WO2002026653A1

WO2002026653A1 - Mineral wool with enhanced durability

Info

Publication number: WO2002026653A1
Application number: PCT/FR2001/002830
Authority: WO
Inventors: Isover Saint-Gobain
Original assignee: Mahieuxe, Bruno
Priority date: 2000-09-27
Filing date: 2001-09-12
Publication date: 2002-04-04
Also published as: AU9001101A

Abstract

The invention concerns a method for enhancing the mechanical strength after ageing, in particular in humid medium, of an insulating product, in particular for heat and/or sound insulation, based on mineral wool provided with sizing, which consists in incorporating at least a sulphite and/or at least a precursor thereof in the sizing composition which contains in particular a phenolic resin, provided that said sulphite does not react with formaldehyde into a hygroscopic product. The presence of at least a sulphite and/or precursor(s) thereof enables to reduce significantly loss of mechanical strength after ageing. The sizing composition advantageously comprises at least a sulphite and/or at least a precursor thereof. The invention is useful for producing insulating products designed to be exposed to atmospheric condensation and/or based on mineral wool with lower hydrolytic resistance.

Description

MINERAL WOOL WITH IMPROVED DURABILITY

The present invention relates to techniques for manufacturing insulating products, in particular thermal and / or acoustic, based on mineral wool. It relates more particularly to the improvement of the sizing of the wool constituting such a product, so as to improve the mechanical strength after aging of the latter, in particular in a humid environment.

These products, which can be based on glass wool or rock wool, are usually in the form of coiled felts, more or less rigid panels, shells or even veils.

The manufacturing of these insulating products includes the following stages:

- the mineral composition of glass or rock is melted in a suitable oven,

- the molten mineral material is brought to a fiberizing device,

the molten material is transformed into filaments, in particular by the known technique of centrifugal drawing on rotors or in pierced plates, the filaments being generally drawn under the effect of a gas stream,

- A sizing composition is sprayed onto the wool thus formed containing a thermosetting resin,

- the glued wool is collected on a receiving member in the form of a sheet,

- The sheet is subjected to a heat treatment aimed at hardening the resin and the sheet is put into the desired shape.

The properties desired for the final product depend on each particular application, but it is generally sought to obtain, in addition to the insulating properties of the product, a certain number of mechanical characteristics, such as dimensional stability, resistance to puncture, to tearing, tensile, compression.

On the one hand, it is important that these properties are good after the manufacture of the product until it is used to ensure good conditions of installation on the site. The product is then stored in packaged, compressed form, for periods which can extend up to three to six months in a more or less humid atmosphere subject to bad weather, especially rain. It is also desirable that these properties remain good for a certain time once the product is in place, to guarantee a sufficient lifetime of the product. Unfortunately, it sometimes happens that a loss of mechanical properties of these products is observed after aging, in particular when they have been exposed to humidity, in particular under conditions of high atmospheric condensation, for example for products fitted to roofs. and which undergo significant thermal cycles. For example, care must also be taken to avoid such losses when the composition of the mineral wool is particularly sensitive to water, for example when it is a mineral wool capable of dissolving in a physiological medium.

Document WO-A-97/21636 proposes improving the resistance to aging in the presence of atmospheric moisture of artificial mineral fibers of the soluble type in physiological medium (solubility of at least 20 nm / day at pH 7.5 to 37 ° C) by forming a coating on the fibers comprising an ammonium or ammonium (hydrogen) phosphate salt quaternary or alkali metal, preferably diammonium hydrogen phosphate or ammonium dihydrogen phosphate.

The resistance to aging in a humid environment is estimated in this document, by deducing from pH measurements the rate of dissolution of the fibers in immersion tests simulating accelerated aging under normal conditions of use. The pH measurement may be supplemented by observation under the microscope of fiber erosion.

