JP2009012277A - Manufacturing method of printed matter of corrugated cardboard, and printed matter of corrugated cardboard obtained by this method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply manufacturing printed matter excellent in makeup properties, by preventing staining and blurring of the printed matter due to insufficiency of the cohesion of an ink film in the case of printing by using an inkjet printing method so as to respond to small lots and many kinds or in the case of utilizing paper manufactured by recycling repeated in many times. <P>SOLUTION: The manufacturing method of the printed matter of a corrugated cardboard includes the process that an abrasion resistance giving agent which contains 10-50 mass% of an emulsion resin having a glass transition temperature of -50-50°C as a solid content is applied by spraying on the printing surface of a printing base for the corrugated cardboard immediately after ink is printed on the surface, so that the amount of coating with the agent is 0.1-20 g/m<SP>2</SP>in conversion to the solid content. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for producing a corrugated cardboard printed matter, and more specifically, in response to the recent use of paper manufactured by repeating a small lot, a variety of products and a large number of reproductions in the corrugated cardboard industry, The present invention relates to a method for producing a corrugated cardboard printed product that can more easily produce a printed product without blur.

Traditionally, the trend of the corrugated cardboard printing industry has been further progressing in small lots and multiple varieties, and a printing method that can print many printing designs in a shorter time than the conventional method of printing the same printing designs fixedly. There is an urgent need to change. Therefore, digital data of a print image designed by a personal computer can be printed directly on paper without using a printing plate, and generally the basic colors of yellow, red, indigo and black, or their light colors In addition, an ink jet printing method for printing with ink of a fixed hue has been attracting attention.

Using an inkjet printing method eliminates the need for plate change and ink change as in conventional printing, and the more printing lots and the variety of products are advanced, the more advantageous it is that time loss and labor can be reduced. . Furthermore, since this printing method can form dots up to several thousand dpi, it is possible to easily obtain a high-definition printed matter. Therefore, the inkjet printing method is expected to further expand the range of use in the field of corrugated cardboard printing from the viewpoint of improving both printing efficiency and quality.

However, even an ink jet printing method having many advantages has a problem that must be solved in practice. For example, in personal use such as photographic prints, first, vivid color development is required, so dyes are used as coloring materials. However, corrugated cardboard as a packaging material is exposed to harsh outdoor environments, so it is light resistant. Low dyes are not suitable. Furthermore, even when it gets wet in the rain, it is necessary that the printed surface does not bleed and no other color transfer occurs. Therefore, there is a demand for an ink of a type using a pigment having high light resistance and insoluble in water as a color material.

In general, ink droplets supplied by inkjet printing form a thin printed film compared to normal flexographic printing, so it is necessary to contain more pigment to maintain the coloring power of the printed matter. is there. However, in the ink jet printing method, the ink must maintain a low viscosity so that it can be ejected from the nozzle, and an increase in the total solid content that leads to an increase in the ink viscosity is suppressed. In this case, when a large amount of pigment is contained, a prescription for reducing the other solid content as much as possible is required, and the resin component as the other main solid content is reduced.

In addition, the ink used in the ink jet printing method is required to reduce the resin component from another point of view in addition to the above reasons. When low-viscosity ink is printed on highly penetrable paper such as cardboard, the ink penetrates deep into the paper, causing bleeding and fading. In particular, when a resin component having a high affinity with the dispersion medium is contained in the ink, the dispersion medium is less likely to be detached from the ink system and the drying property is lowered, so that the above-described bleeding and fading are likely to occur.

Therefore, the ink-jet ink using a pigment as a coloring material has a blending design that inevitably reduces the resin component that serves as a binder, both in terms of ink viscosity and drying properties. However, if the resin component serving as the binder is reduced, it becomes difficult to maintain the cohesive strength of the ink film, and there arises a problem that the friction resistance is lowered.

As described above, in order to obtain a printed matter that does not bleed or fade with highly penetrable paper using a low-viscosity ink in the ink jet printing method, the ink colorant component does not penetrate into the paper, and the paper It is necessary to leave a large amount on the surface. From such a point of view, after applying a reaction liquid that forms an agglomerated film when reacted with the pigment ink by an ink jet printing method in advance, the pigment ink is printed, so that the color material component of the ink stays on the paper surface. A method has been proposed (for example, Patent Document 1).

