IV (Intrinsic Viscosity) Value

Intrinsic Viscosity (IV) is the standard measure of PET resin molecular weight, expressed in **dL/g**. IV value directly determines preform processability, bottle wall thickness distribution, drop-impact resistance, and pressure tolerance for carbonated applications. Typical PET resin grades used in Indian beverage plants: - **0.78–0.80 dL/g**, water bottles, low-pressure preforms - **0.82–0.84 dL/g**, CSD bottles, juice bottles (higher pressure / hot-fill) - **0.85–0.88 dL/g**, large-format (1.5L, 2L) and premium pressurised SKUs IV variation between preform batches creates wall-thickness variation in blown bottles, even a 0.02 dL/g difference is noticeable to operators. Established preform suppliers maintain ±0.01 dL/g consistency; cheaper suppliers run wider tolerance. For water plants, IV variation rarely matters operationally. For CSD and hot-fill juice, IV consistency is a critical quality variable.