HU216346B - Thermostable fiberisable mineral composition with high dissolution rate in biological fluids, mineral fibre material and use thereof - Google Patents

Abstract

The present invention relates to a scalable mineral composition comprising, in thermostable and high-rise biochemical cavities, and in other cases, other yoke times present in the shank: 53.5-64% w / w SiO2, 4% w / w Al2O3, 10 \ t -20t / t% CaO, 10-20% w / w MgO and 6.5-9% w / w FeO, from which FeO and Fe2O3 are given in FeO. The use of the mineral fiber produced from the preparation, and its use as heat and / or sound insulation, as well as plant growth regulating agent or as a strainer, is within the scope of the present invention. ŕ

Description

The present invention relates to heat-stable mineral compositions, in particular to heat-stable mineral compositions having a high dissolution rate in biological fluids. More particularly, the present invention relates to mineral fibers formed from mineral compositions, their use as heat and / or acoustic insulating materials, and to mineral fiber plant growth media or substrates.

Mineral fiber insulators are widely used and have long been known for such commercial products. Insulators are made of mineral raw materials, such as rocks, slag, melted, spun into fibers and held together by a binder. The binder is generally a phenol-formaldehyde resin or a urea-modified phenol-formaldehyde resin.

Mineral fiber insulators are advantageous over fiberglass insulators because of their higher fire resistance, i.e. excellent thermal stability. Glass wool is generally resistant to temperatures up to about 650 ° C, while mineral wool can withstand temperatures up to about 1000 ° C. This excellent property of mineral fiber products should be retained and even enhanced.

In recent years, health issues related to various fibrous materials, including fiber wool insulation, have received increasing attention. It is known that inhalation of certain types of fiber, such as asbestos fibers, can cause respiratory diseases such as lung cancer. This is probably because asbestos fibers can remain in the lungs for a long time. It has not yet been demonstrated that man-made fibers are the cause of respiratory or other diseases, but mineral fibers with increased solubility in biological fluids are still needed, since such fibers are expected to have a significantly shorter half-life after inhalation. .

There have been many experiments on fiberglass (MMVF) for its adverse health effects. In addition to fiber size, it is believed that the length of time the fibers remain in the lungs is an important factor in causing disease. The residence time is affected by the physical clearance of the fibers from the lungs and the rate at which the fibers dissolve.

The dissolution rate of the fibers can be tested in different ways. In vitro studies have reported that the fibers in artificial saline (Gamble's solution modified by Scholze, H. Conradt) are described in "An In Vitro Study of the Chemical Durability of Siliceous Fibers" Ann. Occ. Hyg. 31, pp. 683-692 (1977)] using conditions similar to those of the pulmonary fluids. The pH of the liquids used is 7.4 to 7.8. Carranan: The Macrophage It is known from the Review of Ultrastructure and Function, Academic Press (1973) that the pH of macrophages is different, more acidic than the lung fluid and the like.

Fiber lifetime studies, such as rat lung dissolution studies, show that the pH difference is due to different dissolution rates and, if the fibers being tested are short enough, are covered by macrophages, or the observed lower dissolution rate of cotton fibers.

WO 89/12032 discloses inorganic mineral fiber formulations which generally meet the two-hour refractory test according to ASTM E-119 and have a low lifetime in physiological saline, i.e., have a high dissolution rate. The composition of the disclosed composition varies. However, all formulations are made from pure metal oxide or less pure feedstock by adding pure oxides and are thus extremely inexpensive.

The present invention relates to a fibrous mineral composition consisting of naturally occurring cheap raw materials having a high dissolution rate and good thermal stability in biological fluids.

The present invention relates to a fiberable mineral composition which is thermally stable and has a high dissolution rate in biological fluids and which may optionally comprise, in addition to other trace oxides, the following components:

SiO ₂ 53.5-64% w / v A1 ₂ O ₃ <4% w / v CaO 10-20% w / v MgO 10-20% w / v FeO 6.5-8% w / v,

wherein the sum of FeO and Fe ₂ O _{3 is} expressed as FeO.

Surprisingly, it has been found that mineral fibers of high solubility and high thermal stability in biological fluids can be formed from naturally occurring raw materials or from other inorganic minerals consisting of chrysolite, quartz, dolomite, calcareous sandstone and iron ore, optionally completely condition into briquettes.

