How To Improve The Flame Retardancy of Adhesives?

How to Improve the Flame Retardancy of Adhesives?

Flame-retardant adhesives are designed to inhibit the spread of flames and reduce the hazardous effects of fires. These flame-retardant adhesives are versatile and suitable for bonding, masking, and damping applications on various surfaces such as polyester, polypropylene, ABS, stainless steel, polyethylene, polycarbonate, and aluminum.

I. Mode of Action When Using Flame-Retardant Materials
The flame retardancy of adhesives focuses on controlling the combustion process at the molecular level through the following methods: heat absorption, dilution of flammable components, interruption of flame chain reactions, creation of physical and insulating barriers, and enhancement of thermal stability and char formation.
Various mechanisms are employed to achieve flame retardancy in adhesives, including the use of intumescent systems, incorporation of additives, and polymer modification techniques. Intumescent systems work by swelling upon exposure to heat, forming a protective barrier over the adhesive that prevents oxygen from reaching the flame. Additive and polymer modification techniques can also contribute to achieving flame retardancy by altering the chemical composition of the adhesive and enhancing its fire resistance.

II. Formulation Strategies
The science behind adhesive flame retardancy involves manipulating the combustion process at the molecular level, as described above. This can be achieved through the following:

1. The incorporation of flame retardants is based on testing and regulations, not solely on chemistry.

• ATH (Aluminum Trihydrate) is an example of a filler-based flame retardant.

• Chlorendic anhydride is an example of an intermediate flame retardant.

• Beyond halogen-based options, phosphates are preferred.

• Al(OH)₃ has largely replaced all other types of flame retardants.

2. Intumescent Systems: Composed of ammonium polyphosphate, melamine, and pentaerythritol, these are typical for intumescent coatings.
Some resins with high thermal stability are advantageous in fire scenarios:

• Silicones: They can withstand high temperatures without significant degradation for a period. This is beneficial for delaying the ignition process. Compared to some organic materials, silicones produce less smoke when burned.

• Aromatic Polyimides: In addition to the benefits mentioned for silicones, aromatic polyimides tend to decompose and form a carbonaceous char layer upon high-temperature exposure. This char layer acts as a physical barrier, impeding further heat transfer and oxygen diffusion to the underlying material, thereby slowing the combustion process.

III. Conclusion
Want to add a "non-combustible" line of defense to your adhesive but worry about losing peel strength? Leave flame retardancy to us—Yinsu Flame Retardant Red Phosphorus Paste RP-TP46 and Halogen-Free Flame Retardant YS-F22B are specifically designed for adhesive systems: Adding just 5-8 phr achieves UL 94 V-0 rating, smoke density decreases by 40%, peel strength retention is ≥95%, with virtually no change in viscosity or curing time. Request samples now to make your adhesive both flame-retardant and strongly adhesive!