However, this treatment proves to be insufficient with regard to preserving the mechanical properties of the product after exposure to the humid environment: by practicing mechanical resistance tests on these mineral wool-based products after accelerated aging in the wet environment, the present inventors have observed that a phosphate such as diammonium hydrogen phosphate had even a negative effect on the mechanical properties after aging in a humid environment, in the sense that the losses of properties were amplified.

According to another approach, patent FR 2 782 711 describes the improvement in mechanical strength after aging in a humid environment of a mineral wool provided with a sizing based in particular on a phenolic resin, by means of the addition of '' a sizing latex during the manufacture of mineral wool. This solution is technically efficient, but the relatively high cost of the recommended latex has encouraged the search for other ways.

On the other hand, US Pat. No. 5,578,371 mentions bisulfites such as ammonium bisulfite as additives of phenol / formaldehyde binders for mineral wools in order to reduce the emission of formaldehyde and ammonia. To this end, sodium sulfite is also mentioned only under acidic conditions, that is to say as a bisulfite precursor, it being specified that sodium sulfite as such does not reduce formaldehyde emissions and can increase ammonia.

Patent FR 2 788 514 describes the ability of ammonium sulfite to trap formaldehyde in a resin phenol / formaldehyde, therefore also to limit emissions.

The object of the invention is to obviate the aforementioned drawbacks and to improve the mechanical strength after aging, in particular in a humid environment, of insulation products based on mineral wool, or in other words to make it possible to reduce the loss of properties. mechanics of these products after aging, in particular in a humid environment.

This object, as well as others which will appear subsequently, has been achieved according to the invention by adding at least one sulfite and / or at least one precursor thereof to the sizing during the manufacture of the products, being understood that said sulfite does not react with formaldehyde into a hygroscopic product.

In this regard, the subject of the invention is a method for improving the mechanical resistance after aging, in particular in a humid environment, of an insulating product, in particular thermal and / or acoustic, based on mineral wool provided with a sizing comprising a thermosetting resin, in particular a phenolic resin, process in which at least one sulfite and / or at least one precursor thereof is added to the sizing during the manufacture of the product, it being understood that said sulfite does not react with the formaldehyde into a hygroscopic product.

This latter proposition means, within the meaning of the invention, that the product of the reaction of the sulfite with formaldehyde must have a relatively low hygroscopic character. Some examples of suitable sulfites are ammonium sulfite, calcium sulfite, magnesium sulfite ... Sodium sulfite, reacting with formaldehyde to a salt very soluble in water, and producing soda , not suitable: it prevents cross-linking of the polymer from occurring normally.

Quite surprisingly, it has been observed that if, in many cases, the addition of such a sulfite to the sizing did not modify the mechanical properties at all, or even degraded these properties just after manufacture, it was possible to remarkably reduce the loss of properties after aging, in particular in a humid environment, by compared to a similar product that does not contain sulfite (standard product) and achieve a higher level of final performance after aging than the standard product.

All known sulfite precursors can be used. In the case of ammonium sulfite, for example, these terms most often denote a mixture of ammonium bisulfite and ammonia. However, in view of the toxicity of ammonium bisulfite, its presence in the final product should be avoided. According to the invention, the following are added to the sizing:

- or only at least one sulfite; - either only one or more precursors thereof;

- either one or the other.

It is specified that the addition according to the invention of at least one sulfite and / or at least one precursor thereof does not modify the pregelling character of the sizing. In the context of the invention, ammonium sulfite is preferred.

The proportion of sulfite added and / or formed by the reaction of its added precursors need not be very large in order to reach a satisfactory level of improvement in the mechanical strength of the products. In general, the weight share of the sulfite introduced and / or coming from the reaction of said precursor (s) can advantageously be chosen to be less than 20% relative to the weight of dry phenolic resin and urea, and in particular of the order of 0 , 01 to 10%. Frequently a proportion of 2% is sufficient, effects which can already be observed in certain cases with proportions as low as 0.1%, while it can be considered that additions of less than 0.01% would not usefully improve the mechanical behavior of the insulating product over time.

