Paper printed matter and method for producing the same

Abstract

To realize color development as if being printed on plastic by paper printing.SOLUTION: A packaging material 1 constituting a packaging bag includes: a paper base material 2; an anchor coat varnish layer 4 laminated on a front surface of the paper base material 2; an ink layer 5 laminated on a front surface of the anchor coat varnish layer 4; an overprint varnish layer 6 laminated on a front surface of the ink layer 5; and a heat seal layer 3 laminated on a rear surface of the paper base material 2. A pattern (such as a commodity image and a commodity name) is formed on the packaging material 1 by the ink layer 5. The anchor coat varnish layer 4 is prepared by mixing a vinyl acetate chloride resin, an acrylic resin, and a siliceous extender pigment, so that the vinyl acetate chloride resin prevents ink from permeating the paper base material, the acrylic resin improves heat resistance, and the siliceous extender pigment improves color development of ink.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a paper print and a method for producing the same. [Background technology]

[0002] In response to environmental issues such as marine plastic pollution and global warming, there are an increasing number of cases where paper is used for product packaging in order to reduce the amount of plastic used.

[0003] Many product packages are printed with product images, product names, etc. Unlike plastic, paper has a rough surface and ink easily penetrates it, so ink is less likely to transfer to paper than plastic and a whitish appearance may result. To prevent this, paper with a resin on the surface has been proposed. Patent Document 1 describes a fiber structure with a resin-made filling layer formed on the surface. The gaps between the fibers are filled by the filling layer, and dot dropouts are significantly reduced, especially in solid areas. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-115956 A

[0005] By sealing the surface of the paper (fiber) with resin, the number of missing dots is reduced even when printing on paper, improving print quality. However, even if the number of missing dots is reduced, printing on paper still tends to have a whitish appearance compared to printing on plastic. Summary of the Invention [Problem to be solved by the invention]

[0006] The purpose of this invention is to achieve color reproduction (print quality) on paper that is as if it were printed on plastic.

[0007] The paper print according to the present invention is characterized by comprising a paper base material, an anchor coat varnish layer containing a resin and an extender pigment laminated on the surface of the paper base material, and an ink layer laminated on the surface of the anchor coat varnish layer. Since the ink layer expresses a pattern (product image, product name, etc.) on the paper print, the ink layer may be called a pattern layer.

[0008] The present invention also provides a method for producing a paper print. The method for producing a paper print according to the present invention is characterized in that an anchor coat varnish layer containing a resin and an extender pigment is laminated on the surface of a paper base material, and an ink layer is laminated on the surface of the anchor coat varnish layer.

[0009] According to this invention, the ink layer is laminated (printed) on the anchor coat varnish layer, not on the paper substrate. The anchor coat varnish layer contains a resin and an extender pigment. The resin prevents the ink from penetrating into the paper substrate. The extender pigment improves the color development of the ink layer. The anchor coat varnish layer also smoothes the surface of the paper substrate, which also contributes to improved print quality.

[0010] In one embodiment, the anchor coat varnish layer has a composition that contains 50 to 91 wt% of vinyl chloride acetate resin, 25 wt% or less of acrylic resin, and 3.0 to 25 wt% of silica-based extender pigment, the total of which is 100 wt%. If heat resistance is not required for the paper print, acrylic resin is not necessarily required, but generally, at least a few wt% of acrylic resin is contained in the anchor coat varnish layer. It goes without saying that inevitable impurities, that is, impurities that are present in the raw materials of the anchor coat varnish layer or that are inevitably mixed in during the manufacturing process and are essentially unnecessary but are allowed because they are in small amounts and do not affect the properties of the anchor coat varnish layer, may be contained in the anchor coat varnish layer.

[0011] According to this invention, by laminating an anchor coat varnish layer on a paper base material and then laminating an ink layer on the anchor coat varnish layer, it is possible to significantly increase the print density compared to laminating an ink layer on a paper base material. Prints with high print density have better color development than prints with low print density, and the whitishness peculiar to paper printing is not noticeable. It is possible to obtain a texture as if it were printed on plastic.

