From VDI 2019 to DIN ISO 813-2
Liability lives up to what the standard promises

Thermoplastic elastomers in multi-component injection molding

One of the most compelling, if not the decisive argument for the use of thermoplastic elastomers (TPE) lies—as the name suggests—in their thermoplastic processability in multi-component injection molding. This technology makes it possible to inject TPE directly onto technical thermoplastics such as polyamide, polycarbonate, or polypropylene. This allows the mechanical strength and dimensional stability of the hard thermoplastic to be optimally combined with the softness, elasticity, and pleasant feel of a TPE in a single component. This synergy has contributed significantly to the success story of TPE and has led to a continuous increase in global production volumes over the last four decades.

From the VDI guideline 2019 to the international standard

Parallel to this technological development, the test methods for evaluating the adhesion between TPE and substrate materials have also been continuously refined and standardized. For many years, VDI Guideline 2019 was considered the recognized industry standard. It describes the testing of the adhesive strength of TPE on hard thermoplastics in two-component injection molding or insert molding processes. The force per millimeter required to separate the adhesive bond between the two materials is measured. The test is performed in a tensile testing machine in which the hard component is fixed on a movable slide and the TPE is pulled upward at a 90° angle. The resulting pull-off force is expressed in newtons per millimeter (N/mm). In addition, a qualitative evaluation of the fracture pattern is carried out after the peel test using code letters from A to D, which allow conclusions to be drawn about the type of failure.

DIN ISO 813-2 as an internationally valid standard

Since August 2025, DIN ISO 813-2 has been an internationally valid standard that standardizes precisely this test procedure, thereby placing the previous VDI 2019 on an international footing. The title is: Elastomers or thermoplastic elastomers – Determination of adhesion to a substrate – Part 2: Adhesion of a soft thermoplastic elastomer layer (ISO 813-2:2024). The content of the test method remains unchanged – neither the procedure nor the evaluation or the level of values has been adjusted. Only the designation has been standardized internationally and the content has been converted to the format standardized for these standards in accordance with ISO and DIN specifications. We are proud that Dieter Pauler, laboratory manager at KRAIBURG TPE, was actively involved in the development of this standard and was thus able to contribute his many years of expertise to international standardization.

KRAIBURG TPE switches to DIN ISO 813-2

KRAIBURG TPE has decided to switch completely from VDI 2019 to the new DIN ISO 813-2 during the fourth quarter of 2025. In the course of this, all relevant technical documents, such as data sheets and factory test certificates, will be adapted accordingly and made available to customers in the future.

Do you have any questions about adhesion tests with thermoplastic elastomers? Feel free to write in the comments or contact us.