Polythiourethanes for 3D Printing

Patent Title:  THIOURETHANE POLYMERS, METHOD OF SYNTHESIS THEREOF AND USE IN ADDITIVE MANUFACTURING TECHNOLOGIES

 Number/Link: WO2017/0267804

Applicant/Assignee:  Univ. Texas

Publication date: 21-September-2017

Gist”: Photolatent bases are used to catalyse the polythiol-polyisocyanate reaction

Why it is interesting: According to this invention reactive systems useful for additive manufacturing processes can be prepared from polythiols, diisocyanates and a photolatent base.  When irradiated the photolatent base will split off a non-nucleophilic base which will catalyse the thiol-isocyanate reaction. The systems can be prepared such that the resulting materials show improved mechanical properties over current 3D printed materials.  In an example 2,2′-(ethylenedioxy)diethanethiol and pentaerithritol tetrakis(3-mercaptopropionate) are reacted with HDI using 1,1-dimethyl-1-(2-hydroxypropyl)amine-p-nitrobenzimide (DANBA) as a photolatent base.

Example of pholatent base (DANBA)

Soft Ionomeric TPU

Patent Title: SOFTENING THERMOPLASTIC POLYURETHANES USING IONOMER TECHNOLOGY

 Number/Link: US20160347900

Applicant/Assignee: Univ. Akron; Covestro

Publication date: 1-Dec-2016

Gist”: TPU is prepared with ionomeric groups having bulky counter-ions

Why it is interesting: According to this invention a novel type of plasticized thermoplastic polyurethane can be made  by incorporating as chain extender a diol containing an ionic group with a bulky counter ion. It is said that the steric hindrance of the bulky counter ions creates additional free volume that softens the polymer and lowers the melt viscosity. In the examples N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (BES) is used together with bulky alkylammonium cations. The softest TPU shown has a 37 Shore A hardness at 25% hardblock content and 7.6 mole% BES-tetrakis(decyl)ammonium. This accounts for a 35 point hardness decrease compared to an ionomer-free control sample.

N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid

N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid

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