Spacer and multi-layered glass

Abstract

A spacer according to the present disclosure is interposed between a first glass substrate and a second glass substrate opposing each other, and is disposed in contact with the first glass substrate and the second glass substrate. The spacer according to the present disclosure is provided with: a first contact surface disposed in contact with the first glass substrate; a second contact surface disposed in contact with the second glass substrate; and a lateral surface located between the first contact surface and the second contact surface. The mean value RΔq1 of root mean square slopes in a roughness curve of the first contact surface is less than the mean value RΔq2 of root mean square slopes in a roughness curve of the lateral surface.

Description

Spacers and double glazing

[0001] The present disclosure relates to a spacer used in double glazing in which a pair of glass substrates are laminated with a reduced pressure internal space therebetween, and to double glazing.

[0002] Conventionally, double-glazing has been known in which a pair of glass substrates are arranged opposite each other, and the outer peripheries of both glass substrates are sealed with a sealant to create an internal space, and the pressure is reduced by evacuating the air inside the space. For example, Patent Document 1 discloses a plurality of spacers interposed in the internal space between the pair of glass substrates in the double-glazing.

[0003] JP 2018-104280 A

[0004] The spacer of the present disclosure is interposed between a first glass substrate and a second glass substrate facing each other and is disposed in contact with the first and second glass substrates. The spacer of the present disclosure includes a first contact surface disposed in contact with the first glass substrate, a second contact surface disposed in contact with the second glass substrate, and a side surface located between the first and second contact surfaces. The average value RΔq1 of the root-mean-square slope of the roughness curve of the first contact surface is smaller than the average value RΔq2 of the root-mean-square slope of the roughness curve of the side surface.

[0005] Fig. 3A is a schematic cross-sectional view of a double-glazing unit according to an embodiment of the present disclosure. Fig. 4B is a schematic plan view of a first glass substrate having a plurality of spacers attached to its surface in the double-glazing unit shown in Fig. 1. Fig. 5A is a schematic plan view of a second glass substrate in the double-glazing unit shown in Fig. 1. Fig. 6A is a plan view of a spacer according to an embodiment of the present disclosure. Fig. 7A is a side view of Fig. 3A. Fig. 7B is a plan view of a spacer according to an embodiment of the present disclosure. Fig. 8A is a side view of Fig. 8A. Fig. 9A is a plan view of a spacer according to an embodiment of the present disclosure.

[0006] If the spacer 3, which is disposed at a predetermined distance between the first glass substrate 1 and the second glass substrate 2 (hereinafter, sometimes referred to as a pair of glass substrates 1 and 2), becomes misaligned due to vibration or other factors, the first glass substrate 1 or the second glass substrate 2 is likely to warp. Repeatedly heating and heating these glass substrates in a warped state can easily reduce the durability of the double-glazing unit 100. If particles adhering to the surface of the first glass substrate 1 or the second glass substrate 2 become airborne due to vibration or other factors and adhere to the side surface 300 of the spacer 3, light entering the double-glazing unit 100 is likely to be scattered by the side surface 300 of the spacer 3. As a result, visibility when viewing an object through the double-glazing unit 100 can easily be reduced.

[0007] In the spacer 3 of the present disclosure, the average value RΔq1 of the root-mean-square slope of the roughness curve of the first contact surface 301 is smaller than the average value RΔq2 of the root-mean-square slope of the roughness curve of the side surface 300. As a result, it is possible to reduce misalignment of the spacer 3 and improve the durability of the double-glazing glass 100. It is also possible to reduce particle adhesion to the side surface 300 of the spacer 3 and improve visibility when viewing objects through the double-glazing glass 100.

[0008] Hereinafter, a double glazing spacer 3 and a double glazing unit 100 according to an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view of the double glazing unit 100, and Figs. 2A and 2B are schematic plan views showing a state in which a plurality of spacers 3 are attached to the surface of a first glass substrate 1.

[0009] As shown in FIG. 1 , the double-glazed glass 100 according to this embodiment includes a first glass substrate 1, a second glass substrate 2 disposed opposite the first glass substrate 1, a spacer 3 interposed between the first glass substrate 1 and the second glass substrate 2, an internal space 4 located between the first glass substrate 1 and the second glass substrate 2, a peripheral edge 5 of the first glass substrate 1, a seal 6 that seals the peripheral edge 5, and an exhaust pipe 7 for evacuating the internal space 4.

