Classifications

• • 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

Definitions

• the invention relates to new glass compositions of the soda-lime-silica type.
• This type of glass composition is commonly used in the "flat glass” industry, that is to say the glass industry supplying glazing for industries such as the building and automotive industries.
• the usual glazing manufacturing techniques for these industries consist first of melting raw materials, which will make it possible to obtain the desired glass composition, then forming a glass ribbon on a bath of molten metal according to the process " float ".
• the cost of alkaline oxides and in particular sodium oxide Na 2 O can account for 60 to 80% of the price of the composition.
• the content of alkaline oxides in the most conventional compositions is greater than 13.5% and most often greater than 14%.
• the alkaline oxides more particularly have the function of helping the melting of the composition and of reducing the viscosity at high temperatures. Reducing the contents of alkaline oxides while preserving conventional manufacturing conditions, in particular melting and refining conditions, without the risk of devitrification, in particular during the forming of the glass ribbon therefore seems difficult without changing the conditions for melting or working the glass.
• the inventors have nevertheless given themselves the mission of producing new, more economical silica-soda-lime-type glass compositions can be melted and then transformed into glass ribbon, without modification of the usual installation or their conditions of use.
• this object is achieved by a glass composition of the soda-lime-silica type intended to be transformed into flat glass according to the float process, the content of alkali oxides expressed as a percentage by weight, is between 9 and 13, 3%.
• the content of alkaline oxides is greater than 12.50% and more preferably still greater than 13%.
• Such alkali contents notably improve the durability of refractories.
• the alkaline oxides present in the compositions are essentially Na 2 0 and K 2 O.
• the oxide K 2 O is advantageously present in the form of an impurity.
• the Na 2 O content is thus between 7 and 13.3% and preferably it is greater than 11.1% and more preferably still greater than 12.5%.
• the sum of the contents of the CaO and MgO oxides is less than 13%. According to this variant, the sum of the contents of the CaO and MgO oxides is lower than that of the compositions usually melted for producing flat glass on float. This decrease in the content of these oxides can contribute to reducing the risk of devitrification by lowering the devitrification temperature.
• a drop in density and therefore a reduction in surface area may interest the automobile industry which increasingly aims to reduce the weight of vehicles, in particular for those powered by electric energy.
• log ⁇ 14.6
• the matrix of the glass composition comprises the following constituents in the following weight proposals:
• compositions thus defined according to the invention show, compared to the compositions usually melted and transformed into flat glass according to the float process, a drop in the Na 2 O oxide contents which leads to savings from the point of view of material costs. raw. Furthermore, the contents of alkaline earth oxides, and more particularly the CaO content, are reduced, in particular to limit the risks of devitrification and reduce the density of the glass. This last characteristic, a decrease in the density of the glass, is reinforced by the fact that the decreases in the oxide contents which have just been mentioned are compensated for by an increase in the silica content always in comparison with the compositions usually melted to form glass. flat using the float process.
• alumina AI 2 O 3 its content can reach 1.6% due to the content of certain sands used as raw materials. This content of Al 2 O 3 is however advantageously less than 1% and more preferably still less than 0.6%. Alumina is however advantageously present with a content of at least 0.2%, in particular for its role as stabilizer.
• the content of oxide K 2 O can reach 1.5%, this can also be provided by certain sands used as raw material.
• the potash content is however advantageously less than 0.5% and preferably less than 0.2%.
• the glass composition according to the invention can comprise other constituents, in particular all the constituents known to those skilled in the art for producing colored glasses.
• composition of glass, non-colored, very particularly advantageous is such that its matrix comprises the following constituents in the following weight proposals:
• compositions compared are the following: (the contents are expressed in percentages by weight).
• composition A shows a fusibility of composition A little different from that of composition B.
• T iiq is the liquidus temperature
• composition according to the invention can have a slightly more delicate melting than that of composition B.
• the compositions according to the invention therefore allow melting and forming of the glass according to the float process with a significantly reduced cost of raw materials. Furthermore, the density of the glass formed from these compositions is lower than that of the previous compositions, which also leads to a significant saving. In fact, if the variation in density which appears between compositions A and B does not seem significant, it should be noted that this variation intervenes directly on the cost of the finished product.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Glass Compositions (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1997
  • 1997-07-01 FR FR9708261A patent/FR2765569B3/fr not_active Expired - Fee Related
• 1998
  • 1998-07-01 WO PCT/FR1998/001406 patent/WO1999001391A1/fr not_active Application Discontinuation
  • 1998-07-01 EP EP98935073A patent/EP0928286A1/fr not_active Withdrawn
  • 1998-07-01 CO CO98037151A patent/CO5050399A1/es unknown
  • 1998-07-01 JP JP11506535A patent/JP2001500099A/ja active Pending
  • 1998-07-01 KR KR1019997001303A patent/KR20000068187A/ko not_active Application Discontinuation
  • 1998-07-01 CN CN98800920A patent/CN1230937A/zh active Pending
  • 1998-07-01 BR BR9806100-3A patent/BR9806100A/pt unknown
  • 1998-07-01 ZA ZA985760A patent/ZA985760B/xx unknown
  • 1998-07-01 TR TR1999/00420T patent/TR199900420T1/xx unknown
  • 1998-07-01 PL PL98331823A patent/PL331823A1/xx unknown

Non-Patent Citations (1)

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