JP6232973B2 - Gravure ink composition for paper and printed matter using the same - Google Patents

Description

  The present invention relates to a gravure ink composition for paper and a printed material using the same. More specifically, a solvent-type gravure ink composition having good blackness and good adhesion and good printability at the time of printing on non-coated paper that easily penetrates ink, and the use thereof It relates to printed matter.

  Gravure printing is used for printing for publishing and packaging applications such as food packaging. One of the major features of gravure printing is that printing on various substrates is possible. For example, printing can be performed on a polyolefin film such as polypropylene, a plastic film substrate such as polyethylene terephthalate, a paper substrate, a metal foil such as an aluminum foil, and the printed matter is used after being subjected to post-processing depending on the application.

  Among them, art paper, coated paper, non-coated paper, etc. are used for the paper base material depending on the viewpoint of design and post-processing. In particular, uncoated paper is inexpensive because it does not require coating of a coating layer, and is widely used for publishing and packaging applications.

  Gravure printing inks are broadly classified into solvent-type gravure printing inks and aqueous gravure printing inks. Compared with water-based gravure printing inks, solvent-type gravure printing inks can be used by dissolving various resins by appropriately using organic solvents such as hydrocarbons, ketones, esters and alcohols. Therefore, by selecting an appropriate resin, there is an advantage that suitability for post-processing such as friction resistance and heat resistance and printability can be obtained.

  However, when the solvent-type gravure printing ink is used for non-coated paper, a significant decrease in density occurs due to high permeability to the substrate. The reason for this is that gravure printing has a low ink viscosity during printing, and the organic solvent has a low surface tension, so that it can easily penetrate into non-coated paper. Therefore, there is a method of increasing the pigment content in the ink in order to maintain a sufficient density even when printed on non-coated paper. However, when the pigment content in the ink is increased, the relative resin content decreases. This resin content lowers the resin content that wraps the pigment dispersed in the ink, resulting in a decrease in printability such as plate fogging, and when printing on non-coated paper, the resin is also transferred to the substrate. Since the resin penetrates, the resin enclosing the pigment is further lowered, and the problem that the adhesion to the base material is lowered due to the occurrence of choking.

  Due to the above problems, when creating printed matter with high penetrability on non-coated paper, use water-based ink such as water-based gravure printing ink with high surface tension, or print with high viscosity. However, when printing on non-coated paper using solvent-based gravure printing ink, it is generally used only for applications where there is no problem at low concentration. there were.

  In particular, compared with other colors, black ink has a noticeable decrease in visual density and blackness due to penetration, and even in offset printing ink, there are various types of pigment carbon black selection and ink manufacturing methods to prevent reduction in density due to penetration. The technique is reported in, for example, Patent Document 1. However, these patents are limited to offset printing inks, and even if they are used in solvent-type gravure printing inks having high penetrability to the substrate, printed matter with a black feeling cannot be obtained. Although the prevention of penetration of solvent-type gravure printing black ink is described in Patent Document 2, the disclosed content is a description of offset printing ink, and even if this is used for solvent-type gravure printing black ink, blackness is felt. Some prints cannot be obtained.

  Carbon black used as a pigment in gravure printing inks is a mixture of spherical carbon particles called primary (basic) particles, forming complex aggregates that are branched in chains like a bunch of grapes. Yes. This aggregate is called an aggregate, and the degree of fusion of the primary particles forming this aggregate is called a structure. In general, it is not patentable that carbon black with a large aggregate diameter, that is, a carbon with a large primary particle size or a high structure, should be selected in order to prevent penetration and maintain printing density on uncoated paper. It is known from Document 1, etc.

The degree of structure can be evaluated by a dibutyl phthalate (abbreviated as DBP in the present invention) oil absorption measurement method. When the structure is high, the DBP oil absorption amount increases. When printing is performed with a solvent-type gravure printing black ink using carbon black having a large DBP oil absorption, it is possible to maintain the printing density by suppressing ink penetration. However, carbon black having a large DBP oil absorption generally has low coloring power, and a large amount of pigment in the ink is required to obtain a good black feeling. In solvent-type gravure printing black ink, if the pigment content in the ink is excessive, it causes deterioration of printing suitability such as plate fog and adhesion failure due to choking phenomenon.

