Liquid-repellent film and liquid-repellent article

Abstract

To provide a liquid-repellent film capable of suppressing decrease in liquid repellency resulting from long-time contact with a liquid.SOLUTION: A liquid-repellent film 40 has a hydrophilic fine particle 41 and a coating part 42 for covering the hydrophilic fine particle 41. The hydrophilic fine particle 41 has a BET specific surface area of 15 m2 / g or more. The coating part 42 includes a methacrylate copolymer. The methacrylate copolymer is a copolymer of a plurality of types of monomers including a first monomer which is a methacrylate monomer having a perfluoroalkyl group and a second monomer which is a methacrylate monomer having an alkoxysilyl group. In the methacrylate copolymer, the ratio of the constitutional unit derived from the first monomer is 80 mol% or more and 98 mol% or less and the ratio of the constitutional unit derived from the second monomer is 2 mol% or more and 13 mol% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention provides a liquid-repellent film. , and liquid-repellent articles Regarding. [Background technology]

[0002] Liquid-repellent films are known that have a surface with irregularities made up of many fine particles. Because the irregularities made up of the fine particles are minute, liquids do not easily penetrate into the irregularities. Therefore, liquids that come into contact with the liquid-repellent film slide off the surface of the film, thereby exhibiting liquid-repellent properties. To enhance the liquid-repellent properties, the liquid-repellent film has a coating containing a fluorine material, and the coating coats the fine particles in a film-like manner (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5242841 [Patent Document 2] Patent No. 5114355 Summary of the Invention [Problem to be solved by the invention]

[0004] When a liquid-repellent film is used on a surface that will be in contact with a liquid for a long period of time, such as the inner surface of a container that contains the liquid, it is desirable that the liquid-repellent properties of the film be maintained even after the film has been in contact with the liquid for a long period of time. To date, various improvements have been made to the properties of the liquid-repellent film, such as the material and surface roughness, from the perspective of improving the liquid-repellent properties. However, little is known about the maintenance of the liquid-repellent properties, and there is still room for improvement in the configuration of the liquid-repellent film. [Means for solving the problem]

[0005] The liquid-repellent film for solving the above problems is a liquid-repellent film having hydrophilic fine particles and a coating portion covering the hydrophilic fine particles, wherein the BET specific surface area of ​​the hydrophilic fine particles is 15 m 2 / g or more, the coating portion includes a methacrylate copolymer, the methacrylate copolymer is a copolymer of multiple types of monomers including a first monomer which is a methacrylate monomer having a perfluoroalkyl group and a second monomer which is a methacrylate monomer having an alkoxysilyl group, the ratio of constitutional units derived from the first monomer in the methacrylate copolymer is 80 mol % or more and 98 mol % or less, and the ratio of constitutional units derived from the second monomer in the methacrylate copolymer is 2 mol % or more and 13 mol % or less.

[0006] According to the above configuration, covalent bonds are formed between the polymer chains or between the polymer chains and the surface of the hydrophilic fine particles based on the alkoxysilyl groups. The progress of this reaction prevents the coating from being altered, such as elution or unevenness, when the liquid-repellent film is in contact with the liquid to be repelled. Therefore, the deterioration of the liquid-repellent properties of the liquid-repellent film is prevented.

[0007] In the above configuration, the hydrophilic fine particles may be silica particles or titanium oxide particles. According to the above-mentioned configuration, the reactivity of the reaction between the alkoxysilyl group-based copolymer and the hydrophilic fine particles is increased.

[0008] In the above configuration, the second monomer may be any one of 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane. According to the above-mentioned configuration, the reaction based on the alkoxysilyl group proceeds smoothly, and the monomer is easily available.

[0009] In the above configuration, the hydrophilic microparticles may be silica particles, the ratio of the F atom concentration to the Si atom concentration in the liquid-repellent film may be the element ratio, the immersion test may be a test in which the liquid-repellent film is immersed in an aqueous ethanol solution with a concentration of 50% by mass for 72 hours, and the ratio of the element ratio of the liquid-repellent film after the immersion test to the element ratio of the liquid-repellent film before the immersion test may be 0.8 or more.

[0010] In the above configuration, the hydrophilic fine particles may be titanium oxide particles, the ratio of the F atom concentration to the Ti atom concentration in the liquid-repellent film may be the element ratio, the immersion test may be a test in which the liquid-repellent film is immersed in an aqueous ethanol solution with a concentration of 50% by mass for 72 hours, and the ratio of the element ratio of the liquid-repellent film after the immersion test to the element ratio of the liquid-repellent film before the immersion test may be 0.8 or more. According to the above-mentioned configurations, deterioration of the coating portion due to immersion in the ethanol aqueous solution can be effectively prevented, and therefore, deterioration of the liquid repellency of the liquid repellent film can be effectively prevented.

[0011] In the above configuration, the immersion test may be a test in which the liquid-repellent film is immersed in an aqueous ethanol solution with a concentration of 50% by mass for 72 hours, and the sliding angle of the aqueous ethanol solution with a concentration of 50% by mass on the liquid-repellent film after the immersion test may be 25° or less. According to the above configuration, the deterioration of the liquid repellency of the liquid repellent film due to immersion in an ethanol aqueous solution can be suitably suppressed.

[0012] In the above configuration, when the total weight of the methacrylate copolymer contained in the liquid-repellent film is Mp, the total weight of the hydrophilic fine particles contained in the liquid-repellent film is Mf, and the average primary particle diameter of the hydrophilic fine particles is R (nm), the weight Mp, the weight Mf, and the particle diameter R may satisfy the following formula (1): 9≦R×(Mp / Mf)≦35 Formula (1)

[0013] According to the above-mentioned configuration, the ratio of the microparticles to the copolymer in the liquid-repellent film is optimized, taking into account the particle size of the microparticles. That is, the amount of copolymer relative to the hydrophilic microparticles is prevented from being too large or too small, and the specific surface area of ​​the hydrophilic microparticles is prevented from becoming excessively large. Therefore, the coating portion is easily formed along the unevenness caused by the chain of hydrophilic microparticles, and higher water repellency is easily achieved.

