JP7043666B1 - Heat resistance improver, water-based overprint varnish, water-based ink composition for printing, and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a heat resistance improver capable of preparing a printing composition useful as an overprint varnish, an ink composition for printing, etc., which can form a print layer having excellent heat resistance, and to improve the heat resistance. A printing composition useful as an overprint varnish, an ink composition, or the like using an agent is provided. SOLUTION: This is a heat resistance improving agent blended in a printing composition in order to improve the heat resistance of a printing layer formed of the printing composition. Contains unbaked shell powder, binder resin, and aqueous medium. Further, it is a printing composition containing this heat resistance improving agent and used as an overprint varnish, an ink composition, or the like. [Selection diagram] None

Description

The present invention relates to a heat resistance improver, a water-based overprint varnish, a water-based ink composition for printing, and a printed matter, which are used to improve the heat resistance of a printing layer formed of a printing composition.

In recent years, in the fields of wrapping paper, wrapping bags, corrugated cardboard and the like, clear printed matter is required in order to give a high-class image to the contents. As the ink for forming the print layer on such a paper base material such as corrugated sheet, for example, a color material such as a pigment and a component such as a binder resin for adhering the print layer to the paper base material are blended in an aqueous medium. Water-based gravure ink, flexo ink, and the like are generally used.

The ink for printing on a paper substrate such as a corrugated sheet contains, for example, a colored pigment such as carbon black or titanium oxide, a water-soluble acrylic resin, and water, and has improved printability and coating property properties. A water-based ink composition has been proposed (Patent Document 1).

Japanese Unexamined Patent Publication No. 2018-158896

The printed matter obtained by applying ink to a paper substrate to form a printed layer may be heat-treated at a predetermined temperature. For example, in the case of a packaging material such as corrugated cardboard or a packaging container, the printed matter is heated when it is corrugated. However, since the general water-based binder resin blended in ink does not have very high heat resistance, there are problems such as peeling of at least a part of the printing layer or sticking to other laminated layers. In some cases. Even when the ink composition proposed in Patent Document 1 is used, the heat resistance of the formed printed layer cannot be said to be sufficient, and there is room for improvement.

The present invention has been made in view of the problems of the prior art, and the subject thereof is an overprint varnish and an ink composition for printing, which can form a print layer having excellent heat resistance. It is an object of the present invention to provide a heat resistance improver capable of preparing a printing composition useful as a product or the like. Further, an object of the present invention is a printing composition useful as an overprint varnish, an ink composition for printing, etc., which can form a printed layer having excellent heat resistance and abrasion resistance, and a printing composition. An object of the present invention is to provide a printed matter obtained by using this printing composition.

That is, according to the present invention, the following heat resistance improver is provided.
[1] A heat resistance improving agent blended in the printing composition for improving the heat resistance of the printing layer formed of the printing composition, which is an unfired shell powder, a binder resin, and an aqueous medium. A heat resistance improver containing.
[2] The heat resistance improver according to the above [1], wherein the content of the powder of the unbaked shell is 40 to 80% by mass based on the total solid content.

Further, according to the present invention, the following printing composition is provided.
[3] A printing composition containing the heat resistance improving agent according to the above [1] or [2] (hereinafter, also referred to as "first printing composition").
[4] A printing composition containing unbaked shell powder, a binder resin, and an aqueous medium (hereinafter, also referred to as "second printing composition").
[5] The content of the powder of the unbaked shell further containing wax is 1 to 70% by mass based on the total solid content, and the above-mentioned [3] or [4] used as an overprint varnish. The printing composition described.
[6] The content of the powder of the unbaked shell further containing a pigment is 1 to 25% by mass based on the total solid content, and the above-mentioned [3] or [4] used as an ink composition. The printing composition described.
[7] The printing composition according to any one of the above [3] to [6], which is used for printing on a paper substrate.

Further, according to the present invention, the following printed matter is provided.
[8] A printed matter comprising a paper substrate and a printed layer provided on the surface of the paper substrate and formed of the printing composition according to any one of [3] to [7].

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a heat resistance improver capable of preparing a printing composition useful as an overprint varnish, an ink composition for printing, etc., which can form a printing layer having excellent heat resistance. To. Further, according to the present invention, a printing composition useful as an overprint varnish, an ink composition for printing, etc., which can form a printed layer having excellent heat resistance and abrasion resistance, and a printing composition thereof. Printed matter obtained using the composition is provided.

