Polymer fabric

Abstract

The invention relates to a polymer fabric comprising an outer functional layer made of a first compound having hydrophobic and oleophobic properties and a second functional layer made of a second compound having hydrophobic properties, wherein the first compound and the second compound are different from each other. Furthermore, the outer functional layer is at least partially coated with the second layer. In addition, the invention relates to a method for producing a polymer fabric and an apparatus for producing a polymer fabric.

Description

TECHNICAL FIELD

[0001] The present invention relates to a polymeric fabric having hydrophobic and oleophobic properties and a method of producing a polymeric fabric having hydrophobic and oleophobic properties. Furthermore, the present invention relates to an apparatus for producing a polymeric fabric. BACKGROUND

[0002] Protection of ventilation places, devices and fittings in microfiltration applications has high requirements. One of the challenges here is to prevent harmful liquids, particles from entering the interior of the ventilation place. Liquid-repellent coatings have therefore been frequently used in many sectors due to their ability to repel a wide range of liquids from high-surface-tension liquids such as water to low-surface-tension oils.

[0003] Traditionally, long molecular chains such as C8 fluorocarbon (FC) compounds have been used in coatings to protect personnel not only from war agents but also from everyday substances such as water, oil, fuel, lubricants, cleaning solvents and other contaminants. However, due to their potentially high toxicity, legislation has been put in place to limit or prohibit their use worldwide. Alternative coatings have been developed and brought to market. In particular, short-chain C6 fluorine chemical coatings have approached traditional C8-based FC coatings in performance without high environmental risk.

[0004] The use of C6-based FCs still results in global environmental pollution due to the fact that it contains trace amounts of perfluorooctanoic acid (PFOA) and its salts and has raised concerns due to the persistence and potential bioaccumulation of these substances. Moreover, the new REACH regulation (EU / 784 / 2020) which came into force on 3 December 2020 allows the PFOA threshold to be kept below 25 ppb (parts per billion). Therefore, for health reasons, there is a general trend to avoid these chemicals. Moreover, there is still a need for next-generation superhydrophobic and oleophobic coatings with high repellency to greases.

[0005] Hexamethyldisiloxane (HMDSO) is an industry choice to replace C6 FCs as it is a non-toxic material and does not generate harmful substances during the processing. Due to its suitable vapor pressure, it is widely used as a precursor monomer for plasma processes. Carbon-rich, plasma-polymerized HMDSO (pp-HMDSO) from pure HMDSO shows promising mechanical properties such as low internal stress, good adhesion and excellent hydrophobic barrier performance. Although the water resistance provided by pp-HMDSO coatings is promising, it does not provide any oleophobic properties.

[0006] With the progress of technology in thin film technology, there is a continuous need to develop a chemical vapor deposition method to produce thin films with permanent hydrophobic and oleophobic functionalities using ultra-short chain PFAS that exhibit unique functional properties for filtration applications. The lack of suitable volatile precursors and difficulties in composition control in the coating are major obstacles to achieving this goal. SUMMARY

[0007] It is therefore an object of the present invention to provide a robust and reliable fabric, a method of manufacturing said fabric and an apparatus for producing said polymeric fabric, said fabric having hydrophobic and oleophobic properties for hygiene and filtration applications such as water separation, acoustics, medical, health care, food.

[0008] According to the invention, in one aspect, this object is achieved by a polymeric fabric having the features of claim 1 and by a method of producing a polymeric fabric having the features of claim 9 and by an apparatus for producing a polymeric fabric having the features of claim 14.

[0009] Preferred embodiments of the invention are set out in the respective dependent claims.

[0010] The polymeric fabric according to the invention comprises an outer functional layer made of a first compound having hydrophobic and oleophobic properties and a second functional layer made of a second compound having hydrophobic properties, wherein the first compound and the second compound are different from each other. Furthermore, the outer functional layer at least partially coats the second layer.