[0014] In the above configuration, the hydrophilic fine particles may have an average primary particle diameter of 20 nm or more. According to the above-mentioned configuration, the irregularities on the surface of the liquid-repellent film can be easily formed to a size suitable for liquid repellency, and therefore, higher liquid repellency can be easily obtained. In the above configuration, the arithmetic mean height Sa of the surface of the liquid-repellent film may be 1.2 μm or more. According to the above-mentioned configuration, since the surface of the liquid-repellent film is formed with unevenness of sufficient height, it becomes easier to obtain higher liquid repellency. [Effects of the Invention]

[0015] According to the present invention, it is possible to prevent the liquid-repellent film from losing its liquid-repellent properties due to prolonged contact with liquid. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing an example of a cross-sectional structure of a liquid-repellent article provided with a liquid-repellent film according to an embodiment. [Figure 2] 10A and 10B are diagrams showing another example of the cross-sectional structure of a liquid-repellent article provided with a liquid-repellent film according to an embodiment. [Figure 3] 10 is a graph showing the liquid repellency and element ratio retention rate before and after an immersion test for the liquid repellent film of the test example. DETAILED DESCRIPTION OF THE INVENTION

[0017] One embodiment of a liquid-repellent film will be described with reference to the drawings. The liquid-repellent film of this embodiment is disposed on the surface of a container or bag that contains a liquid, which comes into contact with the liquid, or on the surface of a sheet or molded product to which it is desired to prevent the adhesion of liquid. In particular, the liquid-repellent film of this embodiment is suitable for use on the inner surface of a container that comes into contact with liquid for a long period of time. An article equipped with a liquid-repellent film is a liquid-repellent article.

[0018] [Configuration of liquid-repellent article] 1, the liquid-repellent article 10 includes a support 20, an adhesive layer 30, and a liquid-repellent film 40. The adhesive layer 30 is sandwiched between the support 20 and the liquid-repellent film 40. The liquid-repellent film 40 includes hydrophilic fine particles 41 and a coating portion 42.

[0019] The liquid-repellent article 10 is, for example, a container that contains liquids used as daily necessities such as hair care products, body care products, cosmetics, and detergents, or a sheet that is provided on the surface of such a container that comes into contact with liquid.

[0020] The material of the support 20 is not particularly limited, and the materials of the support 20 and the adhesive layer 30 may be selected so that the adhesive layer 30 can be adhered to the surface of the support 20. Examples of materials for the support 20 include resins such as polyethylene, polypropylene, polyethylene terephthalate, polystyrene, and acrylic, as well as glass and metal. The support 20 may be in the form of a sheet, or may be a molded product having a shape different from a sheet.

[0021] The adhesive layer 30 is a layer for improving adhesion between the support 20 and the liquid-repellent film 40. The material of the adhesive layer 30 is an adhesive resin such as a polyolefin resin or a polyurethane resin. Note that if sufficient adhesion between the support 20 and the liquid-repellent film 40 can be obtained without using the adhesive layer 30, the liquid-repellent article 10 does not need to include the adhesive layer 30.

[0022] The hydrophilic microparticles 41 are hydrophilic microparticles. The material of the hydrophilic microparticles 41 is, for example, silica or a metal oxide such as titanium oxide. The liquid-repellent film 40 includes at least first hydrophilic microparticles 41 having a nano-order particle size. In addition to the first hydrophilic microparticles 41, the liquid-repellent film 40 may also include second hydrophilic microparticles 41 having a micro-order particle size. The coating portion 42 coats the hydrophilic fine particles 41. The coating portion 42 contains a methacrylate copolymer having a perfluoroalkyl group.

[0023] The surface of the liquid-repellent article 10, i.e., the surface of the liquid-repellent film 40, has minute irregularities along the chain of numerous hydrophilic microparticles 41. Because liquids do not easily penetrate these irregularities, liquids that come into contact with the surface of the liquid-repellent film 40 are more likely to be repelled. If the liquid-repellent film 40 contains second hydrophilic microparticles 41 in addition to the first hydrophilic microparticles 41, the irregularities on the surface of the liquid-repellent film 40 become more complex, and liquids that come into contact with the surface of the liquid-repellent film 40 are more likely to be repelled.

[0024] 2, the adhesive layer 30 may contain large-diameter particles 31 in an adhesive resin. The material of the large-diameter particles 31 is, for example, silica, silicone, acrylic resin, urethane resin, etc. The particle diameter of the large-diameter particles 31 is larger than the particle diameter of the first hydrophilic particles 41, and the large-diameter particles 31 have a particle diameter on the order of microns.

[0025] Since the adhesive layer 30 contains large-diameter microparticles 31, the surface of the adhesive layer 30 has irregularities that correspond to the large-diameter microparticles 31, and the hydrophilic microparticles 41 of the liquid-repellent film 40 are aligned along the irregular surface of the adhesive layer 30. Therefore, the irregularities on the surface of the liquid-repellent film 40 become more complex, making it easier for liquids that come into contact with the surface of the liquid-repellent film 40 to be repelled.

[0026] [Liquid-repellent film composition] The liquids used in the above-mentioned daily necessities often contain water and ethanol. The inventors of the present application have discovered that when a liquid-repellent film is immersed in an ethanol aqueous solution, alteration of the coating, such as elution of the coating or uneven coating state, occurs, which is the cause of the decrease in liquid repellency. The inventors have also found that the alteration of the coating can be suppressed by improving the material of the coating. Incidentally, uneven coating state refers to loosening of the coating, causing the coating to flow over the hydrophilic fine particles, resulting in the exposure of some of the hydrophilic fine particles from the coating.

[0027] The following describes the liquid-repellent film 40 in detail, focusing on the configuration of the covering portion 42. The coating 42 includes a methacrylate copolymer. This copolymer is a copolymer of multiple types of monomers, including a first monomer that is a methacrylate monomer having a perfluoroalkyl group and a second monomer that is a methacrylate monomer having an alkoxysilyl group. This copolymer may be a random copolymer or a block copolymer.

[0028] The first monomer has a linear or branched perfluoroalkyl group having 1 to 6 carbon atoms. If the perfluoroalkyl group is linear and has 4 to 6 carbon atoms, this is preferable because it enhances the liquid repellency of the liquid-repellent film 40 and also makes it easy to obtain the monomer or copolymer. A specific example of the first monomer is 2-(perfluorohexyl)ethyl methacrylate.

[0029] The alkoxysilyl group of the second monomer preferably contains two or more methoxy or ethoxy groups. Specifically, the alkoxysilyl group is preferably any one of a methyldimethoxysilyl group, a trimethoxysilyl group, a methyldiethoxysilyl group, and a triethoxysilyl group. Specific examples of the second monomer include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane.

[0030] The monomers used to produce the methacrylate copolymer may include a third monomer different from the first and second monomers. The third monomer preferably does not contain a fluorine atom. The third monomer has, for example, a hydroxy group, an amide group, an ether group, a primary amine, a secondary amine, a tertiary amine, pyrrolidone, a hydrocarbon chain having 6 or more carbon atoms and not containing a fluorine atom, or a benzyl group.

[0031] It is preferable that the third monomer is a hydrophilic monomer, since this increases the affinity between the copolymer and the hydrophilic fine particles 41, making it easier for the hydrophilic fine particles 41 to be coated with the coating portions 42. From this viewpoint, it is preferable that the third monomer has any one of a hydroxy group, an amide group, an ether group, a primary amine, a secondary amine, and a tertiary amine.

[0032] Specific examples of the third monomer are 2-hydroxyethyl methacrylate, 2-(diethylamino)ethyl methacrylate, diethylene glycol dimethacrylate, lauryl methacrylate, and benzyl methacrylate. The monomers used to produce the methacrylate copolymer may contain multiple types of third monomers having different functional groups.

