Film and article comprising the same

Abstract

The film comprises A) a microporous polyethylene film wherein the microporous polyethylene film comprises polyethylene wherein the polyethylene has a weight average molecular weight of greater than 500,000 g / mol wherein the microporous polyethylene film has a porosity of at least 40% by volume and wherein the microporous polyethylene film has a Gurley number of less than 200 seconds; and B) a hydrophilic polymer wherein some of the hydrophilic polymer is located within at least a portion of the pores of the microporous polyethylene film, and at least some of the hydrophilic polymer forms a capping layer present on at least one surface of the microporous polyethylene film, and wherein the capping layer is substantially free of voids.

Description

Technical Field

[0001] The present invention relates to a waterproof breathable film and articles comprising the film, which can be used in a variety of applications. The film can be used alone or laminated with other layers to form a multilayer laminate. Background Art

[0002] Clothing and other types of apparel, such as shoes, gloves, and hats, often contain a waterproof, breathable layer to keep the wearer dry in wet conditions. These garments can be formed using a laminate of a breathable, waterproof layer and one or more textiles. Composite waterproof, breathable membranes made of porous PTFE membrane and hydrophilic polyurethane are currently used to make textile laminates, such as those manufactured by WL Gore & Associates, Inc. of Newark, Delaware, and PTFE membranes are commercialized under the trademark PTFE. They are microporous and generally hydrophobic, with the pores larger than a single water molecule but much smaller than a water droplet. Water vapor can pass through the material, but water droplets cannot cross from one side of the membrane to the other.

[0003] While microporous PTFE membranes work well, porous polyurethane membranes have also been developed for use in clothing. However, these membranes can lack durability and, in some cases, can be dissolved by common products such as nail polish or insect repellent spray. These membranes also have limitations, being stiff and noisy when the wearer moves.

[0004] Composite membranes composed of porous membranes (e.g., polyethylene) coated with hydrophilic polymers have also been considered, but these present several challenges. For example, due to the relatively low heat resistance of porous materials (e.g., polyethylene), it is difficult to select hydrophilic polymers or curing agents with high reaction temperatures (e.g., curing temperatures) considering their processing temperatures. Furthermore, the applied hydrophilic polymers and curing agents can react with moisture (or humidity) in the atmosphere or chemical reactions with the curing agent, generating gases that could affect the surface properties (e.g., appearance) of the coating. Summary of the Invention

[0005] Technical issues

[0006] There is a continuing need to produce films (substantially free of voids) that can impart a variety of appearances to articles (such as garments) containing the films.

[0007] Technical solutions used to solve the problem

[0008] The present disclosure relates to a first embodiment, which is a thin film comprising:

[0009] A) a microporous polyethylene film, wherein:

[0010] i) a weight average molecular weight greater than 500,000 g / mol;

[0011] ii) a porosity of at least 40% by volume;

[0012] iii) Gurley number less than 200 seconds;

[0013] B) a hydrophilic polymer, wherein at least some of the hydrophilic polymer is located within at least a portion of the pores of the microporous polyethylene membrane and at least some of the hydrophilic polymer comprises a cap layer present on at least one surface of the microporous polyethylene membrane;

[0014] The cap layer is substantially free of voids.

[0015] The present disclosure also relates to articles comprising at least one of the films.

[0016] In a second embodiment, the present disclosure is directed to the film of embodiment 1, wherein substantially all of the pores of the microporous polyethylene membrane are filled with the hydrophilic polymer.

[0017] In a third embodiment, the present disclosure is directed to the film of any one of embodiments 1 or 2, wherein the film further comprises a release layer, and the release layer is adjacent to the cover layer.

[0018] In a fourth embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 3, wherein the cap layer has a controlled surface morphology.

[0019] In a fifth embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 4, wherein the controlled surface topography comprises a surface transferred from a release layer disposed on a cover layer.

[0020] In a sixth embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 5, wherein the film has an opacity of 10 to 85.

[0021] In a seventh embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 6, wherein the film has a heat resistance of no more than 190 degrees Celsius.

[0022] In an eighth embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 7, wherein the film has a tensile strength in the MD direction of 0.45 kgf or greater.

[0023] In a ninth embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 8, wherein the tensile strength in the TD direction is 0.36 kgf or more.

[0024] In a tenth embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 9, wherein the hydrophilic polymer comprises polyurethane, polyamide, polyester, epoxy resin, silicone resin, ionomer, or a copolymer or combination thereof.

[0025] In an eleventh embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 10, wherein the film has a Gurley number of 1000 seconds or greater.

[0026] In a twelfth embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 11, wherein the surface gloss of the film is 3.0 gloss units or greater.

[0027] In a thirteenth embodiment, the present disclosure is directed to the film of any one of embodiments 1 to 12, wherein the film has an MVTR of 2500 g / m 2 / day or more.

[0028] In a fourteenth embodiment, the present disclosure is directed to an article comprising the film of any one of embodiments 1 to 13.

[0029] In some embodiments, the film comprises A) a microporous polyethylene membrane, wherein the microporous polyethylene membrane comprises polyethylene, wherein the polyethylene has a weight average molecular weight greater than 500,000 g / mol, wherein the microporous polyethylene membrane has a porosity of at least 40 volume percent, and wherein the microporous polyethylene membrane has a Gurley number less than 200 seconds; and B) a hydrophilic polymer, wherein at least some of the hydrophilic polymer is located within at least a portion of the pores of the microporous polyethylene membrane and at least some of the hydrophilic polymer forms a capping layer present on at least one surface of the microporous polyethylene membrane, and wherein the capping layer is substantially free of voids.

[0030] In some embodiments, the hydrophilic polymer in the microporous polyethylene membrane substantially fills all pores of the microporous polyethylene membrane.

[0031] In some embodiments, the film further comprises a release layer, wherein the release layer is adjacent to the cover layer.

[0032] In some embodiments, the cover layer has a controlled surface topography. In some embodiments, the controlled surface topography comprises a surface transferred from a release layer disposed on the cover layer.

[0033] In some embodiments, the film has an opacity of 10 to 85.

[0034] In some embodiments, the film has a heat resistance of no more than 190 degrees Celsius.

[0035] In some embodiments, the film has a tensile strength in the MD direction of 0.45 kgf or greater.

[0036] In some embodiments, the film has a tensile strength in the TD direction of 0.36 kgf or greater.

[0037] In some embodiments, the hydrophilic polymer comprises polyurethane, polyamide, polyester, epoxy resin, silicone resin, ionomer, or a copolymer or combination thereof.

[0038] In some embodiments, the film has a Gurley number of 1000 seconds or greater.

[0039] In some embodiments, the surface gloss of the film is 3.0 gloss units or greater.

[0040] In some embodiments, the water vapor permeability of the film is 2500 g / m 2 / day or higher.

[0041] In some embodiments, an article comprises any of the films described above.

[0042] Advantageous Effects of the Invention

[0043] The film has a substantially void-free cover layer, and the hydrophilic polymer fills at least a portion of the pores in the porous polyethylene film. This reduces diffuse reflection of light caused by the voids, thereby easily achieving a desired appearance. Furthermore, the surface morphology of the film cover layer is easily controllable. Furthermore, excellent waterproofness and breathability are easily achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A scanning electron micrograph (SEM) of a thin film including a conventional capping layer is shown, in which the capping layer contains voids and the surface becomes uneven.

[0045] Figure 2 Shown is a SEM of a capping layer according to one embodiment of the present invention, wherein the capping layer contains no voids.

[0046] Figure 3A SEM showing the relatively smooth surface morphology of the release layer.

[0047] Figure 3B The surface morphology of the cover layer after the release layer is removed is shown.

[0048] Figure 4A SEM showing the relatively rough surface morphology of the release layer.

[0049] Figure 4BThe surface morphology of the cover layer after the release layer is removed is shown.

[0050] Figure 5 SEM showing the surface morphology of the cube pattern transferred from the release layer surface. DETAILED DESCRIPTION

[0051] The disclosures of all cited patent and non-patent documents are incorporated herein by reference in their entirety.

[0052] As used herein, the terms "embodiment" or "disclosure" are not meant to be limiting, but rather apply generally to any of the embodiments defined in the claims or described herein. These terms are used interchangeably herein.

[0053] Furthermore, unless the context clearly indicates otherwise, the term "based on" is not exclusive and allows for being based on additional factors not described. Additionally, throughout this specification, the meanings of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0054] The features and advantages of the present disclosure will be more readily understood by those of ordinary skill in the art by reading the following specific embodiments. It should be understood that certain features of the present disclosure (which, for clarity, are described above or below in the text of different embodiments) may be provided in combination in a single embodiment. On the contrary, for brevity, various features of the present disclosure described as a combination in the context of a single embodiment may also be provided individually or in any sub-combination. In addition, unless the context clearly indicates otherwise, reference to the singular may also include the plural (e.g., "one" and "a" may refer to one or more / one or more).

[0055] Unless expressly stated otherwise, the use of numerical values ​​within the various ranges specified in this application is intended to be approximate, as if the minimum and maximum values ​​within the stated ranges were preceded by the word "about." In this manner, slight variations above and below the specified ranges can be used to achieve substantially the same results as the values ​​within the ranges. Furthermore, these ranges are intended to be disclosed as a continuous range, including every value between the minimum and maximum values.

