JPH083068B2 - Ink for dry lithographic printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Object of the Invention" (Field of Industrial Application) The present invention relates to a dry lithographic printing ink.

(Prior Art) Currently, as general printing methods, letterpress printing, planographic printing,
There are intaglio printing, etc. Among the lithographic printing, in wet offset printing, the printing plate surface consists of a hydrophilic part and a lipophilic part,
This is a method in which the ink is transferred only to the lipophilic part to obtain a streak. The features of this printing method are that images are clear, high-quality printed matter can be obtained, plate making price is low, and plate making can be done in a short time. However, in this printing method, the dampening water is used together with the ink at the time of printing, so that it is necessary to control the dampening water as well as the control of the ink, and the printing work requires a high technique. For this reason, a printing method has been proposed recently that enables lithographic offset printing without using dampening water. That is, it is a dry lithographic printing, and the printing by this method has problems such as emulsification of printing ink, transfer failure due to water loss, occurrence of ghosting, etc. which are problems at the time of conventional wet offset printing. Be improved.

However, when printing is continued for a long time by this dry lithographic printing method using ordinary ink, the temperature on the plate surface rises, and the ink easily adheres to the non-image area to cause stains. As a means for solving this, a means for modifying various ink materials with a silicon compound has been proposed. For example, silicon-modified alkyd resin (Japanese Patent Publication No. 51-10124, No. 51-22405), silicon-modified phenol resin (Japanese Patent Laid-Open No. 52-10042, 52-62506), silicon-modified drying oil ( Japanese Patent Publication Nos. 52-10041 and 52-10042) Silicon-modified cyclopentadiene resin (JP-A-56-56)
-11024 and 56-110706), and an ink using a solvent of a low aromatic olefin component (JP-A-56-82861). Although these materials show an effect on stains, depending on the combination, stain resistance is still unsatisfactory, or the background stain resistance is improved and the gloss of the printed matter deteriorates, and the quality of the printed matter deteriorates. There are drawbacks. On the other hand, the problem with ink is that workability deteriorates because the ink thickens during storage. Furthermore, since siloxane compounds are much more expensive than general ink materials, there is a drawback that the price of ink also rises.

(Problems to be solved by the invention) In printing using a dry lithographic plate, there is scum resistance,
There has been a demand for a dry lithographic printing ink that has excellent gloss, is inexpensive, and has excellent stability during storage.

“Structure of the Invention” (Means for Solving Problems) The inventors of the present invention have studied a dry lithographic printing ink that is resistant to scumming, has excellent gloss, has excellent storage stability, and is inexpensive. , A resin component obtained by reacting a resol type phenolic resin with a double bond of rosin, and a resin component obtained by esterifying the remaining phenolic resin such as a resole type phenolic resin and / or a novolac type phenolic resin with a carboxyl group of rosin Rosin-modified phenolic resin with an acid value of 40 or less
℃ below, aniline point 75 ~ 85 ℃, boiling point above 230 ℃,
A dry lithographic printing ink containing a varnish dissolved in an ink solvent having an aromatic hydrocarbon content of 10% by weight or less was invented.

INDUSTRIAL APPLICABILITY The rosin-modified phenolic resin of the present invention is inexpensive, can control the molecular weight suitable for offset printing ink, and has been studied for the synthesis of rosin-modified phenolic resin having good printability for offset printing. In the rosin-modified phenolic resin obtained by the reaction, the resole-type phenolic resin that is a part of the phenolic resin reacts with the double bond present in the rosin molecule and becomes a resin-like polybasic acid (mainly dibasic acid). Become. Furthermore, a dry lithographic printing ink containing as a varnish component a rosin-modified phenolic resin having an acid value of 40 or less by an esterification reaction of this reaction product and a resol-type and / or novolac-type phenolic resin in the presence of an acidic catalyst is provided. I found it. The order of the reactions can be reversed.

That is, in the reaction under acidic catalyst, the resole-type or novolak-type phenolic resin as the polyol component is rosin and the mixture of the above-mentioned resole-type phenolic resin and the resinous polybasic acid resulting from the reaction of rosin with ester at a temperature of 150 ° C or higher. It is a resin for printing ink that undergoes a chemical reaction to give an acid value of 40 or less, preferably 30 or less.