[0010] The first glass substrate 1 and the second glass substrate 2 are, for example, rectangular, flat glass plates. Examples of the first glass substrate 1 and the second glass substrate 2 include float glass such as tempered glass. The thickness of the first glass substrate 1 and the second glass substrate 2 is, for example, 1 mm or more and 5 mm or less. As shown in FIG. 2B , the second glass substrate 2 has the same dimensions as the first glass substrate 1.

[0011] The spacer 3 is disposed in an internal space 4 located between the pair of glass substrates 1 and 2, and is in contact with the pair of glass substrates 1 and 2, thereby maintaining the internal space 4. A plurality of spacers 3 are disposed, for example, at predetermined intervals between the first glass substrate 1 and the second glass substrate 2. The spacers 3 are disposed at intervals of, for example, 1 to 3 cm.

[0012] 2A, the spacers 3 are placed at predetermined intervals on the surface of the first glass substrate 1. At this time, the surface of the first glass substrate 1 is held horizontally. Therefore, when the spacers 3 are placed at predetermined positions on the surface of the first glass substrate 1, the spacers 3 are prevented from moving inadvertently.

[0013] The internal space 4 is a space surrounded by the first glass substrate 1, the second glass substrate 2, and the seal portion 6. The internal space 4 is placed in a vacuum state or a reduced pressure state by being exhausted through an exhaust pipe 7. This reduces heat exchange between the first glass substrate 1 and the second glass substrate 2, thereby improving the thermal insulation of the double glazing 100. The reduced pressure state can be achieved, for example, by -5 Pa or more 10 -1 Pa or less.

[0014] The seal portion 6 is located on the peripheral edge 5 of the first glass substrate 1. The seal portion 6 is located, for example, around the entire periphery of the peripheral edge 5 of the first glass substrate 1 and surrounds the internal space 4. The height of the seal portion 6 is, for example, the same as the height of the spacer 3. The seal portion 6 is made of, for example, a low-melting-point glass frit. Examples of low-melting-point glass frits that can be used as a sealing material include bismuth-based seals and frit pastes containing 70% by mass or more of Bi2O3, 15% by mass or less each of B2O3 and ZnO, and 5% by mass or more of a mixture of organic substances such as ethyl cellulose and terpineol.

[0015] The seal portion 6 can be formed, for example, by the following method. A sealant is applied to the peripheral edge portion 5 of the first glass substrate 1 using a dispenser, and then dried. Next, the second glass substrate 2 is placed opposite the first glass substrate 1, and in this state, the pair of glass substrates 1 and 2 are placed in a furnace and heated to melt a low-melting-point glass frit, sealing the peripheries of the pair of glass substrates 1 and 2 to form the seal portion 6. The seal portion 6 is formed, for example, by applying glass frit and then heating and melting it.

[0016] The exhaust pipe 7 exhausts the internal space 4 and places the internal space 4 in a vacuum or reduced pressure state. The exhaust pipe 7, for example, penetrates the second glass substrate 2 in the thickness direction.

[0017] As shown in Figures 3A and 3B, the spacer 3 of this embodiment has a first contact surface 301 that is arranged in contact with the first glass substrate 1, a second contact surface 302 that is arranged in contact with the second glass substrate 2, and a side surface 300 that is located between the first contact surface 301 and the second contact surface 302.

[0018] The average value RΔq1 of the root-mean-square slope of the roughness curve of the first contact surface 301 is smaller than the average value RΔq2 of the root-mean-square slope of the roughness curve of the side surface 300. As a result, when the average value RΔq1 of the root-mean-square slope of the roughness curve of the first contact surface 301 is small, the slope of the unevenness of the first contact surface 301 is small. Therefore, the actual contact area with the first glass substrate 1 is increased, and the contact resistance is increased, thereby reducing misalignment of the spacer 3. This reduces deflection of the first glass substrate 1 and improves the durability of the double-glazed glass 100 even when subjected to repeated elevated temperatures.

[0019] Furthermore, the average value RΔq2 of the root-mean-square slope in the roughness curve of the side surface 300 is large. Therefore, the slope of the unevenness of the surface shape of the side surface 300 becomes large. As a result, when particles adhering to the surfaces of the first glass substrate 1 and the second glass substrate 2 become airborne, adhesion of these airborne particles to the side surface 300 can be reduced. This reduces scattering of light entering the internal space 4 at the side surface 300 of the spacer 3, and improves visibility when viewing objects through the double-glazed glass 100.

[0020] Similar to the first contact surface 301, the average root mean square slope RΔq3 of the roughness curve of the second contact surface 302 may be smaller than the average root mean square slope RΔq2 of the roughness curve of the side surface 300. As a result, the same effect as that of the first end 3211 can be obtained.

