JP3191259B2 - Method of making substrate surface hydrophilic - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a coating film for making a surface of a substrate having a surface made of resin highly hydrophilic.

[0002]

2. Description of the Related Art When a substrate surface is hydrophilized, attached water droplets spread evenly on the substrate surface, so that fogging of glass, lenses and mirrors can be effectively prevented, and devitrification due to moisture is prevented. ,
Useful for ensuring visibility in rainy weather. Further, hydrophobic contaminants such as urban dust, combustion products such as carbon black contained in exhaust gas of automobiles, oils and fats, and sealant eluting components are hardly adhered. It is convenient because it can be dropped more easily.

Under these circumstances, hydrophilic resins have been proposed in the field of antifogging paints and exterior antifouling paints in particular (for example, Japanese Utility Model Laid-Open No. 5-68006, "Polymer", Vol. May 1995, p. 307). Also, a surface treatment method for making the surface hydrophilic has been proposed (for example, Japanese Utility Model Laid-Open No. 3-129357).

[0004] However, the conventionally proposed hydrophilic resin can be made hydrophilic only up to about 30 to 50 ° in terms of the contact angle with water, and cannot exhibit a sufficient fogging prevention effect.
In addition, adhesion of contaminants composed of inorganic clay, rainfall, and cleanliness by water washing are not sufficient. In the surface treatment methods (hydrophobic treatment, etching treatment, plasma treatment, etc.) that have been conventionally proposed, the state cannot be maintained for a long time even if the surface can be temporarily made highly hydrophilic.

The present inventor has proposed PCT / JP96 / 0073.
In No. 3, when a photocatalyst containing layer is formed on the substrate surface,
Invented that the surface was highly hydrophilized to 10 ° or less in terms of the contact angle with water in response to the photoexcitation of the photocatalyst. This technology was applied to various materials such as glass, lenses, mirrors, exterior materials, and plumbing materials. When applied to composites, these composites have excellent anti-fog,
It was proposed that functions such as antifouling can be provided. According to this method, since it is highly hydrophilized up to 10 ° or less in terms of the contact angle with water, a sufficient anti-fogging effect is exhibited, adhesion of inorganic clay-based contaminants, rainfall, and water washing. And the cleanliness of the device is greatly improved. In addition, the state of hydrophilization is maintained and restored in response to the photoexcitation of the photocatalyst.

[0006]

SUMMARY OF THE INVENTION PCT / JP96 / 0
No. 0733 discloses an example of a composite material in which a surface layer composed of a photocatalyst and a silicon resin in which at least a part of an organic group bonded to a silicon atom is substituted with a hydroxyl group is formed on a resin base material such as an acrylic resin. Although the composite material surface layer produced by the method disclosed therein certainly exhibits a high degree of hydrophilicity in response to photoexcitation of the photocatalyst, the abrasion resistance was about H in pencil hardness. In view of the above, the present invention provides a method for hydrophilizing a resin substrate having better abrasion resistance while maintaining a degree of hydrophilization according to photoexcitation of a photocatalyst in a surface layer formed on the resin substrate. The purpose is to:

[0007]

According to the present invention, in order to achieve the above object, a step of subjecting a surface of a base material having a surface made of a resin to a hydrophilic treatment, and the step of including a photocatalyst and a silicone resin on the surface. Providing a method for hydrophilizing the surface of a substrate, comprising: a step of coating with a layer; and a step of replacing at least a part of an organic group bonded to a silicon atom in the silicone resin with a hydroxyl group. . A step of coating the surface with a layer containing a photocatalyst and a silicone resin;
The substrate can be made hydrophilic by the step of substituting at least a part of the organic group bonded to the silicon atom in the silicone resin in the layer containing the hydroxy resin with a hydroxyl group. Further, by subjecting the surface of the base material to a hydrophilic treatment, the surface layer can be firmly fixed to the base material. As the hydrophilic treatment method, it is convenient and preferable to use a discharge treatment, an alkali treatment, or a step of irradiating a photocatalyst with light containing photons having energy capable of exciting the photocatalyst while contacting the photocatalyst.

In a preferred aspect of the present invention, a step of subjecting a substrate surface having a resin surface to a hydrophilic treatment, a step of coating the surface with a layer containing a photocatalyst and a silicone resin, Substituting at least a part of an organic group bonded to a silicon atom therein with a hydroxyl group, and irradiating light containing photons having energy capable of exciting the photocatalyst to form an adsorbed water layer on the substrate surface And to include. After performing a step of substituting at least a part of the organic group bonded to the silicon atom in the silicone resin with a hydroxyl group, the substrate is irradiated with light containing photons having energy capable of exciting the photocatalyst, and is adsorbed on the surface of the base material. By forming the water layer, the surface is highly hydrophilized to 10 ° or less, and more surprisingly, the hydrophilicity of the surface of the sample subjected to this treatment exhibits a hydrophilic retention of about 3 weeks even in a dark place. .

