The Difference Between HPMC and HEC in Construction Materials

In the modern construction industry, cellulose ethers have become indispensable functional additives that significantly

enhance the performance of building materials. Among them, Hydroxypropyl Methylcellulose (HPMC) and Hydroxyethyl

Cellulose (HEC) are two widely used non-ionic cellulose ethers. Although they share some similar characteristics, their

chemical structures, performance properties, and application focuses are distinctly different. For construction material

manufacturers, contractors, and formulators, understanding the difference between HPMC and HEC is key to optimizing

formulas, improving construction quality, and reducing costs. This article compares HPMC and HEC from the perspectives

of chemical structure, core properties, typical uses, and specific applications in construction materials, to provide a practi

cal reference for material selection.

1.Basic Overview of HPMC and HEC

1.1 What is HPMC?

HPMC (Hydroxypropyl Methylcellulose) is a non-ionic cellulose ether produced by modifying natural cellulose with methyl

and hydroxypropyl groups. It appears as a white or off-white powder, odorless, tasteless, non-toxic, and soluble in cold water

to form a transparent viscous solution. It has stable performance in most organic solvents except strong polar solvents. HPMC

is widely used in construction materials, pharmaceuticals, food, coatings, cosmetics, and other fields, and is the most commonly

used cellulose ether in dry mix mortar systems.

1.2 What is HEC?

HEC (Hydroxyethyl Cellulose) is also a non-ionic water-soluble cellulose ether, prepared by etherification of cellulose with

ethylene oxide. It has good water solubility, can be quickly dissolved in cold water to form a uniform solution, and has excellent

stability over a wide pH range (usually pH 2–12). HEC is widely used in water-based coatings, cosmetics, pharmaceuticals, oil

drilling, and construction materials, and is especially dominant in water-based systems.

1.3 Core Structural Difference

The fundamental difference between HPMC and HEC lies in their substituent groups:

HPMC contains both methyl and hydroxypropyl groups, giving it good water retention, thermal gelation, and film forming properties.

HEC only has hydroxyethyl substituents, resulting in better solubility, high temperature stability, and thickening efficiency.

This structural difference directly determines their performance divergence and application differentiation in construction materials.

2. Key Performance Differences Between HPMC and HEC

2.1 Water Retention

Water retention is one of the most important indicators for construction additives.

HPMC: Excellent water retention (usually 90–95%), forming a strong water binding network in cementitious systems, 

effectively

preventing rapid water loss in high temperatures or dry environments, ensuring full hydration of cement and gypsum.

HEC: Good water retention (85–90%), slightly lower than HPMC, but sufficient for most general construction scenarios.

2.2 Thermal Stability

HPMC: Shows thermal gelation; its aqueous solution will gel irreversibly when heated to about 60–90°C, which may

affect workability in high temperature construction.

HEC: No thermal gelation, maintaining stable viscosity even near boiling, making it more suitable for high temperature

construction or heated floor systems.

2.3 Solubility & Dispersion

HPMC: Soluble in cold water but prone to clumping if not dispersed properly; usually requires pre blending with 

dry powder to avoid agglomeration.

HEC: Better cold water solubility, faster dispersion, less prone to clumping, more convenient for on site mixing 

and water based systems.

2.4 Adhesion & Cohesion

HPMC: Strong adhesion enhancement, significantly improving bond strength between mortar and substrate, 

critical for tile adhesives and external insulation systems.

HEC: Moderate adhesion, better compatibility with superplasticizers and other additives, but lower overall 

bonding performance.

2.5 Rheology & Thickening

HPMC: Provides good thixotropy and antisagging, ideal for vertical plastering and large format tile installation.

HEC: Stronger thickening effect at low dosage, excellent leveling and color development, more suitable for water

based coatings and decorative mortars.