[0021] The average values ​​of the root-mean-square slopes RΔq1 and RΔq3 are, for example, 0.01 or more and 0.29 or less. The average value of the root-mean-square slope RΔq2 is, for example, 0.3 or more and 0.7 or less. The difference between the average values ​​of the root-mean-square slopes RΔq1 and RΔq3 and the average value of the root-mean-square slope RΔq2 is, for example, 0.05 or more and 0.65 or less.

[0022] The root-mean-square slope of the roughness curves of the side surface 300, the first contact surface 301, and the second contact surface 302 can be measured in accordance with JIS B0601:2001 using a laser microscope (Keyence Corporation, Ultra-Deep Color 3D Shape Measuring Microscope (VK-X1000 or its successor model)). Measurement conditions include a coaxial illumination method, a measurement magnification of 480x, no cutoff value λs, a cutoff value λc of 0.08 mm, no cutoff value λf, end effect correction, and a measurement range of 710 μm × 533 μm for each surface. Four lines to be measured are then drawn at approximately equal intervals within each measurement range, and the line roughness is measured, and the average value of the root-mean-square slope is calculated. When the side surface 300 is the measurement target, the length of each line is, for example, 240 μm. When the first contact surface 301 and the second contact surface 302 are to be measured, the length of each line is, for example, 300 μm.

[0023] In the spacer 3 of this embodiment, the average value Rsk1 of kurtosis in the roughness curve of the first contact surface 301 is smaller than the average value Rsk2 of kurtosis in the roughness curve of the side surface 300. As a result, the average value Rsk1 of kurtosis in the roughness curve of the first contact surface 301 is large. Therefore, the kurtosis of the protrusions on the first contact surface 301 is reduced. As a result, the actual contact area with the first glass substrate 1 is increased, and the contact resistance is increased. As a result, the positional deviation of the spacer 3 can be further reduced. Therefore, the deflection of the first glass substrate 1 can be reduced, and the durability of the double-glazed glass 100 can be improved even when subjected to repeated elevated temperatures.

[0024] The increased kurtosis of the protrusions on the side surfaces 300 further reduces adhesion of particles adhering to the surfaces of the first glass substrate 1 and the second glass substrate 2 to the air, thereby further reducing the amount of the particles adhering to the side surfaces 300. This further reduces scattering of light entering the internal space 4 at the side surfaces 300 of the spacer 3. As a result, visibility when viewing an object through the double-glazed glass 100 can be further improved.

[0025] Similar to the first contact surface 301 , the average value Rsk3 of the kurtosis in the roughness curve of the second contact surface 302 may be smaller than the average value Rsk2 of the kurtosis in the roughness curve of the side surface 300 .

[0026] The average values ​​of kurtosis Rsk1 and Rsk3 are, for example, 0.6 or more and 3.1 or less. The average value of kurtosis Rsk2 is, for example, 1.7 or more and 5.6 or less. The difference between the average values ​​of kurtosis Rsk1 and Rsk3 and the average value of kurtosis Rsk2 is, for example, 1.5 or more and 4.5 or less. The kurtosis in the roughness curves of the side surface 300, the first contact surface 301, and the second contact surface 302 may be determined using the same measurement method as the above-mentioned method for measuring the root-mean-square slope.

[0027] In the spacer 3 of this embodiment, the side surface 300 is a fired surface. A fired surface is a surface in the as-fired state, without undergoing processing such as grinding or polishing after firing ceramics. This suppresses the formation of a crushed layer and reduces particle shedding from the side surface 300. As a result, particles floating in the internal space 4 of the double-glazed glass 100 are further reduced, and the light transmittance of the double-glazed glass 100 can be further improved.

[0028] The fact that side surface 300 is a fired surface can be confirmed by observing side surface 300 at 480x magnification using an ultra-deep color 3D shape measuring microscope (VK-X1000 or its successor model).

[0029] The spacer 3 of this embodiment may be, for example, a disk-shaped or flat plate-shaped spacer, or a cylindrical or polygonal column-shaped spacer. FIGS. 3A and 3B show an example in which the spacer 3 is disk-shaped. As shown in FIGS. 4A to 5B , the spacer 3 may further include a plate-shaped or columnar central portion 31, a first end portion 3211 protruding from the central portion 31, and a second end portion 3212 located opposite the first end portion 3211 and protruding from the central portion 31. The side surface 300 is located at the outer edge of the central portion 31, the first contact surface 322 is located on the first glass substrate 1 side of the first end portion 3211, and the second contact surface 323 is located on the second glass substrate 2 side of the second end portion 3212.