In a preferred embodiment of the present invention, instead of the step of hydrophilically treating the surface of the substrate, a corona discharge treatment or an ultraviolet treatment such as irradiation with a mercury lamp is applied after the step of coating with a layer containing a photocatalyst and a silicone resin. Process. Even in this case, the adhesion can be improved. In addition, since the photocatalyst can be excited by ultraviolet rays, the step of substituting at least a part of the organic group bonded to the silicon atom in the silicone resin with a hydroxyl group and the step of forming an adsorbed water layer on the surface of the base material are simultaneously performed. It is also possible to have it done.

[0010] In a preferred aspect of the present invention, the step of substituting at least a part of the organic group bonded to the silicon atom in the silicone resin with a hydroxyl group includes the step of: Is preferably a step of irradiating light containing photons having energy capable of exciting the light without the need of a special device because the light can be replaced only by the excitation light source or natural light.

[0011] In a preferred aspect of the present invention, the step of substituting at least a part of the organic group bonded to the silicon atom in the silicone resin with a hydroxyl group includes the step of corona-coating the layer containing the photocatalyst and the silicone resin. It is preferable that the discharge process is performed because the time required for the replacement process can be reduced by the discharge process. However,
In order to highly hydrophilize to less than 10 °, it is necessary to further irradiate light containing photons having energy capable of exciting the photocatalyst.

In a preferred embodiment of the present invention, the step of coating the substrate with an acrylic resin, and coating the layer with the layer containing the photocatalyst and the silicone resin comprises the steps of: organoalkoxysilane, a hydrolyzate thereof, and a dehydration-condensation polymer thereof. At least one of
Mixing the seed-containing film-forming element and the photocatalyst particles,
The method includes a step of applying the mixture and a step of heat-curing the film-forming element, and the heat-curing is performed at 90 ° C. or lower. By performing the heat curing at 90 ° C. or lower, the dimensional stability of the acrylic resin is improved.

In another aspect of the present invention, a step of subjecting a substrate surface having a surface made of resin to hydrophilic treatment, a step of coating the surface with a layer containing a photocatalyst and amorphous silica,
And a method for hydrophilizing the surface of a substrate, characterized by comprising: In addition, by performing hydrophilic treatment on the substrate surface, the adhesion between the hydrophilic surface layer composed of photocatalyst particles and amorphous silica and the substrate surface is improved, so that the surface layer can be firmly fixed to the substrate. Become. As the hydrophilic treatment method, it is convenient to use a discharge treatment, an alkali treatment, a coating of a hydrophilic intermediate layer, or a step of irradiating light containing photons having energy capable of exciting the photocatalyst while contacting the photocatalyst. Yes and preferred.

In a preferred embodiment of the present invention, the step of hydrophilically treating the surface of the substrate having the surface made of resin, the step of coating the surface with a layer containing a photocatalyst and amorphous silica, and the step of exciting the photocatalyst Irradiating light containing photons having energy to form an adsorbed water layer on the substrate surface. By irradiating light containing photons having energy capable of exciting the photocatalyst to form an adsorbed water layer on the surface of the substrate, the surface is highly hydrophilized to 10 ° or less. The hydrophilicity of the surface of the sample subjected to the method exhibits a hydrophilic maintenance property for one week or more even in a dark place.

In a preferred embodiment of the present invention, instead of the step of hydrophilically treating the surface of the substrate, a corona discharge treatment or an ultraviolet treatment such as irradiation with a mercury lamp is applied after the step of coating with a layer containing a photocatalyst and amorphous silica. Perform the process. Even in this case, the adhesion can be improved. Further, since the photocatalyst can be excited by ultraviolet rays, the step of forming an adsorbed water layer on the substrate surface can be performed at the same time.

In a preferred aspect of the present invention, the step of coating the substrate with an acrylic resin and coating the layer with the photocatalyst and amorphous silica comprises the steps of: organoalkoxysilane, silanol as a hydrolyzate thereof; Mixing a film-forming element containing at least one of dehydrated polycondensate, such as organosilicate and polysilanol, with photocatalyst particles; applying the mixture; and heat-curing the film-forming element. And said heat curing is 9
It should be performed at 0 ° C. or lower. By performing the heat curing at 90 ° C. or lower, the dimensional stability of the acrylic resin is improved.

In a preferred embodiment of the present invention, at least the surface of the base material is made of a vinyl chloride resin, and the step of coating with a layer containing the photocatalyst and amorphous silica includes the step of: Mixing a film-forming element containing at least one polycondensate with photocatalyst particles, applying the mixture, and heat-curing the film-forming element, and wherein the heat-curing is performed at 60 ° C. I will do it below. Performing the heat curing at 60 ° C. or less can prevent deterioration during the production of the vinyl chloride resin and improve dimensional stability.

