What are the main properties and functions of methyl hydroxyethyl cellulose?

Methyl hydroxyethyl cellulose (MHEC) is a nonionic water-soluble cellulose ether widely used in construction, coatings, daily chemicals, oil drilling and other fields. It is a modified cellulose derivative made by introducing methyl (-CH₃) and hydroxyethyl (-CH₂CH₂OH) substituents into natural cellulose. MHEC has some advantages of hydroxypropyl methylcellulose (HPMC) and hydroxyethyl cellulose (HEC), and has excellent solubility, water retention, thickening and construction performance. It is an important additive commonly used in modern dry powder building materials and water-based systems.

Main properties

1.1. Appearance and solubility

MHEC is usually a white or off-white powder, tasteless and odorless, easy to disperse in cold water and form a transparent viscous solution. It is insoluble in hot water, but can be dispersed by pre-wetting with cold water and dissolved after the temperature drops. Its non-ionic properties make it stable to electrolytes and not easy to react with other ions.

1.2. Viscosity and rheological properties

MHEC can provide a variety of different viscosity grades, and the common unit is mPa·s (measured as a 2% solution at 20°C). Its viscosity is affected by factors such as molecular weight, degree of substitution (DS, MS), and shear rate. It has obvious pseudoplastic fluid characteristics (shear thinning behavior) and is suitable for spraying, brushing and construction.

1.3. Water retention

Its excellent water retention capacity is one of the important functions of MHEC in the building materials industry. It can significantly delay water evaporation, maintain the moisture of mortar, putty, adhesive and other materials during construction, and avoid cracks, powdering and other quality problems caused by too fast drying.

1.4. Film-forming and lubricity

MHEC can form a flexible and transparent film during the evaporation of water, providing good brushing and construction leveling properties for the coating. In dry mortar, it helps to improve the slipperiness and construction feel.

1.5. pH stability

MHEC solution is stable in the pH range of 4~11, is not easy to hydrolyze or degrade, and is suitable for a variety of systems. Even under alkaline conditions (such as cement mortar), it can exist stably for a long time.

Main functions and applications

2.1. Application functions in building materials

Dry mortar: MHEC is widely used in tile adhesive, plaster mortar, self-leveling mortar, thermal insulation mortar, masonry mortar, etc. Its main functions include:

Thickening and stability: improve mortar consistency, prevent stratification and water seepage.

Water retention: retain moisture, improve cement hydration efficiency, enhance bonding strength and crack resistance.

Constructability: enhance construction smoothness and open time, and reduce tool adhesion.

2.2. Putty powder and interior and exterior wall coatings:

Leveling and anti-sagging: enhance the fluidity and adhesion of materials after construction.

Storage stability: prevent pigments and fillers from settling and increase the storage period of coatings.

2.3. Application in the coating industry

MHEC is commonly used in water-based latex paints, adhesives, and gypsum coatings, and mainly plays the following roles:

Thickener and rheology modifier: adjust the construction viscosity and sagging properties of the coating.

Emulsion stabilizer: plays a stabilizing role in water-emulsion dispersion system to prevent separation.

Wetting and film formation: improve the uniformity of coating film and avoid brush marks and unevenness.

2.4. Role in daily chemical products

In personal care products such as shampoo, facial cleanser, and skin care products, MHEC has the following functions:

Thickening and stabilizing emulsified system;

Forming fine foam and improving skin feel;

Strong compatibility, good compatibility with a variety of surfactants, fragrances, and active ingredients.

2.5. Application in oil drilling

MHEC is used in drilling fluid and completion fluid as a filtrate reducer and rheology control agent:

Control viscosity and colloidal stability;

Prevent excessive water from entering the formation and protect the integrity of the well wall.

2.6. Other application areas

Papermaking industry: used as paper coating thickener and water repellent;

Ceramic molding: improve plasticity and improve molding stability;

Pesticide suspending agent: as a dispersant and adhesive, it helps pesticides adhere evenly to the leaf surface.

Methyl hydroxyethyl cellulose (MHEC) plays a key functional role in many industries due to its unique structure, which gives it excellent water solubility, thickening, water retention and construction rheological properties. Especially in modern building dry-mix mortar systems, MHEC not only improves the construction performance of the material and the quality of the finished product, but also improves the construction efficiency and environmental protection. With the development of green building materials and environmentally friendly coatings, the market demand for MHEC will continue to grow. When choosing MHEC products, companies should select the appropriate viscosity grade and alternative base content according to specific application requirements to obtain the best performance.