On the other hand, when printing is performed with solvent-type gravure printing black ink using carbon black having a small DBP oil absorption amount, although the coloring power is improved, the printing density is maintained because the ink penetration cannot be suppressed as described above. It is not possible to obtain a good black feeling.

JP 2011-225747 A JP 2004-269572 A

"Carbon Black Handbook" April 15, 1995, 3rd edition, Editorial Issuer Carbon Black Association

  An object of the present invention is to provide a gravure ink composition for paper and printed matter having good blackness when printed on a substrate having high permeability such as non-coated paper, and having good adhesion to the substrate and printability. It is to provide.

As a result of intensive studies to solve the above-mentioned problems, it is possible to combine the above-described high oil absorption carbon black (1) and low oil absorption carbon black (2) having a specific DBP oil absorption amount with a gravure printing ink ink composition for paper. The problem has been solved.
That is, the present invention is a gravure ink composition for paper containing a high oil absorption carbon black (1), a low oil absorption carbon black (2), a resin and a solvent, wherein the resin is nitrified cotton, The DBP oil absorption amount of (1) is A (1), the DBP oil absorption amount of carbon black (2) is A (2), the weight ratio of carbon black (1) in the black ink composition is W (1)%, carbon When the weight ratio of black (2) is W (2)%, the present invention relates to a gravure black ink composition for paper, which is the following (A) to (C).
(A) A (1) is 100 to 140 ml / 100 g, and A (2) is 50 to 70 m.
1/100 g.
(A) (A (1) × W (1) + A (2) × W (2)) / ((W (1) + W (2))
Is 85-100.
(C) W (1) + W (2) is 8 to 11.5.
Furthermore, the present invention contains one or more inorganic fillers selected from silicon dioxide, magnesium carbonate, calcium carbonate and barium sulfate, and the inorganic filler is added in an amount of 0.5 to 3.0 weight in the total amount of the black ink composition. It is related with the gravure ink composition for paper characterized by containing%.
Furthermore, this invention relates to the said gravure black ink composition for papers for printing on uncoated paper .
Furthermore, this invention relates to the printed matter formed by printing the said gravure ink composition for papers on a paper base material.

  The present invention uses a high oil absorption carbon black (1) having a specific DBP oil absorption and a low oil absorption carbon black (2) in combination with a gravure printing ink ink composition for paper to provide a highly permeable base such as non-coated paper. When printed on the material, a gravure black ink composition for paper having good blackness and having good adhesion to the substrate and printability could be obtained.

The high oil absorption carbon black (1) used in the gravure black ink composition for paper of the present invention needs to have a DBP oil absorption of 100 to 140 ml / 100 g. When the DBP oil absorption is smaller than 100 ml / 100 g, the penetration into the base paper cannot be suppressed, and the black feeling is lowered. When the DBP oil absorption is larger than 140 ml / 100 g, the pigment excessively adsorbs the resin component, and the resin component that wraps the dispersed pigment occurs, resulting in a choking phenomenon and reduced adhesion.

The low oil absorption carbon black (2) used in the gravure black ink composition for paper of the present invention needs to have a DBP oil absorption of 50 to 70 ml / 100 g. If the DBP oil absorption is less than 50 ml / 100 g, the printability such as the plate fogging property is lowered. This is because carbon black having a small DBP oil absorption generally exhibits difficulty dispersion. When the DBP oil absorption is greater than 70 ml / 100 g, the black feeling imparted by the low oil absorption carbon black (2) is not sufficient, and the black feeling of the printed matter is lowered.

Regarding the oil absorption of the high oil absorption carbon black (1) and the low oil absorption carbon black (2) used in the gravure black ink composition for paper of the present invention, (A (1) × W (1) + A (2) × W (2)) / ((W (1) + W (2)) is required to be 85 to 100. This equation represents the average oil absorption based on the weight ratio of the two types of carbon black. When the value is 85 or less, the oil absorption amount is small, so that the penetration into the base paper cannot be suppressed, and the black feeling is lowered. When the value is 100 or more, the resin content wrapping the dispersed pigment occurs, A choking phenomenon occurs and adhesiveness decreases.

