ALLYL ETHERS

FIELD

[0001] The present disclosure relates to fluoropolymers comprising 55 to 93 mole percent of tetrafluoroethylene and 7 to 45 mole percent of one or more perfluoro(alkyl allyl ether)s. The copolymers may contain additional comonomers.

SUMMARY

[0002] Briefly, in one aspect, the present disclosure provides a fluoropolymer comprising 55 to 93 mole percent, e.g., 70 to 85 mole% of tetrafluoroethylene and 7 to 45 mole percent, e.g., 15 to 30 mole percent of one or more perfluorinated allyl ethers selected from the group consisting of perfluorinated allyl ethers according to Formula 1 :

CF ₂ =CF-CF ₂ -0-(CF ₂ ) _m -F wherein: m = 1 to 6, based on the total moles of comonomers. In some embodiments, the fluoropolymer comprises 15 to 60 weight percent, e.g., 25 to 50 weight percent, of the one or more perfluorinated allyl ethers. In some embodiments, the combined amount of the perfluorinated allyl ethers and

tetrafluoroethylene in the fluoropolymer is at least 70 mole percent based on the total moles of comonomers.

[0003] In some embodiments, the fluoropolymer further comprises 1 to 30 mole percent of a perfluorinated alkyl vinyl ether, preferably no greater than 20 mole percent of perfluorinated alkyl vinyl ethers. In some embodiments, the perfluorinated alkyl vinyl ethers are selected from the group consisting of perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), and combinations thereof.

[0004] In some embodiments, the fluoropolymer has a melting temperature of no greater than 50 °C, preferably no greater than 25 °C, as measured according to the Tm Method. In some embodiments, the fluoropolymer is amorphous. In some embodiments, the MFI (265 °C/5 kg) is greater than 10 grams/lO minutes as measured according to MFI Method.

[0005] In some embodiments, the fluoropolymer further comprises a curesite monomer, e.g., no greater than 2 mole percent, preferably no greater than 0.5 mole percent of a cure-site monomer.

[0006] In some embodiments, the fluoropolymer comprises no greater than 10 mole%, optionally no greater than 5 mole% of vinylidene fluoride.

[0007] In another aspect, the present disclosure provides an article comprising the fluoropolymer according to any of the embodiments of the present disclosure. In some embodiments, the article comprises a surface and a layer comprising the fluoropolymer covering at least a portion of the surface.

In some embodiments, the article comprises a porous substrate and he fluoropolymer at least partially infused in the substrate. [0008] In yet another aspect, the present disclosure provides a coating comprising a solvent and the fluoropolymer according to any of the embodiments of the present disclosure dissolved or dispersed in the solvent. In some embodiments, the fluoropolymer is dispersed in the solvent and the solvent comprises water. In some embodiments, such aqueous dispersions further comprise a surfactant selected from the group consisting of nonionic surfactants, cationic surfactants, or combinations thereof. In some embodiments, the fluoropolymer is dissolved in the solvent and the solvent comprises at least one fluorinated solvent.

[0009] The above summary of the present disclosure is not intended to describe each embodiment of the present invention. The details of one or more embodiments of the invention are also set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and from the claims.

DETAILED DESCRIPTION

[0010] Materials providing oil-, water-, or dirt-repellency are desired in many applications including for use with clothing, appliance, and architectural applications. Fluorinated (meth)acrylate-based materials have been used; however, the fluorinated side chains can be hydrolyzed leading to a degradation in performance. Hexafluoropropylene oxide (HFPO) oligomers have been used, but with limited success.

[0011] Perfluorinated copolymers of tetrafluoroethylene (TFE) and perfluoro(alkyl vinyl ethers) (PAVE) may provide the desired performance. However, short chain PAVEs such a perfluoro(methyl vinyl ether) (PMVE) do not provide the desired performance; therefore, longer chain PAVEs such as perfluoro(propyl vinyl ether) (PPVE) must be used. Such longer chain PAVEs can generate undesirable amounts of perfluorinated carboxylic acids (PFCAs) during polymerization. For example, levels of C7 to C 14 PFCAs greater than 10 ppm may be generated. The removal of the PFCA's to acceptable levels (e.g. < 200 ppb) is quite difficult and expensive, and may not always be possible.

