Surface treatment method, surface treatment kit

Abstract

To provide a new surface treatment method not only capable of imparting water repellency and oil repellency to a surface of a product to be treated but also capable of improving finger slipperiness, and a surface treatment kit.SOLUTION: A surface treatment method includes: a glass coating step of coating a surface of a product to be treated with a glass coating solution containing polysilazane; and a fluorine coating step of coating the surface of the product to be treated with a fluorine coating solution containing perfluoropolyether silane. The glass coating step and the fluorine coating step are sequentially executed to form a coat with water repellency and oil repellency on the surface of the product to be treated.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a surface treatment method for forming a water-repellent and oil-repellent coating on the surface of an object to be treated, and a surface treatment kit. [Background technology]

[0002] Many methods have been developed to impart water repellency to the surface of an object to be treated, such as polysilazane coating, silicone oligomer coating, or perfluoroalkylsilane coating.

[0003] However, many recent industrial products, such as smartphones and car navigation systems, are equipped with touch panels, and the water repellency provided by the polysilazane coating or silicone oligomer coating alone is not enough to effectively prevent adhesion of grease, such as fingerprint stains.

[0004] In this regard, the perfluoroalkylsilane coating can also impart oil repellency to the object to be treated, making it easy to wipe off any grease adhering to the touch panel.

[0005] Although the perfluoroalkylsilane coating has the property of being difficult to form on surfaces other than glass, by pre-coating the polysilazane coating and then top-coating it with the perfluoroalkylsilane coating, it becomes possible to perform surface treatment on painted surfaces and glass surfaces that have already been coated with fluorine (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-59302 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the perfluoroalkyl silane coating has a high coefficient of friction (maximum static friction coefficient (μ0): 0.23 or more), which makes it difficult to smoothly input commands by sliding your finger across the screen, such as flicking and swiping, which are common when using a smartphone.

[0008] The present invention was completed in consideration of the above-mentioned technical problems, and aims to provide a novel surface treatment method and surface treatment kit that can impart water-repellent and oil-repellent properties to the surface of the object to be treated, as well as improve the smoothness of the surface for fingers. [Means for solving the problem]

[0009] The surface treatment method of the present invention for solving the above technical problems is a surface treatment method for forming a coating having water-repellent and oil-repellent properties on the surface of a workpiece, and is characterized by sequentially carrying out a glass coating step of applying a glass coating liquid containing polysilazane to the surface of the workpiece, and a fluorine coating step of applying a fluorine coating liquid containing perfluoropolyether silane to the surface of the workpiece (hereinafter referred to as the "treatment method of the present invention").

[0010] In the treatment method of the present invention, it is preferable to carry out a water treatment step after the glass coating step and before the fluorine coating step, in which moisture is added to the surface of the workpiece to which the glass coating liquid has been applied.

[0011] In the treatment method of the present invention, it is preferable that a first catalyst for accelerating the formation of a coating film of perfluoropolyether silane is blended into the fluorine coating solution during the fluorine coating step.

[0012] The surface treatment kit of the present invention, which solves the above technical problems, is a surface treatment kit for forming a coating having water-repellent and oil-repellent properties on the surface of a workpiece, and is characterized by comprising a glass coating liquid containing polysilazane and a fluorine coating liquid containing perfluoropolyether silane (hereinafter referred to as the "treatment kit of the present invention").

[0013] In a preferred embodiment, the treatment kit of the present invention further comprises a reaction-accelerating liquid agent containing a first catalyst for accelerating the formation of a coating film of perfluoropolyether silane.

[0014] In the treatment kit of the present invention, the first catalyst is preferably trifluoroacetic acid.

[0015] In a preferred embodiment of the treatment kit of the present invention, a second catalyst for accelerating the curing reaction of polysilazane is blended in the glass coating liquid agent.

[0016] In the treatment kit of the present invention, the second catalyst is preferably a metal catalyst. [Effects of the Invention]

[0017] According to the present invention, it is possible to impart water repellency and oil repellency to the surface of an object to be treated, and also to improve the smoothness of the surface for fingers. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment for carrying out the present invention will be described, but the present invention is not limited to this embodiment.

[0019] <Treatment kit of the present invention> The processing kit of the present invention includes a “liquid for glass coating” and a “liquid for fluorine coating.” The processing kit of this embodiment further includes a “liquid for reaction promotion.”

[0020] -Liquid for glass coating- The glass coating liquid agent contains polysilazane. In the present invention, polysilazane refers to a polymer compound having a basic unit of (SiRNR) (R: hydrogen group, alkyl group, or vinyl group). In this embodiment, the glass coating liquid agent was obtained by dissolving a commercially available inorganic polysilazane (manufactured by Merck Ltd., product name: NL120A-20) in a solvent (dibutyl ether + petroleum-based solvent) to a blending amount of 0.3 wt % (net amount of polysilazane). The glass coating liquid agent also contains a second catalyst (in this embodiment, a metal-based catalyst) to promote the curing reaction of polysilazane.

