Protective film abrasion resistant

The excellent chemical resistance and physical properties of PVA resins have resulted in broad industrial use. The polymer is an excellent adhesive and possesses solvent-, oil-, and grease-resistant properties matched by few other polymers. Poly(vinyl alcohol) films exhibit high tensile strength, abrasion resistance, and oxygen barrier properties which, under dry conditions, are superior to those of any other known polymer. The polymer s low surface tension provides for excellent emulsification and protective coUoid properties. 

With the flexibility of the blown film extrusion process, one-step production of wide multilayer films is possible. Incorporating a built-in adhesive layer, PVDF films can be laminated directly onto various thermo and thermoset plastics or primed metal substrates. PVDF films can protect the esthetics of UV sensitive substrates while also providing a thermal, chemical, and abrasion-resistant barrier. Recently, white PVDF films have been commercialized that are of full opacity in the UV range of 290 00 Most recently,... 

Other encapsulation applications of polymers for specific designs Include soil, ultraviolet, and abrasion-resistant front covers. The cover can serve as a transparent structural superstrata. Substrate support designs require a hard, durable front cover film to protect the relatively soft pottant from mechanical damages and excess soil accumulation. A polymeric front cover must be low In cost, highly transparent, and weather resistant to compete with glass. For applications out of the optical path between the sun and the solar cells (adhesives. Insulation, edge seals, gaskets) requirements for polymeric use In encapsulation are the same as for other applications. 

Corrosion rates and those of mechanochemical wear of stainless steels and alloys widely applied in friction joints of chemical equipment are presented in Table 4.2 [30]. Owing to the formation of passivating protective films on contact with hostile media, these materials display high corrosion resistance. As can be seen from the table, corrosion rates grow during friction by a factor of thousand. Under such conditions, the material wears largely due to corrosion even in a weak solution of sulfuric acid for both sliding friction over a softer material (PE) and under abrasive action (ceramics). 

T. Wydeven developed a plasma process that significantly improves the hardness of optical lenses and, consequently, leads to greater scratch resistance (7. Vinyl-trimethoxysilane films were deposited on transparent polycarbonate lenses by plasma polymerization. The adherent, clear films protect the substrate from abrasion and also serve as antireflection coatings. Post-treatment of the vinyltrimethoxysilane films in an oxygen glow discharge fui ther improved the abrasion resistance. 

Vacuum metallizing of polymer films, such as cellulose acetate, butyrate, and Mylar, is performed in essentially the same way. Film rolls are unreeled and rewound during the deposition process to metallize the desired surface. A protective abrasion-resistant coating is then applied to the metallized surface in an automatic coating machine. 

Epoxy resins are generally not used alone but require a reaction partner in order to be cured (hardened). A large number of reaction partners may be used for curing at elevated or at room temperature. The cured films have high adhesion, flexibility, hardness, abrasion resistance, resistance to chemicals, and corrosion protection. In 1995 ca. 700000 t of epoxy resins were used worldwide by the coating industry (including civil engineering applications). 

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