JP2015040384A - White glass for interior finishing of adit or tunnel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for interior finishing of an adit or a tunnel, which can maintain washing performance, reflection performance and strength, even when a scratch or a chip is made on a surface.SOLUTION: White glass for interior finishing of an adit or a tunnel has a thickness of 0.5 mm or more.

Description

  The present invention relates to white glass for interiors of tunnels or tunnels.

  Tunnels or tunnels have high temperature and humidity, and air is contaminated, so the wall surface deteriorates quickly. In addition, because the daylight is not exposed to the tunnels or tunnels, lighting is necessary not only at night but also in the daytime. However, the power consumed by the tunnels and tunnels throughout the country is enormous, and energy saving is urgent. ing.

  Traditionally, tiles with high reflectivity have been used as interior materials for tunnels or tunnels. By using tiles with high reflectivity, the number of lighting fixtures can be reduced and energy has been saved. In addition, visibility can be improved. In the tunnel interior tiles used so far, a glaze has been applied on the ceramic substrate for the purpose of improving the cleanability, reflectivity or strength.

  For example, Patent Document 1 describes a light reflecting tile for tunnel interior in which glaze is applied for the purpose of increasing the strength on the surface side having a plurality of granular irregularities formed on the surface of a tile base material. Moreover, the glaze which added the zirconia to the transparent glaze and made it cloudy as white glaze is described.

  Further, Patent Document 2 describes a highly reflective white tile used as a building material or wall material of a building, and describes that antifouling treatment is performed with a glaze as necessary.

JP 2010-255188 A JP 2011-226156 A

  However, if the tunnel or tunnel is decorated with tiles, even if glaze is applied to the surface, the cleaning performance, reflection performance, or strength may be reduced due to scratches or chips on the tile surface caused by handling during construction. It was. In addition, there is a concern that the glaze easily peels due to the difference in thermal expansion between the glaze and the ceramic substrate.

  Accordingly, an object of the present invention is to provide a mine or tunnel interior material that can maintain cleaning performance, reflection performance, and strength even when surface scratches or chips occur.

  The present inventors have found that by using white glass having a thickness of 0.5 mm or more for interiors of tunnels or tunnels, it is possible to maintain cleaning performance, reflection performance and strength even if surface scratches or nicks occur. The present invention has been completed.

That is, the present invention is as follows.
1. White glass for interiors of tunnels or tunnels with a thickness of 0.5 mm or more.
2. 2. White glass for interior of a tunnel or tunnel according to item 1 above, wherein the total light reflectance R ₆₀₀ of light having a wavelength of 600 nm is 50% or more.
3. 3. White glass for interior of a tunnel or tunnel according to item 1 or 2, which is a white phase-separated glass.
4). 4. The white glass for interior of a mine tunnel or a tunnel according to item 3, wherein the white phase-separated glass is white binodal phase-separated glass.
5. 5. White glass for interior of a tunnel or tunnel according to any one of the preceding items 1 to 4, which contains 0 to 25% of Al ₂ O ₃ in terms of a molar percentage based on the following oxide.
6). 6. White glass for interior of a tunnel or tunnel according to any one of items 1 to 5, wherein the density is 3.0 g / cm ³ or less.
7). The white glass for interior of a mine tunnel or a tunnel according to any one of items 1 to 6, which does not contain filler mixed glass.
8). 8. White glass for interior of a tunnel or tunnel according to any one of items 1 to 7, wherein the thickness is 30 mm or less.
9. 9. White glass for interior of a tunnel or tunnel according to any one of the preceding items 1 to 8, wherein the acid resistance (0.1 M HCl treatment at 90 ° C. for 20 hours) is 2 mg / cm ² or less.
10. 10. White glass for interior of a mine or tunnel according to any one of items 1 to 9, wherein the bending strength is 60 MPa or more.

  When tiles are used for interiors of tunnels or tunnels, if the glaze phase on the surface of the tiles is chipped and peeled off, the ceramic substrate will be exposed, and will be easily soiled and difficult to fall off. In contrast, according to the present invention, white glass is used for interiors of tunnels or tunnels, so that even if scratches or chips on the glass surface occur, the new surface is glass, so that it is difficult to get dirt and cleaning performance. In addition, the reflection performance can be maintained.

  In addition, the white glass used in the present invention is superior in strength compared to the tile with a glaze applied to the ceramic substrate, and the glass surface is less likely to be scratched or chipped, even if the glass surface is scratched or chipped. Since the new surface is glass, the strength can be maintained.

  Furthermore, according to this invention, it becomes possible to make it the interior material provided with the designability by using the white glass excellent in workability as an interior material of a tunnel or a tunnel.

  Hereinafter, a preferred embodiment of the white glass for interior of a tunnel or tunnel of the present invention will be described.

