Understanding PVP Grades for Moisturizing and Stickiness

You're asking about which grade of Polyvinylpyrrolidone (PVP), specifically PVP-K15, PVP-K17, PVP-K30, and PVP-K60, would be best for providing long-lasting moisturization (12-24 hours) with minimal stickiness, and how these grades differ beyond their molecular weight.

PVP's properties are significantly influenced by its molecular weight, indicated by the K-value. A higher K-value means a higher molecular weight.

• Lower K-values (e.g., K15, K17): These have lower molecular weights. They tend to form less rigid films and result in lower viscosity in solutions. This generally translates to less stickiness and a lighter feel.
• Higher K-values (e.g., K30, K60, K90): These have higher molecular weights. They form stronger, more substantive films and create higher viscosity. While providing stronger hold (in hair styling) or thickening, they can also be more prone to stickiness.

Based on this principle, for minimal stickiness, the lower K-value grades like PVP-K15 and PVP-K17 would generally be preferred over PVP-K30 and PVP-K60.

Regarding long-lasting moisturization (12-24 hours), PVP can contribute to skin hydration by forming a film that helps reduce water loss from the skin's surface. However, the product descriptions primarily detail the use of these PVP grades in hair styling and mask formulations, focusing on their film-forming and fixative properties. They do not provide specific data or claims about achieving 12-24 hours of moisturization on the skin or directly compare the moisturization performance of these specific grades.

In summary:

• Differences beyond molecular weight: The primary difference in performance between these PVP grades stems directly from their molecular weight (K-value), which affects film strength, viscosity, and substantivity.
• Minimal Stickiness: Lower K-values (PVP-K15, PVP-K17) are expected to be less sticky than higher K-values (PVP-K30, PVP-K60).
• Long-lasting Moisturisation: While PVP can aid moisturization through film formation, the available product information does not specify which grade provides 12-24 hours of moisturization or offer comparative data on their long-term hydrating effects on the skin.