As regards the mode of introduction of the sulfite as such or in the form of precursor (s), the following alternative embodiments may be mentioned.

In a first embodiment, the sulfite and / or at least one precursor thereof are mixed with the constituents of the sizing during the formulation of the latter, then this composition is applied modified sizing, in the usual way on mineral wool.

In this regard, the subject of the invention is also a sizing composition for insulating product, in particular thermal and / or acoustic, with improved mechanical resistance after aging, in particular in a humid environment, comprising a thermosetting resin and at least one sulfite and / or at least one precursor thereof.

The basic formulation of the sizing can be as follows: thermosetting resin, in particular of the phenol-formaldehyde type 50 to 100 parts by weight of solids in particular 50 to 70 - urea 50 to 0 parts by weight in particular 50 to 30 with a total resin + urea = 100 parts by weight of dry matter ammonium sulphate 0 to 5 parts by weight in particular 1 to 3 ammonia 0 to 10 parts by weight (on the basis of a 20% ammonia solution) in particular 2 to 6 - silane 0 to 2 parts by weight mineral oil 0 to 20 parts by weight

In a second embodiment, the sulfite and / or at least one precursor thereof is applied separately from the sizing on the mineral wool, for example, it can be sprayed in the aqueous phase near the spray crown. sizing, in particular by placing two spraying crowns superimposed on the path of the mineral wool in the direction of the receiving member, a crown (preferably the first in the direction of progression of the wool) being intended for sulfite and l 'other crown being intended for gluing. According to one embodiment of the invention, the sizing comprises as a mixture:

50 to 90 parts by weight of a phenol-formaldehyde resol having a content of free formaldehyde less than or equal to 25% by weight relative to the weight of dry matter of resin and a content of free phenol less than or equal to 2.5% by weight relative to the weight of dry matter of resin obtained by condensation in basic medium of phenol (P) and formaldehyde (F) in a molar ratio F / P of the order of 2 to 5 until the product of acid neutralized condensation has a water dilutability greater than or equal to 1000%;

10 to 50 parts by weight of urea.

The above sizing characteristics have been found to be excellent in limiting the emissions of volatile organic compounds such as phenol and formaldehyde, while reducing the amount of ammonia released on the production line.

According to another advantageous embodiment, the sizing is substantially free of urea or urea derivative. Sizing of this type is described in application FR 2 788 514 as remarkable in the reduction of the toxic emissions which it provides, in particular emissions of isocyanates, and in particular of methyl isocyanate during the manufacture of insulating products in mineral wool.

The mineral wool thus glued being then treated in an oven for the polymerization of the sizing resin, it is necessary to ensure that the conditions of the heat treatment in an oven (temperature, residence time) do not affect the stability sulfite. In general, the conventional manufacturing conditions are entirely compatible with the use of sulfite according to the invention.

The invention applies to insulation products based on all types of mineral wool, both glass wool and rock wool. It finds a particularly interesting application when the product consists of glass wool or rock wool capable of dissolving in a physiological medium (so-called "biosoluble" wool), usually fairly sensitive to humidity. Examples of such materials are described in particular in EP-A-0 412 878, WO-A-95 31 411, WO-A-95 32 927, WO-A-93 22 251,

EP-A-0 459 897, WO-A-96 04 213, WO-A-95 31 410.

These materials generally have a dissolution rate in saline solution simulating a physiological medium, of at least 30, in particular at least 40 or 50 ng / cm ² per hour, measured at pH 4.5, and of at least 30, in particular at least 40 or 50 ng / cm ² per hour, measured at pH 7.5.

Among the parameters influencing the sensitivity to water of these materials, we can cite their fairly high content of alkaline oxides, which can be of the order of 8 to 25%, especially 14 to 20% by weight in preferred glass compositions.

To this is added a boron oxide content in general of the order of 2 to 18%, in particular at least 4%, or even at least 7%, in particular from 4 to 13% by weight, or even from 7 to 15%.

