Glass composition for barrier fibers and method for producing such fibers

Abstract

To minimize, or even eliminate, the use of sodium carbonate in a glass recipe, including a mixture of raw materials for the manufacture of glass wool, while retaining the main properties of glass necessary for the barrier properties of glass wool. [Solution] A glass composition for barrier fibers, comprising, by mass percent: SiO2: 62.0%~65.0%, Na2O: 14.0~15.5%, CaO: 6.0~9.0%, MgO: 1.5~4.0%, B2O3: 5.5~7.5%, Al2O3: 1.5~2.5%, K2O: 0~2.0%, one or more other oxides: cumulatively 0~5.0% by weight, preferably cumulatively 0~2.0% by weight, and having a Na2O / B2O3 ratio between 1.90 and 2.80; a glass composition; barrier fibers obtained from the composition; and a method for producing such fibers.

Description

[Technical Field]

[0001] The present invention relates to the manufacture of barrier mineral wool, particularly glass wool. More specifically, the present invention relates to the optimization of the formulation of the final glass composition and the raw material mixture (or recipe) used in its manufacture, with the aim of preserving its essential properties by enabling the extensive use of recycled materials, particularly float glass, borosilicate glass, or packaging glass (bottle) cullet.

[0002] The present invention relates to the field of melting a mixture of raw materials for the manufacture of glass wool, which is particularly used in the field of thermal insulation (heat shielding) and / or soundproofing (acoustic shielding) of buildings and the like. [Background technology]

[0003] Currently, sodium carbonate (often referred to as soda ash in the literature) is widely used as a sodium carrier (= a raw material that provides the sodium element in the final glass matrix) for the manufacture of insulating glass fibers. [Overview of the project] [Problems that the invention aims to solve]

[0004] Currently, particularly in the field of insulating glass manufacturing, glass wool manufacturers desire, for various reasons, to reduce the amount of sodium carbonate required for glass production, or even to eliminate its use altogether: - Soda ash is highly hygroscopic: even batches containing small amounts of soda ash tend to solidify in temporary storage silos, which creates process problems and hazardous washing procedures. - Soda ash contributes significantly to greenhouse gas (CO2) emissions.

[0005] In particular, according to the first major drawback, during the melting of the glass composition thus formed, the carbonate reacts in the glass to produce CO2, resulting in a bubbling phenomenon. Furthermore, the extraction, production, and / or transportation of soda ash generates significant CO2 emissions. Finally, the soda ash market can be limited in supply, and the price of sodium carbonate can be relatively high and volatile. [Means for solving the problem]

[0006] According to a first aspect, the present invention makes it possible to minimize, or even eliminate, the use of sodium carbonate in a glass recipe containing a mixture of raw materials for the manufacture of glass wool, while retaining the main properties of glass necessary for the barrier properties of the glass wool. [Modes for carrying out the invention]

[0007] A favorable way to minimize the carbonate content, particularly sodium carbonate, in such recipes is to increase the proportion of recycled materials (float glass cullet, bottle cullet, borosilicate glass, mineral wool, and especially waste from the manufacture of glass wool) according to this recipe. However, the glass matrix of float cullet (i.e., derived from recycled flat glass used in the construction industry) and bottle cullet or borosilicate glass differs considerably from the chemical properties of barrier glass. The latter, for example, has a relatively low silica content, and therefore there is an upper limit to the proportion of this cullet that can be used in this recipe.

[0008] Conventional cullet compositions for flat glass and bottle glass are shown in Table 1 below:

[0009] [Table 1]

[0010] Assuming that the silica content of float glass and packaging glass is approximately 72% by weight on average, and that the silica content of insulating glass wool is approximately 64% by weight, a theoretical upper limit of 64 / 72 = 89% can be assumed for the use of flat glass cullet in a typical glass wool manufacturing recipe. For other reasons, such as the presence of silica in the raw materials (feldspar, oxidizing agent) required for the manufacture of insulating glass, the upper limit can be set at 85% by weight.

[0011] When using such large quantities of cullet, the barrier glass recipe also advantageously does not contain silica sand (which is a resource under pressure), nor even calcium and magnesium supports, which are likely to be carbonated.

[0012] Therefore, a further object of the present invention is to provide a glass composition for inorganic barrier fibers adapted to enable the use of the maximum amount of flat glass cullet or packaging (bottle) glass cullet.