The compositions of the invention may be prepared, for example, from the following naturally occurring raw materials:

quartz sand about 36 wt% chrysolite sand about 17 wt% mineral cotton waste about 12 wt% iron ore about 12 wt% dolomite about 11 wt% cement about 12 wt%.

According to the present invention, the mineral composition comprises a

The total amounts of CaO, MgO, Fe ₂ O ₃ and FeO are preferably:

% w / w <CaO + MgO + FeO / Fe ₂ O ₃ <40% w / w, particularly preferred:

% w / w <CaO + MgO + FeO / Fe ₂ O ₃ <40% w / w, mainly:

t / t% <CaO + MgO + FeO / Fe ₂ O ₃ <40 t / t%.

The mineral composition of the present invention is particularly suitable for the preparation of mineral fiber by the process of WO 92/06047.

For example, in order to produce fine fibers, the process requires a viscosity of 1.5 Pa at the processing temperature. It also k2

It is desirable that the molten composition has a viscosity of at least 0.4 Pa at processing temperature.

Surprisingly, the dissolution rate of the mineral fiber composition can be increased while at the same time other required properties are not impaired. As mentioned above, the viscosity in the molten state must be within a narrow range in order to be able to produce fibrous material by conventional processing. The resulting mineral wool must have sufficient durability to maintain its physical integrity over the life of the building, ship or other application. In addition, the mineral wool produced must have sufficient thermal stability to provide the final insulation product with excellent fire resistance.

The viscosity of a molten composition of minerals depends on the total amount of silica and alumina if the total amount of silica and alumina is high, the viscosity is high, and vice versa. Thus, the viscosity represents a certain limitation on the modifiability of the composition.

It is believed that the magnesium oxide and iron (II) / ferric (III) oxide components of the mineral composition have a significant influence on the thermal stability of the mineral fiber. Iron (II) - / iron (III) oxide plays an important role as a crystalline nucleating agent in the conversion of mineral fiber material from amorphous to crystalline or pseudocrystalline when exposed to external heat such as fire. This, to some extent, limits the minimum amount of iron (II) / iron (III) oxide component in the composition. It will be appreciated that mineral fibers without iron (II) or iron (III) oxide can also withstand high temperatures at slow temperatures, as opposed to heating by rapid heat, such as external fires. As mentioned above, when exposed to fire (sudden and / or rapid warming), the structure of the material, i.e. the structure of the mineral wool, changes from an amorphous state to a crystalline state, and therefore, having regard to heat stability, the mineral fiber agent. For example, it was expected from WO 89/12032 that the presence of aluminum oxide and iron (II) / iron (III) oxide components in the mineral composition would have a significant negative effect on the dissolution rate, which will be described later.

Dissolution speed and durability are the most difficult conditions. Mineral wool should be relatively humid to the humidity at the site of application, while dissolving rapidly in the lungs. Since in both cases the fiber is exposed to water under nearly neutral acid-base conditions, it is surprising that the above condition can be achieved by modifying the formulation.

As used herein and in the claims, the term "biological fluid" refers to physiological saline or saline present in mammals or any other liquid.

Another preferred fibrous mineral composition of the present invention comprises the following components:

SiO ₂ 53.5-63% w / v ai ₂ 0 ₃ <4% w / v CaO 15-20% w / v MgO 10-15% w / v FeO 6.5-8% w / v,

wherein the total amount of FeO and Fe ₂ O ₃ is given as FeO.

The present invention also relates to mineral fibers obtained from the mineral composition of the present invention.

In a preferred embodiment of the invention, the sintering temperature of the mineral fiber material according to the invention is preferably at least 900 ° C, more preferably at least 1000 ° C, especially at least 1100 ° C.

The present invention also provides a process for increasing the rate of dissolution of a thermally stable mineral fiber material in a biological fluid comprising the use of the composition of the present invention to produce the mineral fiber material.

The fibrous material of the invention, which is thermally stable and has a high dissolution rate in biological fluids, is suitable for thermal and / or acoustic insulation purposes and / or as a growth medium or substrate for plant growth.

