Lithium-silicon glass, tempered glass, and preparation method and application thereof

Abstract

The present invention relates to lithium silicate glass, tempered glass and preparation method and application thereof. The lithium silicate glass comprises, by mass percentage: SiO 2 69%~76%,Al 2 O 3 0~9%、K 2 O 0~4.5%, MgO 0~2%, Na 2 O 0~5%、Li 2 O 9%~16%, ZrO 2 0~5.2%、B 2 O 3 0~1%、P 2 O 5 2% to 4.5%, CaO 0 to 4% and ZnO 0 to 3%; the lithium silicate glass contains nanocrystalline cores, and the crystal phase of the nanocrystalline cores includes lithium disilicate. Through the reasonable proportion of the components, the lithium silicate glass has a higher visible light transmittance, a higher softening temperature, a higher elastic modulus and a higher strengthening stress after chemical strengthening, and has better fire resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of glass products, and in particular to lithium silicate glass, tempered glass, and a preparation method and application thereof. Background Art

[0002] Fireproof glass, in fire prevention, mainly controls the spread of fire or isolates smoke. It is a measure-type fireproof material, and its fireproof effect is evaluated by fire resistance. It is a special glass that has been processed and treated with special technology and can maintain its integrity and heat insulation in the prescribed fire resistance test. The mainstream single-piece fireproof glass on the market includes cesium potassium fireproof glass, borosilicate fireproof glass and microcrystalline fireproof glass. Cesium potassium fireproof glass has high strength, but it is easy to burst when subjected to thermal shock; borosilicate fireproof glass has a low thermal expansion coefficient and good thermal shock resistance; but the strength of the glass is low; microcrystalline fireproof glass has high strength and fire resistance, but the visible light transmittance is low, which limits the application of microcrystalline fireproof glass. Summary of the invention

[0003] Based on this, it is necessary to provide a lithium silicate glass, tempered glass with high transmittance and good fire resistance, and a preparation method and application thereof.

[0004] In one aspect of the present invention, there is provided a lithium silicate glass, which comprises, by weight percentage:

[0005]

[0006]

[0007] The lithium silicate glass contains nanocrystalline cores, and the crystal phase of the nanocrystalline cores includes lithium disilicate.

[0008] In some embodiments, the crystalline phase of the nanocrystalline core further includes at least one of cristobalite, petalite, β-spodumene and wollastonite.

[0009] In some embodiments, the volume proportion a of the nanocrystal core satisfies: 0<a<1%.

[0010] In some embodiments, the lithium silicate glass satisfies at least one of the conditions (1) to (8):

[0011] (1) SiO in the lithium silicate glass 2 The mass percentage is 70% to 73%;

[0012] (2) Al in the lithium silicate glass 2 O 3 The mass percentage is 2.5% to 8%;

[0013] (3) K in the lithium silicate glass 2 The mass percentage of O is 0-1%;

[0014] (4) Na in the lithium silicate glass 2 The mass percentage of O is 0-4%;

[0015] (5) Li in the lithium silicate glass 2 The mass percentage of O is 9.8% to 13.4%;

[0016] (6) ZrO in the lithium silicate glass 2 The mass percentage is 1.5% to 4.8%;

[0017] (7) The mass percentage of CaO in the lithium silicate glass is 0 to 1.5%;

[0018] (8) The mass percentage of ZnO in the lithium silicate glass is 0 to 1.5%.

[0019] In some embodiments, the lithium silicate glass satisfies at least one of the conditions (1) to (4):

[0020] (1) The thermal expansion coefficient of the lithium silicate glass is 89×10 -7 / ℃~107×10 -7 / ℃;

[0021] (2) The softening temperature of the lithium silicate glass is 575°C to 645°C;

[0022] (3) The elastic modulus of the lithium silicate glass is 78 GPa to 85 GPa;

[0023] (4) The visible light transmittance of the lithium silicate glass is ≥90%.

[0024] In a second aspect, the present invention further provides a method for preparing lithium silicate glass, comprising the following steps:

[0025] Weigh the raw materials according to the components of the lithium silicate glass of the first aspect above;

[0026] Mixing and melting the raw materials to prepare molten glass;

[0027] forming and annealing the glass liquid to prepare precursor glass; and

[0028] The precursor glass is heat treated to prepare the lithium silicate glass.

