Composition for glass, alkaline-earth aluminosilicate glass, and preparation method and application thereof

Abstract

A composition for glass, alkaline earth aluminosilicate glass, and a preparation method therefor and applications thereof. Based on the total number of moles of each component and the counting of oxides, the composition contains 68-73 mol % of SiO.sub.2, 11.5-15 mol % of Al.sub.2O.sub.3, 2-6 mol % of MgO, 2.5-7.5 mol % of CaO, 0-3 mol % of SrO, 2-7 mol % of BaO, 0-4 mol % of ZnO and 0.05-1.5 mol % of TiO.sub.2. The glass has a high strain point, a high Young's modulus, a high specific modulus, a high Vickers hardness, high chemical stability, a high refractive index and high glass formation stability, and has a lower forming temperature, a lower melting temperature, a lower thermal expansion coefficient, a lower surface tension, a lower density, and low glass manufacturing difficulty.

Claims

1. A composition for glass comprising, based on the total number of moles of the components, on an oxide basis, 68-73 mol % SiO.sub.2, 11.5-15 mol % Al.sub.2O.sub.3, 2-6 mol % MgO, 2.5-7.5 mol % CaO, 0-3 mol % SrO, 2-7 mol % BaO, 0-4 mol % ZnO, and 0.05-1.5 mol % TiO.sub.2; Wherein based on the total number of moles of the components, the contents of the components calculated in mole percent in the composition meet I>0, wherein the I value is calculated with the following formula:
I=[SiO.sub.2−P.sub.1×Al.sub.2O.sub.3−P.sub.2×BaO−P.sub.3×(MgO+ZnO)−P.sub.4×(CaO+SrO)−P.sub.5×TiO.sub.2]×100, wherein P.sub.1=4, P.sub.2=−2, P.sub.3=3.5, P.sub.4=3, and P.sub.5=−25, SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, SrO, BaO, ZnO, and TiO.sub.2 represent the mole percent of the corresponding component in the overall composition respectively.

2. The composition of claim 1, wherein based on the total number of moles of the components, on an oxide basis, the content of ZnO is 0.4-3 mol %, the content of Al.sub.2O.sub.3 is 11.7-12.8 mol %, the content of SiO.sub.2 is 68-72.2 mol %, the content of MgO is 2.35-5 mol %, the content of CaO is 3.4-7.3 mol %, the content of SrO is 0-2.61 mol %, the content of BaO is 2.3-5.8 mol %, and the content of TiO.sub.2 is 0.05-1.2 mol %.

3. The composition of claim 1, further containing a fining agent; based on the total number of moles of the components, on an oxide basis, the content of the fining agent is 0.04-0.15 mol %.

4. The composition of claim 3, wherein the fining agent is at least one of sulfate, nitrate, stannic oxide, stannous oxide, chloride, and fluoride.

5. The composition of claim 1, wherein based on the total number of moles of the components, on an oxide basis, SiO.sub.2+Al.sub.2O.sub.3>80 mol %.

6. The composition of claim 1, wherein based on the total number of moles of the components, in mole percent, 0.8≥(MgO+BaO)/R′O≥0.34, wherein R′O=MgO+CaO+SrO+BaO+ZnO.

7. The composition of claim 6, wherein 0.7≥(MgO+BaO)/R′O≥0.5.

8. The composition of claim 1, wherein based on the total number of moles of the components, in mole percent, 0.6≤Al.sub.2O.sub.3/R′O≤1, wherein R′O=MgO+CaO+SrO+BaO+ZnO.

9. The composition of claim 8, wherein 0.7<Al.sub.2O.sub.3/R′O<0.8.

10. The composition of claim 1, wherein I is 0.5-50.

11. The composition of claim 10, wherein I is 2-13.5.

12. A method for preparing alkaline-earth aluminosilicate glass comprising treating the composition for glass of claim 1 by melting, forming, annealing, and machining sequentially.

13. Alkaline-earth aluminosilicate glass prepared with the method of claim 12, wherein the density of the alkaline-earth aluminosilicate glass is smaller than 2.67 g/cm.sup.3, the Young's modulus is greater than 75 GPa, the specific modulus is greater than 29 GPa/(g/cm.sup.3), and the refractivity nD is greater than 1.53.

14. The alkaline-earth aluminosilicate glass of claim 13, wherein the thermal expansion coefficient at 50-350° C. is smaller than 39×10.sup.−7/° C., the forming temperature T.sub.w corresponding to 35,000 P viscosity is lower than 1,320° C., the melting temperature T.sub.m corresponding to 200 P viscosity is lower than 1,650° C., the liquidus temperature T.sub.l is lower than 1,220° C., the strain point T.sub.st is 750° C. or above, and the annealing point T.sub.a is 790° C. or above.

15. The alkaline-earth aluminosilicate glass of claim 13, wherein the surface tension at 1,200° C. is smaller than 350 mN/m, the Vickers hardness is greater than 6.4 GPa, and the number of bubbles having bubble diameter>0.1 mm per Kg glass substrate is so low that the bubbles are invisible.

