Water and oil repellent porous particles and methods for making the same

Abstract

This invention relates to a hydrophobic and oleophobic porous materials and processes for making the same. In a first process of the invention, a thermoplastic substrate is at least partially coated and / or impregnated with a surface treatment material. In a second process of the invention, thermoplastic particles which comprise a surface treatment material are sintered together. Preferred surface treatment materials are fluorochemicals.

Description

[0001] This is a divisional of U.S. application Ser. No. 09 / 519,590, filed Mar. 6, 2000, the entirety of which is incorporated herein by reference.1. FIELD OF THE INVENTION[0002] The invention relates to hydrophobic and / or oleophobic porous materials and to processes for making the same.2. BACKGROUND OF THE INVENTION[0003] Materials that repel water (i.e., hydrophobic materials) and materials that repel oils (i.e., oleophobic materials) are useful in a variety of applications. For example, U.S. Pat. No. 5,853,894 discloses a method that allegedly increases the ability of laboratory vessels, such as test tubes and graduated cylinders, to repel water and oils. See also, Schmidt, D. L., et al., Nature 368:39-41 (1994); and Brady, R. F., Nature 368:16-17 (1994).[0004] In other applications, porous (i.e., gas permeable) hydrophobic and oleophobic materials are desired. For example, such materials may be used to provide vents or filters that allow the passage of gases but resist the passa...

AI Technical Summary

Benefits of technology

The resulting materials exhibit improved mechanical strength and uniform porosity, enabling their use in applications previously unsuited for prior hydrophobic and oleophobic materials, while reducing material costs and minimizing leaching issues.

Problems solved by technology

Until now, however, attempts at providing hydrophobic and oleophobic porous materials have yielded materials of limited use.

Although materials with surface energies as low as 25 to 30 dynes / cm can be obtained by this method, large amounts (e.g., greater than two percent by weight of the material) of silicone oil are often required.

More important, because silicone oil can easily leach from these materials, they are of little use in applications that require a contaminate-free environment.

Unfortunately, this method is of little use in providing hydrophobic and oleophobic materials that have desirable mechanical properties such as stiffness and strength.

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