US3723144A - Borosilicate opal glasses - Google Patents

Borosilicate opal glasses Download PDF

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Publication number
US3723144A
US3723144A US00141765A US3723144DA US3723144A US 3723144 A US3723144 A US 3723144A US 00141765 A US00141765 A US 00141765A US 3723144D A US3723144D A US 3723144DA US 3723144 A US3723144 A US 3723144A
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United States
Prior art keywords
opal
glasses
phase
glass
borosilicate
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Expired - Lifetime
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US00141765A
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English (en)
Inventor
J Flannery
J Lemoine
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Corning Glass Works
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Corning Glass Works
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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
    • C03C4/00—Compositions for glass with special properties
    • C03C4/005—Compositions for glass with special properties for opaline 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
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • 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
    • 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
    • C03C2204/00—Glasses, glazes or enamels with special properties
    • C03C2204/04—Opaque glass, glaze or enamel

Definitions

  • This invention relates to the production of borosilicate opal glasses wherein the opal phase is readily attacked by water and detergents.
  • the opal phase is made discontinuous, i.e., the particles thereof commonly exhibit a spherical configuration, such that deep leaching is inhibited.
  • the glasses consist essentially, in weight percent on the oxide basis, of 0.5-2.5% Li O, 710% ZnO, 11-14% B 0 and 71-76% SiO CROSS REFERENCE TO RELATED APPLICATION U.S. application Ser. No. 94,834, filed Dec. 3, 1970 in the names of Gerald B. Carrier and James E. Flannery.
  • a translucent or almost opaque white glass can be produced through the inclusion therein of colorless, nonmetallic crystalline or amorphous particles. These particles, having a dilferent index of refraction from that of the base glass, scatter the light within the body of the glass and diffuse the transmitted light.
  • Such glasses have been referred to as opals and have seen such diversitied applications as tableware, culinary ware, lamp globes, and wall paneling.
  • the opacity exhibited by opal glasses is dependent upon a phase separation occurring within the body of the glass wherein a light-diffusing phase is uniformly precipitated throughout a transparent glassy matrix.
  • the light diffusing effect results from the fact that the separated phase, whether it be amorphous, crystalline, or only voids, has an index of refraction different from that of the matrix glass such that light scattering with consequent loss of transparency occurs.
  • the opacifying phase may be relatively continuous through all or a portion of the glass body. Conversely, it can be particulate or otherwise relatively discontinuous. Where the separated phase is continuous within itself, deep leaching can occur. However, if the precipitated phase can be made discontinuous, then paths for leaching will not be available and only those portions of the soluble phase which are exposed at the surface of the glass will be dissolved. This, of course, presupposes that the baseglass is relatively inert to the attacking medium.
  • an opalizing agent is included in the glass batch which will form a compound that is soluble in the 'glass melt but which will precipitate therefrom during the cooling of the melt to an amorphous body or upon a subsequent heat treatment thereof.
  • Opal glasses produced from conventional soda lime glass composition were Well known to the art and commonly utilized metal halide, sulfate, or phosphate salts as opalizers. Nevertheless, the high coefficients of thermal expansion exhibited by these glasses, viz., up to 90X C. over the range 25 -300 C., foreclosed their use where reasonable resistance to thermal shock was required, as, for example, in ovenware.
  • opal glasses having a borosilicate base composition were developed. These glasses demonstrate coefficients of thermal expansion over the range 25 300 C. between about ZS-SOX 10 C. and, therefore, exhibit sufficient thermal shock resistance for use in glassware applications involving high temperature gradients resulting from zone heating or thermal cycling.
  • U.S. Pat. No. 3,275,492 describes one group of such borosilicate-type glasses having good resistance to thermal shock within a broad range of opal densities.
  • Opalizing agents for borosilicate-type glasses include ZnO, MgO, CaO, BaO, NiO, CoO, MnO, and C with, optionally, such secondary opalizers as the halides, phosphates, or sulfates.
  • These glasses exhibit good melting and forming properties but, unfortunately, are subject to chemical attack from certain commonplace solutions. For example, tableware and culinary ware made therefrom manifest surface attack after being in contact with hot detergent solutions such as are experienced in dishwashers. This chemical attack all too soon leads to surface roughness which, in itself, is aesthetically unpleasing and further entrains staining from food coming into contact therewith.
  • the preferred opal glasses contain 1-6% of alkali metal oxides, 3-4% total of the bivalent metal oxides ZnO, CaO, and MgO, and 0.2-3% total of M00 W0 and As O Electron micrograph comparisons of the internal structures of conventional borosilicate opal glasses and the opal glasses of that invention showed a significant difference in the microstructure of the precipitated phase.
  • the opacifying phase appeared as a series of interconnecting, irregularly-shaped droplets scattered throughout the cross section.
  • the separated phase in the new glasses appeared as individual, disconnected droplets.
  • the opal products of that invention exhibited a soft white appearance whereas, for such applications as dinnerware and culinary ware, a bright white body is seemingly highly desirable to the user.
  • the principal object of the instant invention is to produce an opal borosilicate glass exhibiting a very bright white appearance with improved chemical durability, the improved chemical durability being due to the opacifying phase being present in the form of very small, discontinuous, spherically-shaped droplets, wherein the glass batch consists essentially only of Li O, B ZnO, and SiO.
