As the most traditional and accepted detergent auxiliary, STPP (Sodium Tripolyphsphate) played an important role in the previous and current detergent industry, especially for the LAS system detergent, STPP contribute many assisting functions like:
Soften the water, binding the calcium ion and keep them inactive;
Good co-effecting with LAS and other anionic surfactant and enhance their ability;
Emulsifying the grease and fat;
Buffering the pH value of the washing liquid;
Improving the free-flowing property of the powder detergent, help to prevent the caking problem, and etc.
But due to the well-known phosphor pollution problems, many countries have started or are considering the related laws to limit or even stop the using of phosphates series detergents.
Zeolite was developed decades ago to replace STPP, with's its own advantages and disadvantages as below:
Advantage | Disadvantages |
| (1), Strong exchange ability to Ca2+ | (1), Low speed of exchanging of Ca2+ |
(2), Fast removing ability to Pb2+, Cd2+, Hg2 | (2), Low exchange ability for Mg2+ |
(3), Non-toxic, no irritation to eye and ski | (3), Not soluble in water, cause sediment in fabrics |
To replace STPP, meanwhile solve the Zeolite's disadvantages, we are now producing silicates series products: MSD and APSM.
| Index\ Item | STPP | ZEOLITE | APSM | MSD | |
| Synthetic | Natural | (also called PSM, PSMA) | Also called CSDS | ||
Full name | Sodium Tripolyphosphate | 4A Zeolite | Natural Zeolite | Activated Poly Sodium Metasilicate | Modified Sodium Disilicate |
Appearance | White fine powder | White powder | White granular powder | ||
| Whiteness | 90 min | 95 min | 80 min | 85 min | 85 min |
| Odor | No odor | No odor | No odor | No odor, but irritant to nose and eye | |
| Bulk denstiy | 650~950 g/L | 550~700 g/L | 1100~1300 g/L | 350~600 g/L | 480~600 g/L |
| Loading qty | 25~26mt/20fcl | 20mt/20fcl | 27mt/20fcl | 27mt/40HQ | 27mt/40HQ |
| Effect | Best | Normal | Bad | good | good |
| Main content | Na5P3O10 94% min | Na2O.Al2O3 | N/A | Na2O + SiO2 74% min | Na2O2SiO2 |
| Ca exchange | 158 mg/g | 295 mg/g | N/A | 320 mg/g | 550 mg/g |
| Mg exchange | N/A | 175 min | N/A | 330 mg/g | N/A |
| pH | 9.2~10.3 | 11 max | 11.3 max | 11 max | 12.0 max |
| Identical index | P2O5 content | Al3+ content | N/A | Na2O + SiO2 content | SiO2 content |
| Value of identical index | 56.5% min | 18% min | N/A | 75% min | 25% min |
| Water insoluble | 0.1% max | 100% | almost 100% | 1.5% max | 1.5% max |
| Moisture | 0.5% max | 22% max | 16% max | N/A | 5% max |
Through years of practicing and improving, now our MSD and APSM are more and more accepted in both China and many other countries.
