A hydrophilic water-repellent treatment agent, a surface treatment method using the hydrophilic water-repellent treatment agent, and a substrate on which a hydrophilic water-repellent film is formed.

Abstract

To provide a hydrophilic lubricating water treatment agent for forming a membrane that can combine higher hydrophilicity and water slipping property and has excellent hydrolytic stability.SOLUTION: A hydrophilic lubricating water treatment agent for forming a hydrophilic slip water membrane containing, in at least one silicone atom, an organosilicon compound (A) in which at least one hydrophilic chain-containing group and at least one hydrolyzable group are bonded, and a metal alkoxide (B), further a hydrophilic lubricating water treatment agent that contains silicone oil (C) having a hydrophilic chain-containing group and a molecular weight of 1000 or less, or in which the organosilicon compound (A) has three alkoxy groups that are the hydrolyzable group bonded to a silicone atom at both ends.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hydrophilic water-repellent treatment agent, a surface treatment method using the hydrophilic water-repellent treatment agent, and a substrate on which a hydrophilic water-repellent film is formed. [Background technology]

[0002] There is a need for technology that can impart both hydrophilicity and hydrophobicity to the surface of a substrate. For example, in a heat exchanger using aluminum, in order to suppress noise generation caused by condensation on the fin surface, scattering of water droplets, and contamination due to mold growth, it is preferable to apply a surface treatment that has high wettability (high hydrophilicity) and allows attached water droplets to slide off and be removed quickly while they are still minute (high hydrophobicity).

[0003] Patent Document 1 describes forming a hydrophilic and hydrophobic film on a substrate using a hydrophilic and hydrophobic treatment agent containing, in a predetermined molar ratio, an organosilicon compound (A) in which at least one silicon atom is bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, and a metal alkoxide (B).

[0004] Non-patent document 1 lists a target value of 30° or less for the water contact angle between both ends of a water droplet with 2 μL of pure water dropped on it, as an indicator of the initial hydrophilicity and hydrophilicity persistence of a pre-coated fin material for air conditioners. It also lists a target value of 13° or less for the angle (fall angle) when the leading end moves 0.2 mm while a fin material with 10 μL of water dropped on it is tilted at a speed of 1° / sec. However, specific means for achieving these values ​​are not shown. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-117636 [Non-patent literature]

[0006] [Non-Patent Document 1] UACJ Technical Reports. Vol.5(2018),pp.80-83 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Patent Document 1 describes the wettability and water-repellency of a hydrophilic and water-repellent coating formed using the treatment agent described in the document, specifically the contact angle θ of a water droplet with respect to the coating, which is an indicator of hydrophilicity. S The drop angle θ is 40° or less, indicating water droplet removal capability. t However, it is stated that the tilt angle was 30° or less for a 10 μL water droplet with a tilt rate of 1° / second. However, judging from the target values ​​in Non-Patent Document 1, the hydrophilicity and hydrophobicity of the coating were still insufficient. Furthermore, hydrolysis stability is essential for hydrophilic and water-repellent coatings formed on substrates intended to come into contact with water droplets or water films. However, it has been found that hydrophilic and water-repellent coatings formed using the treatment agent described in Patent Document 1 may show increased hydrophilicity over time due to insufficient hydrolysis stability, but their water-repellent properties may deteriorate significantly.

[0008] In view of the above circumstances, the present invention aims to provide a hydrophilic and hydrophobic coating that achieves both higher hydrophilicity and hydrophobicity compared to the hydrophilic and hydrophobic coating described in Patent Document 1, and also has excellent hydrolysis stability. [Means for solving the problem]

[0009] As a result of intensive studies to solve the above problems, the present inventors have found that by mixing a hydrophilic lubricating treatment agent with an organosilicon compound and a metal alkoxide with a silicone oil having a hydrophilic chain-containing group and a molecular weight of 1000 or less, or by using a specific organosilicon compound and a metal alkoxide, it is possible to achieve both higher hydrophilicity and lubricity than conventional ones, and a hydrophilic lubricating film having excellent hydrolysis stability can be obtained, and thus the present invention has been completed.

[0010] That is, the means for solving the above problems include the following aspects. [1] An organosilicon compound (A) in which at least one hydrophilic chain-containing group and at least one hydrolyzable group are bonded to at least one silicon atom, a metal alkoxide (B), a silicone oil (C) having a molecular weight of 1000 or less represented by the following general formula (1), and a hydrophilic lubricating treatment agent containing the same.

[0011] [Chemical formula] (In the formula, R 1 represents a hydrophilic chain-containing group, R 2 each independently represents an alkyl group having 1 to 5 carbon atoms, m and n are integers, and m / n is 1 to 6.) [2] In the above formula (1), R 1 is a group represented by R 3 -O(CH2CH2O) p -CH3 (R 3 is an alkylene group having 1 to 5 carbon atoms, and p is an integer of 5 to 10), and the hydrophilic lubricating treatment agent of [1]. [3] The organosilicon compound (A) is an organosilicon compound (A1) represented by the following general formula (2), and the hydrophilic lubricating treatment agent of [1] or [2].

[0012] [Chemical formula] (In the formula, R 4R is an alkyl group having 1 to 5 carbon atoms. 5 , R 6 is an alkylene group having 1 to 5 carbon atoms, q is an integer greater than or equal to 4, and each R 5 They may be the same or different from each other, R 7 These are each an alkyl group having 1 to 5 carbon atoms. [4] An organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, Metal alkoxide (B) and, Includes, The aforementioned organosilicon compound (A) is an organosilicon compound (A2) represented by the following formula (3), which is a hydrophilic and water-repellent treatment agent.

