Patent Application
20240190759
The present invention relates to a laminate.
Patent Literature 1 discloses a glass article provided with a functional film that contains silica microparticles and titanium oxide microparticles. The glass article is described as having both a photocatalytic function and a reflection suppressing function.
However, there are high demands for the photocatalytic function (antibacterial function) and the reflection suppressing function, and further improvement is desired. The present invention was made to address this issue and has an object of providing a laminate that has both the photocatalytic function and the reflection suppressing function.
Item 1: A laminate including:
Item 2: The laminate according to Item 1,
Item 3: The laminate according to Item 1 or 2,
Item 4: The laminate according to any one of Items 1 to 3,
Item 5: The laminate according to any one of Items 1 to 4,
Item 6: The laminate according to any one of Items 1 to 5,
Item 7: The laminate according to any one of Items 1 to 6,
Item 8: The laminate according to any one of Items 1 to 7,
Item 9: The laminate according to any one of Items 1 to 8,
Item 10: The laminate according to any one of Items 1 to 9,
Item 11: The laminate according to Item 10,
Item 12: The laminate according to any one of Items 1 to 11,
According to the present invention, the photocatalytic function and the reflection suppressing function can be realized at the same time.
Hereinafter, an embodiment in which a laminate according to the present invention is applied to a glass member will be described with reference to the drawings. The glass member according to the present embodiment can be used in various applications. For example, the glass member can be used to cover an article or can be used as a part of a structure. Examples of articles include common displays and various devices such as mobile PCs, tablet PCs, in-vehicle devices such as car navigation systems, devices of which at least a portion has a display function realized by electronic components, and display devices that do not have an electronic display function but display something to the outside. The glass member is applicable to not only devices but also articles to be displayed to the outside, such as commodities. Examples of the structure mentioned above include various structures in which glass is used such as buildings, cases such as show cases, glass plates of copying machines, and partition panels.
The glass plate 1 can be made of general-purpose soda-lime glass, borosilicate glass, aluminosilicate glass, alkali-free glass, or other types of glass, for example. Also, the glass plate 1 can be formed using a float process. The float process makes it possible to obtain a glass plate 1 having a flat and smooth surface. However, the glass plate 10 may have recesses and protrusions on its main surface, and may be made of figured glass, for example. Figured glass can be formed using a process called a roll out process. Figured glass that is formed using this production process usually has periodic recesses and protrusions in one direction that extends along the main surface of the glass plate.
In the float process, molten glass is continuously supplied onto a molten metal such as molten tin, and the supplied molten glass is made to flow over the molten metal and thereby formed into a strip-like shape. The thus formed glass is called a “glass ribbon”.
The glass ribbon is cooled as it moves downstream, and the cooled and solidified glass ribbon is raised from the molten metal by rollers. Then, the glass ribbon is transported to an annealing lehr by rollers, annealed, and then cut. A float glass plate can be obtained in this manner.
Although the thickness of the glass plate 1 is not particularly limited, a thin glass plate is better for weight reduction. The thickness of the glass plate 1 is preferably 0.3 to 5 mm, and more preferably 0.6 to 2.5 mm, for example. The reason for this is that, if the glass plate 10 is excessively thin, the strength is reduced, while if the glass plate 10 is excessively thick, the article 100 may be distorted when seen through the glass member 10.
The glass plate 1 typically may be a flat plate, but may also be a bent plate. In particular, in the case where a member to be protected has a non-flat surface such as a curved surface, the glass plate 1 preferably has a main surface with a non-flat surface shape that fits the non-flat surface of the member to be protected. In this case, the entire glass plate 1 may be bent so as to have a constant curvature, or the glass plate 1 may be locally bent. The main surface of the glass plate 1 may be constituted by, for example, a plurality of flat surfaces connected via a curved surface. The radius of curvature of the glass plate 1 can be 5,000 mm or less, for example. The lower limit value of this radius of curvature can be 10 mm or more, for example, but a locally bent portion, in particular, may have an even smaller radius of curvature, which can be 1 mm or more, for example.
A glass plate having the following composition can also be used. Hereinafter, unless otherwise specified, “%” as used when indicating the amounts of components of the glass plate 1 means “mol %” in all instances. Also, in this specification, the wording “substantially composed of” means that the total content of listed components accounts for 99.5 mass or more, preferably 99.9 mass or more, and more preferably 99.95 mass % or more. The wording “substantially does not contain” means that the content of the component in question is 0.1 mass % or less, and preferably 0.05 mass %, or less.
