The Premium RockTM Series was developed to meet the demands of the paper industry rolls requiring 0-1 P&J Hardness. Based on innovative formulas, these roll coverings achieve more than just the required hardness. The roll covers provide superior perfor-mance in chemical resistance, hardness stability, hysteresis, heat stability, abrasion re-sistance, thermal expansion and friction requirements. The dynamic stability of the Pre-mium RockTM Series roll coverings make for an ideal choice under a broad spectrum of operating conditions. Exposure to paper mill chemicals, nip loads, and high speeds are no threat to the high performance characteristics of these advanced bone hard roll cov-erings. Now, Premium T RockTM and Premium TT RockTM take the battle of the “stickies” to a higher performance level. Each of these bone hard cover compound contains an additive package that keeps the “stickies” at bay and allows most clean ups to be com-pleted with a simple water hose.
Press Rollers pose unique challenges to the dynamic properties of a roll covering. Oper-ating under high pressure and speed, a rubber covering is forced to change shape passing through a nip. A roll cover with good hysteresis properties, like Premium Rock, readily recovers its shape upon displacement by the nip. Many other coverings have only fair to medium hysteresis properties. The energy produced by the nip is not efficiently expend-ed in the recovery and is converted to heat. Excessive heat build up can lead to many other problems in the press including hot spots and shortened roll cover life.