Aqueous process for making fluoropolymers

Abstract

A novel aqueous polymerization process for making fluoropolymers is disclosed in which non-ionic non-fluorinated emulsifier is used to produce fluoropolymer emulsions. The emulsifiers used in the invention are those that contain segments of polyethylene glycol and / or polypropylene glycol with repeating units of 3 to 100.

Description

FIELD OF THE INVENTION [0001] The invention relates to a process for making fluoropolymers using non-fluorinated, non-ionic emulsifiers. The emulsifiers contain segments of polyethylene glycol and / or polypropylene glycol. BACKGROUND OF THE INVENTION [0002] Fluoropolymers are generally made by an aqueous dispersion process, which provides a suitable heat sink for controlling the heat of polymerization and can produce a high yield and high molecular weight relative to polymerization conducted in an organic solvent. In order to achieve stable dispersion or emulsion, a suitable surfactant or emulsifier must be employed. Fluorinated-surfactants are generally used because they can yield stable particle and high molecular weight fluoropolymers. However, the fluorinated-surfactants typically used in emulsion polymerization of fluoropolymers, such as the ammonium salt of perfluoro octanoic acid or salts of perfluoro sulfonic acids are expensive. They also present an environmental concern rel...

AI Technical Summary

Benefits of technology

The invention is about a special type of polymer that is made in water and contains a certain type of emulsifier. The emulsifier helps to keep the polymer mixed together and prevents it from clumping together. The polymer can be used to make various products, such as a special coating for a certain material. The process of making the polymer involves using a special emulsifier that helps to keep the polymer mixed together. This results in a more stable and effective polymer that can be used in various applications.

Problems solved by technology

However, the fluorinated-surfactants typically used in emulsion polymerization of fluoropolymers, such as the ammonium salt of perfluoro octanoic acid or salts of perfluoro sulfonic acids are expensive.

The ionic emulsifiers are undesired for high purity applications due to high levels extractable ions.

Furthermore, hydrocarbon sulfonates act as implicit chain transfer agent in the emulsion polymerization of fluoropolymers, as a result, it cannot be used in sufficient amount to produce small particle size latex without inhibiting such polymerizations.

Second, the particle size of emulsifier free emulsion of fluoropolymers would be large; as a result, the shelf-life of latex would be very limited.

Third, the solid content of emulsifier free latex is limited to low or moderate solids, where in fact a high solid latex is desirable in variety of commercial applications.