Process for the preparation of offset printing inks

The invention relates to a method for the production of offset printing inks and their flowable concentrates according to one-step process.

Inks are usually produced by solids such as color pigments and additives, by means of dissolvers or stirred media / three-roll mill aggregates in binders and liquids such as oils, dispersed, the binder solutions are previously obtained by boiling resins and various additives in oils. This Druckfarbenherstellprozeß is technically very complex, lengthy and energy-intensive.

According to the known prior art is as a feedstock for the production of printing inks at least one, but usually requires more binders certain rheology. To prepare the binder is a resin, but often heated for several different resins in an oil mixture for several hours to temperatures around 180 ° C with stirring. The energy input is usually via a heat transfer oil which is heated in a separate gas-or oil-fired plant, and the process is rendered inert. After cooling, is stored temporarily until Weitervararbeitung. To sufficiently to be able to deliver, keep the ink manufacturers that are necessary for the specific delivery assortment binder. Storage is usually in storage tanks that Behe to maintain the pumpability of the binder are izt. Alternatively, in containers, eg 200 l drums, stored, the contents of which is heated before use in a heat chamber to improve flowability. Changes the set during production rheology is may depend on time, temperature and composition of the gas overlay related during storage. Yield.

Further processing for printing ink is then as described above.

There has been no lack of trying to shorten this manufacturing process and simplify. Thus, a method is described for example in EP 0022746-A1, are mixed together with the pigments and certain thermoplastic resins in the melt, or with the addition of again to remove solvents to obtain pigmented resins as a raw material for printing inks; the process of color production from these pigmented resins itself is not described. In EP 0290108-B1, the pigmentation of thermoplastic binders in an extruder at temperatures above the melting point of the binder resin and adding a liquid diluent will be described shortly before or after leaving the extruder, for producing a printing ink base stocks.

Object of the present invention was to indicate a method which allows to simplify the production of offset printing inks without adversely affecting their quality further, and to achieve even an improvement in quality in certain cases.

Surprisingly, this task can be solved by the one-step process according to the invention.

The present invention is a process for the production of offset printing inks or their concentrates from the printing ink underlying single components, which is characterized in that the solid and liquid components combined together in a mixer, and are therein processed directly for offset printing ink or to the concentrate.

In the one-step process according to the invention, the product obtained in the processing temperatures of at least 70 ° C, the majority of the necessary energy for heating in the form of mechanical energy is introduced.

The viscosity of the inventively obtained offset printing ink or concentrate is generally between 10 and 300 Pas.

In the invention procedure is completely dispensed with the separate preparation of the binder. The Gesamtherstellprozess is seen so time is much shorter and greatly improves the reproducibility of the process due to the elimination of certain process steps and intermediate storage.

The pigments can be added as dry pigments or pigment precursors or in the form of a paste into the mixer.

The present invention also relates to offset printing inks, which were obtained by the method according to the invention, as well as the production of printed products according to the invention produced using offset printing inks.

The one step according to the invention for the production of offset printing inks can be much easier and more economical than perform the method of the known art. Furthermore, the printing inks according to the invention are characterized by improved quality, for example, in a reduction of Bronciereffektes shows (color change depending on the incident light).

For the inventive process is to be executed, the following details.

Among offset printing inks according to the invention are the usual for conventional offset printing processes such as sheet offset, web offset, fast-offset, continuous and sheet printing understood, the composition and combination of the raw materials in a wide range are variable. This also applies to the printing inks underlying solid and liquid components. The individual solid components can be introduced in powder or granular form or as pastes.

Suitable pigments are usually suitable for offset printing, for example, pigment black, phthalocyanine (CI 15), Rubin Toner (CI 57: 1), diaryl (CI 12 / CI 13) and the usual in the spot color area pigments. Further, fillers such as calcium carbonate and inorganic pigments can be used.

As hard resins, for example, <1 cm can be used in particle sizes, are, for example rosin resins, hydrocarbon resins, modified rosins, such as those which are modified with acrylic acid or maleic acid, modified hydrocarbon resins, for example those modified with rosin or phenolic resin, acrylic resins, coumarone , indene resins, cyclic rubber and mixtures of such resins.

