JP2014122443A - Method for manufacturing a printed liner or printed corrugated cardboard - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a printed liner or printed corrugated cardboard capable of preserving tactile textures of raw papers and yielding excellent printed ink color development characteristics and printed surface finishes.SOLUTION: In a method for manufacturing a printed liner or printed corrugated cardboard, at least a partial region of the surface of a liner or corrugated cardboard is coated with a treatment liquid including a water-soluble polyvalent metal salt and a cationic thickener and then printed. It is desirable for the coating rate of the water-soluble polyvalent metal salt to be at least 0.15 g/m.

Description

The present invention relates to a method for producing a printing liner or printed cardboard. In particular, the present invention relates to a method for producing a printing liner or printing corrugated cardboard that maintains the texture of the base paper and is excellent in ink color development in printing and finished on the printed surface.

Printing liners or printed cardboards are finally processed into cardboard boxes and used as packaging and transportation packages. Recently, cosmetic printing has been applied to differentiate the content products, and they have an exhibition function. The demand is increasing and high print quality is required. However, when printing on a liner or cardboard, the print quality is a problem due to the low smoothness.
In addition, cosmetic printing may be performed by printing a large amount of white ink on a brown liner and then printing other colors. In the case of such a printing method, it is necessary to print a large amount of expensive ink in order to make the brown liner surface white and improve the finish of other colors such as red and indigo, but when the ink adhesion amount is reduced However, there is a demand for a liner that has a high whiteness in the white ink printing portion and a good finish of other color inks.

As a method for obtaining a liner excellent in printing as described above, a method is disclosed in which a coating agent formed by blending an inorganic pigment, a binder, and a surface sizing agent on the liner surface is applied (Patent Document 1). However, providing the inorganic pigment coating layer on the liner surface has a problem of impairing the uncoated texture inherent in the liner.
On the other hand, a method of applying a water-soluble surface coating agent to the liner surface (Patent Document 2), a method of applying or printing a nonionic water-soluble resin and an aqueous coating agent containing a calcium salt as a dissociable polyvalent metal salt ( Patent Document 3) discloses a method of applying an aqueous composition containing a cationic resin to the surface of a liner or cardboard (Patent Document 4). Although these methods do not cause the problem of impairing the non-coating texture inherent in the liner, satisfactory color development and printed surface finish cannot be obtained, and further improvements are required. It was.
In Patent Document 2, the water-soluble surface coating agent is preferably selected from the group consisting of polyvinyl alcohol, starch, polyacrylamide and styrene-butadiene copolymer, and is exemplified.
In Patent Document 3, it is preferable to use a cellulose derivative or an alkyl ketene dimer as the nonionic water-soluble resin, and calcium formate as the calcium salt, and examples thereof are also exemplified.
Patent Document 4 states that the cationic resin is a polyamine-based resin and that the aqueous composition preferably contains a cationic resin and a polyacrylamide-based resin.

JP-A-2005-89931 JP 2005-200773 A JP2008-31579 JP2007-321307

The present invention relates to a method for producing a printing liner or printed cardboard, and provides a method for producing a printing liner or printed cardboard that maintains the texture of the base paper and is excellent in ink color development and printing surface finish.

As a result of diligent research to solve such problems, the present inventors have found that polyvalent metal salts tend to be excellent as a material for treating the liner surface, and as a result of further research, The present invention has been completed by finding that the problem can be solved by treating with a treatment solution containing a metal salt as a main component and a cationic compound in combination.

The method for producing a printing liner or printed cardboard in the present invention comprises a water-soluble polyvalent metal salt as a main component in at least a partial region of the surface of the liner or cardboard, and further a cationic compound other than the water-soluble polyvalent metal salt It is characterized by printing after applying a treatment liquid containing.
The coating amount of the water-soluble polyvalent metal salt is preferably 0.15 g / m ² or more.
It is preferable to contain 0.2 parts by mass or more of the cationic compound with respect to 100 parts by mass of the water-soluble polyvalent metal salt.
The cationic compound is preferably a cationic polyacrylamide resin.
The cationic compound is preferably a cationic inverse emulsion.
The treatment liquid is preferably applied by flexographic printing.
The printing liner produced according to the present invention may be used for corrugated cardboard.

According to the present invention, it is possible to provide a method for producing a printing liner or printed cardboard that maintains the texture of the base paper and is excellent in ink color development and printing surface.

