Propylene Glycol (PG) is a clear, colorless, odorless, viscous liquid widely used across resin, pharmaceutical, food, and industrial applications. For composite manufacturers, resin compounders, and chemical traders, understanding its core chemistry, grade options, and sourcing considerations helps ensure the right material is selected for each application. This guide summarizes the key technical facts buyers need before placing a bulk order.
Propylene Glycol (PG) Key Properties
Propylene Glycol is referenced under CAS No. 57-55-6, with a molecular formula of C₃H₈O₂ (see the PubChem compound record for verified reference data). It is completely miscible with water and most polar organic solvents, has low volatility, and exhibits excellent hygroscopic properties. Viscosity at 20°C is approximately 56 mPa·s, with water content typically kept at or below 0.2% in commercial-grade material. Its low toxicity profile compared to ethylene glycol makes it a preferred choice where that safety margin matters.
Propylene Glycol is produced commercially through the hydration of propylene oxide. It is available in both Industrial Grade and USP Grade, and buyers should confirm the required grade, water content specification, and packaging format with their supplier before finalizing a purchase order, since these parameters affect suitability for food, pharmaceutical, or industrial end uses.
Key Features of Propylene Glycol
- Available in Industrial Grade and USP Grade to match different application requirements
- Completely miscible with water and most polar organic solvents
- Low volatility and strong hygroscopic (moisture-retaining) properties
- Lower toxicity profile relative to ethylene glycol, supporting use in sensitive applications
- Low acute toxicity and not considered a skin or eye sensitizer at normal exposure levels
Main Applications of Propylene Glycol
In the composites and resin industry, Propylene Glycol is a primary raw material for unsaturated polyester resin (UPR) synthesis, where it reacts with dicarboxylic acids to form the polyester backbone. In pharmaceuticals, it is used as a solvent and carrier for oral, injectable, and topical formulations. Food-grade PG is an FDA-approved food additive (GRAS) used as a humectant and solvent for flavors and food colors, and in personal care it functions as a moisturizer, skin conditioner, and solvent in lotions and hair care products. Industrial applications include heat transfer fluids and de-icing solutions. Composite fabricators and resin compounders sourcing Diethylene Glycol (DEG) and other bulk chemical raw materials often evaluate Propylene Glycol alongside these related glycols for resin formulation work.
Safety and Handling Considerations
Propylene Glycol is classified as a low-hazard substance under most regulatory frameworks. It is not classified as flammable under standard conditions (flash point 99°C), has low acute toxicity, and is not considered a skin or eye sensitizer at normal exposure levels. It should be stored in a cool, dry, well-ventilated area in tightly sealed containers, away from strong oxidizing agents. Users should review the current Safety Data Sheet prior to handling and use appropriate personal protective equipment, such as chemical-resistant gloves and safety glasses, in industrial settings. Buyers should request current safety data sheet documentation from their supplier before bulk handling or storage planning.
Frequently Asked Questions About Propylene Glycol
What is Propylene Glycol used for?
It is used as a raw material for unsaturated polyester resin synthesis, as a solvent and carrier in pharmaceuticals, as an FDA-approved food additive, and in cosmetics, heat transfer fluids, and de-icing solutions.
What is the CAS number for this compound?
It is referenced under CAS No. 57-55-6, with molecular formula C3H8O2.
What grades of Propylene Glycol are available?
It is commonly supplied in Industrial Grade and USP Grade, with buyers confirming the required grade based on their end application.
How should this material be stored?
It should be stored in a cool, dry, well-ventilated area in tightly sealed containers, away from strong oxidizing agents, following current safety data sheet guidance.
Can Thousands Technology supply this material in bulk?
Yes, Thousands Technology provides supply chain resource support for resin manufacturers and industrial buyers sourcing this material, with grade, packaging, and logistics details confirmed per order.
For technical data sheets, grade options, or a bulk quotation for Propylene Glycol, contact our team through the inquiry form on this page to discuss your sourcing requirements.
