Glass fibres degradable in physiological medium.

PATENT OF INVENTION

No. 94,971

NAME: ISOVER SAINT-GOBAIN, French, industrial, based in Les Miroirs, 18, avenue d'Alsace, 92400 Courbe voie, France.

EPIGRAPH: PROCESS FOR OBTAINING FIBER PROBLEMS TO DECOMPOSE IN PHYSIOLOGICAL MEANS AND PERFORMING AN INSULATION PRODUCT

INVENTORS: ISABELLE COHEN - SYLVIE THELOHAN HANS FURTAK - HARMUT TIESLER

Claim of right of priority under Article 42 of the Paris Union Convention of 20 March 1883.

France, under FR 89 10834 on 11 August 1989 and FR 90 01497 on 9 February 1990.

<img file="PT94971B_D0001.tif" />

Description of the patent application on behalf of Isover Saint-Gobain, French, Industrial, established at Les Miroirs, 18, avenue d'Alsace, 32400 Courbevoie, France, for:

SUSTAINABLE GLASS FIBER PROCESS

TO DECOMPOSE IN PHYSIOLOGICAL AND CARRYING OUT

INSULATION PRODUCT

The present invention relates to the field of glass fibers; it is more precisely aimed at glass fibers whose composition is such that they degrade as long as they are in contact with a physiological medium.

Thermal and acoustic insulation of buildings is most often performed from products consisting essentially of mineral fibers such as glass fibers. The particular configuration of the places to be isolated often leads the persons in charge of placing these products to cut them in place. This operation causes the fibers to rupture and eventually some of them to disperse in the atmosphere. It follows that sometimes a fiber can be inhaled accidentally.

Although the harmfulness of inhaled fibers is not demonstrated, it makes it necessary to better protect users by offering them a product whose safety is known.

purpose of the present invention is to propose

<img file="PT94971B_D0002.tif" />

glass fibers whose composition is such that they rapidly degrade upon contact with a physiological medium.

The present invention also aims to propose fiber compositions which may be fiber-transformed using traditional techniques such as centrifugation techniques.

Glass compositions intended to be made into fibers by said internal centrifugation techniques, that is to say techniques in which the molten material contained by the centrifuge escapes through the small peripheral holes, are those for which the conditions of use are the most severe. embarrassing. In particular, they must be capable of being worked at relatively low temperatures to ensure sufficient longevity of the material and particularly of the centrifuge. In addition, certain characteristic temperatures of the glass devitrification, such as liquidus, should be markedly lower than the glass bending temperatures in order to minimize the risk of accidentally appearing crystals likely to fill the centrifuge holes.

The objects of the invention are achieved by modifying known compositions comprising essentially silica, aluminum, alkaline and alkaline earth oxides as well as boric anhydride. From such compositions, the inventors have found that decreasing the percentage of aluminum, and even suppressing this oxide, associated with the eventual presence of phosphorus pentoxide allows to obtain glasses which, in the form of fibers, rapidly degrade in physiological medium.

The glasses according to the invention on the other hand have properties which, for the main ones among them, are close to those of known glasses, so that they can be made into fibers using the classic centrifuges. It should also be noted that the glasses according to the invention, despite the possible presence of phosphorus, can be worked in ordinary furnaces without causing excessive use of refractories.

The glass fibers according to the invention have a composition comprising the following constituents in the weight ratios defined by the following limits:

<td>Si0₂</td><td> 57</td><td>The</td><td> 70</td><td>X</td>

<td>Al 2 ^ 3</td><td> 0</td><td>The</td><td> 5</td><td>X</td>

<td>Dog</td><td> 5</td><td>The</td><td> 10</td><td>X</td>

<td>MgO</td><td> 0</td><td>The</td><td> 5</td><td>X</td>

<td>Magnet₂0 +</td><td> 13</td><td>The</td><td> 18</td><td>X</td>

<td>Β₂θ3</td><td> 0</td><td>The</td><td> 12</td><td>X</td>

<td>F</td><td> 0</td><td>The</td><td> 1,5</td><td>X</td>

<td>^P2°5</td><td> 0</td><td>The</td><td> 4</td><td>X</td>

<td>Impurities</td><td></td><td></td><td> &lt; 2</td><td>X</td>

the percentage of Ρ₂θ5 being greater than 0,1 X whereas the percentage of Al 2 O 3 is equal to or greater than approximately 1 X.

