Evonik Roehm Gmbh

Evonik Degussa Gmbh

Kim Klaus Oehlenschlaeger

Friedrich Georg Schmidt

Stefan Hilf

Christopher Barner-Kowollik

Nathalie Guimard

Jiawen Zhou

Emmanouil Spyrou

Andre Hennig

Jan Mueller

The invention relates to low molecular mass products and to the use thereof as reversible or permanent low-temperature crosslinkers in Diels-Alder reactions.

Low molecular weight products and use thereof as reversible or permanent low-temperature crosslinking agent in Diels-Alder reactions

A method for the reversible crosslinking of, for example, adhesives or coating materials, and a composition stable on storage at room temperature for implementing the crosslinking reaction. The reversible crosslinking method allows very rapid crosslinking even at a low first temperature, and undoing of the crosslinks at higher temperatures, thereby recovering thermoplastic processability and, for example, allowing the originally bonded substrates to be parted from one another again easily. A particular aspect is that a plurality of cycles of crosslinking and undoing of the crosslinks are possible with the present system. A feature of the system used for the reversible crosslinking is that it contains two components, A and B, where component A is a compound having at least two protected dithioester functionalities, preferably cyanodithioester functionalities, and component B is a compound having at least two diene functionalities.

Functional materials with reversible crosslinking

The invention relates to the use of a powder made of a polymer, which of two or more components with functionalities suitable for Diels-Alder reactions, or of a powder mixture (dry blend) made of powders respectively of at least one of the reactive components, where these together enter into the Diels-Alder reaction with one another and are capable of a retro-Diels-Alder reaction, in a rapid-prototyping process. The invention further relates to moldings produced with use of said polymer powder through a layer-by-layer shaping process in which regions of a powder layer are melted selectively. The molding here can be removed from the powder bed after cooling and hardening of the regions previously melted layer-by-layer.

Polymer powder for producing three-dimensional objects

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Hockenheim, Germany

Kim Klaus Oehlenschlaeger