16. The alkaline-earth aluminosilicate glass of claim 13, wherein the glass formation stability factor D is smaller than 1.0, wherein the value D is calculated with the following formula:
D=(T.sub.l−T.sub.a)/(T.sub.m−T.sub.l), wherein T.sub.m, T.sub.l and T.sub.a respectively represent the melting temperature, liquidus temperature, and annealing point temperature of the glass corresponding to 200 P viscosity of the glass.

17. The alkaline-earth aluminosilicate glass of claim 16, wherein the glass formation stability factor D is 0.62-0.74.

18. A method for preparing a display device and/or solar cell comprising providing the composition for glass of claim 1.

19. The method of claim 18, further comprising apply the composition for glass as a glass substrate material and/or a glass film material for screen surface protection of flat panel display products, a glass substrate material and/or glass material for surface packaging and/or glass film material for screen surface protection of flexible display products, or a glass substrate material of flexible solar cells.

Description

DETAILED DESCRIPTION

(1) The ends points and any I valuen the ranges disclosed in the present invention are not limited to the exact ranges or values; instead, those ranges or values shall be comprehended as encompassing values that are close to those ranges or values. For numeric ranges, the end points of the ranges, the end points of the ranges and the discrete point values, and the discrete point values may be combined with each other to obtain one or more new numeric ranges, which shall be deemed as having been disclosed specifically in this document.

(2) In a first aspect, the present invention provide a composition for glass comprising, based on the total number of moles of the components, on an oxide basis, 68-73 mol % SiO.sub.2, 11.5-15 mol % Al.sub.2O.sub.3, 2-6 mol % MgO, 2.5-7.5 mol % CaO, 0-3 mol % SrO, 2-7 mol % BaO, 0-4 mol % ZnO, and 0.05-1.5 mol % TiO.sub.2.

(3) In the present invention, those skilled in the art should understand that “alkali-free” refers to that the composition for glass or the glass doesn't contain any alkali metal (i.e., any of the six alkali metal elements in the group IA in the periodic table of elements).

(4) In the composition according to the present invention, preferably, based on the total number of moles of the components, on an oxide basis, SiO.sub.2+Al.sub.2O.sub.3>80 mol %.

(5) In the composition according to the present invention, preferably, based on the total number of moles of the components, in mole percent, the contents of the components in the composition meet I>0, preferably is 0.5-50, further preferably is 0.59-33.85, even further preferably is 0.59-33.35, even more further preferably is 0.59-21.6, still further preferably is 2-13.5, optimally is 3.65-11.65, wherein the I value is calculated with the following formula:
I=[SiO.sub.2−P.sub.1×Al.sub.2O.sub.3−P.sub.2×BaO−P.sub.3×(MgO+ZnO)−P.sub.4×(CaO+SrO)−P.sub.5×TiO.sub.2]×100,

(6) Wherein P.sub.1=4, P.sub.2=−2, P.sub.3=3.5, P.sub.4=3, and P.sub.5=−25,

(7) SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, SrO, BaO, ZnO, and TiO.sub.2 represent the mole percent of the corresponding component in the overall composition respectively.

(8) In the composition according to the present invention, preferably, based on the total number of moles of the components, in mole percent, 0.8≥(MgO+BaO)/R′O≥0.34, further preferably 0.75≥(MgO+BaO)/R′O≥0.45, even further preferably 0.7≥(MgO+BaO)/R′O≥0.5, wherein R′O=MgO+CaO+SrO+BaO+ZnO.

(9) In the composition according to the present invention, preferably, based on the total number of moles of the components, in mole percent, 0.6≤Al.sub.2O.sub.3/R′O≤1; further preferably 0.65≤Al.sub.2O.sub.3/R′O≤0.95; even further preferably 0.7≤Al.sub.2O.sub.3/R′O≤0.85; still further preferably 0.7<Al.sub.2O.sub.3/R′O<0.8, wherein R′O=MgO+CaO+SrO+BaO+ZnO.

(10) In the present invention, SiO.sub.2 is a glass former. If the content of SiO.sub.2 is too low, it is disadvantageous for improving the resistance to chemical corrosion, the expansion coefficient will be too high, and devitrification may occur easily in the glass; increasing the content of SiO.sub.2 is helpful for reducing the weight of the glass, decreasing the thermal expansion coefficient, increasing the strain point, and improving the chemical resistance, but the high-temperature viscosity will be increased at the same time. The increased high-temperature viscosity is adverse to melting, and can't be handled in ordinary kilns or furnaces. Therefore, the content of SiO.sub.2 is determined as 68-73%. Hence, in comprehensive consideration, based on the total number of moles of the components, on an oxide basis, the content of SiO.sub.2 is 68-73 mol %, preferably is 68-72.2 mol %.

(11) In the present invention, Al.sub.2O.sub.3 is used to improve the strength of the glass structure. If the content of Al.sub.2O.sub.3 is lower than 11.5 mol %, it is difficult to improve the heat resistance of the glass, and the glass is susceptible to the erosion of environmental moisture and chemical reagents. Higher content of Al.sub.2O.sub.3 is helpful for increasing the strain point and mechanical strength of the glass. However, if the content of Al.sub.2O.sub.3 is too high, a devitrification phenomenon may occur in the glass, and it is difficult to melt the glass. Therefore, in comprehensive consideration, based on the total number of moles of the components, on an oxide basis, the content of Al.sub.2O.sub.3 is 11.5-15 mol %, preferably is 11.7-12.8 mol %.