[0013] [ka] (In the formula, each R 8 Each of these is an alkyl group having 1 to 5 carbon atoms, and each R 9 Each of these is an alkylene group with 1 to 5 carbon atoms, and R 10 is an alkylene group having 1 to 5 carbon atoms, q is an integer greater than or equal to 4, and each R 10 They may be the same or different from each other. [5] A surface treatment method comprising a hydrophilic and hydrophobic coating formation step, in which a hydrophilic and hydrophobic coating is formed by contacting one of the hydrophilic and hydrophobic treatment agents [1] to [4] onto the surface of a substrate. [6] The surface treatment method of [5] wherein the substrate is at least one selected from metal, metal oxide, silicon, glass, or resin. [7] The substrate is a fin material for a heat exchanger, and the surface treatment method of [5]. [8]On the surface, An organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, Metal alkoxide (B) and, A silicone oil (C) with a molecular weight of 1000 or less, represented by the following general formula (1), A substrate on which a hydrophilic and hydrophobic coating containing hydrolyzed and condensed polymers has been formed.

[0014] [ka] (In the formula, R 1 represents a hydrophilic chain-containing group, R 2 Each of these independently represents an alkyl group with 1 to 5 carbon atoms, where m and n are integers, and m / n is between 1 and 6. [9] In formula (1) above, R 1 R 3 -O(CH2CH2O) p -CH3(R 3 The base material of [8] is a group represented by an alkylene group having 1 to 5 carbon atoms, where p is an integer from 5 to 10.

[10] The organosilicon compound (A) is an organosilicon compound (A1) represented by the following general formula (2), which is the base material of [8] or [9].

[0015] [ka] In the formula, R 4 R is an alkyl group having 1 to 5 carbon atoms. 5 , R 6 is an alkylene group having 1 to 5 carbon atoms, q is an integer greater than or equal to 4, and each R 5 They may be the same or different from each other, R 7 These are each an alkyl group having 1 to 5 carbon atoms.

[11] On the surface, An organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, It contains a metal alkoxide (B) and a hydrolysis / condensation polymer thereof. The aforementioned organosilicon compound (A) is an organosilicon compound (A2) represented by the following formula (3), and the substrate has a hydrophilic and hydrophobic coating formed on it.

[0016] [ka] (In the formula, each R 8 Each of these is an alkyl group having 1 to 5 carbon atoms, and each R 9 Each of these is an alkylene group with 1 to 5 carbon atoms, and R 10 is an alkylene group having 1 to 5 carbon atoms, q is an integer greater than or equal to 4, and each R 10 They may be the same or different from each other.

[12] The substrate is any of the substrates in [8] to

[11] , which is at least one selected from metal, metal oxide, silicon, glass, or resin.

[13] The substrate is a fin material for a heat exchanger, which is any of the substrates from [8] to

[11] . [Effects of the Invention]

[0017] According to the present invention, a hydrophilic and hydrophobic coating can be formed on a substrate that achieves both higher hydrophilicity and hydrophobicity compared to the conventional technology, while also having excellent hydrolysis stability. [Brief explanation of the drawing]

[0018] [Figure 1] This diagram shows an example of the process for forming a hydrophilic, water-repellent coating according to this embodiment. [Figure 2] Diagram illustrating the static contact angle (θS), an index used to evaluate hydrophilicity. [Figure 3] An explanatory diagram of the sliding angle (θT), one of the indicators used to evaluate water repellency. [Figure 4] An explanatory diagram of the advancing contact angle (θA) in contact angle hysteresis (△θ), another indicator used to evaluate water repellency. [Figure 5] An explanatory diagram of the receding contact angle (θR) in contact angle hysteresis (△θ), another indicator used to evaluate water repellency. [Figure 6] This figure shows the relationship between the amount of PEG-modified silicone oil added and θS, θA, and θR in this embodiment. [Figure 7] This figure shows the relationship between the amount of PEG-modified silicone oil added and Δθ in this embodiment. [Figure 8]This figure shows the relationship between the amount of PEG-modified silicone oil added and θT in this embodiment. [Figure 9] This figure shows the change in hydrolysis over time of a hydrophilic, hydrophobic coating prepared using PEG-modified silicone oil in this embodiment. [Figure 10] This diagram shows the time-dependent changes in the hydrolysis properties of a conventional hydrophilic-hydrophobic coating (without the addition of PEG-modified silicone oil). [Figure 11] This figure shows the relationship between the sliding angle (θT) of a hydrophilic-hydrophobic coating made using a specific organosilicon compound in this embodiment and the size of a water droplet. [Figure 12] This figure shows the change in hydrolysis over time of a hydrophilic and hydrophobic coating prepared using a specific organosilicon compound in this embodiment. [Modes for carrying out the invention]

[0019] The present invention provides a hydrophilic water-repellent treatment agent, a surface treatment method using the hydrophilic water-repellent treatment agent, and a substrate on which a hydrophilic water-repellent film is formed. The present invention will now be described in more detail, including its best mode, in specific embodiments (hereinafter also referred to as "these embodiments"). However, the present invention is not limited to these embodiments, and various other embodiments are included as long as they fall within the scope of the technical idea described in the claims. When numerical ranges are indicated using "~", it means that the lower and upper limits of that range are also included.

[0020] <Hydrophilic and water-repellent treatment agent containing silicone oil (C)> One embodiment of this invention is a hydrophilic water-repellent treatment agent comprising an organosilicon compound (A) in which at least one silicon atom is bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, a metal alkoxide (B), and a silicone oil (C) with a molecular weight of 1000 or less, represented by the following general formula (1).

[0021] [ka] (In the formula, R 1 represents a hydrophilic chain-containing group, R 2 Each of these independently represents an alkyl group with 1 to 5 carbon atoms, where m and n are integers, and m / n is between 1 and 6.

[0022] [Silicone oil (C)] In this embodiment, the R in formula (1) of the silicone oil (C) with a molecular weight of 1000 or less 1 R 3 -O(CH2CH2O) p It is preferable that the silicone oil be -CH3. Hereinafter, this silicone oil will also be referred to as PEG-modified silicone oil. When the molecular weight of the PEG-modified silicone oil exceeds 1000, the mobility of the hydrophilic chain-containing groups decreases, resulting in a decrease in dynamic hydrophilicity. Furthermore, even if the molecular weight is 1000 or less, it is preferable to use a small amount in order to maintain the mobility of the hydrophilic chain-containing groups.

