Total Research & Technology Feluy

Totalenergies Onetech Belgium

Michel Cassart

Francis Couget

Elena Prats

Jacques Michel

Laetitia Urbanczyk

Jean-Claude Deleye

Magali Vachaudez

Amelio Iacolina

The present invention is related to expandable vinyl aromatic polymers comprising comminuted coke, said comminuted coke having an average stack height (Lc) of carbon crystallites at least 4 nm, a volume median particle diameter (D50) comprised between 1 and less than 5 &#x3bc;m and being characterized by a span (D90&#x2212;D10)/D50 below 2.5 Molded parts produced from the expandable vinyl aromatic polymers prove low thermal conductivities for a low foam density.

Expandable vinyl aromatic polymers

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).

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

Growing community of inventors

Braine-l'Alleud, Belgium

Michel Cassart