[0033] The proportion Rm1 of the structural units derived from the first monomer in the methacrylate copolymer is 80 mol % or more and 98 mol % or less, and the proportion Rm2 of the structural units derived from the second monomer in the methacrylate copolymer is 2 mol % or more and 13 mol % or less.

[0034] When the methacrylate copolymer contains 2 mol % or more of the constitutional unit derived from the second monomer, covalent bonds are formed between the polymer chains or between the polymer chains and the surfaces of the hydrophilic microparticles 41. As crosslinking progresses in this manner, deterioration of the coating portion 42 is suppressed even when the liquid-repellent film 40 is in contact with the liquid to be repelled for a long period of time.

[0035] Furthermore, by setting the ratio Rm2 of the constitutional units derived from the second monomer to 13 mol % or less, the copolymer has favorable solubility in the solvent of the coating liquid for forming the liquid-repellent film 40. Therefore, the liquid-repellent film 40 in which the hydrophilic fine particles 41 are coated with the coating portion 42 can be favorably formed.

[0036] Furthermore, by having the ratio Rm1 of the structural units derived from the first monomer be 80 mol % or more, the liquid repellency of the covering portion 42 is enhanced. In particular, even when the copolymer contains structural units derived from the third monomer, the copolymer is prevented from becoming too hydrophilic, making it difficult for the copolymer to swell or dissolve in aqueous liquids. This improves the liquid repellency to liquids containing water.

[0037] The above-mentioned crosslinking progresses as follows: after the formation of the liquid-repellent film 40, moisture in the atmosphere gradually hydrolyzes the alkoxysilyl groups of the copolymer, and the resulting silanol groups undergo dehydration condensation between polymer chains or between the polymer chains and the surfaces of the hydrophilic microparticles 41. Because this crosslinking progresses slowly in a room temperature environment, it is preferable to wait at least 24 hours after the formation of the liquid-repellent film 40 before using the liquid-repellent film 40, that is, before bringing the liquid-repellent film 40 into contact with the liquid to be repelled.

[0038] The larger the ratio Rm2, the shorter the time required for crosslinking to progress to a level at which deterioration of the coating 42 is suitably suppressed. In order to practically and appropriately shorten the time required for use of the liquid-repellent film 40, the ratio Rm2 is preferably 5 mol % or more, and more preferably 8 mol % or more. Furthermore, in order to accelerate the progress of crosslinking, the alkoxy group in the alkoxysilyl group of the second monomer is preferably a methoxy group.

[0039] Next, we will explain the configuration of the hydrophilic fine particles 41. In order to increase the reactivity with the copolymer based on an alkoxysilyl group, the hydrophilic fine particles 41 are preferably silica particles or titanium oxide particles, and more preferably silica particles.

[0040] The BET specific surface area of ​​the first hydrophilic fine particles 41 is 15 m 2 The BET specific surface area of ​​the first hydrophilic fine particles 41 is 300 m / g or more. 2 / g or less. The average primary particle diameter of the first hydrophilic microparticles 41 is preferably 10 nm or more and 100 nm or less, and more preferably 20 nm or more and 100 nm or less. If the BET specific surface area and the average primary particle diameter are within the above ranges, fine irregularities are suitably formed on the surface of the liquid-repellent film 40, thereby improving the liquid repellency.

[0041] Examples of products that can be used as the first hydrophilic fine particles 41 include the Aerosil series and Aeroxide series manufactured by Nippon Aerosil Co., Ltd., and the HDK series manufactured by Wacker Asahi Kasei Silicone Co., Ltd.

[0042] The second hydrophilic microparticles 41 preferably have an average particle diameter of 1 μm or more and 10 μm or less. When the liquid-repellent film 40 contains the first hydrophilic microparticles 41 and the second hydrophilic microparticles 41, the ratio of the total weight of the first hydrophilic microparticles 41 to the total weight of the second hydrophilic microparticles 41 contained in the liquid-repellent film 40 is preferably 0.05 or more and 0.5 or less.

[0043] When the average particle size of the second hydrophilic microparticles 41 and the ratio of the total weight of the second hydrophilic microparticles 41 to the first hydrophilic microparticles 41 are within the above ranges, unevenness consisting of the first hydrophilic microparticles 41 and the second hydrophilic microparticles 41 is suitably formed on the surface of the liquid-repellent film 40. As a result, the liquid repellency is improved.

[0044] Examples of products that can be used as the second hydrophilic fine particles 41 include the Sylysia series manufactured by Fuji Silysia Ltd., the Nipsil series manufactured by Tosoh Corporation, and Sunlovely manufactured by AGC Si-Tech Co., Ltd.

[0045] When the total weight of the methacrylate copolymer contained in the liquid-repellent film 40 is Mp, the total weight of the first hydrophilic microparticles 41 contained in the liquid-repellent film 40 is Mf, and the average primary particle diameter of the first hydrophilic microparticles 41 is R (nm), it is preferable that the weight Mp, weight Mf, and particle diameter R satisfy the following mathematical formula (1). 9≦R×(Mp / Mf)≦35 Formula (1)

[0046] When the value of R×(Mp / Mf) is within the above range, the ratio of the microparticles to the copolymer in the liquid-repellent film 40 is suitable, taking into account the particle size of the microparticles. For example, when the value of R×(Mp / Mf) is 35 or less, the amount of the methacrylate copolymer does not become too large relative to the amount of the first hydrophilic microparticles 41, and therefore, unevenness caused by the connection of the hydrophilic microparticles 41 is prevented from being leveled by the covering portion 42.

[0047] Furthermore, since the value of R×(Mp / Mf) is 9 or more, the amount of the methacrylate copolymer is not too small relative to the amount of the first hydrophilic microparticles 41, so that the first hydrophilic microparticles 41 are easily covered with the covering portions 42, and the covering portions 42 are easily formed along the irregularities caused by the chain of hydrophilic microparticles 41. Furthermore, since the particle diameter R of the first hydrophilic microparticles 41 is prevented from becoming excessively small, the specific surface area of ​​the first hydrophilic microparticles 41 is prevented from becoming excessively large, and as a result, an increase in the amount of copolymer required to cover the hydrophilic microparticles 41 is prevented.

[0048] When the adhesive layer 30 contains the large diameter fine particles 31, the average primary particle diameter of the large diameter fine particles 31 is preferably 1 μm or more and 10 μm or less. Examples of products that can be used as the large diameter particles 31 include Sunsphere manufactured by AGC Si-Tech Co., Ltd., Silicone Powder KMP series manufactured by Shin-Etsu Silicone Co., Ltd., Ganz Pearl manufactured by Aica Kogyo Co., Ltd., and Art Pearl manufactured by Negami Chemical Industries, Ltd.

