Dipropylene glycol

DPG is generally available in two main grades: Fragrance Grade (DPG LO+) and Industrial Grade. For high-end applications like perfumes, cosmetics, and personal care, you must specify Low Odor (LO+) grade to ensure it does not interfere with the scent profile. For industrial uses such as unsaturated polyester resins, plasticizers, or brake fluids, Industrial Grade is sufficient and more cost-effective. Always verify the purity level, which should be ≥99.5% for premium applications.

Buyers should demand a Certificate of Analysis (COA) for every batch. Key parameters include moisture content (typically <0.1%), color (APHA <10), and acidity. For exports to Europe, ensure the supplier is REACH compliant. If the DPG is intended for food-contact packaging or cosmetics, verify compliance with FDA (US) or EC 1223/2009 (EU) regulations. ISO 9001 certification of the manufacturer is a baseline requirement for quality consistency.

DPG is a co-product of propylene glycol production and exists as a mixture of three isomers. Its high boiling point (232°C) and low volatility make it an excellent coupling agent and solvent. It is highly valued for its ability to bridge oil-soluble and water-soluble components, which is why it is the industry standard for reed diffuser base oils and fragrance diluents.

DPG is hygroscopic, meaning it absorbs moisture from the air. It should be stored in tightly sealed stainless steel or coated carbon steel tanks or drums. The ideal shelf life is 12 to 24 months when stored in a cool, dry, well-ventilated area away from direct sunlight and oxidizing agents. For bulk liquid purchases, ensure the supplier uses dedicated ISO tanks to prevent cross-contamination.

The primary risks include quality degradation due to moisture and regulatory non-compliance. To mitigate these, use third-party inspection services (like SGS or Intertek) to perform pre-shipment sampling. Ensure the Safety Data Sheet (SDS) is provided in the language of the destination country and follows the GHS (Globally Harmonized System) format to avoid customs delays.

DPG prices are closely tied to Propylene Oxide (PO) feedstock costs. Negotiate based on volume-based pricing tiers; typically, purchasing in Full Container Loads (FCL) of 215kg drums or ISO Tanks can reduce unit costs by 10-15%. Request CIF (Cost, Insurance, and Freight) terms if you want the supplier to handle logistics, but ensure the insurance policy covers chemical leakage.

While DPG is generally classified as non-hazardous for transport (non-DG), it is still a chemical product. You must ensure the supplier provides a 'Certification for Safe Transport of Chemical Goods'. For shipping to regions like Southeast Asia or North America, flexitanks can be a cost-effective alternative to drums for large volumes, provided the material is compatible with the flexitank liner.

Always utilize Secured Payment services offered by Made-in-China.com to ensure funds are only released upon proof of shipment (Bill of Lading). Avoid direct wire transfers to private accounts. Verify the supplier's Audit Reports and check if they are a Diamond or Gold Member with a long history of successful exports to your specific region.