Nanjing Chemical Material Corp.
China expandable microsphere's Full name is thermoplastic expandable microspheres. These are thermally expandable micro capsules with a core-shell structure, consisting of a shell of thermoplastic polymer encapsulating a low-boiling point solvent (liquid hydrocarbon gas or other compounds). Their diameter is usually between 10~50μm. When heated, their volume can rapidly expand to several times their original size and, after cooling, they can maintain the expanded volume without shrinking back. China expandable microspheres are ideal lightweight fillers and physical foaming agents, and have been widely used in coating printing, foam industry, textile industry, construction, automotive manufacturing, aerospace, etc.
Expansion Principle
At room temperature, the shell of the microsphere is hard. When the microsphere is heated, as the temperature rises, the liquid hydrocarbon gradually vaporizes, increasing the internal pressure of the sphere. When the temperature rises to the glass transition temperature of the polymer shell, the shell softens, and the microsphere begins to expand due to the pressure difference between the inside and outside until the pressure inside and outside the sphere reaches a balance, at which point expansion stops, achieving the maximum foaming state. If heating continues, the mechanical strength of the polymer shell decreases, causing the microsphere to shrink and rupture, releasing the gas inside the shell.
Three-Dimensional Printing Patterns
Due to the excellent foaming properties of China expandable microspheres, when added to printing ink or paint, they can achieve controllable foaming by controlling the particle size of the microspheres and the expansion temperature. Different particle sizes of microspheres can bring different surface appearances and tactile sensations, thereby obtaining three-dimensional effects, special velvet surfaces, suede effects, and frosted touches. They are widely used in ink printing, fabric dyeing, Braille embossing, wallpaper, leather, etc.; they can also be added to anti-slip agents, coated on the surface of paper, non-woven fabrics, textiles, etc., to make anti-slip mats, carpets, corrugated paper, etc.
Lightweight Materials
China expandable microspheres, as ideal lightweight fillers for plastics and rubber, and with good resilience, are applied in extrusion or injection foaming of thermoplastic materials such as PE, PP, PVC, PET, TPR, TPU, etc. They can increase product volume, improve insulation performance, reduce density, and enhance heat resistance and compressive strength. They are widely used in wine bottle stoppers, automotive parts, lightweight clay, foamed shoe materials, foamed rubber, sealing strips, cables, tires, artificial marble, porous ceramics, emulsified explosives, and other industrial production.
Functional Coatings
China expandable microspheres can be added to corresponding coatings to act as protective layers, giving the product certain elasticity and resilience, impact resistance, and other special properties. For example, they can be used in automotive underbody armor paint to reduce the weight of the car chassis by 50%, while improving its corrosion resistance and reducing noise, significantly lowering fuel consumption and costs. They can also be used in leather coatings, clothing linings, automotive interiors, anti-crack agents, and fire-resistant coatings.
Adhesives/Thermal Release Tapes
In many application fields, different materials need to be combined and separated. By adding thermally expandable polymer microspheres to adhesives, thermal release at connection points can be achieved. Thermal release tapes have adhesive power under normal conditions; once heated, the adhesive power disappears, allowing for easy removal without damaging components, making them widely used in the electronics manufacturing field.
Semiconductor CMP Polishing Pads
China expandable microspheres can be used to make CMP polishing pads. CMP technology is a process that achieves the required surface flatness of polished materials through the combined actions of chemicals and mechanics, with the polishing pad being an important component.