[0056] As used herein, the term "membrane" refers to a polymer in the form of a substantially two-dimensional sheet, wherein both the length and width are much greater than the thickness, for example, both the length and width are at least 100 times the thickness. In some embodiments, the membrane is a microporous membrane having a structure that allows, for example, water vapor to pass through the thickness of the membrane while preventing liquid water from penetrating from one side of the membrane to the other. On average, the pore size is from a few nanometers to about one micron.

[0057] The term "film" refers to a membrane in which the pores are at least partially filled with a polymer, such that gas or liquid cannot flow through the open pore channels in the membrane. In some embodiments, the polymer that at least partially fills the pores may be a hydrophilic polymer.

[0058] The term "hydrophilic polymer" refers to a polymer that is capable of transferring large amounts of water through a film by absorbing water on one side of the film where the water concentration is higher and desorbing or evaporating the water on the other side of the film where the water vapor concentration is lower. In some embodiments, a 10 micron thick layer of a hydrophilic polymer may have a water vapor transmission rate greater than or equal to 5,000 g / m 2 / day, or greater than or equal to 10,000 g / m 2 / sky.

[0059] Throughout this specification, the phrases "microporous polyethylene film," "porous polyethylene film," and "polyethylene film" are used interchangeably. Unless otherwise expressly stated, these phrases refer to microporous polyethylene films having: i) a weight-average molecular weight greater than 500,000 g / mol; ii) a porosity of at least 40%; and iii) a Gurley number less than 200 seconds. Under magnification, the porous polyethylene film exhibits a fibrillated structure of polyethylene fibrils, and at sufficient magnification, one or more polyethylene fibrils, optionally three or more of which may be interconnected by one or more intersections of the three or more fibrils, are visible.

[0060] As used herein, the term "polyethylene" refers to a polyethylene polymer having less than 5 wt.% of one or more comonomers. In some embodiments, the polyethylene does not contain any fluorine-containing comonomers, and in other embodiments, the polyethylene is a polyethylene homopolymer.

[0061] The present disclosure relates to a film comprising A) a microporous polyethylene film, B) a hydrophilic polymer, wherein at least some of the hydrophilic polymer fills at least a portion of the pores of the porous polyethylene film, and at least some of the hydrophilic polymer is referred to as a capping layer, the capping layer being present on at least one surface of the microporous polyethylene film, and wherein the capping layer is substantially free of voids. The film will not leak due to contamination by oil, detergents, or other substances that reduce the contact angle, and is therefore waterproof. In addition, compared to other airtight hydrophilic films that do not include a porous polyethylene film as a structural support, articles comprising the film have better durability in the field and during washing. The weight average molecular weight of the porous polyethylene film may be greater than 500,000 g / mol (e.g., it may be formed from polyethylene having a weight average molecular weight greater than 500,000 g / mol (g / mol)). In some embodiments, the weight average molecular weight of the porous polyethylene film is greater than 750,000 g / mol (e.g., it may be formed from polyethylene having a weight average molecular weight greater than 750,000 g / mol (g / mol)). In yet other embodiments, the porous polyethylene membrane has a weight average molecular weight greater than 1,000,000 g / mol (e.g., it may be formed from polyethylene having a weight average molecular weight greater than 1,000,000 g / mol). In yet other embodiments, the porous polyethylene membrane has a weight average molecular weight greater than 1,500,000 g / mol or greater than 1,750,000 g / mol (e.g., it may be formed from polyethylene having a weight average molecular weight greater than 1,500,000 g / mol or greater than 1,750,000 g / mol). In yet other embodiments, the porous polyethylene membrane has a weight average molecular weight greater than 2,000,000 g / mol, 3,000,000 g / mol, 4,000,000 g / mol, 5,000,000 g / mol, or greater than 8,000,000 g / mol (e.g., it may be formed from polyethylene having a weight average molecular weight greater than 2,000,000 grams / mole (g / mol), or greater than 3,000,000 g / mol, or greater than 4,000,000 g / mol, or greater than 5,000,000 g / mol, or greater than 8,000,000 g / mol).

[0062] The microporous polyethylene film is a porous polyethylene film, wherein the porosity of the film is at least 40 volume %. In some embodiments, the porosity of the porous polyethylene film may be at least 50 volume %, or at least 60 volume %, or at least 70 volume %, or at least 80 volume %. The porosity (f) of the film can be calculated by measuring the mass per unit area (MPA) of the film and the thickness (t) of the film, and using the relationship f=(1-MPA / (t*p))*100, wherein p is the density of the film polymer. The Gurley of the porous polyethylene film can also be less than 200 seconds, or less than 100 seconds, or less than or equal to 90 seconds, or less than or equal to 80 seconds, or less than or equal to 70 seconds, or less than or equal to 60 seconds, or less than or equal to 50 seconds, or less than or equal to 40 seconds, or less than 10 seconds.

[0063] The weight of the microporous polyethylene film can be relatively light, for example less than or equal to 10 g / m 2 In other embodiments, the porous polyethylene film may have a weight of less than or equal to 9 gsm, or less than or equal to 8 gsm, or less than or equal to 7 gsm, or less than or equal to 6 gsm, or less than or equal to 5 gsm, or less than or equal to 4 gsm, or less than or equal to 3 gsm, or less than or equal to 2 gsm.

[0064] The microporous polyethylene film may be colored or colorless. The use of a porous polyethylene film can provide valuable aesthetic qualities to the film and the article containing the film, particularly when the porous polyethylene film is visible in the article. Any known coloring method can be used. For example, the entire body of the porous polyethylene film can be colored by adding a pigment or dye during the film formation process. In other embodiments, the porous polyethylene film can be colored after formation by known printing and dyeing processes. In yet other embodiments, the porous polyethylene film may be free of or substantially free of any added color, and color may be added at one or more steps during the film formation process as described herein.

[0065] The film also includes a hydrophilic polymer that fills at least a portion of the pores of the microporous polyethylene film. The phrase "filling at least a portion of the pores" refers to that the hydrophilic polymer is absorbed into the pores of the polyethylene film and fills the pores to the extent that the film region containing the hydrophilic polymer cannot be measured to have air passing therethrough (the Gurley number is greater than or equal to 1000 seconds). In other words, the hydrophilic polymer is not only a coating on the polyethylene film wall that defines the pores. Although there may be some voids, it is believed that the hydrophilic polymer forms a continuous layer in the region of the porous polyethylene film to which the hydrophilic polymer is applied. In other embodiments, the hydrophilic polymer forms a continuous layer that does not contain or is substantially free of any voids in the region of the porous polyethylene film to which the hydrophilic polymer is applied. In yet other embodiments, substantially all of the pores of the porous polyethylene film are filled with the hydrophilic polymer. The hydrophilic polymer can pass through the microporous polyethylene film along the thickness direction of the film and fill to the edge of the film.

[0066] As used in this specification, the term "substantially" or "substantially" is defined as conforming largely but not necessarily entirely to what is specified (and including what is specified), as understood by one of ordinary skill in the art, that is, within the range suitable for achieving the intended purpose or function.

[0067] For example, "substantially free of voids" may mean that the area ratio of voids in cross-sectional observation is several percent or less, such as 1% or less, 2% or less, 3% or less, 4% or less, 5% or less, 6% or less, 7% or less, 8% or less, 9% or less, or 10% or less. In addition, "substantially all pores are filled" may mean that the area ratio of unfilled portions of pores in cross-sectional observation is several percent or less, such as 1% or less, 2% or less, 3% or less, 4% or less, 5% or less, 6% or less, 7% or less, 8% or less, 9% or less, or 10% or less.

[0068] Polyethylene film has a first side and a second side. The hydrophilic polymer can be applied to the first side of porous polyethylene film, and this hydrophilic polymer can penetrate at least a portion of the pores to form the film, thereby filling at least a portion of the pores of the polyethylene film. In addition, the first side of the polyethylene film is included in the hydrophilic polymer cover layer outside the film. The hydrophilic polymer constituting the cover layer is the same hydrophilic polymer as the hydrophilic polymer in at least a portion of the pores of the polyethylene film (or filling at least a portion of the polyethylene film). However, those hydrophilic polymers are present in different positions. In addition, those hydrophilic polymers are communicated with it, for example, they are communicated with it by the first side of porous polyethylene film. The amount of the cover layer on the first side of porous polyethylene film or the hydrophilic polymer is substantially unlimited.

[0069] In some embodiments, the thickness of the cover layer of the hydrophilic polymer on the first surface of the polyethylene film can be at most 40 microns, or at most 30 microns, or at most 20 microns, or at most 15 microns. In some embodiments, the thickness of the cover layer of the hydrophilic polymer on the first surface of the polyethylene film can be at most about 10 microns. In other embodiments, the thickness of the cover layer on the first side of the polyethylene film is less than or equal to 10 microns, or less than or equal to 8 microns, or less than or equal to 6 microns, or less than or equal to 4 microns, or less than or equal to 2 microns. The second side of the polyethylene film can be substantially free of any hydrophilic polymer on the surface, for example, and the hydrophilic polymer thickness on the surface of the polyethylene film is no more than 1 micron. In some embodiments, less than the entire thickness of the porous polyethylene membrane is filled with a hydrophilic polymer. For example, less than or equal to 90% of the thickness of the polyethylene membrane may be filled with a hydrophilic polymer, provided that sufficient hydrophilic polymer is absorbed to provide the porous polyethylene membrane with a Gurley number greater than or equal to 1000 seconds. In other embodiments, substantially the entire thickness of the porous polyethylene membrane is filled with a hydrophilic polymer. As used herein, the phrase "substantially the entire thickness" means that at least 90% of the thickness of the porous polyethylene membrane is filled with the hydrophilic polymer.

