All posts in category Adhesives-Coatings

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/

More Non-Isocyanate Polyurethanes

Title:  METHOD FOR PREPARING POLY(CARBONATE-URETHANE) OR POLY(ESTER-URETHANE)

 Number/Link: US20130144027

Applicant/Assignee: CENTRE NAT RECH SCIENT; TOTAL RES & TECHNOLOGY

Publication date: 6-06-2013 (priority PCT/EP)

“Gist”: Non-isocyanate polycarbonate- or polyester- polyurethane with very high softblock molecular weight produced by “immortal” ring opening polymerization.

Why it is interesting: Non-isocyanate PU systems appear to become a growing trend – at least in scientific and patent literature. In addition to not using phosgene or isocyanates, advantages quoted are improved biodegradability and recyclability.  The current invention teaches the use of “immortal” ringopening polymerization to polymerize 5,6 or 7 membered cyclic carbonates or cyclic esters. This type of ROP is highly efficient and is described in e.g. US2011092664.  The resulting polymer is subsequently modified with anhydrides to a polymer with carboxylic end-groups, which are then reacted with cyclic carbonates bearing hydroxyl groups.  The resulting polymer has a MW of (preferably) 50,000 to 100,000 and can be reacted with polyamines to produce the polyurethanes. See the reaction scheme below.

Reaction sequence according to the invention

Reaction sequence according to the invention

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by Gerhard Bleys on June 11, 2013  •  Permalink
Posted in Adhesives-Coatings, Polyols
Tagged , , , , , ,

Posted by Gerhard Bleys on June 11, 2013

https://purpatents.com/2013/06/11/more-isocyanate-free-polyurethanes-2/

Polyurethane OCF Systems with Low Monomeric Isocyanate Content

Title: IMPROVED POLYURETHANE FOAM COMPOSITION

 Number/Link: WO2013/072380

Applicant/Assignee: SOUDAL

Publication date: 23-05-2013

“Gist”: Use of mono-alcohols to reduce monomeric isocyanate content in OCF systems.

Why it is interesting: OCF , or one component foam (or froth) systems are isocyanate ended prepolymers, mixed with organic blowing agents and other additives like catalysts. They are often prepared directly into pressure cans and are mostly used in construction as adhesives and sealants.  Curing happens by reaction with ambient moisture. Recent changes in legislation has forced OCF producers to drop the amount of free monomeric isocyanate in their systems.  In this invention OCF systems with less than 1% free monomeric MDI are produced by reacting a conventional diol, a polymeric/monomeric MDI mixture and a relatively low MW monol (2-ethyl-hexanol in the examples).  The monol allows to produce prepolymers with low NCO content and low free MDI by preventing chain extension and therefore avoiding extreme viscosity build-up.

OCF system in pressure can.

OCF system in pressure can.

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by Gerhard Bleys on May 28, 2013  •  Permalink
Posted in Adhesives-Coatings, Rigid Foams
Tagged , ,

Posted by Gerhard Bleys on May 28, 2013

https://purpatents.com/2013/05/28/polyurethane-ocf-systems-with-low-monomeric-isocyanate-content/

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