  In the present specification, “anti-road” refers to a passage formed in the basement mainly used for mining in a mine or the like. A “tunnel” is a man-made or naturally-formed civil engineering structure that passes from the ground to the destination underground, under the sea, or in the mountains, and in the axial direction compared to the height or width of the cross section. An elongated space.

  Artificial tunnels include, for example, roads or railways (railways) constructed for the purpose of laying lifelines such as water or electric wires (for example, common grooves), mining minerals or storing or transporting materials (for example, , Mountain tunnel).

  The thickness of the white glass for interior of the tunnel or tunnel of the present invention (hereinafter also referred to as the white glass of the present invention) is 0.5 mm or more, preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm. That's it. If the thickness is less than 0.5 mm, the strength decreases. Moreover, from a viewpoint of weight reduction, it is preferable that it is 30 mm or less, More preferably, it is 20 mm or less, More preferably, it is 15 mm or less, Most preferably, it is 10 mm or less.

The white glass of the present invention has a total light reflectance R ₆₀₀ of light having a wavelength of 600 nm of preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, and particularly preferably 80% or more. The R ₆₀₀ by 50% or more, it is possible to improve energy saving and visibility. The total light reflectance is measured by the method described later in the examples. Further, the minimum value ( _Rmin ) of the total light reflectance in the wavelength range of 400 to 800 nm is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, and particularly preferably 80% or more. It is.

  The white glass of the present invention can be directly attached to the wall surface with an adhesive or the like. In addition, a white glass panel in which a plurality of white glasses are attached to a cement plate or a metal plate can be installed on the wall surface. Moreover, you may fix with jigs, such as metal and ceramics, instead of sticking directly to a wall surface. Moreover, when fixing with a jig, you may hold | maintain at the edge of glass and you may fix using the hole opened in the white glass surface.

  The white glass of the present invention may be laminated with a resin or the like in order to prevent it from being broken and scattered when a vehicle or the like collides, or a laminated glass using a resin or the like in an intermediate layer between glass and glass. In this case, the glass on the back surface may be white glass or transparent glass.

  In order to make the white glass of the present invention easy to handle or to prevent strength reduction due to cracks or the like, the edge may be polished.

  The white glass of the present invention preferably has a short side or short diameter of 30 mm or more, more preferably 40 mm or more, still more preferably 100 mm or more, and particularly preferably 500 mm or more. By setting it to 30 mm or more, it is possible to prevent an increase in the number of sheets to be installed and improve work efficiency. Further, the length of the long side or the long diameter is preferably 3000 mm or less, more preferably 2000 mm or less, and still more preferably 1000 mm or less. By setting it to 3000 mm or less, it can be easily handled.

  Examples of the white glass of the present invention include white phase-separated glass and white crystallized glass.

  White phase-separated glass is a state in which two or more glass phases coexist inside the glass and has a fine phase-separated structure. The phase-separated structure in white phase-separated glass diffuses light at its interface. The appearance is white due to reflection and scattering.

  White crystallized glass is glass in which fine crystals are precipitated in the glass, and the appearance is white by diffusely reflecting and scattering light at the interface between the glass phase and the crystal phase precipitated in the glass.

  The white glass of the present invention uses light scattering by the fine structure inside the glass to diffuse light over a wide range to create a soft light quality and to have design properties.

  Next, the composition of the white glass used in the present invention will be described. In the present specification, the content of the glass component will be described using a molar percentage display unless otherwise specified.

In the present invention, the content of SiO ₂ is preferably 45 to 75%. SiO ₂ is a basic component that forms a network structure of white glass. By setting it to 45% or more, it exhibits excellent mechanical strength and weather resistance (acid resistance and alkali resistance) (the same applies hereinafter). More preferably, it is 50% or more, more preferably 55% or more, and particularly preferably 57% or more. On the other hand, it can prevent that the melting temperature of glass becomes high by setting it as 75% or less. More preferably, it is 70% or less, More preferably, it is 65% or less.

The total amount of alkali components (Li ₂ O, Na ₂ O, K ₂ O) is preferably 0 to 25%. An alkali component is a component which improves the solubility of glass, and when it contains, it is preferable that it is 1% or more. By containing 1% or more, a sufficient content effect can be obtained. Preferably it is 3% or more, More preferably, it is 5% or more, More preferably, it is 6% or more, Most preferably, it is 8% or more. Moreover, it can prevent that the weather resistance of glass falls by setting it as 25% or less. More preferably, it is 20% or less, More preferably, it is 15% or less.

  The total amount of alkaline earth components (MgO, CaO, SrO, BaO) is preferably 0 to 25%. The alkaline earth component is a component that improves the solubility of the glass, and when it is contained, it is 1% or more. By containing 1% or more, a sufficient content effect can be obtained. Preferably it is 3% or more, More preferably, it is 5% or more, More preferably, it is 6% or more, Most preferably, it is 8% or more. Moreover, it can prevent that the weather resistance of glass falls by setting it as 25% or less. More preferably, it is 20% or less, More preferably, it is 15% or less.

