HPMC is not soluble in cold water?

HPMC solubility in various solvents

HPMC is short for hydroxypropyl methyl cellulose, cas no. 9004653. It is a water-soluble cellulose ether with the molecular formula C56H108O30.

Due to its special chemical properties, HPMC is soluble in cold water and certain organic solvents such as methanol, ethanol, isopropanol (IPA) and acetone. HPMC is also soluble in a mixture of water and organic solvents. This unique property is the reason why HPMC is very versatile and can be used in food, pharmaceuticals, daily chemicals products, construction, and is an indispensable additive in life.

Interestingly, HPMC is insoluble in hot water, but disperses evenly in hot water. Once the temperature is lowered, it dissolves quickly.

As a large producer of HPMC, we regularly do various tests on HPMC to ensure that the parameters of the product meet the requirements. In the tests, one type of HPMC will be condensed when added to cold water. It will not dissolve even with constant stirring, what is the reason for this?

Why does HPMC condense when dissolved in cold water?

Of course, HPMC is soluble in cold water. The reason why it condenses when dissolved in cold water is that when you put HPMC into cold water, the outer cellulose ether powder immediately becomes adhesive when it comes into contact with water and thickens to form a transparent gel. However, the cellulose ether inside the hydroxypropylmethylcellulose is wrapped inside by this gel before contacting with water, and cannot come into contact with water. This phenomenon is called coagulation.

So what we can do to avoid this? One way is to ease the HPMC powder into cold water so that it can fully dissolve, and another way is to use our surface-treated Grand Cellu™ HPMC powder.

Solubility of HPMC in cold water

There are two types of hydroxypropylmethylcellulose: surface-treated HPMC and non-surface-treated HPMC

Solubility of surface-treated Grand Cellu™ HPMC in cold water

When put surface-treated HPMC to water, the hydroxypropyl methyl cellulose disperses into the cold water. However, there is no stickiness, it just disperses. After stirring and waiting for about 2 minutes, the solution becomes thick and viscous.

This is because Grand Cellu™ HPMC has a cross-linking agent on its surface. This agent helps the hydroxypropyl methyl cellulose to disperse in cold water rather than dissolve at first. Surface treated HPMC is therefore more expensive than non-surface treated HPMC.

Solubility of unsurface treated HPMC in cold water

Hydroxypropylmethylcellulose products may condense when in contact with cold water. This is due to the fact that the outer layer of unsurfaced HPMC dissolves in cold water to form an HPMC gel. The HPMC powder is encapsulated in a transparent gel and the dissolution of the inner layer is slowed down considerably. This is generally avoided by dissolving in hot water.

Therefore, surface-treated HPMC is usually used in household products such as detergents and shampoos.

HPMC Dissolution and Viscosity Video

We have recorded our hydroxypropyl methylcellulose ether dissolution and viscosity up process in our lab, let’s watch it together.

  1. Weigh 8G HPMC
  2. Prepare 392g Boilde Water
  3. Mix them in a beaker and stir
  4. Put it into refrigerator for 30 minutes
  5. Take it out and the temperature is 23℃

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