  • FIG. 1 is a replica electron micrograph illustrating the cross-sectional microstructure of a conventional opal borosilicate glass
  • FIG. 2 is a replica electron micrograph depicting the cross-sectional microstructure of an opal borosilicate glass containing M00 made in accordance with the process described in application Ser. No. 94,834;
  • FIGS. 3-6 are replica electron micrographs demonstrating the cross-sectional microstructure of opal borosilicate glasses having compositions within the parameters of the instant invention.
  • FIGS. 7-11 are replica electron micrographs illustrattogether, will be converted to the desired oxide in the proper proportions.
  • the batch ingredients in Table I were melted in closed platinum crucibles at about l450- 1600 C. for about 16 hours.
  • the melt was poured onto a steel plate to form a patty about in diameter and in thickness.
  • No fining agent was employed but, where desired, conventional fining agents can be utilized.
  • the patty was immediately transferred to an annealer operating at about 650 C. Although the opal phase will generally strike in spontaneously as the melt is cooled to an amorphous solid, a denser opacity can be secured by heat treating the glass body at about 700-800 C. for about 5 minutes to one hour.
  • Table I also includes measurements of various physical properties (Softening Point, Annealing Point, Strain Point, Expansion, and Density) secured on the opalized bodies; these determinations being understaken according to conventional procedures.
  • the coefllcients of thermal expansion lO C. were measured over the range 0- 300" C.
  • opal borosilicate glass articles exhibiting a very bright white appearance and greatly improved chemical durability, particularly with respect to resistance to detergent attack, can be secured through the spontaneous opalization and/or the subsequent heat treatment of glass bodies consisting essentially, by weight on the oxide basis, of 0.5-2.5% L120, 7l0% ZnO, 11-14% B 0 and 71-76% SiO Electron microscopy studies of the interior of these articles have shown the opacifying phase to be present as separate droplets, essentially spherical in shape, with little or no interconnection. That these ranges of components are critical to the operability of the invention is visually confirmed in a comparison of FIGS. 3-6 With FIGS.
  • Table I records several examples of glasses falling within and without the compositional parameters of the instant invention in weight percent on the oxide basis.
  • the batch ingredients may comprise any materials, either the oxides or other compounds which, on being melted
  • FIGS. 1-11 are electron micrographs of Examples 1-11, respectively. (The white bar at the base of each photograph represents one micron.)
  • a study of these photographs clearly illustrates the substantial efiect which minor compositional changes have upon the configuration of the separated opal phase.
  • Example 1 a conventional borosilicate opal glass of commerce, assumes a continuous type of structure, i.e., the droplets are interconnected.
  • the articles shown in FIGS. 2-6 contain the precipitated phase as very small, spherically-shaped droplets.
  • Example 2 includes the surface tension agent M00 required in the above-discussed patent application, whereas Examples 3-6 fall within the compositional limitations of the instant invention.
  • Examples 3-6 clearly indicate that the presence of such surface tension agents is not required to achieve the development of the opal phase in discontinuous droplets (less than 0.5 micron in diameter) where the composition of the glass is included within the narrow parameters of the present invention.
  • FIGS. 7-11 dramatically demonstrate the extreme criticality of the outlined compositional variables of the instant invention. Hence, even very minor excursions outside of the reported U 0 and B 0 ranges produce the opal phase as interconnected rather than discontinuous droplets.
  • the glass is categorized AA. If removable with a water soaked cloth, the glass is classed A. Where a cloth soaked in detergent solution will remove the stain, the glass is graded B. If the stain can only be removed by rubbing with a cleansing powder, the glass is given a C rating and, where unremovable, the glass is classed F.
  • Table 11 illustrates the correlation between chemical durability and the presence of the separated phase as very small, discontinuous droplets.
  • Examples 2-6 exhibit at least a class A stain after 16 hours of immersion in the detergent solution whereas Examples 1 and 7-11 fail after 2-8 hours.
  • Examples 3-6 demonstrate chemical durability paralleling that exhibited by Example 2 containing M This factor unequivocally shows that within the stringent compositional limitations imposed here, a product can be manufactured having detergent durability essentially on a par with the products of the above-described application containing M00 W0 and AS203.
  • Example 4h0urs Shours compositions to aid melting and forming, to improve chemical durability, to inhibit unwanted devitrification, or to modify some other physical property but the total of all such inclusions must not exceed about 5% by weight, since a fine balance is drawn between the various components to insure the development of a discontinuous opal phase in very small spherically-shaped droplets.
  • Na O is preferably absent from the composition although up to about 0.5% by weight can be tolerated.
  • K 0 appears to aid durability but its inclusion in amounts greater than about 3% by weight tends to inhibit opalization, requiring extended secondary heat treatment of the glass to secure a dense opacity.
  • A1 0 improves durability but quantities in excess of about 1.5% appear to have an adverse effect upon opalization.
  • Examples 4 and 5 exhibiting the best resistance to detergent, reflect the preferred composition ranges of the invention, viz, 1-2% Li O, 89% ZnO, 12-13% B 0 and 73.5-% SiO We claim:
  • a borosilicate opal glass exhibiting a very bright white appearance with excellent resistance to detergents wherein the opal phase is present as discontinuous, spherically-shaped droplets, said glass consisting essentially by weight on the oxide basis, of about 0.5-2.5 Li O, 7-10% ZnO, 11-14% B 0 and 71-76% SiO the total of Li O, ZnO, B 0 and SiO constituting at least by weight of the composition, and 0-0.5 Na O, 03% K 0, and 01.5% A1 0 2.

