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US 8,075,831 B2Granted
Optimisation of preform preparation in injection-stretch-blow-moulding
AssigneeTotal Petrochemicals Research Feluy
InventorsEmmanuel Humbeeck, Laurent Duranel
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Abstract
This invention discloses a method for preparing a preform for two-stage injection-stretch-blow-moulding (ISBM) from polypropylene resin produced with a Ziegler-Natta catalyst system and having a melt flow index MI2 of from 1 to 20 dg/min, wherein polypropylene is injected at a melt temperature of at least 265° C. Also disclosed are the preforms obtainable by the method, the use of the preforms for preparing bottles, and the bottles prepared from the preforms.
Claims7
A method for preparing a bottle by two-stage injection- stretch-blow-moulding (ISBM) that comprises the steps of:
- a) selecting a polypropylene resin produced with a Ziegler-Natta catalyst system and having a melt flow index MI2 of from 1 to 20 dg/min, wherein the polypropylene resin is a random copolymer of propylene containing at most 6 wt % of ethylene;
- b) injecting the polypropylene resin of step a) in a mould at a melt temperature of at least 265° C. and at an injection rate of at most 20 g/s to prepare a preform;
- c) cooling the preform to room temperature;
- d) transporting the preform to the stretch-blow moulding machine;
- e) re-heating the preform in the stretch-blow moulding machine in a reflective radiant heat oven following a pre-determined temperature profile for the preform;
- f) stretching the preform axially by a centre rod and simultaneously orienting the stretched preform radially by high pressure air wherein the rod diameter is selected to be ⅔ of that of the preform.
3 more elements
Dependencies are inferred from the claim text.