Expanded polytetrafluoroethylene-based film-type mist absorber film and preparation method therefor

Abstract

An expanded polytetrafluoroethylene-based film-type mist absorber film and a preparation method therefor. A support framework layer (2) of the film is an expanded polytetrafluoroethylene film having a microporous structure; a mist absorber paste forms a mist absorbing functional layer (1) on the surface of the expanded polytetrafluoroethylene film; the mist absorber paste is embedded in the microporous structure to form active filling. During preparation, a solvent, a coupling agent and mist absorber powder are added to organic binder resin, which is then applied to an expanded polytetrafluoroethylene film by using a high-precision surface controllable coating composite technology, so as to prepare a film.

Description

A expanded polytetrafluoroethylene thin-film type defogging agent film and its preparation method Technical Field

[0001] This invention relates to the field of desiccant technology, and in particular to an expanded polytetrafluoroethylene film-type desiccant membrane and its preparation method. Background Technology

[0002] Currently, traditional demisting agents are generally powdered inorganic materials with micro- and nano-sized particles, typically including zeolites, molecular sieves, calcium oxide, calcium chloride, magnesium oxide, magnesium chloride, sodium chloride, aluminum hydroxide, and silica. Under normal operation, the moisture absorption mechanism of demisting agents includes chemical adsorption and nanoporous physical adsorption. Specifically, zeolites, molecular sieves, and mesoporous materials adsorb moisture through physical adsorption; alkaline earth metal oxides react with water to form hydroxides for chemical adsorption; additionally, some salts with hygroscopic properties can be used to absorb moisture. Micro- and nano-sized powdered inorganic demisting agents have excellent moisture absorption capacity due to their outstanding specific surface area. However, in actual production and application cases, powdered demisting agents can lead to cumbersome operation and cleanliness issues. Powder leakage and overflow can occur during the filling and use processes, affecting the product's appearance quality and the cleanliness level of the service environment. In practical applications, powdered inorganic defogging agents must be sealed with appropriate containers and flexible packaging materials before they can be used. In some specific applications with limited space, it is difficult to use them due to the limited volume of the corresponding external packaging containers.

[0003] In addition, most powdered inorganic defogging agents are irreversible and cannot be recycled multiple times. When they reach a saturation equilibrium state, they cannot be desorbed, or the desorption conditions are too harsh to meet the reversible start-up conditions, resulting in high humidity in the service environment and affecting the service life of the entire device. Summary of the Invention

[0004] The main technical problem solved by this invention is to provide an expanded polytetrafluoroethylene film-type defogging agent and its preparation method, which can achieve long-term effectiveness in moisture absorption and desorption capabilities, enabling multiple adsorption-desorption cycles for reuse, thereby achieving long-term effective control of humidity in the service environment.

[0005] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is: to provide an expanded polytetrafluoroethylene film-type defogging agent film, comprising: a supporting skeleton layer, a functional layer and an active filler, wherein the functional layer is composited on at least one side surface of the supporting skeleton layer, and the active filler is embedded in the supporting skeleton layer; wherein the supporting skeleton layer is an expanded polytetrafluoroethylene film with a microporous structure, and the defogging agent slurry forms a defogging functional layer on at least one side surface of the expanded polytetrafluoroethylene film, and the defogging agent slurry is embedded in the microporous structure to form an active filler.

[0006] In a preferred embodiment of the present invention, the expanded polytetrafluoroethylene membrane is a single-stretched or double-stretched membrane with a thickness of 5 to 300 μm and a pore size range of 0.1 to 30 μm.

[0007] In a preferred embodiment of the present invention, the membrane thickness is 50 ~ 300 μm, and the basis weight per unit area is ≤200 g / m². 2 .

[0008] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is: a method for preparing an expanded polytetrafluoroethylene film-type defogging agent film, comprising the following steps:

[0009] 1) Add the solvent, coupling agent and defogging agent powder to the organic binder resin according to the proportion, mix and disperse evenly to obtain defogging agent slurry, then grind the defogging agent slurry further, collect it and set aside for use;

[0010] 2) The defogging agent slurry from step 1) is applied to an expanded polytetrafluoroethylene film using a high-precision surface controllable coating composite technology, and then dried and cured at high temperature to form a film.

[0011] 3) The membrane from step 2) is slit and precision die-cut to obtain expanded polytetrafluoroethylene thin film type defogging agent film.

