Introduction
Liquid Toilet Cleaner – Fresh Aqua is a high-efficiency toilet bowl cleaner designed to remove stains, limescale, and microbial buildup. It contains Hydrochloric Acid as the active descaler, supported by thickening and surfactant systems for clinging action and cleaning efficacy. The formula includes color-changing technology (“magic color”) and a refreshing fragrance.
This guide outlines how to formulate a market-ready, stable, and safe toilet cleaner that complies with regulations in the EU, ASEAN, and India.
Product Overview & Key Claims
- Removes stains, rust, and hard water scale
- Viscous formula for better adhesion to toilet surfaces
- Color-changing effect for cleaning assurance
- Fresh fragrance for sensory enhancement
- Acidic pH for disinfection and descaling
Ingredient Breakdown, Functional Roles, and Recommended Ranges
| INCI / Function Name | Functional Role | Recommended Range (% w/w) |
| Aqua | Solvent | 50.0 – 60.0 |
| Hydrochloric Acid (30–35%) | Descaling agent (acid) | 8.0 – 12.0 |
| Acid Thickener (e.g., Nonionic-Amphoteric Surfactant Blend like Laurylamine Dipropylenediamine) | Viscosity builder and surfactant | 2.0 – 4.0 |
| Surfactant Blend (optional: LABSA, CAPB) | Wetting & foaming (secondary cleaning) | 1.0 – 2.0 (combined) |
| Magic Color (e.g., pH indicator dye blend) | Visual indicator (pH-triggered color shift) | 0.05 – 0.1 |
| Fragrance (Fresh Aqua type) | Sensory appeal | 0.2 – 0.4 |
| Preservative (e.g., Benzalkonium Chloride) | Optional antimicrobial agent | 0.1 – 0.2 (if needed) |
Example Lab-Scale Formulation (100 g)
| Phase | Ingredient | % w/w | Amount (g) |
| A | Aqua (Purified Water) | 56.0 | 56.0 |
| A | Hydrochloric Acid (33%) | 10.0 | 10.0 |
| A | Acid Thickener (e.g., ARKOPAL AT or Rewopol SCB) | 3.0 | 3.0 |
| A | Cocamidopropyl Betaine (CAPB) | 1.0 | 1.0 |
| A | Linear Alkyl Benzene Sulphonic Acid (LABSA 90%) | 1.0 | 1.0 |
| B | Fragrance (Fresh Aqua) | 0.3 | 0.3 |
| B | Magic Color (e.g., Bromothymol Blue + Methyl Red) | 0.05 | 0.05 |
| Total | 100.0 | 100.0 |
Manufacturing Process
⚠️ Always wear acid-resistant PPE. Ensure proper ventilation and chemical fume extraction.
Equipment Needed:
- Polypropylene or HDPE mixing tank
- Overhead stirrer (acid-compatible)
- pH meter
- Acid dosing system (optional)
Process Steps:
- Phase A – Acid System
- In a clean plastic tank, add the required amount of purified water.
- Slowly and carefully add Hydrochloric Acid to water (NEVER the reverse). Stir continuously.
- Add acid thickener under stirring and allow viscosity to build.
- Add surfactants (CAPB, LABSA) and stir until homogeneous.
- Phase B – Additives
- Add fragrance and pre-dissolved color indicators.
- Stir gently to avoid foaming.
- pH Adjustment (if needed)
- Target pH: 1.0 – 2.0
- Check viscosity and clarity.
- Filtration and Packaging
- Filter through fine mesh (acid-compatible).
- Fill into acid-resistant HDPE bottles with angle-neck toilet cleaner caps.
Product Specifications
| Parameter | Specification |
| Appearance | Blue or green liquid (color shifts with use) |
| Odor | Fresh fragrance |
| pH (25°C) | 1.0 – 2.0 |
| Viscosity | 1,500 – 3,000 cP (Brookfield) |
| Specific Gravity | 1.05 – 1.10 |
| Stability | Stable for 24 months |
Stability Testing Plan
| Test Type | Conditions | Duration | Pass Criteria |
| Physical Stability | 5°C, 25°C, 40°C, 50°C | 3 months | No phase separation, color stable |
| Freeze-Thaw Test | 3 cycles (-5°C to 40°C) | 3 days/cycle | No precipitation or phase separation |
| pH Monitoring | Room temp | Monthly (3 mo) | Within 1.0–2.0 |
| Fragrance Stability | Room temp | 3 months | No off-odor |
| Viscosity Retention | 25°C and 40°C | Monthly | Within 15% variance |
| Packaging Compatibility | HDPE bottles | 3 months | No bottle corrosion or leakage |
Safety and Regulatory Notes
| Component | Hazards / Regulations |
| Hydrochloric Acid | Corrosive (GHS Class 8); requires danger labeling |
| Fragrance & Color | Should comply with IFRA and EU CLP labeling |
| Surfactants (LABSA, CAPB) | Must meet biodegradability per EU Detergents Regulation |
| pH | Must be disclosed if below 2.0 for consumer safety |
- Ensure clear labeling:
- Corrosive pictogram
- “Keep out of reach of children” warning
- First-aid instructions
- Provide proper SDS for transport and workplace safety.
Packaging Recommendations
- Use HDPE bottles with directional spouts for bowl application
- Include child-resistant closures (CRC)
- Use colorant-resistant labels with chemical resistance
- Label must include:
- Product Name & Use Instructions
- INCI/Composition Declaration
- pH Warning (if <2)
- Net Quantity
- Batch No., MFG/EXP Date
- Hazard Statements and Pictograms
Formulation Tips & Variants
| Objective | Recommendation |
| Premium Variant | Add Benzalkonium Chloride (0.2%) for antimicrobial effect |
| Visual Appeal | Use pH indicators like Bromocresol Green + Phenol Red |
| Mild Descaler Version | Replace HCl with Sulfamic Acid (~5%) |
| Eco-Friendly Version | Use Citric Acid and Nonionic Surfactants |
| Odor Masking | Add odor neutralizers like Zinc Ricinoleate |
Conclusion
Liquid Toilet Cleaner – Fresh Aqua is a powerful acidic cleaner that removes stains and limescale while offering visual appeal and sensory freshness. Proper formulation ensures high performance, compliance, and end-user safety. Manufacturers must implement robust safety practices, especially when handling and packaging corrosive agents like Hydrochloric Acid.
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