Based on the composition (hereinafter also referred to as “SL in the narrow sense”, or simply as “SL”) of float plate glass, which is widely used as a composition of glass that is suitable for producing a glass plate using the float process, the inventor of the present invention has conducted a study to find a composition with which chemical strengthening properties of the SL in the narrow sense can be improved, while enabling T2, T4, and other characteristics to approximate as closely as possible to those of the SL in the narrow sense, within a composition range that is considered by a person skilled in the art to be soda lime silicate glass (hereinafter also referred to as “SL in the broad sense”) that is suitable for the float process, or more specifically, within the following mass' range:
Hereinafter, components included in the glass composition of the glass plate 1 will be described.
SiO2 is a main component constituting the glass plate 1. An excessively low SiO2 content results in a decrease in chemical durability, such as water resistance, and heat resistance of glass. On the other hand, an excessively high SiO2 content results in an increase in the viscosity of the glass plate 1 at high temperatures, making it difficult to melt and form the glass plate 1. Therefore, an appropriate range of the SiO2 content is 66 to 72 mol %, and preferably 67 to 70 mol %.
(Al2O3)
Al2O3 is a component for improving the chemical durability, such as water resistance, of the glass plate 1 and furthermore facilitating the movement of alkali metal ions in the glass, thereby increasing the surface compressive stress after chemical strengthening and increasing the depth of the stress layer. On the other hand, an excessively high Al2O3 content results in an increase in the viscosity of the glass melt, thereby increasing T2 and T4 and degrading the clarity of the glass melt, and consequently, making it difficult to produce a high-quality glass plate.
Therefore, an appropriate range of the Al2O3 content is 1 to 12 mol %. The Al2O3 content is preferably 10 mol % or less and preferably 2 mol % or more.
MgO is an essential component that improves the meltability of glass. In order to sufficiently achieve this effect, it is preferable that MgO is added to this glass plate 1. Furthermore, if the MgO content is less than 8 mol %, the surface compressive stress after chemical strengthening decreases, and the depth of the stress layer thus is likely to be small. On the other hand, if the MgO content is increased to more than a suitable amount, strengthening performance that is obtained through chemical strengthening degrades; in particular, the depth of the surface compressive stress layer drastically decreases. Although this adverse effect of MgO is the smallest compared with those of all the other alkaline earth metal oxides, the MgO content in this glass plate 1 is 15 mol or less. Furthermore, a high MgO content increases T2 and T4 and degrades the clarity of the glass melt, thereby making it difficult to produce a high-quality glass plate.
Therefore, the MgO content in this glass plate 1 is within a range of 1 to 15 mol %, and preferably 8 mol % or more and 12 mol % or less.
CaO has the effect of reducing the viscosity at high temperatures; however, an extremely high CaO content that exceeds a suitable range is likely to devitrify the glass plate 1 and inhibits the movement of sodium ions in the glass plate 1. In the case where CaO is not contained, the surface compressive stress after chemical strengthening is likely to decrease. On the other hand, if CaO is contained in an amount of more than 8 mol %, the surface compressive stress after chemical strengthening markedly decreases, the depth of the compressive stress layer markedly decreases, and the glass plate 1 is likely to be devitrified.
Therefore, an appropriate range of the CaO content is 1 to 8 mol %. The CaO content is preferably 7 mol % or less and preferably 3 mole or more.
SrO and BaO significantly reduce the viscosity of the glass plate 1, and when contained in a small amount, SrO and BaO more markedly have the effect of reducing the liquid phase temperature TL than CaO. However, even when added in a very small amount, SrO and BaO markedly hinder the movement of sodium ions in the glass plate 1, significantly reduce the surface compressive stress, and considerably reduce the depth of the compressive stress layer.
Therefore, it is preferable that this glass plate 1 substantially does not contain SrO and BaO.
Na2O is a component for increasing the surface compressive stress and increasing the depth of the surface compressive stress layer, due to sodium ions being replaced by potassium ions. However, if the Na2O content is increased to more than a suitable amount, stress relaxation during chemical strengthening treatment surpasses generation of the surface compressive stress due to ion exchange during chemical strengthening treatment, and as a result, the surface compressive stress is likely to decrease.