[0018]

Next, the components of the present invention will be described. The substrate having a surface made of a resin includes any of a resin itself, a substrate whose surface is coated with a resin, and a composite material whose surface layer is made of a resin layer. Typical examples of the resin itself include film base materials such as a shatterproof film, a design film, and a corrosion-resistant film; and resin base materials such as signboards and soundproof walls of expressways. Examples of the base material whose surface is coated with a resin include a painted plate of an automobile housing, a painted building material, a laminated plate having a resin film adhered to the surface, a base material treated with a primer, and a hard coat treatment. Substrates and the like are typical examples. As a composite material having a surface layer made of a resin layer, a resin seal material having an adhesive layer provided on a back surface,
A typical example is a reflection mirror.

The term “hydrophilization” as used herein refers to a change in a state in which water wettability is improved. Hydrophobic contaminants such as urban dust, combustion products such as carbon black contained in exhaust gas from automobiles, oils and fats, and sealant eluting components are unlikely to adhere.
In order to allow the substrate surface to be easily dropped by rainfall or washing with water even if it adheres, the surface of the substrate is preferably hydrophilized to a contact angle with water of 50 ° or less, more preferably about 30 ° or less.
Further, in order to prevent the inorganic clay contaminants from adhering easily and to be easily dropped by rainfall or washing with water, the surface of the base material is preferably 10 ° or less in terms of a contact angle with water, more preferably 5 ° or less.゜ It is preferable that the surface is highly hydrophilized to the extent of less than about. In order to uniformly spread water droplets attached to the surface of the transparent substrate, effectively prevent fogging of glass, lenses and mirrors, prevent devitrification due to moisture, and ensure visibility in rainy weather, It is preferable that the surface of the base material is highly hydrophilic to about 10 ° or less.

The term "photocatalyst" as used herein means a photocatalyst capable of replacing an organic group bonded to a silicon atom of a silicone resin with a hydroxyl group by a reaction through holes or conduction electrons generated by photoexcitation of electrons in a valence band. And / or a substance having an ability to form an adsorbed water layer by imparting polarity, and more specifically, an anatase type titanium oxide, a rutile type titanium oxide, a tin oxide, a zinc oxide, a bismuth trioxide , Tungsten trioxide, ferric oxide, strontium titanate and the like can be used.

The term "silicon resin" as used herein means a resin formed by hydrolysis and dehydration-condensation polymerization of a film-forming element containing at least one of an organoalkoxysilane, a hydrolyzate thereof, and a dehydration-condensation polymer thereof. As expected. Here, as the organoalkoxysilane, methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltri-t-butoxysilane, ethyltrichlorosilane, ethyltribromosilane, ethyltrichlorosilane Methoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltri-t-butoxysilane, n
-Propyltrichlorosilane, n-propyltribromosilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltriisopropoxysilane, n-propyltri-t-butoxysilane, n-
Hexyltrichlorosilane, n-hexyltribromosilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltriisopropoxysilane, n-hexyltri-t-butoxysilane, n-decyltrichlorosilane, n-decyl Tribromosilane,
n-decyltrimethoxysilane, n-decyltriethoxysilane, n-decyltriisopropoxysilane, n-
Decyltri-t-butoxysilane, phenyltrichlorosilane, phenyltribromosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, phenyltri-t-butoxysilane, tetrachlorosilane, tetrabromosilane, tetramethoxysilane, Tetraethoxysilane, tetraisopropoxysilane, tetra-t-butoxysilane, dimethoxydiethoxysilane, dimethyldichlorosilane, dimethyldibromosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiisopropoxysilane, dimethyldi-t-butoxysilane , Diphenyldichlorosilane, diphenyldibromosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldiisopropoxy Orchids, diphenyl t- butoxysilane, phenyl methyldichlorosilane, phenyl methyl dibromo silane, phenyl methyl dimethoxy silane,
Phenylmethyldiethoxysilane, phenylmethyldiisopropoxysilane, phenylmethyldi-tert-butoxysilane, trichlorohydrosilane, tribromohydrosilane, trimethoxyhydrosilane, triethoxyhydrosilane, triisopropoxyhydrosilane, tri-t-butoxyhydrosilane, vinyltrichlorosilane , Vinyl tribromosilane, vinyl trimethoxy silane, vinyl triethoxy silane, vinyl triisopropoxy silane,
Vinyl tri-t-butoxysilane, trifluoropropyltrichlorosilane, trifluoropropyltribromosilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltriisopropoxysilane, trifluoropropyltri-t-butoxysilane, γ-glycidoxypropylmethyldichlorosilane, γ-glycidoxypropylmethyldibromosilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyl Diisopropoxysilane, γ-glycidoxypropylmethyldi-t-butoxysilane, γ-methacryloxypropylmethyldichlorosilane, γ-methacryloxypropylmethyldibromosilane, γ Methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropylmethyldiisopropoxysilane, γ-methacryloxypropylmethyldi-t-butoxysilane, γ-aminopropylmethyldi Chlorosilane, γ-aminopropylmethyldibromosilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldiisopropoxysilane, γ-aminopropylmethyldi-t-butoxysilane,
γ-mercaptopropylmethyldichlorosilane, γ-mercaptopropylmethyldibromosilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropylmethyldiisopropoxysilane, γ-mercaptopropylmethyl Di-t-butoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β-
(3,4-epoxycyclohexyl), γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrichlorosilane, γ-glycidoxypropyltribromosilane, γ-glycidoxypropyltrimethoxysilane, γ- Glycidoxypropyltriisopropoxysilane, γ-glycidoxypropyltri-t-butoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltrichlorosilane,
γ-methacryloxypropyltribromosilane, γ-
Methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriisopropoxysilane, γ
-Methacryloxypropyltri-t-butoxysilane,
γ-aminopropyltriethoxysilane, γ-aminopropyltrichlorosilane, γ-aminopropyltribromosilane, γ-aminopropyltrimethoxysilane, γ
-Aminopropyltriisopropoxysilane, γ-aminopropyltri-t-butoxysilane, and mixtures thereof can be used.

