WO1998047831A1 - A biodegradable mineral-fiber composition - Google Patents

A biodegradable mineral-fiber composition Download PDF

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Publication number
WO1998047831A1
WO1998047831A1 PCT/EP1998/002311 EP9802311W WO9847831A1 WO 1998047831 A1 WO1998047831 A1 WO 1998047831A1 EP 9802311 W EP9802311 W EP 9802311W WO 9847831 A1 WO9847831 A1 WO 9847831A1
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Prior art keywords
mineral
weight
temperature
composition
fiber composition
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PCT/EP1998/002311
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French (fr)
Inventor
Wolfgang Holstein
Peter Lohe
Axel Katzmann
Wolfgang Schwab
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Isover Saint-Gobain
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Publication of WO1998047831A1 publication Critical patent/WO1998047831A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C13/00—Fibre or filament compositions
    • C03C13/06—Mineral fibres, e.g. slag wool, mineral wool, rock wool
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C13/00—Fibre or filament compositions
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2213/00—Glass fibres or filaments
    • C03C2213/02—Biodegradable glass fibres

Definitions

  • a biodegradable mineral-fiber composition A biodegradable mineral-fiber composition
  • This invention relates to a biodegradable mineral-fiber composition and to mineral-wool products containing the mineral fibers having such a composition.
  • the biodegradability of mineral-fiber compositions is of great importance because various investigations indicate that mineral fibers with very small dimensions, in particular ones with a length of more than 5 ⁇ m and a diameter of less than 3 ⁇ m and a length-to-diameter ratio of more than 3:1, are suspected of being carcinogenic when they pass into the body and remain there permanently or for some time. Investigations have shown further that mineral fibers which meet the above- mentioned criteria but are degraded under physiological conditions, for example with a half-life in the range of 40 days, show no carcinogenicity.
  • the carcinogenicity of fiber dusts of natural and artificial mineral fibers is determined by TRGS 905 from the German Ministry of Labor in the version of October 1995 with reference to the composition, among other things.
  • So-called WHO fibers with a length > 5 ⁇ , a diameter ⁇ 3 ⁇ m and a length-to-diameter ratio of > 3:1 from glass, rock, slag or ceramics, are classified in various categories, being rated with reference to the so-called carcinogenicity index CI .
  • the CI value is positively influenced above all by the alkali, alkaline-earth and optionally boric oxides added as so-called fluxing agents, while the aluminum oxide added as a network former, with its double proportion by weight, is taken negatively into account.
  • Other components such as Si0 2 itself and Fe 2 0 3 , are neutral to the calculation. Setting a CI value of 40 or more is problematic for several reasons. Apart from the fact that such a composition must be realizable under economically reasonable conditions, these compositions must be easy to process and the products therefrom must meet the technical requirements. A high CI value necessitates the use of considerable quantities of fluxing agents, however, which greatly influences the properties of the glass melt.
  • Mineral-fiber compositions should meet the requirements of good processibility by established methods for producing mineral wool, in particular the jet process or Sillan process with small diameters.
  • a sufficient processing window above the liquidus temperature is required, for example a window of 80°C and a suitable viscosity of the glass melt that allows a sufficiently high throughput, on the one hand, and provides fiberizability with good wool quality, on the other hand.
  • the mechanical and thermal properties of the mineral fibers or the products therefrom are likewise of great importance.
  • Mineral wool is used for example to a great extent for insulating purposes, which is why sufficient dimensional and temperature stability are necessary in particular for use in the industrial sector. Resistance to atmospheric influences is further required in order to ensure a long life of the products.
