KR20040080828A - A Glass Filament Constitution for high Strength and Elastic Modulus - Google Patents

Abstract

PURPOSE: Provided is a glass fiber composition of the SiO2-Al2O3-MgO-ZnO system for use as reinforcing materials requiring high strength and high elasticity. CONSTITUTION: The glass fiber composition for high strength reinforcing materials comprises 55-70wt.% of SiO2, 15-30wt.% of Al2O3, 5-15wt.% of MgO and 2-10wt.% of ZnO, wherein the total amount of MnO and ZnO is 7-16wt.%. The glass fibers are produced by the following steps of: mixing SiO2 as network formers, MgO and ZnO as network modifiers and Al2O3 as intermediates in the proportions corresponding to the above composition, wherein ZnO lowers melting point and viscosity to produce homogeneous and clear marbles; melting mixtures to produce clear glass marbles(20mm diameter) in a smelter; melting glass marbles in a Pt bushing; and fast drawing glass fibers(filaments) from molten glass.

Description

A glass filament constitution for high strength and elastic modulus

The present invention relates to a glass long fiber composition having a high strength and high modulus of elasticity, and more particularly, an appropriate ratio of SiO ₂ , a mesh forming oxide, MgO and ZnO, a modified oxide, and Al ₂ O ₃ , an intermediate oxide, used as main components. Clear glass marble is produced in a smelter and glass filaments having high strength and high elastic modulus are obtained by high-speed withdrawal using a marble bushing, especially in the addition of ZnO. By the melting point and the viscosity decrease due to the more homogeneous and the manufacture of the marble excellent in the clarity state is possible and relates to a long fiber composition having a uniform fiber diameter.

Generally, glass fiber is classified into glass fiber, filament and short fiber according to its shape, and long fiber is in the form of yarn wound by pulling out molten glass at high speed, and short fiber is molten glass. It is manufactured in fibrous form by centrifugal force method or flame method. It is characterized by low thermal conductivity and elongated shape. It is used in various applications such as heat insulation, cold insulation, heat insulation, sound insulation, sound absorption, and filter. It is classified into rock wool and ceramic fiber.

According to the composition, E, S, Cemfil, AR-glass, etc. are manufactured according to the composition. The E-glass is called alkali-free glass, has an alkali content of 0.8% or less, and has excellent electrical properties and weathering resistance. It is mainly used for reinforcement materials such as building equipment and electrical insulation. While S-glass has excellent mechanical properties and high manufacturing cost, it is used only in special areas such as aircraft, engines, and munitions. Kempil-glass and AR-glass are used for cement reinforcement due to their excellent resistance to alkali.

There are two methods for preparing long fibers, a direct melting method and a marble melting method. The direct melting method is applied in a large-scale factory. The precise mixing of the homogeneous raw material is mainly carried out in the tank furnace, and the molten glass is clarified to spin the molten glass through the nozzle in the bushing attached to the furnace at an appropriate working temperature. As a method, manufacturing costs are inexpensive, but varietal conversion and shutdown are difficult. Marble melting is primarily a method of melting raw materials to produce a marble of a certain diameter and then remelting and spinning them, which is suitable for small quantity production of a large variety of products and is easy to resume operation. It has an expensive disadvantage.

The long fiber composition, which has high strength and high modulus of elasticity and is used as a composite reinforcement material, can be found in various literatures. The approximate composition is 65% by weight of SiO ₂ , 25% by weight of Al ₂ O ₃ , and MgO 10. By weight and as impurities, less than 1% by weight of R ₂ O, TiO ₂ , Fe ₂ O _3, etc., are introduced from the starting materials or added as a melt aid. However, the composition has a high melting temperature, which is difficult to obtain a glass in a clarified and homogeneous state suitable for producing glass fibers by primary melting in a smelter, as well as a very high Log 2.5 viscosity temperature of 1500 ° C. or higher. The temperature variation in the bushing becomes large, which makes it difficult to manufacture a glass fiber with a uniform diameter, and the life of the bushing is considerably shortened.