[0012] In a preferred embodiment of the present invention, the coupling agent is one or more of the following: γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltriethoxysilane, anilinemethyltriethoxysilane, titanate coupling agent, zirconate coupling agent, phosphorus-containing coupling agent, and boron-containing coupling agent.

[0013] In a preferred embodiment of the present invention, the active mist absorber powder includes one or more of the following: zeolite, molecular sieve, calcium oxide, calcium chloride, magnesium oxide, magnesium chloride, sodium chloride, aluminum hydroxide, and silicon dioxide, wherein the mass ratio of magnesium oxide to magnesium chloride is 25 wt% to 70 wt%.

[0014] In a preferred embodiment of the present invention, the organic binder resin includes one or more of polyacrylate resin, polyurethane resin, epoxy resin, silicone-modified acrylic resin and mercapto-silicone oligomer resin.

[0015] In a preferred embodiment of the present invention, the grinding is performed 2-4 times, with each grinding session lasting 10 minutes, and the viscosity is controlled to be ≤1500 mPa·s.

[0016] In a preferred embodiment of the present invention, the temperature for high-temperature drying and curing to form a film is 100℃±50℃.

[0017] In a preferred embodiment of the present invention, the weight parts of solvent, coupling agent, defogging agent powder and organic binder resin are as follows: 100 parts organic binder resin; 2.5-25 parts coupling agent; 120-200 parts defogging agent powder; and 100-250 parts solvent.

[0018] The beneficial effects of this invention are as follows: This invention utilizes high-precision surface controllable coating composite technology to prepare expanded polytetrafluoroethylene film-type defogging agent membranes with high moisture absorption and durable reversible properties. Under conditions of 40℃ and 90%RH, the moisture absorption rate of the membrane can reach more than 140% of its own weight, exhibiting excellent high moisture absorption. In a moisture-saturated state, desorption can be achieved by placing the membrane in an environment of 35℃, with a desorption rate of more than 130%. The conditions for reversible desorption of the membrane are not harsh, and the desorption rate is high, with excellent adsorption-desorption cycle durability. It also has excellent flexibility and mechanical properties, with a tensile strength ≥3 MPa and an elongation at break ≥45%. Furthermore, it has excellent weather resistance and temperature resistance, with an operating temperature range of -60℃ to 120℃. In addition, due to its thinness, small size, and light weight per unit area, this invention is suitable for moisture-proof and anti-fogging treatment in confined spaces, such as electronic equipment and precision instruments, thus expanding its application scenarios and scope of application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0020] Figure 1 is a schematic diagram of a preferred embodiment of the expanded polytetrafluoroethylene film-type defogging agent film of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this invention, it should be noted that the terms "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] In this invention, unless otherwise expressly specified and limited, "above or below" a first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] Please refer to Figure 1. The embodiments of the present invention include: Example

[0028] An expanded polytetrafluoroethylene film-type defogging agent film includes: a supporting skeleton layer 2, a functional layer 1, and an active filler. The functional layer 1 is laminated on at least one side surface of the supporting skeleton layer 2. Preferably, the supporting skeleton layer 2 is laminated with the functional layer 1 on both the top and bottom, and the active filler is embedded in the supporting skeleton layer 2.

[0029] In this invention, the supporting skeleton layer 2 is an expanded polytetrafluoroethylene membrane with a microporous structure, and the mist absorber slurry forms a mist-absorbing functional layer 1 on the upper and lower surfaces of the expanded polytetrafluoroethylene membrane. The mist absorber slurry is embedded in the microporous structure to form an active filler.

[0030] The expanded polytetrafluoroethylene (ePTFE) membrane is a single-stretched or double-stretched membrane with a thickness of 5 to 300 μm. The pore size of the ePTFE membrane ranges from 0.1 to 30 μm. There are hundreds of millions of irregularly shaped, staggered, three-dimensional micropores per square centimeter, and the material has a large number of interconnected micropores, which provide a certain degree of air permeability and moisture permeability.

[0031] The membrane thickness is 50 ~ 300 μm, and the basis weight per unit area is ≤200 g / m². 2 It possesses excellent flexibility and mechanical properties, with a tensile strength ≥3 MPa and an elongation at break ≥45%; it also exhibits excellent weather resistance and temperature resistance, with an operating temperature range of -60℃ to 120℃; due to its thinness, small size, and light weight per unit area, it is suitable for use in confined spaces, such as for moisture-proofing and anti-fog treatment of electronic equipment and precision instruments, thus expanding its application scenarios and scope of application.