However, when this method is used, an ink film having a poor film cohesive force as described above is formed in a state of being exposed on the paper surface. Therefore, as a result, when the printed matter of the corrugated cardboard sheet is manufactured by using the ink jet printing method, the problem that the printed surface is rubbed when the sheets overlap with each other causes problems such as fouling and blurring. In addition, when printing on a cardboard liner and printing with a preprinting method in which cardboard is formed later, an ink film is removed when the printing surface comes into contact with a guide roller or the like. There was a problem that occurred.

By the way, another trend in the corrugated cardboard printing industry is environment-friendly and resource-saving. As part of this trend, recycled paper is used. In the corrugated cardboard industry, however, the number of times of recycling tends to increase. The paper produced by repeating such reproduction a number of times is characterized in that the fibers are short and the printing ink is more easily penetrated. Then, even in printing on such a paper, a method for preventing bleeding and fading by keeping the printing ink on the surface of the paper is required.

Even in the flexographic printing system used for normal cardboard printing, in order to keep the ink on the surface of the paper, the ink is made highly viscous by setting the pigment concentration high and then quickly removing the solvent component from the printing ink. It is necessary to keep the solid content of the paper on the paper surface. Therefore, as described above, if the method of reducing the amount of the binder resin having a high affinity for the solvent component is taken, an ink film with poor film cohesion is exposed on the surface of the paper, similar to the ink jet printing method. Will be. Therefore, in order to perform printing with high cosmetics on paper that is frequently recycled, the use of ink with a small amount of resin as a binder can be considered as a simpler means, but a device that further improves the cohesive strength of the ink film. Is required.
JP 2004-249725 A

Therefore, the problem to be solved by the present invention is when printing using an ink-jet printing method in order to cope with small lots and multi-product types, or when using paper manufactured by repeating many times of reproduction, etc. The present invention is to provide a method for easily producing a printed material having excellent cosmetic properties by preventing the printed material from being soiled or blurred due to insufficient cohesive strength of the ink film.

Using ink used in inkjet printing, which is considered a promising printing method for dealing with small lots and many types of cardboard printing, and ink printed on paper that has been repeatedly regenerated many times In the case of printing, particularly when the ink coloring material is sufficiently retained on the paper surface, even if the printed surface is rubbed with another printed material or a roller, stains and blurring occur.

Therefore, as a result of intensive investigations to improve the friction resistance and make a highly practical printed material, the present inventors utilize a spray method before another printed material or roller contacts the printed surface, The present invention has been completed by finding that all of the above problems can be solved by applying a specific amount of an antifriction agent containing an emulsion resin having a specific glass transition temperature.

That is, the present invention is (1) a friction resistance containing 10 to 50% by mass of an emulsion resin having a glass transition temperature of −50 to 50 ° C. as a solid content on a printing surface immediately after printing ink on a corrugated board printing substrate. The present invention relates to a method for producing a corrugated cardboard printed matter comprising a step of applying a property imparting agent by a spray method so as to have an application amount of 0.1 to 20 g / m ^{2 in} terms of solid content.
Here, the “friction resistance imparting agent containing 10 to 50% by mass of emulsion resin as solid content” means that emulsion resin is usually present in a dispersed state as resin particles in a dispersion medium. Only (solid content) refers to a state of being contained in the friction resistance-imparting agent in an amount of 10 to 50% by mass.
Further, the "applied so that the coating amount of 0.1 to 20 g / m ² in terms of solid content of the emulsion resin", when applied to friction resistance imparting agent, per coated surface 1 m ^2, 0. A state in which 1 to 20 g of emulsion resin particles (solid content) are present.
For example, in the case of a friction resistance imparting agent composed of 50% by mass of emulsion resin particles, 80% by mass of an aqueous resin emulsion containing 50% by mass of a dispersion medium, and 20% by mass of other components, the emulsion resin is used as a solid content. , 50 × 0.8 = 40 (% by mass). Then, if the friction resistance imparting agent is applied at 5 g / m ^2, in terms of solid content of the emulsion resin, to being coated at a coverage of 5 × 0.4 = 2 (g / m 2) Become.
The present invention also relates to (2) a method for producing a corrugated cardboard printed matter as described in (1) above, wherein ink is printed by an ink jet printing method.
The present invention also relates to (3) a method for producing a corrugated board printed matter according to the above item (1) or (2), wherein an ink further containing a pigment is printed.
The present invention also relates to (4) a corrugated cardboard printed matter obtained by the method for producing a corrugated cardboard printed matter described in any one of (1) to (3) above.
Hereinafter, the present invention will be described in more detail.

