How to Dissolving HPMC Powder? | Step-by-Step Guide
CONTENTS
Understanding HPMC
Hydroxypropyl methylcellulose (HPMC), a multifunctional cellulose derivative synthesized through alkaline treatment of wood pulp/refined cotton followed by propylene oxide and methyl chloride etherification, serves as the backbone additive in modern formulation engineering.
Widely utilized across industries, including construction materials (cement mortar, tile adhesives, wall putty), home/personal care (shampoos, detergents, cosmetics), pharmaceuticals, paints, and coatings, HPMC enhances industrial product performance by improving workability, viscosity, water retention, and other critical properties.
However, achieving these benefits hinges on one critical factor: proper dissolution techniques.
Optimize HPMC Dissolution Performance by Choosing Surface Treated or Non-Surface Treated
Selecting the correct dissolution method begins with identifying whether your HPMC is surface-treated or non-surface-treated
Non-Surface-Treated HPMC (Non-Delayed Solubility)
Produced via standard etherification (methyl chloride and propylene oxide), this type retains hydrophilic hydroxyl (-OH) groups on its surface. When mixed in cold water, non-surface-treated HPMC tends to clump. In hot water, however, it disperses quickly. As the solution cools and is continuously stirred, the viscosity gradually increases,forming a clear, gel-like colloid.
The special properties make this HPMC model highly suitable for dry-mix applications such as putty, mortar, and tile adhesives.
Surface-Treated HPMC(delayed-solubility )
It undergoes an additional production procedure by adding cross-linking additives (including glyoxal) to form temporary acetal crosslinks. This structural change delays water molecule permeation until mechanical shear or time breaks the bonds.
Surface-treated HPMC is ideal for quick dissolution in cold water and prevents clumping, especially for applications like liquid adhesives, paints, coatings, and home/personal care products.
How HPMC Structure Affects Dissolution Rates
Due to the structural differences between these two HPMC types:
Non-surface-treated HPMC requires heat activation to disrupt intermolecular hydrogen bonds, exposing hydrophilic groups to rapid dissolution. Moisture then penetrates the polymer matrix, causing particle expansion and forming a colloidal network that increases material viscosity. A shear rate ≥300 rpm is necessary to avoid agglomeration.
Surface-treated HPMC relies on glyoxal crosslinks to hydrolyze in water, dissolving within 2–5 minutes and gradually developing viscosity. Industrial data shows surface-treated HPMC achieves 90% viscosity development within 5 minutes at 25°C, whereas non-surface-treated grades require 30+ minutes without heat.
Step-by-Step Dissolution Protocols
A. Non-Surface-Treated HPMC: Hot Water Dissolution Method
1.Direct Dissolving in Hot Water
Preparation: Prepare water heated to 70–85°C (optimal range for breaking HPMC’s intermolecular hydrogen bonds). Avoid boiling water (>100°C), as excessive heat may degrade polymer chains and reduce viscosity.
Mixing Procedure:Slowly sprinkle HPMC powder into the vortex created by a high-speed mixer (≥500 rpm). Ensure the powder is added incrementally (e.g., 1–2% of total weight per minute) to prevent surface clumping.
Observe the hydration stages:
0–3 minutes: Powder floats on the water surface due to hydrophobic surface properties.
3–10 minutes: Particles absorb water, swell, and form a gel layer. Viscosity begins to rise.
10–30 minutes: The Gel layer dissolves into a homogeneous colloidal solution.
Cooling & Stabilization: Maintain stirring while cooling to 40°C,it can accelerate hydration and stabilizes viscosity (±5% variation). For large batches, allow 1–2 hours for full viscosity development.
2.Quick Bonding Method (Suitable for Dry-Mix Applications)
Step 1: Pre-heat 1/3–2/3 of the total water volume to 60–70°C in a mixing container. Add HPMC powder gradually while mixing at 600–800 rpm,creates a highly dispersed pre-gel with minimal air entrapment.
Step 2: Introduce the remaining cold water (10–25°C) in a steady stream. The sudden temperature drop triggers rapid hydration, achieving 80–90% of target viscosity within 5–8 minutes. Ideal for tile adhesives or self-leveling compounds requiring fast setup.
3.Powder Blending Technique
Premixing Guidelines:
-Blend HPMC powder with a large quantity of dry substance(e.g., cement, sand)in a ribbon mixer or planetary blender for 5–10 minutes. Ensure HPMC constitutes 0.1–0.5% of the total dry weight for optimal performance.
–Key advantage: Dry blending minimizes dust generation and ensures even distribution, reducing the risk of remaining undissolved lumps.
Hydration During Mixing:
-When water is added to the dry blend, mechanical friction raises the slurry temperature to 45–55°C, activating HPMC dissolution.
