ARTICLE INCLUDING FILTRATION MEDIA AND FLUOROPOLYMER AND METHODS OF MAKING AND USING SAME
20230347296 · 2023-11-02
Inventors
Cpc classification
B01D67/0088
PERFORMING OPERATIONS; TRANSPORTING
B01D69/02
PERFORMING OPERATIONS; TRANSPORTING
International classification
B01D69/02
PERFORMING OPERATIONS; TRANSPORTING
B01D67/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Articles including poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), fluoropolymers that do not form perfluorooctanoic acid (PFOA) when they degrade and that exhibit unexpectedly good oil repellency, are described. A method of making a fluoropolymer-containing article includes depositing a fluoropolymer-liquid mixture onto porous filtration medium by contacting the porous filtration medium with a mixture comprising a fluoropolymer and a liquid to form the treated porous filtration medium; and removing the liquid. The fluoropolymer includes poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate). Methods of using the article are further described.
Claims
1. An article comprising: a porous filtration medium; and a fluoropolymer disposed on the porous filtration medium forming a treated porous filtration medium; wherein the treated porous filtration medium has an oleophobicity of at least 1 on at least one major surface, as determined by AATCC test method 118, wherein oleophobicity ratings are rounded to nearest integer value, and wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate).
2. The article of claim 1, wherein the porous filtration medium comprises expanded polytetrafluoroethylene (ePTFE), polyurethane, polypropylene, polyethylene, polyether sulfone, polyvinylidene fluoride, polycarbonate, polyolefin, polyamide, polyester, polysulfone, polyether, acrylic polymers, methacrylic polymers, polystyrene, a cellulosic polymer, or glass, or a combination thereof.
3. The article of claim 1, wherein the treated porous filtration medium is formed by a method comprising: depositing a fluoropolymer-liquid mixture onto the porous filtration medium by contacting the porous filtration medium with a mixture comprising the fluoropolymer and a liquid; and removing the liquid.
4. The article of claim 3, wherein the liquid comprises an organic solvent.
5. The article of claim 4, wherein the organic solvent comprises methyl ethyl ketone (MEK) or a fluorosolvent comprising fluorinated ether.
6. (canceled)
7. The article of claim 4, wherein the fluoropolymer-liquid mixture comprises a fluoropolymer completely dissolved in the organic solvent.
8. The article of claim 3, wherein the fluoropolymer-liquid mixture comprises an emulsion.
9. The article of 3, wherein forming the treated porous filtration medium further comprises heating the treated porous filtration medium to a temperature of at least 70° C. for at least 1 minute.
10. (canceled)
11. The article of 3, wherein depositing the fluoropolymer-liquid mixture onto the porous filtration medium comprises immersing the porous filtration medium in the fluoropolymer-liquid mixture.
12. The article of claim 1, wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate) or a combination thereof, and wherein the number average molecular weight (Mn) of the fluoropolymer is at least 3 kDa.
13. (canceled)
14. The article of claim 1, wherein the article further comprises a support layer comprising polymeric material.
15. (canceled)
16. The article of claim 1, wherein the polymeric material comprises polypropylene, polyethylene, polyester, or nylon, or a combination thereof
17. The article of any one of the preceding claimsclaim 1, wherein the treated porous filtration medium has an oleophobicity of 2 or higher on at least one major surface.
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. The article of claim 1, wherein the article is suitable for use as a biphasic separator.
23. A method of making an article comprising a treated porous filtration medium, the method comprising: depositing a fluoropolymer-liquid mixture onto porous filtration medium by contacting the porous filtration medium with a mixture comprising a fluoropolymer and a liquid to form the treated porous filtration medium; and removing the liquid, wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate), poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), or a combination thereof.
24. The method of claim 23, wherein the liquid comprises an organic solvent.
25. The method of claim 24, wherein the organic solvent comprises methyl ethyl ketone (MEK) or a fluorosolvent comprising a fluorinated ether.
26. (canceled)
27. The article of claim 24, wherein the fluoropolymer-liquid mixture comprises a fluoropolymer completely dissolved in the organic solvent.
28. The method of claim 23, wherein the fluoropolymer-liquid mixture comprises an emulsion.
29. The method of claim 23, wherein forming the treated porous filtration medium further comprises heating the treated porous filtration medium to a temperature of at least 70° C. for at least 1 minute.
30. (canceled)
31. The method of claim 23, wherein contacting the porous filtration medium with the fluoropolymer-liquid mixture comprises immersing the porous filtration medium in the fluoropolymer-liquid mixture.
32. The method of claim 23, wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate), poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), or a combination thereof, and wherein the number average molecular weight (Mn) of the fluoropolymer is at least 3 kDa.
33. (canceled)
34. The method of claim 23, wherein the treated porous filtration medium has an oleophobicity of 1 or higher on at least one major surface, as determined by AATCC test method 118, wherein oleophobicity ratings are rounded to nearest integer value.
35. (canceled)
36. (canceled)
37. (canceled)
Description
BRIEF DESCRIPTION OF THE FIGS.
[0025]
[0026]
[0027]
[0028]
DETAILED DESCRIPTION
[0029] This disclosure describes articles including poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), fluoropolymers that do not form perfluorooctanoic acid (PFOA) when they degrade and that exhibit unexpectedly good oil repellency. The articles include a porous filtration membrane on which the fluoropolymer is disposed. This disclosure further describes methods of making the fluoropolymer-containing articles and methods of using the fluoropolymer-containing articles.
