HEMC / MHEC Hidroxietil-metil-cellulóz

HEMC / MHEC (CAS 9032-42-2) is primarily used as a functional additive in drymix construction materials. It improves water retention, workability, open time, anti-sag performance, mortar consistency, and application behavior in tile adhesive, wall putty, skim coat, cement plaster, gypsum plaster, masonry mortar, EIFS / ETICS mortar, waterproof mortar, repair mortar, and ready-mix dry mortar systems.

Yes. HEMC (Hydroxyethyl Methyl Cellulose) and MHEC (Methyl Hydroxyethyl Cellulose) are two names for the same product family. The difference is only in naming convention — HEMC emphasizes the hydroxyethyl group first, while MHEC emphasizes the methyl group first. Both refer to the same chemical substance (CAS 9032-42-2) and are widely used in the cellulose ether and construction materials industry.

The commonly referenced CAS number for HEMC / MHEC is 9032-42-2.

In tile adhesive, HEMC / MHEC improves water retention to support cement hydration and bond strength, extends open time to give installers more working time for tile positioning, provides anti-slip behavior to prevent tiles from sliding on vertical surfaces, and improves troweling feel and application consistency. High to extra-high viscosity grades are typically used at dosages of 0.2%–0.4% of the dry mix weight.

The typical reference dosage is approximately 0.1%–0.5% by weight of the dry mix, depending on the application. For tile adhesive: 0.2%–0.4%. For wall putty and skim coat: 0.2%–0.5%. For gypsum plaster and masonry mortar: 0.1%–0.3%. Final dosage must always be confirmed through laboratory testing and job-site performance evaluation.

In wall putty and skim coat, HEMC / MHEC improves water retention to prevent rapid drying, enhances scraping smoothness and surface finish quality, improves spreading behavior and workability, and helps maintain consistent product texture throughout the application session. Medium to high viscosity grades are typically used.

Both HEMC / MHEC and HPMC are used in tile adhesive and can deliver similar core performance. Neither is universally superior. HEMC / MHEC is particularly established in European and international drymix construction markets. HPMC is more widely used across a broader range of industries. The right choice depends on your specific formulation, raw material system, performance targets, and market requirements. Formulation testing is always recommended.

Yes. HEMC / MHEC can be used in gypsum plaster and related gypsum-based systems to improve water retention, workability, smooth spreading behavior, and application consistency. However, because gypsum systems are sensitive to set time, HEMC / MHEC grade and dosage must be carefully selected and tested to avoid excessive retardation of the gypsum setting reaction.

Tile adhesive typically uses high to extra-high viscosity HEMC / MHEC, generally in the range of 60,000–200,000 mPa·s (measured at 2% aqueous solution). The exact viscosity grade depends on the formulation type, tile size and weight, required open time, anti-slip performance target, and application conditions. Final grade selection should be confirmed through formulation testing.

Surface-treated HEMC / MHEC delays hydration when the powder contacts water, preventing premature lump formation during mixing and allowing the powder to disperse evenly before viscosity develops — important in drymix mortar systems where the powder is mixed with water on the job site. Non-surface-treated HEMC / MHEC dissolves more quickly and is used in systems where fast viscosity development is required.

The right HEMC / MHEC grade depends on your application, required viscosity level, formulation system (cement-based or gypsum-based), water retention target, open time requirement, anti-sag performance need, application method, and raw material system. Contact LANDERCOLL with your application details, and our team can recommend suitable grade directions and support your formulation evaluation.

Beyond the HEMC / MHEC grade and dosage, performance in drymix mortar is significantly affected by cement type and quality, filler system (sand, calcium carbonate, talc), gypsum quality, ambient temperature, water quality, redispersible polymer powder content, starch ether addition, aggregate particle size, and application method. These factors should all be considered when conducting formulation testing and grade selection.