Also, while Na2O is a component for improving meltability and reducing T4 and T2, an excessively high Na2O content results in a significant decrease in water resistance of the glass. If the Na2O content in the glass plate 1 is 10 mol % or more, a sufficient effect of reducing T4 and T2 can be obtained, and if the Na2O content is more than 16 mol %, the surface compressive stress markedly decreases due to the stress relaxation.
Therefore, an appropriate range of the Na2O content in the glass plate 1 of the present embodiment is 10 to 16 mol %. The Na2O content is preferably 12 mol % or more, and more preferably 15 mol % or less.
K2O, like Na2O, is a component that improves the meltability of glass. Also, in a low K2O content range, the ion exchange rate during chemical strengthening increases, and the depth of the surface compressive stress layer thus increases, while, on the other hand, the liquid phase temperature TL of the glass plate 1 decreases. Therefore, it is preferable that K2O is contained in a small amount.
On the other hand, although the effect of reducing T4 and T2 of K2O is smaller than that of Na2O, a high K2O content inhibits clarification of the glass melt. Furthermore, the higher the K2O content, the lower the surface compressive stress after the chemical strengthening. Therefore, an appropriate range of the K2O content is 0 to 1 mol %.
Li2O, when contained even in a small amount, significantly reduces the depth of the compressive stress layer. Also, in the case where a glass member containing Li2O is chemically strengthened in a molten salt of potassium nitrate alone, the molten salt deteriorates significantly faster than in the case of a glass member that does not contain Li2O. Specifically, in the case where the glass members are repeatedly chemically strengthened using the same molten salt, surface compressive stress generated in the glass surface of the glass member containing Li2O decreases in the fewer cycles. Therefore, although the glass plate 1 of the present embodiment may contain Li2O in an amount of 1 mol % or less, it is preferred that the glass plate 1 substantially does not contain Li2O.
(B2O3)
B2O3 is a component that lowers the viscosity of the glass plate 1 and improves meltability. However, if the B2O3 content is excessively high, phase separation is likely to occur in the glass plate 1, resulting in a decrease in the water resistance of the glass plate 1. Also, a compound formed of B2O3 and an alkali metal oxide may volatilize and cause damage to a refractory material of a glass melting chamber. Furthermore, if B2O3 is contained, the depth of the compressive stress layer formed by chemical strengthening becomes smaller. Therefore, an appropriate B2O3 content is 0.5 mol % or less. In the present invention, it is more preferable that the glass plate 1 substantially does not contain B2O3.
(Fe2O3)
Usually, Fe is present as Fe2+ or Fe3+ in glass, and functions as a colorant. Fe3+ is a component that improves the ultraviolet absorption performance of glass, and Fe2+ is a component that improves heat absorption performance. In the case where the glass plate 1 is to be used as a cover glass for a display, its coloration is required to be inconspicuous, and therefore, a lower Fe content is preferred. However, Fe from industrial raw materials is often inevitably mixed in glass. Therefore, the content of iron oxide in terms of Fe2O3 is preferably 0.15 mass % or less, more preferably 0.1 mass % or less, and even more preferably 0.02 mass % or less, where the glass plate 1 as a whole is taken as 100 mass %.
TiO2 is a component that reduces the viscosity of the glass plate 1 and also increases the surface compressive stress generated by chemical strengthening, but TiO2 may add a yellow color to the glass plate 1. Therefore, an appropriate TiO2 content is 0 to 0.2 mass %. Furthermore, TiO2 from commonly used industrial raw materials is inevitably mixed in the glass plate 1 and thus may be contained therein in an amount of approximately 0.05 mass %. With a content like this, TiO2 does not add any color to glass and may be contained in the glass plate 1 of the present embodiment.
Especially when producing a glass plate using the float process, ZrO2 may be mixed in the glass plate 1 from refractory bricks constituting a glass melting furnace, and the ZrO2 content in that case is known to be approximately 0.01 mass %. On the other hand, ZrO2 is a component that improves the water resistance of glass and increases the surface compressive stress generated by chemical strengthening. However, a high ZrO2 content may cause an increase in working temperature T4 and a sharp increase in liquid phase temperature TL and, in the production of a glass plate using the float process, makes it likely that crystals containing precipitated Zr remain in the produced glass as foreign matter. Therefore, an appropriate ZrO2 content is 0 to 0.1 mass %.