[0012] Preferably, an adhesive layer is laminated on the back surface of the paper base material. For example, the back surfaces of the side ends of the paper base material can be bonded together to make the paper base material into a cylindrical shape, or the back surfaces of the upper and lower ends of the cylindrical paper base material can be further bonded together to form a bag. For the adhesive layer, for example, a heat sealant that develops adhesiveness by applying heat and pressure can be used.

[0013] In one embodiment, an overprint varnish layer is laminated on the surface of the ink layer. The overprint varnish layer protects the ink layer, so that rubbing of the ink layer (pattern) can be prevented or suppressed.

[0014] Preferably, the layer thickness of the anchor coat varnish layer is 1 g / m 2 As a result, it is possible to reliably prevent the ink layer from penetrating into the paper base material and improve color development. [Brief description of the drawings]

[0015] [Figure 1] FIG. [Diagram 2] 2 is an enlarged end view of the packaging material taken along line II-II in FIG. 1. [Diagram 3] This is a close-up photograph of a packaging material with a layer of anchor coat varnish printed with black ink. [Figure 4] This is a close-up of a packaging material printed with black ink and without an anchor coat varnish layer. EXAMPLES

[0016] Fig. 1 shows the back surface of the packaging bag 10. Fig. 2 is an enlarged end view of the packaging material 1 constituting the packaging bag 10, taken along the line II-II in Fig. 1.

[0017] The packaging bag 10 is made by heat-sealing both side edges of the packaging material 1 to form a cylindrical body, and then heat-sealing the top and bottom ends of this cylindrical body. The portion formed by heat-sealing both side edges of the packaging material 1 is called the back seal portion 12. The top and bottom ends of the cylindrical body are indicated by the symbols 13 and 14. The back seal portion 12 is formed on the back of the packaging bag 10, approximately in the center in the width direction.

[0018] In the manufacturing process of the packaging bag 10 and the process of sealing the contents, after both side edges of the packaging material 1 are heat-sealed to form a cylindrical body, the bottom end 14 of the cylindrical body is heat-sealed to close the bottom opening, the contents are placed into the cylindrical body from the top opening, and then the top end 13 of the cylindrical body is heat-sealed to close the top opening, thereby completing the packaging bag 10 with the contents sealed in. For example, individually wrapped confectioneries are sealed in the packaging bag 10.

[0019] Referring to Figure 2, the packaging material 1 constituting the packaging bag 10 comprises a paper base material 2, a heat seal layer 3 laminated on the back surface (inner surface) of the paper base material 2, an anchor coat varnish layer (hereinafter referred to as AC varnish layer) 4 laminated on the front surface (outer surface) of the paper base material 2, an ink layer (pattern layer) 5 laminated on the surface of the AC varnish layer 4, and an overprint varnish layer (hereinafter referred to as OP varnish layer) 6 laminated on the surface of the ink layer 5.

[0020] The paper base material 2 may be one-sided glossy kraft paper, coated paper, double-glazed bleached kraft paper, pure white paper, art paper, or high-quality paper. In order to ensure appropriate strength and processing suitability, the thickness is preferably 30 to 100 g / m 2 A paper having a basis weight of 1000 g is used.

[0021] For the heat seal layer 3, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, unstretched polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, etc. may be used. A heat seal agent may also be applied, and ionomer-based, polyethylene-based, EVA-based, elastomer-based, chlorinated PP-based, acrylic-based, polyester-based, EVA-based (water-based) heat seal agents may be used. By laminating the heat seal layer 3 on the back surface (inner surface) of the paper base material 2, it is possible to form the back seal portion 12 by heat sealing as described above, or to close the upper and lower ends 13, 14. If it is not necessary to form the packaging material 1 into a packaging bag 10, the heat seal layer 3 does not necessarily have to be laminated.