(12) In the present invention, MgO greatly increase the Young's modulus and hardness of the glass, decrease the high-temperature viscosity of the glass, and makes glass melting easier. In a case that the content of alkaline earth metals in alkali-free silicate glass, a local accumulation effect may be created in the structure and the short-range order span can be increased by introducing network-modifying ions Mg.sup.2+ with high electric field intensity. In such a case, after a large quantity of intermediate oxide Al.sub.2O.sub.3 is introduced, the ions will exist in a state of [AlO.sub.4]; since these polyhedrons carry negative charges, some network modifying cations are attracted, and the accumulation degree and devitrification ability of the glass are decreased; in a case that the content of alkaline earth metals is high and the network breakage is severe, by introducing MgO, the broken silicon-oxygen tetrahedrons will be reconnected and the devitrification ability of the glass will be decreased. Therefore, attention shall be paid to the ratios of MgO to other components. Compared with other alkali-earth oxides, the existence of MgO leads to lower expansion coefficient and density, higher chemical resistance, higher strain point and higher elastic modulus. If the content of MgO is greater than 6 mol %, the chemical resistance of the glass will be degraded, and devitrification may occur easily in the glass; if the content of MgO is too low, it will be adverse to the improvement of the specific modulus. Therefore, in comprehensive consideration, based on the total number of moles of the components, on an oxide basis, the content of the MgO is 2-6 mol %, preferably is 2.35-5 mol %.

(13) In the present invention, CaO is used to promote glass melting and adjust glass forming. If the content of CaO is lower than 2.5 mol %, it is disadvantageous for decreasing the viscosity of the glass; if the content of CaO is too higher, devitrification may occur in the glass easily, and the thermal expansion coefficient will be increased significantly, adverse to the follow-up manufacturing procedures. Therefore, in comprehensive consideration, based on the total number of moles of the components, on an oxide basis, the content of CaO is 2.5-7.5 mol %, preferably is 3.4-7.3 mol %.

(14) In the present invention, SrO is used as a fusing agent and used to prevent devitrification in the glass. If the content of SrO is too high, the glass density will be excessively high, resulting in excessive density of the product. Therefore, based on the total number of moles of the components, on an oxide basis, the content of SrO is 0-3 mol %, preferably is 0-2.61 mol %.

(15) In the present invention, the role of BaO is similar to that of SrO. If the content of BaO is too high, the density of the glass will be increased excessively and the strain point will be decreased significantly. Therefore, based on the total number of moles of the components, on an oxide basis, the content of BaO is 2-7 mol %, preferably is 2.3-5.8 mol %.

(16) In the present invention, the divalent metal oxides may be categorized into two types, according to their positions in the periodic table of elements and influences on the properties: one type of divalent metal oxides consist of alkali-earth oxides in the main group, the ion R.sup.2+ of which has an eight outer electron structure; the other type of divalent metal oxides consist of metal oxides in the subgroups in the periodic table of elements (e.g., ZnO and CdO, etc.), the ion R.sup.2+ of which has an eighteen outer electron structure. The structural states of the two types of divalent metal oxides in the glass have different influences on the properties of the glass. ZnO can decrease the high-temperature viscosity of the glass (e.g., 1,500° C.), and is helpful for eliminating bubbles; in addition, it has effects such as improving the strength and hardness of the glass, improving the chemical resistance of the glass, and decreasing the thermal expansion coefficient of the glass, at temperatures below the softening point. Adding ZnO in a proper amount into an alkali-free glass system is helpful for inhibiting devitrification and decreasing devitrification temperature. Theoretically, after ZnO is introduced as a network modifying element into alkali-free glass, it usually exists in the form of [ZnO.sub.4] at high temperatures, and the glass structure is looser than a glass structure that contains [ZnO.sub.6]. Compared with ZnO-free glass in the same high temperature state, ZnO-containing glass has lower viscosity and higher atom movement speed. Therefore, crystal nuclei can't be formed in the ZnO-containing glass unless the temperature is decreased further. Therefore, ZnO decreases the upper limit of devitrification temperature in glass. If the content of ZnO is too high, the strain point of the glass will be decreased significantly. Therefore, in comprehensive consideration, based on the total number of moles of the components, on an oxide basis, the content of ZnO is 0-4 mol %, preferably is 0.4-3 mol %.

(17) In the present invention, TiO.sub.2 is used to promote glass melting and improve the stability of glass formation; in addition, the TiO.sub.2 can effectively increase the refractivity of the glass and decrease the expansion coefficient of the glass. If the content of TiO.sub.2 is excessively high, the above-mentioned effects will not be reduced significantly, and the stability of glass formation will be reduced. Therefore, in comprehensive consideration, based on the total number of moles of the components, on an oxide basis, the content of TiO.sub.2 is 0.05-1.5 mol %, preferably is 0.05-1.2 mol %.