[0030] The central portion 31 has a plate shape, such as a disk or a flat plate, or a columnar shape, such as a cylindrical or polygonal prism. The first end portion 3211 and the second end portion 3212 have a plate shape, such as a disk or a flat plate. The first end portion 3211 and the second end portion 3212 have a tapered shape, such as a spherical crown shape, a spherical band shape, a truncated cone shape, or a truncated polygonal pyramid shape.

[0031] 4A and 4B show an example in which the central portion 31, the first end portion 3211, and the second end portion 3212 are flat-plate shaped. Figures 5A and 5B show an example in which the central portion 31 is disk-shaped, and the first end portion 3211 and the second end portion 3212 are spherical-crown shaped.

[0032] When the central portion 31 is flat or polygonal prism-shaped and the first end portion 3211 and the second end portion 3212 are flat, the width perpendicular to the height direction of the first end portion 3211 may be smaller than the width perpendicular to the height direction of the central portion 31, as shown in FIGS. 4A and 4B . As a result, the contact area between the first end portion 3211 and the first glass substrate 1 is reduced, thereby improving the thermal insulation of the double-glazing unit 100. The large width of the central portion 31 increases the mechanical strength of the spacer 3 and improves the reliability of the spacer 3. Similar to the first end portion 3211, the width perpendicular to the height direction of the second end portion 3212 may be smaller than the width perpendicular to the height direction of the central portion 31. Here, the width perpendicular to the height direction is the projected length of a cross section including the axis in the height direction.

[0033] Of the widths of the first end 3211 and the second end 3212 perpendicular to the height direction, the width at the position where they contact the central portion 31 is, for example, 0.37 mm or more and 0.64 mm or less. The width of the central portion 31 perpendicular to the height direction is, for example, 0.4 mm or more and 0.5 mm or less. However, the width of the central portion 31 perpendicular to the height direction is greater than the width of the first end 3211 and the second end 3212 perpendicular to the height direction at the position where they contact the central portion 31. The difference between the width of the central portion 31 perpendicular to the height direction and the width of the first end 3211 and the second end 3212 at the position where they contact the central portion 31 is, for example, 30 μm or more and 100 μm or less.

[0034] When the central portion 31 is disk-shaped or cylindrical, and the first end portion 3211 and the second end portion 3212 are spherical crown-shaped, spherical band-shaped, or truncated cone-shaped, the diameter of the first end portion 3211 perpendicular to the height direction may decrease from the central portion 31 side toward the opposite side, as shown in Fig. 5B . Similar to the first end portion 3211, the diameter of the second end portion 3212 perpendicular to the height direction may decrease from the central portion 31 side toward the opposite side.

[0035] Of the diameters of the first end 3211 and the second end 3212 perpendicular to the height direction, the diameter at the position where they contact the central portion 31 is, for example, 0.34 mm or more and 0.54 mm or less. The diameter of the central portion 31 perpendicular to the height direction is, for example, 0.37 mm or more and 0.64 mm or less. However, the diameter of the central portion 31 perpendicular to the height direction is larger than the diameters of the first end 3211 and the second end 3212 perpendicular to the height direction at the position where they contact the central portion 31. The difference between the diameter of the central portion 31 perpendicular to the height direction and the diameters of the first end 3211 and the second end 3212 at the positions where they contact the central portion 31 is, for example, 30 μm or more and 100 μm or less.

[0036] 5A and 5B , the first end 3211 may have a spherical crown shape. In this case, the first contact surface 322 has a curved shape, and a portion of the curved surface comes into contact with the first glass substrate 1. This reduces the contact area between the first end 3211 and the first glass substrate 1. Similar to the first end 3211, the second end 3212 may also have a spherical crown shape.

[0037] When the first end 3211 has a spherical crown shape, the radius of the sphere of the first contact surface 322 is preferably 0.8 mm to 1.6 mm. This range of radius can improve both the rigidity and heat insulation of the first end 3211. Even when the second end 3212 has a spherical crown shape, the radius of the second contact surface 323 is preferably within the above range.

[0038] The radii of the first contact surface 322 and the second contact surface 323 can be measured using a laser microscope (Keyence Corporation, Ultra-Deep Color 3D Shape Measuring Microscope (VK-X1100 or its successor model)). The measurement conditions are the same as those used to determine the root-mean-square slopes of the first contact surface 322 and the second contact surface 323, and profile measurement can be performed for each measurement range.

