Surface treatment method, surface treatment kit, and surface-treated product

Abstract

An object of the present invention is to provide a novel surface treatment method capable of imparting antibacterial properties or antiviral properties to a surface of a treatment target, a surface treatment kit, and a surface-treated product.SOLUTION: A first step of applying a first liquid agent 11 containing colloidal silica to the surface of an object 10 to be treated and a second step of applying a second liquid agent 12 containing a silane coupling agent having an antibacterial or antiviral functional group to the surface of the object 10 to be treated after the execution of the first step are executed to form a coating film having antibacterial or antiviral properties on the surface of the object 10 to be treated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a surface treatment method for forming a functional coating having antibacterial or antiviral properties on the surface of an object to be treated, a surface treatment kit, and a surface-treated object. [Background technology]

[0002] Recently, antibacterial coating treatments (or antiviral coating treatments) using silane coupling agents having antibacterial (or antiviral) functional groups have become common as a means for imparting antibacterial or antiviral properties to the surface of a treated object for a long period of time (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-214362 Summary of the Invention [Problem to be solved by the invention]

[0004] If the object to be treated is an inorganic material such as glass or metal, this type of silane coupling agent is applied to the surface and then bonds through a silane coupling reaction, thereby enabling the stable formation of an antibacterial (or antiviral) functional coating on the surface of the object to be treated.

[0005] However, this type of silane coupling agent has the property that it is difficult to form a stable functional coating layer when the object to be treated is a plastic material or a painted surface.

[0006] The present invention was completed in view of technical challenges, and aims to provide a novel surface treatment method, a surface treatment kit, and a surface-treated object that can impart antibacterial or antiviral properties to the surface of an object to be treated. [Means for solving the problem]

[0007] The surface treatment method of the present invention for solving the above-mentioned technical problems is a method for forming a functional coating having antibacterial or antiviral properties on the surface of a workpiece, and is characterized by carrying out a first step of applying a first liquid agent containing colloidal silica to the surface of the workpiece, and a second step of applying a second liquid agent containing a silane coupling agent having an antibacterial or antiviral functional group to the surface of the workpiece after carrying out the first step (hereinafter referred to as the "treatment method of the present invention").

[0008] In the treatment method of the present invention, it is preferable to further carry out a third step of applying a third liquid agent containing a silane coupling agent having an organic fluorine-based compound group to the surface of the workpiece after the second step.

[0009] In the treatment method of the present invention, a preferred embodiment is to apply a first liquid agent in which the solid content concentration of colloidal silica has been adjusted to 0.05 to 0.3% by weight when the first step is carried out.

[0010] In the treatment method of the present invention, a mixture of water and alcohol is preferably used as a diluent for adjusting the concentration of the first liquid agent.

[0011] In the treatment method of the present invention, a preferred embodiment is to use a diluent containing an alcohol in an amount of 10% by weight or more and less than 60% by weight.

[0012] The surface treatment kit of the present invention, which solves the above-mentioned technical problems, is a kit for forming a functional coating having antibacterial or antiviral properties on the surface of a treatment target, and is characterized by comprising a first liquid agent containing colloidal silica and a second liquid agent containing a silane coupling agent having an antibacterial or antiviral functional group (hereinafter referred to as the "treatment kit of the present invention").

[0013] In a preferred embodiment of the treatment kit of the present invention, the average primary particle size of the colloidal silica contained in the first liquid agent is 10 nm or less.

[0014] In the treatment kit of the present invention, the colloidal silica contained in the first liquid agent is preferably an ammonia-stable type.

[0015] In the treatment kit of the present invention, the functional group is a quaternary ammonium salt in a preferred embodiment.

