Waterborne polyvinylidene difluoride coating compositions, methods of forming the same and methods for applying the same to substrate

Abstract

This article provides a coating composition comprising water; a plurality of polyvinylidene fluoride particles; and a surfactant having a hydrophobic branching degree of 5 or greater, wherein the composition is free of fluorinated surfactants.

Description

[Technical Field]

[0001] This disclosure relates to coating compositions, and more specifically to coating compositions containing polyvinylidene fluoride. [Previous Technology]

[0002] Foreword

[0003] Polyvinylidene fluoride ("PVDF") and other fluoropolymers, such as polytetrafluoroethylene ("PTFE"), are generally formed in a multi-step process. For example, U.S. Patent Application Publication No. 2021 / 0032381 describes a common method for producing PTFE involving the aqueous emulsion polymerization of fluorinated monomers. Aqueous emulsion polymerization generally uses fluorinated surfactants and may include nonionic surfactants, such as polyoxyethylene alkyl ether surfactants. Fluorinated surfactants are essential for maintaining the emulsion. Once emulsion polymerization is complete, steps are performed to concentrate the solids and remove the fluorinated surfactants. The solid fluoropolymer can then be collected and used.

[0004] PVDF is a fluoropolymer used to produce high-performance coatings that offer good solvent resistance, chemical resistance, weather resistance, and heat resistance. Unlike PTFE and other fluoropolymers, PVDF is not a fully fluorinated polymer and has a repeating chemical structure of CH2CF2. This unique chemical structure gives PVDF a low surface energy and a relatively high density of 1.8 g / cc to 1.9 g / cc. When used in aqueous dispersions, the low surface energy and high density of PVDF generally lead to particle agglomeration and separation, and therefore fluorinated surfactants are generally used. The use of such aqueous dispersions in coating applications is challenging because agglomeration and separation result in uneven particle coating on the substrate. In addition, the agglomerates tend to become densely packed within 7 days of forming the aqueous dispersion. The densely packed agglomerates can no longer be redispersed, thereby limiting the usable life of the aqueous dispersion. Therefore, it is advantageous to achieve a stable dispersion that can maintain its homogeneity or be redispersible after at least 7 days.

[0005] Fluorinated surfactants are generally required to produce stable aqueous dispersions, but the inclusion of fluorinated surfactants raises environmental concerns regarding disposal. Various attempts have been made to produce stable PVDF aqueous dispersions without fluorinated surfactants. For example, U.S. Patent Application Publication No. 2015 / 0030906 provides for the formation of aqueous dispersions of PVDF using non-fluorinated surfactants, but because PVDF is prone to rapid aggregation and separation, such dispersions should be used immediately.

[0006] In view of the above teachings, it will be unexpected to discover an aqueous dispersion of PVDF that is initially uniform and redispersible after a period of 7 days. [Summary of the Invention]

[0007] This disclosure provides an aqueous dispersion of PVDF that is initially uniform and redispersible after a 7-day period. The invention is based on the discovery that highly branched surfactants not only produce initially uniform aqueous dispersions of PVDF, but also maintain the redispersibility of PVDF after a longer shelf life. Without being bound by theory, it is believed that surfactants with a hydrophobic branching degree of 5 or greater can at least partially prevent the close aggregation of PVDF particles through steric hindrance. By preventing the close aggregation of PVDF particles, the aqueous dispersion can maintain uniform dispersion or rapidly redispersible over time.

[0008] This disclosure is particularly useful for forming coating compositions.

[0009] According to the first feature of this disclosure, the coating composition comprises water; a plurality of polyvinylidene fluoride particles; and a surfactant having a hydrophobic branching degree of 5 or greater, wherein the composition does not contain a fluorinated surfactant.

[0010] According to the second feature of this disclosure, the surfactant is a nonionic surfactant.

[0011] According to the third feature of this disclosure, the surfactant has a weight ratio of 2.0% to 15.0% relative to the polyvinylidene fluoride particles.

