JP2003313482A - Offset printing ink composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an offset printing ink composition excellent in setting properties and gloss. <P>SOLUTION: The offset printing ink composition comprises a pigment (A), and a resin varnish (B) obtained by heating and dissolving a rosin-based resin, a vegetable oil-modified alkyd resin and a vegetable oil component, and can further contain another vegetable oil component (C) other than the components contained in the resin varnish (B). In the case that the ink composition does not contain the component (C), the resin varnish (B) has such properties that it gets cloudy before or at the same time that the amount of n-hexane added to 1 g of the resin varnish (B) adds up to 2 g at a temperature of 25°C. In the case that the ink composition contains the component (C), a mixture (D), which is obtained by mixing the resin varnish (B) with the vegetable oil component (C) at a ratio corresponding to the ratio of the all resin varnishes (B) to the vegetable oil components (C) contained in the offset printing ink composition, has such properties that it gets cloudy before or at the same time that the amount of n-hexane added to 1 g of the mixture (D) adds up to 2 g at a temperature of 25°C. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset printing ink composition, and more particularly to an offset printing ink composition that does not substantially contain a mineral oil component in offset printing.

[0002]

2. Description of the Related Art Conventionally, offset printing inks are composed of pigments, resin varnishes, mineral oils, vegetable oils and the like.
In recent years, with increasing awareness of environmental issues, printing inks are increasingly required to deal with environmental issues year by year, and as part of the countermeasures, some of the volatile mineral oils used as raw materials have been used. Alternatively, all of them are replaced with a non-volatile vegetable oil component such as vegetable oil or a fatty acid ester derived from vegetable oil, so-called non-VOC (Volatil).
e Organic Compound (volatile organic compound) or low VOC ink has been attracting attention.

However, just replacing the vegetable oil component in such a conventional offset printing ink composition results in a longer set time, which may result in backing (primary blocking) when the printed materials are stacked on the sticks immediately after printing and printed materials. Problems such as blocking during processing (secondary blocking) occur. Here, the term "set" refers to a state in which the solvent is removed from the ink film mainly by permeation into the paper surface and the surface tack of the ink disappears. The viscosity of the solvent and the dissolving power of the resin affect the release rate. When a solvent having a high dissolving power of the resin or a solvent having a high viscosity is used, it takes a long time to remove from the ink and the settability is deteriorated. Typically,
Since the vegetable oil component has a higher solubility for dissolving the resin and has a higher viscosity, in the case of the ink in which the solvent component is replaced with the vegetable oil component from the solvent component, the settability is slowed for the reason described above.

Therefore, in order to improve the settability of the ink, it is necessary to quickly remove the solvent from the ink. However, if the settability is improved by such a method, the gloss is usually lowered. Are known. This is because if the solvent is quickly removed from the ink, the viscosity of the ink will increase immediately after printing, and setting / drying will occur before the ink surface becomes smooth. In the lowered ink system, the fluidity of the ink itself is low, and this tendency becomes remarkable. Further, in such a system, the wettability of the resin with respect to the pigment is not sufficient, which is also a factor that a sufficient gloss cannot be obtained. Therefore, it is difficult to achieve compatibility between ink settability and gloss as performances that are not compatible with each other. Even if the solvent is removed from the ink at a high rate to improve the settability, the gloss is reduced and a practical ink composition is obtained. The current situation is that you cannot get things.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention provides an offset printing ink composition which is an ink containing substantially no mineral oil component and which is excellent in both settability and gloss. Is an issue.

[0006]

That is, the present invention is an offset printing ink composition containing substantially no mineral oil component, wherein the offset printing ink composition comprises a pigment (A) and a resin varnish (B). ) As an essential component, the resin varnish (B) is a resin varnish obtained by heating and dissolving a rosin resin, a vegetable oil-modified alkyd resin and a vegetable oil component, and the offset printing ink composition is a vegetable oil. The component (C) may be contained as a vegetable oil component other than the component contained in the resin varnish (B), and when the vegetable oil component (C) is not contained, the resin varnish (B) has a temperature of 25 ° C. When the amount of normal hexane added is 2 g or less with respect to 1 g of the resin varnish (B) under the above temperature, and it contains the vegetable oil component (C), the resin varnish (B) and When the vegetable oil component (C) is mixed in a ratio corresponding to all the resin varnish (B) and the vegetable oil component (C) contained in the offset printing ink composition to form a mixture (D), The mixture (D) is 25
The present invention relates to an offset printing ink composition having a property of adding 2 g or less of normal hexane to 1 g of the mixture (D) at a temperature of ° C and having a turbid appearance. The present invention is an offset printing ink composition containing a pigment (A), a resin varnish (B), and optionally a vegetable oil component (C), and substantially no mineral oil component. The term "does not contain mineral oil" means that, except when mineral oil is used as a solvent for additives, etc., dissolution of resin varnish, viscosity adjustment of ink, etc.
It means that mineral oil is not used for the purpose of its original function as an ink solvent.