The method for producing a printing liner or printed cardboard according to the present invention comprises applying a treatment liquid containing a water-soluble polyvalent metal salt and a cationic compound to at least a partial region of the surface of the liner or cardboard, and then performing printing. It is a feature. Details will be described below.

(Water-soluble polyvalent metal salt)
In the method for producing a printing liner or printed cardboard of the present invention, it is important to apply a treatment liquid containing a water-soluble polyvalent metal salt as a main component. By using a water-soluble polyvalent metal salt, ink color development is improved. If printing is performed in an area where water-soluble polyvalent metal salt is attached, the reason for excellent ink color development and print surface finish is not clear, but the polyvalent metal salt and printing ink components present on the surface are not clear. It is thought that this is because some bonding is made to prevent the ink component from penetrating into the base paper. The type of the water-soluble polyvalent metal salt is not particularly limited. Examples thereof include hydrochlorides, sulfates, acetates, formates and the like of polyvalent metals such as aluminum, calcium, magnesium, barium, and zinc. Preferred examples include calcium formate, zinc sulfate, magnesium nitrate, and aluminum sulfate (sulfate band). In addition to using these alone as a water-soluble polyvalent metal salt, two or more may be appropriately selected and used in combination. Among these, use of a sulfuric acid band is preferable because of excellent ink color development.

(Cationic compound)
It is important to use a cationic compound in addition to the water-soluble polyvalent metal salt in the treatment liquid. The use of the cationic compound can improve the coating suitability of the treatment liquid without impairing the ink coloring property of the water-soluble polyvalent metal salt. For this reason, it becomes possible to apply a homogeneous polyvalent metal salt, and excellent printing can be obtained.
The cationic compound is not particularly limited as long as it is a cationic compound other than the water-soluble polyvalent metal salt. For example, a cationically modified compound can also be used. For example, cationic starch, cation-modified polyvinyl alcohol, cationized cellulose, cationic polyacrylamide resins, resins obtained by reacting amines with epihalohydrins (for example, dimethylamine epichlorohydrin resin), cationic vinyl monomers Resin (eg polydiallyldimethylammonium chloride, polyallylamine salt), polyvinylamine resin, polyethyleneimine resin, polyalkylene polyamide resin, polyamide polyurea resin and other cationic resins, cationic emulsion, etc. Is mentioned. These cationic compounds may be used alone or in combination of two or more selected as appropriate. As the cationic compound, a cationic polyacrylamide resin and a cationic reversed-phase emulsion are preferable because they have a high effect of improving coating suitability. The amount of the cationic compound is adjusted depending on the type and combination with the water-soluble polyvalent metal salt to be used, but as a guideline, 0.2 part with respect to 100 parts by mass of the water-soluble polyvalent metal salt. It is preferable to mix the above. Since excessive use may impair the effect of the water-soluble polyvalent metal salt, it is preferably used at 1000 parts or less, more preferably 500 parts or less, and particularly preferably 250 parts or less. Further, the compounding amount of the cationic compound is such that the viscosity of the treatment liquid is Zahn Cup No. It is good to adjust so that it may be 5 to 25 seconds by 4 measured values, Preferably it is 8 to 20 seconds.

(Processing liquid)
In the treatment solution, various starches such as oxidized starch, esterified starch, cold water-soluble starch, enzyme-modified starch, casein, and the like, as long as the effects of the water-soluble polyvalent metal salt and the cationic compound are not impaired. Proteins such as soy protein and synthetic protein, cellulose derivatives such as carboxymethylcellulose and methylcellulose, polyvinyl alcohol and modified products thereof, polyacrylamide resins, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, etc. It is possible to use vinyl polymer latex such as diene polymer latex, acrylic polymer latex, ethylene-vinyl acetate copolymer, etc., and one or more of these can be selected appropriately. Can be used together.

In addition, if necessary, pH adjusters such as dispersants, caustic soda, aqueous ammonia, antifoaming agents, preservatives, fluorescent dyes, mold release agents, dyes, water resistance agents, flow modifiers, thickening water retention agents, coloring Various auxiliary agents such as pigments, dyes, antioxidants, anti-aging agents, ultraviolet absorbers and water repellents may be added as appropriate.
The amount of other materials used together and added is 1000 parts by mass or less, more preferably 500 parts by mass or less, particularly preferably 250 parts by mass or less, with respect to 100 parts by mass of the water-soluble polyvalent metal salt. . When the blending amount of the other material is 1000 parts by mass or more, the ratio of the water-soluble polyvalent metal salt is relatively reduced, so that a desired effect may not be obtained, which is not preferable.

