US20040186001A1 - Low transmittance glass - Google Patents
Low transmittance glass Download PDFInfo
- Publication number
- US20040186001A1 US20040186001A1 US10/815,921 US81592104A US2004186001A1 US 20040186001 A1 US20040186001 A1 US 20040186001A1 US 81592104 A US81592104 A US 81592104A US 2004186001 A1 US2004186001 A1 US 2004186001A1
- Authority
- US
- United States
- Prior art keywords
- glass
- low transmittance
- transmittance
- ultraviolet
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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- 239000006062 low-transmittance glass Substances 0.000 title claims abstract description 47
- 239000011521 glass Substances 0.000 claims abstract description 152
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 74
- 238000002834 transmittance Methods 0.000 claims abstract description 63
- FUJCRWPEOMXPAD-UHFFFAOYSA-N Li2O Inorganic materials [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 claims abstract description 54
- XUCJHNOBJLKZNU-UHFFFAOYSA-M dilithium;hydroxide Chemical compound [Li+].[Li+].[OH-] XUCJHNOBJLKZNU-UHFFFAOYSA-M 0.000 claims abstract description 52
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims abstract description 17
- 230000005855 radiation Effects 0.000 claims abstract description 13
- 239000003086 colorant Substances 0.000 claims abstract description 12
- 239000005361 soda-lime glass Substances 0.000 claims abstract description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 37
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 31
- 239000000203 mixture Substances 0.000 claims description 23
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 claims description 21
- 239000000377 silicon dioxide Substances 0.000 claims description 17
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 15
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 claims description 14
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 13
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 13
- 229910052681 coesite Inorganic materials 0.000 claims description 11
- 229910052906 cristobalite Inorganic materials 0.000 claims description 11
- 229910052682 stishovite Inorganic materials 0.000 claims description 11
- 229910052905 tridymite Inorganic materials 0.000 claims description 11
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 10
- 229910052593 corundum Inorganic materials 0.000 claims description 10
- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Chemical compound O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 claims description 10
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 10
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims description 9
- 229910052711 selenium Inorganic materials 0.000 claims description 8
- 239000006121 base glass Substances 0.000 claims description 7
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 claims description 5
- 239000000463 material Substances 0.000 description 29
- 230000002745 absorbent Effects 0.000 description 22
- 239000002250 absorbent Substances 0.000 description 22
- 230000003287 optical effect Effects 0.000 description 19
- 238000007906 compression Methods 0.000 description 17
- 230000006835 compression Effects 0.000 description 17
- 239000011669 selenium Substances 0.000 description 16
- 230000002787 reinforcement Effects 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 12
- 238000010521 absorption reaction Methods 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 230000008018 melting Effects 0.000 description 8
- 238000002844 melting Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 239000003795 chemical substances by application Substances 0.000 description 7
- 230000007423 decrease Effects 0.000 description 7
- 230000005284 excitation Effects 0.000 description 6
- 230000000704 physical effect Effects 0.000 description 6
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 5
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(II) oxide Inorganic materials [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 239000005357 flat glass Substances 0.000 description 5
- 238000007670 refining Methods 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 4
- 239000003638 chemical reducing agent Substances 0.000 description 4
- VQCBHWLJZDBHOS-UHFFFAOYSA-N erbium(III) oxide Inorganic materials O=[Er]O[Er]=O VQCBHWLJZDBHOS-UHFFFAOYSA-N 0.000 description 4
- 230000009477 glass transition Effects 0.000 description 4
- 238000000265 homogenisation Methods 0.000 description 4
- PLDDOISOJJCEMH-UHFFFAOYSA-N neodymium oxide Inorganic materials [O-2].[O-2].[O-2].[Nd+3].[Nd+3] PLDDOISOJJCEMH-UHFFFAOYSA-N 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- GNRSAWUEBMWBQH-UHFFFAOYSA-N nickel(II) oxide Inorganic materials [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- WWNBZGLDODTKEM-UHFFFAOYSA-N sulfanylidenenickel Chemical compound [Ni]=S WWNBZGLDODTKEM-UHFFFAOYSA-N 0.000 description 3
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 150000001342 alkaline earth metals Chemical class 0.000 description 2
- GHPGOEFPKIHBNM-UHFFFAOYSA-N antimony(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Sb+3].[Sb+3] GHPGOEFPKIHBNM-UHFFFAOYSA-N 0.000 description 2
- 230000005587 bubbling Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 229910000420 cerium oxide Inorganic materials 0.000 description 2
- 229910000423 chromium oxide Inorganic materials 0.000 description 2
- 229910000428 cobalt oxide Inorganic materials 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000006066 glass batch Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 229910001947 lithium oxide Inorganic materials 0.000 description 2
- GEYXPJBPASPPLI-UHFFFAOYSA-N manganese(III) oxide Inorganic materials O=[Mn]O[Mn]=O GEYXPJBPASPPLI-UHFFFAOYSA-N 0.000 description 2
- 239000006060 molten glass Substances 0.000 description 2
- 229910000476 molybdenum oxide Inorganic materials 0.000 description 2
- 229910000480 nickel oxide Inorganic materials 0.000 description 2
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 2
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 2
- PQQKPALAQIIWST-UHFFFAOYSA-N oxomolybdenum Chemical compound [Mo]=O PQQKPALAQIIWST-UHFFFAOYSA-N 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- 239000005751 Copper oxide Substances 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000010459 dolomite Substances 0.000 description 1
- 229910000514 dolomite Inorganic materials 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
- C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
- C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
- C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
- C03C3/095—Glass compositions containing silica with 40% to 90% silica, by weight containing rare earths
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C4/00—Compositions for glass with special properties
- C03C4/02—Compositions for glass with special properties for coloured glass
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C4/00—Compositions for glass with special properties
- C03C4/08—Compositions for glass with special properties for glass selectively absorbing radiation of specified wave lengths
- C03C4/082—Compositions for glass with special properties for glass selectively absorbing radiation of specified wave lengths for infrared absorbing glass
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C4/00—Compositions for glass with special properties
- C03C4/08—Compositions for glass with special properties for glass selectively absorbing radiation of specified wave lengths
- C03C4/085—Compositions for glass with special properties for glass selectively absorbing radiation of specified wave lengths for ultraviolet absorbing glass
Definitions
- the present invention relates to a low transmittance glass which has advantages of high heat ray absorptivity, high quality, and high productivity. It particularly relates to a glass having low visible light transmittance which has a smoky color, such as gray to green, and has a high heat ray absorption performance, it more particularly relates to a low transmittance glass which is suitable for a window glass to be reinforced and installed in a vehicle.
- the present invention relates to a green glass which has advantages of high heat ray absorptivity, high ultraviolet absorptivity, high quality, and high productivity. It particularly relates to a glass having high visible light transmittance which has a shade of green, and has a high heat ray absorption performance, and it more particularly relates to a green glass which is suitable for a window glass to be reinforced and installed in a vehicle.
- a variety of glasses with ultraviolet/infrared absorptivity to be used as a vehicle windshield have been proposed with the view of preventing degradation of luxurious interior materials and reducing cooling load of the vehicle.
- a glass having low visible light transmittance is preferably used for a rear window glass of a vehicle.
- the front windshield of a vehicle is obligated to have a visible light transmittance higher than a specific level for enough visibility of a driver.
- a glass having high visible light transmittance and provided with ultraviolet and heat ray absorptivity has a greenish shade because the ends of its ultraviolet absorption range and infrared absorption range overlap the visible range.
- Ultraviolet/infrared absorbent glasses having low to middle visible light transmittance, low ultraviolet transmittance and low total solar radiation transmittance have been disclosed in Japanese patent H10-114540A and H10-45425A. Since these ultraviolet/infrared absorbent glasses have high heat ray absorption characteristics, productivity of each glass in a glass melting furnace is low. Inside the melting furnace, a top of the glass is directly heated with flames, but the bottom of the glass material can not be sufficiently heated because a large part of heat rays directed at the surface of the glass material by the radiation of the flames are absorbed by the top of the glass material. It is thus difficult to melt the glass material in the melting furnace uniformly.
- the glass material is necessarily maintained at a higher-than-normal degree of reduction in order to provide high heat ray absorption characteristics thereto. Therefore, a large amount of reducing agents, mainly including graphite powder, etc., can be added into the glass batch, but such agents are liable to cause unfused silica because the agents can exceedingly react with sulfate, mainly including sodium sulfate, etc., which is added to the glass batch as a refining agent.
- reducing agents mainly including graphite powder, etc.
- At least one of the following processes can be adopted, such as: lowering the amount of the glass material below that for the ordinary operation; heating the bottom of the glass material by energizing electrodes inserted into the bottom of the furnace; and bubbling the glass material.
- the low transmittance glass of the present invention is composed of soda-lime-silica glass comprising 0.001 to 2 wt. % Li 2 O and, as colorant, 0.7 to 2.2 wt. % total iron oxide (T-Fe 2 O 3 ) expressed as Fe 2 O 3 .
