High modulus glass fiber composition

Abstract

The invention relates to a high modulus glass fiber composition. The glass fiber composition contains, by weight percentage, 50-58% SiO2, 18-20,5% Al2O3, 5-15% CaO, 10-15% MgO, 0,5- 5% B2O3, preferably 0-2,2% ZrO2.

Description

[0001] DESCRIPTION

[0002] HIGH MODULUS GLASS FIBER COMPOSITION

[0003] TECHNICAL FIELD

[0004] The present invention relates to a high modulus glass fiber composition.

[0005] BACKGROUND ART

[0006] Glass fiber manufactured for use in composite applications is produced from various raw materials combined in specific proportions to achieve the desired chemical composition. This proportion is generally referred to as the “glass batch.” The glass produced from the glass batch is typically expressed as a percentage of components, represented as oxides. Common components of the glass fiber batch include SiO2, Al2O3, CaO, MgO, B2O3, Na2O, K2O, Fe2O3, and small amounts of other oxides. By varying the amounts of these oxides or by 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.

[0007] 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 generally defined as the temperature at which the viscosity of the glass equals 1000 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 between 1176 °C and 1287 °C, with liquidus temperature values approximately 37 °C to 120 °C lower than the forming temperature.

[0008] 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 glass fibers with higher mechanical durability compared to E-glasses are produced with this chemical composition. 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 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 caused melting difficulties, newly designed R-glass compositions have overcome the melting and forming (fiberizing) barriers, making them commercially attractive for large-scale production. The melting temperatures, forming temperatures, and liquidus temperatures of high modulus fiber glasses referred to as new R-glass are determined to be higher compared to standard boron-containing E-glass.

[0009] Producing many glasses with high mechanical durability is costly due to high melting and forming temperatures and other process constraints. However, production is carried out at high costs for application areas where materials with higher mechanical strength than E-glass are needed (e.g., longerwind turbine blades).

[0010] Publication EP3564196A1 relates to a high modulus glass fiber. This publication provides a glass fiber composition that has a high elastic modulus and is easy to produce, 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.

[0011] SUMMARY OF THE INVENTION

[0012] The object of the invention is to provide a high modulus glass fiber.

[0013] To achieve the aforementioned object, the invention relates to a high modulus glass fiber composition. The glass fiber composition contains, by weight percentage, 50-58% SiO2, 18- 20,5% Al2O3, 5-15% CaO, 10-15% MgO, 0,5-5% B2O3, Preferably 0-2,2% ZrO2. 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.

[0014] 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 containing high silica and, in some cases, from sand as the main source. In a preferred embodiment, the CaO weight percentage is in the range of 8% to 11%. With the use of calcium oxide, it acts as a network modifier in the glass fiber. Additionally, it facilitates melting by reducing the viscosity at high temperatures (above the softening temperature). Furthermore, the use of CaO increases the chemical durability, tensile strength, and Young’s modulus values of the glass fiber. Since excessive use of CaO tends to increase the crystallization tendency of the glass, having very high amounts — example: 15% and above — may cause the formation of crystal particles during the shaping of fiber glass.

[0015] In a preferred embodiment, the MgO weight percentage is in the range of 11 % to 13%. The use of magnesium oxide increases the Young’s modulus value of the glass fiber. Like CaO, MgO facilitates melting by reducing the viscosity at high temperatures (above the softening temperature) and increases the crystallization tendency of the glass.

[0016] In a preferred embodiment, the B2O3weight percentage is in the range of 1% to 4%. The use of B2O3ensures that the glass fiber has low viscosity at high temperatures, facilitating melting and reducing total energy consumption. Studies have determined that B2O3facilitates melting by lowering the liquidus temperature, which is an advantage for high modulus glass compositions.

[0017] In a preferred embodiment, the Na2O weight percentage is in the range of 0,5% to 1 ,5%. This ensures the electrical properties (electrical insulation) of E-glass by using less than 2% sodium oxide.

[0018] In a preferred embodiment, the K2O weight percentage is in the range of 0,05% to 0,2%. 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 less than 2% to ensure electrical properties, the K2O value has been determined considering the Na2O value, and K2O comes to the glass as an impurity from the raw materials.

[0019] In a preferred embodiment, the F2weight percentage is in the range of 0,05% to 2%. Fluorine is added to the glass batch both as a melting aid and to assist in fiberization.

[0020] In a preferred embodiment, the Cr2O3weight percentage is in the range of 0,005% to 0,02%. Cr2O3gives the glass an intense green color, and with glass containing Cr2O3in these amounts, E-glass with optimum optical properties can be obtained. Cr2O3is not added to the glass batch but comes as an impurity from kaolin. In a preferred embodiment, the SrO weight percentage is in the range of 0,01% to 0,12%. The use of strontium oxide facilitates the shaping of the glass and creates a more stable glass structure. SrO comes to the glass batch as an impurity from cullet.

[0021] In a preferred embodiment, the Fe2O3weight percentage is in the range of 0,3% to 0,4%. It helps the glass to be at the 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.

[0022] In a preferred embodiment, the TiO2weight percentage is in the range of 0,25% to 0,4%. It increases the chemical resistance of the glass and helps to lower the liquidus temperature. The TiO2value in the glass is obtained from the impurity coming from the raw materials. In an alternative embodiment, the TiO2value in the glass can be obtained by the use of rutile.

