| 摘要 |
The process of this invention will involve overmolding a thermoplastic or rubbery polymer composition over a thermoplastic hollow tube and a core insert to form a hollow overmolded coupler after the removal of the core insert, the tube entering the coupler at an angle which is less than 90 DEG so as to minimize any freezing of transported water which may reside in the coupler. The combination of the above polymers must satisfy at least two simultaneous conditions. First, the inserted plastic tube must not soften and begin melt flow to the point where it looses structural integrity during the molding processing and second, the overmolded polymer must be capable of forming an essentially leak-proof interface between the coupler and the plastic tube, preferably through either a chemical and/or physical bond between the plastic tube and the overmolded plastic. In one aspect of the invention, the composition of the overmolded polymer will be such that it will be capable of at least some melt fusion with the composition of the plastic tube, thereby maximizing the leak-proof characteristics of the interface between the plastic tube and overmolded plastic, e.g., by having at least a component of the polymer composition of the plastic tube and that of the overmolded polymer being the same or at least sufficiently similar or compatible so as to permit the melt fusion or blending or alloying to occur at least in the interfacial region between the exterior of the plastic tube and the interior region of the overmolded polymer.
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