In the float process, a sulfate such as sodium sulfate (Na2SO4) is widely used as a clarifying agent. The sulfate decomposes in the molten glass and generates a gas component, and thus, degassing of the glass melt is promoted, but a portion of the gas component dissolves and remains in the glass plate 1 as SO3. It is preferable that the SO3 content in the glass plate 1 of the present invention is 0 to 0.3 mass %.
CeO2 is used as a clarifying agent. CeO2 produces O2 gas in the molten glass, and therefore, CeO2 contributes to degassing. On the other hand, an excessively high CeO2 content causes the glass to be discolored to yellow. Therefore, the CeO2 content is preferably 0 to 0.5 mass %, more preferably 0 to 0.3 mass %, and even more preferably 0 to 0.1 mass %.
It is known that, in a glass plate that is formed using the float process, tin from a tin bath has diffused into a surface that has been in contact with the tin bath during the formation of the glass plate, and the diffused tin is present as SnO2. Also, SnO2 mixed with glass raw materials contributes to degassing. The SnO2 content in the glass plate 1 of the present invention is preferably 0 to 0.3 masse.
It is preferable that the glass plate 1 according to the present embodiment is substantially composed of the above-listed components. However, the glass plate 1 according to the present embodiment may also contain components other than the above-listed components as long as the content of each such component is preferably less than 0.1 masse.
Examples of the components that can be contained include As2O5, Sb2O5, Cl, and F that may be added for the purpose of degassing the molten glass in addition to SO3 and SnO2 described above. However, it is preferable that As2O5, Sb2O5, Cl, and F are not added because of their significant adverse effects on the environment and for other reasons. Other examples of the components that can be contained are ZnO, P2O5, GeO2, Ga2O3, Y2O3, and La2O3. Components other than the above that are derived from industrially used raw materials can also be contained as long as the content of each such component does not exceed 0.1 mass %. Since these components may be appropriately added as necessary, or inevitably mixed in, it is possible that the glass plate 1 of the present embodiment substantially does not contain these components.
With the above-described composition, the density of the glass plate 1 according to the present embodiment can be reduced to 2.53 g·cm−3 or less, or 2.51 g·cm−3 or less, or even to 2.50 g·cm−3 or less in certain cases.
In the float process or the like, if there is a significant difference in density between product types of glass, the molten glass having the higher density may stagnate in a bottom portion of the melting furnace when changing the product type of glass that is produced, and therefore, the product type cannot be changed smoothly. The density of soda-lime glass that is currently mass-produced using the float process is approximately 2.50 g·cm−3. For this reason, in the context of mass production using the float process, it is preferable that the density of the glass plate 1 is close to the aforementioned values, or specifically is 2.45 to 2.55 g·cm−3, more preferably 2.47 to 2.53 g·cm−3, and even more preferably 2.47 to 2.50 g·cm−3.
A glass substrate may be warped when subjected to chemical strengthening that involves ion exchange. In order to prevent the warpage, it is preferable that the glass plate 1 has a high elasticity. According to the present invention, the elasticity (Young's modulus: E) of the glass plate 1 can be increased to 70 GPa or more, or even to 72 GPa or more.
Hereinafter, chemical strengthening of the glass plate 1 will be described.
The glass plate 1 according to the present invention can be chemically strengthened by performing an ion exchange treatment in which the glass plate 1 that contains sodium is brought into contact with a molten salt that contains monovalent cations, preferably potassium ions, that have a larger ionic radius than sodium ions, and sodium ions in the glass plate 1 are replaced with the monovalent cations. A compressive stress layer in which compressive stress is applied is thus formed in the surface of the glass plate 1.
A typical example of the molten salt is potassium nitrate. Although a mixed molten salt of potassium nitrate and sodium nitrate may be used, a molten salt of potassium nitrate alone is preferable because it is difficult to control the concentration of the mixed molten salt.
The surface compressive stress and the depth of the compressive stress layer of a tempered glass member can be controlled by adjusting not only the glass composition of the article but also the temperature of the molten salt during the ion exchange treatment and the treatment time.
A tempered glass member with an extremely high surface compressive stress and an extremely deep depth of the compressive stress layer can be obtained by bringing the above-described glass plate 1 into contact with a potassium nitrate molten salt. Specifically, it is possible to obtain a tempered glass member having a surface compressive stress of 700 MPa or more and a compressive stress layer with a depth of 20 μm or more. Furthermore, it is also possible to obtain a tempered glass member having a compressive stress layer with a depth of 20 μm or more and a surface compressive stress of 750 MPa or more.