  • the processed raw melt have a suitable viscosity allowing production of primary threads of liquid glass which are not too thin and are then fiberized by the effect of drawing-out gas streams.
  • a predetermined thickness of the primary glass threads excessive viscosity leads to deficient throughput, and deficient viscosity to an excessively fast runoff of the glass melt with further, negative effects on the fiberizing process itself.
  • Reduced thickness of the primary glass threads in turn reduces throughput and has repercussions on the fiberizing process.
  • a further prerequisite for good processibility is a sufficient interval between liquidus temperature and the temperature at which the viscosity desired for processing exists.
  • a sufficient temperature interval ensures sufficient flexibility of production conditions, in particular in terms of temperature control, and allows small deviations in the melt composition from the standard composition to be buffered.
  • Biodegradable mineral-fiber compositions are known from DE 44 27 368 Al .
  • the glass analyses known therefrom and in conjunction therewith yield suitable mineral fibers for a great variety of purposes but are based on a compromise at the expense of fiberizing.
  • Good product properties are obtained at the price of losses in production output, which have an adverse effect on the economy of the product.
  • these glass mixtures have a relatively low temperature for the viscosity number log ⁇ of 1.25, which is moreover very close to the liquidus temperature. This results in a very small processing window or the necessity of performing processing at increased temperatures and thus clearly lower viscosity.
  • the decreased working viscosity leads to a reduction in primary thread diameter, which in turn entails a throughput below the plant optimum.
  • the problem underlying the invention is therefore to provide a mineral-fiber composition that is characterized by biodegradability, has economic fiberizability, and retains the accustomed quality of the mineral-fiber products.
  • the mineral-wool products should have a temperature stability that permits them to be used in technical applications usual for rock wool .
  • a mineral-fiber composition that consists essentially of silicon dioxide and alkaline-earth oxides, has a relatively low proportion of aluminum oxide, and is defined with respect to its content of sodium and potassium oxides.
  • the mineral fibers obtained according to the invention show biodegradability by the criteria of TRGS 905 and sufficient temperature stability for insulating objects as well as weatherproofness, and can be produced by the known Sillan process at a processing temperature in the range of 1300 to 1400°C with increased throughput over known compositions.
  • inventive mineral-fiber compositions have the following components in percent by weight:
  • weight ratio Si0 2 / (Na 2 0 + K 2 0) is in the range of 12.5 to 20.0 preferred 12.6 to 19.3 and the sum of proportions by weight of the oxides of sodium, potassium, boron, calcium, magnesium and barium minus two times the proportion by weight of aluminum oxide (CI index) is in the range of 40 to 42.
  • a weight ratio Si0 2 / (Na 2 0 + K 2 0) in the range of 12.8 to 15.0 is most preferred.
  • the quantity of Fe 2 ⁇ 3 in the mineral fiber composition is preferred ⁇ 1.0 wt%.
  • the inventive mineral-fiber composition which has a CI value of 40 to 42 with a low content of aluminum oxide, is characterized by a comparatively high proportion of Si0 2 and a relatively low proportion of alkali oxides (Na 2 0 + K 2 0) coordinated therewith.
  • the preferred weight ratio Si0 2 / (Na 2 0 + K 2 0) of 12.8 to 15.0 corresponds to proportions of 3.4 to 4.5 percent by weight of Na 2 0 + K 2 0 in the composition.
  • Mineral-fiber compositions with the following components in percent by weight are particularly preferred:
  • inventive mineral-fiber compositions are based on the finding that both liquidus temperature and viscosity characteristics can be influenced in a positive way for processibility of the composition by a controlled addition of alkali oxides without impairing other properties, for example biodegradability.
  • the preferred weight ratio Si0 2 / (Na 2 0 + K 2 0) is in the range of 12.8 to 13.5 and in particular 12.9 to 13.0, corresponding to 3.9 to 4.4 percent by weight of Na 2 0 + K 2 0 and 4.1 to 4.3 percent by weight of Na 2 0 + K 2 0, respectively.
