A MINERAL-FIBER COMPOSITION

Abstract: A mineral-fiber composition that is biologically degradable characterized by the following constituents in percent by weight: SiO2 40 to 67, CaO 20 to 45, MgO 0 to 12, Na2O 0 to 10, B2O3 0 to 15, Na2O + B2O3 0 to 25, P2O5 0 to 5, Al2O3 0 to 3, TiO2, Fe2O3, BaO, MnO, K2O 0 to 5.

Description: A mineral-fiber composition The present invention relates to a mineral-fiber composition that is biologically degradable. The prior art describes some mineral-fiber compositions which are said to be biologically degradable. The biological degradability of mineral-fiber compositions is of great importance because various studies point out that mineral fibers with very small diameters in the range of less than 3 microns are suspected to be carcinogenic, while biologically degradable mineral fibers of such dimensions show no carcinogenicity. However not only the biological degradability is of crucial importance but also the mechanical and thermal properties of the mineral fibers, or the products produced therefrom, and the processibility of the mineral-fiber composition. For example mineral fibers are used to a great extent for insulation purposes. In particular for application in the industrial area sufficient temperature stability of the mineral fibers is necessary. Also, the mineral-fiber composition must permit processibility by known methods for producing mineral fibers with a small diameter, for example the jet process. The invention is based on the problem of providing a novel mineral-fiber composition that is characterized by biological degradability, has good temperature stability and is easy to process. The invention is based on the finding that this problem can be solved by a mineral-fiber composition that comprises substantially silicon oxide and alkaline earth oxides and that also contains boron oxide or barium oxide. It has turned out that such mineral-fiber compositions fulfill the combination of the necessary properties, namely biological degradability, temperature stability and good processibility. The object of the invention is a mineral-fiber composition that is biologically degradable, characterized by the following constituents in percent by weight: Si0 2 40 to 67 CaO 20 to 45 MgO 0 to 12 Na 2 0 0 to 10 B 2 0 3 0 to 15 Na 2 0 + B 2 O 3 0 to 25 P2O5 0 to 5 A1 2 0 3 0 to 3 Ti0 2 , Fe 2 θ3, BaO, MnO, K 2 0 0 to 5. The inventive mineral-fiber compositions are drawable by the jet process or the rotary process. The obtained fibers have good temperature stability. Surprisingly enough, the mineral-fiber compositions show biological degradability. The mean fiber diameter is preferably 10 microns or less, and especially between 2.5 and 5 microns. The addition of boron oxide causes a lowering of the melting point and the formation of microcrystals resulting in better handling. The inventive mineral-fiber compositions preferably have the following constituents in percent by weight: SiO 2 40 to 67 CaO 20 to 45 MgO 0 to 12 Na 2 O 0 to 10 B 2 O 3 0.5 to 15 Na 2 O + B 2 O 3 1 to 15 P2θ 5 0 to 5 Al 2 O 3 0 to 3 TiO 2 , Fe 2 O 3 , BaO, MnO, K 0 0 to 5. A content of silicon oxide in the range of 53 to 58 percent by weight is particularly preferred. With respect to the boron oxide a range of 3 to 8 percent by weight is particularly preferred, in particular 4 to 6 percent is advantageous. In a preferred embodiment the aluminum oxide content can be 1 to 3 percent by weight, preferably 2 to 3 percent by weight. In another preferred embodiment, however, it is less than 1 percent by weight. A further preferred mineral-fiber composition has the following constituents in percent by weight: SiO 2 50 to 60 CaO 25 to 35 MgO 1 to 10 Na O 1 to 8 P2θ 5 0 to 3 Al 2 O 3 0 to 2 BaO 0.5 to 5. To assess biological degradability the standard powder test of the German Glass Society was used. This is an easily conducted method and gives a sufficient measure of biological degradability. The method is described in L. Springer, "Laboratoriumsbuch fur die Glasindustrie", 3rd edition, 1950, Halle/S: W. Knapp Verlag. The temperature behavior of the mineral fibers was determined by the Swedish method. In this method a silit tube furnace is used with a horizontal working tube open on both sides having a length of 350 mm and an inside diameter of 27 mm. In the center of the furnace there is a small ceramic supporting plate (30 X 20 X 3 mm) for holding the test sample. The test sample has dimensions of 12 X 12 X 12 mm or 12 mm C X 12 mm height. The bulk density is normally 100 kg/π_3. The temperature increase is 5 K/min. The change intest sample height is determined continuously with a reading optic. The invention shall be described in more detail in the following with reference to examples. Example 1 A mineral wool of the following composition in percent by weight was produced: Si0 2 50 A1 