[0022] The AC varnish layer 4 is prepared by mixing chlorovinyl acetate resin, acrylic resin, and silica-based extender pigment. The chlorovinyl acetate resin prevents the ink from penetrating into the paper base material, the acrylic resin improves heat resistance, and the silica-based extender pigment improves the color development of the ink. In addition, applying the AC varnish layer 4 to the paper base material 2 also smoothes the surface of the paper base material (the surface on which the ink layer 5 is laminated).

[0023] The AC varnish layer 4 has a composition containing 50-91 wt% vinyl chloride acetate resin, 25 wt% or less acrylic resin, and 3.0-25 wt% silica-based extender pigment, the total of which is 100 wt%. If heat resistance is not required for the packaging material 1, acrylic resin is not necessarily required, but generally, at least a few wt% of acrylic resin is contained in the AC varnish layer 4. It goes without saying that the AC varnish layer 4 may contain unavoidable impurities, that is, impurities that are present in the raw materials of the AC varnish layer 4 or that are unavoidably mixed in during the manufacturing process and that are essentially unnecessary but are permitted because they are in small amounts and do not affect the properties of the AC varnish layer 4.

[0024] The ink layer (pattern layer) 5 is composed of multiple inks of different colors, such as cyan, magenta, yellow, black, white, and other special colors (orange, pink, etc.), and by layering these inks, patterns with various colors are created.

[0025] The OP varnish layer 6 is a transparent resin layer provided on the ink layer 5. The OP varnish layer 6 protects the surface of the ink layer 5, and suppresses or prevents the ink layer 5 from rubbing.

[0026] If gravure printing is used, the heat seal layer 3, AC varnish layer 4, ink layer 5 and OP varnish layer 6 are sequentially laminated (printed) by preparing a gravure printing unit for each of these multiple layers (a gravure printing unit for each color for the ink layer 5) and transporting the paper base material 2 sequentially to each gravure printing unit. The gravure printing unit is equipped with a cylindrical gravure plate cylinder with many cells (recesses) formed on its surface and a cylindrical pressure roller facing this, and the varnish, ink, etc. filled in the cells are transferred to the paper base material 2 sandwiched between the gravure plate cylinder and the pressure roller, thereby laminating (printing) the varnish, ink, etc.

[0027] Instead of gravure printing, offset printing, inkjet printing, letterpress printing, screen printing, transfer printing, flexographic printing, and other printing methods may be used.

[0028] In order to reliably prevent the ink layer 5 from penetrating into the paper base material 2 and improve color development, the AC varnish layer 4 is 1 g / m 2 It is preferable to have a layering amount of 1 g / m or more. 2 In order to laminate the above-mentioned AC varnish layer 4, the AC varnish layer 4 may be laminated (printed) onto the paper base material 2 multiple times.

[0029] In addition, by attaching an electrostatic transfer device including a charging bar, a static electricity removal bar, and a power supply unit to the gravure printing unit for printing the ink layer 5, the transfer of the ink from the gravure plate cylinder (cell) of the gravure printing unit to the AC varnish layer 4 may be assisted by electrostatic force (electrostatic printing). This improves the transferability of the ink and improves the printing quality.

[0030] Table 1 shows the print density measurement results for nine types of test specimens (Examples 1-6, Comparative Examples 1-3) of packaging materials 1 (lamination of heat seal layer 3 and OP varnish layer 6 was omitted) created by gravure printing with different ink colors (black or red), with or without AC varnish layer 4, with or without electrostatic printing, and with different numbers of inks (different number of times the ink was printed). For print density measurements, a Videojet X-Rite spectrodensitometer "x-rite" was used, and the density was measured in accordance with ISO13655 and under density status E. It can generally be said that printed materials with high density values ​​have good color development. The paper base material 2 of each test specimen was 70 g / m 2 Each test piece was coated with AC varnish layer 4 at 1g / m 2 The above layers were laminated to standardize the thickness of the AC varnish layer 4 of each test specimen. The density column in Table 1 shows the average density value of five so-called solid areas (areas with no shading) for each of the nine types of test specimens. Nitrocellulose-based color ink was used for the ink layer 5.

