Engineering plastics such as TPU, PET, PA (Nylon), and PC are the backbone of modern industry due to their strength and thermal stability. However, processing these materials is a thermal challenge, often requiring temperatures exceeding 250°C.

Under these extreme conditions, standard lubricants like Paraffin Wax or regular PE Wax fail catastrophically—they smoke, degrade, and migrate, ruining surface finish.

Historically, Montan Wax has been the gold standard for these applications due to its high polarity and heat resistance. However, relying on a finite mineral resource comes with risks: soaring costs, supply shortages, and batch-to-batch inconsistencies.

This brings us to the modern solution: Synthetic Polyester Wax. It replicates the molecular structure of Montan Wax but eliminates its natural limitations.

 The Thermal Challenge: Why Standard Waxes Fail?

Processing engineering plastics requires additives that can survive severe thermal stress inside an extruder.

• The Problem: Materials with inadequate thermal resistance (like Paraffin) degrade at 250°C+, producing gases and carbon residues. This leads to mold fouling and weak mechanical properties in the final part.
• The Need :Manufacturers need a lubricant that offers high flow without degradation—a role traditionally filled by Montan Wax, but now more efficiently served by high-performance Polyester Wax.

Why Polyester Wax is the Superior Solution

Polyester wax has emerged as the premier high-performance lubricant for engineering plastics. Its ester-based structure provides inherent thermal stability, allowing it to withstand temperatures above 250°C with minimal weight loss.

Key Advantages Over Traditional Options:

• Paraffin/PE Wax: Superior compatibility with polar resins (PA, PC, PET) and significantly higher thermal stability.
• Natural Montan Wax: Polyester wax provides the same lubrication performance but with better color stability, higher purity, and zero supply chain risk.

It functions as a dual-action lubricant:

• Internal Lubrication:Reduces melt viscosity and shear heat, improving flow rates.
• External Lubrication: Prevents sticking to metal surfaces, reducing equipment wear and extending screw life.

1.1.1. Product Spotlight: RLWAX® RL-691A – The “Synthetic Montan” Equivalent

Rallychem’s RLWAX® RL-691A is engineered to be the definitive alternative to natural Montan waxes.

Technology & Composition
Utilizing  Advanced Synthetic Ester Technology, RallyChem precisely replicates the long-chain ester structure found in premium natural waxes. Unlike mined products, this controlled synthesis guarantees a material free from unstable impurities.

Performance Breakthroughs:

• Ideal for Polar Resins: Perfectly compatible with PA, TPU, PET, and PBT.
• Superior Thermal Stability :Remains stable well beyond standard processing temperatures, ensuring no smoke or volatile emissions during injection molding or extrusion.
• Batch Consistency :Being fully synthetic, RL-691A eliminates the quality fluctuations inherent in natural mineral waxes, ensuring predictable results every time.

Conclusion

For high-temperature engineering plastics, the industry is shifting from finite mined resources to advanced synthetics.

Polyester wax (like RL-691A) offers the perfect synergy: it matches the high-performance standards of Montan wax while solving its supply volatility and cost challenges. By partnering with a specialized manufacturer like Rallychem, producers can achieve consistent quality, reduce downtime, and secure their formulations against raw material scarcity.

Rallychem | Innovating Polyester Wax Solutions for High-Temperature Engineering Plastics