A high modulus glass fiber composition

Abstract

The invention relates to a high modulus glass fiber composition. The glass fiber composition contains, by weight percentage, 50-70% SiO2, 15-25% Al2O3, 5-15% CaO, 5-15% MgO, 0,5-5% B2O3, and 0,5-1, 5% Na2O.

Description

[0001] A HIGH MODULUS GLASS FIBER COMPOSITION

[0002] TECHNICAL FIELD

[0003] The present invention relates to a high modulus glass fiber composition.

[0004] BACKGROUND ART

[0005] Glass fibers manufactured for use in composite applications are produced from various raw materials combined in specific proportions to achieve the desired chemical composition. This mixture is commonly referred to as a “glass batch.” The glass produced from the batch is generally expressed as a percentage of components, which are stated as oxides. SiO2, Al2O3, CaO, MgO, B2O3, Na2O, K2O, Fe2O3, and small amounts of other oxides are common components of the glass fiber batch. By varying the amounts of these oxides or adding and removing certain oxides, various types of glass fibers can be produced. Examples of glass fiber types include fiber glasses with different compositions such as E-glass, S-glass, R-glass, A- glass, C-glass, and ECR-glass. The glass composition determines properties such as the viscosity of the glass (melting temperature, forming temperature, liquidus temperature), chemical and mechanical durability, density, and the elastic modulus of the glass.

[0006] E-glass is a type of continuous glass fiber used in reinforcement applications. An advantage of E-glass is that its liquidus temperature is approximately 200°F lower than the forming temperature; the forming temperature is typically defined as the temperature at which the viscosity of the glass equals 1 ,000 poise (log 3). E-glass has a wide forming temperature range and a low rate of crystal formation. Historically, commercial E-glass compositions have forming temperatures ranging from 1 ,176 °C to 1 ,287 °C and liquidus temperature values approximately 37 °C to 120 °C lower than the forming temperature.

[0007] The most well-known high-strength compositions for making continuous glass fiber yarns are “S-glass.” S-glass belongs to a family of glasses consisting of oxides of magnesium, aluminum, and silicon, and with this chemical composition, glass fibers with higher mechanical durability compared to E-glasses are produced. S-glass was discovered in the late 1960s and was initially designed for use in high-strength applications such as ballistic armor. R-glass was first developed in the mid-1960s, initially for military applications. R-glass primarily consists of MgO, CaO, Al2O3, and SiO2. Like S-glass, the use of R-glass is limited due to the high melting temperature requirements. Although the high melting temperature during R-glass production has created melting difficulties, newly designed R-glass compositions have overcome melting and forming (fiberizing) obstacles, making them commercially attractive for large-scale production. Again, the melting temperatures, forming temperatures, and liquidus temperatures of high modulus fiber glasses referred to as new R-glass are determined to be higher than standard boron-containing E-glass.

[0008] Producing many glasses with high mechanical durability is costly due to high melting and forming temperatures and other processing constraints. However, production is carried out by bearing high costs for application areas where materials with higher mechanical strength than E-glass are needed (e.g., longer wind turbine blades).

[0009] EP3564196A1 relates to a high modulus glass fiber. The publication discloses a glass fiber composition that has a high elastic modulus and is easily producible, which can facilitate the production of glass fiber. The glass composition contains 50 to 70% SiO2, 15 to 25% Al2O3, 3 to 13% MgO, 3 to 15% CaO, and 0,5 to 5% B2O3.

[0010] SUMMARY OF THE INVENTION

[0011] The object of the invention is to provide a high modulus glass fiber.

[0012] In order to achieve the aforementioned objective, the invention relates to a high modulus glass fiber composition. The glass fiber composition contains, by weight percentage, 50-70% SiO2, 15-25% Al2O3, 5-15% CaO, 5-15% MgO, 0,5-5% B2O3, and 0,5-1 , 5% Na2O. In this way, a glass fiber with high mechanical properties, for example, a Young’s modulus (elastic modulus) value higher than 85 GPa, is obtained.

[0013] In a preferred embodiment of the invention, the SiO2weight percentage is in the range of 51 % to 56%. Thus, as the main oxide, SiO2acts as a network former, increasing the melting temperature and glass durability. SiO2is obtained from kaolin with high silica content and, in some cases, from sand as the main source. In a preferred embodiment of the invention, the CaO weight percentage is in the range of 8% to 11%. Thus, the use of calcium oxide serves as a network modifier in the glass fiber. Additionally, it facilitates melting by reducing viscosity at high temperatures (above the softening temperature). Moreover, the use of CaO increases the chemical durability, tensile strength, and Young’s modulus values of the glass fiber. Since excessive amounts of CaO tend to increase the crystallization tendency of the glass, having very high amounts of CaO, for example, 15% and above, can lead to the formation of crystal particles during the forming of the fiber glass.

