Micarta

a laminated plastic material based on paper and synthetic resins. Phenol-formaldehyde resins are most frequently used as the binder; melamine-formaldehyde and epoxy-phenol-anilinoformaldehyde resins are used less frequently. The resin content of Micarta is 40-55 percent. It is sometimes wrapped with red copper electrolytic foil, coated with cotton, glass, or asbestos fabrics, or reinforced with a metal screen. Several brands of Micarta are produced for various uses.

Micarta has high mechanical strength and good electrical insulation properties. Other properties are as follows: density, 1.25 g/cm³; Martens yield temperature, 150°-160° C; tensile strength, 70-100 meganewtons per square meter (MN/m²), or 700-1,000 kilograms-force per sq cm (kgf/cm²); static bending strength (according to base), 80-140 MN/m²(800-1,400 kgf/cm²); specific resilience, 1.3-1.5 kilojoules per square meter (kJ/m²), or 13-15 kgf-cm/cm²; water absorption in 24 hours, 0.3-0.6 g/dm²; specific electrical surface resistivity, 10¹⁰-10¹² ohms; tangent of the dielectric phase angle at 10³ kilohertz, 0.07-0.10.

To produce Micarta sheets, paper is impregnated with an alcohol or aqueous-alcohol solution of a resol resin or with a molten resin under pressure. The impregnated sheets are dried, cut, assembled into packets, pressed at 150°-160° C, and then cooled under pressure. The Micarta sometimes undergoes additional heat treatment (heating to 120°-130° C in stages). Most Micarta articles are produced by mechanical processing.

Micarta is used as electrical insulating material for prolonged use at temperatures from -65° to +105° C and in the production of panels, covers, sleeves, gears, and washers, as well as in furniture production. Foil-covered Micarta is used for the production of printing plates.