It is preferable to contain 0 to 25% of Al ₂ O ₃ . Al ₂ O ₃ has an effect of improving the stability of the glass or improving the strength. When it is contained, it is preferably contained at 1% or more. By containing 1% or more, a sufficient effect can be obtained. More preferably, it is 2% or more, and further preferably 3% or more. By setting it to 25% or less, it is possible to prevent the acid resistance from being lowered. More preferably, it is 20% or less, more preferably 15% or less, and particularly preferably 10% or less.

[White phase separation glass]
White phase-separated glass has a fine phase-separated structure inside the glass, and is excellent in mechanical strength and scratch resistance.

  Glass phase separation means that a single-phase glass is divided into two or more glass phases. Examples of the method of phase separation of glass include a method of heat-treating glass after molding, or a method of maintaining glass at a phase separation temperature or higher before molding.

  As a condition for heat treatment for phase separation of the glass, typically, a temperature 50 to 400 ° C. higher than the glass transition point or the annealing point is preferable. A temperature higher by 100 ° C to 300 ° C is more preferable. The time for heat-treating the glass is preferably 1 to 64 hours, more preferably 2 to 32 hours. From the viewpoint of mass productivity, it is preferably 24 hours or less, and more preferably within 12 hours.

  As a method for holding the glass at a temperature higher than the phase separation temperature before molding, a method in which the glass is held at a temperature lower than the phase separation start temperature and higher than 1000 ° C. for phase separation is preferable. Since the phases are separated at a high temperature, whitening can be achieved in a short time. More preferably, it is 1100 degreeC or more, More preferably, it is 1200 degreeC or more.

  Whether or not the glass is phase-separated can be determined by SEM (scanning electron microscope). That is, when the glass is phase-separated, it can be observed that it is divided into two or more phases when observed with an SEM.

  Examples of the white phase separation glass include white binodal phase separation glass or white spinodal phase separation glass, and white binodal phase separation glass is preferable from the viewpoint of antifouling property or weather resistance.

  Next, the composition of the white phase-separated glass used in the present invention will be described.

In the present invention, SiO ₂ is a basic component that forms a network structure of white phase-separated glass. That is, it has an amorphous structure and exhibits excellent mechanical strength, weather resistance, or gloss as glass. The content of SiO ₂ is preferably 45 to 75%. More preferably, it is 50% or more, more preferably 55% or more, and particularly preferably 57% or more. Further, it is more preferably 70% or less, and further preferably 65% or less.

By making the content of SiO ₂ 45% or more, weather resistance and scratch resistance as glass can be improved. On the other hand, it can prevent that the melting temperature of glass becomes high by setting it as 75% or less.

B ₂ O ₃ is not an essential component, but may be contained up to 8% in order to increase the meltability of the glass, improve the whiteness of the glass, and further improve the weather resistance. More preferably, it is 7% or less, More preferably, it is 6% or less. By making the content of B ₂ O ₃ 8% or less, it is possible to prevent unevenness in whiteness.

Al ₂ O ₃ has the effect of improving the weather resistance of the glass, and significantly improving the dispersion stability of SiO ₂ and other components and imparting the function of uniforming the phase separation of the glass. The content of Al ₂ O ₃ is preferably 0 to 10%. More preferably, it is 1% or more, and further preferably 2% or more. Further, it is more preferably 8% or less, 7% or less, further preferably 6% or less, and particularly preferably 5% or less.

When Al ₂ O ₃ is contained, the content is more preferably 1% or more. The content of Al ₂ O ₃ by 1% or more, the effect can be sufficiently obtained. By setting it to 10% or less, it is possible to prevent the melting temperature of the glass from becoming high, to easily cause phase separation, and to prevent the reflectance from becoming low.

MgO is not essential, but may be contained in a range of up to 18% in order to improve the whiteness by facilitating phase separation in combination with SiO ₂ and Na ₂ O. More preferably, it is 3% or more, more preferably 5% or more, and particularly preferably 7% or more.

  By setting the content of MgO to 18% or less, it is possible to prevent a decrease in whiteness. More preferably, it is less than 11%, 10% or less, and more preferably 9% or less. When MgO is contained, the content is preferably more than 0.5%. The effect can be sufficiently obtained when the content exceeds 0.5%.

  CaO, SrO and BaO are not essential, but are components having an effect of increasing the whiteness, and any one or more of them may be contained.

  When CaO is contained, its content is preferably 1% or more, more preferably 2% or more. Moreover, it is preferable that it is 10% or less, More preferably, it is 8% or less, More preferably, it is 6% or less. By setting the content of CaO to 10% or less, it is possible to prevent crystals from being precipitated in the process of melting and molding glass.

