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
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/14—Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
• • 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
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/24—Fusion seal compositions being frit compositions having non-frit additions, i.e. for use as seals between dissimilar materials, e.g. glass and metal; Glass solders
  • C03C8/245—Fusion seal compositions being frit compositions having non-frit additions, i.e. for use as seals between dissimilar materials, e.g. glass and metal; Glass solders containing more than 50% lead oxide, by weight

Definitions

• the present invention is concerned generally with sealing glass compositions, in
• sealing glass paste for sealing glass
• the invention renders a PbO-containing
• sealing glass suitable for use in combination with a vehicle that includes much lower
• VOC volatile organic compounds
• glass modifier of the present invention therefore allows the sealing process to be carried
• PbO-containing sealing glasses and particularly PbO/B 2 O 3 /ZnO sealing glasses,
• cathode ray tube such as a color television picture tube.
• sealing glasses have the
• sealing glasses (sometimes referred to as “solder” glasses) are
• crystallized glass has a melting point temperature that is higher than the fiber softening
• the seals also must have good dielectric
• processing steps include the separate and successive application to the face
• a carbon or graphite background may be used to cover the face plate.
• a carbon or graphite background may be used to form a carbon or graphite background.
• a resinous or plastic film may be applied to the surface
• aluminized surface is connected to a metal stud on the inner surface of the face plate.
• a sealing glass is applied to the mating edge surfaces of the funnel.
• the PbO constituent in the sealing glass has a natural propensity or tendency to be
• any dielectric breakdown in the seal between the funnel and face plate will provide a source of
• Sealing glasses typically are applied to the mating edge surfaces of the funnel in
• the paste is made by combining the sealing glass with a vehicle that holds
• the glass frit in a ribbon form for a period of time sufficient to enable the resultant paste to
• the mating pieces e.g., in the case of a color television tube
• vehicle constituents must be pyrolyzable when they are subjected to a temperature below
• Conventional vehicles generally comprise a binder and a solvent.
• the only binder is the binder
• nitrocellulose usually as a 1 to
• cellulose and hydroxypropyl cellulose may be used as binders for PbO-containing sealing
• nitrocellulose is particularly preferred because it tends to decrease the reduction
• Amyl acetate and butyl acetate are the preferred solvents for use in sealing glass
• Ethylene glycol methyl ether also is a suitable binder
• binder solvents that may be used.
• the amount of solvent in the paste will depend upon
• the desired paste consistency but will usually comprise about five to about fifteen weight
• the amount of vehicle necessary for the paste is the amount that will maintain the
• the ribbon must be wide enough to produce an
• the weight of the ribbon being extruded for a given length may vary appreciably over time
• dispensing apparatus must carefully monitor the ribbon and adjust the volume of the paste
• sealing glass solids including refractory
• fillers, nucleating agents, and any modifiers) to vehicle is usually in the range of about
• the paste obtained by combining the vehicle with the sealing glass is
• seals formed from pastes that employ nitrocellulose as a binder are less
• nitrocellulose is thought to provide a source of oxygen during heating of the sealing glass
• the devitrified seals formed by these other binders is gray or gray-black
• glass frit did not eliminate the need for the use of at least some nitrocellulose binder.
• containing sealing glasses include nitrocellulose, which in turn requires the use of a
• VOC-free or low-VOC vehicle capable of being used with a VOC-free or low-VOC vehicle, and particularly an aqueous
• low-VOC vehicle includes VOC-free formulations.
• This invention aids in fulfilling these needs in the art by providing a sealing glass
• modifier means any substance that
• the modifier comprises an inorganic nitrate
• the inorganic nitrate is Bi(NO 3 ) 3 5H 2 O and/or Zn(NO 3 ) 2
• the modifier of the present invention may be incorporated as a component of the
• the modified frit glass comprises a PbO-containing glass frit having a
• sealing or firing temperature within the temperature range of about 420° C. to about 460°
• the invention includes a sealing
• the modifier also may be dissolved or dispersed in a sealing glass vehicle for a
• the modified vehicle comprises a VOC-free or low-VOC vehicle
• the invention further includes a sealing glass
• the invention includes a method of sealing a face plate to the funnel of
• the sealing temperature range of between about 420° C. and about 460° C. for a period of
• this invention includes a method of sealing a face plate to the funnel of a
• cathode ray tube using a PbO-containing sealing glass in a VOC-free or low-VOC vehicle using a PbO-containing sealing glass in a VOC-free or low-VOC vehicle
• steps of A Combining the sealing glass with a modifier in an amount sufficient to prevent the PbO from being chemically reduced when the sealing glass is fired at a