[0023] Preferred PEG silicone oils with a molecular weight of 1000 or less include, for example, Gelest, Inc.'s DBE-712 (molecular weight 600, PEG ratio 60-70%) and DBE-814 (molecular weight 1000, PEG ratio 80-85%). The PEG ratio refers to the molecular weight of the PEG silicone oil excluding the siloxane (Si-O-Si) moiety, and therefore essentially represents the molecular weight of the PEG units in the PEG silicone oil. Furthermore, the amount added is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 1% by mass or less, relative to the mass of the organosilicon compound (A) and metal alkoxide (B) that remain as solid matter after film formation.

[0024] [Organosilicon compounds (A)] In this embodiment, organosilicon compound (A) is a compound in which at least one silicon atom is bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group.

[0025] Since a silicon atom is a tetravalent element, it can be bonded to up to four groups. In this invention, at least one of the four groups is a hydrophilic chain-containing group, and at least one is a hydrolyzable group. Therefore, the remaining two groups bonded to the silicon atom are not particularly limited and may be a hydrophilic chain-containing group, a hydrolyzable group, or any other group. Furthermore, if there are multiple hydrophilic chain-containing groups or multiple hydrolyzable groups, the hydrophilic chain-containing groups and hydrolyzable groups may be the same or different from each other.

[0026] In this embodiment, the preferred organosilicon compound (A) is an organosilicon compound (A1) represented by the following formula (2), having one hydrophilic chain-containing group and three hydrolyzable groups per silicon atom.

[0027] [ka] (In the formula, R 4 R is an alkyl group having 1 to 5 carbon atoms. 5 , R 6 is an alkylene group having 1 to 5 carbon atoms, q is an integer greater than or equal to 4, and each R 5 They may be the same or different from each other, R 7 These are each an alkyl group having 1 to 5 carbon atoms.

[0028] (Hydrophilic chain-containing group) In the organosilicon compound (A) represented by formula (2) above, the group represented by the following formula (4) corresponds to the hydrophilic chain-containing group.

[0029] [ka] R 5 The repeating structural units to which oxygen is bonded play a role in exhibiting hydrophilicity. R 5 The alkylene group having 1 to 5 carbon atoms is preferably an ethylene group. 5Because it is an ethylene group, it is possible to ensure water droplet removal while maintaining high hydrophilicity.

[0030] In the hydrophilic chain-containing group shown in formula (4) above, R 5 The number of repeating units q, formed by the bonding of q and oxygen, is usually an integer of 4 or more, and from the viewpoint of availability, it is preferably an integer between 4 and 12. When q is 4 or more, the chain length that exhibits hydrophilicity becomes longer, increasing the hydrophilicity of the organosilicon compound (A), and as a result, the resulting hydrophilicity becomes sufficient.

[0031] Furthermore, in the hydrophilic chain-containing group represented by formula (4) above, R 4 is an alkyl group having 1 to 5 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group. The presence of a methoxy group with a methyl group and oxygen bonded to the terminal, R 4 Compared to the case of H, hydrogen bonding with water can be suppressed.

[0032] In the hydrophilic chain-containing group represented by formula (4) above, R 6 This is the part that bonds to the silicon atom, and it is an alkylene group with 1 to 5 carbon atoms. 6 The alkylene group having 1 to 5 carbon atoms is usually linear, and being linear allows for better water droplet removal.

[0033] (hydrolyzable group) The hydrolyzable group in organosilicon compound (A) is not particularly limited as long as it is a group that yields a hydroxyl group (silanol group) upon hydrolysis. Furthermore, in organosilicon compound (A) of the present invention, it is sufficient that at least one hydrolyzable group is bonded to the silicon atom, but it is preferable that three hydrolyzable groups are bonded to the silicon atom. When two or three hydrolyzable groups are bonded to the silicon atom, the hydrolyzable groups may be the same or different from each other.

[0034] The hydrolyzable groups in organosilicon compound (A) are sites that react with metal alkoxide (B), as well as sites that react with OH groups generated by the hydrolysis of PEG silicone oil (C), and with the substrate to which the hydrophilic water-repellent treatment agent is applied. Therefore, the hydrolyzable groups in organosilicon compound (A) react with the interior of the formed film while also reacting with the substrate to which the film is formed, thereby increasing the adhesion strength of the formed film to the substrate.

[0035] In this embodiment, the hydrolyzable group of the organosilicon compound (A) is the OR in formula (2). 7 The hydrolyzable group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, ethoxy group, propoxy group, or butoxy group, and particularly preferably a methoxy group or ethoxy group. Because the hydrolyzable group is a methoxy group, the alcohol produced after hydrolysis is of low molecular weight, allowing the treatment agent in contact with the substrate to be dried and film-formed at a lower temperature.

[0036] The content of organosilicon compound (A) in the hydrophilic water-repellent treatment agent according to this embodiment is preferably 0.01 to 30% by mass, more preferably 0.05 to 20% by mass, and even more preferably 0.1 to 10% by mass, relative to the total treatment agent.

[0037] [Metal alkoxide (B)] In this invention, the metal alkoxide (B) is a compound in which an alkoxy group is bonded to a metal atom. The metal alkoxide acts as a binder, improving adhesion / bonding not only to the substrate but also to the organosilicon compound (A) and PEG silicone oil (C). Furthermore, the metal alkoxide (B) forms spaces between the hydrophilic chain-containing groups, thereby improving the mobility of the hydrophilic chain-containing groups.

[0038] In this embodiment, the metal alkoxide (B) preferably has a structure represented by the following general formula (5).