[0012] Copolymers of TFE and perfluoro(alkyl allyl ethers) (PAAEs) are known. However, such copolymers typically contain low amounts of PAAEs so as to maintain a high melting point, crystalline polymer.

[0013] For example, U.S. Patent No. 9,175,113 (“High Melting PTFE Polymers for Melt-Processing”) is directed to tetrafluoroethylene copolymers having a melting point of at least 317 °C and a melt flow index at 372 °C and a 5 kg load (MFI 372/5) of from about 0.60 to about 15 g/lO minutes. The copolymers are said to contain no more than 1.4 weight percent of a perfluorinated alkyl vinyl or allyl ether.

[0014] European Patent Application EP 3 284 762A1 (“Fluoropolymers Comprising

Tetrafluoroethylene and One or More Perfluorinated Alkyl Ether Comonomers”) is directed to tetrafluoroethylene copolymers having a melting point of about 250 to 326 °C and having an MFI 372/5 of about 0.5 to 50 grams/lO minutes. The copolymers are said to have at least 89% by weight of units derived from TFE, from about 0.5 to about 6% by weight of units derived from one or more PAAEs, and 0 to 4 wt.% of units derived from one or more co-polymerizable optional comonomers.

[0015] WO Publication No. 2018/034839 (“Tetrafluoroethylene and Perfluorinated Allyl Ether Copolymers”) is directed to copolymers of TFE and 0.2 to 12 percent by weight PAAEs, based on the total weight of the copolymer. These copolymers are said to have melting point between 220 and 285 °C and MFI (372/5) of 1 to 19 grams/ 10 minutes.

[0016] Generally, the melting point of such copolymers, which contain low amounts of PAAEs, are too high for many applications. In addition, their high melt-flow index (MFI) can limit their usefulness. For example, in some applications, low melting temperatures and/or high melt flow indices may be desired.

[0017] Surprisingly, the present inventors discovered that copolymers of TFE with greater than 10 mole percent PAAEs can provide one or more significant benefits. In some embodiments, the copolymers have a low melting point. In some embodiments, the fluoropolymer is amorphous. In some embodiments, the copolymers have a high melt-flow index.

[0018] In some embodiments, the copolymers have low levels of C7 to C20 PFCAs (e.g., less than 200 ppb). The present inventors discovered that copolymers have one or more of these features may be suitable for preparing durable, water- and oil-repellant articles.

[0019] In the fluoropolymers of the present disclosure, one or more PAAEs are copolymerized with TFE. As used herein, a copolymer of TFE and PAAE refers to copolymers resulting from the copolymerization of TFE and one or more PAAEs, and optionally, one or more other comonomers. Thus, a copolymer of TFE and PAAE comprises at least repeat units derived from TFE and repeat units derived from at least one PAAE, and optionally, repeat units derived from other comonomers.

[0020] In some embodiments, the copolymers consist of a copolymer of TFE and one or more PAAEs. In some embodiments, additional comonomers may be present. In some embodiments, the combined amount of the TFE and PAAEs in the fluoropolymer is at least 70 mole%, e.g., at least 80 mole%, at least 90 mole%, at least 95 mole%, or even at least 99 mole%, based on the total moles of comonomers.

[0021] Generally, the copolymers comprise at least 55 mole% of TFE and at least 7 mole% of one or more PAAEs based on the total number of moles. In some embodiments, the copolymers comprise least 70 mole%, or at least 80 mole%, or even at least 90 mole% of TFE.

[0022] Generally, the perfluoro(allyl ethers) are described by Formula 1:

CF ₂ =CF-CF ₂ -0-(CF ₂ ) _m -F. (1)

As used herein, such perfluoro(alkyl allyl ethers) of Formula 1 are described as MA-m, where m is the number of carbon atoms in the alkyl group. For example MA-l is perfluoro(methyl allyl ether); i.e., CF ₂ =CF-CF ₂ -0-CF3, and MA-3 is perfluoro(propyl allyl ether), i.e., CF ₂ =CF-CF ₂ -0-CF ₂ - CF ₂ - CF3.

