Pigments speciality

Column and paper chromatography separation of plant pigments Special Equipment... 

R. Lapasin, G. Torriano, S. Volpe nd. Vernice 29 (1975) no. 4, 2-19. (Thick-film paints based on chlorinated rubber and inert pigments - special aspects of anticorrosive properties and the film-forming process)... 

Dow Coming Z-6070 Silane pigment, special effect paints... 

Baiiace B-30 Baiiace B-34 pigment, specially decorative coalings... 

Paints contain resins, such as polyester, epoxies, or urethanes. They are blended with pigments, special waxes, and other ingredients to achieve unique properties. Truely... all prepaints are not created equally. Comparable prepainted and postpainted samples subjected to the same humidity and corrosion tests favor the prepaint in its ability to resist corrosion, especially on cut edges. That fact surprises most manufacturers. 

Rigid PVC Heat stability up to 200°C Good light stability Easy dispersion important Cadmium Yellow toners Azo condensation Polycyclics Lead pigments Phthalocyanine Isoindolinones Selected Bis-arylamides Dioxazin Lead pigments Special monoazos... 

LDPE Heat stability normally up to 240°C Moderate light stability for many applications Easy dispersion important Red and yellow toners Selected Bis-aryiamides Isoindolinone Azo condensation Phthalocyanine Green Phthalocyanine Blue Cadmium pigments Iron oxides Lead pigments Ultramarine Blue Vat pigments Special monoazos... 

Crystal PS Good light stability Processing temperatures up to 240°C Red and yellow toners Polycyclics Azo condensation Isoindolinone Metal complex Phthalocyanine Blue Phthalocyanine Green Selected dyes Ultramarine Blue Cadmium pigments Lead pigments Special monoazos... 

Pigments commonly used are titanium dioxide and extender pigments. Special lead-containing pigments e.g. silicates are used as anticorrosive agents. Lead also catalyzes the curing reaction, however the trend nowadays is eliminate lead from electrocoat. Solvent content is low (typically less than 2 % based on total volume). The solids content is ca. 20 %. 

Green coloration, present in many vegetable oils, poses a particular problem in oil extracted from immature or damaged soybeans. Chlorophyll is the compound responsible for this defect. StmcturaHy, chlorophyll is composed of a porphyrin ring system, in which magnesium is the central metal atom, and a phytol side chain which imparts a hydrophobic character to the stmcture. Conventional bleaching clays are not as effective for removal of chlorophylls as for red pigments, and specialized acid-activated adsorbents or carbon are required. 

Technological History (26,54—61). As a first approach, there are three groups of components supports, paint media, and pigments. The support is the substrate upon which the paint layers are laid down. This can be a specially prepared area on a wall for a wall painting, a wooden panel as in a panel painting, or a fabric in canvas paintings. Paper is a prevalent support in Oriental painting. Other supports are encountered less frequently, eg, metal panels such as copper sheet. 

Poly(vinyl fluoride) is available from Du Pont both as a resia and as transparent and pigmented films under the trademark Tedlar PVF film. Films are available ia nonoriented and oriented grade ia several tensile modifications and thicknesses, with either adherable or nonadherable release-grade surfaces. The 1992 prices ranged from 30 to 70/kg, vs 24 to 62/kg ia 1988. Prices for specially tailored films were significantly higher. 

Preformed Two-Piece Metal Containers. Ink vehicles for letterset printing of two-piece aluminum or steel containers are mainly based on special polyester vehicles used in conjunction with melamine cross-linkers. Short cycle ovens which dry inks in 1—5 seconds are now used and operate at temperatures as high as 350 °C. The rheology of these inks must be adjusted to the unique geometry of the press. Desired rheological properties are achieved by the use of additives as weU as extender pigments. 

Recent pigment technology has yielded a wide range of products which ate much mote specialized for individual end use applications. New polymers have been combined with improved dyestuffs to yield fluorescent pigments with better performance properties and economics, and more desirable environmental characteristics. 

To produce the mtile titanium dioxide pigment, hydrolysis of the mother Hquor has to be carried out in the presence of a specially prepared hydrosol as a seeding agent. This hydrosol is made by the neutralization of a portion of the mother Hquor in the presence of hydrochloric or some other monohydric acid. Because of the large amount of the hydrosol that must be added to the mixture (about 6% concentration), the hydrolysis reaction takes only about 1 hr. 

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