Fluoropolymers
[0030] Poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (also referred to herein as Polymer 3A or Polymer 3B) may be depicted as shown in Formula I:
##STR00001##
[0031] Poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate) (also referred to herein as Polymer 3Z) may be depicted as shown in Formula II:
##STR00002##
[0032] For Formula I or Formula II, n is typically at least 10, at least 25, at least 50, at least 70, more preferably at least 200, or most preferably at least 400. In some embodiments for Formula I or Formula II, n may be up to 500, up to 600, up to 1000, or up to 1100. For example, in an exemplary embodiment, n may be in a range of 70 to 1000. N may be in a range of 100 to 800. In another exemplary embodiment, n is in a range of 150 to 500.
[0033] Without wishing to be bound by theory, it is believed that although higher molecular weight polymers (that is, polymers having a high n of, for example, at least 1,000) may not provide improved initial oleophobicity over lower molecular weight polymers (for example, polymers having an of less than 80), porous filtration media having higher molecular weight polymers disposed thereon may show increased resistance to a drop in oleophobicity when exposed to certain liquids (such as gasoline) than porous filtration media having lower molecular weight polymers disposed thereon, and thus higher molecular weight polymers may provide improved oleophobicity during use of the articles.
[0034] Thus, in some embodiments, when the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate), the number average molecular weight (Mn) of the fluoropolymer is at least 3 kDa, at least 5 kDa, at least 10 kDa, at least 100 kDa, at least 150 kDa, at least 200 kDa, at least 250 kDa, at least 300 kDa, or at least 350 kDa. In some embodiments, when the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), the number average molecular weight (Mn) of the fluoropolymer is at least 10 kDa, at least 100 kDa, at least 150 kDa, at least 200 kDa, at least 250 kDa, at least 300 kDa, or at least 350 kDa.
[0035] Poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate) may be commercially obtained (including, for example, from Polymer Source, Montreal, Canada; or Sigma Aldrich, St. Louis Missouri) or may be synthesized using know polymerization techniques. Exemplary polymerization techniques for both polymers are described in the Examples.
Porous Filtration Medium
[0036] Any suitable porous filtration medium may be used as a part of the fluoropolymer-containing article or to form the fluoropolymer-containing article.
[0037] In some embodiments, the porous filtration medium may include expanded polytetrafluoroethylene (ePTFE), cellulose, cellulose acetate, polyurethane, polypropylene, polyethylene, polyether sulfone, polyvinylidene fluoride, polycarbonate, polyolefin, polyamide (nylon), polyester, polysulfone, polyether, acrylic polymers, methacrylic polymers, polystyrene, cellulosic polymer, or glass, or a combination thereof (for example, blends, mixtures, or copolymers thereof).
[0038] In some embodiments, the porous filtration medium may preferably include expanded polytetrafluoroethylene (ePTFE).
[0039] In some embodiments, the porous filtration medium may include a membrane, a nonwoven web, a woven web, a porous sheet, a sintered plastic, a sintered metal, a screen (including for example, a woven screen, an expanded screen, an extruded screen, etc.), or a high density mesh, or combinations thereof.
[0040] In some embodiments, the porous filtration medium may include synthetic fibers, naturally occurring fibers, or combinations thereof (for example, blends or mixtures thereof). The substrate is typically of a porous nature and of a specified and definable performance characteristic such as pore size, Frazier air permeability, and/or another suitable metric.
[0041] In some embodiments, the porous filtration medium may include a thermoplastic or a thermosetting polymer fiber. The polymers of the fiber may be present in a single polymeric material system, in a bicomponent fiber, or in a combination thereof. A bicomponent fiber may include, for example, a thermoplastic polymer. In some embodiments, a bicomponent fiber may have a core-sheath structure, including a concentric or a non-concentric structure. In some embodiments, the sheath of the bicomponent fiber may have a melting temperature lower than the melting temperature of the core such that, when heated, the sheath binds to the other fibers in the layer while the core maintains structural integrity. Additional exemplary embodiments of bicomponent fibers include side-by-side fibers or island-in-the-sea fibers.
[0042] In some embodiments, the porous filtration medium may include a cellulosic fiber including, for example, a softwood fiber (such as mercerized southern pine), a hardwood fiber (such as Eucalyptus fibers), a regenerated cellulose fiber, a mechanical pulp fiber, or a combination thereof (for example, a mixture or blend thereof).
[0043] In some embodiments, the porous filtration medium may include a glass fiber including, for example, a microglass, a chopped glass fiber, or a combination thereof (for example, a mixture or blend thereof).
Methods of Making the Fluoropolymer-Containing Articles
[0044] Fluoropolymer (poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate)) is disposed on the porous filtration medium to form a treated porous filtration medium. The treated porous filtration medium may form the fluoropolymer-containing article or a portion of the fluoropolymer-containing article.
[0045] In some embodiments, in addition to the treated porous filtration medium, the fluoropolymer-containing article may further include a support layer. The support layer may be added before or after the treatment of the porous filtration medium to form the treated porous filtration medium. Any suitable material may be used for the support layer, depending on the intended use of the article. In an exemplary embodiment, however, the support layer may include a polymer material such as polypropylene, polyethylene, polyester, or nylon, or a combination thereof (for example, a mixture or blend thereof).
[0046] In some embodiments, when a first major surface of the support layer is in contact with a first major surface of the porous filtration medium, the support layer may be added before treatment of the porous filtration medium with the fluoropolymer so that the fluoropolymer is coated on a second major surface of the porous filtration medium and a second major surface of the porous filtration medium.