[0016] The surface-treated article of the present invention, which solves the above-mentioned technical problems, is an article having a coating having antibacterial or antiviral properties formed on its surface, and is characterized by comprising a silica coating layer resulting from colloidal silica formed on the surface of the article to be treated, and a layer of antibacterial or antiviral functional groups silane-coupled to the silica coating (hereinafter referred to as the "treated article of the present invention"). [Effects of the Invention]

[0017] According to the present invention, it is possible to impart antibacterial or antiviral properties to the surface of an object to be treated. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing a processed product of the present invention according to a first embodiment and a cross-sectional view schematically showing the surface state. [Figure 2] 2(a) to 2(c) are perspective views showing the execution of the treatment method of the present invention according to the first embodiment and cross-sectional views schematically showing the surface state. [Figure 3] FIG. 3 is a perspective view showing a processed product of the present invention according to the second embodiment and a cross-sectional view schematically showing the surface state. [Figure 4] 2(a) to 2(d) are perspective views showing the execution of the treatment method of the present invention according to the first embodiment and cross-sectional views schematically showing the surface state. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to this embodiment.

[0020] <Embodiment 1> -Processed product of the present invention 1- As shown in FIG. 1, the treated object 1 of the present invention according to the first embodiment comprises a silica coating layer 2 resulting from colloidal silica formed on the surface of the object 10 to be treated, and a layer 3 of antibacterial or antiviral functional groups silane-coupled to the silica coating layer 2.

[0021] - Treatment kit of the present invention - The treatment kit of the present invention is for forming a coating having antibacterial or antiviral properties on the surface of the object to be treated 10, and includes a "first liquid agent (11)" and a "second liquid agent (12)" as shown in FIG. 2.

[0022] First Liquid 11 The first liquid 11 contains colloidal silica. In the present invention, colloidal silica refers to fine particles of silica (silicon dioxide: SiO2) dispersed in a solvent such as water or alcohol. In this embodiment, the first liquid 11 was obtained by dissolving commercially available colloidal silica (Snowtex manufactured by Nissan Chemical Industries, Ltd., product name: ST-NXS, solid content: 15% by weight) in a solvent (a 1:1 mixture of water and denatured alcohol (85% ethanol, 10% propanol, 5% isopropyl alcohol) so that the solid content was 0.15% by weight.

[0023] Second liquid 12 The second liquid agent 12 contains a silane coupling agent (hereinafter referred to as the "functional silane coupling agent") having an antibacterial or antiviral functional group. Generally, "antibacterial" refers to the property of inhibiting the growth of specific bacteria present on the surface of the workpiece 10, and "antiviral" refers to the property of reducing specific viruses present on the surface of the workpiece 10. Therefore, in the present invention, the functional silane coupling agent refers to a compound having a structure in which a silyl group (including a silyl group derivative) is bonded to the end of a functional group having at least one of the antibacterial and antiviral properties. In this embodiment, a functional silane coupling agent (trade name: KBM-9418-40, manufactured by Shin-Etsu Chemical Co., Ltd.) having a silyl group bonded to the end of a quaternary amine salt as the functional group was used. The second liquid agent 12 was obtained by dissolving the functional silane coupling agent in a 1:1 mixture of water and denatured alcohol (85% ethanol, 10% propanol, 5% isopropyl alcohol) to a blending amount of 4 wt % (net amount of the functional silane coupling agent).

[0024] -Processing method of the present invention- Hereinafter, the treatment kit of the present invention is used to carry out the treatment method of the present invention for forming a coating having antibacterial or antiviral properties on the surface of the treatment object 10. The treatment method of the present invention carries out a "first step" and a "second step."

[0025] ·First process In the first step, a first liquid agent 11 is applied to the surface of the workpiece 10. As shown in FIG. 2(a), in this embodiment, a smartphone (screen size: 6.1 inches) with a fluorine coating 5 on the screen was used as the workpiece 10. As shown in FIG. 2(b), the first step was performed by dropping 0.5 ml of the first liquid agent 11 onto the surface (screen) of the workpiece 10, and then spreading and wiping it with a nonwoven fabric (W). By performing the first step, a silica coating layer 2 resulting from colloidal silica is formed on the surface of the workpiece 10.

[0026] ·Second process In the second step, a second liquid agent 12 is applied to the surface of the workpiece 10 (which has been subjected to the first step). As shown in FIG. 2(c), in this embodiment, the net amount of the functional silane coupling agent applied to the surface (screen) of the workpiece 10 is 50 g / m 2 After the second liquid agent 12 was applied to the surface of the object to be treated 10 so as to achieve the above, the second step was carried out by wiping the surface up while spreading it with a nonwoven fabric (W).