The method of coating the substrate surface with a layer containing a photocatalyst and a silicone resin includes photocatalyst particles or a photocatalyst sol, and at least one of the above-mentioned organoalkoxysilanes, hydrolyzates thereof, and dehydration-condensation polymers thereof. After applying the liquid material prepared by mixing the film forming elements to the surface of the base material, heating,
The hydrolysis of the organoalkoxysilane is completed by means of moisture, ultraviolet rays, or the like, and is cured by dehydration-condensation polymerization. Here, the method of applying the liquid material on the surface of the substrate includes a spray coating method and a flow coating method.
Method, spin coating method, dip coating
A method such as a coating method and a roll coating method can be suitably used.

The amorphous silica referred to here is obtained by hydrolysis and dehydration condensation of a film-forming element containing at least one of a tetraalkoxysilane and / or an alkyl silicate, a hydrolyzate thereof, and a dehydration condensation polymer thereof. What is formed can be suitably used. Here, as tetraalkoxysilane, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane,
Diethoxydimethoxysilane and the like can be suitably used. As the alkyl silicate, the average composition formula SiO
Those satisfying _m (OR) _n (R is one or more organo groups) can be suitably used.

The photon having energy capable of exciting the photocatalyst is a photon having energy (ie, shorter wavelength) than the energy gap between the conduction electron band and the valence band of the photocatalytic crystal. More specifically, when the photocatalyst is an anatase type titanium oxide, the wavelength is 387n.
m or less, in the case of rutile type titanium oxide, wavelength 413 nm
Hereinafter, the photon has a wavelength of 344 nm or less in the case of tin oxide and 387 nm or less in the case of zinc oxide.

The light containing photons having energy capable of exciting the photocatalyst is light emitted from a light source containing photons of the above wavelength. In the case of the photocatalyst, since it is excited by an ultraviolet light source, the light source is a fluorescent lamp, an incandescent lamp, a metal halide lamp, indoor lighting such as a mercury lamp, sunlight, or a light source of such a light source guided by a low-loss fiber. A light source or the like can be used.

The hydrophilic treatment of the surface of the substrate having the surface made of resin is intended to enhance the adhesion between the substrate surface and the layer containing the photocatalyst and the silicone resin, and the degree of hydrophilicity is determined by the contact angle with water. The conversion is performed up to about 50 ° or less, more preferably about 20 ° or less.

The hydrophilic treatment of the surface of the base material can be performed by a discharge treatment, an alkali treatment, a step of irradiating light containing photons having energy capable of exciting the photocatalyst while contacting the photocatalyst, or the like. Here, corona discharge treatment, plasma discharge treatment and the like can be suitably used for the discharge treatment. The alkali treatment can be performed by bringing the base material into contact with an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, or the like. The step of irradiating light containing photons having energy capable of exciting the photocatalyst while contacting the photocatalyst is performed by applying a method such as applying a photocatalyst sol to a base material or immersing the base material in the photocatalyst sol. The irradiation can be performed by irradiating light containing photons having energy capable of exciting the photocatalyst.

The ultraviolet treatment according to claims 4 and 5 is performed by irradiating the surface of the sample with ultraviolet irradiation means having a higher illuminance than the normal use conditions. Preferably 2 mW / cm ² or more, more preferably carried out by irradiating the 10 mW / cm ² or more UV. As the ultraviolet irradiation means, a corona discharge device, a mercury lamp or the like can be suitably used.

The step of substituting at least a part of the organic group bonded to the silicon atom in the silicone resin with a hydroxyl group includes the step of irradiating light containing photons having energy capable of photoexciting the photocatalyst in the coating layer, It can be performed by a discharge treatment. Energy capable of photo-exciting the photocatalyst in the coating layer
When utilizing the step of irradiating light containing photons having a value of 0.01 mW / cm ² or more, more preferably 0.1 mW / cm ² or more.
It is preferable to irradiate the photons of mW / cm ² or more. In addition, a corona discharge device,
The reaction in this step can be accelerated by using a high illuminance ultraviolet illuminance means such as a mercury lamp.

