Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Quarzwerke Gmbh

Olaf Mühling

Ralf Ruhmann

Arno Seeboth

Jörg Ulrich Zilles

Dirk Kruber

Renate Vetter

Polymer particles having a mean primary particle diameter d50 between 50 nm and 10 pm based on the total weight, containing: A. 10 to 100% by weight of a polymer phase A, obtainable by free-radical copolymerization of an oil-in-water miniemulsion having a monomer mixture as oil phase, containing i) 30 to 99.9% by weight of one or more mono-ethylenically unsaturated monomers II having at least one C-C-n-alkyl side chain, ii) 0 to 60% by weight of one or more mono-ethylenically unsaturated monomers II having at least one C-C-n-alkyl and/or one C-C-i-alkyl side chain, iii) 0.1 to 20% by weight of one or more monomers III having at least two non-conjugated ethylenic double bonds, iv) 0 to 69.9% by weight of one or more (hetero)aromatic, mono-ethylenically unsaturated monomers IV, v) 0 to 40% by weight of one or more other mono-ethylenically unsaturated monomers V; and B. 0 to 90% by weight of a polymer phase B, obtainable by subsequent free-radical graft copolymerization, in the presence of the polymer phase A obtained after stage A), of a monomer mixture containing i) 0 to 100% by weight of one or more monomers VI from the group of C-C-alkyl(meth)acrylates, ii) 0 to 100% by weight of one or more (hetero)aromatic, mono-ethylenically unsaturated monomers VII, iii) 0 to 50% by weight of one or more other mono-ethylenically unsaturated monomers VIII, where the percentages by weight of the monomer mixtures used in the respective stages add up to 100% by weight.

Thermotropic polymers

The invention relates to doping capsules which have a substance which displays a decreasing transparency with increasing temperature within a defined temperature range due to physicochemical interactions with the polymer matrix to be doped. Likewise, the invention relates to composite systems which have a polymer matrix doped with the doping capsules. The capsules according to the invention are used for sun protection or heat reflection.

Doping capsules, composite systems comprising these and also use thereof

The invention relates to a composite with inverse thermochromic properties, the composite changing from a colorless into a colored state with increasing temperature. The composite thereby contains a colorant, a developer and a fluxing agent and also an inorganic filler. The invention likewise relates to a composite material which contains a polymer-based matrix into which at least one composite with inverse thermochromic properties is doped. These composite materials are used in the field of sensor technology, solar technology, transport and communications technology and medical technology.

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Berlin, Germany

Olaf Mühling