Non-Ionic Surfactant Selection By HLB And Cloud Point

HLB Is The First Filter

The hydrophilic-lipophilic balance of a non-ionic surfactant tells you what it can do. Below about 10 it favours water-in-oil emulsions. Between roughly 12 and 14 it works as a wetting agent and detergent. Above 15 it favours oil-in-water emulsions and acts as a solubiliser. The three families published here cover 7.6 to 18 continuously, so the HLB a formulation needs can almost always be met without leaving the range.

Cloud Point Is The Second Filter

A non-ionic surfactant becomes insoluble above its cloud point and drops out of solution, taking its performance with it. Cloud points are published wherever the source data gives them: NP-9 at 42-48C, NP-10 at 60-67C, OS-15 at 77-83C, NP-15 at 80-90C, A-40 at 90-95C, and A-20, NP-21, O-20 and O-25 at 100C or above. Check the highest temperature anywhere in the process, including local hot spots, not the average.

Three Families, Three Reasons

The NP series is alkyl phenyl based and runs HLB 8.9 to 18, with strong hard water and alkali resistance. The AEO series is fatty alcohol based across three sub-series and runs HLB 7.6 to 17.4, which is the route to take when a restricted substance list blocks alkyl phenol chemistry. FMEE is a fatty acid methyl ester ethoxylate: lower foaming, faster to defoam, faster to dissolve and stronger on grease, which is what industrial and hard surface cleaning needs.

Blending To Hit An Intermediate Value

Where no single grade sits at the HLB a formulation needs, two grades from the same family can be blended and the HLB calculated by weighted average. This is standard practice and it avoids reformulating around a value that happens to be stocked.

Reading The Published Grade Tables

Each grade row gives cloud point, hydroxyl value, pH at 25C and HLB, followed by the properties and applications the manufacturer lists. Blank cells mean the source does not publish that figure for that grade, and none has been estimated. Hydroxyl value is published mainly for the lower ethoxylate grades, cloud point mainly for the higher ones.

Practical Checks Before Committing

Run an emulsion stability ladder across two or three neighbouring HLB grades rather than trusting a calculated value. Check foam behaviour on the real equipment. Confirm hard water tolerance at your actual water hardness rather than at a standard. And confirm that the packing suits your dosing: these ship in 25 kg bags and 100, 200 and 215 kg drums and pails depending on grade, all as non-dangerous goods.