The purpose of the present invention is to prevent the occurrence of fouling and scumming due to insufficient cohesive force of the ink film when a solid material such as a roller or other printed material comes into contact with the printing surface. A method for producing a corrugated cardboard printed material, wherein a material that improves friction resistance is applied by a non-contact method called spraying before the solid material comes into contact. Here, by reducing as much as possible polymer materials having high affinity with the dispersion medium, such as pigment dispersant and binder resin in the ink, the penetration of the coloring component into the paper as the base material is prevented and the surface stays on the surface. Such a purpose can be effectively achieved by adopting the method of making the images.

The manufacturing method of this invention includes the process of apply | coating a friction-resistance imparting agent to the printing surface immediately after printing ink on the printing base material for corrugated cardboard.
As the printing method and ink used in the present invention (printing of ink onto the above-mentioned corrugated board printing substrate), first, an ink jet printing method for achieving the purpose of obtaining a small lot and various kinds of corrugated printed matter, A combination of inkjet ink compositions using a pigment as a colorant is preferred. In addition, in order to obtain a paper corrugated printed matter manufactured by repeating many times of reproduction, a combination of an ordinary flexographic printing method and an ink composition using a pigment as a coloring material is preferable in addition to the inkjet printing method described above. is there.

The ink jet printing method is a method of forming an image by ejecting ink from nozzles. In order to eject ink, a method using a piezoelectric element such as piezo, a method using pressure due to ink vaporization, etc. can be used. It is. Further, an on-demand method in which ink droplets are intermittently ejected according to a printed image may be used, or a continuous method in which only droplets necessary for image formation are landed on a substrate by continuous ejection. . On the other hand, the flexographic printing method is a printing method that uses a rubber-like relief plate, and has a feature that even if the printing surface has irregularities such as corrugated cardboard, the irregularity of the plate becomes good.

The ink used in the inkjet printing method and flexographic printing is an ordinary ink in which each color pigment having good light resistance and insoluble in water is used as a color material, and the pigment is dispersed in an aqueous medium with various pigment dispersants. Ink compositions can be used.

Here, as the pigment, organic and inorganic color pigments, which are usually used in inks for ink jet printing and flexographic printing, can be used, and organic pigments having particularly clear color developability and low specific gravity are used. Is preferred. The ink jet printing method is characterized by small droplets, and high-definition printing is possible. However, in order to obtain a high-density one, it is necessary to set the pigment concentration in the ink high. On the other hand, as the pigment concentration increases, the viscosity also increases. Therefore, it is important to balance the coloring power and the viscosity. In general, an inorganic pigment having a large specific gravity has a specific gravity of 5 to 30% by mass in the ink composition. In the case of an organic pigment having a small size, the ink composition preferably contains about 2 to 20% by mass. On the other hand, the flexographic printing method has a higher degree of freedom in ink viscosity than the ink jet printing method. In order to prevent penetration of the printing substrate into the paper, high solid differentiation is advantageous. Therefore, in the case of an ink composition for flexographic printing, an inorganic pigment having a large specific gravity is 10 to 40 mass in the ink composition. %, An organic pigment having a small specific gravity is preferably contained in the ink composition in an amount of about 4 to 30% by mass.

