In the glass industry, safety is more than a feature, it’s a necessity. From architectural façades and balustrades to aerospace and train windows, laminated safety glazing units must look good – but also be able to absorb impact, retain shards, resist weathering, and maintain clarity for years. When it comes to creating the interlayer laminating films that help define how safety glazing units perform, one material chemistry stands out for its ability to meet complex demands: thermoplastic polyurethane (TPU).
TPU is a highly versatile elastomer created by reacting diisocyanates with polyols and chain extenders. This special chemistry is defined by its segmented block copolymer structure, which has soft segments that provide elasticity and flexibility, and hard segments that provide strength and durability. This dual-phase morphology gives TPU a combination of rubber-like flexibility and engineering-grade toughness; a balance that is particularly valuable in safety glazing applications.
In laminated glass systems, an interlayer film is bonded between two (or more) sheets of glass. In the event of impact, the interlayer must be able to help:
Not all polymers can meet these requirements simultaneously – but TPU can, equipping products such as our KRYSTALFLEX® film systems with advanced capabilities. Here’s why:
Impact resistance: TPU’s elastomeric nature allows it to stretch significantly without breaking. During impact energy is absorbed through elastic deformation. The material redistributes stress across a wider area while any cracked glass fragments remain adhered to the film. This combination can help improve post-breakage integrity, which is critical in architectural, automotive, and security glazing.
Adhesion: This is one of the most critical factors in laminated glass performance. TPU bonds strongly to glass, polycarbonate and acrylic surfaces, maintaining integrity even after fracture. Key advantages include reliable lamination under heat and pressure; strong interfacial bonding; reduced risk of delamination; and long-term structural retention. In structural and high-load glazing applications, this adhesion can contribute directly to residual strength after breakage.
Optical clarity: For architectural and automotive glazing, optical quality is non-negotiable. TPU films can be engineered to deliver high light transmission; low haze; minimal visual distortion; and long-term clarity. Unlike some alternative polymers, TPU can maintain visual performance even after prolonged environmental exposure. TPU also does not contain plasticizers, which can crazing of PC. Crazing is a type of surface damage where fine cracks or micro-fractures form in the material, which can look like a network of hairline fractures or a cloudy, spiderweb pattern.
Temperature resistance: One of TPU’s defining advantages is its wide operating temperature range, which can help ensure impact performance is consistent, all year round. At low temperatures, it has the ability to remain flexible rather than brittle. At high temperatures, it can retain its mechanical integrity. This makes it particularly suitable for automotive glazing; exterior architectural façades; and transport and specialty safety glass applications – which are all exposed to seasonal extremes. Prior to application, TPU also does not require special storage conditions like some other materials.
Tear strength: TPU film products such as our KRYSTALFLEX® systems exhibit high tensile strength; good tear resistance; and high elongation at break. In safety glazing, this means the interlayer can stretch while continuing to hold fractured glass in place, even under sustained loads such as wind pressure or blast forces.
Chemical / environmental resistance: In safety glazing, interlayer films must be able to withstand humidity; UV radiation; cleaning agents; and pollution exposure. TPU formulations can be optimized for hydrolysis resistance and UV stability, extending service life in demanding environments. This durability can help reduce long-term maintenance risk and enhances overall system reliability.
Design versatility: TPU’s thermoplastic nature allows it to be:
This flexibility allows manufacturers to tailor interlayer properties for specific end-use requirements, from sound reduction to high-security glazing.
For all of these reasons, TPU solutions such as our KRYSTALFLEX® TPU systems can provide an excellent option for safety glazing manufacturers seeking interlayer solutions that can help provide higher impact resistance, improved post-breakage integrity, and long-term reliability.
For more information please contact our team.
While all the information in this publication is to the best of our knowledge and belief accurate at the date of publication, NOTHING HEREIN IS TO BE CONSTRUCTED AS A WARRANTY, EXPRESS OR OTHERWISE. Huntsman warrants only that its products meet the agreed specifications. Typical properties, where stated, are to be considered as representative of current production and should not be treated as specifications. In all cases, it is the responsibility of the user to determine the applicability of such information and the suitability of any product for its own particular purpose. The sale of products referred to in this publication is subject to the general terms and conditions of sale of HuntsmanInternational LLC or of its affiliated companies.
KRYSTALFLEX® is a registered trademark of Huntsman International LLC or an affiliate thereof in one or more, but not all, countries. © 2026. Huntsman Corporation or an affiliate thereof. All rights reserved.