Another preferred fibrous mineral composition according to the invention comprises the following components:

SiO ₂ 54.5-63% w / v ai ₂ 0 ₃ 1-4% w / v CaO 15-20% w / v MgO 11-16% w / v FeO 6.5-8% w / v,

wherein the total amounts of FeO and Fe ₂ O ₃ are expressed as FeO.

Example 1

The dissolution rate and thermal stability of the mineral fibers prepared from known or comparative formulations and the composition of the present invention were investigated as described below. Fibers were prepared by melting the mineral compositions under investigation in a circular oven and weaving the fiber material into mineral wool. No binder was used.

The following mineral fiber formulations were tested: Preparation: Commercial mineral fiber formulation, manufactured by Rockwool Lapinus Β. V., Roermond, The Netherlands,

Formulations B, C and D: Comparative Formulations; Formulations E, F, G, and I: Mineral Fiber Composition of the Invention.

The components of the formulations are listed in Table 1. In addition to the components listed there were up to 2% (w / w) of other components (traces) in each fiber composition tested, which were present in the starting materials used. Examples of such components are manganese oxide, chromium oxide and various sulfur compounds. However, in Table 1, the total amount of the components is given as 100% w / v.

HU 216 346 Β

Testing methods

Dimensions of fiber samples

Samples were sieved and the fraction below 63 µm was used for analysis.

The fiber diameter distribution was determined for each sample. The diameter and length of 200 individual strands were measured with an optical microscope (1000x magnification). The specific surface area of the fiber samples was determined taking into account the fiber density.

Measurement of dissolution rate (stationary arrangement)

300 mg of fiber was placed in 500 ml of modified Gamble's solution (complexing agent) in polyethylene containers at pH 7.5. The pH was checked once a day and adjusted if necessary with HCl.

The studies were performed for 1 week. The dishes were kept in a water bath at 37 ° C and shaken vigorously twice daily. Aliquots of the solutions were taken after 1 and 4 days and analyzed for Si in a Perkin-Elmer atomic absorption spectrophotometer.

The modified Gamble's solution, pH 7.5 + 0.2, had the following composition:

MgCl ₂ -6H ₂ O g / L 0.212 NaCl 7.120 CaCl ₂ -2H ₂ O 0.029 Na ₂ SO ₄ 0.079

g / 1

Na ₂ HPO ₄ 0.148

NaHCO ₃ 1.950 (Na ₂ tartrate) -2 H ₂ O 0.180 (Na ₃ citrate) · 2 H ₂ O 0.152

90% lactic acid 0.156 glycine 0.118

Na-pyruvate 0.172 formalin 1 ml.

Calculations

The specific dissolved thickness and dissolution rate (nm / day) were calculated based on the dissolution (mesh dissolution) of SiO ₂ . The SiO ₂ content of the fibers, their specific surface area and the amount of dissolved Si were taken into account in the calculations.

thermal stability

The thermal stability, expressed as the sintering temperature of the fiber compositions A-I, was determined and tested according to the following method:

Mineral wool samples (5x5x7.5 cm) from the fiber compositions tested were placed in a pre-cooled oven at 700 ° C. After 0.5 hours, shrinkage and sintering of the samples were evaluated. In each case, the test was repeated with a fresh sample at a temperature 50 ° C higher than the previously used temperature, and the maximum furnace temperature at which sample sintering and no further shrinkage was observed was determined.

The results are shown in Table 2.

Table 7

Components in% by volume

Comparative preparations Preparations of the invention THE B C D E F G I SiO ₂ 46.8 50.8 58.6 61.3 61.5 54.9 56.4 60.2 ai ₂ o ₃ 13.2 0.8 3.7 0.8 0.7 4.0 2.7 0.3 TiO ₂ 2.9 0.1 0.5 0.2 0.2 0.6 0.5 0.1 FeO 6.3 0.1 6.0 4.1 7.2 6.8 7.3 7.9 CaO 17.2 31.0 23.6 12.8 13.1 17.2 17.0 20.0 MgO 9.6 17.0 6.8 20.3 16.9 15.3 15.1 11.1 Na ₂ O 2.8 0.1 0.2 0.1 0.1 0.5 0.4 0.1 K ₂ O 1.2 0.1 0.6 0.4 0.3 0.7 0.6 0.3

Table 2

preparation THE B C D E F G 1 Sintering temperature (° C) 1050 750 750 800 1050 1050 1100 1100 Dissolution * pH 7.5 3 45 6 32 25 12 13 20

*: Si dissolution rate (nm / day) 1 -4. Sun.