Next, examples of the pigment dispersant include acrylic acid-based, styrene-acrylic acid-based, styrene-maleic acid-based, styrene-acrylic acid-maleic acid-based monomers, which include an acid group-containing monomer and an acid group-free monomer. Polymeric pigment dispersants such as a copolymer resin obtained by copolymerizing, a polyurethane resin having an acid group in the molecule, and a polyester resin having an acid group in the molecule can be used. Such a polymer type pigment dispersant preferably has an acid value of 50 to 250 mgKOH / g, is soluble in an aqueous medium in the presence of a basic compound, and increases the cohesive strength of the ink film. It is suitable because it also acts as a binder resin. Furthermore, as other pigment dispersants, various surfactants generally known as pigment dispersants can be used.

Paper used as a corrugated cardboard printing substrate has a lower density of paper fibers and is likely to penetrate as compared with ordinary ink jet recording paper. The same can be said for paper manufactured by repeating the reproduction a number of times. Therefore, in both inks for inkjet printing and inks for flexographic printing, the content of polymer materials (pigment dispersants, etc.) that have a high affinity with aqueous media and slow the separation of aqueous media from ink compositions is minimized. It is preferable. From such a viewpoint, the content ratio between the pigment and the polymer material in the ink for ink jet printing used in the present invention is approximately pigment: polymer material = 10: 0.5 to 10: 5 as a mass ratio. It is preferable that

On the other hand, as described above, the ink viscosity is not limited as compared with the ink-jet printing method, and even in the flexographic printing method capable of achieving high solid differentiation advantageous for drying, printing is performed on paper produced by repeated reproduction many times. When the flexographic ink is used in the present invention, the content ratio of the pigment and the polymer material in the ink is approximately pigment: polymer material = 10: 1 to 10: 5 as a mass ratio. More preferably.

For example, in the case of ink for ink jet printing, a polymer dispersant having an acid group is used as a pigment dispersant, and a pigment is aggregated by using a reaction liquid containing a polyvalent metal ion. In Patent Document 1 showing a technique for obtaining high fixability, the content ratio of the pigment to the polymer dispersant in the ink composition is specifically exemplified in Examples, and the pigment: polymer dispersant is used as the mass ratio. = 10: 1.5 (pigment ink K1, pigment ink B1, pigment ink M1, pigment ink Y1). In the ink composition exemplified in Patent Document 1, the component of the binder resin that develops the cohesive strength of the ink film when dried is only a polymer material used as a pigment dispersant. Therefore, with such a ratio of pigment to polymer material, even if the pigment aggregates quickly, the cohesive strength of the film becomes weak and the friction resistance becomes low unless a friction resistance imparting agent is applied as in the present invention. Extremely low.

Next, as the aqueous medium, usually, ink for ink jet printing or flexographic printing in which water and, if necessary, various water-miscible organic solvents for adding functions such as wettability and dryness are added and mixed. Aqueous media that are used in inks can be used. Examples of water-miscible organic solvents include lower alcohols such as methanol, ethanol, and propanol; polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and glycerin and derivatives thereof; methyl acetate, ethyl acetate, and lactic acid. Ester solvents such as methyl and ethyl lactate; ketone solvents such as acetone are preferred.

In addition, aqueous emulsion resin (improving the cohesive strength of the ink film) and lubricant (reducing frictional force) to improve friction resistance within the allowable range of ink viscosity, and leveling agent to improve printability, Various additives such as a wetting agent may be included.

The ink used in the present invention is prepared by, for example, mixing a pigment, a polymer material (pigment dispersant, etc.), an aqueous medium, and other additives as necessary, using a disperser and a kneader. It can be performed according to conventional methods.

In the present invention, after the ink is printed, a step of applying a friction resistance-imparting agent to the printing surface is performed in order to mainly improve the friction resistance. In the present invention, a coating having high friction resistance can be formed on the printing surface of the corrugated board substrate by applying a friction resistance imparting agent containing an emulsion resin to be described later on the printing surface. Even if the printed matter, the roller, or the like comes into contact, it is possible to satisfactorily prevent the printed surface from being stained or damaged.

The friction resistance imparting agent used in the present invention contains 10 to 50% by mass of an emulsion resin having a glass transition temperature of −50 to 50 ° C. as a solid content. Since the emulsion resin is in the form of particles in the dispersion medium, a high resin solids dispersion (friction resistance imparting agent) can be obtained even when the viscosity is sufficiently low for spraying by a spray method or the like. Further, after drying, the above-mentioned soft resin having a glass transition temperature can be formed into a film having a friction resistance.