- the glass with a thickness between 2.1 mm and 6 mm has visible light transmittance (YA) of not greater than 65%, measured by using the CIE illuminant A, total solar radiation transmittance (TG) of not greater than 60%, and ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 25%.
- the low transmittance glass of the present invention has superior heat ray absorption properties, and it is improved in quality and productivity by including Li 2 O in its base glass composition so as to lower viscosity of the glass material, accelerating melt and homogenization of the glass material, and it also has superior capacity for reinforcement.
- the glass material of the low transmittance glass of the present invention has low viscosity, melt and homogenization of the glass material are accelerated.
- the low transmittance glass is improved in quality and productivity, and is provided with low infrared transmittance.
- the low transmittance glass of the present invention Since when applied with reinforcement by air blast cooling, the low transmittance glass of the present invention obtains higher surface compression than that of conventional ones, it is superior in capacity for reinforcement.
- the low transmittance glass of the present invention has low visible light transmittance and low ultraviolet transmittance, so that it is suitable for a rear view window of a vehicle.
- the ultraviolet/infrared absorbent green glass of the present invention is composed of soda-lime-silica glass comprising 0.001 to 2 wt. % Li 2 O and, as colorant, 0.4 to 2 wt. % total iron oxide (T-Fe 2 O 3 ) expressed as Fe 2 O 3 wherein FeO expressed as Fe 2 O 3 is 15 to 60% of T-Fe 2 O 3 .
- the glass with a thickness between 2.1 mm and 6 mm has visible light transmittance (YA) of not less than 70%, measured by using the CIE illuminant A, and total solar radiation transmittance (TG) of not greater than 60%.
- the ultraviolet/infrared absorbent green glass of the present invention has superior heat ray absorption properties, and it is improved in quality and productivity by including Li 2 O in its base glass composition so as to lower viscosity of the glass material, accelerating melt and homogenization of the glass material, and it also has superior capacity for reinforcement.
- the glass material of the low ultraviolet/infrared absorbent green glass of the present invention has low viscosity, melt and homogenization of the glass material are accelerated.
- the green glass is improved in quality and productivity, and it is provided with low infrared transmittance. Since when applied with reinforcement by air blast cooling, the glass obtains higher surface compression than that of conventional ones, it is superior in capacity for reinforcement.
- the green glass has high visible light transmittance and low ultraviolet transmittance, so that it is suited for a window of a vehicle.
- FIG. 1 is a graph showing a relationship between Li 2 O content and temperature at which log ⁇ becomes 2;
- FIG. 2 is a graph showing a relationship between Li 2 O content and surface compression
- FIG. 3 is a graph showing a relationship between Li 2 O content and transmittance of light having a wavelength of 700 nm.
- a low transmittance glass of the present invention may be composed of a base glass composition comprising:
- the low transmittance glass of the present invention is preferable to include at least one selected from the group consisting of Se, CoO, Cr 2 O 3 , and NiO as colorant.
- the preferable content of Se is 0.0001 to 0.1 wt. %, that of CoO is 0.0001 to 0.1 wt. %, that of Cr 2 O 3 is 0.001 to 2 wt. %, and that of NiO is 0.001 to 2 wt. %.
- the low transmittance glass of the present invention is preferable to include at least one selected from the group consisting of TiO 2 , CeO 2 , MoO 3 , V 2 O 5 and La 2 O 3 as colorant in an amount of 0.0001 to 1 wt %.
- This low transmittance glass of the present invention has visible light transmittance (YA) of 5 to 65%, measured by using CIE illuminant A, total solar radiation transmittance (TG) of not greater than 50%, and ultraviolet transmittance (Tuv) defined by ISO 9050 not greater than 20%, in case that the glass has a thickness between 2.1 mm and 6 mm.
- Li 2 O is a component for lowering viscosity of the glass material and thus improving productivity of the glass. Since Li 2 O has an effect of making thermal expansion coefficient and Young's modulus of the glass larger in case that the content of Li 2 O is in a specific range, Li 2 O is also a component for increasing surface compression of the glass when the glass is applied with reinforcement by air blast cooling, improving a capacity for reinforcement of the glass.
- the content of Li 2 O is set in the 0.001 to 2% range in the present invention. Since Li 2 O material is costly, the content of Li 2 O is preferably taken as less than 2% from a compromise between the cost and the effect of Li 2 O.
- Iron oxide is present in the form of Fe 2 O 3 and the form of FeO in the glass.
- Fe 2 O 3 is a component for improving the ultraviolet absorptivity
- FeO is a component for improving the infrared absorptivity.
- T-Fe 2 O 3 total amount of iron oxide expressed as Fe 2 O 3
- the efficiency of ultraviolet and infrared absorptivity becomes small so as not to provide desired optical properties.
- T-Fe 2 O 3 exceeds 2.2%, the infrared absorptivity of T-Fe 2 O 3 becomes too high to produce the glass in an ordinary melting furnace, and the color unpreferably becomes too greenish.
- T-Fe 2 O 3 long time is required to change the glass composition in the furnace.
- FeO/T-Fe 2 O 3 ratio a weight of FeO expressed as Fe 2 O 3 against T-Fe 2 O 3
- FeO/T-Fe 2 O 3 ratio is more than 50%, silica-rich ream and silica scum are present in a glass because the glass is highly reduced, resulting in decrease of productivity.
- SiO 2 is a main component for forming skeleton of glass. Less than 65% SiO 2 lowers the durability of the glass and more than 80% SiO 2 raises the melting temperature of the glass so high.
- Al 2 O 3 is a component for improving the durability of the glass. More than 5% Al 2 O 3 raises the melting temperature of the glass so high.
- MgO and CaO improve the durability of the glass and adjust a liquidus temperature and viscosity of the glass. More than 10% MgO raises the liquidus temperature. Less than 5% or more than 15% CaO raises the liquidus temperature of the glass. The durability of the glass is lowered when the total amount of MgO and CaO is less than 5%, while the liquidus temperature is increased when the total exceeds 15%.
- Na 2 O and K 2 O prompt the glass to melt.
- the efficiency of promotion of melting becomes poor when Na 2 O is less than 10% or the total of Na 2 O and K 2 O is less than 10%, while the durability of the glass is lowered when Na 2 O exceeds 20% or the total of Na 2 O and K 2 O exceeds 20%.
- K 2 O is preferable not to exceed 5% because of its expensive cost.
- B 2 O 3 is a component for improving the durability of the glass, prompting to melt, and yet enhancing the ultraviolet absorption.
- B 2 O 3 should be less than 5%, since difficulties during molding are caused due to the vaporization of B 2 O 3 when B 2 O 3 exceeds 5%.
- Se, CoO, Cr 2 O 3 and NiO are components for adjusting visible light transmittance and color of the glass, so that it is preferable to add at least one of these components in the glass.
- Se gives a red to pink shade to the glass and also gives grayish shade to the glass by cooperating with FeO or CoO.
- Se When Se is included in the glass, more than 0.1% Se reduces visible light transmittance too much, so that the glass can not be provided with desired properties.
- the preferable content of Se is 0.0001 to 0.1%.
- CoO gives a blue shade to the glass and also gives grayish shade to the glass by cooperating with Se, NiO or Fe 2 O 3 .
- CoO is included in the glass, more than 0.1% CoO reduces visible light transmittance too much, so that the glass can not be provided with desired properties.
- the preferable content of CoO is 0.0001 to 0.1%.
- Cr 2 O 3 gives a green shade to the glass and also adjusts visible light transmittance and color of the glass by cooperating with Se, NiO, CoO or Fe 2 O 3 . More than 2% CrO 3 reduces visible light transmittance too much, so that the glass can not be provided with desired properties.
- the preferable content of Cr 2 O 3 is 0.001 to 2%.
- NiO gives a brown to purple shade to the glass and also gives grayish shade to the glass by cooperating with FeO or CoO. More than 2% NiO reduces visible light transmittance too much, so that the glass can not be provided with desired optical properties, and it unpreferably activates formation of nickel sulfide stones.
- the preferable content of NiO is 0.001 to 2%.
- At least one selected from the group consisting of TiO 2 , CeO 2 , MoO 3 , V 2 O 5 and La 2 O 3 may be added as auxiliary ultraviolet absorbing agent in an amount of 0.0001 to 1%.
- Sulfate of alkaline or alkaline earth metal has been added as a refining agent for the glass, and the glass usually includes SO 3 in an amount of about 0.1 to 0.5%.
- SO 3 in an amount of about 0.1 to 0.5%.
- One or more than two among Sb 2 O 3 , SnO 2 , and the like may be added as a reducing agent or a refining agent for the glass in an amount not greater than 1%.
- ZnO may be added in an amount not greater than 1%.
- the low transmittance glass of the present invention has visible light transmittance (YA) of not greater than 65%, measured by using the CIE illuminant A, total solar radiation transmittance (TG) of not greater than 60%, and ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 25%, when the glass has a thickness in a range of 2.1 to 6 mm.