[0011] Furthermore, the method of producing a polymeric fabric according to the invention is characterized in that an outer functional layer providing hydrophobic and oleophobic properties is deposited on the polymeric fabric by means of a low-pressure plasma coating technique and a second functional layer providing hydrophobic properties is deposited on the polymeric fabric by means of a low-pressure plasma coating technique, wherein the outer functional layer and the second functional layer are different from each other. In addition, the second functional layer is deposited on the polymeric fabric before the outer functional layer is deposited on the polymeric fabric, and wherein the outer functional layer at least partially coats the second layer.

[0012] The basic idea of the invention is to deviate from the fact of the prior art system of providing one layer on the fabric with all the required properties or characteristics. Based on the invention, two layers are provided that overlap each other, wherein these layers are different from each other. Thereby, different layers with different properties can be selected. Thus, it is no longer necessary to find and use a material that provides all the required properties, but rather different materials for different layers can be combined in order that the combination provides the required properties.

[0013] Preferably, the second functional layer does not have oleophobic properties. Thus, it is clearly distinguished from the outer functional layer which provides hydrophobic and oleophobic properties. However, due to the fact that both layers are superimposed on each other, the hydrophobic properties of the outer layer do not necessarily have to be at a very high level, since the second functional layer provided underneath also provides hydrophobic properties.

[0014] In one embodiment, the outer functional layer is a plasma nanocoating which is based on per- and polyfluoroalkyl substances (PFAS) comprising only one, two or three C atoms and / or on perfluoropolyether compounds (PFPE). Furthermore, in another or combined embodiment, the second functional layer is a plasma nanocoating which is based on hexamethyldisiloxane (HMDSO) or a diamond-like carbon (DLC) layer.

[0015] As mentioned above, the use of short molecular chain C6 fluorocarbon (FC) compounds is problematic and even not allowed anymore in some regions. A direct step to replace the latter by ultra-short chain C3 to C1 fluorocarbon (FC) compounds such as per- and polyfluoroalkyl substances (PFAS) seems to be a promising solution at first sight. However, although these compounds provide hydrophobic and oleophobic properties in principle, it was recognized that problems arise when using plasma nanocoating to deposit them on a fabric. During the plasma polymer coating process, the thickness of the PFAS-based C3 to C1 fluorocarbon compound (FC) layer is very thin compared to the previous C6 to C8-based fluorocarbon compound (FC) layer. Thus, this layer provided on a fabric, e.g. a woven fabric, provides only insufficient layer and thus improvable hydrophobic properties. Surprisingly, it was recognized that even this thinner layer provides good oleophobic properties.

[0016] This observation was also made when analyzing the layer resulting from a plasma polymer coating process based on perfluoropolyether compounds (PFPE). However, compared to a plasma nanocoating based on per- and polyfluoroalkyl substances (PFAS) comprising only one, two or three C atoms, the benefit of perfluoropolyether compounds is that perfluoropolyether compounds (PFPE) are more environmentally friendly.

[0017] Based on the present invention, the outer functional layer is a plasma nanocoating which is based on per- and polyfluoroalkyl substances (PFAS) comprising only one, two or three C atoms and / or on perfluoropolyether compounds (PFPE) provided on a second functional layer having hydrophobic properties. Thus, the improvable hydrophobic properties of the outer functional layer can be improved by the second functional layer of the present invention. In other words, a layer having good hydrophobic properties is first deposited on a fabric and in a second further step an outer functional layer having hydrophobic and oleophobic properties is deposited on the fabric which has already been covered by the second functional layer. Due to this configuration, the fabric has excellent hydrophobic and oleophobic properties.

[0018] The second functional layer can be based on a hexamethyldisiloxane (HMDSO) or diamond-like carbon (DLC) layer. Using plasma polymer coating, the second functional layer can thus be formed as a pp-HMDSO base coating, i.e. a poly(dimethylsiloxane) (PDMS-like) coating, a fluorine-doped pp-HMDSO coating and / or a fluorine-doped DLC coating. When deposited by plasma polymer technology, these coatings have a sufficiently good deposition rate to produce layers that are thicker than the outer functional layer mentioned previously. Thus, due to the combination of these two-layer technologies, excellent hydrophobic and oleophobic properties can be provided to the polymer fabric by polymer plasma coating.