• the sealing temperature range of between about 420° C. and about 460° C. for a period of
• this invention provides a method of sealing a face plate to a funnel of
• the sealing temperature range of between about 420° C. and about 460° C. for a period of
• PbO-containing sealing glass to be used in combination with a VOC-free or low-VOC
• the modifier preferably comprises an inorganic nitrate that is
• the modifier is added to the sealing glass system in an amount sufficient to
• invention includes the use of a modifier in a sealing glass system to decrease the reduction
• glass paste including the modified sealing glass, a vehicle inco ⁇ orating the modifier, a
• sealing glass paste including the modified vehicle, the methods of making the modified
• the present invention provides a sealing glass modifier that decreases the
• sealing or firing enables the sealing glass to be used in combination with a VOC-free
• the modifier preferentially comprises bismuth nitrate and/or zinc
• the sealing glass is fired in the presence of reducing conditions at a temperature sufficient
• Lead-zinc-borate solder glasses are preferred in practicing this invention. Such as
• base glass also are referred to herein as the "base glass.”
• the lead-zinc-borate glasses suitable for use in the present invention typically include
• Table 1 expressed in weight percent, and wherein the total content of all oxides is 100%.
• Li,0, CdO, and Fe 2 0 3 can be included. However, it is preferred in many instances not to
• compositions that consist essentially only
• the particle size of the glass frit is not particularly critical to the practice of the
• the particle size of the glass frit will be such that about 100% of the particles
• the base glass used in the practice of this invention have the same
• a VOC-free vehicle that reasonably satisfies the requirements that the vehicle be
• free vehicle is a colorless liquid comprising 97-98% water and less than 2% cellulose. It
• sealing glass solids including refractory fillers, nucleating
• VOC-free or low-VOC vehicle such as vehicle
• the modifier of the present invention preferably comprises an
• the modifier is added to the sealing glass system in
• Bi(NO 3 ) 3 5H 2 0 and/or Zn(NO 3 ) 2 6H 2 0 are the particularly preferred modifiers.
• the sealing glass paste or on the sealing properties of the base glass are the sealing glass paste or on the sealing properties of the base glass.
• modifier also may be shown by dielectric tests of the resultant seal.
• samples were prepared by inco ⁇ orating a modifier (in an amount equal to about 1 % by
• the samples were fired at a temperature of about 420° C. to about 460° C.
• VOC-free vehicle A9065 in a weight ratio of about 8.3: 1 and fired at a temperature of
• porous appearance which is indicative of low seal strength and an increased likelihood of
• the effective amount of the modifier typically will be in the range of about
• sealing glass powder This may be accomplished, for example, using the two-step
• sealing glass powder is blended in a twin shell or rotocone blender for about 5 to about
• the material from Step 2 is referred to as a modifier masterblend.
• a desired modifier masterblend A desired
• amount of the modifier masterblend may be uniformly dispersing in the final sealing
• a sealing glass paste of the present invention may be prepared by mixing the
• the modified vehicle of this invention may be prepared by dissolving an
• the amount of modifier added to the vehicle to create the modified vehicle generally includes
• Another sealing glass paste of the present invention may be prepared by mixing
• the weight ratio of sealing glass solids to vehicle is usually
• the present invention includes a method of sealing a face plate to the funnel of
• sealing amount of the sealing glass composition of this invention and B. Subjecting the applied sealing glass composition to a sealing temperature within
• the sealing temperature range of between about 420° C. and about 460° C. for a period
• this invention includes a method of sealing a face plate to the funnel of
• the sealing temperature range of between about 420° C. and about 460° C. for a period
• this invention provides a method of sealing a face plate to a funnel
• a cathode ray tube such as a color television tube
• sealing glass comprising the steps of:
• the sealing temperature range of between about 420° C. and about 460° C. for a period
• sealing glass pastes made with a VOC-free vehicle such as A9065
• the conventional vehicle system have a stable rheology for about 0.5 to about 8 hours
• VOC-free pastes have commercially useful, but not optimal rheology and shelf-life

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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 (2)

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Family Applications (1)

Country Status (5)

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Citations (2)

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• 1997
  • 1997-04-01 KR KR1019970708792A patent/KR19990022312A/ko not_active Application Discontinuation
  • 1997-04-01 JP JP9535533A patent/JPH11507005A/ja active Pending
  • 1997-04-01 EP EP97917762A patent/EP0828693A4/de not_active Withdrawn
  • 1997-04-01 WO PCT/US1997/005298 patent/WO1997036836A1/en not_active Application Discontinuation
  • 1997-12-02 MX MX9709381A patent/MX9709381A/es unknown

Patent Citations (2)

Non-Patent Citations (4)

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