- YA is preferable to be in a range of 5 to 65%
- TG is preferable not to exceed 50%
- Tuv is preferable not to exceed 20%.
- each glass plate has a thickness between 3.5 mm and 5 mm, so as to obtain the samples.
- Each sample was determined in optical properties including visible light transmittance (YA) measured by using the CIE illuminant A, total solar radiation transmittance (TG), ultraviolet transmittance (Tuv) defined by ISO 9050, dominant wavelength (DW) and excitation purity (Pe) measured by using the CIE illuminant C.
- the samples were also determined in physical properties including glass transition temperature (Tg), deformation temperature (Td), mean thermal expansion coefficient of the 50 to 350° C. range ( ⁇ ( 50-350 )), Young's modulus (E), surface compression and the temperature at which log ⁇ becomes 2.
- Tg glass transition temperature
- Td deformation temperature
- ⁇ ( 50-350 ) mean thermal expansion coefficient of the 50 to 350° C. range
- E Young's modulus
- surface compression the temperature at which log ⁇ becomes 2.
- Each sample was formed into a rod-like shape having a length of 15 mm and a diameter of 5 mm, and then it was loaded with a load of 5 g and heated from the room temperature to 700° C. at a rate of 10° C.
- silica glass rod prepared as a standard sample by the use of EXSTAR 6000 (SEIKO Electronics Inc.), so as to measure glass transition temperature (Tg), deformation temperature (Td) and mean thermal expansion coefficient of the 50 to 350° C. range ( ⁇ ( 50-350 ) .
- Young's modulus (E) was measured with ultrasonic wave according to sing-around method, surface compression was measured with a Babinet-Style surface stress meter according to via-scope method, and the temperature at which log ⁇ becomes 2 was measured according to platinum ball drawing method.
- each glass of the present invention has the temperature at which log ⁇ becomes 2, which is an index of high temperature viscosity, so that the low transmittance glass of the present invention is excellent in meltability.
- Each low transmittance glass of the invention has also high surface compression, so that the low transmittance glass has large capacity for reinforcement.
- Examples 1-10 have preferable optical properties, such as: visible light transmittance (YA) measured by using the CIE illuminant A of 5 to 65%, total solar radiation transmittance (TG) of not greater than 50% and ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 20%. These examples also have dominant wavelength (DW) measured by using the CIE illuminant C of 490 to 560 nm and excitation purity (Pe) measured by using the CIE illuminant C of not greater than 9%.
- YA visible light transmittance
- TG total solar radiation transmittance
- Tiv ultraviolet transmittance
- DW dominant wavelength
- Pe excitation purity
- Comparative Examples 1 and 2 are conventional low transmittance glasses which do not include Li 2 O. These glasses have higher temperature at which log ⁇ becomes 2 and lower surface compression than those of the present invention, resulting in reduction of productivity and capacity for reinforcement.
- the present invention provides a low transmittance glass composition having superior heat ray absorption characteristics and an advantage of high productivity.
- the present invention provides a glass having low visible light transmittance which has smoky color, such as gray to green, and high heat ray absorption characteristics, more particularly, it provides a low transmittance glass which is suited for a window glass to be reinforced and installed in a vehicle.
- the ultraviolet/infrared absorbent green glass of the present invention preferably has the same base glass composition as the low transmittance glass mentioned above.
- the ultraviolet/infrared absorbent green glass of the present invention preferably includes as colorant:
- the ultraviolet/infrared absorbent green glass preferably has ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 35%, dominant wavelength (DW) measured by using the CIE illuminant C of 490 to 560 nm, and excitation purity (Pe) measured by using the CIE illuminant C of less than 6% when the glass has a thickness between 2.1 mm and 6 mm.
- Tuv ultraviolet transmittance
- DW dominant wavelength
- Eu excitation purity
- the ultraviolet/infrared absorbent green glass is preferable to include at least one selected from the group consisting of Se, CoO, Cr 2 O 3 , Mn 2 O 3 , CuO, Nd 2 O 3 , Er 2 O 3 , MoO 3 , V 2 O 5 and La 2 O 3 in an amount of 0.0001 to 0.1 wt. %.
- Iron oxide is present in the form of Fe 2 O 3 and the form of FeO in the glass.
- Fe 2 O 3 is a component for improving the ultraviolet absorptivity and FeO is a component for improving the infrared absorptivity.
- T-Fe 2 O 3 total amount of iron oxide expressed as Fe 2 O 3
- the efficiency of ultraviolet and infrared absorptivity becomes small so as not to provide desired optical properties.
- T-Fe 2 O 3 exceeds 2%, visible light transmittance becomes too low and the color of the glass unpreferably becomes too greenish.
- TiO 2 and CeO 2 also are included in the glass, the content of T-Fe 2 O 3 is preferable not to be greater than 1%.
- FeO/T-Fe 2 O 3 ratio a weight of FeO expressed as Fe 2 O 3 against T-Fe 2 O 3 . If FeO/T-Fe 2 O 3 ratio is more than 60%, silica-rich ream and silica scum are present in a glass because the glass is highly reduced, unpreferably resulting in decrease of productivity and lapse of the effect of Li 2 O.
- the FeO/T-Fe 2 O 3 ratio is preferable not to be greater than 50%, more preferable not to be greater than 35%.
- TiO 2 is a component for improving the ultraviolet absorptivity particularly by interaction with FeO.
- the content of TiO 2 is preferable not to be greater than 1%. More than 1% TiO 2 unpreferably raises cost and makes the shade of the glass yellowish. When the effect of absorbing ultraviolet of TiO 2 is expected, TiO 2 is preferably added in an amount of 0.01% or more.
- CeO 2 is a component for improving the ultraviolet absorptivity and is present in the form of Ce 3+ or in the form of Ce 4+ in the glass. Particularly, Ce 3+ is effective in absorbing ultraviolet with less absorptivity in the visible range.
- the content of CeO 2 is preferable not to be greater than 2%. More than 2% CeO 2 unpreferably raises cost and reduces visible light transmittance. When the effect of absorbing ultraviolet of CeO 2 is expected, CeO 2 is preferably added in an amount of 0.01% or more.
- At least one selected from the group consisting of Se, CoO, Cr 2 O 3 , Mn 2 O 3 , CuO, Nd 2 O 3 and Er 2 O 3 as colorant and the group consisting of MoO 3 , V 2 O 5 and La 2 O 3 as auxiliary ultraviolet absorbing agent may be added in an amount of 0.0001 to 1%.
- Sulfate of alkaline or alkaline earth metal has been added as a refining agent for the glass, and the glass usually includes SO 3 in an amount of about 0.1 to 0.5%.
- SO 3 in an amount of about 0.1 to 0.5%.
- One or more than two among Sb 2 O 3 , SnO 2 , and the like may be added as a reducing agent or a refining agent for the glass in an amount not greater than 1%.
- ZnO may be added in an amount not greater than 1%.
- the ultraviolet/infrared absorbent green glass of the present invention is preferable to have visible light transmittance (YA) of not less than 70%, measured by using the CIE illuminant A, and total solar radiation transmittance (TG) of not greater than 60% when the glass has a thickness between 2.1 mm and 6 mm.
- YA visible light transmittance
- TG total solar radiation transmittance
- the ultraviolet/infrared absorbent green glass of the present invention has ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 35%, dominant wavelength (DW) measured by using the CIE illuminant C of 490 to 560 nm, and excitation purity (Pe) measured by using the CIE illuminant C of less than 6%.
- Tiv ultraviolet transmittance
- DW dominant wavelength
- Pe excitation purity
- the glass material thus prepared was held in an electric furnace at 1500° C. for 4 hours.
- the molten glass was cast on a stainless plate, and then annealed to the room temperature so as to obtain 6 mm thick glass plates.
- each glass plate has a thickness between 2.6 mm and 5 mm, so as to obtain the samples.
- Each sample was determined in optical properties including visible light transmittance (YA) measured by using the CIE illuminant A, total solar radiation transmittance (TG), ultraviolet transmittance (Tuv) defined by ISO 9050, dominant wavelength (DW) and excitation purity (Pe) measured by using the CIE illuminant C.
- the samples were also determined in physical properties including glass transition temperature (Tg), deformation temperature (Td), mean thermal expansion coefficient of the 50 to 350° C. range (( ⁇ (50-350) ), Young's modulus (E) , surface compression and the temperature at which log ⁇ becomes 2.
- Tg glass transition temperature
- Td deformation temperature
- E Young's modulus
- silica glass rod prepared as a standard sample by the use of EXSTAR 6000 (SEIKO Electronics Inc.), so as to measure glass transition temperature (Tg), deformation temperature (Td) and mean thermal expansion coefficient of the 50 to 350° C. range ( ⁇ (50-350) ).
- Young's modulus (E) was measured with ultrasonic wave according to sing-around method, surface compression was measured with a Babinet-Style surface stress meter according to via-scope method, and the temperature at which log ⁇ becomes 2 was measured according to platinum ball drawing method.