[0049] In addition, products that can be used as the adhesive resin contained in the adhesive layer 30 include Auroren manufactured by Nippon Paper Industries Co., Ltd., Zaixen and Sepolsion manufactured by Sumitomo Seika Chemicals Co., Ltd., Unistall manufactured by Mitsui Chemicals, Inc., and Arrowbase manufactured by Unitika Ltd.

[0050] Regarding the surface roughness of the liquid-repellent film 40, the arithmetic mean height Sa of the surface of the liquid-repellent film 40 is preferably 1.2 μm or more. The arithmetic mean height Sa is measured in accordance with ISO 25178. For example, using a laser microscope, the arithmetic mean height Sa is measured for a square area on the surface of the liquid-repellent film 40, each of which has a side length of 650 μm. If the arithmetic mean height Sa of the surface of the liquid-repellent film 40 is 1.2 μm or more, the surface of the liquid-repellent film 40 has sufficient irregularities, so that liquid repellency can be suitably obtained.

[0051] Furthermore, the sliding angle of the liquid-repellent film 40 in a 50% by mass ethanol aqueous solution after an immersion test in an ethanol aqueous solution is preferably 25° or less. In the immersion test, the liquid-repellent film 40 is immersed in a 50% by mass ethanol aqueous solution for 72 hours, and then the liquid-repellent film 40 is pulled out of the ethanol aqueous solution and allowed to air dry for 48 hours. If the sliding angle after the immersion test is 25° or less, the deterioration of the liquid-repellent properties of the liquid-repellent film 40 due to immersion in the ethanol aqueous solution is suitably suppressed, and good liquid-repellent properties are maintained before and after immersion in the ethanol aqueous solution.

[0052] [Evaluation of deterioration of coating] The inventors of the present application used XPS (X-ray photoelectron spectroscopy) analysis to evaluate the degree of alteration of the coating portion of a liquid-repellent film before and after immersion in an ethanol aqueous solution. Specifically, the ratio of fluorine to the major elements other than oxygen in the hydrophilic fine particles was defined as the element ratio Re, and the retention rate Rk of the element ratio Re of the liquid-repellent film before and after immersion in the ethanol aqueous solution was calculated. When the hydrophilic fine particles are silica particles, the element ratio Re is the ratio of the F atom concentration to the Si atom concentration. When the hydrophilic fine particles are titanium oxide particles, the element ratio Re is the ratio of the F atom concentration to the Ti atom concentration.

[0053] The inventors of the present application then analyzed the relationship between the deterioration of the coating and the change in liquid repellency for four types of test examples, the results of which will be described in detail below. The four test examples differ in the composition of the methacrylate copolymer that is the material of the covering portion. The following chemical formula (1) shows the methacrylate copolymer of Test Example 1. The methacrylate copolymer of Test Example 1 is a copolymer of 2-(perfluorohexyl)ethyl methacrylate, 2-hydroxyethyl methacrylate, 2-(diethylamino)ethyl methacrylate, and triethylene glycol dimethacrylate. In chemical formula (1), l, m, n, and o each independently represent an integer of 1 or greater. The proportion Rm1 of the structural units derived from the first monomer in the copolymer of Test Example 1 is 50 mol % or less. [ka]

[0054] The following chemical formula (2) shows the methacrylate copolymer of Test Example 2. The methacrylate copolymer of Test Example 2 is a copolymer of 2-(perfluorohexyl)ethyl methacrylate and 2-hydroxyethyl methacrylate. In chemical formula (2), l and m each independently represent an integer of 1 or greater. The proportion Rm1 of the constitutional units derived from the first monomer in the copolymer of Test Example 2 is 93 mol%. [ka]

[0055] The following chemical formula (3) shows the methacrylate copolymer of Test Example 3. The methacrylate copolymer of Test Example 3 is a copolymer of 2-(perfluorohexyl)ethyl methacrylate and 2-(diethylamino)ethyl methacrylate. In chemical formula (3), l and m each independently represent an integer of 1 or greater. The proportion Rm1 of the constitutional units derived from the first monomer in the copolymer of Test Example 3 is 93 mol%. [ka]

[0056] The following chemical formula (4) shows the methacrylate copolymer of Test Example 4. The methacrylate copolymer of Test Example 4 is a copolymer of 2-(perfluorohexyl)ethyl methacrylate and 3-methacryloxypropyltrimethoxysilane. In chemical formula (4), l and m each independently represent an integer of 1 or greater.

[0057] Test Example 4 corresponds to the liquid-repellent film 40 of this embodiment. For example, in a copolymer represented by the following chemical formula (4), if the total number of constitutional units derived from the first monomer is l and the total number of constitutional units derived from the second monomer is m, the ratio Rm1 is expressed as l / (l+m) and the ratio Rm2 is expressed as m / (l+m). The ratio Rm1 in the copolymer of Test Example 4 was 93 mol %, and the ratio Rm2 was 7 mol %. [ka]

[0058] For each of Test Examples 1 to 4, three types of liquid-repellent film samples were prepared with weight ratios of 0.30, 0.65, and 1.00 by changing the weight ratio of the methacrylate copolymer to the hydrophilic particles. The weight ratio is the ratio of the weight Mp of the methacrylate copolymer to the weight Mf of the first hydrophilic particles 41. For each sample, the liquid repellency and the retention rate Rk of the element ratio Re were determined before and after immersion of the liquid-repellent film in an ethanol aqueous solution. The hydrophilic particles were silica particles (Aerosil 50 manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 30 nm, BET specific surface area 50 m 2 / g).

[0059] The method for measuring the liquid repellency and the retention rate Rk of the element ratio Re is shown below. <Liquid repellency> The sliding angles of 10 different concentrations of ethanol aqueous solutions were measured for a liquid-repellent film that had not been immersed in an ethanol aqueous solution and for a liquid-repellent film that had been immersed in an ethanol aqueous solution. The concentrations of the ethanol aqueous solutions tested were 0 mass%, 10 mass%, 20 mass%, 30 mass%, 40 mass%, 50 mass%, 60 mass%, 70 mass%, 80 mass%, and 90 mass%. The surface tension of aqueous ethanol solutions of various concentrations at 20°C was measured using the Wilhelmy method, and the results are shown below. Concentration 90% by mass: Surface tension 23.2mN / m Concentration 80% by mass: Surface tension 24.3mN / m Concentration 70% by mass: Surface tension 25.5mN / m Concentration 60% by mass: Surface tension 26.7mN / m Concentration 50% by mass: Surface tension 28.5mN / m Concentration 40% by mass: Surface tension 30.7mN / m Concentration 30% by mass: Surface tension 33.5mN / m Concentration 20% by mass: Surface tension 38.6mN / m

[0060] In the immersion test, a liquid-repellent film cut into a square shape with sides of 5 cm was immersed in a 50% by mass aqueous ethanol solution in a glass container for 72 hours, then removed from the ethanol solution and allowed to air-dry for 48 hours.