The solid content concentration of the treatment liquid is not particularly limited, and can be set as appropriate in consideration of the drying conditions after application of the treatment liquid, the coating amount, and other factors. %, Preferably 1 to 30% by mass. Even when other materials are used or added together, the above-mentioned solid content concentration is preferable.

The viscosity of the treatment liquid is not particularly limited and can be appropriately set in consideration of the application method of the treatment liquid and other factors. It is preferably 4 to 25 seconds, and particularly preferably 8 to 20 seconds. If the viscosity is in the range of 5 to 25 seconds, it can be uniformly applied onto the liner base paper.
In addition, about the adjustment method of the viscosity of a process liquid, in addition to adjusting the compounding quantity of a cationic compound, it can adjust by adjusting solid content concentration and other materials mentioned above suitably.

The coating amount of the treatment liquid is not particularly limited and can be appropriately set in consideration of the size of the base paper and other factors. Of the treatment liquids, the water-soluble polyvalent metal salt is dried. It is preferable for the coating amount to be 0.15 g / m ² or more because excellent ink color development and a printed surface can be obtained. The upper limit of the coating amount is not particularly limited, but an excessive coating not only saturates the obtained effect but also may adversely affect the uniformity of the printed surface. The dry coating amount is preferably 2.0 g / m ² or less, particularly preferably 0.15 to 1.5 g / m ² .

The coating method of the treatment liquid is not particularly limited, but for example, a rod coater, an air knife coater, a blade coater, a bar coater, a gate roll coater, a roll coater such as a size press, a bill blade coater, a velvapa coater, a spray coater, Ordinary coating apparatuses such as curtain coaters and calendar coatings, and printing presses such as gravure printing and flexographic printing can be used as long as the effects of the present invention are not impaired. As the coating method, it is preferable to use a flexographic printing machine.

When using a coating machine as the coating method for the treatment liquid, the coating machine attached to the paper machine or the coating machine independent of the paper machine may be used, but it comes with the paper machine for productivity reasons. It is preferable to apply with a coating machine.

When using a flexo printing machine as a treatment liquid application method, the flexo printing machine can be divided into three types, stack type, line type, and central impression type, depending on how the printing units are arranged. can do.
When the treatment liquid is applied by a flexographic printing machine, it is preferable that the printing unit for applying the treatment liquid among a plurality of printing units is installed before supplying color ink, that is, at a place where the treatment liquid is first applied to paper. However, in order to further improve the color developability of a specific ink portion, it is possible to install between color ink units.

It is preferable to pass the drying process after applying the treatment liquid. As a drying method, a method of applying cold air or room temperature air to the coated surface, a method of applying hot air using a hot air dryer, a method of irradiating infrared rays using an IR dryer, and the like can be used.

(Processing liquid application area)
In the printing liner or cardboard of the present invention, it is important to apply a treatment liquid containing a water-soluble polyvalent metal salt and a cationic compound to at least a partial region of the liner or cardboard. The application region can be applied to the entire surface of the liner or cardboard, or can be applied to a specific partial region. In particular, according to the effects of the printing liner or printing corrugated board of the present invention, the ink coloring property in printing and the printing surface are affected. Therefore, the treatment liquid is applied only to the region where the printing ink adheres. It is preferable from the viewpoint of resource saving and manufacturing cost reduction.

(Printing method)
The printing liner or printing corrugated board of the present invention is subjected to printing after applying a treatment liquid containing a water-soluble polyvalent metal salt and a cationic compound, but the printing method is not particularly limited. For example, in addition to lithographic printing typified by offset printing, intaglio printing typified by gravure printing, relief printing typified by flexographic printing, etc., screen printing, inkjet printing, toner printing, etc. do not impair the effects of the present invention. Although it can be used in a range, it is particularly preferable to use flexographic printing.
Flexographic printing presses are classified into three types, stack type, line type, and central impression type, depending on how the printing units are arranged, but any type can be used.
In addition, examples of the flexographic ink include alcohol type, cosolvent type, aqueous type, and UV curable type. Among these flexographic inks, the aqueous type is excellent in terms of safety, workability, and economy, Particularly preferred.

(Liner base paper manufacturing method)
The liner base paper used for the printing liner or printing corrugated cardboard of the present invention is not particularly limited as a constituent pulp. For example, one kind or two or more kinds of chemical pulp, mechanical pulp, waste paper pulp and the like are appropriately mixed. Used. Furthermore, a base paper having a multilayer structure formed by combining two or more pulp layers can be used. Further, as the cardboard used in the present invention, those using the above-mentioned liner base paper are used. In addition, sizing agents, paper strength agents, chemical fixing agents, filter media, fillers, dyes, etc., are added to the liner base paper and corrugated cardboard as needed, as long as they do not impair the effects of ink color development and printing surface finish. It can also be added as appropriate.