2 0 3 0.8 Fe 2 0 3 0.3 CaO 41.1 MgO 0.6 Na 2 O 0.4 K 2 O 0.1 B 2 O 3 5.2. This composition could be processed well to mineral fibers with a mean diameter of 2.7 microns by the jet process at a drawing temperature of 1360°C. An investigation according to the standard powder test of the German Glass Society yielded a value of 35 mg/kg and thus a value for high biological degradability. Determination of temperature behavior by the Swedish method yielded a temperature stability at 5% reduction in height of 740°C, which can be clearly seen from the corresponding diagram shown by way of example in the single drawing. Example 2 A mineral wool with the following composition in percent by weight was produced: SiO 2 56.5 A1 2 0 3 0.3 Fe 2 0 3 0.3 CaO 29.1 MgO 7.8 Na 0 0.5 B O 3 5.0. This composition could be processed well to mineral fibers with a mean diameter of 2.8 microns by the jet process at a drawing temperature of 1320°C. An investigation according to the standard powder test of the German Glass Society yielded a value of 39 mg/kg and thus a value for high biological degradability. Determination of temperature behavior by the Swedish method yielded a temperature stability at 5% reduction in height of 720 °C. Example 3 A mineral wool with the following composition in percent by weight was produced: SiO 2 51.5 Fe 2 O 3 0.3 Al 2 O 3 2.0 CaO 28 MgO 10 Na 2 O 6.4 K 2 O 0.5 B 2 0 3 0.5. This composition could also be processed well to mineral fibers with a mean diameter of 2.9 microns by the jet process at a drawing temperamre of 1340°C. An investigation according to the standard powder test of the German Glass Society yielded a value of 33 mg/kg and thus a value for high biological degradability. Determination of temperamre behavior by the Swedish method yielded a temperature stability at 5% reduction in height of 700°C. Example 4 A mineral wool with the following composition in percent by weight was produced: Si0 2 51.2 Fe 2 0 3 0.5 A1 2 0 3 1.9 CaO 26.8 MgO 9.3 Na 2 0 7.3 K 2 O 0.5 B 2 0 3 1.4. This composition could be processed well to mineral fibers with a mean diameter of 2.5 microns by the jet process at a drawing temperamre of 1340°C. An investigation according to the standard powder test of the German Glass Society yielded a value of 37 mg/kg and thus a value for high biological degradability. Determination of temperamre behavior by the Swedish method yielded a temperamre stability at 5% reduction in height of 700°C. Example 5 A mineral wool with the following composition in percent by weight was produced: Si0 2 56 Fe 2 0 3 0.3 A1 2 0 3 0.3 CaO 27.4 MgO 7 Na 2 0 4.5 K 2 0 0.5 Na 2 0 + K 2 O 5 BaO 4. This composition could be processed well to mineral fibers with a mean diameter of 2.7 microns by the jet process at a drawing temperamre of 1360°C. An investigation according to the standard powder test of the German Glass Society yielded a value of 35 mg/kg and thus a value for high biological degradability. Determination of temperamre behavior by the Swedish method yielded a temperamre stability at 5% reduction in height of 740°C. Example 6 A mineral wool with the following composition in percent by weight was produced: SiO 2 55.5 Fe 2 O 3 0.4 A1 2 0 3 0.5 CaO 27.1 MgO 7.5 Na 2 0 5.5 K 2 O 0.5 Na 2 0 + K 2 O 6 BaO 3. This composition could be processed well to mineral fibers with a mean diameter of 2.8 microns by the jet process at a drawing temperamre of 1350°C. An investigation according to the standard powder test of the German Glass Society yielded a value of 39 mg/kg and thus a value for high biological degradability. Determination of temperamre behavior by the Swedish method yielded a temperamre stability at 5% reduction in height of 720°C. Example 7 A mineral wool with the following composition in percent by weight was produced: Si0 2 56 A1 2 0 3 1 CaO 28.5 MgO 7 Na 0 5 BaO 2.5. This composition could be processed well to mineral fibers with a mean diameter of 2.7 microns by the jet process at a drawing temperamre of 1350°C. An investigation according to the standard powder test of the German Glass Society yielded a value of 35 mg/kg and thus a value for high biological degradability. Determination of temperamre behavior by the Swedish method yielded a temperamre stability at 5% reduction in height of 720 °C. Example 8 A mineral wool with the following composition in percent by weight was produced: Si0 2 56 A1 2 0 3 1 CaO 29 MgO 8 Na 2 O 5 BaO 1. This composition could be processed well to mineral fibers with a mean diameter of 2.8 microns by the jet process at a drawing temperamre of 1360°C. An investigation according to the standard powder test of the German Glass Society yielded a value of 39 mg/kg and thus a value for high biological degradability. Determination of temperamre behavior by the Swedish method yielded a temperamre stability at 5% reduction in height of 740°C.