(18) In the present invention, the composition further contains a fining agent, which preferably is at least one of sulfate, nitrate, stannic oxide, stannous oxide, chloride, and fluoride; wherein preferably stannous oxide SnO is added into the glass component as a fining agent or defrothing agent during glass melting, so as to improve glass melting. If the content of the fining agent is too high, devitrification may occur in the glass substrate. Therefore, preferably, based on the total number of moles of the components, on an oxide basis, the content of the fining agent is 0.04-0.15 mol %.

(19) Those skilled in the art should understand that “the composition for glass in the present invention contains SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, SrO, BaO, ZnO and TiO.sub.2” means the composition contains Si-containing compounds, Al-containing compounds, Mg-containing compounds, Ca-containing compounds, Sr-containing compounds, Ba-containing compounds, Zn-containing compounds, and Ti-containing compounds. For example, the composition for glass contains carbonate, nitrate, sulfate, phosphates, basic carbonates, and oxides, etc. of the aforesaid elements. In addition, the contents of the aforesaid components are measured in the oxides of the elements, respectively. The specific selections of the carbonates, nitrates, sulfates, phosphates, basic carbonates, and oxides of the elements are well known to those skilled in the art, and will not be further detailed here.

(20) When the composition for glass in the present invention is utilized to prepare alkaline-earth aluminosilicate glass, the obtained glass has excellent overall properties, mainly owing to the cooperation among the components, especially the cooperation among SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, SrO, BaO, ZnO, and TiO.sub.2, particularly the cooperation among the aforesaid components in specific contents.

(21) In a second aspect, the present invention provides alkaline-earth aluminosilicate glass comprising, based on the total number of moles of the components, 68-73 mol % SiO.sub.2, 11.5-15 mol % Al.sub.2O.sub.3, 2-6 mol % MgO, 2.5-7.5 mol % CaO, 0-3 mol % SrO, 2-7 mol % BaO, 0-4 mol % ZnO, and 0.05-1.5 mol % TiO.sub.2.

(22) Preferably, in the alkaline-earth aluminosilicate glass, SiO.sub.2+Al.sub.2O.sub.3>80 mol %.

(23) In the composition according to the present invention, preferably, based on the total number of moles of the components, in mole percent, the contents of the components in the composition meet I>0, further preferably is 0.5-50, even further preferably is 0.59-33.85, still further preferably is 0.59-21.6, still more further preferably is 2.07-13.29, wherein the I value is calculated with the following formula:
I=[SiO.sub.2−P.sub.1×Al.sub.2O.sub.3−P.sub.2×BaO−P.sub.3×(MgO+ZnO)−P.sub.4×(CaO+SrO)−P.sub.5×TiO.sub.2]×100,

(24) Wherein P.sub.1=4, P.sub.2=−2, P.sub.3=3.5, P.sub.4=3, and P.sub.5=−25,

(25) SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, SrO, BaO, ZnO, and TiO.sub.2 represent the mole percent of the corresponding component in the overall composition respectively.

(26) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, in mole percent, 0.8≥(MgO+BaO)/R′O≥0.34, further preferably 0.75≥(MgO+BaO)/R′O≥0.45, even further preferably 0.7≥(MgO+BaO)/R′O≥0.5, wherein R′O=MgO+CaO+SrO+BaO+ZnO.

(27) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, in mole percent, 0.6≤Al.sub.2O.sub.3/R′O≤1; further preferably 0.65≤Al.sub.2O.sub.3/R′O≤0.95; even further preferably 0.7≤Al.sub.2O.sub.3/R′O≤0.85; still further preferably 0.7≤A.sub.2O.sub.3/R′O<0.8, wherein R′O=MgO+CaO+SrO+BaO+ZnO.

(28) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, on an oxide basis, the content of ZnO is 0.4-3 mol %.

(29) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, on an oxide basis, the content of Al.sub.2O.sub.3 is 11.7-12.8 mol %.

(30) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, on an oxide basis, the content of SiO.sub.2 is 68-72.2 mol %.

(31) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, on an oxide basis, the content of MgO is 2.35-5 mol %.

(32) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, on an oxide basis, the content of CaO is 3.4-7.3 mol %.

(33) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, on an oxide basis, the content of SrO is 0-2.61 mol %.

(34) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, on an oxide basis, the content of BaO is 2.3-5.8 mol %.

(35) Preferably, in the alkaline-earth aluminosilicate glass, based on the total number of moles of the components, on an oxide basis, the content of TiO.sub.2 is 0.05-1.2 mol %.

(36) Preferably, in the alkaline-earth aluminosilicate glass, the content of the fining agent (preferably is stannous oxide) is 0.04-0.15 mol %.

(37) In a third aspect, the present invention provides a method for preparing alkaline-earth aluminosilicate glass comprising treating the composition for glass according to the present invention by melting, forming, annealing, and machining sequentially.

(38) The specific restrictions on the composition for glass in the method provided in the present invention have been described in the corresponding preceding text, and will not be further detailed here.