[0012] According to the fourth feature of this disclosure, the coating composition contains 20 wt% to 70 wt% of the polyvinylidene fluoride particles by weight of the total weight of the coating composition.

[0013] According to the fifth feature of this disclosure, the coating composition further comprises 0.1 wt% to 10.0 wt% of a dispersant, wherein the dispersant is a random copolymer of diisobutylene and maleic anhydride.

[0014] According to the sixth feature of this disclosure, the coating composition further comprises 0.1 wt% to 10.0 wt% of a dispersant, wherein the dispersant has a structure (II), wherein each AO can independently be in a random or block sequence of ethylene oxide, propylene oxide, butene oxide, and combinations thereof, and further wherein each n of structure (II) can independently be 5 to 40.

[0015] According to the seventh feature of this disclosure, the surfactant has a structure (I), wherein n of structure (I) is 3 to 11, and R1 of each n is independently selected from the group consisting of H or alkyl groups having 1 or 2 carbons.

[0016] According to the eighth feature of this disclosure, the n of structure (I) is 8 to 11 and the R1 is H.

[0017] According to the ninth feature of this disclosure, the method includes the following steps: dispersing a plurality of polyvinylidene fluoride particles in a mixture of water and a surfactant having a hydrophobic branching degree of 5 or greater, wherein the composition is free of fluorinated surfactant.

[0018] According to the tenth feature of this disclosure, a method of coating a substrate includes the step of applying a coating composition as described in technical solution 9 to the substrate.

Implementation Method

[0020] As used herein, the term "and / or" when used in a list of two or more items means that any of the listed items may be used alone, or any combination of two or more listed items may be used. For example, if a composition is described as containing components A, B, and / or C, then the composition may contain A alone; B alone; C alone; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C.

[0021] Unless otherwise stated, all ranges include end values.

[0022] As used herein, unless otherwise indicated, the term weight percentage (“wt%”) means the percentage of a component by weight in the total weight of the coating composition.

[0023] As used herein, "CAS number" is a chemical service registration number designated by the Chemical Abstracts Service. Coating composition

[0024] This disclosure relates to a coating composition. The coating composition comprises water, a plurality of polyvinylidene fluoride particles, and a surfactant having a hydrophobic branching degree of 5 or greater. The coating composition is free of fluorinated surfactants. As used herein, the term "free of" is defined as meaning that the coating composition contains 0.001 wt% or less of the material it does not contain. The coating composition may contain dispersants and / or other additives. The coating composition may contain 20 wt% or more, or 25 wt% or more, or 30 wt% or more, or 35 wt% or more, or 40 wt% or more, or 45 wt% or more, or 50 wt% or more, or 55 wt% or more, or 60 wt% or more, or 65 wt% or more, and simultaneously 70 wt% or less, or 65 wt% or less, or 60 wt% or less, or 55 wt% or less, or 50 wt% or less, or 45 wt% or less, or 40 wt% or less, or 35 wt% or less, or 30 wt% or less, or 25 wt% or less, by weight of the total coating composition. The coating composition can be used to form a coating on battery separators, and the uniform deposition of PVDF particles using an aqueous dispersion will be advantageous in other applications. Furthermore, because the coating composition does not contain fluorinated surfactants, it has a smaller associated environmental impact. polyvinylidene fluoride

[0025] The coating composition contains polyvinylidene fluoride (PVDF). PVDF is in the form of multiple particles. PVDF can be defined as homopolymer, copolymer, and trimer. PVDF can be 50 mol% or more, or 75 mol% or more, or 80 mol% or more, or 85 mol% or more of polyvinylidene fluoride copolymerized with at least one comonomer selected from the group consisting of: tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, fluoroethylene, pentafluoropropylene, tetrafluoropropylene, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, other monomers, and combinations thereof. PVDF can be 100 mol% polyvinylidene fluoride and does not contain additional comonomers. PVDF particles can have a diameter or maximum length dimension of 20 nm or larger, or 50 nm or larger, or 100 nm or larger, or 200 nm or larger, or 300 nm or larger, or 400 nm or 500 nm or smaller. PVDF can be formed by aqueous free radical emulsion polymerization, suspension polymerization, solution polymerization, and supercritical CO2 polymerization.