In particular, the content of sodium oxide Na2θ may be greater than or equal to 16% by weight, for example of the order of 16.5 to 19% by weight, with a content of potassium oxide of the order of 0 , 2 to 0.5% by weight. In a particular example, according to EP-A-412 878, the composition is as follows:

- CaO 5 at 10% - MgO O at 5%

especially 7 to 12% - F 0 to 1.5%

- impurities <2%

In another particular example, according to WO-A-95 32 927, the composition is as follows:

- CaO + MgO 10 to 16%

- BaO 0 to 1%

- impurities 0 to 2%

In this regard, the invention also relates to an insulation product, in particular thermal and / or acoustic, based on wool. mineral provided with a sizing based on thermosetting resin, in particular a phenolic resin, in which the sizing contains at least one sulfite and / or at least one precursor thereof, which improve the mechanical resistance of the product after aging, in particularly in a humid environment, this product can have any of the above characteristics.

In general, an improved insulation product according to the invention may have the usual density characteristics, the latter generally being at least 10 kg / m ³ . In a preferred embodiment, the insulation product has a density of at least 50 kg / m ³ , in particular at least 80 kg / m ³ . These products, classified as heavy, are mainly used in roofing applications and are particularly exposed to humidity due to thermal cycles and atmospheric condensation. According to the invention, they retain a good level of mechanical resistance after aging under these conditions.

The invention finally relates to the use of at least one sulfite and / or at least one precursor thereof with a sizing of insulating product, in particular thermal and / or acoustic, based on mineral wool to improve the mechanical resistance after aging, in particular in a humid environment, of the product.

Other characteristics and advantages of the invention will appear from the description of the detailed examples which follows.

EXAMPLE 1 Glass wool is produced by the internal centrifugation technique, in which the molten glass composition is transformed into filaments by means of a tool called centrifugation plate, comprising a basket forming a chamber for receiving the molten composition. and a peripheral band pierced with a multitude of orifices: the plate being rotated about its axis of symmetry arranged vertically, the composition is ejected through the orifices under the effect of centrifugal force and the material s' escaping from the orifices is drawn into filaments with the assistance of a current of drawing gas. Conventionally, a sizing spray crown is arranged below the fiberizing plates so as to distribute the sizing composition regularly over the glass wool which has just been formed. The mineral wool thus glued is collected on a belt conveyor equipped with internal suction boxes which make it possible to retain the mineral wool in the form of a felt or a sheet on the surface of the conveyor. The conveyor then circulates in an oven where the polycondensation of the sizing resin takes place. The composition of the glass (hereinafter designated NI) is of the type described in EP-A-0 412 878.

It is a so-called biosoluble glass, that is to say capable of dissolving in a physiological medium. This type of glass is particularly sensitive to exposure to atmospheric or liquid water for a prolonged period, the hydrolytic attack of the glass being able to degrade the glass fibers with a potential loss of mechanical properties.

Three sizing compositions free of urea or urea derivatives, obtained in accordance with patent FR 2 788 514, are used. The first sizing composition is as follows (in parts by weight):

- formo-phenolic resin modified with diethanolamine RI

100 parts by weight of solids (- formaldehyde (F) / ρhenol (P) = 2.8; -37% by weight of dry extract;

- free phenol 0.4%, free formalin 2, 1% measured just after neutralization of the resin by sulfamic acid)

- mineral oil 16 parts by weight

- ammonium sulphate 2 parts by weight - ammonia 20% 6 parts by weight silane 0.3 parts by weight

The silane consists, as in the following examples, of Y-aminopropyltriethoxy silane. The second sizing composition differs from the first by the addition of 5 parts by weight of ammonium sulfite in the form of water-soluble crystals.

The third sizing composition differs from the first by the addition of 5 parts by weight of sodium sulfite.

