Abstract: A photopolymerizable ink composition containing as essential ingredients (A) a high molecular diacrylate of epoxy resin made of bisphenol A and epichlorohydrin, (B) a urethane modified acrylate resin, (C) a urethane bond-free bifunctional photopolymerizable methacrylate monomer or oligomer, (D) a urethane bond-free polyfunctional photopolymerizable acrylate monomer or oligomer and (E) a photo-initiator, is curable upon short time exposure to ultra-violet irradiation and possesses the electrical, mechanical and chemical properties indispensable to a protective film for use in printed circuit boards.

Abstract: A mobile floor cleaning and polishing machine comprising a wheel-supported chassis having thereon a turntable rotatable about a normally vertical axis. The turntable supports abrasive-ejecting mechanism including a generally rectangular nozzle from which granular, pelleted or pulverous abrasive may be discharged at high velocity, downwardly against the floor or other surface to be cleaned. By adjusting the angle of the rectangular nozzle with respect to the direction of advance of the machine, the width of the area treated in a single pass of the machine, may be controlled as desired. Spent abrasive is automatically recovered, cleaned and stored for re-use. Means are disclosed for oscillating the ejector means back and forth relatively to the chassis, in the direction of travel of the machine.