Using Polyester / Dimethicone / IPDI Copolymer and Oil-Fix™ W in Liquid Waterproof Sunscreen

Based on the descriptions of the two products:

• Polyester / Dimethicone / IPDI Copolymer is a film builder. It creates a soft, fast-drying film on the skin that provides water and sweat resistance, making it suitable for waterproof sunscreen formulations. It helps the formula adhere to the skin and provides durability.
• Oil-Fix™ W (Oil/Silicone, Silica Dimethyl Silylate) is primarily a stabilizer for water-in-oil or water-in-silicone emulsions. It works by encapsulating water within the oil phase, which significantly increases the stability of the emulsion and allows for higher oil content. Crucially, Oil-Fix™ W also enhances the waterproof performance of the formula and helps improve the texture by reducing stickiness and providing a matte finish.

For a liquid waterproof sunscreen formulation, both ingredients can be beneficial and serve complementary roles:

• The Polyester / Dimethicone / IPDI Copolymer will create a physical film barrier on the skin surface, contributing directly to the waterproof claim by preventing water from penetrating the sunscreen layer.
• The Oil-Fix™ W will help stabilize the liquid water-in-oil emulsion, which is common for waterproof sunscreens, and further boost the waterproof properties from within the formula structure while also improving the feel on the skin.

Therefore, you can use both together in your formulation. Using both may provide enhanced stability and a higher level of waterproof performance compared to using just one.

Consider the recommended usage rates:

• Polyester / Dimethicone / IPDI Copolymer: 5-20% (for film persistence)
• Oil-Fix™ W: 2-4% (specifically for improving waterproof performance)

You can adjust the percentages within these ranges based on the desired level of waterproofness, texture, and stability for your specific liquid sunscreen formula.