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Views: 222 Author: Rebecca Publish Time: 2026-02-07 Origin: Site
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● Classification by Viscosity Grade
● Degree of Substitution (DS, MS) and Grade Codes
● Particle Size and Dissolution Behavior
● Main Application Grades of HPMC
>> Cosmetic and Personal-Care Grade HPMC
>> Modified and Special-Function HPMC Grades
● Practical Guide: How to Choose the Right HPMC Grade
>> Step-by-Step Selection Framework
● Example: HPMC Grades in Tile Adhesive and Wall Putty
● Frequently Asked Questions (FAQ)
>> 1. What is the most important parameter when choosing an HPMC grade?
>> 2. Why do construction and pharmaceutical HPMC grades look similar but are not interchangeable?
>> 3. How does particle size influence HPMC performance in dry-mix mortars?
>> 4. Can higher viscosity always improve adhesive strength in tile adhesive?
>> 5. What is the difference between K, E, and F series pharmaceutical HPMC?
Hydroxypropyl methylcellulose (HPMC) is not a single material but a family of grades with different viscosity, substitution levels, particle sizes, and regulatory standards, each tailored for specific end uses such as construction, pharmaceuticals, food, and cosmetics. Choosing the right HPMC grade directly impacts product performance, production stability, and cost, especially in tile adhesive, wall putty, self-leveling compounds, tablets, and food formulations.
HPMC is a non-ionic cellulose ether derived from natural cellulose and chemically modified with methoxy and hydroxypropyl groups, which give it thickening, water-retention, film-forming, and binding properties. Different grades are mainly defined by viscosity, degree of substitution, particle size distribution, and application standards, for example construction, pharmaceutical, food, or cosmetic requirements.
Core grade families of HPMC include the following:
- Construction grade HPMC
- Pharmaceutical grade HPMC (often referred to as hypromellose)
- Food grade HPMC (commonly identified as E464)
- Cosmetic and personal-care grade HPMC
- Modified and special-function grades designed for specific technical purposes
In many construction applications, grades are indicated by viscosity codes, such as 40,000–100,000 mPa·s, while pharmaceutical suppliers often use codes like K4M, E5, or E15 to describe both viscosity and substitution type.
Viscosity is one of the most important parameters used to classify HPMC and is usually measured in mPa·s or cps in an aqueous solution at a specified concentration and temperature. Viscosity determines thickening power, water retention, sag resistance, and the flow behavior of your formulation in both construction and pharmaceutical applications.
Typical HPMC viscosity ranges and uses:
| Viscosity range (approx.) | Typical label examples | Typical applications | Key performance focus |
|---|---|---|---|
| 3–50 mPa·s / cps | E3, E5 type | Food stabilizers, low-viscosity solutions, light coatings | Easy pumping, low thickening |
| 100–4,000 mPa·s | E15, K15 type | Tablet film coating, binders, some sprays and solutions | Film formation, balanced flow |
| 3,000–15,000 cps | Mid industrial range | Surface coatings, adhesives, lower-thickness mortars | Moderate thickening, good leveling |
| 40,000–60,000 mPa·s | Standard construction | C1 tile adhesive, wall putty, general mortars | Workability, basic anti-slip |
| 60,000–80,000 mPa·s | High-performance | C2 tile adhesive, skim coat, demanding mortars | Water retention, open time, bond strength |
| 80,000–150,000+ mPa·s | High sag-resistance | Wall tile adhesive, heavy tiles, grouts | Strong anti-sag, long open time |
Lower viscosity grades provide better flow and faster dispersion but lower sag resistance and shorter open time. Higher viscosity grades deliver strong water retention, anti-slip performance, and thixotropy but require careful dosing to avoid over-thickening and processing difficulties.
The degree of substitution (DS) and molar substitution (MS) describe how many hydroxyl groups on the cellulose backbone are replaced by methoxy and hydroxypropyl groups. These substitution patterns control solubility, gel temperature, film-forming, and compatibility in different systems.
Typical substitution-related characteristics include the following points:
- Methoxy content around 28–30% usually provides lower gelation temperature, higher viscosity, and strong film formation.
- Hydroxypropyl content around 7–12% improves cold-water solubility, flexibility, and rheology in many liquid systems.
Several commonly used pharmaceutical substitution series, such as K, E, and F types, share a viscosity number, for example 4M for about 4,000 cps, but differ in substitution pattern. As a result, these series show different gelation temperatures and release behavior even at similar viscosities.
Particle size distribution has a direct influence on how quickly and uniformly HPMC disperses in water or dry mixes. This behavior affects lumping, hydration speed, and overall processing efficiency.