Further, the amount of use of the high oil absorption carbon black (1) and the low oil absorption carbon black (2) needs to be 8 to 11.5 in W (1) + W (2). If it is 8 or less, the pigment content in the ink coating is reduced and the blackness of the printed matter is not sufficient. If it is more than 11.5, since the pigment content in the ink is excessive, the printability is deteriorated, for example, plate fogging occurs during printing.
In the present invention, W (1) and W (2) are values at the time of ink printing.

The high oil absorption carbon black (1) and the low oil absorption carbon black (2) used in the present invention are called furnace black, and are produced by incomplete combustion of raw materials such as aromatic hydrocarbons in a high-temperature gas in a furnace. Carbon black is used. Furnace black is roughly divided into carbon black for rubber and carbon black for color. Although carbon black for rubber can be used for gravure printing ink, carbon black for color is usually used for gravure printing black ink from the viewpoint of printability such as plate fog. Similarly, it is desirable to use carbon black for color in the high oil absorption carbon black (1) and the low oil absorption carbon black (2) used in the present invention. Some carbon blacks for color are subjected to surface treatment such as surface oxidation for the purpose of improving blackness and ink fluidity. The high oil absorption carbon black (1) and the low oil absorption used in the present invention. As the carbon black (2), it is possible to use carbon black for color which has been subjected to these surface treatments.
The DBP oil absorption in the present invention was measured in accordance with ASTM D-2414.

Furthermore, in the gravure ink composition for paper of the present invention, one or more inorganic fillers selected from silicon dioxide, magnesium carbonate, calcium carbonate, and barium sulfate can be used for the purpose of further preventing penetration. These inorganic fillers are preferably added in an amount of 0.5% to 3% with respect to the gravure ink for paper from the viewpoints of the permeation preventing effect and the printability. Commercially available products can be used for these inorganic fillers, for example, silicon dioxide (Silicia 350 manufactured by Fuji Silysia Co., Ltd.), magnesium carbonate (magnesium carbonate Venus manufactured by Kamijima Chemical Co., Ltd.), calcium carbonate (Shiraka Hana T-DD Shiraishi Calcium And barium sulfate (precipitated barium sulfate BM-110, manufactured by Sakai Chemical Industry Co., Ltd.). Preferred are magnesium carbonate and calcium carbonate.

The resin used for the gravure ink composition for paper of the present invention is at least one of nitrified cotton, chlorinated polyolefin resin, vinyl chloride-vinyl acetate copolymer resin, and lime rosin resin, and is suitable for printing and post-processing. It is possible to select appropriately according to the situation. Commercially available products of these resins can also be used. For example, nitrified cotton (manufactured by KCNC1 / 16G KOREA CNC), chlorinated polyolefin resin (Supercron HP620, manufactured by Nippon Paper Chemicals Co., Ltd.), vinyl chloride-vinyl acetate There are polymerized resin (Solvine A Nissin Chemical Co., Ltd.), lime rosin resin (Arakawa Chemical Co., Ltd.), etc. Moreover, it is also possible to use these resins in combination with a polyurethane resin or an acrylic resin. Preferred are nitrified cotton and chlorinated polyolefin.

The solvent used for the gravure ink composition for paper of the present invention should be appropriately selected from hydrocarbons, ketones, esters, glycol ethers, alcohols, etc. in consideration of the solubility and drying properties of the resin. Is possible. Specifically, hydrocarbons such as toluene and methylcyclohexane, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and n-propyl acetate, glycol ethers such as propylene glycol monomethyl ether and ethylene glycol monopropylene glycol Further, alcohol organic solvents such as methanol, ethanol and propanol can be used alone or in admixture of two or more.

In the gravure ink composition for paper of the present invention, additives such as a pigment dispersant, a leveling agent, an antifoaming agent, a wax, a plasticizer, and a crosslinking agent can be used as necessary.

  The gravure black ink composition for paper of the present invention is supplied to each printing unit alone or mixed by a gravure printing method on a paper substrate such as coated paper and polyethylene laminated paper in addition to highly permeable uncoated paper. Can be printed.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, all “parts” mean “parts by weight”.