3. HPMC Uses and HPMC Applications

HPMC is the first choice for cement based and gypsum based dry mix construction materials, with the following core uses and applications:

3.1 Tile Adhesives

Extend open time and adjustability time

Improve anti-sagging and slip resistance

Enhance bond strength and durability

Suitable for ceramic tiles, stone, large format tiles, and external wall tiling

3.2 Cement Plasters & Renders

Improve workability and lubricity

Prevent cracking caused by rapid water loss

Improve adhesion to high absorption substrates

Reduce dust and improve on site working conditions

3.3 Wall Putty & Joint Compounds

Excellent water retention and anti cracking

Smooth scraping, easy sanding

Improve film density and surface finish

Widely used in interior and exterior putty formulas

3.4 Gypsum Based Materials

Gypsum plaster, joint filler, self-leveling gypsum

Control setting time and improve fluidity

Reduce shrinkage and cracking

Improve surface flatness and strength

3.5 Self-Leveling Floor Compounds

Anti sedimentation and anti segregation

Maintain stable fluidity and leveling

Improve surface finish and construction tolerance

3.6 External Thermal Insulation Composite Systems (ETICS/EIFS)

Improve adhesion to insulation boards

Enhance weather resistance and durability

Reduce water absorption and improve system stability

In summary, HPMC uses focus on dry mix mortars where water retention, adhesion, workability, and 

anti sagging are critical. It is the most widely used cellulose ether in the global construction industry.

4. HEC Uses and HEC Applications

Although HEC is also used in construction materials, its application scenarios are more focused on water 

based systems and decorative materials. The main HEC uses and applications are:

4.1 Water Based Paints & Coatings

As a thickener, stabilizer, and leveling agent

Improve anti sagging, anti splashing, and film uniformity

Enhance color development and surface gloss

Suitable for latex paints, elastic coatings, and decorative coatings

4.2 Gypsum Joint Compounds & Decorative Mortars

Improve fluidity and leveling

Control water retention and setting speed

Reduce shrinkage cracks

Improve surface smoothness and ease of sanding

4.3 Cement Repair Mortars & Grouts

Improve workability and pumping performance

Good compatibility with high efficiency water reducers

Suitable for repair projects and decorative grouting

4.4 Exterior Insulation Finishing Systems (Finishing Mortars)

Improve workability and weather resistance

Enhance coating uniformity and adhesion

Used in topcoat and finishing mortar formulas

4.5 Other Special Applications

Oil drilling fluids (rheology control and fluid loss control)

Cosmetics and personal care (thickening and stabilization)

Pharmaceutical suspensions and ophthalmic solutions

In short, HEC applications are more concentrated in water based systems requiring high leveling, high transparency,

and high temperature stability, and it is less used in high adhesion demand cementitious mortars.

5. How to Choose Between HPMC and HEC

When selecting between HPMC and HEC for construction materials, follow these practical principles:

Cement based dry mix mortars (tile adhesive, plaster, putty): prioritize HPMC for better overall performance.

Water based coatings and decorative mortars: prioritize HEC for better leveling and stability.

High temperature or hot environment construction: choose HEC to avoid thermal gelation.

Projects requiring high bond strength: choose HPMC to ensure long term durability.

Cost sensitivity: HPMC is generally more cost effective for mainstream dry mix mortars; HEC is more 

suitable for high end water based formulas.

Compound use: in some high end formulas, HPMC and HEC can be combined to balance water retention, 

leveling, and workability.

6. Conclusion

HPMC and HEC are both important non-ionic cellulose ethers widely used in construction materials, but 

they have clear positioning differences.HPMC excels in water retention, adhesion, and anti-sagging, making it the

mainstream additive for cement-based and gypsum-based dry-mix mortars.HEC has advantages in solubility, high-

temperature stability, leveling, and thickening, making it dominant in water-based coatings and decorative systems.

Understanding HPMC uses, HPMC applications, HEC uses, and HEC applications helps engineers and formulators select

the right additive, optimize product performance, improve construction efficiency, and enhance building quality. 

With the development of green building and high-performance construction materials, both HPMC and HEC will 

continue to play important roles, providing reliable technical support for the upgrading of the construction industry.

Name: Molly.Wang

E-Mail:molly.wang@jtdf-rdp.com

Mobile:+86 156 5045 0156（Whatsapp）