[0061] The sliding angle was determined by dropping a 50 μL droplet of ethanol water solution onto the surface of a horizontally placed liquid-repellent film, gradually tilting the film, and measuring the tilt angle of the liquid-repellent film when the droplet began to move without stopping. When the sliding angle was 25° or less, the aqueous ethanol solution at the concentration at which the sliding angle was obtained was deemed to be liquid-repellent.

[0062] <Maintenance rate Rk of element ratio Re> The atomic concentration was measured on the surface of the liquid-repellent film using an X-ray electron spectrometer (JPS-9030, manufactured by JEOL Ltd.). α (1253.6 eV) and the X-ray output was 100 W (10 kV-10 mA). 1s , F1s , O 1s , Si 2p The peak area was corrected using a predetermined relative sensitivity ratio to determine the F atom concentration (atomic %) and Si atom concentration (atomic %) on the assumption that the liquid-repellent film is composed of C, F, O, and Si.

[0063] The F atom concentration and Si atom concentration were measured for the liquid-repellent film that had not been immersed in the ethanol aqueous solution, and the value obtained by dividing the F atom concentration by the Si atom concentration was taken as the initial element ratio Re, i.e., before immersion. Furthermore, the F atom concentration and Si atom concentration were measured for the liquid-repellent film after the immersion test, and the value obtained by dividing the F atom concentration by the Si atom concentration was taken as the element ratio Re after immersion. The immersion test was carried out in the same manner as the immersion test described above in the liquid repellency measurement method. The value of the element ratio Re after immersion relative to the element ratio Re before immersion was calculated, and this value was taken as the retention rate Rk.

[0064] 3 shows the measurement results of the liquid repellency before and after immersion and the retention rate Rk of the element ratio Re for Test Examples 1 to 4. The liquid repellency is shown as the concentration of the ethanol aqueous solution that allows liquid repellency.

[0065] As shown in Figure 3, Test Example 1 had poor initial liquid repellency compared to the other Test Examples. This is thought to be because the methacrylate copolymer of Test Example 1 had a high proportion of structural units derived from hydrophilic monomers and a low proportion of structural units derived from the first monomer having a perfluoroalkyl group. Furthermore, in Test Example 1, the liquid repellency after immersion was significantly lower than the initial liquid repellency. Furthermore, in Test Example 1, the retention rate Rk of the element ratio Re was only about 0.55 to 0.70.

[0066] In Test Example 2, although the initial liquid repellency was high, the liquid repellency decreased significantly after immersion and was almost completely lost. In Test Example 2, the retention rate Rk of the element ratio Re was a low value of about 0.35 to 0.50. In Test Example 3, the liquid repellency after immersion is also significantly lower than the initial liquid repellency, and the retention rate Rk of the element ratio Re is only about 0.45 to 0.65.

[0067] In contrast, Test Example 4 had high initial liquid repellency and showed less deterioration in liquid repellency after immersion than the other Test Examples. In Test Examples 1 to 3, the concentration of ethanol aqueous solution that was liquid repellent after immersion was only about 0% to 20% by mass, but Test Example 4 was still able to repel an ethanol aqueous solution with a concentration of 70% by mass even after immersion. Furthermore, Test Example 4 achieved a high retention rate Rk of the element ratio Re of 0.90 or more.

[0068] These results confirm that the higher the element ratio Re retention rate Rk, the smaller the decrease in liquid repellency of the liquid-repellent film due to immersion in an ethanol aqueous solution. In other words, if the element ratio Re retention rate Rk is 0.8 or higher, the decrease in liquid repellency can be suitably suppressed.

[0069] The lower the retention rate Rk of the element ratio Re, the more fluorine in the liquid-repellent film is reduced by immersion, i.e., the greater the alteration of the coating portion, suggesting that the alteration of the coating portion is the cause of the decrease in liquid repellency. Furthermore, as in Test Example 4, it is suggested that the alteration of the coating portion is suppressed by the methacrylate copolymer containing a structural unit derived from a second monomer having an alkoxysilyl group, and as a result, high liquid repellency can be maintained before and after immersion.

[0070] In Test Example 4, the coating also contains Si, but the number of Si atoms relative to the number of F atoms in the coating is minute, so the presence of Si atoms in the coating does not affect the overall analysis results.

[0071] [Method of manufacturing liquid-repellent film] The methacrylate copolymer can be obtained by polymerizing the monomers using a known polymerization method. For example, a solution is prepared by adding the monomers and polymerization initiator to the solvent using 1,3-bis(trifluoromethyl)benzene as the solvent and 2,2'-azobis(isobutyrate)dimethyl as the polymerization initiator, so that the monomer concentration is 40% by mass and the polymerization initiator concentration is 0.2% by mass. The solution is then stirred for 24 hours under an argon gas atmosphere at 70°C to obtain the methacrylate copolymer.

[0072] A method for manufacturing the liquid-repellent film 40 and the liquid-repellent article 10 will now be described. First, a coating liquid in which the material for the adhesive layer 30 is dissolved or dispersed is applied to the surface of the support 20, and the formed film is dried to form the adhesive layer 30. The coating liquid can be applied by any known coating method, such as bar coating, spraying, gravure coating, or die coating.

[0073] Next, a coating liquid in which the material of the liquid-repellent film 40 is dissolved or dispersed is applied to the surface of the adhesive layer 30, and the formed film is dried to form the liquid-repellent film 40. The coating liquid can be applied by any known coating method, such as bar coating, spraying, gravure coating, or die coating.

[0074] The coating liquid for forming the liquid-repellent film 40 can be obtained, for example, by mixing a dispersion liquid in which hydrophilic microparticles 41 are dispersed with a solution in which a methacrylate copolymer is dissolved. The dispersion medium of the dispersion liquid is not particularly limited as long as it can disperse the hydrophilic microparticles 41, and the solvent of the solution is not particularly limited as long as it can dissolve the methacrylate copolymer.

[0075] However, from the viewpoint of enhancing the liquid repellency of the liquid-repellent film 40, it is preferable that the polarity of the coating liquid medium containing the dispersion medium and solvent is low, since this facilitates coating of the hydrophilic particles 41 with the methacrylate copolymer. Specifically, the dispersion medium in the dispersion of the hydrophilic particles 41 is preferably ethyl acetate, propyl acetate, or methyl ethyl ketone, and the solvent for the solution of the methacrylate copolymer is preferably 1,3-bis(trifluoromethyl)benzene. Furthermore, in order to keep the polarity of the coating liquid low, it is preferable to prepare the coating liquid so that the weight of the solvent contained in the coating liquid is greater than the weight of the dispersion medium.

[0076] For example, the methacrylate copolymer is preferably soluble or dispersible at a concentration of 5% by mass or more in a solvent obtained by mixing ethyl acetate and 1,3-bis(trifluoromethyl)benzene in a weight ratio of 3:7.