[0039] [ka] (In the formula, M is a trivalent or tetravalent metal atom, R is an alkyl group having 1 to 5 carbon atoms, which may be the same or different from each other, and r is an integer of 3 or 4, depending on the valency of M.) Furthermore, the metal alkoxide (B) in this embodiment may be a hydrolysis condensate of the compound represented by formula (5) above. Here, a hydrolysis condensate means a compound in which all or some of the alkoxy groups contained in the metal alkoxide (B) are condensed by hydrolysis.

[0040] Examples of metal M constituting the metal alkoxide (B) include trivalent metals such as Al, Fe, and In, and tetravalent metals such as Hf, Si, Ti, Sn, and Zr. Among these, Si is preferred from the viewpoint of availability and storage stability.

[0041] Furthermore, when metal M is a trivalent metal, three alkoxy groups RO are bonded, meaning that r in formula (5) above is 3. When metal M is a tetravalent metal, four alkoxy groups RO are bonded, meaning that r in formula (5) above is 4.

[0042] The alkoxy group RO preferably has 1 to 4 carbon atoms, and to allow the treatment agent in contact with the substrate to dry at a lower temperature and facilitate film formation, it is more preferable that it be a methoxy or ethoxy group with 1 or 2 carbon atoms.

[0043] Furthermore, if the hydrolyzable group of organosilicon compound (A) is an alkoxy group, the alkoxy group of organosilicon compound (A) and the alkoxy group of metal alkoxide (B) may be the same or different.

[0044] The content of metal alkoxide (B) in the hydrophilic water-repellent treatment agent according to this embodiment is preferably 0.01 to 30% by mass, more preferably 0.05 to 20% by mass, and even more preferably 1.0 to 10% by mass, relative to the total treatment agent.

[0045] For organosilicon compound (A), the molar ratio (A / B) is preferably 0.01 to 0.5, and more preferably in the range of 0.03 to 0.3. In this embodiment, the metal alkoxide (B) forms a space between the chain-like hydrophilic chain-containing groups of organosilicon compound (A), improving the mobility of the hydrophilic chain-containing groups and enabling the formation of a film that balances hydrophilicity and water droplet removal properties, which are difficult to achieve simultaneously. If the molar ratio (A / B) of organosilicon compound (A) to metal alkoxide (B) is in the range of 0.01 to 0.5, an appropriate space can be formed between the chain-like hydrophilic chain-containing groups, and as a result, a good balance between hydrophilicity and water droplet removal properties can be achieved.

[0046] [Other ingredients] In this embodiment, the hydrophilic water-repellent treatment agent may optionally contain other components in addition to the organosilicon compound (A) and metal alkoxide (B) described above. Examples of other components include solvents, catalysts, and additives.

[0047] Examples of solvents include water, hydrophilic organic solvents such as alcohol-based solvents, ether-based solvents, ketone-based solvents, ester-based solvents, and amide-based solvents, and hydrophobic organic solvents such as aromatic hydrocarbon-based solvents and saturated hydrocarbon-based solvents. These may be used individually or in combination of two or more.

[0048] Preferably, the catalyst acts as a hydrolysis catalyst. Examples include acidic compounds such as hydrochloric acid, nitric acid, and acetic acid; basic compounds such as ammonia and amines; and organometallic compounds with a metal element as the central metal.

[0049] As additives, for example, antioxidants, rust inhibitors, ultraviolet absorbers, light stabilizers, fungicides, antibacterial agents, biofouling inhibitors, deodorizers, pigments, flame retardants, antistatic agents, etc., can be arbitrarily selected and blended within a range that does not hinder the effects of the present invention, as long as they exhibit the desired function.

[0050] In this embodiment, the hydrophilic water-repellent treatment agent preferably has a total solid content of 30% or less, more preferably 20% or less, and particularly preferably about 10%.

[0051] <Hydrophilic and water-repellent treatment agent containing organosilicon compounds (A2)> Another embodiment of this model is a hydrophilic water-repellent treatment agent comprising an organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, and a metal alkoxide (B), wherein the organosilicon compound (A) is the organosilicon compound (A2) represented by the following formula (3).

[0052] [ka] (In the formula, each R 8 Each of these is an alkyl group having 1 to 5 carbon atoms, and each R 9 Each of these is an alkylene group with 1 to 5 carbon atoms, and R 10 is an alkylene group having 1 to 5 carbon atoms, q is an integer greater than or equal to 4, and each R 10 They may be the same or different from each other.

[0053] In other words, the organosilicon compound (A2) according to this embodiment is characterized by being a so-called hexafunctional type, in which a polyalkylene glycol structure, which is a hydrophilic chain-containing group, is bonded between the silicon atoms at both ends, and three alkoxy groups, which are hydrolyzable groups, are bonded to each of the silicon atoms at both ends.

[0054] Based on the hypothesis that a larger number of terminal hydrolyzable groups increases the number of reaction sites, thereby improving adhesion to the substrate and bonding with the metal alkoxide (B), the inventors used various hexafunctional organosilicon compounds as organosilicon compounds (A) in combination with metal alkoxides (B) to form a film. As a result, it was found that using compound (A2) represented by formula (3) above significantly improved hydrophilicity while maintaining hydrophobicity, compared to using trifunctional organosilicon compound (A1) represented by formula (2).

[0055] On the other hand, even among organosilicon compounds of the same hexafunctional type, the compounds in Comparative Examples 6 and 7, described later, which have hydroxyl groups or urethane bonds between the polyalkylene glycol structure and the silicon atoms at both ends, showed decreased hydrophilicity and no improvement in hydrophobicity. This is presumed to be due to hydrogen bonding between water and these oxygen-containing polar groups.

[0056] In equation (3) above, R 8 -O is an alkoxy group having 1 to 5 carbon atoms, but to ensure that the alcohol produced after hydrolysis is low molecular weight, and to allow the treatment agent to dry at a lower temperature and form a film, it is preferable that the number of carbon atoms in the hydrolyzable group be small. It is preferably a methoxy group, ethoxy group, propoxy group, or butoxy group, and more preferably a methoxy group or ethoxy group.

