How To Use Hydroxyethyl Cellulose (HEC) in Latex Paint.

Our core product, HEC (hydroxyethyl cellulose), can provide you with higher quality products, and we can also customize different viscosities according to your needs. Shijiazhuang Qingquan Cellulose Co., Ltd. is a cellulose manufacturer from China.

1. Direct addition during pigment grinding: This method is the simplest and takes the least amount of time.

The detailed steps are as follows:

(1) Add an appropriate amount of purified water to the large tank of a high-shear mixer (generally, wetting agents and film-forming agents are added at this stage).

(2) Begin stirring continuously at a low speed and slowly add hydroxyethyl cellulose (HEC).

(3) Continue stirring until all particles are thoroughly wetted.

(4) Add antifungal agents, pH adjusters, etc.

(5) Continue stirring until all the hydroxyethyl cellulose (HEC) is completely dissolved (the viscosity of the solution will increase significantly) before adding other components of the formula, and grind until the paint is formed.

2. Preparation of Stock Solution: This method involves preparing a higher concentration stock solution first, and then adding it to the latex paint. The advantage of this method is its greater flexibility, as it can be directly added to the finished paint product, but proper storage is required.

The steps and methods are similar to steps (1)-(4) in Method 1, except that a high-shear mixer is not required; only a mixer with sufficient power to keep the hydroxyethyl cellulose uniformly dispersed in the solution is needed. Continue stirring until completely dissolved into a viscous solution. Note that the antifungal agent must be added to the stock solution as early as possible.

3. Preparation of a Slurry: Since organic solvents are poor solvents for hydroxyethyl cellulose (HEC), these organic solvents can be used to prepare a slurry. Ice water is also a poor solvent, so ice water is often used with organic liquids to prepare the slurry. The slurry of hydroxyethyl cellulose can be directly added to the paint. In the slurry state, the hydroxyethyl cellulose is fully swollen. When added to the paint, it dissolves immediately and acts as a thickener. After adding, continuous stirring is still required until the hydroxyethyl cellulose is completely dissolved and uniformly dispersed. Generally, the slurry is prepared by mixing six parts of organic solvent or ice water with one part of hydroxyethyl cellulose. After about 5-30 minutes, the hydroxyethyl cellulose will hydrolyze and swell significantly. In summer, the humidity of the water is generally too high, making it unsuitable for preparing the slurry.

4. Precautions for Preparing Hydroxyethyl Cellulose Stock Solution: Since hydroxyethyl cellulose is a treated granular material, it is easy to handle and dissolve in water if the following precautions are observed:

(1) Continuous stirring is required before and after adding the hydroxyethyl cellulose (HEC) until the solution is completely transparent and clear. (2) It must be slowly sieved into the mixing tank; do not add large quantities or lumps of hydroxyethyl cellulose directly into the mixing tank.

(3) Water temperature and pH value of the water have a significant impact on the dissolution of hydroxyethyl cellulose and require special attention. (4) Do not add alkaline substances to the mixture before the hydroxyethyl cellulose (HEC) powder is completely wetted by water. Increasing the pH after wetting will facilitate dissolution.

(5) Add the preservative as early as possible.

(6) When using high-viscosity hydroxyethyl cellulose, the concentration of the stock solution should not exceed 2.5-3% (by weight), otherwise the stock solution will be difficult to handle.

Factors affecting latex paint viscosity:

(1) The higher the content of air bubbles remaining in the paint, the higher the viscosity.

(2) Whether the amount of surfactant and water in the paint formulation is appropriate.

(3) The amount of residual catalysts and other oxides during the synthesis of the latex.

(4) The amount of other natural thickeners in the paint formulation and their ratio to the amount of hydroxyethyl cellulose.

(5) Whether the order of adding thickeners during the paint manufacturing process is appropriate.

(6) Overheating during dispersion due to excessive stirring.

(7) Microbial attack on the thickener.