The present invention also relates to the offset printing ink composition, wherein the rosin-based resin is a rosin-modified phenolic resin or a rosin-modified maleic resin. Furthermore,
The present invention relates to the offset printing ink composition, wherein the vegetable oil component is a vegetable oil and / or a fatty acid ester derived from a vegetable oil. The present invention is described in detail below.

In the present invention, the vegetable oil component is used in place of the mineral oil component, but since the solubility with the resin improves as it is and the time until setting becomes long, a low solubility type rosin resin is used. By accelerating the release of the vegetable oil component, while solving the problem of setting properties, for the decrease in gloss caused by accelerating the release of the vegetable oil component, a rosin resin and a vegetable oil-modified alkyd resin are used in combination,
Further, they have found that excellent gloss can be obtained by using a resin varnish (B) obtained by heating and dissolving it together in a vegetable oil component, and completed the present invention.

For example, the rosin resin used in the present invention is soluble in vegetable oil components, but insoluble in hydrocarbon solvents such as normal hexane. Therefore, when normal hexane is added to the rosin-based resin-vegetable oil component dissolution system (mixture), the rosin-based resin eventually becomes unable to maintain the dissolved state, and the system precipitates and becomes cloudy, but at this time,
The lower the solubility of the rosin-based resin with respect to the vegetable oil component, the smaller the amount of normal hexane added and the poorer the solvent, the more precipitation occurs.

From such a relationship, the amount of normal hexane added until the resin is precipitated can be used as an index of the solubility of the resin in the vegetable oil component. In the present invention, the offset printing ink composition is a vegetable oil component. (C)
May be contained as a vegetable oil component other than the component contained in the resin varnish (B), so when the vegetable oil component (C) is not contained, the resin varnish (B) is
At a temperature of 25 ° C., 1 g of the resin varnish (B) has a property of becoming cloudy when the addition amount of normal hexane is 2 g or less,
When the vegetable oil component (C) is included, the resin varnish (B) and the vegetable oil component (C) added later are
All resin varnishes (B) contained in the ink composition
And a vegetable oil component (C) at a ratio corresponding to each other to form a mixture, a resin having a property of becoming cloudy at a temperature of 25 ° C. with respect to 1 g of the mixture at a normal hexane addition amount of 2 g or less. It has been found that the use of a vegetable oil component system can improve the settability.

However, as described above, even if the setting property is improved by using such a low-solubility resin, there remains a problem that the gloss of the ink is lowered as it is. Therefore, in the present invention, the use of a rosin-based resin and a vegetable oil-modified alkyd resin in combination, and by heating and dissolving them together in a vegetable oil component and using them as a mixed resin varnish is characterized by preventing gloss reduction. It is a thing.

The mechanism by which the reduction of the gloss of the ink can be prevented by such a method is not clear, but as the factors of the gloss reduction, both the smoothness of the ink film surface and the wettability of the resin with the pigment are defective. Therefore, when using a vegetable oil-modified alkyd resin having a lower solubility and a relatively high solubility rosin-based resin in a uniform mixed state, even if the same solubility as when used separately, It is considered that the smoothness and the wettability with respect to the pigment are improved.

[0013]

The offset printing ink composition of the present invention will be described in more detail below. As the pigment (A) that can be used to obtain the offset printing ink composition of the present invention, a colorless or colored inorganic or organic pigment that is commonly used in offset printing inks can be used.
Specifically, titanium dioxide, barium sulfate, calcium carbonate, inorganic pigments such as magnetic iron oxide, azo pigments, phthalocyanine pigments, isoindoline pigments, anthraquinone pigments,
Organic pigments such as quinacridone pigments; car black and the like can be used. These may be used alone or in combination of two or more. The content of the colorant in the offset printing ink composition is preferably about 3 to 40% by weight.

The rosin-based resin used in the resin varnish (B) used in the offset printing ink composition of the present invention is preferably a rosin-modified phenol resin and / or a rosin-modified maleic acid resin. More than one species can be used.