(39) In the method provided in the present invention, preferably, the conditions for melting treatment include: temperature: lower than 1,650° C.; time: longer than 1 h. Those skilled in the art can determine the specific melting temperature and melting time according to the actual circumstance. The specific melting temperature and melting time are well known to those skilled in the art, and will not be further detailed here.

(40) In the method provided in the present invention, preferably, the conditions for annealing treatment include: temperature: 790° C. or above; time: longer than 0.1 h. Those skilled in the art can determine the specific annealing temperature and annealing time according to the actual circumstance. The specific annealing temperature and annealing time are well known to those skilled in the art, and will not be further detailed here.

(41) In the method provided in the present invention, there is no particular restriction on the machining. In other words, the machining may be any common machining method in the art. For example, the product obtained through the annealing treatment may be cut, ground, and polished, etc.

(42) Specifically, in the preparation of the glass, first, the raw materials for the composition, which contain components in mole percent of oxides corresponding to the above-mentioned glass substrates, are mixed and stirred to a homogeneous state; then the mixed raw materials processed by melting, the bubbles are expelled and removed by stirring with a platinum rod, and the molten glass is homogenized; next, the temperature is decreased to a range required for glass substrate forming, and a glass substrate is produced in thickness required for flat panel display under an annealing principle; then the formed glass substrate is subject to simple cold-working treatment; finally, the basic physical properties of the glass substrate are tested; thus, an acceptable product is obtained.

(43) In a fourth aspect, the present invention provides alkaline-earth aluminosilicate glass prepared with the method described above.

(44) Preferably, the density of the alkaline-earth aluminosilicate glass according to the present invention is smaller than 2.67 g/cm.sup.3.

(45) Preferably, the Young's modulus of the alkaline-earth aluminosilicate glass is greater than 75 GPa.

(46) Preferably, the specific modulus of the alkaline-earth aluminosilicate glass is greater than 29 GPa/(g/cm.sup.3).

(47) Preferably, the thermal expansion coefficient of the alkaline-earth aluminosilicate glass at 50-350° C. is smaller than 39×10.sup.−7/° C.

(48) Preferably, the refractivity n.sub.D of the alkaline-earth aluminosilicate glass is greater than 1.53, further preferably is 1.534-1.545.

(49) Preferably, the forming temperature T.sub.w of the alkaline-earth aluminosilicate glass corresponding to 35,000 P viscosity is lower than 1,320° C.

(50) Preferably, the melting temperature T.sub.m of the alkaline-earth aluminosilicate glass corresponding to 200 P viscosity is lower than 1,650° C.

(51) Preferably, the liquidus temperature T.sub.l of the alkaline-earth aluminosilicate glass is lower than 1,220° C., further preferably is 1,120-1,180° C.

(52) Preferably, the strain point T.sub.st of the alkaline-earth aluminosilicate glass is 750° C. or above.

(53) Preferably, the annealing point T.sub.a of the alkaline-earth aluminosilicate glass is 790° C. or above.

(54) Preferably, the glass formation stability factor D of the alkaline-earth aluminosilicate glass is smaller than 1.0, further preferably is 0.5-0.95, even further preferably is 0.59-0.84, even more further preferably is 0.59-0.74, still further preferably is 0.62-0.74, wherein the value D is calculated with the following formula:
D=(T.sub.l−T.sub.a)/(T.sub.m−T.sub.l),

(55) Wherein T.sub.m, T.sub.l and T.sub.a respectively represent the melting temperature, liquidus temperature, and annealing point temperature of the glass corresponding to 200 P viscosity of the glass.

(56) Preferably, the surface tension of the alkaline-earth aluminosilicate glass at 1,200° C. is smaller than 350 mN/m.

(57) Preferably, the Vickers hardness of the alkaline-earth aluminosilicate glass is greater than 6.4 GPa.

(58) Preferably, the number of bubbles having bubble diameter>0.1 mm per Kg glass substrate is so low that the bubbles are invisible.

(59) In a fifth aspect, the present invention provides an application of the composition for glass or alkaline-earth aluminosilicate glass according to the present invention in preparation of a display device and/or solar cell, preferably an application in preparation of a glass substrate material and/or a glass film material for screen surface protection of flat panel display products, a glass substrate material and/or glass material for surface packaging and/or glass film material for screen surface protection of flexible display products, or a glass substrate material of flexible solar cells.

Embodiments

(60) Hereunder the present invention will be detailed in embodiments. In the following embodiments, unless otherwise specified, all of the materials are commercially available, and all of the methods are conventional methods in the art.

(61) In the following Examples and Comparative Examples, the density of glass is measured as per ASTM C-693, in unit of g/cm.sup.3.

(62) The thermal expansion coefficient of glass at 50-350° C. is measured with a horizontal dilatometer as per ASTM E-228, in unit of 10.sup.−7/° C.

(63) The Young's modulus of glass is measured with a material mechanical tester as per ASTM C-623, in unit of GPa.

(64) The Vickers hardness of glass is measured with a Vickers hardness tester as per ASTM E-384, in unit of GPa.

(65) The annealing point and strain point of glass are measured with an annealing point/strain point tester as per ASTM C-336, in unit of ° C.

