| 摘要 |
Mineral fibre prod. (I), treated with aq. soln. of a melamine-HCHO precondensate (II) etherified with a 1-4C alcohol, is used for thermal insulation of fluids heated at above 400 deg.C. Pref. (II) contains 1.5-4, partic. 2-2.5 mol. HCHO per mol. melamine. (II) is 20-100, partic. 40-75% etherified. Alcohol is MeOH. Fibres are sprayed in tunnel process with aq. soln. of (II) contg. at least 5, partic. 10-12 wt.% solids. Binder content of (I) is 2-10, partic. 3-6 wt.%. Aq. soln. also contains adhesion promoter (e.g. aminosilicone) and/or acid-liberating substance (e.g. NH4Cl). (I) has apparent density 80-120 kg/cub.m. (II) is polycondensed at 180-250 deg.C. (I) is pipe covering or shaped part. Several pipe coverings or shaped parts are arranged on top of each other so that thickness of arrangement is at least 20 cm.
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