Silicone softener is a type of organic silicon compound used in textile, daily chemical, leather and other industries, mainly to give materials softness, smoothness, antistatic properties and other properties. Due to the wide variety of silicone softeners, silicone oils with different chemical structures correspond to different CAS numbers (Chemical Abstracts Service Registry Numbers).
CAS numbers of common silicone softeners
Silicone softeners mainly include polydimethylsiloxane (PDMS), amino silicone oil, epoxy silicone oil, polyether silicone oil, etc. Each type corresponds to a different CAS number:
| Silicone oil type | CAS number | Chemical structure/characteristics |
| Polydimethylsiloxane (PDMS) | 63148-62-9 (CH₃)₃SiO[Si(CH₃)₂O]ₙSi(CH₃)₃, | the most basic non-reactive silicone oil |
| Amino silicone oil | 71750-79-3 (common) | Contains NH₂ groups, enhances fiber affinity and improves durability |
| Epoxy silicone oil | 68607-77-2 | Contains epoxy groups and can be used for crosslinking modification |
| Polyether silicone oil | 68937-54-2 | Contains polyoxyethylene (EO)/polyoxypropylene (PO) segments and has good hydrophilicity |
| Hydrogen-containing silicone oil (PMHS) | 63148-57-2 | Contains Si-H bonds and can participate in crosslinking reactions |
Note: The same type of silicone oil may have multiple CAS numbers due to different molecular weights and modified groups, and needs to be queried based on specific products.
How to determine the CAS number of silicone softener?
Since silicone softeners are usually mixtures (such as amino silicone emulsions, polyether modified silicone oils, etc.), their CAS numbers may involve the following situations:
Pure silicone oil ingredients: such as PDMS (63148-62-9), amino silicone oil (71750-79-3).
Emulsion system: If it is a water-based emulsion, there may be no unique CAS number, and the main active ingredients need to be referred to.
Modified silicone oil: such as epoxy-modified PDMS, polyether-modified amino silicone oil, etc., need to be queried based on the modified group.
Why is the CAS number important?
Regulatory compliance:
China's "Hazardous Chemicals Catalogue" and the international GHS standard require the CAS number to be marked.
Some silicone oils (such as hydrogenated silicone oils) may be listed as hazardous chemicals and require special management.
Supply chain management:
Suppliers and customers use the CAS number to accurately identify products to avoid confusion.
Safety data (MSDS):
The CAS number is the core identifier of the MSDS, which is used to query data such as toxicity and environmental impact.
Special case description
Compound softener: If it contains multiple silicone oils (such as PDMS + amino silicone oil), the CAS numbers of all main ingredients must be listed.
How to check the CAS number?
MSDS (Safety Data Sheet): Regular suppliers should provide technical documents containing CAS numbers.
Chemical database:
PubChem (https://pubchem.ncbi.nlm.nih.gov/)
ChemSpider (http://www.chemspider.com/)
Manufacturer directory: The official websites of companies such as Momentive and Wacker provide product CAS information.
The CAS number of silicone softeners varies according to their chemical structure:
PDMS (basic silicone oil): 63148-62-9
Amino silicone oil: 71750-79-3 (common)
Hydrogen silicone oil: 63148-57-2
Other modified silicone oils need to be queried according to the specific structure.
In practical applications:
If commercial silicone emulsion is used, MSDS should be requested to confirm the CAS number.
If it is a self-developed formula, the CAS number of each silicone oil component must be separately marked to ensure compliance.
When it comes to import and export, the CAS number is one of the key information for customs declaration.