The compositions thus defined may be prepared from pure constituents, but are generally obtained by melting a mixture of natural primary materials containing different impurities.

The field of preferred fiber compositions according to the invention is defined by the following two weight limit series:

y iO-7 at 68%

6th

Al 2θ3

Oa 3 to 68 to 5

<img file="PT94971B_D0003.tif" />

<td colspan="2">Dog</td><td> 5</td><td>The</td><td> 9</td><td> %</td><td> 6</td><td>The</td><td> 9</td><td>X</td>

<td>hgO</td><td></td><td> 2</td><td>The</td><td> 4</td><td>X</td><td> 2</td><td>The</td><td> 4</td><td>X</td>

<td></td><td></td><td> 14.</td><td>The</td><td> 17</td><td> %</td><td> 14</td><td>The</td><td> 17</td><td>X</td>

<td>Κ₂θ</td><td></td><td> 0</td><td>The</td><td></td><td>X</td><td> 0</td><td>The</td><td>₂</td><td>X</td>

<td>Β₂θ3</td><td></td><td> 4</td><td>The</td><td> 11</td><td> %</td><td> 4</td><td>The</td><td> 11</td><td></td>

<td>F</td><td></td><td> 0</td><td>The</td><td> 1,5</td><td> %</td><td> 0</td><td>The</td><td> 1 ,</td><td>5X</td>

<td>^P2°5</td><td></td><td> 0</td><td>The</td><td> 3</td><td></td><td> 0,5</td><td>The</td><td> 4</td><td>X</td>

<td>For</td><td>can</td><td>to be</td><td colspan="3">used</td><td colspan="3">in the techniques</td><td>in</td>

<td>centrifugation</td><td>external,</td><td>as i</td><td colspan="3">compositions</td><td>according</td><td colspan="2">with</td><td>The</td>

advantageously have a suitable viscosity at a relatively low temperature. Preferably, for these compositions the viscosity of 1000 poles corresponds to a temperature below 12000 ° C and preferably below 11500 ° C.

Another important physical characteristic for fiber production is the temperature or temperatures associated with the devitrification phenomenon, that is to say the formation of crystals in the glazing mass. Various temperatures allow characterizing this devitrification:

- the temperature at which the growth rate of the crystals is maximum,

- the temperature at which the growth rate of the crystals becomes zero and is currently called the liquidus temperature,

Generally, it is desirable that the spacing between the temperature corresponding to a viscosity of 1000 poises and the liquidus is not less than approximately 500 ° C.

The advantages of the invention are highlighted in the following detailed description which refers to examples of embodiment:

FIRST TEST SERIES

Three compositions used for the production of fibers are previously tested for comparison in subsequent degradability tests of the compositions according to the invention (see Table 1). Composition 1 is a traditional composition for the production of insulating fibers, namely by internal centrifugation techniques. Composition 2 is a usual composition for external centrifugation techniques. Composition 3 was used for gaseous draft drawing productions.

For the physiological degradability tests, the different glass compositions are mechanically stretched to a diameter of 10 micrometres according to the textile process on a single hole laboratory die.