[0019] Preferably, the outer functional layer and / or the second functional layer are deposited by means of a low-pressure plasma coating technology. This technology is also known as plasma-enhanced chemical vapor deposition (PECVD) method. It uses a cold plasma. Thus, this technology is suitable for temperature-sensitive polymer materials such as monofilament meshes, composite membranes. Using PECVD, a highly cross-linked polymer network with functional groups incorporated into the network can be deposited, so that a high long-term stability of the modified surface can be obtained.

[0020] Generally, the polymer fabric can be any kind of fabric. In one embodiment, the polymer fabric comprises a woven carrier layer woven from first and second monofilament yarns, wherein the first and second monofilament yarns are produced from the same or different polymer materials. The provided monofilament yarns are particularly suitable for the proposed plasma-based deposition method.

[0021] To improve the filtration properties of the polymer fabric, the polymer fabric can comprise a composite membrane comprising at least a woven carrier layer and an electrospun membrane layer. The electrospun membrane layer can have a pore size between 0.20 pm and 2.0 pm. The membrane layer can be spun directly onto the woven carrier layer, or onto a substrate and transferred to the woven carrier layer later during a bonding process.

[0022] As explained, the thickness of the outer functional layer is smaller than the thickness of the second functional layer. Excellent hydrophobic and oleophobic properties can be achieved if the ratio of the thickness of the second functional layer to the thickness of the outer functional layer is about 2:1, 3:1 or more. For example, the second functional layer can have a layer thickness of 20 to 300 nm, while the outer functional layer can have a layer thickness of preferably 10 to 150 nm.

[0023] According to the method for producing polymer fabrics of the present invention, an outer functional layer providing hydrophobic and oleophobic properties is deposited on the polymer fabric by means of a low-pressure plasma coating technique, and a second functional layer providing hydrophobic properties is deposited on the polymer fabric by means of a low-pressure plasma coating technique, wherein the outer functional layer and the second functional layer are different from each other. Furthermore, the second functional layer is deposited on the polymer fabric before the outer functional layer is deposited, and wherein the outer functional layer at least partially coats the second layer.

[0024] A central idea of ​​this invention is to provide two distinct layers, one at least partially superimposed on the other. Thus, the properties of the outer functional layer can be supported by the properties of the second functional layer. Therefore, excellent results can be obtained using only one compound possessing all the desired properties, namely, excellent results in providing polymer fabrics with hydrophobic and oleophobic properties. This is particularly important if the outer functional layer is based on perfluoroalkyl and polyfluoroalkyl substances (PFAS) containing only one, two, or three carbon atoms and / or based on perfluoropolyether compounds (PFPE), which are more environmentally friendly than previously used compounds but provide relatively less favorable hydrophobic and oleophobic properties.

[0025] To improve adhesion to the second functional layer, the polymer fabric can be pretreated using non-polymerizable gases such as argon, helium, nitrogen, oxygen, and tetrafluoromethane and / or their gaseous mixtures, using low-pressure plasma technology before depositing the second functional layer.

[0026] Alternatively or concurrently, prior to the deposition of the second functional layer, the polymer fabric may undergo a two-step pretreatment, wherein in the first step, the polymer fabric is coated with a UV-curable embossing resin using gravure printing and / or slit-die coating methods, and in the second step, the surface is patterned using UV embossing and / or thermal embossing methods.

[0027] Finally, as a supplement to or alternative to the previously described pretreatment before depositing the second functional layer, the polymer fabric may be pretreated by treating it with an aqueous solution containing sodium hydroxide (NaOH).

[0028] Due to these pretreatments, the fabric surface can be chemically and / or morphologically modified before the deposition of the functional layer, resulting in plasma-polymers adhering particularly firmly to the substrate during plasma polymerization. Furthermore, surface structuring can be achieved via nanoimprinting and plasma pretreatment to improve the roll-off effect, also known as the lotus effect. Cleaning, activation, and / or texturing of the polymer fabric are achieved through one or a combination of these pretreatments, thereby increasing the adhesion of the second functional layer. Based on this invention, fabric pretreatment or cleaning is not considered as creating a layer on the fabric.

