Anhydrous Borax

Catalog NumberACM1330434-3

CAS Number1330-43-4

CategoryBoron Flame Retardant

Description	Anhydrous borax is a hard, glassy, granular material used in the production of glass, fiberglass, cleaning products, enamels and coatings, and metallurgy. Anhydrous Borax is a stable, white/clear granule that should be kept from moisture and humidity to maintain product integrity.
Synonyms	Sodium Tetraborate
Molecular Formula	Na2B4O7
Melting Point	1368°F
Purity	99.0% min
Appearance	Granular, Powder
Content	B2O3: 68.5 – 69.5% Na2O: 30.5 – 30.9% SO4: 150 ppm max Fe: 40 ppm max
Moisture Content	<1%
Notes	Custom powdering as well as custom packaging is available to meet your specifications.
Packaging	50 lb/25 kg

Case Study

Guanidine Phosphate/Borax Flame Retardant System for Wood Pulp Paper

Wang, Ning, et al. Carbohydrate Polymers, 2017, 178, 123-130.

The primary factor contributing to the reduced thermal stability of flame-retarded lignocellulosic materials is acid-catalytic degradation triggered by acid source flame retardants. This study developed a guanidine phosphate (GP)/borax (BX) flame retardant system, leveraging acid-base synergism, to address this issue in wood pulp paper (WPP).
Preparation of flame retardant WPP
To prepare the flame-retardant WPP, GP/BX solutions with varying mass ratios (total concentration: 7 wt%) were created by mixing the flame retardants into deionized water with mechanical stirring. These solutions were subsequently used to coat WPP samples, ensuring each sample contained a fixed flame retardant content of 15 wt% by adjusting the coating mass accordingly. The flame-retardant samples were then dried to a constant weight (9.41 ± 0.02 g) under vacuum at 100 ˚C for 24 hours.
Flame retardant properties and mechanisms
The flame-retardant treatment of WPP resulted in strong resistance to flame and brought about a limiting oxygen index (LOI) of 35.7%. The basic flame retardant Borax chemically interacted with acids from guanidine phosphate during initial heating to lower acidity levels. The treatment extended the thermal stability of lignocelluloses by slowing acid-catalytic degradation with the degradation peak temperature shifting from 286 °C to 314 °C. The addition of borax improved condensed phase formation to create a denser and stronger structure through reinforcement of borophosphate acid-base reaction products that established an enhanced protective barrier.

Expanded Graphite/Borax Synergistic Flame Retardant for Soft Polyurethane Foam

Chao, Chunyan, et al. Journal of Thermal Analysis and Calorimetry, 2018, 131, 71-79.

Researchers investigated the effectiveness of flame retardants such as borax, expanded graphite (EG), and their combination in protecting flexible polyurethane foam (FPUF) against fire.
Preparation of modified FPUF samples
Isocyanate, polyether polyols, and dimethyl silicone oil were thoroughly mixed in a 1-L beaker. The flame retardant was then added and stirred vigorously for 10 seconds. Borax and EG were used to treat the FPUF separately, with the formulations detailed in Table 1. The mixture was poured into an open mold (300 × 250 × 150 mm3) to create free-rise foam, which was subsequently placed in an oven at 70 °C for 24 hours to complete the polymerization process.
Key findings
Incorporating EG and borax at a 4:2 ratio enhanced the FPUF's flame retardancy, achieving a limiting oxygen index (LOI) of 27.2% and a UL 94 V-0 rating due to their effective synergistic interaction. The initial decomposition temperature (IDT), sharp maximum mass loss peak (Tm), and maximum rate of weight loss (Rmax) were reduced, while the initial temperature of decomposition (IPDT) and char yield saw marked increases. Additionally, the CONE test parameters for the FPUF/EG/Borax composites, such as heat release rate (RHR), total heat release (THR), CO2 and CO emissions, and smoke production rate (SPR), were notably decreased, indicating a synergistic effect of EG and borax in enhancing flame retardancy while minimizing CO and CO2 release.

Effect of Boric Acid and Borax Addition on Urea-Formaldehyde Sawdust Composites

Nagieb, Zenat A., et al. International Journal of Carbohydrate Chemistry, 2011, 1, 146763.

Researchers investigated how adding flame retardants like boric acid and borax affects both the fire resistance and mechanical characteristics of urea-formaldehyde boards created from sawdust fibers. They prepared experimental panels by combining three flame retardant concentrations of 0.5%, 1%, and 5% with 10% urea-formaldehyde resin based on the weight of the bone-dry fibers.
Key Findings
· The bending strength of finished boards decreased from 12.5 N/mm² to 5.049 N/mm² as flame retardant concentration increased from 0% to 5%.
· Surface water resistance of composites improved dramatically when small quantities of paraffin wax and boron compounds were introduced producing a hydrophobic effect.
· Effective flame protection for the composite material was achieved through the use of BA combined with BX. Five percent was confirmed as the best concentration for effective fireproofing with flame retardants. Sawdust can be transformed into affordable high-quality fire-resistant particleboards for use in ceiling tiles and other interior applications including partitions and false ceilings.

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