PUDs for Superhydrophobic Coatings

Patent Title: Vegetable Oil-Modified, Hydrophobic Polyurethane Dispersions

Number/Link: US20160009852

Applicant/Assignee: Rust-Oleum

Publication date: 14-01-2016

“Gist”: PUDs containing saturated monoglycerids

Why it is interesting: Aqueous polyurethane dispersions are popular for use in environmentally friendly coating compositions. Because of the inherent presence of hydrophilic (often acid-) groups to stabilise these dispersions, the resulting coatings often lack hydrolytic stability. According to this invention, this can be improved by incorporating monoglycerids, prepared by reacting vegetable oils with glycerol followed by distillation, into the PU backbone. A prepolymer is prepared by reacting the monoglicerids, together with a non-isocyanate urethane polyol (prepared from polyamines and monocyclic carbonates), a conventional long-chain polyol and dimethylolpropionic acid, with an excess of isocyanate. The prepolymer is then neutralized with an amine and subsequently reacted with a chain extender in water to make the PUD. Coatings made with these dispersions are said to be superhydrophobic and have a low friction coeficient.

Dimethylolpropionic acid

TPU Powder for SLS

Patent Title: USE OF THERMOPLASTIC POLYURETHANE POWDERS

Number/Link: WO2015/197515 (German)

Applicant/Assignee: Covestro

Publication date: 30-12-2015

“Gist”: TPU with very specific melt properties can be used for selective laser sintering

Why it is interesting: Additive manufacturing and “3D printing” using TPU is not new and has been mentioned before in this blog, e.g. the use of TPU in for fused deposition modelling. Fused deposition modelling is a technique where molten thermoplastics are extruded. In powder-based techniques on the other hand, thin layers of thermoplastic powder are selectively ‘sintered’ together using lasers or IR beams. Powder techniques like laser sintering are said to have economic advantages and allow for the production more complex shapes, but suffer from low mechanical properties and brittleness. According to this application, TPU powders with specific hardness and melt characteristics (as outlined in claim 1) allow for laser-sintered objects with improved mechanical properties. In the examples a TPU is prepared from a butanediol-adipic acid polyester diol, butanediol chain extender and 4,4’MDI. The TPU, together with some ‘fumed’ silica flow-improvement additive, is then cryogenically grinded to an average particle size of less than 150 micron and subsequently used for laser sintering.

Tetrahedron made by SLS (© Wikimedia)

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

Innovation in Polyurethanes

PUDs for Superhydrophobic Coatings

TPU Powder for SLS

Urethane-Acrylate Latex

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