[0029] Based on the improved implementation, the outer functional layer and / or the second functional layer are deposited in a single processing step in one process to obtain a fluorine-doped HMDSO plasma nanocoating and / or a fluorine-doped DLC plasma nanocoating.

[0030] Based on the present invention, polymer fabrics with improved water resistance and oil repellency can be provided, and / or contact angles with water, diiodomethane and pentane glycol of 110° to 150° and oil grades of 5 to 8 according to AATCC 118 can be provided.

[0031] The apparatus of the present invention for producing the polymer fabric of the present invention includes a low-pressure plasma coating apparatus adapted to deposit an outer functional layer providing hydrophobic and oleophobic properties on the polymer fabric by means of a low-pressure plasma coating technique, and adapted to deposit a second functional layer providing hydrophobic properties on the polymer fabric by means of a low-pressure plasma coating technique, wherein the outer functional layer and the second functional layer are different from each other, and adapted to first deposit the second functional layer on the polymer fabric and then deposit the outer functional layer on the polymer fabric, wherein the outer functional layer at least partially coats the second layer. Attached Figure Description

[0032] The invention is further described below with reference to preferred exemplary embodiments schematically illustrated in the accompanying drawings, in which:

[0033] Figure 1 This is a schematic diagram of a polymer fabric.

[0034] Figure 2 A schematic cross-sectional view of a polymer fabric comprising a membrane (“monolayer”) according to the present invention;

[0035] Figure 3 A schematic cross-sectional view of the composite material according to the invention arranged in a so-called "sandwich" configuration;

[0036] Figure 4 A schematic cross-sectional view of a composite material according to the invention having a multilayer structure (“multilayer”);

[0037] Figure 5 A schematic cross-sectional view of the composite material according to the invention, having two different carrier layers arranged in a "hybrid" manner; and

[0038] Figure 6 This is a schematic diagram of a method for producing the polymer fabric of the present invention. Detailed Implementation

[0039] Figure 1A strong schematic diagram of the polymer fabric 100 is shown. On the left side of the diagram, the polymer fabric 100 is provided only with an outer functional layer 120, while on the right side, in addition to the outer functional layer 120, a second functional layer 110 is also provided. The concept of the invention will be further explained below based on this example.

[0040] exist Figure 1 The diagram shows a highly enlarged schematic of the polymer fabric 100, which shows two weft threads 102 and one warp thread 104.

[0041] If, as shown on the left, only a first polymer deposition based on PFAS containing 1 to 3 carbon atoms is provided, the layer will not completely cover the yarn due to the less-than-ideal deposition rate of the compound. This is particularly evident in the contact area between weft 102 and warp 104 on the left. The same result occurs if a first polymer deposition based on PFPE is provided instead of PFAS containing 1 to 3 carbon atoms.

[0042] Conversely, in addition to the outer functional layer 120, a second functional layer 110 (e.g., based on HMDSO) is provided to ensure that the fabric 100 is completely covered by the second functional layer 110 before the outer functional layer 120 is provided. This allows for better deposition of the outer functional layer 120, and even if some areas are not covered by the outer functional layer 120, they are at least covered by the second functional layer 110. Alternatively, the second functional layer 110 can be based on F-doped HMDSO, DLC, F-doped DLC, or a combination thereof.

[0043] Figure 2 A cross-sectional view of a polymer fabric is shown, here the polymer fabric serving as composite material 10 having a carrier layer 11. A membrane 12 is disposed on the carrier layer 11, which is formed and applied to the carrier layer 11 by an electrospinning method. To improve the adhesion between the membrane 12 and the carrier layer 11, the composite material may be designed to have at least one bonding point 13 that firmly bonds the two layers together. This can be a melt-bonded or adhesive bonding location in the form of a point or line. Due to the small layer thickness of the carrier material 11 and the membrane 12, the composite material can be completely penetrated by the bonding point 13 at the bonding location.

