MXPA98009902A - Biosoluble pot and marble (flame attenuated)-derived fiberglass - Google Patents

Abstract

Glass compositions suitable for pot and marble fiberization display excellent chemical resistance to both acids and moisture while being highly biosoluble at the same time. The glass compositions are characterized by ratios of components which are reflective of acid resistance, biosolubility, and moisture resistance. Preferred glasses have a difference between HTV (103 poise) and liquidus greater than 500°F, and a biodissolution greater than about 350 ng/cm2/hr.

Description

BIOSOLUBLE GLASS FIBERS. PREPARED BY THE METHOD OF "PEROL AND MARBLE" TECHNICAL FIELD The present invention pertains to glass fiber products, prepared from glass compositions, suitable for fibrillation, by the "perol and marble" method. These fibers exhibit increased biosolubility, while maintaining the other desired properties.

Description of the Related Art Glass fibers have many thousands of uses, including the reinforcement of polymer matrix composites, the preparation of hot formable intermediates, for use as roof linings and hoods in vehicles; air and water filtration means; and sound and heat insulation products. The preparation and / or subsequent processing of such materials often involves stages of handling, which result in staple or broken fibers, which can be inhaled. As it is impractical or impossible to remove these fibers from the body, it has become important to create glass compositions that exhibit high degrees of biosolubility, that is, they are rapidly solubilized in biological fluids. When high biosolubility is the only factor that needs to be considered, a solution to the biosolubility problem would be achieved quickly. However, in addition to being biosoluble, glass fibers must also possess a number of other physical and chemical characteristics. For example, in many applications, such as in battery separators, high resistance to chemicals (eg acids) is required. As can easily be imagined, high chemical resistance and high biosolubility are highly conflicting characteristics. Glass fibers must also be strong and resistant to moisture. If moisture weakens glass fibers appreciably, their application capacity for many uses deteriorates. Weakened glass fibers not only have a lower strength and modulus of tension than desired, but also break and fracture more easily, thus increasing the risk of inhalation, etc. For the same consideration, moisture-resistant glass fibers, which have low strength, to begin with, do not meet many requirements in the first place either. For example, construction insulation products are transported in compressed form. If the glass fibers of the insulation product are weak or brittle, many fibers will break during compression, increasing not only the number of small fibers that are bioavailable, but also producing an inferior product, which can not recover a sufficient quantity of fibers. its pre-compressed thickness. Strong fibers that are not resistant to moisture also exhibit a large amount of rupture, especially under wet storage, as will be illustrated below. Finally, the glass fibers must be prepared from glass compositions that can be processed economically. The two main methods of producing glass wool fibers are the perol and marble method and the centrifugal or "rotary" method. In the latter, the molten glass enters a centrifugal spinner from the crucible of a glass melting furnace. As the centrifugal spinner rotates, a stream of glass beads of relatively large diameter is produced from the holes located in the periphery of the spinneret. These large diameter cords come into immediate contact with a jet of intense hot gas, produced by the ovens located around the spinner. The hot gas attenuates the large diameter cords in fine elongated fibers, which can be collected in a moving band. Since glass is an amorphous rather than crystalline "solid", crystallization in the molten state or during fibrillation will interrupt the formation process of the glass fibers, with disastrous results. In the rotary process, the ingredients of the glass are first melted in the glass melter before its entry into the furnace hearth-, the home feed is made of high temperature molten glass. From home, the molten glass is fed to the spinner, cooled to the "HTV" temperature (high temperature viscosity) or to the "fibrillation" temperature, because the home is fed with hot molten glass, and the temperature of the glass in this home is above the HTV temperature, the difference in temperature between the HTV and the liquid ("? t"), the temperature that defines the limit of crystallization can be quite small in the rotary process. and marble, laces. "primary" of relatively high diameter, of the glass (the primary ones), exude from the holes located in the bottom of the bowl. Because the marble at room temperature is added continuously or in increments to the copper, there will be numerous places inside the copper where the temperature can fall below the temperature of the liquid, thermodynamically favoring the crystallization and interrupting the process. To ensure that the process is not interrupted, the glass compositions must be used, which exhibit a significant difference, minimum of 1S6.67 ° C, between the HTV temperature and the liquid. Thus, glass compositions formulated by the rotary process, which have a low? T, are not suitable for use in the copper and marble process.

