WO2019233291A1

WO2019233291A1 - Phosphorus-free alkali-free glass batch suitable for float shaping and phosphorus-free alkali-free glass prepared therefrom

Info

Publication number: WO2019233291A1
Application number: PCT/CN2019/088252
Authority: WO
Inventors: 彭寿; 马立云; 王萍萍; 曹欣; 石丽芬; 倪嘉; 韩娜; 赵凤阳; 仲召进; 单传丽; 王巍巍; 崔介东; 操芳芳; 高强
Original assignee: 中建材蚌埠玻璃工业设计研究院有限公司
Priority date: 2018-06-05
Filing date: 2019-05-24
Publication date: 2019-12-12
Also published as: CN108558200A

Abstract

A phosphorous-free alkali-free glass batch suitable for float shaping and a phosphorous-free alkali-free glass prepared therefrom, wherein the phosphorous-free alkali-free glass batch comprises the following components in mass percentages: 49.5%-59.5% of SiO₂, 2%-8% of GeO₂, 15%-19.1% of Al₂O₃, 0.1%-0.3% of ZrO₂, 3.7%-6% of CaO, 6%-8.3% of B₂O₃, 2%-3.8% of MgO, 6%-7% of SrO, 0.1%-0.2% of SnO, 0.1%-0.25% of MoO₃, and 0.1%-0.25% of WO₃, wherein the value of SiO₂ + GeO₂ is 57.5%-61.8%, and the value of SiO₂ + Al₂O₃ + ZrO₂ is 68.9%-78.8%, and preferably 75%-77%. The phosphorous-free alkali-free glass batch and the alkali-free glass prepared therefrom effectively reduce the viscosity of alkali-free aluminosilicate glass after being melted, and reduce the surface tension of glass after being melted.

Description

Phosphorus-free and alkali-free glass batch suitable for float molding and phosphorus-free and alkali-free glass prepared therefrom

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on June 05, 2018, with application number 201810570809.6, and the invention name is "a phosphorus-free and alkali-free glass batch suitable for float molding", and its entire contents Incorporated by reference in this application.

Technical field

The present application relates to the field of flexible glass production, and in particular to an alkali-free glass batch suitable for float molding and an alkali-free glass prepared by the same.

Background technique

Flexible glass is a new type of special glass. Compared with ordinary glass, it not only has the hardness, light transmission, heat resistance, and chemical stability of ordinary glass, but also has the characteristics of flexible, lightweight, and processable plastics. Flexible glass can be used to make touch panels such as mobile phones and tablet computers, substrates for flexible displays, and substrates for organic thin-film solar cells. The preparation methods of flexible glass mainly include primary forming method and secondary forming method. The primary forming method mainly includes overflow down-draw method and float method; the secondary forming method mainly includes chemical thinning method and re-drawing method.

At present, flexible glass mainly includes alkali-free aluminosilicate glass, soda lime glass and high aluminosilicate glass; among them, alkali-free aluminosilicate glass is mainly used as electronic information display such as TFT-LCD (thin film transistor liquid crystal display) Screen substrate glass. The alkali-free aluminosilicate glass has more alumina in the formula, which makes the molten glass viscosity higher at high temperature. When the alkali-free aluminosilicate glass is prepared by the float method, it is necessary to increase the temperature to reduce the viscosity of the glass liquid. To facilitate the formation of glass. However, higher temperatures have higher requirements for glass production equipment, which increases the production cost of glass.

In view of this, on the basis of the existing alkali-free aluminosilicate glass, how to further reduce the viscosity of the glass after melting is a technical problem to be urgently solved by those skilled in the art.

Summary of the Invention

The application provides a phosphorus-free alkali-free glass batch suitable for float molding and a phosphorus-free alkali-free glass prepared by the same, which is used to solve the problem that the existing alkali-free aluminosilicate glass has a large viscosity after melting.

The first aspect of the present application provides a phosphorus-free and alkali-free glass batch suitable for float molding, which comprises, by mass percentage, the following components:

In some embodiments of the first aspect of the present application, the content of B ₂ O ₃ is 6 to 7.5%.

