Roehm Gmbh Chemische Fabrik

Rohm Gmbh Chemische Fabrik

Roehm Gmbh & Co Kg

Basf Aktiengesellschaft

Hans Lorenz

Michael Meier-Kaiser

Volker Benz

Michael Mueller

Heinz Gross

Martin Berkenkopf

Udo Fischer

Helmut Haring

Werner Siol

Gerhard Heinz

Uwe Numrich

Eckhard M Koch

Markus Parusel

Wolfgang Eberle

Hermann Buchert

Jann Schmidt

Norbert Brand

Christoph Krohmer

Herbert Groothues

Wolfgang Scharnke

Karl Funk

Guenther Dickhaut-Bayer

Volker Mende

Klaus Hofmann

Helmut Haering

Peter R Szigeti

Berthold Schoenig

Michael M&uuml;ller

Klaus Koralweski

Klaus-Ernst P&ouml;hlmann

Klaus-Ernst Poehlmann

Roland Schuchmann

Uwe Jacobsen

Otto Diroll

Gunther Schreyer

A rear-projection screen that has at least one light-scattering polymethyl methacrylate layer in which is embedded spherical plastic particles; the previously described rear-project screen that has an additional plastic sheet that does not have embedded scattering beads; and a method of making a rear-projection screen.

Rear projection screen and method for the production thereof

The invention relates to a solid body of plastic, glass, ceramic or metal which has at least partially a microstructured surface with rows oriented in a preferential direction of cross-sectionally trapezoidal or wedge-shaped ridges, wherein the ridges have minima and maxima in height (H) which lie in the range from 0 mm to 2 mm, and the minima and maxima follow one another periodically with amplitudes in the range from 0.005 to 20 mm, and the spacing of the rows of neighboring ridges in relation to one another is 0.002 mm to 5 mm, it being possible for the valleys between the rows to be planar, curved or tapered, and the cross-sectionally trapezoidal or wedge-shaped ridges have a wedge angle (&#x3b1;) in the range from 15 to 75&#xb0;.

Solid body with microstructured surface

Multilayer plastic composites containing at least two incompatible plastics, A and B, in which the layering sequence alternates between A and B, the layers of plastic B are discontinued at regular intervals, and the resulting gaps in the layers are filled in with plastic A, exhibit good adhesion between the layers. In preferred embodiments of the invention, the amorphous, crystalline, or semi-crystalline plastic B has a higher coefficient of thermal expansion than the amorphous plastic A. The plastic composite is preferably produced via coextrusion.

Plastic composites made from incompatible plastics

The invention relates to optical diffuser plates (1) made of transparent plastics such as polycarbonate or polymethacrylate. Several thin strips (2) made of plastic B inserted into plates made of transparent plastic A with the proviso that A and B are incompatible and the strips (2) made of plastic B are subsequently withdrawn. The hollows that are formed in the plate (1) made of plastic A are used to deflect light.

Optical diffuser plates

Process for preparing multilayer plastic composites of incompatible plastics

A process for the extrusion of plastic plates with very finely structured surface using an extrusion system which is equipped with an extruder and a three roll polishing stack containing a roller with the structuring surface. The system is designed for coextrusion and the plastic plates are produced via two extruders as a coextrudate CX from a highly viscous basic molding compound BF and a low viscosity molding compound NF which is extruded on BF. The surface of said plates is structured via the three roll polishing stack. Fresnel lenses produced by the process may be used in solar collectors.

Process for manufacture of fresnel lenses

Process for manufacture of Fresnel lenses

The invention relates to transparent composite plate systems of a) at least two acrylic glass exterior plates S, S' with a thickness of at least 2 mm and parallel surfaces, and b) an intermediate layer Z containing a thermoplastically processable elastomer E, whereby the elastomer E contains from 60-100% by weight of a comb polymer KP, which itself contains from 50 to 5% by weight of at least one polymethyl methacrylate macromonomer of Formula I ##STR1## and from 95 to 50% by weight of alkyl acrylates of Formula II ##STR2## wherein R and R.sub.4 are defined in the claims.

Transparent composite plate system

A flat web of sizable thickness made of thermoplastic can be extruded from an extrusion die without a restrictor bar if a thickness D of a restricting passage is made smaller than a shaping distance A of die lips (4, 5), and if at least one wall of the restricting passage (6) is adjustably designed as an elastic lip (7) by adjusting elements (8), so that thickness D and distance A can be changed at the same time by actuating the adjusting elements.

Extrusion die for thermoplastic webs

Thermoplastically re-formable plastic sheets with flameproofing means, characterized by a core layer 1-10 mm thick comprised of polyether sulfone or a similar thermoplastic, which core material has a content of at least 0.5 wt. %, preferably at least 2 wt. %, of a flame-protective additive, such as boron trioxide; and said sheet or plate further characterized by outer layers, firmly adhering to and covering the two faces of the core layer, at least 0.05 mm thick and comprised of a thermoplastic having a lower proportional content of the flame-protective additives than the core layer; are particularly useful for interior structures in passenger conveyances, such as airplanes.

Plastic sheet or plate with flameproofing means

For producing a multi-extrudate of thermoplastically processable plastic, a coextrusion adapter block has a multi-part slide having a plurality of side-by-side slide sections mutually spaced in a direction transverse to the flow direction and slidably fitted in the adapter block for movement to adjustably protrude into a secondary runner for adjusting the thickness of a molten extrudate therein. A multi-layer extrudate emerging from the adapter block is further extruded in an extrusion die, and the thickness of at least one layer thereof is measured at a plurality of positions along the width thereof. The width measurements are used to control the positions of corresponding slide sections so that the layer thicknesses can be accurately controlled during an extruding operation.

Process and system for producing multi-layer extrudate

An extrusion die slot for extruding flat thermoplastic webs has a plurality of plates mounted to the flexible lip of the die body. A regulating force from a control element is applied to the plates, and so to the flexible lip, via the flexible strip pressed between the control element and the plates.

Extrusion slot die with flexible lip

Growing community of inventors

Darmstadt, Germany

Hans Lorenz