Therefore, research into glass fiber for reinforcement of a composition which may have a low melting temperature and a fiberization temperature is progressing.

The glass fibers disclosed in U.S. Patent No. 5,569,629 are characterized by long fibers at a high temperature of 1260 ° C. in a SiO ₂ -Al ₂ O ₃ -MgO-TiO ₂ -ZrO ₂ based composition, and are manufactured by a direct melting method, Although it has long strength, high modulus and small coefficient of thermal expansion, it has relatively large fiber diameter and very low tensile strength compared to S-glass.

The glass fibers disclosed in U.S. Patent No. 4,582,748 have a SiO ₂ -Al ₂ O ₃ -B ₂ O ₃ -MgO-based composition, which has a small coefficient of thermal expansion, a high modulus of elasticity and a low dielectric constant, and is a suitable fiber composition for reinforcement of electric plywood. Its use is limited to various applications requiring high strength.

Therefore, glass fiber for reinforcement having high strength and high modulus of elasticity can be melted at lower temperature, so that it is excellent in clarity even in melting in the melting furnace (Smelter) which is a melting type electric furnace by electric current, thereby producing a homogeneous marble. It is possible to re-melt it, and the situation is required to develop a long fiber that is wound by a high speed withdrawal through the nozzle of the bushing.

Accordingly, the inventors of the present invention have made an effort to solve the above problems, and as a result, an appropriate ratio of SiO ₂ , which is a mesh forming oxide, MgO and ZnO, which are modified oxides, and Al ₂ O ₃ , which are intermediate oxides, are used as main components of glass fibers. By making the marble with low melting temperature and good clarity even in the primary melting in the furnace, remelting it in the marble bushing and drawing it out at high speed through the nozzle to produce glass fibers having high strength and high elastic modulus. The invention was completed.

Accordingly, an object of the present invention is to provide a glass long fiber composition having good high strength and high modulus.

1 is a graph showing the difference between the fiberization temperature and the recrystallization temperature according to the content of MgO + ZnO.

2 is a graph showing the change in tensile strength of the glass fiber to the content of Al ₂ O ₃ .

The present invention is characterized by a glass fiber composition for a high-strength reinforcing material comprising 55 to 70% by weight of SiO ₂ , 15 to 30% by weight of Al ₂ O ₃ , 5 to 15% by weight of MgO and 2 to 10% by weight of ZnO.

Referring to the present invention in more detail as follows.

The present invention is a four-component composition of SiO ₂ -Al ₂ O ₃ -MgO-ZnO in the glass fiber used for high-strength reinforcing material is low melting temperature and excellent in clarity state can be produced homogeneous glass and remelted The long fiber to be produced relates to a glass long fiber composition for reinforcement of a composite material which is excellent in mechanical properties of high strength and high modulus of elasticity and thus requires high strength physical properties.

Referring to the glass long fiber composition having a high strength and high modulus according to the present invention in more detail according to the components as follows.

First, it is preferable to contain 55 to 70% by weight of SiO _{2, which} is the main component of the glass fiber, but if the content is more than 70% by weight, the composition is difficult to melt and the viscosity at high temperature is large, resulting in a clarified state. There is a problem in the production of continuous strands at the time of fiberization because the bubble remaining in the glass is very bad. On the other hand, if the content is less than 55% by weight, the raw material cost increases due to Al ₂ O ₃ , MgO and ZnO, which must be relatively increased, and the mechanical properties of the fiber are decreased and the recrystallization temperature is increased due to the increase of the modified oxide. there is a problem.

The glass fiber composition for high strength reinforcement according to the present invention contains MgO and ZnO, which are modified oxides, and MgO is preferably contained in the total fiber composition 5 to 15% by weight, if the content is less than 5% by weight of the glass viscosity There is a problem that increases the problem occurs in the re-melt by the bushing of the platinum material, if more than 15% by weight there is a problem that the recrystallization temperature rises as well as the mechanical properties decrease. In addition, ZnO, another modified oxide added to glass fibers, preferably contains 2 to 10% by weight in the total fiber composition, and Zn having a large atomic radius makes the glass structure more robust while lowering the melting temperature. do. However, if the content is less than 2% by weight, there is a problem in that the melting point cannot be expected to be lowered. If the content is more than 10% by weight, there is a problem that the raw material costs are increased as well as the mechanical properties are decreased due to the content of the modified oxide.