In some embodiments, m is 1 to 4, e.g., m is 3. [0023] The fluoropolymers of the present disclosure contain at least 7 mole percent of one or more

PAAEs, wherein the mole percent is based on the total moles of all PAAEs in the fluoropolymer compared to the total moles of all comonomers. In some embodiments, the fluoropolymers comprise at least 10 mole%, 15 mole%, at least 25 mole%, or even at least 35% percent PAAEs. In some

embodiments, the fluoropolymers comprise no greater than 45 mole%, e.g., no greater than 40 mole% PAAEs.

[0024] In some embodiments, the fluoropolymers of the present disclosure contain at least 15 weight percent of one or more PAAEs, based on the total weight of fluoropolymer. In some embodiments, the fluoropolymers contain at least 20 wt.%, at least 30, or even at least 40 wt.% PAAEs. In some embodiments, the fluoropolymers contain no greater than 60, e.g., no greater than 50 wt.% PAAEs.

[0025] In some embodiments, such copolymers of TFE and PAAEs are at least partially crystalline yet have a lower melting temperature (Tm) than prior art TFE/PAAE copolymers. In some embodiments, the Tm is no greater than 150 °C, e.g., no greater than 100 °C, no greater than 50 °C, or even no greater than 25 °C. In some embodiments, the fluoropolymer is amorphous.

[0026] In some embodiments, such copolymers also have higher melt flow index (MFI) than prior art TFE/PAAE copolymers. In some embodiments, the MFI at 265 °C/5 kg (265/5) is at least 10, e.g., at least 20, or even at least 30 g/lO minutes. In some embodiments, the copolymers have a MFI (265/5) of at least 50, at least 100, or even at least 150 gm/lO minutes.

[0027] The fluoropolymers of the present disclosure may contain, optionally, units derived from further comonomers. In some embodiments, the fluoropolymers comprise no greater than 30 mole%, e.g., no greater than 20 mole%, no greater than 10 mole%, or even no greater than 5 mole% of such optional, additional comonomers. Such comonomers may be fluorinated or non-fluorinated but preferably are fluorinated, chlorinated or chlorinated and fluorinated.

[0028] Generally, the optional comonomers contain an alphaolefmic functionality, i.e. a

CX _| X2=CX3- group wherein X _| . X2 and X3 are independently from each other F, Cl or H with the proviso that at least one is H or F. In some embodiments, each of X _j , X2 and X3 is F.

[0029] The optional comonomers may include (i) other perfluorinated alpha-olefins such as hexafluoropropylene (HFP), (ii) partially fluorinated alpha olefins, (iii) F and Cl containing olefins such as chlorotrifluoroethylene, or (iv) non-fluorinated alpha olefins such as ethylene or propylene.

[0030] Copolymers including repeat units derived from vinylidene fluoride (CH2=CF2, VDF). can have lower temperature and chemical resistance. Therefore, in some embodiments, fluoropolymers of the present disclosure contain few or no units derived from VDF. For example, in some embodiments, the fluoropolymers comprise no greater than 10 mole%, e.g., no greater than 5, no greater than 3, or even no greater than 1 mole% of repeat units derived from VDF based on the total number of moles of repeat units in the fluoropolymer. [0031] In some embodiments, one or more of the optional comonomers may be functional comonomers, for example they may contain additional functional groups for example to introduce branching sites ("branching modifiers") or polar groups or end groups ("polarity modifiers"). Branching modifiers typically have a second alpha-olefmic group or are branched molecules themselves. Polarity modifiers include olefins having polar groups for example acid groups as additional functional groups.

[0032] In some embodiments, the fluoropolymer may include one or more perfluoro(alkyl vinyl ethers) (PAVE) comonomers. However, longer-chain PAVEs may generate undesired perfluoroalkanoic acids. Therefore, in some embodiments, the fluoropolymer may contain at least one of perfluoro(methyl vinyl ether) (PMVE) or perfhioro(ethyl vinyl ether) (PEVE). In some embodiments, the fluoropolymer contains PMVE. However, the amounts of such PAVEs may need to be limited; therefore, in some embodiments, the fhioropolymers contain no greater than 30 mole%, e.g., no greater than 20 mole%, no greater than 10 mole%, or even no greater than 5 mole% PAVEs. In some embodiments, the fluoropolymers are substantially free of PAVEs, i.e., the fhioropolymers contain less than 0.5 mole%, e.g., no greater than 0.1., or even no greater than 0.01 mole% of PAVEs.