[0070] In some embodiments, the hydrophilic polymer can be applied to the porous polyethylene membrane in a continuous manner such that substantially 100% of the surface area of ​​the porous polyethylene membrane comprises the hydrophilic polymer. As used herein, the term "continuously" means that the entire width or nearly the entire width of the porous polyethylene membrane is coated with the hydrophilic polymer.

[0071] It will be appreciated that in many coating processes, it may not be possible to coat the edges of a web of material because frames or dams at the edges do not allow the entire thickness of the film to be coated. In other embodiments, the hydrophilic polymer may be applied to the porous polyethylene membrane in a discontinuous manner. As used herein, the term "discontinuous" means that less than 100% of the surface area of ​​the porous polyethylene membrane is coated with the hydrophilic polymer, and a portion of the non-edge area of ​​the porous polyethylene membrane is free of the hydrophilic polymer. For example, a hydrophilic polymer applied to a porous polyethylene membrane in a series of dots or a grid of orthogonal lines is considered a discontinuous coating. The area percentage of the porous polyethylene membrane filled with the hydrophilic polymer may be in the range of greater than or equal to 20% to 100%, or 30% to less than 100%, or 40% to less than 100%, or 50% to less than 100%, or 60% to less than 100%, or 70% to less than 100%, or 80% to less than 100%, or 90% to less than 100%. In other embodiments, the application of the hydrophilic polymer can be performed in a manner that produces a random or non-random pattern of dots, polygons, parallel lines, intersecting lines, straight lines, curved lines, or any combination thereof to provide the desired coverage area percentage. If it is desired that such films have oleophobic properties, then it may be desirable in certain embodiments to include an oleophobic coating, as further described herein.

[0072] As a weight ratio, the ratio of the weight of the hydrophilic polymer (filling at least a portion of the pores of the microporous polyethylene membrane and constituting the cover layer) in the film to the weight of the porous polyethylene membrane may be in the range of 30.0 to 0.5. In other embodiments, the weight ratio of the hydrophilic polymer to the polyethylene membrane may be 20.0, 15.0, 10.0, 9.0, 8.0, 7.0, 6.0, 5.0, 4.0, 3.0, 2.0, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, or any weight ratio between these numbers.

[0073] Suitable hydrophilic polymers may include, for example, polyurethanes, polyamides, polyesters, epoxy resins, silicone resins, ionomers, or copolymers or combinations thereof. In other embodiments, virtually any suitable hydrophilic polymer may be used, provided that the hydrophilic polymer has a water vapor transmission rate greater than or equal to 5,000 g / m 2 / day, or greater than or equal to 10,000 g / m 2 / day. The hydrophilic polymer may be a thermoplastic polymer or a crosslinkable polymer. In some embodiments, the hydrophilic polymer is a polyurethane, and in other embodiments, the polyurethane is a crosslinked polyurethane. Suitable polyurethane polymers may be, for example, polyester polyurethanes, polyether polyurethanes or polyether-polyester polyurethanes. Hydrophilic polymers can be produced or obtained according to known methods. For example, the methods taught in US2020 / 013426 and JP2002-069370 (the contents of which are incorporated herein by reference in their entirety) all teach methods for obtaining existing hydrophilic polymers, and these teachings can be adjusted to obtain the hydrophilic polymers of the present disclosure.

[0074] In some embodiments where coloring is desired, a colored hydrophilic compound (wherein a pigment or dye has been added to the hydrophilic compound) can be used to add color, thereby forming a film with the desired color. In other embodiments, the porous polyethylene film can be colored during the formation of the porous polyethylene film according to known methods (such as a masterbatch method). Therefore, one or both of the porous polyethylene film and the hydrophilic film can be colored or colorless. If the porous polyethylene and the hydrophilic compound are colored, they can be dyed into the same or similar shade (shade), or colors can be selected independently of each other. Any known pigment or dye can be used, including organic pigments and dyes, inorganic pigments and dyes, metals, metal oxides, carbon black, titanium dioxide, or a combination thereof.

[0075] In some other embodiments, the porous polyethylene membrane can be treated with an oleophobic and hydrophilic polymer. For example, in a first step, the first side of the porous polyethylene membrane can be treated with an oleophobic polymer, which can coat the walls defining the pores of the porous polyethylene membrane without filling the pores, wherein the oleophobic polymer is provided so that less than the entire thickness of the porous polyethylene is treated with the oleophobic polymer. After the oleophobic polymer is subjected to an optional drying and curing step, the second side of the porous polyethylene membrane can be treated with a hydrophilic polymer to fill at least a portion of the remaining thickness of the porous polyethylene membrane, followed by an optional heating and curing step for the hydrophilic polymer and the oleophobic polymer. In these embodiments, the hydrophilic polymer only fills the portion of the porous polyethylene membrane that is not oleophobically treated, because the hydrophilic polymer cannot wet the oleophobically treated portion of the porous polyethylene membrane.

[0076] In some embodiments, the porous polyethylene film can be treated with an oleophobic polymer, the treatment being greater than or equal to 5% of the thickness of the porous polyethylene film. In other embodiments, the porous polyethylene film may include an oleophobic treatment that is less than or equal to 95% of its thickness. In some further embodiments, the oleophobic treatment may be present in the following range: 10 to 90% of the thickness of the porous polyethylene film, or 10 to 80% of the thickness of the porous polyethylene film, or 10 to 70% of the thickness of the porous polyethylene film, or 10 to 60% of the thickness of the porous polyethylene film, or 10 to 50% of the thickness of the porous polyethylene film, or 10 to 40% of the thickness of the porous polyethylene film, or 10 to 30% of the thickness of the porous polyethylene film, or 10 to 20% of the thickness of the porous polyethylene film. After treating the first side of the porous polyethylene film, the second side of the porous polyethylene film can be treated with a hydrophilic polymer, which can fill any remaining thickness of the porous polyethylene film and, in some embodiments, forms a capping layer of a hydrophilic polymer.

[0077] The cover layer is located on at least one surface of the microporous polyethylene film. Therefore, the cover layer can affect the appearance of the film. The cover layer can be formed by applying a hydrophilic polymer to at least one surface of the porous polyethylene film. Generally, the hydrophilic polymer can react with moisture in the atmosphere, etc., thereby generating gas. In addition, when a curing agent is used to cross-link the hydrophilic polymer, gas can be generated due to the reaction of the curing agent itself or the reaction between the curing agent and the hydrophilic polymer. Therefore, after the hydrophilic polymer solidifies or solidifies, gaps may remain in the cover layer. The remaining gaps in the cover layer can cause diffuse reflection of light, resulting in an uneven surface and affecting the appearance of the film. These films (or products containing them) are generally difficult to achieve the desired appearance. As described in more detail herein, the present inventors have found that a cover layer substantially free of gaps can be obtained by covering a film containing the porous polyethylene film, the hydrophilic polymer and the cover layer with a release layer adjacent to the cover layer until the hydrophilic polymer (which may include the hydrophilic polymer constituting the cover layer) solidifies or solidifies. The hydrophilic polymer filling the pores of the polyethylene film and the hydrophilic polymer constituting the cover layer are inhibited from contacting with moisture in the atmosphere by the release layer, and react with the moisture contained in those hydrophilic polymers or the moisture in contact with the opposite side of the cover layer, thereby solidifying or curing. The type, moisture content, temperature, viscosity and atmospheric moisture content and temperature of those hydrophilic polymers can be appropriately set so that the time for solidification or curing is sufficient to minimize the gas generated and / or remaining in the cover layer. The setting, especially with respect to viscosity, can be adjusted from the perspective of easily filling at least some of the gaps in the polyethylene film with the hydrophilic polymer. It is also preferred that after the hydrophilic polymer is applied to the film or forms the cover layer, the hydrophilic polymer is covered with a release layer as soon as possible to suppress contact with moisture and dust in the atmosphere. Preferably, the peeling layer does not adhere to the solidified or cured cover layer and is easy to peel off therefrom. The release layer can be commercially available.

[0078] Figure 1 : is a SEM micrograph showing the surface state (cross section) of the thin film 101 including the cover layer 102 after the gas generated by the reaction of the curing agent and the hydrophilic polymer forms voids 103 inside the cover layer 102 and solidifies or hardens. Figure 2 : is a SEM micrograph showing the surface state (cross section) of the film 201 including the cover layer 202 after the hydrophilic polymer solidifies or cures, wherein the reaction with moisture in the atmosphere is suppressed by covering it with a release layer. Figure 1 As shown, voids 103 remain in the conventional cover layer 102. Figure 2 As shown, the cover layer 202 of this embodiment has no remaining voids. Visual observation confirms that the appearance is different depending on whether there are voids in the cover layer. Figure 1 and Figure 2 The respective cover layers 102 and 202 are denoted using brackets to indicate that the respective films 101 and 201 constitute portions of the cover layers; the brackets should be understood to indicate the locations of the cover layers 102 and 202 in the figures, and not to indicate any particular thickness of the cover layers 102 and 202. Similarly, the brackets indicating the films 101 and 201 should be understood to indicate the locations of the films 101 and 201 in the figures, and not to indicate any particular thickness of the films 101 and 201.

[0079] The cap layer may have a controlled surface topography. The cap layer may have a flat surface topography because it is substantially free of voids. The flat surface topography may also be textured, embossed, or a combination thereof to produce a desired controlled surface topography. The controlled surface topography may include a desired surface roughness, desired dots, lines, or other shapes. The controlled surface topography may produce a desired appearance. In particular, a cap layer that is substantially free of voids may have less diffuse reflection of light, thereby highlighting the appearance characteristics achieved by the controlled surface topography.