  When SrO is contained, its content is preferably 1% or more, more preferably 2% or more, and preferably 10% or less, more preferably 8% or less. By setting the SrO content to 10% or less, it is possible to prevent crystals from being precipitated in the process of melting and molding the glass.

  When BaO is contained, its content is preferably 1% or more, more preferably 3% or more, further preferably 5% or more, and preferably 12% or less, more preferably 10% or less, Preferably it is 9% or less. By setting the BaO content to 12% or less, it is possible to prevent crystals from being precipitated in the process of melting and molding the glass. BaO is more effective in promoting whiteness than other alkaline earth metal oxides.

  The total content of these components, CaO + SrO + BaO, is preferably 0 to 20%, more preferably 15% or less, still more preferably 13% or less, and particularly preferably 12% or less. By making CaO + SrO + BaO 1% or more, a sufficient content effect can be obtained. More preferably, it is 2% or more, further preferably 3% or more, and particularly preferably 5% or more. In addition, it is preferable that CaO + SrO + BaO is 20% or less because it is possible to prevent crystals from being precipitated in the process of melting and forming glass.

  The total RO of MgO, CaO, SrO and BaO is preferably 4% or more, so that it is possible to prevent the dissolution temperature from becoming high, more preferably 6% or more, still more preferably 8% or more, particularly Preferably it is 10% or more. The content is preferably 25% or less because it is possible to prevent crystals from being precipitated in the process of melting and molding glass, more preferably 22% or less, and still more preferably 20% or less.

ZrO ₂ is not essential, but may be preferably contained up to 5% in order to improve the weather resistance. By making the content of ZrO ₂ 5% or less, it is possible to prevent a decrease in whiteness, more preferably 4% or less, and even more preferably 3% or less. When ZrO ₂ is contained, the content is preferably 0.5% or more. By setting it to 0.5% or more, a sufficient content effect can be obtained.

The content of Na ₂ O is preferably 3 to 15%, more preferably 5% or more, further preferably 8% or more, and particularly preferably 9% or more. More preferably, it is 14% or less, More preferably, it is 13% or less. Na ₂ O has an effect of improving the meltability of the glass, and is preferably 5% or more because a sufficient content effect can be obtained. Moreover, by setting it as 15% or less, since it can prevent that the weather resistance of glass falls and whiteness can fall, it is preferable. In particular, when it is desired to have whiteness, it is preferably 12% or less, more preferably 11% or less.

P ₂ O ₅ is a component that significantly promotes whitening of the glass and is preferably contained. By setting the content of P ₂ O ₅ to 1% or more, the whiteness of the glass becomes sufficient, preferably 2% or more, and more preferably 3% or more. On the other hand, by setting it to 10% or less, volatilization is less likely to occur, white color unevenness is reduced, and the aesthetics of the glass can be maintained, which is preferable, more preferably 8% or less, and even more preferably 7% or less. is there.

The glass of the present invention consists essentially of the above components, but other components may be used as long as the object of the present invention is not impaired. In that case, the total of such components should be 9% or less. preferable. The total content of 10 components of SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , MgO, CaO, SrO, BaO, ZrO ₂ , Na ₂ O and P ₂ O ₅ is 90% or more. Preferably, it is typically 94% or more.

  Examples of components other than the above components include the following.

La ₂ O ₃ and Nb ₂ O ₅ have the effect of improving the whiteness of the glass and may be contained in a range of 5% or less. By setting it to 5% or less, the glass can be prevented from becoming brittle. More preferably, it is 3% or less, More preferably, it is 2% or less.

  Further, as a coloring component, for example, Co, Mn, Fe, Ni, Cu, Cr, V, Zn, Bi, Er, Tm, Nd, Sm, Sn, Ce, Pr, Eu, Ag, or Au may be contained. Good. In that case, it is preferable that the sum of these coloring components is typically 5% or less in terms of mol% on the basis of the minimum valence oxide.

  Although the composition range of the preferred white phase-separated glass has been exemplified, those satisfying the purpose of the object of the present invention are included in the present invention even if the composition is other than the above.

  From the viewpoint of reflection, the average size of one phase in the phase separation state or the average particle size of the dispersed phase in the phase-separated glass is preferably 40 to 5000 nm, more preferably 50 to 3000 nm, and more preferably 100 to 2000 nm. More preferably it is.

  The average particle size of the dispersed phase can be measured by SEM observation. Here, the average size of one phase in the phase separation state is the average of the widths of the phases intertwined with each other in the spinodal state, and when one phase is spherical in the binodal state When the diameter of one phase is elliptical, it is the average value of the major axis and the minor axis. The average particle size of the dispersed phase is the average size in the binodal state.