-Monitor viscosity changes: Initial low viscosity allows easy pumping,and the viscosity peaks after 15–20 minutes, extending open time for applications like renders or plasters.
B.Surface-Treated HPMC: Cold Water Dissolution Method
1.High-shear mixing method
-Equipment Requirements
Use a rotor-stator mixer or colloid mill capable of generating shear rates >10,000 s⁻¹. For small batches, a handheld immersion blender (≥800 W) is acceptable.
-Dispersion Phase
Add surface-treated HPMC to 20–25°C water under high-speed stirring (≥800 rpm). Initially, the polymer remains undissolved but fully dispersed,and the solution has no viscosity. The hydrophobic coating delays hydration, allowing particles to disperse uniformly without agglomeration.
-Visual check
The solution appears milky with no visible granules after 3 minutes.
-Hydration Activation
After dispersion, reduce stirring speed to 300–400 rpm and continue mixing for 10–15 minutes. The delayed hydration ensures viscosity develops gradually, preventing premature gelation.
C. Foam-Control Strategies
In cases where bubbles form, you can either add a defoamer or allow the solution to stand for a while to eliminate them.
1.Defoamer Selection & Dosage
-Silicone Defoamers: Add 0.05–0.1% dimethylsiloxane-based defoamer during the initial mixing phase. Silicone types are effective but may leave residues; avoid in food-contact applications.
-Non-Silicone Alternatives: Use mineral oil/polyglycol blends (e.g., BASF Foamaster® series) for eco-friendly formulations. Dose at 0.1–0.3% depending on foam severity.
-Testing: After adding defoamer, measure foam height reduction over 5 minutes, the industrial grades need to arrive at 90% collapse.
2.Process Optimization
To minimize air entrainment, you can Reduce agitation to 400–600 rpm after defoamer addition.
Application-Specific Selection Guide for HPMC
| — Parameter | — Non-Surface-Treated HPMC | — Surface-Treated HPMC |
|---|---|---|
|
Optimal Applications |
Dry-mix mortars,Gypsum plasters,Tile adhesives,Wall putty,etc. |
Shampoos,Detergent,tec. |
|
Dissolution Time |
10-30 mins(with heat) |
2-5mins (cold water) |
|
Viscosity Range |
10,000-80,000 mPa-s |
5,000-75,000 mPa-s |
|
Key Benefit |
Prolonged workability(>2 hours) |
Rapid batch turnover |
HPMC Dissolution Problems and Solutions
Problem 1: Clumping in Non-Treated HPMC
-Root cause: Insufficient heat or agitation.
-Fix:Preheat water to 80°C or use powder blending.
Problem 2：Low Viscosity in Surface-Treated HPMC
–Root Cause: Premature dilution before crosslink hydrolysis
–Fix: Ensure 2–3 minutes of high-shear mixing post-dispersion
Problem 3：Foaming in Liquid Systems
-use a better mixer machine or optimize mixer geometry (e.g., axial flow impellers) and add defoamers.
Pro Tips for Better HPMC dissolve
- Quality Check: Use HPMC with >99% purity to avoid impurities affecting dissolution.
- Temperature Control: Ambient temps >25°C slow surface-treated HPMC dissolution by 15%.
Not Just Follow the Step
Mastering HPMC dissolution isn’t just about following steps, it’s about understanding your material’s chemistry and application needs. Whether you’re formulating a high-strength mortar or a silky shampoo, the right technique ensures optimal viscosity, stability, and cost-efficiency.
To learn more about HPMC dissolution solutions，Contact with Mikazone’s technical team for for customized formulations, sample testing, and process optimization.
Keep Explore
How to Make Perfect Wall Putty with HPMC
Master Wall Putty Perfection,Optimize Formulations with Cellulose Ether & Polymer Additives to Prevent Cracking, Boost Adhesion, and Achieve Flawless Surfaces.
9 Steps To Test The Quality Of Your Cellulose Ether
Before purchasing a large quantity of cellulose ethers, a complete and comprehensive product quality inspection should be carried out. This article will show you the most comprehensive quality inspection process in the industry.
Surface-treated HPMC and Non-surface-treated HPMC: Choosing the Best for Your Application
How to choose the appropriate type of HPMC based on your application, considering that there are two types: surface-treated and untreated HPMC? What are the differences between the two types of HPMC?
2024 Chinacoat is Over, But Mikazone Keeps Advancing!
Unlock 2024 CHINACOAT Insights: Discover Mikazone’s Breakthrough Additives for Coatings, Cosmetics, and Oil Drilling—Secure Free Samples & Future Collaboration Opportunities Now.