[0033] In some embodiments, the fluoropolymers may include a curesite monomer (CSM), e.g., at least 0.05 mole%, at least 0.1 mole%, or even at least 0.2 mole%. However, if present, such CSM are generally present in low amounts, e.g., no greater than 2 mole%, e.g., no greater than 1 mole% or even no greater than 0.5 mole%. Generally, any known CSM may be used. In some embodiments, the CSM comprises a bromo-group, an iodo-group, or a cyano-group. Such CSMs and their methods of incorporation into fluorinated polymers are well-known.

[0034] In some embodiments, the fluoropolymers of the present disclosure do not include a curesite- group. However, as a result of typical raw material supply and manufacturing conditions, such curesite groups may be present in trace amounts, e.g., no greater than 5 parts per million (ppm) by weight based on the total weight of the fluoropolymer. In some embodiments, the fluoropolymer comprises no greater than 2 ppm, or even no greater than 1 ppm of curesite groups.

[0035] Even if no perfluorinated alkanoic acids are used in the production of fluoropolymers, e.g., if alternative fluorinated emulsifiers or no emulsifiers are being used, it has been found that perfluorinated alkanoic acids (in particular perfluorinated C6 to C12 acids) can be generated in the production of some copolymers. Perfluorinated alkanoic acids are represented by the formula F3C-(CF2)y-COOM; wherein y is an integer of 4 to 18. M is H in case of the free acid or a cation in case the acid is present as a salt. In case of perfluorooctanoic acid, y is 6 to give a total amount of carbon atoms of 8 (“C8-acid”).

[0036] Generally, the amount of perfluorinated alkanoic acids can be determined by extraction. The extraction of the perfluorinated alkanoic acids is typically done by treating the polymer sample with methanol (at 50 °C for 16 hours) separating the polymer from the liquid phase and determining the amount of acid in the separated (extracted) liquid phase.

[0037] Provided that no perfluorinated alkanoic acids are used in the production of fluoropolymers, as polymerized, the fluoropolymers according to the present disclosure are essentially free of extractable perfhiorinated alkanoic acids, in particular such acids with 6 to 20 carbon atoms. “Essentially free” in this context refers to amounts of less than 500 ppb, less than 200 ppb, less than 100 ppb, or even less than 50 ppb (based on the weight of polymer).“As polymerized” in this context means the polymerized product prior to any post-processing steps known to be useful for removing perfluorinated alkanoic acids, e.g., anion exchange.

[0038] Preferably, the polymers contain extractable perfluorooctanoic acid in an amount of less than 50 ppb and preferably less than 20 ppb (based on the weight of the polymer), for example from 2 to 20 ppb (based on the weight of the polymer).

[0039] Generally, known methods may be used to prepare the fhioropolymers of the present disclosure. In some embodiments, the copolymers described herein may be prepared by emulsion or suspension polymerization in an aqueous phase. In case of emulsion polymerization an emulsifier is used. In case of a suspension polymerization no emulsifier is used. In some embodiments emulsion polymerization is preferred as it results in stable dispersions.

[0040] Generally, the PAAEs and TFE are copolymerized in the presence of initiators and optional additional comonomers described above. The various monomers are used in effective amounts to produce a copolymer with the properties described herein. Effective amounts are within the amounts described and exemplified herein.

[0041] If fluorinated emulsifiers are employed in the aqueous emulsion polymerization, the polymerization is carried out without adding any perfluorinated alkanoic acid, and in particular the polymerization is carried out without adding perfluorinated octanoic acid. Alternative fluorinated emulsifiers or non-fhiorinated emulsifiers may be used instead. When used, a fluorinated alternative emulsifier is typically used in an amount of 0.01 % by weight to 1 % by weight based on solids (polymer content) to be achieved. Suitable alternative fluorinated emulsifiers include those that correspond to the general formula:

[R _f -0-L-C00-]iXi ⁺ wherein L represents a linear or branched or cyclic partially or fully fluorinated alkylene group or an aliphatic hydrocarbon group, Rf represents a linear or branched, partially or fully fluorinated aliphatic group or a linear or branched partially or fully fluorinated group interrupted once or more than once by an ether oxygen atom, X _j ⁺ represents a cation having the valence I, and i is 1, 2 or 3. In case the emulsifier contains partially fluorinated aliphatic groups it is referred to as a partially fluorinated emulsifier.