- Example 18 Example 19
- Example 20 glass composition SiO 2 68.3 67.9 70.0 69.0 69.5 [wt. %] Al 2 O 3 2.87 2.85 1.70 2.40 1.90 MgO 1.65 1.64 2.70 1.70 1.70 CaO 9.23 9.16 8.04 9.11 9.00 Na 2 O 14.5 14.7 13.5 13.4 14.1 K 2 O 0.92 0.92 0.75 0.75 0.80 Li 2 O 0.50 0.33 1.50 2.00 1.00 T-Fe 2 O 3 0.64 0.78 0.80 0.88 0.80 FeO/T-Fe 2 O 3 0.18 0.27 0.26 0.24 0.24 TiO 2 0.16 0.29 0.06 0.10 0.06 CeO 2 1.17 1.44 0.65 0.60 0.87 optical thickness[mm] 3.1 2.6 2.6 2.6 properties YA[%] 77.2 75.0 75.7 74.9 76.5 TG[%] 50.1 47.0 47.6 43.9 49.6 Tuv[%] 15.3 12.7 15.6 11.8 15.0 DW[nm]
- each glass of the present invention has the temperature at which log ⁇ becomes 2, which is an index of high temperature viscosity, so that the ultraviolet/infrared absorbent green glass of the present invention is excellent in meltability.
- Each ultraviolet/infrared absorbent green glass of the invention has also high surface compression, so that the ultraviolet/infrared absorbent green glass has large capacity for reinforcement.
- Examples 11-21 have preferable optical properties, such as: ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 35%, dominant wavelength (DW) measured by using the CIE illuminant C of 490 to 560 nm and excitation purity (Pe) measured by using the CIE illuminant C of smaller than 6% when each glass has a thickness between 2.1 mm to 6 mm.
- ultraviolet transmittance Tuv
- DW dominant wavelength
- Eu excitation purity
- Examples 13-22 have more preferable optical properties to Examples 11 and 12 because ultraviolet transmittance (Tuv) of Examples 13-22 is lower than that of Examples 11 and 12.
- Comparative Examples 3 and 4 are conventional ultraviolet/infrared absorbent glasses which do not include Li 2 O. These glasses have higher temperature at which log ⁇ becomes 2 and lower surface compression than those of the present invention, resulting in reduction of productivity and capacity for reinforcement.
- the present invention makes it possible to produce an ultraviolet/infrared absorbent glass having high visible light transmittance and greenish shade at lower cost than that of conventional ones, because the present invention reduces viscosity of the glass at high temperature.
- the ultraviolet/infrared absorbent green glass of the present invention exhibits superior capacity for reinforcement, so that it is especially fitted for a window glass of a vehicle.
Abstract
Low transmittance glass is composed of soda-lime-silica glass including 0.001 to 2 wt. % Li2O and, as colorant, 0.7 to 2.2 wt. % total iron oxide expressed as Fe2O3 (T-Fe2O3) . The glass has visible light transmittance (YA) of not greater than 65%, measured by using the CIE illuminant A, total solar radiation transmittance (TG) of not greater than 60%, and ultraviolet transmittance defined by ISO 9050 of not greater than 25%, when the glass has a thickness between 2.1 mm and 6 mm.
Description
- This is a divisional application of a patent application Ser. No. 10/166,064 filed on Jun. 11, 2002.
- The present invention relates to a low transmittance glass which has advantages of high heat ray absorptivity, high quality, and high productivity. It particularly relates to a glass having low visible light transmittance which has a smoky color, such as gray to green, and has a high heat ray absorption performance, it more particularly relates to a low transmittance glass which is suitable for a window glass to be reinforced and installed in a vehicle.
- The present invention relates to a green glass which has advantages of high heat ray absorptivity, high ultraviolet absorptivity, high quality, and high productivity. It particularly relates to a glass having high visible light transmittance which has a shade of green, and has a high heat ray absorption performance, and it more particularly relates to a green glass which is suitable for a window glass to be reinforced and installed in a vehicle.
- A variety of glasses with ultraviolet/infrared absorptivity to be used as a vehicle windshield have been proposed with the view of preventing degradation of luxurious interior materials and reducing cooling load of the vehicle. In view of comfort of passengers and privacy protection, a glass having low visible light transmittance is preferably used for a rear window glass of a vehicle.
- The front windshield of a vehicle is obligated to have a visible light transmittance higher than a specific level for enough visibility of a driver. A glass having high visible light transmittance and provided with ultraviolet and heat ray absorptivity has a greenish shade because the ends of its ultraviolet absorption range and infrared absorption range overlap the visible range.
- Ultraviolet/infrared absorbent glasses having low to middle visible light transmittance, low ultraviolet transmittance and low total solar radiation transmittance have been disclosed in Japanese patent H10-114540A and H10-45425A. Since these ultraviolet/infrared absorbent glasses have high heat ray absorption characteristics, productivity of each glass in a glass melting furnace is low. Inside the melting furnace, a top of the glass is directly heated with flames, but the bottom of the glass material can not be sufficiently heated because a large part of heat rays directed at the surface of the glass material by the radiation of the flames are absorbed by the top of the glass material. It is thus difficult to melt the glass material in the melting furnace uniformly.
- The glass material is necessarily maintained at a higher-than-normal degree of reduction in order to provide high heat ray absorption characteristics thereto. Therefore, a large amount of reducing agents, mainly including graphite powder, etc., can be added into the glass batch, but such agents are liable to cause unfused silica because the agents can exceedingly react with sulfate, mainly including sodium sulfate, etc., which is added to the glass batch as a refining agent.
- In order to melt the glass material uniformly, at least one of the following processes can be adopted, such as: lowering the amount of the glass material below that for the ordinary operation; heating the bottom of the glass material by energizing electrodes inserted into the bottom of the furnace; and bubbling the glass material.
- However, lowering the amount of the glass material below that for the ordinary operation causes decrease of the production capacity, thereby raising the production cost. Electrical heating by insertion of electrodes in the bottom of the furnace and bubbling the glass material require modification of the facilities. These processes can cause defects, such as: generation of a lot of defects such as bubbles in the glass depending upon the operating conditions, and result in significant decline of the production capacity.
- The low transmittance glass of the present invention is composed of soda-lime-silica glass comprising 0.001 to 2 wt. % Li2O and, as colorant, 0.7 to 2.2 wt. % total iron oxide (T-Fe2O3) expressed as Fe2O3. The glass with a thickness between 2.1 mm and 6 mm has visible light transmittance (YA) of not greater than 65%, measured by using the CIE illuminant A, total solar radiation transmittance (TG) of not greater than 60%, and ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 25%.
- The low transmittance glass of the present invention has superior heat ray absorption properties, and it is improved in quality and productivity by including Li2O in its base glass composition so as to lower viscosity of the glass material, accelerating melt and homogenization of the glass material, and it also has superior capacity for reinforcement.
- Since the glass material of the low transmittance glass of the present invention has low viscosity, melt and homogenization of the glass material are accelerated. The low transmittance glass is improved in quality and productivity, and is provided with low infrared transmittance.
- Since when applied with reinforcement by air blast cooling, the low transmittance glass of the present invention obtains higher surface compression than that of conventional ones, it is superior in capacity for reinforcement. The low transmittance glass of the present invention has low visible light transmittance and low ultraviolet transmittance, so that it is suitable for a rear view window of a vehicle.
- The ultraviolet/infrared absorbent green glass of the present invention is composed of soda-lime-silica glass comprising 0.001 to 2 wt. % Li2O and, as colorant, 0.4 to 2 wt. % total iron oxide (T-Fe2O3) expressed as Fe2O3 wherein FeO expressed as Fe2O3 is 15 to 60% of T-Fe2O3. The glass with a thickness between 2.1 mm and 6 mm has visible light transmittance (YA) of not less than 70%, measured by using the CIE illuminant A, and total solar radiation transmittance (TG) of not greater than 60%.
- The ultraviolet/infrared absorbent green glass of the present invention has superior heat ray absorption properties, and it is improved in quality and productivity by including Li2O in its base glass composition so as to lower viscosity of the glass material, accelerating melt and homogenization of the glass material, and it also has superior capacity for reinforcement.
- Since the glass material of the low ultraviolet/infrared absorbent green glass of the present invention has low viscosity, melt and homogenization of the glass material are accelerated. The green glass is improved in quality and productivity, and it is provided with low infrared transmittance. Since when applied with reinforcement by air blast cooling, the glass obtains higher surface compression than that of conventional ones, it is superior in capacity for reinforcement. The green glass has high visible light transmittance and low ultraviolet transmittance, so that it is suited for a window of a vehicle.
- FIG. 1 is a graph showing a relationship between Li2O content and temperature at which log η becomes 2;
- FIG. 2 is a graph showing a relationship between Li2O content and surface compression; and
- FIG. 3 is a graph showing a relationship between Li2O content and transmittance of light having a wavelength of 700 nm.
