MINERAL-FIBER COMPOSITIONS

Abstract: A biologically degradable mineral-fiber composition characterized by the following constituents in percent by weight: SiO2: 45 to 60, Al2O3: less than 2, CaO 7: to 18, MgO: 4 to 10, Na2O: 7 to 20, K2O: 0 to 4, B2O3: 1 to 12, P2O5: 0 to 4, diverse: 0 to 5, Na2O: + K2O: 7 to 24, CaO + MgO: more than 15.5 and up to 25, BaO: 0 to 5, TiO2: 0 to 4, Cr2O3: 0 to 1.5, Fe2O3: 0 to 3.

Description: Mineral-fiber compositions The present invention relates to a mineral-fiber com¬ position that is biologically degradable. The prior art describes some mineral-fiber compositi¬ ons which are said to be biologically degradable. The biological degradability of mineral-fiber composi¬ tions is of great importance because various studies point out that mineral fibers with very small diameters -in the range of less than 3 microns can 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, the resistance of the mineral fibers and the processibility of the mineral-fiber composition. For example mineral fibers are used to a great extent for insulation purposes . For these applications sufficient moisture-resistance is necessary. Also, the mineral-fiber composition must permit processibility by known methods for producing mineral fi¬ bers with a small diameter, for example the centrifugal technique, in particular the inner centrifugal technique (this technique is described for example in US-PS 4 203 745) . The invention is based on the problem of providing a novel mineral-fiber composition that is characterized by biological degradability, has good stability or resistance to moisture and is easy to process. The invention is based on the finding that this pro¬ blem can be solved by a mineral-fiber composition that has considerable amounts of alkali oxides and alkaline-earth oxides, and optionally phosphorus oxide. It has turned out that such a mineral-fiber compositi¬ on fulfills the combination of the necessary properties, namely biological degradability, resistance to moisture and good processibility. The object of the invention is a mineral-fiber compo¬ sition that is biologically degradable, characterized by the following constituents in percent by weight : Si0 2 45 to 60 A1 2 0 3 less than 2 CaO 7 to 18 MgO 4 to 10 Na 2 0 7 to 20 K 2 0 0 to 4 B 2 0 3 1 to 12 P 2 0 5 0 to 4 Diverse 0 to 5 Na 2 0 + K 2 0 7 to 24 CaO + MgO more than 15.5 and up to 25 BaO 0 to 5 Ti0 2 0 to 4 Cr 2 0 3 0 to 1.5 Fe 2 0 3 0 to 3. The inventive mineral-fiber compositions are proces- sible by the centrifugal technique. The obtained fibers have good resistance to moisture. Surprisingly enough, the mineral-fiber compositions show biological degradability. The mean fiber diameter is preferably 10 microns or less, and is in particular between 2.5 and 5 microns. The inventive mineral-fiber compositions preferably have the following constituents in percent by weight: Si0 2 50 to 58 A1 2 0 3 less than 2 CaO 10 to 18 MgO 4 to 8 Na 2 0 10 to 18 K 2 0 0 to 2 B 2 0 3 3 to 12 P 2 O 5 0.5 to 4 Diverse 0 to 2 Na 2 0 + K 2 0 10 to 21 CaO + MgO 16 to 24 BaO 0 to 4 Ti0 2 0 to 3 Cr 2 0 3 0 to 1 Fe 2 0 3 0 to 2. The inventive mineral-fiber compositions have in par¬ ticular the following constituents in percent by weight: SiO, 50 to 57 A1 2 0 3 0.5 to 1.5 CaO 11 to 16 MgO 4.5 to 6 Na 2 0 12 to 17 ICO 0 . 5 to 1 B 2 0 3 5 to 11 P 2 0 5 1 to 3 Diverse 0 . 5 to 1 . 0 Na 2 0 + K 2 0 11 to 17 CaO + MgO 16 to 22 BaO 0 to 3 Ti0 2 0 to 2 Cr 2 0 3 0 to 0 . 5 Fe 2 0 3 to 1 . 5 . The inventive mineral-fiber compositions preferably have less than 55% silicon dioxide. It is also particularly preferred that the compositi¬ ons contain more than 5 percent by weight, in particular more than 6 percent by weight, magnesium oxide. Barium oxide is preferably added in exchange for calcium oxide. Biological degradability can be increased by adding phosphorus pentoxide. The inventive compositions therefore preferably contain at least 0.5 percent by weight P 2 0 5 . It is advantageous to add titanium oxide, chromium oxide and/or iron oxide to reduce the corrosive properties of the melt . The moisture-resistance of the inventive mineral-fiber compositions was determined by a standard method known as the DGG method. In the DGG method 10 g finely ground mine¬ ral with