(66) A viscosity-temperature curve of glass at high temperatures is measured with a rotary high-temperature viscosimeter as per ASTM C-965; wherein the melting temperature corresponding to 200 P viscosity is denoted as T.sub.m, in unit of ° C.; the forming temperature corresponding to 35,000 P viscosity is denoted as T.sub.w, in unit of ° C.

(67) The upper limit of devitrification temperature (liquidus temperature) of glass is measured through a temperature gradient furnace process as per ASTM C-829.

(68) The surface tension at 1,200° C. is measured with a high-temperature surface tensiometer, in unit of mN/m.

(69) The refractivity n.sub.D at 587.6 nm wavelength (sodium yellow laser) is measured at room temperature with a WAY-2S Abbe digital display refractometer.

(70) The number of bubbles having bubble diameter>0.1 mm per Kg glass substrate refers to the number of bubbles having bubble diameter>0.1 mm in every 1 Kg of alkaline-earth aluminosilicate glass substrate, and is measured with the following method: the weight of sample glass is measured with an electronic balance at 0.01 g accuracy, the quantity of bubbles is counted statistically under an optical microscope, and then the number of bubbles having bubble diameter>0.1 mm per Kg glass is calculated.

Example 1-14 and Comparative Examples 1-13

(71) The components are weighed as indicated in Tables 1-4 and mixed to a homogeneous state, the mixture is poured into a platinum crucible, then the crucible is heated in a resistance oven at 1,620° C. for 4 h, while the mixture is stirred with a platinum rod to expel the bubbles. The molten glass is poured into a stainless steel/cast iron mold and formed into glass product in a specified shape, then the glass product is annealed in an annealing furnace for 2 h, and then the power is turned off and the glass product is cooled in the furnace to 25° C. The glass product is cut, ground and polished, and then washed with deionized water and dried. Thus, a finished glass product meeting the testing requirements is produced. The properties of the glass product are tested respectively. The results are shown in Tables 1-4.

(72) TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 SiO.sub.2 68 70.4 70.9 71.7 72.2 70.8 68.5 Al.sub.2O.sub.3 12.8 12.3 12.1 12 11.7 12.55 14 SiO.sub.2 + Al.sub.2O.sub.3 80.8 82.7 83 83.7 83.9 83.35 82.5 MgO 4.46 5 3.1 3.3 4.6 2.35 3.6 CaO 5.9 3.6 7.3 6.4 5.75 3.4 3.9 SrO 0.4 0.8 2.61 0 0.3 1.3 0.7 BaO 5.8 4.4 2.3 3.4 4.9 5.7 4.8 ZnO 1.6 2.2 0.8 2 0.46 3.6 3.3 TiO.sub.2 1 1.2 0.8 1.1 0.05 0.2 1.1 SnO 0.04 0.1 0.09 0.1 0.04 0.1 0.1 R′O = MgO + 18.16 16 16.11 15.1 16.01 16.35 16.3 CaO + SrO + BaO + ZnO (MgO + BaO)/R′O 0.56 0.59 0.34 0.44 0.59 0.49 0.52 Al.sub.2O.sub.3/R′O 0.70 0.77 0.75 0.79 0.73 0.77 0.86 I value 13.29 21.6 3.72 20.25 0.59 2.075 11.65 density(g/cm.sup.3) 2.66 2.63 2.58 2.6 2.6 2.65 2.64 expansion coefficient 38.3 36.5 38.2 35.9 37.5 38.1 37.8 (×10.sup.−7/°7) Young's 79.6 79.2 79.3 77.6 78.7 78.8 79.5 modulus(GPa) specific modulus 29.9 30.1 30.7 29.8 30.3 29.6 30.1 (GPa/(g/cm.sup.3)) 1200° 2 surface 332.6 327.1 333.4 334.3 326.3 336.2 339.9 tension (mN/m) Vickers 6.67 6.88 6.83 7.14 6.93 6.86 6.89 hardness (GPa) number of bubbles 0 0 0 0 0 0 0 having bubble diameter >0.1 mm per Kg glass T.sub.m (° C.) 1601.6 1647.7 1617.3 1649.6 1647 1648.5 1631.8 T.sub.w (° C.) 1244 1283.6 1272.4 1284.1 1296 1296.5 1265.9 T.sub.l (° C.) 1140 1150 1160 1120 1160 1130 1210 annealing point 809 814.6 823.3 808.6 825.9 809.6 807.5 T.sub.a (° C.) strain point T.sub.st 761 766.1 775.9 765.2 778.6 762.4 764.3 (° C.) glass stability 0.72 0.67 0.74 0.59 0.69 0.62 0.95 factor D refractivity n.sub.D 1.534 1.537 1.542 1.538 1.537 1.543 1.538