[0027] It was confirmed that the second step resulted in the stable formation of a layer 3 of functional groups resulting from the functional silane coupling agent on the surface of the workpiece 10. This is presumably because the silyl groups of the functional silane coupling agent bond to the layer 2 of silica coating formed on the surface of the workpiece 10 by the silane coupling reaction. That is, in the treatment method of the present invention, the layer 2 of silica coating is formed (precoated) on the surface of the workpiece 10 by performing the first step, and therefore the layer 3 of functional groups can be stably formed by performing the subsequent second step. As a result, the treatment method of the present invention can be performed regardless of the material of the workpiece 10.

[0028] Furthermore, the surface of the treated object 1 of the present invention, which has been surface treated by the treatment method of the present invention, is endowed with antibacterial or antiviral properties for a long period of time by the layer 3 of functional groups.

[0029] Furthermore, the processing method of the present invention can be carried out in a relatively safe working environment because relatively safe solvents such as water or alcohol can be used as diluents to prepare the surface treatment solvent used in the first step.

[0030] [Examples 1 to 9] A first liquid formulation was obtained in the same manner as in the above embodiment (Example 1 in the examples below), except that the colloidal silica used to prepare the first liquid formulation was one of the product names shown in Table 1 below.

[0031] [Table 1]

[0032] When the processing method of the present invention was carried out using the first liquid agent according to each example in the same steps as in the embodiment, it was confirmed that a layer of functional groups was stably formed in all cases.

[0033] Furthermore, it was confirmed that the smaller the colloidal silica particle size, the more stable the formation of the functional group layer. This is likely due to the fact that the smaller the colloidal silica particle size, the denser the silica film formed. This tendency was particularly pronounced when the surface of the treated object was coated with fluorine, as used in the embodiment. This is presumably because, during the first step of the treatment method of the present invention, the colloidal silica particles become embedded in the gaps between the organic fluorine-based compounds that grow on the smartphone screen, forming a denser silica film. Therefore, in the present invention, it is preferable to use colloidal silica with an average primary particle size of 10 nm or less.

[0034] Furthermore, it was confirmed that when ammonia-stable colloidal silica was used, the layer of functional groups was formed more stably. This is probably because, when the first step of the treatment method of the present invention is carried out, the ammonia content of the ammonia-stable colloidal silica volatilizes, forming a silica coating with higher purity.

[0035] For this reason, in the present invention, it is preferable to use ammonia-stable colloidal silica.

[0036] [Examples 10 to 12] A first liquid preparation was obtained in the same manner as in the embodiment (i.e., Example 1), except that the concentration of colloidal silica contained in the first liquid preparation was as shown in Table 2 below.

[0037] [Table 2]

[0038] When the treatment method of the present invention was carried out using the first liquid agent according to each example in the same steps as in the embodiment, it was confirmed that a layer of functional groups was stably formed.

[0039] Furthermore, it was confirmed that the higher the concentration of colloidal silica contained in the first liquid, the more stable the layer of functional groups formed. This is probably because the higher the concentration of colloidal silica, the thicker the silica film formed.

[0040] However, it has also been confirmed that if the concentration of colloidal silica contained in the first liquid agent becomes extremely high, the silica coating formed may become uneven and discoloration may occur on the surface of the object to be treated.

[0041] Therefore, in the present invention, it is a preferred embodiment that when the first step is carried out, the first liquid agent in which the solid content concentration of colloidal silica is adjusted to 0.05 to 0.3% by weight is applied.

[0042] [Examples 13 to 15] A first liquid preparation was obtained in the same manner as in the embodiment (i.e., Example 1), except that the diluent for preparing the first liquid preparation was one having the components shown in Table 3 below.

[0043] [Table 3]

[0044] When the treatment method of the present invention was carried out using the first liquid agent according to each example in the same steps as in the embodiment, it was confirmed that a layer of functional groups was stably formed.

