Traditionally, most fillers were considered as a child category of additives because they affect nothing or even decrease the strength of the polymer.
Their main usage purpose is to reduce the cost of input materials by replacing expensive polymers. Besides, they probably fasten molding cycles. Other plastic properties could be changed, depending on which type of filler you are using.
Nevertheless, adding inorganic fillers can reduce mold shrinkage and thermal expansion.
I. Effects of fillers on plastics
Talking about reinforcing fillers, people discuss the shape, and surface chemistry... which is suitable for the goal of enhancing a polymer's mechanical properties.
Inorganic reinforcing fillers are stiffer than the matrix and deform less, and their particle-matrix interface leads to an overall decrease in the matrix strain in the vicinity of the particle.
Most manufacturers invest in developing the aspect ratio of reinforcing filler particles and enhancing their compatibility and interfacial adhesion. So they not only optimize the basic function but also improve additional functions.
Talc and asbestos fibers are the first generation of fillers as they have positive effects on PP heat resistance and stiffness.
However; asbestos affects people’s health. That’s why calcium carbonate particles and mica flakes are exploited after that.
Calcium carbonate increased PP homopolymers resistance, but not really optimized in increasing stiffness.
Mica increased stiffness and heat resistance better than talc did.
II. Classifications
Even though there are a variety of fillers, their common characteristic is that they are used at relatively high concentrations.
The table below demonstrates filler categories according to chemical family or their size, shape or their aspect ratio.
Calcium carbonate, mica, talc, kaolin are most commonly used particulate fillers.
Glass fibers are the most commonly used fibrous fillers.
Fillers can not be categorized by a particular function like additives. They are multifunctional and usually characterized by an essential function and some additional functions
| Primary functions |
Examples of fillers |
Additional functions |
Example of fillers |
| Modification of mechanical properties |
High aspect ratio: glass fibers, mica, nanoclays,carbon nanotubes, carbon/graphite fibers, andaramid/synthetic/natural fibers.Low aspect ratio: talc, CaCO3, kaolin, woodflour, wollastonite, and glass spheres. |
Control of permeability |
Enhanced permeability: stressconcentrators for inducing porosity:CaCO3 and dispersed polymersReduced permeability: impermeableplate-like fillers: mica, talc, nanoclays,glass flakes |
| Enhancement of fire retardancy |
Hydrated fillers: Al(OH)3 and Mg(OH)2 |
Bioactivity |
Bone regeneration: hydroxyapatite,tricalcium phosphate, and silicate glasses |
| Modification of electricaland magnetic properties |
Conductive, nonconductive, and ferromagnetic:metals, carbon fiber, carbon black, and mica |
Degradability |
Organic fillers: starch and cellulosic fibers |
| Modification of surface properties |
Antiblock, lubricating: silica, CaCO3, PTFE, MoS2, and graphite |
Radiation absorption |
Metal particles, lead oxide, and leaded glass |
| Enhancement of processability |
Thixotropic, antisag, thickeners, and acidscavengers: colloidal silica, bentonite,and hydrotalcite |
Improveddimensional stability.
Modification ofoptical properties
Control of damping Flake fillers, glass, and BaSO4 |
Isotropic shrinkage and reducedwarpage: particulate fillers, glassbeads, and mica.Nucleators, clarifiers, and iridescentpigments: fine particulates andmica/pigment hybridsFlake fillers, glass, and BaSO4 |
III. Market Demand
Global demand for fillers and reinforcing fillers are promising. Primary markets are building and construction, transportation, followed by customer products and appliances, furniture, industrial, electronics, and packaging. Calcium carbonate, talc, mica, kaolin, glass fiber, carbon fiber and carbon black for the plastics industry are the most used so far.
Heat resistance and flexural modulus are the 2 essential properties of plastics that are improved remarkably by adding performance minerals. Outdoor furniture, appliance components, automotive exterior parts are clear examples of how flexural modulus and heat resistance benefits plastic applications.
IV. EuP filler masterbatch
Over 10 years of experience, EuP has been regarded as one of the top 5 filler masterbatch manufacturers worldwide. At EuP, we deliver the various choices of filler masterbatch customized according to your requirements. Our filler masterbatches fit with PE, PP, HIPS, Bio, HD resins.
Our sales and R&D departments are willing to support you 24/7.