[0026] The coating composition may contain 20 wt% or more, or 25 wt% or more, or 30 wt% or more, or 35 wt% or more, or 40 wt% or more, or 45 wt% or more, or 50 wt% or more, or 55 wt% or more, or 60 wt% or more, or 65 wt% or more, and simultaneously, 70 wt% or less, or 65 wt% or less, or 60 wt% or less, or 55 wt% or less, or 50 wt% or less, or 45 wt% or less, or 40 wt% or less, or 35 wt% or less, or 30 wt% or less, or 25 wt% or less, based on the total weight of the coating composition. Surfactant

[0027] The coating composition includes a surfactant. The surfactant includes a hydrophobic portion ("hydrophobic body") and a hydrophilic portion. The hydrophobic body of the surfactant can be linear (i.e., straight chain) or branched (and therefore has a branching degree greater than 1). The branching degree is determined by counting the number of hydrophobic portions extending from the main chain of the hydrophobic body. The surfactant has a hydrophobic branching degree of 5 or greater, or 6 or greater, or 7 or greater, or 8 or greater, or 9 or greater. The surfactant can be a single surfactant or a mixture of surfactants. The surfactant can be characterized by structure (I): structure (I) wherein n in structure (I) is 3 to 11, and R1 of each n is independently selected from the group consisting of H or alkyl groups having 1 or 2 carbons. For example, n in structure (I) can be 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10, or 11.

[0028] The coating composition contains 0.1 wt% to 10.0 wt% of surfactants based on the total weight of the coating composition. For example, a coating composition may contain, by weight of the total coating composition, 0.1 wt% or more, or 0.5 wt% or more, or 1.0 wt% or more, or 1.5 wt% or more, or 2.0 wt% or more, or 2.5 wt% or more, or 3.0 wt% or more, or 3.5 wt% or more, or 4.0 wt% or more, or 4.5 wt% or more, or 5.0 wt% or more, or 5.5 wt% or more, or 6.0 wt% or more, or 6.5 wt% or more, or 7.0 wt% or more, or 7.5 wt% or more, or 8.0 wt% or more, or 8.5 wt% or more, or 9.0 wt% or more, or 9.5 wt% or more, and simultaneously, 10.0 wt% or less, or 9.5 wt% or less, or 9.0 wt% or less, or 8.5 wt% or less, or 8.0 wt% or less, or 8.0 wt% or less. The surfactant is present in wt% or less, or 7.5 wt% or less, or 7.0 wt% or less, or 6.5 wt% or less, or 6.0 wt% or less, or 5.5 wt% or less, or 5.0 wt% or less, or 4.5 wt% or less, or 4.0 wt% or less, or 3.5 wt% or less, or 3.0 wt% or less, or 2.5 wt% or less, or 2.0 wt% or less, or 1.5 wt% or less, or 1.0 wt% or less, or 0.5 wt% or less, or 0.2 wt% or less.

[0029] The coating composition may have 2% to 15% surfactant relative to PVDF by weight. For example, the weight ratio of surfactant to PVDF can be 2.0% or greater, or 2.5% or greater, or 3.0% or greater, or 3.5% or greater, or 4.0% or greater, or 4.5% or greater, or 5.0% or greater, or 5.5% or greater, or 6.0% or greater, or 6.5% or greater, or 7.0% or greater, or 7.5% or greater, or 8.0% or greater, or 8.5% or greater, or 9.0% or greater, or 9.5% or greater, or 10.0% or greater, or 10.5% or greater, or 11.0% or greater, or 11.5% or greater, or 12.0% or greater, or 12.5% ​​or greater, or 13.0% or greater, or 13.5% or greater, or 14.0% or greater. The percentages are: 14.5% or greater, and simultaneously: 15.0% or less, or 14.5% or less, or 14.0% or less, or 13.5% or less, or 13.0% or less, or 12.5% ​​or less, or 12.0% or less, or 11.5% or less, or 11.0% or less, or 10.5% or less, or 10.0% or less, 9.5% or less, or 9.0% or less, 8.5% or less, or 8.0% or less, 7.5% or less, or 7.0% or less, 6.5% or less, or 6.0% or less, 5.5% or less, or 5.0% or less, 4.5% or less, or 4.0% or less, 3.5% or less, or 3.0% or less, or 2.5% or less. The weight ratio of surfactant to PVDF is determined as explained in detail below. dispersant