HU 216 346 Β

The test results clearly show that the fibers of the composition of the present invention have very good thermal stability, which is shown by the sintering temperatures of 900 ° C, 1050 ° C and 1100 ° C, respectively, as compared to the comparator fibers. The commercial product (Formulation A) also has good thermal stability, while Comparative Formulations B, C, and D have relatively poor thermal stability.

The studies also clearly show that the dissolution rate of the composition of the invention increased 4- to 8-fold compared to the commercial product (Preparation A).

Comparative formulations B and D have higher dissolution rates than formulations A and C. These results are not surprising since the total amount of alumina and iron (III) oxide in formulations B and D is about 1% v / v. However, the sintering temperature is unacceptably low.

Formulations D and E differ only in the amount of FeO and MgO. Composition E (FeO content 7.1% by weight) of the present invention has significantly better thermal stability than Comparative Composition D (FeO 4.2% by weight) while dissolution rates of Compositions D and E are of the same order.

Comparison of comparative formulations B and C with formulations E-I according to the invention shows that increased sintering temperatures can be achieved by reducing the CaO content.

Thus, the results show that the mineral fibers prepared from the compositions of the present invention have excellent thermal stability and high dissolution rates in biological fluids.

Example 2

Bioavailability study

The bioavailability assay, i.e., the in vivo physiological compatibility of the commercially available mineral fiber composition of Formulation A with the composition of the present invention composition of mineral fiber, was investigated.

Materials and procedure

A small fraction of each of the test samples was suspended in double-distilled water, sonicated, and filtered through a Nuclepore filter (pore size 0.2-0.4 µm). A portion of the filter was formed on an aluminum stub and sprayed with gold at a thickness of about 30 nm. Samples were analyzed using a Cambridge Stereoscan 360 Scanning Electro Microscope (SEM). The magnification was used so that both the longest fibers and the thinnest fibers can be measured with sufficient accuracy. The length and diameter of about 400 fibers from each sample were measured, as shown in Table 3.

A total of 2 mg of fiber was suspended in 0.3 ml of 0.9% NaCl solution per rat and administered in a single dose intratracheally into the lungs of female Wistar rats weighing approximately 200 g. Five animals per group were sacrificed at 2 days, 2 weeks, 1, 3.6 and 12 months.

After killing the animals, their lungs were isolated and dried in an oven at 105 ° C and then ash formed at low temperature. The procedure 15 did not affect the particle size distribution of the test substance. This was verified by comparing lung samples from animals killed 2 days after intratracheal instillation with the appropriate starting test substance (Table 3). To calculate the clearing net, a logarithmic regression analysis of the number and weight of fibers as a function of instillation to each animal was performed. The resulting 95% confidence constant purification rate constant was converted to the appropriate Ti / ₂ half-life using the equation Ti / ₂ = ln (2) / k.

Results

The results of the analysis of fibers in the pulmonary ash are shown in Tables 4 and 5. The elimination of the fibers can be described by first order kinetics, i.e. the elimination kinetics can be defined by the half-life as shown in Tables 6 and 7.

Table 7 shows that Formulation G has a significantly lower half-life than Formulation A, even with a significantly higher initial fiber diameter (Table 3.35).

Experiments with Long and Short Asbestos Fibers [John Davis: The Pathogenicity of Long versus Short Fiber Sample of Amosite Asbestos, Brit. 7 Exp Pathology 67,415-430. (1986)], it is likely that the 40 long fibers are the most biologically active.

Table 8 shows that for long fibers there is a statistically significant difference between the known commercial mineral wool (composition A) and the fibers of the invention (composition G).

Half-life determinations using only fibers longer than 5 µm provide inconclusive results, since long fiber fragments break into shorter fibers and thus increase the Ti / ₂ value of the shorter fractions.