[0047] In some embodiments, when the fluoropolymer is disposed on the porous filtration medium, the porous filtration medium may be formed by depositing a fluoropolymer-liquid mixture onto the porous filtration medium by contacting the porous filtration medium with a mixture including the fluoropolymer and a liquid, and removing the liquid. In some embodiments, the liquid in the fluoropolymer-liquid solution includes a solvent, that is, a liquid in which at least some of the fluoropolymer is dissolved. Alternatively, however the fluoropolymer may be applied to the porous filtration medium via an emulsion. For example, the fluoropolymer may be applied to the porous filtration medium via water-fluoropolymer emulsion.
[0048] After removal of the liquid, the fluoropolymer is disposed on at least one major surface of the porous filtration medium. For example, as described in an exemplary embodiment in the Examples, the fluoropolymer may be coated on a porous filtration medium by dipping the porous filtration medium in a mixture including the fluoropolymer and a solvent and then removing the solvent.
[0049] When the liquid includes a solvent, any suitable solvent may be used. In some embodiments, the fluoropolymer may be completely dissolved in the solvent when the fluoropolymer is applied to the porous filtration medium. Without wishing to be bound by theory, it is believed that a solution in which the fluoropolymer is completely dissolved in the solvent may be preferred when the porous filtration medium has small pore sizes (for example, less than 0.1 μm); however, a solution or an emulsion may be used when the porous filtration medium has larger pore sizes.
[0050] In some embodiments, the solvent may include an organic solvent. Alternatively, the solvent may include an inorganic solvent such as supercritical carbon dioxide (SCCO.sub.2).
[0051] Exemplary organic solvents include methyl ethyl ketone (MEK) and a fluorosolvent including, for example, a fluorinated heptane and a fluorinated ether. Exemplary fluorinated ethers include ethoxy nonafluorobutane, ethoxy nonafluoroisobutane, methoxy nonafluorobutane (also referred to as methyl nonafluorobutyl ether), and methoxy nonafluoroisobutane (also referred to as methyl nonafluoroisobutyl ether). Combinations of fluorinated ethers may also be used. In some embodiments, the fluorinated ether may include a Novec™ Engineering Fluid (3M, St. Paul, MN) such as Novec™ 7100 (which includes methyl nonafluoroisobutyl ether and methyl nonafluorobutyl ether) or Novec™ 7200 (which includes two inseparable isomers of ethoxy-nonafluorobutane).
[0052] The amount of fluoropolymer included in the fluoropolymer-liquid mixture at the time of coating may be selected depending on the desired oleophobicity. In some embodiments, the amount of fluoropolymer in the mixture may be up to 8%, up to 7%, up to 6% (w/v), up to 5% (w/v), up to 4% (w/v), up to 3% (w/v), up to 2.5% (w/v), up to 2% (w/v), up to 1.5% (w/v), or up to 1% (w/v). In some embodiments, the amount of fluoropolymer in the mixture may be at least 0.5% (w/v), at least 1% (w/v), at least 1.5% (w/v), at least 2% (w/v), at least 2.5% (w/v), at least 3% (w/v), at least 4% (w/v), at least 5% (w/v), or at least 6%.
[0053] In some embodiments, contacting the porous filtration medium with the fluoropolymer-liquid mixture includes immersing the porous filtration medium in the fluoropolymer-liquid mixture. In an exemplary embodiment, immersing the porous filtration medium in the fluoropolymer-liquid mixture includes passing the porous filtration medium through the fluoropolymer-liquid mixture so that the media enter and exits the fluoropolymer-liquid mixture at approximately the same angle.
[0054] In some embodiments, the liquid of the fluoropolymer-liquid mixture may be removed from the porous filtration medium by drying at an ambient temperature (for example, at a temperature in a range of 20° C. to 25° C.) for a time sufficient to remove the liquid (for example, a solvent).
[0055] In some embodiments, applying fluoropolymer to the porous filtration medium to form a treated porous filtration medium may further include heat treating the treated porous filtration medium. Such heating may remove the liquid from the fluoropolymer-liquid mixture after the fluoropolymer is deposited on the porous filtration medium. Moreover, without wishing to be bound by theory, it is believed that such heat treatment or “curing” may also increase the oleophobicity of the treated porous filtration medium by facilitating orientation of the fluoropolymer.
[0056] The porous filtration medium may be heated by any suitable means. In an exemplary embodiment, the porous filtration medium is heated in an oven. In another exemplary embodiment, the porous filtration medium may be heated using a hot roller, steam, an infrared heater, etc.
[0057] In some embodiments, including when the porous filtration medium is heated in an oven, the porous filtration medium may be heated at a temperature greater than the glass transition temperature of the fluoropolymer. In some embodiments, the porous filtration medium is heated at a temperature of at least 70° C., at least 80° C., at least 90° C., at least 100° C., at least 110° C., or at least 120° C. In some embodiments, the porous filtration medium is heated at a temperature of up to 130° C., up to 140° C., or up to 150° C. For example, in an exemplary embodiment, the porous filtration medium may be heated at a temperature in a range of 110° C. to 130° C. In the Examples, the porous filtration medium is heated at a temperature of 120° C.
[0058] In some embodiments, including when the porous filtration medium is heated using a hot roller, steam, an infrared heater, the porous filtration medium may be heated to a temperature greater than the glass transition temperature of the fluoropolymer. In some embodiments, the porous filtration medium is heated at a temperature to at least 70° C., at least 80° C., at least 90° C., at least 100° C., at least 110° C., or at least 120° C. In some embodiments, the porous filtration medium is heated to a temperature of up to 130° C., up to 140° C., or up to 150° C. For example, in an exemplary embodiment, the porous filtration medium may be heated to a temperature in a range of 110° C. to 130° C.
