JP2005154704A - Method for producing print ink resin varnish - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a print ink resin varnish easily, reasonably, and economically, wherein the print ink resin varnish contains a high molecular weight rosin modified phenol resin and is excellent in high speed printing performance. <P>SOLUTION: The method comprises heating to react (a) a low molecular weight rosin modified phenol resin with (b) a resol type phenol resin and/or a multifunctional acrylate in the presence of (c) a solvent for an offset print ink. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a method for producing a resin varnish for offset printing ink. Especially, it is related with the manufacturing method of the resin varnish for printing inks which is excellent in high-speed printing aptitude.

Conventionally, rosin-modified phenolic resins used in offset printing inks have been produced by a method of reacting rosins with a resole type fail resin and a polyhydric alcohol, a method of reacting a rosin ester resin with a resole type fail resin, and the like. . A bulk polymerization method in which these reactions are reacted at a temperature of 200 to 270 ° C. has been adopted. However, when synthesizing a high molecular weight rosin-modified phenol resin, the melt viscosity of the resin is high at the time of synthesis, and the load on the agitation equipment is large. Moreover, although high molecular weight resins generally tend to have a high softening point, there is a problem that such resins are difficult to take out of the reaction system.

On the other hand, a resin varnish for printing ink is manufactured by heating and dissolving the rosin-modified phenolic resin manufactured by the above method in an ink solvent and vegetable oil, adding a gelling agent if necessary, and performing cooking. I came. In the case of a rosin-modified phenolic resin having a relatively low molecular weight, this is not a big problem, but if a resin with a high molecular weight and a high softening point is dissolved in an ink solvent or vegetable oil, it will not be dissolved easily, and it will take time to manufacture. There were many.

In recent years, with the increase in the speed of offset printing, various high-speed printing aptitudes are also required for printing ink resins, and in particular, improvement of misting is the most important requirement. In other words, in order to suppress the occurrence of misting during printing, high viscosity, low tack inks are used, and rosin-modified phenolic resins with high molecular weight, high viscosity and high softening point are desired. Yes.

However, as mentioned above, rosin-modified phenolic resins with high molecular weight, high viscosity, and high softening point are overloaded to the stirring equipment of manufacturing equipment, difficult to take out the resin out of the reaction system, and for printing inks Due to problems such as annoyance during the production of the resin varnish, it was extremely difficult to produce the resin and a resin varnish for printing ink containing the resin.

The present invention provides a method for easily, rationally and economically producing a printing ink resin varnish excellent in high-speed printing, which contains a high-molecular-weight, high-viscosity, and high-softening point rosin-modified phenolic resin. The purpose is to do.

Means to solve the problem

In light of these circumstances, the present inventors have conducted extensive studies, and as a result, heat-reacted a low molecular weight rosin-modified phenolic resin, a resole-type phenolic resin and / or a polyfunctional acrylate in the presence of an ink solvent. Thus, it has been found that a resin varnish for printing ink, which contains a rosin-modified phenol resin having a desired high molecular weight, high viscosity, and high softening point and excellent in high-speed printing, can be obtained.

That is, the present invention relates to a printing ink in which a low molecular weight rosin-modified phenolic resin (I) and a resole type phenolic resin and / or a polyfunctional acrylate (B) are heated and reacted in the presence of a printing ink solvent (C). The present invention relates to a method for producing a resin varnish.

In the present invention, the rosin-modified phenolic resin (I) is prepared by reacting a rosin with a resole phenolic resin and then reacting the reaction product with a polyhydric alcohol, and reacting the rosin ester resin with a resole phenolic resin. It is obtained by the manufacturing method.

