Protective coatings and films

Practically all cellulose acetate manufactured at the present time is the acetone-soluble product, ranging from 37% to 41% acetyl content. Cellulose mixed esters now produced in quantity include cellulose acetate propionate of 33% propionyl content, cellulose acetate butyrate of 16% butyryl content, both of which are used largely for protective coatings and films, and cellulose acetate butyrate of 36% butyryl content used for plastics. 

PROTECTIVE COATING. A film or thin layer of metal glass of paint applied to a substrate primarily to inhibit corrosion, and secondarily for decorative purposes, Metals such as nickel, chromium, copper, and tin are electrodeposited on the base metal paints may be sprayed or brushed on. Vitreous enamel coatings are also used these require baking. Zinc coating are applied by continuous bath process in which a strip of ferrous metal is passed through molten zinc. 

In the last several years, polymer thin film deposition using chemical vapor deposition (CVD) has become increasingly popular. CVD of polymers offers numerous unique advantages over other polymer synthesis techniques and has been exploited for a multitude of applications in microelectronics, optical devices, biomedical industry, corrosion resistant and protective coatings, and even in the automobile industry. CVD of polymers (also referred to as chemical vapor polymerization, CVP, or sometimes Vapor Deposition Polymerization, VDP) differs from inorganic CVD (such as for metallic or ceramic thin films) and must be developed and optimized... 

Coatings and films Most paints and coatings degrade by a photoelectrochemical mechanism. Applications are summarized that include protective coatings for automobiles, encapsulants for microelectronic devices, electrocatalysts, and microencapsulation techniques for controlled release of electroactive components. 

The preparation and properties of glow-discharge polymerized or-ganotin films have been studied in the past(l) and such films have been used as insulating layers on microelectronic devices, as protective coatings, and as intermediate adhesive layers.(2,3) An up-to-date literature review on the production and properties of the organometallic films prepared by plasma polymerization has been reported by the authors in another paper.(4)... 

Coatings. The solid dimer polyamide resins are useful as protective coatings and inks on many substrates, especially flexibile ones like polyolefin film, paper, fiberboard, and metal foils. Thus, paper converters use these resins by applying them from solvent by roller-... 

Protective metal coats and films on the working surfaces of rubbing bodies are frequently used as protectors of friction joints. These films of more electronegative or more electropositive metals than the substrate can be ap>-plied on the contact surface. The former function as protectors, the latter passivate the substrate material operating as sacrificial anodes. 

The corrosion reactions described above require an active (i.e., mainly bare) metal surface. In practice, however, many metals tend to form protective hlms that can have a major influence on the electrolytic process. Dense films provide protection and are thus referred to as protective coatings or films. A protective iron oxide film is known to form, for example, in boiler pipes. In contrast, porous rust layers provide no protection. The good resistance of aluminum, which is the result of an AI2O3 film forming in air, can also be produced artihcially by anodic oxidation. 

Electrochemical inhibitors retard or prevent the anodic and/or cathodic partial reactions (i.e they influence the reaction at the metal/corrosive medium interface). Chemical inhibitors can react both with the material and form protective coatings and with the medium itself or its constituents and thus diminish its aggressiveness. Physical inhibitors form adsorption layers on the metal surface, which block the corrosion reaction. Inhibitors that influence the electrochemical electrode reactions are subdivided according to their mode of action and site of action in the area of the metal/ medium phase boundary, with the subdivision being between interface inhibitors, electrolyte film inhibitors, membrane inhibitors, and passivators. 

M. N. Gardos in Protective Coatings and Thin Films, Y. Pauleau and P. B. Barna (Eds), Kluwer Academic Publishers, The Netheriands 1997, 185-196. 

Uses Monomer for polymer applies., polyester films, protective coatings and paints reduction of reaction time in esterification Manuf/Distrib. Aldrich Eastman Fluka... 

Uses Thickener carrier for active substances protective coating antistat, film-former, emulsifier in cosmetics, personal care prods. Features Hydrogel polymer substantive to skin and hair Trade Names Hypan QT100... 

Toxicology LDLo (oral, rat) 3200 mg/kg, (IP, rat) 800 mg/kg mod. toxic by IP route TSCA listed Precaution Combustible Hazardous Decomp. Prods. CO, CO2 heated to decomp., emits acrid smoke and fumes NFPA Flammability 1, Reactivity 0 Uses Monomer for polymer applies., polyester films, protective coatings and paints reduction of reaction time in esterification Manuf./Distrib. Aldrich http //www.sigma-aldrich.com, Eastman http //www.eastman.com, Fluka http //www.sigma-aidrich. com... 

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