[0039] 4B and 5B , the height (h1) of the central portion 31 may be greater than the sum of the height (h2) of the first end portion 3211 and the height (h3) of the second end portion 3212. This can increase the mechanical strength of the spacer 3. By making the sum of the height (h2) of the first end portion 3211 and the height (h3) of the second end portion 3212 small, deflection of the spacer 3 can be suppressed.

[0040] The height (h1) of the central portion 31 is, for example, 0.14 mm or more and 0.18 mm or less. The sum of the height (h2) of the first end portion 3211 and the height (h3) of the second end portion 3212 is, for example, 0.02 mm or more and 0.06 mm or less. The height (h2) of the first end portion 3211 and the height (h3) of the second end portion 3212 may be the same.

[0041] In the spacer 3 of this embodiment, the area occupancy of the pores at the first end portion 3211 is greater than the area occupancy of the pores at the outer edge of the central portion 31. As a result, the contact area between the first glass substrate 1 and the spacer 3 is reduced, improving the thermal insulation of the double-glazing unit 100.

[0042] Because the area occupation rate of the pores at the outer edge of the central portion 31 is small, the side surface 300 located at the outer edge of the central portion 31 becomes dense. As a result, the mechanical strength of the side surface 300 can be maintained, and the mechanical strength of the spacer 3 can also be maintained. Because the mechanical strength of the side surface 300 is high, even if the side surface 300 comes into contact with the first glass substrate 1 or the second glass substrate 2 when attaching the spacer 3 to the double-glazing unit 100, the risk of particles falling off from the side surface 300 is further reduced. As a result, the number of particles floating in the internal space 4 of the double-glazing unit 100 can be further reduced, and the light transmittance of the double-glazing unit 100 can be further improved. Here, the outer edge of the central portion 31 refers to the region up to 20 μm in the width direction from the side surface 300.

[0043] In particular, it is preferable that the difference between the area occupancy rate of the pores at the first end 3211 and the area occupancy rate of the pores at the outer edge of the central portion 31 be 0.2% or more. In order to suppress particle shedding from the first contact surface 322 and particles generated from the pores and floating in the air, it is preferable that the first end 3211 be dense, and it is preferable that the area occupancy rate of the pores at the first end 3211 be 2% or less, and particularly 1% or less.

[0044] To measure the area occupancy of the pores, the average particle diameter D 50 The surface is polished on a tin plate using diamond abrasive grains with a diameter of 0.5 μm. The polished surface obtained by this polishing is photographed using a scanning electron microscope (SEM) at a magnification of 10,000 times, with the measurement range being, for example, 12 μm in horizontal length and 9 μm in vertical length. Next, the measurement range is set from the photographed image, and the pore area ratio can be obtained by analyzing using image analysis software (e.g., Win ROOF, manufactured by Mitani Shoji Co., Ltd.). In the analysis, the threshold value of the circle equivalent diameter of the pores is 0.21 μm, and circle equivalent diameters of less than 0.21 μm are not included in the calculation of the area occupancy ratio.

[0045] The spacer 3 of this embodiment is formed of a ceramic primarily composed of, for example, zirconium oxide, mullite, forsterite, cordierite, steatite, alkali metal aluminosilicate, aluminum titanate, or zinc oxide. By forming the spacer 3 from a ceramic, it is possible to reduce outgassing from the spacer 3. Furthermore, it is possible to maintain a high thermal insulation effect over a long period of time. The mechanical strength of the spacer 3 can be improved. The alkali metal aluminosilicate is, for example, β-spodumene. When the ceramic is primarily composed of zirconium oxide, it is preferable that the ceramic be translucent. An example of a translucent ceramic is a ceramic primarily composed of zirconium oxide in which lanthanum and a stabilizer such as calcium oxide, magnesium oxide, yttrium oxide, scandium oxide, or cerium oxide are solid-solved.

[0046] When the ceramic is primarily composed of zinc oxide, it may contain 1.9 to 3.8 mass% of Al, calculated as an oxide, out of 100 mass% of the components constituting the ceramic. By including Al in this range, it is possible to lower the sintering temperature and reduce the thermal conductivity. When the ceramic is primarily composed of eucryptotite, it may contain 20 mass% or less of Ti or Zr, calculated as an oxide, out of 100 mass% of the components constituting the ceramic. By including Ti or Zr in this range, it is possible to lower the thermal conductivity and increase the rigidity.

