Water based ink

The environmental concerns associated with the use of toluene, a toxic and flammable aromatic hydrocarbon, as a gravure ink solvent must be addressed. Whereas ink manufacturers are working on the development of water-based inks, the slow drying times and poor printing quaUties of the prototype products have impeded commercia1i2ation. Furthermore, the high cost of these materials is seen as a barrier to their introduction. 

Inks for continuous ink-jet printers typically comprise dyes dissolved in water or solvent having salts added to make the ink conductive for electrostatic charging. Whenever waterproof printing is required, low boiling solvent inks ate used. For printers that ate used in office environments, water is used as the ink solvent. Using water-based inks, humectants may be added to inhibit drying of ink in the sump and surfactants ate added to wet the printing surface. 

The monoisobutyrate ester of TMPD, Texanol, or Filmer IBT, formally an isobutyraldehyde trimer, is prepared in a single step from isobutyraldehyde or, alternatively, by the esterification of TMPD with isobutyric acid. This monoester is most commonly employed as a coalescing agent for latex-based paints and water-based ink formulations. 

Nippon Kayaku. New Phthalocyanine Compounds Useful in Water-Based Inks are Prepared by Reacting Aminophthalocyanine Compounds with Methacrylic or Acrylic Acid. World Patent Application, 200064901 A, 27 April, 1999. 

Another benefit of the fluorinated layer is its excellent adhesion properties. Printing (including water-based inks) and labels will normally adhere tenanciously to a fluorinated layer. In some cases it is even possible to fluorinate printed containers without discoloration ofthe printing. In these cases the printing will be far more insoluble to a large spectrum of solvents and will then only be removed with difficulty. 

Carboxylate-based brine solution, 9 33 Carboxylated acrylic polymers, in water-based inks, 14 326 Carboxylation, 9 282 Carboxyl cure sites, in ethylene-acrylic elastomers, 10 698... 

Water-based inks, 14 326 Water-based muds, 9 3-5 Water-based writing inks, 14 328 Water-borne adhesives, 25 475 Waterborne alkyds, 2 156-158 Waterborne automotive coatings, 10 448 Waterborne can coating system, 10 445-446... 

It promotes adhesion of intaglio inks to the polypropylene surface. An acrylic based primer is a good choice because of its ability to effectively bond water-based inks. Dry powder form of acrylic primer is diluted with methyl ethyl ketone and xylene (each component is mixed in equal parts by weight). To create the opaque surface, 5wt% titanium dioxide pigment is added to the solution. 

In general, Ecoflex and Ecovio can be printed and welded on standard equipment for PE-LD. Both alcohol-based or water-based inks can be used after testing. Prior to printing, the material has to be corona-treated if the surface tension is below 38 dyn. In most cases printing of Ecoflex and Ecovio using alcohol-based inks does not require corona treatment. The drying temperatures should be kept below... 

In flexographic printing there has been a move away from solvent inks to the more environmentally friendly water-based inks. This has led to a renewed interest in the use of this technology. ... 

P. Laden (Ed.), Chemistry and Technology of Water Based Inks, Blackie Academic, London, 1997. 

Water-Based Inks. Approximately 50% of all flexographic inks use water as their primary solvent and diluent. They contain vehicles based on either acrylic emulsions, or hydrosols or an alkali-soluble rosin ester having a high acid number such as partially esterified fiimurated rosin and shellac. Carboxylated acrylic polymers, usually containing some styrene, have largely replaced natural resins because they provide better abrasion and water resistance. Ammonia or other volatile amines are used to solubilize these carboxylated resins and form resin salts. The volatile alkali evaporates from the ink film, rendering the printed matter water resistant. 

Bulk incorporation into water-based ink CoPC <3a 25 2 500 >78 Crouch et al. [19]... 

With respect to living polymerization of meth(acrylates), GTP is the only technique being used commercially. Block polymer dispersing agents for pigmented water based inks and for dispersing pigment in polymer resins are the products. These hi-tech uses can afford the additional cost to run GTP vs traditional polymerization procedures. For other uses lower cost methods are still needed. 