(73) TABLE-US-00002 TABLE 2 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 SiO.sub.2 69.1 69.1 70.5 71.1 71.3 72.9 69.45 Al.sub.2O.sub.3 13.5 11.6 13.9 12.4 12.45 11.5 13.9 SiO.sub.2 + Al.sub.2O.sub.3 82.6 80.7 84.4 83.5 83.75 84.4 83.35 MgO 6 2.8 5.25 3.8 4 2.1 2.35 CaO 2.6 4.3 4 4.5 5.64 4.9 3.4 SrO 3 2.4 0.6 1.5 0.4 1.7 1.3 BaO 4.7 6.7 2.8 4.3 4.5 3.7 5.7 ZnO 0.3 2.5 1.4 0.9 0.7 1.8 3.6 TiO.sub.2 0.7 0.5 1.5 1.4 0.9 1.3 0.2 SnO 0.1 0.1 0.05 0.1 0.11 0.1 0.1 R′O = MgO + 16.6 18.7 14.05 15 15.24 14.2 16.35 CaO + SrO + BaO + ZnO (MgO + BaO)/R′O 0.64 0.51 0.57 0.54 0.56 0.41 0.49 Al.sub.2O.sub.3/R′O 0.81 0.62 0.99 0.83 0.82 0.81 0.85 I value 3.15 9.95 20.925 30.65 18.43 33.35 −4.675 density (g/cm.sup.3) 2.64 2.66 2.56 2.61 2.61 2.6 2.66 expansion coefficient 38.2 38.9 32.3 37.7 37.9 31.2 38.3 (×10.sup.−7/° C.) Young's 83.2 78.9 86.2 78.9 78.6 77.5 78.4 modulus(GPa) specific modulus 31.5 29.7 33.7 30.2 30.1 29.8 29.5 (GPa/(g/cm.sup.3)) 1200° C. surface 330.8 331.5 338.5 330.4 331.3 332 354.7 tension (mN/m) Vickers hardness 6.61 6.41 7.04 6.87 6.85 7.12 6.81 (GPa) number of bubbles 0 0 0 0 0 0 0 having bubble diameter >0.1 mm per Kg glass T.sub.m (° C.) 1619.7 1630.7 1622.1 1642.8 1646 1649.8 1642.9 T.sub.w (° C.) 1280.1 1253.9 1286 1286.5 1291.5 1304.8 1356.8 T.sub.l (° C.) 1170 1160 1180 1200 1190 1170 1270 annealing point 834 796.5 840.5 825.9 829.4 807.9 822.3 T.sub.a (° C.) strain point 786 764.7 792.5 778.9 783.4 769.6 755.4 T.sub.st(° C.) glass stability 0.75 0.77 0.77 0.84 0.79 0.75 1.20 factor D refractivity n.sub.D 1.532 1.540 1.531 1.532 1.536 1.535 1.536

(74) TABLE-US-00003 TABLE 3 Comparative Comparative Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 SiO.sub.2 68 68 68 68 71.7 69.25 69.8 Al.sub.2O.sub.3 10.8 12.8 12.8 15.8 12.5 14.1 14.8 SiO.sub.2 + Al.sub.2O.sub.3 78.8 80.8 80.8 83.8 84.2 83.35 84.6 MgO 4.46 4.46 4.46 3.46 3.0 4.2 4.3 CaO 6.9 5.9 5.9 4.9 4.2 5.3 4.6 SrO 1.4 1.4 5.8 0.4 1.6 2.6 0.7 BaO 5.8 5.8 0.4 4.8 2.9 1.8 5.3 ZnO 1.6 1.6 1.6 1.6 4.0 2.7 0.4 TiO.sub.2 1 0 1 1 0 0 0 SnO 0.04 0.04 0.04 0.04 0.10 0.05 0.10 R′O = MgO + 20.16 19.16 18.16 15.16 15.7 16.6 15.3 CaO + SrO + BaO + ZnO (MgO + BaO)/R′O 0.51 0.54 0.27 0.54 0.38 036 0.63 Al.sub.2O.sub.3/R′O 0.54 0.67 0.70 1.04 0.80 0.85 0.97 I value 15.29 −14.71 −13.71 5.79 −14.4 −31.4 −11.15 density (g/cm.sup.3) 2.69 2.68 2.59 2.61 2.61 2.59 2.63 expansion coefficient 42 39.9 37.1 36.4 34.3 35.6 37.0 (×10.sup.−7/° C.) Young's 79.5 79.7 81.0 79.4 79.2 81.7 81.5 modulus (GPa) specific modulus 29.5 29.7 31.3 30.4 30.3 31.5 31.0 (GPa/(g/cm.sup.3)) 1200° C. surface 338.9 357.4 336.5 413.1 359.7 364.5 360.3 tension (mN/m) Vickers hardness 6.28 6.54 6.61 6.85 6.49 6.30 6.15 (GPa) number of bubbles 0 0 0 5 1 4 2 having bubble diameter >0.1 mm per Kg glass T.sub.m (° C.) 1595.5 1603.8 1623.4 1613.7 1613 1618 1638 T.sub.w (° C.) 1221.4 1233.4 1236.0 1277.6 1295.4 1271.4 1321.2 T.sub.l (° C.) 1150 1230 1260 1290 1110 1120 1110 annealing point 778.3 794.2 800.4 835.6 812 819 821 T.sub.a (° C.) strain point T.sub.st 727.3 741.1 752.6 784.7 752 746 757 (° C.) glass stability 0.83 1.17 1.26 1.40 0.59 0.60 0.55 factor D refractivity n.sub.D 1.538 1.513 1.533 1.532 1.525 1.521 1.519

