EP1924532A1 - Procede pour eviter des defauts superficiels dans du verre plat flotte, verre plat et son utilisation - Google Patents
Procede pour eviter des defauts superficiels dans du verre plat flotte, verre plat et son utilisationInfo
- Publication number
- EP1924532A1 EP1924532A1 EP06775863A EP06775863A EP1924532A1 EP 1924532 A1 EP1924532 A1 EP 1924532A1 EP 06775863 A EP06775863 A EP 06775863A EP 06775863 A EP06775863 A EP 06775863A EP 1924532 A1 EP1924532 A1 EP 1924532A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- glass
- metal
- flat glass
- melt
- floating
- 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.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B18/00—Shaping glass in contact with the surface of a liquid
- C03B18/02—Forming sheets
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B18/00—Shaping glass in contact with the surface of a liquid
- C03B18/02—Forming sheets
- C03B18/20—Composition of the atmosphere above the float bath; Treating or purifying the atmosphere above the float bath
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
- C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
- C03B5/225—Refining
-
- 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
- C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
- C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
Definitions
- the invention relates to a method for the prevention of surface defects in floated flat glass, a flat glass obtained therewith, and to its use.
- TFT screens such as those used for computer monitors, or for TVs, telephone displays, etc.
- An essential prerequisite for the production of such TFT screens is a completely flat, thin plate glass, which also has a particularly smooth and flat surface in addition to a good electrical insulation and a relatively high melting point.
- JP 2004-189535 describes the production of glass plates with a dimension of 300 mm edge length and a thickness of 0.7 mm. Further production of such TFT glasses according to this plate casting method is also described in JP 10-130034 A, for example.
- float glass Another way to produce flat glass is to float glass.
- a float method is generally known and described, for example, in US Pat. No. 2,911,759.
- an endless glass ribbon having desired dimensions in width and thickness is prepared by continuously pouring molten glass onto the surface of a bath of molten metal.
- molten metal now floating on the floating glass, such as oil on water.
- the temperatures in and especially over the molten metal have a hotter and a colder area, wherein the molten glass is applied in the hot area and slowly in the colder area in the solidified supply. stood up and discharged. Due to the speed of the glass application and the glass discharge from the tub, it is possible to adjust the thickness of the respective glass band.
- One commonly used metal for this process is molten tin.
- the hot tin is highly sensitive to oxidation, so that the float process is carried out under an atmosphere of forming gas, which is about 10 vol. % H 2 and 90 vol.% N 2 . In this way, the oxidation of the liquid tin to SnO 2 is avoided, which would lead to the destruction of the molten metal.
- DE 102 09 742 A1 describes a process for producing float glass in which the oxygen concentration over the molten metal is to be adjusted in such a way that at no point does it exceed the saturation solubility of oxygen in the metal bath End, that is at the place of the discharge of the metal bath, prevails.
- US-A-4, 081, 262 in order to avoid the defects described above, it is proposed to arrange a curtain of reducing gas which protects the exposed surface of the tin bath from oxidation. Further, US-A-3,356,476 discloses removing surface defects of the glass by drawing off a portion of the atmosphere above the bath and re-circulating the bath after cooling. During this process, impurities are also removed from the gas during the cooling process, for example when flowing through a bed of silica gel.
- arsenic-refined glass is not suitable for float processes since it is known that arsenic-refined glasses tend to have brownish, dark discolorations, known as lead or arsenic levels, under the conditions encountered in flooding. Such undesirable discolorations under the reducing conditions in the production of flat glass by flooding are described, for example, in US Pat. No. 4,015,966.
- the content of hydrogen in the atmosphere above the float glass is at most 7% by volume, with a maximum of 6% by volume being preferred. Particularly preferred is a maximum hydrogen content of 5% by volume, with 3% by volume being even more preferred. Very particular preference is given to an atmosphere which contains a maximum of 1% by volume of hydrogen.
- the atmosphere that prevails over the glass is separated from the atmosphere that is exposed to the, that is not with Glass covered surface of the molten tin comes into contact.
- the latter expediently contains hydrogen, preferably in an amount of at least 10% by volume.
- the adjustment according to the invention of the oxygen activity in the glass takes place by adding metals or oxides thereof whose formation enthalpy ⁇ G ° at the float temperatures is either below (first group) or above (second group) that of Sn / SnO 2 .
- metals / metal oxide systems can be found, for example, in a Richardson-Ellingham diagram.
- the adjustment of the oxygen activity according to the invention presupposes that the oxygen activity of the glass or of the melt has previously been determined.
- customary auxiliaries and methods are described by Baucke (FGK Baucke: Electrochemical cells for on-line measuring of oxygen fugacities in glass-forming melts., Glastechn., Ed., 61 (1988), 87).