[0030] The coating composition may contain one or more dispersants. For the purposes of this disclosure, the dispersant is a non-surfactant material that, when added to a suspension of solid particles in a liquid, promotes the dispersion of the particles or maintains the dispersed particles in the suspension. The dispersant may include inorganic, polymeric, and small molecule dispersants. The dispersant may be a copolymer of diisobutylene (CAS# 25167-70-8) and maleic anhydride (CAS# 108-31-6). In such examples, the dispersant may contain 30 wt% or more, or 35 wt% or more, or 40 wt% or more, or 45 wt% or more, or 50 wt% or more, or 55 wt% or more, or 60 wt% or more, or 65 wt% or more, and simultaneously 70 wt% or less, or 65 wt% or less, or 60 wt% or less, or 55 wt% or less, or 50 wt% or less, or 45 wt% or less, or 40 wt% or less, or 35 wt% or less, based on the total weight of the dispersant. The dispersant may contain 30 wt% or more, or 35 wt% or more, or 40 wt% or more, or 45 wt% or more, or 50 wt% or more, or 55 wt% or more, or 60 wt% or more, or 65 wt% or more, and simultaneously 70 wt% or less, or 65 wt% or less, or 60 wt% or less, or 55 wt% or less, or 50 wt% or less, or 45 wt% or less, or 40 wt% or less, or 35 wt% or less, based on the total weight of the dispersant.

[0031] In the example of the diisobutylene-maleic anhydride copolymer dispersant, the dispersant may have a weight average molecular weight of 10,000 to 30,000 Daltons. For example, the weight average molecular weight of the dispersant may be 10,000 Daltons or greater, or 11,000 Daltons or greater, or 12,000 Daltons or greater, or 13,000 Daltons or greater, or 14,000 Daltons or greater, or 15,000 Daltons or greater, or 16,000 Daltons or greater, or 17,000 Daltons or greater, or 18,000 Daltons or greater, or 19... 1,000 or more, or 20,000 or more, or 21,000 or more, or 22,000 or more, or 23,000 or more, or 24,000 or more, or 25,000 or more, or 26,000 or more, or 27,000 or more, or 28,000 or more, or 29,000 Ear thuds or greater, and simultaneously, 30,000 ear thuds or less, or 29,000 ear thuds or less, or 28,000 ear thuds or less, or 27,000 ear thuds or less, or 26,000 ear thuds or less, or 25,000 ear thuds or less, or 24,000 ear thuds or less, or 23,000 ear thuds or less, or 22,000 ear thuds or less, or 21,000 ear thuds or less. The molecular weight of the dispersant is determined using gel permeation chromatography. The molecular weight is either 20,000 or less, or 19,000 or less, or 18,000 or less, or 17,000 or less, or 16,000 or less, or 15,000 or less, or 14,000 or less, or 13,000 or less, or 12,000 or less, or 11,000 or less.