[0080] The controlled surface properties can be the transfer surface of a release layer placed on the cover layer. Since the cover layer is covered by the release layer until the hydrophilic polymer (which may include the hydrophilic polymer constituting the cover layer) solidifies or solidifies, the surface topography of the solidified or solidified cover layer can serve as the transfer surface of the release layer. The surface topography of the release layer can be adjusted to achieve the desired controlled surface topography of the cover layer. Figure 3A 、 3B 4A and 4B are SEM micrographs, which respectively show the surface morphologies of the release layer and the cover layer after the release layer is removed. Figure 3A and 3B shows a relatively smooth surface morphology, while Figure 4A and 4B A relatively rough surface topography is shown.

[0081] The film's opacity can range from 10% to 85%. The film's opacity is measured using the method specified in ASTM D 2805. The cover layer is substantially free of voids, and the hydrophilic polymer fills at least a portion of the pores in the porous polyethylene film, thereby reducing diffuse reflection of light and allowing for high transparency. The opacity can be adjusted by adjusting at least one of the following: the controlled surface morphology of the cover layer, the pore-filling ratio of the hydrophilic polymer to the porous polyethylene film, the coloration of the hydrophilic polymer, and the coloration of the microporous polyethylene film. The opacity can be adjusted to 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 85, or any value in between.

[0082] The surface gloss of the film in the cover layer can be 3.0 gloss units or more. The surface gloss of the cover layer can be arbitrarily adjusted as needed for the intended use. The gloss of the sample was measured using a "Micro-TRI-μGlossμ" device from BKY at an angle of 85° on the printed surface in the cross-web direction of the sample. The recorded data is the average of three separate measurements. Since the cover layer is essentially void-free and the hydrophilic polymer fills at least some of the pores of the porous polyethylene film, the diffuse reflection of light is low and the desired gloss can be easily adjusted. The gloss can be adjusted by adjusting at least one of the following: the coloring of the hydrophilic resin, the pore filling rate of the hydrophilic polymer to the porous polyethylene film, or the controlled surface morphology of the cover layer.

[0083] In general, the molecular weight of the polymer comprising the polyethylene film of the present disclosure is reported as one or more average molecular weights (e.g., 500,000 g / mol or greater). The actual molecular weight of each polymer will be a distribution of molecular weights, and the actual molecular weight of each polymer will include a portion higher than the reported average molecular weight and a portion lower than the reported average molecular weight. In the present disclosure, the air permeability of the film (determined by water vapor transmission rate) will be affected by the heat treatment step and the polyethylene molecular weight. For example, if there is a relatively large proportion of low molecular weight polymers and the thickness of the unfilled area of ​​the polyethylene film is too large, the heat treatment step will cause deformation of the polyethylene film, such as collapse of the unfilled area, and cause the air permeability of the film to decrease or even be lost. However, if the average molecular weight of the polyethylene is significantly higher and the molecular weight distribution is small enough so that there is almost no or no low molecular weight polyethylene, then heating the film to above the melting temperature of the polyethylene will not cause the polyethylene film structure to deform or collapse, even if the polyethylene structure has not absorbed a hydrophilic polymer. Heat treatment can be carried out in an oven by placing the film on heated rollers, or by any other known heat treatment method. It should be noted that the heat treatment step that causes the mechanical properties of the film to change can be performed at any time after the polyethylene film has been coated with a hydrophilic polymer and the hydrophilic polymer (which may include a polyethylene film constituting the cover layer) has solidified. That is, the heat treatment step can be performed before or after the release layer is peeled off after the hydrophilic polymer is solidified, as long as the heat treatment temperature is within the temperature range at which the release layer does not melt or deform. In some embodiments, the polyethylene film can be coated with a hydrophilic polymer to form a film, which can then be laminated to another layer. Alternatively, in other embodiments, the film can be laminated to another layer and then coated with a hydrophilic polymer. In any embodiment, the heat treatment step can be completed after the film is made and before, during, or after the laminate is formed.

[0084] A thin film comprising a porous polyethylene membrane and a hydrophilic polymer can be produced according to the following steps:

[0085] 1) providing a porous polyethylene membrane having a weight average molecular weight greater than 500,000 g / mol, a porosity of at least 40% by volume, and a Gurley number less than 200 seconds;

[0086] 2) coating at least a portion of the porous polyethylene membrane with a hydrophilic polymer;

[0087] 3) forming a capping layer composed of a hydrophilic polymer on the side of the porous polyethylene membrane coated with the hydrophilic polymer;

[0088] 4) covering the cover layer (on the opposite side of the porous polyethylene film) with a release layer; and

[0089] 5) solidifying or curing the hydrophilic polymer.

[0090] In another embodiment, the film may be produced according to the following steps:

[0091] 1) providing a porous polyethylene membrane having a weight average molecular weight greater than 500,000 g / mol, a porosity of at least 40% by volume, and a Gurley number less than 200 seconds;

[0092] 2) coating the first side of the porous polyethylene membrane with an oleophobic polymer so as to coat the walls defining the pores of the porous polyethylene membrane;

[0093] 3) coating the second side of the porous polyethylene membrane with a hydrophilic polymer to form a thin film;

[0094] 4) forming a cover layer composed of a hydrophilic polymer on the second side of the porous polyethylene membrane;

[0095] 5) covering the cover layer (on the opposite side of the porous polyethylene film) with a release layer; and

[0096] 6) Coagulating or solidifying the hydrophilic polymer.

[0097] In another embodiment, the article may be produced according to the following steps:

[0098] 1) providing a porous polyethylene membrane having a weight average molecular weight greater than 500,000 g / mol, a porosity of at least 40% by volume, and a Gurley number less than 200 seconds;

[0099] 2) coating at least a portion of the porous polyethylene membrane with a hydrophilic polymer to form a thin film;

[0100] 3) forming a capping layer composed of a hydrophilic polymer on the side of the porous polyethylene membrane coated with the hydrophilic polymer;

[0101] 4) covering the cover layer (on the opposite side of the porous polyethylene film) with a release layer;

[0102] 5) solidifying or curing the hydrophilic polymer; and

[0103] 6) Laminating the film to at least one other layer.

[0104] In another embodiment, the article may be produced according to the following steps:

[0105] 1) providing a porous polyethylene membrane having a weight average molecular weight greater than 500,000 g / mol, a porosity of at least 40% by volume, and a Gurley number less than 200 seconds;

[0106] 2) laminating at least one other layer to the first side of the porous polyethylene membrane;

[0107] 3) coating at least a portion of the second side of the porous polyethylene membrane with a hydrophilic polymer;

[0108] 4) forming a cover layer composed of a hydrophilic polymer on the second side of the porous polyethylene membrane;

[0109] 5) covering the cover layer (on the opposite side of the porous polyethylene film) with a release layer;

[0110] 6) allowing the hydrophilic polymer to solidify or cure.

[0111] Optionally, any of the above methods may include the following processing embodiments. A hydrophilic polymer (such as polyurethane, etc.) can be layered on a porous polyethylene film at room temperature, and the composite material can be placed at room temperature, wherein there is enough moisture in the atmosphere. For layering (layering), any process, such as a coating method, can be used. As long as the hydrophilic polymer can be cured, the process can be carried out at room temperature, at a lower or higher temperature, thereby preparing a composite material. If necessary, a release layer can be superimposed on the coated side of the composite material. The composite material can be under temperature (cool-room temperature-high temperature) and a certain level of humidity conditions, which can be adjusted so that the hydrophilic polymer in the composite material is cured. As described in US2021317276 AA, the thickness of the cover layer is adjusted with the amount of the hydrophilic polymer applied.

[0112] The water vapor transmission rate (MVTR) of the obtained film including the porous polyethylene film, the hydrophilic polymer filling the pores of the film and constituting the cover layer can be greater than or equal to 2500 g / m2 / day (g / m2 / day). 2 / day); weight can be less than 30g / m 2 , and optionally the Gurley value may be greater than or equal to 1000 seconds. In order to be breathable (i.e., water vapor can be transferred from one side of the film to the other side, but liquid water will not pass through the film), the MVTR should be greater than or equal to 2500 g / m 2In other embodiments, the MVTR of the film may be greater than or equal to 3000 g / m 2 / day, greater than or equal to 3500g / m 2 / day, greater than or equal to 4000g / m 2 / day, greater than or equal to 4500g / m 2 / day, greater than or equal to 5000g / m 2 / day, greater than or equal to 5500g / m 2 / day, greater than or equal to 6000g / m 2 / day, greater than or equal to 6500g / m 2 / day, greater than or equal to 7000g / m 2 / day, greater than or equal to 7500g / m 2 / day, greater than or equal to 8000g / m 2 / day, greater than or equal to 8500g / m 2 / day, greater than or equal to 9000g / m 2 / day, greater than or equal to 9500g / m 2 / day, or greater than or equal to 10,000 g / m 2 / sky.

[0113] The film can also have a ratio of the tensile strength of the matrix in two orthogonal directions, and its scope is 0.5 to 2.0. In other embodiments, the ratio of the tensile strength in two orthogonal directions can be in the scope of 0.7 to 1.4. In other embodiments, the ratio of the tensile strength can be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 or any value between two numerals. The difference of the tensile strength in two orthogonal directions is due to the film manufacturing process, and the difference of the total strain applied on the two directions causes to a great extent.

