Glass composition

Abstract

Embodiments relate to a glass composition which can allow for realizing beautiful bluish green colors therein even upon the use of a trace amount of a colorant such as Ti, Co, and Cr, securing high visible light transmittance suitable for window glass, and effectively reducing transmittance of solar heat radiation to help reduce a cooling load in buildings and vehicles.

Claims

1. A soda-lime-silica glass composition comprising 65 to 75 wt % of SiO.sub.2, 0.3 to 3.0 wt % of Al.sub.2O.sub.3, 10 to 18 wt % of Na.sub.2O and K.sub.2O, 5 to 15 wt % of CaO, 1 to 7 wt % of MgO, and 0.5 to 1 wt % of a colorant, based on 100 wt % of the glass composition, the colorant comprising 100 parts by weight of Fe.sub.2O.sub.3, 0.01 to 0.2 parts by weight of Cr.sub.2O.sub.3, and at least one compound selected from the group consisting of 1 to 20 parts by weight of TiO.sub.2 and 0.01 to 0.2 parts by weight of CoO, wherein the glass composition has 0.5 to 0.69 wt% Fe.sub.2O.sub.3 based on 100 wt% of the glass composition, and a glass manufactured using the glass composition shows, on the basis of the thickness of the glass of 4 mm, optical properties including visible light transmittance (Tvis.) of 75% or more, and solar heat radiation transmittance (Tds.) of 56% or less.

2. The glass composition according to claim 1, wherein the glass composition comprises Fe.sub.2O.sub.3 in an amount of 0.57 to 0.69 wt %.

3. The glass composition according to claim 1, wherein Fe.sub.2O.sub.3 has an oxidation-reduction ratio of 0.15 to 0.35.

4. The glass composition according to claim 1, wherein Fe.sub.2O.sub.3 has an oxidation-reduction ratio of 0.2 to 0.3.

5. The glass composition according to claim 1, wherein the colorant comprises TiO.sub.2.

6. The glass composition according to claim 1, wherein the colorant comprises 6 to 10 parts by weight of TiO.sub.2 based on 100 parts by weight of Fe.sub.2O.sub.3.

7. The glass composition according to claim 1, wherein the colorant comprises CoO.

8. The glass composition according to claim 1, wherein the colorant comprises 0.04 to 0.15 parts by weight of CoO based on 100 parts by weight of Fe.sub.2O.sub.3.

9. The glass composition according to claim 1, wherein the colorant comprises 0.04 to 0.15 parts by weight of Cr.sub.2O.sub.3 based on 100 parts by weight of Fe.sub.2O.sub.3.

10. The glass composition according to claim 1, wherein the composition comprises, based on wt% of a mother glass composition, 71.0% of SiO.sub.2, 1.3% of Al.sub.2O.sub.3, 9.8% of CaO, 3.8% of MgO, 13.9% of Na.sub.2O, 0.15% of K.sub.2O, and 0.2% of SO.sub.3, the mother glass composition excluding a colorant in the glass composition.

11. The glass composition according to claim 1, wherein a glass manufactured using the glass composition shows a main wavelength (Dw.) of 493 nm to 503 nm, and excitation purity (Pe.) of 0.5 to 7%.

Description

EXAMPLES

(1) The glass melts described in all examples and comparative examples were prepared according to the procedure as follows.

(2) In manufacturing a glass melt, components were weighed and mixed in a mixer.

(3) As raw materials, silica, feldspar, lime stone, dolomite, soda ash, sodium sulfate and iron oxide were used, and glass batches of which mixing ratios were controlled to obtain target compositions referred in the examples and the comparative examples below, were molten using a gas furnace or an electrical furnace. A soda lime glass composition constituted of 71.0% of SiO.sub.2, 1.3% of Al.sub.2O.sub.3, 9.8% of CaO, 3.8% of MgO, 13.9% of Na.sub.2O, 0.15% of K.sub.2O and 0.2% of SO.sub.3, based on the wt % of a mother glass composition excluding a colorant in the glass composition, was used.

(4) 500 g of the weighed mixture was put in a 90% platinum/10% rhodium crucible, and molten in a gas furnace at 1450° C. for 1 hour and then rapidly cooled to recover a glass powder. After that, melting in an electrical furnace at 1450° C. for 1 hour was repeated twice to manufacture a sample with improved homogeneity. In addition, a sample for measuring the number of remaining bubbles, i.e., for evaluating melting quality was manufactured using a cylindrical alumina crucible having a diameter of 5 cm and a height of 10 cm, by weighing, based on 500 g, the same batch as the sample manufactured for the chemical component analysis and optical property evaluation of the glass composition, and melting the same in a gas furnace for 3 hours.

(5) Based on 100 wt % of the mother glass composition, the amounts of the colorant referred in the examples and the comparative examples were added, the glasses thus manufactured were cast molded using a graphite plate, and sample glasses were processed into a thickness of 4 mm. The chemical components and spectroscopic properties of the glass composition were measured as follows.

(6) The chemical analysis of the glass composition was conducted using 3370 X-ray fluorescence measuring apparatus (XRF) of RIGAKU Co.

(7) Visible light transmittance was measured using HUNTER LAB by CIE 1931 Yxy/2 chromaticity diagram vision (light source A).

(8) Solar heat radiation transmittance was measured according to ISO 13837 regulation by using Perkin Elmer Lambda 950 spectrophotometer.

(9) The main wavelength and excitation purity were measured using HUNTER LAB colorimeter apparatus by CIE 1931 Yxy/2 chromaticity diagram vision (light source C).

