Non-Asbestos Gaskets

No one single fiber has been found which can act as a one-to-one replacement for asbestos in gasket formulations. Beater addition gaskets, compressed gaskets, resin impregnated papers and formed-in-place gaskets all use a blend of organic fibers in combination with inorganic fibers and/or fillers to tailor the performance to a particular application. The most common organic fibers used are cellulose and aramid pulps to aid in processing, as well as provide tensile strength, heat/crush resistance and fluid resistance. However, the use of cellulose pulp usually results in lower tensile strength, lower flexibility, sheet embrittlement and lower temperature resistance while aramid pulp results in high raw materials cost, and in many cases, poor die cutting and other manufacturing problems. In addition, aramid fiber may exhibit poor bonding to the latex and styrene-butadiene rubber or nitrile rubber matrices normally used in gasket sheet fabrication.

Sterling acrylic (polyacrylonitrile) pulps, fibers and fiber blends are a new addition to the selection list which can provide reduced cost, improved processability and gasket uniformity, greater gasket flexibility, higher tear strengths and improved thermal resistance, among other enhanced qualities. Provided in the form of fibrillated fibers, short/small diameter geometry microfibers, or with newly developed second generation acrylic polymer chemistry for higher heat and hydrolysis resistance, Sterling fibers offer engineering advantages combined with cost savings. All three types of fibers are being used commercially and can be provided in production quantities.

Technical documents