  • the inventive mineral-fiber compositions have a liquidus temperature of 1310°C.
  • the temperature at a viscosity number log ⁇ [dPas] of 1.25 is preferably higher than 1340°C, in particular about 1345°C or more.
  • inventive compositions lead to a lowering of the aluminum oxide content over conventional mixtures, in particular to values below 2.0 percent by weight, which also positively influences the CI value.
  • What is essential is that the desired properties, in particular temperature stability, are obtained with the fibers gained from these compositions or the insulating materials therefrom.
  • the invention depends on a careful coordination of the individual components in order to reach the goals of the invention.
  • the relatively high content of Si0 2 provides temperature stability and influences viscosity in the desired way.
  • the coordination of the alkali and alkaline- earth admixtures results altogether in a surprisingly low liquidus temperature.
  • the inventive mineral-fiber compositions can be melted in standard melting tanks at melting temperatures of 1380 to 1450 °C. A homogeneous melt is obtained, which is a prerequisite for continuous production and constant product quality as well as a uniform production process. The homogeneity of the glass melt ensures reproducibility of the fiberizing process and leads to constant good thermal and mechanical product properties.
  • the inventive mineral-fiber compositions are processed in the usual way into mineral-wool products such as insulating mats and shaped articles.
  • the composition stands for a CI value of 40.1.
  • the ratio Si0 2 / (Na 2 0 + K 2 0) is 12.93.
  • the composition was melted at a temperature of about 1430°C to a homogeneous melt.
  • the liquidus temperature is 1315°C.
  • the viscosity number log ⁇ of 1.25 is reached at a temperature of 1345°C.
  • the molten material was guided through platinum nozzles with a bore diameter enlarged by about 15%, and the primary threads of molten glass fiberized in a highspeed air stream into fibers with a mean diameter in the range of 2.0 to 10 ⁇ m.
  • the output based on bore diameter was about 32 kg a day.
  • the viscosity of the glass melt is shown as a function of temperature in Fig. 1.
  • Table 1 shows some preferred compositions of a biodi- gradable mineral-fiber accoding to the present invention.
  • the Compositions may include small quantities of usual impurities
  • Example 1 a mineral-fiber composition according to DE 44 27 368 with the following components was processed into glass wool:
  • the CI value of the composition is 40.8, the ratio Si0 2 / (Na 2 0 + K 2 0) is 12.68.
  • the liquidus temperature of the homogeneous melt is at a temperature of about 1320°C, viscosity value log ⁇ of 1.25 is reached at a temperature of 1325°C.
  • the glass melts used therein have virtually parallel viscosity curves, whereby that of the inventive melt intersects the characteristic line log ⁇ [dPas] of 1.25 at a 20°C higher temperature. Since the liquidus temperature is simultaneously below that of the comparative example melt, a processing window situated very favorably with respect to characteristic viscosity opens above the liquidus temperature. The relatively great interval from the liquidus temperature provides the possibility of fine adjustment with respect to both the temperature of the glass threads and the viscosity, and also allows small fluctuations in the glass melt composition to be compensated.
  • the thermal behavior of the mineral fibers was determined by the so-called "Swedish method.”
  • This method uses a silit pipe furnace with a horizontal working pipe open on both sides with a length of 350 mm and an inside diameter of 27 mm. In the center of the furnace there is a ceramic supporting plate with dimensions of 30 x 20 x 3 mm for positioning the test sample.
  • the test sample has dimensions of 12 x 12 x 12 mm or 12 mm 0 x 12 mm height.
  • the gross density is normally 100 kg/m 3 .
  • the temperature increase is 5 K/min.
  • the change in test sample height is determined continuously with a reading optic.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Glass Compositions (AREA)
  • Biological Depolymerization Polymers (AREA)