- [Low Transmittance Glass]
- A low transmittance glass of the present invention may be composed of a base glass composition comprising:
- 65 to 80 wt. % SiO2;
- 0 to 5 wt. % Al2O3;
- 0 to 10 wt. % MgO;
- 5 to 15 wt. % CaO wherein a total amount of MgO and CaO is 5 to 15 wt. %; 10 to 20 wt. % Na2O;
- 0 to 5 wt. % K2O wherein a total amount of Na2O and K2O is 10 to 20 wt. %; and
- 0 to 5 wt. % B2O3.
- The low transmittance glass of the present invention is preferable to include at least one selected from the group consisting of Se, CoO, Cr2O3, and NiO as colorant. The preferable content of Se is 0.0001 to 0.1 wt. %, that of CoO is 0.0001 to 0.1 wt. %, that of Cr2O3 is 0.001 to 2 wt. %, and that of NiO is 0.001 to 2 wt. %.
- The low transmittance glass of the present invention is preferable to include at least one selected from the group consisting of TiO2, CeO2, MoO3, V2O5 and La2O3 as colorant in an amount of 0.0001 to 1 wt %.
- This low transmittance glass of the present invention has visible light transmittance (YA) of 5 to 65%, measured by using CIE illuminant A, total solar radiation transmittance (TG) of not greater than 50%, and ultraviolet transmittance (Tuv) defined by ISO 9050 not greater than 20%, in case that the glass has a thickness between 2.1 mm and 6 mm.
- The description will be made as regard to the low transmittance glass composition of the present invention. It should be noted that content of each component will be represented with percentage by weight.
- Li2O is a component for lowering viscosity of the glass material and thus improving productivity of the glass. Since Li2O has an effect of making thermal expansion coefficient and Young's modulus of the glass larger in case that the content of Li2O is in a specific range, Li2O is also a component for increasing surface compression of the glass when the glass is applied with reinforcement by air blast cooling, improving a capacity for reinforcement of the glass.
- When the content of Li2O is not greater than 2%, viscosity of the glass material becomes lowered as the content of Li2O increases, and thus productivity of the glass becomes improved. However, when the content of Li2O is greater than 2%, the effect of lowering viscosity decreases even though the content of Li2O increases. When the content of Li2O is less than 0.001%, Li2O does not sufficiently give its effect of lowering viscosity to the glass material. The relationship between the content of Li2O and the temperature at which log η becomes 2 in a typical soda-lime-silica glass is shown in FIG. 1. It is noted that the temperature at which log η becomes 2 decreases monotonously as the content of Li2O increases, and the slope becomes gentle as the content of Li2O exceeds 2%. Therefore, the content of Li2O is set in the 0.001 to 2% range in the present invention. Since Li2O material is costly, the content of Li2O is preferably taken as less than 2% from a compromise between the cost and the effect of Li2O.
- When the content of Li2O is not greater than 0.5%, surface compression of the glass reinforced with air blast cooling increases as the content of Li2O increases. When the content of Li2O is more than 0.5%, surface compression of the glass is approximately constant even though the content of Li2O increases. The relationship between the content of Li2O and the surface compression in a typical soda-lime-silica glass is shown in FIG. 2. It is noted that although the surface compression increases as the content of Li2O increases, it becomes approximately constant as the content of Li2O exceeds 0.5%. The content of Li2O is preferably taken as 0.5% or less from a compromise between the cost and the effect of Li2O. When the increase of surface compression of the glass by addition of Li2O is expected, Li2O is preferably added in an amount of 0.05% or more.
- Iron oxide is present in the form of Fe2O3 and the form of FeO in the glass. Fe2O3 is a component for improving the ultraviolet absorptivity and FeO is a component for improving the infrared absorptivity. When the total amount of iron oxide (T-Fe2O3) expressed as Fe2O3 is less than 0.7%, the efficiency of ultraviolet and infrared absorptivity becomes small so as not to provide desired optical properties. On the other hand, when T-Fe2O3 exceeds 2.2%, the infrared absorptivity of T-Fe2O3 becomes too high to produce the glass in an ordinary melting furnace, and the color unpreferably becomes too greenish. In case of successively producing glasses by a glass melting furnace with a large amount of T-Fe2O3, long time is required to change the glass composition in the furnace.
- In the present invention, an effect of shifting the light absorption peak of FeO toward the short wavelength range of light is given by coexistence of FeO and Li2O in the soda lime glass. In order to illustrate this effect, the relationship between the content of Li2O and the transmittance of light having a wavelength of 700 nm is shown in FIG. 3. It is noted that the transmittance of light having a wavelength of 700 nm decreases according as the content of Li2O increases. Addition of Li2O makes it possible to lower visible light transmittance effectively with a small content of FeO.
- When the FeO/T-Fe2O3 ratio (a weight of FeO expressed as Fe2O3 against T-Fe2O3) is less than 20%, sufficient heat ray absorptivity can not be obtained. When FeO/T-Fe2O3 ratio is more than 50%, silica-rich ream and silica scum are present in a glass because the glass is highly reduced, resulting in decrease of productivity.
- SiO2 is a main component for forming skeleton of glass. Less than 65% SiO2 lowers the durability of the glass and more than 80% SiO2 raises the melting temperature of the glass so high.
- Al2O3 is a component for improving the durability of the glass. More than 5% Al2O3 raises the melting temperature of the glass so high.
- MgO and CaO improve the durability of the glass and adjust a liquidus temperature and viscosity of the glass. More than 10% MgO raises the liquidus temperature. Less than 5% or more than 15% CaO raises the liquidus temperature of the glass. The durability of the glass is lowered when the total amount of MgO and CaO is less than 5%, while the liquidus temperature is increased when the total exceeds 15%.
- Na2O and K2O prompt the glass to melt. The efficiency of promotion of melting becomes poor when Na2O is less than 10% or the total of Na2O and K2O is less than 10%, while the durability of the glass is lowered when Na2O exceeds 20% or the total of Na2O and K2O exceeds 20%. K2O is preferable not to exceed 5% because of its expensive cost.
- B2O3 is a component for improving the durability of the glass, prompting to melt, and yet enhancing the ultraviolet absorption. B2O3 should be less than 5%, since difficulties during molding are caused due to the vaporization of B2O3 when B2O3 exceeds 5%.
- Se, CoO, Cr2O3 and NiO are components for adjusting visible light transmittance and color of the glass, so that it is preferable to add at least one of these components in the glass.
- Se gives a red to pink shade to the glass and also gives grayish shade to the glass by cooperating with FeO or CoO. When Se is included in the glass, more than 0.1% Se reduces visible light transmittance too much, so that the glass can not be provided with desired properties. The preferable content of Se is 0.0001 to 0.1%.
- CoO gives a blue shade to the glass and also gives grayish shade to the glass by cooperating with Se, NiO or Fe2O3. When CoO is included in the glass, more than 0.1% CoO reduces visible light transmittance too much, so that the glass can not be provided with desired properties. The preferable content of CoO is 0.0001 to 0.1%.
- Cr2O3 gives a green shade to the glass and also adjusts visible light transmittance and color of the glass by cooperating with Se, NiO, CoO or Fe2O3. More than 2% CrO3 reduces visible light transmittance too much, so that the glass can not be provided with desired properties. The preferable content of Cr2O3 is 0.001 to 2%.
- NiO gives a brown to purple shade to the glass and also gives grayish shade to the glass by cooperating with FeO or CoO. More than 2% NiO reduces visible light transmittance too much, so that the glass can not be provided with desired optical properties, and it unpreferably activates formation of nickel sulfide stones. The preferable content of NiO is 0.001 to 2%.
- In order to obtain more desirable shade and properties, at least one selected from the group consisting of TiO2, CeO2, MoO3, V2O5 and La2O3 may be added as auxiliary ultraviolet absorbing agent in an amount of 0.0001 to 1%.
- Sulfate of alkaline or alkaline earth metal has been added as a refining agent for the glass, and the glass usually includes SO3 in an amount of about 0.1 to 0.5%. One or more than two among Sb2O3, SnO2, and the like may be added as a reducing agent or a refining agent for the glass in an amount not greater than 1%. In order further securely to prevent the formation of nickel sulfide stones, ZnO may be added in an amount not greater than 1%.
- The low transmittance glass of the present invention has visible light transmittance (YA) of not greater than 65%, measured by using the CIE illuminant A, total solar radiation transmittance (TG) of not greater than 60%, and ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 25%, when the glass has a thickness in a range of 2.1 to 6 mm. YA is preferable to be in a range of 5 to 65%, TG is preferable not to exceed 50%, and Tuv is preferable not to exceed 20%.
- Hereinafter, examples and comparative examples of the low transmittance glass of the present invention will be described.