<Heat resistance improver>
Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. The present inventors have improved the heat resistance of a print layer formed of a printing composition such as an overprint varnish (hereinafter, also referred to as “OP varnish”) and an ink composition (hereinafter, also simply referred to as “ink”). Various investigations were made on the components for making the ink. As a result, they have found that the heat resistance of the printing layer formed of the water-based printing composition containing the binder resin is improved by blending the powder of the unbaked shell, and have reached the present invention. That is, the heat resistance improving agent of the present invention is a heat resistance improving agent blended in the printing composition in order to improve the heat resistance of the printing layer formed of the printing composition, and is a powder of unbaked shells. Contains a binder resin and an aqueous medium. Hereinafter, the details of the heat resistance improving agent of the present invention will be described.

(Unbaked shell powder)
Unbaked shells are a component that is also used as a biomass material. By using unbaked shell powder, it is possible to obtain a heat resistance improver capable of preparing a printing composition such as OP varnish or ink that can form a printed layer having excellent heat resistance and abrasion resistance. At the same time, the degree of biomass can be increased.

The unbaked shell powder can be obtained by crushing and classifying the unbaked shell. As the unbaked shell, for example, a shell such as a scallop, an oyster, or a surf clam can be used.

The content of the unbaked shell powder in the heat resistance improver is preferably 40 to 80% by mass, preferably 45 to 70% by mass, based on the total solid content (nonvolatile content) in the heat resistance improver. It is more preferably present, and particularly preferably 48 to 65% by mass. If the content of the powder of the unbaked shell is too small, the effect of improving the heat resistance of the printing layer formed by the printing composition obtained by blending this heat resistance improving agent may be slightly insufficient. On the other hand, if the content of the powder of the unbaked shell is too large, the printability of the printing composition obtained by blending this heat resistance improving agent may be slightly lowered.

The average particle size of the unbaked shell powder is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm, and particularly preferably 0.8 to 2 μm. If the average particle size of the unbaked shell powder is too small, it may be a little difficult to handle. On the other hand, if the average particle size of the unbaked shell powder is too large, the printability of the printing composition obtained by blending this heat resistance improving agent may be slightly lowered, and the printed layer formed (image). ) Tends to be rough. As used herein, the "average particle size of unbaked shell powder" means a cumulative 50% particle size (median size (D ₅₀ )) on a volume basis.

(Binder resin)
As the binder resin, the same binder resin as that used for printing compositions such as OP varnish and ink can be used. This binder resin is a component for improving the film-forming ability of the printing composition and enhancing the adhesion between the substrate such as a paper substrate and the printing layer formed by the printing composition.

As the binder resin, any one that can be used for ordinary OP varnish, water-based ink, or the like can be used. Suitable binder resins include, for example, (meth) acrylic resin (polymer or copolymer of (meth) acrylic acid ester), urethane-modified (meth) acrylic resin, silicone-modified (meth) acrylic resin, styrene- (meth). ) Acrylic copolymer resin, styrene-acrylic acid copolymer resin, styrene-maleic acid copolymer resin, ethylene- (meth) acrylic copolymer resin, polyurethane resin, polyester resin, polystyrene resin, rosin-modified maleic acid resin, vinyl chloride- Vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate-vinyl chloride copolymer resin, vinyl acetate- (meth) acrylic acid copolymer resin, ethylene-vinyl chloride copolymer resin, ethylene-vinyl acetate- Examples thereof include (meth) acrylic copolymer resins, polyvinyl acetal resins, polyamide resins, and cellulose-based resins. Among them, (meth) acrylic resin and styrene-acrylic resin are particularly suitable as the binder resin for paper.

Examples of the form of the binder resin include an aqueous solution type, an emulsion type, and a dispersion type. Among these, it is preferable to use an aqueous solution type or emulsion type binder resin from the viewpoint of enhancing the suitability as a printing ink.

The content of the binder resin in the heat resistance improver is preferably 30 to 80% by mass, preferably 40 to 65% by mass, based on the total solid content (nonvolatile content) in the heat resistance improver. More preferred.

