Covestro Deutschland Ag

Bayer Materialscience Ag

Covestro Intellectual Property Gmbh & Co. Kg

Franky Bruynseels

Alexander Meyer

Karl-Heinz Köhler

Wolfgang Ebert

Heinz Pudleiner

Klaus Meyer

Rafael Oser

Johan Vanden Eynde

Hermann Kauth

Alexander Karbach

Ulrich Blaschke

Rolf Bachmann

Jan Heijl

Michael Roppel

Stephan Laue

Maarten De Bock

Somchai Kanjanasantisak

The invention relates to the use of branched aliphatic hydrocarbons such as squalane in compositions based on thermoplastic polymer, in particular on polycarbonate, which are used for producing molded parts used in LED lighting units, such as covers for instance. According to the invention it has been found that the use of branched aliphatic hydrocarbons makes it possible to enhance the total transmission and the transmission in the range from 360 to 460 nm, thus making corresponding compositions particularly suitable for producing molded parts for use in combination with white LED light sources. It has additionally been shown that yellowing and haze are simultaneously reduced.

Covers for LED light sources

The invention relates to aromatic polycarbonates which comprise dioxydiarylcycloalkane structural units, and which have improved optical and thermal properties. It also relates to an improved process to produce the said polycarbonates from dihydroxydiphenylcycloalkanes, and also to mixtures of these polycarbonates with polymers, with fillers, with dyes and with conventional additives.

Polycarbonate composition having improved optical and thermal properties

The invention relates to aromatic polycarbonates which comprise dioxydiarylcycloalkane structural units, and which have improved optical and thermal properties. It also relates to an improved process to produce the said polycarbonates from dihydroxydiphenylcyloalkanes, and also to mixtures of these polycarbonates with polymers, with fillers, with dyes and with conventional additives.

The invention relates to an efficient continuous method for producing polycarbonates according to the phase interface method.

Method for producing polycarbonate according to the phase interface method

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 &#x3bc;m 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 &#x3bc;m pore size at a wavelength of 400-440 nm, 25&#xd7; overall magnification and illumination time of 40 millisec. The polycarbonate is suitable for making films of improved optical properties.

Polycarbonate for making extruded films that are virtually free of surface defects

Growing community of inventors

Sint Gillis-Waas, Belgium

Franky Bruynseels