CZ2009446A3 - Ruby glass dyed with gold - Google Patents

Abstract

Gold-colored ruby glass, based on a crystal glass containing no lead and barium compounds, contains in weight. %: 68.0. + -. 2.5 SiO 2, 1.0, + -. 1.0 Al.sub.2 O.sub.3 and / or 1.0. + -. 1.0 B.sub.2 O.sub.3, 3.0 +. 2.5 L.sub.2.n.sub.3, 3.0 +. 2.0 SrO, 7.0. + -. 2.0 CaO, 1.0. + -. 1.0 MgO, 2.0. + -. 2.0 ZnO, 8.0. + -. 2.0 Na.sub.2 O, 10.0 +. 2.0 K.sub.2.n.O, 0.4 +. 0.2 wt.%, The sum of Al.sub.2 O.sub.3 and Ba.sub.2 O.sub.3 is up to 4 wt. %, the sum of K.sub.2 O and ZnO is greater than 10 wt. %, and the sum of La.sub.2.sub.2, SrO and CaO is greater than 12 wt. %, and further comprises above 100 wt. % of the aforementioned components, the addition of a color composition, in wt. % 0.05. + -. 0.03 Au, 0.06. + -. 0.04 Se, 1.00. + -. 1,00 SnO.sub.2.n ..

Description

Technical field

The invention relates to a gold-colored ruby glass based on lead-and-barium-free glass 5 having a refractive index greater than 1.52 and a density of at least 2.52 g.cm &^lt; ³ & gt ^; . Gold-colored ruby glass with a typical red tint is intended primarily for the production of hand-shaped, high-quality utility glass melted in gas and electric melters.

BACKGROUND OF THE INVENTION

The production of gold-colored ruby glass, the so-called "gold ruby" on an industrial scale, is still one of the most demanding glass technology processes. Featuring a unique deep red color, which is virtually not substitutable by the addition of another ingredient, this glass has for centuries retained the character of great uniqueness and mystery, which, among other things, showed itself by strictly concealing technological processes. A well-known historical example is the person of Johann Kunckel (1630 - 1705), who was apparently the first glass technologist to successfully produce a “golden ruby”. However, the production showed large losses and the price of glass was therefore high. After Kunckel's death, the technology of production was forgotten and rediscovered only in the second half of the 19th century with the fundamental contribution of modern scientific approaches to the principles of coloring substances with metal suspensions (Faraday M .: Phil. Mag. 14, 401, 5012 (1857)). experiments investigating the effect of glass composition on the color of the “golden ruby” (eg Muller W. (1871), see Weyl WA; Colored Glasses, p. 384, Society of Glass Technology, London 1999).

The patent literature is also very scarce for the preparation of gold ruby. Only GB X 5242 of 902 "Process for making gold-ruby glass for pressed, blown and cast products" is available. The author is Richard Zsigmondy from Jena. The claimed glass contains an addition of 0.25 to 1.7 parts of gold, for each 10000 parts of glass sand, while the charge for this gold ruby contains glass sand, soda and barium compounds - carbonates or nitrates. In the examples, the composition of the following raw materials for the oxide-based charge in parts:

30 1.66 SiO ₂ 0.288 Na ₂ O 0.276 BaO.

The Na ₂ O and BaO contents are almost identical, the amount of BaO is relatively high. From today's point of view, this glass is disadvantageous both ecologically and technologically.

31. The desired color scheme is given by the "gold ruby" of the nanocrystals of gold homogeneously dispersed in the glass, which very strongly absorb the green fraction of visible light (absorption maximum around 530 nm). The technology of starting the red color and its resulting shade are strongly dependent mainly on the solubility of metallic gold in the molten glass, which at temperatures above 1400 ° C reaches hundredths of a weight percent in the form of a true solution. During cooling, nuclides are first formed in the molten gold glass, the formation of which is usually facilitated by the addition of a so-called nucleating agent. Selenium, silver, antimony or bismuth compounds are usually used as nucleating agents. Subsequent growth of the nuclei creates gold crystals manifesting in the temperature range below 900 ° C by the development of the desired ruby color. In glass practice this process is called start-up.

