Polyalkylene Glycol Explained: Basic Facts And Uses

Polyalkylene glycols (PAGs) are unique among lubricants. They can have almost any solubility characteristics, and they are the only water-soluble class of lubricants. In addition, their cleanliness, especially their low tendency to form carbon deposits, is extremely important. Polyalkylene glycols were first used in water-based fire-resistant hydraulic fluids for military aircraft in World War 2, which were formulated from water, ethylene glycol, a polyalkylene glycol that acted as a thickener, and an additive package.

 

Similar to Synthetic esters used as airplane lubricants, PAGs were also "black technology" at that time. These super techs helped to win the war and changed the world. Nowadays, these synthetic base oils are still playing a very important role in the lubricant industry.

 

Chorus^® supplies high-performance Synthetic PAG base oils for various industrial applications, compressor oils, hydraulic systems, and gear oils.
Samples are available for your testing and evaluations.

 

 

 

What is Polyalkylene Glycol (PAG)?

Polyalkylene glycol is the common name for the homopolymers of ethylene oxide (EO), propylene oxide(PO), or butylene oxide(DO); or the copolymers of ethylene oxide, propylene oxide, and/or butylene oxide.

 

• The PAG polymerized by EO are generally called polyethylene glycols or polyethylene oxides.
• The PAG polymerized by PO are generally called polypropylene glycols or polypropylene oxides.
• The PAG polymerized by BO are generally called polybutylene oxides.

 

Where m, n = 2–500 (not simultaneously 0), and R1, R2, R3, R4 represent hydrogen or alkyl groups.

 

What are the types of PAGs?

 

By the epoxides (EO/PO/BO) arrange:

 

• Block PAG

Block polyether is a PAG in which ethylene oxide (EO) and propylene oxide (PO) form homopolymer long-chain segments and are arranged at intervals on the main chain. According to the block sequence, it can be divided into EPE type or PEP type.

 

• Random PAG

Random polyether is a PAG in which ethylene oxide (EO) and propylene oxide (PO) are randomly arranged on the molecular chain. The two monomers are randomly distributed on the main chain, and no monomer can form a single long-chain segment on the molecular chain.

 

By the water solubility, PAGs are divided into:

 

• Water Soluble PAGs

Copolymers of ethylene oxide (EO) and propylene oxide(PO), are the water-soluble type.

• Water Insoluble PAGs - PPG (polypropylene glycols)

Homopolymers of propylene oxide, water-insoluble PAG. Generally, they are not soluble in both water & oil.

• Oil Soluble PAGs

PAG(BO) - Polymers of butylene oxide - oil soluble + PAG (PO/ Higher expoxide) Polymers of propylene oxide and higher epoxides - greater oil solubility.

 

 

What are the main uses of Polyalkylene Glycol (PAGs)?

 

1. Water–glycol fire resistant hydraulic Fluids

Water glycol fire-resistant hydraulic fluid is a hydraulic fluid with fire-resistant properties, which is made of water, ethylene glycol, corrosion inhibitors, defoamers, and other special additives. It is widely used in metallurgy, machinery, mining, ships, and other industrial fields wherever fires cannot be tolerated.

Polyalkylene Glycol mainly provides viscosity in this kind of resistant hydraulic fluids. Chorus Lubricant Additives Company supplies the PAG for Fire Resistant Hydraulic Fluids, e.g. PAG 75W-18000, 75W-23000, 75W-50000, 75W-70000.

 

2. Compressor Lubricants

In some olefin gas compressors, when mineral oil is used as a lubricant, olefin gas can easily dilute the compressor oil, causing poor lubrication, pressure drop, and even seal wear and gas leakage, resulting in production shutdown.

Compressor oil based on PAG can solve the above problems. Since the dilution degree of hydrocarbon gas in PAG oil is very low, PAG-based lubricants are particularly suitable in methane, ethane, and ethylene compression.

 

3. Textile Lubricants

Due to water-soluble PAGs's non-staining and can be washed from the fabric with water, water-soluble polyalkylene glycols are widely used in the textile industry.

 

4. Metalworking Fluids

PAGs are widely used in various metalworking fluids, including cutting fluids( e.g., RPE1720, RPE1740 Excellent lubrication and low foaming performance, the lubrication performance is about 20%higher than that of ordinary PAGs.) Quenching fluids (PAG V10, HV45,75H380000, W55000, V05, HV20,75H90000, 75W18000).

 

5. Refrigeration Lubricants

PAG is widely used in refrigerators using HFC, hydrocarbon, and ammonia as refrigerants. 

e.g. Double-end-capped Poly Alkylene Glycol (PAG) is specially designed for automotive air-conditioning compressor oils with HFC refrigerants (R-134a), and HFO refrigerants(R-1234yf).

 

Chorus Lubricant Additives supplies a series of polyalkylene glycols ( PAGs). Get in touch for more about our PAGs portfolio.