Rohm Gmbh

Roehm Gmbh & Co Kg

Evonik Rohm Gmbh

Leonhard Maier

Hermann Seibert

Werner Geyer

Wolfgang Pip

Thomas Barthel

Torsten Jahn

Dirk Roosen

The invention relates to compositions for producing polymethacrylimide foams having reduced pore size. The inventive method allows production of a microporous foam with an especially homogeneous pore size distribution without having to use insoluble nucleation agents.

Thermostable microporous polymethacrylimide foams

A diaphragm for an electroacoustic transducer has a) a core layer containing poly(meth)acrylimide foam and b) at least one cover layer. The diaphragm is produced by laminating the cover layer with the core layer, using a pressure of 0.4 MPa and a temperature of 160&deg; C., whereby at least the side of the core layer which comes into contact with the cover layer is compressed. The resultant composite is subsequently cooled to a temperature below 80&deg; C., before the pressure is reduced to the ambient pressure. The process can be carried out as a single-step process. The diaphragms produced by this process demonstrate an excellent stability, whereby the cover layers in particular are highly resistant to separation.

Process for a diaphragm for electroacoustic transducers

What is disclosed is a method for making a laminate comprising a hard foam layer and a fiber-reinforced synthetic resin layer, which method comprises heating and compressing, in two steps, at least one layer of a high-temperature resistant hard foam and at least one layer of a fiber-containing synthetic resin capable of flowing and of hardening when heated, wherein in a first step, the temperature and pressure employed are sufficient for initiating flow of the synthetic resin and are applied until the synthetic resin has completed flowing, said pressure having a value exceeding the compressive strength of the foam at the temperature employed but not exceeding its compressive strength at room temperature and, wherein in a second step, at a temperature and for a time sufficient to complete hardening of the synthetic resin, pressure is applied which does not exceed the compressive strength of the foam at the temperature used.

Method for making laminates comprising a hard foam layer and a

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Rodgau, Germany

Leonhard Maier