The second aspect of the present application provides a method for preparing a float phosphorus-free alkali-free glass, including:

(1) a step of obtaining the glass batch of the first aspect;

(2) a step of heating the glass batch to a melting and clarifying temperature to obtain a clear glass liquid, the melting and clarifying temperature being 1630-1660 ° C;

and / or

(3) When the temperature of the molten glass is lowered to the molding starting temperature, it is poured into a tin bath to perform a float molding step, and the molding starting temperature is 1400 to 1430 ° C.

In some embodiments of the second aspect of the present application, it may further include step (4), and a step of annealing at 640-680 ° C.

In some embodiments of the second aspect of the present application, the operating temperature of the float molding is 1230-1260 ° C.

In some embodiments of the second aspect of the present application, in step (2), the melting and clarifying temperature is 1638-1658 ° C.

In some embodiments of the second aspect of the present application, in step (3), the molding start temperature is 1407 to 1421 ° C.

The third aspect of the present application provides a phosphorus-free and alkali-free glass suitable for float molding, which comprises, by mass percentage, the following components:

In some embodiments of the third aspect of the present application, the content of B ₂ O ₃ is 6 to 6.8%.

In some embodiments of the third aspect of the present application, the value of (MgO + CaO + SrO) / Al ₂ O ₃ is: 0.71 to 1.03.

In some embodiments of the third aspect of the present application, 0.34 ≦ MgO / CaO ≦ 0.78, and / or 0.03 ≦ GeO ₂ / SiO ₂ ≦ 0.16.

In some embodiments of the third aspect of the present application, the phosphorus-free and alkali-free glass does not contain As ₂ O ₃ and Sb ₂ O ₃ .

In some embodiments of the third aspect of the present application, the intrinsic viscosity point when the viscosity is 10 Pa · s is 1638 to 1658 ° C;

and / or

When the viscosity is 100 Pa · s, the intrinsic viscosity point is 1407 to 1421 ° C.

In some embodiments of the third aspect of the present application, the surface tension of the phosphorus-free and alkali-free glass at 1200 ° C. is 300 to 310 mN / m, and preferably 302 to 306 mN / m.

In some embodiments of the third aspect of the present application, the phosphorus-free and alkali-free glass has at least one of the following performance indicators:

Coefficient of linear thermal expansion: 3.63 × 10 ^-6 / ℃ ≤ linear thermal expansion coefficient ≤ 3.75 × 10 ^-6 / ℃ in the range of 25 ～ 350 ℃;

The density is 2.528 ～ 2.559g / cm ³ ;

Strain point is 670 ～ 680 ℃;

The annealing point is 724 ～ 732 ℃;

Softening point of dead weight is 970 ～ 980 ℃;

Young's modulus is 74 ～ 78GPa;

Shear modulus is 30 ～ 32GPa;

Poisson's ratio is 0.21 to 0.24.

In some embodiments of the third aspect of the present application, the phosphorus-free and alkali-free glass has an average visible light transmittance of 90 to 91% when the visible light is 380 to 800 nm and the thickness is 2 mm.

In some embodiments of the third aspect of the present application, the thickness of the phosphorus-free and alkali-free glass is 0.5-1.5 mm.

As can be seen from the above technical solution, a phosphorus-free and alkali-free glass batch material suitable for float molding and a phosphorus-free and alkali-free glass prepared by the application are provided. Optimization, including but not limited to adding an appropriate amount of GeO ₂ to the composition, effectively reduces the viscosity of the alkali-free aluminosilicate glass after melting, thereby reducing the requirements for glass production equipment and reducing costs;

Further, by adding appropriate amounts of MoO ₃ and WO _{3 to the} glass component, the surface tension of the alkali-free aluminosilicate glass after melting is reduced; it is more beneficial to the molding of glass, especially flexible glass.

Detailed ways

Through research, the inventors of this application have unexpectedly found that by introducing GeO ₂ , the viscosity of the glass after melting can be effectively reduced. The analysis is because the melting point of GeO ₂ is much smaller than that of SiO ₂ and the viscosity of the GeO ₂ melt The activation energy is small, so that the viscosity of the glass decreases after melting at high temperature; but the inventors further found that excess GeO ₂ will increase the density of the glass, and GeO ₂ may change the network structure to make the strain point, annealing point and softening point The negative impact on the glass performance index; comprehensive consideration of the advantages and disadvantages that may be brought by the introduction of GeO ₂ and taking into account the reduction of the difficulty of glass preparation process and the improvement of performance indicators, under the premise of this In the technical solution provided by the application, the mass percentage of GeO ₂ contained in the phosphorus-free alkali-free glass batch and / or the phosphorus-free alkali-free glass is 2-8%.