In a case where a glass plate 1 having a thickness of 3 mm or more is used, air-quench tempering can be used as a common tempering method, rather than chemical strengthening.
Next, the functional film 2 will be described with reference to
The inorganic oxide serves as a binder that retains inorganic oxide microparticles and metal ions. For example, the functional film contains a silicon oxide, which is an oxide of Si, as the inorganic oxide, and preferably contains a silicon oxide as a main component. Containing a silicon oxide as the main component is suitable for reducing the refractive index of the film and suppressing the reflectance of the film. The functional film may contain a component other than a silicon oxide, and may contain a component that partially contains a silicon oxide.
The component that partially contains a silicon oxide may be, for example, a component in which a silicon atom and an oxygen atom are alternately bonded forming a three-dimensional network structure of three-dimensionally spreading siloxane bonds (Si—O—Si). In this portion of the component, an atom other than a silicon atom and an oxygen atom, a functional group, or the like is bonded to the silicon atom or oxygen atom. Examples of the atom other than a silicon atom and an oxygen atom include a nitrogen atom, a carbon atom, a hydrogen atom, and metal elements that will be described in the next paragraph. Examples of the functional group include organic groups that will be described as R in a paragraph below. This component is not a silicon oxide in a strict sense because it is not composed only of a silicon atom and an oxygen atom. However, in describing the characteristics of the functional film 2, treating a silicon oxide portion that is composed of a silicon atom and an oxygen atom as a “silicon oxide” is appropriate and is also consistent with usage in the field. In this specification, the silicon oxide portion is also treated as a silicon oxide. As is clear from the above description, the atomic ratio between silicon atoms and oxygen atoms in a silicon oxide need not be stoichiometric (1:2).
The functional film 2 can contain a metal oxide other than a silicon oxide, or specifically, a metal oxide component or a metal oxide portion that contains an element other than silicon. The metal oxide that can be contained in the functional film 2 is not particularly limited, and may be an oxide of at least one metal element selected from the group consisting of Al, Ti, Zr, Ta, Nb, Nd, La, Ce, and Sn, for example. The functional film 2 may contain an inorganic compound component other than an oxide, examples of which include a nitride, a carbide, and a halide, and may contain an organic compound component.
A metal oxide such as a silicon oxide can be formed from a hydrolyzable organic metal compound. An example of a hydrolyzable silicon compound is a compound represented by Formula (1):
RnSiY4-n (1)
R is preferably an alkyl group, for example, an alkyl group having 1 to 3 carbon atoms, and a methyl group is particularly preferable. Y is preferably an alkoxy group, for example, an alkoxy group having 1 to 4 carbon atoms, and a methoxy group and an ethoxy group are particularly preferable. Two or more compounds represented by the formula above may also be used in combination. As an example of this combination, tetraalkoxysilane, where n is 0, and monoalkyltrialkoxysilane, where n is 1, may be used together.
A specific example of a preferable silicon compound having a hydrolyzable group and represented by Formula (I) is a silicon alkoxide where X in formula (I) is an alkoxyl group. More preferably, the silicon alkoxide includes a four-functional silicon alkoxide that corresponds to a compound (SiX4) where m=0 in Formula (I). Specific examples of four-functional silicon alkoxides include tetramethoxysilane and tetraethoxysilane. A silicon alkoxide may be used alone, or two or more silicon alkoxides may be used in combination. When two or more silicon alkoxides are used in combination, it is more preferable that a four-functional silicon alkoxide is the main component of silicon alkoxides.
A compound represented by Formula (1) after hydrolysis and polycondensation forms a network structure in which silicon atoms are bonded to one another via oxygen atoms. In this structure, the organic groups represented by R are contained in a state of being directly bonded to silicon atoms.
The content of the inorganic oxide in the functional film 2 is preferably 5 to 50 mass %, and more preferably 10 to 40 mass %. A large content of the inorganic oxide deteriorates an anti-reflection function as described later and thus is not preferable. On the other hand, when the content of the inorganic oxide is small, bonding areas between microparticles and with the glass plate 1 become small and wear resistance is deteriorated.