[0057] R 9 This is an alkylene group having 1 to 5 carbon atoms, and due to its availability, it is preferably an ethylene group, a propylene group, or a butylene group, and is particularly preferably a propylene group.

[0058] The aforementioned R 10 The number of repeating units q of -O is an integer of 4 or more, and from the viewpoint of availability, it is preferably an integer between 4 and 30. When q is 4 or more, the chain length that exhibits hydrophilicity becomes longer, increasing the hydrophilicity of the organosilicon compound (A), and as a result, the hydrophilicity of the formed film becomes sufficient. Also, R 10 While the group is an alkylene group having 1 to 5 carbon atoms, an ethylene group is preferable in order to ensure water droplet removal while maintaining high hydrophilicity.

[0059] The metal alkoxide (B) and other components according to this embodiment can be the same as those described in the first embodiment.

[0060] <Surface treatment method and substrate on which a hydrophilic and hydrophobic coating has been formed> Another embodiment of this model is a surface treatment method that includes a hydrophilic and hydrophobic coating formation step, in which a hydrophilic and hydrophobic coating is formed by contacting the surface of a substrate to be given hydrophilic and hydrophobic properties with a hydrophilic and hydrophobic coating agent containing silicone oil (C) or an organosilicon compound (A2) according to the above embodiment, as described above. Another aspect of this embodiment is a substrate on which a hydrophilic and hydrophobic coating containing a hydrolyzed and condensed polymer of the hydrophilic and hydrophobic treatment agent according to this embodiment is formed on its surface.

[0061] [Hydrophilic and slippery film formation process] In the hydrophilic-hydrophobic coating formation step, the hydrophilic-hydrophobic treatment agent according to this embodiment is brought into contact with the surface of the substrate, which has been pre-treated as needed, to form a hydrophilic-hydrophobic coating.

[0062] The method for bringing the hydrophilic water-repellent treatment agent into contact with the substrate is not particularly limited, and known methods can be applied. Examples include spin coating, dip coating, spray coating, roll coating, bar coating, and die coating.

[0063] The conditions such as temperature when contacting the hydrophilic water-repellent treatment agent are not particularly limited, and known conditions can be applied.

[0064] Figure 1 shows an example of the procedure for forming a hydrophilic and hydrophobic coating according to this embodiment. The hydrophilic and water-repellent coating according to this embodiment can be formed by coating the surface of a substrate to which hydrophilic and water-repellent properties are to be imparted with a treatment agent obtained by thoroughly stirring and mixing an organosilicon compound (A), a metal alkoxide (B), and PEG-modified silicone oil (C), or a hexafunctional organosilicon compound (A2) and a metal alkoxide (B) as other components with a solvent and a hydrolysis catalyst, etc., and then subjecting it to a heat treatment to induce a hydrolysis and condensation polymerization reaction.

[0065] [Hydrophilic and slippery film] (Hydrolyzed and condensed polymers contained in hydrophilic and hydrophobic coatings) The hydrophilic and hydrophobic coating formed on the substrate by contacting it with a hydrophilic and hydrophobic treatment agent containing silicone oil (C) according to this embodiment comprises a hydrolyzed and condensed polymer of an organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, a metal alkoxide (B), and a silicone oil (C) represented by the following general formula (1) with a molecular weight of 1000 or less.

[0066] [ka] (In the formula, R 1 represents a hydrophilic chain-containing group, R 2 Each of these independently represents an alkyl group with 1 to 5 carbon atoms, where m and n are integers, and m / n is between 1 and 6.

[0067] Furthermore, the hydrophilic and hydrophobic coating formed on the substrate by contacting it with a hydrophilic and hydrophobic treatment agent containing an organosilicon compound (A2) according to this embodiment comprises a hydrolyzed and condensed polymer of an organosilicon compound (A), which is an essential component of the hydrophilic and hydrophobic treatment agent, having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, and a metal alkoxide (B), wherein the organosilicon compound (A) is represented by the following formula (3).

[0068] [ka] (In the formula, each R 8 Each of these is an alkyl group having 1 to 5 carbon atoms, and each R 9 Each of these is an alkylene group with 1 to 5 carbon atoms, and R 10 is an alkylene group having 1 to 5 carbon atoms, q is an integer greater than or equal to 4, and each R 10 They may be the same or different from each other.

[0069] (film thickness) The film thickness of the hydrophilic and hydrophobic coating according to this embodiment is not particularly limited, but is preferably 0.05 g / m². 2 The above applies, more preferably 0.1~2 g / m 2 The film thickness is 0.05 g / m². 2 By doing so, the substrate can be sufficiently covered, thus protecting it from friction / wear and rust.

[0070] (Static contact angle θ S ) The static hydrophilicity of a hydrophilic-superabsorbent coating is indicated by the static contact angle θ of water with respect to the coating. S You can use it. As shown in Figure 2, the static contact angle θ S This is the angle between the liquid surface and the solid surface of a stationary droplet; the smaller this value, the higher the static hydrophilicity. Static contact angle θ of the hydrophilic and hydrophobic coating according to this embodiment S It is preferable that the static contact angle θ is less than 40°. S If the temperature is below 40°, it can be fully utilized not only in the field of stain resistance for buildings, but also in the field of heat exchangers.

[0071] (slip angle θ T ) One indicator of the hydrophilic-hydrophobic properties of a hydrophilic coating is the sliding angle θ. T You can use it. As shown in Figure 3, the sliding angle θ T This value represents the angle of inclination of a solid surface required for a liquid droplet to gradually tilt and begin to slide down. The smaller this value, the better the water-repellent properties. In this embodiment, the hydrophilic coating has a water sliding angle θ relative to the coating. T However, for a volume of 10 μL of water droplets, the angle of water sliding down is preferably 25° or less, and more preferably 20° or less. T The lower limit is not particularly restrictive; the lower the better.

