JP2001240787A - Ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a publication gravure ink composition which has printability equal to that of an aromatic hydrocarbon based solvent such as toluene as the solvent in the publication gravure ink and excels in drying characteristics, reduction in the odor, and printing effect and uses a solvent which copes with the environment. SOLUTION: The ink composition comprises 30-90 pts.wt. nonaromatic hydrocarbon based solvent based on 100 pts.wt. ink film-constituting material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gravure ink composition used for printing of publications such as newspapers and books, posters, and commercial prints such as calendars.

[0002]

2. Description of the Related Art In general, gravure inks used for publication gravure printing are mainly composed of a rosin-based resin such as a rosin-modified maleic resin or a petroleum resin as a vehicle.
As the solvent, aromatic hydrocarbon-based toluene, xylene and the like are mainly used. These aromatic hydrocarbon solvents,
It is excellent in dissolving power for the resin used in the vehicle, adjustment of ink drying speed, adjustment of ink viscosity, dispersibility of additives, and the like, and is preferably used.

[0003] However, in conventional gravure inks, aromatic hydrocarbon solvents such as toluene are preferably used as solvents because of their solvent characteristics. According to the PRTR Law (Law Concerning Emissions of Specific Chemical Substances into the Environment and Promotion of Improvement of Management) under the Ministry of International Trade and Industry's PRTR Law, as substances suspected to have an adverse effect on the human body, There are environmental issues such as the working environment and the natural environment in emissions.

[0004] The above-mentioned aromatic hydrocarbon solvents have a strong odor of volatile vapor, and also have environmental problems such as air pollution in the air and safety problems of the working environment. A large-scale solvent recovery device (activated carbon adsorption, steam desorption type) is used to recover the solvent. To this end, aqueous inks that do not use solvents such as aromatic hydrocarbon solvents have been proposed so far, but the aqueous inks are slow to dry and cannot be applied to rotary high-speed gravure printing. In addition, the water-based ink has problems in terms of quality, such as paper wrinkles, gloss of printed matter, sticking of ink, printing effects such as tone reproducibility, and price, and economics, and also from the viewpoint of environmental problems. There is a problem that the entire printing system, such as the installation of a large-scale wastewater treatment facility and the ink, paper, printing machine, and dryer, must be considered.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a printing gravure ink having a printability comparable to that of an aromatic hydrocarbon solvent such as toluene as a solvent in gravure ink, and has excellent drying properties, low odor and printing effect. An object of the present invention is to provide a gravure ink composition for publication using an environment-friendly solvent.

[0006]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, preferably, the aniline point is 30 to 80 ° C., the evaporation rate is 150 to 500, and the aromatic content is 0.5. The ink composition using a non-aromatic hydrocarbon solvent of not more than 10% by weight has printability comparable to that of a published gravure ink using an aromatic hydrocarbon solvent such as toluene, and has good drying properties and low odor. It has been found that this is an aroma-free ink composition for gravure publication that has excellent printing effects and does not indicate the harmful effects of aromatic hydrocarbon solvents such as toluene. That is, the present invention provides an ink composition comprising 30 to 90 parts by weight of a non-aromatic hydrocarbon solvent with respect to 100 parts by weight of a constituent material of an ink film.

[0007]

Next, the present invention will be described in more detail with reference to preferred embodiments. As the non-aromatic hydrocarbon solvent mainly characterizing the present invention, a non-aromatic hydrocarbon solvent having an aniline point of 30 to 85 ° C, an evaporation rate of 150 to 500, and an aromatic content of 0.5% or less is used. Is preferred. Aromatic components have an adverse effect on the human body and environmental problems, and these problems are significant in aromatic hydrocarbon solvents such as benzene, toluene, and xylene. For that purpose, the Ministry of Labor's Regulation on Prevention of Obstacles for Specific Chemical Substances, etc.
According to the regulations for prevention of organic solvent poisoning by the Ministry of Labor, the use of those with a total amount of toluene and xylene exceeding 5% by volume is restricted or the presence of the compound is required to be indicated. As a countermeasure for these, for example, positive pentane, isopentane, positive hexane, 2-methylpentane, positive heptane, positive octane, isooctane, trimethylpentane, diisoamyl, dodecane, positive tetradecane However, there is a problem in use because the solubility of the resin component constituting the ink film is poor and the low-temperature fluidity is poor. Further, for example, there are also naphthene-based solvents such as cyclohexylmethane, octadecylcyclohexane, and methylisopropylcyclohexane, but there is a problem in solubility of a resin component which is a constituent material of an ink film.
The storage stability of the ink is not good.