The paper making method of the liner base paper is not particularly limited, and examples of the wet paper machine include commercial machines such as a round net type paper machine, a short net type paper machine, a long net type paper machine, and a twin wire type paper machine. A paper machine of a scale can be used, and various general paper making methods, which are general liner base paper manufacturing methods, can be appropriately selected and used.
Roller coaters such as rod coaters, air knife coaters, blade coaters, bar coaters, gate roll coaters, size presses, bill blade coaters, velvapa coaters, spray coaters Further, the surface treatment of the base paper can be performed using a normal coating apparatus such as curtain coater or calendar coating, or a printing machine such as gravure printing or flexographic printing.

The materials constituting the surface treatment agent used for the surface treatment of the base paper include inorganic and organic pigments such as kaolin, calcium carbonate, talc, titanium dioxide, synthetic silica, aluminum hydroxide, plastic pigment, polystyrene resin, urea formaldehyde resin, etc. Synthetic polymer fine particles, various latexes such as styrene-butadiene and vinyl acetate-acrylic, various surface strength agents such as polyvinyl alcohol, starch and polyacrylamide, various surface sizing agents such as styrene and olefin, thickeners Various auxiliary agents such as an antifoaming agent, water-proofing agent, mold release agent, and rust preventive agent, and known and publicly used materials used in the production of liner paper can be used as necessary.

As for the liner base paper, there is no problem if the base paper is used for the printing liner or printing corrugated cardboard of the present invention as it is, but before using it, use a machine calendar, soft calendar, super calendar, Yankee dryer, etc. The base paper can be smoothed in advance.

(Cardboard manufacturing method)
The corrugated cardboard used in the printing corrugated cardboard of the present invention is not particularly limited, but generally used is a corrugator machine that is cut into an appropriate size after the liner base paper and the core paper are pasted together. It is done.

(Printing cardboard manufacturing method)
The corrugated cardboard using the printing liner of the present invention is generally cut into an appropriate size into a corrugated cardboard after the printing liner and the core paper are bonded with a corrugator machine. Accordingly, the printed corrugated board of the present invention includes a corrugated board using a printing liner, and a cardboard that has been directly printed. Further, even when printing is further performed on the cardboard using the printing liner of the present invention, the effect is not impaired, and a cardboard having excellent print quality can be provided.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these ranges. In the examples, “parts” and “%” indicate parts by mass and mass% unless otherwise specified.

Example 1
(Preparation of treatment liquid)
100 parts of calcium formate (reagent / Kishida Chemical Co., Ltd.) and 43 parts of cationic polyacrylamide resin (trade name: HG5304 / manufactured by Seiko PMC Co.) are diluted to a solid content concentration of 20%. Got.
(Preparation of printing liner)
For the obtained treatment liquid, the coating amount (solid) is 0.40 g / m ² with respect to the tea liner base paper (density: 0.8 g / cm ³ , rice basis weight: 160 g / m ² , whiteness 15%). Then, it was coated with a wire bar and dried to obtain a treatment liquid coated paper. Thereafter, a white ink (trade name: HW913AQP65F white DM / manufactured by Toyo Ink Co., Ltd.) with a solid content concentration of 35% is applied to the treatment liquid-coated paper so that the coating amount (solid) is 6 g / m ^2. A printing liner was obtained by applying with a bar.

Example 2
A treatment liquid and a print liner were obtained under the same conditions as in Example 1 except that zinc sulfate (reagent / made by Kishida Chemical Co., Ltd.) was used instead of calcium formate in Example 1 as the treatment liquid.
Example 3
A treatment solution and a print liner were obtained under the same conditions as in Example 1 except that magnesium nitrate (reagent / Kishida Chemical Co., Ltd.) was used instead of calcium formate in Example 1 as the treatment solution.

Example 4
A treatment liquid and a printing liner were obtained under the same conditions as in Example 1 except that a sulfuric acid band (trade name: liquid aluminum sulfate / manufactured by Oji Materia Co., Ltd.) was used as the treatment liquid instead of calcium formate in Example 1. It was.
Example 5
As a treatment solution, a cationic reversed phase emulsion (trade name: Somalex SX502C / manufactured by Somar) was used instead of the cationic polyacrylamide resin of Example 4, and 0.8 part was blended with respect to 100 parts of the sulfuric acid band. Except for the above, a treatment liquid and a print liner were obtained under the same conditions as in Example 4.