Further irradiation with light containing photons having energy capable of exciting the photocatalyst excites the photocatalyst in the coating layer to form and increase the adsorbed water layer on the surface of the substrate. OH stretch peak in (IR) analysis
Peaks, HOH stretching peaks, and HOH bending peaks increase. The formation and increase of the adsorbed water layer achieves a high degree of hydrophilization of the coating layer surface. The illuminance of photons having energy capable of exciting a photocatalyst necessary for forming and increasing an adsorbed water layer on the surface of the substrate is 0.001 mW / cm.
Realized if there are ^two or more.

[0031]

【Example】

Embodiment 1 FIG. (Effect of Acrylic Substrate and Surface Treatment) First, a primer coating (paint made by Toshiba Silicone, PH93 diluted 6 times with toluene solvent) is spray-coated on a 10 cm square PMMA plate surface. After drying at room temperature, the substrate was covered with a primer resin layer. Next, a silicone hard coating agent (Toshiba, manufactured by Toshiba Silicone Co., Ltd.) was applied by a flow coating method and dried at 120 ° C. for 30 minutes to obtain a # 1 sample. Obtained. Further, using a wire-electrode as an electrode, the gap between the tip of the electrode and the sample surface was 2 mm, the voltage was 26 kV, the frequency was 39 kHz, and the sample feed speed was 4.2 m / using a corona surface treatment device (manufactured by Kasuga Electric). The sample was subjected to a high-frequency corona discharge treatment under the conditions of minutes and a # 2 sample was obtained. The # 1 sample surface was immersed in a 5% aqueous solution of sodium hydroxide for 30 minutes, and after tilting the sample to confirm that the aqueous solution spread on the surface, the sample was washed with water and wiped off water to obtain a # 3 sample. An anatase type titanium oxide sol (Nissan Chemical, T
A-15) was applied, and a light source (black light blue (BLB fluorescent lamp), manufactured by Sankyo Electric Co., Ltd.) having an illuminance of 0.6 mW / cm ² was irradiated for 24 hours. Thereafter, titanium oxide was removed by washing with water, and water was further removed. Was wiped off to obtain a # 4 sample.
On the other hand, 56 parts by weight of an anatase type titanium oxide sol (Nissan Chemical Co., TA-15) and 33 parts by weight of silica sol (Glaska A solution made by Nippon Synthetic Rubber) were mixed and diluted with ethanol.
Further, 11 parts by weight of trimethoxysilane (made by Nippon Synthetic Rubber,
Glasca B solution) was added to prepare a titanium oxide-containing coating composition. The coating composition was used for each of # 1 to # 4 samples,
It was applied by the flow coating method, and was cured by heat treatment at 120 ° C. for 30 minutes to obtain # 5 to # 8 samples. About the obtained sample, the adhesiveness of the coating film and the hydrophilicity by the photoexcitation of the titanium oxide particles were evaluated. Here, the adhesion of the coating film was evaluated based on whether or not the coating film was simultaneously peeled off when the cellophane tape was adhered to one end or the other end of the coating film surface and then quickly peeled off. The hydrophilization of the titanium oxide particles by photoexcitation was examined by the change in the contact angle with water before and after irradiation with a BLB fluorescent lamp having an ultraviolet illuminance of 0.6 mW / cm ² for 48 hours. Here, the contact angle with water was measured 30 seconds after a water droplet was dropped on the sample surface from the micro syringe using a contact angle measuring device (CA-X150, manufactured by Kyowa Interface Chemical Co., Ltd.). Table 1 shows the results. Table 1 shows that the adhesion of the coating film can be improved by the discharge treatment, the alkali treatment, or the photocatalytic treatment (claim 3) without reducing the degree of hydrophilicity.

[0032]

[Table 1]

Embodiment 2 FIG. (Influence of polycarbonate base material and surface treatment) First, a primer coating material (PC-7A, manufactured by Shin-Etsu Silicone Co., Ltd.) was spray-coated on a 10 cm square polycarbonate plate (# 9 sample). After drying at 120 ° C. for 20 minutes, the substrate was covered with a primer-resin layer.
A sample was obtained. Next, a silicone-based hard coating agent (KP-85, manufactured by Shin-Etsu Silicone Co., Ltd.) was applied by a spray coating method, and dried at 120 ° C. for 60 minutes.
Eleven samples were obtained. Also, primer paint (manufactured by Toshiba Silicone, PH91) on a polycarbonate board of 10 cm square.
Is applied at 120 ° C. after spray-coating.
After drying the substrate, the substrate is covered with a primer resin layer, and then a silicon-based hard coating agent (Toshiba Silicon Co., Ltd.)
Co., Ltd., Tosgard) was applied by a spray coating method and dried at 120 ° C. for 60 minutes to obtain a # 12 sample. Further, the surfaces of the # 9 to # 12 samples were subjected to corona discharge treatment under the same conditions as in Example 1 to obtain # 13 to # 16 samples. With respect to the # 9 to # 12 samples and the # 13 to # 16 samples, the contact angle with water on the surface was measured, and the change in water wettability of the samples before and after corona discharge treatment was examined. Table 2 shows the results.
Table 2 shows that the corona discharge treatment improved the water wettability of each sample surface. This is considered to mean that the titanium oxide-containing film has changed to a more suitable state as described later.