When glass is formed by the float method, there are two kinds of forces, namely its own gravity and surface tension; its own gravity promotes the spread of the glass liquid, and the surface tension prevents the glass liquid from spreading out infinitely. When the two are balanced, they float in the tin liquid. The glass ribbon can be formed in a natural thickness. When the surface tension is large, it is often difficult to obtain thinner glass; this has a particularly significant impact on the molding of ultra-thin flexible glass, and the surface shrinkage caused by glass surface tension brings difficulties to the molding of flexible glass. In order to solve this problem, the inventors found through extensive research that introducing a small amount of MoO ₃ and WO ₃ into the composition of the glass can effectively reduce the surface tension of the glass liquid; thereby facilitating the molding of ultra-thin flexible glass. In the technical solution of the present application, when the total content of MoO ₃ and WO ₃ contained in the alkali-free glass batch and / or the phosphorus-free alkali-free glass is between 0.2 and 0.5%, the glass liquid can be reduced. The effect of surface tension, while not increasing the density of the glass; in line with the trend of lightweight glass flexible development. However, once the total content of MoO ₃ and WO ₃ is less than 0.2%, such as 0.1%, the decrease in the surface tension of the glass is not significant. Whereas the sum of the contents of MoO ₃ and WO ₃ is greater than 0.5%, for example, 0.7%, the density of the glass increases significantly, which is undesirable.

The inventors further found that the simultaneous introduction of MoO ₃ and WO ₃ into the glass composition is more effective than the introduction of either of them separately.

SiO ₂ is the main component constituting the glass network. The higher the SiO ₂ content, the higher the strain point of the glass, but at the same time the high temperature viscosity of the glass will increase. If the SiO _{2 is} too much, it will be difficult to obtain a glass with long material properties. If the SiO ₂ content is low, it is not easy to form glass, the strain point is reduced, and the expansion coefficient is increased. Taking into account the melting temperature, the crystallization upper limit temperature, the glass expansion coefficient, the strain point, and the frit properties, etc., in the technical solution of this application The content of SiO ₂ contained in the alkali-free glass batch and / or the phosphorus-free alkali-free glass is 49.5% to 59.5%.

B ₂ O ₃ can also reduce the viscosity of the glass liquid, and it can also reduce the expansion coefficient of the glass. In the technical solution of the present application, the suitable range of B ₂ O ₃ contained in the phosphorus-free and alkali-free glass is 6 to 7.5. %, Or 6 to 6.8%. Considering the B ₂ O ₃ volatilization at high temperatures, the alkali-free glass batch preferable range of B ₂ O ₃ is from 6 to 8.3%, or from 6 to 7.5%.

Al ₂ O ₃ enters the glass network in the form of [AlO ₄ ] tetrahedron and plays a role in repairing the broken network, which is conducive to enhancing the density of the glass network structure and increasing the characteristic viscosity point of the glass. In the technical solution of this application, no A suitable range of Al ₂ O ₃ contained in the alkali glass batch and / or the phosphorus-free and alkali-free glass is 15 to 19.1%.

ZrO ₂ Zr ⁴⁺ at a high temperature into the form of a network coordination number of four, it has the same as Si ⁴⁺ laid action, ZrO ₂ may be added a suitable amount of a dense network structure of the glass, but excessive ZrO ₂ will make the glass viscosity increases In the technical solution of the present application, a suitable range of ZrO ₂ contained in the alkali-free glass batch and / or the phosphorus-free alkali-free glass is 0.1 to 0.3%.

MgO can reduce the high-temperature viscosity of the glass, increase the low-temperature viscosity, and also increase the strain point of the glass. In the technical solution of this application, the content of MgO contained in the alkali-free glass batch and / or phosphorus-free alkali-free glass is 2 ～ 3.8%, if the content is greater than 3.8%, the decrease in high temperature viscosity may cause the liquidus temperature of the glass to increase, and the linear thermal expansion coefficient will also decrease.

