Say Goodbye to Moisture, The Secret to "Dry" Polyurethane Products, Starting with Choosing A Professional Dehydrating Agent

Polyurethane dehydration

In today's rapidly advancing technology, every corner of life is filled with traces of technology; In the coatings industry, polyurethane produced by the reaction of isocyanates and polyols has been widely used in fields such as construction, automotive, medical, and electronics.

However, polyurethane products are very prone to react with water in humid environments with high humidity, causing performance defects in the products. Due to the similar reactivity of isocyanates with water and polyols, it can lead to shortened storage life of single component coatings and adhesives; The use time of two-component coatings may decrease.

Figure 1 Reaction equation of isocyanate and water

Milliken paint additive Borchers ® Efficient and fast dehydrating agents - Additive TI and Additive OF - can be specifically designed for polyurethane systems. Through different reaction mechanisms, they react quickly with the water in the system to remove it, achieving high stability of the product.

Dehydration technology

The moisture in polyurethane systems also comes from various sources, such as solvents, pigments and fillers, as well as moisture in the air. In traditional dehydration methods, we commonly use two methods: vacuuming to remove water and adding molecular sieves to adsorb water.

However, both methods have certain limitations. Although vacuum drying can remove moisture, it has high energy consumption, high cost, and may have a certain impact on the performance of the coating; Although molecular sieves can effectively adsorb water, their adsorption capacity is limited and they need to be replaced regularly, making the operation cumbersome.

In contrast, Additive TI and Additive OF adopt more advanced dehydration technology, which chemically reacts with the moisture in the coating to convert it into harmless substances, thereby eliminating the impact of moisture on the performance of the coating.

Product recommendation

Additive TI/OF is a low viscosity, high transparency, high reactivity, and 100% active chemical product specifically designed for polyurethane systems to chemically eliminate moisture in solvent based systems through different reaction mechanisms, preventing issues such as low glossiness, haze, and foaming caused by moisture in coatings.

Additive TI

Additive TI is a low viscosity isocyanate with a single functional group and high reactivity. It reacts very quickly with water and can complete dehydration reaction in a short time, effectively improving production efficiency.

Figure 2 Physical properties of Additive TI

#Additive TI Dehydration Rate Test

Figure 3 Additive TI Dehydration Rate Test

As the reaction time increases, the intensity of the infrared absorption peak gradually decreases, indicating that the reaction between Additive Tl and water is very rapid and almost completed within a few minutes.

#Additive TI anti bloating test

Figure 4 Additive TI thermal storage test, (50 ° C&98RH%)

After one day of storage under high temperature and high humidity conditions, the gas collection bag containing blank samples has shown significant swelling; However, the gas collection bag with Additive Tl added showed no significant changes.

Additive Tl effectively removes moisture from the curing agent, giving it good storage stability.

Figure 5 Additive TI room temperature storage test (23 ° C&50% RH)

After four months, the isocyanate in the blank sample had already gelatinized. In the same situation, the isocyanate curing agent dehydrated with Additive Tl showed no significant change and had good storage stability.

Additive OF

Unlike Additive TI, Additive OF is a type of protoester compound that reacts gently with water without releasing any gas during the process. Suitable for most polyols and isocyanate components.

Figure 6 Physical properties of Additive OF

#Additive OF anti inflation test

Figure 7 Test of Additive OF under high humidity and high temperature conditions (50 ° C&98RH%)

After one day of storage under high temperature and high humidity conditions, the gas collection bag containing blank samples has shown significant swelling; However, there was no significant change in the gas collection bag after dehydration using Additive OF.

Additive OF can effectively inhibit the reaction between moisture and isocyanates in the curing agent, significantly improving the storage stability of the curing agent.

Figure 8 Additive OF room temperature storage test (23 ° C)

Four months later, the isocyanate in the blank sample had already gelatinized, while the sample with added Additive OF showed no significant change.

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Application Features

Additive TI and Additive OF have a stabilizing effect on polyurethane coatings. Recommended for use in single component and two-component polyurethane systems for dehydration environments of solvents, pigments, fillers, etc., it can achieve rapid and long-term dehydration.

Firstly, in the dispersion stage, Additive TI is added for rapid dehydration to remove the moisture brought by solvents, pigments, and fillers.

Secondly, in order to maintain the dry state of the system for a long time, an Additive OF long-lasting dehydrating agent is further added to ensure the stability of the polyurethane paint system and improve the quality and performance of the product.

Avoid direct contact between Additive TI and Additive OF to prevent their failure.

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The recommended dosage of Additive OF is 1-3% of the total weight of the coating. The exact dosage should be determined through experiments and related to the specific system.

As a stabilizer for single component moisture cured polyurethane systems, Additive Tl should be added before coating filling and filled after complete degassing; If the moisture content of the coating is 0.05-0.30%, add Additive TI in a ratio of 0.5-2.0% of the total formula weight, otherwise it will have a certain impact on the color.