Polyquaternium-55 is a synthetic cationic hair-styling polymer used in cosmetic and personal-care formulations primarily for hair fixing and styling performance. It belongs to the polyquaternium family of polymers containing quaternary ammonium functionality and is particularly relevant to hair sprays, styling products, shampoos, conditioners and other hair-care formulations.
The INCI name is Polyquaternium-55, and the commonly associated CAS Number is 306769-73-3. The Korean Cosmetic Association describes it as a polymerized quaternary ammonium chloride obtained from vinylpyrrolidone, dimethylaminopropyl methacrylamide and methacryloylaminopropyl lauryldimonium chloride.
COSMILE Europe identifies Polyquaternium-55 as a synthetic ingredient whose cosmetic function is hair fixing. It is used in hair-care and nail-care products and belongs to the hair-setting polymer group.
Commercial materials include products such as Styleze™ W-17 and aqueous Polyquaternium-55 preparations. Product forms and technical characteristics can differ significantly between grades, so active content, viscosity, pH and other QC parameters should be confirmed from the applicable commercial TDS and COA.
Polyquaternium-55 is a cationic terpolymer containing three principal structural components:
The quaternary ammonium component gives the polymer its cationic character, while the polymer backbone provides film-forming and styling characteristics.
The positive charge of cationic polymers allows them to interact with negatively charged sites on hair. This interaction can help the polymer deposit onto the hair surface and create a flexible styling film.
The exact polymer composition and molecular characteristics depend on the commercial grade. Therefore, Polyquaternium-55 should be treated as a polymeric cosmetic raw material, rather than as a single discrete low-molecular-weight compound.
Polyquaternium-55 is particularly useful when a formulation requires hair hold combined with polymeric film formation.
The polymer can deposit on hair and form a film that helps maintain the desired hairstyle. Its cationic nature also provides affinity for the hair surface.
Depending on the formulation, Polyquaternium-55 can contribute to:
COSMILE Europe specifically lists hair fixing as the cosmetic function of Polyquaternium-55.
Hair styling is the principal application area for Polyquaternium-55.
A commercial Styleze™ W17 grade is described as a multifunctional styling polymer with firm hold, high humidity resistance, flexibility and conditioning benefits. It also forms a flexible, elastic and low-tack film on hair.
Polyquaternium-55 can therefore be evaluated in:
The final hold level depends on polymer concentration, formulation composition, molecular characteristics and the selected commercial grade.
Polyquaternium polymers are widely used because their cationic structures can interact with hair surfaces and support polymer deposition.
For Polyquaternium-55, the primary officially listed COSMILE function is hair fixing, while the broader polyquaternium family is recognized for film-forming and hair-setting applications.
The resulting polymer film can help maintain hairstyle structure while contributing to the sensory properties of the finished product.
Depending on the grade and formulation, the film may be designed to provide:
Hair sprays are an important application area for Polyquaternium-55.
The polymer can provide a film around hair fibers that helps maintain the desired shape after application.
Suitable formulation objectives may include:
The appropriate polymer concentration should be established through formulation testing because excessive polymer deposition can alter hair feel and spray performance.
Polyquaternium-55 is also present in commercial hair-care products such as shampoos. EPA's Chemical and Products Database links Polyquaternium-55 with numerous personal-care product categories, including shampoos, conditioners, hair styling and hair-colouring products.
In shampoo formulations, it can contribute to hair-conditioning and surface properties while supporting styling or manageability objectives.
Potential applications include:
Polyquaternium-55 can also be evaluated in conditioner systems.
Its cationic character can promote interaction with hair surfaces, while its polymeric structure can provide film-forming characteristics.
Potential benefits include:
The final conditioning effect depends on the complete formulation and the interaction with other cationic conditioners, fatty alcohols, silicones and oils.
Polyquaternium-55 has been associated with hair-colour and colour-care formulations. EPA's product-use database lists Polyquaternium-55 in hair-colouring products as well as hair-care and styling products.
It can therefore be considered in formulations where styling, conditioning and hair-surface film formation are required alongside colour-care performance.
Commercial Polyquaternium-55 products can be supplied in aqueous preparations or other grade-dependent forms.
The exact dissolution, dilution and incorporation procedure should follow the supplier's technical documentation.
When using concentrated polymer preparations, controlled dilution and adequate mixing can help achieve uniform distribution.
The addition sequence can influence polymer distribution and final formulation properties.
Polyquaternium-55 should generally be incorporated under controlled mixing conditions. Localized over-concentration should be avoided because polymeric ingredients can affect viscosity and appearance when improperly dispersed.
Commercial Polyquaternium-55 grades may have their own specified pH ranges.
For example, an FDA record for Polyquaternium-55 (10% aqueous) lists an average pH range of 3.5–5.0 and dynamic viscosity below 5,000 cP for that defined material. These values should be treated as grade-specific, not as universal specifications for every Polyquaternium-55 product.
Polyquaternium-55 can be incorporated into different hair-care systems, including shampoo and conditioner formulations.
Compatibility should be evaluated with:
The final compatibility depends on concentration, pH, ionic strength and the overall formulation architecture.
Some commercial Polyquaternium-55 styling grades are specifically promoted for humidity-resistant styling performance.
The degree of humidity resistance is formulation- and grade-dependent and should therefore be confirmed through finished-product testing rather than assumed from the INCI name alone.
Polyquaternium-55 can be supplied at different active concentrations.
For example, FDA records identify a 10% aqueous Polyquaternium-55 material. Commercial products such as Styleze™ W17 can have different technical characteristics.
The actual active concentration should always be taken from the supplier's COA/TDS.
Polyquaternium-55 can be considered for:
Polyquaternium-55 is a synthetic cationic terpolymer primarily used as a hair-fixing and styling polymer.
The commonly associated CAS Number is 306769-73-3. This CAS is supported by KCIA, EPA and FDA records.
Its primary recognized cosmetic function is hair fixing. It is used in hair styling, hair-care and related personal-care formulations.
It is a polymer involving vinylpyrrolidone, dimethylaminopropyl methacrylamide and methacryloylaminopropyl lauryldimonium chloride.
No. COSMILE Europe identifies Polyquaternium-55 as a synthetic cosmetic ingredient.
Yes. Its structure contains quaternary ammonium functionality, giving the polymer cationic characteristics.
Yes. Commercial Polyquaternium-55 styling grades are used in hair styling and hair-spray applications. EPA's database specifically associates the substance with hair sprays and hair-styling products.
Yes. EPA's Chemical and Products Database associates Polyquaternium-55 with shampoo and conditioner products.
Yes. Hair fixing is its primary recognized cosmetic function, making it suitable for hair-setting and styling formulations.
No. It is a polymeric material rather than a single discrete low-molecular-weight compound. Exact composition and molecular-weight characteristics depend on the material and grade.
Important parameters can include appearance, active/solids content, pH, viscosity, polymer composition, molecular-weight characteristics, residual monomers, microbial quality and other grade-specific QC parameters.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white powder |