[White crystallized glass]
Examples of white crystallized glass include crystallized glass containing nepheline solid solution crystal (hereinafter also referred to as nepheline crystallized glass), crystallized glass having β-spodumene or β-spodumene solid solution as a main crystal (hereinafter also referred to as spodomen crystallized glass). Crystallized glass on which crystals of β-quartz solid solution, forsterite (2MgO.SiO ₂ ), garnite (ZnO.Al ₂ O ₃ ), etc. are deposited. In addition, the white crystallized glass of the present invention is crystallized glass obtained by growing crystals in a glass obtained by melting, and the crystals to be precipitated are not limited to the crystals described above.

White crystallized glass can be produced through heat treatment of the precursor. In the manufacture of crystallized glass, the following steps (i) to (iii) are included.
(I) A glass-forming batch that normally contains a nucleating agent is melted at 1400-1750 ° C.
(Ii) The melt is cooled to a temperature below its glass transition temperature to form a glass of the desired shape.
(Iii) The glass is subjected to a prescribed heat treatment method to crystallize the glass.

  The step (iii) is divided into the following two steps (iii-1) and (iii-2).

(Iii-1) First, the raw glass is heated to a glass transition temperature or slightly higher than that to form nuclei in the glass. As a condition of the heat treatment for generating nuclei in the glass, the temperature is 950 ° C. Or less, more preferably 900 ° C. or less. Further, the heat treatment time is preferably 1 to 10 hours, and more preferably 2 to 6 hours.

(Iii-2) A step of heating the glass to a higher temperature, sometimes higher than its softening point, and growing a crystal on the nucleus formed in (iii-1) Conditions for heat treatment to grow the crystal As for temperature, it is preferred that it is 850-1200 ° C, and it is more preferred that it is 900-1150 ° C. Further, the heat treatment time is preferably 1 to 10 hours, and more preferably 2 to 6 hours.

  Nucleation and crystal growth may be performed simultaneously, and only one of (iii-1) and (iii-2) may be performed.

  In the crystallization mechanism, since crystals substantially grow on innumerable nuclei formed in advance, crystals containing a microstructure including relatively uniformly sized microcrystals uniformly dispersed in the glass matrix are included. Crystallized glass is obtained and can have reflective performance suitable for interiors of tunnels or tunnels.

(Nephrin crystallized glass)
Nepheline solid solution crystals are crystals represented by the formula _{Na 8-x K x Al 8} Si 8 O 32 ( the formula x varies from 0-8). When x is 8, it is a calcilite crystal. Typically, 10-90% of crystallized glass containing nepheline solid solution crystals is crystalline.

The crystal phase that appears in nepheline solid solution crystals depends on the glass composition and the heat treatment applied to the glass. “Nephelin” refers to a natural mineral having a crystal structure belonging to the hexagonal system and identified by the general chemical formula Na _8−x K _x Al ₈ Si ₈ O ₃₂ . However, the mineral nepheline exists as a broad solid solution and has not been fully elucidated (Geophical Laboratory, Paper No 1309, 'Nepheline Solid Solutions').

  The same applies to crystallized glass containing nepheline solid solution crystals, and the range of solid solutions is even wider because crystal growth occurs under unbalanced conditions. Therefore, metastable crystal glass can grow. The crystal phase of crystallized glass containing nepheline solid solution crystals may change substantially, and these crystals show a common diffraction peak with nepheline solid solution crystals in X-ray diffraction analysis, but the peak spacing and intensity are the same as those of the crystal phase. It may vary depending on the nature.

The crystallized glass containing nepheline solid solution crystals preferably contains Na ₂ O. The content of Na ₂ O in the crystallized glass containing nepheline solid solution crystals is preferably 10 to 30%, more preferably 12 to 24%, and still more preferably 15 to 20%.

SiO ₂ and Al ₂ O ₃ are the main components of nepheline solid solution and are essential. The content of SiO ₂ in the crystallized glass containing nepheline solid solution crystals is preferably 40 to 70%, and more preferably 45 to 64%. The content of Al ₂ O ₃ in the crystallized glass containing nepheline solid solution crystals is preferably 8 to 28%, more preferably 15 to 25%, and still more preferably 20 to 24%.

Any one of TiO ₂ , ZrO ₂ , SnO ₂ , ZnO and P ₂ O ₅ is essential as a nucleating agent in the crystallized glass containing nepheline solid solution crystals.

  The content of the nucleating agent in the crystallized glass containing nepheline solid solution crystals is preferably 1 to 12%, and more preferably 2 to 10%.

The crystallized glass containing nepheline solid solution crystals may contain K ₂ O, preferably 2% or more, preferably 10% or less, more preferably 8% or less. K ₂ O is a component that forms nepheline solid solution crystals and is a component that improves meltability. The content of K 2 _O can be prevented from weathering resistance is lowered by 10% or less.