- The formulation of typical soda-lime-silica glass material is shown in Table 1. Lithium oxide, ferric oxide, metallic selenium, cobalt oxide, chromium oxide, nickel oxide, titanium oxide, cerium oxide, molybdenum oxide, vanadium pentoxide and lanthanum oxide were added to the glass material as desired. The glass material thus prepared was held in an electric furnace at 1500° C. for 4 hours. The molten glass was cast on a stainless plate and held at 650° C. for 1 hour, and then annealed to the room temperature in the furnace so as to obtain 6 mm thick glass plates.
TABLE 1 component content [g] silica sand 973.6 dolomite 255.7 limestone 30.24 soda ash 230.02 salt cake 9.881 carbon 0.617 total 1500 - The obtained glass plates were polished, so that each glass plate has a thickness between 3.5 mm and 5 mm, so as to obtain the samples. Each sample was determined in optical properties including visible light transmittance (YA) measured by using the CIE illuminant A, total solar radiation transmittance (TG), ultraviolet transmittance (Tuv) defined by ISO 9050, dominant wavelength (DW) and excitation purity (Pe) measured by using the CIE illuminant C.
- The samples were also determined in physical properties including glass transition temperature (Tg), deformation temperature (Td), mean thermal expansion coefficient of the 50 to 350° C. range (α(50-350)), Young's modulus (E), surface compression and the temperature at which log η becomes 2. Each sample was formed into a rod-like shape having a length of 15 mm and a diameter of 5 mm, and then it was loaded with a load of 5 g and heated from the room temperature to 700° C. at a rate of 10° C. per minutes with silica glass rod prepared as a standard sample by the use of EXSTAR 6000 (SEIKO Electronics Inc.), so as to measure glass transition temperature (Tg), deformation temperature (Td) and mean thermal expansion coefficient of the 50 to 350° C. range (α(50-350) . Young's modulus (E) was measured with ultrasonic wave according to sing-around method, surface compression was measured with a Babinet-Style surface stress meter according to via-scope method, and the temperature at which log η becomes 2 was measured according to platinum ball drawing method.
- The base glass composition, the content of colorant, FeO/T-Fe2O3 ratio, the optical properties and the physical properties of each sample were shown in Tables 2 and 3. The contents of the components in these tables are indicated as percentage by weight.
TABLE 2 Example 1 Example 2 Example 3 Example 4 Example 5 glass composition SiO2 71.0 71.5 70.7 71.4 71.2 [wt. %] Al2O3 1.40 0.11 0.89 1.35 1.35 MgO 3.64 3.75 4.13 3.68 3.68 CaO 7.66 8.62 8.38 7.75 7.74 Na2O 13.7 13.6 13.2 13.7 13.6 K2O 0.91 0.07 0.23 0.77 0.76 Li2O 1.00 2.00 0.50 0.05 0.12 T-Fe2O3 1.25 1.40 1.42 1.30 1.30 FeO/T-Fe2O3 0.23 0.24 0.22 0.23 0.23 NiO 0.065 — — 0.016 0.098 CoO 0.019 0.022 0.012 0.004 0.020 Se 0.001 0.003 0.0005 — — Cr2O3 — — 0.002 — — TiO2 0.02 0.03 0.03 0.03 0.03 optical thickness[mm] 5 4 4 4 4 properties YA[%] 17.2 16.3 37.8 48.6 16.9 TG[%] 17.0 13.7 27.5 27.0 15.4 Tuv[%] 9.0 2.4 4.7 8.7 8.2 DW[nm] 556 522 494 502 521 Pe[%] 9.0 1.0 5.8 5.0 4.5 physical Tg [° C.] 531.6 499.1 531.9 547.1 544.8 properties Td [° C.] 603.2 557.7 602.7 625.4 623.7 α(50-350) × e−7 93.4 92.6 95.8 90.0 94.4 E[GPa] 76.2 77.3 74.3 74.0 75.0 surface compressive 112.0 112.8 112.0 109.0 111.3 stress[MPa] temperature at which 1397 1387 1419 1430 1431 log η becomes 2 [° C.] -
TABLE 3 Example 6 Example 7 Example 8 Example 9 Example 10 glass composition SiO2 71.4 71.2 71.6 72.0 71.6 [wt. %] Al2O3 1.35 1.35 1.35 1.35 1.34 MgO 3.69 3.68 3.70 3.72 3.70 CaO 7.76 7.74 7.78 7.83 7.78 Na2O 13.3 13.3 12.4 11.4 11.3 K2O 0.77 0.76 0.77 0.77 0.77 Li2O 0.33 0.33 1.01 1.50 2.00 T-Fe2O3 1.30 1.30 1.31 1.31 1.31 FeO/T-Fe2O3 0.24 0.22 0.22 0.22 0.22 NiO 0.016 0.098 0.098 0.099 0.099 CoO 0.004 0.020 0.020 0.020 0.020 Se — — — — — Cr2O3 — — — — — TiO2 0.03 0.03 0.03 0.03 0.03 optical thickness[mm] 4 3.5 3.5 3.5 3.5 properties YA[%] 49.8 20.8 20.7 20.6 20.6 TG[%] 27.9 19.3 19.1 19.1 19.0 Tuv[%] 9.8 10.3 10.1 9.8 9.8 DW[nm] 502 525 524 523 524 Pe[%] 5.0 4.3 4.3 4.4 4.2 physical Tg [° C.] 535.5 539.2 518.6 510.2 504.7 properties Td [° C.] 612.2 615.4 596.8 598.1 586.2 α(50-350) × e−7 95.1 96.5 91.2 90.2 93.8 E[GPa] 74.9 75.0 76.3 77.5 78.5 surface compressive 112.1 114.3 109 110 117 stress[MPa] temperature at which 1417 1429 1429 1396 1390 log η becomes 2 [° C.] - It is apparent from Tables 2, 3 that each glass of the present invention has the temperature at which log η becomes 2, which is an index of high temperature viscosity, so that the low transmittance glass of the present invention is excellent in meltability. Each low transmittance glass of the invention has also high surface compression, so that the low transmittance glass has large capacity for reinforcement.
- Examples 1-10 have preferable optical properties, such as: visible light transmittance (YA) measured by using the CIE illuminant A of 5 to 65%, total solar radiation transmittance (TG) of not greater than 50% and ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 20%. These examples also have dominant wavelength (DW) measured by using the CIE illuminant C of 490 to 560 nm and excitation purity (Pe) measured by using the CIE illuminant C of not greater than 9%.
- The glass composition, the optical properties and the physical properties of Comparative Examples 1 and 2 each of which was prepared in the same way as Examples 1-10 except for the glass composition are shown in Table 4.
TABLE 4 Comparative Comparative Example 1 Example 2 glass SiO2 70.5 70.6 composition Al2O3 1.66 1.66 [wt. %] MgO 3.72 3.70 CaO 7.96 7.86 Na2O 13.9 13.7 K2O 0.79 0.81 Li2O 0.00 0.00 T-Fe2O3 1.26 1.29 FeO/T-Fe2O3 0.27 0.23 NiO 0.016 0.064 CoO 0.005 0.018 Se — — Cr2O3 — — TiO2 0.03 0.03 optical thickness[mm] 5.0 4.0 properties YA[%] 39.9 23.3 TG[%] 21.7 18.7 Tuv[%] 5.8 8.1 DW[nm] 502 496 Pe[%] 5.9 7.1 physical Tg [° C.] 558.5 557.3 properties Td [° C.] 643.5 642.3 α(50-350) × e−7 92.6 92.6 E[GPa] 74.2 74.2 surface compressive stress 106.0 107.3 [MPa] temperature at which log 1436 1434 η becomes 2 [° C.] - Comparative Examples 1 and 2 are conventional low transmittance glasses which do not include Li2O. These glasses have higher temperature at which log η becomes 2 and lower surface compression than those of the present invention, resulting in reduction of productivity and capacity for reinforcement.
- As described above, the present invention provides a low transmittance glass composition having superior heat ray absorption characteristics and an advantage of high productivity. Particularly, the present invention provides a glass having low visible light transmittance which has smoky color, such as gray to green, and high heat ray absorption characteristics, more particularly, it provides a low transmittance glass which is suited for a window glass to be reinforced and installed in a vehicle.
- [Ultraviolet/Infrared Absorbent Green Glass]
- The ultraviolet/infrared absorbent green glass of the present invention preferably has the same base glass composition as the low transmittance glass mentioned above.
- The ultraviolet/infrared absorbent green glass of the present invention preferably includes as colorant:
- 0.4 to 1 wt. % total iron oxide expressed as Fe2O3 (T-Fe2O3);
- 0 to 1 wt. % TiO2; and
- 0 to 2 wt. % CeO2.
- The ultraviolet/infrared absorbent green glass preferably has ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 35%, dominant wavelength (DW) measured by using the CIE illuminant C of 490 to 560 nm, and excitation purity (Pe) measured by using the CIE illuminant C of less than 6% when the glass has a thickness between 2.1 mm and 6 mm.
- The ultraviolet/infrared absorbent green glass is preferable to include at least one selected from the group consisting of Se, CoO, Cr2O3, Mn2O3, CuO, Nd2O3, Er2O3, MoO3, V2O5 and La2O3 in an amount of 0.0001 to 0.1 wt. %.
