Coatings chemical resistance

CWC-related chemicals must be handled with great care. Persons handling toxic chemicals must be specially trained for the work. When toxic samples are handled, decontamination solution, protective masks, and autoinjectors of nerve agent antidotes must always be available, and no one must ever work alone. Individual protective gear such as laboratory coats, chemically resistant protective gloves, and safety goggles are essential during sample preparation. Toxic samples must always be prepared in a fume cupboard. 

Laminate coatings Chemical resistance Abrasion resistance Adhesion Storage tanks in refineries and oil fields Water purification units Paper industry... 

Epoxy-tar coatings Chemical resistance Bacterial resistance Corrosion resistance Reasonable weathering resistance Effluent plants Sewage works Chemical processing plants... 

Chempln. [Sullivan Qiem. Coatings] Chemical-resistant coatings. 

Polyetherketone (PEK) - Thermoplastic with excellent high-temperature properties and thermal stability. Used in advanced composites, wire coating, chemical-resistant filters, integrated circuit wafer carriers, and bearings. Synthesized by polyarolyation or polyetherization. 

USE In apparel and household furnishings simulated fur coats chemically resistant clothing. In making wigs and doll hair the hair can be washed, combed, t, and in some instances, redyed. 

Uses Phenolic for heat-curable phenolic/epoxide resin combinations, can coatings, chemically resist, protective coatings Properties Dilutable with MEK, MIBK, ethyl acetate, butyl acetate, methoxypropyl acetate, methoxypropanol dens. = 1.05 g/cm (20 C) dynamic vise. 180-300 mPa S flash pt. = 43 C 63-67% NV Storage 6 mos min. shelf life stored in original containers below 25 C Phenodur PR 260/68B [Solutia]... 

Uses Thermoset used in chem. processing industry, pulp and paper mills, corrosive-resist, applies., coatings, chemically-resist./fiber-reinforced piping/tanks food-contact crosslinked polyester resins Manuf./Distrib. Alpha/Owens-Coming Ashland Chemcentral Cook Composites Polymers Dow Eastech ISP Monomer-Polymer Dajac Labs... 

C Polyacrylate Polystyrene Reinforcing veils for gel coats Chemically resistant barrier layers... 

Carbon (DLC) - hard coat, chemically resistant, low friction... 

Flexible foams are used in mattresses, cushions, and safety applications. Rigid and semiflexible foams are used in structural applications and to encapsulate sensitive components to protect them against shock, vibration, and moisture. Foam coatings are tough, hard, flexible, and chemically resistant. 

Epoxy phenoHc coatings either are made by blending of a soHd epoxy resin with a phenoHc resin or are the products of the precondensation of a mixture of two resins. A three-dimensional stmcture is formed during curing which combines the good adhesion properties of the epoxy resin with the high chemical resistance properties of the phenoHc resin. The balanced properties of epoxy phenoHc coatings have made them almost universal in their appHcation on food cans. 

Another important function of metallic coatings is to provide wear resistance. Hard chromium, electroless nickel, composites of nickel and diamond, or diffusion or vapor-phase deposits of sUicon carbide [409-21-2], SiC , SiC tungsten carbide [56780-56-4], WC and boron carbide [12069-32-8], B4C, are examples. Chemical resistance at high temperatures is provided by aUoys of aluminum and platinum [7440-06-4] or other precious metals (10—14). 

The critical property for conformal coatings is resistance to chemicals, moisture, and abrasion. Other properties, such as the coefficient of thermal expansion, thermal conductivity, flexibiHty, and modulus of elasticity, are significant only in particular appHcations. The dielectric constant and loss tangent of the conformal coating are important for high speed appHcations. 

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. 

Nitrocellulose based lacquers often contain short or medium oil alkyds to improve flexibiUty and adhesion. The most commonly used are short oil non drying alkyds. Amino resins or urethane resins with residual isocyanate functional groups may be added to cross-link the coating film for improved solvent and chemical resistance. The principal appHcations are furniture coatings, top lacquer for printed paper, and automotive refinishing primers. 

Uralkyds have superior adhesion, hardness, abrasion resistance, durabiHty, and chemical resistance to the unmodified alkyds. They find appHcations in wood floor finishes, marine coatings, metal primers, and maintenance paints. 

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