conditions.

[0052] Temperature: 125℃

[0053] Pressure: 25MPa

[0054] • Time: 0.2 seconds

[0055] <Evaluation>

[0056] The following evaluation is made of the printed materials involved in the embodiments and comparative examples.

[0057] (1) Measurement of gloss

[0058] The gloss was measured using a gloss meter (trade name: handheld gloss meter) manufactured by Horiba Corporation, at an incident angle of 60 degrees. The measurement was repeated 10 times, and the upper and lower limits are recorded in Tables 1 and 2.

[0059] (2) Evaluation of abrasion resistance

[0060] The abrasion resistance of the varnish layer was evaluated according to the method described in JIS K 5701-1. The varnish layer was visually observed at various points in time (10, 50, 100, 300, and 500 rubs), and the abrasion resistance was evaluated according to the following criteria. Tables 1 and 2 show the results.

[0061] 〇: No wear on the clear coat layer was detected.

[0062] △: Although wear on the varnish layer was confirmed, the ink layer was not exposed.

[0063] ×: The varnish layer is worn and the ink layer is exposed.

[0064] (3) Coefficient of friction

[0065] The static and dynamic friction coefficients of the varnish layer surface were determined using a vibration-type friction testing machine (manufactured by Tester Sangyo Co., Ltd.). Tables 1 and 2 show the results.

[0066] [Table 1]

[0067]

[0068] [Table 2]

[0069]

[0070] Explanation of symbols

[0071] 1…printed material, 1a…surface, 3, 13…oil-based ink layer, 13a…layer, 13b…surface, 5, 15…water-based varnish layer, 5a, 15a…surface, 10, 20…printed material

Claims

1. A printed matter, comprising: The printed object having the surface to be printed on An oily ink layer disposed on the surface, and A water-based varnish layer is provided in a manner that covers the oil-based ink layer. The water-based varnish layer comprises dried emulsion-type water-based varnishes composed of different resin combinations and is formed in a manner thicker than the oil-based ink layer. The ratio (T5 / T3) of the thickness T5 of the water-based varnish layer to the thickness T3 of the oil-based ink layer is more than 3 / 2 and less than 7 / 2. The thickness of the water-based varnish layer is 2.5 μm or more. The thickness of the oil-based ink layer is less than 1.5 μm.

2. The printed matter according to claim 1, wherein, The oil-based ink layer is formed from concentrated oil-based ink. Concentrated oil-based inks refer to inks in which the mass of the solvent is less than 60% of the total mass of the oil-based ink.

3. A method for manufacturing printed matter, comprising: The process of forming a water-based emulsion varnish film composed of different resin combinations on the surface of an oil-based ink layer; and The process of forming a water-based varnish layer containing the dried product of the water-based varnish on the surface of the oil-based ink layer by drying the coating film. The coating film is formed in such a way that the water-based varnish layer is thicker than the oil-based ink layer. The ratio (T5 / T3) of the thickness T5 of the water-based varnish layer to the thickness T3 of the oil-based ink layer is more than 3 / 2 and less than 7 / 2. The thickness of the water-based varnish layer is 2.5 μm or more. The thickness of the oil-based ink layer is less than 1.5 μm.

4. The method for manufacturing printed matter according to claim 3 further includes a step of applying pressure while heating the surface of the water-based varnish layer.

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