JP4513153B2 - Paper sheet having printability and paper container using the paper sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper sheet having printability having a surface glossiness (hereinafter simply referred to as glossiness) of 60 or more at an incident angle of 60 °, and a paper container in which this paper sheet is assembled.
[0002]
[Prior art]
As a paper sheet used for a paper container having excellent cosmetic properties used for a cosmetic box or the like, a sheet having a glossiness of at least 60, preferably 70 or more has been used.
Thus, as a paper sheet having a surface glossiness of 60 or more, particularly 70 or more, a printing layer is formed on the surface of the paper substrate by ultraviolet curable ink (hereinafter referred to as UV ink), and UV curing is performed on the printing layer. A configuration in which an overcoat layer composed of a mold varnish (hereinafter referred to as UV varnish) is formed is common.
[0003]
As described above, in particular, a paper sheet using UV ink or UV varnish as an overcoat layer has a gloss of 70 or more. However, when recycled, a paper sheet using UV ink or UV varnish is suitable for deinking. Since it is inferior, it is difficult to recycle the paper sheet.
[0004]
In addition, as described above, as a means for increasing the surface glossiness of a paper sheet without using UV varnish, a so-called press coat in which a water-based coating agent is coated and then press processing is performed to form a glossy overcoat layer. The means to do is mentioned.
However, in order to press coat an aqueous coating agent and form an overcoat layer, it is impossible to produce a printed layer and an overcoat layer in-line, and the production rate of the press coat is slow. The production efficiency was poor.
[0005]
On the other hand, when a paper container is manufactured using a paper sheet using UV varnish for the overcoat layer, and printing such as the date of manufacture is applied to the overcoat layer, it is possible to print as it is if it is a laser marker or engraving. .
However, in a method of printing with ink or the like attached to the surface, such as an ink jet printer, thermal printer, or seal, the wet index of the overcoat layer is less than 310 μN / cm, so that the surface cannot be printed as it is. .
[0006]
Accordingly, in order to print with ink or the like attached to the surface, such as an ink jet printer, thermal printer, or seal, a printing portion without an overcoat layer made of UV varnish had to be formed.
Therefore, according to the shape and size of the paper container and the packaging machine, the position and shape of the printed portion had to be determined in advance.
[0007]
[Problems to be solved by the invention]
In view of this, the present invention is a method for printing on an overcoat layer by attaching ink to the surface, such as an ink jet printer, a thermal printer, or a seal, even for a paper sheet having a glossiness of 60 or more. It is an object of the present invention to provide a paper sheet that does not require a print portion and a paper container using the paper sheet.
[0008]
[Means for Solving the Problems]
In the present invention, the surface glossiness at an incident angle of 60 ° is 25 or more, preferably 30 or more, the surface smoothness is 300 seconds or more in the Beck smoothing test, preferably 350 seconds or more, and the thickness is 100 g / The surface glossiness at an incident angle of 60 ° is provided by providing an overcoat layer formed by applying an aqueous coating agent made of an acrylic polymer or a copolymer of acryl and styrene to a paper base material of m ² or more and drying. A paper sheet having printability, having a surface wetting index of not less than 60 and a surface wetting index of not less than 350 μN / cm.
Thus, even with a paper sheet having a glossiness of 60 or more, the surface has a wetting index of 350 μN / cm or more. It is possible to print with ink or the like attached to the surface, such as stamping.
[0009]
The invention according to claim 2 is a paper sheet having printability, wherein a printing layer made of an oil-based ink is provided between the paper base material and an overcoat layer made of an aqueous coating agent.
Thus, even if the printing layer is provided, since oil-based ink is used, it has deinking properties and excellent glossiness.
[0010]
The invention according to claim 3 is a paper sheet having printability, wherein the oil-based ink constituting the print layer is soybean oil.
Since soybean oil is used as the oil-based ink, there is little odor and a good paper sheet can be obtained.
[0011]
The invention according to claim 4 is a paper sheet having printability, wherein the print layer is formed by any one of an offset printing method and a gravure printing method.
[0012]
The invention according to claim 1 is a paper sheet having printability, wherein the thickness of the paper base is 100 g / m ² or more. By setting the thickness of the paper substrate to 100 g / m ² or more, the glossiness of the overcoat layer using the aqueous varnish can be further improved.