[0047] The spacer 3 may be a ceramic formed from a composite compound of aluminum oxide and zirconium oxide (hereinafter, ceramic formed from this composite compound may be referred to as a "composite ceramic"). For example, the composite ceramic contains 20% to 80% by mass of aluminum oxide and 80% to 20% by mass of zirconium oxide. The composite ceramic may contain Si, Ti, and Mg as oxides, with the total content being 0.6% to 4.5% by mass in terms of oxides. The thermal conductivity and static modulus of elasticity, which indicates rigidity, of the composite ceramic can be adjusted by adjusting the respective contents of aluminum oxide and zirconium oxide.

[0048] The term "major component" in ceramics refers to a component that accounts for 80% by mass or more of the 100% by mass of the components that make up the ceramic. The components that make up the ceramic can be identified using an X-ray diffractometer (XRD), and their content can be determined by the Rietveld method. Metal elements obtained using an X-ray fluorescence analyzer (XRF) or an ICP (Inductively Coupled Plasma) emission spectrometer may be converted into the identified components.

[0049] The first end portion 3211 may be formed of a ceramic having the same main component as the central portion 31, or a ceramic having a different main component.

[0050] Next, an example of a method for manufacturing the ceramic spacer 3 will be described. For example, when the spacer 3 is formed of ceramic containing zirconium oxide as a main component, first, zirconium oxide powder as the main component, yttrium oxide powder as a stabilizer, a dispersant for dispersing the zirconium oxide powder as needed, and a binder such as polyvinyl alcohol are wet-mixed for 40 to 50 hours using a barrel mill, rotary mill, vibration mill, bead mill, sand mill, agitator mill, or the like to form a slurry.

[0051] Here, the average particle size (D 50) is 0.1 μm or more and 2.2 μm or less, and the content of yttrium oxide powder in the total 100 mass% of the above powders is 3.6 mass% or more and 8.8 mass% or less. Next, a predetermined amount of an organic binder such as paraffin wax, PVA (polyvinyl alcohol), or PEG (polyethylene glycol) is weighed and added to the slurry. A thickening stabilizer, a dispersant, a pH adjuster, an antifoaming agent, etc. may also be added. As a stabilizer, at least one powder of cerium oxide (CeO), dysprosium oxide (DyO), magnesium oxide (MgO), calcium oxide (CaO), etc. may be used instead of yttrium oxide (YO).

[0052] When the spacer 3 is made of ceramics containing cordierite as a main component, first, synthetic cordierite (2MgO.2Al2O3.5SiO2) powder having an average particle size of 0.5 μm to 5 μm, magnesium aluminate (MgAl2O4) powder having an average particle size of 0.5 μm to 3 μm, and an oxide powder of Y, Yb, Er, or Ce having an average particle size of 0.5 μm to 2 μm are prepared. The synthetic cordierite powder and magnesium aluminate powder constitute the main components in this disclosure, and the oxide powder of any one of Y, Yb, Er, and Ce constitutes the secondary component. The synthetic cordierite powder is a powder that is synthesized in advance so that, excluding the amount of magnesium aluminate powder added from 100% by mass of the main component, Mg is in the range of 11.77% by mass or more and 13.3% by mass or less in terms of oxide, Al is in the range of 29.1% by mass or more and 33.8% by mass or less in terms of oxide, and Si is in the range of 52.0% by mass or more and 53.6% by mass or less in terms of oxide.

[0053] Then, predetermined amounts of synthetic cordierite powder and magnesium aluminate powder are weighed out, for example, 93.5% by mass to 99.9% by mass of synthetic cordierite powder and 0.01% by mass to 6.5% by mass of magnesium aluminate powder. Next, the auxiliary components are weighed out so that the range is 4.5% by mass to 15.0% by mass relative to the total of 100% by mass of the synthetic cordierite powder and magnesium aluminate powder, and the mixture is wet-mixed using a ball mill for 5 hours to 30 hours until the average particle size is 2 μm or less to obtain a slurry. The addition of organic binders and the like may be performed as described above.

[0054] Next, a slurry containing zirconium oxide powder or synthetic cordierite powder is spray-dried to obtain granules. These granules are then filled into a mold and molded. The molding process can be performed by pressure molding or injection molding. The molding pressure in the pressure molding is, for example, 78 MPa or more and 128 MPa or less.

[0055] Next, the compact is fired to obtain a ceramic sintered body. Firing is performed, for example, in an air atmosphere. When obtaining ceramics containing zirconium oxide as the main component, the firing temperature is 1400°C or higher and 1500°C or lower. When obtaining ceramics containing cordierite as the main component, the firing temperature is 1340°C or higher and 1440°C or lower. In either case, the holding time may be 1 hour or higher and 4 hours or lower. The ceramic sintered body obtained by firing can be used as a spacer 3 as is. If necessary, the ceramic sintered body may be subjected to at least one of grinding and polishing to form the first contact surface and the second contact surface. This allows for a spacer 3 with high dimensional accuracy.

