Process for injection molding objects having at least two different layers
US5882559A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 1997 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Aug 6, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/812
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A process for the injection molding of objects having an outer layer of enamel and an inter layer of a plastic material is disclosed. According to the process, a liquid enamel is used. This enamel is injected by an enamel-injection apparatus through an enamel-injection die. A plastic melt passes through an injection unit into the cavity. According to the invention, the liquid enamel is injected into the flow path of the melt in the region before the cavity, before the melt is injected, so that the melt is encased by enamel before it is distributed in the cavity. Variations are also disclosed. For example, the form can be filled with enamel and the excess enamel drained. Then, the melted plastic material is introduced into the injection molding form. Also, the form can filled and then the capacity of the form increased to accommodate the melted plastic material. In any case, it is possible to use liquid enamels to enamel injection molded parts in the tool or form. Furthermore, the inventive process makes possible a rapid and therefore economical mode of operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.