As the rosin-modified phenol resin,
Examples thereof include those obtained by reacting a rosin or a derivative thereof, a phenol aldehyde addition condensate (so-called resole), and optionally a polyhydric alcohol. Here, the rosins or their derivatives represent rosins or their carboxyl group-containing derivatives. Examples of the rosins include gum rosin, wood rosin, tall oil rosin, disproportionated rosin, hydrogenated rosin and polymers thereof, and the like, as derivatives thereof, unsaturated carboxylic acids such as maleic acid, itaconic acid and crotonic acid. And a carboxyl group-containing derivative such as a rosin derivative to which is added.
As the rosin-modified maleic acid resin, those usually used for offset printing inks can be used.

The vegetable oil-modified alkyd resin used in the resin varnish (B) is usually a polybasic acid such as phthalic anhydride or isophthalic acid, and a polyhydric alcohol such as glycerin, pentaerythritol or trimethylolpropane. The alkyd resin obtained as a reaction component is more easily dissolved in a vegetable oil component, and soybean oil, cottonseed oil, linseed oil, safflower oil, tung oil, tall oil are used for the purpose of improving fluidity due to an intramolecular plasticizing effect. , A dehydrated castor oil, a canola oil or the like modified with a drying oil or a semi-drying oil. Among these, a long oil type alkyd resin modified with soybean oil and having a high modified vegetable oil content is preferably used. These may be used alone or in combination of two or more.

As the vegetable oil component for dissolving these rosin resin and vegetable oil-modified alkyd resin, vegetable oil and / or vegetable oil-derived fatty acid ester is suitable, and as the vegetable oil, soybean oil, cottonseed oil, linseed oil, safflower oil are preferred. Examples thereof include dry oils or semi-dry oils such as tung oil, tall oil, dehydrated castor oil, canola oil, and the vegetable oil-derived fatty acid ester compounds include the above-mentioned vegetable oil-derived fatty acid monoalkyl ester compounds.

The fatty acid constituting the fatty acid monoester is preferably a saturated or unsaturated fatty acid having 16 to 20 carbon atoms, and stearic acid, isostearic acid, hydroxystearic acid, oleic acid, linoleic acid, linolenic acid, eleostearine. Examples thereof include acids. The alcohol-derived alkyl group constituting the fatty acid monoester preferably has 1 to 10 carbon atoms, and examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and 2-ethylhexyl. The vegetable oil component consisting of these vegetable oils and fatty acid monoesters, alone, depending on the required solubility and drying properties,
Alternatively, two or more kinds can be used in combination. The present invention is characterized by using a resin varnish (B) obtained by heating and dissolving such a rosin resin and a vegetable oil-modified alkyd resin together in a vegetable oil component in order to obtain an ink having high gloss. To this end, a rosin resin and a vegetable oil-modified alkyd resin are mixed in the vegetable oil component, and
A method of heating and dissolving at 0 to 300 ° C. for about 30 minutes to 2 hours can be used.

The preferable mixing ratio of the rosin resin and the vegetable oil modified alkyd resin is 100 to 100 parts by weight of the rosin resin and the vegetable oil modified alkyd resin is 10 to 100.
About 10 parts by weight, within this range, those with a large proportion of rosin-based resin gave good results in terms of settability, and those with a large proportion of vegetable oil-modified alkyd resin had good results in terms of luster. Is obtained. If necessary, a resin varnish gelated with a commonly used gelling agent can also be used, but with gel varnish using an excessive amount of gelling agent, fluidity and printing during ink formation It is preferable that the degree of gelation is kept to an appropriate degree, since it tends to cause defects such as suitability.

In the offset printing ink composition of the present invention, a vegetable oil component is post-added, if necessary, mainly for the purpose of adjusting viscosity, and the vegetable oil component added after this is referred to as the vegetable oil component (the C). Therefore, although the vegetable oil component (C) is a vegetable oil component other than the components contained in the resin varnish (B), the vegetable oil used for obtaining the resin varnish (B) and / or the vegetable oil derived from a fatty acid ester derived from the vegetable oil is a vegetable oil. The same components can be used.

In addition, as necessary, a pigment dispersant, a drier, a drying retarder, an antioxidant, an additive,
A surface conditioning agent, a friction resistance improver, a set-off preventing agent, a nonionic surfactant, etc. can be used as appropriate.

The ink composition for offset printing of the present invention is composed of the above materials, but when the vegetable oil component (C) is not contained, the resin varnish (B) is
At a temperature of 25 ° C., 1 g of the resin varnish (B) has a property of becoming cloudy when the addition amount of normal hexane is 2 g or less,
When the above-mentioned vegetable oil component (C) is contained, the above resin varnish (B) and the vegetable oil component (C) that is added as needed later are all resin varnishes contained in the ink composition. The mixture (D), which is a mixture of (B) and the vegetable oil component (C) in a ratio corresponding to the above, becomes cloudy at a temperature of 25 ° C. when the amount of normal hexane added is 2 g or less per 1 g of the mixture (D). It is necessary to have a property.