[0031] [Table 1]

[0032] The test specimens of Examples 1 to 6 and Comparative Examples 1 to 3 differ in whether or not they have an AC varnish layer 4; the test specimens of Examples 1 to 6 have an AC varnish layer 4, while the test specimens of Comparative Examples 1 to 3 do not have an AC varnish layer 4. Since the test specimens of Comparative Examples 1 to 3 do not have an AC varnish layer 4, an ink layer 5 is laminated on the surface of the paper base material 2. The three test specimens of Comparative Example 1, Example 1, and Example 2 have two types of ink laminated so that a black color appears. The six test specimens of Comparative Examples 2 to 3 and Examples 3 to 6 have a red color appear, and of these, Comparative Examples 2 to 3 and Examples 3 to 4 have one type of ink laminated, and Examples 5 to 6 have two types of ink laminated.

[0033] The differences between Example 1 and Example 2, Example 3 and Example 4, and Example 5 and Example 6 are the presence or absence of electrostatic printing. When the AC varnish layer 4 is laminated, there is no significant difference in the density value whether electrostatic printing is performed (Examples 1, 3, and 5) or not (Examples 2, 4, and 6). It can be seen that electrostatic printing does not contribute significantly to improving density (color development) when the AC varnish layer 4 is used.

[0034] With reference to Example 1 or Example 2 and Comparative Example 1, the density of black color is significantly improved by laminating an AC varnish layer 4. With reference to Example 3 or Example 4 and Comparative Example 2 or Comparative Example 3, the density of red color is also improved by laminating an AC varnish layer 4. With reference to Example 3 or Example 4 and Example 5 or Example 6, the density is also improved by increasing the number of inks.

[0035] Fig. 3 shows an enlarged photograph of the surface of the packaging material of Example 1, and Fig. 4 shows an enlarged photograph of the surface of the packaging material of Comparative Example 1. Note that the paper base material 2 of the packaging material in the photographs shown in Figs. 3 and 4 has a thickness of 65 g / m 2 Coated paper is used.

[0036] 3 and 4, the test specimens with high print density, i.e., the test specimens of Examples 1 to 6 with the AC varnish layer 4 laminated thereon, have a clearly reduced whitish appearance compared to the test specimens of Comparative Examples 1 to 3 without the AC varnish layer 4 laminated thereon. A print quality close to that of printing on a plastic film substrate can be achieved by using the paper substrate 2. [Explanation of symbols]

[0037] 1 Packaging material 2 Paper base material 3 Heat seal layer 4 Anchor coat varnish layer 5 Ink layer (picture layer) 6 Overprint varnish layer 10 packaging bags

Claims

1. paper base material, An anchor coat varnish layer containing a resin and an extender pigment laminated on the surface of the paper base material; and The ink layer is laminated on the surface of the anchor coat layer. Paper print.

2. The anchor coat varnish layer has a composition containing 50 to 91 wt% of vinyl chloride acetate resin, 25 wt% or less of acrylic resin, and 3.0 to 25 wt% of silica-based extender pigment, the total of which is 100 wt%. The paper print according to claim 1 .

3. An adhesive layer is laminated on the back surface of the paper base material. The paper print according to claim 1 .

4. An overprint varnish layer is laminated on the surface of the ink layer. The paper print according to claim 1 .

5. The layer thickness of the anchor coat varnish is 1 g / m ２ That's it. The paper print according to claim 1 .

6. An anchor coat varnish layer containing a resin and an extender pigment is laminated on the surface of the paper base material, An ink layer is laminated on the surface of the anchor coat varnish layer. A method for producing paper printed matter.

7. The anchor coat varnish layer has a composition containing 50 to 91 wt% of vinyl chloride acetate resin, 25 wt% or less of acrylic resin, and 3.0 to 25 wt% of silica-based extender pigment, the total of which is 100 wt%. The method for producing a paper print according to claim 6 .

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