[0056] In this embodiment, the surface properties of the spacer 3, such as the root-mean-square slope or kurtosis, can be adjusted as desired by appropriately adjusting the surface properties of the mold used for pressure molding or injection molding in the molding process. Specifically, the mold includes a die having a molding space for filling granules, an upper punch that applies pressure to the granules filled in the molding space from above, and a lower punch that applies pressure to the granules from below. To make the average root-mean-square slope RΔq1 of the first contact surface smaller than the average root-mean-square slope RΔq2 of the side surfaces, the average root-mean-square slope of the first pressure surface of the upper punch forming the first contact surface can be made smaller than the average root-mean-square slope of the inner surface of the die. To make the average value RΔq2 0.7 or less, the average root-mean-square slope of the inner surface of the die can be made, for example, 0.88 or less.

[0057] To make the average value Rsk1 of the kurtosis on the first contact surface smaller than the average value Rsk2 of the kurtosis on the side surface, the average value of the kurtosis on the first pressure surface of the upper punch can be made smaller than the average value of the kurtosis on the inner surface of the die. To obtain a spacer in which the difference between the average values ​​RΔq1 and RΔq2 is 0.05 or more, a molding die in which the difference between the average value of the root-mean-square slope of the first pressure surface of the upper punch and the average value of the root-mean-square slope of the inner surface of the die is, for example, 0.063 or more, taking shrinkage into consideration, can be used.

[0058] As a result, the average value RΔq1 of the root mean square slope in the roughness curve of the first contact surface 322 can be made smaller than the average value RΔq2 of the root mean square slope in the roughness curve of the side surface 300. The average value Rsk1 of the kurtosis in the roughness curve of the first contact surface 301 can be made smaller than the average value Rsk2 of the kurtosis in the roughness curve of the side surface 300.

[0059] The relationship between the second contact surface and the side surface can also be determined by adjusting the average root-mean-square slope and average kurtosis of the inner surface of the die and the first pressing surface of the lower punch using the same approach as described above. Both the upper and lower punches have planar second pressing surfaces that connect to the first pressing surface on the outer periphery. The second pressing surfaces form the upper and lower surfaces of the outer edge of the central portion.

[0060] In the molding process of this embodiment, a spacer 3 having a desired shape can be obtained by forming a mold used for pressure molding or injection molding into the desired shape. When pressure molding is performed, the molding pressure is, for example, 98 MPa or more and 294 MPa or more. To make the area occupancy rate of the pores at the first end portion greater than the area occupancy rate of the pores at the outer edge of the central portion, the molding pressure may be, for example, 147 MPa or more and 294 MPa or more.

[0061] In this embodiment, the side surface 300 of the ceramic sintered body obtained by firing is not subjected to processing such as grinding or polishing, so that the side surface 300 of the spacer 3 can be a fired surface.

[0062] Another example of a method for manufacturing the spacer 3 made of the above-described ceramic will now be described. For example, the first end portion 3211, the second end portion 3212, and the central portion 31 are separately manufactured. Next, the obtained first end portion 3211 and second end portion 3212 are joined to the end surface of the central portion 31 by adhesive or the like. In this manner, the first end portion 3211, the second end portion 3212, and the central portion 31 can be made of different materials.

[0063] Next, a method for manufacturing the double-glazed glass 100 will be described. First, the first glass substrate 1 is held so that its surface is horizontal. Next, a plurality of spacers 3 are arranged on the surface of the first glass substrate 1 at predetermined intervals, as shown in FIG. 2A . To do this, for example, the spacers 3 are held by a suction means (not shown) having an air suction port, and the spacers 3 are transported to a predetermined position on the surface of the first glass substrate 1. Next, the suction means is lowered at that position to place the spacers 3 on the surface of the first glass substrate 1, the air suction is stopped in that state, and the suction means is raised. This operation of returning the spacers to their original position in preparation for the next suction can be repeated. The suction and transport of the spacers 3 can be performed row by row, or multiple spacers can be performed at once.

[0064] As another method, for example, a plate (not shown) having a plurality of through holes each large enough to allow only one spacer 3 to pass through is placed on the surface of the first glass substrate 1. Next, a large number of spacers 3 are scattered on the plate, and it is confirmed that the spacers 3 are fitted into all of the through holes. Thereafter, the plate is removed together with any excess spacers 3, thereby allowing a plurality of spacers 3 to be arranged at predetermined intervals on the surface of the first glass substrate 1. After the spacers 3 are arranged on the surface of the first glass substrate 1 as described above, a seal portion 6 is formed around the peripheral edge 5 of the first glass substrate 1.