Table 3

Particle size distribution of the test substance (measured by number of fibers)

Test substance Date of killing of animals threads number (L / D> 5) Fiber length (μιη) Thread diameter (pm) 10% < 50% < 90% < 10% < 50% < 90% < The preparation Starting material 323 3.4 6.7 15.2 1.7 0.32 0.63 1.21 1.72 2 days 702 2.9 6.8 15.9 1.9 0.27 0.62 1.19 1.95

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Table 3 (continued)

Test substance Date of killing of animals threads number (L / D> 5) Thread length (pm) Thread diameter (pm) 10% < 50% < 90% < ^σ * 10% < 50% < 90% < The preparation 1 month 724 3.0 6.9 17.1 1.9 0.24 0.62 1.24 2.10 3 months 732 3.0 7.1 17.0 2.0 0.28 0.66 1.22 1.97 6 months 784 3.5 7.3 17.0 1.8 0.29 0.66 1.24 1.89 12 months 772 3.0 6.4 14.0 1.8 0.24 0.60 1.07 2.07 Preparation G Starting material 317 4.8 9.3 23.1 1.7 0.57 1.02 1.59 1.57 2 days 631 4.1 9.3 24.0 1.9 0.35 0.87 1.56 2.05 1 month 822 4.3 10.2 24.1 2.0 0.36 0.88 1.55 2.03 3 months 768 4.0 9.3 22.6 1.9 0.37 0.84 1.54 1.91 6 months 618 4.1 8.8 19.2 1.8 0.32 0.77 1.41 2.01 12 months 746 3.3 7.6 15.7 1.9 0.25 0.69 1.30 2.17

Table 4

SEM analysis of fibers in pulmonary ash

Test substance Date of killing of animals Fibers per lung count * Fibers (10 ⁶ / lungs) * * Fibers (L> 5 pm) (10 ⁶ / lungs) Calculated fiber mass (mg) Average S.D. Average S.D. Average S.D. Average S.D. The preparation 2 days 222 11 124.1 17.0 53.1 6.3 1.67 0.30 1 month 222 11 111.9 12.3 50.4 6.7 1.64 0.48 3 months 220 8 92.0 10.8 44.9 3.3 1.41 0.29 6 months 215 5 45.2 10.0 24.1 4.5 0.69 0.06 12 months 208 12 50.8 10.5 24.5 4.7 0.69 0.26 Preparation G 2 days 222 8 61.0 9.0 39.3 6.3 1.96 0.18 1 month 220 6 47.9 4.2 31.9 2.5 1.62 0.41 3 months 216 2 41.1 3.4 25.8 1.6 1.19 0.15 6 months 217 4 24.0 6.0 14.6 4.0 0.52 0.20 12 months 199 13 17.1 5.7 10.2 3.1 0.26 0.08

Table 5

The average fiber diameter of various length fractions of the test substances in the pulmonary ash

Date of slaughter of the animals Average diameter of fractions of different lengths [pm] <2.5 pm 2.5-5pm 5-10 pm 10-20 pm 20-30 pm > 40 pm All Average S.D. Average S.D. Average S.D. Average S.D. Average S.D. Average S.D. Average S.D. The preparation 2 days 0.63 0.04 0.76 0.04 0.84 0.02 0.88 0.09 1.07 0.22 1.27 0.23 0.91 0.25 1 month 0.61 0.05 0.75 0.03 0.86 0.08 0.86 0.13 0.94 0.12 1.35 0.31 0.89 0.27 3 months 0.60 0.05 0.74 0.03 0.84 0.05 0.89 0.11 0.96 0.31 1.33 0.14 0.89 0.38 6 months 0.61 0.09 0.74 0.06 0.81 0.06 0.92 0.10 0.97 0.10 1.24 0.20 0.88 0.23 12 months 0.52 0.03 0.66 0.05 0.76 0.05 0.78 0.10 1.10 0.39 1.51 0.23 0.89 0.38

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Table 5 (continued)

Date of slaughter of the animals Average diameter of fractions of different lengths [pm] <2.5 pm 2.5-5pm 5-10 pm 10-20 pm 20-30 pm > 40 pm All Average S.D. Average S.D. Average S.D. Average S.D. Average S.D. Average S.D. Average S.D. Preparation G 2 days 0.72 0.05 0.87 0.04 0.99 0.09 1.09 0.02 1.24 0.07 1.60 0.09 1.09 0.29 1 month 0.68 0.04 0.86 0.05 0.96 0.07 1.10 0.06 1.17 0.15 1.62 0.26 1.06 0.32 3 months 0.69 0.05 0.88 0.02 0.99 0.03 1.08 0.08 1.16 0.30 1.54 0.31 1.06 0.31 6 months 0.64 0.08 0.87 0.05 0.93 0.06 0.91 0.16 1.17 0.26 1.53 0.36 1.01 0.33 12 months 0.50 0.06 0.71 0.04 0.84 0.06 0.91 0.04 1.07 0.16 1.59 0.24 0.94 0.36