Fine particle grades tend to disperse and hydrate more quickly, which is beneficial for applications that demand rapid dissolution and smooth textures, such as cosmetic gels, pharmaceutical suspensions, and certain food systems. Coarser particle grades are often preferred in dry-mix construction products including cement mortar, plaster, and tile adhesive because they disperse more gradually during mixing and reduce the risk of premature lumping.
Selecting the proper particle size can reduce mixing time and minimize quality problems such as undissolved clumps or inconsistent viscosity in the final product.
Construction grade HPMC is optimized for cement- and gypsum-based systems, including tile adhesives, wall putty, renders, plaster, self-leveling compounds, and external insulation systems. Its main roles are to provide water retention, workability, open time, sag resistance, and stable consistency.
Key features of construction grade HPMC:
- Improves workability and trowelability of mortar and putty.
- Provides excellent water retention to support proper cement hydration and reduce surface cracking.
- Enhances adhesion to substrates and reduces sagging in vertical applications.
- Stabilizes air content and helps prevent segregation in mixed mortars.
In tile adhesives, viscosity selection is a crucial consideration:
- Standard C1 tile adhesive often uses grades around 40,000–60,000 mPa·s.
- High-performance C2 tile adhesive typically requires grades in the 60,000–80,000 mPa·s range.
- Wall tile adhesives and anti-sag formulations tend to use 80,000–100,000 mPa·s or higher, especially when applying large-format or heavy tiles.
For wall putty, many formulations choose high-viscosity construction grade HPMC to maximize water retention, anti-cracking behavior, and smooth application.
Pharmaceutical grade HPMC, often called hypromellose, is produced under pharmacopeial standards such as USP, EP, or JP, with tight control of purity, substitution levels, and residual components. It is widely used in solid oral dosage forms and liquid or semi-solid preparations.
Major uses include the following:
- Tablet binders and film coatings for immediate and modified release.
- Matrix former for controlled-release and sustained-release tablets.
- Capsule shells as a vegetarian alternative to gelatin.
- Thickener and stabilizer in eye drops, oral liquids, and topical preparations.
Pharmaceutical viscosity grades often range from about 3–100 mPa·s, with higher molecular-weight grades such as K4M or K15M used in extended-release matrices. Lower viscosity grades such as E5 or E15 are common in coatings and binder systems.
Food grade HPMC is approved as additive E464 and must meet strict safety and purity requirements, including limits on heavy metals, residual solvents, and microbiological contamination. It serves as a multifunctional thickener, stabilizer, and fat replacer in modern food processing.
Typical food applications are as follows:
- Bakery products, especially gluten-free bread and cakes, to improve volume and moisture retention.
- Dairy alternatives and plant-based beverages, where it provides body, stability, and pleasant mouthfeel.
- Coatings and batters, where it helps control oil uptake and improve crispness after frying or baking.
- Vegan meat analogs and capsule shells, where it contributes to texture and binding.
Substitution patterns and viscosity are tuned to achieve the required mouthfeel, clarity, and processing behavior in each food system.
Cosmetic and personal-care grade HPMC is designed for creams, lotions, shampoos, gels, and other topical products where clarity, sensory feel, and compatibility with surfactants and active ingredients are important.
Key roles in cosmetics and personal care include the following:
- Rheology modifier and thickener for stable emulsions and suspensions.
- Film former that improves feel and substantivity on skin and hair.
- Suspension aid for pigments, exfoliating particles, and insoluble actives.
Fine particle grades are often preferred for these applications to obtain uniform textures and avoid undissolved particles in clear gels or transparent formulations.
Beyond standard grades, many producers offer modified HPMC to solve specific technical challenges in demanding formulations. These special grades are engineered to enhance particular properties such as gel strength, water resistance, or compatibility.
Examples of modified and special-function grades include the following:
- Cross-linked HPMC, which offers enhanced gel strength and stability in high-performance controlled-release matrices or other systems requiring robust gel structures.
- Hydrophobic-modified HPMC, used in formulations that demand improved water resistance or wash-off resistance, for example in exterior coatings, paints, and specialty mortars.
- Compatibility-optimized grades, which are tailored to work with selected cement types, redispersible polymer powders, or specific surfactant systems.
Such grades are typically chosen during formulation optimization in close cooperation with a technical support team and backed by application testing.
1. Define the application and required standards
Start by clearly defining your target application, such as tile adhesive, wall putty, self-leveling, plaster, tablet coating, controlled-release matrix, or food and cosmetic products. Confirm any necessary regulatory or quality standards, for example pharmacopeial compliance, food additive requirements, or building standards.
