Zinc Borate (ZB-2335) CAS 12767-90-7

About Zinc Borate ZB-2335

Zinc borate ZB-2335 is the hydrated 2ZnO·3B₂O₃·3.5H₂O grade, a fine white crystalline powder rather than a liquid additive. The water in the structure is bound water of crystallization, not free moisture, and the powder stays non-hygroscopic and easy to handle in dry storage. Under strong heat the material gives up that water to cool the substrate and leaves a glassy borate residue that insulates the surface, encourages char and holds back smoke and afterglow. The bound water is retained to high processing temperatures, so the grade suits flexible compounds and engineering plastics processed hot, and the high whiteness keeps light and brightly coloured articles clean.

Applications

The powder is compounded into many polymer and non-polymer systems:

• Cable and flexible PVC compounds. Insulation, sheathing, conveyor belts and tarpaulins, where flame resistance is judged together with low smoke and controlled afterglow.
• Polyolefins and engineering plastics. Halogen-free PE, PP and EVA compounds and higher-temperature engineering resins that need a thermally stable, non-hygroscopic flame-retardant filler.
• Rubber and thermoset resins. Flame-retardant elastomer goods, epoxy and unsaturated polyester parts and adhesives, with dispersion checked for cure, strength and surface finish.
• Coatings, textiles and ceramics. Intumescent fire coatings, textile and carpet back coatings, ceramic glazes and frits, plus treated wood and paper products.

Specifications

ZB-2335 disperses as a fine filler in most compounding and coating processes and can be supplied untreated or with surface treatment to aid dispersion in a given polymer. The powder is stable under normal dry handling, virtually insoluble in water and compatible with the mixing, extrusion and calendering routes used for cable, profile and coating production. Lots are released with whiteness, particle size distribution, moisture and composition reported on the COA, and particle size and treatment status are matched to your compound before order confirmation.

Typical profile; industrial flame-retardant grade, and the batch COA governs.

Packaging and Storage

Zinc borate leaves as a dry powder in 25 kg laminated paper or woven bags, with bulk jumbo bags for high-volume compounding:

• Store in a dry, ventilated warehouse with the bag sealed and protected from moisture and tears.
• Non-hygroscopic by nature, but resealing opened bags keeps the powder free flowing and avoids contamination.
• COA, TDS and SDS accompany each shipment, with palletizing and export marking arranged for bag and bulk-bag orders.

Frequently Asked Questions

Q: Is ZB-2335 the hydrated or anhydrous grade?

A: ZB-2335 is the hydrated 2ZnO·3B₂O₃·3.5H₂O grade carrying bound water of crystallization, not the anhydrous material.

Q: Does it reduce smoke, not just flame spread?

A: Yes, it lowers smoke density and afterglow while building a glassy char, a key benefit for cable and enclosed-space uses.

Q: Can particle size and surface treatment be matched to our process?

A: Yes. Give us the polymer and route, and we confirm particle size and untreated or surface-treated grade before quoting.