Preferably, the molecular weight of the emulsifier is less than 1,500 g/mole. Specific examples are described in, for example, U.S. Pat. Publ. 2007/0015937 (Hintzer et al.).

[0042] The aqueous emulsion polymerization may be initiated with a free radical initiator or a redox- type initiator. Any of the known or suitable initiators for initiating an aqueous emulsion polymerization can be used. Suitable initiators include organic as well as inorganic initiators. The amount of the polymerization initiator may suitably be selected, but it is usually from 2 to 600 ppm, based on the mass of water used in the polymerization.

[0043] The polymerization is preferably carried out by polymerizing the comonomers simultaneously. Typically, the reaction vessel is charged with the ingredients and the reaction is started by activating the initiator. In one embodiment the comonomers are then continuously fed into the reaction vessel after the reaction has started. They may be fed continuously at a constant comonomer ratio or at varying comonomer ratio.

[0044] In another embodiment, a seeded polymerization may be used to produce the copolymers. If the composition of the seed particles is different from the polymers that are formed on the seed particles a core-shell polymer is formed. That is, the polymerization is initiated in the presence of small particles of fluoropolymer, typically small PTFE particles that have been homopolymerized with TFE or produced by copolymerizing TFE with one or more perfluorinated comonomers as described above. Suitable seed lattices are described in e.g., EP 3 059 265.

[0045] The aqueous emulsion polymerization, whether done with or without seed particles, will preferably be conducted at a temperature of at least 65 °C, preferably at least 70 °C. Lower temperatures may not allow to introduce sufficient amounts of PAAE into the polymer to reach the required comonomer content. Upper temperatures may typically include temperatures of 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, or even 150 °C.

[0046] The polymerization will preferably be conducted at a pressure of at least 0.5, 1.0, 1.5, 1.75,

2.0, or even 2.5 MPa (megaPascals); at most 2.25, 2.5, 3.0, 3.5, 3.75, 4.0, or even 4.5 MPa.

[0047] The aqueous emulsion polymerization usually is carried out until the concentration of the polymer particles in the aqueous emulsion is at least 5, 10, or even 15 % by weight (also referred to as “solid content”).

[0048] In some embodiments, in the resulting dispersion, the average particle size (D50) of the polymer particles (i.e., primary particles) is at least 50, 100, or even 150 nm. In some embodiments, in the resulting dispersion, the average particle size of the polymer particles is at most 250, 275, 300, or even 350 nm. The particle sizes of dispersions can be determined by inelastic light scattering.

[0049] After the conclusion of the polymerization reaction, the dispersions may be treated by anion exchange to remove the alternative fluorinated emulsifiers if desired. Methods of removing the emulsifiers from the dispersions by anion-exchange and addition of non-ionic emulsifiers are disclosed for example in EP 1 155 055 B 1, by addition of polyelectrolytes are disclosed in WO2007/142888 or by addition of non-ionic stabilizers such as polyvinyl alcohols, polyvinyl esters and the like.

[0050] The fluoropolymer content in the dispersions may be increased by up-concentration, for example using ultrafiltration as described, for example in US 4,369,266 or by thermal decantation (as described for example in US 3,037,953) or by electrodecantation. The solid content of up-concentrated dispersions is typically about 30 to about 70 % by weight. [0051] The dispersions may further contain ingredients that may be beneficial when coating or impregnating the dispersion on a substrate, such as adhesion promoters, friction reducing agents, pigments and the like. Optional components include, for example, buffering agents and oxidizing agents as may be required or desired for the various applications.

[0052] In some embodiments of the present disclosure, the copolymers are provided in the form of a coating comprising the copolymer dissolved or dispersed in a solvent. For example, in some

embodiments, an aqueous dispersion of the copolymer may be used as a coating.

