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Thermoplastic, branched aromatic polyphosphonates, and a process for their production

  • US 4,415,719 A
  • Filed: 12/07/1981
  • Issued: 11/15/1983
  • Est. Priority Date: 06/22/1979
  • Status: Expired due to Fees
First Claim
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1. A process for the production of a thermoplastic branched, aromatic polyphosphonate having a number average molecular weight of above 11,000 said process comprising transesterifying components (a) and (b) with (c) and (d) wherein component (a) is from 97 to 100 moles of at least one diaryl phosphonate and component (b) is up to 3 moles of at least one triaryl phosphate with the sum of the moles of (a) and (b) being 100, component (c) is from 90 to 99 moles of at least one aromatic dihydroxy compound and component (d) is up to 3 moles of at least one aromatic trihydroxy or tetrahydroxy compound with the proviso that at least one of the components (b) and (d) is present in a quantity of at least 0.001 mole and that the combined amount of (b) and (d) is at most 3 moles;

  • said transesterification being conducted in the melt at 90°

    C. to 340°

    C. in an oxygen-free atmosphere at atmospheric pressure or lower and in the presence of from 10-5 to 5×

    10-2 mole percent, based on 100 mole percent of aromatic dihydroxy compound, of at least one basic catalyst, with the volatile constituents produced in the course of transesterification being removed by distillation.

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