[0029] In a third aspect, the present invention further provides a tempered glass obtained by subjecting the lithium-silicon glass of the first aspect to chemical strengthening treatment.

[0030] In some embodiments, the tempered glass satisfies at least one of the following conditions:

[0031] (1) The surface stress value CS of the tempered glass is 684 MPa to 1058 MPa;

[0032] (2) The stress depth Dol-Na of the tempered glass is 136 μm to 182 μm;

[0033] (3) The softening temperature of the tempered glass after burning with an open flame is 865°C to 940°C;

[0034] (4) The elastic modulus of the tempered glass after burning with an open flame is 92 GPa to 102 GPa;

[0035] (5) The fire resistance time of the tempered glass is ≥ 4h.

[0036] In a fourth aspect, the present invention further provides a method for preparing a tempered glass, comprising the following steps to prepare the tempered glass of the third aspect:

[0037] The lithium silicate glass is strengthened in a molten salt; the molten salt comprises 0-15% sodium nitrate and 85%-100% potassium nitrate in terms of mass percentage.

[0038] In a fifth aspect, the present invention further provides the use of the tempered glass according to the third aspect in the preparation of fire-resistant glass.

[0039] The lithium silicate glass component includes silicon oxide, lithium oxide and phosphorus pentoxide in a specific content ratio, and the lithium silicate glass contains nanocrystalline cores, and the crystal phase of the nanocrystalline cores includes lithium disilicate. Through the reasonable ratio of the components, the lithium silicate glass has a high transmittance, and after chemical strengthening, it has a high visible light transmittance, a high softening temperature, a high elastic modulus and a high strengthening stress, and has good fire resistance. DETAILED DESCRIPTION

[0040] For ease of understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0042] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features. Unless otherwise specified, the "include" and "comprise" mentioned in the present invention represent open or closed. For example, the "include" and "comprises" may mean that other components not listed may also be included or comprised, or may only include or comprise the listed components.

[0043] In the present invention, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0044] The percentage content involved in the present invention, unless otherwise specified, refers to mass percentage for solid-liquid mixing and solid-solid mixing, and refers to volume percentage for liquid-liquid mixing.

[0045] The percentage concentrations involved in the present invention, unless otherwise specified, refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of the component.

[0046] The temperature parameters in the present invention, if not specifically limited, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the precision range controlled by the instrument.

[0047] In one aspect of the present invention, there is provided a lithium silicate glass, which comprises, by weight percentage:

[0048]

[0049] The lithium silicate glass contains nanocrystalline cores, and the crystal phase of the nanocrystalline cores includes lithium disilicate.

[0050] The above-mentioned lithium silicate glass components include silicon oxide, lithium oxide and phosphorus pentoxide in a specific content ratio, and the lithium silicate glass contains nanocrystalline cores, and the crystalline phase of the nanocrystalline cores includes lithium disilicate. Nanocrystalline cores refer to crystal cores with a particle size of ≤1nm. The nanocrystalline cores have a smaller particle size, and the lithium silicate glass still exhibits the properties of the glass phase, so it has a higher transmittance. The nanocrystalline cores can quickly crystallize after being heated by fire, thereby improving the softening temperature and mechanical strength of the glass, and are particularly suitable for the preparation of fireproof glass. Through the reasonable ratio of components, the above-mentioned lithium silicate glass has a higher visible light transmittance, a higher softening temperature, a higher elastic modulus and a higher strengthening stress after chemical strengthening, and has better fire resistance.

[0051] In some embodiments, the crystalline phase of the nanocrystalline core further includes at least one of cristobalite, petalite, petalite, β-spodumene and wollastonite.

[0052] In some embodiments, the volume proportion a of the nanocrystalline core satisfies: 0<a<1%. The volume proportion of the nanocrystalline core is within the above range, the volume proportion is small, and the lithium silicate glass mainly exhibits the properties of the glass phase and has a high visible light transmittance.

[0053] SiO 2 It is a network-forming oxide and a necessary component for forming the glass skeleton. It can improve the strength and chemical stability of the glass, and can make the glass have a higher strain point and a lower thermal expansion coefficient. 2 If the content of SiO is too low, the thermal expansion coefficient will increase too much, the forming and chemical resistance will be reduced, and there is a tendency to crystallize; 2 If the content of SiO is too high, the melting and clarification temperature of the glass will be higher, and the viscosity will increase, making it difficult to homogenize the glass, which is not conducive to the glass molding process. 2 The mass percentage of SiO in lithium silicate glass is 69% to 76%. 2 The mass percentage of SiO in lithium silicate glass is within the range of any of the following values: 69%, 70%, 71%, 72%, 73%, 74%, 75% or 76%. 2 The mass percentage is 70% to 73%.