The color development and the resulting color of the gold ruby strongly depend on the nucleation process and the rate of growth of the gold crystals. From this point of view, the optimum crystal size is between 10 and 50 nm. At a smaller size, the color shade is not intense enough and the glass is pink in color. When crystals greater than 100 nm are formed, which can be formed due to their rapid or long-term growth, or by coagulation during recrystallization, a brown, almost opaque coloration can be observed upon reflection of incident light. A thin layer of such glass shows a violet to blue color as light passes. This color effect vz] use so-called 5 _b. Safírinová glass. However, in the production of gold ruby, the size of gold crystals above 100 nm is undesirable. This suggests that the preparation of high-quality gold ruby is strongly dependent on the composition of the base crystal glass, which determines the solubility of gold in the melt and the temperature regime of melting, processing and cooling products.

Intense shades of gold ruby are usually obtained with high-lead glasses 2 (also containing larger amounts of potassium oxide). The reason for the high quality of the ruby lead glasses is primarily the higher solubility of gold compared to other glasses.

Soda-lime-silica glasses dissolve gold to a much lesser extent and the resulting ruby shade is usually of low intensity. The solubility of gold in these glasses can be increased by the addition of some chemical compounds, especially tin oxide. However, the preparation of gold ruby in lead-free glasses requires an optimal combination of coloring components and a more careful technological melting mode.

So far, gold rubies are in most cases prepared from glasses containing lead compounds. However, the lead content of the glasses is currently considered environmentally and hygienically unsuitable. In addition, lead glass manufacturers have to pay increasingly greater effort and cost to meet demanding environmental requirements for their own production, both in terms of emissions and treatment from the point of view of waste when grinding and polishing products. In addition, lead ruby glasses containing lead compounds usually do not start up when the temperature drops during molding.

In order to produce the color shade of the prior art gold-colored ruby glasses, an additional heat treatment, i.e., so-called start-up, which significantly increases the time and economic costs of production is usually necessary. In addition, high operational losses often occur during start-up due to the low reproducibility of this process.

The aim of the present invention is to design a composition of crystal glass with a color shade of "golden ruby" free of lead and barium compounds, capable of further refining, grinding and engraving and surface treatments that will meet demanding hygienic and ecological requirements. This glass, produced mainly in gas melting plants and shaped mainly by hand, has favorable technological and utility properties and is intended for table, beverage and utility use.

JO The essence of the technograss - - -

The disadvantages of the prior art are reduced or eliminated with gold-colored ruby glass according to the present invention, which is based on crystal glass, not containing! lead and barium compounds, in which the desired noble color of the "golden ruby" is achieved by the addition of gold and other chemicals. The essence of this technical solution is ruby glass, containing in wt.

68.0 ± 2.5 SiO ₂ 1.0 ± 1.0 Al ₂ O ₃ and / or 1.0 ± 1.0 B ₂ O _; 3.0 ± 2.5 La ₂ O ₃ 3.0 ± 2.0 SrO 7.0 ± 2.0 CaO 1.0 ± 1.0 MgO 2.0 ± 2.0 ZnO 8.0 ± 2.0 Na ₂ O 10.0 ± 2.0 K ₂ O 0.4 ± 0.2 Sb ₂ O ₃

the sum of Al ₂ O ₃ and B ₂ O ₃ is up to 4% by weight, the sum of K ₂ O and ZnO is higher than 10% by weight. and the sum of La ₂ O ₃ , SrO and CaO is greater than 12 wt.

The glass further comprises the addition of a coloring composition above 100% by weight, of the aforementioned components, 30. % in wt.

0.05 ± 0.03 Au,

0.06 ± 0.04 Se a

1.00 ± 1.00 SnO ₂ .

