| 摘要 |
A warp knit weft insertion fabric has a plurality of warp yarns and weft insertion yarns of a denier of at least about 1000, each of which yarns is separated from its neighbors by a plurality of yarns of a lower denier of about 220 to about 1800, the ratio of denier of the heavier yarn to lighter yarn being about 1.5 to about 6:1. The arrangement of yarns in both warp and weft is optionally symmetrical, i.e. there are the same number of yarns per inch and the same number and denier of the lighter weight yarns separating the same number and denier of the heavier yarns in both directions. In a particular feature of the invention the yarns in one or both directions are formed in situ by feeding two or more yarns of lower denier in tandem during the knitting process to form a single yarn of higher denier in the finished fabric. The fabric is employed as a reinforcement for sheet material of thermoplastic synthetic resin (by lamination or coating techniques and the like). The reinforced sheet material so produced has a markedly higher ratio of tear strength to tensile strength than similar reinforced sheet materials hitherto available and is useful in a wide variety of industrial applications including fabrication of mine brattice, mine ventilation tubing and the like.
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