Opaque inks

Opaque ink n. An ink that does not allow the light to pass through it and has good... 

Monodisperse pol mier particles can be s mthesized. Monodisperse pol5nner particles provide an opaque ink with improved color brilliancy (5). 

White Pigments. Opaque white pigments commonly used in inks, in order of decreasing opacity, ate titanium dioxide and zinc oxide. TiO is by fat the most popular white pigment. Mixtures of whites ate often made with the various colored pigments to add opacity or to make pastel colors. 

Unlike most diaryhde yeUows, YeUow 83, a reddish yeUow, possesses very good lightfastness particulady ia its opaque form and consequentiy is used ia plastics and paints ia addition to inks. 

Titanium dioxide (E171, Cl white 6) is a white, opaque mineral occurring naturally in three main forms rutile, anatase, and brookite. More than 4 million tons of titanium dioxide are produced per year and it is widely used for industrial applications (paints, inks, plastics, textiles) and in small amounts as a food colorant. ° "° Production and properties — Titanium oxide is mainly produced from ilmenite, a titaniferous ore (FeTiOj). Rutile and anatase are relatively pure titanium dioxide (Ti02) forms. Titanium oxide pigment is produced via chloride or sulfate processes via the treatment of the titanium oxide ore with chlorine gas or sulfuric acid, followed by a series of purification steps. High-purity anatase is preferred for utilization in the food industry. It may be coated with small amounts of alumina or silica to improve technological properties. 

A number of diarylide yellow pigments are also available in the form of very opaque products with small specific surface areas. These are used to an appreciable extent in Chrome Yellow free paints, in packaging printing inks, and other media. Fastness to light and weather are much improved in opaque varieties, compared to the corresponding transparent types their rheological characteristics are superior. Opaque pigments are not resinated. 

The pigment affords a reddish shade of brown. The commercially available types feature a high specific surface area of approximately 80 m2/g and are therefore highly transparent. P.Br.25 is somewhat less fast to some solvents than other pigments of the same class. It is used in paints, plastics, and printing inks and is in these areas in direct competition with the coloristically closely related but somewhat yellower and more opaque P.Br.23. 

P.Y.139 is a reddish yellow pigment, used in plastics, paints, and printing inks. The commercial types exhibit a wide variety of particle size distributions and accordingly demonstrate very different coloristic properties, which is especially true for the hiding power. The opaque version is considerably redder. Incorporated in a paint, it is less viscous, which makes it possible to increase the pigment concentration without affecting the gloss of the product. 

In printing inks P.Y.173 it is a very green shade opaque yellow with excellent light, weather and solvent fastness properties, but low color strength. It is recommended for paste and liquid inks where high fastness properties are required as well as for water based decorative inks. 

Despite of a specific surface area of 57 m2/g the commercially available grade affords opaque prints. Prints of an ink with 7,5% P.Y.201 equal step 3-4 on the Blue Scale for lightfastness. 

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. 

Zinc oxide occurs in nature as mineral zincite. It is the most important zinc compound and has numerous industrial applications. Zinc oxide is the pigment in white paints. It is used to make enamels, white printing inks, white glue, opaque glasses, rubber products and floor tiles. It is used in cosmetics, soaps, pharmaceuticals, dental cements, storage batteries, electrical equipment, and piezoelectric devices. Other applications are as a flame retardant, as a UV absorber in plastics, and a reagent in analytical chemistry. A major application of zinc oxide is in the preparation of most zinc salts. In medicine, the compound is used as an antiseptic, an astringent and a topical protectant. 

Zinc oxide has a wide range of uses apart from its use as an artist s pigment where it provides a more translucent white than flake white or titanium white. It is used in cosmetics, driers, quick-setting cements with syrupy phosphoric acid or zinc chloride in dental cement in the manufacture of opaque glass, enamels, car tyres, white glue, matches, white printing inks and porcelain. The photophysics of zinc oxide has been reviewed.1468 ... 

Unlike most diarylide yellows, Yellow 83, a reddish yellow, possesses very good lightfastness particulady in its opaque form and consequendy is used in plastics and paints in addition to inks. 

Behaviour towards Sulphuric Acid.—This test, which gives an indication of the nature of the colouring matter of the ink, is carried out as follows A small quantity of the ink is diluted with water to give a non-opaque solution, dilute sulphuric acid being then added and the changes in tint observed. 

Print the figure on clean, opaque, white paper, using a fresh ink or toner cartridge. Do not use a dot matrix printer. Set the laser or inkjet printer to a resolution of at least 600 ppi. 

---