Tile adhesive, as a crucial bonding agent for interior and exterior walls, floors, bathrooms, and kitchens, has seen its formula widely regarded by enterprises as part of their core competitiveness. An effective tile adhesive formula can reduce costs, improve efficiency, and achieve optimal performance.
Based on years of production experience and practical expertise, Mikazone has summarized the optimal tile adhesive formula, particularly in the dosage of HPMC (Hydroxypropyl Methylcellulose) and RDP (Redispersible Polymer Powder), where it delivers exceptional effectiveness.
What is a C1 Tile Adhesive?
C1 Tile Adhesive is a cement-based, polymer-modified adhesive designed for fixing ceramic tiles, porcelain tiles, and natural stone on walls and floors. Classified under EN 12004 standards as C1 (indicating a “standard” strength adhesive suitable for fixing tiles in low-to-medium stress environments.), it offers reliable bonding for indoor and outdoor applications where moderate stress resistance is required.
The main difference between C1 and C2 tile adhesive lies in the application scenarios and performance requirements. C1 tile adhesive is suitable for ordinary tile laying, while C2 tile adhesive is suitable for places with high requirements for bonding strength and wear resistance, such as bathrooms, kitchens, and exterior walls.
What is a C1 Tile Adhesive Formulation?
While different C1 tile adhesives may have slightly adjusted formulations to optimize specific characteristics (such as open time, anti-slip performance, or workability), they generally follow the same fundamental composition. The base formula typically includes Cement, Quartz Sand, Hydroxypropyl Methyl Cellulose, Redispersible Polymer Powders, and other performance-enhancing additives to meet the EN 12004 standard requirement of ≥0.5 N/mm² bond strength.
C1 tile adhesive formulations include:
Main components of C1 tile adhesive formulations
2.1 Cement
Cement (typically Portland cement) in C1 tile adhesive provides hydraulic binding, strength, and durability. It reacts with water, forming a stable matrix that bonds tiles to substrates. Combined with polymers and aggregates, it ensures EN 12004-compliant adhesion, flexibility, and shrinkage resistance for interior/exterior applications.
2.2 Sand
Sand in C1 tile adhesive acts as a key aggregate, enhancing mechanical strength and dimensional stability. Optimal particle size distribution improves workability and adhesion while reducing shrinkage. Combined with cement and polymers, it ensures load-bearing capacity and durability.
2.3 Hydroxypropyl Methyl Cellulose (HPMC)
Hydroxypropyl Methyl Cellulose (HPMC) is a water-soluble cellulose ether widely used in construction materials like tile adhesives, playing multiple roles in enhancing performance and workability.
2.3.1 Benefits of HPMC in C1 Tile Adhesive
Improved Workability: HPMC enhances the open time and smooth application of C1 tile adhesive, ensuring better spreadability and reducing sagging on vertical surfaces for precise tile placement.
Water Retention: HPMC slows water evaporation, allowing proper cement hydration and strong bond formation, even in dry or high-temperature conditions, preventing premature drying and weak adhesion.
Enhanced Adhesion Strength: By improving cohesion and reducing shrinkage, HPMC boosts the adhesive’s bonding performance, ensuring durable tile installation with minimal risk of delamination or cracking over time.
Excellent Thickening: HPMC provides excellent viscosity control, preventing tile slippage after application and maintaining consistent mortar thickness, crucial for large-format or heavy tiles in C1 adhesives.
2.3.2 Typical Dosage & Selection Criteria of HPMC in C1 Tile Adhesive
Dosage: 0.2–0.5% of total dry weight (varies based on formulation and desired properties).
The optimal dosage depends on:
- Desired viscosity & workability.
- Substrate absorbency (higher dosages for porous surfaces).
- Climate conditions (hot/dry climates need more HPMC for water retention).
- Viscosity Grades:
- Low viscosity (e.g., 40,000–60,000 mPa·s): Balances workability and sag resistance.
- High viscosity (>100,000 mPa·s): For superior anti-sag, but may reduce workability.
- Particle Size: Fine powders (e.g., 80–100 mesh) dissolve faster, avoiding lumps.
2.3.3 Common Issues & Solutions about HPMC in C1 Tile Adhesive Formulations
Poor Water Retention:
HPMC fails to retain sufficient water, leading to premature drying and weak adhesion.
Solutions:
Use higher viscosity HPMC (e.g., 150,000–200,000 mPa·s)
Adjust cellulose ether dosage (0.2–0.5%)
Add a small amount of retarder (e.g.Mikaultra®MK301 starch ethers)
Slow Dissolution & Lumps Formation
HPMC clumps when mixed, causing uneven dispersion and reduced workability.
Solutions:
Pre-mix HPMC with other dry powders (e.g., cement, sand) before adding water
Use surface-treated HPMC (e.g., instant-dissolving grades)
Gradually sprinkle HPMC into water while stirring
2.4 Redispersible Polymer Powder(RDP)
As an essential additive in C1 tile adhesive, Redispersible Polymer Powder(RDP) is a free-flowing powder obtained by spray-drying polymer emulsions. When mixed with water, it re-emulsifies, forming a flexible polymer film that improves adhesion, flexibility, and workability.
2.4.1 Benefits of Redispersible Polymer Powder in C1 Tile Adhesives
- Crack Resistance: RDP improves the adhesive’s elasticity, reducing stress from thermal or structural movement and preventing cracks in tiles or grout lines for long-term durability.