[0014] In a preferred embodiment of the invention, the MgO weight percentage is in the range of 11 % to 13%. In this way, the use of magnesium oxide increases the Young’s modulus value of the glass fiber. Like CaO, MgO facilitates melting by reducing viscosity at high temperatures (above the softening temperature) and increases the crystallization tendency of the glass.

[0015] In a preferred embodiment of the invention, the B2O3weight percentage is in the range of 1 % to 4%. In this way, the use of B2O3facilitates melting by providing low viscosity at high temperatures in the glass fiber and reduces total energy consumption. It has been determined through studies that B2O3facilitates melting by lowering the liquidus temperature, which is an advantage for high modulus glass compositions.

[0016] In a preferred embodiment of the invention, the Al2O3weight percentage is in the range of 18% to 20,5%. In this way, it ensures that the threshold Young’s modulus value specified as high modulus is exceeded and also improves the mechanical properties of the high modulus glass fiber.

[0017] In a preferred embodiment of the invention, the K2O weight percentage is in the range of 0,05% to 0,2%. Thus, the use of potassium oxide reduces the viscosity and crystallization tendency of the glass fiber, lowering the melting and forming temperature of the glass. Since the total of Na2O + K2O in E-glass must be below 2% to achieve electrical properties, the K2O value is determined considering the Na2O value, and K2O comes to the glass as an impurity from the raw materials.

[0018] In a preferred embodiment of the invention, the F2weight percentage is in the range of 0,05% to 2%. Thus, fluorine is added to the glass batch as a melting aid and also helps in fiberization. In a preferred embodiment of the invention, the Cr2O3weight percentage is in the range of 0,005% to 0,02%. Cr2O3gives the glass an intense green color, and E-glass with optimum optical properties can be obtained with these amounts of Cr2O3. Cr2O3is not added to the glass batch but comes as an impurity from kaolin.

[0019] In a preferred embodiment of the invention, the SrO weight percentage is in the range of 0,01% to 0,12%. Thus, the use of strontium oxide facilitates the forming of the glass and creates a more stable glass structure. SrO comes to the glass batch as an impurity from colemanite.

[0020] In a preferred embodiment of the invention, the Fe2O3weight percentage is in the range of 0,3% to 0,4%. In this way, it helps the glass to be at an optimum level of reduction, increasing the yield during fiberization. The amount of Fe2O3in the glass is determined according to the amount coming from the raw materials.

[0021] In a preferred embodiment of the invention, the TiO2weight percentage is in the range of 0,25% to 0,4%. In this way, it increases the chemical resistance of the glass and helps to lower the liquidus temperature. The TiO2value in the glass is obtained from impurities in the raw materials In an alternative embodiment, the TiO2value in the glass can be obtained by using rutile.

[0022] In a preferred embodiment of the invention, the SO3weight percentage is in the range of 0,02% to 0,05%. In this way, the fining of the glass is ensured. Since sufficient SO3comes from kaolin and calcined lime to the batch, no additional sulfate source is used.

[0023] In a preferred embodiment of the invention, the ZrO2weight percentage is in the range of 0% to 2,2%. Thus, by adding zircon sand, an increase in the Young’s modulus value of the glass is achieved. Also, the use of ZrO2increases the alkali resistance and acid resistance of the glass fiber.

[0024] In a preferred embodiment of the invention, the BaO weight percentage is in the range of 0,02% to 0,06%. In this way, BaO helps to lower the viscosity of the glass. BaO comes to the glass batch as an impurity from kaolin.

[0025] In a preferred embodiment of the invention, the ZrO2weight percentage is in the range of 0% to 2,2%. In this way, it ensures that the glass fiber has high mechanical properties. DETAILED DESCRIPTION OF THE INVENTION

[0026] In this detailed description, the development subject to the invention is explained with references to examples for better understanding, without any limitation.

[0027] To obtain high modulus glass fiber, the glass fiber composition batch is used. The present composition contains, by weight percentages, 50-58% SiO2; 18-20,5% Al2O3; 10-15% MgO; 5- 15% CaO; 0,5-5% B2O3; and 0,5-1 ,5% Na2O, and other additives.

[0028]

[0029] In the above tables, the percentage weight values of the materials used for the high modulus glass fiber composition are shown.