2. Set target viscosity and rheology profile
Determine the viscosity range and flow behavior required by your process and end-use product. For tile adhesive, an overall window of around 40,000–100,000 mPa·s is often appropriate depending on whether you are formulating C1 or C2 grade products and whether they will be used on walls or floors. For extended-release tablets, medium to high viscosity pharmaceutical grades are usually preferred to build a robust matrix.
3. Select substitution pattern and gel temperature
Consider how gel temperature and solubility will interact with your process. Higher methoxy content provides a lower gelation temperature and stronger gel, which can be important in hot-water systems. Higher hydroxypropyl content improves cold-water solubility and flexibility, which is valuable in coatings and ophthalmic or oral liquid applications.
4. Adjust particle size and dispersion behavior
Choose the particle size according to your mixing equipment and process. Coarser powders are well suited to dry-mix mortars because they disperse efficiently and reduce lump formation during mixing. Fine grades are more suitable when fast wetting and very smooth textures are required, such as in cosmetic creams or food suspensions.
5. Verify regulatory grade and documentation
Confirm that the selected material is clearly designated as construction, pharmaceutical, food, or cosmetic grade. Check relevant certificates and documentation, such as USP or EP compliance for pharma, food-grade declarations for E464, or quality and safety certificates for construction and personal care.
6. Optimize dosage through lab and field testing
Conduct laboratory testing and, where relevant, field trials to fine-tune the dosage and grade choice. In practice, lower viscosity grades may need slightly higher dosage to reach a similar performance level, while higher viscosity grades can often be used at lower dosage. Evaluation should include parameters such as open time, sag resistance, workability, strength development, or release profile depending on the application.
For construction users, selecting the right viscosity window is especially important for achieving consistent performance on-site. Standard floor tile adhesive typically relies on medium-viscosity grades around 40,000–60,000 mPa·s, providing a balance of workability and adequate open time. High-performance C2-grade adhesive, used for more demanding conditions or larger tiles, usually benefits from grades in the 60,000–80,000 mPa·s range.
Wall tile adhesives and anti-sag formulations commonly use grades between 80,000 and 100,000 mPa·s or higher to deliver strong sag resistance when applying heavy or large-format tiles to vertical surfaces. For interior wall putty, many producers choose high-viscosity HPMC to ensure excellent water retention, anti-cracking performance, and smooth, easy application.
In every case, final grade selection should consider local cement type, filler characteristics, climate, and application method, and should be confirmed through systematic testing under practical conditions.
If you are evaluating HPMC grades for tile adhesive, wall putty, self-leveling compounds, pharmaceutical tablets, food products, or cosmetic formulations, it is essential to partner with a manufacturer who can provide consistent quality, technical support, and customized solutions. As a professional producer of cellulose ethers, including HPMC, HEMC, and HEC, Shandong Shengda New Material Co., Ltd. can help you match the right grade, viscosity, and substitution profile to your specific formulation and process. Contact our technical team with your application details and performance targets to receive tailored recommendations, formulation guidance, and sampling support for your next project.
Contact us to get more information!
In most real-world formulations, viscosity is the single most important parameter because it controls thickening power, water retention, sag resistance, and flow behavior. Other factors, such as substitution level and particle size, are also important, but viscosity is usually the first indicator when screening suitable grades for a new application.
Construction and pharmaceutical grades may have similar viscosity values, but they differ in purity, substitution pattern, particle size, and regulatory compliance. Pharmaceutical and food grades are produced under much stricter standards for residuals and contaminants, so construction grades typically cannot replace them in tablets, capsules, or food products, even if labels show similar viscosities.
In dry-mix mortars, particle size affects dispersion and hydration behavior. Coarser particles disperse more gradually, allowing HPMC to distribute evenly before it fully hydrates, which reduces lumping and leads to more consistent viscosity throughout the mix. Very fine particles can hydrate too quickly in this environment and create lumps if dispersion is not carefully controlled.
Higher viscosity does not automatically guarantee higher adhesive strength. While increasing viscosity can improve water retention and sag resistance, excessively high viscosity may reduce workability, make mixing more difficult, and even negatively affect the bond if the adhesive becomes too stiff. The best approach is to identify an optimal viscosity window for the formula and job conditions rather than simply increasing viscosity.
K, E, and F series pharmaceutical HPMC share similar viscosity numbers at a given code but have different methoxy and hydroxypropyl substitution patterns. These differences lead to distinct gelation temperatures, solubility behavior, and controlled-release characteristics, which is why formulators often test several series to determine which one best matches the required release profile and processing conditions.
