Exploring the factors behind growing demand for TPO-free light-curable adhesives.
As global regulations continue to evolve, manufacturers across industries are taking a closer look at the materials used in their products and processes. Increasingly, adhesive selection decisions are being evaluated not only for performance and manufacturability, but also for their potential impact on product qualification, regulatory compliance, and lifecycle management.
One material receiving increased attention is TPO (diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide), a photoinitiator commonly used in UV and LED light-curable adhesives. Regulatory developments and increased focus on substances classified as carcinogenic, mutagenic, or toxic to reproduction (CMRs) are prompting manufacturers to evaluate the materials used in both existing and future product designs.
While these considerations affect a range of industries, they can be particularly important for medical device manufacturers, where adhesive selections often remain in place for years and may require extensive validation and qualification efforts.
Why Is TPO Receiving Increased Attention?
TPO has long been valued for its ability to support fast, reliable curing in UV and LED light-curable systems. Its absorption characteristics made it particularly effective at wavelengths commonly associated with LED curing, helping manufacturers achieve rapid cure speeds while benefiting from the efficiency and reliability of LED-based curing systems.
As companies evaluate adhesive technologies for future products, many engineering and product development teams are asking:
- What impact could future regulatory changes have on existing products?
- Should alternative technologies be considered during new product development?
- How can organizations reduce the risk of future reformulation efforts?
Understanding the answers often requires balancing cure performance, substrate compatibility, manufacturing efficiency, qualification requirements, and application-specific performance criteria.
Key Questions
Why can switching away from TPO be challenging?
Photoinitiators are integral to the cure chemistry of light-curable materials, and changes to a formulation can affect cure speed, depth of cure, adhesion, color, shelf life, and material stability. As a result, evaluating alternatives often requires more than simply replacing one ingredient.
How has Dymax responded to growing interest in TPO-free materials?
Recognizing evolving industry needs, Dymax began developing TPO-free adhesives in 2018. Since then, the company has reformulated more than 90 products to be inherently TPO-free.
Development efforts focused on maintaining the performance characteristics medical device manufacturers depend on, including adhesion to challenging substrates, compatibility with medical plastics and metals, repeat sterilization, flexible assemblies, and low water absorption. Formulations supporting wearable assembly, catheter bonding, needle bonding, and select potting and encapsulation applications are available.
What’s new in the Dymax TPO-free product line?
Since introducing our first products in the TPO-free portfolio in early 2025, Dymax’s latest commercializations include:
- 1406-M-Z - A TPO-free LED-optimized medical adhesive for plastics and metals
- 1072-M-Z - A TPO-free non-fluorescing medical plastic assembly adhesive
- 1172-M-UR-Z - A TPO-free flexible plastics adhesive with Ultra-Red® fluorescing technology
Where can I learn more about TPO-free materials and industry trends?
Coming soon, Dymax will be releasing a full white paper that explores industry developments, adhesive selection considerations, and advances in TPO-free light-curable formulations.
Come back soon!
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