Printing blankets

摘要

1,006,534. Printing apparatus; blankets. W. R. GRACE & CO. May 13, 1964 [May 16, 1963], No. 19980/64. Heading B6C. A printing blanket for use in screen printing, which is a vulcanized, endless, unitary structure, comprises a loop of a base ply of textile material, e.g. duck, a layer of substantially unstretchable cord, e.g. glass yarn, in the form of a continuous length wound longitudinally of the loop as an helix enclosing the entire loop of the ply and at least one ply of textile material covering the cord layer, the or each covering ply and each turn of the cord being surrounded by and embedded in a vulcanized rubber. Each turn of the cord save for its rubber embedment lies in immediate proximity to the base ply and, instead of one length of cord enclosing the entire loop, two lengths may be employed which extend, respectively, as left-hand and right-hand windings from the centre of the base ply to its margin. In the embodiment shown, a base ply 12 of duck carries a rubber coating 13. Two helices 14, of rubber-coated rayon or glass yarns, having right-hand and left-hand windings, are wound on the top of the coating 13. The covering duck ply 15 is rubber coated on each face whilst a further duck ply 19 carries a rubber coating 18. If required, the top surface of the ply 19 carries a rubber coating 21 which later becomes the working surface of the blanket. The assembly of plies and yarns is vulcanized in a press the heat and pressure of which is such that in the resulting blanket the rubber layers are indistinguishable and form a solid rubber mass in which all of the fibrous elements, whether yarn or fabric, are embedded. The coatings 13, 16, 17, 18 and 21 and the coatings of the rayon and glass yarns may be a vulcanizable neoprene or a butadiene acrylonitrile rubber compound.