Xintao sincerely invites you to explore activated molecular sieve powder solutions for extending the curing time of polyurethane adhesives and optimizing construction efficiency. From September 17 to 19, 2025, the 28th China International Adhesives & Sealants Exhibition will grandly open at the Shanghai New International Expo Center. Xintao will showcase its full range of powdered molecular sieve products and cordially invite all new and existing customers to visit booth W2372.
About Exhibition
At the exhibition, Xintao will showcase a comprehensive range of activated molecular sieve powder products to meet diverse needs, including 3A, 4A, 5A, and 13X activated molecular sieve powder, as well as modified activated molecular sieve powder. Specifically, Xintao’s powder molecular sieve, with their efficient adsorption properties, effectively extend the curing cycle of polyurethane adhesives, addressing the critical issue of “difficulty controlling curing time” during polyurethane adhesive production and application. This feature prevents quality issues such as uneven adhesive layers and residual bubbles caused by over-curing, while also allowing ample time for application, ensuring efficient application and ultimate bonding performance.
Controlling the curing time is crucial in the production of polyurethane adhesives. If the curing time is too short, it can lead to poor product quality, reduced production efficiency, and substandard performance. While conventional zeolite powder molecular sieve effectively absorbs moisture and eliminate bubbles, their strongly basic hydroxyl groups can accelerate the polyurethane crosslinking reaction, resulting in a shorter curing time and posing challenges in the production process. Xintao’s 5A modified activated molecular sieve powder offers an innovative solution to this problem.
To ensure customers have a thorough understanding of product application logic and practical solutions, Xintao will have a dedicated team of sales, technical, and R&D representatives stationed at the booth throughout the exhibition. Focusing on “professional answers + efficient solutions,” we will help customers overcome the challenges of polyurethane adhesive curing control. Xintao sincerely invites customers to visit us for discussions and explore the potential of powder molecular sieves in the polyurethane adhesive industry.
How It Works
One of the core curing reactions of polyurethane adhesives is the reaction of isocyanate groups (-NCO) with water to form amino groups (-NH₂). These amino groups further react with remaining isocyanates to form urea bonds (-NH–CO–NH–), ultimately forming a crosslinked network that enables curing. The chemical reaction can be expressed as follows:
① –NCO + H₂O → –NH₂ + CO₂↑
② –NCO + –NH₂ → –NH–CO–NH– (urea bond)
Xintao powdered molecular sieves have a high specific surface area and strong adsorption capacity. When added to polyurethane adhesives, they do not chemically react with components such as polyols, isocyanates, and plasticizers. Instead, they selectively adsorb trace amounts of water, significantly reducing the concentration of water available to react with isocyanates. When water is adsorbed and blocked from the reaction system by the molecular sieve, the crosslinking reaction between isocyanate and water is significantly slowed, delaying the overall curing process and extending the working time. Furthermore, the reaction between water and isocyanate suppresses the production of carbon dioxide, thereby preventing the formation of bubbles.
5A Modified Molecular Sieve Powder: The Preferred Additive for Extending the Curing Time of Polyurethane Adhesives
Xintao 5A Molecular Sieve Powder (Ordinary)
5A molecular sieve powder is a white powder with a size of 2-4 microns. It has a static water adsorption rate of ≥25%, a packaged water content of ≤0.5%, and a pH of 10.5-11.5. It effectively absorbs moisture from polyurethane adhesives, preventing it from reacting with isocyanate (-NCO) groups to produce CO₂ bubbles. While it is highly effective in removing water, its inherent alkalinity accelerates the curing reaction and shortens the adhesive’s curing time.
Xintao 5A Modified Molecular Sieve Powder
To address the shortcomings of ordinary 5A molecular sieve, a special surface modification process has been used to adjust its surface chemical properties, significantly reducing its surface alkalinity and achieving a pH of 9.8-10.2. Laboratory testing has shown that, at the same addition level, modified 5A activated molecular sieve powder not only removes water and eliminates bubbles, but also increases the curing time of polyurethane adhesive by 40-60 minute, providing a longer working time, smoother application, and more stable and superior product performance. Furthermore, it can adsorb gases such as carbon dioxide and hydrogen sulfide generated during the production process in specific polymers.
Xintaoke’s modified 5A molecular sieve powder is a dewatering powder developed specifically for the polyurethane industry. Through innovative materials science, it retains the excellent adsorption properties of standard 5A molecular sieve while effectively reducing its accelerated curing effect, thus resolving the industry challenge of controlling the curing time of polyurethane adhesives.
Contact us
Jiangxi Xintao Technology Co., Ltd.
Address: Shangxian West Road, New Third Board Industrial Park, Pingxiang Economic and Technological Development Zone, Pingxiang City, Jiangxi Province
Website: www.xtadsorbents.com
Email: export@xt988.com
