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AssigneeHoechst Aktiengesellschaft
InventorsJosef Geirhos, Ingolf Jacob
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There is described an intermingled multifilament yarn comprising high modulus monofilaments made for example of aramid, carbon or glass and a process for producing this yarn. Conventional air intermingling is impracticable for high modulus yarns since they tend to break, because of their brittleness, which leads in particular to an appreciable reduction in the tenacity. The invention proposes carrying out the intermingling at elevated temperature--either by preheating the yarn or by heating the intermingling air. It is found, surprisingly, that, although the entanglement spacings are relatively low, the tenacity remains substantially unaffected and in some instances is even raised. The multifilament yarn produced by this process is noteworthy in particular for the low number of broken monofilament ends. The invention can also be applied to commingled yarns, yarns which are part high modulus filaments and part thermoplastic filaments.
A process for producing a multifilament yarn having a total linear density of 500-4000 dtex and consisting at least in part of high modulus monofilaments having an initial modulus of more than 50 GPa in which individual filaments of the multifilament yarn are intermingled with one another by subjecting the filaments to an intermingling medium, carrying out intermingling of the individual filaments with one another at an intermingling temperature of 0.25-0.9 T.sub.m where T.sub.m is the melting point or decomposition temperature of the high modulus monofilaments measured in .degree. C. and wherein the yarn is intermingled to such an extent that an average entanglement spacing of the yarn, measured in a pin court test, is less than 150 mm.
Dependencies are inferred from the claim text.