[0044] Composite material 10, and more particularly electrospun membrane 12, can be formed to be porous. The surface and pores of composite material 10 can be coated with a coating applied according to the two-step plasma coating method of the present invention, as shown in reference... Figure 1As explained, the first plasma coating of pp-HMDSO or DLC is applied solely to provide hydrophobic properties. Hydrophobic and oleophobic properties are provided after a further plasma coating is applied, providing a layer based on PFAS containing only one, two, or three C atoms and / or PFPE-based layers. An outer functional layer and a second functional layer may also be deposited in a single plasma processing step to obtain a fluorine-doped HMDSO or fluorine-doped DLC layer, thereby providing hydrophobic and oleophobic properties. Optionally, F-doped HMDSO or F-doped DLC may also be used as the second functional layer.

[0045] The surface coating of the fibers is schematically shown as a whole in the accompanying drawings by depicted dots and lines 14. The coating can also be applied to the fibers in areas within the pores of the membrane 12, which are located inside or deeper within the composite material 10. Thus, not only the macroscopic outer surface of the composite material can be coated, but also the microscopic inner surface, i.e., fibers, recesses, and uneven portions, in which case individual fibers are individually encapsulated or surrounded.

[0046] Figure 3 Another composite material 10 is shown in a so-called "sandwich" arrangement. In this case, a membrane 12 is arranged between two carrier layers 11, thereby protecting the membrane 12 between the layers, particularly from mechanical stress. In one embodiment of the sandwich arrangement, a strength of 15.6 l / m at 200 Pa can be achieved, for example. 2 The air permeability is good. Basically, sandwich, multi-layer, or mixed arrangements can achieve up to 80 l / m² at 200 Pa. 2 .s breathability.

[0047] In each possible arrangement of the layers in composite material 10, these layers can be stacked on top of each other by simple lamination. However, these layers can also be firmly bonded to each other by joint points 13, thereby obtaining the particularly reliable mechanical strength of composite material 10.

[0048] exist Figure 4 The image shows a multilayer arrangement of composite material 10 (multilayer). In this arrangement, a carrier layer 11 and a membrane layer 12 are provided, such that they are stacked and supported on top of each other in an alternating manner. Figure 4 Two carrier layers 11 and two membrane layers 12 are provided. A multilayer arrangement may also have a random number of carrier layers 11 and / or membrane layers 12. If necessary, the two membrane layers 12 may also be provided directly stacked between two or more carrier layers. Even in the case of a multilayer arrangement, the two-step plasma coating of the present invention can be provided on the microscopic surfaces of all the mutually stacked and supported membrane layers 12 and carrier layers 11. Therefore, in a multilayer structure, the two-step plasma coating of the present invention can also be provided on the inner surface of the composite material 10.

[0049] Figure 5 A variant of composite material 10 is shown, wherein a membrane 12 is disposed between a first carrier layer 11 and a second carrier layer 15. Essentially, the first carrier layer 11 may be specifically designed as a fabric, while the second carrier layer 15 differs from the first carrier layer 11 and may be specifically provided as fleece. Through such a "hybrid" arrangement, the properties of different materials can be advantageously combined in the composite material, thereby enabling filtration, protective, and sound transmission properties to be advantageously achieved in composite material 10. Figure 5 In the hybrid arrangement shown, the two-step plasma coating of the present invention can also be provided on the composite material 10, in which case plasma polymerization of the second functional layer and the outer functional layer can also occur in deeper layers (such as within pores) within the composite material 10.

[0050] Figure 6 The scheme illustrates an example of the manufacturing process of the polymer fabric of the present invention, such as a composite material including a carrier layer. A collection substrate (above figure) is provided, on which an electrospun film is formed (first production step). The electrospun film is formed according to a generally known concept and is further described below.

[0051] In the second step, the formed membrane is transferred and bonded (bonding 1) to the carrier layer, and the original collection substrate on which the electrospun membrane is formed can optionally be removed (collection substrate removal). As provided above in the figure, the carrier layer can be a mesh or a fabric.