The primary cords that leave the copper, in the process of copper and marble, are attenuated by the flame, rather than attenuated by a hot gas, thus exposing the glass fibers at higher temperatures than in the rotating process. These higher temperatures cause a loss of the more volatile compounds of the glass composition from the outside of the fibers, which results in a "cover" having a different composition than the interior of the fibers. As a result, the biosolubility of glass fibers, prepared by the perol and marble method, are not the same as those derived from the rotary process. As the glass fibers must necessarily dissolve from the ends of the fibers or the cylindrical exterior, a more highly resistant covering will drastically impede the bio-dissolution regime.

SUMMARY OF THE INVENTION It has surprisingly been found that glass fibers of increased biosolubility can be prepared from glass compositions suitable for the process of copper and marble, which exhibit a minimum difference of 194.43 ° C in the temperatures of HTV and liquid, and have well-defined formulations that meet both the composition of a narrow molar percentage as well as with each of the three specific "C-ratios" that govern chemical resistance, moisture resistance and biosolubility.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The glasses of the present invention have HTV and liquid temperatures, which are suitable for the production of glass fibers with the perol and marble method. These glasses must have an HTV (103 poises) of 982 to 1149 ° C, preferably 1038 to 1093 ° C and exhibit a liquid temperature, which is minimally about 194, preferably 236 and more preferably 278 ° C or more, less than that of the HTV. These characteristics are necessary to economically prepare glass fibers with a continuous base. The glass composition must be within the following composition range, in mole percent: Si02 Sß - 69. 1 A1203 0 - 2.2 RO 7 - 18 R20 9 - 20 B203 0 - 7.1 where R 0 is an alkali metal oxide and RO is an alkaline earth metal oxide. R20 is preferably N20 in its most substantial part, while RO may be MgO and / or CaO, preferably both, in a molar ratio of MgO / CaO from 1: 3 to 3: 1, more preferably 2: 3 to 3: 2 The chemical behavior of glass is dictated by three relations which must comply with the composition of the glass, C (acid), C (bio) and C (humidity). These relationships are defined conceptually as follows, all quantities are in molar percentages: C (acid) = [Si02] / ([Al203] + [B203] + [R20] + [RO]) C (bio) = ([YES02] + [A1203]) / ([B203] + [R20] + [RO]) C (humidity) = ([Si02] + [Al203] + [B203]) / ([R20] + [RO]).

In these relationships, C (acid) is the ratio that pertains to chemical resistance in acidic environments, C (bio) is the ratio that is most likely linked to biosolubility, and C (moisture) is the relationship that is related to the retention ~ of the properties in humid environments. It is convenient that C (acid) and C (humidity) be as large as possible, while C (bio) should be as low as possible. At the same time, the HTV and liquid temperature of the general composition must be suitable for the process of glass fibers. It has been found that the high biosolubility marble and pot method, while still maintaining other necessary physical properties, such as chemical resistance and moisture resistance, is obtained when C (acid) >; 1.95, C (bio) < 2.30 and C (humidity) 2.40.

