Coated front paper prodn. for pressure-sensitive recording paper - by simultaneous application of front coat and back size coat with aq soln pref starch soln using rollers fed by grooved dosing doctors.

摘要

Prodn of coated front (CF) paper for pressure-sensitive recording paper by applying a coating contg colour-reactive inorg pigment (I) comprises: (a) sizing the paper completely in bulk; and (b) coating with the CF coat between a pair of transfer rollers adjusted with a gap or min pressing pressure. Rotary and driven grooved doctors supply predosed vols of CF coating compsn (II) to one roller and aq soln (III) to the other, (II) and (III) being transferred to opposite sides of the paper. Pref (II) contains over 40 (wt)% solids. In addn to (I), up to 30% of the total pigment may be a colour-inert pigment comprising CaCO3, kaolin, BaSO4, talc, chlorite, pptd silicate, Al(OH)3 and/or inhibited starch. (II) is applied in an amt of 3-6 g/m2 (dry), with 3.5-5 g/m2 (I). (III) is a starch soln. ADVANTAGE - A uniform CF coat is obtd without using an excessive amt of (I); (II) contg over 40% solids and with a wide range of viscosities can be used, with or without addn of inert pigment; the process can be carried out in the paper machine; and both coatings can be applied and dried simultaneously, which is economical.