[0021] -Fluorine coating liquid- The fluorine coating solution contains perfluoropolyether silane. In the present invention, perfluoropolyether silane refers to a compound having a structure in which a silyl group (including a silyl group derivative) is bonded to the end of a perfluoropolyether. In this embodiment, the fluorine coating solution was obtained by dissolving commercially available perfluoropolyether silane (manufactured by Unichem Co., Ltd., product name: UEC-001M) in a solvent (hydrofluoroether) to give a blending amount of 0.5 wt % (net amount of perfluoropolyether silane).

[0022] -Reaction accelerating liquid agent- The reaction-accelerating liquid agent contains a first catalyst for accelerating the siloxane bond reaction. In this embodiment, trifluoroacetic acid was selected as the first catalyst, and the reaction-accelerating liquid agent was obtained by dissolving trifluoroacetic acid in a solvent (hydrofluoroether) to a blending amount of 1.0 wt % (net amount of trifluoroacetic acid).

[0023] <Processing method of the present invention> Hereinafter, the processing method of the present invention for forming a water-repellent and oil-repellent coating on the surface of a workpiece using the processing kit of the present invention will be carried out. The processing method of the present invention includes a "glass coating step" and a "fluorine coating step."

[0024] -Glass coating process- In the glass coating step, the glass coating liquid is applied to the surface of the workpiece. In this embodiment, a car navigation display (polyvinyl alcohol liquid crystal screen, screen size: 7 inches) is selected as the workpiece, and the net coating amount of polysilazane on the surface (screen) of the workpiece is 0.12 g / m. 2 The glass coating step was carried out by applying the glass coating liquid agent so that the glass coating temperature was 100°C.

[0025] By carrying out the glass coating process, a glass coating (silica glass) is formed on the surface of the workpiece. This is a reaction that occurs automatically when polysilazane in the glass coating liquid applied to the surface of the workpiece comes into contact with moisture (HO) in the air. In this embodiment, in order to speed up this reaction, a "water treatment process" was carried out after carrying out the glass coating process (and before carrying out the fluorine coating process).

[0026] -Water treatment process- In the water treatment step, moisture is applied to the surface of the object to be treated to which the glass coating liquid has been applied. In this embodiment, the water treatment step was carried out by wiping the surface of the object to be treated with a nonwoven fabric soaked in 0.4 g of water.

[0027] -Fluorine coating process- In the fluorine coating step, the fluorine coating solution is applied to the surface of the workpiece (which has been subjected to the glass coating step). In this embodiment, the net amount of perfluoropolyether silane applied to the surface (screen) of the workpiece is 0.35 g / m. 2 The fluorine coating step was carried out by applying the fluorine coating solution to the surface of the workpiece so that the fluorine coating solution was such that the first catalyst was blended therein. In this embodiment, when carrying out the fluorine coating step, the fluorine coating solution was mixed with the reaction accelerating solution to obtain a fluorine coating solution containing a first catalyst, and this fluorine coating solution containing the first catalyst was applied to the surface of the workpiece.

[0028] By carrying out the fluorine coating process, a perfluoropolyether silane coating is formed on the surface of the workpiece. This is thought to be because the silyl groups of the perfluoropolyether silane react with the silazane groups remaining in the glass coating formed on the surface of the workpiece to form siloxane bonds. That is, in the processing method of the present invention, a glass coating is formed (pre-coated) on the surface of the workpiece by carrying out the glass coating process, so that a perfluoropolyether silane coating can be stably formed by carrying out the subsequent fluorine coating process. As a result, the processing method of the present invention can be carried out regardless of the material of the workpiece.

[0029] Furthermore, the surface of the object treated by the treatment method of the present invention is provided with water repellency and oil repellency by the perfluoropolyether silane coating present in the top layer, which results in good antifouling properties on the surface of the object treated by the treatment method of the present invention.

[0030] Furthermore, because perfluoropolyether silane coatings have a low coefficient of friction (maximum static friction coefficient μ0: 0.08 or less, dynamic friction coefficient μ: 0.08 or less, provided μ0 > μ), the surface of an object treated by the treatment method of the present invention exhibits good finger slipperiness. As a result, if the treatment method of the present invention is applied to the touch panel of a smartphone or car navigation system, command inputs such as flicks and swipes can be smoothly performed by sliding a finger across the screen.

[0031] In this embodiment, a 0.3 wt % inorganic polysilazane solution (solvent: dibutyl ether + petroleum-based solvent) is used as the glass coating liquid, but the polysilazane contained in the glass coating liquid may be a polysilazane having an organic substituent (organic polysilazane). The amount of polysilazane contained in the glass coating liquid is preferably 0.05 to 2.0 wt % (more preferably 0.1 to 1.0 wt %).