Preferably, the biosoluble glass fibers of the present invention have a composition that falls within the following ranges (in molar percentages): Si02 66 - 69.0 Al203 0 - 2.2 RO 7 - 18 R20 9 - 19 B203 0 - 7.1 More preferably , the biosoluble glass fibers of the present invention have a composition that falls within the following more preferred range: Si02 66 - 68.25 A1203 0 - 2.2 RO 7 - 13 R20 11 - 18 B2O3 0 - 7.1 With respect to the performance characteristics of the glass fibers of the present invention, it is preferred that the C (acid) is greater than or equal to 2.00; C (bio) is less than or equal to 2.23, more preferably less than or equal to 2.20; and that C (humidity) is greater than or equal to 2.50, preferably greater than or equal to 2.60. As previously discussed, it is more convenient that C (acid) and C (moisture) be as high as possible. For example, C (moisture) values of 3.00 or higher are particularly preferred. It should also be noted that the various ratios of C are independent in the sense that a more preferred glass does not need to have all the "most preferred" C-ratios. Acid resistance can be measured by standard tests in the battery industry. For example, a typical test involves the addition of 5 grams of fibers of 3 μm diameter nominally in 50 ml of sulfuric acid, which has a specific gravity of 1.26. Following the reflux for 3 hours, the acid phase can be separated by filtration and analyzed for dissolved metals or other elements. The procedure used to evaluate the bio-dissolution regime is similar to that described by Law et al. (1990). The procedure consists essentially of leaching an aliquot of 0.5 gram of the candidate fibers into a synthetic physiological fluid, known as the Gamble fluid, or a synthetic extracellular fluid (SEF) at a temperature of 37 ° C and a set regimen to achieve a ratio of the flow regime to the surface area of the fibers from 0.02 cm / h to 0.04 cm / h, for a period of up to 1,000 hours. The fibers are kept in a thin layer between 0.2 μm of a polycarbonate filter medium with a plastic support mesh backing and the whole set placed inside a polycarbonate sample cell, through which the Fluid can be filtered. The pH of the fluid is regulated to 7.4 + 0.1 through the use of the positive pressure of 5% C0 / 95% of N2, through the flow system. Elemental analysis using inductively coupled plasma spectroscopy (ICP) of fluid samples, taken at specific time intervals, is used to calculate the total mass of the dissolved glass. From these data, a general regime constant can be calculated for each type of fiber in the relationship: k = [doP (l- (M / Mo) 0-5]) / 2t where k is the constant of the dissolution rate in SEF, d0 is the initial diameter of the fiber, p is the initial density of the glass comprising the fiber, M0 is the initial mass of the fibers, M is the final mass of the fibers (M / M0 ===== the remaining mass fraction) and t the time at which the data is taken. The details of the derivation of this relationship are given in Leineweber (1982) and Potter and Mattson (1991). The values for k can be supplied in ng / cm2 / h and preferably exceed a value of 150. Duplicate operations on several fibers in a given set of samples showed that the values of k are consistent within 3 percent for a given composition. The data obtained from this evaluation can be effectively correlated within the set of samples chosen - dissolution data used to derive the k were obtained only from the experimental samples of uniform diameter (3.0 μm) and under identical conditions of the surface area of the sample initial per volume of fluid per unit of time, and the permeability of the sample. The data was obtained from operations of up to 30 days, to obtain an exact representation of the dissolution by long period of the fibers. The preferred bio-dissolution rate constants in ng / cm2 / h are greater than 150 ng / cm2 / h, preferably greater than 200 ng / cm2 / h, more preferably greater than 300 ng / cm2 / h, and especially preferred higher than 400 ng / cm2 / h. Having generally described this invention, a further understanding may be obtained with reference to certain specific examples, which are provided herein for purposes of illustration only and are not intended to be limiting, unless otherwise specified.

The comparisons Compare. Cl and C2 ratios The ratios of C were calculated for a conventional C glass (chemically resistant glass) and a glass "soluble" and are set forth in Examples la and 2b in Table 1 of the E patent. U. A., No. 5,055,428. The glass composition is supplied as a percentage by weight. The HTV (103 poises) and the temperature of the liquid are as presented in the '428 patent. Table 1 As can be seen from Table 1, the C ratios of these glasses of the rotary process indicate that they must have both good performance with respect to acid resistance, moisture resistance and biosolubility. The glass of Comparative Example 2 was reported by the patent having a dissolution rate in the model physiological saline solution (composition not described) of 211 ng / cm2 / h. However, examination of the HTV and liquid temperatures revealed that they differ only by 126 and 137 ° C, respectively. Thus, these glass compositions can not be used in fibrillation by the perol and marble method. These Comparative Examples serve to illustrate the ease with which the highest biosolubility in the glass of the rotary process can be obtained. These glasses can not be used to manufacture glass fibers by the process of copper and marble. However, although this is possible, the flame attenuation and the consequent loss of the volatile oxides of the fiber surface is expected to decrease the measured biodissolution rate by a factor of approximately 2 to 4.

Examples 1 and 2 Two glass formulations were processed in marbles for use in the fibrillation of the copper and marble, and the glass fibers were prepared in a conventional manner. The formulations, C ratios, HTV (iO3 poises) and liquid temperatures, and the measured biosolubility are presented in table 2. The ingredients are in molar percentages.

Table 2 The C ratios indicate that the glasses in Table 2 will exhibit a suitable chemical resistance (both acid and moisture), as well as a high bio-dissolution. This high bio-dissolution was confirmed by real tests, being in both cases, considerably higher than 300 ng / cm2 / h.