Particularly, the sum of the contents of the modified oxides MgO and ZnO is preferably used in an amount of 7 to 16% by weight. When the sum is less than 7% by weight, the melting temperature is rapidly increased. This is because the difference between the temperature and the crystallization temperature is reduced, which increases the possibility of generating crystals in the bushing during the fiberization operation, thereby making it difficult to produce stable fibers.

Al ₂ O _{3 as an} intermediate oxide is preferably contained in an amount of 15 to 30% by weight in the total glass fiber composition, but if the content is less than 15% by weight, there is a problem that the durability of the glass fiber becomes poor and the expression of mechanical properties becomes difficult. If more than 30% by weight, the melting temperature rises.

In addition, the glass fiber composition for high-strength reinforcement according to the present invention may contain impurities such as Na ₂ O, K ₂ O, TiO ₂ , Fe ₂ O ₃ in an amount of 2 wt% or less based on the total fiber composition. The impurity may be added in a small amount as a fiberizing aid of the fiber composition, or may be a by-product produced by reacting each component of the composition. When the amount is included in an excessive amount, the reaction of the fiber composition may be inhibited. Physical properties may be reduced.

The glass fiber according to the present invention prepared from the fiber composition containing the above components and contents can produce a homogeneous marble with a relatively low melting temperature and excellent clarity, and can produce continuous strands by remelting the marble. The average particle diameter of the fiber thus produced is uniform in the range of 9 to 25 μm, depending on the application, and is used in engineering plastics, engines, and munitions requiring high strength due to excellent mechanical properties of high strength and high elastic modulus. This is possible.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Examples 1-9 and Comparative Examples 1-11

Next, the composition having the ingredients and contents shown in Table 1 was melted in a smelter to prepare a glass marble (average diameter of 20 mm and an error range of ± 1 mm), and remelt it in a platinum bushing (200 hole). A glass fiber having an average fiber diameter of 10 μm was prepared by a high speed drawing (collet diameter is 300 mm and a winding speed of 2,000 to 2,500 rpm) using a winder. For comparison, glass fibers of E-glass composition and S-glass composition (Comparative Examples 8 to 10) were prepared, and physical properties were also compared with S-glass products (Comparative Example 11).

division SiO ₂ Al ₂ O ₃ MgO CaO ZnO B ₂ O ₃ impurities Remarks Example 1 58.5 29.2 6.1 5.6 0.6 Example 2 63.4 23.0 9.7 3.3 0.6 Example 3 65.5 18.0 10.1 5.9 0.5 Example 4 67.2 16.7 5.4 9.8 0.9 Example 5 68.7 15.5 7.0 8.3 0.5 Example 6 69.4 15.4 12.6 2.1 0.5 Example 7 55.2 28.5 11.2 4.3 0.8 Example 8 56.8 27.1 6.0 9.4 0.7 Example 9 61.8 22.5 8.9 6.1 0.7 Comparative Example 1 52.9 21.0 13.6 11.8 0.7 Comparative Example 2 57.3 20.4 9.3 12.4 0.6 Comparative Example 3 59.2 15.1 16.6 8.3 0.8 Comparative Example 4 62.9 31.2 3.1 2.2 0.6 Comparative Example 5 66.6 25.1 2.4 5.2 0.7 Comparative Example 6 68.1 14.1 10.3 6.7 0.8 Comparative Example 7 72.4 13.3 8.7 4.8 0.8 Comparative Example 8 53.7 13.6 4.4 17.5 10.0 0.8 E-glass Comparative Example 9 55.2 14.8 3.3 18.7 7.3 0.7 E-glass Comparative Example 10 64.5 25.0 10.0 0.5 S-glass Comparative Example 11 66.7 23.3 9.4 0.6 S-glass products

Test Example 1: Glass Marble

The size distribution, the fiberization temperature and the recrystallization temperature of the bubbles present in the glass marble to be prepared are shown in Table 2 below, and the measuring method is as follows.