Examples of rosins used include gum rosin, wood rosin, tall oil rosin, polymerized rosin, disproportionated rosin, and hydrogenated rosin. Further, if necessary, these rosins can be used after modifying an unsaturated dibasic acid such as maleic acid or fumaric acid. The rosin ester resin can be obtained by reacting the rosin with a polyhydric alcohol. As the polyhydric alcohol to be used, conventionally known polyhydric alcohols are used. Mention may be made of methylolethane, pentaerythritol, dipentaerythritol and the like. The polyhydric alcohol is desirably 5 to 15 parts by mass with respect to 100 parts by mass of the rosins, and within this range, it is easy to keep the molecular weight of the resin within a desired range. The resol type phenol resin is obtained by mixing at a ratio of 1.5 to 3 moles of formaldehyde with respect to 1 mole of phenols and performing condensation polymerization in the presence of an alkali catalyst such as sodium hydroxide, potassium hydroxide or calcium hydroxide. It is done. If necessary, the alkali catalyst is neutralized and washed after the reaction. Here, conventionally known phenols are used, and examples thereof include carboxylic acid, cresol, bisphenol A, p-butylphenol, p-octylphenol, p-nonylphenol, and p-dodecylphenol. In addition, it is desirable that the resol type phenol resin is 10 to 100 parts by mass, preferably 20 to 70 parts by mass with respect to 100 parts by mass of rosin or rosin ester resin.

In the present invention, the weight average molecular weight of the rosin-modified phenolic resin (I) needs to be 2000 to 100000 and a relatively low molecular weight. When the viscosity is 2000 or less, it is difficult to obtain a high-viscosity varnish, and when it is 100,000 or more, it takes time to dissolve the varnish during production, and reaction management becomes difficult.

In the present invention, the resol type phenol resin (B) is obtained in the same manner as described above. 10 to 100 parts by weight, preferably 20 to 70 parts by weight, based on 100 parts by weight of the rosin-modified phenol resin (ii). In the present invention, a conventionally known polyfunctional acrylate (b) is used. For example, ethylene glycol diacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate. And pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and the like. The polyfunctional acrylate is preferably about 0.1 to 20 parts by weight with respect to 100 parts by weight of the rosin-modified phenolic resin (ii), and within this range, the molecular weight of the resin falls within the expected range. Is easy.

In the present invention, as the printing ink solvent (c), an offset printing ink solvent having a boiling point of 200 ° C. or higher can be used. As these solvents, for example, paraffinic and naphthenic petroleum ink solvents are used. Preferable examples include ink solvents such as AF5 solvent, AF6 solvent, AF7 solvent manufactured by Nippon Oil Corporation.

Vegetable oil can also be added to the resin varnish for printing ink of the present invention. Preferred examples of vegetable oils include drying oils such as linseed oil, tung oil, safflower oil, semi-drying oils such as soybean oil, rapeseed oil, and corn oil, non-drying oils such as castor oil and olive oil, dehydrated castor oil, and thermal polymerization oil. Synthetic drying oils, and mixtures and regenerated oils thereof can be mentioned. Moreover, fatty acid ester etc. can also be used together as needed. In addition, 10-50 mass parts is suitable for the compounding quantity of vegetable oil with respect to 100 mass parts of solid content in a varnish.

The resin varnish for printing ink of the present invention can be heated and reacted by adding a gelling agent as necessary. Preferable examples of the gelling agent include known ones such as aluminum ethyl acetoacetate diisopropylate, aluminum tris (ethyl acetoacetate), aluminum isopropylate, aluminum stearate, aluminum octylate, and mixtures thereof are also used. can do. In addition, 0-5 mass parts is suitable for the compounding quantity of a gelatinizer with respect to 100 mass parts of solid content in a varnish. After adding the gelling agent, it is appropriate to react at about 150 to 180 ° C. for about 1 to 2 hours.

In the present invention, the rosin-modified phenolic resin (I) and the resol type phenolic resin and / or the polyfunctional acrylate (B) are heated and reacted in the presence of the printing ink solvent (C), and the temperature is 100 to 270 ° C. Is suitable, and 140-230 degreeC is more preferable. Moreover, it is made to react on the pressure reduction conditions of 500 mmHg or less as needed.