CaO and MgO have similar effects, and can also reduce the high temperature viscosity of the molten glass. In the technical solution of the present application, the suitable range of CaO contained in the alkali-free glass batch and / or phosphorus-free alkali-free glass is 3.7 to 6%. The effect of SrO is similar, and a suitable range is 6 to 7%.

SnO is used to eliminate bubbles in the glass liquid. In the technical solution of the present application, the suitable range of SnO contained in the alkali-free glass batch and / or phosphorus-free alkali-free glass is 0.05 to 0.3%.

The ingredients of the phosphorus-free and alkali-free glass according to the first aspect of the present application and the phosphorus-free and alkali-free glass according to the third aspect, each component contained therein can be introduced through a mineral raw material substantially free of alkali, or through a chemical raw material Introduce

Illustratively, in some embodiments of the present application, silica, aluminum oxide, germanium dioxide, zirconium dioxide, magnesium oxide, calcium carbonate, strontium carbonate, boric acid, stannous oxide, and tungsten trioxide can be passed through , Molybdenum trioxide and other compounds to introduce the corresponding components.

In other embodiments of the present application, SiO ₂ may be introduced through quartz sand (the amount of impurities Fe \ K \ Na is controlled at a qualified level); GeO _{2 may} be introduced through a high-purity chemical raw material inorganic germanium powder; and aluminum hydroxide (purity 99.5% or more) introduction of Al ₂ O ₃ ; introduction of B ₂ O ₃ through boric acid; introduction of CaO through purified heavy calcium carbonate; introduction of SrO through high-purity strontium carbonate; other components with less content, such as ZrO ₂ , SnO, MoO ₃ and WO ₃ can be introduced directly through chemical raw materials.

In some embodiments of the present application, the phosphorus-free and alkali-free glass according to the third aspect may be prepared from the phosphorus-free and alkali-free glass batch according to the first aspect. The components and contents of the phosphorus-free and alkali-free glass are basically the same as those of the batch, except for the individual volatile components. After melting at high temperature, the content of the phosphorus-free and alkali-free glass is relative to that The content will be reduced; for example, B ₂ O ₃ will lose about 10% after melting at high temperature. It should be noted that the volatility of each component and the degree of volatility are well known to those skilled in the art.

In the method for preparing a float phosphorus-free alkali-free glass according to the second aspect of the present application, in step (2), the temperature of the batch can be raised from room temperature to 1000 ° C. at a heating rate of 5-10 ° C./min. Then, the temperature is increased from 1000 ° C to a temperature of 1630-1660 ° C (melting and clarifying temperature) at a temperature increase rate of 2-5 ° C / min; and the temperature is maintained at this temperature for 1-4 hours for clarification of the glass liquid.

The testing of various performance indicators of the glass involved in this application, the testing standards on which it is based, and the instruments used are shown in Table 1 below.

Table 1

definition

In the present application, "SiO ₂ + GeO ₂ " means the sum of the mass percentages of SiO ₂ and GeO ₂ .

Similarly, “SiO ₂ + Al ₂ O ₃ + ZrO ₂ ” represents the sum of the mass percentages of the three of SiO ₂ , Al ₂ O ₃ , and ZrO ₂ .

In the present application, “(MgO + CaO + SrO) / Al ₂ O ₃ ” means the ratio of the sum of the mass percentages of (MgO + CaO + SrO) to the mass percentage of Al ₂ O ₃ . Similarly, "MgO / CaO" means the ratio of the mass percentage of MgO to the mass percentage of CaO. "GeO ₂ / SiO ₂ " means a ratio of the mass percentage of GeO _{2 to} the mass percentage of SiO ₂ .

In the present application, "mineral raw materials" can be understood as natural mineral raw materials, which have the characteristics of complex components and more impurities, such as quartz sand, clay, feldspar and limestone.

In the present application, "chemical raw materials" can be understood as chemically purified raw materials with high purity and few impurities, such as aluminum hydroxide, zinc oxide, boric acid, and the like.

In the present application, "base-free" or "base-free" means that it is substantially free of alkali metal oxides such as Na ₂ O, K ₂ O, and Li ₂ O.

