Printing Inks

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<p>Smart Formulating for Printing Inks</p> <p>ContentsEvonik Products 3 Flexographic and Gravure Printing Inks 8 Offset Printing Inks Screen Printing Inks and Varnishes Overprint Varnishes 17 20 24 In the Chemicals Business Area, Evonik Industries is among the worldwide leading companies in specialty chemicals. It has several teams evaluating and supporting products for printing inks and varnishes and are always in close dialogue with you, our valued customers. Evonik makes important contributions in many areas, such as TEGO VariPlus products, Carbon Black Pigments and silicas, waxes and additives for wetting, dispersing, surface control and defoaming, to help you solve problems quickly. Our brochure is designed to help you obtain an overview of the products Evonik offers for printing inks and varnishes. Its structure helps you focus on the requirements and problems of a specic printing ink system.</p> <p>Introduction</p> <p>2</p> <p>EVONIK PRODUCTS FLEXOGRAPHIC AND GRAVURE PRINTING INKS OFFSET PRINTING INKS SCREEN PRINTING INKS AND VARNISHES OVERPRINT VARNISHES</p> <p>Evonik ProductsResinsTEGO VariPlus products are used very widely and in great variety due to their different and mutually complementary properties. The manufacture of special resins with ketone, alcohol, acid and/or urethane groups is based on ketone-aldehyde chemistry. All products satisfy the requirements for labeling as environmentally compliant. Moreover, Evonik offers resins that are totally free of formaldehyde. All resins are non-saponiable, neutral and hard. Because of their high softening points, TEGO VariPlus products do not form lms. Low in molecular weight and almost colorless, they are lightfast and exhibit good compatibility with other binders. Due to their well-balanced polarity they are soluble in a wide range of solvents. A waterborne dispersion with outstanding properties and stability, free of organic solvents, is also available. TEGO VariPlus products can be used as grinding resins or as auxiliary resins in the let-down stage. They improve many of the properties of printing inks and overprint varnishes such as color strength and shade, transparency, gloss, hardness, adhesion, blocking resistance and resistance to solvents or chemicals. They also increase solids content or decrease drying time. Evonik offers different grades of TEGO VariPlus products for use in solventborne, waterborne or radiation-curing printing inks. Products of the TEGO AddBond series are special tailor-made polyesters for improving the adhesion of printing inks to metallic and plastic substrates and the intercoat adhesion of multicoat formulations. Gloss and exibility are demonstrably improved and, moreover, TEGO AddBond products are resistant to light, weathering and saponication. There is a wide portfolio of products for solventborne, waterborne and radiation-curing formulations. TEGO AddBond products are widely used not only in printing inks but also in can coatings, coil coatings, automotive-OEM nishes, industrial coatings, and lacquers for corrosion protection.</p> <p>Acrylic resinsMethacrylic resins have proved their suitability for many years as binders for formulating printing inks. They are noted in particular for their universal solubility, excellent chemical resistance, lightfastness and good compatibility with other coatings raw materials and pigments. They show good adhesion to various substrates such as plastics, paper, textiles and metal. DEGALAN has shown itself to be especially suitable for printing packaging materials.</p> <p>Carbon Black Pigments and Silicas/SilicatesUsing various technologies, Evonik produces ne-particle Carbon Black Pigments and silicas, which perform a variety of functions in printing inks and printing auxiliaries. Whereas the Carbon Black Pigments improve readability of printed matter, the synthetic silicas and silicates promote properties such as owability, ink/water balance, anti-misting and especially matting. Although the trend in recent years has been towards increased use of colored printing inks, approx. 150 000 t/a of Carbon Black Pigments are used worldwide in the manufacture of printing inks. It is constructive to consider why Carbon Black Pigments are so important. Their high efciency in combination with excellent fastness at relatively low cost benets printing ink manufacturers. Evonik can choose between three different process technologies (the furnace black, gas black and lamp black processes) and can thus offer Carbon Black Pigments with properties which can be tailor-made for different aspects of printing ink formulation. These products are supplied to printing ink manufacturers under the trade names PRINTEX, HIBLACK, NEROX and SPECIAL BLACK.3</p> <p>The most important features are the size and structure of the primary pigment particles and their agglomerates. They dene the coloristic properties such as undertone, optical density, gloss and also the rheological effect of the Carbon Black Pigments and their dispersibility in the binders.