As additives, the conventional thixotropic agents and thickening agents may be mentioned, for example bentonites, and / or silicic acid, gelling agents, such as aluminum chelate (= polymeric organic aluminum complex, dissolved in Dibutylphthahalat and mineral oil), wetting agents such as soya lecithin, fatty acid ester or Polyhydroxysterinsäure; Desiccants, such as cobalt and manganese compounds and lubricants, such as customary for offset inks waxes.

As liquid components of the ink may be mentioned vegetable oils and derived polyesters (alkyds), ​​for example based on linseed oil, soybean oil, sunflower oil, corn oil, grapeseed oil, safflower oil, tall oil, cottonseed oil, castor oil, tung oil, oiticica oil, perilla oil, and mineral and organic solvents, such as aliphatic and / or aromatic hydrocarbons having a boiling range between 150 and 400 ° C, for example, printing inks oil (= mainly paraffinic hydrocarbon mixture of 67% paraffins, 25% naphthenes and 8% aromatics with a boiling range 260-290 ° C eg Mihagan 26/29 B), as well as plasticizers, for example esters of adipic acid and citric acid, such as dinonyl adipate, isotridecyl alcohol and, optionally, antioxidants (for example 2,6-di-tert-butylcresol).

The liquid and solid components are combined in the manner customary for the printing ink proportions in a mixer and is processed directly to the offset printing ink or to concentrate. The mixers are suitable continuous or batch mixers, for example, with an output of about 60 kW / m³ operate. Suitable mixers are, for example Doppelwellendissolver, Laboratory Blender (from the company. Waring Commercial) etc.

It is important that sufficient mechanical energy is introduced. The process may be assisted by additional introduction of heat. In certain cases, it may also be necessary to dissipate the heat generated during the introduction of mechanical energy by suitable cooling.

A continuous mixer may be sectionally heated and cooled so expediently, while a non continuous mixer can have both heating and cooling.

The process may be carried out under air. In certain cases it may also be advantageous to work under an inert gas atmosphere so as to prevent air inclusions. Next, it may be in certain cases be advantageous to remove gas inclusions contained by applying a vacuum. but it is also possible to vent the product by subsequent passage through a three-roll mill.

The hard resins, coloring pigments and solid excipients are entered in powder form or as granules. The energy that is required for the comminution of the granules, must then of course be additionally introduced.

For certain reasons, which are not due to the process, there is often the demand, certain components such as color pigments or surcharges to bring in the form of pastes. This procedure is described also possible without disadvantage.

In particular, very temperature sensitive recipe ingredients, it may be advantageous to mix these ingredients, for example in paste form after cooling the batch below the critical temperature.

The inventive method allows an astonishing variability. For example, can be added the desiccant and miteingemischt in the production of offset inks in the first step. According to circumstances, the user the desiccant can also be added to the finished product. It is the same with other recipe ingredients. So it is possible. to prepare a printing ink concentrate and to dilute this later, a procedure example, can provide certain logistical advantages.

The parts and percentages mentioned in the Examples and Comparative Examples, unless otherwise indicated, parts by weight and percentages by weight.

example 1

In a laboratory mixer (manufacturer: Waring) are from about 52 parts of a mixture:<dl id="dl0001" compact="compact"><dt>29.9 parts</dt><dd>Printing ink oil (boiling range 260 ° to 290 ° C)</dd><dt>11,77Teilen</dt><dd>linseed oil</dd><dt>4.9 parts</dt><dd>castor oil and</dd><dt>3.6 parts</dt><dd>a mixture of<ul><li>20% Ditertiärbutylkresol</li><li>10% dinonyl</li></ul> and 70% Printing ink oil (boiling range 260 ° C to 290 ° C)</dd><dt>0.3 parts</dt><dd>isotridecylalcohol</dd><dt>1.5 parts</dt><dd>long oil linseed oil and</dd><dt>0.03 parts</dt><dd>aluminum chelate</dd></dl> 48.0 parts of a in a laboratory mill (manufacturer: Ika) pre-shredded mixture of:<dl id="dl0002" compact="compact"><dt>30.8 parts</dt><dd>rosin phenolic resin</dd><dt>and 16.7 parts</dt><dd>Pigment Red 57 and</dd><dt>0.5 parts</dt><dd>PTFE wax</dd></dl> and stirred for 5 minutes. The temperature of the batch increases during the mixing process at 123 ° C.

