Expandable beads based on a polymer of a vinylaromatic compound containing blowing agent and plasticizer
AssigneeShell Oil Company
InventorsRakesh Jaysinh Paleja, Dominique Paul Vliers, Maria Johanna Willems
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Abstract
The present invention relates to expandable beads based on a polymer of a vinylaromatic compound containing a blowing agent and, in an amount of 0.1 up to 2% wt, preferably 0.3 up to 1.5% wt calculated on the beads, of a plasticizer that is based on oligomers of styrene and/or alpha-methylstyrene having a number-average molecular weight (M.sub.n) in the range of 200 to 500, preferably of 260 to 460; and a process for preparing these expandable beads.
Claims8
Expandable beads comprising a polymer of a vinylaromatic compound containing a blowing agent and, in an amount of 0.1 up to 2% wt, calculated on the beads, of a plasticizer comprising oligomers of styrene and/or alpha-methylstyrene, the oligomers of styrene and/or alpha-methylstyrene having a number-average molecular weight (M.sub.n) in the range of 260 to 460.
A process for preparing expandable beads comprising the steps of:
- polymerizing a vinylaromatic monomer in aqueous suspension in the presence of a plasticizer, the plasticizer comprising oligomers of styrene and/or alpha-methylstyrene, the oligomers of styrene and/or alpha-methylstyrene having a number-average molecular weight (M.sub.n) in the range of 260 to 460;
- and
- adding the blowing agent thereto before, during and/or after the polymerization.
Dependencies are inferred from the claim text.