liquid soap and liquid detergent formulations. When it is selected in the
right grade and dosage, STPP greatly improves cleaning efficiency, keeps
dirt from re-depositing on fabrics or hard surfaces, and stabilizes the
liquid system during storage.
Key points at a glance
- STPP enhances detergency and prevents soil redeposition in liquid soap.
- Typical dosage in household liquid detergents is 1.0–5.0% of the total formula.
- Choosing a reliable STPP supplier ensures stable quality, low impurity content and consistent performance.
1. Why STPP is Used in Liquid Soap
In liquid soap, surfactants such as LAS, AES or soap provide basic
foaming and cleaning. STPP acts as a multifunctional helper that
upgrades the whole system. It chelates hardness ions (Ca2+,
Mg2+), buffers pH, disperses soil and helps keep the bottle
clear and stable over time.
- Improves cleaning power by binding calcium and magnesium ions so surfactants work at full strength.
- Prevents redeposition of suspended dirt on fabric or hard surfaces.
- Buffers pH around mildly alkaline range for optimum detergency.
- Stabilizes formulations and reduces inorganic precipitation during storage.
For an overview of how STPP performs across different detergent
applications, see
Sodium Tripolyphosphate: Key Uses in Detergents and Food Additives
.
2. Recommended Dosage of STPP in Liquid Soap (Chart)
The ideal dosage of STPP depends on the detergent grade, target market and
water hardness. The following chart summarizes typical usage ranges
suggested by experienced STPP manufacturers.
*Percentage based on total finished formula weight. Exact dosage should be
optimized through lab trials according to water hardness, surfactant
system and local regulations.
Example Liquid Soap Formula with STPP
| Component | Function | Typical range (%) |
|---|---|---|
| LAS / AES / LABSA neutralized | Primary surfactants | 10.0–18.0 |
| Cocamidopropyl Betaine or similar | Foam booster, mildness | 2.0–5.0 |
| STPP (Sodium Tripolyphosphate) | Builder, chelating & anti-redeposition agent | 2.0–4.0 |
| Sodium carbonate / silicate | Alkalinity & corrosion inhibition | 1.0–3.0 |
| Solvents & hydrotropes | Stability, clarity | 2.0–5.0 |
| Preservative, fragrance, dye | Aesthetic & shelf life | q.s. |
| Water | Balance | to 100 |
For broader industrial applications such as metal cleaning or ceramic
additives, refer to the article
Application of Sodium Tripolyphosphate in Washing Industry
.
3. Choosing the Right STPP Grade and Supplier
Detergent-grade STPP parameters
- High active content and low water-insoluble matter.
- Proper bulk density for easy handling and dissolution.
- Controlled pH and phase composition (Phase I/Phase II).
- Low heavy metal impurities to meet local standards.
Where to source quality STPP
Goway Chemical provides industrial and detergent grade STPP with
stable quality and flexible packaging. For buyers and formulators,
these articles offer more guidance:
4. Practical Tips When Using STPP in Liquid Soap
- Add STPP under stirring and allow enough time for complete dissolution.
- Adjust pH after STPP addition; the optimum range is usually 8.0–10.0.
- Check storage stability at both low and high temperatures to avoid salting-out.
- Test performance in local tap water with typical hardness levels.
- Review regulations on phosphate discharge in your target market.
For cost and grade comparison, you can also read
Sodium Tripolyphosphate Price Analysis: Differences Between Industrial and Food Grades
.
FAQ: STPP in Liquid Soap
1. Is STPP safe to use in liquid soap?
Detergent-grade STPP is widely used in household and institutional
cleaning products. When used within recommended dosage and according
to local regulations, it is considered safe for normal cleaning
applications. As with any chemical, formulators should follow
applicable regulations, provide correct labeling and avoid direct
contact with eyes or undiluted product.
2. Can STPP be used together with other builders?
Yes. STPP is often combined with sodium carbonate, sodium silicate,
zeolite, or polymeric dispersants. In many formulations, a small
amount of STPP is used to boost performance while other builders help
control cost and phosphate discharge.
3. Does STPP affect the viscosity of liquid soap?
At practical use levels, STPP may slightly influence viscosity,
especially in systems with high electrolyte content. Viscosity should
be fine-tuned by adjusting salt level, solvent type and surfactant
ratio. Always run pilot batches to determine the optimum STPP dosage.
4. What happens if the dosage of STPP is too low or too high?
Too little STPP can lead to poor detergency in hard water and more
visible filming or spotting. Excessive STPP may cause clarity issues
or unnecessary cost. Starting from 2–3% and optimizing based on test
washing results is a practical approach recommended by most
manufacturers.
5. Where can I get technical support for STPP-based formulations?
Goway Chemical provides specification sheets, formulation suggestions
and application testing support for detergent customers. You can
explore our articles on
industrial STPP
and
OEM manufacturing services
, or contact our team for tailored recommendations.