Example 3, Compound Examples C3 and C4 A glass of the present invention was compared with two commercial glasses in their acid resistance and moisture resistance, respectively. The formulations (mole percent) are as follows.

Table 3 The acid resistance of the glass of Example 3 was compared with that of Comparative Example C3. It was noted that the glass of Comparative Example C3 meets the requirements of the ratio of C, but not with the compositional limitations. The results of the acid resistance test are presented below in Table 3a.

Table 3a To determine the resistance to moisture, a stress corrosion test was used, in which the fibers were subjected to tension by bending them in a test chamber, with controlled humidity and temperature. The fibers, which exhibited resistance to moisture, under these conditions, took longer to break. The glass of Example 3 was compared to the glass of Comparative Example C4, a glass used commercially for insulation in constructions, where compression of the insulation and storage generates the potential to break the fibers as a result. After 50 hours, only 12% of the glass of Example 3 had been broken, while all the fibers of Comparative Example C4 had failed.

Comparative Examples C5 and C6 The ratios C for the glasses of the rotary process of Example 3 of the U. A. patent were calculated.

No. 4,510,252 and Example 2 of the patent of E. U. A., No. 4,628,038. The composition, the calculated C ratios, the temperatures of the liquid and HTV (103poises) estimated, are given in Table 4, in molar percentage.

Table 4 As can be seen from the table, the acid resistance of Comparative Example C5 is expected to be low, and the bio-dilution is expected to be also low, although the glass should exhibit good resistance to moisture. However, the difference between the temperatures of the HTV (103 poises) and the liquid is only about 165 ° C and thus this glass is not suitable for use in the process of copper and marble. The glass of Comparative Example C6 exhibits a C (acid) close to an acceptable value, although the C (bio) is too high. The glass must have good resistance to moisture. However, the glass can not be used in the process of copper and marble, since the difference between the temperatures of the liquid and the HTV (103 poises) is only 97.22 ° C.

Comparative Example 7 The ratios C and the composition data (mole percent) are presented for Example 6 of the patent of E. U. A., No. 5,108,957.

Table 5 The bio-dissolution for this glass should be marginal, however, resistance to moisture and acid should be acceptable. But the difference in the temperatures of the HTV and the liquid (? T) indicates that this glass is not suitable for the fibrillation of the copper and marble method.

Examples 4 to 12 Additional glass compositions that fall within the parameters of the present invention are presented in the following table.

EXAMPLES 4 TO 12 By the term "consisting essentially of", it is understood that additional ingredients may be added, provided they do not substantially alter the nature of the composition. Substances that cause the solution to fall below 150 ng / cm2 / h or which decrease the? T to a value below 194 ° C, are substances that substantially alter the composition. Preferably, the glass compositions are free of iron oxides, lead oxides, fluorine, phosphates (P2? 5), zirconia and other expensive oxides, except as unavoidable impurities. It should be noted that while the glass compositions of the rotary process are, in general, unsuitable for the fibrillation of copper and marble, the converse is not true, and the glass compositions of the present invention will supply fibers prepared by the rotary process having even higher bio-dissolution regimes. Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made therein, without departing from the spirit or scope of the invention, as set forth in the claims.

Claims (21)

1. Glass fibers, which exhibit high chemical resistance, resistance to moisture, and biosolubility, these glass fibers are prepared from a glass composition suitable for the fibrillation of copper and marble, this composition consists essentially of, in percent molar: Si02 66 - 69.7 Al203 0 - 2.2 RO 7 - 18 R20 9 - 20 B203 0 - 7.1 Such a glass composition has a C (acid) > . 1.95, a C (bio) 2.30, a C (humidity) > 2.46, a difference,? T, between fibrillation temperatures (viscosity of 103 poises) and liquid, greater than 194 ° C and an excess bio-dissolution of 150 ng / cm2 / h, when fibrillated by the fibrillation method of copper and marble.