[0072] (Contact angle hysteresis (Δθ=θ) A -θ R )) In addition to the hydrophilic-hydrophobic coating, contact angle hysteresis (Δθ) can also be used as an indicator of its hydrophobicity. Contact angle hysteresis Δθ is the advancing contact angle θ due to the expansion and contraction of a droplet in contact with a solid surface. A and the receding contact angle θ R The difference (θ) A -θ R It can be calculated from ). As shown in Figure 4, the advancing contact angle θ A This is the contact angle when the three-phase contact line advances as the liquid volume is gradually increased after inserting a syringe needle into a droplet formed on a solid surface. Furthermore, as shown in Figure 5, the receding contact angle θ R This is the contact angle when the three-phase contact line retracts as the droplet is gradually drawn in. Smaller values ​​for the advancing and receding contact angles indicate higher dynamic hydrophilicity, while smaller values ​​for contact angle hysteresis indicate higher hydrophobicity.

[0073] (hydrolytic stability) Hydrolysis stability is essential for hydrophilic and hydrophobic coatings formed on substrates that are intended to come into contact with water droplets or water films. The hydrophilic and hydrophobic coating according to this embodiment maintains a static contact angle θ even when in contact with water for extended periods. S , advancing contact angle θ A , receding contact angle θ R Furthermore, it is preferable that the change in the value of the contact angle hysteresis Δθ is small.

[0074] [Base material] The substrate according to this embodiment is not particularly limited as long as it can produce a hydrophilic and water-repellent coating containing a hydrolyzed and condensed polymer of the organosilicon compound (A), metal alkoxide (B), and silicone oil (C) with a molecular weight of 1000 or less, or a hydrophilic and water-repellent coating containing a hydrolyzed and condensed polymer of the organosilicon compound (A2) and metal alkoxide (B) by contacting it with the hydrophilic and water-repellent treatment agent. Examples include thermoplastic resins such as acrylic resin, polycarbonate resin, polyester resin, styrene resin, acrylic-styrene copolymer resin, cellulose resin, polyolefin resin, and polyvinyl alcohol, and thermosetting resins such as phenolic resin, urea resin, melamine resin, epoxy resin, unsaturated polyester, silicone resin, and urethane resin. Other examples include ceramics, glass, metals such as iron, silicon, copper, zinc, and aluminum, and alloys containing the aforementioned metals.

[0075] Furthermore, a degreasing process may be performed on the substrate before the hydrophilic-hydrophobic coating formation process, which involves degreasing and subsequent washing with water.

[0076] Alternatively, the resin substrate may be subjected to pretreatment such as an easy-adhesion treatment. Examples of easy-adhesion treatments include corona treatment, plasma treatment, ultraviolet treatment, silane compounds, silica (SiO2) film, or resin primer treatment. Furthermore, metal and alloy substrates may be coated with an SiO2 film. This improves the adhesion between the hydrophilic / hydrophobic film and the substrate, thereby improving the durability of the film against alkaline or acidic treatments and the corrosion resistance of the metal or alloy substrate.

[0077] For example, heat exchanger fins are an application where both hydrophilicity and water droplet removal properties are required, and a self-cleaning function is desired. The surface treatment method of the present invention can be suitably applied to aluminum, which is the base material for heat exchanger fins.

[0078] Also, the shape of the base material is not particularly limited, and for example, it may be a flat surface, a curved surface, or a three-dimensional structure formed by combining a number of surfaces.

Example

[0079] Next, examples of the present invention will be described, but the present invention is not limited to these examples and the like.

[0080] <Examination of the presence or absence of PEG-modified silicone oil and molecular weight> (Examples 1, 2, Comparative Examples 1 to 5) As the organosilicon compound (A), 2.35 g of the compound PEG9-12-Si (Gelest, Inc.) (A1) shown in the following formula (6) was weighed, and as the metal alkoxide (B), tetraethoxysilane TEOS (Wako Pure Chemical Industries, Ltd. (currently Fujifilm Wako Pure Chemical Corporation)) 5.17 g (molar ratio A / B = 0.15) was weighed. Further, 0.16 g of various PEG-modified silicone oils (Gelest, Inc.) shown in Table 1 below was weighed (corresponding to 3% by mass based on the mass derived from the components of the organosilicon compound (A1) and the metal alkoxide (B) remaining after film formation) and mixed. These were stirred with 44.5 mL of ethanol and 14.8 mL of 0.01 M hydrochloric acid at room temperature overnight to prepare the hydrophilic lubricating treatment agents according to Examples 1, 2 and Comparative Examples 1 to 4.

[0081]

Chemical formula

[0085] Static contact angles θ of Examples 1 and 2 and Comparative Examples 1 to 5 S , advancing contact angle θ A , receding contact angle θ R , contact angle hysteresis Δθ, and sliding angle θ for a 10 μL water droplet T are shown in Table 2. Note that "-" indicates unmeasured.

[0086]

Table 2

[0087] As shown in Table 1, since the viscosity of PEG-modified silicone oil decreases as the molecular weight decreases, in the hydrophilic and lubricious treatment agents of Examples 1 and 2 in which PEG-modified silicone oil (C) with a molecular weight of 1000 or less was added to organosilicon compound (A) and metal alkoxide (B), the increase in viscosity was suppressed. From Table 2, it was found that the hydrophilic and lubricious film formed using this treatment agent shows a static hydrophilic contact angle θ S value in the first half of the 30° range, and the θ A , θ R indicating dynamic hydrophilicity is also smaller than that of Comparative Example 5, indicating that the hydrophilicity has been improved. On the other hand, the values of contact angle hysteresis Δθ and sliding angle θ T were slightly higher than those of Comparative Example 5 without the addition of PEG-modified silicone oil. In particular, in Example 1 with the addition of DBE-712, Δθ was less than 10° and θ T was less than 25°, indicating that it was possible to maintain lubricity almost comparable to that of Comparative Example 5.

