Total Research & Technology Feluy

Francis Couget

Michel Cassart

Elena Prats

The present invention is a method to start-up a process to make expandable vinyl aromatic polymer pellets comprising, In another embodiment while the pelletizer (S) is in production and troubles happen in the introduction of the expanding agent and/or the optional additives or in any equipment or even an equipment needs maintenance the production is switched from the pelletizer (S) to one or more pelletizers (L). When the troubles are over, the production is switched from the pelletizer (L) to the pelletizer (S). In an embodiment while the pelletizer (S) is in production the die plate of the pelletizer (L) having a plurality of holes of large diameter is removed and replaced by a die plate having a plurality of holes of small diameter to convert said pelletizer (L) into a pelletizer (S) capable to produce expandable vinyl aromatic polymer pellets. By way of example said established pelletizer (S) is used during maintenance of the other pelletizer (S).

Method to start-up a process to make non-expandable vinyl aromatic polymers

A method for producing expandable pellets can include introducing a vinyl aromatic polymer and an expandable agent to a pelletizer (L). The pelletizer (L) can have a die plate having a holes of large diameter. During the start-up of the production of the expandable pellets, pellets can be produced in the pelletizer (L). When the polymer flow rate is in the operating range of the pelletizer (S), the introduction of the vinyl aromatic polymer and the expandable agent can be switched from the pelletizer (L) to the pelletizer (S). The pelletizer (S) can be operated at conditions effective to produce the expandable pellets. The pelletizer (S) can have a die plate having holes of small diameter. The expandable pellets can be recovered from the pelletizer (S), and the pellets can be recovered from the pelletizer (L).

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Stiring-Wendel, France

Francis Couget