Halogen-free ATH additives target thermoset composites

TOP: Result comparisons showcasing Optiload’s relative stability versus standard ATH. BOTTOM LEFT: Cimbar ATH’s thrmal decomposition endothermic reaction. BOTTOM RIGHT: Viscosity of standard 10 um versus Optiload LV 110 (cP). Source | Cimbar Resources Inc.

Cimbar Resources Inc. (Chatsworth, Ga., U.S.) globally offers non-halogen, fire-retardant and smoke-suppressant additives. Cimbar’s alumina trihydrate (ATH) products are versatile additives for composite applications, providing optimal flame retardancy, smoke suppression and mechanical reinforcement. Cimbar operates production and mining sites in the U.S., with additional operations in Mexico, China and Pakistan.

Cimbar says that its Polyfill, PolyJet and Optiload ATH product lines offer a wide range of particle size options for any industrial application. The company’s proprietary grinding, classifying and surface modification technology can be used in a wide range of polymers at processing temperatures below 220°C. Additional benefits include arc and track resistance in plastics exposed to electrical arcing, acid resistance and smoke suppression.

The ATH product lines are characterized by their flame-retardant and smoke-suppressant char barrier — three water molecules are released starting at 220°C, effectively forming this aluminum oxide char barrier. ATH also does not release harmful gas or toxic byproducts, and it can be recycled. It achieves an endothermic reaction, meaning it cools the surface, creates water vapor to form a barrier to the fuel and reduces smoke. Along these same lines, the additive provides thermal stability of polymers by dissipating heat during combustion, preventing or delaying combustion.

ATH additives act as a filler for polymers, improving mechanical properties like stiffness and abrasion. They provide UV resistance. Additional physical properties include:

An ultra-white to translucent color
High-purity with blush resistance
Fast gel time
Low viscosity, highly loaded 400 phr is possible with Optiload ATH

The ATH lineup’s particle size and distribution are designed for high gloss, matting (applications like powder coatings) and multiple viscosities for thermoset plastics (SMC, BMC and pultrusion). UL 94 V0 non-halogenated options are possible, and silane and surface treatments are available.