[0023] In a preferred embodiment, the SO3weight percentage is in the range of 0,02% to 0,05%. The fining of the glass is ensured. Since sufficient SO3comes from kaolin and calcined lime in the batch, no additional sulfate source is used.

[0024] In a preferred embodiment, the ZrO2weight percentage is in the range of 0% to 2,2%. With the addition of zircon sand, an increase in the Young’s modulus value of the glass is achieved. Additionally, the use of ZrO2increases the alkali resistance and acid resistance of the glass fiber

[0025] In a preferred embodiment, the BaO weight percentage is in the range of 0,02% to 0,06%. BaO helps to reduce the viscosity of the glass. BaO comes to the glass batch as an impurity from kaolin.

[0026] DETAILED DESCRIPTION OF THE INVENTION

[0027] In this detailed description, the development subject to the invention is explained with references to examples solely to better illustrate the subject and without any limitation.

[0028] To obtain high modulus glass fiber, a glass fiber composition batch is used. The present composition contains, in weight percentages: 50% - 58% SiO2, 18% - 20% Al2O3,10% - 15% MgO, 5% - 15% CaO, 1 % - 4% B2O3, 0,5% - 1 ,5% Na2O and other additives.

[0029] The tables above show the percentage weight values of the materials used for the high modulus glass fiber composition. In Example 1 of Table 1 , the composition by weight contains %53,67 SiO2, %20 A12O3, %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 Young’s modulus in fiber form is greater than 85 GPa (12.32 MPSI). Laboratory studies using the Olympus 38 DLP device measured the elastic modulus (Young’s modulus) of the bulk forms, and it’s known that bulk glasses have Young’s modulus values approximately 5 GPa higher than the fiber form. The density of glass fibers varies between approximately 2,5 g / cm3and 2,8 g / cm3, specifically between 2,57 g / cm3and 2,68 g / cm3.

[0030] In Example 2 of Table 1 , the glass fiber composition contains 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. The calcium oxide weight percentage is selected at the maximum within the range. This increases the bulk Young’s modulus value above 97 GPa, improving mechanical properties and tensile strength but also increasing the crystallization temperature.

[0031] In Example 3 of Table 1 , the glass fiber composition contains %55,69 SiO2, %20 AI2O3, %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, %0,33 TiO2, %0,04 SO3, %0,04 BaO. In this example, silicon dioxide selected at the maximum weight percentage within the range.

[0032] In Example 4 shown in Table 1 , the glass fiber composition contains, by percentage weight, 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 weight percentage of sodium oxide has been selected as the maximum value within its weight percentage range. In Example 5 shown in Table 1 , the glass fiber composition contains, by percentage weight, 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, 0,32% TiO2, 0,04% SO3, and 0,04% BaO. In this example, the weight percentage of magnesium oxide has been selected as the maximum value within its weight percentage range. Having the weight value of magnesium oxide at the maximum 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 contribute to increasing the Young’s modulus values of the glass, they can also raise the liquidus temperature.

[0033] In Example 6 shown in Table 2, the glass fiber composition contains, by percentage weight, 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, 0,37% Fe2O3, 0,313% TiO2, 0,04% SO3, 0,04% BaO, 1 % ZrO2, and 0,13% HfO2. In this example, the weight percentage of aluminum oxide has been selected as the maximum value within its weight percentage range, and zirconium oxide has been added at a rate of 1 %. Having the weight value of aluminum oxide at the maximum and the addition of 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.

[0034] In Example 7 shown in Table 2, the glass fiber composition contains, by percentage weight, 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, 0,03% BaO, 2% ZrO2, and 0,26% HfO2. With the increase in the ZrO2value, an increase in the bulk Young’s modulus of the glass up to 100 GPa has been achieved. The strong effect of ZrO2on the Young’s modulus has been determined.

[0035] In Example 8 shown in Table 2, the glass fiber composition contains, by percentage weight, 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.

[0036] In Example 9 shown in Table 2, the glass fiber composition contains, by percentage weight, 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.

[0037] In Example 10 shown in Table 2, the glass fiber composition contains, by percentage weight, 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.

[0038] The production of the high modulus glass fiber is carried out by passing the molten glass material through a bushing. When the glass exits through the very fine (micron-thickness) holes in the bushing, it is cooled by methods such as water jets and mechanically drawn onto a highspeed winding spool. As the fiber winds, tension draws the molten glass streams into thin fibrous elements called filaments.

[0039] In practical applications, glass fiber production utilizes a suitable melting furnace, such as a tank furnace, to create molten glass from batch compositions. The molten glass is discharged from the furnace and first directed into channels to lower its temperature for forming. Below each channel are bushings, which the glass fills. Glass is drawn from the bushings through thousands of micron-thick tips, fiberizing it. The fiberized glass contacts an applicator, integrating with the binder on it to form a glass fiber composite material. Products are made by winding or chopping processes.

Claims

CLAIMS1. A high modulus glass fiber composition characterized by comprising, by weight percentage:50-58% SiO218-20,5% Al2O35-15% CaO 10-15% MgO 0,5-5% B2O3preferably 0-2,2% ZrO2.

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

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

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

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

6. The glass fiber composition according to any of the preceding claims, wherein the Na2O weight percentage is in the range of 0,5% to 1 ,5%.

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

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

13. The 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. The 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%.

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