Paint and coatings

Australian standard was developed for similar purposes. The standard sets out a method for assessing the ability of a paint finish to resist bloeking, when the paint coating is placed in intimate contact with another surface, for a prescribed period, imder set temperature and pressure, and subsequently separated from that surface. 

Blocking resistance of architectural paints is evaluated according to a different standard. Similar 10 point scale is used but temperature, time, and weight differ which are 48-52°C, 30 min., and 1000 g, respectively. 

The international and national standards specify requirements and methods of test for liquid epoxy paints and internal coatings of such paints in steel pipes and fittings for the conveyance of non-corrosive gas. It also deals with the application of the paint. Other paints or paint systems are not excluded provided they comply with the requirements given in the standard. The coating consists of one layer, which is normally shop-applied on blast-cleaned steel by airless spray or Ollier suitable spraying techniques. The applied and cured paint film must be smooth to give the desired reduction in friction. Brush application is only used for small repair jobs. 

Paints and coatings are applied to a variety of different substrates, for example, metal, masonry, wood or engineering plastics. The corresponding objects range frombuildings and 

According to A STM D 6-00, paint is a pigmented coating and a coating is a liquid, liquefiable, or mastic composition that is converted to a solid, protective, decorative, or functional film after application as a thin layer.t J A paint can also be defined as a fluid material that when spread over a surface in the form of a thin layer, will form a solid, adherent, and cohesive film.f l 

Paints have been used for decorative purposes for many centuries. They were used about 25,000 years ago by primitive men who used them in caves to outline the shape of animals they hunted. 

The paintings produced in ancient Eg5q)t have been shown to incorporate gum arabic, gelatin, egg white, and beeswax. In classical Greece, paints were used extensively in sculpture (for hair, lips, and eyes of statues), architecture, and in painting ships as well as in interior decoration. 

By the late eighteenth century, demands for paints of all t)q)es had increased such that it became worthwhile for businesses to make paints and varnishes for widespread use. l The industrial revolution had a major effect on the development of the paint industry due to the demand for paint to protect machinery, and this marked the start of modem paints. An acceleration of the rate of scientific discovery had a growing impact on the development of paints from the eighteenth century to the present day. Pmssian blue, the first artificial pigment with a known chemistry, was discovered in 1704. 1 

Paints were based mainly on drying oils, and this t5q)e remained in common use until about the end of the first quarter of the twentieth century 

The second largest user of pigments is the paint and coatings industry, which is not surprising with a world demand for paint in 2000 of 25 M tonnes. The make up of the end users for this volume of paint is given in Table 2.13. 

A very wide range of plastics are coloured with pigments including PVC, polystyrene, polyurethane, polyamide, polycarbonate, polyester, elastomers, thermosets and thermoplastics. The choice of pigment is obviously dependent on which plastic 

Many plastic materials are colonred nsing pre-dispersed concentrates of the colonr in the same polymer or a compatible resin these are known as masterbatches. Masterbatches overcome the problems of dispersing the conventional solid pigments into the polymer matrix. 

This section ordy includes plasticizers which are used in paints and coatings used in civil engineering applications. Formation of permeable films, such as in controlled release applications is fully discussed in Section 13.21 devoted to pharmaceutical products. 

Iron blue pigments are used in the paint industry, e.g. for full, dark blue colors for automotive finishes. A full shade with good hiding power is produced by 4-8% iron blue pigments. 

Adding Vater-soluble iron blue pigment directly to the aqueous phase can produce blue paper. Alternatively, a suitable iron blue pigment can be ground together with a water-soluble binder, applied to the paper, dried, and glazed (quantity applied ca. 8% in the dispersion). 

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Some of the mixed xylenes that ate produced are used as solvents in the paints and coatings industry (see Solvents, industrial). However, this use has declined, particularly in the United States as environmental efforts to reduce hydrocarbon emissions into the air have increased. 

Solutions of rhamsan have high viscosity at low shear rates and low gum concentrations (90). The rheological properties and suspension capabiUty combined with excellent salt compatibihty, make it useful for several industrial apphcations including agricultural fertilizer suspensions, pigment suspensions, cleaners, and paints and coatings. 