  The reflectance of crystallized glass containing nepheline solid solution crystals can be adjusted by adjusting the glass composition and crystallization treatment conditions.

  Co, Mn, Fe, Ni, Cu, Cr, V, Zn, Bi, Er, Tm, Nd, Sm, Sn, Ce, Pr, Eu, Ag or Au are added to the white crystallized glass as coloring components. May be. When adding, it is preferable to set it as 5% or less by mol% display of an oxide basis.

(Spodumene crystallized glass)
Spodumene crystallized glass is crystallized glass whose main crystal is β-spodumene or β-spodumene solid solution.

The composition of the spodumene crystallized glass is a component that forms a skeleton of SiO ₂ glass as an oxide in the glass forming batch and constitutes a crystal, and its content is preferably 50 to 75%, more preferably. Is 60-70%. When SiO ₂ is 50% or more, unintended crystal precipitation is suppressed in the melting process, and production is facilitated. Moreover, by being 75% or less, the glass can be easily melted without excessively increasing the viscosity of the glass.

Al ₂ O ₃ is a component that forms a skeleton of glass and constitutes crystals, and its content is preferably 1 to 25%, more preferably 5 to 20%. By making Al ₂ O ₃ 25% or less, the glass can be easily melted without excessively increasing the viscosity of the glass.

B ₂ O ₃ has the effect of lowering the liquidus temperature of the glass, and its content is preferably 0 to 8%, more preferably 1 to 5%. By making B ₂ O ₃ 8% or less, it is possible to prevent the glass transition point from being lowered.

Li ₂ O is a crystal component, has a large effect on crystallinity and has a function of reducing the viscosity of glass, and its content is preferably 3 to 18%, more preferably 5 to 15%. It is. By making Li ₂ O 18% or less, it becomes difficult to precipitate unintended crystals in the process of melting glass.

Na ₂ O is a component that improves the meltability of the glass, and its content is preferably 0 to 10%, more preferably 0.5 to 5%.

K ₂ O is a component that improves the meltability of the glass and adjusts the coefficient of thermal expansion, and its content is preferably 0 to 10%, more preferably 0.5 to 5%. The content of MgO is preferably 0 to 16%, more preferably 1 to 10%.

P ₂ O ₅ , TiO ₂ or ZrO ₂ is a component that works as a nucleation accelerator and improves the crystallinity of the glass. Either one or the total amount, the content is preferably 1 to 8%, more preferably 2 to 5%. By setting it to 1% or more, it functions sufficiently as a nucleation accelerator. By setting it to 8% or less, unintentional precipitation of crystals in the melting process is suppressed, and melting of the glass becomes easy.

  Further, as a coloring component, for example, Co, Mn, Fe, Ni, Cu, Cr, V, Zn, Bi, Er, Tm, Nd, Sm, Sn, Ce, Pr, Eu, Ag, or Au may be contained. Good. In that case, it is preferable that the sum of these coloring components is typically 5% or less in terms of mol% on the basis of the minimum valence oxide.

  Usually, as a method for forming the above-mentioned spodumene crystallized glass, a raw material is first prepared so as to be a glass having a desired composition, and this is preferably melted at 1400 to 1750 ° C., and then a desired shape. A crystalline glass molded body is produced by molding into a glass.

  Next, the obtained crystalline glass molded body is preferably held at 600 to 900 ° C., preferably for 0.5 to 5 hours to perform nucleation, and is preferably a crystallized glass containing β-spodumene solid solution. The crystal (β-spodumene solid solution) is precipitated in the glass by heat treatment at 800 to 1200 ° C., preferably for 0.5 to 3 hours.

The white glass of the present invention preferably has a density of 3.0 g / cm ³ or less, more preferably 2.8 g / cm ³ or less. When the density is 3.0 g / cm ³ or less, the weight can be reduced.

  The white glass of the present invention preferably does not contain filler mixed glass. When the filler mixed glass is contained, the mixing amount is preferably 1% or less. Here, the filler is a ceramic powder or a crystal powder, and the filler mixed glass is obtained by mixing a filler with glass and heat-molding it. In addition, the crystal | crystallization which precipitated from the uniform glass obtained by fuse | melting is not contained in a filler.

  Examples of the filler include aluminum nitride, zirconia oxide, zircon, and titanium oxide. The filler-mixed glass is easy to contain bubbles, and the strength may be reduced by stress due to the difference in thermal expansion between the filler and the mother glass. By not containing the filler mixed glass, the strength of the glass can be improved.

White glass of the present invention preferably has acid resistance (20 hours 0.1 M HCl treatment at 90 ° C.) is 2 mg / cm ² or less, more preferably 1 mg / cm ² or less, 0.5 mm or less More preferably. Improves resistance to sulfur oxide (SO _X ) or nitrogen oxide (NO _X ) contained in exhaust gas when acid resistance (0.1 M HCl treatment at 90 ° C. for 20 hours) is 2 mg / cm ² or less can do.

