Dear Dr. Wan Mohamad Ikhmal ,

in my opinion, WB polyurethane coatings fall into the third category (emulsion).

To corroborate my answer, I am attaching the following technical note:

-Classification and characteristics of waterborne coatings - waterborne polyurethane coatings by Sinograce Chemical

Available at: https://www.sinogracechem.com/classification-and-characteristics-of-waterborne-coatings-waterborne-polyurethane-coatings_n184

My best regards. Pierluigi Traverso.

Dear Wan Mohamad Ikhmal, because they show many adventages over other resins such as acrylics. Among the most prominent benifits: organic/toxic solvents are replaced by water, no free residual isocyanates, high performance, economically benificial, less polluants and less harmfull to operators, and others. My Regards

https://doi.org/10.1080/01932691.2017.1327818

https://www.azom.com/amp/article.aspx?ArticleID=8561

Dear Dr. Wan Mohamad Ikhmal ,

as waterborne paints, polyurethane aqueous dispersions are obtained from polyurethanes having ionic groups in their structure. It allows the production of a stable dispersion of polyurethane in water. Polyurethane waterborne paints are used to coat fabrics, leather, paper, and wood flooring. However, their most important applications are coating products for the automotive industry.

In addition to the interesting answer and bibliographic references of Dr. Abdelkader BOUAZIZ , I suggest you to have a look at the following papers/note:

-Waterborne Polyurethanes as a New and Promising Class of Kinetic Inhibitors for Methane Hydrate Formation

Farhadian, A., Kudbanov, A., Varfolomeev, M.A. et al.

Scientific Reports, Vol 9, Article number: 9797 (2019)

Available at: https://www.nature.com/articles/s41598-019-46274-w

or on RG, at: https://www.researchgate.net/publication/334259040_Waterborne_Polyurethanes_as_a_New_and_Promising_Class_of_Kinetic_Inhibitors_for_Methane_Hydrate_Formation

-Structures, properties and applications of the polyurethane ionomers

Król, P., Król, B.

Journal of Materials Science, Vol. 55, pages73–87 (2020)

Available at: https://link.springer.com/article/10.1007/s10853-019-03958-y

-CHAPTER 1:Biobased Hyperbranched Polyurethane , in Biobased Smart Polyurethane Nanocomposites: From Synthesis to Applications, 2017, pp. 1-40 DOI: 10.1039/9781788011891-00001

eISBN: 978-1-78801-189-1

From Book Series: Smart Materials Series

Available at: https://pubs.rsc.org/en/content/chapterhtml/2017/bk9781788011808-00001?isbn=978-1-78801-180-8&sercode=bk

-Synthesis of Cationic Waterborne Polyurethanes from Waste Frying Oil as Antibacterial Film Coatings

Sivaphol Phunphoem, Onusa Saravari, and Pitt Supapho

International Journal of Polymer Science, Vol. 2019 - Article ID 2903158 (2019)

Available at: https://www.hindawi.com/journals/ijps/2019/2903158/

-A Two-Pack Waterborne Polyurethane Topcoat for Military Aircraft

By American Coating Associations

Available at: https://www.paint.org/coatingstech-magazine/articles/two-pack-waterborne-polyurethane-topcoat-military-aircraft/

Good work and my best regards, Pierluigi Traverso.

Because of hit

Can you elaborate your answer Dr. Asmaa S.J.M Al-Ragehey ?

Dear Dr. Pierluigi Traverso ,

I want to ask a simple question in regards to WB polyurethane. To my understanding, waterborne can be classified into 1) water-reducible, 2)water dispersible or colloidal, and 3) emulsion (latex). So which class is the WB polyurethane?

my background education is in physics, and I am really new in this waterborne topic. If you can clarify it, I will be really grateful. Thank you in advance...

Dear Dr. Wan Mohamad Ikhmal ,

in my opinion, WB polyurethane coatings fall into the third category (emulsion).

To corroborate my answer, I am attaching the following technical note:

-Classification and characteristics of waterborne coatings - waterborne polyurethane coatings by Sinograce Chemical

Available at: https://www.sinogracechem.com/classification-and-characteristics-of-waterborne-coatings-waterborne-polyurethane-coatings_n184

My best regards. Pierluigi Traverso.