Examples of rosin include gum rosin, wood rosin, tall oil rosin, disproportionated rosin, etc. Also, combined use of rosin derivatives such as polymerized rosin, maleated rosin, fumarized rosin, C6-18 fatty acids, and polymerized dry oil fatty acids Is also possible if necessary.

The phenol resin used in the present invention is a resol type,
Regardless of novolac type, pt-butylphenol, p-
Phenolic resins obtained by condensation of phenol with p-formaldehyde mainly containing at least one selected from octylphenol and p-nonylphenol are preferable. Of course, other phenols can be used. For the resol type condensate, alkali such as sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium oxide, ammonia water, amines such as 1-ethylamine, triethanolamine and triethylenediamine can be used as reaction catalysts. it can.

Further, known reaction catalysts such as sulfuric acid, hydrochloric acid, oxalic acid and p-toluenesulfonic acid can be used for the synthesis of the novolak type condensate.

Next, the weight ratio of the rosin and the phenol resin of the rosin-modified phenol resin of the present invention is preferably 30 to 150 phenol resin to 100 rosin. If the amount of phenolic resin is less than this range, the molecular weight of the resin will decrease and the softening point will also decrease. If it exceeds 150, the molecular weight becomes high, and as a result, the solubility in the ink solvent deteriorates. Further, the ratio of the phenol resin reacted with the rosin in the present invention is such that the ratio of the phenol resin which reacts with the double bond of the rosin without a catalyst and the phenol resin which is esterified with the carboxylic acid in the presence of an acidic catalyst is 1: 0.8 by weight. ~ 1: 4 is desirable. If the amount of phenolic resin that reacts with the double bond of rosin without catalyst is more than this range, the hydroxyl groups required for esterification will be insufficient, making it difficult to lower the acid value and requiring a separate esterification step. , Offset printability is insufficient. On the other hand, when the amount is less than this range, the production of crosslinkable resinous polybasic acid is reduced and the molecular weight is lowered.

The acid value of the resin indicates the residual amount of free carboxyl groups, and if the residual amount is large, it is not preferable for offset printing suitability, and it is necessary to react until the acid value becomes 40 or less, preferably 30 or less.

To obtain the rosin-modified phenolic resin of the present invention, p
-Toluenesulfonic acid, dodecylbenzenesulfonic acid,
Esterification reaction between rosin and resole-type or novolac-type phenol resin must be carried out by heating above 150 ° C using sulfonic acids such as methanesulfonic acid and ethanesulfonic acid, and mineral acids such as sulfuric acid and hydrochloric acid as catalysts. However, the reaction product is easily colored under these conditions,
Reducing agent hypophosphorous acid, triphenylphosphite,
A combined use of triphenyl phosphate and the like is preferable.

The reaction sequence of the rosin and the phenolic resin is such that the double bond in the rosin molecule is first reacted with the resol type phenolic resin without catalyst, and then an acid catalyst is added to the resol type and / or novolac type phenolic resin to react with the carboxyl group of the rosin. Method, the carboxyl group of rosin is first reacted with a resole-type or novolak-type phenol resin under an acidic catalyst to neutralize the acid catalyst, and then a resole-type phenol resin is added to react with the double bond. It is also possible to do so.

However, the step (1) requires an alkaline substance for catalyst neutralization, and the step (1) is more advantageous because it leaves a salt due to neutralization.

Further, the resin for a dry lithographic printing ink of the present invention has a high melting point and a high solubility obtained by an esterification reaction of a rosin-modified phenol resin, an alkyd resin, a petroleum resin, and a rosin and a phenol resin which have been conventionally used for printing inks. It can be used in combination with rosin-modified phenolic resin, or modified with some petroleum resin or acrylic.