White glass of the present invention is preferably alkali resistance (90 ° C. for 20 hours 0.1 M NaOH treated) is 2 mg / cm ² or less, and more preferably 1 mg / cm ² or less. When the alkali resistance (0.1 M NaOH treatment at 90 ° C. for 20 hours) is 2 mg / cm ² or less, it is possible to improve resistance to alkali components eluted from the concrete or the like used on the wall surface.

  The white glass of the present invention preferably has a bending strength of 60 MPa or more, more preferably 80 MPa or more. When the bending strength is 60 MPa or more, sufficient strength against the deformation of the wall surface due to the collision of the vehicle or deterioration over time can be obtained. The bending strength is measured by a three-point bending test as will be described later in Examples.

  The white glass of the present invention is typically plate-shaped. Moreover, you may shape | mold not only flat form but curved surface form. In this case, the glass formed into a flat plate or a block may be reheated and softened in its own weight, or may be press-molded. Moreover, you may shape | mold into a desired shape by what is called a direct press method which flows out and press-molds a molten glass directly on a press die.

  The surface of the white glass of the present invention may be a flat surface or an uneven pattern. The uneven pattern may be sandwiched between rollers in which the glass is soft and the surface is uneven, or the uneven pattern may be formed by pressing. Further, the surface may be a mirror surface, or may be ground glass by polishing powder or etching.

  The white glass of the present invention is typically not chemically strengthened, but may be chemically strengthened or physically strengthened. By strengthening, the strength can be further increased.

  The white glass of the present invention preferably has a lightness L * of 85 or more in the CIE 1976 color system based on JIS Z8729 (2004). More preferably, it is 90 or more. When L * is 85 or more, you can feel brighter. The chromaticity a * is preferably -6 to +6, more preferably -3 to +3. The chromaticity b * is preferably −6 to +6, more preferably −3 to +3. When the chromaticities a * and b * are −6 to +6, white glass having high design properties and white color can be obtained.

[Production of glass]
Example 1 (white phase-separated glass), Example 2 (white crystallized glass) and Example 3 (white crystallized glass) having the composition shown in Table 1 were prepared by the following method.

(Example 1: white phase separation glass)
Glass raw materials were appropriately selected, and weighed and mixed so as to give 300 g as a glass having the composition shown in Example 1 of Table 1. Next, it was placed in a platinum crucible, placed in a 1600 ° C. resistance heating electric furnace, melted for 3 hours, defoamed and homogenized, then cooled to 1360 ° C. over 10 minutes and held for 30 minutes. Thereafter, it was poured into a mold material, held at a temperature about 30 ° C. higher than the glass transition point for 1 hour, and then cooled to room temperature at a cooling rate of 1 ° C. per minute to obtain a white phase-separated glass.

(Example 2: White crystallized glass)
Glass raw materials were appropriately selected, and weighed and mixed so as to give 300 g as a glass having the composition shown in Example 2 of Table 1. Next, it is placed in a platinum crucible, placed in a resistance heating electric furnace at 1650 ° C., melted for 3 hours, defoamed and homogenized, poured into a mold material, and heated at a temperature about 30 ° C. higher than the glass transition point for 1 hour. After holding, transparent glass was obtained by cooling to room temperature at a cooling rate of 1 ° C. per minute. The obtained glass was again put into a resistance heating type electric furnace, heated to 850 ° C. at a heating rate of 10 ° C./min, held at 850 ° C. for 4 hours, and further 1100 at a heating rate of 10 ° C./min. After raising the temperature to 1 ° C., it was held at 1100 ° C. for 4 hours, and cooled to room temperature at a cooling rate of 10 ° C. per minute to obtain white nepheline crystallized glass.

(Example 3: White crystallized glass)
Glass raw materials were appropriately selected, and weighed and mixed so as to give 300 g as a glass having the composition shown in Example 3 of Table 1. Next, it is placed in a platinum crucible, placed in a resistance heating electric furnace at 1650 ° C., melted for 3 hours, defoamed and homogenized, poured into a mold material, and heated at a temperature about 30 ° C. higher than the glass transition point for 1 hour. After holding, transparent glass was obtained by cooling to room temperature at a cooling rate of 1 ° C. per minute. The obtained glass was heated to 830 ° C. at a heating rate of 10 ° C. per minute, held at 830 ° C. for 4 hours, further heated to 925 ° C. at a heating rate of 10 ° C. per minute, and then increased to 925 ° C. For 9 hours, and cooled to room temperature at a cooling rate of 10 ° C. per minute to obtain white spodumene crystallized glass.