Abstract

The invention relates to a biodegradable mineral-fiber composition with the following components in percent by weight: SiO2 51.5 to 57.0, Al2O3≤2.0, Fe2O3≤1.5, CaO 28.0 to 33.0, MgO 8.0 to 11.0, Na2O 2.4 to 4.4, K2O≤2.0 wherein the weight ratio SiO2/(Na2O + K2O) is in the range of 12.5 to 20.0 and the viscosity log θ [dPas] of 1.25 is at a temperature of 1340 to 1350 °C or more, and the sum of proportions by weight of the oxides of sodium, potassium, boron, calcium, magnesium and barium minus two times the proportion by weight of aluminum oxide (CI index) is in the range of 40 to 42.

Description

A biodegradable mineral-fiber composition
This invention relates to a biodegradable mineral-fiber composition and to mineral-wool products containing the mineral fibers having such a composition.
Mineral fibers that can be biodegraded under physiological conditions are described often in the prior art.
The biodegradability of mineral-fiber compositions is of great importance because various investigations indicate that mineral fibers with very small dimensions, in particular ones with a length of more than 5 μm and a diameter of less than 3 μm and a length-to-diameter ratio of more than 3:1, are suspected of being carcinogenic when they pass into the body and remain there permanently or for some time. Investigations have shown further that mineral fibers which meet the above- mentioned criteria but are degraded under physiological conditions, for example with a half-life in the range of 40 days, show no carcinogenicity.
A trend has therefore developed recently toward mineral- fiber compositions with good biodegradability.
The carcinogenicity of fiber dusts of natural and artificial mineral fibers is determined by TRGS 905 from the German Ministry of Labor in the version of October 1995 with reference to the composition, among other things. So-called WHO fibers with a length > 5 μ , a diameter < 3 μm and a length-to-diameter ratio of > 3:1 from glass, rock, slag or ceramics, are classified in various categories, being rated with reference to the so-called carcinogenicity index CI . The classification depends on the sum of the mass contents for (in percent by weight) of the oxides of sodium, potassium, boron, calcium, magnesium, barium reduced by two times the mass content of aluminum oxide according to the formula CI = Σ Na, K, B, Ca, Mg, Ba oxides - 2 x Al oxide.
As a result glassy WHO fibers with a carcinogenicity index CI < 30 are classified in category 2, ones with CI > 30 and < 40 in category 3, while ones with a CI > 40 are not classified as carcinogenic. Accordingly, mineral-fiber compositions with a CI following the above definition of 40 or more are deemed non- carcinogenic.
As stated, the CI value is positively influenced above all by the alkali, alkaline-earth and optionally boric oxides added as so-called fluxing agents, while the aluminum oxide added as a network former, with its double proportion by weight, is taken negatively into account. Other components, such as Si02 itself and Fe203, are neutral to the calculation. Setting a CI value of 40 or more is problematic for several reasons. Apart from the fact that such a composition must be realizable under economically reasonable conditions, these compositions must be easy to process and the products therefrom must meet the technical requirements. A high CI value necessitates the use of considerable quantities of fluxing agents, however, which greatly influences the properties of the glass melt.
Mineral-fiber compositions should meet the requirements of good processibility by established methods for producing mineral wool, in particular the jet process or Sillan process with small diameters. A sufficient processing window above the liquidus temperature is required, for example a window of 80°C and a suitable viscosity of the glass melt that allows a sufficiently high throughput, on the one hand, and provides fiberizability with good wool quality, on the other hand.
The mechanical and thermal properties of the mineral fibers or the products therefrom are likewise of great importance. Mineral wool is used for example to a great extent for insulating purposes, which is why sufficient dimensional and temperature stability are necessary in particular for use in the industrial sector. Resistance to atmospheric influences is further required in order to ensure a long life of the products.
As far as the processibility of the mineral-fiber compositions is concerned, it is essential for example for performing the jet process that the processed raw melt have a suitable viscosity allowing production of primary threads of liquid glass which are not too thin and are then fiberized by the effect of drawing-out gas streams. At a predetermined thickness of the primary glass threads, excessive viscosity leads to deficient throughput, and deficient viscosity to an excessively fast runoff of the glass melt with further, negative effects on the fiberizing process itself. Reduced thickness of the primary glass threads in turn reduces throughput and has repercussions on the fiberizing process.
