Doctor blades, esp. for high-speed paper coating - made of polyamide 6 or 66 reinforced with fibre of higher thermal conductivity, esp. carbon@ fibre

摘要

Use of fibre-reinforced plastic (I) is claimed for rod- or blade-shaped spreaders (II) for applying, metering and levelling aq., pigmented coating materials on sheet-like substrate materials, e.g. paper, cardboard or foil, in high-speed coating machines. (I) consists of 60-90 wt.% polyamide 6 or 66 (III) and 10-40 wt.% reinforcing fibre (IV) with thermal conductivity higher than (III). Pref. (I) has elastic modulus, 11,000-16,000 MPa; coefft. of sliding friction, 0.16-0.20: thermal conductivity, 0.6-0.9 W/K/m. (IV) is metal, carbon, graphite, SiC and/or AlN fibre, embedded in (III) as individual fibres or as knitted or woven fabric, lay-up or mat. USE/ADVANTAGE - (I) are useful esp. as coating bars and doctor blades for coating paper with aq. dispersions of pigments and binders etc., in high-speed coating machines. W.r.t. prior-art plastic blades etc., (I) are subject to less abrasive wear and have higher thermal conductivity i.e. longer service life with less overheating.