[0053] In some embodiments, such aqueous dispersions can include conventional cationic, nonionic, anionic, and/or zwitterionic (i.e., amphoteric) surfactants (i.e., emulsifiers). A mixture of surfactants may be used, e.g., containing nonionic and ionic surfactants. Suitable nonionic surfactants can have high or low HLB values, such as those available under the trade name TERGITOL from Dow DuPont, and the like. Suitable cationic surfactants include mono- or bi-tail ammonium salts. Suitable anionic surfactants include sulfonic and carboxylic aliphatic compounds and their salts, such as sodium dodecylbenzene sulphonate (available from Rhodia, France), and the like. Suitable amphoteric surfactants include cocobetaines, sulphobetaines, amine-oxides, and the like. In certain embodiments, surfactants suitable for use in the treating compositions of the present disclosure are described in International Publication No. WO 2013/162704 (Coppens et ak).

[0054] In some embodiments, the copolymers may be dissolved in a solvent, for example a solvent comprising a fluorinated organic solvent to form a coating. As used herein, "fluorinated organic solvent" is used as generally accepted in the art of organofluorine chemistry, and includes, but is not restricted to, fluorinated organic compounds generally taking the form of a carbon backbone substituted with fluorine atoms and optionally substituted with hydrogen and/or chlorine or other halogen atoms. The carbon backbone can be interrupted by heteroatoms such as divalent oxygen, trivalent nitrogen, sulfur, etc. Examples of fluorinated solvents include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), hydrofluoroethers (HFEs), hydrohalofluoroethers (HEFEs) such as hydrochlorofluoroethers (HCFEs), hydrofluoroolefins (HFOs), hydrochlorofluoroolefins (HCFOs), chlorofluorocarbons (CFCs), fluoroketones, perfluoroketones, and hydrochlorofluorocarbons (HCFCs), alone or as a mixture.

[0055] In some embodiments, the coatings may be used, for example, to laminate, coat and/or infuse into a substrate to form an article. The substrate or the treated surface thereof may be an inorganic or organic material. The substrate may be, for example a fiber, a fabric, a granule or a layer. Typical substrates include organic or inorganic fibers, preferably glass fibers, organic or inorganic fabrics, granules (such as polymer beads) and layers containing one or more organic polymers, including, for example, fluoropolymers. The fabrics may be woven or non-woven fabrics. The substrate may also be a metal or an article containing a metal surface or a fluoropolymer surface or layer, such as but not limited to PTFE surface or layers.

[0056] In some embodiments, the fluoropolymers may also be processed as solids. To provide the fluoropolymers in dry form, it must be separated from the dispersion. The fluoropolymers described herein may be collected by deliberately coagulating them from the aqueous dispersions by methods known in the art. In one embodiment, the aqueous emulsion is stirred at high shear rates to deliberately coagulate the polymers. Other salt-free methods include the addition of mineral acids. If salt content is not a problem, salts can be added as coagulating agents, such as for example, chloride salts (e.g., MgCl2) or ammonium carbonate. Agglomerating agents such as hydrocarbons like toluenes, xylenes and the like may be added to increase the particle sizes and to form agglomerates. Agglomeration may lead to particles (secondary particles) having sizes of from about 0.5 to 1.5 mm.

[0057] Drying of the coagulated and/or agglomerated polymer particles can be carried out at temperatures of, for example, from 100 °C to 300 °C. Particle sizes of coagulated particles can be determined by electron microscopy. The average particle sizes can be expressed as number average by standard particle size determination software. The particle sizes may be further increased by melt pelletizing. The particles may have a particle size (longest diameter) of from at least 2, typically from about 2 to about 10 mm.

[0058] In some embodiments, the coagulated fluoropolymers may be subjected to a fluorination treatment as known in the art to remove thermally unstable end groups. Unstable end groups include - CONH2, - COF and -COOH groups. Fluorination may be conducted to reduce the total number of those end groups to less than 100 or even less than 50 per 1 x 10^ carbon atoms in the polymer backbone. Suitable fluorination methods are described for example in

US 4,743,658 or DE 195 47 909 Al. The amount of end groups can be determined by IR spectroscopy as described for example in EP 226 668 Al . Another advantage of the present disclosure is that the polymers obtained by the polymerization have predominantly - COOH end groups and low amounts of- COF end groups. This allows easier and more effective fluorination because -COOH end groups convert more readily than -COF end groups.

