All posts tagged hybrid

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

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

Self-Crosslinkable Polyurethane

Patent Title: Self-Crosslinkable Polymer and Aqueous Dispersion Comprising Particles of the Same

Number/Link: US2016/0159959

Applicant/Assignee: Valspar Sourcing

Publication date: 9-06-2016

“Gist”: Aqueous dispersion of polyurethane having both azide and carbonyl groups in the backbone

Why it is interesting: Properties of water-based PU coatings can often be improved by incorporating olefinically unsaturated groups in the polymer which can be crosslinked using radiation. According to this invention a self-crosslinking (i.e. without the need for radiation) aqueous PU coating composition can be made by incorporating both azide- and carbonyl groups into the PU backbone. When the water evaporates and the film forms these groups will react forming a hydrazone-type bond. The self-crosslinkabe polymer can be prepared by first making an NCO-ended prepolymer containing a reactive double bond, by (e.g.) reacting some of the NCO groups with hydroxyethylmethacrylate (HEMA). This prepolymer is then dispersed in water together with hydrazine and and acrylate like MMA or BA. The hydrazine will react with the NCO groups, introducing azide groups into the backbone. The acrylate and the prepolymer are then suspension polymerized using an initiator. The PU backbone can (optionally) contain a water dispersible group – e.g. by incorporating dimethylolpropanoic acid. The self-crosslinkable polymer is said to be especially useful for use in wood coating compositions.

Hydrazine

Innovation in Polyurethanes

All posts tagged hybrid

Polyurethane Prepolymer with Very Low Monomeric Isocyanate Content

Hybrid PU-Peptide PUDs

Self-Crosslinkable Polyurethane

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