[0059] In some embodiments, the porous filtration medium may be heated for at least 1 minute, at least 2 minutes, or at least 3 minutes. In some embodiments, the porous filtration medium may be heated for up to 3 minutes, up to 4 minutes, up to 5 minutes, or up to 10 minutes. For example, in in an exemplary embodiment, the porous filtration medium may be heated for at least 1 minute and up to 10 minutes. In the Examples, the porous filtration medium is heated for 3 minutes or 5 minutes.
Treated Porous Filtration Medium
[0060] According to an embodiment, after fluoropolymer (poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate)) has been disposed on the porous filtration medium to form the treated porous filtration medium, the treated porous filtration medium is oleophobic on at least one major surface of the porous filtration medium, as determined by AATCC test method 118 and rounding the oleophobicity ratings to the nearest integer value. After fluoropolymer (poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate)) has been disposed on the porous filtration medium to form the treated porous filtration medium, the treated porous filtration medium exhibits an oleophobicity of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher, or 6 or higher on at least one major surface of the porous filtration medium, as determined by AATCC test method 118 and rounding the oleophobicity ratings to the nearest integer value. In some embodiments, the treated porous filtration medium exhibits an oleophobicity of up to 7 on at least one major surface of the porous filtration medium. The oleophobicity of the treated porous filtration medium may be 8 or lower. The oleophobicity of the treated porous filtration medium may be 3 or higher, 4 or higher, or 5 or higher. In an exemplary embodiment, the treated porous filtration medium exhibits an oleophobicity in a range of 5 to 7 or in a range of 6 to 7.
[0061] In some embodiments, the treated porous filtration medium exhibits the same oleophobicity rating on two major surfaces of the porous filtration medium. For example, the treated porous filtration medium may exhibit an oleophobicity in a range of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher, or 6 or higher, or from 5 to 7 or from 6 to 7, on two major surfaces of the porous filtration medium (for example, on a front side and a backside of the porous filtration medium). The oleophobicity of the treated porous filtration medium may be 8 or lower on two major surfaces of the porous filtration medium. The oleophobicity of the treated porous filtration medium may be 3 or higher, 4 or higher, or 5 or higher on two major surfaces of the porous filtration medium.
[0062] In some embodiments, two major surfaces of the fluoropolymer-containing article may exhibit an oleophobicity in a range of 1 or higher, 2 or higher, 3 or higher, 4 or higher, or 5 or higher, or from 5 to 7 or in a range of 6 to 7. The oleophobicity of the two major surfaces of the fluoropolymer-containing article may be 8 or lower. The oleophobicity of the two major surfaces of the fluoropolymer-containing article may be 3 or higher, 4 or higher, or 5 or higher. For example, when a first major surface of a support layer is in contact with a first major surface of the porous filtration medium, a second major surface of the porous filtration medium and a second major surface of the porous filtration medium may exhibit an oleophobicity in a range of 5 to 7 or in a range of 6 to 7.
[0063] That an oleophobicity of at least 5 or at least 6 can be obtained using poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) was surprising because, as further described in Example 1, this polymer — at both high and low number average molecular weight (Mn) — exhibits increased oleophobicity compared to other fluoropolymer methacrylates. Specifically, poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) exhibits oleophobicity like that of poly(lH,1H,2H,2H-nonafluorohexyl methacrylate); poly(lH,1H,2H,2H-nonafluorohexyl methacrylate) has an additional fluorinated carbon relative to poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) and would, therefore, be expected to have increased oleophobicity.
[0064] Moreover, an oleophobicity of at least 5 or at least 6 can also be obtained using poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), as further described in Example 3.
Methods of Using the Fluoropolymer-Containing Articles
[0065] The fluoropolymer-containing articles described herein may be used for any suitable application. In exemplary embodiments, the fluoropolymer-containing articles may be used as a biphasic separator. The two phases to be separated may be selected depending on the intended use of the article. For example, the articles may be used as an air/oil separator for air compressors, as a water/fuel separator, or as a water/oil separator. In some embodiments, the separator may be a coalescer.
Exemplary Article Aspects
[0066] Aspect 1 is an article comprising: a porous filtration medium; and a fluoropolymer disposed on the porous filtration medium forming a treated porous filtration medium; wherein the treated porous filtration medium has an oleophobicity of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher or 6 or higher on at least one major surface, as determined by AATCC test method 118 and rounding the oleophobicity ratings to the nearest integer value; and wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate). The treated porous filtration medium may have an oleophobicity of 7 or lower or 8 or lower on at least one major surface. The treated porous filtration medium may have an oleophobicity of 3 to 8, from 4 to 8, or from 5 to 7.
[0067] Aspect 2 is the article of Aspect 1 wherein the porous filtration medium comprises expanded polytetrafluoroethylene (ePTFE), polyurethane, polypropylene, polyethylene, polyether sulfone, polyvinylidene fluoride, polycarbonate, polyolefin, polyamide, polyester, polysulfone, polyether, acrylic polymers, methacrylic polymers, polystyrene, a cellulosic polymer, or glass, or a combination thereof.
[0068] Aspect 3 is the article of Aspect 1 or 2, wherein the treated porous filtration medium is formed by a method comprising: contacting the porous filtration medium with a mixture comprising the fluoropolymer and a liquid, depositing the fluoropolymer-liquid mixture onto the porous filtration medium, and removing the liquid.
[0069] Aspect 4 is the article of Aspect 3, wherein the liquid comprises an organic solvent. Aspect 5 is the article of Aspect 4, wherein the organic solvent comprises methyl ethyl ketone (MEK) or a fluorosolvent.
[0070] Aspect 6 is the article of Aspect 5, wherein the fluorosolvent comprises a fluorinated ether.
[0071] Aspect 7 is the article of any one of Aspects 4 to 6, wherein the fluoropolymer-liquid mixture comprises a fluoropolymer completely dissolved in the organic solvent.
