Relationship Between Viscosity and Temperature of Hydroxypropyl Methyl Cellulose (HPMC)

(1) Determination of viscosity: The dried product is prepared into an aqueous solution with a weight concentration of 2°C, and is measured by an NDJ-1 rotational viscometer;

(2) The appearance of the product is powdery, and the instant product is suffixed with “s”.

How to use hydroxypropyl methylcellulose

Add directly during production, this method is the simplest and the shortest time-consuming method, the specific steps are:

1. Add a certain amount of boiling water in a stirred vessel with high shear stress (hydroxyethyl cellulose products are soluble in cold water, so add cold water);

2. Turn on the stirring at low speed, and slowly sieve the product into the stirring container;

3. Continue stirring until all particles are soaked;

4. Add a sufficient amount of cold water and continue to stir until all products are completely dissolved (the transparency of the solution increases significantly);

5. Then add other ingredients in the formula.

Prepare mother liquor for use: This method is to make the product into a mother liquor with a higher concentration first, and then add it to the product. The advantage is that it has greater flexibility and can be directly added to the finished product. The steps are the same as the steps (1-3) in the direct addition method. After the product is fully wetted, let it stand for natural cooling to dissolve, and then fully stir before use. It should be noted that the antifungal agent must be added to the mother liquor as soon as possible.

Dry mixing: After fully dry mixing the powder product and powder materials (such as cement, gypsum powder, ceramic clay, etc.), add an appropriate amount of water, knead and stir until the product is completely dissolved.

Dissolution of cold water soluble products: cold water soluble products can be directly added to cold water for dissolution. After adding cold water, the product will sink quickly. After being wet for a certain period of time, start stirring until completely dissolved.

Precautions when preparing solutions

(1) Products without surface treatment (except hydroxyethyl cellulose) shall not be directly dissolved in cold water;

(2) It must be slowly sieved into the mixing container, do not directly add a large amount or the product that has formed into a block into the mixing container;

(3) The water temperature and the ph value of the water have an obvious relationship with the dissolution of the product, so special attention must be paid;

(4) Do not add some alkaline substances to the mixture before the product powder is soaked with water, and increase the ph value after it is soaked, which will help to dissolve;

(5) As far as possible, add antifungal agent in advance;

(6) When using high-viscosity products, the weight concentration of the mother liquor should not be higher than 2.5-3%, otherwise the mother liquor will be difficult to operate;

(7) Products that have been instant-dissolved shall not be used in food or pharmaceutical products.