Expancel Microspheres Revolutionary Lightweight Fillers and Blowing Agents in Foot Wear Industries and Many

Vinodhini Harish

10 May 2024

We have seen several innovations in polymer shells in recent times. There are solid reasons why this is so. Every industry is thriving to reduce weight, yet looking for durability, structural integrity, strength, protection and resistance. Especially footwear, automotive and packaging industries are looking for cost-effective solutions with all the characteristics just mentioned. In this article, we have taken some time to appreciate the innovation of polymer shells and how they function as lightweight fillers and blowing agents. If you are inclined towards knowing how polymer shells are engineered across various industries, you will love this quick read. Let’s begin.

For the longest time, industries have been using latex sap rubbers. They are considered one of the earliest known polymers used by humankind. Then it was Bakelite which was considered the earliest synthetic polymer which exhibited both stability and heat resistance. Thus it was intensively used in the manufacturing of electrical insulators, telephones and other products. With the advancement in technologies, there have been quite several new polymers brought into the world of manufacturing sectors. They come with diverse properties and applications and cater to different requirements of mankind.

Some notable examples include: conductive polymers are used in applications such as flexible electronics and sensors, self-healing polymers are deployed in coatings, adhesives and other applications, bio-degradable polymers are used in sustainable alternatives to traditional plastics, shape memory polymers are used in manufacturing of biomedical devices and others.

In that order, Nouryon, a specialty chemicals leader involved in manufacturing everyday products such as personal care, paints and coatings, agriculture and food, pharmaceuticals, building products and cleaning goods has developed Expancel WB microspheres for white shoe soles. The organization has announced its launch at the Chinaplas exhibition in Shanghai, China this year. The primary purpose of this article is to celebrate the innovation and spread the word further.

Expancel microspheres and impressive features:

Shoe manufacturers are witnessing increasing demand for white shoe soles, and strong consumer interests without compromising on their performance or comfort. These Expancel microspheres are used across various applications such as the automotive industry and packaging.  
Now in the context of shoe manufacturing, Expancel microspheres are used to achieve the following benefits:
  • Weight reduction: The Expancel microspheres are critically small, and hollow spheres typically ranging from 10 to 100 microns in diameter. The material is a thermoplastic shell which is flexible, thin and lightweight. These microspheres encapsulate gas and expand when the gas inside expands. The shoe manufacturers incorporate these expancel microspheres into their sole material with the intent to reduce the overall weight of the shoe. This feature is very useful in “athletic shoes” where the lighter shoes improve the performance of the athlete.
  • Foaming effect: Shoe manufacturers are after the comfort and customer satisfaction of the wearers. The foaming effect of these microspheres creates a cushioning or foaming effect in the soles of the shoes. This aspect greatly contributes to the comfort of the wearer and reduces the fatigue of the wearer especially during long periods of walking or standing. You may wonder how this works, it’s because the manufacturers of the shoes mix these microspheres into the sole material during the manufacturing process. Since these are evenly dispersed throughout the material, it enables uniform expansion. Likewise, the heat produced during the manufacturing process affects the temperature-sensitive shell softens the material and makes it more flexible.
The temperature causes the gas inside the microspheres to expand rapidly and the pressure causes the microspheres to stretch and deform. This creates a foaming effect within the material.
What happens next? Since the microspheres are evenly dispersed along with the material, it creates a network of interconnected bubbles or voids within the material, and this structure helps to reduce the density of the material, making it lighter and more flexible. Once the desired sole shape is obtained, the material is allowed to cool and solidify.
The thermoplastic shell of the microspheres hardens trapping all that expanded gas inside the bubbles and forming a stable foam structure.
  • Enhanced appearance: These tiny microspheres enhance the whiteness and brightness of the shoe soles. Every consumer is after whiter shoe soles and shoe manufacturers are looking for solutions to cater the consumer demand. Overall whiter shoe soles help in obtaining a cleaner and more attractive appearance.
  • Density control: The microspheres are incorporated into the shoe soles during the manufacturing process; therefore, the manufacturers can easily adjust the amount of microspheres used in the sole. Thereby allowing the manufacturers to customize the level of cushioning and support.

Other applications of these microspheres:

Automotive industries are looking for lightweight solutions. Since reducing weight contributes very well to the fuel efficiency in vehicles, these microspheres could be a great advantage in the areas where weight reduction is important.

Likewise, there are areas where strength and durability play a major role. These polymer shells can be engineered to be strong and durable with the intent to offer higher protection and structural integrity.


The polymer technology has led to the development of shells with rich characteristics such as improved flexibility, resistance and thermal stability. These innovations have improved the overall performance of the products and contributed to various applications. Overall, the expancel microspheres are the perfect solution for applications where there is a demand for lightweight, durable, customizable, environmentally friendly and cost-effective materials.

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