[0072] Aspect 8 is the article of any one of Aspects 6 to 7, wherein the fluoropolymer-liquid mixture comprises an emulsion.
[0073] Aspect 9 is the article of any one of Aspects 3 to 8, wherein forming the treated porous filtration medium further comprises heat treating the treated porous filtration medium.
[0074] Aspect 10 is the article of Aspect 9, wherein heat treating the porous filtration medium comprises: heating the porous filtration medium at a temperature of at least 70° C., at least 80° C., at least 90° C., at least 100° C., or at least 120° C.; heating the porous filtration medium at a temperature of up to 130° C., up to 140° C., or up to 150° C.; heating the porous filtration medium to a temperature of at least 70° C., at least 80° C., at least 90° C., at least 100° C., or at least 120° C.; heating the porous filtration medium to a temperature of up to 130° C., up to 140° C., or up to 150° C.; heating the porous filtration medium for at least 1 minute, at least 2 minutes, or at least 3 minutes; and/or heating the porous filtration medium for up to 3 minutes, up to 4 minutes, up to 5 minutes, or up to 10 minutes.
[0075] Aspect 11 is the article of any one of Aspects 3 to 10, wherein depositing the fluoropolymer-liquid mixture onto the porous filtration medium comprises immersing the porous filtration medium in the fluoropolymer-liquid mixture.
[0076] Aspect 12 is the article of any one of the preceding Aspects, wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate), and wherein the number average molecular weight (Mn) of the fluoropolymer is at least 3 kDa, at least 5 kDa, at least 10 kDa, at least 100 kDa, at least 150 kDa, at least 200 kDa, at least 250 kDa, at least 300 kDa, or at least 350 kDa.
[0077] Aspect 13 is the article of any one of the preceding Aspects, wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), and wherein the number average molecular weight (Mn) of the fluoropolymer is at least at least 3 kDa, at least 5 kDa, 10 kDa, at least 100 kDa, at least 150 kDa, at least 200 kDa, at least 250 kDa, at least 300 kDa, or at least 350 kDa.
[0078] Aspect 14 is the article of any one of the preceding Aspects, wherein the article further comprises a support layer.
[0079] Aspect 15 is the article of Aspect 14, wherein the support layer comprises a polymeric material.
[0080] Aspect 16 is the article of Aspect 15, wherein the polymeric material comprises polypropylene, polyethylene, polyester, or nylon, or a combination thereof.
[0081] Aspect 17 is the article of any one of the preceding Aspects, wherein the treated porous filtration medium is oleophobic on two major surfaces of the porous filtration medium. The treated porous filtration medium may have an oleophobicity of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher or 6 or higher on two major surfaces of the porous filtration medium. The treated porous filtration medium may have an oleophobicity of 7 or lower or 8 or lower on two major surfaces of the porous filtration medium. The treated porous filtration medium may have an oleophobicity of 3 to 8, from 4 to 8, or from 5 to 7, on two major surfaces of the porous filtration medium.
[0082] Aspect 18 is the article of any one of the preceding Aspects, wherein the article is oleophobic on two major surfaces of the article. The article may have an oleophobicity of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher or 6 or higher on two major surfaces of the porous filtration medium. The article may have an oleophobicity of 7 or lower or 8 or lower on two major surfaces of the porous filtration medium. The article may have an oleophobicity of 3 to 8, from 4 to 8, or from 5 to 7, on two major surfaces of the porous filtration medium.
[0083] Aspect 19 is a method of using the article of any one of the preceding Aspects.
[0084] Aspect 20 is the method of Aspect 19, the method comprising using the article as a biphasic separator.
Exemplary Method Aspects
[0085] Aspect 1 is a method of making an article comprising a treated porous filtration medium, the method comprising: contacting a porous filtration medium with a mixture comprising a fluoropolymer and a liquid, depositing the fluoropolymer-liquid mixture onto the porous filtration medium to form the treated porous filtration medium, and removing the liquid, wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) or poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate).
[0086] Aspect 2 is the method of Aspect 1, wherein the liquid comprises an organic solvent.
[0087] Aspect 3 is the method of Aspect 2, wherein the organic solvent comprises methyl ethyl ketone (MEK) or a fluorosolvent.
[0088] Aspect 4 is the method of Aspect 3, wherein the fluorosolvent comprises a fluorinated ether.
[0089] Aspect 5 is the article of any one of the previous Aspects, wherein the fluoropolymer-liquid mixture comprises a fluoropolymer completely dissolved in the organic solvent.
[0090] Aspect 6 is the method of any one of the previous Aspects, wherein the fluoropolymer-liquid mixture comprises an emulsion.
[0091] Aspect 7 is the method of any one of the previous Aspects, wherein forming the treated porous filtration medium further comprises heat treating the treated porous filtration medium.
[0092] Aspect 8 is the method of Aspect 7, wherein heat treating the porous filtration medium comprises heating the porous filtration medium at a temperature of at least 70° C., at least 80° C., at least 90° C., at least 100° C., or at least 120° C.; heating the porous filtration medium at a temperature of up to 130° C., up to 140° C., or up to 150° C.; heating the porous filtration medium to a temperature of at least 70° C., at least 80° C., at least 90° C., at least 100° C., or at least 120° C.; heating the porous filtration medium to a temperature of up to 130° C., up to 140° C., or up to 150° C.; heating the porous filtration medium for at least 1 minute, at least 2 minutes, or at least 3 minutes; and/or heating the porous filtration medium for up to 3 minutes, up to 4 minutes, up to 5 minutes, or up to 10 minutes.
