The egg, nature’s own construction material is our guiding star at GAIA. 90 % of the egg is calcium carbonate. Based on the principles of the egg we developed Biodolomer®, a high-quality mineral filled biodegradable compound and patented construction material. Our technology utilizes the benefits of calcium carbonate minus the increased wear and tear usually associated with mineral filled plastics. Let’s look at calcium carbonate as a renewable raw material and the known and potentially new benefits of introducing calcium carbonate to an enzyme enriched PLA-based packaging compound like the new Biodolomer® compound developed for the SISTERS-project.

Calcium Carbonate, a renewable raw material

4 % of earth’s crust is made of calcium carbonate, making it one of the most common raw materials in nature. Calcium carbonate is constantly replenished by means of natural cycles in rivers, lakes & oceans or formed as minerals in the form of shells, skeletons, stalactites, and stalagmites. Commercial grades of calcium carbonate are mostly produced from natural sources such as limestone, chalk or marble which are widely available around the world. In addition, new bio-based calcium carbonates from egg- and seashells have recently gotten to a price point and quality to rival the proven resources.

The results of two recent independent university studies conclude that the annual replenishment of calcium carbonate varies from 8.8 to 14.5 billion tons/year in different environments. The annual consumption of calcium carbonate in various markets (infrastructure, cement,…) being in a range of 4.5 Billion t/year, the replenishment rate (according to the ISO 14021 definition) exceeds the consumption rate.

Therefore, calcium carbonate meets the criteria for a renewable material.

In addition, the footprint of extracting and processing calcium carbonate is low as shown by life cycle inventory data compiled by CCA-Europe. LCA studies made on Biodolomer® compound thru the years also supports this, the more calcium carbonate we use, the lower overall carbon footprint.

*Source IMA Europe, Brussels

General benefits

  • Calcium carbonate is used to counteract acidification. That is why calcium carbonate is spread over fields, lakes, and forests to neutralize the pH value.
  • Calcium carbonate improves the compost, raises the pH interval and supply plant life with calcium and magnesium to increase the growth potential.

Benefits of using calcium carbonate in PLA based compound like Biodolomer® for the thermoform process.

  • Increased stiffness
  • Down-gauging potential

  • Higher extruder output in sheet extrusion & thermoforming
  • Lower shrinkage

  • More isotropic physical properties
  • Improved forming accuracy

The high thermal conductivity of calcium carbonates allows to speed up extrusion, sheet processing and thermo-forming. Rigid calcium carbonate particles lead to more isotropic physical properties, lower shrinkage, and improved forming accuracy.

Enzymes + calcium carbonate may broaden the use of PLA-based compound?

Part of the SISTERS project aims to demonstrate by introducing enzymes in the extrusion processing together with Biodolomer® and other pure PLA blends may boost the disintegration speed of the packaging material at ambient temperatures. First biodegradation results indicate a quicker biodegradation effect with Biodolomer® compared with pure PLA blends. This may be due to the calcium carbonate present in Biodolomer. We could potentially use calcium carbonate to fine tune the biodegradation time of PLA-based packaging solutions without sacrificing the mechanical properties of the product.  PLA + calcium carbonate + enzymes could be one answer to successfully provide home compostable packaging solutions for the products mandated by the European Commission.