[0013] The glass used as a barrier in glass wool today generally has a higher alumina, boron, and sodium content than float glass and packaging glass. As a result, in addition to recycled materials, the rest of the batch (raw materials, natural or synthetic) can provide other important elements, particularly in relation to the manufacture of glass wool: - Aluminum (for example, introduced as a raw material in the form of feldspar, nepheline, phonolite, etc.) - Boron (for example, introduced as a raw material in the form of borax hydrate, boric acid, kerite, etc.) - Optionally, a non-carbonate form of sodium (such as sodium hydroxide (NaOH), sodium silicate, sodium nitrate, or sodium sulfate).

[0014] Alumina and boron carriers generally do not contain carbonates, but this is not the case for sodium carriers. Some studies have suggested exchanging sodium carbonate with sodium-containing non-carbonates such as sodium nitrate or sodium sulfate mentioned above. These materials have many drawbacks, such as their properties (hygroscopicity, corrosiveness, explosiveness), and risks associated with the release of gases and pollutants (NOx, SOx). Furthermore, such use may require fundamental changes in processing equipment, mixing, conveying, and / or melting technologies. Therefore, these alternative materials should be minimized in this recipe.

[0015] The following describes the basic properties used in the molten glass composition useful for fiber glass fiberization: - The temperature corresponding to a viscosity of 1000 poises, denoted as "T log3 ", expressed in degrees Celsius, corresponding to a typical fiberization temperature; - The liquidus temperature, denoted as "T liq " or referred to as T liquidus, corresponding to the temperature below which the first crystals can form.

[0016] For the correct implementation of the fiberization method, it is important to limit the liquidus temperature T liq of the glass being produced, so as not to have to raise the temperature of the molten glass in the fiberization dish, thereby avoiding the presence of crystals that would interfere with the glass-forming process. An increase in T liq leads especially to additional energy costs and reduces the service life of the dish used for fiberization and / or the quality of the final product. Also, if the temperature of the glass is below T liq when passing through the fiberization tool, especially in a perforated dish, there is a risk of clogging the calibrated holes of this part due to crystallization.

[0017] Furthermore, the forming margin, i.e., the production by stretching the fibers, is between T log3 and T liqIt can be carried out in a temperature range corresponding to the difference therebetween (denoted as “ΔT” and expressed in degrees Celsius). The larger this difference is, the more fiberization methods can be implemented under the conditions of avoiding the aforementioned drawbacks.

[0018] The use of a large amount of cullet for the production of glass fibers for insulation, in particular, more than 60%, or even more than 70%, or even more than 75%, or even more than 80% of the cullet of the mass of molten glass (excluding internal recycled cullet) enabling the above production, is an object of the present invention.

[0019] The object of the present invention is, in particular, to enable the use of a very large amount of cullet without causing the risk of clogging of the fiberization equipment through premature crystallization of the molten glass in the fiberization equipment when T liq is too high and / or the forming margin is too narrow, and to provide a glass composition and related method.

[0020] This use has become possible by adapting the composition of the target glass to introduce a large amount of cullet into the melt according to the present invention.

[0021] According to the present invention, by specifically adapting the molten glass composition and by selecting raw materials from the list described below in a vitrifiable mixture, it has been found that it is possible to maintain the liquidus temperature of a raw material mixture rich in silica and having a very large amount of cullet at a temperature of 920 °C or lower and to maintain the forming margin above 120 °C.

[0022] Therefore, the present invention proposes an optimization of the final oxide content of the glass while maintaining the properties of the glass, and also proposes a raw material selection method that minimizes or avoids the use of sodium carbonate or more generally a soda carrier in this recipe.

[0023] The mass fraction of Na2O contributed by the sodium carrier in the glass matrix can be calculated according to the following formula:

[0024]

Number

[0025] m 担体 is the mass of the carrier in the recipe, and the mass of the glass m ガラス occurs, and f Na2O is the mass fraction of Na2O in the target carrier. The mass fraction of Na2O contributed by all sodium carriers is the sum of all the mass fractions of Na2O contributed by each sodium carrier.

