| 摘要 |
<p>The lawn edging (10) is formed by extruding a thermoplastic resin, preferably a thermoplastic resin such as polyethylene containing a dispersion of prevulcanized elastomer granules through a die (62) having a vertical die orifice (64) for forming the wall (12) of the channel (16). The vertical die orifice (64) also contains an element for forming protrusions (20) on a surface of the wall (12). The element preferably forms a horizontal edge on the protrusion (20). The feed rate of the element can be higher than the adjacent sections of the wall (12) such that the extruded material backs up in the die (62) and intermittently feeds through the outlet orifice (64). The channel (16) can contain a lower bead (34) and an upper hollow head member (14) which can be coated with a liquid impervious film (100) and perforated by a laser (120) to form spray apertures (122).</p> |