(Aqueous medium)
As the aqueous medium, the same aqueous medium used for printing compositions such as OP varnish and ink can be used. As the aqueous medium, water or a mixed solvent of water and a water-soluble organic solvent can be used. Examples of the water-soluble organic solvent include lower alcohols, polyhydric alcohols, alkyl ethers thereof, alkyl esters thereof and the like. Further specific examples of the water-soluble organic solvent include lower alcohols such as methanol, ethanol, normal propanol and isopropanol; polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol and glycerin; and ethylene glycol. Examples thereof include monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoacetate, diethylene glycol monomethyl ether, and dipropylene glycol monomethyl ether.

(Additive)
The heat resistance improving agent may contain various additives other than the above-mentioned components. Additives include, for example, dispersants, surfactants, defoamers, pH regulators, hardeners, crosslinkers, lubricants, waxes, matting agents, antiblocking agents, leveling agents, coupling agents, antioxidants. , UV absorbers, light stabilizers, preservatives, rust inhibitors, fungicides, antisettling agents, plasticizers, flame retardants, color developeres and the like.

The method for preparing the heat resistance improving agent is not particularly limited, and the essential components such as unbaked shell powder, a binder resin, and an aqueous medium are blended, and if necessary, an additive used is blended and mixed. Therefore, a heat resistance improving agent can be obtained.

<Printing composition>
The first printing composition of the present invention is a composition such as OP varnish or ink, which contains the above-mentioned heat resistance improving agent and is suitable for printing on a substrate such as a paper substrate. The second printing composition of the present invention is a composition of OP varnish, ink, etc. suitable for printing on a substrate such as a paper substrate, which contains unbaked shell powder, a binder resin, and an aqueous medium. It is a thing. Hereinafter, the term "printing composition" simply means any of "first printing composition" and "second printing composition".

The first printing composition contains the above-mentioned heat resistance improver. The first printing composition can be obtained, for example, by adding the above-mentioned heat resistance improver to a known water-based OP varnish, water-based ink, or the like and mixing them. Even if the first printing composition further contains a binder component derived from a known water-based OP varnish, a water-based ink, or the like and a water-based medium as components other than the binder resin derived from the heat resistance improver and the water-based medium. good. The second printing composition also contains unbaked shell powder. The second printing composition may be, for example, added and mixed with unbaked shell powder to a known water-based OP varnish or water-based ink containing a binder resin and an aqueous medium, or may be mixed with unfired shell powder or a binder resin. It can be obtained by mixing an aqueous medium, an additive used if necessary, and the like. Since the printing composition contains unbaked shell powder, it is possible to form a printed layer having improved heat resistance and abrasion resistance.

As the unbaked shell powder contained in the second printing composition, the same powder as the above-mentioned unbaked shell powder contained in the heat resistance improving agent can be used. Further, as the binder resin and the aqueous medium contained in the second printing composition, the same binder resin and the aqueous medium contained in the heat resistance improving agent can be used.

The content of the unbaked shell powder in the printed composition is usually 1 to 70% by mass, preferably 1 to 25% by mass, based on the total solid content in the printed composition.

(wax)
The printing composition preferably further contains wax. By further containing wax, the friction resistance of the formed printed layer can be further improved. As the wax, a hydrocarbon wax can be used. Examples of the hydrocarbon wax include polyethylene wax, polypropylene wax, Fishertropus wax, paraffin wax, microcrystalline wax and the like. Further, the degree of needle entry at 25 ° C. measured in accordance with JIS K 2207 of the hydrocarbon wax is preferably in the range of 0.1 to 20, and preferably in the range of 1 to 15. Is even more preferable.

(Pigment)
The printing composition preferably further contains a pigment as a coloring material. Pigments include, for example, titanium oxide, zinc oxide, lead oxide, zinc sulfide, aluminum, mica, titanium oxide-coated mica (pearl pigment), bronze powder, chrome vermillion, yellow lead, cadmium yellow, cadmium red, ultramarine blue, dark blue. , Bengala, yellow iron oxide, iron black, carbon black and other inorganic pigments; barium sulfate, calcium carbonate, magnesium carbonate, aluminum hydroxide, silica, mica, kaolin, and clay and other extender pigments (inorganic pigments); monoazo Pigments, disazo pigments, condensed azo pigments, phthalocyanine pigments, anthracinone pigments, quinacridone pigments, isoindolin pigments, isoindolinone pigments, thioindigo pigments, pyrolopyrrole pigments, azomethine azo pigments, perinone pigments. Pigments, organic pigments such as perylene-based pigments; and the like.

