Hydrophobic Coatings from BO Polyols

Title: POLYURETHANE ENCAPSULATE

 Number/Link: WO2014/176390

Applicant/Assignee: Dow

Publication date: 30-10-2014

Gist”: Use of polybutyleneoxide polyols for hydrophobic encapsulants.

Why it is interesting: The encapsulation of water soluble compounds for controlled release, like e.g. plant nutrients and fertilizers, requires a relatively hydrophobic coating.  Often this is accomplished with polyurethane coatings to which hydrophic compounds are added such as castor oil derivatives. These additives can however have a deleterious effect on other coating properties.  According to this invention encapsulation coatings with good mechanical properties and improved water absorption and water vapour transmission properties can be prepared from polybutyleneoxide triols and polymeric MDI without the need for other additives.

Butylene oxide

Butylene oxide

Highly Stable Isocyanate Dispersions

Title: STORAGE-STABLE HYDROPHILIC POLYISOCYANATES

 Number/Link: WO2014/053269   (German)

Applicant/Assignee: Evonik

Publication date: 10-04-2014

Gist”: A uretdion-containing isocyanate prepolymer is reacted with a neutralized aminealkylsulfonic acid to produce a novel hydrophilic (latent) isocyanate which can be used in stable aqueous dispersions.

Why it is interesting: Aqueous dispersions of isocyanates are useful in many applications as adhesives, binders, crosslinkers etc, but usually suffer from a relatively short shelf life.  Dispersions prepared according to the current invention supposedly lose less than 30% of their initial NCO value after 12 weeks storage at 50°C. In an example an aceton-solution of  an IPDI-uretdion prepolymer with an isocyanate content of 1.5% is reacted with the sodium salt of an aminealkylsulfonate in water to an NCO value of 0.1%. After removal of the aceton the resulting dispersion had a latent isocyanate content of 4.5%

Dimerization of isocyanate to uretdion.

Reversible dimerization of isocyanate to uretdion.

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