[0054] Al 2 O 3 It can also stabilize the network and also provide improved mechanical properties and chemical durability. In an embodiment of the present invention, Al in lithium silicate glass 2 O 3 The mass percentage of Al in lithium silicate glass is 0-9%. 2 O 3The mass percentage of Al in lithium silicate glass is within the range of any of the following numerical values: 0, 1%, 2%, 2.5%, 3%, 4%, 5%, 6%, 7%, 8% or 9%. 2 O 3 The mass percentage is 2.5% to 8%.

[0055] Li 2 O is one of the components that form the nanocrystalline core phase, and also serves as a cosolvent and a component that enhances ion exchange capacity. 2 The mass percentage of O is 9% to 16%. 2 The mass percentage of O is within the range of any of the following values: 9%, 9.8%, 10%, 11%, 12%, 13%, 13.4%, 14%, 15% or 16%. 2 The mass percentage of O is 9.8% to 13.4%.

[0056] Na 2 The role of O and Li 2 O is similar to lithium silicate glass and is used as a co-solvent and a component that enhances ion exchange capacity. In the embodiment of the present invention, Na 2 The mass percentage of O is 0-5%. 2 The mass percentage of O is within the range of any of the following values: 0, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%. 2 The mass percentage of O is 0 to 4%.

[0057] K 2 The role of ONa 2 O is close to Mg and can be used as a solvent in glass, but K 2 Too much O will reduce the power of Na-K ion exchange. In the embodiment of the present invention, K in lithium silicate glass 2 The mass percentage of O is 0 to 4.5%. 2 The mass percentage of O is in the range of any of the following values: 0 to 4.5%. 2 The mass percentage of O is 0 to 1%.

[0058] MgO is a network exo-oxide. MgO helps to lower the melting point of glass, reduce the viscosity of glass at high temperatures, promote the melting and clarification of glass, enhance the stability of the glass network space at low temperatures, and reduce the thermal expansion coefficient of glass to a certain extent. In an embodiment of the present invention, the mass percentage of MgO in lithium silicate glass is 0 to 2%. Optionally, the mass percentage of MgO in lithium silicate glass is within the range of any of the following numerical values: 0, 0.1%, 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.5%, 1.6%, 1.8% or 2%.

[0059] The role of ZnO is similar to that of MgO, which is beneficial to reduce the high temperature viscosity of glass, modify the glass structure, and improve the strength and chemical stability of glass. In an embodiment of the present invention, the mass percentage of ZnO in the lithium silicate glass is 0 to 3%. Optionally, the mass percentage of ZnO in the lithium silicate glass is within the range of any of the following numerical values: 0, 0.5%, 1%, 1.5%, 2%, 2.5% or 3%. Furthermore, the mass percentage of ZnO in the lithium silicate glass is 0 to 1.5%.

[0060] The role of CaO is similar to that of MgO. In an embodiment of the present invention, the mass percentage of CaO in the lithium silicate glass is 0 to 4%. Optionally, the mass percentage of CaO in the lithium silicate glass is within the range of any of the following numerical values: 0, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 4%. Furthermore, the mass percentage of CaO in the lithium silicate glass is 0 to 1.5%.

[0061] ZrO 2 Added as a common nucleating agent. ZrO 2 The stability of the lithium silicate glass system can be improved by significantly reducing the glass devitrification and lowering the liquidus temperature during the formation process. 2 The mass percentage of ZrO in lithium silicate glass is 0 to 5.2%. 2 The mass percentage of ZrO in lithium silicate glass is within the range of any of the following values: 0, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 4.8%, 5% or 5.2%. 2 The mass percentage is 1.5% to 4.8%.

[0062] P 2 O 5 It can be used as a nucleating agent to promote glass nucleation. In the embodiment of the present invention, P in lithium silicate glass 2 O 5 The mass percentage of P in lithium silicate glass is 2% to 4.5%.2 O 5 The mass percentage is within the range consisting of any of the following numerical values: 2%, 2.5%, 3%, 3.5%, 4% or 4.5%.