Table 6

The half-life required to eliminate fibers of different lengths of test substance in pulmonary ash

Test substance Half-life (days) calculated from the number of strands of fractions of different lengths <2.5 pm 2.5-5pm 5-10 pm 10-20 pm 20-40 pm > 40 pm All Average (95% C. L.) Average (95% C. L.) Average (95% C. L.) Average (95% C. L.) Average (95% C. L.) Average (95% C. L.) Average (95% C. L.) The preparation 201 (136-379) 251 (185-392) 318 (229-520) 279 (217-391) 191 (148-271) 158 (121-227) 257 (195-376) Preparation G 241 (170-413) 219 (168-317) 211 (172-274) 185 (146-254) 108 (91-133) 100 (89-116) 196 (159-255)

Table 7

Fiber elimination half-life and 95% confidence limit (C.L.)

Half-life (days) calculated from the number of particles of fiber count (L> 5 pm, D <3 pm) the mass of the particles Average (95% C.L.) Mean (95%. C.L.) Average (95% C.L.) The preparation 257 (195-376) 291 (227-406) 249 (187-372) Preparation G 196 (159-255) 183 (151-233) 122 (105-145)

Table 8

Comparison of Ti / ₂ values (days; number of fibers)

20-40 pm Average (95% C.L.) > 40 pm Average (95% C.L.) The preparation (known as mineral wool) 191 (148-271) 158 (121-227) Preparation G (composition according to the invention) 108 (92-133) 100 (89-116)

PATENT CLAIMS

Claims (10)

PATENT CLAIMS Claims 1. A separable mineral composition which is composed of the following components, optionally in addition to other trace oxides, in thermally stable and high dissolution biological fluids: SiO ₂ 53.5-64% w / v A1 ₂ O ₃ <4% w / v CaO 10-20% w / v MgO 10-20% w / v FeO 6.5-9% w / v, wherein the total amounts of FeO and Fe ₂ O ₃ are expressed as FeO. HU 216 346 Β Mineral composition according to claim 1, characterized in that it optionally comprises, in addition to other trace oxides, the following components: SiO ₂ 53.5-62% w / v A1 ₂ O ₃ <4% w / v CaO 15-20% w / v MgO 10-15% w / v FeO 6.5-8% w / v, wherein the total amounts of FeO and Fe ₂ O ₃ are expressed as FeO. Mineral composition according to claim 1 or 2, characterized in that the total amount of CaO, MgO, Fe ₂ O ₃ and FeO is 32% w / v <CaO + MgO + FeO + + Fe ₂ O ₃ <40 t / % by weight. Mineral composition according to claim 3, characterized in that the total amount of CaO, MgO, Fe ₂ O ₃ and FeO is 35% w / v <CaO + MgO + FeO + Fe ₂ O ₃ < <40% w / v. Mineral composition according to claim 4, characterized in that the total amount of CaO, MgO, FeO and Fe ₂ O ₃ is 38% w / v <CaO + MgO + FeO + Fe ₂ O ₃ < <40 τ / τ%. 6. A mineral fiber material having a high dissolution rate in heat-stable and biological fluids, characterized in that the composition of claims 1-5. A mineral composition according to any one of the preceding claims. 5 Mineral fiber material according to claim 6, characterized in that it has a sintering temperature of at least 900 ° C, more preferably at least 1000 ° C, in particular at least 1100 ° C. A process for increasing the rate of dissolution of a thermally stable mineral fiber material in a biological fluid, characterized in that the process of any one of claims 1-5. A composition according to any one of claims 1 to 6 for use in the production of mineral fiber. A method for thermal and / or acoustic insulation, characterized in that the mineral fiber material according to claim 6 or 7 is used. Plant growth regulator medium or substrate, characterized in that the mineral fiber material according to claim 6 or 7 is used in the medium or substrate.