[0059] Advantages and embodiments of this invention are further illustrated by way of examples. However, the examples are not meant to limit the disclosure to the examples provided. The disclosure can be practiced with other materials, ranges and embodiment within the scope of the claims.

[0060] Examples

[0061] In case the methods description refers to standards like DIN, ASTM, ISO etc. and in case the year the standard was issued is not indicated, the version that was in force in 2018 is meant. In case no version was in force in 2018 anymore, for example because the standard has not been renewed or has expired, the version in force at the date closest to 2018 is to be used.

[0062] MFI Method. The melt flow index (MFI), reported in g/lO min, was measured according to ASTM D- 1238 at a support weight of 5.0 kg. The MFI was obtained with a standardized extrusion die of 2.1 mm diameter and a length of 8.0 mm. Unless otherwise noted, a temperature of 265 °C was applied. [0063] Tm Method. Melting peaks of the fluoropolymers were determined according to ASTM 4591 by means of Perkin-Elmer DSC 7.0 under nitrogen flow and a heating rate of l0°C/min. The indicated melting temperature (Tm) refers to the melting peak maximum.

[0064] Comonomer Content Method. The comonomer content of the polymer was determined by solid state NMR. Samples were packed into a 3.2 mm rotor with a small amount of 2,2-bis(4- methylphenyl) hexafluoropropane as cross-integration standard. Diatomaceous earth was used instead of the fluoropolymer spacers in the rotor. Spectra were collected on a Varian 400 MHz NMRS solid state NMR spectrometer equipped with a 3.2 mm Varian HFXY MAS probe at 18 kHz MAS at l80°C. The

1H spectra were collected before and after the spectra.

[0065] Alternatively, the comonomer content in the polymers described can be determined by infrared spectroscopy using a Thermo Nicolet Nexus FT-IR spectrometer. HFP comonomer content - if present - can be determined as described in US 4,675,380.

[0066] Solid Content Method. The solid content (fluoropolymer content) of the dispersions can be determined gravimetrically according to ISO 12086. A correction for non-volatile inorganic salts is not carried out. The solid content of the polymer dispersions is taken as polymer content.

[0067] Particle Size Method. The latex particle size determination can be conducted by means of dynamic light scattering with a MALVERN ZETASIZER 1000 HSA in accordance to ISO/DIS 13321. The particle size is determined as volume -average and expressed as D50. Prior to the measurements, the polymer latexes as yielded from the polymerizations are diluted with 0.001 mol/L KCl-solution. The measurement temperature was 20 °C in all cases.

[0068] MA-3: CF2=CF-CF2-0-CF2-CF2-CF3 was purchased from Anles, St. Petersburg, Russia.

[0069] Example 1: A 50 L-polymerization kettle was charged with 23.5 L of ¾(), 5 kg of a seed as described in EP 3 059 265 A 1 and stirred at an agitator speed of 195 rpm. The kettle was heated up to 90 °C and purged with nitrogen. Then the following monomers were charged: MA-3 until 1.0 bar was reached, MA-3 and TFE until the pressure increased from 1.0 to 6.0 bar, with a TFE to MA-3 ratio of 0.2 by weight. The polymerization was initiated by adding 5.0 g of ammonium persulfate (APS). Over 190 minutes, 1.14 kg of TFE, 1.57 kg of MA-3 and 900 g of a 2 wt.% solution of APS was fed continuously to maintain the pressure. The reaction was stopped. The resulting polymer dispersion had a solid content of 8 wt.%. The average particle size of the polymer in the dispersion was 112 nm. The polymer was isolated by coagulation with MgC12; the incorporation of MA-3 was 10 mole%.

[0070] The polymer was amorphous. The MFI (265/5) was 220 g/lO minutes.