[0114] The film may have a heat resistance of 190°C or less. In other embodiments, the heat resistance may be 180°C or less, 170°C or less, 160°C or less, 150°C or less, 140°C or less, 130°C or less, or 120°C or less. Heat resistance here means that the material exhibits minimal deformation due to thermal contraction or expansion when held at a certain temperature for 60 seconds. For example, the area change may be within 5%, 10%, 15%, or 20%.

[0115] The film may have a tensile strength in the MD direction (machine direction) of 0.45 kgf or greater. In other embodiments, the tensile strength may be 0.50 kgf or greater, 0.54 kgf or greater, 0.59 kgf or greater, or 0.63 kgf or greater.

[0116] The film may have a tensile strength in the TD direction (transverse direction) of 0.36 kgf or greater. In other embodiments, the tensile strength may be 0.41 kgf or greater, 0.45 kgf or greater, 0.50 kgf or greater, or 0.54 kgf or greater.

[0117] The film also exhibits contamination resistance because the presence of the hydrophilic polymer fills voids within at least a portion of the film thickness, thereby forming a continuous layer free of voids in that portion of the porous polyethylene film. Furthermore, the cap layer enhances the film's contamination resistance. As used herein, contamination resistance refers to the film's resistance to contamination by sweat, sebum, or grease, thereby preventing the film from losing water resistance over time. If at least a portion of the pores of the porous polyethylene film are unfilled, the oleophobic coating on the walls of the unfilled pores can provide contamination resistance to the unfilled pores.

[0118] The present disclosure also relates to articles comprising the films. One advantage of articles comprising the films of the present disclosure is that they are easier to achieve a desired appearance and exhibit less diffuse light reflection than films comprising a cover layer having voids. If the film is in the form of a laminate, a laminate comprising: a cover layer substantially free of voids; and a hydrophilic polymer that fills at least a portion of the voids in the microporous polyethylene film can more easily achieve a variety of desired appearances, compared to film laminates comprising a cover layer having voids. In certain embodiments, other components of the laminate may also contribute to a variety of appearances.

[0119] The article can be a laminate, for example, one or more film layers and one or more other layers are laminated together to form a laminate. The one or more other layers can be a fabric layer, a polymer layer, a natural leather layer, a synthetic leather layer, a fleece layer or a combination thereof. In some embodiments, the article can be a 2-layer laminate, comprising a fabric layer adhered to the first side or the second side of the film. In some embodiments, the article can be a 3-layer laminate, comprising a first fabric layer adhered to the first side of the film and a second fabric layer adhered to the second side of the film. In some other embodiments, an additional layer can be applied to obtain a laminate with 4, 5, 6 or more layers. Suitable fabric layers can include any woven, textile or non-woven textile. The textile can be natural and / or synthetic textiles, such as cotton, wool, silk, jute, polyamide, polyester, acrylic, aramid, viscose, rayon, carbon fiber or a combination thereof. Suitable polymer layers can include, for example, polyolefins, polyesters, polyamides, polyurethanes, polyvinyl alcohols, polyvinyl acetates, fluoropolymers, polyvinyl halides, polyvinyl chlorides, epoxy resins, silicone polymers, or combinations thereof. Laminates comprising one or more disclosed film layers, one or more fabric layers, and / or one or more polymer layers can also be produced.

[0120] Because the disclosed films have high strength, any of the relatively low mass textiles or materials listed above can be used to prepare laminates. In some embodiments, the laminate may include relatively low mass textiles having a basis weight of 5 g / m 2 Up to 30g / m 2 In other embodiments, the mass of the textile can be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 gsm, or any value therebetween. While relatively low mass textiles can be used, textiles weighing 30 gsm or more can also be used. For example, relatively high mass textiles weighing up to 500 gsm can be used.

[0121] Lamination technology is well known in the art, and can comprise for example, adhesive lamination and thermal bonding etc.In some embodiments, lamination is realized by adhesive lamination, wherein adhesive is applied to one or more layers to be connected together, these layers are placed together subsequently, optionally with heating and / or pressurization, for example, by nip roller (nip roller).Adhesive can be applied to film layer, fabric layer or described film layer and described fabric layer on both.Adhesive can be applied in a discontinuous manner, for example a series of adhesive points, shapes, lines or its combination.In other embodiments, adhesive can be applied as the continuous layer of adhesive.In certain embodiments, adhesive composition can be thermoplastic or crosslinking adhesive.In another embodiment, hydrophilic polymer can be used as adhesive material for forming laminate.For example, after hydrophilic polymer is applied to a side of porous polyethylene film and forms the cover layer of hydrophilic polymer, textile can be applied to hydrophilic polymer and laminate is applied to heat and / or pressure, to ensure that hydrophilic polymer fully contacts and adheres to textile. If a hydrophilic polymer is used as the binder for the laminate, the step of curing the hydrophilic polymer can be performed after the textile or other material is placed on the side of the film containing the hydrophilic polymer cover layer. In some embodiments, a hot press can be used to provide sufficient pressure to cause the hydrophilic polymer to flow into the spaces between the plant fibers, and the heat from the hot press can perform the required curing and heat treatment steps to form the laminate. In other embodiments, one or more rollers can provide the necessary pressure and / or heat to accomplish the same task, for example in a continuous manner. In other embodiments, the step of curing the hydrophilic polymer can be performed by curing or hardening the hydrophilic polymer with moisture after the textile or other material is placed on the side of the film containing the hydrophilic polymer cover layer.

[0122] Laminates with stretch and recovery properties can be produced according to known methods. For example, methods such as those taught in US 4443511, US 9950504, US 9126390, US 9233520, US 9238344, and WO 2018 / 67529 (the contents of which are incorporated herein by reference in their entirety) all teach methods for imparting stretchability to existing films and laminate structures, and these teachings may be applicable to providing stretchability to laminates comprising the films of the present disclosure.

[0123] The article can be, for example, a garment, a shell, a protective shell, a tent, a sleeping bag, a bivy bag, a backpack, a package, a covering, and other similar forms that benefit from the properties of the films disclosed herein. The garment can be a jacket, a coat, a shirt, a pair of pants, a glove, a hat, a shoe, a coverall, or at least a portion thereof. Many articles are finished products formed by sewing or otherwise bonding multiple panels together. Thus, "at least a portion" of an article means that at least one panel or portion of a panel comprises the disclosed film.

[0124] Articles and garments can be manufactured such that the film is located on the outside of the garment, on the inside of the garment, or wherein the film is at least one of the intermediate layers of the garment, such as the intermediate layer of a three-layer laminate. One advantage of articles and garments comprising the disclosed film is that a variety of appearances can be easily achieved. Another advantage of the articles and garments is that they can be waterproof and breathable. If the article is required to be waterproof or liquid-proof, the stitch holes can be made liquid-proof by sealing the stitch holes (e.g., with seam tape). The seam tape can be adhered to the article from either the outside or the inside.

[0125] For embodiments in which the film is positioned outside the garment (meaning it is the outermost portion of the garment), the film may be colored, colorless, textured, embossed, or any combination thereof, to produce the desired appearance. Specifically, the film has a cover layer that is substantially free of voids, and a hydrophilic polymer fills at least some of the pores of the porous polyethylene film, which reduces diffuse reflection of light and is therefore easy to obtain the desired appearance. This paper describes a method for coloring the film. In order to emboss the film, the film may be optionally compressed in a random manner or in a non-random manner, for example, a pattern, letter, word, picture, sports team logo, commercial logo, or a combination thereof may be embossed on the film or film before, after, or simultaneously with the hydrophilic polymer treatment. Selective compression can cause the translucent areas of the film to be different, which can also change the air permeability of the film, with the air permeability of the embossed area being lower than that of the non-embossed area. Suitable embossing methods are found in US20080143012, the contents of which are incorporated herein by reference as a whole.

[0126] For embodiments in which those films are positioned outside clothing (meaning it is the outermost portion of clothing), at least a portion of the film can be textured. Film texture can be made by treating the film with a random or non-random pattern of a wear-resistant polymer. A wear-resistant polymer can be applied in a series of points, lines or other shapes to provide the desired appearance and provide improved wear resistance for the outermost portion of clothing. Specifically, the film has a cover layer that is substantially free of voids, and a hydrophilic polymer fills at least some of the pores of the porous polyethylene film, which reduces diffuse reflection of light and is therefore easy to obtain the desired appearance. Suitable wear-resistant polymers and methods for applying them are found in US2010 / 0071115, the contents of which are incorporated herein by reference as a whole. Another method for texturing a film can include applying flock to at least a portion of the film. Suitable methods for applying flock material are found in WO 99 / 39038, the contents of which are incorporated herein by reference as a whole.

[0127] It has also been discovered that films and articles (e.g., laminates comprising the films) can be provided with substantially permanent creases without the use of additional chemicals currently used. This is particularly useful in garments, such as pants, comprising the films and at least one fabric layer. It has been discovered that when a laminate comprising a film and a textile is placed in an embroidery hoop and heated and then cooled, a crease will appear in the portion of the laminate that was secured in the hoop when it is removed from the hoop. The heating temperature should be greater than or equal to 125°C, or greater than or equal to 130°C and less than or equal to 190°C. In embodiments where creases are desired, such as in garments, the creases can be produced by folding the article and pressing with heat.

[0128] Example

[0129] The following examples are provided to illustrate the embodiments of the present invention. These examples do not limit the scope of the present invention.

[0130] Test Method

[0131] Molecular weight

[0132] Molecular weight determinations were performed according to the procedure given in Mead, DW, "Determination of Molecular Weight Distributions of Linear Flexible Polymers from Linear Viscoelastic Material Functions," Journal of Rheology, 1994, 38(6): 1797-1827.

