In the world of specialized industrial additives, few compounds offer the unique combination of properties that 3.5 Zinc Borate Hydrate does. As a flame retardant and smoke suppressant, it has become a critical component in polymers, coatings, and rubbers. But what exactly is it, and why should manufacturers consider it over other alternatives? With decades of experience in materials science and supply, Shandong Taixing Advanced Material Co., Ltd. provides this comprehensive guide, delving into the specifics that make this material a superior choice for demanding applications.
Chemically represented as 2ZnO·3B₂O₃·3.5H₂O, 3.5 Zinc Borate Hydrate is a finely engineered, white crystalline powder. Its "3.5" denotes the moles of water of hydration, a key factor influencing its thermal stability and decomposition characteristics. Unlike many halogen-based flame retardants, it functions through endothermic dehydration and the formation of a protective char layer, simultaneously releasing water vapor to dilute flammable gases. This multi-mode action makes it an effective, environmentally friendlier solution.
To ensure optimal performance in your formulation, precise specifications are crucial. Below are the detailed parameters for our high-purity 3.5 Zinc Borate Hydrate.
Chemical Formula: 2ZnO·3B₂O₃·3.5H₂O
Appearance: Fine white powder
Zinc Oxide (ZnO) Content: 37.0% ± 1.0%
Boron Trioxide (B₂O₃) Content: 48.0% ± 1.0%
Loss on Ignition (LOI): 14.5% ± 1.0%
Particle Size (D50): Typically 2-5 microns (can be customized)
Specific Gravity: 2.8 g/cm³
Dehydration Temperature: Begins above 290°C (554°F)
Refractive Index: ~1.58
For a quick comparative overview, see the table below:
| Property | Specification / Value | Impact on Application |
|---|---|---|
| Primary Function | Flame Retardant, Smoke Suppressant | Enhances fire safety, reduces toxic smoke. |
| Thermal Stability | Stable up to 290°C | Suitable for high-temperature processing (e.g., engineering plastics). |
| Acidity/Alkalinity | Near Neutral (pH ~7) | Non-corrosive to processing equipment. |
| Water Solubility | Very Low (<0.28 g/100ml) | Provides good weathering resistance in final products. |
| Synergistic Partner | Excellent with ATH, Mg(OH)₂, & Phosphates | Allows for cost-effective, high-performance formulations. |
Choosing the right additive is a balance of performance, cost, and regulatory compliance. Here's where 3.5 Zinc Borate Hydrate excels:
Halogen-Free & Environmentally Preferable: It contains no bromine or chlorine, making it a key ingredient for green chemistry initiatives and products requiring compliance with RoHS, REACH, and other stringent regulations.
Multi-Functional Efficacy: Beyond flame retardation, it suppresses smoke, inhibits afterglow, and acts as a corrosion inhibitor and antifungal agent.
Synergy for Cost Efficiency: When combined with fillers like Aluminum Trihydroxide (ATH) or Magnesium Hydroxide, it dramatically lowers the total loading required to achieve a target flame retardancy rating (e.g., UL94 V-0), improving physical properties and reducing material costs.
Processing Versatility: Its high dehydration temperature allows it to be used in polymers processed at temperatures up to 270°C, such as nylons, PBT, and certain engineering thermoplastics, without causing blisters or voids.
Applications Across Industries
This versatility translates into real-world performance across a spectrum of materials:
Polymer Compounds: PVC (wire & cable, flooring), polyolefins, epoxy resins, rubber (conveyor belts, seals).
Coatings & Paints: Intumescent fire-resistant coatings for structural steel.
Adhesives & Sealants: Enhancing fire safety in construction and automotive applications.
Wood & Textile Treatments: As a component in fire-retardant impregnation solutions.
Q1: How does 3.5 Zinc Borate Hydrate compare to 3.0 or 4.0 Zinc Borate variants?
A1: The number (3.5, 3.0, 4.0) refers to the moles of water of hydration. The 3.5 hydrate offers an optimal balance between thermal stability and flame-retardant efficiency. The 3.0 hydrate has a slightly higher decomposition temperature but may release its water content less effectively during a fire. The 4.0 hydrate decomposes at a lower temperature, making it suitable for lower-processing-temperature polymers like EVA but less ideal for engineering plastics. The 3.5 variant is the most widely used due to its broad compatibility and effective performance profile.
Q2: What is the recommended loading level of 3.5 Zinc Borate Hydrate in a typical polymer formulation?
A2: There is no universal "one-size-fits-all" loading level, as it depends on the base polymer, other additives, and the required fire safety standard. As a general guideline, it is often used in the range of 5-15% by weight. In synergistic systems with ATH, loadings of 5-10% zinc borate with 30-50% ATH are common to achieve high flame retardancy. For specific formulations, technical consultation with a supplier like Shandong Taixing Advanced Material Co., Ltd. is recommended to optimize both performance and cost.
Q3: Does 3.5 Zinc Borate Hydrate affect the mechanical or aesthetic properties of the final product?
A3: When used at correct loadings, its impact is minimal and often positive compared to high loadings of inert fillers. Its fine particle size and near-neutral pH help maintain good polymer flow and mechanical strength. Being a white powder, it may lighten the color of the compound, which is easily managed with pigments. Its low water solubility ensures long-term stability and minimal blooming or efflorescence on the product surface, preserving aesthetic quality.
In a market where consistency and quality are non-negotiable, partnering with an experienced producer is paramount. Shandong Taixing Advanced Material Co., Ltd. has built its reputation on a foundation of precise manufacturing control, rigorous quality assurance, and deep technical expertise. Our 3.5 Zinc Borate Hydrate is produced under stringent protocols to ensure batch-to-batch consistency in particle size distribution, chemical purity, and dehydration properties. We understand that your production cannot afford variability.
Our commitment extends beyond supplying a product; we offer technical support to help you integrate our materials seamlessly into your processes, ensuring you unlock their full potential. Whether you are developing a new flame-retardant masterbatch or improving an existing formulation, our team is equipped to be your collaborative partner.
For specifications, samples, or to discuss how our 3.5 Zinc Borate Hydrate can enhance your product's safety and performance, contact Shandong Taixing Advanced Material Co., Ltd. today. Let us provide you with the material excellence and expert support that your next project deserves.
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