A further prerequisite for good processibility is a sufficient interval between liquidus temperature and the temperature at which the viscosity desired for processing exists. A sufficient temperature interval ensures sufficient flexibility of production conditions, in particular in terms of temperature control, and allows small deviations in the melt composition from the standard composition to be buffered.
Biodegradable mineral-fiber compositions are known from DE 44 27 368 Al . The glass analyses known therefrom and in conjunction therewith yield suitable mineral fibers for a great variety of purposes but are based on a compromise at the expense of fiberizing. Good product properties are obtained at the price of losses in production output, which have an adverse effect on the economy of the product. In particular, these glass mixtures have a relatively low temperature for the viscosity number log η of 1.25, which is moreover very close to the liquidus temperature. This results in a very small processing window or the necessity of performing processing at increased temperatures and thus clearly lower viscosity. The decreased working viscosity leads to a reduction in primary thread diameter, which in turn entails a throughput below the plant optimum.
The problem underlying the invention is therefore to provide a mineral-fiber composition that is characterized by biodegradability, has economic fiberizability, and retains the accustomed quality of the mineral-fiber products. Good economic fiberizability requires in particular a sufficient interval between the temperature at which glass viscosity η has a value of about 18 dPas (log η = 1.25) and the liquidus temperature, an optimal thickness of the primary threads and thus improved productivity of the total plant. Further the mineral-wool products should have a temperature stability that permits them to be used in technical applications usual for rock wool .
It has been found that this problem can surprisingly be solved by a mineral-fiber composition that consists essentially of silicon dioxide and alkaline-earth oxides, has a relatively low proportion of aluminum oxide, and is defined with respect to its content of sodium and potassium oxides.
The mineral fibers obtained according to the invention show biodegradability by the criteria of TRGS 905 and sufficient temperature stability for insulating objects as well as weatherproofness, and can be produced by the known Sillan process at a processing temperature in the range of 1300 to 1400°C with increased throughput over known compositions.
The inventive mineral-fiber compositions have the following components in percent by weight:
Si02 51 . 5 to 57 . 0
A1203 < 2 . 0
Fe203 < 1 . 5
CaO 28 . 0 to 33 . 0
MgO 8 . 0 to 11 . 0
Na20 2 . 4 to 4 . 4
K20 < 2 . 0
wherein the weight ratio Si02/ (Na20 + K20) is in the range of 12.5 to 20.0 preferred 12.6 to 19.3 and the sum of proportions by weight of the oxides of sodium, potassium, boron, calcium, magnesium and barium minus two times the proportion by weight of aluminum oxide (CI index) is in the range of 40 to 42.
A weight ratio Si02/ (Na20 + K20) in the range of 12.8 to 15.0 is most preferred.
The quantity of Fe2θ3 in the mineral fiber composition is preferred < 1.0 wt%. Further components, such as P205, Ti02, BaO, MnO or the like, as are usually employed in small quantities in mineral- fiber compositions, can be present in quantities of up to 5 wt% in individual parts or as a sum.
The inventive mineral-fiber composition, which has a CI value of 40 to 42 with a low content of aluminum oxide, is characterized by a comparatively high proportion of Si02 and a relatively low proportion of alkali oxides (Na20 + K20) coordinated therewith. The preferred weight ratio Si02/ (Na20 + K20) of 12.8 to 15.0 corresponds to proportions of 3.4 to 4.5 percent by weight of Na20 + K20 in the composition. By this combination one ensures a favorable liquidus temperature, a viscosity suitable for fiberizing power and a safe interval between characteristic-viscosity temperature and liquidus temperature. The mineral fibers produced therewith reach a sufficient temperature stability of about 700°C.
Mineral-fiber compositions with the following components in percent by weight are particularly preferred:
Si02 53 . 0 to 56 . 0
A1203 1 . 0 to 1 . 8
Fe203 0 . 6 to 1 . 0
CaO 28 . 0 to 30 . 0
MgO 8 . 0 to 11 . 0
Na20 3 . 5 to 4 .2
K20 < 0 . 5
The inventive mineral-fiber compositions are based on the finding that both liquidus temperature and viscosity characteristics can be influenced in a positive way for processibility of the composition by a controlled addition of alkali oxides without impairing other properties, for example biodegradability.
The preferred weight ratio Si02/ (Na20 + K20) is in the range of 12.8 to 13.5 and in particular 12.9 to 13.0, corresponding to 3.9 to 4.4 percent by weight of Na20 + K20 and 4.1 to 4.3 percent by weight of Na20 + K20, respectively. The inventive mineral-fiber compositions have a liquidus temperature of 1310°C. The temperature at a viscosity number log η [dPas] of 1.25 is preferably higher than 1340°C, in particular about 1345°C or more.
