JPH04507B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an ink composition for waterless lithographic printing which has good background stain resistance and excellent printability in waterless lithographic printing. (Prior art) In contrast to the current mainstream printing method, which uses the ink repellency of dampening water, a waterless planographic printing method that uses a planographic printing method that does not require dampening water has been proposed. In particular, a method of printing using a lithographic printing plate having silicone rubber in the non-printing area has been put into practical use. It is known that when conventional oil-based ink is used in such waterless planographic printing, scumming occurs, which is undesirable. The phenomenon of scumming in waterless planographic printing is caused by the friction of the printing press's drive unit and rollers during printing, which causes the temperature of the plate surface to rise and the cohesive force of the ink itself to decrease, which is due to the fact that the ink itself is not naturally repellent. The ink adheres to the non-image area where it should be. Such a phenomenon does not need to be considered at all in conventional lithographic printing using dampening water, and is a problem unique to waterless lithographic printing plates. This is because in the case of conventional lithographic printing that uses dampening water, the ink repulsion mechanism is different, and the increase in plate surface temperature is considerably suppressed by the evaporation of dampening water, so there is no need to take this scumming phenomenon into consideration. It is said that it is preferable for the ink to have a small cohesive force. In order to improve this problem, it is possible to consider a method of increasing the molecular weight of the binder resin component to increase the cohesive force and improve the dirt resistance. However, even if the resin component in oil-based ink is made to have a high molecular weight using conventional methods, it still has good stain resistance and printability.
Furthermore, it is difficult to obtain waterless lithographic inks that give good printed matter. (Problems to be Solved by the Invention) The present invention was devised in view of the various shortcomings of the prior art, and its purpose is to create an ink composition for waterless planography that has excellent background stain resistance and printability. It's about providing things. (Means for Solving the Problems) The object of the present invention is to dissolve a phenolic resin, a rosin-modified phenol, and a phenolic resin in a mixture of a hydrocarbon solvent having a boiling point of 200° C. or more and a drying oil or a semi-drying oil while heating and stirring. By an ink composition for waterless lithographic printing, comprising a modified resin obtained by elongating the molecular chain of at least one member selected from the group of resins, epoxy resins, and xylene resins with an amine compound containing active hydrogen. achieved. Hydrocarbon solvents with a boiling point of 200°C or higher used in the present invention include aliphatic and alicyclic solvents having 12 or more carbon atoms;
A wide range of aromatic hydrocarbons can be used, but petroleum solvents with a boiling point of 200 to 350°C, which are commonly used as oil-based ink solvents, are preferably used, such as paraffinic, isoparaffinic, α-olefinic, and naphthenic solvents. Examples include high boiling point petroleum solvents such as aromatic and aromatic paraffinic solvents. In the present invention, the drying oil has an iodine value of 130
The above animal and vegetable oils can be used, such as linseed oil, oiticica oil, eno oil, tung oil, dehydrated castor oil, etc., and polymers thereof; semi-drying oils include animal and vegetable oils with an iodine value of 100 to 130; Examples include cottonseed oil, soybean oil, sesame oil, rapeseed oil, and polymers thereof. The vehicle resin used in the present invention includes at least one selected from the group of phenolic resins, rosin-modified phenolic resins, epoxy resins, and xylene resins, and these may be used alone or in a mixture of two or more. I can do it. The amine compounds containing active hydrogen used as molecular chain extenders in the present invention include monoamines such as ethylamine, n-propylamine, n-butylamine, hexylamine, laurylamine, stearylamine, ethanolamine, allylamine, ethylenediamine, Diamines such as trimethylene diamine, tetramethylene diamine, pentamethylene diamine, and hexamethylene diamine, polyamines such as diethylene triamine, triethylene tetramine, and bishydroxydiethylene triamine, and amine adducts can be effectively used. In addition, amide compounds as amine derivatives include formic acid, acetic acid, propionic acid, itaconic acid,
Monocarboxylic acids such as caprylic acid, glycolic acid, acrylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linoleic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, Organic dicarboxylic acids such as speric acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, dimer acid, organic tricarboxylic acids such as trimellitic acid, 3,9-bis(2carboxyalkyl)2,4,8,10-tetra Examples include condensates of organic carboxylic acids such as oxaspiroundecane and the above-mentioned amines, diamines, polyamines, and the like. The active hydrogen-containing amine compound used in the present invention has the above-mentioned structural composition, but
In consideration of handling, safety, etc., polyamide resins are preferred, and polyamide resins composed of an acid having 6 to 60 carbon atoms and a polyamine are particularly preferably used in view of compatibility with the resin and solvent. The molecular weight of the above polyamide resin is 500~
The range is preferably 20000, more preferably 500~
The range is 10000. The modified resin of the present invention contains a vehicle resin or a mixture thereof and active hydrogen, which is dissolved under heating and stirring in a hydrocarbon solvent with a boiling point of 200°C or higher, in a drying oil or a semi-drying oil, or in a mixture thereof. It is obtained by reacting an amine compound, but the reaction conditions are usually at a temperature of 70~70℃.
The range is preferably 200℃, more preferably 100~
The temperature is 170℃, and the concentration of reactants is usually 5 to 80℃.
% by weight is desirable, more preferably 20-70% by weight