The main advantage of this invention is the achievement of the desired deeply colored ruby shade of optimum composition, in the normal course of manual glass processing without the need for additional heat treatment, the so-called start-up, which is usually necessary for ruby glasses containing lead compounds. The obtained ruby glass shows high stability and reproducibility of the ruby shade in the manual processing of shape-complicated products with repeated decreases and increases in temperature. The ruby glass of the composition mentioned in this technical solution can be applied directly by hand scooping from the pans or subsequently using prepared rods, so-called cones shaped from melted 3 ruby glass.

The refractive index of the ruby glass according to this invention is higher than 1.52, the specific gravity of the glass exceeds 2.52 g.cm &^lt; ³ & gt ^; . The coefficient of linear thermal expansion and 2o-3o ^ c is in the range of 9.5 ± 1.0 x W ® K ^-1 . The glass has increased chemical resistance of the product surface and thus meets the requirements for washing glass with alkaline detergents. It is very advantageous to use the same composition of the ruby glass overlay and / or underlay with the base crystal glass when receiving and underlaying the glass, which allows problem-free bonding of the ruby and crystal glass in one product, reduces unwanted stresses between these glasses, and mixtures. The favorable formability and workability of the basic crystal glass is also maintained.

15, Glass is suitable for melting in gas and electric melting equipment. The defined composition ranges allow the use of finishing techniques, eg engraving, grinding, metal decorative coatings, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

20 j _e described below in detail on embodiments of ruby glass colored gold, explained in the drawings, from which FIG. 1 shows the absorption spectra of the exemplary embodiment four ruby glass, where the horizontal axis the wavelength λ in nanometers, the vertical axis indicates the absorbance A glass, (

fig. 2 color coordinates Lab according to ČSN 011718 ruby glass according to example 1, fig. 3 color coordinates Lab according to ČSN 011718 ruby glass according to example 2, fig. 4 color coordinates Lab according to ČSN 011718 ruby glass according to example 3 and fig. Lab according to ČSN 011718 ruby glass according to example 4.

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Examples of technical solution

The designs of glass compositions were based primarily on the requirement of their high optical properties, characterized mainly by a refractive index value higher than 1.52. The choice of coloring components and the amount of their addition to the glass also had to satisfy the requirement of the ruby shade stability under normal operating conditions of manual processing of complex shaped products, with repeated decreases and increases in temperature.

35. The efficiency of the fining process was evaluated for exemplary glass compositions, which must be sufficiently high even when the maximum melting temperatures are required. The course of refining of the proposed glass was monitored under laboratory conditions as well as during experimental operating heats. The efficiency of this process was evaluated by laboratory measurement of the so-called average bubble growth rate at melting temperatures.

The color scheme of the glasses was objectively measured according to ČSN 011718 "Color measurement". From the cooled samples of laboratory and operational melted glasses, 5 polished plates of 2.0 mm thickness were prepared on both sides. Glass permeability spectra measured in the wavelength range 350 to 1100 nm. Calculation of color coordinates in the Lab colorimetric system proceeded procedure referred to in the above mentioned standard for standard light type C and a viewing angle ^of 10.

A large number of experimental melts were carried out with various additions of coloring agents IQ in laboratory and pilot scale. The extent of composition stated in the claims of this technical solution was determined on the basis of optimization of technological and utility properties of glass.

Table 1 shows the chemical composition of the base crystal glass used in the exemplary embodiments of ruby glasses. The selected properties of this 15 crystal glass are shown in Table 2.