- The description will be made as regard to the ultraviolet/infrared absorbent green glass composition of the present invention. It should be noted that content of each component will be represented with percentage by weight.
- The description of the reason why the above base glass composition is desirable for the low transmittance glass applies equally to that for the ultraviolet/infrared absorbent green glass.
- The description will be made as regard to the colorant of the ultraviolet/infrared absorbent green glass of the present invention.
- Iron oxide is present in the form of Fe2O3 and the form of FeO in the glass. Fe2O3 is a component for improving the ultraviolet absorptivity and FeO is a component for improving the infrared absorptivity. When the total amount of iron oxide (T-Fe2O3) expressed as Fe2O3 is less than 0.4%, the efficiency of ultraviolet and infrared absorptivity becomes small so as not to provide desired optical properties. On the other hand, when T-Fe2O3 exceeds 2%, visible light transmittance becomes too low and the color of the glass unpreferably becomes too greenish. When TiO2 and CeO2 also are included in the glass, the content of T-Fe2O3 is preferable not to be greater than 1%.
- When the FeO/T-Fe2O3 ratio (a weight of FeO expressed as Fe2O3 against T-Fe2O3) is less than 15%, sufficient heat ray absorptivity can not be obtained. If FeO/T-Fe2O3 ratio is more than 60%, silica-rich ream and silica scum are present in a glass because the glass is highly reduced, unpreferably resulting in decrease of productivity and lapse of the effect of Li2O. The FeO/T-Fe2O3 ratio is preferable not to be greater than 50%, more preferable not to be greater than 35%.
- TiO2 is a component for improving the ultraviolet absorptivity particularly by interaction with FeO. The content of TiO2 is preferable not to be greater than 1%. More than 1% TiO2 unpreferably raises cost and makes the shade of the glass yellowish. When the effect of absorbing ultraviolet of TiO2 is expected, TiO2 is preferably added in an amount of 0.01% or more.
- CeO2 is a component for improving the ultraviolet absorptivity and is present in the form of Ce3+ or in the form of Ce4+ in the glass. Particularly, Ce3+ is effective in absorbing ultraviolet with less absorptivity in the visible range. The content of CeO2 is preferable not to be greater than 2%. More than 2% CeO2 unpreferably raises cost and reduces visible light transmittance. When the effect of absorbing ultraviolet of CeO2 is expected, CeO2 is preferably added in an amount of 0.01% or more.
- In order to obtain more desirable shade and optical properties, at least one selected from the group consisting of Se, CoO, Cr2O3, Mn2O3, CuO, Nd2O3 and Er2O3 as colorant and the group consisting of MoO3, V2O5 and La2O3 as auxiliary ultraviolet absorbing agent may be added in an amount of 0.0001 to 1%.
- Sulfate of alkaline or alkaline earth metal has been added as a refining agent for the glass, and the glass usually includes SO3 in an amount of about 0.1 to 0.5%. One or more than two among Sb2O3, SnO2, and the like may be added as a reducing agent or a refining agent for the glass in an amount not greater than 1%. In order further securely to prevent the formation of nickel sulfide stones, ZnO may be added in an amount not greater than 1%.
- The ultraviolet/infrared absorbent green glass of the present invention is preferable to have visible light transmittance (YA) of not less than 70%, measured by using the CIE illuminant A, and total solar radiation transmittance (TG) of not greater than 60% when the glass has a thickness between 2.1 mm and 6 mm.
- The ultraviolet/infrared absorbent green glass of the present invention has ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 35%, dominant wavelength (DW) measured by using the CIE illuminant C of 490 to 560 nm, and excitation purity (Pe) measured by using the CIE illuminant C of less than 6%.
- Hereinafter, examples and comparative examples of the ultraviolet/infrared absorbent green glass of the present invention will be described.
- Lithium oxide, ferric oxide, titanium oxide, cerium oxide, metallic selenium, cobalt oxide, nickel oxide, chromium oxide, manganese oxide, copper oxide, neodymium oxide, erbium oxide, molybdenum oxide, vanadium pentoxide, lanthanum oxide and carbon based reducing agent, including carbon powder, etc., were added to the typical soda lime silica glass batch material as desired. The glass material thus prepared was held in an electric furnace at 1500° C. for 4 hours. The molten glass was cast on a stainless plate, and then annealed to the room temperature so as to obtain 6 mm thick glass plates.
- The obtained glass plates were polished, so that each glass plate has a thickness between 2.6 mm and 5 mm, so as to obtain the samples. Each sample was determined in optical properties including visible light transmittance (YA) measured by using the CIE illuminant A, total solar radiation transmittance (TG), ultraviolet transmittance (Tuv) defined by ISO 9050, dominant wavelength (DW) and excitation purity (Pe) measured by using the CIE illuminant C.
- The samples were also determined in physical properties including glass transition temperature (Tg), deformation temperature (Td), mean thermal expansion coefficient of the 50 to 350° C. range ((α(50-350)), Young's modulus (E) , surface compression and the temperature at which log η becomes 2. Each sample was formed into a rod-like shape having a length of 15 mm and a diameter of 5 mm, and then it was loaded with a load of 5 g and heated from the room temperature to 700° C. at a rate of 10° C. per minutes with silica glass rod prepared as a standard sample by the use of EXSTAR 6000 (SEIKO Electronics Inc.), so as to measure glass transition temperature (Tg), deformation temperature (Td) and mean thermal expansion coefficient of the 50 to 350° C. range (α(50-350)). Young's modulus (E) was measured with ultrasonic wave according to sing-around method, surface compression was measured with a Babinet-Style surface stress meter according to via-scope method, and the temperature at which log η becomes 2 was measured according to platinum ball drawing method.
- The glass composition and FeO/T-Fe2O3 ratio of each sample were shown in Tables 5 and 6. The contents of the components in these tables are indicated as percentage by weight. Tables 5 and 6 also show the optical properties and the physical properties of each sample.
TABLE 5 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 glass composition SiO2 70.8 70.9 69.5 69.5 68.2 68.3 [wt. %] Al2O3 1.74 1.88 1.71 1.91 2.87 2.87 MgO 4.09 4.02 3.19 3.11 1.64 1.65 CaO 7.94 7.96 8.26 8.44 9.21 9.22 Na2O 13.8 13.6 14.5 14.4 15.0 14.8 K2O 0.80 0.96 0.23 0.07 0.92 0.92 Li2O 0.05 0.09 0.06 0.12 0.16 0.33 T-Fe2O3 0.51 0.55 0.63 0.65 0.64 0.64 FeO/T-Fe2O3 0.23 0.24 0.32 0.31 0.22 0.18 TiO2 — — 0.09 0.14 0.16 0.16 CeO2 — — 1.65 1.65 1.17 1.17 optical thickness[mm] 5.0 3.5 4.0 3.4 3.1 3.1 properties YA[%] 78.5 80.3 72.9 75.3 77.0 77.5 TG[%] 54.9 59.7 45.5 49.5 49.6 50.7 Tuv[%] 24.5 32.4 8.6 10.1 15.0 15.3 DW[nm] 500 500 508 510 497 498 Pe[%] 2.4 1.9 2.6 2.2 3.1 2.9 physical Tg [° C.] 557.3 555.3 556.2 552.3 544.0 537.6 properties Td [° C.] 626.8 623.0 629.9 627.9 624.3 618.1 α(50-350) × e−7 92.9 93.1 94.3 93.9 100.8 101.8 E[GPa] 75.40 75.60 75.14 75.47 75.10 75.37 surface compressive 109.9 110.5 111.4 111.4 120.8 122.7 stress[MPa] temperature at which 1384 1381 1384 1383 1383 1380 log η becomes 2 [° C.] -
TABLE 6 Example 17 Example 18 Example 19 Example 20 Example 21 glass composition SiO2 68.3 67.9 70.0 69.0 69.5 [wt. %] Al2O3 2.87 2.85 1.70 2.40 1.90 MgO 1.65 1.64 2.70 1.70 1.70 CaO 9.23 9.16 8.04 9.11 9.00 Na2O 14.5 14.7 13.5 13.4 14.1 K2O 0.92 0.92 0.75 0.75 0.80 Li2O 0.50 0.33 1.50 2.00 1.00 T-Fe2O3 0.64 0.78 0.80 0.88 0.80 FeO/T-Fe2O3 0.18 0.27 0.26 0.24 0.24 TiO2 0.16 0.29 0.06 0.10 0.06 CeO2 1.17 1.44 0.65 0.60 0.87 optical thickness[mm] 3.1 2.6 2.6 2.6 2.6 properties YA[%] 77.2 75.0 75.7 74.9 76.5 TG[%] 50.1 47.0 47.6 43.9 49.6 Tuv[%] 15.3 12.7 15.6 11.8 15.0 DW[nm] 498 503 499 515 508 Pe[%] 3.0 2.6 2.6 2.7 2.4 physical Tg [° C.] 530.2 535.4 517.4 501.0 511.7 properties Td [° C.] 605.1 611.6 585.2 562.8 575.9 α(50-350) × e−7 101.6 100.6 101.6 101.7 101.7 E[GPa] 75.86 75.30 78.50 78.20 76.00 surface compressive 123.4 120.8 123.6 123.1 123.8 stress[MPa] temperature at which 1380 1381 1378 1377 1378 log η becomes 2 [° C.] - It is apparent from Tables 5, 6 that each glass of the present invention has the temperature at which log η becomes 2, which is an index of high temperature viscosity, so that the ultraviolet/infrared absorbent green glass of the present invention is excellent in meltability. Each ultraviolet/infrared absorbent green glass of the invention has also high surface compression, so that the ultraviolet/infrared absorbent green glass has large capacity for reinforcement.
