US-12618194-B2 - Method of producing an object having a fluorinated polymer coating

Abstract

The invention relates to a method of producing an object having a fluorinated polymer coating free of per- and polyfluorinated acids and salts thereof, wherein the method comprises a step DF of depositing a fluorinated polymer coating on the object by means of plasma polymerization of a fluorinated precursor monomer and a step IG of exposing the object to an inhibiting gas which inhibits the formation of per- and polyfluorinated acids and salts thereof in or on the deposited fluorinated coating. Thereby step IG is carried out after step DF, and from the start of step DF until the end of step IG the object is treated in a substantially oxygen free atmosphere.

Inventors

• Mohammad Mokbul HOSSAIN
• Christoph ELLENBERGER
• Karim CHAKHARI

Assignees

• SEFAR AG

Dates

Publication Date

20260505

Application Date

20231025

Priority Date

20221129

Claims (20)

1. 1 . A method of producing an object having a fluorinated polymer coating free of per-and polyfluorinated acids and salts thereof, wherein the method comprises: performing a step DF of depositing a fluorinated polymer coating on the object by means of plasma polymerization of a fluorinated precursor monomer; performing a step IG of exposing the fluorinated polymer coating on the object to an inhibiting gas which inhibits the formation of per- and polyfluorinated acids and salts thereof in or on the deposited fluorinated polymer coating and, when the fluorinated polymer coating is exposed to the inhibiting gas, no plasma is present, wherein the step IG is carried out after the step DF, and wherein from the start of the step DF until the end of the step IG the object is treated in a substantially oxygen free atmosphere.
2. 2 . The method according to claim 1 , further comprising: performing a step DNF of depositing a non-fluorinated polymer coating on the object by means of plasma polymerization of a non-fluorinated precursor monomer, wherein the step DNF is carried out before and/or after the step DF.
3. 3 . The method according to claim 2 , wherein the plasma deposition processes for depositing the fluorinated polymer coating in the step DF and/or plasma deposition processes for depositing the non-fluorinated polymer coating in the step DNF are radical-dominated plasma processes and are low-pressure plasma processes and/or atmospheric plasma processes under protective atmosphere.
4. 4 . The method according to claim 2 , wherein the non-fluorinated precursor monomer in the step DNF comprises a non-fluorinated organosilane, organosiloxane, hydrocarbon, or a combination thereof.
5. 5 . The method according to claim 2 , further comprising: performing a step PT of pretreating the object by means of an atmospheric or low-pressure plasma using an inert gas and/or a reactive gas, wherein the step PT is carried out before the step DNF and/or the step DF.
6. 6 . The method according to claim 5 , wherein the step IG is carried out every time, directly, after the step DF, the step PT and/or the step DNF is carried out, to inactivate reactive plasma based species formed on the object during the steps DF, PT and/or DNF.
7. 7 . The method according to claim 5 , wherein the step PT is carried out first, the step DNF is carried out second, the step DF is carried out third, the step IG is carried out fourth, and then optionally the step DNF is carried out again, and wherein from the start of the step PT until the end of the step IG the object is treated in a substantially oxygen free atmosphere.
8. 8 . The method according to claim 7 , wherein a thickness of the non-fluorinated polymer coating is greater than that of the fluorinated polymer coating.
9. 9 . The method according to claim 2 , wherein the fluorinated polymer coating deposited on the object in the step DF has a thickness from 5 nm to 300 nm; and/or the non-fluorinated polymer coating deposited on the object in the step DNF has a thickness from 30 nm to 700 nm.
10. 10 . The method according to claim 2 , wherein a plasma power during the step DF and the step DNF is lower than 1 W/cm 2 of an electrode surface.
11. 11 . The method according to claim 10 , wherein the fluorinated polymer coating is hydrophobic and oleophobic and is free from per-and polyfluorinated acids and salts thereof according to Standard 100 by OEKO-TEX and/or DIN CEN/TS 15968:2010.
12. 12 . The method according to claim 1 , wherein the inhibiting gas in the step IG comprises hydrogen, nitrogen, hydrocarbon, or a mixture thereof.
13. 13 . The method according to claim 1 , wherein the object comprises polymeric materials of woven mesh, woven fabrics, knitted fabrics, nonwoven, nonwoven meltblown, nonwoven spunbond fabric, membranes, composite membranes and combinations thereof.
14. 14 . An object comprising a fluorinated polymer coating formed thereon by the method according to claim 1 , wherein the fluorinated polymer coating is free from per-and polyfluorinated acids and salts thereof according to Standard 100 by OEKO-TEX and/or DIN CEN/TS 15968:2010.
15. 15 . The method according to claim 1 , wherein the inhibiting gas comprises hydrocarbon.
16. 16 . The method according to claim 1 , wherein the fluorinated polymer coating is hydrophobic and oleophobic.
17. 17 . The method according to claim 16 , wherein the fluorinated precursor monomer comprises hexafluoropropene, octafluoropropene, trifluoropropene, pentafluoropropene, an acrylic monomer with three carbon atoms, or a combination thereof.