[0077] If the methacrylate copolymer has solubility or dispersibility in the mixed solvent, the mixed solvent can be used as the solvent for the coating liquid used to form the liquid-repellent film 40. By using the mixed solvent as the solvent for the coating liquid, a liquid-repellent film 40 with high liquid repellency can be obtained. According to the above manufacturing method, a liquid-repellent film 40 having high liquid repellency can be obtained without going through a complicated process or a costly process such as a process of bonding the fine particles and the copolymer.

[0078] The liquid-repellent film 40 can effectively prevent high-viscosity, low-surface-tension liquids from adhering to its surface. Examples of such liquids include surfactant-containing aqueous solutions, hydrocarbon oils, silicone oils, and organic solvent-containing liquids. Liquids that can be repelled by the liquid-repellent film 40 are not limited to everyday items, but can also be industrial liquids such as paints, fuels, lubricants, adhesives, conductive pastes, liquid rubber, caulking agents, and asphalt. Furthermore, the liquid-repellent film 40 can repel any liquid that is desired to be prevented from adhering to the surface of an article, such as a container, including liquids containing pharmaceuticals, pesticides, or toxic substances, such as ethanol aqueous solutions, as long as it is not limited to high-viscosity, low-surface-tension liquids.

[0079] The use of liquid-repellent film 40 on the inner surface of the liquid container prevents the liquid from remaining inside the container when the liquid is removed from the container. As a result, a decrease in the efficiency of removing the liquid is prevented, the burden required for cleaning the areas where the liquid is attached can be reduced, and deterioration of sanitary conditions, such as bacterial growth, caused by remaining liquid is also prevented.

[0080] The liquid-repellent film 40 of this embodiment can prevent a decrease in liquid repellency due to contact with liquid, and therefore when used in a liquid container, the above-mentioned effects are preferably exhibited even after the container has contained the liquid for a long period of time. In particular, by using the liquid-repellent film 40 in a container for a liquid containing ethanol and water, the effect of preventing a decrease in liquid repellency can be significantly achieved.

[0081] [Example] The liquid-repellent film and the liquid-repellent article described above will be explained using specific examples and comparative examples. (Production of methacrylate copolymer) Eight types of methacrylate copolymers shown in Table 1 were produced and their solubility in solvents was evaluated. Table 1 shows the ratio of the monomers used to produce the copolymers and the solubility evaluation results. Each copolymer is a random copolymer.

[0082] [Table 1] The abbreviations in Table 1 correspond to the following monomers: RfMA: 2-(perfluorohexyl)ethyl methacrylate HEMA: 2-hydroxyethyl methacrylate TMSPMA: 3-methacryloxypropyltrimethoxysilane The method for producing the copolymer and the method for evaluating the solubility are as follows.

[0083] <Method of producing copolymer> A solution was prepared by adding 1,3-bis(trifluoromethyl)benzene as a solvent and 2,2'-azobis(isobutyrate)dimethyl as a polymerization initiator to the solvent so that the monomer concentration was 40% by mass and the polymerization initiator concentration was 0.2% by mass. The solution was then stirred for 24 hours under an argon gas atmosphere at 70°C to produce a methacrylate copolymer.

[0084] <Method for evaluating solubility> 0.5 g of the copolymer was added to a mixed solution of 3 g of ethyl acetate and 7 g of 1,3-bis(trifluoromethyl)benzene, and the mixture was placed in an environment of 20° C. When the entire amount of the copolymer dissolved in the solution, the solubility was deemed good and evaluated as "Good", and when at least a part of the copolymer did not dissolve, the solubility was deemed poor and evaluated as "Poor".

[0085] As shown in Table 1, polymer P1, in which the proportion of the first monomer having a perfluoroalkyl group was 100 mol%, and polymer P6, in which the proportion of the second monomer having an alkoxysilyl group was 15 mol%, among the monomers used to produce the copolymer, did not exhibit sufficient solubility in the solvent. On the other hand, polymers P2, P3, P4, and P5, in which the proportion of the first monomer was 80 mol% to 98 mol% and the proportion of the second monomer was 2 mol% to 13 mol%, exhibited good solubility. Furthermore, polymers P7 and P8, which did not contain a second monomer but contained a hydrophilic third monomer, also exhibited good solubility.

[0086] (liquid-repellent film material) The materials used to form the liquid-repellent films in the examples and comparative examples, and the methods for preparing the coating liquids for forming the adhesive layer and liquid-repellent film are described below. <Support> Polyethylene terephthalate film (thickness 50 μm)

[0087] <Coating liquid for adhesive layer formation> The following two types of coating liquids for forming adhesive layers were prepared.

[0088] Adhesive layer A1: A polyolefin resin (Arrowbase SB5230N (solid content 50%) manufactured by Unitika Ltd.) was used as the adhesive resin, and 6.7 g of the adhesive resin was dissolved in a mixed solvent of 10.0 g of water and 50.0 g of isopropanol to prepare a coating liquid for forming the adhesive layer. The solid content in the coating liquid was 3.3 mass %.

[0089] Adhesive layer A2: A polyolefin resin (Arrowbase SB5230N, manufactured by Unitika Ltd., solid content 50%) was used as the adhesive resin, and acrylic resin particles (Art Pearl SE-010T, manufactured by Negami Chemical Industrial Co., Ltd., average primary particle diameter 10 μm) were used as the large-diameter particles. 6.7 g of adhesive resin and 2.9 g of large-diameter particles were mixed with a mixed solvent of 40.5 g of water and 50.0 g of isopropanol to prepare a coating liquid for forming an adhesive layer. The solid content of the coating liquid was 20.0 mass %.

[0090] <Coating liquid for forming liquid-repellent film> Hydrophilic particles were mixed into ethyl acetate at a concentration of 8% by mass, and the mixture was stirred using a magnetic stirrer to prepare a particle dispersion.

[0091] The following four types of hydrophilic particles were used. New aqueous microparticles F1: Silica particles (Aerosil 50 manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 30 nm, BET specific surface area 50 m 2 / g) Hydrophilic particles F2: Silica particles (Aerosil 90 manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 20 nm, BET specific surface area 90 m 2 / g) Hydrophilic microparticles F3: Silica particles (Aerosil 200 manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 12 nm, BET specific surface area 200 m 2 / g) Hydrophilic microparticles F4: Titanium oxide particles (Aeroxide P25 manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter 20 nm, BET specific surface area 50 m 2 / g) A polymer solution was prepared by dissolving methacrylate copolymers in 1,3-bis(trifluoromethyl)benzene at a concentration of 2% by mass. The methacrylate copolymers used were the six polymers P2, P3, P4, P5, P7, and P8 mentioned above. Polymers P1 and P6 were not used due to their poor solubility in the solvent.

[0092] The fine particle dispersion and the polymer solution were mixed and stirred using a magnetic stirrer to prepare a coating solution for forming a liquid-repellent film. 1,3-bis(trifluoromethyl)benzene or ethyl acetate was added as a dilution solvent as needed so that the solid content in the coating solution was 3 mass % and the weight ratio of 1,3-bis(trifluoromethyl)benzene to ethyl acetate was 7:3.