[0063] B 2 O 3 It helps to provide lithium silicate glass with a low melting temperature and can promote the formation of nanocrystalline nuclei. In an embodiment of the present invention, B in lithium silicate glass 2 O 3 The mass percentage of B in lithium silicate glass is 0-1%. 2 O 3 The mass percentage is within the range consisting of any of the following numerical values: 0, 0.2%, 0.4%, 0.5%, 0.6%, 0.8% or 1%.

[0064] In some embodiments, the thermal expansion coefficient of lithium silicate glass at 50°C to 500°C is 89×10 -7 / ℃~107×10 -7 / ℃.

[0065] In some of the embodiments, the softening temperature of the lithium silicate glass is 575°C to 645°C.

[0066] In some embodiments, the elastic modulus of the lithium silicate glass is 78 GPa to 85 GPa. When the elastic modulus of the lithium silicate glass is within the above range, the mechanical strength of the lithium silicate glass is better.

[0067] In some embodiments, the visible light (400nm-800nm) transmittance of the lithium silicate glass is ≥90%. When the visible light transmittance of the lithium silicate glass is within the above range, the lithium silicate glass presents a transparent appearance.

[0068] Another embodiment of the present invention further provides a method for preparing lithium silicate glass, comprising the following steps S110 to S140.

[0069] S110: Weigh raw materials according to the composition of lithium silicate glass.

[0070] S120: Mixing and melting raw materials to prepare glass liquid.

[0071] In some of the embodiments, the melting temperature is 1500° C. to 1600° C.; and the melting time is 4 h to 10 h.

[0072] S130: shaping and annealing the glass liquid to prepare precursor glass.

[0073] In some of the embodiments, the forming process includes one of float forming, slot down-draw forming, overflow forming, down-draw forming, flat-draw forming, draw-up forming and calendering forming.

[0074] S140: heat-treating the precursor glass to prepare lithium silicate glass.

[0075] In some embodiments, the heat treatment temperature is 560°C to 680°C, and the heat treatment time is 4h to 8h. Further, the heat treatment temperature is 570°C to 650°C, and the heat treatment time is 4h to 8h.

[0076] Another embodiment of the present invention further provides a tempered glass obtained by subjecting the above-mentioned lithium silicate glass to chemical strengthening treatment.

[0077] The tempered glass has a good surface stress value and a large stress depth, and the tempered glass has good thermal shock resistance.

[0078] In some embodiments, the surface stress value CS of the tempered glass is 684 MPa to 1058 MPa. Further, the surface stress value CS of the tempered glass is 785 MPa to 994 MPa. When the surface stress value CS of the tempered glass is within the above range, the tempered glass has good thermal shock resistance, and the tempered glass is prevented from cracking due to heat.

[0079] In some embodiments, the stress depth Dol-Na of the tempered glass is 136 μm to 182 μm. Further, the stress depth Dol-Na of the tempered glass is 153 μm to 178 μm. When the stress depth Dol-Na of the tempered glass is within the above range, the tempered glass surface has a stress layer of appropriate thickness, and the tempered glass has good thermal shock resistance.

[0080] The above-mentioned strengthened glass is prepared by chemically strengthening the above-mentioned lithium silicate glass. The glass contains nanocrystalline nuclei. After being burned by an open flame, the strengthened glass will quickly precipitate a crystalline phase when heated, thereby further improving the softening temperature and elastic modulus of the strengthened glass, and having better fire resistance.

[0081] In some embodiments, the softening temperature of the tempered glass after burning with an open flame is 865° C. to 940° C. Further, the softening temperature of the tempered glass after burning with an open flame is 872° C. to 934° C. The softening temperature of the tempered glass after burning with an open flame is within the above range, the softening temperature is relatively high, the tempered glass is not easy to soften and collapse under long-term burning, and the fire resistance is good.

[0082] In some embodiments, the elastic modulus of the strengthened glass after burning with an open flame is 92 GPa to 102 GPa. Further, the elastic modulus of the strengthened glass after burning with an open flame is 97 GPa to 102 GPa. After burning with an open flame, the strengthened glass precipitates a crystalline phase, and the elastic modulus of the strengthened glass is also improved, which has better mechanical strength.

[0083] In some embodiments, the fire resistance time of the tempered glass is ≥4 hours. Further, the fire resistance time of the tempered glass is ≥5 hours.

[0084] Another embodiment of the present invention further provides a method for preparing the above-mentioned tempered glass, comprising the following step S210.