[0093] Aspect 9 is the method of any one of the previous Aspects, wherein contacting the porous filtration medium with the fluoropolymer-liquid mixture comprises immersing the porous filtration medium in the fluoropolymer-liquid mixture.
[0094] Aspect 10 is the method of any one of Aspects 1 to 9, wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate), and wherein the number average molecular weight (Mn) of the fluoropolymer is at least 3 kDa, at least 5 kDa, at least 10 kDa, at least 100 kDa, at least 150 kDa, at least 200 kDa, at least 250 kDa, at least 300 kDa, or at least 350 kDa.
[0095] Aspect 11 is the method of any one of Aspects 1 to 9, wherein the fluoropolymer comprises poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), and wherein the number average molecular weight (Mn) of the fluoropolymer is at least 3 kDa, at least 5 kDa, at least 10 kDa, at least 100 kDa, at least 150 kDa, at least 200 kDa, at least 250 kDa, at least 300 kDa, or at least 350 kDa.
[0096] Aspect 12 is the method of any one of the previous aspects, wherein the treated porous filtration medium is oleophobic on at least one major surface, as determined by AATCC test method 118, wherein the oleophobicity ratings are rounded to the nearest integer value. The treated porous filtration medium may have an oleophobicity of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher or 6 or higher on at least one major surface. The treated porous filtration medium may have an oleophobicity of 7 or lower or 8 or lower on at least one major surface. The treated porous filtration medium may have an oleophobicity of 3 to 8, from 4 to 8, or from 5 to 7, on at least one major surface.
[0097] Aspect 13 is the method of Aspect 12, wherein the treated porous filtration medium is oleophobic on two major surfaces of the porous filtration medium. The treated porous filtration medium may have an oleophobicity of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher or 6 or higher on two major surfaces of the porous filtration medium. The treated porous filtration medium may have an oleophobicity of 7 or lower or 8 or lower on two major surfaces of the porous filtration medium. The treated porous filtration medium may have an oleophobicity of 3 to 8, from 4 to 8, or from 5 to 7, on two major surfaces of the porous filtration medium.
[0098] Aspect 14 is the method of any one of the previous aspects, wherein the article is oleophobic on two major surfaces of the article. The article may have an oleophobicity of 1 or higher, 2 or higher, 3 or higher, 4 or higher, 5 or higher or 6 or higher on two major surfaces of the porous filtration medium. The article may have an oleophobicity of 7 or lower or 8 or lower on two major surfaces of the porous filtration medium. The article may have an oleophobicity of 3 to 8, from 4 to 8, or from 5 to 7, on two major surfaces of the porous filtration medium.
[0099] The present invention is illustrated by the following examples. It is to be understood that the particular examples, materials, amounts, and procedures are to be interpreted broadly in accordance with the scope and spirit of the invention as set forth herein.
EXAMPLES
Materials and Methods
[0100] All reagents, starting materials, and solvents used in the following examples were purchased from commercial suppliers (such as Sigma Aldrich, St. Louis, MO) and were used without further purification unless otherwise indicated.
Number Average Molecular Weight (Mn) & Weight Average Molecular Weight (Mw)
[0101] Two PHENOGEL™ Mixed C columns (5 μm, 300 mm×7.8 mm; available from Phenomenex, Torrance, CA) were used in the loop. Hexafluoroisopropanol (HFIPA) was used as the solvent at a flow rate of 0.5 mL/min. Column temperature was 45° C. A refractive index detector was used as the sole detection method. A set of PMMA polymers (poly(methyl methacrylate) standard ReadyCal set Mp 800-2,200,000 Da, from Sigma Aldrich, St. Louis, MO) with the values of the molecular weight corresponding to that of the maximum of the chromatographic peak (Mp) ranging from 800 Da to 2,200 kDa were used to generate a calibration curve, which is shown in Table 1.
[0102] All number average molecular weight (Mn), weight average molecular weight (Mw), and degree of polymerization (n) values reported herein were obtained using this calibration set and GPC parameters. Degree of polymerization (n) was determined by dividing the Mn value by the monomer's molecular weight (MW).
TABLE-US-00001 TABLE 1 Retention Time (min) Mp Mw Mn Log Mp 14.4 2200000 1890000 1650000 6.3 15.2 340000 335000 323000 5.5 15.8 608000 592000 561000 5.8 16.3 41400 40300 38100 4.6 16.9 88500 86700 83700 4.9 17.8 5050 4990 4690 3.7 18.7 9680 9590 9100 4.0 19.5 800 831 730 2.9
Glass Transition Temperature (T.SUB.g.)
[0103] Glass transition temperatures (Tg) of polymers were obtained using a Q2000 DSC (available from TA Instruments, New Castle, DE). A typical DSC run procedure was as follows: Cycle 1: room temperature to 105° C. to 23° C. Cycle 2: 23° C. to 105° C. to -90° C. Cycle 3: -90° C. to 105° C. to -90° C. Cycle 4: -90° C. to 105° C. to 23° C. The scan rate was 10° C/min. The glass transition peak was calculated using the embedded software features on the second cycle.
Fluoropolymers
General Fluoropolymer Synthesis Method
[0104] A 20 mL scintillation vial was charged with the indicated amount of monomer, azobisisobutyronitrile (AIBN), and solvent, and a magnetic stir bar was added. The vial was securely closed and sparged with Argon for 5 minutes to remove air. The vial containing the reaction mixture was placed in a custom aluminum block affixed to a hot plate/magnetic stirrer controlled utilizing a feedback probe and preheated to 65° C. The polymerization reaction was allowed to proceed overnight (at least 12 hours) at 65° C. Kinetic analysis revealed the reactions were complete within 10 hours. The reaction mixture was cooled to room temperature and diluted with solvent to a desired w/v %. The concentration of the solution was validated by pipetting 1 mL of the solution into a pre-weighed petri dish. The solvent was evaporated and the petri dish was weighed again to obtain mass of polymer.
