We try to deliver on our value proposition “Efficiency – Made in Germany” by providing real customer value – day in, day out. Every day our team of experts works to improve the product portfolio for our customers and to expand the range of applications. NOBELMIN GmbH is equipped with special laboratories to test the properties of talc in many different uses, to support customers in selecting the right talc quality, or to develop new opportunities for the use of talc.
Close cooperation with end customers helps to speed up the process and create added value for our clients. Thanks to our sophisticated manufacturing and preparation processes, we produce talc in its purest and most effective form. This also enables us as NOBELMIN GmbH to develop innovative products for previously undiscovered applications.
Example: Polylactic acid
A typical biodegradable thermoplastic synthesized from renewable raw materials such as corn, cassava, sugar cane or sugar beet pulp.
Comparable to polypropylene, polylactic acid also has significant potential for optimization in terms of cost and application properties through the addition of filler pigment and nucleating agent.
Polylactic acid (or PLA – PolyLactic Acid), for example, is the most important biopolymer and is already available industrially in large quantities on the global markets.
PLA is a typical biodegradable thermoplastic synthesized from renewable raw materials such as corn, cassava, sugar cane or sugar beet pulp. The flexural modulus of PLA is higher than that of polystyrene, and PLA exhibits good thermal conductivity.
PLA polymers range from amorphous glassy polymer to semi-crystalline and highly crystalline polymer with a glass transition of 60-65 °C and a melting temperature of 130-180 °C. However, pure PLA from production is mainly in amorphous state, its product properties and especially its thermal resistance are insufficient under these conditions.
The addition of highly micronized talc products leads to a 50-60% reduction in crystallization time at a talc loading of 15-20%. At the same time, the flexural modulus is significantly improved. Increasing the talc loading rate leads to a linear increase in gain.
As a side effect, improvements in melt strength and reduced strand breakage during cooling and pelletizing were also observed.
Example: Expanding the product properties of PLA
A large number of trials have already been conducted to investigate and improve the possibilities for product optimization in PLA through formulation and compounding with talc…
Results are available, but there is still a lot to do.
Impact strength remains above that of pure PLA even at 20% talc loading.
Despite the properties achieved, a large number of optimization steps are still required, especially in terms of the comparability of the functionalities with existing fossil-based products. Nobelmin will continue to participate in these developments from the talc filler side in order to sustainably advance the replacement of fossil raw materials.
By adding micronized talc as a highly efficient nucleating agent, the crystallization of PLA can be accelerated, so that the mechanical properties are also improved.
The 50% crystallization rate was reduced approximately by a factor of three by using a synergistic combination of plasticizer, nucleating agent and talc
The addition of talc to PLA formulations leads to a significant increase in impact strength initially – up to 3-4% – followed by a more gradual decrease at higher talc loadings
It also significantly increases the heat deflection temperature (HDT).
The HDT of crystallized PLA increases almost linearly with the talc loading.
By using a synergistic combination of plasticizer, nucleating agent and talc, impact strength can also be adjusted to maintain good HDT performance at the same time.
Lamellar talc grades show a significantly greater effect on HDT. Adding 8-10% talc to PLA also helps maintain dimensional stability of parts.
A talc addition rate of 5 to 6% resulted in the best impact strength values.
Such a combination resulted in a reasonable compromise between HDT, crystallization and impact strength.
The addition of up to 20% of high aspect ratio talc significantly reduced oxygen and water vapor permeability (known to be poor in PLA for many applications).
Example: compostability of talc-filled bioplastics
NOBELMIN MinTalc can be used without restrictions in compostable biopolymer formulations, so that the products continue to comply with the European standard EN 13432. Recommended talc grades from NOBELMIN GmbH are, for example, MinTalc 9703HP and MinTalc 9715.
For the labeling and certification of plastic products with the designation “compostable”, their compostability must be successfully demonstrated in accordance with the harmonized European standard EN 13432 or EN 14995.
These two standards define the technical specifications and the test procedures also for testing the compostability of bioplastic products.
If necessary, proof must also be provided for certification of 100% organic products (e.g. untreated wood).
The requirements for the certification of packaging that can be broken down by composting and biodegradation have been laid out accordingly in the
EN 13432: 2000 packaging
This is a harmonized European standard in conjunction with the European Directive on Packaging and Packaging Waste (94/62/EC), which is valid in all European Member States (source: The Biology Notes).
NOBELMIN MinTalc can be used without restriction in compostable biopolymer formulations, so the products still comply with the European standard EN 13432. Recommended talc grades from NOBELMIN GmbH are e.g. MinTalc 9703HP and MinTalc 9715.
There are still several challenges for the further expansion of bioplastics today:
Cost reduction is a key aspect
The production of bioplastics is currently still about ten times more expensive than that of conventional polymers.
Recycling processes need to be converted and expanded
The recycling systems currently in place are not yet capable of separating bioplastics for recycling and returning them to the reusable materials circuit.
Product development and functionality do not yet comprehensively meet the requirements of existing production and packaging facilities
The existing requirements for plastics, (the functional diversity and variability of petroleum-based polymers) cannot yet be achieved with plastics based on renewable raw materials – at least not everywhere and not yet in a cost-efficient manner (tensile strength, stretchability, sliding properties, barrier functionalities, etc.).
NOBELMIN GmbH supports the market development for bioplastics and supplies talc to improve the quality of these polymer products.