The glass transition temperature (Tg) here is a theoretical value obtained by an approximate expression of wood of the following formula.
1 / Tg = (W1 / T1) + (W2 / T2) + (W3 / T3) +
(Wherein Tg represents the glass transition temperature (absolute temperature) of the emulsion resin, W1, W2, W3... Represent the mass fraction of the monomer used as the polymerization component of the emulsion resin, and T1, T2 , T3... Indicate the glass transition temperature (absolute temperature) of a single polymer composed of the monomer).

Specifically usable emulsion resins include acrylic emulsion resins, styrene-acrylic emulsion resins, ethylene-vinyl acetate emulsion resins, styrene-diene synthetic rubber latex, vinyl acetate emulsion resins, polyurethane emulsion resins, and polyolefins. -Based emulsion resin, polyester-based emulsion resin, polyamide-based emulsion resin, polybutene-based emulsion resin, and the like. Of these, acrylic emulsion resins, styrene-acrylic emulsion resins, and ethylene-vinyl acetate emulsions are preferred. In this case, the effect of the present invention can be obtained satisfactorily.

Furthermore, as a polymerization component for synthesizing the above acrylic emulsion resin and styrene-acrylic emulsion resin, (meth) acrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate , Alkyl (meth) acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, aralkyl (meth) acrylates such as benzyl methacrylate, benzyl acrylate, butoxyethyl methacrylate, butoxyethyl acrylate Alkoxyalkyl (meth) acrylates such as diethylene glycol monoethyl acetate (Meth) acrylic esters of polyalkylene glycol monoalkyl ethers such as triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, hydroxyl groups such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate (meth) Acrylic monomers such as acrylates, glycidyl (meth) acrylate, and epoxy group-containing (meth) acrylates such as methyl glycidyl (meth) acrylate; styrene, α-methylstyrene, o, m, p-chlorostyrene, vinyl Mention may be made of styrene monomers such as toluene. Examples of the polymerization component for synthesizing the styrene-diene synthetic rubber latex include the styrene monomer, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3- Mention may be made of diene monomers such as pentadiene and 2-methyl-1,3-pentadiene. The above monomers are polymerized by an ordinary emulsion polymerization method alone or in combination of two or more thereof so that the glass transition temperature of the polymer becomes -50 to 50 ° C. to obtain an emulsion resin. Can do. The dispersant used for the emulsion polymerization is not particularly limited, and anionic surfactants, nonionic surfactants, alkali-soluble water-soluble resins having a dispersion protecting ability for polymer particles, and the like having a surface active action of a polymer, etc. Can be mentioned.

In the friction resistance imparting agent used in the present invention, when the glass transition temperature of the emulsion resin is lower than −50 ° C., there is a possibility that the contact surface between the obtained printed materials may cause adhesion (blocking), and 50 ° C. If it is higher, a friction resistant film may not be obtained, which is not preferable. From such a viewpoint, in order to always obtain a good printed matter, the glass transition temperature of a suitable emulsion resin is −30 to 30 ° C.

Furthermore, the content of the emulsion resin contained in the friction resistance-imparting agent is 10 to 50% by mass as a solid content. When the content of the emulsion resin is less than 10% by mass, a large amount of coating is required to obtain a friction-resistant film, and the printed surface is soaked that the printed matter is oozed, and extra time is required for drying. Problems such as requiring heat energy occur. On the other hand, if it exceeds 50% by mass, the friction resistance-imparting agent itself has a high viscosity, which makes it difficult to apply by spraying and also causes problems such as drying and the tendency to clog the spraying device.

In addition, Tg-50-50 degreeC emulsion resin becomes a component which has film formability in a normal application environment, and since there is not much difference in a density by the kind (material) of resin, when apply | coating the same quantity, It is considered that a film having the same thickness is formed. Furthermore, the durability of the film necessary for imparting friction resistance is not significantly different among the materials. Therefore, if an emulsion resin having a Tg in the above range is used, it is presumed that the same effect can be obtained regardless of the type of resin (polymer material).