[0034]

[Table 2]

On the other hand, 56 parts by weight of an anatase type titanium oxide sol (Nissan Chemical Co., Ltd., TA-15) and 33 parts by weight of silica sol (Glaska A solution made by Nippon Synthetic Rubber Co., Ltd.) were mixed and mixed with ethanol.
After dilution with toluene, 11 parts by weight of trimethoxysilane (Nippon Synthetic Rubber Co., Ltd., Glaska B solution) was added to prepare a titanium oxide-containing coating composition. # 9, # 1
3 to # 16 Each of the samples was applied by a flow coating method, heat-treated at 120 ° C. for 30 minutes, and cured.
A # 21 sample was obtained. With respect to the obtained sample, the adhesion of the coating film and the hydrophilicity of the titanium oxide particles by photoexcitation were evaluated in the same manner as in Example 1. Table 3 shows the results. Table 3 shows that the adhesion of the coating film can be improved without decreasing the degree of hydrophilicity by the discharge treatment.

[0036]

[Table 3]

Embodiment 3 FIG. (Accelerated hydrophilization of coating film by corona discharge treatment) # 20 sample prepared in Example 2 (contact angle with water 97.4)
゜) was subjected to corona discharge treatment under the same conditions as in Example 1, and
22 samples were obtained. The contact angle of the # 22 sample with water was measured and found to be 13.2 °. Next, # 20 sample, # 2
Each of the two samples was irradiated with a BLB fluorescent lamp having an ultraviolet illuminance of 0.6 mW / cm ² , and the time required for conversion to a contact angle with water to 0 ° was compared. As a result, # 20
While it took 48 hours for the sample, the sample was hydrophilized in 15 hours for the # 22 sample, and it was confirmed that the time required for hydrophilization by corona discharge treatment could be shortened.

Embodiment 4 FIG. (Effect of Post-Corona Discharge Treatment on Adhesion of Coating Film) A sample prepared in the same manner as the # 17 sample prepared in Example 2 was subjected to corona discharge treatment under the same conditions as in Example 1 to obtain a # 2 sample.
Three samples were obtained. The adhesion of the coating film was evaluated for the samples # 17 and # 23 in the same manner as in Example 1. as a result,
In # 17 sample, about 5% peeling was observed,
No peeling was observed in the # 23 sample. From this, it was confirmed that even when the corona discharge was performed after the formation of the coating film, the adhesion of the coating film could be improved.

Embodiment 5 FIG. (Effect of Acrylic Substrate and Curing Temperature on Dimensions) A primer paint (a paint made by Toshiba Silicone, PH93 diluted 6 times with a toluene solvent) is sprayed on a 30 × 20 cm square PMMA plate surface # 24. -After coating by a coating method, the coating was dried at room temperature, and the substrate was covered with a primer resin layer. Next, a silicon-based hard coating agent (Toshiba, manufactured by Toshiba Silicone Co., Ltd.) was applied by a flow coating method and dried at 90 ° C. for 3 hours and at 120 ° C. for 30 minutes. Thus, samples # 25 and # 26 were obtained. # 25, # 2
6 The surface of the sample was immersed in a 5% aqueous sodium hydroxide solution for 30 minutes, the sample was tilted, and it was confirmed that the aqueous solution spread on the surface. After that, the sample was washed with water, and the water was wiped off.
Eight samples were obtained. On the other hand, an anatase type titanium oxide sol 56
Parts by weight (Nissan Chemical Co., TA-15) and 33 parts by weight of silica sol (Glaska A solution made by Nippon Synthetic Rubber), diluted with ethanol, and further mixed with 11 parts by weight of trimethoxysilane (Nippon Synthetic Rubber, Glasca) B liquid) to prepare a titanium oxide-containing coating composition. # 27.
Each of the # 28 samples was applied by a flow coating method, the # 27 sample was at 90 ° C. for 3 hours, and the # 28 sample was 120
The composition was cured by heat treatment at 30 ° C. for 30 minutes to obtain # 29 and # 30 samples. The dimensions of the obtained samples # 29 and # 30 and the original acrylic plate # 24 sample were compared. As a result, while the # 30 sample contracted by about 5%, the # 29 sample showed no dimensional change.

