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Process for preparing polycarbonates by self-condensation of bisphenol dichloroformate

  • US 3,312,660 A
  • Filed: 07/03/1962
  • Issued: 04/04/1967
  • Est. Priority Date: 07/03/1962
  • Status: Expired due to Term
First Claim
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1. THE PROCESS FOR PREPARING A POLYCARBONATE RESIN WHICH COMPRISES SELF-CONDENSING AT ELEVATED TEMPERATURES OF BETWEEN ABOUT 60*C. TO 250*C. AN ANHYDROUS MIXTURE OF A BISPHENOL DICHLOROFORMATE IN THE PRESENCE OF ABOUT A STOICHIOMETRIC QUANTITY OF A METAL SALT AS THE SOLE REACTIVE MATERIALS IN THE REACTION, SAID METAL SALT BEING ONE IN WHICH THE CATION IS A METALION IN ITS HIGHEST VALENCE STATE SELECTED FROM GROUPS I-A, II-A, AND II-B OF THE DEMING PERIODIC SYSTEM OF ELEMENTS AND THE ANION IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF CO3--, HCO3-, SO3--, AND HSO3-.

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