- Superior Adhesion Strength: RDP forms a polymer film that boosts bonding to tiles and substrates, even on low-absorbency surfaces like porcelain, ensuring strong and reliable adhesion in C1 adhesives.
- Improved Water Resistance: RDP-modified adhesives resist moisture penetration, protecting the bond from weakening in wet areas like bathrooms and kitchens while maintaining breathability to prevent trapped moisture.
- Enhanced Workability: RDP enhances mortar consistency, reducing sagging and improving open time for easier tile adjustment, while ensuring uniform application and strong cohesion in vertical applications.
2.4.2 Formulation Design Guidelines for Redispersible Polymer Powder(RDP) in C1 Tile Adhesive
- Dosage Optimization
- Typical Range: 1.5–4% by weight of dry mix.
- Low Dosage (1.5–2.5%): Balances cost and performance for standard applications.
- High Dosage (3–4%): Required for high-flexibility adhesives or extreme conditions (e.g., exterior tiles, heated floors).
- Polymer Type Selection
- VAE (Vinyl Acetate-Ethylene): Most common for C1 adhesives, offering balanced adhesion, flexibility, and cost.
- Acrylic or Styrene-Acrylic: Higher water resistance and UV stability, suitable for exterior applications.
- Tg (Glass Transition Temperature) Considerations: Lower Tg polymers (e.g., -10°C to +10°C) enhance flexibility in cold climates.
- Synergy with Key Additives
- HPMC: Combines HPMC’s water retention with RDP’s adhesion to optimize open time and bond strength.
- Superplasticizers: RDP compensates for reduced cohesion caused by superplasticizers, maintaining anti-sag properties.
2.5 Hydroxypropyl Starch Ether
Hydroxypropyl starch ether is a modified starch derivative obtained by chemically treating natural starch with etherification agents (e.g., hydroxypropyl or carboxymethyl groups). It is used in C1 tile adhesives (EN 12004) as a rheology modifier and water retention agent.
2.5.1 Benefits of Starch Ether in C1 Tile Adhesives
- Improved Workability: Starch ether enhances the spreadability and plasticity of C1 tile adhesives, ensuring easy troweling and better coverage for efficient tile installation.
- Excellent Water Retention: It slows water evaporation, maintaining optimal moisture for cement hydration, which improves bond strength and prevents premature drying in hot or dry conditions.
- Anti-Sagging: Starch ether provides viscosity control, reducing tile slippage on vertical surfaces and ensuring consistent mortar thickness for secure placement of large or heavy tiles.
- Cost-Effective Performance: As a natural polymer, starch ether offers a balance of adhesion, workability, and water retention at a lower cost compared to synthetic alternatives in C1 adhesives
2.5.2 Typical Dosage in C1 Tile Adhesives
- Standard dosage: 0.05–0.3% (by weight of dry powder mix).
- Higher dosages (up to 0.5%) may be used for enhanced anti-slip properties.
Factors Influencing Dosage:
- Desired Workability – Higher amounts improve smooth application.
- Open Time Requirements – Adjusts water retention for longer working times.
- Anti-Slip Performance – Increased dosage reduces tile movement.
- Compatibility with Other Additives – Must balance with cellulose ethers (HPMC/MHEC).
2.6 Polycarboxylate Superplasticizer
Polycarboxylate Superplasticizer (PCE) is a high-performance water-reducing admixture used in C1 tile adhesives. It consists of a polycarboxylate ether (PCE) polymer backbone with long side chains that disperse cement particles through electrostatic repulsion and steric hindrance, significantly improving workability without extra water.
2.6.1 Benefits of Polycarboxylate Superplasticizer in C1 Tile Adhesives
- Superior Water Reduction: PCE significantly lowers water demand while enhancing flowability, ensuring easier application and improved spreadability of C1 tile adhesives without compromising strength.
- High Early Strength: PCE optimizes cement hydration, accelerating early strength development and delivering superior final bond strength for faster installation and long-term durability in demanding conditions.
- Excellent Sag Resistance: PCE provides precise rheology control, preventing tile slippage on vertical surfaces and ensuring consistent mortar thickness for secure bonding of large-format or heavy tiles.
- Enhanced Durability: PCE-modified adhesives exhibit reduced shrinkage and improved flexibility, minimizing micro-cracks and enhancing long-term performance under thermal or mechanical stress.
2.6.2 Dosage Optimization
Typical Range: 0.1–0.5% by dry mix weight.
Low Dosage (0.1–0.2%): For moderate water reduction and cost-sensitive formulations.
High Dosage (0.3–0.5%): For ultra-low water-cement ratios (e.g., high-strength adhesives or freeze-thaw-resistant systems).
Summary
While various C1 tile adhesive formulations may differ slightly to prioritize specific attributes such as adhesion strength, open time, or slip resistance, their performance hinges on high-quality functional additives.
As a pioneer in manufacturing advanced construction chemicals, MikaZone specializes in customizing Hydroxypropyl Methyl Cellulose (HPMC), Redispersible Polymer Powder (RDP) , Starch Ether, and Polycarboxylate Superplasticizer to empower C1 adhesives. Our solutions synergistically enhance workability, substrate compatibility, and crack-bridging capabilities while maintaining cost-efficiency and eco-conscious formulations. MEIKAI also offer customized formula according to your unique needs. Contact us and improve your tile adhesive now!