| 摘要 |
<p>Cellular filler based on polyurethane (urea) for longitudinal sealing of electrical or optical communications cables with plastics-insulated carrier elements and/or corresp. cable fittings is produced by adding much less water than is usual in polyurethane foam mfr. for the isocyanate-water reaction, i.e. max. twice as much as is needed theoretically to produce the required degree of foaming, and partially replacing part of the organic OH cpds. (polyester-polyols, polyether-polyols or polyester-polyether-polyols with equiv. wts. of ca. 100-500) required for the normal polyurethane reaction with cpds. (I) acting as chain inhibitor and internal plasticiser. The filler is not detrimental to flexibility of the cable. Pref. (I) consists of long-chain, aliphatic, branched, monohydric alcohols with an equiv. ratio of 10-50% w.r.t. OH cpds. used; di- or poly-hydroxyl cpds. with equiv. wts. of 800-1600; or isocyanate prepolymers with NCO content of 5-15%.</p> |