The obtained fibers are dipped in a solution which simulates a corked physiological medium and whose chemical composition is as follows (expressed in g / 1):

<td>NaCl</td><td> 6,73</td>

<td>NH ^ Cl</td><td> 0,535</td>

<td>NaHC0₃</td><td> 2,268</td>

<td>NaHoPO ^ HoO</td><td> 0, 166</td>

<td>(Not citrate) 2HoO</td><td> 0,053</td>

<td>Wisteria</td><td> 0,450</td>

<td>H2SO4</td><td> 0,043</td>

<td>CaC 1-7,</td><td> 0,022</td>

Conducted of closed fibers, degradability test by this under the following conditions: 30 is immersed in 30 milliliters of solution maintained at 37Â ° C. C for 3, 10 and 32 and

solution is milligrams in half a day. Does the passage of each of these periods measure the concentration of silica dissolved in the solution? This concentration is expressed in microns per liter.

For additional information the hydrolytic resistance is also measured. This measurement is performed according to a DGG method. This method consists of dipping 1 gram of ground glass, the grain size of which is between 360 and 400 micrometers, in 100 milliliters of boiling water for 5 hours. After rapid cooling, the solution is filtered and a certain volume of filtrate is evaporated to dryness. 0 weight of dry matter obtained allows to calculate the amount of glass dissolved in water; This amount is expressed in milligrams per gram of glass tested.

The results of the degradability and DGG measures are presented in Table # 2. 2 for each of the compositions. The degradation of the fibers in the etching solution is found to vary greatly from one glass to another. Of these three compositions only glass No. 1 exhibits significant degradation, even if it remains weak relative to the degradation observed by the fibers made in accordance with the invention. The other two glasses are very weakly attacked.

SECOND TEST SERIES:

This series concerns different glass fiber compositions according to the invention. These compositions, shown in Table No. 3, correspond to Glasses No. 4 to 11. One of the known glasses mentioned above is taken over by comparison (Glass No. 2.1). From these glasses, the fibers with a diameter of 10 micrometers were stretched under the same conditions as those adopted during the first series of tests.

P, /

<img file="PT94971B_D0004.tif" />

The chemical resistance of these fibers in physiological medium as their hydrolytic resistance (DGG) were measured under the same conditions as described above.

The degree of fiber degradation is measured by determining the concentration of dissolved silica for different residence times in the etching solution which, for certain fibers, was 3, 6 and 10 days.

performed velocity achieved attack is not important to emphasize that the measurement being in confined medium, it is convenient to follow the degradation over time more than the value at the end of the test time. In fact, the solution is delayed because its renewal is assured. The dissolved silica concentrations measured at the beginning of the attack time better reflect the ability for fibers to degrade in physiological medium.

obtained are shown in Table No 4.

Qs results

Glasses 4, 5, 7 and 8 illustrate the influence of P2 O5 on the attack rate of the fibers, whose compositions comprise the same percentage of B-2D3. After 3 days, glasses # 2. 4 and 5, which contain a very high percentage of phosphorus, are decomposed four to five times faster than reference glass 1. For constant aluminum content, the rate of glass decomposition decreases with phosphorus content; this is what illustrates glasses 4 &amp; 7 and 8.

Glasses # 5 and 10 show the same percentage of Al2Q3 but comprise different percentages of P2O5 decomposition speed of glass # 2 10 and slightly weaker than glass # 5, but the observed difference is not so large that it can be justified by the difference between the percentages of P2O5. It appears that the strongest 82 ° glass content compensates at least in part for the decrease in the percentage of P2O5.

This influence of B0O3 is confirmed by glasses No. 9 and III, which contain a high percentage of this oxide. The first of these glasses, despite a fairly high percentage of AloOs, exhibits a good rate of decomposition. The second character is a higher decomposition rate compared to glass No. 10, which is due at the same time to the decrease in the AlO3 content and the high percentage of BoOg.