[0065] Next, the air in the sealed internal space 4 between the pair of glass substrates 1 and 2 is exhausted through the exhaust pipe 7 using, for example, a rotary pump to reduce the pressure. Thereafter, the exhaust port is sealed by bonding a metal cover (not shown) or the like. In this manner, the double-glazed glass 100 is manufactured.

[0066] Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and various modifications and improvements are possible.

[0067] In the above-described embodiment, the spacer 3 is made of a sintered ceramic body. However, the spacer 3 may be made of, for example, metal or resin. Examples of metals include stainless steels such as SUS304 and SUS316, and metals with relatively low thermal conductivity such as titanium or titanium alloys. Examples of resins include polyvinylidene fluoride, polychlorotrifluoroethylene, polytetrafluoroethylene, tetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (ETFE). The spacer 3 may also be a composite of different materials, such as ceramics, metals, or resins. The first end portion 3211 and the central portion 31 may be made of different materials.

[0068] When the spacer 3 is made of metal, a powder metallurgy method can be used to adjust the surface properties of the mold that comes into contact with the powder, thereby obtaining a spacer 3 with the desired surface properties. When the spacer 3 is made of resin, an injection molding method can be used to adjust the surface properties of the mold that comes into contact with the molten resin, thereby obtaining a spacer 3 with the desired surface properties. A spacer 3 that is a composite of different materials can be obtained by separately producing multiple members made of different materials and joining the members together by adhesive or the like.

[0069] REFERENCE SIGNS LIST 1 First glass substrate 2 Second glass substrate 3 Spacer 300 Side surface 301 First contact surface 302 Second contact surface 31 Central portion 3211 First end portion 3212 Second end portion 322 First contact surface 323 Second contact surface 4 Internal space 5 Peripheral edge portion 6 Sealing portion 7 Exhaust pipe 100 Double glazing

Claims

1. A spacer is interposed between a first glass substrate and a second glass substrate facing each other and is arranged in contact with the first glass substrate and the second glass substrate, a first contact surface disposed in contact with the first glass substrate; a second contact surface disposed in contact with the second glass substrate; a side surface located between the first contact surface and the second contact surface; Equipped with The average value RΔq1 of the root mean square slope of the roughness curve of the first contact surface is smaller than the average value RΔq2 of the root mean square slope of the roughness curve of the side surface; Spacer.

2. The spacer according to claim 1 , wherein an average value Rsk1 of kurtosis in the roughness curve of the first contact surface is smaller than an average value Rsk2 of kurtosis in the roughness curve of the side surface.

3. The spacer of claim 1 , wherein the side surface is a sintered surface.

4. The spacer according to claim 1 , wherein the difference between the average value RΔq1 and the average value RΔq2 is 0.05 or more.

5. The spacer according to claim 1 , wherein the average value RΔq2 is 0.7 or less.

6. The insulating film further includes a plate-shaped or columnar central portion, a first end portion protruding from the central portion, and a second end portion located on the opposite side to the first end portion and protruding from the central portion, The side surface is located at an outer edge of the central portion, the first contact surface is located at the first end; the second contact surface is located at the second end; The spacer according to claim 1 , wherein a width perpendicular to a height direction of the first end portion is smaller than a width perpendicular to a height direction of the central portion.

7. The spacer of claim 6 , wherein the first end is spherical.

8. The spacer of claim 6 , wherein the height of the central portion is greater than the sum of the heights of the first end and the second end.

9. The spacer according to claim 6 , wherein an area occupancy rate of the pores at the first end portion is greater than an area occupancy rate of the pores at an outer edge of the central portion.

10. 2. The spacer according to claim 1, which is made of a ceramic sintered body containing zirconium oxide, mullite, forsterite, cordierite, steatite, alkali metal aluminosilicate, aluminum titanate or zinc oxide as a main component.

11. 2. The spacer according to claim 1, which is made of a ceramic sintered body containing a composite compound of aluminum oxide and zirconium oxide.

12. The first glass substrate; The second glass substrate; an internal space located between the first glass substrate and the second glass substrate; A peripheral portion of the first glass substrate; A seal portion that seals the peripheral portion; A spacer according to any one of claims 1 to 11; Equipped with double glazing.

13. The insulating glass according to claim 12, further comprising an exhaust port for evacuating the internal space.