Printers blankets and method of making printers blankets

摘要

953,786. Printing press blankets. UNITED STATES RUBBER CO. Feb. 28, 1962 [April 17, 1961], No. 7792/62. Heading B6C. A method of making a lithographic printer's blanket for use in an offset press comprises embedding a multi-cord fabric in a layer of unvulcanized elastomeric compound having a Shore "A" durometer value in the range 30-100, coating one surface of said carcass with a facing layer of an unvulcanized elastomeric compound having a Shore " A " durometer value of 40-70, vulcanizing the compounds of both layers, and cutting the coated carcass to the size of the finished blanket. In one example, a tire-cord fabric 23 having warp and weft threads 24, 25 is embedded in a layer 22 of a polyurethane compound comprising a mixture of polyurethane rubber, stearic acid, carbon black and dicumyl peroxide. The resulting carcass is coated with a layer 21 of a polyurethane compound comprising a mixture of a polyurethane rubber, stearic acid, carbon black and dicumyl peroxide which is mixed with methyl ethyl ketone until a dough is formed, the dough being spread on the carcass as a facing layer. The coated carcass is vulcanized in a dry inert atmosphere, e.g. nitrogen gas. In a second example, a blanket is cast on a tirecord fabric from a liquid pre-polymer using toluene diisocyanate as a cross-linking agent. This carcass is coated with the facing compound of the first example prior to vulcanization in a dry inert atmosphere. The blanket may be attached to the press cylinder through clamps and clamp bolts 28, 29, Fig. 3A, or holes 27 having metal inserts 31, Fig. 4, may be provided in the scalloped ends 26 of the blanket. In yet another method of attachment, a layer of elastomer is removed in the area of the scollops and a thickening of the weft threads 25 is effected in this region.