The presence of phosphorus in the glasses according to the invention always has the effect of increasing the rate of fiber decomposition in physiological medium. However, it is found that only the decrease in aluminum, and even the complete suppression of this oxide, can be the cause of a high speed. Is this what shows glass # 6 devoid of aluminum, except in the form of impurities from natural primary materials providing other constituents of glass? If the presence of phosphorus in the glasses of the invention is generally desirable, it is not indispensable when the aluminum content does not exceed approximately 1% by weight. From this percentage, it is preferable for the fiber composition to contain more than 0.1% by weight of phosphorus pentoxide. From 2% Al 2 O 3, it is desirable for the percentage of P0O5 to be at least 0.5% by weight.

In order to avoid accelerated deterioration of refractories constituting the glass melting furnaces according to the invention, it is desirable that the ^ 2 ^ 5 content ^no® ° exceeds 4%. In preferred compositions of the invention, the percentage of this oxide remains at or below approximately 355, the percentage of aluminum then not exceeding approximately 355.

The glasses according to the invention have

<img file="PT94971B_D0005.tif" />

Viscosities and devitrification characteristics comparable to those of glasses known as glass no. 1 (see tables No 5 and 6).

These glasses therefore have the advantage that they can be made into fibers from traditional installations such as those employed in the so-called internal centrifugation technique. This technique is described in numerous patents, such as US-3,02,586, US-3,304,164, US-2,949,632 or US-3,523,774. This technique consists essentially of feeding a centrifuge equipped with an open peripheral wall of a large number of holes in molten glass. Under the action of centrifugal force the molten glass passes through these holes, then is transformed into fibers under the action of hot gas jets.

The fibers thus obtained provide excellent quality fibrous products suitable for numerous applications. Thus, for example, the fibers according to the invention are advantageously used in the form of felts or geometrically well defined panels, rigidified by a polymerized binder, or in the form of tubular products for insulating the pipes. The fibers according to the invention may also be used in the form of layers bonded over the cardboard or a wire mesh, in the form of a pad, or even in bulk for filling.

<img file="PT94971B_D0006.tif" />

TABLE # 1

Known compositions (in weight percentages)

<td></td><td>Constituents</td><td>: Glass # 1</td><td>: Glass # 2</td><td>: Glass # 3:</td>

<td></td><td>Si0₂</td><td> : 65,01</td><td> : 44,50</td><td> : 59,00 :</td>

<td></td><td>Faith₂0₂</td><td> : 0,45</td><td> : 3,90</td><td> : 0,17 :</td>

<td></td><td>A l₂0₃</td><td> : 3,40</td><td> : 13,80</td><td> : 5,50 :</td>

<td></td><td>Dog</td><td> 7,00</td><td> : 27,80</td><td>: 2.0θ:</td>

<td></td><td>MgO</td><td> : 2,95</td><td> : 7,00</td><td>: θ, 30:</td>

<td></td><td>No</td><td> : 15,85</td><td> : 1,30</td><td> : 11,20 :</td>

<td></td><td>K₂0</td><td> : 0,70</td><td> : 0,60</td><td> : 1,60 :</td>

<td></td><td>B₂O₃</td><td> : 4,50</td><td></td><td> : 11,00 :</td>

<td></td><td></td><td></td><td></td><td> : 1,00 :</td>

<td></td><td>Good</td><td></td><td></td><td>: 5, Θ0:</td>

<td></td><td>ZnO</td><td></td><td></td><td> : 3,50 :</td>

FRAME NO. 2

<td></td><td>Resistance</td><td>ia quí mi ca em</td><td colspan="2">physiological environment</td><td>and in water</td><td></td>

<td></td><td>Si0₂</td><td>Glass NQ 1</td><td></td><td>Glass NQ 2:</td><td>Glass NQ 3</td><td> «</td>

<td> •</td><td>in mg / 1:</td><td></td><td> •</td><td></td><td></td><td> •</td>

<td></td><td>3 days :</td><td> 19,5</td><td></td><td> 1,3 :</td><td> 3,2</td><td> • </td>

<td></td><td>10 days :</td><td> 55,6</td><td></td><td> 2,6 :</td><td> 31,7</td><td></td>