The size is diluted with water before being sprayed, the dilution rate and the spray rate being suitable for depositing on the order of 3 to 7%, generally on the order of 4.5 to 5 % of dry matter relative to the weight of glass wool. The insulating product manufactured in the three tests of this example is a panel with a density of the order of 19 kg / m ³ , with a surface mass of 570 g / m ² and having a loss on ignition of 7%.

The products obtained are subjected to tensile strength measurements (expressed in gf / g) just after manufacture and after aging for 45 minutes in an autoclave at 105 ° C.

We measure for the first, second and third sizing compositions:

477 and 279 gf / g, a loss of 42%;

486 and 293 gf / g, a loss of 40%; and - 494 and 198 gf / g (60% loss).

It therefore appears that the addition of ammonium sulfite, in the case of this relatively low density insulating product, has the effect of increasing the tensile strength after manufacture and also of reducing the loss of this property during the aging. On the other hand, the addition of sodium sulfite has the effect of considerably aggravating the loss of mechanical properties over time.

EXAMPLE 2

Example 1 is reproduced with other sizing compositions characterized by the low emissions of volatile compounds such as phenol and formaldehyde as well as the quantity of ammonia released on the production line.

The first sizing composition, expressed in parts by weight of dry matter, is as follows: R2 phenophenolic resin + 20% urea + ammonia premix

75 + 25 + 2 parts by weight

(F / P = 2.8; 38.4% by weight of dry extract; free phenol 0.45%, free formalin 2.4% measured just after neutralization of the resin by sulfamic acid)

- mineral oil 9.5 parts by weight

- ammonium sulphate 2 parts by weight - silane 0.5 parts by weight

The second sizing composition differs from the first by the addition of 2 parts by weight of ammonium sulfite.

The size is diluted with water before being sprayed, the dilution rate and the spray rate being suitable for depositing on the order of 3 to 7%, generally on the order of 4.5 to 5 % of dry matter relative to the weight of glass wool.

The insulating product produced in the two tests of this example is a panel with a density of the order of 11 kg / m ³ , with a surface mass of 880 g / m ² and having a loss on ignition of 4.5 %. The products obtained are subjected, as in the previous example, to the tensile strength measurements (expressed in gf / g) just after manufacture on the one hand, and after 45 minutes' stay in an autoclave at 105 ° C. on the other hand.

The first and second sizing compositions are measured respectively:

- 211 and 127 gf / g (loss = 39.8%) and

- 201 and 141 gf / g (loss = 30.2%).

It is noted that the addition of ammonium sulfite reduces the tensile strength after manufacture but makes it possible to maintain this property at a higher level after aging.

EXAMPLE 3 In contrast to the previous two, this example relates to relatively high density insulating products which are produced from sizing compositions of the same type as those of Example 2, that is to say compositions capable of reducing the emissions of volatile organic compounds as well as the quantity of ammonia released on the production line. Two sizing compositions are used. The first consists, in parts by weight of dry matter, of phenophenolic resin R2 + urea in premix 75 + 25 parts by weight (-F / P-2.8; -38.2%) by weight of dry extract ;

- free phenol 0.5%, free formalin 2% measured just after neutralization of the resin by sulfamic acid)

- ammonium sulfate 1, 2 parts by weight

- silane 0.5 parts by weight - silicone 1.5 parts by weight

The silicone is sold by the Dow Corning Company under the reference Q2-1581.

The second sizing composition differs from the first by the addition of 2 parts by weight of ammonium sulfite. The size is diluted with water before being sprayed, the dilution rate and the spraying rate being here adapted to deposit on the order of 7 to 15%, preferably on the order of 9 to 10% of dry matter. relative to the weight of glass wool.

The insulating product produced in the two tests of this example is a panel with a density of the order of 128 kg / m ³ , with a surface mass of 2550 g / m ² and having a loss on ignition of 9.8%.

