Çinko borat monohidrat

Zinc borate monohydrate (2ZnO·3B2O3·3.5H2O CAS NO.1332-07-6 / 138265-88-0) is a Flame Retardant for smoke and afterglow suppressant, and anti-arcing agent in polyvinyl chloride, nylon, epoxy, polyethylene, polypropylene, polyesters, thermoplastic elastomers and rubbers.

Zinc borate monohydrate, with the chemical formula 2ZnO·3B₂O₃·H₂O and a molecular weight of 389.68, is an important hydrate species in the zinc borate family. Its appearance is white crystalline powder, with a triple flame retardant mechanism of high thermal decomposition temperature (initial decomposition temperature>300 ℃), release of crystal water during combustion to absorb heat and cool down, and generation of borate oxygen barrier layer. At the same time, it has the characteristics of halogen-free, non-toxic, and strong weather resistance, which complies with national standards such as GB/T 23669-2022 and EU RoHS and REACH environmental certifications. It is an ideal choice to replace traditional halogen containing flame retardants. 
Shandong TaiXing Advanced Material Co., Ltd., was established in 1998, we are flame retardant china manufacturer and specialized in R&D and producing Environment-friendly halogen-free flame retardants including Zinc borate monohydrate and other flame retardant such as Ultrafine Aluminum hydroxide, Melamine Cyanurate (MCA), Aluminium Hypophosphite(AP), Ground Aluminum hydroxide, Magnesium Hydroxide(MDH), Hexaphenoxycyclophosphazene (HPCP), Magnesium hydroxide since 1998 .

Physical and Chemical Properties

physical property:

Appearance and particle size: White uniform powder, high purity (main content ≥ 99%), average particle size D50=2-5 μ m, can provide nanometer or micrometer level products according to demand, ensuring uniform dispersion in polymers without affecting material transparency and mechanical strength.

Density and solubility: specific gravity 2.8g/cm ³, bulk density 0.4-0.6g/cm ³; Slightly soluble in water (solubility 0.02g/100mL, 25 ℃), insoluble in organic solvents such as ethanol and acetone, excellent water resistance, suitable for material applications in humid environments.

chemical property:

Thermal stability: Stable at temperatures below 300 ℃, gradually releasing crystalline water (weight loss of about 4.6%) at 320 ℃, absorbing heat up to 800 kJ/kg, and reducing combustion surface temperature; The ZnO-B ₂ O3 glassy coating generated by decomposition can isolate oxygen and heat transfer, and suppress smoke generation.

Synergistic flame retardancy: When compounded with halogen-free flame retardants such as aluminum hydroxide and magnesium hydroxide, a synergistic system of "metal hydroxide+boron system" is formed, which increases the oxygen index (OI) of the material to over 30% and reduces the total amount of flame retardants added; When used in combination with bromine based flame retardants, it can reduce smoke emissions by over 40%.

application area

1. Plastic industry

Universal plastics: Adding 20-40% zinc borate monohydrate to PP, PE, and ABS, and modifying the surface with silane coupling agent, can achieve a UL94 V-0 flame retardant rating while maintaining an impact strength of ≥ 25kJ/m ². Typical applications include home appliance casings, car bumpers, electronic wires, etc.

Engineering plastics: used for high-temperature materials such as PA66 and PBT, utilizing their decomposition characteristics above 320 ℃ and matching the processing temperature of engineering plastics (280-320 ℃) to avoid premature decomposition during processing. Suitable for new energy vehicle battery module brackets, 5G communication equipment components, etc.

2. Rubber and elastomers

Tires and seals: Adding 10-15% zinc borate monohydrate to EPDM and NR (natural rubber) can reduce the heat release rate (HRR) during rubber combustion by 30%, while increasing the elongation at break to over 500%. It is suitable for automotive door and window seals, high-pressure hoses, etc.

Cable rubber insulation layer: compounded with magnesium hydroxide (ratio 1:3) for flame-retardant cables used in coal mines. It can pass the MT 818-2009 flame retardant test and meet the safety requirements of flammable and explosive environments underground.

3. Coatings and Building Materials

Expansion type fireproof coating: used as the core flame retardant filler (with an addition amount of 15-20%) for steel structure fireproof coating, it forms an "expansion carbon layer" with ammonium polyphosphate and pentaerythritol at high temperatures, making the coating have a fire resistance limit of more than 2 hours, in accordance with GB 14907-2018 standard.

PVC integrated wall panel: Adding 10-15% zinc borate monohydrate to wood plastic composite materials (WPC) can increase the combustion level of the board to GB 8624-2012 B1 level (flame retardant level), while improving weather resistance. It is suitable for indoor decoration, outdoor walkways and other scenarios.

4. Other fields

Lithium battery packaging material: Adding 5-8% zinc borate monohydrate to polypropylene (PP) separator can improve the thermal stability of the separator (thermal shrinkage rate ≤ 5%, 200 ℃/1h) and reduce the risk of battery thermal runaway.

Textile flame retardant finishing: endowing polyester fabrics with flame retardant properties through immersion rolling process (concentration 5-8%), with a damage length of ≤ 15cm during combustion, suitable for workwear uniforms, aviation seat fabrics, etc.

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