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HEMC for Gypsum Plaster

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Brief Product Description

Hydroxyethyl Methyl Cellulose (HEMC) for gypsum plaster is a dual-substituted cellulose ether that balances water retention, workability improvement, and sag resistance in machine-applied and hand-applied gypsum plaster systems. It enables smooth troweling, reduces cracking, and extends the setting window of gypsum-based renders.

Product Overview

EASONZELL™ ME Series grades for gypsum plaster are specifically tailored for the demanding rheological requirements of interior and exterior gypsum renders. HEMC's unique substitution pattern — combining hydroxyethyl and methyl groups — delivers a more temperature-stable viscosity profile compared to HPMC, making it particularly well-suited for machine spray application where frictional heat can temporarily raise mortar temperature.

The product dissolves quickly in cold water, forming a homogeneous gel network that holds gypsum particles in suspension and prevents water from bleeding upward during application. Our ME Series grades are available in building material grade and coating grade variants, each optimized for the specific particle size, viscosity, and set-time requirements of their intended application.

Specification

ParameterTypical Value / RangeTest Method
AppearanceWhite to off-white powderVisual
Viscosity (2% aq., 20°C)10,000 – 60,000 mPa·sASTM D2364
Methoxy Content (DS)1.2 – 1.8Titration
Hydroxyethoxy Content (MS)0.1 – 0.3Titration
Moisture Content≤ 5.0%ISO 585
Gel Temperature65 – 85°CCloud point
pH (1% solution)6.0 – 8.0pH meter
Particle Size99% pass 80 meshSieve analysis
Recommended Dosage0.1 – 0.4% of dry mix weight—

Application

EASONZELL™ HEMC is the preferred cellulose ether additive for gypsum-based plaster systems:

  • Machine-sprayed gypsum plaster — stable viscosity under pump pressure and frictional heat; prevents nozzle blockage.
  • Hand-applied finish plaster — imparts a creamy, workable consistency ideal for trowel finishing.
  • Gypsum board joint compound — smooth spreadability and controlled drying without excessive shrinkage.
  • Thermal insulation board adhesive — compatible with EPS and mineral wool substrates in interior gypsum systems.

Usage notes: Add HEMC to the dry gypsum blend. Avoid over-dosing, which can excessively retard set. Test open time at actual job-site temperature. For machine application, verify pump compatibility with your equipment supplier.

Advantages

  • Temperature-stable viscosity — HEMC's viscosity is less sensitive to temperature changes vs. HPMC, ensuring consistent pump-ability in machine application.
  • Superior sag resistance — maintains applied layer on ceilings and vertical walls without slumping.
  • Controlled set retardation — allows sufficient working time without over-retarding gypsum set.
  • Reduced cracking — water retention and plasticizing effect minimize drying shrinkage cracks.
  • Smooth trowel finish — fine particle size ensures lump-free mixing and an ultra-smooth surface appearance.
  • Versatile grade range — coating grade and building material grade options to suit interior render and base coat applications.

Frequently Asked Questions

  • Q: What is the key difference between HEMC and HPMC in gypsum plaster?
  • A: The main difference is thermal stability of viscosity. HEMC maintains a more consistent viscosity as temperature rises, which is important in machine-applied gypsum where frictional heat can elevate mortar temperature by 5–10°C. HPMC's viscosity drops more sharply under the same conditions.
  • Q: How much HEMC should I use in a typical gypsum plaster formula?
  • A: For interior gypsum plaster, 0.15–0.3% by weight of the dry mix is typical. Higher levels are used for external renders or when substrate absorption is high. We recommend running trials to optimize dosage for your specific gypsum binder and filler system.
  • Q: Can HEMC be used with retarder additives in gypsum systems?
  • A: Yes. HEMC is compatible with common gypsum retarders such as sodium citrate or protein-based retarders. However, since HEMC itself slightly retards set, reduce the retarder dosage accordingly to achieve your target working time.
  • Q: Does HEMC affect the final whiteness or surface appearance of gypsum plaster?
  • A: At normal dosage levels (below 0.4%), HEMC does not noticeably affect whiteness. However, higher dosages may slightly reduce brightness, so we recommend choosing the minimum effective dosage confirmed through application trials.
  • Q: Is your HEMC suitable for exterior gypsum render systems?
  • A: Our building material grade HEMC is designed for robust performance in both interior and exterior applications. For exterior use, it is often combined with redispersible polymer powder (RDP) to improve flexibility and water resistance.
  • Q: What particle size is available for machine-applied gypsum?
  • A: We offer 80 mesh (177 µm) and finer grades for machine-applied systems, ensuring quick, uniform dissolution when mixed with water at the machine nozzle. Coarser grades may cause delayed dissolution and uneven rheology in automated application.

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About Us
Zhejiang Yisheng New Material Co., Ltd.
Zhejiang Yisheng New Material Co., Ltd. is a professional enterprise engaged in the design, development, manufacturing, application, and sales of cellulose ether, located in the Shangyu Economic and Technological Development Zone, part of the Hangzhou Bay National Industrial Park. With a core concept of safety, environmental protection, and sustainable development, the company boasts an annual production capacity of 15,000 tons of cellulose ether, offering a complete range of products including HEC (hydroxyethylcellulose), HEMC (hydroxyethyl methylcellulose), and HPMC (hydroxypropyl methylcellulose). Our products serve various sectors such as oil fields, coatings, dry powder mortar, cosmetics, personal care products, medicine, and many others. Yisheng has a global presence, providing stable cellulose ethers and services to customers worldwide.
As a professional China HEMC for Gypsum Plaster Supplier and HEMC for Gypsum Plaster Company, The company adheres to the principles of safety and environmental protection as the foundation of its development. It implements and further consolidates safety and environmental protection measures, striving to create green and environmentally friendly production processes, safe and effective control systems, and orderly production management. This approach lays a solid foundation for the company's sustainable development. Yisheng boasts a scientific management mechanism, a comprehensive quality management system, stringent product testing methods, advanced technology, state-of-the-art equipment, and high-quality after-sales service.
Zhejiang Yisheng New Material Co., Ltd.

+86-18067879812
Zhejiang Yisheng New Material Co., Ltd.

sarah@ys-cellulose.com
Zhejiang Yisheng New Material Co., Ltd.