〔Evaluation method〕
(1) Total light reflectance The total light reflectance of the white glass whose thickness is 1 mm and 3 mm was measured with a Lambda 950 ultraviolet visible near infrared spectrophotometer manufactured by PerkinElmer in accordance with JIS R 3106 (1998). The total light reflectance at a wavelength of 600 nm is represented by R ₆₀₀ , the maximum total light reflectance in the visible light region (400 to 800 nm) is represented by R _max , and the minimum total light reflectance is represented by R _min .
(2) Density Density was measured by the Archimedes method.
(3) Young's modulus Young's modulus was measured by an ultrasonic pulse method on a glass plate having a thickness of 4 to 10 mm and a size of about 40 mm x 40 mm.
(4) Acid resistance The acid resistance was determined by measuring the mass loss per surface area after the glass was immersed in a 0.1 M HCl aqueous solution at 90 ° C. for 1 hour or 20 hours. The surface area was defined as the glass surface area before the test, and the weight loss before and after the test was divided by the surface area to determine the mass loss per unit area.
(5) Alkali resistance The alkali resistance measured the mass loss per surface area after glass was immersed in 0.1M NaOH aqueous solution at 90 degreeC for 1 hour or 20 hours. The surface area was defined as the glass surface area before the test, and the weight loss before and after the test was divided by the surface area to determine the mass loss per unit area.
(6) Bending strength The bending strength is 3 under the conditions of a cross-head speed of 0.5 mm / min and a support stand span of 30 mm at room temperature using a glass plate in which both sides of a sample shape of 40 × 5 × 1 mm are mirror-polished with cerium oxide. It was measured by a point bending test.
(7) Chromaticity A sample having a size of about 30 mm × about 30 mm, a thickness of 1 mm, and mirror-finished upper and lower surfaces was produced. The chromaticity (L *, a *, b *) values indicating hue and saturation are standardized by CIE (International Lighting Commission) and standardized by JIS [JIS Z8729 (2004)]. * B * In a colorimeter (color i7, manufactured by X-Rite Co.) based on the color system measurement, with a D65 light source, L * = 98.44, a * = − 0.20, b * = 0 1 mm thick glass was placed on a white standard plate [Everz Corporation, Ever-WHlTE (Code No. 9582)].

  The results are shown in Table 2.

  The glass plates mirror-polished to 40 × 5 mm with a thickness of 1 mm in Examples 1 to 3 were chemically strengthened. Table 3 shows the ion exchanged molten salt, the molten salt temperature, and the ion exchange time. The bending strength of the ion-exchanged white glass was measured at room temperature by a three-point load method under the conditions of a crosshead speed of 0.5 mm / min and a support stand span of 30 mm. The results are shown in Table 3.

From the results shown in Table 2, it was found that the white glass of the present invention was excellent in acid resistance and alkali resistance. In particular, the acid resistance and alkali resistance of Example 1 which is a white phase-separated glass are 0.1 mg / cm ² or less and 0.3 mg / cm ² or less, respectively.

  In addition, the total light reflectance at a wavelength of 600 nm is 50% or more and the bending strength is 60 MPa or more, and it was found that the white glass of the present invention has excellent characteristics in terms of reflection performance and strength.

  Moreover, as shown in Table 3, the bending strength of the chemically strengthened white glass was 500 MPa or more, and it was found that the glass had excellent characteristics in terms of strength.

Claims (10)

  White glass for interiors of tunnels or tunnels with a thickness of 0.5 mm or more. The white glass for interior of a mine tunnel or a tunnel according to claim 1, wherein the total light reflectance R ₆₀₀ of light having a wavelength of 600 nm is 50% or more.   The white glass for interior of a mine tunnel or a tunnel according to claim 1 or 2, wherein the white glass is white phase-separated glass.   The white glass for interior of a mine tunnel or a tunnel according to claim 3, wherein the white phase-separated glass is a white binodal phase-separated glass. The white glass for interior of a mine tunnel or a tunnel according to any one of claims 1 to 4, comprising 0 to 25% of Al ₂ O ₃ in terms of a mole percentage based on the following oxide. The white glass for interior of a mine tunnel or a tunnel according to any one of claims 1 to 5, wherein the density is 3.0 g / cm ³ or less.   The white glass for interior of a mine tunnel or a tunnel according to any one of claims 1 to 6, which does not contain filler mixed glass.   The white glass for interior of a mine tunnel or a tunnel according to any one of claims 1 to 7, wherein the thickness is 30 mm or less. The white glass for interior of a mine tunnel or a tunnel according to any one of claims 1 to 8, wherein the acid resistance (0.1 M HCl treatment at 90 ° C for 20 hours) is 2 mg / cm ² or less.   The white glass for interior of a mine tunnel or a tunnel according to any one of claims 1 to 9, wherein the bending strength is 60 MPa or more.