EDTA·Na₂ is widely used in personal care and household products due to its metal-chelating, stabilizing, and preservative-boosting properties. Below are common applications and guidelines for its use in daily chemicals.
1. Applications in Daily Chemicals
(1) Skincare & Cosmetics
Function: Prevents oxidation, stabilizes formulations, and enhances preservative efficacy.
Typical Usage:
- Creams & Lotions: 0.05–0.2%
- Prevents rancidity by chelating metal ions (Fe³⁺, Cu²⁺) that degrade oils.
- Shampoos & Conditioners: 0.1–0.5%
- Reduces mineral buildup (hard water deposits) and improves foam stability.
- Sunscreens: 0.05–0.1%
- Stabilizes UV filters (e.g., avobenzone) by preventing metal-catalyzed degradation.
(2) Liquid Soaps & Body Washes
Function: Enhances cleaning efficiency and prevents soap scum.
Usage:
- 0.1–0.3% in formulations.
- Works synergistically with surfactants (SLS, CAPB) to improve lather in hard water.
(3) Hair Dyes & Bleaching Products
Function: Stabilizes hydrogen peroxide (H₂O₂) and prevents metal-induced color distortion.
Usage:
- 0.1–0.5% in permanent dyes or bleaching creams.
(4) Oral Care (Toothpaste & Mouthwash)
Function: Prevents calcium deposits and stabilizes flavors.
Usage:
- 0.05–0.2% in toothpaste to reduce tartar buildup.
- Helps maintain freshness in mouthwashes.
(5) Household Cleaners & Detergents
Function: Softens water, improves surfactant performance, and prevents scale.
Usage:
- Laundry Detergents: 0.2–1% (enhances stain removal).
- Dishwashing Liquids: 0.1–0.5% (reduces water spotting).
2. How to Incorporate EDTA·Na₂ in Formulations
(1) Direct Addition (Cold Process)
- Step 1: Dissolve EDTA·Na₂ in warm water (40–50°C) at 1–5% concentration.
- Step 2: Add to the water phase of emulsions (before emulsification).
- Step 3: Mix thoroughly to ensure even distribution.
(2) Pre-Neutralization (For Acidic Systems)
- If the product pH is <5, pre-mix EDTA·Na₂ with a small amount of triethanolamine (TEA) or NaOH to prevent precipitation.
(3) Synergistic Use with Preservatives
- EDTA·Na₂ boosts the efficacy of preservatives like phenoxyethanol, parabens, or benzyl alcohol.
- Recommended Ratio:
- 0.1% EDTA·Na₂ + 0.5% phenoxyethanol (better than 1% phenoxyethanol alone).
3. Recommended Dosages
| Application | Typical Concentration | Purpose |
|---|---|---|
| Shampoos/Conditioners | 0.1–0.5% | Prevents mineral buildup |
| Face Creams/Lotions | 0.05–0.2% | Stabilizes oils & preservatives |
| Liquid Soaps | 0.1–0.3% | Improves lather in hard water |
| Hair Dyes | 0.1–0.5% | Stabilizes peroxide |
| Toothpaste | 0.05–0.2% | Reduces tartar |
| Laundry Detergents | 0.2–1% | Enhances stain removal |
4. Safety & Regulatory Considerations
- Cosmetic Regulations:
- Allowed in rinse-off products (no restrictions).
- Limited to 0.2% in leave-on products in some regions (EU).
- Environmental Impact:
- Not readily biodegradable; alternatives like Sodium Phytate or GLDA may be preferred for eco-friendly formulations.
5. Troubleshooting Common Issues
| Problem | Possible Cause | Solution |
|---|---|---|
| White precipitate | pH too low (<4) | Adjust pH to 5–8 with NaOH/TEA |
| Reduced effectiveness | Expired/contaminated EDTA | Test chelation capacity (calcium binding test) |
| Skin irritation | Overuse (>0.5%) | Reduce concentration or switch to milder chelators (e.g., citric acid) |
Conclusion
EDTA·Na₂ is a versatile ingredient in daily chemicals, improving stability, cleaning performance, and preservative efficacy.
- Best for: Hard water areas, oxidation-prone formulations, and preservative boosting.
- Alternatives: For greener options, consider Sodium Phytate, Gluconate, or GLDA.
By following these guidelines, you can effectively incorporate EDTA·Na₂ into cosmetics, cleaners, and personal care products.