[0032] Another example of a suitable dispersant includes compounds characterized by structure (II): structure (II)

[0033] Each olefin oxide (“AO”) may independently be ethylene oxide, propylene oxide, butene oxide, and / or combinations thereof in a random or block sequence. Each n in structure (II) may independently be 5 to 40. For example, n may be 5 or greater, or 10 or greater, or 15 or greater, or 20 or greater, or 25 or greater, or 30 or greater, or 35 or greater, and simultaneously 40 or less, or 35 or less, or 30 or less, or 25 or less, or 20 or less, or 15 or less, or 10 or less, or 9 or less, or 8 or less, or 7 or less, or 6 or less. Ethylene oxide may constitute 25 wt% or more of the total weight of structure (II). For example, ethylene oxide may comprise 25 wt% or more, or 30 wt% or more, or 40 wt% or more, or 50 wt% or more, or 60 wt% or more, or 70 wt% or more, or 80 wt% or more, while simultaneously comprising 90 wt% or less, or 80 wt% or less, or 70 wt% or less, or 60 wt% or less, or 50 wt% or less, or 40 wt% or less, or 30 wt% or less.

[0034] The coating composition may contain 0 wt% or 0.1 wt% to 10.0 wt% of dispersant based on the total weight of the coating composition. For example, a coating composition may contain, by weight of the total coating composition, 0.1 wt% or more, or 0.5 wt% or more, or 1.0 wt% or more, or 1.5 wt% or more, or 2.0 wt% or more, or 2.5 wt% or more, or 3.0 wt% or more, or 3.5 wt% or more, or 4.0 wt% or more, or 4.5 wt% or more, or 5.0 wt% or more, or 5.5 wt% or more, or 6.0 wt% or more, or 6.5 wt% or more, or 7.0 wt% or more, or 7.5 wt% or more, or 8.0 wt% or more, or 8.5 wt% or more, or 9.0 wt% or more, or 9.5 wt% or more, and simultaneously, 10.0 wt% or less, or 9.5 wt% or less, or 9.0 wt% or less, or 8.5 wt% or less, or 8.0 wt% or less, or 8.0 wt% or less. Dispersant in wt% or less, or 7.5 wt% or less, or 7.0 wt% or less, or 6.5 wt% or less, or 6.0 wt% or less, or 5.5 wt% or less, or 5.0 wt% or less, or 4.5 wt% or less, or 4.0 wt% or less, or 3.5 wt% or less, or 3.0 wt% or less, or 2.5 wt% or less, or 2.0 wt% or less, or 1.5 wt% or less, or 1.0 wt% or less, or 0.5 wt% or less, or 0.2 wt% or less. Method for manufacturing coating compositions and coating substrates.

[0035] The coating composition is formed by a method comprising the steps of dispersing a plurality of polyvinylidene fluoride (PVDF) particles in a mixture of water and a surfactant having a hydrophobic branching degree of 5 or greater, wherein the composition is free of fluorinated surfactants. The dispersion of the PVDF particles in the mixture of water and surfactant can be accomplished in various ways. For example, the coating composition can be placed together with beads (e.g., glass, ZrO, Al2O3, etc.) in a grinding jar and ground for a predetermined period of time. This grinding method is advantageous when adding PVDF particles larger than the desired dispersion to the coating composition. Alternatively or concurrently, the PVDF particles can be directly mixed or stirred within the combined water and surfactant. It should be understood that the PVDF particles, surfactant, water, dispersant, and any other additives can be added together in any order.

[0036] The coating composition can be used to form a coating substrate. A method of coating a substrate may be carried out using the step of applying a coating composition to a substrate. The coating composition can be applied to the substrate in various ways. For example, the substrate may be impregnated with the composition, the composition may be sprayed onto the substrate, the substrate may be a continuous sheet passed through a bath of the coating composition, and / or other methods of applying the coating composition to the substrate. The substrate may comprise polymeric materials, metals, ceramics, amorphous materials (e.g., glass), and / or other types of materials. Examples of polymeric materials that the substrate may be may include low-density polyethylene, medium-density polyethylene, high-density polyethylene, polyolefin elastomers, copolymers of one or more α-olefins with another monomer, and other types of polymeric materials. In an exemplary application, the coating composition may be applied to a polymeric substrate to form a separator layer of a battery pack. Example Materials

[0037] The following materials are used to form an inventive example ("IE") and a comparative example ("CE").