(Overprint varnish)
The printing composition containing wax can be suitably used as an overprint varnish (OP varnish). OP varnish is a composition for forming a film layer (printing layer) for covering an image formed with ink or the like or a printing layer on a base material. The content of the unbaked shell powder in the printing composition used as the OP varnish is preferably 1 to 70% by mass based on the total solid content (nonvolatile content) in the printing composition, and is preferably 5 to 70% by mass. It is more preferably 30% by mass, and particularly preferably 10 to 20% by mass. If the content of the powder of the unbaked shell is too small, the effect of improving the heat resistance of the formed printed layer may be slightly insufficient. On the other hand, if the content of the powder of the unbaked shell is too large, the printability of the printing composition may be slightly lowered.

(Ink composition)
A printing composition containing a pigment can be suitably used as an ink composition (ink). The ink is a composition for forming a printing layer such as an image or a printing layer on a base material. The ink composition may further contain the above-mentioned wax. The content of the unbaked shell powder in the printing composition used as the ink is preferably 1 to 25% by mass based on the total solid content (nonvolatile content) in the printing composition, and is preferably 3 to 20%. It is more preferably mass%, and particularly preferably 5 to 15 mass%. If the content of the powder of the unbaked shell is too small, the effect of improving the heat resistance of the formed printed layer may be slightly insufficient. On the other hand, if the content of the powder of the unbaked shell is too large, the printability of the printing composition may be slightly lowered.

The printing composition is preferably used for gravure printing, flexographic printing, offset printing, screen printing, etc., which are suitable for printing on a base material such as a paper base material. That is, the printing composition is preferably a composition for gravure printing, flexographic printing, offset printing, or screen printing. Further, the printing composition is preferably used for printing on a paper substrate. The surface of the plastic film is smooth. Therefore, when printing on a plastic film with an ink to which powder of unbaked shells is added, unevenness may be easily formed on the formed printed surface, and the gloss may be slightly lowered. This causes a slight white blur in chromatic inks such as indigo inks and black inks, which is a factor that hinders clear printing. On the other hand, since the surface of the paper substrate has irregularities, when printing is performed on the paper substrate with ink to which powder of unfired shells is added, the powder of unfired shells fills the irregularities on the surface of the paper substrate. A uniform printed surface can be formed without causing a feeling of white blur. Therefore, when the printing composition of the present invention is used as an ink composition for printing on a paper substrate, it is suitable not only for white ink but also for chromatic color ink and black ink other than white ink.

<Printed matter>
The printed matter of the present invention includes a paper base material and a printed layer provided on the surface of the paper base material and formed of the above-mentioned printing composition. That is, since the printed matter of the present invention is produced using the above-mentioned printing composition as a constituent material, a printed layer having excellent heat resistance and friction resistance and a high degree of biomass is formed. Further, the printing layer formed by using the printing composition containing a pigment as an ink has a high density.

As the paper base material, various types of paper can be used. Since the print layer formed by using the above-mentioned printing composition has high heat resistance, the corrugated board base paper (medium shin base paper, front liner, and back liner) that may be heat-treated in the manufacturing process thereof, or a combination thereof. Paperboard such as a corrugated cardboard sheet is more preferable.

A printed matter can be obtained by providing a printing layer formed of the printing composition on the surface of the paper substrate. That is, the method for producing a printed matter includes a step (printing step) of printing and applying the above-mentioned printing composition on the surface of a paper substrate to form a printed layer. Since the formed print layer has good heat resistance, it is preferable to further have a step (heat treatment step) of heat-treating the formed print layer to, for example, 160 ° C. or higher.

In the printing step, for example, a printing composition or a printing composition is printed with a diluted ink diluted with water, a solvent, or the like, and then a volatile component (solvent) is dried and removed to form a printing layer. Thereby, a printed matter can be obtained. The thickness of the printed layer is preferably 0.1 to 10 μm, more preferably 0.5 to 7 μm, and particularly preferably 1 to 3 μm.