[0013]
The invention according to claim 1 is a paper sheet having printability, wherein the paper substrate has a surface glossiness of 25 or more, preferably 30 or more. Further , the paper base material having printability, wherein the paper substrate has a surface smoothness of 300 seconds or more, preferably 350 seconds or more in a Beck smoothing test. Thus, by using a paper substrate having a surface glossiness of 25 or more, the glossiness of a paper sheet provided with an aqueous varnish overcoat layer can be 60 or more. Moreover, the surface glossiness of the paper sheet using an aqueous coating agent can be improved by setting it as 300 seconds or more by the Beck smoothing test of a paper base material.
[0014]
The invention according to claim 1 is a paper sheet having printability, wherein the aqueous coating agent forming the overcoat layer is an acrylic polymer or a copolymer of acrylic and styrene. Thus, application suitability and glossiness can be further improved by using the aqueous coating agent for forming the overcoat layer as an acrylic polymer or a copolymer of acrylic and styrene.
[0015]
The invention according to claim 5 is a paper sheet having printability, characterized in that the viscosity of the aqueous coating agent is 30 seconds or less (measured by # 4 made by Zahn Cup Co.) according to the Zahn cup measurement method. It is.
The invention according to claim 6, the coating amount of the water-based coating agent, characterized in that the range of ^{2g / m 2 ~7g / m 2} , a paper sheet having printability. Thus, by specifying the viscosity and coating amount of the aqueous coating agent, it is possible to obtain a paper sheet that can be uniformly coated, has excellent gloss, and has printability.
[0016]
The invention according to claim 7, the paper sheet having printability according to any one of claims 1 to 6, bent from ruled lines, characterized in that the assembly is a folding carton.
The invention according to claim 8 is a paper container having printability, wherein the paper container is a sack pasting type.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view showing an example of a paper sheet having a printing layer according to the present invention.
The paper sheet of FIG. 1 includes a paper base material 1, a printing layer 2 made of oil-based ink provided on the paper base material 1, an overcoat layer 3 made of an aqueous coating agent provided on the printing layer 2, and an ink. The prints 4 are sequentially provided.
FIG. 2 is an explanatory view showing an example of a paper container in which the paper sheet is punched into a predetermined shape using a punching die, and simultaneously bent from a folding ruled line.
[0018]
Here, the printing layer 2 of the paper sheet is formed by using an oil-based ink by any one of an offset printing method and a gravure printing method. There are few problems and it is preferable.
[0019]
The overcoat layer 3 is not particularly limited as long as an aqueous coating agent is used, but it is preferable to use an acrylic and styrene copolymer or an acrylic polymer.
The aqueous coating agent has a solid content of about 40 to 85% by weight, and adds other wetting agents and surfactants to improve the film suitability. The coating amount of the water-based coating agent is in the range of 2g / m ² ~7g / m ² is preferable from the coating suitability, improved gloss.
As a solvent for dissolving or dispersing these solid contents, it is composed of water and a volatile organic solvent that is partially added. Examples of the added solvent include alcohols such as ethanol, methanol, isopropanol, and n-butanol, acetone, methyl ethyl ketone, and ethyl acetate.
[0020]
A preferable aqueous coating agent used in the present invention does not contain the volatile organic solvent, and includes 5% by weight or less. And it is favorable for application | coating suitability, drying suitability after application | coating, and glossiness to apply | coat as the viscosity of an aqueous coating agent as 30 seconds or less (measured by Zahn Cup company # 4) by the Zahn cup measurement method.
[0021]
Further, as the paper substrate 1, a paper sheet having a glossiness of 60 or more is obtained by setting the glossiness of the surface to 25 or more, and a glossiness of 70 is obtained by setting the glossiness of the surface to 30 or more. The above paper sheet is obtained.
Furthermore, in order to obtain a paper sheet with higher glossiness, it is important to define the smoothness of the paper substrate, and it is preferable to use a paper having a smoothness of 300 seconds or more, preferably 350 seconds or more. .
