Hybrid Polyisocyanurates for Composites and Coatings

Patent Title: DUAL-CURING ISOCYANURATE POLYMERS

 Number/Link:WO2018/087395 WO2018/087396  WO2018/087399 (German)

Applicant/Assignee:  Covestro

Publication date: 17 May 2018

Gist”:  Di-isocyanate trimer is reacted with hydroxymethacrylates and polyacrylates in the presence of a trimerization catalyst. 

Why it is interesting: According to these inventions a reaction system with two curing modes can be prepared by mixing high functionality oligomeric isocyanate, ethylenically unsaturated compounds, unsaturated compounds containing isocyanate-reactive groups, timerization catalyst and a free-radical initiator at an NCO index of 100 to 200. The system shows a relatively low viscosity and can e.g. be used in fiber-reinforced composites and in coatings. In the examples HDI trimer is reacted with hexanedioldimethacrylate and hydroxypropylmethacrylate in the presence of potassium acetate and a peroxybenzoic acid.

HDI isocyanurate

HDI-trimer


TPU/PU-Acrylate Semi-IPNs

Patent Title: THERMALLY STABLE MICROSTRUCTURED SEMI-IPN LAYER

 Number/Link: WO2016/191118

Applicant/Assignee: 3M

Publication date: 1-dec-2016

Gist”:  TPU and PU-acrylate oligomers are blended and radiation-cured

Why it is interesting: According to this invention semi-interpenetrating polymer networks (IPNs) that are prepared from thermoplastic polyurethane (or urethane/urea) and acrylate-functional polyurethane oligomers are highly heat-stable and abrasion resistant and can be used for the production of microstructured surfaces.  Microstructured (‘riblet’) surfaces with dimples or ridges of a few to a few hundred microns deep are used as drag reducing coatings on planes, ships and in aeronautics. In the examples 90% of a commercial TPU is blended and co-extruded with 10% of a commercial aliphatic urethane acrylate oligomer.  The extruded film was then laminated on on a microreplicated liner, radiation cured and removed from the liner to produce the riblet surface.

Microstructured layer according to the invention

Microstructured layer according to the invention

Dispersions of Comb-Structured Polyurethanes

Patent Title: POLYURETHANE-BASED BINDER DISPERSION

 Number/Link: WO2016122569

Applicant/Assignee: Hewlett-Packard

Publication date: 4-08-2016

Gist”:  Aqueous dispersions of “1,2”-dihydroxypolyacrylate -based polyurethanes

Why it is interesting: According to this invention aqueous dispersions can be made of “comb -structured” polyurethanes which are based on polyols having two hydroxyl groups at one end of the chain.  The “1,2”-diols are made by copolymerizing (e.g.) methylmethacrylate and n-butylmethacrylate together with thioglycerol up to a Mw of about 2000. The polyols can then be reacted with isocyanate and dimethylolpropionic acid for dispersion in water. The dispersions are said to have a small average particle size (10-100 nm) and be especially useful as binders for inkjet-ink.

Thioglycerol

Thioglycerol

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

Hydrazine

 

Urethane-Acrylate Latex

Patent Title: HIGH SOLIDS, LOW VISCOSITY URETHANE-LINKAGE CONTAINING LATEX AND METHOD OF PRODUCTION THEREOF

 Number/Link: WO2015/195466

Applicant/Assignee: Arkema

Publication date: 23-12-2015

Gist”: Simultaneous emulsion polymerization of acrylate, hydroxyacrylate and diisocyanate

Why it is interesting: According to this invention a low viscosity and high solid-content latex, containing urethane bonds, can be produced by emulsion polymerization of a diisocyanate  and a mixture of ethylenically unsaturated monomers some of which are isocyanate-reactive. In an example H12MDI is emulsified in water together with hydroxyethyl acrylate, a mixture of other acrylate monomers and an appropriate surfactant.  The emulsion is then polymerized using a peroxide. The resulting latex had a solid content of 52% at a visosity of 480 cP.  The latex is said to be especially useful for coatings with improved chemical resistance and toughness.

Hydroxyethyl acrylate

Hydroxyethyl acrylate