Achieve Reliable Bonding with VDI-Tested TPEs 

Achieving durable and reliable adhesion between different materials is a cornerstone of modern product design, especially in applications where flexibility meets structural integrity. One such pairing is Thermoplastic Styrenic Elastomers (TPS) and nylon (polyamide, or PA), commonly used in automotive, consumer, and industrial components. At KRAIBURG TPE, we understand that successful bonding is not a matter of chance but the outcome of thoughtful formulation, optimized processing, and standardized testing. In this article, we explore the critical factors that contribute to strong TPS-to-nylon bonding and how we validate performance using proven industry methods. 

What Makes TPS-to-Nylon Bonding Successful? 

Strong bonding between TPS and nylon doesn’t just happen by chance—it’s the result of optimized material chemistry, precise processing, and reliable testing. At KRAIBURG TPE, we combine all three to ensure consistent, high-performance results. 

Key Factors Influencing Bonding Performance: 
 

• Adhesion-modified polymer composition: The precise chemical formulation of THERMOLAST® K AD/PA, AD/PA/CS, VS/AD/HM, and THERMOLAST® R RC/AD/PA series promotes excellent bonding performance with PA substrates. 
• Surface energy considerations: Clean, prepared nylon surfaces to enhance adhesion. 
• Tool temperature: For the best results, maintain tool temperatures around 50 °C as specified in processing data sheets. 
• Melt temperature: Process THERMOLAST® K series between 200 °C to 250 °C to achieve optimal flow and bonding characteristics. 
• Pre-drying: Properly drying the materials minimizes moisture-related defects and ensures consistent part quality. 

But how do we know if the bonding is strong? That’s where adhesion testing comes in. 
 

How Do You Measure Bonding? The VDI 2019 Bonding Test 

At KRAIBURG TPE, we test bonding performance using a two-component injection molding adhesion test based on the VDI 2019 standard.

 
Test Method Overview: 

• A thermoplastic base (150 x 60 x 2 mm) is overmolded with a TPE strip (150 x 20 x 2 mm). 
• The sample is tested using standard tensile testing equipment. 
• The peel force is measured at a constant 90° peel angle and correlated with peel path length to account for the TPE’s elasticity. 
• The TPE strip is mounted to the upper fixture, and the thermoplastic base to a sliding lower fixture, allowing for accurate peel force measurement. 
   

What Is Considered “Good Bonding”? 

Bond strength is typically expressed in N/mm (Newtons per millimeter) and evaluated alongside the peel pattern (per VDI 2019 classification): 

• Good bonding starts at 2.5 N/mm, but most of our materials—excluding very soft grades like 20–30 Shore A—exceed 3.5 N/mm. 
• A peel pattern rated B or higher (B to D) further confirms a strong mechanical connection between TPE and PA. Peel patterns are qualitatively assigned a rating from A to D, with D indicating the strongest bond and best adhesion.
• In short: >3.5 N/mm peel strength + a B or better peel pattern = strong, reliable bonding—exactly what manufacturers need for long-lasting performance in demanding applications.

In any two-component application, the quality of the bond between TPS and nylon is essential for ensuring the final product’s durability, functionality, and longevity. Through careful material development, controlled processing conditions, and standardized adhesion testing—like the VDI 2019 peel test—KRAIBURG TPE ensures that every compound meets the high-performance standards our customers rely on. Whether you’re designing automotive parts, consumer goods, or industrial tools, our TPE solutions are engineered for strong, reliable bonding—bringing innovation and confidence to every application.