[0038] Surfactant 1 is a surfactant having a 90 wt% aqueous solution of activator, and the n-order of structure (I) is 8 and the R1-order is H. The hydrophobic branching degree of surfactant 1 is 5. Surfactant 1 is available from The Dow Chemical Company, Midland Michigan.

[0039] Surfactant 2 is a surfactant having an aqueous solution of 90 wt% activator, and the n-order of structure (I) is 11 and the R-order is H. The hydrophobic branching degree of surfactant 2 is 5. Surfactant 2 is available from The Dow Chemical Company, Midland Michigan.

[0040] Dispersant 1 is formed of 45 wt% to 55 wt% of diisobutylene monomeric structural units, with the remainder being maleic anhydride. The weight average molecular weight of the dispersant is approximately 16,500 Daltons and it is available from Sigma Aldrich, St. Louis Missouri.

[0041] Dispersant 2 is a dispersant having structure (II), wherein each AO chain is composed of ethylene oxide units and propylene oxide units in block order, and the average repeating unit n is approximately 37 in each branch. Dispersant 2 is available from The Dow Chemical Company, Midland Michigan.

[0042] 3,5,5-trimethylhexyl ethoxide of surfactant 3-series hydrophobic branching system 4, which is available from Sigma Aldrich, St. Louis Missouri.

[0043] Surfactant 4 is a 2-ethylhexanol EO-PO nonionic surfactant with CAS number 64366-70-7 and a hydrophobic branching degree of 2. Surfactant 4 is available from The Dow Chemical Company, Midland Michigan.

[0044] Surfactant 5 is a C12-14 secondary alcohol ethylene oxide with CAS number 84133-50-6 and a hydrophobic branching degree of 2. Surfactant 5 is available from The Dow Chemical Company, Midland Michigan.

[0045] Isotridecyl ethoxide of surfactant 6 with an average hydrophobic branching degree of 4, and is available from BASF Corporation, Ludwigshafen, Germany under the name LUTENSOLTMTO.

[0046] PVDF-based polyvinylidene fluoride homopolymer particles, which can be purchased from Arkema, Colombes, France as KYNARTMHSV 900.

[0047] The ZrO beads are 0.8 to 1.2 mm diameter ZrO beads from Sinopharm Chem. Reagent Co. Ltd., China. Sample preparation

[0048] Comparative and inventive examples were prepared by loading a premixture of surfactant, PVDF powder, dispersant (IE1), and water into a grinding jar. ZrO beads were weighed and added. The jar was installed in a sand mill in Shanghai Dedong, and cooling water was started on the grinding jar before the grinding process began. The grinding process was carried out at 1400 rpm for 4 hours. After the allotted time, the ZrO beads were filtered out by passing the ground mixture through a 500-mesh Nylon sieve. The ground PVDF dispersion sample was applied to conductive tape for characterization using a NOVA™ Nanosem 630 scanning electron microscope from FEI Company. All examples were stored at approximately 23°C without stirring for 7 days to observe agglomeration and deposition. The weight ratio of surfactant to PVDF was calculated by dividing the weight in grams of surfactant present (considering any diluent in the surfactant) by the weight in grams of PVDF particles and multiplying by 100. Examples were evaluated using both visual inspection and scanning electron microscopy. Examples that could not be redispersed after storage were termed agglomerates or densely agglomerates, distinguished by the amount of material that could be released from the bottom of the container by stirring. Examples of PVDF that could be stirred to restore a uniform dispersion were classified as redispersible. Results

[0049] Table 1 provides the composition of IE1-IE5 and CE1-CE4. The components of the examples are provided in grams.