[0085] S210: Strengthening the lithium silicate glass in a molten salt, wherein the molten salt comprises 0-15% sodium nitrate and 85%-100% potassium nitrate in terms of mass percentage.

[0086] In some embodiments, the temperature of the strengthening treatment is 380° C. to 420° C.; and the time of the strengthening treatment is 2 h to 6 h.

[0087] Another embodiment of the present invention further provides use of the tempered glass according to the third aspect in preparing fire-resistant glass.

[0088] The following are specific embodiments.

[0089] Embodiments 1 to 12 and comparative examples 1 to 6 were prepared according to the design components in Tables 1 to 3. After being fully mixed, they were melted in a platinum crucible at 1500°C to 1600°C for 8 hours, and stirred with a platinum stirring paddle. After the stirring paddle was withdrawn, the temperature was reduced to 1300°C to 1400°C, and the temperature was kept for 2 hours for homogenization. The glass blocks were cast into an iron mold to form glass blocks of about 80*160 mm in size. The mold was preheated to 450°C before casting. After the glass blocks were hardened, they were immediately transferred to an annealing furnace for annealing, kept for 2 hours, and then reduced to 140°C after 6 hours, cooled naturally, and taken out for use.

[0090] The above glass samples were pre-cored at 560℃~680℃, kept warm for 4h~8h, cut into 140*140*6mm glass sheets by Shenyang Kejing's STX-1203 wire cutting machine, thinned and polished by Shenzhen Haide's HD-640-5L double-sided grinding and polishing machine, and tested for thermal expansion coefficient of 50℃~500℃ by NETZSCH Classic 402PC thermal expansion instrument, and the glass softening temperature was determined according to the national standard GB / T-28195-2011. The transmittance in the wavelength range of 400nm~800nm ​​was tested by Lambda950 UV-visible spectrophotometer of PerkinElmer, USA. The elastic modulus of glass was tested by JC / T 687-1997(2007) "Test Method for Elastic Modulus, Shear Modulus and Poisson's Ratio of Glass Materials". The test results are recorded in Tables 1 to 3.

[0091] The glass samples that have undergone the pre-nuclear treatment are immersed in a mixed solution of 0-15wt% sodium nitrate and 85wt%-100wt% potassium nitrate at 380℃-420℃ for 2h-6h for chemical strengthening treatment. The surface compressive stress CS (Mpa) and stress depth Dol-Na (μm) are tested by SLP2000 and FSM-6000LE surface stress gauges of Orihara Industries Co., Ltd., Japan. The test results are recorded in Tables 1 to 3.

[0092] The central area of ​​the above-mentioned tempered glass was burned with a natural gas gun, and the temperature of the flame and the contact surface of the glass was measured to be 900℃~950℃. After burning for different time periods, the degree of glass cracking or severe deformation was observed, and the fire failure time was recorded; the central area of ​​the sample burned for ≥3 hours was cut into φ5*30mm samples, and the crystallized sample after the above-mentioned burning fire resistance test was cut into 20*20mm. The crystal phase type was tested by Bruker's X-ray diffractometer Bruker D8 advance, and the thermal expansion coefficient, softening temperature, transmittance and elastic modulus at 50℃~500℃ were tested according to the above-mentioned test method. Recorded in Tables 4 to 6.

[0093] Table 1

[0094]

[0095] Table 2

[0096]

[0097]

[0098] Table 3

[0099]

[0100]

[0101] Table 4

[0102]

[0103] Table 5

[0104]

[0105]

[0106] Table 6

[0107]

[0108] It can be seen from the relevant data in Tables 1 to 6 that the lithium silicate glasses of Examples 1 to 6, in terms of mass percentage, include: SiO2 69%~75.44%,Al 2 O 3 0~8.97%、K 2 O 0~4.39%, MgO 0~0.5%, Na 2 O 0~5%、Li 2 O 9%~15.4%, ZrO 2 0~5.2%、B 2 O 3 0~0.5%、P 2 O 5 2% to 4.37%, CaO 0 to 3.75% and ZnO 0 to 2.92%; the lithium silicate glass contains nanocrystalline nuclei, the crystalline phase of which includes lithium disilicate, and optionally includes at least one of cristobalite, petalite, petalite, wollastonite and β-spodumene. The thermal expansion coefficient of the lithium silicate glass of Examples 1 to 6 at 50 to 500°C is 89.4×10 -7 ℃~107×10 -7 ℃, softening temperature is 575℃~642℃, elastic modulus is 79GPa~84GPa, visible light transmittance is 90.8%~91%. The surface stress value CS of the strengthened glass prepared by chemical strengthening treatment of Examples 1~6 is 684MPa~1058MPa, and the stress depth Dol-Na is 136μm~182μm. After calcination, the thermal expansion coefficient of the strengthened glass of Examples 1~6 at 50~500℃ is 80.4×10 -7 ℃~98.4×10 -7 ℃, softening temperature is 865℃~962℃, elastic modulus is 92GPa~102GPa, visible light transmittance is 78.6%~90.2%. The fire resistant failure time of tempered glass is ≥4 hours.