[0133] Porosity

[0134] Porosity is expressed as percent porosity and is determined by subtracting the quotient of the average density of the porous polyethylene film and the true density of the polymer from 1 and multiplying this value by 100. For calculation purposes, the true density of polyethylene is taken to be 0.94 g / cm 3 The density of a sample is calculated by dividing the mass / area of ​​the sample by its thickness.

[0135] Water Vapor Permeability Test Solution

[0136] MVTR was tested according to DIN EN ISO 15496 (2004). As this is a standard test used in the textile industry, reference is made to the detailed description of the MVTR test disclosed in DIN EN ISO 15496 (2004). For a description of the MVTR test, reference is also made to WO 90 / 04175 A1.

[0137] The basic principle can be summarized as follows. The sample to be tested is inserted into a ring-shaped sample holder together with a microporous membrane that is highly water vapor permeable but waterproof. Subsequently, the holder is immersed in water for 15 minutes (deionized water at 23°C) to bring the membrane into contact with the water. The cup is filled with a saturated aqueous solution of potassium acetate to produce a relative humidity of 23% on the surface of the sample and covered with a second identical waterproof microporous membrane. The cup containing the potassium acetate solution and the second membrane is weighed and placed on top of the sample holder so that the second membrane is in contact with the sample. This causes water vapor to transfer from the water side through the sample to the cup containing potassium acetate. After 15 minutes, the cup containing potassium acetate is removed and its weight is measured. The same procedure is carried out on the first and second membranes, but without the sample, to determine the water vapor permeability of the test device without the sample. Subsequently, the MVTR of the sample can be determined from the difference between the two measurements, taking into account the influence of the two additional microporous membranes.

[0138] The water vapor transmission rate (MVTR) of the laminate according to the invention is measured according to EN ISO 15496 (2004) and is expressed in g / m 2 / 24h. In order to be considered water vapor permeable as used herein, the laminate should generally have a water vapor permeability of at least 3000 g / m 2 / 24h water vapor permeability, preferably at least 8000g / m 2 / 24h, more preferably at least 12000g / m 2 / 24h. MVTR value can be as high as 20000g / m 2 / 24h.

[0139] Gurley

[0140] The Gurley air flow test measures the air flow at 100 cm under 12.4 cm of water pressure.3 Air flows through 6.45cm 2 The time required for the sample to pass (in seconds) was measured using a Gurley Densometer Model 4110 Automatic Densometer equipped with a Gurley Model 4320 Automatic Digital Timer. The reported results are the average of multiple measurements.

[0141] Matrix tensile strength (MTS)

[0142] To determine MTS, the sample film was cut in the longitudinal and transverse directions using ASTM D412-Dog Bone Die Type F. A flat-faced grip and a 90.72 kg load cell were used. The tensile breaking load was measured using a 5500R (Illinois Tool Works Inc., Norwood, MA) tensile testing machine. The gauge length of the clamp was set to 8.26 cm, and a strain rate of 0.847 cm / s or 14.3% / s was used. After the sample was placed in the clamp, the sample was retracted 1.27 cm to obtain a baseline, and then the tensile test was performed at the above strain rate. Two samples were tested for each condition, and the average of the maximum load (i.e., peak force) measurements was used for the MTS calculation. The longitudinal and transverse MTS were calculated using the following formula:

[0143] MTS = (maximum load / cross-sectional area)*(true density of polymer / density of membrane).

[0144] Thickness measurement

[0145] The thickness of the film was measured by placing it between the two plates of a Kafer FZ1000 / 30 thickness caliper (Kafer Messuhrenfabrik GmbH FI, Villingen-Schwenningen, Germany). The average of three measurements was used.

[0146] Mass per unit area (g / m 2 count)

[0147] The mass per unit area of ​​the sample (mass / area) is calculated by measuring the mass of a well-defined area of ​​the sample using a scale. The sample is cut into a defined area using a die or any precision cutting instrument.

[0148] Color Analysis

[0149] The tristimulus values ​​of the film samples were measured using a spectrophotometer Color i5 (X-Rite Incorporated, Grand Rapids, Michigan), which are expressed as XYZ in the CIE 1931XYZ color space and as L*a*b* in the CIELAB color space. The aperture size was set to 8 mm. The color measurement was performed with white and black as the background colors behind the film. The resulting stimulus values ​​are X, Y, and Z for white and X, Y, and Z for black, respectively. For the CIELAB color space, the resulting values ​​are L*, a*, and b* for black and L*, a*, and b* for white. A calibration plate was used for the white background, and a black trap was used for calibration of the black background. In the XYZ stimulus values, the Y stimulus value represents the light transmittance. The opacity Op (%) of the film is obtained by the following formula.

[0150] Op(%)=(Y 黑色 / Y 白色 )×100

[0151] Glossiness

[0152] Gloss measurements of the polymer coating surface were performed using a BYK "Micro-TRI-Glossμ" device at an angle of 85° in the transverse direction of the sample. The reported data are the average of 3 individual measurements.

[0153] Heat resistance test

[0154] To evaluate the heat resistance of the film, three films were cut into 150 mm squares. A 100 mm square was printed on the film surface with heat-resistant ink. The sample was hung tension-free in a convection oven [ST-120, ESPEC CORP., Osaka] and heated at a set temperature for 30 seconds. After heating, the sample was removed from the oven and, after cooling, the lengths of the four sides of the square were measured. The average value L of the lengths of each side after heating was calculated. MD2 、L TD2 (mm) relative to the initial length L before heating MD1 、L TD1 (mm) Calculate the dimensional change rate D of the sample LMD 、D LTD (%) and area change rate D 面积 The dimensional change rate and area change rate were calculated using the following formulas.

[0155] D LMD (%)=(L MD2 -L MD1 ) / L MD1 ×100

[0156] D LTD (%)=(L TD2 –L TD1 ) / L TD1 ×100

[0157] D 面积 (%)=((L MD2 ×L TD2 )-(L MD1 ×L TD1 )) / (L MD1 ×L TD1 )×100

[0158] Washing treatment

[0159] A single cycle of laminating fabric samples cut into 350 mm squares was performed using a commercially available automatic washing machine ("NA-F70PB2" manufactured by Panasonic Corporation) with a synthetic laminating detergent ("Attack Bio EX" manufactured by Kao Corporation), followed by drying at room temperature. This cycle was repeated five times. Washing was performed using 40 liters of tap water and 24 grams of detergent for 6 minutes, followed by rinsing twice and draining for 5 minutes.

[0160] Water permeability test

[0161] The water permeability test was conducted using a waterproof test apparatus ("Schopper type water permeability tester" (WR-1600M, DAIEI KAGAKU SEIKI MFG. CO., LTD., Tokyo) described in the low water pressure method in JIS L 1092. A water pressure of 9.8 kPa was applied to the laminated sample from the fabric side for 1 minute, and then when water appeared on the surface of the fabric on the side opposite to the side to which the water pressure was applied, the waterproofness was judged to be unsatisfactory, while when no water was observed, the waterproofness was considered to be satisfactory.

[0162] SEM

[0163] The surface of the polymer coating film was observed using an electron microscope at a magnification of 200 times, and the cross section of the polymer coating film was observed at a magnification of 2000 times. As the electron microscope, a "Scanning Electron Microscope S-3000H" available from Hitachi High-Tech Corporation was used.

[0164] Example 1

[0165] (Polyethylene film)

[0166] A 30 μm thick polyethylene film with a weight average molecular weight of 769,000 g / mol (available from Gelon LIB Co., Ltd., China) was stretched at 1.5:1 in MD and then at 5:1 in TD. The resulting polyethylene film had a mass of 4.1 g / m 2 , thickness is 13.9 microns, Gurley is 32.7 seconds and porosity is 69%.

[0167] (Hydrophilic polymer)

[0168] The hydrophilic polymer B was prepared according to the teaching of US Pat. No. 6,720,401 (equivalent to JP 4788020 B2) to provide a prepolymer containing isocyanate groups.

[0169] (Release liner)

[0170] The LDPE release liner is a 40-micron "Pearskin finish Natural" liner supplied by Hayashikazuji Co., Ltd. It has a thickness of 40 microns and a pearskin finish on one side and a smooth finish on the other.

[0171] (Composite Film)

[0172] The polyethylene film was printed by gravure printing (cell volume 20 cm 3 / m 2 , surface coverage of 70%, 100 lines / inch) was coated with the above-mentioned prepolymer B at a printing speed of 10 m / min at 25 degrees Celsius. The coating amount of prepolymer B was 10 g / m 2 . After prepolymer B was printed on the porous polyethylene film, the release liner was immediately covered on the printed surface, passed through a roller and fully pressed. During this process, the smooth surface side of the release liner faced the coating side of the film. By diffusing and penetrating the prepolymer B into the porous polyethylene film, the composite film changed from a turbid appearance to a translucent appearance. The resulting product (i.e., the composite film) was placed at room temperature for 12 hours (temperature: 25 degrees Celsius, relative humidity: 70%) to cure the prepolymer B by reacting with moisture in the air. After the curing was completed, the release liner was removed from the composite film to obtain a polyethylene film coated with hydrophilic polyurethane "Film of Example 1". The mass, thickness, Gurley and moisture permeability per unit area were measured. The results are shown in Table 1.