- These are of course polyvalent metals, ie metals with at least two different, ie at least two positive oxidation states or cationic oxidation states.
- the free enthalpy of formation .DELTA.G is at least 10 kJ / mol, preferably at least 20, in particular at least 30 kJ / mol above or below the aforementioned system.
- the added redox systems particularly preferably have an enthalpy of formation which, at the float temperatures, is at least 50, in particular at least 70, and very particularly at least 100 kJ / mol above or below that of Sn / SnO 2 .
- tall / metal oxides have a free enthalpy of formation of at least -575.8 + 0.21-T [K], where T is the temperature at K in floatation.
- Preferred temperatures of the floating according to the invention are 600 - 1250 0 C, wherein the hot temperature range of the float bath is greater than 1000 0 C is particularly preferred.
- Further preferred minimum values are -560, in particular -555, with -550 + 0.21-T [K] being particularly preferred.
- Further preferred minimum values are 50, in particular 70 kJ / mol, and in particular 100 kJ / mol, above the aforementioned minimum value.
- Preferred metals / metal oxides of this first group are in particular Cu, Ni, As, Bi, and optionally Au, Ag and Pt, with Ni and As being particularly preferred.
- Metal / metal oxide systems having a free formation enthalpy below the aforesaid value have a ⁇ G ° of at most -580 + 0.21-T [K], with at most -585 and -590, especially -600 + 0.21-T [K] being most preferred are. Further particularly preferred values are 30, in particular 50, preferably 70 kJ / mol below the abovementioned maximum limit of 150.
- Preferred metals / metal oxides of the second group are in particular Fe, Zn, Cr, Mn, Ti and V.
- the inventively added metals or metal oxides of the first and the second group are preferably present in a concentration of 5 ppm - 50,000 ppm.
- Preferred minimum amounts are 50 ppm, in particular 500 ppm, with at least 1000 ppm being particularly preferred.
- Preferred maximum amounts are 30,000 ppm, in particular 20,000 ppm, wherein 15,000 ppm, in particular 10,000 ppm are particularly preferred.
- the addition of elements or their oxides of the first group ie those which avoid the reduction of SnO 2 to SnO or oxidize or form SnO 2 to SnO 2 , is particularly preferred.
- Such metals or metal oxides are added, which do not form a network with the other glass components or polymerize with these not to glass backbone.
- Preferred additives according to the invention are so-called network converters or else intermediate oxides with an increased ionic character.
- inventive method is possible in principle with all glass compositions.
- glasses which consist essentially of SiO 2 , Al 2 O 3 , alkaline earth oxides, in particular CaO and / or MgO, and, if appropriate, B 2 O 3 .
- Preferred glasses have no alkali oxides.
- Aluminosilicate glasses preferred according to the invention contain at least 67% by weight of SiO 2 , with at least 67.5% by weight and in particular at least 68% by weight being particularly preferred.
- the maximum limit of SiO 2 is 74% by weight, in particular less than 73% by weight, with at most 69% by weight being very particularly preferred.
- B 2 O 3 is in the glass according to the invention in an amount of at least 5 wt .-%, in particular at least 7 wt .-%, with minimum contents of 9 wt .-%, in particular 9.5 wt .-% are particularly preferred.
- the maximum contents of B 2 O 3 in the glass according to the invention are 10% by weight, with 9.95% by weight being preferred.
- Al 2 O 3 is present in the glass according to the invention in an amount of at least 3% by weight, in particular at least 5% by weight and preferably preferably at least 5.5 wt .-%, wherein the maximum amount is 20 wt .-%, in particular 15 wt .-% and preferably 10 wt .-%. Particularly preferred is a maximum content of Al 2 O 3 of 6.5 wt .-%.
- Li 2 O is contained in the glass according to the invention in an amount of 0 to at most 4 wt .-%, with minimum amounts of 0.5 wt .-% and in particular 1 wt .-% are preferred. A particularly preferred minimum range of Li 2 O is 1.5% by weight.
- the maximum amount of Li 2 O is a maximum of 4 wt .-%, in particular up to 3 wt .-%, with upper limits of at most 2.5 wt .-% and especially 2.0 wt .-% are particularly preferred.
- the content of Na 2 O and K 2 O in the glass according to the invention is 0 to a maximum of 10% by weight, with a maximum limit of not more than 5% by weight, preferably not more than 4% by weight being preferred for Na 2 O.
- the preferred maximum amount is 8% by weight, in particular 7% by weight.
