PU-FPOSS Coating Compositions

Title: ICE ADHESION REDUCING PREPOLYMERS AND POLYMERS

Number/Link: US20170204291

Applicant/Assignee: Boeing

Publication Date: 20 July 2017  (published as PCT)

“Gist”: Ice repellent polyurethane coatings are prepared by incorporating F-POSS prepolymers

Why it is interesting: The invention is about coated surfaces that show reduced ice formation and/or adhesion. This is accomplished by incorporating fluorinated polyhedral oligomeric silsesquioxanes (F-POSS) into the composition. OH-functional F-POSS is prepared as per the scheme below, which is then reacted with polyisocyanates to prepare an NCO-functional F-POSS prepolymer.  The prepolymer can then be used in PU coating compositions, or reacted with amino-functional PDMS compounds and used as an additive in coating compositions.
It is believed that the F-POSS particles interfere with H-bond formation of ice to the coated surface.  Ice repellent surfaces are particularly useful for aircraft, wind turbines, cooling equipment an the like.

Synthesis of OH-functional trifluoropropyl POSS

PU-Acrylate/Epoxy IPN for 3D Printing

Patent Title: PHOTOCURABLE COMPOSITIONS FOR THREE-DIMENSIONAL PRINTING

 Number/Link:  WO 2016/153711

Applicant/Assignee: Dow

Publication date: 29-09-2016

Gist”: Acrylate-capped PU prepolymer is copolymerized with epoxides using UV radiation

Why it is interesting: This case is about UV-curable compositions to make flexible materials using additive manufacturing, especially stereolithography.  A prepolymer of an isocyanate and a ‘flexible’ polyol is capped with a hydroxy-functional acrylate, then mixed with a multifunctional epoxy, a multifunctional acrylate ‘monomer’ (a crosslinker also acting as reactive diluent) and two photoinitiators:  one radical and one cationic.  In the example a 6 to 8000 Mole weight diol is capped with TDI and then with hydroxyethyl acrylate.  The prepolymer is then mixed with 3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, 1,6-hexanedioldiacrylate and two photoinitiators.  After UV curing the materials had a shore A hardness between about 60 and 80 and an elongation at break between about 70 and 200.

3,4-Epoxycyclohexylmethyl-3,4- epoxycyclohexane carboxylate

3,4-Epoxycyclohexylmethyl-3,4-
epoxycyclohexane carboxylate

Polyurethane Prepolymer with Very Low Monomeric Isocyanate Content

Patent Title: ULTRALOW MONOMER POLYURETHANES

 Number/Link: WO 2016/142513

Applicant/Assignee: Henkel

Publication date: 15-09-2016

Gist”: An NCO-ended prepolymer is reacted with a bis(alkoxysilylalkyl)amine

Why it is interesting: This invention is about laminating adhesives with a ‘primary aromatic amine migration limit’ of less than 10ppb, in accordance with the EU regulation for food packaging laminates. The low monomeric content is achieved by first making a NCO-ended prepolymer, which is then reacted with an monofunctional ‘H-acidic’ compound, preferably a bis(alkoxysilylalkyl)amine.  In an example a mixture of diols (OHv 108 to 236) was  reacted with 2.4-TDI down to an NCO value of 3.85%. Then 4,4′ MDI, trimethylolpropane and a triiso based on TDI were added to an NCO value of 2.2%.  Finally the prepolymer was reacted with bis(3-(triethoxysilyl)proplyl)amine at an NCO/NH ratio of 7:1.  Final NCO value was 2% with 0.05% (w/w) free 2,4-TDI and less than 0.01% free 4,4′-MDI. The prepolymer is said to be useful in 1K and 2K adhesive compositions and is said to have better adhesion properties and reactivity compared to NCO-free adhesives like sile silane-terminated PU adhesives.

Bis(3-(triethoxysilyl)propyl)amine

Bis(3-(triethoxysilyl)propyl)amine

Hybrid PU-Peptide PUDs

Patent Title: AQUEOUS PEPTIDE-FUNCTIONALIZED POLYURETHANE DISPERSIONS

 Number/Link: WO2016/135162

Applicant/Assignee: Henkel; Max-Panck Ges.

Publication date: 1-09-2016

Gist”: A maleimide-capped prepolymer is reacted with the -SH groups in a peptide

Why it is interesting: Polyurethane-protein hybrids are interesting novel materials which potentially have a number of unique properties unattainable with conventional synthetic polymers. In a previous case discussed in this blog an NCO-ended polyurethane prepolymer was reacted with a peptide in water to make a PU-peptide dispersion.  This type of grafting, however, is not very specific because the isocyanate will react mostly with the free amino groups of lysine, which is usually  ‘abundant’ in a typical peptide. According to this invention the grafting can be made very specific by first end-capping the NCO prepolymer with maleimide groups and dispersing in water. The dispersion is then reacted with a peptide solution at pH7. In these circumstances the maleimide will react selectively with the free thiol group of cysteine, of which usually very few are present in a typical peptide because most thiol groups are engaged in S-S disulfide bridges.  Preferably a peptide consisting of 10-200 amino acids is used, with preferably only one free thiol group. By selective grafting the properties of the peptide can be conserved.  The PU-peptide dispersions are claimed to be especially useful for metal adhesives.

L-cysteine

L-cysteine

 

 

Polyurethane Elastomer with High Dielectric Constant

Patent Title: DIPOLE-MODIFIED POLYURETHANE, METHOD FOR PRODUCING SAME, AND USE THEREOF IN THE PRODUCTION OF CAST ELECTROACTIVE POLYURETHANE-BASED ELASTOMER FILMS

 Number/Link: WO2016102320  (German)

Applicant/Assignee: Covestro

Publication date: 30-06-2016

Gist”: A molecule with high dipole moment is incorparted in the PU backbone

Why it is interesting: According to this invention a polyurethane with an increased dielectric constant can be prepared by first reacting an isocyanate (f>2)with a hydroxyl-functional dipole.  This ‘dipole-modified’ isocyanate is then used in a (preferred) amount of 5-10% on the rest of the isocyanate of an elastomer formulation.  The dipole is of the form HO-R-D-X-A, where  D is an electron donor, A is an electron acceptor and X is a residue with a delocalized electron system.  In an example N-2-hydroxyethyl-N-methyl-4-nitroanilin is reacted with a biuret based on HDI to make the ‘dipole-modified’ isocyanate. Polyurethane elastomer films with high dielectric constant can be used as electromechanical transducers in sensors, actuators, artifical muscle etc..

N-2-Hydroxyethyl-N-Methyl-4-Nitroanilin

N-2-Hydroxyethyl-N-Methyl-4-Nitroanilin

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