</p> <p>Irrespective of the print technology, simple relationships can be dened between the properties of the printing ink and the primary particle size and structure. For lm thicknesses less than 10 m, typical for printing inks, the following relationships are true: Synthetic silicas and silicates comprise the second group of neparticled products manufactured by Evonik. Products of major interest for the printing inks sector are manufactured not only by the AEROSIL technology developed by Evonik, but also by the Carbon Black Pigments precipitation process. Both technologies lead to ne-sized, amorphous materials with physico-chemical properties which can The lower the primary particle size, the higher the optical be altered by adjusting of production parameters. density of the ink lm. AEROSIL, SIPERNAT and ACEMATT grades have been wellThe lower the primary particle size, the more brownish the known for many years as products for optimizing the features of undertone of the print. printing inks, overprint varnishes, and printing auxiliaries. These The lower the primary particle size, the higher the increase in products are not only advantageous for the production of printing viscosity of the printing ink. inks and for their storage and printability but also for the nal The more structured the Carbon Black Pigment, the higher the print product. increase in viscosity of the printing ink.</p> <p>technology already possess a high proportion of volatile components which indicates a high level of oxidized surface groups. Oxidized groups on the surface of a furnace black are the result of a special after-treatment process. Such products are also part of Evoniks portfolio of carbon blacks under the names NEROX and SPECIAL BLACK. The surface chemistry is important for the wetting of the carbon black by the binder so that this aspect also inuences properties such as rheology and gloss of the printing ink.</p> <p> The more structured the Carbon Black Pigment, the better the The more structured the Carbon Black Pigment, the better thehold-out but also the lower the gloss of the ink lm. dispersibility.</p> <p>Another important property of the Carbon Black Pigment is the level of oxidation of the pigment surface, which depends on the production process. Products manufactured by the Evonik gas black</p> <p>AEROSIL fumed silicas are characterized by their very small primary particles and high specic surface area. These are not isolated primary particles but aggregates and agglomerates that dene the typical application properties of AEROSIL products. The AEROSIL particles are hydrophilic due to their silanol groups, but for certain AEROSIL grades these silanol groups are modied by chemical reactions, resulting in hydrophobic particles which are characterized by a very low moisture uptake.</p> <p>4</p> <p>EVONIK PRODUCTS FLEXOGRAPHIC AND GRAVURE PRINTING INKS OFFSET PRINTING INKS SCREEN PRINTING INKS AND VARNISHES OVERPRINT VARNISHES</p> <p>With the ACEMATT products Evonik offers a complete portfolio of silica-based matting agents whose prole of properties, such as particle size, particle size distribution, and surface modication, is ideal for the matting of printing inks. The desired matt effect of the printing ink or overprint varnish can be achieved by suitable choice of product. As can be seen from this short introduction to the properties of carbon black and synthetic silica, interaction of the various features has a marked effect on the printing ink. Furthermore the choice of the right Carbon Black Pigment or silica is largely determined by the print technology and its special demands on printing ink properties such as rheology, ink/water balance, matting or optical density.</p> <p>The Evonik Ziegler polymerization of ethylene synthesizes both HDPE waxes and LLDPE waxes with a wide range of density (0.91 0.96 g/cm3) and molecular weight (1000 4000 Dalton). The well balanced ratio of amorphous and crystalline components of Evonik VESTOWAX A-grades (PE-waxes) combined with a high molecular weight, leads to outstanding surface protection (rub- and scratch-resistance), high pigment loading (e. g. as a carrier for pigment concentrates) and high heat resistance in different applications. Enhancement of both product groups is accomplished by oxidation, saponication, esterication and compounding and leads to an extensive range of grades. In combination with the different supply forms (from pellets to micro powders) these offer solutions to a multitude of applicational problems. Micronized waxes are especially suitable for improving the surface properties of printing ink formulations. They can easily be incorporated directly by cold dispersion or by cold grinding. It is unnecessary to heat the wax and solvent and the production process is thus simple and fast. Micronized VESTOWAX grades are available with either spherical (sprayed) or irregular (ground) particle shape. Advantages of spherical particles are good slip, high rub resistance and high gloss retention. Irregular particles are used for good wetting and dispersion properties, minimal agglomeration and high matting effect. Furthermore VESTOWAX grades in pellet form can be used for the production of solventborne dispersions and pastes as well as for waterborne dispersions (emulsions). These dispersions, pastes and emulsions are produced for easy incorporation of waxes into printing ink formulations.