- the sum of the alkali oxides Li 2 O, Na 2 O and K 2 O in the glass according to the invention is 0% by weight and at most 10.5% by weight, with minimum amounts of 0.5% by weight, in particular 2% by weight.
- % and maximum amounts of 10 wt .-%, in particular 9 wt .-% and preferably at most 7 wt .-% are still suitable.
- very particular preference is given to alkali-free glasses.
- the content of MgO, CaO, SrO, BaO and ZnO in the glass according to the invention is in each case independently from 0 to a maximum of 10% by weight, with a maximum amount of 5% by weight being usual for MgO.
- a preferred minimum amount of MgO and CaO in the glass according to the invention is in each case independently of one another 0.5% by weight, the preferred maximum amount of MgO and CaO being in each case independently 12% by weight and preferably 8% by weight.
- the sum of the alkaline earth oxides MgO, CaO, SrO, BaO and the transition oxide ZnO in the glass according to the invention is 0-20% by weight, with contents of up to 18% by weight, in particular of up to 15% by weight, being particularly preferred.
- TiO 2 and / or ZrO 2 are contained in the glass according to the invention in amounts of from 0 to a maximum of 3% by weight, with a minimum amount of 0.5% by weight, preferably 0.8% by weight and a maximum amount of 2 wt .-%, in particular 2.5 wt .-% and especially 1.2 wt .-% is particularly preferred.
- the glass according to the invention preferably contains, in addition to TiO 2, a content of MoO 3 and / or Bi 2 O 3 , wherein the content of MoO 3 is advantageously 0-3 wt.% And Bi 2 O 3 is in each case independently 0-5 wt. -% is.
- the sum of both oxides is preferably 0.01-5 wt .-%.
- a minimum amount of 0.1 wt .-% in particular a minimum amount of 0.2 wt .-%, and a maximum amount of 3 wt .-% for both together.
- Bi 2 O 3 also greatly improves the solarization stability of the glass. Very particular preference is given to a minimum content of MoO 3 of 0.6% by weight or a minimum content of Bi 2 O 3 of 1.3% by weight.
- the glass according to the invention is very stable against solarization under UV irradiation, its solarization stability is due to low levels of PdO, PtO 3 , PtO 2 , PtO, RhO 2 , Rh 2 O 3 , IrO 2 and / or Ir 2 O 3 can be further increased.
- sum amounts of the above oxides in an amount of at most 0.1 wt .-%, preferably at most 0.01 wt .-%, in particular at most 0.001 wt .-% proved to be particularly suitable.
- the minimum content for these purposes is usually 0.01 ppm, with at least 0.05 ppm and in particular at least 0.1 ppm being preferred.
- the glass of the present invention may contain small amounts of CeO 2 , PbO and Sb 2 O 3 for increasing chemical resistance and processability, they are preferably free thereof. If iron is present, it is converted by the oxidizing conditions during the melt in its oxidation state 3 + and thus causes no discoloration in the visible wavelength range more.
- the glass according to the invention is lauterable in the usual way, but a refining with arsenic, antimony and / or tin is preferred. Particularly preferred is a combined refining with at least two of the aforementioned refining agents, if appropriate also together with further refining agents. In this case, a content of the refining agent at 5 ppm to 10,000 ppm (1 wt .-%) is preferred. Appropriate minimum amounts are 50 ppm, in particular 100 ppm. Appropriate maximum levels are 8000 ppm and 5000 ppm.
- the invention also relates to a flat glass obtained by the method, as well as its use for the production of electronic devices.
- Preferred electronic devices are TFT monitors, LCD monitors, for so-called chip-on-glass, and for solar cells, in particular for photovoltaics.
- the glasses according to the invention for waferbondcalled waferbondmme insulators, especially so-called SOI, Silicon Insulator, and MEMS (Micro-Engineering And Mechanical Systems).
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Glass Compositions (AREA)
Abstract
L'invention concerne un procédé pour éviter un dépôt superficiel et/ou des défauts sous forme de trous de type cratères lors de la production de verre plat flotté. Ce procédé consiste à produire du verre fondu, à affiner ce dernier et à faire flotter le verre fondu affiné sur une surface constituée de métal liquide sous atmosphère inerte. Ce procédé est caractérisé en ce que l'on i) limite la teneur en hydrogène dans le gaz inerte à 7 % en volume au maximum et ii) ajuste la pression partielle d'oxygène dans le verre fondu flottant a) au moyen d'un métal dont l'enthalpie de réaction pour l'oxydation ?G° (Me /MexOy) est > -575,8 + 0,21 T[K] ou b) au moyen d'un métal dont l'enthalpie de réaction pour l'oxydation ?G° (Me /MexOy) est < -575,8 + 0,21 T[K].