Printing on a paper substrate can be performed by, for example, gravure printing, flexographic printing, offset printing, screen printing, or the like. Of these, gravure printing and flexographic printing are preferable, and gravure printing is even more preferable. The print layer can be provided on the whole or a part of the paper substrate. For example, the print layer may be provided on one side of the paper substrate, the print layer may be provided on both sides, the print layer may be provided on the entire one side, or the print layer may be provided on a part of one side.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In addition, "part" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

<Preparation of OP varnish (1)>
(Example 1)
Water and a defoaming agent were placed in a stirrer and stirred, and then an acrylic emulsion was added and further stirred to obtain a uniform aqueous varnish for dispersion. Unbaked shell powder was added to the obtained water-based varnish for dispersion, and the mixture was further stirred, and then dispersed using a media bead mill to obtain a high-concentration shell dispersion. Acrylic emulsion, aqueous acrylic solution, wax dispersion, defoaming agent, and water were added to the obtained shell dispersion and stirred to obtain OP varnish. The formulation of the obtained OP varnish is shown in Table 1. The details of each component used are shown below.

-Defoamer: Product name "FS Antifoam 013A", manufactured by Dow Chemical Co., Ltd.-Acrylic emulsion: Aqueous dispersion of styrene-acrylic copolymer, product name "John Krill PDX-7177", manufactured by BASF, solid content 36 %
-Acrylic aqueous solution: Acrylic polymer aqueous solution, trade name "John Krill PDX-6137A", manufactured by BASF, solid content 28%
-Unbaked shell powder: Unbaked scallop shell powder, biomass degree <100%, average particle size 1.55 μm, trade name "scallop powder S" (manufactured by NC Corporation)
-Wax dispersion: Water dispersion of polyolefin wax, trade name "Chemipearl W310", manufactured by Mitsui Chemicals, Inc., solid content 40%

(Examples 2 to 6, Comparative Example 1)
OP varnish was obtained in the same manner as in Example 1 described above, except that the formulation shown in Table 1 was used.

<Evaluation of OP varnish (1)>
(Preparation of test sample (printed matter))
The OP varnish was diluted with a mixed solvent of 40 parts of water and 60 parts of isopropyl alcohol (IPA), and the viscosity was adjusted with Zahn Cup # 3 for 16 seconds to prepare a printing varnish. Using a rotary gravure proofing machine set with a mesh gravure, 175-line, and 35 μm plate, water-based gravure indigo ink was applied to black mount paper, coated cardboard, and single-gloss paper to print the lower layer. Then, using a Helio 175L compressed plate, a printing varnish was overlaid on the printing surface of the lower layer for printing, and then left at room temperature for 1 day to obtain a test sample (printed matter).

(Heat-resistant)
A soft aluminum foil was placed on the printed surface of the prepared test sample so that the glossy surface was in contact with the printed surface. A heat seal bar was placed on the aluminum foil, a load of 2 kgf was applied, and the mixture was heated at 170 ° C., 180 ° C., 190 ° C., 200 ° C., and 210 ° C. for 10 seconds. After the temperature of the test sample returned to room temperature, the aluminum foil was peeled off, and the heat resistance of the printed layer was evaluated according to the evaluation criteria shown below. The results are shown in Tables 2-4.
◯: The print layer was not transferred to the aluminum foil, and there was no peeling resistance.
○ △ ～ △: The print layer was moderately transferred to the aluminum foil, and there was a slight peeling resistance.
Δ× ～ ×: The print layer was completely transferred to the aluminum foil, and there was a large peeling resistance.

(Abrasion resistance)
The surface of the printed layer was rubbed with a cotton cloth 500 g × 100 times using a Gakushin-type abrasion-resistant fastness tester. The state of the cotton cloth after rubbing was confirmed, and the abrasion resistance of the printed layer was evaluated according to the evaluation criteria shown below. The results are shown in Tables 2-4. Among the evaluation results, "○-" means an evaluation between "○" and "○ △".
◯: The print layer was not transferred.
○ △ ～ △: The print layer was moderately transferred.
Δ × ～ ×: The print layer was completely transferred.

<Preparation of ink (1)>
(Example 7)
Water and a defoaming agent were placed in a stirrer and stirred, and then an acrylic emulsion was added and further stirred to obtain a uniform aqueous varnish for dispersion. In the obtained aqueous varnish for dispersion, P.I. Y. 14. Unbaked shell powder, light calcium carbonate, and precipitated barium sulfate were added and further stirred, and then dispersed using a media bead mill to obtain a high-concentration pigment dispersion. An acrylic emulsion, an aqueous acrylic solution, a wax dispersion, an antifoaming agent, and water were added to the obtained pigment dispersion and stirred to obtain yellow ink. Table 5 shows the formulation of the obtained yellow ink. The details of each component used are shown below.

