| 摘要 |
<p>A method of injection molding a multi-layer preform from a combination of virgin and recycled plastic such as PET so that the resultant blow-molded bottle has a reduced tendency for bottom failure in spite of the use of recycled plastic. A first plastic preform (20) for providing the inner layer of the multi-layer preform is provided with spaced channels (C1-C4) on the exterior surface of a closed end (20E) thereof extending from a central region of that end to the sidewalls. An injection mold cavity is provided with a like plurality of channels (C1'-C4') formed therein in a closed end (12A') thereof communicating with the injection gate (22') of an injection molding apparatus. The first plastic preform (20) is inserted into the injection mold cavity with the respective channels (C1-C4, C1'-C4') of the preform and the injection mold cavity substantially aligned. A second layer (30) of plastic material is overmolded onto the first layer (20) by injection molding in the cavity. A third layer (40) of plastic material may be overmolded on the second layer (30) to form a three-layer preform. Preferably the first and third layers (20, 40) are formed from virgin plastic and the second layer (30) is formed from recycled plastic.</p> |