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102005039378A DE102005039378A1 (de) | 2005-08-19 | 2005-08-19 | Verfahren zur Vermeidung von Oberflächendefekten bei gefloatetem Flachglas |
PCT/DE2006/001434 WO2007019840A1 (fr) | 2005-08-19 | 2006-08-17 | Procede pour eviter des defauts superficiels dans du verre plat flotte, verre plat et son utilisation |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1924532A1 true EP1924532A1 (fr) | 2008-05-28 |
Family
ID=37139133
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP06775863A Withdrawn EP1924532A1 (fr) | 2005-08-19 | 2006-08-17 | Procede pour eviter des defauts superficiels dans du verre plat flotte, verre plat et son utilisation |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP1924532A1 (fr) |
JP (1) | JP2009504559A (fr) |
KR (1) | KR20080038231A (fr) |
DE (1) | DE102005039378A1 (fr) |
WO (1) | WO2007019840A1 (fr) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102007007577B4 (de) * | 2007-02-15 | 2016-01-14 | Schott Ag | Verfahren zur Vermeidung von Oberflächendefekten bei keramisiertem, gefloatetem Flachglas |
JP4958007B2 (ja) * | 2007-11-13 | 2012-06-20 | 日本電気硝子株式会社 | ガラス板製造方法およびガラス板製造装置 |
CN102922213B (zh) * | 2012-11-21 | 2014-12-03 | 苏州永创金属科技有限公司 | 一种低温、无色差修补镀银工件表面缺陷的方法 |
DE102014203564B4 (de) * | 2014-02-27 | 2018-05-03 | Schott Ag | Floatverfahren zur Herstellung einer Floatglasscheibe und Floatglasscheibe |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB769692A (en) * | 1953-12-10 | 1957-03-13 | Pilkington Brothers Ltd | Improvements in or relating to the manufacture of flat glass |
US3305337A (en) * | 1962-07-30 | 1967-02-21 | Pilkington Brothers Ltd | Method of manufacture of flat glass on molten tin |
GB1020588A (en) * | 1963-05-16 | 1966-02-23 | Pilkington Brothers Ltd | Improvements in or relating to the manufacture of flat glass in ribbon form |
US3356476A (en) * | 1965-02-08 | 1967-12-05 | Pittsburgh Plate Glass Co | Method of removing contaminates from the protective atmosphere of a glass sheet float bath |
US3954432A (en) * | 1974-10-15 | 1976-05-04 | Ppg Industries, Inc. | Method for improving the quality of flat glass formed on a bath of molten tin |
US3925052A (en) * | 1974-10-15 | 1975-12-09 | Ppg Industries Inc | Method of improving quality of flat glass formed on molten tin |
US4015966A (en) * | 1976-06-01 | 1977-04-05 | Owens-Illinois, Inc. | Manufacture of X-ray absorbing glass composition by a float glass process |
US4081262A (en) * | 1977-08-03 | 1978-03-28 | Ppg Industries, Inc. | Use of reducing gas curtain for start of glass forming process |
LU83164A1 (fr) * | 1980-03-04 | 1981-06-05 | Bfg Glassgroup | Verre colore et son procede de fabrication |
JP3800443B2 (ja) * | 1996-10-22 | 2006-07-26 | 日本電気硝子株式会社 | ディスプレイ用無アルカリガラス基板及びその製造方法 |
US6065309A (en) * | 1997-09-20 | 2000-05-23 | Wisconsin Alumni Research Foundation | Float processing of high-temperature complex silicate glasses and float baths used for same |
DE10209742A1 (de) * | 2002-03-06 | 2003-09-18 | Schott Glas | Verfahren zur Herstellung von Floatglas |
JP4305817B2 (ja) * | 2002-12-11 | 2009-07-29 | 日本電気硝子株式会社 | 無アルカリガラス基板 |
-
2005
- 2005-08-19 DE DE102005039378A patent/DE102005039378A1/de not_active Withdrawn
-
2006
- 2006-08-17 JP JP2008526369A patent/JP2009504559A/ja active Pending
- 2006-08-17 WO PCT/DE2006/001434 patent/WO2007019840A1/fr active Application Filing
- 2006-08-17 KR KR1020087006527A patent/KR20080038231A/ko not_active Application Discontinuation
- 2006-08-17 EP EP06775863A patent/EP1924532A1/fr not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO2007019840A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE102005039378A1 (de) | 2007-02-22 |
KR20080038231A (ko) | 2008-05-02 |
JP2009504559A (ja) | 2009-02-05 |
WO2007019840A1 (fr) | 2007-02-22 |
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Inventor name: BEIER, WOLFRAM Inventor name: DAHLMANN, ULF |
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