[0026] An object of the present invention is, in particular, a glass composition that can be used as a barrier fiber, which contains more than 70% by weight of SiO2 and preferably does not require one or more carbonates and particularly does not contain sodium carbonate, and can be manufactured using more than 70% by weight of glass cullet as a raw material, to provide a glass composition.

[0027] More precisely, according to the first object, the present invention relates to a glass composition for barrier fibers having the following composition and to such glass fibers: SiO2: between 62.0% and 65.0%, Na2O: between 14.0 and 16.0%, preferably between 14.0 and 15.5% CaO: between 6.0 and 9.0%, MgO: between 1.5 and 4.0%, B2O3: between 5.5 and 7.5%, Al2O3: between 1.5 and 2.5%, K2O: between 0 and 2.0%, One or more other oxides: in total between 0 and 5.0% by weight, The Na2O / B2O3 ratio is between 1.90 and 2.80.

[0028] According to another advantageous embodiment of the composition according to the present invention, the following are provided, and these can be combined with each other if appropriate: - The Na2O / B2O3 ratio is 2.10 to 2.50, preferably 2.10 to 2.40, and more preferably 2.10 to 2.30. - The mass percentage of Na2O is 14.5-15.5%. - The mass percentage of B2O3 is 6.5-8.0%, more preferably 6.7-7.5%. - The mass percentage of Al2O3 is 1.6-2.0%. - The mass percentage of SiO2 is 63.0-64.0%. - The mass percentage of MgO is 2.5-3.5%. - The mass percentage of CaO is 8.0-9.0%. - The glass composition is heated to 1030-1080°C. log3 It has a value, T log3 10 of the molten composition 3 This temperature corresponds to the viscosity of Poise. - The glass composition is suitable for temperatures below 925°C, preferably below 920°C. liq It has a value, T liq This is the temperature below which the first crystals form when the molten composition cools. - The glass composition is at a temperature of over 100°C, preferably over 110°C, and its T log3 and T liq It has a difference ΔT.

[0029] The present invention also relates to glass fibers corresponding to the above-mentioned compositions, comprising glass fibers obtained by melting and fibrousizing the compositions, and glass fiber mats comprising aggregates of such glass fibers bound together by organic or inorganic binders.

[0030] The present invention also relates to a method for producing the glass fibers having the above composition, the method comprising melting a mixture of raw materials constituting a molten material and fibrousizing the molten material, the molten material being: - Glass cullet having more than 70%, preferably more than 71% by weight of silica, - At least one aluminum source - At least one source of boron (boron source), - Optionally, at least one source of magnesium (magnesium source), - Optionally, at least one sodium source, preferably selected from sodium hydroxide (NaOH), sodium silicate, sodium nitrate, or a mixture thereof; - Optionally, at least one source of calcium, - Optionally, a source of at least one element selected from phosphorus (P), manganese (Mn), iron (Fe), and fluorine (F). Includes, The above glass cullet is more than 70% by mass, preferably more than 75% by mass, of the molten glass obtained from the mixture of raw materials constituting the molten material.

[0031] According to an advantageous embodiment of the method according to the present invention: - A quantity of one or more sources of sodium and boron is introduced into the raw material mixture such that the Na2O / B2O3 ratio in the above target composition is 1.90 to 2.80, preferably 2.10 to 2.50, more preferably 2.10 to 2.40, or even more preferably 2.10 to 2.30. - One of the boron sources or the boron source is selected from boron oxides such as boric acid, or mixed oxides of boron with at least one element selected from the group consisting of Si, Mg, Ca, and Na, and is particularly selected from oxides selected from the group consisting of anhydrous borax or borax pentahydrate, natural or synthetic colemanite, optionally calcined ulexite, hydroboracite, razorite, conite or kernite, and mixtures thereof. - One of the boron sources, or a boron source in general, is borax pentahydrate. - One of the aluminum sources, or an aluminum source, is selected from a mixed oxide of aluminum with at least one element selected from the group consisting of Si, Ca, Na, and K, and in particular from aluminum silicates and mixed oxides of aluminum with at least one element selected from the group consisting of Ca, Na, or K, or from hydrate (Al(OH)3) or calcined alumina Al2O3, feldspar with a common composition (K,Na)AlSi3O8, or phonolite with a common composition 4SiO2.Al2O3.0.5(Na2O.K2O), or nepheline with a common composition 4SiO2.Al2O3.0.5(Na2O.K2O). - The raw material mixture preferably further comprises a calcium source (source of calcium) selected from the group consisting of lime, for example, quicklime or slaked lime, or limestone. - In addition to the cullet mentioned above, the mixture of raw materials may optionally contain only oxides in hydrate form. - At least a portion of the above glass cullet originates from float glass. - At least a portion of the above glass cullet is derived from borosilicate glass. - At least a portion of the above glass cullet originates from bottle glass. [Examples]

[0032] The following examples illustrate the advantages of the present invention.