The invention's effect

According to the method for producing a resin varnish for printing ink of the present invention, a resin varnish for printing ink containing a rosin-modified phenolic resin having a high molecular weight, a high viscosity, and a high softening point can be easily and rationally and economically produced. it can. According to the present invention, a rosin-modified phenol resin having a high molecular weight, a high viscosity, and a high softening point can be obtained as compared with a bulk polymerization method in which a rosin-modified phenol resin is reacted in a conventional molten state. Therefore, it contributes to the cost reduction of the resin varnish for printing ink.

Hereinafter, the present invention will be described in detail by way of examples. In addition, the part of preparation represents a mass part.

[Synthesis Example 1]
Charge 800 parts of Chinese gum rosin into a reaction vessel equipped with a stirrer and water separator, heat and stir while blowing nitrogen gas, charge 80 parts of pentaerythritol and 2 parts of magnesium acetate at 200 ° C, and perform dehydration condensation at 270 ° C. The rosin ester resin was synthesized by reacting until the acid value reached about 20.

[Synthesis Example 2]
In a reactor equipped with a stirrer and a cooler, 400 parts of p-octylphenol, 140 parts of paraformaldehyde (purity 92%) and 1 part of sodium hydroxide are charged, heated to 90 ° C. and reacted for 5 hours to obtain a resol type phenol resin. It was.

[Synthesis Example 3]
In a reaction vessel equipped with a stirrer and a water separator, 800 parts of the rosin ester resin synthesized in Synthesis Example 1 was charged, heated and stirred while blowing nitrogen gas, and 240 parts of resole phenolic resin synthesized in Synthesis Example 2 at 240 ° C. Was dropped. The obtained rosin-modified phenolic resin has a softening point of 140 ° C., an acid value of 15 mg KOH / g, a hydroxyl value of 60 mg KOH / g, an AF7 solvent (manufactured by Shin Nippon Oil Co., Ltd.), solubility 4.5 times, and a weight average molecular weight of 4000. . The AF7 solvent solubility means that 2 g of resin is dissolved in 4 g of AF7 solvent, and AF7 solvent is added in order, and the resin dissolves in the number of grams of AF7 solvent used until the start of cloudiness. 4 g of the AF7 solvent used in the above is added to indicate how many times the AF7 solvent is used per 1 g of resin.

[Synthesis Example 4]
In a reaction vessel equipped with a stirrer and a water separator, 800 parts of the rosin ester resin synthesized in Synthesis Example 1 was charged, heated and stirred while blowing nitrogen gas, and 320 parts of resole phenolic resin synthesized in Synthesis Example 2 at 240 ° C. Was dropped. The obtained rosin-modified phenolic resin has a softening point of 170 ° C., an acid value of 15 mg KOH / g, a hydroxyl value of 65 mg KOH / g, an AF7 solvent (manufactured by Shin Nippon Oil Co., Ltd.), a solubility of 3.5 times, and a weight average molecular weight of 30000. .

[Example 1]
In a reaction vessel equipped with a stirrer and a water separator, 700 parts of the rosin-modified phenol resin synthesized in Synthesis Example 3, 100 parts of the resole-type phenol resin synthesized in Synthesis Example 2 and 300 parts of AF7 Solvent were charged and heated while blowing nitrogen gas. Stir to dissolve the resin. Thereafter, while raising the temperature to 230 ° C., water generated by the condensation reaction between the rosin-modified phenol resin and the resol type phenol resin was recovered with a water separator. After reacting at 230 ° C. for 3 hours, 200 parts of AF7 solvent, 220 parts of soybean oil and 8 parts of ALCH-50F (manufactured by Kawaken Fine Chemical Co., Ltd.) are added, and further reacted at 180 ° C. for 1 hour to form a resin varnish ( Resin solid content 50%) was obtained.

[Example 2]
A resin varnish (resin solid content 50%) was synthesized in the same manner as in Example 1 except that 750 parts of the rosin-modified phenol resin synthesized in Synthesis Example 4 and 50 parts of the resole-type phenol resin synthesized in Synthesis Example 2 were used. Obtained.

