Expandable Microspheres

Lightweight filler and foaming agent for plastics, rubber and more

Expandable microspheres are hollow polymeric spheres each of which comprises a thermoplastic shell encapsulating liquid hydrocarbon. When heated to a temperature high enough to soften the shell, the increasing pressure of the hydrocarbon will cause the microsphere to expand, increasing the sphere volume by 80 to 100 times.

The density of microspheres after expansion can be lower than 30 kg/m3(0.03 g/cm3) which makes them an ideal lightweight filler and a foaming agent for all kinds of plastics and rubber.



Now more than ever, the world is pursuing lightweight, comfortable and eco-friendly solutions. For automotive and aerospace industries in particular, lower density materials that cut load and fuel consumption are a huge cost-safer. Besides, lower density often means less amount of materials required which is conducive to protecting natural resources.

The density of Crerax expandable microspheres is only 1/50 of that of water. Adding the microspheres to the original materials will significantly reduce the overall weight of your products. Take vehicles for an example, for every 10% weight reduction, the fuel efficiency can be increased by 6%-8%. That says, if we applied microspheres in the making of certain auto parts to bring the vehicle weight down by 100kg, the fuel consumption per 100 km could be reduced by 0.3-0.5L. Other contributions Crerax expandable microspheres do include preventing shrinkage and warpage in injection molding, lowering the permittivity of various materials, improving thermal insulation, and more.

Ultrahigh temperature thermoplastics (PP、PA、PC、PET/PBT、PPS)

Ultrahigh temperature thermoplastics (PP、PA、PC、PET/PBT and more)

Crerax ultra-high temperature expandable microspheres can be added to PP, PA, PC, PET / PBT and more where the injection temperature is above 230 ℃. Once added, the enhanced mobility of the melted plastics ensures that every inch of the plastics is heated evenly to prevent warpage. Given 65MPa injection pressure, 260C molding temperature and a 45-second cooling time, for instance, the density of a PC product decreases by 30% for every 2% addition of microspheres.

Shoe soles

Shoe soles

Traditional shoe materials are often bulky, easily cracked and worn out. Expandable microspheres used as a blowing agent bring the following benefits:
  • Less injection molding defects thus a higher yield
  • More easily molded with shorter curing time
  • A controlled foaming process
  • Making soles weigh less and be more comfortable on the foot
  • A modified surface as matt rubber with a brighter color, thus a better look and feel
  • Vehicle underbody coating (UBC)

    Vehicle underbody coating (UBC)

    A 400-1000 μm-thick layer of underbody coating adds 8.5kg to 9.5kg of extra weight to the vehicles. Microspheres used as a foaming agent tremendously decrease such weight without affecting the wear and corrosion resistance of the coating. More specifically, they:
  • Decrease weight by 50% but not thickness
  • Are non-toxic
  • Can be blended smoothly into the coating materials forming a uniform and closed cell structure
  • Improve sound and heat insulation
  • Artificial marble

    Artificial marble

    Certain chemical substances used in artificial marble can be harmful to health and make the products easily crack. Incorporating microspheres can help:
  • Reduce the risk of cracking or damage during installations
  • Lower freight and installation costs due to lighter weight
  • Enhance thermal shock resistance
  • Make grinding, trimming and drilling process easier
  • Make the products last longer
  • Take up less original raw materials, thus more eco-friendly
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    Surface Modification

    The addition of microspheres to printing inks is a simple and efficient way of surface modification. Varieties of surface could be achieve by adjusting the amount and size of the added microspheres without affecting the original process. Specifically, once the printing matter with microspheres be heated to a temperature at which the microspheres expand, the binder would crosslink, making different particle-sized microspheres result in different surface appearances and touching feelings. Usually small particle-sized microspheres bring a smooth surface while large particle-sized microspheres give a relatively rougher one. In addition, if the foaming process is properly controlled, it would be possible to achieve various surface effects through different foaming temperatures.

    Provided that microspheres are added to the printing ink as a foaming agent, and are printed on a surface of paper, non-woven fabric or textile by gravure or rotary screen, desirable surfaces like three-dimensional effect, velvet or suede surface would come into being. Besides, it also brings impressive tactility with anti-slip effect.



    The addition of microspheres can bring the following advantages to wallpaper:
  • Three-dimensional pattern effect
  • Velvet texture
  • Adding different particle-sized microspheres may result in different types of surface appearances and feels. Usually, small particle-sized microspheres bring a smooth surface while large particle-sized microspheres give a relatively rougher one
  • Printing paste

    Printing paste

    The addition of microspheres to the printing ink not only keeps print beautiful and everlasting, but also brings different types of tactility as well as the following advantages:
  • 3d effect printing
  • Strong adhesion and good wash fastness
  • Strong coverage with saturated color
  • Customized designs: low/medium/high velvet type, different foaming levels and degrees of temperature resistance
  • Leather repair

    Dermal repair

    The combination of expanded microspheres to the stucco coating or primer can repair leather damage due to scratches and streaks. The closed cell structure of the expanded microspheres is fine and uniform, which can help achieving remarkable repairing effect by making the leather surface glossy again. Microspheres offer the following advantages for dermal repair:
  • Excellent filling ability
  • Reduced shrinkage
  • Highly polished
  • Soft touch
  • Artificial leather

    Artificial leather

    Coating the expandable microspheres on PVC or PU artificial leather brings a tactility like suede. Other surface effects can also be realized should the amount and the particle size of microspheres be adjusted accordingly . Besides, microspheres bring the following properties to artificial leather:
  • Excellent elasticity
  • Air permeability
  • Soft feel
  • Polished surface
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    Thermal Insulation

    As people’s energy demand goes up, the efficiency of resources consumption and the solutions of resources saving have been drawing more and more attention in a wide range of industries. The microspheres are composed of a thermoplastic shell encapsulating hydrocarbons, which is expandable after heating and will form an inflatable closed cavity with good insulation.

