Coatings & Construction / Solution Family

Mineral Fillers & Extenders

Calcium carbonate extenders and titanium dioxide opacity u2014 the filler and pigment package that controls hiding, film build, and cost in architectural and industrial coatings.

Overview

Mineral fillers and extenders are the particulate solids that give a coatingnopacity, film build, and lower cost per gallon. They split into two roles: annopacifying pigment u2014 titanium dioxide, which scatters light and does the hiding u2014nand extender pigments such as calcium carbonate that occupy volume at a fractionnof the price. A workable formula uses both. Specify titanium dioxide for hiding power, thenncarry the pigment volume with extenders sized to the finish you need.

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Titanium dioxide is usually the most expensive raw material in a paint formula, sonextender and spacing strategy drives cost more than any other pigment decision. Calciumncarbonate is the standard extender: it fills volume, supports the film, and lets anformulator hold hiding while trimming titanium dioxide content. The honest trade-off isnopacity. Replace too much titanium dioxide with low-refractive-index extender and hidingnfalls off, so balance the swap against the contrast ratio your spec requires.

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Calcium carbonate carries most extender duty across primers, fillers, and architecturalnpaints, while zinc oxide serves as a multifunctional white pigment where formulators wantnadded function alongside color. Filler loading itself is the second trade-off. Raising thenpigment volume concentration cuts material cost, but above the critical PVC a film can losengloss, scrub resistance, and durability. Set loading against the gloss and exposure targetnfor the finish rather than cost alone, and confirm any regulatory status for your market.

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Where it's used
  • Architectural and decorative paints needing hiding power at a controlled cost per gallon
  • Primers, sealers, and fillers where extender pigments build film and volume
  • Interior and exterior wall paints balancing titanium dioxide content against opacity
  • Texture coatings, putties, and joint compounds using calcium carbonate as bulk extender
  • Industrial and trade finishes where pigment volume concentration is tuned to a gloss target
Frequently asked questions
What mineral fillers and extenders does RawSource supply for coatings?
For coatings, RawSource sources calcium carbonate (the primary extender pigment), titanium dioxide (the opacifying white pigment for hiding), and zinc oxide (a multifunctional white pigment). All are available in bulk with CAS and documentation for RFQ.
What is the difference between an extender pigment and an opacifying pigment?
An opacifying pigment such as titanium dioxide scatters light and provides hiding power. An extender pigment such as calcium carbonate has a low refractive index, so it contributes little hiding; it fills volume, builds film, and lowers cost. Most coatings use both.
Can calcium carbonate replace titanium dioxide to cut cost?
Partly. Calcium carbonate and other extenders carry pigment volume and let a formulator trim titanium dioxide, the most expensive raw material in the formula. Because extenders have a low refractive index, substituting too much reduces hiding. Balance the swap against the contrast ratio and pigment volume concentration your specification requires.
Is titanium dioxide subject to regulatory restrictions?
Titanium dioxide is the subject of regulatory attention in some jurisdictions, including the classification of certain powder forms and restrictions on some uses. Confirm the current regulatory status for your jurisdiction and application before specifying.
Disclaimer. Information on this page is provided for general reference and compiled from authoritative public sources (e.g. PubChem/ECHA). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot you purchase governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim. Always consult the current Safety Data Sheet (SDS) before handling, and confirm regulatory status, classification, and suitability for your application and jurisdiction.
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