- Examples 11-21 have preferable optical properties, such as: ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 35%, dominant wavelength (DW) measured by using the CIE illuminant C of 490 to 560 nm and excitation purity (Pe) measured by using the CIE illuminant C of smaller than 6% when each glass has a thickness between 2.1 mm to 6 mm.
- Examples 13-22 have more preferable optical properties to Examples 11 and 12 because ultraviolet transmittance (Tuv) of Examples 13-22 is lower than that of Examples 11 and 12.
- The glass composition, the optical properties and the physical properties of Comparative Examples 3 and 4 each of which was prepared in the same way as Examples 11-21 except for the glass composition are shown in Table 7.
TABLE 7 Comparative Comparative Example 3 Example 4 glass SiO2 71.3 69.9 composition Al2O3 1.55 1.48 [wt. %] MgO 4.02 3.13 CaO 7.99 8.49 Na2O 13.7 14.5 K2O 0.97 0.07 Li2O 0.00 0.00 T-Fe2O3 0.52 0.65 FeO/T-Fe2O3 0.22 0.31 TiO2 — 0.14 CeO2 — 1.65 optical thickness[mm] 3.4 3.4 properties YA[%] 82.9 75.4 TG[%] 63.9 49.7 Tuv[%] 32.2 10.0 DW[nm] 500 510 Pe[%] 1.7 2.2 physical Tg [° C.] 555.5 552.7 properties Td [° C.] 624.5 628.1 α(50-350) × e−7 92.7 93.6 E[GPa] 74.59 74.40 surface compressive stress 108.1 109.1 [MPa] temperature at which log 1410 1387 η becomes 2 [° C.] - Comparative Examples 3 and 4 are conventional ultraviolet/infrared absorbent glasses which do not include Li2O. These glasses have higher temperature at which log η becomes 2 and lower surface compression than those of the present invention, resulting in reduction of productivity and capacity for reinforcement.
- As described above, the present invention makes it possible to produce an ultraviolet/infrared absorbent glass having high visible light transmittance and greenish shade at lower cost than that of conventional ones, because the present invention reduces viscosity of the glass at high temperature. Particularly, the ultraviolet/infrared absorbent green glass of the present invention exhibits superior capacity for reinforcement, so that it is especially fitted for a window glass of a vehicle.
Claims (12)
1. Low transmittance glass composed of soda-lime-silica glass,
wherein said soda-lime-silica glass includes 0.001 to 2 wt. % Li2O and, as colorant, 0.7 to 2.2 wt. % total iron oxide expressed as Fe2O3 (T-Fe2O3); and
wherein said glass has visible light transmittance (YA) of not greater than 65%, measured by using the CIE illuminant A, total solar radiation transmittance (TG) of not greater than 60%, and ultraviolet transmittance (Tuv) defined by ISO 9050 of not greater than 25%, when said glass has a thickness between 2.1 mm and 6 mm.
2. Low transmittance glass as claimed in claim 1 , wherein Li2O is contained in an amount of less than 2 wt. %.
3. Low transmittance glass as claimed in claim 1 , wherein Li2O is contained in an amount of 0.05 to 0.5 wt. %.
4. Low transmittance glass as claimed in claim 1 , wherein said low transmittance glass includes FeO expressed as Fe2O3 in an amount of 20 to 50% of T-Fe2O3.
5. Low transmittance glass as claimed in claim 1 , wherein said low transmittance glass has base glass composition consisting essentially of:
65 to 80 wt. % SiO2;
0 to 5 wt. % Al2O3;
0 to 10 wt. % MgO;
5 to 15 wt. % CaO wherein a total amount of MgO and CaO is 5 to 15 wt. %; 10 to 20 wt. % Na2O;
0 to 5 wt. % K2O wherein a total amount of Na2O and K2O is 10 to 20 wt. %; and
0 to 5 wt. % B2O3.
6. Low transmittance glass as claimed in claim 1 , wherein said low transmittance glass includes at least one selected from the group consisting of Se, CoO, Cr2O3 and NiO as colorant.
7. Low transmittance glass as claimed in claim 6 , wherein said low transmittance glass includes 0.0001 to 0.1 wt. % Se.
8. Low transmittance glass as claimed in claim 6 , wherein said low transmittance glass includes 0.0001 to 0.1 wt. % CoO.
9. Low transmittance glass as claimed in claim 6 , wherein said low transmittance glass includes 0.001 to 2 wt. % Cr2O3.
10. Low transmittance glass as claimed in claim 6 , wherein said low transmittance glass includes 0.001 to 2 wt. % NiO.
11. Low transmittance glass as claimed in claim 1 , wherein said low transmittance glass includes at least one selected from the group consisting of TiO2, CeO2, MoO3, V2O5 and La2O3 as colorant in an amount of 0.0001 to 1 wt. %.
12. Low transmittance glass as claimed in claim 1 , wherein said low transmittance glass has visible light transmittance (YA) of 5 to 65%, measured by using the CIE illuminant A, total solar radiation transmittance (TG) of not greater than 50%, and ultraviolet transmittance (Tuv) defined by ISO 9050 not greater than 20%, when said glass has a thickness between 2.1 mm and 6 mm.
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JP2001197642A JP2003012342A (en) | 2001-06-29 | 2001-06-29 | Green glass absorbing uv and ir rays |
US10/166,064 US6753280B2 (en) | 2001-06-21 | 2002-06-11 | Ultraviolet/infrared absorbent green glass |
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- 2002-06-11 US US10/166,064 patent/US6753280B2/en not_active Expired - Fee Related
- 2002-06-13 EP EP02013445A patent/EP1270524B1/en not_active Expired - Fee Related
- 2002-06-13 DE DE60206445T patent/DE60206445T2/en not_active Expired - Fee Related
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US7754632B2 (en) * | 2003-08-13 | 2010-07-13 | Agc Glass Europe | Low-luminous-transmittance glass |
US20070191205A1 (en) * | 2003-08-13 | 2007-08-16 | Glaverbel | Low-luminous-transmittance glass |
US20070191208A1 (en) * | 2004-03-19 | 2007-08-16 | Saint-Gobain Glass France | Dark grey soda-lime-silica glass composition which is intended for the production of glazing |
US7884039B2 (en) * | 2004-03-19 | 2011-02-08 | Saint-Gobain Glass France | Dark grey soda-lime-silica glass composition which is intended for the production of glazing |
US20090181843A1 (en) * | 2005-10-31 | 2009-07-16 | Nippon Sheet Glass Company, Limited | Glass Article and Method of Producing the Same |
US8017537B2 (en) * | 2005-10-31 | 2011-09-13 | Nippon Sheet Glass Company, Limited | Glass article and method of producing the same |
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US20070099788A1 (en) * | 2005-11-02 | 2007-05-03 | Shelestak Larry J | Gray glass composition |
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US9115021B2 (en) * | 2011-09-14 | 2015-08-25 | Vidrio Plano De Mexico, S.A. De C.V. | Neutral grey glass compositions |
US20130335680A1 (en) * | 2012-06-15 | 2013-12-19 | Innolux Corporation | Organic light-emitting device and image display system employing the same |
US8890405B2 (en) * | 2012-06-15 | 2014-11-18 | Innolux Corporation | Organic light-emitting device and image display system employing the same |
US9337449B2 (en) | 2012-06-15 | 2016-05-10 | Innolux Corporation | Organic light-emitting device and image display system employing the same |
WO2015072938A1 (en) * | 2013-11-16 | 2015-05-21 | Türki̇ye Şi̇şe Ve Cam Fabri̇kalari A.Ş. | Privacy glass having low infrared transmittance |
US10427971B2 (en) | 2015-10-16 | 2019-10-01 | AGC Inc. | Ultraviolet-absorbing glass article |
Also Published As
Publication number | Publication date |
---|---|
DE60206445T2 (en) | 2006-05-18 |
EP1270524B1 (en) | 2005-10-05 |
US6753280B2 (en) | 2004-06-22 |
EP1270524A1 (en) | 2003-01-02 |
DE60206445D1 (en) | 2006-02-16 |
US20030083188A1 (en) | 2003-05-01 |
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Legal Events
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