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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)
US00141765A 1971-05-10 1971-05-10 Borosilicate opal glasses Expired - Lifetime US3723144A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US14176571A 1971-05-10 1971-05-10

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US3723144A true US3723144A (en) 1973-03-27

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Country Status (7)

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US (1) US3723144A (cs)
BE (1) BE780948A (cs)
CS (1) CS183631B2 (cs)
DE (1) DE2220302A1 (cs)
FR (1) FR2137524A1 (cs)
GB (1) GB1388603A (cs)
IT (1) IT955335B (cs)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4376170A (en) * 1982-03-22 1983-03-08 Corning Glass Works Zinc borosilicate opal glasses
US5591683A (en) * 1995-11-28 1997-01-07 Corning Incorporated Phase-separated, non-crystalline opal glasses
US20040063032A1 (en) * 1998-06-29 2004-04-01 Hiroki Yamamoto Optical information recording medium
US10232574B2 (en) 2014-12-17 2019-03-19 Novartis Ag Reusable lens molds and methods of use thereof

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4376170A (en) * 1982-03-22 1983-03-08 Corning Glass Works Zinc borosilicate opal glasses
US5591683A (en) * 1995-11-28 1997-01-07 Corning Incorporated Phase-separated, non-crystalline opal glasses
US20040063032A1 (en) * 1998-06-29 2004-04-01 Hiroki Yamamoto Optical information recording medium
US7169334B2 (en) * 1998-06-29 2007-01-30 Hitachi, Ltd. Optical information recording medium
US10232574B2 (en) 2014-12-17 2019-03-19 Novartis Ag Reusable lens molds and methods of use thereof

Also Published As

Publication number Publication date
BE780948A (fr) 1972-09-20
GB1388603A (en) 1975-03-26
CS183631B2 (en) 1978-07-31
FR2137524A1 (cs) 1972-12-29
DE2220302A1 (de) 1972-12-28
IT955335B (it) 1973-09-29

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