Fingerprint Resistant Coatings

Patent Title: COATINGS COMBINING OIL-ABSORBING AND OIL-REPELLING COMPONENTS FOR INCREASED SMUDGE RESISTANCE

 Number/Link: WO2018/032356

Applicant/Assignee:  HRL Laboratorories

Publication date: 15 February 2018

Gist”: Phase separated polyurethanes with oleophilic dispersed phase and oleophobic continuous phase (or vice versa) behave as anti-smudge materials.

Why it is interesting: Anti-smudge coatings are of great interest for smartphones and other touch screen devices and are currently made from oleophobic materials, i.e. materials showing a small contact angle vs. oils. According to this invention improved anti-smudge properties can be achieved by using a material having discrete inclusions in a continuous matrix. The matrix material needs to be oleophilic, while the inclusions are oleophobic (or vice versa) and the inclusions need to be smaller than 50nm so not to scatter visible light.  A coating like this can be prepared from a segmented polyurethane comprising (e.g.) a polybutadiene soft phase and a perfluoro/isocyanate/TMP hard phase. It is said that the oleophobic phase will repel the oil while the oelephilic phase will absorb it, leaving a smudge-free surface.
Question remains what happens when the oily phase gets saturated..

smudgecoating

Schematic representation of the invention

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

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

Isocyanate-Free Polyurethanes Using Azide-Alkyne Click Chemistry

Title: SYNTHESIS OF POLYURETHANE POLYMERS VIA COPPER AZIDE-ALKYNE CLICK CHEMISTRY FOR COATINGS, ADHESIVES, SEALANTS AND ELASTOMER APPLICATIONS

 Number/Link: WO2014/122153

Applicant/Assignee: Sika

Publication date: 14-08-2014

Gist”: Polyurethane prepolymers capped with azides and alkynes are reacted using copper catalysis.

Why it is interesting: Because of safety, health and envriromental issues, isocyanate-free systems have clearly been gaining in importance the last few years.  Especially for coatings, adhesives and OCF applications, alternative curings systems are being developed. In the current invention an isocyanate-free system is based on the reaction between a prepolymer having at least two azide groups and a prepolymer having at least two alkyne groups. The reaction is copper catalyzed such that it can be performed at ambient temperature. The first prepolymer is (pref.)  prepared by reacting an isocyanate ended prepolymer with glycidol (2,3-epoxy-1-propanol) and subsequently with sodium azide. The second prepolymer is similarly prepared by reacting an isocyanate ended prepolymer with propargyl alcohol (2-propyn-1-ol).  The systems are said to be especially useful for roof coatings.

Example of an azide-alkyne reaction resulting in 1,4-disubstituded triazoles.

Example of an azide-alkyne reaction resulting in 1,4-disubstituded triazoles.

 

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.