[0173] Example 2

[0174] (Composite Film) The film of Example 2 was obtained by a film manufacturing process carried out under the same processing conditions as in Example 1, except that the coating amount of prepolymer B was 15 g / m 2 , using different gravure printing patterns (cell volume is 30cm 3 / m 2 , 70% surface coverage, 100 lines / inch) and the pear-skin side of the release liner was overlaid on the printed side of the film.

[0175] The test results of Example 2 are shown in Table 1.

[0176] Example 3

[0177] (Polyethylene film)

[0178] A 30 μm thick polyethylene film with a weight average molecular weight of 769,000 g / mol (available from Gelon LIB Co., Ltd., China) was stretched at 2.25:1 in MD and then at 9:1 in TD. The resulting polyethylene film had a mass of 2.1 g / m 2 , thickness is 10.0 microns, Gurley is 8.7 seconds and porosity is 78%.

[0179] (Composite Film)

[0180] The film of Example 3 was obtained by the film manufacturing process under the same processing conditions as Example 1, except that 2.1 g / m 2 The above polyethylene film of Example 3 was used as a composite, prepolymer B was printed on the pear skin side of the release liner, and the release liner printed with prepolymer B was laminated to the polyethylene film. The test results of the film of Example 3 are shown in Table 1.

[0181] Example 4

[0182] (Silver hydrophilic prepolymer)

[0183] A silver hydrophilic prepolymer (prepolymer SV) was obtained by mixing 150 g of MCF#1000 carbon black (Mitsubishi Chemical Corporation, Tokyo), 670 g of EMR-DZ510 (Toyo Aluminum KK, large plate), and 9,180 g of prepolymer B using a kneading mixer. The prepolymer SV had an isocyanate group content of 6.8% by weight and a viscosity of 18,000 mPa·s.

[0184] (Composite Film)

[0185] The film of Example 4 was obtained by a film manufacturing process carried out under the same processing conditions as in Example 1, except that prepolymer SV was applied instead of prepolymer B, and a different gravure printing pattern (cell volume of 30 cm 3 / m 2 , surface coverage is 70%, 100 lines / inch), the coating amount of prepolymer SV is 15g / m 2 .

[0186] The test results of the film of Example 4 are shown in Table 1.

[0187] Example 5

[0188] (Release liner)

[0189] A release liner made of polyethylene film laminated paper, Asahi release "cube-2M" (Asahi Roll Co., Ltd., Tokyo), was used. The total thickness of the release liner was 150 μm. The release liner had a unique embossed geometric pattern on the polyethylene film laminated side of the release liner.

[0190] (Composite Film)

[0191] The film of Example 5 was obtained from a film manufacturing process conducted under the same processing conditions as Example 1, except that an Asahi peeling "cube-2M" release liner was applied to the laminate on the prepolymer print side instead of the release liner described in Example 1.

[0192] The test results of Example 5 are shown in Table 1.

[0193] Example 6

[0194] (Black hydrophilic prepolymer)

[0195] A black hydrophilic prepolymer (prepolymer BK) was obtained by mixing 150 g of MCF#1000 carbon black (Mitsubishi Chemical Corporation, Tokyo) and 9850 g of prepolymer B with a kneading mixer. The prepolymer BK had an isocyanate group content of 7.0% by weight and a viscosity of 15,000 mPa·s.

[0196] (Composite Film)

[0197] The composite film of Example 6 was obtained by a film manufacturing process carried out under the same processing conditions as in Example 1, except that prepolymer BK was applied instead of prepolymer B, and the 2.1 g / m 2The test results of Example 6 are shown in Table 1.

[0198] Example 7

[0199] (Hydrophilic prepolymer)

[0200] HYPOL TM JT6005 [The Dow Chemical Company, Midland, MI] prepolymer is a TDI-based polyurethane prepolymer with an isocyanate group content of 3.0 wt % and a viscosity of 12,000 mPa·s.

[0201] (Composite Film)

[0202] The film of Example 7 was obtained by the film manufacturing process under the same processing conditions as Example 1, except that HYPOL TM JT6005 replaces prepolymer B.

[0203] The test results of Example 7 are shown in Table 1.

[0204] Comparative Example 8

[0205] [Preparation of hexamethylenediamine carbamate (HMDC) paste]

[0206] Hexamethylenediamine carbamate (HMDC) paste was prepared according to the teaching of US 5,209,969 by the following procedure.

[0207] At 45°C and atmospheric pressure, 100 parts by mass of hexamethylenediamine (HMD) was added to 244 parts by mass of ethylene oxide / propylene oxide glycol having a hydroxyl number of 110, and the resulting mixture was sparged with CO2 to form a paste having a solids content of 35% by mass. The reduction in the amount of separated free HMD was monitored by titration until the HMD in the paste was converted to HMD carbamate. The reaction was terminated as soon as the free HMD disappeared.

[0208] (Mixture of HMDC paste and prepolymer B)

[0209] 91 parts by mass of the prepolymer B and 9 parts of the HMDC paste were mixed with a kneading mixer to obtain a "coating mixture A".

[0210] (Coating and curing process)

[0211] The "coating mixture A" was heated to 50 degrees Celsius and coated on one side of the polyethylene film surface described in Example 1 using a roll coater at 10 m / min. The coating amount was controlled at 10 g / m 2The polyethylene film coated with coating mixture A was cut into 30 cm squares, and the four sides of the squares were stapled to fix the shape. The film was then placed in a convection oven adjusted to 180 degrees Celsius for 1 minute to activate the reaction between prepolymer B and HMD by deblocking CO2 from the diamine. However, the polyethylene film coated with coating mixture A immediately melted in the convection oven, and no coating film was obtained.

[0212] Comparative Example 9

[0213] The polyethylene film coated with the coating mixture A described in Comparative Example 8 was cut into 30 cm squares, and the four sides of the squares were stapled to fix the shape. The film was then placed in a convection oven adjusted to 145°C for 30 minutes to activate the reaction between prepolymer B and HMD by deblocking CO₂ from the diamine. The coating mixture A solidified after the heating process and was placed in a constant temperature and humidity chamber at 25°C and 70% RH for 12 hours to completely cure the coating mixture A, thereby obtaining the film of Comparative Example 9.

[0214] The test results of the film of Comparative Example 9 are shown in Table 1.

[0215] Comparative Example 10

[0216] [Expanded polytetrafluoroethylene membrane (ePTFE)]

[0217] An ePTFE membrane (WL Gore & Associates, Inc., Newark, Delaware) was prepared with a membrane mass of 20 g / m 2 , thickness is 40 microns, Gurley value is 6 seconds, and porosity is 80%.

[0218] (Coating and curing process)

[0219] The "coating mixture A" described in Comparative Example 8 was heated to 50 degrees Celsius and coated on one side of the ePTFE membrane surface using a roll coater at a speed of 10 m / min. The coating amount was controlled at 10 g / m 2 The ePTFE membrane coated with coating mixture A was cut into 30 cm squares, and the four sides of the squares were stapled to secure the shape. The membrane was then placed in a convection oven set at 180°C for 1 minute to activate the reaction between prepolymer B and HMD by deblocking the CO₂ from the diamine. Coating mixture A solidified after the heating process and was placed in a constant temperature and humidity chamber at 25°C and 70% RH for 12 hours to fully cure coating mixture A, thereby obtaining the film of Comparative Example 10.

[0220] The test results of the film of Comparative Example 10 are shown in Table 1.

[0221] Comparative Example 11

[0222] The polyethylene microporous membrane described in Example 1 was tested as the film of Comparative Example 11 without any additional treatment.

[0223] The test results of the film of Comparative Example 11 are shown in Table 1.

[0224] Comparative Example 12

[0225] (Mixture of HDMC paste and prepolymer BK)

[0226] 9 parts of the HMDC paste described in Comparative Example 8 and 91 parts by mass of the prepolymer BK described in Example 6 were mixed by a kneading mixer to obtain a "coating mixture B".

[0227] (Coating and curing process)

[0228] The "coating mixture B" was heated to 50 degrees Celsius and coated on one side of the polyethylene film surface described in Example 3 using a roll coater at 10 m / min. The coating amount was controlled at 10 g / m 2 The polyethylene film coated with coating mixture B was cut into 30 cm squares and fixed on all four sides. The film was then placed in a convection oven set at 145°C for 1 minute to activate the reaction between prepolymers BK and HMD by deblocking CO₂ from the diamine. Coating mixture B solidified after the heating process and was placed in a constant temperature and humidity chamber at 25°C and 70% RH for 12 hours to fully cure. This yielded the film of Comparative Example 12.

[0229] The test results of the film of Comparative Example 12 are shown in Table 1.

[0230] Comparative Example 13

[0231] The prepolymer B prepared in Example 1 was coated on the smooth side of the release liner surface described in Example 1 using a Mayor rod at 25 degrees Celsius. The coating amount at this time was 60 g / m 2 After moisture curing in an environment of 25 degrees Celsius and 70% RH for 12 hours, the film was peeled off from the release liner to form a film consisting only of the hydrophilic polymer, which was designated as the film of Comparative Example 13. The thickness of the film was about 70 μm.

[0232] Test results at film level

[0233] As summarized in Table 1, the films obtained from Examples 1-7 and Comparative Examples 9 and 12 exhibited excellent lightness, air impermeability, and moisture permeability. The film of Comparative Example 10 was relatively thicker and heavier than the other examples. The film of Comparative Example 11, which did not have a hydrophilic polymer coating, exhibited air permeability comparable to that of a porous film.