-Defoamer: Product name "FS Antifoam 013A", manufactured by Dow Chemical Co., Ltd.-Acrylic emulsion: Aqueous dispersion of acrylic-styrene copolymer, product name "John Krill PDX-7177", manufactured by BASF, solid content 36 %
-Acrylic aqueous solution: Acrylic polymer aqueous solution, trade name "John Krill PDX-6137A", manufactured by BASF, solid content 28%
-Unbaked shell powder: Unbaked scallop shell powder, biomass degree 100%, average particle size 1.55 μm, trade name "scallop powder S" (manufactured by NC Corporation)
-Wax dispersion: Water dispersion of polyolefin wax, trade name "Chemipearl W310", manufactured by Mitsui Chemicals, Inc., solid content 40%
・ P. Y. 14: Pigment Yellow 14
・ P. B. 15: 4: Pigment Blue 15: 4
・ P. R. 146: Pigment Red 146
・ P. Bk. 7: Pigment Black 7

(Examples 8 to 14, Comparative Examples 2 to 13)
Yellow ink, cyan ink, magenta ink, and black ink were obtained in the same manner as in Example 7 described above, except that the compounding formulations shown in Tables 5 to 8 were used.

<Ink evaluation (1)>
(Preparation of test sample (printed matter))
Each ink was diluted with a mixed solvent of 40 parts of water and 60 parts of isopropyl alcohol (IPA), and the viscosity was adjusted in 16 seconds with Zahn Cup # 3 to prepare a printing ink. Using a rotary gravure proofing machine set with Helio 175L compressed plate, apply printing ink to art paper, coated cardboard, K liner paper, and white liner paper, and then print at room temperature for one day. It was left to stand to obtain a test sample (printed matter).

(concentration)
Using a colorimeter (trade name "eXact", manufactured by X-Rite), the density (D) of the print layer formed on the art paper was measured under the conditions of a light source: D50 and an observation field of view: 2 °. The results are shown in Tables 9-12.

(Metastatic)
Visually check the condition of the surface (printing surface) of the print layer solidly printed on art paper, coated cardboard, K-liner paper, and white liner paper, and transferability (1) (art paper) according to the evaluation criteria shown below. , Coated cardboard), and transferability (2) (K liner paper, white liner paper) were evaluated. The results are shown in Tables 9-12.
◯: The printed surface was uniform.
◯ Δ: The printed surface was almost uniform.
Δ: Some printing unevenness was confirmed.
Δ ×: Printing unevenness and roughness occurred.
X: There was uneven printing on the entire surface.

(Heat-resistant)
A soft aluminum foil was placed on the printed surface of the prepared test sample so that the glossy surface was in contact with the printed surface. A heat seal bar was placed on the aluminum foil, a load of 2 kgf was applied, and the mixture was heated at 170 ° C., 180 ° C., 190 ° C., 200 ° C., and 210 ° C. for 10 seconds. After the temperature of the test sample returned to room temperature, the aluminum foil was peeled off, and the heat resistance of the printed layer was evaluated according to the evaluation criteria shown below. The results are shown in Tables 9-12.
◯: The print layer was not transferred to the aluminum foil, and there was no peeling resistance.
○ △ ～ △: The print layer was moderately transferred to the aluminum foil, and there was a slight peeling resistance.
Δ× ～ ×: The print layer was completely transferred to the aluminum foil, and there was a large peeling resistance.

(Abrasion resistance)
The surface of the printed layer was rubbed with a cotton cloth 500 g × 100 times using a Gakushin-type abrasion-resistant fastness tester. The state of the cotton cloth after rubbing was confirmed, and the abrasion resistance of the printed layer was evaluated according to the evaluation criteria shown below. The results are shown in Tables 9-12.
◯: The print layer was not transferred.
○ △ ～ △: The print layer was moderately transferred.
Δ × ～ ×: The print layer was completely transferred.

<Preparation of OP varnish (2)>
(Example 15)
Water, IPA, and an antifoaming agent were placed in a stirrer and stirred, and then an acrylic emulsion was added and further stirred to obtain a uniform aqueous varnish for dispersion. Unbaked shell powder was added to the obtained water-based varnish for dispersion, and the mixture was further stirred, and then dispersed using a media bead mill to obtain a high-concentration shell dispersion. Acrylic emulsion, urethane emulsion, wax dispersion, defoaming agent, and water were added to the obtained shell dispersion and stirred to obtain OP varnish. The formulation of the obtained OP varnish is shown in Table 13. The details of each component used are shown below.

