Carbonate Recycling in Polyvinyl butyral (PVB) Carpet Backing
At least one company (www.tandus-centiva.com) has developed a fully recyclable, filled backing, based on the thermoplastic polymer PVB. This polymer is sourced from the recovered interlayer in safety glass such as postconsumer vehicle windscreens, further adding to the eco-credentials. The high filler loading (a mix of calcium carbonates and aluminum hydroxide) is automatically recycled in this product.
Talc Recycling in Polyolefins
The main polymer use for talc fillers is in thermoplastic compounds for the automotive industry, and it is believed that these compounds have a high recycling rate. Many of the major automotive markets have stringent environment targets which encourage recycling. Thus, in the EU, the End of Life Vehicle Directive requires that a minimum of 95% of a vehicles weight must be reused or recycled. Talc-filled thermoplastics are recovered and reused for a variety of automotive applications, mainly in under bonnet parts, body arch liners, and cable harness parts. There is also down-cycling into nonautomotive parts such as water and sewage pipes, furniture feet, etc. According to the Industrial Minerals Association (Ima-europe.eu), about 95% of the talc used in automotive applications in Europe is recycled in some way.
Surface Modification and Coupling Agents
Filler surface modification is widely used for improving the processing and properties of composites and will be equally important for recycled and sustainable fillers. In most cases, these additives will be the same as used with the virgin filler of the same composition. In a few cases, such as natural products like wood, new types of treatment are being developed, such as maleated polyolefins. The most extreme case is for particulate organic fillers, such as lignin, intended for use in tire applications. These products are still in their infancy, with little published detail.