摘要:
A process for the production of high molecular weight aliphatic polycarbonates is disclosed. The process entails a first stage wherein a low molecular weight aliphatic polycarbonate is prepared and a second stage where the low molecular weight aliphatic polycarbonate is condensed with diaryl carbonate in a melt transesterification process to form a high molecular weight aliphatic polycarbonate. The resulting high molecular weight aliphatic polycarbonate is suitable for the production of extrudates, films and molded articles.
摘要:
A phenolic compound having a branched structure is disclosed. The compound conforms to HO—Ar1—X—Ar2—[Y—W]n (1) wherein Ar1 and Ar2 independently denote an optionally substituted mononuclear or polynuclear aromatic moiety, X and Y independently denote a single bond or a divalent radical, W denotes an optionally substituted mononuclear or polynuclear aromatic moiety or an aliphatic or cycloaliphatic radical, and n is 1 to 5, is useful as a terminal group in polycarbonates, polyester carbonates and polyesters. Also disclosed is a process for producing such resins where the disclosed compound is a chain terminator.
摘要:
A process for preparing a melt transesterification catalyst is disclosed. The process entails (i) obtaining a phenol adduct of phosphonium phenolatein the form of crystalline solid and (ii) storing the solid phenol adductin a closed container at relative humidity of 30 to 70 % and at temperature of −30 to 50° C. The thus prepared catalyst is suitable in the production of polycarbonate in the melt transesterification process.
摘要:
A thermoplastic molding composition that features improved low-temperature properties and is thus suitable for application in exterior automotive parts is disclosed. The composition contains (A) 80 to 60 percent of a copolycarbonate wherein 65 to 75 mole percent of its structural units are derived from compounds of formula (I) wherein R1, R2, R3 and R4 independently of one another represents H, C1-C4-alkyl, phenyl, substituted phenyl or halogen, and wherein 25 to 35 mole percent of its structural units are derived from compounds of formula (II) where R5, R6, R7 and R8 independently one of the others denote H, CH3, Cl or Br and X is C1-C5-alkylene, C2-C5-alkylidene, C5-C6-cycloalkylene, C5-C10-cycloalkylidene and (B) 20 to 40 percent of a homopolycarbonate of bisphenol A having a melt flow rate, determined in accordance with ASTM D-1238 under 1.2 kg loading at 300° C. of 3 to 12 gm/10 minutes.