FC-12.6-M
Laundry Sanitizer
Ingredients
| Ingredient | Function | % w/w |
|---|---|---|
| Benzalkonium chloride (BAC 50%, C₁₂–C₁₆) | Antimicrobial (quaternary ammonium) | 4.0–5.0 |
| Cetyltrimethylammonium chloride (CTAC, 25%) | Co-surfactant, softening | 2.0–3.0 |
| Dipropylene glycol | Solubilizer | 3.0–5.0 |
| PEG-40 hydrogenated castor oil | Fragrance solubilizer | 0.5–1.0 |
| Fragrance (dermatologically tested) | Freshness | 0.3–0.8 |
| Citric acid | pH adjustment | 0.5–1.0 |
| Deionized water | Diluent | qs to 100.0 |
| Final specifications: BAC = 2.0–2.5%; pH = 5.0–7.0 |
Formulation Notes
Laundry sanitizers are rinse-cycle additives delivering antimicrobial efficacy, particularly important in cold-water washes where detergent and bleach action may be insufficient.
Formulation Card FC-12.6-M: Laundry Sanitizer
Benzalkonium chloride (BAC) is a cationic surfactant with the general formula [CₙH₂ₙ₊₁N(CH₃)₃]⁺Cl⁻. Its mechanism involves adsorption to negatively charged microbial membrane phospholipids, disrupting membrane fluidity and causing cell lysis . BAC is effective against Gram-positive and Gram-negative bacteria and enveloped viruses. The rinse-cycle addition is deliberate: during the main wash, anionic surfactants in detergent form insoluble complexes with cationic BAC, inactivating both. In the final rinse, after detergent removal, BAC deposits onto fabric surfaces unimpeded. The diluted rinse liquor concentration of ~0.01–0.02% exceeds the MIC for common skin flora including S. aureus and E. coli. Commercial products at 2.0–2.5% BAC claim 99.9% kill against standard test organisms .
An alternative active is chloroxylenol (PCMX, 4-chloro-3,5-dimethylphenol, CAS 88-04-0), a halogenated phenol effective against bacteria and fungi . PCMX operates at 0.5–1.0% in liquid formulations and has higher chemical stability than BAC, though its characteristic phenolic odor and low water solubility (0.03 wt%) require co-solvent solubilization .