Paper web coating for low strength recycled paper material - by applying part of coating vol. at station with drying between stations, for strengthening

摘要

The coating is applied at stations. Part of the total coating is applied at each station, and the sum of the coating stations equals the amt. of coating to be applied. The paper web is dried between each coating station. Pref. coating station which gives an indirect cladding action comprises two parallel rollers with a gap between them for the paper web to pass through. Applicator jet(s) is directed at the mantle surface of one roller for the coating medium to be transferred to the web at the roller gap. Each coating station delivers only part of the total coating, and a dryer is after each station. The total vol. of coating material is pref. initially applied to one side of the web, required for that side, and the web is dried. The amt. of coating required for the other side is then applied, and the web is dried again. With station(s) part of the coating is applied and the web is dried, and a further station where the remainder of the coating is applied and the web is dried again. The amt. of coating applied to each side of the web is more than 3 g/m2, e.g. 4-8 g/m2. After each coating, the web is dried to less than 70% of the dry rating. Each station is pref. a double coating station, with a jet directed at each roller mantle. Or each station is a single applicator station, with a jet directed at only one roller mantle. In the assembly, station(s) is a double unit and station(s) is a single applicator machine. USE/ADVANTAGE - The coating of paper webs comprising recycled paper materials, adds strength and prevent dust formation. The web may be coated at high speeds, without the risk of web breaks.