-Defoamer: Product name "FS Antifoam 013A", manufactured by Dow Chemical Co., Ltd.-Acrylic emulsion: Aqueous dispersion of styrene-acrylic copolymer, product name "John Krill PDX-7177", manufactured by BASF, solid content 36 %
-Urethane emulsion: Polyurethane resin, trade name "UCOAT UWS-145", manufactured by Sanyo Chemical Industries, Ltd., solid content 38%
-Unbaked shell powder: Unbaked scallop shell powder, biomass degree <100%, average particle size 1.55 μm, trade name "scallop powder S" (manufactured by NC Corporation)
-Wax dispersion: Water dispersion of polyolefin wax, trade name "Chemipearl W310", manufactured by Mitsui Chemicals, Inc., solid content 40%

(Examples 16 and 17, Comparative Example 14)
OP varnish was obtained in the same manner as in Example 15 described above, except that the formulation shown in Table 13 was used.

<Evaluation of OP varnish (2)>
(Preparation of test sample (printed matter))
The OP varnish was diluted with water and the viscosity was adjusted with Zahn Cup # 4 for 16 seconds to prepare a printing varnish. Anilox roll 400 LPI was used, a flexo hand proofer was used, and a water-based flexo indigo ink was applied to a single glossy paper (2.0 kg / cm ² ) to print the lower layer. Next, using Anilox Roll 300 LPI, a printing varnish was overlaid on the printing surface of the lower layer for printing, and then left at room temperature for 1 day to obtain a test sample (printed matter).

(Heat-resistant)
A soft aluminum foil was placed on the printed surface of the prepared test sample so that the glossy surface was in contact with the printed surface. A heat seal bar was placed on the aluminum foil, a load of 2 kgf was applied, and the mixture was heated at 80 ° C., 90 ° C., 100 ° C., 110 ° C., and 120 ° C. for 2 seconds and 10 seconds. After the temperature of the test sample returned to room temperature, the aluminum foil was peeled off, and the heat resistance of the printed layer was evaluated according to the evaluation criteria shown below. The results are shown in Tables 14 and 15.
◯: The print layer was not transferred to the aluminum foil, and there was no peeling resistance.
○ △ ～ △: The print layer was moderately transferred to the aluminum foil, and there was a slight peeling resistance.
Δ× ～ ×: The print layer was completely transferred to the aluminum foil, and there was a large peeling resistance.

(Abrasion resistance)
The surface of the printed layer was rubbed with a cotton cloth 500 g × 100 times using a Gakushin-type abrasion-resistant fastness tester. The state of the cotton cloth after rubbing was confirmed, and the abrasion resistance of the printed layer was evaluated according to the evaluation criteria shown below. The results are shown in Tables 14 and 15.
◯: The print layer was not transferred.
○ △ ～ △: The print layer was moderately transferred.
Δ × ～ ×: The print layer was completely transferred.

<Ink preparation (2)>
(Examples 18 and 19, Comparative Example 15)
The water-based flexo indigo ink (trade name "Hydric FCF 739 indigo M-4, manufactured by Dainichiseika Kogyo, urethane-based water-based flexo ink)" and the OP varnish prepared in Example 17 are mixed in the ratio shown in Table 16. And stirring to obtain ink.

<Ink evaluation (2)>
(Preparation of test sample (printed matter))
Each ink was diluted with water, and the viscosity was adjusted with Zahn Cup # 4 for 16 seconds to prepare a printing ink. Anilox roll 400 LPI is used, a flexo hand proofer is used, and printing ink is applied to single gloss paper (2.0 kg / cm ² ) and art paper (2.0 kg / cm ² ), respectively, and then printing is performed at room temperature. A test sample (printed matter) was obtained by leaving it for one day.