[0032] In this embodiment, a second catalyst (a metal-based catalyst in this embodiment) is blended into the glass coating liquid agent to promote the curing reaction of polysilazane. However, since the curing reaction of polysilazane occurs automatically upon contact with moisture in the air, it is not necessarily required to blend the second catalyst into the glass coating liquid agent.

[0033] However, since the addition of the second catalyst accelerates the curing reaction of polysilazane, it is preferable to add the second catalyst to the glass coating liquid in the present invention. As the second catalyst, in addition to metal catalysts, N-heterocyclic compounds, amines, organic acids, or inorganic acids can be appropriately selected and used.

[0034] In this embodiment, a 0.5 wt % perfluoropolyether silane solution (solvent: hydrofluoroether) is used as the fluorine coating solution, but the perfluoropolyether silane contained in the fluorine coating solution may have an organic substituent. The amount of perfluoropolyether silane in the fluorine coating solution is preferably 0.05 to 2.0 wt % (more preferably 0.1 to 1.0 wt %).

[0035] In this embodiment, the reaction-accelerating liquid agent is contained in the processing kit of the present invention, but the reaction-accelerating liquid agent is not an essential component of the processing kit of the present invention.

[0036] However, since mixing the reaction-accelerating liquid agent with the fluorine coating liquid accelerates the formation of a coating film of perfluoropolyethersilane, it is preferable to include the reaction-accelerating liquid agent in the treatment kit of the present invention. As the first catalyst to be blended into the reaction-accelerating liquid agent, an organic acid such as trifluoroacetic acid, as well as an inorganic acid, can be used. It has been confirmed that the amount of the reaction-accelerating liquid agent mixed with the fluorine coating liquid is preferably 0.01 to 1.0 g (more preferably 0.02 to 0.5 g) of the first catalyst per gram of perfluoropolyethersilane present in the fluorine coating liquid.

[0037] In this embodiment, when the glass coating process is performed, the net coating amount of polysilazane on the surface (screen) of the object to be treated is 0.12 g / m 2 The glass coating solution is applied so that the amount of polysilazane applied to the surface of the workpiece by carrying out the glass coating process is 0.02 g / m 2 or more (more preferably 0.05 to 0.3 g / m 2 ) has been confirmed to be preferable.

[0038] In this embodiment, the water treatment step is carried out after the glass coating step, but the water treatment step is not an essential step in the treatment method of the present invention.

[0039] However, it has been confirmed that by carrying out the water treatment step, a uniform glass coating can be formed on the surface of the object to be treated. In particular, it has been confirmed that if a metal catalyst such as a metal carboxylate, an acetylacetonate complex, or metal fine particles is selected as the second catalyst when carrying out the water treatment step in the treatment method of the present invention, an even more uniform glass coating can be formed. The amount of water applied to the surface of the object to be treated during the water treatment step is 1 to 200 g / m. 2 (More preferably 5 to 50 g / m 2 ) has been confirmed to be preferable.

[0040] Furthermore, in this embodiment, when the fluorine coating step is performed, the net coating amount of perfluoropolyether silane on the surface (screen) of the object to be treated is 0.35 g / m 2 The fluorine coating solution is applied to the surface of the workpiece so that the amount of perfluoropolyether silane applied to the surface of the workpiece by carrying out the fluorine coating step is 0.07 g / m 2 or more (more preferably 0.1 to 0.7 g / m 2 ) has been confirmed to be preferable.

[0041] The present invention can be embodied in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments (examples) are merely illustrative in all respects and should not be interpreted as limiting. The scope of the present invention is defined by the claims and is not limited in any way by the text of the specification. Furthermore, all modifications and variations within the equivalent scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0042] The present invention can be suitably used as a means for imparting water repellency and oil repellency to the surface of an object to be treated.

Claims

1. A surface treatment method for forming a water-repellent and oil-repellent coating on a surface of a workpiece, comprising: On the surface of the object to be treated, a glass coating step of applying a glass coating liquid containing polysilazane and a metal catalyst for accelerating a curing reaction of the polysilazane; a fluorine coating step of applying a fluorine coating liquid containing perfluoropolyether silane; Execute the following in order, The surface treatment method further comprises, after the glass coating step and before the fluorine coating step, carrying out a water treatment step of adding moisture to the surface of the object to be treated, on which the glass coating liquid has been applied, by wiping the surface with a cloth soaked in water.

2. The surface treatment method according to claim 1, The surface treatment method comprises applying water to the surface of the object to be treated in an amount of 1 to 200 g / m 2 during the water treatment step.

3. The surface treatment method according to claim 1 or 2, The surface treatment method further comprises blending a first catalyst into the fluorine coating solution during the fluorine coating step to promote the formation of a coating film of perfluoropolyether silane.

4. In the surface treatment method according to claim 3, A surface treatment method using trifluoroacetic acid as a first catalyst.

5. In the surface treatment method according to claim 1, A surface treatment method using a metal carboxylate, an acetylacetonate complex, or metal fine particles as a metal catalyst.