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)

Moisture Scavenger for Polyurethane Coatings

Title: PROCESSES FOR MOISTURE SCAVENGING IN PREPARING POLYURETHANE COATINGS AND COMPOSITIONS THEREFOR

Number/Link: US2017/0114247

Applicant/Assignee: Achiewell

Publication Date: 27-april-2017

“Gist”: Methoxysilicon compound with e-withdrawing group together with hydrophobic t-amine catalyst acts as moisture scavenger

Why it is interesting:  Moisture in PU coating compositions can be a problem because it negatively affects both the properties of the composition (pot life and viscosity..) and of the final coating. Moisture scavengers like molecular sieves are well known but often have a negative impact as well. According to this invention, methoxyorganosilicon compounds with at least one electron withdrawing group attached to the silicon atom act as efficient moisture scavengers when used in combination with a hydrophobic tert-methylamine catalyst. Preferred organosilicon compounds have 3 methoxy substituents and one hydrocarbon-based e-withdrawing group, like e.g. fluoroethyltrimethoxysilane. A preferred catalyst is 1,3-bis[3-dimethylaminopropyl]urea (claimed).  No examples are given.

1,3-bis[3-dimethylaminopropyl]urea

Infrared Curable 2K PU Adhesives

Patent Title: LATENT TWO-PART POLYURETHANE ADHESIVES CURABLE WITH INFRARED RADIATION

 Number/Link: WO2016/205251 and related cases: WO..5252, WO…5254 and WO..5255

Applicant/Assignee: Dow

Publication date: all published on 22 dec 2016

Gist”: Two-component PU adhesive using 3 different delayed-action catalysts

Why it is interesting: Two component adhesive systems need a sufficiently long ‘open time’ preferably combined with a fast cure once activated, e.g. by heat. Heat curing using infrared radiation allows for ‘spot curing’ , i.e. curing only predetermined parts of the adhesive such that the assembly can be handled and can be cured completely in a subsequent step.  This process is fast and saves energy.  The current invention is about IR curable adhesives containing 3 different types of latent catalysts: a latent room temperature organometallic catalyst based on Sn, Zn or Bi added to the polyol component, a phenol-blocked cyclic amidine and a carboxylic acid blocked cyclic amidine.  The two latter catalysts can either be included in the polyol or in the isocyanate component. The catalysts used in the examples are dioctyltinthioglycolate, phenol blocked 1,8-diazabicycloundec-7-ene and a carboxilic acid blocked 1,8-diazabicycloundec-7-ene.

1,8-diazabicycloundec-7-ene

1,8-diazabicycloundec-7-ene

Spray Foam with Increased Reactivity

Patent Title: POLYOL PREMIX COMPOSITION FOR RIGID POLYURETHANE FOAMS

 Number/Link: WO2016/162362

Applicant/Assignee: Covestro

Publication date: 13-10-2016

Gist”: Addition of dicarboxilic acid reduces cream time in amine catalyzed foams

Why it is interesting: A short cream time has advantages for rigid PU spray foam because it can reduce dripping of the material after application.  According to this invention the cream time of an amine-catalyzed, HFC-blown spray foam composition can -surprisingly-be reduced by addition of a dicarboxilic acid, preferably succinic or glutaric acid. The diacids are used in a ratio of about 2 equivalents acid to 1 equivalent of (free) amine. In the examples a clear reduction of cream time is shown compared to compositions with no diacid, a mono-acid or less than the required amount of diacid. However, all examples also contain some trimerization catalyst (2-hydroxypropyl trimethylammonium formate) next to the tert-amine catalyst (N,N-dimethylcyclohexylamine). It would be interesting to see an example without the trimerization catalyst i.m.o.

Succinic acid.

Succinic acid

 

Formic Acid Blown EPIC Foams

Patent Title: ISOCYANATE-BASED TEMPERATURE-RESISTANT FOAMS WITH HIGH FLAME RESISTANCE

 Number/Link: WO2016/131874

Applicant/Assignee: BASF, Covestro

Publication date: 25-08-2016

Gist”:  One shot rigid isocyanate-epoxy foams blown with formic acid

Why it is interesting: This is the first in a series of (at least) 3 patent applications apparently resulting from a cooperation between BASF and Covestro on epoxy-isocyanate (“EPIC”) foams.  The other applications are WO2016/131878 and WO2016/131880 published on the same date. More publications may follow.
The current invention is about temperature-resistant foams with reportedly very high mechanical properties prepared form a one-shot system comprising a (pref.) high functional MDI, a (pref.) bisphenol-A or bisphenol-F polyglycidylether, at least one reactive amine catalyst and a blowing agent comprising formic acid. The ratio of iso to epoxy groups is (pref.) 3:1 to 15:1. The resulting materials are post-cured at 200°C. The foams contain no, or very little, urethane or urea groups and are said to be especially useful in laminates a.o.  In the examples foams with densities of 25-35 kg/m³ with a thermal conductivity as low as 20 mW/mK are shown.

Bisphenol-F diglycidylether

Bisphenol-F diglycidylether