Claims: Claims 1. A mineral-fiber composition that is biologically degradable, characterized by the following constiments in percent by weight: Si0 2 40 to 67 CaO 20 to 45 MgO 0 to 12 Na 2 0 0 to 10 B 2 O 3 0 to 15 Na 2 0 + B 2 0 3 0 to 25 P2θ 5 0 to 5 Al 2 O 3 0 to 3 TiO 2 , Fe 2 O 3 , BaO, MnO, κ 2 o 0 to 5. 2. The mineral-fiber composition of claim 1, characterized by the following constiments in percent by weight: SiO 2 40 to 67 CaO 20 to 45 MgO 0 to 12 Na 2 O 0 to 10 B 2 O 3 0.5 to 15 Na 2 O + B 2 O 3 1 to 15 P2O5 0 to 5 Al 2 O 3 0 to 3 Ti0 2 , Fe 2 O 3 , BaO, MnO, κ 2 o 0 to 5. 3. The mineral-fiber composition of claim 1, characterized by the following constiments in percent by weight: SiO 2 45 to 60 CaO 25 to 45 MgO 5 to 10 Na 2 0 0 to 5 B 2 0 3 1 to 15 Na 2 0 + B 2 O 3 3 to 10 P2θ 5 0 to 1 A1 2 0 3 0 to 3 Ti0 2 , Fe 2 O 3 , BaO, MnO, K 2 0 0 to 3 Fe 2 O 3 less than 1. 4. The mineral-fiber composition of any of claims 1 to 3, characterized in that the amount of silicon oxide is 53 to 58 percent by weight. 5. The mineral-fiber composition of any of claims 1 to 3, characterized in that the amount of boron oxide is 3 to 8 percent by weight, in particular 4 to 6 percent by weight. 6. The mineral-fiber composition of claim 1, characterized by the following constiments in percent by weight: SiO 2 50 to 60 CaO 25 to 35 MgO 1 to 10 Na 2 O 1 to 8 P2O5 0 to 3 Al 2 O 3 0 to 2 BaO 0.5 to 5. 7. The mineral-fiber composition of claim 6, characterized by the following constiments in percent by weight: SiO 2 52 to 58 CaO 28 to 32 MgO 5 to 10 Na 2 0 3 to 7 P2O5 0 to 1 Al O 3 0.5 to 1.5 BaO 0.5 to 3.

Inventors: HOLSTEIN WOLFGANG, LOHE PETER, MAUGENDRE STEPHANE, SCHWAB WOLFGANG, HOLSTEIN, WOLFGANG, LOHE, PETER, MAUGENDRE, STEPHANE, SCHWAB, WOLFGANG
Applicants: HOLSTEIN WOLFGANG, LOHE PETER, MAUGENDRE STEPHANE, SAINT GOBAIN ISOVER, SCHWAB WOLFGANG, HOLSTEIN, WOLFGANG, ISOVER SAINT-GOBAIN, LOHE, PETER, MAUGENDRE, STEPHANE, SCHWAB, WOLFGANG
Application year: 1995
Main classification: C03C13
IPC codes: C03C3, C03C13