Table 1 - Chemical composition of basic crystal glass in% by weight:

SiO2 AI2O3 B2O3 LajOa CaO SrO ZnO MgO K ₂ O Na _z O Sb ₂ O ₃ 67.19 0.16 0.73 1.96 7.33 3.91 0.98 0.05 10.16 7.06 0.47

Table 2 - Characteristics of basic crystal glass composition according to Table 1

Temperature (° C) for decimal logarithm (2; 5; 7,65) ’viscosity (dPa.s) Hydrolyt. resistance (ml 0.01 M HCI.g- ¹ ) "20-300" C (10 ® K ' ¹ ) Refractive index Specific gravity (g.cm ' ³ ) 2 5 7.65 1415 906 717 0.82 9.1 1,528 2,556

The temperatures given in Table 2 are assigned to the values of the decimal logarithms of the viscosities

2-5 where the viscosities are given in dPa.s. These values characterize the viscosity curves of the glass, where a viscosity log of 2 corresponds to a maximum melting temperature of 1415 ° C, and the logarithms 5 and 7.65 characterize the boundaries of the manual glass processing temperature range of 717 to 906 °. C. The transformation temperature of the exemplary glass is 528 ° C.

Hydrolytic resistance of glass expressed as consumption of 0.01 M HCl per 1 gram of glass pulp classifies exemplary glasses according to ČSN ISO 719 at the interface of water resistance class 3 and 4.

Average coefficient of thermal expansion and _{20th 300} »c, in the embodiments above the glass moves 10® 9 × K ^-1, which is required for the combination of the basic crystal stained glass, applied in the manufacture in the form of frits or přetahových cones or flashed or podjímaného glass.

Table 3 lists coloring agent additions and color coordinates (according to ČSN 011 718 "Color measurement") of four exemplary gold-colored ruby glasses. In all cases, the same gold addition of 0.025 wt.%, Above 100 wt.%, Was used. basic components.

Table 3 - Colorant additions in% wt. to the basic crystal glass for exemplary designs of ruby glasses and color coordinates according to ČSN 011 718

Example Ouch Se SnO ₂ Color coordinates L and b 1 0,025 0.05 1.00 51.72 61.23 12.86 2 0,025 0.05 0 52.07 56.11 7.25 3 0,025 0.02 1.00 60.15 52.88 15.77 4 0,025 0.02 0 62.84 46.83 5.15

2Q

The respective absorption spectra and the position of the resulting glass colors in the colorimetric space are shown in Figures 1 * 5.

The absorption spectrum in Figure 1 shows a graph showing the wavelength range λ in nanometers on the horizontal axis, and absorbance A on the vertical axis.

2 $ Measured absorbance values are used to calculate color coordinates

L, a, b according to ČSN 011718 "Color measurement". The color coordinates L, a, b according to ČSN 011718 "Color measurement", given in Table 3 for four exemplary gold colored ruby glasses are shown in Fig. 2 τ 5. These color coordinates L, a, b according to ČSN 011 718 "Measurement" are shown for gold colored ruby glass for Example 1 in Fig. 2, for Example 2 in Fig. 3, for Example 3 in Fig. 4 and for Example 4 in Fig. 5.

The shapes of the absorption spectra in Figure 1 make it possible indirectly to assess the hue and saturation of the hue depending on the number and size of the gold crystals in the ruby glasses. Relatively sharp absorption maxima in close proximity to the desired wavelength of 530 nm (Weyl NA .: Colored Glasses, Society of Glass Technology, London 1999) show a preferred mean gold crystal size in the range of 5 to 10 nm for a color shade of 35. The small width of the absorption maximum demonstrates a sufficient monodisperse gold crystal size distribution.

I ·

Higher peaks with absorbance values above 2 in Examples 1 and 2 confirm a sufficient value of the number of gold crystals per unit of glass volume.

This conclusion is also confirmed by the lower values of the color coordinate L in Table 3 and in Figures 2 and 3. The amount of absorption maxima in exemplary embodiments 3 and 4 in the range of 5 absorbances of 1.6 to 1.7 indicates less gold crystals per unit volume of glass, resulting in lower saturation of the ruby shade. This is also evidenced by the higher L-coordinate values in Table 3 and in Figures 4 and 5.

