BIS Releases Draft Standard for Purified Isophthalic Acid – Stakeholder Comments Invited
The Bureau of Indian Standards (BIS), through the Organic Chemicals, Alcohols and Allied Products Sectional Committee (PCD 9), has released a wide circulation draft of a new Indian Standard titled Purified Isophthalic Acid (PIA) – Specification (PCD 9 (28154) WC). Stakeholders are invited to examine the draft and submit their comments through the prescribed template on the BIS portal by 8 March 2026.
The draft standard covers the specifications for PIA (CAS No. 121-91-5), which is widely used in the manufacture of PET resin, unsaturated polyester resins, and coating applications.
Key Highlights of the New Standard
- The draft standard specifies that purified isophthalic acid (PIA) should be a white crystalline, free-flowing powder that is free from extraneous impurities such as dust and dirt.
The material must also comply with the requirements given in the table below.
| Characteristics | Requirements |
| Moisture content, percent by weight,max | 0.10 |
| Ash content, ppm, Max | 15 |
| Acid value, mg KOH/g | 675 ± 2 |
| Total Metals (Co, Mn, Fe, Cr, Na, Ti, Mg, K, Ca, Ni),ppm, Max | 10 |
| Cobalt, ppm, Max | 1 |
| Manganese, ppm, Max | 1 |
| Iron, opm, Max | 1 |
| 3-Carboxybenzaldehyde, ppm, Max | 25 |
| m-Toluic acid, ppm, Max | 150 |
| Purity (by difference), percent by mass, Min | 99.88 |
- The b value*, representing colour-related impurities affecting polyester production, should be agreed upon between the supplier and purchaser.
Packaging and Marking Requirements
- The draft specifies that the material should be packaged in 25 kg, 500 kg, or 1,000 kg containers with proper labelling and sealed delivery. Bulk supplies require test certificates containing the required product details.
- Packages of purified isophthalic acid must be clearly labelled with the material name, the name of the manufacturer (and trademark if any), the manufacturing date, the net weight, the batch number, and any other statutory requirements.
- Products meeting the standard may be certified under the Bureau of Indian Standards Act, 2016, and may carry the BIS Standard Mark.
- This standard ensures consistent, high-quality PIA for industrial applications.
