| 摘要 |
1289314 Polishing pads MINNESOTA MINING & MFG Co 13 Nov 1969 [14 Nov 1968] 55713/69 Heading A4F [Also in Divisions B2 B5 and C4] Polyester strips, e.g. fibres and films which can readily bond to synthetic resin coatings are produced by immersing a hot amorphous polyester strip in a quench solution of an isocyanate dissolved in and reacted with a stoichiometric excess of at least one liquid monohydric alcohol, rinsing the quenched strip in a liquid which is compatible and miscible with the quench solution to remove excess quench solution from the surface of the solidified fibre or film and tensilizing the quenched and rinsed strip. Tensilizing means stretching in the longitudinal direction at a stretch ratio sufficiently high and at a temperature such that the polyester material of the strip becomes crystalline and oriented, whereby its tensile strength is increased. In an example, filaments produced in accordance with the invention are crimped, out to about 5 cm length, converted into a lofty, open, low density, non-woven fleece about 1À25 cm thick, and slurry comprising 353 parts of 81% thermosetting phenol-fermaldehyde resin, 94 parts of a polyamide resin, 210 parts of ethylene glycol monoethylether, and 754 parts of grade 280-600 aluminium oxide is applied to the fleece. The impregnated fleece is heated to 150‹C. and then 170‹C., whereby the phenolformaldehyde resin is cured and the fleece converted into a relatively rigid abrasive and polishing pad. Discs are cut from the treated fleece and tested in conventional floor polishing machines. |