Embodiment 6 FIG. (Dark place maintenance property) About # 21 produced in Example 2, it was left in a dark place for 3 weeks, but the contact angle with water on the surface was previously limited to 4 °.

Embodiment 7 FIG. (Pencil Hardness) A pencil scratch test was performed on the # 6 sample of Example 1 in order to more quantitatively examine the wear resistance of the titanium oxide-containing top coat. In the pencil scratch test, the surface of the sample was scratched with a pencil lead according to Japanese Industrial Standard (JIS) H8602, and the hardest pencil lead from which the top coat was peeled was detected. As a result, a favorable result of 4H was obtained.

Embodiment 8 FIG. (Ultraviolet light source) First, a polycarbonate plate of 10 cm square was immersed in primer paint (PC-7A, manufactured by Shin-Etsu Silicone Co., Ltd.).
By the dip coating method of pulling up at mm / min,
After covering the polycarbonate plate with the primer resin layer, 12
After drying at 0 ° C. for 30 minutes, a # 31 sample was obtained. next,#
After immersing the 31 sample in a silicone-based hard coating solution (KP-85, manufactured by Shin-Etsu Silicone), the # 31 sample was hardened by a dip coating method of pulling up at 100 mm / min. And dried at 120 ° C. for 60 minutes to obtain a # 32 sample. On the surface of the # 32 sample, an ultraviolet cleaning and reforming device (PL21-20, manufactured by Sen Engineering)
0, low-pressure mercury lamp 200W, wavelength 253.7 nm and 184.9 nm), the distance between the light source and the sample surface was set to 10 mm, and the sample surface was irradiated with ultraviolet rays for 5 minutes to obtain a # 33 sample. . The sample surface is 85 by UV irradiation
It was hydrophilized from ゜ to 21 ゜. Next, the # 33 sample was treated with a photocatalytic coating solution (solid content was 150 parts by weight of anatase type titanium oxide particles, 37 parts by weight of silica particles, 79 parts by weight of methyltrimethoxysilane, γ-glycoxide propyltrimethoxy). Silane (34 parts by weight)
# 3 by the dip coating method,
After coating the three samples with the photocatalytic coating solution, they were dried at 120 ° C. for 60 minutes to form a surface layer containing the photocatalyst and the silicone, and a # 34 sample was obtained. The # 34 sample was irradiated with ultraviolet light of 0.3 mW / cm ² for 24 hours using a BLB fluorescent lamp to obtain a # 35 sample. Measurement of the contact angle of the # 35 sample surface with water showed 0 ° hydrophilicity. Further, the adhesion of the coating film of the # 35 sample was examined in the same manner as in Example 1. As a result, no peeling occurred. From the above, instead of corona discharge, even when a hydrophilic treatment is performed using a general ultraviolet light source, a surface layer exhibiting superhydrophilicity is firmly fixed to a substrate having a surface made of resin in response to photoexcitation. It was confirmed that it was possible. According to this method, it is possible to cope with substrates of various shapes and to consume less power than corona discharge, which is considered to be significant.

[0043]

According to the method for hydrophilizing the surface of a substrate having a surface made of a resin, the surface is subjected to a discharge treatment or an alkali treatment,
A step of irradiating with ultraviolet light or a step of irradiating light containing photons having energy capable of exciting the photocatalyst while contacting the photocatalyst; a step of coating the surface with a layer containing the photocatalyst and a silicone resin; Irradiating the layer containing the resin resin with light containing photons having energy capable of exciting the photocatalyst, thereby replacing at least a part of the organic groups bonded to the silicon atoms in the silicone resin with hydroxyl groups. By including the above, while maintaining the degree of hydrophilization according to the photoexcitation of the photocatalyst, it becomes possible to have better wear resistance.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yumiko Katsukawa 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Examiner, Totoki Equipment Co., Ltd. Satoshi Morikawa (56) References JP-A-8-267646 ( JP, A) JP-A-8-67835 (JP, A) JP-A-61-83106 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 27/00-27/42 C08J 7/04-7/06

Claims (16)

