Lithographic ink

Cobalt(II) sulfate is used in storage batteries and electroplating baths for cobalt. It also is used as a dryer for lithographic inks in pigments for decorating porcelains in ceramics, glazes and enamels to protect from discoloring and as a additive to soils. 

Lithographic inks with good ink properties—tack, misting, reactivity, and printability... 

Use Weighting mud in oil-drilling, paper coatings, paints, filler and delustrant for textiles, rubber, plastics and lithograph inks, base for lake colors, X-ray photography, opaque medium for gastrointestinal radiography, in battery plate expanders. 

Use Paint pigment, lithographic inks, wallpaper (pigment), artists color. 

An overview of the lithographic process is presented with particular emphasis on the role that surface and colloid chemistry plays. Recent research has shown the importance of these chemistries in fountain solution, ink and plate interactions and the effect of these interactions on the dynamic behavior of the lithographic ink on press. Data on the rheological behavior of preformed fountain solution/ink emulsions is presented along with an evaluation of prints made with the inks on an actual press run. The importance of pre-testing the emulsification behavior of printing inks in predicting their printability is demonstrated. 

In order for a lithographic ink to move smoothly and uniformly through the press to the substrate, it is essential that the ink be able to absorb a reasonable quantity of the fountain solution being used as emulsified droplets. Many authors have observed this fact (Banks, (1), Surland (15,, MacPhee (18)) and... 

While it is evident that the rheology of lithographic inks has a profound effect on printability and press performance, most of the literature records only the rheology of the dry ink. 

In this investigation, a set of six experimental heatset lithographic inks were subjected to a variety of rheological measurements both as a dry ink, as well as after being emulsified with a commercial fountain solution. Determinations of apparent viscosity at 2500 secs l and yield stress at 2.5 secs l were made 25°C from 5 point shear rate/stress curves, and inkometer tacks at 1200 RPM/90°F were also measured. 

The shape of the emulsification rate curves is related to press performance of a lithographic ink. 

Analyses have repeatedly shown that 15% or more water is found in lithographic inks during or after normal printing. 

Figure 11. The effect of altering time between the application of water to the surface of a coated board and overprinting with a lithographic ink. (Reproduced, with permission, from Ref. 31. Copyright, Marcel Dekker, Inc.)...

Figure 18. Effect of extractive pH of paper on drying time of a lithographic ink (in a 75% RH atmosphere) (20).

Tack forces generated during ink film splitting are not well defined or easily measured with existing instrumentation. However, it is suggested that ink tack is related to ink elasticity, or more fundamentally, to molecular mobility of stiff chain polymer additives to lithographic inks. 

Establishments primarily engaged in manufacturing printing ink, including gravure ink, screen process ink, and lithographic ink. 

Letterpress and lithographic inks can be formulated from these thermally-catalyzed vehicles. Their main advantage is that they can be cured with the present flame or hot-air dryers, to give carbon dioxide and water plus small amounts of alcohols and formaldehyde. Moreover, the properties of these inks films are very good, particularly their reds-tance to scuffing, abrasion, or scratchiig. In addition, they handle well on the press distribtion system or on the printing plate, and their shelf life is adequate (3-6 months). 

When the thermosetting overprint lacquer No. 1 (Table VII) was applied to aluminum foil and cured at 275 °F (135 °C) for 10 s, heat resistance of the coating was in excess of 500 F (260 C). The thermoplastic overprint lacquer No. 2, when dissolved in an alcohol-water blend, may be applied directly to the wet lithographic ink in order to improve gloss and permit the use of less expensive inks, eliminate starch sprays ordinarily used to prevent setoff, improve scuff resistance, and eliminate hydrocarbon effluents by replacing heat-set inks with oxidizing inks. 

USE Usual source of water-soluble cobalt since it is the most economical and it shows less tendency to deliquesc or dehydrate than the chloride Or nitrate. Used in storage batteries in Co-electroplating baths as drier for lithographic inks, varnishes in ceramics, enamels, glazes to prevent discoloring in Co pigments for decorating porcelain. 

OTHER COMMENTS used in the manufacture of cellophane and photographic papers useful as a filler for rubber, linoleum, textiles, plastics, and lithograph inks also used as a water-color pigment for colored paper and in wallpaper other uses include x-ray photography and as an opaque medium for gastrointestinal radiography. 

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