is good. This reaction can be carried out in the manufacturing process of a varnish composition for printing ink. First, the resin component, drying oil, and solvent are added and dissolved by heating. Then, an amine compound containing active hydrogen is added at a predetermined temperature, and the reaction is carried out. It is something that forces you to do something. In addition, these reaction systems may contain a polar solvent or the like as an ink varnish composition component, and if necessary,
It can also contain other ingredients. The reaction time can be arbitrarily selected depending on the required characteristics of the desired ink varnish composition, but is usually 0.1 to 3 hours, preferably 0.3 to 2 hours. The composition containing the modified resin according to the present invention is made into an ink by adding other known ink components conventionally used for lithographic printing. Such components include resin components added as necessary, such as phenolic resins, rosin-modified phenolic resins, alkyd resins, rosin esters, petroleum resins, maleic acid resins, and drying oils, semi-drying oils, etc. These may be simply added, or may be combined with the resin composition obtained in the present invention. Furthermore, known gelling agents such as organoaluminum compounds can be used. In addition, as a coloring agent when used as an ink, those used in conventional ink compositions, such as inorganic or organic pigments, are used. Furthermore, for example, wax, desiccant, grease,
Dispersants, fillers, and other known agents can be used as necessary. The ink kneaded using three rolls using the above-mentioned materials has a high scumming temperature, has excellent printability, and can be made into a well-balanced ink for waterless lithographic printing. (Example) The present invention will be specifically explained below using Examples, but the present invention is not limited thereto. Note that the numbers used in Examples and Comparative Examples are parts by weight. Example 1 37 parts of rosin-modified phenolic resin (weight average molecular weight based on polystyrene: 50,000), 20 parts of "Nippon Flax" No. 4 (drying oil manufactured by Toshin Yushi Co., Ltd.), No. 5 solvent (Nippon Oil Co., Ltd.) 40 parts of a hydrocarbon solvent (boiling point 270-310°C) were mixed under a nitrogen stream, heated and stirred at 200°C for 60 minutes, and then a condensate of dimer acid and diethylenetriamine (molar ratio 1:1) was mixed. Three parts of a polyamide compound (molecular weight: 5000) was added and reacted for 30 minutes. To 85 parts of the varnish thus obtained, 15 parts of "Seika First" Yellow 2340 (yellow pigment for ink manufactured by Dainichiseika Co., Ltd.) was added, and the mixture was kneaded with three rolls in a conventional manner. I got it. Example 2 42 parts of cyclopentadiene petroleum resin (weight average molecular weight 22,000), 16 parts of "Pure Marine Linseed Oil" No. 4, 5
After mixing 40 parts of No. No. Solvent under a nitrogen flow and heating to dissolve, 2 parts of diethylenetriamine was added while heating and stirring at 180°C, and the mixture was heated and stirred for 30 minutes. The ink varnish thus obtained was converted into an ink in the same manner as in Example 1 to obtain ink B. Example 3 In the composition of Example 1, a condensate of linoleic acid and hexamethylene diamine (molecular weight:
3000) to form a varnish and an ink in the same manner to obtain Ink C. Comparative Example 1 In Example 1, 40 parts of rosin-modified phenolic resin and no polyamide compound were used,
Ink D was obtained in the same manner as varnish and ink. Comparative Example 2 Ink E was obtained in the same manner as in Example 2 except that the petroleum resin was changed to 44 parts and diethylenetriamine was not used. Inks A to E obtained in the above Examples and Comparative Examples were evaluated for ink characteristics and printing characteristics using respective methods, and the results are shown in Table 1. (Ink characteristics and evaluation method) A waterless lithographic plate with a non-adhesive layer made of silicone rubber was attached to a printing machine that had been improved so that the temperature of the plate surface could be raised by passing hot water through the plate cylinder, and the printing machine was used to print a printing machine without supplying dampening water. , print while increasing the temperature of the printing plate,
The surface temperature at which background smear occurred on the printed matter at a constant solid density was defined as the background smear occurrence temperature. The higher the temperature at which background smear occurs, the more likely it is that smudge will occur in practical printing. Next, the fluidity (flow value) of these inks was measured using a spread meter at 30°C, and the tack value was measured using an inkometer. In addition, each ink was printed using a waterless lithographic plate, and the solid density of the printed matter was measured using a Macbeth reflection densitometer.
The gloss value at 0.95 was measured with a 60 degree specular reflection gloss meter. From this result, inks A and C based on the present invention were compared to blank ink D, and ink B
It can be seen that ink ink is superior to blank ink E in that it has a higher scumming temperature and a lower tack value. In practical printing tests, inks A and C were compared with ink D, and ink B was compared with ink E, and inks A, B, and C did not cause any stains on the paper surface, and did not cause any problems such as piling or peeling. Print

[Table] Rubble was suppressed. Also, when we measured the gloss of printed matter, we found that ink A, B, C,
Even though the ink had high stain resistance, it produced glossy printed matter equivalent to that of blank ink. (Effects of the Invention) A waterless lithographic ink composition containing the molecular chain extension resin according to the present invention as a binder resin component has good background stain resistance and excellent printability.

Claims (1)

[Claims] 1. Dissolved with heating and stirring in a mixture of a hydrocarbon solvent with a boiling point of 200°C or higher and a drying oil or a semi-drying oil,
A water-free product characterized by containing a modified resin obtained by elongating the molecular chain of at least one member selected from the group of phenolic resin, rosin-modified phenolic resin, epoxy resin, and xylene resin with an amine compound containing active hydrogen. Lithographic ink composition.