(Heat-resistant)
A soft aluminum foil was placed on the printed surface of the prepared test sample so that the glossy surface was in contact with the printed surface. A heat seal bar was placed on the aluminum foil, a load of 2 kgf was applied, and the mixture was heated at 80 ° C., 90 ° C., 100 ° C., 110 ° C., and 120 ° C. for 2 seconds. After the temperature of the test sample returned to room temperature, the aluminum foil was peeled off, and the heat resistance of the printed layer was evaluated according to the evaluation criteria shown below. The results are shown in Tables 17 and 18.
◯: The print layer was not transferred to the aluminum foil, and there was no peeling resistance.
○ △ ～ △: The print layer was moderately transferred to the aluminum foil, and there was a slight peeling resistance.
Δ× ～ ×: The print layer was completely transferred to the aluminum foil, and there was a large peeling resistance.

(Abrasion resistance)
The surface of the printed layer was rubbed with a cotton cloth 500 g × 100 times using a Gakushin-type abrasion-resistant fastness tester. The state of the cotton cloth after rubbing was confirmed, and the abrasion resistance of the printed layer was evaluated according to the evaluation criteria shown below. The results are shown in Tables 17 and 18.
◯: The print layer was not transferred.
○ △ ～ △: The print layer was moderately transferred.
Δ × ～ ×: The print layer was completely transferred.

The heat resistance improver of the present invention is useful as a component for preparing a printing composition useful as an overprint varnish, an ink composition for printing, or the like, which can form a printing layer having excellent heat resistance.

Claims (10)

A heat resistance improver blended in the printing composition in order to improve the heat resistance of the print layer formed of the printing composition.
A heat resistance improver containing unbaked shell powder, a binder resin, and an aqueous medium. The heat resistance improver according to claim 1, wherein the content of the powder of the unbaked shell is 40 to 80% by mass based on the total solid content. Contains unbaked shell powder, binder resin, wax , and aqueous medium ,
The content of the powder of the unbaked shell is 1 to 70% by mass based on the total solid content.
The binder resin is urethane-modified (meth) acrylic resin, silicone-modified (meth) acrylic resin, styrene- (meth) acrylic copolymer resin, styrene-acrylic acid copolymer resin, styrene-maleic acid copolymer resin, ethylene- ( Meta) Acrylic copolymer resin, polyurethane resin, polyester resin, polystyrene resin, rosin-modified maleic acid resin, vinyl chloride-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate-vinyl chloride copolymer resin, Selected from the group consisting of vinyl acetate- (meth) acrylic acid copolymer resin, ethylene-vinyl chloride copolymer resin, ethylene-vinyl acetate- (meth) acrylic copolymer resin, polyvinyl acetal resin, polyamide resin, and cellulose-based resin. Aqueous overprint varnish , which is at least one aqueous or aqueous emulsion type binder resin . The water-based overprint varnish according to claim 3, which is used for printing on a paper substrate. The paper base material is a corrugated board base paper or a paperboard in which the corrugated board base paper is combined.
The water-based overprint varnish according to claim 4, which is used to form a print layer to be heat-treated after printing on the paper substrate. A printed matter comprising a paper substrate and a printed layer provided on the surface of the paper substrate and formed of the water-based overprint varnish according to any one of claims 3 to 5. Contains unbaked shell powder, binder resin, pigments , and aqueous media ,
The content of the powder of the unbaked shell is 1 to 25% by mass based on the total solid content.
The binder resin is urethane-modified (meth) acrylic resin, silicone-modified (meth) acrylic resin, styrene- (meth) acrylic copolymer resin, styrene-acrylic acid copolymer resin, styrene-maleic acid copolymer resin, ethylene- ( Meta) Acrylic copolymer resin, polyurethane resin, polyester resin, polystyrene resin, rosin-modified maleic acid resin, vinyl chloride-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate-vinyl chloride copolymer resin, Selected from the group consisting of vinyl acetate- (meth) acrylic acid copolymer resin, ethylene-vinyl chloride copolymer resin, ethylene-vinyl acetate- (meth) acrylic copolymer resin, polyvinyl acetal resin, polyamide resin, and cellulose-based resin. A water-based printing ink composition (excluding food-grade ink) which is at least one kind of aqueous solution type or water-based emulsion type binder resin . The water-based printing ink composition according to claim 7 , which is used for printing on a paper substrate. The paper base material is a corrugated board base paper or a paperboard in which the corrugated board base paper is combined.
The water-based ink composition for printing according to claim 8, which is used to form a print layer to be heat-treated after printing on the paper substrate. A printed matter comprising a paper substrate and a printed layer provided on the surface of the paper substrate and formed of the water-based printing ink composition according to any one of claims 7 to 9 .