By stirring of 2% and 4% isotridecylalcohol inks oil the desired rheology is adjusted. Then a passage via a three-roll mill.

Comparative example

A mixture of<dl id="dl0003" compact="compact"><dt>16.7 parts</dt><dd>Pigment Red 57,</dd><dt>0.5 parts</dt><dd>PTFE wax and</dd><dt>2.9 parts</dt><dd>a mixture of<ul><li>20% Ditertiärbutylkresol</li><li>10% dinonyl</li></ul> and 70% Printing ink oil (boiling range 260 ° C to 290 ° C)</dd><dt>3.5 parts</dt><dd>linseed oil</dd><dt>2.0 parts</dt><dd>Printing ink oil (boiling range 260 ° C to 290 ° C)</dd><dt>4.9 parts</dt><dd>castor oil</dd><dt>62.2 parts</dt><dd>A binder</dd><dt>7.3 parts</dt><dd>binder B</dd></dl> is pre-dispersed using a dissolver. After further dispersion in a stirred ball mill is carried out by stirring in isotridecylalcohol and ink oil (eg Mihagan 26/29 B) an adjustment of the rheology to the values ​​of Example 1. Finally, again takes place through a triple-roll mill.

Binder A was prepared by heating for two hours with stirring to 180 ° C a mixture of<dl id="dl0004" compact="compact"><dt>38.2 parts</dt><dd>Kolophoniummodifiziertem phenolic resin</dd><dt>in 15.2 parts</dt><dd>linseed oil</dd><dt>13.6 parts</dt><dd>Printing ink oil (boiling range 260 ° C to 290 ° C) and</dd><dt>0.3 parts</dt><dd>a mixture of<ul><li>20% Ditertiärbutylkresol</li><li>10% dinonyl</li></ul> and 70% Printing ink oil (boiling range 260 ° C to 290 ° C) and</dd><dt>20.0 parts</dt><dd>long oil linseed.</dd></dl>

After the addition of<dl id="dl0005" compact="compact"><dt>2.3 parts</dt><dd>Printing ink oil (boiling range 260 ° C to 290 ° C) and</dd><dt>0.4 parts</dt><dd>aluminum chelate</dd></dl> the temperature for another 30 min. maintained at 180 ° C. After the addition of<dl id="dl0006" compact="compact"><dt>10.0 parts</dt><dd>linseed oil</dd></dl> is filtered and cooled.

Binder B was prepared by heating for two hours at 190 ° C and stirring of a mixture of<dl id="dl0007" compact="compact"><dt>44.8 parts</dt><dd>kolophoniummodifiziertem phenolic resin in</dd><dt>10.7 parts</dt><dd>linseed oil</dd><dt>33.0 parts</dt><dd>Printing ink oil (boiling range 260 ° C to 290 ° C)</dd><dt>0.5 parts</dt><dd>Isotridecyl and 1.0 parts of a mixture of<ul><li>20% Ditertiärbutylkresol</li><li>10% dinonyl</li></ul> and 70% Printing ink oil (boiling range 260 ° C to 290 ° C)</dd></dl>

After the addition of<dl id="dl0008" compact="compact"><dt>10.0 parts</dt><dd>Printing ink oil (boiling range 260 ° C bis290 ° C)</dd></dl> was filtered and cooled.

example 2

Determination of Bronciereffekts (instrument: Optronic Colour flash 45; D65 / 2 °)

The preparation method according to the invention surprisingly leads also to a reduction of the so-called Bronciereffektes (hue change depending on the incident light).

This disturbing effect as is in semi-opaque ruby ​​toners, such as Litholrubin D 4560 DD (BASF) or Irgalithrubin LPBC (Ciba-Geigy) clearly. After coating with dispersion varnish (or lamination) this optical effect disappears completely.

Test colors of the same composition, which are even prepared conventionally and the other according to the invention were printed on coated paper and in half coated with emulsion paint. Since this property is visible especially on black, a black surface was chosen. Thereafter, the color difference of the respective pressure is determined with and without varnish.

The larger the color difference Δ E is, the stronger is the Bronciereffekt of unpainted pressure.

The 17% strength with Litholrubin pigmented colors show as long as they were prepared by the novel process, lower by 28% Bronciereffekt than corresponding conventionally produced colors.