All posts tagged nano

A New Way to Remove Monomeric Isocyanate from Prepolymers

Title: REDUCTION OF THE FRACTION OF MONOMERS COMPRISING ISOCYANATE GROUPS IN MOISTURE-CURING POLYURETHANE COMPOSITIONS

 Number/Link: US2013/0158210

Applicant/Assignee: Sika

Publication date: 20-06-2013 (priority PCT/EP)

“Gist”: Reduction of monomeric MDI in moisture curable prepolymers by addition of amino functional silica particles.

Why it is interesting: As noted in some previous posts in this blog (*) reduction of monomeric isocyanate from moisture curable systems is an important trend in PU systems development. The current invention solves this problem by adding isocyanate-reactive SiO2 particles to the prepolymer composition.  The particles have a preferred average size of 50-60μm, are (nano-)porous with a large specific surface area and have been chemically modified with (preferably) aminosilanes to make them amino-functional. Particles of this type with different functional groups are commercially available under the QUADRASIL tradename.
(*) Note that you can use the ‘search’ or ‘category’ boxes on the right (or in case of a mobile device on the bottom) of this page to help you navigate the site.

Porous Silica Particles

Porous Silica Particles

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by Gerhard Bleys on June 27, 2013  •  Permalink
Posted in Adhesives-Coatings, Isocyanates and Prepolymers
Tagged , , , ,

Posted by Gerhard Bleys on June 27, 2013

https://purpatents.com/2013/06/27/a-new-way-to-remove-monomeric-isocyanate-from-prepolymers/

Aqueous Polyurethane Dispersion with Integrated Nanoparticles

Title: AQUEOUS DISPERSIONS OF POLYURETHANE AND NANOPARTICLES

 Number/Link: WO2013/059106

Applicant/Assignee: Bayer

Publication date: 25-04-2013

“Gist”: Amino-functional inorganic nanoparticles are reacted with residual isocyanate groups of a PUD-forming polyurethane prepolymer and subsequently dispersed in water.

Why it is interesting: A water-dispersible polyurethane prepolymer is made from isocyanate, polyol and chain extender in which polyol and/or chain extender comprise ionic or potentially ionic groups.  The prepolymer is produced with a surplus of isocyanate which is subsequently reacted with amino-functional inorganic nanoparticles.  The nanoparticles consist of e.g. metal oxides which were reacted with a “bridging compound” comprising an isocyanate-reactive group (NH2 or OH) and a particle-reactive group e.g. a halogen or silane group. The polyurethane with covalently integrated nanoparticles can then be dispersed in water using a known process.  The resulting PUD has a high shelf-life and can be used in coatings, adhesives, films etc. with improved properties.

Polyurethane dispersion and film made from it. (Wikimedia)

Polyurethane dispersion and film made from it. (Wikimedia)

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by Gerhard Bleys on April 30, 2013  •  Permalink
Posted in Adhesives-Coatings, composites, dispersions, Elastomers
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Posted by Gerhard Bleys on April 30, 2013

https://purpatents.com/2013/04/30/aqueous-polyurethane-dispersion-with-integrated-nanoparticles/

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