[0088] (Amount of PEG-modified silicone oil added) A hydrophilic and lubricious treatment agent was prepared by changing the addition amount of PEG-modified silicone oil DBE-712 in Example 1 with respect to the total mass of organosilicon compound (A) and metal alkoxide (B), and a hydrophilic and lubricious film was formed. Static contact angle θ with respect to the presence or absence of DBE-712 and changes in the amount added. S , advancing contact angle θ A , receding contact angle θ R , contact angle hysteresis Δθ, and sliding angle θ T The measurement results are shown in Table 3. Figure 6 shows the static contact angle θ. S , advancing contact angle θ A , receding contact angle θ R The change in , is shown in Figure 7, the change in contact angle hysteresis Δθ is shown in Figure 8, and the sliding angle θ is shown in Figure 8. T This shows the change.

[0089] [Table 3]

[0090] Figure 6 shows that the improvement in hydrophilicity due to the addition of DBE-712 is effective with an addition of 0.01 to 10% by mass. On the other hand, regarding water repellency, Figures 7 and 8 show that with the addition of approximately 0.01 to 5% by mass of DBE-712, the contact angle hysteresis Δθ and sliding angle θ are comparable to those without the addition. T It was found that it could be maintained.

[0091] (hydrolytic stability) The hydrophilic and hydrophobic coatings prepared in Example 1 and Comparative Example 5 were immersed in water for 7 days, and the coatings were removed every 24 hours to determine the static contact angle θ. S , advancing contact angle θ A , receding contact angle θ R We measured it. The results for Example 1 are shown in Table 4 and Figure 9, and the results for Comparative Example 5 are shown in Table 5 and Figure 10.

[0092] [Table 4]

[0093] [Table 5]

[0094] Comparing Table 4 and Figure 9, which show the results of the hydrophilic-hydrophobic coating according to Example 1, with Table 5 and Figure 10, which show the results of the hydrophilic-hydrophobic coating according to Comparative Example 5, which corresponds to a conventional example, the conventional coating (Comparative Example 5) showed increased hydrophilicity over time, but its hydrophobicity deteriorated significantly. On the other hand, the coating prepared by adding PEG-modified silicone oil (C) with a molecular weight of 1000 or less (Example 1) showed a static contact angle θ S , advancing contact angle θ A , receding contact angle θ R、 Furthermore, it was found that there was no significant change in the contact angle hysteresis Δθ over time, indicating excellent hydrolysis stability.

[0095] <Investigation of organosilicon compounds> (Example 3, Comparative Examples 6-8) A hydrophilic and hydrophobic coating according to Example 3 was formed in the same manner as in Comparative Example 5, except that, as the organosilicon compound (A), a silane having polyethylene glycol as shown in formula (7) (Gelest, Inc.: hereinafter referred to as "PEG25-30-Si2") (A2) was used instead of the compound shown in formula (6), TEOS was used as the metal alkoxide (B), and A / B were mixed in a molar ratio of 0.15, ethanol and hydrochloric acid were added so that the solid content was approximately 12% by mass, and the mixture was stirred overnight at room temperature to prepare a precursor solution.

[0096] [ka]

[0097] Except for using the compounds shown in formulas (8) to (10) below as organosilicon compounds, hydrophilic and hydrophobic coatings corresponding to Comparative Examples 6 to 8 were formed in the same manner as in Comparative Example 5.

[0098] [ka]

[0099] [ka]

[0100] [ka]

[0101] Static contact angle θ of hydrophilic and hydrophobic coatings in Example 3 and Comparative Examples 6-8 S , advancing contact angle θ A , receding contact angle θ R The contact angle hysteresis Δθ, along with that of the film related to Comparative Example 5, is shown in Table 6. Note that "..." represents the forward contact angle θ A , receding contact angle θ R This indicates that the contact angle hysteresis Δθ was too poor to measure.

[0102] [Table 6]

[0103] From the results in Table 6, the film according to Example 3, which was prepared using PEG25-30-Si2, an organosilicon compound having a hydrophilic chain group containing PEG and six hydrolyzable groups, has a static contact angle θ S , advancing contact angle θ A , and receding contact angle θ R Not only is the contact angle hysteresis Δθ small, resulting in excellent static and dynamic hydrophilicity, but the low contact angle hysteresis Δθ also indicates a significant improvement in water-repellent properties compared to the film in Comparative Example 5, a conventional example. In contrast, the films produced using Comparative Examples 6 and 7, which have hydrophilic chain groups containing PEG and six hydrolyzable groups, but also contain OH groups and NHCOO groups, did not surpass the hydrophilic and hydrophobic properties of Comparative Example 5. Furthermore, the film prepared using EG2-OH-Si without PEG units, which was examined as Comparative Example 8, failed to achieve water repellency.

[0104] (Organosilicon compound (A2) / Metal alkoxide (B)) The static contact angle θ when a hydrophilic-hydrophobic coating is formed by changing the molar ratio of PEG-25-30-Si2 and TEOS used in Example 3. S , advancing contact angle θ A , receding contact angle θ R The contact angle hysteresis Δθ is shown in Table 7 below.

[0105] [Table 7]

[0106] Table 7 shows that when the molar ratio of PEG-25-30-Si2 to TEOS is 0.3 or less, superior hydrophilicity and hydrophobicity can be obtained compared to the conventional example, Comparative Example 5.

[0107] (slip angle) The sliding angle θ of the coating in Example 3 and Comparative Example 5 T The measurements were taken by changing the water droplet size from 1 to 50 μL. The results are shown in Table 8 and Figure 11 below. Note that "-" indicates that measurement was not performed.

[0108] [Table 8]

[0109] Table 8 and Figure 11 show that on the hydrophilic-hydrophobic coating prepared using PEG-25-30-Si2 according to Example 3, a 2 μL water droplet tilts θ at a 24° angle. T It was found to slide on water. In the conventional film according to Comparative Example 5, a 42° inclination was required for a 5 μL water droplet to slide off, and droplets of 2 μL or less could not slide off.