[0071] Treatment Procedure via“Padding” Process. The fluoropolymer was applied onto the fabric substrates by immersing the substrates in the treatment dispersion and agitating until the substrate was saturated. The saturated substrate was then run through a padder/roller to remove excess of the dispersion and to obtain a certain % Wet Pick Up (WPU), wherein: WPU = 100

[0072] For example, a WPU of 100 means that after this process the substrate absorbed 100% of its own weight of the treatment dispersion before drying). Samples were then dried and cured at 170 °C for 3 minutes.

[0073] Solids on Fabric (“SOF”). SOF is calculated based on the weight fraction of the dispersion in the formulation (A), the weight fraction of the solids of the formulation (S), and the measured wet pick up (WPU) according to the following formula:

SOF(%) = (A x S x WPU).

For example, if the fabric is treated with a formulation containing 6.7 wt.% of the fluoropolymer dispersion having a solids content of 30 wt.%, then at 50 WPU, the % SOF will be: 0.067 x 0.30 x 50 = 1% Solids on Fabric.

[0074] Spray Rating Method. The spray rating (SR) of a treated substrate is a value indicative of the dynamic repellency of the treated substrate to water that impinges on the treated substrate. The repellency was measured by Test Method 22-1996, published in the 2001 Technical Manual of the American Association of Textile Chemists and Colorists (AATCC), and is expressed in terms of a‘spray rating’ of the tested substrate. The spray rating was obtained by spraying 250 milliliters water on the substrate from a height of 15 centimeters. The wetting pattern was visually rated using a 0 to 100 scale, where 0 means complete wetting and 100 means no wetting at all. Spray rating was measured initially and after the fabric was laundered 5 or 20 times (designated as 5L or 20L respectively).

[0075] The laundering procedure consisted of placing a 400 - 900 square centimeter sheet of treated substrate in a washing machine (A Kenmore Elite washing machine) along with ballast sample (1.9 kilograms (kg) of 8-ounce fabric). A commercial detergent (“TIDE” available from Proctor & Gamble)

38 grams (g)) was added. The substrate and ballast load were washed using a short wash cycle at 40 °C, followed by a rinse cycle and centrifuging. The sample was not dried between repeat cycles. After the required cycles, the textile samples were dried in a Miele T-356 tumble drier, at a setting of“high”.

[0076] Oil Repellency Method. The oil repellency (OR) of a treated substrate is measured by the American Association of Textile Chemists and Colorists (AATCC) Standard Test Method No 118-1983, which is based on the resistance of a treated substrate to penetration by oils of varying surface tensions (see U.S. Patent No. 5,910,557). Ratings from 1 to 8 were assigned, with higher values indicating better oil repellency.

[0077] Water Repellency (WR) Method. The water repellency (WR) of a substrate was measured using a series of water-isopropyl alcohol test liquids and was expressed in terms of the "WR" rating of the treated substrate. The WR rating corresponded to the most penetrating test liquid which did not penetrate or wet the substrate surface after 15 seconds exposure. Substrates which were penetrated by or were resistant only to 100% water (0% isopropyl alcohol), the least penetrating test liquid, were given a rating of 0, whereas substrates resistant to a test liquid of 100% isopropyl alcohol (0% water), the most penetrating test liquid, were given a rating of 10. Other intermediate ratings were calculated by dividing the percent isopropyl alcohol in the test liquid by 10, e.g., a treated substrate resistant to a 70%/30% isopropyl alcohol/water blend, but not to an 80%/20% blend, would be given a rating of 7.

[0078] Performance Testing on Fabric.

[0079] Fabric A: Taslan Dobby woven nylon fabric (NTD), having a basis weight of 115 grams per square meter. The nylon fabric is characterized by the Chinese manufacturer as 70D* l60D/l66T*83T, dyed and prepared for finishing.

[0080] Fabric B: Poly Pongee woven polyester fabric (PPP), having a basis weight of 84 grams per square meter. The polyester fabric is characterized {Cby the Chinese manufacturer as

75D*75D/l45T*90T, dyed and prepared for finishing.

[0081] Samples were prepared with Fabrics A and B according to the Treatment Procedure via “Padding” Process using the fluoropolymer composition of Example 1. The results are summarized in Table 1.

Table 1: Test Results using the fluoropolymer of Example 1.

[0082] Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention.