| 摘要 |
<p>In a multi-stage injection moulding process, a first moulded part functions as a moulding matrix for a second part to be moulded, in such a manner that later separation of both parts is possible. This is achieved by exchanging the mould cores after moulding and setting of the first part, and forming a moulding cavity for the second part between the first part and mould cores having a different profile. The second part is preferably moulded at a temp. below the melting point of the plastic material of the first part to prevent bonding between both parts; and a separating agent may be applied to the exposed zones of the first part. This method is particularly suitable for the manufacture of hermetically sealed, multiple container closures (sucking, bottle closure with perforated nipple, plus sealing cap). Ethylvinylacetate and polypropylene may be used in combination. The first part may be moulded with an undercut to provide mechanical connection between both parts.</p> |
