Flamtard H flame retardant synergist inhibits the development of flames and smoke, and is safe for human health and the environment. Flamtard H is a zinc hydroxystannate that has both a condensed phase and vapour phase action during the rapid degradation of polyvinyl chloride and polymer materials containing halogenated and antimony additives. In halogen-free flame retardant polymer materials it can act to increase the char consistency and strength.

Flamtard H is insoluble in water and releases 15w% of water starting at 220 °C. At higher temperatures (400 °C - 600 °C), zinc and tin ions can be volatilised or liberated from their structure to exert catalytic activity. Flamtard H is part of a family of n-type wide bandgap semiconductors with a high concentration of free electrons in the conduction band, thus leading to high optical transmissions in combination with electrical conductivity. 



Chemical name Zinc hydroxystannate Chemical formula ZnSnO3.3H2O or ZnSn(OH)6
Molecular weight 286.15 C.A.S. number 12027-96-2


William Blythe’s Flamtard H is ideal for use in applications such as:

Coating Additives

  • Smoke suppressant and flame retardant synergist for flame retardant paints.
  • Transparent conductive oxide used in the manufacture of films for solar cells, touch screens, and energy efficient glass.

Polymer Additives

  • Smoke suppressant and flame retardant synergist with co-flame retardants. For polymer processing at temperatures below 220°C.
  • Co-additive in phosphate flame retardant containing polymer formulations to optimise char formation.

Process Chemicals

  • Solid lubricant additive in friction materials.

Product forms

William Blythe’s Flamtard H is available as a powder in both standard and free-flowing grades.

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