Understanding HDPE
High-density polyethylene (HDPE) is the standard material for IBC tote inner bottles. It's chosen for its excellent combination of chemical resistance, durability, and cost-effectiveness. HDPE is resistant to most acids, bases, and aqueous solutions. However, it does have limitations — particularly with organic solvents and strong oxidizers.
Safe for HDPE Storage (Excellent Compatibility)
The following categories are generally safe for long-term storage in HDPE IBC totes: Water (potable, distilled, deionized). Most dilute acids (hydrochloric, sulfuric, phosphoric, acetic up to 50%). Most dilute bases (sodium hydroxide up to 50%, potassium hydroxide). Alcohols (methanol, ethanol, isopropanol). Detergents and soaps. Salt solutions and brines. Most food products (juices, syrups, oils). Agricultural fertilizers (liquid nitrogen, phosphate solutions). Hydrogen peroxide up to 30%.
Use Caution (Limited Compatibility)
These substances may be stored in HDPE but may cause gradual degradation over months to years, or at elevated temperatures: Concentrated nitric acid (above 50%). Concentrated sulfuric acid (above 70%). Bleach and strong chlorine solutions (gradually weakens HDPE). Some essential oils (may permeate through HDPE). Biodiesel and some biofuels. Concentrated hydrogen peroxide (above 35%).
Not Recommended (Poor Compatibility)
Do NOT store the following in HDPE IBC totes: Aromatic solvents (toluene, xylene, benzene — dissolves HDPE). Halogenated solvents (chloroform, methylene chloride, trichloroethylene). Concentrated nitric acid above 70% (oxidative attack). Fluorine gas or liquid (attacks all polymers). Bromine liquid. Strong oxidizing acids at high concentrations. Ether and some ketones.
Temperature Effects
Chemical compatibility can change dramatically with temperature. Many substances that are safe at room temperature become problematic above 140°F. HDPE softens above about 180°F and distorts above 230°F. Never store hot liquids above 175°F in an IBC tote without verifying material compatibility at that temperature. Cold temperatures actually improve HDPE's chemical resistance but make it more brittle mechanically.
When in Doubt, Test
If your specific chemical isn't listed in standard compatibility charts, conduct a simple soak test. Cut a small piece of HDPE (from a damaged tote or sample) and immerse it in the chemical for 7 days at the temperature you plan to store it. Check for swelling, discoloration, softening, or cracking. If the sample shows any changes, HDPE is not suitable for that chemical. Oklahoma IBC can assist with compatibility verification for unusual applications.