[0093] (Method of manufacturing liquid-repellent film) The adhesive layer-forming coating liquid was applied to the surface of the support using a wire bar, and the resulting film was dried under hot air at 100°C for 90 seconds to form an adhesive layer. The amount of the adhesive layer-forming coating liquid applied was approximately 1 g / m. 2 is.

[0094] Next, a liquid-repellent coating solution was applied to the surface of the adhesive layer using a wire bar, and the resulting film was dried under hot air at 100°C for 90 seconds to form a liquid-repellent film. The amount of the liquid-repellent coating solution applied was approximately 1 g / m. 2 is.

[0095] (Configurations of Examples and Comparative Examples) Using the above-mentioned materials and manufacturing method, the combinations of adhesive layers, hydrophilic particles, and methacrylate copolymers, and the ratios of hydrophilic particles to methacrylate copolymers were changed to obtain Examples 1 to 16 and Comparative Examples 1 to 4. Table 2 shows the type of copolymer, hydrophilic particles, and adhesive layer, the value of R×(Mp / Mf), and the arithmetic mean height Sa for each Example and Comparative Example.

[0096] [Table 2]

[0097] The arithmetic mean height Sa of the liquid-repellent film was measured using a confocal laser microscope (OLS-4100, manufactured by Olympus Corporation) over a square area measuring 650 μm on a side on the surface of the liquid-repellent film. The magnification of the lens used was 50x. Prior to the measurement, the liquid-repellent film may be subjected to platinum sputtering for 100 seconds.

[0098] (Liquid repellency evaluation) For each example and comparative example, the liquid repellency retention performance over time and the change in liquid repellency when immersed in liquid were evaluated. The evaluation method is described below. In addition, the retention rate Rk of the element ratio Re was calculated for each example and comparative example.

[0099] <Evaluation of liquid repellency maintenance performance> For each example and comparative example, after forming a liquid-repellent film on the support, the liquid-repellent film was placed in an environment of 25°C and a relative humidity of 50%, and test pieces were prepared after 1 day, 3 days, and 10 days. The test pieces were shaped like a square with each side measuring 5 cm.

[0100] The sliding angle of each test piece in a 50% by mass aqueous ethanol solution was measured before and after the immersion test. In the immersion test, the test piece was immersed in a 50% by mass aqueous ethanol solution in a glass container for 72 hours, then removed from the ethanol solution and air-dried for 48 hours.

[0101] The sliding angle was determined by dropping a 50 μL droplet of ethanol water solution onto the surface of a horizontally placed liquid-repellent film, gradually tilting the film, and measuring the tilt angle of the liquid-repellent film when the droplet began to move without stopping. Regarding liquid repellency, a sliding angle of 25° or less was rated as "○", a sliding angle of more than 25° but less than 50° was rated as "△", and a sliding angle of more than 50° was rated as "×".

[0102] <Evaluation of changes in liquid repellency> For each example and comparative example, after forming a liquid-repellent film on the support, the liquid-repellent film was placed in an environment of 25°C and a relative humidity of 50% for 10 days, and then a test piece was prepared by cutting the liquid-repellent film into a square with a side length of 5 cm.

[0103] The liquid to be repellent, shampoo (Kumano Oil & Fat Co., Ltd., Seven Premium Lifestyle Plant-Based Shampoo, Gentle on Hair), was poured into a glass container to a depth of 4.5 cm, and the test piece was immersed in the liquid. The surface tension of this shampoo at 20°C was measured using the pendant drop method and found to be 27.3 mN / m.

[0104] The state of liquid on the surface of the test piece was observed when it was pulled out of the liquid 3 hours, 1 day, and 7 days after the start of immersion. A case where no liquid was observed on the surface of the test piece immediately after pulling it out was marked "○", a case where liquid was observed on the surface of the test piece immediately after pulling it out but the liquid slid off the surface within 60 seconds after pulling it out was marked "△", and a case where a film-like liquid was observed on the surface of the test piece 60 seconds after pulling it out was marked "×".

[0105] <Maintenance rate Rk of element ratio Re> For each example and comparative example, after forming a liquid-repellent film on a support, the liquid-repellent film was placed in an environment of 25°C and 50% relative humidity for 10 days. Then, the retention rate Rk of the element ratio Re was calculated using the method described in the above embodiment. A retention rate Rk of 0.8 or more was marked "Good," and a retention rate Rk of less than 0.8 was marked "Poor."

[0106] <Evaluation results> Table 3 shows the results of each evaluation and the retention rate Rk of the element ratio Re for each example and each comparative example.

[0107] [Table 3]

[0108] As shown in Table 3, the greater the proportion of the second monomer in the monomers used to produce the methacrylate copolymer, the earlier the effect of suppressing the decrease in liquid repellency after the formation of the liquid-repellent film. Specifically, in Examples 5, 6, and 9 to 16, which used polymers P4 and P5, each containing 8 mol % or more of the second monomer, the effect of suppressing the decrease in liquid repellency in the immersion test was observed one day after the formation of the liquid-repellent film. On the other hand, in Example 4, which used polymer P3, each containing 5 mol % of the second monomer, the effect of suppressing the decrease in liquid repellency was not observed one day after the formation of the liquid-repellent film, but the effect was observed three days after the formation of the liquid-repellent film. Furthermore, in Examples 1 to 3, 7, and 8, which used polymer P2, each containing 3 mol % of the second monomer, the effect of suppressing the decrease in liquid repellency was not observed one day or three days after the formation of the liquid-repellent film, but the effect was not observed until 10 days after the formation of the liquid-repellent film.

[0109] Therefore, in order to achieve the effect of suppressing the decrease in liquid repellency in a shorter period of time, it is suggested that the ratio Rm2 of the structural units derived from the second monomer in the copolymer is preferably 5 mol% or more, and more preferably 8 mol% or more. In Comparative Examples 1 to 4, which used polymers P7 and P8 that did not contain the second monomer, the decrease in liquid repellency was not suppressed even after 10 days had passed since the formation of the liquid repellent film.

[0110] In the evaluation of the liquid repellency of the shampoo, after 3 hours from the start of immersion, good liquid repellency was obtained in all of Examples 1 to 16 and Comparative Examples 1 to 4. On the other hand, after 1 day from the start of immersion, good liquid repellency was maintained in Examples 1 to 16, but a decrease in liquid repellency was confirmed in Comparative Examples 1 to 4. After 7 days from the start of immersion, the liquid repellency further decreased in Comparative Examples 1 to 4, whereas in Examples 1 to 16 good liquid repellency was maintained or the decrease in liquid repellency was kept smaller than in the comparative examples.

[0111] In Examples 1 to 16, the element ratio Re retention rate Rk was as high as 0.8 or more, whereas in Comparative Examples 1 to 4, the element ratio Re retention rate Rk was lower than 0.8.