As a method for producing a printed matter using the above ink composition and friction resistance-imparting agent, first, a corrugated cardboard printing base such as a corrugated cardboard sheet that has already been processed into a sheet shape or a corrugated paper liner before being processed is used. The ink composition is printed on the material by various printing methods such as an ink jet printing method or a flexographic printing method. Further, at the time of printing, in order to agglomerate the solid content of the ink composition, a reaction liquid containing a polyvalent cation such as a polyvalent metal ion or polyamine may be first impregnated in the paper. .

In the case of a printed corrugated cardboard sheet, a corrugated cardboard box is obtained through a punching process for processing into a box and a gluing box making process. Thereafter, the printed materials are stacked and stored. However, when the cohesive force of the ink composition film is low, the printed materials are stained or damaged due to friction when the printed materials are stacked.
On the other hand, when printing on a corrugated paper liner, the core and the back liner are then glued together to form a corrugated cardboard sheet. At this time, the printing surface comes into contact with a guide roller and a hot plate for drying the glue. . Also, usually, if the heat resistance of the ink composition is not sufficient, the ink may be taken on the thermal plate when it comes into contact with the thermal plate, and may be soiled. In such a case, an overprint varnish for imparting heat resistance ( OP varnish) is applied by a roller coating method. Accordingly, here too, if the cohesive force of the ink composition film is low, the printed matter is soiled and / or smudged when it comes into contact with the guide roller, hot plate, and OP varnish application roller.

Therefore, in the present invention, a printed material having high friction resistance is obtained by applying a friction resistance imparting agent to the printing surface by a spraying method (a spraying device) immediately after printing. Here, “immediately after printing” in the present invention refers to a period from the end of printing to before the printing surface comes into contact with another solid material such as another roller or printed material.

As a spraying method (spraying device) in the present invention, any of general spraying devices that spray mist droplets can be used. First, a simple air gun spray type, airless spray type, slit Various types of sprays such as types can be suitably used. Furthermore, when printing is performed by the inkjet printing method, the friction resistance imparting agent may be applied by the inkjet method from the same inkjet head or another head, or may be applied using another spray spraying device or the like. Good.

The coating amount of the friction resistance imparting agent is preferably 0.1 to 20 g / m ² in terms of the solid content of the emulsion resin contained as a material. If the coating amount is less than 0.1 g / m ^2, it is difficult to obtain good friction resistance. On the other hand, if it exceeds 20 g / m ² , blocking is likely to occur, which is not preferable. From such a viewpoint, in order to always obtain a good printed matter, the coating amount of a more suitable friction resistance imparting agent is 0.5 to 10 g / m ² in terms of the solid content of the emulsion resin contained as a material. It is.

By using the present invention, even if an inkjet printing method is used, it is possible to obtain a good corrugated printed matter that has sufficient friction resistance and is free from fouling and blurring. The same applies to the case of using paper that has been recycled many times. This type of corrugated cardboard printed material production method is particularly compatible with the recent trends in the corrugated cardboard printing industry, which are compatible with small lots, multi-product types, environmental friendliness, and resource-saving paper. is there. The obtained corrugated cardboard printed matter is a more beautiful printed matter with no fouling or blurring on the printed surface.

When the present invention is used, the ink film is agglomerated in the case of printing using an ink jet printing method in order to cope with a small lot and a variety of products, or in the case of using paper manufactured by repeating many times of reproduction. It is possible to prevent the printed matter from being stained or damaged due to insufficient power, and to easily produce a printed matter having excellent cosmetic properties.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, “%” means “% by mass”, and “part” means “part by mass”.

Examples 1-12 and Comparative Examples 1-8
<Preparation of aqueous resin varnish A>
Neutralization of 300 parts by mass of acrylic copolymer resin (monomer composition; methacrylic acid / methyl methacrylate / stearyl methacrylate = 15/75/10, acid value 68 mgKOH / g, weight average molecular weight about 11,000) An amount of triethanolamine dissolved in 700 parts by mass of water was dissolved by heating at 80 ° C. to prepare an aqueous resin varnish A having a solid content of 30% by mass.

