Abstract: 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 ?m and being characterized by a span (D90?D10)/D50 below 2.5 Molded parts produced from the expandable vinyl aromatic polymers prove low thermal conductivities for a low foam density.

Abstract: 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 less than 4 nm, a volume median particle diameter (D50) comprised between 0.8 and 4 ?m and being characterized by a span (D90?D10)/D50 below 2.5. Molded parts produced from the expandable vinyl aromatic polymers prove low thermal conductivities for a low foam density.

Abstract: 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 ?m and being characterized by a span (D90?D10)/D50 below 2.5 Molded parts produced from the expandable vinyl aromatic polymers prove low thermal conductivities for a low foam density.

Abstract: The present invention is related to expandable vinyl aromatic polymers comprising from 1 to 10% by weight of homogeneously dispersed coke particles having a volume median particle diameter (D50) comprised between 0.5 and 8.5 ?m and from 0.1 to 5% by weight of a halogenated block copolymer. The invention further is related to a method for producing said expandable vinyl aromatic polymers and to the expanded foams.

Abstract: The present invention is a method to start-up a process to make expandable vinyl aromatic polymer pellets comprising, a) providing a pelletizer (S) containing means to introduce the molten vinyl aromatic polymer comprising the expandable agent and optionally additives, a die plate having a plurality of holes of small diameter, typically in the range 0.8 to 1.

Abstract: A method for producing non-expandable pellets can include introducing a vinyl aromatic polymer 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 non-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 can be switched from the pelletizer (L) to the pelletizer (S). The pelletizer (S) can be operated at conditions effective to produce the non-expandable pellets. The pelletizer (S) can have a die plate having holes of small diameter. The non-expandable pellets can be recovered from the pelletizer (S), and the pellets can be recovered from the pelletizer (L).

Abstract: 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).

Abstract: The present invention is a method to start-up a process to make expandable vinyl aromatic polymer pellets comprising, a) providing a pelletizer (S) containing means to introduce the molten vinyl aromatic polymer comprising the expandable agent and optionally additives, a die plate having a plurality of holes of small diameter, typically in the range 0.8 to 1.