For example, an ink composition having the ink formulation of Example 1 described later has 18 parts by weight of pigment, 73 parts by weight of resin varnish (B), 2 parts by weight of additive, and 7 parts by weight of vegetable oil (C) after addition. The mixture (D) is 73 parts by weight of the resin varnish (B) and 7 parts by weight of the vegetable oil component (C), that is, the resin varnish (B): vegetable oil component (C).
= 91.2: 8.8, which means that the mixture is white and turbid at a temperature of 25 ° C. when the amount of normal hexane added is 2 g or less with respect to 1 g of the mixture (D). It is a thing. In Example 1 as described above, the amount of normal hexane added becomes 1.8 g, which causes cloudiness, but in other cases, the amount of normal hexane added when cloudy is determined based on Example 1 is determined. can do. When the amount of normal hexane added in this way exceeds 2 g, the required settability cannot be obtained, which is not preferable. In addition, in order to obtain an ink having a better gloss, it is preferable that the amount of the normal hexane added is less than 1.0 g so that no cloudiness occurs.

A conventionally known method can be used for producing the offset printing ink composition of the present invention using the materials exemplified above. For example, offset printing is performed by adding the pigment (A) and a pigment dispersant, which is added as necessary, to the resin varnish (B) for offset printing ink of the present invention, and dispersing the kneaded meat with a bead mill or a three-roll mill. Obtain an ink base. A method of obtaining an offset printing ink composition by adding a vegetable oil component (C) and an additive to the obtained base for offset printing ink to adjust it to a predetermined viscosity or viscosity, if necessary, may be mentioned.

The offset printing ink composition of the present invention is characterized by containing substantially no mineral oil component. However, since the additive contains mineral oil, a small amount of mineral oil is unavoidably offset. It may be contained in the printing ink composition. In such a case, as an environmental measure, it can be said that if the content of the mineral oil component is 3% or less, it is within the allowable range, but it is preferable to use the additive that does not contain the mineral oil component.

The offset printing ink composition of the present invention comprises
When the vegetable oil component (C) is not contained, the resin varnish (B) is used. When the vegetable oil component (C) is contained, the resin varnish (B) and the vegetable oil component added later are added. With respect to the mixture (D) of (C), by controlling the solubility of the resin-vegetable oil component using the amount of normal hexane added until it becomes cloudy as an index, a non-VOC ink containing only the vegetable oil component is obtained It has a settability. Further, the gloss is improved by using the resin varnish (B) obtained by simultaneously heating and dissolving a rosin-based resin and a vegetable oil-modified alkyd resin, and an offset printing ink composition having good settability and gloss, which are contradictory properties. Is.

[0027]

EXAMPLES The offset printing ink composition of the present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these without departing from the spirit and the scope of application thereof.

[Production of varnish for offset printing ink] (Varnishes 1 to 3, Comparative 2) A four-necked flask equipped with a condenser, a thermometer and a stirrer had a weight average molecular weight of 80.
000, acid value 20 mgKOH / g, rosin-modified phenol resin A (OR-560, trade name, manufactured by Seikou Kagaku), soybean oil-modified alkyd resin (SB-81, trade name, manufactured by Toshin Yushi Co., Ltd.), soybean oil or Soybean oil fatty acid isobutyl ester (manufactured by Nikka Gosei Co., Ltd.) was charged so as to have the blending ratios shown in Table 1 (blending amounts of each component are shown in parts by weight, the same applies hereinafter), and the temperature was raised to 210 ° C. It was heated and dissolved for an hour. When a gel varnish is used, ethyl acetate aluminum diisopropoxide (ALCH manufactured by Kawaken Fine Chemical Co., Ltd., trade name, the same applies below) is charged as a gelling agent so that the blending ratio is as shown in Table 1, and the mixture is heated and kept at 170 ° C. for 60 minutes. Then, a (gel) varnish for offset printing ink of Example A was obtained.

(Varnishes 4-5, Comparative 3) Production of varnish for offset printing ink: In (varnish 1), rosin-modified phenol resin A was added to a weight average molecular weight of 10,000.
A gel varnish for offset printing ink of Example E was obtained in the same manner as in Example A, except that the rosin-modified phenolic resin B (TS1317, trade name, manufactured by Hitachi Gosei Co., Ltd.) having an acid value of 15 mgKOH / g was used.

