Titanium dioxide pigment dispersion

Titanium dioxide pigment coated with pentaerythritol, trimethylolpropane, or trim ethyl ol eth an e exhibits improved dispersion characteristics when used in paint or plastics formulations. The polyol is generally added at levels of 0.1—0.5% (96). 

Wavelength dispersive x-ray fluorescence spectrometric (xrf) methods using the titanium line at 0.2570 nm may be employed for the determination of significant levels of titanium only by carefiil matrix-matching. However, xrf methods can also be used for semiquantitative determination of titanium in a variety of products, eg, plastics. Xrf is also widely used for the determination of minor components, such as those present in the surface coating, in titanium dioxide pigments. 

A number of thermal stability tests arc available, some of which have developed into national (DIN) or international industrial standards (ISO). Pigments in thermoplastic systems, for instance, are studied under heat extrusion conditions [110]. The colorant to be tested, possibly together with titanium dioxide, is dispersed in the thermoplastic, using a mixer and a granulating extruder (Sec. 1.8.3). The pigmented test pellets are then fed into a screw extruder which ejects a standardized test specimen with defined dimensions [111]. Starting at the lowest possible temperature level, the extrusion temperature is increased by intervals of 10 or 20°C between samples. 

Titanium dioxide pigments are also used as UV absorbers in sunscreen products, soaps, cosmetic powders, creams, toothpaste, cigar wrappers, and in the cosmetics industry. Their most important properties are their lack of toxicity, compatibility with skin and mucous membranes, and good dispersibility in organic and inorganic solutions and binders. 

Dispersant demand and selection for titanium dioxide pigments. TDIOO. Millenium Inorganic Chemicals. 

One year before the end of this period (in 1939), the first chalk-resistant pure titanium dioxide pigment was produced by the National Lead Co. Although never described as such at the time, this was also the first commercial rutile titanium dioxide, which accounted for some of its improved chalk resistance. Since the rutile structure had been attained by overcalcination, its overly large particle size and poor dispersibility prevented it from attaining the increased hiding power that should have accompanied its conversion to rutile, and the pigment was manufactured only until the end of World War II to satisfy the demand of the U.S. Navy for a durable titanium dioxide. 

The most useful attempt to describe the stability of concentrated systems has been made by Levine -, who concluded that electric double-layer effects are unable to provide the necessary energy barrier for dispersions in hydrocarbon media. A similar conclusion was reached from experimental observations of the stability/opacity of dispersions of titanium-dioxide pigments in alkyd resin solutions. ... 

Figure 6. Dispersion quality of titanium dioxide pigment concentrates as measured in LLDPE blown film. Letdown levels have been adjusted to give...

Chem. Descrip. Aq. compd. based on titanium dioxide and dispersants Uses Pigment for paste coatings, foam coatings Properties Wh. si. vise, paste Tubicoat Weiss FX [CHT R. Beitlich GmbH]... 

Tests on acrylic/styrene dispersions having varying minimum film forming temperatures demonstrate that when a suitable binder is used, solvent-free paints can be formulated, which exhibit weathering behaviour comparable to that of conventional solvent-based paints. Rutile titanium dioxide pigments are shown to have a greater influence on weathering resistance than the binder. 6 refs. 

C.G. Waterfield and J. Peacock, The Application of Contact Microradiography to the Study of Dispersion of Titanium Dioxide Pigment in Solids, Technical Service Report No.D8753GC, BTP Tioxide Ltd., Stockton-on-Tees, UK, (undated). 

The stability of dispersion was determined by a sedimentation method. The suspensions were prepared by dispersing titanium dioxide pigments by a paint shaker with glass beads in the surfactant solutions. The solution was then poured into a sedimentation test tube. 

Kemlra 470 is a rutile titanium dioxide pigment designed to meet the needs of the most demanding plastics applications. It has the same brightness and tone properties as standard Kemira 460 but is end-treated to impart hydrophobic properties. This results in outstanding dispersibility and significantly improved high temperature performance. Kemira 470 rutile titanium dioxide meets the requirements of specification ASTM D 476-84 (1989), Type II III. 

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