The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 07, 2001
Filed:
Jun. 23, 1999
BP Chemicals Limited, London, GB;
Abstract
The present invention relates to a homogeneous composition of an expandable styrene polymer in the form of beads comprising (a) 100 parts b.w. of a styrene polymer having a weight-average molecular mass of 150,000 to 300,000 and a residual monomer content of less than 2,000 ppm, (b) from 2 to 9 parts by weight of at least one blowing agent comprising n-pentane, (c) from 0.1 to less than 1.0 part by weight of a petroleum wax comprising a mixture of C,to C,alkanes, and (d) from 0 to 1.0 part by weight of a nucleating agent chosen from synthetic Fisher-Tropsch or polyolefin waxes. The composition allows the step of pre-expanding the beads to be improved by increasing the rate of expansion of the beads and by improving the productivity of the pre-expansion step, without substantially affecting the final molding step.