Boric acid

CAS: 10043-35-3

Overview

Boric acid (CAS 10043-35-3 ), also known as boracic acid and approved as food preservative E284 , is an inorganic boron compound sourced for its buffering and biocidal functions.

It acts as a pH buffer, preservative, and fire-suppressing agent depending on the application and concentration. Procurement teams across multiple sectors source it as a cost-effective, multifunctional mineral input.

In glass fiber and fiberglass manufacturing, it lowers melt viscosity and improves tensile strength in the final reinforcement product. Textile and leather processors apply it as a flame retardant finish and mold inhibitor.

Wood treatment and building products manufacturers use it to protect timber against fungi, insects, and fire. This is often done in combination with other boron salts to ensure long-term structural integrity and safety.

In personal care and pharmaceutical manufacturing, it functions as a pH buffer and mild preservative in topical formulations and ophthalmic solutions. It is valued for its stability and compatibility with various ingredients.

Boric acid is supplied as a white crystalline powder or granules, with granular forms preferred for dust-sensitive handling. Standard commercial grades include technical, USP , BP , and Ph. Eur.

Food-grade material is available to E284 specification for permitted preservation uses. Bulk supply is typically offered in 25 kg bags or big bags, with purity levels commonly at 99.5% or higher for industrial use.

Physical Properties

Melting Point	171 °C (decomp)
Boiling Point	300 °C
Density	1.435 g/cm³ @ Temp: 15 °C
Appearance	Boric acid is a white, amorphous powder or colorless, crystalline solid.
Color	≤10(APHA)
Odor	Odorless
Form	working solution
Water Solubility	49.5 g/L (20 ºC)
Vapor Pressure	2.6 mm Hg ( 20 °C)
Refractive Index	n20/D 1.330-1.340
pH	3.6-4.4 (25℃, saturated solution in H2O)
Log P	-1.09 at 22℃

Safety & Handling

Danger GHS08 GHS07 Hazard Statements H303 May be harmful if swallowed H315 Causes skin irritation H319 Causes serious eye irritation H335 May cause respiratory irritation H360 May damage fertility or the unborn child H370 Causes damage to organs H372 Causes damage to organs through prolonged or repeated exposure H402 Harmful to aquatic life Precautionary Statements P203 Obtain, consult and follow expert instructions for use. P260 Do not breathe dust/fume/gas/mist/vapours/spray. P261 Avoid breathing dust/fume/gas/mist/vapours/spray. P264 Wash … thoroughly after handling. P270 Do not eat, drink or smoke when using this product. P271 Use only outdoors or in a well-ventilated area. P273 Avoid release to the environment. P280 Wear protective gloves/protective clothing/eye protection/face protection. P318 IF exposed or concerned, get medical advice. P319 Get medical advice/attention if you feel unwell. P321 Specific treatment (see … on this label). P405 Store locked up. P501 Dispose of contents/container in accordance with local regulations. P264+P265 Wash … thoroughly after handling. P301+P317 Get emergency medical help. P302+P352 IF ON SKIN: Wash with plenty of water. P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing. P308+P316 Get emergency medical help immediately. P332+P317 Get emergency medical help. P337+P317 If eye irritation persists: Get medical advice/attention. Get emergency medical help. P362+P364 Take off contaminated clothing and wash it before reuse. P403+P233 Store in a well-ventilated place. Keep container tightly closed. P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code	28100090
Storage Class	6.1C - Combustible acute toxic Cat.3 toxic compounds or compounds which causing chronic effects
WGK (Germany)	2

Other Names

Industries

Water Treatment Textile, Leather & Paper Building & Construction Agriculture & Feed Plastics & Polymers Printing & Packaging Personal Care & Cosmetics Pharmaceuticals & Healthcare