(10) The amount of the colorant and the optical property values thus measured are listed in Table 2 and Table 3 below.

(11) TABLE-US-00002 TABLE 2 Example Division Component 1 2 3 4 5 6 7 8 Colorant Fe.sub.2O.sub.3 0.62 0.63 0.59 0.57 0.69 0.62 0.63 0.64 (wt %) TiO.sub.2 6.45 0 0 7.02 11.59 8.06 12.70 9.38 CoO 0 0.10 0 0 0.07 0.05 0 0 Cr.sub.2O.sub.3 0 0 0.13 0 0 0.06 0 0 Oxidation- FeO/ 0.27 0.27 0.27 0.27 0.27 0.28 0.30 0.22 reduction total ratio Fe.sub.2O.sub.3 Optical Tvis. 77.7 77.1 79.1 79.5 76.1 77.3 76.2 79.5 properties Tds. 53.3 52.4 54.5 54.9 50.9 52.4 50.6 54.9 Dw. 496.1 491.9 501.9 500.3 494.7 493.7 493.0 500.4 Pe. 3.1 4.4 2.2 2.4 4.4 3.8 4.1 2.4

(12) TABLE-US-00003 TABLE 3 Comparative Example Division Component 1 2 3 4 5 6 7 8 9 Colorant Fe.sub.2O.sub.3 0.46 0.73 0.75 0.58 0.62 0.69 0.67 0.66 0.74 (wt %) TiO.sub.2 10.87 0 26.67 8.62 0 43.48 5.97 6.06 6.76 CoO 0 0 0 0.26 0 0 0 0 0 Cr.sub.2O.sub.3 0 0 0 0 0.56 0 0 0 0 Oxidation- FeO/ 0.27 0.29 0.29 0.3 0.25 0.23 0.4 0.13 0.29 reduction total ratio Fe.sub.2O.sub.3 Optical Tvis. 82.3 73.9 73.3 76.6 78.9 78.8 68.7 83.8 73.7 properties Tds. 58.4 47.7 47 52.4 54.9 54.1 40.9 60.1 47.4 Dw. 529 489.9 491.7 489.3 521.4 526.6 486.8 539.8 490.3 Pe. 1.8 5.8 5 5.6 1.7 1.9 9.4 2.6 5.5

(13) The amount of Fe.sub.2O.sub.3 means wt % based on 100 wt % of the glass composition, and the amounts of TiO.sub.2, CoO and Cr.sub.2O.sub.3 mean parts by weight based on 100 parts by weight of Fe.sub.2O.sub.3.

(14) As known in Table 2, Examples 1 to 8, which are the glass products according to the present invention, were found to provide soda lime glass compositions with high visible light transmittance, low solar heat radiation transmittance and beautiful bluish green color.

(15) Particularly, Example 1 and Comparative Example 1 showed similar oxidation-reduction ratios, but Comparative Example 1 had lower total amount of Fe.sub.2O.sub.3 than the present invention. Accordingly, Example 1 showed lower solar heat radiation transmittance than Comparative Example 1, and had a main wavelength (Dw.) in a range of 493 nm to 503 nm.

(16) In addition, Examples 2, 6, 7 and 8 and Comparative Example 5 had similar total amount of Fe.sub.2O.sub.3, but Comparative Example 5 had excessive amount of Cr.sub.2O.sub.3 and developed green color with a high main wavelength range (>503 nm). On the contrary, Examples 2, 6, 7 and 8 had the amount of each colorant in the numerical range of the present invention and satisfied the main wavelength range of 493 nm to 503 nm.

(17) Examples 3 and 4 and Comparative Example 4 had similar total amount of Fe.sub.2O.sub.3, and Example 5 and Comparative Examples 6, 7 and 8 had similar total amount of Fe.sub.2O.sub.3. However, the CoO amount for Comparative Example 4, the TiO.sub.2 amount for Comparative Example 6, and the oxidation-reduction ratios for Comparative Examples 7 and 8 were deviated from the numerical ranges of the present invention. Accordingly, the main wavelength range was deviated from 493 nm to 503 nm.

(18) If examining each comparative example in particular, Comparative Examples 1 to 3 showed examples deviated from the amount range of Fe.sub.2O.sub.3 suggested in the present invention. Particularly, Comparative Example 1 corresponded to a case where the amount of Fe.sub.2O.sub.3 was excessively small and showed high solar heat radiation transmittance (>56%) and high main wavelength (>503 nm). In addition, Comparative examples 2 and 3 corresponded to cases where the amount of Fe.sub.2O.sub.3 was excessively large and thus, had low visible light transmittance (<75%) and low main wavelength (<493 nm).

(19) Comparative Example 4 corresponded to a case where the amount of CoO was excessively large, and thus, developed strong blue color and had a main wavelength in a low range (<493 nm). Comparative Examples 5 and 6 corresponded to cases where the amount of Cr.sub.2O.sub.3 or TiO.sub.2 was excessively large, and thus, developed strong green color and yellow color and had a main wavelength in a high range (>503 nm).

(20) Comparative Examples 7 and 8 were secured to have oxidation-reduction ratios (FeO/total Fe.sub.2O.sub.3) deviated from the suggested configuration of the present invention. Particularly, Comparative Example 7 corresponded to a case where the reduction ratio was excessively large, and thus, showed low visible light transmittance (<75%), a main wavelength in a low range (<493 nm), and excessive excitation purity (>7%). Comparative Example 8 corresponded to a case where the reduction ratio was excessively small, and thus, showed high solar heat radiation transmittance (>56%), and a main wavelength in a high range (>503 nm).