<td></td><td>32 days as:</td><td> 117,6</td><td></td><td> 2,8</td><td> 47,1</td><td></td>

<td></td><td>DGG mg / g:</td><td> 18,00</td><td></td><td> 9,0 :</td><td> 7,5</td><td></td>

0

TABLE # 3

Weight percentage compositions

<td rowspan="2">: Consti- : tuintes</td><td colspan="2">: Glass: Glass</td><td rowspan="2">:Glass : n2 5</td><td rowspan="2">:Glass : n2 6</td><td rowspan="2">: Glass: Glass : no 27 7: no 8</td><td rowspan="2">:Glass : n2 9</td><td rowspan="2">: Glass: Glass : n2 10: n2 11</td>

<td>: π— 1</td><td>: n2 4</td>

<td>: Si0₂</td><td> :65,01</td><td> :61,51</td><td> : 65,33</td><td> :69,90</td><td> :64,95 :63,80</td><td> :59,50</td><td> :64,28 :60,90</td>

<td>: ftl₂0₃</td><td> : 3,40</td><td> : 3,40</td><td> : 2,05</td><td> : 0,13</td><td> : 3,30 : 3,30</td><td> : 4,90</td><td> : 2,10 : 1,10</td>

<td>: Dog</td><td> : 7,00</td><td> : 7,00</td><td> : 7,00</td><td> : 7,00</td><td> : 6,90 : 6,90</td><td> : 7,00</td><td> : 7,00 : 6,90</td>

<td>: MgO</td><td> : 2,35</td><td> : 2,95</td><td> : 3,00</td><td> : 2,90</td><td> : 2,90 : 2,90</td><td> : 2,95</td><td> : 2,95 : 2,85</td>

<td>: At₂0</td><td> :15,85</td><td> :15,85</td><td> :15,50</td><td> :15,60</td><td> :15,50 :15,60</td><td> :13,85</td><td> :15,85 :15,90</td>

<td>: K₂O</td><td> : 0,70</td><td> : 0,70</td><td>: θ, 08</td><td> : 0,07</td><td> : 0,60 : 0,60</td><td> : 0,70</td><td> : 0,60 : 0,60</td>

<td>: and₂O₃</td><td> : 4,50</td><td> : 4,50</td><td> : 4,25</td><td> : 4,10</td><td> : 4,70 : 4,60</td><td> : 9,75</td><td> : 5,90 :10,20</td>

<td> · ^P2°5</td><td></td><td> : 3,40</td><td> : 2,45</td><td></td><td> : 1,00 : 2,00</td><td> : 1,00</td><td> : 1,00 : 1,15</td>

<td>:others</td><td> : 0,59</td><td> : 0,69</td><td> : 0,34</td><td> : 0,30</td><td> : 0,15 : 0,30</td><td> : 0,35</td><td> : 0,32 : 0,40</td>

TABLE N2 4

Chemical resistance in physiological environment Dissolved SiO2 concentration (in mg / 1)

<td colspan="2">: Time: Glass</td><td rowspan="2">:Glass : n'2 4</td><td colspan="2">: Glass: Glass</td><td rowspan="2">:Glass : n2 7</td><td rowspan="2">:Glass : n'2 8</td><td rowspan="2">:Glass : n2 9</td><td rowspan="2">:Glass : n2 10</td><td rowspan="2">:Glass : n2 ll</td>

<td>: attack:</td><td># 1</td><td>: n2 5</td><td>: n2 6</td>

<td>&gt; : 3 days:</td><td> 19,5</td><td> : 96,3</td><td> : 83,4</td><td> :128,3</td><td> : 72,7</td><td> : 74,9</td><td>: 8Θ, 2</td><td> : 75,1</td><td> :105,0</td>

<td>: 6 days:</td><td></td><td></td><td></td><td> :149,7</td><td> :106,9</td><td> :104,8</td><td> :103,5</td><td> :105,4</td><td> :128,1</td>