Lead Tetroxide. Lead tetroxide (red lead minium lead orthoplumbite), Pb O, is a brilliant orange-red pigment which accounted for U.S. shipments of 17,780 t ia 1977, mainly to the ceramics and storage battery iadustries (40). U.S. shipments ia 1993 amounted to approximately 12,000 t. The decrease ia usage siace 1973 (19,000 t) is attributable to discontinued use ia the paint and coatings (qv) iadustry, and alterations ia mbber and ceramics (qv) markets. It is iasoluble ia water and alcohol, and dissolves ia acetic acid or hot hydrochloric acid. Red lead is manufactured by heating lead monoxide ia a reverberatory furnace ia the preseace of air at 450—500°C uatil the desired oxidative composition is obtaiaed. 

Dealing with Eead-Based Paint M Practical Guide for Consumers, National Paint and Coatings Association (NPCA), Washington, D.C. 

There are approximately 114 paint remover manufacturers in the United States. Among them are companies that speciali2e in the manufacture of paint removers only, paint and coating manufacturers that produce a line of paint removers, specialty products manufacturers, and other manufacturers of finish removers for unique or special appHcations. Each group of paint remover manufacturer can be divided into retail or industrial products. A Hst of U.S. paint remover manufacturers is given in Table 2. 

Methylene Chloride Consumption By Paint and Coating EemovalGroups, Paint Remover Manufacturer s Association, 1992. 

In general, polycarbonate resins have fair chemical resistance to aqueous solutions of acids or bases, as well as to fats and oils. Chemical attack by amines or ammonium hydroxide occurs, however, and aUphatic and aromatic hydrocarbons promote crazing of stressed molded samples. Eor these reasons, care must be exercised in the choice of solvents for painting and coating operations. Eor sheet appHcations, polycarbonate is commonly coated with a sihcone—sihcate hardcoat which provides abrasion resistance as well as increased solvent resistance. Coated films are also available. 

Dimethylethanolamine, diethylethanolaniine, and thek derivatives are used in pesticides, corrosion inhibitors, dmgs and pharmaceuticals, emulsification, paints and coatings, metal fabrication and finishing, petroleum and petroleum products, and plastics and resins (226). 

Use as Solvent. Toluene is more important as a solvent than either benzene or xylene. Solvent use accounts for ca 14% of the total U.S. toluene demand for chemicals. About two-thirds of the solvent use is in paints and coatings the remainder is in adhesives, inks, pharmaceuticals, and other formulated products utilizing a solvent carrier. Use of toluene as solvent in surface coatings has been declining, primarily because of various environmental and health regulations. It is being replaced by other solvents, such as esters and ketones, and by changing the product formulation to use either fully soHd systems or water-based emulsion systems. 

G. E. E. Brewer, paper presented at Electrocoat 72, Electrocoating Committee and the National Paint and Coatings Association, Chicago, lU., Oct. 2-4,1972. 

Butyl acetate [123-86-4], one of the more important derivatives of -butyl alcohol produced commercially, is employed as a solvent ia rapid dryiag paints and coatings. In some instances, butyl acetate, has replaced ethoxyethyl acetate [111-15-9] due to the latter s reported toxicity and... 

Calcium carbonate is one of the most common filler/extenders used in the paint and coatings industry. Consumer and contractor paint formulas can include products from submicrometer size to coarse mesh sizes. The main function of calcium carbonate in paint is as a low cost extender. It is also used to improve brightness, appHcation properties, stabiHty, and exposure resistance. Coarse products help to lower gloss and sheen or even provide textured finishes. The selection of product type and particle size is deterrnined by the desired performance and cost of the coating. 

Airex Th. Goldschmidt AG silicone—organic defoamers for paints and coatings... 

Two-roll mills are used rnainlv for preparing color pastes for the ink, paint, and coating industries. There are a few applications in heaw-diitv blending of rubber stocks, for which corrugated and masticating rolls are often used. 

Paints and coatings for automobiles have not been immune to damage by air polluhon. Wolff and co-workers (13) found that damage to automobile finishes was the result of scarring by calcium sulfate crystals formed when sulfuric acid in rain or dew reacted with dry deposited calcium. 

The solubility parameter concept has found widespread use in predicting the compatibility of components used in paints and coatings, and the patent literature contains numerous references to the solubility parameter or solubility parameter ranges in specifying formulations. Its use in predicting adhesion should apply in... 

Lead is an element used in many industrial processes and also has been used in fuels and coatings. Tetraethyl lead was added to gasoline to improve performance as a motor fuel, and elemental lead was extensively used in paints and coatings to improve coverage and durability until the 1970s, when phase-out efforts began to reduce lead emissions to the environment. 

The subject of paints and coatings is complicated and covers a large number of both uses and conditions. There are few publications that describe all aspects that are particularly suitable for an engineer. There are limited publications on such specialized subjects as the protection of iron and steel. 

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