<Preparation of resin varnish r (a)>
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 40 parts (including 10 parts isopropyl alcohol) of nitrated cotton “KCNC1 / 16G” manufactured by KOREA CNC, and 60 parts of ethyl acetate in nitrogen While stirring under an air stream, the mixture was dissolved at 40 ° C. for 2 hours to obtain a resin varnish r (a) having a solid content of 30%.

<Preparation of resin varnish r (b)>
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 30 parts of Nippon Paper Chemicals Co., Ltd.'s chlorinated polyolefin resin "Supercron HP620" and 70 parts of toluene are stirred under a nitrogen stream. While being dissolved at 60 ° C. for 2 hours, a resin varnish r (b) having a solid content of 30% was obtained.

<Preparation of resin varnish r (c)>
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 30 parts of vinyl chloride-vinyl acetate copolymer resin “Solvine A” manufactured by Nissin Chemical Co., Ltd. and 70 parts of methyl ethyl ketone are streamed with nitrogen. The mixture was dissolved under stirring at 60 ° C. for 2 hours to obtain a resin varnish r (d) having a solid content of 30%.

<Preparation of resin varnish r (d)>
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 30 parts of lime rosin resin manufactured by Arakawa Chemical Co., Ltd. and 70 parts of toluene were dissolved at 60 ° C. for 2 hours while stirring under a nitrogen stream. Thus, a resin varnish r (d) having a solid content of 30% was obtained.
Table 1 shows the resin varnish.

<Selection of carbon black>
In this example, the following carbon black was used to prepare a gravure black ink composition for paper.
cb (a): “Raven 1040 powder” manufactured by Colombian Carbon (DBP oil absorption 100 ml / 100 g)
cb (b): “Seast SVH” manufactured by Tokai Carbon Co., Ltd. (DBP oil absorption 140 ml / 100 g)
cb (c): “Mitsubishi Carbon # 30” manufactured by Mitsubishi Chemical Corporation (DBP oil absorption 113 ml / 100 g)
cb (d): “Raven 1060 Ultra Powder” manufactured by Colombian Carbon (DBP oil absorption 50 ml / 100 g)
cb (e): “Raven 2000 Powder” (Columbian Carbon Absorption 70 ml / 100 g) manufactured by Colombian Carbon
cb (f): “Raven 1080 Ultra Powder” manufactured by Colombian Carbon Co., Ltd. (DBP oil absorption 60 ml / 100 g)
cb (g): “Raven 510 Ultra Powder” manufactured by Colombian Carbon Co., Ltd. (DBP oil absorption 90 ml / 100 g)
cb (h): “Seast 116HM” manufactured by Tokai Carbon Co., Ltd. (DBP oil absorption 158 ml / 100 g)
cb (i): “Printex 35 powder” manufactured by Degussa (DBP oil absorption 42 ml / 100 g)
cb (j): “Seast 300” manufactured by Tokai Carbon Co., Ltd. (DBP oil absorption 75 ml / 100 g)

In this specification, Examples 14 to 16 are reference examples.
[Example 1]
<Preparation of gravure ink composition 1 for paper>
Resin varnish r (a): 30 parts, high oil absorption carbon black cb (a): 5 parts, low oil absorption carbon black cb (e): 5 parts, ethyl acetate: 10 parts as a solvent, and kneaded in a sand mill A mill base was created. To this, Zaan Cup No. 3 and adjusting the ratio of the resin varnish r (a) and the solvent so that it would be 15 seconds, adding 12 parts of the resin varnish r (a) and 38 parts of ethyl acetate to prepare a gravure ink composition 1 for paper and printing. used.
<How to create printed matter>
The obtained printing ink composition 1 is printed on non-coated paper (XJ amount 64 g / m 2, manufactured by Kishu Paper Co., Ltd.) with a conventional 30μ solid plate using a baby printer of Iwase Printing Machinery Co., Ltd. It was.