(75) TABLE-US-00004 TABLE 4 Comparative Comparative Comparative Comparative Comparative Comparative Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 SiO.sub.2 68.83 72.5 70.1 70.8 70.8 69.1 Al.sub.2O.sub.3 15.6 13.3 13.5 12.55 12.55 11.6 SiO.sub.2 + Al.sub.2O.sub.3 84.43 85.8 83.6 83.35 83.35 80.7 MgO 6.2 3.6 2.1 2.35 2.35 2.8 CaO 3.6 5.0 3.5 3.4 3.4 4.3 SrO 2.0 2.6 3.3 1.3 1.3 2.4 BaO 1.3 2.1 3.7 5.7 5.7 6.7 ZnO 2.4 0.8 3.7 3.6 3.6 2.5 TiO.sub.2 0 0 0 0 0 0 ZrO.sub.2 0 0 0 0.2 0 0 PbO 0 0 0 0 0.2 0 SnO 0.07 0.10 0.10 0.1 0.1 0.1 La.sub.2O.sub.3 0 0 0 0 0 0.5 R′O = MgO + 15.5 14.1 16.3 16.35 16.35 18.7 CaO + SrO + BaO + ZnO (MgO + BaO)/R′O 0.48 0.40 0.36 0.49 0.49 0.51 Al.sub.2O.sub.3/R′O 1.01 0.94 0.83 0.77 0.77 0.62 I value −37.87 −14.7 −17.2 2.075 2.075 −2.55 density(g/cm.sup.3) 2.55 2.55 2.63 2.65 2.68 2.70 expansion coefficient 32.0 33.4 37.2 37.7 39.2 40.1 (×10.sup.−7/° C.) Young's 83.3 81.1 79.0 78.9 77.5 79.5 modulus(GPa) specific modulus 32.6 31.8 30.0 29.8 28.9 29.4 (GPa/(g/cm.sup.3)) 1200° C. surface 364.2 358.7 363.6 360.7 333.8 346.7 tension (mN/m) Vickers hardness 6.44 6.37 6.17 6.89 6.49 6.26 (GPa) number of bubbles 3 1 1 2 0 0 having bubble diameter >0.1 mm per Kg glass T.sub.m (° C.) 1640 1635 1633 1657.5 1607.3 1618.7 T.sub.w (° C.) 1283.8 1329.6 1290.4 1316.5 1265.3 1271.1 T.sub.l (° C.) 1140 1120 1130 1290 1240 1240 annealing point 833 816 826 816.3 787.8 823.3 T.sub.a (° C.) strain point 758 747 753 768.6 731.6 775.1 T.sub.st(° C.) glass stability 0.61 0.59 0.60 1.29 1.23 1.10 factor D refractivity n.sub.D 1.527 1.519 1.528 1.540 1.547 1.544

(76) It is seen from the results in Tables 1-4: when the composition for glass that contains SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, SrO, BaO, ZnO and TiO.sub.2 in specific contents in the present invention is used to prepare glass, especially in the case that the content of SiO.sub.2+Al.sub.2O.sub.3 is >80 mol %, the I value is >0, 0.8≥(MgO+BaO)/R′O≥0.34, and 0.6≤Al.sub.2O.sub.3/R′O≤1 (in mole percent) in the composition for glass, the prepared glass has excellent properties, such as higher strain point, higher Young's modulus, higher specific modulus, higher Vickers hardness, higher chemical stability, higher stability of glass formation, lower forming temperature, lower melting temperature, and lower liquidus temperature, etc. Specifically, the density of the obtained alkaline-earth aluminosilicate glass is smaller than 2.67 g/cm.sup.3, the Young's modulus is greater than 75 GPa, the specific modulus is greater than 29 GPa/(g/cm.sup.3), the thermal expansion coefficient at 50-350° C. is smaller than 39×10.sup.−7/° C., the refractivity n.sub.D is greater than 1.53, the forming temperature T.sub.w corresponding to 35,000 P viscosity is lower than 1,320° C., the melting temperature T.sub.m corresponding to 200 P viscosity is lower than 1,650° C., the liquidus temperature T.sub.l is lower than 1,220° C., the strain point T.sub.st is 750° C. or above, the annealing point T.sub.a is 790° C. or above, the glass formation stability factor D is smaller than 1.0, the surface tension at 1,200° C. is smaller than 350 mN/m, the Vickers hardness is greater than 6.4 GPa, and the number of bubbles having bubble diameter>0.1 mm per Kg glass substrate is so low that the bubbles are invisible.

(77) While the present invention is described above in detail in some preferred embodiments, the present invention is not limited to those embodiments. Various simple variations, including combinations of the technical features in any other appropriate way, can be made to the technical scheme of the present invention within the scope of the technical concept of the present invention, but such variations and combinations shall be deemed as disclosed content in the present invention and falling in the protection scope of the present invention.