In this application, the "intrinsic viscosity point" refers to the temperature value when the glass reaches a certain viscosity.

It can be understood that when the characteristic viscosity point of a glass at a certain viscosity decreases, it can be determined that the viscosity of the glass is reduced.

In the present application, "glass liquid" is sometimes referred to as "melted glass" and both have the same meaning.

In the present application, the "operating temperature" refers to the working temperature of the edger during the thinning operation by the edger after the molten glass liquid enters the tin bath from the melting furnace when the glass is formed by the float method.

In order to make the purpose, technical solution, and advantages of the present application clearer and clearer, the present application is further described in detail below through specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in this application, all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

Example 1

Weigh the appropriate batch according to the composition of the phosphorus-free and alkali-free glass in Table 2. Then put the weighed batch into the melting furnace, and raise the batch from room temperature to 1000 ° C at a heating rate of 8 ° C / min. ; Then raise the temperature from 3O0C / min from 1000 to 1638 ° C (corresponding to the viscosity of the glass liquid of 10Pa · s); hold at the melting and clarifying temperature for 2 hours to obtain a clear glass liquid;

When the temperature of the molten glass is lowered to 1407 ° C (corresponding to the viscosity of the molten glass of 100Pa · s), the molten glass is allowed to enter a tin bath, and float molding is performed at an operating temperature of 1236 ° C;

The formed glass is annealed at an annealing temperature of 650 ° C. After being held at the annealing temperature for 1 hour, it is cooled to room temperature; a phosphorus-free and alkali-free glass having a thickness of 1 mm is obtained; the process parameters during the preparation process and the phosphorus-free and 1 mm-thickness The performance indexes of the alkali glass are all shown in Table 2.

Examples 2-8

According to the preparation method of the float glass described in Example 1, the phosphorus-free and alkali-free glass composition and process parameters described in Table 2 were used to prepare a phosphorus-free and alkali-free glass with a thickness of 1 mm; and the prepared 1 mm phosphorus-free and alkali-free glass The performance index of glass is shown in Table 2.

Table 2

Comparative Examples 1-7

According to the method for preparing the float glass described in Example 1, a glass having a thickness of 1 mm was prepared by using the glass composition and process parameters described in Table 3;

table 3

Composition of a commercially available alkali-free aluminosilicate flexible glass of Comparative Example 1; from the data in Table 2-3, it can be seen that the glass component of Comparative Example 1 does not contain GeO ₂ , MoO ₃ and WO ₃ At the same time, compared with Comparative Example 1, the melting and clarification temperature, the molding start temperature, the operating temperature, and the surface tension of Examples 1-8 of the present application are significantly reduced, which fully illustrates:

(1) After adding an appropriate amount of GeO _{2 to the} glass composition, the intrinsic viscosity point of the glass decreases, that is, the viscosity of the glass decreases; the melting and clarification temperature, the molding start temperature, and the operating temperature corresponding to the glass also decrease accordingly. In view of this, using the alkali-free glass composition provided in the present application to prepare glass can reduce equipment requirements and reduce costs in the float molding process; in addition, lowering the temperature will also make the molding process easier to control.

(2) Adding MoO ₃ and WO _{3 to the} glass composition can effectively reduce the surface tension of the glass; therefore, it is easier to form ultra-thin flexible glass.

In addition, compared with Comparative Examples 2-3, it can be seen that GeO ₂ below 2% cannot significantly reduce the viscosity of the glass; while GeO ₂ above 8% can effectively reduce the viscosity of the glass, but it will As a result, performance indicators such as the strain point, annealing point and softening point of the glass are reduced, and the performance of the glass is reduced.

It can be seen from Comparative Examples 4-5 that when the sum of the contents of MoO ₃ and WO ₃ is too small, for example, 0.1%, the degree of reduction in the surface tension of the glass (compared to Comparative Example 1) is significantly lower than that of MoO ₃ and WO ₃ Examples whose total content is greater than 0.2%. However, the sum of the contents of MoO ₃ and WO ₃ is too large. For example, when 0.7%, the density of glass increases significantly, which is undesirable.