These conclusions make it possible to evaluate the effect of the addition of selenium and tin oxide. Selenium primarily plays the role of nucleating agent and the amount of its addition is influenced in particular by the number t0. of formed gold crystals in a unit of glass volume. Tin oxide is believed to increase the solubility of gold in the molten glass at maximum melting temperatures. The higher slope of the temperature dependence of the solubility of gold in the molten glass then accelerates the crystallization process with a subsequent decrease in temperature. However, the absorption spectra in Figure 1 show that this effect on the resulting ruby shade is relatively small.

With regard to the realization of the ruby glass according to this technical solution, it is not possible to explain the examples in a limited way. Gold colored ruby glass according to this technical solution can be successfully realized within the scope of the claims of the basic crystal glass, which is itself subject of the invention CZ PV 2009 - 445 and the corresponding utility model CZ UV No. 19 985, priority 9.7.2009 on the title „Crystal glass 2 (5 free of lead and barium compounds), of the same Applicant and of the same inventor as the present invention It is equally possible to successfully apply the addition concentrations of the gold-dye composition within the scope of the claims of this invention.

2S

Industrial applicability

Ruby glass colored gold, t _x vol. “Gold ruby”, free of lead and barium compounds, is intended for high quality table, commercial and beverage glasses. It is particularly suitable for bonding with crystal glasses by the so-called acceptance and underlay technique, in which a thin layer of ruby glass is applied to the crystal glass product from the outside or inside.

Claims (3)

OGHRAN-IF CLAIMS 1. Gold-colored ruby glass based on lead-barium-free crystal glass having a refractive index greater than 1.52 and a specific gravity of at least 2.52 g.cm &^lt; ^{-3 &gt};. Particularly suitable for the manual production of high-quality table top glass produced in gas and electric melters, characterized in that it contains by weight: 65.5 to 70.5 SiO _{2 2} to 2.0 Al ₂ O ₃ and / or up to 2.0 B ₂ O ₃ 0.5 to 5.5 La ₂ O ₃ 1.0 to 5,0 SrO 5.0 to 9.0 CaO to 2,0 MgO 6.0 to 10.0 Na ₂ O 8.0 to 12.0 K ₂ O 0.2 to 0.6 Sb ₂ O ₃ and further may contain up to 4.0 wt. ZnO, wherein the sum of Al ₂ O ₃ and B ₂ O ₃ is up to 4 wt%, the sum of K ₂ O and ZnO is greater than 10 wt%, and 20, the sum of La ₂ O ₃ , SrO and CaO is greater than 12 wt%, and that the ruby glass further comprises, above 100 wt%. % of the aforementioned components; 0.02 to 0.08 Au, 0.02 to 0.10 Se, % And further may contain up to 2 wt. SnO ₂ . Ruby glass according to claim 1, characterized in that it contains in% by weight: 67.19 SiO ₂ 0.16 ai ₂ o ₃ 1.96 La ₂ O ₃ 0.73 B ₂ O ₃ 3.91 SrO 7.33 CaO 0.05 MgO 0.98 ZnO 7.06 Na ₂ O 10.16 K ₂ O 0.47 Sb ₂ O ₃ and further comprising, above 100 wt.%, The addition of the color composition of the above components, in wt.% 0.025 Au 5 0.02 to 0.05 Se and up to 1.00 SnO ₂ and this glass has the following characteristics: temperature 1415 ° C for decadic logarithm of viscosity (dPa.s) = 2; temperature 906 ° C for decimal logarithm of viscosity (dPa.s) = 5; 10 ° C for the decadic logarithm of the viscosity (dPa.s) = 7.65; hydrolytic resistance = 0.82 ml of 0.01 M HCl per gram of grist; coefficient of mean linear thermal expansion and _2O . _3O ° C = 9.1 * 10 ^-6 K ^-1; refractive index = 1.528; specific gravity = 2,556 g.cmA