[0109] The lithium silicate glass of Examples 7 to 12 comprises, by weight percentage, the following components: SiO 2 70%~73%,Al 2 O 3 2.6%~8.4%, K 2 O 0~1.5%, MgO 0~2%, Na 2 O 0~4%、Li 2 O 9.8%~13.4%, ZrO 2 1.5%~4.8%, B 2 O 3 0~1%、P 2 O 52% to 4.4%, CaO 0 to 1.5% and ZnO 0 to 1.5%; the lithium silicate glass contains nanocrystalline cores, the crystal phase of the nanocrystalline cores includes lithium disilicate, and optionally includes at least one of cristobalite, petalite and β-spodumene. The thermal expansion coefficient of the lithium silicate glass of Examples 7 to 12 at 50 to 500°C is 89.5×10 -7 ℃~98.2×10 -7 ℃, softening temperature is 583℃~635℃, elastic modulus is 78GPa~83GPa, visible light transmittance is 90.9%~91%. The surface stress value CS of the strengthened glass prepared by chemical strengthening treatment in Examples 7~12 is 785MPa~994MPa, and the stress depth Dol-Na is 153μm~178μm. After calcination, the thermal expansion coefficient of the strengthened glass in Examples 7~12 at 50~500℃ is 78.5×10 -7 ℃~88.1×10 -7 ℃, softening temperature is 872℃~934℃, elastic modulus is 97GPa~102GPa, visible light transmittance is 62.7%~90.6%. The fire resistant failure time of tempered glass is more than 5 hours.

[0110] The lithium silicate glass of Comparative Example 1 is different from that of Example 11 in that it has not been pre-nuclearized and does not contain nanocrystalline nuclei; its thermal expansion coefficient at 50-500°C is 90.8×10 -7 ℃, softening temperature is 618℃, elastic modulus is 82GPa, visible light transmittance is 91%, and the performance is basically the same as that of the lithium silicate glass in Example 11. The surface stress value CS of the strengthened glass prepared by chemical strengthening treatment in Comparative Example 1 is 785MPa, and the stress depth Dol-Na is 153μm, and the performance is basically the same as that of the strengthened glass in Example 11. After calcination, the thermal expansion coefficient of the strengthened glass in Comparative Example 1 at 50-500℃ is 91.2×10 -7 ℃, softening temperature is 615℃, elastic modulus is 82GPa, visible light transmittance is 90.4%. The fire failure time of the tempered glass is greater than 5 hours, and it softens and collapses when heated; this may be because the tempered glass of Comparative Example 1 does not contain nanocrystalline nuclei, and the crystallization cannot be quickly precipitated when heated, which increases the softening temperature of the tempered glass, so the fire resistance is poor.

[0111] The difference between Comparative Example 2 and Example 11 is that the lithium silicate glass has not been strengthened. After burning, the lithium silicate glass of Comparative Example 2 has a fire failure time of less than 1 hour and explodes after burning. It can be seen that the lithium silicate glass of Comparative Example 2 has not been chemically strengthened and has poor thermal shock resistance. The thermal expansion coefficient of the lithium silicate glass of Comparative Example 2 at 50-500°C after burning is 87.9×10 -7℃, the softening temperature is 648℃, the elastic modulus is 86GPa, the visible light transmittance is 90.1%, and the softening temperature has not increased significantly. This may be because the glass explodes quickly when heated and is not enough to form a large number of crystal phases to increase the softening temperature.

[0112] The lithium silicate glass component of Comparative Example 3 does not contain P 2 O 5 , it is difficult to form nanocrystalline nuclei. After burning, the chemically strengthened glass is difficult to precipitate the crystal phase, softens and collapses when heated, and the fire-resistant failure time is less than 0.1 hours.