1. Measurement of bubble size distribution in marble: Measure the size and number of bubbles in the marble using an optical microscope, and then measure the average size, standard deviation, and the number of bubbles per unit volume. glass marble) was confirmed. Bubbles in the glass marble form a huge bubble by incorporation between fine bubbles and then float out of the glass marble to degas. Therefore, the more fine bubbles, the less the molten state proceeds, it is difficult to predict the glass marble manufacturing.

2. Measurement of fiberization temperature: Viscosity change with temperature was observed using a high temperature viscometer, and Log 2.5 viscosity temperature, which is suitable for fiber extraction, was compared.

3. Recrystallization temperature measurement: Marbles were ground to an appropriate size and sampled at 30 mg, and then the crystallization temperature was measured and compared by heating the temperature to 1500 ° C. at a rate of 10 ° C./min using a DTA thermal analyzer.

The purpose of measuring the fiberization temperature and the recrystallization temperature is that the smaller the difference (ΔT) between the two temperatures, the greater the probability of recrystallization inside the bushing, especially at the nozzle tip, during the fiber production, which makes it difficult to produce a stable fiber. The difference between temperature and recrystallization temperature is measured to predict the possibility of fibrosis.

division bubble Fiberization Temperature (℃) Recrystallization Temperature (℃) △ T Size (μm) Standard Deviation Count (ea / cc) Example 1 30.6 8.9 9 1469 1358 111 Example 2 33.6 10.2 11 1480 1363 117 Example 3 29.9 7.3 10 1456 1373 83 Example 4 33.0 10.6 9 1472 1359 113 Example 5 37.5 10.7 11 1447 1348 99 Example 6 36.4 11.5 14 1462 1353 109 Example 7 34.1 9.1 14 1466 1378 88 Example 8 31.8 8.5 12 1443 1362 81 Example 9 32.4 9.3 11 1477 1371 106 Comparative Example 1 32.7 9.3 6 1449 1394 55 Comparative Example 2 29.3 8.2 6 1451 1390 61 Comparative Example 3 30.9 8.1 5 1438 1385 53 Comparative Example 4 13.1 3.8 64 - - - Comparative Example 5 11.6 4.2 98 - - - Comparative Example 6 32.6 8.3 13 1448 1384 64 Comparative Example 7 13.7 4.7 152 - - - Comparative Example 8 32.7 9.3 6 1219 1073 146 Comparative Example 9 34.1 9.1 14 1239 1082 157 Comparative Example 10 13.8 5.8 125 - - - Comparative Example 11 OCF S2-Glass Fiber (Because it is a commercial fiber product, bubbles cannot be observed in the marble) 1545 1470 75

As shown in Table 1, the content of the composition for preparing the glass fiber was changed in the composition ratio in the form of combining other compositions while increasing the SiO ₂ content.

The size and number of the bubbles of the marble prepared by the development composition of the present invention are almost the same in general except for a few compositions when compared to Comparative Examples 8 and 9 which are relatively low melting point E-glass composition. On the other hand, Comparative Example 10, which is a S-glass composition prepared under the same conditions, was found to be difficult to manufacture marble when melting in the furnace because a large amount of small bubbles.

Comparative Examples 4, 5, and 7 each have a high Al ₂ O ₃ content, a low MgO and ZnO content, or a high SiO ₂ content, all of which have a high melting point and a high viscosity even when a liquid phase is formed. The tendency was not to merge between the fine bubbles.

The rate of rise of bubbles present in the glass liquid phase can be calculated by the following equation (1) by Stokes' law.

In Equation 1, V is the floating speed (cm / sec) of the bubble, r is the radius of the bubble (cm), g is the acceleration of gravity (cm / sec ² ), d and d 'is the gas of the molten glass and gas in the bubble Density (g / cm <^3> ) and (eta) mean the viscosity (poise, g / cm * ec) of a molten glass.

