Surface finishes lacquers

Nearly all surface finishes and coatings, with the exception of ceramic types for high-temperature applications, are based on a polymer film of some sort. They account for the use of a lot of polymer, but determining just how much and which polymers is not easy because most formulations are proprietary, and production figures do not always separate polymer and nonpolymer components. Five traditional types of surfaces finishes, lacquers, oil paints, varnishes, enamels, and latex paints, will be discussed, along with the role the polymers play in the finish. 

Grade P Density Surface area Surface finish Surface protection Magnetic properties Corrosion resistance Hardness 7.2-10 g/cm3 (for 1 g or larger) No restriction Smooth no irregularities May be plated or lacquered Same as grades S and O Surface must resist corrosion and oxidation Same as grade O... 

Hisolve. oho Chem. Industry] Glycol ether solvents solvents for paints, inks, adhesives, plastics, plasticizers, cleaners, paint removers, lacquer thiimers, dyes, brake fluids, nietal surface finishing agents reaction solvent separation and extraction solvent... 

The roughness of Class III coatings is influenced by the unevenness of the original surface. For example, a phosphated surface finished with A-7-N lacquer remains relatively rough since the phosphated surface has projections with heights greater than 30 jum [211]. Defects (cracks, chips, etc.) in Class III and IV coatings also tend to increase particle adhesion. 

Another surface finishing can be added by finally dipping the candles into a liquid lacquer, which is usually transparent and contains organic solvents, e.g. acetone, propyl-alcohol. Lacquer is only used for the realisation of special effects, e.g. matt, glossy and gold (highly disperse aluminium plus various azo-dyes), representing only 10% of annual candle production. 

The aluminium alloy Ac-120 samples of 50 X 200 mm gauge were produced with a EDT (electron discharge texturing) surface finish by Alusuisse Sierre AG, Sierre, Switzerland [40j. The surface topography was evaluated following each of four fabrication steps (a) AR, (b) pretreated in a film-forming zinc phosphate process (PP), (c) after cataphoretic lacquer BC and (d) after application of the TC lacquer. 

A number of surface finishes have been utilized over the years to protect against oxidation of solderable features. Hot air solder leveling (HASL) and rosin (lacquer) coatings, once popular, are now disappearing due to thick and irregular deposition. With the advent of fine pitch, HAL surface finishes have become a liability. These finishes have been moving more toward thin-film deposits, which are thin, uniform, and planar. Planarity is an important characteristic for fine-line applications. This realization has directed the search for viable surface finishes that fulfill this condition. 

Many older finishes can be removed with single solvents or blends of petroleum solvents and oxygenates. Varnish can be removed with mineral spirits, shellac can be stripped with alcohols, and lacquers can be removed with blends of acetates and alcohols (lacquer thinners). The removal mechanism is one of dissolving the coating, then washing the surface or wiping away the finish. This method is often used to reamalgamate or liquefy old finishes on antique items of furniture. 

Glass-reinforced aluminum foil with either a bright polished or white lacquer surface is utilized with most types of insulant. Primarily it is used as a vapor control layer or as a means of upgrading the fire properties of plastic foams, but it does give a semi-decorative finish to the insulation. It is therefore often use where the insulation is open to view but located away from direct risk of mechanical damage. 

Fluorescent lamps are manufactured by squirting a suspension of phosphor particles in an ethyl cellulose lacquer upon the inner surface of a vertical glass tube. Once the lacquer drains off, a film of peuticles is formed. The lacquer is then burned off, leaving a layer of phosphor particles. Electrodes are sealed on the tube is evacuated Hg and inert gas is added and the lamp ends are added to finish the lamp. Lamp brightness and lifetime are dependent upon the particle size distribution of the phosphor particles. The number of small particles is critical since they are low in brightness output... 

Solvent dyes are also used for tinting transparent varnishes and lacquers in the furniture and leather industries, where the surface texture of the finished articles needs to be protected but not obscured. There is also a growing demand for coloured but transparent inks for printing on the ever-increasing amounts of plastic packaging of all kinds used for the food sold in supermarkets. 

When a painting is finished, the artist often applies varnish or lacquer to the painting surface. Varnishes, and often paints, are thinned with turpentine. Turpentine can be used to remove surface varnish. Turpentine is moderately toxic if inhaled or ingested. Carbon tetrachloride, toluene, and methyl alcohol are also used to remove varnish (see Figure 10.2). Carbon tetrachloride and toluene are highly toxic if routinely inhaled. 

Film-forming finishes such as paints, lacquers, and varnishes have long been used to protect wood surfaces. The film-forming finishes are not preservatives they will not prevent decay if conditions are favorable for growth of micro-organisms. 

Polished, matt, and brushed finishes may be obtained and, in addition, other decorative effects from embossed, oxidized, and etched foils. The surface may be lacquered, anodized, or chromium-plated to prevent oxidation, and can be coloured to simulate other metals like brass and bronze. 

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