[0113] The components of the lithium silicate glass of Comparative Examples 4 to 6 are not within the scope of the present invention. The tempered glasses obtained by chemical tempering treatment in Comparative Examples 4 to 6 have a fire resistance time of ≤3 hours after burning, and their fire resistance is inferior to that of the tempered glasses of Examples 1 to 12.

[0114] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The above-described embodiments only express several implementation methods of the present invention, which are convenient for understanding the technical solutions of the present invention in detail, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present invention are all within the protection scope of the attached claims described in the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the contents of the attached claims, and the description can be used to interpret the contents of the claims.

Claims

1. A lithium silicate glass, It is characterized in that In terms of mass percentage, its components include: Not. 2 69%~73%, <h2 style=";text-align:left;direction:ltr">Al<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> O<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> 3.4%~8.5% K 2 O 0~1.5%, MgO 0.5%~1%, So 2 2.2%~5%、 Li 2 9%~13.4%, ZrO 2 1.5%~4%、 B 2 O 3 0~1%、 P 2 O 5 2%~4.4%, CaO 0~1%, and ZnO 0.1%~1.5%; The lithium silicate glass contains nanocrystalline cores, the particle size of the nanocrystalline cores is ≤1 nm, the volume proportion a of the nanocrystalline cores satisfies: 0<a<1%; and the crystal phase of the nanocrystalline cores includes lithium disilicate.

2. The lithium silicate glass according to claim 1, It is characterized in that The crystalline phase of the nanocrystalline core also includes at least one of cristobalite, petalite, petalite, β-spodumene and wollastonite.

3. The lithium silicate glass according to claim 1, It is characterized in that The SiO in the lithium silicate glass 2 The mass percentage is 70%~73%.

4. The lithium silicate glass according to claim 1, It is characterized in that The lithium silicate glass has K 2 The mass percentage of O is 0~1%.

5. The lithium silicate glass according to claim 1, It is characterized in that The lithium silicate glass 2 The mass percentage of O is 9.8%~13.4%.

6. The lithium silicate glass according to any one of claims 1 to 5, It is characterized in that The thermal expansion coefficient of the lithium silicate glass is 90.7×10 -7 / ℃~98.2×10 -7 / ℃.

7. The lithium silicate glass according to any one of claims 1 to 5, It is characterized in that The softening temperature of the lithium silicate glass is 594°C to 642°C.

8. The lithium silicate glass according to any one of claims 1 to 5, It is characterized in that The elastic modulus of the lithium silicate glass is 79 GPa~83 GPa.

9. The lithium silicate glass according to any one of claims 1 to 5, It is characterized in that The visible light transmittance of the lithium silicate glass is ≥90.9%.

10. A method for preparing lithium silicate glass, It is characterized in that The following steps are involved: Weigh the raw materials according to the components of the lithium silicate glass according to any one of claims 1 to 9; Mixing and melting the raw materials to prepare molten glass; forming and annealing the glass liquid to prepare precursor glass; and The precursor glass is heat treated to prepare the lithium silicate glass.

11. A tempered glass, It is characterized in that The lithium silicate glass is obtained by chemically strengthening the lithium silicate glass as described in any one of claims 1 to 9.

12. The tempered glass according to claim 11, It is characterized in that The surface stress value CS of the tempered glass is 897 MPa~994 MPa.

13. The tempered glass according to claim 11, It is characterized in that The stress depth Dol-Na of the tempered glass is 162 μm to 178 μm.

14. The tempered glass according to claim 11, It is characterized in that The softening temperature of the tempered glass after burning with an open flame is 872°C to 940°C.

15. The tempered glass according to claim 11, It is characterized in that The elastic modulus of the tempered glass after burning with an open flame is 98 GPa to 100 GPa.

16. The tempered glass according to claim 11, It is characterized in that The fire resistance time of the tempered glass is ≥5h.

17. A method for preparing tempered glass, It is characterized in that The method comprises the following steps of preparing the tempered glass according to any one of claims 11 to 16: The lithium silicate glass is strengthened in a molten salt; the molten salt comprises 0-15% sodium nitrate and 85%-100% potassium nitrate in terms of mass percentage.

18. Use of the tempered glass according to any one of claims 11 to 16 in the preparation of fireproof glass.

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