The Challenges of Modern Adhesives

Fire safety remains a critical concern across industries, with adhesives playing an essential but often overlooked role in preventing ignition, limiting flame spread and reducing heat release during fire events. For decades, antimony trioxide (ATO) in combination with halogenated flame retardants has been an industry standard additive in adhesive formulations. However, market shifts and regulatory pressures are driving manufacturers to seek more sustainable alternatives.

The adhesives market faces  challenges with antimony trioxide:

• A 6-10 × price increase for ATO in recent years
• Evolving regulatory requirements affecting traditional flame retardant chemistries
• Increasing demand for alternatives from customers seeking to diversify their material options

These challenges create an need for innovative solutions that maintain performance while addressing cost, regulatory and environmental considerations. The implications of these ATO challenges extend across diverse sectors where adhesives play critical roles:

Construction
Innovative building materials often rely on specialized adhesives for structural bonding, panel installation and flooring applications. Fire-resistant adhesives must perform reliably in these settings while meeting increasingly stringent building codes and sustainability certifications.
Automotive
Vehicle manufacturers face pressures of enhanced safety standards and lightweighting initiatives. Adhesives used throughout vehicle assembly require flame retardancy without the environmental concerns associated with traditional ATO solutions. Furthermore, the cost sensitivity to ATO price fluctuations creates challenges for maintaining economic viability.
Aerospace
Perhaps no industry demands higher performance from adhesive systems than aerospace, where flame retardancy is non-negotiable and material certification processes are exceptionally rigorous.

Addressing these market challenges, Clariant has developed phosphinate-based flame retardants that offer an alternative to antimony trioxide. These solutions represent the culmination of research and development focused on creating more sustainable options without compromising performance.

The phosphinate-based technologies deliver fire protection through different chemical mechanisms. When exposed to heat, these advanced formulations can create protective barriers that inhibit flame spread and reduce heat release rates but also help avoiding or delay ignition by quenching flammable gases.

The phosphinate advantage

Phosphinate-based flame retardants offer significant benefits across multiple dimensions:

• Halogen-free composition contributes to UN Sustainable Development Goals (SDGs), e.g. by promoting safer materials (SDG 3) and enabling circular economy through recycling (SDG 12). In addition, it aligns with the GlobalABC, reducing environmental impact and supporting circular economy principles
• Versatile compatibility with many different polymer systems enables broad application across adhesive types
• Comparable loading levels to ATO-based systems, simplifying reformulation processes

The transition from antimony-based to phosphinate-based flame retardants doesn't require sacrificing performance. Clariant's solutions have demonstrated the following results in key testing protocols:

• Flame spread reduction
• Heat release limitation
• Smoke development minimization
• Char formation enhancement

Applications across industries

The phosphinate-based flame retardants demonstrate versatility across adhesive applications:

Construction adhesives

• Floor installation systems
• Panel bonding formulations
• Structural adhesives for engineered wood products

Automotive assembly

• Interior component bonding
• Structural adhesives for mixed-material joining
• Lightweight composite bonding systems

Aerospace applications

• High-performance structural adhesives
• Interior panel installation
• Specialty bonding systems for critical components

As regulatory frameworks continue to evolve and sustainability becomes increasingly central to material selection, the transition away from antimony trioxide represents not just a necessity but an opportunity. Clariant's phosphinate-based flame retardants offer a forward-looking solution that addresses current challenges while positioning manufacturers for the future. 

(Source: Sebastian Moschel, Application Development Manager Passive Fire Protection at Clariant)