[0112] Therefore, it was confirmed that the methacrylate copolymer containing structural units derived from the second monomer prevents the coating from deteriorating, and as a result, it is possible to prevent the decrease in liquid repellency due to contact with liquid.

[0113] Furthermore, in the evaluation of the liquid repellency of shampoo, a comparison of the results after 7 days from the start of immersion for Examples 1 to 16 suggests that high liquid repellency can be easily obtained for a longer period of time when the value of R×(Mp / Mf) is 9 or more and 35 or less, the average primary particle diameter of the hydrophilic microparticles is 20 nm or more, and the arithmetic mean height Sa is 1.2 μm or more.

[0114] As described above in the embodiments and examples, the liquid-repellent film 40 can provide the following effects. (1) In the methacrylate copolymer contained in the coating portion 42, the ratio of structural units derived from a first monomer having a perfluoroalkyl group is 80 mol % or more and 98 mol % or less, and the ratio of structural units derived from a second monomer having an alkoxysilyl group is 2 mol % or more and 13 mol % or less. According to this configuration, covalent bonds are formed between polymer chains or between polymer chains and the surfaces of the hydrophilic microparticles 41 based on the alkoxysilyl groups. The progress of this reaction prevents alteration of the coating portion 42, such as elution or non-uniformity, when the liquid-repellent film 40 is in contact with a liquid to be liquid-repellent. Therefore, a decrease in the liquid-repellent properties of the liquid-repellent film 40 is prevented.

[0115] (2) When the hydrophilic fine particles 41 are silica particles or titanium oxide particles, the reactivity between the copolymer and the hydrophilic fine particles 41 is enhanced, and therefore, the alteration of the coating portion 42 is more suitably suppressed.

[0116] (3) When the second monomer is any one of 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane, the reaction based on the alkoxysilyl group described above proceeds favorably, and the monomer is easily available.

[0117] (4) Since the retention rate Rk of the element ratio Re is 0.8 or more, deterioration of the coating 42 due to immersion in an ethanol aqueous solution is effectively prevented. Therefore, deterioration of the liquid repellency of the liquid-repellent film 40 is effectively prevented.

[0118] (5) The weight Mp of the methacrylate copolymer, the weight Mf of the first hydrophilic microparticles 41, and the average primary particle diameter R (nm) of the first hydrophilic microparticles 41 satisfy 9≦R×(Mp / Mf)≦35. This configuration ensures that the ratio of microparticles to copolymer in the liquid-repellent film 40 is optimal, taking into account the particle diameter of the microparticles. This prevents the amount of copolymer from being too large or too small relative to the hydrophilic microparticles 41, and prevents the specific surface area of ​​the hydrophilic microparticles 41 from becoming excessively large. This facilitates the proper formation of the coating 42 that conforms to the irregularities caused by the chains of hydrophilic microparticles 41, thereby making it easier to achieve higher water repellency.

[0119] (6) When the average primary particle diameter of the first hydrophilic fine particles 41 is 20 nm or more, the unevenness on the surface of the liquid-repellent film 40 can be easily formed to a size suitable for liquid repellency, which makes it easier to obtain higher liquid repellency.

[0120] (7) If the arithmetic mean height Sa of the surface of the liquid-repellent film 40 is 1.2 μm or more, the surface of the liquid-repellent film 40 has unevenness of sufficient height, making it easier to obtain higher liquid repellency. (8) If the liquid-repellent film 40 after the immersion test in an ethanol aqueous solution has a sliding angle of 25° or less in an ethanol aqueous solution with a concentration of 50% by mass, the deterioration of the liquid-repellent properties of the liquid-repellent film 40 due to immersion in the ethanol aqueous solution is suitably suppressed. [Explanation of symbols]

[0121] 10…Liquid repellent article 20...Support 30…adhesive layer 31...Large particle 40…Liquid repellent film 41…Hydrophilic fine particles 42...Covering part

Claims

1. A liquid-repellent membrane having hydrophilic fine particles and a coating portion that covers the hydrophilic fine particles, The BET specific surface area of ​​the hydrophilic fine particles is 15 m ２ / g or more, the average primary particle diameter of the hydrophilic fine particles is 20 nm or more; the covering portion includes a methacrylate copolymer, the methacrylate copolymer is a copolymer of a plurality of types of monomers including a first monomer which is a methacrylate monomer having a perfluoroalkyl group and a second monomer which is a methacrylate monomer having an alkoxysilyl group; a ratio of the constitutional unit derived from the first monomer in the methacrylate copolymer is 80 mol% or more and 98 mol% or less, a ratio of the constitutional unit derived from the second monomer in the methacrylate copolymer is 2 mol% or more and 13 mol% or less; When the total weight of the methacrylate copolymer contained in the liquid-repellent film is Mp, the total weight of the hydrophilic fine particles contained in the liquid-repellent film is Mf, and the average primary particle diameter of the hydrophilic fine particles is R (nm), the weight Mp, the weight Mf, and the particle diameter R satisfy the following mathematical formula (1): 9≦R×(Mp / Mf)≦35 Formula (1) The arithmetic mean height Sa of the surface of the liquid-repellent film is 1.2 μm or more. Liquid repellent film.

2. The hydrophilic particles are silica particles or titanium oxide particles. The liquid-repellent film according to claim 1 .

3. The second monomer is any one of 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane. The liquid-repellent film according to claim 1 or 2.

4. the hydrophilic fine particles are silica particles, the ratio of the F atom concentration to the Si atom concentration in the liquid-repellent film is an element ratio; The immersion test is a test in which the liquid-repellent film is immersed in an aqueous ethanol solution having a concentration of 50% by mass for 72 hours. The ratio of the element ratio of the liquid-repellent film after the immersion test to the element ratio of the liquid-repellent film before the immersion test is 0.8 or more. The liquid-repellent film according to any one of claims 1 to 3.

5. the hydrophilic fine particles are titanium oxide particles, the ratio of the F atom concentration to the Ti atom concentration in the liquid-repellent film is an element ratio; The immersion test is a test in which the liquid-repellent film is immersed in an aqueous ethanol solution having a concentration of 50% by mass for 72 hours. The ratio of the element ratio of the liquid-repellent film after the immersion test to the element ratio of the liquid-repellent film before the immersion test is 0.8 or more. The liquid-repellent film according to any one of claims 1 to 3.

6. The immersion test is a test in which the liquid-repellent film is immersed in an aqueous ethanol solution having a concentration of 50% by mass for 72 hours. After the immersion test, the liquid-repellent film has a sliding angle of 25° or less for an aqueous ethanol solution having a concentration of 50% by mass. The liquid-repellent film according to any one of claims 1 to 5.

7. A liquid-repellent film according to any one of claims 1 to 6, A support; an adhesive layer located between the liquid-repellent film and the support; The adhesive layer contains fine particles having an average primary particle size larger than that of the hydrophilic fine particles. Liquid repellent articles.

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