[Examples 2 to 16, Comparative Examples 1 to 10]
Examples 2 to 16 and Comparative Examples 1 to 10 produced paper gravure ink compositions 2 to 26 in the same manner as in Example 1 at the mixing ratios shown in Tables 1 and 2, respectively. In Examples 9 to 13, the inorganic filler f (a): silicon dioxide (Silicia 350 manufactured by Fuji Silysia Ltd.), f (b): Magnesium carbonate (magnesium carbonate Venus manufactured by Kanjima Chemical Industries, Ltd.) f (c): Calcium carbonate (Shiraka Hana T-DD, manufactured by Shiroishi Calcium Co., Ltd.), f (d): barium sulfate (precipitated barium sulfate BM-110, manufactured by Sakai Chemical Industry Co., Ltd.) was mixed during mill base preparation and kneaded in a sand mill.

About the printed matter obtained in Examples 1-16 and Comparative Examples 1-10, black feeling and non-coat paper adhesiveness are evaluated, and the black ink composition obtained in Examples 1-16 and Comparative Examples 1-10 is evaluated for printability. Went. The evaluation method and evaluation criteria are shown below. The results are shown in Tables 2 and 3.

<Black feeling>
The density of the printed material was evaluated with an X-RITE densitometer. The practical level is Δ or more.
A: The black density is 1.3 or more.
◯: Black density is 1.2 or more and less than 1.3 Δ: Black density is 1.1 or more and less than 1.2
X: The black density is less than 1.1.

<Non-coated paper adhesion>
A cellophane tape made by Nichiban Co., Ltd., having a width of 1.2 cm was applied to the printed material, and peeled to observe the interface during peeling. The practical level is Δ or more.
○: The base paper peels off.
(Triangle | delta): The part from which a base paper peels, and the part from which an ink coating film is removed generate | occur | produce simultaneously.
X: An ink coating film is taken.

<Printability>
NBR (nitrile butadiene rubber) impression cylinder with hardness of 80Hs, blade thickness of 60μm (base material thickness of 40μm, one side ceramic layer thickness of 10μm), electronic engraving plate made by Toyo Prepress Co., Ltd. (stylus) After setting the printing ink composition on a gravure printing machine manufactured by Fuji Machine Industry Co., Ltd. and rotating the plate at a doctor pressure of 2 kg / cm ² and a rotation speed of 100 m / min for 30 minutes, Printed on the corona-treated surface of a single-sided corona-treated OPP film “Pyrene P2161 (manufactured by Toyobo Co., Ltd.)” at a printing speed of 100 m / min with a printing pressure of 2 kg / cm ² and dried with hot air at 60 ° C. The amount of ink adhering to the (non-image area) was visually evaluated according to the following criteria. The practical level is Δ or more.
○: No ink transfer was observed in the non-image area.
Δ: Ink transfer was observed in a small area of the non-image area.
X: Ink transfer was observed over the entire non-image area.

The printing ink compositions prepared in Examples 1 to 16 were able to obtain good blackness, non-coated paper adhesion, and printability. On the other hand, in Comparative Examples 1, 2, 3, 5, 7, and 10, it was not possible to obtain a printed matter having a good black feeling. In Comparative Examples 4 and 8, the non-coated paper adhesion of the printed matter was poor, and in Comparative Examples 6 and 9, the printability was poor.

Claims (4)

A gravure ink ink composition for paper containing a high oil absorption carbon black (1), a low oil absorption carbon black (2), a resin and a solvent, wherein the resin is nitrified cotton,
The DBP oil absorption of carbon black (1) is A (1), the DBP oil absorption of carbon black (2) is A (2), and the weight ratio of carbon black (1) in the black ink composition is W (1)%. When the weight ratio of carbon black (2) is W (2)%, the following gravure black ink composition for paper is characterized by the following (a) to (c).
(A) A (1) is 100 to 140 ml / 100 g, and A (2) is 50 to 70 m.
1/100 g.
(A) (A (1) × W (1) + A (2) × W (2)) / ((W (1) + W (2))
Is 85-100.
(C) W (1) + W (2) is 8 to 11.5. Furthermore, it contains one or more inorganic fillers selected from silicon dioxide, magnesium carbonate, calcium carbonate and barium sulfate, and contains 0.5 to 3.0% by weight of the inorganic filler in the total amount of the black ink composition. The gravure ink ink composition for paper according to claim 1. The gravure black ink composition for paper according to claim 1 or 2, which is used for printing on uncoated paper. The printed matter formed by printing the gravure ink composition for papers in any one of Claims 1-3 on a paper base material.