(57) [Claims] In a method for hydrophilizing a surface of a substrate having a surface made of a resin, a step of hydrophilically treating the surface; a step of coating the surface with a layer containing a photocatalyst and a silicone resin; Substituting at least a part of the organic groups bonded to silicon atoms in the resin with hydroxyl groups. 2. A method for hydrophilizing a surface of a substrate having a surface made of a resin, the step of subjecting the surface to a hydrophilic treatment, the step of coating the surface with a layer containing a photocatalyst and a silicone resin; Substituting at least a part of the organic group bonded to the silicon atom in the resin with a hydroxyl group, and irradiating light containing photons having energy capable of exciting the photocatalyst to form an adsorbed water layer on the surface of the base material And a step of hydrophilizing the surface of the base material. 3. A method for hydrophilizing a surface of a substrate having a surface made of a resin, comprising: a step of subjecting the surface to a hydrophilic treatment; and a step of coating the surface with a layer containing a photocatalyst and amorphous silica. A method for making a substrate surface hydrophilic. 4. A method for hydrophilizing a surface of a substrate having a surface made of a resin, the step of hydrophilizing the surface, the step of coating the surface with a layer containing a photocatalyst and amorphous silica, and the step of exciting the photocatalyst. Irradiating light containing photons having energy capable of being applied to form an adsorbed water layer on the surface of the substrate, and a method for hydrophilizing the surface of the substrate. 5. A method for hydrophilizing a surface of a substrate having a surface made of a resin, wherein said surface is coated with a layer containing a photocatalyst and a silicone resin, and said surface is bonded to silicon atoms in said silicone resin. A method for hydrophilizing the surface of a substrate, comprising: a step of substituting at least a part of an organic group with a hydroxyl group; and a step of performing an ultraviolet treatment after the step of coating. 6. A method for hydrophilizing a surface of a substrate having a surface made of a resin, wherein said surface is coated with a layer containing a photocatalyst and a silicone resin, and said surface is bonded to silicon atoms in said silicone resin. Substituting at least a part of the organic group with a hydroxyl group, and an energy capable of exciting the photocatalyst.
Irradiating light containing photons having a step of forming an adsorbed water layer on the surface of the substrate, and a step of performing an ultraviolet treatment after the step of coating, a method for hydrophilizing the surface of the substrate, the method comprising: . 7. A method for hydrophilizing a surface of a substrate having a surface made of a resin, wherein the step of coating the surface with a layer containing a photocatalyst and amorphous silica, and a step of performing an ultraviolet treatment after the step of coating, A method for hydrophilizing the surface of a substrate, comprising: 8. A method for hydrophilizing a surface of a substrate having a surface made of a resin, comprising the steps of: coating the surface with a layer containing a photocatalyst and amorphous silica; and containing photons having energy capable of exciting the photocatalyst. A method for hydrophilizing the surface of a substrate, comprising: irradiating light to form an adsorbed water layer on the surface of the substrate; and performing a UV treatment after the step of coating. 9. A method for hydrophilizing a surface of a substrate having a surface made of a resin, comprising: a step of coating the surface with a layer containing a photocatalyst and a silicone resin; and a step of performing an ultraviolet treatment after the step of coating. A method for hydrophilizing the surface of a substrate, comprising: 10. A process for the surface hydrophilic treatment is a process of discharge treatment the surface of the substrate surface according to claim 1 which is any one of the processes of the step of alkali treatment Hydrophilization method. 11. step of the surface hydrophilic treatment is the surface energy can excite the photocatalyst while contacting the photocatalyst - any of claims 1 to 4 is a step of irradiating light with photons having 2. The method for hydrophilizing a substrate surface according to item 1 . 12. The step of substituting at least a part of an organic group bonded to a silicon atom in the silicone resin with a hydroxyl group includes the step of causing the layer containing the photocatalyst and the silicone resin to excite the photocatalyst. any of claims 1, 2, 5, and 6 is a step of irradiating light with photons having
2. The method for hydrophilizing a substrate surface according to item 1 . 13. The step of substituting at least a part of an organic group bonded to a silicon atom in the silicone resin with a hydroxyl group is a step of subjecting a surface of the layer containing the photocatalyst and the silicone resin to a corona discharge treatment. Claim 1, characterized in that:
7. The method for hydrophilizing a substrate according to any one of 2, 5, and 6. 14. The step of covering the base material with an acrylic resin, and covering with a layer containing the photocatalyst and a silicone resin,
Mixing an organoalkoxysilane, a hydrolyzate thereof, and a photocatalyst particle with a film-forming element containing at least one of the dehydration-condensation polymer, and a step of applying the mixture;
The method according to any one of claims 1, 2 , 5 , 6 , and 9 to 13 , further comprising a step of heat-curing the film-forming element, and wherein the heat-curing is performed at 90 ° C or lower. A method for hydrophilizing the material surface. 15. The step of coating the base material with an acrylic resin and coating with a layer containing the photocatalyst and amorphous silica includes a coating containing at least one of tetraalkoxysilane, a hydrolyzate thereof, and a dehydration-condensation polymer thereof. A method comprising: mixing a film-forming element and photocatalyst particles; applying the mixture; and heat-curing the film-forming element, wherein the heat-curing is performed at 90 ° C. or lower. 3,
The method for hydrophilizing the surface of a substrate according to any one of 4, 7 to 13. 16. The step of coating at least the surface of the base material with a vinyl chloride resin and coating the layer with the photocatalyst and amorphous silica comprises at least one of tetraalkoxysilane, a hydrolyzate thereof, and a dehydration-condensation polymer thereof. Mixing a seed-containing film-forming element and photocatalyst particles, applying the mixture, and heat-curing the film-forming element, wherein the heat-curing is performed at 60 ° C. or lower. The method for hydrophilizing a substrate surface according to any one of claims 3, 4 , 7 to 13.