The non-aromatic hydrocarbon solvent of the present invention has an evaporation rate of 150 to 500, preferably 190.
~ 350. If it is less than 150, there is a problem that the drying property at the time of high-speed rotary printing is poor. If the evaporation rate exceeds 500, the drying is too fast, and the transferability of the ink becomes poor due to the development of plate drying and the like. The phenomenon of dropout of the light portion occurs, and tone reproducibility deteriorates. The aniline point is 30 ° C
To 80 ° C, preferably 35 ° C to 50 ° C. Non-aromatic hydrocarbon solvents having an aniline point higher than 80 ° C have a problem that the solubility of the resin component constituting the ink film is reduced. If the solvent temperature is lower than 30 ° C, the solubility is improved, but the solvent releasability is poor. However, there is a problem that the aromatic content increases. The aromatic content is 0.5% by weight or less, and if it exceeds 0.5% by weight, it causes environmental problems such as air pollution.

Particularly preferred non-aromatic hydrocarbon solvents are, for example, non-aromatic hydrocarbon solvents such as methylcyclohexane, ethylcyclopentane and methylcyclopentane which satisfy the above-mentioned conditions, and a mixture thereof or a mixture thereof. And non-aromatic hydrocarbon solvents which are mixtures with other aliphatic hydrocarbon solvents and satisfy the above conditions.

The aniline point is determined according to JIS-K-225.
6 (petroleum product-aniline point and mixed aniline point test method), and the evaporation rate is a comparative evaporation rate obtained by comparing the following formula with butyl acetate as 100 at 25 ° C. Comparative evaporation rate = Evaporation time of butyl acetate × 100 / Evaporation time of required solvent The aromatic content is a value measured according to JIS-K-2536.

The constituent material of the ink film constituting the ink composition of the present invention comprises a resin, a colorant and an additive. The ink film constituent material may not contain a coloring agent, and if not, it can be used as an overcoating agent such as OP varnish. Preferably, the resin is compatible with the non-aromatic hydrocarbon solvent. Further, those having good solvent releasability in drying, gloss, pigment dispersibility, and abrasion resistance and bending property in the bookbinding step from high-speed printing suitability are preferable, and those containing no aromatic hydrocarbon-based compound are preferable.

As the resin component of the above ink film constituting material, for example, magnesium, calcium and zinc are used to increase the softening point based on gum rosin or tall oil rosin, to lower the acid value and to improve solvent releasability. Rosin such as lime drosin which is a resin salt of rosin to which metal salt is added, rosin modified resin such as maleated rosin to which maleic acid is added, rosin modified phenol resin, rosin, rosin polymer, rosin ester, hydrogenated rosin Derivatives and petroleum resins such as aliphatic petroleum resins, and mixtures thereof. As the modified rosin resin, which is a resin salt of such rosin, generally used is a polymerized by a method such as a solution method. In general, in the solution method, a modified rosin resin which is a resin salt of rosin is manufactured for an ink varnish using toluene as a solvent, but in the present invention,
An ink varnish of a modified rosin, which is a resin salt of rosin produced using methylcyclohexane, preferably a non-aromatic solvent described above instead of toluene, and a solid content of 50% by weight is preferred. Further, a solid resin obtained by removing the solvent of the modified rosin resin varnish produced by these solution methods can also be used by dissolving it in the above-mentioned non-aromatic solvent.

Coloring agents are commonly used in gravure inks, for example, carmine 6B, lake C, permanent red 2B, disazo yellow, pyrazolone orange, chromophthal yellow, phthalocyanine blue, phthalocyanine green, quinacridone magenta,
Organic pigments such as Industron Blue, Aniline Black, and Pyrimidine Yellow, for example, zinc white, ultramarine, navy blue, carbon black, chrome vermillion, graphite,
Examples include inorganic pigments such as cadmium yellow, red iron oxide, yellow iron oxide, zinc oxide, titanium oxide, and aluminum powder. Additives may be added in a range that does not interfere with the object of the present invention. Examples of these additives include antifoaming agents such as silicones, surfactants such as anionic surfactants, and waxes such as paraffin wax. And inorganic substances such as calcium carbonate, barium sulfate, magnesium carbonate, clay, talc, silica, and alumina. The ink composition of the present invention is obtained by kneading and homogenizing the above components, and is provided as an organic solvent solution.

The non-aromatic hydrocarbon solvent is used in an amount of 30 to 90 parts by weight, preferably 50 to 80 parts by weight, based on 100 parts by weight of the ink coating material. 9
If the amount exceeds 0 parts by weight, there is a problem that the viscosity of the ink is reduced and the glossiness and tone reproducibility of the printed matter are deteriorated. If the amount is less than 30 parts by weight, the ink is thickened or the solubility of the resin is poor. There is a problem.