[0110] (hydrolytic stability) The hydrophilic-hydrophobic coating prepared in Example 3 was immersed in water for 7 days, and the coating was removed every 24 hours to obtain the static contact angle θ. S , advancing contact angle θ A , receding contact angle θ R、 The contact angle hysteresis Δθ was also measured. The results for Example 3 are shown in Table 9 and Figure 12.

[0111] [Table 9]

[0112] Comparing Table 9 and Figure 12, which show the results of the hydrophilic-hydrophobic coating according to Example 3, with Table 5 and Figure 10, which show the results of the hydrophilic-hydrophobic coating according to Comparative Example 5, which corresponds to a conventional example, the conventional coating showed increased hydrophilicity over time, but its hydrophobicity deteriorated significantly. However, the coating made using PEG25-30-Si2 showed a static contact angle θ S , advancing contact angle θ A , receding contact angle θ R、 Furthermore, it was found that there was no significant change in the contact angle hysteresis Δθ over time, indicating excellent hydrolysis stability. [Industrial applicability]

[0113] The hydrophilic and hydrophobic coating formed using the hydrophilic and hydrophobic treatment agent according to this embodiment possesses both hydrophilic and hydrophobic properties, and can therefore be applied to components that exhibit a self-cleaning function. For this reason, it can be used in applications where both hydrophilic and hydrophobic properties are required and a self-cleaning function is desired, such as components of heat exchangers used in heat pump systems that use air as a heat source, or in transportation equipment, and is particularly suitable for use as fin material for heat exchangers.

[0114] Furthermore, it can be widely applied to various components such as refrigeration equipment, power transmission equipment, communication equipment, and road infrastructure, as well as to window glass of automobiles, vehicles, and buildings, where both hydrophilicity and water droplet removal properties are required in environments that come into contact with water, and where a self-cleaning function is desired.

Claims

1. An organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, Metal alkoxide (B) and A silicone oil (C) with a molecular weight of 1000 or less, represented by the following general formula (1), A hydrophilic and water-repellent treatment agent containing [specific ingredient / material]. 【Chemistry 1】 (In the formula, R １ represents a hydrophilic chain-containing group, R ２ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, where m and n are integers, and m / n is between 1 and 6.

2. In the formula (1), R １ is a group represented by R ３ -O(CH ２ CH ２ O) ｐ -CH ３ (R ３ is an alkylene group having 1 to 5 carbon atoms, and p is an integer of 5 to 10). The hydrophilic lubrication treatment agent according to claim 1.

3. The hydrophilic water-repellent treatment agent according to claim 1, wherein the organosilicon compound (A) is an organosilicon compound (A1) represented by the following general formula (2). 【Chemistry 2】 (In the formula, R ４ R is an alkyl group having 1 to 5 carbon atoms. ５ , R ６ is an alkylene group having 1 to 5 carbon atoms, q is an integer of 4 or more, and each R ５ They may be the same or different from each other, R ７ These are each an alkyl group having 1 to 5 carbon atoms.

4. An organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, Metal alkoxide (B) and Includes, The organosilicon compound (A) is an organosilicon compound (A2) represented by the following formula (3), and is a hydrophilic and water-repellent treatment agent. 【Transformation 3】 (In the formula, each R ８ Each of these is an alkyl group having 1 to 5 carbon atoms, and each R ９ Each of these is an alkylene group having 1 to 5 carbon atoms, and R １０ is an alkylene group having 1 to 5 carbon atoms, q is an integer of 4 or more, and each R １０ They may be the same or different from each other.

5. A surface treatment method comprising a step of forming a hydrophilic and hydrophobic film by contacting the surface of a substrate with a hydrophilic and hydrophobic treatment agent according to any one of claims 1 to 4 to form a hydrophilic and hydrophobic film.

6. The surface treatment method according to claim 5, wherein the substrate is at least one selected from metal, metal oxide, silicon, glass, or resin.

7. The surface treatment method according to claim 5, wherein the substrate is a fin material for a heat exchanger.

8. On the surface, An organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, Metal alkoxide (B) and A silicone oil (C) with a molecular weight of 1000 or less, represented by the following general formula (1), A substrate on which a hydrophilic and hydrophobic coating containing hydrolyzed and condensed polymers has been formed. 【Chemistry 4】 (In the formula, R １ represents a hydrophilic chain-containing group, R ２ Each of these independently represents an alkyl group having 1 to 5 carbon atoms, where m and n are integers, and m / n is between 1 and 6.

9. In the above formula (1), R １ R ３ -O(CH ２ CH ２ O) ｐ -CH ３ (R ３ The substrate according to claim 8, wherein the group is represented by an alkylene group having 1 to 5 carbon atoms, and p is an integer from 5 to 10.

10. The substrate according to claim 8, wherein the organosilicon compound (A) is an organosilicon compound (A1) represented by the following general formula (2). 【Transformation 5】 (In the formula, R ４ R is an alkyl group having 1 to 5 carbon atoms. ５ , R ６ is an alkylene group having 1 to 5 carbon atoms, q is an integer of 4 or more, and each R ５ They may be the same or different from each other, R ７ These are each an alkyl group having 1 to 5 carbon atoms.

11. On the surface, An organosilicon compound (A) having at least one silicon atom bonded to at least one hydrophilic chain-containing group and at least one hydrolyzable group, It contains a metal alkoxide (B) and a hydrolysis / condensation polymer thereof. The aforementioned organosilicon compound (A) is an organosilicon compound (A2) represented by the following formula (3), and the substrate has a hydrophilic and hydrophobic coating formed on it. 【Transformation 6】 (In the formula, each R ８ Each of these is an alkyl group having 1 to 5 carbon atoms, and each R ９ Each of these is an alkylene group having 1 to 5 carbon atoms, and R １０ is an alkylene group having 1 to 5 carbon atoms, q is an integer of 4 or more, and each R １０ They may be the same or different from each other.

12. The substrate according to any one of claims 8 to 11, wherein the substrate is at least one selected from metal, metal oxide, silicon, glass, or resin.

13. The substrate is a fin material for a heat exchanger, according to any one of claims 8 to 11.

Images