Pull-out resistance (in kPa) and Compression resistance (in kPa, for a reduction in thickness of 10% and 25%) are conventionally measured immediately after manufacture, after aging for 15 minutes in an autoclave at 105 ° C, then after accelerated aging (NORDTEST) for 7 days (168 hours) in a climatic chamber regulated at a temperature of 70 ° C and a relative humidity of 90-95%. The tear strengths measured on the products based on the first, respectively the second sizing composition are:

8.9, 5.8 and 0.7kPa (loss = 92.1%);

9.8, 6.7 and 1.9 kPa (loss = 80.6%). The compressive strengths measured on the products based on the first, respectively the second sizing composition are:

- for a 10% thickness reduction:

21.0, 16.8 and 6.2kPa (loss = 70.5%);

21.4, 15.6 and 12, lkPa (ρerte = 43.5%); and - for a 25% thickness reduction:

78.7, 63.8 and 28.4kPa (loss = 63.9%);

79.8, 58.2 and 33.5 kPa (ρerte = 58.0%).

It is found in all cases that the addition of ammonium sulfite improves the mechanical properties of the insulating product immediately after its manufacture, and reduces the degradation of these properties during the aging of the product.

On the other hand, the change in thickness after accelerated aging of 7 days as defined above is measured on each of the two products of this example. These modifications are 14.5, respectively 3.0%, again reflecting better resistance to aging of the product comprising ammonium sulfite.

Claims

1. Method for improving the mechanical resistance after aging, in particular in a humid environment, of an insulating product, in particular thermal and / or acoustic, based on mineral wool provided with a sizing comprising a thermosetting resin, in particular a phenolic resin, characterized by adding at least one sulfite and / or at least one precursor thereof to the sizing during the manufacture of the product, it being understood that said sulfite does not react with formaldehyde into a hygroscopic product.

2. The method of claim 1, wherein said sulfite is ammonium sulfite.

3. Method according to claim 1 or 2, wherein the weight share of said sulfite introduced and / or coming from the reaction of said precursor (s) is less than 20%, in particular of the order of 0.01 to 10% relative to the weight of dry matter of phenolic resin and urea.

4. Method according to one of claims 1 to 3, wherein said sulfite and / or at least one precursor thereof is mixed with the sizing before application to the mineral wool.

5. Method according to one of claims 1 to 3, wherein said sulfite and / or at least one precursor thereof is applied separately from the sizing on the mineral wool.

6. Insulation product, in particular thermal and / or acoustic, based on mineral wool provided with a sizing based on thermosetting resin, in particular a phenolic resin, in which the sizing contains at least one sulfite and / or at least a precursor thereof, which improve the mechanical resistance of the product after aging, in particular in a humid environment.

7. Insulation product according to claim 6, in which the mineral wool consists of glass wool or rock wool capable of dissolving in a physiological medium, in particular containing a proportion of alkaline oxides of the order of 8 to 25% by weight. mineral wool.

8. Insulation product according to claim 7, in which the mineral wool has a speed of dissolution in saline solution simulating a physiological medium, at least 30, in particular at least 40 or 50 ng / cm ² per hour, measured at pH 4.5, and at least 30, in particular at least 40 or 50 ng / cm ² per hour, measured at pH 7.5.

9. Insulation product according to one of claims 6 to 8, which has a density of at least 10 kg / m ³ , in particular at least 50 kg / m ³ , in particular at least 80 kg / m ³ .

10. Use of at least one sulfite and / or at least one precursor thereof with a sizing of insulating product, in particular thermal and / or acoustic, based on mineral wool to improve the mechanical strength after aging, in particularly in a humid environment, of the product.

11. Use of at least one sulfite and / or at least one precursor thereof according to claim 10, as a mixture in the sizing or as a separate spray.

12. Sizing composition for insulating product, in particular thermal and / or acoustic, with improved mechanical resistance after aging, in particular in a humid environment, comprising a thermosetting resin and at least one sulfite and / or at least one precursor thereof .