[0032] The method for preparing the expanded polytetrafluoroethylene film-type defogging agent of the present invention includes the following steps:

[0033] 150 parts by weight of solvent, 10 parts by weight of coupling agent, and 140 parts by weight of defogging agent powder were added to 100 parts by weight of organic binder resin and mixed and dispersed evenly to obtain a defogging agent slurry. The defogging agent slurry was then further ground twice, with each grinding time being 10 min, to prepare a defogging agent slurry with a measured viscosity of 1300 mPa·s. The above defogging agent slurry was coated onto an expanded polytetrafluoroethylene (ePTFE) film using a high-precision surface controllable coating composite technology. After high-temperature drying and curing at 120°C, the film was then slit and precision die-cut to obtain an ePTFE film-type defogging agent film with a thickness of 160 μm and a basis weight of 150 g / m². 2 . Example

[0034] An expanded polytetrafluoroethylene film-type defogging agent film includes: a supporting skeleton layer 2, a functional layer 1, and an active filler. The functional layer 1 is laminated on at least one side surface of the supporting skeleton layer 2. Preferably, the supporting skeleton layer 2 is laminated with the functional layer 1 on both the top and bottom, and the active filler is embedded in the supporting skeleton layer 2.

[0035] In this invention, the supporting skeleton layer 2 is an expanded polytetrafluoroethylene membrane with a microporous structure, and the mist absorber slurry forms a mist-absorbing functional layer 1 on the upper and lower surfaces of the expanded polytetrafluoroethylene membrane. The mist absorber slurry is embedded in the microporous structure to form an active filler.

[0036] The expanded polytetrafluoroethylene (ePTFE) membrane is a single-stretched or double-stretched membrane with a thickness of 5 to 300 μm. The pore size of the ePTFE membrane ranges from 0.1 to 30 μm. There are hundreds of millions of irregularly shaped, staggered, three-dimensional micropores per square centimeter, and the material has a large number of interconnected micropores, which provide a certain degree of air permeability and moisture permeability.

[0037] The membrane thickness is 50 ~ 300 μm, and the basis weight per unit area is ≤200 g / m². 2 It possesses excellent flexibility and mechanical properties, with a tensile strength ≥3 MPa and an elongation at break ≥45%; it also exhibits excellent weather resistance and temperature resistance, with an operating temperature range of -60℃ to 120℃; due to its thinness, small size, and light weight per unit area, it is suitable for use in confined spaces, such as for moisture-proofing and anti-fog treatment of electronic equipment and precision instruments, thus expanding its application scenarios and scope of application.

[0038] The method for preparing the expanded polytetrafluoroethylene film-type defogging agent of the present invention includes the following steps:

[0039] 150 parts by weight of solvent, 10 parts by weight of coupling agent, and 140 parts by weight of defogging agent powder were added to 100 parts by weight of organic binder resin and mixed and dispersed evenly to obtain a defogging agent slurry. The defogging agent slurry was then further ground four times, with each grinding time being 10 minutes, to prepare a defogging agent slurry with a measured viscosity of 1150 mPa·s. The above defogging agent slurry was coated onto an expanded polytetrafluoroethylene (ePTFE) film using a high-precision surface controllable coating composite technology. After high-temperature drying and curing at 120°C, the film was then slit and precision die-cut to obtain an ePTFE film-type defogging agent film with a thickness of 140 μm and a basis weight of 135 g / m². 2 . Example

[0040] An expanded polytetrafluoroethylene film-type defogging agent film includes: a supporting skeleton layer 2, a functional layer 1, and an active filler. The functional layer 1 is laminated on at least one side surface of the supporting skeleton layer 2. Preferably, the supporting skeleton layer 2 is laminated with the functional layer 1 on both the top and bottom, and the active filler is embedded in the supporting skeleton layer 2.

[0041] In this invention, the supporting skeleton layer 2 is an expanded polytetrafluoroethylene membrane with a microporous structure, and the mist absorber slurry forms a mist-absorbing functional layer 1 on the upper and lower surfaces of the expanded polytetrafluoroethylene membrane. The mist absorber slurry is embedded in the microporous structure to form an active filler.

