Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
  • C08K5/098—Metal salts of carboxylic acids

Definitions

• the present invention provides for a novel method for affecting the optical clarity of polycarbonate resin which has been prepared via the transesterification of a diaryl carbonate and a dihydric phenol, which involves adding to the polycarbonate resin a minor but effective amount of a lithium compound nucleating agent.
• polyarylates may be prepared by transesterification and polycondensation of mixtures of diaryl esters of aromatic carboxylic acids, together with diaryl carbonate, if desired, and dihydric phenols, and that polycarbonates may be prepared by transesterification of a diaryl carbonate with a dihydric phenol.
• polyarylates are considered to be polycarbonates in which all or part of the carbonic acid residues are replaced by aryl dicarboxylic acid residues, preferably isophthalic and/or terephthalic acid residues.
• a transesterified polycarbonate resin employable for purposes of this invention, is suitably prepared by blending e.g. , diphenyl carbonate and bisphenol-A as a melt in the presence of an appropriate catalyst.
• the molecular weight of the resulting resin is preferably in the range between 8,000 to 100,000, preferably 10,000 to 80,000, and exhibits an intrinsic viscosity between 0.4 to 0.7 dl/g.
• the reaction components are passed through a number of stages involving melting the reaction components, reacting the componen.ts, pre-polymerizing the reaction product and, finally, polymerizing the effluent from the pre-polymerization stage in a final polymerization stage.
• a new method for the transesterification of a diaryl carbonate and a dihydric phenol which allows for shorter residence time in the pre-polymerization stage of the reaction process , and thus produces an enhanced yield of reaction product in less ime, comprises using a series of equipment including a melter, a reactor, a pre-polymeriza ⁇ tion reactor and then more polymerization reaction vessels.
• non-ferrous reaction vessel components such as, nickel, titanium, chromium metals or the like for all contact surfaces, in such a system, such as for pipings, reactor, and/or recovering vessels, etc., clad or lined with such materials or with glass , provides a superior system for producing polycarbonate resin vis the transesterification reaction, since the resultant product will be free from undesirable color formation.
• lithium salts In carrying out the transesterification of diphenyl carbonate and bisphenol-A to produce a bisphenol-A polycarbonate, with the removal of phenol, various lithium salts are known to have utility as catalysts for the reaction. Typically, lithium salts such as the various lithium halides and lithium hydroxides have been employed for this purpose. It has been found, however, that the effectiveness of the lithium salts which are conventionally employed for carrying out the transesterification of bisphenol-A and diphenyl carbonate is limited by the fact that such salts are only partially soluble in the reaction medium.
• the polycarbonate resins produced via the transesterifica ⁇ tion of a diaryl carbonate and a dihydric phenol find utility in the production of various films and similar materials, wherein controlled crystallization of the resinous materials is effected via known techniques. Control by crystallinity is important in achieving optical clarity and the best impact properties in films and thicker molded articles.
• the present invention provides for a beneficial method for promoting and enhancing the controlled crystallization of polycarbonate resins produced via the transesterification of a diaryl carbonate and a dihydric phenol which allows for the production of sheet and film material having improved characteristics over those produced using prior art methods. . It is based on the addition of lithium compounds in very small amounts to transesterified polycarbonates.
• a method for promoting and enhancing the crystallization, optical clarity and impact resistance of polycarbonate resins prepared by the transesterification of a diaryl carbonate and a dihydric phenol comprising adding to the polycarbonate resin a minor but effective amount of a lithium compound nucleating agent, said nucleating agent being selected from inorganic lithium compounds and organic lithium compounds such as lithium stearate, and allowing the composition to crystallize, to a desired degree of crystallinity at a controllable crystallization rate.
• crystallized transparent and higher strength transesterified polycarbonate films can be readily and efficiently produced by casting, extruding or compressing the pre-crystallized pellets.
• diphenyl carbonate and bisphenol-A are used in the transesterification reaction, although, it is under- stood that the present invention contemplates polycarbonate resins prepared from other dihydric phenols and diaryl carbonates well-known in this art.
• the lithium compound nucleating agent employed in the herein disclosed method can be.an inorganic material or it can be of the organic type. Suitable examples of organic lithium compound is preferably a lithium acylate in which the acyl group is derived from an organic acid containing from 6 to 25 carbon atoms, most preferably lithium stearate.
• the nucleating agent described above is added in amounts of from about 4 to about 16 ppm, preferably 10 to 14 ppm, based on the total weight of the composition.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyesters Or Polycarbonates (AREA)

Priority Applications (2)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22175169

Family Applications (1)

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Citations (11)

• 1983
  • 1983-05-23 JP JP50216783A patent/JPS60501412A/ja active Granted
  • 1983-05-23 WO PCT/US1983/000788 patent/WO1984004750A1/en unknown

Patent Citations (11)

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