[0234] Table 1

[0235]

[0236] Cross-section observation by SEM

[0237] Cross-sections of the films obtained in Examples 1-7 and Comparative Examples 9, 10, and 12 were observed using a scanning electron microscope. At a magnification of 2,000x, the pores of the microporous membrane in all films, except Comparative Example 10, were filled with a hydrophilic polymer. In Examples 1-7, the hydrophilic polymer on the coating surface (referred to as the cap layer) contained no voids. In contrast, the cap layers in Comparative Examples 9, 10, and 12 contained voids.

[0238] Table 2

[0239]

[0240]

[0241] Opacity / Glossiness

[0242] The surfaces on the polymer coating side of the films of Examples 1 and 3 had a slightly glossy appearance and were highly transparent. In contrast to Examples 1 and 3, the surface on the polymer coating side of the film of Example 2 had a matte finish. On the other hand, this film had high transparency similar to that of Examples 1 and 3.

[0243] The film of Comparative Example 9 had a whitish overall appearance and was less transparent than the film of Example 1. In addition, the surface on the polymer coating side had a matte appearance.

[0244] The film of Comparative Example 10 had an opaque white appearance, and the polymer coating had a matte surface.

[0245] The film of Comparative Example 11 had an opaque white appearance, which was the same as the film of Comparative Example 10. On the other hand, the surface had a glossy appearance compared with the other examples.

[0246] Table 2 shows the photometric measurement results as well as the opacity measurement results.

[0247] In Examples 1, 2, and 3, the appearance was transparent, and the color of the object inside was not significantly affected even when looking through the film. On the other hand, in the film of Comparative Example 9, the color of the object inside the film tended to become turbid. In the films of Comparative Examples 10 and 11, the color of the object inside the film was difficult to see due to its high opacity.

[0248] Visual appearance of the film

[0249] The film of Example 4 exhibited metallic luster and opacity due to the aluminum pigment on the polymer coating side surface. The opacity of the film was measured to be 75%.

[0250] The film of Example 5 exhibited a unique appearance, with the pattern of the release liner transferred to the surface of the cover layer on the polymer coating side and replicating the regular cubic pattern. Figure 5 Micrographs of thin film cube patterns are shown.

[0251] Example 6 exhibits a coal-black color due to the hydrophilic polymer coating layer mixed with carbon pigments. On the other hand, despite using the same carbon-containing polymer as Example 6, Comparative Example 12 exhibits a dark gray color on the hydrophilic polymer coating side. The difference in film appearance between Example 6 and Comparative Example 12 is believed to be due to the fact that voids in the cap layer of the film of Comparative Example 12 diffusely reflect light, thereby increasing the dark gray color.

[0252] Tensile test results

[0253] The films obtained in Example 1, Example 3, and Comparative Example 13 were subjected to tensile testing based on ASTM D412. The film of Example 1 had average maximum load values ​​of 0.98 kgf in MD and 0.63 kgf in TD, respectively. The film of Example 3 had average maximum load values ​​of 0.60 kgf in MD and 0.50 kgf in TD, respectively. Meanwhile, the film of Comparative Example 13 had average maximum load values ​​of only 0.09 kgf in both directions.

[0254] Heat resistance test results

[0255] In the heat resistance test described above, the films obtained in Examples 1 and 3 and Comparative Example 11 were heat-treated at set temperatures of 150°C and 170°C for 30 seconds, and the area change rate (D area %) after the heat treatment was measured. Table 3 summarizes the area change rate measurement results. While Examples 1 and 3 did not show significant area changes upon heat treatment, Comparative Example 11 showed significant dimensional changes, indicating that heat resistance cannot be achieved using only a polyethylene microporous film.

[0256] Table 3

[0257] Example# <![CDATA[D 面积 (%)@150℃ / 30s]]> <![CDATA[D 面积 (%)@170℃ / 30s]]> Example 1 -5.4 -8.3 Example 3 -6.3 -5.9 Comparative Example -67 -82

[0258] Laminate Examples

[0259] Nylon woven fabric for surface textiles

[0260] A plain nylon fabric made by Asahi Kasei Corporation without dyeing process was prepared, which was composed of 33 dtex bright filament yarn. The textile showed a translucent appearance.

[0261] Lamination and waterproofing

[0262] Example 1A

[0263] To adhere the above-mentioned surface textile to the film obtained in Example 1, a polyurethane-based moisture-curing hot melt adhesive ("Tyforce NH-320" manufactured by DIC Corporation) was used. The temperature of the adhesive was set to 110 degrees Celsius. The adhesive melt was applied in a dot pattern to the opposite surface of the hydrophilic polymer coating side of the film using a gravure roll with a coverage of 40%, so that the amount of adhesive transferred was 5 g / m 2 Subsequently, the surface textile and the film of Example 1 were pressed together with a roller and allowed to stand in a constant temperature and humidity chamber at 40 degrees Celsius and 80% RH for 24 hours to cure the hot melt adhesive, thereby obtaining a two-layer laminate.

[0264] Subsequently, the surface textile of the two-layer laminate was subjected to a fluorinated water repellent treatment by applying the fluorinated water repellent treatment to the surface of the surface textile in an amount exceeding the saturation level using a kisscoater, and squeezing the excess dispersion with a mangle roll to remove it.

[0265] At this time, the amount of dispersion absorbed by the surface fabric is about 20 g / m 2 The laminated product was then dried in a hot air circulation oven at 140 degrees Celsius for 30 seconds to obtain a two-layer laminated product that had been waterproofed.

[0266] Laminate 10A

[0267] The film of Comparative Example 10 was laminated in the same manner as Example 1A.

[0268] Laminate 11A

[0269] The film of Comparative Example 11 was laminated in the same manner as Example 1A, except that the heating temperature during the water repellent treatment was 90 degrees Celsius for 60 seconds.

[0270] Laminate appearance

[0271] Laminate Example 1A exhibited a translucent appearance, and Laminate Examples 10A and 11A exhibited an opaque white appearance derived from the color of the laminated films.

[0272] Test results of laminates

[0273] Home washing machine and water permeability test results

[0274] After five home washes with detergent, the laminated samples obtained in the above embodiments were hung at room temperature and dried. When water pressure was applied from the fabric side of the laminate to measure water pressure resistance, both Example 1A and Example 11A maintained the initial water pressure resistance of 9.8 kPa. On the other hand, in the samples that had been washed at home five times, no water leakage was confirmed in Example 1A, while water leakage was observed in Example 11A at pressures as high as 9.8 kPa. In addition, after five home washes, the appearance of the laminate of Example 1A remained translucent even in the wet area after the waterproof test, and no significant contrast was observed between the dry and wet areas. After five home washes, the appearance of Example 11A became translucent in the wet area after the waterproof test, and a significant contrast was produced between the dry and wet areas. This change in appearance is believed to be due to the film layer in the laminate changing from opaque white to translucent due to the porous layer being wetted by water. By washing the laminated samples, the detergent contaminated the porous polyethylene film and changed the film from hydrophobic to hydrophilic. On the other hand, the film of Example 1A did not contain a porous layer, so no water entered the film during the water resistance test.

[0275] The laminate of Example 10A maintained a water pressure resistance of 9.8 kPa both before and after five home wash and drying cycles. However, after five home washes, the appearance of the wetted portion of the laminate changed from opaque white to translucent upon application of water pressure, similar to Example 11A. Even though Example 10A maintains its water resistance after home washing, this change in appearance can be problematic: for example, by forming translucent areas, resulting in an overall uneven and undesirable appearance when used as clothing, affecting its aesthetic appeal.

[0276] Although many embodiments of the present invention have been described, it should be understood that these embodiments are illustrative only and not restrictive, and many modifications will become apparent to those skilled in the art. For example, all dimensions discussed herein are provided as examples only and are intended to be illustrative rather than restrictive.

Claims

1. A film comprising: A) microporous polyethylene membrane, wherein the microporous polyethylene membrane comprises polyethylene, wherein the weight average molecular weight of the polyethylene is greater than 500,000 g / mol, wherein the porosity of the microporous polyethylene membrane is at least 40% by volume, and wherein the microporous polyethylene membrane has a Gurley number of less than 200 seconds; and B) a hydrophilic polymer, wherein some of the hydrophilic polymer is located within at least a portion of the pores of the microporous polyethylene membrane, and at least some of the hydrophilic polymer forms a capping layer present on at least one surface of the microporous polyethylene membrane, and The cap layer is substantially free of voids.

2. The film according to claim 1, The hydrophilic polymer in the microporous polyethylene membrane substantially fills all pores of the microporous polyethylene membrane.

3. The film according to claim 1 or 2, further comprising a release layer, The release layer is adjacent to the cover layer.

4. The film according to claim 1, The cap layer has a controlled surface morphology.

5. The film of claim 4, wherein the controlled surface morphology comprises a surface transferred from a release layer disposed on the cover layer. The film according to claim 1 , having an opacity of 10 to 85.

7. The film according to claim 1, which has a heat resistance of no more than 190 degrees Celsius.

8. The film according to claim 1, which has a tensile strength in the MD direction of 0.45 kgf or more.

9. The film according to claim 1, which has a tensile strength in the TD direction of 0.36 kgf or more.

10. The film of claim 1, wherein the hydrophilic polymer comprises polyurethane, polyamide, polyester, epoxy resin, silicone resin, ionomer, or copolymers or combinations thereof.

11. The film according to claim 1, having a Gurley number of 1000 seconds or more.

12. The film of claim 1, having a surface gloss of 3.0 gloss units or greater.

13. The film according to claim 1, having a water vapor permeability of 2500 g / m 2 / day or more.

14. An article comprising the film of any one of claims 1 to 13.

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