The inventive compositions lead to a lowering of the aluminum oxide content over conventional mixtures, in particular to values below 2.0 percent by weight, which also positively influences the CI value. What is essential is that the desired properties, in particular temperature stability, are obtained with the fibers gained from these compositions or the insulating materials therefrom.
Altogether the invention depends on a careful coordination of the individual components in order to reach the goals of the invention. The relatively high content of Si02 provides temperature stability and influences viscosity in the desired way. The coordination of the alkali and alkaline- earth admixtures results altogether in a surprisingly low liquidus temperature.
The inventive mineral-fiber compositions can be melted in standard melting tanks at melting temperatures of 1380 to 1450 °C. A homogeneous melt is obtained, which is a prerequisite for continuous production and constant product quality as well as a uniform production process. The homogeneity of the glass melt ensures reproducibility of the fiberizing process and leads to constant good thermal and mechanical product properties.
The inventive mineral-fiber compositions are processed in the usual way into mineral-wool products such as insulating mats and shaped articles.
The invention will be explained more closely by the following examples.
Example 1
By the Sillan process a mineral wool was produced with the inventive composition in percent by weight stated below:
Si02 54.3 A1203 1.6 Fe203 0.8
CaO 29.6
MgO 9.5
Na20 3.9
K20 0.3
The composition stands for a CI value of 40.1. The ratio Si02/ (Na20 + K20) is 12.93.
The composition was melted at a temperature of about 1430°C to a homogeneous melt. The liquidus temperature is 1315°C. The viscosity number log η of 1.25 is reached at a temperature of 1345°C. The molten material was guided through platinum nozzles with a bore diameter enlarged by about 15%, and the primary threads of molten glass fiberized in a highspeed air stream into fibers with a mean diameter in the range of 2.0 to 10 μm. The output based on bore diameter was about 32 kg a day.
The viscosity of the glass melt is shown as a function of temperature in Fig. 1.
Examples 2 to 5
Table 1 shows some preferred compositions of a biodi- gradable mineral-fiber accoding to the present invention.
Table 1
Example 2 Example 3 Example 4 Example 5
Si02 55.8 54.1 54.6 54.1
A1203 1.1 1.4 1.3 1.6
Fe203 0.7 1.3 1.0 0.8
CaO 29.2 30.6 31.3 29.6
MgO 9.1 9.6 8.5 9.4
Na20 3.8 2.6 3.0 3.9
K20 0.2 0.2 0.1 0.4
Si02/ 14 19.2 17.6 12.6
(Na20 + K20) KI 40 . 1 40 . 2 40 . 3 40 . 1
The Compositions may include small quantities of usual impurities
Comparative Example 1
In accordance with Example 1 a mineral-fiber composition according to DE 44 27 368 with the following components was processed into glass wool:
Si02 50 . 7
A1203 2 . 5
Fe203 1 . 0
CaO 30 . 8
MgO 11 . 0
Na20 3 . 4
K20 0 . 6
The CI value of the composition is 40.8, the ratio Si02/ (Na20 + K20) is 12.68. The liquidus temperature of the homogeneous melt is at a temperature of about 1320°C, viscosity value log η of 1.25 is reached at a temperature of 1325°C.
Processing of this melt was possible only out of platinum nozzles with a maximum diameter of 1.1 mm, whereas the invention now permits 1.3 mm. In the comparative example the output based on bore diameter was about 27 kg a day.
The viscosity of the glass melt as a function of temperature is plotted in Fig. 1 for comparison.
Comparison of the two examples shows that the glass melts used therein have virtually parallel viscosity curves, whereby that of the inventive melt intersects the characteristic line log η [dPas] of 1.25 at a 20°C higher temperature. Since the liquidus temperature is simultaneously below that of the comparative example melt, a processing window situated very favorably with respect to characteristic viscosity opens above the liquidus temperature. The relatively great interval from the liquidus temperature provides the possibility of fine adjustment with respect to both the temperature of the glass threads and the viscosity, and also allows small fluctuations in the glass melt composition to be compensated.
Altogether the invention permits an about 15% increase in the daily production of the same plant. The essential properties of the mineral-wool insulating materials produced therewith, such as application temperature, remain virtually unchanged, which is shown in Fig. 2.
The thermal behavior of the mineral fibers was determined by the so-called "Swedish method." This method uses a silit pipe furnace with a horizontal working pipe open on both sides with a length of 350 mm and an inside diameter of 27 mm. In the center of the furnace there is a ceramic supporting plate with dimensions of 30 x 20 x 3 mm for positioning the test sample. The test sample has dimensions of 12 x 12 x 12 mm or 12 mm 0 x 12 mm height. The gross density is normally 100 kg/m3. The temperature increase is 5 K/min. The change in test sample height is determined continuously with a reading optic.
The determination of thermal behavior by the Swedish method yielded a temperature stability at 5% height reduction of about 705°C, which is clearly recognizable from the graph shown in Fig. 2.

