Bayer Materialscience Ag

Bayer Intellectual Property Gmbh

Raymond Wong

Friedrich-Karl Bruder

Wilfried Haese

Rafael Oser

Ice Zhang

Wolfgang Fischer

Alexander Meyer

Michael Ludewig

Karlheinz Hildenbrand

Ulrich Blaschke

Rainer Protte

Michael Roppel

Jörg Wehrle

Oser Rafael

This invention relates to DVDs made from polycarbonate and a special UV curable bonder material consisting of A) an urethane acrylate oligomer as binder, which is the reaction product of i) one or more polyisocyanates and ii) one or more hydroxyfunctional lactone ester (meth)acrylates having a number average molecular weight of from 200 g/mol to 2000 g/mol and having the formula: CH&#x2550;C(R)&#x2014;C(O)&#x2014;O&#x2014;R&#x2014;[O&#x2014;C(O)&#x2014;R]&#x2014;OH wherein, n is an integer from 1 to 5, Ris hydrogen or methyl, Rrepresents an alkylene group or substituted alkylene group having from 2 to 10 carbon atoms and Rrepresents a straight or branched chain alkylene group of from 3 to 8 carbon atoms, and which may be substituted with one or more alkyl groups having from 1 to 12 carbon atoms, B) a reactive thinner, comprising of mono functional acrylates and/or (meth)acrylates C) a photo initiator and D) optional additives which offers improved performance at high data transfer rates.

High speed DVDs

This invention relates to an optical recording medium in which at least a recording layer and a light transmitting layer are sequentially formed on a substrate and in which the light is illuminated from the light transmitting layer side for recording and/or reproducing information signals, said substrate comprising an injection molded part, and said substrate having a Young's modulus E of at least 2.15 GPa and a Q factor of lower than 160 measured at 25&#xb0; C. at 2000 Hz in accordance to ASTM E 756-05 05 and a transcriptability of the pit/groove structure of &#x3e;85%.

Disc shaped high density recording medium

This invention relates to the use of polycarbonate for the production of an optical recording medium in which secure high speed operation, a transcriptability of the pit/groove structure of &#x3e;85% and sufficient disc flatness can be achieved and the polycarbonate is based on bisphenol A and the polycarbonate contains a release agent in an amount less than 2000 ppm.

Substrate material for high speed optical discs

Growing community of inventors

Hong Kong, China

Raymond Wong