The solvent used in the dry lithographic printing ink of the present invention has a pour point of -10 ° C or lower and an aniline point of 75 to 85 ° C.
Boiling point is over 230 ℃, aromatic hydrocarbon content is 10% by weight
The following ink solvents are preferred. One of the conventional solvents has a high aromatic hydrocarbon content, and the ink for dry lithographic printing using this has insufficient resistance to scumming. The aromatic hydrocarbon content is 10% by weight or less, but the aniline point is 85 ° C or higher and the pour point is high at 5 ° C, which deteriorates the gloss of the ink and preserves it in winter or for a long time. It was a solvent lacking stability. In order to eliminate the disadvantages associated with these conventional solvents, the pour point is as low as -10 ° C or lower to maintain the viscosity stability in winter. When the aniline point is lower than 75 ° C, the gloss is good but the stain resistance is insufficient. Also, if the temperature is higher than 85 ° C, the gloss deteriorates and the storage stability is poor. There is also a relation between the soil resistance and the aromatic hydrocarbon content, and when the content is 10% by weight or more, the soil resistance becomes insufficient. When the boiling point is lower than 230 ° C, the stability on the printing press is poor, and accidents such as peeling of paper may occur during continuous printing for a long time.

The dry lithographic printing ink of the present invention comprises, in addition to 20 to 60% by weight of a rosin-modified phenolic resin and 20 to 60% by weight of an ink solvent, a drying oil such as linseed oil, tung oil or rice bran oil and / or a polymerized oil thereof. -30% by weight of varnish, and further this varnish using a known gelling agent such as aluminum octylate, aluminum stearate, zirconium octylate, aluminum triisopropoxide, and aluminum diisopropoxide monoacetyl acetate. Is desirable.

If necessary, organopolysiloxane can be added. The amount added is preferably less than 5% by weight, and the addition of more than that deteriorates the gloss. Examples of the organopolysiloxane include methylpolysiloxane, methylphenylpolysiloxane, dimethylpolysiloxane, and alkylallyl-modified silicone oil.

Also, as a colorant, pigments such as yellow, crimson, indigo, or black are dispersed, and if necessary, compounds such as an anti-friction agent, an ink dryer and a drying inhibitor are added to adjust the viscosity to an appropriate level. By doing so, it becomes a sheet-fed dry lithographic printing ink and an off-wheel dry lithographic printing ink.

The present invention will be described below with reference to specific examples. "Part",
"%" Represents parts by weight and% by weight, respectively.

Production Example 1 (Production of Resol-type Phenolic Resin) Stirrer, reflux condenser with water separator, 4-port flask with thermometer, p-octylphenol 170 parts, pt-butylphenol 22 parts, 35% formalin 170 parts, 93% After adding 12 parts of sodium hydroxide and 100 parts of tap water and heating to 90 ° C and reacting for 4 hours, 200 parts of toluene was added to dissolve the phenol resin in toluene, and 25 parts of 6N hydrochloric acid was added to 200 parts of tap water. The mixture was diluted and added, neutralized, allowed to stand, the aqueous layer was removed, then washed twice with 200 parts of water to PH5 to 6, and then the toluene layer was collected. The toluene solution of this phenol resin has a nonvolatile content of 50%
The yield was 420. This resol type phenol resin solution is referred to as A resol solution.

Production Example 2 In the process shown in Production Example 1, the phenol component (p-octylphenol 170 parts, pt-butylphenol 22 parts) was added to p.
In the same manner as above, except that the amount of octylphenol was changed to 200 parts, 400 parts of a resole type phenol resin solution (B resole solution) having a nonvolatile content of 49% was obtained.

Production Example 3 (Production of Novolac Phenolic Resin) A flask similar to that shown in Production Example 1 was charged with 170 parts of p-octylphenol, 22 parts of pt-butylphenol, 60 parts of 35% formalin, 2 parts of oxalic acid, and 90 ° C. After heating to 90
After reacting for 5 minutes, add 5 parts of hydrochloric acid and stir for 120 minutes at 90 ℃ to add 200 parts of water.
After adding 20 parts for 20 minutes, the mixture was left for 1 hour. Then, remove water, add 200 parts of water again, stir for 20 minutes, leave for 30 minutes to remove water, add 180 parts of xylene, stir for 2 hours at 110 ° C., and add A novolak with a nonvolatile content of 50%. A liquid was obtained.

Production Example 4 The phenol component (170 parts of p-octylphenol, 22 parts of pt-butylphenol) was pt in the process shown in Production Example 3.
-A B novolak solution having a nonvolatile content of 45% was obtained by the same steps except that 200 parts of butylphenol was replaced.