a grain size between about 360 and 400 microns is held at the boiling point for five hours in 100 ml water. After quick cooling of the material the solution is filte- red and a certain volume of the filtrate evaporated to dryness . The weight of the thus obtained dry material per¬ mits the amount of mineral dissolved in the water to be calculated. The amount is stated in milligrams per gram of tested mineral. The biological degradability of the inventive mineral compositions was tested by introducing 1 g of the mineral powder, as described for the DGG method, into a physiologi¬ cal solution with the composition stated below and a pH va¬ lue of 7.4: NaCl 6 . 78 NH 4 C1 0 . 535 NaHC0 3 2 . 268 NaH 2 P0 4 H 2 0 0 . 166 (Na 3 citrate) 2H 2 0 0 . 059 Glycine 0 . 450 H 2 S0 4 0 . 049 CaCl, 0 . 022 Dynamic test conditions were selected as are described in Scholze and Conradt. The flow rate was 300 ml/day. The duration of the test was 14 days. The results are stated as percent of Si0 2 in the solution x 100 after 14 days. The invention shall be described in more detail in the following with reference to examples. Example 1 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 56 Al 2 0 3 0.5 CaO 15 MgO 4.0 Na 2 0 16.2 K 2 0 0.8 B 2 0 3 5.5 P 2 0 5 1.5 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 32 mg/g was determined. The above-described test for biological degradability yielded a value of 615. Example 2 A composition was produced with the following consti¬ tuents in percent by weight: Si0 2 54.5 A1 2 0 3 0.5 CaO 15 MgO 4.0 Na 2 0 16.2 K 2 0 0.8 B 2 0 3 5.5 P 2 0 5 3 • ° Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 32 mg/g was determined. The above-described test for biological degradability yielded a value of 690. Example 3 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 56 A1 2 0 3 0.5 CaO 13 MgO 6 Na 2 0 16.2 K 2 0 0.8 B 2 0 3 5.5 P 2 0 5 1.5 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 32 mg/g was determined. The above-described test for biological degradability yielded a value of 615. Example 4 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 54.5 A1 2 0 3 0.5 CaO 13 MgO 6 Na 2 0 16.2 K 2 0 0.8 B 2 0 3 5.5 P 2 0 5 3 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 32 mg/g was determined. The above-described test for biological degradability yielded a value of 690. Example 5 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 56 A1 2 0 3 0.5 CaO 16 MgO 6 Na 2 0 13.2 K 2 0 0.8 B 2 0 3 5.5 P 2 0 5 1.5 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 22 mg/g was determined. The above-described test for biological degradability yielded a value of 585. Example 6 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 54.5 A1 2 0 3 0.5 CaO 16 MgO 6 Na 2 0 13.2 K 2 0 0.8 B 2 0 3 5.5 2 0 5 3 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 22 mg/g was determined. The above-described test for biological degradability yielded a value of 660. Example 7 A composition was produced with the following consti¬ tuents in percent by weight: Si0 2 54.5 A1 2 0 3 1 CaO 16 MgO 6 Na 2 0 13.2 K 2 0 0.8 B 2 0 3 6.5 P 2 0 5 1.5 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 17 mg/g was determined. The above-described test for biological degradability yielded a value of 570. Example 8 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 53 A1 2 0 3 1 CaO 16 MgO 6 Na 2 0 13.2 K 2 0 0.8 B 2 0 3 6.5 P 2 0 5 3 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 17 mg/g was determined. The above-described test for biological degradability yielded a value of 645. Example 9 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 50.5 A1 2 0 3 1 - 5 CaO 16 MgO 8 Na 2 0 12.2 K 2 0 0.8 B 2 0 3 6.5 P 2 0 5 4 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 7 mg/g was determined. The above-described test for biological degradability yielded a value of 660. Example 10 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 50.5 Al 2 0 3 1.5 CaO 18 MgO 6 Na 2 0 10.7 K 2 0 0.8 B 2 0 3 8 P 2 0 5 4 Diverse 0.5. This mineral composition could be processed by the centrifugal technique . Using the above-described DGG method a value of 7 mg/g was determined. The above-described test for biological degradability yielded a value of 660. Example 11 A composition was produced with the following