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Basf Magnetics Gmbh

Klaus D Schomann

Sibylle Brosius

Harald Kuppelmaier

Michael Schmitt

Peter Neumann

Bernhard Albert

Wolfgang Schrott

Michael Acker

Helmut Barzynski

Wulf Muenzner

Roland Roos

Werner Balz

Heinz Berger

Gerhard Wagenblast

Hartmut Hibst

Harald Keller

Helmut Steininger

Gerhard Rotter

Helmut Kopke

Karl-Heinz Feuerherd

Matthias Dust

Ulrich Jaeger

Arend Werner

Peter Hauser

Peter Hammerschmitt

Heidi Benthack-Thoms

Hans-Peter Schildberg

Harald Kuppelhamier

Ulrich Harten

Mathias Dust

Kal-Heinz Feuerherd

Carbonyloxy-substituted azulenesquaric acid dyes of the formula ##STR1## where L is C.sub.1 -C.sub.12 -alkylene which may be substituted by phenyl,

Carbonyloxy-substituted azulenesquaric acid dyes, intermediates therefor

A magnetic recording medium comprises a nonmagnetic substrate and at least one ferromagnetic metal layer applied thereon and a protective layer formed on this metal layer and consisting of a compound which consists of an unfluorinated or partially fluorinated alkyl radical and a disulfide, hydroxyl or keto group.

Magnetic recording medium

Moving laser beams from useful tracks to alternative positions in devices in which information is stored optically or magneto-optically. This results in higher signal-to-noise ratios.

Repositioning laser beams in information storage media

Polymethine dyes suitable for use in an optical recording medium have the formula ##STR1## where p is 0 or 1,

Heterocyclic polymethine dyes with carbamate or amide groups

Binary azulenesquaric acid dyes of the formula ##STR1## where X is a bridging member, Y is hydrogen, cyano or formula CO--OR.sup.5, CO--NHR.sup.5, OR.sup.5, O--CO--OR.sup.5, NH--CO--R.sup.5, NH--CO--OR.sup.5 or NH--SO.sub.2 --R.sup.5, where R.sup.5 is hydrogen, C.sub.1 -C.sub.12 -alkyl, C.sub.2 -C.sub.12 -alkenyl, C.sub.5 -C.sub.7 -cycloalkyl or unsubstituted or substituted phenyl, L.sup.1 and L.sup.2 are each, independently of one another, a chemical bond or unsubstituted or substituted C.sub.1 -C.sub.12 -alkylene and R.sup.1, R.sup.2, R.sup.3, R.sup.4, Q.sup.1, Q.sup.2, Q.sup.3 and Q.sup.4 are each, independently of one another, hydrogen or unsubstituted or substituted C.sub.1 -C.sub.12 -alkyl, their intermediates and an optical recording medium containing the novel dyes are described.

Binary azulenesquaric acid dyes, their intermediates and optical

An optical recording medium consists essentially of a base material and a light-absorbing layer which contains a thermoplastic binder and at least one dye, wherein the thermoplastic binder is a polycyclic hydrocarbon which has a glass transition temperature Tg of greater than 150.degree. C. and is soluble to more than 3% by weight in an aliphatic or aromatic hydrocarbon.

Optical recording medium

Amido-containing azulene-aquaric acid dyes of the formula ##STR1## where L is C.sub.1 -C.sub.12 -alkylene which may be substituted by phenyl,

Amido-containing azulene squaric acid dyes, intermediates therefor and

Methine dyes of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, X, Y and the rings A and B each have specific meanings, and methine dyes obtainable by reacting an organic mono- or polyisocyanate with such a methine dye of the abovementioned formal where only the radicals R.sup.1 and/and R.sup.4 have a group reacting with an organic mono- or polyisocyanate are useful in optical recording media.

Methine dyes and optical recording medium containing same

Azulenesquaric acid dyes of the formula ##STR1## where L is substituted or unsubstituted C.sub.1 -C.sub.12 - alkylene,

A zulenes containing a urethane group

Azulenesquaric acid dyes of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 each have specified meanings are prepared from azulene derivatives of the formula ##STR2## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 each have specified meanings as intermediates, and used in an optical recording medium.

Azulenesquaric acid dyes, azulene intermediates therefor, and optical

Quinoxalinepentamethine dyes of the formula ##STR1## where R.sup.1 is hydrogen, substituted or unsubstituted C.sub.1 -C.sub.22 -alkyl or substituted or unsubstituted C.sub.5 -C.sub.7 -cycloalkyl,

Quinoxalinepentamethine dyes and optical recording medium containing same

Azulenesquaric acid dyes of the formula ##STR1## where L is substituted or unsubstituted C.sub.1 -C.sub.12 -alkylene,

Azulenesquaric acid dyes that contain urethane groups

An optical recording medium comprises a support material and a light-absorbing layer consisting essentially of a soluble mixture of a thermoplastic binder and at least one dye, wherein the thermoplastic binder is a phenol-aldehyde resin having an average molecular weight of greater than 300 which is soluble in an alcohol having a boiling point of less than 200.degree. C.

Naphtholactamsquaric acid dyes of the formula ##STR1## where R.sup.1 and R.sup.2 independently of one another are each unsubstituted or substituted C.sub.3 -C.sub.22 -alkyl, in which the alkyl chain may be interrupted by oxygen atoms, or are each unsubstituted or substituted C.sub.1 -C.sub.4 -aralkyl, unsubstituted or substituted C.sub.5 -C.sub.7 -cycloalkyl or unsubsituted or substituted phenyl, and the rings A, B, C and D are unsubstituted or substituted and/or benzofused, and optical recording materials consisting of a base and a layer which is sensitive to laser light and is composed of a thermoplastic or crosslinked polymer and one or more dyes (I). Because of the high light absorption of (I), the recording materials are very sensitive to light from the GaAlAs semiconductor laser. An excellent signal-to-noise ratio is obtained on reading the recordings.

Naphtholactamsquaric acid dyes and optical recording materials

A tape guide system wherein a magnetic tape having different resistivities on its back and front travels in contact with guide elements, the members of these elements which are in contact with the tape being matched to the relevant face of the tape in respect of surface resistivity and/or of charge affinity. The members contacting the front of the magnetic tape accordingly consist of a conductive or low-insulation material and the members contacting the back of the tape consist of a high-insulation material. In alternative embodiments, the contact members can consist of a material of low conductivity, or of a plastic with an added conductive material. The novel guide system can be used in any type of high-speed magnetic tape transport mechanism. The invention also concerns the tape guide elements per se, and magnetic tape cassettes employing the tape guide system.

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Ludwigshafen, Germany

Klaus D Schomann