[0105] The resulting solution was used directly for coating of samples, as further described below.
poly(2,2,2-trifluoroethyl methacrylate) (“Polymer 1A” & “Polymer 1B”)
[0106] High Molecular Weight (MW) poly(2,2,2-trifluoroethyl methacrylate) (“Polymer 1A,” Mn=25.3 kDa, Mw=61.4 kDa, Mw/Mn=2.4) was purchased from Scientific Polymer Products (Ontario, New York). Low MW poly(2,2,2-trifluoroethyl methacrylate) (“Polymer 25 1B,” Mn=3.1 kDa, Mw=8.6 kDa, Mw/Mn=2.8) was purchased from Polymer Source (Montreal, Canada).
poly(2,2,3,3,3-pentafluoropropyl methacrylate) (“Polymer 2A” & “Polymer 2B”)
[0107] High MW poly(2,2,3,3,3-pentafluoropropyl methacrylate) (“Polymer 2A”) was produced as described in the General Fluoropolymer Synthesis Method using 5 g 2,2,3,3,3-pentafluoropropyl methacrylate, 0.024 g AIBN, and 3 mL NOVEC™ 7100 Engineered Fluid. The resulting polymer exhibited Mn=11.5 kDa, Mw=23.4 kDa, Mw/Mn=2.0.
[0108] Low Molecular Weight (MW) poly(2,2,3,3,3-pentafluoropropyl methacrylate) (“Polymer 2B”) was produced as described in the General Fluoropolymer Synthesis Method using 4 g 2,2,3,3,3-pentafluoropropyl methacrylate, 0.06 g AIBN, and 3 mL tetrahydrofuran (THF). Instead of being further diluted with solvent, as described in the General Fluoropolymer Synthesis Method, polymer was precipitated from THF using hexane and vacuum filtered out using cellulose filter paper in a Buechner funnel. The polymer was washed with copious amounts of hexane and air dried. Molecular weight data was not obtained for Polymer 2B.
poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (“Polymer 3A” & “Polymer 3B”)
[0109] High Molecular Weight (MW) poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (“Polymer 3A,” Mn=30.4 kDa, Mw=73.0 kDa, Mw/Mn=2.4) was purchased from Polymer Source (Montreal, Canada). Low M W poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (“Polymer 3B,” Mn=3.9 kDa, Mw=9.8 kDa, Mw/Mn=2.5) was purchased from Polymer Source (Montreal, Canada).
poly(1H,1H,2H,2H-nonafluorohexyl methacrylate) (“Polymer 4A” & “Polymer 4B”)
[0110] High Molecular Weight (MW) poly(1H,1H,2H,2H-nonafluorohexyl methacrylate) (“Polymer 4A”) polymer (Mn=52.5 kDa, Mw=135 kDa, Mw/Mn=2.6) was purchased from Polymer Source (Montreal, Canada). Low MW poly(1H,1H,2H,2H-nonafluorohexyl methacrylate) (“Polymer 4B,” Mn=7.1 kDa, Mw=15.6 kDa, Mw/Mn=2.2) was purchased from Polymer Source (Montreal, Canada).
poly(1H,1H,2H,2H-perfluorooctyl methacrylate) (“Polymer 5”)
[0111] High Molecular Weight (MW) poly(1H,1H,2H,2H-perfluorooctyl methacrylate) (“Polymer 5A”) was produced as described in the General Fluoropolymer Synthesis Method using 2 g 1H,1H,2H,2H-perfluorooctyl methacrylate, 0.07 g AIBN, and 2 mL NOVEC™ 7200
[0112] Engineered Fluid. The resulting polymer exhibited Mn=55.2 kDa, Mw=108.0 kDa, and Mw/Mn=2.0.
Media
[0113] ePTFE media included Membrane A — Membrane D. Features of these media are shown in Table 2, below.
[0114] Air permeability in cubic feet per minute (CFM) was determined using an Air Permeability Tester Model FX3300 (Texttest AG, Schwerzenbach, Switzerland) at 0.5 inch of water of differential pressure. Air permeability may also be expressed in cm/min at 124.5 Pa differential pressure.
[0115] Thickness was determined using a Model 3W dial comparator (from B.C. Ames Incorporated, Framingham, MA) with base plate and moveable presser foot at 1.5 psi.
[0116] Pore Size was determined by capillary extrusion porometry with a Capillary Flow Porometer (from Porous Materials Inc., Ithaca, NY) using POROFIL™ (from Quantachrome Instruments, Boynton Beach, CA) as a wetting liquid and a dry up/wet up method.
TABLE-US-00002 TABLE 2 Perme- Perme- Aver- ability ability age Mem- (CFM @ (cm/min @ Thickness Thickness pore brane 0.5″ H.sub.2O) 124.5 Pa (mils) (μm) size A 0.15 +/− 4.6 +/− 9.5 +/− 241 +/− 0.2 μm 0.08 2.4 1.0 25 B 0.3-1.0 9.1-30.5 6.2 +/− 157 +/− not 2.3 58 tested C ≥2.0 ≥61 7.4-14.5 188-368 1.5 μm D 0.12-0.3 3.7-9.1 9.8-13.8 249-351 0.7 μm
Coating the Media
[0117] A coating solution including 1% — 6% (w/v) polymer in solvent (e.g., MEK or a fluorinated solvent) was poured into an aluminum petri dish to a sufficient depth so that media to be coated may be adequately submerged. The media was submerged at one end of the coating solution and pulled through the solution at a consistent angle until the entire media or substrate had been exposed to the solution. Once the media completely exited the solution at approximately the same angle as at entrance, the excess solvent on the surface and in the pores was allowed to drain for a few seconds. The coated media was then placed in a support form to prevent curling upon drying. After the coated media was visibly dry (typically about 10-30 seconds, depending on media grade), it was placed in an oven at 120° C. for 3 minutes.