consti¬ tuents in percent by weight : Si0 2 55 A1 2 0 3 1 CaO 11 MgO 5 Na 2 0 14.2 K 2 0 0.8 B 2 0 3 11.5 P 2 0 5 1 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 31 mg/g was determined. The above-described test for biological degradability yielded a value of 600. Example 12 A composition was produced with the following consti¬ tuents in percent by weight: Si0 2 56.5 A1 2 0 3 0.5 CaO 11 MgO 5 Na 2 0 14.2 K 2 0 0.8 B 2 0 3 10.5 P 2 0 5 1 Diverse 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 36 mg/g was determined. The above-described test for biological degradability yielded a value of 620. Example 13 A composition was produced with the following consti¬ tuents in percent by weight: Si0 2 58.0 A1 2 0 3 0.5 CaO 13.0 MgO 7.0 Na 2 0 + K 2 0 13.5 B 2 0 3 8.0. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 21 mg/g was determined. The above-described test for biological degradability yielded a value of 515. Example 14 A composition was produced with the following consti¬ tuents in percent by weight: Si0 2 57.0 A1 2 0 3 0.5 Fe 2 0 3 1.0 CaO 13.0 MgO 7.0 Na 2 0 + K 2 0 13.5 B 2 0 3 8.0. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 22 mg/g was determined. The above-described test for biological degradibilty yielded a value of 480. Example 15 A composition was produced with the following consti¬ tuents in percent by weight: Si0 2 58.0 A1 2 0 3 0.5 CaO 9.5 MgO 7.0 Na 2 0 + K 2 0 17.0 B 2 0 3 8.0. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 36 mg/g was determined. The above-described test for biological degradability yielded a value of 550. Example 16 A composition was produced with the following consti¬ tuents in percent by weight: Si0 2 58.0 A1 2 0 3 0.5 CaO 13.0 MgO 7.0 Na 2 0 + 2 0 17.0 B 2 0 3 4.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 27 mg/g was determined. The above-described test for biological degradability yielded a value of 515. Example 17 A composition was produced with the following consti¬ tuents in percent by weight: Si0 2 57.5 A1 2 0 3 0.5 CaO 13.5 MgO 6.5 Na 2 0 + K 2 0 17.0 B 2 0 3 4.5 Cr 2 0 3 0.5. This mineral composition could be processed by the centrifugal technique. Using the above-described DGG method a value of 25 mg/g was determined. The above-described test for biological degradability yielded a value of 490.

Claims: Claims 1. A mineral-fiber composition that is biologically degradable, characterized by the following constituents in percent by weight : Si0 2 45 to 60 A1 2 0 3 less than 2 CaO 7 to 18 MgO 4 to 10 Na 2 0 7 to 20 κ 2 o 0 to 4 B 2 0 3 1 to 12 P 2 O s 0 to 4 Diverse 0 to 5 Na 2 0 + κ 2 o 7 to 24 CaO + MgO more than 15.5 and up to 25 BaO 0 to 5 Ti0 2 0 to 4 Cr 2 0 3 0 to 1.5 Fe 2 0 3 0 to 3. 2. The mineral-fiber composition of claim 1, characte¬ rized by the following constituents in percent by weight: Si0 2 50 to 58 Al 2 0 3 less than 2 CaO 10 to 18 MgO 4 to 8 Na 2 0 10 to 18 K,0 0 to 2 B 2 0 3 3 to 12 P 2 0 5 0 . 5 to 4 Diverse 0 to 2 Na 2 0 + K 2 0 10 to 21 CaO + MgO 16 to 24 BaO 0 to 4 Ti0 2 0 to 3 Cr 2 0 3 0 to 1 Fe 2 0 3 0 to 2 . 3. The mineral-fiber composition of claim 1 or 2, cha¬ racterized by the following constituents in percent by weight: Si0 2 50 to 57 A1 2 0 3 0.5 to 1.5 CaO 11 to 16 MgO 4.5 to 6 Na 2 0 12 to 17 K 2 0 0.5 to 1 B 2 0 3 5 to 11 P 2 0 5 1 to 3 Diverse 0.5 to 1.0 Na 2 0 + K 2 0 11 to 17 CaO + MgO 16 to 22 BaO 0 to 3 Ti0 2 0 to 2 Cr 2 0 3 0 to 0.5 Fe 2 0 3 0 to 1.5. 4. The mineral-fiber composition of any of claims 1 to 3, characterized in that the content of silicon dioxide is less than 55 percent by weight. 5. The mineral-fiber composition of any of claims 1 to 4, characterized in that the content of magnesium dioxide is more than 5 percent by weight. 6. The mineral-fiber composition of any of claims 1 to 5, characterized in that the content of magnesium dioxide is more than 6 percent by weight.

Inventors: BERNARD JEAN LUC, DE MERINGO ALAIN, FURTAK HANS, ROUYER ELISABETH, BERNARD, JEAN, LUC, DE MERINGO, ALAIN, FURTAK, HANS, ROUYER, ELISABETH
Applicants: BERNARD JEAN LUC, FURTAK HANS, MERINGO ALAIN DE, ROUYER ELISABETH, SAINT GOBAIN ISOVER, BERNARD, JEAN, LUC, DE MERINGO, ALAIN, FURTAK, HANS, ISOVER SAINT-GOBAIN, ROUYER, ELISABETH
Application year: 1995
Main classification: C03C13
IPC codes: C03C3, C03C13