[0022]
And even if it is the structure which provided the printing layer 2 which consists of oil-based ink, and the overcoat layer 3 which consists of a water-based coating agent on such a paper base material 1, the paper sheet whose glossiness is 60 or more is over This can be achieved even when the coating layer is formed without using the press coating method.
Further, the thickness of the paper base material is not limited, but the paper base material having a thickness of 100 g / m ² or more is more effective, and has strength and rigidity capable of assembling a paper container.
[0023]
Next, the manufacturing method of this invention is demonstrated.
First, a paper sheet is produced by forming a printed layer made of an oil-based ink on the surface of a paper substrate, and then forming an overcoat layer made of an aqueous coating agent having the above composition, followed by drying.
Next, the paper sheet is punched out according to the shape of the paper container using a punching die, and at the same time, a ruled line for bending is provided to manufacture a blank.
[0024]
On the surface of the paper container in which this blank was assembled, the printing 4 was directly applied on the overcoat layer by printing means such as an ink jet printer, a thermal printer, or a seal.
[0025]
This drying is not a convection-type drying method using normal hot air, but a drying method using a combination of near infrared rays and cold air of 40 ° C. or lower. The cold air is not simply a convection method for supplying but a drying method with suction and exhaust according to the supply.
And near infrared rays can dry oil-based ink in a short time by using the thing of a wavelength range of 0.75 micrometer-2.5 micrometers.
[0026]
Then, the paper sheet was punched out according to the shape of the paper container using a punching die, and at the same time, a ruled line for folding was provided to form a blank, and the paper container was assembled by folding the blank from the ruled line.
[0027]
【The invention's effect】
In the present invention, as described above, since the surface of the paper base material is composed of an overcoat layer made of an aqueous coating agent, the surface wettability index is 350 μN / cm or more even in a configuration having a glossiness of 60 or more. On the overcoat layer, ink or the like can be printed on the surface, such as an ink jet printer, thermal printer, or stamp.
[0028]
Furthermore, not only the overcoat layer made of water-based varnish, but also the printing layer uses oil-based ink, so the deinking property is good when the paper container is reused after use, and the paper can be easily recycled. Become.
Moreover, since oil-based ink and water-based coating agent are combined, the drying process time is shortened and the glossiness of the paper container is improved.
Furthermore, in the drying process, not only can the drying time be shortened by using near-infrared rays and cold air of 40 ° C. or lower, but also the problem of shrinkage of the printing layer and the work efficiency of printing due to the increase in the temperature of drying by conventional hot air. Is gone.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a paper sheet forming a paper container of the present invention.
FIG. 2 is a cross-sectional view showing an example of a printed paper container according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Paper base material 2 ... Print layer 3 ... Overcoat layer 4 ... Printing

Claims (8)

The surface glossiness at an incident angle of 60 ° is 25 or more, preferably 30 or more, the surface smoothness is 300 seconds or more in the Beck smoothing test, preferably 350 seconds or more, and the thickness is 100 g / m ² or more. A glossiness of the surface at an incident angle of 60 °, with an overcoat layer formed by applying an aqueous coating agent made of an acrylic polymer or a copolymer of acrylic and styrene to a paper substrate and drying, is 60 or more, A paper sheet having printability, wherein the surface has a wetting index of 350 μN / cm or more.   2. A paper sheet having printability according to claim 1, wherein a printing layer made of an oil-based ink is provided between the paper substrate and an overcoat layer made of an aqueous coating agent.   The paper sheet having printability according to claim 2, wherein the oil-based ink constituting the print layer is soybean oil.   4. The paper sheet having printability according to claim 2, wherein the printing layer is formed by any one of an offset printing method and a gravure printing method. The printability according to any one of claims 1 to 4 , wherein the viscosity of the water-based coating agent is 30 seconds or less (measured by # 4 made by Zahn Cup Co.) according to the Zahn cup measurement method. A paper sheet with. The coating amount of the water-based coating agent, characterized in that the range of ^{2g / m 2 ~7g / m 2} , the paper sheet having printability according to any one of claims 1 to 5. Paper sheet according to any one of claims 1 to 6, bent from ruled lines, characterized in that assembly, paper container having printability. The paper container having printability according to claim 7 , wherein the paper container is of a sack pasting type.

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