</p> <p>WaxesThe VESTOWAX range of synthetic waxes consists of two different product groups: Fischer-Tropsch waxes and Polyethylene waxes. Crude Fischer-Tropsch waxes are manufactured by polymerizing products obtained from natural gas into waxes (producer Shell, Malaysia). Physical and chemical modication of Fischer-Tropsch waxes at the Evonik wax plant leads to a variety of modied waxes. Characteristic of Fischer-Tropsch waxes is the combination of low molecular weight, narrow molecular weight distribution, low viscosity, straight chain structure and high drop point which results in good heat resistance, low surface tension and high release and slip effects in many different applications.</p> <p>5</p> <p>Tego AdditivesEvoniks comprehensive Tego range of surface-active additives for printing inks and coatings improves the production, application and nal properties of the inks and varnishes. TEGO Dispers pigment wetting and dispersing additives speedup the wetting of the pigment particles and adsorb on the pigment surface. They stabilize the pigment and reduce the viscosity of the grind resulting in: tension to ensure proper wetting. This can be achieved by the use of organo-modied polysiloxanes with a relatively short siloxane backbone (TEGO Wet 2xx series). For optimum dynamic performance in waterborne inks combined with some degassing activity, a range of silicone-free surfactants is available (TEGO Wet 5xx series). Combining the principles of Gemini surfactants and siloxane chemistry it becomes possible to create powerful surface tension reducers with distinct defoaming properties (TEGO Twin 40xx series). In several applications, combinations of a silicone-free with a siloxane-based substrate wetting additive have proved benecial.</p> <p> shorter grinding times because of faster color development higher color strength higher transparency or lower hiding power higher gloss improved rheology and rheological stability possibility of higher pigment loading.</p> <p>TEGO Glide and TEGO Rad Surface Control Additives are TEGO Dispers products are available for waterborne, solventsiloxane-based. They reduce surface tension, promote wetting and borne and radiation-curing printing inks. They are polymeric ow and create a slip effect on top of the ink or varnish. They products based on different technologies; all of them are APE and also improve the scratch resistance and the anti-blocking properties silicone-free. The optimal choice of wetting and dispersing additive of the ink or varnish without interfering with gloss. depends on the type of pigment and the overall formulation. During drying or curing of the ink, slip additives migrate to the TEGO Wet and TEGO Twin act primarily as surface tension surface where they form a thin, invisible liquid lm that acts as reducers and improve the wetting of the ink or varnish on various an effective lubricant on the dry lm. Special TEGO Glide substrates. Low energy substrates (e. g. polyolenes) and conadditives are required if the ink must remain overprintable or taminated substrates require a very strong reduction in surface bondable.</p> <p>6</p> <p>EVONIK PRODUCTS FLEXOGRAPHIC AND GRAVURE PRINTING INKS OFFSET PRINTING INKS SCREEN PRINTING INKS AND VARNISHES OVERPRINT VARNISHES</p> <p>The cross-linkable TEGO Rad products which contain reactive acrylate groups and react by free-radical curing have been specially developed for radiation-curing formulations. Their use minimizes extractables, creates longer lasting effects and very strong release properties. TEGO Foamex and TEGO Airex Defoamers and Deaerators make use of surface activity combined with controlled incompatibility. They are efcient at preventing the stabilization of entrained air, and break down and release foam once it has been generated. They are very suitable for the higher printing speeds increasingly encountered today and have been an indispensable formulation component especially in waterborne and radiationcuring inks and varnishes for many years. TEGO Foamex and</p> <p>TEGO Airex are available as siloxane-based and siloxane-free products. Maximum efciency is obtained by the use of siloxanebased products. For waterborne inks, different kinds of products are available: concentrates mainly for the grinding stage, solutions for universal use and emulsions for easy incorporation at the letdown stage or into clears. Tego additives are based on a wide range of technologies including polyacrylate-, polyurethane-, fatty-acid derivative- and poletherchemistries. Siloxane chemistry is used whenever very high surface activity is required. Hardly any T...</p>

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