LiMeOx – Monoterpene ester oxides as biobased plasticizers for polymers

Initial situation

With about 10 million tons annual consumption, plasticizers are one of the most important additives in the plastics industry. Most common are esters of phthalic acid (e.g. dioctylphthalate, DOP) as they possess an outstanding plasticizing effect at low costs; about 80 percent of all used plasticizers are phthalic acid derivatives.

However, biobased alternatives for phthalates have shifted into the industrial focus within the last years. In addition to foregoing fossil oil, the toxic effects of phthalic acid derivatives for humans (endocrine disruptor) and the environment were decisive – resulting in a prohibition in distinctive markets (medical devices, toys, in particular in the USA and Canada). Therefore, the comparably high tendency for migration of phthalates (leaching) caused, among other things, by their low molecular weight.

Challenges

One approach to avoiding phthalates and improving the environmental performance of plastics in general is to use biobased plasticizers, which reduce the use of fossil feedstocks and have potentially higher biodegradability. Typical disadvantages of biobased plasticizers so far are higher prices, complex production, insufficient raw material base and poorer performance.

Objectives and solution approach

The overall objective of the LiMeOx project is the synthesis of a new family of plasticizers based on monoterpenes as a replacement for phthalic acid esters. The chemical structure of the target molecule should combine the positive properties of industrial fossil and bio-based plasticizers. The plasticizers obtained in this way should consist of at least 80 percent renewable raw materials. Right from the start, the syntheses are to be designed both ecologically and economically. The target polymers are PVC (main market for plasticizers) and biopolymers with high additive requirement (PLA, PHB).