Coated abrasive markets

Cleaning for Resale or Disposal. The solids, cleaned of oil and salt, may be marketed for construction or other industrial use. For example, a clean round-grained sand may be recycled as a frac or gravel pack material. Sand blasting and the manufacture of hard coatings, abrasives, and glass are other end uses for the cleaned solids. Frequently, the major obstacles to resale of the cleaned solids are the identification of prospective markets and the justification of the treatment and transportation costs to the client. 

For example, the abrasion-resistant coatings based on a silicone-silica hybrid (33) have provided a scratch- and mar-resistant finish for polycarbonate as well as metals. The chemistry involved is discussed by Vincent, Kimball and Boundy (3iL). The coating consists of polysiloxane and silane-modified submicron silica particles, microscopically dispersed in the solution. The coating is then cured at elevated temperatures. Currently, this type of abrasion resistant coating is marketed in the U.S. by Dow Corning and General Electric Company. 

Abrasives. Grinding wheels (bonded abrasives) and sandpaper (coated abrasives) are made from abrasive grit bonded by phenolic resin. The abrasive grit may be alumina for cutting and polishing steel, or silicon carbide for handling glass, ceramics, and stone. This uses 1 percent of the phenolic resin market. 

In the electrical/electronic market, acrylic film adhesives are applied to flexible printed circuits. Radiation-curable acrylates are employed as laminating adhesives (furniture) and binders for coated abrasives (Table 9). 

Phenolics are used in two main categories of abrasives. Bonded abrasives are three-dimensional structures such as grinding wheels and snagging wheels, and coated abrasives include sandpaper, sanding discs, and belts. According to the data reported in Table 1, the markets for abrasives have decreased by 11 million lb during the years from 1983 to 1987. 

Power demands may vary from hand operations utilizing minimal effort to abrasive planers that consume several hundred horsepower. Because of the wide variety of applications and the vast array of finishing and stock removal requirements, there are many types of coated abrasive designs and products on the market. 

There are many market areas in which coated abrasives are used automotive, industrial metals and fabricators, sporting goods, wood, retail, furniture, aerospace and transportation, just to name a few. For example, the planer belt markets utilize coated abrasive belts to plane rough lumber down to finished size, instead of traditional knife planers. The advantages of abrasives are that they can cut faster, last longer than knives, and are not as sensitive to being damaged by nails or hard items sometimes found in boards. 

Sol—Gel Sintered Aluminum Oxide. A new and much more versatile sintered alumina abrasive is now produced from aluminum monohydrate, with or without small additions of modifiers such as magnesia, by the sol—gel process (see Sol-gel technology). The first modified sol—gel abrasive on the market, Cubitron, was patented (27) and produced by the 3M Corporation for products such as coated belts and disks. The success of this material promoted intensive research into sol—gel abrasives. 

Thermoplastics which are used for corrosion protection can be applied in coatings as thin as 0.025 mm by solution techniques and in excess of 5 mm by extrusion or plastisol dipping. They are used where environmental resistance, chemical resistance, abrasion resistance, sound deadening or cushioning are required. They are used in those market areas that necessitate metallic mechanical strength plus thermoplastic corrosion resistance. 

Epoxy-silica hybrids are well known for their abrasion resistance and low thermal expansion due to the presence of nanostructured bi-continuous domains. Most recently they have entered the market as anticorrosion coatings in the marine held, for yachts and for large metal vessels, such as oil tankers, and in particular for cargo or ballast tanks and on hulls (Figure 4.9). 

In 2007 a new line of organofunctional and alkylsilane water-based sol gel products called Dynasylan Hydrosil (trademarks of Evonik) entered the market.19 They provide good corrosion and abrasion protection for valuable metal surfaces. They also provide coatings of excellent adhesion, without the need to use chromium(vi), a carcinogenic metal ion still widespread in corrosion treatment formulations. 

No-wax tile has long been important in the residential market. Such products have a high gloss surface coating that resists abrasion and soiling. When properly designed and maintained, no-wax tile retains its shiny appearance for an extended period of time without application of floor polish. 

They are flexible, exhibit excellent abrasion resistance, resistance to most household reagents and do not rely on mechanical sanding to achieve intercoat adhesion. These environmentally friendly systems address the issues of occupational health and safety in a market traditionally dominated by solvent-based coatings (section 2.3.8). 

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