[0033] In these embodiments, two glass compositions for barrier fibers are compared.

[0034] The glass composition in Example 1 is a comparative example, while the glass composition in Example 2 conforms to the present invention.

[0035] The target formulations are shown in Table 2 below:

[0036] [Table 2]

[0037] All types of glass are obtained from the initial raw materials shown in Table 3 below:

[0038] [Table 3]

[0039] Table 4 below shows the oxide composition of the raw materials used:

[0040] [Table 4]

[0041] It can be shown that the target glass according to Example 1 cannot be obtained without the addition of a substantial amount of sodium carbonate, given the use of such proportions of float glass or bottle glass in the initial raw material recipe, and flat glass or bottle glass cullet contains significantly less sodium by mass fraction than the typical target, with respect to the barrier glass. In contrast, the prepared target glass according to the present invention can be obtained without the use of a specific sodium support.

[0042] The properties of the two types of glass are shown in Table 5 below:

[0043] [Table 5]

[0044] It can be seen that the glass composition according to the present invention satisfies all of the above-described principles. Adjusted glass has advantages: - T log3 and T liq The value is close to that of the reference glass (with a difference of 5°C or less), and this ensures all the necessary safety in the fiberization process, as the difference between these two values ​​remains greater than 120°C. - The amount of alumina is maintained at a value close to 2% by mass, which ensures the biosolubility of the fibers produced.

[0045] Furthermore, a higher boron content increases the ability of the final product to scatter IR light, thereby increasing its adiabatic properties.

[0046] Finally, the composition for the insulating glass fiber and the method for obtaining it make the following possible: - In the initial raw material recipe, a very large amount of glass cullet of different compositions, especially float glass cullet, borosilicate glass cullet, or other bottled glass cullet is used. - In the first recipe, minimize the amount of sodium source required, especially in the form of carbonate, in relation to such a proportion of glass cullet. - Maintaining the appropriate viscosity of the glass at the fiberization temperature. - To enable such fiber formation without increased difficulty, maintain a sufficiently low liquidus temperature. - Maintain the bio-soluble properties of glass wool manufactured according to current standards. - Or even further, by improving the diffusion of light through the glass fiber (for example, by increasing the boron content).

[0047] According to further advantages relating to specific embodiments of the present invention, the carbonate-free boron and alumina support is selected to introduce the maximum amount of sodium, for example, borax pentahydrate (instead of boric acid) and / or sodium feldspar (instead of potassium feldspar and / or mixed feldspar).

Claims

1. Glass composition for insulating fibers, in mass percent: Yes ２ :62.0%~65.0%, Na ２ O:14.0~15.5%、 CaO: 6.0-9.0%, MgO: 1.5-4.0%, B ２ O ３ :5.5~7.5%、 Al ２ O ３ :1.5~2.5%、 K ２ O: 0~2.0%, One or more other oxides: 0 to 5.0% by weight in total, preferably 0 to 2.0% by weight in total. It contains, Na ２ O / B ２ O ３ The ratio is 1.90 to 2.80, Glass composition.

2. Na ２ O / B ２ O ３ The glass composition according to claim 1, wherein the ratio is 2.10 to 2.50, preferably 2.10 to 2.

40.

3. Na ２ The glass composition according to claim 1 or 2, wherein the mass percentage of O is 14.5 to 15.5%.

4. B ２ O ３ The glass composition according to any one of claims 1 to 3, wherein the mass percentage of is 6.5 to 8.0%, more preferably 6.7 to 7.5%.