[0015]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the description, "part" is based on weight. <Example 1> The following components were thoroughly stirred to prepare an ink composition of the present invention. Limedrodine (50% by weight solution of methylcyclohexane) 57.0 parts Methylcyclohexane * 15.2 parts Disazo Yellow 8.0 parts Calcium carbonate 21.2 parts Polyethylene wax 1.0 part (* aniline point of methylcyclohexane 39.6 ° C, Evaporation rate 320)

Example 2 The following components were thoroughly stirred to prepare an ink composition of the present invention. Limedrozin (50% by weight solution of methylcyclohexane) 57.0 parts Methylcyclohexane 15.2 parts Carmine 6B 6.8 parts Calcium carbonate 20.0 parts Polyethylene wax 1.0 part

Example 3 The following components were thoroughly stirred to prepare an ink composition of the present invention. Limedrozin (50% by weight methylcyclohexane solution) 66.0 parts Methylcyclohexane 13.5 parts Calcium carbonate 20.0 parts Polyethylene wax 0.5 part

Comparative Example 1 The following components were thoroughly stirred to prepare an ink composition of Comparative Example. Limedrozin (50% by weight solution in toluene) 57.0 parts Toluene 15.5 parts Disazo Yellow 8.0 parts Calcium carbonate 21.5 parts Polyethylene wax 1.0 part

Comparative Example 2 The following components were thoroughly stirred to prepare an ink composition of Comparative Example. Limedrozin (50% by weight solution in toluene) 57.0 parts Toluene 15.5 parts Carmine 6B 6.5 parts Calcium carbonate 20.0 parts Polyethylene wax 1.0 part

Comparative Example 3 A commercially available acrylic water-based ink was used. <Evaluation> Using each of the ink compositions obtained above,
High-speed printing was performed on the coated paper with a gravure printing machine at 600 to 800 rpm. The dryness, odor, and gloss of each printed matter were evaluated by the following measurement methods.

(Dryability) The dryness of the printed matter immediately after printing was evaluated by the dryness to the touch and the heat seal test (100
In an atmosphere at a temperature of 5 ° C., the printing surfaces were subjected to a load of 3 kg for 5 seconds (blocking property between printed surfaces), and the evaluation was made according to the following criteria. Table 1 shows the evaluation results. Evaluation point ◎: good drying on the printed surface layer and inside the printed surface layer,
No tack phenomenon due to finger touch was observed, and there was no blocking between ink surfaces. Δ: The printed surface layer part is dry, but the inside of the printed surface layer is slightly dried. There is no blockage between the tact and ink surfaces due to finger touch. X: Poor drying of the printing surface layer and the inside of the printing surface layer, tackiness by finger touch was recognized, and there was blocking between ink surfaces.

(Odor) The odor at the time of printing the printed matter was determined by olfaction according to the following criteria. Table 1 shows the evaluation results. Evaluation point ：: No irritating odor was observed, and the odor was low. X: An irritating odor was recognized and the substance was quite odorous.

(Glossiness and Printability) The glossiness and printability of the printed matter were visually judged according to the following criteria.
Table 1 shows the evaluation results. Evaluation point ：: Good gloss and print tone reproducibility. X: Poor gloss reproducibility and print tone.

[0024]

[Table 1]

[0025]

The ink composition of the present invention comprises
An aniline point of 30-80 ° C. and an evaporative drying rate of 150
By using a non-aromatic solvent of from 500 to 500, the ink composition for gravure printing is excellent in low odor and excellent drying properties. Compared with the conventional ink composition using an aromatic solvent, the working environment is good because it does not have a strong odor and does not mainly contain an aromatic component which is considered to have an adverse effect on the environment. High-speed printing is possible because of good drying properties, and running costs are reduced by improving work efficiency, thereby pursuing economic benefits.

Claims (4)

[Claims] 1. An ink composition comprising 30 to 90 parts by weight of a non-aromatic hydrocarbon solvent with respect to 100 parts by weight of a constituent material of an ink film. 2. The ink composition according to claim 1, wherein the non-aromatic hydrocarbon solvent has an aniline point of 30 ° C. to 80 ° C. 3. The ink composition according to claim 1, wherein the non-aromatic hydrocarbon solvent has an evaporation rate of 150 to 500. 4. The ink composition according to claim 1, wherein the non-aromatic hydrocarbon solvent has an aromatic content of 0.5% by weight or less.