Example 6
The treatment was performed under the same conditions as in Example 4 except that cationized starch (trade name: manufactured by Pillar P3Y / PIRAAB STARCH Co. Ltd) was used instead of the cationic polyacrylamide resin of Example 4. A liquid and a print liner were obtained.

Example 7
Except that the treatment liquid obtained in Example 4 was applied to the tea liner base paper with a wire bar so that the coating amount (solid) was 0.20 g / m ² and dried, all the same as in Example 4. Under conditions, a print liner was obtained.
Example 8
As a treatment liquid, a cationic reversed-phase emulsion (trade name: Somalex SX503C / manufactured by Somar) was used instead of the cationic polyacrylamide resin of Example 4, and 0.1 part was added to 100 parts of the sulfuric acid band. Except for the above, a treatment liquid and a print liner were obtained under the same conditions as in Example 4.

Comparative Example 1
Except that 100 parts of a water-soluble modified polyamine resin (trade name: DK6852 / Seiko PMC) and 18 parts of a cationic polyacrylamide resin were added to the treatment liquid, the same conditions as in Example 1 were used. A treatment liquid and a printing liner were obtained.
Comparative Example 2
As the treatment liquid, an anionic reverse phase emulsion (trade name: Somalex 530 / manufactured by Somar) was used instead of the cationic reverse phase emulsion of Example 8, but there was no compatibility between the sulfuric acid band and the anionic reverse phase emulsion. The treatment liquid could not be obtained.

Comparative Example 3
A treatment liquid and a print liner were obtained under the same conditions as in Example 1 except that a sulfuric acid band was used alone as the treatment liquid.

Comparative Example 4
A printing liner was obtained under the same conditions as in Example 1 except that the treatment liquid was not applied.

The following evaluation was performed on the obtained treatment liquid and printing liner, and the obtained results are shown in Table 1.

"Viscosity of treatment liquid"
The viscosity of the treatment liquid having a solid content concentration of 20% was measured by the following method (Zahn cup method).
In a treatment liquid kept at 25 ° C., Zahn cup No. 4 having an orifice diameter of 4 mm was used. 4 is submerged, and the submerged cup is quickly pulled up by a certain operation, and the time from the moment when the bottom surface of the cup is separated from the liquid surface until the flow of the processing liquid flowing out from the orifice is interrupted is measured.

"Ink coloring"
The ink coloring property of the printing liner was visually evaluated as follows.
◎: Excellent ink color development and good print finish ○: Slightly good ink color development and slightly good print finish △: Slightly poor ink color development and slightly poor print finish ×: Ink color development Inferior, poor print finish

“Applicability”
The coating suitability when the treatment liquid was applied to a flexographic printing machine and a bar coating machine was evaluated as follows based on the viscosity measurement results and the like.
○: Excellent application suitability (viscosity 8 to 20 seconds)
Δ: Applicability is slightly superior (viscosity 7 to 25 seconds)
X: Applicability is slightly inferior (viscosity 6 seconds or less), or application is impossible (processing liquid could not be obtained)

In any of the examples, by applying a treatment liquid containing a water-soluble polyvalent metal salt and a cationic thickener as defined in the present invention, a print liner having excellent ink color development and good print finish can be obtained. It was.

Claims (6)

Printing is performed after applying a treatment liquid containing a water-soluble polyvalent metal salt as a main component and a cationic compound other than the water-soluble polyvalent metal salt to at least a partial region of the liner or cardboard surface. A method for producing a printing liner or printed cardboard. The method for producing a printing liner or printed cardboard according to claim 1, wherein the coating amount of the water-soluble polyvalent metal salt is 0.15 g / m ² or more. The manufacturing method of the printing liner or printing corrugated board of Claim 1 or 2 which apply | coats the process liquid containing 0.2 mass part or more of cationic compounds with respect to 100 mass parts of water-soluble polyvalent metal salt. The method for producing a printing liner or printed cardboard according to any one of claims 1 to 3, wherein the cationic compound is a cationic polyacrylamide resin. The method for producing a printing liner or printed cardboard according to any one of claims 1 to 3, wherein the cationic compound is a cationic inverse emulsion. The method for producing a printing liner or printed cardboard according to any one of claims 1 to 5, wherein the treatment liquid is applied by flexographic printing.