The functional film 2 further contains inorganic oxide microparticles as at least a portion of the inorganic oxide. As shown in
If the average particle diameter of inorganic oxide microparticles is too large, the functional film 2 may be opaque, and if the average particle diameter is too small, the inorganic oxide microparticles aggregate and are difficult to disperse uniformly. From this standpoint, the average particle diameter of primary particles of the inorganic oxide microparticles is preferably 50 to 150 nm, for example, and more preferably 80 to 130 nm. Also, the average particle diameter of the inorganic oxide microparticles is preferably greater than the thickness of the functional film 2. Also, the average particle diameter of the inorganic oxide microparticles is preferably at least five times the average particle diameter of photocatalyst microparticles, which will be described later. When the average particle diameter of photocatalyst particles is small as described above, the influence of an apparent refractive index is small and reflection can be suppressed.
Note that the average particle diameter of inorganic oxide microparticles referred to here is the average particle diameter of primary particles of the inorganic oxide microparticles. The same also applies to photocatalyst microparticles, which will be described later. The average particle diameter of inorganic oxide microparticles is determined by measuring particle diameters of randomly selected 50 microparticles observed using a scanning electron microscope and calculating an average value of the measured values. When the content of inorganic oxide microparticles is large, the functional film 2 may be opaque. The content of inorganic oxide microparticles in the functional film 2 is preferably 10 to 50 mass %, and more preferably 15 to 45 mass %.
The ratio of the content of inorganic oxide microparticles to the total content of inorganic oxide microparticles and the inorganic oxide (binder) in the functional film 2 is preferably greater than 0.4. That is, it is preferable that the content of the binder is small as described above in terms of the relationship between inorganic oxide microparticles and the binder as well.
As described above, inorganic oxide microparticles are dispersed over the glass plate, and the distance between adjacent inorganic oxide microparticles is preferably 1 μm or less. This is because when the distance is too large, widths of recesses and protrusions formed in the surface of the functional film become large, and it becomes difficult to reduce the apparent refractive index.
As shown in
The refractive index of the photocatalyst microparticles can be 2.0 to 2.8, for example. The refractive index may be larger than the refractive index of the glass plate 1, which is a substrate.
Metal ions have an antibacterial property, and can be formed of monovalent or divalent copper ions, silver ions, or the like. The content of metal ions in the functional film 2 is preferably 1 to 30 mass % of the functional film 2, for example, and more preferably 3 to 15 mass %.
The thickness of the functional film 2 is preferably 10 to 200 nm, for example, and more preferably 50 to 150 nm. If the thickness is too large, the haze ratio may become high or the film may be colored excessively. On the other hand, if the thickness is too small, the functional film 2 may not be able to retain inorganic oxide microparticles and metal ions and the inorganic oxide microparticles and metal ions may separate from the functional film 2. Also, durability of the functional film may become low.
The refractive index of the functional film 2 is preferably 1.1 to 1.5, and more preferably 1.2 to 1.4. As described above, in the functional film 2 according to the present invention, photocatalyst microparticles are stacked between dispersed inorganic oxide microparticles, and the apparent refractive index of the functional film 2 can be reduced by voids formed by the stacked photocatalyst microparticles. As a result, the reflectance can be reduced. The refractive index can be measured using a method specified in JIS B-7071-1:2015, for example.
The reflectance of the functional film 2 is preferably 0 to 10, and more preferably 2 to 7. The reflectance can be measured based on JIS R-3106:2019, for example.
There is no particular limitation on the method for forming the functional film 2, and the functional film 2 can be formed in the following manner, for example. First, a material that forms the above-described three-dimensional network structure, for example, a silicon alkoxide such as tetraethoxysilane is dissolved to obtain a solution under an acidic condition, and thus, a precursor solution is produced. Then, a liquid that contains the above-described antibacterial metal ions, for example, a copper chloride aqueous solution, a dispersion that contains inorganic oxide microparticles such as colloidal silica, and a dispersion that contains photocatalyst microparticles such as titanium oxide microparticles are mixed with the precursor to produce a coating liquid for forming the functional film.
The coating liquid may be irradiated with ultraviolet rays to activate photocatalyst microparticles. In this case, the coating liquid can be irradiated with ultraviolet rays with an amount of 5 to 50 W/m2 for 1 to 24 hours, for example.