[0052] Optionally, their second bonding (bonding 2) can be performed after the introduction of the second outer layer, followed by an optional calendering process. Thus, the film can optionally be arranged between two identical or different layers, thereby forming a sandwich structure. The second outer layer can be provided, for example, as a mesh, lining, or nonwoven material. Finally, the two-step plasma coating of the present invention is applied to at least one carrier layer and the film. Thereby, a layer providing only hydrophobic properties is first deposited, followed by a layer providing both hydrophobic and oleophobic properties. The first layer can be pp-HMDSO, fluorine-doped HMDSO, DLC, or a fluorine-doped DLC layer. The additional outer layer can be based on PFAS containing only one, two, or three C atoms and / or PFPE-based layers.

[0053] Electrospinning

[0054] The process for preparing nanofiber webs is shown in WO 2006 / 131081 and WO 2008 / 106903.

[0055] In short, electrospinning uses a high voltage to generate a charged jet of polymer solution or melt leaving a pipette. Before reaching a collecting screen, the solution jet evaporates or solidifies and is collected as interconnected webs of small fibers. One electrode is placed in the spinning solution / melt, and another is attached to the collector. In most cases, the collector is simply grounded. An electric field is applied to the end of a capillary containing the solution fluid, which is held by its surface tension. This induces charges on the surface of the liquid. The mutual repulsion of these charges and the contraction of surface charges towards the opposite electrode result in a force directly opposite to the surface tension. As the electric field strength increases, the hemispherical surface of the fluid at the capillary tip elongates, forming a cone shape called a Taylor cone. Further increasing the electric field, reaching a critical value, at which point the repulsive electrostatic force overcomes the surface tension, and the charged jet of fluid is ejected from the tip of the Taylor cone. The expelled polymer solution jet undergoes an unstable and elongating process, which allows the jet to become very long and thin. Simultaneously, the solvent evaporates, leaving behind charged polymer fibers. In the case of a melt, the ejected jet solidifies as it travels through the air.

[0056] Bonding method

[0057] Different bonding technologies are available, including hot melt gravure lamination, ultrasonic bonding, impregnation bonding, UFD fiber spraying (hot melt), and spun-web bonding.

[0058] Hot melt gravure lamination technology is industrially designed for in-line processes. Therefore, for "sandwich" type films, both bonding steps can be completed on a single production line. It utilizes a multi-purpose hot melt lamination and coating system, consisting of gravure rollers for dotting, rotating metering heads (positive / positive or negative / negative), application rollers, lamination rollers, and counter-pressure rollers.

[0059] Gravure rollers are used to apply adhesives, allowing the use of two different reactive PU-based adhesives (one for PU electrospun films and the other for PA6 films). High bond strength is achieved by sacrificing approximately 15-25% of air permeability. Careful selection of the adhesive is essential to avoid problems during the final application of the film (compliance, physical and chemical suitability, medical and food grade, etc.). Hardening of the material is observed due to the adhesive.

[0060] Impregnation bonding technology (chemical bonding) can be used to pretreat the carrier before the electrospinning process, which is sometimes preferred. Moreover, it eliminates the need for additional bonding steps, which is a major advantage. The two laminates can then be used for a second bonding process, such as hot melt, spin-web, UFD, etc., to form multi-layered pores.

[0061] UFD (Ultra-Fluorescent Dip) is a fibrous spraying technology and the most advanced technology used in hot melt adhesive coating machines. It applies laminate technology (LPT) to produce filaments of the adhesive. Heated air is used to elongate these filaments and lay them out in a random or ordered pattern. In many cases, by using UFD technology, adhesive usage can be reduced by 20-50% without adversely affecting bond strength or durability due to the high precision of the adhesive application. The non-contact mode allows for reduced chance of damage to the electrospun fibers during lamination. UFD technology is a cleaner process than hot melt gravure lamination.

[0062] Spin-web bonding technology produces a three-dimensional structure rather than a film with a closed surface. This open structure makes the resulting laminate more flexible and breathable. Webs are made from various materials: copolyamides, copolyesters, copolyolefins, polyurethanes, etc. Spin-web technology is a very simple method. The three main parameters to consider during lamination are temperature, pressure, and time.

