How to accurately control the amount of cellulose ether added to tile adhesive

In modern building decoration projects, the quality of tile adhesives directly affects the safety and durability of the finishing system. In this paper, from the material proportion, mixing process, performance control of three dimensions, systematic elaboration of EN 12004 standard tile adhesive preparation technology, focusing on the analysis of cellulose ether in the system of the core role of the mechanism.

Formulation Design Basis Framework

1. Component Composition System

2. Standard formulation baseline (wt%)

Core mechanism of action of cellulose ethers

1. Water retention regulation

Hydration guarantee: extends water retention time from 30min to over 90min (EN 1348 test)

Principle of action:

Molecular chains form a three-dimensional network structure (hydration layer thickness 0.1-0.3μm)

Reduces the rate of water evaporation (slows down by 60-70%)

Key parameters:

Viscosity grade: 100,000-200,000 mPa-s (2% aqueous solution)

Degree of substitution: optimal water retention when MS=1.8-2.0

2. Rheology Control

Thixotropic index increase: from 1.5 to 2.8-3.5 (Brookfield RST test)

Shear thinning properties:

Static viscosity: 8000-12000mPa-s (to ensure anti-sagging)

Dynamic viscosity: 2000-3000mPa-s (to ensure smoothness)

3. Increased bond strength

Interfacial transition zone optimization:

Reduction of cementite porosity (from 25% to 18%)

Increase in polymer-cement contact point density

Experimental data:

4. Anti-sag performance

Vertical Surface Construction Thickness: Maximum Thickness without Sagging Increased from 3mm to 8mm

Mechanism Analysis:

Hydrogen bonding to form a supporting skeleton

Plastic viscosity＞5000mPa-s (critical anti-sagging value)

Mixing process control points

1. Raw material pre-processing

Aggregate drying: moisture control <0.5% (105℃ drying to constant weight)

Fiber dispersion: pre-mixed into the aggregate to prevent agglomeration

2. Mixing equipment parameters

3. Charging sequence optimization

Dry mixing stage (3-5min):

Aggregate + cement → mixing 1min

Add cellulose ether → mix 2min

Wet mixing stage (1-2min):

Slowly inject latex powder + calcium formate premix

Control temperature <40℃ (to prevent HPMC gel)

4. Mixing quality control

Homogeneity test:

Sampling 5 points, cellulose ether content deviation <± 0.05%

Color difference ΔE＜1.5 (colorimetric method)

Fineness requirement:

Remainder of 80 mesh sieve <0.5%

Agglomeration diameter <0.3mm

Influence of key process parameters

1. Mixing time gradient test

Conclusion: optimal mixing time 8-10min

2. Temperature control window

Mixing temperature >50°C: HPMC gels prematurely (30% drop in viscosity)

Solution:

Circulating water cooling jacket (maintain 35-40℃)

Batch feeding to reduce friction temperature rise

3. moisture sensitivity

When ambient RH > 75%:

Extend dry mixing time by 20%

Add 0.05% hydrophobic agent (calcium stearate)

Performance Verification Criteria

1. Main technical indicators

2. Cellulose ether special testing

Water retention rate: >98% (filter paper method)

Dissolution time: <3min (20℃ aqueous solution)

Ash content: ＜5% (800℃ cauterization method)

Solutions to Common Problems

1. Constructability anomalies

Short open time:

Improvement of HPMC viscosity grade (100,000 → 150,000)

Add 0.05% retarder (sodium gluconate)

Sticky knife phenomenon:

Decrease HPMC adding amount 0.05-0.1%

Add 0.1% starch ether

2. Strength defects

Low early strength:

Calcium formate addition raised to 1%

Use of early strength cement (52.5R)

Poor long-term water resistance:

Change to water-repellent HPMC (DS＞1.5)

Increase the addition amount of latex powder to 2.5%.

Environmental protection and cost control

1. Greening improvements

Bio-based HPMC (plant source substitution >30%)

Recycled aggregate applications (crushed tile aggregate substitution ≤ 40%)

2. Cost Optimization Strategies

Reach a verdict

By accurately controlling the addition amount of cellulose ether and mixing process, it can make the tile adhesive have excellent construction performance and mechanical strength at the same time.It has been proved that when the HPMC content is controlled at 0.25-0.35%, the mixing time is 8-10min, and the temperature is <40℃, the product has the best comprehensive performance.Future development directions include the application of intelligent mixing system (real-time monitoring of viscosity change) and functional cellulose ether (self-healing/temperature-sensitive response).
This technical solution has been successfully applied in a number of subway station house projects. While the dosage of single-component adhesive is reduced by 15%, the rate of tile cavitation is reduced from an industry average of 3% to less than 0.8%.The actual production of raw material fluctuations need to establish a response mechanism, it is recommended that each batch of rapid bond strength test (20min initial inspection method).

It is gratifying that in this round of experiments, cellulose ether and latex powder are completely used with Melacoll™ HPMC MP70000 and Mikrant™ RDP powder and VAE provided by Mikem, and the experiments have proved to be very effective and fully meet the requirements of the test, and our products have stood up to the test in a variety of experiments as well as in practical applications, and we are looking forward to more feedbacks from our customers, so that we can make our product performance We are looking forward to more feedbacks from our customers to make our products' performance more superior!