[0045] It was also confirmed that the greater the proportion of alcohol contained in the diluent, the more improved the wettability of the first liquid agent during the first step of the treatment method of the present invention, and the more efficient the work.

[0046] However, since the first liquid agent is designated as a hazardous material if the proportion of alcohol contained in the diluent exceeds 60% by weight, a preferred embodiment of the present invention is to use a diluent having an alcohol mixing proportion of 10% by weight or more and less than 60% by weight. Note that it is preferable to use a linear or branched alcohol having 1 to 3 carbon atoms as the alcohol.

[0047] In the present embodiment, the second liquid agent is a solution of a functional silane coupling agent in which a silyl group is bonded to the terminal of a quaternary amine salt as a functional group, but the functional group in the present invention is not particularly limited as long as it has antibacterial or antiviral properties. Other examples of the functional group include primary to tertiary ammonium groups.

[0048] In the second step of the present invention, a catalyst may be added to the second solution to promote film formation. Examples of such catalysts include organic acids such as trifluoroacetic acid and inorganic acids.

[0049] <Embodiment 2> -Processed product of the present invention 1- 3, the treated product 1 of the present invention according to the second embodiment includes a silica coating layer 2, a silica functional group layer 3, and an organic fluorine-based compound group layer 4. The silica coating layer 2 and the functional group layer 3 in this embodiment are the same as those described in the first embodiment, and therefore will not be described again to avoid repetition.

[0050] - Treatment kit of the present invention - The treatment kit of the present invention is intended to form a coating having antibacterial or antiviral properties on the surface of the object to be treated 10, as well as to impart water repellency and oil repellency, and includes a first liquid agent 11, a second liquid agent 12, and a "third liquid agent (13)" as shown in Figure 4. Note that the first liquid agent 11 and the second liquid agent 12 in this embodiment are the same as those described in the first embodiment, and therefore description thereof will be omitted here to avoid repetition.

[0051] Third liquid 13 The third liquid agent 13 contains a silane coupling agent having an organic fluorine-based compound group. In the present invention, the silane coupling agent having an organic fluorine-based compound group refers to a compound having a structure in which a silyl group (including a silyl group derivative) is bonded to the end of an organic fluorine-based compound group such as a perfluoroalkyl group or a perfluoropolyether group. In this embodiment, a commercially available perfluoropolyether silane (manufactured by Unichem Co., Ltd., product name: UEC-001M) was used and dissolved in a solvent (hydrofluoroether) to give a blending amount of 1.0 wt % (net amount of perfluoropolyether silane), thereby obtaining the third liquid agent 13.

[0052] -Processing method of the present invention- Hereinafter, the treatment method of the present invention is carried out using the treatment kit of the present invention to form a coating having antibacterial or antiviral properties on the surface of the workpiece 10 and to impart water repellency and oil repellency. The treatment method of the present invention carries out a first step, a second step, and a "third step." Note that the first and second steps in this embodiment are the same as those described in the first embodiment, and therefore will not be described here to avoid repetition.

[0053] ·Third process In the third step, a third liquid agent containing a silane coupling agent having an organic fluorine-based compound group is applied to the surface of the workpiece 10 after the second step has been performed. As shown in Fig. 4(d), in this embodiment, the net amount of perfluoropolyether silane applied to the surface (face) of the workpiece 10 is 0.35 g / m 2 After the third liquid agent 13 was applied to the surface of the object to be treated 10 so as to be as shown in the figure, the third step was carried out by wiping the surface up while spreading it with a nonwoven fabric (W).

[0054] It was confirmed that the execution of the third step resulted in the stable formation of an organic fluorine compound layer 4 on the surface of the workpiece 10. At this stage, it is unclear whether the organic fluorine compound layer 4 is simply laminated on the functional group layer 3 or whether it is bonded to the silica coating layer 3 formed on the surface of the workpiece by a silane coupling reaction.

[0055] However, it has been confirmed that the surface of the treated object 1 of the present invention, which has been surface treated by the treatment method of the present invention in which the third step has been carried out, is imparted with water repellency and oil repellency, resulting in good anti-fouling properties.