Production Example 5 (Production of rosin-modified phenolic resin) Stirrer, condenser with water separator, four-necked flask with thermometer were charged with 200 parts of Chinese gum rosin, heated while blowing nitrogen gas, and melted and stirred below 200 ° C. 260 ° C
Heat up to 120 parts of B resol solution was added dropwise over 1 hour, during which toluene in the resol solution was collected through a condenser with a water separator and the temperature was kept at 260 ° C. After that, the mixture is stirred at 260 ° C. for 2 hours, 280 parts of B resol solution and 1.2 parts of a mixed esterification catalyst of sulfuric acid / hypophosphorous acid = 3/7 are thoroughly mixed and added dropwise over 1 hour. During this period, toluene and water (reaction dehydration by esterification) were collected through a condenser with a water separator to keep the temperature at 260 ° C. After that, the mixture was reacted for 6 hours and was pumped out when the acid value reached 20.

This rosin-modified phenolic resin had an acid value of 20, a weight average molecular weight of 23.200 (by GPC method), and a melting point of 158 ° C (capillary method).

Production Example 6 In the same reactor as in Production Example 1, 120 parts of B resol solution was reacted with 200 parts of rosin without a catalyst, and B novolak solution was acidified to 24 in the same process as in Example 1 under an acidic catalyst. Reacted.

This resin has an acid value of 24, a weight average molecular weight of 18700 and a melting point of 1
It was 52 ° C.

Production Example 7 200 parts of Chinese gum rosin were charged in the same apparatus as in Production Example 1, heated while blowing nitrogen gas, melted and stirred at 200 ° C or lower, and at 240 ° C, 120 parts of A resol solution was added dropwise over 1 hour. After reacting for 2 hours, 200 parts of A resol solution and p-
Toluene sulfonic acid / hypophosphorous acid = 1/1 catalyst solution 1.2 parts was mixed well and added dropwise to the reaction system at 240 ° C over 1 hour.
After stirring for 30 minutes, an acid value of 23 was pumped out.

The acid value of this resin is 23, weight average molecular weight 22800, melting point 163 ° C.
Met.

Production Example 8 In the same process as in Production Example 7, 200 parts of Chinese gum rosin and 120 parts of A resol solution were reacted without a catalyst, and then A novolak solution 2
00 parts and 2.5 parts of an esterification catalyst of p-toluenesulfonic acid / hypophosphorous acid = 1/1 were mixed well, added dropwise and subjected to an esterification reaction for 8 hours, and an acid value of 26 was pumped out.

The acid value of this resin is 26, weight average molecular weight 19700, melting point 159 ° C.
Met.

Example 1 (Production of dry lithographic printing ink with good background stain resistance, gloss, and storage stability) 400 parts of rosin-modified phenolic resin obtained in Preparation Example 5, No. 00 linseed oil polymerized oil 80 parts, Exol D100 (Exxon Chemical 320 parts of a system ink solvent) was charged into a flask equipped with a stirrer and a thermometer, heated and stirred at 180 ° C. for 30 minutes and then cooled to obtain a varnish 1. Gel varnish 1 was obtained by gelling 800 parts of varnish 1 with 16 parts of octope Al (gelling agent manufactured by Hope Pharmaceutical Co., Ltd.).

Example 2 In the same manner as in Example 1, 400 parts of resin obtained in Production Example 6 was added.
No. linseed oil 80 parts of polymerized oil, 320 parts of Naphthesol H (Nippon Petrochemical Ink Solvent) were used to obtain varnish 2, and 800 parts of varnish 2 and 16 parts of octope Al were used to obtain gel varnish 2.

Example 3 In the same manner as in Example 1, 400 parts of the resin obtained in Production Example 2 was added.
No. linseed oil 80 parts of polymerized oil, 100 parts of Exosol D110 (exxon chemical ink solvent), 100 parts of PKWF28 / S1 (Hartmann GMBH solvent) to obtain varnish 3 and 800 parts of this varnish
A gel varnish 3 was obtained with 12 parts of AlCH (Kawaken Fine Chemicals gelling agent).