[0042] The expanded polytetrafluoroethylene (ePTFE) membrane is a single-stretched or double-stretched membrane with a thickness of 5 to 300 μm. The pore size of the ePTFE membrane ranges from 0.1 to 30 μm. There are hundreds of millions of irregularly shaped, staggered, three-dimensional micropores per square centimeter, and the material has a large number of interconnected micropores, which provide a certain degree of air permeability and moisture permeability.

[0043] The membrane thickness is 50 ~ 300 μm, and the basis weight per unit area is ≤200 g / m². 2 It possesses excellent flexibility and mechanical properties, with a tensile strength ≥3 MPa and an elongation at break ≥45%; it also exhibits excellent weather resistance and temperature resistance, with an operating temperature range of -60℃ to 120℃; due to its thinness, small size, and light weight per unit area, it is suitable for use in confined spaces, such as for moisture-proofing and anti-fog treatment of electronic equipment and precision instruments, thus expanding its application scenarios and scope of application.

[0044] The method for preparing the expanded polytetrafluoroethylene film-type defogging agent of the present invention includes the following steps:

[0045] 110 parts by weight of solvent, 15 parts by weight of coupling agent, and 150 parts by weight of defogging agent powder were added to 100 parts by weight of organic binder resin and mixed and dispersed evenly to obtain a defogging agent slurry. The defogging agent slurry was then further ground twice, with each grinding time being 10 min, to prepare a defogging agent slurry with a measured viscosity of 1430 mPa·s. The above defogging agent slurry was coated onto an expanded polytetrafluoroethylene (ePTFE) film using a high-precision surface controllable coating composite technology. After high-temperature drying and curing at 120°C, the film was then slit and precision die-cut to obtain an ePTFE film-type defogging agent film with a thickness of 255 μm and a basis weight of 192 g / m². 2 . Example

[0046] An expanded polytetrafluoroethylene film-type defogging agent film includes: a supporting skeleton layer 2, a functional layer 1, and an active filler. The functional layer 1 is laminated on at least one side surface of the supporting skeleton layer 2. Preferably, the supporting skeleton layer 2 is laminated with the functional layer 1 on both the top and bottom, and the active filler is embedded in the supporting skeleton layer 2.

[0047] In this invention, the supporting skeleton layer 2 is an expanded polytetrafluoroethylene membrane with a microporous structure, and the mist absorber slurry forms a mist-absorbing functional layer 1 on the upper and lower surfaces of the expanded polytetrafluoroethylene membrane. The mist absorber slurry is embedded in the microporous structure to form an active filler.

[0048] The expanded polytetrafluoroethylene (ePTFE) membrane is a single-stretched or double-stretched membrane with a thickness of 5 to 300 μm. The pore size of the ePTFE membrane ranges from 0.1 to 30 μm. There are hundreds of millions of irregularly shaped, staggered, three-dimensional micropores per square centimeter, and the material has a large number of interconnected micropores, which provide a certain degree of air permeability and moisture permeability.

[0049] The membrane thickness is 50 ~ 300 μm, and the basis weight per unit area is ≤200 g / m². 2 It possesses excellent flexibility and mechanical properties, with a tensile strength ≥3 MPa and an elongation at break ≥45%; it also exhibits excellent weather resistance and temperature resistance, with an operating temperature range of -60℃ to 120℃; due to its thinness, small size, and light weight per unit area, it is suitable for use in confined spaces, such as for moisture-proofing and anti-fog treatment of electronic equipment and precision instruments, thus expanding its application scenarios and scope of application.

[0050] The method for preparing the expanded polytetrafluoroethylene film-type defogging agent of the present invention includes the following steps:

[0051] 110 parts by weight of solvent, 15 parts by weight of coupling agent, and 150 parts by weight of defogging agent powder were added to 100 parts by weight of organic binder resin and mixed and dispersed evenly to obtain a defogging agent slurry. The defogging agent slurry was then further ground four times, with each grinding time being 10 minutes, to prepare a defogging agent slurry with a measured viscosity of 1380 mPa·s. The above defogging agent slurry was coated onto an expanded polytetrafluoroethylene (ePTFE) film using a high-precision surface controllable coating composite technology. After high-temperature drying and curing at 120°C, the film was then slit and precision die-cut to obtain an ePTFE film-type defogging agent film with a thickness of 225 μm and a basis weight of 180 g / m². 2 . Example

[0052] An expanded polytetrafluoroethylene film-type defogging agent film includes: a supporting skeleton layer 2, a functional layer 1, and an active filler. The functional layer 1 is laminated on at least one side surface of the supporting skeleton layer 2. Preferably, the supporting skeleton layer 2 is laminated with the functional layer 1 on both the top and bottom, and the active filler is embedded in the supporting skeleton layer 2.

