| 摘要 |
1283446 Coating paper NATIONAL CASH REGISTER CO 17 Nov 1970 [15 Dec 1969] 54589/70 Headings B2E and B1C [Also in Divisions C3 and D2] Paper is coated with an aqueous dispersion of a meltable, oil soluble but water-insoluble acidic polymeric material is used to coat paper by such methods as roll, air-knife and trailing blade coating. The preferred polymers are those having free OH groups such as phenolaldehyde and phenol-acetylene resins. The dispersion preferably includes a hydrophilic colloid forming binder such as raw starch and may also include SiO 2 . Other additives include clay, styrene-butadiene latex, CaCO 3 , a dispersant such as a glassy phosphate, surfactants such as a sodium salt of a polyelectrolyte, lubricants such as calcium stearate, germicides, fungicides and defoaming agents. A typical coating composition comprises in % wt polymer 15; starch 9; silica 3; latex 5; clay 59; CaCO 3 9; and water. In apparatus for making the aqueous dispersion an aqueous slurry of polymer, starch and silica is pumped to an annular chamber 26 where a jet 24 discharges steam at a higher pressure causing melting and subdivision of the polymer particles and formation of an emulsion in the tube 27. Excess of uncondensed steam is released in flash chamber 33, the thus cooled liquid dispersion being discharged at 35. |