Next, the coating liquid is applied to the first surface of the cleaned glass plate 1. Although there is no particular limitation on the application method, flow coating, spray coating, spin coating, or the like can be used, for example. After that, the applied coating liquid is dried at a predetermined temperature (e.g., 80° C. to 200° C.) in an oven or the like in order to, for example, volatilize an alcohol from the solution, and then sintered at a predetermined temperature (e.g., 200° C. to 500° C.) for the purpose of hydrolysis and organic chain decomposition, for example. Thus, the functional film 2 can be obtained.
As described above, substantially a single layer of inorganic oxide microparticles is formed in the completed functional film. This configuration can be achieved by applying the coating liquid thin or setting the solid content concentration in the coating liquid to 10% or less, for example, preferably 7% or less, and more preferably 5% or less.
With regard to the optical properties of the glass member 10, for example, visible light transmittance is preferably 80% or more, and more preferably 90% or more. Furthermore, the haze ratio of the glass member 10 is 20% or less, 15% or less, or particularly 10% or less, for example, or may optionally be 0.1% to 8.0% or even 0.1% to 6.0%.
Although an embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. Note that the following variations can be combined as appropriate.
In the above embodiment, a glass plate is used as the substrate of the present invention, but a resin substrate can also be used as well as a glass plate.
Hereinafter, examples of the present invention will be described. However, the present invention is not limited to the following examples.
Float glass plates each having a size of 50 mm×50 mm and a thickness of 1.1 mm were prepared, and alkaline ultrasonic cleaning was performed on the surfaces of the glass plates. Next, functional-film-forming coating liquids having the following compositions were prepared for Examples 1 to 12. Solid content concentrations in the coating liquids of Examples 1 to 5 were 5%, solid content concentrations in the coating liquids of Examples 6 to 11 were 7%, and solid content concentrations in the coating liquids of Examples 12 to 14 were 4%. Copper ions were contained only in Example 14. Details of “Concentrate Total” in Tables 1 to 3 are shown in Table 4. The unit of all values is gram.
“STS-01” in Tables 1 to 3 represents a TiO2 microparticle dispersion manufactured by ISHIHARA SANGYO KAISHA, LTD., and “PL-7” in Table 4 represents a SiO2 microparticle dispersion manufactured by FUSO CHEMICAL CO., LTD.
Subsequently, the coating liquids according to Examples 1 to 14 were applied to the surfaces of the glass plates through spin coating, and then the glass plates were heated at 300° C. for 30 minutes in an oven. Thus, glass members according to Examples 1 to 15 were obtained. The thickness of a functional film in each example was about 100 nm.
Compositions of the functional films in the completed glass members were as follows. The unit of the values is mass %. As shown in Tables given below, the content of TiO2 microparticles was mainly changed between Examples 1 to 5. On the other hand, in Examples 6 to 11, the content of TiO2 microparticles was constant and contents of SiO2 microparticles and a SiO2 binder were changed.
The following tests were performed on the glass members of Examples 1 to 14.
The reflectance was measured based on JIS R-3106:2019. A glass plate on which a functional film was not formed was used for comparison. Results are shown in
As shown in
In both wavelength ranges, the reflectance was reduced when compared with the glass plate that was not provided with an antibacterial film. On the other hand, as shown in
As shown in
The glass members of Examples 1 to 10 were left to stand while leaning against a support in a high-temperature high-humidity environment (85° C., 85% RH) for 48 hours. Thereafter, the glass members were irradiated with UV rays with an amount of 1 mW/cm2 using a black light, and the time it took until the contact angle of a water droplet dripped onto the glass members became 5° or less was measured. Results were as follows.
As shown in Example 1 to 5, the larger the content of TiO2 microparticles was, the shorter the recovery time was, but conversely, the recovery time became shorter when the content of TiO2 microparticles exceeded 50 masse. This is presumably because when the content of TiO2 microparticles is too large, the number of TiO2 microparticles adhering to SiO2 microparticles decreases and consequently the surface area of TiO2 microparticles decreases.
Antibacterial properties were evaluated under the following conditions based on JIS R1702:2020 (film cover method).
The antibacterial activity value of Example 14 containing copper ions, which are antibacterial metal ions, was 4.0 or more. Antibacterial activity values of Examples 1 to 13 were 3.5 or more. Because a specimen with an antibacterial activity value of 2.0 or more is evaluated to have antibacterial activity, sufficient antibacterial performance was confirmed in the glass members according to these examples.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-062306 | Mar 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/011432 | 3/14/2022 | WO |