[0053] In this invention, the supporting skeleton layer 2 is an expanded polytetrafluoroethylene membrane with a microporous structure, and the mist absorber slurry forms a mist-absorbing functional layer 1 on the upper and lower surfaces of the expanded polytetrafluoroethylene membrane. The mist absorber slurry is embedded in the microporous structure to form an active filler.

[0054] The expanded polytetrafluoroethylene (ePTFE) membrane is a single-stretched or double-stretched membrane with a thickness of 5 to 300 μm. The pore size of the ePTFE membrane ranges from 0.1 to 30 μm. There are hundreds of millions of irregularly shaped, staggered, three-dimensional micropores per square centimeter, and the material has a large number of interconnected micropores, which provide a certain degree of air permeability and moisture permeability.

[0055] The membrane thickness is 50 ~ 300 μm, and the basis weight per unit area is ≤200 g / m². 2 It possesses excellent flexibility and mechanical properties, with a tensile strength ≥3 MPa and an elongation at break ≥45%; it also exhibits excellent weather resistance and temperature resistance, with an operating temperature range of -60℃ to 120℃; due to its thinness, small size, and light weight per unit area, it is suitable for use in confined spaces, such as for moisture-proofing and anti-fog treatment of electronic equipment and precision instruments, thus expanding its application scenarios and scope of application.

[0056] The method for preparing the expanded polytetrafluoroethylene film-type defogging agent of the present invention includes the following steps:

[0057] 190 parts by weight of solvent, 10 parts by weight of coupling agent, and 130 parts by weight of defogging agent powder were added to 100 parts by weight of organic binder resin and mixed and dispersed evenly to obtain a defogging agent slurry. The defogging agent slurry was then further ground four times, with each grinding time being 10 minutes, to prepare a defogging agent slurry with a measured viscosity of 900 mPa·s. The above defogging agent slurry was coated onto an expanded polytetrafluoroethylene (ePTFE) film using a high-precision surface controllable coating composite technology. After high-temperature drying and curing at 120°C, the film was then slit and precision die-cut to obtain an ePTFE film-type defogging agent film with a thickness of 110 μm and a basis weight of 100 g / m². 2 .

[0058] In embodiments 1-5 above, the coupling agent is one or more of the following: γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltriethoxysilane, anilinemethyltriethoxysilane, titanate coupling agent, zirconate coupling agent, phosphorus-containing coupling agent, and boron-containing coupling agent, and is further preferably γ-(methacryloyloxy)propyltrimethoxysilane.

[0059] The active mist absorber powder includes one or more of the following: zeolite, molecular sieve, calcium oxide, calcium chloride, magnesium oxide, magnesium chloride, sodium chloride, aluminum hydroxide, and silicon dioxide. Among them, magnesium oxide and magnesium chloride are preferred, and the mass ratio of addition is 25 wt% to 70 wt%.

[0060] Organic adhesive resins include one or more of polyacrylate resins, polyurethane resins, epoxy resins, silicone-modified acrylic resins, and mercapto-silicone oligomer resins.

[0061] The expanded polytetrafluoroethylene film-type defogging agent membrane prepared by the above preparation method can replace the traditional defogging agent powder, overcome the problems of filling difficulties, powder overflow and leakage of traditional powdered defogging agents, and can be used in fields with high cleanliness requirements.

[0062] The performance of the expanded polytetrafluoroethylene thin film type defogging agent films prepared in Examples 1-5 above was tested, and the details are shown in Table 1.

