摘要:
Aromatic and aliphatic-aromatic carbonic acid diesters can be obtained by transesterification of carbonic acid diesters containing aliphatic ester groups if polymeric hydroxystannoxanes are employed as catalysts.
摘要:
The invention relates to a process for the preparation of optionally branched, high molecular weight polyarylene sulphides with melt viscosities which can be established within a defined range and low corrosion.These polyarylene sulphides have been obtained by reacting alkali metal sulphides, if appropriate mixed with alkali metal bisulphides and reaction accelerators, with dihalogenoaromatics and polyhalogenoaromatics, with the addition of monohalogen and monomercapto compounds.
摘要:
Linear polycarbonate resin virtually free of surface defects that impair the suitability of the resin for demanding optical application is disclosed. Also disclosed is a process for the manufacture of the resin. The surface defects included in the resin are in the form of transparent fluorescing particles, the particle count of which portion that are 15 and 250 μm in size, is up to 1.8 counts/g, said count being determined by exciting the residue remaining after filtering a solution of said polycarbonate in methylene chloride through a Teflon filter of 5 μm pore size at a wavelength of 400-440 nm, 25× overall magnification and illumination time of 40 millisec. The polycarbonate is suitable for making films of improved optical properties.
摘要:
The present invention relates to polycarbonate, polyester carbonate and polyester having end groups derived from alkylsiloxane-substituted phenols, as well as to the use of phenolic compounds having alkylsiloxane substituents as chain terminators in the preparation of polycarbonate, polyester carbonate and polyester, as well as to mouldings and extrudates produced from these polymers, to processes for the preparation of the polymers, and to novel phenolic compounds of formula (2).
摘要:
Continuous processes for preparing polycarbonates having a weight average molecular weight MW, of 15,000 to 200,000 g/mol, the processes comprising reacting a dihydroxydiarylalkane and phosgene in the presence of a catalyst in a phase boundary process comprising: continuously dispersing in a disperser an organic phase comprising at least a portion of the phosgene and a solvent suitable for the polycarbonate and an aqueous phase comprising the dihydroxydiarylalkane, water and an alkali solution present in an amount of 1.5 to 2.5 moles per mole of the dihydroxydiarylalkane, to form a mixture; reacting the mixture in a first reactor with a residence time of less than 0.5 seconds; further reacting the mixture in a second reactor with addition of further alkali solution and, optionally, a chain terminator; and effecting further condensation in a third reactor with addition of further alkali solution and, optionally, a chain terminator, in the presence of the catalyst.
摘要:
A process for treating the working surfaces of equipment used in the production and processing of polycarbonate is disclosed. The thermal treatment in an oxidative atmosphere results in resin and molded articles having improved optical quality.
摘要:
A thermoplastic composition having improved rheological and optical properties containing aromatic polycarbonate and an oligomeric epoxy resin is disclosed. The epoxy resin that conforms to formula (I) wherein R1, R2 mutually independently denote H, C1-C12 alkyl, cyclic C5-C12 alkyl, phenyl or benzyl groups and n is an integer of 0 to 20, contains no more than 0.1% water. A process for purifying the epoxy is also disclosed
摘要:
A polycarbonate resin that after alkaline hydrolysis with sodium hydroxide contain an amount of 0.01 to 150 ppm of carbamate compounds according to formula (1) wherein R1 and R2 independently of one another denote hydrogen or C1-C12-alkyl, or together denote C4-C12-alkylidene, and R3 and R4 independently of one another denote hydrogen, C1-C12-alkyl or phenyl, or together with the carbon atom to which they are bonded form cyclohexyl or trimethylcyclohexyl, said amount measured after alkaline hydrolysis with sodium hydroxide by high pressure liquid chromatography.
摘要:
Optical fibers suitable for transmission of optical signals and comprising a core that contains polycarbonate are disclosed. The polycarbonate is characterized in its low content of insoluble particles.
摘要:
The invention relates to new, monomeric, perfluoroalkyl-substituted metal complexes, processes for their production, and their use in diagnosis and therapy.The compounds according to the invention are suitable especially as in vivo contrast media in nuclear spin tomography (MRT). They can preferably be used as blood-pool agents and as lymphographic agents.