[0030] In Table 1 , Example 1 contains, by weight percentage, 53,67% SiO2, 20% Al2O3, 8.5% CaO, 12% MgO, 0,8% Na2O, 0,1 % K2O, 4% B2O3, 0,05% F2, 0,01 % Cr2O3, 0,11 % SrO, 0,369% Fe2O3, 0,317% TiO2, 0,04% SO3, and 0,04% BaO. The glass fibers formed from these compositions have a Young’s modulus (fiber form) greater than 85 GPa (12,32 MPSI). In laboratory studies, elastic modulus (Young’s modulus) measurements were made from bulk forms of glass fibers using the Olympus 38 DLP device, and it is known from the literature that the Young’s modulus values of bulk glasses are 5 GPa higher than their fiber form. The density of glass fibers can vary approximately between 2,5 g / cm3and 2,8 g / cm3. In particular, the density of glass fibers can vary approximately between 2,57 g / cm3and 2,68 g / cm3.

[0031] In Example 2 shown in Table 1 , the glass fiber composition contains, by weight percentage, 53,72% SiO2, 20% Al2O3, 10,5% CaO, 12% MgO, 0,8% Na2O, 0,1 % K2O, 2% B2O3, 0,05% F2, 0,01 % Cr2O3, 0,05% SrO, 0,379% Fe2O3, 0,318% TiO2, 0,04% SO3, and 0,04% BaO. In this example, the calcium oxide weight percentage was chosen as the maximum value within the range. Having the weight value of calcium oxide at the maximum value increases the Young’s modulus value of the glass fiber composition above 97 GPa (bulk form), improving its mechanical properties and increasing tensile strength, but like MgO, it also increases the crystallization temperature.

[0032] In Example 3 shown in Table 1 , the glass fiber composition contains, by weight percentage, 55.69% SiO2, 20% Al2O3, 8.5% CaO, 12% MgO, 0,8% Na2O, 0,1 1 % K2O, 2% B2O3, 0,05% F2, 0,01 % Cr2O3, 0,05% SrO, 0,386% Fe2O3, 0,330% TiO2, 0,04% SO3, and 0,04% BaO. In this example, the silicon oxide weight percentage was chosen as the maximum value within the range.

[0033] In Example 4 shown in Table 1 , the glass fiber composition contains, by weight percentage, 54.7% SiO2, 20% Al2O3, 8.5% CaO, 12% MgO, 1 ,8% Na2O, 0,1 1 % K2O, 2% B2O3, 0,05% F2, 0,01 % Cr2O3, 0,05% SrO, 0,379% Fe2O3, 0,325% TiO2, 0,04% SO3, and 0,04% BaO. In this example, the sodium oxide weight percentage was chosen as the maximum value within the range. Surprisingly, while it was expected that the mechanical properties of the glass would be low when the sodium oxide ratio is high, it was determined that it exceeds the threshold Young’s modulus value specified as high modulus in the standards and exhibits high modulus glass properties.

[0034] In Example 5 shown in Table 1 , the glass fiber composition contains, by weight percentage, 53,72% SiO2, 20% Al2O3, 8.5% CaO, 13% MgO, 1 ,8% Na2O, 0,1 % K2O, 2% B2O3, 0,05% F2, 0,01 % Cr2O3, 0,05% SrO, 0,373% Fe2O3, 0,320% TiO2, 0,04% SO3, and 0,04% BaO. In this example, the magnesium oxide weight percentage was chosen as the maximum value within the range. Having the weight value of magnesium oxide at the maximum value increases the bulk Young’s modulus value of the glass fiber composition above 98 GPa, improving the mechanical properties of the glass fiber while increasing the crystallization temperature. While MgO and CaO increase the Young’s modulus values of the glass, they can also increase the liquidus temperature.

[0035] In Example 6 shown in Table 2, the glass fiber composition contains, by weight percentage, 52,6% SiO2, 20% Al2O3, 10,5% CaO, 12% MgO, 0,8% Na2O, 0,1 % K2O, 2% B2O3, 0,047% F2, 0,01 % Cr2O3, 0,05% SrO, 0,370% Fe2O3, 0,313% TiO2, 0,04% SO3, 0,04% BaO, 1 % ZrO2, and 0,13% HfO2. In this example, the aluminum oxide weight percentage was chosen as the maximum value within the range, and zirconium oxide addition was made at a rate of 1 %. Having the weight value of aluminum oxide at the maximum value and adding 1 % zirconium oxide increases the bulk Young’s modulus value of the glass fiber composition above 99,6 GPa, improving the mechanical properties of the glass fiber.