18. 18 . The method according to claim 17 , further comprising: prior to performing the step DF, performing a first step DNF of depositing a first non-fluorinated polymer coating on the object over the fluorinated polymer coating by means of plasma polymerization of a first non-fluorinated precursor monomer; and after performing the step DF and the step IG, performing a second step DNF of depositing a second non-fluorinated polymer coating on the object over the fluorinated polymer coating and the first non-fluorinated polymer coating by means of plasma polymerization of a second non-fluorinated precursor monomer, wherein, from the start of the first step DNF until the end of the second step DNF, the object is contained in a chamber with a substantially oxygen free atmosphere, wherein the plasma polymerization processes performed in the step DF, the first step DNF, and the second step DNF are low-pressure plasma processes and/or atmospheric plasma processes using a plasma power of lower than 1 W/cm 2 of an electrode surface, wherein the fluorinated polymer coating is free from per-and polyfluorinated acids and salts thereof according to Standard 100 by OEKO-TEX and/or DIN CEN/TS 15968:2010, wherein a thickness of the first non-fluorinated polymer coating and of the second non-fluorinated polymer coating is greater than that of the fluorinated polymer coating.
19. 19 . The method according to claim 18 , wherein the first non-fluorinated precursor monomer and the second non-fluorinated precursor monomer each comprise a non-fluorinated organosilane, organosiloxane, hydrocarbon, or a combination thereof.
20. 20 . The method according to claim 1 , wherein the fluorinated precursor monomer comprises a perfluorocarbon, perfluorohydrocarbon, or polyfluorohydrocarbon having three carbon atoms.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of European Patent No. EP 22 210 166.9, filed Nov. 29, 2022. The disclosure of the above application is incorporated herein by reference. The invention relates to a method of producing an object having a fluorinated polymer coating free of per- and polyfluorinated acids and salts thereof. Further the invention also relates to an object comprising a fluorinated polymer coating free of per- and polyfluorinated acids and salts thereof. BACKGROUND Anthropogenic organic compounds like per- and polyfluorinated alkyl substances are among substances of very high concern (SVHCs) and represent a large family which have been used in a variety of industries. The literature has reported the use of these compounds as processing additives and as surfactants since 1940s. These compounds, which have special properties including fire resistance and oil, stain, grease, and water repellency, have been used commonly in the production of non-stick cookware, specialized garments and textiles, stain repellents, metal plating, and fire-fighting foams. They are classified in two groups of PFAS; perfluoroalkyl sulfonic acids (PFSA) and perfluorocarboxylic acids (PFCA). These synthetic substances that do not occur naturally in the environment and PFAS including its related salts has been already detected in different types of aqueous environments with different concentration. This is not surprising at all since certain PFAS are persistent and bioaccumulate. C8 based PFAS have already been listed as regulatory substances in the EU, and perfluorooctanesulfonic acid (PFOS) has been classified as persistent organic pollutants (POPs) in 2009. Also, regulation to avoid and to ban per- and polyfluorinated acids and salts thereof exist or are in preparation. Plasma polymerization or plasma deposition processes have been a vibrant area of research as it provides a versatile route to design materials with tunable functionalities. Due to its exclusive properties of plasma polymer smart coatings like tunable wettability, self-cleaning and antireflective make them prominent in diverse applications such as biomaterials, drug delivery, adhesion, protective coatings, microelectronic devices, oil-water separation and thin film technology. Moreover, using classical wet chemical polymerization may lead to adverse effects on polymer coatings, such as non-uniform coatings, the impurities by the solvent produces defective coatings due to the presence of solvent. To avoid such issues plasma enhanced chemical vapor deposition (PECVD) is the suitable polymerization method that utilizes precursors in either liquid or gas form for rapid, pinhole free, cross-linked and dry deposition of the polymer. It is known that plasma treatment improves the crosslinking degree in polymer when compared to classical polymerization. Such a quite controlled polymerization process occurs with the assistance of plasma energy during plasma polymerization and this plasma energy is used to activate electrons, ions and radicals. Explaining more the plasma polymerization process; monomer precursors which are in vapor form are pumped to the vacuumed plasma reactor. The energy input generates then excited electrons during glow discharge and lead to break molecules into free electrons, ions, radicals and excited molecules. In a later stage these free radicals and excited molecules recombine, condense and polymerize on the substrate, and the ions and electrons crosslink or form chemical bonds with the already deposited polymer, so the properties of plasma polymers are not only determined by precursors but also by the deposition parameters. Films polymerized from perfluorinated precursors and deposited by glow discharge (plasma deposition) are taking increasingly a wide interest. In fact the deposition method is very unique and presents many advantages such as solvent free, room temperature process, controlled thickness of deposited film including surface texture and surface chemistry design through monomer selection and plasma reactor condition. However, it has been found that objects, like fabrics, that were treated by a plasma deposition processes using fluorinated precursors also may comprise a reasonable amount of per- and polyfluorinated acids and salts thereof. SUMMARY It is therefore the object of the invention to provide a method of producing an object having a fluorinated polymer coating deposited by a plasma deposition process, which is free of per- and polyfluorinated acids and salts thereof as well as to provide an object comprising a fluorinated polymer coating which is free of per- and polyfluorinated acids and salts thereof. According to the invention this object is achieved on the one hand by a method having the features of claim 1 and by an object, like a fabric, having the features of claim 15. Preferred embodiments of the invention are stated in the respective dependent claims. According to the