2. The glass fibers of claim 1, wherein the composition consists essentially of, in molar percent: Si02 66 - 69.0 Al203 0 - 2.2 RO 7 - 16 R20 9 - 19 B203 0 - 7.1

3. The glass fibers of claim 1, wherein the composition consists essentially of, in mole percent: Si02 66-68.5 A1203 0 - 2.2 RO 7 - 13 R20 11 - 18 B203 0 - 7.'l

4. The fibers of The glass of claim 1, wherein? T is at least about 236 ° C.

5. The glass fibers of claim 2, wherein? T is at least about 236 ° C.

6. The glass fibers of claim 3, wherein? T is at least about 236 ° C.

7. The glass fibers of claim 1, in which these fibers have a measured bio-dissolution rate, when fibrillated by the method of fibrilization of copper and marble, greater than 300 ng / cm2 / h.

8. The glass fibers of claim 2, wherein these fibers have a measured bio-dissolution rate, when fibrillated by the method of fibrillation of copper and marble, greater than 300 ng / cm2 / h.

9. The glass fibers of claim 3, in which these fibers have a measured bio-dissolution rate, when fibrillated by the method of fibrillation of copper and marble, greater than 300 ng / cm2 / h.

10. The glass fibers of claim 4, in which these fibers have a measured bio-dissolution rate, when fibrillated by the method of fibrillation of copper and marble, greater than 300 ng / cm2 / h.

11. The glass fibers of claim 5, in which these fibers have a measured bio-dissolution rate, when fibrillated by the method of fibrillation of copper and marble, greater than 300 ng / cm2 / h.

12. The glass fibers of claim 6, in which these fibers have a measured bio-dissolution rate, when fibrillated by the method of fibrillation of copper and marble, greater than 300 ng / cm2 / h.

13. The glass fibers of claim 1, wherein the? T is at least about 236 ° C, and the measured bio-dissolution of the fibers, prepared by the fibrillation of the copper and marble, is greater than 400 ng / cm2 / h , approximately .

14. . The glass fibers of claim 2, wherein the? T is at least about 236 ° C, and the measured bio-dissolution of the fibers, prepared by the fibrillation of the copper and marble, is greater than 400 ng / cm2 / h. , approximately .

15. The glass fibers of claim 3, wherein the? T is at least about 236 ° C, and the measured bio-dissolution of the fibers, prepared by the fibrillation of the copper and marble, is greater than 400 ng / cmz / h. , approximately.

16. The glass fibers of claim 1, wherein the value of C (acid) > . 2.00, C (bio) < . 2.23 and C (humidity) > 2.50.

17. The glass fibers of claim 1, wherein the value of C (acid) > 2.00, C (bio) < 2.20 and the C (humidity) > 2.60.

18. Fibers of glass fibrillated by the method of copper and marble and attenuated with the flame, these fibers have an external cover that lacks volatile oxides, the fibers are prepared from a glass composition comprising, in mole percent: YES02 66 - 69.0 A1203 0 - 2.2 RO 7 - 16 R20 9 - 19 B203 0 - 7.1 characterized by a C (acid) > 2.00, a C (bio) '< . 2.23, a C (humidity) = 2.50, a difference? T between the temperatures of HTV (103 poises) and of the liquid, greater than 167 ° C and the fibers exhibit a higher bio-dissolution of approximately 150 ng / cm / h.

19. The fibers of claim 18, wherein C (acid) > 2.00, the C (bio) < 2.23, C (humidity). > 2.50, the difference? T is greater than 222 ° C, and the fibers exhibit a bio-dissolution > 300 ng / cm2 / h.

20. The fibers of claim 18, wherein the glass composition comprises, in mole percent: SiO! 66 - 68.25 Al203 0 - 2.2 RO 7 - 13 R20 11 - 18 B203 0 - 7.1 C (acid 2.00, C (bio) < 2.20, C (humidity) > 2.60, the? T is higher of 222 ° C, these fibers exhibit a bio-dissolution> 300 ng / cm2 / h.

21. A fiberglass, resistant to acid and moisture, prepared from a glass composition consisting essentially of, in mole percent: Si02 66.5 - 67.8 A1203 0.5 - 1.5 B203 5.0 - 7.0 CaO 3.0 - 7.0 MgO 3.0 - 7.0 Na20 14.0 - 17.0 K20 0.1 - 0.4 in which the sum of the CaO and MgO is between approximately 8.0 and 12.0, the glass fiber exhibits a? T greater than 222 ° C and a bio-dissolution greater than or equal to approximately 350 ng / cm2 / h.