<td>:10 days:</td><td> 55,6</td><td> :132,7</td><td> :132,7</td><td> :162,6</td><td> :124,1</td><td> :128,3</td><td> :119,4</td><td> :127,6</td><td> :147,6</td>

<td>: 32 days:</td><td> 117,6</td><td> :143,0</td><td> :139,0</td><td></td><td></td><td></td><td> : -</td><td></td><td></td>

<td> =========</td><td> := = = = = =</td><td> ========</td><td> :======;</td><td> ========</td><td> ========</td><td> ========</td><td> :== =====</td><td> ========</td><td> ========:</td>

1

<img file="PT94971B_D0007.tif" />

TABLE Νθ 5

Viscosity temperatures - characteristics (at 9. C)

<td colspan="3"> :===5= ========:=:=====:====</td><td colspan="7"> :==================================================</td>

<td>Mistletoe:</td><td>Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>: Glass:</td>

<td>sity:</td><td>11R 1</td><td>: ηθ 4</td><td>: ηθ 5</td><td>: n2 6</td><td>: ηθ 7</td><td>: ηθ 8</td><td>: ηθ 9</td><td>: n2 10</td><td>: n2 11:</td>

<td>logn = 3:</td><td> 1075</td><td></td><td> : 1099</td><td> : 1095</td><td> : 1092</td><td> : 1089</td><td>: 103Θ</td><td> : 1061</td><td> : 1003 :</td>

<td>logn = 2.5:</td><td> 1173</td><td></td><td> : 1201</td><td> : 1197</td><td> : 1195</td><td> : 1191</td><td> : 1133</td><td> : 1164</td><td> : 1090 :</td>

TABLE N2. 6th

Devitrification Features: To (oC): Glass: Glass: Glass: Glass: Glass: Glass: Glass: Glass: Glass:: _no2 1: ηθ 4: ηθ 5: ηθ 6: n2 7: ηθ 8: πθ 9: ηθ 10: ηθ li:

-.Liquidus: 910: -: 870: 930: 97Θ: 825: -: 870: 850:

: Vit. max: 830: -: 780: 82θ: 810: 800: -: 800: 795:

: V i t. max ::::::::::: (ju / mn): 0.65: -: 0.05: 0.51: 0.19: 0.11: -: 0.10: 0.11:

TABLE N2. 7th

Hydrolytic Resistance - DGS (in mg / g)

<td>Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td><td>:Glass</td>

<td>ηθ 1</td><td>: ηθ 4</td><td>: n'2 5</td><td>: ηθ 6</td><td>: ηθ 7</td><td>: ηθ 8</td><td>: ηθ 9</td><td>: ηθ 10</td><td>: ηθ 11</td>

<td> 18,0</td><td> : 16,0</td><td> : 25,0</td><td> : 51,0</td><td> : 19,2</td><td> : 18,7</td><td> : 16,1</td><td> : 20,5</td><td> : 32</td>

RESUME

The present invention relates to a process for obtaining glass fibers for fibers that can degrade in a physiological medium.

The process considers glass compositions which advantageously comprise the following constituents in the indicated weight ratios:

<td>S1O2</td><td> 57</td><td colspan="2">at 70</td><td>X</td>

<td>A19Q0 THE-</td><td> 0</td><td>The</td><td> 5</td><td> %</td>

<td>Dog</td><td> 5</td><td>The</td><td> 10</td><td>X</td>

<td>MgO</td><td> 0</td><td>The</td><td> 5</td><td>X</td>

<td>Na20 + KoO</td><td> 13</td><td>The</td><td> 18</td><td> %</td>

<td>B0O3</td><td> 2</td><td>The</td><td> 12</td><td>X</td>

<td>F</td><td> 0</td><td>The</td><td> 1,5</td><td>X</td>

<td>^P2°5</td><td> 0</td><td>The</td><td> 4</td><td>X</td>

<td>Impurities</td><td></td><td></td><td> 2</td><td>X</td>