Invention Grant
- Patent Title: Double bubble process for making strong, thin film
- Patent Title (中): 双层气泡制作强力薄膜
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Application No.: US409281Application Date: 1995-03-23
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Publication No.: US5674608APublication Date: 1997-10-07
- Inventor: Henry G. Schirmer
- Applicant: Henry G. Schirmer
- Applicant Address: SC Duncan
- Assignee: W. R. Grace & Co.-Conn.
- Current Assignee: W. R. Grace & Co.-Conn.
- Current Assignee Address: SC Duncan
- Main IPC: B29C55/28
- IPC: B29C55/28 ; B32B27/32 ; B32B27/36 ; B32B27/00
Abstract:
Polymeric, thin oriented films can be made by use of a combination of a hot blown process and a blown bubble process, i.e. a double bubble process. The resulting film has use in replacing PVC for in store stretch wrap applications. Very low density polyethylene, VLDPE, is an especially preferred material for this process. It may be used as a monolayer, or as one layer of a multilayer structure. In practicing the invention, the polymer is extruded and hot blown, and heated to a temperature above its orientation temperature. This heating can be accomplished by the use of a heated liquid reservoir or sock disposed at the lower end of the primary bubble, inside the bubble. The hot blown heated film is then passed through a first set of pinch rolls, re-inflated into a blown bubble, and collapsed at a second set of pinch rolls. Thin, tough and elastic packaging materials are obtained by this process.
Public/Granted literature
- US4976751A Method for purification of exhaust air Public/Granted day:1990-12-11
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