[0050] Table 1 formula CE1 CE2 CE3 CE4 IE1 IE2 IE3 IE4 IE5 Surfactant 1 0.777 2.331 0.7 0.3 Surfactant 2 0.7 Dispersant 2 0.7 Dispersant 1 0.7 Surfactant 3 0.4725 Surfactant 4 0.4725 Surfactant 5 0.4725 Surfactant 6 0.4725 PVDF 10.5 10.5 10.5 10.5 twenty one twenty one 10.5 10.5 6 Deionized water twenty four twenty four twenty four twenty four 46.8 46.7 23.8 23.8 13.7 Zirconium beads 100 100 100 100 105 105 105 105 100 The weight ratio of surfactant to PVDF 4.50% 4.50% 4.50% 4.50% 10% 10% 6% 6% 4.5%

[0051] Table 2 provides the initial dispersion appearance, morphology after 7 days of storage, and average particle size peak of the different surfactants used.

[0052] Table 2 Example Instant appearance after the grinding process 7-day storage CE1 uniform Closely bonded CE2 Non-uniform Closely bonded CE3 Non-uniform Closely bonded CE4 uniform Cohesion IE1 uniform uniform IE2 uniform Can be redistributed IE3 uniform Can be redistributed IE4 uniform Can be redistributed IE5 uniform Can be redistributed

[0053] Referring now to Tables 1 and 2, all inventive examples and comparative examples 1 and 4 exhibit a uniform milky white dispersion after the grinding process. However, after 7 days of storage at 23°C, CE1-CE4 showed phase separation, resulting in strong sedimentation at the bottom of the sample container. The sediments of CE1-CE4 could not be redispersed by manual shaking. IE1 remained uniform after 7 days of storage. IE2-IE5 showed phase separation, but the sediments could be redispersed by manual shaking. CE1-CE4 demonstrates that selecting surfactants with a hydrophobic branching degree of 4 or less, regardless of the surfactants used, could not prevent aggregation. However, IE1-IE5, all using surfactants with a hydrophobic branching degree of 5, yielded an initially uniform PVDF aqueous dispersion that was redispersible after a 7-day period. It is believed that surfactants with a hydrophobic branching degree of 6 or greater will exhibit the same anti-aggregation properties and will be redispersible due to even greater steric hindrance effects. [Simplified Explanation of the Diagram]

[0019] None

Claims

1. A coating composition comprising: water; a plurality of polyvinylidene fluoride particles; and a surfactant having structure (I):

1. wherein n in structure (I) is 3 to 11, and R1 of each n is independently selected from the group consisting of H or alkyl groups having 1 or 2 carbons, wherein the composition does not contain fluorinated surfactants.

2. The coating composition as claimed in claim 1, wherein the surfactant is a nonionic surfactant.

3. The coating composition of claim 1, wherein the surfactant is present in a weight ratio of 2.0% to 15.0% relative to the polyvinylidene fluoride particles.

4. The coating composition of claim 1, wherein the coating composition comprises 20 wt% to 70 wt% of the polyvinylidene fluoride particles by weight of the total weight of the coating composition.

5. The coating composition of claim 1, further comprising: 0.1 wt% to 10.0 wt% of a dispersant, wherein the dispersant is a random copolymer of diisobutylene and maleic anhydride.

6. The coating composition of any one of claims 1 to 5, further comprising: 0.1 wt% to 10.0 wt% of a dispersant, wherein the dispersant has structure (II):

6. Each AO can be independently composed of ethylene oxide, propylene oxide, butene oxide, and combinations thereof in a random or block sequence, and further wherein each n of structure (II) can be independently composed of 5 to 40.

7. The coating composition as claimed in claim 1, wherein the n of structure (I) is 8 to 11 and the R1 is H.

8. A method for forming a coating composition, comprising the step of dispersing a plurality of polyvinylidene fluoride particles in a mixture of water and a surfactant having structure (I):

8. wherein the n of structure (I) is 3 to 11, and the R1 of each n is independently selected from the group consisting of H or alkyl groups having 1 or 2 carbons, wherein the composition does not contain fluorinated surfactants.

9. A method of coating a substrate, comprising the steps of applying a coating composition as claimed in claim 8 to the substrate.