<Preparation of aqueous resin varnish B>
300 parts by mass of styrene-acrylic copolymer resin (monomer composition; methacrylic acid / methyl methacrylate / butyl methacrylate / styrene = 25/25/10/40, acid value 113 mgKOH / g, weight average molecular weight about 23,000) Was added to 700 parts by mass of water in which triethanolamine in an amount neutralized with respect to the resin was dissolved, and heated and dissolved at 80 ° C. to prepare an aqueous resin varnish B having a solid content of 30% by mass.

<Preparation of ink for inkjet printing>
Carbon black (trade name: Printex 80, manufactured by Degussa) 5 parts by mass, aqueous resin varnish A 5 parts by mass, and 10 parts by mass of water were stirred and mixed, and further kneaded using a bead mill, then 10 parts by mass of glycerin, water 70 parts by mass was added and mixed to prepare an ink for inkjet printing. The mass ratio of the pigment and the resin solid content in this ink is 5: 1.5, and the content of the resin solid content is suppressed to a low ratio so that the ink tends to stay on the paper surface.

<Preparation of ink for flexographic printing>
10 parts by mass of carbon black (trade name: MA-100, manufactured by Mitsubishi Chemical Corporation), 15 parts by mass of aqueous resin varnish B, and 10 parts by mass of water were stirred and mixed, and further kneaded using a bead mill, and then 5 parts by mass of isopropanol, 60 parts by mass of water was added and mixed to prepare a flexographic ink. The mass ratio of the pigment and the resin solid content in this ink is 10: 4.5, and the content of the resin solid content is suppressed to a low ratio so that the ink tends to stay on the paper surface.

<Preparation of antifriction agent>
The emulsion resin described in Table 2 was diluted with water until a predetermined concentration (concentration shown in Table 1) was obtained to prepare a friction resistance imparting agent.

Creation of printed materials <Inkjet printing>
The ink jet printing ink prepared by the above method was applied to a K liner (made by Oji Paper Co., Ltd., basis weight 140 g / m ² ) with a piezoelectric inkjet printer (trade name: PX-V600, manufactured by Seiko Epson Corporation). A strip-like image having a thickness of 1 cm was printed.

<Flexo printing>
Using a hand proofer (165 line), apply the paper to the lower liner (trade name: ETS160 (manufactured by Rengo Co., Ltd.)) so as to obtain a 1 cm strip-shaped print, and use the flexographic ink prepared by the above method. A belt-like image having a thickness of 1 cm was printed.

<Application of friction resistance imparting agent>
[Application by spraying device]
(Setting application conditions)
Using an air gun type spraying device that moved 1.5 m at a constant speed, each friction resistance-imparting agent was sprayed onto a K liner having a width of 25 cm while changing the degree of opening and closing of the nozzle at a constant air pressure. The amount of increase in the mass of the K liner after spraying was used as the spray amount, and the relationship between the degree of opening and closing of the nozzle and the spray amount was graphed, and the application amount conditions were set in advance.
(Coating operation)
According to the conditions obtained from the above method, the degree of opening and closing of the nozzle is set so that the predetermined application amount of each friction resistance imparting agent (the application amount shown in Table 1) is set, and the friction resistance imparting agent is printed. The surface was sprayed to obtain a printed / coated material.

<Evaluation test and evaluation criteria>
The following evaluation was performed and the results are shown in Table 1.
(1) Sprayability The state of droplets and nozzle clogging after spraying were visually evaluated when the antifriction agent was sprayed with an air gun type spraying device.
(Evaluation criteria)
3: The droplets are mist-like and can be applied uniformly, and the nozzles are not clogged at all.
2: Although the liquid droplets are large and small, they can be applied uniformly and the nozzles are not clogged at all.
1: Large droplets cannot be uniformly applied, and clogging is observed at the nozzle.

