Resources    Overview Preparation of Solutions Product Literature Samples Online Support   This page provides a brief summary of the important points of preparing solutions of CELLOSIZE™ hydroxyethyl cellulose. Much more detailed information is presented in the brochure CELLOSIZE Hydroxyethyl Cellulose (795KB PDF). Click on the title here and go to page 12 of the pdf file. To prepare CELLOSIZE HEC solutions easily, good agitation and pH control are recommended. Dispersing of QP-Type Agitation of solutions at a pH of 7.0 or lower is recommended to make initial dispersions. After the CELLOSIZE HEC is well-dispersed and with agitation maintained, the hydration rate may be accelerated by adjusting the pH to alkaline ranges and /or by increasing the temperature. Below pH 7.0, the hydration rate of QP grades is decreased. Above pH 7.0, the hydration rate is increased. Dispersing of WP- Type To achieve adequate dispersions, the WP-types of CELLOSIZE HEC require more careful techniques than the QP-types. Solution takes place more readily if agglomeration is avoided. Sprinkle the WP-type of CELLOSIZE HEC into vigorously stirred water. Control the agitation to give maximum shear and minimum air entrainment. Continue until a clear, homogenous solution is obtained. Depending on the particular application, slurry addition may be used to control agglomeration and to accelerate the rate of solution. Pre-Wetting CELLOSIZE HEC can be slurried in a water-miscible liquid (alcohols, acetone, diacetone alcohol, glycols) before adding it to water. Dry-Blending CELLOSIZE HEC can be blended with other dry materials, either soluble or insoluble, before adding it to the formulation. Pigments, fillers, or dyes can thus be used to aid in the dispersion. Surfactant Addition The addition of about 0.01 percent surfactant to the water can aid in wetting and dispersing any WP-type of CELLOSIZE HEC. Effect of pH The effect of pH on the dissolving characteristics of a QP-type CELLOSIZE HEC is illustrated in Figure 4. Six Important Steps to Optimum Performance Agitate continuously while adding thickener. Do not stop the mixer until solution is clear and smooth. Quickly sift the thickener into the solution. Do not dump or shovel it in. Water properties influence dissolving time. Note that hydration time decreases as pH and temperature are increased. Do not add anything that will raise the pH of the water until the thickener particles have been wetted out. Two or three minutes mixing will usually accomplish this. Raising the pH thereafter markedly increases the rate of solution. Add an effective preservative at the earliest convenient point in the process. Store CELLOSIZE HEC in tightly closed containers to prevent absorption of moisture.