A major improvement in permanence of ink-jet prints in recent years has been due to tailoring pigment dispersions for both solvent and water based ink jet inks [18], These pigment containing inks are primarily used for outdoor applications. 

In addition to its use in PTT, 1,3-propanediol can replace traditional glycols in urethane-based polymer systems, improving thermal and hydrolytic stability. As a partial substitute for traditional glycols in polyester systems, 1,3-propanediol can improve coating flexibility without affecting other key properties. Other applications include engine coolants and water-based inks (33). 

Liquid thioxanthones, for example, 631 and 632, have been synthesized in order to improve formulation of photopolymerizable compositions <1998W09842697> and thioxanthones possessing either cationic 633 <1998W09853369> or anionic 634 <2000MI212> hydrophilic substituents have been prepared and successfully employed for curing water-based ink formulations. The mode of action of the latter ionic compounds appears to involve both the lowest excited triplet and singlet states . 

At present, the most important technical objective for the flexographic process is to reduce or eliminate the use of inks based on organic solvent. The research is directed mainly towards improving water-based inks but several reports on the use of UV-cured inks have been published. For applications in which no alternative to solvent-based inks is available at present the trend is towards eliminating hydrocarbon solvents. 

Generally inks for flexography are similar in composition to those for gravure but with an alcohol/ester solvent blend to reduce the extent of attack on rubber-covered rollers. Water-based inks also are being used successfully. 

The application of this form of printing, using PVC plastisols and water-based inks, is described later in this chapter. 

Today, the printing of vinyl wallcoverings by gravure and flexographic methods should present few difficulties the surface characteristics of the base material usually are of good standard but when using water-based inks attention may have to be paid to aspects such as surface tension and wettability. 

The technique is very versatile and adaptable. Plastisols may be applied overall or—by means of engraved screens—can be printed in selected areas, in weights that can be varied between 30 g m-2 and more than 500 g m-2. Suitable substrates include paper, other non-woven materials, glass-fibre webs, and textiles. Water-based inks can be employed as coatings or in printed designs. For relief effects, expandable aqueous polyacrylate dispersions offer an alternative to expandable plastisol inks. They are dried and then expanded at 120°C, a temperature much lower than is required for vinyls with a multi-station machine, a wide variety of products can be made. 

Thinner blades (e.g., 0.15 mm) can be used successfully with water-based inks but show a tendency to float when printing with plastisols. 

Printing inks, utilized in printing and packaging applications, are colored, liquid materials consisting of essentially two components the colorant, an insoluble solid or a dye, and the vehicle, a liquid in which the colorant is suspended or dissolved. Recent years have seen significant progress in water-based inks, but... 

Mitsubishi Chemical Corp. developed a water-based ink composed of photo-chromic-containing capsules and an aqueous polymer binder.46 The average particle size of the capsules containing photochromic spirooxazine and antioxidant was 20 pm. By using this ink composition, cotton clothes could be screen printed. The printed part showed coloration within 10 s when exposed to sunlight and exhibited good fatigue resistance. Furthermore, it bleached within 15 s in the dark, and this process was observed repeatedly. 

There are currently four main types of inkjet inks phase-change, solvent-based, water-based, and UV curable. Other types exist, but are less prevalent, such as oil-based and hquid toner (for electrostatic inkjet technology). Hybrid versions of the four main types also exist (e.g., water-based inks containing some amount of solvent). The various inkjet ink types will be discussed briefly in this chapter, and will be followed by detailed description in separate chapters (solvent-based, water-based, and UV cmable inks). 

Water-based or aqueous inks are prevalent on the desktop and enjoy the advantage of being relatively inexpensive and environmentally friendly, but penetration in industrial applications has been slow for a variety of reasons. Water-based inks tend to require porous or specially treated substrates or even lamination to impart durability and the ink tends not to adhere to non-porous substrates. Additionally, many piezoelectric industrial print heads are incompatible with water-based ink formulations, although this is changing in some part due to market demand for systems that can jet water-based biological or food contact fluids. 

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