Claims

Claims
1. A biodegradable mineral-fiber composition, characterized by the following components in percent by weight:
Si02 51 . 5 to 57 . 0
A1203 < 2 . 0
Fe203 < 1 . 5
CaO 28 . 0 to 33 . 0
MgO 8 . 0 to 11 . 0
Na20 2 . 4 to 4 . 4
K20 < 2 . 0
wherein the weight ratio Si02/ (Na20 + K20) is in the range of
12.5 to 20.0 and the viscosity log ╬╖ [dPas] of 1.25 is at a temperature of 1340 to 1350┬░C or more, and the sum of proportions by weight of the oxides of sodium, potassium, boron, calcium, magnesium and barium minus two times the proportion by weight of aluminum oxide (CI index) is in the range of 40 to 42.
2. The mineral-fiber composition of claim 1 , characterized in that the ratio Si02/ (Na20 + K20) is in the range of
12.6 to 19.3
3. The mineral-fiber composition of claim 1, characterized in that the ratio Si02/ (Na20 + K20) is in the range of 12.8 to 15.0.
4. The mineral-fiber composition of one of the above claims, characterized by a liquidus temperature of 1310 to 1320┬░C.
5. The mineral-fiber composition of one of the above claims with the following composition in percent by weight:
Si02 53.0 to 56.0
A1203 1.0 to 1.8
Fe203 0.6 to 1.3
CaO 28.0 to 31.5
MgO 8.5 to 10.0 Na20 2.5 to 4.0
K20 < 0.5
6. A mineral-wool product containing mineral fibers with the composition of one of the above claims.
PCT/EP1998/002311 1997-04-19 1998-04-20 A biodegradable mineral-fiber composition WO1998047831A1 (en)

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EP97106514.9 1997-04-19
EP97106514A EP0872458A1 (en) 1997-04-19 1997-04-19 Mineral fibre composition

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CN110316969A (en) * 2019-07-08 2019-10-11 四川谦宜复合材料有限公司 A kind of agricultural rock wool of natural degradation and preparation method thereof

Citations (2)

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Publication number Priority date Publication date Assignee Title
WO1995031410A1 (en) * 1994-05-17 1995-11-23 Isover Saint-Gobain A mineral-fiber composition
WO1996030314A1 (en) * 1995-03-31 1996-10-03 Isover Saint-Gobain A mineral fiber composition

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Publication number Priority date Publication date Assignee Title
WO1995031410A1 (en) * 1994-05-17 1995-11-23 Isover Saint-Gobain A mineral-fiber composition
WO1996030314A1 (en) * 1995-03-31 1996-10-03 Isover Saint-Gobain A mineral fiber composition

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