CAPS buffer helps improve the performance of water-based coatings

With increasingly strict environmental regulations, the coating industry is transitioning from solvent based products to water-based systems. However, water-based two-component polyurethane coatings face a technical challenge in the development process: how to ensure stable mixing and long-term coexistence of hydrophilic resins and hydrophobic polyisocyanate curing agents. CAPS buffer (3-cyclohexylaminepropanesulfonic acid) is the key additive to solve this problem.

Compatibility with active group resins

CAPS can be used in various environmentally friendly high-quality water-based two-component polyurethane coatings. At room temperature, CAPS can coexist stably with resins containing active groups such as hydroxyl, carboxyl, amino, epoxy, etc. for a long time. This characteristic means that CAPS will not react prematurely with the main resin, nor will it catalyze the side reaction to cause the system viscosity to rise or gel after being added to the formula. It can be added in the early stages of coating preparation, accompanying the entire production, storage, and use process without causing performance degradation.

Modification reaction of isocyanates

CAPS can react with aliphatic polyisocyanates under mild conditions, and the reaction process requires the presence of a tertiary amine neutralizing agent. The sulfonic acid ester derivatives generated by this reaction are excellent emulsifiers. The polyisocyanate modified by CAPS introduces hydrophilic sulfonic acid groups into its molecular structure, enabling the originally hydrophobic curing agent to acquire self emulsifying ability. When the modified curing agent is added into water, it can automatically disperse into small lotion particles without external force or additional emulsifier.

Storage stability and lotion quality

The polyisocyanates modified by CAPS exhibit good storage stability. Even if it contains less sulfonate groups, it can also obtain a well dispersed lotion in water, and the lotion is not muddy in appearance. This is very important for the production and use of coatings - good storage stability means that coatings can be stored in warehouses for months without delamination, precipitation, or abnormal viscosity changes; Good lotion quality is directly related to the final appearance and performance of the coating film, to avoid surface defects such as shrinkage cavity and orange peel caused by uneven dispersion.

Comprehensive benchmarking of coating performance

The water-based two-component polyurethane coating prepared using CAPS modified polyisocyanates can fully compare with general solvent based coatings in three key indicators: dryness, curing, and chemical resistance. Drying determines how long after construction can the next process be carried out or put into use; The degree of curing affects the final hardness and mechanical properties of the coating film; Chemical resistance is related to the coating's ability to resist corrosion from water, oil, acid, and alkali during use. The performance of these three aspects has reached the level of solvent based coatings, which means that water-based coatings are no longer a compromise alternative, but a truly environmentally friendly choice with equal protection capabilities.

Formaldehyde removal additional function

It is worth noting that CAPS also has the function of removing formaldehyde in water-based coatings. This additional feature further enhances the value of CAPS in coating formulations, especially in indoor decorative coatings, where formaldehyde removal ability is a selling point that attracts consumer attention.

Hubei Xindesheng Material Technology Co., Ltd. focuses on the research and production of high-end buffering agents. The CAPS products produced by the company adopt advanced synthesis technology, with high purity, low impurities, and excellent batch stability. The product has been widely used in various fields such as water-based coatings, biopharmaceuticals, electrophoresis buffers, etc., and has been widely recognized by customers. If you have any related procurement needs in the near future, please feel free to contact me at any time!