Comparative Example 1 (Preparation of varnish from conventional resin and naphthenic solvent) 200 parts of Chinese gum rosin were charged in the same reactor as in Production Example 1, heated while blowing nitrogen gas, and stirred at 200 ° C and further 230 ° C. The temperature was raised to 150 ° C and 150 parts of Hitachinol 2501 (p-octylphenol resol-type phenol resin manufactured by Hitachi Chemical) was added over 2 hours, and the reaction was conducted for 2 hours at the same temperature, the acid value was 83, and esterification occurred. Not not. After this, 17.5 parts of glycerin (OH group / COOH group = 1.1 / 1)
After the addition, the temperature was raised to 260 ° C and the reaction was carried out for 8 hours to obtain an acid value of 24.

The acid value of this resin was 24 and the melting point was 134 ° C. This rosin-modified phenolic resin is referred to as Comparative Resin I.

175 parts of this resin, No. 00 linseed oil 40 parts of polymerized oil, Exol
Comparative varnish 1 and comparative gel varnish 1 were obtained by the same process as in Example 1 using D100.

Comparative Example 2 (when a conventional paraffinic solvent is used) In the same manner as in Example 1, the rosin-modified phenolic resin obtained in Production Example 5 180 parts, No. 00 linseed oil polymerized oil 40 parts, Nisseki No. 0 solvent H ( A varnish and a gel varnish were prepared by using 180 parts of normal petroleum-based solvent (Nippon Petrochemical Co., Ltd.) to prepare Comparative Varnish 2 and Comparative Gel Varnish 2, respectively.

Comparative Example 3 Rosin-modified phenolic resin I1 in the process shown in Production Example 3
Comparative varnish 3 and comparative gel varnish 3 were obtained in exactly the same process except that 80 parts of the comparative resin I was replaced with 180 parts of the comparative resin I.

[Creation of ink]

Ink is 65 parts of each gel varnish, Carmin 6BA
180 parts (red pigment manufactured by Toyo Ink Mfg. Co., Ltd.) were dispersed using a three-roll mill, and each was made into an ink using the varnish and gel varnish, and the ink solvent used at the time of forming the varnish.

Example 4 is an example in which the gel varnish 1 was used to add an organopolysiloxane (Shin-Etsu Silicon KF96 manufactured by Shin-Etsu Silicon), and Comparative Example 4 was an example in which the comparative gel varnish 1 was used to add an organopolysiloxane.

[Ink evaluation]

These inks were printed using a dry lithographic plate, and the background temperature and gloss of the printed matter were measured. That is, a dry lithographic plate having a non-adhesive layer made of silicone rubber was attached to a printing machine modified by installing an electric heater on the plate cylinder to raise the plate surface temperature, and the plate surface temperature was supplied without supplying dampening water. The printing was performed while increasing the value, and a constant solid density was measured. The results are shown in the table.

For gloss, place the printed matter in an oven at 160 ° C for 5 seconds and heat it, then use the gloss meter model Murakami DM-26D (60-6
It was measured in 0).

Furthermore, the storage stability of the ink is as follows:
The hardness was examined by pushing it from above the perch with a finger at 25 ° C.

Claims (5)

[Claims] 1. A resin component obtained by reacting a resol-type phenol resin with a double bond of rosin, and a resin component obtained by esterifying a resol-type phenol resin and / or a novolac-type phenol resin with a carboxyl group of rosin. The rosin-modified phenolic resin having an acid value of 40 or less has a pour point of −20 ° C. or less and an aniline point of 75 to 85.
℃, boiling point 230 ℃ or more, aromatic hydrocarbon content is 10
An ink for dry lithographic printing, which comprises using a varnish dissolved in an ink solvent of not more than wt%. 2. The resol type phenol resin or novolac type phenol resin is pt-butylphenol, p.
The dry lithographic printing ink according to claim 1, which is a condensate of formaldehyde mainly containing at least one selected from octylphenol and p-nonylphenol. 3. The dry lithographic printing ink according to claim 1, wherein the weight ratio of rosin to phenol resin in the rosin-modified phenol resin is 30 to 150 with respect to 100 rosin. . 4. The weight of a phenol resin to be reacted with a rosin, which is a resol type phenol resin which reacts with a non-catalyst rosin double bond and a resole type or novolak type phenol resin which reacts with a carboxyl group of rosin under an acidic catalyst. The dry lithographic printing ink according to any one of claims 1 to 3, wherein the ratio is 1: 0.8 to 1: 4. 5. The dry lithographic printing ink according to any one of claims 1 to 4, further comprising an organopolysiloxane.