More surprisingly, it can be seen from Comparative Examples 6-7 that when 0.35% MoO ₃ or WO ₃ is introduced alone, the surface tension of the alkali-free glass prepared is 305-307 mN / m; while Example 6 is simultaneously The introduction of MoO ₃ and WO ₃ (the sum of 0.35%) and the surface tension is 302 mN / m; it can be seen that the simultaneous introduction of MoO ₃ and WO ₃ into the glass composition is better than introducing one of the two separately. Reduces surface tension more significantly.

The above are only preferred embodiments of this application, and are not intended to limit this application. Any modification, equivalent replacement, or improvement made within the spirit and principle of this application shall be included in this application Within the scope of protection.

Claims

A phosphorus-free and alkali-free glass batch suitable for float molding, characterized in that, in terms of mass percentage, it contains the following components:
The phosphorus-free and alkali-free glass batch according to claim 1, wherein the content of B 2 O 3 is 6 to 7.5%.
A method for preparing float-free phosphorus-free alkali-free glass, comprising:

(1) a step of obtaining the glass batch according to claim 1 or 2;

(2) a step of heating the glass batch to a melting and clarifying temperature to obtain a clear glass liquid, the melting and clarifying temperature being 1630-1660 ° C;

and / or

(3) When the temperature of the molten glass is lowered to the molding starting temperature, it is poured into a tin bath to perform a float molding step, and the molding starting temperature is 1400 to 1430 ° C.
The method for preparing a float phosphorus-free alkali-free glass according to claim 3, further comprising a step (4) of performing an annealing step at 640-680 ° C.
The method for preparing a float-free phosphorus-free alkali-free glass according to claim 3 or 4, wherein the operating temperature of the float-forming process is 1230-1260 ° C.
A phosphorus-free and alkali-free glass suitable for float molding, characterized in that, in terms of mass percentage, it contains the following components:
The non-phosphorus and alkali-free glass according to claim 6, wherein the content of B 2 O 3 is 6 to 6.8%.
The phosphorus-free and alkali-free glass according to claim 6 or 7, wherein a value of (MgO + CaO + SrO) / Al 2 O 3 is: 0.71 to 1.03.
The phosphorus-free and alkali-free glass according to any one of claims 6 to 8, characterized in that 0.34≤MgO / CaO≤0.78, and / or 0.03≤GeO 2 / SiO 2 ≤0.16.
The phosphorus-free and alkali-free glass according to any one of claims 6 to 9, characterized in that the phosphorus-free and alkali-free glass does not contain As 2 O 3 and Sb 2 O 3 .
The phosphorus-free and alkali-free glass according to any one of claims 6 to 10, wherein the intrinsic viscosity point at a viscosity of 10 Pa · s is 1638 to 1658 ° C;

and / or

When the viscosity is 100 Pa · s, the intrinsic viscosity point is 1407 to 1421 ° C.
The phosphorus-free alkali-free glass according to any one of claims 6 to 11, characterized in that the surface tension of the phosphorus-free alkali-free glass at 1200 ° C is 300 to 310 mN / m, preferably 302 to 306 mN / m .
The phosphorus-free alkali-free glass according to any one of claims 6 to 12, wherein the phosphorus-free alkali-free glass has at least one of the following performance indicators:

Coefficient of linear thermal expansion: 3.63 × 10 -6 / ℃ ≤ linear thermal expansion coefficient ≤ 3.75 × 10 -6 / ℃ in the range of 25 ～ 350 ℃;

The density is 2.528 ～ 2.559g / cm 3 ;

Strain point is 670 ～ 680 ℃;

The annealing point is 724 ～ 732 ℃;

Softening point of dead weight is 970 ～ 980 ℃;

Young's modulus is 74 ～ 78GPa;

Shear modulus is 30 ～ 32GPa;

Poisson's ratio is 0.21 to 0.24.
The phosphor-free and alkali-free glass according to any one of claims 6 to 13, wherein the phosphor-free alkali-free glass has an average visible light transmittance at a thickness of 2 mm under visible light irradiation at 380 to 800 nm. 90 to 91%.
The phosphorus-free and alkali-free glass according to any one of claims 6 to 14, wherein the thickness of the phosphorus-free and alkali-free glass is 0.5 to 1.5 mm.