[0063] Table 1. Performance of expanded polytetrafluoroethylene film-type fog absorbers

[0064] Number of grinding cycles, viscosity (mPa·s), thickness (μm), and basis weight (g / m²) of the sample. 2 Moisture absorption rate (%) Desorption rate (%) Example 1 2 1300 160 150 157.0 149.5 Example 2 4 1150 140 135 152.5 141.0 Example 3 2 1430 255 192 170.5 163.5 Example 4 4 ​​1380 225 180 165.8 153.5 Example 5 4900 110 100 142.0 135.8

[0065] Therefore, it can be seen that the expanded polytetrafluoroethylene film-type defogging agent membrane prepared by high-precision surface controllable coating composite technology has a high moisture absorption rate and durable reversible properties. Under the conditions of 40℃ and 90%RH, the moisture absorption rate of the membrane can reach more than 140% of its own weight, which has excellent high moisture absorption rate. Under the moisture saturation state, the membrane can be desorbed by placing it in an environment of 35℃, with a desorption rate of more than 130%. The reversible start-up conditions for membrane desorption are not harsh, and the desorption rate is high. It also has excellent adsorption-desorption cycle durability, thereby enabling long-term and effective control of humidity in the service environment.

[0066] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An expanded polytetrafluoroethylene film-type fog desiccant sheet, characterized in that, include: The support skeleton layer, the functional layer and the active filler are combined, wherein the functional layer is composited on at least one surface of the support skeleton layer and the active filler is embedded in the support skeleton layer. The supporting skeleton layer is an expanded polytetrafluoroethylene membrane with a microporous structure. The mist absorber slurry forms a mist-absorbing functional layer on at least one side surface of the expanded polytetrafluoroethylene membrane, and the mist absorber slurry is embedded in the microporous structure to form an active filler.

2. The expanded polytetrafluoroethylene film-type fog desiccant sheet according to claim 1, characterized in that, The expanded polytetrafluoroethylene membrane is a single-stretched or double-stretched membrane with a thickness of 5 to 300 μm and a pore size range of 0.1 to 30 μm.

3. The expanded polytetrafluoroethylene film-type fog desiccant sheet according to claim 1, characterized in that, The membrane thickness is 50 ~ 300 μm, and the basis weight per unit area is ≤200 g / m². 2 .

4. The method for preparing the expanded polytetrafluoroethylene film-type defogging agent membrane according to claim 1, characterized in that, Includes the following steps: 1) Add the solvent, coupling agent and defogging agent powder to the organic binder resin according to the proportion, mix and disperse evenly to obtain defogging agent slurry, then grind the defogging agent slurry further, collect it and set aside for use; 2) The defogging agent slurry from step 1) is applied to an expanded polytetrafluoroethylene film using a high-precision surface controllable coating composite technology, and then dried and cured at high temperature to form a film. 3) The membrane from step 2) is slit and precision die-cut to obtain expanded polytetrafluoroethylene thin film type defogging agent film.

5. The method for preparing the expanded polytetrafluoroethylene film-type defogging agent membrane according to claim 4, characterized in that, The coupling agent is one or more of the following: γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltriethoxysilane, anilinemethyltriethoxysilane, titanate coupling agent, zirconate coupling agent, phosphorus-containing coupling agent, and boron-containing coupling agent.

6. The method for preparing the expanded polytetrafluoroethylene film-type defogging agent membrane according to claim 4, characterized in that, The active mist absorber powder includes one or more of the following: zeolite, molecular sieve, calcium oxide, calcium chloride, magnesium oxide, magnesium chloride, sodium chloride, aluminum hydroxide, and silicon dioxide, wherein the mass ratio of magnesium oxide to magnesium chloride is 25 wt% to 70 wt%.

7. The method for preparing the expanded polytetrafluoroethylene film-type defogging agent membrane according to claim 4, characterized in that, The organic binder resin includes one or more of polyacrylate resin, polyurethane resin, epoxy resin, silicone-modified acrylic resin, and mercapto-silicone oligomer resin.

8. The method for preparing the expanded polytetrafluoroethylene film-type defogging agent membrane according to claim 4, characterized in that, The grinding process is repeated 2-4 times, with each grinding session lasting 10 minutes, and the viscosity is controlled to be ≤1500 mPa·s.

9. The method for preparing the expanded polytetrafluoroethylene film-type defogging agent membrane according to claim 4, characterized in that, The temperature for high-temperature drying and curing to form a film is 100℃±50℃.

10. The method for preparing the expanded polytetrafluoroethylene film-type defogging agent membrane according to claim 4, characterized in that, The weight parts of solvent, coupling agent, defogging agent powder and organic binder resin are as follows: 100 parts organic binder resin; 2.5-25 parts coupling agent; 120-200 parts defogging agent powder; 100-250 parts solvent.

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