    When added to polyurethane, phenolic resin, paint or other proper materials, excellent thermal insulation would be realized. According to statistics, only 1.5% expanded microspheres combined with the thermal insulation coating can effectively bring down the thermal conductivity by half. Under the global trend of energy saving, this advantage is of vital importance.

    As can be seen from the above diagram, as the volume of the microspheres in the coating increases, the heat insulating performance is improved. With such excellent heat insulation, expanded microspheres are widely used in coatings.

    Thermoplastic Vulcanizate (TPV) Sealing Strip

    Thermoplastic Vulcanizate (TPV) Sealing Strip

    Thermoplastic vulcanized elastomer (TPV) is the most commonly used seal material today due to its elasticity, recyclability and ability to be molded. Incorporating microspheres in TPV can effectively reduce the compression set of the materials and increase resilience.
  • Density reduced to be around 0.5 g/ cm3
  • Uniform and dense foaming cells invisible to the naked eye
  • Total costs of materials reduced
  • A stable and controlled foaming process that is less demanding of equipment and techniques
  • Sound and heat insulation and good cushioning effect
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    Resilience & Compressibility

    The microspheres are core-shell-like spherical particles with a thermoplastic polymer shell enveloping gas, which can be compressed under pressure, but can be easily restored to the original size after the pressure released. That accounts for its impressive resilience and thus could be applied in various fields including but not limited to thermoplastic materials as thermoplastic elastomers or rubber.

    Besides, vehicle underbody coating (UBC) added with microspheres shows higher resistance against gravel; TPV sealing strip combined with microspheres shows less transmogrification against compression; wine corks containing microspheres gain stronger elasticity and thereby present better tightness.

    Wine cork

    Wine cork

    The traditional wine corks are expensive, and the particles of the corks can easily go into the wine and affect the taste and smell. In a long run, it is also likely that the wine inside the bottle causes the corks to stiffen and lose the sealing effect. Incorporating the microspheres allows corks to have excellent compressibility and resilience which ensure an extremely good sealing performance. The uniform and closed cell microspheres enable a controlled foaming process. Microspheres’ low liquid absorption and permeability spare corks being affected by the wine inside.

    EPDM non-porous rubber strips

    EPDM non-porous rubber strips

    Used as a foaming agent for EPDM foam rubber, microspheres can change many nonpreferred results that chemical foaming process creates including large-sized and nonuniform foam cells and undermined mechanical properties. Microspheres can also be applied for Non-porous rubber to:
  • Achieve a micro foaming process
  • Only create uniform and dense foam cells invisible to the human eye
  • Reduce density
  • Reduce weight
  • Improve sound and heat insulation performance
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    Improve Structure & Space

    Unexpanded microspheres can be used as a foaming agent. When heated, the microsphere polymer shell softens and the inner seal of the hydrocarbon vaporizes, enabling a controlled foaming process. The expanded uniform and closed cell microspheres improve the material structures and create many other excellent properties.

    paper/cardboard/paper plastic

    paper/cardboard/paper plastic

    The traditional materials used in paper do not always ensure such properties as high bending stiffness, high tearing strength or heat insulation. On the other hand, incorperating Crerax expandable microspheres in the materials can significantly enhance those properties - and more:
  • Increases paper thickness and density and creates soft feel
  • Increases paper stiffness without adding extra weight
  • Better thermal insulation as well as anti-slip
  • Less amount of raw materials needed thus lower production costs
  • Emulsion explosive

    Emulsion explosive

    Adding expandable microspheres enables the density of emulsion explosives to be adjusted and improves sensitivity in initiaticxi. Other characteristics include:
  • Microspheres act also as a reducing agent in detonation
  • Good storage stability under various climatic conditions, and a lengthened storage period
  • Increased compressive strength of the explosives
  • Lightweight cement

    Lightweight cement

    Expandable microspheres create voids in cement before it solidifies, thereby improving its frost resistance and durability. Additionally, the expanded microspheres tremendously take up volume in which case much less cement is needed to achieve the same overall volume as that without the expandable microspheres being added. Certainly, less cement means less costs. Besides, cement after incorporating expandable microspheres has higher compressive strength.



    Coremat is an adhesive-bonded polyester fiber/glass fiber material in which expandable microspheres are embedded. As a lightweight material, coremat has been widely used in wind turbines, ships, auto parts, theme park facilities, ceramic plumbing fixtures and more. Its main features are as follows:
  • Good compression resistance and elasticity that lead to dimensional stability
  • Low density
  • Volumized without extra weight added
  • Hollow ceramic

    Hollow ceramic

    Expanded microspheres can be blended thoroughly into the ceramic materials. When the high-temperature sintering process begins, the shells of microspheres break to form interpenetrating micro-pores in the ceramics. Microspheres guarantee uniform and controlled pore sizes in the porous ceramics, as well as:
  • Cause a high percentage of increase in pore volume
  • Reduce cracking and deformation during the sintering process
  • Enable the control of porosity and pore structure of porous ceramics
  • Reduce density of the products