With people's emphasis on health and increasingly stringent environmental regulations, water-dispersible polyisocyanates have shown importance in various application fields in recent years. At present, water-dispersed polyisocyanates are mainly used as crosslinking components to prepare water-dilutable two-component polyurethane coatings (2K-PUR coatings), or as additives for water dispersion adhesives, in textile finishing or formaldehyde-free Used in textile printing inks to crosslink water dispersions.
At present, water-dispersible polyisocyanates in most application fields are non-ionic hydrophilic modification through polyethers. Although this type of hydrophilic modified polyisocyanate has been widely recognized in the market in most applications, it also has certain drawbacks, such as its high viscosity, which requires considerable shear force to be uniformly distributed during the construction process. Introduced into the aqueous medium. In order to avoid the above shortcomings, researchers have tried to prepare water-dispersible polyisocyanates by adding ionic groups for hydrophilic modification.
In the reported literature or patents, ion-modified groups include carboxyl, sulfuric acid, hydroxyl, hydroxysulfonic acid, etc., but there are still certain defects, such as carboxyl-modified polymers are prone to gelation and hydroxyl The color of sulfonic acid modified products is obviously yellow. Later, Bayer reported in its patents 3-(cyclohexylamino)-propanesulfonic acid (CAPS) modified polyisocyanates. Research has found that CAPS-modified polyisocyanates can be finely dispersed in water and the product is stable in storage.
Below, the editor of Desheng briefly introduces the preparation method of this type of polyisocyanate. 950 g of polyisocyanate, 50 g of CAPS, 29 g of dimethylcyclohexylamine and 257 g of 1-methoxyprop-2-yl acetate were stirred for 5 hours at 80 degrees Celsius under dry nitrogen, wherein the polyisocyanate was based on hexamethylene Diisocyanate (HDI) and contains isocyanurate groups, NCO content is 21.7%, average NCO functionality is 3.5, monomer HDI content is 0.1% and viscosity is 3000 mPas. After cooling to room temperature, a colorless and transparent polyisocyanate solution can be obtained.
Believe that you will see here that you will conclude that CAPS-based modified polyisocyanates show certain advantages over other ionic or non-ionic modified products. In addition, as environmental protection requirements become more stringent and people’s awareness of environmental protection increases, the market acceptance of water-based coatings will gradually surpass that of solvent-based coatings as people implement a healthy and environmentally friendly life.
The CAPS produced by Desheng Company has not only been widely used in the new coating market, it is also popular in the biochemical field, because it is also a biological buffer, which is very widely used in biochemical diagnostic kits, DNA/RNA In the extraction kit and PCR diagnostic kit, if you have any questions or needs, please go to the official website to consult customer service staff.