(2) Friction resistance (i) Printed material obtained by ink jet printing method 2.5 cm x 25 cm A sample piece containing a printed part at the center is cut using a Gakushin type friction resistance tester. The same paper used for printing was used, and the friction resistance was evaluated from the number of times the printed portion was stained when rubbed 100 times at a time with a load of 500 g.
(Evaluation criteria)
5: The printed part is not stained at all after 500 times of friction.
4: The printed part is not soiled by 400 times of friction, but is soiled by 500 times of friction.
3: The printed portion is not soiled by 300 times of friction, but is soiled by 400 times of friction.
2: The printed part is not soiled by 200 times of friction, but is soiled by 300 times of friction.
1: The printed part is soiled by friction up to 200 times.
(Ii) A printed piece obtained by flexographic printing was cut into 2.5 cm × 25 cm, and a sample piece including a printed part in the center was used for printing using a Gakushin type anti-friction tester. The friction resistance was evaluated from the number of rubbing times when the printed portion was stained when the load was rubbed under a load of 500 g.
(Evaluation criteria)
5: The printed part is not stained at all by 100 times of friction.
4: The printed part is not soiled by 90 times of friction, but is soiled by 100 times of friction.
3: The printed part is not soiled by 80 times of friction, but is soiled by 90 times of friction.
2: The printed portion is not soiled by 70 times of friction, but is soiled by 80 times of friction.
1: The printed part is soiled by friction up to 70 times.

(3) Water and friction resistance A sample piece including a printed part at the center section cut to 2.5 cm × 25 cm is wetted with water as a cotton cloth using a Gakushin type friction resistance tester, and 200 g The water rub resistance was evaluated from the number of rubs when the printed part began to get dirty when rubbed twice at a time with a load.
5: The printed part is not stained at all by 10 times of friction.
4: The printed part is not soiled by 8 frictions, but is soiled by 10 frictions.
3: The printed part is not soiled by 6 frictions, but is soiled by 8 frictions.
2: The printed part is not soiled by 4 times of friction, but is soiled by 6 times of friction.
1: The printed part is stained by up to 4 times of friction.

(4) Blocking properties The coated surfaces of the sample pieces including the printed portion are aligned with the central portion cut into 5 cm × 5 cm, and left to stand under environmental conditions of 40 ° C./90% RH under a load of 500 g / m ² for 24 hours. Then, blocking property was evaluated from the degree of blocking when the sample piece was peeled off.
(Evaluation criteria)
5: The application surfaces are not adhered to each other.
4: The coated surfaces are adhered to each other in a state excluding the load, but the sample piece peels off almost without resistance.
3: Although there is a light resistance, it peels off without causing paper peeling on the coated surface of the sample piece.
2: There is resistance, and peeling of the coated surface of the sample piece occurs.
1: It is difficult for a sample piece to stick completely and to peel off.

(5) Paper surface dryness The dryness was evaluated from the time until the paper surface after the application of the friction resistance-imparting agent was touched with a finger and no moisture was felt.
(Evaluation criteria)
5: Moisture is hardly felt immediately after application.
4: Moisture is not felt after 5 seconds.
3: Moisture is not felt after 10 seconds.
2: Wetness is not felt after 15 seconds.
1: Wetness is felt even after 20 seconds.

From Table 1, in the Example using emulsion resin whose Tg is -50-50 degreeC, the balance of each performance was favorable and the printed matter which had the outstanding performance was obtained. On the other hand, when Tg was outside the above range, the friction resistance, water friction resistance, and blocking properties were inferior (Comparative Examples 2 and 3). In other comparative examples, the performance balance was inferior.

According to the production method of the present invention, it is possible to produce various corrugated cardboard printed products having excellent performance such as friction resistance.

Claims (4)

A rub resistance imparting agent containing 10-50% by mass of an emulsion resin having a glass transition temperature of −50 to 50 ° C. as a solid content on a printing surface immediately after printing ink on a corrugated board printing substrate is applied to a spray system. And a step of coating the emulsion resin so as to have a coating amount of 0.1 to 20 g / m ^{2 in} terms of solid content. The method for producing a corrugated board printed matter according to claim 1, wherein the ink is printed by an ink jet printing method. Furthermore, the manufacturing method of the corrugated board printed matter of Claim 1 or 2 which prints the ink containing a pigment. A corrugated cardboard printed matter obtained from the method for producing a corrugated cardboard printed matter according to claim 1, 2, or 3.