[0036] In Example 7 shown in Table 2, the glass fiber composition contains, by weight percentage, 51 ,5% SiO2, 20% Al2O3, 10,5% CaO, 12% MgO, 0,8% Na2O, 0,1 % K2O, 2% B2O3, 0,047% F2, 0,01 % Cr2O3, 0,05% SrO, 0,361% Fe2O3, 0,307% TiO2, 0,04% SO3, 0,030% BaO, 2% ZrO2, and 0,26% HfO2. With the increase of the ZrO2value, an increase up to 100 GPa in the bulk Young’s modulus value of the glass was achieved. The strong effect of ZrO2on Young’s modulus was determined.

[0037] In Example 8 shown in Table 2, the glass fiber composition contains, by weight percentage, 53,46% SiO2, 18% Al2O3, 10,5% CaO, 12% MgO, 0,8% Na2O, 0,1 % K2O, 2% B2O3, 0,047% F2, 0,01 % Cr2O3, 0,05% SrO, 0,373% Fe2O3, 0,319% TiO2, 0,04% SO3, 0,04% BaO, 2% ZrO2, and 0,26% HfO2.

[0038] In Example 9 shown in Table 2, the glass fiber composition contains, by weight percentage, 54.58% SiO2, 20% Al2O3, 8.5% CaO, 12% MgO, 0,8% Na2O, 0,1 % K2O, 2% B2O3, 0,047% F2, 0,01 % Cr2O3, 0,05% SrO, 0,377% Fe2O3, 0,325% TiO2, 0,04% SO3, 0,04% BaO, 1 % ZrO2, and 0,13% HfO2.

[0039] In Example 10 shown in Table 2, the glass fiber composition contains, by weight percentage, 53,47% SiO2, 20% Al2O3, 8.5% CaO, 12% MgO, 0,8% Na2O, 0,1 % K2O, 2% B2O3, 0,047% F2, 0,01 % Cr2O3, 0,05% SrO, 0,368% Fe2O3, 0,319% TiO2, 0,04% SO3, 0,04% BaO, 2% ZrO2, and 0,26% HfO2.

[0040] The production of the high modulus glass fiber subject to the invention is carried out by passing the molten glass material through a bushing. When the glass exits from the very fine (micron- thickness) holes in the bushing, it is cooled by methods such as water jets and mechanically drawn to a high-speed winding spool. As the fiber winds, the molten glass streams are drawn into thin fibrous elements called filaments through tension.

[0041] In some example applications, the glass fiber production includes a suitable melting furnace, such as a tank furnace (not shown), which can be used to form molten glass from batch compositions. The molten glass is discharged from the furnace and first directed into channels to lower the temperature of the glass for forming. Following the channels, there are bushings under each channel, and the glass comes to these bushings, filling them. From the thousands of micron-thick tips in the bushings, glass is drawn at micron thickness and fiberized. The fiberized glass touches the applicator, integrating with the binder on the applicator, forming the glass fiber composite material, and products are made by winding or chopping.

Claims

CLAIMS1. A high modulus glass fiber composition characterized by comprising, by weight percentage:50-70% SiO215-25% Al2O35-15% Ca5-15% MgO0,5-5% B2O30,5-1 , 5% Na2O.

2. A glass fiber composition according to claim 1 , wherein the SiO2weight percentage is in the range of 51 % to 56%.

3. A glass fiber composition according to any of the preceding claims, wherein the CaO weight percentage is in the range of 8% to 11 %.

4. A glass fiber composition according to any of the preceding claims, wherein the MgO weight percentage is in the range of 11 % to 13%.

5. A glass fiber composition according to any of the preceding claims, wherein the B2O3weight percentage is in the range of 1% to 4%.

6. A glass fiber composition according to any of the preceding claims, wherein the Al2O3weight percentage is in the range of 18% to 20,5%.

7. A glass fiber composition according to any of the preceding claims, wherein the K2O weight percentage is in the range of 0,05% to 0,2%.

8. A glass fiber composition according to any of the preceding claims, wherein the F2weight percentage is in the range of 0,05% to 2%.

9. A glass fiber composition according to any of the preceding claims, wherein the Cr2O3weight percentage is in the range of 0,005% to 0,02%.

10. A glass fiber composition according to any of the preceding claims, wherein the SrO weight percentage is in the range of 0,01% to 0,12%.

11. A glass fiber composition according to any of the preceding claims, wherein the Fe2O3weight percentage is in the range of 0,3% to 0,4%.

12. A glass fiber composition according to any of the preceding claims, wherein the TiO2weight percentage is in the range of 0,25% to 4%.

13. A glass fiber composition according to any of the preceding claims, wherein the SO3weight percentage is in the range of 0,02% to 0,05%.

14. A glass fiber composition according to any of the preceding claims, wherein the BaO weight percentage is in the range of 0,02% to 0,06%.

15. A glass fiber composition according to any of the preceding claims, wherein the ZrO2weight percentage is in the range of 0% to 2,2%.

Images