Modified Polyols for Improved PU Adhesives

Title: POLYOL COMPOSITIONS FOR HOT MELT ADHESIVES

 Number/Link:WO2015/127276

Applicant/Assignee: IFS Industries

Publication date: 27-08-2015

Gist”: Polyester diols are partially capped with bulky glycidyl esters

Why it is interesting: According to this invention polyester (or polyether) polyols which are partially capped with a bulky glycidyl ester can be used to improve the adhesive properties of (reactive) polyurethane (hotmelt) adhesives. Specifically the adhesion to materials with low surface energies like ABS or polyolefines is said to improve. In the examples polyester diols prepared from adipic acid and hexanediol with a Mn of about 3000 are partially capped with the glycidyl ester of neodecanoic acid (“Versatic Acid 10”) and used in PU adhesive formulations.

Glycidyl ester of neodecanoic acid

Glycidyl ester of neodecanoic acid

Non-Isocyanate Polyurethane Using Thiol-Ene “Click Chemistry”

Title: POLY(HYDROXYL URETHANE) COMPOSITIONS AND METHODS OF MAKING AND USING THE SAME

 Number/Link: US20140182784

Applicant/Assignee:  Inventors but with US goverment interest

Publication date: 3-07-2014

Gist”: Crosslinked poly(hydroxyurethanes) are prepared by reacting a cyclic carbonate comprising a carbon-carbon double bond, a di-thiol and a polyamine.

Why it is interesting: According to this invention hydroxyurethanes are produced by first reacting a cyclic carbonate which has a double bond (e.g. 4-vinyl-1,3-dioxolan-2-one) with a dithiol (e.g. 1,6-hexanedithiol) using UV radiation and a UV initiator. The resulting di-carbonate is then reacted with a polyamine (e.g. diethylene triamine) resulting in a crosslinked poly(hydroxyurethane). Alternatively the carbonate-amine reaction can happen before the thiol-ene ‘click’ reaction. The materials can be used for binders and adhesives a.o.  The reactions have the advantage of being solvent-, catalyst- and isocyanate-free and having a high yield.

Thiol-ene reaction followed by carbonate-amine reaction

Thiol-ene reaction followed by carbonate-amine reaction

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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