Under conditions of high viscosity, bubbles rise slowly and their mobility is low, and growth by bubble aggregation cannot be expected. Therefore, as can be seen in Comparative Examples 4, 5 and 7, the size of the bubbles was small and the number was considerably large, but it was found that the composition was not able to produce a clear glass marble by melting in a furnace. .

The composition prepared according to the present invention has a smaller difference between the fiberization temperature and the recrystallization temperature compared with 146 ° C of Comparative Example 8, which is an E-glass composition, and 157 ° C of Comparative Example 9, but at 75 ° C of Comparative Example 11, which is an S-glass product. In comparison, the difference was large, and thus, the manufacturing conditions were improved by reducing the risk of recrystallization which may occur in the marble bushing when manufacturing the glass fiber.

As shown in Table 2, Comparative Examples 1, 2, 3 and 6 were found to decrease the difference between the fiberization temperature and the recrystallization temperature as the content of MgO and ZnO increases. In particular, the MgO content is preferably 15% by weight or less from Comparative Example 3 in which the MgO content is 16.6% by weight, and the ZnO content in Comparative Example 1 is 11.8% by weight. It was found that 10 wt% or less is preferable. In addition, it can be seen from Figure 1 that when the content of MgO + ZnO exceeds 16% by weight, ΔT rapidly decreases.

Test Example 2 Measurement of Physical Properties

A fiberization test was carried out by melting and fast drawing in a marble bushing for a composition capable of producing a clear glass marble having a bubble size and number similar to those of Comparative Examples 8 and 9, which are E-glass compositions. The tensile strength of the glass fiber (single virgin filament) having a diameter of 10 μm measured using a tester (UTM) and the elastic modulus calculated by the following Equation 2 are summarized in Table 3 below.

division Tensile Strength (Mpa) Modulus of elasticity (Gpa) Example 1 4796 85.6 Example 2 4733 93.7 Example 3 4638 90.8 Example 4 4610 88.6 Example 5 4577 90.1 Example 6 4587 89.9 Example 7 4688 89.7 Example 8 4561 88.7 Example 9 4709 91.1 Comparative Example 1 3755 82.3 Comparative Example 2 3856 80.7 Comparative Example 3 3937 84.4 Comparative Example 4 - - Comparative Example 5 - - Comparative Example 6 4254 74.8 Comparative Example 7 - - Comparative Example 8 2591 58.6 Comparative Example 9 2638 62.3 Comparative Example 10 - - Comparative Example 11 - 93.7

Tensile strength and elastic modulus of Comparative Example 11, which is an S-glass product, and the glass fiber prepared by the composition of the present invention had almost the same or higher values. On the other hand, in Comparative Examples 1, 2, 3, and 6, it was estimated that the content of the modified oxide is large, thereby showing a relatively low physical property value.

As shown in Figure 2, as the content of Al ₂ O _{3 It} can be seen that the tensile strength tends to increase, Comparative Examples 1, 2 and 3 showing a value of less than 4000 Mpa is the formula mentioned above It was a composition containing much oxide. Therefore, in order to have a value equal to or higher than the physical properties of the S-glass product, the content of Al ₂ O ₃ is preferably set to 15% by weight or more.

As described above, the glass fiber produced by the composition of the present invention is to produce a clear glass marble (clear glass marble) excellent in the clarity and homogeneity even in the melting in the furnace showing the melting behavior by the electric conduction method. The difference between the fiberization temperature and the recrystallization temperature (ΔT) is large and stable to remelting at the time of fiberization, and the glass fiber re-melted in the bushing and fiberized by high-speed withdrawal from the nozzle is equivalent to S-glass. It has tensile strength and modulus of elasticity and can be applied to military or industrial fields requiring high strength and high modulus.

Claims (2)

A glass fiber composition having a high strength and high modulus of elasticity, comprising 55 to 70 wt% of SiO ₂ , 15 to 30 wt% of Al ₂ O ₃ , 5 to 15 wt% of MgO, and 2 to 10 wt% of ZnO. The glass fiber composition having a high strength and high modulus of elasticity according to claim 1, wherein the sum of the contents of MgO and ZnO is 7 to 16% by weight.