[0063] Calendering

[0064] Calendering is used on materials such as fabrics, meshes, and laminated vents to obtain smoother, thinner materials, thereby allowing the material to pass between or under the rolls at elevated temperatures and pressures. Depending on the calendering conditions, the size and shape of the pores can be affected.

[0065] Plasma PECVD

[0066] Plasma treatment of textile materials can be applied as a finishing process for technical and medical textiles and composite materials to improve their surface properties, such as water and oil repellency. Compared with conventional wet chemical finishing of textiles, plasma technology shows advantages in terms of environmental impact. Using PECVD treatment, for example, improvements in adhesion properties, increased hydrophilicity, the introduction of specific functional groups on the surface, or changes in surface morphology can be achieved.

[0067] In plasma deposition, commonly known as plasma polymerization or PECVD, very thin polymer layers (nanoscale) can be deposited on a substrate surface. This layer is formed through the polymerization of an organic precursor gas, which polymerizes directly on the substrate surface. Compared to typical polymerization, plasma polymerization can use any monomer gas or vapor without being limited by its reactivity. Plasma polymers exhibit unconventional polymerization behavior, with branched and randomly end-capped chains and high crosslinking.

[0068] The bulk structure of plasma polymers is completely irregular, which is very different from that of conventional polymers. The difference between plasma polymer coatings (nanofilms) and conventional polymers lies in the high density of functional groups per volume, the highly cross-linked and branched plasma polymer network, the nanometer-thick coating (<200nm), the high adhesion between the coating and the substrate, and the lack of change in the bulk properties of the substrate. The substrate can be a polymer fabric.

[0069] According to the invention, plasma processing can be performed in a plasma chamber having multiple rollers and / or expanders in a roll-to-roll system, the roll-to-roll system operating at a radio frequency of preferably about 13 MHz to 14 MHz, preferably about 13.5 MHz, or using a direct current (DC) power supply.

[0070] One embodiment of the invention may be as follows: First, a pretreatment is performed for a period of approximately 2 to 5 minutes at a base pressure preferably from about 70 mTorr to about 200 mTorr, at a temperature preferably from about 20°C to about 60°C, and at a power output preferably from about 500 watts to about 1800 watts. Then, a first coating step is performed for a period of approximately 2 to 5 minutes at a base pressure preferably from about 15 mTorr to about 150 mTorr, at a temperature preferably from about 20°C to about 60°C, and at a power output preferably from about 100 watts to about 1000 watts. Next, a second coating step is performed for a period of approximately 2 to 5 minutes at a base pressure preferably from about 15 mTorr to about 150 mTorr, at a temperature preferably from about 20°C to about 60°C, and at a power output preferably from about 100 watts to about 800 watts to deposit an outer functional layer. In this embodiment, the outer functional layer is based on C1-C3-based PFAS, while the second functional layer is based on HMDSO or DLC. Example

[0071] Example 1

[0072] A preferred embodiment of the filter medium based on the fabric according to the invention comprises a woven structure with different patterns to achieve maximum repellency, and thus obtains a superhydrophobic and oleophobic surface with a contact angle greater than 110°, as can be seen in Table 1. The degree of plasma-induced hydrophobicity and oleophobicity is also related to the textile structure and weave. Penetration of plasma material into the textile structure can achieve higher repellency. Therefore, the hydrophobicity and oleophobicity of the substrate also depend on the arrangement of both weft and warp yarns in the fabric, the fineness of the final filaments, the fabric density and weave structure, and the fiber content.

[0073] Table 1: Comparative examples of contact angles of three liquids on a polyester mesh coated with (item number 3A07-0025-158-XX)

[0074]

[0075] Example 2

[0076] The oil repellency of the treated polymer fabrics was also evaluated in parallel according to AATCC 118, a pass-or-fail method that tests for oil repellency rather than aqueous repellency. AATCC 118 uses eight liquid hydrocarbons with decreasing surface tension to determine oil repellency. The oil grades range from 0 (failure) using Kaydol (a mineral oil with a surface tension of 31.5 mN / m at 25°C) to 8 (highest oil repellency) using n-heptane (which has a surface tension of 19.8 mN / m at 25°C). The number assigned to an oil that does not wet the sample is considered the repellency oil grade.