5. Al ２ O ３ The glass composition according to any one of claims 1 to 4, wherein the mass percentage of is 1.6 to 2.0%.

6. SiO ２ The glass composition according to any one of claims 1 to 5, wherein the mass percentage of is 63.0 to 64.0%.

7. A glass composition according to any one of claims 1 to 6, wherein the mass percentage of MgO is 2.5 to 3.5%.

8. The glass composition according to any one of claims 1 to 7, wherein the mass percentage of CaO is 8.0 to 9.0%.

9. T 1030-1080°C ｌｏｇ３ It has a value, T ｌｏｇ３ 10 of the molten composition ３ A glass composition according to any one of claims 1 to 8, wherein the temperature corresponds to the viscosity of the poise.

10. T below 925°C, preferably below 920°C ｌｉｑ It has a value, T ｌｉｑ The glass composition according to any one of claims 1 to 9, wherein is the temperature below which the first crystals are formed when the molten composition is cooled.

11. T ｌｏｇ３ Value and T ｌｉｑ The glass composition according to any one of claims 1 to 10, wherein the difference ΔT between the value and the specified value is greater than 100°C, preferably greater than 110°C.

12. A glass fiber for barrier purposes, corresponding to the composition described in any one of claims 1 to 11.

13. A glass fiber mat comprising an aggregate of glass fibers as described in claim 12, bound together by an organic or inorganic binder.

14. A method for producing glass fibers according to claim 12, comprising the composition according to any one of claims 1 to 11, This includes melting a mixture of raw materials constituting a molten product, and fibrousizing the molten mixture. The aforementioned molten material is: - Glass cullet containing more than 70%, preferably more than 71% by weight of silica, - At least one source of aluminum, - At least one source of boron, - Optionally, at least one source of magnesium, - Optionally, at least one sodium source selected from sodium hydroxide (NaOH), sodium silicate, sodium nitrate, or a mixture thereof; - Optionally, at least one source of calcium, - Optionally, a source of at least one element selected from phosphorus (P), manganese (Mn), iron (Fe), and fluorine (F), Includes, The glass cullet comprises, by mass, more than 70%, preferably more than 75%, of the molten glass obtained from the mixture of raw materials constituting the molten material. method.

15. Na ２ O / B ２ O ３ A method for producing glass fibers according to claim 14, wherein amounts of one or more sources of sodium and boron are introduced into the raw material mixture in such an amount that the ratio in the target composition is 1.90 to 2.80, preferably 2.10 to 2.50, and more preferably 2.10 to 2.

40.

16. A method for producing glass fibers according to claim 14 or 15, wherein the source of boron is selected from boron oxides such as boric acid, or mixed oxides of boron with at least one element selected from the group consisting of Si, Mg, Ca, and Na, and in particular from anhydrous borax or pentahydrate borax, natural or synthetic colemanite, optionally calcined urexite, hydroborasite, lazolite, tin ore (conite) or kernite, and mixtures thereof.

17. A method for producing glass fibers according to any one of claims 14 to 16, wherein the boron source is borax pentahydrate.

18. The aluminum source is selected from a mixed oxide of aluminum and at least one element selected from Si, Ca, Na, and K, and in particular, aluminum silicate, and a mixed oxide or hydrate (Al(OH)) of aluminum and at least one element selected from Ca, Na, or K. ３ ), or calcined alumina Al ２ O ３ , Common composition (K,Na)AlSi ３ O ８ Feldspar, or for example, a typical composition of 4SiO ２ Al ２ O ３ 0.5 (Na ２ O.K. ２ O) Phonolite, or for example, a common composition 4SiO ２ Al ２ O ３ 0.5 (Na ２ O.K. ２ A method for producing glass fibers according to any one of claims 14 to 17, wherein the oxide is selected from the group consisting of nepheline (O).

19. The method for producing glass fibers according to any one of claims 14 to 18, wherein the raw material mixture further comprises a calcium source preferably selected from the group consisting of lime, such as quicklime or slaked lime, or limestone.

20. A method for producing glass fibers according to any one of claims 14 to 19, wherein the mixture of raw materials optionally includes only oxides in the form of hydrates, in addition to the cullet.

21. A method for producing glass fibers according to any one of claims 14 to 20, wherein at least a portion of the glass cullet is derived from float glass.

22. A method for producing glass fibers according to any one of claims 14 to 21, wherein at least a portion of the glass cullet is derived from borosilicate glass.

23. A method for producing glass fibers according to any one of claims 14 to 22, wherein at least a portion of the glass cullet is derived from bottle glass.

Images