Testing Oleophobicity
[0118] To determine the oleophobicity rating on a scale of 1 to 8, testing for oleophobicity was performed according to AATCC TM118-2013e2 entitled “Oil Repellency: Hydrocarbon Resistance Test,” modified by rounding the oleophobicity ratings to the nearest integer value. Briefly, drops of various oils (described in Table 3) were placed on the coated media. Each oil drop was allowed to sit for one minute before the oleo rating was recorded. If a shadow appeared under the droplet, wetting by that oil was recorded; if no shadow appeared under a droplet, no wetting was recorded. Even the slightest appearance of a shadow constituted a wetting.
[0119] Resistance to wetting by KAYDOL® (available from Sonneborn, Inc. in Parsippany, NJ) indicates an oleophobicity rating of 1; resistance to wetting by a 65:35 mixture of KAYDOL:n-hexadecane indicates an oleophobicity rating of 2; resistance to wetting by n-hexadecane indicates an oleophobicity rating of 3; resistance to wetting by n-tetradecane indicates an oleophobicity rating of 4; resistance to wetting by n-dodecane indicates an oleophobicity rating of 5; resistance to wetting by n-decane oleophobicity rating of 6; resistance to wetting by n-octane oleophobicity rating of 7; resistance to wetting by n-heptane oleophobicity rating of 8.
TABLE-US-00003 TABLE 3 Oils used in the oleophobicity test. Oil ST (mN/m) Oleo Rating Kaydol 31.5 1 65:35 Kaydol:n-hexadecane 29.6 2 n-hexadecane 27.3 3 n-tetradecane 26.4 4 n-dodecane 24.7 5 n-decane 23.5 6 n-octane 21.4 7 n-heptane 19.5 8 (ST = surface tension)
Example 1
[0120] A coating solution of 5% (w/v) or 6% (w/v) of each polymer in solvent (as indicated in Table 4) was made, and successive concentrations (for example, 5%, 4%, 3%, 2%, and 1%) were obtained via dilutions of the original solution. The coating solution was used to coat four different types of media as described in the Methods section. Oleophobicity of each media grade at each polymer concentration was evaluated. Exemplary results for high Mn poly(2,2,2-trifluoroethyl methacrylate) (“Polymer 1A”) are shown in
TABLE-US-00004 TABLE 4 Polymer Solvent Polymer 1A MEK Polymer 1B MEK Polymer 2A NOVEC ™ 7100 Polymer 2B MEK Polymer 3A NOVEC ™ 7200 Polymer 3B NOVEC ™ 7200 Polymer 4A NOVEC ™ 7200 Polymer 4B NOVEC ™ 7200 Polymer 5 NOVEC ™ 7200
[0121] The best oleophobicity rating achieved for a coating solution between 2-4% (w/v) for each of the four media grades was determined for each fluorinated methacrylate and that oleophobicity rating is plotted against the number of fluorinated carbons in the fluorinated methacrylate, as shown in
TABLE-US-00005 TABLE 5 Mn Mw Mw/Mn Polymer 1A 25300 61400 2.4 Polymer 1B 3110 8620 2.8 Polymer 2A 11500 23400 2.0 Polymer 2B (no data) (no data) (no data) Polymer 3A 30400 73000 2.4 Polymer 3B 3920 9750 2.5 Polymer 4A 52500 135000 2.6 Polymer 4B 7140 15600 2.2 Polymer 5A 55200 108000 2.0
[0122] As can be seen in
Example 2
[0123] High molecular weight poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (“Polymer 3A”) having different degrees of polymerization was produced as described in the General Fluoropolymer Synthesis Method using 5 g 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, using varying amounts of AIBN (from 0.002 g to 0.025 g), and 4 mL Novec™ 7100 Engineered Fluid.
[0124] The polymers were coated on media using a 3% (w/v) solution, and oleophobicity was tested on Membranes A-D. Similar initial oleophobicity ratings were observed at Mn values ranging from 166 kDa to 389 kDa, indicating that higher molecular weight poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) did not provide improved initial oleophobicity over lower molecular weight polymers.
Example 3
[0125] Poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate) (“Polymer 3Z”) was produced as described in the General Fluoropolymer Synthesis Method using 5 g 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 0.036 g AIBN, and 4 mL NOVEC™ 7100 Engineered Fluid. The resulting polymer exhibited Mn=390 kDa, Mw=429 kDa, and Mw/Mn=1.10.
[0126] A coating solution of 3% (w/v) in NOVEC™ 7100 Engineered Fluid was made, and the coating solution was used to coat Membranes A-D as described in the Methods section. Oleophobicity of each media grade at each polymer concentration was evaluated and was found to be comparable to high Mn poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (“Polymer 3A”), prepared as described in Example 1. Results are shown in Table 6.
TABLE-US-00006 TABLE 6 Oleophobicity Rating Membrane A Membrane B Membrane C Membrane D Polymer 3A 6 6 6 7 Polymer 3Z 6 6 5 6
[0127] The complete disclosure of all patents, patent applications, and publications, and electronically available material cited herein are incorporated by reference. In the event that any inconsistency exists between the disclosure of the present application and the disclosure(s) of any document incorporated herein by reference, the disclosure of the present application shall govern. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims.