| 摘要 |
<p>854,119. Printers' blankets. EEKHOUT, F. J. Sept. 29, 1958 [May 27, 1958], No. 31094/58. Class 100(2) A method of processing a printers' offset rubber blanket comprises applying a preparation composed of a polyester, an isocyanate or polyisocyanate, a cellulose ester and an organic solvent for said substances to the surface of the blanket, and drying the treated blanket at an elevated temperature, so as to form a closed surface which absorbs little or no water and gives off substantially all the ink to the paper, the ink and rubber dissolving in each other as little as possible. The blanket is previously cleaned with ethylacetate and/or butylacetate. The composition to be applied may be 50 gms. "Difinal" M and 40 gms. "Difinal" G. K. (Registered Trade Marks) (hydroxy-terminated polyesters), 830 gms. ethylacetate and 630 gms. butylacetate (solvent), 35 gms. "Desmodin" R (Registered Trade Mark) (a diisocyanate), and 15 gms. of a 15 % solution of nitrocellulose in acetone, intimately mixed to form a homogeneous solution. The blanket may be stretched in a roller, cleaned, and run through a flat tray containing the solution, being then dried by a plurality of spaced-apart infra-red lamps 30-40 cms. from the roller. The treatment is repeated several times, and the blanket then left for forty-eight hours. The drying causes condensation of the polyester with the isocyanate or polyisocyanate, forming a polyurethene resin. The components of the solution should be mixed only shortly before treatment.</p> |