[Comparative Example 1]
450 parts of Chinese gum rosin was charged in the same reaction vessel as in Example 1, and heated and stirred while blowing nitrogen gas, and 400 parts of a resol type phenolic resin synthesized in Synthesis Example 2 was added dropwise at 230 ° C. in 3 hours. Thereafter, 40 parts of glycerin and 0.4 part of magnesium oxide were added and subjected to dehydration condensation at 270 ° C. until the acid value reached about 20. The obtained rosin-modified phenolic resin has a softening point of 175 ° C., an acid value of 15 mg KOH / g, a hydroxyl value of 75 mg KOH / g, an AF7 solvent (manufactured by Shin Nippon Oil Co., Ltd.), a solubility of 1.6 times, and a weight average molecular weight of 80000. . Thereafter, 500 parts of AF7 solvent, 220 parts of soybean oil and 16 parts of ALCH-50F were added and reacted at 180 ° C. for 1 hour to obtain a resin varnish (resin solid content 50%).

[Comparative Example 2]
In a reaction container similar to that in Example 1, 400 parts of the rosin ester resin synthesized in Synthesis Example 1 and 400 parts of the resol-type phenol resin synthesized in Synthesis Example 2 were dropped in 3 hours. The obtained rosin-modified phenolic resin has a softening point of 170 ° C., an acid value of 15 mg KOH / g, a hydroxyl value of 65 mg KOH / g, solubility of AF7 solvent (manufactured by Shin Nippon Oil Co., Ltd.), 4.4 times, and a weight average molecular weight of 50,000. . Thereafter, 500 parts of AF7 solvent, 220 parts of soybean oil and 25 parts of ALCH-50F were added and reacted at 180 ° C. for 1 hour to obtain a resin varnish (resin solid content 50%).

About the obtained resin varnish, a viscosity, n-hexane solubility, and the weight average molecular weight were measured. The measurement was performed by the following method, and the results are shown in Table 1.

Viscosity: Measurement was carried out using an E-type viscometer at 25 ° C. and a rotation speed of 10 rpm.

n-Hexane solubility: n-hexane was added dropwise to 1 g of varnish at 25 ° C. while mixing, and the amount of n-hexane dropped when the solution started to become cloudy was defined as n-hexane solubility.

Weight average molecular weight: The molecular weight (polystyrene conversion) was measured by GPC analysis.

For each resin varnish in Table 1, 60 parts of varnish and 36 parts of Carmine 6B are kneaded with a three-roll mill and adjusted with each varnish and AF No. 7 solvent so that the tack is 6 to 7 and the flow is 30 to 35 mm / min. Thus, a red ink for test was obtained.

Table 2 shows the properties and evaluation results of each ink.

The ink performance evaluation in Table 2 was performed as follows.

Tack: Measured using a digital incometer (manufactured by Toyo Seiki Seisakusho).

Flow: Measured using a parallel plate viscometer (manufactured by Toyo Seiki Seisakusho).

Gloss: After 0.3 cc of ink was developed on art paper with an RI tester (Made Seisakusho), it was dried in a hot air dryer at 120 ° C. for 5 seconds, and after 24 hours at room temperature, a gloss meter (Gardner) The specular reflectance at 60 ° was measured using

Emulsification rate: Using Lysotronic (manufactured by Novomatic), ion-exchanged water was added dropwise to 25 g of ink at a rate of 2 ml / min, and the emulsification rate when saturated was measured.

Misting amount: The amount of mist splashed below the roll was precisely weighed when 1.3 cc of ink was rotated at 2000 rpm per minute for a digital incometer (manufactured by Toyo Seiki Seisakusho).

From Table 2, the ink using Example 1 and Example 2 is equivalent or better in all evaluation items compared with the ink using Comparative Example 1 and Comparative Example 2 (dissolving conventional rosin-modified phenolic resin). In particular, it has excellent performance in terms of emulsification rate and misting resistance.

Claims (1)

A process for producing a resin varnish for printing ink, in which a low molecular weight rosin-modified phenolic resin (I), a resol type phenolic resin and / or a polyfunctional acrylate (B) are heated and reacted in the presence of a printing ink solvent (C).