[0077] Table 2: Comparative examples of spray and droplet tests for coated polyester mesh (item number 3A07-0025-158-XX)

[0078]

[0079] As can be seen in Table 2, similar and / or better results can be obtained using the coatings of this invention compared to the C6-based standard coatings. This finding can be explained as follows: physical modification promotes the roll-off effect. The PDMS-like coating (i.e., pp-HMDSO) enhances water repellency, and the fluorinated top coating is effective against oils, fats, and milk.

[0080] Based on this invention, polymer fabrics for filter media can be produced, wherein the hydrophobic and oleophobic groups embedded in the fabric exhibit stability and resistance to accelerated aging treatment according to ASTM F1980-16. Furthermore, the two-step hydrophobic and oleophobic nanocoating of the filter media exhibits excellent repellency to water and oil according to ISO 4920 and AATCC 118, respectively.

[0081] Based on this invention, robust and reliable fabrics with hydrophobic and oleophobic properties can be provided.

Claims

1. Polymer fabrics, including: An outer functional layer with hydrophobic and oleophobic properties, made from the first compound. A second functional layer with hydrophobic properties, made from a second compound. The first compound and the second compound are different from each other. The outer functional layer is at least partially coated with the second functional layer. The outer functional layer is a plasma nanocoating based on perfluorinated and polyfluoroalkyl substances (PFAS) containing only one, two, or three carbon atoms and / or based on perfluorinated polyether compounds (PFPE). The second functional layer is a plasma nanocoating based on a hexamethyldisiloxane (HMDSO) or diamond-like carbon (DLC) layer.

2. The polymer fabric according to claim 1, wherein the second functional layer does not have oleophobic properties.

3. The polymer fabric according to claim 1, wherein the outer functional layer and / or the second functional layer are deposited by means of a low-pressure plasma coating technique.

4. The polymer fabric of claim 1, wherein the polymer fabric comprises a weaving carrier layer woven from first and second monofilament yarns, wherein the first and second monofilament yarns are made from the same or different polymer materials.

5. The polymer fabric according to claim 1, wherein the polymer fabric comprises a composite film, the composite film comprising at least a weaving carrier layer and an electrospun film layer.

6. The polymer fabric according to claim 1, wherein the ratio of the thickness of the second functional layer to the thickness of the outer functional layer is 2:1, 3:1 or greater.

7. A method for producing the polymer fabric according to claim 1, The process involves depositing an external functional layer on the polymer fabric using low-pressure plasma coating technology, which provides hydrophobic and oleophobic properties. A second functional layer providing hydrophobic properties is deposited on the polymer fabric using low-pressure plasma coating technology, and The second functional layer is deposited on the polymer fabric before the outer functional layer is deposited on the polymer fabric.

8. The method of claim 7, wherein prior to depositing the second functional layer, the polymer fabric is pretreated using argon, helium, nitrogen, oxygen, and tetrafluoromethane gas and / or gaseous mixtures thereof by means of low-pressure plasma technology.

9. The method of claim 7, wherein the polymer fabric undergoes a two-step pretreatment before depositing the second functional layer, wherein... In the first step, the polymer fabric is coated with a UV-curable embossing resin using gravure printing and / or a slot die coating method. In the second step, surface patterning is performed using UV embossing and / or thermal embossing methods.

10. The method of claim 7, wherein the polymer fabric is pretreated prior to the deposition of the second functional layer, wherein the polymer fabric is treated with an aqueous solution containing sodium hydroxide (NaOH).

11. The method of claim 7, wherein the outer functional layer and / or the second functional layer are deposited in a process step to obtain a fluorine-doped hexamethyldisiloxane (HMDSO) plasma nanocoating and / or a fluorine-doped DLC plasma nanocoating.

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