Pigment metallic

Several methods of metallic image generation with the use of inkjet technology have been described (28). 

organometallic precursors dissolved in organic solvent with subsequent conversion of the precursor to metal at elevated temperatures of around 300°C can be used for the deposition of metal structures. A close to bulk conductivity of printed silver films has been achieved with such compositions (30,31). 

In order to reproduce metallic luster on printed matter, a printing ink with a pigment comprising a metal such as alutnimun, metal, silver or brass or an alloy thereof has been used (34). 

There exists a method of forming a thin metal film on a base material by using a noble metal colloid of gold or silver (34). Stable gold colloidal particles have a particle size of about 10-20 nm, and the color of a colloid dispersion is purple in this state. In this case, in order to obtain a thin film of gold, it is necessary to heat at 150 C or more. 

Further, it is also possible to stably disperse a gold colloid having a larger particle size by adding a protective colloid. However, in this case, no thin metal film is obtained imless treatment for decomposing and removing the protective colloid is conducted. For these reasons, in the method in which a metal colloid is used, after 

Fine particles of malleable metals in elemental form are also used as pigments in coatings for aesthetic as well as protective purposes. They are generally platelet-shaped particles, but some are spherical. 

---

COPPERALLOYS-WROUGHT COPPER AND V/ROUGHTCOppEP AT,TOYS] (Vol 7) -in metallic pigments [PIGA4ENTS - INORG iNIC] (Vol 19)... 

The only components in a coating powder which might cause the waste to be classified as hazardous are certain heavy-metal pigments sometimes used as colorants. Lead- (qv) and cadmium-based pigments (qv) are seldom used, however, and other potentially hazardous elements such as barium, nickel, and chromium are usually in the form of highly insoluble materials that seldom cause of the spent powder to be characterized as a hazardous waste (86). 

Fillers fibreglass, silicas, calcium carbonate, powdered metal pigments some may be absorbed potential primary irritant dust inhalation low toxicity... 

If a paint film is to prevent this reaction, it must be impervious to electrons, otherwise the cathodic reaction is merely transferred from the surface of the metal to the surface of the film. Organic polymer films do not contain free electrons, except in the special case of pigmentation with metallic pigments consequently it will be assumed that the conductivity of paint films is entirely ionic. In addition, the films must be impervious to either water or oxygen, so that they prevent either from reaching the surface of the metal. 

Sanding is carried out at this stage and, after clean-up, the final colour or top-coat is applied. There is some variation in the resin chemistry used. Alkyds crosslinked with melamine-formaldehyde are widely used for non-metallic pigmentation. Metallics are usually based on acrylics for better durability. The acrylic may be thermoset with melamine-formaldehyde or a thermoplastic lacquer (plasticised copolymer of methyl methacrylate). A thickness of about 50ftm is applied and stoved for 20 min at 130°C (lacquers receive a bake-sand-bake process for a smoother appearance). 

I.R. Wheeler, Metallic Pigments in Polymers, Rapra Technology Ltd, Shawbury (1999). 

Solvent dyes are used to colour the transparent paints used to exploit the special properties of metallic pigments, as mentioned earlier. Another use for solvent dyes is in the colouring of many plastic articles to supplement the colouring power of pigments, if the use of pigments alone in a particular application is found to have undesirable effects on the physical properties of the plastic. 

New York City, 2nd-6th May 1999, p.2854-8. 012 BANNING HEAVY METAL PIGMENTS IN MINNESOTA - THE NEXT ICEBURG ... 

Due to their high specific surface area, metallic pigments are pyrophoric, so that passivation is necessary. This can be achieved by slow, controlled oxidation of the particle surface [5.31],... 

Metallic pigments have a higher specific surface area (up to 60 m2/g) and a higher saturation magnetization than oxidic magnetic pigments. Their capacity for particle alignment corresponds to that of the oxides (see Section 5.1.1, Table 36). 

During the ball milling process, a lubricant is added to prevent cold fusion it also determines the wetting properties of the metallic pigment, i.e., leafing or nonleafing . 

Uses. Metallic pigments are used to produce metallic or chrome effects and also as functional pigments (e.g., for corrosion protection, as conductive paints, or for protection against electromagnetic radiation). 

Metallic Pigments, The leading metallic pigment is zinc dnst, which is used mostly in zinc-rich primers, where it acts as a passivating agent. Aluminum flake is used for the silvery metallic appearance that it imparts. 

A very important and large group of the artificial colours is that composed of definite metallic compounds (oxides, hydroxides, salts) or of mixtures of two or more compounds, or of carbon either alone or associated with other substances. Metallic pigments consist of powdered metals. The lakes, formed from organic colouring matters fixed on mineral substances—mostly metallic oxides—are usually considered among the mineral colours. 

Metallic pigments are sometimes mixed with adhesives or fatty substances and may be improved with artificial organic dyes. 

The examination of metallic pigments is usually restricted to a few technical tests (covering power, printing tests) and to qualitative tests (for gum, fatty substances, artificial organic dyes, metals), the ordinary methods being employed. In rare cases determinations are required of the separate metals, the methods already described in the chapter on metals fVol. I) being then used. 

---