[0056] In this embodiment, a perfluoropolyether silane solution is used as the second liquid agent, but the silane coupling agent having an organic fluorine-based compound group contained in the second liquid agent is not limited to perfluoropolyether silane. It has been confirmed that similar results can be obtained when the same process as in the embodiment is carried out using, for example, perfluoroalkylsilane as the silane coupling agent having an organic fluorine-based compound group.

[0057] However, since the coefficient of friction of a perfluoropolyether silane coating is lower than that of a perfluoroalkyl silane coating, the surface of an object treated with perfluoropolyether silane exhibits good finger slipperiness. Therefore, when the treatment method of the present invention is applied to a smartphone or car navigation system that inputs commands by sliding a finger across the screen, such as flicking or swiping, it is preferable to use perfluoropolyether silane as a silane coupling agent having an organic fluorine-based compound group.

[0058] It has also been confirmed that if the molecular weight or concentration of the silane coupling agent contained in the third liquid agent increases, water repellency and oil repellency improve, but unevenness occurs and the durability of the coating film decreases. Therefore, it has been confirmed that the molecular weight of the silane coupling agent contained in the second liquid agent is preferably 1500 to 6000 (more preferably 3000 to 5000), and the amount of silane coupling agent contained in the second liquid agent is preferably 0.05 to 5.0 wt% (more preferably 0.1 to 2.0 wt%).

[0059] In the third step of the present invention, a catalyst may be added to the third solution to promote film formation. Examples of such catalysts include organic acids such as trifluoroacetic acid and inorganic acids.

[0060] 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]

[0061] The present invention can be suitably used as a means for imparting antibacterial or antiviral properties to the surface of an object to be treated. [Explanation of symbols]

[0062] 1. Treated product of the present invention 2 layers of silica coating 3. Functional functional group layer 4. Organic fluorine compound layer 10. Material to be processed 11 First Liquid 12 Second liquid 13 Third liquid

Claims

1. A surface treatment method for forming a functional coating having antibacterial or antiviral properties on a surface of a treatment object, comprising: a first step of applying a first liquid agent containing colloidal silica to a surface of an object to be treated; a second step of applying a second liquid agent containing a silane coupling agent having an antibacterial or antiviral functional group to the surface of the object to be treated after the first step is performed; A surface treatment method characterized by carrying out the steps of:

2. The surface treatment method according to claim 1, The surface treatment method further includes a third step of applying a third liquid agent containing a silane coupling agent having an organic fluorine-based compound group to the surface of the object to be treated after the second step has been performed.

3. The surface treatment method according to claim 1, A surface treatment method in which, when the first step is carried out, a first liquid agent having a solid content concentration of colloidal silica adjusted to 0.05 to 0.3 wt % is applied.

4. The surface treatment method according to claim 3, A surface treatment method using a mixture of water and alcohol as a diluent to adjust the concentration of the first liquid agent.

5. The surface treatment method according to claim 4, A surface treatment method using a diluent containing an alcohol in an amount of 10% by weight or more and less than 60% by weight.

6. A surface treatment kit for forming a functional coating having antibacterial or antiviral properties on the surface of a treatment object, a first liquid agent containing colloidal silica; a second liquid agent containing a silane coupling agent having an antibacterial or antiviral functional group; A surface treatment kit comprising:

7. The surface treatment kit according to claim 6, A surface treatment kit, wherein the colloidal silica contained in the first liquid agent has an average primary particle diameter of 10 nm or less.

8. The surface treatment kit according to claim 6, A surface treatment kit in which the colloidal silica contained in the first liquid agent is an ammonia-stable type.

9. The surface treatment kit according to claim 6, A surface treatment kit in which the functional group is a quaternary ammonium salt.

10. A surface-treated object having an antibacterial or antiviral coating formed on its surface, a silica coating layer resulting from colloidal silica formed on the surface of the workpiece; a layer of antibacterial or antiviral functional groups silane-coupled to the silica coating; A surface-treated product characterized by comprising:

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