(Comparative 1) A four-necked flask equipped with a condenser, a thermometer and a stirrer was used, and a weight average molecular weight of 100 was used.
00, acid value 14 mgKOH / g rosin-modified phenolic resin C (TS1355, trade name, manufactured by Hitachi Gosei Co., Ltd.), soybean oil were prepared at the blending ratios shown in Table 1, and 21
After heating to 0 ° C. and heating and dissolving at the same temperature for 1 hour, ethyl acetate aluminum diisopropoxide was added as a gelling agent so as to have a blending ratio shown in Table 1, and heated and maintained at 170 ° C. for 60 minutes, A (gel) varnish for offset printing ink of Comparative 1 was obtained.

Gel varnish for offset printing ink of Examples 1 to 5, phthalocyanine blue (manufactured by Dainichiseika Co., Ltd., 49
27 EP, trade name, the same hereinafter), vegetable oil components and drying aids were mixed in the respective mixing ratios shown in Table 2 to form an ink. Comparative Examples 1 to 3 were also ink-formed in the same manner.

[Performance Evaluation Test] The offset printing ink compositions of Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated for printing performance as follows. [Setting property] After each offset printing ink composition is spread on coated paper with an RI tester (manufactured by Ming Seisakusho Co., Ltd.), ink is printed on high-quality paper using an automatic ink setting tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.). The degree of adhesion was observed, and the time (minutes) required until the ink did not adhere was measured. The shorter this time is, the better the setability is.

[Gloss] Each offset printing ink composition was spread on a coated paper with an RI tester (manufactured by Akira Seisakusho),
After left at room temperature for 1 day, the 60 ° -60 ° reflectance was measured by a gloss meter (Murakami Color Research Laboratory, digital gloss meter).

[Evaluation Results] Examples 1 to 5 and Comparative Examples 1 to 1
The offset printing ink composition of No. 3 is shown in Tables 1 and 2 for the above formulation, and the results of the above evaluations are shown in the lower part of Table 2.

[0035]

[Table 1]

[0036]

[Table 2]

In Table 2, normal hexane (g) means the resin varnish (B) and the vegetable oil component (C) which is added as needed later, in all the ink compositions. When a mixture (D) was prepared by mixing the resin varnish (B) and the vegetable oil component (C) at a ratio corresponding to each other, and normal hexane was added to 1 g of the mixture (D) at a temperature of 25 ° C. Represents the amount of normal hexane to be clouded (g).

[0038]

Since the offset printing ink composition of the present invention has the constitution as described above, it is a so-called non-VOC or low-VOC ink containing substantially no mineral oil component, It is a product that achieves both excellent environmental performance and ink performance that can exhibit excellent performance in both properties where gloss is contradictory.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Araki             Sakata, 1-23-37, Edobori, Nishi-ku, Osaka             Inkus Co., Ltd. (72) Inventor Takashi Kimura             Sakata, 1-23-37, Edobori, Nishi-ku, Osaka             Inkus Co., Ltd. (72) Inventor Koji Iwase             Sakata, 1-23-37, Edobori, Nishi-ku, Osaka             Inkus Co., Ltd. F-term (reference) 4J039 AB04 AB08 AD14 AE02 AE06                       BE01 BE12 EA33 EA48 GA01

Claims (3)

[Claims] 1. An offset printing ink composition containing substantially no mineral oil component, wherein the offset printing ink composition comprises a pigment (A) and a resin varnish (B) as essential components. The resin varnish (B) is a resin varnish obtained by heating and dissolving a rosin-based resin, a vegetable oil-modified alkyd resin and a vegetable oil component, and the offset printing ink composition contains the vegetable oil component (C) and the resin varnish (B ) May be contained as a vegetable oil component other than the component contained in the above), and when the vegetable oil component (C) is not contained, the resin varnish (B) is 1 g of the resin varnish (B) at a temperature of 25 ° C. The normal hexane content is 2
When it has a property of clouding at g or less and contains the vegetable oil component (C), all of the resin varnish (B) and the vegetable oil component (C) are contained in the offset printing ink composition. When the resin varnish (B) and the vegetable oil component (C) are mixed in a ratio corresponding to each other to form a mixture (D), the mixture (D) is normal to 1 g of the mixture (D) at a temperature of 25 ° C. An offset printing ink composition characterized in that it has a turbidity when the amount of hexane added is 2 g or less. 2. The offset printing ink composition according to claim 1, wherein the rosin-based resin is a rosin-modified phenol resin or a rosin-modified maleic resin. 3. The vegetable oil component (C) is a vegetable oil and / or
Alternatively, the offset printing ink composition according to claim 1, which is a fatty acid ester derived from vegetable oil.