| 摘要 |
<p>An adjustable feed block for a coextrusion die is provided. The feed block comprises a main central channel for conveying a main stream of molten thermoplastic material towards a coextrusion die, and at least one secondary channel, substantially parallel to the central channel, for conveying a second molten thermoplastic intended to form a local coating layer on the main stream. The downstream end of each secondary channel is inclined relative to the central channel and connected to a portion of the periphery of the said channel. The connection between the central channel and each secondary channel is laterally delimited by the ends of two adjustable slides which can be moved at right angles to the axis of the central channel. These slides make it possible to adjust, during operation, the position and width of the streams of thermoplastic deposited on the main stream. Preferably, each secondary channel is subdivided into two curved branches which join together again upstream of the connection to the central channel, in such a way as to form an angle substantially equal to 180 DEG between them. Each secondary channel can be equipped with an adjustable distributor. The novel feed block is particularly suitable for coextrusion of profiles such as profiles for door frames or window frames.</p> |
